Cavernous haemangioma of the temporal bone. Cavernous haemangioma of the temporal bone is a rare lesion and nearly always of limited extent. A case of a large and rapidly progressive temporal bone haemangioma in a child is presented. Negative angiography led to biopsy at which profuse and troublesome haemorrhage was encountered. Subsequent Red Blood Cell labelled scan demonstrated blood pooling in the lesion. The combination of positive RBC labelled scan and negative angiography can only occur in lesions in which blood pooling takes place, enabling biopsy with its hazards to be avoided. The tumour was resected using a skull base, infratemporal approach. Morbidity was minimal. There was no evidence of recurrence at a 15 month follow-up.


Early marked arytenoid calcification in a case of suspected foreign body. A case of early marked calcification of the arytenoid cartilages is presented in a patient with a suspected pharyngeal foreign body. The calcification on X-ray had the appearance of the expected foreign body. Calcification of the arytenoid cartilages is discussed.


Pharyngolaryngeal migration: a delayed complication of an impacted bullet in the neck. We present a case of a patient who sustained a bullet wound to the mouth and face resulting in impaction of the foreign body in the neck. This was initially managed conservatively until migration into the supralaryngeal area occurred. This resulted in airway obstruction, dysphagia, and dysphonia necessitating resuscitation and per-operative intrapharyngeal removal. Bullet wounds are uncommon in this country and experience with these cases is lacking. This paper discusses the various management options and the mechanism of how the bullet became lodged in the tissues of the neck.


Diffuse tuberculous parotitis.

Diffuse tuberculous parotitis. Parenchymatous parotid tuberculosis diffusely affecting the entire gland is very rare. We present a case, associated with a primary pulmonary focus, that was confirmed after positive identification of alcohol and acid-fast bacilli in gastric washings. Both sites of infection resolved with quadruple anti-tuberculous chemotherapy.


Osteomyelitis of the cervical spine following laryngectomy. Only one case of osteomyelitis of the cervical spine following laryngectomy for carcinoma of the larynx has been reported in the literature to date. We report an unusual case of osteomyelitis of the cervical spine following treatment of laryngeal carcinoma by radiotherapy (RT) and subsequent laryngectomy and discuss the relevant literature.


Foetal warfarin syndrome--a complex airway problem. Case report and review of the literature. Premature cartilaginous calcification and nasal hypoplasia following first trimester exposure to warfarin are known as the Foetal Warfarin Syndrome (FWS). There are over 40 cases reported in the literature, many of which describe breathing and feeding difficulties in the first few months of life. We report a case where a child had had difficulties breathing and feeding in the first months of life. These had been attributed to nasal hypoplasia. After proper ENT assessment the child benefitted from adenoidectomy. ENT surgeons should be aware of the syndrome as more women of child bearing age are taking warfarin following cardiac surgery and treatment of thromboembolic disease. ENT surgeons may be asked to review these children who often present with airway and feeding problems which have been attributed to nasal hypoplasia.


A case of Merkel-cell carcinoma metastatic to the tonsil. Metastatic tumours are rare in the tonsil. We describe a 69-year-old male patient who had previously undergone a resection of a Merkel-cell tumour of the left forearm and subsequently presented with a left tonsillar tumour. Biopsy revealed a metastatic Merkel-cell carcinoma. Our patient is the first described case of Merkel-cell carcinoma metastasizing to the tonsil. The clinical and histopathological picture of this rare tumour is presented, along with a review of literature.


A destructive false aneurysm of the maxillary sinus. A false aneurysm of the internal maxillary artery presented with clinical and radiological features suggestive of a malignant tumour of the maxillary sinus. This case illustrates a complication of antral lavage and an unusual clinical, radiological and pathological entity.


Analysis of dynamic and stationary pattern formation in the cell cortex. We study a sol-gel mechanochemical model for cellular cytoplasm. Using conservation equations and a force balance equation, we derive equations for the sol-gel dynamics. Regular perturbation analysis suggests the growth of patterns which may be either dynamic or stationary, depending on parameter values. Nonlinear analysis, which indicates that these patterns remain bounded, is confirmed by numerically solving the mechanochemical equations. We use these analytical and numerical results to model two different biological problems: the dynamic formation of filopodia in nerve growth cones, and the growth of microvilli in epithelial cells.


A modeled time-varying density function for the incubation period of AIDS. Building on the Weibull distribution, we develop a modeled time-varying density function of the incubation time between exposure to HIV infection and full-blown AIDS. This approach leads to a series of cohort-specific density functions that take into account the increasing impact of new therapies such as zidovudine (AZT). The resulting modeled density functions are studied in detail, particularly with regard to their modes and medians. The mode is sensitive to changes in the period incubation time distribution, with even a possibility of a bimodal distribution for certain combinations of the parameters that determine the rate at which the period median incubation time changes. An important substantive result is that when a period median incubation period slowly increases to some leveling off value, say m(xc), then it is surprisingly early on that cohorts of infected individuals have a median incubation period very close to that ultimate value m(xc).


Gestational diabetes mellitus.

Gestational diabetes mellitus. The prevalence of gestational diabetes mellitus by screening 25,997 pregnant women in Rajavithi Hospital during a two-year-period was 2.02 per cent. Of the 312 gestational diabetes patients available for the study, their mean age was 29 years. Risk factors included a BMI before pregnancy of more than 26 (26.5%), family history of diabetes mellitus (23.1%), history of abortion (14.4%), and history of fetal death in utero (3.2%). Macrosomia, congenital anomalies and cesarean delivery were found significantly more common in gestational diabetic patients compared to normal pregnancy.


The course of clinical COPD in Thailand. Spirometry and outcome of 96 cases who were clinically diagnosed as having COPD were studied. Ninety-two cases had significant airway obstruction. Of these 92 cases, initial bronchodilator responses were evaluated in 73 cases. Twenty-six cases were responders (CRAO), while 47 cases were nonresponders (COPD). The average median survival of the whole group was 4 years and 5-year survival was 30 per cent. The annual change in FEV1 in both COPD and CRAO group were fluctuating, with a tendency to decrease in the former and increase in the latter. Spirometric parameters were found to be different between the survivors and nonsurvivors, these included initial PFEV1, PFVC, PFEF 25-75 per cent and postbronchodilator FEV1 and FEF 25-75 per cent. Inspite of the differences, an initial response to bronchodilator could not predict a better outcome for CRAO as compared to COPD. It was concluded that most clinical COPD who had progressive symptoms had significant airway obstruction and shorter survival. Due to fluctuating FEV1 during the course, the initial spirometry and degree of bronchodilator response were not accurate enough to predict subsequent outcome. Long-term follow-up on spirometry and response to bronchodilator should be individually evaluated.


Long term efficacy of hepatitis B immunoprophylaxis in neonates at risk: using different vaccine and schedule. Passive and active immunization for the prevention of hepatitis B virus (HBV) transmission in neonates born to HBeAg positive carrier mothers was studied using different kinds and dosages of combined hepatitis B immunoglobulin (HBIG) and hepatitis B vaccine. The long term efficacy of these various immunoprophylaxis programmes was evaluated up to 3 years of age. Eight groups of neonates, 20 in each group, received HBIG either the usual dose of 100 IU intramuscularly or intravenously or increased dose to 200 IU, combined with different kinds of hepatitis B vaccine either in full dose or half dose given in different schedules of 0, 1, 2 or 0, 1, 6 months, in some groups also received a booster dose at 12 months. After follow-up for 3 years, there were no statistical significant differences of the results between these 8 different immunoprophylaxis programmes, either in the rate of seroconversion or the protective efficacy as well as the antibody response (anti-HBs titer). The seroconversion rates after 3 years of age in all 8 groups were in the range of 63.6 to 92.9 per cent. The protective efficacy rates at 3 years of age were in the range of 69.7 to 100 per cent.(ABSTRACT TRUNCATED AT 250 WORDS)


Operative treatment of plantar fasciitis. Ten patients undergoing 12 fasciotomy by stripping the plantar fascia and superficial plantar muscles from the calcaneus have been reviewed for an average of 24.9 months after the operation. All patients failed to respond to conservative treatment by anti-inflammatory medication, heel pads and local steroid injections for a duration of 6 months to 3 years (average 15 months). There were 7 females and 3 males. Their work was of a light nature and none of them were professional athletes. The results indicated 91.6 per cent excellent, 8.4 per cent good and no failure. Complete pain relief at rest and walking was obtained in 11 of 12 for an average of 11.75 months (from 8 months to 18 months) after surgery. There was only 1 of 12 who had mild pain at walking that did not impair activity. All patients could return to their jobs about 4-6 weeks after surgery. Bloodless operation (under tourniquet control) was performed under general anaesthesia.


The study of discriminant values of dyspeptic symptoms for identifying the etiology of dyspepsia. This prospective study aims to determine whether specific symptoms or group of symptoms could positively discriminate the etiology of patients who present with dyspepsia. Two hundred and eight patients were studied and 111, 55, 35 patients were classified as non-ulcer dyspepsia, peptic ulcer disease and hepatobiliary disease, respectively. All patients completed a structured history questionnaire by personal interview and completed investigation with complete blood count, stool examination, liver function test, HBsAg, HBsAb, ultrasonography of the abdomen and endoscopy. Variable of interest and variables of statistical significance by univariate analysis were put into discriminant function of logistic model for discrimination. The results suggest that anorexia and no periodicity of epigastric pain significantly discriminated non-ulcer dyspepsia from peptic ulcer disease and hepatobiliary disease, pain occurring before a meal or when the patient was hungry and nocturnal epigastric pain significantly discriminated peptic ulcer disease from hepatobiliary disease.


Isolation of Campylobacters from the canals of Bangkok metropolitan area. The 100 ml of canal water samples of 36 canals in Bangkok Metropolitan Area were examined in three periods starting from July-September 1988, November 1988-January 1989 and February-April 1989. Each time the 52 water samples were checked. Of 156 water samples, 116 strains of Campylobacter species were isolated. They were 63.79 per cent (74 strains) of C. cryaerophila and 36.21 per cent (42 strains) of C. cryaerophila-like organisms. The differentiation was determined by urease activity test. C. cryaerophila was isolated from 44.23 per cent (23 strains), 51.19 per cent (27 strains) and 46.15 per cent (24 strains) and also C. cryaerophila-like organism from 28.85 per cent (15 strains), 19.23 per cent (10 strains) and 32.69 per cent (17 strains) of the 52 samples during each period respectively. Since C. cryaerophila and C. cryaerophila-like are aerotolerant Campylobacter, they grow well in aerobic conditions at 25 degrees-36 degrees C. On the contrary, thermophilic Campylobacter such as C. jejuni, C. coli and C. laridis require atmosphere containing 5 per cent O2, 10 per cent CO2, 85 per cent N2 and temperature at 36 degrees-42 degrees C, so the environment in the canals is unfavorable for their growth. The etiological role of C. cryaerophila in pathogenesis in humans is still unknown, and requires furthers study. This study shows that canals can be an important source of these two Campylobacter species that might be potential pathogens in the future.


Malignant pericardial tumor in childhood: a case report diagnosed by cross-sectional echocardiogram and magnetic resonance imaging. Since primary malignant pericardial tumors are seldomly found in children, we reported a case with massive pericardial effusion. Pericardial tumor was diagnosed by cross-sectional echocardiogram. The extent of the tumor was well demonstrated by magnetic resonance imaging. The tumor was removed successfully and proved to be low grade fibrosarcoma. Modern technics can be very helpful in the diagnosis of pericardial tumor.


X-linked recessive bulbospinal neuronopathy. The first case of X-linked recessive bulbospinal neuronopathy in a Thai family is described. Clinical features of this entity were discussed. Although two members of this family had classical features of X-linked recessive bulbospinal neuronopathy, there were some differences in distribution of weakness among the affected members. This variation among the members of the affected family was firstly described. The clinical features of this disease especially the associated gynecomastia and essential tremors are distinctive and it is possible to diagnose it even in a sporadic case. Although, the prominent feature of the disease is atrophy and fasciculation of muscles, this entity is not a pure anterior horn cell disorder and should be better classified as a multisystem disorder due to multiple organ involvement.


Ciliogenesis in the human oviduct epithelium during the normal menstrual cycle. Ciliogenesis has been investigated in the human oviduct epithelium during the normal menstrual cycle. Both centriolar and acentriolar pathways were involved in the replication of basal bodies. The centriolar pathway, in which procentrioles generate with the aid of preexisting diplosomes, played a minor role in the human oviduct. In the acentriolar pathway, fibrous granules were the first structure which appeared in the course of ciliogenesis and they initially occurred in association with the Golgi apparatus or free ribosomes. Subsequently deuterosomes arose in the aggregates of fibrous granules or apart from fibrous granules, and then microtubules-containing procentrioles originated around deuterosomes. Newly formed centrioles migrated to the apical cytoplasm with accompanying deuterosomes, and ciliary shafts extended first at the periphery of the luminal surface of ciliogenic cells. Deuterosomes as well as fibrous granules were considered to be related to the rootlet formation. Replicaion of basal bodies and protrusion of ciliary shafts mostly occurred during the proliferative phase of the menstrual cycle; however, a small number of fibrous granules indicating the ciliogenesis were still observed in some ciliated cells during the secretory phase. Ciliogenic cells in early stages of ciliogenesis contained secretory granules-like vesicles in the apical cytoplasm, suggesting that the ciliated cells are differentiated from secretory cells in the late secretory phase on demand.


Freeze-substitution and X-ray microprobe analysis of amine-storage organelles of rat platelets after treatment with reserpine. Freeze-substitution was successfully used to determine the elemental composition of the amine storage organelles of rat platelets after treatment with reserpine. Conventional electron microscopy of platelets fixed with glutaraldehyde and OsO4 revealed many empty vesicles indicating the liberation of 5-hydroxytryptamine from the amine storage organelles. However, the organelles were totally filled with an osmiophilic material in platelets freeze-substituted with OsO4-acetone. Freeze-substitution of platelets with pure acetone without OsO4 revealed also the presence of an electron-opaque material in the organelles. The emission spectra of X-ray generated by the spot analysis of the organelles exhibited Na-K alpha, Mg-K alpha, P-K alpha, K-K alpha, and Ca-K alpha. A semi-quantitative comparison of elemental concentrations in the amine storage organelles between reserpine-dosed rats and normal intact controls showed that K was significantly higher in controls, while the content of other elements was similar.


A method for simultaneously revealing both the cytoskeleton and membranous cell organelles for scanning electron microscopy, and its application to rat tissues. Perfusion with a dilute saponin solution before perfusion and immersion fixation with 0.5% glutaraldehyde and 0.5% formaldehyde, followed by routine processing for high-resolution scanning electron microscopy, allows a variety of cytoskeletal elements to be well preserved. Membranous organelles are also clearly seen, allowing the three-dimensional relationships of membranes and filaments within the cell to be directly observed. In particular, in the rat intermediate filaments were seen to terminate on smooth endoplasmic reticulum and nuclear envelopes of intestinal epithelia, and to form networks between mitochondria and rough endoplasmic reticulum in podocytes of renal glomeruli.


Neural cell adhesion molecule of taste buds. The distribution of the neural cell adhesion molecule (N-CAM) in the taste buds of adult and developing mice was studied by use of an immunocytochemical technique. In adult mice, nerve fibers and some elongated taste bud cells reacted with anti-N-CAM antibody. Immunoelectron microscopic observation showed that only type-III (gustatory) cells, which have afferent synaptic contacts with the nerves, were N-CAM positive in the taste buds. At day 0 after birth, taste buds of the developing mice first appeared in the circumvallate papillae, and N-CAM positive cells, which corresponded to type-III cells having afferent synapses, were found. This result suggests that N-CAM is involved in formation of the synaptic contacts between type-III cells and nerves in the taste buds.


Application of the environmental SEM in human dentin bleached with hydrogen peroxide in vitro. The environmental SEM (E-SEM) can be used unfixed biological samples under a low vacuum and wet condition. In this study, the fractured dentin of unfixed human teeth was treated with a 30% hydrogen peroxide solution (H2O2) for the examination of tooth-bleaching prior to the E-SEM and a conventional SEM. The peritubular matrix (PM) always showed a few cracks along the long axis of a dentinal tubule, and the ends of fine fibrils rose to the smoothly changed surface of the intertubular matrix (IM). The E-SEM with non-fixation and the conventional SEM following fixation indicated that the hydrogen peroxide solution easily permeated the PM and dissolved the non-fibrillar substance including the cracks of the PM by the constriction. In the IM, the solution may partially dissolve the organic parts within mineralized fibrils as well as non-fibrillar substance between the fibrils, although these remnants might precipitate again there.


High resolution electron microscopy in the dentino-enamel junction. The direct crystal connection at the dentino-enamel junction was investigated using high resolution electron microscope. High resolution electron microscopy revealed that lattice fringes of dentine crystals entered into and directly contacted with those of enamel crystals. In such junction, intricate and irregular tilt boundaries were located in fusion levels. Dentine crystals were closely joined at the outermost dentine surface where fusions occurred. At the fusion level, dislocation appeared to form tilt boundaries. The tilt boundaries at the fusion levels in dentine crystals had more regular curvature than those at the dentino-enamel junction. These findings suggest that growth of dentine crystals brings direct connection with enamel crystals. Furthermore, it is suspected that dentino-enamel junction is weak in mechanical and/or chemical attacks.


Backscattered electron imaging by scanning electron microscopy of regenerating peripheral nerve axons immunostained with antineurofilament antibody. To demonstrate three-dimensional architecture of regenerating axons growing through basal lamina tubes in cryoinjured nerve graft, backscattered electron (BSE) imaging in a scanning electron microscope (SEM) was used to visualize immunostained axons. Regenerating axons immunostained with an antibody against the 200 kD neurofilament protein (RT97) were clearly visualized in BSE images as bright components pursuing an irregular, often spiral course within the basal lamina tubes, and commonly branching within the tubes. The morphology of these structures corresponded closely to that of putative regenerating axons in SEM preparations following application of the potassium hydroxide-collagenase digestion method. The present approach, however, is a considerable improvement on the latter, providing three-dimensional information together with the identification of regenerating axons.


Testosterone-induced suppression of self-healing Plasmodium chabaudi malaria: an effect not mediated by androgen receptors? This study investigates whether androgen receptors (AR) mediate the suppressive effect of testosterone on self-healing Plasmodium chabaudi malaria. Our data show the following. (1) Female and castrated male mice of the inbred strain C57BL/10 self-heal and survive infections when challenged with 10(6) P. chabaudi-parasitized erythrocytes. However, self-healing is prevented when circulating testosterone levels are high as in intact males or in females and castrated males pretreated with 0.9 mg testosterone twice a week for 3 weeks. (2) The lethal outcome of P. chabaudi in intact males is not affected by different doses of AR blockers such as cyproterone acetate, cyproterone, flutamide and nilutamide when applied at least 3 weeks before infection and during infection. Also, these AR blockers do not impair the testosterone-induced lethal outcome of infections in testosterone-treated females and castrated males. (3) Tfm mice possessing mutant non-functional ARs and normal 'male' testosterone levels succumb to infection with P. chabaudi. However, the corresponding wild-type mice possessing functioning ARs are able to resist P. chabaudi infections at low circulating testosterone levels. (4) In contrast to testosterone, testosterone metabolites such as 5 alpha-dihydrotestosterone, 5 beta-dihydrotestosterone, androsterone and 1-dehydrotestosterone cannot suppress self-healing in castrated male B10 mice. Our data suggest that testosterone suppresses the development of protective immunity against P. chabaudi malaria, and that this immunosuppressive effect of testosterone is not primarily mediated by the classical AR response.


Noradrenergic peripheral denervation of the female rat accelerates the positive feedback mechanisms resulting in pubertal ovulation, and blocks the modifications induced by administration of testosterone propionate at birth. The noradrenergic innervation of the ovary of prepubertal rats causes an inhibitory response of the follicles to gonadotrophins, leading to ovulation. We investigated the possibility that noradrenergic peripheral denervation at birth, produced by treatment with guanethidine, modifies the positive feedback effects of gonadotrophins and oestradiol in prepubertal rats, and also the possibility that peripheral denervation can modify the anovulatory syndrome induced by androgenization at birth. Noradrenergic peripheral denervated rats of 18 days of age treated with pregnant mare serum gonadotrophin (PMSG) ovulated 96 h later, while normal animals did not ovulate (4/9 vs 0/12, P < 0.05) and the number of ova shed was lower than in rats which ovulated spontaneously at first vaginal oestrus (3.5 +/- 0.6 vs 8.3 +/- 0.4 (S.E.M.), P < 0.01). Oestradiol benzoate (10 micrograms) did not induce ovulation in either normal or denervated animals (0/11 and 0/11). The anovulatory syndrome induced by the administration of testosterone propionate (75 micrograms) at birth was partially blocked by noradrenergic peripheral denervation (4/7 ovulated vs 0/10). The results suggest that some neural information arising from the ovary modulates, in an inhibitory way, the stimulatory feedback mechanisms required to induce ovulation. Partial inhibition of the anovulatory syndrome resulting from androgenization caused by peripheral noradrenergic denervation suggests that noradrenergic neural information sent by the ovary to the hypothalamus results in a decreased concentration of noradrenaline in the hypothalamus and in the aromatization of androgens to oestrogens.


Oestradiol increases the extracellular levels of amine metabolites in the ewe hypothalamus during anoestrus: a microdialysis study. Giving a subcutaneous oestradiol implant during anoestrus to ovariectomized ewes inhibits pulsatile LH secretion. This effect results from an increased negative feedback of oestradiol and depends on the synthesis of biogenic amines, mainly from the mediobasal hypothalamus. In the present study, we examined the effect of oestradiol on the extracellular levels of amines and their metabolites. Eight ewes were sampled by microdialysis from the lateral retrochiasmatic area, including the dopaminergic A15 nucleus, during inhibition of LH secretion by long days. Two dialysis sessions were carried out on each ewe; one after a 10-day oestradiol treatment and the other one after 10 days without oestradiol treatment. Half of the ewes were first oestradiol-treated then untreated, the other half received the treatment in the reverse order. Oestradiol caused a decline in pulsatile LH secretion without affecting the secretion of prolactin. This steroid also led to a significant increase in the levels of amine metabolites: 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindoleacetic acid in the extracellular medium. These results demonstrate the effect of oestradiol on aminergic activity as related to changes in hormonal secretions during long days (16 h of light per 24 h). Thus our data support the hypothesis that amines inhibit gonadotrophic secretion during anoestrus in the ewe and suggest that there is an activation of the aminergic neurones from the retrochiasmatic area in this regulatory mechanism.


Plasma atrial natriuretic peptide in vasopressin deficiency: the effects of acute water deprivation in rats. Plasma concentrations of atrial natriuretic peptide (ANP) and other renally active hormones were measured in Long-Evans (LE) rats and vasopressin-deficient Brattleboro rats with diabetes insipidus (DI) in conditions of water repletion and deprivation, and in DI rats following chronic vasopressin replacement. In water-replete rats, vasopressin deficiency was associated with elevated circulating ANP and angiotensin II (AII) concentrations, while plasma adrenal steroid concentrations were depressed by comparison with LE rats. These differences were fully reversed after 7 days of vasopressin replacement in DI rats to restore normal water turnover. Water deprivation for 4 h had little effect on plasma tonicity or hormone profile in LE rats. In contrast, however, the unreplaced fluid loss during 4-h water deprivation in the DI rat was associated with a marked increase in plasma tonicity evident within 30 min. Plasma ANP concentrations fell substantially to levels below those in LE rats, coincident with a rise in adrenal steroid levels and independent of any clear change in AII. These changes in circulating ANP concentration were directly correlated with changes in plasma Na+ concentration, osmolality and tissue water content in the DI rats, underlining the importance of body fluid status in modulating the secretion of ANP. These data clearly show that plasma ANP concentration is increased in vasopressin deficiency, but emphasize the sensitivity of circulating hormone levels in vasopressin-deficient animals to acute changes in the state of hydration, underscoring the complex and labile interaction between body fluid and hormonal factors involved in the control of ANP secretion.


Prepubertal reduction of the ovarian follicle population by combined LH-releasing hormone antagonist treatment and unilateral ovariectomy influences follicle characteristics but not the ovulation rate at first oestrus. The effect on first ovulation of the massive reduction of the total pool of ovarian follicles during the infantile and late juvenile period was studied in rats. Treatment with an LH-releasing hormone antagonist (LHRH-A) during infancy (5 mg/kg body weight on days 6, 9, 12 and 15 of life) was combined with unilateral ovariectomy performed on either day 15 (early ULO) or 2-5 days before the expected day of first ovulation (late ULO). Rats were killed on the day of first or second oestrus, when blood was collected and the (remaining) ovaries were prepared for differential counting of follicles and corpora lutea. In addition, blood was sampled 8 h after ULO and the ovaries studied histologically in the group of rats which were unilaterally ovariectomized 2-5 days before first ovulation. The time of first ovulation was not influenced by treatment with LHRH-A, early or late ULO, or a combination of LHRH-A treatment and ULO. Ovulation rate after LHRH-A treatment was decreased, but was still within the normal range in intact rats and in early ULO rats compared with saline-treated controls. Serum FSH concentrations 8 h after ULO performed 2-5 days before first ovulation were similar in saline- and LHRH-A-treated rats (845 +/- 59 and 801 +/- 99 (S.E.M.) micrograms/l respectively) and had increased compared with intact controls (216 +/- 15 micrograms/l). Treatment with LHRH-A resulted in a reduction of more than 50% in healthy and atretic follicles, and late ULO reduced the number of healthy follicles even further.(ABSTRACT TRUNCATED AT 250 WORDS)


Growth hormone (GH)-binding protein in normal and GH-deficient dwarf rats. There are GH-binding proteins (GHBPs) present in the blood of many species, and these correspond to the extracellular GH-binding domain of the GH receptor. In the rat, GHBP arises by alternative splicing of the GH receptor mRNA, but little is known of the physiological role of circulating GHBP, or its relationship with episodic GH secretion. We have developed a sensitive radioimmunoassay based on recombinant GHBP, and have measured rat GHBP levels in small samples of plasma from normal and GH-deficient dwarf rats. In normal adult rats, GHBP levels were two- to threefold higher in females than in males (16.6 +/- 0.8 vs 6.4 +/- 0.4 micrograms/l, P < 0.001), but this sex difference was not seen in dwarf rats. A continuous infusion of human GH in dwarf males raised plasma GHBP to 23.5 +/- 3.5 micrograms/l compared with 6.7 +/- 0.5 micrograms/l in sham-infused animals, whereas suppression of GH by continuous infusion of a long-acting somatostatin analogue in female dwarf rats had no effect on GHBP. In anaesthetized rats, large changes in plasma GH caused by i.v. administration of rat GH, somatostatin or GH-releasing factor did not affect GHBP acutely. Both GH and GHBP were also measured in serial blood samples from conscious normal and dwarf rats. A sexually dimorphic GH secretory pattern was observed in both strains. Males showed peaks and troughs of GH every 3 h varying over a 100-fold range, whereas females exhibited more continuous GH secretion. Despite the large fluctuations in endogenous GH, GHBP levels remained relatively constant in individual normal or dwarf males, as well as in females of both strains, and there was no significant correlation between GH and GHBP either in individual rats or as a group. Our results suggest that GHBP is GH-dependent in the longer term, and that the higher GHBP levels in female rats require their continuous GH secretory pattern. However, plasma GHBP levels remain stable and are not affected by acute changes in endogenous or exogenous GH.


Expression of the growth hormone receptor gene in chicken pituitary glands. Although GH has no direct effect on GH release from chicken pituitary glands, GH receptor mRNA similar to that in the rabbit liver was identified by Northern blot analysis in extracts of adult chicken pituitaries. Complementary (c) DNA, reverse transcribed from chicken pituitary RNA, was amplified by the polymerase chain reaction (PCR) in the presence of 3'- and 5'-oligonucleotide primers coding for the extracellular domain of the chicken liver GH receptor and was found to contain an electrophoretically separable fragment of 500 bp, identical in size to that in chicken liver. Digestion of this pituitary cDNA with NcoI produced expected moities of 350 and 150 bp. Amplification of chicken pituitary cDNA in the presence of oligonucleotide primers for the intracellular sequence of the chicken liver GH receptor produced an electrophoretically separable fragment of approximately 800 bp, similar to that in chicken liver. This fragment was cut into expected moieties of 530 and 275 bp after digestion with EcoRI. These PCR fragments were identified in extracts of the pituitary caudal lobe, in which somatotrophs are confined and account for the majority of endocrine cell types, and in the cephalic lobe, in which somatotrophs are lacking. Translation of the GH receptor mRNA in the pituitary gland was indicated by the qualitative demonstration of radiolabelled GH-binding sites in plasma membrane preparations, in pituitary cytosol and in nuclear membranes. These results provide evidence for the expression and translation of the GH receptor gene in pituitary tissue, in which GH receptors appear to be widely distributed within cells and in different cell types. GH may therefore have paracrine, autocrine or intracrine effects on pituitary function.


Site-dependent effects of experimental hypo- and hyperthyroidism on resident macrophages in extraocular muscles of rats: a quantitative immunohistochemical study. It has been suggested that the effects of dysthyroidism on resident immunocompetent cells of the extraocular muscles may play a role in the pathogenesis of Graves' ophthalmopathy. The distribution of such cells was therefore studied in extraocular muscles of rats that were made hyper- or hypothyroid by the oral administration of thyroxine or propylthiouracil respectively. Skeletal muscles were studied for comparison. The cell distributions were analysed in cryostat cross-sections subjected to a two-step immunoperoxidase method using well-characterized monoclonal antibodies against T cells, B cells, macrophages and MHC class II antigens. The extraocular muscles of control (euthyroid) rats contained numerous macrophages, fewer MHC-II positive cells and T cells and no B cells. Differences in the distribution of immunocompetent cells were found in control rats, between skeletal and extraocular muscles as well as within the various recti eye muscles. This particular tissue distribution resembles that previously reported for human extraocular and skeletal muscles. Quantitative analysis showed that experimental dysthyroidism only affected cell populations in the extraocular muscles. Significant effects on the number of macrophages were observed in the inferior rectus muscle of both hypo- and hyperthyroid rats, this was most pronounced in the orbital layer of the muscles. Both hyper- and hypothyroidism appear to affect local cell distributions in a tissue-specific manner. The presently observed site-dependent effects of dysthyroidism on local immunocompetent cell populations may have relevance for the differential involvement of muscular tissues in Graves' ophthalmopathy.


Paradoxical hypertrophy and plasticity of the testis in rats recovering from early thyroid deficiency: a growth study including effects of age and duration of hypothyroidism. The effects of various durations of postnatal hypothyroidism followed by recovery were studied on testicular growth in Long-Evans and Sprague-Dawley rats from birth to 7 months. Hypothyroidism was induced by adding propylthiouracil (PTU) in drinking water (0.1%, w/v). Recovery was induced by withdrawal of PTU. Testicular growth was reduced in rat pups by 20, 65 and 90% at days 10, 25 and 50. Upon withdrawal of PTU at weaning (25 days), testicular growth resumed and became compensatory; catch-up growth occurred by day 65. Paradoxically, testicular growth progressively increased, surpassing the control weights by 40, 50 and 100% at days 75, 90 and 210. Maximal testicular growth rate in the recovery group was 35% higher, occurred 2 weeks later and lasted 2 weeks longer than controls. Testes of rats subjected to prolonged postnatal hypothyroidism (60 or 120 days) also showed recovery and hypertrophy, amounting to nearly twice the normal maximal growth levels, after at least 6 months of recovery. Body weights of recovering rats remained always significantly below those of controls. When the suckling pups were exposed to short, week-long regimes of PTU treatment, only rats treated during the early postnatal weeks (days 1-8 or 9-16) had enlarged testes; PTU treatment during the late suckling period (days 17-24) or later had no effects. Total duration of hypothyroidism in the suckling period was positively correlated with testicular enlargement. The results indicate that hypothyroidism early in life is stimulatory to testicular growth, resulting in a paradoxical twofold increase in final testicular size which occurs even if hypothyroidism is prolonged. These effects occur similarly in different strains of rat with differing sized testes. It is suggested that there is a sensitive period for this effect, i.e. during the first 2 weeks after birth. The marked plasticity of testicular growth as shown by its recovery and hypertrophy, even after long periods of hypothyroid retardation, is unique in the body and may be a useful model for studying hormonal factors regulating testicular growth and for animal breeding and research into infertility.


Age-related discrepancies between serum and pituitary gonadotrophin, and pituitary gonadotrophin subunit mRNA responses to castration and testosterone replacement in male rats. The responses of gonadotrophin gene expression, pituitary content and serum levels to castration alone and castration plus testosterone replacement (silicone elastomer implants) were compared in male rats at 10, 30, 60 and 90 days of age. Sham-operated animals served as controls. In addition, 30-day-old castrated rats were treated with dihydrotestosterone (DHT) and diethylstilboestrol (DES). When killed 7 days after castration, the increases in serum LH (six- to eightfold; P < 0.01) and FSH (two- to fourfold; P < 0.01) were similar at all ages studied. Likewise, testosterone reversed the effects of castration in a largely similar fashion at all ages. In contrast, great age-related differences were observed in the responses of gonadotrophin subunit mRNAs to the treatments. Castration increased the common alpha subunit mRNA two- to fourfold on days 10 and 30 (P < 0.01), sixfold on day 60 (P < 0.01), but not at all on day 90. Testosterone reversed the increases at all ages, but the levels were below those of controls only at 90 days (P < 0.01). The highest increases (sixfold; P < 0.01) of LH-beta mRNA were seen on days 10 and 60, the others being two- to threefold higher (P < 0.05-0.01). Testosterone reversed this effect at 60 days and suppressed LH-beta mRNA to below the control levels at other ages (P < 0.01). Castration had no effect on FSH-beta subunit mRNA at 30 and 90 days but a four- to fivefold increase was seen on days 10 and 60 (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)


Effects of FSH on Leydig cell morphology and function in the hypogonadal mouse. The hypogonadal (hpg) mouse has a congenital deficiency in gonadotrophin-releasing hormone and the gonads consequently lack exposure to endogenous gonadotrophins during development. To determine the effect of FSH on Leydig cell function in these animals adult hpg mice were injected twice daily with FSH (2 micrograms injections) or LH (40 ng injections, the presumed LH contamination of FSH used). Following FSH treatment there was a clear stimulation of the seminiferous epithelium and in animals injected with FSH plus [3H]thymidine, the incorporation of label was largely confined to the germ cells with no apparent uptake by the Sertoli cells. In FSH-treated testes the Leydig cells contained numerous large lipid droplets, similar to the unstimulated hpg testis. There was no evidence of the interstitial hyperplasia which is observed following injection of high doses of LH (2 micrograms twice daily). There was no change in basal androgen content of the testis in vivo following FSH treatment but injection of a maximal dose of human chorionic gonadotrophin (hCG), 1 h before death, markedly increased testicular androgen content only in the FSH-treated group. Testicular androgen production in vitro was significantly increased following FSH treatment both under basal conditions (FSH-treated, 17.4 pmol/testis; control, 1.46 pmol/testis) and during stimulation by hCG (FSH-treated, 940 pmol/testis; control, 81 pmol/testis). Associated with the increased androgen production following FSH treatment there were significant increases in the activities of three steroidogenic enzymes; cholesterol side-chain cleavage (186-fold increase over control), 17 alpha-hydroxylase (103-fold increase) and 17-ketosteroid reductase (177-fold increase).(ABSTRACT TRUNCATED AT 250 WORDS)


Expansion of plasma volume by intragastric isotonic saline inhibits supraoptic neurones in rats. To determine whether an increase in plasma volume might directly influence supraoptic neurones, single cell extracellular recordings were made from magnocellular neurones of the supraoptic nucleus in urethane-anaesthetized rats as plasma volume was expanded by intragastric injection of isotonic saline. Continuous ratemeter records taken before, during and after intragastric injections of 10 ml isotonic saline showed that the firing rate of putative vasopressin cells was reduced by 2.21 spikes/s (P < 0.02; n = 9; paired t-test) after 50 min. Putative oxytocin cells, after an initial increase in firing rate which lasted approximately 30 min, showed a decrease of 0.98 spikes/s (P < 0.02; n = 6; paired t-test). A population of 93 control cells of both types had a median firing rate of 4.69 spikes/s, a comparable group of 65 cells recorded 1 h after intragastric injection had a median firing rate of 3.15 spikes/s and another group of 68 cells recorded 1 h after a second injection had a median firing rate of 2.5 spikes/s. These differences were significant (P < 0.04 and P < 0.01; Mann-Whitney U test). The haematocrit of plasma samples taken from five similarly anaesthetized control animals was 49.7%. One hour after one intragastric injection the value was significantly (P < 0.02; paired t-test) reduced to 46.7% and 1 h after a second injection it was further reduced to 42.1% (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)


Pituitary-dependent hyperadrenocorticism in a family of Dandie Dinmont terriers. Adrenocortical function studies were performed in seven Dandie Dinmont terriers with pituitary-dependent hyperadrenocorticism. The ability of dexamethasone at a dose rate of 0.1 mg/kg body weight to suppress cortisol secretion was only moderate in four out of the six dogs tested. Concentrations of alpha-melanocyte-stimulating hormone in plasma were highly increased. Responses to stimulation with corticotrophin-releasing hormone and the dopamine-antagonist haloperidol, examined in three animals, were moderate or absent. These results indicate that adrenocortical stimulation, i.e. hyperadrenocorticotrophism, was caused by pituitary lesions which were functioning autonomously. In six of the seven animals there was a very close familial relationship and the coefficients of relationship and the coefficients of inbreeding were significantly higher than in a representative control population. It was concluded that these seven related terriers with hyperadrenocorticotrophism had the biochemical characteristics of de-novo neoplasms of proopiomelanocortin-producing cells, and there was evidence for a genetic involvement in tumorigenesis.


Transforming growth factor-beta is a potent inhibitor of basal and stimulated relaxin release by porcine luteal cells maintained in monolayer culture. The effect of transforming growth factor-beta (TGF-beta) on relaxin release by porcine large luteal cells (LLC) was examined by use of a reverse haemolytic plaque assay. In this assay, mixed luteal cells were co-cultured in monolayers with protein A-coupled sheep erythrocytes. In the presence of complement and porcine relaxin antiserum, a zone of haemolysis (a plaque) developed around relaxin-releasing LLCs. The rate of plaque development in time-course experiments and the average size of plaque areas were used to monitor the rate of relaxin release and cumulative amounts of hormone respectively. Monolayers were bathed in medium containing TGF-beta alone, or in the co-presence of a stimulatory secretagogue (prostaglandin E2; PGE2). Exposure of luteal cell-containing monolayers to TGF-beta (1 ng/1-100 micrograms/1) elicited a dose-related inhibition in the rate of basal relaxin release. Minimal and maximal concentrations were approximately 10 ng/1 and 10 micrograms/1 respectively. Treatment with 1 microgram TGF-beta/1 reduced the cumulative amount of relaxin released to 63 +/- 6% of control values (mean +/- S.D., P < 0.05, n = 6; averaged over the whole course of the experimental incubation). Exposure of monolayers treated with TGF-beta to the relaxin-stimulatory secretagogue PGE2 (0.1 mumol) resulted in a significant (P < 0.05) increase in the amount of relaxin released by TGF-beta-suppressed LLCs, and restored rates of hormone release to control levels. This is evidence that TGF-beta and PGE2 interact antagonistically in the modulation of relaxin. The effect of TGF-beta was strictly time-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)


Catecholamines released from local adrenergic axon terminals are possibly involved in fine tuning of steroid secretion from zona glomerulosa cells: functional and morphological evidence. The effect of supramaximal electric field stimulation on [3H]noradrenaline (NA) release and hormone production by rat adrenal capsule-glomerulosa preparations was studied using a microvolume perfusion system. A substantial proportion (about 20%) of nerve endings (varicosities) were observed close to zona glomerulosa cells, and about half of them appeared to be catecholaminergic, as judged by the chromaffin reaction of the synaptic vesicles studied at electron microscopic level. In tissue, preloaded with [3H]NA, the release of NA in response to electrical stimulation was frequency-dependent. Reserpinization, calcium removal or inhibition of Na+ influx by tetrodotoxin completely blocked NA release by field stimulation, indicating that the release resulted from axonal activity and is of vesicular origin. Neither the alpha 2-adrenoceptor agonist xylazine nor the muscarine-receptor agonist oxotremorine affected the stimulation-evoked release of [3H]NA, suggesting that, in contrast with other neurones present in the central nervous system or in the peripheral autonomic nervous system but like those in the median eminence, these axon terminals contained few presynaptic modulatory receptors. The NA (10.20 +/- 1.79 (S.E.M.) micrograms/g, n = 9), adrenaline (24.38 +/- 5.50 micrograms/g, n = 9) and dopamine (0.35 +/- 0.09 micrograms/g, n = 6) contents of the preparations were high, as determined by high-performance liquid chromatography. Our observations that the release and content of NA is high, and that a substantial proportion of catecholaminergic axon terminals lie in close proximity to zona glomerulosa cells (median value of the distance 300 nm) or to smooth muscle cells of the vessels, suggest that NA released from local adrenergic neurones without being presynaptically modulated may play an important role in fine-tuning both steroid production and/or blood flow through the gland, itself a powerful modulator of the adrenocortical response. This local modulating effect of NA may be especially significant when sympathetic activity is enhanced.


Distribution and properties of endo-oligopeptidases A and B in the human neuroendocrine system. The thiol activated endo-oligopeptidases A and B were studied in the soluble fraction of human hypothalamus and various endocrine glands. For the identification, characterization and purification of the enzymes, Z-Gly-Pro-NH-Np and bradykinin were used as substrates. Endo-oligopeptidase B showed a molecular mass ranging from 55.5 to 65.5 kDa and isoelectric point from 4.7 to 4.95. Its activity in tissues was highest in the testis, with intermediate levels in the thyroid, neurohypophysis, adenohypophysis and hypothalamus and the lowest activity in the pineal gland. Endo-oligopeptidase A, 467-fold purified by immunoaffinity chromatography, exhibited a molecular mass of 65.5 kDa in the adenohypophysis but 58.5 kDa in other tissues. The isoelectric point ranged from 5.22 to 5.50. High endo-oligopeptidase A activity was observed in the adenohypophysis, testis and hypothalamus with lesser activity in the neurohypophysis and thyroid and the lowest in the pineal gland. Endo-oligopeptidase A cleaved the bonds Phe-Ser of bradykinin, Met-Arg of BAM-12P and Arg-Arg of neurotensin as described for rabbit brain and heart and bovine brain enzymes. This work shows that endo-oligopeptidase A also hydrolysed the bonds Tyr-Gly of LH-releasing hormone, Pro-Phe of angiotensin I and Tyr-Ile of angiotensin II.


Immunohistochemical localization of 17 alpha-hydroxylase/C17-20 lyase and aromatase cytochrome P-450 in the human ovary during the menstrual cycle. Immunohistochemical localization of 17 alpha-hydroxylase/C17-20 lyase (P-450(17 alpha,lyase)) and aromatase cytochrome P-450 (P-450arom) in normal human ovaries during the menstrual cycle was studied using specific polyclonal antibodies which were raised against corresponding enzymes. In the follicular phase of matured follicles, P-450(17 alpha,lyase) was localized in theca interna cells and P-450arom in granulosa cells. P-450(17 alpha,lyase) was expressed in theca interna cells before P-450arom was expressed in granulosa cells. The corpus luteum showed immunoreactivity to both enzymes and, after menstruation, immunoreactivity decreased gradually until it could not be detected in the corpus albicans. In corpus luteum graviditatis the immunoreactivity continued to be expressed strongly. In some atretic follicles, P-450(17 alpha,lyase) and/or P-450arom continued to be expressed. In the stromal layer, P-450(17 alpha,lyase was detected in secondary interstitial cells, which originated from the theca interna of atretic follicles, and P-450arom was detected in hilar cells. Immunoreactivity to both enzymes was also detected in oocytes of developing follicles. These results are consistent with the two cell theory in the human ovary. They also suggest that androgens and oestrogens are produced not only by follicles and corpora lutea but also by stroma and oocytes.


Retention of normal ovarian function after hysterectomy. What are the long-term effects of hysterectomy on the ovaries of normal women? Ninety-three women aged 29-44 years (median, 38 years) who had undergone hysterectomy for benign reasons 0.3-9.1 years prior to investigation, contributed urine samples twice weekly for a period of 53-149 days (median 102 days) for pregnanediol analysis. The interval between successive pregnanediol peaks and their increment over baseline were measured. The median peak interval was 27.3 days, and 93.3% of all intervals were of 21- to 35-days duration. Of the 337 peaks observed, 96.7% met the criteria previously used to define an ovulatory cycle. These are similar to the figures reported for menstruant women of comparable age. ANOVA showed no significant effect of age or time since hysterectomy on either the interval between peaks or peak increment (P > 0.10 in all cases). The evidence suggests that the ovaries of women who have no uterus behave like those of intact women.


Neural regulation of pupariation in tsetse larvae. A neural mechanism coordinates pupariation behavior and tanning in the tsetse larva. At parturition, the mature larva has already received sufficient ecdysteroid to commit the epidermal cells to metamorphosis but, before sclerotization and tanning of the cuticle can begin, the larva must first select a pupariation site and then proceed through a stereotypic sequence of pupariation behavior that culminates in the formation of a smooth, ovoid puparium. Both pupariation behavior and tanning are inhibited by the central nervous system (CNS) during the wandering phase. This central inhibition is maintained by sensory input originating in the extreme posterior region of the body. At the transition from wandering to pupariation, the posterior signal that induces inhibition of pupariation behavior is removed and the larva begins the contractions associated with pupariation, but the CNS inhibition of tanning persists. At this point, separation of the body into two halves by ligation or nerve transection prevents tanning of the anterior half (containing the CNS), whereas the denervated integument of the posterior half tans completely. Transection of nerves to the midline of the body produces larvae with a tanning pattern that ends abruptly along a sagittal plane, implying that the central control of this process is uncoupled between the left and right regions of the CNS. A few minutes later, when the final shape of the puparium is completed, the CNS inhibition is lifted and the tanning process begins. At this time, separation of the body into two halves by ligation or nerve transection has no inhibitory effects on either part. Exogenous ecdysteroids fail to release the CNS inhibition, and hemolymph containing the pupariation factors from Sarcophaga bullata have no accelerating effects on tsetse pupariation. These results imply that regulation of metamorphosis in the insect integument is not the exclusive domain of blood-borne hormones.


Reversal of interleg coupling in backward locomotion implies a prime role of the direction of locomotion. Conventional descriptions of interleg coupling relate to anatomical definitions such as fore- or hindlegs, right or left legs (i.e. the body is the frame of reference). This convention is obvious for forward walking, where forelegs (in anatomical terms) are also the leading legs (in terms of direction). In backward locomotion, however, the leading legs in terms of direction are the hindlegs in terms of anatomy. What effects do the anatomy and direction of movement have on the sequence of stepping? Our observations on the locomotion of mole rats in a transparent acrylic tunnel revealed that, as in nature, mole rats moved both forwards and backwards. They typically employed a diagonal sequence of steps in forward walking, whereas in backward walking they typically employed a lateral sequence. However, when stepping was described with movement direction as the frame of reference, both forward and backward walking were made up of the same sequence of steps. The same invariant trend was recorded during backward galloping, but to a lesser extent than during walking. We suggest that the backward sequence is simply a reversal of the forward sequence: a hindleg during backward locomotion acts like a foreleg in forward locomotion, while a foreleg acts like a hindleg in forward locomotion. Interleg coupling therefore remains invariant in relation to the direction of locomotion.


Apneic oxygen uptake in the torpid bat, Eptesicus fuscus. Like many mammalian heterotherms, the big brown bat, Eptesicus fuscus, breathes intermittently during torpor. By exploiting this bat's preference to roost in crevices, we could separately measure O2 uptake during ventilatory bouts and apneic periods using a flow-through metabolic chamber with a small dead space volume and short time constant. Oxygen uptake was measured during apneas ranging from 10 to 150 min duration at body temperatures of 20, 10 and 5 degrees C. The fraction of total O2 uptake acquired during apnea was 0.26 +/- 0.03 (9), 0.54 +/- 0.10 (5) and 0.35 +/- 0.04 (3) for body temperatures of 20, 10 and 5 degrees C, respectively. Cardiogenic pulsations during apnea visible on plethysmographic pressure traces and theoretical calculations of airway and cutaneous diffusion potentials support the notion that apneic O2 uptake occurs down an open airway by both diffusion and bulk convection.


Isolation of a neuropeptide from locust corpus cardiacum which influences ileal transport. 1. Schistocerca gregaria ion-transport peptide (Scg-ITP) was isolated from aqueous extracts of the corpus cardiacum by a four-step procedure, utilizing reverse-phase high-performance liquid chromatography for separation and stimulation of a Cl(-)-dependent short-circuit current (Isc) across locust ilea as the bioassay. 2. Scg-ITP has an unblocked N terminus and an apparent relative molecular mass of 7700. Thirty-one residues (of an estimated 65) were identified by sequence analysis. 3. Scg-ITP is structurally related to a crustacean family of neuropeptides which includes the crustacean hyperglycaemic hormones from the shore crab Carcinus maenas and the crayfish Orconectes limosus and moult-inhibiting hormone and vitellogenesis-inhibiting hormone from the lobster Homarus americanus. 4. Scg-ITP has no sequence homology with neuroparsins (Nps). Nps are the only other neuropeptides isolated to date that might regulate reabsorption in an insect hindgut (rectum).


Ultrasonic vocalizations of flying bats monitored by radiotelemetry. Ultrasonic vocalizations of flying bats were effectively monitored with radiotelemetry. We describe a device light enough to be carried by an 11 g bat for periods of up to 1 h. It transmitted signals adequate for fine frequency analysis within a range of approximately 3 m. Telemetry permitted the recording of constant-frequency pulses free from flight-induced Doppler shifts and without time delays. The difference in frequency between telemetered signals and the same signals detected by a remote microphone was used to calculate velocity and Doppler shifts. Pulse emission behavior of Pteronotus parnellii in flight was compared with simulated flight on a pendulum. The data showed significant differences in echo bandwidths, constant-frequency pulse durations and interpulse intervals. In flight, pulses and interpulse intervals tended to be shorter and bats maintained echo frequencies within a significantly narrower band. Phases of echolocation that characterized the approach to a target were clearly evident in flight, but not during pendulum swings. Differences in pulse durations and interpulse intervals may be correlated with the integration of wingbeat, respiration and vocalization. The absence of wing motion in simulated flight changes this integration.


Pathogenic activities of live cells and extracellular products of the fish pathogen Pasteurella piscicida. The pathobiological activities in vivo and in vitro of live cells and extracellular products (ECP) of eleven Pasteurella piscicida strains of different origin were examined. Infectivity trials showed that P. piscicida did not possess strict host specificity since the majority of the isolates were virulent for gilthead seabream, rainbow trout and turbot, with LD50 values ranging between 10(3) and 10(6) live cells. However, none of the strains tested were pathogenic for mice (LD50 > 10(8) cells)). In addition, the ECP were strongly toxic for fish (LD50 ranging from 1.0 to 4.6 micrograms protein per g fish), which clearly demonstrates their important role in the pathogenesis of pasteurellosis. All the ECP samples were cytotoxic for fish and homoiothermic cell lines, possessed notable phospholipase activity and displayed haemolytic activity for sheep, salmon and turbot erythrocytes (but not for trout erythrocytes). However, the production of proteolytic enzymes differed among the P. piscicida strains. Although no strain displayed elastase activity, five isolates (the Japanese and Italian strains) hydrolysed casein and gelatin. All these biological activities in vivo and in vitro were lost after heat treatment (100 degrees C for 10 min). The general enzymic patterns of both live cells and ECP evaluated by the API-ZYM system also revealed some variation among the P. piscicida isolates. Generally, whole cells showed a wider range of enzymic activities than ECP. The results presented here are important for the selection of strains in the development of effective polyvalent pasteurellosis vaccines containing both whole cells and ECP.


Secondary fatty alcohols of Mycobacterium xenopi. Secondary alcohols of Mycobacterium xenopi were studied by gas chromatography and gas chromatography-mass spectrometry. Mycobacterial cells were hydrolysed and the liberated alcohols separated by extraction and analysed both underivatized and as trimethylsilyl, methyl ether- and pentafluorobenzoyl derivatives. Seven straight-chain secondary alcohols containing from 18 to 24 carbon atoms and two branched-chain secondary alcohols with 21 and 23 carbon atoms were present in all of the studied strains.


Succinylated lipid A is a potent and specific inhibitor of endotoxin mitogenicity. Chemically modified lipopolysaccharides of Salmonella abortus-equi were tested for mitogenicity on mouse spleen cells as well as antagonism of the mitogenicity of intact lipopolysaccharide (LPS). All the lipopolysaccharide preparations deacylated by different alkaline treatments suffered a drastic loss of mitogenicity. The mitogenic activity of lipid A was also lost when succinic residues were introduced on hydroxyl groups. Partially deacylated alkaline-treated preparations (but not completely deacylated preparations) inhibited the activation of splenic B-cells by LPS. They were found to be toxic to spleen cells, however, and to suppress not only the mitogenicity of LPS but that of concanavalin A as well. This inhibitory action was not exhibited when all of the fatty acid was eliminated. Succinylated lipid A, on the other hand, was not toxic to the cells and inhibited the B-cell mitogenicity of lipopolysaccharide (but not the T-cell mitogenicity of concanavalin A). Chemical analysis revealed that about 4.6 mol of succinic acid had been introduced into lipid A by succinylation, and that the fatty acid and phosphate composition was unchanged by this treatment. Macrophages do not seem to participate in this inhibition. Inhibition was observed when succinylated lipid A was added either at the same time or after lipid A mitogen, but optimal inhibition was expressed when it was added to the culture 3 h before LPS. Inhibition was not affected by washing the cells before adding LPS. Inhibition increased as the ratio of suppressor to mitogen increased, suggesting that the succinylated lipid A competes with intact LPS.


Glycine betaine transport by Staphylococcus aureus: evidence for two transport systems and for their possible roles in osmoregulation. The transport of glycine betaine by Staphylococcus aureus was investigated. Two transport systems were found that could be differentiated on the basis of their affinity for glycine betaine and their activation by osmotic pressure. The high-affinity system was relatively independent of osmotic pressure and exhibited a Km of approximately 3 microM. This system was not inhibited by proline, for which a separate high-affinity transport system has been recently discovered. The low-affinity system was activated approximately 35-fold by an increase in osmotic pressure and exhibited a Km of approximately 130 microM for glycine betaine. This system is partially inhibited by excess proline and may be identical to the low-affinity system recently described for proline. Both glycine betaine transport systems are Na(+)-dependent.


Structural studies of an emulsion-stabilizing exopolysaccharide produced by an adhesive, hydrophobic Rhodococcus strain. The primary structure of an emulsion-stabilizing exopolysaccharide from the adhesive, hydrophobic Rhodococcus strain No. 33 was elucidated by NMR spectroscopy, methylation analyses, periodate oxidation and oligosaccharide analyses. The polysaccharide PS-33 consisted of rhamnose, galactose, glucose and glucuronic acid in molar ratios of 2:1:1:1. The main chain contained 3-substituted alpha-D-glucuronic acid linked to the 3-position at alpha-L-rhamnose, in addition to 3-substituted residues of beta-D-galactose and alpha-D-glucose. The alpha-L-rhamnose of the side chain was linked to position 4 of the galactose. In addition, the polysaccharide was O-acetylated, corresponding to one acetyl group per repeating unit. From the results two structural possibilities could be suggested. As the polysaccharide carries hydrophobic groups (methyl of rhamnose/O-acetyl), it is very likely that these are of general significance for the emulsifying activity of polysaccharides. It also seems to be possible that this polysaccharide is at least partially responsible for the hydrophobic cell surface properties of the Rhodococcus strain No. 33 and it may be involved in hydrophobic interactions when adhering to hydrophobic interfaces.


Regulation of the secretion of Rhizopus oligosporus extracellular carboxyl proteinase. Secretion of the extracellular Rhizopus carboxyl proteinase (EC 3.4.23.6) by Rhizopus oligosporus is repressed in the presence of low-molecular-mass sources of nitrogen, sulphur and carbon. Proteinase is secreted when the medium is deficient in any one of these three nutrients. In the case of nitrogen metabolite repression, control is at the level of transcription. Induction of proteinase secretion by exogenous protein does not occur in any of the media examined.


Analysis of transcription and translation of glycolytic enzymes in glucose-limited continuous cultures of Saccharomyces cerevisiae. mRNA steady-state levels and activities of enzymes of intermediary carbon metabolism (hexokinase, phosphoglucoisomerase, phosphofructokinase, glucose-6-phosphate dehydrogenase, phosphoglucomutase) and glucose-regulated enzymes (pyruvate decarboxylase, pyruvate dehydrogenase, invertase, alcohol dehydrogenase) were determined in glucose-limited continuous cultures of an industrial strain of Saccharomyces cerevisiae at different dilution rates (D) ranging from 0.05 to 0.315 h-1. The activity of most enzymes measured remained constant over this range except for alcohol dehydrogenase I/II which decreased proportionally with increasing dilution rate. A decrease in phosphoglucomutase activity occurred with increasing dilution rate but reached a minimum at D 0.2 h-1 and from thereon remained constant. A decrease in pyruvate decarboxylase activity and a slight decrease in phosphoglucoisomerase activity was observed. At D 0.29/0.315 h-1, at the onset of the Crabtree effect, most glycolytic enzymes remained constant except for pyruvate decarboxylase and glucose-6-phosphate dehydrogenase which increased at D 0.315 h-1 and alcohol dehydrogenase I/II which decreased. The ADHI/II and PDC1 mRNA levels obtained at the different dilution rates were in accordance with the activity measurements. The mRNA level of HXK1 decreased with increasing dilution rates, whereas the transcription of HXK2 increased. Pyruvate dehydrogenase (PDA1) and PGI1 mRNA fluctuated but no significant change could be detected. These results indicate that there is no transcriptional or translational regulation of glycolytic flux between D 0.05 h-1 and 0.315 h-1 except at the branch point between oxidative and fermentative metabolism (pyruvate decarboxylase/pyruvate dehydrogenase) at D 0.315 h-1. Surprisingly regulation of the Crabtree effect does not seem to involve transcriptional regulation of PDA1.(ABSTRACT TRUNCATED AT 250 WORDS)


A developmental mutation (npfL1) resulting in cell death in Physarum polycephalum. In Physarum, microscopic uninucleate amoebae develop into macroscopic multinucleate plasmodia. In the mutant strain, RA614, plasmodium development is blocked. RA614 carries a recessive mutation (npfL1) in a gene that functions in sexual as well as apogamic development. In npfL+ apogamic development, binucleate cells arise from uninucleate cells by mitosis without cytokinesis at the end of an extended cell cycle. In npfL1 cultures, apogamic development became abnormal at the end of the extended cell cycle. The cells developed a characteristic rounded, vacuolated appearance, nuclear fusion and vigorous cytoplasmic motion occurred, and the cells eventually died. Nuclei were not visible by phase-contrast microscopy in most of the abnormally developing cells, but fluorescence microscopy after DAPI staining revealed intensely staining, condensed nuclei without nucleoli. Studies of tubulin organization during npfL1 development indicated a high frequency of abnormal mitotic spindles and, in some interphase cells, abnormally thick microtubules. Some of these features were observed at low frequency in the parental npfL+ strain and may represent a pathway of cell death, resembling apoptosis, that may be triggered in more than one way. Nuclear fusion occurred during interphase and mitosis in npfL1 cells, and multipolar spindles were also observed. None of these features were observed in npfL+ cells, suggesting that a specific effect of the npfL1 mutation may be an incomplete alteration of nuclear structure from the amoebal to the plasmodial state.


Structure and function of the spoIIIJ gene of Bacillus subtilis: a vegetatively expressed gene that is essential for sigma G activity at an intermediate stage of sporulation. The spo-87 mutation is one of two sporulation mutations originally used to define the spo0J locus of Bacillus subtilis. We now show that it blocks sporulation after completion of prespore engulfment (stage III). Surprisingly, the operon is expressed vegetatively, probably from a sigma A-dependent promoter, and its expression is shut down at the transcriptional level at about the onset of sporulation. DNA sequencing reveals that the locus defined by spo-87, which we now designate spoIIIJ, consists of a bicistronic operon. However, only the first gene is essential for sporulation; the function of the second cistron is cryptic. The predicted SpoIIIJ product has an M(r) of 29,409. It probably forms a lipoprotein and is rich in basic and hydrophobic amino acids. Mutations in spoIIIJ abolish the transcription of prespore-specific genes transcribed by the sigma G form of RNA polymerase but not transcription of the spoIIIG gene encoding sigma G. The SpoIIIJ product could be involved in a signal transduction pathway coupling gene expression in the prespore to events in the mother cell, or it could be necessary for essential metabolic interactions between the two cells.


The use of bacterial luciferase for monitoring the environmental regulation of expression of genes encoding virulence factors in Listeria monocytogenes. A promoter probe vector, which utilized the lux AB genes from Vibrio fischeri as reporters of gene expression, was constructed for use in Listeria monocytogenes. Using this system gene expression can be monitored non-destructively and in real-time, simply by measuring cellular bioluminescence. Derivatives of the promoter probe were constructed that contained the cloned promoters from the hlyA and plcA genes of L. monocytogenes. The activity of these promoters was dependent on the transcriptional activator PrfA. Accordingly, in a strain containing an intact copy of the prfA gene, expression from both the hlyA and plcA promoters was 25-45-fold higher than in prfA mutants. Heat shock was identified as an environmental signal which induced expression of hlyA and plcA. Conversely, oxidative stress had no effect upon the expression of the virulence factors. In addition, the composition of the growth media was found to have a dramatic effect upon the expression of hlyA and plcA, suggesting the presence of an unidentified signal which may regulate induction of expression of virulence genes in L. monocytogenes.


Identification of an outer-membrane haemoglobin-binding protein in Neisseria meningitidis. Although Neisseria meningitidis can use haemoglobin as an iron source in vitro, the mechanism of haemoglobin-iron uptake is unknown. Using a biotinylated human haemoglobin probe in a solid-phase dot-binding assay, haemoglobin-binding activity was detected in total membranes derived from meningococci grown under iron-limited but not iron-sufficient conditions. In competition binding experiments, bovine and human haemoglobin could abrogate binding. In contrast, no binding inhibition was seen with ferric nitrate, protoporphyrin IX, and iron-loaded human transferrin. The ability of both haemin and catalase, a nonhaemoglobin haem-containing compound, to inhibit binding competitively suggested that the ligand recognized by the binding protein is the haem moiety. Scatchard plot analysis revealed a heterogeneous receptor population. Limited proteolysis with proteinase K abolished binding activity, suggesting a haemoglobin-protein interaction. Detection of activity in a whole-cell binding assay demonstrated that this haemin-binding protein was surface exposed. In a limited survey of meningococcal strains, the presence of haemoglobin-binding activity in all isolates indicated that expression of this binding protein is not serogroup specific.


Adhesion to porcine squamous epithelium of saccharide and protein moieties of Lactobacillus fermentum strain 104-S. The mechanism by which Lactobacillus fermentum strain 104-S adheres to porcine squamous epithelium was investigated by studying the adsorption to epithelial cells, and control surfaces, of radioactively labelled material released from the bacterial cells by water extraction. The released material was fractionated by gel filtration and the adsorption of pronase-sensitive and -resistant material in the various fractions to porcine gastric tissue and the control surfaces of polystyrene and immobilized bovine serum albumin (BSA) was determined. The fraction with affinity for the epithelium was characterized by enzymic degradation, periodate oxidation, lipid extraction, and protein and carbohydrate analyses. The adsorption pattern of radioactively labelled crude released material mimicked the adhesion of whole labelled cells to polystyrene and to gastric squamous tissue pieces. On fractionation, the pattern of adsorption to polystyrene and BSA was different from that obtained for the tissue pieces. Considerably less labelled pronase-stable material bound to surfaces of polystyrene and BSA, as compared with the tissue, suggesting that the pronase-resistant component has a tissue-specific affinity. After pronase treatment of the fraction of M(r) about 20,000 (20 K) containing labelled components with affinity for the epithelium, only saccharides were detected. Radioactivity was lost after hydrolysis with HCl, and therefore this pronase-resistant labelled component must be a saccharide. It is concluded that protein moieties in the extract have an affinity for several surfaces, including polystyrene, and that saccharide moieties have a specific affinity for the gastric squamous epithelium.


Purification and characterization of a surface lectin from the nematode-trapping fungus Arthrobotrys oligospora. Several studies have indicated that the capture of nematodes by the nematophagous fungus Arthrobotrys oligospora is mediated by a lectin on the fungal surface. One of the major surface proteins of this fungus showed haemagglutinating activity and was isolated by affinity chromatography using a mucin Sepharose column. Biochemical analysis showed that the protein was a dimeric glycoprotein with a molecular mass of 36 kDa and an isoelectric point of pH 6.5, and contained no sulphur amino acids. The protein was N-terminally blocked; four internal peptides were sequenced, and showed no significant similarity to sequences in the Swiss-Prot or PIR databases. The haemagglutinating activity of the isolated protein was not inhibited by any of the mono- or disaccharides tested, but it was inhibited by the glycoproteins fetuin and mucin. The haemagglutinating activity changed after incubating the protein in buffers of different pH, with maximal activity at pH 11.0 and no activity at pH 2.8. The lectin was tested for different enzymic activities but none were detected. Analysis of the haemagglutinating activity in various cell fractions indicated that the protein was associated with extracellular polymer layers and with the cell wall of the fungus. About the same amount of the haemagglutinating protein was recovered from samples of vegetative mycelium and of mycelium containing nematode-trapping cells.


The periplasmic flagella of Serpulina (Treponema) hyodysenteriae are composed of two sheath proteins and three core proteins. The major components of the periplasmic flagella of the spirochaete Serpulina (Treponema) hyodysenteriae strain C5 were purified and characterized. We demonstrate that the periplasmic flagella are composed of five major proteins (molecular masses 44, 37, 35, 34 and 32 kDa) and present their location, N-terminal amino acid sequence and immunological relationship. The 44 kDa and the 35 kDa protein are on the sheath of the periplasmic flagellum, whereas the 37, 34 and 32 kDa protein reside in the periplasmic flagellar core. The two sheath flagellar proteins are immunologically related but have different N-terminal amino acid sequences. The N-terminus of the 44 kDa protein shows homology with the sheath flagellins of other spirochaetes, but the 35 kDa protein does not. The three core proteins are immunologically cross-reactive and their N-terminal amino acid sequences are almost, but not completely, identical, indicating that the core proteins are encoded by three distinct genes. The core proteins show extensive N-terminal sequence similarities and an immunological relationship with periplasmic flagellar core proteins of other spirochaetes.


Physico-chemical and structural properties of the surfaces of Peptostreptococcus micros and Streptococcus mitis as compared to those of mutans streptococci, Streptococcus sanguis and Streptococcus salivarius. The surface properties of nine Streptococcus mitis and four Peptostreptococcus micros strains from the oral cavity were examined and compared with a large group of oral streptococci. Zeta potential and contact angle measurements were employed to determine physico-chemical cell surface properties. In addition, elemental surface concentration ratios were obtained via X-ray photoelectron spectroscopy, and surface structures were examined with transmission electron microscopy. The S. mitis and P. micros strains were found to have higher isoelectric points, higher hydrophobicities and higher N/C surface concentration ratios than some other oral streptococci. The combined data suggest that both species possess large amounts of surface protein. All the S. mitis strains displayed abundant surface fibrils in negative staining, but the P. micros strains were devoid of surface appendages indicating that surface protein is present in different forms in the two species. The surfaces of S. mitis and P. micros type strains differed significantly from the other strains examined.


Purification and amino acid sequence of sakacin A, a bacteriocin from Lactobacillus sake Lb706. Sakacin A, a bacteriocin produced by Lactobacillus sake Lb706 and which inhibits the growth of Listeria monocytogenes, was purified to homogeneity by ammonium sulphate precipitation and ion-exchange, hydrophobic-interaction and reversed-phase chromatography. The complete amino acid sequence of sakacin A was determined by Edman degradation. The bacteriocin consisted of 41 amino acid residues and had a calculated M(r) of 4308.7, which is in good agreement with the value determined by mass spectrometry. The structural gene encoding sakacin A (sakA) was cloned and sequenced. The gene encoded a primary translation product of 59 amino acid residues which was cleaved between amino acids 18 and 19 to yield the active sakacin A. Sakacin A shared some sequence similarities with other bacteriocins.


A new colicin that adsorbs to outer-membrane protein Tsx but is dependent on the tonB instead of the tolQ membrane transport system. A new colicin, Col5, was synthesized by an Escherichia coli isolate of human origin from the ECOR Collection. It was unique because it adsorbed to the outer-membrane protein Tsx, but used the tonB rather than the tolQ membrane transport system, which is employed by the only other Tsx-specific colicin, ColK. Col5 was encoded by a 5.2 kb plasmid, p5. It was inducible by mitomycin C, and strains harbouring p5 exhibited quasi-lysis. The bactericidal protein had an M(r) of 56,000.


Characterization and purification of mesentericin Y105, an anti-Listeria bacteriocin from Leuconostoc mesenteroides. A Leuconostoc mesenteroides ssp. mesenteroides was isolated from goat's milk on the basis of its ability to inhibit the growth of Listeria monocytogenes. The antimicrobial effect was due to the presence in the culture medium of a compound, named mesentericin Y105, excreted by the Leuconostoc mesenteroides Y105. The compound displayed known features of bacteriocins from lactic acid bacteria. It appeared as a proteinaceous molecule exhibiting a narrow inhibitory spectrum limited to genus Listeria. The apparent relative molecular mass, as indicated by activity detection after SDS-PAGE, was 2.5-3.0 kDa. The bacteriocin was purified to homogeneity by a simple three-step procedure: a crude supernatant obtained from an early-stationary-phase culture in a defined medium was subjected to affinity chromatography on a blue agarose column, followed by ultrafiltration through a 5 kDa cut-off membrane, and finally by reverse-phase HPLC on a C4 column. Microsequencing of the pure bacteriocin and of tryptic fragments showed that mesentericin Y105 is a 36 amino acid polypeptide whose primary structure is close to that of leucocin A-UAL 187, which contains an extra residue at the C-terminus and displays only two differences in the overlapping sequence. However, unlike leucocin A-UAL 187, mesentericin Y105 displayed a bactericidal mode of action.


History of developmental neuroethology: early contributions from ethology. Ethology has its roots in the natural history of animal behavior. Questions of causation and function have historically been complementary, and each has rested upon a prior appreciation of the behavior of animals in nature. It is thus difficult to place a single time or place where ethology was born. Early evolutionary interests hinted at developmental constraints that continue to guide much research. It has only been relatively recently, however, that the explicit analysis of neural mechanisms in behavior has received the attention it deserves in developmental analyses. A mature developmental neuroethology will require a synthesis of the broad insights of ethology with refined neurobiological technique. Fundamental, however, is the primary focus upon behavior as it normally occurs.


Pathways in the emergence of developmental neuroethology: antecedents to current views of neurobehavioral ontogeny. The historical forces that have contributed to our current views of neurobehavioral development (and thus to the fields of developmental psychobiology and neuroethology) are many and varied. Although similar statements might be made about almost any field of science, it is in particular true of this field, which represents a kind of mongrel discipline derived from at least three major sources (psychology, embryology, and neuroscience) and several more minor ones (including developmental psychology and psychiatry, psychoanalysis, education, zoology, ethology, and sociology). Although I attempt to demonstrate here how each of these sources may have influenced the emergence of a unified field of developmental psychobiology or developmental neuroethology, because the present article represents the first attempt of which I am aware to trace the history of these fields I am certain that there is considerable room for improvement, correction, and revision of the views expressed here. Accordingly, I consider this inaugural effort a kind of reconnaissance intended to trace a necessarily imperfect historic path for others to follow and improve upon. In the final analysis, I will be satisfied if this article only serves to underscore two related points: first is the value derived from historical studies of contemporary issues in development, and the second concerns the extent to which our current ideas and concepts about neurobehavioral development, ideas often considered new and contemporary, were already well known to those who came before us. The first point underscores the arguments expressed in the Introduction that the present must always be reconciled with the past, for the past is never entirely past. The second point returns full circle to an important thought expressed in the opening quotation to this article, namely, that even though our historic predecessors lacked much of the empirical facts available to us they were nonetheless able to attain a surprisingly deep understanding of neurobehavioral ontogeny.


Developmental neuroethology of insect metamorphosis. During metamorphosis, the insect nervous system must change to accomodate alterations in body form and behavior. Studies primarily on moths have shown that these changes involve the death of some larval neurons, the conservation and remodeling of others, and the maturation of new, adult-specific cells. The motor and sensory sides of the adult CNS vary in this regard with the former being constructed primarily from remodeled larval components, whereas the latter arises primarily from new neurons. Neuronal remodeling has received considerable attention. Larval-specific dendritic fields are pruned back during the larval-pupal transition, followed by the sprouting of adult-specific dendrites. Simple reflexes have been used to correlate these neuronal changes with the acquisition or loss of particular behaviors. The loss of the proleg retraction reflex is associated with the regression of the dendritic arbors of the proleg motoneurons. By contrast, expansion of axon arbors of the gin-trap afferents is necessary, but not sufficient, for the assembly of the gin-trap reflex in the pupal stage. The stretch receptor reflex provides a third example in which a new dendritic field in the adult form of a neuron is associated with new adult-specific connections. Interestingly, these connections are masked by persisting larval contacts until the emergence of the adult moth. For the metamorphosis of more complex behavioral circuits, some, such as that for flight behavior, seem to be assembled de novo, whereas others, like that for adult ecdysis behavior, show conservation of some circuit elements from the larval stage but with the superposition of some adult-specific components.


Claw asymmetry in lobsters: case study in developmental neuroethology. An enduring debate in the study of development is the relative contribution of genetic and epigenetic factors in the genesis of an organism, that is, the nature vs. nurture debate. The behavior of the paired claws in the lobster offers promising material for pursuing this debate because of the way they develop. The paired claws and their closer muscles are initially symmetrical; both are slender in appearance and have a mixture of fast and slow fibers in their closer muscles. During a critical period of development, they become determined into a major (crusher) and minor (cutter) claw and during subsequent development acquire their final form and behavior: The crusher becomes a stout, molar-toothed claw capable of closing only slowly because its closer muscle has 100% slow fibers while the cutter becomes a slender, incisor-toothed claw capable of closing rapidly because its closer muscle has 90% fast fibers. Our initial hypothesis was that the more active claw became the crusher and its less active counterpart the cutter. Presumably, nerve activity would influence muscle transformation, which in turn would influence the exoskeleton to which they attach and hence claw morphology. Curtailing nerve activity to the claw prevented crusher development, while reflex activation of a claw promoted its development; both results support the notion that nerve activity directly regulates claw form and function. This is not, however, the case, for when both claws were reflexly exercised neither formed a crusher, signifying rather that bilateral differences in predominantly mechanoreceptive input to the paired claws somehow lateralized the claw ganglion [central nervous system (CNS)] into a crusher and cutter side. The side experiencing the greater activity becomes the crusher side while the contralateral side becomes the cutter and is also inhibited from ever becoming a crusher. This initial lateralization in the CNS is expressed, via as yet unknown pathways, at the periphery in claw morphology, muscle composition, and behavior. The critical period defines a time when the CNS is susceptible to being lateralized into a crusher and cutter side. Such lateralization is dependent upon experience of the environment in the form of mechanoreceptive input. In the absence of such experience, the CNS is not lateralized and paired cutter claws develop. Thus, while the critical period for crusher determination is genetically determined the actual trigger is influenced by experience.


Development of the jamming avoidance response and its morphological correlates in the gymnotiform electric fish, Eigenmannia. The electric fish, Eigenmannia, will smoothly shift the frequency of its electric organ discharge away from an interfering electric signal. This shift in frequency is called the jamming avoidance response (JAR). In this article, we analyze the behavioral development of the JAR and the anatomical development of structures critical for the performance of the JAR. The JAR first appears when juvenile Eigenmannia are approximately 1 month old, at a total length of 13-18 mm. We have found that the establishment of much of the sensory periphery and of central connections precedes the onset of the JAR. We describe three aspects of the behavioral development of the JAR: (a) the onset and development of the behavior is closely correlated with size, not age; (b) the magnitude (in Hz) of the JAR increases with size until the juveniles display values within the adult range (10-20 Hz) at a total length of 25-30 mm; and (3) the JAR does not require prior experience or exposure to electrical signals. Raised in total electrical isolation from the egg stage, animals tested at a total length of 25 mm performed a correct JAR when first exposed to the stimulus. We examine the development of anatomical areas important for the performance of the JAR: the peripheral electrosensory system (mechano- and electroreceptors and peripheral nerves); and central electrosensory pathways and nuclei [the electrosensory lateral line lobe (ELL), the lateral lemniscus, the torus semicircularis, and the pace-maker nucleus]. The first recognizable structures in the developing electrosensory system are the peripheral neurites of the anterior lateral line nerve. The afferent nerves are established by day 2, which is prior to the formation of receptors in the epidermis. Thus, the neurites wait for their targets. This sequence of events suggests that receptor formation may be induced by innervation of primordial cells within the epidermis. Mechanoreceptors are first formed between day 3 and 4, while electroreceptors are first formed on day 7. Electroreceptor multiplication is observed for the first time at an age of 25 days and correlates with the onset of the JAR. The somata of the anterior lateral line nerve ganglion project afferents out to peripheral electroreceptors and also send axons centrally into the ELL. The first electroreceptive axons invade the ELL by day 6, and presumably a rough somatotopic organization and segmentation within the ELL may arise as early as day 7. Axonal projections from the ELL to the torus develop after day 18.(ABSTRACT TRUNCATED AT 400 WORDS)


Development of anuran locomotion: ethological and neurophysiological considerations. There are dramatic quantitative and qualitative differences in the locomotor behavior of larval and juvenile frogs. Larvae (tadpoles) are primarily herbivourous and rely heavily on locomotion via undulations to acquire food and avoid predation. After metamorphosis, juvenile frogs adopt a carnivorous lifestyle and capture prey and avoid predators by remaining motionless in a place of concealment. When they must move, frogs locomote by means of ballistic hops or by more conventional walking. However, locomotion of both tadpoles and frogs can be considered of two fundamental functional types: (a) startle and escape; and (b) sustained locomotion. Neural mechanisms underlying startle responses and sustained locomotion in larvae and juveniles are described and possible ontogenetic relationships those behaviors are proposed. The role of different parts of the nervous system in the ontogeny of locomotion, as well as nonneuronal factors, are described. Results show that the transition from tadpole-like behavior to frog-like behavior is not a simple function of maturation of central locomotor controls. Rather, it results from a complex interaction of central nervous system maturation, morphological change, and a change in habitat preference. Examples of similar multidimensional control of behavioral ontogeny in other species are described, and it is argued that to understand the ontogeny of behavior, one must investigate contributions made at all levels, from the neuronal to the environmental.


Neuroethological approaches to the study of motor development in chicks: achievements and challenges. Chicks and chick embryos provide a useful model system for the study of issues related to the development of motor behaviors. EMG and kinematic analyses of leg movements have been used to provide new data on the organization of embryonic motility. These data suggest that the circuitry needed to produce a basic, coordinated motor pattern is available early in development. This circuitry then appears to be retained throughout life. Evidence from analysis of EMG patterns and leg deafferentation studies suggest that the output of this basic circuit can be modulated by sensory input to produce the motor patterns of later behaviors, such as hatching and walking. If the same circuitry is present throughout life, then mechanisms for initiation and termination of particular behaviors must be available to ensure that specific behaviors are turned on and off at appropriate times. For example, hatching can be turned on by a specific sensory signal: proprioceptive signals from the bent neck. In addition to reviewing current research on the development of chick motor behaviors, methodological considerations and suggestions for future research are presented.


Developmental plasticity in neural circuits controlling birdsong: sexual differentiation and the neural basis of learning. In many species of passerine songbirds, males learn their song during defined periods of life. Female song is often reduced or absent, as are the brain regions controlling song. Sexual differences in the brain arise because of the action of sex steroids, which trigger the formation of some neural pathways (especially the pathway from the higher vocal center to the robust nucleus) and prevent the atrophy of others in males. These neural changes occur during periods of developmental song learning and can recur during periods of learning in adult birds. The process of learning is correlated with major increases or decreases in the numbers of neurons in specific neuronal populations, suggesting that the formation or loss of specific neural pathways regulates the ability to learn. Species differences in sexual differentiation and learning allow informative cross-species comparisons of neural structure and behavior.


Emergence of pattern in the development of mammalian movement sequences. The manner in which behavior is patterned in space and over time represents a fundamental problem in both ethology and neuroscience. Prior to the analysis of mechanism it is important to be sensitive to issues involved in the provision of descriptive taxonomies. Often alternative modes of description lead to different perspectives and research strategies. In both the development of behavioral patterns and their expression a major question is how underlying organizational systems become self-organizing through the process of mutual interactions. It is clear that simple static dichotomies in both behavioral and developmental science must be replaced by more sophisticated models that emphasize the dynamics of pattern formation and control. Some of these perspectives are illustrated from our ongoing research on rodent movement patterns.


Neuroethology of olfactory preference development. Young mammals come to approach the odor of their mother, a response that facilitates their survival during early life. Young rats induce a cascade of events in their mother to induce the emission of her odor. The pups increase circulating prolactin levels, which increases food intake and the emission of large quantities of cecotrophe containing the maternal odor. This odor is synthesized by the action of cecal microorganisms and changes with maternal diet. The diet-dependence of the odor requires the pups to acquire their attraction to the odor postnatally. The acquisition of this preference occurs when an odor is paired with the tactile stimulation that pups receive during maternal care. The action of the tactile stimulation appears to be mediated by noradrenaline. The development of this type of olfactory attraction is accompanied by changes in the regions of the olfactory bulb that are responsive to the attractive odor. Metabolic, anatomical, and neurophysiological changes in response to the attractive odor emerge in such regions of the bulb after early olfactory preference training.