Connections between the retrosplenial cortex and the hippocampal formation in the rat: a review. The retrosplenial cortex is situated at the crossroads between the hippocampal formation and many areas of the neocortex, but few studies have examined the connections between the hippocampal formation and the retrosplenial cortex in detail. Each subdivision of the retrosplenial cortex projects to a discrete terminal field in the hippocampal formation. The retrosplenial dysgranular cortex (Rdg) projects to the postsubiculum, caudal parts of parasubiculum, caudal and lateral parts of the entorhinal cortex, and the perirhinal cortex. The retrosplenial granular b cortex (Rgb) projects only to the postsubiculum, but the retrosplenial granular a cortex (Rga) projects to the postsubiculu, rostral presubiculum, parasubiculum, and caudal medial entorhinal cortex. Reciprocating projections from the hippocampal formation to Rdg originate in septal parts of CA1, postsubiculum, and caudal parts of the entorhinal cortex, but these are only sparse projections. In contrast, Rgb and Rga receive dense projections from the hippocampal formation. The hippocampal projection to Rgb originates in area CA1, dorsal (septal) subiculum, and post-subiculum. Conversely, Rga is innervated by ventral (temporal) subiculum and postsubiculum. Further, the connections between the retrosplenial cortex and the hippocampal formation are topographically organized. Rostral retrosplenial cortex is connected primarily to the septal (rostrodorsal) hippocampal formation, while caudal parts of the retrosplenial cortex are connected with temporal (caudoventral) areas of the hippocampal formation. Together, the elaborate connections between the retrosplenial cortex and the hippocampal formation suggest that this projection provides an important pathway by which the hippocampus affects learning, memory, and emotional behavior.


Evidence for NMDA receptor involvement in environmentally induced dentate gyrus plasticity. Research has demonstrated environmentally induced plasticity of hippocampal dentate gyrus-evoked potentials. Other research has shown a role of the NMDA receptor in dentate gyrus long-term potentiation (LTP). The authors tested the role of the NMDA receptor in one form of environmentally induced plasticity, in which transferring animals from their home cages to another environment results in significant excitatory postsynaptic potential (EPSP) enhancement and concomitant depression of the population spike. Rats were chronically implanted with stimulating electrodes in the perforant path and recording electrodes in the dentate gyrus bilaterally. Evoked potentials were recorded from freely behaving rats for four 20-minute sessions (1/wk), which took place immediately following an environmental transfer. Rats received 0.00, 0.05, 0.08, or 0.10 mg/kg MK-801 s.c. 30 minutes prior to recording sessions in either an ascending- or descending-dose series. Results showed that MK-801 produced a reduction of the EPSP enhancement, which takes place over the 20-minute session. The effects of MK-801 on spike depression varied as a function of dose series and time within a session, suggesting a long-term effect of MK-801 on spike depression. There was no detected effect of MK-801 on behavior. Results suggest a role of the NMDA receptor in this form of environmentally induced plasticity with different effects of NMDA receptor antagonism on EPSP enhancement and spike depression.


Linear relationship between the maintenance of hippocampal long-term potentiation and retention of an associative memory. The hypothesis that the maintenance or decay of an associative memory trace after an extended retention interval is a function of the residual strength of the synapses originally strengthened during learning was examined in a classical conditioning paradigm in which high-frequency stimulation of a hippocampal input--the medial perforant path--served as a conditioned stimulus. Rats received perforant path stimulus-foot shock pairings while engaged in a previously acquired food-motivated lever-pressing task. Conditioned suppression of lever pressing was the behavioral measure of learning and retention of the association. Stimulus trains to the perforant path at an intensity above the threshold for eliciting a population spike induced long-term potentiation of synaptic transmission in the dentate gyrus. Synaptic potentials recorded extracellularly in the dentate gyrus were subsequently monitored for 31 days to examine quantitatively the decay of synaptic potentiation, a period after which retention of the learned association was assessed. All rats learned the association to a similar extent and displayed equivalent amounts of long-term potentiation by the end of conditioning. A slowly decaying function of synaptic potentiation was observed in remembering rats, i.e., rats with high retention performance after the 31-day learning-to-retention interval, while forgetting was associated with a rapid decay of long-term potentiation. Behavioral performance at the long-term memory test was linearly correlated with the amplitude of long-term potentiation maintained just prior to the retention test. The results favor the hypothesis that long-term associative memory depends, at least in part, on the maintenance of elevated synaptic strengths in the pathway activated during learning and suggest a role for the lasting component of long-term potentiation in the maintenance of memory.


Bilateral knife cuts to the perforant path disrupt spatial learning in the Morris water maze. Both the hippocampus and the entorhinal cortex are known to be crucial for spatial learning, but the contribution of the pathway linking the two structures, the perforant path (PP), has never been tested in a spatial learning paradigm. The present study examined the role of the PP in spatial learning using the Morris water maze. Seven days after bilateral transection of the PP with a fine-bladed knife, rats were habituated to the pool, then trained to swim from varying start locations to a platform submerged in a fixed location. After 28 training trials over 5 days, probe trials (without any platform present) were given to assess spatial memory for the location. Compared to sham-operated controls, lesioned rats showed slower learning and poorer asymptotic performance in terms of both swim path distance and escape latency, and less preference for the correct quadrant during probe trials. When the platform location was "reversed" to the opposite quadrant, the lesioned rats again showed poorer learning, poorer asymptotic performance, and reduced preference for the correct quadrant on the probe trial. When tested with a visible platform whose position varied from trial to trial, lesioned rats performed as well as controls. These results are congruent with previous analyses of the contributions of the entorhinal cortex and hippocampus to spatial learning and suggest that for spatial learning, the PP is a critical functional link between these two structures.


Preserved configural learning and spatial learning impairment in rats with hippocampal damage. This study was undertaken to compare the effect of hippocampal neurotoxic lesions in rats on two behavioral tasks, one a test of spatial learning, and the other an operant discrimination task that is acquired by forming nonspatial configural associations. Lesions of the hippocampus were made with microinjections of ibotenic acid. After postoperative recovery, rats were trained initially to locate a camouflaged escape platform in a water maze using distal spatial cues. Rats also were trained in the maze apparatus with a visible escape platform under conditions in which spatial information was made irrelevant to performance, i.e., cue learning. In an operant task, the same rats were then trained on a discrimination that included simultaneous feature positive and feature negative components (trial types XA+, A-, XB-, B+). After completion of this nonspatial configural learning task, rats received additional training in the water maze using a new platform location for spatial learning. To the extent that proficient performance in both the maze and operant tasks depends on a common function of the hippocampus, i.e., configural learning, the expectation was that hippocampal lesions would prove equally detrimental to performance in both tasks. Contrary to this expectation, lesioned rats were severely impaired in spatial learning but readily acquired the operant discrimination, even exhibiting some evidence of enhanced performance on this nonspatial configural learning task. Performance of the lesioned rats during cue training in the water maze was also enhanced relative to the control group.(ABSTRACT TRUNCATED AT 250 WORDS)


Ultrastructural localization of neuropeptide Y-like immunoreactivity in the rat hippocampal formation. Neuropeptide Y (NPY) has been implicated in the modulation of hippocampal neuronal activity and in the pathophysiology of several neurological disorders involving the hippocampal formation. Thus, this study examines the light and electron microscopic immunoperoxidase labeling of a rabbit polyclonal antibody against porcine NPY in single sections through each lamina of the CA1 and CA3 regions of the hippocampus and the dentate gyrus (DG) of normal adult rats. By light microscopy, the majority of perikarya with intense NPY-like immunoreactivity (NPY-LI) were located in stratum oriens of CA1 and CA3 of the hippocampus and in the hilus of the DG. Fine varicose processes with NPY-LI were found in all layers of the hippocampal formation, but were densest in the outer third of the molecular layer of the DG. The density of NPY-labeling was greater in the ventral portion of the hippocampal formation. By electron microscopy, most NPY-containing perikarya in all three hippocampal regions were: small (8-12 microns) or medium-sized (12-18 microns) and elongated; or medium-sized and round. A dense accumulation of NPY-LI was commonly observed within the individual saccules of Golgi complexes and some rough endoplasmic reticulum in the cytoplasm. Perikarya and dendrites with NPY-LI usually were directly apposed to other neuronal processes (mostly terminals) and lacked astrocytic appositions. The majority of terminals in contact with NPY immunoreactive neurons were unlabeled and synapsed with the shafts of large and small dendrites. In CA1 and CA3 of the hippocampus, the types of synapses formed by the unlabeled terminals were not significantly different; however, more asymmetric synapses than symmetric synapses were formed by the unlabeled terminals on the shafts of small NPY-labeled dendrites in the DG. The terminals with NPY-LI (0.25-1.2 microns) contained many small, clear vesicles and 0-2 large, dense-core vesicles. The types of synapses (i.e., asymmetric and symmetric) and distribution of NPY-labeled terminals on the targets were remarkably similar in each lamina of the hippocampal subregions. The NPY-labeled terminals usually synapsed with one unlabeled perikaryon or dendrite. However, others synapsed either (1) with two unlabeled perikarya or dendrites simultaneously or (2) with one NPY-containing perikaryon or dendrite. Most of the terminals with NPY-LI formed symmetric junctions with the shafts of small (distal) dendrites.(ABSTRACT TRUNCATED AT 400 WORDS)


Postnatal development of mossy cells in the human dentate gyrus: a light microscopic Golgi study. Mossy cells in the human dentate gyrus of adults and children of different ages were impregnated using the rapid-Golgi method. In every case the cause of death was verified by autopsy and the brains were used when neither the history of the patient nor autopsy revealed brain-related disease. Mossy cells in the human share common light microscopic features with the same cell type in rats and monkeys. Their most characteristic feature is the extremely large and complex excrescences on their proximal dendrites. Distal dendrites display pedunculate spines. Mossy cells have a few somal spines. The axon of mossy cells originates from the cell body and gives rise to several collaterals in the hilar region. The axons could be followed for several hundred microns, but in only one case did an axon collateral enter the granule cell layer of the adult dentate gyrus. In the newborn child, mossy cells display immature somal and dendritic features. The soma frequently bear spines. The dendrites are varicose and terminate in presumed growth cones. Both proximal and distal portions of the dendrites bear a few pedunculate spines and long-irregular filopodia. A few small excrescences are present on the proximal dendrites. The first large, complex excrescences on the proximal dendrites of mossy cells appeared in the 7-month-old child. Both somata and dendrites display adult-like characteristics in mossy cells from a 5-year-old child. However, not all mossy cells are alike and some dendrites still display long filopodia. The axons of immature mossy cells were similar to adults. The present results indicate that connections between granule cells and hilar mossy cells of the human dentate gyrus develop through an extended postnatal period of time that may last until the fifth year.


Time course and distribution of neuronal degeneration in the dentate gyrus of rat after adrenalectomy: a silver impregnation study. Recently, Sloviter et al. reported that adrenalectomy (ADX) of young adult rats after 3 months led to a selective loss of granule neurons in the dentate gyrus (DG) and that this loss could be prevented by low doses of corticosterone. In the present study, the ADX-induced neuronal degeneration was investigated in Wistar rats, using a silver impregnation method for degenerating neurons. To examine the time course and distribution of the ADX-induced degeneration, young adult male rats were allowed to survive 2, 3, and 5 days and 1, 2, and 3 weeks after ADX. Argyrophilic neurons were present in the dentate granule cell layer on the second day following ADX. Three days after ADX, the number of argyrophilic granule neurons was much more abundant, and it increased gradually with longer post-ADX survival times. Argyrophilia was specifically confined to dentate granule cells and was accompanied by the occurrence of pyknotic nuclei as observed in adjacent cresyl violet-stained sections. There were significant differences between individual rats in quantity of argyrophilia. About one fifth of the ADX rats showed sporadic or no argyrophilia, in spite of plasma corticosterone levels below the detection limit (10 ng/mL). Sham-operated rats and ADX rats receiving corticosterone (10 mg/L) or dexamethasone (15 mg/L) in their drinking water did not display any argyrophilic neurons in the dentate gyrus. The distribution of the argyrophilia within the DG was highly characteristic with the highest number of degenerating cells in the hidden blade of the middle and the temporal thirds of the DG.(ABSTRACT TRUNCATED AT 250 WORDS)


Intact verbal and nonverbal short-term memory following damage to the human hippocampus. Short-term memory was assessed in two groups of amnesic patients. Six patients had confirmed or suspected damage to the hippocampal formation, and six patients had diencephalic damage as a result of alcoholic Korsakoff's syndrome. Verbal short-term memory was evaluated with seven separate administrations of the standard digit span test in order to obtain a precise measure of short-term memory. Nonverbal short-term memory was evaluated with four tests that assessed apprehension, retention, and the ability to manipulate nonverbal material--all within the span of immediate memory. One of these four tests assessed short-term memory for spatial location. Patients with damage to the hippocampal formation had a digit span equivalent to that of control subjects and also performed normally on the four tests of nonverbal short-term memory. The patients with Korsakoff's syndrome had a marginally low digit span and performed poorly on three of the four nonverbal tasks, a finding consistent with the deficits in attention and visuospatial processing previously described for this patient group. These deficits are likely due to the frontal lobe atrophy typically associated with Korsakoff's syndrome, rather than to diencephalic damage. The results support the view that short-term (immediate) memory, including short-term spatial memory, is independent of the hippocampus.


Navigation by fragment fitting: a theory of hippocampal function. This paper describes a computational theory of spatial learning and navigation and its possible realization in the hippocampus. In the theory, mammals store memories of their geographical environment as a large number of independent fragments. A typical fragment denotes a few prominent landmarks in some region, their geometric relations, and their nongeometric properties, such as smells and visual cues. Navigation involves piecing together current sense data and relevant fragments to form a local map of the animal's surroundings; this is like solving a jigsaw puzzle. This computational model has been implemented in a computer program, whose performance is broadly consistent with observed levels of animal performance, and laboratory results, in spatial learning. Possible realizations of the model in animal brains are discussed. Unlike some neural net models of spatial learning, the model is strongly geometric, and uses special neural structures to store and manipulate two-dimensional vectors and bearings. A possible neural architecture is described in which the hippocampus performs the geometric operations; this has a long-term memory for fragments (somewhere in the neocortex), which can associatively recall fragments into a number of parallel fragment fitters, in the dentate gyrus and CA3 regions. These vary the positions and orientations of their fragments, to optimize the fit of the fragments to each other and to the animal's recent sense data. A local map of the animal's surroundings is stored in CA1 and subicular regions, where matching of fragment positions and attributes takes place. Mismatches are passed back via the entorhinal cortex to improve the fit during the next hippocampal theta cycle. The model offers the potential for understanding current data on spatial learning, on the neuroanatomy of the hippocampus and on place cells in a coherent framework, as well as understanding the role of the hippocampus in nonpositional memory tasks. Comparisons with experimental data are given.


Computational constraints suggest the need for two distinct input systems to the hippocampal CA3 network. The CA3 network in the hippocampus may operate as an autoassociator, in which declarative memories, known to be dependent on hippocampal processing, could be stored, and subsequently retrieved, using modifiable synaptic efficacies in the CA3 recurrent collateral system. On the basis of this hypothesis, the authors explore the computational relevance of the extrinsic afferents to the CA3 network. A quantitative statistical analysis of the information that may be relayed by such afferent connections reveals the need for two distinct systems of input synapses. The synapses of the first system need to be strong (but not associatively modifiable) in order to force, during learning, the CA3 cells into a pattern of activity relatively independent of any inputs being received from the recurrent collaterals, and which thus reflects sizable amounts of new information. It is proposed that the mossy fiber system performs this function. A second system, with a large number of associatively modifiable synapses on each receiving cell, is needed in order to relay a signal specific enough to initiate the retrieval process. This may be identified, we propose, with the perforant path input to CA3.


Comparison of the effects of ethanol and chlordiazepoxide on electrophysiological activity in the fascia dentata and hippocampus regio superior. Acute intoxicating doses of ethanol-producing blood alcohol levels of 120-200 mg% increase paired-pulse (PP) inhibition in the dentate gyrus of anesthetized rats suggesting that ethanol increases recurrent inhibitory processes (Wiesner, J.B., and S.J. Henriksen (1987) Ethanol enhances recurrent inhibition in the dentate gyrus of the hippocampus. Neurosci. Lett. 79:169-173). To further understanding of the neuronal mechanisms underlying this phenomenon, the authors studied the effects of the benzodiazepine (BZ), chlordiazepoxide, and acute intoxicating levels of ethanol on extracellular field potential recordings and single-unit activity in the dentate gyrus and area CA1 of the hippocampus. In the dentate, ethanol had no effect on population excitatory postsynaptic potential (pEPSP) amplitudes or slopes; decreased population spike (PS) amplitudes (25%); increased PP inhibition; decreased dentate granule cell (DGC) spontaneous activity (58%); had no effect on putative interneuron spontaneous activity; and markedly increased post field potential-evoked interneuron discharges (IDs, 218%). Chlordiazepoxide had no effect on pEPSP amplitudes or slopes or PS amplitudes; increased PP inhibition; decreased DGC (62%) and interneuron (72%) spontaneous activity; and markedly decreased IDs (89%). In CA1, ethanol had no effect on pEPSP amplitudes or slopes; decreased PS amplitudes (26%); had no effect on PP responses; decreased pyramidal cell (PC) spontaneous activity (39%); had no effect on interneuron spontaneous activity; and markedly increased IDs (97%). Chlordiazepoxide had no effect on pEPSP amplitudes or slopes or PS amplitudes; had no effect on PP responses; decreased PC spontaneous activity (41%); and had no effect on interneuron spontaneous activity or IDs. The results suggest that the BZs decrease principal cell excitability by postsynaptic facilitation of inhibitory processes, whereas ethanol decreases principal cell excitability indirectly by increasing the excitability of inhibitory interneurons.


Fast (beta) rhythms in the hippocampus: a review. Spontaneous or evoked brain activity in the hippocampus showed a 20-70 Hz beta rhythm under some conditions, typically during behavioral activation and accompanied by a theta rhythm. Beta rhythms are generated locally, perhaps by a recurrent feedback loop involving pyramidal cells and inhibitory interneurons. Modulation of the local circuit and rhythm by cholinergic inputs has also been demonstrated. Under some behavioral states, neural impulses modulated at the beta frequency may transmit preferentially through the trisynaptic circuit in the hippocampus. It is suggested that the beta rhythm may serve to establish transient physiological connections, reflected in coherence at the beta frequency, among neurons in the hippocampus and related structures. Thus, the beta rhythm may play an essential role in hippocampal function.


The importance of comparative studies and ecological validity for understanding hippocampal structure and cognitive function. Building from the premise that hippocampal cognitive function has been molded by natural selection under natural environmental conditions, it is argued that traditional laboratory studies likely do not reveal the richness and complexity of hippocampal function. Research on the role of the hippocampal formation in the navigational behavior of homing pigeons is offered as an example to illustrate the advantages of using an ecological approach to understand hippocampal function. It is further proposed that dissimilarities in hippocampal anatomy, physiology, and neurochemistry found between species reflect species differences in the range of functions served by the hippocampal formation, as well as possibly the molecular and cellular mechanisms that support such functions. These differences notwithstanding, it is suggested that, from an evolutionary perspective, the primary function of the hippocampal formation is a role in some aspect of spatial cognition. Dissimilarities in hippocampal structure and function among extant species are viewed as resulting from differences in evolutionary selective pressure and evolutionary history.


The mechanism of cerebral hypoxic-ischemic damage. The four most prominent hypotheses on the cellular processes leading to hypoxic-ischemic neuronal damage or death are (1) the lactacidosis hypothesis, (2) the calcium overload hypothesis, (3) the excitotoxic hypothesis, and (4) the oxygen-free radical hypothesis. The authors comment on the evidence in favor of and against each in an attempt to select the one hypothesis that best explains the mechanism of cerebral hypoxic-ischemic damage while withstanding the scrutiny of scientific testing. A major part of this inquiry is derived from in vitro studies that are suited to mechanistic exploration. They conclude that the calcium overload hypothesis is the best qualified in this respect. It is important to note, however, that some of the other hypothetical mechanisms may play a secondary role in exacerbating neuronal damage by accelerating calcium influx and overload.


Morphological evidence for altered synaptic organization and structure in the hippocampal formation of seizure-sensitive gerbils. Seizure-sensitive (SS) and seizure-resistant (SR) Mongolian gerbils were used for three experiments. In the first experiment, GABAergic neurons and terminals in the dentate gyrus were localized with GAD immunocytochemistry. GAD-positive puncta adjacent to cell bodies of GABAergic pyramidal basket cells were counted in light microscopic preparations. The pyramidal basket cells of SS gerbils displayed a significant threefold increase in the number of GAD-positive puncta associated with their cell bodies as compared to those from SR gerbils. These data indicate that the number of GABAergic synapses with pyramidal basket cell bodies in the dentate gyrus was greater in SS gerbils. An electron microscopic (EM) analysis of GAD immunocytochemical preparations showed GAD-positive axon terminals forming symmetric synapses with GAD-positive basket cell bodies. However, numerous terminals forming symmetric axosomatic synapses with basket cells were not immunopositive, and other synapses formed by terminals were not classified because reaction product in the cell bodies obscured postsynaptic densities. Therefore, routine EM preparations were analyzed for symmetric and asymmetric axosomatic synapses on pyramidal basket cells and granule cells of SS and SR gerbils. The data obtained from these preparations showed that the pyramidal basket cells of SS gerbils had a selective increase in the number of symmetric synapses per 10 microns of soma as compared to those of the SR gerbils. In contrast, the granule cells did not show any significant difference in the number of either symmetric or asymmetric axosomatic synapses between SS and SR gerbils. These results indicate that pyramidal basket cell bodies of SS gerbils have more inhibitory synapses than do those of SR gerbils. The third experiment used SS gerbils with lesions of the perforant pathway that stopped seizure activity (Ribak, C. E., and S. U. Khan (1987) The effects of knife cuts of hippocampal pathways on epileptic activity in the seizure-sensitive gerbil. Brain Res. 418:251-260). The percentage of axon terminal area occupied by synaptic vesicles and their packing density was determined in CA3 mossy fiber boutons and compared for lesioned and nonlesioned SS gerbils. The mossy fibers of nonlesioned SS gerbils showed a depletion of synaptic vesicles consistent with the previous results of Peterson et al. (Peterson, G. M., C. E. Ribak, and W. H. Oertel (1985) A regional increase in the number of hippocampal GABAergic neurons and terminals in the seizure-sensitive gerbil. Brain Res. 340:384-389).(ABSTRACT TRUNCATED AT 400 WORDS)


Autoradiographic localization of proline uptake in excitatory hippocampal pathways. An autoradiographic method was developed to localize sites of high-affinity, Na(+)-dependent proline uptake in the rat hippocampal formation. Hippocampal slices were incubated with [3H]proline, fixed with a glutaraldehyde/carbodiimide mixture, and cut into frozen sections. The sections were coated with photographic emulsion and autoradiograms were prepared. Autoradiographic grain densities were highest over the inner and outer thirds of the dentate molecular layer, followed by stratum lacunosum-moleculare of area CA3. Stratum oriens and stratum radiatum of area CA1 and CA3 were fairly intensely labeled. The pyramidal and granule cell body layers, stratum lucidum of area CA3, and middle third of the dentate molecular layer were lightly labeled. Effects of surgical and kainic acid lesions suggested that the lateral perforant path, associational-commissural fibers in the fascia dentata, and Schaffer collateral-commissural-ipsilateral stratum oriens fibers have considerable proline uptake capacity. In contrast, the medial perforant path and the mossy fibers appear to accumulate little or no proline. These results suggest that high-affinity, Na(+)-dependent uptake of proline is expressed by a subset of hippocampal glutamate pathways. The relative capacities of glutamate terminal populations to transport glutamate and proline varies widely. Proline was previously shown to possess neuroexcitatory and excitotoxic properties in the rat hippocampal formation. Taken together, these findings argue that proline plays a role in excitatory transmission. In elucidating this role, comparisons between medial and lateral divisions of the perforant path may prove especially advantageous.


Monkey hippocampal neuron responses to complex sensory stimulation during object discrimination. The purpose of this study was to investigate, during the performance of an object discrimination task, responses of neurons in the monkey hippocampal formation to the sight of several objects that have biological meaning, and compare these responses with those of amygdalar neurons studied previously using the same task. Neuronal activity in the hippocampal formation of conscious monkeys was recorded during performance of a task that led to presentation of familiar rewarding, familiar aversive, or unfamiliar objects. Of 864 neurons recorded in the hippocampal formation and adjacent cortices, 160 (18.5%) responded to the sight of a certain object(s). Responses to the sight of different kinds of objects were analyzed in detail. Nondifferential neurons (n = 73) responded to different objects with no significant difference in response magnitudes, and differential neurons (n = 87) responded to different objects with different response magnitudes. Of the differential neurons, 23 responded more strongly to rewarding objects than to other objects (rewarding-object-dominant neurons), but the magnitude of responses to objects did not necessarily correlates with the order of preferences to the objects as determined from observation of animal behavior. Aversive-object-dominant neurons (n = 13) responded more to aversive objects than to other objects. Unfamiliar-object-dominant neurons (n = 7) responded more to unfamiliar objects than to familiar objects. Selective neurons (n = 10) responded selectively to only one object or one category of objects. Fourteen of the rewarding- or averse-object-dominant neurons were tested in extinction or reversal trials. In 12 of 14 neurons, responses to a rewarding or aversive object did not change, or slightly weakened, in extinction or reversal trials. The results suggest the following. (1) Responses of rewarding- or aversive-object-dominant neurons may be involved in object-reward or object-aversion association. However, responses of many of these neurons might reflect past inputs to reinforcement rather than extant emotional processing. (2) Responses of unfamiliar-object-dominant neurons may be involved in recognition of objects based on their familiar or unfamiliar aspects. These results are further discussed and compared with responsiveness of amygdalar neurons.


Spatial responsiveness of monkey hippocampal neurons to various visual and auditory stimuli. To investigate involvement of the hippocampal formation in spatial information processing, activity of neurons in the hippocampal formation of the conscious monkey was recorded during presentation of various visual and auditory stimuli from several directions around the monkey. Of 1,047 neurons recorded, 106 (10.1%) responded to some stimuli from one or more directions. Of these 106 neurons with directionally differentiating responsiveness, 49 responded to visual stimulation, 35 to auditory stimulation, and 22 to both. Among 81 neurons, each tested with more than 10 different stimuli, one type responded independent of the nature of the stimulus (nonselective, n = 39), and responses of the other type depended on the nature of the stimulus (selective, n = 42). To investigate effects of change in spatial relations between test stimuli and background stimuli fixed on the monkey or fixed in the environment, 59 of 106 neurons were tested while the experimental apparatus holding the stimulus was moved relative to the monkey. Of these 59 neurons, 36 changed their responsiveness; 7 maintained the magnitude of their responses but changed the response direction with the movement of the apparatus, 5 changed direction regardless of the movement, and 24 did not change direction, but decreased or extinguished responses from the preferred direction. Thirty-two of 106 neurons were also tested by rotating the monkey. The directionally differentiating responsiveness of 11 neurons followed the monkey (egocentric neurons), that of 9 remained in place in the environment (allocentric neurons), and responses of 12 were reversibly extinguished when the monkey was rotated. The results suggest that these hippocampal neurons may be involved in identification of relations among various kinds of stimuli in different spatial frameworks (egocentric or allocentric) and this identification may be developed from multiple sensory modalities.


Neuronal activity in the hippocampus during delayed non-match to sample performance in rats: evidence for hippocampal processing in recognition memory. Neuronal activity in the CA1 of rats was explored with regard to functional correlates of performance in an odor-guided continuous delayed non-match to sample task. Although different CA1 cells fired in association with each identifiable trial event, these analyses focused on cells that fired selectively during the period of odor cue sampling and response generation. The firing patterns of many of these cells reflected the match or non-match comparison between current and previous odor cues independent of the particular stimuli that composed those comparisons. Such cells were more prevalent in sessions when performance was highly accurate. Hippocampal cells did not demonstrate stimulus-evoked firing that persisted through the memory delay, nor did they fire differentially to session-novel vs. repeated odor presentations. These results suggest that the hippocampus contributes to recognition memory by processing comparisons between current information and representations of previous stimuli stored in parahippocampal and neocortical structures.


Development of synapsin I and synapsin II in intraocular hippocampal transplants. Previous studies have indicated that the appearance of synaptic vesicle-associated proteins known as the synapsins is one indicator of synapse formation. In this study, the levels and morphological distribution of synapsin I and synapsin IIa and IIb were studied in intraocular hippocampal transplants and in situ in the intact hippocampus. No detectable levels of either synapsin I or synapsin II were found in the fetal brain. The in situ levels of the synapsins exhibited parallel increases rapidly after birth, reaching peak levels at 8 weeks, after which a slight decline was noted in synapsin I and synapsin IIb. In hippocampal transplants, a comparable increase in the synapsins was seen during the first 8 weeks in oculo. It is likely that the synapse formation in the hippocampal transplants represents synapses from neurons within the transplant, as well as from various peripheral ganglia that send collaterals into the graft. Peripheral and central synapses express different synapsin I: synapsin IIa and IIb ratios. When the ratios of the synapsin proteins in hippocampal transplants were examined ratios essentially identical to those seen in the normal hippocampus were found, despite the numerous peripheral neurites innervating the grafts. Immunohistochemical studies supported the immunoblot data, showing no detectable immunofluorescence with synapsin antibodies in fetal or newborn hippocampal formation. The density of immunoreactive profiles increased substantially both in transplants and in the hippocampal formation in situ during the first 2 postnatal months. In conclusion, the present data demonstrate that hippocampal transplants in oculo can develop significant levels of the synapsins and that there is no time lag in development in these levels compared to the hippocampal formation in situ.


Septotemporal variation of the supragranular projection of the mossy fiber pathway in the dentate gyrus of normal and kindled rats. Previous studies have demonstrated regional variation in the anatomical organization and physiological properties of the hippocampus along its septotemporal (dorsoventral) axis. In this study, regional variation of the supragranular projection of the mossy fiber pathway in the dentate gyrus of normal and kindled rats was characterized with a scoring method for assessment of the distribution of mossy fiber synaptic terminals detected by Timm histochemistry. In normal rats, there was a sparse projection of the mossy fiber pathway into the supragranular region near the tips and crest of the dentate gyrus along the entire septotemporal axis, and a prominent projection into the supragranular region at the temporal pole. Kindling of the perforant path, amygdala, and olfactory bulb induced synaptic reorganization of the mossy fiber pathway into the supragranular region along the entire septotemporal axis of the dentate gyrus. There was regional variation of the seizure-induced synaptic reorganization along this axis, and distinct septotemporal patterns were observed as a function of the site of kindling stimulation. Kindling of the perforant path induced mossy fiber synaptic reorganization that was relatively more prominent in the septal pole than in the temporal pole of the dentate gyrus. In contrast, rats that received kindling stimulation of the amygdala had a more uniform distribution of synaptic reorganization along the septotemporal axis. As there is regional variation of the anatomical and physiological properties of the human epileptic hippocampus, these observations could be pertinent to human epilepsy.


Maintained saturation of hippocampal long-term potentiation does not disrupt acquisition of the eight-arm radial maze. The present experiment examined the anterograde effect of bilateral saturation of long-term potentiation (LTP) of the rat perforant path-granule cell response on acquisition of the eight-arm radial maze. To ensure maintained saturation, high-frequency stimulation was applied to the perforant path immediately prior to each trial. LTP did not significantly increase the number of trials required for acquisition of the standard eight-arm radial maze task. Furthermore, the magnitude of LTP did not correlate with the rate of acquisition. LTP also did not significantly affect the number of either working or reference memory errors during subsequent training with only four of the eight arms baited; both control and LTP rats made significantly more reference memory than working memory errors, with the number of both types of errors decreasing as training progressed. These results indicate that prior saturation of LTP within the perforant path-dentate granule cell circuit does not affect acquisition of either the reference or working memory components of the radial maze task. The results are discussed in relation to the role of LTP in acquisition of the eight-arm radial maze.


Amygdala kindling-induced seizures selectively impair spatial memory. 1. Behavioral characteristics and effects on hippocampal neuronal protein kinase C isoforms. Protein kinase C (PKC) comprises a family of kinases consisting of nine subspecies that are differentially distributed in the central nervous system. This implies distinct functions. Its involvement is suggested in cellular and molecular mechanisms by which the hippocampus exerts influence on information processing. In this study, it was questioned whether abnormal activity in the neuronal substrate, particularly the hippocampal formation, induced by amygdala kindling indeed impairs spatial memory performance and correlated alpha, beta I/II, and gamma PKC subspecies expression. Rats were trained in a spatial discrimination task (SDT) and simultaneously kindled in the amygdala to induce abnormal, epileptiform activity. Control rats were only trained in the holeboard, a "free choice" maze, in which working (WM) and reference memory (RM) were simultaneously examined. Halfway through and at the end of the experiments the influence of kindling and SDT training on the immunoreactivity for PKC subspecies alpha, beta I/II, and gamma was evaluated in the hippocampal formation. Kindling resulted in a gradual increase in afterdischarge duration and motor seizure (MS) severity. Repeated SDT training ultimately resulted in an asymptotic level of WM and RM performance. As soon as generalized MSs developed, kindled rats failed to improve RM, whereas WM was not influenced. Compared to untrained rats, in trained controls PKC gamma but not PKC alpha beta I/II immunoreactivity was elevated in CA1 pyramidal and dentate gyrus granular cells. Generalized but not partial MSs abolished these alterations in PKC gamma immunoreactivity. The present data indicate that repeated training in a SDT affects the expression of PKC subspecies gamma but not of alpha or beta in the rat hippocampus. Generalized epileptiform activity impair both acquisition of new spatial RM information and PKC gamma expression. It is argued that PKC gamma plays a role in cellular mechanisms through which pathological brain activity impairs certain aspects of spatial memory.


Amygdala kindling-induced seizures selectively impair spatial memory. 2. Effects on hippocampal neuronal and glial muscarinic acetylcholine receptor. The muscarinic acetylcholine receptor is linked via hydrolysis of phosphoinositides to the protein kinase C pathway. In a preceding paper (Beldhuis, H. J. A., H. G. J. Everts, E. A. Vander Zee, P. G. M. Luiten, and B. Bohus (1992) Amygdala kindling-induced seizures selectively impair spatial memory. 1. Behavioral characteristics and effects on hippocampal neuronal protein kinase C isoforms. Hippocampus 2:397-410), the role of different isoforms of protein kinase C in neurobiological processes associated with plasticity was studied using both a spatial learning paradigm and amygdala kindling in the rat. This study extended the findings on protein kinase C activity to the level of the muscarinic acetylcholine receptor. Rats were trained in a spatial learning paradigm and kindled simultaneously in the amygdala to develop generalized motor convulsions. Control rats were trained only in the spatial learning paradigm to acquire stable working and reference memory performance. Alteration in the expression of the muscarinic acetylcholine receptor was investigated using a monoclonal antibody to muscarinic acetylcholine receptor proteins. Trained control rats that were exposed repeatedly to the spatial learning paradigm showed an increase in immunoreactivity for the muscarinic acetylcholine receptor located in the same hippocampal regions in which the protein kinase C activity was increased. In fully kindled rats, however, this increase located in principal neurons was absent, whereas expression of muscarinic acetylcholine receptor proteins was increased in hippocampal astrocytes. Moreover, fully kindled rats showed an impairment in reference memory performance as compared to trained control rats.(ABSTRACT TRUNCATED AT 250 WORDS)


Inverted-U relationship between the level of peripheral corticosterone and the magnitude of hippocampal primed burst potentiation. Studies have shown that peripheral levels of corticosterone correlate with the magnitudes of two well-described physiological models of memory, long-term potentiation (LTP) and primed burst (PB) potentiation. In the present experiments, the authors investigated the effects of experimenter-controlled manipulations of the levels of corticosterone on the magnitude of hippocampal PB potentiation in urethane-anesthetized rats. Primed burst potentiation is a long-lasting (at least 30 minutes) increase in the amplitude of the CA1 population spike and EPSP slope in response to physiologically patterned stimulation of the hippocampal commissure. The levels of serum corticosterone were controlled by implanting corticosterone pellets in adrenalectomized rats (ADX/PELLET). In the first experiment, a significant negative linear correlation between elevated (stress) levels of serum corticosterone (greater than 20 micrograms/dL) and the magnitude of PB potentiation in ADX/PELLET subjects (r = 0.60, P < .05) was found. In the second experiment, the shape of the corticosterone-PB potentiation function was different at low and intermediate levels of corticosterone than it was at high levels of corticosterone: There was a positive correlation at low levels (0-10 micrograms/dL), a peak response at intermediate levels (11-20 micrograms/dL), and a negative correlation at high levels (21-93 micrograms/dL) of corticosterone. Thus, the overall relationship between corticosterone and PB potentiation is an inverted-U function. These findings provide strong support for the hypothesis that corticosterone exerts a concentration-dependent biphasic influence on the expression of hippocampal plasticity.


Phenytoin prevents stress- and corticosterone-induced atrophy of CA3 pyramidal neurons. Repeated daily restraint stress and daily corticosterone administration to adult male Sprague-Dawley rats leads to decreases in the number of branch points and length of dendrites of CA3 pyramidal neurons of the hippocampal formation. This decrease is prevented by daily administration of the antiepileptic drug phenytoin (Dilantin), which is known to interfere with excitatory amino acid release and actions. Phenytoin had no obvious effect on behavior during and after stress and failed to prevent stress-induced reduction of body weight gain and stress-induced increases of adrenal weight relative to body weight; it also failed to attenuate glucocorticoid-induced diminution of the size of the thymus gland, indicating that it does not directly antagonize glucocorticoid actions. Stress- and corticosterone-induced effects on dendritic length and branch point number are more pronounced on the apical, as opposed to the basal, CA3 dendrites that receive the largest mossy fiber input from the dentate gyrus. Because phenytoin is also known to prevent ischemic damage, these results are consistent with a model in which stress- and corticosterone-induced CA3 dendritic atrophy is produced by excitatory amino acids released from the mossy fibers.


Age-related loss of axospinous synapses formed by two afferent systems in the rat dentate gyrus as revealed by the unbiased stereological dissector technique. Previous attempts to elucidate whether a loss of hippocampal synapses occurs during aging provided conflicting results, possibly due to the unavailability, at the time, of unbiased methods for synapse quantitation. This study was designed to reexamine the issue by means of modern technical procedures that provide unbiased estimates of synaptic numbers. Groups of 14 young adult (5 months old) and 14 aged (28 months old) male Fischer-344 rats were compared. Synapses were examined in the middle (MML) and inner (IML) molecular layer of the hippocampal dentate gyrus, where synaptic contacts are predominantly formed by different systems of afferents, the entorhinal and commissural-associational fibers, respectively. The number of synapses per neuron was estimated with the aid of the stereological dissector technique. The results showed that the total number of synaptic contacts per neuron was significantly diminished in the MML (by 23.6%) and IML (by 22.7%) of aged rats relative to young adults. This age-related synaptic loss involved axospinous, but not axodendritic, junctions of the MML (-24.4%) and IML (-24.0%). Both perforated and nonperforated axospinous synapses (distinguished by a discontinuous or continuous postsynaptic density, respectively) exhibited an age-dependent decrease in numbers, though this decrease did not reach statistical significance in the case of perforated junctions of the IML. The observed age-related loss of axospinous synapses may underlie the reduction in the amplitude of excitatory postsynaptic potentials and the decline in functional synaptic plasticity detected in the dentate gyrus of senescent rats.


Structural synaptic plasticity associated with the induction of long-term potentiation is preserved in the dentate gyrus of aged rats. Changes in synaptic numbers were examined in the hippocampal dentate gyrus of aged (28 months old) rats following the induction of long-term potentiation (LTP) by high-frequency stimulation of the medial perforant path carried out on each of 4 consecutive days. Potentiated animals were sacrificed 1 hour after the fourth stimulation. Stimulated but not potentiated and implanted but not stimulated rats of the same chronological age served as controls. Synapses were analyzed in the middle (MML) and inner (IML) molecular layer of the dentate gyrus. Using the stereological dissector technique, unbiased estimates of the number per neuron were obtained for the following morphological varieties of synapses: axodendritic synaptic junctions involving dendritic shafts, nonperforated axospinous synapses having a continuous postsynaptic density (PSD), and perforated ones distinguished by a fenestrated, horseshoe-shaped, or segmented PSD. The induction of LTP resulted in a selective increase in the number of synapses with segmented PSDs. This change was detected only in the potentiated synaptic field (MML), but not in an immediately adjacent one (IML), which was not directly stimulated during the induction of LTP. Comparison of these data with the results of our previous LTP study in young adult rats (Geinisman, Y. et al., 1991, Brain Res. 566:77-88) showed that the only significant difference in the absolute number of synaptic contacts per neuron between potentiated animals of the two chronological ages was an age-related reduction in segmented synapses of the MML. Relative increases in the number of segmented synapses per neuron were, however, virtually of the same magnitude in potentiated rats of both ages as compared with their respective controls. This finding may explain why senescent rats can be potentiated to the same extent as young ones.


Partial rRNA sequences in marine yeasts: a model for identification of marine eukaryotes. The V3 variable region of the large subunit rRNA was examined for nucleotide sequence signatures as potential taxonomic tools. Data are presented on 117 species, representing 23 genera of basidiomycetous yeasts. The results of nucleotide sequence alignments indicate that strains within species have identical base sequences and that species may differ from one another by one to more than 100 base positions. Phylogenetic analyses of the alignments indicates relationships among species, including the prediction of synonymous species and the clustering of species belonging to the Ustilaginales and Tremellales. These results suggest that species-specific nucleotide sequences can be used for the development of techniques for population analyses of a variety of marine and other microeukaryotes.


Nucleotide sequence of the 18S ribosomal ribonucleic acid gene from two teleosts and two sharks and their molecular phylogeny. The 18S rRNA sequence was determined for two teleostean fish species, Fundulus heteroclitus and Sebastolobus altivelis, and two sharks, Squalus acanthias and Echinorhinus cookei. To study the molecular phylogeny of these taxa, the sequences were compared with 18S rRNA sequences of the Coelacanth Latimeria chalumnae, the frog Xenopus laevis, and humans. Maximum parsimony analysis of the sequences resulted in a single most parsimonious tree that is in agreement with the expected phylogeny. The correct phylogenetic tree was also found when using S. altivelis alone as the teleost representative. In contrast, the most parsimonious tree found by using F. heteroclitus as the teleost representative presented anomalous groupings (the teleost branch being grouped with humans), matching results previously obtained. However, a bootstrap analysis showed that some branches containing anomalous relationships were not significantly supported. An explanation for this peculiarity, the differences between our tree and previously identified ones, and their phylogenetic implications are discussed.


Direct sequencing of mitochondrial DNA detects highly divergent haplotypes in blue marlin (Makaira nigricans). We were able to differentiate between species of billfish (Istiophoridae family) and to detect considerable intraspecific variation in the blue marlin (Makaira nigricans) by directly sequencing a polymerase chain reaction (PCR)-amplified, 612-bp fragment of the mitochondrial cytochrome b gene. Thirteen variable nucleotide sites separated blue marlin (n = 26) into 7 genotypes. On average, these genotypes differed by 5.7 base substitutions. A smaller sample of swordfish from an equally broad geographic distribution displayed relatively little intraspecific variation, with an average of 1.3 substitutions separating different genotypes. A cladistic analysis of blue marlin cytochrome b variants indicates two major divergent evolutionary lines within the species. The frequencies of these two major evolutionary lines differ significantly between Atlantic and Pacific ocean basins. This finding is important given that the Atlantic stocks of blue marlin are considered endangered. Migration from the Pacific can help replenish the numbers of blue marlin in the Atlantic, but the loss of certain mitochondrial DNA haplotypes in the Atlantic due to overfishing probably could not be remedied by an influx of Pacific fish because of their absence in the Pacific population. Fishery management strategies should attempt to preserve the genetic diversity within the species. The detection of DNA sequence polymorphism indicates the utility of PCR technology in pelagic fishery genetics.


Isolation and characterization of an autonomously replicating sequence (ARSD) from the marine yeast Debaryomyces hansenii. The marine yeast Debaryomyces hansenii is known to tolerate salinities ranging from 0 to 24%. As a first step toward the molecular analysis of halotolerance in this organism, we report the isolation of an autonomously replicating sequence (ARS) and its use in the construction of a shuttle vector. The ARS from D. hansenii (ARSD) is 0.4 kbp long, and the function rests in 0.13 kbp of the sequence. Sequence analysis of ARSD shows strong homology to ARS from other organisms, including a 12-bp consensus sequence common to all ARS functional in Saccharomyces cerevisiae.


Chemical identification of catfish growth hormone and prolactin. Isolation and primary structure of growth hormone (GH) and prolactin (PRL) from the pituitary gland of catfish (Ictalurus punctatus) are described. Alkaline extract of the pituitary glands was fractionated by gel filtration on Sephadex G-75, ion-exchange chromatography on DEAE-cellulose, and reversed-phase high-performance liquid chromatography on Octadecyl silica ODS. Catfish GH and PRL were identified by Western blotting with antisera against chum salmon GH and PRL. The catfish GH consists of 178 residues and is the most similar to carp GH, with sequence identity of 77%, although there is an uninterrupted deletion of 10 amino acid residues that corresponds to carp GH (90-99). The PRL is composed of 187 residues, which also exhibits the highest identity (79%) with carp PRL. Sequence identity between catfish GH and PRL is only 27%.


The use of the antiglobulin 'gel-test' for antibody detection. Four antibodies used routinely in-house for the assessment of antiglobulin reagents (anti-Fyb, anti-Jka, anti-S) were tested in parallel using tube and antiglobulin 'gel-test' low ionic strength antiglobulin techniques. In the latter the red cells are centrifuged following incubation through a dextran matrix incorporating an anti-human globulin reagent. The results show that the antiglobulin 'gel-test' was less sensitive than the tube technique in the detection of these difficult antibodies.


The gel test: some problems and solutions. The gel centrifugation test (GT) is a method of transfusion serology, based on the fact that, after centrifugation, unagglutinated red blood cells (RBC) pass easily through a gel, while agglutinated RBC do not. The introduction of the GT to our blood bank transfusion routine [strictly following the manufacturer's instructions (DiaMed ID Micro Typing System)] resulted in problems with the interpretation of the results. These were overcome after the introduction of modifications, which included: (1) the systematic use of 1% RBC suspensions; (2) the use of 50 microliters of 1% RBC suspensions and 25 microliters of serum in all tests; (3) the control of all negative indirect antiglobulin tests (IAT) and direct antiglobulin tests (DAT) by the addition of 50 microliters of a 1% IgG coated RBC suspension followed by centrifugation; and (4) the systematic use of saline-suspended RBC for ABO typing in patients with positive DAT.


The A1 (B) phenomenon: a monoclonal anti-B (BS-85) demonstrates low levels of B determinants on A1 red cells. A monoclonal anti-B (BS 85) that reacts strongly with red cells from weak B variants (B3, Bint and Bv) has demonstrated the presence of a trace of B on A1 red cells. The agglutination of group A1 red cells by an anti-B antibody is called the A1 (B) phenomenon and is the converse of the B(A) phenomenon seen with certain monoclonal anti-A antibodies. Fragile A1 (B) agglutination is best seen by spin-tube techniques and A1 red cells negative in saline tests are agglutinated by albumin and protease enzyme-enhanced tests, but no reactions are seen with A2 red cells. The A1 (B) reaction is specifically inhibited by B substance, and D-galactose and the galactose-containing sugars melibiose and lactose. Red cells from B variants showed differential inhibition patterns with various sugars. A1 transferase levels were normal even in the strongest A1 (B) reactive blood samples, although the plasma H transferase levels and H status of these red cells were elevated. This is in contrast to the B(A) phenomenon which is associated with elevated levels of B transferase. It is suggested that A1(B) overlapping specificity can occur because of a combination of higher H activity (and thus more H sites) together with normal levels of A transferase activity as they are 20% higher than normal levels of B transferase. The production of anti-B reagents free of the A1 (B) phenomenon with BS-85 is achieved by suitable dilution using quality control tests with protease-treated A1 red cells.(ABSTRACT TRUNCATED AT 250 WORDS)


Proteolytic activity during storage of platelets in plasma. Proteolytic activity was studied in platelet concentrates (PC) stored in plasma at 22 degrees C. In experiment 1, two PC with a higher (A) and a lower (B) white cell concentration were prepared from each of nine donors by centrifugation. Aliquots of the cell-free plasma, PPP, were stored as a control. Samples for the assay of fibrinopeptide A (FPA), elastase, spontaneous proteolytic activity (SPA), kallikrein-inhibiting activity, thrombin-antithrombin complexes (TAT) and D-dimers were collected initially and on days 1, 3, 5 and 7 of storage. Consumption of glucose, pH and concentrations of lactate dehydrogenase (LDH) and ATP were determined to investigate the metabolic status of the PC. The decrease in pH correlated to the leucocyte count, r = -0.74, P < 0.001 and to the increase in LDH, r = -0.74, P < 0.01. The levels of elastase and the SPA were consistently low in the PPP bags. In the PC elastase had increased by day 5 and the SPA by day 3; the levels in PC A were significantly higher than in PC B, P < 0.01. The leucocyte count correlated with the elastase activity, r = 0.71, P < 0.01, and with the SPA, r = 0.65, P < 0.01. A minor increase in FPA was demonstrated while no TAT and D-dimers could be detected. The cause of the formation of FPA was studied in experiment 2; three bags of PC and four of PPP were prepared from each of 16 donors. To the PC and three of the PPP bags either hirudin, aprotinin or no enzyme inhibitor (control) was added.(ABSTRACT TRUNCATED AT 250 WORDS)


Retention for a removable partial denture. This article addresses the complex nature of retention in a removable partial denture. Retentive features range from magnets and springs to clips, clasps, and interfacial surface tension. The retentive quality of an extracoronal clasp varies with the alloy, physical form, location on the abutment, and positional relationship to other elements. Surveying to identify both occlusogingival and mesiodistal undercuts when the path of random dislodging forces are not definitely controlled is needed for effective retention. Augmentation of ineffective retention in existing clasps should concentrate on methods of deepening the undercut or increasing the suprabulge. Tightening of clasps already in contact with a tooth frequently produces adverse changes.


Effects of labial margin design on stress distribution of a porcelain-fused-to-metal crown. This study compared the stress distribution of three porcelain-fused-to-metal labial margins on a central incisor under simulated occlusal force. The margin designs were rounded-shoulder, rounded-shoulder with a bevel, and a chamfer. Evaluation of mean equivalent Mises tensile stress did not show any difference at the cement-dentin and metal-cement interfaces of the three margins. The mean equivalent Mises tensile stress at the porcelain-metal interface was found to be significantly higher for rounded-shoulder when compared with the chamfer. There was no significant difference in the axial stresses along the three interfaces among the three margin designs. Statistically significant differences in radial stresses at some interfaces of the three margin designs were found. The change of cement thickness of the chamfer margin is significantly greater than that of either the rounded-shoulder or the bevelled-shoulder margin.


The in vivo wear resistance of 12 composite resins. The in vivo wear resistance of 12 composite resins were compared with an amalgam control using the Latin Square experimental design. Sixteen edentulous patients wearing specially designed complete dentures formed the experimental population. The Michigan Computer Graphics Measurement System was used to digitize the surface of the control and composite resin samples before and after 3-month test periods to obtain wear data. The 12 composite resins selected for this investigation based on their published composite classification types were seven fine particle composites, three blends, and two microfilled composite resins. The Latin Square experimental design was found to be valid with the factor of material being statistically different at the 5% level of significance. Wear was computed as volume loss (mm3/mm2), and all of the composites studied had more wear than the amalgam control (P = .001). After 3 months, the mean (error) of wear of the amalgam was 0.028 (0.006). Means (error) of wear for the 12 composites were ranked from most to least wear by mean wear volume loss. The absence of any relationship between mean wear volume loss and the volume percentage filler was confirmed by the correlation coefficient r = -0.158.


The effect of abutment angulation on stress transfer for an implant. This investigation compared the stress production characteristics of five abutment angulations for a specific implant system. Photoelastic resin was cast directly to a 3.75 x 10-mm Branemark fixture (Nobelpharma USA, Inc, Chicago, IL) in a 50 x 70 x 13-mm mold. A strain gauge rosette was also incorporated in the resin to allow precise determination of normal stresses at a specific point. Each 4-mm abutment (15 degrees, 25 degrees, and 35 degrees from Implant Innovations (West Palm Beach, FL) and 0 degree and 30 degrees from Nobelpharma) was assembled on the fixture, subjected to 178N load, and viewed with a circular polariscope. Observed fringes were photographed and strain indicator readings were recorded. Mean observed fringe order and mean principle stress and strain at the location of the rosette were determined. At the location of the rosette, all five of the abutments produced principal strains (compressive and tensile) within the physiological zone for bone. The rosette was located approximately 4 mm away from the fixture. Higher stresses and strains can be expected in regions closer to the implant.


Rates of osseointegration of dental implants with regard to anatomical location. Implantation of commercially pure titanium dental implants can be obtained predictably and consistently. The initial research focused on the edentulous population, with most of the fixtures being placed into the anterior mandibular area. There has been increased use of dental implants for partially edentulous patients. This study reports the results of 169 consecutively treated patients with 673 fixtures. Patients were observed for 7 months to 8 years following occlusal loading. Implant osseointegration was 89.1% in the anterior maxillae; 71.4% in the posterior maxillae; 96.7% in the anterior mandible; and 98.7% in the posterior mandible. Osseointegration may be most dependent on anatomical location in the jaws.


Compatibility of Type IV dental stone with polysulfide impression materials. In the American National Standards Institute/American Dental Association specification no. 19, compatibility of impression materials with dental stones is assessed by the presence of a 20-microns-wide line reproduced on an unmodified calcium sulfate dihydrate cast. In actual dental practice, modified type IV dental stones are used, although little is known of their compatibility with polysulfide impression materials. This study evaluated the compatibility of 6 polysulfide impression materials and 11 modified type IV dental stones. A line 20 microns wide was etched on four glass dies. Four samples of each combination of impression material and dental stone were prepared according to the manufacturer's directions with an additional 3 minutes for the final setting time. Compatibility was determined by the presence of the reproduced line on the dental stones, as observed under low angle 10 x magnification by four rater groups. The line was reproduced on all of the impression specimens, and the examiners recorded 66 positive identifications of the line on the stone casts out of a possible 1,056 ratings for a total of 6.25% of the specimens. Out of a possible 66 impression-stone combinations, only 18 reproduced the 20-microns line. The combinations reproducing the lines most frequently (75%) were Neoplex with Blue Die Stone (Columbus Dental, St Louis, MO) and Coeflex with Indic Die Stone (Coe Lab Inc, Chicago, IL). The study showed that many combinations of polysulfide impression materials and modified type IV dental stones did not reproduce the 20-microns line; therefore, not every polysulfide is compatible with every type IV dental stone.


The physiological effects of radiotherapy on oral tissue. An increasing number of head and neck cancer patients are undergoing radiotherapy along or in conjunction with other treatment modalities. Radiotherapy extending over a period of weeks produces a variety of clinical manifestations. This article discusses the physiological changes that occur due to radiotherapy to elucidate the changes seen clinically.


Screening for temporomandibular disorders: history and clinical examination. American Dental Association. A temporomandibular disorder (TMD) conference was convened in 1982 by the president of the American Dental Association. One of the objectives was to develop guidelines for a brief screening history and examination relative to TMD in order to determine whether there is a need for a more comprehensive evaluation. Based on these guidelines and under the auspices of the American College of Prosthodontists, this article discusses a simplified TMD screening and examination form that requires minimum time for both the patient (history) and health care provider (examination) to complete. Succinct recommendations are also presented to enable the health care provider to quickly determine if a more detailed TMD history and examination are warranted.


The dental curriculum: is is relevant to dental practice? Does the undergraduate dental curriculum devote the appropriate amount of time to those areas of dentistry that are relevant to today's general dental practice? In a survey of dentists who graduated between 1980 and 1985, it was determined that they felt curriculum offerings in orthodontics, research, endodontics, periodontics, oral surgery, fixed prosthodontics, and occlusion had not been extensive enough. However, graduates also reported that their educational experiences in biochemistry, dental laboratory procedures, gross anatomy, microbiology, and occlusion were too extensive.


The reporting of statistical inferences in selected prosthodontic journals. Dental periodicals are the fundamental source of prosthodontic research. The ability to understand and contribute to dental literature is basic to the prosthodontic profession. The purpose of this study is to tally relative frequency with which various descriptive (n = 18), graphical (n = 7), and inferential statistical procedures (n = 68) are used in the prosthodontic literature. Our method consists of four procedures: journal selection, choice of 1987 through 1988 articles with inferential statistical content, tally of the statistical procedures in those articles, and quality control procedures used in obtaining these data. At least 50% of 10 prosthodontists selected 17 of 100 journals most likely to be read by prosthodontists. In the 17 journals, 1,320 articles were screened of which 406 were selected and evaluated for their statistical procedures. The bar and line plots were the most common graphical procedures occurring in over one fourth of the 406 articles. Percentages, means, and standard deviations occurred in more than 40%. Although 58% used the .05 significance level, only 0.3% mentioned power. Analysis of variance was used more often than the t tests (42% v 29%), whereas correlation/regression (21%) and chi-square tests (14%) were used less often. The t tests, analysis of variance (Duncan, Tukey, and Student-Newman-Keuls multiple comparison procedures), chi-square tests, correlation and regression, and the Wilcoxon tests occurred in at least 5% of the 406 articles.


Titanium palate maxillary overdenture: a clinical report. A clinical technique of using a cast titanium base in a maxillary overdenture for a patient with bruxism who has a history of repeated midline denture fractures is presented. The advantages of a metal palate and the favorable properties of titanium are discussed. This treatment provides the practitioner with a practical option for successfully treating difficult overdenture or conventional denture patients.


Nontraumatic final impressions for fixed partial dentures. A nontraumatic, nonretraction impression technique is presented which uses the fabrication of an acrylic resin shell from an interocclusal wax impression. A crucial step in the procedure is obtaining the complete finish line of the preparation within the resin. This tray, which is filled with an elastomeric impression material, is combined with a triple tray of the same material to provide all the necessary relationships to construct a crown or coping. This procedure is especially efficient for multiple abutments during fixed partial denture construction.


Extraoral retention of an obturator prosthesis. In this study, a technique is described by which large obturators can be retained with an acrylic resin head plate. The technique entails attaching the prosthesis to an acrylic resin plate with a 2-mm-diameter wire and then attaching the plate to the patient's forehead with skin tape.


Fabrication of an obstructive sleep apnea prosthesis. Obstructive sleep apnea, a sleep disorder, is becoming more prevalent and requires prompt and effective treatment by the dental and medical specialties. Conservative treatment modalities (ie, intraoral devices that prevent or minimize airway obstruction by the tongue) are recommended for treating mild to moderate forms of OSA. This article describes a simplified technique for fabricating an intraoral OSA prosthesis.


Infant colic and maternal mental health: nursing research and practice concerns. This study compared the mental health of 12 mothers who had infants with colic to 12 mothers of infants without colic. Colic was defined as infant fussing/crying of at least 2 hours/day for at least 5 out of 7 days, infant cry high-pitched and pain-sounding, and maternal report of infant inconsolability. Mental health was operationalized as scores on the Profile of Mood States and the Symptom Checklist-90R. Mothers of infants with colic had multidimensional psychological distress; they reported more bodily dysfunction, fears, disordered thinking, depression, anxiety, fatigue, hostility, impulsive thoughts and actions; and they had stronger feelings of personal inadequacy or inferiority. Implications for nursing research and practice are discussed in the context of study findings.


Temperament and interactive effects: mothers and infants in a teaching situation. Temperament is a theoretical concept used to understand individual's behavioral styles. In this study, temperament was measured in 13-month-old infants (N = 51) and their mothers, who were also observed together in a teaching situation. The purpose of the study was to determine the relationships between maternal and infant temperaments and interactive behaviors in the teaching situation. Mothers were given 10 minutes to teach infants four tasks designed to assess qualitative aspects of the interaction. In general, the interaction between mother and infant had a synchronous quality that was influenced by, but largely independent of, the temperamental characteristics of mother and infant. Responsive maternal teaching behaviors were significantly related to positive infant affect during teaching. Weak relationships were found between the temperament variables and interactive behaviors in the teaching situation. When mothers and infants were matched on temperament characteristics, no effects of matching temperaments on interactive behaviors in the teaching situation were found. These findings suggest that mothers are able to adjust their behaviors to compensate for their infant's temperament. Based on these data, nurses can focus on the dynamics of the interactions themselves and avoid making judgments based on temperament alone when evaluating mother-infant relationships.


The relationship of attitudes, knowledge, and social support to breast-feeding. Although more women are initiating breast-feeding, few continue for more than 1-3 months into the postpartum period. The current report studied the relationship of attitudes, social support, experimental and demographic variables, and knowledge to length of breast-feeding. A totaL of 102 women were included in the study and were followed for 1 year. Perceived attitudes toward breast-feeding, selected demographic variables, and past experiences were related to length of breast-feeding.


Cystic fibrosis: adolescent and maternal concerns about hospital and home care. The purpose of this study was to describe problems occurring in adolescents with cystic fibrosis that related to home or hospital care, maternal concerns, and the role of the health-care professional in promoting care. Forty-question semistructured interviews of adolescents (N = 20) and their mothers (N = 12) were used. Interrater reliability (90%) was established through analysis of 8 audiotaped interviews and agreement on content analysis of the 32 interviews. Results are discussed according to five categories of concerns identified by adolescents: (a) knowledge deficits, (b) self-care/decision making, (c) home care management, (d) hospital care management, and (e) suggestions for health professionals. Mothers described six categories of concern: (a) fear, (b) effect on self, (c) disruption of family life, (d) health-care management at home, (e) health-care management in the hospital, and (f) suggestions for health professionals.


In vitro evaluation of NaF and APF-gel application on surface microhardness of enamel in children of low, optimum and high fluoride areas. An in vitro study was conducted on 78 sound human pre-molars collected from low (0.24 ppmF), optimum (0.7 ppmF) and known endemic fluoride areas (> 1.5 ppmF), to study the effects of topical application of sodium fluoride and APF-gel on surface microhardness of enamel of these three areas using Vickers microhardness measurements before and after application of topical fluorides at time intervals of 1/2 an hour, 6 hours and 24 hours. It was found that both the topical fluorides increased the surface microhardness of enamel in the three areas; the maximum increase in surface microhardness was observed in fluorosed teeth. APF-gel was found to be more effective than sodium fluoride.


Microleakage of composite-ionomer laminate restorations: an in vitro evaluation. The in-vitro study undertaken on sixty teeth, 30 each of second primary molars and first premolars to evaluate the effectiveness of sealing property of composite-ionomer laminate restorations given on buccal aspects of these teeth after either Dycal base, ionomer base not etched and ionomer base etched indicated significantly more microleakage in dycal base composite resin restorations than composite ionomer. No difference in microleakage was seen in etched and unetched composite ionomer laminate restorations. Though microleakage was observed more in primary teeth than permanent teeth it was not found to be statistically significant.


Dentigerous cyst--an attempt to ascertain the normal eruption of involved tooth in child patient. Dentigerous Cyst, in a young patient, located in the right palatal region, extending from 61 to 55, limited to the right side of mid-palatine suture and treated by marsupialization with post operative follow-up of 6 months has been reported. The involved permanent tooth (21) entrapped in the cyst was not extracted and found to erupt in normal direction.


Taurodontism and pyramidal molars.

Taurodontism and pyramidal molars. The present study was conducted to investigate the occurrence of taurodontism and pyramidal molars in Goa children, hitherto considered rare in Indians. Radiographs of 300 children of 9 to 13 years were evaluated. The criteria of Keene (1966) was used to designate taurodonts. Ten children showed taurodontism: involving mandibular second molars in eight cases, maxillary first molars in three cases; and pyramidal molars in three cases, four cases showed associated findings. Hypodontia of one to fourteen teeth was observed in all four cases. In addition one case showed thinning of maxillary central incisors, rotation of lateral incisors, impacted supernumerary and a canine and polydactyly of hands and feet. The condition does not appear rare in this population group.


Use of sedation analgesia for pediatric dentistry. 26 healthy children between the ages of 36 and 60 months (mean 35 months) who satisfied the selection criteria during a screening visit participated in this double blind study. The subjects were assigned randomly to receive either 75 mg/kg Triclofos elixir (Regimen I-21 children) or 50 mg/1kg Trichlofos elixir combined with 1 mg/kg promethazine elixir (Regimen II-22 children). All medications were given orally 45 minutes before treatment. During operative procedures all subjects received nitrous oxide/oxygen at a concentration of 35%. All the patients were restrained in a papoose board (Indigenous). The subjects were monitored for vital signs and evaluated for sedation and sleep, movement, crying and overall behaviour before, during and after the operative procedure. Regimen II was found to be superior to Regimen I with regard to behaviour management of difficult young children. However extremely apprehensive children were not good subjects for this sedation technique.


Prevalence of thumb sucking in children of Calcutta. The prevalence study of thumb digital sucking carried out on 3-12-year- old 2517 children, 1293 boys & 1224 girls, with different socio-economic status, belonging to villages, suburbs and city areas of Calcutta revealed that non-nutritional sucking habit was predominantly seen in cities, and bottle feeding was found to be the main cause of this habit; in 3-6-year-old children the prevalence of the habit was more in boys than girls but it persisted more in boys with increase in age.


Interrelationship between sugar and dental caries--a study in child population of Orissa. An epidemiological study on interrelationship between dental caries and sugar consumption conducted on 1265 children in the age of 5-15 years revealed a positive association of dental caries experience with total sugar exposures, between meal sugar exposures and at meal sugar exposures. As the total increased from 3 to 4 in a day, a corresponding jump of 1 deft+DMFT and 2 defs+DMFS was noted, which was clinically and statistically significant. It was deduced that total sugar exposures per day should be limited to 3, out of which two should be at meal time and one between meals.


Evaluation of KAP of oral hygiene measures following oral health education through existing health and educational infrastructure. This study is a part of a larger preventive oral health feasibility module embarked on a population of 120,000 of Raipurrani, district Ambala (Haryana). The KAP analysis of about 2000 individuals (including school children) on cross-sectional basis at baseline, one and two years after the implementation of knowledge about oral health measures to the community utilizing the existing health infrastructure at CHC, the Anganwadi workers (ICDS Scheme) and through school teachers in the schools revealed that at baseline datun was the most prevalent (63%) oral hygiene measure used in the community and students. After implementation, the practice of brushing thrice, twice and once daily increased but the most prevalent frequency remained once a day (39% out of 66 percent using brush in community and 37% out of 76 percent in students after 2 and 11/2 years of implementation respectively) followed by twice a day (23 & 31% respectively). A similar pattern of frequency was observed about datun users also, though the number using datun substantially declined from 62% to 33% in community and 63 to 23% in students after implementation.


An occupational hygiene survey in a Chinese viscose rayon factory. The retinopathy (microaneurysm/small dot hemorrhage) is an early and specific biological indicator to quantitatively evaluate the CS2 exposure. The appearance of retinal lesions was observed among Yugoslavian, German and American workers exposed to CS2. However, among Finnish CS2 workers a positive result was not obtained. We suggested a different response to CS2 exposure between two ethnic populations. We had an opportunity to do a cross-sectional medical and occupational hygiene survey in a Chinese rayon staple plant. Cross-sectional medical examinations failed to show any chronic CS2 effects on the Chinese workers.


Histochemical study on the gland of pelvis renalis in the horse. The glands of pelvis renalis in adult and fetal horses were examined by histochemically. The glandular terminal was divided into two types, intraepithelial gland (IE) and extraepithelial gland (EE) by their locations and histochemical characters. Both glands were composed of mucous cells. The former lay in the transitional epithelium and were stained reddish with galactose oxidase-Schiff (GOS) and mild oxidation-Schiff (MOS), bluish purple with periodic acid-cold thionine Schiff-NaOH-PAS (PCP). The latter distributed in the lamina propria, but was not discovered in the fetus. They were stained weak or negative with GOS and MOS, reddish purple with PCP. Their difference of histochemical character might be reflect to chemical structure of the sialic acid. These mucous cells may cope with the urine contents as hippuric acid.


Heterogeneity of monoclonal immunoglobulins with antistreptolysin-O activity detected in the cases of essential monoclonal gammopathy and multiple myeloma. Two different types of monoclonal human immunoglobulins (M-components) with antistreptolysin-O (ASO) activity were investigated. The M-component FM with essential monoclonal gammopathy revealed to have an ASO activity, demonstrated not only by streptolysin-O neutralizing assay according to Ranz-Randall's method, but also by passive agglutination assays and precipitation on agar. The ASO activity was shown to reside in the Feb. These findings suggest that the M-component FM have a true antibody activity. On the other hand, ASO activity of M-component TT with multiple myeloma was detected only by streptolysin-O neutralizing assay, but the passive agglutinating assays and precipitation on agar showed no positive results. It has not been fully confirmed if the M-component TT behaves as a true antibody activity. Heterogeneity of the M-components with ASO activity was discussed.


Higher sensitivity of the developing larvae of Angiostrongylus cantonensis than the adult worms to flubendazole and mebendazole. Two kinds of benzimidazoles, flubendazole and mebendazole were each administered at 10 mg/kg to rats harbouring the developing larvae of the rat lungworm, Angiostrongylus cantonensis 3 or 10 days post-infection and to those harbouring the adult worms 70 days post-infection. Almost all of the larvae were eliminated from the rats mediated 3 days post-infection. The larvicidal effects of the drugs administered 10 days post-infection were not so high as those 3 days post-infection. However, the growth of larvae in rats medicated 10 days post-infection were significantly inhibited as judged from their length, width and weight except the length of the larvae in rats given mebendazole. An inhibition of their growth was also demonstrated by the observation that no first-stage larvae were released from the rats medicated 10 days post-infection and examined 66 days post-infection at which the first-stage larvae were released from non-medicated rats. On the other hand, when the drugs were administered 70 days post-infection, no effects were seen on the number, body size and weight of recovered worms, and the release of the first-stage larvae. A sound conclusion was drawn that the developing larvae are more sensitive to the drugs than the adult worms.


Immune recognition of human T-cell leukemia virus type-I (HTLV-I) by MHC-restricted cytotoxic T lymphocytes. In our studies, it was demonstrated for the first time that HTLV-I gag and pX, and env and pX antigens are the target antigens recognized by CD8+ CTL in association with RT-1k and RT-1l class I antigens, respectively, in the rat system. Furthermore, the gag-expressing rVV and the env-expressing rVV were shown to have the potential to induce HTLV-I-specific CTL in WKA and LEW rats, respectively. These results suggest that, in general, HTLV-I structural and non-structural antigens can be recognized by CTL, and their immunogenicity for the induction of HTLV-I-specific CTL may be influenced by host MHC. Successful vaccination of mice against retrovirus tumorigenicity with the viral structural components has been demonstrated. As was the case with polyoma virus-induced tumors, utilization of rVV vectors containing HTLV-I genes for potential HTLV-I vaccines in humans may become possible if target antigens recognized by each recipient CTL can be identified prior to vaccination. Another vaccine candidate will be a synthetic peptide containing each CTL epitope. We are currently identifying the CTL epitopes, and recent results indicate that a major CTL epitope on the env-gene product is located between the env amino acids 101-112 (Tanaka et al., manuscript in preparation).


The effect of glucocorticoids on the development of murine granulocyte-macrophage (GM) progenitors. The effect of glucocorticoids was tested on the hematopoietic system by assay of the ability of granulocyte-macrophage colony forming cells (GM-CFC) in mice to create GM colonies. The in vivo ability of bone marrow progenitor cells to granulocyte-macrophage colony formation was tested after long-term peritoneal glucocorticoids administration. The direct effect of these agents on cells in vitro culture was evaluated also. It was found that glucocorticosteroids inhibit the GM colony formation. The degree of damage to the bone marrow progenitor cells assaying by in vivo colony formation inhibition depends on the drug dosage and the length of therapy. The in vitro inhibition of granulocyte-macrophage colony formation depends on the concentration of the drug. The results suggest the possibility of the GM-CFC growth testing as an indicator of the side effects of prolonged corticoid therapy.


Chronic cutaneous lupus erythematosus and subsequent infection with HIV1. Since the beginning of the pandemia caused by the Human Immunodeficiency Virus several reports have described cases of infection by HIV1 in patients bearing rheumatic diseases. The infection by HIV 1 in patients with Systemic Lupus Erythematosus (SLE) and Chronic Cutaneous Lupus Erythematosus (CCLE), however, seems to be elusive. As far as we know, only 3 cases of HIV infection associated with SLE have been published. Furthermore, we have not been able to find out any report concerning HIV infection in patients bearing CCLE. The aim of the present article is to present a case of a female patient with CCLE that subsequently developed an infection with human immunodeficiency virus.


Dietary cholesterol induced changes in serum lipoproteins in healthy females. We studied the effect of high cholesterol fat breakfast containing approximately 527 mg cholesterol and 33 gm fat given for seven days in 10 healthy females of young age (18 to 21 years) and in healthy older females of age group (48 to 60 years). Serum total cholesterol and low density lipoprotein did not alter significantly after feeding and after withdrawal of high cholesterol fat breakfast. Serum high density lipoprotein increased significantly in young females after feeding and further increased after withdrawal for seven days, while in older females no appreciable change occurred. Serum triglyceride showed a significant decline in young persons after feeding but gradually increased after withdrawal while in older females no significant change occurred.


A single preoperative dose of cefazolin versus postoperative amoxicillin and gentamycin combination in prophylaxis of orthopaedic and traumatologic surgery. The use of antibiotic prophylaxis was evaluated in 228 surgical patients. The patients were given either cefazolin preoperatively or amoxicillin + gentamycin postoperatively in a randomized fashion to determine whether cefazolin would demonstrate an advantage over amoxicillin + gentamycin with respect to protection against postoperative wound infection, systemic infection and cost. We also tried to find out if the inflation of a tourniquet would interfere in the incidence of wound infection. Major postoperative wound infections were reduced in the cefazolin treated group (2.56 per cent versus 4.50 per cent). There also was a reduction in minor postoperative wound infections in the cefazolin group when it was compared with the amoxicillin + gentamycin group (6.83 per cent, 13.51 per cent, respectively). No systemic infection was seen in either group. There was no difference between the patients on whom were used tourniquets or not. Analysis of patients' charges suggested that 68.75% of the cost of preoperative antibiotic prophylaxis might be saved by limiting the duration of prophylactic drug administration by cefazolin.


Cyclophosphamide effect on ultrastructural myocardial changes in rats on low-magnesium diet. Intraperitoneal cyclophosphamide administration to a total dose of 225 mg/kg body weight during six weeks produced in rat myocardial fibres evident focal degenerative changes in all organelles, and, fairly frequently, significant damage even up to necrosis. The experiment showed that in rats on low-magnesium diet cyclophosphamide produced more intense and more extensive changes than in rats receiving only cyclophosphamide. The extent of the lesions produced with low and high doses of cyclophosphamide was compared and it was observed that the lesions increased with an enlargement of doses of the drug.


Effect of ketamine on contractile performance of isolated frog myocardium and comparison of ketamine, thiopental and droperidol. The influence of ketamine on the inotropic and chronotropic responsiveness of heart muscle was examined in spontaneously beating frog ventricular preparations. Ketamine produced a slight positive inotropic effect in isolated strips from the ventricle of the frog at 10(-5) M concentration. It does, however, possess negative inotropic properties at the higher doses studied (> or = 10(-4) M). Ketamine also decreased the heart rate of the ventricle at doses greater than 10(-4) M. Prior muscarinic blockade with atropine (10(-6) M) and histaminergic- H2 blockade with cimetidine (10(-5) M), did not affect the negative inotropic action of ketamine. Thiopental and droperidol also depressed the contractile performance of the frog myocardium. pD2 values of ketamine, thiopental and droperidol were found to be 3.44 +/- 0.63, 3.36 +/- 0.74, 4.18 +/- 0.45 respectively. These results suggest that the negative inotropic effects of ketamine is evident only at high concentrations and appears to be non specific.


The histopathological comparison of the results of the intra-arterial injections of propofol and thiopentone in rabbits. The results of injections of propofol and thiopentone intra-arterially are compared in rabbits according to histopathological criteries. Thirteen New Zealand type rabbits are used. Two ml of 2.5% Thiopentone and 2 ml of 1% Propofol are administered to the rabbits under anesthesia. Three days after, their ears are amputated and sent to this pathological blind examination. In both groups, we saw neither a morphological change along the vessel walls nor significant bleeding. But between the groups there was a significant difference about oedema. Consequently, 2.5% thiopentone which is routinely used after intra-arterial administration, may be responsible of the gangrenous change but it is discussable and it makes significant oedema in animal models although propofol does not have this effect.


Role of pi form of glutathione S-transferase (GST-pi) in cancer: a minireview. The pi class of the glutathione S-transferases is the most abundant of the human glutathione S-transferases family and is expressed almost in all tissues. However, the role of this protein is still poorly defined. It is suggested that this protein may serve as a marker for malignant transformation in some tissues. Additionally it seems that the phenomenon of tumour drug resistance may depend on the elevation of the glutathione S-transferase-pi. In this article we have attempted to review present knowledge concerning above problems.


Thermal effect of glucose in women with normal carbohydrate tolerance: relationship to body mass index, blood insulin and noradrenaline. Relationships between energy expenditure, body mass index (BMI), blood glucose (BG) responses to glucose ingestion were studied in 35 women aged 22-55 yrs with normal carbohydrate tolerance. In 13 of them plasma insulin (IRI) and catecholamine concentrations were also determined. Thirty seven per cent of patients did not respond to glucose load with an increased energy expenditure. In the remaining women the average thermogenic effect amounted to approx. 10% of their initial metabolic rate. A significant negative correlation (r = -0.415, n = 35, P(0.02) was found between BMI and the overall thermal effect of glucose (sigma TEG) calculated as a sum of the post-glucose energy expenditure measured every 15 min during 2 h minus the baseline value. Neither the fasting nor the post glucose BG concentrations correlated with sigma TEG. Significant correlations were ascertained between sigma TEG and the fasting IRI (r = -0.568), the sigma post-glucose IRI (r = -0.723), the ratio of sigma BG/sigma IRI (r = 0.845) and the post-glucose plasma noradrenaline concentration (r = 0.837). in women with normal carbohydrate tolerance the thermogenic effect of glucose depends to a large extent on insulin sensitivity and the glucose-induced activation of the sympathetic nervous system.


Gastrocolic fistula due to gastric cancer (a case report). Gastrocolic fistula originating from gastric cancer is a rare complication. Allison [1] collected 233 reports on patients with fistulas due to malignant tumours of the stomach and colon. In this article, a patient suffering from gastrocolic fistula as a complication of gastric carcinoma is presented.


Gastrointestinal fistulas.

Gastrointestinal fistulas. Gastrointestinal fistulas present a difficult problem to solve for the surgeons. Inspite of the recent progresses in diagnostic and therapeutic modalities, morbidity and mortality rates are still high. In this paper, we present our experiences on the postoperative gastrointestinal fistulas. We postulate that it is always better to prevent fistula formation rather than to cure it.