Xq28: epidemiology and sex-linkage between red-green colour blindness and G6PD deficiency. Xq28 is the genetic locus of two closely associated conditions of red-green colour blindness and G6PD deficiency. Epidemiologically, both rank among the more frequent sex-linked clinical problems that affect military servicemen in Singapore. This retrospective study is based on the findings of 35714 subjects screened at the Medical Classification Centre--Central Manpower Base (MCC--CMPB) over an eighteen-month period using pseudoisochromatic and fluorescent techniques as well as anomaloscopic and spectrometric methods. The overall prevalence rates of red-green colour blindness, G6PD deficiency and association were determined to be 4.8%, 2.2% and 0.1% respectively. Malays showed the highest prevalence rates among the major races. Statistically significant difference was found with regards to the prevalence rates of G6PD deficiency and its association with red-green colour blindness. Review of literature yielded comparable results with a few local studies of good sample size done over the past twenty years. Sex-linkage analysis was hindered by the lack of pedigree studies.


A prevalence study of dysmenorrhoea in female residents aged 15-54 years in Clementi Town, Singapore. A community-based questionnaire survey to study the prevalence of dysmenorrhoea, its associated risk factors and impact on daily living was carried out on a random sample of 415 female persons aged 15 to 54 residing in Housing Development Board flats in Clementi Town. The overall prevalence of dysmenorrhoea, defined as one or more episodes of menstrual cramp or pain in the previous year, not due to a diagnosed gynaecological disease, was 51.3%. The condition was less prevalent and less severe in older women and in women with later menarche. It was also less prevalent in women who were parous, with the greatest number of parous women reporting improvement in severity after the first child. Among those with dysmenorrhoea, about 52% of students, 42% of working women, and 30% of housewives reported that their ability to perform work was affected. About 6% of all women consulted a doctor for their problem, and 10% of all employed women reported having been sick-absent because of dysmenorrhoea.


Cervical cancer: trends in incidence and mortality in Singapore 1968 to 1987. Analysis of data collected by the population-based Singapore Cancer Registry reveals that the age-standardised incidence of cervical cancer has decreased from 18.2 per 100,000 females in 1968-72 to 16.2 per 100,000 in 1983-87, and its ranking among the most common female cancers has fallen from second to fourth place behind cancers of the breast, colon/rectum and lung. Mortality from the disease has also shown a corresponding fall from 7.3 per 100,000 to 5.5 per 100,000 women over the same period. Cervical cancer incidence rates are in general highest among Indian women, intermediate in Chinese and lowest in Malays. Age-specific incidence curves over time show a marked fall in rates in women over 50 years of age, whereas younger women (35-44 years old) show a small increase. A similar increase in rates has been observed in various other countries. Internationally, Singapore's incidence rate falls between the highs of South America and parts of Asia, and the lower rates of North America and Europe. The decrease in rates is comparable with the overall global trend, but falls short of that achieved by countries with systematic cytological screening programmes.


Prevalence of protein calorie malnutrition in general surgical patients. The prevalence of protein calorie malnutrition (PCM) based on ten nutritional parameters was studied in 307 patients undergoing major elective surgical operations. These parameters included anthropometric measurements (weight/height, triceps skin fold thickness, arm muscle circumference) and biochemical (serum total proteins, albumin, transferrin, prealbumin, retinol binding protein) and immunological tests (total lymphocyte count and delayed hypersensitivity test). Using these criteria, the prevalence of PCM was high. Eighty-six percent of patients had at least one abnormal parameter. The prevalence of PCM as judged by weight/height and arm muscle circumference was 49% and 62% respectively. The incidence was higher in cancer than non cancer patients (63% vs 43%). Although serum albumin and total protein levels were normal in 93.5% of patients, acute serum protein markers such as transferrin, prealbumin and retinol binding protein were low in 20-30%. Lymphopenia of 1500 cells/cu mm or less was found in 18% and abnormal delayed hypersensitivity test in 60%. We found that only weight/height, serum protein, transferrin and lymphopenia had predictive values in postoperative morbidity and mortality. By identifying PCM patients early, adequate nutritional support can be given in order to reduce the risk of major surgical complications.


Treatment of spontaneous uncomplicated pneumothorax with aspiration. Between December 1989 and December 1990, nine patients with significant, uncomplicated, spontaneous pneumothoraces were treated by simple aspiration in the Medical Department, Alexandra Hospital. Only one had a residual 30% pneumothorax that required further aspiration with good results. The majority of the patients stayed three days in hospital. These nine patients were reviewed at various periods between four weeks to twelve months with no recurrence of pneumothoraces. The discomfort and inconvenience of an intercostal tube insertion was avoided. Risk of damage to the lung was minimal. No scar was left behind. Total cost of the procedure and hospitalisation was much less compared with intercostal intubation.


Acute deep vein thrombosis in hospital practice. A recent cross sectional study on symptomatic acute deep vein thrombosis at the National University Hospital (NUH) in Singapore found a frequency rate of 0.79 per 1000 patient admissions. A total of 39 patients were accrued over 18 months, 36 with deep vein thrombosis alone and three complicated by pulmonary embolism. No sex or ethnic predilection was observed in this cohort of hospitalised patients. Twenty-eight (71.8%) patients were 40 years or older. Majority (89.7%) of patients had at least two predisposing factors. While prolonged bedrest and operative procedures featured equally frequently in patients above and below 40 years, neoplasms were predominantly associated with the former and protein C or S deficiency primarily with the latter. The exhaustive laboratory confirmation of an inherent thrombotic tendency is recommended only for patients below 40 years of age.


Clinical study of magnetic stimulation of peripheral nerves. Magnetic stimulation of the peripheral nerves is a recently developed technique and has exciting prospects in clinical neurophysiology. An experiment was performed comparing the conventional electric stimulation with magnetic stimulation of the median nerve of a normal population. Magnetic stimulation produced comparable results as far as latency, amplitudes and configuration of action potentials in most patients. The technique of magnetic stimulation is discussed. Its shortcomings are in locating the magnetic coil's point of stimulation on the nerve and difficulty in achieving supramaximal stimulation. Its great advantage is that it is painless and that deep nerves can be reached.


Infection in continuous ambulatory peritoneal dialysis (CAPD): aetiology, complications and risk factors. Continuous ambulatory peritoneal dialysis (CAPD) was started in the Singapore General Hospital in 1980. Peritonitis and exit site infections have been the major cause of morbidity and catheter loss in CAPD. In 1990, 130 patients were on CAPD and the peritonitis rate was one episode in 20.4 patient months. Gram positive organisms accounted for 54% of the infections of which Staphylococcus epidermidis was the commonest (24%). Catheter removal was required in 14% of the cases and 9% of the patients discontinued CAPD as a result of peritonitis. The exit site infection rate was one episode in 27.5 patient months and the commonest organism was Staphylococcus aureus (54%). Twenty-three (47%) of the cases of exit site infection required catheter removal and 83% of the cases were the result of S. aureus infections. Patients with preexisting exit site infections experienced more episodes of peritonitis. Patients above the age of 50 years experienced more episodes of peritonitis and exit site infection. Sex, diabetes and the duration on CAPD did not influence the frequency of infections. Patients using the UV Germicidal Exchange Device had fewer episodes of peritonitis than those using the conventional spike system.


Community acquired urinary tract infections in Singapore: a microbiological study. We studied 214 patients with culture proven community acquired infections. A total of 219 organisms were isolated, of which 68.2% were Escherichia coli, 10.1% Klebsiella sp and 5.5% Proteus mirabilis. Gram positive cocci accounted for 10.5% of organisms isolated. The majority of organisms isolated were sensitive to nalidixic acid (81.1%), nitrofurantoin (80.7%), cephalexin (74.7%) and trimethoprim-sulphamethoxazole (65.0%). Resistance to ampicillin was common (49.8%), as such the use of ampicillin in community acquired urinary tract infections will result in a high failure rate.


The impact of HLA match transfusions and presensitization on renal transplantation in the cyclosporine era. The successful engraftment of a renal transplant is dependent on multiple factors, immunological factors being of major importance. Specifically, histocompatibility, lymphocytotoxic antibodies and pretransplant blood transfusions have been shown to play a major role in determining graft outcome in renal transplant recipients receiving Azathioprine-Prednisolone immunosuppression. The impact of the immunosuppressive drug, Cyclosporine on graft outcome in relation to established risk factors were examined among 116 cadaveric and 34 living related renal allograft recipients from our center. Histoincompatibility and pretransplant blood transfusions did not significantly affect graft survival among cadaveric transplant recipients. Similarly, graft survival was not significantly different between two haplotype-matched and less well-matched living-related graft recipients (75% versus 96.5% respectively). On the other hand, lymphocytotoxic antibodies remained a major risk factor for immunologically mediated graft loss among cadaveric graft recipients (48.0% versus 92.2% four year graft survival among those with and without antibodies respectively). These results suggest that Cyclosporine has abrogated some immunological risk factors in renal transplantation.


Management of severe chronic radiation cystitis. Chronic radiation cystitis complicating pelvic irradiation can occasionally result in massive bleeding difficult to control with conventional means. Between 1986 and 1989, we managed 42 cases of chronic radiation cystitis of which nine (21%) were of this severe type based on the necessity for repeated cystodiathermy, massive transfusions and open surgical intervention. We found early cystodiathermy and alum bladder irrigation beneficial in early cases, but six (67%) patients required emergency bilateral percutaneous nephrostomies for proximal urinary diversions to help stop the bleeding. Despite aggressive treatment, two patients (22%) died during their admissions and two others (22%) died shortly after discharge. Three patients eventually required elective ileal conduit diversion for their contracted defunctioned bladder. Thus this group of patients suffered relatively high morbidity and mortality for an essentially benign condition. Increased physician awareness and timely percutaneous nephrostomies may improve results.


Exercise training in patients after heart transplantation. The post-cardiac transplantation patient is frequently debilitated as a result of "end-stage" heart disease and typically demonstrates muscle wasting, with a reduced work capacity, maximum heart rate and peak oxygen uptake. At submaximal effort, perceived exertion and ventilation are higher, and the absolute ventilatory threshold lower, than in normals. A number of published studies have now shown that an exercise rehabilitation programme can induce a good training effect, although possibly not complete restoration of physiological function. The prescription of exercise must take into account the denervated heart's peculiar response to effort, and rely more on perceived exertion and metabolic measurements for defining intensity of training rather than target training heart rates. Changes in mood and personality have also been noted in these patients, and while these may improve spontaneously with the passage of time, there is some evidence that a rehabilitation programme can help in this regard.


Calcifying epithelioma of Malherbe--a case report of a large preauricular tumour. Calcifying epithelioma of Malherbe (pilomatrixoma) is a relatively uncommon benign skin tumour of hair follicle origin. It usually presents in the face and upper extremities of young adults as an asymptomatic subcutaneous or dermal tumour. Treatment is surgical excision. This paper presents a case of a large tumour in the preauricular region with difficulty in diagnosis preoperatively and required a superficial parotidectomy to clear the tumour from the facial nerve.


Migrating foreign bodies in the upper digestive tract. Migrating foreign bodies in the aerodigestive tract are not so uncommon. Two cases of penetrating and migrating extraluminal foreign bodies in the upper aerodigestive tract are presented. Both patients had ingested fish bones. Fish bones are the commonest of bones to be ingested. Sharp and pointed fish bones are more likely to penetrate extraluminally. A high index of suspicion is necessary to institute early treatment. A CAT scan is invaluable in locating the foreign body especially with regards to surgical landmarks at exploration. Early surgical intervention avoids life-threatening complications.


Oculopharyngeal muscular dystrophy: a case report and a review of literature. Most muscular dystrophies manifest as peripheral muscular weakness commencing at various age, however, oculopharyngeal muscular dystrophy (OPMD) is a rare hereditary disorder presenting in middle age with progressive dysphagia and bilateral blepharoptosis rather than peripheral muscular weakness. In the medical literature, OPMD has been well described in Canadians of French descent. So far, there is no publication of OPMD in the Malaysia-Singapore medical literature. This article documents this condition in a Chinese patient. A review of the literature is presented and the management of OPMD is discussed.


Severe myelodysplasia with monosomies 5 and 7 presenting with rapidly fatal Sweet's syndrome. A 57 year-old Chinese man with anaemia and thrombocytopenia due to monosomies 5 and 7-associated myelodysplasia developed progressive Sweet's syndrome. Recurrent episodes of cutaneous manifestations responded dramatically to corticosteroid therapy. However, progressive pulmonary infiltrates unresponsive to antimicrobial therapy resulted in respiratory failure and death.


Fixed drug eruptions due to co-trimoxazole. Co-trimoxazole is a less common cause of fixed drug eruption (FDE). The offending drug is usually sulfamethoxazole but reactions to trimethoprim have been reported. Fixed drug eruption is uncommon in children compared to adults as the drugs most commonly responsible are seldom or never used in children. We report four patients with FDE to co-trimoxazole, three of whom were children. All were given the offending drug for upper respiratory tract infections. Each of the patients had several episodes of FDE before the diagnosis was suspected. The patients, as well as the general practitioners, initially thought that the skin lesions were related to the infections rather than the drugs. One of the patients had FDE to trimethoprim and the intensity of his reaction appeared to be dose-related. As co-trimoxazole is being used more commonly, we would expect to see more FDE, even among the paediatric age group.


Spasticity--implications in rehabilitation. Several features characterise spasticity which may be present in patients with lesions of the upper motor neurones of the brain and spinal cord. Spasticity gives rise to disability depending on the site and extent of the lesion. The manifestations of spasticity and its direct consequences on the locomotor system are discussed in this paper together with the factors affecting it. Management strategies in the rehabilitation of patients with spasticity are outlined, with emphasis on preserving maximum possible function in mobility and activities of daily living.


Social and cultural aspects of organ donation in Asia. In Asian countries, it is more difficult to obtain cadaver kidneys for renal transplantation because of certain socio-cultural beliefs and customs. The issues affecting living related kidney donation are more social than cultural. This is due to the web of family pressures and personal conflicts for both donor and recipient surrounding the donation. Important misconceptions and fears are: fear of death, the belief that removal of organ violates sanctity of decreased, concern about being cut up after death, desire to be buried whole, dislike of idea of kidneys inside another person, wrong concept of brain death, and the idea of donation being against religious conviction. In Singapore, with the introduction of the Human Organ Transplant Act (HOTA) in 1988, the number of cadaveric transplants have increased, including those from the Medical Therapy Act (MTA). HOTA and education have played pivotal roles in bringing about an increased yield of cadaveric kidneys. With the availability of living unrelated donor (LUD) transplants in India, our living related donor (LRD) transplant programme has suffered, because patients would rather buy a kidney from overseas than get a relative to donate one. Patients are also going to China for overseas cadaveric transplants where the kidneys come from executed convicts. People in countries like Hong Kong, Japan and the Philippines share the same Asian tradition of not parting with their organs after death. Muslim countries like Malaysia require the deceased to have earlier pledged his kidneys for donation prior to death before they can be harvested for transplantation at death.


Can therapeutic interventions prevent chronic renal failure? One way to prevent chronic renal failure (CRF) is to institute preventive measures against renal diseases in the general population. Patients with hereditary kidney diseases should have genetic counselling. Certain infections affecting or causing kidney diseases can be eradicated. People should be cautious in the use of analgesics and non-steroidal anti-inflammatory agents. Exposure to hydrocarbons, heavy metals and toxic gases should be avoided. Proper management of diabetes mellitus, gout, renal stones and hypertension can prevent renal damage. In patients with established renal disease, the following factors if treated or modified can prevent or ameliorate renal injury: glomerular hypertension, cell mediated proliferation, lipid induced proliferation, coagulation and thrombosis. Pregnancy in patients with renal disease should be well managed and termination advised if necessary. Reversible causes of renal failure as well as acute reversible elements can be removed or treated. Acute renal failure due to toxins can be avoided, although prevention requires awareness of association with renal failure. Prevention too depends on early detection of nephrotoxic injury like: greater awareness of hazards of environmental toxins, careful monitoring of dosage of nephrotoxic drugs and when possible, total avoidance of nephrotoxins should be the rule. Finally, in patients with glomerular disease, prevention or amelioration of glomerular damage with pharmacological agents have been achieved in some instances.


Medical aspects of drowning in children. Accidental, homicidal and suicidal drowning comprise a special challenge to the clinician and preventive medicine advocate, alike. In South-east Asia and Australasia, accidental immersion accidents rank highly among the causes of preventable child trauma. Bath-tub and bucket drownings affect infants and toddlers under the age of 12 months, and some 10 percent of fatal bucket-tub immersions affecting infants are the result of child abuse. Immersion accidents in the sea have special characteristics, not specifically as a result of differences in water osmolarity, but related to hypothermia, secondary lung complications, and immersion times. Swimming pool drownings are the major cause of preventable death affecting pre-school children in some regions of Australasia. Resuscitation of the near-drowned child is topical because, (a) of controversies about the optimality of mouth-to-nose expired air resuscitation (EAR) in infants under six months of age; (b) of controversies about the degree of brain damage among child survivors following intensive care salvage; and (c) the difficulties of having "every parent a first-aider". A major study of childhood immersions (The Brisbane Drowning Study has shown that of all survivors, some 70 percent will be completely normal, 30 percent will suffer some selective deficit (with wide disparities on sub-scale scores on formal IQ testing), and 3 percent will live in a permanent vegetative state. Vigorous preventative campaigns using the triad of (a) public media education and campaigns, (b) better safety standards and safety devices, and (c) safety legislation, can reduce both the population risk and the individual clinical severity of immersion accidents.(ABSTRACT TRUNCATED AT 250 WORDS)


Objective assessment of research performance. Research output in academic institutions need critical and objective assessment. Publications are an important avenue by which research by an academic can be evaluated. Journals in which such publications appear may be ranked and weight age given to publications in highly ranked journals. The number of citations of an academic's work by peers is another assessment of quality of research output. Firstly subjective peer assessment although flawed by interpersonal bias has its merits especially when evaluation is by an outsider of the institution.


Rapidly progressive autosomal dominant parkinsonism and dementia with pallido-ponto-nigral degeneration. We describe a family with nearly 300 members over 8 generations with 32 affected individuals who have an autosomal dominant neurodegenerative disease characterized by progressive parkinsonism with dystonia unrelated to medications, dementia, ocular motility abnormalities, pyramidal tract dysfunction, frontal lobe release signs, perseverative vocalizations, and urinary incontinence. The course is exceptionally aggressive; symptom onset and death consistently occur in the fifth decade. Positron emission tomographic studies with [18F]6-fluoro-L-dopa (6FD) were performed in 4 patients and 7 individuals at risk for development of the disease. All affected subjects had markedly reduced striatal uptake of 6FD (p less than 0.001). All individuals at risk had normal striatal uptake, but high 6FD uptake rate constants were noted in 3 of the 7 studied. Autopsy findings revealed severe neuronal loss with gliosis in substantia nigra, pontine tegmentum, and globus pallidus, with less involvement of the caudate and the putamen. There were no plaques, tangles, Lewy bodies, or amyloid bodies. This kindred appears to represent a neurodegenerative disease not heretofore described. We propose the following name for this new genetic disease: autosomal dominant parkinsonism and dementia with pallido-ponto-nigral degeneration.


Spectrum of human immunodeficiency virus-associated neocortical damage. A spectrum of neurocognitive defects, termed human immunodeficiency virus type 1 (HIV-1)-associated cognitive/motor complex, has been described in patients with acquired immunodeficiency syndrome (AIDS). AIDS dementia complex (ADC) is a severe form of this disease seen in 20 to 30% of terminally ill patients. The etiology of this complex is distinct from commonly observed opportunistic infections seen in brains of patients with AIDS and has been attributed to HIV infection within the brain. At autopsy, the brains of patients with ADC contain numerous HIV-infected macrophages/microglia with prominent subcortical damage, together termed HIV encephalitis. We retrospectively analyzed all 107 brains from a three-year period (1988-1990) of AIDS autopsies using immunocytochemistry to detect HIV. Rather than breaking into distinct groups of HIV encephalitis versus non-HIV encephalitis, the specimens revealed a spectrum of severity of HIV infection. Although only 16% of the brains showed the histological hallmarks of HIV encephalitis, more than 50% of the autopsies showed moderate to severe HIV infection. In a subset of 23 AIDS autopsies during which short postmortem times and absence of significant opportunistic infection permitted quantitative analysis of dendritic and synaptic complexities, we identified a strong correlation between neocortical dendritic and presynaptic damage and abundance of HIV envelope protein in the neocortical gray and deep white matter. This correlation suggests that the presence of HIV-1 in the neocortex may be responsible by direct or indirect mechanisms for dendritic and synaptic damage.


Angiotensin II receptor binding associated with nigrostriatal dopaminergic neurons in human basal ganglia. In the human brain, receptor binding sites for angiotensin are found in the striatum and in the substantia nigra pars compacta overlying dopamine-containing cell bodies. In contrast, angiotensin-converting enzyme occurs in the substantia nigra pars reticulata and is enriched in the striosomes of the striatum. In this study, using quantitative in vitro autoradiography, we demonstrate decreased angiotensin receptor binding in the substantia nigra and striatum of postmortem brains from patients with Parkinson's disease. In the same brains the density of binding to angiotensin-converting enzyme shows no consistent change. We propose, from these results, that angiotensin receptors in the striatum are located presynaptically on dopaminergic terminals projecting from the substantia nigra. In contrast, the results support previous studies in rats demonstrating that angiotensin-converting enzyme is associated with striatal neurons projecting to the substantia nigra pars reticulata. These findings raise the possibility that newly emerging drugs that interact with the angiotensin system, particularly converting enzyme inhibitors and new nonpeptide angiotensin receptor blockers, may modulate the brain dopamine system.


Motor inhibition and excitation are independent effects of magnetic cortical stimulation. We administered magnetic cortical stimulation (MCS) during voluntary contraction of intrinsic hand muscles to 8 patients with motor neuron disease (MND), 5 patients with pure lower motor neuron syndromes (LMN), a patient with severe subacute sensory neuropathy (SSN), and 10 healthy volunteers. Patients with MND had clinical evidence of upper MND and elevated thresholds for (3 patients) or absence of (5 patients) motor evoked potentials (MEPs). MCS during sustained contraction inhibited electromyographic activity in 6 of 8 patients with MND, without preceding MEPs. MCS had no effect on the electromyogram (EMG) of the other 2 patients with MND. In normal subjects and patients with LMN, inhibition of EMG was never seen without a preceding MEP, regardless of stimulus intensity. In the patient with SSN, MCS elicited normal MEPs and inhibited the EMG in a pattern similar to normal subjects, whereas supramaximal electrical stimulation of median and ulnar nerves failed to inhibit the EMG despite normal M and F responses. Our findings indicate that the inhibitory effects of MCS on EMG are not dependent solely on changes in afferent feedback caused by the muscle twitch produced by the MEP, or on Renshaw cell inhibition. We suggest that some of the inhibitory and excitatory effects of MCS on the motor system are mediated by distinct cortical elements, which may have different susceptibilities to pathophysiological processes in MND.


Facilitation of responses to motor cortex stimulation: effects of isometric voluntary contraction. In 7 normal subjects we compared the facilitatory effect of isometric contraction of the tibialis anterior on the size of electromyographic responses evoked in this muscle by electric stimuli applied over the cervical column and by electric and magnetic percutaneous stimulation of the motor cortex. No significant difference was found between the degrees of facilitation of the responses to any of the stimuli. Using collision techniques, we also showed that the pyramidal fibers activated by spinal and cortical stimuli are the same. Facilitation induced by isometric contraction (20% maximum) was of similar or greater magnitude than that found with constant vibration of the tendon of the target muscle. In cases where vibration and contraction had equal facilitatory effects, there was no further facilitation of the responses when both conditions were applied together. These findings indicate that the facilitatory effect of isometric contraction of the target muscle essentially originates at a spinal level rather than in the motor cortex.


Inverse relationship between education and parietotemporal perfusion deficit in Alzheimer's disease. A higher prevalence of dementia in individuals with fewer years of education has suggested that education may protect against Alzheimer's disease (AD). We tested whether individuals with more years of education have a more advanced AD before it is clinically evident. As a measure of pathophysiological severity, we quantified regional cerebral blood flow (rCBF), by the 133Xenon inhalation technique; a specific pattern of flow reduction in the parietotemporal cortex corresponds to AD pathology. In 3 groups of patients with probable AD, matched for clinical measures of dementia severity but with varying levels of education, whole-cortex mean flows were comparable. However, the parietotemporal perfusion deficit was significantly greater in the group with the highest level of education, indicating that AD was more advanced in this group. We conclude that education or its covariates or both may provide a reserve that compensates for the neuropathological changes of AD and delays the onset of its clinical manifestations.


Subclinical histopathological changes in the oculomotor nerve in diabetes mellitus. To provide reference values for the oculomotor nerve, for example, fascicular area and myelinated fiber (MF) number and size distribution, in pathological states, and to determine whether oculomotor nerves from diabetic patients without a history of oculomotor palsy have subclinical structural alterations, the morphometric features of 15 control subjects and eight diabetic patients were evaluated at a proximal and a distal level. On average the control nerves had a fascicular area of 2.7 mm2, 22,311 MF, and a bimodal diameter distribution with peaks at approximately 5 to 6 and 10 to 11 microns and a range of 2 to 20 microns. In proximal nerve, glial bundles were found in one-half of the subjects and patients, with a peak of MF sizes that differed from fibers in nonglial areas. The nerves from diabetic patients departed from the nerves from control subjects in the following two respects: changed size distribution, suggesting atrophy of fibers, and microfasciculation of edge fibers in parts of the fascicles in one-half of the patients. We conclude that glial bundles are probably a normal variant. Microfasciculation occurred much more frequently in nerves from diabetic patients and may represent subclinical injury of unknown cause. The alteration in size distribution may reflect the diabetic state and is not necessarily a precursor to diabetic ophthalmoplegia.


Felbamate monotherapy: controlled trial in patients with partial onset seizures. Felbamate (FBM) monotherapy was evaluated in 44 patients with uncontrolled partial onset seizures in a unique, single-center, randomized, double-blind, parallel-group trial. During the 56-day baseline period, patients were required to have at least 8 seizures and to be receiving only one standard antiepileptic drug (AED) at a therapeutic level; a second AED was allowed if at a subtherapeutic level. Patients were randomized to valproate (VPA), 15 mg/kg, or to FBM, 3,600 mg/day. In the treatment phase, previous AEDs were discontinued by study day 28 (by one-third decrements on study days 1, 14, and 28). Study end points were completion of 112 study days or the fulfilling of escape criteria. Criteria for escape relative to baseline were: two-fold increase in monthly seizure frequency, two-fold increase in highest 2-day seizure frequency, single generalized tonic-clonic seizure (GTC) if none occurred during baseline, or significant prolongation of GTCs. The predetermined primary efficacy variable was the number of patients escaping in each treatment group. Nineteen patients on VPA and 3 on FBM met escape criteria (p less than 0.001, chi-square test). When overall seizure frequency among study completers was compared with baseline, the FBM group had a 50 to 65% reduction in seizure frequency. FBM adverse experiences were all mild or moderate in severity, and the incidence of adverse experiences was lower in monotherapy. FBM monotherapy was effective in the treatment of partial onset seizures with or without generalization and demonstrated a favorable safety profile.


New anatomical and functional imaging methods. Powerful new methods for imaging both brain anatomy and brain function are appearing at an increasing rate. The modern era of minimally invasive, highly informative, neurological diagnostic imaging methods began with the introduction of x-ray computed tomography in the 1970s. More recently, positron emission tomography and single-photon emission computed tomography have been used extensively in research on normal and pathological brain function, and they are finding specific medical applications. Nuclear magnetic resonance methods are in widespread use for neurological diagnosis only a decade after they became available. Rapid development of new techniques based on the same principles, and implementable on clinical instruments with relatively minor modifications, will expand the range of nuclear magnetic resonance measurement capabilities considerably in the near future. These technological innovations and others yet to come have major implications for the practice of neurology. The most important one is an increase in relative value among clinical diagnostic skills of history taking and mental status examination, which will remain largely beyond the reach of technology.


Absence of measles, mumps, and rubella viral genomic sequences from multiple sclerosis brain tissue by polymerase chain reaction. We tested for measles, mumps, and rubella viruses in multiple sclerosis by polymerase chain reaction (PCR). Using RNA extracted from 19 multiple sclerosis and 8 control brain specimens, nested PCR was performed after reverse transcription (RT) of the RNA to cDNA using primer pairs directed against two regions in the genomes of measles and mumps viruses and one region in the rubella virus genome. Despite enhanced sensitivity of nested RT PCR, measles, mumps, and rubella viral genomic sequences were not found in any brain specimen.


Werdnig-Hoffmann disease and chronic distal spinal muscular atrophy with apparent autosomal dominant inheritance. We report on a family in which both Werdnig-Hoffmann disease (severe infantile-onset spinal muscular atrophy) and chronic distal spinal muscular atrophy occurred, with apparent autosomal dominant inheritance. The female proband clinically had Werdnig-Hoffmann disease and died at 10 months. In their second decade of life, the proband's father and his 2 brothers developed bilateral progressive atrophy and weakness of the hands and mild weakness in the distal parts of the legs. Their mother had no symptoms or signs of motor neuron disease but electromyography revealed distal denervation of the limbs. While the family studies suggest autosomal dominant inheritance, it is possible that the proband's condition was influenced by a maternally derived allelic or modifying trait.


Recurrent transverse myelitis, myasthenia gravis, and autoantibodies. A 45-year-old man with a longstanding diagnosis of myasthenia gravis presented with four episodes of transverse myelitis in 5 years. Each episode improved after treatment with steroids. Laboratory studies revealed no evidence of multiple sclerosis or a structural spinal lesion. He had antinuclear and anti-DNA antibodies and the HLA-A1, B8, DR3 haplotype known to be associated with certain autoimmune diseases. We propose an autoimmune cause for the recurrent episodes of myelitis.


Effects of age and gender on pharmacokinetics of cefepime. The effects of age and gender on the pharmacokinetics of cefepime were examined in 48 volunteers following administration of a single 1,000-mg intravenous dose. Male and female subjects were divided into four groups, each consisting of 12 subjects, according to their age and gender. The young subjects were between 20 and 40 years of age and elderly subjects were between 65 and 81 years of age. Serial blood and urine samples were collected from each subject and were analyzed for cefepime by validated high-pressure liquid chromatographic assays with UV detection. Key pharmacokinetic parameters were calculated by noncompartmental methods. There were no gender-related differences in elimination half-life (t1/2) and weight-normalized total body clearance (CLT), renal clearance (CLR), and steady-state volume of distribution (Vss). Statistically significant age-related effects were found for t1/2, CLT, CLR, and Vss parameters. In different study groups, Vss ranged from 0.21 to 0.24 liter/kg. The values for Vss were significant greater for elderly subjects than they were for young subjects. The cefepime t1/2 was significantly longer in elderly subjects (about 3 h) than that observed in young subjects (about 2.2 h). The mean values for CLT and CLR in the four study groups ranged from 1.11 to 1.56 and 0.99 to 1.44 ml/min/kg, respectively. In elderly subjects, the estimates for CLT and CLR were significantly lower than those observed in young subjects. Linear regression revealed good correlations between clearance values of cefepime and creatinine. The magnitude of age-related changes in the pharmacokinetics of cefepime is not significant enough to recommend dosage adjustment in elderly patients with kidney functions normal for their age.


Efficacy of erythromycin lactobionate for treating Pseudomonas aeruginosa bacteremia in mice. We induced endogenous Pseudomonas aeruginosa bacteremia by administering cyclophosphamide and ampicillin to specific pathogen-free mice fed P. aeruginosa. Using this model, we evaluated the efficacy of erythromycin lactobionate (EML) in treating P. aeruginosa bacteremia. Treatment with EML at 50 and 100 mg/kg of body weight per day twice a day for 14 days significantly increased the survival rate. The most effective dose was 100 mg/kg/day, with a survival rate of 80% compared with a 20% survival rate in the control. However, the administration of EML at 500 mg/kg/day rather decreased the survival rate. In a model of intravenous infection, treatment with EML at 100 mg/kg/day twice a day for 7 days before the bacterial challenge also enhanced the survival rate. EML levels in serum, liver, and stool were apparently lower than the MIC (512 micrograms/ml). These observations suggest that EML is effective against P. aeruginosa bacteremia despite a lack of specific activity for this pathogen. Although the protective mechanism is still unclear, it is possible that a subinhibitory level of EML may affect the virulence of P. aeruginosa and enhance the host defense system.


Dynamic interactions of biofilms of mucoid Pseudomonas aeruginosa with tobramycin and piperacillin. The dynamic interaction of planktonic and biofilm cells of mucoid Pseudomonas aeruginosa with tobramycin and piperacillin was investigated in a chemostat system. The results indicated that planktonic and young biofilm cells of the 2-day-old chemostat culture of P. aeruginosa were susceptible to killing by chemostat-controlled doses of either 250 micrograms of piperacillin per ml plus 5 micrograms of tobramycin per ml or 500 micrograms of piperacillin per ml plus 5 micrograms of tobramycin per ml. Complete eradication of the planktonic and young biofilm cells was observed after exposure of the cells to six chemostat-controlled doses of these antibiotic at 8-h intervals for 7 days. Regrowth of the organism was not observed after the termination of antibiotic therapy on day 7. A different picture was observed when antibiotic treatment was initiated on day 10 after inoculation. Viable old biofilm cells were reduced to approximately 20% after exposure to the chemostat-controlled doses of 500 micrograms of piperacillin per ml plus 5 micrograms of tobramycin per ml. Complete eradication of old biofilm cells could not be achieved, and regrowth of the organism occurred after the termination of antibiotic therapy. These data suggest that young biofilm cells of mucoid P. aeruginosa can be effectively eradicated with the combination of piperacillin and tobramycin, while old biofilm cells are very resistant to these antibiotics and eradication of old biofilm cells is not achievable with the chemostat-controlled doses of piperacillin and tobramycin used in this study.


Combined effect of fluconazole and recombinant human interleukin-1 on systemic candidiasis in neutropenic mice. The aim of the present study was to investigate the efficacy of treatment with a combination of fluconazole and human recombinant interleukin-1 alpha (IL-1 alpha) in normal or neutropenic mice with systemic Candida albicans infection. Six hours after intravenous injection of 5 x 10(4) CFU of C. albicans organisms, oral treatment twice daily with 2.5 or 10 mg of fluconazole per kg of body weight, a single intraperitoneal injection of 80 ng of IL-1, or a combination of the two was started. IL-1 had no influence on the antifungal activity of fluconazole in vitro or on the pharmacokinetics of fluconazole. For both normal and neutropenic mice, the number of C. albicans organisms cultured from the kidneys after 36 h of treatment was significantly lower in mice treated with IL-1 alone than in untreated animals. Treatment with fluconazole alone also significantly lowered the number of C. albicans organisms in the kidneys compared with that in untreated controls. In normal mice, the combination of fluconazole and IL-1 was not better than fluconazole alone. In neutropenic mice, combined treatment with IL-1 and 10 mg of fluconazole per kg led to significantly lower numbers of C. albicans organisms in the kidneys and the spleen than treatment with either agent alone. Although the precise mechanism by which IL-1 enhances resistance to infection is not clear, the additive effect of IL-1 and fluconazole in vivo indicates that combined therapy with immunomodulators and antifungal drugs is beneficial in immunocompromised mice with systemic fungal infections.


Practical computer-assisted dosing for aminoglycoside antibiotics. In principle, computer-assisted individualization of antibiotic dosing offers the prospect of better patient outcomes through improved dosing precision. In practice, however, the expertise in pharmacokinetics required to operate these programs has precluded their use by most physicians and pharmacists. We developed a computer program for individualization of dosing of aminoglycoside antibiotics under conditions in which access to experts in pharmacokinetics is impractical. The program is accurate, yet it requires less effort for data collection than previous drug dosing programs did. The program generates advice on a broad spectrum of topics, including dose adjustment, interpretation of measured drug concentrations in blood, and recommendations for monitoring drug concentrations. We tested its performance by prospectively comparing it with a clinical pharmacokinetic consultation service in a series of 78 consecutive patients. There were no differences in accuracy or bias in the prediction of drug concentrations. The rate of agreement between the program's dosing recommendations and those of the consultation service was 67 percent. This rate of agreement is typical of interexpert variation. In a stratified set of 24 of the 41 instances with significant disagreement regarding the recommended dose, experts ranked the program's recommendations as highly as those of the consultation service (95% confidence interval for difference in rank, -0.30 less than chi less than 0.47). The results suggest that expert systems can be coupled with pharmacokinetic dosing programs to deliver high-quality clinical recommendations for administration of antimicrobial agents.


Therapy of Rhodococcus equi disseminated infections in nude mice. Rhodococcus equi is a facultative, intracellular, gram-positive coccobacillus increasingly reported as an opportunistic pathogen in human immunodeficiency virus-positive patients. However, the optimal drug regimen for treating R. equi pulmonary or systemic infections is not yet known. Therefore, a model of intravenously infected nude mice with disseminated infection was created to study the efficacy of antibiotics alone or in combination as determined by the reduction of bacterial CFU per gram in the lungs and spleen after 4 and 11 days of treatment. The studied antibiotics possessing low MICs against R. equi strains were amikacin, ciprofloxacin, erythromycin, imipenem, minocycline, rifampin, and vancomycin. Vancomycin, imipenem, and rifampin were the most effective agents in monotherapy. On the other hand, amikacin, ciprofloxacin, erythromycin, and minocycline alone were not active in this model. The most active drug combinations were those including vancomycin. No antibiotic-resistant mutants were selected in vivo with treatment involving any drugs used alone or in combination. Although the treatment recommended until now for R. equi infections is rifampin plus erythromycin, this study suggests that antibiotic combinations which include vancomycin may be the most effective in vivo.


Teicoplanin versus vancomycin for prophylaxis of experimental Enterococcus faecalis endocarditis in rats. Teicoplanin was compared with vancomycin for the prophylaxis of experimental Enterococcus faecalis endocarditis in rats. Single intravenous doses of teicoplanin (7 mg/kg of body weight) or vancomycin (15 mg/kg) were given 30 min before bacterial challenge. Two strains of E. faecalis (309 and 1209) isolated from patients with endocarditis were tested. Bacterial inocula ranged from 10(4) (i.e., the inoculum infecting 90% of the control rats [ID90]) to 10(7) CFU/ml. The MICs and MBCs of teicoplanin and vancomycin were, respectively, 0.25 to greater than 128 mg/liter and 2 to greater than 128 mg/liter for strain 309 and 0.5 to greater than 128 mg/liter and 0.5 to greater than 128 mg/liter for strain 1209. Vancomycin prevented endocarditis only in 60% (strain 309) and in 87% (strain 1209) of rats challenged with the smallest bacterial-inoculum size (ID90), whereas teicoplanin prevented endocarditis in 100% of rats challenged with the same inoculum (strain 309; P = 0.05), in 87% of rats challenged with 10 times the ID90 (strain 309; P = 0.02), and in 95% of rats challenged with 100 times the ID90 (strain 1209; P = 0.0003). The combination of teicoplanin plus gentamicin (4 mg/kg) extended the protection to inocula 100 times the ID90 (strain 309; 96% of sterile animals) and 1,000 times the ID90 (strain 1209; 100% of sterile animals). Prevention of endocarditis was likely to be due to a prolonged inhibition of bacterial growth by sustained levels of teicoplanin in serum and not to bacterial killing. Indeed, teicoplanin did not exhibit any bactericidal activity either in vitro (time-kill curves) or in vivo (serum bactericidal activity). Teicoplanin proved to be superior to vancomycin in the prophylaxis of experimental E. faecalis endocarditis in rats.


Effects of magainins on ameba and cyst stages of Acanthamoeba polyphaga. Amebic keratitis produced by Acanthamoeba spp. is an increasingly important ocular infection in extended-use contact lens wearers. Problems associated with the infection are compounded by the lack of effective and well-tolerated chemotherapeutic agents. The magainins, a group of naturally occurring and synthetic membrane-active peptide compounds, have been shown to be active in vitro against a clinical isolate of Acanthamoeba polyphaga. Two magainins tested extensively had minimal inhibitory and minimal amebicidal values of 20 and 25 micrograms/ml for magainin MSI-103 and 25 and 40 micrograms/ml for magainin MSI-94, respectively. Both amebastatic and amebicidal activities are enhanced by combining the magainins with silver nitrate (200 micrograms/ml) and/or other marginally effective antimicrobial agents. These combinations have activity against both trophic and cystic stages in the Acanthamoeba life cycle and have promise as antimicrobial agents in the treatment of amebic keratitis.


Continuous intravenous versus intermittent ampicillin therapy of experimental endocarditis caused by aminoglycoside-resistant enterococci. We studied the efficacy of continuous intravenous infusion of ampicillin compared with that of intermittent administration of ampicillin alone or in combination with gentamicin for the therapy of highly aminoglycoside-resistant enterococcal experimental endocarditis. Rabbits were infected with a gentamicin-susceptible (MIC, 256 micrograms/ml) strain of Enterococcus faecalis or a strain of E. faecalis which was highly resistant to gentamicin in vitro (MIC, greater than 2,000 micrograms/ml). Administration of ampicillin by continuous intravenous infusion did not significantly enhance the killing of enterococci in vivo compared with that by intermittent administration of ampicillin for either the aminoglycoside-susceptible or the aminoglycoside-resistant strain. In combination with gentamicin, there were no significant differences in efficacies obtained with intermittent versus continuous intravenous infusion of ampicillin therapy for experimental endocarditis caused by either strain of E. faecalis.


High-performance liquid chromatographic method for potency determination of amoxicillin in commercial preparations and for stability studies. A reversed-phase column liquid chromatographic method was developed for the assay of amoxicillin and its preparations. The linear calibration range was 0.2 to 2.0 mg/ml (r = 0.9998), and recoveries were generally greater than 99%. The high-performance liquid chromatographic assay results were compared with those obtained from a microbiological assay of bulk drug substance and capsule, injection, and granule formulations containing amoxicillin and degraded amoxicillin. At the 99% confidence level, no significant intermethod differences were noted for the paired results. Commercial formulations were also analyzed, and the results obtained by the proposed method closely agreed with those found by the microbiological method. The results indicated that the proposed method is a suitable substitute for the microbiological method for assays and stability studies of amoxicillin preparations.


Impact of bioavailability on determination of the maximal tolerated dose of 2',3'-dideoxyinosine in phase I trials. The objective of this study was to determine the population pharmacokinetic parameters and the extent of absorption of 2',3'-dideoxyinosine, a nucleoside analog with activity against human immunodeficiency virus in vitro and in vivo, after oral and intravenous administration through the use of NON-linear Mixed Effects Modeling. The data were drawn from the pharmacokinetics section of an open-label, multicenter phase I study. One center administered ddI on a once-daily schedule. The other centers administered the drug once every 12 h. Drug was administered intravenously, and the plasma concentration-time profile was determined. Patients were then given the drug orally at twice the dose used in the intravenous portion of the study, and the pharmacokinetic profile was again determined. A 40-fold range of doses was examined. Forty-six human immunodeficiency virus-infected patients were studied. Concentrations in plasma were determined by high-pressure liquid chromatography. Clearance of the drug from plasma was 47.7 liters/h/70 kg of body weight. The terminal half-life was 1.4 h. The volume of distribution in the central compartment was 18.8 liters/70 kg. Absorption was rapid, with an absorption half-life of 0.52 h. Bioavailability with once-daily administration was 27%. For twice-daily administration, bioavailability rose to 36%. This difference was significant (P much less than 0.01). For doses of less than or equal to 5.1 mg/kg given every 12 h (10.2 mg/kg/day), bioavailability was 41%. We conclude that once-daily administration results in lower mean bioavailability, probably because of a saturation of the absorption process similar to that seen with acyclovir. This difference in bioavailability on the basis of the administration schedule explains the different short-term maximal tolerated doses identified in phase I trials of this agent.


Positive interaction of nikkomycins and azoles against Candida albicans in vitro and in vivo. Nikkomycins X and Z (NZ), competitive inhibitors of fungal chitin synthetase, were combined with azoles in a series of in vitro checkerboard assays to test for synergism against Candida spp. All combinations of nikkomycins and azoles tested resulted in marked synergistic activity against an isolate of Candida albicans, with fractional inhibitory concentration indices ranging from 0.016 to 0.28. No synergistic effect was demonstrable with isolates of C. tropicalis, C. parapsilosis, or C. krusei, though results for the latter two were suggestive of an additive effect. In survival models of mice infected intravenously with C. albicans, NZ administered singly in doses ranging from 5 to 50 mg/kg of body weight twice a day was able to delay the onset of mortality but showed no dose-response effect. The combination of NZ and the azole R 3783 administered orally in a ratio of 8:1 to 40:1 or greater (wt/wt) enhanced survival better than did the drugs given individually, but this effect was less evident for combinations involving fluconazole. In short-term organ load assays with outbred mice infected intravenously with C. albicans, high ratios of NZ to R 3783 reduced the CFU per gram in kidneys more significantly than did the drugs individually. Statistically significant reductions were not seen for short-term fungal burden assays using combinations of NZ and fluconazole in outbred mice or in inbred mice more susceptible to candidiasis. In a model of rat vaginal candidiasis, the combination of NZ and R 3783 administered either orally or vaginally was more effective than the drugs used singly. Thus, under certain conditions, combination therapy with nikkomycin and select azoles may offer promise for an increased therapeutic effect in candidiasis.


Effects of a human antiflagellar monoclonal antibody in combination with antibiotics on Pseudomonas aeruginosa infection. The in vivo activity of human immunoglobulin M monoclonal antibody IN-2A8, which is specific for flagellum type b of Pseudomonas aeruginosa, was evaluated in comparison to anti-O antigen (serotype B) MAb KO-2F2 and in combination with antibiotics. IN-2A8 showed stronger activity than KO-2F2 against subcutaneous infection in burned mice, while it was much less active against intraperitoneal infection in normal mice. In a burn infection model, IN-2A8 inhibited the increase of bacteria in skin lesions weakly and that in blood significantly, suggesting that it strongly suppressed bacterial spread to blood. The activity of IN-2A8 in combination with 10 antipseudomonal antibiotics against intraperitoneal infection was examined. Clear additive effect was observed with a combination of either carbapenem or aminoglycoside antibiotics in terms of mouse survival. The administration of an antibiotic, imipenem-cilastatin, simultaneously with or before that of IN-2A8 gave a combined effect, but the reverse order did not. The combination of IN-2A8 with imipenem-cilastatin decreased numbers of viable bacteria in the peritoneal cavity and blood and kept them low for a longer time than did either treatment alone. These results suggest that an antiflagellar monoclonal antibody would be effective against systemic infection in combination with some kinds of antibiotics.


Mycolic acid synthesis: a target for ethionamide in mycobacteria? Striking structural analogies exist between the two specific antimycobacterial drugs ethionamide (ETH) and isoniazid (INH), and they share several inhibitory properties in susceptible species of mycobacteria. The effect of ETH on mycolic acid synthesis was studied in whole cells and in cell extracts of various species, since this synthesis is one direct target for INH, as we recently demonstrated in cell extracts of Mycobacterium aurum. It was shown in the present study that there is not a direct relationship between ETH susceptibility and mycolic acid inhibition. This observation could explain the lack of cross-resistance between the two drugs. The presence of ETH disturbed mycolic acid synthesis in both resistant and susceptible mycobacteria. Synthesis of oxygenated species of mycolic acid was inhibited, while that of diunsaturated acids was either slightly altered or even increased. In contrast, INH inhibited the synthesis of all kinds of mycolic acids in the same way in all susceptible strains and had no effect on mycolic acid synthesis in resistant strains. In the presence of ETH, the unsaturated mycolic acid molecules presented a methyl end different from the usual one. These data strongly suggest that the normal unsaturated mycolic acid species are not the precursors of the oxygenated types. Moreover, they show that ETH probably acts early in the pathway leading to oxygenated mycolic acid.


Antimycoplasmal activities of new quinolones, tetracyclines, and macrolides against Mycoplasma pneumoniae. Fifty strains of Mycoplasma pneumoniae were tested for susceptibility to new quinolones, tetracyclines, and macrolides. Temafloxacin, ofloxacin, and ciprofloxacin possessed the most mycoplasmacidal activity against these organisms. The MBC for 50% of the strains (MBC50)-to-MIC50 ratio for each of these drugs was 4. The MBC50-to-MIC50 ratios for the tetracyclines and macrolides were markedly higher, within a range of 32 to 2,000. On the basis of these results, temafloxacin and ofloxacin might be promising antimicrobial agents for the treatment of mycoplasmal infection.


Antimicrobial susceptibilities of a Corynebacterium CDC group I1 strain isolated from a patient with endocarditis. We encountered a case of native valve endocarditis due to Corynebacterium CDC group I1 which was successfully controlled with antimicrobial agents alone. This organism and three other isolates of this group were susceptible to penicillin, vancomycin, and gentamicin. The combination of penicillin with subinhibitory concentrations of gentamicin resulted in a 1,000-fold decrease in CFU per milliliter at 24 h compared with penicillin alone. Augmentation of killing was noted also with vancomycin plus gentamicin but to a degree that did not meet strict criteria for bactericidal synergism.


Effects of antibiotics and other drugs on toxin production in Clostridium difficile in vitro and in vivo. In an attempt to understand more completely why patients treated with phenothiazines (chlorpromazine and cyamemazine), methotrexate, and certain antibiotics such as clindamycin have an increased risk of developing pseudomembranous colitis, the production of toxins A and B by Clostridium difficile in the presence of these drugs was measured in vitro as well as in vivo by using axenic mice. None of the drugs tested increased the production of toxins either in vitro or in vivo.


In vitro activity and susceptibility to hydrolysis of S-1006. The in vitro activity of S-1006, the active component of a new orally absorbed cephalosporin, S-1108, inhibited 90% of Staphylococcus aureus isolates at less than or equal to 2 micrograms/ml, 90% of group A, B, C, F, and G streptococci and Streptococcus pneumoniae isolates at less than or equal to 0.12 microgram/ml, and all Haemophilus influenzae isolates at less than or equal to 0.06 microgram/ml. Although 50% of the members of the family Enterobacteriaceae were inhibited by less than or equal to 2 micrograms of S-1006 per ml, Enterobacter spp. and Citrobacter freundii resistant to ceftriaxone were resistant to S-1006. The MICs of S-1006 for approximately 20% of Providencia, Proteus vulgaris, and Serratia isolates were 4 micrograms/ml. S-1006 was hydrolyzed by the plasmid TEM-3, TEM-5, PSE-1, and PSE-4 beta-lactamases and by the chromosomal beta-lactamase of Enterobacter and Morganella spp. and P. vulgaris.


Increased resistance to amikacin in a neonatal unit following intensive amikacin usage. Gram-negative isolates from blood and cerebrospinal fluid were monitored for 1 year before and for 1 year after the first-line aminoglycoside in a busy pediatric department was changed from gentamicin to amikacin. In the general pediatric wards, the switch to amikacin resulted in no change in resistance of nosocomial gram-negative infections to either amikacin (0% before and after) or gentamicin (23.9% [before] versus 26.5% [after]). In the neonatal unit, the switch to amikacin was followed by an outbreak of Serratia spp. that were commonly resistant to amikacin but susceptible to gentamicin. This outbreak abated spontaneously. In the year after the change in aminoglycoside usage, the resistance to amikacin of nosocomially acquired gram-negative infections increased from 7.6 to 27.7% (P less than 0.001), and the resistance to gentamicin decreased from 71.2 to 60.2% (P = 0.07). The increase in amikacin resistance of gram-negative bacilli other than Serratia spp. has persisted for more than a year after the introduction of amikacin as the sole aminoglycoside. The different effects observed in the two sections of the pediatric department may be related to the more intensive usage of aminoglycosides in the neonatal unit.


Quinolone accumulation in Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The accumulation of quinolones by Escherichia coli JF568, Pseudomonas aeruginosa PAO1, and Staphylococcus aureus ATCC 29213 was measured by a modified fluorometric assay (J. S. Chapman and N. H. Georgopapadakou, Antimicrob. Agents Chemother. 33:27-29, 1989). The quinolones examined were fleroxacin, pefloxacin, norfloxacin, difloxacin, A56620, ciprofloxacin, ofloxacin, and Ro 09-1168. In all three organisms, uptake was complete in less than 5 min and was proportional to extracellular quinolone concentrations between 2 and 50 micrograms/ml, which is consistent with simple diffusion. Washing cells with quinolone-free buffer decreased accumulation by up to 70% in E. coli and P. aeruginosa but not in S. aureus. Similarly, incubation with the uncouplers 2,4-dinitrophenol and carbonyl cyanide m-chlorophenylhydrazone increased accumulation up to fourfold in E. coli and P. aeruginosa, though not in S. aureus, suggesting endogenous, energy-dependent efflux. High quinolone hydrophobicity was generally associated with decreased accumulation in E. coli and P. aeruginosa (except in the case of pefloxacin) but was associated with increased accumulation in S. aureus (except in the case of difloxacin). Ciprofloxacin had the highest accumulation in E. coli and P. aeruginosa, while pefloxacin had the highest accumulation in S. aureus.


Liquid chromatographic determination of ampicillin in bovine and dog plasma by using a tandem solid-phase extraction method. The determination of ampicillin in plasma and serum by reversed-phase high-performance liquid chromatography with UV detection suffers from poor selectivity and sensitivity. Currently, the most common approach to overcoming these problems consists of improving the compound's detectability via pre- or postcolumn derivatization. In the method that we describe, however, enhanced selectivity is afforded by sample purification by a tandem solid-phase extraction method (ion-exchange and reversed-phase). This approach permits detection at wavelengths of as low as 210 nm, which results in enhanced sensitivity (detection limit, 0.01 microgram/ml). A second factor that affects selectivity is the addition to the chromatographic eluent of a crown ether to optimize the separation between ampicillin and polar endogenous plasma constituents. This combination of improved sample pretreatment and a more selective chromatographic system in conjunction with internal standardization forms the basis of a new assay for the quantitation of ampicillin in plasma. The overall recovery of ampicillin was 76.4% +/- 4.9% (n = 24), and the within-run and between-run coefficients of variation ranged from 1.6 to 7.2%. The method was applied to pharmacokinetic studies in cows and dogs after intramuscular or oral administration of the drug.


Evaluation of cefuroxime axetil and cefadroxil suspensions for treatment of pediatric skin infections. A randomized, single-blind, multicenter study was conducted to evaluate the safety and efficacy of cefuroxime axetil and cefadroxil suspensions for the treatment of skin or skin structure infections in 287 children. Each drug was given at a dosage of 30 mg/kg of body weight per day in two divided doses. Staphylococcus aureus and Streptococcus pyogenes, or a combination of the two, were the primary pathogens isolated from infected skin lesions. A satisfactory bacteriological response (cure or presumed cure) was obtained in 97.1 and 94.3% of children in the cefuroxime axetil and cefadroxil groups, respectively (P greater than 0.05). Satisfactory clinical responses (cure or improvement) were more likely to occur in cefuroxime axetil recipients than in cefadroxil recipients (97.8 versus 90.3%; P less than 0.05). Both regimens were equally well tolerated, with adverse events occurring in 7.9 and 6.1% of cefuroxime axetil and cefadroxil recipients, respectively. There were more patients who refused to take cefuroxime axetil (7 of 189) than there were who refused to take cefadroxil (0 of 98), but the difference was not statistically significant (P = 0.1). In this study, cefuroxime axetil was at least as effective as cefadroxil in resolving skin and skin structure infections in children.


Innovative endpoint determination system for antifungal susceptibility testing of yeasts. Fungal infections and antifungal resistance are increasingly recognized. Antifungal susceptibility testing remains unstandardized, and a particularly important problem is endpoint determination. In this paper we propose the yeast metabolic reduction of the tetrazolium salt 2,3-bis(2- methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetraz olium hydroxide (XTT) as a colorimetric endpoint which is quantitative and objective. Amphotericin B, fluorocytosine, and fluconazole dose-response curves were obtained, and a metabolic MIC could be determined by using precise criteria.


Susceptibility testing of clinical isolates of Methylobacterium species. Methylobacterium species represent a relatively new genus which is being increasingly isolated from cases of opportunistic infections. This study reports on 3 reference strains and 15 clinical isolates of Methylobacterium species. Susceptibility tests were performed by the agar dilution and commercial broth microdilution methods at both 30 and 35 degrees C. Readings were made at 24, 48, and 72 h. Incubation conditions of 48 h and 30 degrees C were found to be optimum. Both the agar dilution and broth microdilution methods gave equivalent results. Drugs tested and their MICs for 90% of isolates (in micrograms per milliliter) were as follows: amikacin, less than or equal to 1; gentamicin, 1; ciprofloxacin, 1; trimethoprim-sulfamethoxazole, 2/38; ceftriaxone, 16; and ceftizoxime, 16. The majority of our isolates were resistant to six other beta-lactam drugs tested. Nine of the 15 Methylobacterium isolates were beta-lactamase positive.


Correlation between in vitro antimicrobial susceptibilities and beta-lactamase plasmid contents of isolates of Haemophilus ducreyi from the United States. We determined the susceptibilities of 94 strains of Haemophilus ducreyi isolated in various municipalities in the United States between 1982 and 1989 to the following antimicrobial agents: amoxicillin-clavulanic acid, ceftriaxone, erythromycin, azithromycin, ciprofloxacin, ofloxacin, trimethoprim, and spectinomycin. Ceftriaxone (MIC, less than or equal to 0.008 micrograms/ml), azithromycin (MIC, less than or equal to 0.125 micrograms/ml), erythromycin (MIC, less than or equal to 0.125 micrograms/ml), ciprofloxacin (MIC, less than or equal to 0.25 micrograms/ml), and ofloxacin (MIC, less than or equal to 0.25 micrograms/ml) were highly active against all isolates. Amoxicillin-clavulanic acid (MICs, 0.25 to 8.0 micrograms/ml), trimethoprim (MICs, 0.06 to 16.0 micrograms/ml), and spectinomycin (MICs, 2.0 to greater than or equal to 32.0 micrograms/ml) were less active against these isolates. Isolates possessing the 5.7-MDa beta-lactamase plasmid were less susceptible to erythromycin, trimethoprim, and spectinomycin than were isolates possessing the 3.2-MDa beta-lactamase plasmid. The susceptibilities of plasmidless isolates to erythromycin, trimethoprim, and spectinomycin were distributed bimodally; the median MIC for the more susceptible plasmidless isolates corresponded to that for isolates with the 3.2-MDa plasmid, and the median MIC for the less susceptible plasmidless isolates corresponded to that for isolates with the 5.7-MDa plasmid. Thus, plasmid profiles may be valuable markers for geographical variations in antimicrobial susceptibilities of H. ducreyi strains that may indicate the relative efficacy of regimens for the treatment of chancroid. Of the regimens recommended by the U.S. Public Health Service for the treatment of chancroid, our results support the use of erythromycin, ceftriaxone, and ciprofloxacin, and perhaps ofloxacin, but suggest that amoxicillin-clavulanic acid and sulfamethoxazole-trimethoprim should be used with caution.


In vitro study of anticancer acridines as potential antitrypanosomal and antimalarial agents. The requirement for rational drug design in the search for new agents that are active against parasitic protozoa prompted our in vitro studies with a group of 9-anilinoacridines. In vitro growth assays with Trypanosoma lewisi identified a series of C-1' alkylaminoacridines which possess previously unreported potent growth-inhibitory activities against T. lewisi at a concentration range of 0.1 to 1 microM. In contrast, several 9-anilinoacridines that possess acridine ring NH2 substituents at C-3 and C-6 were inactive against T. lewisi, but they possessed strong activity against Plasmodium falciparum at a concentration range of 0.1 to 2.8 microM. In mammalian cells, amsacrine [4'-(9-acridinylamino)methanesulfon-m-anisidide] inhibits DNA topoisomerase II; however, amsacrine was only weakly active against T. lewisi. Such differences in the patterns of susceptibility of mammalian cells, T. lewisi, and P. falciparum to these 9-anilinoacridines may reflect enzyme differences between different parasites and mammalian cells that can be exploited by further improvements in drug design.


In vitro antifungal activities and in vivo efficacies of 1,3-beta-D-glucan synthesis inhibitors L-671,329, L-646,991, tetrahydroechinocandin B, and L-687,781, a papulacandin. The in vivo anti-Candida activities of 1,3-beta-D-glucan synthesis inhibitors L-671,329, L-646,991 (cilofungin), L-687,901 (tetrahydroechinocandin B), and L-687,781 (a papulacandin analog) were evaluated by utilizing a murine model of disseminated candidiasis that has enhanced susceptibility to Candida albicans but increased sensitivity for discriminating antifungal efficacy. DBA/2 mice were challenged intravenously with 1 x 10(4) to 5 x 10(4) CFU of C. albicans MY1055 per mouse. Compounds were administered intraperitoneally at concentrations ranging from 1.25 to 10 mg/kg of body weight twice daily for 4 days. At 6 h and 1, 2, 3, 4, 7, and 9 days after challenge, five mice per group were sacrificed and their kidneys were homogenized and plated for enumeration of Candida organisms (CFU per gram). Progressiveness of response trends and no-statistical-significance-of-trend doses were derived to rank compound efficacy. 1,3-beta-D-Glucan synthesis 50% inhibitory concentrations were determined by using a C. albicans (MY1208) membrane glucan assay. Candida and Cryptococcus neoformans MICs and minimal fungicidal concentrations were determined by broth microdilution. L-671,329, L-646,991, L-687,901, and L-687,781 showed similar 1,3-beta-D-glucan activities, with 50% inhibitory concentrations of 0.64, 1.30, 0.85, and 0.16 micrograms/ml, respectively. Data from in vitro antifungal susceptibility studies showed that L-671,329, L-646,991, and L-687,901 had similar MICs ranging from 0.5 to 1.0 micrograms/ml, while L-687,781 showed slightly higher MICs of 1.0 to 2.0 micrograms/ml for C. albicans MY1055. Lipopeptide compounds were ineffective against C. neoformans strains. Results from in vivo experiments comparing significant trend and progressiveness in response analyses indicated that L-671,329 and L-646,991 were equipotent but slightly less active than L-687-901, while L-687,781 was ineffective at 10 mg/kg. Fungicidal activities of L-671,329, L-646,991, and L-687,901 were observed in vivo, with significant reduction in Candida CFU per gram of kidneys compared with those in sham-treated mice at doses of > or = 2.5 mg/kg evident as early as 1 day after challenge.


Antimicrobial susceptibility testing of Bilophila wadsworthia by using triphenyltetrazolium chloride to facilitate endpoint determination. Initial susceptibility studies of Bilophila wadsworthia indicated significant resistance to several beta-lactam antibiotics, including imipenem and cefoxitin. NO beta-lactamase production was detected. However, some B. wadsworthia strains may grow as a heavy "haze" at up to the highest concentration of an antibiotic on standard antimicrobial agent-containing plates, and it is often difficult to determine the point at which conventional growth stops and haze growth begins. We investigated the nature of the haze growth of B. wadsworthia by using triphenyltetrazolium chloride (TTC) as an indicator of viability during antimicrobial susceptibility testing, by determining viability counts on antimicrobial agent-containing plates at various times, and by microscopically inspecting stained preparations of the growth on the control plate and the haze area. TTC MICs were determined by applying a TTC solution over the growth on plates inside the anaerobic chamber or within 5 min after exposure to air (aerobic TTC MICs). The haze growth reduced TTC in the chamber but not under aerobic conditions, whereas TTC was reduced by the conventional growth in both atmospheres. The aerobic TTC MICs correlated with the viability counts. Separated proteins resolved by polyacrylamide gel electrophoresis and isoelectric focusing showed TTC-reactive bands only when stained under anaerobic conditions, further demonstrating the sensitivity of TTC reduction to aerobic conditions. Microscopic examination of the haze growth indicated spheroplast formation. A new antibiogram for B. wadsworthia has been established by use of aerobic TTC endpoints; we believe that the lower MICs obtained with the TTC method are likely the ones that are clinically relevant and should be used in tests of B. wadsworthia. Also, we found that when the organisms were grown on pyruvate-containing medium, 87% of 56 strains tested were Beta-lactamase positive.


Platelet microbicidal protein enhances antibiotic-induced killing of and postantibiotic effect in Staphylococcus aureus. The interaction of bacteria with platelets at the cardiac valve surface represents a critical event in the induction of infective endocarditis. Platelets are thought to modulate induction or propagation of endocarditis via secretion of alpha-granule-derived platelet microbicidal protein (PMP) (a low-molecular-mass, cationic, heat-stable protein distinct from lysozyme). We studied representative PMP-susceptible and PMP-resistant Staphylococcus aureus isolates to determine their in vitro bacteriostatic and bactericidal susceptibilities to combinations of PMP plus antistaphylococcal antibiotics. PMP plus oxacillin exerted a synergistic bactericidal effect, in contrast to either agent alone, regardless of the intrinsic PMP susceptibility of the isolate tested. Exposure of S. aureus to PMP alone resulted in residual postexposure growth-inhibitory effects lasting from 0.9 to 1.8 h. Sequential exposure of S. aureus isolates to PMP for 30 min followed by exposure to either oxacillin or vancomycin (each at 10x the MIC for 120 min) resulted in a significant extension of the postantibiotic-effect duration compared with antibiotic exposure alone (P less than or equal to 0.05). Collectively, these findings indicate that PMP both enhances antibiotic-induced killing of S. aureus and increases the postantibiotic-effect duration in S. aureus.


Antibiotic susceptibility survey of Neisseria gonorrhoeae in Thailand. The antibiotic susceptibilities of Neisseria gonorrhoeae isolates obtained from patients attending sexually transmitted disease clinics in Cholburi and Bangkok, Thailand, were determined by agar dilution. Some 28.2% of isolates produced beta-lactamase. A total of 97.9% of beta-lactamase-positive and 51% of beta-lactamase-negative isolates tested were resistant to penicillin (MICs, greater than or equal to 2 micrograms/ml), 70% of isolates tested were resistant to tetracycline (MICs, greater than or equal to 2 micrograms/ml), and 91% of isolates tested were susceptible to spectinomycin (MICs, less than or equal to 64 micrograms/ml). The MICs for 90% of isolates for the other drugs tested were 2 micrograms/ml for erythromycin, 2 micrograms/ml for cefoxitin, 1 micrograms/ml for cefuroxime, 0.125 micrograms/ml for cefpodoxime, 0.06 micrograms/ml for cefotaxime, 0.25 micrograms/ml for ceftazidime, 0.03 micrograms/ml for ceftizoxime, 0.03 micrograms/ml for ceftriaxone, 0.03 micrograms/ml for cefixime, 0.06 micrograms/ml for aztreonam, 0.008 micrograms/ml for ciprofloxacin, 0.125 micrograms/ml for norfloxacin, and 0.075 micrograms/ml for ofloxacin. Fewer than 1.5% of isolates were resistant to the extended-spectrum cephalosporins tested. Some 0.3% or fewer isolates were resistant to broad-spectrum cephalosporins, fluoroquinolones, or the monobactam aztreonam. Antibiotic resistance among N. gonorrhoeae isolates from Cholburi and Bangkok in May 1990 appeared to be primarily limited to penicillin and tetracycline, which are no longer used to control gonorrhea. Spectinomycin, which has been in general use against gonorrhea in Thailand since 1983, has dwindling utility, with resistance at a level of 8.9%.


Resistance to cefotaxime and seven other beta-lactams in members of the family Enterobacteriaceae: a 3-year survey in France. During the second quarter each of 1988, 1989, and 1990, a French collaborative study group, including 12 university hospital laboratories, surveyed the resistance to beta-lactams of clinical isolates from hospitalized patients: consecutively, 10,641, 10,692, and 9,382 isolates were tested. The distribution of bacterial species over time was similar in each laboratory. The susceptibilities of microorganisms to amoxicillin, ticarcillin, cephalothin, cefoxitin, cefotaxime (CTX), ceftazidime (CAZ), aztreonam (ATM), and imipenem (IPM) were measured by the disk diffusion method in accordance with the recommendations of the Antibiogram Committee of the French Society for Microbiology. Five reference strains were included for quality control. Extended-spectrum beta-lactamases were detected by the synergistic effect of the combination of clavulanic acid-amoxicillin with CTX, CAZ, and ATM in the double-diffusion test. A synergistic effect with CTX, CAZ, and ATM was detected for 1.5% of all strains, mainly those of Klebsiella pneumoniae (13.3%). For this species, the synergy test enabled the detection of roughly 50% of the resistant strains misclassified as susceptible on the basis of interpretative standards. Extended-spectrum beta-lactamases disseminated in 1990 in most enterobacterial species but at a low frequency. Important variations in the percentages of resistant strains were observed in terms of bacterial species, hospitals, and wards. However, when the total number of strains was considered, the percentages of resistance to newer beta-lactams remained low.


Bacteriostatic and bactericidal activities of gentamicin alone and in combination with clarithromycin against Mycobacterium avium. The inhibitory activity of gentamicin against Mycobacterium avium depended on the pH of the medium, and the broth-determined MICs for 90% of strains were 5.0 micrograms/ml at pH 7.4, 9.5 micrograms/ml at pH 6.8, and greater than 16.0 micrograms/ml at pH 5.0. The MBCs were two- to eightfold higher than the MICs. The combined effect of gentamicin and clarithromycin was additive, and the MICs and MBCs of each drug were either the same as those in the single-drug tests or reduced twofold.


In vitro activity of MC-352, a new 16-membered macrolide. The in vitro activity of MC-352, 3,4'-dideoxy-5-O-mycaminosyltylonolide, was compared with those of erythromycin, clarithromycin, and rokitamycin. The MC-352 MIC90 (MIC for 90% of isolates) for erythromycin-susceptible Staphylococcus aureus and Staphylococcus epidermidis was less than or equal to 1 microgram/ml, similar to those of the other agents. The MC-352 MIC50 for erythromycin-resistant S. aureus was 2 micrograms/ml, similar to that of rokitamycin. The MC-352 MIC90 (0.12 micrograms/ml) for Streptococcus pyogenes was similar to those of erythromycin and clarithromycin and superior to that of rokitamycin, and the MC-352 MIC90 for group B, C, and G streptococci was 0.25 microgram/ml. MC-352 and clarithromycin had an MIC90 of 0.12 microgram/ml for Streptococcus pneumoniae. Erythromycin-susceptible Enterococcus faecalis was inhibited by MC-352 at 1 microgram/ml, but the MIC for constitutively erythromycin-resistant isolates was greater than 16 micrograms/ml. Legionella pneumophila was inhibited by less than or equal to 0.25 microgram/ml. MC-352 was the most active agent against Bacteroides fragilis, with an MIC90 of 8 micrograms/ml, and was more active than the other agents against Haemophilus influenzae, with an MIC90 of 4 micrograms/ml. Moraxella spp. were inhibited by MC-352 at less than or equal to 0.25 microgram/ml. The MIC90 for Escherichia coli, Klebsiella pneumoniae, and Salmonella, Shigella, Yersinia, Enterobacter, Citrobacter, and Serratia spp. was greater than or equal to 32 micrograms/ml. MC-352 was bactericidal for S. pyogenes and S. pneumoniae, and its activity was not altered by human serum.


Increased rate of isolation of penicillin-resistant Streptococcus pneumoniae in a children's hospital and in vitro susceptibilities to antibiotics of potential therapeutic use. The isolation of Streptococcus pneumoniae with both high and intermediate resistance to penicillin has increased in our institution since 1989 to an average of 12.1% of all isolates. We determined the susceptibilities of 95 isolates (34 susceptible to penicillin, 42 intermediate in resistance to penicillin, and 19 resistant to penicillin) to 16 antimicrobial agents of potential use in the treatment of disease caused by S. pneumoniae. Susceptibility to penicillin was determined by broth macrodilution with Mueller-Hinton broth supplemented with 5% lysed horse blood. Isolates were classified as highly resistant when the MIC was greater than or equal to 2.0 micrograms/ml, intermediate in resistance when the MIC was between 0.1 and 1.0 microgram/ml, and susceptible when the MIC was less than 0.1 microgram/ml. Fifteen of 19 isolates found to be highly resistant to penicillin were recovered from the middle ear of children. None of the isolates recovered from cerebrospinal fluid was highly resistant to penicillin. Fifteen of these isolates highly resistant to penicillin were found to be serogroup 6. Susceptibilities to other antibiotics were determined by the agar dilution method with Mueller-Hinton agar containing 5% lysed horse blood and an inoculum of 10(4) CFU per spot delivered by a replicator device. The MIC for 90% of isolates increased with increasing penicillin resistance for all antibiotics tested, except chloramphenicol, ciprofloxacin, rifampin, and vancomycin. Regardless of the classification of penicillin resistance, all isolates were classified as susceptible to cefotaxime, cefpirome, cefpodoxime, clarithromycin, imipenem, rifampin, and vancomycin on the basis of National Committee for Clinical Laboratory Standards interpretive guidelines. Interpretation of susceptibilities on the basis of currently available guidelines is difficult in that susceptibility guidelines applicable specifically to S. pneumoniae are not available.


Identification by DNA sequence analysis of a new plasmid-encoded trimethoprim resistance gene in fecal Escherichia coli isolates from children in day-care centers. In our ongoing studies of trimethoprim resistance (Tmpr) in day-care centers (DCC), we have shown a high rate of fecal colonization with Tmpr Escherichia coli and, using total plasmid content analysis, have shown that this is due to a diversity of strains. In the present study, we analyzed 367 highly Tmpr (MIC, greater than or equal to 2,000 micrograms/ml) isolates of E. coli from 72 children over a 5-month period and found at least 83 distinct plasmid patterns, indicating that at least 83 strains were involved. Several strains were particularly common in a given DCC, including one found in 61% of children with Tmpr E. coli; these common strains usually persisted within a DCC for several months. Colony lysates were hybridized with gene probes for dihydrofolate reductases (DHFR) types I, II, III, V, and VII; 21% hybridized under stringent conditions, and all of these were with type I (17%) or type V (4%) probes. Tmpr was cloned from a probe-negative Tmpr transconjugant, and an intragenic probe was prepared from this clone. Approximately 21% of the Tmpr E. coli strains (76 isolates) in the DCC were found to have this new gene, 74 of which were in one DCC. The DNA sequence of this gene was determined, and the predicted amino acid sequence was shown to have between 32% and 39% identity with the amino acid sequences for types I, III, V, VI, and VII and the partial sequence of type IV and approximately 26% identity with types IX and X DHFR. This confirms the uniqueness of this gene, which has tentatively been named dhfrxii, and its translation product, DHFR type XII.


Antifungal susceptibility testing of Candida spp. by relative growth measurement at single concentrations of antifungal agents. The relative growth (percentage of growth relative to control growth) of 496 isolates representing six Candida species was assessed as a means of determining in vitro susceptibilities of the isolates in microdilution plate wells containing single concentrations of each of seven antifungal agents. The relative growth data were highly reproducible. With flucytosine and amorolfine they correlated well with MICs, but for an azole antifungal agent, terconazole, they did not correlate with MICs. Distributions of relative growth percentages for different Candida spp. showed significant differences in species susceptibility to individual agents. For example, C. albicans was less susceptible than the other species to amorolfine; C. parapsilosis isolates were particularly susceptible to terbinafine; and C. glabrata, C. guilliermondii, and C. krusei isolates were less susceptible than C. albicans to fluconazole and ketoconazole but equally susceptible as or more susceptible than C. albicans to itraconazole. Differential patterns of susceptibility to individual azole antifungal agents were noted for some individual strains as well as for Candida spp.


Temperature-dependent in vitro antimicrobial activity of four 4-quinolones and oxytetracycline against bacteria pathogenic to fish. The in vitro antimicrobial activities of oxolinic acid, flumequine, sarafloxacin, enrofloxacin, and oxytetracycline against strains of bacteria pathogenic to fish (Aeromonas salmonicida subsp. salmonicida, atypical A. salmonicida, Vibrio salmonicida, Vibrio anguillarum, and Yersinia ruckeri) were determined at two different incubation temperatures, 4 and 15 degrees C, by a drug microdilution method. The main objective of the study was to examine the effect of incubation temperature on the in vitro activities of 4-quinolones and oxytetracycline against these bacteria. When tested against A. salmonicida subsp. salmonicida, all of the quinolones examined had MICs two- to threefold higher at 4 degrees C than at 15 degrees C. Similarly, 1.5- to 2-fold higher MICs were recorded for all of the quinolones except sarafloxacin at 4 degrees C than at 15 degrees C when the drugs were tested against V. salmonicida. In contrast to those of the quinolones, the MICs of oxytetracycline were two- to eightfold lower at 4 degrees C than at 15 degrees C against all of the bacterial species tested. Of the antimicrobial agents tested against the bacterial species included in the study, enrofloxacin was the most active and oxytetracycline was the least active. Sarafloxacin was slightly more active than flumequine and oxolinic acid, especially against oxolinic acid-resistant A. salmonicida subsp. salmonicida strains.


Teicoplanin metabolism in humans.

Teicoplanin metabolism in humans. Teicoplanin, a lipoglycopeptide antibiotic, consists of five major components (A2-1 through A2-5), one hydrolysis component (A3-1), and four minor components (RS-1 through RS-4). All the major components contain an N-acyl-beta-D-glucosamine, but they differ in the lengths and branchings of their acyl-aliphatic chains. Previous studies with radiolabeled teicoplanin in rats and humans have shown that the drug is eliminated by the renal route and that metabolic transformation is very minor, about 5%. A possible metabolic transformation of teicoplanin into A3-1 was also suggested. In the present study in humans, two metabolites (metabolites 1 and 2; 2 to 3% of total teicoplanin) were isolated after intravenous administration of radiolabeled teicoplanin. After purification, their structures were determined by fast atom bombardment mass spectroscopy and 1H nuclear magnetic resonance spectroscopy on the basis of the well-known correlations established in this field, and they were found to be new teicoplaninlike molecules, bearing 8-hydroxydecanoic and 9-hydroxydecanoic acyl moieties. This metabolic transformation is likely due to hydroxylation in the omega-2 and omega-1 positions for metabolites 1 and 2, respectively, of the C-10 linear side chain of component A2-3. This might explain the low extent of metabolism of teicoplanin if we consider that only component A2-3 has a linear chain that is susceptible to such oxidation.


Inhibition of rabies virus transcription in rat cortical neurons with the dissociative anesthetic ketamine. In a previous study (B. P. Lockhart, H. Tsiang, P. E. Ceccaldi, and S. Guillemer, Antiviral Chem. Chemother. 2:9-15, 1991), we demonstrated an antiviral effect of the general anesthetic ketamine for rabies virus in neuronal cultures and in rat brain. This report describes an attempt to determine at what level ketamine acts on the rabies virus cycle in rat cortical neuron cultures. Immunofluorescence and [35S]methionine labelling of infected neurons showed that ketamine (1 to 1.5 mM) inhibited viral nucleoprotein and glycoprotein syntheses. Northern (RNA) blots of total RNA from drug-treated neurons, hybridized with 32P-labelled oligonucleotide probes for rabies virus nucleoprotein, matrix protein, and glycoprotein genes, showed a marked reduction (5- to 11-fold) in the levels of rabies virus mRNAs, relative to those in untreated neurons. No significant change in the levels of cellular beta-actin mRNA were detected in ketamine-treated cells. A similar antiviral effect was observed with MK-801; however, no inhibition of rabies virus synthesis was observed with the general anesthetic chloral hydrate. The antiviral effect was not complete; a time-dependent recovery of viral transcription and rabies virus protein synthesis was observed, but no infectious virus was released into the culture supernatant. The lack of any modification of cellular protein or mRNA synthesis by ketamine suggests an antiviral mechanism acting at the level of rabies virus genome transcription.


Antibacterial activity of RU44790, a new N-tetrazolyl monocyclic beta-lactam. RU44790 belongs to a new class of synthetic monocyclic beta-lactam antibiotics which feature a bioisosteric tetrazole moiety instead of the more classical acidic functions at the N-1 position of the beta-lactam ring. Its antibacterial activity was evaluated against some 900 strains and was compared with those of other recent beta-lactam derivatives, especially aztreonam. RU44790 is endowed with potent activity against gram-negative bacteria. At less than or equal to 0.6 micrograms/ml, RU44790 inhibited 90% of all strains of the family Enterobacteriaceae with the exception of Citrobacter spp. (MIC for 90% of strains tested, 1.2 micrograms/ml). The activity was similar to that of aztreonam against strains that are normally susceptible to expanded-spectrum cephalosporins. On the other hand, the new compound was 10 to 100 times more potent than aztreonam and most of the other antibiotics tested against enterobacteria that produce chromosome-encoded or plasmid-mediated extended-spectrum beta-lactamases. Pseudomonas aeruginosa isolates were equally susceptible to both monobactams. RU44790 was inactive against staphylococci and had only marginal activity against streptococci (MIC for 50% of strains tested, 2.5 micrograms/ml). RU44790 was highly resistant to hydrolysis by various beta-lactamases, particularly cephalosporinases such as P99. The latter enzyme was also inhibited by the compound. RU44790 showed a high affinity for penicillin-binding protein 3 of Escherichia coli. The results suggest that RU44790 has good potential in the treatment of infections caused by gram-negative microorganisms.


Orally administered cefpodoxime proxetil for treatment of uncomplicated gonococcal urethritis in males: a dose-response study. An open-label, dose-response study of cefpodoxime proxetil (CPD), an expanded-spectrum cephalosporin, was conducted with 58 males with uncomplicated Neisseria gonorrhoeae infections with single doses of 600, 400, 200, 100, or 50 mg of CPD administered orally by tablet. CPD eradicated N. gonorrhoeae in all 50 evaluable patients (10 per group) at all doses studied. Eight of the isolates eradicated were beta-lactamase-producing organisms. Two patients reported three side effects, nausea, vomiting, and diarrhea, which were mild and resolved without intervention or sequelae. There were no clinically remarkable drug-related changes in vital signs or clinical laboratory assays. Results show that single oral doses of CPD are an effective and well-tolerated treatment for uncomplicated N. gonorrhoeae infection in males at doses as low as 50 mg.


Analysis of vancomycin time-kill studies with Staphylococcus species by using a curve stripping program to describe the relationship between concentration and pharmacodynamic response. Mono- and biexponential killing curves for vancomycin over a 2- to 50-micrograms/ml concentration range were generated for 11 Staphylococcus aureus isolates and 12 coagulase-negative Staphylococcus species in the logarithmic phase of growth. Nonlinear least-squares regression of the initial growth rate and disappearance were not significantly different for lower or higher concentrations of vancomycin in broth.


Long-term tolerance and efficacy of 3'-azidothymidine and 3'-fluorothymidine treatment of asymptomatic monkeys infected with simian immunodeficiency virus. Macaques chronically infected with simian immunodeficiency virus were treated with zidovudine (20 mg/kg of body weight per day for 9 weeks) or 3'-fluorothymidine (5 mg/kg of body weight per day for 9 weeks or three doses of 2 mg/kg per day for 24 days). Hematological changes in the treated animals included macrocytic anemia and leukopenia. Determination of antiviral effects in this model requires improved assay methods.


Pharmacokinetics of concomitantly administered foscarnet and zidovudine for treatment of human immunodeficiency virus infection (AIDS Clinical Trials Group protocol 053). Foscarnet and zidovudine (ZDV) pharmacokinetic parameters were not altered in five patients receiving 14 days of concomitant therapy. Foscarnet clearance in plasma averaged (+/- standard deviation) 0.16 +/- 0.03 and 0.13 +/- 0.05 liter/h/kg of body weight in the absence and presence of ZDV. ZDV parameters were also not significantly altered, with a mean (+/- standard deviation) oral clearance of 2.7 +/- 1.0 and 2.6 +/- 0.8 liter/h/kg for the 2 study days, respectively.


Effects of squalene epoxidase inhibitors on Candida albicans. The relationship between sterol biosynthesis inhibition, membrane integrity, and cell growth inhibition in Candida albicans was examined for five squalene epoxidase inhibitors. The compounds were the thiocarbamates tolnaftate and tolciclate and the allylamines naftifine, terbinafine, and SDZ 87-469. All compounds inhibited sterol biosynthesis, with the concentrations that caused a 50% decrease in the total sterol-to-squalene ratio ranging from less than or equal to 0.01 microM for terbinafine and SDZ 87-469 to 500 microM for tolnaftate. At 100 microM, the compounds also caused up to a 30% release of intracellular [14C]aminoisobutyric acid. With terbinafine and SD2 87-469, aminoisobutyric acid release further increased in cells grown at concentrations that inhibited ergosterol biosynthesis. It is suggested that inhibition of ergosterol synthesis may render the C. albicans membrane susceptible to further damage, including direct damage from squalene epoxidase inhibitors.