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Biomedical subjects

R Glass

Publications and source records attributed to R Glass.

At least 55 records · Page 3Linked to original sources

Summary of labour and obstetric audit by microcomputer.

A microcomputer is used directly by the clinician, immediately after delivering a baby, to produce a summary letter to the referring physician and for the case notes. The programme is easy to use, and accepted by a wide range of medical users. In addition to producing a summary, the information is added to the obstetric data base, which may be interrogated by a computer novice. The system is now used to produce yearly obstetric audits of the Queen Victoria Medical Centre.

Australia↗

Conservation of amino acid sequence of VP8 and cleavage region of 84-kDa outer capsid protein among rotaviruses recovered from asymptomatic neonatal infection.

Within the past few years, rotavirus strains were recovered from four discrete prolonged outbreaks of infection in newborn nurseries in which affected infants failed to develop significant symptoms. The virus strains recovered from each outbreak belonged to a different human rotavirus serotype and thus each of the four human rotavirus serotypes was associated with asymptomatic infection of neonates. Marked conservation of sequence was observed among the fourth genes of the nursery rotavirus strains in a previous study using RNA X RNA hybridization, while a different conserved set of fourth gene sequences was identified among virulent human rotaviruses representing the four known serotypes. In the present study, this sequence dimorphism was further evaluated by comparing the sequence of the region of the fourth gene of virulent and asymptomatic human rotaviruses that codes for the VP8 protein, downstream cleavage sites, and the NH2 terminus of VP5. The corresponding sequences of a simian rotavirus were also determined. The fourth segment (+) strand RNA has a 5' conserved nontranslated sequence of nine nucleotides and encodes a VP8 protein of 240 amino acids in human rotavirus strains and 241 amino acids in simian rotavirus strains. Human and simian rotaviruses exhibit many similarities in this region of their genome, including identical NH2-terminal amino acid sequences, conservation of arginine at the two trypsin cleavage sites, and the position of a cysteine residue. Alignment of amino acid sequences of the VP8 protein, the downstream cleavage region, and the NH2 terminus of VP5 of asymptomatic and virulent human rotavirus strains indicates a high degree of homology (96% or more) among the asymptomatic viruses (serotypes 1, 2, 3, and 4), while homology between asymptomatic strains and virulent viruses is considerably less (68-72%). A high degree of conservation of amino acid sequence (92-97%) is also observed among three of the virulent strains (serotypes 1, 3, and 4). At 48 positions in the protein sequence of VP8, the cleavage region, and the NH2 terminus of VP5, an amino acid is conserved among asymptomatic rotaviruses, while a different amino acid is conserved among virulent rotaviruses. Notably, three of these differences are located within the cleavage region between VP8 and VP5. These findings suggest that the fourth genes of virulent and asymptomatic human rotavirus strains represent two lines of divergent evolution from a common ancestor. Also, it is possible that this sequence dimorphism may be responsible in part for the difference in virulence between these two groups of human rotaviruses.

Amino Acid Sequence↗

Identification of enterotoxigenic Escherichia coli in patients with diarrhea in Asia with three enterotoxin gene probes.

A total of 984 enterotoxigenic Escherichia coli (ETEC) and 733 non-ETEC isolated from patients with diarrhea in Asia (one isolate per patient) were examined for homology with radiolabeled fragments of DNA encoding heat-labile toxin (LT) or heat-stable toxin of porcine (ST-P) or human (ST-H) origin. A total of 246 ETEC that produced LT and ST as determined by the Y-1 adrenal and suckling mouse assays were homologous with the LT probe. Of these 246 LTST ETEC, 156 (63%) were homologous with the ST-H, 46 (19%) were homologous with the ST-P, and 44 (18%) were homologous with both probes. A total of 401 LT ETEC were homologous with the LT probe. Of 337 ST ETEC identified by the suckling mouse assay, 244 (72%) were homologous with the ST-H, 84 (25%) were homologous with the ST-P, and 9 (3%) were homologous with both probes. None of the 733 isolates that were non-enterotoxigenic as determined by the Y-1 adrenal and suckling mouse assays was homologous with genes coding for enterotoxin. Four isolates (not included among the 984 ETEC examined) that were initially considered to produce LT because sterile culture supernatants produced rounding of Y-1 adrenal cells were not homologous with the LT probe. The sterile culture supernatants of these four isolates caused rounding after 8 h and subsequent destruction after 24 h of Y-1 adrenal tissue cultures. This effect was not inhibited by convalescent human cholera antiserum, Swiss Serum Institute cholera antitoxin, or antiserum to purified LT. These isolates were also negative in the Biken test previously used to identify LT-producing E. coli. The DNA hybridization technique with three enterotoxin gene probes was developed as a specific technique to identify ETEC in large numbers of specimens in Asia.

Animals↗

Immune responses to measles and smallpox vaccinations in malnourished children.

Children with different levels of nutritional status were studied to determine their immune response to, and complications from, immunization with live measles vaccine and lyophilized smallpox vaccine. Two hundred forty-one children between the ages of 5 months and 9 years were examined to assess their nutritional status at the time of immunization. Sero-conversion was defined as a hemagglutination-inhibition titer to measles virus, of greater than or equal to 1:20 6 to 8 weeks after vaccination in initially sero-negative children. Of 111 initially sero-negative children 94% had an adequate immune response, shown by sero-conversion. Of 193 children without a smallpox vaccinationscar 97% were successfully immunized against smallpox. These rates of immune response were independent of age, sex, and nutritional status of the children. The geometric mean titer rise to measles immunization of groups, whose nutritional status was normal (greater than 90% of median weight for age), mildly (75 to 90%), moderately (60 to 75%), or severely (less than 60%) malnourished were 7.5, 8.8, 7.9, and 7.9, respectively. Malnutrition did not affect the children's ability to develop adequate immune response to measles of smallpox vaccine, and there were no major complications during the 8-week period of follow-up. Since measles is a very severe disease, which in malnourished children can carry a case fatality rate as high as 50%, malnutrition should be a prime indication for measles immunization, and certainly not a contraindication.

Aging↗

Luteinizing hormone--releasing hormone levels in human plasma: a radioimmunoassay method.

A sensitive double-antibody radioimmunoassay, developed to measure luteinizing hormone--releasing hormone (LHRH) levels in fetal brain tissues, has been modified to quantitate LHRH in unextracted plasma samples. Pure, synthetic LHRH was iodinated with 125I for tracer and was also used as standard. The antibody utilized was specific for LHRH and did not cross react with other hypothalamic or pituitary hormones. The separation of free from antibody-bound tracer was performed by dextran-coated charcoal. The sensitivity of the assay was 2.5 pg/tube. The intra-assay and interassay coefficients of variation were 5.9 and 6.1% for 50 pg/ml and 11.8 and 14.9% for 25 pg/ml samples. Recovery of known amounts of LHRH added to plasma samples that had no detectable hormone was 96.4 +/- 8.8%. Whether these samples were previously prepared and kept frozen at -20 degrees C or freshly prepared, the recovery of LHRH was consistent and quantitatively stable in each assay. Serial determinations of LHRH in plasma obtained from ovulatory volunteers averaged between 20.5 +/- 2.1 pg/ml in the follicular phase and 19.4 +/- 4.5 pg/ml in the luteal phase. At midcycle, coincident with the luteinizing hormone surge, LHRH levels averaged 17.6 +/- 4.4 pg/ml.

Antibodies↗

Meperidine surveillance in an outpatient department: the recognition of misuse and its control.

The identification of two patients who were misusing meperidine prescribed in a hospital prompted the establishment of a surveillance system to examine the possible extent of the problem of prescription narcotic abuse. All outpatient prescriptions for meperidine in a six-month period were reviewed and 17 high users were identified who were considered to be at greatest risk of misuse; they received 55% of all meperidine dispensed from the OPD pharmacy. These persons obtained their prescriptions primarily through the emergency room, they rarely saw the same physician twice, and 12 of them carried a diagnosis of sickle cell disease. Among these patients, four cases of definite abuse were identified. Interventions aimed at promoting continuity of care to the high users led to a 66% reduction in meperidine prescribed to this group in the emergency room and to a shift in their care to the clinics. Establishment of a registry for narcotic surveillance is a first toward recognition of outpatient drug abuse. Limiting prescribing privileges to the physician responsible for a patient's long-term care can further decrease this risk.

Drug and Narcotic Control↗

Development of departmental promotion guidelines.

In making optimum use of its faculty, a medical school department should ensure that each faculty member has a clear understanding of what is expected of him and what will be evaluated when he is considered for reappointment or promotion. A set of departmental promotion guidelines which are available to all faculty can serve both these ends. In addition to defining the nature of the work which will be evaluated and stressing that performance quality is important, such guidelines should make explicit the various ways in which the work will benefit the department, the medical school, and the discipline. The guidelines can be used at the time of promotion, but they should also contribute to an ongoing evaluation of faculty work by the administration and by the faculty themselves.

Achievement↗

Inaccuracy of house staff in reading throat cultures.

The low prevalence of streptococcal pharyngitis in our pediatric clinic during a normally high-prevalence period encouraged us to examine the accuracy of throat culture readings made by the house staff. Six pediatric residents processed 256 cultures, which were then reinterpreted by a microbiologist. The residents consistently underread the cultures, failing to identify 68 (60%) of 112 with beta-hemolysis and 23 (58%) of 40 with a zone of bacitracin inhibition. This inaccuracy in interpretation of throat cultures emphasizes the physician's need to periodically reassess these skills.

Child↗

Histamine and peptic ulcer disease: histamine methyltransferase activity in gastric mucosa of control subjects and duodenal ulcer patients before and after surgical treatment.

Histamine methyltransferase (HMT) activity was determined by a modified isotope assay in biopsy specimens from gastric mucosa of control subjects, duodenal ulcer patients and after various gastric operations. Enzymic activity of male control subjects who were 'healthy' with respect to their upper gastrointestinal tract was 70.4 +/- 12.8 pmol/(min x mg protein). In male duodenal ulcer patients HMT-activity was significantly lowered by 15%; following selective vagotomy with pyloroplasty a significant increase of 14% was observed as compared to controls. The difference between values before (59.9 +/- 13.3) and after (80.4 +/- 11.7) this operation was highly significant (p less than 0.001). Experiments in a small number of patients showed that after other modifications of vagotomy elevated HMT-activities were also found, whereas after resection procedures such changes of enzymic activity did not occur. According to these results the low gastric HMT-activity of duodenal ulcer patients could play a role in the pathogenesis of a chronic peptic ulcer by being responsible for reduced histamine inactivation and - as a consequence - enhanced acid secretion. Furthermore, vagotomy seemed to influence acid secretion in human subjects not only by direct effects on the parietal cells, but also by an activation of histamine catabolism. One patient, who despite complete vagotomy showed both no reduction in acid secretion and a low gastric HMT-activity, may be the representative of a new population of peptic ulcer patients.

Duodenal Ulcer↗

Serum calcitonin-lowering effect of magnesium in patients with medullary carcinoma of the thyroid.

The effect of magnesium chloride or magnesium sulfate infusion on circulating levels of immunoreactive calcitonin (iCT) was evaluated on nine occasions in three patients with metastatic medullary carcinoma of the thyroid. One patient was normocalcemic and had normal circulating levels of immunoreactive parathyroid hormone (iPTH), one patient was hypocalcemic and had surgical hypoparathyroidism, and one patient had mild to moderate hypercalcemia associated with bone metastases. The basal serum iPTH levels were undetectable in the latter two patients. In every instance magnesium administration produced a rapid and striking fall in circulating iCT and usually a detectable fall in serum calcium. During the hypermagnesemic state, serum iPTH fell from normal to undetectable in the patient with normal parathyroid function, while serum iPTH levels remained undetectable in the hypoparathyroid patient and in the patient with hypercalcemia associated with bone metastases. The results of these studies indicate that: (a) contrary to what has been reported in normal experimental animals, magnesium administration lowers circulating iCT in human subjects with thyroid medullary carcinoma and (b) the calcium-lowering effect produced by magnesium in patients with medullary carcinoma may, in part at least, be due to a redistribution of body calcium that is not mediated by the actions of either parathyroid hormone or clacitonin.

Aged↗