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Biomedical subjects

J Robinson

Publications and source records attributed to J Robinson.

At least 379 records · Page 21Linked to original sources
PubMed1989

Apparent Smith-Lemli-Opitz syndrome and Miller-Dieker syndrome in a family with segregating translocation t(7;17)(q34;p13.1).

We describe a family in which one male infant presented with Miller-Dieker syndrome and four male relatives had a phenotype similar to the Smith-Lemli-Opitz (SLO) syndrome. High resolution cytogenetic analysis on the child with Miller-Dieker syndrome showed 46,XY,-17,+der17t(7;17)(q34:p13.1). Paternal chromosomes showed a balanced translocation: 46,XY,t(7;17)(q34:p13.1). The paternal grandmother had a history of multiple miscarriages, and a paternal uncle had two sons who died neonatally. Chromosomes on these children and their father had originally been reported as normal. There was also a paternal cousin to the father of the propositus who had had two sons with similar clinical findings. A diagnosis of SLO syndrome was considered. Image enhancement techniques on previous suboptimal preparations on these four children documented the subtle unbalanced translocation 46,XY,-7,+der7t(7;17)(q34:p13.1). Subsequent high resolution analysis on one of these four children who was still living confirmed this chromosome constitution. It is postulated that these apparent SLO cases may represent a contiguous gene syndrome in which SLO or a separate entity closely mimicking the syndrome in included.

Abnormalities, Multiple↗
PubMed1989

Tuberculin sensitivity and an interaction of leucocyte and plasma factors involving fibrinogen.

Lysates of blood leucocytes from strong tuberculin-positive reactors contained smaller particles of insoluble protein-rich material than did similar preparations from negative donors. The phenomenon was dependent on the presence of small quantities of plasma in the original leucocyte suspensions: when this was removed or replaced by serum both groups of donors produced particles of the smaller size. When the experiments were repeated in the presence of 125I-fibrinogen, larger particle size was found to be associated with an increased proportion of radioactivity becoming firmly bound to the insoluble material. These findings are likely to reflect differences in the levels of procoagulant, proteolytic enzymes or associated activities in the cells or plasma of the two groups.

Adult↗
PubMed1989

Temporal relationships among estrus, body temperature, milk yield, progesterone and luteinizing hormone levels, and ovulation in dairy cows.

Estrous cycles of 10 postpartum cyclic Holstein cows were synchronized using prostaglandin f(2alpha) (PGF(2alpha)) given twice 12 d apart to study the relationship of the onset of estrus, body temperature, milk yield, luteinizing hormone (LH) and progesterone concentration to ovulation. Blood samples and body temperatures (vaginal and rectal) were taken every 4 h until ovulation, starting 4 h prior to the second PGF(2alpha) treatment. All cows were observed for estrus following the second administration of PGF(2alpha). Ultrasound scanning of the ovaries commenced at standing estrus and thereafter every 2 h until the disappearance of the fluid filled preovulatory follicle (ovulation). Two cows failed to ovulate and became cystic following the second PGF(2alpha) treatment. The remaining eight cows exhibited a decline in progesterone to <1.0 ng/ml within 28 h, standing estrus and a measurable rise (> 1.0 degrees C) in vaginal but not rectal temperature, and ovulated 90 +/- 10 h after the second PGF(2alpha) treatment. Onset of standing estrus, LH peak and vaginal temperature were highly correlated (P<0.05) with time of ovulation (0.82, 0.81 and 0.74, respectively). Intervals to ovulation tended to depend upon parity. Pluriparous (n = 4) and biparous (n = 4) cows ovulated within 24 and 30 +/- 3 h from the onset of standing estrus; 22 and 31 +/- 2 h from the LH peak; and 22 and 27 +/- 3 h from peak vaginal temperature (mean +/- standard error of the mean), respectively. The results indicated that the onset of standing estrus and rise in vaginal temperature are good practical parameters for predicting ovulation time in dairy cattle.

Journal Article↗
PubMed1989

Human urine mutagenicity study comparing cigarettes which burn or only heat tobacco.

Cigarette smokers have been reported to void urine which is more mutagenic, as measured in the Ames bacterial mutation assay, than urine voided by non-smokers. Condensate from the mainstream smoke of a cigarette which heats, but does not burn tobacco (test cigarette) showed no evidence of mutagenicity in a battery of in vitro genotoxicity assays under conditions in which condensate from the mainstream smoke of cigarettes that burn tobacco was mutagenic. The objective of this study was to determine whether the absence of mutagenic activity observed in the in vitro assays would be reflected in the urine of smokers of the test cigarette. 72 subjects (31 smokers and 41 non-smokers) were enrolled in a 6-week study, with the smokers randomly divided into 2 groups. The study was designed as a double crossover, with each smoker smoking both test (tobacco-heating) and reference (tobacco-burning) cigarettes. This design allowed each smoker to serve as his or her own control while at the same time allowing comparisons between groups of non-smokers and smokers of both test and reference cigarettes. 24-h urine samples were collected twice a week and concentrated using XAD-2 resin. Urine concentrates were tested in Ames bacterial strains TA98 and TA100, with and without metabolic activation and with and without beta-glucuronidase/aryl sulfatase. Individuals who smoked the test cigarette voided urine which was significantly less mutagenic than that voided when they smoked reference cigarettes. The mutagenicity of urine from smokers who smoked the test cigarette and non-smokers did not differ under any of the assay conditions used in this study.

Animals↗
PubMed1989

Strain-dependency of procarbazine-induced testicular toxicity.

Three strains of rat were used to examine strain-dependency of procarbazine-induced testicular toxicity. CCFHB and CCFY1 outbred albino rats and inbred PVG piebald variegated rats were treated weekly with procarbazine (200 mg/kg/dose x 4). Fifty-six days later, the rats were killed and reproductive parameters evaluated. Strain-related differences in body, testis, prostate, seminal vesicle weights, testis sperm, intratesticular testosterone, and [125I]hCG binding to testicular LH receptors were observed. Although treatment with procarbazine affected testis function in all strains, significant interactions occurred between treatment and strain. LH receptor binding and stem-cell survival were more severely affected in the inbred strain than in outbred strains. Serum testosterone increased in the outbred strain but decreased in the inbred strain, generating an interaction that obscured possible main effects. Significant strain-related differences in within-group variances demonstrated that measurements were more variable in the outbred strains than in the inbred strain. Testes of the inbred strain appeared to be more sensitive to the effects of procarbazine than those of the outbred strains. These data illustrate two important toxicologic phenomena: differences in response variability and differences in target-organ sensitivity, both of which were explained by genetic variability.

Animals↗
PubMed1989

Measuring the heaviness of smoking: using self-reported time to the first cigarette of the day and number of cigarettes smoked per day.

Two simple self-report measures have been used to assess the heaviness of smoking, 'number of cigarettes per day' (CPD) and 'time to the first cigarette of the day' (TTF). Little attention, however, has been given to the precise method of scoring this information. Using biochemical indicators of heaviness of smoking (alveolar carbon monoxide and cotinine), we explore the optimum data transformations for regression analysis and categorical analysis. We suggest a four category scoring scheme for both time to the first cigarette of the day (less than or equal to 5, 6-30, 31-60 and 61+ min) and average daily consumption of cigarettes (1-10, 11-20, 21-30, 31+ cigarettes) as the most powerful and practical categorical scoring of these variables. Due to possible ceiling effects on biochemical measures, we suggest using logarithmic transformations of CPD or TTF for regression or correlation analyses.

Adolescent↗
PubMed1989

Eyelid opening in preterm neonates.

The frequency and patterns of eyelid opening were examined in a group of neonates (gestational age 24-35 weeks). Observations were spread over the 24 hour period to obtain a complete pattern of events. Mean eyelid closure was 74%. When babies were grouped by gestational age, however, differences became apparent, babies of less than 26 weeks having their eyes shut for only 55% of observations compared with 93% at 28 weeks. Trend analysis confirmed that eyelid closure reached a peak at 28 weeks. Neonates exposed to a day/night regimen, opened their eyes significantly more than those exposed to continuous illumination. We suggest that frequency of eyelid opening may be related both to the infant's developmental state (postmenstrual age) and the illumination of the neonatal unit. Frequency of eyelid opening should therefore be considered when calculating the ocular light exposure of preterm neonates.

Aging↗
PubMed1989

Validation of a photographic method of measuring corneal diameter.

A photographic method for measuring corneal diameter using the Medical-Nikkor f200 mm lens is described. Measurements were compared with those obtained by calipers (46 eyes of 25 patients) and by placing a ruler either near the eye (123 eyes of 64 patients) or on the nose (98 eyes of 55 patients). Over all we found good correlation between photographic and caliper measurements (r = 0.94). No significant correlation was found between photographic measurements and estimates made with the ruler either near the eye or on the nose (r = 0.65 and 0.31 respectively). Modifications to our system are suggested which may provide an accurate, simple, non-invasive method of measuring corneal diameter in ophthalmic clinics.

Adult↗
PubMed1989

The peptidergic innervation of the developing mesenteric vascular bed in the rat.

We have followed the development of perivascular nerve fibres using antisera to substance P, calcitonin gene related peptide, neuropeptide Y and vasoactive intestinal polypeptide in the mesenteric vascular bed of developing Sprague-Dawley rats. The pattern and density of innervation appeared to be determined by one week of age. The pattern of innervation by SP- and CGRP-positive fibres was similar. The pattern of innervation by neuropeptide Y-containing fibres was distinct from that of SP and CGRP. The VIP-positive fibre plexus was sparse and irregular compared with the others examined. The density of innervation by all fibre types was highest in the jejunal arteries.

Animals↗
PubMed1989

Reducing severe aggressive and self-injurious behaviors with functional communication training.

Functional communication training is a behavioral intervention that incorporates a comprehensive assessment of the communicative functions of maladaptive behavior with procedures to teach alternative and incompatible responses. In two studies severe aggressive and self-injurious behaviors exhibited by two adult men with mental retardation were reduced through the implementation of functional communication training. In both studies, these reductions came after years of less successful nonaversive and aversive interventions and generalized across staff, new environments, and increasing task demands. The role of this training as a refinement of the traditional differential reinforcement of other behavior and as an alternative to the use of aversive interventions was discussed.

Adult↗
PubMed1988

Prospective study of an inverse relationship between maternal glycosylated hemoglobin and serum alpha-fetoprotein concentrations in pregnant women with diabetes.

A hypothesized inverse relationship between the concentration of glycosylated hemoglobin and serum alpha-fetoprotein was observed in a prospective study of 39 pregnant women with insulin-dependent diabetes as well as seven pregnant women with diabetes who did not require insulin (r = -0.434, p less than 0.002). No similar correlation was found among a selected population of healthy pregnant women (r = -0.129). Because the level of glycosylated hemoglobin in pregnancy correlates with poor outcome, including the occurrence of fetal anomaly, it may be important to quantify glycosylated hemoglobin in pregnancies with low alpha-fetoprotein levels. These results also suggest that the maternal concentration of glycosylated hemoglobin can be used to adjust serum alpha-fetoprotein values before their interpretation in the screening of pregnant women with diabetes.

Diabetes Mellitus, Type 1↗
PubMed1988

An antibacterial and antiviral powdered soft-drink base.

Soft-drink powdered mixtures have been developed which are bactericidal against a range of enteric bacteria and Staphylococcus aureus and which kill some enteric viruses in vitro. These mixtures could be used to help reduce risks of water-borne diarrhoeal illnesses, and as the basis for oral rehydration solutions, which would resist bacterial contamination after their preparation, to treat patients with diarrhoeal dehydration.

Anti-Bacterial Agents↗
PubMed1988

Delayed effects of doxorubicin on spermatogenesis and endocrine function in rats.

Doxorubicin was administered to adult male Wistar rats (1 mg/kg body weight, three times per week, for one, two, three, or four weeks) in order to examine testicular and reproductive endocrine toxicity 56 days after treatment. Doxorubicin treatment produced persistent dose-related reductions in testis, epididymis, and seminal vesicle weights, but did not alter ventral prostate weight. Testis and serum testosterone levels were not significantly affected by treatment, but serum LH was increased after treatment, and binding of iodinated hCG to testicular LH receptors was reduced. Serum FSH was elevated by the two lower total administered doses, but was not different from controls after treatment with the two higher total doses. There was clear histologic evidence of dose-dependent damage to the seminiferous tubules, which was reflected by decreased testicular and epididymal sperm content and by reductions in the stem-cell survival index. These results indicate that doxorubicin produces significant and persistent damage to the endocrine and spermatogenic compartments of the testis.

Animals↗
PubMed1988

Pediatric Symptom Checklist: screening school-age children for psychosocial dysfunction.

The Pediatric Symptom Checklist (PSC) is a 35-item screening questionnaire that is completed by parents and designed to help pediatricians in outpatient practice identify school-age children with difficulties in psychosocial functioning. The current study assessed the validity of the PSC by screening 300 children in two pediatric practices, a middle-class group practice and an urban health maintenance organization. Validity was established by comparing the results of PSC screening of 48 children with in-depth interview assessments and pediatricians' ratings. Results indicate that the PSC has a specificity of 0.68 and a sensitivity of 0.95. The screening process was well accepted by parents and pediatricians. Several children whose pediatricians' ratings had indicated adequate functioning were identified by the PSC as having substantial psychosocial dysfunction and requiring further evaluation.

Child↗
PubMed1988

Pharmacokinetics and tolerance of lomefloxacin after sequentially increasing oral doses.

The pharmacokinetics of five dose levels of lomefloxacin (100, 200, 400, 600, and 800 mg) were examined in a single-dose, double-blind, placebo-controlled study involving 40 subjects. There were eight subjects in each group: five received active drug and three received placebo; each subject was given only one dose. All subjects completed the study, and lomefloxacin was well tolerated at all doses. No drug crystals were noted in the urine at 3 and 6 h after the dose. The mean maximum concentration in serum (Cmax) ranged from 1.11 to 7.46 micrograms/ml for the 100- to 800-mg doses, respectively, and the AUC increased proportionally with the dose. The mean time to Cmax (Tmax) values averaged 64.8 +/- 28.8 min. The elimination half-life and plasma clearance averaged 7.7 +/- 0.52 h and 259 +/- 37 ml/min, respectively. Mean concentrations in urine were highest during the first 4 h after the dose and ranged from 104 to 713 micrograms/ml following the 100- and 800-mg doses, respectively. Concentrations above 20 micrograms/ml in urine were observed in most subjects over 24 h at the three lower doses and averaged over 120 micrograms/ml during the 12- to 24-h interval at the 400-mg dose, thus supporting once-per-day dosing. Excretion rates from urine and the cumulative amount excreted increased in a dose-related fashion. Renal clearance decreased moderately at the higher doses. Thus, lomefloxacin was well tolerated, and dose proportionality was demonstrated by most pharmacokinetic parameters. The 400-mg dose produced concentrations in plasma and urine above the MIC for susceptible pathogens.

4-Quinolones↗
PubMed1988

Maternal diabetes in rats. I. Effects on placental growth and protein turnover.

The developmental growth of the rat placenta was investigated between days 14 and 21 of gestation in normal control, gestational-diabetic, established-diabetic, and insulin-maintained-diabetic mothers. While established-diabetic mothers were hyperglycemic for 2 wk before and throughout the pregnancy, gestational-diabetic mothers were only hyperglycemic for the second half of pregnancy. Daily insulin replacements successfully restored normoglycemia. The wet weight and protein content of control placentas increased linearly between days 14 and 21. Although placentas from diabetic animals were initially smaller, placentomegaly was found at full term. Placental glycogen concentrations were also markedly increased in all diabetic animals. These changes were largely prevented by insulin replacement. The changes in placental size during normal development and in association with the diabetic state were explained by measuring placental rates of protein turnover (in vivo). In normal placentas, protein synthetic and degradative rates progressively declined over the last week of gestation. Because synthesis rates were unchanged in placentas of diabetic mothers, it appears that the differences in placental size primarily arise from alterations in protein degradation.

Animals↗
PubMed1988

Enterotoxigenic Escherichia coli in Central Australia: diagnosis using cloned and synthetic nucleic acid probes.

Feces from 169 children admitted with diarrhea to Alice Springs Hospital, were screened for enterotoxigenic E. coli (ETEC) using specific DNA probes. E. coli which hybridized with probes for ST-P, ST-H and LT were confirmed by bioassay for toxin production. Fifty children were shown to excrete ETEC. The probes for LT correlated well with bioassay; however, probes for ST-H and ST-P hybridized with more E. coli than were shown to produce toxin by bioassay. When probing for ST was repeated using a synthetic oligonucleotide probe, only those specimens which were bioassay-positive hybridized with the probe.

DNA↗