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Biomedical subjects

M Robertson

Publications and source records attributed to M Robertson.

At least 163 records · Page 9Linked to original sources
PubMed1989

Residential instability in adolescent inpatients.

The case records of 225 randomly selected adolescent psychiatric inpatients were reviewed to determine prevalence of residential instability. The study also examined the demographic, family composition, life event, and behavior characteristics associated with residential instability. Approximately 30% of the sample had experienced a high rate of residential instability (i.e., from 5 to 20 domicile moves). Analyses indicated that residential instability was associated with a set of characteristics that included caregiver neglect, caregiver abuse, parental separation, multiple hospitalizations, lower IQ, indices of poor impulse control, and antisocial behavior. The possible contribution of residential instability to treatment resistance and the development of antisocial behaviors in some adolescents is discussed.

Adolescent↗
PubMed1989

Induction of alpha-amylase inhibitor synthesis in barley embryos and young seedlings by abscisic Acid and dehydration stress.

An endogenous alpha-amylase inhibitor was found to be synthesized in embryos of developing barley grain (Hordeum vulgare cv Bonanza). Accumulation of this protein occurred late in development (stage IV), at the same time that endogenous abscisic acid (ABA) showed a large increase. The inhibitor could be induced up to 23-fold in isolated immature embryos (stage III) by culture in ABA. Precocious germination was also blocked in stage III embryos by ABA. Dehydration stress on the isolated immature embryos also induced higher levels of the inhibitor and ABA. An even greater response to dehydration stress was observed in young seedlings, where inhibitor content increased 20-fold and ABA increased 80-fold during water stress. The high degree of correlation between ABA and inhibitor contents in in situ embryos, dehydrated embryos and young seedlings, as well as the increase in inhibitor caused by exogenously applied ABA to isolated embryos, suggests that increased alpha-amylase inhibitor synthesis in response to dehydration stress is mediated by ABA.

Journal Article↗
PubMed1988

White blood cell aplasia associated with thymoma.

A limited number of cases of acquired hypoplastic neutropenia or pure white blood cell aplasia (PWCA) associated with thymoma have been reported, in contrast to the well-documented association of pure red blood cell aplasia and thymoma. The mechanism of the aplasia in these disorders is unclear. The authors report a case of PWCA (with total absence of all granulopoietic elements in the bone marrow) in a patient with metastatic spindle cell thymoma, in which suppression of autologous granulocyte-macrophage colony-forming units by the patient's serum could be demonstrated. This finding suggests a humoral autoimmune mechanism for the pathogenesis of PWCA in this patient and lends support to the possibility that all hematologic phenomena associated with thymoma may have an autoimmune basis.

Aged↗
PubMed1988

Relationship between bioassay and radioimmunoassay measurement of prolactin in the IPL rat, a hypoprolactinemic rat strain.

IPL (Institut Pasteur, Lyon) nude, hypoprolactinemic rats exhibit delayed puberty and a complete lack of lactation. To characterize the secretion of circulating forms of prolactin (PRL) of these rats, PRL concentrations were measured in serum and pituitaries of males and females under various physiological conditions. Two assay methods, a radioimmunoassay (RIA) and a sensitive bioassay (NB2BA) were employed. Normal rats of the Sprague-Dawley strain were tested simultaneously, as controls. The pituitary content of PRL, estimated either by RIA or by NB2BA, in IPL nude males and females was similar to that of normal male and female rats. On the contrary, serum PRL levels of IPL male rats, measured by RIA or NB2BA, were significantly reduced when compared to normal rats. In both groups, there was a close correlation between the results obtained by the two methods, the NB2BA estimates being higher. However, the NB2BA/RIA ratio was significantly decreased in serum from IPL nude rats compared to controls, indicating that the circulating form of PRL was less bioactive in this group. Castrated male rats injected with estradiol showed sharply increased PRL values as estimated by RIA or NB2BA. The increase was greater (35-fold) in IPL nude rats then in normal rats (9-fold), but these increases resulted in serum PRL levels being similar in the two groups. However, the NB2BA/RIA ratio remained significantly reduced in IPL nude rats. In female rats, PRL was measured during different physiological states: estrus, diestrus, proestrus at 1000, 1200, and 1600 h and Days 1 and 21 of gestation and 2 days postpartum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Abnormalities of copper in Gilles de la Tourette syndrome.

The Gilles de la Tourette syndrome is a disorder whose etiology and pathogenesis are little understood. The number of biochemical abnormalities described in this disorder is minimal. Ten of a total of 80 patients were found to have an abnormally low serum copper. A report is presented on two patients who consented to further detailed investigation and in whom copper radioisotope studies were carried out. Both exhibited abnormalities of copper handling, in that we observed an abnormally fast disappearance of copper from the plasma and an abnormally slow uptake by the liver. The rates of intestinal absorption and urinary excretion were normal. We did not identify an abnormal site of sequestration of the metal in the body.

Adult↗
PubMed1987

The morphology of the right ventricular outflow tract after percutaneous pulmonary valvotomy: long term follow up.

Twenty nine patients (19 male, mean (SD) age 6.25 (0.5) years (range 0.16-15 years] with typical pulmonary valve stenosis were treated by balloon dilatation of the pulmonary valve. They were studied by echocardiography before the procedure, immediately after it, and at follow up (mean (SD) 10.2 (5.6) months, n = 18). The morphology of the pulmonary valve, the right ventricular-pulmonary artery gradient, and ratio of the systolic to diastolic endocardial dimensions (infundibular ratio) were examined. No patient had pulmonary regurgitation before the study. The valve gradient was significantly reduced (47%) from a mean (SD) of 72 (31) to 37 (23) mm Hg with no short term change in cardiac index after dilatation with a balloon with a mean (SD) diameter that was 118 (10.8)% of the valve annulus. The infundibular ratio was unchanged by the procedure (0.49 (0.11) (n = 21) before dilatation and 0.47 (0.14) (n = 16) after dilatation). In twenty seven patients the commissure of the pulmonary valve was seen to be torn after dilatation. Two patients with bicuspid valves had flail leaflets. Doppler examination at follow up showed mild pulmonary insufficiency in all 29 patients; the mean (SD) valve gradient (31 (+/- 21) mm Hg) at follow up was no different from the gradient found immediately after the procedure and infundibular ratio (0.58 (0.15) was not abnormal. These data indicate that commissural tears are the primary mechanism of valve disruption and demonstrate that the dynamic right ventricular outflow tract obstruction relaxes and gradient reduction persists at follow up.

Adolescent↗
PubMed1986

The humoral antibacterial response of Drosophila adults.

Hemolymph from a normal adult Drosophila melanogaster lacks factors that block the growth of Escherichia coli, but hemolymph from a fly previously inoculated with Enterobacter cloacae inhibits bacterial growth. Antibacterial activity appears within two hours after inoculation, and is still detectable sixty days later. Activity is potent, and can be detected in as little as a quarter of the hemolymph from a single inoculated male fly. After inoculation, at least eight new polypeptides not of bacterial origin appear in hemolymph with a time course similar to the appearance of antibacterial activity; these are called Antibacterial Response Polypeptides, or ARs. The most prominent polypeptides are AR24, AR22, and AR19 with molecular weights of about 24, 22, and 19 kilodaltons (kd). Other bands with as much as 75 kd and as little as 5 kd were also found. Electrophoresis of active hemolymph under non-denaturing conditions, and isoelectric focusing separate several protein species that block bacterial growth (Antibacterial Proteins, or ABs); one AB is neutral (AB7.1) and three are basic (AB8.7, AB9.0 and AB9.2). Two dimensional gels show that AR24, AR22 and AR19 have pIs identical to the basic antibacterial proteins. Radiolabelling experiments proved that the ARs were synthesized de novo after bacterial inoculation. ARs in six species of Drosophila showed fundamentally similar electrophoretic patterns.

Animals↗
PubMed1986

Moderate-dose vincristine infusion in refractory breast cancer.

Continuous infusion of vincristine at the maximally tolerated infusion dosage of 0.5 mg/m2/day for 5 days has been investigated in 15 patients with refractory breast cancer. Infusion courses were repeated every 3 weeks in the absence of disease progression or prohibitive toxicity. Progressive disease was observed in 14 patients. A partial response lasting 2 months occurred in a patient with pulmonary and skin metastases who had previously received vincristine by bolus injection. Toxicity consisted primarily of mild neurotoxicity of similar degree to that expected with bolus injection. Thrombocytopenia occurred, but was uncommon. The cumulative response rate at this dosage level (2/16, 13%) in our phase I-II trials indicates very limited clinical activity of vincristine infusion in advanced, refractory metastatic breast cancer.

Adult↗