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Biomedical subjects

M Robinson

Publications and source records attributed to M Robinson.

At least 325 records · Page 18Linked to original sources

Analysis of human peripheral blood mononuclear cells bearing Fc receptors for the three major immunoglobulin isotypes.

Fluorochrome-labeled, human immunoglobulins (Igs) were used to characterize peripheral blood mononuclear cell (PBMC) subsets that had Fc receptors (FcRs) for the three major isotype classes, IgG, IgA and IgM. Relatively high concentrations of these Igs were needed to saturate FcRs. However, by a number of criteria, competition assays in particular, isotype-specific FcR binding was shown. In vivo bound Ig was directly measured by anti-Fc class-specific F(ab)2 antibodies. With the exception of monocytes, where a mean of 19% had in vivo bound IgG, only small percentages of other PBMC subsets had any type of in vivo bound Ig. Studies done on a large group of normal individuals revealed that approximately 27% of all PBMCs had gamma, 24% alpha, and 23% microFcRs. Dual fluorescence assays were performed to determine the gamma, alpha, and microFcR status on T, B, NK cells and on monocytes. The majority of staining for gamma, alpha, and microFcRs was accounted for by the numerically largest subfraction, the T cells. However, when FcR status was determined for each subset virtually all had either gamma, alpha, or microFcRs--94% of CD2+, 98% of CD4+, 73% of CD8+, 100% of CD19+, 100% of CDw19+, 92% of Leu 7+, and 61% of Leu 11+ cells. All three FcRs were expressed within each subset. Of interest, a small percentage of unfractionated and monocyte-depleted PBMCs coexpressed one of three pairs of FcRs, either alpha and gamma, alpha and mu, or mu and gamma.

Antigens, Differentiation↗

Screening devices for diminished cognitive capacity.

This study compares three commonly used tests to detect organic mental disorders: the Mini-Mental State (MMS), Cognitive Capacity Screening Examination (CCSE), and Tachistoscope (T-Scope). Ninety-seven medical-surgical inpatients at the Mount Sinai Hospital referred for psychiatric consultation had a Missouri Mental Status Examination performed by a psychiatrist who also rated the patients' organic mental disorder as "none," "mild," "moderate," or "severe." The CCSE, MMS, and T-Scope, respectively, showed: sensitivity--0.54, 0.52, 0.68; specificity--0.85, 0.76, 0.79; and positive predictive value--0.83, 0.74, 0.79. False negatives occurred more often among those patients with mild organic mental disorders with all instruments (p = 0.05), while the T-Scope could not be administered in 27% of the patients. Screening instruments with increased acceptability, sensitivity, and specificity need to be developed to identify a potentially life-threatening disorder.

Adult↗

The response of the pig kidney to the combined effects of cisplatin and unilateral renal irradiation.

Seven mature Large White female pigs, approximately 10 months of age received a single dose of cis-dichlorodiammineplatinum(II), c-DDP (2.5 mg/kg body weight). Prior to, and 4 weeks after c-DDP administration, individual kidney glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured by [99mTc]DTPA and [131I]hippuran renography. Of the 5 pigs surviving the c-DDP treatment most exhibited a reduction in both GFR and ERPF; the mean reduction in GFR (36.2 +/- 18.9%) was more pronounced than that for ERPF (12.6 +/- 19.4%). However, the difference in the severity of the impairment in these two parameters was not significant (p greater than 0.55). Haematocrit, haemoglobin and red blood cell counts were markedly reduced 14 days after c-DDP infusion, and despite some recovery evident 21 days after treatment, all three haematological parameters were still reduced 28 days after c-DDP administration. The right kidneys of these 5 animals, plus 5 pigs which did not receive c-DDP, were irradiated with a single dose of 11.9 Gy of 60Co gamma-rays. Individual kidney GFR and ERPF was routinely measured up to 24 weeks after irradiation. Pigs in which only the right kidney was irradiated showed a marked increase in both GFR and ERPF values 2 weeks after irradiation. This was followed by a decline in function with a reduction of 50% in terms of ERPF 16 weeks after irradiation. Values then showed some evidence of a recovery in function. There was a concomitant compensatory response by the contralateral unirradiated kidney.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

The analysis of malignant tumours of uncertain origin with immunohistological techniques: clinical follow-up.

In order to assess the clinical value of immunohistological analysis of tumours of uncertain origin, 84 patients have been followed up over a period of up to 9 years. All biopsies had been referred because of diagnostic difficulties. In keeping with previous studies the majority of the cases (69%) were non-Hodgkin's lymphomas, followed by carcinoma (23%) with a mixture of melanomas and sarcomas making up the remaining 8%. The survival of lymphoma cases was clearly better (approximately twice as long) than that of patients with other tumour types. In spite of the difficulties in their histological diagnosis the survival curve for lymphomas, recognised by immunocytochemical means, was very similar to that for the series of high-grade lymphomas reported by the Kiel group. These findings show that lymphomas recognised immunocytochemically behave similarly to other lymphomas and confirm that immunohistological analysis of tumours of uncertain origin is of practical clinical relevance.

Carcinoma↗

Do urine dipsticks reliably predict microhematuria? The bloody truth!

Some literature has cast doubt on the reliability of urine dipsticks in the search for microhematuria. In our study, 2,000 urine dipsticks (two brands) were tested on urine samples containing 0, 0 to 5, 5 to 10, 10 to 20, and 20 to 50 red blood cells per high-power field. The same samples were retested four hours later and the same sticks were tested after four months of aging. Variables controlled for included observer, lighting, performance according to package insert, pH, specific gravity, white blood cells, ascorbic acid, protein, age of dipstick, and exposure of urine to povidine or cleaning solutions. Results obtained using both N-Multistix and Chemstrip 9 urine dipsticks correlated closely with the degree of hematuria. Overall sensitivity was 100%, and specificity was 99.3%. We conclude that these urine dipsticks are reliable and are not affected when tested on urine four hours after void, and that Chemstrips 9 are much more reliable than are N-Multistix if aged in air for four months.

False Negative Reactions↗

Immunity to adult Heligmosomoides polygyrus (Nematospiroides dubius): survival or rejection of adult worms following transplantation to mice refractory to larval challenge.

Experiments were carried out to explore the survival of 14-day adult H. polygyrus following transplantation to mice of four strains, immunized by various protocols. Adult worm establishment and survival was unimpaired in CFLP mice which were totally refractory to larval challenge. Transplanted adult worms were also successful in NIH mice immunized by the 9-day abbreviated infection regime. However, NIH mice exposed to irradiated larvae or subjected to the divided primary infection, expelled transplanted adults. The 9-day abbreviated infection was further examined in SJL and (C57 Bl10 X NIH) F1 mice which expel adult worms during a primary infection and although this regime was unsuccessful in causing NIH mice to reject adult worms, expulsion of adult worms was accelerated in SJL and F1 mice. The survival of adult H. polygyrus was discussed in the context of stage-specific immunity and the delicate balance between the immunogenic stimuli from developing larvae, the immunomodulatory activities of adult stages and the host's genetically determined capacity to respond to these opposing signals.

Animals↗

Suxamethonium dosage in electroconvulsive therapy.

A double-blind study was conducted in 52 patients who received a total of 180 electroconvulsive therapy treatments. Patients were allocated randomly to receive doses of 15 mg, 25 mg or 50 mg of suxamethonium. Those who received suxamethonium 50 mg took significantly longer to breathe again compared with patients who received the lower doses, and were significantly more likely to have a very well modified convulsion than patients who received suxamethonium 15 mg. There were no differences among the groups in the incidences of muscle pains after treatment. We conclude that all three doses were acceptable; however, a dose of 25 mg had practical advantages over 50 mg and theoretical advantages over 15 mg.

Adult↗

Double-blind comparison of a dithranol and steroid mixture with a conventional dithranol regimen for chronic psoriasis.

Twenty four of 30 patients with chronic plaque psoriasis completed a double-blind randomized paired comparison of dithranol in Lassar's paste versus dithranol and fluocinonide in Lassar's paste. There was a more rapid reduction in severity of the psoriasis on the side treated with the dithranol and fluocinonide mixture, but no difference in the final time to clearance between the two sides. There were fewer burning episodes on the side treated with dithranol and fluocinonide and greater staining of the skin. Of the 20 patients who were subsequently followed up for up to 3 months, 11 had relapsed more on the side treated with dithranol and fluocinonide, two on the side treated with dithranol alone and in seven there was no appreciable difference. It was concluded that the addition of a topical steroid to a conventional dithranol regimen produced more rapid initial clearance and less burning, but more rapid relapse of the psoriasis.

Adolescent↗

Renal and related retroperitoneal abscesses: percutaneous drainage.

Renal and related retroperitoneal abscesses cause significant morbidity and mortality and almost always require drainage. The authors report 18 cases of percutaneous drainage of renal and related retroperitoneal abscesses, all of which were successfully managed. In 11 of these cases (61%), percutaneous drainage constituted the only treatment required. In the remaining seven (39%), the patients' clinical status improved after percutaneous drainage, and they were able to undergo subsequent elective nephrectomy with fewer complications. These results are comparable to those achieved with percutaneous abdominal abscess drainage and justify the use of percutaneous drainage for renal and related retroperitoneal abscesses as the therapeutic procedure of choice.

Abscess↗

Effect of verapamil on pulmonary and eicosanoid responses to endotoxin in awake sheep.

Leukotrienes have been suggested to play a role in the endotoxin-induced changes of the pulmonary hemodynamics and airway mechanics. Since Ca2+ is necessary for contraction of airway and vascular smooth muscle as well as for activation of phospholipase A2 and 5-lipoxygenase enzymes, we wondered whether the calcium antagonist verapamil would modify the endotoxin-mediated pulmonary effects as well as the generation of circulating eicosanoids. In twelve conscious sheep, measurements of pulmonary vascular resistance (PVR), systemic vascular resistance (SVR), lung resistance (RL), arterial PO2 (PaO2), leukocyte (WBC) count, arterial thromboxane B2 (TxB2), prostaglandin (PG) F2 alpha, and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) concentrations were obtained before and at predetermined intervals after a 10-min infusion of Escherichia coli endotoxin (0.3 microgram/kg). On separate occasions, the sheep received a bolus injection of verapamil (150 micrograms/kg) before endotoxin, followed by a continuous infusion of verapamil [10 micrograms.kg-1.min-1 (n = 5) or 20 micrograms.kg-1.min-1 (n = 7)] for up to 4 h post-endotoxin. Endotoxin caused a biphasic response with an increase in mean PVR and RL to 326 and 276% of base line during phase I (0-1 h) and lesser increases to 177 and 157% of base line during phase II (1.5-4 h), respectively (P less than 0.05). SVR also showed biphasic increases of 44 and 42% during phase I and II, respectively. Mean PaO2 decreased by 16 Torr and WBC count decreased from 6.4 +/- 1.5 to 3.3 +/- 1.1 thousand/mm3, associated with marked increases in plasma TxB2, PGF2 alpha, and 6-keto-PGF1 alpha.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗

Ethnic variation in estrogen and progesterone receptor concentration in leiomyoma and normal myometrium.

The total content of 17-beta estradiol and progesterone receptors in human uterine leiomyoma and normal myometrium in a Caucasian population was determined. Estrogen receptor concentrations in leiomyoma and myometrium were not significantly different (p = 0.1401). The concentration of progesterone receptors in leiomyoma was higher than in myometrium (p = 0.0303). Negroid and Caucasian ethnic groups did not differ with respect to estrogen (p = 0.7040) or progesterone (p = 0.8494) receptor concentrations in leiomyoma, but estrogen (p less than 0.005) and progesterone (p less than 0.005) receptor concentrations in normal myometrium were significantly higher in Caucasian than in negroid patients. Leiomyoma in negroid and Caucasian patients appears to be histologically similar, but the biochemical pathway of its pathogenesis seems to differ. Genetic predisposition probably acts as an initiation factor in the myometrium of both ethnic groups, then estrogen receptor levels in negroids and alterations in steroid metabolism in Caucasians promote the growth of leiomyoma.

Adult↗