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Biomedical subjects

J Skinner

Publications and source records attributed to J Skinner.

At least 91 records · Page 5Linked to original sources

Monoclonal antibodies against antigens of the human platelet surface: preparation and properties.

Three monoclonal antibodies, FMC24, 25 and 27, reactive with human platelets, are described. In normal blood the 3 antibodies are specific for platelets, but FMC27 reacts with leukemic blast cells in a proportion of acute leukemias. FMC25 precipitates the platelet membrane glycoprotein lb and a glycoprotein of molecular weight 22,000. The antibodies show different effects on platelet aggregation.

Acute Disease↗

The local effects of topically applied estradiol, cyproterone acetate, and ethanol on sebaceous secretion in intact male rats.

Estradiol in ethanol was applied once daily to one flank of intact male rats and sebum production on both flanks was measured over periods of 18 h alternating with 6 h by absorbing the lipid on pads of cigarette paper held in place by a harness, starting on the 15th day. Sebum production was very significantly less on the treated flanks than on the contralateral flanks that received only vehicle, indicating an unequivocal local effect of the estradiol. At the same time, the values on the contralateral flanks were significantly below those of littermate rats which received vehicle only, indicating that the estrogen had been systemically absorbed to produce a distal action. The estradiol also significantly reduced plasma testosterone and the relative weights of the seminal vesicles, ventral prostate, and preputial glands, which demonstrated that part of the general action of the estrogen could have been by suppression of endogenous androgen production. In short-term experiments, in which measurements were started concurrently with treatment, the inhibitory action of estradiol, in contrast to that of cyproterone acetate, was not detected until the 4th day. Indeed, it appeared probable that the estrogen actually stimulated sebum secretion over the first 2 days, suggesting that it had a biphasic effect.

Administration, Topical↗

Fine needle aspiration cytology in the management of lymphoma.

The use of fine needle aspiration (FNA) cytology in the management of patients with lymphadenopathy was investigated. The cases of non-Hodgkin's lymphoma were classified using the Kiel classification, which is based strictly on cytological criteria. Of the 59 cases of biopsy confirmed lymphoma, FNA of nodes showed lymphoma in 53 (90%), no definite diagnosis in five (8%), and false negative diagnosis in one (2%). During the follow-up of patients FNA was positive in seven of the eight cases with a suspected recurrence which was later confirmed by lymph node biopsy. Results suggest that FNA is useful on the initial presentation of a patient with lymphadenopathy. If the diagnosis is unequivocal it helps in planning staging procedures and in selecting involved nodes for biopsy. In some cases with intra-abdominal disease it may obviate laparotomy. However, because false negative diagnoses do occur and because cytological classification of lymphoma is not always accurate FNA should not replace lymph node biopsy at initial presentation, but it can be used as the only investigation to confirm suspected recurrence.

Adolescent↗

The antidiuretic effect of chronic hydrochlorothiazide treatment in rats with diabetes insipidus: water and electrolyte balance.

1. The antidiuretic effect of hydrochlorothiazide in diabetes insipidus was investigated in rats with the hereditary hypothalamic form of the disease (Brattleboro rats). 2. Administration of hydrochlorothiazide in the food resulted in a marked fall in urine volume and a corresponding rise in osmolality. These effects persisted throughout the period of treatment (6-7 days). 3. Body weight and extracellular volume were significantly reduced in the thiazide-treated rats. 4. Hydrochlorothiazide caused an increase in urinary sodium excretion only on the first day of treatment. The resulting small negative sodium balance (in comparison with untreated rats) remained statistically significant for 2 days only. Thiazide-treated rats gradually developed a potassium deficit which was statistically significant from the fourth day of treatment. 5. Total exchangeable sodium, measured after 7 days of thiazide treatment, was not significantly different from that of untreated rats. However, plasma sodium was reduced in thiazide-treated animals, whereas erythrocyte sodium concentration was elevated. 6. It is concluded that the antidiuresis resulting from chronic hydrochlorothiazide administration is associated with a reduction in extracellular volume, but not with a significant overall sodium deficit. Hydrochlorothiazide appears to cause a redistribution of the body's sodium such that the amount of sodium in the extracellular fluid compartment is reduced.

Animals↗

Local suppression of sebum secretion in rats by topical cyproterone acetate in ethanol.

Sebum production was measured on 2 symmetrically placed areas on the flanks of rats over alternating periods of 18 and 6 hr for 4 days, by absorbing the lipid on pads of cigarette paper held in place by a specially designed harness. Castrated rats receiving testosterone produced about twice as much sebum as untreated littermate controls. Once daily application of ethanol to one flank significantly reduced sebum production, in comparison with the other flank in testosterone-treated but not in untreated rats. Daily application of 5 mg cyproterone acetate in ethanol to one flank in a third group of rats significantly reduced sebum production in comparison with that of the other flank treated with vehicle only. The effects became significant within 24 hr. It seems likely that the sebaceous glands received the topically applied materials by way of the pilo-sebaceous orifices rather than by transepidermal absorption. The results demonstrate that one action of cyproterone acetate is at the target site and suggest that the anti-androgen may be effective when applied topically. The method could prove useful in assessing the local action on sebaceous activity of topically applied substances.

Administration, Topical↗

Acute compensatory adaptation of renal function following contralateral kidney exclusion in Brattleboro rats with diabetes insipidus.

1. The function of the remaining kidney following ligation of a single renal pedicle in anaesthetized rats with hereditary hypothalamic diabetes insipidus (DI) was studied using clearance methods. Values were compared with those obtained in DI rats which had been sham operated. 2. A small increase in the glomerular filtration rate of the remaining kidney was observed, which was statistically significant after 150 min. Increases in effective renal plasma flow were also observed, but these were not statistically significant. 3. The fractional excretion rates of Na and K increased immediately after contralateral kidney ligation; as a result total Na and K excretion rates remained similar to values in sham operated animals with both kidneys intact. 4. Fractional urine flow (V/GFR) increased by approximately 40% after contralateral ligation. It is argued that, since water reabsorption in the diluting segments of the nephron was unlikely to have been reduced, the increase in V/GFR was an indication that fractional fluid reabsorption in the proximal nephron had been inhibited. 5. Clearance determinations showed that the fractional reabsorption of Na in the proximal nephron was similarly reduced after contralateral ligation. However, Na reabsorption in the distal nephron increased, though not by enough to prevent a doubling of fractional sodium excretion. 6. The osmolalities of interstitial fluids obtained from the medulla and papilla of the contralateral kidney 2 hr after unilateral renal pedicle ligation were slightly, but significantly, higher than corresponding values in sham operated rats. This raises the possibility that salt reabsorption in the ascending limb of Henle might be enhanced immediately after contralateral renal exclusion.

Adaptation, Physiological↗

Immune-complex mediated colitis in rabbits. An experimental model.

An experimental colitis in rabbits is described, following the intravenous injection of preformed immune complexes of human serum albumin (HSA) and anti-HSA into non-sensitised rabbits. Tissue damage was localised to the colon by the Auer technique of inducing local non-specific inflammation, by the rectal instillation of dilute formalin. Formalin alone gave transient changes that reverted to normal within 24 hours. In rabbits given intravenous immune complexes formed in antigen-excess, a severe colitis was initiated, with histological features including mucosal ulceration, mixed inflammatory cell infiltration in the lamina propria, and crypt abscess formation. It is possible that immune-complex damage may be one of the pathogenic mechanisms involved in human ulcerative colitis.

Animals↗

A systems approach to the child, school, family, and community in an urban area.

Fifteen eighth-grade students, their parents, teachers, and relevant school administrators received a multilevel systems consultation from a community mental health center. Clients were conceptualized and worked with in terms of the subsystem to which they belonged and with regard to the interrelationships of the other subsystems comprising the school-community system. Theoretical considerations following Lewin's life-space concept are described as a basis for this approach in contrast to more traditional ones which typically fail to treat directly, simultaneously, and/or sequentially all client subsystems, e.g., child, school, family, and community. The consultation is described as a case example with each client contributing to the evaluation of the intervention. Although the consultation could not be carried out entirely along the lines originally conceived, it serves as a helpful model for making a more potent impact in school interventions.

Child Behavior Disorders↗

Diphosphonate therapy of paget's disease of bone.

The use of disodium ethane-1 hydroxy-1, 1-diphosphonate (EHDP) therapy for Paget's disease of bone was examined in 75 affected patients. Forty-eight patients received randomly assigned oral doses of either 0, 2.5, 5, 10, or 20 mg/kg/day in a controlled, double-blind protocol, and the remainder received either 10 or 20 mg/kg/day in a non-random protocol. The clinical status of the patients and appropriate laboratory tests were evaluated before treatment and at frequent intervals during a six-month period of initial therapy. There were no significant changes in either urinary hydroxyproline or serum alkaline phosphatase in those patients receiving placebos, while both these parameters decreased significantly at all dose levels of EHDP, with the greatest decline noted in the highest dose group. However, statistical analysis of the data related to changes in symptoms in the double-blind study revealed that patients receiving the higher dose of EHDP (10 or 20 mg/kg/day) had less favorable outcomes than those receiving the lower doses (2.5 or 5 mg/kg/day). The high does group had a relatively lower rate of symptom improvement and a relatively greater rate of deterioration than did the low dose group. Twenty-one of forty-nine patients followed for at least 18 months have shown a sustained suppression of their serum alkaline phosphatase and urinary hydroxyproline values for 12 months following cessation of EHDP, while therapy has been reinstituted for the other 28 patients because of increases in these measurements, with or without accompanying symptomatic deterioration. Eight patients sustained fractures through Pagetic bone during the period of study and all of these were treated with higher doses of EHDP. On the basis of the biochemical and clinical data in this study it appears that initial therapy of Paget's disease of bone with 5 mg EHDP/kg/day maximizes benefits while minimizing possible adverse effects.

Alkaline Phosphatase↗

The removal and restitution of hair fat in the rat.

Castrated male rats were washed with a solution of sodium lauryl sulphate and warm water using a standard technique. Examination of samples of hair clipped from one flank showed that about 50% of the total ether-extractable hair fat was removed. The rate of restitution of hair fat was then measured by clipping a further sample from the opposite flank of each rat after an interval. The plateau level was restored in about 8 days. There was no significant correlation with body weight either of the plateau level in unwashed rats or of the rate of build-up of lipid in washed rats. This result provides no justification for correcting levels of hair lipid for body weight.

Animals↗

The sebotrophic action of growth hormone (BGH) in the rat.

Sebum production of rats was assessed by measuring the levels of fat extractable by diethyl ether from samples of hair clipped immediately after shampooing with sodium lauryl sulphate and 2 days later. By the use of matched litter mates in was unequivocally demonstrated that the response of the sebaceous glands to testosterone is virtually abolished by hypophysectomy and that it can be completely restored by pure bovine growth hormone.

Animals↗