Monoclonal antibodies OKT 11 and OKT 11A have pan-T reactivity and block sheep erythrocyte “receptors”

Monoclonal antibodies OKT11 (γ1) and OKT11A (γ2) are described and appear to have similar binding specificities. They bind, in immunofluorescence, with >95% of infant thymocytes, staining both cortical and medullary cells, 65-80% of blood lymphocytes and selectively stain the T cell-dependent paracortical areas of tonsil. A small proportion (9-12%) of bone marrow lymphocytes stain, but this population excludes the terminal transferase-positive cells. Both the γ1 and γ2 antibodies stain the surface membrane Ig-negative lymphocytes in blood and tonsil and are able to block sheep E rosette formation (to normal or leukemic T cells). In contrast, other monoclonal anti-T reagents tested (OKT1, OKT3, OKT4, OKT6, OKT8, OKT9, OKT10) did not block E rosette formation. E rosette formation and OKT11 binding are coincident on T-ALL cell lines and both are trypsin-sensitive. In a series of 145 leukemias and 26 leukemic cell lines investigated, only leukemias with a T cell phenotype including E rosette positivity were reactive with OKT11 and OKT11A. OKT11A binds to a polypeptide of approximately 50000 molecular weight on thymic lymphocytes. This structure may carry the recognition site for sheep erythrocytes. These antibodies provide additional useful markers for T cell analysis and are of potential therapeutic value.     

Predominance of capsular polysaccharide type 5 among oxacillin-resistant Staphylococcus aureus.

The relationship between capsular polysaccharide types 5 and 8 and resistance of Staphylococcus aureus to oxacillin was studied with a collection of 406 clinical isolates from six French hospitals. Of 175 type 5 isolates, 84 (48%) were resistant to oxacillin. In contrast, only 8 of 160 type 8 isolates (5%) and 5 of 71 nontypeable isolates (7%) were resistant to oxacillin. Therefore, capsular typing of clinical isolates of S. aureus may facilitate the choice of first-line antibiotic therapy.     

The vigilance-promoting drug modafinil counteracts the reduction of tyrosine hydroxylase immunoreactivity and of dopamine stores in nigrostriatal dopamine neurons in the male rat after a partial transection of the dopamine pathway

We studied the ability of the vigilance-promoting drug modafinil to modulate the anterograde and retrograde changes in tyrosine hydroxylase (TH) immunoreactivity and in dopamine (DA) stores in the nigro-neostriatal DA neurons, following a partial hemitransection of this ascending DA system, using a combined morphometrical, biochemical and behavioural analysis. Modafinil was given daily i.p. in doses of 10–100 mg/kg, starting 15 min after the lesion, and the partially hemitransected rats were killed 2 weeks later. Changes in TH-immunoreactive nerve cell bodies and nerve terminals induced by the partial hemitransection were studied in the substantia nigra and neostriatum in combination with image analysis. The substantia nigra and neostriatum were also subjected to biochemical analysis of DA, 3,4-dihydroxyphenylacetic acid and homovanillic acid levels. Modafinil treatment dose-dependently (10–100 mg/kg) counteracted the hemitransection-induced disappearance of nigral TH-immunoreactive nerve cell body profiles and neostriatal TH-immunoreactive nerve terminal profiles. A 2-week treatment with 100 mg/kg of modafinil also counteracted the hemitransection-induced depletion of DA stores in the neostriatum and the ventral midbrain. Moreover, the repeated daily treatment with modafinil (100 mg/kg) protected against the hemitransection-induced disappearance of striatal 5-hydroxytryptamine, 5-hydroxyindoleacetic acid and noradrenaline levels. Striatal DA function was analysed by studying apomorphine-induced (1 mg/kg, s.c.) ipsilateral rotational behaviour 4 and 11 days after the operation. A marked dose-dependent reduction of ipsilateral rotational behaviour was demonstrated after the daily modafinil treatment in the partially hemitransected rats. In another model involving unilateral nigral microinjections of 6-hydroxydopamine, acute (one single dose) modafinil (100 mg/kg) did not affect the contralateral rotational behaviour induced by apomorphine (0.05 mg/kg s.c.), when given 30 min before the apomorphine. Taken together, morphological, neurochemical and behavioural evidence has been obtained that anterograde and retrograde changes induced in the DA stores and TH immunoreactivity of the nigro-neostriatal DA neurons by a partial hemitransection are counteracted by modafinil in a dose dependent way with 100 mg/kg producing a significant protective action against impairment of DA transmission. The results of this study open up the possibility that modafinil may protect against the anterograde and retrograde degeneration of nigrostriatal DA neurons seen after mechanically induced injury.     

Evaluation of the E test for susceptibility testing of anaerobic bacteria.

The susceptibilities of 105 clinical isolates of anaerobic bacteria were determined by a new method, the E test (AB Biodisk, Solna, Sweden), and were compared with the MICs for these organisms obtained by the reference agar dilution method by using supplemented brucella and Wilkins-Chalgren agars. The E test is a plastic strip with a predefined antibiotic gradient immobilized on one side and a MIC interpretive scale printed on the other side. Strips with cefoxitin, cefotaxime, imipenem, penicillin, metronidazole, and clindamycin were used in this study. A suspension of the test strain equal to the visual turbidity of a no. 0.5 McFarland standard was prepared and swabbed onto a 150-mm-diameter plate. The strips were applied in a radial fashion, and the plates were incubated under anaerobic conditions. After growth had occurred, an ellipse of inhibition was seen around each strip. At the point of intersection of the ellipse with the strip, the MIC was read from the interpretive scale. For most antibiotic-organism combinations, the ellipse was clear and the endpoint was sharp. The E-test MICs were interpreted after overnight and 48-h incubation for 58 of the strains. After overnight incubation, 87% of the E-test MICs were within 1 dilution of the agar dilution MICs, and 98% were within 2 dilutions. After 48 h of incubation, agreement was 86 and 97% respectively. E-test MICs obtained for the Bacteroides fragilis group after overnight incubation were more comparable than those obtained after 48 h of incubation to agar dilution MICs determined at 48 h for all drugs except clindamycin. On brucella agar, there was a 2% categorical discrepancy rate between the E-test MICs and agar dilution MICs, which occurred mostly with cefoxitin. The E test is easy to perform and read, is suitable for all anaerobes, can be used to test single patient isolates as needed, and offers the laboratory a reliable method for susceptibility testing of anaerobic bacteria.     

T lymphocyte subsets in human intestinal mucosa: the distribution and relationship to MHC-derived antigens

T lymphocytes in the normal human intestinal tract have been analysed in tissue sections by a double-marker immunofluorescence technique, combining antiserum to T lymphocyte antigen (HuTLA) with a monoclonal antibody detecting T cells of suppressor-cytotoxic phenotype (OKT8). The distribution of HLA-A -B, -C and Ia-like antigens in intestinal mucosa was also examined by a similar method. In small and large intestine 67 to 90% (mean 70%) of intraepithelial T lymphocytes were of suppressor-cytotoxic phenotype (OKT8+). In contrast, only 27 to 56% (mean 39%) of lamina propria T cells were OKT8+. Intestinal epithelial cells demonstrated strong membrane staining for HLA-A, -B, -C antigens. Ia-like antigens were detected on the epithelial cells of small intestinal villi, but not on colonic epithelial cells. Lamina propria macrophages expressed both HLA-A, -B, -C and Ia-like antigens, the latter having strong membrane and cytoplasmic fluorescence. The distribution of T cells with suppressor-cytotoxic or inducer phenotype in the intestinal epithelium and lamina propria may be related to the differential expression of Ia-like and HLA-A, -B, -C antigens in intestinal mucosa.     

Follow-up of solitary autonomous thyroid nodules treated with 131I

We studied the long-term effects of 131I therapy for solitary autonomous thyroid nodules on the size of the nodule and on thyroid function. Twenty-three patients with autonomous thyroid adenomas that had been treated with 131I from 4 to 16.5 years earlier (mean, 8.5) were examined, and their thyroid function was tested. In 12 patients (54 per cent), the nodules were still palpable, and in 2 they had increased in size. Eight patients (36 per cent) had become hypothyroid. The incidence of hypothyroidism was not related to nodule size or the level of thyroid function before therapy with 131I or to the total dose of 131I that had been given. We conclude that 131I therapy for autonomous thyroid adenoma often causes hypothyroidism and in many cases does not eradicate the offending nodule.     

Effect of "anti-thrombosis" stockings on the venous hemodynamics of the lower extremities. Study using mercury gauge plethysmography

Study by plethysmography with mercury gauge. The authors have analyzed the effects of "anti-thrombosis" stockings on venous hemodynamics of 18 lower extremities, by plethysmography with mercury gauge (Periflow J.S.I.). With this method, they delineate the limits of efficacy of the use of only elastic stockings as prophylactic treatment of the thrombo-embolic disease in immobilized patients.     

Use of a single thyroxine test to evaluate ambulatory medical patients for suspected hypothyroidism

Previous recommendations for the use of thyroid function tests to diagnose patients with possible hypothyroidism have discounted the value of a total thyroxine (T₄) test because many clinically hypothyroid patients have T₄ levels that fall within the “normal” range. The authors examined the predictive value of a total T₄ measurement in the evaluation of ambulatory general medical patients suspected of having hypothyroidism. Pregnant patients and those who were taking medications that interfere with thyroid homeostasis were excluded. Simultaneous T₄ and thyrotropin (TSH) tests of 93 consecutive outpatients suspected to have hypothyroidism but found to be euthyroid and 27 patients discovered to be hypothyroid (TSH>10 μU/ml) were examined. A T₄ of 7.0 μl/dl or less had a sensitivity of 93% with a false-positive rate of 19%. A T₄ greater than 8.0 μg/dl appeared to exclude hypothyroidism (negative posttest probability of 100%). It may be possible to achieve cost savings without loss of diagnostic accuracy by using a single total T₄ measurement for the initial evaluation of suspected hypothyroidism in selected outpatients. Received from the Department of Medicine, General Medicine Unit. University of Rochester School of Medicine and Dentistry, Rochester, New York.     

Advanced Parkinson's disease: use of partial dopamine agonist, ciladopa

Ciladopa is a partial dopamine agonist that is effective in patients with advanced Parkinson's disease who are no longer satisfactorily responding to levodopa. Thirty-one patients participated in a double-blind randomized study of ciladopa (added to levodopa) versus placebo. Among 21 patients randomized to treatment with ciladopa and levodopa, there was a 32% decrease in symptoms on the Modified Columbia University Disability Scale. This change was significant, p less than or equal to 0.05. Eight of the 21 patients (38%) improved by at least 50%. The mean number of hours "on" increased by 20%. This change was significant, p less than or equal to 0.05. Five of the 21 patients (24%) were on for at least 4 hours more than at baseline. Dyskinesias were not increased. The mean dose of ciladopa was 19.5 mg/d. The mean dose of levodopa in Sinemet was decreased by 10%. Studies with ciladopa in humans had to be discontinued because of the occurrence of microscopic testicular tumors in some rodents. Although improvement in patients taking ciladopa was modest, there were few adverse effects. These results are encouraging, because two other partial agonists are now available, and they may be as effective as ciladopa.