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Biomedical subjects

S Davies

Publications and source records attributed to S Davies.

At least 19 recordsLinked to original sources

Phenelzine vs atenolol in social phobia. A placebo-controlled comparison.

Seventy-four patients who met DSM-III criteria for social phobia completed 8 weeks of double-blind, randomly assigned treatment with the monoamine oxidase inhibitor phenelzine sulfate, the cardioselective beta-adrenergic blocker atenolol, or placebo. The overall response rates were 64% for phenelzine, 30% for atenolol, and 23% for placebo. Phenelzine was widely superior to both atenolol and placebo on independent rater analyses and, to a lesser extent, on self-report, with no significant differences between atenolol and placebo. At the end of 16 weeks, phenelzine was still significantly superior to placebo, while atenolol showed an intermediate response that did not differ significantly from either of the other treatments. Patients with generalized social phobia constituted 76% of the sample, and they were preferentially responsive to phenelzine. The small size of the discrete social phobic sample precluded separate outcome analyses for this subtype. Overall, the findings support the responsivity of social phobia to monoamine oxidase inhibitors.

Adolescent

Stress test reactivity in panic disorder.

The psychological and physiological reactivity of 52 patients with panic disorder to mental arithmetic, cold pressor, and 5% carbon dioxide inhalation tests was compared with that of 26 age- and sex-matched normal subjects. In general, patients with panic disorder were neither more physiologically reactive to these stressors than normal subjects nor slower to recover from them, but they were tonically more anxious and much more likely to ask to stop carbon dioxide inhalation or to report panic attacks during this test. Patients who reported panic attacks (46%) had manifested greater anticipatory anxiety before the gas was delivered, accompanied with increased beta-adrenergic cardiac tone. Thus, anticipatory anxiety can be an important factor in panic provocation. Physiological measures varied greatly in their sensitivity to phasic or tonic anxiety. Carbon dioxide stimulated large increases in respiratory minute volume, but these increases were no greater for patients than for normal subjects.

Adult

Pulmonary aspergillosis: an unusual cytologic presentation.

Cytologic identification of Aspergillus is usually based on recognition of hyphal elements; conidia are rarely seen. We report a case of autopsy-proven pulmonary Aspergillosis which was studied antemortem by bronchoalveolar lavage. This mass arose in the clinical setting of chronic necrotizing pulmonary aspergillosis. The specimen contained numerous conidia, some of which exhibited germination. No hyphae were seen. This unusual cytologic expression of clinically significant fungal disease could be easily overlooked. Distinction of Aspergillus conidia from contaminating pollen is discussed.

Aspergillosis

Infra red coagulation for bleeding mucosal telangiectasia.

The technique of infra red coagulation is well suited to the destruction of superficial blood vessels in the skin and/or mucosal surfaces. A method is described here for the destruction of resistant bleeding telangiectasia of the palate and lip in Osler-Weber-Rendu syndrome.

Diathermy

A comparison of the chemical repair rates of free radical precursors of DNA damage and cell killing in Chinese hamster V79 cells.

One of the important temporal stages of radiation action in cellular systems is the chemical phase, where oxygen fixation reactions compete with chemical repair reactions involving reducing agents such as GSH. Using the gas explosion technique it is possible to follow the kinetics of these fast (greater than 1 ms) reactions in intact cells. We have compared the chemical repair kinetics of the oxygen-dependent free radical precursors leading to DNA single-strand and double-strand breaks, measured using filter elution techniques, with those leading to cell killing in V79 cells. The chemical repair rates for DNA dsb (670s-1 at pH 7.2 and 380s-1 at pH 9.6) and cell killing (530s-1) were similar. This is in agreement with the important role of DNA dsb in radiation induced cell lethality. The rate for DNA ssb precursors was significantly slower (210s-1). The difference in rate between DNA ssb and dsb precursors may be explained on the basis of a dsb free radical precursor consisting of a paired radical, one radical on each strand. The instantaneous probability of one or other of these radicals being chemically repaired and not proceeding to form a dsb will be twice that of ssb radical precursor. This agrees well with the concept of locally multiply damaged sites (LMDS) produced from clusters of ionizations in DNA (Ward 1985).

Animals

The role of non-protein sulphydryls in determining the chemical repair rates of free radical precursors of DNA damage and cell killing in Chinese hamster V79 cells.

Chinese hamster V79 fibroblasts were irradiated in the gas explosion apparatus and the chemical repair rates of the oxygen-dependent free radical precursors of DNA double-strand breaks (dsb) and lethal lesions measured using filter elution (pH 9.6) and a clonogenic assay. Depletion of cellular GSH levels, from 4.16 fmol/cell to 0.05 fmol/cell, by treatment with buthionine sulphoximine (50 mumol dm-3; 18 h), led to sensitization as regards DNA dsb induction and cell killing. This was evident at all time settings but was particularly pronounced when the oxygen shot was given 1 ms after the irradiation pulse. A detailed analysis of the chemical repair kinetics showed that depletion of GSH led to a reduction in the first-order rate constant for dsb precursors from 385 s-1 to 144 s-1, and for lethal lesion precursors from 533 s-1 to 165 s-1. This is generally consistent with the role of GSH in the repair-fixation model of radiation damage at the critical DNA lesions. However, the reduction in chemical repair rate was not proportional to the severe thiol depletion (down to approximately 1% for GSH) and a residual repair capacity remained (approximately 30%). This was found not to be due to compartmentalization of residual GSH in the nucleus, as the repair rate for dsb precursors in isolated nuclei, washed virtually free of GSH, was identical to that found in GSH-depleted cells (144 s-1), also the OER remained substantially above unity. This suggests that other reducing agents may have a role to play in the chemical repair of oxygen-dependent damage. One possible candidate is the significant level of protein sulphydryls present in isolated nuclei.

Animals

Eflornithine versus cotrimoxazole in the treatment of Pneumocystis carinii pneumonia in AIDS patients.

OBJECTIVES: To compare cotrimoxazole and eflornithine as primary treatment for first-episode Pneumocystis carinii pneumonia (PCP). DESIGN: Prospective open-labelled study. METHODS: Patients were randomized to eflornithine (400 mg/kg daily, as a continuous intravenous infusion) or cotrimoxazole (3.84 g twice daily, intravenously) for 14 days. RESULTS: Only 39% of patients treated with eflornithine (20 out of 51) and 40% of those given cotrimoxazole (nine out of 47) successfully completed therapy. Although 12 out of the 36 patients with confirmed PCP were treated successfully with eflornithine, significantly more patients were withdrawn from the eflornithine group because of therapy failure (25 out of 51 versus 10 out of 47, P = 0.007). This significant difference persisted in patients in whom a diagnosis of PCP was confirmed histologically (19 out of 33 versus seven out of 27, P = 0.03). Significantly more patients were withdrawn from cotrimoxazole because of serious drug-related side-effects (38 versus 12%, P = 0.005). CONCLUSIONS: Eflornithine (400 mg/kg daily) is less effective than cotrimoxazole (7.68 g daily) as treatment for first-episode PCP. Eflornithine does have activity against P. carinii in humans.

AIDS-Related Opportunistic Infections

Diagnosis of Pneumocystis carinii pneumonia in HIV antibody positive patients by simple outpatient assessments.

BACKGROUND: As increasing numbers of patients with immunosuppression induced by the human immunodeficiency virus (HIV) present with respiratory symptoms it is important to differentiate Pneumocystis carinii pneumonia from other chest diseases rapidly and start treatment early. The management of pneumocystis pneumonia could be improved if clinicians could diagnose this condition confidently on the basis of simple clinical assessments. METHODS: Three hundred and eighteen patients with evidence of immunosuppression due to HIV infection and suspected pneumocystis pneumonia were investigated. A clinical history was taken and arterial blood gas analysis, chest radiography, oximetry during exercise, and sputum induction or bronchoscopy (or both) were performed. RESULTS: Pneumocystis pneumonia was confirmed microscopically from induced sputum or bronchoalveolar lavage fluid in 154 patients; 118 had other chest disease. The remaining 46 patients had no definitive diagnosis. The best single independent predictors of a diagnosis of pneumocystis pneumonia were exercise induced oxygen desaturation and obvious interstitial infiltrates on the chest radiograph (odds ratios of 4.88 and 5.44 respectively). The symptom triad of exertional dyspnoea, cough, and fevers; the absence of pneumocystis pneumonia prophylaxis; and resting arterial hypoxaemia were less predictive (odds ratio 2.07, 3.72, and 0.69). An algorithm was developed that gave a positive predictive value for confirmed pneumocystis pneumonia of 95% and also identified those patients with a very small chance of having pneumocystis pneumonia (negative predictive value 85%). CONCLUSIONS: The diagnosis of an initial episode of pneumocystis pneumonia can be confidently made in a large proportion of immunosuppressed patients with respiratory symptoms on the basis of clinical symptoms, the absence of prophylaxis, chest radiographic appearances, and oxygen desaturation during exercise as shown by oximetry. Using these simple features clinicians can rapidly assign patients to the appropriate type of management at presentation.

Ambulatory Care

Open trial of intravenous clomipramine in five treatment-refractory patients with obsessive-compulsive disorder.

In a preliminary trial, five oral-clomipramine-refractory patients with obsessive-compulsive disorder (OCD) were treated openly with 14 intravenous clomipramine infusions each. Using standardized assessments, three patients were rated as much improved, one as unchanged, and one as minimally improved. Statistically significant improvements were noted on both the Yale-Brown Obsessive Compulsive Scale and the NIMH Global OCD scores. No patient discontinued treatment because of side effects. Although the results are provocative in that three of five patients were much improved at the end of the protocol, conclusions about preferential efficacy for the intravenous route must await a placebo-controlled trial.

Administration, Oral

Immunoreactive beta-core-like material in normal postmenopausal urine: human chorionic gonadotrophin or LH origin? Evidence for the existence of LH core.

Material with the immunochemical properties of the beta-core of human chorionic gonadotrophin (hCG) can be found in the urine of normal postmenopausal women. However, we have been unable to detect intact hCG (using an assay which is specific for the alpha-beta heterodimer of intact hCG) in serum of such subjects. The levels of serum LH and urinary beta-core were compared in matched samples from 28 women (serum LH: median 27 U/l, range 4-70 U/l, urinary beta-core: median 0.27 microgram/l, range less than 0.05-0.645 microgram/l). Urine (4 litres) from three postmenopausal women was concentrated, dialysed and subjected to gel exclusion chromatography on Sephadex G-100. Fractions were analysed by specific assays for LH, intact hCG, total beta-hCG (free beta-subunit and intact hCG), free alpha-subunit and beta-core. Material eluting at the expected position of the beta-core fragment of hCG was detected in all three samples by the beta-core, beta-hCG and LH assays, despite the fact that the LH antibody does not recognize the authentic beta-core of pregnancy. Electrophoresis and Western blotting of the concentrated urines revealed that material of the same molecular size as beta-core was recognized by the antibody to LH but not by a monoclonal antibody raised to free beta-hCG which also recognizes the beta-core molecule of hCG. We conclude that the predominant core-like material identified in postmenopausal urine is probably derived from the beta-subunit of LH.

Aged

Glomerular injury induced by hydrogen peroxide: modifying influence of ACE inhibitors.

The sensitivity of isolated glomeruli from normotensive (Wistar-Kyoto, WKY) and spontaneously hypertensive (SHR) strains to oxidant stress was studied by determining the incidence of pyknosis, karyohexis and karyolysis after incubation with different concentrations of hydrogen peroxide (H2O2) (4.7 x 10(-9) - 10(-3) M). Even though the proportion of glomeruli containing nuclei that demonstrated these features increased progressively with increasing concentrations of H2O2, the number of severely damaged glomeruli was relatively small even at concentrations of 4.7 x 10(-3) M. Examination of the surface epithelial cells of glomeruli using scanning electron microscopy revealed no evidence of disturbance of the macroscopic or podocyte structure or, of increased blebbing after H2O2-treatment. These data suggest damage to nuclei is an early result of ROS stress on glomeruli. Preincubation of WKY glomeruli with captopril or lisinopril resulted in a significant drop in the proportion of WKY glomeruli demonstrating structural damage after oxidant stress. In contrast, preincubation of SHR glomeruli with lisinopril had no effect on oxidant-induced changes in the morphology of SHR glomeruli, whereas captopril effected a significant increase in the proportion of glomeruli demonstrating damage at all concentration of H2O2.

Angiotensin-Converting Enzyme Inhibitors

Failure of simple biochemical indexes to reliably differentiate fulminant Wilson's disease from other causes of fulminant liver failure.

Serum, urine and tissue biochemical findings were studied in 21 cases of fulminant Wilson's disease with respect to the value of a recently described biochemical index based on serum alkaline phosphatase and total serum bilirubin levels, and these cases were compared with 193 other cases of fulminant liver failure. Serum bilirubin, alkaline phosphatase and AST levels found in fulminant Wilson's disease were significantly different from those found in other cases of fulminant liver failure, but differentiation from other causes of fulminant liver failure on the basis of these biochemical parameters was not possible. The alkaline phosphatase/bilirubin and aspartate AST/bilirubin ratios derived from the above parameters were also significantly lower in fulminant Wilson's disease than in other categories of fulminant liver failure, but distinction between diagnostic categories on this basis was not possible. When ratios that correctly identified all cases of fulminant Wilson's disease were selected, 59/190 (31%) and 84/190 (44%) cases of non-Wilsonian fulminant liver failure would erroneously be assigned a diagnosis of fulminant Wilson's disease, by alkaline phosphatase/bilirubin and AST/bilirubin ratios, respectively. A low alkaline phosphatase-to-bilirubin ratio (< 0.57) in any category of fulminant liver failure suggested a significantly worse prognosis than in cases with higher ratios (chi 2, Yates' corrected = 5.37, p = 0.02). In the Wilson's disease group, serum and hepatic copper and ceruloplasmin concentrations were normal in 4/21, 2/15 and 2/19, respectively, whereas urinary copper level was elevated in 18/18 and was the most valuable test in diagnosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Successful treatment of bone marrow failure in Gaucher's disease with low-dose modified glucocerebrosidase.

We report the beneficial effects of enzyme replacement therapy with mannose-terminated human glucocerebrosidase ('Ceredase') in a patient suffering from transfusion-dependent bone marrow failure due to Gaucher's disease. Treatment with low-dose enzyme infusions, given twice weekly, rapidly reversed the haematopoietic failure and incapacitating skeletal disease. It appears likely that prior splenectomy favourably influenced the response to this therapy.

Bone Marrow Diseases

Pharmacokinetics of R 82913 in patients with AIDS or AIDS-related complex.

R 82913, a tetrahydroimidazobenzodiazepinthione (TIBO) derivative with potent activity against human immunodeficiency virus 1 (HIV-1) in vitro, was given to 22 patients with AIDS or AIDS-related complex in a dose-escalating pilot study. Doses of 10 to 300 mg administered daily by intravenous infusion were well tolerated for up to 50 weeks, with no haematological or biochemical evidence of toxicity. Mean OKT4 cell count rose slightly during the second month of treatment when higher steady-state plasma concentrations of the drug were achieved. Median p24 antigen concentration fell by 41% during the first month of therapy. When the rise in p24 antigen before therapy was compared to the fall during treatment, end-point analysis showed a significant difference (p less than 0.03). The combination of potent antiretroviral activity in vitro and the observed effect on HIV p24 antigen and absence of toxicity in vivo indicate that R 82913 and related TIBO derivatives merit further study in the treatment of retroviral infections.

AIDS-Related Complex