Biomedical subjects
Publications and source records attributed to H Masur.
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Atovaquone was compared to trimethoprim-sulfamethoxazole (TMP-SMZ) for the relationship of time receiving therapy, plasma drug concentrations, and incidence of adverse reactions in patients with AIDS-associated Pneumocystis carinii pneumonia. Treatment-limiting adverse events occurred in 9% of atovaquone-treated patients and 24% of TMP-SMZ-treated patients. Adverse events usually did not occur before day 7 for either treatment. Only the incidence of rash increased with increasing plasma concentrations of atovaquone. The incidence of anemia, neutropenia, and azotemia increased with increasing trimethoprim plasma concentration, while other adverse events (gastrointestinal disorders, rash, fever, and liver function abnormalities) were independent of plasma drug concentration.
The dimensions of the syrinx, the remaining spinal cord and the degree of cerebellar herniation were analyzed by one- and two-dimensional MRI studies in 22 patients with syringomyelia. A deep and/or broad cyst tends to be a long one. The dimensions of the syrinx and the spinal cord have an inverse relationship. The degree of cerebellar herniation is not related to the longitudinal or transverse extension of the cyst or the ratio cyst/cord or the remaining spinal cord (neither for diameters nor for cross-sectional areas). The dimensions of cysts are not significantly greater in patients with tonsillar herniation than in patients without. We conclude that cerebellar herniation is not a major prognostic factor and should not be overestimated for the development and progression of the disease.
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The mucosa of the gastrointestinal tract is presumably an important reservoir for human immunodeficiency virus type 1 (HIV-1), but the level of virus-expressing cells within the mucosa of infected patients is not known. To study this issue, we identified HIV-1 mRNA-expressing (positive) mononuclear cells by in situ hybridization in specimens of esophageal mucosa from eight patients with acquired immune deficiency syndrome (AIDS) and esophageal infections. Such cells were not found in four patients with AIDS and no esophageal disease. Immunocytochemical staining revealed that the mononuclear cells expressing HIV-1 mRNA were lamina propria macrophages. The prevalence of positive cells was measured by triplicate determinations in each of three experiments using an inverse sampling technique. No significant differences in prevalence were found among patients or among experiments. The overall prevalence of HIV-1 mRNA-expressing cells in the esophageal lamina propria was 0.059 +/- 0.01%. This prevalence of cells expressing HIV-1 mRNA in the mucosa of patients with mucosal infections may reflect the local abundance of stimuli such as bacterial endotoxin and certain cytokines capable of inducing viral transcription.
Secondary infections remain the leading cause of death in patients with the acquired immunodeficiency syndrome (AIDS). Dealing with the rapidly evolving spectrum of infectious problems seen in patients with AIDS requires knowledge of current therapeutic and prophylactic strategies. Through an extensive preclinical trials network supported by both industry and government, an increasing number of new agents are being identified and rapidly moved into clinical trials. Several agents are now available to treat diseases caused by Pneumocystis carinii, and corticosteroids have become a useful adjunct to antimicrobial agents in the treatment of P. carinii pneumonia. Although the treatment of toxoplasmosis remains a challenge, alternatives to sulfadiazine and pyrimethamine are now available. Mycobacterial infections, particularly with Mycobacterium tuberculosis, have become an increasing problem for patients with AIDS, and both old and new combination drug regimens are being used. Cytomegalovirus disease, until recently an untreatable problem, can now at least be partially managed with antiviral agents. The use of more complete prophylactic regimens may decrease the morbidity and mortality from opportunistic infections.
Prevention of opportunistic infections is an integral part of caring for patients infected with human immunodeficiency virus. Mycobacterium avium complex (MAC) bacteremia can cause severe morbidity and excess mortality among these patients. Controlled trials of rifabutin for the prophylaxis of MAC bacteremia have been completed. Rifabutin reduced the incidence of MAC bacteremia by approximately one-half and, when disseminated disease due to MAC (DMAC) did develop, reduced the frequency of associated clinical symptoms. Moreover, prophylaxis with rifabutin was well tolerated. Prophylaxis of MAC bacteremia with macrolide antibiotics is currently being investigated, but no data from large-scale prospective trials are yet available. On the basis of trials completed thus far, the U.S. Public Health Service has recently recommended the use of rifabutin (300 mg/d) as prophylaxis for MAC bacteremia in patients with fewer than 100 CD4+ lymphocytes/mm3. The widespread use of this prophylactic regimen could reduce the rates of morbidity and mortality caused by DMAC. However, rifabutin must be administered only after careful consideration of the circumstances of individual patients. Potential drug interactions, cost, and compliance are important factors in the decision about which patients should receive prophylaxis.
Dihydropteroate synthase is the target enzyme for the sulfonamide compounds, which are the mainstay of therapy for Pneumocystis carinii pneumonia, a common infection in patients with impaired immunity. The stability of this enzyme, its kinetic constants with respect to substrates, and the 50% inhibitory concentration (IC50) of several sulfonamides and the sulfone dapsone have been characterized using both cell-free and intact organism assay systems. Stability of the enzyme is dependent on storage temperature, reducing reagents, and to a lesser extent, protease inhibitors. The sulfonamides sulfadiazine and sulfamethoxazole were found to be highly potent inhibitors of P. carinii dihydropteroate synthase with IC50s of 0.42 and 0.71 microM, respectively. Dapsone had equivalent potency when compared with the most potent sulfonamides tested in both assay systems. Data suggest that sulfamethoxazole, sulfadiazine and dapsone may represent equivalent choices as P. carinii dihydropteroate synthase inhibitors, assuming an equivalent in vivo drug exposure can be achieved.
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OBJECTIVES: To investigate the effects of Pneumocystis carinii on the cardiovascular system. To compare the hemodynamic data from patients with P. carinii pneumonia with those data from patients with bacterial pneumonia with sepsis. DESIGN: Retrospective, descriptive study of prospectively gathered hemodynamic and clinical data. SETTING: Tertiary referral hospital, medical intensive care unit. PATIENTS: Forty-one consecutive patients with severe P. carinii pneumonia and 31 patients with bacterial pneumonia who had invasive hemodynamic monitoring for management of hypotension and/or hypoxemia. MEASUREMENTS AND MAIN RESULTS: On initial presentation, both groups had a hyperdynamic hemodynamic profile that included tachycardia, an increased cardiac index, and a low systemic vascular resistance index. The mean heart rate of the P. carinii pneumonia patients (113 +/- 3 beats/min) was significantly lower than that of the patients with bacterial pneumonia (126 +/- 4 beats/min). The cardiac index, systemic vascular resistance index, pulmonary vascular resistance index, and pulmonary artery pressures did not differ significantly between the two groups. The patients with bacterial pneumonia had a significantly lower mean left ventricular stroke volume index and stroke work index than the patients with P. carinii pneumonia. CONCLUSION: P. carinii can produce a hyperdynamic hemodynamic profile similar to that seen in patients with bacterial pneumonia with sepsis.
OBJECTIVE: This study reports the clinical and radiologic findings in seven patients infected with HIV who had 10 consecutive episodes of symptomatic cholecystopathy induced by infusion of interleukin-2. SUBJECTS AND METHODS: Ten episodes of right upper quadrant pain associated with gallbladder wall thickening were seen in seven of 29 HIV-infected patients who received IV interleukin-2. Patients received 6-18 million IU/day of continuous interleukin-2 infusion for 5 days. Patients with right upper quadrant pain underwent sonographic examinations, which were interpreted prospectively. Medical records and previous sonographic studies were reviewed retrospectively. Follow-up was obtained through outpatient visits and sonography. RESULTS: Right upper quadrant pain during these 10 episodes of cholecystopathy usually developed 4-5 days after starting infusion of interleukin-2. Sonography during that time showed gallbladder wall thickening (mean thickness, 12.4 mm; range, 5-18 mm) and a wide variety of sonographic appearances. Tenderness during sonography was focal in six episodes, diffuse in one, and absent in three. Sludge was identified in one episode; calculi were not seen. Findings on radionuclide biliary scans were normal in three cases. Symptoms abated rapidly in every case after infusion of interleukin-2 was reduced or stopped. No surgery was necessary. When treatment was repeated, three patients had recurrent episodes, with clinical courses and sonographic aberrations showing little variance from the initial episodes. Follow-up sonography in three episodes showed a maximal thickness of the gallbladder wall of 4 mm. No patient had a history or laboratory evidence of intrinsic biliary disease. CONCLUSION: Symptomatic thickening of the gallbladder wall during infusion of interleukin-2 can exactly mimic other forms of acalculous cholecystitis, except that when associated with interleukin-2 the thickening is rapidly reversible and surgery is not required. Radionuclide scans can be useful in clinical decision making. The process appears to be benign, and cessation of interleukin-2 therapy, along with close clinical observation, appears to be the appropriate treatment.
The aim of this SPECT study was to determine whether there is a correlation between rCBF (99mTc-HMPAO) and D2 receptor binding (123I-IBZM) in disorders of the extrapyramidal system and in which situation the 99mTc-HMPAO scan could predict the outcome of the 123I-IBZM study. 13 patients with Parkinson's syndrome and 13 patients with hyperkinetic extrapyramidal disorders were studied. In all patients the two SPECT studies were performed within 2-7 days. ROIs were placed over the basal ganglia (BG), the frontal cortex (FC) and the cerebellum (CE). The ratios BG/FC and BG/CE were calculated. In both groups the scatter was lower when the frontal cortex was used as reference region. Among the patients with hyperkinetic extrapyramidal disorders the two patients with Huntington's chorea had lower rCBF and D2 receptor binding compared to other hyperkinetic extrapyramidal disorders. There was no correlation between D2 receptor binding and rCBF in the basal ganglia. The 99mTc-HMPAO studies did not provide clinically useful information, except in Huntington's chorea.
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