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Biomedical subjects

A Macher

Publications and source records attributed to A Macher.

16 recordsLinked to original sources
PubMed2000

Localization of epithelial sodium channel and aquaporin-2 in rabbit kidney cortex.

The amiloride-sensitive epithelial sodium channel (ENaC) and the vasopressin-dependent water channel aquaporin-2 (AQP2) mediate mineralocorticoid-regulated sodium- and vasopressin-regulated water reabsorption, respectively. Distributions of ENaC and AQP2 have been shown by immunohistochemistry in rats. Functional data from rabbits suggest a different distribution pattern of these channels than in rats. We studied, by immunohistochemistry in the rabbit kidney cortex, the distributions of ENaC and AQP2, in conjunction with marker proteins for distal segments. In rabbit cortex ENaC is restricted to the connecting tubule (CNT) cells and cortical collecting duct (CCD) cells. The intracellular distribution of ENaC shifts from the apical membrane in the most upstream CNT cells to a cytoplasmic location further downstream in the CNT and in the CCD cells. AQP2 is detected in the CCD cells exclusively. The anatomic subdivisions in the rabbit distal nephron coincide exactly with distributions of apical transport systems. The differences between rabbits and rats in the distribution patterns of ENaC and AQP2 may explain functional differences in renal salt and water handling between these species.

Animals↗
PubMed1996

Effect of amlodipine on renin secretion and renin gene expression in rats.

1. This study was done to characterize the influence of calcium channel blockade on renin secretion and renin gene expression in normal rats and rats with renovascular hypertension. To this end we studied the effects of the 1,4-dihydropyridine derivative, amlodipine, on plasma renin activity and renal renin m-RNA levels in normal rats and rats with unilateral renal hypoperfusion induced by applying 0.2 mm left renal artery clips over four days. 2. In normotensive rats, amlodipine significantly decreased basal blood pressure by about 20 mmHg when applied in a concentration of 5, 15 and 45 mg kg-1. Plasma renin activity and also renin mRNA levels were not changed after application of 5 mg kg-1 of amlodipine. However, at a concentration of 15 or 45 mg kg-1, amlodipine, significantly increased not only plasma renin activity by about 250% and 300%, but also renin mRNA levels by about 100% and 500%. The action of amlodipine on all these parameters was maximal after 24 h. Treatment with amlodipine in a concentration of 15 mg kg-1 also increased renin immunoreactive areas in the kidney cortex by retrograde recruitment of renin expressing cells in the afferent arterioles. 3. In 2kidney-1 clip rats, systolic blood pressure rose continuously whilst plasma renin activity and renin m-RNA in the clipped kidney increased transiently and renin m-RNA in the contralateral kidney was constantly suppressed. Amlodipine at a concentration of 15 mg kg-1 markedly attenuated the increase of blood pressure in 2kidney-1 clip rats, produced an almost additive effect on plasma renin activity and showed a tendency to increase renin m-RNA levels in the clipped kidneys. Renin m-RNA levels in the contralateral kidney were also significantly suppressed in the animals receiving additional treatment with amlodipine. 4. These findings suggest that inhibition of calcium channels by amlodipine stimulates renin secretion and renin gene expression in vivo. These stimulatory effects are almost additive to the changes of renin secretion occurring after an unilateral fall of renal perfusion pressure.

Amlodipine↗
PubMed1986

Indications for and diagnostic efficacy of open-lung biopsy in the patient with acquired immunodeficiency syndrome (AIDS).

Pulmonary infiltrates in the patient with acquired immunodeficiency syndrome (AIDS) may be associated with a spectrum of unusual neoplastic and infectious process. Transbronchial biopsy frequently reveals the cause of these infiltrates; however, when transbronchial biopsy is nondiagnostic or contraindicated, or if the patient fails to improve after a diagnostic transbronchial biopsy, further investigation is warranted to direct appropriate therapy. Efficacy of 23 open-lung biopsies in 19 AIDS patients with pulmonary infiltrates was evaluated to define the indications for and the diagnostic yield of open-lung biopsy. Pulmonary infiltrates were recognized for a mean duration (+/- standard error) of 16 +/- 2 days before open-lung biopsy and were associated with fever and cough. These patients did not have prior transbronchial biopsy, and open-lung biopsy was diagnostic in all of these. Prior transbronchial biopsy performed in the remaining 16 patients was nondiagnostic in 10. Open-lung biopsy was diagnostic in 70% of these patients (Pneumocystis carinii pneumonia, 2 patients; Kaposi's sarcoma, 3 patients; Kaposi's sarcoma and Legionella pneumophila, 1 patient; cytomegalovirus, 1 patient). The other 6 patients having a previous diagnostic transbronchial biopsy failed to improve with therapy, and open-lung biopsy resulted in a therapeutic change in 67% of these patients. Two deaths were attributable to open-lung biopsy in patients with postoperative thrombocytopenic hemorrhage. Open-lung biopsy should be performed in AIDS patients when transbronchial biopsy is nondiagnostic or contraindicated, or in patients who fail to improve with appropriate therapy after diagnostic transbronchial biopsy, especially in patients with Kaposi's sarcoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1985

Myelopathy following intrathecal chemotherapy in a patient with extensive Burkitt's lymphoma and altered immune status.

A 30-year-old homosexual man presented with widespread Burkitt's lymphoma. On the basis of immunologic and viral studies, he was suspected of having the acquired immune deficiency syndrome. Following chemotherapy that included intrathecal cytosine arabinoside and methotrexate, brain stem edema, paraplegia, and an elevated cerebrospinal fluid level of myelin basic protein developed. Autopsy revealed vacuolar demyelination of spinal cord, brain stem, and cerebellum. The pathologic findings were similar to those reported to occur in myelopathy associated with intrathecal chemotherapy, but far more extensive. The contribution of the suspected acquired immune deficiency syndrome is unknown.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Prospective randomized study of open lung biopsy versus empirical antibiotic therapy for acute pneumonitis in nonneutropenic cancer patients.

Diffuse pulmonary infiltrates and acute respiratory compromise frequently occur in patients with cancer who are undergoing chemotherapy, and treatment remains controversial. We initiated a prospective randomized trial in 22 nonneutropenic patients to compare the efficacy of immediate open lung biopsy with that of empirical trimethoprim-sulfamethoxazole and erythromycin therapy with delayed open lung biopsy if no clinical improvement occurred after 4 days of therapy. Diagnoses included non-Hodgkin's lymphoma (15 patients), T-cell lymphoma (2), acute lymphoblastic leukemia (3), Hodgkin's disease (1), and breast cancer (1). The median age was 40 years, and fever (18) and tachypnea (13) were the most frequent signs. Median room air arterial oxygen tension in 18 hypoxic patients was 53 mm Hg; 19 patients had diffuse pulmonary infiltrates. Eight of the 10 patients randomized to empirical antibiotic therapy showed improvement after 4 days. The 2 patients whose condition did not improve and who underwent delayed open lung biopsy had Pneumocystis carinii pneumonia. One of them did show improvement, and the other died of respiratory failure. Time to clinical resolution in the 9 surviving patients was 14 days; 4 required prolonged ventilation (longer than 24 hours). Findings for the 12 patients randomized to immediate open lung biopsy were P. carinii pneumonia in 7 and nonspecific pneumonitis in 5; there were 3 deaths related to open lung biopsy. Time to resolution in the surviving patients was 13 days for those with P. carinii pneumonia and 5 days for those with nonspecific pneumonitis; 7 required prolonged ventilation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1985

Disseminated bilateral chorioretinitis due to Histoplasma capsulatum in a patient with the acquired immunodeficiency syndrome.

A 31-year-old white male homosexual was healthy until March 1984, when he developed Pneumocystis carinii pneumonia, which resolved with treatment. In April 1984 he developed fever, followed by hepatosplenomegaly, headaches, blurred vision, pancytopenia and pulmonary infiltrates. On June 11, intracytoplasmic yeast were noted within leukocytes on a peripheral blood smear, and amphotericin B was started. The patient developed progressive respiratory and renal insufficiency and died on June 13, 1984. Autopsy histopathology demonstrated disseminated histoplasmosis and Histoplasma capsulatum was cultured from numerous tissues. Ocular histopathologic examination using special fungal stains and electron microscopy revealed numerous budding yeasts characteristic of Histoplasma capsulatum in the choroid, retina and central retinal vein. Their identification as H. capsulatum was confirmed by immunofluorescent staining.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Educating primary care providers about HIV disease: multidisciplinary interactive mechanisms.

As HIV-related prophylactic and therapeutic research findings continue to evolve, the Health Resources and Services Administration (HRSA) of the Public Health Service has created multidisciplinary mechanisms to disseminate new treatment options and educate primary care providers at rural and urban sites throughout our nation's health care system. HRSA has implemented (a) the International State-of-the-Art HIV Clinical Conference Call Series, (b) the national network of AIDS Education and Training Centers, (c) the nationwide HIV Telephone Consultation Service, and (d) the Clinical Issues Subcommittee of the HRSA AIDS Advisory Committee. These collaborative and comprehensive efforts at HIV information dissemination target physicians, nurses, physician assistants, dentists, clinical pharmacists, mental health care providers, case managers, and allied health professionals. The sites where they provide care include public health clinics; county, State and Federal correctional facilities; private practice offices; community and academic hospitals; military and Veterans Administration facilities; hemophilia centers; schools of medicine, nursing, and dentistry; departments of health; chronic care facilities; visiting nurse and home care agencies; health maintenance organizations; and Indian Health Service clinics and hospitals.

Diffusion of Innovation↗