Search PubMed⌕ Search

Biomedical subjects

M A Gerber

Publications and source records attributed to M A Gerber.

270 records · Page 15Linked to original sources
PubMed1971

New patterns of immunoglobulin deposition in the lesions of malignant nephrosclerosis, with special reference to IgE.

Localization of immunoglobulins (including IgE), complement and fibrinogen and the morphologic alterations in the kidneys of 10 patients with malignant nephrosclerosis were investigated. Thirteen kidneys with benign nephrosclerosis and 5 normal ones were also studied. In contrast to a previous series of patients with malignant nephrosclerosis, the number of necrotic arterioles and the deposition of IgG and complement in the renal arterioles, were reduced in a parallel fashion. These differences seem to reflect modern treatment and support the hypothesis that IgG and complement play a role in the pathogenesis of the arteriolar necrosis in the disease. IgE was deposited massively in many renal arterioles of 9 patients with malignant nephrosclerosis. The role of reaginic antibody in the pathogenesis of the disease is not clear since IgE was also focally present in some arterioles of 4 normal kidneys and of 8 kidneys with benign nephrosclerosis.

Adolescent↗
PubMedDate not supplied

Presence of receptors for polymerized albumin in HBsAg-containing hepatocytes and hepatoma cell line.

Recent evidence suggests that hepatitis B virions (HBV) and HBsAg particles contain receptors for polymerized human serum albumin (pHSA). We studied, by immunohistochemical techniques, the relationship between HBsAg and pHSA receptors in liver tissue from eight patients with chronic HBV infection and in a human hepatocellular carcinoma cell line (PLC/PRF/5) producing HBsAg. Both parallel sections and double fluorescent antibody staining of liver tissue demonstrated that only HBsAg-containing hepatocytes expressed pHSA receptors. The receptors could not be demonstrated in eight HBsAg negative livers. Sequential studies of PLC/PRF/5 cells revealed that pHSA and HBsAg emerged simultaneously in the cytoplasm, on the cell surface, and in the supernatant culture media. These findings indicate that pHSA receptors are closely associated with HBsAg during its synthesis and secretion by hepatocytes and suggest that the receptors are HBV-specific.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Histologic studies of severe delta agent infection in Venezuelan Indians.

To supplement a detailed epidemiologic study of an outbreak of viral hepatitis in Venezuelan Indians in isolated valleys, apparently resulting from delta agent infection, 10 autopsy specimens were studied histologically and immunocytochemically, and five biopsy specimens were examined. The patients were children and young adults and predominantly males. A sequence of hepatitis from focal necrosis with conspicuous small-droplet steatosis, through massive necrosis, prolonged postnecrotic collapse to early cirrhosis with massive collapse was postulated. The histologic changes tentatively suggest a cytopathic effect of the delta agent without significant indication of lymphocytotoxicity, at least in the parenchyma. Delta agent was demonstrated in hepatocyte nuclei in moderate amounts in the focal-necrotic stage and in isolated cells in the massive-necrotic stage, but in large amounts during the transition to cirrhosis. Whether these patients, in whom neither HBcAg nor HBsAg were demonstrable in the liver, suffered exclusively from superinfection of hepatitis B virus carriers and/or coinfection of hepatitis B virus with the delta agent remains to be resolved. Delta infection may occur in isolated settings with no relation to Italian origin, drug addiction, or polytransfusion. The infection is far more widely spread than previously assumed.

Adolescent↗
PubMedDate not supplied

Ultrastructural studies of fibroblasts transfected with hepatitis B virus DNA.

Cultured 3T3 mouse fibroblasts transfected with cloned hepatitis B virus genome and DNA coding for methotrexate-resistant dihydrofolate reductase, produce and secrete significant amounts of hepatitis B surface antigen (HBsAg). Ultrastructural morphometry revealed that fibroblasts transfected with hepatitis B virus DNA contained significantly more lysosomes than did fibroblasts transfected with the gene coding for methotrexate resistance or normal fibroblasts. Although abundant HBsAg was found in the cytoplasm of transfected fibroblasts by immunologic methods, HBsAg particles were not detected by electron microscopy. Immunoelectron microscopy localized HBsAg to the nuclear envelope, rough endoplasmic reticulum, and endoplasmic cisternae. These findings suggest that the transfected cells produce mainly nonparticulate HBsAg or that they have a defect in intracisternal packaging of HBsAg into particles.

Animals↗
PubMedDate not supplied

Specific histologic features of Santa Marta hepatitis: a severe form of hepatitis delta-virus infection in northern South America.

Stimulated by observations in an outbreak of hepatitis delta-virus infection among Yucpa Indians in Venezuela, in which unusual histologic features were found, we studied 100 cases of fatal hepatitis from Colombia, South America, which had been obtained by autopsy or viscerotomy. These cases were considered to be "Santa Marta hepatitis," or "hepatitis of the Sierra Nevada de Santa Marta," which has been observed in this region for more than 40 years. Of the 100 cases, 19 had a variety of histologic lesions or were normal, and hepatitis delta-virus antigen was not demonstrated immunocytochemically in any of them. By contrast, 81 cases had a characteristic histologic picture with intense microvesicular steatosis associated with conspicuous eosinophilic necrosis of the hepatocytes, which apparently were sluggishly removed by cytolysis. Hepatitis delta-virus antigen was detected in 70% of the 81 cases, and the absence of detection of this antigen was often associated with poor tissue preservation and more extensive hepatocyte necrosis. A smaller percentage of patients had hepatitis B virus antigens detectable in liver tissue. The characteristic lesion in these 81 cases could be distinguished from other causes of microvesicular steatosis by the extensive eosinophilic necrosis. Other variable accompanying features included intraacinar, mainly macrophagic, scavenger cell inflammation, intense portal inflammation, a parenchymal regeneration, and ductular and arteriolar proliferation. Santa Marta hepatitis as a severe form of hepatitis delta-virus infection differs markedly from fulminant delta-hepatitis in Europe and the United States in which the microsteatosis with marked eosinophilic degeneration is not found. The causes for these differences are unknown but may relate to nutritional factors or environmental toxins.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Viral↗
PubMedDate not supplied

Epidemiologic aspects of Santa Marta hepatitis over a 40-year period.

"Santa Marta" hepatitis has been recognized as an unusual type of severe hepatitis occurring in northern Colombia since 1930. Liver specimens from a historic viscerotomy series, used by Gast-Galvis to identify cases and describe epidemiologic features of this disease, were available for review and histopathologic staining for delta-virus. Of 86 liver specimens examined from cases of fulminant Santa Marta hepatitis, 81 showed a distinct histopathologic picture, in various stages of progression, with features of eosinophilic necrosis, microvesicular fat infiltration of the liver parenchyma and morula cells; 69% were positive for delta-antigen by immunoperoxidase staining. This disease occurred predominantly in several small towns within 50 km of Santa Marta, with mortality reaching 1.25 per 1,000 inhabitants per year during the 1940's. Children under age 15 were most commonly affected and males affected twice as frequently as females. Liver specimens obtained from children, or within 15 hr of death, or which showed early histologic stages of disease were most likely to be positive for delta-antigen. This and the accompanying study confirm the existence of a distinct type of fulminant hepatitis in Colombia for over 50 years. The epidemiologic and histopathologic features are comparable to severe hepatitis in Venezuela Indians and in the Amazon basin of Brazil, suggesting that all are caused by delta-superinfection of hepatitis B virus carriers.

Adolescent↗
PubMedDate not supplied

Demonstration of pre-S polypeptides of hepatitis B virus in infected livers.

The large (pre-S1), middle (pre-S2) and major (P24) polypeptides of HBsAg have been defined in detail, but their role in hepatitis B virus infection is not known. Therefore, we studied the expression of pre-S1, pre-S2 and P24 in the liver of 15 patients with acute or chronic hepatitis B virus infection using monoclonal and polyclonal antibodies in a double staining immunofluorescence method. The pre-S and major HBsAg polypeptides were co-expressed in the hepatocyte cytoplasm of all patients except for one case of chronic active hepatitis and cirrhosis. HBcAg was present in hepatocyte nuclei of nine patients suggestive of active hepatitis B virus replication. These studies support the hypothesis that the pre-S polypeptides represent essential components of the envelope of hepatitis B virus.

Adolescent↗
PubMedDate not supplied

Management of streptococcal pharyngitis reconsidered.

Adequate treatment of GABHS pharyngitis with penicillin shortens the course of illness, reduces the spread of streptococci and prevents suppurative complications. It has also been a major factor in the markedly accelerated decline in the incidence of acute rheumatic fever in this country. Difficulties in the clinical diagnosis of GABHS pharyngitis make bacteriologic confirmation highly desirable. Currently a properly performed throat culture is the best way to obtain this bacteriologic confirmation. However, it is possible that rapid antigen detection tests will replace the throat culture in the future. These diagnostic tools should be used more selectively and only in conjunction with clinical and epidemiologic data. Greater selectivity will help control costs and will increase the chances of identifying patients who are truly infected and are not merely streptococcal carriers. Penicillin is still the drug of choice and an oral preparation given twice daily is as effective as more frequent doses. Patients at risk for noncompliance should be treated with a single injection of benzathine penicillin combined with procaine penicillin to lessen the local discomfort. Routine follow-up cultures of asymptomatic patients should be abandoned. Persistence of GABHS following a course of treatment may no longer be an important risk factor for the development of rheumatic fever. However, there are exceptional cases, as noted in the text, in which eradication of GABHS carriage with a short course of rifampicin may be desirable.

Administration, Oral↗
PubMedDate not supplied

The Tulane University Medical Center/Columbia partnership: opportunities and challenges for pathology.

A joint venture between the largest health-care corporation in the country (Columbia/HCA) and Tulane University Hospital/Clinic was established about 1 year ago. Early indications are that the partnership is successful and mutually beneficial. For Tulane University Medical Center, the joint venture provides financial stability and support for academic centers of excellence. Tulane University Hospital/Clinic will become the referral center for complicated cases from the regional Columbia hospitals. The Tulane University Hospital laboratories are positioned to become the regional referral laboratory for esoteric testing. For the pathologists of the regional Columbia hospitals, the opportunity beckons to form a group of equal partners that will contract with Columbia to provide laboratory services at Columbia hospitals and to consolidate the laboratories in the New Orleans division. Columbia has brought corporate expertise, capital, and opportunities for cost-saving economies of scale to the partnership. Quality and cost-effectiveness of patients care will be emphasized as will research on clinical outcomes. This model of corporate/academic partnership represents a new option for academic medical centers around the country as they respond to the rapid changes in the health-care environment.

Academic Medical Centers↗
PubMedDate not supplied

Intracranial inflammatory pseudotumor.

An intracranial mass thought clinically and by computed tomography and angiography to be a meningioma proved to be an inflammatory pseudotumor. The lesion was composed of sheets of mature plasma cells and lymphocytes with germinal center formation. Immunohistochemical studies revealed a polyclonal cell population, supporting a diagnosis of a reactive lesion rather than a plasma cell neoplasm. Inflammatory pseudotumor should be considered in the differential diagnosis of a sharply demarcated intracranial mass clinically and radiologically diagnosed as meningioma.

Aged↗