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Biomedical subjects

M A Gerber

Publications and source records attributed to M A Gerber.

At least 145 records · Page 8Linked to original sources
PubMed1988

In situ hybridization for cytomegalovirus DNA in AIDS patients.

Infection by cytomegalovirus (CMV) is a frequent cause of morbidity and mortality in patients with acquired immune deficiency syndrome (AIDS). The authors studied the distribution of CMV in 4 patients with AIDS using a commercially available, biotin-labeled CMV DNA probe for in situ hybridization and immunohistochemical staining for the detection of CMV antigen in formalin-fixed paraffin-embedded tissues. The sensitivity and specificity of the hybridization procedure was demonstrated by appropriate controls. The immunohistochemical test for the detection of CMV antigen in routine histologic sections was less sensitive than the in situ hybridization method. CMV DNA was detected not only in cytomegalic inclusion cells, but also in nuclei and cytoplasm of histologically normal-appearing cells such as endothelial cells, pneumocytes, hepatocytes, biliary epithelium, gastrointestinal epithelium, Langerhans islet cells, acinar and duct epithelium of pancreas, adrenal cortical and medullary cells, and prostate epithelium. In addition, CMV DNA, but not CMV antigen, was found in polymorphonuclear leukocytes. These cells may serve as intermediate host or reservoir of CMV and may transmit posttransfusion CMV infection. In situ hybridization on routine histologic sections with a biotinylated CMV DNA probe is a rapid, sensitive, and specific method for diagnostic and experimental pathology.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Morphologic, immunohistochemical, and ultrastructural studies of the production of hepatitis B virus in vitro.

Well differentiated human hepatoblastoma Hep G2 cells after transfection with cloned hepatitis B virus (HBV) genomes produce replicative HBV DNA intermediates, high levels of HBsAg, HBeAg and HBcAg as well as mature Dane particles. To analyze the replication cycle of HBV, we studied the expression of HBV antigens with monoclonal antibodies by immunomorphologic methods in the transfected cells at various time intervals after plating. HBcAg and HBeAg were detected in the cytoplasm and less frequently in the nuclei of transfected cells. The percentage of positive cells increased with time after plating and reached a plateau of about 50% positive cells at 10 days. HBsAg and the large and middle HBsAg polypeptides were observed in the cytoplasm of transfected cells and a maximum of 20 to 30% positive cells was reached during the 3rd week after plating. Examination of viable cells in suspension revealed HBcAg/HBeAg and HBsAg expression on the cell surface. Electron microscopy demonstrated characteristic core particles in the nuclei and cytoplasm and Dane particles in cytoplasmic vesicles and culture media of transfected cells. The HBV producing cells did not show any evidence of a cytopathic effect. These observations demonstrate significant similarities between the HBV DNA transfected cells and infected human hepatocytes which support active HBV replication in vivo. Taken together, the results suggest that the cultured cells may serve as a model to elucidate a number of unsolved problems of the molecular and cellular pathobiology of hepatitis B.

Carcinoma, Hepatocellular↗
PubMed1988

Chronic active hepatitis in a child with human immunodeficiency virus infection.

The pathologic changes in the liver of a child with human immunodeficiency virus infection are described. The liver biopsy specimens show chronic active hepatitis with bile duct damage. To our knowledge, the etiology and pathogenesis of chronic liver disease in children with acquired immunodeficiency syndrome is not known. In this child, chronic active hepatitis is probably related to hepatitis B.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Five vs ten days of penicillin V therapy for streptococcal pharyngitis.

To determine the effectiveness of a short (five-day) course of penicillin V potassium therapy, 172 patients with group A beta-hemolytic streptococcal (GABHS) pharyngitis were randomly assigned to receive 250 mg of penicillin V potassium three times daily for either five or ten days. The patients in the two treatment groups were comparable with respect to clinical findings, compliance, and serologic response to GABHS. A bacteriologic treatment failure was defined as the presence of the same serotype of GABHS in the follow-up as in the initial throat culture and occurred in 13 (18%) of the 73 patients in the five-day treatment group and in six (6%) of the 99 patients in the ten-day treatment group. These findings support the current recommendation for a full ten days of oral penicillin V therapy for the treatment of GABHS pharyngitis.

Child↗
PubMed1987

Role of Chlamydia trachomatis and Mycoplasma pneumoniae in acute pharyngitis in children.

In a group of children with acute, nonstreptococcal pharyngitis, only one (2%) of the 44 children tested showed serologic or direct-immunofluorescence evidence of a recent Chlamydia trachomatis infection. Only two (5%) of the 43 children tested showed serologic evidence of a recent Mycoplasma pneumoniae infection. Neither C. trachomatis nor M. pneumoniae appears to be an important cause of acute pharyngitis in children.

Acute Disease↗
PubMed1987

Cytopathic liver injury in acute delta virus hepatitis.

Hepatitis delta-virus (the delta-agent) is now recognized as a cause of acute hepatitis, fulminant hepatitis, chronic hepatitis, and cirrhosis in hepatitis B surface antigen-positive hosts. This report describes the clinical course and liver biopsy histopathology of acute delta-hepatitis in a young American woman with presumed chronic hepatitis B infection. The liver biopsy specimen features included severe cytotoxic and cytopathic hepatocellular damage, small droplet vacuolar liver cell degeneration, and few parenchymal inflammatory cells, lesions resembling epidemic delta-hepatitis in Venezuelan Indians and experimental chimpanzee delta-superinfection. This case suggests that this form of cytopathic liver injury is an important morphologic expression of delta-virus hepatitis that deserves wider diagnostic recognition.

Acute Disease↗
PubMed1987

Infantile hemangioendothelioma of heterotopic intrathoracic liver associated with diaphragmatic hernia.

An autopsy of a six-hour-old term neonate, who died during surgery for repair of a left diaphragmatic hernia, revealed an infantile hemangioendothelioma type I arising in a heterotopic lobe of liver in the left thorax. The upper pole of the tumor was attached by fibrovascular tissue to the lower lobe of the left hypoplastic lung. A pedicle attached to the lower pole of the heterotopic liver pierced through the diaphragm to the left lobe of the normal liver. This case is an example of an unusual association of congenital malformation and putative neoplasm.

Female↗
PubMed1987

Comparison of cytokeratin expression in primary and metastatic carcinomas. Diagnostic application in surgical pathology.

Metastatic poorly differentiated carcinomas often represent diagnostic difficulties in surgical pathology. Therefore, the expression of cytokeratins of different molecular weights (54, 57, and 66 kd) were compared in paraffin sections of 37 primary carcinomas with their lymph node metastases by an avidin-biotin complex (ABC) method, using monoclonal antibodies. The epithelial tumors consisted of 16 squamous cell carcinomas (SCCs) and 17 adenocarcinomas with different degrees of differentiation (well, moderately, or poorly differentiated), a renal cell carcinoma, a hepatocellular carcinoma, a transitional cell carcinoma of the bladder, and a carcinoid tumor of the stomach. The primary and metastatic tumors showed the same cytokeratin profiles. All SCCs and their metastases were positive for 57-kd cytokeratin and negative for 54-kd cytokeratin. All adenocarcinomas and their metastases were positive for 54-kd cytokeratin and negative for 66-kd cytokeratin. The extent of reactions varied with the differentiation of the carcinomas, with well-differentiated tumors showing more diffuse staining. Cases of lymphoma, sarcoma, and melanoma were negative for the three types of cytokeratins. The results indicate that identification of different molecular weight cytokeratins may be used to distinguish poorly differentiated SCCs from poorly differentiated adenocarcinomas, even in metastatic tumors. In addition, demonstration of these cytokeratins is useful in substantiating presence and identity of small foci of metastases in lymph nodes.

Adenocarcinoma↗
PubMed1987

Immunohistochemical distinction of Paget's disease from Bowen's disease and superficial spreading melanoma with the use of monoclonal cytokeratin antibodies.

The differentiation of Paget's disease from Bowen's disease and Pagetoid superficial spreading melanoma may represent diagnostic difficulties. The special stains used in their differential diagnosis are nonspecific and not always sensitive. Therefore, the expression of cytokeratins of different molecular weights (54, 57, and 66 kilodaltons [kD]) was studied in 26 intraepithelial neoplasms in formalin-fixed paraffin-embedded tissues with the use of an avidin-biotin complex (ABC) method with monoclonal cytokeratin antibodies. These included 9 cases of Paget's disease, 11 cases of Bowen's disease, and 6 cases of Pagetoid superficial spreading melanoma. Paget cells from vulva and breast were always positive for 54-kD cytokeratin, variable for 57-kD cytokeratin, and negative for 66-kD cytokeratin. The neoplastic cells in all 11 cases of Bowen's disease were stained for 57-kD and 66-kD cytokeratins but not for 54-kD cytokeratin. The neoplastic cells in all cases of melanoma did not express any of the cytokeratins studied. The results indicate that antibodies to cytokeratins of different molecular weights may be used as a diagnostic tool in the distinction of Paget's disease from Bowen's disease and melanoma.

Antibodies, Monoclonal↗
PubMed1987

Histology of the liver.

The embryology, gross morphology, and histology of the normal human liver--the single largest organ in the human body--are described. It is emphasized that liver biopsy specimens must be processed with special care in order to obtain optimal sections. Immunohistologic studies of liver tissue have the potential to yield more information than electron microscopy. In surgical and autopsy liver specimens, some histologic alterations may be prominent, but they often have little significance. On the other hand, some morphologic changes, particularly in needle biopsy specimens, are frequently subtle, but may be of diagnostic importance. The pathologist must be familiar with these histologic variations from the normal liver.

Adult↗
PubMed1987

Streptozyme test for antibodies to group A streptococcal antigens.

The ability of the Streptozyme test to identify significant antibody rises in 46 patients with streptococcal pharyngitis was comparable to, but no greater than, that of the antistreptolysin O or antideoxyribonuclease B test and inferior to that of the combined use of both the antistreptolysin O and antideoxyribonuclease B tests. Serum specimens were also simultaneously analyzed with three different lots of Streptozyme reagent. Lot-to-lot variation in the reagent resulted in a significant difference in antibody titer for 18 (19%) of the 92 sera tested. Differences among the three lots also produced variation in determining whether a significant rise in titer had occurred from the acute phase to the convalescent phase serum for a given patient. These observations raise concerns about the standardization of the Streptozyme reagent and document the need for precise identification and quantitation of the streptococcal antigens used in this product.

Antibodies, Bacterial↗
PubMed1987

Major histocompatibility antigen expression in the liver in acquired immunodeficiency syndrome.

Human leukocyte antigen (HLA) class I molecules are normally detected on most nucleated cells, but not on hepatocytes, while the expression of HLA class II antigens is mainly restricted to certain cell types of the immune system. This normal distribution pattern may be altered in human liver in a variety of disorders, particularly in infectious and immune diseases. In view of multiple infections and severe immune alterations in acquired immunodeficiency syndrome (AIDS), we studied the expression of HLA class I and class II antigens in liver obtained at autopsy from ten patients with AIDS and eight control patients, using a panel of monoclonal antibodies and the indirect immunofluorescence method. In spite of viral bacterial, and fungal infections, HLA class I antigens were detected on hepatocytes in only two patients with AIDS. Human leukocyte antigen class II antigens were found unexpectedly on bile duct epithelium in five of ten patients with AIDS and in one of eight control patients. The aberrant HLA class II antigen expression on bile ducts does not appear to be linked to bile duct damage or infection with cytomegalovirus or other agents, but may be related to immune alterations in patients with AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Immunoultrastructural localization of Ia antigens in human endometrium.

The distribution of Ia antigens was studied at the light and ultrastructural levels in 34 proliferative and 16 secretory endometria with two monoclonal antibodies using an avidin-biotin-peroxidase complex method. The endothelial cells, many lymphocytes, and various monocytic-macrophagic cells in the endometrial stroma were Ia positive. Furthermore, Ia antigens were localized to normal endometrial epithelium in the proliferative phase, and focally in epithelium adjacent to stromal lymphoid aggregates throughout the cycle. Expression of Ia antigens in the secretory epithelium was focal or absent. At the ultrastructural level, Ia-positive epithelial cells exhibited staining on the plasma membrane, in free and membrane-bound ribosomes, rough endoplasmic reticulum, and occasional perinuclear cisternae. In the endothelial cells and lymphocytes, Ia antigens were also localized to the plasma membrane and rough endoplasmic reticulum. These findings indicate that endometrial epithelium expresses Ia antigens which may be regulated by endometrial lymphoid cells and/or hormones. The plasma membrane expression of Ia antigens by the epithelial cells of endometrium appears to result from active synthesis, and not merely from passive absorption of Ia antigens.

Adult↗