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Biomedical subjects

M de Medina

Publications and source records attributed to M de Medina.

28 records · Page 2Linked to original sources
PubMed1991

Immunophenotyping of lymphocytes in liver tissue of patients with chronic liver diseases by flow cytometry.

Immunological factors are important in the pathogenesis of a spectrum of hepatobiliary diseases. To characterize the nature of specific immunological responses in liver disease, we determined lymphocyte changes in liver tissue and in blood using flow cytometry. A total of 113 liver biopsy specimens was collected from patients with the following diseases: 19 chronic hepatitis B; 39 chronic non-A, non-B hepatitis; 27 alcoholic liver disease; 10 hepatic malignancy; 8 autoimmune hepatitis; 6 fatty liver and 4 primary biliary cirrhosis. The lymphocytes were isolated from the liver biopsy specimens by mechanical and enzymatic methods. The lymphocyte yield was 7,901 +/- 575 cells/mg of liver tissue. The viability of lymphocytes was 97.7% +/- 0.3%. Lymphocytes were stained with four pairs of two-color mixed fluorescein-conjugated monoclonal antibodies, including T4-T8 (CD4/CD8), T11-B1 (CD2-CD20), NKH1-T8 (CD56-CD8), IL-2R1-T11 (CD25-CD2), and the ratios were determined by an Epics Profile flow cytometer. Immunophenotyping of lymphocytes in whole blood samples was simultaneously analyzed. Variability in lymphocyte yield and different patterns of lymphocyte subsets were found in the liver biopsy specimens. The yields of lymphocytes from patients with chronic non-A, non-B and autoimmune hepatitis were highest, and the lowest yield was from patients with fatty liver. Patients with primary biliary cirrhosis, fatty liver and hepatic malignancy had relatively high ratios of CD4/CD8, CD56/CD8 and CD25/CD2; whereas patients with chronic hepatitis B, autoimmune hepatitis and non-A, non-B hepatitis had lower ratios of CD4/CD8, CD56/CD8 and CD25/CD2. No difference in lymphocyte ratios between the patients with cirrhotic and noncirrhotic alcoholic liver disease was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Separation↗
PubMed1990

HIV-1 and HTLV-I infection in renal transplant recipients.

The prevalence of retroviral infection in renal transplantation remains poorly defined. We tested retrospectively sera from 224 of 331 patients undergoing renal transplantation between 1979 and 1985. Viral antigen based EIA was used for screening IgG antibodies to human immunodeficiency virus (HIV-I) and human T-cell leukemia virus type I (HTLV-I). Positive EIAs were confirmed by Western blot. Six patients (2.7%) were found to have retroviral infection, four with HIV-1 and two with HTLV-I. The four patients with HIV-1 infection were negative before and became EIA and Western blot positive following transplantation. All patients had transient HIV-1 antigenemia documented before antibody was detected. One patient died of Kaposi's sarcoma 2 years posttransplantion with a functioning graft. One is alive and asymptomatic 4 years posttransplant, and two rejected their grafts and are asymptomatic on maintenance hemodialysis. Six patients tested positive for HTLV-I by EIA. Only two patients, however, were also positive for HTLV-I by Western blot, RIPA, and p24 antigen RIA, one prior to and one after transplantation. Both had HTLV-I-positive lymphocyte cultures and remain asymptomatic of retroviral infection 3 years after renal transplantation. A third patient, positive for HTLV-I by EIA, had indeterminate Western blot and negative RIPA, RIA, and lymphocyte culture. Intravenous drug use was not a risk factor for retroviral infection in this patient population. It is likely that patients became infected peritransplantation from blood transfusions. Contamination by donor kidneys, however, cannot be excluded.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Human immunodeficiency virus and human T-cell leukemia virus type I in patients undergoing maintenance hemodialysis in Miami.

The high prevalence of human immunodeficiency virus (HIV-1) infection in populations at risk in Miami prompted a seroepidemiologic study of both HIV-1 and the human T-cell leukemia virus type I (HTLV-I), a closely related virus, in our patients receiving chronic hemodialysis. One hundred twenty-nine patients undergoing hemodialysis in 1986 and 1987 were tested for antibody against both viral antigens by EIA (Abbott Laboratories, Abbott Park, IL). Seroreactive samples for HIV-1 and/or HTLV-I were confirmed by Western blot and, for HTLV-I, by viral cultures. Thirty patients (23.2%) were positive for retroviral infection (22 for HIV-1 alone, four for HTLV-I alone, and four for both HIV-1 and HTLV-I). The most important risk factor was intravenous drug use, followed by blood transfusion. Patients with HIV-1 had lower T4-T8 ratios and higher mortality than those with HTLV-I infection alone. It was concluded that HTLV-I, as well as HIV-1, infection is endemic in chronic dialysis centers in Miami. The clinical consequences of HTLV-I infection in relatively immunocompromised patients with chronic uremia who are undergoing chronic hemodialysis remains to be established.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Failure of Centers for Disease Control criteria to identify hepatitis B infection in a large municipal obstetrical population.

The Centers for Disease Control (CDC) has recommended screening pregnant women from high-risk populations for hepatitis B surface antigen (HBsAg). To assess the adequacy of the risk criteria, all women presenting for delivery to a large municipal hospital were screened. Sera from 5356 women were tested, and questionnaires designed to identify women at high risk were completed by 78% of these patients. Sixty-four women were found to be HBsAg seropositive (1.2%). If the CDC criteria had been applied for screening, 30 of the seropositive mothers (47%) would not have been identified. Women from some Latin American and Caribbean countries not recommended for screening were found to have a relatively high prevalence of hepatitis B infection. Reluctance to give a history of venereal disease or illicit drug use may be another factor in the failure of the CDC screening strategy. To achieve effective immunoprophylaxis of newborns, all pregnant women should be screened for HBsAg carriage.

Carrier State↗
PubMed1986

Elevated levels of immunoglobulins and immune complexes in the bile of patients with primary sclerosing cholangitis.

The concentration of immunoglobulins and immune complexes was determined in the serum and bile of four patients with primary sclerosing cholangitis, only one of whom had chronic ulcerative colitis, and in four postcholecystectomy control patients. The result of the immunoglobulin studies demonstrated increased serum levels of IgM in primary sclerosing cholangitis as compared to control patients. The IgG, IgA, and IgM in bile were all significantly elevated as compared to controls (p = 0.02). Immune complexes in bile and serum were also determined in both groups by the C1q and conglutinin binding assays. Immune complexes in bile were elevated in three of four of the patients with primary sclerosing cholangitis. These findings further characterize primary sclerosing cholangitis in terms of biliary immunoglobulins and immune complexes but do not resolve whether these changes are an epiphenomenon or reflect a primary role of immunoglobulins and immune complexes in the pathogenesis of this disorder.

Adult↗
PubMed1982

An institutional outbreak of hepatitis B related to a human biting carrier.

An outbreak of hepatitis B in a residential institution for the mentally retarded was studied. Initially one overt case of hepatitis was noted. A serologic screen of students and employees revealed a total of 12 individuals positive for hepatitis B surface antigen (HBsAg). Subtyping by radioimmunoassay subsequently demonstrated that the population of HBsAg-positive individuals could be subdivided into two groups, based on the HBsAg subtype: adw2 or ayw3. The five individuals with subtype adw2 all were carriers. The ayw3 group, in contrast, were acutely infected except for one carrier with persistent hepatitis B e antigen. Both the ayw3 carrier and several of the acutely infected individuals were aggressive biters. Human biting, a frequent occurrence in the classroom studied, was one probable mode of transmission in this outbreak. The resolution of the outbreak was achieved by rapid screening for HBsAg with subtyping of positive patients and careful observation of the setting for putative modes of transmission.

Adolescent↗
PubMedDate not supplied

Factors that influence serum hyaluronan levels in hemodialysis patients.

Serum hyaluronan levels are increased in dialysis patients. We evaluated several factors that influence serum hyaluronan levels in 184 patients on chronic hemodialysis (duration 2.3 +/- 2.3 [SD] years). The levels were higher than normal in the whole group and in a subgroup of 133 patients without chronic infection, liver disease, or rheumatoid arthritis (215 +/- 19 and 205 +/- 22 microg/L, respectively). There was a tendency for the levels to be higher in a subgroup of patients with hepatitis c virus (HCV) infection. There was no correlation between hyaluronan levels, alanine aminotransferase (ALT), and duration or dose of dialysis. A weak but highly significant negative correlation between serum albumin levels and serum hyaluronan and ferritin levels was seen. The data suggest that chronic inflammation may explain, at least in part, the increased hyaluronan levels found in chronic dialysis patients.

Adult↗
PubMedDate not supplied

Quantitative detection of hepatitis C virus RNA in patients undergoing hemodialysis.

The purpose of the current study was to detect quantitatively hepatitis C virus (HCV)-RNA among patients undergoing maintenance hemodialysis. Study subjects were 88 patients on hemodialysis at the Miami Veterans Administration Medical Center and the REN Dialysis Unit at the University of Miami School of Medicine. There were 66 men and 22 women, mean age 52 years (range, 22-87 years), and mean duration of dialysis was 2.8 years (range 0.2-12.5 years). Seventy-three percent had a history of blood transfusion. Anti-HCV was determined by enzyme linked immunosorbent assay (ELISA), confirmed by four antigen strip immunoblot assay (RIBA 2.0 SIA). HCV-RNA was quantitated directly in human sera using a branched DNA (bDNA) signal amplification assay. Twenty-seven of 88 (31%) patient samples were found to be anti-HCV reactive by ELISA. Twenty-two of 27 were confirmed reactive, 2 were indeterminate, and 3 were nonreactive by RIBA HCV. Eighteen of 22 (82%) reactive by RIBA 2.0 HVC were found to have detectable (> 3.5 X 10(5) Eq/ml) HCV-RNA levels (mean [&/- SD], 43.3 +/- 35.4 X 10(5) Eq/ml; range 4.9-123.3). No additional cases were identified with reverse transcription polymerase chain reaction (RT-PCR) using 5' untranslated region "nested" primers. HCV-RNA was not detected in four RIBA HCV 2.0 reactive, the two intermediate, or the 64 patient samples nonreactive for anti-HCV. The two epitopes most commonly associated with HCV-RNA were c22-3 and c33c. Sixteen of 18 (89%) patients with detectable levels of HCV-RNA had normal alanine aminotransferase (ALT). Three patients with the highest levels of HCV-RNA were infected with the human immunodeficiency virus. The authors conclude that HCV-RNA by bDNA assay is a sensitive, specific, and simple test that can be used in association with antibody assays and a PCR-based assay to study the prevalence and management of HCV infection in the dialysis setting.

Adult↗