Biomedical subjects

G W Rankin

Publications and source records attributed to G W Rankin.

6 recordsLinked to original sources

PubMed2000

Characterization of two divergent lineages of macaque rhadinoviruses related to Kaposi's sarcoma-associated herpesvirus.

We have cloned and characterized the entire DNA polymerase gene and flanking regions from Kaposi's sarcoma-associated herpesvirus (KSHV) and two closely related macaque homologs of KSHV, retroperitoneal fibromatosis-associated herpesvirus-Macaca nemestrina (RFHVMn) and -Macaca mulatta (RFHVMm). We have also identified and partially characterized the corresponding genomic region of another KSHV-like herpesvirus, provisionally named "M. nemestrina rhadinovirus type 2 (MneRV-2)," with close similarity to rhesus rhadinovirus (RRV). A sequence comparison of these four macaque viruses and two KSHV-like gammaherpesviruses recently identified in African green monkeys, Chlorocebus rhadinovirus types 1 and 2 (ChRV-1 and ChRV-2) reveals the presence of two distinct lineages of KSHV-like rhadinoviruses in Old World primates. The first rhadinovirus lineage consists of KSHV and its closely related homologs RFHVMn, RFHVMm, and ChRV-1, while the second more distantly related lineage consists of RRV, MneRV-2, and ChRV-2. Our findings raise the possibility of the existence of another human KSHV-like herpesvirus belonging to the second rhadinovirus lineage.

Amino Acid Sequence↗

PubMed1997

Absence of detectable human herpesvirus 8 in the semen of human immunodeficiency virus-infected men without Kaposi's sarcoma.

The prevalence of human herpesvirus 8 (HHV-8)/Kaposi's sarcoma (KS)-associated herpesvirus was investigated in the semen of 99 human immunodeficiency virus (HIV)-infected men (median CD4 cell count, 357/mm3) by use of a polymerase chain reaction (PCR) assay capable of detecting <10 copies of HHV-8 DNA. Of the subjects, 95 (96%) self-identified as men who have sex with men (MSM), and 3 had a history of clinical KS. Seminal cell specimens were negative for HHV-8 in 98 subjects. None of the 26 without KS (27.1% of 96 tested) who were seropositive for HHV-8 by IFA for latency-associated nuclear antigens had HHV-8 detected in their semen. The only subject with any evidence for seminal HHV-8 DNA was seropositive for HHV-8 and had active KS. HHV-8 was detected in 10 (10.4%) of 96 peripheral blood mononuclear cell specimens. The prevalence of HHV-8 DNA by PCR in semen of HIV-infected MSM without KS is low.

AIDS-Related Opportunistic Infections↗

PubMed1997

Identification of two homologs of the Kaposi's sarcoma-associated herpesvirus (human herpesvirus 8) in retroperitoneal fibromatosis of different macaque species.

Simian retroperitoneal fibromatosis (RF) is a vascular fibroproliferative neoplasm which has many morphological and histological similarities to human Kaposi's sarcoma (KS). Like epidemic KS in AIDS patients, RF is highly associated with an immunodeficiency syndrome (simian acquired immunodeficiency syndrome [SAIDS]) caused by a retrovirus infection. Recently, a new gammaherpesvirus, called Kaposi's sarcoma-associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8), has been identified in KS tumors, suggesting that KS has a viral etiology. Our previous experimental transmission studies and epidemiological data suggest that RF also has an infectious etiology. In order to determine whether a similar virus is also associated with RF, we have assayed for the presence of an unknown herpesvirus using degenerate PCR primers targeting the highly conserved DNA polymerase genes of the herpesvirus family. Here we provide DNA sequence evidence for two new herpesviruses closely related to KSHV from RF tissues of two macaque species, Macaca nemestrina and Macaca mulatta. Our data suggest that KSHV and the putative macaque herpesviruses define a new group within the subfamily Gammaherpesvirinae whose members are implicated in the pathogenesis of KS and KS-like neoplasms in different primate species.

Amino Acid Sequence↗

PubMed1993

A new microcellular cytotoxicity test based on calcein AM release.

We present a microtest for cell-mediated immunity, based on the use of the Tarasaki tray and calcein AM vital dye. The number of target cells needed has been reduced to 500 per test with a corresponding tenfold reduction in the number of effector cells needed. Results were read at the rate of 1 second per test using a fluorimeter attached to a microscope. Each reaction was also confirmed visually with the use of ethidium bromide as a counterstain for dead cells. The calcein AM dye used to stain the living cells was shown to have a low spontaneous leakage rate--less than 15% in 4 hours at 37 degrees C. Dilutions of targets stained by calcein AM had a linear relationship with measured fluorescence values. NK cells, LAKs, and CTLs were readily detectable by this microtest. Quantitation of killing and kinetic analysis was readily performed with this test system. A significant positive correlation to 51Cr-release results was found. We conclude that the microtest should find wide application in studies of cell-mediated immunity.

Cell Line↗

PubMed1990

Sensitization to kidney transplants.

1. Greater than 50% PRA-sensitized first kidney graft recipients show significantly lower graft survival rates than nonsensitized (0-10% PRA) and moderately sensitized (11-50% PRA) recipients. Most of the effect of sensitization can be seen within the first month posttransplantation. 2. Increases in cellular immunity or antibodies not currently detected by lymphocyte cytotoxicity may account for the decreased graft survival rates in second and multiple graft recipients. One possibility involves the presence of antiplatelet antibodies. 3. Transfusions seem to be the weakest stimulus for sensitization when compared to pregnancy, and to graft failure, which is the strongest. In addition, low numbers of transfusions tend to have a beneficial effect, especially on second kidney graft survival. 4. During the years since the prospective use of the T-cell FCXM by Los Angeles transplant centers, there has been a marked increase in graft survival rates for multiple graft recipients. However, the rates for the sensitized multiple transplant group still remain lower than those for the nonsensitized first and multiple graft groups.

Cadaver↗

PubMedDate not supplied

Comparison of velocity-encoded MR imaging and fluid dynamic modeling of steady and disturbed flow.

The contrast of flow-encoded magnetic resonance (MR) images obtained in vivo and the accuracy of velocity measurements are complicated by the presence of complex flow states. The effects of complex flow states on MR flow-encoded images were studied and quantitative flow information was obtained with an MR phase-subtraction technique. Regions of complex flow, including flow stagnation and separation and laminar flow, could be clearly identified on the phase images. The MR imaging velocity measurements were validated by comparison with numerical simulation results for three-dimensional velocity distributions. The velocity MR images and the profiles obtained from the simulation generally agreed well for flow rates of 660 and 1,680 mL/min. This agreement lends support to both the fluid dynamic model and the physical basis of the phase imaging technique and establishes the validity of flow-encoded phase imaging as an in vivo flow quantitation method, especially under low Reynolds number flow conditions.

Blood Flow Velocity↗