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Biomedical subjects

W Hardy

Publications and source records attributed to W Hardy.

18 recordsLinked to original sources
PubMed2001

Baboon mesenchymal stem cells can be genetically modified to secrete human erythropoietin in vivo.

Human mesenchymal stem cells (MSCs) are capable of differentiating into multiple mesenchymal lineages including chondrocytes, osteocytes, adipocytes, and marrow stromal cells. Using a nonhuman primate model, we evaluated nonhuman primate MSCs as targets for gene therapy. Baboon MSCs (bMSCs) cultured from bone marrow aspirates appeared as a homogeneous population of spindle-shaped cells. bMSCs were capable of differentiating into adipocytes and osteocytes in vitro and chondrocytes in vivo. bMSCs were genetically modified with a bicistronic vector encoding the human erythropoietin (hEPO) gene and the green fluorescent protein (GFP) gene. Transduction efficiencies ranged from 72 to 99% after incubation of MSCs with retroviral supernatant. Transduced cells produced from 1.83 x 10(5) to 7.12 x 10(5) mIU of hEPO per 10(6) cells per 24 hr in vitro before implantation. To determine the capacity of bMSCs to express hEPO in vivo, transduced bMSCs were injected intramuscularly in NOD/SCID mice. In a separate experiment, transduced bMSCs were loaded into immunoisolatory devices (IIDs) and surgically implanted into either autologous or allogeneic baboon recipients. Human EPO was detected in the serum of NOD/SCID mice for up to 28 days and in the serum of five baboons for between 9 and 137 days. NOD/SCID mice experienced sharp rises in hematocrit after intramuscular injection of hEPO-transduced bMSCs. The baboon that expressed hEPO for 137 days experienced a statistically significant (p < 0.04) rise in its hematocrit. These data demonstrate that nonhuman primate MSCs can be engineered to deliver a secreted and biologically active gene product. Therefore, human MSCs may be an effective target for future human gene therapy trials.

Adult↗
PubMed2001

Mesenchymal stem cells are capable of homing to the bone marrow of non-human primates following systemic infusion.

OBJECTIVE: The human bone marrow contains mesenchymal stem cells capable of differentiating along multiple mesenchymal cell lineages. Using a non-human primate model, we sought to determine whether the systemic infusion of baboon-derived mesenchymal stem cells was associated with toxicity and whether these cells were capable of homing to and persisting within the bone marrow. MATERIALS AND METHODS: Five baboons (Papio anubis) were administered lethal irradiation followed by intravenous autologous hematopoietic progenitor cells combined with either autologous (n = 3) or allogeneic (n = 2) mesenchymal stem cells that had been expanded in culture. In four of these baboons, the mesenchymal stem cells were genetically modified with a retroviral vector encoding either the enhanced green fluorescent protein gene (n = 3) or the human placental alkaline phosphatase gene (n = 1) for tracking purposes. A sixth animal received only intravenous gene marked autologous mesenchymal stem cells but no hematopoietic stem cells or conditioning irradiation. RESULTS: Following culture, baboon mesenchymal stem cells appeared morphologically as a homogeneous population of spindle-shaped cells that were identified by the monoclonal antibodies SH-3 and SH-4. These cells did not express the hematopoietic markers CD34 or CD45. Baboon mesenchymal stem cells isolated from primary culture were capable of differentiating along both adipogenic and osteogenic lineages. There was no acute or chronic toxicity associated with the intravenous infusion of mesenchymal stem cells. In all five recipients of gene marked mesenchymal stem cells, transgene was detected in post-transplant bone marrow biopsies. In two animals receiving autologous mesenchymal stem cells, including the one non-conditioned recipient, transgene could be detected over 1 year following infusion. In one recipient of allogeneic gene marked mesenchymal stem cells, transgene was detected in the bone marrow at 76 days following infusion. CONCLUSION: These data demonstrate that baboon mesenchymal stem cells: 1) are not associated with significant toxicity when administered intravenously, 2) are capable of homing to the bone marrow following intravenous infusion, and 3) have the capacity to establish residence within the bone marrow for an extended duration following systemic administration.

Alkaline Phosphatase↗
PubMed1996

Mutual confounding and interactive effects between hepatitis C and hepatitis B viral infections in hepatocellular carcinogenesis: a population-based case-control study in Taiwan.

A population-based case-control study was conducted in Taiwan to determine the hepatitis C virus (HCV)-associated risk of hepatocellular carcinoma (HCC) in a hyperendemic area for hepatitis B virus (HBV) infection. A total of 58 recently diagnosed HCC patients and 225 matched community controls, who participated in a community-based liver cancer screening program, were recruited between March 1991 and March 1994. Control subjects were matched to HCC patients by age (+/- 5 years), sex, residence, and date of serum sample collection (+/- 3 months). Serum samples from all study subjects were tested for hepatitis B surface antigen (HBsAg) and antibodies to HCV (anti-HCVs) by enzyme immunoassays, as well as HCV RNA by reverse transcription-PCR assays. Accordingly, patients with HCC were more likely than were controls to be positive for HBsAg (82.8% versus 12.9%, with an odds ratio (OR) of 22.9), anti-HCVs (13.8% versus 4.4%, with an OR of 3.9), and HCV RNA (13.8% versus 5.8%, with an OR of 2.7). After adjustment for anti-HCVs and HCV RNA positivities, the matched ORs associated with HBsAg increased to 27.6 and 28.1, respectively, whereas the corresponding adjusted ORs for anti-HCVs and HCV RNA after controlling for HBsAg status were increased to 8.8 and 6.2, respectively. In the meantime, interactive effects between HCV and HBV on risk were also observed. Compared with those who were negative for both anti-HCVs and HBsAg, the matched ORs associated with the sole positivity of anti-HCVs and HBsAg were 4.0 (95% confidence interval = 0.7-24.0) and 24.6 (95% confidence interval = 9.5-64.1), respectively, whereas 6 HCC cases but none of control subjects were positive for both anti-HCVs and HBsAg. These results indicate that there are mutual confounding and interactive effects between HCV and HBV with respect to their links to HCC in this endemic area of chronic HBV infections.

Adult↗
PubMed1989

AIDS-related vacuolar myelopathy is not associated with coinfection by human T-lymphotropic virus type I.

Assessment of antibodies against human T-lymphotropic virus type I (HTLV-I) by enzyme-linked immunoassay, immunofluorescence, and Western blot was undertaken in patients with pathologically or clinically diagnosed acquired immunodeficiency syndrome-related vacuolar myelopathy to determine whether this retrovirus could be etiologically implicated in this disorder. No serological evidence for HTLV-I was found in the patients with vacuolar myelopathy, though 1 patient with an atypical myelopathy did have antibodies against HTLV-I.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Performance of serological assays for early detection of human immunodeficiency virus type 1 seroconversion.

Early detection of sexually transmitted human immunodeficiency virus type 1 (HIV-1) infection was investigated in newly infected persons to determine the sensitivities of currently available serologic techniques. Serial serum samples were obtained from 51 newly infected persons in a cohort of 1,153 homosexual or bisexual men participating in the Baltimore Center of the Multi-Center AIDS Cohort Study during the first 2.5 years of follow-up. Of 51 participants, 45 seroconverted between any two seminannual visits and 6 were found to have been infected just prior to study entry. Five enzyme-linked immunosorbent assays (ELISAs), two immunoblots, and an HIV-1 P24 antigen capture assay were performed on a panel of all serial serum samples from these individuals. The sensitivity of ELISAs varied between 50 and 84% in seroconverters with less-developed antibody response. In this group of seroconverters, the most sensitive antibody assay was an immunoblot from Biotech (95%) and HIV-1 P24 was found infrequently (9.5%). The sensitivities of ELISAs and immunoblot were 100% in individuals with more-developed antibody patterns, and no HIV-1 P24 was detected among them.

AIDS Serodiagnosis↗
PubMed1982

Adenosine receptor-mediated accumulation of adenosine 3',5'-monophosphate in guinea pig thyroid tissue.

The cAMP content of guinea pig thyroid fragments was increased 2- to 3-fold by adenosine analogs, 5'-N-ethylcarboxamide adenosine (NECA), the most potent, caused half-maximal stimulation of 0.7 microM, whereas N6-phenylisopropyl adenosine was much less potent (half-maximal stimulation at 20 microM). Exogenous adenosine by itself was slightly active, and its activity was increased in the presence of adenosine deaminase or transport inhibitors. Although adenosine analogs are partial agonists compared to TSH or the diterpene cyclase activator forskolin, the fractional rate of cAMP accumulation is greater for NECA than for TSH. The stimulatory effect of NECA was antagonized by theophylline. These effects of adenosine and its analogs on cAMP formation in intact thyroid tissue are characteristic of stimulatory adenosine receptors.

Adenosine↗
PubMed1982

Digital image processing: a path to better pictures.

Digital image processing has been used for over a decade to provide startling improvements in the quality of photographs from deep space, satellites and low light level photography. In the last decade considerable work has gone on in major microscope labs in applying these techniques to electron micrographs. Within the last few years a number of factors have come together which allow large scale image processing techniques to be applied at reasonable costs in microscope labs everywhere. The system described here provides hardware for digitization and storage of multiple images simultaneously and multimode scan generation. System software provides easy scan control, image digitization, automatic prescale adjust on acquisition, grey scale histogram generation, grey scale manipulation, image filtering, smoothing, and random color assignment to grey levels.

Animals↗
PubMed1975

Chromatographic separation and antigenic analysis of proteins of the oncornaviruses. V. Identification of a new murine viral protein, p15(E).

Profiling of murine leukemia virus (MuLV) proteins by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate (SDS-PAGE) has revealed a low-molecular-weight protein which does not appear in the corresponding region of viral protein profiles obtained by gel filtration in 6 M guanidine hydrochloride. This protein species, termed p15(E), is easily demonstrable in MuLV isolates for which the viral p15 and p12 proteins have almost identical electrophoretic mobilities; this leaves a protein slightly larger than these two in the PAGE system unaccounted for in the gel filtration system. However, antiserum against the void volume fraction of the gel filtration eluate precipitated the p15(E) component from solubilized, radiolabeled virions, as shown by SDS-PAGE analysis of such immunoprecipitates. Comparative radioprecipitation analyses of this type revealed that for various MuLV isolates p15(E) was distinguishable from p15 in terms of serological reactivities, relative mobilities in gel electrophoresis, and relative efficiencies of labeling with individual amino acids. Thus it appears that, as is the case for avian oncornaviruses, MuLVs contain seven major structural proteins.

Animals↗
PubMed1971

Inactivation of influenza and other viruses by a mixture of virucidal compounds.

A mixture of benzalkonium chloride, Triton X100, and citric acid (Resiguard F) had a marked virucidal effect on lipid-containing deoxyribonucleic and ribonucleic acid viruses, such as vaccinia virus, herpesvirus, and influenza virus. Adenoviruses and picornaviruses were more resistant to inactivation. Electron microscopy showed that influenza particles became aggregated in the presence of Resiguard F and that the outer fringe of hemagglutinin and neuraminidase spikes seen in control virus preparations became indistinct. The mixture had no detectable antiviral activity in mice infected with influenza AO/PR/8/34 virus, and this was attributed to the reduced virucidal effect of Resiguard F in the presence of serum proteins.

Adenoviridae↗