Biomedical subjects

M McCarthy

Publications and source records attributed to M McCarthy.

At least 235 records · Page 13Linked to original sources

PubMed1996

Infection of primary human fetal astrocytes by human herpesvirus 6.

Human herpesvirus 6 (HHV-6) is a lymphotropic betaherpesvirus which productively infects human CD4+ T cells and monocytes. HHV-6 is the etiologic agent for exanthem subitum (roseola), and it is well-known that central nervous system complications occur frequently during the course of HHV-6-associated disease. In addition, HHV-6 has been associated with encephalitis or encephalopathy. However, very little is known about its tropism for neural cells. There are reports that HHV-6 may infect some glial cell lines, but whether it can infect any primary neural cells is not known. Our studies show that both HHV-6A (GS) and HHV-6B (Z-29) can infect highly purified primary fetal astrocytes in vitro. Infected cells showed cytopathic effects, forming giant syncytia. In dual immunofluorescence assays, the infected cells were detected by antibodies against the HHV-6 p41 nuclear antigen and glial fibrillary acidic protein, indicating that the infected cells are indeed astrocytes. PCR and Northern (RNA) blot analyses also confirmed that the astrocytes are infected by HHV-6. The progeny virus did not alter its host range and could reinfect T cells as well as primary astrocytes. These findings suggest that infection of primary human astrocytes may play a role in the neuropathogenesis of HHV-6.

Astrocytes↗

PubMed1996

Liver transplantation for haemophiliacs with hepatitis C cirrhosis.

BACKGROUND: Experience of liver transplantation in haemophiliacs with end stage hepatitis C liver disease is limited and particularly difficult questions are raised when there is also HIV infection. AIMS: This is the first report in Great Britain to describe the operative replacement therapy and initial outcome in four haemophiliacs with end stage HCV cirrhosis. PATIENTS: Two patients had factor VIII, one had factor IX, and one had factor X deficiency. One patient had also contracted HIV infection from factor replacement but had no AIDS defining illnesses. METHODS: Intraoperatively patients were given either factor VIII infusions, factor IX bolus, or fresh frozen plasma, according to formulae devised to calculate exact clotting factor requirements. Baseline preoperative coagulation studies included prothrombin time, activated partial thromboplastin time, fibrinogen concentrations, and factor VIII, IX, and X concentrations. Factor concentrations were then assayed at 12, 24, 48, and 72 hours postoperatively. RESULTS: Postoperatively all patients had coagulation factor concentrations sustained within the normal ranges by 72 hours unsupported (137, 125, 95, 104 IU/dl), representing de novo synthesis by the graft. Transfusion requirements during the operative and immediate post-transplant period were no greater than those of patients without clotting disorders. Two patients had episodes of bleeding postoperatively, one of which was fatal, occurring at the site of a previous untreated subdural bleed. In both instances the bleeding occurred in the presence of normal concentrations of clotting factor. The remaining three patients are at 6, 6, and 12 months post-transplant and remarkably improved clinically with sustained factor concentrations. One patient has evidence of graft dysfunction from HCV recurrence and all have evidence of recurrent viraemia with HCV on polymerase chain reaction studies. CONCLUSIONS: Orthotopic liver transplantation should be considered in haemophiliac patients with end stage liver disease from hepatitis C infection with or without concomitant HIV infection. Their clinical condition is likely to be greatly improved by orthotopic liver transplantation and the haemophilia cured with only a small risk of severe graft dysfunction from recurrent HCV infection.

Adult↗

PubMed1996

Acidic and basic FGFs dilate arterioles of skeletal muscle through a NO-dependent mechanism.

Fibroblast growth factors (FGFs) have been known to be potent stimulators of vascular endothelial cell proliferation and angiogenesis. Recent experimental evidence indicates that basic FGF (bFGF) is also involved in modulation of arterial pressure. In this study, we investigated the effects of acidic FGF (aFGF) and bFGF on muscle microcirculation using isolated arterioles and intact cremaster muscles of the at. In isolated microvessels, aFGF and bFGF (10(-12)-10(-8) M) significantly increased arteriolar diameter in a dose-dependent and time-dependent manner. This effect was abolished during inhibition of nitric oxide synthesis by NG-monomethyl-L-arginine (L-NMMA, 10(-4) M) but was not affected by indomethacin (10(-4) M), an inhibitor of the cyclooxygenase pathway of arachidonic acid metabolism. The vasodilation induced by FGFs was not observed in endothelium-denuded vessels. Furthermore, we studied microvascular hemodynamics in response to the growth factors in the cremaster muscle using intravital microscopy. Both aFGF and bFGF dilated arterioles of the intact cremaster muscle in a pattern similar to that observed in the isolated arterioles. At a concentration of 10(-10) M, aFGF caused a 19% increase in vessel diameter and 56% increase in blood flow. Administration of L-NMMA blocked by FGF-induced vasodilation and hyperemia. These results suggest that FGFs modulate blood flow in the skeletal muscle by acting on the endothelium of arterioles. The signaling mechanism of FGF-induced vasodilation involves the synthesis of nitric oxide by arteriolar endothelium.

Animals↗

PubMed1996

Children and cycle helmets -- the case against.

Much of the literature on child cycling accidents appears to blame the child as a victim, as though children's activities of playing and travelling were somehow wrong and that children are at fault when an adult drives a car over them. This adult-centred approach then leads to the idea that children should protect themselves with helmets, and that they are to blame if they are injured. However, adults who continue to hold the fantasy that helmets might be of value should know that the British Standard for cycle helmets protects only in a vertical fall of 1 m -- certainly not motor vehicle crashes. Thicker motor cycle helmets would give better protection but, of course, are heavier (and therefore unsaleable). Yet even with compulsory wearing helmets, more motor cyclists still die of head injuries than pedal cyclists. In the Newcastle study, five times as many child pedestrians died of road accidents as child cyclists. Convinced helmeteers should recommend all children playing or travelling in the streets to wear helmets (presumably heavy motor-cycle helmets). Slightly more sceptical proponents might prefer half of them -- in a randomized controlled trial. Car driving appears to have as serious health consequences as tobacco, alcohol and drugs, and to be as addictive (McCarthy 1992). Helmets are similar to filters in cigarettes -- they give the illusion of safety to both consumer and producer of the product, but the illusion is fatal. Yet, for their cardiovascular and mental health, children should have the freedom to cycle in safety around where they live. A profound change in the habits of adults is needed, rather than suits of armour for children.

Bicycling↗

PubMed1995