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Biomedical subjects

B T Colvin

Publications and source records attributed to B T Colvin.

At least 37 records · Page 2Linked to original sources
PubMed1993

A 7-year analysis of anti-Gag (p17 and p24) antibodies in HIV-1-seropositive patients with haemophilia: immunoglobulin G titre and avidity are early predictors of clinical course.

OBJECTIVE: To study the humoral immune response to HIV-1 p17 and p24 Gag proteins longitudinally and assess any prognostic value. DESIGN AND METHODS: Fifteen HIV-1 infected patients with haemophilia were asymptomatic at entry to the study in 1986. Each patient was monitored at 6- to 12-month intervals for up to 7 years for p17 and p24 immunoglobulin (Ig)G titres, p17 IgG avidity, total IgG, p24 antigenaemia and CD4 cell counts. Results were correlated with the clinical course. RESULTS: Between 1986 and 1993, six of the patients developed CD4 cell counts below 200 x 10(6)/l (AIDS patients) while nine retained counts above this level (asymptomatic patients). All AIDS patients were characterized by declining IgG titres to p17 and p24 from 1986-1987 onwards. A reduction in specific p17 and p24 IgG preceded, by at least 3-4 years, the onset of CD4 cell depletion (< 200 x 10(6)/l). These six patients also had significantly lower p17 IgG avidity than the asymptomatic patients throughout the study. CONCLUSION: Titres of p17 and p24 IgG appeared to alter in the same manner. A progressive reduction in IgG titres and a low p17 IgG avidity were earlier predictors of disease progression than CD4 cell counts or p24 antigenaemia.

Adult↗
PubMed1993

A longitudinal study of the IgG antibody response to HIV-1 p17 gag protein in HIV-1+ patients with haemophilia: titre and avidity.

The IgG response to HIV-1 p17 gag protein was studied for up to 6 years in 12 HIV-1-infected patients with haemophilia, who had seroconverted between 1982 and 1985. To assess any prognostic value, p17 IgG titres were compared with p24 IgG titres, CD4 cell counts and p24 antigenaemia. p17 IgG avidity index was also examined. A strong similarity was found between the IgG titre to HIV-1 p17 and that to p24. In patients who developed AIDS the decline in p17 IgG titres could precede by several years the drop in CD4 cells to under 200 cells/microliters; whereas some long-term asymptomatic patients (CDCII) had increasing p17 IgG titres and stable CD4 cell counts. Declining p17 and p24 IgG titres were not always associated with an increase in p24 antigenaemia. IgG titres were found to be better predictors of disease progression than CD4 cell counts or p24 antigenaemia. Patients who developed AIDS during the study were also characterized by a lower p17 IgG avidity than patients who remained asymptomatic. This result suggests that IgG avidity could have prognostic relevance and be of importance for host resistance to AIDS onset.

Adult↗
PubMed1992

Decline in CTL and antibody responses to HIV-1 p17 and p24 antigens in HIV-1-infected hemophiliacs irrespective of disease progression. A 5-year follow-up study.

CTL and antibody responses to HIV-1 p17 and p24 antigens were monitored from 1986-1991, in 4 hemophiliacs. The patients had been infected with HIV-1 between 1980 and 1984. Two patients have remained asymptomatic while two progressed to AIDS in 1990. CTL were boosted by culturing with peptides from p17 aa 86-115, or p24 aa 265-279; and aa 270-373 or PHA. Lysis was measured on autologous or allogeneic targets pulsed with peptides or infected with recombinant vaccinia virus carrying HIV-1 gag or influenza A matrix genes. Antibodies to p17 and p24 were tested by ELISA using peptides and by Western blotting. High levels of CTL activity to p17 and p24 antigens could be generated only with lymphocytes from the two asymptomatic patients between 1986 and 1989, but these responses were absent in 1990 and 1991. Antibodies to p17 peptides disappeared in parallel with CTL activity. Antibodies to some p24 peptides also declined but most patients retained activity to others. In all patients a > or = 3-fold increase in CD8+ cell numbers occurred over time and accompanied the decline of CTL and antibody responses. The loss of CTL and p17 antibodies occurred irrespective of whether patients remained asymptomatic or progressed to AIDS in the intervening two years.

Cell Line, Transformed↗
PubMed1988

Effect of intravenous immunoglobulin on a spontaneous inhibitor to factor VIII.

A 71-year-old woman with a spontaneous anti-factor VIII inhibitor fractured her right wrist and 2 months later her left femur. She received treatment with porcine factor VIII for the first fracture and developed a secondary anti-porcine antibody response (from 10 to 200 Bethesda units). Following the second fracture she received intravenous immunoglobulin (i.v. IgG) (0.4 g/kg day for 5 days) in an attempt to reduce antibody activity. Despite further treatment with porcine factor VIII, the antibody level declined instead of rising as expected and the anti-human antibody activity also declined. We were not able to demonstrate neutralizing activity to her antibody but did demonstrate a reduced helper: suppressor ratio and reduced B-cell numbers and function after treatment with i.v. IgG. These changes were transient and as B-cell function improved over the following 4 months, her anti-human activity returned toward its previous level. Anti-porcine activity remained at its previous low level. We speculate that one of the mechanisms of action of i.v. IgG may be a direct cellular effect influencing both T-suppressor and B-lymphocyte function.

Aged↗
PubMed1987

A prospective study of cryoprecipitate administration: absence of evidence of virus infection.

In a prospective study of cryoprecipitate administration to patients who had never received large pool concentrates, no evidence of hepatitis or HIV infection was detected in a follow up period of one year. Following the introduction of screening of blood donors for anti-HIV in the UK in October 1985 the use of cryoprecipitate in selected cases should be reconsidered.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Heat-treated NHS factor VIII concentrate in the United Kingdom--a preliminary study.

Three patients who have been given intermediate purity NHS heat-treated factor VIII concentrate have been followed prospectively for 7-10 months. None had previously received more than six donor units of blood products containing factor VIII. There were no clinical side effects from concentrate administration, haemostasis was satisfactory and no patient developed clinical or laboratory evidence of hepatitis or HTLV III/LAV infection. Heat treatment resulted in the loss of slightly more than 20% of factor VIII activity but in vivo recovery of factor VIII and half disappearance times were within the expected range.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Myocardial infarction with normal coronary arteries and factor XII deficiency.

A 17 year old girl had a myocardial infarction. Three days later coronary angiography showed an occlusive thrombus in the circumflex and anterior descending arteries. The coronary arteries themselves appeared to be normal, and this was confirmed at repeat angiography three months later. Tests of haemostasis showed a deficiency of factor XII.

Adolescent↗
PubMed1985

Thrombocytopenia.

Thrombocytopenia is a common haematological abnormality in pregnancy which has important implications for both mother and fetus. It may occur as part of the pathophysiology of pregnancy itself, but in many cases pregnancy is superimposed on a background of haematological disease. Failure of platelet production remains a difficult and dangerous problem to manage while the outlook for non-immune platelet destruction has improved as a result of a clearer understanding of the haemostatic changes taking place in the pregnant woman. Immune-mediated thrombocytopenia is now also better understood because of recent advances in antibody detection and quantitation but it has been difficult to translate this new knowledge into the planning of well considered treatment strategies. The administration of high-dose ivIgG to either mother or fetus shows promise as a new and safer method of managing delivery and neonatal life in autoimmune and alloimmune thrombocytopenia but further evaluation is necessary before the indications for giving ivIgG are clear. Close cooperation between obstetricians, haematologists and scientific staff is essential if the best treatment for the thrombocytopenia of pregnancy is to be given.

Adult↗
PubMed1984

Does calcium contribute to the effectiveness of a coagulum for pyelolithotomy?

Adding calcium to a mixture of thrombin and fibrinogen increased the breaking strain of the resultant coagulum by 10-fold, but did not significantly reduce the length to which it could be stretched. There was no detectable change in the time taken for the coagulum to dissolve in urine. Simulation pyelolithotomies were performed on pig kidneys containing ball-bearings which represented calculi. Coagula formed with calcium were significantly more effective at retrieving the ball-bearings than coagula without calcium. It is concluded that the ideal coagulum formula should include 1 mmol of calcium.

Animals↗
PubMed1983

Experience with highly purified porcine factor VIII in a patient with haemophilia A and a factor VIII inhibitor.

Highly purified porcine factor VIII has been advocated for the treatment of bleeding episodes in patients with haemophilia who have inhibitors to factor VIII. This approach has been successful in a patient with an intermediate potency inhibitor showing little cross-reactivity to porcine material. As in some other reported cases, a severe allergic reaction occurred on one occasion but did not preclude the subsequent use of the porcine concentrate in carefully controlled conditions.

Adult↗
PubMed1982

Sideroblastic anaemia with iron overload presenting as an arthropathy.

We report on 2 patients with sideroblastic anaemia an secondary iron overload whose presenting symptom was an arthropathy of small an large joints. One patient had marked spinal symptoms which were severe enough to suggest ankylosing spondylitis, and the pattern of arthritis in the other resembled seronegative rheumatoid arthritis. We believe these to be the first cases described of an arthropathy associated with iron overload secondary to sideroblastic anaemia.

Adult↗
PubMed1981

The role of intensive plasma exchange in the prevention and management of haemorrhage in patients with inhibitors to factor VIII.

A strategy for the prevention and management of haemorrhage in patients with inhibitors to factor VIII by intensive plasma exchange and human factor VIII infusion is described. The advantages and disadvantages of this approach are discussed in the light of the authors' experience with the technique and the alternative methods of treatment described in the literature.

Adult↗