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Biomedical subjects

I F Young

Publications and source records attributed to I F Young.

17 recordsLinked to original sources
PubMed1998

Exposure to GB virus type C or hepatitis G virus in selected Australian adult and children populations.

BACKGROUND: The epidemiology and disease association for the GB virus type C (GBV-C) or hepatitis G virus (HGV) are poorly understood. STUDY DESIGN AND METHODS: This study describes the exposure rates to GBV-C/HGV in diverse Australian population groups by testing for current infection and evidence of past infection with a reverse transcriptase polymerase chain reaction and an anti-E2 enzyme-linked immunosorbent assay, respectively. Subjects included volunteer blood donors, hepatitis C antibody (anti-HCV)-positive donors, children, hemodialysis patients, pregnant women attending a prenatal clinic, injecting drug users (IVDUs), and adult hemophiliacs. RESULTS: Combined GBV-C RNA and E2 antibody prevalence was 6.5 percent (6/93) in children, 13.3 percent (75/565) in blood donors, 14 percent (14/99) in pregnant women, 22.5 percent (18/80) in hemodialysis patients, 80 percent (56/70) in anti-HCV-positive donors, 88.6 percent (31/35) in IVDUs, and 85.7 percent (54/63) in adult hemophiliacs. Children had the lowest antibody rate, 1.1 percent, whereas the rate was 10.8 percent for blood donors and rose to 45.7 percent for IVDUs, 57.1 percent for anti-HCV-positive donors, and 74.6 percent for hemophiliacs. In contrast, current infection rates were comparable for children, blood donors, and pregnant women (5.4, 2.6, and 6%, respectively), rising to 11.1 percent for hemophiliacs, 24.3 percent for anti-HCV-positive donors, and 48.6 percent for IVDUs. Ten of 12 blood donors had persistent viremia, while 2 had recent infections, 1 with apparent resolution. CONCLUSION: Exposure to GBV-C can commence at an early age, although ongoing exposure may also occur among adults with no apparent risk factors. GBV-C RNA positivity was not associated with abnormal plasma alanine aminotransferase levels among blood donors.

Adult↗
PubMed1997

Prevalence of hepatitis C virus and genotype distribution in an Australian volunteer blood donor population.

BACKGROUND: This study was undertaken to assess the prevalence of hepatitis C virus (HCV) antibody and RNA in first-time blood donors and to examine the HCV genotype distribution. STUDY DESIGN AND METHODS: A third-generation enzyme-linked immunosorbent assay (ELISA) was used to screen 34,725 donors for HCV antibodies. Donors who were repeatably reactive were tested in two immunoblot assays-a second-generation and a third-generation recombinant immunoblot assay-as well as by a polymerase chain reaction (PCR) assay. PCR-positive donors were genotyped. All samples were screened for alanine aminotransferase levels. RESULTS: The ELISA repeat reactivity rate was 0.55 percent. PCR testing showed that 69 (38%) of the 183 ELISA-reactive samples contained HCV RNA. The third-generation recombinant immunoblot assay identified all 69 viremic samples as antibody positive; however, only 63 tested positive on the second-generation immunoblot. The remaining six PCR-positive donors tested antibody-indeterminate to the core peptide. All six of these donors had HCV subtype 3a infections. Genotype distribution among 58 samples showed that 34 were type 1, of which 22 could be further subtyped as 1a (16) and 1b (6); 2 were 2a; 5 were 2b; and 17 were subtyped as 3a. Donors infected with 2b and 3a had reduced antibody reactivity to the NS4 and NS3 peptides only on the second-generation immunoblot. CONCLUSION: The prevalence of confirmed anti-HCV and viral RNA in new donors is 0.29 and 0.2 percent, respectively. The third-generation recombinant immunoblot assay was more sensitive than the second-generation immunoblot assay in detecting 2b and 3a HCV subtypes. The inclusion of the NS5 peptide in the third-generation recombinant immunoblot did not result in positive tests in any additional donors. Rather, the improvement was due to the increased detection of NS3 and, to a lesser extent, NS4 antibodies. Subtypes 1a and 3a were most prevalent in this population.

Antigen-Antibody Reactions↗
PubMed1996

Prevalence of hepatitis G virus in Queensland blood donors.

OBJECTIVE: To determine the prevalence of hepatitis G virus (HGV) carriage in Queensland blood donors. DESIGN: Cross-sectional survey with retrospective longitudinal study of HGV-positive donors. SETTING: Brisbane Red Cross Blood Bank, 1995. SUBJECTS: 100 consecutive blood donors attending the Blood Bank on two days in October 1995 and 20 blood donors with a raised plasma alanine aminotransferase (ALT) level on their last donation. OUTCOME MEASURES: Presence of HGV RNA by reverse transcription polymerase chain reaction (RT-PCR) in currently donated blood and in blood samples archived for up to 34 months. RT-PCR used two different reverse transcription methods and three different specific sets of primers and probes. RESULTS: Five of the 120 blood donors were positive for HGV RNA by all RT-PCR methods (four of the 100 with normal ALT levels [4%] and one of the 20 with raised ALT levels [5%]). Retrospective testing of archived samples showed that four of these five had been persistently HGV RNA-positive for at least two years, while the fifth had been HGV RNA-negative on two donations before becoming HGV RNA-positive. No risk factors were identified for this donor. CONCLUSIONS: A relatively large number of Queensland blood donors (4%) are persistently HGV RNA-positive.

Adult↗
PubMed1992

Predictive markers for hepatitis C antibody ELISA specificity in Australian blood donors.

The hepatitis C antibody reactivity rate in 91,748 blood donors tested using the ORTHO HCV C-100 ELISA system was 0.51%. Specificity of ELISA positive reactions was measured using a recombinant immunoblot assay (RIBA). The aim of this study was to identify markers in ELISA positive donors which were predictive of a RIBA positive result. Samples from 430 ELISA positive donors were tested by the first generation RIBA, RIBA-1, which incorporates two HCV peptides C-100 and 5-1-1. Fifty-five per cent (236) were positive and 19% (83) indeterminate. Multivariate analysis of gender, age, HCV ELISA OD ratio, alanine aminotransferase (ALT) status and hepatitis B core antibody (anti-HBc) status identified age, magnitude of HCV ELISA OD ratio and anti-HBc status as the only independent predictors of a positive RIBA-1 result. The relative odds of being RIBA-1 positive were 4.6-fold (95% CI 1.3-16.4) higher among donors aged 25-34 years compared with donors less than 25 or greater than 44; 6.1-fold (2.1-17.9) higher if the donor was anti-HBc positive and 273.4-fold (30.9-2417) higher if the HCV ELISA OD ratio was greater than 5.98 compared to those with a ratio less than 1.77. Seventy-eight of the 83 RIBA-1 indeterminates were tested on the second generation RIBA, RIBA-2, which includes two additional HCV peptide, C22 and C33c. Thirty-one per cent (24) were positive and 41% (32) were negative.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

ABO incompatible blood transfusion.

Four cases of ABO incompatible blood transfusion are presented which occurred over a 3-year period and resulted in marked clinical variation. In each instance the error leading to the transfusion resulted from the incorrect identification of either the patient, the crossmatch sample or the donations. These cases not only highlight the problems in the clinical recognition of ABO incompatibility but indicate a need to shift emphasis from refining crossmatch methodology to the strict following of standard established protocols for transfusion. It is of paramount importance to guarantee the failsafe identification of blood specimens, donations and recipient to minimize the possibility of accidents due to human error.

ABO Blood-Group System↗
PubMed1988

Surrogate testing for non-A, non-B hepatitis in Queensland, Australia: an ALT microtitre tray method for screening blood donors.

The estimation of plasma alanine aminotransferase (ALT) has been proposed as a surrogate test to identify potential non-A, non-B hepatitis carriers in blood donor populations. This report describes an ALT screening procedure which uses wells of microtitration trays as reactant vessels. The method utilizes a rate reading photometer, is economical and conveniently fits into the routine workflow. Within-batch and between-batch precision was 4.1% and 6.3% at enzyme concentrations of 49 IU/I. Results of testing 29,675 healthy blood donors gave values which ranged between 1.0 IU/I and 214 IU/I. A study of 762 donations showed a significant difference in mean ALT values between males and females (p less than 0.01). When a cut-off value of 46 IU/I was used, 2.5 percent of donations were considered unsuitable for transfusion. The medico-legal implications that may arise from the introduction of this screening test into the routine work flow are discussed.

Alanine Transaminase↗
PubMed1987

Albumin solutions--their production and quality control.

Analysis of all clinical reactions (complaints) reported to CSL in the past decade has revealed that "hypotension syndrome" continues to be the predominant side effect of infusion of albumin solutions. Although the incidence of clinical reactions to albumin solutions reported to CSL is approximately 1 in every 20,000 bottles issued, the virtual elimination of PKA from SPPS has not reduced the number of adverse clinical reports received by CSL. It is concluded that factors other than PKA contamination are responsible for hypotensive effects during or after infusion of albumin solutions. Other possible causes of "hypotension syndrome" are discussed.

Humans↗
PubMed1985

A device for the nondestructive decontamination of large volumes of infected egg waste.

A device for the decontamination of large numbers of infected eggs which remain as by-products of vaccine production is described. Homogenates of infected eggs were heated to 60 degrees C and maintained at that temperature for 3 h in a specially constructed recirculation tank. The infectivity of all detectable influenza viruses and more than 99% of the bacteria associated with the homogenates was destroyed by this procedure. Eggshell material was separated from the proteins present in the homogenate at the end of the heating cycle by means of a cyclone separator. The proportions of all the amino acids, except cystine, in the proteins remaining in the suspension after the heating cycle were similar to that normally present in whole embryos.

Animal Feed↗
PubMed1982

Pruritus and severe iron deficiency in polycythaemia vera.

Six patients diagnosed as having polycythaemia vera had severe pruritus that persisted despite adequate haematological control. Iron supplementation was given when iron deficiency was noted in all six patients. The pruritus began to improve two to 10 days after the start of treatment and had completely disappeared after two to three weeks. In three patients the iron treatment was stopped because of unacceptably high haemoglobin concentrations; the pruritus recurred. Since chronic iron treatment may result in increases in red cell mass indiscriminate use of iron in patients with polycythaemia vera and pruritus is not advocated. Nevertheless, in patients with severe symptoms and evidence of iron deficiency treatment with iron, continuing for two to three weeks after the symptoms have abated, may be beneficial.

Aged↗
PubMedDate not supplied

Effect of virucidal heat treatment on proteins in human factor VIII concentrates.

Intermediate-purity and fibrinogen-poor factor VIII concentrates were heated in the lyophilized state at 60 degrees C for up to 72 hours to inactivate blood-borne viruses. The effect of heat treatment on factor VIII, von Willebrand factor (vWf), and other proteins present in the concentrates (albumin, fibrinogen, fibronectin, IgG, and IgM) was evaluated. Heat-induced protein aggregation, particularly of fibrinogen and fibronectin, occurred within 48 hours in the intermediate-purity concentrates and correlated well with decreased solubility of these products. Heated fibrinogen-poor concentrates were readily soluble and did not show protein aggregation even after 72 hours at 60 degrees C. Neither concentrate developed detectable neoantigens when tested against antisera to whole human plasma and to heated and unheated concentrates. Aggregation of the vWf molecule, detected by altered mobility in crossed immunoelectrophoresis and multimeric analysis in SDS agarose gels, occurred in heated intermediate-purity concentrates but not in fibrinogen-poor concentrates. Thus, higher-purity factor VIII concentrates withstand heat treatment better than concentrates that contain greater levels of contaminating proteins, particularly fibrinogen.

Chromatography, Gel↗