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Biomedical subjects

R B Heath

Publications and source records attributed to R B Heath.

At least 55 records · Page 3Linked to original sources
PubMed1984

Improving the varicella-zoster virus: IgG radioimmunoassay procedure by the use of purified antigen.

The indirect radioimmunoassay (RIA) for detecting and assaying IgG class antibodies against varicella-zoster virus (VZV) can be improved by simple purification of the viral antigen. This is achieved by reducing binding to cellular components present in crude antigens. The purified antigen is particularly useful for testing sera that either bind excessively to normal control antigen or give equivocal results when crude antigens are used.

Antibodies, Viral↗
PubMed1984

Antibody against viruses in maternal and cord sera: non-specific inhibitors are found to higher titre on the maternal side of the circulation.

Pregnancies were identified in which maternal IgG antibodies against rubella virus were not detectable by single radial haemolysis. Twenty paired maternal/cord sera were then tested for haemagglutination-inhibiting (HI) activity against rubella virus without kaolin pretreatment of the sera. In the absence of specific antibody, the HI activity observed could thus be ascribed to the effect of non-specific inhibitors. The HI activity in maternal sera was significantly (P less than 0.001) higher than that in cord sera. The 20 pairs of sera were similarly tested against a bunyavirus, an alphavirus and a flavivirus, both with and without kaolin pretreatment. The results showed non-specific inhibitors were found to higher titre in maternal sera, with the difference being statistically significant (P less than 0.001) for each of the three viruses.

Absorption↗
PubMed1984

Analgesic effects of butorphanol in horses: dose-response studies.

The analgesic effects of butorphanol (0.05, 0.1, 0.2, and 0.4 mg/kg), pentazocine (2.2 mg/kg), and butorphanol vehicle (0.04 ml/kg) were observed in 6 horses. These horses were instrumented to measure response objectively to painful superficial and visceral stimuli. The tested drugs were given IV according to a Latin square design. After preinjection base-line measurements were made, the analgesic effects were observed at 15 and 30 minutes and then at 30-minute intervals until postinjection minute 240. Analgesic effects of butorphanol were dose-related, with durations between 15 and 90 minutes. Duration of analgesia after pentazocine (2.2 mg/kg) was given was between 15 and 30 minutes. When compared with pentazocine, the 0.4 mg/kg dose of butorphanol provided a more intense and longer period of analgesia. A butorphanol dose of 0.2 mg/kg IV appears optimal. On a dose-body weight basis, the potency of butorphanol was 10 to 17 times that of pentazocine. Behavioral side effects were noted with both agents and were dose-related.

Analgesia↗
PubMed1984

Effects of butorphanol, flunixin, levorphanol, morphine, and xylazine in ponies.

The analgesic and behavioral effects of butorphanol (0.22 mg/kg), flunixin (2.2 mg/kg), levorphanol (0.033 mg/kg), morphine (0.66 mg/kg), and xylazine (2.2 mg/kg), given IM were observed in 8 ponies. These ponies were instrumented to measure response objectively to painful superficial and visceral stimuli. Effects on the cardiopulmonary system and rectal temperature also were evaluated in 6 of these ponies. Observations were conducted before drug injection (base-line values) and after injection at 30, 60, 120, 180, and 240 minutes. Xylazine provided the highest pain threshold for the first 60 minutes and a sedative effect for 105 minutes. The effects for superficial pain and visceral pain persisted 3 hours and 4 hours, respectively. Morphine produced good analgesia for superficial pain (30 minutes), whereas butorphanol provided good effect for visceral pain (4 hours). A slight degree of analgesia for visceral pain was obtained after morphine (1 hour) and levorphanol (4 hours); flunixin did not induce analgesia. Butorphanol, levorphanol, and morphine stimulated motor activity. Behavioral effects did not occur after flunixin was given. Xylazine decreased systolic, diastolic, and mean blood pressures. Marked increases in these pressures, heart rate, and respiratory rate were observed after morphine was given. Changes of central venous pressure, rectal temperature, and blood gas values remained within base-line limits after both drugs were given. Butorphanol increased heart rates for 1 hour; flunixin and levorphanol did not alter any of the above values.

Analgesia↗
PubMed1983

Rubella screening.

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Antibodies, Viral↗
PubMed1983

A comparison of indirect immunofluorescence and radioimmunoassay for detecting antibody to varicella-zoster virus.

Immunofluorescence (IF) and radioimmunoassay (RIA) were found to be more sensitive methods than complement fixation (CF) for detecting antibody to varicella-zoster (V-Z) virus. RIA yielded titres about 30 times greater than those obtained by IF, but for screening purposes RIA was only about six times more sensitive since the minimum serum dilutions that could be tested were 1/100 and 1/16 respectively. When 539 sera from subjects of different ages were screened for V-Z antibody, IF and RIA gave concordant results with 527 specimens (98%). When 19 patients were tested who had not previously had varicella but were experiencing primary infection with herpes simplex (HS) virus, crossreacting antibodies to V-Z antigens were detected in six patients by IF but in only two of these by RIA. IF and RIA are preferable to CF as tests for immune status because of their greater sensitivity, but weak positive reactions caused by presumptive low titres of homologous antibody or by higher titres of heterologous antibody can occur in one or both tests. Such reactions could cause difficulty in assessing the need for vaccine or for specific immune globulin, and in interpreting the response to vaccination.

Antibodies, Viral↗
PubMed1982

Specific IgM class antibody production following infection with cytomegalovirus.

Specific IgM class antibody production was studied in different groups of patients with characterized cytomegalovirus (CMV) infections using a radioimmunoassay (RIA). In pregnant women, IgM antibodies were detected only following primary infection and generally persisted less than 4 months. The demonstration of CMV-specific IgM during pregnancy is therefore diagnostic of recent primary CMV infection. In patients with symptomatic CMV infections, the appearance of IgM antibody was shown to be closely related to the onset of symptoms and coincided with production of complement fixing (CF) antibody. IgM antibodies were at maximum levels 3-4 weeks after presentation but generally declined to low or undetectable levels by 3-4 months. The significance of the results of testing for CMV-specific IgM in relation to clinical and other serological findings in these patients is discussed. IgM antibody production was also demonstrated in renal transplant patients with primary infections and in 6 of 21 recipients with secondary infections. In both groups the antibodies became detectable 3-6 weeks after transplantation but the titres were much higher following primary infection. IgM antibodies persisted throughout follow-up periods of up to 2 years after transplantation in some cases.

Antibodies, Viral↗
PubMed1982

Antibody against viruses in maternal and cord sera: specific antibody is concentrated on the fetal side of the circulation.

Paired maternal and cord sera from 100 pregnancies were tested for antibodies against herpes simplex virus, measles virus and respiratory syncytial virus by complement fixation and for antibodies against rubella virus, influenza A virus and influenza B virus by haemagglutination-inhibition. For four viruses (herpes simplex, measles, respiratory syncytial and rubella) higher levels of antibody were found in cord than in maternal sera. There was no difference between maternal and cord serum titres against influenza B virus but significantly higher levels of antibody against influenza A virus were found in maternal sera than in cord sera. This discrepancy was investigated by measuring antibodies against the surface antigens of influenza A by a complement fixation technique, and by single radial haemolysis. Both methods showed a preponderance of virus-specific antibody in cord sera. We conclude that IgG antibodies against most, if not all, viruses are concentrated on the fetal side of the circulation, but the conventional haemagglutination-inhibition techniques may fail to detect this difference.

Antibodies, Viral↗
PubMed1982

The postnatal acquisition of factors which affect the influenza haemagglutination-inhibition test.

Levels of maternally transferred antibodies against the surface antigen of the A/Texas/1/77 strain of influenza virus showed the expected decline during infancy when measured by complement fixation (CF). However, this decline was not observed when these antibodies were measured by haemagglutination-inhibition (HI). It has been postulated that this discrepancy is due to the acquisition, in the early days of life, of non-specific serum factors which increase the HI activity of sera. The levels of these factors were determined indirectly by calculating HI:CF ratios and it was shown that the factors are rapidly acquired by children between the fifth and twentieth week of life.

Adult↗
PubMed1982

Comparison of enzyme-linked immunosorbent assay, radioimmunoassay, complement fixation, anticomplement immunofluorescence and passive haemagglutination techniques for detecting cytomegalovirus IgG antibody.

The radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques were found to be comparable in sensitivity and specificity for detecting cytomegalovirus IgG antibody, and 10 to 100 times more sensitive than complement-fixation (CF), anticomplement immunofluorescence (ACIF) and passive haemagglutination (PHA). In screening tests for antibody, the frequency of false-positive and -negative results was 0.6% for RIA and ELISA, 1.5% for CF, 1.6% for ACIF and 3.6% for PHA. PHA was the least satisfactory test, largely because of technical problems. Cytomegalovirus (CMV) infection is an important cause of congenital brain damage and is also a major complication of both prolonged immunosuppressive therapy, especially in patients with organ transplants, and multi-donor blood transfusions. For serological diagnosis of infection, as well as for screening for antibody in patients and in blood donors, the solid-phase indirect radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques offer distinct improvements in sensitivity over previous methods. Although the principle of both tests, based on the detection of antigen-antibody reactions by means of a labelled anti-antibody, is the same, each possesses its own particular technical advantages and disadvantages, and both require their own expensive equipment for the reading of the results. There is still a lack of data on how they compare in sensitivity and specificity. The present study was undertaken to compare the two methods for the detection of CMV IgG and to evaluate them against the older techniques of complement-fixation (CF), passive haemagglutination (PHA) and anticomplement immunofluorescence (ACIF).

Antibodies, Viral↗
PubMed1981

The development and evaluation of a solid-phase radioimmunoassay (RIA) procedure for the determination of susceptibility to varicella.

The development of a sensitive solid-phase radioimmunoassay (RIA) procedure for the detection of specific antibodies against varicella-zoster (VZV) is described. The test proved to be about 200 times more sensitive than complement fixation (CF) and far more efficient at detecting low levels of antibody in the sera of individuals with past history of varicella. It is suggested that this RIA-VZV test would be suitable for distinguishing between individuals who are either immune or susceptible to varicella, which could be useful in a variety of clinical situations but particularly in current and future evaluations of varicella vaccines.

Antibodies, Viral↗
PubMed1981

Comparison of radioimmunoassay and the gel filtration technique for routine diagnosis of rubella during pregnancy.

Radioimmunoassay (RIA) for rubella-specific IgM antibodies was compared with haemagglutination-inhibition (HI) in conjunction with gel filtration for the diagnosis of rubella infection in pregnant women during a 1-year period. In total 476 women were investigated of whom 221 were tested for rubella IgM. Both techniques gave positive results with 64 sera, and RIA alone with one additional serum. Difficulties associated with the removal of non-specific HI activity were encountered with four sera all of which were negative by RIA. RIA was found to have practical advantages over the gel filtration method but is at present technically more difficult to perform.

Antibodies, Viral↗
PubMed1980

Persistence of high titre antibodies to the early antigens of cytomegalovirus in pregnant women.

Serial serum samples were obtained from 45 pregnant women who had been shown to possess complement fixing (CF) antibodies to cytomegalovirus (CMV) during a previous pregnancy. The serial samples were tested for antibodies against the early antigens (EA) and complement fixing antigens of CMV. All of the 45 women still possessed CF antibodies at the commencement of their next pregnancy. Six of the 45 women (13 per cent) lacked detectable IFA-EA antibodies whilst 19/45 (42 per cent) women possessed only low titres (less than or equal to 64) of these antibodies. However, 20/45 (44 per cent) women possessed high titre (greater than or equal to 128) antibodies despite having experienced their primary CMV infection many months previously. It is concluded that antibodies to the EA OF CMV are not as transitory as has been suggested and that their presence, even at high titre, in a serum sample from a pregnant woman cannot be taken as presumptive evidence of recent primary infection with this virus.

Antibodies, Viral↗
PubMed1980

The role of host responses in the recovery of mice from Sendai virus infection.

The antiviral responses in mice to intranasal inoculation with Sendai virus are described. To investigate the relative importance of the humoral, cell-mediated and interferon responses, the pathogenesis of this infection was studied in animals which were immunocompetent, T cell-deprived or immunosuppressed with cyclophosphamide. Treatment with cyclophosphamide converted the mild, self-limiting infection observed in immunocompetent mice into a severe and frequently lethal pneumonic disease. This was associated with an enhanced interferon response but no detectable antibody or cell-mediated immune response. T cell-deprived mice suffer an infection of intermediate severity associated with an increased interferon response, a normal humoral immune response and no cell-mediated immune response. The implications of these results in relation to the role of the antiviral responses in recovery from Sendai virus infection are discussed.

Animals↗
PubMed1980

A prospective study of primary cytomegalovirus infection in pregnant women.

During a four year study, sera were obtained from 5575 women attending for antenatal care and 3188 (57.2 per cent) were shown to possess complement fixing antibodies to cytomegalovirus (CMV). A total of 1608 seronegative women were followed to term and 14 (0.87 per cent) primary CMV infections occurred in either the second or third trimester. Transplacental spread of CMV occurred in 3 out of 12 (25 per cent) of the 14 babies born to infected mothers. All 14 babies were apparently normal at birth but short term clinical follow-up has already revealed that one child has impaired hearing whilst another is microcephalic. The women were also monitored serologically throughout pregnancy for evidence of rubella infections. Only 12 infections were detected and 7 of these occurred during the large rubella epidemic of 1978. Of the 10 pregnancies which were allowed to proceed to term, transplacental spread of rubella virus occurred in 1 out of 7 (14 per cent). During this study period, CMV infections occurred as frequently as did rubella infections. We therefore conclude that, apart from those years when extensive epidemics occur, many more pregnant women are infected with CMV than with rubella virus.

Cytomegalovirus Infections↗