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Biomedical subjects

J A Paul

Publications and source records attributed to J A Paul.

18 recordsLinked to original sources
PubMed1996

Effect of posture on hip joint moment during pregnancy, while performing a standing task.

In this paper the combined effect on reactive hip joint moment due to changes in (1) segment mass, (2) trunk centre of mass, and (3) working posture during pregnancy was estimated, and the relative contributions of these three changes to the change in the moment were assessed. The situation studied concerned standing work at a table. Sixteen women were studied monthly during pregnancy. The working posture was assessed by two-dimensional photographic posture recording and description. Body dimensions were measured to assess segment characteristics. A two-dimensional static model was used to estimate the reactive hip joint moment at 10, 20, 30 and 40 weeks of pregnancy. Between 10 and 40 weeks of pregnancy the moment increase was 52 Nm, i.e. the load at 40 weeks of pregnancy is 2.8 times the load at 10 weeks of pregnancy. On average half of this increase was due to postural changes. Changes in segment mass, trunk centre of mass, and the interaction between the three changes accounted for rougly 10, 20 and 15% of the load increase respectively. The increase in reactive hip joint moment may be minimized by preventing adverse postural changes, and optimizing the posture to reduce the contribution of changes in body weight (distribution).

Journal Article↗
PubMed1995

The immunogenicity of reassortants of the cold-adapted influenza A master strain A/Ann Arbor/6/60 is determined by both the genes for cold-adaptation and the haemagglutinin gene.

Two surface antigen segregants were prepared by co-infection of chicken embryo kidney cell cultures with reassortants of the cold-adapted influenza A master strain A/Ann Arbor/6/60-ca (H2N2) possessing the surface antigens of A/Queensland/6/72 (H3N2) and A/Hong Kong/123/77 (H1N1) and other genes that were common to the master strain. The segregants were shown by serological tests to possess H3N1 and H1N2 surface antigens but it was not possible to determine the presence of H1 or N1 genes by single-stranded RNA polyacrylamide gel electrophoresis. The immunogenic properties of A/Queensland/6/72-ca and H3N1 segregant CR6/35/2/9 were compared by immunising mice intranasally with graded doses of each virus twice at an interval of 3 weeks and then challenging with the wild-type A/Queensland/6/72 (H3N2). Clearance of the challenge virus occurred in mice immunised with the same vaccinating dose, indicating that the immunogenicity of both the ca H3N2 and H3N1 viruses was identical and similar findings were obtained for mice immunised with A/Hong Kong/123/77-ca and the H1N2 segregant CR6/35/1/19 and challenged with the wild-type A/Hong Kong/123/77. Therefore, there appears to be a good correlation between immunogenicity and the inheritance of the haemagglutinin gene.

Adaptation, Physiological↗
PubMed1995

Pregnant women and working surface height and working surface areas for standing manual work.

Physically loading aspects of work may have adverse effects on the health of both the pregnant woman and the unborn child. Improving the fit between the pregnant woman and the workplace layout contributes to minimizing the load associated with given tasks. The aim of this paper is to evaluate two layout aspects for standing manual work, namely working surface height and working surface areas, for the condition of pregnancy. Two approaches were used. (1) The effects of changed body dimensions were evaluated with regard to (a) fit problems while working at a workplace in accordance with common guidelines and (b) the validity of assumptions of these guidelines. (2) The appreciation of relevant aspects of workplace layout at a specific manual task was assessed. Twenty-seven women were examined in pregnant and non-pregnant conditions. The first approach showed that fit problems are likely: guideline working surface height is just (2-7 cm) under the most protruding abdominal point, and areas based on non-pregnant abdominal depth are relatively large in pregnant condition. Further, existing methods to assess working surface areas have various assumptions that are not valid in pregnant condition. The second approach showed that at a specific manual task, women in late pregnancy preferred a considerably lower table height than the common guideline heights. Possibly, abdominal height becomes a relevant design factor with regard to working surface height during pregnancy. The task position on the working surface at which effort started became closer to the table edge due to pregnancy. Both approaches show that common guideline working surface heights for manual work, and working surface areas assessed in non-pregnant condition seem not suitable in pregnant condition.

Journal Article↗
PubMed1995

The World Bank, pensions, and income (in)security in the global south.

The authors describe and analyze recent reductions and reorganizations of public pension programs in Latin America, as well as trends in pensions in the global South more broadly. They consider the role of the World Bank in the current pension "reform" process and situate the Bank's policies in the context of privatization, reduction of social budgets, and other aspects of structural adjustment. Chilean pension changes are analyzed in particular, showing that even by the Bank's criteria, the reforms have not been successful. The authors then discuss pension changes in China, where the World Bank is also deeply involved. The article concludes with the consideration of a number of arguments about pensions and support mechanisms in later life--including family support and means-tested welfarism--and argues in favor of global policy approaches, such as globally funded pensions and full access by older persons to productive and remunerated labor.

Aged↗
PubMed1994

Standing working posture compared in pregnant and non-pregnant conditions.

During pregnancy, an increase in body weight occurs together with changes in body weight distribution and in fit between body dimensions and workplace layout. These changes may cause alterations in working posture which may, in turn, have adverse consequences for the biomechanical load on the musculoskeletal system and so increase the risk of musculoskeletal disorders. Using photographic posture registration, the standing working posture was studied in 27 women during the last stage of pregnancy and after delivery (the experimental group). The women performed an assembly task while standing at various workplace layouts. The postural differences between the pregnant condition and the non-pregnant condition were studied and the effect of the various workplace layouts assessed. Ten non-pregnant controls were also studied twice to establish the effect of the time interval between the measuring occasions. We found that the women of the experimental group stood further from the work surface in the pregnant condition compared to the non-pregnant condition, the hips were positioned more backwards, and, in order to reach the tesk, they increased the flexion of the trunk, increased the anteflexion of the upper arms, and extended the arms more. At the workplace layout in which the work surface height was self-selected, the postural differences due to pregnancy were smallest or even absent, compared to the postural differences in the other workplace layouts studied. Ergonomists and workers in occupational health services should be alert to the consequences for the biomechanical load on the musculoskeletal system and the risk of development of health complaints caused by postural changes due to pregnancy. An adjustable workplace layout may prevent some problems.

Adult↗
PubMed1994

Work load and musculoskeletal complaints during pregnancy.

OBJECTIVES: Many pregnant women have musculoskeletal complaints, the onset and aggravation of which are thought to be associated with their activity or work postures. The purpose of this paper was to obtain more insight into the influence of pregnancy on the load of the musculoskeletal system at work to provide a better basis for preventing complaints. METHODS: To this end, literature pertinent to a model called "work load of the musculoskeletal system" was reviewed. The model was developed to describe how work contributes to musculoskeletal complaints. RESULTS: It was found that pregnancy causes changes in a worker's characteristics. These changes can lead to changes in the work situation, activity pattern, and postural characteristics and possibly result in a change in work load. In addition, physical changes such as weight gain increase the work load in a given posture. The load-bearing capacity of the musculoskeletal system decreases due to pregnancy. CONCLUSIONS: The changes in load and the decrease in load-bearing capacity singly or simultaneously increase the risk of musculoskeletal complaints. The multifactorial cause of musculoskeletal complaints during pregnancy reveals various possibilities for prevention.

Biomechanical Phenomena↗
PubMed1993

Two-dimensional photographic posture recording and description: a validity study.

Posture recording and description is necessary to yield data by which postural load can be assessed. In this paper an inexpensive and simple method to gather these data is described, ie two-dimensional (2-D) posture recording and description by means of photography. A disadvantage of this method, perspective error, is discussed and guidelines are given to reduce it. The validity of the method was experimentally tested for a situation slightly conflicting with some guidelines, ie recording of the whole body, with a small distance between camera and subject. For this purpose posture recording with 2-D photography was compared with posture recording by means of a three-dimensional optoelectronic system (Vicon). In general, 2-D photographic posture recording and description is a valid method as long as some guidelines for reduction of perspective error are followed.

Journal Article↗
PubMed1992

An immunohistochemical study of phospholipase A2 in peripheral nerve during Wallerian degeneration.

Antiserum raised against purified Crotalus adamanteus venom phospholipase A2 (PLA2) was used to localise the enzyme in normal and crushed sciatic nerve to determine the effect of nerve trauma on PLA2 distribution in the PNS. The tissue was Bouin's fixed, and stained immunohistochemically using the Vectastain ABC technique. Anti-PLA2 antiserum showed weak reactivity with normal rat myelin, while only 'resident' macrophages stained in normal mouse sciatic nerve. Post-crush, in the mouse, myelin staining was localised close to the crush site, with strong lysosomal staining within both 'resident' and invading haematogenously derived macrophages. In the rat, myelin sheaths stained strongly throughout the nerve very soon after crush, but no macrophages were detected using these antisera. Paranodal myelin and some Schmidt-Lanterman incisures were the first regions of the sheath to show an increase in PLA2 staining post-crush, areas where the first ultrastructural changes occur in myelin after trauma, with staining of compact myelin closely following. Our findings support the idea that PLA2 may be involved in the early process of myelin breakdown seen in Wallerian degeneration.

Animals↗
PubMed1989

Improved colorimetric assay for detecting influenza B virus neutralizing antibody responses to vaccination and infection.

An automated neutralization test for influenza B virus is described in which antibody titers are determined according to the release of neutral red from infected or uninfected cells of the Madin-Darby canine kidney line. Endpoints are determined in a standard enzyme-linked immunosorbent assay reader. The test requires no expensive immunologic reagents and was used to evaluate responses to both vaccination and natural infection against influenza B virus. Overall responses to vaccination were comparable with those obtained by hemagglutination inhibition, using Tween-ether-split influenza B/Ann Arbor/1/86 virus as the antigen (the HI-TE test). The sensitivities of neutralization responses compared with those obtained by the HI-TE test for two vaccines were 88 and 89%; the specificities were lower at 61 and 60%, respectively. Responses to vaccination, measured by hemagglutination inhibition, were significantly higher with split virus compared with whole virus. However, seroconversion by both the HI-TE and neutralization tests was observed in 5 of 10 individuals from whom virus was detected by either culture of nasal or throat washings or the presence of antigen from immunofluorescence in cells from nasal washings.

Animals↗
PubMed1988

An improved membrane-filtration enzyme immunoassay for the rapid serological diagnosis of viral infections.

A one-step modification of the membrane-filtration enzyme immunoassay (MF EIA) (Barnett et al., J. Clin. Microbiol., 23:385-399, 1987), for estimation of virus-specific antibody is described. The modified MF EIA allowed serum, antigen and enzyme-conjugated anti-globulin to be incubated together in membrane-based 96-well plates to enable the formation of immune complexes in solution at 37 degrees C. The assay required only 45 min for completion and polyethylene glycol was shown to be an essential component in reaction mixtures for IgG assays to enhance immune complex formation. The modified MF EIA was as sensitive as the previous two-step method for monitoring responses to influenza vaccine, and control antigen backgrounds were significantly reduced. The one-step procedure was also shown to be suitable for the rapid serodiagnosis of naturally acquired influenza A and B infections. However, MF EIA detected cross-reactive H1N1 responses in 57.7% of naturally-acquired H3N2 infections, suggesting that responses to common internal antigens were being measured. Cross-reactive responses to influenza A viruses could not be detected in volunteers receiving subunit vaccines.

Antibodies, Viral↗
PubMed1987

Homotypic and heterotypic immunity of influenza A viruses induced by recombinants of the cold-adapted master strain A/Ann Arbor/6/60-ca.

The cold-adapted (ca) influenza A virus A/Ann Arbor/6/60-ca when administered intranasally to mice in two doses 3 weeks apart induces solid immunity to challenge 3 weeks later with heterotypic influenza A wild-type viruses (17). In the present study heterotypic immunity against viruses from different sub-types was shown to be relatively short-lived, having declined significantly 9 weeks after vaccination and being completely absent by 21 weeks. On the other hand, immunity against challenge viruses with surface antigens similar to the ca vaccinating virus or to other H 3 N 2 viruses remained high, even in the absence of detectable serum haemagglutination-inhibiting antibody. Both short- and long-term immunity induced by ca viruses was unaffected by earlier priming experiences with other wild-type or ca viruses. These results suggest that at least two mechanisms are involved in respiratory immunity to influenza viruses.

Animals↗
PubMed1987

Freeze-drying of respiratory syncytial viruses for transportation and storage.

The stabilities of eight strains of respiratory syncytial virus were compared after the strains were freeze-dried in the presence and absence of the stabilizer SPGA, which contains 218 mM sucrose, 7.1 mM dipotassium hydrogen phosphate, 3.76 mM potassium dihydrogen phosphate, 4.9 mM sodium glutamate, and 1% (wt/vol) bovine albumin. Strains freeze-dried in the presence of SPGA showed only small-to-negligible losses at 4 degrees C and losses of approximately 2.0 log10 infectious units at 25 degrees C when held for 45 weeks. Losses at 37 degrees C for one strain were approximately 10-fold greater when the strain was freeze-dried in the absence of SPGA. These results indicate that respiratory syncytial virus strains freeze-dried in the presence of a suitable stabilizer can be transported as unrefrigerated samples without undue losses in infectivity.

Excipients↗
PubMed1985

Immunization against influenza by the ocular route.

The immunogenicity of influenza A strain A/Northern Territory/60/68 for CSL mice when delivered by the ocular, nasal and subcutaneous routes was determined according to the median protective dose, PD50, i.e. the dose of infectious virus required to induce inhibition of multiplication of a standard intranasal challenge dose of 10(4.5) median tissue-culture-infectious doses (TCID50) of homologous virus three weeks after vaccination (PD50). For mice inoculated by the ocular route, an immunizing dose of 10(2.89) TCID50 per animal was required. For anaesthetized mice vaccinated intranasally and unanaesthetized mice vaccinated subcutaneously these figures are less than 10(2.00) and greater than 10(6.00) TCID50 per animal, respectively. The lower immunogenicity of virus delivered by the ocular route compared with the intranasal route can be correlated with a lowered capacity of ocularly administered virus to replicate in the murine respiratory tract. The immunogenicity of A/Ann Arbor/6/60-ca administered in two identical doses, was also determined for (a) the intraocular route, (b) the intranasal route with anaesthetized animals and (c) the intranasal route with unanaesthetized animals, using the parental A/Ann Arbor/6/60 as the challenge virus. Two doses were required because ca viruses have been shown to be poor immunogens in the same animal model. The PD50 for the ocular route was 10(2.83) TCID50 per animal compared with 10(2.71) for the intranasal route using unanaesthetized animals and 10(1.36) for the intranasal route using anaesthetized animals. Administration of living attenuated vaccine viruses by the ocular route is thus an effective means of inducing immunity to influenza viruses in the respiratory tract of mice.

Animals↗
PubMed1985

Evaluation of chicken kidney and chicken embryo kidney cultures for the large-scale growth of attenuated influenza virus master strain A/Ann/Arbor/6/60-ca.

Primary chicken kidney (CK) and chicken embryo kidney (CEK) cells were evaluated as possible substrates for growth of the cold-adapted attenuated influenza vaccine master strain A/Ann Arbor/6/60 (A/AA/6/60-ca). Yields of 10(6)-10(7) TCID50 per ml of culture fluid were obtained in either cell type. Yields from the human diploid strain MRC-5 were approximately 100-fold less. More reproducible cultures were obtained from CEK cells, using an overnight trypsinization step at 4 degrees C, than from CK cells. Comparable yields per embryo were obtained from CEK cells grown in roller cultures to those grown on the surface of microcarriers. These yields were less than those obtained from the allantoic fluids of whole embryos. Frozen storage of CEK or CK cells, after primary trypsinization, dispersal from a cultured CK primary monolayer or culture on microcarriers, was unsuccessful. The cold-adapted phenotype of A/AA/6/60-ca was retained after growth in CEK cultures and no differences in immunogenicity were detectable in mice between CEK- and allantoic-grown virus. Allantoic-grown preparations of A/AA/6/60-ca contained a lower protein concentration per infectious unit than those grown in CEK.

Animals↗
PubMed1984

Relative immunogenicity of the cold-adapted influenza virus A/Ann Arbor/6/60 (A/AA/6/60-ca), recombinants of A/AA/6/60-ca, and parental strains with similar surface antigens.

The immunogenicity of several cold-adapted (ca) viruses was compared in CSL mice with that of wild-type parental viruses with similar surface antigens, according to the vaccinating dose required to clear a challenge consisting of 10(4.5) 50% tissue culture infective doses of the wild-type virus. All ca viruses were less immunogenic than their wild-type parental strains by a factor of 10(1.3) to 10(3.4), probably due to the restricted capacity of ca viruses to replicate in the respiratory tracts of mice. However, their immunogenicity was considerably enhanced when two quite small doses were administered 3 weeks apart. The immunogenicity of ca viruses when administered in two doses and wild-type viruses when administered as a single dose varied according to their surface antigens. It was highest for viruses with the H2N2 A/Ann Arbor/6/60 and H3N2 A/Queensland/6/72 surface antigens and lowest for those with H1N1 A/HK/123/77 surface antigens. When two doses consisting of 10(5.0) 50% tissue culture infective doses of A/Ann Arbor/6/60-ca were administered at an interval of 3 weeks, solid immunity was induced against the wild-type A/Ann Arbor/6/60 parental virus, two heterologous H3N2 strains, and an H1N1 strain.

Animals↗
PubMed1983

Immunization against influenza by the ocular route. Brief report.

The immunogenicity of influenza A strain A/Northern Territory/60/68 for mice when delivered by the ocular, nasal and sub-cutaneous routes was determined according to the dose of infectious virus required to induce inhibition of multiplication of a standard intransal challenge dose in 50 per cent of animals per group 3 weeks after vaccination. For mice inoculated by the ocular route, an immunizing dose of 10(2.89) TCID50 per animal was required. For anesthetised mice vaccinated intranasally and unanaesthetised mice vaccinated sub-cutaneously these figures are less than 10(2.0) and greater than 10(6.0) TCID50 per animal, respectively. The lower immunogenicity of virus delivered by the ocular route compared with the intranasal route can be correlated with a lowered capacity of ocularly administered virus to replicate in the murine respiratory tract.

Animals↗
PubMedDate not supplied

Expression of cytochrome P450 aldosterone synthase and 11 beta-hydroxylase mRNA during adrenal regeneration.

In situ hybridization histochemistry was used to monitor the expression of cytochrome P450 aldosterone synthase (P450aldo) and cytochrome P450 11 beta-hydroxylase (P45011 beta) mRNA in regenerating rat adrenals. Comparisons were made between regenerating adrenals from unilateral enucleated/unilateral adrenalectomized (ULE/ULA) and bilateral enucleated (BLE) rats. During the first week after enucleation, P45011 beta mRNA was expressed in all adrenals reflecting the presence of fasciculata cells; however, P450aldo mRNA was detected only in adrenals from ULE/ULA rats suggesting that the glomerulosa cell phenotype was absent after BLE. These findings suggest that the expression of glomerulosa cells during the early period of regeneration is influenced by the presence of a second regenerating adrenal.

Adrenal Glands↗