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Biomedical subjects

M J Perry

Publications and source records attributed to M J Perry.

At least 73 records · Page 4Linked to original sources
PubMed1996

Alteration to the levels of galanin in uninjured contralateral rat saphenous nerves after unilateral saphenous nerve section.

Previous work in this laboratory has demonstrated that unilateral injury to the rat saphenous nerve decreases levels of substance P in the uninjured contralateral saphenous nerve during the subsequent regenerative period. Furthermore this contralateral nerve also has a decreased ability to elicit a neurogenic inflammatory response. In this present study the levels of galanin were investigated under similar experimental conditions. Levels of this peptide were found to be significantly decreased in the uninjured contralateral nerve. No significant changes in the total protein level of these nerves was found as compared to the control uninjured animals. The implications of this, in the context of the other contralateral changes found after peripheral nerve injury, are discussed.

Animals↗
PubMed1996

Use of protease inhibitors increases the amounts of substance P extracted from small specimens of nerve tissue.

When using radioimmunoassay to measure the levels of peptides from small pieces of nerve tissue it is crucial to maximize the amount of peptides extracted. Here we report on the value of including protease inhibitors in the extraction buffer when extracting substance P (SP) from short lengths of rat saphenous nerve tissue. Nerve segments were removed from terminally anesthetized 13-week-old rats and directly added to acid buffer (including EDTA) either with or without 1 mM 4-(2-amino-ethyl)-benzesulfonyl fluoride-HCl, 2 micrograms/ml aprotinin, 100 microM leupeptin, 1 microgram/ml cystatin, and 1 mM benzamidine. These "direct" samples were then boiled for 10 min. With additional groups of pieces of saphenous nerve tissue the effects of leaving the samples for 10 min in both buffers at room temperature either intact ("delayed") or after mincing the tissue ("minced") were investigated. Addition of protease inhibitors increased the amount of SP extracted in both direct and delayed procedures, although the increase was only significant for the delayed situation (P < or = 0.05). "Delay" in the absence of protease inhibitors resulted in a significantly decreased amount of SP being extracted compared to the direct and minced situations (P < or = 0.05). We recommend use of protease inhibitors be included as part of the standard procedure for extracting neuropeptides from small specimens of nerve tissue for radioimmunoassay.

Animals↗
PubMed1996

Osteolytic properties of the synovial-like tissue from aseptically failed joint prostheses.

Relationships were found between the bone-resorbing ability of conditioned media (CMs) from culture of peri-prosthetic tissues and their levels of bone-remodelling agents. Bone-resorbing activity was measured by 45Ca release from pre-labelled mouse calvaria and 23 of 40 CMs exhibited bone-resorbing activity. Cytokine and prostanoid levels in the CMs were measured by immunoassay, and the levels of interleukin (IL)-1 beta, IL-6, tumour necrosis factor alpha (TNF alpha) and prostaglandin E2 (PGE2) correlated with each other, except for the latter two. Significantly higher levels of IL-6 were present in those CMs with bone-resorbing activity than in those without, and a similar pattern was observed for PGE2 and IL-1 beta. However, some CMs with high levels of IL-1 beta, IL-6, TNF alpha and PGE2 failed to induce resorption, whereas a few CMs with low levels of these agents induced resorption. Moreover, neither dialysis of CMs nor addition of neutralizing antisera to IL-1 alpha and IL-1 beta to CMs, either alone or in combination, reduced the bone-resorbing activity of the CMs. It is considered that these agents may act synergistically to mediate osteolysis around failed joint implants, but that other unidentified bone-resorbing agent(s) must be involved.

Adult↗
PubMed1996

HIV risk behaviors among women living in low-income, inner-city housing developments.

OBJECTIVES: This study describes the prevalence and predictors of human immunodeficiency virus (HIV) risk behaviors among women living in low-income, inner-city housing developments. METHODS: Anonymous questionnaires were administered to 671 women living in 10 inner-city, low-income housing developments in five US cities to determine their levels of HIV risk behavior and predictors of HIV risk practices. RESULTS: Approximately one third of women were at high risk for HIV because of the risk behavior of their sexual partners. HIV risk was highest among women who accurately perceived themselves to be at increased HIV risk, held strong beliefs about barriers to condom use, and reported weak behavioral intentions to reduce risk. Women at higher risk were also younger and reported higher rates of alcohol and substance use. CONCLUSIONS: HIV prevention efforts are needed for inner-city women. Interventions should focus on overcoming women's barriers to condom use, strengthening their intentions to change behaviors, and managing the risk related to their use of substances.

Adolescent↗
PubMed1995

In vitro fracture fixation: adhesive systems compared with a conventional technique.

To find out whether adhesive techniques could have a role in bone fixation in selected cases an in vitro comparison between the current 'Champy' miniplate system and bonded stainless steel was undertaken using cyanoacrylate or dental composite cement. 33 bovine ribs were sectioned to simulate fracture separation, divided randomly into three groups, and immobilised by one of the three treatments. Distraction across the 'fracture' was produced using a universal testing apparatus, and forces at failure were recorded in Newtons (N). Image analysis enabled the contact area of the adhesive to be determined in mm2, so the bond strength in N/mm2 was derived. The Champy system failed at a significantly greater force (N) than the adhesives (p = 0.000). There was no significant difference in bond strength between either of the adhesive systems tested.

Analysis of Variance↗
PubMed1995

Transglutaminase C in cerebellar granule neurons: regulation and localization of substrate cross-linking.

Covalent cross-linking of cell surface proteins by the calcium-dependent enzyme transglutaminase C may be implicated in cell-cell interactions and growth regulation. We demonstrate the presence of the enzyme in rat cerebellar cortex during postnatal development. Transglutaminase C was induced in cerebellar granule neurons in culture by retinoic acid, dibutyryl- and 8-bromo-cyclic AMP analogues and by cultivation on a biomatrix substratum. Cyclic AMP analogues stimulated transglutaminase activity in protein synthesis-dependent and -independent phases. The enzyme was distributed at focal adhesion sites on the axon. By calcium-dependent covalent incorporation of the primary amine acceptor substrate, 5-(biotinamido)pentylamine, an increase in the Ca(2+)-dependent cross-linking of at least 11 substrate proteins in the presence of retinoic acid and dibutyryl-cyclic AMP was detected. Of these substrates, a subset was labelled on the surface of living granule neurons. A low-molecular-weight substrate, p18, was tentatively identified as the retinoic acid-inducible neurite-promoting factor, midkine. Transglutaminase-mediated amine incorporation, midkine and isopeptide cross-links were co-localized to axonal adhesion sites. The results provide evidence of transglutaminase C-catalysed protein cross-linking activity in cerebellar granule neurons and its possible implication in cell-substratum interactions.

Amines↗
PubMed1995

Factors predicting continued high-risk behavior among gay men in small cities: psychological, behavioral, and demographic characteristics related to unsafe sex.

Nearly 6,000 men entering gay bars in 16 small American cities were anonymously surveyed to assess their sexual behavior and to determine predictors of risky sexual practices. Excluding individuals in long-term exclusive relationships, 27% of the men reported engaging in unprotected anal intercourse in the past 2 months. Factors strongly predictive of risk included having a large number of different male partners, estimating oneself to be at greater risk, having weak intentions to use condoms at next intercourse, believing that safer sex is not an expected norm within one's peer reference group, being of younger age, and having less education. These findings indicate that HIV prevention efforts are urgently needed for gay men in smaller cities, with efforts particularly focused on young and less educated men sexually active with multiple partners. Prevention should focus on strengthening intentions to change behavior and on changing social norms to foster safer sex.

Acquired Immunodeficiency Syndrome↗
PubMed1995

HIV antibody testing of gay men in smaller US cities.

The incidence of new AIDS diagnoses among gay males indicates that risk reduction in smaller communities may be lagging behind that reported in larger cities. Contradictory evidence exists, largely from urban areas, concerning the utility of HIV testing as a means of promoting behavioural change. This study examined the relationship between HIV antibody testing and subsequent high-risk sexual behaviours among gay men in cities of 180,000 or fewer inhabitants. In February and March of 1992, male gay bar patrons in sixteen small US cities were administered an anonymous questionnaire concerning recent sexual behaviour and HIV testing history. Of the 1820 respondents, 28.1% had recently engaged in unprotected anal intercourse and 60.7% had been tested for HIV antibodies. Those who had been tested were more sexually active and reported more protected and safer sexual activities. Analyses at the individual and city levels converged to demonstrate that communities as well as individuals evidence increased self-protection in association with HIV antibody testing.

Adult↗
PubMed1995

Analysis of cell types and mediator production from tissues around loosening joint implants.

Quantitative immunophenotypic analysis of cell types present in peri-prosthetic tissue [pseudosynovial membrane (PSM)] from aseptically loose joint implants revealed considerable heterogeneity between tissues from different individuals. The monocyte/macrophage was the commonest leucocyte type; however, its proportion varied widely. T cells normally accounted for approximately 5% of cells, but in a few cases formed > 20% of cells. In all cases, there was a high ratio of CD4 to CD8 cells. PSM leucocytes were activated in most PSMs as judged by surface expression of CD23, CD25 and CD71. Analysis of the proportions of cell types in PSM, OA synovium and RA synovium revealed similarities between the different tissue types. The levels of IL-1, IL-6 and prostaglandin E produced by the PSM were correlated, but only IL-1 and IL-6 levels correlated with markers of the monocyte/macrophage lineage. This result suggests that prostaglandin E is produced in vivo by many PSM cell types.

Adult↗
PubMed1995

Differences in HIV risk characteristics between bisexual and exclusively gay men.

Research investigating HIV-risk sexual behaviors of men who have sex with men usually combines gay and bisexual men, treating them as a single, homogeneous group. However, gay and bisexual men may differ in their HIV risk behavior and in psychological characteristics indicative of risk. Exclusively gay (N = 1,180) and bisexual men (N = 136) completed anonymous surveys at gay bars. The surveys assessed demographic, psychological, and behavioral data related to sexual behavior and HIV risk. Relative to exclusively gay men, bisexual men had lower intentions to use condoms in their next intercourse occasion, reported a greater frequency of oral sex with men and more oral-sex partners, knew fewer people who were HIV positive, and perceived weaker peer norms favoring safer sex and risk avoidance. One-third of bisexual men reported engaging in unprotected anal intercourse, and 17% of bisexual men had multiple unprotected anal sex partners in the past two months. Interventions tailored to the needs of bisexual men are urgently needed and should focus on increasing intentions to use condoms, increasing HIV-risk sensitization, and fostering norms favoring safer sex and risk avoidance.

Adult↗
PubMed1994

High risk sexual behavior and alcohol consumption among bar-going gay men.

OBJECTIVES: To determine whether alcohol use prior to sexual behavior influenced the occurrence of unprotected anal intercourse among bar-going gay men. METHODS: Anonymous AIDS behavioral risk surveys were administered to men entering gay bars in 16 cities on three nights in February 1993 in six states in the United States. RESULTS: Of the 1519 men who completed the survey, 85% were current alcohol drinkers. Men who had unprotected anal intercourse after consuming alcohol drank more and reported more incidents of unprotected anal intercourse than men who had unprotected anal intercourse but not after drinking. Overall, unprotected anal intercourse occurred less frequently after alcohol consumption than without prior consumption. CONCLUSIONS: This study found that heavy alcohol use and frequent high-risk sexual behavior occurred among the same individuals. However, we found no evidence for a causal link between alcohol use and unprotected sexual behavior in this sample of bar-going gay men.

Adult↗
PubMed1994

The Southeast Florida AIDS Information Network: a community outreach, specialized information system.

In the years ahead, end-user instruction will expand from the current models of curriculum- and institution-based programs for teaching MEDLINE to include outreach programs to unaffiliated users for teaching specialized database searching. The Southeast Florida AIDS Information Network (SEFAIN), a community-based information system targeting health care providers in a tri-county area, is an example of this new model. The components of SEFAIN and the results of the outreach and educational programs are presented. The advantages of these programs to both providers and librarians are highlighted. Comparisons are drawn between end users who take specialized information courses and those who take MEDLINE courses or no courses. These data will assist librarians in the justification and development of specialized information systems.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Use of diagnosis-related groups by non-Medicare payers.

Medicare's prospective payment system (PPS) for hospital cases is based on diagnosis-related groups (DRGs). A wide variety of other third-party payers for hospital care have adapted elements of this system for their own use. The extent of DRG use varies considerably both by type of payer and by geographical area. Users include: 21 State Medicaid programs, 3 workers' compensation systems, the Civilian Health and Medical Program of the Uniformed Services (CHAMPUS), more than one-half of the Blue Cross and Blue Shield Association (BCBSA) member plans, several self-insured employers, and a few employer coalitions. We describe how each of these payers use DRGs. No single approach is dominant. Some payers negotiate specific prices for so many combinations of DRG and hospital that the paradigm that payment equals rate times weight does not apply. What has emerged appears to be a very flexible payment system in which the only constant is the use of DRGs as a measure of output.

Data Collection↗
PubMed1993

Neurofilament in feline primary afferent neurones: a quantitative immunocytochemical study.

Two populations of cat L4 dorsal root ganglion (DRG) neurones were apparent from their Nissl staining with Toluidine blue. One had neurones of all sizes and the other had predominantly small neurones. The size distribution of neuronal profiles in the two populations overlapped and both were approximately normal. They corresponded to the light (L) and small dark (SD) cell populations previously described in rat DRGs. These neurones were examined with four antibodies to neurofilament: RT97, NFH, 155 and anti-68kD. RT97 is specific for the phosphorylated form of the 200 kDa subunit; NFH recognises both phosphorylated and non-phosphorylated forms of this subunit; 155 and anti-68 kDa recognise the 155 kDa and 68 kDa subunits respectively. The clearest differential labelling was seen with NFH and RT97 and this labelling was compared with cell size. High intensity NFH labelling was in a population of neuronal profiles of all sizes and low intensity labelling in a population of predominantly small neuronal profiles. These populations corresponded respectively to the L and SD populations seen with toluidine blue staining. In the rat, these populations can be demonstrated by both NFH and RT97. In contrast in the cat, high intensity RT97 labelling was seen in only 75% of the L neuronal profiles defined with NFH and was also seen in some SD neuronal profiles defined with NFH. It is thus proposed that L and SD cell types are present in the cat DRG and can be demonstrated using the anti-neurofilament marker, NFH.

Animals↗
PubMed1993

Neurofilaments in rat and cat spinal cord; a comparative immunocytochemical study of phosphorylated and non-phosphorylated subunits.

Neurofilament immunoreactivity was examined in spinal cords of rats and cats with antibodies to all three subunits (68 kD, 155 kD and 200 kD) and to different phosphorylation states of 200 kD. NFHP-, an antibody against non-phosphorylated 200 kD, labelled all rat neuronal perikarya but failed to label cat neurofilaments. In both species, the perikarya and processes of motoneurones were immunoreactive for all three subunits but most dorsal horn neuronal perikarya were not immunoreactive for 68 kD and 155 kD. Motoneuronal perikarya and proximal processes showed filamentous labelling for 68 kD but not for 155 kD in the rat, while in neither species did these show labelling with RT97, an antibody against a highly phosphorylated form of 200 kD; immunoreactivity for 200 kD was present in both filamentous (probably partially phosphorylated) and non-filamentous (non-phosphorylated) forms, but in dorsal horn neurones only the latter was present. Interpretations consistent with this data are: in rat and possibly also cat, motoneuronal neurofilaments consist of a 68 kD backbone with partially phosphorylated 200 kD sidearms, with both 155 kD and 200 kD (nonphosphorylated) subunits in a non-filamentous form; this neurofilament becomes more highly phosphorylated along the proximal processes. The dorsal horn neurones probably contain 200 kD in a non-filamentous form but may lack the other subunits.

Animals↗
PubMed1993

Assays of cyclic nucleotides. A review of current techniques.

Cyclic nucleotides are recognized as important second messenger molecules, and many assay formats exist for their quantification. This article critically reviews these different approaches. For measurement of cAMP or cGMP in biological fluids or tissue extracts, immunoassay is effective. For other purposes, such as measurement of cyclic nucleotide phosphodiesterase activity, methods that separate nucleotides from their cyclic counterparts are best, and offer a variety of means of detection.

Chromatography↗
PubMed1993

Primary sensory neurones: neurofilament, neuropeptides, and conduction velocity.

This paper reviews and provides new data on the relationship of the peptide content in rat dorsal root ganglion (DRG) neurons to a) the neurofilament content of the soma and b) the conduction velocities of the fibres. The latter involved intracellular recordings made in vitro followed by dye injection and immunocytochemistry. Because neurofilament-poor DRG neurones have C-fibres, and A-fibre neurones are neurofilament rich, the soma neurofilament content of peptide containing neurones allowed predictions to be made about their conduction velocity ranges. Substance P-like immunoreactive (SP-LI) neurones were mostly small, neurofilament poor, but a few (15%) were neurofilament rich. From conduction velocity measurements, about half the C-fibre neurones studied and 10% of A delta-neurones but no A alpha/beta-neurones showed SP-LI. CGRP-LI neurones were also mainly neurofilament poor neurones, but 32% were neurofilament rich, including small, medium, and large neurones. Fibres of CGRP-LI neurones conducted in the C, A delta or A alpha/beta ranges. Neurones with somatostatin-LI (SOM-LI) were all neurofilament poor; preliminary data is consistent with SOM-LI neurones having C-fibres.

Animals↗