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Biomedical subjects

A Bennett

Publications and source records attributed to A Bennett.

At least 55 records · Page 3Linked to original sources
PubMed1997

Comparison of SSCP analysis and CFLP analysis for mutation detection in the human iduronate 2-sulfatase gene.

Scanning methodologies are used for the identification of DNA fragments that differ from the normal nucleotide sequence. Fragments that produce abnormal band patterns are sequenced for characterization of the exact mutation. Factors considered in choosing a scanning methodology include reproducibility, sensitivity, and time. In the present study, we compared single-stranded conformational polymorphism (SSCP) and Cleavase fragment length polymorphism (CFLP) methodologies for mutation scanning of exon VIII in the iduronate 2-sulfatase (IDS) gene. Mutations of the IDS gene result in an X-linked lysosomal storage disease, Hunter syndrome. These six known mutations analyzed by the two methods included a one base pair deletion, a one base pair insertion, and four point mutations. SSCP analysis detected all of the mutations and CFLP analysis detected three of the six mutations. We concluded that SSCP analysis was preferable to CFLP analysis for scanning exon VIII in the IDS gene for mutations.

Base Sequence↗
PubMed1997

Chronic fatigue syndrome/myalgic encephalomyelitis as a twentieth-century disease: analytic challenges.

The challenges of chronic fatigue syndrome (often called myalgic encephalomyelitis, especially in the UK) (CFS/ME) to analytical and medical approaches are connected with our inability to understand its distressing somatic symptoms in terms of a single identifiable and understandable disease entity. The evidence for the roles of viral aetiologies remains inconclusive, as does our understanding of the involvement of the immune system. The history and social context of CFS/ME, and its relation to neurasthenia and psychasthenia are sketched. A symbolic attitude to the condition may need to be rooted in an awareness of psychoid levels of operation, and the expression and spread of CFS/ME may sometimes be aided by the ravages of projective identification. Psychic denial, sometimes violent, in sufferers (especially children and adolescents) and their families may be important in the aetiology of CFS/ME. We draw out common threads from psychodynamic work with five cases, four showing some symptomatic improvement, analytic discussions of three cases being presented elsewhere in this issue of JAP.

Adolescent↗
PubMed1997

A view of the violence contained in chronic fatigue syndrome.

In this paper I ask whether there might be any one particular psychopathology likely to be linked specifically with the physical illness known as chronic fatigue syndrome (CFS) or myalgic encephalomyelitis (ME), and whether CFS/ME aids and abets and "fits' an original mental state. I think the question cannot yet be answered. However it is my hypothesis that in some personality structures the onset of CFS/ ME following a physical illness exacerbates negativity and is an aspect of ordinary depression where there is a lowering of energy levels and a loss of zest for life, or it may reveal the pathological aspect of unresolved rage. Depending on the degree of pathological disturbance, working with and through the rage may or may not result in a resolution of the symptoms of ME. In this paper I consider some of the problems in the transference and countertransference relationship, which make it extremely difficult to separate out reality from phantasy. There is then the further problem of the denial of the psyche by the patient as part of the violence inherent in the illness. One case is presented, an example of ME in a borderline male patient in whom resolution could not be achieved.

Adult↗
PubMed1997

The Mattis Dementia Rating Scale in nursing home octogenarians and nonagenarians: effects of age and education.

Despite their increasing representation in the population, little is known about the neuropsychological test performance of the oldest old, particularly those who live in residential settings. Limited published data and clinical experience suggest that this group is more likely to perform in the impaired range on standardized tests when cut-offs developed with younger groups are used. We examined the Dementia Rating Scale (DRS) performance of 82 nondemented nursing home residents, aged 80 to 99, with a mean education level of 11 years. Using published norms and cutoffs, a large percentage of this sample performed in the impaired range, particularly on the initiation and conceptualization subtests and on the total score. Education, but not age, was significantly related to performance in this sample. Percentages of patients misclassified were substantial in all groups, but were higher in those with less than 13 years of education. Using a lower total-score cutoff of 110 reduced the percentage of misclassifications markedly. We recommend the development and use of revised cutoff scores for the evaluation of very elderly nursing home residents.

Age Factors↗
PubMed1997

Promoting condom-only brothels through solidarity and support for brothel managers.

Brothel workers in Thailand are at high risk of HIV infection but they alone do not have adequate bargaining power to insist on condom use with all clients. Brothel managers, on the other hand, are a source of influence over both clients and their workers and can promote universal condom use in their establishments. To test whether brothel managers in Khon Kaen City would adopt and successfully implement a condom-only policy in their establishments, all 24 brothel managers in Khon Kaen City attended a meeting on the dangers of HIV and benefits of an all-condom policy. Ideas on how to implement the policy were discussed. Follow-up visits were made once a month to brothels to resupply condoms, provide reinforcement and to collect data. All brothel managers approved of the condom-only in principle and are now implementing the policy. Results of the evaluation of condom use and degree of solidarity in these 24 brothels are available for the AIDS prevention programme. However, a condom-only policy in brothels can only succeed if managers and brothel workers show solidarity in rejecting all non-condom using clients. Laws to promote condom use may not be needed if brothels are given the opportunity to implement a condom-only policy using their own resourcefulness and determination.

Adult↗
PubMed1997

HIV risk behavioral surveillance in Bangkok, Thailand: sexual behavior trends among eight population groups.

OBJECTIVE: To assess trends in HIV risk behaviors over a 3-year period in eight population groups in Bangkok, Thailand. DESIGN AND SUBJECTS: Using a repeated cross-sectional survey design with a structured questionnaire, we collected five sets of self-reported sexual behavior data related to HIV risk from the following subject groups at the same sampling sites during 1993-1996: direct and indirect female sex workers, male attenders of sexually transmitted disease (STD) clinics, female attenders of antenatal care clinics, male and female vocational students, and male and female factory workers. RESULTS: Reported patronage of commercial sex by the three male groups declined by an overall average of 48% over the 3-year period. Other non-regular sexual partnerships declined among male STD clinic attenders and vocational students. Condom use during most recent sexual intercourse between sex workers and clients peaked at high levels (>90%) in the early data waves, while among indirect sex workers and their clients, consistent condom usage increased from 56% to 89%. Low condom use persisted among sex workers and their non-paying sex partners. Single women reported low levels of sexual activity and condom use with no signs of an increase. Similarly, married women from antenatal clinics reported low condom use with their husbands, with no change throughout the period of the study. CONCLUSIONS: HIV risk behavioral surveillance is a useful way of determining whether behavior change has occurred in specific population groups. The results here confirm and add to a growing set of evidence of risk behavior reduction in Thailand. The behavioral changes did not occur uniformly but varied depending on the sexual dyad and the population group under study. Behavioral surveillance should be promoted and its methodologies strengthened in attempts to understand the local dynamics of HIV epidemics.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Men with sexually transmitted diseases in Bangkok: where do they go for treatment and why?

OBJECTIVES: To describe and identify predictors of health-care seeking behavior among men with sexually transmitted diseases (STDs) in Bangkok, Thailand. DESIGN: Cross-sectional survey. METHODS: Men presenting with STDs were recruited from government clinics (n = 101), private clinics (n = 50) and pharmacies (n = 62). They completed interviewer-administered questionnaires on risk behavior, patterns of treatment-seeking for current and past STDs and attitudes toward health care. RESULTS: Two-thirds of all subjects had had a previous STD. Approximately one-half believed a partner other than a sex worker was the source of their current infection. Of the sample, 39% of men seen initially at drugstores, 29% at private clinics and 19% at government clinics sought subsequent treatment; failure to respond to therapy was the primary reason for seeking additional care. Men attending drugstores were likely to be younger, have less education and income, and to practice riskier sexual behavior. Patients at drugstores and general private clinics received the least amount of counseling or STD testing, while those attending specialized private STD clinics received the most comprehensive services. Attitudes towards government clinics were uniformly positive regardless of the site of enrollment; conversely, about 50% of clients at drugstores felt that the advice and treatment they received were inadequate. Convenience, affordability and lack of embarrassment were associated with choice of treatment site. CONCLUSIONS: STD/HIV control in Thailand must focus on improved treatment and counseling at the point of first encounter in the health-care system, particularly in the private sector. Men may be dissuaded from attending government clinics because of lack of convenience. Syndromic case management, incorporation of STD care at other public clinics and the recognition that more men practice unsafe sex with partners other than sex workers could improve STD control.

Adolescent↗
PubMed1996

Effects of D-myo-Inositol-1,2,6-triphosphate on eicosanoid formation in burned skin.

D-myo-Inositol-1,2,6-triphosphate (IP3) has been shown to reduce edema and progressive ischemia following experimental skin burns. The mechanism(s) are not identified but could be related to antiinflammatory effects of the agent. In the present ex vivo study we compared the effects of IP3 with those of saline and indomethacin on eicosanoid formation by normal and burned rat skin. In burned skin IP 3 treatment reduced the release of thromboxane B2 (TXB2) (P < 0.01) and leukotriene B4 (LTB 4) (P < 0.05) but there was only a weak trend for less prostaglandin E (PGE) compared to burned control animals receiving saline. Indomethacin reduced the release of TXB2 (P < 0.01), and PGE (P < 0.001), but not LTB 4 from burned skin compared to skin from saline-treated burned animals. In non-burned skin IP 3 increased the release of PGE (P < 0.01) and LTB 4 (P < 0.01), but did not significantly influence TXB2 accumulation in the incubation fluid compared to the saline-treated group. Indomethacin reduced the release of TXB2 (P < 0.001) and PGE (P < 0.001), but increased LTB 4 (P < 0.001) in normal skin compared to the saline-treated group. In conclusion, IP 3 inhibited the release of TXB2 and LTB 4 from burned skin ex vivo, but increased PGE and LTB 4 release from normal skin. These results suggest that the mode of action of IP 3 differs from that of nonsteroidal antiinflammatory drugs. The effects of IP 3 on the arachidonic acid cascade also seem to differ in burned versus normal skin.

Animals↗
PubMed1996

Safe biotechnology. 7. Classification of microorganisms on the basis of hazard. Working Party "Safety in Biotechnology" of the European Federation Biotechnology.

The current systems for classifying human pathogens on the basis of hazard are well developed and their basic criteria are in general agreement one with another. Of more importance, the safety practices based on these classifications have generally been successful. They have enabled extensive research activities, medical practice and industrial production to be conducted on an ever-increasing scale, involving dangerous microorganisms (e.g. in vaccine production and treatment of infected patients) with a very low incidence of adverse effects on the workers involved and the general public. Although the EU has adopted a harmonised list of agents in groups 1-4 there is as yet no complete agreement among member states and individual microbiologists. The purpose of this paper is to present a historical survey and to discuss the current processes for identifying and classifying the hazards posed by the use of microorganisms in research and technology. This is essential in the design of appropriate methods of counteracting potential risks.

Bacteria↗
PubMed1996

High molecular weight phospholipase A2 and fatty acids in human colon tumours and associated normal tissue.

Human colon tumours usually form more prostaglandins (PGs) than associated normal tissues, but the mechanism(s) are not fully understood. We analysed fatty acid compositions, in particular arachidonate, and measured the amount and the activity of high molecular weight cytoplasmic phospholipase A2 (cPLA2) of these tissues. Total lipids extracted from homogenised surgical specimens were transesterified and fatty acids were analysed by gas chromatography. cPLA2 was separated by SDS-PAGE, Western-blotted, immunoblotted using a specific antibody to cPLA2 and semiquantified following enhanced chemiluminescence using a scanning densitometer. cPLA2 biological activity was also assayed using 1-stearoyl, 2-[1-14C]-arachidonyl, L-3-phosphatidylcholine. Compared with normal mucosa/submucosa, there was more total arachidonate in tumours (P < 0.01), and increased levels of cPLA2 occurred in 6 of 17 tumours. In conclusion, the higher amounts of tumour total arachidonate and the sometimes higher levels of cPLA2, might help to explain why some human colon tumours form increased amounts of PGs.

Adult↗
PubMed1996

Comparison of technetium-99m-HMPAO and technetium-99m-ECD cerebral SPECT images in Alzheimer's disease.

UNLABELLED: SPECT has shown increasing promise as a diagnostic tool in Alzheimer's disease (AD). Recently, a new SPECT brain perfusion agent, 99mTc-ethyl cysteinate dimer (99mTc-ECD) has emerged with purported advantages in image quality over the established tracer, 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO). This research aimed to compare cerebral images for 99mTc-HMPAO and 99mTc-ECD in discriminating patients with AD from control subjects. METHODS: Twenty-four AD patients (mean age +/- s.d. = 68.9 +/- 8.2 yr) and 13 healthy subjects (68.4 +/- 8.0 yr) were scanned sequentially with 20 mCi of each tracer using the CERASPECT system within 1 mo. Scanning began on average 11.5 +/- 2.8 min after 99mTc-HMPAO injection and 41.8 +/- 10.1 min after 99mTc-ECD. A ratio, R, was derived of count densities in "typically affected" brain structures (parietal and temporal association cortices) to "unaffected" structures (cerebellum, basal ganglia, thalamus, occipital cortex, and sensorimotor cortex). RESULTS: Analysis of variance revealed significant interaction between diagnostic group and radiopharmaceutical (F = 4.71; df = 1.35; p = 0.04), with 99mTc-ECD demonstrating better separation of R values between AD patients and control subjects than 99mTc-HMPAO. Receiver operating characteristic (ROC) analysis, revealed no significant difference in the ability of the two tracers to correctly classify AD patients and control subjects. Both tracers showed high diagnostic accuracy (99mTc-ECD: sensitivity = 100%, specificity = 92%; 99mTc-HMPAO: sensitivity = 100%, specificity = 85%). CONCLUSION: Technetium-99m-ECD shows greater contrast than 99mTc-HMPAO between affected and unaffected brain structures in AD when patients are compared to age-matched control subjects. Both tracers perform equally well in correctly classifying patients and control subjects.

Aged↗
PubMed1995

The effect of folate on the methotrexate/indomethacin interaction in a murine cancer cell line.

1. The effect of folate on the interaction between methotrexate (a folate analogue) and indomethacin has been examined in murine NC carcinoma cells. 2. Conditioning of NC cells to a physiological (20 nM) folate concentration after culture in a high folate concentration increased the response to methotrexate. The sensitivity of these conditioned cells to methotrexate related inversely to the folate concentration. 3. At 20 nM and 2 microM folate, indomethacin 1 micrograms ml-1 potentiated the cytotoxicity of methotrexate 4 and 8 ng ml-1 (both P < 0.03). 4. When NC cells were incubated with [3H]-methotrexate at 20 nM and 2 microM folate, there was a trend for increased tritium accumulation with indomethacin 0.36 micrograms ml-1 (1 microM; P < 0.01). 5. We conclude that the folate concentration can affect the sensitivity of NC cells to methotrexate, although the degree of potentiation of cytotoxicity by indomethacin remains similar.

Animals↗
PubMed1995

Interaction between methotrexate and indomethacin on a human normal haemopoietic cell line.

1. The interaction between methotrexate and indomethacin has been examined, at a physiological folate concentration (20 nM), on a human normal lymphoblast-like cell line (RPMI 1788) in vitro. 2. Indomethacin (1 microgram ml-1) increased the reduction of lymphoblast growth caused by methotrexate (10-80 ng ml-1). 3. Indomethacin (0.1 and 1 microgram ml-1) potentiated the cytotoxicity of methotrexate (20 and 40 ng ml-1) after 4 days in culture. 4. Indomethacin (0.4 micrograms ml-1) reduced the accumulation of tritium in lymphoblasts incubated with [3H]-methotrexate after 30 min; therefore initial drug accumulation was not responsible for the potentiation seen after 4 days. 5. If indomethacin increases the killing of human cancer cells by methotrexate in vivo, with a smaller potentiation on lymphoblasts, this combination may be beneficial in treating human malignancy.

Adult↗
PubMed1995

The thermal acclimation of burst escape performance in fish: an integrated study of molecular and cellular physiology and organismal performance

Goldfish (Family Cyprinidae, Carassius auratus) and killifish (Family Cyprinodontidae, Fundulus heteroclitus) were acclimated to 10, 20 and 35 &deg;C for 4 weeks. The thermal acclimation of C-start (escape swimming) performance and the physiological properties of fast twitch muscle fibres that underlie it were investigated in these species at the molecular (myosin isoform expression), biochemical (myofibrillar ATPase activity), cellular (contractile kinetics) and organismal levels of organisation. Peptide maps were obtained for fast muscle myosin heavy chains, isolated from 10 &deg;C- and 35 &deg;C-acclimated fish. Different myosin heavy chain isoforms were expressed in response to a change in acclimation temperature in goldfish, but myosin heavy chain isoform expression was unaffected by acclimation temperature in killifish. Compared with fish acclimated to 35 &deg;C, acclimation to 10 &deg;C increased the activity of fast muscle myofibrillar ATPase assayed at 10 &deg;C fivefold in goldfish and only 50 % in killifish. Muscle twitch contraction time at 10 &deg;C decreased significantly in response to acclimation to 10 &deg;C in both species; however, the magnitude of this response was much greater in goldfish (100 %) than in killifish (30 % or less). In goldfish, these changes in the physiological properties of fast twitch fibres during 10 &deg;C acclimation resulted in a six- to eightfold increase in the speed and turning velocity of fish performing C-starts at 10 &deg;C. By comparison, the somewhat smaller acclimatory response of killifish fast muscle properties was accompanied by only a minor (50 % or less) adjustment in locomotor performance. Thermal acclimatory responses of fast muscle at the molecular, biochemical and cellular levels of organisation are clearly reflected in alterations in organismal escape performance.

Journal Article↗
PubMed1995

Activity of nimesulide on constitutive and inducible cyclooxygenases.

Prostaglandins are pro-inflammatory but are gastroprotective. The gastric mucosa synthesizes prostaglandins mainly via constitutive cyclooxygenase (COX-1), whereas leucocytes have inducible enzyme (COX-2). Nimesulide (CAS 51803-78-2) differentially inhibited prostanoid synthesis in these human tissues as well as with in vitro enzyme assays, and was less potent than indometacin (CAS 53-86-1) on COX-1. Fresh human gastric mucosa was cut finely, washed and pre-incubated (100 mg in 1 ml phosphate buffered saline pH 7.4) with or without nimesulide or indometacin (0.1-100 micrograms/ml; 0 degree C; 30 min). The fluid was replaced with fresh identical solution, incubated (37 degrees C; 30 min) and the solution assayed. Isolated leucocytes from human peripheral blood were incubated (1-1.5 x 10(6), 2 ml Krebs' solution) with or without nimesulide or indometacin (0.1-100 micrograms/ml; 37 degrees C; 1 h), stimulated with lipopolysaccharide (5 micrograms/ml), further incubated for 24 h at 37 degrees C and the medium assayed for the prostanoids PGE, TXB2, 6-keto-PGF1 alpha and the leukotriene LTB4 by radioimmunoassay (RIA). In vitro assays with COX-1 from ram seminal vesicles, or COX-2 from sheep placenta, were performed by pre-incubating the enzymes with vehicle alone (controls) or with drug for 5 min at 37 degrees C. Arachidonate (10 mumol/l) was added and further incubated for 2 min at 37 degrees C. Reactions were terminated and PGE determined by RIA. Both drugs caused concentration-related inhibitions of prostanoid accumulation in incubates of both tissues. Nimesulide reduced PGE accumulation more potently in incubates of stimulated leucocytes than of gastric mucosa. With gastric tissue, nimesulide was less potent than indometacin by approximately 6-22 fold (IC50 for PGE, TXB2, 6-keto-PGF1 alpha, respectively; 14.8 vs 2.5; 12.8 vs 1.0; 31.1 vs 1.4 mumol/l; p < 0.05 to 0.02). With the leucocytes, the concentrations of both drugs, particularly indometacin were not low enough to calculate the IC50. With the in vitro assay, nimesulide (0.01 to 100 mumol/l) did not inhibit PGE formation by COX-1 but caused a concentration-related inhibition of PGE formation by COX-2 (4-60%). These results are consistent with the effective analgesic/anti-inflammatory activity of nimesulide coupled with better gastric tolerance compared to indometacin.

Adult↗