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Biomedical subjects

F Jones

Publications and source records attributed to F Jones.

At least 19 recordsLinked to original sources
PubMed1992

Health effects of white-water canoeing.

There is little quantitative information on the relation between water quality and disease attack rates after recreational activities in fresh water. We conducted a prospective cohort study to measure the health effects of white-water and slalom canoeing in two channels with different degrees of microbial contamination. Site A, fed by a lowland river, showed high enterovirus concentrations (arithmetic mean 198 pfu per 10 litre and moderate faecal coliform concentrations (geometric mean 285/dl); at site B, from an upland impoundment, all samples were free of enteroviruses and the geometric mean faecal coliform concentration was 22/dl. Between 5 and 7 days after exposure canoeists using site A had significantly higher incidences of gastrointestinal and upper respiratory symptoms than canoeists using site B or non-exposed controls (spectators). Like seawater bathers, fresh-water canoeists can be made ill by sewage contamination. The hazard of fresh water may be best measured by counting of viruses rather than bacteria.

Adult↗
PubMed1992

Disease concordances amongst marital partners: not 'way of life' or mortality data artifact.

Mortality statistics for Great Britain (1979-80, 1982-3) for more than 500 occupations and 20 different causes of death were examined. The paper demonstrates that there is clear concordance of cause of death between men and married women which can be linked to the occupation of the male. Various possible explanations are considered including shared social class and way of life and the suggestion that the associations reported are the result of various forms of statistical bias inherent in Standardized Mortality Ratio statistics. It is proposed that this is consistent with a psychosocial hypothesis, although longitudinal empirical research would be required to establish this.

Adult↗
PubMed1992

An AIDS-related knowledge, attitudes, beliefs, and practices survey among schoolchildren in Barbados.

A knowledge, attitudes, beliefs, and practices (KABP) survey was performed among Barbadian secondary schoolchildren 11-16 years old in January 1990. The survey sought to assess the children's knowledge of AIDS and human immunodeficiency virus (HIV) transmission; their attitudes toward people with HIV/AIDS; their sexual practices; and changes needed in education programs seeking to reduce childhood HIV transmission. A pretested self-administered questionnaire was used. The survey sample was derived by selecting every eleventh student on the rosters of all the secondary schools in Barbados. All of the survey respondents completed the questionnaire on the same day, having been assembled examination-style for that purpose. The results showed high levels of correct knowledge about the principal routes of HIV transmission. However, a considerable proportion of the respondents harbored incorrect beliefs regarding mosquito transmission and dangers to blood donors, and many showed uncertainty or incorrect knowledge regarding possible HIV transmission by biting, spitting, or use of public toilets. About a third of the children (51.4% of the boys and 18.7% of the girls) said they had experienced sexual intercourse, though only 20% reported being sexually active in the year preceding the survey. Three-quarters of the sexually experienced group said they knew how to use condoms, but only a third said there was any time when they had used protection during sexual intercourse. Overall, the results indicate that education efforts prior to the survey had been effective, but that reinforcement of such efforts as well as their extension into the primary schools is warranted. Further research directed at helping these efforts to encourage more meaningful changes in sexual behavior is also needed.

Acquired Immunodeficiency Syndrome↗
PubMed1991

The stressors and strains of health visiting: demands, supports, constraints and psychological health.

An empirical study investigated the work stressors and psychological strains experienced by health visitors in three areas of Hertfordshire and Bedfordshire. A questionnaire, based on Payne's model of occupational stress, probed the perceived demands, supports and constraints of the work and the coping strategies used by the health visitors. The research aimed to establish the extent and nature of strain using validated indicators of general anxiety and depression, to pinpoint specific features of the work which are associated with the strain measures, and to suggest possible changes to working practices. While health visitors found their jobs generally satisfying, a significant number of staff were under strain even though the mean levels of strain were lower than those observed in social workers and hospital-based nursing staff working with people who have a mental handicap, and little different from women who work in industry. Many aspects of the job were perceived to be demanding yet the demanding nature of cases was not related to strain measures. There were, however, interesting statistical relationships between strain scores and demands concerned with colleagues and managers and the amount of support a health visitor perceived.

Adaptation, Psychological↗
PubMed1991

Scales for rating motor impairment in Parkinson's disease: studies of reliability and convergent validity.

Study 1 examined the reliability of the ratings assigned to the performance of five sign-and-symptom items drawn from tests of motor impairment in Parkinson's disease. Patients with Parkinson's disease of varying severity performed gait, rising from chair, and hand function items. Video recordings of these performances were rated by a large sample of experienced and inexperienced neurologists and by psychology undergraduates, using a four point scale. Inter-rater reliability was moderately high, being higher for gait than hand function items. Clinical experience proved to have no systematic effect on ratings or their reliability. The idiosyncrasy of particular performances was a major source of unreliable ratings. Study 2 examined the intercorrelation of several standard rating scales, comprised of sign-and-symptom items as well as activities of daily living. The correlation between scales was high, ranging from 0.70 to 0.83, despite considerable differences in item composition. Inter-item correlations showed that the internal cohesion of the tests was high, especially for the self-care scale. Regression analysis showed that the relationship between the scales could be efficiently captured by a small selection of test items, allowing the construction of a much briefer test.

Activities of Daily Living↗
PubMed1991

Value of fibreoptic oesophago-gastro-duodenoscopy: experience with 4000 procedures at Kilimanjaro Christian Medical Centre, Moshi, Tanzania.

The paper presents the results of a retrospective study and the experiences with 4000 fibreoptic oesophago-gastro-duodenoscopies (EGD), which were performed at Kilimanjaro Christian Medical Centre (KCMC) between 1985 and 1989 in an open access service. Seventy per cent of all patients examined had abnormal findings with duodenal ulcer as the most frequent diagnosis (22%). Pyloric stenosis was seen in 6%, gastric ulcer in 5% and esophageal varices in 4% of all patients. High figures were found for carcinoma of the esophagus (4%) and malignancy of the stomach (5%). Gastritis was diagnosed in 11%. We consider fibreoptic EGD a cost effective and appropriate technology. Because of its high diagnostic yield, we advocate its use in certain centres in developing countries.

Adolescent↗
PubMed1991

Primary care in New York State: report and recommendations of the associated medical schools of New York.

Medical education in New York is unique in the country in its scope and its diversity. It is important, as we go forward, that these strengths be neither eroded nor compromised. The AMS member institutions are making a collective commitment to work together to promote changes that will improve medical education for all students by providing them with enriched experience in primary care. Our major resource is faculty. To whatever degree medical schools can influence career choice, it is essential to this aim that the best possible people are placed in the settings in which primary care is taught. The schools will intensify their efforts to recruit and retain such faculty and, in whatever way is appropriate to each institution, provide them with the stature needed to emphasize the value which the school places on primary care. The schools will also work to provide exposure to primary care early in a student's academic career given anecdotal evidence, at least, that such early experience can influence subsequent specialty choice. Finally, the medical schools will assume greater responsibility for graduate medical education. If, with state support, ambulatory teaching sites are developed, the schools will make every effort to assure that they are staffed with high-quality faculty. Residents and students must see primary care practiced with total commitment to quality. It is hoped that, with state-initiated improvements in the practice environment, the ultimate outcome will be an increase in the number of our graduates selecting primary care disciplines for their practices and locating in areas in need of physicians.2+ Corporation, and the Greater New York Hospital Association. We are ready to work with others toward our common objectives, and we call on all of those who share these concerns to participate with us.

Career Choice↗
PubMed1990

New York's statewide approach to increase the number of minority applicants to medical school.

The Associated Medical Schools of New York (AMS), a consortium of 13 public and private medical schools, has identified the problem of low minority enrollment as its top priority issue. Over the last six years, the consortium has established a multifaceted, statewide effort aimed at increasing the pool of qualified minority applicants. The programs include academic enrichment for precollege and college students, recruitment conferences, and a program to attract minority applicants to residency training in New York. The key to this effort is the work of the AMS Office of Minority Affairs, which provides statewide oversight and coordinates these programs. The consortium approach has proven attractive to both private philanthropy and government funding sources and provides a mechanism for evaluation. The most valid evaluation will occur in about three years, when graduates of the precollege program begin to apply to medical school.

Education, Medical↗
PubMed1990

Persistent nonproductive infection of Epstein-Barr virus-transformed human B lymphocytes by human immunodeficiency virus type 1.

We have studied the interaction of different strains of human immunodeficiency virus type 1 (HIV-1) with an Epstein-Barr virus-transformed human B-lymphocyte line, X50-7. Previously we found that some HIV-1 strains replicated rapidly and were exclusively cytolytic; others induced persistent noncytopathic infection associated with continued shedding of extracellular virus (K. Dahl, K. Martin, and G. Miller, J. Virol. 61:1602-1608, 1987). We now describe a third form of cell-virus relationship in which infection by strain IIIB is maintained in a highly cell-associated state in a small subpopulation (less than 2%) of X50-7 cells. Neither viral subcomponents nor infectious virus was detectable in culture supernatants; however, the carrier lines were fusogenic and HIV-1 could be recovered following prolonged cocultivation with susceptible cells. In these chronic carrier cultures, virions were not seen budding at the cell surface, but a few were found within cytoplasmic vesicles. HIV-1 infection of first- and second-generation cell subclones of the carrier cell line rapidly evolved from a productive to a cell-associated state. There were low levels of HIV DNA, and RNA in the fusogenic secondary clones, but most clones lacked HIV-1 DNA, failed to express HIV-1 RNA, and exhibited no properties associated with HIV-1 infection. The experiments indicate that HIV-1 can be sequestered in human B lymphocytes. The cell cloning experiments introduce the possibility that the HIV-1 provirus may be lost from some lymphocytes.

B-Lymphocytes↗
PubMed1989

Problems in applying expert system technology to radiographic image interpretation.

A prototype expert system was developed to study the problems applying expert system technology to radiographic image interpretation. The Radiographic Image Interpretation System (RIIS) was developed on a microcomputer using Turbo Prolog, a low cost implementation of the prolog programming language. The present implementation of RIIS was developed to highlight potential problems in applying expert system technology in the evaluation of radiographic images. It was believed that the evaluation of this prototype expert system should include a large number of users unfamiliar with the program's use as this would probably be the case in clinical use of an image interpretation expert system. At present, the expert system deals with a limited domain of focal bony lesions. Twenty cases of pathologically proven bony lesions of varying difficulty were used to evaluate potential problems in the use of this expert system technology. RIIS, with the 20 sample cases, was presented as an exhibit at the 1987 Radiological Society of North America (RSNA) meeting to evaluate the potential problems with inexperienced users. These results were compared with those of experienced users. When a musculoskeletal radiologist, familiar with the programs use, provided the "proper description," the program averaged the correct diagnosis in the top five 80% of the time. During the program's use at the RSNA meeting, the program selected the correct diagnosis in the top five 22% of the time.

Bone Neoplasms↗
PubMed1988

Involvement of arginine residues in the activation of calmodulin-dependent 3',5'-cyclic-nucleotide phosphodiesterase.

Pretreatment of an affinity-purified, brain calmodulin (CaM)-dependent phosphodiesterase (EC 3.1.4.17) with p-hydroxyphenylglyoxal (pHPG), a specific arginine-modifying reagent, resulted in a time-dependent loss in CaM-stimulated hydrolysis of cyclic AMP and cyclic GMP with no change in basal, CaM-independent activity. The loss in CaM-stimulated activity was preceded by a transient increase in CaM-dependent activity. Phenylglyoxal was 10-fold more effective than pHPG in promoting the loss of CaM-stimulated activity with a second-order rate constant of 13.3 M-1 min-1. Other arginine-modifying reagents, 1,2-cyclohexanedione and 2,3-butanedione, were not effective. The pHPG-modified enzyme was activated by 100 microM lysophosphatidylcholine to levels comparable to CaM-stimulated activity. The arginyl-modified enzyme was also activated by chymotrypsin and trypsin but not to the extent of the untreated enzyme stimulated with CaM. The presence of CaM during chemical modification with pHPG protected the enzyme from inactivation. Both the extent of activation and the amount of CaM necessary for 50% maximal activation were affected by pHPG treatment of the enzyme. The approximate number of modified arginines estimated by [7-14C]phenylglyoxal incorporation and amino acid analysis after complete inactivation of CaM stimulation was seven residues per catalytic subunit assuming enzyme homogeneity. The Stokes radius and sedimentation coefficient of the enzyme were unchanged by the modification. These results suggest that arginine residues are critical for functional interaction between phosphodiesterase and CaM and that controlled modification can selectively alter CaM-stimulated enzyme activity.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1988

Role of cytoplasmic vacuoles in varicella-zoster virus glycoprotein trafficking and virion envelopment.

Varicella-zoster virus (VZV) encodes several glycoproteins which are present on both mature viral envelopes and the surfaces of infected cell membranes. Mechanisms of VZV glycoprotein transport and virion envelopment were investigated by both continuous radiolabeling and pulse-chase analyses with tritiated fucose in VZV-infected cells. We studied in detail the large cytoplasmic vacuoles which were present in infected cells but absent from uninfected cells. The specific activity in each subcellular compartment was defined by quantitative electron microscope autoradiography, using a cross-fire probability matrix analysis to more accurately assess the individual compartment demarcated by the silver grains. By these techniques, we documented a progression of activity originating in the Golgi apparatus and traveling through the post-Golgi region into virus-induced cytoplasmic vacuoles and finally to areas of the cellular membrane associated with the egress of viral particles. Significant amounts of radiolabel were not observed in the nucleus, and only low levels of radiolabel were associated with the cellular membrane not involved with the egress of viral particles. In addition, immunolabeling of Lowicryl-embedded VZV-infected cells demonstrated the presence of VZV glycoproteins within cytoplasmic vacuole membranes as well as on virion envelopes. These observations suggested that cytoplasmic vacuoles harbored VZV-specified glycoproteins and were also the predominant site of VZV virion envelopment within the infected cell. Neither enveloped nor unenveloped viral particles were observed within the Golgi apparatus itself.

Autoradiography↗
PubMed1987

The effects of an anti-I-Ab antibody on murine host resistance to Listeria monocytogenes.

Infection with Listeria monocytogenes stimulates T cell proliferation and T cell-derived lymphokine production. The release of lymphokines, in turn, "activates" macrophages, enhancing their bactericidal capacity. Because prior studies suggest that I-A+ accessory cells play a critical role in this pathway, we assessed the effects of an anti-I-A antibody on the murine host resistance to listerial infection. To this end, we infused Listeria into control C57BL/6 mice (I-Ab haplotype) and mice of the same strain which had been pretreated 18 hr earlier with D3137 (a monoclonal IgG2a anti-I-Ab,d antibody). Preliminary studies demonstrated that this antibody can markedly inhibit antigen-induced proliferation of Listeria-dependent T cells in vitro and (at a dose of 1 mg/animal) can markedly reduce I-A expression on splenocytes in vivo. Even though D3137 pretreatment prevented the splenomegaly normally observed after Listeria infusion into mice, it protected animals infused with otherwise lethal concentrations of Listeria. Because antibody-treated animals had sevenfold fewer organisms in their spleens 18 hr after infection and 1000-fold fewer organisms than control animals 3 days after infection, improved survival resulted from an antibody-induced increase in the bactericidal capacity of the MPS. Protection was not noted when C1.18.4 (an IgG2a myeloma protein without known antibody activity) was infused into C57BL/6 mice or when D3137 was infused in B10.BR (I-Ak) mice. D3137 also protected (B10 X B10.BR)F1 mice (which are hybrids bearing I-Ab and I-Ak), suggesting that complete blockade of antigen presentation is not a prerequisite for its protective action. Further studies into the mechanism for these effects may provide new insights into the pathophysiology of MPS activation in response to immunologic challenge.

Animals↗
PubMed1987

Attention, autonomic arousal, and personality in behaviorally disordered children.

This study assessed the construct validity of the Revised Behavior Problem Checklist (RBPC) by measuring attention, autonomic arousal, and personality in 40 behaviorally disordered children aged 7 to 15 years. Conduct Disorder and Socialized Aggression subscales were characterized by high Psychoticism, Impulsivity, and Lie personality scores, by lower heart rate levels, and by more errors on a continuous performance reaction-time task. Conversely, Attention Problems, Anxiety Withdrawal, and Motor Excess were characterized by greater variability in reaction times. Conduct Disorder alone was related to an external locus of control, while only Attention Problems was characterized by low scores on the WISC Freedom from Distraction factor. These differential relationships suggest (a) support for the construct validity of the RBPC, (b) that antisocial behavior and hyperactivity/attention deficits are dissociated disorders, and (c) that hyperactivity/attention deficits may be characterized by fluctuations in the allocation of attentional resources rather than a core structural deficit in attention.

Adolescent↗