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Biomedical subjects

S Day

Publications and source records attributed to S Day.

At least 55 records · Page 3Linked to original sources
PubMed2000

Health issues associated with increasing use of "crack" cocaine among female sex workers in London.

OBJECTIVES: To document changes in "crack" cocaine use in the sex industry in London, and to assess health risks associated with the drug. DESIGN: Two serial cross sectional surveys. SUBJECTS: Sex workers interviewed in 1989-9 and 1995-6. MAIN OUTCOME MEASURES: Self reported use of crack cocaine; clinical history of sexually transmitted infection and pregnancy, clinical outcomes. RESULTS: The proportion of women reporting crack use increased significantly from 22/193 (11%) in 1989-91 to 48/143 (34%) in 1995-6. Women in all the main prostitution sectors reported crack use. Crack users had been working in prostitution for longer, were more likely to have worked on the streets, to inject drugs, and to have a partner who injected. Crack use was associated with termination of pregnancy and with hepatitis C infection. The association with hepatitis C was partially explained by confounding with injecting drug use. CONCLUSIONS: Crack use is more common and less problematic than clinical presentation suggests. Use has increased over the past decade, and is associated with hepatitis C infection and termination of pregnancy. It is possible that crack use facilitates hepatitis C transmission due to oral lesions from smoking. Crack use can be difficult to identify because of the stigma of being labelled a "crack whore," therefore information on crack might usefully be integrated into general health promotion material on drugs and safer sex.

Abortion, Induced↗
PubMed2000

An analytic method for longitudinal mortality studies.

Our knowledge of mortality risks comes largely from longitudinal (cohort) studies. The most commonly used analytic tool is the Cox proportional hazards model for survival analysis. An alternative approach is a simple cross-sectional analysis of person-years. The key to the method is logistic regression, where the outcome variable is lived/died in the given year and the explanatory variables are age, sex, and other potential risk factors. This approach can be used to model any dichotomous outcome and has several important advantages over the more traditional survival analysis. As an example, we compare the two methods using a large data base of patients with spinal cord injury.

Adolescent↗
PubMed1999

Plasminogen II accumulates five times faster than plasminogen I at the site of a balloon de-endothelializing injury in vivo to the rabbit aorta: comparison with other hemostatic proteins.

In the rabbit blood stream, plasminogen circulates as two glycoforms, plasminogen I (PLG-I) and plasminogen II (PLG-II), in a molar ratio of 1:2.2. To compare their relative behaviors toward a site of vascular injury, radiolabeled samples of PLG-I and PLG-II were coinjected intravenously into NZW rabbits before inducing a de-endothelializing (balloon catheter) injury to the thoracic aorta. At various times (5 to 60 minutes) after injury, each rabbit was anesthetized and exsanguinated, the aorta was excised, and the radioactivity per centimeters squared of aortic intima-media (IM) was measured relative to that of blood at exsanguination. The uptake of iodine 125-labeled PLG-I and iodine 131-labeled PLG-II showed that the IM was essentially saturated by both glycoforms by 30 to 40 minutes after injury. Extrapolation of the flux rates to 1 minute after injury indicated that the uptake of PLG-II (2.4 pmol/min/cm2) exceeded PLG-I (0.5 pmol/min/cm2) almost five-fold. This result is consistent with an earlier report (Metabolism 1994;43:1430-7) that PLG-II is released by the liver and catabolized in vivo approximately five times faster than PLG-I. By molar comparison, the flux of total plasminogen (ie, PLG-I plus PLG-II) into the injured aorta wall in vivo was 2.4 times greater than that for prothrombin. Assuming both zymogens are converted to their respective proteases within the wound site, then approximately 2 to 3 molecules of plasmin are released for each molecule of thrombin in vivo. The possible significance of this plasmin:thrombin ratio is discussed in respect to the turnover of fibrin(ogen) within the site of vascular injury.

Animals↗
PubMed1999

A novel HLA allele, HLA-B*5113, identified in the Kolla Amerindians of North-West Argentina.

A novel HLA-B51 allele, B*5113, was identified in a Kolla Amerindian individual from North-West Argentina. HLA-B*5113 differs from B*51011 by two nucleotide substitutions, one synonymous, the other nonsynonymous. The resulting amino acid difference at residue 116 in the HLA-B molecule's peptide binding site is likely to affect the nature of the peptides which bind to this molecule. The finding of this novel allele supports previous findings of increased diversity at HLA-B in Amerindian groups.

Alleles↗
PubMed1999

Identification of a new variant, HLA-Cw*1507, differing from Cw*1502 only at the KIR-related dimorphism of codons 77 and 80.

We describe here a novel allele, HLA-Cw*1507, identified by polymerase chain reaction using sequence-specific primers (PCR-SSP) and sequence-based typing (SBT). Cw*1507 is similar to Cw*1502 with differences at nucleotide positions 302 (A to G) and 312 (A to C) in exon 2. The substitutions observed in Cw*1507, change codon 77 from AAC (asparagine) to AGC (serine) and codon 80 from AAA (lysine) to AAC (asparagine), compared to Cw*1502. Residues 77 and 80 of HLA-C alleles are located in the alpha 1 domain, where they can influence interaction between antigenic peptides and the T-cell receptor. Also, the dimorphism at these residues from asparagine and lysine to serine and asparagine, respectively, are known to modulate interaction with the natural killer (NK) cell killer inhibitory receptor (KIR). The new HLA-Cw*1507, together with Cw*1502, represents the fourth pair of HLA-C alleles differing only at the KIR-related dimorphic codons 77 and 80.

Base Sequence↗
PubMed1999

Identification of an HLA-A11 serological variant and its characterization by sequencing based typing.

We have identified an HLA-A11 variant allele, A*1105, segregating in a Caucasoid family. The variant antigen expressed by this allele failed to cross-react with most Caucasoid anti-HLA-A11 antisera tested. Sequencing based typing has been used to characterize this new allele and this showed that it has a novel mutation at a polymorphic position (502) in exon 3. In comparison with A*1101, the mutation (A-->G) results in an amino acid change from positively-charged lysine to negative glutamate and this may explain the altered HLA-A11 serological profile exhibited by this antigen. The new allele was found in a patient with acute lymphoid leukaemia (ALL), her father and two siblings.

Alleles↗
PubMed1999

Indirect evidence of human skeletal muscle damage and collagen breakdown after eccentric muscle actions.

Indirect markers of muscle damage and collagen breakdown were recorded for up to 9 days after a bout of concentric, followed by a bout of eccentric, muscle actions. Nine untrained participants performed two bouts of 50 maximum effort repetitions on an isokinetic dynamometer (angular velocity 1.05 rad x s(-1), range of motion 1.75 rad). An initial concentric bout of muscle actions was followed by an eccentric bout 21 days later, using the same knee extensors. Concentric actions induced no changes in maximum voluntary isometric contraction force (MVC), nor induced any changes in the serum enzyme activities of creatine kinase, a lactate dehydrogenase isoenzyme (LDH-1), or alkaline phosphatase. Similarly, concentric actions induced no change in markers of collagen breakdown, namely plasma hydroxyproline and serum type 1 collagen concentration. In contrast, eccentric actions induced a 23.5+/-19.0% (mean+/-s) decrease in MVC immediately post-exercise (P < 0.05), and increased the serum enzyme activities of creatine kinase and LDH-1 to 486+/-792 and 90+/-11 IU.l(-1) respectively on day 3 post-exercise, and to 189+/-159 and 96+/-13 IU x l(-1) respectively on day 7 post-exercise (all P< 0.05). Eccentric actions induced no significant changes in plasma hydroxyproline, but increased collagen concentration on days 1 and 9 post-exercise (48.6% and 44.3% increases above pre-exercise on days 1 and 9 respectively; both P < 0.05). We conclude that eccentric but not concentric actions may result in temporary muscle damage, and that collagen breakdown may also be affected by eccentric actions. With caution, indices of collagen breakdown may be used to identify exercise-induced damage to connective tissue.

Adult↗
PubMed1999

Implementation of a clinical pathway system in maternal newborn care: a comprehensive documentation system for outcomes management.

This article describes the design, implementation, and evaluation of an interdisciplinary clinical pathway system for maternal newborn care in a perinatal regional referral institution. Core issues in the design of this system are addressed to promote outcomes management and ongoing performance improvement. A discussion of the implementation follows, illustrating the lessons learned, changes made, and associated evaluation. This clinical pathway system has improved communication and collaboration among all disciplines, enhanced the discharge coordination process, and established protocols available to all members of the health care team.

Adult↗
PubMed1999

Risky business: health and safety in the sex industry over a 9 year period.

OBJECTIVES: To assess whether a previously established low sexually transmitted infection/HIV risk in prostitutes in London has been sustained, and to measure other occupational risks, including mortality. DESIGN: 9 year prospective study in west London. SUBJECTS: 402 prostitutes recruited from 1985 to 1991, 320 were followed up for 675 person years to 1994. MAIN OUTCOME MEASURES: Condom use in commercial and non-commercial sex; viral and bacterial sexually transmitted infection at initial and follow up visits; death. RESULTS: Condom use increased significantly from 1986 to 1993 and protected the majority of commercial sexual contacts. Baseline prevalence: HIV 1.3%, hepatitis C 6.7%, hepatitis B 6.6%, syphilis 2.3%, HTLV-I/II 0.4%, gonorrhoea 3.0%, chlamydia 8.2%, genital herpes 16.8%. Incidence (per 100 person years): HIV 0.2, hepatitis C 0.3, gonorrhoea 5.6, chlamydia 12.6, genital herpes 6.5. Viral infections were associated with injecting drug use and non-British nationality; bacterial infections were associated with numbers of non-commercial partners but not with sexual contacts at work. Four women died during the course of the study; two had AIDS, two were murdered. This mortality of 5.93 per 1000 person years was 12 times the expected rate for women of a similar age. CONCLUSIONS: This study shows that it is possible to have a larger number of sexual partners and remain free from sexually transmitted infections provided that condoms are used consistently: there has been a sustained increase in condom use in the sex industry. None the less, prostitutes are at increased risk of sexually transmitted infections, primarily through non-commercial sexual partnerships. Infectious diseases are only one of the risks facing prostitutes, as illustrated by the mortality from violence as well as from HIV infection.

Adolescent↗
PubMed1999

Flow cytometry and squamous cell carcinoma of the maxillary sinus: A possible prognostic indicator for multimodality intervention.

Malignant tumors of the paranasal sinuses constitute less than 1% of all malignancies. Unfortunately, few prognostic factors have been identified regarding the efficacy of interventional therapy. Patients with carcinoma of the maxillary sinus frequently present with an advanced stage of disease and multimodality therapy is often proposed. Although some tumors appear to be more sensitive to preoperative chemotherapy and radiation therapy, a method of predicting and evaluating tumor behavior has not been recognized. Introduced as a means of identifying cell populations with abnormalities in total DNA content, flow-cytometric DNA analysis provides a quick and reliable means of tumor characterization for many malignancies. Although nuclear DNA content has been implicated as a prognostic factor in an increasing number of tumor types, current data on the role of DNA content in head and neck carcinoma is conflicting and incomplete. To evaluate the role of flow-cytometric DNA analysis in predicting therapeutic alternatives, 22 patients with squamous cell carcinoma of the maxillary sinus were reviewed. Patient outcome and histopathologic grade were retrospectively compared with flow-cytometric evaluations of paraffin-embedded formalin-fixed tumor specimens. Four of sixteen tumors (25%) were found to be aneuploid and were also associated with an increased survival rate (p < 0.01). This initial data emphasizes the possible usefulness of DNA measurement for characterization of squamous cell carcinoma of the maxillary sinus and stresses the need for further evaluation.

Adult↗
PubMed1999

Delusional ideation in religious and psychotic populations.

OBJECTIVES: Previous research into schizotypy has shown that certain groups of people have similar experiences to the positive symptoms of schizophrenia but remain functioning members of society, such as those with profound religious experiences (Jackson & Fulford, 1997). METHOD: The focus of the present study was to explore the incidence of delusional ideation in New Religious Movements (NRMs). Hare Krishnas and Druids were compared to two control groups (non-religious and Christian), and to deluded, psychotic in-patients on two delusions measures. RESULTS: As predicted, individuals from the NRMs scored significantly higher than the control groups on all the delusional measures apart from levels of distress. They did not show as much florid symptomatology as the psychotic patients, but could not be differentiated from the deluded group on the number of delusional items endorsed on the Peters et al. Delusions Inventory (PDI; Peters, Day & Garety, 1996), or on levels of conviction. However, they were significantly less distressed and preoccupied by their experiences. No differences were found between the two control groups on any of the delusional measures, suggesting that religious beliefs per se do not account for the NRMs members' scores. DISCUSSION: These findings provide further support for, first, the notion of a continuum between normality and psychosis and, second, for the necessity to consider the multidimensionality of delusional beliefs.

Adaptation, Psychological↗
PubMed1999

Changes in indices of antioxidant status, lipid peroxidation and inflammation in human skeletal muscle after eccentric muscle actions.

This study investigated the effects of chronic muscle inflammation on indices of antioxidant status and muscle injury after eccentric exercise. Eight subjects each performed 70 maximal voluntary eccentric muscle actions on an isokinetic dynamometer, using the knee extensors of a single leg. Venous blood samples were collected into serum and EDTA tubes 5 and 3 days before exercise, immediately before exercise, and then again on days 3, 4, 5, 6, 7, 10 and 12 after the bout. Needle biopsies were taken from the vastus lateralis of six subjects, a week before exercise (baseline), and again on days 4 and 7 post-exercise. The concentrations of malondialdehyde in plasma and muscle were used as markers of lipid peroxidation. Creatine kinase activity, beta-glucuronidase activity and total antioxidant capacity were determined in serum. In muscle, aqueous and bound total antioxidant capacity, the aqueous sulphydryl concentration, and beta-glucuronidase and glucose-6-phosphate dehydrogenase activity were determined. No changes were detected in serum total antioxidant capacity, serum creatine kinase and beta-glucuronidase after the baseline biopsy. After exercise serum creatine kinase and beta-glucuronidase were elevated although other serum measures were unchanged. In muscle, aqueous and bound total antioxidant capacity, sulphydryls, glucose-6-phosphate dehydrogenase and beta-glucuronidase were all elevated. Despite evidence of inflammation in this study, muscle antioxidant status was not compromised, and malondialdehyde was unaltered in muscle and plasma. Therefore, this study provides no evidence that chronic muscle inflammation compromises antioxidant status or increases lipid peroxidation.

Adult↗
PubMed1998

Double data entry: what value, what price?

We challenge the notion that double data entry is either sufficient or necessary to ensure good-quality data in clinical trials. Although we do not completely reject that notion, we quantify some of the effects that poor quality data have on final study results in terms of estimation, significance testing, and power. By introducing digit errors into simulated blood pressure measurements we demonstrate that simple range checks allow us to detect (and therefore correct) the main errors that impact the final study results and conclusions. The errors that cannot easily be detected by such range checks, although possibly numerous, are shown to be of little importance in drawing the correct conclusions from the statistical analysis of data. Exploratory data analysis cannot identify all errors that a second data entry would detect, but on the other hand, not all errors that are found by exploratory data analysis are detectable by double data entry. Double data entry is concerned solely with ensuring, to a high degree of certainty, that what is recorded on the case record form is transcribed into the database. Exploratory data analysis looks beyond the case record form to challenge the plausibility of the written data. In this sense, the second entering of data has some benefit, but the use of exploratory data analysis methods, either as data entry is ongoing or at the end of data entry and as the first stage in an analysis strategy, should always be mandatory.

Algorithms↗
PubMed1998

Sexual networks: the integration of social and genetic data.

New methods for studying sexual networks are presented, drawing upon routine procedures followed in genitourinary medicine clinics in the UK for tracing partners and identifying strains of infection. The routine social procedures were developed to incorporate a structured interview. The routine microbiological diagnosis of gonorrhoea was augmented by phenotyping and the development of new genetic techniques for the fine discrimination of gonococcal strains (opa-typing). Selected results from a study in Sheffield, UK show that each method has limitations, when conducted separately, but these are minimised when the methods are combined. Moreover, the use of simple and routine methods of data collection resolve issues of scale and sample that have beset other network studies, as they provide a means of covering a larger and defined population. Popular concepts about these methods are discussed in the conclusion. The integrated approach employed in our research raises questions both about social methods, 'of people who lie, particularly when they talk about sex', and about microbiological methods, 'of genes that tell the truth' and bypass what people say and think altogether. We argue that these stereotypes are misleading insofar as they suggest that genetic techniques can substitute for the social, and we suggest that even the finest discrimination of organisms at the genetic level will never obviate the need for their interpretation in the light of social data.

Adult↗
PubMed1998

Sexual networks and the transmission of HIV in London.

This paper discusses ways in which empirical research investigating sexual networks can further understanding of the transmission of HIV in London, using information from a 24-month period of participant observation and 53 open-ended, in-depth interviews with eighteen men and one woman who have direct and indirect sexual links with each other. These interviews enabled the identification of a wider sexual network between 154 participants and contacts during the year August 1994-July 1995. The linked network data help to identify pathways of transmission between individuals who are HIV+ and those who are HIV-, as well as sexual links between 'older' and 'younger' men, and with male prostitutes. There appears to be considerable on-going transmission of HIV in London. The majority of participants reported having had unprotected anal and/or vaginal sex within a variety of relationships. The implications of these findings for policies designed to prevent the transmission of HIV are discussed.

Adult↗
PubMed1998

Identification of an HLA-C variant allele, Cw*0805, by sequencing based typing.

We have identified a variant HLA-C allele, Cw*0805, in DNA isolated from a blood sample used in the UK National External Quality Assessment Scheme for Histocompatibility and Immunogenetics. The DNA was initially typed by PCR-SSP and PCR-SBT as Cw*0802, 1602 with a single mismatch in exon 2 of one of the alleles. The two HLA-C alleles were separated by locus- and allele-specific PCRs and sequencing analysis showed that the Cw*0802 allele was variant in this sample, with a single mismatch in exon 2 at position 289.

Alleles↗