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Biomedical subjects

K Lawrence

Publications and source records attributed to K Lawrence.

At least 37 records · Page 2Linked to original sources
PubMed1997

Quality of life in patients undergoing inguinal hernia repair.

Inguinal hernia repair is one of the most common surgical procedures undertaken in the NHS. Despite this, no previous work has examined quality of life in this patient group. This study examines quality of life preoperatively and at 3 and 6 months postoperatively in 140 patients undergoing inguinal hernia repair in the context of a randomised controlled trial of laparoscopic versus open hernia repair. Surgery was undertaken on a day case basis, and quality of life was assessed using the Short Form 36 (SF36). In the initial phase of the study, 57% of those screened for suitability met the study inclusion criteria and were randomised. No significant differences were found between laparoscopic and open hernia repair in terms of quality of life at 3 and 6 months postoperatively. No difference was found between 3 and 6 month scores, suggesting that patients had already made a good recovery by 3 months. A significant improvement was found between preoperative and postoperative scores, with the greatest change arising on dimensions assessing pain, physical function, and role limitation owing to physical restriction. After standardising for age, sex, and social class, a comparison of the hernia patients to population norms for the SF36 was consistent with improvement from preoperative to postoperative assessment. This study has demonstrated the improvement in quality of life in patients undergoing elective inguinal hernia repair by experienced surgeons on a day case basis. It has also demonstrated the feasibility of assessing quality of life using generic measures in this patient group. Further work in this area is required. Ultimately, the priority given to elective inguinal hernia repair will depend on how the demonstrated benefits compare with those derived from other elective surgical procedures.

Adolescent↗
PubMed1997

Pharmaceutical policies in Canadian family medicine training. Survey of residency programs.

OBJECTIVE: To determine whether family medicine residency training programs have formal policies regarding interactions between residents and the pharmaceutical industry, to identify existing practices, and to find out what issues in industry-physician interaction are addressed during the 2-year core curriculum training in Canada. DESIGN: Mailed survey using a questionnaire. SETTING: The 16 Canadian residency training programs in family medicine. PARTICIPANTS: Program directors of all 16 Canadian family medicine residency training programs replied. MAIN OUTCOME MEASURES: Number of programs with formal pharmaceutical policies; number of programs offering formal curriculum coverage of related topics in the field; program practices regarding industry sampling, detailing, sponsorship, and access. RESULTS: Only four of the 16 programs have formal policies or guidelines. Topics generally covered in core curriculum included critical appraisal (13/16) and cost trends (11/16). Few programs address determinants of prescribing (5/16), marketing techniques (4/16), provincial drug access programs (6/16), or the Canadian Medical Association guidelines on physician-industry interaction (5/16). Industry presence and sponsorship in family medicine training is notable, and screening is limited. Great variation exists, and programs are interested in future initiatives. CONCLUSIONS: Family medicine training in Canada is attempting to address pharmaceutical issues. Interest is strong, but these issues need to be given more emphasis.

Canada↗
PubMed1996

An economic evaluation of laparoscopic versus open inguinal hernia repair.

BACKGROUND: The rapid and widespread introduction of minimal access surgery has major implications for the National Health Service. It cannot be assumed that replacing an open procedure with a minimal access alternative will be cost-effective. Laparoscopic inguinal hernia repair is a procedure for which the potential economic benefits are particularly unclear. It is currently being adopted in many centres, although limited evidence on its clinical and cost-effectiveness exists. METHODS: This economic comparison of laparoscopic versus open hernia repair was undertaken on data collected on 104 patients undergoing surgery on a day case basis, in the context of a randomized controlled trial. RESULTS: The mean total health service cost of laparoscopic repair was 1074 pounds versus 489 pounds for open repair [mean difference in total health service costs 583 pounds; 95 percent confidence interval (CI) 265 pounds-904 pounds]. This difference was largely accounted for by the difference in theatre costs. Laparoscopic repair remained significantly more expensive for most but not all of the scenarios explored in the sensitivity analysis. The direction of the cost-effectiveness ratio was not sensitive to assumptions about long-term recurrence. Neither was it sensitive to halving the operating time in the laparoscopic arm of the trial. When both operating time and the costs of consumables were reduced, laparoscopic repair remained more expensive, but results for this scenario did not achieve statistical significance on this sample size. CONCLUSIONS: Laparoscopic hernia repair appears an expensive option in most plausible situations. Furthermore, many uncertainties still exist about long-term outcome after the procedure and about the conditions necessary to maximize cost-effectiveness. Large-scale randomized studies to evaluate laparoscopic hernia repair are currently under way to address these issues. We suggest that further evidence is awaited before this technology is further diffused.

Adolescent↗
PubMed1996

Relationship between health status and postoperative return to work.

BACKGROUND: Time back to work or normal activity is often regarded as an outcome measure of interest after surgery. It has recently been used as a way of quantifying the benefits of minimal access surgery. However, the extent to which variation in time back to normal reflects differences in health status is unclear. METHODS: The relationship was examined in 140 patients recovering from inguinal hernia repair. A multi-dimensional measure of health status, the Short Form 36 (SF-36), was administered preoperatively, and at ten days and six weeks postoperatively. The relationship between scores on the SF-36 dimensions and return to normal activity was examined using correlation statistics and stepwise regression. RESULTS: Health status dimensions measuring role limitation owing to physical restriction at 10 days and 6 weeks, and role limitation owing to mental problems at ten days were associated with time to return to normal on univariate analysis. Social class was also strongly associated. Using stepwise regression these two dimensions of health status together explained 33 per cent of the variance in time to normal. Other factors unrelated to health status clearly contributed to this outcome. CONCLUSION: Time back to normal activity postoperatively is influenced by a number of factors unrelated to health status and is an unreliable proxy for it. Time to normal is therefore, not a good outcome measure for quantifying the benefits of surgical interventions. Claims currently being made to justify investment in some minimal access interventions should be interpreted in the light of this.

Activities of Daily Living↗
PubMed1995

Randomised controlled trial of laparoscopic versus open repair of inguinal hernia: early results.

OBJECTIVE: To establish the safety, short term outcome, and theatre costs of transabdominal laparoscopic repair of inguinal hernia performed as day surgery. DESIGN: Randomised controlled trial. The control operation was the two layer modified Maloney darn. SETTING: Teaching hospital and district general hospital. SUBJECTS: 125 men randomised to laparoscopic or open repair of inguinal hernia. OUTCOME MEASURES: Morbidity, postoperative pain and use of analgesics, quality of life, and theatre costs. Outcome was assessed by questionnaires administered to patients daily for 10 days and at six weeks postoperatively and by outpatient review at six weeks. Return to normal activity was assessed by questionnaire at three months. RESULTS: One vascular complication (2%) occurred in the group that had open repair. Seven complications (12%) including vessel injury and early recurrence arose in the group that had laparoscopic repair (difference in complication rate 10% (95% confidence interval 4% to 18%; P = 0.02). Pain scores and quality of life assessed by the short form 36 showed a significant benefit to the group that had laparoscopic repair in the early postoperative period. Return to normal activity was not significantly different between the two groups. Total theatre costs were higher in the group that had laparoscopic repair (mean cost for laparoscopic repair 850 pounds (622 pounds to 1078 pounds); mean cost for open repair 268 pounds (245 pounds to 292 pounds)). CONCLUSIONS: Because of the greater complication rate and higher theatre costs for laparoscopic repair and the patient outcome preferences expressed, the results of larger trials of clinical and cost effectiveness using recurrence as the primary outcome measure should be known before laparoscopic herniorrhaphy is widely adopted.

Adult↗
PubMed1995

Sensitivity to change of health status measures in a randomized controlled trial: comparison of the COOP charts and the SF-36.

This study compared the sensitivity to change of comparable dimensions of a multi-item multi-dimensional health status measure (the SF-36) with the equivalent single item domains on the Dartmouth COOP charts. One hundred and twenty nine patients were randomized to either day case laparoscopic surgery (n = 60) or open inguinal hernia repair (n = 69). Respondents completed the SF-36 and COOP charts at baseline (prior to surgery) and at follow up at 10 days and 6 weeks. Equivalent dimensions of physical functioning, mental health/emotional condition, social activities, pain and overall condition/general health on the two questionnaires were compared. Despite slightly different pictures of change provided by the physical functioning and 'overall condition/general health' dimensions the general picture of change provided by the two instruments was similar. At 10 days, patients who underwent open surgery reported far greater levels of dysfunction than those who underwent laparoscopic surgery on both questionnaires. At 6 weeks the pain dimension of both questionnaires indicated a large improvement from baseline, whilst no other domain on either questionnaire for either group indicated such improvement. The general picture of change provided by the two measures was similar. The results suggest that both the SF-36 and the COOP charts may prove suitable for the assessment of health perception outcomes in surgical clinical trials. Differences on certain domains were caused in large measure by the nature of the questions posed. The study once again highlights the importance of checking item content to determine the suitability of any particular measure for a given study.

Adult↗
PubMed1994

Role of vif during packing of the core of HIV-1.

The viral infectivity factor gene vif of human immunodeficiency virus type 1 (HIV-1) has been shown to enhance the cell-free infectivity of HIV-1 virus particles. Previous studies have demonstrated that vif increases viral infectivity at the time of virus production, most likely by affecting viral protein processing, virus assembly, or virus maturation. The effect of vif on the assembly and maturation of HIV-1 propagated in CEM, Jurkat, and SupT1 cells was examined by electron microscopy and goniometer analysis. CEM and Jurkat cells are nonpermissive and partially permissive for the replication of vif--defective viruses, respectively, while SupT1 cells are completely permissive. In CEM and Jurkat cultures, the morphology of immature vif+ and vif- virions was similar but immature virus particles were observed at a slightly higher frequency in cultures infected with the vif- virus. At later stages of virus maturation, however, nonhomogeneous packing of the core was detected in the majority of vif- virus particles produced in CEM and Jurkat cells. In the absence of vif, the cone-shaped virus core contained dense material in its broad end but, in contrast to vif+ virions, the material inside its narrow end appeared transparent. The narrow part of the vif- virus core was surrounded by a shell and was attached to the viral envelope by a core-envelope link structure. Vif- virus particles with a lateral body of core material adjacent to the viral envelope were also observed more frequently in CEM and Jurkat cultures. In contrast, in SupT1 cultures the morphology of mature vif+ and vif- virus particles was similar. These results suggest that vif is associated with an effect during the final stages of packing of the viral nucleoprotein core. This effect may be important for the infectivity of HIV-1 virus particles.

Cell Line↗
PubMed1994

Permittivities of fresh fruits and vegetables at 0.2 to 20 GHz.

Permittivities, moisture contents, tissue densities, and total soluble solids data were determined for samples of twenty-three kinds of fresh fruits and vegetables at 23 degrees C. Permittivities were measured at 41 frequencies between 200 MHz and 20 GHz with an open-ended coaxial-line probe and a microwave network analyzer. Results of the permittivity measurements are presented graphically, and dielectric constant and loss factor values at six frequencies across the range are tabulated along with sample descriptions and moisture, density, and total soluble solids data. Although specific values differ, the dielectric constant decreases steadily with increasing frequency, dropping more rapidly at frequencies above 5 GHz. Values for the loss factor decrease as frequency increases above 200 MHz to a broad minimum in the 1- to 3-GHz region and then increase again as the frequency approaches 20 GHz. The dielectric behavior of the fruit and vegetable tissues appears to be influenced by ionic conductivity and bound water relaxations at the lower frequencies and by free water relaxation at the higher end of the frequency range.

Fruit↗
PubMed1994

The expression of proliferation-dependent antigens during the lifespan of normal and progeroid human fibroblasts in culture.

Normal human fibroblasts display a limited lifespan in culture, which is due to a steadily decreasing fraction of cells that are able to proliferate. Using antibodies that react with antigens present in proliferating cells only, in an indirect immunofluorescence assay, we have estimated the fraction of proliferating cells in cultures of normal human fibroblasts. Furthermore, we have estimated the rate of decline in the fraction of proliferating cells during the process of cellular ageing by application of the assay to normal human fibroblasts throughout their lifespan in culture. Werner's Syndrome is an autosomal recessive disease in which individuals display symptoms of ageing prematurely. Werner's Syndrome fibroblasts display a reduced lifespan in culture compared with normal human fibroblasts. Like normal human fibroblasts, the growth of Werner's Syndrome fibroblasts is characterised by a decreasing fraction of cells reacting with the proliferation-associated antibodies throughout their lifespan in culture. However, the rate of loss of proliferating cells in Werner's Syndrome fibroblasts during the process of cellular ageing is accelerated 5- to 6-fold compared with the rate determined for normal human fibroblasts.

Antigens↗
PubMed1994

Essential role of vif in establishing productive HIV-1 infection in peripheral blood T lymphocytes and monocyte/macrophages.

The role of vif during the establishment of human immunodeficiency virus type 1 (HIV-1) infection of peripheral blood T lymphocytes and monocyte/macrophages was investigated using vif mutants of three HIV-1 proviral DNAs. Vif was found to be essential for the establishment of productive HIV-1 infection in peripheral blood T lymphocytes after cell-free infection with HXB2 and DFCI-HD, a vpr-positive, vpu-positive, nef-positive derivative of HXB2. A chimeric HIV-1 provirus in which the T-cell line-tropic env sequences in DFCI-HD were replaced with the macrophagetropic env of the ADA strain was constructed for studies on the role of vif during the establishment of HIV-1 infection in primary monocyte/macrophages. These studies showed that vif is also essential for the initiation of productive HIV-1 infection in primary monocyte/macrophage cultures after cell-free virus transmission. The DFCI-HD-ADA virus was shown to replicate in the CD4+ T-cell line Molt 4 clone 8 but not in other T-cell or monocytic cell lines, as previously shown for another macrophagetropic strain YU-2 (1), suggesting that this cell line may be useful for future studies on at least some macrophagetropic strains of HIV-1. The finding that vif is essential for the establishment of productive HIV-1 infection in primary T lymphocytes and monocyte/macrophages suggests that vif may be required for HIV-1 transmission and disease pathogenesis during natural infections and thus may be a good target for prophylactic or therapeutic intervention.

Cell Line↗
PubMed1993

Detection of proopiomelanocortin-derived antigens in normal and pathologic human skin.

We investigated the presence of proopiomelanocortin (POMC) products in sections of skin from normal subjects and patients with neoplastic and non-neoplastic cutaneous disorders. Antibodies specific against adrenocorticotropin, beta-melanotropin, and beta-endorphin were used for detection and characterization of cell types bearing POMC peptides. POMC products were not observed in sections of normal skin from the corporal (non-scalp) areas (six cases), whereas the hair follicles of scalp skin exhibited positive immunostains that were readily apparent (four cases). POMC products were frequently detected in corporal skin affected by diseases (13 of 26 cases), for example, psoriatic keratinocytes, the inflammatory infiltrate in scarring alopecia, nevocytes, the epithelial cell nests of basal cell carcinoma, and melanoma cells. Further tests were performed in keloids, a primary reactive skin disorder, to evaluate whether POMC accumulation represented a disease-related phenomenon or an expression of normal cutaneous reactivity. POMC products were consistently detected (10 of 11 cases) in the keratinocytes and mononuclear cells at keloid lesions. Thus these observations indicate that POMC products may accumulate locally in lesional skin representing, presumably, a novel cutaneous response to injury. The broad spectrum of POMC products detected suggests that these arise from production in situ (expression of the POMC gene itself) by human skin.

Adrenocorticotropic Hormone↗