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Biomedical subjects

H L Thomas

Publications and source records attributed to H L Thomas.

15 recordsLinked to original sources
PubMed2006

Evaluation of the effectiveness and efficiency of the public health management of cases of infection due to Salmonella typhi/paratyphi in North East London.

OBJECTIVES: To evaluate the public health management of cases of Salmonella typhi/paratyphi in North East London in relation to national Public Health Laboratory Service (PHLS) guidelines and to determine the effectiveness and efficiency of current practice. STUDY DESIGN: A retrospective case-note review of laboratory-diagnosed cases of infection due to S. typhi/paratyphi in North East London in the 36 months from January 2002 to June 2004. RESULTS: Eighty-one cases were diagnosed with infection due to S. typhi/paratyphi during the study period. Sixty-seven cases (83%) were notified to the relevant local authority and 38 of these had at least the minimum number of follow-up samples recommended in national guidelines. A total of 251 contacts were screened with between one and six stool samples. One contact was identified who appeared to be a chronic carrier of S. typhi. The cost of identifying one person with a positive stool sample was estimated to be pounds sterling 3463 and the cost of detecting one probable chronic carrier was estimated at pounds sterling 17315. CONCLUSIONS: : There have been considerable difficulties in ensuring that case follow-up and contact screening is carried out according to national guidelines in North East London. Amongst those screened, the detection of excretors of pathogenic organisms was low. No chronic carriers were detected amongst the contacts of cases that acquired their infection abroad. Screening all such contacts is difficult to carry out and appears to be an inefficient use of resources.

Carrier State↗
PubMed2003

Retrospective evaluation of equine prepurchase examinations performed 1991-2000.

REASONS FOR PERFORMING STUDY: Prepurchase examinations of horses are used increasingly as a means of evaluating future soundness. Data is lacking in the literature of the radiographic findings and results of the lameness examination of comprehensive prepurchase examinations. OBJECTIVE: To summarise the clinical and radiographic findings of prepurchase examinations and determine if radiographic findings correlated with the lameness examination and sale outcome. METHODS: Records of 510 cases were reviewed, radiographs evaluated and grades assigned the navicular bone, distal phalanx, and tarsus. Follow-up information on the horse status was obtained by telephone interviews for 173 horses. RESULTS: Thoroughbred geldings represented the most common breed and sex, mean age 8 years, mean asking price 12,439.40 dollars, and 52.8% were lame. Radiography was the most common diagnostic procedure performed (61.6%), with views of the front feet requested most often (86.6%) followed by the tarsi (68.1%). Grade 1 was most common for the navicular bone while Grade 2 predominated for the distal phalanx. The number of sound horses decreased as grades became more severe. For the tarsi, Grades 0 and 1 were most common for the proximal intertarsal and distal intertarsal/metatarsal joints, respectively. Horses with significant tarsal changes were still able to compete at their expected level. With respect to the radiographic examination, the mean +/- s.d. grade of the horses which were not lame at follow-up was 1.2 +/- 0.9 for the navicular bone and 15 +/- 0.8 for the third phalanx. The mean +/- s.d. grade of sound horses for the distal intertarsal joint was 0.7 +/- 0.6 and 1.14 +/- 0.8 for the tarsometatarsal joint. Horses for which owner follow-up was available and which had a Grade 3 score were also evaluated. For the navicular bone, 17/31 with a Grade 3 remained in active use at follow-up and for the distal phalanx 21/27 were in active use. For the distal intertarsal and tarsometatarsal joints, 20/21 with a Grade 3 were still in active use. CONCLUSIONS: Prepurchase examinations can have a significant effect on the outcome of the sale. For the navicular bone and distal phalanx, higher grades were associated with lameness. In contrast, higher grades in the tarsus were less likely to be associated with lameness. Warmbloods tended to have more extensive changes in the navicular bone and distal phalanx relative to Thoroughbreds but were not as lame. POTENTIAL RELEVANCE: Radiographic changes detected in the navicular bone, distal phalanx and tarsus should be interpreted with consideration to the clinical examination.

Age Factors↗
PubMed1999

Radiation exposure to personnel during examination of limbs of horses with a portable hand-held fluoroscopic unit.

OBJECTIVES: To determine radiation exposure to personnel during fluoroscopic imaging of limbs of horses with a portable unit and to determine distance from the c-arm at which radioprotective clothing is not required. DESIGN: Repeated-measures cohort study. SAMPLE POPULATION: Part 1, 1 forelimb and 1 hind limb from each of 5 equine cadavers; parts 2 and 3, personnel involved during imaging of limbs of 5 and 9 horses, respectively. PROCEDURE: Radiation exposure rates were mapped around the suspended c-arm of a portable fluoroscopy unit during imaging of various joints of equine cadaver limbs. During similar examinations in live horses, exposure rates to the fluoroscopist and assistant were measured. Mean duration for fluoroscopy of various joints was determined by observing an experienced fluoroscopist. Exposure to fluoroscopists and assistants per examination and per annum was estimated. RESULTS: Radiation exposure rates were dependent on distance and direction relative to the c-arm and consistently highest on the tube side of the unit. Exposure was significantly greater than background amounts until approximately 4.7 m from the c-arm. During examination of live horses, exposure was highest to the fluoroscopist's hand nearest the tube. Typically, exposure to the fluoroscopist and assistant during carpal examination was 25 to 40 times greater than that for comparable radiographic examination. Annual exposure for fluoroscopists was more than twice the recommended maximum permissible dose. CONCLUSIONS AND CLINICAL RELEVANCE: Fluoroscopic imaging of limbs of horses represents a major source of radiation exposure. Annual maximum permissible doses of radiation will be rapidly exceeded if required radioprotective clothing is not worn.

Animal Technicians↗
PubMed1998

Postcastration eventration in 18 horses: the prognostic indicators for long-term survival (1985-1995).

Castration of horses is considered a common and routine surgical procedure, but the potential for complications is high. By far the most serious of these is eventration. The objectives of this study were to determine the long-term survival of horses undergoing surgical treatment of indirect (1) inguinal eventration of the small intestine following castration, and to identify prognostic indicators for survival. The case records of 18 horses undergoing surgical treatment of postcastration eventration (PCE) between 1985 and 1995 were reviewed. Follow-up information was obtained by telephone interviews 2 to 13 y postoperatively. A Cox proportional hazard regression model was fitted to determine which clinical features were of significant influence to survival. Clinical features with a significant negative influence on survival were an inguinal surgical approach for correction, an increased length of prolapsed bowel, and performance of bowel resection and anastomosis. Significant postoperative complications developed in 89% of cases; 44% of cases in the "inguinal" surgical approach group developed peritonitis, compared with 10% in the "midline" approach group. Of all horses in this study, 72% were discharged from the hospital; however, only 40% of horses in the inguinal approach group were discharged. The long term survival rate (> 1 y) for all horses in this study was 44%, with a median survival time of 3-1/2 mo.

Animals↗
PubMed1997

Multiple aneurysmal bone cysts in a foal.

Multiple aneurysmal bone cysts (ABCs) are previously unreported in horses. An ABC was diagnosed in the left 3rd metacarpal of a Thoroughbred foal, which partially resolved following surgical curettage. A 2nd ABC developed in the left tibia, 7 wk postoperatively, and the foal was euthanized.

Animals↗
PubMed1986

An analysis of possible prognostic features of long term and short term survivors of metastatic breast cancer.

Factors influencing the extremes of survival in disseminated breast cancer were analysed. From a pool of 1066 patients with distant metastatic breast cancer, the 41 patients who had survived 5 yr or more from first distant recurrence were matched with the 41 patients with the shortest survival times. Both groups were compared with the pool and, where relevant, with each other. There were no differences with respect to presentation clinical stage, histological subtype, adjuvant therapy or the likelihood of menopause during the disease-free interval. There were significant differences in age, menopausal status, primary treatment, grade, pathological node involvement, time to recurrence, situation and number of sites of metastatic involvement, and response to treatment. The interpretation of these relationships as causal or casual is uncertain; however, given the magnitude of the survival differences, we expected the associated differences to be much greater than we found.

Adult↗
PubMed1978

Ex vivo removal of serum IgG in a patient with colon carcinoma: some biochemical, immunological and histological observations.

Plasma of a patient with metastatic colon carcinoma was perfused over Formalin and heat-killed S. aureus, in an extracorporeal filtration apparatus, in order to nonspecifically remove IgG and its complexes. Twenty ex vivo absorption procedures were done, over a five-month period, with a minimum of discomfort to the patient. Extracorporeal perfusion of plasma on S. aureus effectively reduced the levels of IgG and immune complexes in the perfused plasma. The nonspecific removal of IgG resulted in 1) slight biochemical alterations in the serum, 2) a transient reduction in the serum blocking activity and appearance of complement-dependent serum cytotoxicity, 3) an increase in the serum IgM levels, 4) a transient increase in the Ig surface-bearing lymphocytes and a decrease in "E" rosetting lymphocytes in the first 24-48 hours postperfusion, particularly during the early treatments, 5) an improvement in general condition of the patient and decrease in tumor size, and 6) histological changes in the tumor consistent with tumor destruction. The potential problems and clinical applications of procedures involving ex vivo specific or nonspecific immunoabsorbents are discussed.

Adenocarcinoma↗
PubMedDate not supplied

Innovations in the design and performance of underpads for patients with burns.

The purpose of this study was to determine the biomechanical performance of commercially available underpads and bed linens to reduce the development of pressure sores in patients with burns who are at high risk. The three biomechanical performance parameters examined were coefficient of friction, absorbent capacity, and rewet. Because wetting either cotton or cotton/polyester bedsheets markedly increases their coefficients of friction, underpads should be used routinely to protect the skin against frictional forces. One disposable underpad is ideally suited to protect the skin of the patient at high risk. It has a polyolefin backing with a low coefficient of friction that serves as an effective barrier to moisture transmission while still shifting easily with the patient's movement. In addition, it is the only underpad studied that contains a superabsorbent polymer that provides a far superior absorbent capacity and minimizes rewet. Wet-back is further inhibited by its thick intermediate tissue layer and its spunbonded polypropylene coverstock.

Absorption↗
PubMedDate not supplied

Recent advances in absorbent products for the incontinent patient with burns.

The purpose of this study is to describe the physical configuration of disposable and reusable absorbent products and relate composition and construction to efficacy in the management of urinary incontinence in patients with burn injuries. The basic structure of a wearable absorbent product consists of three layers: a fluid-impermeable backing sheet, a fluid-pervious coverstock on the body-contacting surface, and an interposed absorbent core. The biomechanical performance of these absorbent products was determined by measuring the total absorbent capacity, defined as the maximum amount of liquid held by the product as a whole. On the basis of the results of this study, absorbent products are recommended for the incontinent patient with burns.

Burns↗