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Biomedical subjects

D M Baker

Publications and source records attributed to D M Baker.

At least 37 records · Page 2Linked to original sources
PubMed1996

Assessment of wall structure and composition of varicose veins with reference to collagen, elastin and smooth muscle content.

OBJECTIVES: To compare collagen, elastin and smooth muscle contents of varicose and control long saphenous veins. DESIGN: Collagen, elastin and muscle were estimated stereologically using random sampling and histological staining. MATERIALS: Varicose vein samples were collected from nine patients (mean age 52 years, range 34-64 years) undergoing vein stripping, sample sites being saphenofemoral junction and knee. Control samples were taken from five patients (mean age 58 years, range 38-76 years) presenting for femoral-popliteal bypass at equivalent levels. METHODS: Veins were fixed, sectioned transversely, and stained with Picric Acid Sirius Red. Analysis of samples was performed using point and intersection counting on vertically projected images. RESULTS: Using two way analysis of variance tests, varicose saphenous veins had significantly larger wall areas (p < 0.01) and higher amounts of collagen (p < 0.01). Collagen content and wall area were significantly larger proximally compared to distally in both control and varicose veins (p < 0.05) with a higher content of smooth muscle and elastin in varicose veins proximally compared to distally (p < 0.05). There was no difference in wall thickness or elastin content between the two groups. CONCLUSIONS: This suggests that varicose veins are a dynamic response to venous hypertension and are not thin walled structures as previously thought.

Adult↗
PubMed1996

Haemodynamic and metabolic response to endovascular repair of infra-renal aortic aneurysms.

We have examined whether or not endovascular insertion of a bifurcated aorto-iliac graft resulted in greater intraoperative haemodynamic and metabolic stability than that achieved during conventional open graft placement. We studied 20 patients prospectively during surgery for asymptomatic infra-renal aortic aneurysm. All patients received the same anaesthetic technique. Haemodynamic data were collected continuously using indwelling radial artery and pulmonary artery catheters, allowing calculation of mean arterial pressure (MAP), cardiac output (CO) and systemic vascular resistance (SVR). Blood samples were obtained for measurement of serum lactate concentrations. Variables were compared within each group before and after specific critical events, namely occlusion of femoral or aortic blood flow, or both, and sequential reperfusion of each lower limb. Patients undergoing open repair showed significant changes in CO, MAP and SVR related to aortic cross-clamping and lower limb reperfusion, and a significant increase in blood lactate concentration after distal tissue reperfusion. The only significant changes during endovascular repair were a transient increase in SVR secondary to application of the femoral artery clamps, and sequential decreases when each limb was reperfused. Endovascular aneurysm repair imposed significantly less intraoperative haemodynamic and metabolic stress on the patient compared with conventional open surgery.

Aged↗
PubMed1996

Randomized controlled trial of the effect of mannitol on renal reperfusion injury during aortic aneurysm surgery.

The effects of mannitol on renal impairment following infrarenal aortic aneurysm repair were studied. Patients received either mannitol 0.3 g/kg (n = 15) or saline (n = 13) as a rapid intravenous infusion before aortic cross-clamping. One patient in the control group developed fatal postoperative renal failure but there was no renal failure in the mannitol group. Two patients treated with mannitol died from perioperative myocardial infarction. There were no significant differences in postoperative blood urea level, serum creatinine concentration or creatinine clearance between mannitol and control groups. In patients who had mannitol there was a significant diuresis on the first day after operation (mean urine output 2250 ml) compared with before operation (1557 ml) (P = 0.007). Compared with controls, patients treated with mannitol had lower mean (s.e.m.) postoperative levels of urinary albumin (160(32) versus 500(140) mg per mmol creatinine; P = 0.036) and N-acetyl glucosaminidase (143(34) versus 271(70) mumol per mmol creatinine; P = 0.04) indicating a reduced level of subclinical glomerular and renal tubular damage. These data demonstrate that mannitol reduces subclinical renal injury following infrarenal aortic aneurysm repair.

Aged↗
PubMed1995

Superiority of conventional culture technique over rapid detection of group A Streptococcus by optical immunoassay.

An optical immunoassay (OIA) has been reported to be more sensitive than conventional culture for the detection of Group A Streptococcus, eliminating the need for culture. We attempted to confirm the sensitivity and specificity through a laboratory quantitation study and a clinical trial. OIA did not detect Group A Streptococcus below 10(5) colony forming units (CFU). Culture detected Streptococcus to 10(2) CFU from the inoculated swab. In the clinical study, throat swabs were obtained from 77 patients in an outpatient clinic. Compared with culture, the sensitivity of OIA was 78% and the specificity was 90%. These results demonstrate that OIA was less sensitive than culture in seeded experiments and missed 22% of positives in clinical practice. Our study, contrary to previous reports, suggests that OIA is not sensitive enough to be used as the sole assay for Group A Streptococcus pharyngitis.

Adult↗
PubMed1995

How successful is varicose vein surgery? A patient outcome study following varicose vein surgery using the SF-36 Health Assessment Questionnaire.

OBJECTIVE: Assessment of outcome after varicose vein surgery. DESIGN: Prospective study using the Health Assessment Questionnaire (SF36) which considers different aspects of overall health. SETTING: University Hospital and Community. MATERIALS: 150 patients undergoing varicose vein surgery. CHIEF OUTCOME MEASURES: SF36 questionnaires were sent pre-operatively and at 1 and 6 months post surgery. MAIN RESULTS: Eighty-nine (59%) patients answered all three questionnaires. Pre-operatively their overall health was similar to that of the general population. The "cost" to the patient of the operation was demonstrated by an increased pain and reduced role function at 1 month post-operation (p < 0.01). By 6 months post-operation, when compared with preoperative values, all dimensions except social function and health perception were improved (p < 0.01). Overall symptoms improved (p < 0.01) by 1 month and were further improved at 6 months. CONCLUSIONS: The general good health of varicose vein patients may justify the low priority given to their treatment, but the improvement in symptoms and general health that relatively simple surgery provides should ensure its continued provision as a health care service.

Adult↗
PubMed1994

Transfemoral endoluminal repair of abdominal aortic aneurysm with bifurcated graft.

Traditional open repair of abdominal aortic aneurysm has disadvantages. We present our experience of transfemoral endoluminal repair with a bifurcated graft system. 29 patients with aortic aneurysm over 5.5 cm in diameter and 1 with a 3.2 cm aneurysm and bilateral iliac stenosis were assessed; 5 were suitable for the procedure. The operation was successful in all the patients, without haemodynamic compromise or major complications. This technique has the potential to reduce morbidity and mortality from abdominal aortic aneurysm. Further modifications are required to make it applicable to most aneurysms.

Aged↗
PubMed1994

Taurolidine peritoneal lavage as prophylaxis against infection after elective colorectal surgery.

A total of 300 patients undergoing elective colorectal surgery over a 3-year period were randomly assigned to receive intraoperative peritoneal lavage with either taurolidine or saline. Culture swabs were taken from the region of surgery before and after lavage and the development of postoperative infection monitored. Of the positive culture swabs before lavage, a significantly higher proportion were negative after lavage with taurolidine than after that with saline. However, there was no difference in the incidence of postoperative infection between groups, suggesting that taurolidine intraoperative peritoneal lavage confers no clinical benefit over that with saline.

Anti-Infective Agents, Local↗
PubMed1994

Significant plain film findings in sigmoid volvulus.

The aim of this study was to evaluate the plain abdominal radiographs of patients thought clinically to have a sigmoid volvulus. Strict diagnostic criteria based on the findings at barium enema and/or surgery were applied to establish or refute a diagnosis of sigmoid volvulus. The presenting plain abdominal radiographs were assessed for 10 radiological signs considered valuable in the diagnosis of sigmoid volvulus. Of the 17 patients with a volvulus, 88% had 6 or more signs, and in the 5 patients without a volvulus, 80% had 4 signs or less. Five signs achieved significance in differentiating between the groups. Three signs, apex of the loop under the left hemi-diaphragm, inferior convergence on the left and the left flank overlap sign, were 100% specific as well as being highly sensitive. The signs which were least specific were a distended ahaustral sigmoid loop and an air fluid ratio greater than 2:1.

Colon, Sigmoid↗
PubMed1994

When to return to work following a routine inguinal hernia repair: are doctors giving the correct advice?

Recurrence of an inguinal hernia following routine repair is not influenced by the convalescent time off work. Advice on this interval off work should not be influenced by the type of hernia, or the physical content of the patient's occupation. To determine if this is the case a questionnaire was sent to the 32 consultant surgeons and 487 general practitioners in the Nottingham district. They were asked when they advised males between 18 and 65 years of age to return to work following a routine hernia repair and what factors influenced this time interval. The median advised time off work (4-6 weeks) was longer than that proposed by earlier studies (3-4 weeks). The advice of only 4% of doctors was not influenced by other factors. The physical content of the patient's job and whether he was self-employed had most influence on the advice doctors gave on when to return to work. In conclusion most doctors are wrongly advising patients on when to return to work following an inguinal hernia repair.

Absenteeism↗
PubMed1994

The management of acute sigmoid volvulus in Nottingham.

Forty previously undiagnosed cases of acute sigmoid volvulus presenting over five years in Nottingham are retrospectively reviewed. The average age was 71.6 years with an even sex ratio. Fifteen (38%) patients lived in nursing homes or institutions. At presentation, all had clinical features of large bowel obstruction, confirmed on plain abdominal X-ray. Sigmoidoscopy and rectal tube decompression was successful in 23 cases. The remaining 17 patients were treated surgically, within 24 hours, at which time the sigmoid was sutured to the abdominal wall (2 cases), resected and brought out as a colostomy (10 cases) or resected and primarily anastomosed (5 cases). Whilst in hospital, of those treated conservatively five died, and three from those treated surgically, four from those in which a colostomy was formed died and three from those in which a primary anastomosis was fashioned died. Of those that survived 11 from the conservative group had at least one recurrence, but none recurred following surgery. In conclusion, acute sigmoid volvulus affects an old and infirm population and carries a poor prognosis. Conservative management is initially preferable, but if emergency surgery is necessary a colostomy rather than primary anastomosis is indicated.

Acute Disease↗
PubMed1994

Operative lumbar sympathectomy for severe lower limb ischaemia: still a valuable treatment option.

Over a 5-year period, 132 operative lumbar sympathectomies were performed on 118 patients with severe peripheral vascular disease unsuitable for vascular reconstruction. In 62 patients local ulcer débridement or toe amputation was performed at the same time. There was a 45% subsequent limb loss, which occurred predominantly in the first 6 months after sympathectomy. The risk of limb loss was independent of diabetes, hypertension, ischaemic heart disease, cerebrovascular disease or concomitant reconstructive surgery. Of the limbs that survived, rest pain had resolved in 86% within 6 months and 64% recovered from all trophic changes over a similar period. This series suggests that lumbar sympathectomy coupled with local tissue management remains a valuable treatment option for the severely ischaemic limb not amenable to reconstructive surgery.

Adult↗
PubMed1993

Transfected leukocyte integrin CD11b/CD18 (Mac-1) mediates phorbol ester-activated, homotypic cell:cell adherence in the K562 cell line.

The CD11b/CD18 leukocyte integrin molecule mediates diverse neutrophil adherence-related functions, including cell:cell and cell:extracellular matrix attachments. To study the individual role of this leukocyte integrin in cell adherence in hematopoietic cells, we expressed the CD11b/CD18 complex on the surface of K562 cells, a cell line derived from an individual with chronic myelogenous leukemia in blast crisis. We used an amphotrophic retroviral vector designated LCD18SN, harboring the complete coding sequence for the CD18 subunit, to transfer the CD18 cDNA into K562 cells and select stable cell lines. The CD11b subunit in the expression plasmid pREP4 was transfected into these K562/CD18 cells by electroporation and stable cell clones were selected. These K562 cells possessed RNA and intracellular protein for each subunit, and they expressed the CD11b/CD18 heterodimer on the cell surface. When CD11b/CD18 expressing K562 cells were stimulated with phorbol myristate acetate (50 ng/mL) for 24 to 48 hours, these K562 cells formed dense cell:cell aggregates. This homotypic aggregation required both activation of the CD11b/CD18 complex and the induction of the counter-receptor for CD11b/CD18 on the conjugate cell. This cell line will (1) enable the structure-function relationships between cell activation and homotypic adherence to be assessed, (2) provide the opportunity to identify accessory molecules required for activation of the CD11b/CD18 complex, and (3) facilitate the identification of novel ligands for the CD11b/CD18 complex.

Cell Adhesion↗