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Biomedical subjects

K S Cross

Publications and source records attributed to K S Cross.

17 recordsLinked to original sources
PubMed2001

Preoperative assessment of primary varicose veins: a duplex study of venous incompetence.

OBJECTIVES: we investigated the importance of preoperative duplex scanning in primary uncomplicated varicose vein surgery by evaluating the incidence of superficial venous imcompetence and significant anatomical variations that may be difficult to detect clinically and therefore might be expected to contribute to recurrence. DESIGN: a retrospective study of a prospectively collected database. MATERIALS: over 15 consecutive months, patients attending the non-invasive vascular laboratory for duplex scanning of their primary uncomplicated varicose veins were assessed. METHODS: vascular laboratory case notes were assessed and incidence of superficial venous incompetence and any significant anatomical variations that would have been difficult to detect clinically +/-HHD were documented. Any correlation with clinical findings was also evaluated. RESULTS: a total of 223 limbs (176 patients) were assessed. Sixty-seven limbs (30%) in fact had a competent sapheno-femoral junction. Sixty-one limbs (27%) had pure sapheno-femoral reflux and nil else. Fifty-three limbs (24%) had significant anatomical variations. Forty-two limbs (19%) had short saphenous vein incompetence, of which 67% were clinically unsuspected. CONCLUSIONS: preoperative duplex scanning is indicated in all patients with uncomplicated primary varicose veins if appropriate venous surgery is contemplated. There are obvious resource and recurrence rate implications. Further evaluation in the form of randomised trials are required.

Adolescent↗
PubMed2000

Inflammatory abdominal aortic aneurysms: diagnosis with gadolinium enhanced T1-weighted imaging.

AIM: Inflammatory abdominal aortic aneurysms (IAAA) are a variant of abdominal aortic aneurysms, which are associated with an increased morbidity. The diagnosis of IAAA has traditionally been established with a combination of clinical and laboratory findings together with contrast enhanced CT. There is a high incidence of renal impairment in this group, and therefore contrast enhanced CT may be harmful. PATIENTS AND METHODS: Five patients with IAAA underwent T1-weighted spin echo and gradient echo gadolinium enhanced abdominal MRI. A total of eight examinations were performed, including three patients who underwent repeat MRI following steroid therapy. RESULTS: The inflammatory cuff was clearly identified following gadolinium administration in all eight examinations. The cuff enhanced homogeneously in all patients with no alteration in appearance following steroid therapy. The intravenous administration of gadolinium DTPA enabled clearer definition of locally involved structures. CONCLUSION: Gadolinium enhanced MRI readily demonstrates features of IAAA. In view of potential renal impairment in this patient group, we recommend this technique in preference to contrast enhanced CT in the initial investigation of inflammatory abdominal aortic aneurysms.

Aged↗
PubMed2000

Management of synchronous infrarenal aortic disease and large bowel cancer: a North-east of Scotland experience.

OBJECTIVES: to review our experience of combined aortic and colonic surgery. DESIGN: retrospective review. METHODS: synchronous aortic and colorectal procedures were identified from prospective computerised audit and archival vascular records. Clinical parameters were used as surrogates for measuring clinical outcome. RESULTS: six patients (F:M=2:1), median age 75.6 years (range 70-80 years) were identified with infrarenal aortic pathology (5 aneurysms, median AP diameter 6 cm, 1 occluded aortoiliac segment) and colonic carcinoma. All carcinomas were Dukes stage B and moderately well differentiated. Synchronous aortic and colonic resections were performed in five cases, bypass for aortoiliac occlusion was deferred in preference to colonic resection in one case. Operating time ranged between 3-6.5 hours (median 4 h), transfusion requirements 2-5 units (median 3 units). One anastomotic dehiscence was reported. With follow-up between 6 months to 6 years all patients remain alive; no patient has re-presented with graft sepsis or symptomatic tumour recurrence. CONCLUSION: synchronous resections of aortic and colonic lesion may be a treatment option in selected cases.

Adenocarcinoma↗
PubMed1998

Screening for diabetes on a vascular ward: lessons from an audit.

Owing to the high prevalence of diabetes mellitus in patients with peripheral arterial disease, screening for this disorder is necessary on a vascular ward. Our current practice of random plasma glucose (RPG) testing on every admission was reviewed. This test, although crude, excludes diabetes if the cutoff level is set as low as 6.0 mmol/L. A total of 36% of our patients had an abnormal result, but this was not further acted upon. A further 19% had no test result recorded at all. This practice is inadequate and has resulted in the following implementations: (1) every patient with clinical evidence of arterial disease should have their RPG level measured; (2) patients with a level > 6.0 mmol/L should have a fasting plasma glucose level estimated; and (3) patients with an abnormal fasting plasma glucose level should be referred to the diabetic clinic.

Aged↗
PubMed1994

Long-term human vein graft contractility and morphology: a functional and histopathological study of retrieved coronary vein grafts.

Vasoreactivity of 11 coronary artery vein bypass grafts and 13 human saphenous veins was examined. Isometric tension studies were performed in response to potassium chloride (110 mmol/l), noradrenaline (10(-9)-10(-4) mol/l), serotonin (10(-9)-10(-4) mol/l) and histamine (10(-8)-10(-2) mol/l). After precontraction with noradrenaline (10(-5) mol/l), the response to acetylcholine (10(-8)-10(-4) mol/l) and the calcium ionophore A23187 (10(-8)-10(-4) mol/l) was also assessed. Results are given as mean(s.e.m.). Compared with saphenous veins, vein grafts showed decreased sensitivity to noradrenaline (1.7(0.5) versus 0.4(0.1) mumol/l, P = 0.01), no change in sensitivity to serotonin (55(18) versus 37(15) mumol/l, P > 0.05) and supersensitivity to histamine (3.2(0.9) versus 30.1(13.2) mumol/l, P = 0.01). Vein grafts had a decreased maximal contraction to potassium chloride (1.1(0.3) versus 5.5(0.8) g, P = 0.0001), noradrenaline (1.2(0.3) versus 4.1(0.8) g, P = 0.005), histamine (1.2(0.3) versus 4.5(0.8) g, P = 0.003) and serotonin (0.7(0.2) versus 5.7(0.6) g, P = 0.0002) compared with saphenous vein. Precontracted vein grafts did not relax in response to acetylcholine; in contrast, saphenous vein relaxed in a dose-dependent manner to a maximal relaxation of 22(3) per cent. Both saphenous vein and vein graft relaxed in response to A23187. Vein graft intimal thickness was approximately fourfold greater than that of saphenous vein (540(110) versus 136(30) microns). Scanning electron microscopy of vein and vein graft revealed an intact endothelium. Coronary artery vein grafts are capable of responding to various contractile agonists; these response are notably different from those of saphenous vein and there is a loss of endothelium-dependent relaxation. Even at a late stage vein grafts are not inert but are functional conduits with an abnormally responsive endothelium and a less potent, but significantly altered, smooth muscle contractile profile.

Aged↗
PubMed1994

Improved limb salvage and mobility following peroneal artery bypass.

During the 10-year period August 1981 to 1991, 92 consecutive patients underwent revascularisation to the peroneal artery (40 to the upper third, 30 to the mid and 22 to the distal third). The male/female ratio was 1.6:1 and the mean age was 72 years. Thirteen patients had independent mobility preoperatively while 58 had limited mobility and the remaining 18 were bed/housebound. Following surgery the patients were prospectively evaluated and mean follow-up was 25 months. The 1 and 3 year patency rates were 67 and 59% respectively and cumulative limb salvage rates were 75 and 71%. Forty-four patients returned to independent mobility while 36 had limited mobility and 11 remained housebound. Reconstruction to the peroneal artery is a valuable adjuvant for limb salvage providing satisfactory cumulative patency and facilitating improved mobility.

Aged↗
PubMed1992

Foreign body complications of central venous catheterisation in critically ill patients.

In three critically ill patients, central venous catheter--associated foreign bodies were identified while the patients were in the intensive care unit. Two patients had fragments of retained catheter; in the third patient a guide-wire was lost within the vascular tree. The catheter fragments were associated with clinical symptoms while side effects were not observed with loss of the guide-wire. All three foreign bodies were removed without complications.

Catheterization, Central Venous↗
PubMed1990

Reduction of intimal hyperplasia and enhanced reactivity of experimental vein bypass grafts with verapamil treatment.

Recent studies have shown that calcium antagonists exert an antiatherogenic effect in animals fed cholesterol. Vein graft intimal hyperplasia is believed to be an early event in atherosclerotic lesion formation, which is a significant cause of graft failure. Altered vasoreactivity has also been postulated in the etiology of vein graft failure. Therefore this study examined the effect of verapamil treatment on the development of intimal hyperplasia and the vasoreactivity of experimental vein bypass grafts. The right external jugular vein was grafted into the right carotid artery of 30 male New Zealand white rabbits fed normal rabbit chow. The left external jugular vein was used as the control vein. Fifteen animals received verapamil (1.25 mg/day for 28 days) via the femoral vein by means of an osmotic pump. In 15 control animals the pump contained saline. Plasma verapamil concentration was 50.9 +/- 13.2 ng/mL (x +/- SEM), a dose that showed no effect on either blood pressure, total serum cholesterol, or in vitro platelet aggregation to ADP. Fourteen of fifteen grafts were patent in each group, for a patency rate of 93%. Histologic examination using computer morphometry showed significant reduction of intimal hyperplasia at the proximal, middle, and distal graft segments (p less than 0.05). In addition in vitro isometric tension studies of the vein grafts and control veins showed that verapamil causes enhanced reactivity of both vein grafts and control veins in response to norepinephrine and histamine (p less than 0.05). Reactivity of vein grafts to serotonin was unaltered. While none of the normal veins in the control group responded to serotonin, normal veins treated with verapamil contracted readily in response to serotonin. Endothelial-dependent relaxation to acetylcholine was absent in both control and verapamil-treated vein grafts, while normal veins from both groups responded to the same extent to acetylcholine. Because we could not demonstrate any difference in platelet or endothelium function between untreated and verapamil-treated animals, we examined the direct effect of verapamil on smooth muscle. Verapamil significantly inhibited [3H]-thymidine incorporation into DNA in vascular smooth muscle cells in culture in a dose-dependent manner. Verapamil treatment significantly reduces intimal hyperplasia in experimental vein grafts and inhibits smooth muscle cell proliferation in culture. Furthermore the enhanced reactivity to norepinephrine and histamine in the verapamil-treated vessels has no detrimental effect on the patency rate at 4 weeks. Thus by inhibiting intimal hyperplasia, calcium antagonists may improve the long-term patency of vein bypass grafts.

Animals↗
PubMed1989

Normal endothelial function and decreased vasoreactivity of experimental arterial grafts.

During autogenous vascular grafting endothelial cell damage inevitably occurs. In this study we examined the functional and morphologic integrity of experimental arterial grafts. The right external iliac artery was grafted into the right carotid artery of 12 male New Zealand white rabbits. The left external iliac artery was used as the control artery. Four weeks after surgery, isometric tension studies were performed on rings of control artery and arterial graft. Control arteries and arterial grafts precontracted with norepinephrine demonstrated endothelium-dependent relaxation of 28.3% +/- 5.6% and 16.1% +/- 1.7%, respectively, in response to acetylcholine (5 x 10(-6) mol/L). Both control arteries and arterial grafts contracted in response to norepinephrine, histamine, and serotonin. The median effective dose (ED50) of norepinephrine was 4.1 +/- 1.3 x 10(-7) mol/L for control arteries and 62.1 +/- 17.9 x 10(-7) mol/L for arterial grafts (p less than 0.005). Similarly, arterial grafts were less sensitive to histamine; the ED50 of histamine for control arteries was 4.6 +/- 1.3 x 10(-7) mol/L and 51.4 +/- 13.0 x -7 mol/L for arterial grafts (p less than 0.005). In contrast, reactivity to serotonin was unaltered. The ED50 was 4.1 +/- 1.3 x 10(-7) mol/L for control arteries and 4.5 +/- 1.3 x 10(-7) mol/L for arterial grafts. Scanning and transmission electron microscopy revealed a largely intact endothelial surface. These data are markedly different from our previous findings with vein grafts in which serotonin supersensitivity was associated with an absence of endothelium-mediated relaxation to acetylcholine.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1988

Functional abnormalities of experimental autogenous vein graft neoendothelium.

When a vein is grafted into the arterial circulation, the endothelium of the graft is damaged. Regeneration of an intact neoendothelium occurs, but the functional properties of this surface have not been clarified. In this study, the functional integrity of the neoendothelium of veins grafted into the carotid artery of the rabbit was assessed through the use of acetylcholine and histamine to stimulate the production of the important endothelium-derived relaxing factor (EDRF). Control veins, precontracted with norepinephrine [10(-5) M], relaxed after exposure to acetylcholine [( 10(-7) M], 42.4% +/- 6.4%, p = 0.008) and histamine [( 10(-6) M], 30.6% +/- 4.3%, p = 0.03). This relaxation response was abolished after mechanical removal of the endothelium. By contrast, neither acetylcholine nor histamine caused an endothelium-dependent relaxation in the vein grafts, even though scanning electron microscopy demonstrated the presence of a morphologically intact endothelium. However, addition of stabilized EDRF purified from cultured endothelial cells induced relaxation of the vein grafts (35.8% +/- 3.6%, p = 0.002). These data indicate that vein graft endothelium is unable to produce EDRF in response to exposure to acetylcholine or histamine. The inability to produce this potent smooth muscle cell relaxing factor and anti-aggregatory substance may be a predisposition to vein graft failure.

Acetylcholine↗
PubMed1988

Mast cell infiltration: a possible mechanism for vein graft vasospasm.

Mast cell infiltration of the arterial wall has been demonstrated in atherosclerotic vessels and implicated in coronary artery spasm. Spasm of vein bypass grafts has also been reported. In this study we performed vein bypass grafting of the carotid arteries in rabbits and examined the grafts for the presence of mast cells. We also determined vein graft vasoreactivity to histamine, to assess whether mediators of mast cells may have a functional role in vivo. In the control veins no mast cells were identified in 80 high-power fields (400X). In the vein bypass grafts an average of 2.6 +/- 0.8 (p = 0.01) mast cells were identified in the same number of high-power fields. Isometric tension studies of control vein and vein bypass grafts treated with histamine resulted in sigmoid dose-response curves. The ED50 for control vein was 4.69 +/- 0.63 X 10(-5) mol/L. Compared with control vein, the vein bypass grafts showed a rightward shift in the dose-response curve to histamine (ED50 11.6 +/- 1.7 X 10(-5) mol/L, p = 0.01). The histaminergic response in both vessels was blocked by the H1 receptor antagonist pyrilamine (10(-7) mol/L) and was not altered by the H2 receptor antagonist cimetidine (10(-5) mol/L). The decreased sensitivity of vein bypass grafts to histamine suggests receptor down-regulation and is possibly the result of increased histamine in the vein bypass grafts. The presence of mast cells and histamine receptors, as well as altered histamine sensitivity, in vein bypass grafts suggests that infiltration by these cells may contribute to vein bypass graft vasospasm.

Animals↗
PubMed1987

Small bowel obstruction: a review of 456 cases in a west of Ireland region.

A retrospective study was carried out of 456 patients with small bowel obstruction (SBO). The operative findings of all patients who presented with SBO between 1977 and 1982 were compared and contrasted with those who presented during equivalent periods in the previous three decades. Obstructed hernias still account for the highest percentage of cases. Surprisingly, adhesions as a causative factor are not significantly more common than they were three decades ago, despite the enormous increase in the frequency with which abdominal surgery is now being carried out. The postoperative mortality rate for the period 1977-82 was 14%.

Adolescent↗
PubMedDate not supplied

Abdominal ascites.

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Ascites↗