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Biomedical subjects

J F Chester

Publications and source records attributed to J F Chester.

At least 19 recordsLinked to original sources
PubMed1992

Improved technique for polytetrafluoroethylene bypass grafting: long-term results using anastomotic vein patches.

Results of peripheral arterial bypass using polytetrafluoroethylene grafts have remained poor in comparison with those using saphenous vein grafts, particularly for anastomoses to tibial and peroneal vessels. A simple modification to the conventional operative technique, involving the incorporation of a vein patch into the distal anastomosis, has enabled considerable improvement. Five-year patency rates of 71 per cent for popliteal and 54 per cent for infrapopliteal grafts have been achieved in a series of 256 patients operated on between 1982 and 1989.

Aged↗
PubMed1992

Accelerated thrombolysis using pulsed intra-thrombus recombinant human tissue type plasminogen activator (rt-PA).

The efficacy of regional thrombolysis for treating leg ischaemia is well established, but the duration of infusion and the frequent complications remain major disadvantages. By delivering recombinant human tissue type plasminogen activator (rt-PA) as pulsed intra-thrombus 5-mg aliquots combined with catheter manipulation to maintain an intra-thrombus location, the average time taken to achieve thrombolysis in 20 consecutive patients with infra-aortic occlusions was 109 min. Immediate thrombolysis was achieved in every case. Pulsed delivery of high dose rt-PA significantly accelerates thrombolysis, decreases dose and reduces costs.

Adult↗
PubMed1992

Vascular reconstruction at the groin: oblique or vertical incisions?

Incisions for vascular access at the groin are usually vertical. Because such incisions cross the moist skin-crease area and disrupt lymphatics, they may be more prone to infection than oblique incisions placed above and parallel to the groin crease. To determine whether this was the case, 149 patients undergoing vascular reconstruction through a groin incision over a period of 30 months were studied. Those with previous groin incisions were excluded, and where an incision was necessary in both groins, each wound was studied separately. Over a 10-day postoperative period 5 of 85 vertical wounds developed infection with purulent discharge, whereas no oblique wounds (n = 82) became infected (P = 0.032). Oblique incisions for vascular access at the groin are associated with a decreased incidence of wound infection compared with conventional vertical incisions.

Adult↗
PubMed1990

Analgesic benefit of locally injected bupivacaine after hemorrhoidectomy.

The analgesic efficacy of locally injected bupivacaine was studied in 40 patients undergoing hemorrhoidectomy. After a standard Milligan-Morgan hemorrhoidectomy, 40 age- and sex-matched patients were randomized to receive either 0.5 percent bupivacaine (1.5 mg/kg) in adrenaline solution (1:200,000) injected into the perianal area, or equivalent volumes of adrenaline solution. Intramuscular opiate was available on demand during the postoperative period, and the amount and timing of analgesia given was recorded. All patients noted their pain on a daily basis using a linear analogue scale, and all patients answered a questionnaire assessing analgesic efficacy. Although the median time interval between surgery and first analgesic demand was nearly four times greater for patients receiving bupivacaine compared with adrenaline solution, there was no difference in the levels of pain recorded or in the overall opiate requirements. Local injection of bupivacaine after hemorrhoidectomy provides initial pain relief, but patients do not obtain an overall analgesic benefit.

Adult↗
PubMed1990

Experimental evidence to support the use of interposition vein collars/patches in distal PTFE anastomoses.

We have conducted three in vitro experiments (using cadaver internal mammary artery as a model for crural artery), which establish the advantage of the Miller collar and Taylor patch over direct PTFE-artery anastomoses: (1) A new method of simultaneously measuring longitudinal and circumferential elasticity in human saphenous vein (n = 16) has demonstrated the latter to be anisotropic (i.e.: greater longitudinal than transverse compliance, P less than 0.002). This suggests that benefit may be gained by aligning the saphenous vein's longitudinal axis with that of the arteriotomy--a feature of both vein interposition anastomoses. (2) We have compared maximal pulsatile and constant flow across each type of anastomosis (n = 10 of each) using a flow model incorporating standard pressure, viscosity, graft and outflow vessel length, and anastomotic angle. This experiment has demonstrated loss of anastomotic reliability only in direct PTFE-artery anastomoses (i.e. no correlation between flow and vessel diameter, r = 0.04). (3) Casts of the internal anatomy of the anastomoses (n = 10 of each) have demonstrated a greater degree of oval distortion of the toe of the outflow vessel of direct PTFE-artery anastomoses than either of the other techniques (P less than 0.01). This experimental evidence suggests that both of these vein interposition techniques optimise the mechanical properties of saphenous vein and protect small arteries from anastomotic distortion. These benefits do not occur with direct PTFE-artery anastomoses.

Anastomosis, Surgical↗
PubMed1990

Surgical palliation for pancreatic cancer: will biliary bypass alone suffice?

Because a number of options are available to relieve the obstructed bile duct, stomach or both in patients with irresectable carcinoma of the pancreatic head, palliative surgery for this condition was reviewed retrospectively between 1971 and 1981 at the Royal United Hospital, Bath. One hundred and sixty-five patients underwent a biliary bypass procedure with (n = 37), or without (n = 128) gastric drainage. Thirty patients had a prophylactic gastroenterostomy to avoid gastric outlet obstruction: tumour encroachment made gastroenterostomy essential in seven others. After biliary bypass alone, operative mortality was 14%. After a concomitant gastroenterostomy, mortality was 27% (P less than 0.04). Within a year of biliary bypass alone, there was a 9% incidence of gastric outlet obstruction requiring gastric drainage, with an associated mortality rate of 18%. Survival after biliary bypass or biliary bypass with gastroenterostomy was equal (7-8 months). Except where gastric outlet obstruction is imminent, palliation for irresectable pancreatic head carcinomas should be by biliary bypass alone, because the addition of a gastroenterostomy almost doubles the mortality without any advantage in survival time.

Adenocarcinoma↗
PubMed1990

Meatal strictures after transurethral prostatectomy using latex or polyvinyl chloride three-way catheters.

Because latex rubber catheters have been implicated in urethral stricture formation, the incidence of urethral strictures following transurethral prostatectomy (TUP) and subsequent catheterisation with latex rubber or polyvinyl chloride catheters was compared. A total of 84 patients with benign prostatic hyperplasia (n = 71) or prostatic carcinoma (n = 13) underwent assessment of urethral diameter and subsequent internal urethrotomy prior to TUP. Following resection, 42 patients received three-way self-retaining latex rubber catheters and 42 received similar catheters made of PVC. Catheters were removed when the urine was clear (mean time = 3 days), and no patient required recatheterisation. Urinary flow was assessed in all patients at 6, 12 and 24 weeks after surgery, and diminution of flow with submeatal stricture formation was noted in one patient who had received a latex rubber catheter, and in one who had received a PVC catheter. In this study, the composition of the catheter had no bearing on subsequent stricture formation following TUP.

Aged↗
PubMed1989

Experimental pancreatic cancer in the Syrian hamster: effect of cholecystectomy.

Because cholecystectomy stimulates hypertrophy and hyperplasia in the hamster pancreas, its effect on experimental pancreatic carcinogenesis was studied in this animal model. Forty female Syrian hamsters underwent cholecystectomy, while 40 others underwent sham operations. Two weeks later, 30 hamsters undergoing cholecystectomy and 30 hamsters undergoing sham operations received 4 weekly subcutaneous injections of N-nitroso-bis (2-oxopropyl) amine (BOP) (10 mg/kg). Remaining hamsters (n = 20) received equal volumes of 0.9% saline solution. A further 10 hamsters (controls) underwent no surgery and received no injections. Thirty weeks after the first BOP or saline injection the pancreas of hamsters that had undergone cholecystectomy was only 3% heavier than that of sham-operated animals, and there was no difference in the incidence of pancreatic cancer between BOP-treated hamsters that had undergone cholecystectomy and those that had undergone sham operations. In this study, cholecystectomy had no influence on BOP-induced pancreatic carcinogenesis in the Syrian hamster.

Animals↗
PubMed1989

Wound perfusion with bupivacaine: objective evidence for efficacy in postoperative pain relief.

Conflicting reports exist for the efficacy of intermittent wound perfusion with bupivacaine in the relief of postoperative pain. A study was devised to assess postoperative pain relief objectively using a Patient Controlled Analgesic Device (PCAD) during continuous wound perfusion with bupivacaine or saline. Thirty consecutive patients undergoing cholecystectomy were randomised to receive continuous postoperative wound perfusion with 0.5% bupivacaine for 24 h followed by normal saline for a further 24 h or vice versa. During the study period, conventional analgesia was provided using a PCAD set to deliver (and record the number of) on-demand bolus doses of intravenous pethidine 0.2 mg/kg at half-hourly intervals as required. Pethidine requirements were higher on the first postoperative day, regardless of which solution was given, but bupivacaine perfusion almost halved mean linear analogue pain scores compared to those recorded with saline. Likewise, the number of bolus doses of pethidine demanded was reduced by an average of 68% compared to those recorded during saline perfusion on day 1 (P = 0.01) and by 82% on day 2 (P = 0.01). When assessed by objective criteria, perfusion of surgical wounds with bupivacaine after cholecystectomy produces better pain relief than wound perfusion with saline.

Administration, Topical↗