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Biomedical subjects

J N Simson

Publications and source records attributed to J N Simson.

At least 19 recordsLinked to original sources
PubMed1988

A new cuffed oesophageal prosthesis for the management of malignant oesophago-respiratory fistula.

Malignant oesophago-respiratory fistula is an incurable and distressing condition. Surgery is difficult, unsatisfactory or impossible, and standard oesophageal tubes often fail to occlude the fistula. A new tube is described which relieves dysphagia and occludes the fistula without risk of pressure necrosis. After insertion of the tube, the patients may be treated by radiotherapy.

Bronchial Fistula↗
PubMed1987

Late rupture of ligated common iliac arteries.

Late rupture may follow simple ligation of the common iliac arteries after aortobifemoral grafting. Oversewing the origins of the arteries may prevent this rare but dangerous complication. A CT scan is recommended to investigate unexplained abdominal pain following aortic surgery.

Aged↗
PubMed1986

Anteroposterior rectopexy in the treatment of solitary rectal ulcer syndrome without overt rectal prolapse.

There is evidence that the solitary rectal ulcer syndrome is associated with rectal prolapse either overt or internal. The anterior rectal wall is affected in most cases and a modified abdominal rectopexy has been used with the aim of supporting both the anterior and posterior aspects of the rectum. Fourteen patients aged 19-70 years (mean 34.2 years) in whom conservative treatment has failed, have been treated by anteroposterior rectopexy. Tenesmus, bleeding and the passage of mucus have been abolished or greatly improved in 12, 14 and 13 patients respectively. The number of attempts to defaecate per 24 h has fallen from 8.7 +/- 1.4(s.e.m.) pre-operatively to 3.4 +/- 1.0(s.e.m.) postoperatively (P less than 0.05) and the time spent in the lavatory has been reduced from 146 +/- 18(s.e.m.) min to 15 +/- 3(s.e.m.) min. Two patients have developed severe constipation postoperatively and two others have had persistent or recurrent tenesmus. Combined anteroposterior rectopexy has improved 12 out of 14 patients with the solitary ulcer syndrome without external rectal prolapse when assessed at 2-48 months postoperatively.

Adult↗
PubMed1985

Congenital diaphragmatic hernia: a 20 year experience.

The records of 253 children with congenital diaphragmatic hernia admitted to The Hospital for Sick Children, Great Ormond Street, between 1961 and 1980 were analysed. The overall mortality of 37 per cent is greater than that reported in the preceding 13 years from the same institution, and showed no improvement over the 20 years. While there was no significant increase in the number of admissions over the study period, the proportion of children who underwent surgery within the first 6 h of life steadily increased from 13 per cent in the first five years to 39 per cent in the last five years. The mortality of this group (65 per cent) did not improve over the study period and this would account for the lack of improvement in the overall survival figures. However, analysis of birth weights, onset and severity of signs and lung weights indicates that the increasing number of early admissions was due to speedier transfer rather than to referral of more severely affected children in the later years.

Child↗
PubMed1985

Temporary antimesenteric stomas without a skin bridge in infants.

Thirty-four loop stomas without a tissue bridge were created in 33 infants. Whenever possible, the antimesenteric stoma was fashioned in the laparotomy wound. When a separate incision was used, the lack of a skin bridge resulted in a more cosmetically acceptable scar after closure of the stoma. Complications associated with such stomas and their closure were no greater than for the conventional loop stomas formed over a tissue bridge.

Cecum↗
PubMed1981

Alkaline secretion by amphibian duodenum. I. General characteristics.

Stripped, proximal bullfrog duodenum was mounted in an Ussing chamber between HCO3--buffered nutrient (serosal) and unbuffered secretory (luminal) solutions. This preparation showed stable electrical parameters and caused alkalinization of the secretory solution at a rate of 0.95 +/- 0.03 mueq.cm-2.h-1 (mean +/- SE; n = 100). Anoxia and 2,4-dinitrophenol each reduced alkalinization by 50-60%, but acetazolamide (5 X 10(-4)M) had no effect. Removal of nutrient HCO3- and CO2 reduced alkalinization by over 90%, whereas increasing nutrient [HCO3-] at constant partial pressure of CO2 (PCO2) or increasing nutrient PCO2 at constant [HCO3-] each caused saturable increases in alkalinization, despite opposite effects on nutrient pH. Dibutyryl adenosine 3',5'-cyclic monophosphoric acid, but not dibutyryl guanosine 3',5'-cyclic monophosphoric acid, increased luminal alkalinization to 167 +/- 21% of control. Removal of nutrient, but not secretory, Na+ reduced alkalinization by 74%. Changes in the rate of alkalinization were accompanied by corresponding changes in potential difference and short-circuit current. Removal of Cl- or nutrient K+ or addition of histamine, thiocyanate, or catecholamines had no effect on electrical or secretory characteristics. We conclude that a) the amphibian duodenum transports alkali from nutrient to secretory solutions by both active and passive processes, b) there is a small secretion of endogenous HCO3-, c) alkaline secretion is electrogenic, d) Cl- does not contribute to the short-circuit current, e) alkaline secretion is partially dependent on nutrient Na+ that acts in a facilitatory, not cotransport, role, f) there is no Cl--HCO3- exchange, and g) alkaline secretion is independent of nutrient pH.

Acid-Base Equilibrium↗
PubMed1981

Alkaline secretion by amphibian duodenum. II. Short-circuit current and Na+ and Cl- fluxes.

The relations among alkaline secretion, short-circuit current (Isc), and fluxes of Na+ and Cl- are examined. The Isc (1.15 +/- 0.03 microeq.cm-2.h-1) was significantly greater than the rate of alkaline secretion (1.02 +/- 0.02 microeq.cm-2.h-1). Regression analysis (n = 300) showed a highly significant correlation between alkaline secretion and Isc and indicated a residual Isc of 0.26 microeq.cm-2.h-1. In the absence of HCO3-, there was a residual Isc of 0.25 +/- 0.04 microeq.cm-2.h-1. This residual Isc is accounted for by an observed net Na+ absorption of 0.28 +/- 0.04 microeq.cm-2.h-1. Fluxes of Na+ fail to fit the flux-ratio equation and were not significantly affected by 2 X 10(-6) M ouabain, 5 X 10(-5) M amiloride, or anoxia but were significantly reduced by 2,4,6-triaminopyrimidine. The net Cl- flux was not significantly different from zero. Cl- fluxes conform to the flux-ratio equation and were reduced by anoxia or 2,4,6-triaminopyrimidine but were not affected by 4-acetamido-4'-isothiocynostilbene-2,2'-disulfonic acid (SITS). Anoxia or ouabain significantly inhibited alkaline secretion and Isc without affecting net fluxes of Na+ or Cl-, whereas amiloride or SITS had no effect on any of these parameters. There is no NaCl-coupled transport nor anion exchange, but solute-coupled Na+ absorption is demonstrated. We conclude that alkaline secretion by the duodenum involves a transcellular, energy-requiring, Na+-dependent, ouabain-sensitive, electrogenic mechanism that accounts for at least 80% of the Isc. Net Na+ absorption accounts for the residual Isc. Movements of Cl- are passive, do not contribute to Isc, and are not involved in the mechanism of alkaline secretion. Two hypothetical models of transcellular alkaline secretion are proposed.

Amiloride↗