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Biomedical subjects

M A Barraclough

Publications and source records attributed to M A Barraclough.

At least 19 recordsLinked to original sources
PubMed1979

Vipoma of the pancreas: observations on the diarhrhea and circulatory disturbances.

A patient with a vipoma of the pancreas and persistently elevated blood levels of vasoactive intestinal polypeptide (VIP) had watery diarrhea, hypokalemia, and achlorhydria (WDHA syndrome). In the untreated state, the diarrhea was never profuse. Fecal volumes ranged from 0.16 to 1.24 L/day. Attempts to correct the dehydration by fluid and electrolyte loading resulted in a massive increase in fecal water and electrolyte loss. Prednisone cured the diarrhea and was associated with a decrease in plasma VIP levels. The patient had a marked circulatory disturbance with systemic arterial hypotension and cutaneous vasodilation that caused a subnormal body temperature. Removal of the tumor led to a dramatic change in the patient's circulation. Generalized vasodilation with systemic venous and arterial hypotension gave away to vasoconstriction with severe venous and arterial hypertension. Central venous pressure rose from -4.4 to +4.0 cm H2O and arterial pressure rose from 80/55 to 195/110 mm Hg. These changes might explain the unexpected and sometimes fatal heart failure that has complicated the removal of these tumors from some patients.

Achlorhydria↗
PubMed1975

Potassium depletion induced by vasopressin and overhydration in the rabbit.

1. In order to study the effect of overhydration on body potassium, experiments were performed on pair-fed rabbits, one of which was maintained continuously on vasopressin and given extra water (60-90 ml day-1 kg-1) for 6-8 days, while the other served as control. 2. Overhydrated rabbits excreted significantly more potassium (53%) in their urine than control rabbits and accumulated a mean potassium deficit of 65-0 mmol, significantly higher than the mean value of 37-1 mmol in the control rabbits. 3. In the overhydrated rabbits, potassium fell significantly in both erythrocytes, from 266 to 173 mmol/kg of dry cells, and also in muscle, from 435 to 341 mmol/kg of fat-free dry solids. Neither changed significantly in the control animals. 4. Overhydration in the presence of vasopressin leads to potassium depletion in the rabbit and a similar phenomenon might be expected in man. Potassium depletion due to overhydration might account for the hypokalaemia and reduction in exchangeable potassium observed in some patients with the syndrome of inappropriate secretion of antidiuretic hormone.

Animals↗
PubMed1973

Ureteric stricture with analgesic nephropathy.

Three patients with analgesic nephropathy are reported who, in addition to the accepted features of this syndrome, had dilatation of one or both upper urinary tracts due to ureteric or periureteric fibrosis without intraluminal obstruction. We attribute this lesion to analgesic abuse and suggest that any patient with unexplained ureteric fibrosis should be questioned about analgesic consumption. This association also suggests a possible role for analgesic abuse in the pathogenesis of retroperitoneal fibrosis.

Adult↗
PubMed1971

Urine concentration during solute diuresis in potassium-depleted rabbits. Evidence for a defect in tubular sodium transport.

1. The relationship between osmolal clearance (C(osm)) and the reabsorption of solute-free water by the kidney (T(H2O) (c)) was examined during 10% mannitol and 2.3% saline diuresis in normal and potassium-depleted rabbits.2. In normal rabbits at osmolal clearances close to 3.0 ml./min, T(H2O) (c) during mannitol diuresis was 0.87 +/- 0.06 ml./min and during saline diuresis 1.19 +/- 0.07 ml./min. The mean difference in T(H2O) (c) of 0.32 +/- 0.05 ml./min was highly significant (P < 0.001).3. In one group of potassium-depleted rabbits with a reduction in maximal urinary concentration, T(H2O) (c) during both mannitol and saline diureses was reduced significantly below normal and the increment in T(H2O) (c) normally seen during saline diuresis was abolished.4. In a second group of potassium-depleted rabbits maximal urinary concentration (1253 +/- 88 m-osmole/kg H(2)O) was not significantly different from that in normal rabbits (1272 +/- 116 m-osmole/kg H(2)O). In these animals, T(H2O) (c) at osmolal clearances close to 3.0 ml./min was not significantly different during mannitol diuresis (0.83 +/- 0.07 ml./min) from that in normal animals, whereas it was reduced significantly during saline diuresis (0.89 +/- 0.07 ml./min, P < 0.001) and the difference in T(H2O) (c) normally seen between mannitol and saline diuresis was abolished.5. The inability to increase T(H2O) (c) during saline diuresis above that achieved during mannitol appears to be the earliest manifestation of the concentrating defect associated with potassium depletion. It probably results from an impairment of sodium transport by the ascending limb of the loop of Henle. This is supported by the fact that potassium-depleted rabbits excreted a greater percentage of the filtered load of sodium than did normal controls.

Animals↗
PubMed1970

Effects of adenosine 3',5'-monophosphate on renal function in the rabbit.

1. Intravenous injections of adenosine 3',5'-monophosphate (cyclic-AMP) were given to five conscious, diuretic rabbits, and the effects on urinary flow and composition were compared with those of intravenous injections of vasopressin given to the same animals.2. Cyclic-AMP produced antidiuresis with increases in urinary osmolality and in the urinary concentrations of creatinine, urea and usually of sodium.3. The fractional reabsorption of urea from renal tubular fluid increased during cyclic-AMP induced antidiuresis.4. The effects of cyclic-AMP thus closely resembled those of vasopressin and are consistent with the view that cyclic-AMP mediates the action of this hormone.

Adenine Nucleotides↗