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Biomedical subjects

J M Howard

Publications and source records attributed to J M Howard.

At least 91 records · Page 5Linked to original sources
PubMed1989

Delayed débridement and external drainage of massive pancreatic or peripancreatic necrosis.

Thirty-six consecutive patients with massive tissue necrosis resulting from acute pancreatitis were initially managed nonoperatively. In each instance, a mass of necrotic tissue, bathed in fluid, became evident. Laparotomy was delayed unless a life-threatening complication developed. In no instance did the "cavitary necrosis" disappear prior to laparotomy. In five patients, laparotomy was avoided and a chronic pseudocyst evolved. Thirty-one patients required laparotomy, usually after a lapse of one to two months. The necrotic tissue was always retroperitoneal and was clearly demarcated from viable tissue. In most instances, the necrotic tissue was predominantly retroperitoneal adipose tissue. Under such conditions, the anatomic definition of the pancreas, per se, was not practical. The preoperative and operative diagnosis of secondary infection of the necrotic tissue was often difficult. The operation consisted of necrosectomy (débridement) and external drainage. The amount of necrotic tissue was often in excess of 1 kilogram. When necrosectomy was incomplete, secondary explorations and débridement were sometimes necessary. In retrospect, in only a few instances did necrosis and necrosectomy appear to have resulted in the loss of an appreciable amount of pancreatic tissue. One of the 36 patients died, giving a mortality rate that compares favorably with reports of earlier operative intervention.

Acute Disease↗
PubMed1988

Prospective study of chemotherapy in patients with metastatic gastrinoma.

Ten consecutive patients with metastatic gastrinoma that increased in size over time were studied prospectively during treatment with monthly cycles of streptozotocin (3 g/m2), 5-fluorouracil (1.2 g/m2), and adriamycin (40 mg/m2) to determine the response rate and time-courses of changes during chemotherapy and to assess various methods of evaluating the effect of chemotherapy. Forty percent of patients demonstrated an initial objective response (greater than or equal to 25% decrease in tumor size with no new lesions) and 60% failed chemotherapy (greater than or equal to 25% increase in tumor size or appearance of new lesions). The mean dose of streptozotocin was 27 g/m2 with objective responses occurring at 3.7 +/- 0.7 mo and failures at 4.5 +/- 0.7 mo. Responses lasted 9.7 +/- 2.8 cycles and no complete responses occurred. Survival was not significantly different in responders versus nonresponders (26 +/- 11 vs. 15 +/- 4.8 mo, p greater than 0.1). Changes in serum gastrin concentration, basal acid output, or sensitivity to a given dose of histamine H2-receptor antagonist did not reflect changes in tumor size. Computed tomography and angiography were the best methods to assess changes in tumor size during chemotherapy, whereas liver-spleen scan and ultrasound were relatively insensitive. All patients developed side effects with chemotherapy: 100% had vomiting, 80% alopecia, 40% transient proteinuria, and 20% leukopenia. The present results indicate that chemotherapy with streptozotocin, 5-fluorouracil, and adriamycin is much less effective in patients with extensive metastatic gastrinoma than previously reported. Computed tomography scanning is the method of choice to assess changes in tumor size. Changes in serum gastrin concentration, acid secretion, or tumor size assessed by liver-spleen scan or ultrasound are not sensitive indicators of the tumor response during chemotherapy.

Adult↗
PubMed1987

The career paths of nursing graduates from Chelsea College, University of London.

This study aimed to identify the career paths and future career plans of nursing graduates from Chelsea College, University of London. Self-completion questionnaires were sent to the 1981, 1982 and 1983 graduates (N = 54). Employment patterns immediately after and 1, 2 and 3 yr after graduation are described. Most graduates selected careers in nursing, up to 3 yr after graduation. Hospital based clinical posts were most popular and many undertook further clinical courses. The long- and short-term career plans of graduates employed as nurses and those no longer nursing are described. Most graduates indicated that they intended to remain in nursing in the long term.

Career Mobility↗
PubMed1987

Famotidine: effective treatment of Zollinger-Ellison syndrome.

The ability of famotidine to control gastric acid hypersecretion in 32 patients with Zollinger-Ellison syndrome was compared to that of cimetidine or ranitidine. Equipotent doses of each drug were determined in nine patients and famotidine was nine times more potent than ranitidine and 32 times as potent as cimetidine. Famotidine had a 30% longer duration of action than either ranitidine or cimetidine. The 32 patients were treated with famotidine for a mean follow-up of 10.5 months. No hematologic, biochemical, or clinical toxicity occurred. Famotidine appears to be the histamine H2-receptor antagonist of choice in the treatment of Zollinger-Ellison syndrome.

Adult↗
PubMed1986

Famotidine in the therapy of gastric hypersecretory states.

The histamine (H2)-receptor antagonist famotidine was compared with ranitidine and cimetidine in its ability to control gastric acid hypersecretion in 33 patients with gastric hypersecretory states (32 patients with Zollinger-Ellison syndrome and one patient with idiopathic hypersecretion). Equipotent doses of each drug were determined in nine patients and used to determine relative onset of action, duration of action, and potency. Each drug had a similar time course of onset with a maximal effect at three to four hours after oral ingestion. The duration of action of famotidine was 30 percent longer than that of either cimetidine or ranitidine. In terms of relative potency, famotidine was nine times more potent than ranitidine and 32 times more potent than cimetidine. Thirty-two patients underwent long-term famotidine treatment for up to 34 months (mean, 10 months) with a duration in 21 patients of at least six months, in nine patients of at least 12 months, and in six patients of at least 24 months. The mean daily maintenance dose with famotidine was 0.33 g per day (range, 0.05 to 0.8 g). Prior to famotidine therapy, 27 patients were taking ranitidine and the mean daily dose required was 2.3 g per day (range, 0.6 to 5.4 g), whereas six patients were taking cimetidine and the mean daily dose was 4.6 g per day (range, 1.2 to 9.0 g). Fourteen of the 32 patients required an anticholinergic agent in addition to ranitidine or cimetidine to maintain control, whereas only five patients required an anticholinergic agent with famotidine. Gastric acid hypersecretion was controlled in seven patients with less frequent dosing with famotidine than with cimetidine or ranitidine. Long-term treatment with famotidine was not associated with any hematologic or biochemical toxicity or clinical side effects. These results demonstrate that famotidine has a similar onset of action to other H2-receptor antagonists but has a 30 percent longer duration of action and is nine times more potent than ranitidine and 32 times more potent than cimetidine. Famotidine is safe and highly effective in the long-term treatment of gastric hypersecretory states.

Adult↗
PubMed1986

Intraluminal duodenal diverticulum: an unusual cause of acute pancreatitis.

In a series of over 1,000 patients with pancreatitis treated by the senior author, few among the younger patients had a clearly definable cause which permitted cure. Two teenage patients are described in whom an intraduodenal hollow polyp or sac-like diverticulum at the level of the ampulla of Vater was associated with acute pancreatitis. Subtotal resection of the diverticulum provided excellent results. Recognition of the entity and its anatomic relationships to the ampulla of Vater is essential to the prevention of an iatrogenic catastrophe.

Acute Disease↗
PubMed1985

Pseudohyponatremia in acute hyperlipemic pancreatitis. A potential pitfall in therapy.

Six patients had apparent hyponatremia associated with hyperlipidemia and acute pancreatitis. To our knowledge, only one such patient with acute pancreatitis has previously been described, although the association of hyperlipidemia with "pseudohyponatremia" had been well documented. One of the above patients, whose condition was hemodynamically unstable on admission, developed dangerous symptoms of hyperosmolarity and cerebral dysfunction following aggressive resuscitation with hypertonic saline solution. The pseudohyponatremia results from displacement of water in the serum by the lipids, with sodium existing only in the aqueous phase. This volume displacement results in errors of sodium measurement when the latter is determined by flame photometry or indirect potentiometry, but not when determined by ultracentrifugation and direct potentiometry.

Acute Disease↗
PubMed1985

Omeprazole: effective, convenient therapy for Zollinger-Ellison syndrome.

The acute and long-term effects of omeprazole on gastric acid secretion were examined in 11 patients with Zollinger-Ellison syndrome. Basal gastric acid secretion was inhibited by 50% 3 h after a single 60-mg dose of omeprazole and 78% 4 h after administration of omeprazole. Patients were treated with a single daily dose of omeprazole, and the dose requirement was defined as the lowest dose of omeprazole that would reduce gastric acid secretion to less than 10 mEq/h during the last hour before the next dose. The mean daily dose requirement was 70 mg (range 20-160 mg). Ten of the 11 patients were given omeprazole once a day and 1 patient required omeprazole every 12 h. When omeprazole was discontinued after several months of therapy, mean basal gastric acid secretion was inhibited by greater than 50% 48 h after administration of omeprazole. Omeprazole continued to inhibit gastric acid secretion during 1-9 mo of therapy and patients remained free of toxicity or side effects related to omeprazole. Omeprazole is a highly effective inhibitor of gastric acid secretion in patients with Zollinger-Ellison syndrome. Because of its potency and long duration of action, omeprazole offers an advance in convenient medical therapy for Zollinger-Ellison syndrome compared with the histamine H2-receptor antagonists.

Adult↗
PubMed1985

Famotidine, a new, potent, long-acting histamine H2-receptor antagonist: comparison with cimetidine and ranitidine in the treatment of Zollinger-Ellison syndrome.

Famotidine, a new, potent, long-acting histamine H2-receptor antagonist was compared with cimetidine and ranitidine in 9 patients with Zollinger-Ellison syndrome. The mean minimum daily requirement of famotidine to control gastric acid hypersecretion was 0.24 g (range 0.08-0.48 g) compared with 2.1 g (range 0.6-3.6 g) for ranitidine and 7.8 g (range 1.2-13.2 g) for cimetidine. Equally potent doses of the three drugs had similar onsets of action, but the duration of action of famotidine was 30% longer than the duration of action of either ranitidine or cimetidine (p less than 0.05). Eight patients were treated for up to 9 mo (mean 6 mo) with good control of gastric acid hypersecretion and with no evidence of biochemical or hematologic toxicity. These studies demonstrate that famotidine is nine times more potent than ranitidine and 32 times more potent than cimetidine, has a longer duration of action than ranitidine or cimetidine, and is both safe and effective in the long-term therapy of Zollinger-Ellison syndrome.

Aged↗
PubMed1985

Bombesin-induced residual stimulation of amylase release from mouse pancreatic acini.

When dispersed acini from mouse pancreas are first incubated with bombesin, washed, and then reincubated with fresh incubation solution containing no bombesin, there is significant residual stimulation of amylase release. Induction of residual stimulation is relatively rapid in that significant stimulation occurs as early as after 15 s of first incubation with bombesin. Induction of residual stimulation of amylase release per se is temperature independent, but induction does occur more rapidly when acini are first incubated at 37 degrees C than when they are first incubated at 4 degrees C. Residual stimulation of amylase release persists for at least 75 min in acini that have been first incubated with bombesin at 37 degrees C. The maximal residual stimulation of amylase release obtained with pancreatic acini that have been first incubated with bombesin and then washed is 45% greater than the maximal stimulation obtained when bombesin is added directly to the incubation medium. In terms of their abilities to cause residual stimulation of amylase release, litorin and ranatensin are equal to bombesin in potency and efficacy. Gastrin-releasing peptide is approximately 70% as efficacious as bombesin in causing residual stimulation of amylase release.

Amylases↗
PubMed1985

Proglumide analogues: potent cholecystokinin receptor antagonists.

Proglumide [N-(benzoyl)-L-glutamic acid-1-di-n-propylamide] is a specific cholecystokinin receptor antagonist. In the present study we synthesized various analogues of proglumide and used pancreatic acini from guinea pig pancreas to examine the abilities of these analogues to function as cholecystokinin receptor antagonists. Each analogue inhibited cholecystokinin octapeptide-stimulated amylase secretion but did not stimulate amylase secretion when present alone. There was a close correlation between the ability of a particular analogue to inhibit the action of cholecystokinin on acinar cell function and its ability to inhibit binding of 125I-cholecystokinin. Structure-function studies demonstrated that neither the dipropylamide nor the benzoyl moieties are essential for inhibiting the action of cholecystokinin but that both groups are important in determining the inhibitory potency. Replacing the dipropylamide group with a hydroxyl group caused a 13-fold decrease in potency. Replacing the benzoyl moiety by an acetyl group caused a 30- to 40-fold decrease in inhibitory potency, whereas replacing the benzoyl moiety by a p-chlorophenoxyacetyl or phenoxyacetyl moiety caused a 75-fold increase in potency. Replacing both the dipropylamide moiety with a hydroxyl group and the benzoyl moiety with a phenoxyacetyl group resulted in a 5-fold decrease in inhibitory potency. Inhibition of cholecystokinin-stimulated amylase release by both the phenoxyacetyl and p-chlorophenoxyacetyl analogues was competitive in nature, fully reversible, and specific for those secretagogues that interact with the cholecystokinin receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

Amylases↗
PubMed1984

Comparison of the effectiveness of ranitidine and cimetidine in inhibiting acid secretion in patients with gastric hypersecretory states.

The H2-histamine receptor antagonists ranitidine and cimetidine were compared for their abilities to control gastric acid hypersecretion on a short- and long-term basis in 22 patients with gastric acid hypersecretory states. Nineteen patients had Zollinger-Ellison syndrome, one patient had systemic mastocytosis, and two patients had idiopathic hypersecretion. The rates of onset of the action of cimetidine and ranitidine were the same. The actions of both drugs were increased by anticholinergic agents, and there was a close correlation between the daily maintenance dose of each drug needed to control acid secretion. However, ranitidine was threefold more potent than cimetidine both in acute inhibition studies and in the median maintenance dose needed (1.2 g per day for ranitidine and 3.6 g per day for cimetidine). Sixty percent of the males developed breast changes or impotence while taking cimetidine and in all cases these changes disappeared when cimetidine was replaced by ranitidine. Treatment with high doses of cimetidine (one to 60 months; median, 11 months) or ranitidine (two to 31 months; median, 14 months) was not associated with hepatic or hematologic toxicity or alterations of serum gastrin concentrations, but ranitidine therapy was associated with a significantly lower serum creatinine level than seen with cimetidine therapy. The results show that both drugs can adequately inhibit acid secretion in patients with gastric hypersecretory states. Both are safe at high doses, but ranitidine is threefold more potent and does not cause the antiandrogen side effects frequently seen with high doses of cimetidine.

Adult↗
PubMed1984

Discovery of a cholecystokinin analogue with partial agonist activity.

In dispersed acini from guinea pig pancreas, cholecystokinin-(27-32)-amide [CCK-(27-32)-NH2] did not stimulate amylase secretion and inhibited the stimulation caused by CCK-(26-33). In dispersed acini from mouse or rat pancreas, CCK-(27-32)-NH2 stimulated amylase secretion. The stimulation of amylase secretion caused by a maximally effective concentration of CCK-(27-32)-NH2 was less than that caused by a maximally effective concentration of cholecystokinin-(26-33), and in contrast to the action of cholecystokinin-(26-33) supramaximal concentrations of CCK-(27-32)-NH2 did not cause submaximal stimulation of amylase secretion. Dibutyryl cGMP and proglumide each inhibited the stimulation of amylase secretion caused by CCK-(27-32)-NH2. CCK-(27-32)-NH2 inhibited binding of 125I-labeled CCK to mouse and rat pancreatic acini. These results indicate that, in mouse and rat pancreatic acini, CCK-(27-32)-NH2 is a partial agonist and that this partial agonist activity is produced by occupation of the CCK receptor by CCK-(27-32)-NH2.

Amylases↗
PubMed1984

Comparison of ranitidine and cimetidine in the treatment of gastric hypersecretion.

The H2-histamine receptor antagonists, cimetidine and ranitidine, were compared for their abilities to control acid secretion on a short- and long-term basis in 13 patients with gastric hypersecretory disorders. The rate of onset of action did not differ between the two drugs. The actions of both drugs were increased by an anticholinergic agent, and there was a close correlation between the daily maintenance dose of each drug needed to control acid secretion. However, ranitidine was threefold more potent than cimetidine and no male patient developed breast changes or impotence while taking ranitidine. Treatment with high doses of ranitidine for 6 to 25 months was not associated with hepatic or hematologic toxicity or alterations of serum gastrin levels, but was associated with a significantly lower serum creatinine level than that seen with cimetidine therapy. These studies show that ranitidine can adequately inhibit acid secretion in patients with gastric hypersecretory disorders, is safe at high doses, does not cause the antiandrogen side effects frequently seen with high doses of cimetidine, and is threefold more potent than cimetidine. Patients who are relatively resistant to cimetidine will have proportional resistance to ranitidine.

Adult↗