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Biomedical subjects

H H Lawson

Publications and source records attributed to H H Lawson.

At least 19 recordsLinked to original sources
PubMed1997

Comparison of the effects of the interposition of 'narrow' cycloperistaltic v. antiperistaltic segments on fluid perfusion through isolated loops of jejunum.

Experimental studies in dogs showed a delaying action of the cycloperistaltic (C-P) segment when interposed in isolated loops of jejunum ('narrow' C-P segments) and between stomach and duodenum after Billroth I gastrectomies ('wide' C-P segments). This study was designed to establish whether there were any differences in the delaying action on the passage of perfused fluids between isolated loops of jejunum with C-P and antiperistaltic (A-P) segments interposed. The latter is the surgical technique that is currently considered the gold standard for such actions. Two isolated segments of jejunum with the ends exteriorised as jejunostomies (Thiry-Vella (T-V) loops) were created in each of 4 dogs. Towards the end of one, a C-P segment with a diameter 70% that of the jejunum ('narrow' C-P segment) was interposed. Towards the end of the other, a reversed A-P segment was interposed. Fluid containing 14C-labelled polyethylene glycol was infused at a rate of 4 ml/min through all the 8 loops (4 dogs) for 1 hour (6 experiments per dog). Descriptive statistics (means and standard errors) show that no obvious differences in volume of output, absorption and pooling existed between T-V loops with 'narrow' C-P and A-P segments. The delaying effect in the passage of fluids of the C-P segment, shown in previous experiments, does not appear to be superior to that of the A-P segment. This statement is made with some reservation as the number of animals involved was relatively small and analytical statistics could not be used.

Animals↗
PubMed1995

Interposition of 'wide' cycloperistaltic segments into isolated segments of jejunum--influence on fluid perfusion.

Two isolated jejunal segments (Thiry-Vella (T-V) loops) were created in 7 dogs. One contained a 'wide' cycloperistaltic (C-P) segment while the other, acting as a control, did not. The C-P segment had the same diameter as the jejunum. Fluid perfusion experiments showed that there were no changes in the volume of output, absorption and pooling of the fluid in the T-V loops containing the 'wide' C-P segment. This was in contrast with significant changes shown in earlier experiments using 'narrow' C-P segments.

Animals↗
PubMed1994

Interposition of 'narrow' cycloperistaltic segments into isolated segments of jejunum--influence on fluid perfusion.

Two isolated segments of jejunum with the ends exteriorised as jejunostomies were created in each of 8 dogs. Towards the end of one of the two, a cycloperistaltic (C-P) segment, with a diameter 70% of that of the jejunum, was interposed. Fluid containing C-labelled polyethylene glycole [corrected] was infused at 4 ml/min through each of the 16 preparations and the results were compared. The presence of a C-P segment significantly reduced the volume of output (with C-P segment--mean (+/- standard deviation) 155.27 +/- 14.81 ml/h v. without C-P segment--210.09 +/- 19.41 ml/h) (P < 0.001) and increased absorption (with C-P--45.44 +/- 20.86 ml/h v. without C-P--20.48 +/- 8.42 ml/h) (P < 0.001) and pooling (with C-P--39.29 +/- 16.99 ml/h v. without C-P--9.42 +/- 17.16 ml/h) (P < 0.001). The C-P segment therefore delayed the passage of the perfused fluid.

Anastomosis, Surgical↗
PubMed1993

The role of total enteral nutrition in pancreatic disease.

Conflicting data have been reported on the use of total enteral nutrition (TEN) in pancreatic disease. TEN was used in 17 patients who were candidates for nutritional support with total parenteral nutrition (TPN). There were 7 patients with internal pancreatic fistulas, 2 with protracted traumatic pancreatitis, 7 with severe alcoholic pancreatitis and 1 with a traumatic pancreatic pseudocyst. The mean inhospital stay was 30 days. Precision LR was administered orally or nasally for a mean of 16 days. Five patients with internal pancreatic fistulas were healed during the initial admission on TEN, 1 required surgery and 1 defaulted from hospital treatment. Nine patients with pancreatitis improved on TEN with resolution of pseudocysts or phlegmons (8 patients); 1 patient required a cystojejunostomy. Three patients who defaulted on TEN and consumed a ward diet had relapse of the pancreatitis, which responded rapidly to re-institution of hyperalimentation. There was no mortality in this group of patients. This preliminary report suggests that TEN may be considered as an alternative to TPN for nutritional support in pancreatic disease.

Adult↗
PubMed1992

Gastric acid secretion and gastrin release in the baboon.

Significant species differences have been demonstrated in gastric physiology, a factor that limits extrapolation of animal data to man. Primate physiology is thought to be similar to that of man; however, gastric function has not been adequately documented in the primate. In the present study six baboons (body weight 25.5 +/- 1.8 kg) were trained to sit in a chair and gastric acid secretion and gastrin release was studied in conscious animals. Mean basal acid secretion was 1.3 +/- 0.1 mmol (H+)/hr. Maximum output after pentagastrin (12 micrograms/kg/hr) was 9.5 +/- 0.9 mmol (H+)/hr and 11.0 +/- 0.4 mmol (H+)/hr after histamine (40 micrograms/kg/hr). A statistically significant (by cosinor analysis) circadian rhythm was demonstrated for intragastric pH over 24 hr in fasted baboons (P less than 0.001). Mean basal serum gastrin level was 37.7 +/- 8.3 pg/ml. The integrated gastrin response after administration of a protein rich meal was 2.52 +/- 0.07 ng x min/ml and this increased to 5.17 +/- 0.18 ng x min/ml (P less than 0.05) following simultaneous administration of a meal with atropine (0.2 mg/kg) (P less than 0.05). Our results suggest that there is significant basal and stimulated acid secretion in the baboon; the amount of acid secreted is similar to that reported in man. Gastric pH demonstrated a circadian rhythm. Postprandial gastrin release was significantly enhanced by cotreatment with atropine. As the present findings are similar to those previously reported in man, the baboon may be a useful model for further studies in gastric physiology and experimental peptic ulceration.

Animals↗
PubMed1991

Significance of gastric surface epithelial metaplasia in the duodenum.

An experimental study was undertaken to establish whether normally occurring gastric surface epithelial metaplasia was increased in chronic duodenitis caused by explanting duodenal mucosa in dogs. All the histological changes of chronic duodenitis were observed in the explants. However, as established by morphometry, the distribution and the amount of gastric surface epithelial metaplasia remained unchanged in 9 dogs following periods of explantation from 3 months to 1 year. It was concluded that under these experimental conditions, gastric surface epithelial metaplasia was not a manifestation of chronic duodenitis.

Animals↗
PubMed1989

Capsular penetration and perforation in pleomorphic adenoma of the parotid salivary gland.

Both penetration and perforation of the capsule were seen on the superficial aspect of pleomorphic adenomas. Only penetration was noted on the deep aspect, where the tumour was adjacent to the facial nerve. In terms of local recurrence this may explain why it appears to be safe to separate the deep aspect of the tumour from the facial nerve without a wide margin of normal parotid tissue.

Adenoma, Pleomorphic↗
PubMed1989

Post-traumatic parotid fistulae and sialoceles. A prospective study of conservative management in 51 cases.

The management of parotid sialoceles and fistulae have been unsatisfactory in the past, and numerous methods of treatment with varying success and morbidity have been described. The present prospective study reports results of conservative therapy in 51 patients over a 3-year period. In 50 patients, the injury healed upon conservative management. During the early phase of the study, a limited conservative regimen through which the patients received nothing orally for 5 days only was used. During the latter part of the study, patients were administered nothing orally until complete healing of the injury. In terms of the time it took for healing of the injury, the differences of the two regimens (24 +/- 4 vs. 9.4 +/- 0.9 days) was highly significant (p less than 0.001). The response to conservative management depended on the severity of injury as demonstrated by sialography. Injury to minor intraparotid ducts (G1) healed in significantly less time compared with that to a major intraparotid duct (G2) or ductal injuries (p less than 0.001). There was no difference between the healing of G2 injury (10.3 +/- 1.8 days) and partial ductal transections (10.5 +/- 2.2 days) (p greater than 0.05). There was a significantly greater delay in healing with complete duct transections (21.5 +/- 3.7 days) compared with partial duct transections and G2 injuries (10.2 +/- 2.1 days) (p less than 0.01). There was no difference in the mean period for healing between salivary fistulae and sialoceles (p greater than 0.05). It is concluded that a new classification of parotid fistulae based on sialographic findings has prognostic and therapeutic value. Furthermore, the excellent results achieved with conservative therapy in this study suggest that it may be the initial treatment of choice for parotid fistulae.

Acute Disease↗
PubMed1989

Technetium-pertechnetate uptake by ectopic antral mucosa. An experimental study.

The ability of ectopically placed fundic mucosa and retained antral mucosa to concentrate technetium has previously been demonstrated. The ability of ectopically placed antral mucosa to concentrate technetium was investigated. The denervated antrum implanted into the colon concentrated technetium in 5 dogs. However, this response was significantly less than that of parietal cell-containing mucosa (P less than 0.005) of the stomach. Technetium scanning may be useful in detecting ectopic and retained antral mucosa.

Animals↗
PubMed1989

The duodenal mucosa in health and disease. A clinical and experimental study.

Normal Human Duodenal Mucosa. There are three clearly identifiable different histologic types of normal human duodenal mucosa. These have been termed antral type-duodenal mucosa, transitional-type duodenal mucosa, and jejunal-type duodenal mucosa. The mucosa has a characteristic fingerlike distribution at the gastroduodenal junction. Transitional-type duodenal mucosa, one of the three types of normal mucosa, is also referred to as gastric epithelium or gastric surface epithelial metaplasia. Evidence is presented to support the view that this is a normal finding and is not an indication of duodenitis. Normal variations of villi are described, which again cannot be regarded as indicators of duodenitis. The normal shape and mucosal lining of the pyloric sphincter are described. Abnormal Duodenal Mucosa. Acute and chronic duodenal ulcers occur in jejunal type duodenal mucosa. It is suggested that the three different types of mucosa vary in their degree of susceptibility to the effect of acid hypersecretion. Aspects of the diagnosis of duodenitis are reviewed. Duodenitis and gastritis both are patchy conditions, which may persist or become worse in spite of ulcer healing. Without the availability of accurate morphometric methods and quantitative immunocytochemistry, the classification suggested by Jenkins et al has much to recommend it. When the Jenkins classification was used in giant duodenal ulceration, there was widespread duodenitis, which was not seen in conventional duodenal ulceration. Chronic duodenitis does not appear to be related to chronic duodenal ulceration as chronic gastritis is related to chronic gastric ulceration. Regeneration of Duodenal Mucosa. The Brunner glands as well as the crypts of Lieberkühn appear to regenerate from cells in the base of these crypts, where there is a marked increase in mitotic activity. It is rare to see mitotic activity in normal or regenerating Brunner glands. Surface epithelium regenerates from adjacent normal villi, not from the Brunner glands.

Duodenal Ulcer↗
PubMed1989

Canine duodenal mucosal protection.

In an experimental study on dogs the absence of bile or both bile and pancreatic juice from the duodenum did not result in ulceration. It is suggested that the inhibitory control of the duodenum on acid secretion is the explanation for this observation.

Animals↗
PubMed1988

Healing of the right and left colon. An experimental study.

An experimental study investigated the relative healing properties of the unprepared right and left colon of the baboon. Colonic healing was assessed in three ways: anastomostic leakage, hydroxyproline concentration and breaking strength. The results suggest that healing on the two sides of the colon is similar.

Animals↗
PubMed1988

Definition of gastroduodenal junction in healthy subjects.

To study the appearance and distribution of the normal mucosa at the gastroduodenal junction in man, 14 specimens of normal mucosa, eight obtained during pylorplasty, and "relatively" normal specimens from the distal stomach and whole duodenum were examined microscopically. Three histologically distinct types of normal duodenal mucosa were found at this junction. These were termed antral type duodenal mucosa, transitional type duodenal mucosa (which is also referred to as gastric surface epithelial metaplasia), and jejunal type duodenal mucosa. Antral type duodenal mucosa appeared as a series of finger-like processes 1-3 mm long, circumferentially located around the junction of the antrum and duodenum; transitional type duodenal mucosa extended 2-3 mm beyond this; and the rest of the mucosa was jejunal type duodenal mucosa. The mucosa of the pyloric antrum can therefore lie adjacent to antral type duodenal mucosa, or adjacent to either of the components of transitional type duodenal mucosa.

Duodenum↗
PubMed1988

The effect of chronic acidification of the canine duodenum on gastrin release from the antrum transplanted into the colon.

Exogenous infusion of acid into the canine duodenum inhibits acid secretion stimulated by endogenously released and exogenously administered gastrin. The importance of this mechanism in normal acid homeostasis and in the inhibition of chronic endogenous acid hypersecretion is not established. In this study the classic Dragstedt model antral colonic transplant (ACT) was used to produce endogenous hypergastrinemia and acid hypersecretion. The effects of the ACT when the duodenum was retained in continuity with the stomach (gastroduodenostomy) were compared with those obtained when the duodenum was no longer in continuity with the stomach (gastrojejunostomy). The duodenum markedly suppressed gastrin release (p = 0.003) and gastric acid secretion (p = 0.005) in each of the four dogs. The dogs remained free of ulcers for 8 months after gastroduodenostomy and ACT. However, after conversion to gastrojejunostomy, large, chronic peptic ulcers developed after a mean of 3.5 months. The inhibitory effect of the duodenum on gastric release and gastric acid secretion protected the dog against ulceration for an extended period. The duodenum may be the major site of inhibitory control of acid secretion and endogenous gastrin release in dogs.

Anastomosis, Surgical↗