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Biomedical subjects

L F Williams

Publications and source records attributed to L F Williams.

At least 55 records · Page 3Linked to original sources
PubMed1983

Histamine receptors in primate gallbladder.

The effect of intravenous histamine on intragallbladder pressure (GBp) and subsequent modification of the histamine response by H1- and H2-antagonists was investigated in an awake baboon model. Responses to specific H1- and H2-agonists were also examined in order to further elucidate gallbladder histamine responses. Gallbladder volume (GBv) was arbitrarily set at 60-70% of observed resting GBv, and drugs were then infused intravenously with continuous monitoring of GBp. Histamine administration resulted in a logarithmic dose--response curve with a maximal increase in GBp equal to 31.7 mm Hg at a dose of 0.0625 mg of histamine. Infusion of the H1-antagonist diphenhydramine hydrochloride (Benadryl) resulted in a decreased GBp response to histamine when compared to preblocker response at all doses studied. On the other hand, histamine response following administration of the H2-antagonist metiamide was significantly greater than the preblocker histamine response. Infusion of the H1-agonist 2-pyridylethlamine resulted in a dose-dependent increase in GBp similar to the histamine curve, while infusion of the H2-agonist dimaprit resulted in consistent decreases in GBp. These results extend previous observations in subprimate preparations and demonstrate the presence of both stimulatory H1-receptors and inhibitory H2-receptors in an in situ primate model.

Animals↗
PubMed1982

Effects of pH on in vitro gallbladder responses to cholecystokinin octapeptide.

We investigated the effect of pH change on octapeptide cholecystokinin's ability to contract guinea pig gallbladder strips. In the absence of exogenous drugs, pH changes had no demonstrable effect on gallbladder tension. However, when gallbladder strips were contracted with CCK-OP at pH 7.3, increasing the pH in the muscle bath to 7.8 produced further increases in tension at each dose studied (P less than 0.025). Subsequently, decreasing the bath pH to 6.9 decreased the strip tension to less than that observed at pH 7.3 (P less than 0.025). Reversing the order in which these pH alterations were made produced similar results; a pH decrease from 7.3 to 6.9 decreased the response to CCK-OP at the two highest doses (P less than 0.025), while subsequent elevation of pH raised the tension to levels greater than those observed at pH 7.3 (P less than 0.01). Furthermore, contracting the strips at pH 8.0 and slowly decreasing pH at a rate of 0.1 pH units per minute consistently produced an acceleration of tension decay as pH fell. After contracting the strip at pH 6.7, slow increases in pH reversed the tension decay and enhanced the contractile response as pH was increased from 6.7 to 8.0. These results demonstrate that pH changes alter the gallbladder contractile response to cholecystokinin. Although this phenomenon has been reported for a number of other physiologic agents, we believe this is the first such demonstration for a peptide hormone.

Animals↗
PubMed1981

Lower gastrointestinal bleeding. Diagnostic approach and management conclusions.

The management of patients with lower gastrointestinal bleeding requires a systematic approach based on defined diagnostic and therapeutic methods. Although in 80 percent of patients bleeding will stop spontaneously, 25 percent will have rebleeding and 50 percent of those with rebleeding will bleed again. Angiography documents specific bleeding sites but raises questions related to the incidence, site and frequency of bleeding, as well as the necessity of demonstrating extravasation. We reviewed 49 arteriograms performed for lower gastrointestinal bleeding. We conclude from our findings that angiography identifies a presumptive cause of bleeding in 49 percent of patients; angiography identified the site of bleeding in 86 percent of the patients with active bleeding, thus allowing segmental colectomy. We believe that documentation of angiodysplasia in a patient with lower gastrointestinal bleeding is presumptive evidence for the site of bleeding. Angiography is useful and worthwhile in the work-up of patients with lower gastrointestinal bleeding in an attempt to plan localized, definitive resection, and this may lead to a lower mortality rate.

Angiography↗
PubMed1981

Retrocecal appendicitis.

The clinical presentation of 105 cases of retrocecal appendicitis was reviewed. Thirty-six percent of the patients had the classic appendicitis scenario of periumbilical pain localizing to the right lower quadrant, accompanied by anorexia, nausea and vomiting, and tenderness and guarding in the right lower quadrant. The remaining 64 percent had subtle variations of this presentation. Retrocecal appendicitis did not have a distinctive clinical pattern in our series. Twelve of the 105 retrocecal appendices were also retroperitoneal. The diagnosis was delayed in four patients and two had flank pain. Five of the twelve appendices were either gangrenous or perforated. Although the number of patients is small, we conclude that the traditional type of retrocecal appendicitis can occur in the retroperitoneal subgroup but that his anatomic variation is infrequent. The incidence in our series was 2.5 percent.

Adolescent↗
PubMed1981

Pathogenesis of cholesterol gallstones.

The factors leading to cholesterol cholelithiasis are probably multiple. Although the secretion of bile supersaturated with cholesterol seems to be a common feature among all patients who form cholesterol stones, a variety of pathophysiologic events can produce an increase in lithogenicity. Dietary factors, particularly in the grossly obese, lead to an absolute increase in secretion of cholesterol into bile. Occasionally, excessive loss of the bile salt pool, for example with regional ileitis, may decrease the ability of bile salts to solubilize cholesterol. In many other, subtle alterations in the enterohepatic circulation of bile salts may adversely affect solubility by both decreasing the secretion of bile salts and increasing the secretion of cholesterol. Regardless of its cause, supersaturation of bile with cholesterol appears to be a prerequisite for gallstone formation. However, additional factors within the gallbladder, such as increased secretion of glycoprotein, increased absorption of fluids, infection, and stasis, appear to contribute to the formation of macroscopic stones.

Animals↗
PubMed1981

Primary sclerosing cholangitis.

In spite of an improved understanding of the etiology of primary sclerosing cholangitis, which supports the use of immunosuppressive therapy with steroids and azathioprine, these pharmacologic manipulations have not altered the ultimate outcome of the disease. Drainage remains the most accepted mode of therapy when possible. Recent advances in diagnosis with ERCP and treatment with transhepatic biliary drainage may change the time-honored surgical approach to this disease as these techniques become more widely available. Until then, however, proper surgical management depends upon a high index of suspicion at the time of laparotomy so that irrevocable damage to the biliary tree will not be done prior to the establishment of the correct diagnosis. Simple drainage of the biliary tree will provide symptomatic relief in some patients; unfortunately, most patients will succumb to progressive biliary cirrhosis or sepsis in spite of all treatment.

Adult↗
PubMed1981

Postoperative fiberoptic choledochoscopy.

Twenty-eight patients underwent fiberoptic T-tube tract choledochoscopy for the diagnosis, management, and treatment of filling defects seen on postoperative T-tube cholangiograms. In 22 patients, 59 retained stones were treated by extraction. In six other patients with diagnostic problems arising from cholangiogram defects, the diagnosis was made by direct vision and biopsy specimen examination. There were multiple papillary adenocarcinomas in one patient, and normal mucosal folds in two patients. The procedure was accompanied by a low complication rate, with two patients developing pancreatitis and five patients developing transient fever. The advantages of the procedure are a direct examination of the biliary tree with the facility to remove stones and biopsy lesions under direct vision.

Adult↗
PubMed1981

Mechanical properties of primate gallbladder: description by a dynamic method.

Biomechanical theory was applied to devise a dynamic method for describing gallbladder tone in an in situ baboon model. Under pentobarbital sodium (Nembutal) anesthesia, cyclical infusion of bile into and withdrawal of bile from the gallbladder with continuous pressure monitoring allow instantaneous measurement of the pressure-volume ratio and thus of mean gallbladder compliance. This paper describes the method and details the manner of data analysis. Pharmacologic and hormonal agents with known gallbladder effects are used in order to demonstrate the sensitivity of the method. Pilocarpine, histamine, and cholecystokinin cause contraction of the primate gallbladder smooth muscle; this contraction is reflected in decreased compliance by continuous monitoring. Atropine administration results in increased ability to accommodate volume infusions; this effect has not been demonstrated by static monitoring in previous experiments. This new method allows continuous monitoring of compliance and offers both simplicity and sensitivity when compared with previous methods.

Animals↗
PubMed1980

Choledochoscopic removal of retained stones via a T-tube tract.

Common duct stones retained after choledocholithotomy were removed in 11 patients under intravenous sedation using the Olympus fiberoptic choledochoscope passed through a T-tube tract. A total of 39 stones were removed during 12 procedures, with one patient requiring 2 procedures for complete stone removal. All common duct stones were removed, with no patient requiring further operation or procedures for stone removal. The complication rate was low; one patient had pancreatitis and four patients had a transient fever 8 to 12 hours after the procedure. Direct visualization proved an advantage in stone removal, and the patients were not exposed to the radiation required by the fluoroscopic method of stone extraction.

Adult↗
PubMed1980

Depression of B-lymphocyte levels in the peripheral blood of cows with mastitis.

The levels of B-lymphocytes in the peripheral blood of normal and mastitic cows were evaluated by fluorescent-antibody and erythrocyte-antibody-complement-rosetting techniques. Normal cows (N = 8) had 26.9 +/- 4.4% surface membrane immunoglobulin-positive lymphocytes, whereas mastitic cows (N = 6) had only 16.3 +/- 3.6% similar cells among lymphocyte preparations purified by the Ficoll-Paque density gradient separation and carbonyl iron phagocytosis methods. Studies on smiliar lymphocyte preparations by erythrocyte-antibody-complement-rosetting techniques showed that normal cows (N = 12) had 33.5 +/- 7.1% erythrocyte-antibody-complement-rosetting lymphocytes, whereas mastitic cows (N = 6) had 20.5 +/- 6.0% similar cells.

Animals↗
PubMed1979

Is pulmonary angiography essential for the diagnosis of acute pulmonary embolism?

The records of 158 patients who underwent pulmonary angiography for the presumed diagnosis of acute pulmonary embolism were retrospectively reviewed. Of the 111 patients in the category of high probability for pulmonary embolism based on clinical impression, 60 patients (54 per cent) had a positive pulmonary angiogram. Of the forty-seven patients in the low probability group, ten (21 per cent) had a positive angiogram. Forty-eight of the seventy-three patients (66 per cent) with a high probability lung scan had a positive pulmonary angiogram. Eleven of twelve patients (92 per cent) with a high probability ventilation-perfusion scan had a positive pulmonary angiogram, and two of eight patients (25 per cent) with a low probability ventilation-perfusion scan had a positive pulmonary angiogram. The mean PO2 of patients with a positive pulmonary angiogram was 64 mm Hg, and the mean PCO2 30 mm Hg. The mean PO2 of patients with a negative pulmonary angiogram was 63 mm Hg and the mean PCO2 34 mm Hg. Based on these data, we believe that the accuracy of pulmonary angiography in diagnosing acute pulmonary embolism is much higher than that of the clinical impression, arterial blood gas determinations, and lung scanning technics.

Acute Disease↗
PubMed1979

Gunshot wounds of the left upper abdominal quadrant associated with multiple intraabdominal injuries.

This study reviews low velocity gunshot wounds of the left upper quadrant of the abdomen and presents four cases recently treated at Boston City Hospital. All patients sustained multiple intraabdominal organ injuries and underwent prompt exploration. Hypotension on admission seemed to be the most reliable sign for a prolonged and complicated hospital course. The essential preoperative studies in stable patients should include a chest x-ray and intravenous pyelogram. Intraoperatively, injury to the body or tail or the pancreas is best managed by distal pancreatectomy and sump drainage. Exploration of the retroperitoneum is warranted for bleeding from the kidney. Initial maneuvers should be designed to control hemorrhage from the renal pedicle. If this is unsuccessful or the renal parenchyma is badly fragmented, nephrectomy should be performed. The complications noted in our patients, infection (pneumonia and left subphrenic abscess) and hemorrhage, are comparable to those reported in most large series. Pancreatic complications (fistulas, pseudocysts, and pancreatitis) were not noted.

Abdominal Injuries↗
PubMed1979

Acid alpha-naphthyl acetate esterase: presence of activity in bovine and human T and B lymphocytes.

Non-specific acid alpha-naphthyl acetate esterase (ANAE) activity was demonstrated in a majority of bovine peripheral blood lymphocytes, confirming and extending the observations on murine and human lymphocytes made by previous workers. Simultaneous study of both ANAE activity and spontaneous erythrocyte (E) or erythrocyte-antibody-complement (EAC) rosetting capability of the same bovine lymphocytes showed directly that, while 64.2 +/- 4.6 (SEM) % of bovine lymphocytes capable of forming E rosettes were ANAE positive, 38.3 +/- 0.8% of those forming EAC rosettes were also ANAE positive. Similar studies of human peripheral blood lymphocytes showed also that, while 80.6 +/- 2.2% of the lymphocytes capable of forming E rosettes were ANAE positive, 44.1 +/- 2.6% of EAC forming lymphocytes were ANAE positive. Thus the presence of ANAE activity in a majority of T lymphocytes and a significant proportion of B lymphocytes of both human and bovine peripheral blood is indicated. Human and bovine lymphocytes from phytohaemagglutinin (PHA)-stimulated cultures demonstrated greatly enhanced intensity of ANAE activity.

Animals↗