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Biomedical subjects

W F Bennett

Publications and source records attributed to W F Bennett.

At least 109 records · Page 6Linked to original sources
PubMed1979

A study of protein phosphorylation in shape change and Ca++-dependent serotonin release by blood platelets.

Upon treatment with agents such as thrombin, collagen or concanavalin A, blood platelets change shape, secrete serotonin and phosphorylate two proteins having molecular weights of approximately 20,000 and 40,000. We have analyzed the relationship of this protein phosphorylation to shape change and release aided by the fact that while shape change occurs independently of extracellular calcium, release of serotonin displays a rather strict calcium requirement. Under limited calcium conditions, where virtually no serotonin release occurs, (Con A)-stimulated phosphorylation is uninhibited. Divalent cations (Mg++, Co++ and Zn++) also inhibit release but not phosphorylation. The microtubule effectors colchicine and D2O show concomitant effects on release and phosphorylation, indicating a microtubule involvement prior to phosphorylation. Papaverine inhibits release and phosphorylation while not strongly influencing shape change, suggesting that shape change does not require phosphorylation. We therefore conclude that phosphorylation of these proteins takes place after shape change but prior to release, and although it may be required for secretion to occur, the two processes are easily separated. Thus phosphorylation of these proteins is not likely to be an integral component of the release mechanism.

Animals↗
PubMed1979

Segmental resection for bronchogenic carcinoma: a surgical alternative for the compromised patient.

Over a twenty-year period, 44 patients with peripheral bronchogenic carcinoma who were unable to tolerate major pulmonary resection underwent segmentectomy as an alternative to nonoperative management. There were 2 immediate postoperative deaths. Of 31 patients eligible, 36% survived five years, and the mean survival time approached four years. Excluding those patients with undifferentiated small cell carcinoma, segmental resection in this compromised group offered a good chance for cure while providing reasonable palliation, and this procedure should be considered as a surgical option to other modalities of treatment commonly offered to these individuals.

Adult↗
PubMed1979

A method for investigating the role of calcium in the shape change, aggregation and serotonin release of rat platelets.

1. Effects of the platelet secretagogues thrombin and Concanavalin A (Con A) on shape change and release have been studied under conditions where external Ca2+ and ADP have been controlled. 2. In the absence of detectable aggregation both Con A- and thrombin-induced release of serotonin are markedly dependent upon extracellular calcium. 3. Con A, unlike thrombin, does not produce aggregation in calcium-supplemented medium. 4. The above property of Con A suggests that, in combination with added creatine phosphate and creatine phosphokinase, this ligand will be of value in the analysis of calcium-dependent release in platelets.

Animals↗
PubMed1979

Biochemical and physiological studies of long-term synaptic plasticity.

High frequency stimulation of fiber systems in the mammalian hippocampus produces a semipermanent increase in synaptic efficacy. This effect, long-term potentiation (LTP), has been of considerable interest as a potential substrate of memory due to its rapid onset and extreme persistence. Experiments are described that indicate that the locus of LTP is confined to the synaptic complex of the fibers stimulated; further, Ca2+ is shown to be essential for the initiation of LTP and may play a role in triggering this increase in synaptic efficiency. Data from biochemical analyses of LTP indicate that a 40,000 dalton synaptic membrane protein shows a highly reliable change in its endogenous phosphorylation following high frequency hippocampal stimulation. Phosphorylase kinase, a Ca2+ sensitive enzyme, is shown to specifically catalyse the phosphorylation of this 40,000 dalton protein. The data are discussed in terms of a working model in which the Ca2+ dependent phosphorylation of the 40,000 dalton protein produced by high frequency stimulation is a biochemical intermediate in the production of LTP.

Animals↗
PubMed1978

A twenty-year analysis of the results of sleeve resection for primary bronchogenic carcinoma.

Ninety-six patients with primary bronchogenic carcinoma were treated by lobectomy with sleeve resection of the bronchus, over a 20 year period (1958 through 1977). In 80 resections undertaken prior to 1973, a 5 year survival rate of 34 percent was realized, with an operative mortality rate of 7.5 percent. Survival at 10 and 15 years has been assessed. A review of factors influencing survival has been undertaken and the biologic behavior of these pulmonary neoplasms, modified by sleeve resection, has been outlined. Of interest is the high rate of local recurrence accounting for death within 5 years postoperatively and the late incidence in the survivors of second malignancies and other diseases of surgical interest. Sleeve resection represents a surgical alternative in selected cases of bronchogenic carcinoma in which wider resection may be hazardous, and the indications should be extended to include some lesions commonly managed by pneumonectomy.

Adult↗
PubMedDate not supplied

Imaging prior to second-look surgery for carcinoma.

Technical advances in imaging are barely keeping pace with the need for detailed pre-operative imaging in second-look surgery. Although the majority of intra-abdominal recurrence can be detected at surgery, pre-operative knowledge of possible sites of involvement will provide more efficient use of operative time. Dynamic incremental bolus CT is the modality of choice when evaluating these patients, even though magnetic resonance imaging is approaching, and may exceed, computed tomography in utility in the abdomen. Monoclonal antibody radioimmunoscintigraphy is useful for extra-abdominal sites of recurrence. Further technical advancement is needed to make it useful in the abdomen.

Abdominal Neoplasms↗
PubMedDate not supplied

Radiographic manifestations of eosinophilic gastroenteritis.

Eosinophilic gastroenteritis (EG) is a rare inflammatory disease of unknown etiology, characterized by focal or diffuse eosinophilic infiltration of the gastrointestinal tract. Although little over 250 cases of EG have been reported in the literature, EG is probably more common than reports in the literature would indicate. A retrospective review of 25 patients with EG along with a review of the literature was done to identify clinical, laboratory, radiographic, and therapeutic features. An allergic disorder was present in 14 (56%) and a peripheral eosinophilia was present in 24 (96%) of our patients. The most common radiographic manifestations of the stomach and small bowel included stenosis and fold thickening, respectively. Thirteen patients had esophageal involvement, with the esophageal stricture being the most common abnormality found in these patients. Steroids produced a good therapeutic result in most patients; the remaining patients responded to cromolyn and/or surgery.

Adult↗
PubMedDate not supplied

Cirrhosis: spectrum of findings on unenhanced and dynamic gadolinium-enhanced MR imaging.

The appearance of the cirrhotic liver on computed tomography can be difficult to evaluate and can frustrate the radiologist distinguishing benign from malignant lesions. Hepatic edema, fibrosis, atrophy, and vascular abnormalities are common in the cirrhotic liver and produce derangements in morphology, attenuation, and perfusion, limiting the accurate characterization of hepatic masses. With the development of fast magnetic resonance (MR) sequences and dynamic postgadolinium-enhanced imaging, most hepatic lesions with uncertain etiology on computed tomography can be accurately characterized on MR imaging. We describe MR imaging techniques useful for imaging cirrhosis and its complications. We also illustrate the spectrum of findings in the cirrhotic liver on dynamic gadolinium-enhanced MR imaging, including reticular and confluent fibrosis, fatty infiltration, hemochromatosis, regenerating nodules, dysplastic nodules, hepatocellular carcinoma, and sequela of portal hypertension.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Primary angiosarcoma of the spleen--CT, MR, and sonographic characteristics: report of two cases.

Primary angiosarcoma of the spleen is a rare entity, but it is the most common primary splenic malignancy. These tumors demonstrate an aggressive growth pattern and can be single or multiple. The diagnosis should be suspected in a patient who presents with splenomegaly but without evidence of lymphoma, malaria, leukemia, or portal hypertension. The tumor may also present with acute abdominal symptoms secondary to spontaneous splenic rupture. We describe two cases of primary angiosarcoma of the spleen with computed tomographic, magnetic resonance, and sonographic features.

Adult↗
PubMedDate not supplied

CT evidence of calcification within a small cell carcinoma of the lung.

Calcification in bronchogenic carcinoma is rare. When found it is usually focal in nature and felt by many to be coincidental granulomatous disease. To our knowledge this case report is the first computerized tomography (CT) description of diffuse, amorphous calcification in bronchogenic carcinoma, specifically, small cell.

Biopsy↗
PubMedDate not supplied

Specificity of the Speed's test: arthroscopic technique for evaluating the biceps tendon at the level of the bicipital groove.

A positive Speed's test result is usually thought to suggest inflammation or lesions related to the biceps/labral complex. The specificity, sensitivity, and positive and negative predictive values are determined for the Speed's test. A prospective study design was developed for all patients with shoulder pain who presented between October 1, 1994 and February 28, 1995. The clinical results of the Speed's test were correlated with biceps/labral pathology by direct arthroscopic visualization. A neuroprobe is used to pull the biceps tendon into the articular portion of the glenohumeral joint so as to visualize the biceps tendon at the level of the bicipital groove. Forty-six shoulders in 45 patients, 31 men (average age, 53 years; range, 16 to 76 years) and 14 women (average age, 64 years; range, 30 to 80 years) with 26 dominant and 20 nondominant extremities were operated on during this time interval. The clinical evaluation showed that the speed's test was positive in 40 shoulders. Biceps/labral complex pathology was present in 10 of these patients. A specificity of 13.8%, a sensitivity of 90%, a positive predictive value of 23%, and a negative predictive value of 83% were calculated. Thus, it is concluded that the Speed's test is a nonspecific but sensitive test for macroscopic biceps/labral pathology. This clinical examination is positive with a various number of other pathological shoulder problems.

Adolescent↗