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Biomedical subjects

C D Johnson

Publications and source records attributed to C D Johnson.

At least 271 records · Page 15Linked to original sources
PubMed1988

Percutaneous placement of the Greenfield vena caval filter.

During the period from August 1986 to August 1987, 50 patients underwent percutaneous placement of a Greenfield vena caval filter from the right femoral vein, left femoral vein, or right internal jugular vein at our institution. All 50 patients had a contraindication to anticoagulation therapy or had complications of anticoagulation for deep venous thrombosis or pulmonary emboli. The percutaneous placement was accomplished in the angiographic suite with use of local anesthesia and was well tolerated by all patients. Only three complications related to the percutaneous approach occurred during the short-term follow-up (3 months to 1 year). These complications were deep venous thrombosis of the leg in two patients and misplacement of the filter in one patient. The three patients tolerated these complications well. We conclude that placement of Greenfield vena caval filters can be readily accomplished by means of percutaneous entry. Our experience demonstrated minimal associated morbidity and no mortality.

Aged↗
PubMed1988

Acquired hernias of the diaphragm.

We present our experience over five and a half years of acquired hernias of the diaphragm. Each case represents a different presentation of this condition, which may follow blunt or penetrating trauma or iatrogenic injury. Diaphragmatic hernia may present in the acute phase after injury but late presentation may occur after many years, with chronic abdominal or respiratory symptoms, or with acute intestinal obstruction. The problems in diagnosis and management are discussed.

Adult↗
PubMed1988

Imaging of fibrolamellar hepatocellular carcinoma.

The imaging studies of 12 patients with fibrolamellar hepatocellular carcinoma were reviewed in an attempt to characterize the appearance of the tumors and to stage them. The imaging studies showed that 10 (83%) of 12 tumors were solitary, one was multilobulated with several satellite nodules, and one was bilobed. Surface lobulations were present in nine (82%) of 11 tumors on CT, five of five on sonography, and seven (88%) of eight on angiography. A central scar was identified in five (45%) of 11 tumors on CT, three (60%) of five on sonography, and two (25%) of eight on angiography. Calcification was seen in six (55%) of 11 tumors on CT, four (80%) of five on sonography, and one (13%) of eight on plain films. The tumors were correctly staged as resectable or nonresectable by CT in eight (73%) of 11 patients, by sonography in four (80%) of five, and by angiography in five (63%) of eight. Understaging was responsible for all but one of the staging errors. Distinguishing fibrolamellar hepatocellular carcinoma from more common hepatocellular carcinoma can affect surgical planning and survival.

Adolescent↗
PubMed1988

Cholangiocarcinoma: diagnosis and evaluation of resectability by CT and sonography as procedures complementary to cholangiography.

The purpose of this study was to evaluate the usefulness of CT and sonography as procedures complementary to cholangiography in the detection and staging of cholangiocarcinoma. The studies of 42 patients with pathologically proved cholangiocarcinoma and preoperative CT (26 patients), sonography (30 patients), and cholangiography (31 patients) were reviewed blindly and retrospectively. The tumor was shown by CT in 69%, by sonography in 47%, and by cholangiography in 97% of patients. Three radiographic types of cholangiocarcinoma were identified: infiltrating stenotic (69%), bulky exophytic (19%), and polypoid intraluminal (12%). CT correctly staged 54%, sonography 50%, and cholangiography 58% of tumors as resectable (40%) or unresectable (60%). The sensitivities in detecting unresectability with CT, sonography, and cholangiography were 44%, 19%, and 43%, respectively; specificities were 78%, 100%, and 100%, respectively. CT and sonography combined with cholangiography increased the sensitivities to 64% and 50%, respectively. CT and sonography were complementary to cholangiography because they helped determine the extrabiliary extent of these tumors and therefore provided information on resectability.

Adenoma, Bile Duct↗
PubMed1988

Cystic pancreatic tumors: CT and sonographic assessment.

Thirty-five CT scans and 23 sonograms of 45 pathologically proved pancreatic cystic neoplasms (16 microcystic adenomas, 17 mucinous [macrocystic] cystadenomas, and 12 mucinous [macrocystic] cystadenocarcinomas) in 43 patients were retrospectively and blindly reviewed. Radiologic findings and their usefulness in differentiating microcystic from mucinous subtypes were assessed. The number of cysts within the tumors (more than six in microcystic adenomas and six or fewer in mucinous cystadenomas and cystadenocarcinomas) and the diameter of the majority of cysts within the tumor (less than or equal to 2 cm in microcystic adenomas and greater than 2 cm in mucinous tumors) were the most helpful radiologic findings in differentiating tumor types. Calcification was present in 38% of microcystic adenomas, 18% of mucinous cystadenomas, and 8% of mucinous cystadenocarcinomas by CT. Calcification was not definitely identified on any of the sonograms. A central scar was identified in only two (13%) of 16 microcystic adenomas. Blind retrospective review was often able to correctly classify tumors as either microcystic (CT, 93%; sonography, 78%) or mucinous (CT, 95%; sonography, 93%). All tumors with a typical appearance on either CT or sonography were categorized correctly. Cystic pancreatic tumors may be difficult to prospectively separate from other types of pancreatic cysts. Assuming a cystic neoplasm is present, it often can be classified correctly as microcystic or mucinous (macrocystic) by using the above criteria.

Adenoma↗
PubMed1988

Intra-operative air testing: an audit on rectal anastomosis.

Thirty three patients having an anastomosis to the rectum were studied prospectively to determine the usefulness of intra-operative air testing. The pelvis was filled with saline and the anastomosis was distended with air. Any leaks demonstrated were oversewn. A Gastrografin enema was performed on all the patients on the eighth postoperative day. Overall, there were 4 (12%) clinical leaks and 10 (30%) radiological leaks. In six patients with air leaks demonstrated at operation, two had a radiological leak, one of which presented clinically as well. We believe that in the other four patients a potential leak was probably avoided as a result of intra-operative air testing. This technique is simple, safe and effective and probably helps reduce leakage after colorectal anastomosis.

Aged↗
PubMed1988

The twist drain.

Explore the source record for details and available documents.

Connective Tissue↗
PubMed1987

Localization of choline acetyltransferase-like immunoreactivity in the embryonic chick retina.

Putative sites of acetylcholine synthesis in the retina of the embryonic and posthatched chick were localized immunohistochemically with antisera to choline acetyltransferase; the resultant choline acetyltransferase-like immunoreactivity (ChAT-IR) was compared to demonstrated sites of acetyltransferase (AChE) activity, and changes were followed in localization during development. The results confirmed the early and rapid course of development of the chick's retinal cholinergic system described in previous biochemical and morphological studies. Immunoreactivity was first detected at embryonic day 6.5 in cells close to the retina's vitreal surface. By 8 days it was present in cells in two juxtaposed rows; by the ninth day the two rows were separated and immunoreactivity was evident in two subliminae of the inner plexiform layer. On the tenth day distribution was like that in the posthatched chicken, in type I cholinergic cells in the inner nuclear layer and in type II cells in the ganglion cell layer (Millar et al.: Neurosci. Lett. 61:311-316, '85), and similar to that of most vertebrates. Three days before hatching, a third population of weakly immunoreactive cells (type III cells) appeared within the inner nuclear layer. The onset of localizable ChAT-IR occurred in amacrine cells and in their processes, before the period of synaptogenesis. Acetylcholinesterase activity was localized at an earlier age than ChAT-IR, and at all ages was present in more cells. The results obtained support the view that "displaced" cholinergic amacrine cells begin to differentiate at the same time and in the same retinal region as type I cholinergic cells. Separation of the two groups is a consequence of the ramification of processes of amacrine and ganglion cells rather than a result of the secondary migration of cells between layers.

Acetylcholinesterase↗
PubMed1987

Laxatives after hemorrhoidectomy.

Thirty patients undergoing a standard Milligan-Morgan hemorrhoidectomy were used for a randomized study of the addition of postoperative laxatives or wheat fiber to the diet. Seventeen patients received wheat fiber; 13 were given a laxative regime of sterculia, magnesium sulfate, and mineral oil. There were no differences between the two groups in preoperative or postoperative bowel habits. Patients receiving wheat fiber had a shorter postoperative hospital stay four days (three to five) vs. five days (three to six), median (range), P less than .01, and suffered less pain after defecation on the day of discharge from the hospital (P less than .05). Fecal leakage or soiling was seen less frequently with wheat fiber than in patients receiving the laxative regime (5/17 vs. 10/13, P less than .05). The authors conclude that wheat fiber added to the diet will produce a satisfactory bowel habit after hemorrhoidectomy, with a lower incidence of fecal leakage and reduced pain after defecation than the usual laxative regime.

Cathartics↗
PubMed1987

Cholinergic amacrine cells of the chicken retina: a light and electron microscope immunocytochemical study.

Cholinergic amacrine cells of the chicken retina were detected by immunohistochemistry using an antiserum against affinity-purified chicken choline acetyltransferase. Three populations of cells were detected: type I cholinergic amacrine cells had cell bodies on the border of the inner nuclear and inner plexiform layers and formed a prominent laminar band in sublamina 2 of the inner plexiform layer, while type II cholinergic amacrine cells had cell bodies in the ganglion cell layer, and formed a prominent laminar band in sublamina 4 of the inner plexiform layer. Type III cholinergic amacrine cell bodies were located towards the middle of the inner nuclear layer, and their processes were more diffusely distributed in sublaminas 1 and 3-5 of the inner plexiform layer. Type I and type II cells were present at densities of over 7000 cells/mm2 in central areas declining to less than 2000 cells/mm2 in the temporal retinal periphery. The cells were organized locally in a non-random mosaic, with regularity indices ranging from 3 peripherally to over 5 centrally. Neither at the light nor electron microscopic levels was a lattice of cholinergic dendrites of the kind reported by Tauchi and Masland [J. Neurosci. 5, 2494-2501 (1985)] detectable. Within the two prominent dendritic plexuses, a major feature of the synaptic interactions of the type I and type II cholinergic cells was extensive synaptic interaction between cholinergic processes. Apart from this, there was little, if any, input to cholinergic processes from non-cholinergic amacrine cells, but there was input from bipolar cells. Output from the cholinergic amacrine cell processes was directed towards non-cholinergic amacrine cells as well as other cholinergic amacrine cells, and ganglion cells.

Animals↗
PubMed1987

Pancreatic responses to endogenous and exogenous gastrin in the dog.

Serum gastrin and pancreatic secretion were measured in conscious Thomas fistula dogs during infusion of increasing doses of porcine gastrin, against a background of secretin. Dose-response relationships were calculated for the effects of gastrin on pancreatic secretion. Gastrin release was also measured after a test meal and after vagal stimulation with 2-deoxyglucose. Peak serum gastrin levels after these stimuli were less than the serum gastrin level associated with the minimal effective dose of gastrin. From the dose-response relationship of serum gastrin and pancreatic protein output, it was possible to calculate the protein output corresponding to the peak gastrin levels after 2-deoxyglucose or a meal. These were equivalent to 20-30% of the observed protein response to these stimuli. We conclude that gastrin plays at most a small part in the stimulation of pancreatic secretion after a meal and in response to 2-deoxyglucose. We also found that truncal vagotomy reduces pancreatic sensitivity to gastrin.

Animals↗