Search PubMed⌕ Search

Biomedical subjects

K Lewin

Publications and source records attributed to K Lewin.

At least 37 records · Page 2Linked to original sources
PubMed1988

Observer variation in the diagnosis of dysplasia in Barrett's esophagus.

The potential value of biopsy surveillance of patients with Barrett's esophagus for dysplasia is diminished by a lack of agreement on the diagnostic criteria for dysplasia. In a preliminary consensus conference, experienced gastrointestinal pathologists from four medical centers agreed on criteria for a five-tiered histologic classification of dysplasia in Barrett's esophagus--negative for dysplasia, indefinite for dysplasia, low-grade dysplasia, high-grade dysplasia, and intramucosal carcinoma. Eight morphologists in the four centers tested the criteria for interobserver agreement by examining a set of coded slides that had been chosen to include some especially difficult interpretative problems in all five histologic classifications. Interobserver agreement of 85 and 87% was achieved in successive reviews when the combined group of high-grade dysplasia and intramucosal carcinoma was compared with the combined group of low-grade dysplasia, indefinite for dysplasia, and negative for dysplasia. Comparison of other groups yielded less agreement. For example, negative for dysplasia could be distinguished from all other diagnoses with an interobserver agreement of 72%. We conclude that experienced gastrointestinal morphologists can diagnose high-grade dysplasia and intramucosal carcinoma with a high degree of agreement and thus can detect those patients who may need immediate rebiopsy or esophageal resection. Either further refinement of histologic criteria or alternate diagnostic methods will be needed to achieve the reproducible diagnosis of indefinite changes and low-grade dysplasia. This is important because patients with such changes theoretically merit closer endoscopic surveillance.

Barrett Esophagus↗
PubMed1987

AIDS: an overview of the pathology.

This article reviews the findings at postmortem examination on AIDS and separately details the surgical pathology of the gastrointestinal tract, liver, lymph nodes, and skin in these patients. Emphasis is placed upon the light microscopic features of the specimens commonly received in surgical pathology so as the promote the ready diagnosis of this important and grave disorder.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Carcinoid tumors and the mixed (composite) glandular-endocrine cell carcinomas.

Carcinoid tumors display a wider histologic spectrum than was previously thought. Some tumors may show atypical features such as glandular profiles, a spindle cell pattern, squamous or osteoid metaplasia, or pleomorphism. In rare cases they may be poorly differentiated and resemble undifferentiated carcinoma or lymphoma. As is well known, some carcinoids are associated with well-defined syndromes, such as the carcinoid or the Zollinger-Ellison syndrome, due to the secretion of amines or peptides. Immunohistochemical analysis of these tumors, however, has shown that whereas one amine or peptide may predominate, most are multihormonal. These findings are also seen with the clinically silent tumors such as the foregut and hindgut carcinoids. Furthermore, the immunohistochemically demonstrated amines and peptides in the primary tumor do not necessarily correspond to those normally found in the overlying endocrine cells. An increasing number of tumors have recently been described which contain an admixture of neoplastic endocrine and nonendocrine epithelial cells. Thus, the classification of gut mucosal tumors into carcinomas and endocrine tumors has had to be modified to include those tumors which have been designated as mixed or composite tumors. These have been further subdivided into several distinctive histologic types. Some of these tumors, such as the microglandular-goblet cell carcinomas, have a distinctive clinical behavior, whereas others, such as the adenoendocrine cell carcinomas, appear to behave in a manner similar to adenocarcinoma. Additionally, there is another tumor type, namely the amphicrine tumor, which differs from the mixed tumors in that endocrine and epithelial cell constituents are present within the same cell.

Aged↗
PubMed1986

Late obstruction of the lateral ileal reservoir after colectomy and endorectal ileal pullthrough procedures.

During a period of eight years, 19 of 83 patients underwent colectomy, mucosal proctectomy and endorectal ileal pull-through procedures with isoperistaltic ileal reservoir for ulcerative colitis or polyposis. These patients had late obstruction of the ileal reservoir develop which lead to distension, stasis, reservoir inflammation and diarrhea. In nine patients, the reservoir obstruction as due to a lengthy rectal muscle canal and a longer distance from the lower end of the reservoir to the anus than was optimal, causing angulation and obstruction. Surgical division of the upper rectal muscle and retraction of the reservoir further into the pelvis combined with resection of the elongated upper end of the ileal reservoir were followed by relief of symptoms in every patient. Five patients had intestinal adhesions develop necessitating resection of a segment of the upper ileal reservoir. Five other patients had obstruction develop from an internal hernia; each required resection of the redundant upper portion of the reservoir. Each of the patients was relieved of diarrhea and gaseous distension after the obstruction was corrected and the ileal reservoir was shortened. The optimal length of ileal reservoir is approximately 10 to 15 centimeters for children and 18 to 22 centimeters for adults. Resection of all except 5 to 7 centimeters of rectal muscle cuff and placement of the lower end of the ileal reservoir within 3 to 5 centimeters of the ileoanal anastomosis appeared to reduce substantially the incidence of reservoir obstruction. Reservoir obstruction has not been observed in the last 37 patients who have undergone operation.

Adolescent↗
PubMed1984

Biochemical and immunohistochemical characterization of proteins in Hürthle cell carcinoma.

The present study reports the biochemical and immunohistochemical findings in the cytosol of a Hürthle cell carcinoma as compared with that of normal thyroid tissue. Sephadex G-200 chromatography of the extract derived from a Hürthle cell carcinoma and from normal thyroid tissue revealed three identical pools. Pool I consisted mainly of thyroglobulin (Tg), pool II corresponded to albumin, while pool III contained unidentified low molecular weight fragments which could not be studied further. Hürthle cell carcinoma, pool I, had a Tg content of 12.9 micrograms Tg/mg equivalent tissue and a 127I content of 5,6 mole/mole of Tg. Its sialic acid content was undetectable, however. In pool I of the normal thyroid gland, the respective values were 62.8 micrograms Tg/mg equivalent tissue, 21.3 +/mole 127I/mole Tg, and 15.4 mole sialic acid/mole Tg. The albumin contained in both pools II was shown to be ioidinated at the following levels: 0.025 mole 127I/mole albumin in Hürthle tumor pool II vs 1.28 mole 127I/mole albumin in normal thyroid pool II. Immunohistochemical studies confirmed the presence of Tg and albumin in the malignant Hürthle cells and acini and colloid. Thus, Hürthle cell carcinoma contained Tg and albumin. The Tg content was five times less compared with control tissue. Both proteins (Tg and albumin) were poorly iodinated in Hürthle carcinoma tissue, and the iodination of albumina seemed to be more severely impaired. The site of synthesis of both proteins could not be derived from the present studies.

Carcinoma↗
PubMed1983

Beneficial effect of pancreatic polypeptide in experimental pancreatitis.

Two animal models have been employed to examine the role of pancreatic polypeptide, a potent and selective inhibitor of pancreatic exocrine secretion, in the treatment of acute pancreatitis. In one model pancreatitis was induced by feeding young female Swiss Webster mice an ethionine-supplemented, choline-deficient diet for 48 hr. Animals (N = 30 per group) were injected subcutaneously every 8 hr for 7 days with pancreatic polypeptide (0, 2, 20, and 200 micrograms/kg/day). Treatment with 20 and 200 micrograms/kg/day pancreatic polypeptide significantly (P less than 0.05) reduced mortality from a control rate of 70% to 42% and 33%, respectively. Treated animals also exhibited significant (P less than 0.05) decreases in pancreatic content of activated chymotrypsin and an improvement in pancreatic histology. Pancreatic polypeptide was effective whether treatment was started before or at the same time the test diet was introduced. In contrast, pancreatic polypeptide failed to protect dogs with acute pancreatitis induced by retrograde injection of the pancreas with bile, which may reflect the rapid and mechanical nature of pancreatic damage in this animal model.

Animals↗
PubMed1983

Effects of prostaglandin and indomethacin on diet-induced acute pancreatitis in mice.

This study was performed to determine the effects of exogenous prostaglandin and a prostaglandin synthetase inhibitor on experimental pancreatitis in mice. An ethionine-supplemented choline-deficient diet was used to induce pancreatitis in 4-6-wk-old Swiss Webster mice. Mice were injected subcutaneously with 16,16-dimethyl prostaglandin E2 (0.1, 1.0, 10 micrograms X kg-1 X day-1), indomethacin (0.05, 0.5, 5 mg X kg-1 X day-1), or saline for 7 days. The ethionine-supplemented choline-deficient diet was introduced 24 h after the first injection, and animals ate the test diet for 48 h. A 55% mortality was observed in control animals (n = 100) treated with carrier alone. Treatment with 10 micrograms X kg-1 X day-1 of 16,16-dimethyl prostaglandin E2 significantly decreased (p less than 0.01) mortality to 12% (n = 100). Improved survival was accompanied by a significant (p less than 0.05) decrease in the pancreatic content of free chymotrypsin and a decrease in histologic damage. Treatment with 5 mg X kg-1 X day-1 of indomethacin (n = 30) significantly (p less than 0.01) increased mortality in diet-treated rats from a control rate of 55% to 100%. These studies demonstrate a protective effect of prostaglandin on the pancreas and suggest a role for endogenous prostaglandins in the pathophysiology of pancreatitis.

16,16-Dimethylprostaglandin E2↗
PubMed1983

Reliability of antenatal testing: estriol levels versus nonstress testing.

During the third trimester of pregnancy, 334 high-risk patients were followed with antenatal fetal heart rate (FHR) evaluation and with serial determinations of unconjugated plasma estriol. The antenatal FHR tests included nonstress testing (NST) and investigation of beat-to-beat variability. Data indicate that the NST was more reliable than estriol analysis in assessing fetal compromise. While predictive values of negative test results did not differ statistically, the NST/beat-to-beat assessment was particularly accurate in identifying fetal jeopardy in more than 45.0% of the fetuses at risk, whereas only 22.8% cases of jeopardy were accurately predicted by abnormal estriol values. An abnormal NST with loss of beat-to-beat FHR variability should therefore take precedence over plasma estriol determinations during antenatal surveillance of high-risk obstetric patients.

Estriol↗
PubMed1980

Effects of gastrointestinal polypeptides on hormone content of endocrine pancreas in the rat.

Although trophic actions of gastrointestinal peptides on exocrine pancreas have been shown, little is known regarding their effects in endocrine pancreas. Therefore, we measured the contents of somatostatin-like immunoreactivity (SLI), insulin and glucagon, in pancreatic extracts from rats that had been treated three times a day for 10 days with saline; 1 microgram/kg caerulein; 5, 25, and 100 microgram/kg secretin; 1 microgram/kg caerulein plus 5, 25, and 100 microgram/kg secretin; 25 microgram/kg pancreatic polypeptide; 15 microgram/kg glicentin; or 15 microgram/kg gastric-inhibitory polypeptide. Pancreatic SLI content was significantly increased in rats treated with glicentin and caerulein plus secretin at the two higher doses. No difference was noted between the control and the caerulein plus 100 microgram/kg secretin groups in delta-cell number per islet when examined by the immunoperoxidase technique. These data suggest that because of their effect on SLI content gastrointestinal polypeptides may modulate pancreatic endocrine function.

Animals↗
PubMed1979

Improvement of the glucose oxidase immunoenzyme technic. Use of a tetrazolium whose formazan is stable without heavey metal chelation.

Glucose oxidase immunoenzymatic localization provides a simple way to show antigens in mammalian tissues, with no need for the quenching of endogenous nonspecific staining. The method is useful for the demonstration of many antigens in formalin-fixed, paraffin-embedded tissues. Improvement of this technic by the use of p-nitro blue tetrazolium chloride (NBT) as the disclosing reagent provides a stable, finely grained localization not possible with the previously used thiazolyl blue (MTT). The described modification makes available an ideal immunoenzymatic stain for the study of tissues at the level of the light microscope. This stain is especially useful for the examination of tissues with hemorrhagic or inflammatory lesions, since there is no endogenous background staining. Slides are permanent, and the technic can be used with peroxidase-labeled antibody to localize two antigens in the same tissue.

Animals↗
PubMed1979

Isolation of histamine-containing cells from canine fundic mucosa.

The cells of the fundic portion of canine gastric mucosa were dispersed by collagenase digestion and separated into fractions by sequential use of velocity sedimentation in an elutriator rotor followed by a density gradient separation. There was a close correlation between histamine content and number of mast cells in the different cell fractions. The mast cells possessed characteristic dense granules, which stained metachromatically, but did not release histamine on exposure to Compound 48/80. The most highly purified fractions contained 80% mast cells and a histamine content of 2.5 pg/mast cell.

Animals↗
PubMed1977

Rapid intubation with fazadinium and suxamethonium.

Fazadinium at two dose levels (1 mg/kg and 1.5 mg/kg) and suxamethonium at three dose levels (50 mg, 75 mg and 100 mg) were investigated in 106 adult patients to determine the time interval from injection to tracheal intubation. The intubating conditions were graded according to the scheme described by Lund and Stovner. Suxamethonium 100 mg gave the shortest time interval between the end of injection and intubation. There was no significant difference between the intubation time when smaller doses of suxamethonium (50 mg and 75 mg were used and those when AH8165 (1 mg and 1.5 mg/kg) were given. Suxamethonium 100 mg also produced a significantly higher incidence of excellent intubating conditions. The clinical implications of the findings are discussed.

Adult↗
PubMed1976

Unilateral medullary sponge kidney: cause of persistent bacteriuria.

A patient with twenty years of persistent bacteriuria secondary to unilateral medullary sponge kidney, and in whom no antibiotic would sterilize the urine, was cured of her infection by nephrectomy in the presence of contralateral hydronephrosis. A review of the literature shows 23 cases of unilateral medullary sponge kidney in which nephrectomy or partial nephrectomy was apparently equally successful, although no bacteriologic follow-up data are given.

Bacteriuria↗
PubMed1976

Stimulation of the peripheral chemoreceptors with sodium bicarbonate.

The i.v. administration of sodium bicarbonate was found to cause an increase in arterial pH, followed by an increase in PaCO2. This caused a large increase in lung ventilation in in PaO2. Oxygen administration in human subjects, and anatomical denervation of the chemoreceptors in dogs, caused a substantial delay in the ventilatory responses to sodium bicarbonate. It was concluded that the i.v. administration of sodium bicarbonate provides a method of testing the presence of peripheral chemoreflexes which has the advantage of being independent of alveolar ventilation.

Adult↗
PubMed1975

Operating room air pollution: influence of anaesthetic circuit, vapour concentration, gas flow and ventilation.

Atmospheric halothane was sampled from three selected operating theatres and anaesthetic rooms during the middle of operating sessions. Two of the operating theatres studied were ventilated with total air exchange once every six minutes; the third operating theatre had no ventilation. End-tidal samples were obtained from anaesthetists. Halothane vapour concentrations were analysed by gas-liquid chromatography. The effect of commonly used anaesthetic circuits on the level of contamination in the ambient atmosphere was studied. Concentrations of halothane vapour in the theatre atmosphere were found to vary with sampling site, anaesthetic circuit used, total gas flow and vapour concentration, the scavenging system employed and the efficiency of ventilation system. Although the ventilation system considerably reduced the level of halothane in the operating room atmosphere, it did not totally eliminate the contaminating vapour. A significant reduction in operating-room pollution was obtained by use of simple scavenging equipment. Scavenging of anaesthetic vapours outside the operating room led to 97.3 per cent reduction of overall mean concentration of halothane in the operating room atmosphere and reduction of 72 per cent in end-tidal samples of anaesthetists, with the Magill semiclosed circuit. The implications of these findings are discussed.

Air↗
PubMed1973

The response to prednisolone in atrophic gastritis: a possible effect on non-intrinsic factor-mediated vitamin B 12 absorption.

The administration of prednisolone did not affect absorption of vitamin B(12) and gastric secretion of intrinsic factor in nine subjects with normal gastric mucosa, or in five with chronic superficial gastritis. No gastric morphological changes were observed in either group. In contrast, four of seven patients with pernicious anaemia showed improvement in absorption of vitamin B(12) during prednisolone administration for periods of two to 10 months. No consistent changes in gastric mucosal morphology were noted. An additional five patients were studied intensively during one month of prednisolone administration. In three, absorption of vitamin B(12) was restored to within the normal range between eight and 13 days after the commencement of the drug. The improvement was not paralleled by enhancement of secretion of intrinsic factor or other vitamin B(12) binders. Suppression of intrinsic factor antibodies in serum and gastric juice did not occur consistently in those patients showing a functional response.

Anemia, Pernicious↗