Search PubMed⌕ Search

Biomedical subjects

S Peters

Publications and source records attributed to S Peters.

At least 199 records · Page 11Linked to original sources
PubMed1993

Light- and electron microscopical studies of interstitial cells of Cajal and muscle cells at the submucosal border of human colon.

BACKGROUND: It has been suggested that interstitial cells of Cajal (ICC) at the submucosal border of the colonic circular muscle are pacemaker cells. We studied smooth muscle cells and ICC at the submucosal surface of the circular muscle layer of the normal human colon. EXPERIMENTAL DESIGN: Resected, unaffected specimens from human colon were studied by light microscopy and transmission electron microscopy. RESULTS: Throughout the colon, the inner fourth of each circular-muscle lamella was covered with a layer of 2 to 15 muscle cells (ICMC) with a smaller diameter, more perinuclear organelles, and a greater glycogen content than the outer circular muscle cells. ICMC were interconnected by adherens junctions and close appositions. Small bundles of ICMC were present in the submucosa. ICC were identified in all regions of the colon (ascendens, transversum, and sigmoideum) at the submucosal border, in deeper parts of the submucosa in close contact with smooth muscle bundles as well as in the circular muscle and main septa. ICC had a continuous basal lamina, caveolae, dense bands, thin and intermediate filaments, dense bodies and a well-developed smooth endoplasmic reticulum. Mitochondria and granular endoplasmic reticulum were very abundant. Lipid droplets and glycogen granules were frequent. Thick (myosin) filaments were absent. Close contacts to nerves and gap junctions to other ICC or smooth muscle cells were exceptional. Fibroblast-like cells in the submucosa were rich in granular endoplasmic reticulum and intermediate filaments. They had few dense bands and caveolae. Mitochondria, smooth cisternae and glycogen granules were sparse, cytoplasmic dense bodies and a continuous basal lamina were lacking. Fibroblast-like cells were associated closely with collagen bundles and they had no close contacts with nerves, ICC or muscle cells. CONCLUSIONS: Throughout the normal human colon, submucosal ICC and ICMC are identified and distinguished from other cell types present. Their organization and cytology differ from that of other animal species. The ultrastructure of ICC and ICMC is compatible with important regulatory functions on the circular muscle in the entire human colon.

Aged↗
PubMed1992

Risk assessment in nonischemic ventricular arrhythmia by left and right ventriculography.

Ventricular fibrillation and sudden death are rare phenomena in nonischemic ventricular arrhythmia, particularly in arrhythmogenic right ventricular cardiomyopathy. In most instances electrophysiologic studies help to assess the risk of sudden death, but sometimes programmed ventricular stimulation is unsuccessful. Among 48 patients with ventricular fibrillation (n = 9) and sustained (n = 25) and nonsustained (n = 19) ventricular tachycardia, invasive and noninvasive diagnostic tests (coronary angiography, biventricular angiography, programmed ventricular stimulation, and echocardiography) were performed to obtain more information about the underlying heart disease. In 43 patients (90%) arrhythmogenic right ventricular cardiomyopathy was diagnosed with segmental hypokinesia (n = 31) and diffuse hypokinesia (n = 12) of the right ventricle. In patients with documented ventricular fibrillation, the right ventricular ejection fraction was lower (30.8% vs 47.8% and 45.9%, respectively) and multisegmental contraction impairment of the right ventricle was significantly more frequent (p less than 0.001). Additional left ventricular abnormalities and right ventricular dilatation were not significant parameters for identifying high-risk patients. In addition to programmed ventricular stimulation, quantitative analysis of the results of right and left ventricular angiography contributes to risk assessment in patients with nonischemic ventricular arrhythmia.

Adult↗
PubMed1990

Morphological detection and quantification of lipoprotein(a) deposition in atheromatous lesions of human aorta and coronary arteries.

Lipoprotein(a), as an atherogenic particle, represents an independent risk factor for coronary heart disease. In the present study the morphological distribution of apoprotein (a) and apoprotein B within the arterial wall is described. Apoprotein B, a constituent of very low-density lipoprotein, low-density lipoprotein and lipoprotein(a) has previously been demonstrated in atheromatous lesions. Lipoprotein(a) possesses an additional protein, designated apoprotein (a). Autopsy material (n = 74) from the left coronary artery and from the thoracic aorta has been examined by means of immunohistochemistry and both apoprotein (a) and apoprotein B were detected, primarily associated with the extracellular matrix and accumulating in lesions in the arterial wall. The staining pattern for both antigens was almost always found to be congruent, suggesting that the detection of (a)-antigen has to be attributed at least in part to the presence of lipoprotein(a). It is concluded that both low-density lipoprotein and lipoprotein(a) have an important role in the pathogenesis of atherosclerosis.

Adolescent↗
PubMed1990

A comparison of enprofylline and theophylline in the maintenance therapy of chronic reversible obstructive airway disease.

To compare the efficacy and side effects of two xanthine derivatives in the maintenance therapy of reversible obstructive airway disease, 242 patients were assigned in randomized, double-blind fashion to receive either oral enprofylline or theophylline for 5 weeks in addition to their usual maintenance regimens. After a week of placebo xanthine therapy, enprofylline-treated patients received 150 mg of this drug twice daily (b.i.d.) for 3 days, 300 mg b.i.d. for 2 weeks, and 450 mg b.i.d. for 2 weeks. Theophylline was administered in identical doses, except that the final dosage increase was not made if plasma theophylline was 12 mg/ml or higher. At 300 mg b.i.d., both drugs significantly increased morning peak expiratory flow rate (PEFR), the mean increase above baseline being significantly higher for theophylline-treated patients (29.9 +/- 37.2 L/min) than for enprofylline-treated patients (17.4 +/- 36.9 L/min) (p = 0.023). At 450 mg b.i.d., improvement in morning PEFR was not significantly different between theophylline-treated (31.5 +/- 44.4 L/min) and enprofylline-treated groups (23.5 +/- 48.4 L/min). Evening PEFR, FEV1, and asthma symptom scores also improved significantly, demonstrating no significant difference between groups. The incidence of side effects was also similar between groups. We conclude that both enprofylline and theophylline offer useful bronchodilatation in the maintenance therapy of asthma, enprofylline, 450 mg b.i.d., being approximately equivalent to theophylline, 300 or 450 mg b.i.d.

Adolescent↗
PubMed1990

Coronary artery bypass surgery in Canada.

This report examines trends in the number and the rates of coronary artery bypass surgery (CABS) in Canada, performed over a six-year period from 1981-82 to 1986-87. The analysis includes comparisons of rates and events by sex, age and geographic location. In Canada 10,865 CABS were performed in 1986-87 representing a 39% increase over 1981-82. During the same period the rate of CABS rose to 43.2 per 100,000 population. In the twelve census metropolitan areas (CMAs) covered in this study, CABS increased 45.7% from 6,477 in 1981-82 to 9,439 in 1986-87, while hospital separations for Ischemic Heart Disease (IHD) increased by 22.6%. Regionally the coronary artery bypass surgery rate was lowest in Halifax at 62.4 per 100,000 population and highest in Ottawa-Hull at 131.8 per 100,000 population. The average annual proportion of CMAs ranged from 15.5% for residents in Halifax (84.5% for non-residents) to a high of 65.7% for residents in Montreal (34.3% for non-residents). Procedure rates increased consistently among the 65-74 and 75+ age groups, remained stable in the 55-64 age group, and decreased in the 35-54 age group. The variations among the CMAs may in part be due to the amount of resources available in each CMA, the demand for this type of service and perhaps to differing patterns of physician practice.

Adult↗
PubMed1990

Assessment of in vivo activated T cells in patients with Crohn's disease.

Besides clinical indices, acute phase reactants and measurement of permeability of the gut immunological parameters have been proposed for assessment of clinical activity in Crohn's disease (CD). The latter refers in particular to the number of activated peripheral T cells (APT) which are found to be increased in patients with CD and ulcerative colitis. Further analysis of the subset of APT revealed that in CD their number is correlated to the histopathological ratings and the number of activated T cells of the affected mucosa. A major subset of APTs in CD and ulcerative colitis expresses receptors for IgA (Fc-alpha-R). This T cell subset seems to be characteristic of patients with inflammatory bowel diseases, exhibiting a specificity of 88% and a sensitivity of 92% for CD as compared with non-inflammatory bowel diseases. Methodological complexity turned out to be the major disadvantage of assessment of APT and their subsets.

Adolescent↗
PubMed1990

[Embolectomy in fulminant lung embolism and persistent electromechanical uncoupling--a case report and review of the literature].

A 56-year-old patient with deep vein thrombosis shown by phlebography developed a massive pulmonary embolism during perfusion ventilation lung scanning with complete occlusion of the main pulmonary artery branch. 40 minutes after beginning of symptoms the patient suffered from persistent heart failure. Under external heart massage and controlled ventilation a cardio-pulmonary bypass was established after sterniotomy. After manual manipulations to express peripheral emboli pulmonary embolectomy and cava clipping was performed. The patient recovered without neurological damage.

Cardiopulmonary Bypass↗
PubMed1989

[Saliva--the undervalued protection system (2)].

This work gives a comprehensive overview of the repair and defence capacity of saliva. The separate chapters deal with the production and composition of the mouth fluid, with its chemical characteristics as well as its mechanical, chemical and biological functions. Pointers to the practical uses of the knowledge presented conclude the work.

Dental Caries↗
PubMed1989

[Putting to the proof three-unit bonded bridges in practice].

Control data of 52 three-unit bonded bridges were evaluated to verify the clinical value of an expanded treatment concept. With a total of 10% failures (5 loose retainers) after 45 months the results demonstrated that this concept involving the integration of cavities into the retainer design, the insertion of bonded bridges at an advanced age or into the posterior area, and the combination with crowns provides successful treatment alternatives in acid etched cast prosthodontics.

Adolescent↗