PubMed Health⌕ Search

Biomedical subjects

C Hermans

Publications and source records attributed to C Hermans.

At least 73 records · Page 4Linked to original sources
PubMed1997

Algorithm analysis of lectin glycohistochemistry and Feulgen cytometry for a new classification of nasal polyposis.

The aim of this study is to present a new classification of nasal polyps. This classification is based both on morphologic criteria relating to morphonuclear features from isolated Feulgen-stained nuclei and on glycohistochemical characteristics from histologic slides submitted to three lectins (peanut, wheat germ, and gorse seed agglutinins) and one neoglycoconjugate glycohistochemical stain. While the morphonuclear features (including 30 variables) relate essentially to chromatin pattern, the glycohistochemical stains (including 16 variables) are linked to the presence of specific carbohydrate moieties in cell membranes and cytoplasm. Forty-nine nasal polyps, including single polyps, diffuse polyposis, cystic fibrosis-related polyposis, and aspirin idiosyncracy-related polyposis associated with asthma, were thus characterized. All the variables were obtained quantitatively by means of computer-assisted microscopy. Two complementary methods of data classification were used to determine the actual diagnostic value contributed by each quantitative variable, namely, discriminant analysis, which forms part of multifactorial statistical analysis, and the decision tree technique, which is an artificial intelligence-related algorithm. The data so obtained show that our morphologic classification of nasal polyps fits in with the classification of nasal polyps defined on the basis of clinical criteria.

Algorithms↗
PubMed1996

Hypocalcaemia and chronic alcohol intoxication: transient hypoparathyroidism secondary to magnesium deficiency.

The authors report the observation of an alcoholic patient admitted for tetanic manifestations, in whom severe hypocalcaemia associated with hyperphosphatemia were suggestive of hypoparathyroidism. Administration of magnesium supplementation alone improved the clinical features and led to the correction of the calcium abnormalities. The mechanisms of hypomagnesemia in alcohol intoxication are reviewed as well as the links with hypocalcaemia.

Aged↗
PubMed1996

Case report: 17 alpha-hydroxylase/17,20-lyase deficiency: a rare cause of endocrine hypertension.

The combination of hypertension, hypokaliemia, and male pseudohermaphroditism or amenorrhea must prompt a search for a rare adrenal enzymatic defect, 17 alpha-hydroxylase/17,20-lyase deficiency. This is a report of the observation of a male patient in whom this rare deficit was diagnosed in adulthood on the basis of lifelong ambiguous external genitalia, hypogonadism, severe hypertension, bilateral adrenal hyperplasia, and biological markers evoking an excess of mineralocorticoids without hyperaldosteronism.

Adrenal Gland Diseases↗
PubMed1995

Cosmid contigs from the tuberous sclerosis candidate region on chromosome 9q34.

Tuberous sclerosis (TSC) is a heterogeneous multisystem disorder with loci on 9q34 (TSC1) and 16p13.3 (TSC2). The TSC2 gene has recently been isolated, while the TSC1 gene has been mapped to a 5-cM region between the markers D9S149 and D9S114. In our effort to localise and clone TSC1, we have obtained three adjacent cosmid contigs that cover the core of the candidate region. The three contigs comprise approximately 600 kb and include 80 cosmids, 2 P1 clones, 1 YAC, 5 anonymous markers and 4 sequence-tagged sites. The ABO blood group locus, the Surfeit gene cluster, the dopamine beta-hydroxylase gene (DBH) and VAV2, a homologue of the vav oncogene, have all been mapped within the contigs. Exon trapping and mutation screening experiments, aimed at identifying the TSC1 gene, are currently in progress.

Bacteriophage P1↗
PubMed1993

Combined thromboxane A2 synthase inhibition and prostaglandin endoperoxide receptor antagonism limits myocardial infarct size after mechanical coronary occlusion and reperfusion at doses enhancing coronary thrombolysis by streptokinase.

OBJECTIVES: We sought to examine to what extent a combination of strong thromboxane A2 synthase inhibition and moderate endoperoxide receptor blockade enhances streptokinase-induced coronary thrombolysis and provides anti-ischemic activity independent from its thrombolytic activity. METHODS: Coronary thrombi, induced by crush injury and stenosis of the coronary artery, were lysed with streptokinase, 10,000 IU/kg body weight over 90 min, in anesthetized dogs receiving solvent (n = 11), ridogrel, 0.31 mg/kg intravenously, for thromboxane A2 synthase inhibition (n = 7) or ridogrel, 5 mg/kg, for additional prostaglandin endoperoxide receptor antagonism in addition to thromboxane A2 synthase inhibition (n = 7) 10 min before the administration of streptokinase. RESULTS: Thrombolytic efficacy was greatest in animals receiving both dual-acting ridogrel, 5 mg/kg intravenously, and streptokinase as evidenced by the highest incidence of high grade coronary reperfusion (solvent 3 of 11; ridogrel, 0.31 mg/kg, 5 of 7; ridogrel, 5 mg/kg, 7 of 7; p < 0.05 vs. solvent) within the shortest delay (solvent 210 min; ridogrel, 0.31 mg/kg, 85 min; ridogrel, 5 mg/kg, 37 min; p < 0.05 vs. solvent and ridogrel, 0.31 mg/kg) and the lowest incidence of reocclusion (solvent 5 of 7; ridogrel, 0.31 mg/kg, 2 of 7; ridogrel, 5 mg/kg, 1 of 7; p < 0.05 versus solvent). Myocardial infarct size after coronary artery ligation (90 min) and subsequent reperfusion (150 min) in anesthetized dogs was 49.3 +/- 4.3% versus 29 +/- 3.9% (p < 0.05 vs. solvent) of the area of the left ventricle at risk in dogs receiving solvent (n = 9) or ridogrel, 5 mg/kg intravenously (n = 10), respectively, despite similar hemodynamic characteristics, collateral blood flow and area at risk in both groups. CONCLUSIONS: Combined thromboxane A2 synthase inhibition and endoperoxide receptor antagonism 1) upgrades thrombolysis with streptokinase in canine coronary arteries, 2) limits myocardial infarct size after nonthrombotic coronary occlusion and reperfusion, and 3) may preserve ventricular function compromised by coronary occlusion through dual manipulation of the arachidonic acid cascade in blood and myocardial tissue, respectively.

Animals↗
PubMed1993

Interplay between platelet-derived 5-hydroxytryptamine and arachidonic acid metabolites limits the thrombolytic efficacy of streptokinase against canine platelet-rich coronary thrombosis.

The comparative contributions of arachidonic acid (AA) metabolites and 5-hydroxytryptamine (5-HT) to the delay of reperfusion and rate of reocclusion after coronary thrombolysis with streptokinase were assessed in dogs using (a) single TXA2 synthase inhibition; (b) single 5-HT2-receptor blockade; (c) dual TXA2 synthase inhibition/PGH2 receptor antagonism; (d) 5-HT2-receptor blockade combined with TXA2 synthase inhibition; and (e) 5-HT2-receptor blockade combined with dual TXA2 synthase/PGH2-receptor antagonism. In open-chest anesthetized dogs, occluding coronary thrombi were induced by severe intimal injury in combination with critical artery stenosis. Fifty minutes after occlusive thrombus formation, the animals received intravenously (i) saline (S); (ii) ketanserin, 0.3 mg/kg (K), a 5-HT2-receptor antagonist; (iii) ridogrel, either at a low dose 0.3 mg/kg (R 0.3), exerting single TXA2 synthase inhibition; or (iv) at 5 mg/kg (R 5), exerting additional TXA2/PGH2-receptor antagonism; or (v) the combination of either dose of ridogrel with ketanserin. Ten minutes later, all dogs received streptokinase (SK; 1,000 IU/kg i.v. + 100 IU/kg/min i.v. infusion for 90 min). High-grade thrombolysis (> or = 50% coronary reperfusion vs. prethrombosis value as assessed by flow measurements) with SK occurred in 3/11 dogs treated with S, in 5/7 with R 0.3 and K, and in 7 of 7 dogs in the other medication groups; this occurred within > or = 55 min with S, R 0.3, and K, within 37 +/- 12 min with R 5 (p < 0.05 vs. solvent and R 0.3), and within 38 +/- 5 and 23 +/- 5 min with R 0.3 + K and R 5 + K, respectively (p < 0.05 vs. S, R 0.3, and K). The occurrence of reocclusion within 120 min after the cessation of SK administration was significantly reduced in all treatment groups, except K. That of cyclic flow reduction was reduced by R 5, R 0.3 + K, and R 5 + K. The peak extent of coronary reperfusion was highest in the K + R groups (S = 33% of preocclusion value; K = 60%; R 0.3 = 68%; R 5 = 76%; K + R 0.3 = 80%, p < 0.05 vs. S; and K + R 5 = 89%, p < 0.05 vs. solvent, R 0.3, and K). This study shows that the interplay between AA metabolites and 5-HT is involved in the platelet-dependent reduction in the thrombolytic efficacy of streptokinase in lysing coronary thrombi.

Animals↗
PubMed1992

Seasonality of cattle feed sources in Pabna, Bangladesh.

Cattle feed sources were studied at village level in Pabna district, Bangladesh. A large quantity of feed was offered. In the monsoon the average amount of DM fed to a mature animal of 210 kg was 7.1 kg d-1, consisting of about equal amounts of straw, weeds and leaves. In winter animals grazed for an average of 3.7 hd-1 and were supplemented with 3.9 kg DM d-1 (two-thirds straw). In summer they were offered 5.4 kg DM d-1 (one-third straw and two-thirds weeds and leaves) and they grazed for 0.5 h d-1. The major limiting constraint on cattle production is the quality of the feed offered, particularly in the monsoon period when animals cannot graze. In future, feed quality will become even more of a problem because grazing lands are gradually disappearing.

Animal Feed↗
PubMed1991

Priming solutions for cardiopulmonary bypass: comparison of three colloids.

The present study was designed to compare the differences in the clinical effects of three colloidal solutions, albumin, urea-linked gelatin, and succinyl-linked gelatin, when used as priming fluids for cardiopulmonary bypass (CPB) under alpha-stat conditions. A consecutive series of 105 patients scheduled for cardiac surgery were randomized into three identically managed groups, except for the CPB prime. Variables relating to acid-base status, oncotic activity, metabolism, coagulation, and postoperative evaluation were measured. Marked differences in acid-base status, colloid osmotic pressure, additional prime requirements, blood lactate, urine output, and the need for buffer solutions occurred among groups, with the succinyl-linked gelatin group having better results than the other groups. Changes in hemodynamics, oxygen consumption, and blood-glucose levels during CPB did not vary among groups. There were also no important intergroup differences in hematologic and clotting variables or postoperative parameters such as blood loss or use of blood products. Electrolyte changes were similar except for a significant increase in ionized calcium that occurred in the urea-linked gelatin group after bypass. The results indicate that succinyl-linked gelatin is an adequate and safe alternative to human albumin for use as a colloid during CPB under alpha-stat conditions.

Acid-Base Equilibrium↗
PubMed1991

Evaluation of factors influencing myocardial infarct size in unconscious dogs.

STUDY OBJECTIVE: The aim was to evaluate the factors determining myocardial infarct size in unconscious dogs. DESIGN: In anaesthetised open chest dogs, the left anterior descending coronary artery was occluded either by ligation or by thrombosis for different time periods (1.5 h, 4 h, 24 h), with or without reperfusion. Haemodynamic variables were recorded throughout the experiment. Radioactive microspheres (15 microns) were injected at the end of the ischaemic period to measure regional myocardial blood flow. Infarct size and area at risk were determined by the Evans blue triphenyltetrazolium staining technique followed by planimetry. SUBJECTS: Mongrel dogs of either sex (n = 16-42 per experiment), weight 18-25 kg, were used. MEASUREMENTS AND MAIN RESULTS: A large interindividual variability in infarct size was observed after occlusion of the left anterior descending coronary artery at a standardised location for a well defined period. An examination of the factors responsible for this variability was carried out in order to develop a statistical model which would make it possible to predict infarct size. Using multiple regression analysis, it was found that in most protocols (except 90 min thrombosis) more than 85% of the variability in infarct size could be explained by the size of the area at risk and the amount of collateral flow. Thus, knowing the area at risk and the collateral flow, a fairly accurate prediction can be made of the size of the infarct that the dog will develop after a defined occlusion period. Furthermore, it was found that the infarct size increased with duration of occlusion, while duration of reperfusion had no effect. In the 90 min occlusion group thrombosis induced a larger final infarct than ligature. CONCLUSIONS: A correction for baseline variables is necessary in order to compare infarct size between experimental groups. The usefulness of this procedure is shown by an example of an experimental intervention, i.e., R 56,865, a drug with known cardioprotective effects.

Animals↗
PubMed1991

Effects of R 56,865, a preventer of cellular calcium overload, on left ventricular diastolic properties during pacing-induced ischemia in dogs.

The effects of R 56,865, a compound with unusual calcium antagonistic properties, on altered left ventricular (LV) diastolic properties were studied during pacing-induced ischemia in dogs with coronary stenosis. Severe coronary artery stenosis was produced on both the left anterior descending (LAD) and circumflex (Cx) coronary arteries in anesthetized beta-blocked dogs. The right atrium was paced at 200 beats/min for 3 min. In the post-pacing period and before drug intervention, the most characteristic observation was a significant increase in LV end-diastolic pressure (LVEDP) and in the time constant of (tau) LV pressure decrease; after return of LV hemodynamics to baseline values (15 min), R 56,865 (0.16 mg.kg-1) or solvent (control) was injected and four subsequent pacing runs were performed at 30-min intervals. In the postpacing period of these four subsequent runs, there was a steep increase in LVEDP and tau-values while HR returned more slowly to baseline values. After R 56,865 infusion, the increase in LVEDP and tau-values was significantly lower than in the pretreatment run and all LVEDP values were significantly lower than in the control group. We conclude that R 56,865 effectively attenuates ischemia-induced changes in LV diastolic stiffness.

Animals↗
PubMed1991

Stunned myocardium has increased mitochondrial NADH oxidase and ATPase activities.

Ten anesthetized, open-chest dogs were subjected to occlusion of the left anterior descending coronary artery for 15 minutes, followed by reperfusion for 150 minutes. Hemodynamics were recorded and regional myocardial contraction was measured sonometrically. The hearts were then fixed in situ using glutaraldehyde for cytochemical studies. Systolic wall thickening remained unchanged in the non-ischemic myocardium, but was significantly depressed (stunned) in the area of the left anterior descending coronary artery during reperfusion. NADH oxidase and ATPase activities were very weakly present in mitochondria from non-ischemic myocardium. In the ischemic endocardium, irreversibly injured cells had mitochondria which were severely altered and contained no reaction products to the two enzymes. In contrast, high NADH oxidase and ATPase activities were present in mitochondria from the less severely injured cells of the endocardial zone of stunned areas. Since this zone is particularly susceptible to ischemia in dogs, the high mitochondrial NADH oxidase and ATPase activities may be early signs of ischemic damage, reflecting a disturbance in mitochondrial respiratory activity in stunned myocardium.

Adenosine Triphosphatases↗
PubMed1990

Comparison of two cattle production systems in Pabna district Bangladesh.

In Pabna district, Bangladesh there are two cattle production systems: a draught-oriented system with local Deshi cattle and more milk-oriented production with Pabna Milking Cow (PMC) stock. Deshi animals are smaller than PMC animals. More PMC cows are milked than Deshi cows and the milk off-take of PMC cows is much higher. The calving interval in Deshi cows is one year longer than in PMC cows. The great majority of the bullocks and the bulls are used as draught animals. More than 80% of the Deshi cows also have to work compared with only about half of the PMC cows. The milk off-take of cows used for draught work is 30% less than that of other cows. One of the major differences between the two systems is that PMC cows have access to grazing along the rivers. These areas are increasingly taken up for cropping and the traditional Pabna milk production farming system is gradually being replaced.

Animal Husbandry↗
PubMed1989

Mitochondrial hydrogen peroxide generation by NADH-oxidase activity following regional myocardial ischemia in the dog.

Recently, an exogenous NADH-oxidase has been shown to be a source of oxygen derived toxic species in heart mitochondria. This enzyme uses NADH and oxygen to form superoxide radicals and hydrogen peroxide. Growing evidence suggests that oxygen radicals and hydrogen peroxide may contribute to cardiac damage during ischemia or hypoxia. The activity of the enzyme NADH-oxidase could play an important role in the damage caused by oxygen derived toxic species, especially since cellular defense mechanisms against free radicals are depleted under ischemic conditions. In this study, a cytochemical method was used to visualize hydrogen peroxide, the reaction product of NADH-oxidase activity, in normal and ischemic dog myocardium. The NADH-oxidase reaction product was present in weak amounts in mitochondria from normoxic myocardium. In viable ischemic areas a high degree of activity was observed in the mitochondria. In infarcted tissue mitochondria contained few or no reaction product at all. The results support the hypothesis that hydrogen peroxide and oxygen radicals produced in the mitochondria by a high NADH-oxidase activity may contribute to the mitochondrial damage observed during ischemia when NADH is no longer oxidized by the respiratory chain and cellular defense mechanisms are impaired.

Animals↗
PubMed1986

Diffuse intravascular coagulation complicating thrombosis of a popliteal aneurysm: a case report.

Several reports have described the association between diffuse intravascular coagulation (DIC) and arterial aneurysmal disease. We report a patient with extensive arterial aneurysmal disease who developed transient severe DIC during thrombosis of a popliteal aneurysm; following surgical removal of the thrombosed aneurysm, he was found to have chronic subclinical DIC. We believe thrombosis should be added to the complications of aneurysms which can cause DIC, next to dissection and rupture. The chronic DIC occurring after removal of the thrombosed aneurysm was characterized by an abnormal prothrombin time (PTT), low fibrinogen levels and elevated fibrin split products (FDP's); this pattern may be characteristic of the DIC complicating arterial aneurysms.

Aged↗
PubMed1984

Beneficial effect of mioflazine in limiting myocardial infarct size in the anesthetized dog.

The effect of mioflazine (R 51 469) on infarct size was studied in anesthetized dogs subjected to 24 h of LAD (left anterior descending) coronary artery occlusion. The myocardium normally supplied by the occluded coronary artery (perfusion area, PA) was delineated by perfusion of the arterial bed distal to the occlusion with colorless fluid while the remainder of the heart was simultaneously perfused with an Evans blue solution. After sectioning the heart, infarct areas (IA) could be visualized by incubation of the slices in triphenyl-tetrazolium-chloride (TTC). Quantification of the areas was performed using a Quantimet 900 image analysis system. The animals either received mioflazine (2.5 mg X kg-1 orally) or a same volume of 20% polypropylene glycol, the solvent of mioflazine 2.5 h before the start of the surgical procedure. For perfusion areas greater than 20% of the left ventricle infarct size was significantly reduced in mioflazine pretreated animals compared with the control group, both expressed as per cent of the left ventricle (10.6 +/- 2.3 vs 19.2 +/- 1.5, p less than 0.005) and as per cent of the perfusion area (35.1 +/- 7 vs 64.4 +/- 5, p less than 0.005).

Anesthesia↗