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Biomedical subjects

A Jansen

Publications and source records attributed to A Jansen.

At least 91 records · Page 5Linked to original sources
PubMed1995

Quantitative standardised analysis of advanced laparoscopic surgical procedures.

To support the improvement of advanced laparoscopic surgical procedures, we designed a quantitative analysis method to monitor surgical activities. The emphasis lies on the time spent on these activities and on the instruments controlled by the hands of the surgeon. Our method uses combined video images originating from the laparoscope, an overview CCD camera placed in the operating theatre and, when available, a video colonoscope. After the operation is finished, the images are evaluated by means of a standardised analysis routine based on a spreadsheet program and a set of standard terms (thesaurus), to minimise subjectivity of the analysis. After calculations, the data are presented in tables and graphs, resulting in objective information for research on the operation. Seven advanced laparoscopic procedures, in this case colon resections, have been analysed, and it was demonstrated that the analysis method is capable of describing different laparoscopic procedures using the limited thesaurus. Possible areas of application of the method are the evaluation of time-consuming parts of the operation, of surgical tasks and measurement of the surgeon's learning curve. Other applications are the prediction and measurement of the impact of new instruments and techniques.

Colectomy↗
PubMed1994

Localization of inducible nitric oxide synthase in acute renal allograft rejection in the rat.

There is increasing evidence for a role for nitric oxide (NO) in the alloimmune response and induction of NO synthesis occurs during allograft rejection. The aim of this study was to investigate the source of NO synthesis in rejecting allografts. Localization of inducible nitric oxide synthase (iNOS) was studied by immunohistochemistry, in a rat model of acute renal allograft rejection, in unmodified Lewis recipients in which rejection is complete 7 days after transplantation of F1 hybrid Lewis-Brown Norway kidneys. High levels of iNOS expression were found in infiltrating mononuclear cells in glomeruli and interstitium of rejecting kidneys; there was no expression in parenchymal renal cells, or in control isografts of either rat strain. Expression of iNOS in the cortex was present from 4 to 6 days posttransplantation, and had declined by the 7th day, where expression was principally in the medulla. The pattern of iNOS staining was similar to ED1 staining, a marker for rat macrophages. These findings suggest that infiltrating macrophages in the graft reaction are a prominent source of NO; this iNOS expression supports a role for NO in the modulation of local allogeneic responses, and possibly as a mediator of cytotoxic graft damage.

Amino Acid Oxidoreductases↗
PubMed1994

[Are amylases in bakery products and flour potential food allergens?].

The enzyme alpha-amylase from the mould Aspergillus oryzae (Asp o II) routinely used for the production of bread, cakes and pastries has in recent years been identified as an inhalative allergen for occupational diseases (bakers' asthma). It is doubtful whether this amylase in the final product, i.e. after the baking procedure, can still be regarded as an allergen. To clarify this question, detailed case histories on 138 subjects were recorded (98 allergics, 20 patients suffering form chronic intestinal diseases, 20 healthy controls). The clinical examinations included prick skin test and IgE antibody determination using one of the customary enzyme preparations. EAST showed a few of these 138 bread consumers to be weakly sensitized to the enzyme. One of the subjects displayed a significant reaction to alpha-amylase heated to 200 degrees C. As expected, eleven bakers sensitized to alpha-amylase by inhaling it in the workplace (positive prick test, positive case history) predominantly exhibited specific IgE antibodies to the native enzyme. Apart from one weakly positive finding, heated alpha-amylase yielded negative results in this collective. Baking conditions vary widely, especially with regard to single components, temperature and duration. Thus, further investigations as to residual allergenicity or the feasible occurrence of new antigenic determinants during the production of bread, cake and pastries are required. 27% of bakers examined and 9% of atopics showed antibodies to a flour inherent enzyme, a beta-amylase. On the whole, the selected conditions hinted at a weakly sensitizing potential inherent in baking flour and in added amylase.

Allergens↗
PubMed1994

In vivo sensitivity of Plasmodium falciparum to chloroquine in rural areas of Côte d'Ivoire.

In vivo testing of Plasmodium falciparum sensitivity to chloroquine was carried out in four rural sites of differing socio-geographical environment in Côte d'Ivoire. Of a total of 1282 patients of all ages with fever or previous history of fever, 649 were slide positive, with 435 patients with a pure P. falciparum infection; 191 fulfilled all the criteria for inclusion in this study, and 113 completed it. Treatment failure rates ranged from 9.7% (Djébonoua) to 38.1% (Tiéviéssou), and were most often associated with higher degrees of resistance (RII = 54.2%; RIII = 37.5%). Blood chloroquine levels measured by ELISA test suggest that many people take chloroquine routinely; furthermore 37.5% of resistance cases occurred in subjects who had high blood chloroquine concentrations on day 0. Twenty-three out of 24 cases of resistance were found in children under 7 years of age. Nearly all children with persisting parasitaemia were afebrile on day 7, even those (7/8) with RIII resistance. Children aged < 7 years represent the the best sentinel group for monitoring P. falciparum sensitivity to chloroquine in Côte d'Ivoire.

Adolescent↗
PubMed1994

Induction of nitric oxide synthase in rat immune complex glomerulonephritis.

Nitric oxide (NO) is a biological mediator which is synthesized from L-arginine by a family of nitric oxide synthases (NOS). Previously we have shown that NO is synthesized ex vivo by glomeruli obtained from animals with acute immune complex glomerulonephritis. We have now sought evidence for the in vivo induction of NOS in glomeruli by immunohistochemistry using specific antisera raised against a peptide sequence of inducible mouse macrophage NOS and by in situ hybridization. The expression of the enzyme was studied in kidneys of rats with acute unilateral immune complex glomerulonephritis, induced by cationized IgG, by immunohistochemistry. Inducible NOS (iNOS) was present in glomeruli in nephritic (left) kidneys at the time of maximum macrophage infiltration, both within intraglomerular mononuclear cells and cells emigrating into Bowman's space. iNOS expressing cells were also present in interstitial infiltrates. There was no expression in normal rat kidneys or in glomeruli in the non-nephritic (right) kidneys of experimental rats. In situ hybridization confirmed the immunohistochemical localization. These results provide the first direct evidence for the presence and localization of inducible NOS in glomeruli and support a significant role for NO in the pathogenesis of immune complex glomerulonephritis.

Amino Acid Oxidoreductases↗
PubMed1994

Arginine metabolism in experimental glomerulonephritis: interaction between nitric oxide synthase and arginase.

L-Arginine is metabolized by two pathways: 1) by nitric oxide synthase (NOS) to nitric oxide (NO) and 2) by arginase forming urea and L-ornithine. Inflammatory responses may involve a balance between the pathways, as NO is cytotoxic and vasodilatory and L-ornithine is a promoter of cell proliferation and matrix synthesis. In experimental glomerulonephritis we have previously shown that NOS is activated in nephritic glomeruli. We have now examined both pathways of L-arginine metabolism to study competition for L-arginine, temporal variation, and the sources of NOS and arginase. Acute in situ glomerulonephritis was induced in rats, and glomeruli were studied at 1, 4, and 7 days. Both NOS and arginase activities were present. There was temporal variation: NOS activity was highest on day 1 and arginase activity on day 4; both declined by day 7. Competition between the pathways was demonstrated by increased urea synthesis in the presence of NG-monomethyl-L-arginine, an inhibitor of NOS. Measurement of NOS and arginase activities in macrophages isolated from nephritic glomeruli showed that these cells were a major source of glomerular NOS but not arginase activity. In contrast, high arginase activity but low NO production was identified in cultured rat glomerular mesangial cells. These studies show differential temporal variation in expression of NOS and arginase pathways of arginine metabolism in experimental glomerulonephritis. We have found two factors that may contribute to this: 1) competition for substrate L-arginine between the two pathways and 2) different cellular sources. We hypothesize that the balance between these pathways is a mechanism regulating injury, hemodynamics, and mesangial cell proliferation.

Amino Acid Oxidoreductases↗
PubMed1994

Immunohistochemical characterization of monocytes-macrophages and dendritic cells involved in the initiation of the insulitis and beta-cell destruction in NOD mice.

This immunohistochemical study describes the infiltration pattern of monocytes-macrophages and dendritic cells during the development of insulitis and diabetes in the NOD mouse. A panel of monoclonal antibodies (MoAbs) was used to analyze pancreases of nondiabetic (glucosuria negative) male and female NOD mice at 3, 7, 10, and 17 weeks of age. BALB/c female mice 17-weeks-old, diabetic NOD female mice 20- to 30-weeks-old, and nondiabetic NOD male mice 22-weeks-old were used as controls. Three MoAbs (viz., ER-MP23, MOMA1, and BM8) were special and appeared to identify macrophage/dendritic cell subsets that either had a characteristic infiltration pattern in the initial phases of the autoimmune reaction before T-cell infiltration or were typical for the later beta-cell destructive insulitis process. 1) Raised numbers of ER-MP23+ and MOMA-1+ dendritic cells/macrophages were characteristic for the initial phases of the NOD insulitis in 3-week-old mice. The cells were found in and near swollen para-insular vessels. In 7-week-old mice, these ER-MP23+ and MOMA-1+ cells had accumulated around the islets and were the first hematopoietic cells detectable at these spots. 2) From 7 weeks of age onward, BM8+ macrophages could be found in the para- and peri-insulitis processes. However, only in females were these BM8+ macrophages found to infiltrate into the islets. In lymphoid tissues, ER-MP23 predominantly reacts with macrophages/dendritic cells present in the subcapsular and interfollicular sinuses of lymph nodes and the T-cell zones of these lymph nodes. ER-MP23 also reacts with tissue macrophages/dendritic cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Relaxation of human bronchial smooth muscle by S-nitrosothiols in vitro.

S-Nitrosothiols (RS-NO) relax tracheal smooth muscle from a variety of animal species, and may have physiological relevance. We therefore studied their effects on human bronchial smooth muscle. S-Nitroso adducts of glutathione, cysteine, N-acetylcysteine and bovine serum albumin relaxed tissues contracted with methacholine with mean IC50 +/- S.E.M. of 3.3 (+/- 14), 22 (+/- 45), 25 (+/- 22) and 36 (+/- 7.1) microM, respectively; they were more potent as inhibitory agonists than the corresponding reduced thiol, NaNO2, or theophylline, but less potent than isoproterenol (P < .001). Despite large differences in their molecular weights and dissociation kinetics, the IC50 of these RS-NO did not differ significantly from one another, from nitric oxide (NO.) or from sodium nitroprusside. Consistent with the role of cyclic GMP (cGMP) in mediating relaxation responses, S-nitroso-N-acetyl cysteine (S-NO-AC) (100 microM) increased tissue cGMP levels 4-fold, and 8-bromo-cGMP caused modest tissue relaxation which was potentiated by the phosphodiesterase inhibitor, dipyridamole (1 microM). However, the guanylyl cyclase inhibitors, methylene blue (100 microM) and LY 83583 (50 microM), failed to modify the relaxation response to S-NO-AC (sodium nitroprusside and NO.), while altering the accumulation of cGMP. Further, hemoglobin (100 microM) failed to inhibit relaxation by S-NO-AC.(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchi↗
PubMed1994

Laparoscopic-assisted colon resection. Evolution from an experimental technique to a standardized surgical procedure.

Between October 1991 and November 1992, 51 patients in the mean age 63.2 years (range 19 to 91 years) underwent laparoscopic colon resection. Indications for surgery were colon carcinoma (31), adenomatous polyps (8), diverticulitis (10) and Crohn's disease (2). In right-sided lesions an extracorporeal anastomosis and in left-sided lesions an intracorporeal anastomosis was performed using the double stapling technique. The mortality rate was 1.9% and the morbidity rate 20.5% in the laparoscopic-treated group. The conversion rate was 13.7%. Except for one anastomotic leakage in a converted patient, no anastomotic problems were encountered. The percentage of infectious complications was 11.7%. Three reinterventions were necessary for treatment of two deep subfascial abscesses and one case of localized peritonitis, caused by a small small bowel injury. The mean hospital stay was 9.1 days (range 4-29 days). In the last 13 consecutive patients, except for a urinary infection, no further post-operative morbidity was encountered. Laparoscopic-assisted colon resection has evolved in to a standardized surgical technique. Initial learning problems are solved by good patient selection, better operative logistics and awareness of the dangers and pitfalls of laparoscopic surgery.

Adult↗
PubMed1994

Two-site enzyme immunoassay of CD4 and CD8 molecules on the surface of T lymphocytes from healthy subjects and HIV-1-infected patients.

A highly sensitive two-site enzyme immunoassay (Capcellia) was developed to determine the concentration of CD4 and CD8 molecules expressed on the surface of human T lymphocytes. This assay, performed in one step (20 min), involves the specific immunocapture of T lymphocytes and reaction of the CD4 or CD8 molecules with an enzyme-labeled monoclonal antibody (mAb). The results were expressed as molar concentrations of the T-cell markers on the basis of results obtained with calibrated CD4 and CD8 standards. The assay was sensitive enough to detect 0.4 pmol/L CD4 or 0.8 pmol/L CD8, which corresponded to approximately 20 x 10(6) CD4+ or CD8+ T cells per liter of blood. Mean concentrations in healthy adults were 17.2 pmol/L for CD4 and 22.1 pmol/L for CD8. The CD4 concentration was < 8 pmol/L in 50% of HIV-1-infected patients and in 95% of AIDS patients. Given the epitopic specificity of the mAb to CD4 we used, these values correspond to the concentration of CD4 molecules free of envelope glycoprotein (gp)120.

AIDS-Related Complex↗
PubMed1993

An immunohistochemical study on organized lymphoid cell infiltrates in fetal and neonatal pancreases. A comparison with similar infiltrates found in the pancreas of a diabetic infant.

Lymphoid cell infiltrates were analyzed using immunohistochemical techniques on 5 normal fetal and 6 normal neonatal pancreases. Data were compared to data obtained analyzing the lymphoid cell infiltrates in the pancreas of an 8 months old diabetic infant. In the normal fetal and neonatal pancreases islets were intact and not infiltrated. In the diabetic infant beta-cells had vanished in almost all islets, the remaining islets showed a minor infiltration with primarily T-cells, a few B-cells, and some classical macrophages. It appeared that a widespread infiltration of the exocrine pancreas with single dendritic-like cells, and T-cells, and little clusters of these cells were normal features of fetal and neonatal pancreases. In the diabetic case these infiltrative patterns were more pronounced. Larger accumulations of such lymphoid cells could also be detected in the normal fetal and neonatal pancreases and these consisted mainly of T-cell zones, sometimes containing HEV's, with intermingled interdigitating dendritic cells and a few macrophages. This architecture is reminiscent of peripheral lymphoid tissue, such as bronchus-or gut-associated lymphoid tissue. The function of this fetal/neonatal intrapancreatic lymphoid tissue (which disappears in later life) is unknown. Various possibilities are suggested such as a yet unknown ubiquitous fetal/neonatal microbial infection, tolerance induction towards islet cell antigens, an endocrine regulatory function of infiltrated lymphoid cells, and a normal ontogenetic process.

Age Factors↗
PubMed1992

Golgi vacuolization and immunotoxin enhancement by monensin and perhexiline depend on a serum protein. Implications for intracellular trafficking.

Vacuole formation around the Golgi and immunotoxin enhancement induced by low doses of the ionophore monensin were inhibited by 50% human plasma (final concentration), whereas the lysosomal pH increase remained unaffected. Immunotoxin enhancement by the Ca2+ antagonist perhexiline was also inhibited by plasma. The inhibiting factor was present in different species and highly concentration-dependent. After purification on DEAE- and CM-Sepharose it showed a heterogeneous distribution between 45 and 50 kDa, in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, an extreme isoelectric point near 3.5, and binding to wheat germ agglutinin-Sepharose. Maximum inhibition was found in the lower molecular mass fraction of 45 kDa. The 50-kDa fraction, although showing immunological identity reactions, remained almost inactive. The simultaneous inhibition of morphological alterations and the enhancement of immunotoxin activity by the highly enriched protein provides a first direct link between both events. Apart from a role of this serum glycoprotein on in vivo inhibition of immunotoxin enhancement, its ability to maintain normal intracellular trafficking in the presence of blocking agents, such as monensin and perhexiline, suggests a more fundamental role in the regulation of these mechanisms.

Biological Transport↗
PubMed1992

German multicentre study on the in vitro susceptibility of Bacteroides species. The German Bacteroides Study Group.

In 1990 the first German multicentre study on the in vitro susceptibility of Bacteroides species was completed. Employing a commercially prepared microbroth dilution assay, nine participating institutions evaluated approximately 100 consecutive isolates of Bacteroides species from relevant clinical specimens. A total of 911 strains (449 Bacteroides fragilis, 201 Bacteroides thetaiotaomicron, 79 Bacteroides ovatus, 78 Bacteroides vulgatus, 77 Bacteroides distasonis, 25 Bacteroides uniformis, 2 others) were tested. Most of the isolates came from surgical patients (72%); other sources included gynaecological patients (9%) and medical patients (5%). Seventy-eight percent of the anaerobes were found in mixed culture together with at least one aerobic organism (Escherichia coli 36%, streptococci 15%, or enterococci 13%), while in 22% of the cases, the anaerobes were the only bacteria grown from the specimens. The results showed that many of the strains were potent beta-lactamase producers (as judged by resistance to amoxicillin). However, all but one of the isolates demonstrated susceptibility in vitro when clavulanic acid was added to amoxicillin or ticarcillin. At the same time, 13% of the organisms were resistant to mezlocillin, 5% to cefoxitin and 4% to clindamycin. Three strains were reported resistant to imipenem and one strain to metronidazole.

Anti-Bacterial Agents↗
PubMed1992

Cue-exposure vs self-control in the treatment of binge eating: a pilot study.

From a recent theory on the learned nature of craving responses and binge eating, it follows that craving will extinguish when the CS-US bond is broken by prolonged exposure to the cues predicting excessive food intake with response prevention. The present authors treated six obese bulimics with cue exposure and response prevention. Six other patients learned to avoid or escape the binge-related cues with the aid of self control techniques. Although both treatments appeared to be effective in reducing the binge frequency, a most remarkable finding of the present study is that all patients treated by cue exposure were abstinent, directly after treatment and during the 1 yr follow-up. In contrast to the 100% binge-free subjects treated by cue exposure, self control techniques and relapse prevention led to abstinence in merely 33% of the subjects.

Adult↗
PubMed1992

No counterregulation after breaking the external restraint of children.

At the present, it is unknown how restraint and binge eating/counterregulation are exactly related. Earlier studies on this relationship suffer from two main shortcomings: the studies are all correlational in nature or could not rule out the contribution of confounding variables such as weight loss. The present study investigated whether a break of restraint is a sufficient condition for the occurrence of counterregulation by studying a restrained sample which is not liable to dieting practices and weight loss. The externally imposed restraint on children with regard to eating sweets was broken. However, after breaking their external restraint the children did not counterregulate. It is discussed whether restraint of food intake is really as important for binge eating as it is claimed to be or whether it is merely a consequence or an epiphenomenon of binge eating.

Bulimia↗
PubMed1992

Salivation discordant with hunger.

In the present study, the authors tested whether an increase in salivation is associated with an increase in subjectively experienced hunger. After conditioning, subjects showed a significant increase in salivation flow. Hunger levels, however, were significantly decreased after conditioning. No correlation was found between salivation flow and hunger levels. It is argued that salivation responses and subjectively experienced hunger are loosely coupled systems. Salivation flow reflects the learning history of a subject which may sometimes be paralleled by a biological state which is called hunger, whereas, at other times, hunger may be absent. The authors conclude that conditioning of preparatory responses such as salivation depends on the probability relationship between exposure to cues (CSs) and food intake (US), as well as the intensity of the US.

Adult↗