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Biomedical subjects

M Koch

Publications and source records attributed to M Koch.

At least 343 records · Page 19Linked to original sources
PubMed1990

Changes of peritoneal membrane function during long-term CAPD.

Peritoneal equilibration tests (PETs) in patients on CAPD show wide variations. To find out whether these are correlated with time on CAPD, we investigated changes in PET in 97 tests in 86 patients. 46 PETs were performed with a 1.36% glucose solution and 40 PETs with a 3.86% glucose solution at different time intervals. Neither did the intra-individual comparison of 11 patients with 1.36% glucose solution following 1 year of treatment show any significant change nor the inter-individual comparison following a treatment time of 1 and 2 years. There was also no difference using a 3.86% glucose exchange, when the results at the beginning and after 1 year were compared. However, alterations in equilibration ratios were significant after 24 and 36 months of treatment for creatinine (36 months versus 0: p less than 0.005), glucose absorption (36 months versus 0: p less than 0.01) and UF (36 months versus 0: p less than 0.01). No correlation exists between these changes either with the number of peritonitis episodes or with the time of treatment. Though, no single factor could be identified, patients had an increase in peritoneal permeability especially after long-term treatment. Further investigations are necessary to evaluate the reasons for these changes.

Diabetic Nephropathies↗
PubMed1990

[Alkaloids and flavonoid from aerial parts of Hammada articulata ssp. scoparia].

Two alkaloids (N-methylisosalsoline and carnegine) had been previously described from the aerial parts of Hammada articulata ssp. scoparia. A thorough study of this plant material has now led to the isolation of eight minor alkaloids and one flavonoid. The alkaloids include four isoquinolines (isosalsoline, salsolidine, dehydrosalsolidine and isosalsolidine), one isoquinolone (N-methylcorydaldine), tryptamine, N-omega-methyltryptamine and one beta-carboline (tetrahydroharman). The flavonoid has been identified as isorhamnetin-3-O-beta-D-robinobioside. The structures have been elucidated on the basis of spectral data, mainly mass spectrometry (D-IC) and 1H NMR.

Algeria↗
PubMed1990

Hemodialysis-related induction of beta 2-microglobulin synthesis and release by mononuclear phagocytes.

We have investigated beta 2-microglobulin (beta 2M) synthesis and release by blood leukocytes and isolated mononuclear phagocytes. Since beta 2M was discovered to form amyloid fibrils in patients undergoing long term, chronic hemodialysis and monomeric beta 2M levels in plasma of these patients are highly elevated, and since hemodialysis-related factors that increase beta 2M production are unknown, we evaluated beta 2M production by mononuclear phagocytes under a variety of conditions. We utilized a novel enzyme-lined immunoabsorbant assay to quantitate beta 2M release. Adherence of macrophages onto polystyrene or Cuprophan membranes does not induce beta 2M synthesis or release. In contrast, interaction of macrophages with lipopolysaccharide, gamma-interferon, tumor necrosis factor, or interleukin 1 induces synthesis or release. In contrast, interaction of macrophages with lipopolysaccharide, gamma-interferon, tumor necrosis factor, or interleukin 1 induces synthesis and release of beta 2M, indicating that beta 2M synthesis is increased during macrophage activation. Exposing leukocytes or macrophages to changes in osmotic or oncotic pressure induces a rapid release of beta 2M and interleukin 1 into the cellular medium. These results suggest that during hemodialysis, beta 2M production is more likely to result from endotoxin contamination, or osmotic and oncotic changes, rather than direct interaction of mononuclear phagocytes with cellulosic membranes.

Cell Adhesion↗
PubMed1990

[Two-dimensional echocardiography in the diagnosis of intracardiac metastases].

The authors describe the echocardiographic features of 19 cases of intracardiac metastatic tumours diagnosed over a 5-year period. The cardiac appearances were very varied: pericardial effusion alone or associated with an intrapericardial tumour (9 cases), myocardial infiltration (9 cases), immobile or mobile intracavitary tumour sometimes simulating a myxoma (15 cases). In 18 out of the 19 cases, the tumour mass was hyperechogenic which made it easy to diagnose. However, in one case of right atrial tumour, the mass was hypoechogenic and the diagnosis could only be made by contrast echocardiography. This study illustrates the important role that two-dimensional echocardiography plays in the non-invasive diagnosis of intracardiac metastatic tumours but physicians should be aware of the potential pitfalls and limitations of the technique.

Aged↗
PubMed1990

[Treatment of cardiac insufficiency in ischemic heart disease].

Over 30 per cent of coronary patients die of cardiac failure excluding the acute phase of myocardial infarction. With the exception of preexisting hypertension, there is no compensatory hypertrophy in ischemic heart disease. However, hypertrophy is a costly adaptation in terms of myocardial oxygen demand and, therefore, coronary flow. Fibrous zones are unresponsive to inotropic drugs and so the treatment of cardiac failure due to ischemic heart disease consists in limiting or preventing episodes of ischemia. Each mechanism of ischemia has an appropriate treatment: the preload is reduced by trinitrin and its derivatives and by molsidomine; the after-load by calcium antagonists and angiotensin converting enzyme inhibitors; tachycardia and hypercontractile states by betablockers. The risk of arrhythmia, aggravated by many inotropic therapies, constitutes the major danger to ischemic heart failure; amiodarone, betablockers and preventive nitrate therapy are the most effective and least dangerous antiarrhythmics. Revascularisation is effective for permanently ischemic segments or for ischemia on effort but does not improve large plaques of fibrosis which sometimes require surgical ablation or plastic procedures. But these measures are incomplete if all aspects of the disease are not taken in consideration: loss of excessive body weight, exercise rehabilitation by modern techniques, limitation of bed rest at the ultimate stage of the disease allowing patients with ischemic cardiac failure a better quality of life without aggravating the prognosis.

Arrhythmias, Cardiac↗
PubMed1990

[Differential diagnosis by MRT of cavernous hemangiomas and malignant tumors of the liver--advantages of the multi-echo technic].

With a retrospective analysis of images from 39 patients with histologically proven liver tumours we tried to determine the best MRT-parameter for detection of cavernous hemangioma (n = 19) and its differentiation from malignoma (metastases n = 17, HCC n = 5). The best differentiation was achieved with the contrast-to-noise ratio between lesion and liver in multi-echo-images with TR/TE = 2,000/210 ms and a definite limit with an accuracy of 84% for hemangioma and 91% for malignoma. The respective intensity ratios (lesion/liver) were 95% and 77%. T2-relation times and the T1- and T2-ratios were also calculated. In contrary to the literature we think that these parameters are not sufficiently discriminating.

Adult↗
PubMed1989

Methylglucamine orotate, a memory-improving drug, prolongs hippocampal long-term potentiation.

We showed earlier that the memory-improving substance, methylglucamine orotate, a precursor of pyrimidine nucleotide synthesis, improved memory retention and enhanced the postconditioning potentiation of field potentials in a special learning task. Since long-term potentiation (LTP) is frequently regarded as a mechanism of memory formation, we decided to test whether it can be influenced in a similar manner. The present study shows that the same dose of methylglucamine orotate (225 micrograms i.c.v.) prolongs LTP but has only a slight effect on the field potential recorded in the dentate gyrus. In controls, LTP of the population spike returned to 154% of the control value 24 h after tetanization and to 126% after 48 h. However, in drug treated animals LTP of the population spike remained at 246 and 216% of the control, respectively. The results support the assumption that LTP is at least a component of memory formation.

Animals↗
PubMed1989

Radiation dose and breast cancer risk in patients treated for cancer of the cervix.

The relationship between breast cancer and radiation treatment for cervical cancer was evaluated in an international study of 953 women who subsequently developed breast cancer and 1,806 matched controls. Radiation doses to the breast (average 0.31 Gy) and ovaries (average 32 Gy) were reconstructed for exposed subjects on the basis of their original radiotherapy records. Overall, 88% of the breast cancer cases and 89% of the controls received radiation treatment [relative risk (RR) = 0.88; 95% confidence interval (CI) = 0.7-1.2]. Among women with intact ovaries (561 cases, 1,037 controls), radiotherapy was linked to a significant 35% reduction in breast cancer risk, attributable in all likelihood to the cessation of ovarian function. Ovarian doses of 6 Gy were sufficient to reduce breast cancer risk but larger doses did not reduce risk further. This saturation-type response is probably due to the killing of a critical number of ovarian cells. Cervical cancer patients without ovaries (145 cases, 284 controls) were analyzed separately because such women are at especially low natural risk for breast cancer development. In theory, any effect of low-dose breast exposure, received incidentally during treatment for cervical cancer, should be more readily detectable. Among women without ovaries, there was a slight increase in breast cancer risk (RR = 1.07; 95% CI = 0.6-2.0), and a suggestion of a dose response with the RR being 1.0, 0.7, 1.5 and 3.1 for breast doses of 0, 0.01-0.24, 0.25-0.49 and 0.50+ Gy, respectively. However, this trend of increasing RR was not statistically significant. If low-dose radiation increases the risk of breast cancer among women over age 40 years, it appears that the risk is much lower than would be predicted from studies of younger women exposed to higher doses.

Adult↗
PubMed1989

Immunocytochemical localization and quantitation of estrogen-binding cells in the male and female (virgin, pregnant, lactating) mouse brain.

Estrogen-binding cells in the brains of male, virgin, pregnant, and lactating female mice were localized and quantified using an immunocytochemical technique. Nuclear estrogen-receptors were detected in cells of the midbrain periventricular gray, the cortical and medial amygdaloid nucleus, the arcuate nucleus and ventromedial nucleus of the hypothalamus, the anterior hypothalamic area and the preoptic area in animals of all 4 experimental groups. In virgin females, immunostaining was also seen in the hippocampus, the entorhinal and piriform cortex and in the septal nuclei. In pregnant females the anterior amygdaloid area and the bed nucleus of the stria terminalis were labelled additionally. After the first 5 days of lactation, estrogen-binding cells could no longer be detected in the hippocampus, entorhinal and piriform cortex and anterior amygdaloid area. These apparent qualitative differences in the pattern of estrogen-receptor immunostaining among the experimental groups are further accentuated by significant quantitative differences in the absolute numbers and relative densities of labelled cells in a given nucleus. Pregnant females have the highest numbers of estrogen-binding cells in many nuclei, whereas lactating females have the highest densities of labelled cells. These differences suggest a dynamic regulation of the number and distribution of estrogen-target cells in the respective brain areas initiated by, or as a result of hormonal states of the animals. Functional implications are discussed.

Animals↗
PubMed1989

The influence of parity and exogenous female hormones on the risk of colorectal cancer.

Evidence that female sex hormones may play a role in the subsequent development of colorectal cancer has accumulated from time trends in colorectal cancer rates and from epidemiologic studies. Using data available from the Cross Cancer Institute Northern Alberta Cancer Program, the relationship of parity, exogenous hormones and colorectal cancer was evaluated. Five hundred and twenty-eight colon cancer and 192 rectal cancer cases were identified and 349 nonendocrine cancers were selected as controls. All subjects were diagnosed and interviewed between 1969 and 1973. Protective associations between previous pregnancies and colorectal cancer were found in women over age 50 at diagnosis (OR = 0.5, 95% CI = 0.3-0.9) and in women who never used exogenous hormones (OR = 0.3, 95% CI = 0.2-0.7). Results from this study provide additional support for earlier suggestions that parity may have a protective effect against the development of colorectal cancer, similar to the effects reported in the case of breast, endometrial and ovarian tumors.

Adult↗
PubMed1989

Is quantitative assessment of insulin-antibodies and autoantibodies feasible?

Nine selected sera were studied using radioimmunoassay and enzyme linked immunosorbent assay; eight contained insulin antibodies and were from Type 1 (insulin-dependent) diabetic patients, one of whom had antibody-mediated insulin resistance, and one contained insulin-autoantibodies and was from an asymptomatic blood donor. Sera were assayed in serial dilution to assess their suitability for use as reference standards. Dilution curves were non-parallel in radioimmunoassay but were parallel in immunosorbent assay. In all sera, insulin antibodies were readily detected in both assays whereas the low avidity insulin autoantibodies were only detected by immunosorbent assay and not at all by radioimmunoassay, suggesting that the assays respond differently to antibodies of different avidity. Avidity was estimated in liquid phase from the dissociation rate of preformed complexes of antibody and 125-iodinated insulin. When high avidity antibodies are used as a reference in radioimmunoassay, lower avidity antibodies are underestimated and vice versa. In contrast, in immunosorbent assay, any serum could be used as a reference regardless of avidity; furthermore competition experiments comparing the highest avidity insulin antibodies, from the insulin-resistant patient, with the insulin autoantibodies from the asymptomatic blood donor yielded near-superimposable curves. We conclude that radioimmunoassay is selective for high avidity antibodies whereas enzyme linked immunosorbent assay is not; computer modelling of the two assays supports this conclusion. In practice immunosorbent assay can be standardized using a reference serum, whereas experimental findings and mathematical considerations preclude the use of a standard serum in radioimmunoassay.

Animals↗
PubMed1989

Myotonia congenita (Thomsen's disease) excluded from the region of the myotonic dystrophy locus on chromosome 19.

Linkage analysis has been carried out in six German families with autosomal dominantly inherited myotonia congenita (Thomsen's disease) using five chromosome 19 markers known to be linked to the gene for myotonic dystrophy (DM). Two of the markers, APOC1 and APOC2, are tightly linked to DM. Close linkage between these markers and myotonia congenita (MC) has been excluded to a distance of 9 cM (z = -2.158). These data support the clinical suggestion that MC and DM are non-allelic disorders.

Chromosomes, Human, Pair 19↗
PubMed1989

Estradiol and parental experience, but not prolactin are necessary for ultrasound recognition and pup-retrieving in the mouse.

The effects of estradiol, prolactin and experience with pups on pup-retrieving and on the recognition of ultrasonic distress calls of the young by adult ovariectomized female mice were studied. Treatment with estradiol benzoate or experience with pups (for 5 days) induced pup-retrieving in 40% and 60% of the animals, respectively, as compared to 0% in inexperienced ovariectomized females. However, if pup-experience was achieved in the presence of estradiol, retrieving was shown by 90.5% of the animals. In addition, in this case models of the ultrasonic distress calls of the pups were significantly preferred ("recognized") in a discrimination task by the females. These females also showed a sharp increase in serum prolactin concentrations. Depleting prolactin from the blood by cysteamine, however, neither reduced the retrieving score nor disturbed ultrasound recognition. Thus prolactin is dispensable for maintaining maternal pup-retrieving and ultrasound recognition. The process of achieving pup-experience is enhanced by the presence of estradiol. Possible actions of estradiol in the brain are discussed.

Animals↗
PubMed1989

Anti-ischemic effects of celiprolol in patients with exercise-induced angina pectoris.

The anti-ischemic properties of the new cardioselective beta-adrenoreceptor antagonist celiprolol were investigated in an open study of 12 men (mean age: 58 +/- 6.6 years) with exercise-induced angina pectoris. After all previous anti-anginal medication had been withdrawn for at least 5 half-lives, the patients received placebo, single doses of nitroglycerin buccal spray, sublingual nifedipine, celiprolol alone, and then in association with nitroglycerin and nifedipine. Exercise tests were performed on a bicycle ergometer, with continuous electrocardiographic monitoring. Significantly more work was completed after treatment with celiprolol than at baseline (5280 +/- 2500 versus 4005 +/- 1792 kpm; P less than 0.01). There were further improvements in work completed after the addition of nitroglycerin and nifedipine. Celiprolol reduced the mean resting heart rate from a baseline value of 77.1 beats/min to 69.2 beats/min (P less than 0.01). In contrast, nifedipine induced tachycardia (82.6 beats/min). At rest, all treatments significantly reduced systolic blood pressure, but only nifedipine significantly reduced diastolic blood pressure. At the completion of the exercise protocol, celiprolol reduced the maximal systolic and diastolic blood pressure (P less than 0.05) with further decreases after the addition of nifedipine. The double product was significantly decreased by celiprolol compared with control, nitroglycerin and nifedipine. There was a further improvement of the double product after the addition of nitroglycerin to celiprolol, but the further increase after addition of nifedipine was not significant. In conclusion, it is clear that celiprolol, both alone and in combination with nitroglycerin or nifedipine, can significantly increase the work capacity of patients with exercise-induced angina pectoris and significantly reduce myocardial oxygen consumption.

Adrenergic beta-Antagonists↗
PubMed1989

[Surgical treatment of renovascular hypertension in children].

The main reason for renovascular hypertension in children is ideopathic fibrous and fibromuscular displasia. The pathogenetic classification of the disease was worked out in 1971 by Harrison and McCormac. Of all cases of hypertension in children between 5 and 20% are of renovascular origin. The illness demands an absolute necessity for treatment. The concept of management of renovascular hypertension includes the conservative treatment as well as angioplasty and especially the surgical reconstruction of the arteries. Nephrectomy should be considered as the treatment of last resort. For the surgical reconstruction of arteries a variety of techniques are available. Aortorenal bypasses using autologous arterial or venous grafts are expecially suitable in surgical treatment of renovascular hypertension in children. Results given in literature of the management of 334 children with renovascular hypertension and 8 own cases were evaluated by us according to the criteria of the National Heart, Lung and Blood Institute. In the majority of surgical treated children a substantial improvement in the state of health, or cure, could be achieved.

Adolescent↗