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Biomedical subjects

J Buchholz

Publications and source records attributed to J Buchholz.

52 records · Page 3Linked to original sources
PubMed1989

[Intra-arterial infusion therapy of progressive diabetic foot gangrene with prostaglandin E1 amd cefotaxime].

15 patients with severe diabetic gangrene were treated with a combined intra-arterial PGE1/Cefotaxime infusion therapy. There was no indication for vascular reconstructive surgery. The average treatment took 24.7 days. 11 of the 15 patients were responsive to the therapy. Nevertheless 5 of these 11 patients had to be amputated below-knee in the further course of treatment. In 6 cases we succeeded in preserving the affected extremity in a state of acceptable use. One patient died during the study. No complications due to the therapy were seen. Considering that all patients were near to amputation when entering the study the result to have saved the extremities in 40% of the cases must be regarded as a success.

Alprostadil↗
PubMed1988

Electrotransfer of proteins after isoelectric focusing (with or without urea) on fabric-reinforced, immobilized pH gradient gels.

In the present article a procedure is described which combines the horizontal isoelectric focusing (IEF) of proteins on fabric-reinforced polyacrylamide gels with the subsequent electrophoretic transfer of the proteins to nitrocellulose or Immobilon. The application of a carrier material that is permeable for current and molecules and that serves as a physical support of the IEF gel is one of the central prerequisites for the method to work. Moreover, it is important to fix the pH gradient topographically by the use of Immobilines mainly in order to avoid distortion of the protein pattern during the electrotransfer (Western blot). The Western blot can be performed either in the submerse or in the so-called "semi-dry" blotting system. Our procedure is compatible with IEF protocols employing buffer systems with or without urea. The efficacy of our method is demonstrated by the IEF and Western blotting of several known marker proteins.

Acrylic Resins↗
PubMed1988

Difference in cell surface 5'-nucleotidase activity, protein iodination and membrane properties between mouse lymphoma and rat adenocarcinoma cell variants with low and high-metastatic potential.

1. Distinct differences were found for the specific, concanavalin A-inhibitable 5'-nucleotidase activity, exhibiting 2-7 times higher values in the low-metastasizing cell variants. 2. Iodination of the cell surface proteins revealed a more heterogeneous labelling pattern of the high-malignant cell lines in the molecular weight range between 14 and about 35 kDa. 3. The low-malignant cell lines exhibited a significantly higher surface charge as deduced from their higher sialic acid content compared to the high-malignant variants. 4. They also showed a greater membrane lipid fluidity as determined both by the cholesterol to phospholipid ratio and by fluorescence depolarization measurements.

5'-Nucleotidase↗
PubMed1988

[Primary malignant tumors of the small intestine--symptoms, diagnosis and therapy].

26 patients with a primary malignant tumor of the small intestine could be found in the cases in the surgical department of the Marienhospital Herne, University of Bochum, from 1978 to 1987. By the anamnesis and findings on admission various symptoms and clinical results only a few cases advising symptoms for a malignant tumor of the small intestine were found. Often the diagnosis only could be found by an emergency operation. An amelioration of the bad prognosis will be possible with shortening the long latency between the first uncharacteristic symptoms and the right diagnosis. After going through the endoscopy and radiology with strong anamnesis and findings, the explorative laparotomy must be done as an compulsory step.

Adenocarcinoma↗
PubMed1987

Glucose effect on drug action, metabolism, and pharmacokinetic parameters in mice.

The glucose effect on hepatic drug metabolism (decreased) of barbiturates was maximum after 2 days of increased glucose intake as indicated by increased barbiturate sleep time in mice. However, this effect was not observed after 5 days of glucose treatment, and barbiturate sleep time was similar to the control after 6 days of treatment. Serum glucose and liver glycogen were, in general, not significantly different from control, even after chronic glucose intake, indicating that neither hypoglycemia nor alteration of liver glycogen levels were required for the glucose effect on drug action. However, in contrast to the decreased metabolism of barbiturate, there was increased metabolism of glucose in the glucose-treated animals. Brain levels of barbiturate in 48 hours glucose-treated mice were higher and declined at approximately half the rate of controls (Ke(G) 0.009 vs Ke(C) 0.015). A similar trend in barbiturate blood concentration indicated decreased metabolism of the barbiturate and/or decreased clearance of drug and metabolites. The glucose treatment altered the pentobarbital dose response curve, but there appeared to be no alteration of the sensitivity to insulin; exogenase insulin still produced significant hypoglycemia and prolonged barbiturate S.T. after 7 days of glucose treatment. Other factors may be involved in the glucose effect; increased permeability of the brain to barbiturate, decreased permeability to outflow so that brain concentrations remain higher for a long period of time.

Animals↗
PubMed1986

[Clinical significance of histologic mastopathy diagnosis using quantitative procedures].

Examinations were applied to 101 patients with simple fibrocystic mastopathy (15 cases), proliferative mastopathy (52 cases), invasive ductal carcinoma in concomitance with mastopathy (21 cases), and normal mammary glands (13 probands) in a prospective clinico-morphological pilot study. The use of Robotron A 6471/AMBA-R, a system for automated microscopic image analysis, together with improved methods, has opened up new possibilities for early detection of precancerous changes of the mammary gland. Significant differences were identified between the two clinically relevant groups, II and III, of proliferative mastopathy by quantitative analysis of ductal epithelial proliferations through reproducible measuring data were obtained together with highly distinctive karyometric and histometric parameters. Multiparametrical analysis also provided suggestions to the effect that cases of proliferative mastopathy III, probably, break down into two groups with presumedly differentiated carcinoma risks. Hence, it may well be possible that the biological importance of atypical ductal epithelial proliferations differs from case to case.

Adult↗
PubMed1977

[Basic data in the application of a new intensity distribution in laser treatment of the upper digestive tract].

A new pattern of intensity distribution of laser beam, in the shape of a "topfkuchen" was found to be satisfactory in avoiding perforation when applied to the gastrointestinal tract. Basic data of the optical and thermophysical properties of the different layers in the stomach of pigs were obtained. Using our distribution pattern of intensity we could see a uniform, superficial zone of coagulation. There were no perforations even after the intact mucosa of the stomach was irradiated by 175 Watts for 2 seconds.

Animals↗
PubMedDate not supplied

Age-related changes in the sensitivity of sympathetic nerves to altered extracellular calcium in tail arteries of F-344 rats.

There is a significant age-related increase in stimulation evoked norepinephrine release from adrenergic nerves in tail arteries of F-344 rats, that is not accounted for by a change in function of prejunctional alpha 2-adrenergic receptors. To further explore the mechanism of this age-related change in transmitter release, we investigated the effect of altered extracellular calcium. With short stimulation trains the effects of altered extracellular calcium were significantly greater in 20-month-old tail arteries compared to 6 months. At the highest calcium concentration (7.5 mM) when alpha 2-adrenergic receptors were active or blocked, there was a significant decline in fractional norepinephrine release only in arteries of 20-month-old animals. With long stimulation trains the effects of altered extracellular calcium were not as pronounced as with short trains, but the effect of calcium was still significantly greater in 20 month old tail arteries. With alpha 2-adrenergic receptors blocked 6 month tail arteries were insensitive to altered calcium while 20-month tail arteries remained sensitive. One explanation for these findings may be an age-related change in the efficiency of intracellular calcium buffering mechanisms leading to greater calcium transients in the nerves of older animals.

Aging↗
PubMedDate not supplied

Rat tail artery norepinephrine release: age and effect of mitochondrial blockade.

An age-related increase in stimulation-evoked fractional norepinephrine release has been demonstrated in tail artery of Fischer-344 rats from 6 to 20 months of age. Previous studies have ruled out alterations in function of uptake mechanisms, metabolism, or feedback via prejunctional alpha-2 adrenoceptors, suggesting that an age-related decline in calcium homeostasis may be responsible. To test this possibility, stimulation-evoked fractional norepinephrine release from perivascular adrenergic nerves of rat tail arteries in the presence of a blocker of mitochondrial calcium uptake, dinitrophenol (100 microM), was measured using HPLC with electrochemical detection. When the mitochondrial proton gradient was dissipated by dinitrophenol, tail arteries from 20-month-old animals showed a marked increase in stimulation-evoked norepinephrine release whereas arteries from 6-month-old animals were not affected. One hypothesis is that the inhibition of mitochondrial calcium uptake in the adrenergic nerves from older animals resulted in an elevated intracellular calcium level. In agreement with this idea, when extracellular calcium was raised from 1.6 to 5 mM, stimulation-evoked norepinephrine release was increased in the 6-month tail arteries in the presence of dinitrophenol. These data suggest that there may be a decline in calcium regulation in older nerves leading to increased norepinephrine release with advancing age.

Aging↗
PubMedDate not supplied

Advancing age alters intracellular calcium buffering in rat adrenergic nerves.

There is a marked increase with advancing age of stimulation-evoked neurotransmitter release from vascular adrenergic nerves in the rat, an effect correlated with increased levels of plasma norepinephrine. This increase in norepinephrine release could not be accounted for by an alteration in neuronal and extraneuronal uptake of norepinephrine or a decline in feedback inhibition of release by prejunctional alpha2-adrenergic receptors. Measurement of intracellular calcium in fura-2-labeled superior cervical ganglion cells revealed elevated K+-evoked calcium transients in old compared to young neurons. Blockade of mitochondrial calcium uptake with dinitrophenol resulted in increased calcium transients in old neurons only. Furthermore, following blockade of mitochondrial calcium uptake the rate of return of calcium to resting levels was reduced to a greater degree in old cells as compared to young cells. The effects of dinitrophenol in old cells were attenuated when extracellular calcium was reduced. These findings suggest that older cells are more dependent on mitochondrial calcium buffering, perhaps due to changes in ATP dependent calcium uptake. Increased calcium transients as a result of altered intracellular calcium buffering offer a reasonable explanation for our previous observation of increased stimulation evoked norepinephrine release.

Aging↗
PubMedDate not supplied

Implantation technique and complications of totally implanted arterial access systems for long-term therapy in patients with occlusive vascular disease.

Twenty-six totally implantable catheter systems for intra-arterial infusions were used in patients with peripheral arterial occlusive disease. A total of 606 short-term infusions were administered via the system. The patients were observed up to 22 months. There was an over-all rate of complications in 15.3%. The complications described were: one catheter occlusion, one dislocation, one case of local infection and one case of arterial thrombosis. The latter was successfully treated with local lysis therapy. The system is distinguished from conventional methods of arterial access by its long-term use and the low incidence of complications. The system was extremely well accepted by the patients.

Aged↗
PubMedDate not supplied

In vitro metabolism of the antimalarial agent primaquine by mouse liver enzymes and identification of a methemoglobin-forming metabolite.

From a mouse liver microsomal system, we have isolated and identified a methemoglobin-forming metabolite of primaquine (PQ). Evidence has been found for both O-dealkylation and hydroxylation of PQ to form a metabolite, 5,6-dihydroxy-8-(4-amino-1-methylbutylamino)quinoline, which is highly active in forming methemoglobin in both normal and glucose-6-phosphate dehydrogenase-deficient erythrocytes. It also actively decreases glutathione levels in glucose-6-phosphate dehydrogenase-deficient erythrocytes. The inhibitor SKF 525-A prevented metabolite formation while iproniazid and carbon monoxide did not inhibit metabolism completely but may have resulted in formation of a different unidentified metabolite. Mass spectrometry, HPLC, NMR, and other more indirect methods were used to help identify the metabolite. It was identified indirectly via a blue compound which results from extracting the actual metabolite from the incubation mixture with organic solvents under alkaline conditions in the presence of light. The blue compound was identified as a quinonimine in which the 8-amino side chain of PQ cyclizes to produce a third ring system.

Animals↗