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Biomedical subjects

B Mann

Publications and source records attributed to B Mann.

At least 19 recordsLinked to original sources
PubMed1995

Autocrine transforming growth factor alpha is dispensible for v-rasHa-induced epidermal neoplasia: potential involvement of alternate epidermal growth factor receptor ligands.

Autocrine epidermal growth factor receptor activation by transforming growth factor alpha (TGF alpha) has been implicated in growth stimulation during epithelial neoplasia. Using keratinocytes isolated from mice with genetic defects in TGF alpha expression, we tested whether TGF alpha is required for transformation by the v-rasHa oncogene. Introduction of v-rasHa into primary epidermal cultures using a retroviral vector stimulated growth of both control (TGF alpha +/+, BALB/c) and TGF alpha-deficient (TGF alpha -/-, wa-1) keratinocytes. Moreover, v-rasHa elicited characteristic changes in marker expression (keratin 1 was suppressed; keratin 8 was induced), previously shown to be associated with epidermal growth factor (EGF) receptor activation, in both TGF alpha +/+ and TGF alpha -/- keratinocytes. v-rasHa markedly increased secreted (> 10-fold) and cell-associated (2-3-fold) TGF alpha levels in keratinocytes from TGF alpha +/+ and BALB/c mice, but not TGF alpha -/- or wa-1 mice. Based on Northern blot analysis, v-rasHa induced striking up-regulation of transcripts encoding the additional EGF family members amphiregulin, heparin-binding EGF-like growth factor, and betacellulin in cultured keratinocytes from all four mouse strains. Interestingly, in addition to the normal 4.5-kilobase TGF alpha transcript, wa-1 keratinocytes expressed two additional TGF alpha transcripts, 4.7 and 5.2 kilobases long. All three transcripts were up-regulated in response to v-rasHa, as well as exogenous TGF alpha or keratinocyte growth factor treatment, and were also detected in RNA isolated from wa-1 brain and skin. In vivo, v-rasHa keratinocytes from control as well as TGF alpha-deficient mice produced squamous tumors when grafted onto nude mice, and these lesions expressed high levels of amphiregulin, heparin-binding EGF-like growth factor, and betacellulin mRNA, regardless of their TGF alpha status. These findings indicate that TGF alpha is not essential for epidermal neoplasia induced by the v-rasHa oncogene and suggest that another EGF family member(s) may contribute to autocrine growth stimulation of ras-transformed keratinocytes.

Animals↗
PubMed1995

Ovarian inhibin subunit gene expression: regulation by gonadotropins and estradiol.

Inhibin and FSH maintain a dynamic inverse relationship throughout the rat estrous cycle. In particular, inhibin alpha- and beta A-subunit messenger RNAs (mRNAs) have been shown to be maximally expressed immediately after the midcycle gonadotropin surge, when both circulating estradiol (E2) and inhibin are also elevated. The current study was designed to investigate the regulation of inhibin subunit gene expression and secretion in vivo by recombinant human FSH (rhFSH) and estradiol. Initially, we determined if physiological levels of rhFSH regulated ovarian inhibin subunit gene expression and secretion. Hypophysectomized (HYPOX) adult female rats received hCG (10 IU, sc) and were then treated for 24 h with either rhFSH (0.5-20 IU every 6 h, i.v.) or saline. Hypophysectomy reduced inhibin subunit mRNAs as well as serum inhibin and estradiol. Although 0.5 IU rhFSH was ineffective in increasing inhibin subunit mRNAs, all doses between 2.5-20 IU increased inhibin subunit gene expression and inhibin secretion. Inhibin alpha-, beta A-, and beta B-subunit mRNAs were increased to a similar degree (3- to 5-fold) by all rhFSH doses of 5 IU or more. Similarly, serum E2 and inhibin were increased 2- and 3-fold, respectively, above HYPOX values after all doses of rhFSH of 5 IU or more. To investigate the role of a pure FSH signal in a physiological dose on inhibin subunit gene expression, HYPOX rats were given either rhFSH (5 IU, i.v., every 6 h for 24 or 48 h), hCG (10 IU, sc), or their combination. Neither gonadotropin when given alone altered inhibin subunit gene expression or serum E2 concentrations. Inhibin secretion rose in response to rhFSH alone, but not to hCG. The combination of hCG and rhFSH resulted in increased inhibin subunit mRNAs (3- to 5-fold) as well as circulating E2 and inhibin concentrations. We next studied the effects of E2 replacement in HYPOX rats at both physiological (serum approximately equal to 40 pg/ml) and higher doses (serum approximately equal to 800 pg/ml, to mimic intraovarian concentrations) in the presence or absence of exogenous gonadotropins (for 24 and 48 h). Although not as effective as gonadotropins, both E2 regimens increased inhibin alpha to a similar degree (2-fold), whereas beta-subunit mRNAs were unchanged at 24 h. Serum inhibin concentrations were increased only 48 h after high dose E2 treatments. As the actions of E2 and gonadotropins on alpha-subunit mRNA were not additive, E2 appears to mediate gonadotropin regulation of alpha-subunit gene expression.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

A new automode switch algorithm for supraventricular tachycardias.

Patients with complete heart block on a spontaneous, or iatrogenic basis who also have recurrent supraventricular tachycardias, particularly atrial fibrillation and flutter, are often difficult to manage. Various techniques include: independently programmable maximum tracking and maximum sensor rates, limiting the maximum atrial tracking rate to the sensor response of the pacemaker, or automatically switching from DDDR to VVIR based upon the sensed atrial rate. This article will describe a mode switch algorithm that allows for an independently programmable atrial tachycardia detection rate (ATDR). This allows mode switching to occur only in response to the patient's pathological tachyarrhythmia, and not during normal upper rate response. The ATDR is based upon a filtered atrial rate, which will prevent an isolated premature beat from initiating the algorithm. In addition, the unit can be programmed to switch to either DDI, DDIR, VVI, or VVIR. Extensive event counters in the pulse generator allows the system to record and store the number of algorithm activations, the average atrial rate which triggered each mode switch, and the duration of the mode switch. These reports are accessible at each follow-up visit.

Algorithms↗
PubMed1994

[Postlaparoscopic pain syndrome. Results of a prospective, randomized study].

The so-called post-laparoscopic algesia is a specific impairment of about 63% of the patients who undergo laparoscopic surgical operations. This impairment takes the form of mild to moderate shoulder pain. Eliminating the causes of pain has a clear advantage over symptomatic treatment using analgetics, a fact worth a good consideration especially with the post-operative sojourn at the hospital becoming shorter and shorter. In a prospective controlled study, involving 42 patients subdivided into four groups namely, higher or lower insufflation pressures, chemically inert insufflation gas and control groups; the use of analgetics, lung function, operation duration, amount of insufflated gas, intraperitoneal pH-values and post-operative complications in the various subgroups were compared to each other with regard to post-operative pain perception. The results did not show any significant differences among the groups regarding the main parameters like pH-value or different insufflation pressures etc. These results led to the termination of the study based on the raised criteria since we anticipated the actual cause of the shoulder pain to be due to an unknown factor. By the evaluation of the individual data, it became apparent that, the pains increase with increasing gas consumption, a fact which led to assumption that the pains are caused by a physical effect such as the cooling of the peritoneum.

Acid-Base Equilibrium↗
PubMed1994

[Importance of proximal femoral fractures in elderly patients. Results of a prospective study of 61 patients].

In a prospective study we found good results concerning postoperative complications (21%), perioperative lethality (3.2%) and lethality during hospital stay (6.5%) after implantation of dynamic hip screws (DHS) in patients with per- and subtrochanteric fractures of the femur. The ability to walk, as well as housing and social care postoperatively and follow-up for at least six months after dismissal demonstrates the importance of these fractures for the elderly. One of three patients needs professional care, 21% at home, 13% in nursing homes. Six months after operation the lethality is nearly 20%, i.e. three times higher than in hospital. These are the essential data for all techniques of osteosynthesis used in patients with these fractures, which could only be documented in prospective studies.

Aged↗
PubMed1991

Evaluation of peroxyoxalate chemiluminescence postcolumn detection of fluphenazine in urine and blood plasma using high performance liquid chromatography.

Peroxyoxalate chemiluminescence may be used for sensitive postcolumn detection of phenothiazine analytes separated by high performance liquid chromatography with appropriate optimization of measurement conditions such as solvent, pH and oxalate ester. Detectability of fluorescent analytes by chemical excitation varies greatly, but analytes with low oxidation potentials are generally more readily detected at low levels, as demonstrated for phenothiazines, an important class of fluorescent drugs. Some improvement in detection limits is observed for fluphenazine when chemiluminescence detection is compared to conventional fluorescence detection. Because of the specificity of chemical excitation, fewer interferences from fluorescent impurities in a urine matrix are observed.

Chromatography, High Pressure Liquid↗
PubMed1991

[Pedicled small intestine segment for circular replacement of the extrahepatic bile duct in preserved papillary passage. An animal experiment study].

The effect of a small bowel segment as a extra-hepatic bile duct replacement was examined in 12 pigs followed-up for a period of 420 days. No complications, either during the operation or postoperatively, were observed in any of the animals. The laboratory parameters were within normal range over the entire observation period of 420 days. After 2, 6, and 12 months there was no anastomotic stenosis in the PTC. The intrahepatic biliary tract was not dilated. There was obvious peristalsis of the small bowel transplant towards the papilla of Vater. The autopsy showed that the grafts had healed without any sign of irritation. Histologically the structure of the graft remained undisturbed. There was a clear distinction between the mucosa of the bile duct and that of the small bowel, with no sign of a chronic infection. In the graft as well as in the vascular pedicle the nerve fibres were intact. Liver biopsy showed no pathological changes. In the light of these experiments, a small bowel segment presents a very promising alternative replacement of the extrahepatic biliary tract.

Ampulla of Vater↗
PubMed1991

[Animal experiment studies of pedicled small intestine transplantation as partial extrahepatic bile duct replacement].

A pedicle graft of the jejunum can in some cases enlarge a bile duct stricture. The enlargement of the patch and its consequences on the liver function are possible problems. In an animal experiment the following questions were sought. 1) Is a partial replacement of the bile duct with a pedicle graft of small bowel possible? 2) Is there an enlargement of the patch in every case and what are the consequences on the biliary tract and on liver function. The experiments were performed on 14 minipigs over a long-term observation period of 450 days. The red and white blood cell count, the GPT, GOT, GPT, bilirubin and alkaline phosphatase and copper were checked monthly. After 2, 6 and 12 months the intra- and extrahepatic biliary tract were visualized via a PTC. After 8 months an angiography of the pedicle graft was performed. 15 months later the animals were killed and the bile duct, the graft and the liver were histologically examined. 1) With a pedicle graft of small bowel a partial replacement of the extrahepatic bile duct is possible. 2) An enlargement of the patch is seen in every case. The enlargement is a consequence of tension at the pedicle. After 15 months no morphological changes were observed at the patch nor were there any irregularities in liver function.

Ampulla of Vater↗
PubMed1982

Observations on the phosphate status and intracellular pH of intact cells, protoplasts and chloroplasts from photosynthetic tissue using phosphorus-31 nuclear magnetic resonance.

Individual pools of intracellular inorganic phosphate (Pi) can be observed in the dark in intact cells, protoplasts and chloroplasts from photosynthetic tissue by using 31P nuclear magnetic resonance (n.m.r.). Estimates for the pH of vacuolar and extravacuolar compartments are reported although it is shown that intracellular pH is determined by the pH of the suspending medium. Mannose treatment of asparagus (Asparagus officinalis) cells and spinach (Spinacia oleracea) protoplasts results in the inhibition of photosynthesis. The mechanism of mannose phosphate sequestration of free Pi is supported by the 31P n.m.r. spectra of mannose-treated tissue. There is a fundamental difference in 31 P n.m.r. spectra of mannose-treated spinach protoplasts and asparagus cells, reflecting a difference in the availability of vacuolar Pi for cellular metabolism in these species. The 31P n.m.r. spectrum of intact spinach chloroplasts is reported.

Chloroplasts↗
PubMed1982

[Structure of supply--homes for the aged--as exemplified by a city (Nuremberg)].

Colloquies about the social-political instrument "old people's house" are not only matter of discussion for moral-theologicals, social-ethicals, gerontologists of different subjects, social-politicioner and practitioner of old people's work. Old people entering to an old people's house, are often involved with severe personal problems. Theoretical could the entrance be characterized as a break in biography.--Description and analyses of the structure of supply of the instrument "old people's house" as an example (here: city of Nuremberg) may help to clarify personal problems: aspects of the sociological point of view are "institutionalisation and comfort", of an economical point of view "prices for accommodation" and of an staff-economical point of view "the rate of care". The results shows among others, that there is a differentiation in the structure of supply.

Aged↗
PubMed1980

High-pressure liquid chromatographic analysis of pramoxine hydrochloride in high lipoid aerosol foam dosage form.

A rapid and quantitative method for the determination of pramoxine hydrochloride by high-pressure liquid chromatography is presented. The drug is extracted as the salt from a preparation with a high lipoid composition by partitioning it to the aqueous phase of an ether-methanol-water-acetic acid system. The extract is chromatographed on an octadecylsilane bonded packing with a methanol-water-acetic acid-methanesulfonic acid mobile phase. The time required for each separation is approximately 6 min. Analytical recoveries of 100.4 +/- 1.5% were obtained.

Aerosols↗
PubMed1980

Endocrine differentiation in mucoid carcinoma of the breast.

Mucoid carcinoma of the breast is not a single homogeneous entity. It comprises two main variants separable on structural and cytological grounds and a smaller transitional type. The salient pathological differences are detailed. One variant is usually arygrophilic and contains dense core granules of the type seen in endocrine tumours. Both endocrine and amphicrine cells have been identified in this sub-type. The relationship of this endocrine variant of mucoid carcinoma to other argryophil carcinomas (so-called 'carcinoids') of the breast is discussed.

Adenocarcinoma, Mucinous↗
PubMed1980

Asbestosis.

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Asbestos↗