Biomedical subjects

B Mann

Publications and source records attributed to B Mann.

At least 55 records · Page 3Linked to original sources

PubMed1998

[Surgical therapy of benign thyroid gland diseases].

Operations due to benign thyroid diseases are one of the most common elective surgical procedures performed in Germany. In the majority of cases, the preoperative determination of the serum thyrotropin concentration and an ultrasound of the thyroid region are sufficient preoperative investigations. In cases of thyroid functional disorders a scintigram should be additionally performed. Indications for operation in nodular goiter are local, mechanical compression, suspicion of malignancy and focal or disseminated autonomy. In Graves' disease the indication for operation is usually recurrent hyperthyroidism after medical treatment. In endemic nodular goiter the morphology of the nodular thyroid tissue is the guideline for resection; i.e. all nodules have to be removed. In Graves' disease the function of the remaining thyroid tissue is essential. The standardized subtotal resection with remaining tissue around the hilus, which frequently barries nodules, should be avoided. Instead a selective resection which takes the individual morphology and function of the diseased thyroid tissue into account should be favorized. With this operative technique the surgeon will have frequently direct contact with the recurrent nerve and the parathyroids. It is documented, that intraoperative visualisation of the recurrent nerve decreases not only the rate of permanent nerve damages but increases as well the completeness of resection. Additionally, ligation of the inferior thyroid artery decreases the incidence of residual or recurrent disease without enlarging the risk of postoperative parathyroiprive hypocalcemia. An individual follow-up with iodine and/or thyroxine replacement therapy is an indispensable component of the surgical therapeutic approach. The target of thyroxine substitution in patients after resection due to benign thyroid diseases is a physiologic serum thyrotropin concentration (0.3 to 4.0 mU/l).

Arteries↗

PubMed1998

[The concept of "microsurgical" technique in medullary thyroid carcinoma].

Medullary thyroid carcinomas (MTC) metastasize early into the regional lymph nodes. Calcitonin is a highly specific and sensitive marker for these tumors, which is feasible for follow-up and for screening. Additionally, in families with hereditary MTC the responsible mutations of the RET-proto-oncogene can be identified, and prophylactic surgery can be provided. We operated on 127 patients for MTC, 114 of whom had diagnosed carcinomas; 13 operations were performed with prophylactic intention. A total of 101 patients needed microsurgical dissection of the cervical compartments. Of these, 31% could be cured, and a further 46% showed postoperatively normalized basal calcitonin concentrations. Thirteen patients who needed mediastinal dissection had persistent increased levels of pentagastrin-stimulated or basal calcitonin values. All patients who underwent prophylactic surgery could be cured.

Adult↗

PubMed1998

[Controlling in a surgical university clinic exemplified by bilateral thyroid gland resection].

We calculated the overall costs of all patients who had bilateral thyroid resections due to benign diseases between 1995 and 1997 in a process costing analysis. The operating costs for an bilateral thyroid resection were 5205 DM, resulting in a loss of 410 DM/per case. The major cost factors were personnel costs (33%), operating costs on the ward (32%), and shared overhead costs (24%). Consequently, the main efforts for cost reduction were achieved by reducing the hospital stay (12.6 days in 1995 resulting in 7755 DM total costs; 6.3 days in 1988 resulting in 4712 DM). Saving in personnel costs by reducing operating time is not feasible in a university department due to its obligation of training. Overhead costs need to be analysed in detail, because this is a hitherto neglected domain, where costs can be saved without damaging the quality of the surgical therapy.

Cost Control↗

PubMed1998

[Benign thyroid gland diseases in childhood and adolescence--early indications for surgical therapy].

Thyroid diseases in childhood and adolescence are mainly diffuse goiters due to iodine deficiency, which should be treated conservatively. Thyrotoxicosis, in the majority due to Graves' disease, is usually treated conservatively, and remissions can be expected in only 20%. Our prospective data from 21 patients under 20 years of age show that primary surgery is favored in young patients because of its prompt and permanent success. Minimal postoperative morbidity is the precondition for this approach. Preoperative conservative treatment for more than 2 years causes a significantly higher incidence of persistent ophthalmopathy postoperatively. Thyroid nodes in children are malignant in 20-30%. Consequently, all children and adolescents with nodular thyroid disease should have a primary lobectomy.

Adolescent↗

PubMed1997

Low O-acetylation of sialyl-Le(x) contributes to its overexpression in colon carcinoma metastases.

Two factors potentially determining the consistent overexpression of sialyl-Le(x) antigen in colon carcinoma and metastases were investigated: (i) the expression of the mucins MUC1 and MUC2, known to carry sialyl-Le(x), by Northern blotting; (ii) the extent of sialic acid O-acetylation, by Western blotting and HPLC. RNA and sialyl-Le(x)-positive mucins were purified from normal colonic mucosa (N), primary carcinomas (T) and their liver metastases (M). Northern blots showed that mRNA expression both of MUC1 and of MUC2 decreases during the progression of the disease, and is lowest in metastatic tissue. The expression of mucin-bound sialyl-Le(x) increased strongly from N to T and, to a lesser extent, to M. After alkali treatment of the mucins these differences disappeared, indicating that the total amount of mucin-bound sialyl-Le(x) is the same in the 3 types of tissues. The O-acetylation of mucin-bound sialyl-Le(x) gradually decreased from N to M. HPLC analysis showed that in N about 70%, in T 45% and in M only 20% of mucin-bound sialic acids are O-acetylated. Thus, the increase of sialyl-Le(x) detectable during colon-carcinoma progression is due to diminished O-acetylation and not to increased expression of mucin protein cores. The decrease of O-acetylation is therefore the primary chemical alteration contributing to colon carcinoma-associated overexpression of sialyl-Le(x).

Acetylation↗

PubMed1997

MUC2 gene suppression in human colorectal carcinomas and their metastases: in vitro evidence of the modulatory role of DNA methylation.

The development of the majority of colorectal carcinomas is associated with a diminished expression of the intestinal mucin MUC2 in the tumor cells. The significance and the mechanism of this alteration are not yet known. We sought to determine the molecular basis of this tumor-associated change and to investigate the extent to which it might also relate to metastases. MUC2 gene expression was compared in normal (N), carcinomatous (T), and metastatic tissues (M) from nine patients by immunohistochemistry, in situ hybridization, and Northern blotting. Immunohistochemistry and in situ hybridization showed consistently lower amounts of the expressed protein and mRNA in T and in M than in N; quantitative analysis by Northern blotting confirmed that the differences between MUC2 mRNA expression between N, T, and M were significant, the expression in metastases being less than 5% of that in the normal colonic tissue. The influence of DNA methylation as a possible regulatory mechanism of MUC2 gene expression was tested after the 5' and 3'-regions flanking the first exon of MUC2 were recovered from a genomic DNA library and used as probes in Southern blot. The DNA was isolated from colon carcinoma cell lines expressing MUC2 strongly (LS174T) or moderately (T84) and from that which was nonexpressing (Colo 205), and it was digested with the methylation-sensitive enzyme HpaII. The Southern blot patterns indicated that the increased methylation in the promoter region was concomitant with the decrease of MUC2 mRNA expression. Methylation of the promoter region ligated into a reporter vector suppressed the expression of the luciferase reporter gene in the three investigated cell lines. Furthermore, the expression of MUC2 gene was enhanced by treating the MUC2-expressing colon carcinoma cells with 5-aza-2'-deoxycytidine, a methylation-inhibiting agent. To our knowledge this is the first report to show that: (a) MUC2 gene is strongly suppressed in liver and lymph node metastases of colorectal carcinomas, and (b) suppression of MUC2 gene in colon carcinoma cells in vitro is associated with methylation of the promoter region.

Base Sequence↗

PubMed1997

[Is preoperative scintigraphy in euthyroid nodular goiter necessary?].

Preoperative thyroid isotope scan would influence the operative procedure and the perioperative management in patients with nontoxic goiter only if it raises suspicion of malignancy. However, the scintigram shows significantly lower sensitivity and specificity in the detection and prediction of malignant nodules in the thyroid gland than the ultrasound examination. Thyroid isotope scan is more expensive than ultrasonography, and its routine use in the investigation of nontoxic nodular goiter should be abandoned.

Cost-Benefit Analysis↗

PubMed1997

[Value of femoral bifurcation transposition for revascularization of the thigh].

Fifty-seven patients with 60 transpositions of the femoral artery bifurcation were prospectively analysed. This operation provided limb salvage in 95% and a sufficient revascularisation in 88% after the operation and 81% during follow-up 18 (6-28) months. The transposition of the femoral artery bifurcation is a reasonable operation in patients with a relevant stenosis of the profunda femoris. It does not need alloplastic patches, the saphena vein is conserved and, in our series, subsequent distal bypass was required in less than 10%.

Aged↗

PubMed1996

Prospective study of hand-sutured anastomosis after colorectal resection.

A total of 370 patients underwent colorectal resection: 320 had a primary single-layer seromucosal anastomosis without a protective colostomy, 22 had Hartmann's procedure and 28 abdominoperineal resection. There were 260 elective procedures and 110 patients had peritonitis and/or bowel obstruction at the time of surgery. Overall the mortality rate was 2.7 per cent, the morbidity rate was 18.3 per cent and clinical anastomotic leak rate 3.4 per cent. After elective operation, the leak rate for intraperitoneal anastomosis was 0.6 per cent and for low extraperitoneal anastomosis 7 per cent. The mortality rate was 1.2 per cent and morbidity rate 11.9 per cent. Patients with peritonitis had a significant increase in morbidity rate (46 per cent) in comparison with those having elective surgery (chi 2 = 31.5, 1 d.f., P < 0.0001). Patients who had bowel obstruction and no bowel preparation had a significantly higher morbidity rate of 26 per cent and mortality rate of 7 per cent, compared with those having an elective procedure (chi 2 = 11.2, 1 d.f., P < 0.001; chi 2 = 8.7, 1 d.f., P < 0.005 respectively). Patients having palliative surgery had the highest mortality rate (19 per cent), compared with those operated on with curative intent (1.5 per cent) (chi 2 = 28.7, 1 d.f., P < 0.0001). Cost-saving hand-sutured anastomosis is effective and, in experienced hands, technically feasible after all kinds of colorectal resection and should remain the standard in colorectal surgery.

Adult↗

PubMed1996

Thyroid morphology and function after surgical treatment of thyroid diseases.

In 1992 we performed a prospective study with 300 patients after thyroid resection. Indication for the operation was a benign nodular goiter in 280 cases, Graves' disease in 11 cases and a differentiated thyroid carcinoma in 9 cases. 269 patients (89.6%) returned for a follow-up visit which contained an ultrasound of the thyroid region and a determination of the serum thyrotropin concentration. Patients with less than 10 ml had a thyroxine replacement of 100 yg daily for six months. This therapy was discontinued for the next three months and they received their follow-up nine months after the operation. All other patients with benign diseases had their follow-up without thyroxine replacement eight weeks after the operation. The mean remnant volume was 2.4 ml for selective resected lobes, 0.8 ml after near total resection and 0.2 ml after lobectomy. We found residual or recurrent nodular tissue in 7.2% of the partially resected lobes. Visualization of the recurrent nerve and ligation of the inferior thyroid artery reduced the risk of nodular tissue in the remnant thyroid tissue significantly. Only 153 patients (62%) were treated according to our postoperative treatment schedule. Thyroxine replacement therapy was given to 96 patients at the time of their follow-up. 34% of the patients without replacement therapy had signs of insufficient hormone production of the remnant thyroid tissue. However, 22% of the patients under thyroxine replacement therapy showed signs of iatrogenic subclinical hyperthyroidism. We found a significant correlation between the volume of the remnant tissue and the serum thyrotropin concentration in patients without continuous thyroxine replacement. The corresponding calculated volume for a functionally potent remnant thyroid volume was 7.3 ml. This value was significantly higher in patients with both inferior thyroid arteries ligated at 9.8 ml. An individual postoperative therapy with iodine and/or thyroxine, which results in neither a high rate of thyrotropin elevation nor an unnescessary and undesirable part of the patients with suppressed serum thyrotropin concentrations is an indispensable component of the surgical treatment of benign nodular thyroid disease in areas of endemic iodine deficiency. As a result of this study we changed our postoperative treatment schedule. Patients with less than 10 ml remnant thyroid volume will have a continuous replacement therapy with a reduced dose of 75 yg thyroxine daily.

Adenoma↗

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↗