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Biomedical subjects

P Langer

Publications and source records attributed to P Langer.

At least 37 records · Page 2Linked to original sources
PubMed2004

[Diagnosis and surgical treatment of insulinoma--experiences in 40 cases].

BACKGROUND AND OBJECTIVE: Most insulinomas are solitary, benign and functional neuroendocrine pancreatic tumors which give rise to manifold symptoms. Their preoperative localization is often unclear, but the cure rate after their excision is very high. It was the aim of this study to analyse and evaluate our group of patients with regard to preoperative tumor localization and overall surgical results. METHODS: Data were collected as part of prospective observations and retrospective evaluation of all patients treated for insulinoma between 1987 and 2003 at the department of visceral- thoracic- and vascular surgery at the Philipps University of Marburg. In all of them the diagnosis had been confirmed by a fasting test. RESULTS: 40 patients with an insulinoma (22 females, 18 males; average age 52 years [range 12-87 years]) had been operated. The sensitivity of preoperative localization was 65% for endoscopic ultrasound, 33% for ultrasound, 33% for computed tomography, 15% for magnetic resonance imaging and 0% for somatostatin-receptor scintigraphy. But all insulinomas were identified intraoperatively by pancreas dissection and ultrasound (IOUS). 38 patients were completely cured by excision of the tumor. CONCLUSION: After positive biochemical and fasting tests and exclusion of diffuse abdominal metastases by transabdominal ultrasound, all patients should without further preoperative investigations undergo surgical excision of the insulinoma after bidigital palpation of the pancreas and IOUS. But if laparoscopic excision is planned, endoscopic ultrasound should be undertaken preoperatively.

Adolescent↗
PubMed2004

[Multiple endocrine neoplasia type 1. Surgical therapy of primary hyperparathyroidism].

Primary hyperparathyroidism (pHPT) occurs in about 90% of patients with multiple endocrine neoplasia type 1 (MEN1). In contrast to sporadic pHPT, multiple gland disease is most common in MEN1. The appropriate surgical approach is still controversial. The aim of this study was to analyze the results of surgical therapy of pHPT in patients with genetically confirmed MEN1. In an observational study, preoperative data, operative procedures, long-term results, and a possible genotype-phenotype correlation were analyzed in patients with pHPT and genetically confirmed MEN1. According to our results, tPTX+T (total parathyroidectomy+thymectomy+autotransplantation) seems to be a more favorable surgical approach in patients with MEN1 pHPT than sDE (selective gland exstirpation) and stPTX (subtotal parathyroidectromy) without cervical thymectomy, because recurrences or persistence of the disease are rare. A prospective randomized trial is needed to compare stPTX including cervical thymectomy vs tPTX+T. A genotype-phenotype correlation could not be identified.

Chi-Square Distribution↗
PubMed2003

Prevalence of multiple endocrine neoplasia type 1 in young patients with apparently sporadic primary hyperparathyroidism or pancreaticoduodenal endocrine tumours.

BACKGROUND: The appropriate treatment for a sporadic endocrine tumour may be different from those that present as part of the multiple endocrine neoplasia type 1 (MEN1) syndrome. As primary hyperparathyroidism (pHPT) and pancreaticoduodenal endocrine tumours (PETs) are the most common organ manifestations of MEN1, the prevalence of germline mutations in the MEN1 gene was determined in young patients with apparently sporadic pHPT or PETs. METHODS: Eighteen of 705 patients with pHPT and 11 of 93 patients with PETs operated on between 1987 and 2001 had no family history of MEN1, only one organ manifestation and were aged 40 years or less at the time of diagnosis. Fifteen patients with pHPT and eight with PETs agreed to MEN1 gene mutation analysis, which was performed by single-strand conformational variant analysis and direct DNA sequencing. RESULTS: Two of 15 patients (13.3 (95 per cent confidence interval (c.i.) 1.6 to 40.4) per cent) with apparently sporadic pHPT had a MEN1 germline mutation. Both mutations were found in patients with pHPT due to multiglandular disease, whereas the remaining 13 patients had a solitary adenoma. None of the eight patients with PETs carried a MEN1 germline mutation. CONCLUSION: Sporadic pHPT due to multiglandular disease in patients younger than 40 years may represent the first organ manifestation of MEN1 despite a negative family history.

Adolescent↗
PubMed2003

From naturally occurring goitrogens to the effects of anthropogenic endocrine disruptors on the thyroid in Slovakia.

The objective is to describe the effect of mandatory and well monitored prophylaxis of endemic goitre in Slovakia with the use of iodised salt for past 50 years and previous experimental attempts to assess a possible participation of naturally occurring goitrogens in the etiology of goitre. Previous observations by others showed a striking decrease of goitre prevalence in schoolchildren as early as few years after starting the prophylaxis in Slovakia and this success has been confirmed by a European study conducted by others in mid nineties. In the meantime, however, massive industrialisation of Slovakia and environmental negligence of the administration resulted in heavy airborne and mainly waterborne pollution of the food chain in certain areas around large chemical factories by industrial waste including polychlorinated biphenyls (PCB). Since Slovakia has been recently evaluated as an iodine replete country as based on the findings of the low thyroid volume by ultrasound and high urinary iodine, it became possible to evaluate the participation of factors different from iodine deficiency in the thyroid growth. Recent field surveys including an extensive international study PCBRISK repeatedly showed highly increased blood PCB level in subjects living in the polluted area and, at the same time, increased thyroid volume by ultrasound, increased frequency of positive thyroid antibodies and impaired glucose tolerance. (Ref. 59)

Child↗
PubMed2003

[The thyroid gland in women during the reproductive age].

OBJECTIVE: To find out thyroid volume and its functional status in women in reproductive age as well as possible correlation between thyroid size and functional status and age and residential location of women. DESIGN: Project can be characterized as an epidemiological study and consists of three separate observations. SETTING: 1st Internal Clinic, UPJS, Kosice, Medical Faculty, Slovakia. METHODS: 347 women from different regions of Eastern Slovakia (160 aged 20-29 and 187 aged 30-40) were measured thyroid volume via ultrasonography and thyroid functional status by RIA TSH and anti TPO examinations. Urinary iodine was examined in 70 cases. In this part of the study correlation between thyroid size and functional status and age and residential location of women were determined. Four days after delivery thyroid volume in 99 women was measured. The volume was correlated with the number of previous pregnancies. Thyroid volume was correlated with residential location and number of pregnancies of 77 women that had not delivered in the previous year. RESULTS: Women aged 20-29 years had thyroid volume smaller than women aged 30-40 (8.78 ml/10.66 ml; p < 0.01). The size of thyroid gland was not only affected by age but also by residential location. The largest thyroid glands and increased level of anti TPO antibodies in both age groups were found in women from agricultural regions and regions close to chemical factory. The women with anti TPO antibodies had increased level of TSH as well as more frequently changed echogenity of thyroid gland. Median of urinary iodine was 13.2 micrograms/dl in both age groups and indicated sufficient iodine intake in the observed area. The volume of thyroid gland four days after delivery did not exceed 22 ml in 89.9% of cases. Significant difference in size of thyroid gland depending on number of previous deliveries was not only observed in women 4 days after delivery but also in those that had not delivered during previous year. The largest volumes were measured in secundiparous mothers. CONCLUSION: Polluted environment affects the size and functional status of thyroid gland. Environment can via this negative impact on thyroid gland influence fertility, pregnancy and fetus development in women in reproductive age.

Adult↗
PubMed2003

Thyroid function and cholesterol level: paradoxical findings in large groups of population with high cholesterol food intake.

OBJECTIVE: To compare the levels of serum cholesterol with thyroid function as estimated by the level of thyrotropin and free thyroxine with possible participation of thyroperoxidase antibodies in large number of adults examined within large field surveys focused on the evaluation of thyroid status of Slovak rural population. SUBJECTS AND METHODS: Serum level of cholesterol and thyrotropin (TSH) was estimated in a total of 2786 adults. In addition, in 2038 of them also the level of free thyroxine (FT4), total triiodothyronine (TT3), cholesterol, triglycerides and phospholipids was measured. The levels of TSH, anti-TPO and FT4 were estimated by supersensitive electrochemiluminiscent immunoassay using the automatic system Elecsys (Roche, Switzerland). RESULTS: A total of 2786 adults was stratified into 7 groups according to the range of TSH level as related to generally recognized level of thyroid function, e.g. 1. TSH <0.10 mU/L (overt hyperthyroidism, N=41), 2. TSH 0.11-0.30 mU/L (overt or subclinical hyperthyroidism, N=149), 3. TSH 0.31-2.50 mU/L (normal level, N=1750), 4. TSH 2.51-4.50 ("high normal" level, N=607), 5 TSH 4.51-6.50 (mild or incipient subclinical hypothyroidism, N=137), 6. TSH 6.51-10.00 mU/L (mild hypothyroidism, N=50), 7. TSH 10.01-99.00 mU/L (severe hypothyroidism, N=53). The average levels of cholesterol in all groups were very similar ranging from 5.53 to 6.17 mmol/L and no interrelations with TSH level were found. In addition, no considerable differences between these groups were found when considering the levels of medians, upper quartiles and 90th percentiles of individual groups. When male and female subjects were divided into age groups according to the decades, an age dependent increase of cholesterol level was found in both sexes. The fraction of 2038 subjects was divided into the same TSH related groups as defined above. Similarly as above, no considerable differences in cholesterol, triglycerides and phospholipids level were observed. However, the levels of FT4 and TT3 were significantly decreasing with the increase of TSH level which confirmed the continuing decrease of thyroid function. The frequency of positive anti-TPO in subjects with TSH >6.5 mU/l (71/86 = 82.5%) was significantly higher than that in subjects with TSH <6.5 mU/l (468/1952 = 23.9%). CONCLUSIONS: No difference in the level of cholesterol and triglycerides was found in large groups of rural adults from Slovakia with various thyroid function as estimated by the level of TSH, FT4, TT3 and anti-TPO. It is assumed that this interrelation resulted from very high cholesterol intake due to inappropriate general nutritional status of rural population resulting from the consumption of unhealthy foods.

Adult↗
PubMed2002

Renin producing neuroendocrine pancreatic carcinoma--a case report and review of the literature.

A 44 year old male patient presented with severe hypertension. The diagnostic work-up revealed elevated levels of plasma renin activity (about 10 times the upper limit of normal) in the presence of normal plasma aldosterone levels and serum potassium concentrations. Renovascular disease was excluded by angiography. Selective renal vein sampling did not show any renin gradient. CT-scans of the abdomen demonstrated normal morphology of the kidneys and adrenals but revealed a big mass in the pancreatic corpus and tail with infiltration of the splenic vein and the presence of enlarged local lymph nodes. The endocrine nature of the pancreatic mass was further supported by a positive octreotide scintigraphy scan. Surgical removal of the tumor by left sided pancreatectomy combined with splenectomy resulted in rapid normalization of elevated renin concentrations as well as blood pressure. Histological examination of the tumor tissue revealed the presence of a neuroendocrine pancreatic carcinoma. Highly (x 70) elevated renin levels were detected by radioimmunoassay in the tumor tissue. To our knowledge this is the first renin-producing neuroendocrine pancreatic carcinoma described in the literature. The present paper describes the case in detail and reviews the available literature on clinical symptomatology, diagnosis and treatment of renin-producing tumors.

Adult↗
PubMed2002

Familial ACTH-independent Cushing's syndrome with bilateral macronodular adrenal hyperplasia clinically affecting only female family members.

Primary adrenal hyperplasia, which may occur as a familial disorder, is a rare cause of ACTH-independent Cushing's syndrome. In most of these cases the underlying pathology is primary adrenocortical micronodular dysplasia. Very few cases of familial Cushing's syndrome due to primary macronodular adrenal hyperplasia have been described. We report a family with seven affected family members. The pedigree indicates an autosomal dominantly inherited disorder. Interestingly only female family members developed the clinically apparent syndrome. The only available obligatory male gene carrier failed to adequately suppress his plasma cortisol level on overnight dexamethasone suppression test. His adrenal glands showed nodular enlargement on abdominal computed tomographic imaging. Screening of the MEN 1 gene and genetic analysis of the hot spot regions of the GNAS 1 (codons 201 and 227) and GNAI 2 (codons 179 and 205) genes did not show any mutations in the constitutional DNA or the adrenal tissue DNA of the index patient. In conclusion, this family is the largest kindred reported in the literature with ACTH-independent Cushing's syndrome due to autosomal dominant inherited macronodular adrenocortical hyperplasia. Four currently alive and affected family members in two generations and further careful observation of the yet unaffected members of the third available generation might offer the opportunity to identify the still unknown gene defect in the future.

Adrenal Hyperplasia, Congenital↗
PubMed2001

Regio- and diastereoselective cyclization reactions of free and masked 1,3-dicarbonyl dianions with 1,2-dielectrophiles.

Despite their simplicity and synthetic usefulness, cyclisation reactions of 1,3-dicarbonyl dianions with 1,2-dielectrophiles are problematic, since both dianions and 1,2-dielectrophiles are highly reactive compounds (low reactivity matching). In addition, 1,2-dielectrophiles are often rather labile, and reactions with nucleophiles can result in polymerisation, decomposition, formation of open-chained products, elimination or SET-reactions. These intrinsic limitations can be overcome by a proper reactivity tuning and by the use of electroneutral dianion equivalents (masked dianions) in Lewis acid catalysed reactions. The cyclisations reported herein allow for an efficient, regio- and stereoselective one-pot synthesis of biologically relevant ring systems.

Journal Article↗
PubMed2001

Regio- and diastereoselective synthesis of 2-alkylidenetetrahydrofurans by domino SN/SN' and SN/SN reactions of 1,3-dicarbonyl dianions.

The domino C,O-cyclodialkylation reaction of dilithiated 1,3-dicarbonyl compounds with 1,4-dibromo-2-butene resulted in regio- and diastereoselective formation of 2-alkylidene-5-vinyltetrahydrofurans. The cyclization of 1,3-dicarbonyl dianions with 1-bromo-2-chloroethane regio- and diastereoselectively afforded 2-alkylidenetetrahydrofurans under thermodynamic reaction control.

Journal Article↗
PubMed2001

Synthesis of radialene-shaped pyrroles by multiple-anion-capture reactions of 1,3-dianions.

A new multicomponent reaction (multiple-anion-capture reaction) of 1,3-dianions with nitriles and oxalic acid-bis(imidoyl)chlorides is reported. This process allows for an efficient and regioselective synthesis of a variety of radialene-shaped pyrroles which constitute structurally new and interesting heterocyclic systems. The cyclization products can be considered as aza-analogues of the pharmacologically relevant substance class of 3-acetyltetramic acids. A rationalization of the experimental results is given based on quantum chemical computations.

Anions↗
PubMed2001

Chemo-, regio-, and stereoselective cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with alpha-chloroacetic acid chlorides and alpha-chloroacetic acetals.

Treatment of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with alpha-chlorocarboxylic acid chlorides resulted in chemo- and regioselective formation of 6-chloro3,5-dioxo esters, which were regioselectively converted into functionalised 3(2H)furanones. Chemo- and regioselective condensation of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with alpha-chloroacetic dimethyl acetal afforded 6-chloro-5-methoxy-3-oxo esters, which could be regio- and stereoselectively transformed into 2-alkylidene-4-methoxytetrahydrofurans.

Journal Article↗
PubMed2001

Efficient synthesis of gamma-alkylidenetetronic esters by sequential Lewis acid catalyzed.

A new approach for the synthesis of gamma-alkylidenetetronic acids and esters is reported which involves Me3SiOTf-catalyzed, regio- and stereoselective cyclization of 4-alkoxy-1,3-bis(trimethylsilyloxy)-1,3-butadienes with oxalyl chloride. The alpha-hydroxy group of the butenolides is efficiently functionalized by palladium-catalyzed cross-coupling reactions via the corresponding enol triflates.

Journal Article↗
PubMed2001

Regio- and stereoselective synthesis of Nor-nonactinic acid derivatives--kinetic reaction control in the Lewis acid mediated domino reaction of 1,3-dicarbonyl dianions with 1-bromo-2,3-epoxypropanes.

Reaction of 1,3-dicarbonyl dianions with epibromohydrin derivatives results in formation of functionalized 2-alkylidene-5-hydroxymethyltetrahydrofurans. These reactions proceed by chemoselective attack of the dianion onto the carbon attached to the bromine atom and subsequent nucleophilic attack of the resultant monoanion onto the epoxide. The cyclization products, which were formed with very good regio- and stereoselectivities, are of pharmacological relevance and represent versatile building blocks for the synthesis of natural products.

Journal Article↗
PubMed2001

Direct transformation of silyl enol ethers into functionalized allenes.

The first elimination reactions of silyl enol ethers to lithiated allenes are reported. These reactions allow a direct transformation of readily available silyl enol ethers into functionalized allenes. The action of three to four equivalents of lithium diisopropylamide (LDA) on silyl enol ethers results in the formation of lithiated allenes by initial allylic lithiation, subsequent elimination of a lithium silanolate, and finally, lithiation of the allene thus formed. Starting with amide-derived silyl imino ethers, lithiated ketenimines are obtained. A variety of reactions of the lithiated allenes with electrophiles (chlorosilanes, trimethylchlorostannane, dimethyl sulfate and ethanol) were carried out. Elimination of silanolate is observed only for substrates that contain the hindered SiMe2tBu or Si(iPr)3 moiety, but not for the SiMe3 group. The reaction of 1,1-dilithio-3,3-diphenylallene with ketones provides a convenient access to novel 1,1-di(hydroxymethyl)allenes which undergo a domino Nazarov-Friedel-Crafts reaction upon treatment with p-toluenesulfonic acid.

Journal Article↗
PubMed2001

Prospective controlled trial of a standardized meal stimulation test in the detection of pancreaticoduodenal endocrine tumours in patients with multiple endocrine neoplasia type 1.

BACKGROUND: Use of a standardized meal stimulation test has been recommended for the early diagnosis of pancreaticoduodenal endocrine tumours (PETs) in patients with multiple endocrine neoplasia type 1 (MEN 1). The diagnostic value of this test was re-evaluated. METHODS: In a prospective, controlled trial 58 standardized meal stimulation tests (563 kcal) were performed in 12 patients with MEN 1 and histologically, biochemically and/or radiologically confirmed PETs (group 1), 11 carriers of an MEN 1 mutation with no evidence of PETs (group 2) and in 27 healthy controls (group 3). Serum pancreatic polypeptide (PP) and gastrin concentrations were measured before and during the test meal. RESULTS: Patients in group 1 had significantly higher mean basal serum PP and gastrin concentrations than patients in group 2 and controls (P < 0.05). In all three groups an increase in serum PP was observed after meal stimulation, but there was no significant difference between the groups. No increase in gastrin level was found in any of the groups after meal stimulation. CONCLUSION: The standardized meal stimulation test does not reliably indicate the presence of PETs in patients with MEN 1, whereas raised basal serum PP and gastrin levels do. The expensive and time-consuming meal test can be excluded from MEN 1 screening programmes.

Adult↗