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Biomedical subjects

F Jockenhövel

Publications and source records attributed to F Jockenhövel.

At least 55 records · Page 3Linked to original sources
PubMed1994

Polymorphism of human pituitary FSH: analysis of immunoreactivity and in vitro bioactivity of different molecular species.

Follicle-stimulating hormone is known to be highly heterogeneous in serum and in the pituitary. In the present study, we have partially separated different molecular species of human pituitary FSH and characterized their immunoreactivity and in vitro bioactivity. Pooled extracts of male (n = 15) and female (n = 9) human pituitary glands were chromatographed on a column of Sephacryl S-200 and FSH-containing fractions were fractionated by chromatofocusing in the pH range 4-6. FSH was measured in the individual fractions by an in vitro bioassay, based on the FSH-dependent aromatase activity of immature rat Sertoli cells, and by the following methods based on commercial kits: radioimmunoassay (RIA), immunofluorimetric assay (IFMA), immunoradiometric assay (IRMA), immunoenzymometric assay (IEMA). In each assay, the kit standard, calibrated against the 2nd International Reference Preparation (IRP) 78/549, and the International Standard (IS) 83/575 were run in parallel. The relative potencies of the kit standards in terms of IS 83/575 were: IFMA 3.08, IRMA 1.62, RIA 2.42, IEMA 1.45 and bioassay 1.14. After chromatofocusing, pituitary FSH eluted mostly in fractions with pH approximately 4.5, without sex-related differences. In both sexes approximately 25% of bioactive material showed a pI < 4 and eluted with 1 M NaCl. Although the same IS 83/575 was used in the various assays, the profiles of immunoreactive FSH were significantly different. The highest intermethod variability was observed in the case of male pituitary FSH. The relative biopotency of the different molecular species of FSH did not appear to change according to their pI but, rather, varied with the assay method and the standard.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Biological and immunological properties of the international standard for FSH 83/575: isoelectrofocusing profile and comparison with other FSH preparations.

The new international standard for FSH, IS 83/575, has been analyzed, after isoelectric focusing separation, by Sertoli cell in vitro bioassay, radioligand receptor assay and two highly specific immunometric assays. Its molecular composition was then compared with the isoelectric focusing profiles obtained from the fractionation of the reference preparation 2nd IRP 78/549 and from pools of human male and female pituitary extracts and male and female sera. The results showed that > 80% of immunoreactive and bioactive FSH in the IS 83/575 has a pI value < 4, while such very acidic material was represented much less in the other FSH preparations tested. All the immunoreactive material contained in the IS 83/575 was shown to be capable of receptor binding and bioactivity in vitro. A generally good correspondence between IEF profiles obtained by bioassay and by immunofluorimetric assay was evident in the case of IS 83/575, 2nd IRP 78/549 and pituitary extracts, although the profiles recorded by immunofluorimetric assay were rather smooth and more isoforms were detected by bioassay. A striking discrepancy between immunoreactive FSH and bioactive FSH was observed after isoelectric focusing fractionation of the serum pools, in which some bioactive material was not detected by immunofluorimetric assay and some of the immunoreactive FSH peaks were devoid of bioactivity, indicating that serum contains inhibitors of FSH action and that immunometric assays based on monoclonal antibodies may miss some bioactive FSH isoforms.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

[Questions and answers on the epidemiology and etiology of goiter].

Goitre defines any enlargement of the thyroid independent of its cause. Worldwide iodine deficiency is the single most common cause of a goitre. However, before iodine deficiency is established, other thyroid diseases need to be ruled out. Very rarely increased production of TSH (secondary hyperthyroidism) or of hormones with TSH activity (e.g. hCG producing tumours), inborn errors of iodine metabolism, and defects of the thyroid hormone receptor (thyroid hormone resistance) are the cause of a goitre. Furthermore, malignancy of the thyroid and autoimmune disease (e.g. Grave's disease) may lead to a thyroid enlargement. Still, worldwide more than 90% of the 200 million patients with goitre suffer from iodine deficiency. In Germany, as in only few other European countries which lack any nation-wide prophylactic iodine supplementation, goitre is endemic with a prevalence of about 25%. The classical concept on the mechanism of iodine deficiency induced goitre is based on decreased thyroid hormone synthesis in the presence of iodine depletion, which leads to increased production of TSH, stimulating thyroidal growth. Recent in vitro findings using thyroid cell cultures expand this concept by demonstrating that TSH regulates the differentiation and function of thyroid cells and may induce hyperplasia, but not cell proliferation. In contrast to TSH, the locally produced growth factors IGF I (insulin-like growth factor I) and EGF (epidermal growth factor) stimulate thyroid cell proliferation. Intrathyroidal iodine antagonises the effects of IGF I and EGF and simultaneously stimulates transforming growth factor beta (TGF-beta), which inhibits thyroid cell proliferation. Thus, intrathyroidal iodine appears to regulate thyroidal growth by controlling proliferation stimulating (IGF I, EGF) and proliferation inhibiting (TGF-beta) growth factors. Though these new insights fill several gaps of the classical concept on the pathogenesis of endemic goitre, open questions remain.

Adolescent↗
PubMed1993

[Management of the cold thyroid nodule and thyroid malignancy].

The evaluation and management especially of cold thyroid nodules remains an area of controversy. The past decade has witnessed two important advances. The increased availability of fine-needle aspiration of thyroid nodules has altered the clinician's approach to this disease, and provides for the single most precise method for selecting appropriate patients for surgery. The introduction of high-resolution thyroid ultrasonography provides for anatomic definition that is clearly superior to thyroid scintigraphy. However, radionuclide imaging remains critical for determining the functional status of abnormal thyroid tissue. This review attempts to provide a practical approach to the evaluation and management of the thyroid nodule. Only rare data exists concerning the therapeutic approach of cold thyroid nodules and non-toxic nodular goitre. There seems to be a size-reducing effect by thyroxin-treatment, but no data are reported from iodine deficient areas. Concerning the treatment of differentiated thyroid carcinoma total thyroidectomy combined with eradication of remaining thyroid tissue with iodine 131 is usually preferred. In case of smaller or occult carcinoma various modes of uni- or bilateral subtotal resection are used. Chemotherapy is of little use in treating differentiated thyroid carcinoma and remains as a last possibility if usual approaches are no longer effective. To control local-invasive growth of anaplastic thyroid carcinoma combined treatment with mitoxantrone and hyperfractionated irradiation seems to be a successful approach.

Biopsy, Needle↗
PubMed1992

Cervical pheochromocytoma: a rare localization and a difficult diagnosis.

A 45-year-old hypertensive female with insulin-treated diabetes mellitus presented to our clinic with elevated urinary norepinephrine (NE) concentrations and a negative 131-metaiodobenzylguanidine (MIBG) scintigraphy, errouneously limited to the abdomen, for evaluation of a pheochromocytoma (Pheo). Despite antihypertensive medications blood pressure remained highly variable and frequently elevated. Further biochemical testing, including a glucagon provocation test and a clonidine-suppression test, revealed autonomous NE secretion. In order to avoid repeat MIBG-scintigraphy, other non invasive imaging techniques were performed, including real time sonography (7.5 MHz) of the neck which revealed a tumor. Fine needle aspiration of this tumor tissue demonstrated cells compatible with Pheo. Histology and immunohistochemistry of the excised tumor confirmed the diagnosis of Pheo. After surgical removal of the tumor, urinary and plasma NE levels normalized. Without any medication the blood pressure of the patient was now only slightly hypertensive. Only half of the daily insulin dose was needed to maintain the patient euglycemic.

Adrenal Gland Neoplasms↗
PubMed1992

Conservative and surgical management of incidentally discovered adrenal tumors (incidentalomas).

Of 50 patients with incidentalomas (INC), 18 were adrenalectomized and in 18 patients the INC was left in place. For 14 patients clinical data were insufficient for evaluation. Follow-up investigation of the 18 unoperated subjects 11-101 months (median 32.2) after the diagnosis had been made revealed unchanged size of the INC [initially 2.1 +/- 0.8 cm (mean +/- SD) at follow-up 2.0 +/- 1.0 cm]. Cushing's syndrome developed in one patient, which was not evident at the initial discovery of the INC 32 months before. "Pre-Cushing's Syndrome" was detected in 1 patient and confirmed in a second who had displayed a pathologically high dose dexamethasone suppression test 101 months before. In addition, 3 male patients with a hitherto unknown mild subclinical defect of 21-hydroxylase activity were identified. The remaining 12 patients had normal endocrine activity of their adrenals. Eighteen patients were adrenalectomized with an average tumor size of 3.96 +/- 1.88 cm. Histologically, 10 (52%) adenomas were observed, including 3 with signs of hypercortisolism. Adrenal hyperplasias were observed in 2 patients, metastasis in 1 patient. 31.5% of the INC which were removed were nonmalignant tumors of other than adrenal origin. We conclude that initially endocrinologically inactive adrenal tumors can eventually develop autonomous endocrine activity and therefore need to be reexamined at regular intervals. Conservative management with regular follow-up investigations is the preferable treatment for small incidentalomas when endocrine over-activity has been excluded and no indications of malignancy exist. Based on these observations and the literature a diagnostic and therapeutic strategy is presented.

Adrenal Cortex Function Tests↗
PubMed1991

Variations in semen parameters from fathers.

Semen volume, pH, sperm characteristics and the ejaculate content of six compounds secreted by the epididymides, prostate and seminal vesicles are presented for several semen samples from 25 men (mean age 31 years) who, without clinical assistance, had fathered children within the previous 29 months. There was a large variation both within and between individual's samples for concentrations and amounts per ejaculate of all parameters except pH. The range including 96% of all values from these fertile men are presented as standards against which samples from infertile men could be compared. Lower limits (combined arithmetic means minus twice the combined within- and between-father standard deviation) were: for semen volume, 1.9 ml; for semen pH, 7.4; for total sperm count, 39 X 10(6); for normal morphological forms, 42%; for motility (WHO grades) a, 4%; b, 19%; c, 1%; d, 19%; for curvilinear velocity, 27 microns/s; for total glucosidase, 27 mU/ejaculate; for neutral alpha-glucosidase, 17 mU/ejaculate; for L-carnitine, 0.4 mumol/ejaculate; for glycerophosphocholine, 2.4 mumol/ejaculate; for fructose, 15 mumol/ejaculate; for citrate, 30 mumol/ejaculate; for zinc, 2.8 mumol/ejaculate.

Adult↗
PubMed1991

Directly iodinated rat relaxin as a tracer for use in radioimmunoassays.

A newly developed, specific, sensitive and reliable RIA for rat relaxin is described. Radioiodinated rat relaxin, with a specific activity of 22 to 37 kBq/micrograms, was prepared from purified authentic ovarian rat relaxin using the chloramine T method. Polyclonal rat relaxin antiserum was raised in rabbits. Assay sensitivity was 30 pg/tube. Intra- and interassay coefficients of variation were 8% and 13%, respectively. Initial experiments demonstrated rising concentrations of rat relaxin in pregnant rats. Serum of adult male or non-pregnant female rats contained undetectable levels of rat relaxin. The assay is suitable for measurements of rat relaxin in biological fluids, thus making the assay a valuable tool for further studies on the physiology of relaxin.

Animals↗
PubMed1990

A portable digital data recorder for long-term monitoring of scrotal temperatures.

The application of a new, miniaturized portable digital data recorder "Thermoport" (Institute for Reproductive Medicine, Münster, West Germany) for continuous determination of scrotal temperatures revealed great variations of scrotal temperature during 24 hours in normal men. Maximum temperatures approached body core temperatures. Mean scrotal temperatures of 10 normal men rose during sauna from 32.72 +/- 0.23 degrees C to 37.53 +/- 0.38 degrees C. During treadmill running, scrotal temperatures increased by more than 2.5 degrees C. Minimal scrotal temperatures were increased in some men with varicocele compared with normal fertile men indicating impaired cooling mechanisms. The continuous temperature measurements facilitate assessment of temperature dynamics. The miniaturized design of the Thermoport makes it suitable for routine use in outpatients of infertility clinics, in occupational medicine for evaluation of heat hazards, and for investigations of body temperatures under various experimental conditions.

Adult↗
PubMed1990

'9 + 0' axoneme in spermatozoa and some nasal cilia of a patient with totally immotile spermatozoa associated with thickened sheath and short midpiece.

A patient is described with 100% immotile spermatozoa. The sperm cells lack the central pair of microtubules or the complete axoneme. This defect is associated with a thickened fibrous sheath and a shortened midpiece containing defective mitochondria. Fifteen per cent of the nasal cilia of this patient lack the central pair of microtubules. Eighteen similar cases have been described in the literature suggesting that this association of ultrastructural defects may be considered a syndrome.

Adult↗
PubMed1990

Bio and immuno-activity of FSH in serum after intramuscular injection of highly purified urinary human FSH in normal men.

The pharmacokinetics of a human FSH preparation widely used in clinical practice was evaluated in healthy male volunteers whose endogenous FSH was suppressed by 19-nortestosterone injections. 9.7 h following intramuscular injection of 150 IU FSH the mean immunoreactive peak concentration over baseline was 3.8 IU/1. Injection of 450 IU FSH led to a mean immunoreactive peak level of 10.4 IU/1 at 9.8 h. Mean half-life was 24.6 h (150 IU FSH) and 32.6 h (450 IU FSH). Serum bioFSH concentrations were suppressed below the detection limit after injection of the 19-nortestosterone and rose to preinjection levels after administration of FSH. Mean bioactive peak level for the 450 IU FSH was 7.3 IU/1 FSH at 7.4 h. The half-life of bioFSH was calculated to be 13.4 h and is considerably shorter than the half-life of immunoFSH. Serum inhibin levels were suppressed by 19-nortestosterone and did not change significantly after injection of the FSH preparation, suggesting that the FSH dose was insufficient to elicit this biological response. It is concluded that the currently used dose regimen for the treatment of male hypogonadism is inadequate for maintenance of serum bioFSH levels in the normal range.

Adult↗
PubMed1990

Improvement in the assessment of human epididymal function by the use of inhibitors in the assay of alpha-glucosidase in seminal plasma.

Seminal alpha-glucosidase has been used clinically as a marker of epididymal function. In this study enzyme inhibitors were used to increase the specificity of the human seminal alpha-glucosidase assay and improve its diagnostic value as an indicator of distal epididymal occlusion in cases of azoospermia. Sodium dodecylsulphate was added to the sample to eliminate the interfering acid isoenzyme secreted by the prostate gland, and castanospermine was used with semen pools to provide a semen blank for the assay by eliminating non-glucosidase-regulated degradation of the substrate. With both inhibitors included in the assay, glucosidase activity in semen samples from 17 fathers was measured to provide reference values for the clinic (lower threshold 18 mU per ejaculate). With the improved assay glucosidase was non-detectable in 8 out of 11 cases of proven and 5 out of 8 cases of suspected ductal obstruction; other azoospermic patients with distal occlusion had values below 11 mU per ejaculate.

Acarbose↗