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Biomedical subjects

H Zwicker

Publications and source records attributed to H Zwicker.

At least 19 recordsLinked to original sources
PubMed1996

Effect of methimazole with or without exogenous L-thyroxine on serum concentrations of thyrotropin (TSH) receptor antibodies in patients with Graves' disease.

Medical treatment of Graves' disease involves use of antithyroid drugs with or without the addition of exogenous L-T4. There have been conflicting reports as to whether the addition of T4 reduces TSH receptor antibodies and improves remission rates more than antithyroid drugs alone. To further examine the effect of drug therapy on serum concentrations of TSH receptor antibodies. 70 patients with Graves' disease were treated with methimazole (Tapazole) alone until they were euthyroid. Then they were randomized to receive either: 1) methimazole alone in a dose sufficient to normalize TSH (0.3-5.4 mIU/L; Group 1); 2) 30 mg methimazole daily plus sufficient T4 (Synthroid) to maintain TSH in the high-normal range (2.0-5.4 mIU/L; Group 2); or 3) 30 mg methimazole daily plus sufficient T4 to suppress TSH to below 0.6 mIU/L (Group 3). The duration of treatment in all groups was 18 months. At baseline and after 6 and 18 months, TSH receptor antibodies were measured both by the ability of patients' sera to stimulate cAMP production by FRTL-5 cells (thyroid-stimulating Ig) and by the ability of patients' sera to inhibit binding of radiolabeled TSH to solubilized porcine thyroid membranes (TSH-binding, inhibiting Ig). Thyroid-stimulating Ig(TSI) and TSH-binding, inhibiting Ig(TBII) concentrations were similar among the three groups at baseline. Mean baseline TSI (expressed as the percent of normal control) for all patients combined was 306 +/- 21%. Mean baseline TBII (expressed as percent inhibition of TSH binding) was 38 +/- 2%. TSI was elevated in 85% and TBII was elevated in 75% of patients at baseline. After 18 months, TSI was elevated in 64% of patients, and TBII was elevated in 28%. Serum TSI decreased by 36 +/- 5% during the study, and there was no significant difference in the degree of reduction among the three groups (P = 0.99). Serum TBII decreased by 59 +/- 3%, and there also was no significant difference among the groups (P = 0.83). At baseline, serum TBII correlated with free T4 (r = 0.33, P < 0.01), total T3 (r = 0.55, P < 0.01), and thyroid size (r = 0.35, P < 0.01). There was no correlation between TSI and any of the baseline parameters or between TSI and TBII at any timepoint. In conclusion, we found that the addition of T4 to methimazole does not result in a greater decrease in TSH receptor antibody concentrations than treatment with methimazole alone. From these results, we would predict no difference in remission rates among these patients, but confirmation of this prediction will need to await long-term follow-up of these subjects.

Adolescent↗
PubMed1993

Androsterone sulfate: physiology and clinical significance in hirsute women.

Androsterone sulfate (Andros-S) is the most abundant 5 alpha-reduced androgen metabolite in serum. To determine whether this steroid could serve as a marker of 5 alpha-reductase activity, we developed a specific RIA, using tritiated Andros-S to assess procedural losses. Baseline serum Andros-S levels (mumol/L; mean +/- SEM) in 14 hirsute women (3.0 +/- 0.4) were not reduced by ovarian suppression with leuprolide (3.0 +/- 0.3), but were decreased by 79% with combined ovarian and adrenal suppression with leuprolide and dexamethasone. The mean Andros-S level in polycystic ovarian syndrome (3.2 +/- 0.4) and in idiopathic hirsutism (3.5 +/- 0.5) was not significantly different from levels in normal women (3.0 +/- 0.5), but were significantly greater than levels in obese women (1.7 +/- 0.3; P < 0.05). The serum concentrations of Andros-S were about 10-fold greater than those of androsterone glucuronide and 100-fold greater than those of androstanediol glucuronide. Serum Andros-S concentrations correlated strongly with dehydroepiandrosterone sulfate (R = 0.59; P < 0.001) and to a lesser degree with androstanediol glucuronide and androsterone glucuronide (R = 0.28 and 0.49, respectively). There was a weak correlation with androstenedione levels and the androstenedione response to ACTH (R = 0.38 and 0.34, respectively), and no significant correlation with serum testosterone (R = 0.19). The ratio of any of the 5 alpha-reduced products (Andros-S, androstanediol glucuronide, and androsterone glucuronide) to precursors (androstenedione and testosterone) was not increased in hirsute women, suggesting that these women did not have a generalized increase in 5 alpha-reductase activity. In conclusion, these results confirm that Andros-S is the most abundant 5 alpha-reduced androgen metabolite in serum. It is primarily, if not exclusively, of adrenal origin in hirsute women. The fact that its levels were not elevated in hirsutism, although those of other adrenal androgens and androgen metabolites (androstanediol glucuronide and androsterone glucuronide) were, suggests that variations in sulfotransferase activity or metabolic clearance of Andros-S may be important determinants of serum Andros-S levels. Although Andros-S may be a marker of systemic 5 alpha-reductase activity, there was no evidence of a generalized increase in 5 alpha-reductase activity in hirsute women. Andros-S is therefore not recommended as a marker of either adrenal androgen production or of hirsutism.

17-alpha-Hydroxyprogesterone↗
PubMed1993

Androstanediol glucuronide production in human liver, prostate, and skin. Evidence for the importance of the liver in 5 alpha-reduced androgen metabolism.

Androstanediol glucuronide (Adiol G) has been reported to be a marker of peripheral androgen metabolism and action. It consists of two isomers, Adiol 3-G and Adiol 17-G. Adiol G is formed from unconjugated precursors by the enzyme glucuronyl transferase. To determine the likely source of Adiol G formation in man, we developed a glucuronyl transferase assay and measured the activity of this enzyme in human liver, abdominal and scalp skin, and prostate. In human liver, glucuronyl transferase activity was linear with respect to time (up to 120 min) and tissue concentration (up to 1 mg/ml). Apparent Michaelis-Menten constant Km (micromolar) and maximum velocity (Vmax) (picomoles per mg/30 min) were 5.6 and 140 for dihydrotestosterone, 8.9 and 1300 for androstanediol, and 3.1 and 46 for androsterone, respectively. Conversion of androstanediol to Adiol G (/0.5 mg tissue.30 min) was 5.8-13.2%. Over 80% of the Adiol G formed in human liver was Adiol 17-G, similar to what has been previously found in human serum. Glucuronyl transferase activity was present at low levels in human prostate (conversion of androstanediol to Adiol G was 0.04-4.6%/50 mg tissue.120 min). Analogous conversion rates (/50 mg tissue.120 min) for human scalp skin were 0.2-0.4% and for human abdominal skin were 0.07-0.14%. Although dihydrotestosterone may be converted to androstanediol in peripheral tissues such as skin and prostate, our results suggest that the principal site of androgen conjugation to glucuronic acid is the liver. The present results cast doubt upon the role of androstanediol glucuronide as a specific marker of cutaneous androgen metabolism.

Adult↗
PubMed1992

Effect of finasteride, a 5 alpha-reductase inhibitor, on serum gonadotropins in normal men.

Testosterone exerts negative feedback control on gonadotropin secretion either directly, after aromatization to estradiol, or after 5 alpha-reduction to dihydrotestosterone (DHT). Conflicting data exist as to the role of DHT in the modulation of this negative feedback. To determine whether suppression of endogenous DHT alters gonadotropin secretion, we gave the selective 5 alpha-reductase inhibitor finasteride (5 mg daily), or placebo, to 20 healthy men for 28 days. Basal and GnRH-stimulated LH, bioactive LH, FSH, testosterone, and DHT levels were measured before and after 14 and 28 days of treatment. Basal DHT fell from 1.1 +/- 0.2 to 0.15 +/- 0.04 nmol/L after 28 days of finasteride treatment. A significant rise in baseline testosterone from 17.6 +/- 2.0 to 18.3 +/- 2.3 nmol/L was seen at 14 days (P = 0.046), but not at 28 days. No significant changes were seen in either basal or GnRH-stimulated gonadotropin levels on any day. We conclude that suppression of serum DHT levels with 5 mg finasteride daily in healthy young men has no discernible effect on serum gonadotropin levels.

Adult↗
PubMed1984

[A new concept for detailed measuring of the excretory function of the kidney].

A new method to investigate renal function in detail without use of catheters is demonstrated. This method combines the advantages of two techniques, the physiological clearance measurement technique and the isotope nephrogram technique. The function of each kidney is quantitated in terms of the velocity of renal blood flow, the velocity of filtration and secretion and the velocity of urine flow to the bladder. The new concept is illustrated by two clinical examples.

Female↗
PubMed1983

[Direct and non-invasive determination of cardiac volume].

An improved isotope method for direct and non-invasive determination of heart volume, ejection volume and volume/time is described. By taking account of the reduction in the radio-active marker during the procedure, very good correlation of the results with those of cine ventriculography carried out at the same time can be expected.

Cardiac Output↗
PubMed1981

[Results of computed tomography of the lumbar vertebral discs (author's transl)].

As shown in 150 patients, myelography and computed tomography (CT) lead to identical results in the investigation of vertebral disc lesions of the lower lumbar spine. In less severe disc changes, where myelography is not indicated, CT findings largely correspond with clinical findings. CT investigations are risk free, without side effects, painless, fast and economical.

Adolescent↗
PubMed1980

[The value of pretherapeutic lymphography in testicular teratoma and carcinoma of the bladder (author's transl)].

According to the results of our investigations pretherapeutic lymphography is of high clinical value in cases of testicular teratoma and carcinoma of the bladder. The exstirpation and subsequent histological evaluation of all retroperitoneal lymph nodes in 50 patients with testicular teratoma and carcinoma of the bladder revealed a diagnostic accuracy of 80% (n = 50). Thus, lymphography proves to be of major benefit for the planning of future treatment and the preoperative determination of the state of the disease.

Humans↗
PubMed1979

[The efficacy of chemotherapy in the treatment of cancer of the breast (author's transl)].

The article reports on two female patients with cancer of the breast who had primarily not been treated by surgery or exposure to radiation, but only with cytostatics. Complete remission of the tumour occurred in both patients in the course of several years of treatment. These two examples show that in patients with cancer of the breast in stages which appear refractory and hopeless, a treatment course with cytostatics should be attempted.

Antineoplastic Agents↗
PubMed1979

[The diagnostic value of lymphography in invasive carcinoma of the cervix stage 1B (author's transl)].

In invasive carcinoma of the cervix stage 1B our investigations showed 19% lymph node metastases (n = 47) which were verified by operation and microscopic examination. In all of these patients no lympographic evidence of metastases was observed. The value of lymphography in stage 1B invasive carcinoma of the cervix is limited. Since we found 19% false negative results and 0% false positive results, the operation of invasive carcinoma stage 1B of the cervix should therefore include a lympadenectomy which is not dependent on the results of lympography.

Female↗
PubMed1979

[Differential diagnosis of contrast medium recesses of the renal pelvis or the renal calyx system (author's transl)].

Contrast medium recesses in the renal pelvis and calyx system of a retrograde pyelogram or urogram are due to many widely different pathologico-anatomical changes in the renal region. It is the aim of the present study to show up this multitude of differential diagnostic possibilities which lead to contrast medium recesses in the renal pelvis and renal calyx system of a pyelogram.

Contrast Media↗
PubMed1978

[The differential projection index as a sign of metastases in lymph nodes (author's transl)].

Five hundred and fourty-four lymph nodes seen in 107 lymphograms were examined at operation and histologically. According to our findings the differential projection index (Px) of Wiljasalo has a high degree of accuracy. The index is calculated from the maximal (a) and minimal (b) diameter of the node in various projections, expressed as a percentage formula: see text. Even considering technical sources of error, such as varying degrees of magnification of lymph nodes on oblique projections, the accuracy of the index is very high at 80%. It can be considered as the most accurate sign of metastases during lymphography.

Humans↗
PubMed1977

[The diagnosis of cystic degeneration of the adventitia (author's transl)].

The clinical picture of cystic degeneration of the adventitia is illustrated by two cases. This usually occurs in a portion of an artery near a joint, most commonly in the popliteal artery. The diagnosis is made in the presence of irregular, intermittent claudication associated with an "hour glass" stenosis of the popliteal artery on the arteriogram, without displacement of the vessel. The aetiology is probably related to herniation of the synovia from the adjacent joint capsule; this explains not only the variable pressure within the cyst in the arterial wall, but also the connection found at operation between the adventitial cyst in the popliteal artery and the joint capsule. Treatment consists in shelling out of the cyst. The prognosis is good and recurrences do not occur.

Arterial Occlusive Diseases↗
PubMed1977

[Consideration of inhomogeneities in irradiation planning. 2. Influence of inhomogeneities on the shape of the depth dose curve in water with 42 MeV X-rays (author's transl)].

With 42 MeV high-energy radiation, inhomogeneities such as bones, fat, plaster or palacos have no particular influence upon the depth dose curve in water because of the relatively insignificant differences of their atomic numbers, and there is no need to consider them in calculation of the focal dose. Metallic inhomogeneities, however, their effective atomic numbers being relatively high, show a different behaviour in 42 MeV X-ray bremsstrahlung: Just behing the metallic inhomogeneity an increase of the dose as compared to water is to be seen (e.g. directly behind a metallic plate, 4.5 mm thick, the augmentation of the dose amounts to 17%). This difference between 42 MeV X-ray bremsstrahlung and 60Co gamma rays (see part I of the present study) in the shape of the depth dose curve following permeation of metal by the radiations is due to enhanced pair formation within the high-energy radiation of 42 MeV photons.

Adipose Tissue↗
PubMed1977

[Consideration of inhomogeneities in irradiation planning. 3. Influence of inhomogeneities on the shape of the depth dose curve in water with electronic radiation of different energies (author's transl)].

For electron beams the shift of the depth dose curve in water produced by an inhomogeneity with density rho2 and thickness d is to be calculated from Vcalc-d(rho1 -1). Because of additional energy losses by bremsstrahl production, this calculable value Vcalc has to be corrected by means of a factor K to be found experimentally. In the case of larger atomic numbers (metallic plate), and most intensely in the lower energy range from 10 to 20 MeV the loss of dosage on account of inhomogeneities is particularly high due to elastic scattering of electrons (e.g. 86% by a 4.5 mm metallic plate with 10 MeV electronic radiation).

Adipose Tissue↗