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Biomedical subjects

W Seitz

Publications and source records attributed to W Seitz.

At least 55 records · Page 3Linked to original sources
PubMed1987

Photoaffinity labelling of the phenylalkylamine receptor of the skeletal muscle transverse-tubule calcium channel.

The tritiated arylazido phenylalkylamine (-)-5-[(3-azidophenethyl)[N-methyl-3H]methylamino]-2-(3,4, 5-trimethoxyphenyl)-2-isopropylvaleronitrile was synthesized and used to photoaffinity label the phenylalkylamine receptor of the membrane-bound and purified calcium channel from guinea-pig skeletal muscle transverse-tubule membranes. The photoaffinity ligand binds reversibly to partially purified membranes with a Kd of 2.0 +/- 0.5 nM and a Bmax of 17.0 +/- 0.9 pmol/mg protein. Binding is stereospecifically regulated by all three classes of organic calcium channel drugs. A 155 kDa band was specifically photolabelled in transverse-tubule particulate and purified calcium channel preparations after ultraviolet irradiation. Additional minor labelled polypeptides (92, 60 and 33 kDa) were only observed in membranes. The heterogeneous 155 kDa region of the purified channel was resolved into two distinct silver-stained polypeptides after reduction (i.e. 155 and 135 kDa). Only the 155 kDa polypeptide carries the photoaffinity label and it is concluded that the 135 kDa polypeptide (which migrates as a 165 kDa band under alkylating conditions) is not a high-affinity drug receptor carrying subunit of the skeletal muscle transverse-tubule L-type calcium channel.

Affinity Labels↗
PubMed1987

Technique of ruthenium-106 application in the treatment of conjunctival melanoma.

In 1966 Lommatzsch has introduced the ruthenium-106 radiation therapy in the treatment of the choroidal melanoma. He reported on good results with a less rate of ocular side effects in compare to the different forms of conventional radiation therapy modalities. It seemed useful to utilize the advantages of ruthenium-106 therapy also for the treatment of the conjunctival melanoma. The technique of the ruthenium-106 irradiation of conjunctival melanoma is described and the first clinical results are reported.

Aged↗
PubMed1986

Aortic valve orifice equation independent of valvular flow intervals: application to aortic valve area computation in aortic stenosis and comparison with the Gorlin formula.

An orifice equation is derived relating the effective aortic valve area, A, the average aortic valve pressure gradient, dP, the stroke volume, SV, and the heart frequency, FH, through considerations of momentum conservation across the aortic valve. This leads to a formula consistent with Newton's second law of motion. The form of the new equation is A = (7.5 X 10(-5)) SV FH2/Pd, where A, VS, FH and Pd are expressed in cm2, ml, s-1 and mmHg, respectively. Aortic valve areas computed with the new orifice equation are found to correlate with those computed by the Gorlin formula in conditions of resting haemodynamic states at a level of r = 0.86, SE = 0.25 cm2, N = 120. The results suggest that the new formula may be considered as an independent orifice equation having a similar domain of validity as the Gorlin formula. The new equation offers the possibility of deriving additional useful haemodynamic relationships through combination with established cardiological formulas and applying it in a noninvasive Doppler ultrasonic or echocardiographic context.

Aged↗
PubMed1986

A comparison of two types of anaesthesia on the endocrine and metabolic responses to anaesthesia and surgery.

The influence of halothane-nitrous oxide anaesthesia and normotensive epidural analgesia (level of sensory block T8-T10), respectively, on the plasma concentrations of adrenocorticotrophic hormone (ACTH), beta-lipotropin (beta-LPH), cortisol, dehydroepiandrosterone (DHA) and aldosterone as well as on the metabolites glucose, lactate and free fatty acids (FFA) was studied in 20 healthy patients who underwent elective orthopaedic procedures on the lower limbs. ACTH and beta-LPH concentrations in plasma rose significantly (P less than 0.001) during halothane-nitrous oxide anaesthesia. DHA secretion closely followed the secretory profile of cortisol. Increased renin levels and increased ACTH release seemed to be responsible for increased aldosterone secretion, intra-operatively. The hormonally induced rise of glycogenolysis and lipolysis did not produce important intra-operative increases in metabolite concentrations in the blood. In normotensive epidural analgesia no significant increase in stress response could be demonstrated, even with low levels of sensory block.

Adrenocorticotropic Hormone↗
PubMed1986

Thyroid status during pregnancy and post partum in regions of iodine deficiency and endemic goiter.

During pregnancy the thyroid is subjected to increased demands which is associated with a tendency to endogenous iodine deficiency. Under the conditions of insufficient iodine supply in the GDR the pathophysiological changes result in: 1. prevalence of goiter in about 60% of pregnant women; 2. enlargement of the extent of neck in more than 50% of all pregnant women examined only returning to the prepregnant status in 25%-40%; 3. prevalence of goiter in newborn with 5%; 12.8% of 1948 stilborn had macroscopically an enlarged thyroid gland, the highest weight being 45 g. More than 53% of the stilborn examined by autopsy had a thyroid weight of over 3 g; 4. in contrast to the regions with sufficient iodine supply renal iodine excretion was steadily decreasing during pregnancy and post partum, changing the iodine deficiency from grade II to grade III; 5. low iodine excretion in newborn: 1.3 +/- 0.2 microgram I/day in goitrous (1.2 +/- 0.2 nmol I/mmol creatinine) 2.2 +/- 0.4 micrograms I/day in non-goitrous (2.0 +/- 0.4 nmol I/mmol creatinine); 6. according to ETR more than 50% of the pregnant examined showed a hypothyroid tendency. The pathophysiological changes during pregnancy caused by insufficient iodine supply can be met efficiently by careful thyroid hormone treatment or by the administration of 150 micrograms I daily. A mandatory iodine salt prophylaxis is demanded.

Adolescent↗
PubMed1986

[Catheter peridural anesthesia with bupivacaine-HCl and bupivacaine-CO2 during extracorporeal shock-wave lithotripsy].

The effects of 0.5% bupivacaine-CO2 and bupivacaine-HCl were tested in a prospective randomised trial on 16 patients who underwent extracorporal shock wave lithotripsy (ESWL) with epidural analgesia. A shorter time of onset of analgesia (3.75 +/- 0.51 min) and a faster distribution of analgesia were noted with bupivacaine-CO2. Hypoalgesic regions were not registered with bupivacaine-CO2 nor with bupivacaine-HCl under shock wave treatment. About thirty minutes after application of either substance a level 1 block according to Bromage was noted, which was not desirable during positioning of the patient on the hydraulic lithotriptor chair. However, toxic blood levels were not reached in either group of patients to any extent.

Anesthesia, Epidural↗
PubMed1986

[Effect of nalbuphine on respiration].

The respiratory depressant effects of 0.25 mg/kg nalbuphine were analyzed in detail in seven healthy volunteers by determining the CO2 response (Read's method) and the mouth occlusion pressure (Whitelaw's method) before and 10, 30 and 60 min after administration of the drug. Minute ventilation VE (PACO2 = 55 mm Hg) decreased after nalbuphine by a maximum of 36.4% (P less than 0.05). Simultaneously, the slope of the right-shifted CO2 response curve was diminished by 21.1% (NS) while the mouth occlusion pressure decreased by 36.3% (P less than 0.05), respectively. There were only slight changes in mean inspiratory flow rate. These findings demonstrate that nalbuphine does not lead to relevant impairment of central respiratory regulation or respiratory mechanics.

Adult↗
PubMed1985

[Male breast cancer].

Between 1974 and 1982 inclusive 18 male patients were treated for breast carcinoma. 12 patients had postoperative radiotherapy whereas 4 were referred for treatment of recurrent or metastatic disease. One patient showed signs of inflammatory breast cancer and was treated with chemo-radiotherapy and one was being followed up in our department after radiotherapy for prostatic cancer in 1970. Median overall survival was 52 months and the median disease-free interval was 21 months.

Aged↗
PubMed1985

[Determination of creatinine in the urine as a reference value of substances excreted by the kidney].

The creatinine excretion is often used as reference value of renally excreted substances. It is usual to perform the creatinine determination according to the Jaffe method. However, since this reaction is influenced not only by the creatinine content but also by other substances it was for orientation tested to which extent adequate incorrect determinations may appear. For this purpose the creatinine content was determined in 28 casual urine specimens in the analysis automation (A) and manually (M) according to the Jaffe method as prescribed in the German Pharmacopoeia 7th ed. D. L. As comparison the enzymatic determination (E) was performed. The determinations according to Jaffe showed too high values. The mean relative percental deviation for the determination in the analysis automation was for (Formula: see text) (variation 6.7 to 94.3%). There were firm correlations between the values of the three determination methods. Since the creatinine determination after Jaffe is the cheapest and most practicable method, in clinical routine work in creatinine-related data of concentration of various renally excreted substances one should realize that in the individual case deviations of the concentration are possible on average up to 50%.

Creatinine↗
PubMed1985

[Behavior of the hypophyseal-adrenal cortex system in inhalation and conduction anesthesia. A review with comparative study].

The effects of halothane anaesthesia or epidural analgesia on the per- and postoperative change in blood concentrations of ACTH, beta-lipotropin, cortisol, dehydroepiandrosterone, aldosterone, glucose, lactate and free fatty acids were investigated in connection with elective orthopaedic surgery. Anaesthesia in man with halothane and nitrous oxide was found to be associated with a significant increase in plasma ACTH levels and beta-LPH levels. Changes in plasma dehydroepiandrosterone were similar to those in plasma cortisol. The elevation of plasma aldosterone during major surgery could be explained as the effect of an increased renin secretion. However, simultaneous increase in plasma cortisol and plasma aldosterone during surgery reflect an additional effect of adrenocorticotropin upon aldosterone secretion.

Adrenal Cortex↗
PubMed1985

[Suppression of the adrenal cortex by infusion of etomidate in general anesthesia].

The effects of anaesthesia with fentanyl and prolonged etomidate infusion (0.8 mg/kg/h) on the peroperative and postoperative change in blood concentrations of aldosterone, cortisol, dehydroepiandrosterone, ACTH, epinephrine, norepinephrine, dopamine, glucose, lactate and free fatty acids (FFA) were investigated in connection with major abdominal surgery. During surgery and anaesthesia with prolonged etomidate infusion no significant alterations in plasma catecholamine concentrations were observed. In contrast, basal plasma levels of ACTH (20.0 +/- 9.5 pg/ml----352.8 +/- 150.8 pg/ml) were elevated in all patients. Despite this endogenous ACTH stimulus, aldosterone (121.8 +/- 19.4 pg/ml----58.4 +/- 10.4 pg/ml) and cortisol (12.3 +/- 2.84 micrograms/dl----5.79 +/- 1.2 micrograms/dl) and dehydroepiandrosterone (2.28 +/- 1.09 ng/ml----1.27 +/- 0.25 ng/ml) levels were markedly depressed in every patient during the perioperative period. Twenty-four hours after surgery the basal steroid values were within or above normal limits.

Abdomen↗
PubMed1985

[Effect of tramadol on ventilatory CO2 response and mouth occlusion pressure].

The respiratory depressant effects of 1.0 and 1.5 mg/kg of tramadol were studied in 14 healthy young persons by determining the CO2 response (Read's method) and the mouth occlusion pressure (Whitelaw's method) before and 10, 30 and 60 min after administration of the drug. The decrease in minute volume VE (PACO2 = 55 mmHg), dependent on dose, ranged between 11,2 and 17,8%. The mean ventilatory response to CO2 decreased after administration of 1.0 and 1.5 mg/kg of tramadol by 15.4 and 25.4% respectively of the normal value. In the same patients, the mouth occlusion pressure responses decreased by 16.1 and 25.6% respectively. There were no significant changes in mean inspiratory flow rate (determined from tidal volume and averaged time of inspiration). These findings demonstrate that tramadol, in contrast to morphine, produces less depression of the ventilatory responses to CO2 in healthy subjects.

Adult↗
PubMed1985

[A clinical study of circulatory depression and pharmacokinetics following peridural anesthesia with bupivacaine 0.75%. Preoperative phase].

In previous study it was demonstrated that the clinical use of bupivacaine 0.75% for peridural anesthesia appears to be without risk. There was seen no toxicity (bradycardia, convulsion, respiratory depression etc) at the measured plasma levels. Very important is the early onset of action of this drug contrary to the other used concentrations. It is useful for a major surgery. Hypotension can be avoided by applying volume transfusion.

Anesthesia, Epidural↗
PubMed1985

[Cardiocirculatory effects of a new sympathomimetic, amezinium methyl sulfate. Results of human pharmacological studies].

Changes in haemodynamic, inotropic state, and myocardial oxygen consumption were investigated in a total of eight patients with coronary artery disease after intravenous injection of 0.07 mg/kg amezinium methyl sulfate (LU 1631, Supratonin). It was demonstrated, that the principal effects of amezinium are consistent with those of a sympathomimetic agent which stimulates vascular alpha- and beta 1-adrenoreceptors. Amezinium (0.07 mg/kg) increased cardiac index, mean arterial pressure and total systemic resistance and dp/dtmax, while there were only minor changes in stroke index, mean pulmonary pressure and total pulmonary vascular resistance. In accordance with the changes in haemodynamics there was a 21.5% increase in myocardial oxygen consumption. But there were no signs of imbalance between oxygen supply and oxygen demand.

Adult↗
PubMed1985

[Endocrine reaction pattern in abdominal surgical patients as affected by isoflurane anesthesia].

The effects of isoflurane anaesthesia on the per- and postoperative change in blood concentrations of aldosterone, cortisol, dehydroepiandrosterone, insulin, prolactin, thyroxine, t3-uptake, epinephrine, norepinephrine, dopamine, glucose, FFS, lactate, and pyruvate were investigated in connection with major abdominal surgery. Contrary to prolactin levels (8.42 +/- 1.71 ng/ml----46.25 +/- 6.78 ng/ml; p less than 0.001) the plasma concentrations of the adrenal steroids aldosterone, cortisol, and dehydroepiandrosterone sank initially after induction of anaesthesia with thiopentone. However, after skin incision the levels of aldosterone (49.9 +/- 11.6 pg/ml----202.1 +/- 57.6 pg/ml; p less than 0.01), cortisol (16.7 +/- 2.57 ng/dl----25.2 +/- 3.72 ng/dl; p less than 0.01) and DHEA (2.70 +/- 0.99 ng/ml----5.02 +/- 1.03 ng/ml; p less than 0.05) rose significantly. Generally, plasma insulin was not markedly influenced by isoflurane anaesthesia and surgery. No significant alterations in plasma catecholamine concentrations were observed.

Abdomen↗
PubMed1984

[Endocurie therapy of breast cancer I. Indication and value of the implantation of iridium 192 within the total concept of conservative organ-preserving therapy of breast cancer].

The goal of conservative surgery is reduction of macroscopic tumour masses and lymph node sampling. In combination with adequate radiotherapy the local control rates reported by some authors are as good as those of radical surgery. Interstitial implantation of Ir192 offers the possibility of applying very high radiation doses without early complications and late effects. This method could also be carried out effectively as primary treatment, even for locally advanced stages. The recurrence rates for early breast cancer in a few reports are lower than 10%. Combined with systemic therapy the treatment results even in T3 and T4 lesions are relatively satisfactory. These treatment concepts remain to be tested in controlled clinical trials.

Brachytherapy↗
PubMed1984

[Endocurie therapy of breast cancer II. Radiation biology problems].

The problem of combining fractionated MeV teleradiotherapy with protracted interstitial irradiation is discussed. Synchronization, reoxygenation, redistribution, regeneration and repair phenomena determine the biological consequences during protracted exposure. This is especially important in the treatment of macroscopic tumour masses.

Brachytherapy↗