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Biomedical subjects

T Weber

Publications and source records attributed to T Weber.

At least 19 recordsLinked to original sources

Elevated HbA1 due to foetal haemoglobinaemia in children. A common artifact of certain ion-exchange chromatography methods.

Foetal haemoglobin (HbF) is known to elute with glycosylated haemoglobins (HbA1) in mini-column ion-exchange chromatography, thus producing falsely elevated values for HbA1 in subjects with foetal haemoglobinaemia. We studied the occurrence of this methodological artifact in 266 patients with suspected or known insulin-dependent diabetes mellitus (IDDM) and in 205 healthy children of various age groups. HbA1 was measured using ion-exchange chromatography with prefabricated mini-columns and HbA1c and HbF by high-performance liquid chromatography (HPLC). In healthy children of over 5 years of age, the HbA1 values were usually within the reference limits for adults. However, 69% of the children younger than 1 year of age and 7% of those 1-5 years of age had HbA1 levels above 10%. Their HbA1c values were normal but the HbF values were high. Six of the 223 patients with IDDM (2.7%) and three of the 43 patients with stress glucosuria (7%) had much higher HbA1 than HbA1c values. The discrepancy was again related to the presence of raised concentrations of HbF. We conclude that foetal haemoglobinaemia is more prevalent than was previously known, especially among children younger than 5 years of age. Presence of HbF will bias the use of HbA1 as a diagnostic aid or as an index of metabolic control in children with IDDM. Methods specific for HbA1c, such as HPLC, should be used in paediatric patients.

Adolescent

[Therapy of Amanita phalloides poisoning. Results of clinical and experimental studies].

On the basis of experimental and clinical results evidence accumulates that supportive therapy is still the milestone in the therapy of death cap poisoning. Today the letality is 20%. The main cause of the intoxication are the amatoxines which inhibit DNA dependent RNA Polymerase II or B. Parts of the supportive therapy are: diuresis with 150--200 ml urin/hour, careful corrections of disturbances in electrolyte and acid-base-metabolism, oral administration of charcoal and oral gut sterilization. In spite of a multitude of experimental and clinical reports on the effectivity of Penicillin G, thiocticacid and steroids there are no controlled studies to demonstrate the advantage of one regimen over the other. The time course of resorption and excretion of amatoxines clearly shows that hemoperfusion and/or hemodialysis are only of value if applied within the first 24 hours after poisoning. At this time neither anamnestic nor biochemical data give any clues to the probable course of the disease. Heterologous baboon liver perfusion may be lifesaving in coma hepaticum grade IV, but the small amount of cases so far does not yet allow any comments on its effectivity.

Amanita

Continuous measurement of transcutaneous fetal oxygen tension during labour.

Transcutaneous scalp oxygen tension (tcPO2) was measured during labour in 40 fetuses, using a modified Clark electrode (Radiometer, Copenhagen). In 24 of the fetuses the recordings were of good quality during the second stage of labour. After delivery the acid-base status and oxygenation of the umbilical cord blood was measured. A correlation was found between the tcPO2 and umbilical artery oxygen saturation (r = 0.56, p less than 0.01) and umbilical artery PO2 (r = 0.56, p less than 0.01). Furuthermore, a positive correlation was found between the area beneath the recorded tcPO2 curve during the last 10 minutes and the umbilical artery pH (r = 0.50, p less than 0.05). The data suggest that continuous transcutaneous PO2 measurement may be of value in monitoring high risk patients during labour.

Electrodes

Normal values for fetal scalp tissue pH during labour.

Normal values for fetal scalp tissue pH during labour were determined by using a glass electrode (Kontron-Roche). A total of 132 recordings was obtained and 84 (64 per cent) were of good quality. After a good quality recording had been obtained, there were 64 infants with an Apgar score of 9 or 10 at one and five minutes after delivery. The 64 recordings showed pH values (Mean +/- 2SEM) of 7.38 +/- 0.12 six hours before delivery and 7.28 +/- 0.12 at the time of delivery. Between the 5th and 55th minutes of the second stage of labour the pH (Mean +/- 2SEM) fell from 7.30 +/- 0.14 to 7.20 +/- 0.13.

Female

Pregnancy complications following conization of the uterine cervix (I).

The literature on the course of pregnancies following conization of the uterine cervix has been studied. It is demonstrated that an evaluation of the possible effect of conization upon subsequent pregnancy should be based upon a comparison of either pregnancies before and after conization or upon a comparison between pregnancies in women with a previous conization and in a control group of women without conization. In both cases the possible influence of conization can be evaluated only if the patient material is described as regards age, parity, number of previous pregnancies, smoking habits, etc., factors which may all influence the course of pregnancy. None of the previous publications have described the patient material sufficiently, and most studies have not tried to set up control groups. Due to these deficiencies we do not find it justified that conization leads to reduced fertility, increased frequency of spontaneous abortion, nor to increased perinatal mortality. An increased prematurity rate may not be rejected, however, but this point has not been adequately evaluated in the previous papers.

Abortion, Induced

Pregnancy complications following conization of the uterine cervix (II).

The effect of conization upon the course of pregnancy and the fertility has been evaluated. 44 women had a total of 66 pregnancies following conization. These 44 women were compared with an age-matched group of non-conized women, as well as with a group of non-conized women matched for both age and parity. There were more smokers among conized than among non-conized women. All other descriptive variables were found to be without significant differences between the groups compared. There was no significant difference in the frequency of spontaneous and induced abortion, prematurity or cesarean section between conized and non-conized women. The second stage of labor was found to be protracted in conized women. Fertility judged by the "latent period"--the time elapsed from the couple started sexual intercourse without use of contraception to the present pregnancy--showed no difference between conized and non-conized women. We conclude that although a greater number of patients is necessary to permit definite conclusions concerning the risk of pregnancy and delivery complications in conized women, it is of special interest that the present study did not demonstrate an increased risk of spontaneous abortion nor of prematurity.

Abortion, Spontaneous

Improved lysozyme assay in biological fluids.

We describe a simple, rapid, sensitive, and highly reproducible assay for lysozyme, with use of concentrated cell suspensions of Micrococcus lysodeikticus in Tris-buffered glycerol/water (40/60 by vol), pH 7.5. Stored at -20 degrees C, the cells' susceptibility to lysozyme remains unaltered over long periods. Almost identical concentration curves were obtained with different aliquots of the same preparation during eight months. Lysozyme activity was reflected in the decrease in absorbance of the reaction mixture after incubation for 15 min at 37 degrees C. Concentrations of egg-white lysozyme as low as 0.02 mg/L can be accurately assayed.

Biological Assay

[Gonadotropin secretion following pernasal stimulation with synthetic gonadotropin releasing hormone (GnRH) and a highly effective GnRH-analog in healthy men and prepubertal boys].

Potent long acting analogs of GnRH are of great interest especially in view of pernasal (p.n.) treatmen of hypogonadism of hypothalamic origin and of cryptorchidism. To find the necessary p.n. dosage of such a substance, serum LH and FSH were measured in 6 normal adult human males after p.n. application of various doses of D Leu6-des-Gly10-GnRH ethylamide. 50 microgram of the GnRH analog were necessary to obtain increased serum gonadotropins over a period of at least 8 hours. By repeated p.n. application of 200 microgram of synthetic GnRH every 2 hours in 6 normal adult males a considerable increase of serum gonadotropins could be demonstrated as well. Pernasal application of 200 microgram GnRH repeated at an interval of 1 hour in 3 cryptorchid boys produced a distinct increase of the serum gonadotropins. The intraindividual comparison of 200 microgram GnRH and 20 microgram of the GnRH analog in one boy showed equivalent net increases of the gonadotropins. With the analog the gonadotropin increase lasted for about 6 hours.

Administration, Intranasal

Analysis of sixty consecutive cases of continuous fetal pH measurement.

60 consecutive fetal CTG-pH-registrations (cardiotocography with continuous pH registration) were analyzed in order to find the causes of the nonsuccessful tracings. Of the 60 tracings, 21 were of good quality, 16 partly successful, and 23 nonsuccessful. The monitoring for each patient had lasted for an average of 154 min with the range of 5--530 min. The quality of the pH recordings were not related to the duration of the pH observation, the maternal age and parity, or to the weight of the infant. If the electrode was applied too early (cervical orifice less than 5 cm) there was a greater risk of a nonsuccessful tracing. The drift of the electrode was less than 0.06 pH-units in 90% of the cases. The rate of nonsuccessful tracings is still too high and the difficulty in sterilization, calibration, and application of the electrode is still rather pronounced. At this moment the pH-electrode should be reserved for scientific use.

Electrodes

[Gonadotropin secretion after stimulation with a highly effective analog of the gonadotropin-releasing-hormone (GnRH) in normal adult human males (author's transl)].

Potent long acting anologs of GnRH are of great interest especially in view of treatment of hypothalamic hypogonadotropic hypogonadism and of cryptorchidism. To find necessary parenteral doses of such a substance immunoreactive serum LH and FSH were measured in 4 normal adult human males after s.c. injection of various doses of D-Leu6-des-Gly10-GnRH-EA. 5 microgram of the GnRH anlog were necessary to obtain increased serum gonadotropins over a period of at least 8 h. Comparable maximal levels were seen after i.v. bolus injection of 25 microgram natural GnRH a dose as used in diagnostic routine tests in 3 probands. Comparing the areas under the curves of LH secretion an over 15 times greater effectiveness of the analog was calculated.

Adult

Treatment of cryptorchidism with a potent analog of gonadotropin-releasing hormone.

Pernasal therapy of cryptorchidism with D-Leu6-des-Gly10-gonadotropin-releasing hormone ethylamide (D-Leu6-des-Gly10-GnRH-EA), a potent, long-acting GnRH analog, was attempted. Eleven prepubertal cryptorchid boys received between 25 microgram once daily and 25 to 50 microgram twice daily for 5 to 12 weeks. Complete testicular descent was achieved in 4 of the 11 boys. GnRH tests (1.5 microgram/kg intravenously), conducted in six boys before treatment, after 4 weeks of treatment, and in 2 boys 3 months after treatment, did not reveal changes in gonadotropin secretion indicative of precocious puberty or of decreased hypophyseal sensitivity to GnRH. Antibodies to the GnRH analog or to GnRH could not be detected.

Antibody Formation

Gonadotropin and testosterone secretion in normal human males after stimulation with gonadotropin-releasing hormone (GnRH) or potent GnRH analogs using different modes of application.

Gonadotropin-releasing hormone (GnRH) and some potent long-acting GnRH analogs, applied by different routes of administration, were tested in six healthy human males. The effects on gonadotropin secretion were compared with the one after intravenous (i.v.) bolus injection of 25 microgram of GnRH. The net increase of luteinizing hormone (deltaLH) in serum produced by 25 microgram of GnRH i.v. was matched by subcutaneous (s.c.) injection of 100 microgram of GnRH, dissolved in 20% gelatin or without gelatin; 5 microgram of D-Ser (TBU)6-des-Gly10-GnRH-ethylamide i.v.; 5 microgram of D-Leu6-des-Gly10-GnRH-ethylamide i.v.; and 50 microgram of D-Trp6-des Gly10-GnRH-ethylamide given pernasally (p.n.). D-Leu6-des-Gly10-GnRH-ethylamide, 50 microgram p.n., produced one-half such increase as did also multiple p.n. administrations of 200 microgram of GnRH every 2 hours. With 100 microgram of GnRH and all analogs, elevation of serum LH lasted for about 7 to 9 hours. The longest elevation was observed with GnRH dissolved in gelatin and with D-Ser (TBU)6-des-Gly10-GnRH-ethylamide, as reflected by the greatest areas under the curves of net increase. The longer the duration of the action of LH secretion, the higher was the observed increase in follicle-stimulating hormone (FSH). Correlation between effect on LH secretion and testosterone secretion was not found. By infusion of 1 microgram/kg/hour od D-Leu6-des-Gly10-GnRH-Ethylamide in two men over a period of 15 hours, a plateau of gonadotropin levels was reached within 7 to 9 hours. These plateau levels, especially of FSH, were higher than after bolus injection or p.n. application.

Administration, Intranasal