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Biomedical subjects

F Schmidt

Publications and source records attributed to F Schmidt.

At least 181 records · Page 10Linked to original sources
PubMed1982

The effect of levonorgestrel and estrone rods on male reproductive function.

The effect on spermatogenesis of the implantation of six rods containing levonorgestrel and three estrone rods was studied in seven volunteers aged 32-40, with normal pre-treatment spermiogram. None of the subjects achieved azoospermia. The lowest sperm count was below 1 million/ml in three subjects and below 12 million/ml in the other four. Plasma FSH and testosterone were severely depressed during the study, but LH was only transiently depressed for the first two months. Four subjects recovered pre-treatment sperm counts in spite of the FSH levels below 1.5 mIU/ml and testosterone levels below 1 ng/ml, which is contradictory to the current concept on hormonal regulation of spermatogenesis.

Adult↗
PubMed1982

Copper loss from the copper T model TCu22OC.

The effect of mineral deposits on the copper dissolution rate of the Copper T Model TCu22OC was examined. 118 Copper T22OC devices removed from subjects for various medical and personal reasons after 12 to 72 months in utero were examined and graded based on the proportion of the total copper area covered with mineral deposits. The deposits increased in average size during the first three years of IUD use and then remained relatively constant. Seventeen percent of the devices were in situ for four or more years. Copper analysis was performed on 30 Copper T 22OC devices from selected periods of use : 12-14, 22-26, 36-39 and 48-72 months of use. The mean daily copper loss was 29.4 micrograms and the range, 7.3 to 62.1 micrograms. An inverse correlation between the amount of mineral deposit on the copper surface and the rate of copper loss was observed.

Copper↗
PubMed1981

Comparative rheology of nucleated and non-nucleated red blood cells. I. Microrheology of avian erythrocytes during capillary flow.

Deformation and dynamic flow behaviour of nucleated duck erythrocytes were compared to those of nonnucleated human cells during steady flow (at wall shear stresses up to 3 N.m-2) through glass capillaries (diameter between 5 micrometer and 12 micrometer). While the deformation process of both cell species is qualitatively similar, significant quantitative differences demonstrate a lower deformability of the nucleated erythrocytes. In comparison to human cells, the avian red cells exhibit significantly lower stability of orientation during capillary flow. Viscometric measurements show that, in contrast to human red cell suspensions, the relative viscosity of nucleated cell suspensions does not decrease with increasing suspending medium viscosity. The results indicate that the hydrodynamic disturbance caused by avian erythrocytes in the flow of the suspending fluid is more pronounced than that of the mammalian cells. This is due to their lower ability to adapt to local shear forces.

Animals↗
PubMed1981

Comparative rheology of nucleated and non-nucleated red blood cells. II. Rheological properties of avian red cells suspensions in narrow capillaries.

The flow properties of nucleated avian (duck) red cell suspensions were determined in narrow glass capillaries (internal diameter 5- 11 micrometer) perfused at constant pressure. Measurements were carried out of cellular and suspending fluid flow velocity of dynamic (tube) hematocrit. Comparison with previous measurements on human erythrocyte suspensions showed that the dynamic hematocrit reduction (Fahraeus effect) of avian cell suspensions was significantly more sensitive to changes of hematocrit than observed on the human cells. It was in addition found that the Fahraeus effect is the dominating phenomenon determining the viscosity of the nucleated cell suspensions, in contrast to suspensions of non-nucleated human red cells. Furthermore, the apparent viscosity of the nucleated cell suspensions is significantly higher than that of human blood at equal capillary diameter and tube hematocrit. In the living capillary bed of birds, the unfavourable rheological properties of the nucleated red cells could be compensated for by a low capillary hematocrit and/or a higher capillary density compared to mammalian species.

Animals↗
PubMed1981

Sperm suppression with monthly injections of medroxyprogesterone acetate combined with testosterone enanthate at a high dose (500 mg).

The combination of an initial injection of 1000 mg of depot medroxyprogesterone acetate and 500 mg of testosterone enanthate, followed by monthly administration of 150 mg and 500 mg of the same drugs, was tested in 10 healthy males aged 28 through 39, with pre-treatment sperm counts of 50 x 10(6)/ml or more. Eight of the subjects achieved azoospermia, and the sperm counts of the other two declined 0.09 ad 5 million/ml. This last subject was highly refractory to treatment as his sperm density recovered to 27 million sperm/ml at the 6th month of continuous therapy. FSH was severely depressed during the entire treatment period. LH fell to 30--40% of normal values in the first two months and then showed a slow recovery during maintenance treatment. Testosterone measured one month after each injection was between 10 and 30% of pre-treatment values. Three of the subjects had increased libido and potency, none had decreased sexual drive or potency. All subjects gained weight with the average gain being 6 kg. The increase in the dose of testosterone enanthate to 500 mg/ng did not improve the results as compared to previous trials using lower doses of TE.

Adult↗
PubMed1981

Molecular nature of a streptomycin and sulfonamide resistance plasmid (pBP1) prevalent in clinical Escherichia coli strains and integration of an ampicillin resistance transposon (TnA).

A small, nonconjugative plasmid, designated pBP1, was originally found in different fecal Escherichia coli serotypes isolated from a healthy proband. Of a total number of 130 hospital strains of E. coli subsequently studied, 8.5% yielded plasmid of the pBP1 type. This R plasmid specifies resistance to streptomycin (Sm) and sulfonamides (Su) and has a mass of 4.0 megadaltons. Inactivation of streptomycin is due to the aminoglycoside phosphotransferase APH-(3 "). A physical map was constructed by analysis with restriction endonucleases. Another small plasmid, pBP1-1, was isolated from one of the hospital strains and characterized as an enlarged pBP1 replicon containing an additional deoxyribonucleic acid sequence identified as a transposable element for ampicillin resistance (TnA). Plasmid pBP1-1 was cleaved by restriction enzymes for identification of the transposon sequence which codes for a TEM 1 beta-lactamase. The sequence organizations in the Sm Su plasmids RSF1010 and pBP1 were shown to be identical for regions specifying streptomycin and sulfonamide resistance, but different for the region containing the origin of replication and genes for replicative functions. Thus, RSF1010, which has been considered as the prototype of Sm Su plasmids, and pBP1, which is at least as frequent in clinical isolates as RSF1010, do not have a single common ancestor.

Ampicillin↗
PubMed1981

Subdermal implants of different steroidal compounds for treatment of endocrinological disorders.

Various types of steroid-containing implants were used in the treatment of benign prostatic hypertrophy, congestive prostatitis, and hypogonadism. 2 Silastic capsules, each containing 22-23 mg of ethinyl estradiol, were inserted subcutaneously in 5 men with benign prostatic hypertrophy. A decline in testosterone levels to less than 1 ng/ml was attained within 6 months following insertion. 6-8 Silastic capsules containing 21-23 mg each of testosterone were implanted in 15 men: 2 castrates and 13 hypogonadals. Testosterone levels increased initially, reaching the highest level at 3 months. Thereafter, the testosterone concentrations declined but remained slightly above pretreatment levels at 9 months. In a group of 9 subjects, 7 men with hypogonadism and 2 women with hypernephroma were treated with 2 rods, each containing approximately 200 mg testosterone propionate. Testosterone concentrations showed initial rises but did not remain elevated. 12 male subjects, 6 with congestive prostatis and 6 with benign prostatic hypertrophy, were treated with a combination of 3 levonorgestrel rods and 3 estrone rods. Each rod contained 40 mg of steroid. This regimen had a therapeutic effect but was only partially successful in inhibiting spermatogenesis.

Adult↗
PubMed1981

[Lymphography in testicular tumors].

In 45 patients with tumours of the testes (5 seminomas, 40 nonseminomas) the pretherapeutic lymphographic diagnosis could be histologically tested after a retroperitoneal removal of lymph nodes. The lymphographic security was more than 82%, 4 diagnoses each were falsely positive and falsely negative. The sensitivity was 81%, the specifity 83%. With these results the lymphography meets the requirements which are made upon a diagnostic method. It shall be relevant to therapy. An increase of the security by additional examinations (tomography and cavography) is possible. Taking into consideration its limits the bipedal lymphography belongs to the obligatory spread diagnosis in tumours of the testes, its results allow an estimation of the spread of the tumour, the therapeutic effect and the prognosis of the tumour disease.

Choriocarcinoma↗
PubMed1981

[Nuclear magnetic resonance tomography].

Imaging methods based on nuclear magnetic resonance allow the production of sectional images of the human body without ionizing radiation. It is possible to measure the density and relaxation times of the water protons in body fluids or tissue. This allows not only to obtain morphological information but also to get some insight into the spatial distribution of physiological data. Starting with a review of the principles of nuclear magnetic resonance it is explained how the measured signal can be associated with an image point; it is also explained what type of apparatus is necessary and what the physical limitations are. Possible risks the patient may be exposed to in an examination using nuclear magnetic resonance are discussed. The present state of the technical development enables the production of whole-body sectional images of a living person within about one minute. By means of some typical examples the nature and properties of these images are explained. Although extensive clinical studies will be necessary before a more general assessment can be made of this method, an outlook is provided on expected further developments and possible future fields of application.

Humans↗
PubMed1980

[Results obtained from staining lymphography, using carbon with lipoidal suspension, in cases of female genital carcinoma (author's transl)].

Reported in this paper is the use of a carbon-lipoidal suspension for presurgical staining lymphography which was applied to carcinomata colli uteri and corporis uteri. The suspension could not be prepared until permission had been obtained from the National Drug Expert Committee. Better colour contrast representation of the femoral and iliacal lymph nodes during the operation was thus achieved, and, consequently, surgical radicality was substantively improved. The approach proved less expensive and tedious than previous methods used for colour representation of lymph nodes in the minor pelvis. The dye used did not cause any complications. The advantages of the method are discussed. General application seems to be commendable, following further testing.

Carbon↗
PubMed1980

Elevated plasma and urinary guanosine 3':5'-monophosphate and increased production rate in patients with neoplastic diseases.

The plasma and 24-hr urinary levels of cyclic adenosine 3':5'-monophosphate and of cyclic guanosine 3':5'-monophosphate (cGMP) were determined for 19 healthy normal patients, 54 patients with six types of nonneoplastic diseases (cholelithiasis, peptic ulcer, coronary heart disease, hypertension, regional ileitis, and cirrhosis), and 54 patients with five types of neoplastic disease (cancers of the lung, colon, and breast, acute myelocyte leukemia, and Hodgkin's disease). The cyclic adenosine 3':5'-monophosphate levels of urine and plasma in normal subjects, in noncancer subjects, and in cancer subjects did not differ significantly. The cGMP levels in the noncancer group were similarly unchanged from those in the normal group. However, mean cGMP levels in the urine and plasma of patients with neoplastic diseases were, respectively, 2- and 3-fold greater than the normal values (p less than 0.005 for urine and p less than 0.05 for plasma). Pharmacokinetic studies with [3H]cGMP in nine healthy controls and 15 patients with neoplasia showed that the mean production rate of this nucleotide in patients with metastatic cancer was elevated when compared to normal patients, but many values fell within the normal range. In acute leukemia, the production rate was seven times normal, with four of five patients having values clearly outside the normal range. The plasma clearance rate in patients with neoplasia was not decreased when compared to that in normal patients. It is proposed that an increased production rate, rather than any change in plasma clearance, accounts for the increased levels of cGMP in the plasma and urine of some patients with neoplastic disease.

Cyclic AMP↗