Search PubMed⌕ Search

Biomedical subjects

W Schmidt

Publications and source records attributed to W Schmidt.

At least 433 records · Page 24Linked to original sources
PubMed1988

Response of the seminiferous epithelium to scattered radiation in seminoma patients.

Semen and blood samples were obtained, at 3-month intervals over 12 to 28 months, from patients who underwent subdiaphragmal radiation after orchidectomy for seminoma testis. Before radiotherapy a mean (+/- SE) semen volume of 4.7 +/- 0.5 ml, a mean sperm count of 44.4 +/- 13.5 x 10(6)/ml, a mean percentage of motile cells of 20.3 +/- 5.2, a mean percentage of morphologically normal spermatozoa of 13.4 +/- 5.4, a mean percentage of swollen sperm of 39.6 +/- 7.4, and a mean serum follicle-stimulating hormone (FSH) value of 8.3 +/- 1.2 mIU/ml was found. The mean testicular dose from scatter was 62 +/- 5 cGy (range, 34 to 95 cGy). Sperm counts between 0 and 2.75 x 10(6)/ml were seen at 6.8 +/- 0.6 months and recovery to values greater than 2.25 x 10(6)/ml at 11.8 +/- 0.8 months after the start of radiation. Peak FSH values of 19.2 +/- 1.6 mIU/ml were obtained at 6.7 +/- 0.9 months after the start of irradiation. After recovery mean semen volume was 3.9 +/- 0.4 ml, mean sperm count 34.6 +/- 5.6 x 10(6)/ml, the mean percentage of motile cells 42.5 +/- 6.0, the mean percentage of swollen sperm 58.7 +/- 6.8, and the mean percentage of spermatozoa with normal morphology 23.4 +/- 5.1. Only motility was significantly different (P less than 0.01) from pretreatment values. The elevation of FSH values with time after start of radiotherapy reflected the toxicity to spermatogenesis but no correlation was found between peak FSH levels and scattered radiation dose. Also, neither the time from start of radiotherapy to sperm count nadir or recovery nor the time to peak FSH levels was significantly correlated with radiation dose.

Adult↗
PubMed1988

Changes in the activity of gamma-glutamyl transpeptidase induced by kainic acid and surgical lesions of the hippocampal formation in young rats.

To study possible functional involvement of gamma-glutamyl transpeptidase (GGT) in glutamate transmitter metabolism we lesioned putative glutamatergic structures of the rat hippocampal formation by intracerebroventricular (i.c.v.) injection of kainic acid (KA) or by surgical CA3 axotomy. Unilateral injection of KA into the left lateral cerebral ventricle of 30-day-old rats resulted in decreased GGT activity in hippocampal areas CA3, Ca1 ipsilaterally, and in the contralateral area CA1, four hours after the induction of the chemical lesion. Four days after the injection, the enzyme activity was decreased in all hippocampal areas with the exception of the contralateral dentate gyrus. Four days after bilateral i.c.v. injection of KA, lower GGT levels were found than was seen after bilateral surgical lesion of the CA3 pyramidal cell axons (Schaffer's collaterals). The surgical lesion was followed by a decrease of GGT only in the stratum pyramidale and stratum radiatum of area CA1. In contrast to the effects in 30-day-old rats, unilateral i.c.v. injection of KA on postnatal day 12 did not alter the GGT activity in any studied hippocampal area presumably because of incomplete maturation of structures required for KA vulnerability.

Age Factors↗
PubMed1988

Hemoglobin oxygen affinity in patients suffering from arterial occlusive disease of the legs.

Parameters characterizing the hemoglobin oxygen affinity were determined in blood of 12 male patients suffering from arterial occlusive disease (AOD) of the legs and compared with data obtained earlier from healthy human subjects (controls). Due to a COHb content of 4.8% +/- 2.2% in the cigarette-smoking AOD patients, the standard oxygen dissociation curve (ODC) was left-shifted, the half-saturation pressure (P50) amounted to 24.8 +/- 1.7 mmHg (3.30 +/- 0.23 kPa), although the 2,3-diphosphoglycerate concentration was increased to 15.3 +/- 1.7 mumol/g Hb. Correcting the effects of elevated COHb shifts the P50 to 26.3 mmHg (3.5 kPa) and increases the steepness of the ODC (Hill's "n") from 2.79 +/- 0.27 to about 2.99, which is significantly different from controls. The Bohr coefficients after acidification of blood with lactic acid (BCLac) show high values at low oxygen saturations of hemoglobin (-0.50 +/- 0.04 in AOD patients, -0.32 +/- 0.04 in controls; P less than 0.05 at 10% SO2). The cause of the alterations in hemoglobin oxygen affinity may be a reduced mean erythrocyte age, but also the influence of unknown factors generated, e.g., from anaerobic muscle metabolism in AOD.

Arterial Occlusive Diseases↗
PubMed1988

5'-3' exonucleases in phosphorothioate-based oligonucleotide-directed mutagenesis.

The application of T7 and lambda exonuclease to phosphorothioate-based oligonucleotide-directed mutagenesis was investigated. Oligonucleotide primers designed to introduce single or double base mismatches, an insertion or a deletion (each of 16 bases) were annealed to M13 phage derivatives. Double stranded closed circular DNA (RF IV) containing phosphorothioate internucleotidic linkages in the (-)strand was prepared enzymatically from these templates. A nick was introduced into the (+)strand of the hetroduplex DNA. This nicked DNA (RF II) was subjected to treatment with T7 or lambda exonuclease. Both of these enzymes were able to degrade almost all of the viral (+)strand when presented with DNA containing one or two base mismatches. Repolymerisation of the DNA after the gapping reaction, followed by transfection into E. coli cells gave mutational efficiencies of up to 95%. In the case of RF II DNA prepared with insertion or deletion primers these exonucleases could only partially degrade the viral (+)strand but were nevertheless highly efficient in such mutagenesis experiments.

Base Composition↗
PubMed1988

Strand specific cleavage of phosphorothioate-containing DNA by reaction with restriction endonucleases in the presence of ethidium bromide.

A method for achieving strand specific nicking of DNA has been developed. Phosphorothioate groups were incorporated enzymatically into the (-)strand of M13 RF IV DNA. When such DNA is reacted with restriction endonucleases in the presence of ethidium bromide nicked DNA (RF II) is produced. All of the restriction enzymes tested linearised phosphorothioate-containing DNA in the absence of this dye. The strand specificity of the reaction was investigated by employing the ethidium bromide mediated nicking reaction in the phosphorothioate-based oligonucleotide-directed mutagenesis method. The mutational efficiencies obtained were in the region of 64-89%, indicating that these restriction enzymes hydrolyse the phosphodiester bond at the cleavage site of the unsubstituted (+)strand.

Base Composition↗
PubMed1988

High-affinity uptake of L-[3H]glutamate and D-[3H]aspartate during postnatal development of the hippocampal formation: a quantitative autoradiographic study.

Quantitative autoradiography was used to determine the topographical and time patterns of L-[3H]glutamate and D-[3H]aspartate high-affinity uptake system in the hippocampal formation of the rat during postnatal development. Extended control experiments were performed to verify the specificity of labelling. For short incubation periods of 3-10 min, the data demonstrated a conspicuously low rate of glutamate accumulation in the hippocampal formation of newborn animals and a marked increase in labelling of hippocampal neuropil areas during the first weeks of postnatal life. Our autoradiographic data on developmental increase in glutamate high-affinity uptake levels are consistent, in terms of time and topography, in many ways with other parameters of maturation of glutamatergic and/or aspartatergic structures in the hippocampal formation.

Animals↗
PubMed1988

Training induced effects on blood volume, erythrocyte turnover and haemoglobin oxygen binding properties.

The effect of three weeks ergometer training (Tr) 5 times a week for 45 min at 70% VO2max by 6 subjects on erythrocyte turnover and haemoglobin O2 affinity has been studied. Increased reticulocytosis could be observed from the second day after beginning Tr until a few days after its end, probably caused by increased erythropoietin release by the kidney. Erythrocyte destruction was most pronounced in the first and markedly reduced in the third week of Tr. Elevated glutamate oxalacetate transaminase activity and creatine as well as lowered mean corpuscular haemoglobin indicate a younger erythrocyte population in the first week of recovery. Total blood volume increased during the course of Tr by 700 ml, mainly caused by a raised plasma volume (74%). Red cell volume increased later with maximal values one week after Tr (+280 ml). In this week the standard oxygen dissociation curve was most shifted to the right (P50 increased from 3.77 +/- 0.05 kPa to 3.99 +/- 0.07 kPa) and the Bohr coefficients had their lowest values. Both effects are completely explainable by the haemoglobin O2 binding properties of young erythrocytes. After training, all parameters of physical performance (VO2max, maximal workload, heart rate during rest and exercise) were markedly improved, indicating fast adaptation mechanisms. The increased erythrocyte turnover, including higher erythropoiesis, seems to be one important part of these effects.

Adult↗
PubMed1988

[Ultrasonography in the primary diagnosis and follow up of ovarian tumors].

Preoperative sonographic data in 317 patients who underwent surgery at the University Women's Clinic Heidelberg for an ovarian tumour during a 6 years' observation period, were compared with the results of clinical examination. The prognostic value of both techniques was examined, by relating the findings (as to tumour size, demarcation from the uterus) to the postoperative histological or cytological diagnosis. In the 214 cases of benign and 103 of malignant ovarian tumours a correct diagnosis was provided by ultrasound in 88% and 74% respectively. Thus significantly more often than by clinical examination alone (p less than 0.001 for benign and p less than 0.01 for malignant tumours). The sonographic findings in 49 patients during follow-up after surgery for ovarian carcinoma and polychemotherapy were checked by a second look laparotomy. The detection rate of tumour progression, recurrence, residual tumour or remission was of 98%.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

[Doppler flow studies (duplex sonography). Differential diagnostic assessment of intrauterine growth retardation and uncertain gestational age].

In 116 patients referred to Heidelberg University Gynecological Clinic because of a discrepancy between calculated and biologically determined gestational age, the suitability of the Doppler Flow examination method (duplex method) for resolving this question was studied. The signals from the fetal descending aorta, the umbilical artery, and from maternal placental vessels were used. An A/B ratio of over 7 in the fetal aorta, an A/B ratio of over 4 in the umbilical artery, and detection of an early diastolic incisure in the so-called arcuate arteries were considered pathologic. The relatively high accuracy of this examination method is expressed by its sensitivity (91%) and likewise high specificity (86%) for this diagnostic question. In view of the predictive value of 88% thus determined, reliable differential diagnostic distinction between intrauterine growth retardation and uncertainty regarding term appears possible. Doppler sonographic examination can be performed without causing any serious discomfort to the patient and within a short period of time. While the number of false-positive results in this study was in any case relatively low (11%), an in-depth analysis showed that an "acute placental insufficiency" had occurred in the peripartum in more than one-half of the cases.

Aorta, Thoracic↗
PubMed1988

[Amniocentesis following premature rupture of fetal membranes and suspected premature rupture of fetal membranes in late pregnancy].

Amniocentesis during the third pregnancy trimenon in case of suspected premature rupture is performed for two reasons: on the one hand, the maturity parameters can be determined as usual from the amniotic fluid, and on the other hand it serves to determine the presence of germs that may have caused the premature rupture. At the same time, it is possible to confirm the suspicion of premature hydrorrhoea gravidarum by instillation of dyestuff into the amniotic cavity. Premature rupture was confirmed in 21 of 65 cases where clinical findings had not supplied safe evidence; in the remaining 44 cases this method permitted the exclusion of premature hydrorrhoea. An evaluation was performed by means of a retrospective study of parturitions between 1975 and 1985 with regard to late amniocenteses in cases of suspected premature rupture, the investigated parameters being the course of pregnancy and of birth, postpartal state of well-being, bacteriological findings in the amniotic fluid, and results of instillation of blue dyestuff.

Amniocentesis↗
PubMed1988

[Criteria in the evaluation of breast sonography].

The use of sonography to diagnose pathologic changes of the breast is constantly increasing. It is well known that this method can be employed to distinguish cystic from solid processes. Of greater interest is the question as to the usefulness of sonography in prognosticating the pathology of such processes. This prognosis of pathology is linked to assessment criteria which are not uniformly defined worldwide and which are also applied differently. The study reported here--an evaluation of 755 sonographic focal findings--points out the possible distinctiveness of each individual assessment criterion and indicates the degree of confidence with which malignant and benign breast processes can be distinguished. There are statistically significant differences (p less than 0.0001) in the patterns of distinctiveness of all the assessment criteria mentioned depending on whether the processes are malignant or benign. The most important criterion is the edge contour. Every sonographic focus finding should be checked with regard to its edge contour, retrotumorous acoustic behavior, echo structure, and echo density. In the dynamic part of the examination, changes in the form and structure of the finding must be recorded. The authors estimate the changes of being able to distinguish malignant from benign processes on the basis of the above-mentioned criteria as good. The guide to the classification of echographic phenomena presented here may be of help to learners.

Breast↗
PubMed1988

[Diagnosis of occult fallopian tube cancers by intraoperative peritoneal cytology].

Clinical and ultrasonographic examination are the usual methods of diagnosis for carcinomas of the fallopian tubes and ovarian carcinomas. It is only in rare cases that the diagnosis is based on the cytology of the cervical smear. The use of cytology--more exactly, the cytological examination of secretion in Douglas' space in cases of vaginal hysterectomies--for the detection of ovarian and tubal carcinomas that cannot be diagnosed by clinical and paraclinical procedures, is a rather unusual and rarely described method. However, it is quite justified, as demonstrated by the detection of two carcinomas of the fallopian tubes within a short time.

Adenocarcinoma↗
PubMed1988

[Preoperative diagnosis, pathologic anatomy and clinical significance of mucoceles of the appendix from the gynecologic viewpoint].

Owing to their proximity to the true pelvis and their topography, mucoceles of the appendix frequently cause clinical symptoms which call a gynecologic condition to mind. Sonographically, the structures of mucoceles are often similar to those of ovarian tumors. Within 12 months four patients with mucoceles underwent surgery at Heidelberg University Gynecological Clinic following diagnosis of a gynecologic disease (two tentative diagnoses of ovarian carcinoma, one of advanced ovarian carcinoma, one chance finding during Wertheim's operation). The problems of this rare condition are discussed with reference to the clinical findings, the intraoperative site, and the different morphology and maturity. Pathoanatomically and biologically, however, the clinical picture is not uniform. In mucoceles there is an accumulation of mucus with cystic dilatation of the lumen of the appendix. This is usually due to a tumor, which may be anything from a simple mucous membrane hyperplasia with extreme mucous formation, or an adenoma, to a mucilaginous adenocarcinoma. The rupture of a mucocele or metastasization of a carcinoma often lead to peritoneal mucous spread or peritoneal metastasization: in their patterns of distribution these are similar to a pseudomyxoma peritonei or a metastasizing ovarian carcinoma.

Aged↗
PubMed1988

[Vascular abnormalities of the umbilical cord--incidence, significance and possibility for prenatal ultrasonic detection].

Vascular anomalies of the umbilical cord are amongst the most frequent congenital malformations, their incidence being 0.2% to 1.4%. As a result of the latter the risk of occurrence of other malformations and chromosomal anomalies is markedly elevated. Between January 1977 and July 1987 a total of 78 cases (0.51%) of umbilical cord vascular anomalies were recorded at the Department of Gynaecology of the University of Heidelberg. Malformations occurred in 37% of the foetuses involved. 28% showed retarded growth and 9% had an abnormal set of chromosomes. Anomalies of the urinary tract and malformations of the thoracic organs were very frequent. Total mortality after the 28th pregnancy was about 14%. Currently available high-resolution real-time ultrasound equipment can show up even prenatally pathological variations of the umbilical vascular pedicle (e.g. a single umbilical artery). Because of the manifold risk involved, routine ultrasound control is recommended. If this anomaly is diagnosed, the pregnancy should be classified and treated immediately as a high-risk pregnancy.

Abnormalities, Multiple↗