Search PubMed⌕ Search

Biomedical subjects

M Schmidt

Publications and source records attributed to M Schmidt.

At least 595 records · Page 33Linked to original sources
PubMed1993

Import of phosphatidylserine into isolated yeast mitochondria.

A yeast phosphatidylserine transfer protein was used as a tool to transport radioactively labeled phosphatidylserine from unilamellar vesicles to isolated mitochondria of the yeast, Saccharomyces cerevisiae. Import of phosphatidylserine into mitochondria was monitored by the appearance of radioactively labeled phosphatidylethanolamine, which is produced from phosphatidylserine by the action of phosphatidylserine decarboxylase. This enzyme is located on the outer aspect of the inner mitochondrial membrane. Import of phosphatidylserine into mitochondria and formation of phosphatidylethanolamine does not require ATP or an electrochemical gradient, and is not affected by adriamycin. Evidence is presented that contact sites between the two mitochondrial membranes are zones of intramitochondrial translocation of phosphatidylserine and phosphatidylethanolamine. When phosphatidylserine decarboxylase is inhibited by hydroxylamine, transport of phosphatidylserine to the mitochondrial surface is unaffected. Under these conditions only a small amount of phosphatidylserine accumulates in the inner mitochondrial membrane indicating that the intramitochondrial transport of phosphatidylserine and its metabolic conversion to phosphatidylethanolamine are linked processes.

Carboxy-Lyases↗
PubMed1993

Structure identification of natural rhamnolipid mixtures by fast atom bombardment tandem mass spectrometry.

Two rhamnobiose-lipid preparations have been studied by fast atom bombardment (FAB) tandem mass spectrometry. The principal rhamnobiose-lipids contain the beta-hydroxydecanoyl-beta-hydroxydecanoate Rha-Rha-C10-C10 and the beta-hydroxytetradecanoyl-beta-hydroxytetradecanoate Rha-Rha-C14-C14. Both preparations contain minor components which are heterogenous in beta-hydroxy fatty acid composition. FAB ionization of rhamnobiose-lipids in the presence of Na+ shows the formation of both [M + Na]+, [M +2Na-H]+, [M + 3Na-2H]+ and [M - H]- ions. Tandem mass spectrometry of the [M + 2Na-H]+ and [M - H]- ions give information about the sequence of the building blocks. Particularly, heterogeneity in beta-hydroxy fatty acid composition is determined for the principal components and all the minor components present in the preparations.

Carbohydrate Sequence↗
PubMed1993

Chondrotoxicity of quinolones in vivo and in vitro.

Chondrotoxicity is a rare toxicological finding which is observed in dogs after administration of quinolone antibacterials. To study this effect chondrocytes from articular cartilage of dogs were isolated, and incubated with quinolone derivatives. The effects on cell viability, mitochondrial dehydrogenase, and proteoglycan synthesis were determined. These results were compared with in vivo findings in dogs treated with these quinolones. It was concluded that inhibition of mitochondrial dehydrogenase activity and of proteoglycan synthesis are major reasons for cartilage damage. Therefore this in vitro model is capable of identifying strongly arthropathogenic quinolones without the need of performing animal studies.

Animals↗
PubMed1993

[Rehabilitation of fresh, surgically managed anteromedial knee instabilities].

In between 1983 and 1988, 33 patients suffering from an acute antero-medial instability of the knee were operated on for the anterior cruciate ligament. The reconstruction of the ligament was performed by transcondylar fixation. 25 of these patients took part in a retrospective examination. The postoperative treatment had been carried out according to various concepts of rehabilitation. Our investigations were supposed to measure the restoration of the muscular efficiency of the knee-extensor and -flexor by isokinetic training arrangements. The results revealed that by the operation a sufficient stabilization of the knee had not been achieved. 18 of 25 patients once more showed an antero-medial instability of the knee. Twelve of these 25 patients had an extended anterior instability. Only in seven cases the muscular system was completely restored with average isokinetic muscle efficiency. The high rate of postoperative knee-instability proves the persistent sports-incapacity. We must draw the conclusion that the after-treatment of ligamentous injuries about the knee must focus on the muscular rehabilitation.

Adult↗
PubMed1993

Follicular dynamics prior to and during superovulation in heifers.

The present ultrasonographic study examined the relationship between certain follicular parameters and the superovulatory response in gonadotropin-stimulated heifers. Thirty heifers received a total of 35 mg FSH twice daily for 4 d and 0.75 mg cloprostenol were given to induce luteolysis and estrus at 72 h after the initial FSH injection. Transrectal ultrasonography was performed once daily from 1 or 2 d before the initial FSH injection and until the day of estrus. The number of small (2 to 4 mm), medium (5 to 9 mm), and large (>/=10 mm) size follicles as well as the diameter of the large follicles were recorded. Embryos were recovered non-surgically 6 or 7 d after estrus, and the number of corpora lutea was determined by palpation per rectum. Heifers with >2 or </=2 corpora lutea were classified as responders or nonresponders, respectively. All follicular categories were affected by treatment with FSH in the responders (P<0.0001), while in the nonresponders only small follicles and the total number of follicles showed a change after treatment (P<0.05). All follicular categories were different between the 2 groups (P<0.005). There was no effect of corpus luteum location (ipsilateral vs contralateral) on any of the follicular categories (P>0.05). The number of large follicles and the sum of medium and large follicles were positively correlated (r=0.43 and r=0.54, respectively; P<0.05) with the number of corpora lutea palpated on the day of embryo recovery (6 to 7 d after estrus). In conclusion, there was an effect of the day relative to initiation of FSH treatment on all follicular categories in heifers responding positively to superovulation, and there was no effect of side (left or right ovary) or of corpus luteum diameter (ipsilateral or contralateral).

Journal Article↗
PubMed1993

The immune response to different doses of inactivated hepatitis A vaccine.

The immunogenicity and reactogenicity of different doses of hepatitis A vaccine was studied in healthy adult volunteers. Vaccinees (105) were immunized with 6.25, 12.5 or 25 ng of HAV antigen, each dose administered at 0, 1 and 6 months (groups B, C and D); one group (group A) obtained three 6.25 ng doses at 0, 1 and 2 months. After one single dose high seroconversion rates ranging between 63 and 85% were observed in all four groups. All participants had seroconverted after the third dose, irrespective of the antigen content per dose and the vaccination schedule. Geometric mean titers after three doses were 439 IU/l (group A, month 3) and 1492, 963 and 2772 IU/l in groups B, C and D at month 7. One year after the first injection all vaccinees tested still showed antibody levels well above 10 IU/l. The vaccine was very well tolerated. Minor localized symptoms were observed mainly such as slight pain at the injection site. These symptoms were not dose related; no serious side effects occurred.

Adult↗
PubMed1993

[Pulmonary nocardiosis].

The radiological appearances and pulmonary changes during the acute stage and after recovery from pulmonary nocardiosis are described on the basis of 10 confirmed cases. Amongst the 10 patients there were 3 with malignant disease, 1 patient with AIDS, 3 patients following organ transplantation and 3 patients on steroids. In one patient cerebral involvement was demonstrated by MRI.

AIDS-Related Opportunistic Infections↗
PubMed1993

Malingering and other validity considerations in the neuropsychological evaluation of mild head injury.

Eight malingerers (MPs) were identified via significantly below-chance symptom validity testing (SVT) within a sample of 106 consecutive admissions for neuropsychological evaluation. The resulting incidence of 7.5% is seen as a minimal estimate of malingering within the sample. Eight individuals who "passed" SVT but produced neuropsychological data of questionable validity were also identified (QVs). MPs and QVs were compared with matched controls on 14 measures that have been previously suggested as indicators of invalid neuropsychological data. MPs and QVs differed from controls on General Neuropsychological Deficit Scale, Fingertip Number Writing, and Digit Span. CVLT Recognition, Finger Agnosia, and Speech Perception differed for one of the target groups versus controls and had trends toward significance in the other group. However, many of the previously suggested invalidity signs were rare or absent. Reliance on these measures could result in overconfidence in the validity of neuropsychological data.

Adult↗
PubMed1993

Efficacy and tolerability of tropisetron and dexamethasone in the control of nausea and vomiting induced by cisplatin.

A multicentre study was performed at four oncology centres in Sweden, in 160 chemotherapy-naive women, primarily with ovarian or endometrial carcinomas. Abdominal surgery preceded chemotherapy in 146 (91%) women, and another 39 (24%) women had a history of radiotherapy. The chemotherapy regimens contained cisplatin (50-100 mg/m2), in combination with a variety of other agents. In Course 1, all patients received tropisetron (5 mg i.v. Day 1; 5 mg p.o. Days 2-6) and 84% of patients achieved total or partial control of vomiting; 95% of patients achieved total or partial control of nausea during the first 24 hours. Vomiting was least successfully controlled on Day 2 (73% total or partial control) and Days 2-4 for the control of nausea (81, 83, 88% total or partial control, respectively). Patients with partial response in Course 1 (39% of patients) were randomized to addition of dexamethasone or placebo in Course 2. In Course 2, tropisetron plus dexamethasone (Group B2) prevented acute vomiting in 75% of patients, compared with 40% of patients receiving tropisetron plus placebo (Group B1). Over the entire 6 days, there was no vomiting at all in 54% and 20% of B2 and B1 patients, respectively. In Course 2, acute nausea was prevented in 75% of patients (receiving B1) and in 37% of patients (receiving B2). For nausea, over the complete 6 days, the figures were 64% and 3% (p < 0.001). This indicated that patients with incomplete control of emesis in Course 1 benefited from the addition of dexamethasone, provided that it was added for each of the 6 days studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

The effect of phenylephrine bolus administration on left ventricular function during isoflurane-induced hypotension.

By using transesophageal echocardiography, we examined the effect of phenylephrine (PHE) bolus administration on left ventricular function in 16 patients with no known cardiovascular disease during isoflurane-induced hypotension. PHE was compared with norepinephrine (NE). The patients received an intravenous bolus of PHE (2 micrograms/kg) or NE (0.1 microgram/kg) in random order. The second substance was administered after levels of arterial blood pressure and heart rate returned to baseline levels. We determined fractional area change, end-systolic wall stress, and rate-corrected mean velocity of circumferential fiber shortening. Both substances effectively restored arterial blood pressure. However, after PHE, fractional area change decreased from 0.45 to 0.31 (mean) and rate corrected mean velocity of circumferential fiber shortening from 0.88 to 0.57 circumference/s, whereas both variables remained unchanged in response to NE. End-systolic wall stress increased after PHE and NE from 47.4 to 91.2 and from 54.0 to 65.2 10(3) dyne/cm2, respectively. We conclude that phenylephrine, given as intravenous bolus to patients under isoflurane hypotension, causes a transient impairment of left ventricular systolic performance.

Adult↗
PubMed1993

[Supra-systolic elevation of the intra-cavernous pressure secondary to stimulation of the glans penis].

The role of the perineal muscles in human penile erections is still controversial. The authors investigated surface electromyographic activity of the ischiocavernous muscles together with intracavernous pressure recordings during pressure stimulations of the glans penis. Successive glans stimulations were associated with ischiocavernous muscle contractions and increases in intracavernous pressure reaching two- to fourfold the systolic blood pressure. High correlation coefficients were found between electromyographic and intracavernous pressure amplitudes. Voluntary contractions were accompanied by intracavernous pressure peaks of similar durations, and areas delineated by integrated electromyographic and intracavernous pressure curves showed very high correlation coefficients. Anaesthesia of the dorsal nerve resulted in dramatic reductions of muscle activity and intracavernous pressures in response to glans stimulation. These results suggest that the activity of the muscles in response to pressure stimulation of the glans penis is important to augment rigidity during vaginal penetration and intercourse due to their ability to increase intracavernous pressures.

Adult↗
PubMed1993

[Considerable increase in the perineal arterial flow secondary to stimulation of the glans penis].

The authors investigated the changes in human perineal blood flow by Doppler ultrasonography before, during, and after pressure stimulations (30,150 mm Hg) applied to the glans penis. We found a local increased blood flow response in 72% of 50 patients who consulted our center for erectile dysfunctions. Precise measurement analyses of 10 of these subjects allowed us to further characterize this response. Its latency ranged from 0.1 to 0.8 sec. and its duration from 4 to 13 sec. The blood flow increased up to 8 times the prestimulation level. This consistent increase in perineal blood flow showed much less variability than either the latency or duration of the response. The results of this study suggest that intravaginal pressures exerted on the glans penis during vaginal penetration and intercourse trigger an augmentation of blood flow into the corpora cavernosa. The reflex nature of this response is currently under investigation.

Adult↗
PubMed1993

[Results of treatment of multiple ventral shoulder dislocation and surgical stabilization by Weber rotational osteotomy. 78th Annual Meeting of the Swiss Society of Trauma Surgery and Occupational Diseases 4-5 September 1992 in Olten].

The treatment of recurrent anterior shoulder dislocation with the rotational humeral osteotomie by Weber showed best results in the follow-up of 53 operations when combined with a shortening of the capsule and the musculus subscapularis. Rotational humeral osteotomie alone showed in 20% redislocations. The rate of redislocation could significantly be reduced by additional shortening of the soft tissue.

Adolescent↗
PubMed1993

[Value of radiologic procedures in diagnosis of osteoporosis of the axial skeleton].

Lateral radiograms of the lumbar spine are compared with quantitative mineralometry of vertebral spongiosa done by computed tomography. In 82% of cases, conventional x-rays of the spine give hints towards an increased loss of bone mass. More than 50% of patients with osteoporosis verified by histology are primarily detected by quantitative mineralometry. There is no strict correlation between the severity of osteoporotic disease and the level of mineral content of bone. Conventional x-radiographs of the spinal column are indispensable for estimation of the degree of osteoporosis. Mineralometry can monitor the course of the disease - either to recognize the onset of osteoporosis or to control therapeutic effects. Mineralometry is of less value in primary, early detection of osteoporosis.

Bone Density↗
PubMed1993

Inspection of clinical investigations by the German health authorities.

Based on the regulations of the German Drug Law of 1976 (Arzneimittelgesetz, AMG) the inspections of clinical investigations by the competent health authorities focus on the protection of the human being taking part in the trial. Standards for the planning, methodology, conduct, report and documentation of clinical trials are laid down in a guideline (Grundsätze für die ordnungsgemässe Durchführung der klinischen Prüfung, Dec. 1987), a kind of national GCP standard which has to be respected by sponsors, physicians and authorities, not only for inspection but also for drug registration.

Clinical Trials as Topic↗
PubMed1993

[Not all wheezing is asthma: on functional laryngospasm].

Functional disturbances of the larynx can obstruct respiratory airflow resulting in dramatic states of dyspnoea or shortness of breath. Whereas in inspiratory functional laryngospasm the diagnosis is suggested by inspiratory stridor and hoarseness, it is often difficult to differentiate between the two expiratory forms, namely, laryngospasm in asthma and laryngeal pseudoasthma on the one hand, and an obstructive disease of the lower respiratory tract on the other. Seven case reports demonstrate the by no means uniform pattern of symptoms, the diagnostics and the unfortunately not always satisfactory possibilities of treatment. Pulmonary functional analysis and laryngoscopy are the most important diagnostic procedures in this regard. Even if it is not always possible to achieve the desired freedom from symptoms by means of respiratory therapy, logopaedics or psychotherapy, a correct diagnosis will nevertheless protect both the patient and the doctor against further useless attempts at drug treatment.

Adult↗
PubMed1993

[Tolerance and effect of short-term theophylline infusions].

Short-term infusions with theophylline or aminophylline are often infused very quickly. The present study aimed at comparing the tolerance and therapeutic effect of a theophylline short-term infusion (420 mg theophylline) and an aminophylline short-term infusion (theophylline component 351.3 mg). We infused 16 adults suffering from chronic obstructive respiratory disease, daily at 7 a.m. with increasing speed of infusion and in the following week the other one, and recorded undesirable effects and actions on pulmonary function and gas exchange. 3 of 16 patients tolerated only slow speeds of infusion, 7 patients had mild side effects and tolerated like the other 6 patients even the shortest infusion time. On the whole, both preparations were equally well tolerated. FEV1 and peak flow improved clearly, but only in the course of the next few hours. Theophylline short-term infusion was markedly more effective in this regard. The prompt and infusion rate-independent improvement of the transcutaneous O2 and CO2 partial pressures, which took place even during the short-term injection period, was independent of the preparation. Our data show that intravenously administered theophylline or aminophylline are therapeutically acutely useful substances. However, there is evidently no need to administer theophylline or aminophylline short-term infusions very rapidly, i.e. at below 20 minutes infusion time.

Adolescent↗