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Biomedical subjects

S Schmidt

Publications and source records attributed to S Schmidt.

At least 559 records · Page 31Linked to original sources
PubMedDate not supplied

[Quantitative ultrasonic tissue characterization of the cervix - A new predictor for prematurity?].

BACKGROUND: Since the incidence of premature delivery has remained constant for the last decade despite intensive safeguarding methods, the texture features of the uterine cervix were evaluated using quantitative sonographic gray level analysis at different gestational ages. MATERIALS AND METHODS: For this purpose, quantitative ultrasonic tissue densitometry of the uterine cervix was obtained from 30 asymptomatic female patients (group A, mean: 30,3 GA) and compared with values obtained from 16 symptomatic female patients (group B, mean: 29,5 GA) with uterine contractions and shortening of the cervix at similiar gestational ages. Once the two-dimensional transvaginal sonographic measurement of cervical length was completed, a region of interest of constant size was defined in the mid-section of the posterior wall, and the tissue-specific gray scale distribution was determined. RESULTS: Quantitative ultrasonic tissue characterization of uterine cervix was feasible in all 46 patients at all gestational ages. In patients with premature contractions and shortening of cervix the average gray scale values were found to be significantly reduced in comparison with those obtained from asymptomatic patients. These results showed good reproducibility and low intraobserver variability and were found to be independent of the measured cervical length. CONCLUSION: Our results prove that quantitative ultrasonic tissue characterization of the uterine cervix might serve as a new parameter for predicting premature delivery.

Adult↗
PubMedDate not supplied

[Q Fever in pregnancy: a case report and review of the literature].

Endemic occurrence of Q fever among persons in close contact with domestic animals is well known in some rural regions of Germany. The prevalence of antibodies indicating acute Q fever in pregnancy reported in the literature varies between 0.2 % and 4.7 % of the screened population. Q fever in pregnancy initially manifests as placentitis and often leads to premature birth (30 %), growth restriction (46 %), spontaneous abortion (22 %) or fetal death in utero (7 %). Some impairment of pregnancy is observed in over 70 % of cases with seroconversion during pregnancy. Thus Q fever serology should be tested in all pregnant women presenting with atypical pneumonia and/or prolonged fever of unknown etiology. It is of interest that medical staff members in contact with Cociella burnetii infected pregnant women are also at risk of acquiring an acute Q fever infection. We report about a patient presenting with confirmed acute and later chronic Q fever during pregnancy in whom antibiotic treatment with rifampicin and clarithromycin proved to be effective and led to the vaginal delivery of a premature but healthy infant. We believe that maternal serum screening for transmissible infections should also include Q fever serology in certain rural regions.

Adult↗
PubMedDate not supplied

Gender-specific response to interstitial angiotensin II in human white adipose tissue.

Angiotensin II is synthesized locally in various tissues. However, the role of interstitial angiotensin II in the regulation of regional metabolism and tissue perfusion has not as yet been clearly defined. We characterized the effect of interstially applied angiotensin II in abdominal subcutaneous adipose tissue of young, normal-weight, healthy men (n = 8) and women (n = 6) using the microdialysis technique. Adipose tissue was perfused with 0.01, 0.1, and 1 micro M angiotensin II. Dialysate concentrations of ethanol, glycerol, glucose, and lactate were measured to assess changes in blood flow (ethanol dilution technique), lipolysis, and glycolysis, respectively. Baseline ethanol ratio and dialysate lactate were both significantly higher, whereas dialysate glucose was significantly lower in men vs. women. In men, ethanol ratio and dialysate glucose, lactate and glycerol did not change significantly during perfusion with angiotensin II. In women, however, angiotensin II induced a significant increase in ethanol ratio and dialysate lactate and a decrease in dialysate glucose close to values found for men and this response was almost maximal at the lowest angiotensin II concentration used. Dialysate glycerol did not change significantly. We conclude that baseline blood flow and glucose supply and metabolism is significantly higher in women than in men. In men, interstitial Ang II has only a minimal effect on adipose tissue blood flow and metabolism. In women, however, a high physiological concentration of interstitial angiotensin II can reduce blood flow down to values found in men. This is associated with an impaired glucose supply and metabolism. Additionally, Ang II inhibits lipolysis.

Abdomen↗
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[Umbilical blood pH, Apgar scores, and early neonatal mortality].

BACKGROUND: For several decades Apgar scores and umbilical blood pH sampling have been routinely used in the assessment of newborns. The aim of this study was to examine the prognostic value of neonatal survival using population-based data and to put these analyses into context with international studies. MATERIAL AND METHODS: Data from 513,135 live births from the Perinatal Birth Register of Hesse, 1990 - 1999, were used. Death in the first week of life (early neonatal death) was used as endpoint of analyses. Receiver operator characteristic analyses were employed to compare the prognostic value of Apgar scores and umbilical blood pHs independently of cutoffs used. RESULTS: Scores and umbilical blood pH showed a strong association with early neonatal morality. The relative risk of early neonatal mortality in term infants with scores 0 - 3 yields a relative risk of 1193 (95 % confidence interval = 801 - 1778) compared with babies born with scores 7 - 10. Scores at 1, 5, and 10 minutes were superior in predicting early neonatal mortality compared to umbilical blood pH, independent of cutoffs used. CONCLUSIONS: Scores remain essential in the prediction of early neonatal survival. Umbilical blood pH is also strongly and significantly associated with early neonatal death, even though it is much less pronounced than the score. DISCUSSION: The poor mortality prediction of umbilical blood pH sampling in Hesse compared with umbilical blood pH sampling in a large American delivery unit with a highly standardized measuring routine may be explained by a lower proportion of extremely acidotic infants or may be attributable to a decreased proportion of or to a less unified or less reliable measurement of the umbilical blood pH in Hesse.

Acid-Base Equilibrium↗
PubMedDate not supplied

[Changes of fibrinolysis during labour with and without aprotinin application].

OBJECTIVE: The aim of this study was to determine (a) if alpha-2-antiplasmin, plasminogen and plasminogen-activator-inhibitors (PAI 1 - 4) change in the peripartal period, (b) if these changes are explainable by the detachment of the placenta and the release of coagulation factors, and (c) if aprotinin could affect postpartal fibrinolysis when given shortly before delivery. PATIENTS AND METHODS: 84 patients have been examined (41 normal deliveries, 43 cesarean sections). After informed consent and randomization, 30 of these patients were administered 1 million KIU aprotinin (Trasylol(R)) at the latest 15 minutes before delivery (15 normal deliveries, 15 cesarean sections). The results of PAI (1 - 4), alpha-2-antiplasmin and plasminogen were collected shortly before and after delivery and 30 and 120 min after detachment of the placenta. RESULTS: Normal deliveries and cesarean sections without aprotinin showed an evident decrease of PAI (1 - 4) after delivery while alpha-2-antiplasmin and plasminogen values did not change. After administration of aprotinin the activity of PAI (1 - 4) increased slightly after labour in normal deliveries and cesarean sections and then slowly decreased later. alpha-2-Antiplasmin levels increased post partum and then decreased to the original values. Plasminogen did not change. There were no significant differences between normal deliveries and cesarean sections with regard to the three parameters studied in this work. DISCUSSION AND CONCLUSION: Changes in PAI (1 - 4) and alpha-2-antiplasmin after administration of aprotinin could be the result of a minimal demand on the fibrinolytic system. Finally, aprotinin can reduce the consumption of coagulation and fibrinolysis factors induced by detachment of the placenta. This could be used in therapy and prophylactic treatment in high-risk patients (e.g., pre-eclampsia, HELLP syndrome, etc.).

Adult↗
PubMedDate not supplied

[Evaluation of the reproducibility of Doppler ultrasonographic measurements in obstetrics].

BACKGROUND: Are obstetric doppler ultrasonographic measurements of the fetal and maternal flow parameters reproducible? PATIENTS AND METHODS: For internal quality management, doppler ultrasonographic measurements were performed on 81 patients (random screening sample) with an Acuson Sequoia Ultrasound at the Universitätsfrauenklinik Marburg. Successively two experienced investigators measured the umbilical artery, medial cerebral artery, and the uterine arteries. The correlation between the measurements of the two investigators was presented in a spread chart. In order to exclude systematic differences between the measurements, linear regression was analyzed and the distance to the abscissa was calculated. A relative divergence of more than 20% was determined as a non corresponding measurement. RESULTS: The distance of the linear regression to the abscissa was calculated for the four vessels: umbilical artery 0.4 (95% CI; 0.124 - 0.486), medial cerebral artery 0.9 (95% CI; 0.534 - 1.264), right uterine artery 0.2 (95% CI; 0.124 - 0.305), and left uterine artery 0.2 (95% CI; 0.121 - 0.317). Concerning the four arteries, a divergence of more than 20% between the two investigators was found: umbilical artery 16%, medial cerebral artery 42%, right uterine artery 28%, and left uterine artery 37%. CONCLUSIONS: Because the interobserver variability was surprisingly high and acceptable correlation could be stated only for the umbilical artery, internal quality standards are essential. Routine use of different devices should be made after careful consideration only, especially if clinical decisions are to be based on them.

Blood Flow Velocity↗
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[Why are babies born at night at increased risk of early neonatal mortality?].

BACKGROUND: Increased perinatal and neonatal mortality rates have been previously reported in night-time births compared with births during the day. This effect has been attributed to decreased quality of medical care during the night. However, alternative explanations exist such as decreased birth-weight of night births. The objective of this study was to further investigate this relationship. MATERIALS AND METHODS: Data from 590,332 low risk births (singleton births, > or = 2500 g birth-weight, no major congenital anomaly) were obtained from the perinatal birth register of Hesse, Germany, 1990-2000. Outcome was defined as either death during labour or within 7 days of life. Night-time births were defined as births between 9.00 p.m. and 6.59 a.m., otherwise day-time births were assumed. Subgroup analyses and logistic regression analyses were performed to assess whether the excess mortality of night-births might be explained by other factors. RESULTS: Mortality rates were increased in night-time births (RR = 1.26; 95% CI = 0.94-1.70). This relationship was more pronounced in spontaneous births (RR = 1.58; 95% CI = 0.96-2.61) and emergency cesarean sections (RR = 1.76; 95% CI = 1.10-2.82). Significance persisted after adjusting for numerous potential confounders. CONCLUSION: Our results confirm an increased mortality risk for night-time births which could not be explained by other accessible risk factors. This suggests that the increased risk at night might be attributable to a reduced availability to provide appropriate medical care in delivery units at night. DISCUSSION: As mainly the presence of staff is decreased during the night, introduction of better designed shifts can be expected to reduce neonatal mortality.

Cesarean Section↗
PubMedDate not supplied

[Lung maturation during artificial placentation and mechanical lung distension].

An new method of lung maturation during artificial placentation was evaluated during a series of 15 animal experiments in premature lambs (gestational age 125-132 days). Perfusion circuit with interposition of a membrane lung was connected with the umbilical vessels. Extracorporeal CO2-removal (ECCO2-R) and apneic oxygenation were provided during lung distension. The ultramicroscopic pattern approved a maturation of the lung during the procedure showing development of lamellar bodies and surfactant secretion into the alveolar space. The biochemical analysis of the tracheal fluid showed a significant increase of both PC and PG concentrations (3.225 +/- 1.112 mg/100g to 24.228 +/- 3.36 mg/100 g respectively 0.249 +/- 0.11 mg/100 g of 0.622 +/- 0.09 mg/100 g. The biophysical function of the lung was also improved as was shown by a significant increase of the statistical compliance. We conclude that artificial placentation and lung distension might be a new mode of prophylaxis for respiratory distress syndrome in critically immature babies.

Animals↗
PubMedDate not supplied

Synthesis of certain heterodimers expected as HIV-1 reverse transcriptase inhibitors.

Expected for the ability to inhibit HIV replication, we report the synthesis of two heterodimers of the general formula: [2NRTI]-C5-GLY-SUCCINYL-Npiperazinyl-[NNRTI] (18, 19) containing both a Nucleoside Reverse Transcriptase Inhibitor (10, 11) and a Non-Nucleoside Reverse Transcriptase Inhibitor (8) [Trovirdine Analogue belonging of the phenethyl thiazolyl thiourea class] connected through the "succinyl-glycine" spontaneously cleavable linker.

Dimerization↗
PubMedDate not supplied

Hypotonicity and ethanol modulate BK channel activity and chloride currents in GH4/C1 pituitary tumour cells.

AIM: Description of the effects of hypotonic cell swelling and ethanol on maxi Ca2+-activated K+ channel (BK channel) activity and Cl- channel activity in GH4/C1 pituitary tumour cells. METHODS: Whole cell-, cell attached- and outside-out patch clamp measurements, fluorescence (fluo-3) measurements of intracellular Ca2+ concentration, cell size video monitoring. RESULTS: GH4/C1 pituitary tumour cells respond to both hypotonicity and ethanol with cell swelling which is followed by a regulatory volume decrease (RVD). Tetraethylammonium and 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) induced cell swelling per se and inhibited hypotonicity induced RVD. Ethanol-induced swelling is paralleled by an increase in the intracellular Ca2+ concentration and augmented by DIDS. BK channel activation by hypotonicity and ethanol is demonstrated in patch clamp experiments both in intact cells (cell attached configuration) and a subset of excised membrane patches (outside-out configuration). Cell swelling and addition of ionomycin under isotonic conditions leads to the activation of outwardly rectifying Cl- currents with time dependent activation at positive potentials. CONCLUSIONS: In GH4/C1 cells both hypotonicity and ethanol lead to cell swelling, RVD and to activation of BK channels. The hypotonicity-induced BK channel activation can also be observed in cell free outside-out patches. Hypotonicity, but not ethanol leads to the activation of Cl- channels with features of Ca2+-activated Cl- currents.

3T3 Cells↗
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Protein translocation into mitochondria.

The biogenesis of mitochondria requires the translocation of most mitochondrial proteins across two biological membranes. Mitochondrial preproteins are synthesized in the cytosol carrying targeting information, that is recognized by specific receptor proteins. The precursor polypeptides are transported across both mitochondrial membranes via three large integral membrane protein complexes forming specialized preprotein translocases. A soluble protein complex in the matrix provides the ATP-dependent translocation force, responsible for the movement and unfolding of the bulk polypeptide chain. After the removal of the targeting sequence, imported proteins fold into their native conformation with the help of chaperone proteins in the mitochondrial matrix.

Biological Transport, Active↗
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[Pilot study of the relationship between attachment styles and problem perception in a sample of 9-11 year old children with behavioral disorders].

Using the Separation Anxiety Test, this study assessed the attachment patterns in a sample of 27 boys and girls in psychotherapeutic treatment to test the hypothesis of a relationship between attachment styles and problem perception (using the problem questionnaire of Westhoff), and concentration. In conformity with the hypothesis, results demonstrate children with anxious-avoidant attachment showing less, those with anxious-ambivalent attachment indicating more problems than average. There was a general tendency for children with behavioral disorders reporting more problems than a comparative sample of 19 school children. No correlation was found between attachment styles and concentration (assessed via the d2-test). The concentrative abilities were generally reduced in the clinical sample. The results are discussed in relation to action-theoretical assumptions.

Anxiety, Separation↗
PubMedDate not supplied

[Intracranial hemodynamics in phenobarbital administration].

The effect of phenobarbital application on cerebral hemodynamics was studied in premature lambs. Near infrared spectroscopy was used for noninvasive monitoring of oxyhemoglobin, deoxyhemoglobin, total hemoglobin and cytochrom a/a3. Total intracranial blood volume decreased shortly after giving the drug and remained then on a stable lowered niveau. This could be explained with shifting of blood in different brain regions or with a decreased total intracranial blood volume.

Animals↗
PubMedDate not supplied

[The influence of umbilical cord compression on the fetal brain--an animal experiment using laser spectroscopy].

In order to evaluate the influence on the fetal brain due to compression of the umbilical cord biochemical and biophysical changes were traced during defined occlusions of 60 sec by means of NIR laser spectroscopy. Synchronously blood samples were drawn intermittently from a catheter positioned in the A. carotis and analysed for blood gases. The saturation values measured in the fetal blood correlated significantly with the dates of the HbO2 tracing of the NIR-system (r = 0.81, p less than 0.001). After induced occlusion of the umbilical cord a reproducible pattern of the NIR tracing occurred. While an immediate fall in HbO2 occurred, a synchronous rise in desaturated Hb was observed. For the changes of the cytochrome aa3 we detected a minor decrease that occurred with a lag time. Additionally there was an indication of a major change of blood volume as the total Hb content augmented during each compression. We concluded: Changes of Hb-saturation in the fetal blood are immediately indicated by NIR-laser spectroscopy. During cord occlusion of 60 sec. the intracellular oxygenation decrease only after a significant lag time and are reversible and furthermore it leads to a reproducible change of intracerebral blood volume.

Animals↗
PubMedDate not supplied

Clinical pharmacology of 1-beta-D-arabinofuranosyl-5-azacytosine (fazarabine) following 72-hour infusion.

The clinical pharmacology of fazarabine (1-beta-D-arabinofuranosyl-5-azacytosine), a structural analogue of 1-beta-D-arabinofuranosylcytosine (ara-C) and 5-azacytidine, was assessed in 14 patients with various malignancies during a phase I trial. Since the starting dose for the protocol was low (0.2 mg/m2/hr over a 72-hr continuous iv infusion), a radioimmunoassay (RIA) using commercially available ara-C antibody and [3H]ara-C was developed to measure the anticipated low plasma drug levels. The assay could be used to measure fazarabine accurately in plasma and urine with a sensitivity of 0.08 ng/ml. The RIA does not require extraction of samples. Using both RIA and HPLC, similar results were obtained in plasma samples from a patient receiving a high dose (180 mg/m2/hr) of fazarabine. The assay is simple, sensitive, reproducible, and specific. Following the infusion, plasma levels declined triphasically with a terminal half-life of 5.7 +/- 2.0 hr. The AUC was linearly related to dose. When the various doses were normalized to 1.75 mg/m2/hr (the maximum tolerated dose as determined from the phase I trial) the mean AUC value was 4232 +/- 987 (ng/ml)hr. Plasma steady-state drug levels (CPss) were achieved in 2-4 hr and were linearly dependent to dose. Also, when normalized, the mean CPss was 58 +/- 13 ng/ml, which is within the reported concentration range necessary for inhibiting malignant cell growth. Total clearance was rapid, 528 +/- 138 ml/(m2.min), and not dose-related.

Adult↗
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5-Fluorouracil and recombinant interferon alfa-2a: review of activity and toxicity in advanced colorectal carcinomas.

Improved response rates in metastatic colorectal carcinoma recently have been observed for the combination of 5-fluorouracil (5-FU) and recombinant interferon alfa-2a (rIFN), compared to those obtained in historical trials of single-agent 5-FU. The mechanism of interaction between these agents has not been explored adequately but may relate to biochemical modulation of 5-FU by rIFN. Toxicities resulting from this combination have included fever, chills, myalgias, granulocytopenia, mucositis, diarrhea, skin rash, neurological symptoms, and hand-foot syndrome. Future studies of 5-FU with rIFN should investigate schedules aimed at reducing toxicity without compromising efficacy and also should explore mechanisms of enhanced activity.

Aged↗
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[Hemodynamic adaptation during extracorporeal perfusion and arteriovenous extracorporeal CO2 removal].

During an animal study using five bastard dogs the hemodynamic relations during extracorporeal perfusion with an arteriovenous circuit and extracorporeal CO2 removal (ECCO2-R) were analyzed. We utilised a prototype circuit (Promed, West-Germany) which is by diminution and using silicon rubber adapted to the application in newborn. A silicon lung (Scimed, 0.8 m2, ECCO2-R) was used in the circuit. During the six hours perfusion period a main arterial blood pressure of 83 +/- 17 mmHg and an extracorporeal blood flow of 412 +/- 56 ml/min was found using arteriovenous perfusion via the femoral artery and vein. We found a statistical significant correlation (r = 0.66) between the main arterial blood pressure and the extracorporeal blood flow. Further more there was a significant correlation between the arterial PCO2 and the blood flow through membrane lung (r = 0.81). In conclusion our animal experiments approved the possibility of hemodynamic adaptation to an arteriovenous circuit as well as effectiveness of CO2 removal via such circuit.

Animals↗