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Biomedical subjects

G Schmidt

Publications and source records attributed to G Schmidt.

At least 127 records · Page 7Linked to original sources
PubMed1997

Methodological limitations of the ESRD Core Indicators Project: an ESRD network's experience with implementing an ESRD quality survey. Medical Review Board of the ESRD Network of New England.

ESRD Network Number 1, composed of Maine, New Hampshire, Vermont, Massachusetts, Connecticut, and Rhode Island, developed a Network Core Indicator Pilot Project using the dialysis units represented on the Medical Review Board. Network 1's Core Indicator Pilot Project aimed to (1) estimate the proportion of end-stage renal disease (ESRD) patients in Network 1 receiving hemodialysis treatments associated with a urea reduction ratio less than 60% to 65%, (2) elucidate the patient characteristics associated with a hemodialysis dose less than 65%, (3) define the processes in the delivery of hemodialysis that limit the provision of an adequate dialysis dose, and (4) initiate the routine collection of measures of dialysis dose, the analysis of those data, and feedback to the participating dialysis units. In the course of the Core Indicator Pilot Project, we observed little uniformity in the sampling method for the postdialysis blood urea nitrogen sample. Thirty-three percent of the hemodialysis units reported that this critical blood sample was drawn immediately before the dialysis treatment was terminated; 25% were obtained immediately at the end of the dialysis treatment and 42% drew the sample > or = 5 minutes after all blood was reinfused to the patient. Especially in the presence of unappreciated blood recirculation in the angioaccess or postdialysis urea rebound, the lack of standardization in obtaining this critical blood sample to support the urea reduction ratio calculation greatly compromises any comparisons of performance across dialysis facilities and may jeopardize patient care. Future ESRD quality improvement efforts must focus not only on the results of the outcome measure but also on the process by which the measure is achieved. These fundamental principles of quality assessment should be considered by policy specialists, payers, providers, and developers of clinical practice guidelines.

Adolescent↗
PubMed1997

[A rare case of metastasis of urinary bladder carcinoma in the pisiform bone. A case report].

Metastases to the hand are rare. The incidence of secondary tumors in the hand is about 0.15%. The lung, breast, and kidneys are the most common sites of primary lesions that metastasize to the hand. The authors report about a 66-year-old female who showed an osteolytic metastatic lesion in the os pisiforme which was ulcerated on the ulnopalmar aspect of the right wrist, 18 months after radical cystectomy because of a bladder carcinoma. In agreement with the patient, as well as with colleagues from the pathological, oncological, and radiotherapeutical field, the hand was not amputated as this was a solitary metastatic lesion.

Bone Neoplasms↗
PubMed1997

Role of Rho protein in lovastatin-induced breakdown of actin cytoskeleton.

The Rho GTPases are involved in actin cytoskeleton organization and signal transduction. They need polyisoprenylation for membrane association and activation. Lovastatin, a hydroxymethylglutaryl coenzyme A inhibitor, prevents isoprene synthesis and thereby lipid modification of the Rho protein carboxy terminus. Because lovastatin causes rounding up of cultured cells, we investigated whether the compound acts on the actin cytoskeleton through Rho proteins. Lovastatin treatment decreased F-actin content in a time- and concentration-dependent manner. G-actin content remained unchanged. In lovastatin-treated NIH 3T3 cells, the amount of Rho protein which was ADP-ribosylated by Clostridium botulinum exoenzyme C3 decreased in membranes and increased in the cytosol fraction. Cycloheximide prevented lovastatin-induced rounding up of cells. However, after microinjection or direct application of exoenzyme C3, cells treated with cycloheximide and lovastatin rounded up again. On the contrary, lovastatin-treated, round Swiss 3T3 cells reverted to a flat morphology when microinjected with dominant active RhoA (Val14RhoA). Escherichia coli cytotoxic necrotizing factor (CNF1) which activates Rho proteins caused flattening of round, lovastatin-treated NIH 3T3 cells. These results suggest that lovastatin affects the actin cytoskeleton through inactivation of Rho proteins.

3T3 Cells↗
PubMed1997

[Results of early intervention in acute finger infections].

In the examination of 66 patients treated for acute felons, we classified the infections of fingers as (1.) cutaneous/subcutaneous felons; (2.) paronychia/subungual felons, (3.) thecal whitlow; (4.) articular/bony felons. Primarily, the therapy was based on early aggressive surgical treatment, and secondly on antibiotics. With the management described we achieved a good to very good result in 76%.

Adult↗
PubMed1996

Evaluation of six anti-gliadin antibody assays.

Two in-house methods developed in gastroenterological laboratories for the detection and quantitation of IgG and IgA antibodies to gliadin (AGA) were compared with three commercially available ELISAs (gluten IgG/IgA EIA, Kabi Pharmacia, Sweden; alpha-Gliatest, Eurospital, Italy; AGA Orkit, Labodia, Switzerland) and one qualitative rapid assay (Gliastick, Eurospital, Italy). 67 acute, biopsy confirmed coeliac disease cases were compared with 54 biopsy confirmed disease controls. The result of anti-endomysium antibody (AEA) testing was available from all cases. The testing of 121 sera in different test systems permitted comparison of the range of concentration and sensitivity of the quantitative IgG and IgA anti-gliadin tests. Each test uses its own arbitrary calibration. To permit direct comparison of the different test ranges the values of the different positive reference sera were converted into Pharmacia arbitrary units (AU). The AGA and IgG tests ranged from 0 to a maximum of 157-430 AU and the maximum IgA test results from 81 to 855 AU. This illustrates the need for an internationally accepted standard. All three EIA kits met the performance claims of the manufacturers and were easy to use. Most results agreed with the clinical diagnosis when the sera were positive for anti-endomysium antibodies. However, AEA negative specimens showed a considerable incidence of positive AGA in non-coeliacs. The study emphasises the need to test for both AGA and AEA in order to reliably diagnose coeliac disease. The qualitative test showed a high degree of false positive results and could be used to monitor the dietary compliance of coeliac patients.

Acute Disease↗
PubMed1996

Biochemical and biological consequences of changing the specificity of p21ras from guanosine to xanthosine nucleotides.

The D119N mutation of p21ras was prepared by site-directed mutagenesis. Its nucleotide binding properties were investigated using fluorescently labelled guanosine and xanthosine nucleotides. Its affinity for guanosine nucleotides is severely reduced, with a concomitant increase in the affinity for xanthosine nucleotides, which leads to an almost complete reversal of base specificity. The protein is a GTPase as well as a XTPase and the hydrolysis reaction can be efficiently stimulated by GAP. Dissociation of XDP from the mutant is stimulated by the guanine nucleotide exchange factor Cdc25Mm in a similar manner to that of GDP from wildtype. The interaction of the mutant with the effector domain of c-Raf kinase or Ral-GEF is normal. In microinjection experiments in PC12 and NIH3T3 cells the protein behaves as an oncogenic mutant due to its high dissociation rate for GDP. However, when the protein is loaded with XDP before microinjection the onset of the oncogenic signal can be efficiently retarded. Thus, the protein behaves initially as wildtype and later as an oncogenic protein.

3T3 Cells↗
PubMed1996

[Changes in the energy and nutrient intake of the population in the first year of German reunification--results of a model study in Potsdam].

A nutritional model study was carried out in Potsdam from December 1990 until December 1991 involving 222 persons at the beginning. Changes of the energy and nutrient intake were evaluated. The trends established in 1991-demonstrated by means of two specific trend parameters-have been discussed with regard to the results of the nutritional situation in the former GDR. First signs for an improvement of nutritional situation were visible (e.g., increase of consumption of vitamin A, ascorbic acid and calcium as well as decrease of consumption of energy and cholesterol).

Adolescent↗
PubMed1996

Determination of Platinum-Group Elements (PGE) from catalytic converters in soil by means of docimasy and INAA.

The nickelsulfide fire assay (docimasy) for the enrichment of platinum-group elements (PGEs) has been modified for the use with small samples and combined with instrumental neutron-activation analysis (INAA). This procedure has been applied to the determination of PGEs exhausted from catalytic converters and deposited in soil near the Wiesbadener Kreuz (highway A3, Frankfurt-Köln). Our results show a considerable enhancement of the Pt (up to 330 ng/g), Pd (6.6 ng/g) and Rh (7.5 ng/g) contents close to the highway.

Journal Article↗
PubMed1996

Biomechanical model of the human knee evaluated by neuromuscular stimulation.

A detailed model of the human knee was developed to predict shank motion induced by functional neuromuscular stimulation (FNS). A discrete-time model is used to characterize the relationship between stimulus parameters and muscle activation. A Hill-based model of the musculotendon actuator accounts for nonlinear static and dynamic properties of both muscle and tendon. Muscle fatigue and passive muscle viscosity are modeled in detail. Moment arms are computed from musculotendon paths of 13 actuators and from joint geometry. The model also takes nonlinear body-segmental dynamics into consideration. The simulated motion is visualized by graphic animation. Individual model parameters were identified by specific procedures such as anthropometric measurements, a passive pendulum test, and specific open-loop stimulation experiments. Model results were compared with experimental data obtained by stimulating the quadriceps muscle of paraplegic patients with surface electrodes. The knee moment, under isometric conditions, and the knee angle, under conditions of freely swinging shank, were measured. In view of the good correspondence obtained between model predictions and experimental data, we conclude that a biomechanical model of human motion induced by FNS can be used as a mathematical tool to support and accelerate the development of neural prostheses.

Biomechanical Phenomena↗
PubMed1996

Taxol content of various Taxus species in Hungary.

The anticancer drug taxol was separated and quantitatively determined in bark and foliage of different Taxus species by high-performance liquid chromatography to prove the presence of taxol in Hungarian Taxus species. The measurements were carried out with photodiode array detection using a porous graphitized carbon column, and a water:dioxan 54:46 v/v eluent. Taxol was established as being present in measurable amounts in each Hungarian Taxus species. According to the results bark was richer in taxol than foliage. It could also be observed that the older the bark or foliage, the more taxol it contained. The validation process proved that the method is reliable and can be used for the separation and quantitative determination of taxol in both the bark and foliage of Taxus species grown in Hungary.

Antineoplastic Agents, Phytogenic↗
PubMed1996

The Xenopus homologue of hepatocyte growth factor-like protein is specifically expressed in the presumptive neural plate during gastrulation.

Using a RT-PCR approach, we were able to isolate a cDNA encoding the Xenopus homologue of hepatocyte growth factor-like protein, which we have termed accordingly Xhl. The deduced Xhl protein consists of 717 amino acids, contains four putative kringle domains and a serine protease-like domain characteristic for mammalian HGF and HGF-like protein. The mRNA of Xhl is exclusively expressed in the midline of the prospective neural plate during the period of neural induction, only. Ectopic expression of Xhl causes a 'spina bifida'-like phenotype with enlargement of neural tissue. Activation of Xhl mRNA transcription can be induced by delayed reaggregation of animal caps and appears to require vertical rather than planar signals from the organizer. These data suggest that Xhl is involved in the formation of the embryonic nervous system of Xenopus.

Amino Acid Sequence↗
PubMed1996

[Paroxysmal supraventricular tachycardia in pregnancy. Value of adenosine and other anti-arrhythmia agents].

Adenosine versus Verapamil and other Antiarrhythmic Drugs: Paroxysmal supraventricular tachycardia is the most common sustained arrhythmia during pregnancy. Verapamil has been the most commonly used agent for the treatment of PSVT with a narrow QRS complex. Potential side effects of verapamil including systemic hypotension, acute heart failure, bradyarrhythmia and heart block may occur in pregnant women; after placental transfer bradycardia, heart block, depression of contractility and hypotension may be induced in the fetus. We report on the case of a 22-year old pregnant woman with hypotension and tachycardia, who was admitted for suspected haemorhagic shock. Indeed, she suffered from paroxysmal supraventricular tachycardia, which was successfully terminated by intravenous adenosine. Because of its known rapid onset, high effectivity, low incidence and brevity of side effects in the mother and comparative safety in the fetus, adenosine seems to be the drug of choice for treating PSVT during pregnancy.

Adenosine↗
PubMed1996

Identification of drugs inhibiting the in vitro metabolism of tacrolimus by human liver microsomes.

1. Tacrolimus, an immunosuppressive macrolide, is metabolized by enzymes of the cytochrome P450 3A subfamily. In this study, 34 drugs were tested for their interactions with tacrolimus metabolism by human liver microsomes. 2. Fifteen drugs which inhibit the in vitro metabolism of tacrolimus were identified: bromocriptine, corticosterone, dexamethasone, ergotamine, erythromycin, ethinyloestradiol, josamycin, ketoconazole, miconazole, midazolam, nifedipine, omeprazole, tamoxifen, troleandomycin and verapamil.

Bromocriptine↗