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Biomedical subjects

A Schmitz

Publications and source records attributed to A Schmitz.

At least 109 records · Page 6Linked to original sources
PubMed1995

Influence of 3,4-dichloroaniline (3,4-DCA) on benthic invertebrates in indoor experimental streams.

The influence of 3,4-dichloroaniline (3,4-DCA) on benthic invertebrates has been examined. Acute toxicity tests were carried out with the following species: Pristina longiseta, Aelosoma variegatum (Oligochaeta), Hydrozetes lacustris (Acarina), Planorbarius corneus, and Gyraulus albus (Planorbidae). LC50 values (96 hr) were obtained for Pri. longiseta (2.5 mg/liter) and for Hy. lacustris (4.7 mg/liter). For all other species ranges of toxicity (maximal concentration with 0% dead to minimum concentration with 100% dead) were determined. These ranges were 0.8-20 mg/liter 3,4-DCA for Pri. longiseta, 1.6-20 mg/liter, 3,4-DCA for Hy. lacustris, 10-20 mg/liter 3,4-DCA for G. albus, 50-100 mg/liter 3,4-DCA for Pl. corneus, and 10 mg/liter 3,4-DCA (maximal concentration with 0% dead; minimum concentration with 100% dead was not determined) for Ae. variegatum. In two experimental streams, the recolonization of benthic organisms into defined sample areas was studied. Therefore, a phase without chemical treatment was compared with a following exposure phase. Test concentrations were 0.2 and 1.4 mg/liter 3,4-DCA (nominal concentrations). Significant effects were the complete extinction of Pri. longiseta in 0.2 mg/liter 3,4-DCA within the first 3 weeks of exposure, as well as the reduction of immigrating individuals of another species of Pristina in both test concentrations, and of Hy. lacustris and Stentor sp. in 1.4 mg/liter 3,4-DCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Aniline Compounds↗
PubMed1995

A linkage map with microsatellites isolated from swine flow-sorted chromosome 11.

We have developed a simple and efficient method to construct partial libraries of swine Chromosome (Chr) 11, starting with only 300 flow-sorted copies. DNA is amplified by PARM-PCR with primer containing at the 5'-end the sequence AGCU-. After amplification, digestion of PCR products with uracil DNA glycosylase generates cohesive ends corresponding to the SstI site. The amplified fragments can then be ligated in vector linearized with the SstI enzyme. Using five different primers, we PARM-PCR amplified and cloned swine Chr 11 DNA. These chromosome-specific libraries have been used to develop 14 different (TG)n microsatellites. Ten of these markers were assigned to Chr 11 by PCR analysis of a panel of Pig-Rodent somatic hybrids and by linkage analysis of the 171 individuals of the PiGMaP reference families. A complete linkage map of 147 cM of this chromosome was then realized by integrating existing markers.

Animals↗
PubMed1995

The bovine bivariate flow karyotype and peak identification by chromosome painting with PCR-generated probes.

A bovine bivariate flow karyotype has been established from a primary fibroblast cell culture carrying a 4;10 Robertsonian translocation. From 27 to 36 populations could be resolved by flow cytometry although the anticipated number was 31. Separation of chromosomal pairs into two populations explains this high resolution and confirms the high level of heteromorphism previously observed. We used a PARM-PCR (Priming Authorizing Random Mismatches) procedure for the production of paint probes from flow-sorted chromosome fractions. These probes were used for chromosome identification by fluorescence in situ hybridization (FISH) on R-banded metaphase spreads. We present the localization of all the bovine chromosome types on the flow karyotype. Twenty-two chromosome types including the translocated chromosome were sorted as pure fractions.

Animals↗
PubMed1995

Progress of unrelated bone marrow donor search at the University Hospital of Essen (1991-1994).

The development of unrelated bone marrow donor search (UMDS) was analyzed in a retrospective single-center study covering the period from 1991 to 1994. The data files of the 285 enrolled UMDS patients were evaluated for the patients' underlying disease, HLA phenotype frequency, year of search start, UMDS duration/outcome, and the origin of identified donors. Within 3 months after UMDS start, a donor was found in 5%, 10%, 19%, and 49% of the searches started in 1991 (n = 57), 1992 (n = 73), 1993 (n = 77), and 1994 (n = 78, until September), respectively. The total UMDS success rate increased from 53% (1991 group) to 67% (1994 group), with 5% and 54%, respectively, of the accepted donors being supplied by German registries. Thus, the current UMDS procedure provides a suitable donor for the majority of the patients lacking a related donor, and the majority of the donors are now facilitated by national donor centers.

Bone Marrow↗
PubMed1995

Prorenin and renal function in NIDDM patients with normo- and microalbuminuria.

OBJECTIVES: To assess whether prorenin is elevated and perhaps a predictor of deteriorations in albuminuria and/or renal function in NIDDM patients with normo- and microalbuminuria. DESIGN: A cross-sectional and a longitudinal study. SETTING: Outpatient diabetic clinic. SUBJECTS: Twenty-eight NIDDM patients (16 with normoalbuminuria, 12 with microalbuminuric) and 16 healthy subjects, matched for sex, age and BMI. Fifteen patients were reinvestigated after (mean [range]) 3.1 (2.1-4.3) years. MAIN OUTCOME MEASURES: Serum prorenin and renin, urinary albumin excretion rate, and glomerular filtration rate. RESULTS: Serum prorenin was similar in both normoalbuminuric (116x/divided by) 1.9 microU ml-1 (geometric meanx/divided by antilog SD) and microalbuminuric (124x/divided by) 1.7 microU ml-1) as well as in healthy control subjects (90x/divided by) 1.7 microU ml-1). Prorenin did not correlate to either urinary albumin excretion rate or glomerular filtration rate. No difference between baseline and follow-up levels of albuminuria, glomerular filtration rate or prorenin were observed. The annual changes in albuminuria, glomerular filtration rate and prorenin were not correlated, and no correlation was found between baseline prorenin levels and annual changes in albuminuria or glomerular filtration rate. CONCLUSIONS: Serum prorenin levels are not elevated in either normoalbuminuric or microalbuminuric NIDDM patients, and serum prorenin is not a valid predictor of long-term changes in albuminuria in this patient group.

Aged↗
PubMed1995

Albuminuria and 24-h ambulatory blood pressure in normoalbuminuric and microalbuminuric NIDDM patients. A longitudinal study.

OBJECTIVE: To assess the long-term relationships between 24-h ambulatory blood pressure (AMBP), urinary albumin excretion (UAE) rate, and metabolic control in non-insulin-dependent diabetes mellitus (NIDDM) patients with normo- and microalbuminuria. RESEARCH DESIGN AND METHODS: We conducted a prospective study of 23 NIDDM patients (11 with normoalbuminuria and 12 with microalbuminuria) receiving standard clinical care, including antihypertensive treatment, attending the outpatient clinic and 8 healthy control subjects. Twenty-four-hour AMBP and UAE were measured synchronously in addition to fasting plasma glucose, HbA1c, and serum creatinine at baseline and after 4.6 (4.2-5.1) years [mean (range)]. RESULTS: Baseline systolic, but not diastolic, 24-h AMBP was significantly higher in diabetic patients compared with control subjects (146/80 [16/11] vs. 133/78 [9/9] mmHg, P < 0.05), but was similar in normoalbuminuric (143/81 [11/11] mmHg) and microalbuminuric (148/80 [20/10] mmHg) patients during strict blood pressure control. The annual increase in 24-h AMBP was equivalent in diabetic patients (0.6/-0.2 [2.6/1.5] mmHg/year) and control subjects (0.7/0.2 [1.2/1.4] mmHg/year, NS) and not significantly different from zero. Overall UAE did not change in control subjects (5.6 [1.6] vs. 4.4 [1.9]) (geometric mean [antilog SD]) or in the normoalbuminuric (8.7 [1.7] vs. 11.3 [3.0] micrograms/min) and microalbuminuric (35.7 [2.1] vs. 34.5 [3.2] micrograms/min) patients. In diabetic patients, the annual change in UAE correlated significantly with the annual change in the systolic (r = 0.61, P < 0.002) and diastolic (r = 0.54, P < 0.008) 24-h AMBP. In microalbuminuric patients, only the annual increase in systolic 24-h AMBP correlated significantly with the annual change in UAE (r = 0.71, P = 0.010), whereas in the normoalbuminuric patients, only the annual increase in diastolic 24-h AMBP and the annual change in UAE were significantly correlated (r = 0.66, P = 0.026). In a stepwise multiple linear regression analysis, the annual progression in albuminuria in NIDDM patients was significantly determined by increases in systolic (parameter estimate 0.018, SE 0.006, P < 0.008) as well as in diastolic 24-h AMBP (parameter estimate 0.026, SE 0.011, P < 0.033). CONCLUSIONS: In an outpatient clinical setting, 24-h AMBP is similar in NIDDM patients with normo- and microalbuminuria. Alterations in both 24-h AMBP and UAE are on average moderate and equivalent compared with those in healthy control subjects. Although the average change in albuminuria is small, a progression in albuminuria relates to increments in both systolic and diastolic 24-h AMBP.

Albuminuria↗
PubMed1995

[Towards an allotype of second generation colon cancer].

A subset of genetic alterations distinguishes two groups of colon cancers. In the first group instability of microsatellite loci due to a defective DNA mismatch repair system is observed. The second group is characterized by recurrent losses of chromosome regions, frequently associated with hyperploidization. We have developed a technique which enables a fine description of allelic losses in this second group of tumours. The typing of 278 loci in 47 hyperploid colon cancers has provided information for an average of 160 loci per tumour. The high frequency of allelic losses on chromosomes 17, 18 and 5 was confirmed thus validating our methodological approach. Several additional chromosome segments were observed lost in over 40% of the cases, suggesting that tumour suppressor genes may map within these regions. Further technical development should contribute to the identification of these genes.

Alleles↗
PubMed1994

Monoclonal antibody based enzyme-linked and chemiluminescent assays for the human interleukin-1 receptor antagonist. Application to measure hIL-1ra levels in monocyte cultures and synovial fluids.

Interleukin-1 receptor antagonist (IL-1ra) has the potential to counteract at least part of the biological effects of interleukin-1. The outcome of an inflammatory reaction may therefore be determined by the balance between IL-1 and IL-1ra, rather than by IL-1 alone. We have developed an immunoassay to address this issue as well as to assess the effects of anti-inflammatory agents on the expression of IL-1 and IL-1ra in vitro or in body fluids. Recombinant human IL-1ra was expressed in an E. coli system, purified to homogeneity, and used to derive monoclonal antibodies in mice as well as polyclonal antibodies in rabbits. A sandwich ELISA was constructed with F(ab')2 fragments of a high affinity monoclonal antibody and the rabbit serum as a source of secondary antibody. The assay required no sample treatment to avoid interference by rheumatoid factor. The measuring range was 0.020-2 ng/ml. By labelling a second monoclonal antibody with an acridinium ester, a chemiluminescence assay with a wider measuring range (0.050-15 ng/ml) was generated. In accord with published data, we found that IL-1ra was secreted by human monocytes stimulated with LPS, Zymosan, IL-1 alpha, or human IgG. After an induction phase of ca. 4 hours and depending on the stimulus, IL-1ra accumulated linearly for periods up to 96 h. IL-1ra levels in synovial fluids of 19 patients suffering from various inflammatory joint diseases were compared with the cytokine levels of IL-1 beta, IL-6, IL-8, and TNF-alpha. Highest positive correlations were found with IL-8 and IL-1 beta. In normal blood donors IL-1ra serum levels were 150-800 pg/ml (Median: 387 pg/ml). Owing to its sensitivity and large measuring range the newly developed assays appear to be suitable for measuring IL-1ra in cell cultures as well as in biological fluids.

Animals↗
PubMed1994

Isolation of region-specific probes from pig chromosome 6 by coincidence cloning.

Coincidence cloning is a technique that permits the isolation of sequences common to two independent sources of complex DNA, and this method has been used to isolate a set of probes from a region of porcine Chromosome (Chr) 6 containing the loci for glucosephosphate isomerase (GPI) and the skeletal muscle calcium release channel (CRC). Porcine DNA was specifically PCR-amplified from a pig x hamster hybrid cell line containing the centromere region (p1.2-q1.2) of pig Chr 6 and other pig chromosome fragments by use of a porcine SINE specific primer with an EcoRI site in the 5'-end. Flow-sorted Chr 6 preparations were amplified with the same SINE primer, but with a SalI site in the 5'-end. The products were digested with EcoRI and SalI respectively, combined, denatured, and reannealed. The heteroduplex molecules, containing both an EcoRI and a SalI cohesive end, were selected by cloning in SalI/EcoRI-digested pUC13. Approximately 40% of the primary clones contained a single SalI/EcoRI-insert, indicating that they are coincidence clones. The average insert size was 1.4 kb. Fluorescence in situ hybridization of a pool of 34 coincidence clones to pig chromosomes showed a preferential labeling of the centromere region and of the q2.5-q2.7 region of pig Chr 6. Nineteen coincidence clones were hybridized to SINE-PCR products from flow-sorted pig Chr 6 and to pig x rodent hybrid cell lines. Eighteen clones gave positive signals correlated with the GPI/CRC content of the source DNAs.

Animals↗
PubMed1994

Systolic blood pressure relates to the rate of progression of albuminuria in NIDDM.

We prospectively followed a cohort of 278 non-insulin-dependent (NIDDM) patients for a 6-year period, intending to estimate the rate of increase of albuminuria and to identify clinical variables that influence this increase. At baseline, normo-albuminuria (N) was seen in 74%, microalbuminuria (M) in 19% and 7% presented with proteinuria (P). A total of 80 patients died; they were older (p < 0.001) and had higher albumin excretion both at baseline and as an average during follow-up (p < 0.01). At baseline, patients with proteinuria had higher blood pressures (systolic and diastolic), whereas there was no difference between patients with normo-and microalbuminuria. Glycaemic control was increasingly poor throughout the three groups. At follow-up, an average relative rate of increase of albuminuria (slope) of 17% per year was seen both for patients with complete 6 years, follow-up (n - 135) and patients with at least 4 years follow-up (n = 178). Slope correlated significantly with systolic blood pressure (r = 0.26 and 0.29) in both groups, diastolic blood pressure only in the 4-year group (r = 0.22) and average albuminuria in both (r = 0.31 and 0.24). By multiple regression analyses systolic blood pressure and average albuminuria remained with significant influence on slope. Progression was defined as an increase in the category (e.g. normo- to microalbuminuria) as well as an increase of more than 20% in albumin excretion, and was seen in 46 patients with at least 4 years' follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1994

Enalapril versus bendroflumethiazide in type 2 diabetes complicated by hypertension.

In a double-blind, double-dummy, randomized, multi-centre study, the effects of bendroflumethiazide vs. enalapril on blood pressure, glycaemic control, lipoprotein concentrations and albuminuria were compared in non-proteinuric, hypertensive type 2 diabetic patients; they were treated for 20 weeks with either bendroflumethiazide 2.5-5.0 mg (n = 59) or enalapril 10-20 mg (n = 55). Age, fasting plasma glucose, HbA1c and BMI were similar in the groups. Systolic and diastolic blood pressure were reduced in both groups. Bendroflumethiazide was accompanied by minor but significant elevations in fasting plasma glucose and serum C-peptide. HbA1c was increased during both treatments. Lipoproteins and urinary albumin/creatinine ratio were stable. Bendroflumethiazide caused a decrease in serum potassium and an increase in serum urate. No significant correlations were observed between the decline in blood pressure and changes in the metabolic risk factors. Baseline levels of age, sex, BMI, blood pressure or urinary albumin/creatinine ratio were not related to changes in blood pressure, metabolic parameters or urinary albumin/creatinine ratio.

Adult↗
PubMed1994

A mutational analysis of receptor binding sites of interleukin-1 beta: differences in binding of human interleukin-1 beta muteins to human and mouse receptors.

The 3-D crystal structure of interleukin-1 beta (IL-1 beta) has been used to define its receptor binding surface by mutational analysis. The surface of IL-1 beta was probed by site-directed mutagenesis. A total of 27 different IL-1 beta muteins were constructed, purified and analyzed. Receptor binding measurements on mouse and human cell lines were performed to identify receptor affinities. IL-1 beta muteins with modified receptor affinity were evaluated for structural integrity by CD spectroscopy or X-ray crystallography. Changes in six surface loops, as well as in the C- and N-termini, yielded muteins with lower binding affinities. Two muteins with intact binding affinities showed 10- to 100-fold reduced biological activity. The surface region involved in receptor binding constitutes a discontinuous area of approximately 1000 A2 formed by discontinuous polypeptide chain stretches. Based on these results, a subdivision into two distinct local areas is proposed. Differences in receptor binding affinities for human and mouse receptors have been observed for some muteins, but not for wild-type IL-1 beta. This is the first time a difference in binding affinity of IL-1 beta muteins to human and mouse receptors has been demonstrated.

Amino Acid Sequence↗
PubMed1994

Immunogenetic marrow donor search for 1012 patients: a retrospective analysis of strategies, outcome and costs.

To analyse strategies, outcome and costs of immunogenetic marrow donor search 1012 patients were enrolled in a retrospective single centre study covering the period from January 1990 to December 1992. An HLA-compatible donor was identified for 562 of the patients (55.4%). Core family donor search (CFDS) provided a donor for 39%, extended family donor search (EFDS) for 6.4% and unrelated marrow donor search (UMDS) for 10% of the patients. During the period analysed, UMDS success rate increased from 13.3% to 47.8%, while mean search length decreased from 7.2 to 4.8 months. The percentage of donors from German registries rose from 5% in 1990 to 50% in 1993. Search length was dependent on patient's HLA phenotype frequency, but even for patients with frequencies as low as < 1:3 000 000 a donor was found in 5 of 24 cases. The mean costs (DM) per donor identified by CFDS, EFDS and UMDS were 2921, 19 172 and 24 036, respectively. Thus, CFDS is the utmost effective type of search. In view of the clinical outcome of BMT, EFDS remains a meaningful strategy and should not be replaced by UMDS despite its increasing success rate.

Actuarial Analysis↗
PubMed1993

Accurate characterization of porcine bivariate flow karyotype by PCR and fluorescence in situ hybridization.

The 19 chromosomal pairs of the swine karyotype are resolved into 18 peaks denoted A to Q and Y by dual-beam flow cytometry. The chromosomal content of six peaks has previously been determined by analyzing male/female differences, karyotypes of animals carrying translocations, and PCR studies of genes with known assignments. For the remaining chromosomes, putative assignments to flow peaks were deduced from comparison of DNA contents, determined by flow cytometry, and chromosomal size. We present here the complete characterization of the pig bivariate flow karyotype using the PARM-PCR technique combined with fluorescence in situ hybridization. Chromosome-specific probes were generated by PCR amplification of 300 sorted chromosomes with primers under nonspecific conditions and used to paint chromosomes by FISH. The chromosomal content of each peak was identified: peaks A (chromosome 1), B (13), C (6), D (2), E (14), F (3), G (7), H (9,4,X), H1 (9), I (15), J (8), K (5), L (10), M (12), N (16), O (11), P (17), Q (18), Y (Y). We were able to characterize perfectly the pig bivariate flow karyotype. Such techniques could be applied to any other species.

Animals↗
PubMed1993

Glomerular structure and function in proteinuric type 2 (non-insulin-dependent) diabetic patients.

Glomerular ultrastructure was examined in a series of 20 Type 2 (non-insulin-dependent) diabetic patients with proteinuria. Reference was made to data previously obtained in non-diabetic kidney donors and in Type 1 (insulin-dependent) diabetic patients with similar degrees of proteinuria. The Type 2 diabetic patients demonstrated the changes which characterize the diabetic glomerulopathy seen in Type 1 diabetic patients: basement membrane thickening, and increase in the mesangium and mesangial matrix expressed as fraction of the glomerular volume. Among the Type 2 diabetic patients there was more variation than among the Type 1 diabetic patients, as this group included subjects with normal parameters. The group means and coefficients of variation (= SD/mean) of the glomerulopathy parameters combined in the glomerulopathy index = basement membrane thickness/10+ Vv(matrix/glom).100 were 81 (0.30) and 92 (0.15) in the two diabetic groups, clearly different from the non-diabetic index, 42 (0.16). All Type 2 diabetic patients who also had retinopathy had a glomerulopathy index above the normal range. Similar changes in glomerular composition were seen in the two diabetic groups: with increasing glomerulopathy the volume of matrix dominated over the peripheral basement membrane, and a shift in the ratio of interfaces was seen: mesangial surface towards capillary lumen increased relative to the urinary surface, and peripheral capillary surface comprised less of the total capillary surface. Data indicated marked glomerular hypertrophy, which correlated with the mesangial volume fraction, thus encompassing preserved filtration surface per glomerulus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗