Biomedical subjects

K Grote

Publications and source records attributed to K Grote.

7 recordsLinked to original sources

PubMed1998

Significance of plasmalemma aquaporins for water-transport in Arabidopsis thaliana.

The plant plasma membrane intrinsic protein, PIP1b, facilitates water transport. These features were characterized in Xenopus oocytes and it has asked whether aquaporins are relevant for water transport in plants. In order to elucidate this uncertainty Arabidopsis thaliana was transformed with an anti-sense construct targeted to the PIP1b gene. Molecular analysis revealed that the anti-sense lines have reduced steady-state levels of PIP1b and the highly homologous PIP1a mRNA. The cell membrane water permeability was analyzed by swelling of protoplasts, which had been transferred into hypotonic conditions. The results indicate that the reduced expression of the specific aquaporins decreases the cellular osmotic water permeability coefficient approximately three times. The morphology and development of the anti-sense lines resembles that of control plants, with the exception of the root system, which is five times as abundant as that of control plants. Xylem pressure measurement suggests that the increase of root mass compensates the reduced cellular water permeability in order to ensure a sufficient water supply to the plant. The results obtained by this study, therefore, clearly demonstrate that aquaporins are important for plant water transport.

Animals↗

PubMed1997

Macular hole surgery without face-down positioning. A pilot study.

PURPOSE: To investigate whether postoperative face-down positioning is necessary for successful macular hole repair. BACKGROUND: Although never proven, face-down positioning is strongly considered an important maneuver to achieve macular hole closure. Face-down posturing is inconvenient, and for patients with physical or mental limitations, weeks of face-down positioning may be an impossible task. A gas bubble that completely fills the vitreous cavity will tamponade a macular hole despite head position and may close a macular hole as effectively as a partial gas fill with face-down positioning. If face-down positioning were not necessary, more patients would be eligible to benefit from this surgery. METHODS: Thirty-three consecutive eyes in 31 patients aged 65-79 years with Stage II, III, or IV full-thickness macular holes underwent macular hole surgery with a complete 15% C3F8 vitreous fill. Hole duration varied from 1 month to 10 years; in 21% of eyes, (seven of 33) holes had been present for more than 1 year. All phakic eyes (n = 25) had cataract extraction with intraocular lens insertion when macular hole surgery was done. No patients were positioned face down. RESULTS: The follow-up period was 6-40 months; 73% of the patients have been observed for more than 1 year. Preoperative hole duration did not affect hole closure rate. The success rate after one surgery was 79% (26 of 33 eyes), and with additional vitrectomy surgery, the total success rate was 85% (28 of 33 eyes). Forty-eight percent of eyes attained visual acuity of 20/50. Eighty percent of eyes with preoperative acuity of > 20/100 attained > 20/50 acuity. Significant complications included iris incarceration into the cataract wound during a postoperative fluid-gas exchange (one eye), posterior synechiae (four eyes), intraocular lens capture (two eyes), elevated intraocular pressure (three eyes), and retinal detachment (three eyes). Most of these problems can be avoided or reduced. CONCLUSION: This pilot study suggests that successful macular hole closure is possible without face-down positioning. This technique may be an alternative for patients with macular holes in pseudophakic eyes who are unable to assume face-down posturing. Combining cataract surgery with this technique for macular hole repair is reasonable for phakic patients who cannot maintain prone positioning. Major disadvantages of combined surgery include the morbidity of the second procedure and removal of a visually insignificant cataract. This approach should be considered for those patients unable to tolerate face-down positioning.

Cataract↗

PubMed1996

GenomeInspector: basic software tools for analysis of spatial correlations between genomic structures within megabase sequences.

The speed of acquisition of genomic sequence data exceeds the evaluation of function of the sequences by a vast margin. Most software available for the prediction of individual features does not assess the correlation of different motifs (level 1 methods). Here, we present a second-level software package called GenomeInspector (GI) for further analysis of results obtained with level 1 methods. Our approach does not require any a priori knowledge about motif organization and was designed as a modular package with a graphical user interface. Three examples for GI application are presented.

Genome↗

PubMed1996

GenomeInspector: a new approach to detect correlation patterns of elements on genomic sequences.

MOTIVATION: Most of the sequences determined in current genome sequencing projects remain at least partially unannotated. The available software for DNA sequence analysis is usually limited to the prediction of individual elements (level 1 methods), but does not assess the context of different motifs. However, the functionality of biological units like promoters depends on the correct spatial organization of multiple individual elements. RESULTS: Here, we present a second-level software package called GenomeInspector [[http:@www.gsf.de/biodv/genomeinspector.html ]], for further analysis of results obtained with level 1 methods (e.g. MatInspector [[http:@www.gsf.de/biodv/matinspector.html ]] or ConsInspector [[http:@www.gsf.de/biodv/consinspector.html++ +]]). One of the main features of this modular program is its ability to assess distance correlations between large sets of sequence elements which can be used for the identification and definition of basic patterns of functional units. The program provides an easy-to-use graphical user interface with direct comprehensive display of all results for megabase sequences. Sequence elements showing spatial correlations can be easily extracted and traced back to the nucleotide sequence with the program. GenomeInspector identified promoters of glycolytic enzymes in yeast [[http:@www.mips.biochem.mpg.de/mips/yeast/]] as members of a subgroup with unusual location of an ABF1 site. Solely on the basis of distance correlation analysis, the program correctly selected those transcription factors within these promoters already known to be involved in the regulation of glycolytic enzymes, demonstrating the power of this method.

Algorithms↗

PubMed1986

Cadmium concentrations in autopsy material from differently polluted areas of West Germany (FRG).

Analyses of Cadmium (Cd) in human specimens demand special interest since the Federal Environmental Agency of West-Germany (UBA, FRG) has published calculations and high figures of renal disturbances due to Cd. We analyzed autopsy material from the Cd-polluted area of Goslar/Harz Mountains (N = 28) and from the less contaminated region Erlangen/Nürnberg (Franconia) (N = 50). As determinants of Cd-concentration special regard was given to age, smoking habits, residence (urban/rural), and medical findings (nephropathy, hypertension). A balanced distribution of age is found in all subdivisions, the mean age of death is 66 and 68 yrs., respectively, in both regions. Median values of Cd-concentrations in the target organs from Franconia were found to be half the amount of those from Goslar (renal cortex: 12/19, medulla: 8/16, liver: 1/3 micrograms Cd/g wet weight). Significant local differences are found for renal medulla and liver (p less than 0.05). In both regions the Cd-content is independent from sex and residence (urban/rural). The influence of tobacco smoking on the Cd-burden is evident (greater than 50%). Cases of hypertension show maximum values, although this trend can't be confirmed by the median values. Regional Cd-pollution seems to have more effect than pathological findings: normotensive persons from Goslar have higher median renal Cd-concentrations than hypertensive patients from Franconia. Analyses of renal diseases reveal the same result. All Cd-concentrations are far below the critical value (200 micrograms Cd/g renal cortex, w.w.). The evaluation of such limit values and the results of similar studies are briefly discussed.

Adult↗

PubMed1983

Survival time in cystinosis. A collaborative study.

In a retrospective study the overall survival time of 205 cystinotic patients of six countries was determined. The median survival time was 8.5 years. The median time for 'renal death' (age at death due to uraemia or age at starting renal replacement therapy) was 9.2 years. The youngest patient dying of renal death was 5.2 years. No sex difference in survival time was noticed. Furthermore no difference in survival time was noted between the different countries. The analysis of the overall survival curve indicates no clear differences between the infantile and adolescent types of cystinosis.

Adolescent↗

PubMedDate not supplied

Tissue distribution, toxicokinetics and induction of hepatic drug metabolizing enzymes in male rats after a single s.c. dose of 3,4,3',4'-tetrachlorobiphenyl (PCB-77).

The tissue distribution and toxicokinetics of PCB-77 after a single s.c. dose of 6 mg/kg body weight was investigated in male adult rats as well as the concurrent induction of hepatic drug-metabolizing enzymes. During five days after treatment, the PCB-77 concentrations on fat weight basis in testis and in whole blood were found to be about in the same range as the concentrations in adipose tissue, whereas in liver fat PCB-77 accumulated. EROD and MROD activities were induced by about 8 and 4 times, respectively, during a period of two weeks after treatment. Concentrations in adipose tissue and in liver as well as the hepatic enzyme activities rapidly declined during the investigation period of eight weeks. An elimination half-life for PCB-77 of approximately 7-9 days was estimated.

Adipose Tissue↗