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R Metz

Publications and source records attributed to R Metz.

At least 55 records · Page 3Linked to original sources
PubMed1988

High metabolic activity in the visual cortex of early blind human subjects.

Glucose metabolism has been studied in the visual cortex of early blind human subjects. In the forebrain of these subjects, regional glucose utilization was the highest in the striate and prestriate cortical areas. Furthermore, this activity was higher than in blindfolded sighted subjects, whether at rest or during an auditory or tactile task. These observations raise the question of the functionality of the blind's visual cortex.

Blindness↗
PubMed1988

Macroautophagic phenomena in renin granules.

The secretory granules of murine epithelioid cells take up and probably degrade mitochondria; they thus appear to have macroautophagic properties. As renin granules also have other properties uncommon for secretory granules, they are suggested to fulfill functions in these cells otherwise reserved for lysosomes.

Adrenalectomy↗
PubMed1988

Hypothetical interpretation of the calcium paradox in renin secretion.

Most renin-positive cells of the preglomerular arteriole are intermediate in morphological appearence between smooth muscle cells and epithelioid cells. Intermediate cells contain, in addition to secretory granules, contractile proteins arranged as a sublemmal network. The paradoxical (inhibitory) role of calcium in renin secretion is explained, on the basis of these findings, by an increased tone of the sublemmal network; this might impair the preexocytotic access of renin granules to the cell membrane.

Animals↗
PubMed1988

Interzonal and intrazonal heterogeneities in the renin status of the preglomerular arterioles in five species.

In five species (mouse, rat, rabbit, rhesus monkey and man) the renin status of the preglomerular arterioles was examined using two immunohistochemical methods: the measurement of the renin-positive portion of the vessels, reflecting the respective number of granulated cells, and the semiquantitative assessment of the renin concentration in the juxtaglomerular epithelioid cells with antibody dilution series. The main objective of the study was to compare the interzonal with the intrazonal internephron heterogeneities, i.e. the differences between the average renin status of the preglomerular arterioles in the superficial, intermediate and juxtamedullar cortex with the differences between the renin status of the individual afferent arterioles in one and the same cortex region. In contrast to small interzonal heterogeneities, substantial intrazonal differences in the renin status of the corresponding nephrons were found.

Animals↗
PubMed1988

Cytoplasmic sequestration phenomena in smooth muscle cells of kidney resistance vessels and epithelioid cells of the juxtaglomerular apparatus.

The occurrence of vacuoles in cells of contractile tissues and especially in media cells of resistance vessels has been known for quite some time. Recently, it has been widely accepted that these vacuoles, characteristically lined by a double membrane, result from herniation of one vascular smooth muscle cell into the other as a result of vasoconstriction. In our electronmicroscopic investigations we found double membrane-bounded vacuoles not only in kidney resistance vessels of rats and mice under conditions of vasoconstriction, but also in control animals and animals with maximal renal vasodilation. Part of our observations are compatible with the assumption that such vacuoles arise from a damage of club-shaped, musculo-muscular contacts due to shape changes of media cells during maximal vasoconstriction or vasodilation. However, serial thin sectioning revealed that some of the cytoplasmic vacuoles have no connections with neighbouring cells. This finding and various parallels to the generation of autophagic vacuoles indicate that the so-called herniations may also represent demarcations of large cytoplasmic areas within an individual cell. Irrespective of the origin of these vacuoles, their contents show different stages of deterioration. At later stages, the vacuoles appear to be adjacent, with only one membrane, to the extracellular space, into which they are believed to discharge finally. Cytoplasmic vacuolization has not only been observed in smooth muscle cells, but also in juxtaglomerular epithelioid cells of the afferent arteriole. Here the vacuoles-besides other organelles--also contain secretory granules; it is therefore proposed that autophagic phenomena with final extrusion of cytoplasmic material may be involved in the programmed down-regulation of the granular renin store following inhibition of renin synthesis and secretion.

Animals↗
PubMed1988

Pharmacokinetics and body fluid penetration of fleroxacin in healthy volunteers.

The pharmacokinetics of fleroxacin after oral administration of 400 mg fleroxacin in twelve healthy volunteers were investigated. All drug analysis was carried out by HPLC. Pharmacokinetic analysis was done by non-compartmental methods. We found that fleroxacin achieves high plasma levels of 5.2 +/- 1.1 mg/l after 1.2 +/- 0.7 h. The high AUC-value of 60.4 +/- 8.4 mg.h/l is the result of complete absorption and the long half-life of 10.8 +/- 1.6 h. The total, renal and non-renal clearance of fleroxacin were 107.9 +/- 15.1, 67.6 +/- 11.8 and 40.3 +/- 14.5 ml/min respectively. The volume of distribution Vd beta/F was 101.4 +/- 21.9 or 1.32 +/- 0.28 l/kg. Fleroxacin penetrated well into saliva (66%), nasal secretions (223%), tears (69%) and sweat (43%). On the basis of these findings once a day administration deserves consideration in the further clinical development of fleroxacin.

Adult↗
PubMed1988

Metabolism of fleroxacin in man.

The metabolism of fleroxacin was studied in 12 healthy volunteers by use of a newly developed high pressure liquid chromatographic assay. Desmethylfleroxacin and fleroxacin N-oxide were identified as the major metabolites of fleroxacin in plasma and urine. The maximum concentrations of fleroxacin, desmethylfleroxacin and fleroxacin N-oxide in plasma were 5.2 +/- 1.1, 0.0683 +/- 0.0151 and 0.0634 +/- 0.0090 mg/l reached at 1.2 +/- 0.7 h, 2.2 +/- 0.8 h and 6.2 +/- 2.4 h respectively (one subject excluded from analysis). The plasma AUC was between 1.0 and 2.6 mg.h/l for either metabolite and between 47.9 and 75.1 mg.h/l for the parent compound. The terminal half-life of desmethylfleroxacin was higher than that of unchanged fleroxacin and similar to the half-life of fleroxacin N-oxide. In urine unchanged fleroxacin, desmethylfleroxacin and fleroxacin N-oxide accounted for 59.9%, 6.8% and 6.3% of the dose of fleroxacin. The renal clearance of fleroxacin, desmethylfleroxacin and fleroxacin N-oxide were 67.6, 300.9 and 324.8 ml/min respectively. We conclude that demethylation and N-oxidation of fleroxacin affects the distribution and elimination characteristics significantly. Renal clearance increased, and it is suggested that the volume of distribution may increase also.

Adult↗
PubMed1988

In-vitro activity of fleroxacin against isolates causing complicated urinary tract infections and concentrations in seminal and prostatic fluid and in prostatic adenoma tissue.

Fleroxacin is a new fluoroquinolone with a broad antibacterial spectrum and a serum half-life of about 8-12 h. Eighty percent of 400 isolates from complicated or hospital-acquired urinary tract infections were inhibited by a concentration of 1 mg/l and 95% by 4 mg/l. As with other quinolones, fleroxacin is less active in acid urine (pH 5.4) than in Mueller-Hinton broth (pH 7.4). In 12 healthy volunteers the concentrations of fleroxacin were measured in plasma and seminal and prostatic fluid 2, 4 and 12 h after an oral dose of 400 mg. The mean plasma concentrations of three or four volunteers at each time were 4.2, 3.6 and 1.2 mg/l, respectively. The corresponding prostatic fluid/plasma ratios were 0.30, 0.27 and 1.96, respectively. By concomittant administration of ioxitalamic acid it could be demonstrated that in samples obtained 12 h after administration urinary contamination must be considered. Fleroxacin is concentrated in seminal fluid by a median ratio of 1.7. In 13 elderly patients the prostatic fluid and prostatic adenoma tissue concentrations were determined one to four hours following oral administration of 400 mg. The concentrations in prostatic fluid were similar to those of volunteers. The tissue concentrations exceeded plasma concentrations by only about 10% (median). Fleroxacin is very active against isolates causing complicated UTI. Concentrations in seminal and prostatic fluid and prostatic adenoma tissue are sufficiently high to treat bacterial prostatitis or vesiculitis caused by susceptible bacterial strains.

Adult↗
PubMed1988

Zoladex as primary therapy in advanced prostatic cancer. A French cooperative trial.

From April 1984 to May 1986, 129 patients with prostate cancer entered a prospective trial with a new LH-RH agonist, Zoladex. Mean age was 72 years (range of 45-94 years) and, in most cases, patients had metastatic disease, not previously treated by chemotherapy or hormone therapy. Patients received a monthly injection of 3.6 mg. Serum testosterone was lowered into the range of castrate levels after 4 weeks of treatment. In 105 evaluable patients at 3 months, a 65% partial response (PR) rate was observed, with 11% stable and 24% progressive disease. Median time to progression was 37 weeks. Analysis of objective criteria revealed 30% PR for prostate volume and 51% CR-PR for prostatic acid phosphatases. Seventeen percent of lytic metastases had recalcified. One hundred twenty-nine patients were evaluable for toxicity. Endocrinological side effects were common: decrease in libido, 92%; impotence, 86%; hot flushes, 48%; and breast swelling or tenderness, 9%. Nonendocrinologic side effects were rare. The treatment is generally well accepted by patients owing to the convenient depot formulation and to the minor side effects.

Acid Phosphatase↗
PubMed1988

[Surgical treatment of metastases of the humerus].

Surgical treatment of metastasis disease of the humerus was applied for 46 lesions among 42 patients, i-e 22% of overall osteosyntheses for skeletal metastasis. Two patients only are still alive at 3 and 4 years. The mean survival time is 8.1 months and at 3 months 50% died. Metastasis disease of the humerus becomes evident late during the evolution of the primary cancer, but 26% are revealing lesions. For 9.5% the primary tumor remains unknown. After review of the surgical methods generally used, indirect osteosynthesis by intra-medullary pinning according to Hackethal, without bone cement, is alleged. So the arm is immediately mobilized and a complementary irradiation is applied in post-operative. Prophylactic fixation of impending fractures is encouraged in order to suppress pain, and for better function. This paper demonstrates the changing concept of internal fixation of pathologic fractures and recommends intra-medullary nailing or pinning.

Adult↗
PubMed1986

Development and fate of the secretory granules of juxtaglomerular epithelioid cells.

The development and fate of the secretory granules in murine, rat and human juxtaglomerular epithelioid cells were examined using ultrastructural and immunocytochemical methods. The formation of mature renin granules occurs by fusion of rhomboid protogranules followed by coalescence of their paracrystalline contents, and by the fusion of roundish juvenile granules having an amorphous internum. Protogranules with paracrystalline contents are prominent in animals with stimulated renin synthesis, indicating an overcharge in processing and/or packaging of the secretory product, renin, under these conditions. Various similarities between lysosomes/multivesicular bodies (MVBs) and juvenile renin granules have been observed. With the exception of small MVBs, no renin-negative organelles that could be regarded as lysosomes were found in epithelioid cells of mice and rats. Therefore, we suggest that renin granules are modified lysosomes. Immunocytochemical findings indicate that juvenile secretory granules of epithelioid cells represent the converting and activating compartment for prorenin. Endocytosed foreign tracers such as HRP or cationized ferritin are preferentially internalized by juvenile renin granules, which hence appear to be outstanding by their fusogeneity. Consequently, juvenile granules are probably responsible for the secretion of prorenin, and mature granules for that of active renin.

Angiotensin II↗
PubMed1986

LD-carboxypeptidase activity in Escherichia coli. I. The LD-carboxypeptidase activity in ether treated cells.

The activities of the LD-carboxypeptidases of Escherichia coli K 12 and of a mutant strain 155 with reduced activities were studied with the aid of ether treated cells. Evidence was obtained that was consistent with the suggestion that in both strains two LD-carboxypeptidase activities are present. Activity I degrades the nucleotide activated precursor UDP-MurNAc-tetrapeptide and activity II splits off D-alanine residues from position 4 of the peptide subunits in the nascent murein. In the mutant strain activity I is reduced 10fold compared with strain K 12, whereas activity II is not affected. The two activities could be distinguished with regard to their sensitivity to D-amino acids and the beta-lactam antibiotic thienamycin.

Alanine↗
PubMed1986

LD-carboxypeptidase activity in Escherichia coli. II. Isolation, purification and characterization of the enzyme from E. coli K 12.

A LD-carboxypeptidase from Escherichia coli K 12 was isolated by Tris-EDTA treatment and purified to electrophoretic homogeneity by DEAE-cellulose chromatography. The enzyme has a molecular weight of approximately 12,000 as determined by sodium dodecyl sulfate-polyacrylamide electrophoresis and by Sephadex G-100 gel filtration. The studies of the substrate specificity of the enzyme revealed that UDP-MurNAc-tetrapeptide is a superior substrate, with a Km value of 1 X 10(-4) mol/l. The activity of the LD-carboxypeptidase was inhibited by D-amino acids and the beta-lactam antibiotic nocardicin A. Ki values of 0.3 and 43 mmol/l were determined for nocardicin A and D-homoserine, respectively. The properties of the purified enzyme correspond to activity I in ether treated cells.

Amino Acids↗