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H Zimmermann

Publications and source records attributed to H Zimmermann.

At least 127 records · Page 7Linked to original sources
PubMed1998

The impact of living on the streets on latency children's friendships.

OBJECTIVE: This is a study to evaluate friendships in latency street boys of Porto Alegre, RGS, Brazil. METHODS: A sample of 30 latency street boys was compared with a sample of 51 latency boys living with their low income families, using the Cornell Interview of Peers and Friends (CIPF). RESULTS: The two groups had a significantly different CIPF global scores, and the boys of the street group had the highest mean score. Also, boys of the street had significantly lower developmental appropriateness, self-esteem and social skills scores than boys living with a family. CONCLUSIONS: The urgent need for intervention street children, especially on boys of the street, is emphasized.

Brazil↗
PubMed1998

Evaluation of an oral pulsatile delivery system for melatonin in humans.

Using melatonin (MT) as a circadian synchroniser in humans to treat a variety of rhythm disorders, it is desirable to develop controlled-release dosage forms that deliver MT in accordance with its endogenous secretory pattern as well as preparations that release MT in a pulsatile way. In this paper we describe two oral pulsatile dosage forms containing 10 mg MT each (capsules B and C) and a fast-release form containing 5 mg MT (capsule A) studied in a randomised single-dose, threefold cross-over study in 15 healthy male volunteers. The concentrations of both MT in serum and its main metabolite 6-sulfatoxymelatonin (aMT6s) in urine were analysed by means of specific radioimmunoassays up to 10 h p.a. of the MT preparations. Mean peak concentrations of MT in serum were reached between 0.5 h and 0.75 h (Cmax[1] pmol/ml): 20.7 (A), 16.4 (B), 9.7 (C). The capsules B and C released a second MT pulse after about 3.5 h with Cmax[2] of 13.0 and 17.5 pmol/ml, respectively. Dose proportionality for the MT preparations studied was calculated by determining the AUC0-infinity (pmol/ml.h): 18.4 (A), 36.1 (B), 42.4 (C). The terminal serum half-lives of MT ranged between 0.64 and 0.84 h. The time course of the renally excreted aMT6s correlated with that of changes in MT serum concentrations.

Adult↗
PubMed1998

Pharmacokinetics of orally administered estradiol valerate. Results of a single-dose cross-over bioequivalence study in postmenopausal women.

A randomized, single-dose cross-over study in 32 postmenopausal women was performed to demonstrate bioequivalence of two estradiol valerate containing formulations (first sequence of Klimonorm as test preparation). The serum levels of estradiol, free and conjugated estrone were measured until 48 h after an oral dosage of 4 mg estradiol valerate (CAS 979-32-8). The mean AUC(0-48) of estradiol was calculated as 1006.6 +/- 479.4 h x pg x ml-1 (Test) and 1015.2 +/- 555.2 h x pg x ml-1 (Reference). The corresponding (AUC(0-48) of the active metabolite, free estrone, exceeded that of estradiol at 3578.3 h x pg x ml-1 (Test) and 3485.1 h x pg x ml-1 (Reference). Much higher was the AUC(0-48) for conjugated estrone at 132.4 h x ng x ml-1 (Test) and 133.6 h x ng x ml-1 (Reference). Mean estradiol Cmax values of 39.8 +/- 17.7 pg/ml (Test) and 42.9 +/- 21.0 pg/ml (Reference) were attained 8.2 +/- 4.5 h (Test) and 10.0 +/- 5.9 h (Reference) after the administration of 4 mg estradiol valerate. Maximal free estrone concentrations of 163 pg/ml (Test) and 174.3 pg/ml (Reference) were reached after 7.2 h (Test) and 7.5 h (Reference). Maximal conjugated estrone concentrations of 15.5 ng/ml (Test) and 16.2 ng/ml (Reference) were reached after 2.4 h (Test) and 2.0 h (Reference). The terminal elimination half-life of estradiol was calculated at 16.9 +/- 6.0 h (Test) and 15.0 +/- 4.8 h (Reference), that of free estrone at 16.3 h (Test) and 13.5 h (Reference), that of conjugated estrone at 11.8 h (Test) and 10.6 h (Reference). After logarithmic transformation, the 90% confidence intervals of the AUC(0-48) and Cmax ratios for estradiol and also for the metabolites (free and conjugated estrone) were within the acceptance ranges for bioequivalence. Therefore the test preparation and the reference preparation are bioequivalent.

Administration, Oral↗
PubMed1998

[Endoscopic surgical technique in appendectomy. Experiences and results of 950 laparoscopic appendectomies].

In a prospective study 950 appendectomies were done consecutively from May 1992 to September 1997. When indication for appendectomy was given all patients were operated on endoscopically. In 5.5% of cases had to be turned to open operation. 17 different surgeons are involved. Even the first appendectomy in adjucation of young residents was done endoscopically. 372 (39.15%) male and 578 (60.85%) female patients were operated. Average age was 25.3 years (4 to 84 years). In 11% of cases so-called chronic recurrent appenditicis as indication was accepted only after careful exclusion of other reasons for complaint. Mean duration of operation time was 44.5 min (15 to 170 min). Hospital stay was influenced subjectively 6.1 day (1 to 19 days). Examination of specimen by the pathologist shows following results: perforated appendicitis 7%; acute appendicitis 50%; chronic recurrent 33%; no pathologic changes 9%; carcinoide or oxyures 1%. The Postoperative complication rate was very small: only 2.7% (relaparotomy because of small bowel obstruction: 4, paracolic abscess after severe phlegmonic inflammation: 4, infected haematomas: 2, relaparotomy because of unobserved deverticula of Meckel with severe inflammation: 1, delayed woundhealing: 8, postoperative pain with duration long than: 24 hours: 7).

Adolescent↗
PubMed1997

Focal cerebral ischemia enhances glial expression of ecto-5'-nucleotidase.

The effect of ischemia on the reactive expression of ecto-5'-nucleotidase in rat brain was studied 6 h and 1, 2 and 7 days after permanent middle cerebral artery occlusion (MCAO). The distribution of 5'-nucleotidase in the infarcted brain was compared to markers for astrocytes (glial fibrillary acidic protein (GFAP)) and microglia (complement receptor type 3, antibody OX42) using histological staining or immunohistochemistry. 5'-Nucleotidase could be associated with reactive astrocytes by immunohistochemistry and with reactive microglia by enzyme histochemistry. In the untreated control 5'-nucleotidase was associated with astrocytes only in the hippocampus and the submeningeal space. After ischemia the enzyme was expressed on reactive astrocytes in the tissue surrounding the volume of infarction. Individual reactive astrocytes were observed 6 h after MCAO and the astrocytic expression became continuously enhanced during the following days. An enzyme histochemical analysis of 5'-nucleotidase activity revealed a postischemic increase in reaction product around the infarcted tissue. Seven days after MCAO a discrete band (0.2-0.4 mm) of reaction product characterized the rim of the infarcted area. This band of activity of 5'-nucleotidase colocalized with a band of immunoreactivity for OX42, indicative of an intense accumulation of 5'-nucleotidase expressing microglia. Our results suggest that ischemia following permanent MCAO results in an upregulation of the capacity for the hydrolysis of nucleotides within the tissue adjacent to the infarcted volume. Nucleotides released from the damaged cells can be hydrolyzed and the adenosine eventually formed may exert neuroprotective functions limiting the extent of damage.

5'-Nucleotidase↗
PubMed1997

Cell attachment and mouse virulence of echovirus 9 correlate with an RGD motif in the capsid protein VP1.

The recently analyzed sequences of the nonpathogenic prototype strain Hill and the mouse-virulent strain Barty of the human echovirus 9 differ particularly in an insertion coding for an RGD motif at the C-terminus of the capsid protein VP1 in the genome of strain Barty. To investigate molecular determinants of virulence, we generated a panel of recombinant viruses derived from cDNA clones of strains Hill and Barty. In this communication, we show that the mouse-pathogenic character of strain Barty correlates with a 310-aa segment including the RGD motif. By mutating the RGD to an RGE tripeptide, the infectivity of the resulting echovirus 9 clones for GMK cells is lost. Furthermore, we could show that synthetic peptides containing the RGD sequence influence binding of mouse-virulent echovirus 9 strains to GMK cells, whereas binding of apathogenic strains is not affected. These results suggest that the RGD motif is a significant factor affecting pathogenicity of echovirus 9 strains.

Animals↗
PubMed1997

Analysis of a cDNA encoding the major vault protein from the electric ray Discopyge ommata.

The major vault protein is the predominant constituent of vaults ubiquitous large cytosolic ribonucleoprotein particles. A cDNA clone encoding the 100-kDa major vault protein (MVP100) was isolated from an electric lobe library of Discopyge ommata. The complete nucleotide sequence was determined. Northern blot analysis revealed a 2.8-kb transcript with a high expression in neural tissue. Southern blot analysis indicates that the electric ray MVP100 is a single copy-gene with at least two introns. The primary structure of major vault proteins characterized in slime mold, ray, rat and human is evolutionary highly conserved.

Amino Acid Sequence↗
PubMed1997

New Aspects of Spin Diffusion and Cross Relaxation in Solid-State NMR

Theoretical models for motionally driven spin diffusion are compared and applied to spins S = (1/2) and S = 1. Their predictions are quantitatively corroborated by experiments on a single crystal of deuterated biphenyl. In this system, a molecular flip process drives spin diffusion and makes it strongly temperature dependent. In the second part, it is shown how spin diffusion of quadrupolar order degenerates into cross relaxation. A single crystal of partially deuterated durene provides a clear-cut example of cross relaxation in a dipolar coupled pair of spins S = 1. This observation explains why, in solids, the relaxation time of quadrupolar order, T 1Q , is often much shorter than T 1 .

Journal Article↗
PubMed1997

Dynamic Hydrogen Disorder in Solid Tropolone. A Single-Crystal NMR Study of the Hydroxyl Deuterons

The orientation and temperature dependences of the deuterium NMR spectrum and spin-lattice relaxation time of the hydroxyl deuterons in single crystals of tropolone-d 1 are reported. The results are interpreted in terms of a dynamic hydrogen disorder model in which the hydrogen nuclei move in an asymmetric double well potential. According to this model, the hydrogen-bonded dimer structure as determined by X-ray diffraction constitutes a majority species in the tropolone crystal, comprising more than 98% of the molecules at room temperature. However, there also exists a tautomeric minority species formed by a concerted back and forth shifting of the hydroxyl hydrogens (deuterons) along the hydrogen bonds to the nearby carbonyl oxygens. This process results in a modulation of the electric field gradient tensor at the site of the deuterons, thus providing an efficient relaxation mechanism. The concentration of the minority species is too low and its lifetime is too short to make its direct observation possible. Still, structural information about this species and kinetic and thermodynamic parameters of the hydrogen shift process can be derived by fitting the measured T 1 values to the above model.

Journal Article↗
PubMed1997

[Influenza surveillance in Switzerland].

The Swiss Sentinel Network (SSN) has monitored influenza activity in Switzerland since 1986. Between 2600 and 6600 cases of influenza-like-illness (ILI) are reported each influenza season by the 150-200 general practitioners, internists and paediatricians who voluntarily participate in the SSN. Based on these figures, there are an estimated 100,000 to 230,000 cases of ILI in Switzerland each year during the main influenza-season (10 week-peak-periods). Among patients over 60 years, 13% to 20% developed pneumonia and 1.3% to 2.7% had to be hospitalised. This represents an estimated 1800 hospitalisations caused by influenza for the country as a whole each year. Based on data from the Swiss Medical Statistic VESKA (H+), there are an estimated 1600 hospitalisations per year, confirming the estimation of the SSN. Collaboration with the Swiss National Center for influenza allows identifications of circulating influenza-strains and the determination of eventual deviations from the vaccine strains. The SSN has been a valuable surveillance tool during the last ten years and has provided useful data on the extent and importance of influenza in Switzerland. It therefore makes an important contribution to the elaboration of targeted and appropriate prevention measures against influenza.

Adolescent↗
PubMed1997

[Effect of cataract technique and duration of surgery on fibrin reaction after IOL implantation].

BACKGROUND: Having changed our cataract operation technique from ECCE to phacoemulsification (PE) we had the impression of less fibrinous membranes postoperatively. METHOD: To ascertain whether our impression was correct, we examined the last 2056 IOL implanted cataract patients retrospectively. RESULTS: In the 2056 cataract cases we found 152 fibrinous reactions (7.4%). We observed after ECCE (n = 586) a 12.8% rate of fibrinous membranes, after phacoemulsification (PE) with sutured 6.5-mm corneoscleral incision (n = 546) 7.0%, and after PE with clear corneal self-sealing 4.1-mm incision (n = 924) only 3.9%. In 56% of these patients we found diabetes, in 13% former uveitis with posterior synechiae, in 11% glaucoma with rigid pupil, and in 10% pseudoexfoliation syndrome. In those cases with no diabetic retinopathy but known diabetes (n = 198), we found a 27% rate of fibrin reactions following ECCE (12 mm), 12% following PE (6.5 mm) and 8% following PE (4.1 mm). In non-proliferative diabetic retinopathy (n = 80) a 32% rate of fibrinous changes was observed after ECCE, 18% after PE (6.5 mm), and 9% after PE (4.1 mm). In cases of uncomplicated ECCE (n = 341) the rate of fibrinous reactions amounted to 22.4% following prolonged procedures (> 50 min) by residents, while it was as low as 9.5% following operations of short duration (< 30 min) by experienced surgeons. Intraocular injection of tPA (25 micrograms) was the most effective treatment. CONCLUSION: The self-sealing corneal small incision cataract technique guarantees a short duration of the surgical procedure and the last fibrinous reactions.

Cataract Extraction↗
PubMed1997

An ecto-ATPase and an ecto-ATP diphosphohydrolase are expressed in rat brain.

Extracellular nucleotides acting as signaling molecules are inactivated by hydrolysis catalyzed by ecto-nucleotidases. ATP is sequentially degraded via ADP and AMP to adenosine. Enzymes that can be involved in the extracellular hydrolysis chain are ecto-ATP diphosphohydrolase (ecto-apyrase), ecto-ATPase, ecto-ADPase and 5'-nucleotidase. Mammalian ecto-ATP diphosphohydrolase is a member of a family of apyrases sharing four "apyrase conserved regions" that presumably participate in the formation of the catalytic site. We report the presence of ecto-ATP diphosphohydrolase in rat brain and the primary structure of a new mammalian member of the apyrase family. Expression in CHO cells shows that it represents an ecto-ATPase. As revealed by Northern analysis of rat tissues, the ecto-ATPase is co-expressed with ecto-ATP diphosphohydrolase in heart, kidney, spleen, thymus, lung, skeletal muscle and brain. Signals for both ecto-nucleotidases are very weak in liver. mRNAs for both proteins are present in PC12 cells, suggesting that the two nucleotidases may be co-expressed in the same neural cell. Using computer-aided sequence analysis, primary structure and membrane topography are compared with those of other members of the apyrase family.

Adenosine Triphosphatases↗
PubMed1997

Hepatic stellate cells (Ito cells) but not collagen IV may partly be responsible for lower portal pressure after reversing secondary biliary cirrhosis in the rat.

BACKGROUND/AIMS: Chronic bile duct obstruction in the rat leads to biliary cirrhosis and portal hypertension. Biliary decompression with Rouxen-Y choledocho-jejunostomy (RY) reverses most but not all of these changes. The aim of the present study was to determine whether hepatic stellate cells, as a main source of extracellular matrix proteins, participate in this process. METHODS: Sprague-Dawley rats were allocated to one of three groups: Bile duct ligation (BDL) for 3 weeks, BDL followed by RY and sham-operated animals as controls (SHAM). At the end of the experimental period, portal pressure was measured, livers subjected to random sampling and hepatocytes, bile ducts/ductules, hepatic stellate cells and collagen IV determined stereologically. Hepatic stellate cells and collagen IV were characterized immunohistochemically with an antibody against desmin and collagen IV, respectively. RESULTS: Volume fraction of hepatocytes decreased from 65.6 +/- 5.3 in sham-operated animals to 27.9 +/- 8.8% in bile duct ligated animals (p < 0.05). In contrast, volume fraction of bile ducts/ductules increased from 0.4 +/- 0.2 in sham-operated animals to 25.3 +/- 8.6% in bile duct ligated ones; similarly, hepatic stellate cells increased from 0.4 +/- 0.2 in sham-operated animals to 2.6 +/- 0.9% in bile duct ligated ones (p < 0.01) and collagen IV from 10.0 +/- 2.3 in sham-operated animals to 24.5 +/- 8.0% (p < 0.01) in bile duct ligated animals. These changes were partially reversed by Roux-en-Y choledocho-jejunostomy; hepatocytes, bile ducts/ductules, hepatic stellate cells and collagen IV averaging 54.8 +/- 13.1, 6.1 +/- 6.8, 1.6 +/- 0.6 and 14.5 +/- 3.6%, respectively (p < 0.05 RY vs. BDL). Portal pressure in sham-operated animals, bile duct ligated animals and those with a Roux-en-Y choledocho-jejunostomy averaged 13.4 +/- 0.7, 20.1 +/- 2.7 and 16.9 +/- 1.6 cm H2O, respectively, and correlated significantly with the volume fraction of hepatic stellate cells (rS = 0.96; p < 0.001) and less with collagen IV (rS = 0.61; p < 0.007). However, by stepwise regression, collagen IV did not significantly add to the ability of the equation to predict portal pressure. CONCLUSIONS: These results lend further support to the notion that hepatic stellate cells are prominently involved in fibrogenesis and in the reversibility of these changes, but hepatic stellate cells do not completely revert to normal even 4 weeks after successful decompression. Furthermore, our data suggest that hepatic stellate cells may be related to maintenance of portal hypertension.

Anastomosis, Roux-en-Y↗
PubMed1997

Are mechanisms of exocytosis neurotransmitter specific?

In their review, Langley and Grant (1997) investigate the question whether mechanisms of exocytosis are neurotransmitter specific. There is now much evidence that the mechanisms governing the exocytosis of the two principal storage organelles--granules (large dense core vesicles) and electron-lucent vesicles--differ. But much less is known concerning potential differences in the release mechanisms of electron-lucent vesicles that store different types of fast neurotransmitters or of granules in different types of neurons. It is an open question whether there is a unifying control mechanism for the exocytosis of, for example, a peptide-containing granule of a glutamatergic neuron, a chromaffin granule, a noradrenergic granule or a granule from a neurosecretory neuron in the pituitary. The small electron-lucent synaptic vesicles of various kind apparently share common molecular components of regulated release. They carry the calcium sensor synaptotagmin, small GTP-binding proteins of the rab3 group or the v-SNARE synaptobrevin. Nevertheless, there may be differences in the regulatory mechanisms. This concerns the type of calcium channel involved or the absence of some of the presynaptic molecules such as rab3a, synapsin I or the t-SNAREs SNAP-25 or syntaxin from distinct types of neurons or sensory cells.

Adenosine Triphosphate↗
PubMed1997

Dynamic phosphorus-31 spectroscopy after fructose load in experimental biliary liver cirrhosis.

RATIONALE AND OBJECTIVES: The authors investigated the usefulness of dynamic phosphorus-31 magnetic resonance (MR) spectroscopy in the assessment of hepatic function by studying the effect of a fructose load on a rat model of liver cirrhosis. METHODS: In vivo P-31 MR liver spectra of eight rats with bile duct ligature and 10 control rats were obtained every 4.6 minutes before and after intraperitoneal fructose load (10 mmol per kilogram of body weight). RESULTS: In the basal spectra of the experimental group, the phosphomonoester peak was higher than in the control group (P = .026). After the fructose load, the phosphomonoester peak increase and the inorganic phosphate peak decrease were significantly less marked in the experimental group (P = .003). There was a linear correlation between the serum level of bilirubin and the phosphomonoester increase (r = .61, P < .001). CONCLUSION: Dynamic P-31 MR spectroscopy may be useful in the assessment of hepatic function in chronic liver disease.

Analysis of Variance↗
PubMed1997

Immunocytochemical localization of synaptic proteins at vesicular organelles in PC12 cells.

The distribution of the three synaptic vesicle proteins SV2, synaptophysin and synaptotagmin, and of SNAP-25, a component of the docking and fusion complex, was investigated in PC12 cells by immunocytochemistry. Colloidal gold particle-bound secondary antibodies and a preembedding protocol were applied. Granules were labeled for SV2 and synaptotagmin but not for synaptophysin. Electron-lucent vesicles were labeled most intensively for synaptophysin but also for SV2 and to a lesser extent for synaptotagmin. The t-SNARE SNAP-25 was found at the plasma membrane but also at the surface of granules. Labeling of Golgi vesicles was observed for all antigens investigated. Also components of the endosomal pathway such as multivesicular bodies and multilamellar bodies were occasionally marked. The results suggest that the three membrane-integral synaptic vesicle proteins can have a differential distribution between electron-lucent vesicles (of which PC12 cells may possess more than one type) and granules. The membrane compartment of granules appears not to be an immediate precursor of that of electron-lucent vesicles.

Animals↗
PubMed1997

Rhodanine resistance and dependence of echovirus 12: a possible consequence of capsid flexibility.

Recombinant viruses of echovirus 12 carrying mutations of a rhodanine-resistant or -dependent variant, were investigated, and five single mutations each inducing a rhodanine-resistant or -dependent phenotype were defined. Four mutations are localized in the capsid protein VP1, and the fifth exchange is in VP4. All original and recombinant viruses were shown to be stabilized by the antiviral drug rhodanine against heat inactivation. Hence, resistant and dependent variants still seem able to bind rhodanine, and apparently none of the exchanges affects the putative drug binding site. We hypothesize that drug resistance and dependence are consequences of an increased flexibility of the virus capsid.

Amino Acid Sequence↗