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Biomedical subjects

P Weber

Publications and source records attributed to P Weber.

At least 55 records · Page 3Linked to original sources
PubMed2001

Vaccination rate and age of premature infants weighing <1500 g: a pilot study in north-western Switzerland.

UNLABELLED: In Switzerland, there are no special vaccination recommendations for premature and low-birthweight infants with respect to a particular target vaccination age. Incomplete and delayed vaccination bears the inherent risk of preventable infections. Therefore, the vaccination rate and age of 60 premature infants in north-western Switzerland born in 1994/95 were investigated in a retrospective case-control study. For this group of patients these are the first data ever available for this region. At the age of 4-5 y, the vaccination rates for polio and diphtheria, tetanus, pertussis (DTP acellular) as well as Haemophilus influenzae b (Hib) were similar in both preterm and full-term infants. In both groups, the fourth dose of vaccine against DTP, Hib and polio was far less frequently administered than the first three. The vaccination age in preterm infants for most vaccinations was significantly higher than in age-matched full-term controls. This was particularly obvious for the first dose of vaccine against polio and DTP. In preterm infants, the median age (5th; 95th percentile) at the date of the first polio vaccination was 131 (89; 270) d and 82 (60; 182) in full-term controls (p < 0.00001). The age difference was even larger for the first DTP vaccination (62 d, p < 0.00001). The main reasons for delayed vaccination may include insufficient information given to parents as well as prolonged hospitalization. CONCLUSION: Vaccination of preterm infants should be discussed in every discharge communication, with emphasis on vaccine administration at the appropriate chronological age.

Age Factors↗
PubMed2001

Genetic and phenotypic characterization of macrolide resistance in group A streptococci isolated from adults with pharyngo-tonsillitis in France.

Three hundred and three strains of group A streptococci (GAS) isolated from adults with pharyngitis were tested to evaluate their phenotype of resistance to macrolides-lincosamides and to search for macrolide resistance genes. MICs of clarithromycin were determined. The overall rate of resistance to both erythromycin and clarithromycin was 9.6%. Constitutive, inducible and M phenotypes of resistance were detected in 4.3, 2 and 3.3% of strains, respectively. All constitutive phenotypes harboured ermB genes, whereas inducible phenotypes had the ermTR gene and M phenotypes had the mefA gene. In France, the current resistance rate of GAS to erythromycin and clarithromycin remains low.

Adenoids↗
PubMed2001

Screening guidelines for retinopathy of prematurity: the need for revision in extremely low birth weight infants.

OBJECTIVE: To determine whether significant retinopathy of prematurity (ROP) can be detected before 31 to 33 weeks' postmenstrual age (PMA) in extremely low birth weight (ELBW) infants. METHODS: Medical records of all ELBW infants (<1000 g at birth) admitted to our regional perinatal center between April 1995 and January 1999 were reviewed retrospectively. Screening examinations for ROP were routinely performed at 4 to 6 weeks' chronological age (CA) from birth and followed at least every other week. Data were collected for infants who developed ROP. We determined the PMA at which the first screening eye examination demonstrated prethreshold disease and the subsequent examination that showed threshold disease (if it occurred). The percentages of infants who developed prethreshold ROP diagnosed at </=31 weeks' PMA and of those who progressed to threshold ROP before 34 weeks' PMA were determined. RESULTS: All 258 ELBW infants were screened for ROP. Seventy-eight infants (30%) were diagnosed with prethreshold ROP. Twenty-seven of these infants (35%) progressed to threshold ROP. Ten infants who progressed to threshold ROP were <34 weeks' PMA at the time of this diagnosis. Of these 10 infants, 3 were diagnosed at 31 weeks' PMA, 4 at 32 weeks', and 3 at 33 weeks'. CONCLUSION: More than 80% of ELBW infants who developed prethreshold disease in this cohort were </=33 weeks' PMA. The joint statement screening option of independently using 31 to 33 weeks' PMA for the first eye examination would have led to a diagnosis of threshold ROP on first examination in as many as 13% (10/78) of our patients. Early identification of prethreshold ROP is important for providing timely intervention in this rapidly progressive disease. Therefore, ELBW infants should receive initial ROP screening using the CA guideline of 4 to 6 weeks rather than the 31- to 33-week postconceptional age guideline.

Diagnostic Techniques, Ophthalmological↗
PubMed2001

Dialysis and disaster: San Francisco's dialysis community remembers the Loma Prieta earthquake. Interview by Susan L. Robertson.

Unlike many regions of the United States that live with seasonal disasters such as hurricanes, snow storms, or flooding from torrential rains, the greatest threat of natural disaster in California still comes from earthquakes (TransPacific Renal Network, 1998). This was proven on October 17, 1989 when the Loma Prieta earthquake rolled through northern California. Measured as 7.1 on the Richter scale, the quake's epicenter was located about 10 miles northeast of Santa Cruz along a segment of the San Andreas Fault near the town of Loma Prieta in the Santa Cruz Mountains. The impact, however, was felt throughout most of the northern portion of the state.

Adaptation, Psychological↗
PubMed2001

[New interventional gerontology in the geriatrization era of medicine].

The author analyzes contemporary demographic structures of the Czech population and outlines the prognosis of its future development. He draws attention to the marked ageing in the European context, analyzes its causes and deduces from this fact conclusions for clinical practice. The author draws attention to the actual needs not only of medical but also social services for senior citizens in general. With the prolongation of the mean life span and the increasing number of senior citizens (incl. those with multimorbidity) the necessity of knowledge of physicians--incl. non-geriatricians looking after senior citizens will increase. New geriatrics must be conceived as an interdiscipinary specialty frequently integrating other medical disciplines into team work. The author presents an outline on care of senior citizens in the Czech Republic and its goals. The meaning of modern geriatrics as a medical discipline is not nursing and terminal care but coping with the modified clinical picture of diseases and medical and social problems of senior citizens which frequently differ profoundly from those of the young and middle-aged generation or are not encountered in the latter groups. The final objective of new intervention gerontology are medical efforts to preserve for as long as possible self-sufficiency and independence of seniors; maximal possible efforts to restore the quality of life if it was impaired.

Aged↗
PubMed2000

Antibody repertoire development in fetal and neonatal piglets. II. Characterization of heavy chain complementarity-determining region 3 diversity in the developing fetus.

Since the actual combinatorial diversity in the V(H) repertoire in fetal piglets represents <1% of the potential in mice and humans, we wondered whether 1) complementarity-determining region 3 (CDR3) diversity was also restricted; 2) CDR3 diversity changed with fetal age; and 3) to what extent CDR3 contributed to the preimmune VDJ repertoire. CDR3 spectratyping and sequence analyses of 213 CDR3s recovered from >30 fetal animals of different ages showed that >95% of VDJ diversity resulted from junctional diversity. Unlike sheep and cattle, somatic hypermutation does not contribute to the repertoire. These studies also revealed that 1) N region additions are as extensive in VDJ rearrangements recovered at 30 days as those in late term fetuses, suggesting that TdT is fully active at the onset of VDJ rearrangement; 2) nearly 90% of all rearrangement are in-frame until late gestation; 3) the oligoclonal CDR3 spectratype of 30-day fetal liver becomes polyclonal by 50 days, while this change occurs much later in spleen; 4) there is little evidence of individual variation in CDR3 spectratype or differences in spectratype among lymphoid tissues with the exception of the thymus; and 4) there is a tendency for usage of the most J(H) proximal D(H) segment (D(H)B) to decrease in older fetuses and for the longer D(H) segment to be trimmed to the same length as the shorter D(H) when used in CDR3. These findings suggest that in the fetal piglet, highly restricted combinatorial diversity and the lack of somatic mutation are compensated by early onset of TdT activity and other mechanisms that contribute to CDR3 junctional diversity.

Animals↗
PubMed2000

Inhibition of monoamine oxidases by functionalized coumarin derivatives: biological activities, QSARs, and 3D-QSARs.

A large series of coumarin derivatives (71 compounds) were tested for their monoamine oxidase A and B (MAO-A and MAO-B) inhibitory activity. Most of the compounds acted preferentially on MAO-B with IC(50) values in the micromolar to low-nanomolar range; high inhibitory activities toward MAO-A were also measured for sulfonic acid esters. The most active compound was 7-[(3, 4-difluorobenzyl)oxy]-3,4-dimethylcoumarin, with an IC(50) value toward MAO-B of 1.14 nM. A QSAR study of 7-X-benzyloxy meta-substituted 3,4-dimethylcoumarin derivatives acting on MAO-B yielded good statistical results (q(2)() = 0.72, r(2)() = 0.86), revealing the importance of lipophilic interactions in modulating the inhibition and excluding any dependence on electronic properties. CoMFA was performed on two data sets of MAO-A and MAO-B inhibitors. The GOLPE procedure, with variable selection criteria, was applied to improve the predictivity of the models and to facilitate the graphical interpretation of results.

Animals↗
PubMed2000

Modulation of antigen trafficking to MHC class II-positive late endosomes of enterocytes.

BACKGROUND & AIMS: Oral tolerance is recognized as a central immunoregulatory phenomenon. The mechanisms of its induction remain unclear, and the role of the intestinal epithelial cells that are able to present antigens to T lymphocytes is poorly understood. In this report, we analyze under in vivo conditions the intracellular targeting of mucosally administered ovalbumin (OVA) to major histocompatibility complex (MHC) class II antigen containing compartments of enterocytes and compare these pathways between BALB/c and SCID mice, the latter being unable to generate a transferable tolerogenic moiety after a feed of OVA. METHODS: OVA, lysosome-associated membrane proteins (LAMP-1), and MHC class II antigens were localized in jejunal biopsy specimens of BALB/c and SCID mice at 0, 5, 10, 20, 40, 60, and 120 minutes after a single feed with OVA by fluorescence and electron microscopy. RESULTS: Ten minutes after oral administration, OVA was transported to the proximity of MHC class II antigens within LAMP-1-positive vacuoles and to the basolateral membrane of enterocytes from BALB/c strain mice. However, in SCID mice, OVA reached the paracellular spaces during the same time period through LAMP-1-negative vacuoles of enterocytes, which lacked MHC class II antigens. CONCLUSIONS: Orally administered OVA is rapidly targeted to late endosomes containing LAMP-1 and MHC class II antigens in enterocytes of BALB/c mice but not in SCID mice bred on a BALB/c background. We suggest that this targeting process within the enterocytes is one of the requirements for the induction of oral tolerance.

Animals↗
PubMed2000

Porcine IgA allotypes are not equally transcribed or expressed in heterozygous swine.

The prediction of 1:1 expression of constant region allotypes in heterozygous animals assumes that productive VDJ rearrangements occur at random between chromosomes, switch recombination is random, there is no allele-related defect in switching and there is no selection for a B-cell receptor bearing a certain constant region allotype. In data reported here, this prediction was often not fulfilled for the transcripts encoding the IgAa and IgAb alleles of porcine IgA including those from late term fetal piglets that are not in contact with environmental antigens or maternal regulatory factors. In the spleen, thymus, mesenteric lymph node (MLN), ileal Peyer patches, parotid gland and PBLs of 5-week-old conventionally-reared Duroc pigs, ratios of IgAa to IgAb transcripts as high as 4:1 were observed. Since White Cross animals had significantly higher levels of IgAb than IgAa (some >3-fold), a allele-linked switch defect cannot explain the deviation from the expected 1:1 ratio. When the IgAa:IgAb ratios in older Durocs and those reared at a different site were studied, no evidence for breed dependence of differential transcription was found. Total serum IgA levels paralleled total transcript levels in PBLs while particularly in White Cross animals, the IgAa:IgAb ratio in serum was higher in many animals than the IgAa:IgAb transcript ratio in their PBLs. We conclude that deviations from the expected 1:1 ratio of allotype transcripts and secreted IgA in young pigs is normal and deviations from this ratio also occur during fetal life in the absence of environmental antigens and maternal regulatory factors. We speculate that postnatal deviations result from: (A) exposure to environmental antigens that selectively expand B-cells expressing V(H) gene alleles linked to either IgAa or IgAb or (B) some form of colostrum-dependent regulation. Pre-natal regulation may depend on the selection of B-cells bearing certain V(H) or C(H) encoded BCRs by stromal ligands such as fetal B-cell superantigens.

Animals↗
PubMed2000

Antibody repertoire development in fetal and newborn piglets, III. Colonization of the gastrointestinal tract selectively diversifies the preimmune repertoire in mucosal lymphoid tissues.

Changes in the VH-region repertoire of isolator piglets reared for 6 weeks under germ-free (GF) conditions and those colonized (COL) with a defined exclusion flora on the 1st day of life were compared. Although serum immunoglobulin levels were 20-100-fold higher in COL piglets than GF piglets, an analysis of peripheral blood B cells (PBBs) indicated that: GF and COL piglets used the same four VH genes and two DH segments during the 6-week period; proportional usage of VH genes and DH segments was the same as in fetal animals; and VH and DH usage did not differ between COL and GF animals. This pattern differed from the PBBs from 6-week-old conventional (CONV) piglets. When the sequences of 73 splenic CDR3 segments were analysed, DH usage and mutation frequency were the same in sequences from both 6-week-old GF and COL piglets; mutations were infrequent and occurred with the same frequency as in 110-day fetal spleen. However, the median CDR3 length in COL piglets was shifted upward due to 3' DH N-nucleotide additions. Neither COL nor GF animals made specific serum antibodies to phosphoryl choline given parenterally on a T-cell dependent carrier. In contrast to the near absence of a colonization effect in PBBs and splenic DNA, rearranged variable heavy-chain gene segments (VDJs) recovered from the DNA of mucosal lymphoid tissues of COL piglets showed pronounced differences from those recovered from GF animals in usage of DHA-, DHB-and VHB- and in the frequency of point mutation. The mucosal VDJ transcripts and those from the spleen were similarly affected by colonization. This effect on mucosal lymphoid tissue was consistent with the five-fold selective increase in serum immunoglobulin A (IgA) levels relative to IgM and IgG. Comparison of IgM and IgA transcripts from mucosal tissues suggested that IgA and IgM clones diversify in parallel. Our findings are the first to show that colonization of the gastrointestinal tract of offspring separated from their mothers, differs from 'conventionalized' GF animals in that colonization preferentially influences diversification and expansion of the preimmune IgM and IgA repertoire in mucosal lymphoid tissues but not in PBBs and seldom/modestly in VDJs from splenic DNA.

ATP-Binding Cassette Transporters↗
PubMed2000

The liposuction apparatus "suspension device": hi-plane liposculpture.

BACKGROUND: The improvement of liposuction equipment and techniques has resulted in a cumbersome operating room array of aspirator hoses, irrigation/infiltration tubing, and the insulated command and control wiring of current ultrasonic or power liposuction devices. This situation is further complicated by the presence of a second surgeon, the concomitant use of additional traditional or ultrasonic cannulas, and the suction hose of a second aspirator. OBJECTIVE: To solve the problems of sterility and operating room organization, the authors describe a simple, releasable suspension design. METHOD: This apparatus can be temporarily or permanently installed in minutes and is easily maintained to control numerous sterile hoses and wires required for certain liposuction procedures. RESULTS: This suspension method appeared to enhance the efficiency and ease of use by single and dual surgeons during cases utilizing ultrasonic and nonultrasonic cannulas. The time savings and ease of use was most noticeable in cases of dual surgeons using both ultrasonic and nonultrasonic systems simultaneously. In addition, surgical personnel were freed for other tasks. Single-surgeon, traditional liposuction was less notably facilitated in terms of speed and fewer personnel. However, wiring and tubing control is facilitated in any case. CONCLUSION: A simple liposuction suspension system facilitates the liposuction procedure to varying degrees depending upon the number of surgeons and devices in simultaneous use.

Humans↗
PubMed2000

Triglyceride-lowering effect of omega-3 LC-polyunsaturated fatty acids--a review.

There is increasing evidence that serum triglycerides are a significant and independent risk factor for CVD. The aim of this report is to review recent literature pertinent to the triglyceride-lowering effect of omega-3 long chain polyunsaturated fatty acids (LC-PUFA). Animal data are not considered because they are difficult to extrapolate to the human situation. A large body of evidence derived from epidemiological studies and clinical trials has consistently demonstrated that this effect is dose-dependent and can be achieved by diet. The smallest amount of omega-3 LC-PUFA needed to significantly lower serum triglycerides appears to be approximately 1 g/day as provided by a fish diet. Use of fish oil administering as little as 0.21 g EPA and 0.12 g DHA per day significantly lowered serum triglycerides in hyperlipidemics. In normolipidemics, a daily intake of 0.17 g EPA and 0.11 g DHA, given as a fish oil supplement, induced a non-significant reduction of 22%. These findings must be considered as preliminary and warrant further research. Intake of omega-3 LC-PUFA is frequently reported to modestly increase LDL cholesterol. However, in normo- or slightly hyperlipidemic individuals who received omega-3 LC-PUFA for 4 months or longer, changes of LDL cholesterol were not significantly different from a placebo group. Both EPA and DHA lower serum triglycerides, but they may have a differential effect on lipoproteins. Intake of omega-3 LC-PUFA in the amount mentioned above is safe.

Cardiovascular Diseases↗
PubMed2000

Switzerland: new medical informatics curriculum.

Swiss Society for Medical Informatics (SSMI) started to build a postgraduate curriculum in medical informatics a year ago. The aim is to build a curriculum with different modules allowing the healthcare professionals to follow individual path in order to fulfill their objectives. The professionals who could benefit from the curriculum are physicians, nurses, medical assistants, computer specialists in the healthcare domain. Different levels of certificates or diplomas will be given depending on the number of modules taken and the professional background. Modules can be taken in different ways: universities, hospitals, distance learning.... The kickoff meeting for the leading group of this curriculum chaired by Dr Denz from Zurich was held on June 5 and 6 1998 was Swiss Nursing informatics group is active in this field. Working Group 5 (WG5) "Nursing Informatics in Europe" is supporting countries efforts in building nursing informatics curriculum. Promoting links between specialists in this domain in different countries. Selecting relevant Websites to be used. Disseminating information to country members of WG5.

Curriculum↗
PubMed2000

Twenty-four hour intraesophageal pH monitoring in children and adolescents with scleroderma and mixed connective tissue disease.

OBJECTIVE: To investigate esophageal dysmotility and gastroesophageal reflux, which are important, but often occult features of gastrointestinal (GI) involvement in children and adolescents with mixed connective tissue disease (MCTD) and scleroderma. METHODS: We carried out intraesophageal 24 h pH monitoring of 14 patients with scleroderma and MCTD. RESULTS: We observed an elevated reflux index in 64% of the patients. An increased number of reflux events was found in 85%. Reflux events > 5 min were noted in 50% of the patients, which is indicative of possible development of esophagitis. Only 3 patients presented clinical symptoms. Four of 5 patients with localized scleroderma revealed a pathological reflux index. We found no relationship between gastroesophageal reflux, age of patients, duration of disease, and Raynaud's phenomenon. CONCLUSION: GI involvement in children with scleroderma or MCTD is more frequent than clinical symptoms indicate. An active diagnostic investigation for GI dysmotility and gastroesophageal reflux is necessary to detect these complications.

Adolescent↗
PubMed1999

Mice deficient for tenascin-R display alterations of the extracellular matrix and decreased axonal conduction velocities in the CNS.

Tenascin-R (TN-R), an extracellular matrix glycoprotein of the CNS, localizes to nodes of Ranvier and perineuronal nets and interacts in vitro with other extracellular matrix components and recognition molecules of the immunoglobulin superfamily. To characterize the functional roles of TN-R in vivo, we have generated mice deficient for TN-R by homologous recombination using embryonic stem cells. TN-R-deficient mice are viable and fertile. The anatomy of all major brain areas and the formation and structure of myelin appear normal. However, immunostaining for the chondroitin sulfate proteoglycan phosphacan, a high-affinity ligand for TN-R, is weak and diffuse in the mutant when compared with wild-type mice. Compound action potential recordings from optic nerves of mutant mice show a significant decrease in conduction velocity as compared with controls. However, at nodes of Ranvier there is no apparent change in expression and distribution of Na+ channels, which are thought to bind to TN-R via their beta2 subunit. The distribution of carbohydrate epitopes of perineuronal nets recognized by the lectin Wisteria floribunda or antibodies to the HNK-1 carbohydrate on somata and dendrites of cortical and hippocampal interneurons is abnormal. These observations indicate an essential role for TN-R in the formation of perineuronal nets and in normal conduction velocity of optic nerve.

Animals↗
PubMed1999

Immunohistochemical localization of 5-oxo-L-prolinase, an enzyme of the gamma-glutamyl cycle, in porcine brain microvessels.

The immunohistochemical analysis of the distribution of 5-oxo-L-prolinase in porcine brain at the light microscopic level was performed with an antibody raised against the enzyme purified from pig kidney. The present study reveals the specific expression of 5-oxo-L-prolinase in brain capillaries with an average diameter of 4.1+/-0.9 microm, while larger blood vessels remain unstained. Porcine kidney and skeletal muscle show no endothelial-specific staining with the antibody. In some cases, the asymmetrical staining pattern in cross and longitudinal sections of brain microvessels indicate endothelial- but also pericyte-specific expression.

Animals↗
PubMed1999

Kinetic parameters and tissue distribution of 5-oxo-L-prolinase determined by a fluorimetric assay.

5-Oxo-L-prolinase (5-OPase) catalyses the hydrolysis of 5-oxo-L-proline to glutamate with concomitant stoichiometric cleavage of ATP to ADP, a reaction which is known to be part of the gamma-glutamyl cycle-an interrelated series of reactions involved in the synthesis and metabolism of glutathione. As recent studies indicate, this cyclic pathway plays a crucial role in the regulation of amino acid transport. Apparently, the intermediate product 5-oxo-L-proline functions as a second messenger molecule that upregulates the activity of certain amino acid transport systems. Thus, the degradation of 5-oxo-L-proline by 5-OPase leads to the downregulation of this stimulus. In this study, a new sensitive fluorimetric assay for 5-OPase activity was established which is based on the derivatization of glutamate with o-phthaldialdehyde in the presence of thiols and subsequent separation of the products by HPLC. The method is suitable for the screening of chromatography fractions as well as for the determination of the kinetic parameters Km and Vmax of purified 5-OPase. Additionally, it can be used for the measurement of enzyme activity in crude cell extracts and evaluation of tissue distribution.

Amidohydrolases↗