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Biomedical subjects

R Wettstein

Publications and source records attributed to R Wettstein.

At least 19 recordsLinked to original sources
PubMed2006

Effective treatment of permanent tattoos with combustible particles due to blast injuries with a V-shaped device.

Permanent tattooing due to blast injuries is a rare condition. Treatment with various different methods often yields unsatisfactory results. An innovative way to remove permanent traumatic tattoos is presented. A normal curettage blade is simply compressed with a pincer in order to create the new device. This V-shaped blade was used for surgical excision of the particles. No suture material or special dressing was used. Four patients with multiple explosive tattoos on the face were treated with the V-shaped knife. Due to the ease and speed of this method up to 300 particles were removed in one session. Histological analysis of the tissue samples showed deep dermal and subcutaneous particle location. At follow-up transient hypopigmentation but only minimal scarring was seen. Patients suffered less from itching, a chief complaint preoperatively, and aesthetic appearance of the facial skin was improved. In conclusion, treatment of traumatic tattoos with the V-shaped knife is effective, results in minimal scaring and restores the natural colour of the skin because the particle is completely removed. It is a promising method for treating multiple deep skin inclusions.

Adult↗
PubMed2006

Hand rub consumption and hand hygiene compliance are not indicators of pathogen transmission in intensive care units.

The objective of this study was to investigate whether nosocomial infection (NI) rates, hand hygiene compliance rates and the amount of alcohol-based hand rub used for hand disinfection are useful indicators of pathogen transmission in intensive care units (ICUs), and whether they could be helpful in identifying infection control problems. All isolates of 10 of the most frequent pathogens from patients who were hospitalized in an ICU for >48 h were genotyped to identify transmission episodes in five ICUs. The incidence of transmission was correlated with hand hygiene compliance, hand rub consumption and NI rates. The incidence of transmission episodes varied between 2.8 and 6.8 in the five ICUs. The NI rate was 8.6-22.5 per 1000 patient-days, hand hygiene compliance was 30-47% and hand rub consumption was 57-102 L per 1000 patient-days. There was no correlation between the incidence of transmission episodes and hand rub consumption or hand hygiene compliance. The correlation between transmission rates and NI rates was 0.4 (P = 0.5), and with the exclusion of one ICU, it was 1 (P < 0.01). The incidence of NI is a relatively good indicator for the identification of pathogen transmissions, but hand rub consumption and hand hygiene compliance, at least with the relatively low level of compliance found in this study, are not indicators of pathogen transmission.

Anti-Infective Agents, Local↗
PubMed2002

Use of 2% 2-phenoxyethanol and 0.1% octenidine as antiseptic in premature newborn infants of 23-26 weeks gestation.

In preterm newborn infants, topical iodine-containing antiseptics disturb thyroid hormone regulation while alcohol-based disinfectants may cause local burns. We therefore investigated the use of an aqueous solution containing 0.1% octenidine and 2% 2-phenoxyethanol for skin disinfection during the first seven days of life in premature newborns with a gestational age <27 weeks who were consecutively admitted to our level III neonatal intensive care unit between November 1, 2000 and December 31, 2001 (N=24). In boys. (N=13) the renal excretion of absorbed 2-phenoxyethanol and its metabolite 2-phenoxyacetic acid was quantitated by high-pressure liquid chromatography. In the most immature newborn (gestational age 23 6/7 weeks), a transient erythematous reaction was observed following application of the octenidine/phenoxyethanol solution prior to umbilical vessel catheterization. No other local reactions were observed. The urinary concentration of 2-phenoxyethanol was <2 ppm in all samples, while urinary 2-phenoxyacetic acid concentrations reached 5-95 ppm (median 24 ppm). One infant had a culture-proven septicaemia (Bacillus species) during the first seven days of life. We conclude that, in contrast to alcohol-based antiseptics, an aqueous solution of 0.1% octenidine and 2-phenoxyethanol does not cause major skin damage in premature newborn infants <27 weeks' gestation. 2-Phenoxyethanol is readily absorbed by the newborn's skin but apparently undergoes extensive oxidative metabolization to 2-phenoxyacetic acid.

Anti-Infective Agents, Local↗
PubMed2002

Radical sternectomy and primary musculocutaneous flap reconstruction to control sternal osteitis.

OBJECTIVE: Sternal osteitis after median sternotomy is associated with considerable morbidity and mortality. The use of muscle and omentum flaps has been proved as valid adjunct to combat these severe infections. In this study we present our experience with a more radical approach. METHODS: Sternectomy consisted of the resection of the entire sternum, including the costochondral arches and the sternoclavicular joints, and was followed by the repair of the defect with musculocutaneous flaps without any restabilization of the thoracic wall. Thirteen patients received a vertical rectus abdominis musculocutaneous flap, 14 patients received a pedicled latissimus dorsi musculocutaneous flap, and 12 patients received a free latissimus dorsi musculocutaneous flap (total of 40 flaps in 39 patients of 66 patients who required surgical revision for sternal osteitis of 6078 total patients with sternotomies). RESULTS: Two patients died within 30 days after the operation (early mortality of 5.1%); however, they did not die of sternal infection, which was cured without any recurrence in all cases. Seventeen patients (44%) required secondary, mostly minor operations for local complications. Despite some paradoxic chest movements, the patient satisfaction rating was unanimously high at the long-term follow-up (0.4 to 8.5 years, median 2.3 years). The short- and long-term complication rates were similar in the three groups. CONCLUSION: We conclude that radical sternectomy and immediate musculocutaneous flap repair provided definitive control of sternal infection in even the most severe cases, thus reducing infection-related mortality. The trade-off was a substantial rate of local complications; however, these did not cause any relevant morbidity.

Aged↗
PubMed2002

Identification and characterization of SRSP1, a rat gene differentially expressed during spermatogenesis and coding for a serine stretch-containing protein.

By means of mRNA differential display and cDNA library screening we have characterized a novel gene of the rat that is differentially expressed during spermatogenesis. Northern blot analyses showed that its mRNA reaches the highest level during the first meiotic prophase. The transcript appears to be testis-specific as it was not detectable in any of the nine other tissues tested. The full length ORF encodes a putative phosphoprotein containing a serine stretch and a bipartite nuclear localization signal, which we call Srsp1 ("serin-rich spermatogenic protein 1"). Comparison of the cDNA from SRSP1 with genomic sequences in databases allowed us to determine the number of introns; some putative regulatory sequences are proposed. This is the first report of a gene differentially expressed during spermatogenesis that codes for a protein containing a serine stretch.

Amino Acid Sequence↗
PubMed2001

Endothelin receptor blockade improves oxygenation in contralateral TRAM flap tissue in pigs.

Partial skin and fat necrosis is the most common complication occurring in TRAM flaps. It is related to disturbances of the microcirculation and oxygenation in the contralateral part of the flap. It may be hypothesised that the development of necrosis is promoted by the vasoconstrictor endothelin, the production of which is enhanced in ischaemic flap tissues. The purpose of this study was to evaluate the effect of tezosentan, a new endothelin receptor blocker, on microcirculation and oxygenation in experimental TRAM flaps. The administration of tezosentan began preoperatively (3 mg/kg body weight) and then continued at a rate of 1.5 mg/kg/h. A TRAM flap with a skin island measuring 16 x 8 cm was raised in the middle of the epigastrium in minipigs. The flap was pedicled on the right superior epigastric vessels. Microcirculatory blood flow was measured with laser Doppler flowmetry and tissue oxygen tension was measured with a Clark-type microprobe. Dominant subcutaneous veins were cannulated in both the ipsilateral and the contralateral parts of the flap. Subdermal tissue oxygen tension in the contralateral part of the flap was significantly reduced 4h after surgery to 5 mmHg (ca. 48 mmHg in normal tissue) in the control group, but to only 12 mmHg in the group that had been administered tezosentan (P< 0.05). Furthermore, tezosentan significantly attenuated venous hypertension (14 mmHg versus 24 mmHg), as well as lactate (4.0 mmol/l versus 5.6 mmol/l) and haemoglobin (10.2 g/dl versus 11.4 g/dl) concentrations in the venous effluent of the contralateral part of the flap, although microcirculatory blood flow remained virtually unchanged. Our findings suggest that tezosentan improves oxygenation and metabolism in the jeopardised contralateral flap tissue, probably as a result of a decrease in venous vascular resistance and fluid extravasation.

Analysis of Variance↗
PubMed2000

The effect of pedicle artery vasospasm on microhemodynamics in anatomically perfused and extended skin flap tissue.

The aim of this study was to evaluate quantitatively the influence of pedicle artery vasospasm on the microcirculation in skin flaps, particularly in the jeopardized extended portions. For this purpose, the hamster island skin flap model was used, which allowed for simultaneous assessment of hemodynamics in both the pedicle artery and the microvasculature of the flap by intravital microscopy. Vasospasm was induced by applying a V3 microvascular clamp for 30 seconds. Clamping resulted in a severe vasospasm, with the artery exhibiting a diameter of 7% +/- 2% (mean +/- standard error) of its original diameter (n = 10; p < 0.01), and with a reduction of total blood flow to the flap of 11% +/- 2% (p < 0.01). Diameter and blood flow recovered gradually to baseline levels after 25 and 15 minutes respectively. During recovery from severe pedicle artery vasospasm (moderate to mild vasospasm), the arterioles in the anatomically perfused flap tissue (n = 38) showed reactive vasodilation (p < 0.01), which was absent in the extended tissue (n = 49; p < 0.01 vs. anatomic). At a pedicle artery vasospasm of 50% of the original diameter, blood flow was restored to normal levels in the anatomically perfused arterioles, but remained below baseline in the extended part (partly p < 0.05 vs. baseline and anatomic). The findings suggest that the development of ischemic necrosis in extended flap portions may be promoted by prolonged, moderate vasospasm, which is well tolerated in the anatomically perfused tissue because of its high capacity for implementing compensatory local regulatory mechanisms.

Animals↗
PubMed1996

Stage-specific gene expression during rat spermatogenesis: application of the mRNA differential display method.

Spermatogenesis is a complex differentiation process which requires the coordinate synthesis of diverse stage-specific proteins. In attempting a large-scale identification and characterization of those proteins, we have made use of the recently described mRNA differential display method (Liang and Pardee, Science 257: 967-971, 1992). This method is based on the reverse transcription of mRNAs obtained from two different cell populations (pachytene spermatocytes and spermatids in the present study) followed by a PCR reaction and comparison of the individual cDNA populations in a polyacrylamide gel system. Up to the present we have been able to identify 268 cDNA bands. Most of them (77%) are common to both cell stages. From the differentially expressed bands (23%) an ample majority was spermatid-specific (74%). According to our present results we conclude that the mRNA differential display is a promising approach for investigations on stage-specific gene expression during a differentiation process like spermatogenesis.

Animals↗
PubMed1995

Spermatocytes and round spermatids of rat testis: protein patterns.

Spermatogenesis is a process in the testis that involves meiotic cell division and spermiogenesis. The mechanisms of regulation and its associated proteins are mostly unknown. This publication shows the two-dimensional (2-D) gel electrophoresis protein map obtained from rat testis using nonlinear 3.5-10 immobilized pH gradients for the first-dimensional separation. Eighteen proteins were successfully identified in the SWISS-PROT protein database using amino acid analysis of proteins recovered from polyvinylidene difluoride (PVDF) membranes and verified for one of them by comparison with Anderson's rat liver reference map. Fourteen new polypeptides were identified and four were previously known. Two of these new proteins were closely related to the spermatogenetic process. T-complex protein 1 is expressed in large amounts in germ cells. Androgen-dependent sperm-coating glycoprotein is secreted by epididymal cells. In order to detect changes in protein expression during meiosis and spermiogenesis, spermatocytes and round spermatid cell populations were purified by centrifugal elutriation and compared. In this way several proteins not found in the spermatocyte 2-D images could be high-lighted. The sperm-coating glycoprotein was thus shown to be present in large amounts in round spermatids.

Adolescent↗
PubMed1993

Immunocytochemical localization of DNA in synaptonemal complexes of rat and mouse spermatocytes, and of chick oocytes.

The distribution of DNA in synaptonemal complexes of rat and mouse spermatocytes, and of chick oocytes was investigated by immunogold electron microscopy. Except for a few specific sites, DNA was not immunolocalized in the space between lateral elements of the complex. Some labeled fibrils connecting the lateral elements with the central element were observed associated with recombination nodules or near them. However, other labeled fibrils in the space between lateral elements did not appear to present any relationship to recombination nodules. The immunocytochemical approaches used here confirmed the presence of significant amounts of DNA in the lateral elements as previously indicated by preferential DNA staining methods. Furthermore, our findings support the view that recombination nodules are the site of chiasma formation.

Animals↗
PubMed1983

Drugs and homicide: a theory.

In this paper we report our experience with 24 cases in which there was a homicide or homicides committed in association with use of large amounts of psychoactive drugs. Many, if not most of these homicides, would not have occurred without drug effects, for frequently there was evidence of grossly illogical thinking in close temporal association with use of intoxicants and in many cases there was no previous history of violence, no evidence of premeditation, no plan to avoid arrest and little or no discernible motivation. Usually there were multiple losses or other severe stress in the lives of the persons committing the homicide in the months preceding the crime. The stress increase was accompanied by increased and extraordinary intake of psychoactive substances. We theorize that high doses of psychoactive drugs impaired severely the brain systems upon which the mental functions of reality testing and judgment depend. Drug induced impairment of reality testing and judgment is frequently uncritically equated with hallucinations, disorientation, changes in time perception or other drug induced mental phenomena. Impairment of reality testing and judgment are basic criteria for linking drug effects with the behavior of homicide in the cases reviewed.

Adult↗
PubMed1982

Comparative DNA analysis of three South American marsupials.

Published information on marsupials DNA is limited to a group of species belonging to only one genus. No previous reports have been written on South American species. In this paper we characterize the DNA of three out of the four marsupials found in Uruguay. Analytical and preparative ultracentrifugations in neutral CsCl gradients, including four intercalating agents and in Cs2SO4 gradients in presence of increasing amounts of Hg++ ion did not allow us to separate any satellite fraction. The buoyant density of the unique peak measured in CsCl gradients was in every case 1.697 g/cc with a G-C content of 37.7%. Digestion of total DNA with 11 restriction endonucleases produced a different pattern of bands for the three species, although some possible homologies could be established. Hybridization with 32P-rRNA of Southern blots of the gels containing digested DNAs demonstrated that the repeated sequences evidenced do not correspond to the ribosomal cistrons.

Animals↗
PubMed1982

Ultrastructural analysis of the X1X2X3O sex chromosome system during the spermatogenesis of Tegenaria domestica (Arachnida).

An ultrastructural study was performed on the sex chromosomes (male X1X2X3O) during the spermatogenesis of Tegenaria domestica (Arachnida, Agelenidae). This study was carried out using random and serially cut sections. During pachytene and diplotene the three X chromosomes are longitudinally paired. Each of these consists of a central core of condensed chromatin, surrounded by a field of dense chromatin projections through which the chromosomes are in contact with one another. These projections may be responsible for the recognition and pairing of the sex chromosomes and in some way participate in their non-disjunction during anaphase I. A study of the structure and behaviour of the sex chromosomes during spermatogenesis is also presented. The available information on non-synaptonemal complex-mediated chromosome pairing and a systematization of sex chromosome structure in spiders are discussed.

Animals↗
PubMed1981

The mature mesonephric nephron of the rabbit embryo. II. TEM-studies.

Transmission electron micrographs of the mesonephric nephron in 18 day rabbit embryos reveal major cytological structures reappearing in the nephron of the definitive rabbit kidney. The initial segment of the proximal tubule resembles (despite quite different cell proportions) the cell picture of the metanephric S2-segment. The changes occurring at the end of the terminal proximal segment, the decrease in cell size, flattening of the nuclei, shortening of the brush border and reduction of Golgi profiles and endocytotic organelles largely parallel those between S2 and S3. The type of increased basolateral cell face of the proximal and distal tubule cells shows only quantitative differences to their metanephric counterparts. The distal tubule, which cannot be further subdivided (except the macula densa-region) exhibits varying degrees of cell interdigitations with vertically arranged and partially arching lateral ridges. This tubule matches closely the metanephric medullary straight part of the distal tubule, so that the sequence of the first mesonephric nephron segments is similar to the metanephric ones with the exception that the thin limb of Henle is absent. The large macula densa-region is characterized by its cell height and distended infranuclear spaces. The principal cells of the collecting tubule, with a few basal infoldings and intense short lateral interlockings resemble metanephric cells of the outer medullary collecting duct. The mitochondria-rich intercalated cells occur in dark and light contrasting forms and are more frequent than was evident from our SEM-study. The homogenous cell population of the Wolffian duct is characterized by large glycogen deposits and comparatively smooth cell faces.

Animals↗
PubMed1980

The mature mesonephric nephron of the rabbit embryo. I. SEM-studies.

The luminal surface ultrastructure of the mature mesonephric nephron in 18 day rabbit embryos was studied in order to classify the nephron segments and to compare them with their metanephric counterparts. The proximal tubule has two slightly different segments. Its brush-bordered cells, with lateral ridges and basal microvilli (revealed in disjoined cells) exhibit structural principles similar to those of metanephric cells. The short distal tubule, starting with an abrupt border, cannot be subdivided. Its surface differs from one specimen to the next; the various cellular patterns are regarded as different functional states rather than evidence of a true cellular heterogeneity. Cells with leaf-like meandering borders correspond to similar metanephric cells favoring a paracellular transport mechanism. The collecting tubule shares common features with the metanephric collecting duct in spite of its different origin. Among principal cells, clearly demarcated by marginal microvillous rows and studded with sparse apical microvilli, non-ciliated and strongly bulging intercalated cells occur in small numbers. The latter have exaggerated, sometimes branched microvilli, and occasional microplicae. In the Wolffian duct, which has no metanephric counterpart, the single cilia dominate the picture of a homogeneous cell population. Apical globular protrusions of the tubular epithelia, which have been depicted in almost every paper on the mesonephros, are all fixation artefacts that can only be avoided by properly perfusing the living embryo.

Animals↗
PubMed1980

Ultrastructural characterization of the sex chromosomes during spermatogenesis of spiders having holocentric chromosomes and a long diffuse stage.

An ultrastructural study has been made of spermatogenesis in two species of primitive spiders having holocentric chromosomes (Dysdera crocata, male X0 and Sergestria florentia X1X2O). Analysis of the meiotic prophase shows a scarcity or absence of typical leptotene to pachytene stages. Only in D. crocata have synaptonemal complex (SC) remnants been seen, and these occurred in nuclei with an extreme chromatin decondensation. In both species typical early prophase stages have been replaced by nuclei lacking SC and with their chromatin almost completely decondensed, constituting a long and well-defined diffuse stage. Only nucleoli and the condensed sex chromosomes can be identified. - In S. florentina paired non-homologous sex chromosomes lack a junction lamina and thus clearly differ from the sex chromosomes of more evolved spiders with an X1X20 male sex determination mechanism. In the same species, sex chromosomes can be recognized during metaphase I due to their special structural details, while in D. crocata the X chromosome is not distinguishable from the autosomes at this stage. - The diffuse stage and particularly the structural characteristics of the sex chromosomes during meiotic prophase are reviewed and discussed in relation to the meiotic process in other arachnid goups.

Animals↗