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Biomedical subjects

B Roth

Publications and source records attributed to B Roth.

At least 109 records · Page 6Linked to original sources
PubMed1993

Late developmental changes of the innervation densities of the myelinated fibres and the outer hair cell efferent fibres in the rat cochlea.

The baso-apical distributions of the myelinated nerve fibres (representative for the inner hair cell afferent fibres) and the outer hair cell efferent fibres were studied during postnatal development of the rat cochlea. The myelinated fibres were counted in the primary osseos spiral lamina from semi-thin sections. The outer hair cell efferent fibres were counted in the tunnel of Corti by means of ultra-thin sections. The developmental changes of the myelinated fibres were investigated between 8 and 60 days after birth (DAB); those of the outer hair cell efferent fibres between 20 and 30 DAB. Between 12 DAB (onset of hearing) and 20 DAB the baso-apical distribution of the myelinated fibres does not change. Striking maturational changes occur later after the onset of hearing, between 20 and 30 DAB. The innervation density of the myelinated fibres increases in the lower middle region of the cochlea. In this region a maximum of innervation density appears. The efferent fibres to the outer hair cells show at 20 DAB a maximum of innervation density in the middle of the cochlea but between 20 and 30 DAB, the fibre density decreases in this region. During the same period the maximum of innervation density shifts towards the base. The change in the innervation densities of the myelinated fibres and the outer hair cell efferent fibres occurs late in development, after the onset of hearing, and after the organ of Corti shows an adult-like appearance.

Animals↗
PubMed1993

Possible role of short-term parenteral nutrition with fat emulsions for development of haemophagocytosis with multiple organ failure in a patient with traumatic brain injury.

We describe a case of life-threatening haemophagocytosis after a short term nutrition with fat emulsion in a 21-year-old woman who sustained an isolated traumatic brain injury. Hypertriglyceridemia and "creaming plasma" were observed after a three-day period of parenteral fat nutrition (Intralipid 20%). She also developed rash, high fever (40-41 degrees C), hypertension, raised intracranial pressure, hepatic and renal failure, haemolysis, marked thrombocyto- and leucopenia, coagulation disorder and pulmonary failure. These symptoms, together with a typical bone marrow smear, indicated haemophagocytosis with hyperactivation of the monocyte-macrophage system. We suggest that the hyperactivation was an effect of fat retention or agglutination of the fat particles; the initial triggering mechanism may emanate from the brain damage by hypercytokinaemia. The steroid treatment given most likely contributed to the successful outcome, as indicated by the stepwise improvement related in time to the steroid infusions.

Adult↗
PubMed1993

Holocarboxylase synthetase deficiency: early diagnosis and management of a new case.

We present a new case of holocarboxylase synthetase (HCS) deficiency, a rare autosomal recessive metabolic disorder, causing the "early-onset" form of multiple carboxylase deficiency. The patient was born at term of healthy consanguineous parents after an uncomplicated pregnancy. On the 2nd day of life she refused oral feeding, became tachydyspnoeic and showed excessive weight loss. Laboratory studies showed metabolic acidosis, marked lactic acidaemia, hyperammonaemia and increased urinary excretion of 3-hydroxyisovaleric acid, 3-methylcrotonylglycine, 3-hydroxpropionic acid and methylcitric acid. Peritoneal dialysis combined with oral supplementation of biotin (10 mg/day) started on the 3rd day of life resulted in rapid clinical recovery and normalisation of biochemical parameters. HCS deficiency was established in lymphocytes and skin fibroblasts. The activities of all biotin-dependent carboxylases were severely decreased in fibroblasts grown in medium with moderate biotin concentration (10(-8) mol/l) but normal in a high biotin medium (10(-5) mol/l). Mitochondrial carboxylase activities in lymphocytes were 23%-29% of mean normal during therapy with 20 mg of biotin/day, with the higher dose of 40 mg/day they were within (3-methylcrotoryl-CoA carboxylase, pyruvate carboxylase) or slightly below (propionyl-CoA carboxylase) the normal range. At the age of 3 years the patient's physical and psychomotor development are normal. Early biotin supplementation should be considered in newborns with lactic acidosis and organoaciduria until a final diagnosis has been established. Furthermore, the required individual dose of biotin has to be carefully evaluated biochemically for the individual patient.

Biotin↗
PubMed1993

Airway endoscopy in the diagnosis and treatment of bacterial tracheitis in children.

Children with bacterial tracheitis present with the symptoms of viral laryngotracheobronchitis or epiglottitis, but do not respond to appropriate therapy for these diseases and frequently develop acute respiratory decompensation. Since the treatment and outcome of bacterial tracheitis differ so much from those of viral laryngotracheobronchitis and epiglottitis, prompt and accurate diagnosis is essential. The aim of this study was to evaluate the significance of different diagnostic characteristics in a group of eleven patients and to compare the results to those recently reported in the pediatric and otorhinolaryngologic literature. The present study suggests that reliable predictive factors do not exist for bacterial tracheitis. No single clinical, radiological or laboratory feature was a reliable diagnostic predictor for bacterial tracheitis, nor was it any combination of these features. The only diagnostic procedure to distinguish bacterial tracheitis accurately and promptly from other forms of acute obstructive upper airway diseases was direct laryngo-tracheo-bronchoscopy. Following endoscopic removal of all tracheal secretions and pulmonary toilet, nasotracheal intubation provides sufficient airway maintenance and obviates the need for tracheostomy. Endoscopy is thus diagnostic and therapeutic at the same time. If bacterial tracheitis is suspected a direct laryngoscopy and rigid tracheobronchoscopy should be performed under general anesthesia, as prompt diagnosis and adequate treatment are essential to survival. The cultures of the purulent tracheal secretions frequently revealed Staphylococcus aureus in combination with various pathogens, particularly the involvement of Pseudomonas aeruginosa was noted in two patients. Our data imply a susceptibility of children with Down's syndrome or immunodeficiency to bacterial tracheitis.

Acute Disease↗
PubMed1993

Fertility awareness as a component of sexuality education. Preliminary research findings with adolescents.

Fertility awareness refers to the observation and interpretation of cervical mucus, often called vaginal discharge. A woman's cervical-mucus pattern indicates the time of ovulation and differentiates the fertile and infertile phases of the menstrual cycle from each other. Fertility awareness enables a woman to know when pregnancy can and cannot occur on a daily basis during each menstrual cycle. There has been, to date, almost no exploration of the appropriateness of fertility-awareness instruction for adolescents. A review of the literature on adolescent cognitive development, sexual activity, knowledge of fertility and contraceptive risk-taking behavior is presented. Based on the literature review, a theoretical rationale for fertility-awareness instruction as a unique sex-education curriculum for adolescents is proposed. The content and teaching techniques of a fertility-awareness presentation for teenagers is described. Directions for future research in fertility-awareness instruction for teenagers, and the need for long-term follow-up to assess the effects of such education on teenagers' sexual activity and contraceptive use are discussed.

Adolescent↗
PubMed1993

Expression of the two maize TATA binding protein genes and function of the encoded TBP proteins by complementation in yeast.

A single gene encodes the TATA binding protein (TBP) in yeasts and animals. Although two TBP-encoding genes (Tbp) previously were isolated from both Arabidopsis and maize, the expression and in vivo function of the encoded plant TBPs were not investigated. Here, we report that the two highly conserved maize Tbp genes are unlinked and reside within larger, ancestrally duplicated segments in the genome. We find quantitative differences in Tbp1 versus Tbp2 transcript accumulation in some maize tissues. These nonidentical expression patterns may indicate differences in the tissue-specific regulation of these genes, which might allow the two encoded maize TBP isoforms to perform nonoverlapping functions in the plant. In addition, we show that the maize TBP products, unlike animal TBPs, are functionally interchangeable with yeast TBP for conferring yeast cell viability. This is a conclusive demonstration of in vivo activity for a nonyeast TBP protein, and these complementation results point to particular amino acids in TBP that are likely to influence species-specific protein interactions.

Amino Acid Sequence↗
PubMed1992

Postnatal development of the rat organ of Corti. I. General morphology, basilar membrane, tectorial membrane and border cells.

The development of the rat organ of Corti was studied during the first postnatal weeks. The temporal and the spatial patterns of cochlear development were investigated between 4 and 24 days after birth by means of semi-thin sections at approx. ten equidistant positions along the entire cochlear duct. At all examined positions width, thickness and cross sectional area of basilar membrane, cross-sectional area of tectorial membrane, of cells of Hensen, Claudius and Boettcher and of the organ of Corti were quantitatively analyzed. The most conspicuous maturational changes occur between 8 and 12 days after birth. These are the detachment of the tectorial membrane, the first appearance of filaments within the basilar membrane, the formation of the tunnel of Corti and the opening of the inner spiral sulcus. Quantitative analysis revealed that structures of a given position along the cochlear duct do not develop synchronously. Width of the basilar membrane and cross-sectional area of the tectorial membrane are already mature at the onset of hearing (10-12 days after birth). Length, thickness and cross-sectional area of the basilar membrane as well as cross-sectional area of the organ of Corti and of the cells of Hensen, Claudius and Boettcher still develop after the onset of hearing (up to 20-24 days after birth). We suggest that basic cochlear function is established by structures which are mature before the onset of hearing. Cochlear structures which develop after the onset of hearing might be involved in this improvement during this period.

Animals↗
PubMed1992

Postnatal development of the rat organ of Corti. II. Hair cell receptors and their supporting elements.

The development of cochlear receptor cells and their supporting elements was studied by means of semi-thin and ultra-thin sections during the first postnatal weeks in the rat. The temporal and spatial patterns of the receptor cell development were investigated between the 4th and 24th days after birth. At approx. ten equidistant positions along the entire cochlear duct length of inner and outer hair cells, width of outer hair cell triad and stereocilia-length of the outer hair cells were quantitatively analyzed. Striking maturational changes take place before the 12th day after birth, that is, when the onset of hearing occurs. These changes are the formation of the tunnel of Corti, of the Nuel spaces, the appearance of filaments within the supporting elements and the change in cell shape of the hair cells. Between 4 days and 20 days after birth the maturation of outer hair cells is characterized by a decrease of organelles in the cytoplasm and establishment of the subsurface cistern. The quantitative analysis revealed a unique developmental pattern of the length of the outer hair cells, the width of the outer hair cell triad and the stereocilia length of the outer hair cells. Shortly after birth these structures have an almost constant size along the whole cochlear duct, but with increasing age the structures shorten at the cochlear base and enlarge at the apex. This pattern results in the establishment of a baso-apical gradient of the above mentioned structures. We assume that this baso-apical gradient is of central importance for the frequency representation.

Animals↗
PubMed1992

Cerebral reperfusion in brain death of a newborn. Case report.

A case of "sudden infant death" after 15 minutes of successful resuscitation of cardiovascular function is presented. While apnoic cranial nerve areflexia and electrocerebral silence persisted, angiography and transcranial Doppler sonography demonstrated nearly normal cerebral perfusion, which even increased day by day inspite of the persistence of other signs of brain death. The phenomenon "cerebral reperfusion" is concluded to be compatible with the diagnosis of brain death.

Blood Flow Velocity↗
PubMed1992

Ketamine and midazolam decrease cerebral blood flow and consequently their own rate of transport to the brain: an application of mass balance pharmacokinetics with a changing regional blood flow.

Mass balance pharmacokinetics, with simultaneous blood sampling from an artery and the internal jugular vein, was used to characterize the cerebral uptake of ketamine, norketamine, and midazolam in normoventilated pigs. Intravenous injections of ketamine or midazolam decreased the cerebral blood flow (CBF) by one third, as measured by intermittent 133Xe washout. By means of pharmacodynamic models, the effects on the CBF could be predicted from the arterial drug concentrations. The high-resolution CBF vs. time curves thus generated allowed the calculation of cerebral drug levels from arterio-venous concentration gradients in spite of a continuously changing regional blood flow. By their effects on the CBF, ketamine and midazolam decrease their own rate of transport to the brain, the immediate 30-35% drops in CBF giving similar reductions in initial net influx of drug. Physiological pharmacokinetic models assuming a constant regional blood flow are therefore not appropriate. Under clinical conditions, the CBF is determined mainly by the effects of the anesthetics and by the arterial CO2 tension. CBF changes in either direction influence the transport of drugs to the brain and may consequently result in impaired or exaggerated drug effects.

Animals↗
PubMed1992

Application of the polymerase chain reaction in the diagnosis of pulmonary toxoplasmosis in immunocompromised patients.

Bronchoalveolar lavage (BAL) fluid from 47 immunocompromised patients (26 with AIDS and 21 patients on immunosuppressive therapy) was analysed for the presence of Toxoplasma gondii DNA by means of the polymerase chain reaction (PCR). Specific target DNA derived from the B1 and P30 gene of Toxoplasma gondii was detected in BAL fluids from three patients with AIDS (6.4%). Pneumonia as the presenting feature of disseminated toxoplasmosis was confirmed by both clinical findings and by detection of Toxoplasma gondii DNA in blood obtained from two patients. The findings indicate that PCR has potential value in the detection of Toxoplasma gondii as an etiologic agent of atypical pneumonia in immunocompromised patients.

Animals↗
PubMed1992

Calcium homeostasis and hypercalciuria in hyperprostaglandin E syndrome.

Children with hyperprostaglandin E syndrome, a neonatal variant of Bartter syndrome with enhanced renal and systemic formation of prostaglandin E2, have hypercalciuria, nephrocalcinosis, and osteopenia. Because prostaglandin E2 affects tubular calcium handling, stimulates the formation of calcitriol in vitro, and has osteolytic activity, we studied calcium homeostasis and the influence of prostaglandin E2 formation on hypercalciuria in nine patients with hyperprostaglandin E syndrome during long-term indomethacin treatment and after its withdrawal. Suppression of prostaglandin E2 formation by indomethacin resulted in improvement of biochemical and clinical features of hyperprostaglandin E syndrome. However, hypercalciuria, osteopenia, and nephrocalcinosis did not completely resolve. Despite a low calcium diet, daily urinary calcium excretion was enhanced during and after withdrawal of indomethacin treatment (median 6.3, range 5.3 to 14, and median 9.4, range 4.4 to 38 mg/kg per day, respectively). Daily urinary calcium excretion was greater after withdrawal than during indomethacin treatment. Urinary calcium excretion was not correlated with urinary prostaglandin E2 excretion. Plasma levels of intact parathyroid hormone (median 11, range 6.8 to 12 pmol/L) and calcitriol (median 157, range 108 to 236 pg/ml) were elevated during indomethacin treatment and decreased after withdrawal of indomethacin. These data suggest that hypercalciuria in hyperprostaglandin E syndrome is mainly due to a renal leak of calcium, which is caused by enhanced renal formation of prostaglandin E2 and a tubular defect not related to prostaglandin E2 formation. There is no evidence for prostaglandin-stimulated calcitriol formation. Decreasing plasma levels of parathyroid hormone in the presence of renal calcium losses after withdrawal of indomethacin treatment may be due to a bone resorption process caused by systemic prostaglandin formation; the process may contribute to hypercalciuria in the patient not receiving indomethacin.

Bone Diseases, Metabolic↗
PubMed1992

High-dose intravenous immune globulin therapy for hyperbilirubinemia caused by Rh hemolytic disease.

We conducted a multicenter controlled trial to test the hypothesis that high-dose intravenous immune globulin (HDivIG) therapy can modulate bilirubin production and reduce the frequency of exchange transfusions in newborn infants with Rh hemolytic disease. Thirty-four patients with Rh incompatibility proved by positive direct antiglobulin test (Coombs test) results were randomly assigned to receive conventional treatment including phototherapy, with or without additional HDivIG therapy at 500 mg/kg given for a 2-hour period as soon as the diagnosis was established. Exchange transfusions were performed if serum bilirubin concentrations exceeded the modified curves of Polácek by more than 2 mg/dl. Two patients were excluded because of protocol violations. The results in 32 infants were analyzed. In the HDivIG group, 2 (12.5%) of 16 children required exchange transfusions, whereas it became necessary in 11 (69%) of 16 children in the control group (p less than 0.005). Bilirubin levels in the HDivIG group were lower despite reduced frequency of exchange transfusions. No side effects of HDivIG treatment were observed. We conclude that HDivIG therapy by a yet unknown mechanism reduces serum bilirubin levels and the need for blood exchange transfusions in children with Rh hemolytic disease.

Anemia↗
PubMed1991

ChAT-like immunoreactivity of olivocochlear fibres on rat outer hair cells during the postnatal development.

Several studies present a great deal of information about putative efferent neurotransmitters and their distribution in the adult and developing cochlea. Anatomical mapping of outer hair cell efferent fibres during ontogeny is still not available. Using quantitative electron microscopy in combination with immunocytochemistry, the distribution of ChAT-like immunoreactivity in the developing rat was investigated. Adult-like immunoreactivity in the whole cochlea is first observed in 30-day-old rats. We localized the adult-like immunoreactivity in all efferent fibres and synapses of the outer hair cells along the entire cochlear duct. An adult-like reaction in the whole cochlea could be observed on the 25th day after birth in two out of three cases. On the 20th postnatal day, no adult-like ChAT immunoreactivity was found, with the exception of one case where labelling was seen in the basal region only. The adult-like ChAT immunoreactivity on the 30th day, 2-3 weeks after the onset of hearing, is the latest maturation of all features of the organ of Corti so far investigated. Synaptogenesis of the outer hair cell efferents reaches an adult-like appearance already on the 16th day after birth.

Animals↗
PubMed1991

Anatomical mapping of choline acetyltransferase (ChAT)-like and glutamate decarboxylase (GAD)-like immunoreactivity in outer hair cell efferents in adult rats.

The distribution of choline acetyltransferase (ChAT)-like and glutamate decarboxylase (GAD)-like immunoreactivity in the cochleae of 15 adult Wistar white rats was investigated using the peroxidase-antiperoxidase (PAP) technique. A monoclonal antibody to ChAT and a polyclonal antiserum to GAD were used. Immunoreaction was investigated quantitatively, in the electron microscope, on tangential sections of the tunnel of Corti and the rows of outer hair cells. ChAT-like and GAD-like immunoreactivity was found in all efferent nerve fibres in the tunnel of Corti and in all efferent synapses on the outer hair cells. A coexistence of ChAT and GAD in the efferent system to the outer hair cells of the rat is therefore assumed.

Age Factors↗
PubMed1991

Clinical experience with continuous intravenous sedation using midazolam and fentanyl in the paediatric intensive care unit.

Twenty-four patients in a paediatric intensive care unit mostly undergoing cardiac surgery, received a midazolam dosage between 50-400 micrograms/kg per hour as a continuous intravenous infusion partly in combination with fentanyl [0,5-2,5 micrograms/kg per hour] for analgesia and sedation. The mean duration of midazolam infusion was 11.6 days (range 38 h-40 days). Blood samples for the HPLC assay of serum midazolam concentration were taken and the clearance estimated. The efficiency of sedation in correlation to the midazolam concentration was evaluated by a clinical sedation score. Serum midazolam concentrations between 100-400 micrograms/l were sufficient for sedation. Dosage had to be increased during therapy according to an increased midazolam clearance. The evaluation of the sedation score showed that sedation of artificially ventilated infants and young children can be established by continuous intravenous infusion of midazolam.

Child, Preschool↗