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Biomedical subjects

J Bauer

Publications and source records attributed to J Bauer.

At least 73 records · Page 4Linked to original sources
PubMed2001

Effect of caffeine on oxygen consumption and metabolic rate in very low birth weight infants with idiopathic apnea.

OBJECTIVE: Methylxanthines are among the most commonly prescribed drugs in neonatal intensive care. This study evaluates the effect of caffeine on oxygen consumption and metabolic rate in premature infants with idiopathic apnea. METHODS: Eighteen preterm infants at gestational ages from 28 to 33 weeks and birth weights of 890 to 1680 g were enrolled in the study. Nine preterm infants received caffeine therapy, and 9 served as a control group. Oxygen consumption and energy expenditure were examined before, during, and after caffeine treatment. RESULTS: Oxygen consumption increased significantly from 7.0 +/- 0.9 before caffeine to 8.8 +/- 0.7 mL/kg/min after 48 hours of caffeine therapy, and energy expenditure increased from 2.1 +/- 0.3 to 3.0 +/- 0.2 kcal/kg/hour. During the observation period of 4 weeks of caffeine treatment, oxygen consumption increased significantly in the caffeine group compared with the control patients. In the caffeine group, a lower environmental temperature was sufficient to maintain a normal body temperature. With similar caloric intake in both groups during the study period, daily weight gain in the control group was significantly higher (21 +/- 4 vs 42 +/- 2 g/d). None of the other parameters recorded changed during caffeine therapy. CONCLUSION: Long-term administration of caffeine in preterm infants is associated with an increase in oxygen consumption and with a reduction of weight gain. This may have implications for clinical practice as nutritional regimens need to be adjusted during this therapy.

Apnea↗
PubMed2001

Doubling of the tuberculosis incidence in Greenland over an 8-year period (1990-1997).

OBJECTIVE: To determine the trends in conventional and molecular epidemiology of tuberculosis (TB) in Greenland over an 8-year period. DESIGN: A nation-wide, retrospective, population-based study of all cases of TB reported to the National Health Division of Greenland from 1 January 1990 to 31 December 1997. An analysis of microbiology data including RFLP results. RESULTS: The annual incidence increased from 85/100,000 in 1990 to 172/100,000 in 1997; 335 (72%) of the cases were culture-positive. On average 58% of culture-positive cases were smear-positive, with an increase from 40% in 1990 to 69% in 1997. There was a significant increase in childhood TB from four cases in 1990 to 26 in 1997. RFLP analysis shows that 15% of the patients were infected with unique strains and 85% were infected with strains belonging to one of 20 clusters. There were four major clusters, comprising respectively 52, 34, 26 and 14 patients. CONCLUSION: There was a dramatic increase in TB cases in Greenland from 1990 to 1997. The increase is due to micro-epidemics in small isolated settlements, and affects primarily young adults and children. RFLP analysis confirms this observation and indicates confined, local transmission. In this context RFLP is not useful as the only parameter for monitoring recent transmission.

Adolescent↗
PubMed2001

Losigamone add-on therapy in partial epilepsy: a placebo-controlled study.

OBJECTIVES: To evaluate the efficacy and tolerability of losigamone (LSG). PATIENTS AND METHODS: Double-blind, placebo-controlled add-on study with 3x500 mg LSG/die for the treatment of chronic partial seizures in 203 patients (99 treated with LSG, 104 on placebo). RESULTS: The median percent change of seizures was 14.9% (LSG) versus 6.7% (placebo) (P=0.004). Seizure frequency was decreased by more than 50% in 22.3% (LSG) and 14.6% (placebo) of patients (P=0.13). Mean percent change of seizures was best in patients with only one additional anticonvulsant drug (LSG versus placebo, P=0.004). Adverse events (usually CNS-related side effects of mild to moderate intensity) were reported in 59.6% (LSG) and 37.5% (placebo) of patients. CONCLUSIONS: LSG proved to be an effective and well tolerated anticonvulsant drug for the treatment of chronic partial seizures.

Adolescent↗
PubMed2001

[Tamoxifen or tamoxifen in combination with chemotherapy in adjuvant therapy of breast carcinoma. Results of a multicenter randomized study].

UNLABELLED: Between April 1994 and May 1997 103 breast cancer patients (pts), pT1c-3a, pN0-1, M0, were randomised after surgery to adjuvant tamoxifen (20 mg per day) or to tamoxifen plus CMF (C 500 mg/m2, M 40 mg/m2 and F 600 mg/m2 on days 1st and 8th q 28 day) in 6 cycles. The median age (49-72 years, median 58), tumour size, number of involved lymphnodes (0-3), estrogens receptor status, grade (I-III) and type of operation were well balanced among the 50 pts on tamoxifen and the 53 pts on tamoxifen plus CMF pts, preferably postmenopausal. RESULTS: Grade of toxicity according to WHO criteria was not higher then two in both arms. Toxicity both haematological and non-haematological was higher in the group treated with chemotherapy (0 vs 32 resp. 20%) except weight gain (52% in both group). After median follow-up of 42 mos five recurrences in tamoxifen and seven in tamoxifen plus CMF pts were observed (p = NS). The projected 3-y DFS is 92% for tamoxifen and 88% for tamoxifen plus CMF (p = NS). The 3-y OS is 88% for tamoxifen and 80% for tamoxifen plus CMF pts (p = NS). CONCLUSIONS: Both regimens are equally effective with higher toxicity in the group with combined chemo- and hormonal therapy.

Aged↗
PubMed2000

Synthesis, characterization, and structural and theoretical analysis of Gd4B3C4: a novel rare earth metal borocarbide containing two different boron-carbon arrangements.

The synthesis by arc-melting techniques, the single-crystal X-ray structure, and the theoretical analysis of Gd4B3C4 are reported. It crystallizes in the triclinic space group P1 with a = 3.637(2) A, b = 3.674(2) A, c = 11.859(5) A, alpha = 93.34(5) degrees, beta = 96.77(5) degrees, gamma = 90.24(5) degrees, and Z = 1. In this structure, the boron and carbon atoms form two different types of nonmetal arrangements: 1-D (BC)infinity branched chains and finite (0-D) linear CBC "molecular" units. Gd4B3C4 is the first characterized member of the rare earth metal borocarbide series in which both 1-D and "molecular" 0-D nonmetal atom systems coexist. From the structural and theoretical analysis, the following formal charge distribution can be proposed within the ionic limit: (Gd3+)4(BC2(5-)(BC3-)2.e-. Tight-binding calculations suggest that the excess electron in the ionic limit is mainly localized on the Gd atoms (at the bottom of the 5d band), while LAPW calculations favor its localization on the (BC)infinity chain. The bonding within this compound is fully analyzed and compared to other members of the rare earth metal borocarbide series.

Journal Article↗
PubMed2000

Rhesus monkeys are highly susceptible to experimental autoimmune encephalomyelitis induced by myelin oligodendrocyte glycoprotein: characterisation of immunodominant T- and B-cell epitopes.

Eight rhesus monkeys with different MHC backgrounds were immunized with myelin oligodendrocyte glycoprotein (MOG). All developed severe experimental autoimmune encephalomyelitis associated with large inflammatory foci and extensive demyelination. T-cell autoreactivity to MOG was directed against three main epitopes encompassed within amino acids 4-20, 35-50 and 94-116, of which two are also immunodominant epitopes for the autoimmune T cell response to MOG in patients with MS. A strong B cell response to MOG was observed in all monkeys and major epitopes recognized were located within amino acids 4-26, 24-46 and 44-66/54-76.

Animals↗
PubMed2000

Serum androgens return to normal after temporal lobe epilepsy surgery in men.

BACKGROUND: Epileptic discharges from the temporal lobe may influence the release of hormones from the hypothalamic-pituitary axis. If epilepsy surgery influences the underlying epileptic disorder one might expect serum hormone concentrations to return to normal following surgery. PATIENTS: Twenty-two men with epilepsy aged 25 to 48 years (mean, 34.9 years) were investigated before surgery and at 3, 6, and 12 months after surgery. Medication (all patients received carbamazepine) was maintained following surgery. METHODS: Hormone measurements included luteinizing hormone, follicle stimulating hormone, estradiol, testosterone, free testosterone, androstenedione, prolactin, dehydroepiandrosterone sulfate, cortisol, growth hormone, and sex hormone-binding globulin. These hormone levels were compared with those of 105 healthy men (mean age, 33.9 years). RESULTS: Fourteen of the 22 patients (63.6%) achieved total seizure control following epilepsy surgery. The 14 patients with successful seizure control entered further analysis. Before surgery these patients' free testosterone and androstenedione concentrations were significantly lower compared with healthy men. In seven of the 14 patients a significant increase of hormone serum concentrations could be demonstrated for testosterone, free testosterone, and androstenedione. Laterality of epileptic focus, enzyme-inducing medication, stress, and the decreasing number of patients during the follow-up did not correlate with the finding of a normalization of serum androgens. PATIENTS without complete seizure control did not show an increase in serum androgen concentrations. CONCLUSION: Successful temporal lobe epilepsy surgery may lead to a normalization of serum androgen concentrations in men with epilepsy.

Adult↗
PubMed2000

An interlaboratory comparison of physiological and genetic properties of four Saccharomyces cerevisiae strains.

To select a Saccharomyces cerevisiae reference strain amenable to experimental techniques used in (molecular) genetic, physiological and biochemical engineering research, a variety of properties were studied in four diploid, prototrophic laboratory strains. The following parameters were investigated: 1) maximum specific growth rate in shake-flask cultures; 2) biomass yields on glucose during growth on defined media in batch cultures and steady-state chemostat cultures under controlled conditions with respect to pH and dissolved oxygen concentration; 3) the critical specific growth rate above which aerobic fermentation becomes apparent in glucose-limited accelerostat cultures; 4) sporulation and mating efficiency; and 5) transformation efficiency via the lithium-acetate, bicine, and electroporation methods. On the basis of physiological as well as genetic properties, strains from the CEN.PK family were selected as a platform for cell-factory research on the stoichiometry and kinetics of growth and product formation.

Journal Article↗
PubMed2000

The major protein import receptor of plastids is essential for chloroplast biogenesis.

Light triggers the developmental programme in plants that leads to the production of photosynthetically active chloroplasts from non-photosynthetic proplastids. During this chloroplast biogenesis, the photosynthetic apparatus is rapidly assembled, mostly from nuclear-encoded imported proteins, which are synthesized in the cytosol as precursors with cleavable amino-terminal targeting sequences called transit sequences. Protein translocon complexes at the outer (Toc complex) and inner (Tic complex) envelope membranes recognize these transit sequences, leading to the precursors being imported. The Toc complex in the pea consists of three major components, Toc75, Toc34 and Toc159 (formerly termed Toc86). Toc159, which is an integral membrane GTPase, functions as a transit-sequence receptor. Here we show that Arabidopsis thaliana Toc159 (atToc159) is essential for the biogenesis of chloroplasts. In an Arabidopsis mutant (ppi2) that lacks atToc159, photosynthetic proteins that are normally abundant are transcriptionally repressed, and are found in much smaller amounts in the plastids, although ppi2 does not affect either the expression or the import of less abundant non-photosynthetic plastid proteins. These findings indicate that atToc159 is required for the quantitative import of photosynthetic proteins. Two proteins that are related to atToc159 (atToc120 and atToc132) probably help to maintain basal protein import in ppi2, and so constitute components of alternative, atToc159-independent import pathways.

Amino Acid Sequence↗
PubMed2000

Application of binary buffer systems to free flow cell electrophoresis.

The applicability of free flow electrophoresis (FFE) was expanded towards processing of sensitive cells. The chamber medium was adjusted to a physiologic pH of 7.35 by a mixture of N-(2-hydroxyethyl)piperazine-N'-(3-propanesulfonic acid) (EPPS) and 2,2-bis(hydroxymethyl)-2,2'2"-nitrilotriethanol (BISTRIS). These substances proved to be nontoxic to sensitive cells such as human smooth muscle or thyroid cells. They enhanced the electrical conductivity of the medium only slightly so that a new cell electrophoresis separation medium could be prepared, which contained 30 mM NaCl together with or without 1 mM CaCl2 but did not generate problems of overheating the fluid. Suspended in this medium, human smooth muscle cells as well as human thyroid carcinoma cells remained viable single cells for at least 120 min. After this period they could be recultured to form monolayers. If electrophoresed in the Octopus preparative FFE device, they migrated as single cells and did not clot; therefore, their electrophoretic behavior could be determined exactly.

Cell Separation↗
PubMed2000

Establishment and characterization of the follicular thyroid carcinoma cell line ML-1.

The present study focuses on the establishment and characterization of a new follicular thyroid carcinoma cell line. The human cell line ML-1 was derived from a dedifferentiated follicular thyroid carcinoma relapse, which progressed despite preceding surgery followed by two radioiodine therapies. More than 90% of the cells of this line express thyroglobulin, chondroitin sulfate, and vimentin antigens, but only about 70% show cytokeratin filaments and a negative surface charge density such as human erythrocytes. More importantly, cells of this line are able to take up iodine and/or glucose both in vitro and in vivo and to secrete thyroglobulin, chondroitin sulfate, and fibronectin into the interstitial space. In addition, triiodothyronine is released constitutively into culture supernatants. Moreover, it is also suitable for xenotransplantation studies because it is tumorigenic in NMRI nude mice in vivo. The cell line forms tumors with follicular structures when transplanted to nude mice. Due to these unique features the ML-1 cell line can be considered as a very suitable test model for pharmacological and cell biological studies. Since chemicals may interfere with the production of thyroid hormones, this cell line represents also a tool for toxicological investigations.

Adenocarcinoma, Follicular↗
PubMed2000

[Therapy of generalized tonic-clonic status epilepticus in adulthood].

If continuous seizure activity lasts longer than 5 minutes generalized tonic-clonic seizures require prompt treatment, if significant morbidity and mortality are to be avoided. The mortality varies (mean: 20%) depending on patient age and etiology. Control of status epilepticus is achieved by benzodiazepines in about 80% of cases: Lorazepam is recommended due to its longer-acting effects on the central nervous system. To maintain the anticonvulsive effect phenytoin is usually administered intravenously. Fosphenytoin (not approved in Germany) has advantages over phenytoin, because it can be given three times more rapidly and produces fewer side effects. The IV use of valproic acid in status epilepticus seems to be promising, but needs further evaluation. There is no generally accepted treatment protocol for the therapy of persistent seizure activity lasting more than 60 minutes (i.e., refractory status epilepticus). Usually phenobarbital, or general anesthesia with thiopental or pentobarbital are treatment recommendations. In recent reports, the administration of midazolam or propofol proved to be effective and well-tolerated.

Anticonvulsants↗
PubMed2000

[Topiramate (Topamax). Pharmacological characteristics and current use in epilepsy treatment].

Topiramate (Topamax) has been registered since July 1998 and has market authorization for the Federal Republic of Germany as an additive drug for the treatment of patients (age 12 or older) suffering from intractable partial and secondarily generalized seizures. The anticonvulsant effect of topiramate is based on three mechanisms: (a) modulating the blocking of the Na channels activated by voltage, depending on status, (b) potentiation of GABAA-mediated inhibiting neurotransmission, and (c) inhibition of excitatory neurotransmission by blocking APMA glutamate receptors. Topiramate exhibits a substantial anticonvulsive effect on partial seizures both with and without secondary generalization. The median reduction in seizure frequency using topiramate as adjunct therapy was 44%. In 44% of patients, seizure frequency was reduced by more than 50%, and seizure reduction was more than 75% in nearly half of these (i.e., in 21% of all patients), while 5% of patients remained completely free of seizures. Adverse events most often caused central nervous disturbances. Weight loss, the development of renal calculi, and impairment of cognitive functions may occur. It is recommended to start therapy with topiramate at a daily dosage of 25 mg, increasing by 25 mg every week up to 200-400 mg/day but not exceeding 1000 mg/day.

Anticonvulsants↗
PubMed2000

Prefrontal cortical hypometabolism during low-dose interferon alpha treatment.

OBJECTIVE: To evaluate prospectively interferon alpha (IFN-alpha) associated effects on cerebral glucose metabolism and its correlation to neuropsychiatric symptoms during low-dose IFN-alpha-treatment. METHODS: Eleven patients treated with low-dose IFN-alpha for chronic hepatitis C were prospectively evaluated by neuropsychiatric tests and cerebral [18F]deoxyglucose positron emission tomography (FDG-PET) before and in the 12th week of treatment. PET images were spatially normalized, corrected for variance in global activity and pixel-based t-statistics were calculated for each set of PET scans using SPM96 software. Pixel-cluster with P<0.001 for hypo- or hypermetabolism were displayed in parametric images. Covariance analysis with neuropsychiatric tests was calculated for each cluster. RESULTS: In week 12 of IFN-alpha treatment, significant hypometabolism with a decrease of local activity ranging from 8 to 12% was found in all patients bilaterally in the prefrontal cortex (BA 9), which correlated in a covariate analysis with changes in depression score as measured by Beck's Depression Inventory. Additionally, hypermetabolism with a maximum increase in local activity of 6-8% was seen in all patients in putamina as well as the left occipital region (BA 18). Before IFN-alpha treatment, only 1/11 patient showed depressive symptomatology. After 3 months of treatment, 6/11 patients were classified as having mild to moderate depressive symptoms (P<0.1; Wilcoxon test). CONCLUSIONS: Low-dose IFN-alpha therapy is associated with significant prefrontal hypometabolism. This hypometabolism covaried with depression score, but was even found in clinically non-depressed patients. These findings may reflect a possible predisposing factor for IFN-alpha associated neuropsychiatric syndromes and might contribute to a pathophysiological model of affective disorders, as endogenous IFN-alpha levels are elevated in a subset of psychotic patients during acute disease.

Adult↗
PubMed2000

A new primate model for multiple sclerosis in the common marmoset.

Experimental autoimmune encephalomyelitis (EAE) in outbred marmoset monkeys (Callithrix jacchus) is a recently developed nonhuman primate model of multiple sclerosis. Here, Bert 't Hart and colleagues compare this model to EAE in rhesus monkeys, highlighting autoimmune mechanisms in CNS inflammation and demyelination, including the role of major histocompatibility complex restriction and preclinical evaluation of innovative immunotherapies.

Acute Disease↗
PubMed2000

Polycystic ovary syndrome in patients with focal epilepsy: a study in 93 women.

A prospective cohort analysis of premenopausal women with focal epilepsy was conducted in order to determine whether polycystic ovary syndrome (PCOS) is a common finding in women treated with antiepileptic drugs (AED). This study was carried out in 93 of 150 women (aged between 20 and 53 years; mean, 34.3 years) with chronic focal epilepsy consecutively cared for at the Department of Epileptology, University of Bonn: 38 were receiving one AED (18 valproate, 20 carbamazepine), 36 more than one drug, and 19 were without medication. Patients were followed-up for 6 months. PCOS was defined as hyperandrogenism (testosterone concentration, > 0.7 ng/ml) combined with oligomenorrhoea (cycle length, > 35 days) or amenorrhoea. PCOS was identified in two out of 19 (10.5%) patients receiving no medication; in four of 38 (10.5%) of patients receiving monotherapy, and in none of the patients receiving more than one AED. The incidence of PCOS in patients treated with valproate monotherapy (11.1%) was similar to that in patients treated with carbamazepine (10%) and also to that in patients not treated with AEDs. The results of this study suggest that the manifestation of PCOS in women with focal epilepsy is not related to the administration of valproate or carbamazepine.

Adult↗