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Biomedical subjects

R Urban

Publications and source records attributed to R Urban.

At least 19 recordsLinked to original sources
PubMed2006

Ovarian cancer in younger vs older women: a population-based analysis.

To compare the clinico-pathologic prognostic factors and survival of younger vs older women diagnosed with epithelial ovarian cancer. Demographic, clinico-pathologic, treatment, and surgery information were obtained from patients with ovarian cancer from the Surveillance, Epidemiology, and End Results Program from 1988 to 2001 and analysed using Kaplan-Meier estimates. Of 28 165 patients, 400 were <30 years (very young), 11 601 were 30-60 (young), and 16 164 were >60 (older) years of age. Of the very young, young, and older patients, 261 (65.3%), 4664 (40.2%), and 3643 (22.5%) had stage I-II disease, respectively (P<0.001). Across all stages, very young women had a significant survival advantage over the young and older groups with 5-year disease-specific survival estimates at 78.8% vs 58.8 and 35.3%, respectively (P<0.001). This survival difference between the age groups persists even after adjusting for race, stage, grade, and surgical treatment. Reproductive age (16-40 years) women with stage I-II epithelial ovarian cancer who received uterine-sparing procedures had similar survivals compared to those who underwent standard surgery (93.3% vs 91.5%, P=0.26). Younger women with epithelial ovarian cancer have a survival advantage compared to older patients.

Adenocarcinoma, Clear Cell↗
PubMed2005

Consensus guidelines on screening for hypopituitarism following traumatic brain injury.

PRIMARY OBJECTIVE: The goal of this consensus statement is to increase awareness among endocrinologists and physicians treating patients with traumatic brain injury (TBI) of the incidence and risks of hypopituitarism among patients with TBI. RATIONALE: TBI poses significant risk to the pituitary gland, leading to elevated risks of diabetes, hypopituitarism and other endocrinopathies. Signs and symptoms associated with hypopituitarism often mimic the sequellae of TBI, although the severity of symptoms is not necessarily related to the severity of the injury. Patients with TBI-induced hypopituitarism may benefit both physically and psychologically from appropriate hormone replacement therapy (HRT). Participants at this unique consensus meeting attempted to define and spearhead an approach to increase awareness of the risks of TBI-induced endocrinopathies, in particular growth hormone deficiency (GHD), and to outline necessary and practical objectives for managing this condition. RECOMMENDATIONS: Systematic screening of pituitary function is recommended for all patients with moderate-to-severe TBI at risk of developing pituitary deficits. Patients with hypopituitarism benefit from appropriate hormonal replacement and prospects for rehabilitation of patients with TBI-induced hypopituitarism may be enhanced by appropriate HRT. Further exploration of this possibility requires: (1) active collaboration between divisions of endocrinology and rehabilitation at the local level to perform a screening of pituitary function in patients after TBI, (2) creation of a consultancy service by endocrine societies for use by rehabilitation centres, (3) development of continuing medical education (CME) programmes that can be offered as crossover training to the physicians who manage the care of patients with TBIs, (4) targeting of patient organizations with educational information for dissemination to patients and their families, (5) continued efforts to more clearly define the population at greatest risk of TBI-induced hypopituitarism and (6) monitor results of efficacy studies as they become available to evaluate whether and how much replacement therapy can improve the symptoms of individuals with TBI-induced hypopituitarism.

Brain Injuries↗
PubMed2005

Production of stem cells with embryonic characteristics from human umbilical cord blood.

When will embryonic stem cells reach the clinic? The answer is simple -- not soon! To produce large quantities of homogeneous tissue for transplantation, without feeder layers, and with the appropriate recipient's immunological phenotype, is a significant scientific hindrance, although adult stem (ADS) cells provide an alternative, more ethically acceptable, source. The annual global 100 million human birth rate proposes umbilical cord blood (UCB) as the largest untouched stem cell source, with advantages of naive immune status and relatively unshortened telomere length. Here, we report the world's first reproducible production of cells expressing embryonic stem cell markers, - cord-blood-derived embryonic-like stem cells (CBEs). UCB, after elective birth by Caesarean section, has been separated by sequential immunomagnetic removal of nucleate granulocytes, erythrocytes and haemopoietic myeloid/lymphoid progenitors. After 7 days of high density culture in microflasks, (10(5) cells/ml, IMDM, FCS 10%, thrombopoietin 10 ng/ml, flt3-ligand 50 ng/ml, c-kit ligand 20 ng/ml). CBE colonies formed adherent to the substrata; these were maintained for 6 weeks, then were subcultured and continued for a minimum 13 weeks. CBEs were positive for TRA-1-60, TRA-1-81, SSEA-4, SSEA-3 and Oct-4, but not SSEA-1, indicative of restriction in the human stem cell compartment. The CBEs were also microgravity--bioreactor cultured with hepatocyte growth medium (IMDM, FCS 10%, HGF 20 ng/ml, bFGF 10 ng/ml, EGF 10 ng/ml, c-kit ligand 10 ng/ml). After 4 weeks the cells were found to express characteristic hepatic markers, cytokeratin-18, alpha-foetoprotein and albumin. Thus, such CBEs are a viable human alternative from embryonic stem cells for stem cell research, without ethical constraint and with potential for clinical applications.

Antigens, Surface↗
PubMed2003

Assessment of fetal distress based on magnetic resonance examinations: preliminary report.

RATIONALE AND OBJECTIVES: Hypoxia is the main cause of injuries and intrauterine death of the fetus. Therefore, the main aim of monitoring and assessment of the fetus should be diagnosis of fetal distress before irreversible changes occur. Besides the fetal condition assessment methods used so far, in recent years in obstetrics new non-invasive imaging methods were introduced such as magnetic resonance (MR). This method enables morphologic evaluation of brain and brain tissue metabolism using magnetic resonance spectroscopy (MRS). MATERIALS AND METHODS: Twenty pregnant women with pregnancy-induced hypertension (11 cases, including 3 with coexisting diabetes mellitus and 2 with intrauterine growth retardation), chronic hypertension (2 cases), gestational diabetes mellitus (6 cases), and suspected intrauterine fetal growth retardation (IUGR) participated in the study. Cardiotocography (CTG) and Doppler ultrasound examination of the blood flow in the umbilical artery and in the middle cerebral artery were performed. RESULTS: In case of abnormal CTG and Doppler study records that indicated fetal hypoxia, MR studies showed the existence of ischemic focus in 5 patients and abnormal spectral images in 6 patients. CONCLUSION: The results of the preliminary study suggests that the use of MR in prenatal diagnosis may revolutionize the early detection of fetal injury in fetal distress. It is a valuable component of the diagnostic process, supplementing other examinations. The use of MR to assess fetal condition gives additional information and helps to make decisions about therapeutic actions.

Adult↗
PubMed2002

[Vertebral body stenting. A method for repositioning and augmenting vertebral compression fractures].

UNLABELLED: Purpose of the study was to demonstrate the effectiveness of expanding a fractured vertebral body by transpedicular dilatation and stenting. 7 human cadaveric vertebral bodies from L2 to L5 underwent axia compression until a vertebral burst fracture was provoked. Then, by bilateral transpedicular approach, balloon-catheters were introduced, which were armed with stents, usually used for angioplasty. The catheters were inflated with radiolucent fluid and the stents expanded under radiologic control. After expansion, the balloon was deflated and removed, the stents resting inside the vertebral body, holding their inflated shape. Then, the resulting hole was filled with an injectable biodegradable calcium-phosphate. CT-scans were performed after destruction and after expansion. Morphology before and after expansion was judged, using 3-D reconstructions. Vertebral body strength was measured before destruction and after treatment with an Instron testing machine. RESULTS: Vertebral body shape could be restored. Also impressed central parts of the bony endplate could be elevated by using a convergent approach through the pedicles. There was no collapse of the vertebral body after removing the catheter-balloons The vertebral body strength could be restored up to a physiologic level. This procedure gives new perspectives in the treatment either of osteoporotic compression or traumatic vertebral fracture. By using CT-guided technique, it could be performed by a minimally invasive approach percutaneously.

Aged↗
PubMed2001

Gilbert damping in single and multilayer ultrathin films: role of interfaces in nonlocal spin dynamics.

Unique features of the Gilbert damping in magnetic multilayers were investigated by ferromagnetic resonance (FMR) using magnetic single and double layer structures prepared by molecular beam epitaxy. The FMR linewidth for the Fe films in the double layer structures was larger than the FMR linewidth in the single Fe films having the same thickness. The additional FMR linewidth scaled inversely with the film thickness, and increased linearly with increasing microwave frequency. These results demonstrate that a transfer of electron angular momentum between the magnetic layers leads to additional relaxation torques.

Journal Article↗
PubMed2001

Manifestations in four males with and an obligate carrier of the Lenz microphthalmia syndrome.

Lenz microphthalmia syndrome is a rare X-linked recessive condition first described by Lenz in 1955 and comprises of anophthalmia, microcephaly, mental retardation, external ear, digital, cardiac, skeletal, and urogenital anomalies. We present three brothers (ages 15 years, 9 years, and 18 months) and a maternal uncle (age 27 years) with congenital anophthalmia, delayed motor development, hypotonia, and moderate to severe mental retardation. They also have abnormally modeled ears, high-arched palate, pectus excavatum, finger and toe syndactyly, clinodactyly, fetal pads, scoliosis, cardiac, and renal abnormalities. An obligate carrier had abnormally modeled ears and syndactyly of the 2nd to 3rd toes bilaterally. Linkage and haplotype analysis in this family indicates that the gene is located in a 17.65-cM region on chromosome region Xq27-Xq28.

Abnormalities, Multiple↗
PubMed2001

Use of a calcium sulfate-based bone graft substitute for benign bone lesions.

Twenty-three patients with a benign bone lesion grafted with calcium sulfate, with and without demineralized bone matrix, were reviewed. At a minimum of 1 year postoperatively, 21 patients had achieved between 76% and 100% bone repair based on anteroposterior and lateral radiographs. Overall, the mean Enneking Functional Evaluation System score was 98%. Calcium sulfate is a well-tolerated, biodegradable, osteoconductive bone graft substitute. It is a reasonable alternative to autogenous bone graft for benign bone lesions.

Absorbable Implants↗
PubMed2000

Steroid-dependent up-regulation of adipose leptin secretion in vitro during pregnancy in mice.

Circulating leptin levels are elevated during the later stages of pregnancy in mammals, suggesting that maternal leptin may play a role in maintenance of pregnancy and/or preparation for parturition and lactation. The regulation and source of circulating leptin during pregnancy remains undetermined, but leptin mRNA levels increase in adipose tissue during this time in some species. Considerable controversy exists whether placenta is also a leptin-secreting tissue during pregnancy. Here, we directly demonstrate that leptin secretion rates from mouse adipose tissue in vitro are decreased during early pregnancy and up-regulated during late pregnancy and lactation. Changes in leptin secretion rates in vitro paralleled those of circulating leptin in vivo during gestation. Subcutaneous implants of estradiol or corticosterone into lactating mice for 48 h stimulated adipose leptin secretion rates in vitro to the level of that in pregnant mice. However, corticosterone, but not estradiol, increased leptin secretion when added to isolated adipose tissue in vitro. Placentae obtained at two stages of pregnancy did not secrete leptin in vitro, either when acutely isolated or when dissociated into cells for long-term cultures. Placental tissue (or cells) secreted progesterone, however, demonstrating placental viability. We conclude that hyperleptinemia during late pregnancy in mice primarily results from corticosterone-dependent up-regulation of leptin secretion from adipose tissue, and that the placenta does not contribute to leptin secretion. The initial decrease in leptin secretory rates from adipose tissue during early pregnancy may facilitate energy storage for the subsequent, increased metabolic demands of later pregnancy and lactation.

Adipose Tissue↗
PubMed2000

Duration tuning in the mouse auditory midbrain.

Temporal cues, including sound duration, are important for sound identification. Neurons tuned to the duration of pure tones were first discovered in the auditory system of frogs and bats and were discussed as specific adaptations in these animals. More recently duration sensitivity has also been described in the chinchilla midbrain and the cat auditory cortex, indicating that it might be a more general phenomenon than previously thought. However, it is unclear whether duration tuning in mammals is robust in face of changes of stimulus parameters other than duration. Using extracellular single-cell recordings in the mouse inferior colliculus, we found 55% of cells to be sensitive to stimulus duration showing long-pass, short-pass, or band-pass filter characteristics. For most neurons, a change in some other stimulus parameter, (e.g., intensity, frequency, binaural conditions, or using noise instead of pure tones) altered and sometimes abolished duration-tuning characteristics. Thus in many neurons duration tuning is interdependent with other stimulus parameters and, hence, might be context dependent. A small number of inferior colliculus neurons, in particular band-pass neurons, exhibited stable filter characteristics and could therefore be referred to as "duration selective." These findings support the idea that duration tuning is a general phenomenon in the mammalian auditory system.

Acoustic Stimulation↗
PubMed2000

[The Doppler cerebroplacental ratios and perinatal outcome in post-term pregnancy].

Our purpose was to determine whether the Doppler cerebroplacental ratios predicts perinatal outcome in postterm pregnancy. The middle cerebral to umbilical artery resistant and pulsatility indices (MCA PI/UA PI and MCA RI/UA RI) were measured in 59 postterm pregnancies. We found significant correlation between MCA PI/UA PI, MCA RI/UA RI, nonstress testing and intrapartum fetal heart rate assessment. There was also an association between MCA PI/UA PI and 1- and 5-minute Apgar score. We conclude that the Doppler cerebroplacental ratios provide useful information about perinatal outcome.

Brain↗
PubMed2000

Testosterone and muscle protein metabolism.

This presentation discusses recent investigations into testosterone's effects on muscle protein metabolism. Protein synthesis is the principal end point, but protein breakdown and the availability of an amino acid pool are important to the process of net muscle protein synthesis. The effects of other hormones--including growth hormone, oxoandrolone (a synthetically derived testosterone), and androstenedione--on muscle protein synthesis also are discussed. Effects in both normal and elderly men are considered.

Aged↗
PubMed2000

[The amniotic fluid of term and preterm delivery and its influence on contractions of human myometrium in vitro].

Initiation of labour is a complex process that involves fetal-maternal communication. Although the mechanism of the initiation of preterm labour has not been elucidated fully, it may differ from that in normal labour. The aim of this research was to study the effect of amniotic fluid from term and preterm deliveries on human myometrial contractions. The amniotic fluid was obtained from 45 women, who underwent caesarean section preterm (18) and at term (27) for routine obstetric indications. The influence of preterm and term amniotic fluid on spontaneous and oxytocin stimulated by in vitro isometric myometrial contractions was evaluated. Repeated measured ANOVA was performed for statistical analysis. Amniotic fluid from preterm delivery successfully inhibits myometrial contractions stimulated by oxytocin, so it may play role in maintaining normal pregnancy and preventing preterm delivery.

Adult↗
PubMed1999

Uterine and fetal Doppler flow changes after misoprostol and oxytocin therapy for induction of labor in post-term pregnancies.

OBJECTIVES: To compare the effect of misoprostol vs. oxytocin on blood flow in uteroplacental circulation during labor induction. METHODS: Ninety-one women with indications for induction of labor were assigned to receive either misoprostol 50 microg per vagina every 4 h as needed or intravenous oxytocin by means of a randomization table generated by computer. Doppler velocimetry of umbilical, uterine and arcuate arteries was performed immediately before and 2-3 h after administration of misoprostol or oxytocin. Pulsatility index (PI), resistance index (RI) and systolic/diastolic (S/D) ratios were measured for these arteries. The SAS system was used to perform statistical analysis. RESULTS: There were no significant changes of PI, RI and S/D ratios in umbilical arteries during misoprostol and oxytocin inductions. Vaginal application of misoprostol significantly increased PI, RI and S/D ratios in arcuate arteries and S/D ratio in uterine arteries. CONCLUSIONS: Our results indicate that intravaginal misoprostol administration increases uteroplacental resistance but probably does not substantially affect placental perfusion.

Administration, Intravaginal↗
PubMed1998

[Antepartum amniotic fluid index and pregnancy outcome].

Our purpose was to evaluate prognostic value of antepartum amniotic fluid index (AFI) on fetal and newborn outcome, because oligohydramnion is associated with increased risk of fetal and newborn distress. Perinatal outcome was defined by 1' and 5' Apgar score, intrapartum fetal heart rate (FHR), blood gas, acid-base status in umbilical artery, mode of delivery and meconium-stained amniotic fluid. Data was analysed with CSS Statistica for Windows package by test t for independent samples and chi 2. Prospective observations was conducted with 84 singleton pregnancies complicated by oligohydramnion (AFI < or = 5 cm). A 336 pregnant women, with normal amniotic fluid index and no complicated pregnancy, was considered as controls. No increased operative delivery and meconium-stained amniotic fluid rate was noted. There was no significant effects AFI on blood gases in umbilical artery and Apgar score. Oligohydramnion was associated with increased risk of fetal acidosis (pH < 7.16) (p = 0.009) and abnormalities of FHR (variable decelerations) (p = 0.004). Reduced AFI had poor predictive value of fetal acidosis and newborn depression positive predictive value (8-13%). Summarizing the results, our investigation showed that amniotic fluid index is only one point in the prognosis of perinatal outcome.

Adult↗
PubMed1997

Role of I1 imidazoline receptors in the sympathoinhibition produced by intracisternally administered rilmenidine and moxonidine.

The role of alpha 2-adrenoceptors and I1 imidazoline receptors in the cardiovascular effects of rilmenidine (CAS 54187-04-1), moxonidine (CAS 75438-57-2) and guanabenz (CAS 23256-50-0) was studied in conscious rabbits. In radioligand binding studies, rilmenidine and moxonidine are selective for I1 imidazoline receptors (vs. alpha 2-adrenoceptors) and guanabenz is selective for alpha 2-adrenoceptors (vs. I1 imidazoline receptors). Efaroxan (CAS 89197-00-2; selective for I1 imidazoline receptors) and yohimbine (CAS 65-19-0; selective for alpha 2-adrenoceptors) were used as antagonists. All drugs were injected into the cisterna magna. Guanabenz (1, 3, 10 and 30 micrograms kg-1), rilmenidine (1, 3, 10 and 30 micrograms kg-1) and moxonidine (0.03, 0.1, 0.3 and 1 microgram kg-1) dose-dependently lowered blood pressure, heart rate and the plasma concentration of noradrenaline. In the antagonism experiments, guanabenz (10 micrograms kg-1), rilmenidine (10 micrograms kg-1) and moxonidine (0.3 micrograms kg-1) were administered first; they caused equal hypotension. Injection of the agonists was followed by injection of efaroxan (0.3-1 microgram kg-1) or yohimbine (0.1-0.3 micrograms kg-1). Efaroxan and yohimbine were equieffective at antagonizing the effects of guanabenz. In contrast, efaroxan was more effective than yohimbine at antagonizing the effects of rilmenidine and moxonidine. The results show that intracisternally administered guanabenz, rilmenidine and moxonidine cause sympathoinhibition. alpha 2-Adrenoceptors are responsible for the sympathoinhibition produced by guanabenz. In contrast, I1 imidazoline receptors are involved in the sympathoinhibition caused by rilmenidine and moxonidine.

Adrenergic alpha-2 Receptor Antagonists↗