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Biomedical subjects

R Oberbauer

Publications and source records attributed to R Oberbauer.

At least 55 records · Page 3Linked to original sources
PubMed1996

Craniocerebral birth trauma caused by vacuum extraction: a case of growing skull fracture as a perinatal complication.

A case of growing skull fracture following birth trauma and caused by vacuum extraction is reported in order to emphasize the incidence of this peculiar head injury at the beginning of extrauterine life and to point out its relation to possible neuropsychological disturbances that may appear later in childhood. Delivery by vacuum extraction increases the incidence of perinatal injuries and consequently the incidence of neurological deficits in children. Neurosurgical repair is advocated as the appropriate treatment, with the aim not only of cosmetically correcting the lesion's typical subgaleal protuberance with cranioplasty, but also of performing a water-tight closure of the dura, enabling the cerebral cortex to "fill in" the intracerebral lesion. The surgical technique and gross pathology of the lesion are described together with radiological findings before and after surgery. Reports by other authors are reviewed in an attempt to identify the conditioning factors and pathological features of this traumatic injury to skull and brain in neonates and infants. The literature on cranial fractures associated with intracerebral lesions at this age shows a significant difference in recovery and outcome from that after similar lesions in older children.

Female↗
PubMed1996

Antisense and the kidney.

Antisense oligonucleotides are being used as gene-therapeutic agents. This short overview focuses on the in vivo kinetics and on potential in vivo applications for research purposes as well as therapeutic applications. The most promising experimental results have been obtained with oligonucleotides targeted against genes involved in cell proliferation, such as c-myc, c-myb, Kras, and cdc-2. High parenteral doses of such oligonucleotides have limited growth of experimental tumors, and local application of such oligonucleotides has limited neointimal proliferation in injured arteries. Therapeutic use of antisense in the kidney seems more distant. Because proximal tubule cells take up circulating oligonucleotides, transient suppression of proximal tubule message expression may be obtained following parenteral oligonucleotide administration. More sophisticated delivery systems, however, will be required to achieve antisense efficacy over longer periods and in other compartments of the kidney.

Animals↗
PubMed1995

Pharmacokinetics and pharmacodynamics of the diuretic bumetanide in the elderly.

In a cross-sectional study of the pharmacokinetics and pharmacodynamics of peroral and intravenous bumetanide (0.5 mg, single dose), total and renal clearance of the diuretic was significantly lower in elderly persons than in young adults, resulting in higher bumetanide plasma levels in the aged. Nonrenal clearance, bioavailability, and the volume of distribution were not significantly changed. Together with the decreased delivery into the urine the diuretic and natriuretic effect of bumetanide was reduced in the elderly. Renal clearance of bumetanide was linearly related with creatinine clearance, hence the decreases in bumetanide clearance and diuretic efficacy in the elderly are attributed to the age-dependent decline in renal function. The bumetanide concentration in urine and the fractional sodium excretion were not different in the two age groups, suggesting that the decrease in diuretic response in the elderly is a result of a reduction in the number of functioning nephrons, whereas the response of the remaining nephrons to bumetanide is unaltered.

Administration, Oral↗
PubMed1995

Renal uptake of an 18-mer phosphorothioate oligonucleotide.

Renal uptake of a 35S labeled 18-mer phosphorothioate oligodeoxynucleotide (molecular wt approximately 6,000) was evaluated following intravenous infusion into rats. The kidneys contained 21 +/- 3% of the infused dose at five hours after infusion and 3 +/- 1% of the infused dose at four days after infusion. The concentration of oligonucleotide was greater in the kidney than in the liver, spleen, or plasma at both intervals. Urine excretion of oligonucleotide label averaged 17 +/- 1%, 35 +/- 5%, and 64 +/- 3% of the infused dose at five hours, one day, and four days after infusion. Electrophoresis (PAGE) showed that oligonucleotide was retained in the kidney was the intact 18-mer at both five hours and four days after infusion, while full size oligonucleotide was not found in the urine at either interval. Light microscopic autoradiography showed that oligonucleotide uptake was most prominent in the early proximal tubule. Electron microscopic autoradiography indicated that oligonucleotide was not confined to the brush border or endocytic-lysosomal pathway. Micropuncture studies showed that the tubule fluid to plasma concentration ratios of oligonucleotide label averaged 7 +/- 3% in Bowman's space and 6 +/- 2% in the distal tubule. Despite restriction of filtration by plasma protein binding, as indicated by the low Bowman's space to plasma concentration ratio, the calculated tubular reabsorption rate for oligonucleotide was sufficient to account for the large amount of oligonucleotide found in the kidney after intravenous infusion. These results indicate that the proximal tubule plays a prominent role in the disposition of intravenously infused oligonucleotide, and raise the possibility that oligonucleotides could exert antisense effects in this nephron segment.

Animals↗
PubMed1995

Glomerular permselectivity in proteinuric patients after kidney transplantation.

To characterize the defect in glomerular permselectivity responsible for proteinuria after renal transplantation, we studied 10 patients with moderate proteinuria (median 0.37 g/d, range 0.20-0.79), 16 patients with the nephrotic syndrome (6.73 g/d, 3.9-14.6), 8 living related donor transplant recipients without any history of rejection (median proteinuria 0.26 g/d, 0.06-0.58), and 12 healthy volunteers. The fractional clearance of neutral dextrans > 54 A was significantly higher in nephrotic patients, demonstrating a defect in glomerular size selectivity. Using a log-normal model of glomerular pore size distribution, r*(5%) and r*(1%), indices for the presence of large pores, were increased in the nephrotic patients. The fractional clearance of negatively charged dextran sulfate was significantly higher in all patient groups, indicating a loss of glomerular charge selectivity. Biopsy findings showed more prominent glomerular lesions in the nephrotic group compared with the moderately proteinuric group. We conclude that mild proteinuria late after renal transplantation is associated with a defect in glomerular charge selectivity. The development of nephrotic range proteinuria is associated also with a defect of glomerular size selectivity, which correlates with prominent glomerular pathology.

Adult↗
PubMed1995

The effects of prolonged substitution of recombinant human growth hormone on renal functional reserve in growth hormone-deficient adults.

Twelve growth hormone (GH)-deficient adults with normal renal function were recruited for a 6-month, double-blind, placebo-controlled study on the effects of prolonged recombinant human growth hormone (rhGH) substitution therapy on renal functional parameters. RhGH was administered at a dose 0.125 IU/kg per week sc the first 4 wk and 0.25 IU/kg per week thereafter. At baseline and after 6 months of therapy, GFR and RPF were measured by the use of iothalamate and para- aminohippurate clearance techniques before and after an intravenous infusion of amino acids (AA) to determine the renal functional reserve capacity (RFRC). At baseline, GFR and RPF were similar in the GH-deficient patients and a group of normal, healthy controls (GFR, 117 +/- 10 mL/min; RPF, 567 +/- 57 mL/min, and filtration fraction, 22 +/- 1.6% in the patient group and GFR, 117 +/- 10 mL/min; RPF, 509 +/- 54 mL/min; and filtration fraction, 24 +/- 1.3% in the control group). GFR increased significantly in the control and patient group after AA infusion; the RFRC, however, was significantly larger in healthy individuals (GFR post-AA infusion, 141 +/- 10 mL in GH-deficient patients and 182 +/- 20 mL/min in controls). Thereafter, six patients received placebo therapy for 6 months and GFR as well as RFRC remained constant (GFR, 107 +/- 9 and 106 +/- 12 mL/min before AA infusion and 132 +/- 14 and 134 +/- 5 mL/min after AA infusion at baseline and after 6 months, respectively). Four patients of the placebo group then continued with rhGH therapy for another 6 months. They and six patients who had rhGH therapy from the beginning form the rhGH treatment study group. During rhGH treatment, plasma insulin-like growth factor activity increased significantly from 93 +/- 17 to 229 +/- 23 ng/mL. Baseline GFR and RPF as well as RFRC were unaltered by the 6 months of rhGH replacement therapy (basal GFR, 124 +/- 7 mL/min before and 123 +/- 9 mL/min after 6 months of rhGH therapy; GFR after AA infusion, 145 +/- 9 mL/min at baseline and 144 +/- 8 mL/min after 6 months of therapy). Kidney size as evaluated by ultrasonography was normal at baseline when compared with that in age- and sex-matched controls (10.3 +/- 0.2 versus 9.9 +/- 0.1 cm) and was unchanged after 6 months of therapy (10.3 +/- 0.3 cm). It was concluded from this study that rhGH substitution for 6 months at a dose of 0.25 IU/kg per week in GH-deficient patients with normal renal function has no adverse functional effects on the kidney.

Adult↗
PubMed1994

Follow-up and quality of survival of 67 consecutive children with CNS tumors.

We report the findings at follow-up in 67 consecutive children with central nervous system tumors treated over a 5-year-period at a single institution. The diagnoses were supratentorial astrocytoma (n = 12), cerebellar astrocytoma (n = 10), ependymoma (n = 9), medulloblastoma (n = 9), brain stem glioma (n = 6), optic pathway glioma (n = 5), and others (n = 16). The survival rates were 83% for supratentorial astrocytomas at a median of 46.5 months, 90% for cerebellar astrocytomas and 55% for ependymomas at 40 months, respectively, 55% for medulloblastomas at 22 months, 33% for brain stem gliomas at 23 months, and 80% for optic pathway gliomas at 49 months. With regard to neurological sequelae, 13 patients were treated for epilepsy, 13 patients had mild to moderate neurological deficits, and 4 patients were severely disabled. Seventeen of 37 tested patients performed below average on formal neuropsychometric testing, one-fourth attended special education courses, and at least one-fourth suffered from behavioral and adjustment problems.

Adolescent↗
PubMed1993

Pharmacokinetics of indomethacin in the elderly.

In a cross-sectional study the pharmacokinetics of indomethacin were studied in old and young adults without manifest organ failure. Total clearance of indomethacin after a single oral dose of 50mg was 0.8 ml/min/kg in elderly individuals (mean 79.5 +/- 1.3 years) compared with 1.4 ml/min/kg in younger individuals (mean 36.9 +/- 3.0 years). The apparent elimination rate constant averaged 0.23 h-1 in the aged and 0.32 h-1 in the young people. Oral bioavailability was close to 1 in the young but 0.77 in the elderly. The apparent volume of distribution was similar in each group. Based on these results it is suggested that the maintenance dose of indomethacin be reduced by 25% in the elderly.

Administration, Oral↗
PubMed1992

Hyperfractionated radiotherapy and polychemotherapy in brain stem tumors in children.

Between October 1989 and January 1991 five children with brain stem tumors were treated with sequential chemo- and radiotherapy. The polychemotherapy consisted of procarbazine, ifosfamide, etoposide, methotrexate, cisplatin and cytosine arabinoside. Locally, hyperfractionated radiotherapy was delivered at a total dose of 63.8 Gy (1.1 Gy twice daily, 10 fractions per week). After a median observation time of 11.8 (range 4-23) months from diagnosis three children are alive and without evidence of tumor progression. Two patients died from tumor progression 11 and 16 months respectively after initiation of therapy.

Adolescent↗
PubMed1991

[Oligosymptomatic Bourneville-Pringle tuberous sclerosis of the brain with giant cell astrocytoma].

We report on a 9-year-old boy who developed subependymal giant-cell astrocytoma associated with tuberous sclerosis. Apart from a few hypopigmented skin patches, the boy's clinical picture was completely unremarkable until the onset of diplopia and vertigo reflecting increased intracranial pressure. Magnetic resonance imaging of the brain revealed subcortical hamartomas in addition to the intraventricular tumour. Seizures and mental retardation were absent. The boy's mother had suffered from seizures during childhood and presented with typical skin lesions. The importance of thorough examination and regular follow-up even in patients with oligosymptomatic variants of tuberous sclerosis is emphasized.

Adult↗
PubMed1991

[Oligosymptomatic variant of tuberous sclerosis with subependymal giant cell astrocytoma].

We report on a 9-year-old boy who developed subependymal giant-cell astrocytoma associated with tuberous sclerosis. Remarkably, the boy was not mentally retarded and never had suffered from seizures. Apart from white skin patches symptoms of increased intracranial pressure were the presenting symptoms. The boy's mother, who was present at the boy's admission, presented with skin lesions typical of tuberous sclerosis. The importance of thorough examination of apparently asymptomatic relatives of patients with tuberous sclerosis is emphasized.

Astrocytoma↗
PubMed1990

[Precipitating factors for shunt insufficiency in post-hemorrhagic hydrocephalus in the premature infant].

Between January 1984 and March 1989 twenty-seven low birth weight infants (mean birth weight 1351 gm, mean gestational age 30 weeks) required shunts after development of a posthaemorrhagic hydrocephalus. Revision of the shunt occurred in 78% of the patients with a range of 1 to 11 revisions. Obstruction of the ventricular catheter was the main cause of mechanical complications that occurred in 75%. Preterm infants weighing less than 1000 gm revealed an enormous infection rate of 71%. Initial shunt placement in the first 8 weeks of life was more likely to need shunt revision (94%) than that placed at older age (44%). There was no difference between the type of shunt and percentage of shunt revision, but the Heyer-Schulte system in comparison with the Codman Uni shunt was more likely to have mechanical complications. Infants with Grade IV haemorrhage required the same percentage of revisions as those with Grade III haemorrhage. There was no association between preoperative therapy and the need for shunt revision. A great amount of erythrocytes and very low glucose levels in the preoperative CSF were more likely to predict shunt revision than predicted by the CSF protein.

Birth Weight↗
PubMed1982

The influence of skull defects and reperfusion after extra-intracranial arterial bypass surgery on the sensorimotor EEG rhythm.

Twelve patients with small burr hole skull defects after extra-intracranial arterial bypass surgery were studied. The amplitude and frequency of the sensorimotor rhythm were measured 7 days and 1, 2, 4, and 6 months after surgery in follow-up EEGs from the central region. Seven patients showed a frequency decrease (compared with preoperative measurement) on the operated side 7 days and/or 1 month after surgery. There was no case of frequency decrease 6 months after surgery; four patients displayed a late frequency increase. Ipsilateral amplitude enhancement was never found 7 days postoperatively, but after 6 months in nine patients. Such physical factors as burr holes and bone replacement can only partially explain the amplitude enhancement, and cannot explain the frequency decrease. It may be assumed that temporary clamping of the middle cerebral artery and/or reperfusion of an ischaemic area result in a brief deterioration of brain function, as indicated by frequency slowing and delayed amplitude enhancement; related observations were made in patients with cerebrovascular disorders and mild to moderate neurological deficit about 20 days after the onset and correlated with clinical recovery.

Adult↗
PubMed1982

Computer tomography in children with stroke.

31 children aged between 6 weeks and 15 years, who had suffered a stroke, were investigated by computer tomography (CT). 8 patients had suffered transient ischemic attacks (TIA), 17 had completed ischemic strokes and 6 had hemorrhagic strokes. The mean interval between the stroke and the first CT investigation was 5 days. In the group of 8 patients with transient ischemic attacks, 1 patient had a small infarct, 1 had atrophy and 2 exhibited A-V malformations. In the group of 17 patients with completed ischemic strokes, 14 showed an infarct, 5 had atrophy and in 1 an angioma was found. All 6 hematomas were detected by CT. In follow-up studies, 11 of 17 patients with ischemic stroke showed atrophy.

Adolescent↗