PubMed Health⌕ Search

Biomedical subjects

W Russ

Publications and source records attributed to W Russ.

At least 19 recordsLinked to original sources
PubMed2003

Effects of vigabatrin on brain GABA+/Cr signals in focus-distant and focus-near brain regions monitored by 1H-NMR spectroscopy.

The new antiepileptic drug vigabatrin (VGB) increases gamma-aminobutyric acid (GABA) in the brain. We compared GABA+/Cr signals measured focus-near and focus-distant and correlated it with the degree of response to VGB. Brain GABA+/Cr signals were measured in 17 epileptic patients in structurally normal appearing tissue by nuclear proton magnetic resonance (1H-NMR) spectroscopy using a special editing sequence for GABA. In 11 patients the measurements were done in brain areas distant to focus and in six near to focus. Full-responders (seizure reduction of >or=50% at the end of the treatment phase) and partial-responders (seizure reduction of >or=50% at the end of the first month of treatment but <or=50% at end of treatment) had lower GABA+/Cr signals in the hemisphere with the epileptogenic focus and increases of the GABA+/Cr signals with VGB. Non-responders (seizure reduction of <or=50%) had no side difference in the GABA+/Cr signals before treatment and no increase during treatment. These observations were made in structurally normal appearing tissue near to the focus and distant to the focus. A side difference in brain GABA+/Cr signal between the epileptogenic and non-epileptogenic hemisphere before VGB treatment correlates with an improved seizure control under VGB treatment regardless whether the measurement is done focus-near or focus-distant.

Adolescent↗
PubMed2001

Effects of vigabatrin on brain GABA+/CR signals in patients with epilepsy monitored by 1H-NMR-spectroscopy: responder characteristics.

PURPOSE: Vigabatrin (VGB) is a new antiepileptic drug that increases the human brain gamma-aminobutyric acid (GABA) level by irreversibly inhibiting GABA transaminase. Although some patients respond to VGB with a significant seizure reduction, others do not. The aim of this study was to identify possible responders before or in an early phase of VGB treatment by measuring the GABA and homocarnosine contaminated with macromolecules/creatine and phosphocreatine ratio (GABA+/Cr) signal by means of proton-nuclear magnetic resonance (1H NMR) spectroscopy. METHODS: Measurements were performed immediately before and after a titration period of 1 month (2 g/day during the past 2 weeks). A third measurement followed a maintenance period of 3 months (2 or 3 g/day). In 14 patients with drug-resistant temporal lobe epilepsy and 3 patients with occipital lobe epilepsy, GABA+/Cr was measured in the ipsilateral (i.e., epileptogenic) hemisphere and contralateral (i.e., nonepileptogenic) hemisphere in a volume of 8 cm3. RESULTS: Depending on the therapeutic efficacy of VGB, we defined three groups: (a) full responders (n = 7), (b) nonresponders (n = 7), and (c) partial responders (n = 3). The nonresponders had no significant change in the GABA+/Cr signal during the treatment compared with baseline. The full responders had a significant increase of the GABA+/Cr signal during the whole treatment phase and a lower ipsilateral level at baseline. The partial responders had also a lowered ipsilateral GABA+/Cr signal at baseline and an increase during treatment but a decrease when the seizures started again. CONCLUSIONS: Responders to VGB could be identified by a lower ipsilateral baseline GABA+/Cr signal and a steeper increase during VGB treatment. However, it was not possible to predict the duration of the response (full versus partial responder) with these criteria.

Adolescent↗
PubMed2001

[Evaluation of spine boards for X-Ray diagnostics].

PURPOSE: Spine boards are frequently used in preclinical emergency care. Different models were examined with regard to their feasibility for plain film radiography and computed tomography (CT). METHODS: Five current spine board models were measured for their dimensions and weight. Transmission of radiation [microGyls] and dose area product [cGy x cm(2)] were determined with a patient equivalent aluminium phantom. Image artifacts, image quality and resolution of anatomic details were evaluated with an anthropomorphic Alderson phantom. RESULTS: With only 6.3 kg new models show a 28 % reduction in weight, three spine boards generate lateral artifacts due to a narrow width of 41 - 42 cm. Radiation transmission of all boards was similar, however dose area products differed by up to 59 %. Image quality was impaired in 4 out of 5 boards because of image artifacts, CT scanning was not impaired with all boards. CONCLUSION: Only one board (Ferno Millenia(R)) showed sufficient properties for plain film radiography and CT. There is no suitable spine board for preclinical and clinical applications as well as for trauma radiology, further improvements of current designs are essential.

Artifacts↗
PubMed2000

[Implementation of a quality management system for the curriculum in emergency medicine education].

Medical teaching, training and education in basic and advanced life support were improved by basic quality management procedures. 3rd year medical students (n = 276) of two consequent semesters were questionnaired about their acute emergency medicine curriculum. While Group A (n = 134) received a standard course, the new course for group B (n = 142) was reorganised on the basis of the results of group A. Interventive educational measures were an increased number of models provided for exercising the students skills, and an extension of megacode training possibilities. Participation of students in course design improved the overall performance in respect of knowledge, skills and decision-making (p < 0.05). Curriculum acceptance and intrinsic motivation of students however were not positively influenced by practical training compared to traditional knowledge transfer.

Curriculum↗
PubMed1997

Oral dolasetron mesilate (MDL 73,147EF) for the control of emesis during fractionated total-body irradiation and high-dose cyclophosphamide in patients undergoing allogeneic bone marrow transplantation.

The purpose of the present study was to evaluate the efficacy and safety of oral dolasetron mesilate in the prevention of nausea and vomiting that might otherwise be induced by total-body irradiation (TBI) and high-dose cyclophosphamide. In an open non-comparative study 20 patients who received TBI for 3 days and high-dose cyclophosphamide chemotherapy for 2 days as part of their preparation for bone marrow transplantation were given oral dolasetron mesilate at dosages ranging from 50 to 200 mg 1 h before each fraction of radiotherapy and cyclophosphamide administration. Initial rescue therapy consisted of intravenous dolasetron mesilate. If nausea and vomiting remained uncontrolled, standard antiemetics were to be used. Of the 20 patients, 13 had only two emetic episodes or fewer in the 3-day TBI period. On days 1 and 2 of cyclophosphamide administration, 11 and 6 patients had fewer than two emetic episodes. From day 1 to day 3, 15 patients experienced no nausea or only mild nausea, and on the days of chemotherapy 8 and 7 patients had mild nausea or none at all. Rescue with i.v. dolasetron mesilate was needed by 3 and 6 patients during the TBI and the chemotherapy periods respectively. In 2 patients additional antiemetics were used on days 2-3 and 4-5. Mild to moderate headache was reported in 6 patients. No unexpected abnormalities were observed in haematology, biochemistry or urinalysis, and vital signs were unaffected throughout the study period. The data suggest that oral dolasetron mesilate is effective and safe for the prevention of nausea and vomiting during TBI and cyclophosphamide chemotherapy prior to bone marrow transplantation. Future controlled studies should evaluate combination antiemetic therapy with dolasetron mesilate for this indication.

Administration, Oral↗
PubMed1995

Vigabatrin in unsatisfactory controlled epilepsies. Swiss Vigabatrin Study Group.

One hundred and twenty-seven patients with uncontrolled epilepsy have been treated in an open add-on study with vigabatrin with a mean follow up of ten months. Mean duration of epilepsy prior to treatment was seven-teen years. Patients with partial seizures, with and without secondary generalisation responded best with 44% achieving a greater than 50% reduction in seizure frequency. Adverse events were primarily CNS related and reversible, two patients were withdrawn because of somnolence and eight because of behavioral disturbances. Reduction of concomittant AEDs was difficult in this population with chronic epilepsy.

Adolescent↗
PubMed1993

Differentiation of Listeria monocytogenes and Listeria innocua by 16S rRNA genes and intraspecies discrimination of Listeria monocytogenes strains by random amplified polymorphic DNA polymorphisms.

Differences in the 16S rRNA genes (16S rDNA) which can be used to discriminate Listeria monocytogenes from Listeria innocua have been detected. The 16S rDNA were amplified by polymerase chain reaction with a set of oligonucleotide primers which flank a 1.5-kb fragment. Sequence differences were observed in the V2 region of the 16S rDNA both between L. monocytogenes Scott A and L. innocua and between different L. monocytogenes serotypes. Although L. monocytogenes SLCC2371 had the same V2 region sequence as L. innocua, the two species were different within the V9 region at nucleotides 1259 and 1292, in agreement with previous studies (R.-F. Wang, W.-W. Cao, and M.G. Johnson, Appl. Environ. Microbiol. 57:3666-3670, 1991). Intraspecies discrimination of L. monocytogenes strains was achieved by using the patterns generated by random amplified polymorphic DNA primers. Although some distinction can be made within the L. monocytogenes species by their 16S rDNA sequence, a far greater discrimination within species could be made by generating random amplified polymorphic DNA patterns from chromosomal DNA. By using a number of 10-bp primers, unique patterns for each isolate which in all cases examined differentiate between various L. monocytogenes serotypes, even though they may have the same 16S rRNA sequences, could be generated.

Base Sequence↗
PubMed1992

The role of enoximone in cardiac surgery.

After cardiopulmonary bypass (CPB), some patients may require circulatory support. This study examined the role of the phosphodiesterase-III inhibitor, enoximone, in cardiac surgery. Eighty patients selected by chance were allocated randomly to two groups: 40 patients received enoximone 1.0 mg kg-1 approximately 10 min before weaning from CPB and 40 served as a control group. Additional pharmacological therapy (adrenaline, noradrenaline, nitroglycerin) was given, when necessary, by anaesthetists who were not involved in the study. In addition to standard monitoring, skin capillary blood flow was assessed using a laser Doppler technique before, during and after CPB until 2 h after the end of the operation. In the period after bypass, cardiac index was always significantly greater in the enoximone than in the control group. Systemic and pulmonary vascular resistance were less in the enoximone-treated patients, indicating a reduction in right and left ventricular wall stress. Oxygen consumption in the enoximone patients was significantly greater after CPB, whereas intrapulmonary shunting was comparable in the two groups. In comparison with baseline values, skin capillary blood flow in the enoximone patients was always greater than that in the control group. In comparison with the control patients, significantly fewer enoximone patients needed adrenaline, and in a smaller dose, even 2 h after operation, whereas more enoximone patients required noradrenaline therapy for a short period. We conclude that the use of enoximone before weaning from CPB improved overall cardiac function, reduced the need of catecholaminergic inotropic support, and provided increased organ perfusion up to 2 h after operation.

Adult↗
PubMed1990

Transcranial Doppler sonography and somatosensory evoked potential monitoring in carotid surgery.

Ninety-seven patients undergoing 103 carotid operations were studied intraoperatively using somatosensory evoked potentials after median nerve stimulation (SEP) and transcranial Doppler sonography (TCD). SEP were recorded from the scalp (C3'-Fz or C4'-Fz) and from the second cervical vertebra. The amplitude of the primary cortical response (N20P25) was measured peak-to-peak. Central conduction time (CCT) resulted from the difference between the first negative cortical (N20) and cervical (N14) response. TCD was performed using a pulsed 2-MHz-Doppler device to record the mean blood flow velocity of the middle cerebral artery (Vm-MCA) transtemporally. TCD and SEP variables were registered prior to and after carotid clamping, at short intervals during the clamping period, and after declamping. Critical SEP alterations (N20P25 less than 50% and/or CCT greater than 20% compared to the preceding values) were regarded as significant indicators of cerebral ischaemia, and selective intraluminal shunting was generally based on SEP criteria. The incidence of critical SEP changes was compared to Vm-MCA reductions greater than 60% using the Chi2-test. With SEP always recordable, additional TCD monitoring was possible in only 78 patients in our series for technical or anatomical reasons. Vm-MCA reductions greater than 60% were associated with critical SEP alterations in six cases. In five patients, Vm-MCA was reduced greater than 60% without relevant SEP changes, whereas one patient with critical SEP findings had only a minor Vm-MCA reduction (33%). In the remaining 66 cases, carotid clamping was tolerated without critical SEP changes associated with Vm-MCA reductions not exceeding 60%.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1990

[Transcranial Doppler sonography during pulsatile and non-pulsatile extracorporeal circulation].

Transcranial Doppler sonography (TCD) was used to determine the mean blood flow velocity of the middle cerebral artery (Vm-MCA) and pulsatility (systolic/diastolic flow velocity = S/D) in 25 patients undergoing aortocoronary bypass grafting before, during, and after extracorporeal circulation (ECC). Preoperatively, none of the patients had signs or symptoms of cerebrovascular disease. ECC was performed with 2.4 l/min per m2 under mild hypothermia (34 degrees C) using membrane oxygenators. After 20 min of nonpulsatile perfusion, ECC was switched to the pulsatile mode for 20 min. Nonpulsatile perfusion was applied for the remaining ECC period. Vm-MCA, S/D, mean arterial blood pressure (MABP), and nasopharyngeal temperature (T.np) were recorded continuously throughout the operation. Hematocrit and paCO2 were determined before, during, and after ECC. Following hemodilution after the introduction of ECC, Vm-MCA was significantly increased compared with the baseline values before ECC. With hematocrit and paCO2 varying insignificantly during ECC, the onset of pulsatile ECC decreased Vm-MCA and MABP simultaneously. After the re-establishment of nonpulsatile ECC, both Vm-MCA and MABP increased again. However, a linear relationship between the two variables could not be documented statistically. During pulsatile ECC, pulsatility (S/D) of the obtained TCD wave forms did not reach baseline values. In 4 cases, TCD showed cessation of diastolic blood flow velocity after induction of ECC or onset of pulsatile ECC. An increase in MABP or changes in ECC regimen promptly restored diastolic TCD signals in these cases. Our results support the concept of increased cerebral blood flow under mild hypothermic ECC. Compared with the nonpulsatile perfusion mode, we found Vm-MCA reduced during pulsatile ECC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Early detection of cerebral ischemia during carotid endarterectomy using transcranial Doppler sonography and somatosensory evoked potentials.

Cerebral function during carotid endarterectomy can reliably be monitored using somatosensory evoked potentials (SEP). Transcranial Doppler sonography (TCD) is a noninvasive method providing on-line data about cerebral hemodynamics. The combination of both techniques during carotid surgery is helpful in evaluating the hemodynamic ("input") and the functional ("output") consequences of carotid clamping within a short time. In the present report, combined TCD and SEP monitoring early detected left hemispheric ischemia in a 68-year-old woman subjected to left carotid endarterectomy. The impairment of cerebral perfusion occurred before carotid clamping due to an intraoperative thrombosis of the left internal carotid artery as could be revealed after declamping. A temporary shunt was not inserted. Postoperatively, the patient had a new transient neurological deficit. In this case, TCD correctly indicated cerebral ischemia as confirmed by SEP recording. For carotid artery surgery, combined TCD and SEP may be helpful in detecting those patients who will profit from temporary shunting if this is not done routinely.

Aged↗
PubMed1989

Effects of thiopentone and etomidate on median nerve somatosensory evoked responses.

Somatosensory evoked potentials (SEP) after median nerve stimulation were recorded in 40 patients during infusion of either 15 mg/kg bw thiopentone or 1 mg/kg bw etomidate (n = 10) within 15 min and after 0.3 mg/kg bw etomidate (n = 20). Marked alterations of SEP waveforms and changes in latencies were observed in all patients. Central conduction time (CCT) was significantly correlated to plasma thiopentone concentration. Infusion of high doses of thiopentone and etomidate was followed by a complete loss of middle and long latency components. Amplitude of the primary cortical SEP N20 was found to be unchanged after thiopentone and to be increased after etomidate, indicating the synchronizing properties of this drug. A pronounced increase in SEP latencies and CCT and waveform alterations have to be considered during hypnotic drug administration in intensive care medicine and intraoperatively.

Adult↗
PubMed1988

Aortic arch replacement by posterolateral exposure.

Aortic arch replacement was carried out in a 54 year old male patient with an unexpected type A-dissection, using partial femoro-femoral bypass and hypothermic arrest, through a left side posterolateral thoracotomy. After the replacement of the aortic arch from the ascending to the descending aorta a warm-up perfusion was done through an 8 mm side arm Dacron prosthesis attached to the descending segment of the 30 mm Dacron graft. This technique was demonstrated to be safe and protective in our patient and can be used as an alternative surgical method in the treatment of aortic arch dissection or aneurysms of the transverse aortic arch.

Aortic Dissection↗
PubMed1988

[Sedative-analgesic medication in intensive care patients needing ventilator treatment].

UNLABELLED: It was the aim of this study to compare two regimens for sedation and analgesia during ventilator treatment in intensive care patients. Special regard was given to endocrine stress response, neuro-monitoring, hemodynamic parameters and clinical practicability. METHODS: A total number of 16 patients of an operative ICU were randomly allocated to the following groups: (1) Fentanyl-group, approximately 0.2 mg/h fentanyl, 2.5 mg/h midazolam and 2 mg/h pancuronium in intermittent doses, (2) ketamine-group, about 50 mg/h ketamine and 2.5 mg/h midazolam by syringe pump, in addition 2 mg/h pancuronium. During a period of 2 days and in intervalls of 6 h, plasma levels of epinephrine and norepinephrine (by HPLC/ECD), ADH, ACTH and cortisol (by RIA), ketamine (by GC) and stress-metabolites (glucose, lactate, free glycerol) were determined. Hemodynamic parameters were investigated in intervalls of 12 h, EEG (Compressed Spectral Array, CSA) in intervalls of 24 h. In addition, routine laboratory data, vigilance and adaptation to the respirator were observed. RESULTS: Plasma levels of adrenaline, noradrenaline, dopamine, ADH, ACTH, cortisol and stress-metabolites were comparable in both groups. Levels of ADH, ACTH, cortisol and free glycerol did not leave the normal range. In three patients, in which epinephrine- or norepinephrine-infusions were necessary to improve cardiocirculatory stability, this treatment could be finished after beginning of the ketamine application. In both groups, CSA showed a dominant delta- und theta-activity according to the clinical aspects of sufficient sedation and analgesia. Hemodynamic parameters were comparable in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

[Transcranial Doppler sonography as an intraoperative monitoring procedure. Initial experiences in aortocoronary bypass operations].

Changes in blood velocity in the middle cerebral artery (MFV) were investigated by transcranial Doppler sonography (TCD) in 24 patients undergoing aortocoronary bypass grafting before, during, and after extracorporeal circulation (ECC). Simultaneously, mean arterial blood pressure (MABP), PaCO2, PaO2, and hematocrit were recorded. During ECC, an increase in MFV could be observed that was most pronounced during the early bypass stages. After ECC, MFV decreased slightly but was significantly higher than before ECC. No linear relationship between MFV and MABP could be registered except for the early bypass stage. Neither duration of ECC nor aortic clamping time showed any correlation with MFV augmentation. Mean PaCO2 was held constant (36 mmHg) with PaO2 being at least 120 mmHg. After removal of the aortic clamp, high-frequency Doppler signals probably caused by air or fragment embolization were detected in some patients. Our data support previous observations of increased cerebral blood flow during nonpulsatile ECC. During short episodes of low-pressure perfusion after initiation of ECC, cerebral autoregulation seemed impaired. However, our results do not support the concept of complete loss of autoregulation during ECC. Compared to the xenon technique of measuring cerebral blood flow, TCD allows noninvasive and continuous evaluation of cerebral hemodynamics, thus offering new possibilities of monitoring cerebral blood supply intraoperatively.

Adult↗
PubMed1988

[Evoked potentials and inhalation anesthetics].

Intraoperative monitoring of evoked potentials can be affected by various factors including volatile anaesthetics. These effects have to be considered in order to give correct interpretations of the obtained data. Visual evoked potentials (VEP) and auditory evoked potentials (AEP) will show strong alterations under general anaesthesia whereas brainstem auditory evoked potentials (BAEP) are slightly affected. The effects of nitrous oxide, halothane, enflurane, and isoflurane on somatosensory evoked potentials (SEP) after median nerve stimulation were studied in 35 healthy adult patients. pCO2 and tympanic membrane temperature were held constant. Simultaneous cervical and cortical SEP recording was performed using surface electrodes. After induction of anaesthesia SEP were recorded during normoventilation with 100% oxygen and after inhalation of 66.6% nitrous oxide. 10 patients received halothane at inspired concentrations of 0.5, 1.0, 1.5, and 2.0%. After nitrous oxide had been replaced by oxygen, halothane was reduced in steps of 0.5%. SEP were recorded at the end of each period (15 min). Equipotent doses of enflurane or isoflurane were administered to 15 and 10 patients, respectively. Nitrous oxide depressed early cortical SEP amplitude. Halothane, enflurane, and isoflurane caused dose dependent increases of latencies. Reduction of amplitude was most pronounced with isoflurane. Using high doses of enflurane in oxygen cortical SEP showed unusual high amplitudes associated with marked increases of latencies. Even under high concentrations of volatile anaesthetics cervical SEP were minimally affected. The effects of anaesthetic gases have to be considered when SEP are recorded intraoperatively.

Anesthesia, Inhalation↗