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Biomedical subjects

W Lang

Publications and source records attributed to W Lang.

At least 127 records · Page 7Linked to original sources
PubMed1998

The influence of the state of the vertebral arteries on the peri- and postoperative risk in carotid surgery.

OBJECTIVES: To assess the significance of the vertebral arteries (VA) as a prognostic factor within the framework of carotid surgery. DESIGN: Prospective observational study. MATERIALS: A total of 1338 operations were performed on 1182 patients. Three hundred and six of the patients had angiographically confirmed unilateral (299) or bilateral (seven) involvement of the VA. In 31 cases it was not possible to assess the VA. METHODS: Life table analysis. RESULTS: Thirty-day mortality rate was 1.6% (21 out of 1338) for all reconstructions of the internal carotid artery. In addition to three fatal strokes, 22 hemispheric events were noted (1.6%, 22/1338). Follow-up varied between 1 and 96 months (mean 34, S.E.M. 0.76, median 29) and covered a total of 3361 patient years. The cumulative 5-year survival rate was 69%. Irrespective of age, cardiac events were the leading cause of death. In patients with VA involvement, both the 30-day stroke and mortality rate (p < 0.01) and the long-term survival rate (p < 0.01) were significantly poorer. CONCLUSION: Concomitant vertebral artery disease increases the morbidity and mortality of carotid surgery, presumably due to reduced collateral perfusion during cross-clamping. However, the overall risk of surgery remains acceptable.

Aged↗
PubMed1998

Bioelectrical impedance analysis to assess body composition in obese adult women: the effect of ethnicity.

OBJECTIVE: To examine whether the accuracy of bioelectrical impedance analysis (BIA) to estimate body composition in overweight women is affected by the ethnicity of the individuals. DESIGN: Cross-sectional design to compare body composition estimated by BIA to body composition measured by dual energy x-ray absorptiometry (DEXA), which was the reference method. SUBJECTS: One hundred twenty three overweight women participated in this study, of which 43 women were African-American (aged 37.2+/-5.6 y; BMI, 32.3+/-4.9 kg/m2) and 80 were Caucasian (aged 36.1+/-5.7 y; BMI, 31.9+/-3.5 kg/m2). MEASUREMENTS: Body composition was estimated from BIA using both a generalized and an obesity-specific equation. These estimations were compared to body composition measured by DEXA, which was the reference method. RESULTS: The generalized BIA equation underestimated lean body mass (LBM) by 2.6+/-3.1 kg in Caucasian women and 0.4+/-3.2 kg in African-American women, with the difference between the ethnic groups being significant (P < 0.001). The obesity-specific equation underestimated LBM in Caucasians by 0.9+/-3.1 kg and overestimated LBM in African-Americans by 1.2+/-2.8 kg (P < 0.001). An ethnic-specific equation is proposed, and cross-validation of this equation indicates that it provides a reasonable estimate of body composition in overweight women. CONCLUSIONS: The accuracy of BIA to estimate body composition appears to be affected by the ethnicity of the individual. Therefore, an ethnic-specific equation for overweight women is proposed. However, further validation of this prediction model in an ethnically diverse population is necessary.

Absorptiometry, Photon↗
PubMed1998

Valaciclovir for the suppression of recurrent genital herpes simplex virus infection: a large-scale dose range-finding study. International Valaciclovir HSV Study Group.

A randomized, double-blind study of valaciclovir for suppression of recurrent genital herpes was conducted among 1479 immunocompetent patients. Patients were randomized to receive valaciclovir (250 mg, 500 mg, or 1 g once daily, or 250 mg twice daily), acyclovir (400 mg twice daily), or placebo, for 1 year. All valaciclovir dosages were significantly more effective than placebo at preventing or delaying recurrences (P < .0001). There was a dose-response relationship (P < .0001) across the once-daily valaciclovir regimens. Twice-daily valaciclovir and acyclovir were similar in effectiveness. Subgroup analysis showed that patients with a history of < 10 recurrences per year were effectively managed with 500 mg of valaciclovir once daily. One gram of valaciclovir once daily, 250 mg of valaciclovir twice daily, or 400 mg of acyclovir twice daily were more effective in patients with > or = 10 recurrences per year. Safety profiles of all treatments were comparable. Thus, valaciclovir is highly effective and well tolerated for suppression of recurrent genital herpes. Once-daily regimens offer a useful option for patients who require suppressive therapy for management of genital herpes.

Acyclovir↗
PubMed1998

Hypoplasia, stenosis and other alterations of the vertebral artery: does impaired blood rheology manifest a hidden disease?

OBJECTIVES: The clinical relevance of abnormal vessel findings in the posterior circulation is still a matter of controversy. PATIENTS AND METHODS: We compared 48 patients displaying sonographic abnormalities of one vertebral artery, i.e., vertebral artery hypoplasia in 24 cases, stenosis in 13 cases, plaques in 11 cases, with 25 healthy subjects in terms of whole blood viscoelasticity and plasma viscosity. RESULTS: All patients with stenosis and plaques suffered from clinical signs and symptoms of ischemic cerebrovascular disease, predominantly in the posterior circulation. Free of acute clinical symptoms were 5 of the 24 patients with hypoplasia. Highly statistically significant differences in blood viscoelasticity were found between the patients and the healthy subjects. As regards differences between the groups, whole blood viscoelasticity was most impaired in stenosis, shear resistance was significantly higher in stenosis compared to hypoplasia. Symptom-free patients with one-sided vertebral artery hypoplasia had a significantly better, nearly normal blood rheology at a low shear rate (10/s), compared to clinically symptomatic patients with hypoplasia. CONCLUSION: The results of the present study offer some evidence that altered hemorheology may be associated with symptomatic vertebrobasilar occlusive disease.

Arterial Occlusive Diseases↗
PubMed1998

Comparison of near-infrared spectroscopy and somatosensory evoked potentials for the detection of cerebral ischemia during carotid endarterectomy.

BACKGROUND AND PURPOSE: We sought to assess the clinical value of regional cerebral saturation (rSO2) obtained by means of the cerebral oximeter INVOS 3100A (Somanetics) in comparison to monitoring of somatosensory evoked potentials (SEP) for the reliable detection of severe cerebral ischemia requiring shunt placement in the individual patient undergoing carotid surgery under general anesthesia. METHODS: In 317 patients undergoing reconstructive surgery on the internal carotid artery, simultaneous recordings of SEP and rSO2 were obtained throughout the operation. RESULTS: All 287 patients with preserved cortical SEP remained neurologically intact. Shunt placement was performed in 27 patients (9%) after flattening of cortical SEP during cross-clamping of the internal carotid artery. A stable rSO2 value just before cross-clamping and the lowest value after cross-clamping were registered, and the decrease was calculated. A statistically significant (P<0.01) decrease of rSO2 after cross-clamping could be found in patients without (64.9+/-8.3% to 60.9+/-9.9%) as well as in patients with consecutive loss of cortical SEP (65.8+/-9.1% to 56.1+/-13.4%). The difference of the decrease of rSO2 in both groups was highly significant (6.9+/-9.0% versus 15.6+/-14.0%; P<0.001). However, substantial interindividual variability of rSO2 and derived change of rSO2 did not allow the definition of a threshold value indicating need of shunt placement. CONCLUSIONS: The reliability of SEP for the detection of clamp-related hypoperfusion has been reaffirmed. As long as rSO2 threshold values indicating critical cerebral ischemia are not defined, therapeutic interventions based on monitoring with the cerebral oximeter INVOS 3100A are not justified.

Adult↗
PubMed1998

Combined operative and endovascular treatment of a post-traumatic embolizing aneurysm of the subclavian artery.

PURPOSE: To describe a combined endovascular and surgical approach for an embolizing subclavian artery aneurysm as an alternative to conventional reconstructive surgery. METHODS AND RESULTS: A 39-year-old woman presented with a post-traumatic aneurysm of the left subclavian artery and occlusion of the brachial artery due to embolization. Exclusion of the aneurysm was achieved by intraoperative implantation of a covered stent during simultaneous reconstruction of the brachial artery by a venous bypass graft. The patient is well and free of symptoms 24 months after the operation. CONCLUSIONS: Repeat operative trauma to the supraclavicular region was avoided by transluminal implantation of a covered stent-graft in combination with an axilloulnar bypass procedure for chronic embolic occlusion of the brachial artery.

Adult↗
PubMed1998

Lifestyle intervention in overweight individuals with a family history of diabetes.

OBJECTIVE: To assess the effect of lifestyle intervention over 2 years on changes in weight, coronary heart disease (CHD) risk factors, and incidence of diabetes in overweight individuals with a parental history of diabetes. RESEARCH DESIGN AND METHODS: Participants (n = 154), who were 30-100% over ideal body weight, had one or both parents with diabetes, and were currently nondiabetic, were randomly assigned to 2-year treatments focused on diet (decreasing calories and fat intake), exercise (goal of 1,500 kcal/week of moderate activity), or the combination of diet plus exercise or to a no-treatment control group. Subjects were reassessed at 6 months, 1 year, and 2 years. RESULTS: At 6 months, the groups differed significantly on measures of eating, exercise, and fitness; weight losses in the diet and diet-plus-exercise groups were significantly greater than in the exercise and control conditions. Weight losses were associated with positive changes in CHD risk factors. After 6 months, there was gradual deterioration of behavioral and physiological changes, so that at 2 years, almost no between-group differences were maintained. Differences between groups in risk of developing diabetes were of borderline significance (P = 0.08). Strongest predictors were impaired glucose tolerance at baseline, which was positively related to risk of developing diabetes, and weight loss from baseline to 2 years, which was negatively related; in all treatment groups, a modest weight loss of 4.5 kg reduced the risk of type 2 diabetes by approximately 30% compared with no weight loss. CONCLUSIONS: Although initially successful, the interventions studied here were not effective in producing long-term changes in behavior, weight, or physiological parameters. However, weight loss from 0 to 2 years reduced the risk of developing type 2 diabetes. Since modest weight loss significantly reduced risk of type 2 diabetes, further research is needed to determine how best to increase the percentage of subjects achieving at least a modest weight loss.

Adult↗
PubMed1998

[How can the prognosis of acute mesenteric artery ischemia be improved? Results of a retrospective analysis].

AIM: Acute mesenteric ischemia is difficult to diagnose and is combined with a high mortality. In a retrospective analysis it was investigated how to improve the poor prognosis of the disease. PATIENTS AND METHODS: Between January 1988 through December 1994 a total of 46 patients were operated on for acute mesenteric ischemia. Mesenteric artery occlusion was present in three quarters of the cases (n = 35). These were analysed according to symptoms, diagnosis, mechanism of occlusion, operative procedure and prognosis. Distribution of gender was almost balanced (19 women, 16 men) with a median age of 70.5 years. RESULTS: Embolic arterial occlusion was predominant (n = 22). Most frequently, the superior mesenteric artery was exclusively concerned (n = 22). Serum levels of lactate and leucocytes were preoperatively elevated in over 90% (median values: lactate 53 U/l, leucocytes 15050/ml). In 16 patients diagnosis was made on the ground of clinical parameters and/or angiography, but 19 patients were not diagnosed until operation. 19 patients were operated within 6 hours, 12 patients within 24 hours after admission (> 24 hours: n = 4). Vascular reconstructive procedures only, such as thrombectomy and/or aortomesenteric bypass were performed in 9 cases, in a further 7 cases combined with bowel resection. Bowel resection alone was done in 7 patients, 12 patients had only diagnostic laparotomy. 13 patients survived, 10 of them had been treated with vascular reconstruction. CONCLUSION: Acute mesenteric ischemia ought to be suspected in every patient with uncertain abdominal pain, because only early diagnosis can improve prognosis. Measurement of serum lactate is diagnostically helpful, although not proving. In case of elevated lactate levels and uncertain abdominal symptoms angiography of the mesenteric vessels should be performed early. At operation, blood flow in the mesenteric arteries should be restored whenever possible.

Acute Disease↗
PubMed1998

Knitted double-velour Dacron prostheses in aortobifemoral position--long-term performance of different coating materials.

BACKGROUND: The purpose of this prospectively randomized study was to evaluate intraoperative as well as long-term performance of different coating materials for knitted Dacron aortobifemoral prostheses. PATIENTS AND METHODS: Between 1989 and 1992 a total of 150 consecutive patients who underwent aortobifemoral bypass were randomized for three different coating materials: gelatine (Unigraft; n = 49), collagen (Hemashield; n = 50) and human albumin (USCI; n = 51). Intra- and perioperative data such as duration of operation, clamping time, blood loss, and early complications were obtained as well as yearly follow-up examinations up to five years. Frequency of late complications, graft patency, and patient survival were observed. RESULTS: No statistically significant difference of intraoperative data could be obtained. In every group 6% of patients presented with anastomotic aneurysm in the groin. Primary patency rates were Unigraft 92%, Hemashield 91%, USCI 92% (no significant difference, n.s.), secondary patency rates after 5 years were Unigraft 98%, Hemashield 95%, USCI 94% (n.s.). CONCLUSIONS: Overall superiority of one particular type of prosthesis could not be stated. In order to prevent sudden graft failure associated with progressive arteriosclerotic disease or from late anastomotic aneurysm regular follow-up examinations should follow aorto-bifemoral bypass.

Aorta, Abdominal↗
PubMed1998

[Do patients with changes in the vertebral arteries have an increased risk in carotid artery obliteration?].

There was no difference between the groups investigated in terms of the preoperative neurological stages. In patients with VA involvement, both the 30-day mortality rate (p < 0.01) and the long-term survival rate (p < 0.01) were significantly poorer. In the study group, the incidence of shunt procedures was three times as high as in the control group (p < 0.01).

Carotid Artery, Internal↗
PubMed1997

[A protocol for the assessment of patients with coma of unknown origin].

OBJECTIVE: Evaluation of the applicability of a protocol designed for the quick and efficient management of patients with coma of unknown origin (CUO). METHODS: Every patient admitted to our Emergency Department with the diagnosis of CUO was evaluated with our diagnostic protocol. The first diagnostic steps included evaluation of the hemodynamic and respiratory situation, Glasgow Coma Scale, basic neurologic and clinical examination, as well as blood withdrawal, for analysis of metabolic and toxicologic parameters. If indicated, cranial computer tomography (CCT) and/or lumbar puncture were performed. RESULTS: Within the study period from 1. 1. 1995 until 30. 9. 1996, 122 patients (65 males, median age 50 years, 25 and 75 percentile: 33; 69) were included. Blood analysis and the toxicological screening were diagnostic effective in 66 patients, clinical examination and body temperature in one case each, CCT in 50 patients and lumbar puncture in 2 patients. By the use of this diagnostic protocol 51 neurologic, 38 toxicologic, 28 metabolic and 2 infectious causes of coma were diagnosed (98%). Etiology of 2 of the comas remained unclear. CONCLUSION: By using our protocol, 98% of the causes of CUO were clarified. The main causes of coma were of neurological, toxicological and metabolic origin. CCT and the blood analysis were the most important procedures leading to a final diagnosis.

Adult↗
PubMed1997

Molecular cloning of a putative tetrodotoxin-resistant sodium channel from dog nodose ganglion neurons.

Voltage-gated tetrodotoxin (TTX)-resistant sodium channels present in primary sensory neurons may be responsible for the excitability of nociceptors, and may underlie pain and tenderness associated with tissue injury and inflammation. Here, we report the cloning of a putative sodium channel (NaNG) from dog nodose ganglia. The sequence of the full-length cDNA predicts an open reading frame of 5886 nucleotides encoding a protein of 1962 amino acids. The predicted protein shows 82.3% identity with the recently discovered TTX-resistant sodium channel (SNS/PN3). In the TTX-binding site, a serine appears as in TTX-resistant SNS/PN3, instead of Cys (as in TTX-insensitive cardiac channels) and Tyr/Phe (as in TTX-sensitive sodium channels). Coupled transcription and translation of full-length cDNA produced a 220-kDa protein; based on Northern blot and RT-PCR analysis, its expression is restricted to nodose ganglia, and not present in cortex, hippocampus, cerebellum, liver, heart or skeletal muscle. We propose that NaNG might be a new member of the TTX-resistant sodium channel family expressed in sensory neurons.

Amino Acid Sequence↗
PubMed1997

The hospital discharge decision for patients with community-acquired pneumonia. Results from the Pneumonia Patient Outcomes Research Team cohort study.

BACKGROUND: The hospital discharge decision directly influences the length of stay in patients with community-acquired pneumonia, yet no information exists on how physicians make this decision. OBJECTIVES: To identify the factors physicians considered the factors responsible for extending length of hospital stay in clinically stable patients, and the outpatient medical services that would allow earlier hospital discharge for patients with community-acquired pneumonia. METHODS: Physicians responsible for the hospital discharge decision of patients with community-acquired pneumonia were asked to identify the factors responsible for extending stay in patients hospitalized beyond stability, and the medical services that could have allowed earlier hospital discharge to occur. RESULTS: For the 418 eligible patients with community-acquired pneumonia identified during the study, 332 questionnaires (79%) were completed by 168 physicians. Physicians believed 71 patients (22%) were discharged from the hospital 1 day or more (median, 2.5 days) after reaching clinical stability. The most common factors rated as being "very important" in delaying discharge were diagnostic evaluation or treatment of comorbid illness (56%), completion of a "standard course" of antimicrobials (15%), and delays with arrangements for long-term care (14%). Among the 302 patients with available information on both length of hospital stay and stability at discharge, median length of stay was 7.0 days for the 29 low-risk patients hospitalized beyond reaching clinical stability and 5.0 days for the remaining 128 low-risk patients (P < .005); median length of stay was 12.5 days for the 42 medium- and high-risk patients hospitalized beyond reaching clinical stability and 8.0 days in the remaining 113 medium- and high-risk patients (P < .001). Frequently cited medical services that "probably" or "definitely" would have allowed earlier discharge to occur included availability of home intravenous antimicrobial infusion (26%) and home visits by nurses (20%). CONCLUSIONS: Physicians believed that diagnostic evaluation or treatment of comorbid illness, completion of a standard course of antimicrobial therapy, and delays with arrangements for long-term care delayed hospital discharge in clinically stable patients. Addressing the efficiency of these aspects of inpatient medical care, as well as providing home treatment programs, could decrease the length of hospital stay in patients with community-acquired pneumonia.

Adult↗
PubMed1997

Cortical DC potential shifts accompanying the central processing of visually presented analogue and digital time displays.

According to studies in brain-lesioned patients, the cortical substrate subserving the reading of digitally presented time displays seems to differ from that of reading analogue displays. While the right hemisphere has been assumed to be important for reading analogue displays, reading digital displays is attributed to the left hemisphere. This study attempts to localize the cortical substrate of reading analogue versus digital time displays in the intact human brain using scalp-recorded event-related slow negative DC potential shifts. In the arithmetic tasks, subjects had to judge whether or not the time conveyed by the last out of three tachistoscopically presented (analogue or digital) slides was the exact difference between the time conveyed by the first and the second slide. In the control condition, subjects only had to attend to (analogue or digital) time displays. With analogue slides, frontolateral recording sites revealed a right hemispheric preponderance of DC shifts measured in the interval between the second and third slide. Anterior temporal recording sites revealed a right hemispheric preponderance only when calculations were performed. By contrast, there was no hemispheric lateralization with digital slides. The arithmetic versus control manipulation modulated waveforms, but did not influence hemispheric laterality.

Adult↗
PubMed1997

Brain/behaviour dissociation on old/new distinction in a patient with amnesic syndrome.

Event-related potentials (ERP) were recorded in a recognition memory task in 5 healthy subjects and an amnesic patient. A list of high-imagery words with low probability in everyday language was presented visually for 200 ms each. A second list, consisting of 50% previously presented ('old') words and 50% 'new' words was presented immediately after the first list. Old/new distinction was determined by the subject's motor response. For each subject single trial analysis of ERPs was performed. In each healthy subjects, correct old/new distinction was associated with significant ERP differences from 500 to 900 ms after stimulus onset. It was, therefore, assumed that task and recording procedures were appropriate for the study of ERPs with recognition memory. The main finding is a dissociation between brain activity and behaviour with old/new distinction in the patient with amnesic syndrome. Frequently, the patient incorrectly classified previously shown words ('old' words) to be presented for the first time ('new'). But ERP showed that brain processing of 'old' words which had incorrectly been classified to be 'new' is different from correctly classified new words. ERP differences were significant between 900 and 1200 ms after stimulus presentation. These data indicate preserved memory functions which are not assessed at the behavioural level in the memory recognition task.

Adult↗
PubMed1997

Color Doppler imaging versus phlebography in the diagnosis of deep leg and pelvic vein thrombosis.

The objective of this prospective study was to evaluate the accuracy of color Doppler imaging in comparison to phlebography in diagnosing phlebothrombosis. Five hundred and twenty-six phlebographies (reference method) were compared with 526 color Doppler sonographic examinations. Thrombosis diagnosed with color Doppler imaging showed a sensitivity of 98.0% (400 of 408). In 91.6% (482 of 526) of all examinations the extent of the thrombosis diagnosed with phlebography could also be seen with color Doppler imaging. When the clinical situation is unclear, color Doppler imaging should precede phlebography. Only when findings with ultrasonography are questionable should phlebography definitely be considered.

Adolescent↗
PubMed1997

Elucidation of phase I and phase II metabolic pathways of rhein: species differences and their potential relevance.

Because of previously observed species differences in rhein tolerability, with rabbits being very susceptible to kidney disturbances, in vivo and in vitro biotransformation studies were performed to find out whether the differences in the undesired effects of rhein are associated with qualitative, species-dependent differences in its metabolism. First hints on species-dependent biotransformation profiles were obtained from in vivo experiments with 14C-labeled rhein in rat, rabbit, dog, and man. TLC-analysis of urine samples obtained after oral administration of 14C-rhein to rabbits revealed an additional, hydrophilic metabolite fraction in rabbit urine as compared with dog and human urine, all of which contain phenolic monoglucuronide and monosulfate as major metabolites. An investigation of urine samples (obtained from dogs, rabbits, rats, and human volunteers after oral application of unlabeled rhein) was conducted by means of mass spectrometric tandem techniques including on-line HPLC-MS/MS. In vitro experiments with subcellular liver fractions of rats and rabbits revealed the presence of three monohydroxylated metabolites of rhein, their quinoid oxidation products, and a bishydroxylated derivative of rhein. The hydroxylated phase I metabolites were detected as glucuronides in urine samples of all investigated species, whereas the quinoid product was present only in rabbit urine. Moreover, two regioisomeric phenolic glucuronides and sulfates or glucosides of rhein were found as major phase II metabolites in urine of all species. Furthermore, acyl glucuronides of rhein and monohydroxylated rhein and their respective isomeric acyl migration products were identified in human urine. In rabbit urine we discovered different bisglucuronides (bisphenolic glucuronide, mixed ether/ ester glucuronides), whereas in rats only the bisether/ether glucuronide was present. In addition, the investigations of dog and human urine showed the formation of two regioisomeric phenolic glucosides. With respect to a potential reactivity with endogenous macromolecules the quinoid metabolites as well as the bisester/ether glucuronides appear most relevant.

Animals↗