Search PubMed⌕ Search

Biomedical subjects

G Lenz

Publications and source records attributed to G Lenz.

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

How to interpret findings on mortality of long-term lithium treated manic-depressive patients?! Critique of different methodological approaches.

Many studies have shown that patients with affective disorders have a mortality markedly higher than that of the general population. Studies of manic-depressive patients given prophylactic lithium treatment have yielded varying results. Some authors have reported mortalities which were more than four times that of the general population. Others have found mortalities which did not differ significantly from that of the general population. In order to examine these discrepancies we re-analysed the data of a previous study by IGSLI, using three different methods to calculate the Standardised Mortality Ratio (SMR). The data base was enlarged by adding mortality data from two additional centres. The results indicate that the discrepancies may result from the common use of a 'cumulative' approach which produces a distortion of the data if the treatment duration is not taken into consideration properly. An analysis which eliminates this artefact and takes the treatment duration into account ('year-by-year' approach) provides the strongest evidence that the mortality of lithium treated patients is not significantly different from that of the general population.

Adult↗
PubMed1996

[Intubation conditions following administration of atracurium and vecuronium. Bolus method versus priming technique].

Prompted by the ongoing discussion of the pros and cons of using succinylcholine, this study was conducted to compare the responses to bolus injections of atracurium or vecuronium with those after sequential injection of these drugs (priming principle). We evaluated the earliest possible intubation times, intubating conditions, and the onset times (i.e. times from the end of injection to the maximum blockade) under conditions approaching real use as closely as possible. METHODS. The randomized and double-blind study was carried out with 80 ASA risk class 1 and 2 patients. Approval of the institutional ethics committee was obtained, and each patient gave informed consent. Patients were randomly allocated to four study groups of 20 patients each. Isotonic saline was administered to those patients assigned to the atracurium or vecuronium bolus groups, whereas the patients assigned to the other two groups received a priming injection of either atracurium (0.05 mg/kg) or vecuronium (0.01 mg/kg). We observed the patients for signs of incipient muscular weakness before the induction of anaesthesia. Anaesthesia was induced with thiopental 3.5 min after the first injection (5 mg/kg and 50-100 mg before intubation). After a further 1 min during which adequate mask ventilating with oxygen was assured, corresponding to a priming interval of 4.5 min, 0.5 mg/kg of atracurium or 0.1 mg/kg of vecuronium was administered to the patients in the bolus groups and 0.45 mg/kg of atracurium or 0.09 mg/kg of vecuronium as intubating doses to those in the priming groups. Intubation was attempted at 90, 120, 150 and 180 s thereafter. Intubating conditions were evaluated on the basis of laryngoscopy, vocal cord movement and coughing or bucking of the patients. Neuromuscular function was monitored via accelerometry at the adductor pollicis muscle (TOF stimulation of the ulnar nerve every 15 s). RESULTS. The priming doses did not diminish the elicited twitches of the adductor pollicis muscle, but led to heavy eyelids and double vision in 35% of the atracurium patients and 47% of the vecuronium patients; these symptoms were well tolerated by the patients. At the time of intubation the adductor pollicis muscle was relaxed to approximately the same degree in all groups (mean +/- SD for the TOF ratios in the bolus groups was 0.46 +/- 0.37 for atracurium, 0.45 +/- 0.4 for vecuronium; in the priming groups 0.52 +/- 0.39 for atracurium, 0.53 +/- 0.36 for vecuronium). The administration of the relaxants in divided doses significantly shortened the intubating time after atracurium (100 vs 124 s) and improved the intubating conditions of vecuronium (good vs tolerable), but had no effect on the time course of the neuromuscular blockade (onset times in the bolus groups 224 +/- 84 s for atracurium and 209 +/- 64 s for vecuronium; in the priming groups 249 +/- 112 s for atracurium and 205 +/- 52 s for vecuronium). CONCLUSIONS. The priming technique presented here is clinically superior to the bolus method and therefore should be preferred in all elective cases and in those patients in whom succinylcholine is contraindicated.

Adult↗
PubMed1996

Obsessive compulsive disorder and depression--first results of a prospective study on 74 patients.

1. Seventy-four patients who met DSM-III-R criteria for Obsessive Compulsive Disorder received a serotonin reuptake inhibitor and cognitive behavior therapy for 6 months (baseline to follow-up I). 2. In order to maximize therapeutic effects, different kinds of treatment were applied between follow-up I and follow-up II (12 months). 3. Patients were followed-up twice with respect to long-term outcome of obsessive compulsive disorder and depression. Forty % of the sample showed marked improvement at follow-up. No specific variant of treatment could be identified to be significantly more effective. 4. Cross-sectional investigations showed significant correlations between extent of depressive and obsessive compulsive symptomatology (admission, follow-up I and II).

Adolescent↗
PubMed1996

Mortality of patients who dropped out from regular lithium prophylaxis: a collaborative study by the International Group for the Study of Lithium-treated patients (IGSLI).

Excess mortality has repeatedly been found in patients with recurrent affective disorders. In previous studies our group has shown that during long-term lithium treatment the mortality of such patients is not significantly higher than that of the general population. In the present study, we extended our investigation to 273 patients from the earlier IGSLI cohort who subsequently dropped out from regular lithium prophylaxis. The standardized mortality ratio (SMR) for the whole group was 2.5, significantly higher (P < 0.01) than 1.0, which is the SMR of the general population. Furthermore, the SMR of the patients from each of the participating countries, namely Denmark, Germany and Austria, was significantly higher than 1.0. These findings strengthen the evidence accumulated in previous investigations that regular long-term lithium treatment does in fact markedly reduce the excess mortality of patients with recurrent affective disorders.

Antimanic Agents↗
PubMed1996

[Significance of scores for therapy planning and evaluation of individual intensive care patients from the viewpoint of general surgery].

Thirty-six postoperative patients of the department for general, thoracic and vascular surgery were treated in the ICU during November 1995. APACHE-II-Scores were prospectively monitored daily. All three patients with considerable deterioration (> = 2) of this score succumbed. During 6 weeks starting in January 1996 the Hannover-Intensive-Score was documented in all 14 patients requiring ICU-treatment for 3 days or more: three patients died; two without considerable change, one with improvement of this score. Numerical changes of both scores did not precede clinical changes. Thus neither score system replaces or even significantly supports clinical judgement in a field like general surgery with an inhomogenous group of patients.

APACHE↗
PubMed1995

Excess cardiovascular and suicide mortality of affective disorders may be reduced by lithium prophylaxis.

The mortality of patients suffering from affective disorders is much higher than that of the general population; this excess is due to both suicides and cardiovascular disease. During long-term lithium treatment, the overall mortality has not been found to differ significantly from that of the general population but the question remains whether this lowering, if it is in fact caused by lithium, is due to a reduction in suicide frequency or cardiovascular mortality, or both. We analysed data from 827 previously studied patients and used a procedure that estimated both overall mortality and cause-specific mortalities by single-case analysis. For overall mortality, the ratio of observed deaths (among the patients) to expected deaths (in the general population) was 1.14, which is not significantly different from 1.0; this was also found in our previous analysis. In the whole patient group, comprising 5600 patient years under lithium treatment, seven suicides were observed and 1.3 expected, resulting in a standard mortality ratio of 5.22; this is significantly > 1.0, but markedly lower than that found in patients with affective disorders not given lithium. Cardiovascular mortality was not found to be higher in our patients than in the general population. In view of the fact that a placebo-controlled mortality study under long-term conditions is neither ethically nor practically feasible, our findings cannot prove definitively that long-term lithium treatment counteracts factors responsible for the excess suicide and cardiovascular mortality of affective disorders. However, our observations are compatible with such a notion.

Cardiovascular Diseases↗
PubMed1994

[Prolonged neuromuscular blockade. Different antagonistic effects following successive exposure to vecuronium and succinylcholine in a patient with atypical plasma cholinesterase].

An 81-year-old patient had prolonged competitive neuromuscular blockade with train-of-four ratios of 0.1 and 0.5, respectively, after two successive anaesthesia procedures (enflurane-N2O/O2; vecuronium-succinylcholine-sequence) for transurethral prostate resection. Although antagonism with neostigmine was promptly successful after the first, 65-min period of anaesthesia (1.5 mg vecuronium for precurarization, 100 mg succinylcholine for intubation, 3 mg vecuronium), repetitive and chronologically staggered administration of neostigmine after the second, 30-min period of anaesthesia (1 mg vecuronium for precurarization, 100 mg succinylcholine for intubation) had hardly any effect, so that the patient had to be ventilated mechanically for a total of 4.5 h. Laboratory analysis revealed homozygous, atypical, plasma cholinesterase (790 U/l; dibucaine number 23; genotype E1aE1a). This retrospectively confirmed a succinylcholine-induced phase II block in both instances, as had already been suspected following the second anaesthetic procedure. The degree of block transformation, and thus the available time, are decisive in explaining the diverse effects of antagonism here. It must be assumed that a complete phase II block developed after the first succinylcholine exposure owing to the longer duration of anaesthesia; the purely competitive component (train-of-four ratio 0.1) was easily antagonized by neostigmine. At the time of the attempted antagonism after the second, shorter period of anaesthesia, however, block transformation was still incomplete (train-of-four ratio 0.5). The administration of neostigmine therefore rather intensified the depolarization segment of the mixed block, so that repeated attempts at antagonism then inhibited any further block transformation.

Aged↗
PubMed1994

Mortality during initial and during later lithium treatment. A collaborative study by the International Group for the Study of Lithium-treated Patients.

We have previously shown that the mortality of patients with recurrent affective disorders in long-term lithium treatment is not higher than that of the general population. In the present study on 471 patients from Denmark and Germany, we examined mortality during the initial year of lithium treatment and during later lithium treatment. During initial lithium treatment, the total mortality was twice as high as in the general population (difference not significant) and the mortality due to suicide 16 times higher. During later lithium treatment, the mortality rates did not differ from those in the general population. Our results indicate that patients with frequent, often severe recurrences, those chosen for prophylactic lithium treatment, are at risk of high mortality, which then diminishes as the prophylactic action of the treatment takes effect.

Adult↗
PubMed1994

[Modified hemoglobin solutions as artificial oxygen carriers].

At least theoretically, hemoglobin (Hb) solutions are ideal colloidal plasma substitutes because of their unique ability to take up oxygen, transport it in bound form, and release it peripherally. The present study gives an overview of the development and present status of modified Hb preparations. While human and bovine erythrocytes are used for production on the one hand, human Hb variants can also be derived from yeast or bacteria as well as via transgenic animals through recombinant DNA technology. The pronounced limitations of extraerythrocytic Hb, that is its high oxygen affinity and its inadequate intravascular persistence, can be overcome by various modifications. Intravascular half-life of free Hb can be significantly increased by intramolecular stabilization, linking to macromolecules, intermolecular cross-linking (PolyHb solutions) or microencapsulation. Oxygen affinity of human Hb may be lowered by coupling of allosteric modulators to the 2,3-bisphosphoglycerate site, e.g. pyridoxal phosphate, whereas bovine Hb has an intrinsically low oxygen affinity. Human pyridoxylated PolyHb solutions and bovine PolyHb solutions presently fulfill at least 2 of the 3 principal requirements for an oxygen-transporting plasma substitute, i.e. maintenance of the circulating blood volume with provision of additionally utilizable oxygen capacity. Matters of concern with all Hb preparations remain potential vasoconstrictive effects and renal toxicity. Major efforts being undertaken at present by industry and research groups give reason to hope, however, that the concept of modified Hb solutions as oxygen carriers will be realized in the foreseeable future.

Animals↗
PubMed1994

[Nuclear magnetic resonance tomography findings in obsessive-compulsive disorder].

Eighteen patients with a DSM-III-R diagnosis of obsessive-compulsive disorder (OCD) were imaged by MR and compared to a control group of 18 patients with clinically diagnosed unspecific headaches. Weighted spin-echo sequences were carried out with a 1.5T unit in both axial and coronal planes T1 (TR 700/TE 15 ms) and T2 (TR 2500/TE 15.70). The ferritin distributions in the basal ganglia and in the midbrain were evaluated; in addition, the width of the pars compacta in the midbrain on the basis of the criteria of Braffmann et al. 1988, the widths of the inner subarachnoid spaces on the basis of the ventricular index quotient VIQ (TerBrugge, 1986), and the widths of the outer subarachnoid spaces were conducted. The latter was undertaken by three independent investigators whose results were in agreement with one another. In 12 of the OCD patients (n = 18) there was a total of 25 pathological MRI findings; in the control group there were 6 pathological MRI findings in only 6 of the patients (n = 18). In conclusion pathological changes were found at different locations, but a connection between a specific neuroanatomic system and obsessive-compulsive disorder could not be demonstrated.

Adult↗