Molecular Interaction of Droperidol with Human Ether-a-go-go-related Gene Channels: Prolongation of Action Potential Duration without Inducing Early Afterdepolarization

Background: The cardiac safety of droperidol given at antiemetic doses is a matter of debate. Although droperidol potently inhibits human ether-a-go-go-related gene (HERG) channels, the molecular mode of this interaction is unknown. The role of amino acid residues typically mediating high-affinity block of HERG channels is unclear. It is furthermore unresolved whether droperidol at antiemetic concentrations induces action potential prolongation and arrhythmogenic early afterdepolarizations in cardiac myocytes.

Methods: Molecular mechanisms of HERG current inhibition by droperidol were established using two-electrode voltage clamp recordings of Xenopus laevis oocytes expressing wild-type and mutant channels. The mutants T623A, S624A, V625A, Y652A, and F656A were generated by site-directed mutagenesis. The effect of droperidol on action potentials was investigated in cardiac myocytes isolated from guinea pig hearts using the patch clamp technique.

Results: Droperidol inhibited currents through HERG wild-type channels with a concentration of half-maximal inhibition of 0.6-0.9 [mu]m. Droperidol shifted the channel activation and the steady state inactivation toward negative potentials while channel deactivation was not affected. Current inhibition increased with membrane potential and with increasing duration of current activation. Inhibition of HERG channels was similarly reduced by all mutations. Droperidol at concentrations between 5 and 100 nm prolonged whereas concentrations greater than 300 nm shortened action potentials. Early afterdepolarizations were not observed.     

The Combination of Exercise and Respiratory Training Improves Respiratory Muscle Function in Pulmonary Hypertension

Purpose

Increased dyspnea and reduced exercise capacity in pulmonary arterial hypertension (PAH) can be partly attributed to impaired respiratory muscle function. This prospective study was designed to assess the impact of exercise and respiratory training on respiratory muscle strength and 6-min walking distance (6MWD) in PAH patients.

Methods

Patients with invasively confirmed PAH underwent 3 weeks of in-hospital exercise and respiratory training, which was continued at home for another 12 weeks. Medication remained constant during the study period. Blinded observers assessed efficacy parameters at baseline (I) and after 3 (II) and 15 weeks (III). Respiratory muscle function was assessed by twitch mouth pressure (TwPmo) during nonvolitional supramaximal magnetic phrenic nerve stimulation.

Results

Seven PAH patients (4 women; mean pulmonary artery pressure 45 ± 11 mmHg, median WHO functional class 3.1 ± 0.4, idiopathic/associated PAH n = 5/2) were included. The training program was feasible and well tolerated by all patients with excellent compliance. TwPmo was I: 0.86 ± 0.37 kPa, II: 1.04 ± 0.29 kPa, and III: 1.27 ± 0.44 kPa, respectively. 6MWD was I: 417 ± 51 m, II: 509 ± 39 m, and III: 498 ± 39 m, respectively. Both TwPmo (+0.41 ± 0.34 kPa, +56 ± 39 %) and 6MWD (+81 ± 30 m, +20 ± 9 %) increased significantly in the period between baseline and the final assessment (pairwise comparison: p = 0.012/<0.001; RM-ANOVA considering I, II, III: p = 0.037/<0.001).

Conclusions

Exercise and respiratory training as an adjunct to medical therapy may be effective in patients with PAH to improve respiratory muscle strength and exercise capacity. Future, randomized, controlled trials should be carried out to further investigate these findings.     

Quality control in ambulatory health care. Results of an area-wide study by the public medical service of the Baden-Württemberg health insurance

Discussions surrounding the quality of nursing care, fueled by recurring press reports, prompted the State Nursing Insurance Associations in Baden-Wuerttemberg to request the Health Insurance Medical Service to perform a quality control of outpatient nursing care services in the state. Based on a coordinated concept and for the first time in the Federal Republic of Germany, all authorized ambulatory institutions area-wide were subjected to a uniform assessment (total survey) during an official inquiry time period. The end results of these controls failed to verify the judgement often propagated by the press based on individual cases that high-quality nursing care can no longer be afforded under the present circumstances. On the average, 55% of the personnel provided to patients by outpatient nursing services were health care professionals. What is more, this professional staff rendered 75% of all nursing care services. The evaluation of the accompanied medical visits indicated that the vast majority attempted to take active nursing care into account. With regard to quality assurance, a great optimisation potential was indicated primarily in the area of nursing documentation. Only in about 35% of the nursing documents inspected was the nursing procedure always clearly evident. A future problem could arise from the fact that of all nursing professionals with leadership responsibilities, at the time of the survey only about 37% had completed the requisite professional training qualification programme of 460 training hours. If the time before the interim deadline (March 31, 2002) is not utilised, the institutions in question could face consequences that could threaten their very existence. It is evident that a large number of outpatient nursing care services in the state of Baden-Wuerttemberg do not have their economic foundation in the domain of the Nursing Care Insurance Law, which affects both patient structure and care intensity. As a consequence, there is no quality control or inspection whatsoever for the majority of nursing care services rendered by ambulatory nursing care services at present because they are not under the jurisdiction of the German Federal Social Legislation SGB XI.     

Indocyanine green angiography in Fundus flavimaculatus

PURPOSE: To describe the characteristic findings of fundus flavimaculatus (Stargardt disease) as seen on indocyanine green angiography. METHODS: Twelve eyes of 6 consecutive patients with fundus flavimaculatus were studied by fundus color photographs, fluorescein angiography and indocyanine green angiography. RESULTS: Indocyanine green angiography allowed visualization of small, clearly demarcated areas in which hypofluorescence increased over time, leading eventually to a large reticular pattern with small areas of normal-appearing choroid encircled by a well-defined network of hypofluorescent curvilinear lesions. These hypofluorescent flecks were present in all 12 eyes but corresponded only partially to the yellow flecks visible on biomicroscopy of the fundus. The peripapillary area was well preserved on indocyanine green angiography and the periphery did not show any visible abnormalities. CONCLUSIONS: The hypofluorescent curvilinear areas visualized on indocyanine green angiography form a reticular pattern that is similar to the polygonal shape of the watershed zones between terminal choroidal arterioles, which supply the choriocapillaris. These dark areas may reflect choriocapillaris defects secondary to lysis of lipofuscin-engorged retinal pigment epithelial cells. The typical lesions of fundus flavimaculatus thus seem to be situated in areas of least vascular supply. Their absence in the peripapillary area, which benefits from anastomotic vascular connections, would support this hypothesis.     

Retinal vessel autoregulation in sickle cell patients

We tested retinal vessel autoregulation in 16 sickle cell patients and 6 controls by computer-assisted measurements of constriction of the superior and inferior temporal veins and arteries after pure oxygen breathing. Compared to the controls and corrected for age, we found a decrease of vasoconstriction in three of the four vessels measured in the sickle cell group, which was statistically significant only for the superior temporal artery (P 0.009). The number of patients was too small to allow a separate analysis of possible contributary factors within the sickle cell group, such as sickle cell hemoglobin subtype and extent of retinal ischemia. Our findings indicate a factor not yet well known in the pathophysiology of sickle cell disease: an abnormality of local microvascular control.Presented in part at the ARVO meeting in Sarasota, Fl, 30 April 1990     

Use of nonprohibited hallucinogenic plants: increasing relevance for public health? A case report and literature review on the consumption of Salvia divinorum (Diviner's Sage)

INTRODUCTION:: We want to call attention to a mint plant, called diviner's sage ( Salvia divinorum), originally used in shamanic ceremonies of the Mazatec Indians of Mexico. On numerous websites of the internet, this ancient herbal drug and its extracts are offered as a legal means of widening individual awareness. Regarding its dose-response relationship, the active ingredient, salvinorin A, is one of the most potent naturally occurring hallucinogens. Laws on controlled substances, except for Finland, Denmark and Australia, do not prohibit cultivating, consuming or dealing with Salvia divinorum. Ingestion by smoking, vaporising or chewing, induces a short-lived inebriant state with intense, bizarre feelings of depersonalization. This article wants to be a signal for physicians or psychotherapists to take Salvia into consideration, when exploring young people for drug use. METHODS: We report the individual perceptions of a young man consuming Salvia divinorum. We review the scarce scientific literature and consider relevant internet websites. DISCUSSION: We define open issues for further investigations and try to discuss why Salvia divinorum may be of interest for teenagers and young adults in Europe.     

Ergonomic office design and aging: a quasi-experimental field study of employee reactions to an ergonomics intervention program

A naturally occurring quasi-experimental longitudinal field study of 87 municipal employees using pretest and posttest measures investigated the effects of an office workstation ergonomics intervention program on employees' perceptions of their workstation characteristics, levels of persistent pain, eyestrain, and workstation satisfaction. The study examined whether reactions differed between younger and older employees. Results revealed that workstation improvements were associated with enhanced perceptions of the workstation's ergonomic qualities, less upper back pain, and greater workstation satisfaction. Among those experiencing an improvement, the perceptions of workstation ergonomic qualities increased more for younger than older employees, supporting the "impressionable years" framework in the psychological literature on aging. Implications for human resources managers are discussed.     

Ten Years of Treatment with 400 mg Imatinib per Day in a Case of Advanced Gastrointestinal Stromal Tumor

Imatinib mesylate, as treatment for gastrointestinal stromal tumors (GIST), has dramatically changed the prognosis for survival - not only because it is efficacious, but also because it attracted attention to this malignant disease. GIST is now a well-known disease entity and a paradigm for targeted therapies in malignant diseases. A now 74-year-old patient presented with recurrence of a primary duodenal GIST (initial diagnosis and primary resection in 1998; diameter 10 cm, KIT exon 11 mutation, PM V559D) and liver metastasis after a second surgical resection was performed in 2000. Conventional chemotherapy with adriamycin and ifosfamide failed to control growth of the relapsed tumor and liver metastasis. In July 2001, compassionate use of imatinib was started. Tumor regression was observed at continuous follow-ups (every 2 months for the first 6 months, and 6 months thereafter) and persisted until now. The patient's physical performance has remained in good condition. Side effects consisted of periorbital edema and sudden muscle cramps of toes and fingers, pain of bones and joints, an intentional tremor, a paler color of the skin, as well as a slight anemia. Imatinib is the first orally administered anticancer drug. Our case shows that a sustained response is possible with continuous therapy over a long time, if the drug is well tolerated. This implies a high compliance of the patient and suggests that resistance to imatinib does not have to develop. Exon 11 (point) mutation might not only represent a positive predictor for imatinib response in general, but especially for imatinib response on long-term.     

Impairment of respiratory muscle function in pulmonary hypertension

It has been suggested that impaired respiratory muscle function occurs in patients with PH (pulmonary hypertension); however, comprehensive investigations of respiratory muscle function, including the application of non-volitional tests, needed to verify impairment of respiratory muscle strength in patients with PH have not yet been performed. In the present study, respiratory muscle function was assessed in 31 patients with PH (20 females and 11 males; mean pulmonary artery pressure, 51+/-20 mmHg; median World Health Organization class 3.0+/-0.5; 25 patients with pulmonary arterial hypertension and six patients with chronic thromboembolic PH) and in 31 control subjects (20 females and 11 males) well-matched for gender, age and BMI (body mass index). A 6-min walking test was performed to determine exercise capacity. Volitionally assessed maximal inspiratory (7.5+/-2.1 compared with 6.2+/-2.8 kPa; P=0.04) and expiratory (13.3+/-4.2 compared with 9.9+/-3.4 kPa; P<0.001) mouth pressures, sniff nasal (8.3+/-1.9 compared with 6.6+/-2.2 kPa; P=0.002) and transdiaphragmatic (11.3+/-2.5 compared with 8.7+/-2.5 kPa; P<0.001) pressures, non-volitionally assessed twitch mouth (1.46+/-0.43 compared with 0.97+/-0.41 kPa; P<0.001) and transdiaphragmatic (2.08+/-0.55 compared with 1.47+/-0.72 kPa; P=0.001) pressures during bilateral anterior magnetic phrenic nerve stimulation were markedly lower in patients with PH compared with control subjects. Maximal inspiratory mouth (r=0.58, P<0.001) and sniff transdiaphragmatic (r=0.43, P=0.02) pressures were correlated with the 6-min walking distance in patients with PH. In conclusion, the present study provides strong evidence that respiratory muscle strength is reduced in patients with PH compared with well-matched control subjects. Furthermore, the 6-min walking distance is significantly linked to parameters assessing inspiratory muscle strength.