No confirmation for a causal role of volume-regulated chloride channels in ischemic preconditioning in rabbits

Volume-regulated chloride channels have recently been proposed to be end-effectors in ischemic preconditioning. The present study attempted to confirm this hypothesis by looking both at cardioprotection and channel activity. In isolated rabbit cardiomyocytes, hypo-osmotic stress (167 mosm/l) induced a current with a magnitude of 2-5 pA/pF at 60 mV. That current could be blocked by the selective chloride channel blockers 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) or indanyloxyacetic acid 94 (IAA-94), but only at 100 microM and 1 m M respectively. Lower concentrations were not effective. Because the channel-blocking concentrations were toxic in isolated perfused rabbit hearts, as evidenced by cessation of cardiac contraction and massive infarction, neither agent could be tested against preconditioning's anti-infarct effect. NPPB and IAA-94 at 1 microM and 10 microM, respectively (the doses used in a previous report), did not affect coronary flow, heart rate and developed pressure, and also did not prevent the infarct size reduction of ischemic preconditioning with 5 min global ischemia/10 min reperfusion preceding 30 min of regional ischemia and 120 min of reperfusion [11. 4(+/-3.6) and (11.1(+/-3.7)% infarction of risk area, respectively]. The volume-regulated chloride and organic osmolyte channel blocker 4, 4;-diisothiocyanostilbene-2,2;-disulfonic acid (DIDS) at 100 microM blocked the hypo-osmotically induced current in myocytes, but again could not be used, since it induced total cessation of cardiac contraction and reduced infarct size in non-preconditioned hearts. Our data do not confirm a prior study on a causal role for volume-regulated chloride channels in the protection of ischemic preconditioning. This hypothesis remains to be adequately tested.

Do out-of-hours co-operatives improve general practitioners' health?

General practitioners (GPs) have been found to have a higher level of anxiety and depression then hospital managers and consultants. In 1995 and 1998, we surveyed GPs in Buckinghamshire. We found that the development of out-of-hours co-operatives was an important factor in the improvement in GPs' health status.

Less afterload sensitivity in short-term hibernating than in acutely ischemic and stunned myocardium

Short-term hibernating myocardium is characterized by reduced contractile function during persistent moderate ischemia, the recovery of metabolic parameters, and the absence of necrosis. To study the afterload dependence of regional wall excursion in short-term hibernating myocardium, in 11 enflurane-anesthetized swine the left anterior descending coronary artery was cannulated and hypoperfused for 90 min to reduce anterior systolic wall thickening (WT, sonomicrometry) by 60%. Under control conditions, at 5 and 90 min ischemia the descending thoracic aorta was acutely constricted to increase left ventricular (LV) pressure by 30 mmHg. Under control conditions, increased LV pressure resulted in decreased WT [i.e., a negative slope of the relationship between WT and LV end-systolic pressure: -11.2 +/- 4.2 (SD) microm/mmHg]. This slope was further significantly decreased at 5 min ischemia (-26.5 +/- 8.8 microm/mmHg) but returned toward control values in short-term hibernating myocardium at 90 min ischemia (-17.2 +/- 6.6 microm/mmHg). At 30 min reperfusion, the slope was once more significantly decreased (-27.8 +/- 8.1 microm/mmHg). In conclusion, WT in short-term hibernating myocardium is less afterload dependent than in acutely ischemic and reperfused myocardium.

Pulmonary edema in patients after liver transplantation

The aim of this study is to determine the incidence of radiological pulmonary edema in elective liver transplant recipients and its relationship to perioperative factors and postoperative course. We reviewed 102 chest radiographs from 34 patients who had undergone orthotopic liver transplantation (OLT). Films were assessed by 2 trained radiologists for evidence of pulmonary edema using a standardized system. Clinical and outcome data from the 34 patients were also recorded. There was a high incidence (47%) of postoperative radiological pulmonary edema that was associated with deterioration in gaseous exchange, elevated pulmonary artery pressure, and increased duration of ventilator dependence and intensive care stay. Eighteen percent of the patients developed edema immediately after surgery, which was associated with greater pulmonary artery pressure and transfusion requirements during surgery. An additional 29% developed edema during the next 16 to 20 hours, but there was no association with fluid replacement. We conclude that pulmonary edema is common after OLT and will influence postoperative recovery in a substantial proportion of transplant recipients. Excess perioperative fluid replacement is unlikely to be the sole mechanism of edema in these patients.

Symbols and their function in managing the anxiety of change: an intersubjective approach

The author suggests that change inevitably creates anxiety because of loss and confrontation with the unknown. It is proposed that one function of symbols is to manage the anxiety of change. They do this by creating a means by which anxieties can be presented to the subject and then communicated to another mind. These creations are called symbolic because, it is proposed, their purpose is the communication as well as the incorporation of internal anxieties and desires with external exigencies, which might be termed symptoms. Viewing them in this way enables the analyst to put symbolic phenomena as they emerge in an analysis into an intersubjective perspective. The author suggests that thinking of symbols as purely intrasubjective phenomena limits our perspective. It is more technically useful to look at the communicative aspects of symbols as they present themselves to the symbolising subject; and, subsequently, to the analyst in the dialogue within the psychoanalytic setting because the objective and temporal dimension of the setting can thereby be included. Two clinical examples of symbols are discussed, one that was brought for analysis and a second that developed in the course of an analysis. One is given as an example of resistance to change, whereas the other revealed an unconscious drive for change.

Group interventions for anger in people with intellectual disabilities

This paper describes an evaluation of a group intervention for reducing inappropriately expressed anger (as aggression) in people with intellectual disabilities. Group intervention was compared to a treatment as usual group consisting of people referred to the group but who had to wait to participate. The intervention used was based on the work of Novaco (1976; 1978) and Benson (1994). However, further modifications to the group that emphasized the contextual perspective of anger, such as the participants being accompanied by a support worker and more collaborative recording procedures, were devised. A reduction in expressed anger and measured levels of depression occurred after group treatment. Reductions in expressed anger were maintained at 6 and 12 months follow up. However, scores on the depression scale tended to increase on follow up. While caution must be expressed when considering these results, this type of intervention shows promise for reducing inappropriately expressed anger in people with intellectual disabilities Suggestions are made for future research and clinical practice.

Molecular aspects of arrhythmias associated with cardiomyopathies

The increased risk of sudden cardiac death in patients with myocardial hypertrophy and heart failure is the result of remodeling that occurs in both the myocyte and interstitial compartments of the heart. Action potential prolongation is a hallmark of hypertrophied and failing myocardium and is a consequence of differential expression and function of membrane currents and transporters. Functional downregulation of K currents in the ventricle is a recurring theme in hypertrophy and failure; the reduction in the density of the transient outward current (I(to)) is the most consistent observation, whereas data on the density of the inward (I(K1)) and the delayed rectifier (I(K)) currents are more contradictory. The altered intracellular Ca handling of the myopathic hearts prolongs the decay of the L-type Ca current and favors extrusion of cytosolic Ca2+ via the Na+-Ca2+ exchanger. The interaction between such altered membrane currents and a changed neurohumoral milieu creates a substrate that is highly susceptible to potentially lethal ventricular arrhythmias.

Extending the indications for curative liver resection by portal vein embolization

AIMS: The aim of ipsilateral portal vein embolization is to induce hypertrophy of normal tissue when resection of a cancerous portion of the liver is contraindicated only by the volume of liver that would remain following surgery. This study reports its use in primary and metastatic liver tumours. METHODS: Eight patients with inoperable liver tumours (three women and five men of median age 68. 5 years; three colorectal hepatic metastases, two cholangiocarcinomas and three hepatocellular cancers) were selected for portal vein embolization. Selected portal branches were occluded distally with microbeads and proximally with coils. Liver volumes were determined by magnetic resonance imaging before embolization and again before surgery, 6-8 weeks later. RESULTS: Embolization was performed successfully in seven patients by the percutaneous-transhepatic route; one further patient required an open cannulation of the inferior mesenteric vein. Management was altered in six patients, who proceeded to 'curative' surgery. The projected remaining (predominantly left lobe) liver volumes increased significantly from a median of 350 to 550 ml (P < 0.05, Wilcoxon matched pairs test). Two patients had disease progression such that surgery was no longer indicated. One patient, whose disease progressed, had the left portal branch occluded unintentionally by a misplaced coil that was successfully retrieved, although the left portal branch remained occluded. CONCLUSIONS: Portal vein embolization produced significant hypertrophy of the normal liver and extended the option of 'curative' surgery to six of the eight patients in whom it was attempted. It appears to be equally effective for primary and metastatic liver tumours in selected patients.

Nebulised steroid in the treatment of croup: a systematic review of randomised controlled trials

BACKGROUND

Croup is one of the commonest respiratory complaints among children. There is growing evidence that steroids may be an effective treatment.

AIM

To assess the effectiveness of treatment with nebulised steroid for children with croup.

METHOD

Systematic review of randomised controlled trials comparing administration of nebulised steroid with placebo. Trials were identified from searches of three bibliographic databases, the Cochrane Controlled Trials Register, correspondence with the manufacturers of nebulised steroid, and one round of manual citation searching.

RESULTS

Eight randomised controlled trials were identified including 574 children with mild to severe croup. Overall, the mean age was 25.2 months and 72% of children were male. All trials were hospital-based and of good methodological quality, with adequate concealment of treatment allocation and blind outcome assessment. Children treated with nebulised steroid were significantly more likely to show an improvement in croup score by five hours (combined relative risk = 1.48, 95% confidence interval [CI] = 1.27 to 1.74) and significantly less likely to need hospital admission after attending the emergency department (combined relative risk = 0.56, 95% CI = 0.42 to 0.75) than the placebo group. The funnel plot indicated the presence of publication bias, with smaller studies showing the larger effects, but this could also be owing to less pronounced effects in studies of older children with milder croup.

CONCLUSIONS

Nebulised steroids are effective in the treatment of children attending hospital departments with croup. A meta-analysis based on individual patient data could clarify to what extent the effect depends on age and severity of disease. New trials are needed to define the indications for, and effectiveness of, steroid treatment of croup in the community.

Simultaneous X-Ray and TeV Observations of a Rapid Flare from Markarian 421

Mrk 421 was observed for about 2 days with BeppoSAX in 1998 April as part of a worldwide multiwavelength campaign. A large, well-defined flare was observed in X-rays. The same flare was observed simultaneously at TeV energies by the Whipple Observatory gamma-ray telescope. These data provide (1) the first evidence that the X-ray and TeV intensities are well correlated on timescales of hours and (2) the first exactly simultaneous X-ray and TeV spectra. The results imply that the X-ray and TeV photons derive from the same region and from the same population of relativistic electrons. The physical parameters deduced from a homogeneous synchrotron self-Compton model for the spectral energy distribution yield electron cooling times close to the observed variability timescales.

Preparation and preliminary study of crystals of the recombinant calcium-regulated photoprotein obelin from the bioluminescent hydroid Obelia longissima

Crystals of recombinant obelin, the Ca(2+)-regulated photoprotein from the marine hydroid Obelia longissima, have been grown from sodium citrate solutions. Crystals grow as hexagonal light-yellow rods (0.1 x 0.1 x 1.0 mm) which diffract to beyond 1.8 A with synchrotron radiation of 1.0 A wavelength. The crystals have a primitive hexagonal lattice with unit-cell parameters a = 81.55, c = 86.95 A. The asymmetric unit contains two molecules. This represents the successful preparation of single crystals of a photoprotein obelin which have promising diffraction properties.

Role of prolactin in regulating the onset of winter fur growth in mink (Mustela vison): A reconsideration

The objectives of this study were to determine: (1) if the onset of winter hair growth (anagen) in mink could be delayed or inhibited by elevating endogenous PRL concentrations; (2) if bilaterally adrenalectomy (ADX)-induced winter anagen occurs concomitantly with a reduction in serum PRL concentrations, and (3) if exogenous dehydroepiandrosterone (DHEA), an adrenal steroid or Delta(5)-DIOL (a peripherally produced metabolite of DHEA), would delay or inhibit the onset of winter anagen. During early July, while in the resting (telogen) stage of the hair growth cycle, mink were treated with slow release implants containing haloperidol (HAL, a dopaminergic antagonist), melatonin (MEL), deoxycorticosterone (DOC), DHEA and Delta(5)-DIOL. In addition, mink were ADX'd and supplemented with DOC and DHEA. MEL reduced PRL levels to basal levels and induced winter anagen 7 weeks earlier than controls. Surprisingly, HAL initiated winter anagen 7 weeks earlier than controls (P < 0.05), although serum PRL levels were not different between the two groups. Mink that were ADX'd or ADX + DHEA-treated exhibited winter anagen 6 weeks earlier than controls (P < 0.05), but serum PRL concentrations were not different between the three groups. The administration of DHEA or Delta(5)-DIOL to mink with intact adrenals had no effect on the time of onset of winter anagen or serum PRL levels. Our findings suggest that a reduction in circulating PRL levels is not essential for onset of winter anagen in the mink and that the apparent inhibitory effects of the adrenal glands on initiation of winter anagen is not mediated through DHEA or its metabolite Delta(5)-DIOL. J. Exp. Zool. 284:437-444, 1999.

Electromyographic differentiation of diplegic cerebral palsy from idiopathic toe walking: involuntary coactivation of the quadriceps and gastrocnemius

Clinical differentiation of patients with mild diplegic cerebral palsy (CP) and idiopathic toe walking (ITW) can be difficult. However, an involuntary extensor pattern may be a distinguishing sign. The purpose of this study was to determine if selected gait parameters or patterns of electromyogram (EMG) timing of quadriceps, gastrocnemius, and tibialis anterior during knee extension while sitting can distinguish between these patients. The hypothesis was that EMG testing for selective control of the quadriceps and gastrocnemius could differentiate patients with diplegic CP from normal controls and from patients with ITW. We evaluated 10 control, eight CP, and eight ITW subjects. Measurements included walking speed, energy expenditure index (EEI), ankle position during stance, and EMG of the quadriceps, gastrocnemius, and tibialis anterior during gait and during knee extension while sitting. Dynamic EMG timing during gait showed significant differences in the mean onset of the gastrocnemius between subjects with CP and ITW, but there was considerable overlap. More consistent differences were found during active and active-resisted knee extension while sitting. Mean values for gastrocnemius EMG timing recorded as a percentage of duration of quadriceps EMG while sitting were 0 and 0.4% for controls, 0 and 3.9% for ITW subjects, and 84.3% and 93.4% for CP subjects. Patterns of EMG timing of the quadriceps and gastrocnemius during knee extension while sitting can help to differentiate patients with mild diplegic CP from those with ITW.

Suicide in Auckland 1989 to 1997

AIM

The aim of this study was to describe the population of people who had committed suicide in Auckland in the nine years, 1989 to 1997.

METHODS

We extracted data from the police records to the coroner and the autopsy reports on people who had killed themselves in the Auckland coronial region.

RESULTS

Suicide is common and disproportionately affects young men, the unemployed and sickness beneficiaries. Few people who kill themselves appear to be in contact with the mental health services.

CONCLUSIONS

For effective prevention, up to date local information on suicide and deliberate self-harm is needed.

Stress and residential staff who work with people who have an intellectual disability: a factor analytic study

The present study describes the development of a questionnaire, and the subsequent collection of data, to gather information on the demands and supports which influence stress (as measured by anxiety and depression scales) in direct care staff who work with people with intellectual disability. The results from the questionnaire were also used to explore the relationships between the factors derived from the questionnaire and to consider how these may be influential in building organizational models. The questionnaire was specifically constructed to measure the demands and supports experienced by direct care staff. The participants included 216 staff working in community residential services for people with intellectual disability. These individuals included staff working for two British health trusts and similar staff working for one local authority. The questionnaire consisted of 33 demands items and 23 supports items. Separate factor analyses were conducted on the demands and supports scales. Analyses of the reliability and validity of the resulting factors were conducted. Stepwise multiple regressions were conducted to further explore the relationship of factors with the measures of anxiety and depression. Four factors were extracted from the demands scale and three factors from the support scale. There was some concern over levels of reliability and validity for individual factors; however, the reliability of the main scales appeared to be satisfactory. All but one support factor correlated significantly with levels of anxiety and depression. The factors explained a modest amount of the variance in the regressions. While there are some concerns about the psychometric properties of the questionnaire, it is argued that the scales and factors can be used to confirm and further understanding of the relationship between groups of demands, supports and stress in staff. The usefulness of the questionnaire as a means of diagnosing specific sources of demand and support is considered. It is suggested that the questionnaire could form the basis for assessment and subsequent intervention in houses where staff are reporting relatively high levels of anxiety and depression.

Laparoscopic colorectal anastomosis: risk of postoperative leakage. Results of a multicenter study. Laparoscopic Colorectal Surgery Study Group (LCSSG)

BACKGROUND

We report on a prospective observational multicenter study of more than 1,000 consecutive patients undergoing laparoscopic colorectal procedures. The aim of the current study was to investigate the safety of laparoscopic colorectal surgery as reflected by the anastomotic insufficiency rates in the various sections of the bowel, and to compare these rates with those of open colorectal surgery.

METHODS

The study was begun on August 1, 1995. Twenty-four centers in Germany, Austria, and Switzerland participated in this prospective multicenter study. All patients undergoing laparoscopic colorectal surgery were included in the study. No selection criteria were applied, which means that every operation begun as a laparoscopic procedure was included. Data on patient demographics, surgical indications, surgical course, and patient outcome were recorded prospectively in a computer database. All data were rendered anonymous.

RESULTS

Between August 1995 and February 1998, the 24 participating centers treated 1,143 patients (male/female ratio, 1:1.36; mean age, 60.7 years). In all, 626 operations were performed for benign indications and 517 for cancer. Most procedures involved the sigmoid colon and rectum (80.9%). An anastomosis was performed in 83% of the operations. Most of the anastomoses were laparoscopically assisted using the stapling technique. We observed an overall leakage rate of 4.25% (colon 2.9%; rectum 12.7%), and surgical reintervention was required in 1% of the cases. The rate of conversion to open surgery was 5.6%. Intraoperative complications occurred in 5.9%, and reoperation was necessary in 4.1% of the cases. The overall morbidity rate was 22.3%, and the 30-day mortality rate was 1.57%.

CONCLUSIONS

The feasibility and safety of the laparoscopic colorectal approach is demonstrated clearly. The current study shows that the laparoscopic or laparoscopically assisted approach to colorectal surgery is not associated with a higher risk of anastomotic leaks. Morbidity and mortality rates with this method approximate those seen with conventional colorectal surgery.

Ethambutol-sugar hybrids as potential inhibitors of mycobacterial cell-wall biosynthesis

Ethambutol is an established front-line agent for the treatment of tuberculosis, and is also active against Mycobacterium avium infection. However, this agent exhibits toxicity, and is considered to have low potency. The action of ethambutol on the mycobacterial cell wall, particularly the arabinan, and comparison of the structure of ethambutol with several of the cell-wall saccharides, suggested that ethambutol-saccharide hybrids might lead to agents with a more selective mechanism of action. To this end, eight ethambutol-saccharide hybrids were synthesized and screened against M. tuberculosis and several clinical isolates of M. avium.