Modification of Atrioventricular Conduction Using a Combined Laser-Electrode Catheter

Ablation of the AV junction is an accepted technique for the management of selected supraventricular tachyarrhythmias. Radiofrequency ablation appears to be safe and effective for AV junction ablation in most patients, but the need for firm tissue contact may make it less effective for ventricular tachycardia and certain ectopic atrial tachycardias. Laser energy can also be delivered through a catheter, and thus it may be an attractive alternative energy source for ablation. A new laser-electrode catheter was developed for modification of conduction through the AV node as a model for ablation of an arrhythmia substrate. A window for delivery of continuous-wave Nd:YAG laser energy was placed between the two electrodes of a bipolar electrode catheter. In vitro studies using a matrix of power versus time were performed to determine the energy that would create lesions of the appropriate size in vivo. Using this information, advanced AV block was successfully created in 16 of 17 dogs (94%) with the laser-electrode catheter. Advanced AV block was successfully created in all four dogs in the chronic study, and it persisted for 1-24 weeks of follow-up until sacrifice of the animals. Histologic examination demonstrated discrete thermal damage at the AV junction with no instances of septal perforation in the acute studies or progressive necrosis in chronically maintained dogs. Advanced AV block may be produced consistently and safely in dogs using a combined laser-electrode catheter.     

Understanding the pathogenesis of type 2 diabetes: can we get off the metabolic merry-go-rounds?

The aetiology of non-insulin-dependent diabetes mellitus (NIDDM) is not known. The concordance of NIDDM in identical twins and differences in the prevalence rate of NIDDM between different racial groups suggest a genetic cause. Hyperglycaemia in established diabetes is caused by a combination of hepatic insulin resistance, impaired peripheral (muscle and fat) glucose uptake and a defect in glucose-mediated insulin secretion. However, it is not known if these defects are all inherited or if one can cause the others. This uncertainty is due to the fact that hyperglycaemia per se can cause defects in insulin action and insulin secretion that resemble those found in NIDDM. Furthermore the elevated free fatty acid (FFA) levels found when NIDDM is associated with obesity are known to cause both peripheral and hepatic insulin resistance. Recently we have demonstrated the mechanism by which elevated FFA levels can cause hepatic insulin resistance. However, we also have evidence that the converse holds in that genetically engineered hepatic insulin resistance in a transgenic rat model leads to obesity. Thus an understanding of the pathogenesis of NIDDM is complicated by the fact that hyperglycaemia and obesity can be both causes and consequences of insulin resistance. To overcome these difficulties, studies in young, euglycaemic diabetes-prone subjects have been conducted. Results suggest that there may be different causes for NIDDM in different racial groups.     

Sensitivity of Entamoeba histolytica and Entamoeba dispar patient isolates to human complement

Twenty-one Entamoeba histolytica and 56 Entamoeba dispar patient isolates were investigated for their sensitivity to the classical and alternative pathway of human complement. E. histolytica and E. dispar patient isolates were differentiated by polymerase chain reaction and hexokinase isoenzyme typing. It was found that 90.3% (±12.0%) of the trophozoites of E. histolytica were lysed after 30 min by the alternative pathway of complement in the presence of 50% human serum (19 isolates showed lysis rates higher than 80%), whereas E. dispar cells were less susceptible to the alternative pathway as 68.8% (±28.2%) of lysis occurred. However, 23 of the E. dispar isolates were lysed between 100 and 80% (90.9%±9.1%), demonstrating that about half of the tested E. dispar isolates were highly sensitive to complement lysis. Only 11 of the E. dispar isolates were proven to be 'resistant' to the alternative pathway of complement and were lysed less than 40%. These results are in conflict to earlier publications, describing resistance of E. dispar to complement lysis (Hamelmann et al. 1992, 1993).     

Pain and the administration of analgesia: what nurses say

? Pain of moderate to severe intensity continues to be an important problem for many hospitalized patients. ? Nurses spend more time with patients than any other health professional group and have a key role to play in the management of patients' pain. ? This paper reports the findings from a series of focus group interviews which were undertaken to explore nurses' perceptions regarding pain and the administration of narcotic analgesia. ? Themes identified from participants' comments related to (1) the pivotal role of nurses in pain management; (2) nursing assessment and pain management decisions (3) individual factors influencing nurses' pain management decisions and (4) the influence of others on nurses' pain management decisions. ? These findings have implications for further research and the development of innovative educational strategies.     

Propafenone-Induced Torsade de Pointes: Cross-Reactivity with Quinidine

A 77-year-oid/emale with new onset atrial fibrillation occurring in the absence of structural heart disease developed torsade de pointes during therapy with quinidine bisulfate 500 mg orally every 8 hours. Ten days after quinidine therapy had been discontinued she developed torsade de pointes while receiving propafenone 300 mg orally every 8 hours. This case demonstrates that propafenone may be associated with torsade de pointes and suggests a cross-reactivity between this effect and prior occurrence of torsade de pointes on Class IA antiarrhythmic drug therapy.     

Clonogenic Patterns of Human Pulmonary Adenocarcinoma Cell Lines (PC-9, PC-13 and PC-14) and How They Influence the Results of Test for Chemosensitivity to Cisplatin in the Human Tumor Clonogenic Assay

The clonogenic patterns of three human pulmonary adenocarcinomacell lines (PC-9, PC-13 and PC-l4) were studied by human tumorclonogenic assay (HTCA), and factors which could influence theresults of tests for the chemosensitivity of these tumor cellsto cisplatin in HTCA were determined. The results showed thateach tumor cell line had a characteristic clonogenic pattern.The time intervals for the cells to grow to the plateau phasevaried from 9 to 16 days, depending on the cell line and numberof cells plated. The number of cells plated could substantiallyinfluence the results of chemosensitivity tests. The percentageof surviving colonies increased markedly if too many cells (usually5 x 10⁴ or more/plate) were plated. For continuous exposure,the results of chemosensitivity tests were rather stable after7 days of incubation in each cell line, especially when fewerthan 2 x 10⁴ cells/plate were plated. For 1-hour exposure, theincubation periods for the results to become stable varied from7 to 16 days depending on the cell type, number of cells platedand drug concentration. It was stressed that for the correctevaluation of the chemosensitivity of cultured cell lines inHTCA, the clonogenic pattern of each tumor cell line shouldbe checked in detail before further experiments are conducted.The higher the concentration and the longer the exposure time,the more strongly cis-diamminedichloroplatinum (CDDP) suppressedthe colony growth in each of the three cell lines in HTCA, andit was recommended that CDDP should be used clinically in sucha way as to maintain a high serum level of the active form ofCDDP for a long time.     

HYPOTHALAMIC HORMONE INTERACTION IN ACROMEGALY

The growth hormone response to the administration of the currently available synthetic hypothalamic hormones was assessed in eleven patients with acromegaly. Eight of them showed a positive GH response to thyrotrophin releasing hormone and three showed no response. The GH response to TRH was shown to be unrelated to the thyrotrophin response to TRH. The GH response to TRH was inhibited by the administration of growth hormone release inhibiting hormone. Luteinizing hormone/follicle stimulating hormone releasing hormone (LHRH) caused a positive GH response in four patients, but this was trivial in three. The TRH mediated GH release in acromegaly is not mediated via TSH and appears to be attributable to loss of specificity of the receptor sites on the somatotroph to the hypothalamic hormones.     

Intellectual disability: population‐based estimates of the proportion attributable to maternal alcohol use disorder during pregnancy

Aim The aim of this study was to examine the association between maternal alcohol use disorder and intellectual disability in children. Method All mothers with an International Classification of Diseases (ICD) 9 and/or 10 alcohol‐related diagnosis, a proxy for alcohol use disorder, recorded on the Western Australian health, mental health, and drug and alcohol data sets were identified through the Western Australian Data Linkage Unit (n=5614 non‐Aboriginal; n=2912 Aboriginal). A comparison cohort of mothers without an alcohol‐related diagnosis was frequency matched on maternal age within maternal Aboriginal status and year of birth of their children. Linkage with the Western Australian Midwives Notification System (1983–2001) identified all births to these mothers (n=10 664 and 7907 respectively). Linkage to the Western Australian Intellectual Disability Database and Register of Developmental Anomalies identified cases of intellectual disability with no identified genetic origin (intellectual disability) (n=1487) and fetal alcohol syndrome (n=66). Odds ratios (ORs) and 95% confidence intervals (CIs) for intellectual disability were calculated using logistic regression incorporating generalized estimating equations and used to estimate population‐attributable fractions. Results At least 3.8% (95% CI 2.84–4.89%) of cases of intellectual disability could be avoided by preventing maternal alcohol use disorder: 1.3% (95% CI 0.81–1.86%) in non‐Aboriginal and 15.6% (95% CI 10.85–20.94%) in Aboriginal children. We observed a three‐fold increase in the adjusted odds of intellectual disability in children of mothers with an alcohol‐related diagnosis recorded during pregnancy (non‐Aboriginal OR 2.89, 95% CI 1.62–5.18; Aboriginal OR 3.12, 95% CI 2.13–4.56), with a net excess proportion of 3.7% and 5.5% respectively. One‐third (32%) of children diagnosed with fetal alcohol syndrome had intellectual disability. Interpretation Maternal alcohol use disorder is the leading known risk factor for intellectual disability with no identified genetic origin.     

Factors associated with caregivers' perception of children's health and oral health status: a study of 6- to 36-month-olds in Uganda

Background.  The impact of oral diseases on quality of life of children and their families has not been thoroughly investigated.
Aim.   Focusing on Ugandan infants aged 6–36 months and their caregivers, this study examined the degree to which clinical and psychosocial factors were associated with caregivers' overall evaluation of their children's oral health and health status.
Design.  Eight hundred and sixteen children were examined for dental caries and anthropometric status in 2007. A questionnaire was completed by the caregivers.
Results.  Poor child oral health was reported by 40.2% and 17.5% of caregivers who reported their children's health as, respectively, poor and good. Having the least family wealth [odds ratio (OR) = 1.9] and reporting distressed family activities (OR = 2.3) were associated with higher odds of reporting poor child oral health, whereas being a rural resident (OR = 0.4) and reporting no symptoms during tooth eruption (OR = 0.3) were associated with lower odds. Perception of poor child oral health (OR = 2.8) and having the least family wealth (OR = 1.7) were associated with higher odds of reporting poor child health status, whereas no stunting was associated with lower odds (OR = 0.5).
Conclusion.  The results support the growing recognition of oral health as a predictor of health and well-being in early childhood.