Disproportional impact of the revised AIDS surveillance definition on the AIDS incidence among drug users compared to homosexual men

The impact of changes in 1993 of the old 1987 WHO/CDC AIDS casedefinition was studied in a cohort of 153 HIV-infected injectiondrug users (IDUs) and 502 HIV-infected homosexual men in Amsterdam.It appeared that the extension in Europe of the old AIDS definitionto also include recurrent pneumonia, pulmonary tuberculosisand invasive cervical neoplasia, strongly increases the numberof persons diagnosed with AIDS among IDUs, but will hardly influencethe AIDS incidence among homosexual men. As recurrent pneumoniaand pulmonary tuberculosis are present among drug users withhigh CD4 cell counts, the incidence of these diseases may partlybe determined by environmental factors. The extension of theold 1987 AIDS definition in the USA with CD4 count <200 cells/mm³In addition to the 3 above-mentioned diseases, will also havea larger impact on drug users than on homosexual men.     

Randomized Evaluation of an Inflatable Femoral Artery Compression Device After Cardiac Catheterization

Mechanical femoral artery compression devices have several limitations. We compared a novel disposable beltheld pneumatic compression device to manual compression alone in 213 patients randomized into two equal groups. Both were comparable for age, gender, current therapy with aspirin (ASA) and warfarin, diameter of the arterial sheath, previous procedures via the same artery, procedure duration, and blood pressure. Manual compression time was 12 ± 3 minutes. Pneumatic compression was reduced during 60 minutes. Patient discomfort was assessed as none (82% vs 88%), mild (13% vs 8%), moderate (3% vs 4%), or severe (2% vs 0%) for the manual versus pneumatic group, respectively. Bleeding and hematoma occurred in 7.5% of patients with no difference between the treatment groups. However, manual compression was significantly more effective in the higher range of systolic blood pressure, and pneumatic in the lower range, with a cut point of approximately 170 mmHg. Predictors for bleeding were systolic blood pressure and dose of ASA. Among 113 patients with systolic blood pressure < 160 mmHg and low dose (75 mg) or no ASA, only / patient (0.9%) experienced bleeding while 31% of 16 patients with both elevated systolic blood pressure and high dose ASA (150–330 mg) bled. We conclude that pneumatic femoral artery compression does not reduce bleeding and hematoma compared with manual compression. The use of low dose (75 mg) or no ASA, as well as giving special attention to patients with elevated systolic blood pressure, may reduce the risk of bleeding after cardiac catheterization .     

Radiofrequency Current Ablation of Porcine Right Atrium: Increased Lesion Size with Bipolar Two Catheter Technique Compared to Unipolar Application In Vitro and In Vivo

Interruption of atrial flutter and fibrillation by RF catheter ablation may be favored by large, elongated lesions. We administered RF current in unipolar and bipolar mode in porcine right atrium. Bipolar ablation was performed between the tip electrodes of two serially coupled catheters. With 4-mm tip electrodes in vitro, lesion length increased from a mean (SD) of 7.9 (1.2) mm at 3 mm-interelectrode distance (IED) to 13.3 (3.3) mm at 9-mm IED, but decreased at 12-mm IED due to nonconfluent lesions (P < 0.0001), With 4 mm distal electrodes and 8 mm IED, bipolar lesions were 65% longer than corresponding unipolar ablations. Switching to bipolar mode increased the lesion length more than increasing electrode tip length to 6 mm in unipolar mode. Power and temperature controlled ablation created equally sized lesions. Twelve anesthetized pigs were randomized to unipolar or two catheter bipolar temperature controlled ablation of the right atrial free wall. Bipolar ablation created confluent lesions with endocardial length × width of 13.5 (5.8) × 7.3 (3.7) mm, unipolar ablation 6.4 (2.8) × 4.6 (1.4) mm (P < 0.001 when comparing length and P = 0.013 for lesion width). The atrial lesions in both groups were transmural and extended into hilar lung lesions with maximal depth of 3.0 (1.1) and 2.6 (1.0) mm, respectively (P = 0.44). Five bipolarly and four unipolarly ablated pigs developed right diaphragmal paresis. We conclude that bipolar ablation may be preferable in situations where large, elongated lesions are favorable. The two catheter technique is feasible in porcine right atrium. Both bipolar and unipolar ablation of the porcine right atrial free wall may frequently be complicated by injury to the phrenic nerve and adjacent lung tissue.     

Radiofrequency Ablation of Symptomatic but Benign Ventricular Arrhythmias

Two cases are presented where ablation of severely symptomatic ventricular arrhythmias not responding to medical therapy was accomplished with radiofrequency current application. After a routine programmed stimulation protocol, a quadripolar ablation catheter with a 4-mm tip was advanced percutaneously into the left ventricle in one case and into the right ventricle in the second case; and after precise pace mapping, the arrhythmogenic focus was successfully ablated using radiofrequency current. The postablation ambulatory recording revealed virtual eradication of ventricular ectopy in both cases. In conclusion, in severely symptomatic cases of "benign" ventricular arrhythmias, radiofrequency ablation offers an effective therapeutic alternative.     

EFFECTS OF THE EXTRADURAL ADMINISTRATION OF MORPHINE OR BUPIVACAINE, ON THE METABOLIC RESPONSE TO UPPER ABDOMINAL SURGERY

The influence of thoracic extradural local anaesthetics (0.5%bupivacaine) or extradural morphine on the metabolic responseto upper abdominal surgery was compared with the administrationof morphine i.v. in the period after operation. The extradurallocal anaesthetic group had significantly lower blood glucoseand plasma FFA concentrations and consistently, but not significantly,lower blood glycerol and lactate concentrations than both theother groups. At 4 h both extradural groups had significantlylower plasma FFA and blood 3-hydroxybutyrate concentrationsthan the control group. Blood alanine concentration decreasedin all three groups with a minimum at 24 h. There were no differencesin serum insulin concentrations between the groups. It is concludedthat thoracic extradural morphine differs from thoracic extradurallocal anaesthetics in being much less able to suppress the metabolicresponse associated with upper abdominal surgery.     

Potency of a Complex Mixture of Polychlorinated Dibenzo-p-dioxin, Dibenzofuran, and Biphenyl Congeners Compared to 2,3,7,8-Tetrachlorodibenzo-p-dioxin in Causing Fish Early Life Stage Mortality

Use of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxicity equivalentsconcentration (TEC) assumes that polychlorinated di benzo-p-dioxins(PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs) act additivelyand via a common mechanism to cause toxicity. To test theseassumptions, 11 TCDD-like congeners and three non-TCDD-likecongeners were combined at ratios typically found in Lake Michiganlake trout. The potency of the mixture, expressed as TEC basedon fish-specific toxic equivalency factors, was compared toTCDD for producing lake trout and rainbow trout early life stagemortality. Signs of toxicity following exposure of newly fertilizedeggs to the mixture or to TCDD were indistinguishable; sac frymortality associated with blue-sac disease, and slopes of thedose-response curves for percentage sac fry mortality versusegg TEC or versus egg TCDD were parallel. However, the mixturedose-response curves were significantly shifted to the rightof the TCDD dose-response curves by 1.3- to 1.8-fold as illustratedby LD₅₀ values. Following exposure to the mixture or TCDD, LD₅₀sfor lake trout early life stage mortality were 97 (89–110)pg TE/g egg and 74 (70–80) pg TCDD/g (LD₅₀, 95% fiduciallimits) and for rainbow trout were 362 (312–406) pg TE/gegg and 200 (148–237) pg TCDD/g egg. These data suggestthat TCDD-like congeners act via a common mechanism to causetoxicity during trout early development, but may not act strictlyadditively when combined in a mixture of TCDD- and non-TCDD-likecongeners at ratios found in Great Lakes fish. The deviationfrom additivity, however, is less than current safety factorsof 10-fold commonly applied in ecological risk assessments,providing support for the continued use of a TE additivity modelfor assessing risk posed by complex mixtures of PCDDs, PCDFs,and PCBs to fish.     

Rasch analysis of the Dutch health assessment questionnaire disability index and the health assessment questionnaire II in patients with rheumatoid arthritis

Objective

The Health Assessment Questionnaire (HAQ) disability index (DI) is the most common self‐reported measure of physical disability in rheumatoid arthritis (RA). Recently, the HAQ‐II was developed in the US as a short, valid, and reliable alternative using Rasch analysis. Our objective was to compare the scaling properties of the HAQ DI and HAQ‐II in Dutch patients with RA.

Methods

We used data from 472 patients with confirmed RA. Internal construct validity of the HAQ versions was assessed using Rasch analysis. Additionally, external construct validity was assessed by examining correlates with other outcome measures.

Results

The HAQ DI had a large floor effect, with 9.5% of the patients indicating no disability compared with 4.3% for the HAQ‐II. Both versions were unidimensional and adequately fit the Rasch model, containing only 1 nonfitting item. Additionally, 2 HAQ‐II items demonstrated overfit and a high residual correlation, suggesting overlap or redundancy in item content. The HAQ‐II demonstrated better item separation, indicating that it covered a wider range of physical function. Item difficulty estimates were reasonably well spread for the HAQ‐II, whereas the HAQ DI items tended to cluster around similar difficulty levels. Both scales contained several items with differential item functioning by sex, age, or disease duration. Both scales demonstrated the expected pattern of correlations with other outcome measures.

Conclusion

The results indicate that both the HAQ DI and HAQ‐II are psychometrically robust measures of physical function. The Rasch‐developed HAQ‐II, however, has several favorable scaling properties, including a better scale length and a reduced floor effect.