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In a recently conducted case-control study of sporadic cryptosporidiosis, 6.6% of subjects in the control group reported having had diarrhea in the 2 weeks before completion of the questionnaire. In an analysis of this control group, there was a very strong association between self-reported diarrhea and reported low water pressure at the faucet.
Report about part--results of a longterm follow-up--study with 123 sixteenged risk--children, which were treated with an exchange transfusion because of hemolytic disease in newborn age. The control group was paralleled to social--demographic criteria. Before all biological and social factors of influence the parental education and qualification level was the most influential social determinant on the development of intelligence and school-achievement. 33,3% of the risk group and 15,5% of the control group did not reach the 10th form of the polytechnical school according to their age.
The increase in life expectancy within the general population has resulted in an increasing number of elderly adults with intellectual disability, and this is reflected in the increased life expectancy in persons with Down syndrome, currently about 56 years. The aim of this study was to study the clinical characteristics, the functional status and sensori-motor function of 10 older persons with Down syndrome (mean age 59 years), 13 younger persons with Down syndrome (mean age 44 years) and compare them with 38 adults with intellectual disability without Down syndrome and a control group of people without intellectual disability. All the persons with Down syndrome and intellectual disability resided in two residential living centres in Israel, while the 31 older persons without intellectual disability (mean age 75 years), who served as the control group, lived in an independent living facility. The study considered demographic data, medical backgrounds, physical and functional tests. The results showed that the older persons with Down syndrome in the study were more obese, shorter and had more medical problems than both the older persons with intellectual disability and the control group. The functional performance of the older adults with Down syndrome was more impaired in comparison with both other groups. It is postulated that their slower responses may be explained by a less physically active lifestyle, that may accelerate the onset of disease, resulting in symptoms associated with aging that are detrimental to health.
BACKGROUND AND PURPOSE: Our aim in this study was to investigate the relation between chronic alcohol consumption and stroke. METHODS: A case-control study was carried out using two hospital-based control groups and the results of a community-based survey of alcohol consumption. Hospital-based control subjects were chosen either from "general" medical admissions or a subset of "select" admissions that excluded possible alcohol-related admissions. Cases were selected from hospital inpatients. RESULTS: The relative risk for stroke associated with alcohol consumption greater than 300 grams per week for general control subjects was 0.73 (95% confidence interval [CI], 0.54-3.49) compared with 1.30 (95% CI, 0.42-4.05) for select control subjects. The odds ratio was further increased to 1.93 (95% CI, 0.87-4.28) using data from the community-based survey. None of these estimates were statistically significant. CONCLUSIONS: These results illustrate how the risk associated with alcohol consumption varies depending on the choice of control groups and may explain the contradictory results from previous case-control studies. Because of different biases associated with control selection, we believe that the results of this study are consistent with those of other studies that demonstrate a modest increased risk for stroke associated with alcohol consumption.
In a population sample of 'healthy' males (N = 136; age 39-41) the classifications on the Jenkins Activity Survey (JAS) for assessing the Type A/B coronary-prone behavior pattern, and on the Maastricht Questionnaire (MQ), measuring emotional drain and subsequent depression, were investigated in relation to retrospective reporting of life changes on a newly developed Middle Adulthood Life Changes Questionnaire (MALC). In ANOVA, Type A subjects (N = 70) did report significantly more life changes in their work environment and family situation over the last two years than their Type B counterparts (N = 66). For subjects reporting clearcut manifestations of vital exhaustion and depression (N = 32) the same statistical associations do hold. Also, these latter subjects did evaluate their life changes as significantly 'more distressing' or as 'requiring more adjustment'. A group of male myocardial infarction (MI) patients (N = 35; average age 52) was compared with this control group on the MQ and the MALC. The MI-group showed a significantly lower average MQ-score than the section of the control group with clearcut manifestations of emotional drain and depression. Mean 'adjustment' scores, however, were significantly higher in the MI-group. In the discussion, the requirements for a dynamic life-span developmental model for explaining the assumedly different life-courses of MI-cases and controls are enunciated.
The seven resonances observed in the histidine region of the proton magnetic resonance (pmr) spectrum of human carbonic anhydrase B and reported in the preceding paper are studied in the presence of sulfonamide, azide, cyanide, and chloride inhibitors and in metal-free, cadmium substituted, cobalt substituted, and carboxymethylated forms of the enzyme. Results indicate that the two resonances that move-downfield with increasing pH and the two that do not move with pH reflect residues located at the active site. The first two resonances are assigned to the same titratable histidine whose pK value of 8.24 corresponds to that of the group controlling catalytic activity. Addition of anions or sulfonamides, removal of zinc, or substitution of cadmium for zinc at the active site, procedures known to abolish enzymatic activity, prevent titration of this residue. Partial inhibition of carbonic anhydrase by chloride slectively increases the pK value of the group controlling catalytic activity and of the histidine with pK equals 8.24. Experiments with metal-free and cadmium carbonic anhydrases and comparisons with model systems suggest that this histidine is bound to the metal ion at high pH; at low pH this complex appears to dissociate as protons compete with the metal for the imidazole group. It is proposed that ionization of the group controlling catalytic activity represents loss of the pyrrole proton of this neutral ligand when it binds to Zn(II), forming an imidazolate anion and juxtaposing a strong base and a powerful Lewis acid at the active site. When bound to zinc as an anion, this histidine can act as a general base catalyst in the hydration of carbon dioxide and be replaced as a metal ligand by an oxygen of the substrate in the course of the reaction. The histidine-metal complex is thought to exist in a strained configuration in the active enzyme so that its imidazole-metal bond is readily broken on addition of substrates or inhibitors. This model is consistent with the available data on the enzyme and is discussed in relation to alternative proposals.
The author suggests a method of calculation of mathematically unbiased difference between the means of combined experimental and control groups and their calculated statistica-significance. Non-uniformity in the results of measurements between individual experiments is admissible. The coefficients adjusting the number of observations in the experimental and control groups to each experiment separately were found by minimizing the square of the mean error of the mentioned difference. Experimental results were united after the correction by means of the coefficients found.
Although the use of arteriography to define coronary artery disease is considered the optimal method for determining associations of risk factors with atherosclerosis, the strengths of associations found have varied greatly between arteriographic studies. To assess whether such associations are affected by changes in the arteriographic definition of absence of disease, the authors evaluated one sample of patients undergoing coronary arteriography. The prevalence of specific risk factors by the extent of atherosclerosis (0-24, 25-49, and greater than or equal to 50% maximal stenosis) was determined, as were their associations with coronary artery disease (greater than or equal to 50% stenosis), using persons with 0-24 or 0-49% maximal stenosis, separately, as control groups. Among both males and females, analysis showed increased prevalence of risk factors with increasing atherosclerosis, with greater similarity of those who had moderate atherosclerosis to the cases than to those who had minimal atherosclerosis. The strength of association of arteriographically defined coronary disease with age, hypertension, diabetes, low and high density lipoprotein cholesterol, smoking, and family history generally varied inversely with the extent of atherosclerosis permitted within the control group. These findings indicate that epidemiologic understanding of associations of risk factors with atherosclerosis may be weakened by including persons with moderate, subclinical atherosclerosis within the control group.
PURPOSE: To evaluate the uveal and capsular biocompatibility of hydrophilic acrylic, hydrophobic acrylic, and silicone intraocular lenses (IOLs) in eyes with uveitis. SETTING: Department of Ophthalmology, University of Vienna, Vienna, Austria. METHODS: This prospective study comprised 72 eyes with uveitis and 68 control eyes having phacoemulsification and IOL implantation by 1 surgeon. Patients received 1 of the following IOLs: foldable hydrophilic acrylic (Hydroview, Bausch & Lomb), hydrophobic acrylic (AcrySof, Alcon), or silicone (CeeOn 911, Pharmacia). Postoperative evaluations were at 1, 3, and 7 days and 1, 3, and 6 months. Cell reaction was evaluated by specular microscopy of the anterior IOL surface and the anterior and posterior capsule reaction, by biomicroscopy. RESULTS: Small round cell deposition was observed on all IOLs in the immediate postoperative period, especially in eyes with uveitis. This reaction decreased 3 to 6 months after surgery. Although the CeeOn 911 had a higher mean grade of small cells, there was no statistical difference between the 3 IOL types after 6 months in the uveitis and control groups. Foreign-body giant cells (FBGCs) increased after 1 week to 1 month. The AcrySof IOLs had the highest number of FBGCs; after 6 months, there was a statistically significant difference between the AcrySof and Hydroview uveitis groups (P =.036) and the AcrySof and CeeOn 911 uveitis groups (P =.003) but there was no difference among the 3 IOL types in the control group. Lens epithelial cell outgrowth persisted on the Hydroview IOLs in control eyes and regressed on all 3 IOL types in uveitic eyes and on the AcrySof and CeeOn 911 IOLs in control eyes (P =.0001). Anterior capsule opacification (ACO) was more severe on all IOL types in uveitic eyes and on the CeeOn 911 IOL in control eyes. Posterior capsule opacification (PCO) was more severe in uveitic eyes. The Hydroview group had more severe PCO than the AcrySof and the CeeOn 911 groups in uveitis and control eyes. Six months postoperatively, the difference was significant (P =.0001). There was no significant difference between the AcrySof and CeeOn 911 IOLs. CONCLUSIONS: Intraocular lens biocompatibility is inversely related to inflammation. Hydrophilic acrylic material had good uveal but worse capsular biocompatibility. Hydrophobic acrylic material had lower uveal but better capsular biocompatibility. Silicone showed a higher small cell count (mild) and more severe ACO but achieved PCO results comparable to FBGC results and better than those with the AcrySof lens 6 months after surgery. Despite the differences in IOL biocompatibility, all patients benefited from the surgery.
At the clinical-research interface, controls are a significant issue in group therapy evaluation. The authors describe and analyze their unique experience with placebo effect control groups conducted prior to brief, group psychotherapy for married couples. Procedures are outlined and participant reactions noted. Solicited ratings and spontaneous comments provide assessment data. The evidence suggests the feasibility of placebo effect control groups in the context studied. Proposed methodological refinements and clinical implications may be useful for future research efforts.
OBJECTIVE: The aim of this study was to compare tooth size measurements between patients with supernumerary teeth and a control group. METHOD: The supernumerary group consisted of 56 subjects (21 females and 35 males) and the control group of 40 subjects (20 females and 20 males). All available permanent teeth on the dental casts were imaged and measured from both buccal and occlusal views using an image analysis system. Mesio-distal, bucco-lingual or occluso-gingival dimensions, area and perimeter were measured from each view. RESULTS: Supernumerary tooth patients tended to have larger tooth size measurements for almost all variables than controls. Significant differences (p<0.05) were found for the mesio-distal dimension of the upper and lower incisors and the bucco-lingual dimensions of the lower first premolars. CONCLUSIONS: The results are compatible with supernumerary teeth being a complex dental anomaly with a multifactorial aetiology in which both genetic and environmental factors are important. There is some evidence of a local effect with greater differences in tooth dimension adjacent to the site of the supernumeraries.
CONTEXT: It has been suggested that the need for concurrent placebo control groups in new schizophrenia studies might be minimized by making comparisons with external placebo. This strategy requires an assumption of constancy, that the novel medication will perform the same way in a study with only active controls as it would have in a placebo-controlled trial. OBJECTIVE: To test this constancy assumption in active- and low dose-controlled trials vs placebo-controlled trials of atypical antipsychotic medications. DATA SOURCES: A comprehensive search of bibliographic databases, conference proceedings, and Food and Drug Administration databases through November 24, 2003. STUDY SELECTION: English-language, randomized, double-blind clinical trials of newer atypical antipsychotic medications in otherwise unselected acutely ill adults with schizophrenia or schizoaffective disorder that reported baseline and intent-to-treat end point change values for the Brief Psychiatric Rating Scale. DATA EXTRACTION: Study number, sample size, reported dosage for each arm, trial duration, percentage of men, average age, trial arm treatment completion rate, baseline and within-arm end point change in the Brief Psychiatric Rating Scale, method of scoring the Brief Psychiatric Rating Scale, and date of publication were extracted from each study independently by 2 of us (S.W.W. and C.B.B.) each. DATA SYNTHESIS: There were 32 studies comprising 66 risperidone, olanzapine, quetiapine, and ziprasidone arms including 7264 patients. Random-effects analysis revealed that in atypical antipsychotic medication arms, the degree of improvement was nearly double in active-controlled trials than that seen with the same drugs and dosages in placebo-controlled studies. An effect of design was also observed in low dose-controlled studies vs placebo-controlled studies in ineffective and intermediate antipsychotic medication dose ranges. CONCLUSIONS: The observed control group bias indicates that the constancy assumption does not hold in recent antipsychotic medication trials. These results suggest that caution is indicated when considering active- or low dose-controlled studies requiring comparisons with external placebo as alternatives to placebo-controlled trials for establishing efficacy of new medications for schizophrenia.
Five experiments used rats to examine the role of noxious stimulation in the development of contextually controlled morphine hypoalgesic tolerance and in the mediation of this tolerance by an associated hyperalgesic response. There was evidence for contextually controlled tolerance to morphine's hypoalgesic effects and an associated hyperalgesic response in rats injected with morphine and trained with noxious stimulation, but not in rats repeatedly exposed to morphine in the absence of that stimulation (Experiments 1 and 5). Latent inhibition (Experiment 2) and extinction (Experiment 3) of tolerance also depended upon pairing drug-related cues with noxious stimulation. The level of sensitivity-reactivity to noxious stimulation in morphine-tolerant rats tested with the drug was related to the intensity of the noxious stimulation that had been paired with the test context (Experiment 4). The results were interpreted to mean that some of the evidence for a Pavlovian involvement in tolerance development can be explained in terms of morphine's interference with the acquisition, but not with the expression of the hypoalgesic response otherwise acquired by cues paired with noxious stimulation.
PURPOSE: To evaluate the uveal and capsular biocompatibility of hydrophilic acrylic (Hydroview) and hydrophobic acrylic (AcrySof) intraocular lenses (IOLs) after phacoemulsification in eyes with pseudoexfoliation syndrome (PEX) or uveitis and compare the results with those in a control group. SETTING: Department of Ophthalmology, University of Vienna, Vienna, Austria. METHODS: This prospective nonrandomized comparative trial comprised 143 eyes recruited consecutively. Of these, 49 eyes had PEX, 43 had uveitis, and 51 served as controls. A standardized surgical protocol was used. Cell reaction, anterior (ACO) and posterior (PCO) capsule opacification, and flare were evaluated 1 year after cataract surgery. RESULTS: Regarding uveal biocompatibility, the number of foreign-body giant cells (FBGCs) increased in proportion to associated ocular pathologies in both IOL groups. The difference between the Hydroview control and Hydroview uveitis groups was statistically significant. The number of FBGCs was greater on AcrySof IOLs than on Hydroview IOLs in all 3 groups. The difference in FBGCs between the 2 IOL types was statistically significant in the control and PEX groups. Regarding capsular biocompatibility, lens epithelial cell (LEC) outgrowth was inversely correlated with intraocular inflammation. Outgrowth was statistically significantly higher with Hydroview IOLs, occurring in 85% in the control group, 45% in the PEX group, and 28% in the uveitis group (P <.0001). With AcrySof lenses, the percentages were 0%, 8%, and 4%, respectively. The PEX and uveitis groups were more likely to develop ACO than the control group (P <.012). There was no statistically significant difference in ACO between the 2 IOL types in the 3 patient groups. The PCO was statistically significantly greater in the uveitis group than in the control group (P <.026) and statistically significantly more dense on Hydroview than on AcrySof IOLs in all 3 patient groups (P <.002). Flare was statistically significantly higher in the uveitis group than in the PEX and control groups with both IOL types (P <.012). There was no statistically significant difference in flare between the 2 IOL types. CONCLUSIONS: Uveal and capsular biocompatibility depends on the intensity of ocular inflammation. The greater the inflammation, the less the biocompatibility of hydrophilic and hydrophobic acrylic materials. AcrySof stimulated more FBGCs. The Hydroview material had better uveal but poorer capsular biocompatibility than AcrySof. The sharp optic edge effect of the AcrySof IOL and the advantages of the Hydroview lens in normal eyes are less apparent in compromised eyes.
STUDY DESIGN: This study is a follow-up investigation for a consecutive series of patients with adolescent idiopathic scoliosis treated between 1968 and 1977. In this series, 156 patients underwent surgery with distraction and fusion using Harrington rods, and 127 were treated with brace. OBJECTIVES: To determine the long-term outcome in terms of radiologic findings and curve progression at least 20 years after completion of the treatment. SUMMARY OF BACKGROUND DATA: Radiologic appearance is important in comparing the outcome of different treatment options and in evaluating clinical results. Earlier studies have shown a slight increase of the Cobb angle in brace-treated patients with time, but not in fused patients. METHODS: Of 283 patients, 252 attended a clinical and radiologic follow-up assessment by an unbiased observer (91% of the surgically treated and 87% of the brace-treated patients). This evaluation included chart reviews, validated questionnaires, clinical examination, and full-length standing frontal and lateral roentgenographs. Curve size was measured by the Cobb method on anteroposterior roentgenograms as well as by sagittal contour and balance on lateral films. The occurrence of any degenerative changes or other complications was noted. An age- and gender-matched control group of 100 individuals was randomly selected and subjected to the same examinations. RESULTS: The mean follow-up times were 23 years for surgically treated group and 22 years for brace-treated group. The deterioration of the curves was 3.5 degrees for all the surgically treated curves and 7.9 degrees for all the brace-treated curves (P < 0.001). Five patients, all brace-treated, had a curve increase of 20 degrees or more. The overall complication rate after surgery was low: Pseudarthrosis occurred in three patients, and flat back syndrome developed in four patients. Eight of the patients treated with fusion (5.1%) had undergone some additional curve-related surgical procedure. The lumbar lordosis was less in the surgically treated than in the brace-treated patients or the control group (mean, 33 degrees vs 45 degrees and 44 degrees, respectively). Both surgically treated and brace-treated patients had more degenerative disc changes than the control participants (P < 0.001), but no significant differences were found between the scoliosis groups. No statistically significant difference in terms of radiographically detectable degenerative changes in the unfused lumbar discs was found between patients fused below L3 or those fused to L3 and above (P = 0.22). A study on intra- and interobserver measurements of kyphosis, lordosis, and sagittal vertical axis on two films for each patient demonstrated that the repeatability of measuring sagittal plumbline on two different lateral radiographs, with patients moving between radiograms, was unreliable for comparison. CONCLUSIONS: Although more than 20 years had passed since completion of the treatment, most of the curves did not increase. The surgical complication rate was low. Degenerative disc changes were more common in both patient groups than in the control group.
The comparative auditory performance of 61 industrially exposed male textile workers (noise level, 90 dBA - 115 DBA) and 90 age matched control subgroup was determined by means of a manual Diacoustic As-60 audiometer. The audiograms of both the exposed and control subgroups were convex upwards, indicating that the hearing sensitivity of the Nigerian, black subjects increased with frequency, a finding that is in contrast with that reported elsewhere for white subjects. The impact of ageing on the hearing of both the exposed and control groups was minimal and not statistically significant, supporting an earlier study that found no age related hearing loss among South Sudanese blacks. The impact of noise on the hearing of the subjects was, however, very marked. In each age group and at each frequency, the hearing thresholds of the exposed subjects were significantly higher (0.01 greater than p less than 0.005) than those of the control group. After seven years of continuous employment, the rate of hearing loss attributable to noise, among the exposed group, increased from 2.17 dB to 11.67 dB per year of employment compared to an increase of - 0.64 dB to 1.82 dB in age induced loss per year of age difference in the same group. It seemed the exposed subjects experienced a seven year hearing threshold of 30 dB irrespective of statistically significant differences in age (p less than 0.005) and duration of employment (p less than 0.01) of the groups covered by this period. After this "latency period" the hearing loss increased rapidly.
We aimed to illustrate the importance of control-group selection on the results of risk factor analysis for (1) imipenem-resistant Pseudomonas aeruginosa, (2) vancomycin-resistant enterococci (VRE), and (3) ampicillin-sulbactam-resistant Escherichia coli. Case patients were compared with 2 different control groups: patients with the susceptible form of the organism (type 1), and control patients among whom the case patients arose during the same period as the case patients (type 2). Comparison of case patients who had imipenem-resistant P. aeruginosa with type-1 control patients identified use of imipenem (odds ratio [OR], 27.1) and quinolones (OR, 3.25) as a risk factor for selection of antimicrobial resistance, and comparison of the same case patients with type-2 control patients identified imipenem (OR, 6.34). When case patients with VRE were compared with type-1 and with type-2 control patients, use of vancomycin was identified as a risk factor (OR, 4.38 and 2.77, respectively). Comparison of case patients who had ampicillin-sulbactam-resistant E. coli compared with type-1 control patients identified ampicillin-sulbactam (OR, 2.71) and quinolones (OR, 2.72), and comparison with type-2 control patients identified ampicillin-sulbactam (OR, 1.68). The selection of control patients from the potentially suboptimal control type 1 can falsely identify certain antibiotics and overestimate the OR of the resistance-defining antibiotic.
BACKGROUND: The follow-up of patients with an acute myocardial infarction treated with fibrinolysis and that of patients treated with conventional therapy was analyzed. PATIENTS AND METHODS: The study cohort included: 1) 214 patients with a first acute infarction of < or = 4 hours and with < or = 70 years of age who participated in a randomized study comparing the effects of streptokinase (SK, n: 110) vs conventional treatment (control, n: 104), and 2) a total of 361 patients with a myocardial infarction of < or = 6 hours and < or = 75 years old treated with fibrinolytic agents. RESULTS: In-hospital mortality in the randomized study was 11% for the control group and 7% for the SK group, and 8.8% for the rest of patients treated with fibrinolysis. Mortality during follow-up in the randomized study (7.0 +/- 1.5 years) was 10.7% for the SK group and 19.3% for the control group. Ejection fraction was significantly lower in non survivors than in survivors (36.7% vs 50.8%, (p < 0.0001) and among patients with an ejection fraction < 50%, follow-up mortality was significantly lower in those with a complete recanalization (TIMI 3) than in those with an absent or incomplete recanalization (TIMI 0-2) (98% vs 22%). Follow-up mortality for the rest of patients treated with fibrinolysis (2.6 +/- 1.6 years) was 9%. CONCLUSIONS: 1) The reduction of in-hospital mortality by fibrinolysis appears to increase in the long-term follow-up, and 2) the long-term survival seems to be related not only to the left ventricular function but also to the extent of angiographic recanalization.