Improving population health or the population itself? Health technology assessment and our genetic future

The province of British Columbia (BC), Canada is developing its first population-wide prenatal genetic screening program, known as triple-marker screening (TMS). TMS, initiated with a simple blood test, is most commonly used to screen for fetuses with the chromosomal abnormality known as Down syndrome or neural tube disorders. Women testing TMS-positive are offered diagnostic amniocentesis and, if the diagnosis is confirmed, selective second-trimester abortion. The project described in this study was initiated to address the broad range of issues arising from this testing technology and provides an example of the new type of health technology assessment (HTA) contribution emerging (and likely to become increasing necessary) in health policy development. With the advent of prenatal genetic screening programs, would-be parents gain the promise of identifying target conditions and, hence, the option of selective abortion of affected fetuses. There is considerable awareness that these developments pose challenges in every dimension (ethical, political, economic, and clinical) of the health-care environment. In the effort to construct an appropriate prenatal screening policy, therefore, administrators have understandably sought guidance from within the field of HTA. The report authors concluded that, within the restricted path open to it, the role of government is relatively clear. It has the responsibility to maintain equal access to prenatal testing, as to any other health service. It should also require maintenance of medical standards and evaluation of program performance. At the same time, policy-makers need actively to support those individuals born with disabilities and their families.

The need to redefine non-cystic fibrosis bronchiectasis in childhood

BACKGROUND

Non-cystic fibrosis (CF) bronchiectasis has previously been reported to be rare and progressive in children living in western societies.

METHOD

A clinical and radiological review was undertaken of 93 children with non-CF bronchiectasis defined by high resolution computed tomographic (HRCT) scanning presenting to a tertiary paediatric respiratory centre since 1996.

RESULTS

Cases constituted 9.6% of all new referrals. Male to female ratio was 2:1. Median age at symptom onset was 1.1 years (range 0-16) and of HRCT diagnosis was 7.2 years (1.6-18.8). The most common referral diagnosis of asthma was refuted in 39 of 45 cases. Associations were previous pneumonic illness (30%), immunocompromise (21%), obliterative bronchiolitis (9%), congenital lung abnormality (5%), chronic aspiration (3%), eosinophilic oesophagitis (2%), familial syndrome (2%), primary ciliary dyskinesia (1%), and right middle lobe syndrome (1%). 8% had two associated diagnoses and 18% were idiopathic. There was agreement between the chest radiograph and HRCT scan for diagnosis and lobe affected in only five cases (5%). A repeat HRCT scan in 18 cases at a minimum interval of 18 months showed total resolution of the changes in six, improvement in one, progression in five, and was unchanged in six.

CONCLUSIONS

Radiologically defined non-CF bronchiectasis in children is not uncommon. Diagnostic delay is a problem. The most common association is a previous pneumonia. Chest radiography is of little diagnostic value, but resolution is possible on HRCT scanning. Bronchiectasis is currently defined as a condition which is both permanent and progressive. This term is not necessarily appropriate for all paediatric patients for whom we suggest an alternative nomenclature.

Lercanidipine vs lacidipine in isolated systolic hypertension

This randomised, double-blind, double-dummy, parallel group, multicentre study compared the efficacy and tolerability of lercanidipine with lacidipine. Elderly patients with isolated systolic hypertension (supine blood pressure >/=160/<95 mmHg) were enrolled and underwent a placebo run-in period of 14-27 days before random allocation to lercanidipine tablets 10 mg once daily (n=111) or lacidipine tablets 2 mg once daily (n=111) for the assessment period (112-160 days). Titration to lercanidipine 20 mg once daily (two 10 mg tablets) or lacidipine 4 mg once daily (two 2 mg tablets) was allowed after 8 weeks, if required. Both treatments decreased supine and standing systolic and diastolic blood pressure between the end of the run-in period and the end of the assessment period (P<0.0001). At the end of the assessment period, the estimated mean treatment difference (95% confidence intervals) in supine systolic blood pressure was -0.81 (-4.45, 2.84) mmHg. These confidence intervals were within the limits specified for equivalence, that is, (-5, 5) mmHg. Ambulatory blood pressure monitoring showed that the antihypertensive effects of both drugs lasted for the full 24-h dosing period and followed a circadian pattern. Both treatments were well tolerated with a low incidence of adverse drug reactions and a low withdrawal rate. Significantly fewer patients withdrew from treatment with lercanidipine (P=0.015). Neither treatment had any clinically significant effect on pulse rate or cardiac conduction. In conclusion, both treatments were equally effective in controlling supine systolic blood pressure in patients with isolated systolic hypertension.

Do Thoroughbred and Standardbred horses have similar increases in pulmonary vascular pressures during exertion?

To test the hypothesis that the pulmonary vascular pressures of Thoroughbred and Standardbred horses behave similarly during exertion. Measurements were made on 5 Thoroughbred and 5 Standardbred horses on a treadmill at rest and during 3-minute exercise intervals at speeds predicted to produce 75%, 90%, and 100% maximal heart rate. Left forelimb acceleration, heart rate, esophageal pressure, and pulmonary artery pressure were measured continuously. Pulmonary capillary and wedge pressures were measured during intermittent occlusion of the pulmonary artery. Breathing rate and gait frequency were the fundamental frequencies of the esophageal pressure and limb acceleration signals respectively. The ratio of speed:gait frequency gave stride length. The effects of exertion and breed were evaluated using two-way analysis of variance. Exertion produced significant increases in pulmonary artery (P = 0.001), capillary (P = 0.002), and wedge (P = 0.005) pressures. No significant effect of breed was detected on pulmonary artery pressure, but at exertion pulmonary capillary and wedge pressures were 15% (P = 0.03) and 23% (P = 0.04) greater in Thoroughbreds, respectively. Treadmill speed was approximately 12% greater (P = 0.04), stride length was approximately 25% greater (P = 0.0003), gait frequency was approximately 10% less (P = 0.006), breathing rate was approximately 10% less (P = 0.001), and heart rate was approximately 6% less (P = 0.06) for Thoroughbreds. There was no effect of breed on inspiratory or expiratory esophageal pressure although mean esophageal pressure was approximately 2 mmHg greater (P = 0.03) in exercising Standardbreds. In conclusion, pulmonary capillary and wedge pressures are greater in Thoroughbreds than in Standardbreds at similar fractions of maximal heart rate. This is compatible with the higher incidence of exercise-induced pulmonary hemorrhage observed in Thoroughbreds.

Hepatic and intestinal cytochrome P450 and conjugase activities in rats treated with black tea theafulvins and theaflavins

Theaflavins and theafulvins, a fraction of thearubigins, were isolated from aqueous infusions of black tea, and their effects on the hepatic and intestinal cytochrome P450 system, and on the glutathione S-transferase, epoxide hydrolase, glucuronosyl transferase and sulphotransferase enzyme systems were investigated in rats following oral intake for four weeks. Neither theafulvins nor theaflavins influenced cytochrome P450 activity in the liver as exemplified by the O-dealkylations of methoxy-, ethoxy- and pentoxyresorufin, the hydroxylations of lauric acid and p-nitrophenol, and the N-demethylation of erythromycin; similarly, hepatic xenobiotic conjugation systems were unaffected. In the intestine, both polyphenolic fractions markedly suppressed the O-deethylation of ethoxyresorufin and this was accompanied by a decrease in the CYP1A1 apoprotein levels. Probing intestinal microsomes with antibodies to CYP2E1 revealed the presence of a single band in the cytochrome P450 region whose intensity was lower in the polyphenol-treated animals. Immunoblot analysis utilising antibodies to CYP3A showed that the treatment with theafulvins and theaflavins reduced the apoprotein levels. A single band in the cytochrome P450 region was evident when the intestinal microsomes were probed with antibodies to CYP4A1 but the level of expression was not affected by the treatment with the black tea polyphenols. Finally, treatment of the rats with theaflavins had no effect on any of the intestinal conjugating enzymes studied, but treatment with theafulvins led to inhibition of glucuronosyl transferase activity.

Clinical and electrophysiological differences between patients with arrhythmogenic right ventricular dysplasia and right ventricular outflow tract tachycardia

AIMS

Radiofrequency catheter ablation is considered first line treatment for symptomatic patients with right ventricular outflow tract tachycardia (RVOT). The role of ablation in arrhythmogenic right ventricular dysplasia (ARVD) is more limited. As such, differentiating between the two conditions is essential.

METHODS AND RESULTS

This study compared non-invasive findings, magnetic resonance images (MRI), invasive electrophysiological characteristics, results of ablation and long-term outcome in 50 consecutive patients with RVOT (33) or ARVD (17). Structural abnormalities were uniform in the ARVD group; in addition 18 (54%) of the RVOT tachycardia group had MRI abnormalities. At electrophysiological study the tachycardia in the ARVD group displayed features of re-entry in over 80%, but behaved with a triggered automatic basis in 97% with RVOT. Ablation was complete or partial success in 12 (71%) patients with ARVD and ventricular tachycardia (VT) recurred in eight (48%). In the RVOT patients, ablation was a complete success in 97% with recurrent VT in 6%. Long-term success in the RVOT patients was 95% in both patients with and without MRI abnormalities.

CONCLUSIONS

Electrophysiological characterization can differentiate ARVD from RVOT. The finding of abnormalities on MRI does not have any bearing on arrhythmia mechanism, acute or long-term success of RFA.

The effect of ReTain plant growth regulator [aminoethoxyvinylglycine (AVG)] on the postharvest storage life of 'Tegan Blue' plums

ReTain plant growth regulator is a commercial formulation of aminoethoxyvinylglycine (AVG). This compound is known to competitively inhibit the activity of the enzyme ACC (1-aminocyclopropanecarboxylate) synthase which is the rate limiting enzyme in the ethylene biosynthesis pathway. By inhibiting the activity of ACC synthase, ethylene-mediated ripening processes can be delayed.'Tegan Blue' plums have low ethylene production, which indicates that it is a suppressed climacteric variety. There was a significant difference between the ReTain treated and untreated fruit for the second harvest, this difference was greater later in storage than early in storage. The results indicate that there is a postharvest benefit achieved after applying AVG to 'Tegan Blue' plums. The main advantage is in the maintenance of firmness for late-harvested fruit. Other benefits are the suppression of ethylene production and the development of a more intense colour.

A randomized controlled trial to investigate brackets bonded with a hydrophilic primer

OBJECTIVE

To compare the clinical failure rates of brackets bonded using a prototype hydrophilic primer, designed to be insensitive to moisture, with brackets bonded with a conventional primer.

DESIGN

Single centre randomised controlled clinical study. Thirty-three patients were bonded using a split mouth technique: randomly allocating the hydrophilic primer to one side of the mouth and a conventional primer to the other.

SETTING

Hospital orthodontic department, Bradford, UK.

SUBJECTS

Orthodontic patients requiring fixed appliances.

MAIN OUTCOME MEASURES

The site and time to bond failure was recorded for each bracket that failed over 6 months.

RESULTS

Using survival analysis, there was an increased risk of bracket failure when bonded with the hydrophilic primer compared with the conventional primer (hazard ratio = 2.2, 95% confidence interval: 1.1 to 4.5, P = 0.01).

CONCLUSIONS

This hydrophilic primer cannot be recommended for routine clinical use.

Behçet's disease complicated by pylephlebitis and hepatic abscesses

A 22 year old man presented with fever, abdominal pain, weight loss and diarrhea. Past medical history revealed recurrent aseptic meningitis, uveitis, and erythema nodosum. Further inquiry unveiled a prominent history of oral aphthous ulcers; all features of Behçet's disease. Imaging revealed mesenteric arteritis and pylephlebitis, septic thrombophlebitis of the portal vein, a previously unrecognized complication of Behçet's disease, with multiple intrahepatic abscesses. Portal venography demonstrated an extensively diseased, expanded, and obstructed portal venous system. Blood cultures and portal vein aspirate yielded polymicrobial flora. Percutaneous intraportal thrombolytic therapy and mechanical thrombectomy were attempted to restore flow to the portal venous system. This distinctly rare manifestation of Behçet's Disease, pylephlebitis, may result from ischemic injury and structural compromise of the bowel mucosa, resulting from underlying vasculitis.

Fluoride-releasing elastomeric modules reduce decalcification: a randomized controlled trial

OBJECTIVE

To determine whether fluoride releasing elastomeric modules reduced the incidence of decalcification around orthodontic brackets during a complete course of orthodontic treatment.

DESIGN

A randomised controlled, split mouth design.

SETTING

The study was carried out in the orthodontic department of Newcastle-upon-Tyne Dental Hospital, UK.

SUBJECT AND METHODS

21 consecutive patients (126 teeth) undergoing fixed appliance therapy were studied. A split mouth technique was adopted to examine the upper labial segment, where one side (left or right) was randomly assigned to the experimental group, and the opposite side served as a control throughout their course of orthodontic treatment.

INTERVENTIONS

The control teeth were ligated to the archwire using conventional modules. The experimental teeth were ligated to the archwire using Fluoride releasing elastomeric modules.

OUTCOME MEASURES

Standardised photographs were taken of the upper labial segment before and after completion of orthodontic treatment, and the degree of decalcification assessed in each tooth quadrant, using a modification of the Enamel Defect Score.

RESULTS

Decalcification was found to occur in both treatment groups, though to a significantly greater degree on the control side (p = 0.002). The fluoride module side showed significantly fewer serious decalcified lesions than the control (p = 0.013). No patients withdrew from the study.

CONCLUSIONS

It would appear that the use of fluoride releasing elastomeric modules reduces the degree of decalcification experienced during orthodontic treatment.

Characterization of the active sites in decay-accelerating factor

Decay-accelerating factor (DAF) is a complement regulator that dissociates autologous C3 convertases, which assemble on self cell surfaces. Its activity resides in the last three of its four complement control protein repeats (CCP2-4). Previous modeling on the nuclear magnetic resonance structure of CCP15-16 in the serum C3 convertase regulator factor H proposed a positively charged surface area on CCP2 extending into CCP3, and hydrophobic moieties between CCPs 2 and 3 as being primary convertase-interactive sites. To map the residues providing for the activity of DAF, we analyzed the functions of 31 primarily alanine substitution mutants based in part on this model. Replacing R69, R96, R100, and K127 in the positively charged CCP2-3 groove or hydrophobic F148 and L171 in CCP3 markedly impaired the function of DAF in both activation pathways. Significantly, mutations of K126 and F169 and of R206 and R212 in downstream CCP4 selectively reduced alternative pathway activity without affecting classical pathway activity. Rhesus macaque DAF has all the above human critical residues except for F169, which is an L, and its CCPs exhibited full activity against the human classical pathway C3 convertase. The recombinants whose function was preferentially impaired against the alternative pathway C3bBb compared with the classical pathway C4b2a were tested in classical pathway C5 convertase (C4b2a3b) assays. The effects on C4b2a and C4b2a3b were comparable, indicating that DAF functions similarly on the two enzymes. When CCP2-3 of DAF were oriented according to the crystal structure of CCP1-2 of membrane cofactor protein, the essential residues formed a contiguous region, suggesting a similar spatial relationship.

MRI changes in multiple sclerosis following treatment with lofepramine and L-phenylalanine

As part of a large, randomized placebo-controlled trial of inpatients with multiple sclerosis (MS), a subsample of 15 underwent cerebral MRI at baseline and 6-months (eight on lofepramine and l-phenylalanine; seven on placebo). Unlike the placebo group, the active group showed a significant reduction in lesion number visible on T1-weighted scans (p < 0.05). The lateral ventricular volume increased, on average, by 1020 mm3 in the untreated group and 600 mm3 in the treated group. In the treated patients the ventricular size change correlated with both change in Gulick MS-related symptoms scale scores (rs = 0.71, p = 0.07) and Gulick MS-related activities of daily living scale scores (rs = -0.83, p = 0.02). It is concluded that treatment with lofepramine and l-phenylalanine is associated with significant MRI changes.

Development and application of a quantitative, specific assay for Cryptosporidium parvum oocyst detection in high-turbidity environmental water samples

Chlorine-resistant Cryptosporidium parvum oocysts in drinking water play an important role in the epidemiology of cryptosporidiosis. Current methods of detecting these organisms in water are insensitive, labor-intensive, highly subjective, and severely limited by sample turbidity. We describe here an alternative technique utilizing electrochemiluminescence (ECL) technology for detecting C. parvum oocysts in environmental water samples. This method is quantitative, reproducible, and requires only minimal sample processing. Currently, the ECL assay can detect as few as one oocyst in one milliliter of concentrated test sample with sample turbidity of up to 10,000 nephelometric turbidity units. Water and sewer samples collected during a cryptosporidiosis outbreak were tested by ECL assay. Cryptosporidium parvum oocysts were found in the source water at the time of outbreak, and a sharply decreasing level of oocysts in sewer samples was observed over a three-month period following the outbreak.

Early and periodic screening, diagnosis, and treatment examination completion rates for Oklahoma Medicaid managed care: 1995-1998

Although quality medical care is a goal of all health care providers, finding a means by which to take that idea from the abstract to the measurable is often an arduous task. The Oklahoma Health Care Authority and the Oklahoma Foundation for Medical Quality confronted that challenge when examining the state of Oklahoma's Early and Periodic Screening, Diagnosis, and Treatment (EPSDT) examination completion rates. Focused on measuring processes of care, the Oklahoma Health Care Authority (OHCA) and the Oklahoma Foundation for Medical Quality (OFMQ) used chart abstraction to track EPSDT examination rates for SoonerCare Plus Medicaid managed care recipients from 1995 through 1998. During the abstractions, an examination was interpreted as an EPSDT screen if a comprehensive health and development history plus a comprehensive unclothed physical examination were recorded. Examination rates have improved from 1995 when there was a documented 17.6% completion rate. The 1998 documented rate of completion was 60.0%. Trend analysis shows significant improvement over the four-year period. The results also suggest the necessity for continued improvement in the provision of documented EPSDT examinations to individuals in Medicaid managed care plans in Oklahoma.

Elevated blood pressure predicts the risk of acute rejection in renal allograft recipients

BACKGROUND

Acute rejection (AR) is a strong predictor of renal allograft survival. Recent advances in immunosuppression have reduced considerably the incidence of AR. Still, approximately 25% of patients have AR early post-transplant, and the factors that predispose to AR have not been fully clarified.

METHODS

The study includes 1641 adults, recipients of first cadaveric (CAD, N = 1195) or living related renal grafts (LRD, N = 446), transplanted in one institution. The variables associated with the occurrence of AR during the first year post-transplant were identified.

RESULTS

By univariate analyses, AR was associated with the following variables: younger (P < 0.001); heavier (P = 0.003); and African American recipients (P = 0.002); CAD transplants (P = 0.001); higher number of HLA mismatches (P = 0.001); delayed graft function (DGF, P = 0.001); higher levels of serum creatinine post-transplant (P = 0.003); and higher levels of systolic and/or diastolic blood pressure (BP) post-transplant (P < 0.001). Higher BP levels were also associated with earlier AR episodes (P < 0.0001). By multivariable analysis AR was significantly associated with recipient age, number of HLA mismatches, DGF, pre-PRA and systolic BP. Analysis of BP measured weekly post-transplant indicated that elevated BP levels, even three weeks prior to the AR episode, were significantly associated with AR. For every level of BP, the use of BP medications was associated with a lower incidence of AR (P < 0.0001). Furthermore, the use of calcium channel blockers was also associated with lower incidence of AR (P = 0.001). Of note, 81% of recipients whose BP increased after the transplant had AR. In contrast, 22% of patients whose BP declined post-transplant had AR.

CONCLUSIONS

Elevated BP levels post-transplant identify patients at high risk of AR independently of graft function. Treatment of BP and reduction of BP levels appears to be associated with a decreased risk of AR. We hypothesize that high BP may be an indicator of a particular type of allograft damage, perhaps ischemic, that may predispose to AR.

Preoperative vancomycin prophylaxis for newly placed peritoneal dialysis catheters prevents postoperative peritonitis

The role of vancomycin and other antibiotics in treatment of acute peritonitis in peritoneal dialysis patients is well established. However, the role of preoperative vancomycin or cephalosporins in preventing early infection in newly placed peritoneal dialysis catheters remains controversial. We performed a prospective randomized study to examine the role of vancomycin or cefazolin prophylaxis in decreasing the incidence of postoperative peritonitis. Over 8-year period, 265 patients undergoing 305 permanent peritoneal catheter placement procedures were randomized into three groups. Group I (103 procedures) received a single intravenous (i.v.) dose of 1000 mg vancomycin 12 hours before the peritoneal catheter placement procedure. Group II (102 procedures) received a single i.v. dose of 1000 mg of Ancef (cefazolin) 3 hours before the procedure. Group III (100 procedures) received no antibiotics preoperatively for a least one week before the procedure. Patients were monitored for peritonitis during the following 14 days. Peritonitis developed in 1 patient (1%) in Group I (vancomycin group) compared to 12 patients (12%) in Group III (control group), p = 0.002, and in 9 patients (9%) in Group II (cefazolin group) compared to Group III, p = 0.68. We conclude that the use of preoperative single-dose i.v. vancomycin prophylaxis for permanent peritoneal dialysis catheter placement reduces the risk of postoperative peritonitis. Cefazolin did not achieve a statistically significant difference from the control group and may not provide adequate prophylaxis.

Acquired activated protein C resistance is associated with lupus anticoagulants and thrombotic events in pediatric patients with systemic lupus erythematosus

Acquired activated protein C resistance (APCR) has been hypothesized as a possible mechanism by which antiphospholipid antibodies (APLAs) cause thrombotic events (TEs). However, available evidence for an association of acquired APCR with APLAs is limited. More importantly, an association of acquired APCR with TEs has not been demonstrated. The objective of the study was to determine, in pediatric patients with systemic lupus erythematosus (SLE), whether (1) acquired APCR is associated with the presence of APLAs, (2) APCR is associated with TEs, and (3) there is an interaction between APCR and APLAs in association with TEs. A cross-sectional cohort study of 59 consecutive, nonselected children with SLE was conducted. Primary clinical outcomes were symptomatic TEs, confirmed by objective radiographic tests. Laboratory testing included lupus anticoagulants (LAs), anticardiolipin antibodies (ACLAs), APC ratio, protein S, protein C, and factor V Leiden. The results revealed that TEs occurred in 10 (17%) of 59 patients. Acquired APCR was present in 18 (31%) of 58 patients. Acquired APCR was significantly associated with the presence of LAs but not ACLAs. Acquired APCR was also significantly associated with TEs. There was significant interaction between APCR and LAs in the association with TEs. Presence of both APCR and LAs was associated with the highest risk of a TE. Protein S and protein C concentrations were not associated with the presence of APLAs, APCR, or TEs. Presence of acquired APCR is a marker identifying LA-positive patients at high risk of TEs. Acquired APCR may reflect interference of LAs with the protein C pathway that may represent a mechanism of LA-associated TEs. (Blood. 2001;97:844-849)

Role of preoperative antibiotic prophylaxis in preventing postoperative peritonitis in newly placed peritoneal dialysis catheters

The role of vancomycin and other antibiotics in the treatment of acute peritonitis in peritoneal dialysis (PD) patients is well established. However, the role of preoperative vancomycin or cephalosporins in preventing early infection in newly placed PD catheters remains controversial. We performed a prospective randomized study to examine the role of vancomycin or cefazolin prophylaxis in decreasing the incidence of postoperative peritonitis. Over a 6-year period, 221 patients undergoing 254 permanent peritoneal catheter placement procedures were randomized into three groups. Group I patients (86 procedures) were administered a single intravenous (IV) dose of vancomycin, 1,000 mg, 12 hours before peritoneal catheter placement procedures, whereas group II patients (85 procedures) were administered a single IV dose of cefazolin, 1,000 mg, 3 hours before the procedure. Group III patients (83 procedures) were not administered antibiotics preoperatively for at least 1 week before the procedure. Patients were monitored for peritonitis in the following 14 days. Peritonitis developed in 1 patient (1%) in group I (vancomycin group) and 6 patients (7%) in group II (cefazolin group) compared with 10 patients (12%) in group III (control group); P = 0.02. We conclude that the use of preoperative single-dose IV vancomycin prophylaxis for permanent PD catheter placement reduces the risk for postoperative peritonitis. Single-dose vancomycin is superior to single-dose cefazolin in reducing the risk for postoperative peritonitis. Absence of prophylaxis is associated with a high risk for developing postoperative peritonitis.

A common measure of disease-gene associations for case-control and tdt studies

PURPOSE: Associations between a disease and a candidate gene can be evaluated in case-control studies, or using the transmission/disequilibrium test (TDT) in data from studies of case-parent trios. Consequently, data for a given disease-gene association are often available from both case-control and "TDT studies." The present investigation was undertaken to identify a measure of the magnitude of a disease-gene association that could be estimated using data from either type of study.METHODS: The magnitude of a disease-gene association detected using the TDT can be estimated by the frequency (T) with which heterozygous parents transmit the putative, high-risk allele to affected offspring. To derive an expression for T that could be solved using data from a case-control study, T was first rewritten as a function of the relative frequencies of the genotypes, at the candidate gene, among the affected offspring of a heterozygous parent. By application of Bayes' theorem, this equation was reduced to a form that could be solved using case-control data.RESULTS: T can be expressed as a function of the genotypic probabilities among individuals with the disease of interest and the frequency of the high-risk allele in the general population, which can be estimated from cases and controls, respectively. Hence, estimates of T can be derived from the data available in a case-control study.CONCLUSIONS: The parameter T, which provides a measure of the magnitude of a disease-gene association, can be estimated from either case-control or TDT data and, therefore, provides a means by which to compare results from these two types of studies. As in other areas of epidemiology, comparison of a quantitative measure of the magnitude of an association, as well as the direction and statistical significance of the association, should greatly aid in the interpretation of the overall body of literature on a particular disease-gene association, and may help to clarify seemingly discrepant results.

Investigation of a hydrophilic primer for orthodontic bonding: an in vitro study

A common reason for bond failure is moisture contamination. This study investigates the in vitro bond strength of brackets bonded using a new hydrophilic primer, designed to be insensitive to moisture, and compares it with a conventional primer. Using a standardized technique, the in vitro bond strength of brackets bonded with the hydrophilic primer was compared to identical brackets bonded with a conventional primer. Although designed to be moisture insensitive, the directions for use stipulate drying the teeth before bonding. Therefore, for the purposes of comparison with a conventional primer the experiment was conducted under dry conditions. The results were analysed using the Weibull distribution modelling. The median bond strength with the hydrophilic primer (6.43 MPa, 95 per cent C.I. 7.69-9.50) was significantly lower (P = 0.0001) than the conventional primer (8.71 MPa, 95 per cent C.I. 5.89-7.59). The Weibull distribution modelling showed that brackets bonded with the hydrophilic primer were 3.96 times more at risk of failure (95 per cent C.I.: 2.39-6.56; P <0.0001). The bond strength at which 5 per cent of the brackets failed was also lower for the hydrophilic primer. The bond strengths obtained with the hydrophilic primer were significantly lower than with the conventional primer. Although the median bond strength values were promising, the laboratory results for this particular hydrophilic primer were disappointing when using the Weibull analysis, where the whole distribution of bond strength is taken into account.

Consumer Assessment of Health Plans Survey (CAHPS) results for Oklahoma managed care Medicaid, 1997, 1998, and 1999

Consumer satisfaction surveys have become an important source of information for purchasers and consumers of health care and health care organizations themselves. Individuals receiving health care provide valuable information regarding access, use of services, and satisfaction with care that can be used for multiple evaluative purposes. The Oklahoma Health Care Authority has adopted the Consumer Assessment of Health Plans Survey (CAHPS) to measure patient satisfaction for the SoonerCare managed care programs. The Oklahoma Foundation for Medical Quality administered the surveys. The adult and child CAHPS core questionnaires served as the basis for the general surveys in 1997 and 1998. The CAHPS for Children with Special Needs survey results and the Pediatric Adaptation of the CAHPS Behavioral Health Survey results were administered in 1999 for baseline measures. Results indicated an overall increase in consumer satisfaction levels across the two CAHPS core questionnaires. Baseline measures for special needs populations were also established.

Cotinine levels in Southeast Asian smokers

Understanding the contribution of race to factors associated with cigarette smoking and nicotine metabolism is essential for the characterization of patterns of tobacco use, nicotine dependence and incidence of tobacco-related diseases. This paper reports an investigation of cotinine levels among Southeast Asian smokers in two separate studies. Study 1 included 327 male and female smokers who participated in community-based interviews where smoking history information was obtained and a saliva continine sample was collected. Results indicated that subjects smoked an average of 11.2 cigarettes/day, with men reporting significantly higher consumption rates as compared to women (p < 0.0001). Subjects' mean cotinine level was 65 ng/ml with an average cotinine/cigarette ratio of 8.2. In Study 2, plasma and saliva cotinine in six Southeast Asian adult smokers were measured during 2 days of smoking followed by 6 days of abstinence. On day 1, mean plasma and saliva continine levels were 268 and 235 ng/ml, respectively. After 6 days of abstinence, mean levels had dropped to 12 ng/ml for plasma and 8 ng/ml in saliva. On average, it required at least 4.7 days for saliva continine levels to reach < 14 ng/ml. Mean cotinine concentrations during smoking differed in these two separate studies. Implications of these findings are discussed and future research recommendations are presented.