Sequential Depth Stimulation Within the Psoas Offers No Benefit for Localization of the Lumbar Plexus During Lateral Lumbar Fusion Surgery.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: In this study we aim to assess the difference in triggered EMG readings throughout different depths in the psoas muscle during the lateral approach to the lumbar spine and their effect on surgeon decision making. METHODS: Three surgeons, practicing at different institutions, assessed triggered EMG readings during the trans psoas approach at the level of the disc and 5,10 and 15 millimeters into the psoas muscle with sequential dilators. Measurement of distance into the psoas muscle was done with a specially designed instrument. Results of anterior and posterior directed stimulation as well as the delta value between these were recorded and underwent statistical analysis. Patients who had partial readings were excluded from the study. RESULTS: A total of 40 levels in 35 patients were included in the study. There was no significant difference found between means of anterior or posterior threshold readings along the different distance groups. A significant difference was found (P = .024) in the mean difference between the distance groups with a decrease in the difference between anterior and posterior threshold values found as the distance from the disc space increased. None of the surgeons reported a decision to abort the fusion of a spinal level. CONCLUSIONS: In the trans-psoas approach to the lumbar spine, the assessment of the location of the femoral nerve using directional neuromonitoring when advancing in the psoas muscle shows no clear benefit as opposed to stimulating solely when adjacent to the disc space.

Exposure to ultrafine particles and cognitive decline among older people in the United States.

BACKGROUND: Some studies suggest that ambient particulate air pollution is associated with cognitive decline. However, the findings are mixed, and there is no relevant research examining the influences of ultrafine particles (UFP), which may have more toxicity than larger particles. We therefore conducted this study to investigate whether residential UFP exposure is associated with cognitive decline using data from the Alzheimer's Disease Research Centers in the United States. METHODS: This is a longitudinal study of participants who were aged 65 years and older and had normal cognitive status at baseline. Residential UFP exposure, expressed as particle number concentrations (PNC), was assessed in 2016-2017 using a nationwide land use regression model, and was assigned to each participant using their 3-digit residential ZIP codes. Cognitive functions including memory, attention, language, executive function, and global function were assessed annually using 15 neuropsychological tests from March 2015 to February 2022. Linear mixed-effects models were used to examine the associations after adjustment for covariates including baseline age, sex, APOE ε4 status, race, education, smoking status, history of diabetes, quartiles of neighborhood median household income, and interaction terms of follow-up time with each covariate. RESULTS: This study included 5646 participants (mean age 76 years, 65% female). On average, each participant had 4 annual visits. When PNC was treated as a continuous variable, there were no statistically or clinically significant changes in annual decline of each cognitive function in relation to an interquartile range elevation in PNC (4026 particles/cm3). Similarly, when PNC was treated as a categorical variable including five exposure groups, there were no linear exposure-response trends in annual decline of each cognitive function across the five exposure groups. CONCLUSIONS: This study found no meaningful associations between residential UFP exposure and cognitive decline in global and domain-specific functions. There is a need for further research that assigns UFP exposure at a finer geographic scale.

Association of Opioid and Stimulant Use Disorder Diagnoses With Fatal and Nonfatal Overdose Among People With a History of Incarceration.

Importance: Studies have suggested a rise in opioid- and stimulant-involved overdoses in recent years in North America. This risk may be acute for individuals who have had contact with the criminal justice system, who are particularly vulnerable to overdose risk. Objective: To examine the association of opioid and/or stimulant use disorder diagnoses with overdose (fatal and nonfatal) among people with histories of incarceration. Design, Setting, and Participants: In this cohort study, population-based health and corrections data were retrieved from the British Columbia Provincial Overdose Cohort, which contains a 20% random sample of residents of British Columbia. The analysis included all people in the 20% random sample who had a history of incarceration between January 1, 2010, and December 31, 2014. Outcomes were derived from 5-years of follow-up data (January 1, 2015, to December 31, 2019). Statistical analysis took place from January 2022 to June 2022. Exposures: Substance use disorder diagnosis type (ie, opioid use disorder, stimulant use disorder, both, or neither), sociodemographic, health, and incarceration characteristics. Main Outcomes and Measures: Hazard ratios (HRs) are reported from an Andersen-Gill model for recurrent nonfatal overdose events and from a Fine and Gray competing risk model for fatal overdose events. Results: The study identified 6816 people (5980 male [87.7%]; 2820 aged <30 years [41.4%]) with histories of incarceration. Of these, 293 (4.3%) had opioid use disorder only, 395 (6.8%) had stimulant use disorder only, and 281 (4.1%) had both diagnoses. During follow-up, 1655 people experienced 4026 overdoses including 3781 (93.9%) nonfatal overdoses, and 245 (6.1%) fatal overdoses. In adjusted analyses, the hazard of both fatal (HR, 2.39; 95% CI, 1.48-3.86) and nonfatal (HR, 2.45; 95% CI, 1.94-3.11) overdose was highest in the group with both opioid and stimulant use disorder diagnoses. Conclusions and Relevance: This cohort study of people with a history of incarceration found an elevated hazard of fatal and nonfatal overdose among people with both opioid and stimulant use disorder diagnoses. This study suggests an urgent need to address the service needs of individuals who have had contact with the criminal justice system and who co-use opioids and stimulants.

Concurrent use of opioids and stimulants and risk of fatal overdose: A cohort study.

BACKGROUND: Stimulant use has been rising among people with opioid use disorder in recent years in North America, alongside a parallel rise in illicit drug toxicity (overdose) deaths. This study aimed to examine the association between stimulant use and overdose mortality. METHODS: Data from a universal health insurance client roster were used to identify a 20% random general population sample (aged ≥12) in British Columbia, Canada between January 1 2015 and December 31 2018 (N = 1,089,682). Provincial health records were used to identify people who used opioids and/or stimulants. Fatal overdose observed during follow-up (January 12,015- December 312,018) was retrieved from Vital Statistics Death Registry and BC Coroners Service Data. Potential confounders including age, sex, health region, comorbidities and prescribed medications were retrieved from the provincial client roster and health records. RESULTS: We identified 7460 people who used stimulants and or opioids. During follow-up there were 272 fatal overdose events. People who used both opioids and stimulants had more than twice the hazard of fatal overdose (HR: 2.02, 95% CI: 1.47-2.78, p < 0.001) compared to people who used opioids only. The hazard of death increased over time among people who used both opioids and stimulants. CONCLUSIONS: There is an urgent need to prioritize the service needs of people who use stimulants to reduce overdose mortality in British Columbia. Findings have relevance more broadly in other North American settings, where similar trends in opioid and stimulant polysubstance use have been observed.

Prevalence of co-occurring mental illness and substance use disorder and association with overdose: a linked data cohort study among residents of British Columbia, Canada.

AIMS: To estimate the treated prevalence of mental illness, substance use disorder (SUD) and dual diagnosis and the association between dual diagnosis and fatal and non-fatal overdose among residents of British Columbia (BC), Canada. DESIGN: A retrospective cohort study using linked health, income assistance, corrections and death records. SETTING: British Columbia (BC), Canada. PARTICIPANTS: A total of 921 346 BC residents (455 549 males and 465 797 females) aged 10 years and older. MEASUREMENTS: Hospital and primary-care administrative data were used to identify a history of mental illness only, SUD only, dual diagnosis or no history of SUD or mental illness (2010-14) and overdoses resulting in medical care (2015-17). We calculated crude incidence rates of non-fatal and fatal overdose by dual diagnosis history. Andersen-Gill and competing risks regression were used to examine the association between dual diagnosis and non-fatal and fatal overdose, respectively, adjusting for age, sex, comorbidities, incarceration history, social assistance, history of prescription opioid and benzodiazepine dispensing and region of residence. FINDINGS: Of the 921 346 people in the cohort, 176 780 (19.2%), 6147 (0.7%) and 15 269 (1.7%) had a history of mental illness only, SUD only and dual diagnosis, respectively; 4696 (0.5%) people experienced 688 fatal and 6938 non-fatal overdoses. In multivariable analyses, mental illness only, SUD only and dual diagnosis were associated with increased rate of non-fatal [hazard ratio (HR) = 1.8, 95% confidence interval (CI) = 1.6-2.1; HR = 9.0, 95% CI = 7.0-11.5, HR = 8.7, 95% CI = 6.9-10.9, respectively] and fatal overdose (HR = 1.6, 95% CI = 1.3-2.0, HR = 4.3, 95% CI = 2.8-6.5, HR = 4.1, 95% CI = 2.8-6.0, respectively) compared with no history. CONCLUSIONS: In a large sample of residents of British Columbia (Canada), approximately one in five people had sought care for a substance use disorder or mental illness in the past 5 years. The rate of overdose was elevated in people with a mental illness alone, higher again in people with a substance use disorder alone and highest in people with a dual diagnosis. The adjusted hazard rates were similar for people with substance use disorder only and people with a dual diagnosis.

Fatal overdoses after release from prison in British Columbia: a retrospective data linkage study.

BACKGROUND: People recently released from prison are at increased risk of preventable death; however, the impact of the current overdose epidemic on this population is unknown. We aimed to document the incidence and identify risk factors for fatal overdose after release from provincial prisons in British Columbia. METHODS: We conducted a retrospective, population-based, open cohort study of adults released from prisons in BC, using linked administrative data. Within a random 20% sample of the BC population, we linked provincial health and correctional records from 2010 to 2017 for people aged 23 years or older as of Jan. 1, 2015, who were released from provincial prisons at least once from 2015 to 2017. We identified exposures that occurred from 2010 to 2017 and deaths from 2015 to 2017. We calculated the piecewise incidence of overdose-related and all-cause deaths after release from prison. We used multivariable, mixed-effects Cox regression to identify predictors of all-cause death and death from overdose. RESULTS: Among 6106 adults released from prison from 2015 to 2017 and followed in the community for a median of 1.6 (interquartile range 0.9-2.3) years, 154 (2.5%) died, 108 (1.8%) from overdose. The incidence of all-cause death was 16.1 (95% confidence interval [CI] 13.7-18.8) per 1000 person-years. The incidence of overdose deaths was 11.2 (95% CI 9.2-13.5) per 1000 person-years, but 38.8 (95% CI 3.2-22.6) in the first 2 weeks after release from prison. After adjustment for covariates, the hazard of overdose death was 4 times higher among those who had been dispensed opioids for pain. INTERPRETATION: People released from prisons in BC are at markedly increased risk of overdose death. Overdose prevention must go beyond provision of opioid agonist treatment and naloxone on release to address systemic social and health inequities that increase the risk of premature death.

Periods of altered risk for non-fatal drug overdose: a self-controlled case series.

BACKGROUND: Being recently released from prison or discharged from hospital, or being dispensed opioids, benzodiazepines, or antipsychotics have been associated with an increased risk of fatal drug overdose. This study aimed to examine the association between these periods and non-fatal drug overdose using a within-person design. METHODS: In this self-controlled case series, we used data from the provincial health insurance client roster to identify a 20% random sample of residents (aged ≥10 years) in British Columbia, Canada between Jan 1, 2015, and Dec 31, 2017 (n=921 346). Individuals aged younger than 10 years as of Jan 1, 2015, or who did not have their sex recorded in the client roster were excluded. We used linked provincial health and correctional records to identify a cohort of individuals who had a non-fatal overdose resulting in medical care during this time period, and key exposures, including periods of incarceration, admission to hospital, emergency department care, and supply of medications for opioid use disorder (MOUD), opioids for pain (unrelated to MOUD), benzodiazepines, and antipsychotics. Using a self-controlled case series, we examined the association between the time periods during and after each of these exposures and the incidence of non-fatal overdose with case-only, conditional Poisson regression analysis. Sensitivity analyses included recurrent overdoses and pre-exposure risk periods. FINDINGS: We identified 4149 individuals who had a non-fatal overdose in 2015-17. Compared with unexposed periods (ie, all follow-up time that was not part of a designated risk period for each exposure), the incidence of non-fatal overdose was higher on the day of admission to prison (adjusted incidence rate ratio [aIRR] 2·76 [95% CI 1·51-5·04]), at 1-2 weeks (2·92 [2·37-3·61]), and 3-4 weeks (1·34 [1·01-1·78]) after release from prison, 1-2 weeks after discharge from hospital (1·35 [1·11-1·63]), when being dispensed opioids for pain (after ≥4 weeks) or benzodiazepines (entire use period), and from 3 weeks after discontinuing antipsychotics. The incidence of non-fatal overdose was reduced during use of MOUD (aIRRs ranging from 0·33 [0·26-0·42] to 0·41 [0·25-0·67]) and when in prison (0·12 [0·08-0·19]). INTERPRETATION: Expanding access to and increasing support for stable and long-term medication for the management of opioid use disorder, improving continuity of care when transitioning between service systems, and ensuring safe prescribing and medication monitoring processes for medications that reduce respiratory function (eg, benzodiazepines) could decrease the incidence of non-fatal overdose. FUNDING: Murdoch Children's Research Institute and National Health and Medical Research Council.

Comparing mortality and healthcare utilization in the year following a paramedic-attended non-fatal overdose among people who were and were not transported to hospital: A prospective cohort study using linked administrative health data.

BACKGROUND: As the overdose emergency continues in British Columbia (BC), paramedic-attended overdoses are increasing, as is the proportion of people not transported to hospital following an overdose. This study investigated risk of death and subsequent healthcare utilization for people who were and were not transported to hospital after a paramedic-attended non-fatal overdose. METHODS: Using a linked administrative health data set which includes all overdoses that come into contact with health services in BC, we conducted a prospective cohort study of people who experienced a paramedic-attended non-fatal overdose between 2015 and 2016. People were followed for 365 days after the index event. The primary outcomes assessed were all-cause mortality and overdose-related death. Additionally, we examined healthcare utilization after the index event. RESULTS: In this study, 8659 (84%) people were transported and 1644 (16%) were not transported to hospital at the index overdose event. There were 279 overdose deaths (2.7% of people, 59.4% of deaths) during follow-up. There was no significant difference in risk of overdose-related death, though people not transported had higher odds of a subsequent non-fatal overdose event captured in emergency department and outpatient records within 90 days. People transported to hospital had higher odds of using hospital and outpatient services for any reason within 365 days. CONCLUSIONS: Transport to hospital after a non-fatal overdose is an opportunity to provide care for underlying and chronic conditions. There is a need to better understand factors that contribute to non-transport, particularly among people aged 20-59 and people without chronic conditions.

Associations of Work Stress, Supervisor Unfairness, and Supervisor Inability to Speak Spanish with Occupational Injury among Latino Farmworkers.

Little is known about how psychosocial work factors such as work stress, supervisor fairness, and language barriers affect risk of occupational injury among Latino farmworkers. This study attempts to address these questions. Surveys were administered via interviews to 225 Latino thoroughbred farmworkers. Multivariable logistic regression analyses were performed to calculate odds ratios (OR) and 95% confidence intervals (CI) of occupational injury in the past year in relation to occupational characteristics. Work stress (OR 6.70, 95% CI 1.84-24.31), supervisor unfairness (OR 3.34, 95% CI 1.14-9.73), longer tenure at farm (OR 2.67, 95% CI 1.13-6.34), and supervisor inability to speak Spanish (OR 2.29, 95% CI 1.05-5.00) were significantly associated with increased odds of occupational injury. Due to the associations between work stress, supervisor unfairness, supervisor inability to speak Spanish and injury, supervisor training to improve Spanish language ability and equitable management practices is merited. Future research is needed to understand the antecedents of work stress for Latino farmworkers.

Lung cancer incidence and the strength of municipal smoke-free ordinances.

BACKGROUND: Smoke-free laws reduce disease prevalence. The impact of municipal smoke-free laws on lung cancer incidence in Kentucky was examined. The authors hypothesized that lung cancer incidence rates would be associated with the strength of smoke-free laws. METHODS: This was a secondary analysis of 83,727 Kentucky residents aged ≥ 50 years who were newly diagnosed with lung cancer from 1995 to 2014. In 2014, 33 municipalities had 1 or more smoke-free laws. County-level characteristics included adult smoking rate, sex, race/ethnicity, income, physician supply, observed radon values, and rurality. RESULTS: Individuals living in communities with comprehensive smoke-free laws were 7.9% less likely than those living in communities without smoke-free protections to be diagnosed with lung cancer. The difference in lung cancer incidence between counties with moderate/weak laws and those without laws was not significant. CONCLUSIONS: Comprehensive smoke-free laws were associated with fewer new cases of lung cancer, whereas weak or moderate smoke-free laws did not confer the same benefit. One hundred percent smoke-free laws, covering all workers and the public with few or no exceptions, may be key in reducing new cases of lung cancer. Cancer 2018;124:374-80. © 2017 American Cancer Society.

Poor safety climate, long work hours, and musculoskeletal discomfort among Latino horse farm workers.

This study investigated the prevalence of self-reported musculoskeletal discomfort (MSD) and work-related factors associated with elevated MSD among Latino thoroughbred farm workers. Participants (N = 225) were recruited using a community-based purposive sampling approach to participate in in-person interviews. Of these workers, 85% experienced MSD. MSD was divided into tertiles; the upper tertile was defined as elevated. Multivariable Poisson regression revealed associations between any elevated MSD and longer tenure on horse farms, longer work hours, and poor safety climate. Elevated neck/back MSD was associated with longer tenure, longer work hours, and poor safety climate. Elevated upper extremity MSD was associated with age and poor safety climate. Elevated lower extremity MSD was associated with longer tenure, longer work hours, and being female. Musculoskeletal discomfort is common among these workers. Improving safety climate and minimizing long work hours is recommended.

Molecular and clinical diseasome of comorbidities in exacerbated COPD patients.

The frequent occurrence of comorbidities in patients with chronic obstructive pulmonary disease (COPD) suggests that they may share pathobiological processes and/or risk factors.To explore these possibilities we compared the clinical diseasome and the molecular diseasome of 5447 COPD patients hospitalised because of an exacerbation of the disease. The clinical diseasome is a network representation of the relationships between diseases, in which diseases are connected if they co-occur more than expected at random; in the molecular diseasome, diseases are linked if they share associated genes or interaction between proteins.The results showed that about half of the disease pairs identified in the clinical diseasome had a biological counterpart in the molecular diseasome, particularly those related to inflammation and vascular tone regulation. Interestingly, the clinical diseasome of these patients appears independent of age, cumulative smoking exposure or severity of airflow limitation.These results support the existence of shared molecular mechanisms among comorbidities in COPD.

Individual and occupational characteristics associated with respiratory symptoms among Latino horse farm workers.

BACKGROUND: Latino workers are likely exposed to a variety of respiratory hazards in the horse barn, yet the potential impact of these exposures on respiratory health has not been investigated. METHODS: Using a community-based sample of 225 Latino horse farmworkers we investigated the prevalence of upper and lower respiratory symptoms and occupational characteristics associated with them. Multivariable logistic regression was used to identify factors associated with respiratory symptomology. RESULTS: Upper respiratory symptoms prevalence ranged from 24% to 45%. Half of workers reported lower respiratory symptoms. Workers with symptoms were more likely to be female and have lower levels of English understanding. Workers who never/rarely used dust masks while working in the barn experienced over two times the odds of reporting upper respiratory symptoms. CONCLUSIONS: Many Latino horse workers experienced upper and lower respiratory symptoms. Dust mask use may protect workers in this and other enclosed livestock operations from respiratory symptoms.

Association between systemic inflammatory markers and serum prostate-specific antigen in men without prostatic disease - the 2001-2008 National Health and Nutrition Examination Survey.

BACKGROUND: Serum prostate specific antigen (PSA) may be elevated in otherwise healthy men; systemic inflammation has been associated with cancer. The study of systemic inflammatory markers in men without clinical prostate disease, but with elevated PSA may characterize the subgroup of men at higher risk for subsequent prostate cancer. METHODS: We investigated the associations between systemic inflammatory markers and serum PSA in 3,164 healthy men without prostatic disease, aged >40 years, from the 2001 to 2008 U.S. National Health and Nutrition Examination Survey (NHANES). Serum total PSA levels and concentrations of serum C-reactive protein (CRP) and plasma fibrinogen, neutrophil count, lymphocyte count, and platelet count were recorded. Neutrophil-lymphocyte ratio (NLR) ratio and platelet-lymphocyte (PLR) ratio were calculated. PSA elevation was defined as levels equal or greater than 4 ng/ml. RESULTS: Elevated serum PSA (194 men, 6.1% of the total), was significantly associated with plasma fibrinogen (ORmultiv = 1.88; 95% CI, 1.09-3.25), and NLR (ORmultiv = 1.14; 95% CI, 1.03-1.26), after adjustment for age, smoking, body mass index, education, race, co-morbidities, and use of medications. CONCLUSIONS: Markers of systemic inflammation were associated with elevated PSA in men without known prostatic disease. Future studies are needed to examine these markers' relationship with prostate cancer occurrence and progression.

Variation near the region of the lipoprotein lipase gene and hypertension or blood pressure levels in Chinese.

Essential hypertension (EH) is a common late-onset disease that exhibits complex genetic heterogeneity. Human lipoprotein lipase (LPL) is a rate-limiting enzyme that regulates the catabolism of triglycerides (TG) and chylomicrons (CM). Since dyslipidemia is a common finding in hypertensive patients, the LPL gene is a logical candidate gene that could contribute to the development of hypertension. Using linkage analysis in 148 Chinese hypertensive families, we identified a region of linkage with systolic blood pressure (SBP) and diastolic blood pressure (DBP) that consisted of a 10.6-cM interval defined by markers D8S1145, D8S261, and D8S282 on chromosome 8, which maps between 31 to 41.6 cM from the 8p-telomere contained LPL gene, with statistically significant p values for the marker D8S261 (p = 0.0021 for SBP, and p = 0.0395 for DBP). In the qualitative-trait linkage analysis, evidence for linkage between the marker D8S1145 and EH was found (p = 0.0286). The transmission/disequilibrium test (TDT/S-TDT) also supported a significant linkage-disequilibrium of the allele 3 of D8S261 with EH (chi2 = 8.643, p < 0.01). Furthermore, the marker neurofilament light polypeptide (NEFL) (11 cM centromeric to the LPL gene) appeared to be in linkage with SBP and DBP (p = 0.0329 for SBP; p = 0.0319 for DBP). Additionally, two flanking markers for LPL, D8S511 (9.5 cM telomeric to the LPL gene) and D8S560 (3.2 cM centromeric to the LPL gene), also showed significant linkage with EH (p = 0.0036 for D8S511; p = 0.0115 for D8S560). Previous knowledge about the physiological involvement of LPL in blood pressure regulation and the present findings of variation near the LPL gene support the proposition that a region near the LPL gene or the LPL gene itself might contribute to the individual blood pressure variation in Chinese.

[Prevalence, awareness, treatment and control of hypertension in Chinese adults].

OBJECTIVE: To identify the prevalence, distribution, current status of awareness and control of hypertension in Chinese adult population. METHODS: A cross-sectional survey was conducted in mainland of China in 2000 - 2001 as a part of work coordinated with InterASIA Program. A total of 15,838 nationally representative subjects aged 35 to 74 were selected with multistage cluster sampling. Measurement of blood pressure was taken for all of them with three readings in a mercuric-column sphygmomanometer after resting for five minutes. Standard structured questionnaire was used to collect their histories and treatment and prevention for hypertension. A case of hypertension was defined as any person with systolic blood pressure equal to or greater than 140 mmHg, or with diastolic blood pressure equal to or greater than 90 mmHg, or being administered with antihypertensive agents. RESULTS: A total of 15,838 adults aged 35 - 74 years were included in this survey. Overall, the prevalence of hypertension was 27.2%, representing 130 million persons with hypertension nationwide as estimated. Age-specific prevalence of hypertension was 10.7%, 26.8%, 38.9% and 50.2% for women and 17.4%, 28.2%, 40.7% and 47.3% for men aged 35 - 44, 45 - 54, 55 - 64 and 65 - 74 years, respectively. Among hypertensive patients, 44.7% were aware of their high blood pressure, 28.2% were taking antihypertensive medication, and 8.1% achieved their blood pressure under control (< 140/90 mm Hg). All these data indicated that percentages of awareness, treatment and control of hypertension increased by 86.2%, 92.6% and 145.4%, respectively in the past ten years, as compared with the data in 1991. CONCLUSIONS: In the past ten years, percentages of awareness, treatment and control of hypertension in Chinese adults increased significantly, who had a relatively high prevalence of hypertension, but lower awareness and much lower percentages of treatment and control of hypertension. It is urgently needed to improve prevention, detection and treatment for hypertension in adults.

Linkage analysis of 2q14-q23 and 5q32 with blood pressure quantitative traits in Chinese sib pairs.

OBJECTIVES: Several genome-wide scans recently accomplished in the ethnic Chinese revealed a number of candidate loci possibly contributing to essential hypertension, and some appeared to be replicable in 2q14-q23 and 5q32. The current study aimed to examine the linkage of qualitative and blood pressure quantitative traits in essential hypertension with these genomic regions in a large sample of Chinese hypertensive families. METHODS: We performed a genetic analysis on 148 randomly ascertained families containing 328 affected sib pairs, grouped into two geographically distinct subsets. Five highly informative microsatellite markers (D2S151, D2S142, D5S2090, D5S413 and D5S2013) were genotyped, and linkage analyses were performed with different genetic models. RESULTS: We did not observe consistent evidence for excess allele sharing identity by descent in either of the qualitative or the quantitative test. However, higher LOD scores were found at D5S2013 in North Group subset with Haseman-Elston and maximum likelihood (ML) variance (no dominance variance, NDV) algorithms. With the ML (NDV) algorithm, the LOD was 1.410 for diastolic blood pressure at this locus, although this was not statistically significant. CONCLUSIONS: These findings provide no evidence to support a significant linkage of 2q14-q23 or 5q32 with essential hypertension or blood pressure quantitative traits in the ethnic Chinese, and indicate the aetiologic diversity and complexity of hypertension. Previous reports implied 2q14-q23 or beta 2- adrenergic receptor gene potentially linked to essential hypertension in the ethnic Chinese. To replicate these results and perform quantitative linkage analysis, we genotyped members of 148 hypertensive families with five highly informative microsatellite markers. We observed no evidence of excess allele sharing identity by descent in sib pairs, revealing a lack of linkage between 2q14-q23 or 5q32 (chromosome region harboring the gene encoding beta 2 adrenergic receptor) and hypertension in our study sample.

Biological monitoring of combined exposure to organophosphates and pyrethroids.

A total of 132 farmers were selected from two areas (J and S) for this study. In area J, the subgroups Ja (40 subjects) and Jb (36 subjects) sprayed on rice crops either the organophosphate (OP) insecticide methamidophos or the mixture methamidophos-deltamethrin (a pyrethroid, Pyr). In area S, the subgroups Sa (27 subjects) and Sb (29 subjects) sprayed on cottons either the OP methyl-parathion or the mixture methyl-parathion-deltamethrin. Groups Jc (22 subjects) and Sc (20 subjects) were non-exposed controls. Erythrocyte acetylcholinesterase (AChE) was measured by the Ellman's method before spraying, after 2-h exposure and 1 h later. Inhibition of AChE occurred after 2-h exposure to both single OP (Ja and Sa) and OP-containing mixtures (Jb and Sb) as compared with both pre-exposure and control values (Jc and Sc). A similar recovery was found in subgroups Ja, Jb, Sa and Sb 1 h after spraying, but all remained lower than the pre-exposure level. There was no difference in AChE inhibition and recovery between the single OP subgroups and the OP mixture subgroups. The inhibitory effect on AChE shown in subjects with combined OP-Pyr exposure was induced by the OP component of the insecticide mixture and to a similar extent as that induced by the single OP formulations. In addition to the fact that the OP is more potent than Pyrs, the above results might explain why the clinical manifestations of OP mixture poisonings are similar to those of single OP poisoning.