Histological validation of a type 1 diabetes clinical diagnostic model for classification of diabetes.

AIMS: Misclassification of diabetes is common due to an overlap in the clinical features of type 1 and type 2 diabetes. Combined diagnostic models incorporating clinical and biomarker information have recently been developed that can aid classification, but they have not been validated using pancreatic pathology. We evaluated a clinical diagnostic model against histologically defined type 1 diabetes. METHODS: We classified cases from the Network for Pancreatic Organ donors with Diabetes (nPOD) biobank as type 1 (n = 111) or non-type 1 (n = 42) diabetes using histopathology. Type 1 diabetes was defined by lobular loss of insulin-containing islets along with multiple insulin-deficient islets. We assessed the discriminative performance of previously described type 1 diabetes diagnostic models, based on clinical features (age at diagnosis, BMI) and biomarker data [autoantibodies, type 1 diabetes genetic risk score (T1D-GRS)], and singular features for identifying type 1 diabetes by the area under the curve of the receiver operator characteristic (AUC-ROC). RESULTS: Diagnostic models validated well against histologically defined type 1 diabetes. The model combining clinical features, islet autoantibodies and T1D-GRS was strongly discriminative of type 1 diabetes, and performed better than clinical features alone (AUC-ROC 0.97 vs. 0.95; P = 0.03). Histological classification of type 1 diabetes was concordant with serum C-peptide [median < 17 pmol/l (limit of detection) vs. 1037 pmol/l in non-type 1 diabetes; P < 0.0001]. CONCLUSIONS: Our study provides robust histological evidence that a clinical diagnostic model, combining clinical features and biomarkers, could improve diabetes classification. Our study also provides reassurance that a C-peptide-based definition of type 1 diabetes is an appropriate surrogate outcome that can be used in large clinical studies where histological definition is impossible. Parts of this study were presented in abstract form at the Network for Pancreatic Organ Donors Conference, Florida, USA, 19-22 February 2019 and Diabetes UK Professional Conference, Liverpool, UK, 6-8 March 2019.

Mortality prediction following non-traumatic amputation of the lower extremity.

BACKGROUND: Patients who undergo lower extremity amputation secondary to the complications of diabetes or peripheral artery disease have poor long-term survival. Providing patients and surgeons with individual-patient, rather than population, survival estimates provides them with important information to make individualized treatment decisions. METHODS: Patients with peripheral artery disease and/or diabetes undergoing their first unilateral transmetatarsal, transtibial or transfemoral amputation were identified in the Veterans Affairs Surgical Quality Improvement Program (VASQIP) database. Stepdown logistic regression was used to develop a 1-year mortality risk prediction model from a list of 33 candidate predictors using data from three of five Department of Veterans Affairs national geographical regions. External geographical validation was performed using data from the remaining two regions. Calibration and discrimination were assessed in the development and validation samples. RESULTS: The development sample included 5028 patients and the validation sample 2140. The final mortality prediction model (AMPREDICT-Mortality) included amputation level, age, BMI, race, functional status, congestive heart failure, dialysis, blood urea nitrogen level, and white blood cell and platelet counts. The model fit in the validation sample was good. The area under the receiver operating characteristic (ROC) curve for the validation sample was 0·76 and Cox calibration regression indicated excellent calibration (slope 0·96, 95 per cent c.i. 0·85 to 1·06; intercept 0·02, 95 per cent c.i. -0·12 to 0·17). Given the external validation characteristics, the development and validation samples were combined, giving a total sample of 7168. CONCLUSION: The AMPREDICT-Mortality prediction model is a validated parsimonious model that can be used to inform the 1-year mortality risk following non-traumatic lower extremity amputation of patients with peripheral artery disease or diabetes.

Predicting reamputation risk in patients undergoing lower extremity amputation due to the complications of peripheral artery disease and/or diabetes.

BACKGROUND: Patients undergoing amputation of the lower extremity for the complications of peripheral artery disease and/or diabetes are at risk of treatment failure and the need for reamputation at a higher level. The aim of this study was to develop a patient-specific reamputation risk prediction model. METHODS: Patients with incident unilateral transmetatarsal, transtibial or transfemoral amputation between 2004 and 2014 secondary to diabetes and/or peripheral artery disease, and who survived 12 months after amputation, were identified using Veterans Health Administration databases. Procedure codes and natural language processing were used to define subsequent ipsilateral reamputation at the same or higher level. Stepdown logistic regression was used to develop the prediction model. It was then evaluated for calibration and discrimination by evaluating the goodness of fit, area under the receiver operating characteristic curve (AUC) and discrimination slope. RESULTS: Some 5260 patients were identified, of whom 1283 (24·4 per cent) underwent ipsilateral reamputation in the 12 months after initial amputation. Crude reamputation risks were 40·3, 25·9 and 9·7 per cent in the transmetatarsal, transtibial and transfemoral groups respectively. The final prediction model included 11 predictors (amputation level, sex, smoking, alcohol, rest pain, use of outpatient anticoagulants, diabetes, chronic obstructive pulmonary disease, white blood cell count, kidney failure and previous revascularization), along with four interaction terms. Evaluation of the prediction characteristics indicated good model calibration with goodness-of-fit testing, good discrimination (AUC 0·72) and a discrimination slope of 11·2 per cent. CONCLUSION: A prediction model was developed to calculate individual risk of primary healing failure and the need for reamputation surgery at each amputation level. This model may assist clinical decision-making regarding amputation-level selection.

Systematic reanalysis of genomic data improves quality of variant interpretation.

As genomic sequencing expands, so does our knowledge of the link between genetic variation and disease. Deeper catalogs of variant frequencies improve identification of benign variants, while sequencing affected individuals reveals disease-associated variation. Accumulation of human genetic data thus makes reanalysis a means to maximize the benefits of clinical sequencing. We implemented pipelines to systematically reassess sequencing data from 494 individuals with developmental disability. Reanalysis yielded pathogenic or likely pathogenic (P/LP) variants that were not initially reported in 23 individuals, 6 described here, comprising a 16% increase in P/LP yield. We also downgraded 3 LP and 6 variants of uncertain significance (VUS) due to updated population frequency data. The likelihood of identifying a new P/LP variant increased over time, as ~22% of individuals who did not receive a P/LP variant at their original analysis subsequently did after 3 years. We show here that reanalysis and data sharing increase the diagnostic yield and accuracy of clinical sequencing.

Abundant and stable char residues in soils: implications for soil fertility and carbon sequestration.

Large-scale soil application of biochar may enhance soil fertility, increasing crop production for the growing human population, while also sequestering atmospheric carbon. But reaching these beneficial outcomes requires an understanding of the relationships among biochar's structure, stability, and contribution to soil fertility. Using quantitative (13)C nuclear magnetic resonance (NMR) spectroscopy, we show that Terra Preta soils (fertile anthropogenic dark earths in Amazonia that were enriched with char >800 years ago) consist predominantly of char residues composed of ~6 fused aromatic rings substituted by COO(-) groups that significantly increase the soils' cation-exchange capacity and thus the retention of plant nutrients. We also show that highly productive, grassland-derived soils in the U.S. (Mollisols) contain char (generated by presettlement fires) that is structurally comparable to char in the Terra Preta soils and much more abundant than previously thought (~40-50% of organic C). Our findings indicate that these oxidized char residues represent a particularly stable, abundant, and fertility-enhancing form of soil organic matter.

Lung function loss in relation to silica dust exposure in South African gold miners.

OBJECTIVE: To estimate exposure-response relationships between respirable dust, respirable quartz and lung function loss in black South African gold miners. METHODS: 520 mineworkers aged >37 years were enrolled in a cross-sectional study. Gravimetric dust measurements were used to calculate cumulative respirable dust and quartz exposures. Excess lung function loss was defined as predicted minus observed forced expiratory volume in one second (FEV(1)) and forced vital capacity (FVC). The association between excess loss and exposure was estimated, adjusting for smoking, tuberculosis and silicosis. RESULTS: Mean service length was 21.8 years, mean respirable dust 0.37 mg/m(3) and mean respirable quartz 0.053 mg/m(3). After adjustment, 1 mg-yr/m(3) increase in cumulative respirable dust exposure was associated with 18.7 ml mean excess loss in FVC [95% confidence interval (CI) 0.3, 37.1] and 16.2 ml in FEV1 (95% CI -0.3, 32.6). Mean excess loss with silicosis was 224.1 ml in FEV1 and 123.6 ml in FVC; with tuberculosis 347.4 ml in FEV1 and 264.3 ml in FVC. CONCLUSION: Despite a healthy worker effect, lung function loss was demonstrable whether due to silicosis, tuberculosis or an independent effect of dust. A miner working at a respirable dust intensity of 0.37 mg/m(3) for 30 years would lose on average an additional 208 ml in FVC (95% CI 3, 412) in the absence of other disease, an impact greater than that of silicosis and comparable to that of tuberculosis. Improved dust control on the South African gold mines would reduce the risk of silicosis, tuberculosis and lung function impairment.

Opioid-like analgesia in defeated mice.

Mice exposed to repeated attacks by other mice showed decreased nociception in response to radiant heat focused on their tails. This form of analgesia was blocked by centrally acting opiate antagonists and was not observed in morphine-tolerant mice; furthermore, mice repeatedly subjected to defeat. Mice of the CXBK strain, which respond weakly to morphine, displayed only moderate analgesia following defeat. These findings suggest that endogenous opioid-mediated analgesic mechanisms are readily activated by situations involving biologically significant forms of stress, such as defeat.

A retrospective time trend study of firearm and non-firearm homicide in Cape Town from 1994 to 2013.

BACKGROUND: Gunshot injuries from interpersonal violence are a major cause of mortality. In South Africa (SA), the Firearms Control Act of 2000 sought to address firearm violence by removing illegally owned firearms from circulation, stricter regulation of legally owned firearms, and stricter licensing requirements. Over the last few years, varied implementation of the Act and police corruption have increased firearm availability. OBJECTIVES: To investigate whether changes in firearm availability in SA were associated with changes in firearm homicide rates. METHODS: This was a retrospective time trend study (1994 - 2013) using postmortem data. Time trends of firearm and non-firearm homicide rates were analysed with generalised linear models. Distinct time periods for temporal trends were assigned based on a priori assumptions regarding changes in the availability of firearms. RESULTS: Firearm and non-firearm homicide rates adjusted for age, sex and race exhibited different temporal trends. Non-firearm homicide rates either decreased or remained stable over the entire period. Firearm homicide increased at 13% annually from 1994 through 2000, and decreased by 15% from 2003 through 2006, corresponding with changes in firearm availability in 2001, 2003, 2007 and 2011. A 21% annual increase in firearm homicide after 2010 coincided with police fast-tracking new firearm licence applications. Cape Town's coloured population experienced a significantly greater increase than other population groups following additional exposure to illegal firearms from 2007. CONCLUSIONS: The strong association between firearm availability and homicide, and the reversal of a decreasing firearm homicide trend during a period of lax enforcement, provide further support for the association between reduced firearm homicide and stricter regulation.

Tuberculosis and silica exposure in South African gold miners.

AIMS: To examine the effect of silica exposure, in the absence of silicosis, on the prevalence of pulmonary tuberculosis (PTB), which is epidemic among South African gold miners. METHODS: Cross-sectional study of 520 gold miners over 37 years of age. Length of service, and cumulative and average dust and quartz exposure indices were derived for each miner. Chest radiographs were read for PTB by two NIOSH "B" readers. PTB was defined as a self-reported history of PTB or PTB on chest radiograph. Logistic regression was used to adjust for age, smoking, and silicosis. PTB effects of different exposure metrics for silica, scaled on their interquartile range (IQR), were compared. RESULTS: Means (ranges) were: age 46.7 (37.1-59.9) years; length of service 21.8 (6.3-34.5) years; average intensity of respirable quartz 0.053 (0-0.095) mg/m3. PTB prevalence was 19.4% (95% CI 16.0 to 22.8) on history alone, and 35.2% (95% CI 31.1 to 39.3) on history or on chest radiograph. Length of service was poorly predictive of PTB, while all exposure indices which included dust or quartz yielded prevalence odds ratios (PORs) of approximately 1.4 (95% CI approximately 1.1 to 1.8) for changes of one interquartile range in exposure. Controlling for silicosis--by adjustment or restriction--did not modify these results. Drillers and winch operators had the highest PTB prevalences and the highest dust and silica exposures. CONCLUSION: Older in-service gold miners in South Africa have a high prevalence of PTB, which is significantly associated with dust and silica exposure, even in the absence of silicosis. Limitations include a survivor workforce and the use of cumulative exposures based on current exposures. Dust control is an important component in control of the PTB epidemic in South African gold mines.

Combining diagnostic test results to increase accuracy.

When multiple diagnostic tests are performed on an individual or multiple disease markers are available it may be possible to combine the information to diagnose disease. We consider how to choose linear combinations of markers in order to optimize diagnostic accuracy. The accuracy index to be maximized is the area or partial area under the receiver operating characteristic (ROC) curve. We propose a distribution-free rank-based approach for optimizing the area under the ROC curve and compare it with logistic regression and with classic linear discriminant analysis (LDA). It has been shown that the latter method optimizes the area under the ROC curve when test results have a multivariate normal distribution for diseased and non-diseased populations. Simulation studies suggest that the proposed non-parametric method is efficient when data are multivariate normal.The distribution-free method is generalized to a smooth distribution-free approach to: (i) accommodate some reasonable smoothness assumptions; (ii) incorporate covariate effects; and (iii) yield optimized partial areas under the ROC curve. This latter feature is particularly important since it allows one to focus on a region of the ROC curve which is of most relevance to clinical practice. Neither logistic regression nor LDA necessarily maximize partial areas. The approaches are illustrated on two cancer datasets, one involving serum antigen markers for pancreatic cancer and the other involving longitudinal prostate specific antigen data.

[Early or late umbilical cord clamping? A systematic review of the literature]. / 'Pinzamiento precoz o tardío del cordón umbilical? Una revisión sistemática de la literatura médica.

INTRODUCTION: There is wide variability in clinical practice in the moment of clamping the umbilical cord. Opinions in the medical community differ on the harm and/or benefits, both for the mother and for the newborn, of early versus late cord clamping. Currently, the debate among those who defend and/or criticize one or other of these practices continues. The aim of this study was to evaluate the effects of early versus late clamping of the umbilical cord in full-term newborns on maternal and neonatal outcomes. MATERIAL AND METHODS: A literature search of randomized clinical trials was carried out in the Cochrane Library, MEDLINE and Lilacs. It was completed with a hand search of references in relevant articles. All randomized controlled clinical trials of good methodological quality that compared early versus late cord clamping in term newborns were selected. RESULTS: Of seven identified studies, four had the required characteristics for inclusion in this systematic review. Comparison of early versus late clamping in these studies revealed that late clamping could diminish the prevalence of children with low iron reserves at 3 months of age by 50%, but this result comes from a study that lost more than 40% of the patients during follow-up. The results concerning anemia at 3 months of age showed statistical heterogeneity since the two studies that analyzed this outcome had opposite results. For other outcomes such as birth weight, Apgar < 5, and tachypnea the studies were too small for significant differences to be detected. CONCLUSIONS: This review shows that there is no clear evidence for defending any of the modalities of cord clamping in full-term newborns. Further research is needed to identify the best moment for cord clamping.

Weight loss intention, dietary behaviors, and barriers to dietary change in veterans with lower extremity amputations.

BACKGROUND: Obesity is thought to be highly prevalent in persons with lower extremity amputations (LEAs) and can impair physical and social functioning. OBJECTIVE: The aim of this study was to determine the prevalence of weight loss intention, weight loss strategies, dietary patterns, and barriers to making dietary changes, and their associations with body mass index (BMI, kg/m(2)), amputation characteristics, health status, and socioeconomic factors. METHODS: We conducted a cross-sectional study (n = 150) using data from a self-administered questionnaire. RESULTS: 43% of participants were obese and 48% were trying to lose weight; 83% of those trying to lose weight reported trying to "eat differently", but only 7% were following a comprehensive weight loss program involving dietary changes, physical activity, and behavioral counseling. 21% of participants reported ≥ 6 barriers to changing their eating habits (e.g., habit, too little money, stress/depression). Obesity was associated with younger age, lower physical health scores, hypertension, arthritis, and diabetes. Compared to those not trying to lose weight, a greater proportion of those trying to lose weight had a BMI ≥ 35 kg/m(2), age <55 years, higher physical and mental health scores, and more frequent consumption of vegetables, beans, chicken, and fish. CONCLUSIONS: Though over half of overweight and obese individuals with LEA were trying to lose weight, few reported following a comprehensive program to lose weight, which may indicate an unmet need for services for this group. To be effective, these programs will need to address the complex physical and mental health challenges that many of these individuals face.

Recent trends in testosterone testing, low testosterone levels, and testosterone treatment among Veterans.

Low serum testosterone (T) is common and increasingly prevalent with increased age. Recent studies report an 'epidemic' of T prescribing and concern about unnecessary T treatment. We investigated the number of men tested for T, the prevalence of low serum T levels, and initiation of T treatment among those with low T levels in men treated at Veterans Affairs (VA) facilities in the Northwest US (VISN 20). We identified male Veterans aged 40-89 years and examined yearly proportions of men tested for T, found to have low T levels (total T < 280 ng/dL, free T < 34 pg/mL, or bioavailable T < 84 ng/dL), and subsequently treated with T from 2002 to 2011. We excluded men who had T treatment in the year prior and men with diagnoses of prostate or breast cancer. Treatment initiation was defined as the first prescription for T within a year following a low T test. From 2002 to 2011, the yearly population of eligible men in VISN 20 increased from 129 247 to 163 572. The proportion of men who had serum T tests increased from 3.2% in 2002 to 5.8% in 2011. Among the tested men, the percentage of men with low T levels increased from 35.0 to 47.3%. However, the proportion of men with low T levels who were given T treatment within a year decreased from 31.0 to 28.0%. Despite large increases in T testing, and detection of men with low T levels, there was a slight decrease in the proportion of men with low T levels who were treated with T. The decrease in T treatment during this time period contrasts with other studies and may be related to higher comorbidity in Veterans and/or VA formulary restrictions on the use of transdermal T formulations.

Cofactors for the acquisition of HIV-1 among heterosexual men: prospective cohort study of trucking company workers in Kenya.

OBJECTIVE: To determine the prevalence, incidence, and correlates of HIV-1 infection in a cohort of east African trucking company employees. METHODS: HIV-1-seronegative trucking company employees were enrolled in a prospective cohort study and evaluated at 3 monthly intervals for HIV-1 seroconversion, sexually transmitted diseases, and sexual behavior. RESULTS: The baseline seroprevalence of HIV-1 among 1500 trucking company employees was 17.8%. Among 752 HIV-1-seronegative men who were followed, the HIV-1 annual seroincidence was 3.1%. In univariate analysis, HIV-1 acquisition was associated with age under 25 years, 10 years or less of sexual activity, occupation as a driver/driver's assistant, occupational travel for more than 14 days per month, religion other than Christian or Muslim, uncircumcised status, sex with a prostitute, sex with a girlfriend/casual partner, extramarital sex, and enrollment seropositivity to Treponema pallidum, Haemophilus ducreyi, and Herpes simplex virus type 2 (all P values < or = 0.05). Using multivariate analysis, HIV-1 acquisition was independently associated with 10 years or less of sexual activity (hazard rate ratio (HRR) 2.0, 95% confidence interval (CI) 1.0-4.3), occupation as a driver/driver's assistant (HRR 3.9, 95% CI 1.7-9.0), religion other than Christian or Muslim (HRR 6.1, 95% CI 1.4-25.7), uncircumcised status (HRR 2.3, 95% CI 1.0-5.0), and unprotected sex with a prostitute (HRR 2.8, 95% CI 1.1-7.0). CONCLUSIONS: Trucking company employees had a high HIV-1 seroprevalence rate at enrollment and a high HIV-1 seroincidence during follow-up. Risk factors for HIV-1 seroconversion included years of sexual activity, occupation, religion, uncircumcised status, and unprotected sex with a prostitute. This population is an appropriate target for HIV-1 prevention trials and behavioral interventions.

The utility of apolipoprotein E genotyping in the diagnosis of Alzheimer disease in a community-based case series.

CONTEXT: A recent collaborative study found that apolipoprotein E (APOE) genotype, in conjunction with the clinical diagnosis of Alzheimer disease (AD), was useful in improving diagnostic specificity (correctly not diagnosing AD) relative to the clinical diagnosis alone. Since these samples are particularly enriched with patients with AD and the APOE epsilon4 allele, results may not be generalizable to patients seen in the general medical community. OBJECTIVE: To evaluate the diagnostic utility of the APOE genotype in diagnosing AD in a community-based case series from the largest health maintenance organization in an urban area. DESIGN: We examined the effect of including APOE genotype on the diagnosis of AD in a community-based case series of patients presenting with memory complaints. PATIENTS: Clinical and neuropathologic diagnoses and APOE genotype were obtained from 132 patients who underwent evaluation for dementia and subsequent autopsy. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values given various combinations of clinical diagnoses and the presence of an APOE epsilon4 allele. RESULTS: Of the 132 patients, 94 had neuropathologically confirmed AD, yielding a prevalence of 71%. The clinical diagnosis alone yielded a sensitivity of 84%, an estimated specificity of 50%, and positive and negative predictive values of 81% and 56%, respectively. The presence of an epsilon4 allele alone was associated with an estimated sensitivity of 59%, specificity of 71%, and positive and negative predictive values of 83% and 41%, respectively. Using the presence of clinical AD and an epsilon4 allele decreased the sensitivity to 49% and increased the specificity to 84%. The positive and negative predictive values were 88% and 40%, respectively. Alternatively, the clinical diagnosis of AD or the presence of an epsilon4 allele in individuals not meeting clinical criteria for AD increases the estimated sensitivity to 94% but decreases the specificity to 37%. The positive and negative predictive values were 79% and 70%, respectively. The changes in the sensitivity and specificity for the combined tests relative to clinical diagnosis alone offset each other. For lower prevalence communities, the positive predictive value will be much lower than those observed herein. CONCLUSIONS: Our findings do not support the use of APOE genotyping alone in the diagnosis of AD in the general medical community. Although the presence of an epsilon4 allele in older persons with clinical AD increased the probability of having AD and the absence of an epsilon4 allele in this group decreased the probability of having AD, the association is not strong enough in the differential diagnosis of non-Alzheimer dementia and AD.

Effects of naloxone and naltrexone on drug-induced hypothermia in mice.

The hypothermia produced by injecting apomorphine into mice was potentiated by morphine; it was antagonized by haloperidol, by naloxone and by naltrexone. The hypothermic responses to morphine, chlorpromazine and ethanol were also blocked by naltrexone. However, naltrexone potentiated the hypothermic response to pentobarbital. Tolerance to morphine, produced by subcutaneous implantation of a morphine pellet, was accompanied by cross-tolerance to apomorphine-induced hypothermia. Animals made tolerant to apomorphine were not tolerant to morphine-induced hypothermia. The dopamine supersensitivity resulting from chronic treatment with haloperidol potentiated the hypothermic response to apomorphine but not to morphine. These results suggest that endogenous opioids may serve as mediators in the control of thermoregulation by dopamine.

Sex and strain differences in response to cocaine.

After pretreatment with phenobarbital, female B6AF1 mice showed considerably higher serum glutamic oxaloacetic transaminase (SGOT) elevations and more periportal necrosis from a single injection of cocaine than males. This sex difference was androgen dependent. Castration or treatment with flutamide made males respond like females, while testosterone made females behave like males. There was no significant sex difference in enzymes of cocaine metabolism. When the mice were induced by exposure to pine bedding, males showed higher SGOT elevations and more centrilobular necrosis after cocaine than females. In this case, the sex difference could be attributed to increased levels of cytochrome P-450 and cocaine N-demethylase in liver microsomes. BALB/cBy mice on pine bedding showed much less liver damage from cocaine than B6AF1 mice, but they were more sensitive to norcocaine and N-hydroxynorcocaine. This difference was correlated with low levels of cocaine N-demethylase in the BALB/cBy mice. Liver microsomes from phenobarbital-induced BALB/cBy mice had less norcocaine N-hydroxylase activity than those from B6AF1 mice. These studies demonstrate that the pattern of sex and strain differences in liver damage from cocaine depends on the inducing agent and can be related to a large extent to the microsomal enzymes induced by that agent.

A preliminary statistical examination of the effects of uncertainty and variability on environmental regulatory criteria for ozone.

Basing the quantitative expression of environmental regulatory standards and associated compliance criteria on statistical principles has recently received attention in Europe, most visibly in a study by the UK Royal Commission on Environmental Pollution. These issues are timely for consideration in the USA, where a recent periodic review of National Ambient Air Quality Standards (NAAQS) has led to revision of the regulatory standards for ambient ozone and particulate matter. Salient statistical issues include accounting for errors of the first and second kind due to sampling and measurement error. These issues appear routine statistically and also may seem absent from regulations, but neither is necessarily the case. This paper is directed towards developing a methodology for examining the problem of dealing with uncertainty and variation in environmental regulations and compliance criteria. Our approach is illustrated through statistical analysis of the (old) 1 hour and the (new) 8 hour standards for ambient ozone, based on intensive monitoring in California's San Joaquin Valley during summer 1990 performed under the SARMAP Project. This paper presents preliminary findings based on quantifying measurement error or precision in terms of small-scale spatial and temporal variability, laying the groundwork for future work.

Naloxone injections into the periaqueductal grey area and arcuate nucleus block analgesia in defeated mice.

In a situation of social conflict, mice that are defeated by an opponent exhibit a marked analgesia. Microinjections of naloxone (1 or 10 micrograms) into the periaqueductal grey area (PAG) or into the region of the arcuate nucleus prior to the defeat prevented the emergence of analgesia. Microinjections of morphine (5 micrograms) into these sites had previously been shown to produce profound analgesia. Mice whose adrenals were removed rapidly developed analgesia when attacked by a stimulus animal. Injection of naloxone into PAG also antagonized defeat-induced analgesia in adrenalectomized mice. These observations indicate that sites and processes in the brain rather than in the periphery are responsible for the development of analgesia in mice that are subjected to social defeat.