Treatment effect estimators for count data models

In this paper, we consider a switching regression model with count data outcomes, where the possible outcome differs across two alternate states and individuals endogenously select one of the states. We assume lognormal latent heterogeneity. Building on the switching regression model, we derive estimators of various treatment effects: the average treatment effect, the average treatment effect on the treated, the local average treatment effect, and the marginal treatment effect. We illustrate an application that examines the effects of public insurance on the number of doctor visits using the data employed by previous studies.     

常州地区医院制剂室空气中尘粒和细菌总数的检测

在检测的常州地区１４所医院制剂室的超净工作台与洁净间空气中，细菌总数未超标者仅有１所，空气中尘粒数均未超标者亦仅７所。为此，应加强对制剂室防止空气污染的管理与监测。     

Experimental basis of standardized specimen collection: the effect of the site of venipuncture on the blood picture, the white blood cell differential count, and the serum albumin concentration

The effect of the specimen collection site on blood picture and WBC differential count was investigated in 13 and 25 volunteers, respectively. Lower values were found for the mature neutrophils and higher monocyte values in ear and finger blood compared to venous blood. There were no statistically significant differences in the WBC differential count values found in the ear and finger specimens. A higher S-Alb concentration was found in ear and finger specimens compared to venous blood. The average WBC concentration was higher in the ear and finger specimens than in the venous blood (7.66 x 10(9)/l, 7.11 x 10(9)/l and 6.88 x 10(9)/l, respectively). Also the platelet concentration exhibited a statistically significant difference, the mean concentrations being 273 x 10(9)/l, 260 x 10(9)/l and 231 x 10(9)/l in the vein, finger and ear specimens, respectively. The differences found are partly explained by peripheral ultrafiltration of intravascular fluid, leading to haemoconcentration, and partly by the different properties of different white blood cells. In conclusion, the specimens for blood picture and WBC differential count should always be obtained from the same site, especially in follow-up cases.     

Inverse correlation between coronary and retinal blood flows in patients with normal coronary arteries and slow coronary blood flow

Background

The “Slow Coronary Flow” (SCF) phenomenon in the presence of angiographically normal coronaries is attributed to microvascular and endothelial dysfunction. The microcirculation can be non-invasively assessed by measuring retinal blood flow velocity.The aim of the present study was to evaluate the efficacy of the “Retinal Functional Imager” (RFI) device as a noninvasive method of diagnosing patients with slow coronary flow.

Methods

Coronary blood flow velocity assessed by corrected TIMI Frame Count and retinal arterioles blood flow assessed by RFI were measured in 28 consecutive patients with normal coronary arteries. The patients were divided into 2 groups: a slow coronary flow (SCF) and a normal coronary flow (NCF) groups.

Results

Inverse correlation was found between retinal and coronary blood flows so that higher retinal arterial flow velocity was observed in the SCF group (3.8 ± 1.1 mm/s vs. 2.9 ± 0.61 mm/s, respectively, p = 0.022). RFI provided 73% sensitivity and 77% specificity for diagnosing SCF using ROC analysis. Additionally, patients with SCF had higher values of serum LDL cholesterol (104.7 ± 18.93 mg/dl vs. 81.55 ± 14.62 mg/dl in NCF, p = 0.005), Glucose (96.9 ± 23.0 mg/dl vs. 83.55 ± 9.7 mg/dl in NCF, p = 0.024), and lower percentage of statin consumption (40.0% vs. 76.9% in NCF, p = 0.049).

Conclusions

Slow coronary blood flow can be non-invasively diagnosed with Retinal Functional Imager. Patients with normal coronary arteries and slow coronary blood flow have high retinal arteriolar blood flow. Early non-invasive diagnosis of SCF might help detect individuals who are at higher risk to develop coronary atherosclerosis, and to provide them with early preventive measures.