Peak BMD assessment in a Chinese infantry recruit group

Peak bone mass is an important factor influencing the occurrence of osteoporosis and osteoporotic fracture in adulthood. We measured the areal bone mineral density (BMD) in a Chinese male infantry recruit group ranging in age from 17 to 23 years and subsequently assessed peak BMD at the lumbar vertebrae and hip. This study included 812 Chinese men of Han ethnicity from 11 provinces and municipalities of China. The BMD, bone mineral content and the bone area of the lumbar vertebrae (L1-4), left femoral neck and total hip were measured using dual-energy X-ray absorptiometry. Height, weight, waist and hip circumference were also measured at the same time. BMD at the lumbar vertebrae, femoral neck and total hip reached a plateau at 22 years of age. The peak value of BMD at these 3 sites was 1.209±0.175, 1.098±0.177 and 1.122±0.151 (g/cm2), respectively. Stepwise regression analysis showed that age and weight most contributed to the variance in BMD (P<0.001). The average age when reaching peak BMD in this study is earlier than the ages reported in previous studies, and the value of peak BMD is higher than that reported previously in Chinese males. This study provides the newest peak BMD data on Chinese men.

In vivo evaluation of quantitative MR angiography in a canine carotid artery stenosis model

BACKGROUND AND PURPOSE

Large-vessel cerebral blood flow quantification has emerged as a potential predictor of stroke risk. QMRA uses phase-contrast techniques to noninvasively measure vessel flows. To evaluate the in vivo accuracy of QMRA for measuring the effects of progressive arterial stenosis, we compared this technique with invasive flow measurements from a sonographic transit-time flow probe in a canine model.

MATERIALS AND METHODS

A sonographic flow probe was implanted around the CCA of hound dogs (n = 4) under general anesthesia. Pulsatile blood flow and arterial pressure were continuously recorded during CCA flow measurements with QMRA. A vascular tourniquet was applied around the CCA to produce progressive stenosis and varying flow rates. Statistical comparisons were made by using the Pearson product moment correlation coefficient.

RESULTS

A total of 60 paired CCA flow measurements were compared. Mean blood flows ranged between 21 and 691 mL/min during QMRA acquisition as measured by the flow probe. The correlation coefficients between flow probe and QMRA measurements for mean, maximum, and minimum volume flow rates were 0.99 (P < .0001), 0.98 (P < .0001), and 0.96 (P < .0001), respectively. The overall proportional difference between the 2 techniques was 7.8 ± 1%. Measurements at higher flow rates and in the absence of arterial stenosis had the lowest PD.

CONCLUSIONS

Noninvasive CCA flow measurements by using QMRA are accurate compared with invasive flow-probe measurements in a canine arterial flow model with stenosis and may be useful for the evaluation of the hemodynamic effects of stenosis caused by cerebrovascular atherosclerosis.

Ultrasound-guided foam sclerotherapy of the great saphenous vein with sapheno-femoral ligation compared to standard stripping: a prospective clinical study

AIM

This study is a prospective randomized controlled trial comparing ultrasound-guided foam sclerotherapy of the great saphenous vein (GSV) combined with sapheno-femoral junction (SFJ) ligation to standard stripping surgery. Primary endpoints were patient recovery period, postoperative pain, quality of life and recurrence rate and secondary end points were frequency of complications on the two arms of the trial.

METHODS

Sixty consecutive patients with incompetence of the GSV resulting in varicose veins were prospectively randomized into 2 groups of 30, treated by SFJ ligation and either ultrasound-guided foam sclerotherapy or standard stripping of the GSV. The study protocol included history, physical examination, assignment of CEAP class, assessment of the Aberdeen varicose vein questionnaire (AVVQ) and colour Duplex ultrasound.

RESULTS

All treatments were completed as intended. The time taken to complete treatment was shorter in the foam sclerotherapy plus SFJ ligation group as compared to standard stripping: 43 min vs. 65 min (P<0.01, Mann-Whitney). Less analgesic use postoperatively was recorded in the foam sclerotherapy group. Median time to return to normal activities was significantly reduced in the foam sclerotherapy group (3 days) compared to the surgical group (6 days) (P<0.01, Mann-Whitney). The median overall cost of the procedure in the sclerotherapy group was 3143RMB, and was 3638RMB in the conventional surgery (P=0.235, Mann-Whitney). At 3 months, median CEAP class dropped from four preoperatively to one following treatment in both groups (p<0.01, Wilcoxon test). After 6 months, in the foam sclerotherapy group five patients (20%) needed further sessions of foam sclerotherapy, resulting in a short-term closure rate of 80%. And the short-term obliteration rate was 89.5% in the conventional surgery group.

CONCLUSION

Ultrasound guided sclerotherapy combined with sapheno-femoral ligation involved a shorter treatment time, less postoperative discomfort and resulted in more rapid recovery compared to conventional GSV stripping.

Association of the C47T polymorphism in SOD2 with diabetes mellitus and diabetic microvascular complications: a meta-analysis

AIMS/HYPOTHESIS

A meta-analysis was performed to assess the association of C47T (rs4880) (also called Val16Ala) polymorphism in SOD2 gene with reduced risk of diabetes mellitus, including type 1 and type 2 diabetes, and diabetic microvascular complications (DMI) including diabetic nephropathy, diabetic retinopathy and diabetic polyneuropathy.

METHODS

A comprehensive search was conducted to identify all case-control or cohort design studies of the above-mentioned associations. The fixed or random effect pooled measure was selected on the basis of homogeneity test among studies. Heterogeneity among studies was evaluated using the I (2). Meta-regression and the 'leave one out' sensitive analysis of Patsopoulos et al. were used to explore potential sources of between-study heterogeneity. Publication bias was estimated using modified Egger's linear regression test as proposed by Harbord et al.

RESULTS

Seventeen articles were included. After excluding articles that deviated from Hardy-Weinberg equilibrium in cases and/or in controls, and were also the key contributors to between-study heterogeneity, the meta-analysis showed a significant association of the C allele with reduced risk of DMI in dominant (OR 0.788, 95% CI 0.680-0.914), recessive (OR 0.808, 95% CI 0.685-0.953) and codominant (OR 0.828, 95% CI 0.751-0.913) models. It also showed a significant association with reduced risk of diabetic nephropathy in the dominant model (OR 0.801, 95% CI 0.664-0.967), and reduced risk of diabetic retinopathy in the dominant (OR 0.601, 95% CI 0.423-0.855), recessive (OR 0.548, 95% CI 0.369-0.814) and codominant (OR 0.651, 95% CI 0.517-0.820) models.

CONCLUSIONS/INTERPRETATION

The meta-analysis suggested that C allele of C47T polymorphism in SOD2 gene has protective effects on risk of DMI, diabetic nephropathy and diabetic retinopathy. This risk needs to be confirmed by further studies.

A neural network model of normal and abnormal auditory information processing

The ability of the brain to attenuate the response to irrelevant sensory stimulation is referred to as sensory gating. A gating deficiency has been reported in schizophrenia. To study the neural mechanisms underlying sensory gating, a neuroanatomically inspired model of auditory information processing has been developed. The mathematical model consists of lumped parameter modules representing the thalamus (TH), the thalamic reticular nucleus (TRN), auditory cortex (AC), and prefrontal cortex (PC). It was found that the membrane potential of the pyramidal cells in the PC module replicated auditory evoked potentials, recorded from the scalp of healthy individuals, in response to pure tones. Also, the model produced substantial attenuation of the response to the second of a pair of identical stimuli, just as seen in actual human experiments. We also tested the viewpoint that schizophrenia is associated with a deficit in prefrontal dopamine (DA) activity, which would lower the excitatory and inhibitory feedback gains in the AC and PC modules. Lowering these gains by less than 10% resulted in model behavior resembling the brain activity seen in schizophrenia patients, and replicated the reported gating deficits. The model suggests that the TRN plays a critical role in sensory gating, with the smaller response to a second tone arising from a reduction in inhibition of TH by the TRN.