Retinal arteriolar caliber predicts incident retinopathy: the Australian Diabetes, Obesity and Lifestyle (AusDiab) study

Changes in retinal vascular caliber may reflect subclinical microvascular disease and provide prognostic information regarding risk of retinopathy. In this study, we examined the prospective association of retinal vascular caliber with retinopathy risk in an Australian population-based cohort. A total of 906 participants without retinopathy at baseline had retinal vascular caliber measured from photographs and were followed-up for 5 years for incident retinopathy. After adjusting for age, sex, systolic blood pressure, A1C, and other risk factors, individuals with wider retinal arteriolar caliber (widest 25% vs. the remaining three-quarters of the population) were more likely to develop incident retinopathy (odds ratio 4.79 [95% CI 1.57-14.58]). This association was not significant in individuals without diabetes. Venular caliber did not predict incident retinopathy. Our findings suggest that retinal arteriolar dilatation is a specific sign of diabetic microvascular dysfunction and may be a preclinical marker of diabetic retinopathy.     

Hospital-based ocular emergencies: epidemiology,treatment, and visual outcomes

Background

Ocular trauma is recognized as the leading cause of unilateral blindness. However, few studies to date have focused on the clinical features of hospital-based ocular emergencies. Effectiveness of trauma centers in treating ocular emergencies was compared with treatment in traditional community hospital emergency departments. Demographics, causes, and nature of ocular emergencies, as well as visual outcome in community hospitals emergency departments and trauma centers, were also examined.

Methods

Records of 1027 patients with ocular emergencies seen between July 2007 and November 2010 at 3 community hospitals emergency departments and 2 hospitals with level II trauma centers were retrospectively examined. Unpaired t test and Pearson χ² test were used to determine statistical significance.

Results

The incidence of patients requiring ophthalmic intervention was 77.2 per 100?000 in the community hospitals and 208.9 per 100?000 in the trauma centers. Rates of ocular emergencies were higher in middle-aged, white men. Orbital fractures were found in 86% of all orbital contusion cases in trauma centers, whereas 66.7% of patients with fall injuries and open globe diagnoses resulted in legal blindness.

Conclusions

The middle-aged, white men are more vulnerable to ocular injuries caused mainly by motor vehicle accidents. The ability of trauma centers to provide comparable increases in vision outcomes, despite treating more severe ocular emergencies, demonstrates the effectiveness of trauma centers. Patients diagnosed as having orbital contusions or who have fall injuries deserve careful evaluation because they are more likely to have more severe sight-threatening injuries.     

Growth of carbon dioxide whiskers

We report the growth of carbon dioxide (CO₂) whiskers at low temperatures (−70 °C to −65 °C) and moderate pressure (4.4 to 1.0 bar). Their axial growth was assessed by optical video analysis. The identities of these whiskers were confirmed as CO₂ solids by Raman spectroscopy. A vapor–solid growth mechanism was proposed based on the influence of the relative humidity on the growth.

Carbon dioxide (CO₂) whiskers were reported to grow at low temperatures (−70 °C to −65 °C) and moderate pressure (4.4 to 1.0 bar).     

Systemic and regional hemodynamic effects of high-dose epinephrine infusion in hypoxic piglets resuscitated with 100% oxygen

Shock and poor regional perfusion are common in asphyxiated neonates. We compared the systemic and regional hemodynamic effects of high-dose epinephrine (E) with those of dopamine combined with low-dose epinephrine (DE) infusions in a neonatal model of hypoxia-reoxygenation. Neonatal piglets (1-3 days, 1.5-2.5 kg) were acutely instrumented to continuously monitor systemic arterial pressure (SAP), pulmonary artery pressure, cardiac index (CI), and blood flows at the left common carotid, superior mesenteric, and renal arteries. Either epinephrine (1 microg.kg(-1).min(-1)) or dopamine (10 microg.kg(-1).min(-1)) and epinephrine (0.2 microg.kg(-1).min(-1)) were given for 2 h in hypoxic piglets resuscitated with 100% oxygen (n = 8 per group) in a randomized blinded fashion. Control piglets received hypoxia and reoxygenation but no catecholamine infusion (n = 7). Alveolar hypoxia (PaO2, 33-37 mmHg) caused reduced CI (89-92 vs. 171-186 mL.kg(-1).min(-1) of baseline, P < 0.05), hypotension (SAP, 28-32 mmHg) with pH 7.05 to 7.10, and decreased regional flows. Upon reoxygenation, CI and SAP improved but gradually deteriorated to 131 to 136 mL.kg(-1).min(-1) and 41 to 49 mmHg at 2 h of reoxygenation, respectively. E and DE administration similarly improved CI (167 +/- 60 and 166 +/- 55 vs. 121 +/- 35 mL.kg(-1).min(-1) of controls) and SAP (53 +/- 7 and 56 +/- 10 vs. 39 +/- 8 mmHg of controls), respectively, and the pulmonary vascular resistance (vs. controls, all P < 0.05). Heart rate and pulmonary artery pressure were not different between groups. Systemic oxygen delivery and consumption were increased in E- and DE-treated groups with no difference in extraction ratio between groups. There were no differences in regional blood flows and oxygen delivery between groups. After hyperlactatemia with hypoxia, plasma lactate levels decreased with no difference between groups. Epinephrine given as the sole agent is as effective as dopamine and low-dose epinephrine combined in treating shock and hypotension that follow the resuscitation of hypoxic neonatal piglets, with no reduction in regional perfusion.     

Interframe clutter filtering for high frequency flow imaging

This study investigates 'interframe' clutter filtering with a high frequency (HF) flow imaging system with the objective of improving the performance of HF microvascular imaging at high frame rates. An interframe filter exploits the correlation of tissue signals on the time scale of the frame rate and is, therefore, insensitive to tissue spectral broadening induced by sweeping a single element transducer over a region of tissue. In vitro experiments were conducted in a tissue-mimicking flow phantom over a range of mean flow velocities (0.5 to 70.0 mm/s). Power Doppler (PD) imaging and color flow (CF) imaging were performed for both slow (0.25 fps) and fast (20 fps) scanning acquisitions. Flow data acquired at 20 fps and interframe filtered had similar velocity and mean Doppler power values as the 0.25 fps single-frame filtered data sets. In vivo validation experiments were conducted using a 500 microm blood vessel in a human finger and detected blood flow of 2 to 3 mm/s. Further in vivo experiments examining experimental murine tumors demonstrated the feasibility of performing HF PD and CF imaging at high frame rates using interframe filtering.     

Cross-talk between Chk1 and Chk2 in double-mutant thymocytes

Chk1 is a checkpoint kinase and an important regulator of mammalian cell division. Because null mutation of Chk1 in mice is embryonic lethal, we used the Cre-loxP system and the Lck promoter to generate conditional mutant mice in which Chk1 was deleted only in the T lineage. In the absence of Chk1, the transition of CD4(-)CD8(-) double-negative (DN) thymocytes to CD4(+)CD8(+) double-positive (DP) cells was blocked due to an increase in apoptosis at the DN2 and DN3 stages. Strikingly, loss of Chk1 activated the checkpoint kinase Chk2 as well as the tumor suppressor p53 in these thymocytes. However, the developmental defects caused by Chk1 deletion were not rescued by p53 inactivation. Significantly, even though Chk1 deletion is highly lethal in proliferating tissues, we succeeded in using in vivo methods to generate Chk1/Chk2 double-knockout T cells. Analysis of these T cells revealed an interesting interaction between Chk1 and Chk2 functions that partially rescued the apoptosis of the double-mutant cells. Thus, Chk1 is both critical for the survival of proliferating cells and engages in cross-talk with the Chk2 checkpoint kinase pathway. These factors have implications for the targeting of Chk1 as an anticancer therapy.     

Ethnicity and risk factors in needle sharing among intravenous drug users in Sichuan Province, China

Combining survey and ethnographic data, this research examined differences in the risk factors associated with needle sharing amongst intravenous drug users (IDUs) in the Sichuan Province of China. A comparison was made between the province's majority Han population and its Yi minority. We developed a theoretical framework consisting of risk factors at the individual level (including risk factors such as lack of AIDS knowledge, low self-efficacy, and economic pressure), interpersonal level (having an IDU primary partner and lack of family support), and community level (social discrimination). The findings suggested that the Yi minority group was more socially disadvantaged and had a higher risk of contracting HIV than the Han group. Furthermore, the factors that put them at risk were different to those which affected the Han group. OLS regression results showed that, for Han IDUs, needle sharing was positively associated with having an IDU primary partner and with economic pressure. On the other hand, for the minority group, needle sharing was significantly associated with being male, AIDS knowledge, the lack of family support, and social discrimination. These findings highlight the need for HIV prevention work to target marginalized populations in China, such as ethnic minorities, and to tailor appropriate prevention strategies to meet the specific needs of different groups.     

Laparoscopic anterior resection

Laparoscopic colectomy for cancer is increasingly practiced worldwide in the last 2 decades. However, due to procedural complexity, laparoscopic rectal cancer excision had not proceeded at a similar pace. This article deals with the technique of laparoscopic anterior resection. Resection of rectosigmoid or upper rectal tumors is first described, followed by the more difficult sphincter-saving total mesorectal excision. We have been using and modifying this technique of laparoscopic anterior resection for rectal cancer since 1990s. In our recent review, the local recurrence rate was 7.4%, and the overall 5-year survival was 70%. Our data suggest laparoscopic resection for rectal cancer is safe and is the procedure of choice in selected patients.