Intraoperative Fluorescein Staining of Cryopreserved Amniotic Membrane Grafts to Improve Visualization During and After Pterygium Surgery: A Novel Technique.

PURPOSE: To describe a new method of enhancing the visualization of amniotic membrane grafts with fluorescein staining during pterygium surgery. METHODS: Pterygium excision surgery using intraoperatively stained cryopreserved amniotic membranes was performed on 346 eyes. A sterile 0.6 mg sodium fluorescein strip was placed directly onto the amniotic membrane in the manufacturer's original packaging, and the stained allograft was then transplanted onto the planned site. Staining intensities, at 3, 5, and 10 minutes of dye immersion, were compared. Immediate postoperative pain rating (scale 0-10), visibility of the fluorescein-stained amniotic membrane graft, and conjunctival autograft and amniotic membrane graft elevation, dehiscence, retraction, or displacement were recorded. The recurrence rate of the study population was compared with that of a previous cohort of 121 patients who underwent pterygium excision with conjunctival autograft without stained amniotic membrane. RESULTS: Direct contact of the fluorescein strip on the amniotic membrane at 3, 5, and 10 minutes showed no differences in subjective staining intensity. Fluorescein-stained amniotic membrane was easily detected on the ocular surface during and 24 hours after pterygium surgery. The average immediate postoperative pain rating was 0.8 ± 1.8. No intraoperative complications or postoperative amniotic membrane graft dehiscence, retraction, or displacement occurred. The recurrence rate using fluorescein-stained amniotic membrane (3 patients, 0.9%, mean follow-up time 31.8 ± 18.6 weeks) did not differ from that of the previous cohort without the stained amniotic membrane (2.5%; χ(1) = 1.837, P = 0.183). CONCLUSIONS: Fluorescein strip staining of the amniotic membrane is a novel and safe intraoperative method to enhance visualization and handling of the graft during and after ocular surgeries.

Cerebral perfusion in insulin resistance and type 2 diabetes.

Cerebral perfusion was evaluated in 87 subjects prospectively enrolled in three study groups-healthy controls (HC), patients with insulin resistance (IR) but not with diabetes, and type 2 diabetes mellitus (T2DM). Participants received a comprehensive 8-hour clinical evaluation and arterial spin labeling magnetic resonance imaging (MRI). In order of decreasing significance, an association was found between cerebral blood flow (CBF) and sex, waist circumference, diastolic blood pressure (BP), end tidal CO2, and verbal fluency score (R(2)=0.27, F=5.89, P<0.001). Mean gray-matter CBF in IR was 4.4 mL/100 g per minute lower than in control subjects (P=0.005), with no hypoperfusion in T2DM (P=0.312). Subjects with IR also showed no CO2 relationship (slope=-0.012) in the normocapnic range, in contrast to a strong relationship in healthy brains (slope=0.800) and intermediate response (slope=0.445) in diabetic patients. Since the majority of T2DM but few IR subjects were aggressively treated with blood glucose, cholesterol, and BP lowering medications, our finding could be attributed to the beneficial effect of these drugs.

Association of obesity-mediated insulin resistance and hypothalamic volumes: possible sex differences.

The hypothalamus is important in hunger and metabolism. Although a lot is known about the basic role of the human hypothalamus, less is known about how the in vivo volume is affected in obesity, particularly among adolescents. Based on pediatric body mass index percentiles, 95 participants were assigned to lean or obese groups. All subjects had medical evaluations, including fasting blood tests, to assess insulin sensitivity and circulating CRP and neurotrophins (NGF and BDNF) and an MRI of the brain. Hypothalamic volumes were measured by a segmentation method combining manual and automated steps. Overall, obese participants had descriptively smaller hypothalamic volumes, although this difference did not reach statistical significance; however, among obese participants, females had significantly smaller hypothalamic volumes than their male counterparts. There was a significant interaction between insulin resistance and sex on hypothalamus volume; obese females with significant insulin resistance have smaller hypothalamic volumes than obese males. Obese adolescents had higher circulating CRP and neurotrophin levels. Furthermore, among obese females, BDNF concentrations were inversely associated with hypothalamus volumes (r = −0.48). Given this negative association between BDNF and hypothalamus volumes among obese insulin-resistant females, elevated neurotrophin levels may suggest an attempt at protective compensation.