Occam's razor... blunted

Occam's razor, [When there are two competing theories making the same prediction, the simpler one is chosen], is a popular method in making clinical diagnosis. This theory gets 'blunted' in our case report, as our immunocompromised patient was found to have multiple non-related aetiologies for a single pathological event.     

Ultrasonic pachymeter: a little different role

Background

Ultrasonic pachymeter, though primarily used in refractive surgery and in glaucoma evaluation, can evaluate and compare the change in corneal thickness following extracapsular cataract extraction (ECCE), small incision cataract surgery (SICS) and phacoemulsification.

Method

Six hundred patients were included in study. Patients were divided into three groups. Group 1 (200 eyes), group 2 (200 eyes) and group 3 (200 eyes) underwent ECCE, SICS, and phacoemulsification, respectively. Corneal thickness was evaluated pre-operatively and postoperatively on day 1, day 2, day 7, day 15, and day 30 by ultrasonic pachymetry.

Results

Mean pre-operative corneal thickness in central, superior, inferior, nasal, and temporal quadrants is 525.35 ± 32.34 μm, 592.23 ± 35.39 μm, 595.66 ± 31.68 μm, 589.29 ± 38.07 μm, and 581.19 ± 42.31 μm, respectively. Postoperatively, a highly significant (P<0.01) increase in central corneal thickness was observed up to day 15 in ECCE, day 7 in SICS whereas it was up to day 2 in phacoemulsification. In superior quadrant, it is up to day 15 in ECCE and SICS whereas it is up to day 7 in phacoemulsification. In inferior quadrant, it was up to day 2 in all three techniques. In temporal quadrant, it is up to day 7 in ECCE and up to day 2 in SICS and phacoemulsification. In nasal quadrant, a highly significant (P<0.01) increase in corneal thickness was observed up to day 7 in ECCE and SICS whereas it was up to day 2 in phacoemulsification.

Conclusion

Normal central corneal thickness is 525.35 ± 32.44 μm. At midperiphery, inferior cornea has maximum corneal thickness followed by superior, temporal, and nasal cornea. Postoperatively, pre-operative value of corneal thickness and visual rehabilitation is achieved earliest in phacoemulsifiaction followed by SICS and ECCE.     

Depressive disorders in school children of suburban India: an epidemiological study

Purpose  

There is a dearth of research on the prevalence of depressive disorders in children from suburban and rural areas in the Indian subcontinent. Therefore, the present study was aimed at assessing the prevalence of depressive disorders and the associated risk factors in the primary and secondary school children in suburban India.     

Initial results on development and application of statistical atlas of femoral cartilage in osteoarthritis to determine sex differences in structure: data from the Osteoarthritis Initiative

Purpose:

To create an average atlas of knee femoral cartilage morphology, to apply the atlas for quantitative assessment of osteoarthritis (OA), and to study localized sex differences.

Materials and Methods:

High‐resolution 3D magnetic resonance imaging (MRI) data of the knee cartilage collected at 3 T as part of the Osteoarthritis Initiative (OAI) were used. An atlas was created based on images from 30 male Caucasian high‐risk subjects with no symptomatic OA at baseline. A female cohort of age‐ and disease‐matched Caucasian subjects was also selected from the OAI database. The Jacobian determinant was calculated from the deformation vector fields that nonlinearly registered each subject to the atlas. Statistical analysis based on the general linear model was used to test for regions of significant differences in the Jacobian values between the two cohorts.

Results:

The average Jacobian was larger in women (1.2 ± 0.078) than in men (1.08 ± 0.097), showing that after global scaling to the male template, the female cartilage was thicker in most regions. Regions showing significant structural differences include the medial weight bearing region, the trochlear (femoral) side of the patellofemoral compartment, and the lateral posterior condyle.

Conclusion:

Sex‐based differences in cartilage structure were localized using tensor based morphometry in a cohort of high‐risk subjects. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Plasma kallikrein mediates retinal vascular dysfunction and induces retinal thickening in diabetic rats

OBJECTIVE

Plasma kallikrein (PK) has been identified in vitreous fluid obtained from individuals with diabetic retinopathy and has been implicated in contributing to retinal vascular dysfunction. In this report, we examined the effects of PK on retinal vascular functions and thickness in diabetic rats.

RESEARCH DESIGN AND METHODS

We investigated the effects of a selective PK inhibitor, ASP-440, and C1 inhibitor (C1-INH), the primary physiological inhibitor of PK, on retinal vascular permeability (RVP) and hemodynamics in rats with streptozotocin-induced diabetes. The effect of intravitreal PK injection on retinal thickness was examined by spectral domain optical coherence tomography.

RESULTS

Systemic continuous administration of ASP-440 for 4 weeks initiated at the time of diabetes onset inhibited RVP by 42% (P = 0.013) and 83% (P < 0.001) at doses of 0.25 and 0.6 mg/kg per day, respectively. Administration of ASP-440 initiated 2 weeks after the onset of diabetes ameliorated both RVP and retinal blood flow abnormalities in diabetic rats measured at 4 weeks’ diabetes duration. Intravitreal injection of C1-INH similarly decreased impaired RVP in rats with 2 weeks’ diabetes duration. Intravitreal injection of PK increased both acute RVP and sustained focal RVP (24 h postinjection) to a greater extent in diabetic rats compared with nondiabetic control rats. Intravitreal injection of PK increased retinal thickness compared with baseline to a greater extent (P = 0.017) in diabetic rats (from 193 ± 10 μm to 223 ± 13 μm) compared with nondiabetic rats (from 182 ± 8 μm to 193 ± 9 μm).

CONCLUSIONS

These results show that PK contributes to retinal vascular dysfunctions in diabetic rats and that the combination of diabetes and intravitreal injection of PK in rats induces retinal thickening.Diabetic macular edema (DME) is a leading cause of vision loss attributed to diabetes. The 14-year incidence of this disease in individuals with type 1 diabetes followed in the Wisconsin Epidemiologic Study of Diabetic Retinopathy was 26% (1), and the progression to clinically significant macular edema was associated with increasing retinopathy severity (2). Although intensive glycemic and blood pressure control can reduce the incidence of DME (3) once this condition develops, the treatment options include laser and vascular endothelial growth factor (VEGF)-targeted therapies, which provide substantial improvement in visual acuity for ~50% of patients with DME (4). Thus, additional treatment options for this disease are needed.DME is associated with a loss of blood-retinal barrier function, leading to increased diffusion of plasma components, thickening of the macula, and impairment in central vision (5,6). In addition to retinal thickening, increased retinal vascular permeability (RVP) alters the biochemical composition of the retinal interstitial fluid and the vitreous. Proteomic studies have begun to characterize the changes in the vitreous protein composition in people with diabetic retinopathy compared with nondiabetic subjects or diabetic subjects without diabetic retinopathy (7). We have previously reported an abundance of vasoactive plasma proteins, including components of the plasma kallikrein (PK)-kinin system (PKKS) in the vitreous of subjects with advanced diabetic retinopathy (7,8). These findings have suggested additional factors besides VEGF that may contribute to the decline in blood-retinal barrier integrity and vascular dysfunction in DME (9,10).Plasma prekallikrein (PPK) is an abundant serine protease zymogen in blood that is converted to its catalytically active form, PK, by factor XIIa (11), contributing to the innate inflammatory response and intrinsic coagulation cascades (12). The mechanisms that lead to the activation of this pathway in vivo include interactions with polyphosphates released from activated platelets and deficiency of C1 inhibitor (C1-INH), the primary physiological inhibitor of the PKKS (13,14). PK-mediated cleavage of high-molecular weight kininogen generates the nonapeptide bradykinin (BK), which activates the BK 2 (B2) receptor. Subsequent cleavage of BK by carboxypeptidases generates des-Arg⁹-BK, which activates the B1 receptor. Both B1 and B2 receptors are expressed by vascular, glial, and neuronal cell types, with the highest levels of retinal expression detected in the ganglion cell layer and inner and outer nuclear layers (15,16). Activation of B1 and B2 receptors causes vasodilation and increases vascular permeability (17–19). Previously, we have demonstrated that intravitreal injection of carbonic anhydrase-1 (CA-1) increased RVP and that this response was blocked by the inhibition of PK and by BK receptor antagonists (8). Recently, we reported that intravitreal injection of PK increased RVP in nondiabetic rats, and systemic administration of a small-molecule PK inhibitor, ASP-440, decreased RVP in rats subjected to angiotensin II (AngII)-induced hypertension (19). In the current study, we investigated the effects of PK on retinal vascular functions and retinal thickness in diabetic rats.     

Early Sexual Risk Among Black and Minority Ethnicity Teenagers: A Mixed Methods Study

PurposeTo determine how ethnic background influences early sexual activity among young adults.MethodsQuantitative data were collected during the Research with East London Adolescents Community Health Survey study, a population-based survey of young adults belonging to white and black and minority ethnic groups and residing in east London in 2001 (n = 2,689) and 2003 (n = 2,675). Qualitative data were obtained from 146 young adults between January and September 2003.ResultsBlack Caribbean, black African, white other, and mixed ethnicity young men were most likely to report high-risk sexual behaviors, that is, sexual debut at the age of ≤13 years, having unprotected sex, and having multiple sexual partners. There were marked variations within groups commonly collapsed as “black” or as “Muslim.” Black Caribbean and black African young adults reported high rates of protective behaviors in addition to risk behaviors. Qualitative data confirmed variations in sexual behavior within ethnic groups. Longitudinally, risk of engaging in two or more high-risk sexual behaviors was predicted by low family support (OR: 2.8, 95% CI: 1.6–4.9), regular smoking (OR: 4.5, 95% CI: 1.7–12.0), and usage of illicit drugs (OR: 2.9, 95% CI: 1.5–5.8), with lower risk predicted by low peer support (OR: .3, 95% CI: .2–.6).ConclusionsYoung adults belonging to black and minority ethnic groups reported a wide variation in sexual risk behaviors. High levels of high-risk behaviors were reported in ethnic groups known to have high rates of sexually transmitted infections. Effective sexual health interventions should be started early and they must focus on sexual debut and partner choices as well as messages regarding safe sex.     

Study of sleep microstructure in patients of migraine without aura

Sleep and Breathing - Although the relationship between sleep and migraine has been widely reported, studies on sleep microstructure are few. The aim was to study and compare microstructural...