The value of contrast sensitivity in diagnosing central serous chorioretinopathy

A 39‐year‐old hyperopic male was referred for laser refractive treatment. In the course of the pre‐operative evaluation he complained of a recent deterioration of vision. The suspicion of unilateral central serous chorioretinopathy (CSCR) was confirmed by contrast sensitivity testing and by ocular fundus examination. Contrast sensitivity (CS) for six spatial frequencies (1, 2, 4, 8, 12 and 16 c/deg) was evaluated using Gabor patches of gratings projected on a high‐resolution display by means of a stimulus generator card. Although VA remained unaltered, the pattern of contrast sensitivity function varied at different stages of CSCR: during the acute stage, performance at all spatial frequencies was depressed, while at two‐month follow up, intermediate and high spatial frequencies were mainly affected. It is concluded that the level of visual deficit in CSCR cannot be evaluated by measuring visual acuity. History and contrast sensitivity can play a central role in setting the correct diagnosis and characterising its stage.     

IMMUNOCHROMATOGRAPHIC TEST: A NEW DIMENSION IN DIAGNOSIS OF PLASMODIUM FALCIPARUM MALARIA

75 patients with clinical features suggestive of malaria were studied to evaluate the efficacy of immunochromatographic test (ICT), which detects histidine rich protein-2 antigen secreted by Plasmodium falciparum (Pfhrp-2), as against direct microscopy. There were 40 cases of P falciparum malaria, 14 cases of P vivax malaria and 21 cases of non-malarial fevers. Direct microscopy could detect 27(67.5%) P falciparum cases but failed to detect 13 cases (32.5%) whereas ICT could detect 35(87.5%) P falciparum cases out of 40 but failed to detect 5(12.5%) cases. All the P vivax cases and non-malarial fever cases were negative for ICT. The sensitivity and specificity of ICT is 87.5% and 100% respectively where as the positive predictive value and the negative predictive value of the test is 100% and 87.5% respectively. It is concluded that ICT test is a good adjunct to blood smear studies in fever cases with neurological and multiorgan dysfunction and in antenatal ladies.Key Words: ICT, P falciparum     

Body Mass Index and Obesity : Tailoring “cut-off” for an Asian Indian Male Population

Background

Obesity/overweight is a recognized risk factor for a host of disorders. The disease risk stratification is commonly based on the Quetelets Index (Body Mass Index- BMI), a surrogate measure of fatness. The currently used BMI cut-offs to classify people as overweight or obese in Armed Forces have been defined in studies on Caucasian populations. However, because of differences in body structure and composition in different ethnic, socioeconomic, cultural and regional groups the correspondence between BMI and body fat content varies between populations. We conducted this pilot study in the Indian Navy to define BMI cut-offs for overweight and obesity using body fat content derived from Skin Fold Thickness as the standard.

Material and Methods

The study was conducted on 121 volunteers from a naval hospital staff in the age range of 18 to 47 years. The mean age, height, weight, BMI, body fat in the study group was 26.73 years (± 5.5098), 168.56 cm (± 6.1034), 65.92 Kg (± 10.2746), 23.17 Kg/m² (± 3.0265) and 19.91% (± 4.831) respectively.

Results

The prevalence of overweight/obesity was 20.66% by BMI and 47.11% by body fat content. Receiver operating characteristic (ROC) curve analysis defined a BMI of 23.85 kg/m² as the cut off for overweight with a sensitivity of 70.2% (95% CI 56.6 – 81.6) and 87.5% specificity (95% CI 76.8-94.4) and a BMI of 24.38 kg/m²with 90% sensitivity (95% CI 68.3-98.5) and 81.2% specificity (95% CI 72.2-88.3) for obesity.

Conclusion

The results of our study suggest lower BMI cut offs for overweight and obesity in Indian populations than those recommended by WHO.Key Words: Body Mass Index, Body fat content, Skin fold thickness     

Epigenetic gene regulation by histone demethylases: emerging role in oncogenesis and inflammation

Histone N‐terminal tails of nucleosomes are the sites of complex regulation of gene expression through post‐translational modifications. Among these modifications, histone methylation had long been associated with permanent gene inactivation until the discovery of Lys‐specific demethylase (LSD1), which is responsible for dynamic gene regulation. There are more than 30 members of the Lys demethylase (KDM) family, and with exception of LSD1 and LSD2, all other KDMs possess the Jumonji C (JmjC) domain exhibiting demethylase activity and require unique cofactors, for example, Fe(II) and α‐ketoglutarate. These cofactors have been targeted when devising KDM inhibitors, which may yield therapeutic benefit. KDMs and their counterpart Lys methyltransferases (KMTs) regulate multiple biological processes, including oncogenesis and inflammation. KDMs’ functional interactions with retinoblastoma (Rb) and E2 factor (E2F) target promoters illustrate their regulatory role in cell cycle progression and oncogenesis. Recent findings also demonstrate the control of inflammation and immune functions by KDMs, such as KDM6B that regulates the pro‐inflammatory gene expression and CD4⁺ T helper (Th) cell lineage determination. This review will highlight the mechanisms by which KDMs and KMTs regulate the target gene expression and how epigenetic mechanisms may be applied to our understanding of oral inflammation.     

In vitro models of cranial neural crest development toward toxicity tests: frog,mouse, and human

During craniofacial development, cranial neural crest (NC)‐derived mesenchymal cells migrate to pharyngeal arches and contribute extensively to neurons, Schwann cells, smooth muscle cells, osteoblasts, chondrocytes, and odontoblasts, forming maxillofacial structures. In vitro models using model organism cells, such as African clawed frog (Xenopus Laevis) and mouse (Mus Musculus), were developed to understand cellular and molecular mechanisms of cranial NC development. Recent studies using human embryonic stem cells (hESCs) and human‐induced pluripotent stem cells (hiPSCs) have enabled the generation of human NC cells (NCCs) in vitro to provide insight into human NC development. Understanding molecular mechanisms underlying craniofacial development will contribute to develop novel embryotoxicity tests and to decrease the incidence of drug‐induced congenital anomalies in the craniofacial region, such as cleft lip or cleft palate. Here, we review culture methods to derive NCCs in vitro from Xenopus presumptive ectoderm (animal caps), mouse embryonic stem cells (mESCs), and human pluripotent stem cells (hPSCs) and discuss how these in vitro models can be used to help clarify the mechanisms underlying craniofacial development and for developing embryotoxicity tests predicting drug‐induced congenital anomalies in the craniofacial region.