Visual Factors in the Avoidance of Front-To-Rear-End Highway Collisions

Two visual factors in the avoidance of front-to-rear-end collisions are (a) judging time to collision so as to control braking optimally on a moment-to-moment basis, and/or (b) judging one's heading relative to the lead car so as to steer appropriately. It is known that time to contact equals θ/(dθ/dt) and it is also known that the eye is sensitive to θ and, separately, (dθ/dt) (θ is the angular size and (dθ/dt) is the rate of increase of angular size). But whether the eye is sensitive to the ratio (θ/(dθ/dt) and, if so, whether drivers use this information are further questions. We report here that the human visual system does contain neurons sensitive to the ratio θ/(dθ/dt) rather independently of θ and (dθ/dt). It is important that the driver looks directly at the lead vehicle: sensitivity to (dθ/dt) falls off steeply in peripheral view. But, over a wide range, sensitivity to (dθ/dt) is independent of contrast. In addition to the classical disparity-driven system for binocular depth perception, there is a separate binocular system for motion in depth. Precise judgements (0.2 deg) of heading are supported by this stereomotion system, but on the other hand about 20% of the population have stereomotion “blind spots” (i.e. field defects). Monocularly-available informations can also support precise judgements of heading, and field defects seem to be rare. Field studies on flight simulators and telemetry-tracked jet aircraft showed that laboratory measures of sensitivity to (dθ/dt) and to the rate of expansion of the optical flow field predicted intersubject differences in performance on flying tasks that were closely related to the rear-end collision situation.

Application and interpretation of genome-wide association (GWA) studies for informing pharmacogenomic research - examples from the field of age-related macular degeneration

Genome-wide association (GWA) studies apply broad DNA scans on hundreds-of-thousands of common sequence variants in thousands of people for the purpose of mapping trait- or disease-related loci. We provide examples of ligand- and target-based studies from the field of age-related macular degeneration (AMD) to demonstrate the value of the GWA approach in confirmatory and exploratory pharmacogenomics research. Complementing this genomic analysis, we used a simple biochemical retinal pigment epithelium (RPE) oxidative, apoptotic high throughput screening (HTS) assay to identify compounds. This ligand-to-targetto DNA sequence variant-to disease approach provided guidance on rational design of preclinical studies and identified associations between: 1) valproic acid and advanced AMD-associated genes with the capacity to alter GABA-succinate signaling (ALDH5A1, CACNA1C, SUCLA2, and GABBR2) and chromatin remodeling (HDAC9); and 2) Ropinirole and a geographic atrophy-associated gene (DRD3) with the capacity to alter systems involved in cAMP-PKA signaling. In both applications of our method, the breadth of GWA findings allowed efficient expansion of results to identify enriched pathways and additional ligands capable of targeting pathway constituents. A disease associated SNP-to gene-to target-to ligand approach provided guidance to inform preventive and therapeutic preclinical studies investigating roles of targets in: 1) PPAR-RXR transcription complex constituents for neovascular AMD; and 2) the stress activated MAPK signaling cascade constituents for advanced AMD. Our conclusion is that publically available data from GWA studies can be used successfully with open-access genomics, proteomics, structural chemistry, and pharmacogenomics databases in an efficient, rational approach to streamline the processes of planning and implementation for confirmatory and exploratory pre-clinical studies of preventive or therapeutic pharmacologic treatments for complex diseases.

Spinal Tuberculosis with Paraplegia in Pregnancy

Spinal tuberculosis leading to paraplegia is uncommon in pregnancy and is a diagnostic and therapeutic challenge. We report a case of tubercular paraplegia presenting at 35 weeks of gestation. She was managed with Anti-tubercular drugs and did not require surgical intervention. Her neurological status improved and she was allowed to go in labour. She delivered a healthy term infant by cesarean. At three months follow-up, both mother and child are doing well.

A multicenter study of primary graft failure after infant heart transplantation: impact of extracorporeal membrane oxygenation on outcomes

Primary graft failure is the major cause of mortality in infant HTx. The aim of this study was to characterize the indication and outcomes of infants requiring ECMO support due to primary graft failure after HTx. We performed a retrospective review of all infants (<1 yr) who underwent Htx from three institutions. From 1999 to 2008, 92 infants (<1 yr) received Htx. Sixteen children (17%) required ECMO after Htx due to low cardiac output syndrome. Eleven (69%) infants were successfully weaned off ECMO, and 9 (56%) infants were discharged with a mean follow-up of 2.3 ± 2.5 yr. Mean duration of ECMO in survivors was 5.4 days (2-7 days) compared with eight days (2-10 days) in non-survivors (p = NS). The five-yr survival rate for all patients was 75%; however, the five-yr survival rate was 40% in the ECMO cohort vs. 80% in the non-ECMO cohort (p = 0.0001). Graft function within one month post-Htx was similar and normal between ECMO and non-ECMO groups (shortening fraction = 42 ± 3 vs. 40 ± 2, p = NS). For infants, ECMO support for primary graft failure had a lower short-term and long-term survival rate vs. non-ECMO patients. Duration of ECMO did not adversely impact graft function and is an acceptable therapy for infants after HTx for low cardiac output syndrome.

Migration and access to maternal healthcare: determinants of adequate antenatal care and institutional delivery among socio-economically disadvantaged migrants in Delhi, India

OBJECTIVE

To identify the determinants of adequate antenatal care (ANC) utilisation and institutional deliveries among socio-economically disadvantaged migrants living in Delhi, India.

METHODS

In a cross-sectional survey, 809 rural-urban migrant mothers with a child aged below 2 years were interviewed with a pretested questionnaire. Data on receiving antenatal, delivery and post-natal services, migration history and other social, demographic and income were collected.

RESULTS

Recent migrants used the services significantly less than settled migrants. ANC was adequate only among 37% (35% of recent migrant women and 39% of settled migrants). Multinomial regression revealed that being a recent migrant, multiparous, illiterate and married to an unskilled worker were significant risk factors for receiving inadequate ANC. Around 53% of deliveries took place at home. ANC seeking has a strong influence on place of delivery: 70% of births to women who received inadequate ANC were at home. Women who are educated, had their first delivery after the age of 20 years and received adequate ANC were more likely to deliver their child in hospital. Post-natal care is grossly neglected among these groups.

CONCLUSION

Migrant women, particularly recent migrants, are at the risk of not receiving adequate maternal healthcare. Because migration is a continuing phenomenon, measures to mitigate disadvantage due to migration need to be taken in the healthcare system.

An unusual cause of reversible axonal neuropathy and hypertension in a 10-year-old girl

A 10-year-old girl, who was referred with refractory epilepsy, had 1.5 years of episodic abnormal behavior. On examination, she also had hypertension and peripheral neuropathy. Hypoglycemia with correspondingly high insulin levels was documented during a confusional episode. MRI of the abdomen revealed an islet cell tumor in the body of the pancreas. One year after tumor excision, both the neuropathy and hypertension showed remarkable improvement. A final diagnosis of insulinoma with hypoglycemic axonal neuropathy and hypertension (reversed with tumor excision) was made. Insulinoma is the commonest cause of hyperinsulinemic hypoglycemia in adults, but is rare in childhood. To our knowledge, distal symmetrical motor-sensory axonal neuropathy has been described in only 40 patients, and hypertension has not been reported with insulinoma.

Recurrent floods and prevalence of diarrhea among under five children: observations from Bahraich district, Uttar Pradesh, India

Background

Diarrhea is an important problem among the under-five children in India.

Objective

The paper examines long-term impacts of recurrent floods on diarrhea among under-five children in Uttar Pradesh, India.

Design

A two stage stratified cluster survey was conducted in flood affected (exposed) and non-flood affected areas (unexposed).

Results

The long-term impact of the floods was not clearly marked in the overall prevalence of diarrhea with the exposed group having prevalence of 55.1% as against 56.2% in the unexposed group of children under five. Economic condition of the household is associated with the prevalence of diarrhea in both exposed and unexposed strata. Anemia was found to be a significant risk factor for diarrhea among children in both the flood exposed and non-flood exposed populations. The recurrent floods did not have any significant effect on the prevalence of diarrhea in relation to gender, religion, caste, and household size.

Conclusions

The study indicates that the long-term impacts of floods are very differently manifested than the immediate impacts.

Detection of aberrant drainage after sentinel lymph node mapping and its impact on staging and change of operation in colon cancer

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Background: Sentinel lymph node mapping in colon cancer leads to the detection of micrometastasis in 15- 20% of patients leading to upstaging to stage III disease.

Methods: Between 1996-2010, patients diagnosed with colon cancer were enrolled in our study and underwent SLNM at the tim of surgery plus standard oncological resection including regional LN resection. After initial years of experience, exact locations of the SLNs were mapped in relation to the primary tumor. Aberrant drainage was observed when a SLN was detected outside the standard lymph node basin. The primary objective of this analysis is to identify the frequency of detection of such aberrant drainage and the rates of positive aberrant SLNs leading to change of operation and staging.

Results: Between 1996-2010, 304 patients were included in the study. The overall success rates of SLNM was 99.7%. The average number of resected LNs was 15.4. SLNM had a sensitivity, negative predictive value, accuracy and false negative rates of 85.3%, 91.7%, 94.4% and 14.6% respectively. Micrometastatic disease was detected in 15.1% of patients with node positive disease. Since 2001, 150 patients were evaluated for the presence of aberrant drainage and potential change of planned surgery. In 27 patients (18%), extended surgery was performed due to aberrant drainage. The nodal positivity in these 27 patients was 59.5%, compared to 46% in the whole group. The average number of lymph nodes in this group was 16 and the average number of SLNs was 4.3. The most common location of the primary tumor was the right colon in 55.6% of patients with aberrant drainage. In 13 patients (8.7% of case), change of operation led to the detection of positive SLNs leading to upstaging to stage IIIA/B diseases. All of these 13 patients had T3 or T4 disease. All node positive patients underwent adjuvant chemotherapy.

Conclusions: SLNM in colon cancer is highly successful, sensitive and overall accurate staging procedure. It leads to detection of SLNs outside the regional lymphatic basin and change of surgery in 18% of patients. This results in higher nodal positivity and significant change of planned surgery in 8.7% of cases.

No significant financial relationships to disclose.

Study of relationship between facial index and gestational age in normal newborns

Anthropometric dimensions are the basis of evaluation of health of newborns. Results of cephalometric studies can be used in forensic medicine, plastic surgery, pediatrics, oral surgery, dentistry, otolaryngology and syndromology. Three hundred sixty appropriate for gestational age newborns belonging to the region in and around Patiala were the subjects of the present study. The gestational age varied from 29 to 41 weeks. Face length and face width were measured and facial index was calculated. The overall mean face length and mean face width were 5.17 cm and 6.42 cm respectively. Facial index ranged from 79.3 - 81.4% with mean facial index being 80.5%. Facial index increased with increasing gestational age. Gestational age has negative correlation with face length and face width but positively significant correlation was observed between gestational age and facial index. Facial length and facial width were jointly determined. All inter-relationships improved remarkably when determined for gestational age groups. These findings have significant implication as gestational age linearly influenced facial index. In addition they provide database from 29th to 41st week of gestation and can be used as baseline for further anthropometric studies to specify the role of heredity and environment.

Therapeutic potential of valproic acid for retinitis pigmentosa

BACKGROUND/AIM

To examine the efficacy and safety of valproic acid (VPA) in patients with retinitis pigmentosa (RP).

METHODS

Thirteen eyes were examined before and after brief treatment (average 4 months) with VPA. Visual fields (VF) for each eye were defined using digitised Goldmann Kinetic Perimetry tracings. VF areas were log-transformed and VF loss/gain relative to baseline was calculated. Visual acuity was measured using a Snellen chart at a distance of 20&emsp14;feet (6.1 m). Values were converted to the logarithm of the minimum angle of resolution (logMAR) score.

RESULTS

Nine eyes had improved VF with treatment, two eyes had decreased VF and two eyes experienced no change, with an overall average increase of 11%. Assuming typical loss in VF area without treatment, this increase in VF was statistically significant (p<0.02). An average decrease (0.172) in the logMAR scores was seen in these 13 eyes, which translates to a positive change in Snellen score of approximately 20/47 to 20/32, which was significant (p<0.02) assuming no loss in acuity without treatment. Side effects were mild and well tolerated.

CONCLUSION

Treatment with VPA is suggestive of a therapeutic benefit to patients with RP. A placebo-controlled clinical trial will be necessary to assess the efficacy and safety of VPA for RP rigorously.