Conjunctival Melanoma in Asian Indians: A Study of 42 Patients

Purpose: To describe the clinical features, treatment, and outcomes of conjunctival melanoma in Asian Indians.

Methods: Retrospective study of 42 patients.

Results: The mean age at presentation of conjunctival melanoma was 43 years (median, 45 years; range, 9–78 years). There were 20 (48%) males and 22 (52%) females. Nineteen patients (45%) had a known history of a preexisting pigmented conjunctival lesion. Bulbar conjunctiva (n = 28; 67%) was the most common tumor epicenter, and medial ocular surface quadrant (n = 15; 36%) was more commonly involved. The mean tumor basal diameter was 12 mm (median, 10 mm; range, 4–30 mm), and the mean tumor thickness was 4 mm (median, 2 mm; range, 1–30 mm). Majority of the patients had a pigmented tumor (n = 33; 79%). The tumors arose de novo (n = 17, 41%) or were associated with conjunctival nevus (n = 9; 21%) or primary acquired melanosis (n = 16, 38%). Wide excisional biopsy, adjunctive cryotherapy, and amniotic membrane grafting were performed in 27 (71%) patients, 11 (29%) underwent orbital exenteration, and 4 were lost to follow-up prior to definitive treatment. Over a mean follow-up period of 24 months (median, 9 months; range, <1 to 136 months), four (11%) patients had tumor recurrence, seven (18%) had locoregional lymph node metastasis, and four (11%) developed systemic metastasis and died due to metastatic disease.

Conclusion: Conjunctival melanoma predominantly occurs in middle-aged Asian Indians and is associated with a high rate of systemic metastasis and death.     

Can neuroimaging help aphasia researchers? Addressing generalizability,variability, and interpretability

Neuroimaging studies of individuals with brain damage seek to link brain structure and activity to cognitive impairments, spontaneous recovery, or treatment outcomes. To date, such studies have relied on the critical assumption that a given anatomical landmark corresponds to the same functional unit(s) across individuals. However, this assumption is fallacious even across neurologically healthy individuals. Here, we discuss the severe implications of this issue, and argue for an approach that circumvents it, whereby: (i) functional brain regions are defined separately for each subject using fMRI, allowing for inter-individual variability in their precise location; (ii) the response profile of these subject-specific regions are characterized using various other tasks; and (iii) the results are averaged across individuals, guaranteeing generalizabliity. This method harnesses the complementary strengths of single-case studies and group studies, and it eliminates the need for post hoc “reverse inference” from anatomical landmarks back to cognitive operations, thus improving data interpretability.     

Retinoblastoma: Achieving new standards with methods of chemotherapy

The management of retinoblastoma (RB) has dramatically changed over the past two decades from previous radiotherapy methods to current chemotherapy strategies. RB is a remarkably chemotherapy-sensitive tumor. Chemotherapy is currently used as a first-line approach for children with this malignancy and can be delivered by intravenous, intra-arterial, periocular, and intravitreal routes. The choice of route for chemotherapy administration depends upon the tumor laterality and tumor staging. Intravenous chemotherapy (IVC) is used most often in bilateral cases, orbital RB, and as an adjuvant treatment in high-risk RB. Intra-arterial chemotherapy (IAC) is used in cases with group C or D RB and selected cases of group E tumor. Periocular chemotherapy is used as an adjunct treatment in eyes with group D and E RB and those with persistent/recurrent vitreous seeds. Intravitreal chemotherapy is reserved for eyes with persistent/recurrent vitreous seeds. In this review, we describe the various forms of chemotherapy used in the management of RB. A database search was performed on PubMed, using the terms “RB,” and “treatment,” “chemotherapy,” “systemic chemotherapy,” “IVC,” “IAC,” “periocular chemotherapy,” or “intravitreal chemotherapy.” Relevant English language articles were extracted, reviewed, and referenced appropriately.     

Epibulbar schwannoma in a 12-year-old boy: A case report and review of literature

Schwannomas are benign, encapsulated, primary neurilemmal tumors composed of proliferating Schwann cells. Schwannomas are commonly seen in the orbit, but are rare on the epibulbar surface. Herein, we report a case of a 12-year-old boy who presented to us with a slow-growing painless subconjunctival mass in the left eye. There was no intraocular extension of the mass and intra-operatively, the mass could be clearly delineated and was excised off the underlying sclera. Histopathological examination of the mass showed typical features of schwannoma and immunohistochemistry helped to confirm the diagnosis. There was no recurrence of the lesion observed at follow-up 26 months after surgery. Here, we describe this uncommon tumor and review the available literature. Although rare, an epibulbar schwannoma should be considered in the differential diagnosis of an amelanotic, painless subconjunctival nodular mass. Excision of the lesion is the recommended treatment.     

Late-Onset Suicide: A Dementia Prodrome?

ObjectivesThis study examined whether late-onset (versus early-onset) suicidal behavior is associated with worse cognition.MethodsParticipants included 278 adults aged 50+ years (56 nonpsychiatric comparison group; 67 nonsuicidal depressed older adults; 63 depressed suicide ideators; and 44 late-onset (55+ years) and 48 early-onset suicide attempters (<55 years). Using a case-control design, this study examined group differences in global cognition, episodic memory, information processing speed, and executive functioning, assessed using the Repeatable Battery of Neuropsychological Status and the Trail Making Test from the Delis-Kaplan Executive Function System. Linear regression was used for data analyses.ResultsBoth attempter groups displayed worse executive functioning than nonsuicidal depressed older adults. Late-onset attempters additionally displayed poorer global cognition and processing speed than nonsuicidal depressed older adults and poorer memory than early-onset attempters.ConclusionsLate-onset suicidal behavior is associated with worse performance in a broad range of cognitive domains, possibly reflective of a dementia prodrome.     

Understanding the effects of shape,material and location of incorporation of metal nanoparticles on the performance of plasmonic organic solar cells

Truncated octahedral gold (Au) nanoparticles (NPs), Au nanocubes (NCs)-, and silver (Ag) NCs are used to study the effect of NPs shape, material and incorporation location on the performance of poly(3-hexylthiophene):[6,6]-phenyl-C₇₁-butyric acid methyl ester (P3HT:PC₇₁BM) based inverted bulk heterojunction (BHJ) organic solar cells (OSCs). Plasmonic OSCs (POSCs) with NPs incorporated as an interfacial layer between zinc oxide (ZnO) and active layer showed highest power conversion efficiency (PCE) and short circuit current density (J_sc) values for all kind of shapes and material compared to POSCs with NPs blended into the active layer. Near-field enhancement as well as enhanced forward scattering cross section is attributed for POSC performance improvement. Among the NPs with two shapes, POSCs with truncated octahedral Au NPs exceeded the photovoltaic performance compared to those of POSCs with Au and Ag NCs. Large number of antennas in truncated octahedral Au NPs compared to NC is reasoned to be the cause for this improvement. Even though Ag has better localised surface plasmon resoanance (LSPR) properties compared to Au, the POSCs with Ag NCs showed lower J_sc value and is due to reduced number of photons at the blue shifted LSPR wavelength of Ag NCs. The improvement in J_sc values of POSCs is confirmed by enhancement in absorption, external quantum efficiency (EQE), exciton generation and exciton dissociation probability measurements and is due to improved LSPR coupling of the NPs with the active layer. The surface enhanced Raman scattering (SERS) and photoluminescence (PL) studies confirm the absorption enhancement in the active layer by NP LSPR coupling and further confirm the enhancement in the photovoltaic performance of POSCs.

Enhanced performance in organic solar cells by incorporating non-spherical metal nanoparticles.     

Pharmacokinetics of First-Line Antituberculosis Drugs in HIV-Infected Children with Tuberculosis Treated with Intermittent Regimens in India

The objective of this report was to study the pharmacokinetics of rifampin (RMP), isoniazid (INH), and pyrazinamide (PZA) in HIV-infected children with tuberculosis (TB) treated with a thrice-weekly anti-TB regimen in the government program in India. Seventy-seven HIV-infected children with TB aged 1 to 15 years from six hospitals in India were recruited. During the intensive phase of TB treatment with directly observed administration of the drugs, a complete pharmacokinetic study was performed. Drug concentrations were measured by high-performance liquid chromatography. A multivariable regression analysis was done to explore the factors impacting drug levels and treatment outcomes. The proportions of children with subnormal peak concentrations (C_max) of RMP, INH, and PZA were 97%, 28%, and 33%, respectively. Children less than 5 years old had a lower median C_max and lower exposure (area under the time-concentration curve from 0 to 8 h [AUC_0–8]) of INH (C_max, 2.5 versus 5.1 μg/ml, respectively [P = 0.016]; AUC_0–8, 11.1 versus 22.0 μg/ml · h, respectively [P = 0.047[) and PZA (C_max, 34.1 versus 42.3 μg/ml, respectively [P = 0.055]; AUC_0–8, 177.9 versus 221.7 μg/ml · h, respectively [P = 0.05]) than those more than 5 years old. In children with unfavorable versus favorable outcomes, the median C_max of RMP (1.0 versus 2.8 μg/ml, respectively; P = 0.002) and PZA (31.9 versus 44.4 μg/ml, respectively; P = 0.045) were significantly lower. Among all factors studied, the PZA C_max influenced TB treatment outcome (P = 0.011; adjusted odds ratio, 1.094; 95% confidence interval, 1.021 to 1.173). A high proportion of children with HIV and TB had a subnormal RMP C_max. The PZA C_max significantly influenced treatment outcome. These findings have important clinical implications and emphasize that drug doses in HIV-infected children with TB have to be optimized.     

Increase in minimum inhibitory concentration to quinolones and ceftriaxone in salmonellae causing enteric fever

Multidrug resistance among Salmonella typhi is well known. Reports of treatment failure in enteric fever with Ciprofloxacin made us undertake this study to determine the antibiotic susceptibility pattern of S. typhi and S. paratyphi A isolated from typhoid bacteremia cases, by disc diffusion and MIC by broth dilution method. A total of 50 strains were tested, 48 of Salmonella typhi and 2 of S. paratyphi A. The disc diffusion method was done using ampicillin, chloramphenicol, cotrimoxazole, tetracycline, ciprofloxacin, ofloxacin, cefuroxime and ceftriaxone as antibiotics. The MIC was performed using ciproloxacin, ofloxacin and ceftriaxone based on standard procedure. ACCOT resistance as determined by disc diffusion method was seen in 68% of isolates. All the strains remained susceptible to flouroquinolones cephalosporins and aminoglycosides. The MIC of ciprofloxacin, ofloxacin and ceftriaxone were in the recommended range of susceptibility as given by NCCLS, 14 (28%) strains had MIC of ciprofloxacin greater than 0.5 ug/ml with 4 strains having an MIC of 1.56 ug/ml; 25 (50%) strains had MIC of ofloxacin greater than 0.5 ug/ml and 20 (40%) strains had MIC of ceftriaxone greater than 0.5 ug/ml. The high levels of MIC of ciprofloxacin may account for treatment failure cases. The rising levels of MIC of ofloxacin and ceftriaxone in S. typhi and S. paratyphi is also of concern. We document here the emergence of high levels of MIC not only to ciprofloxacin, but also ofloxacin and ceftriaxone in S. typhi and S. paratyphi A. We recommend that MIC levels of ofloxacin and ceftriaxone should be monitored along with ciprofloxacin in treatment failure cases of enteric fever.