The Thoracic Surgery Medical Student Association: Understanding the needs of medical students pursuing cardiothoracic surgery in the United States.

OBJECTIVE: Founded in 2020, the Thoracic Surgery Medical Student Association is the first national organization dedicated to supporting medical students interested in pursuing cardiothoracic surgery. Our inaugural survey aimed to describe their basic characteristics and needs. METHODS: An Institutional Review Board-approved, nonincentivized, anonymous electronic survey was distributed to any medical students enrolled in Liaison Committee on Medical Education-accredited medical schools through social media such as Twitter, national organizations (Association of Women Surgeons, Thoracic Surgery Resident Association), and medical school cardiothoracic surgery interest groups. Their basic characteristics, attitudes, and preferences regarding cardiothoracic surgery were recorded. RESULTS: Of the 167 students from 117 unique schools who completed the survey, 53% identified as White and 57% identified as female. Stages of training were well distributed: 16% first-year medical students, 33% second-year medical students, 16% third-year medical students, 21% fourth-year medical students, and 14% dual degree/research students. Most participants (57%) did not have (32%) or were not aware of having (25%) a thoracic surgery training program at their home institution. The majority (72%) of students reported not having a cardiothoracic surgery interest group at their home institution. The most desired areas of cardiothoracic were networking (31%) and mentorship (28%). CONCLUSIONS: There is a significant need to directly engage medical students who are interested in cardiothoracic surgery considering limited exposure at home institutions through a lack of cardiothoracic surgery interest groups and cardiothoracic residency programs. The Thoracic Surgery Medical Student Association is poised to address these areas with directed networking by connecting cardiothoracic surgery faculty and residents from other institutions with medical students interested in pursuing cardiothoracic surgery.

Attrition rates in integrated vascular and cardiothoracic surgery residency and fellowship programs.

BACKGROUND: Attrition in surgical programs remains a significant problem resulting in trainee dissatisfaction and wasted time and educational dollars. Attrition rates in general surgery training programs approximate 5% per year (30% cumulative). Attrition rates in cardiovascular surgery training for the traditional vascular surgery fellowship (VSF), the vascular surgery residency (VSR), and the corresponding programs in cardiothoracic surgery have yet to be described, although they are assumed to be similar to those associated with general surgery training. METHODS: A retrospective review of the Association of American Medical Colleges Annual Physician Specialty Data Book was performed. Data from consecutive academic years 2007-2008 to 2013-2014 were analyzed. The number of total residents, the number who did not complete their training, and those who successfully completed the program were recorded. Attrition rates were then calculated for VSF, VSR, general surgery residency (GSR), cardiothoracic surgery fellowship (CTF), and cardiothoracic surgery integrated residency (CTR). RESULTS: Annually, between 2007-2008 and 2013-2014, there were zero to two vascular surgery residents who failed to complete the program (0%-5.9%). In the last 4 years of the study, whereas the absolute number of residents who failed to complete the program remained constant at 1 or 2 per year, the attrition rate decreased to 1 of 171 trainees (0.6%) in 2013-2014 as the total number of programs (and numbers of vascular surgery residents) significantly increased. During the same 7-year period, the number of vascular surgery fellows who did not complete their training ranged from one to six annually (0.4%-2.5%). Compared with the VSF, the VSR data show a relatively low and constant rate of attrition. In contrast, the number of general surgery residents who did not complete their program during the study period varied from 255 to 388 residents annually (3.3%-5.2%). During its first 3 years of inception, the CTR program had an attrition rate of 0%, and it was not until 2012-2013 that trainees failed to complete the program, resulting in an annual attrition rate of 1.2% to 3.2% from that point on. The annual attrition rate of CTF training programs ranged from 7 to 15 fellows (2.9%-6.8%) during the study period. CONCLUSIONS: The inception of VSR and CTR programs dramatically changed the paradigms for training in these highly specialized surgical fields. Comparisons of attrition rates between these two programs and the traditional VSF and CTR as well as GSR suggests lesser rates of attrition in the integrated programs. These data may prove reassuring to VSR and CTR program directors, whose significantly smaller programs are more vulnerable to the loss of even a single trainee than general surgery training programs are. In addition, the VSF program has stable and lower attrition rates compared with the CTF and GSR programs.

Effect of ghost pepper on cell proliferation, apoptosis, senescence and global proteomic profile in human renal adenocarcinoma cells.

Chili peppers are an important constituent of many foods and contain medicinally valuable compounds, such as capsaicin and dihydrocapsaicin. As various dietary botanicals have anticancer properties, this study was aimed to examine the effect of Ghost pepper (Bhut Jolokia), one of the hottest chili peppers in the world, on cell proliferation, apoptosis, senescence and the global proteomic profile in human renal cell adenocarcinoma in vitro. 769-P human renal adenocarcinoma cells were cultured on RPMI-1640 media supplemented with fetal bovine serum (10%) and antibiotic-antimycotic solution (1%). Treatment stock solutions were prepared in ethanol. Cell proliferation was tested with phenol red-free media with capsaicin (0-400 µM), dihydrocapsaicin (0-400 µM), capsaicin + dihydrocapsaicin (5:1), and dry Ghost peppers (0-3 g L-1) for 24, 48 and 72 h. Polycaspase and senescence associated-beta-galactosidase (SA-beta-gal) activities were tested with capsaicin (400 µM), dihydrocapsaicin (400 µM), capsaicin (400 µM) + dihydrocapsaicin (80 µM), and ghost pepper (3 g L-1) treatments. Global proteomic profile of cells in control and ghost pepper treatment (3 g L-1) was analyzed after 6 h by a shotgun proteomic approach using tandem mass spectrometry. At 24 h after treatment (24 HAT), relative to control, cell proportion with capsaicin (400 µM), dihydrocapsaicin (400 µM), capsaicin (400 µM) + dihydrocapsaicin (80 µM), and ghost pepper (3 g L-1) treatments was reduced to 36%, 18%, 33% and 20%, respectively, and further reduced at 48 and 72 HAT. All treatments triggered an early polycaspase response. SA-beta-gal activity was normal or suppressed with all treatments. About 68,220 protein isoforms were identified by shotgun proteomic approach. Among these, about 8.2% were significantly affected by ghost pepper. Ghost pepper regulated various proteins involved in intrinsic and extrinsic apoptotic pathways, Ras, Rb/E2F, p53, TGF-beta, WNT-beta catenin, and calcium induced cell death pathways. Ghost pepper also induced changes in proteins related to methylation, acetylation, genome stability, cell cycle check points, carbohydrate, protein and other metabolism and cellular mechanisms. Ghost pepper exhibited antiproliferation activity by inducing apoptosis through a complex network of proteins in human renal cell adenocarcinoma in vitro.

Nonspecific block of voltage-gated potassium channels has greater effect on distal schaffer collaterals than proximal schaffer collaterals during periods of high activity.

Previous studies established different responses between proximal and distal portions of Schaffer collateral axons during high-frequency and burst stimulation, with distal axons demonstrating biphasic changes in excitability (hyperexcitability followed by depression), but proximal axons showing only monophasic depression. Voltage-dependent potassium (KV) channels are important determinants of axonal excitability, and block of KV channels can promote axon hyperexcitability. We therefore hypothesized that block of KV channels should lead to biphasic response changes in proximal Schaffer collaterals, like those seen in distal Schaffer collaterals. To test this hypothesis, we made extracellular recordings of distal Schaffer collateral responses in stratum radiatum of hippocampal area CA1 and proximal Schaffer collateral responses in stratum pyramidale of area CA3 during high-frequency stimulation (HFS) at 100 Hz and burst stimulation at 200 msec intervals (5 Hz or theta frequency). We then applied a nonselective KV channel blocker, tetraethlylammonium (TEA, 10 mmol/L) or 4-aminopyridine (4-AP, 100 µmol/L), and assessed effects on Schaffer collateral responses. Surprisingly, block of KV channels had little or no effect on proximal Schaffer collateral responses during high-frequency or burst stimulation. In contrast, KV channel blockade caused more rapid depression of distal Schaffer collateral responses during both high-frequency and burst stimulation. These findings indicate that KV channels are important for maintaining distal, but not proximal, Schaffer collateral excitability during period of sustained high activity. Differential sensitivity of distal versus proximal Schaffer collaterals to KV channel block may reflect differences in channel density, diversity, or subcellular localization.

A genome-wide scan of selective sweeps and association mapping of fruit traits using microsatellite markers in watermelon.

Our genetic diversity study uses microsatellites of known map position to estimate genome level population structure and linkage disequilibrium, and to identify genomic regions that have undergone selection during watermelon domestication and improvement. Thirty regions that showed evidence of selective sweep were scanned for the presence of candidate genes using the watermelon genome browser (www.icugi.org). We localized selective sweeps in intergenic regions, close to the promoters, and within the exons and introns of various genes. This study provided an evidence of convergent evolution for the presence of diverse ecotypes with special reference to American and European ecotypes. Our search for location of linked markers in the whole-genome draft sequence revealed that BVWS00358, a GA repeat microsatellite, is the GAGA type transcription factor located in the 5' untranslated regions of a structure and insertion element that expresses a Cys2His2 Zinc finger motif, with presumed biological processes related to chitin response and transcriptional regulation. In addition, BVWS01708, an ATT repeat microsatellite, located in the promoter of a DTW domain-containing protein (Cla002761); and 2 other simple sequence repeats that association mapping link to fruit length and rind thickness.

High-resolution genetic map for understanding the effect of genome-wide recombination rate on nucleotide diversity in watermelon.

We used genotyping by sequencing to identify a set of 10,480 single nucleotide polymorphism (SNP) markers for constructing a high-resolution genetic map of 1096 cM for watermelon. We assessed the genome-wide variation in recombination rate (GWRR) across the map and found an association between GWRR and genome-wide nucleotide diversity. Collinearity between the map and the genome-wide reference sequence for watermelon was studied to identify inconsistency and chromosome rearrangements. We assessed genome-wide nucleotide diversity, linkage disequilibrium (LD), and selective sweep for wild, semi-wild, and domesticated accessions of Citrullus lanatus var. lanatus to track signals of domestication. Principal component analysis combined with chromosome-wide phylogenetic study based on 1563 SNPs obtained after LD pruning with minor allele frequency of 0.05 resolved the differences between semi-wild and wild accessions as well as relationships among worldwide sweet watermelon. Population structure analysis revealed predominant ancestries for wild, semi-wild, and domesticated watermelons as well as admixture of various ancestries that were important for domestication. Sliding window analysis of Tajima's D across various chromosomes was used to resolve selective sweep. LD decay was estimated for various chromosomes. We identified a strong selective sweep on chromosome 3 consisting of important genes that might have had a role in sweet watermelon domestication.

Single nucleotide polymorphisms generated by genotyping by sequencing to characterize genome-wide diversity, linkage disequilibrium, and selective sweeps in cultivated watermelon.

BACKGROUND: A large single nucleotide polymorphism (SNP) dataset was used to analyze genome-wide diversity in a diverse collection of watermelon cultivars representing globally cultivated, watermelon genetic diversity. The marker density required for conducting successful association mapping depends on the extent of linkage disequilibrium (LD) within a population. Use of genotyping by sequencing reveals large numbers of SNPs that in turn generate opportunities in genome-wide association mapping and marker-assisted selection, even in crops such as watermelon for which few genomic resources are available. In this paper, we used genome-wide genetic diversity to study LD, selective sweeps, and pairwise FST distributions among worldwide cultivated watermelons to track signals of domestication. RESULTS: We examined 183 Citrullus lanatus var. lanatus accessions representing domesticated watermelon and generated a set of 11,485 SNP markers using genotyping by sequencing. With a diverse panel of worldwide cultivated watermelons, we identified a set of 5,254 SNPs with a minor allele frequency of ≥ 0.05, distributed across the genome. All ancestries were traced to Africa and an admixture of various ancestries constituted secondary gene pools across various continents. A sliding window analysis using pairwise FST values was used to resolve selective sweeps. We identified strong selection on chromosomes 3 and 9 that might have contributed to the domestication process. Pairwise analysis of adjacent SNPs within a chromosome as well as within a haplotype allowed us to estimate genome-wide LD decay. LD was also detected within individual genes on various chromosomes. Principal component and ancestry analyses were used to account for population structure in a genome-wide association study. We further mapped important genes for soluble solid content using a mixed linear model. CONCLUSIONS: Information concerning the SNP resources, population structure, and LD developed in this study will help in identifying agronomically important candidate genes from the genomic regions underlying selection and for mapping quantitative trait loci using a genome-wide association study in sweet watermelon.