Gloria R. Sue

Arginine residues at internal positions in a protein are always charged.

Many functionally essential ionizable groups are buried in the hydrophobic interior of proteins. A systematic study of Lys, Asp, and Glu residues at 25 internal positions in staphylococcal nuclease showed that their pKa values can be highly anomalous, some shifted by as many as 5.7 pH units relative to normal pKa values in water. Here we show that, in contrast, Arg residues at the same internal positions exhibit no detectable shifts in pKa; they are all charged at pH ≤ 10. Twenty-three of these 25 variants with Arg are folded at both pH 7 and 10. The mean decrease in thermodynamic stability from substitution with Arg was 6.2 kcal/mol at this pH, comparable to that for substitution with Lys, Asp, or Glu at pH 7. The physical basis behind the remarkable ability of Arg residues to remain protonated in environments otherwise incompatible with charges is suggested by crystal structures of three variants showing how the guanidinium moiety of the Arg side chain is effectively neutralized through multiple hydrogen bonds to protein polar atoms and to site-bound water molecules. The length of the Arg side chain, and slight deformations of the protein, facilitate placement of the guanidinium moieties near polar groups or bulk water. This unique capacity of Arg side chains to retain their charge in dehydrated environments likely contributes toward the important functional roles of internal Arg residues in situations where a charge is needed in the interior of a protein, in a lipid bilayer, or in similarly hydrophobic environments.

Effect of Program Type on the Training Experiences of 248 University, Community, and US Military-Based General Surgery Residencies

BACKGROUND There is a paucity of research comparing resident training experiences of university, community, and military-affiliated surgical programs. STUDY DESIGN We reviewed a cross-sectional national survey (NEARS) involving all US categorical general surgery residents (248 programs). Demographics and level of agreement regarding training experiences were collected. Statistical analysis included chi-square, ANOVA, and hierarchical logistic regression modeling (HLRM). RESULTS There were 4,282 residents included (82.4% response rate). The majority (69%) trained in university programs. Types of programs differed by sex mix (p < 0.001), racial makeup (p = 0.005), marital status profile (p = 0.002), and parental status profile (p < 0.001). Community residents were most satisfied with their operative experience (community 84.5%, university 73.4%, military 62.4%; p < 0.001), most likely to feel their opinions are important (76.0% vs 69.4% vs 67.9%, respectively; p < 0.001), and least likely to believe attendings will think worse of them if residents asked for help with patient management (12.6% vs 15.9% vs 14.7%, respectively; p = 0.025). Military residents were least likely to report that surgical training is too long (military 7.4%, community 14.0%, university 23.8%; p < 0.001). On HLRM, community programs were independently associated with residents feeling their opinions are important (odds ratio [OR] 1.91; p < 0.001), and reporting satisfactory operative experience (OR 4.73; p < 0.001). Residents training at military programs (OR 0.23; p = 0.002) or community programs (OR 0.31; p < 0.001) were less likely to feel that surgical training is too long, or that attendings will think worse of them if asked for help with patient care (community OR 0.19; p < 0.001; military OR 0.27; p = 0.004). CONCLUSIONS Residents at university, community, and military programs report distinct training experiences. These findings may inform programs of potential targeted strategies for enhanced support.

Predictors of microinvasion and its prognostic role in ductal carcinoma in situ

BACKGROUND We sought to determine factors predicting microinvasion and the prognostic role it plays in patients with ductal carcinoma in situ (DCIS). METHODS A retrospective cohort study of 205 consecutive patients presenting to the Yale Breast Center, New Haven, CT, was performed. RESULTS Fifty-one (24.9%) patients had microinvasion on pathology. Patients with microinvasion had larger areas of DCIS and were more likely to have high-grade DCIS of the comedo and solid type associated with necrosis and microcalcifications. On multivariate analysis, none of these factors were independent predictors of microinvasion. With a median follow-up of 8.5 years, there was no difference in the recurrence rate or 5-year actuarial survival between those with microinvasion vs those with pure DCIS. CONCLUSIONS Microinvasion was associated with more extensive DCIS, higher grade, comedo or solid histology, necrosis, and microcalcifications although none of these were found to be an independent predictor of microinvasion. Furthermore, the presence of microinvasion does not seem to significantly increase the risk of recurrence or decrease survival.

The Vulnerable Stage of Dedicated Research Years of General Surgery Residency: Results of a National Survey

OBJECTIVE To characterize the demographics and attitudes of US general surgery residents performing full-time research. DESIGN Cross-sectional national survey administered after the 2008 American Board of Surgery In-Service Training Examination. SETTING Two hundred forty-eight residency programs. PARTICIPANTS General surgery residents. INTERVENTION Survey administration. MAIN OUTCOMES MEASURES A third of categorical general surgery residents interrupt residency to pursue full-time research. To our knowledge, there exist no comprehensive reports on the attitudes of such residents. RESULTS Four hundred fifty residents performing full-time research and 864 postgraduate year 3 (PGY-3) clinical residents completed the survey. Thirty-eight percent of research residents were female, 53% were married, 30% had children, and their mean age was 31 years. Residency programs that were academic, large, and affiliated with fellowships had proportionally more research residents compared with other programs. Research and PGY-3 residents differed (P < .05) on 10 survey items. Compared with PGY-3 residents, research residents were less likely to feel they fit well in their program (86% vs 79%, respectively), that their program had support structures if they struggled (72% vs 64%), or that they could turn to faculty (71% vs 65%). They were more likely to feel training was too long (21% vs 30%) and that surgeons must be specialty trained (55% vs 63%). In multivariate analyses, research residents believed surgical training was too long (odds ratio, 1.36) and they fit in less well at their programs (odds ratio, 0.71) (P < .05). CONCLUSIONS Compared with PGY-3 residents, research residents report less satisfaction with important aspects of training, suggesting this is a vulnerable stage. Interventions could be targeted to facilitate support and better integration into the mainstream of surgical education.

Infantile hemangiomas exhibit neural crest and pericyte markers.

AbstractInfantile hemangiomas (IHs) are the most common benign tumors of infancy and occur with greater than 60% prevalence on the head and neck. Despite their prevalence, little is known about the pathogenesis of this disease. Given the predilection of hemangioma incidence on the face and its nonrandom distribution on embryological fusion plates, we postulated that IHs are derived from pericytes of the neural crest. We performed an analysis on 15 specimens at various stages of the IH progression. Experiments performed included immunohistochemical staining, immunofluorescent staining, quantitative real-time polymerase chain reaction, and flow cytometry. We analyzed a number of cell markers using these methods, including cell markers for the neural crest, pericytes, endothelial cells, stem cells, and the placenta. We observed that neural crest markers such as NG2 and nestin were expressed in the hemangioma samples, in addition tomultiple pericytes markers including &dgr;-like kinase, smooth muscle actin, calponin, and CD90. Stem cell markers such as c-myc, oct4, nanog, and sox2 were also more highly expressed in hemangioma samples compared to controls. Our work demonstrates that hemangiomas express pericyte, neural crest, and stem cell markers suggesting a possible pathogenetic mechanism.

Generation Y and the Integrated Plastic Surgery Residency Match: A Cross-sectional Study of the 2011 Match Outcomes.

Background: Plastic surgery is the most competitive specialty in medicine. We sought to identify factors associated with the successful match of generation Y applicants into integrated plastic surgery residency. Methods: We utilized the most recent data from the Charting Outcomes in the Match published by the National Resident Matching Program in 2011. We had data on US senior or independent applicant status, Alpha Omega Alpha (AOA) status, attendance of top 40 medical schools, advanced degree status, and number of contiguous ranks within plastic surgery. Our main outcome measure was match status. Results: A total of 81 out of 197 applicants (41.1%) successfully matched into integrated plastic surgery in the 2011 main match. US seniors matched at a significantly higher rate compared to independent applicants (44.0% vs 24.1%, P = 0.044). Matched US seniors were more likely to have AOA membership compared to unmatched US seniors (45.9% vs 27.7%, P = 0.014) and attend a top 40 medical school (52.7% vs 35.1%, P = 0.022). There were no differences in terms of advanced degrees between matched and unmatched US seniors. Unmatched US seniors were more likely to have 3 or fewer contiguous ranks of plastic surgery residency programs than matched US seniors (86.2% vs 68.9%, P = 0.007). Conclusions: US senior status, AOA membership, and attendance at a top 40 medical school are predictors of matching into integrated plastic surgery. Program directors need to be aware of the background of the millennial applicants to recruit and maintain top residents.

Factors associated with decision to pursue mastectomy and breast reconstruction for treatment of ductal carcinoma in situ of the breast

BACKGROUND Factors influencing the treatment of ductal carcinoma in situ with mastectomy and reconstruction are poorly understood. METHODS A retrospective cohort study of 196 patients presenting to one institution was performed. RESULTS Forty-seven patients (24.0%) were treated with mastectomy, while 149 (76.0%) underwent breast-conserving surgery. Of the mastectomy patients, 28 (59.6%) elected for reconstruction. On bivariate analysis, patients who opted for mastectomy were younger than those treated with breast-conserving surgery (median age, 51.8 vs. 56.5 years; P = .017) and had higher grade tumors (50.0% vs. 34.6% grade 3, P = .009). Among patients treated with mastectomy, those who opted for reconstruction were younger than those forgoing reconstruction (49.4 vs. 56.9 years, P = .024). Race, ductal carcinoma in situ tumor size, and histologic subtype were not associated with the decision to pursue mastectomy or reconstruction (P > .05 for all). CONCLUSIONS In patients with ductal carcinoma in situ, the decision to pursue mastectomy and reconstruction appears to be driven by younger patient age and higher tumor grade.

Leptin Is Produced by Parathyroid Glands and Stimulates Parathyroid Hormone Secretion

Objective: We asked if leptin and its cognate receptor were present in normal and diseased parathyroid glands, and if so, whether they had any functional effects on parathyroid hormone (PTH) secretion in parathyroid neoplasms. Background: The parathyroid glands acting through PTH play a critical role in the regulation of serum calcium. Based on leptins recently discovered role in bone metabolism, we hypothesized these glands were the sites of a functional interaction between these 2 hormones. Methods: From July 2010 to July 2011, 96 patients were enrolled in a prospective study of leptin and hyperparathyroidism, all of whom were enrolled based on their diagnosis of hyperparathyroidism, and their candidacy for surgical intervention provided informed consent. Immediately after parathyroidectomy, 100 to 300 mg of adenomatous or hyperplastic diseased parathyroid tissue was prepared and processed according to requirements of the following: in situ hybridization, immunohistochemistry, immunofluorescence by conventional and spinning disc confocal microscopy, electron microscopy, parathyroid culture, whole organ explant, and animal model assays. Results: Leptin, leptin receptor (long isoform), and PTH mRNA transcripts and protein were detected in an overlapping fashion in parathyroid chief cells in adenoma and hyperplastic glands, and also in normal parathyroid by in situ hybridization, qRT-PCR, and immunohistochemistry. Confocal microscopy confirmed active exogenous leptin uptake in cultured parathyroid cells. PTH secretion in explants increased in response to leptin and decreased with leptin receptor signaling inhibition by AG490, a JAK2/STAT3 inhibitor. Ob/ob mice injected with mouse leptin exhibited increased PTH levels from baseline. Conclusions: Taken together, these data suggest that leptin is a functionally active product of the parathyroid glands and stimulates PTH release.

Hueston Revisited: Use of Acellular Dermal Matrix Following Fasciectomy for the Treatment of Dupuytren's Disease

AbstractVarious surgical treatment modalities have been advocated for the treatment of Dupuytren’s disease. However, recurrence following surgical treatment of Dupuytren’s disease remains a common problem. Previous studies have demonstrated lower recurrence rates with use of a full-thickness skin graft. We therefore postulated that use of acellular dermal matrix may be associated with a similar outcome, based on the common inhibitory effect on underlying myofibroblasts. We performed a retrospective cohort study of 43 patients undergoing open fasciectomy for Dupuytren’s disease from years 2005 to 2012 at our academic institution. Standard fasciectomies of the affected palmar and digital fascia were performed via Brunner incisions on all patients. Patients in the experimental group had a sheet of acellular dermal matrix (Alloderm; LifeCell, Bridgewater, NJ) sutured into the surgical bed with interrupted absorbable sutures before closure, whereas patients in the control group were not closed with acellular dermal matrix. Patients were then evaluated at follow-up for disease recurrence, defined as presence of Dupuytren’s tissue in an area previously operated on with a contracture greater than that recorded following the surgical fasciectomy, or presence of contracture requiring surgery. Among our cohort of 43 patients, 23 (53.5%) were treated with acellular dermal matrix while 20 (46.5%) were not. The median age of our cohort was 66.5 years (range 54–91 years). The median follow-up was 1.8 years. During this follow-up period, recurrence of contracture was observed in 1 of 23 patients in the group receiving acellular dermal matrix, compared to 5 of 20 in the control group (P = 0.045). No differences in the incidence of minor wound complications were observed. Our novel technique of placement of acellular dermal matrix into the wound bed following fasciectomy for Dupuytren’s disease may be an important surgical strategy to reduce recurrence rates in patients with Dupuytren’s disease.

Absence of aneuploidy and gastrointestinal tumours in a man with a chromosomal 2q13 deletion and BUB1 monoallelic deficiency.

Chromosomal instability is a potentially critical step in the development of colorectal cancer. The budding uninhibited by benzimidazole 1 (BUB1) gene is a highly conserved protein that plays a critical role at the spindle assembly checkpoint during cell division. BUB1 mutations function in a dominant-negative fashion and have been implicated in causing dysfunctional kinetochore attachments, premature chromatid separation, accelerated mis-segregation of whole chromosomes and aneuploidy. BUB1 mutations have been observed in patients with colorectal cancers. We report a remarkable case of BUB1 haploinsufficiency owing to a 1.7 Mb deletion of chromosome 2q13 in a 54-year-old man with no prior history of carcinoma. These mutant alleles were observed in both tissue from the hand and peripheral blood. Aneuploidy was not observed on cytogenetic analysis. These findings highlight the insufficiency of BUB1 haploinsufficiency to directly stimulate tumourigenesis, and suggest that other factors may be more critical to this process.