Virtual Residency Interviews: A Survey of Anesthesiology Program Director Perspectives Amidst the COVID-19 Pandemic.

BACKGROUND: The COVID-19 pandemic caused a rapid pivot from in-person to virtual residency interviews across the United States. We present a survey we conducted about the attitudes and opinions of anesthesiology program directors with regard to the 2021 virtual interview process. METHODS: This was a 13-question online survey disseminated to 142 anesthesiology residency program directors in February 2021, asking them to compare the most recent interview cycle to their experience with prior cycles. RESULTS: There were 46 (37%) respondents. Generally, respondents saw an increase in applicants and reported perceiving worse interpersonal relationships with applicants, significantly so in programs with small resident classes. CONCLUSIONS: Past research has focused on the benefits of virtual interviews for the applicant, but these should be evaluated in tandem with increased difficulties for the interviewers.

Evaluation of Knowledge Acquisition with a Practice Management Course for Anesthesiology Residents: A Pilot Study.

Physicians routinely rely on nontechnical skills-including leadership ability, managerial skills and financial considerations-when delivering patient care. Efficient practice management is a commonplace expectation of attending anesthesiologists, but there is no uniform residency training to foster the expertise required to succeed in this endeavor. The purpose of this study is to evaluate a novel practice management course for anesthesiology residents. METHODS: Senior anesthesiology residents (Clinical Anesthesia-3) at The George Washington University were eligible to participate in a 1-month Ambulatory Anesthesiology-Practice Management Rotation focusing on the acquisition of nontechnical skills and knowledge applicable to becoming an effective clinical leader. The rotation included 1-week service as operating room manager, completion of an online module, assigned readings with follow-up discussions, and completion of a billing and reimbursement exercise. The interventions, in aggregate, were measured with a preknowledge and a postknowledge test. RESULTS: Twelve residents out of 14 (86%) completed the preknowledge and postknowledge tests. Residents scored significantly higher on the postcourse exam (61.49%, SD 18.65%) than the pretest (42.7%, SD 12.7%) (P < .004). CONCLUSION: A curriculum designed to develop the practice management skills required of a physician anesthesiologist is feasible and effective at improving knowledge within a 1-month, senior resident rotation.

Impact of social deprivation, demographics and centre on HbA1c outcomes with continuous subcutaneous insulin infusion.

AIMS: To assess the impact of social deprivation, demographics and centre on HbA1c outcomes with continuous subcutaneous insulin infusion (CSII) in adults with Type 1 diabetes. METHODS: Demographic data, postcode-derived English Index of Multiple Deprivation data and 12-month average HbA1c (mmol/mol) pre- and post-CSII were collated from three diabetes centres in the north west of England, University Hospital of South Manchester (UHSM), Salford Royal Foundation Hospital (SRFT) and Manchester Royal Infirmary (MRI). Univariable and multivariable regression models explored relationships between demographics, Index of Multiple Deprivation, centre and HbA1c outcomes. RESULTS: Data were available for 693 (78%) individuals (UHSM, n = 90; SRFT, n = 112; and MRI, n = 491) of whom 59% were women. Median age at CSII start was 39 (IQR 29.5-49.0) years and median diabetes duration was 20 (11-29) years. Median Index of Multiple Deprivation was 15 193 (6313-25 727). Overall median HbA1c improved from 69 to 64 mmol/mol (8.5% to 8.0%) within the first year of CSII. In multivariable analysis, higher pre-CSII HbA1c was significantly associated with higher deprivation (P = 0.036), being female (P < 0.001), and centre (MRI; P = 0.005). Following pre-CSII HbA1c adjustment, post-CSII HbA1c or HbA1c change were not related to demographic factors and deprivation, but remained significantly related to the centre; UHSM and SRFT had larger reductions in HbA1c with CSII compared with MRI [median -7.0 (-0.6%) vs. -6.0 (-0.55%) vs. -4.5 (-0.45%) mmol/mol; P = 0.005]. CONCLUSIONS: Higher pre-CSII HbA1c levels were associated with higher deprivation and being female. CSII improves HbA1c irrespective of social deprivation and demographics. Significant differences in HbA1c improvements were observed between centres. Further work is warranted to explain these differences and minimize variation in clinical outcomes with CSII.

Comparison of different insulin pump makes under routine care conditions in adults with Type 1 diabetes.

AIMS: To compare long-term HbA1c changes associated with different insulin pumps during routine care in a large cohort of adults with Type 1 diabetes representative of other clinic populations. METHODS: Observational, retrospective study of 508 individuals starting pump therapy between 1999 and 2014 (mean age, 40 years; 55% women; diabetes duration, 20 years; 94% Type 1 diabetes; median follow-up, 3.7 years). Mixed linear models compared covariate-adjusted HbA1c changes associated with different pump makes. RESULTS: The pumps compared were: 50% Medtronic, 24% Omnipod, 14% Roche and 12% Animas. Overall HbA1c levels improved and improvements were maintained during a follow-up extending to 10 years (HbA1c : pre-continuous subcutaneous insulin infusion (pre-CSII) vs. 12 months post CSII, 71 (61, 82) vs. 66 (56, 74) mmol/mol; 8.7 (7.7, 9.6) vs. 8.2 (7.3, 8.9)%; P < 0.0001). The percentage of individuals with HbA1c ≥ 64 mmol/mol (8.0%) reduced from a pre-CSII level of 68% to 55%. After adjusting for baseline confounders, there were no between-pump differences in HbA1c lowering (P = 0.44), including a comparison of patch pumps with traditional catheter pumps (P = 0.63). There were no significant (P < 0.05) between-pump differences in HbA1c lowering in pre-specified subgroups stratified by pre-pump HbA1c , age or diabetes duration. HbA1c lowering was positively related to baseline HbA1c (P < 0.001) and diabetes duration (P = 0.017), and negatively related to the number of years of CSII use (P = 0.024). CONCLUSIONS: Under routine care conditions, there were no covariate-adjusted differences in HbA1c lowering when comparing different pump makes, including a comparison of patch pumps vs. traditional catheter pumps. Therefore, the choice of CSII make should not be influenced by the desired degree of HbA1c lowering.

Early post-operative psychosocial and weight predictors of later outcome in bariatric surgery: a systematic literature review.

This is the first systematic review to synthesize the evidence concerning early post-operative variables predictive of later weight and psychosocial outcomes in bariatric surgery. Eight electronic databases for empirical studies were searched (1954 to 2016). Most of the 39 included studies reported solely on weight outcomes; eating and psychosocial outcomes were less common. A better early weight loss trajectory was the most consistent predictor of more successful medium-term weight outcome (≤24 months); however, its relationship to longer term weight loss maintenance is less certain. Early eating adaptation may be associated with later weight loss, but further research is needed. Evidence is lacking for associations between early adherence or early psychosocial variables and later outcome. In particular, the relationship between early post-operative depression and later weight remains unclear. Little research has considered early prediction of later eating or psychosocial outcomes. Consideration of mediating or moderating relationships is lacking. The body of evidence is limited, and synthesis is hampered by heterogeneity in the type and time at which predictors and outcomes are measured and quality of statistical reporting. Further research on prospective prediction of bariatric surgery outcome is needed to guide early post-operative intervention for those at greatest risk of poor outcomes.

Resistin expression correlates with steatohepatitis in morbidly obese patients.

BACKGROUND: Morbidly obese patients are at risk for nonalcoholic steatohepatitis (NASH) even in the absence of risk factors for liver disease. Unfortunately, NASH is usually not clinically evident, and a definitive, noninvasive test for NASH does not exist. Resistin, a cytokine originating from adipose tissue, is involved in insulin resistance and also initiates proinflammatory signaling from hepatic stellate cells. This study explores the relationship between resistin expression and liver pathology in bariatric surgery patients. METHODS: Blood samples from 30 patients undergoing bariatric surgery were collected. Total RNA was extracted and cDNA was synthesized. Quantitative RT-PCR was used to quantify relative gene expression using 18s rRNA gene as an internal control. Wedge liver biopsies from these patients were sectioned and stained. Based on a previously published scoring method, biopsies were assigned an overall NASH severity score and subscores for steatosis, inflammation, and fibrosis. Results were analyzed by using Student's t test. RESULTS: Resistin mRNA levels ranged from 0.5 to 9.7. A group of five patients with very high resistin expression (>4) was identified. These patients had a significantly higher average NASH score compared with the rest of the group (7.9 vs. 4.48, p = 0.019). Steatosis and inflammation scores were significantly higher in the high-resistin group (p < 0.05 for both comparisons). There also was a trend toward higher fibrosis score in this group, which approached statistical significance (p = 0.051). CONCLUSIONS: In morbidly obese patients, high resistin expression in serum is associated with hepatic steatosis, inflammation, and fibrosis. The development of elevated resistin expression may represent a link between obesity and the onset of steatohepatitis.

Downregulation of leptin and resistin expression in blood following bariatric surgery.

BACKGROUND: Type 2 diabetes (T2D) resolves rapidly after bariatric surgery, even before substantial weight is lost. However, the molecular pathways underlying this phenomenon remain unclear. Microarray data has shown that numerous genes are differentially expressed in blood after bariatric surgery, including resistin and leptin. Resistin and leptin are circulating hormones derived from adipose tissue, which are associated with obesity and insulin resistance. This study examined expression of these genes before and after bariatric surgery in diabetic and nondiabetic obese patients. METHODS: The study included 16 obese patients who underwent bariatric surgery, either Roux-en-Y gastric bypass (RYGB) or adjustable gastric banding. Eight patients had T2D. Preoperative blood samples were collected in PAXgene tubes to stabilize mRNA. Postoperative samples were collected 3 months after surgery. Total RNA was isolated and cDNA was synthesized. Real-time quantitative PCR was used to quantify mRNA. Results were analyzed using Student's t test with a P<0.05 considered significant. RESULTS: Postoperatively, five diabetic patients had discontinued hypoglycemic medications and one showed improved glycemic control. Both leptin and resistin mRNA levels were elevated in the diabetic group but decreased after surgery to levels near those of the nondiabetic group. Greater downregulation of resistin and leptin expression occurred in patients who lost more excess body weight (EBW), while patients who lost less than 10% EBW had a mean increase in expression of the two genes. Downregulation of both genes was more pronounced after RYGB compared to gastric banding. CONCLUSIONS: Downregulation of resistin and leptin gene expression after bariatric surgery may play a role in normalizing obesity-associated insulin resistance. Interestingly, downregulation is greater after RYGB and in patients who lose a greater proportion of EBW. Targeted therapies for obesity and diabetes may be developed by understanding the pathways by which these adipocytokines contribute to obesity and T2D.

BP1 Homeoprotein Enhances Metastatic Potential in ER-negative Breast Cancer.

Tumor invasion and metastasis remain a major cause of mortality in breast cancer patients. It was reported that BP1, a homeobox isoform of DLX4, is overexpressed in 80% of breast cancer patients and in 100% of estrogen receptor negative (ER-) tumors. The prevalence of BP1 positive cells and the intensity of BP1 immunoreactivity increased with the extent of ductal proliferation and tumorigenesis. These findings imply that BP1 may play an important role in ER- breast cancer. We sought to determine the effects and mechanisms of BP1 on cell proliferation and metastasis using ER- Hs578T cells as a model. Cells were transfected with either pcDNA3.2 plasmid containing BP1 gene, or pcDNA3.2 vector, then selected and cloned. Overexpression of BP1 increased cell proliferation rate by 2-5 fold (p<0.005), and enhanced the in vitro invasive activity by 25-65 fold (p<0.001). Microarray experiments were performed to identify differentially expressed genes when BP1 is overexpressed. The gene expression profile of the transfected cell lines were compared, resulting in 71 differentially expressed genes with a fold-change of >=2.0. Of those genes, 49 were up-regulated and 22 were down-regulated. Significant pathways were identified involving cell proliferation and metastasis. These data demonstrated that overexpression of BP1 significantly enhanced cell proliferation and metastatic potential in ER- Hs578T cells. Further analysis with more ER- cell lines and patient samples is warranted to establish BP1 as a therapeutic target for ER- breast cancer.

Skin microbial flora and effectiveness of aseptic technique for deep muscle biopsies in Weddell seals (Leptonychotes weddellii ) in McMurdo Sound, Antarctica.

Deep muscle biopsies were collected from the pectoralis and longissimus dorsi of wild Weddell seals (Leptonychotes weddellii) in McMurdo Sound, Antarctica, during October-December 2007. Sterile swabs were collected from the surface of each skin site before biopsy and from the deep-needle path after biopsy. No growth occurred in two of six pectoralis and three of six longissimus skin sites, or in four of 10 pectoralis deep biopsy and eight of 12 longissimus deep-biopsy sites. Positive skin culture was not predictive of deep-biopsy contamination, nor did contamination at one body location correlate with contamination at the second site. Psychrobacter species were most common in one or more samples from each of the four sample types. Only one of the eight documented bacteria exhibited resistance to commonly used antibiotics.

Identification of cardiovascular genes in omentum from morbidly obese patients with type 2 diabetes.

BACKGROUND: The metabolic syndrome describes the association between obesity and co-morbidities including insulin resistance, hypertension, dyslipidemia, and cardiovascular (CV) disease. Adipokines produced from omentum contribute to the risk of CV disease and increase the inflammatory state. This study examines the gene expression differences in the omental tissue of morbidly obese diabetic and non-diabetic patients. METHODS: Twenty morbidly obese patients undergoing bariatric surgery were included. Ten patients were diabetic and 10 were non-diabetic. Omental samples were collected intraoperatively and snap frozen. Total RNA was extracted using the Trizol reagent and purified with the RNeasy kit (Qiagen). Microarray experiments were performed using the Affymetrix Gene 1.0 ST array and data was analyzed with the Partek 6.3 program using an unpaired t-test (P<0.05). The gene expression profiles of the diabetic group were compared with the non-diabetic group. Using the Ingenuity program, the gene list generated from the microarray analysis was evaluated and real-time quantitative PCR (qPCR) was used to validate the array data. RESULTS: Compared with the non-diabetic group, the diabetic obese patients showed 79 upregulated genes and 4 downregulated genes with >1.4-fold difference in expression. Ingenuity analysis showed numerous dysregulated genes associated with CV disease including leptin, Von Willebrand factor, P-selectin, angiopoietin-1 (ANGPT1), phospholipase A2 (group VII), and periostin osteoblast specific factor. Microarray results for the earlier mentioned genes were confirmed with qPCR. The results were analyzed with respect to the presence or absence of hyperlipidemia, hypertension, and coronary artery disease. In patients with hyperlipidemia, ANGPT1 and P-selectin were upregulated 1.9- and 2.9-fold, respectively. CONCLUSIONS: This microarray analysis of omental tissue from morbidly obese diabetic patients documents a host of upregulated genes related to CV disease. This study provides further evidence that diabetic status predisposes obese patients to a higher risk of developing CV disease.

Reactivation of adiponectin expression in obese patients after bariatric surgery.

BACKGROUND: Bariatric surgery can resolve type 2 diabetes in morbidly obese patients. However, the underlying mechanism is unknown. This study aimed to identify potential biomarkers or molecular pathways that are altered after bariatric surgery in diabetic and nondiabetic patients. METHODS: The study enrolled 17 morbidly obese patients undergoing bariatric surgery. Eight of the patients were diabetic, and nine were nondiabetic. In addition, a control group of four nonobese, nondiabetic volunteers was included. Patient blood samples were drawn before and after the operation. All blood samples were stabilized in Paxgene tubes (PreAnalytix). Total RNA was extracted and purified using the Paxgene Blood RNA Kit. For each sample, 100 ng of total RNA was amplified and labeled using the Ovation RNA Amplification System V2 with the Ovation Whole Blood reagent before hybridization to an Affymetrix Focus array containing more than 8,500 verified genes. Microarray results were analyzed with the GeneSpring GX 10.0 program, which uses an analysis of variance (ANOVA), and verified with real-time quantitative polymerase chain reaction (QPCR) using SYBR green (ABI). RESULTS: Microarray analysis showed that 167 genes were upregulated and 39 were downregulated in the obese diabetic patients. Preoperatively, adiponectin was downregulated 1.5-fold in diabetic versus nondiabetic patients. This was confirmed with quantitative PCR analysis. Preoperatively, morbidly obese patients showed a 3.12-fold downregulation of adiponectin expression versus the control group (p = 0.05). Interestingly, postoperative adiponectin levels were upregulated 2.79-fold (p = 0.02), which is close to the level of the normal control group. CONCLUSIONS: Adiponectin is dysregulated in obese patients and significantly dysregulated in obese diabetic patients. These findings correlate with the association between low levels of adiponectin and a predisposition to insulin resistance or diabetes. The data suggest that reactivation of adiponectin expression may play a part in the resolution of type 2 diabetes after bariatric surgery. Therefore, targeting adiponectin may help to develop alternative treatments for diabetes.

Anatomical measurements of the gastric cardia in obese patients.

BACKGROUND: Currently, surgeons implant a variety of laparoscopic adjustable gastric bands. However, there is little data to guide the selection process. This study aims to determine the relationship between a patient's body mass index (BMI), height, and weight and the anatomical measurements of the gastric cardia in morbidly obese patients undergoing laparoscopic adjustable gastric band (LAGB) surgery. METHODS: A total of 67 morbidly obese patients undergoing LAGB surgery were studied. Intraoperative measurements of the gastric cardia were obtained. The relative circumference and posterior diameter of the gastric cardia were measured along with the patient's height, weight, and BMI. Pearson's correlation coefficient was used to measure the relationship between the circumference and posterior diameter of the gastric cardia and the BMI, height, and weight. A p < 0.05 was considered significant. RESULTS: No correlation exists between a patient's BMI or weight and the circumference or diameter of the gastric cardia. A correlation exists between a patient's height and the posterior diameter of the gastric cardia (p = 0.02). Of note, there is a correlation between the relative circumference and the posterior diameter of the gastric cardia for each patient (p = 0.05). CONCLUSION: Our unique data show no significant correlation between a patient's BMI and weight and the measurements of the gastric cardia. There was a correlation between a patient's height and the posterior diameter of the gastric cardia. These intraoperative measurements may help surgeons objectively select the appropriate band for each respective patient undergoing LAGB surgery. This may potentially decrease postoperative dysphagia.

TCF7L2 expression in diabetic patients undergoing bariatric surgery.

INTRODUCTION: The cause of diabetes in morbidly obese patients is multifactorial, including genetic, social, and dietary components. Transcription factor 7-like 2 (TCF7L2) is a gene that is related to the development of diabetes. This pilot study examines TCF7L2 expression in liver samples obtained from morbidly obese patients undergoing bariatric surgery. TCF7L2 expression is compared between diabetic and nondiabetic patients. METHODS: Liver samples were obtained from 20 morbidly obese patients undergoing bariatric surgery. Samples were flash frozen in liquid nitrogen. Total RNA was extracted from tissue samples using the TRIzol reagent (Invitrogen Inc, Carlsbad, CA). Using the iScript cDNA synthesis kit (Bio-Rad Laboratories, Hercules,CA), cDNA was synthesized. Quantitative polymerase chain reaction (qPCR) was done using SYBR Green qPCR Reagents (Stratagene, Cedar Creek TX) and the 7300 Real-Time PCR system (Applied Biosystems, Foster City CA). Preoperative demographic and gene expression data were correlated using univariate analysis and logistic regression models. Only associations with a p-value less than 0.05 were considered significant. RESULTS: For the entire group, there was no correlation between body mass index (BMI) and TCF7L2 expression. In morbidly obese nondiabetic patients, there was a positive correlation between TCF7L2 expression and BMI (R(2)=0.21). In morbidly obese diabetic patients, there was an inverse correlation between TCF7L2 expression and BMI (R(2)=0.58). There was no significant relationship between TCF7L2 expression and age or glycosylated hemoglobin (HbA1c). CONCLUSIONS: The cause of diabetes is multifactorial but the data from our pilot study documents the relationship of TCF7L2 with type 2 diabetes in morbidly obese patients.

Thermal injury secondary to laparoscopic fiber-optic cables.

BACKGROUND: Laparoscopy requires a reliable light source to provide adequate visualization. However, thermal energy is produced as a by-product from the optical cable. This study attempts to quantify the degree of possible thermal damage secondary to the fiber-optic light source. METHODS: Using a digital thermometer, temperature measurements were recorded at the tip of optical cables from five different light sources (Karl Storz, Inc., Tuttlingen, Germany). Temperature measurements were recorded with new and old bulbs. The tip of the cable was applied to surgical drapes and the time to charring was recorded. Subsequently, the tip of the optical cable was applied to a porcine model and tissue samples were obtained after varying amounts of time (5, 15, 30, 60, and 90 s). Sections of the damaged tissue were prepared for microscopic evaluation. Parameters for thermal injury included extent of epidermal, dermal, and subcutaneous fat damage and necrosis. The lateral extent and depth of injury were measured. RESULTS: The maximum temperature at the tip of the optical cable varied between 119.5 degrees C and 268.6 degrees C. When surgical drapes were exposed to the tip of the light source, the time to char was 3-6 s. The degree and volume of injury increased with longer exposure times, and significant injury was recorded with the optical cable 3 mm from the skin. CONCLUSIONS: This study demonstrates that the temperature at the tip of the optical light cord can induce extensive damage. The by-product of light, heat, can produce immediate superficial tissue necrosis that can extend into the subcutaneous fat even when the optical tip is not in direct contact with the skin. In addition, our study shows the variation in temperature that exists between light sources and bulb status. Overall, surgeons must realize and respect the potential complications associated with optical technology.

Dysregulation of gene expression within the peroxisome proliferator activated receptor pathway in morbidly obese patients.

BACKGROUND: The causes of obesity are multifactorial but may include dysregulation of a family of related genes, such as the peroxisome proliferator activated receptor gamma (PPARgamma). When activated, the PPARgamma pathway promotes lipid metabolism. This study used microarray technology to evaluate differential gene expression profiles in obese patients undergoing bariatric surgery. METHODS: The study enrolled six morbidly obese patients with a body mass index (BMI) exceeding 35 and four nonobese individuals. Blood samples were stabilized in PaxGene tubes (PreAnalytiX), and total RNA was extracted. Next, 100 ng of total RNA was amplified and labeled using the Ovation RNA Amplification System V2 with the Ovation whole-blood reagent (NuGen) before it was hybridized to an Affymetrix (Santa Clara, CA) focus array containing more than 8,500 verified genes. The data were analyzed using an analysis of variance (ANOVA) (p < 0.05) in the GeneSpring program, and potential pathways were identified with the Ingenuity program. Real-time quantitative reverse transcriptase-polymerase chain reaction was used to validate the array data. RESULTS: A total of 97 upregulated genes and 125 downregulated genes were identified. More than a 1.5-fold change was identified between the morbidly obese patients and the control subjects for a cluster of dysregulated genes involving pathways regulating cell metabolism and lipid formation. Specifically, the PPARgamma pathway showed a plethora of dysregulated genes including tumor necrosis factor-alpha (TNFalpha). In morbidly obese patients, TNFalpha expression was increased (upregulated) 1.6-fold. These findings were confirmed using quantitative polymerase chain reaction with a 2.8-fold change. CONCLUSIONS: Microarrays are a powerful tool for identifying biomarkers indicating morbid obesity by analyzing differential gene expression profiles. This study confirms the association of PPARgamma with morbid obesity. Also, these findings in blood support previous work documented in tissue (omentum, liver, and stomach). Based on these findings in blood, the authors plan to explore postoperative changes in gene expression by analyzing blood samples after bariatric surgery. Ultimately, these findings may promote the development of therapeutic agents targeted to specific dysfunctional genes.

Body cooling and the diving capabilities of muskrats (Ondatra zibethicus): a test of the adaptive hypothermia hypothesis.

We tested the hypothesis that immersion hypothermia enhances the diving capabilities of adult and juvenile muskrats by reducing rates of oxygen consumption (V O2). Declines in abdominal body temperature (T(b)) comparable to those observed in nature (0.5-3.5 degrees C) were induced by pre-chilling animals in 6 degrees C water. Pre-chilling did not reduce diving V O2 of any animal tested in 10 degrees C or 30 degrees C water, irrespective of the nature of the dive. Most behavioural indices of dive performance, including average and cumulative dive times, were unaffected by T(b) reduction in adults, but depressed in hypothermic juveniles (200-400 g). Hypothermia reduced diving heart rate only on short (<25s) dives (16% reduction, P=0.01), but did not affect the temporal onset of diving bradycardia. Post-immersion V O2 was higher for pre-chilled than for normothermic muskrats, but the difference became insignificant on longer (>90 s) dives. Our findings suggest that the mild hypothermia experienced by muskrats in nature has minimal effect on diving and post-immersion metabolic costs, and thus has little impact on the dive performance of this northern semi-aquatic mammal.

Dimensional changes in acid-demineralized dentin matrices following the use of HEMA-water versus HEMA-alcohol primers.

Although dried acid-etched dentin can be reexpanded by hydroxyethyl methacrylate (HEMA)/water primers, the primed dentin collapses when the water is evaporated. Experimental HEMA/alcohol primers should stiffen the matrix and permit less shrinkage when the solvent is evaporated. The purpose of this study was to test the hypotheses that matrix shrinkage induced by solvent evaporation from HEMA primers is inversely related to solvent-induced matrix stiffness. Dentine discs were prepared from midcoronal dentine of unerupted human third molars. After demineralization in 37% phosphoric acid, the specimens were placed in the well of a linear variable differential transformer instrument, which measures changes in the matrix height and stiffness by load displacement after the application of weights. This was done in their hydrated state after water had been applied, after drying with dry nitrogen gas, and after the application of 35 vol % HEMA-water, HEMA-methanol, HEMA-ethanol, or HEMA-propanol primers. The degree of reexpansion after the application of the primers to the dentine in the dried state was found to be highest using the HEMA-water primer, followed by HEMA-methanol and HEMA-ethanol, with the HEMA-propanol primer producing no expansion. However, when the solvents were evaporated the HEMA-water-treated specimens shrank the most, the HEMA-ethanol-treated specimens shrank an intermediate amount, and the HEMA-methanol-treated specimens shrank the least. The net result of expansion minus shrinkage produced by evaporation determines how much HEMA remains in the hybrid layer just prior to polymerization.

Assembly of microarrays for genome-wide measurement of DNA copy number.

We have assembled arrays of approximately 2,400 BAC clones for measurement of DNA copy number across the human genome. The arrays provide precise measurement (s.d. of log2 ratios=0.05-0.10) in cell lines and clinical material, so that we can reliably detect and quantify high-level amplifications and single-copy alterations in diploid, polyploid and heterogeneous backgrounds.

Resource allocation modelling for home-based health and social care services in areas having differential population density levels: a case study in Northern Ireland.

This project arose from deliberations within the Department of Health and Social Services (DHSS) in Northern Ireland concerning the acceptability of the revenue resource allocation methodology they were using. One problem with the method being used had been the absence of a component that adequately reflected the relative costs associated with the differential population densities of the four health boards into which the Province is divided. This study investigates a particular element of this issue, viz differences in the travelling distances and times of those health and social service professionals who provide visiting services to patients in their own homes. A modelling approach has been developed and used in conjunction with a comprehensive spatial and geographical information system for Northern Ireland. An important outcome of the study has been estimates of the targets that should be set for the annual health and social care travelling distances and times per head of population in the boards, for a range of home-based services. Also, the project has contributed to decisions made by the DHSS in Northern Ireland concerning the annual financial compensations required by boards for costs associated with their relative population densities.