Integrating genetics with single-cell multiomic measurements across disease states identifies mechanisms of beta cell dysfunction in type 2 diabetes

Dysfunctional pancreatic islet beta cells are a hallmark of type 2 diabetes (T2D), but a comprehensive understanding of the underlying mechanisms, including gene dysregulation, is lacking. Here we integrate information from measurements of chromatin accessibility, gene expression and function in single beta cells with genetic association data to nominate disease-causal gene regulatory changes in T2D. Using machine learning on chromatin accessibility data from 34 nondiabetic, pre-T2D and T2D donors, we identify two transcriptionally and functionally distinct beta cell subtypes that undergo an abundance shift during T2D progression. Subtype-defining accessible chromatin is enriched for T2D risk variants, suggesting a causal contribution of subtype identity to T2D. Both beta cell subtypes exhibit activation of a stress-response transcriptional program and functional impairment in T2D, which is probably induced by the T2D-associated metabolic environment. Our findings demonstrate the power of multimodal single-cell measurements combined with machine learning for characterizing mechanisms of complex diseases.

Integration of single-cell multiomic measurements across disease states with genetics identifies mechanisms of beta cell dysfunction in type 2 diabetes

Altered function and gene regulation of pancreatic islet beta cells is a hallmark of type 2 diabetes (T2D), but a comprehensive understanding of mechanisms driving T2D is still missing. Here we integrate information from measurements of chromatin activity, gene expression and function in single beta cells with genetic association data to identify disease-causal gene regulatory changes in T2D. Using machine learning on chromatin accessibility data from 34 non-diabetic, pre-T2D and T2D donors, we robustly identify two transcriptionally and functionally distinct beta cell subtypes that undergo an abundance shift in T2D. Subtype-defining active chromatin is enriched for T2D risk variants, suggesting a causal contribution of subtype identity to T2D. Both subtypes exhibit activation of a stress-response transcriptional program and functional impairment in T2D, which is likely induced by the T2D-associated metabolic environment. Our findings demonstrate the power of multimodal single-cell measurements combined with machine learning for identifying mechanisms of complex diseases.

Are Large Intraoperative Fill Volumes Associated With Increased Complications After Tissue Expander Placement?

Background

With the increased adoption of skin-sparing mastectomies, immediate 2-stage breast reconstruction is a common option for breast cancer patients. During the first stage of the procedure with tissue expander placement, higher intraoperative percent fill has been identified as a risk factor for complications. However, the postoperative outcomes of higher intraoperative fill volumes are not well established. The authors sought to evaluate if a higher initial intraoperative tissue expander fill volume is associated with higher complication rates in patients undergoing immediate breast reconstruction with tissue expander placement.

Methods

A retrospective review of patients who underwent immediate breast reconstruction with a tissue expander placement from 2016 to 2018 was conducted. Patient demographics and perioperative data were recorded. Large intraoperative fill was defined as saline fill volume greater than 350 mL. The primary outcome evaluated was skin and nipple necrosis. Secondary outcomes were major infections, minor infections, seroma, and hematoma.

Results

A total of 147 breasts in 86 patients were included. Mean intraoperative fill volume was 246.4 ± 106.6 mL. Thirty-five tissue expanders were filled with greater than 350 mL of saline intraoperatively. Patients with large intraoperative fill volume were older (mean age, 52.6 vs 47.9 years; P = .04), had a higher mean body mass index (BMI; 33.2 vs 25.9 kg/m²; P < .0001), and had larger preoperative breast anthropometrics (P < .0001). During a mean follow-up period of 20.1 months (range, 3-55 months), 9 breasts were noted to have skin/nipple necrosis. After multivariate analysis, large tissue expander fill volume was not a significant predictor of skin or nipple necrosis (P = .62). Hypertension and anticoagulant use were associated with increased skin and nipple necrosis (P = .04 and P = .03, respectively). Large fill volume was not associated with statistically significant increases in rates of other complications like major infections, minor infections, seroma, or hematoma.

Conclusions

Larger fill volumes are often required and benefit patients with higher BMI or bra sizes. This also reduces the number of postoperative fills required. In this patient population, larger intraoperative tissue expander saline fill volume (greater than 350 mL) was not associated with increased postoperative complications. After careful patient selection and perfusion evaluation, larger fill volumes may be considered a safe option to improve the aesthetic outcomes in patients with high BMI.

Is Irradiated Homologous Costal Cartilage Reliable? A Meta-Analysis of Complication Rates in Rhinoplasty

Background: Irradiated homologous costal cartilage (IHCC) may be a convenient, cost-effective and efficient alternative source of graft material in rhinoplasty; however, a systematic review and meta-analysis on this topic have not been previously performed. Objectives: We sought to summarize and pool data on complications associated with the use of IHCC grafting in rhinoplasty. Methods: A systematic review and meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. We conducted PubMed, Cochrane, Embase, Web of Science database searches, and screened articles using specific inclusion and exclusion criteria. Pooled complication rates were analyzed using a random-effects model. Results: Of the 13 studies that met criteria for systematic review, 11 studies involving 1017 patients, with 1956 IHCC grafts used, were included in the meta-analysis. Mean follow-up across all studies was 47 months. Overall, the pooled complication rates were 1.14% (95% CI: 0.3%-2.0%) for resorption, 0.5% (95% CI: 0.1%-0.9%) for warping, 1.2% (95% CI: 0.3%-2.1%) for infection, 1.0% (95% CI: 0.1%-2.0%) for mobility, and 0.8% (95% CI: 0.1%-1.6%) for graft removal or replacement. No allergic reactions or systemic disease associated with IHCC use were reported in any of the studies. Conclusions: The overall complications associated with IHCC use in rhinoplasty were very low. Costal cartilage allografts are an area of renewed interest that may represent an alternative to autologous costal cartilage grafting in rhinoplasty due to their low complication rates, convenience, cost-effectiveness, and elimination of donor-site complications.

Compliance With Surgical Oncology Specialty Care at a Safety Net Facility

BACKGROUND

Social determinants of health challenge in at-risk patients seen in safety net facilities.

STUDY DESIGN

We performed a retrospective review of surgical oncology specialty clinic referrals at a safety net institution evaluating referral compliance and times to first appointment and initiation of definitive treatment. Main outcomes measured included completion of initial visit, initiation of definitive treatment, time from referral to first appointment, and time from first appointment to initiation of definitive treatment.

RESULTS

Of 189 new referrals, English was not spoken by 52.4% and 69.4% were Hispanic. Patients presented without insurance in 39.2% of cases. Electronic patient portal was accessed by 31.6% of patients. Of all new referrals, 55.0% arrived for initial consultation and 53.4% initiated definitive treatment. Malignant diagnosis (P < .0001) and lack of insurance (P = .01) were associated with completing initial consultation. Initiation of definitive treatment was associated with not speaking English (P = .03), malignant diagnosis (P < .0001), and lack of insurance (P = .03). Times to first appointment and initiation of definitive treatment were not significantly affected by race/ethnicity, language, insurance, treatment recommended, or electronic patient portal access.

CONCLUSION

Access to surgical oncology care for at-risk patients at a safety net facility is not adversely affected by lack of insurance, primary spoken language, or race/ethnicity. However, a significant proportion of all patients fail to complete the initial consultation and definitive treatment. Lessons learned from safety net facilities may help to inform disparities in health care found elsewhere.

Financial Decisions and Reopening a Practice During the COVID-19 Pandemic: A Survey of California Plastic Surgeons

BACKGROUND

On March 11, 2020, the World Health Organization declared COVID-19 as a global pandemic. As a response, the United States shut down public gatherings and businesses in an effort to quarantine. This included the stopping of elective operations, which greatly affected plastic surgeons and their practices during the initial shutdown.

OBJECTIVES

We aim to study the early impact of COVID-19 on the financial implications and practice patterns of plastic surgeons in the state of California during the initial shutdown of elective surgery and provide guidelines for effective management during future crises.

METHODS

A 20-question survey was sent using Qualtrics XM software to 851 surgeon members of the California Society of Plastic Surgeons. The survey was open from May 13, 2020, to May 29, 2020. Standard statistical analysis was completed to compare private practice and nonprivate practice plastic surgeons.

RESULTS

We had a total of 140 respondents to our survey for a 16.5% response rate. The majority (77.1%) of the respondents were in a private practice setting. Private practice plastic surgeons reported a higher financial impact with a 79% reduction in financial income compared with nonprivate practice plastic surgeons at a 37% reduction (P < 0.0001). Additionally, private practice plastic surgeons demonstrated a higher reduction in case volume and were more likely to lay off or furlough staff, close their practice, and apply for loans (P < 0.001).

CONCLUSIONS

Our survey study showed that private practice plastic surgeons in the state of California faced the most financial hardship during the early shutdown of the COVID-19 pandemic. It serves as a valuable snapshot in our economic history and depicts the heavy financial impact of the stopping of elective surgery. Since the reopening of practices, new guidelines have been implemented to maintain safe elective surgery while the pandemic continues. Further follow-up studies on both the state and national level need to be completed to see the continued financial effects on private and nonprivate plastic surgery practices since the reopening and resumption of elective surgery.

Comparison of Acellular Solutions for Ex-situ Perfusion of Amputated Limbs

INTRODUCTION

Hypothermic ex-situ machine perfusion (MP) has been shown to be a promising alternative to static cold storage (SCS) for preservation of solid organs for transplantation and vascularized composite allotransplantation. Perfusion with blood-based perfusion solutions in austere environments is problematic due to their need for appropriate storage and short shelf life, making it impractical for military and emergency use. Acellular perfusion has been shown to be effective, but the ideal perfusate solution for MP of amputated limbs is yet to be determined. The purpose of this study is to evaluate the efficacy of alternative perfusate solutions, such as dextran-enriched Phoxilium, Steen, and Phoxilium in ex-vivo hypothermic MP of amputated limbs in a porcine model.

MATERIALS AND METHODS

Amputated forelimbs from Yorkshire pigs (n = 8) were preserved either in SCS (n = 2) at 4°C for 12 hours or machine-perfused at 10°C for 12 hours with oxygenated perfusion solutions (n = 6) at a constant flow rate. The perfusates used include modified Steen-solution, Phoxilium (PHOX), or Phoxilium enriched with dextran-40 (PHODEX). The perfusate was exchanged after 1 and 6 hours of perfusion. Machine data were recorded continuously. Perfusate samples for clinical chemistry, blood gas analysis, and muscle biopsies were procured at specific timepoints and subsequently analyzed. In this semi in-vivo study, limb replantation has not been performed.

RESULTS

After amputation, every limb was successfully transferred and connected to our perfusion device. The mean total ischemia time was 77.5 ± 5.24 minutes. The temperature of the perfusion solution was maintained at 10.18 ± 2.01°C, and perfusion pressure at 24.48 ± 10.72 mmHg. Limb weight increased by 3% in the SCS group, 36% in the PHODEX group, 25% in the Steen group, and 58% in the PHOX group after 12 hours. This increase was significant in the PHOX group compared with the SCS group. All perfusion groups showed a pressure increase of 10.99 mmHg over time due to edema. The levels of HIF-1a decreased over time in all groups except the Steen and the PHODEX group. The biomarkers of muscle injury in the perfusate samples, such as creatine kinase and lactate-dehydrogenase, showed a significant difference between groups, with highest values in the PHODEX group. No significant differences were found in the results of the blood gas analysis.

CONCLUSION

With the exception of significantly higher levels of creatine kinase and lactate dehydrogenase, MP with dextran-enriched Phoxilium provides similar results as that of the commercially available perfusates such as Steen, without the need for cold storage, and at circa 5% of the cost of the Steen solution. Further large-scale replantation studies are necessary to evaluate the efficacy of dextran-enriched Phoxilium as an alternate perfusate solution.

Combined (endo-)vascular intervention and microsurgical lower extremity free flap reconstruction-A propensity score matching analysis in 5386 ACS-NSQIP patients

BACKGROUND

Compromised lower limb perfusion due to vascular changes such as peripheral artery disease impedes wound healing and may lead to large-scale tissue defects and lower limb amputation. In such patients with defects and compromised or lacking recipient vessels, combined vascular reconstruction with free flap transfer is an option for lower extremity salvage.

METHODS

By using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2005-2018), we analyzed two patient cohorts undergoing (A) free flap lower limb reconstruction (LXTR) only and (B) combined (endo-)vascular reconstruction (vascLXTR). The preoperative variables assessed included demographic data and comorbidities, including smoking, diabetes mellitus, preoperative steroid use, and American Society of Anesthesiology (ASA) Physical Status Classification. Using a neighbor matching algorithm, we performed a 1:1 propensity score matching of 615 LXTR patients and 615 vascLXTR patients. Bivariate analysis for postoperative surgical and medical complications was performed for outcomes in the propensity-matched cohort.

RESULTS

We identified 5386 patients who underwent microsurgical free flap reconstruction of the lower extremity. A total of 632 patients underwent a combined (endo-)vascular intervention and lower extremity free flap reconstruction. Diabetes and smoking were more prevalent in this group, with 206 patients having diabetes (32.6%) and 311 being smokers (49.2%). More patients returned to the operating room in the cohort that underwent a combined vascular intervention (24.4% versus 9.9%; p<0.0001). The 30-day mortality for patients undergoing a combined vascular procedure was 3.5%, compared with 1.3% with free tissue transfer only (p<0.0001).

CONCLUSION

Despite the risks associated, the combined intervention decreases the very high mortality associated with limb amputation in severely sick patient populations. Careful preoperative assessment of modifiable risk factors may reduce complication rates while allowing limb salvage.

Do Better Operative Reports Equal Better Surgery? A Comparative Evaluation of Compliance With Operative Standards for Cancer Surgery

To improve the quality of cancer operations, the American College of Surgeons published Operative Standards for Cancer Surgery, which has been incorporated into Commission on Cancer (CoC) accreditation requirements. We sought to determine if compliance with operative standards was associated with technical surgical outcomes. Oncologic operative reports from 2017 at a CoC and non-CoC institution were examined for documentation of Operative Standards essential steps. Lymph node (LN) yield for lung and colon cases and re-excision rates for breast cases were recorded. Correct documentation was poor for colon, breast, and lung cases with numerous elements documented in <10% of operative reports at both centers. For lung cases, there was no significant difference in meeting ≥10 LN benchmark or average LN yield between the 2 institutions. For colon cases, average lymph node yield was lower in the non-CoC facility, but there was no significant difference in meeting ≥12 LN benchmark. For breast cases, re-excision rates were similar in both programs. Many essential steps in Operative Standards were poorly documented in operative reports, regardless of CoC status. Achieving benchmark technical surgical outcomes was not associated with documented compliance with these standards. Whether improved documentation leads to better surgical outcomes requires further investigation.

Impact of Robotic Surgery on Residency Training for Herniorrhaphy and Cholecystectomy

Robotic surgery has increased for common general surgery procedures. This study evaluates how robotic use affects the case distributions of herniorrhaphy and cholecystectomy for general surgery residents according to postgraduate year (PGY). We reviewed Accreditation Council for Graduate Medical Education (ACGME) biliary or hernia cases logged by surgical residents in the academic year 2017-2018. Operative reports were reviewed to compare approaches (robotic, laparoscopic, and open) by resident role and PGY level. Open cholecystectomies were excluded. Overall, 470 hernia and 657 cholecystectomy cases were logged. Hernia repairs were performed robotically in 15.9%, laparoscopically in 9.5%, and open in 74.7%. Cholecystectomies were performed robotically in 16.4% and laparoscopically in 83.6%. Residents were teaching assistants in 1.8% of hernia repairs and 1.5% of cholecystectomies. Distribution of cases by technique and PGY level was significantly different for both procedures, with chief residents performing the majority of robotic cholecystectomies (52.6%, P < .0001) and hernia repairs (59.7%, P < .0001). Migration of robotic cases to senior resident level and low percentage of teaching assistant roles held by residents suggest exposure to common operations may be delayed during general surgery residency training. Introduction of new technology in surgical training should be carefully reviewed and may benefit from a structured curriculum.

Long-Term Outcomes of Ventral Hernia Repair: An 11-Year Follow-Up

Background: Ventral hernia repair (VHR) is one of the most common general surgery procedures; however, few studies with long-term follow-up of VHR outcomes exist.

Methods: We performed a retrospective review of VHRs performed from 2000 to 2009 at a single institution. Our primary outcome was recurrence, and secondary outcomes were reoperations and complications including seroma, hematomas, abdominal wall abscess, wound infections, and mesh infections.

Results: Our sample population (n=420; mean age 46.3±11.7 years) included 230 females (54.8%), and cases included laparoscopic (n=31; 7.5%), laparoscopic converted to open (n=7; 1.7%), and open (n=373, 90%). As compared to suture repairs, mesh repair was associated with lower rates of complications (25.7% vs 29.5%, p=0.10) and recurrence (12.8% vs 15.2%, p=0.67). Laparoscopic repairs had lower rates of complications than open repairs (25% vs 26.8%; p=0.70) but similar rates of recurrence (13.8% and 13.6%; p=0.53). After logistic regression, obesity, chronic obstructive pulmonary disease, component separation technique, and prolonged operating time (>75th percentile) were associated with increased complications.

Conclusion: Obesity is a modifiable risk factor and must be addressed in patients undergoing VHRs. Mesh repair does not increase the risk of adverse long-term outcomes and may be performed safely in patients undergoing VHR.

Use of venous couplers in microsurgical lower extremity reconstruction: A systematic review and meta-analysis

BACKGROUND

Free tissue transfer for lower limb reconstruction has become a workhorse procedure for limb-salvage. Compared with other recipient sites, the lower extremity has a higher risk of microvascular complications, in particular with venous anastomosis. The study's objective is to evaluate the evidence, safety, and efficacy of venous coupler use in microsurgical anastomosis in lower limb reconstruction to provide objective appraisal of the surgical techniques.

METHODS

A systematic review (SR) and meta-analysis (MA) were performed analyzing articles from PubMed, Cochrane, Embase, and Web of Science from January 1990, to August 2018. Abstracts and titles were screened and assessed for eligibility by independent reviewers. Following full-text review, articles were included in the SR and MA. Case reports were excluded. Cochrane Collaboration and the Quality of Reporting of Meta-analyses (QUOROM) guidelines were followed.

RESULTS

Out of 15 included studies that met the inclusion criteria for the SR, 9 were included in MA. Patients treated with venous couplers did not experience more surgical complications (risk ratio (RR) 0.79; 95% confidence interval (CI) 0.48-1.33; p = .38), total failure (RR 0.61; 95% CI 0.22-1.70; p = .34), venous compromise (RR 0.72; 95% CI 0.23-2.27; p = .57), arterial compromise (RR 0.85; 95% CI 0.25-2.88; p = .80), partial failure (RR 0.77; 95% CI 0.33-1.77; p = .54), or reoperation (RR 11.79; 95% CI 0.49-286.55; p = .13) in comparison with hand-sewn anastomosis.

CONCLUSIONS

Outcomes of venous couplers in lower limb reconstruction are comparable to those of hand-sewn anastomosis. However, this study was limited by the quality of the available literature. Additional prospective studies should aim to directly compare both techniques and potential further benefits in clinical trials.

Genetic analysis of the Arabidopsis TIR1/AFB auxin receptors reveals both overlapping and specialized functions

The TIR1/AFB auxin co-receptors mediate diverse responses to the plant hormone auxin. The Arabidopsis genome encodes six TIR1/AFB proteins representing three of the four clades that were established prior to angiosperm radiation. To determine the role of these proteins in plant development we performed an extensive genetic analysis involving the generation and characterization of all possible multiply-mutant lines. We find that loss of all six TIR1/AFB proteins results in early embryo defects and eventually seed abortion, and yet a single wild-type allele of TIR1 or AFB2 is sufficient to support growth throughout development. Our analysis reveals extensive functional overlap between even the most distantly related TIR1/AFB genes except for AFB1. Surprisingly, AFB1 has a specialized function in rapid auxin-dependent inhibition of root growth and early phase of root gravitropism. This activity may be related to a difference in subcellular localization compared to the other members of the family.

Shared genetic risk contributes to type 1 and type 2 diabetes etiology

The extent to which shared genetic risk contributes to T1D and T2D etiology is unknown. In this study, we generated T1D association data of 15k samples imputed into the HRC panel which we compared to published T2D association data imputed into 1000 Genomes. The effects of genetic variants on T1D and T2D risk at known loci and genome-wide were positively correlated. Increased risk of T1D and T2D was correlated with higher fasting insulin and glucose level and decreased birth weight, among other correlations. Variants with T1D and T2D association were further enriched in pancreatic, adipose, B cell, and endoderm regulatory elements. We fine-mapped causal variants at known loci and found evidence for co-localization at five signals, four of which had same direction of effect. Shared risk variants were associated with quantitative measures of islet function and early growth, and were expression QTLs in relevant tissues. We further identified a shared variant at GLIS3 in islet accessible chromatin with allelic effects on enhancer activity. Our findings identify a shared genetic risk involving effects on islet function as well as insulin resistance, growth and development in the etiology of T1D and T2D, supporting a role for T2D-relevant processes in addition to autoimmunity in T1D risk.

The pea branching RMS2 gene encodes the PsAFB4/5 auxin receptor and is involved in an auxin-strigolactone regulation loop

Strigolactones (SLs) are well known for their role in repressing shoot branching. In pea, increased transcript levels of SL biosynthesis genes are observed in stems of highly branched SL deficient (ramosus1 (rms1) and rms5) and SL response (rms3 and rms4) mutants indicative of negative feedback control. In contrast, the highly branched rms2 mutant has reduced transcript levels of SL biosynthesis genes. Grafting studies and hormone quantification led to a model where RMS2 mediates a shoot-to-root feedback signal that regulates both SL biosynthesis gene transcript levels and xylem sap levels of cytokinin exported from roots. Here we cloned RMS2 using synteny with Medicago truncatula and demonstrated that it encodes a putative auxin receptor of the AFB4/5 clade. Phenotypes similar to rms2 were found in Arabidopsis afb4/5 mutants, including increased shoot branching, low expression of SL biosynthesis genes and high auxin levels in stems. Moreover, afb4/5 and rms2 display a specific resistance to the herbicide picloram. Yeast-two-hybrid experiments supported the hypothesis that the RMS2 protein functions as an auxin receptor. SL root feeding using hydroponics repressed auxin levels in stems and down-regulated transcript levels of auxin biosynthesis genes within one hour. This auxin down-regulation was also observed in plants treated with the polar auxin transport inhibitor NPA. Together these data suggest a homeostatic feedback loop in which auxin up-regulates SL synthesis in an RMS2-dependent manner and SL down-regulates auxin synthesis in an RMS3 and RMS4-dependent manner.

Experimental and computational simulation of total hip arthroplasty dislocation

Other than fatal pulmonary embolism and deep infection, dislocation following total hip replacement remains probably the most vexing complication to patient and surgeon. Subluxation and dislocation are complex, poorly understood phenomena. Many important questions in this area unfortunately do not lend themselves well to clinical or registry study. Appropriate realistic laboratory models have been lacking. This article synthesizes new work undertaken independently by two groups of biomechanical investigators using very different, but complimentary, methodologies to study the mechanisms of dislocation, and especially the influence of specific design and surgical variables.

Growth and function of primary rabbit kidney proximal tubule cells in glucose-free serum-free medium

The properties of primary rabbit kidney proximal tubule cells in glucose-free serum-free medium have been examined. Primary rabbit kidney proximal tubule cells were observed to grow at the same rate, 1.0 doublings/day, both in glucose-free and in glucose-supplemented medium. Growth in glucose-free medium was dependent upon the presence of an additional nutritional supplement, such as glutamine, pyruvate, palmitate, lactate, or beta hydroxybutyrate. Lactate, pyruvate, and glutamate are utilized for renal gluconeogenesis in vivo. The growth of the primary rabbit kidney proximal tubule cells in glucose-free medium was also dependent upon the presence of the three growth supplements insulin, transferrin, and hydrocortisone. Insulin was growth stimulatory to the primary proximal tubule cells in glucose-free medium, although insulin causes a reduction in the phosphoenolpyruvate carboxykinase (PEPCK) activity in these cells. PEPCK is a key regulatory enzyme in the gluconeogenic pathway. In order to evaluate whether or not the primary cells have gluconeogenic capacity, their glucose content was determined. The cells contained 5 pmoles D-glucose/mg protein. However, no significant glucose was detected in the medium. Presumably, the primary cells were either utilizing or storing the glucose made by the gluconeogenic pathway. Consistent with this latter possibility, cellular glycogen levels were observed to increase with time in culture. The effect of glucose on the expression of the alpha I(IV) collagen and laminin B1 chain genes was examined. Northern analysis indicated that the level of alpha I(IV) collagen mRNA was significantly elevated in glucose containing, as compared with glucose deficient, medium. In contrast, laminin B1 chain mRNA levels were not significantly affected by the glucose content of the medium.