Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Examining the evidence for policy and environmental strategies to prevent childhood obesity in black communities: new directions and next steps

Exposure to physical and policy environments that limit availability, affordability and appeal of healthy eating and active living options is higher for U.S. blacks than whites. This may contribute to high risk of obesity in black communities and limit effectiveness of preventive interventions. Here, we assess applicability to black Americans of findings from a prior evidence review system designed to accelerate the discovery and application of policy and environmental strategies for childhood obesity prevention and assess external validity. The database included 600 peer-reviewed articles reporting data from 396 sets of studies (study groupings) published from January 2000 through May 2009 and pertained to 24 types of policy and environmental strategies. Only 33 study groupings (~8%) included ≥ 50% black Americans or reported subgroup analyses. Of 10 evaluation studies for interventions rated as effective for all populations in the primary review, 8 suggested effectiveness of child-focused interventions in school or child care settings for obesity- or physical activity-related outcomes in black Americans. Overall findings highlight the need for rigorous evaluations of interventions that reach black children in community or institutional settings, and conceptual frameworks and research designs geared to identifying ethnic or ethnicity-income group differences in intervention effects.

Ligament balancing in computer-assisted total knee arthroplasty: improved clinical results with a spring-loaded tensioning device

Total knee arthroplasty (TKA) remains one of the most successful procedures in orthopaedic surgery. Complications certainly exist and are often related to failure of knee ligament balance. This asymmetry subsequently leads to component mal-alignment and loosening often secondary to deviation of the lower extremity mechanical axis. Understanding knee mechanics is essential, and recent technological advances have begun to minimize postoperative problems. A tensioning device that respects the native patellofemoral anatomy as well as the natural ligamentous strains has been developed. The surgical integration of computer-assisted navigation has allowed for enhanced accuracy and subsequently better results. The purpose of the current paper is to discuss the evolution of an improved ligament tensioning device, in the setting of classic mechanical guidance versus computer assistance and its postoperative impact on total knee outcomes in terms of manipulation rates and two-year radiographic alignment data. Based on a single surgeon series, mechanically guided arthroplasties resulted in a 16 per cent manipulation rate. Computer assistance with spacer blocks decreased the manipulation rate to 14 per cent, while using a novel tensioner device further decreased the manipulation rate to 7 per cent, a significant difference of p < 0.01. Radiographic data illustrate all TKAs with the tensioner to be within 4 degrees of the desired position.

Ion concentrations from hip implants

Total hip joint arthroplasty is performed in increasing numbers--about 0.16-0.2% of population per year in industrial countries. In most cases, an implant is a metallic component articulating with a metal, ceramic, or polyethylene liner, used in the hip, knee, and spine. The metal implants release ions in vivo. Toxic concentrations of ions can lead to many adverse physiological effects, including cytotoxicity, genotoxicity, carcinogenicity, and metal sensitivity. Reference levels of ion concentrations in body fluids and tissues determined by many studies are compiled, reviewed, and presented in this article. The concentrations of ions released from different alloys--including cobalt, chromium, nickel, molybdenum titanium, aluminum, and vanadium--are also presented. This article reviews the literature pertaining to clinical data on metal ion concentrations in patients with metal joint prostheses and laboratory data on the physiological effects of the metals.

Long-Term Outcomes of Stereotactic Breast Biopsies

Stereotactic core needle biopsies (SCNBs) are accurate and relatively convenient for the patient; however, the long-term follow-up of benign results has not been reported. All patients between 1993 and 1998 undergoing SCNB at a community-based hospital were entered into a registry. Follow-up was obtained by a retrospective analysis of the charts. Biopsies were performed on 865 lesions. One hundred thirty-one (15%) were malignant, 42 (5%) were suspicious for malignancy, 687 (79%) were benign, and five (1%) were lobular carcinoma in situ. Of the 42 patients with suspicious findings 38 underwent biopsy. Ten were malignant and 28 benign. Of the 687 patients with benign pathology, 377 had follow-up available with a mean length of 1.7 years. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SCNB for benign lesions in our study are all 100 per cent. Eight lesions were worrisome and await final analysis. Of 687 patients with benign lesions 310 were lost to follow-up. This study suggests that patients with a benign diagnosis should be returned to routine mammography. These data also extend the reported follow-up to 1.7 years and establish an acceptable level of accuracy for SCNB. The lost patients remind us that follow-up is essential despite a benign diagnosis.

Long-term outcomes of stereotactic breast biopsies

Stereotactic core needle biopsies (SCNBs) are accurate and relatively convenient for the patient; however, the long-term follow-up of benign results has not been reported. All patients between 1993 and 1998 undergoing SCNB at a community-based hospital were entered into a registry. Follow-up was obtained by a retrospective analysis of the charts. Biopsies were performed on 865 lesions. One hundred thirty-one (15%) were malignant, 42 (5%) were suspicious for malignancy, 687 (79%) were benign, and five (1%) were lobular carcinoma in situ. Of the 42 patients with suspicious findings 38 underwent biopsy. Ten were malignant and 28 benign. Of the 687 patients with benign pathology, 377 had follow-up available with a mean length of 1.7 years. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SCNB for benign lesions in our study are all 100 per cent. Eight lesions were worrisome and await final analysis. Of 687 patients with benign lesions 310 were lost to follow-up. This study suggests that patients with a benign diagnosis should be returned to routine mammography. These data also extend the reported follow-up to 1.7 years and establish an acceptable level of accuracy for SCNB. The lost patients remind us that follow-up is essential despite a benign diagnosis.

Walking ability in spina bifida patients: a model for predicting future ambulatory status based on sitting balance and motor level

Two-hundred six patients with spina bifida were followed from birth to an average age of 115 months. We characterized the population in terms of factors which we expected to affect walking ability. Two independent predictors of community ambulation were identified through regression analysis: sitting balance and motor level. We used these variables to develop a mathematical method to predict which groups were likely to be independent walkers into adolescence. When we tested this equation against our actual population, we correctly characterized walkers as such in 92% of the cases. Furthermore, when we applied this equation to another random population taken from our clinic, we successfully characterized walkers in 92% of the cases. The strength of these observations allows us to provide guidelines to parents about the likelihood of their children being able to walk independently as adolescents on the basis of motor level and sitting balance, which can be assessed at an early age.

The natural history of unicompartmental arthroplasty. An eight-year follow-up study with survivorship analysis

From 1983 to 1987, 82 unicondylar arthroplasties were performed for primary unicompartmental osteoarthrosis. Seven knees had lateral compartment arthroplasties and 75 had medial unicompartmental knee arthroplasties (UKA). At a minimum follow-up period of four years, eight patients had been revised, one patient was scheduled for revision, and one patient had died with a failed UKA, for a total failure rate of 12%. Reasons for failure were progression of tricompartmental arthritis in two patients (2.4%), polyethylene wear in two (2.3%), component failure in two (2.3%), component loosening in three (3.5%), and technical error in one (1.6%). Furthermore, 14 (17%) patients showed roentgenographic evidence of impending failure and an additional 12 (15%) patients showed a gradual decline in Hospital for Special Surgery knee scores. Unicondylar knee arthroplasty does not appear to provide as reliable pain relief as total knee arthroplasty. Progression to tricompartmental arthritis, polyethylene wear, and component loosening were seen to limit the usefulness of this arthroplasty. Unlike total knee arthroplasty, factors affecting the success or failure of UKA cannot be predictably controlled by the surgeon.

Myelomeningocele: a review of the orthopaedic aspects of 206 patients treated from birth with no selection criteria

Two hundred and six consecutive children with spina bifida who have been treated since the first day of life were analysed in terms of walking ability, motor level, orthopaedic deformities, operative procedures and balance deficit. The authors found that: (1) ambulation was quite delayed compared with the normal population; (2) sitting balance was a useful predictor of future walking; (3) almost all patients with quadriceps function were able to walk and were community ambulators; and (4) a significant number of congenital and acquired orthopaedic deformities required surgical intervention.

Case report 593: Hemangioma of sternum

A 38-year-old woman presented with an expansile lesion of the sternum. Plain film tomograms and computed tomography showed an expansile lesion of the sternum. Bone scanning revealed increased uptake in the sternum. The neoplasm was surgically excised and proved to be a hemangioma (Fig. 4a) and 4b). The rarity of this neoplasm in the sternum was stressed. An extensive search of the literature failed to reveal a single previous report of a sternal hemangioma. A differential list of other primary benign and malignant sternal tumors was presented.

Characterization of a 3H-arginine8-vasopressin binding site in the cingulate gyrus of the rat pup

Autoradiographic analysis of 1, 8, 16 and 26-day-old rat brains showed 3H-arginine8-vasopressin (3H-AVP) binding to the cingulate gyrus-dorsal hippocampus (CG) only in the 8-day-old rat brain. Saturation analysis of CG membranes prepared from pups (7-10 days) and adults (90 days) revealed a small but significant increase in binding site concentration in adults compared to pups. However, the Kd of the 3H-AVP binding site increased significantly with age. The Kd of 3H-AVP binding to pup CG membranes was 0.9 +/- 0.1 nM, while the adult CG was 5.7 +/- 1.0 nM. The pharmacological specificity of 3H-AVP binding sites in the pup and adult CG was similar, but differed markedly from the profile observed in adult septal membranes. The primary specificity difference between the pup CG and septum was the reduced potency of certain V1 receptor antagonists. In competition experiments the CG binding site showed a reduced affinity for the V1 antagonist, [d(CH2)5, Tyr(Me)]AVP. This reduced affinity for the V1 antagonist was also documented autoradiographically using 3H-[d(CH2)5, Tyr(Me)]AVP. The data suggest that the 3H-AVP binding site expressed in the pup CG is not identical to the V1 type receptor present in the periphery and brain of the adult rat.

Coronary artery to left atrium fistula requiring revascularisation: case report and literature review

Only 12 cases of coronary artery to left atrium fistula have been reported, with successful correction in at least seven. We describe a unique case of repair of a left main coronary artery to left atrium fistula using revascularisation with general discussion of the embryology, pathophysiology, complications, and diagnosis of these fistulae, indications for operation, and guidelines for surgical management.

Two-dimensional echocardiograms of a transvenous left ventricular pacing catheter

A permanent transvenous pacemaker lead was placed across the atrial septum and retained in the left ventricle for eight years. M-mode echocardiograms showed a linear echocardiographic density in the left atrium and mitral valve. Cross-sectional echocardiograms further defined the location and course of the pacing lead.

Effect of intra-aortic balloon pumping on nutrient coronary flow in normal and ischemic myocardium

The effects of intra-aortic balloon pumping (IABP) on myocardial flow distribution were studied in 50 dogs. Cardiac output was controlled by right heart bypass. In each dog the following parameters were measured with and without IABP during normal coronary perfusion and after regional ischemia was induced by anterior descending coronary vein flow by timed collection, and endocardial/epicardial flow ratios by a previously reported thermal washout technique. In nonischemic myocardium, IABP significantly (p less than 0.05) increased mean coronary sinus flow 11.5 percent +/- 5.8 percent (S.D.) and the mean endocardial/epicardial ratio, 17.3 percent +/- 0.28 percent. In the regionally ischemic myocardium, IABP significantly (p less than 0.05) increased mean segmental coronary vein flow 13.9 percent +/- 1.23 percent but decreased the endocardial/epicardial ratio 29.9 percent +/- 1.1 percent. We conclude that in the dog, IABP enhances subendocardial blood flow in perfused but not in ischemic myocardium. Contrary to common suppositions, the increase in collateral blood flow with IABP preferentially supplies epicardial layers in segmental ischemic zones, but may be shunted from the subendocardium.

Large intercostal arteriovenous aneurysm: successful surgical correction

A large aberrant systemic artery to superior vena cava communication associated with normal lungs and normal pulmonary arteries has never been reported. This lesion, its diagnosis, and successful surgical management are discussed.