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.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Interpretation of Post-operative Distal Humerus Radiographs After Internal Fixation: Prediction of Later Loss of Fixation

PURPOSE

Stable fixation of distal humerus fracture fragments is necessary for adequate healing and maintenance of reduction. The purpose of this study was to measure the reliability and accuracy of interpretation of postoperative radiographs to predict which implants will loosen or break after operative treatment of bicolumnar distal humerus fractures. We also addressed agreement among surgeons regarding which fracture fixation will loosen or break and the influence of years in independent practice, location of practice, and so forth.

METHODS

A total of 232 orthopedic residents and surgeons from around the world evaluated 24 anteroposterior and lateral radiographs of distal humerus fractures on a Web-based platform to predict which implants would loosen or break. Agreement among observers was measured using the multi-rater kappa measure.

RESULTS

The sensitivity of prediction of failure of fixation of distal humerus fracture on radiographs was 63%, specificity was 53%, positive predictive value was 36%, the negative predictive value was 78%, and accuracy was 56%. There was fair interobserver agreement (κ = 0.27) regarding predictions of failure of fixation of distal humerus fracture on radiographs. Interobserver variability did not change when assessed for the various subgroups.

CONCLUSIONS

When experienced and skilled surgeons perform fixation of type C distal humerus fracture, the immediate postoperative radiograph is not predictive of fixation failure. Reoperation based on the probability of failure might not be advisable.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Not so bad after all: retroviruses and long terminal repeat retrotransposons as a source of new genes in vertebrates

Viruses and transposable elements, once considered as purely junk and selfish sequences, have repeatedly been used as a source of novel protein-coding genes during the evolution of most eukaryotic lineages, a phenomenon called 'molecular domestication'. This is exemplified perfectly in mammals and other vertebrates, where many genes derived from long terminal repeat (LTR) retroelements (retroviruses and LTR retrotransposons) have been identified through comparative genomics and functional analyses. In particular, genes derived from gag structural protein and envelope (env) genes, as well as from the integrase-coding and protease-coding sequences, have been identified in humans and other vertebrates. Retroelement-derived genes are involved in many important biological processes including placenta formation, cognitive functions in the brain and immunity against retroelements, as well as in cell proliferation, apoptosis and cancer. These observations support an important role of retroelement-derived genes in the evolution and diversification of the vertebrate lineage.

Therapeutically interchangeable? A study of real-world outcomes associated with switching basal insulin analogues among US patients with type 2 diabetes mellitus using electronic medical records data

AIMS

To evaluate real-world clinical outcomes for switching basal insulin analogues [insulin glargine (GLA) and insulin detemir (DET)] among US patients with type 2 diabetes mellitus (T2DM).

METHODS

Using the GE Centricity Electronic Medical Records database, this retrospective study examined two cohorts: cohort 1, comprising patients previously on GLA and then either switching to DET (DET-S) or continuing with GLA (GLA-C); and cohort 2, comprising patients previously on DET and then either switching to GLA (GLA-S) or continuing with DET (DET-C). Within each cohort, treatment groups were propensity-score-matched on baseline characteristics. At 1-year follow-up, insulin treatment patterns, glycated haemoglobin (HbA1c) levels, hypoglycaemic events, weight and body mass index (BMI) were evaluated.

RESULTS

The analysis included 13 942 patients: cohort 1: n = 10 657 (DET-S, n = 1797 matched to GLA-C, n = 8860) and cohort 2: n = 3285 (GLA-S, n = 858 matched to DET-C, n = 2427). Baseline characteristics were similar between the treatment groups in each cohort. At 1-year follow-up, in cohort 1, patients in the DET-S subgroup were significantly less persistent with treatment, more likely to use a rapid-acting insulin analogue, had higher HbA1c values, lower HbA1c reductions and lower proportions of patients achieving HbA1c <7.0 or <8.0% compared with patients in the GLA-C subgroup, while hypoglycaemia rates and BMI/weight values and change from baseline were similar in the two subgroups. In cohort 2, overall, there were contrasting findings between patients in the GLA-S and those in the DET-C subgroup.

CONCLUSIONS

This study showed contrasting results when patients with T2DM switched between basal insulin analogues, although these preliminary results may be subject to limitations in the analysis. Nevertheless, this study calls into question the therapeutic interchangeability of GLA and DET, and this merits further investigation.

A brief review of potential mechanisms of immune reconstitution inflammatory syndrome in HIV following antiretroviral therapy

A subset of HIV-infected individuals who receive antiretroviral therapy (ART) develop a paradoxical pathological response that significantly increases morbidity and sometimes mortality. Following the induction of highly active ART, a rapid decline in the viral load results within weeks and coincides with a steep rise in the CD4(+) T-cell counts and immune hyperactivation. Although no mechanistic pathway has been elucidated for the development of immune reconstitution inflammatory syndrome (IRIS), it is thought that change in the nature of the immune response is a predominant factor in the development of reconstitution disease. In this article, we review the current state of knowledge in this field and provide a model for the development of IRIS.

The cost-effectiveness of insulin glargine vs. neutral protamine Hagedorn insulin in type 2 diabetes: a focus on health economics

Diabetes mellitus is a major public health problem, in particular because of long-term complications affecting essential organs, such as the eyes and kidneys, which can lead to a reduction in life expectancy and high healthcare costs. The number of individuals with diabetes mellitus is projected to rise worldwide from 171 million people in 2000 to 366 million people in 2030. With the number of patients with diabetes continually growing, the burden of pressure on worldwide health systems is huge. Accordingly, regulatory and marketing approvals of new medicines are beginning to incorporate economic evaluation techniques to determine their cost-effectiveness. Overall, the studies included in this review show that the initiation of insulin glargine is cost-effective and is expected to lead to substantial improvements in both life years (LYs) and quality-adjusted LYs compared with neutral protamine Hagedorn insulin.

Injury toll following the 1997 Maccabiah Games bridge collapse: implications of major disasters for sports medicine teams

A major disaster was encountered at the 1997 Maccabiah Games in Israel. As the Australian team was about to enter the main stadium for the opening ceremony, a pedestrian bridge they were crossing collapsed, killing 4 athletes and injuring many others. The aim of this paper is to establish the rates, types and anatomical locations of musculoskeletal injuries incurred by members of the Australian Maccabiah Games team, with particular reference to the impact of the bridge collapse. In total, the 410 members of the team (360 athletes and coaches and 50 team officials) reported 166 injuries from their participation in sport and 30 musculoskeletal injuries associated with the collapse of the bridge. The most common sports-related injuries were sprains and strains to the hip/thigh, lumbar spine and ankle/foot regions, while the bridge collapse resulted in, most commonly, sprains and contusions to the hip/thigh, knee, lower leg and ankle/foot regions. In addition, team members incurred many medical and psychological conditions. This paper makes several recommendations for sports medicine staff based on the experience of this significant sport disaster.

What psychological testing and neuroimaging tell us about the treatment of Posttraumatic Stress Disorder by Eye Movement Desensitization and Reprocessing

To better understand the pathophysiology and treatment of Posttraumatic Stress Disorder (PTSD), standard psychological testing, Rorschach Ink Blot testing, and neuroimaging using Single Photon Emission Computed Tomography (SPECT) were administered to subjects with PTSD prior to and following three sessions of Eye Movement Desensitization and Reprocessing (EMDR). Using this within-subject design, data from one of six subjects in our series is presented as a case report. Following EMDR, the subject experienced improvement in his level of distress, which correlated with decrements in PTSD and depressive symptomatology on psychological testing. Analysis of the Rorschach data corroborated these changes. Among other findings, the Hypervigilance Index went from positive to negative, indicating that the subject was spending less time scanning the environment for threats, and available ego resources also increased, as measured by the Experience Actual variable. Upon recall of the traumatic memory during SPECT scanning, two areas of the brain were hyperactive post-EMDR treatment relative to pretreatment: the anterior cingulate gyrus and the left frontal lobe. These changes were consistent with summed data from four out of six subjects in the ongoing study. An important implication of these findings is that successful treatment of PTSD does not reduce arousal at the limbic level, but instead, enhances the ability to differentiate real from imagined threat. The psychology and neurophysiology of PTSD are discussed in greater detail.

Hospital and catchment area antibiotic utilization and bacterial sensitivity in primary infections following gastric surgery in Huddinge, Sweden

The relationship between hospital and catchment area utilization of antimicrobial agents and the antibiotic sensitivity of bacteria isolated from primary infections has been studied after 750 gastric operations performed between 1972 and 1986 at the Huddinge University Hospital. Over 80% of the antibiotics were used in the catchment area. Penicillins (G and V) overall were the most commonly used drugs and comprised 37% of the total antibiotic consumption in 1977-1986. Narrow-spectrum antibiotics dominated throughout the period under investigation. No change in the bacterial resistance to antimicrobial agents was found over time. Many strains of Klebsiella/Enterobacter and E. coli resistant to ampicillin and tetracyclines were recovered throughout the period under investigation. No aerobic Gram-negative bacteria were resistant to gentamicin. All Bacteroides strains except two were sensitive to cefoxitin. Tetracyclines and ampicillin/amoxycillin were mainly used in the catchment area, and cefoxitin and aminoglycosides were almost exclusively used in the hospital. Antimicrobial agents primarily used for out-patients in the catchment area seemed to have more influence on the susceptibility of microorganisms isolated from post-operative infections than agents primarily used in the hospital.

Postoperative hospital retention following ambulatory surgery in a hospital-based program

In an effort to learn more about resource utilization on ambulatory surgery in hospital departments of surgery and its impact on quality of care, we reviewed the causes of postoperative hospital retention following ambulatory surgery in a hospital-based program. Of 1971 patients operated on in a 6-month period, 188 were retained for a rate of 9.5%. Of these, 71 (3.6%) were retained for observation and 42 (2.1%) for surgery more extensive than planned. The remaining 75 (3.8%) patients represent complications of surgery or anesthesia. The age distribution of patients with complications was the same as the group overall with a single mode at about 30 years, while the distribution of patients retained for observation or who were admitted the day of surgery was bimodal with a second peak at about 70 years. All surgical specialties had comparable rates of postoperative retention, except gynecology which was significantly lower. Many of the patients had multiple procedures or surgery more extensive than planned.

The causes of cancelled elective surgery

We reviewed causes of cancelled elective surgery in a community hospital. Over a 6-month period, during which 4100 operating room procedures were completed, cancellations occurred in 13% of cases scheduled for outpatient surgery, 9% of cases scheduled for admission the same day, and 17% of cases scheduled for inpatient surgery. Dental procedures had significantly higher rates of cancellation among outpatient procedures, and cardiovascular surgical procedures had significantly higher rates among inpatient procedures. Chart review of cancelled inpatient cases showed 43% due to administrative reasons with unsigned consent the most common cause. Medical factors were responsible in the remaining cases, with reevaluation of the surgical condition and associated medical illnesses equally common as reasons in this category. Appreciation of the usual reasons for cancellation can improve utilization by permitting administrators and providers to anticipate those cases in which problems might arise so that additional attention can be paid to them.

Septic complications in relation to factors influencing the gastric microflora in patients undergoing gastric surgery

Postoperative septic complications and micro-organisms found in primary infections were studied in 750 gastric operations performed between 1972 and 1986. The overall rate of primary infections was 23%. The infection rates were related to the diagnosis and to factors that could influence the colonization of the stomach. No significant differences in the rates of postoperative infections were found between patients who had received preoperative antibiotic prophylaxis and those who had not. In all groups of patients, aerobic and anaerobic gram-positive and gram-negative bacteria and yeasts were isolated in primary infections. Enterobacteriaceae, enterococci and Bacteroides fragiis were more frequent in patients with gastric bleeding or carcinoma.

Intraoperative decisions based on angioscopy in peripheral vascular surgery

We describe the technique of intraoperative angioscopy for delineation of peripheral vascular anatomy. Angioscopes with outer diameters of 0.85-2.9 mm have been used during 86 peripheral vascular procedures. Angioscopic inspections were performed during 68 femoral popliteal bypasses, four aortofemoral bypass grafts, one abdominal aortic aneurysm, two extra anatomic axillary femoral bypass grafts, and 11 other vascular procedures. We obtained useful images in 73 of 86 procedures (85%), thereby yielding 118 angioscopic inspections (53 arteries, 37 anastomoses, and 28 vein grafts). Changes in intraoperative management based on angioscopic findings included revision of five of 37 (14%) anastomoses, deletion of four of 31 (13%) completion angiograms, revision of eight of 17 (47%) in situ venous valves, and repetition of thrombectomy in six of seven (86%) cases. In 22 of 73 (30%) peripheral angioscopies, potential causes of graft occlusion were recognized. Complications from intraoperative angioscopy have included one anastomotic flap from intimal disruption that required anastomotic revision. Three small flaps, possibly resulting from angioscopic trauma, were recognized but appeared to have no clinical significance. In conclusion, intraoperative angioscopy provides visual assessment of luminal patency and anastomotic anatomy. This assessment alters intraoperative procedures in some cases and cannot be obtained by angiography.

Estrogen-secreting adrenal tumor responsive to ACTH: localization by adrenal venous sampling

In a 48-year-old man with gynecomastia but no other signs of feminization, routine evaluation revealed only minimally elevated serum estrogens. The diagnosis of an estrogen-secreting adrenal tumor was suggested by CT and confirmed by adrenal venous sampling. This tumor was found to be ACTH-responsive. Results in this patient are compared with those in normal volunteers, in whom adrenal venous sampling failed to localize estrogen secretion and in whom ACTH did not increase estrogens.

Glucose metabolism in glucose-intolerant older people during chromium supplementation

The effects of chromic chloride (CrCl3) administered orally for 12 weeks to five elderly subjects with glucose intolerance were assessed. Pretreatment and posttreatment, the hyperglycemic clamp technique was employed to determine glucose utilization, beta-cell sensitivity to glucose, and tissue sensitivity to insulin. In addition, erythrocyte insulin binding was studied. Urinary chromium excretion increased approximately 5 fold indicating good compliance with supplementation. The oral glucose tolerance curves following supplementation were lowered from 60 to 120 minutes but only the 60-minute values were significantly lowered. In agreement with this was significantly increased glucose utilization during the hyperglycemic clamp studies. Tissue sensitivity to insulin, receptor affinity, and total insulin binding were unchanged by supplementation while beta-cell sensitivity to glucose increased following supplementation (P less than 0.04), and explained the increased glucose utilization. HDL and LDL and total cholesterol levels were slightly lower after chromium supplementation, but no change reached statistical significance. The LDL/HDL cholesterol ratio was unchanged. This study shows small but statistically significant effects of CrCl3 on carbohydrate metabolism. The clinical relevance of these effects, that is, their prophylactic or therapeutic significance, remains to be determined.

The diagnostic value of the 24 hour integrated concentration of plasma aldosterone

The 24-hour urinary excretion rate of aldosterone, the 24-hour integrated concentration of plasma aldosterone (IC-ALDO) and the morning plasma aldosterone levels from a single, discrete venipuncture of 92 subjects (30 normal subjects, 62 patients with mild, essential hypertension) were compared, using the variance ratio method, to 12 patients with primary aldosteronism. The variance of the IC-ALDO was significantly lower than the respective variances of the 24-hour urinary excretion of aldosterone (P less than 0.01) and of the discrete, morning plasma levels of aldosterone (P less than 0.01). The clinical usefulness of this diagnostic procedure depends on its ability to discriminate between healthy subjects and various hypertensive patients. Because of its narrower variance and enhanced discriminatory ability, the 24-hour IC-ALDO may have useful application in diagnosis of various disorders of aldosterone secretion. We have found the IC-ALDO completely separated 11 of 12 primary aldosteronism patients (mean 36 +/- 17) from essential hypertensive controls (mean 9.6 +/- 4.1) (P less than 0.01). When IC-ALDO was combined with integrated concentration of plasma renin activity in an ALDO/RENIN ratio, all 12 primary aldosteronism patients were diagnosed.

Limitations in usefulness of single dose intermediate acting insulin: a rapid response pattern in some type I diabetics

Ten Type I insulin-dependent diabetics who were receiving single daily injections of intermediate acting insulin were studied to assess time-response characteristics of this therapy on 24-hour profiles of both glucose and free insulin. Nine of ten patients had undetectable postprandial levels of C-peptide. All patients had insulin antibodies typical of chronically treated Type I diabetes. Mean peak free insulin levels occurred four hours post injection with free insulin rising from 12.3 +/- 1.6 microU/ml to 26.5 +/- 1.4 microU/ml; p less than 0.01. The glucose nadir for the 24-hour profile also occurred at four hours after injection with glucose declining from 199 +/- 29 mg/dl fasting to 155 +/- 5 mg/dl; p less than 0.05. There was significant negative correlation between mean glucose and free insulin throughout the first six hours after insulin injection (r = -0.74; p less than 0.02); no correlation occurred 8 to 12 hours post injection. Two of the ten patients had hypoglycemic symptoms within four hours after their morning insulin. Although free insulin levels remained above basal for 20 hours, single dose intermediate insulin therapy never really controlled postprandial glucose levels after breakfast or lunch. These data suggest there may be limitations in managing Type I diabetics with single dose intermediate insulin. Furthermore, some patients on intermediate acting insulin may have a more rapid than anticipated maximal hypoglycemic response, often within four hours.

Hemodynamic monitoring of patients undergoing abdominal aortic surgery

Cardiac decompensation is clearly the major complication of aortic reconstructive surgery that leads to morbidity. Major changes in intravascular volume, third spacing, and increased systemic vascular resistance are extremely stressful to the diseased heart. Hemodynamic monitoring is readily available to provide an accurate evaluation of myocardial sensitivity and to allow for appropriate pharmacologic manipulation to preclude cardiac catastrophe. We believe all patients undergoing abdominal aortic reconstructive surgery should receive the benefit of pulmonary artery catheterization and intraarterial monitoring. The only requirement is a staff of surgeons, anesthesiologists, and nurses capable of correct interpretation of the data and use of drug therapy based on this information. The benefits are an accurate assessment of cardiac function with the ability to modulate the patient's hemodynamic values, preventing volume shifts, hypertensive and hypotensive crises, and abnormal fluctuations in preload and afterload, and ultimately a safer perioperative course.

Effect of aging on prolactin regulation of rat striatal dopamine receptor concentrations

Administration of highly purified rat prolactin by miniosmotic pump increases striatal dopamine receptor concentrations in both mature (4-6 months) and senescent (24 months) male Wistar rats. Although receptor levels in untreated rats are about 30% lower in the senescent group, elevated levels following prolactin are not significantly different between ages. Increases in circulating prolactin levels after 7 days of treatment were not detectable at the low concentrations used (150 ng/hr). In fact, there was a trend toward decreases in circulating prolactin concentrations to the same level in both groups after treatment, despite substantially elevated basal levels in many of the senescent rats.

Dietary restriction retards the age-associated loss of rat striatal dopaminergic receptors

In male Wistar rats subjected to dietary restriction by alternate days of feeding and fasting the normal age-associated loss of striatal dopamine receptors in the brain was substantially retarded. The mean survival time of the rats on the restricted diet was increased by approximately 40 percent compared to control rats given free access to food. Dopamine receptor concentrations in striata of 24-month-old rats that had been on a restricted diet since weaning were 50 percent higher than those of control animals of the same age, and essentially comparable to 3- and 6-month-old control rats.