Citations

Background— Several echocardiographic dyssynchrony indexes have been proposed to identify responders to cardiac resynchronization therapy using tissue velocity and strain. The present study aimed to compare tissue velocity–derived and strain-derived dyssynchrony indexes in patients with or without systolic dysfunction and left bundle-branch block. Methods and Results— Tissue Doppler imaging was performed in 120 subjects divided into 4 groups: group 1 (n=40), normal subjects; group 2 (n=20), normal left ventricular ejection fraction and left bundle-branch block; group 3 (n=20), left ventricular ejection fraction <35% and normal conduction; and group 4 (n=40), left ventricular ejection fraction <35% and left bundle-branch block. Dyssynchrony indexes based on time to peak tissue velocity (septal-lateral delay, anteroseptal-posterior delay, and SD in time to peak systolic velocity in the 12 left ventricular segments) and strain (SD of time to peak strain in 12 segments) were measured. The SD in time to peak systolic velocity in the 12 left ventricular segments was greater in group 4 (54 ms; 25th and 75th percentiles, 46 to 64 ms) than group 1 (44 ms; 25th and 75th percentiles, 28 to 53 ms; P =0.006), but there was a considerable overlap of all tissue velocity–derived indexes among 4 groups, with 40% to 68% of group 1 having values proposed for predicting the responders of cardiac resynchronization therapy. The SD of time to peak strain in 12 segments distinguished these groups with much less overlap ( P <0.01 for all pairwise comparisons). Conclusions— A substantial proportion of normal subjects have tissue velocity–derived dyssynchrony indexes higher than the cutoff value proposed for predicting beneficial effect of cardiac resynchronization therapy. Strain-derived timing index appears to be more specific for dyssynchrony in patients with systolic dysfunction and left bundle-branch block. Identifying an optimal tissue velocity– or strain-derived dyssynchrony index requires a large prospective clinical trial.

ABSTRACTWe evaluated the participatory role of human HLA-DR molecules in control of virus from the central nervous system and in the development of subsequent spinal cord demyelination. The experiments utilized intracranial infection with Theiler's murine encephalomyelitis virus (TMEV), a picornavirus that, in some strains of mice, results in primary demyelination. We studied DR2 and DR3 transgenic mice that were bred onto a combined class I-deficient mouse (beta-2 microglobulin deficient; β2m0) and class II-deficient mouse (Aβ0) of theH-2bbackground. Aβ0.β2m0mice infected with TMEV died within 18 days of infection. These mice showed severe encephalomyelitis due to rapid replication of virus genome. In contrast, transgenic mice with insertion of a single human class II major histocompatibility complex (MHC) gene (DR2 or DR3) survived the acute infection. DR2 and DR3 mice controlled virus infection by 45 days and did not develop spinal cord demyelination. Levels of virus RNA were reduced in HLA-DR transgenic mice compared to Aβ0.β2m0mice. Virus-neutralizing antibody responses did not explain why DR mice survived the infection and controlled virus replication. However, DR mice showed an increase in gamma interferon and interleukin-2 transcripts in the brain, which were associated with protection. The findings support the hypothesis that the expression of a single human class II MHC molecule can, by itself, influence the control of an intracerebral pathogen in a host without a competent class I MHC immune response. The mechanism of protection appears to be the result of cytokines released by CD4+T cells.

AbstractBackgroundCushing’s syndrome (CS), due to multiple etiologies, is a disorder associated with the ravages of cortisol excess. The purpose of this review article is to provide a historical synopsis of surgery for CS, review a recent 10‐year period of operative management at a tertiary care facility, and to outline a practical approach to diagnosis and management.Materials and MethodsFrom 1996 to 2005, 298 patients underwent 322 operative procedures for CS at Mayo Clinic, Rochester, Minnesota. A retrospective chart review was carried out. Data was gathered regarding demographics, preoperative assessment, procedures performed, and outcomes. Data are presented as counts and percentages. Five‐year survival rates were calculated where applicable by the Kaplan‐Meier method. Statistical analysis was carried out with SAS, version 9 (SAS Institute, Inc., Cary, NC).ResultsTwo‐hundred thirty‐one patients (78%) had ACTH‐dependent CS and 67 patients (22%) had ACTH‐independent CS. One‐hundred ninety‐six patients (66%) had pituitary‐dependent CS and 35 patients (12%) had ectopic ACTH syndrome. Fifty‐four patients (18%) had cortisol‐secreting adenomas, 10 patients (3%) had cortisol‐producing adrenocortical carcinomas, and 1% had other causes. Cure rates for first time pituitary operations (transsphenoidal, sublabial, and endonasal) were 80% and 55% for reoperations. Most benign adrenal processes could be managed laparoscopically. Five‐year survival rates (all causes) were 90%, 51%, and 23% for adrenocortical adenomas, ectopic ACTH syndrome, and adrenocortical carcinomas, respectively.ConclusionsSurgery for CS is highly successful for pituitary‐dependent CS and most ACTH‐independent adrenal causes. Bilateral total adrenalectomy can also provide effective palliation from the ravages of hypercortisolism in patients with ectopic ACTH syndrome and for those who have failed transsphenoidal surgery. Unfortunately, to date, adrenocortical carcinomas are rarely cured. Future successes with this disease will likely depend on a better understanding of tumor biology, more effective adjuvant therapies and earlier detection. Clearly, IPSS, advances in cross‐sectional imaging, along with developments in transsphenoidal and laparoscopic surgery, have had the greatest impact on today’s management of the complex patient with CS.

Abstract Background Management of patients with bilateral adrenal masses and corticotropin (ACTH)‐independent Cushing syndrome (CS) or subclinical CS is problematic. We report our experience with adrenal venous sampling (AVS) in the evaluation of 10 patients with bilateral masses who had ACTH‐independent CS or subclinical CS. Patients and Methods Ten patients (9 women, 1 man, mean age 56.4 years) with bilateral adrenal masses and ACTH‐independent CS ( n = 3) or subclinical CS ( n = 7) underwent AVS. Autonomous cortisol secretion was documented in all cases with suppressed serum ACTH concentrations and lack of cortisol suppression with dexamethasone administration. Adrenal venous sampling was performed on the second day of dexamethasone administration. Cortisol and epinephrine levels were measured from each adrenal vein (AV) and from a peripheral vein (PV). Results Mean (± SD) maximal diameter of the adrenal masses on computed tomography was 3.3 ± 1.3 cm (range: 1.2–6.0 cm). Successful catheterization was confirmed with AV:PV epinephrine gradients. A cortisol AV:PV gradient >6.5 was consistent with a cortisol‐secreting adenoma in 11 adrenal glands; 5 patients had clinically important bilateral autonomous cortisol hypersecretion, 3 had bilateral cortisol‐secreting adenomas, and 2 had ACTH‐independent macronodular adrenal hyperplasia. Adrenal venous sampling‐guided adrenalectomy was completed in all 10 patients—2 patients had total bilateral adrenalectomy and 2 others had subtotal bilateral adrenalectomy. During a mean follow‐up of 36.1 months (range: 0.7–123 months), CS or clinically important cortisol secretory autonomy did not recur. Conclusions Adrenal venous sampling contributed to the localization of autonomous hypercortisolism in the setting of ACTH‐independent CS or subclinical CS in patients with bilateral adrenal masses.

Questions remain as to whether pediatric sleep disordered breathing increases the risk for elevated blood pressure and blood pressure–dependent cardiac remodeling. We tested the hypothesis that activity-adjusted morning blood pressure surge, blood pressure load, and diurnal and nocturnal blood pressure are significantly higher in children with sleep disordered breathing than in healthy controls and that these blood pressure parameters relate to left ventricular remodeling. 24-hour ambulatory blood pressure parameters were compared between groups. The associations between blood pressure and left ventricular relative wall thickness and mass were measured. 140 children met the inclusion criteria. In children with apnea hypopnea index <5 per hour, a significant difference from controls was the morning blood surge. Significant increases in blood pressure surge, blood pressure load, and in 24-hour ambulatory blood pressure were evident in those whom the apnea hypopnea index exceeded 5 per hour. Sleep disordered breathing and body mass index had similar effect on blood pressure parameters except for nocturnal diastolic blood pressure, where sleep disordered breathing had a significantly greater effect than body mass index. Diurnal and nocturnal systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure predicted the changes in left ventricular relative wall thickness. Therefore, sleep disordered breathing in children who are otherwise healthy is independently associated with an increase in morning blood pressure surge, blood pressure load, and 24-hour ambulatory blood pressure. The association between left ventricular remodeling and 24-hour blood pressure highlights the role of sleep disordered breathing in increasing cardiovascular morbidity.