Pulmonary Valve Opening With Two Rotary Left Ventricular Assist Devices for Biventricular Support

Right ventricular failure is a common complication associated with rotary left ventricular assist device (LVAD) support. Currently, there is no clinically approved long‐term rotary right ventricular assist device (RVAD). Instead, clinicians have implanted a second rotary LVAD as RVAD in biventricular support. To prevent pulmonary hypertension, the RVAD must be operated by either reducing pump speed or banding the outflow graft. These modes differ in hydraulic performance, which may affect the pulmonary valve opening (PVO) and subsequently cause fusion, valvular insufficiency, and thrombus formation. This study aimed to compare PVO with the RVAD operated at reduced speed or with a banded outflow graft. Baseline conditions of systemic normal, hypo, and hypertension with severe biventricular failure were simulated in a mock circulation loop. Biventricular support was provided with two rotary VentrAssist LVADs with cardiac output restored to 5 L/min in banded outflow and reduced speed conditions, and systemic and pulmonary vascular resistances (PVR) were manipulated to determine the range of conditions that allowed PVO without causing left ventricular suction. Finally, RVAD sine wave speed modulation (±550 rpm) strategies (co‐ and counter‐pulsation) were implemented to observe the effect on PVO. For each condition, outflow banding had higher PVR (97 ± 20 dyne/s/cm⁵ higher) for when the pulmonary valve closed compared to reduced speed. In addition, counter‐pulsation demonstrated greater PVO than co‐pulsation and constant speed. For the purpose of reducing the risks of pulmonary valve insufficiency, fusion, and thrombotic event, this study recommends a RVAD with a steeper H‐Q gradient by banding and further exploration of RVAD speed modulation.     

Exogenous lung surfactant: effect on radiographic appearance in premature infants

At birth, premature infants of 25-29 weeks gestation, at high risk for development of neonatal respiratory distress syndrome (RDS), were given a single dose (90 mg) of calf lung surfactant extract (CLSE) by intratracheal instillation. The frequency and severity of RDS were assessed with use of a simple radiographic scoring system in which pulmonary parenchymal densities and the prominence of the air-bronchogram effect were used as indicators of widespread atelectasis. Radiographs were obtained in surfactant-treated and control infants within the first 90 minutes of life as part of an initial evaluation of their pulmonary status. Subsequent examinations were performed at less than 24 hours and less than 48 hours of age. Radiographic assessment of lung disease compared consistently with coordinated data on oxygen and mean airway pressure requirements of the infants. Both indicated a significantly decreased frequency and severity of RDS in the infants treated with surfactant. The results provide supporting evidence of the effectiveness of exogenous lung surfactant replacement in mitigating RDS in very premature infants.     

Thrombosis at venous insertion sites after inferior vena caval filter placement

Color Doppler flow imaging or compression ultrasound (US) was used to prospectively determine frequency of thrombosis at 54 venous insertion sites (47 in common femoral veins, seven in right internal jugular veins) after percutaneous placement of Greenfield filters for interruption of the inferior vena cava. Fifty-one filters were successfully placed in 51 patients with a dilator set or a balloon angioplasty catheter. Nine focal thrombi were detected in the common femoral vein (19%) and one in the right internal jugular vein (14%). Use of dilators induced eight thrombi (24%), compared with two (10%) from balloon catheters. The left common femoral vein had a high frequency of thrombosis, regardless of dilation technique (five of nine). Of nine patients with acute common femoral vein thrombosis, four became symptomatic within 10 days after the procedure. Patients may remain asymptomatic or have delayed symptoms; thus, US is valuable for determining patients at risk of thrombosis of the common femoral vein.     

The genetics of reading disability

Genetic factors contribute substantially to the development of reading disability (RD). Family linkage studies have implicated many chromosomal regions containing RD susceptibility genes, of which putative loci at 1p34–p36 (DYX8), 2p (DYX3), 6p21.3 (DYX2), and 15q21 (DYX1) have been frequently replicated, whereas those at 3p12–q12 (DYX5), 6q13–q16 (DYX4), 11p15 (DYX7), 18p11 (DYX6), and Xq27 (DYX9) have less evidence. Association studies of positional candidate genes have implicated DCDC2 and KIAA0319 in DYX2, as well as C2ORF3 and MRPL19 (DYX3), whereas DYX1C1/EKN1 (DYX1) and ROBO1 (DYX5) were found to be disrupted by rare translocation breakpoints in reading-disabled individuals. Four of the candidate genes (DYX1C1, KIAA0319, DCDC2, and ROBO1) appear to function in neuronal migration and guidance, suggesting the importance of early neurodevelopmental processes in RD. Future studies to help us understand the function of these and other RD candidate genes promise to yield enormous insight into the neurobiologic mechanisms underlying the pathophysiology of this disorder.     

The occurrence of fever during hemodialysis and hemofiltration. A comparative study

The occurrence of fever during various blood purification methods was evaluated in a retrospective study. It could be demonstrated, that patients treated chronically by conventional hemodialysis experience six times more febrile episodes than patients on chronic hemofiltration (4.84% versus 0.81%). Since many of the increased temperatures could not be explained by conventional means, it has to be assumed that the treatment itself caused the fever, possibly activating the monocyte hormone interleukin 1. It is of further note that there was no difference in the magnitude of the temperature due to septicaemia or to no obvious cause. This finding necessitates in our opinion an early antibiotic therapy in those cases where fever develops without clear explanation.     

Hypercalcemia and elevated serum 1,25-dihydroxyvitamin D3 in a patient with hodgkin's lymphoma

Summary A 74-year-old woman was hospitalized because of decreased appetite, fatigue, and weight loss. The laboratory examination revealed hypercalcemia, a slightly increased serum creatinine level, and a markedly elevated serum level of 1,25-dihydroxyvitamin D₃. The most important finding the physical examination revealed was enlarged inguinal lymph nodes. A biopsy disclosed lymphocyte-depleted Hodgkin's disease. After steroids, but not after calcitonin, both the elevated calcitriol concentration and serum calcium normalized. In spite of intensive chemotherapy, a further episode with hypercalcemia occurred and increased 1,25-dihydroxyvitamin D₃ serum levels were observed. According to the available evidence it seems probable that the humoral hypercalcemia in this patient resulted from production of 1,25-dihydroxyvitamin D₃ in the tumor.Abbreviations 1,25(OH)₂D₃ 1,25-dihydroxyvitamin D₃ - iPTH serum immunoreactive parathyroid hormone     

Segregation and linkage analyses of Tourette's syndrome and related disorders

Segregation and linkage analyses were performed with data from a large Tourette's syndrome (TS) multigenerational kindred. Results of segregation analyses were remarkably similar to some reported earlier and suggest that the mode of transmission is consistent with autosomal dominant inheritance. The analyses were done using three diagnostic schemes to specify affected family members (TS only; TS or chronic tics [CT]; and TS, CT or obsessive compulsive disorder [OCD]). The estimates of penetrance for the genotypes AA, Aa and aa (A denotes the susceptibility allele) in the analyses including relatives with TS, CT or OCD were 0.99, 0.99 and 0.00, respectively, for males and 0.70, 0.70 and 0.00 for females. Pairwise linkage analyses with 140 marker loci failed to identify a linked marker. However, approximately 30 percent of the genome was excluded as the site of the hypothesized locus for TS.     

Pulmonary histiocytosis X: comparison of radiographic and CT findings

The authors retrospectively evaluated radiographs, computed tomographic (CT) scans, and results of pulmonary function tests (when available) for 17 patients with biopsy-proved pulmonary histiocytosis X. In 11 patients, high-resolution CT was used. In 12 patients, CT demonstrated cystic air spaces, usually less than 10 mm in diameter. In three of these 12, cysts were the only abnormality, but in six others, nodules (usually less than 5 mm in diameter) were also present. Two patients had only nodules and one, only emphysema. CT showed that many lesions that appeared reticular on plain radiographs were actually cysts. CT showed no central or peripheral concentration of lesions, but it did reveal that many small nodules were distributed in the centers of secondary lobules around small airways. CT findings correlated better with the diffusing capacity (rho = -0.71) than did the plain radiographic findings (rho = -0.57). Thus, CT was better than radiography at showing the morphology and distribution of lung abnormalities.