Pharmacologic resolution of functional outflow tract obstruction after mitral valve repair

A 74-year-old woman with mitral regurgitation secondary to ruptured chordae tendineae, complicated by a cleft in the posterior mitral leaflet and a severely calcified mitral annulus, underwent mitral valve repair by implantation of polytetrafluoroethylene chords and closure of the cleft, without the use of an annuloplasty ring. Immediately after the repair severe left ventricular outflow tract obstruction developed secondary to the systolic anterior motion of the mitral valve. Echocardiography identified the cause as functional, in the presence of a hypertrophic left ventricle with no significant preoperative intraventricular dynamic gradient. The obstruction was severe enough to render impossible the weaning of the patient from cardiopulmonary bypass. This problem was reversed by the infusion of beta-blocking agents into the extracorporeal circuit.     

Left-Atrial-Appendage Occluder Migrates in an Asymptomatic Patient

Percutaneous closure of the left atrial appendage (LAA) is a new approach to the prevention of cardioembolic events in patients with atrial fibrillation. We implanted an LAA occlusion device (Amplatzer™ Cardiac Plug) in a 70-year-old woman via a transseptal approach. Upon her discharge from the hospital, a transthoracic echocardiogram showed stable anchoring of the device; 6 months after implantation, a routine transthoracic echocardiogram revealed migration of the occluder into the left ventricular outflow tract, in the absence of symptoms. We surgically removed the device from the mitral subvalvular apparatus and closed the LAA with sutures. This case shows that percutaneous LAA occlusion can result in serious adverse events, including device migration in the absence of signs or symptoms; therefore, careful follow-up monitoring is mandatory.     

Normal neurodevelopment in four young children treated with bone marrow transplantation for acute leukemia or aplastic anemia

Longitudinal neurodevelopmental studies of four consecutive young children treated by bone marrow transplantation for acute leukemia or aplastic anemia are presented. The children, the only four children less than 2 years of age who have received bone marrow transplants for these diseases at UCLA Medical Center, ranged in age from 36 weeks to 24 months at the time of transplantation. Conditioning involved high-dose cyclophosphamide treatment; three also had total body irradiation prior to bone marrow transplantation. Their respective outcomes after follow-up times of 28 months to 71 months posttransplantation are remarkable for normal somatic growth and normal development of intelligence, language, perception, and motor coordination. These findings indicate that future therapeutic studies of infants and young children with acute leukemia or aplastic anemia using total body irradiation, cyclophosphamide, and bone marrow transplantation are not contraindicated by risks of debilitating neurodevelopmental sequelae.     

Human and mouse genomic sequences reveal extensive breakpoint reuse in mammalian evolution

The human and mouse genomic sequences provide evidence for a larger number of rearrangements than previously thought and reveal extensive reuse of breakpoints from the same short fragile regions. Breakpoint clustering in regions implicated in cancer and infertility have been reported in previous studies; we report here on breakpoint clustering in chromosome evolution. This clustering reveals limitations of the widely accepted random breakage theory that has remained unchallenged since the mid-1980s. The genome rearrangement analysis of the human and mouse genomes implies the existence of a large number of very short "hidden" synteny blocks that were invisible in the comparative mapping data and ignored in the random breakage model. These blocks are defined by closely located breakpoints and are often hard to detect. Our results suggest a model of chromosome evolution that postulates that mammalian genomes are mosaics of fragile regions with high propensity for rearrangements and solid regions with low propensity for rearrangements.     

Differential effects of Pitressin on blood flow and oxygen extraction in canine vascular beds.

Physiologic studies in dogs have been performed with an intravascular flow/diameter sensor which can be introduced directly into the aorta or its branch vessels through a percutaneous radiologic catheter. These studies have focused upon attempts to devise a clinically practical means to protect the small intestine from radiation damage during therapy of abdominal and pelvic malignant tumors. The effects on superior mesenteric, renal, and lower extremity blood flows of controlled infusions of Pitressin given directly into the superior mesenteric artery or into a peripheral vein have been measured. In addition, using these regional flow measurements and arteriovenous differences in oxygen content, regional tissue oxygen extraction rates during Pitressin infusions have also been estimated. The data show that intravenous Pitressin at an infusion rate of 0.0124 U/kg/min may be almost as effective as Pitressin given directly into the superior mesenteric artery in lowering superior mesenteric blood flow (40%-70% reduction for intravenous, 50%-70% for direct arterial infusions) and intestinal oxygen extraction (20%-40% reduction for intravenous, 40%-50% for direct arterial infusions). The effects of Pitressin at similar dose rates on the kidney and the lower extremity are less reproducible, and it is possible that relatively selective radiation protection of the intestine using systemic (intravenous) infusions of Pitressin during abdominopelvic radiotherapy might be achievable.     

Smoking among low-income pregnant women: an ethnographic analysis.

This article presents findings from a qualitative study of 53 low-income women who were smokers at the onset of pregnancy. Study participants were interviewed during pregnancy to document smoking trajectories and factors contributing to, or undermining, harm reduction and quit attempts. Thirty percent of women quit smoking completely, 43% engaged in sustained harm reduction, and 26% reduced their smoking levels intermittently. Case studies of women are presented to illustrate reasons for quitting, harm reduction practices, and factors influencing relapse and smoking continuation. Women's motivations to quit are highlighted. Moral identity as a mother was found to be a key motivating factor behind women's quit attempts. Future programs targeting this population would do well to acknowledge moral identity as an issue and recognize the challenges of quitting for women with limited social support and little control over their immediate environment.     

Use of the McGill Pain Questionnaire to measure pain: a meta-analysis

A meta-analysis of 51 studies was done to estimate normative mean McGill Pain Questionnaire (MPQ) scores and to assess pain quality and pain intensity as measured by the MPQ in 3,624 subjects with seven painful conditions. Across the painful conditions, all of the estimated normative mean scores were no more than 50% of the maximum score, suggesting that scores may be skewed to the left. Although the estimated normative mean scores were similar among the seven painful conditions, higher affective scores appeared to differentiate chronic painful conditions from acute painful conditions. Of the 78 MPQ words that describe pain quality, only 19 were selected by more than 20% of the subjects. Data reported in the majority of these studies were inadequate to test for differences in scores or word selection pattern by the seven painful conditions.     

Hair chromium content of women with gestational diabetes compared with nondiabetic pregnant women.

Hair chromium concentration (HCC) of normal and diabetic pregnant women was determined by atomic-absorption spectroscopy. For nondiabetic pregnant women the value from 68 hair samples was 472 +/- 61 ng/g (mean +/- 95% CI); for gestational diabetics it was 734 +/- 155 ng/g from 42 hair samples. The difference was highly significant (P less than 0.005). Intermediate hair chromium concentrations were observed in 20 pregnant women with pregestational, overt diabetes mellitus (mean: 575 +/- 182 ng/g). Fifty-two women had a second hair sample taken later during pregnancy that showed a significant decrease in HCC (P less than 0.05). However, this decrease was confirmed only for the diabetic pregnant group. Age and parity did not influence the HCC. The data suggest that impaired utilization of chromium may be a possible etiology for gestational diabetes mellitus.     

Prevention of graft rejection following bone marrow transplantation

Bone marrow transplantation from an HLA-identical sibling is increasingly used in the treatment of severe aplastic anemia. One major problem with this approach is graft rejection that occurs in 25%-60% of patients conditioned for transplantation with cyclophosphamide. At most transplant centers it has been difficult to accurately identify patients at high risk for graft rejection. We studied a conditioning regimen of cyclophosphamide (200 mg per kg) and low-dose total body irradiation (3 Gy; equivalent to 300 rad) in 23 consecutive unselected patients with aplastic anemia followed for a minimum of 6 mo. There was only one episode of graft rejection. Graft-versus-host disease and interstitial pneumonitis were not increased by the more intensive conditioning regimen. Actuarial survival was 61% at 1 yr and 49% at 2.5 yr. Cyclophosphamide and low-dose total body irradiation is an effective conditioning regimen in patients with aplastic anemia. It may be particularly useful when accurate predictive tests of graft rejection are not available as is the case in most transplant centers.