Oxygen transport to muscle during exercise in chronic congestive heart failure secondary to idiopathic dilated cardiomyopathy

In chronic heart failure, oxygen delivery during exercise is impaired mainly because of failure of cardiac output to increase normally. Compensatory mechanisms are hemoglobin concentration increase, right-ward shift in the oxyhemoglobin dissociation curve, and blood flow redistribution from the nonexercising organs to the exercising muscles.     

Microsatellite DNA variation and the evolution, domestication and phylogeography of taurine and zebu cattle (Bos taurus and Bos indicus)

Genetic variation at 20 microsatellite loci was surveyed to determine the evolutionary relationships and molecular biogeography of 20 different cattle populations from Africa, Europe and Asia. Phylogenetic reconstruction and multivariate analysis highlighted a marked distinction between humpless (taurine) and humped (zebu) cattle, providing strong support for a separate origin for domesticated zebu cattle. A molecular clock calculation using bison (Bison sp.) as an outgroup gave an estimated divergence time between the two subspecies of 610,000-850,000 years. Substantial differences in the distribution of alleles at 10 of these loci were observed between zebu and taurine cattle. These markers subsequently proved very useful for investigations of gene flow and admixture in African populations. When these data were considered in conjunction with previous mitochondrial and Y chromosomal studies, a distinctive male-mediated pattern of zebu genetic introgression was revealed. The introgression of zebu-specific alleles in African cattle afforded a high resolution perspective on the hybrid nature of African cattle populations and also suggested that certain West African populations of valuable disease-tolerant taurine cattle are under threat of genetic absorption by migrating zebu herds.     

The role of laparoscopy in the management of suspected pancreatic and periampullary malignancies

Laparoscopic evaluation of patients with suspected periampullary malignancies has been utilized more frequently in recent years. Its exact role with regard to staging and surgical bypass for palliation have yet to be clearly defined. To better define the role of laparoscopy in the evaluation and palliation of periampullary malignancy, a retrospective review of the Duke experience was carried out. Fifty-three patients with suspected pancreatic or periampullary malignancies were referred for surgical evaluation at Duke University Medical Center between 1993 and 1995. All patients underwent CT scanning and lesions were classified as resectable or unresectable based on previously established criteria. Patients either underwent laparoscopic evaluation (n = 30; 11 with laparoscopic palliation) or proceeded directly to celiotomy (n = 23). Charts were reviewed for postoperative course including complications, length of stay, and hospital costs. Although laparoscopy had a sensitivity of 93.3% for metastatic disease, CT scans accurately staged 86.8% of patients missing only one patient with peritoneal/hepatic disease. Based on these results, laparoscopy may not be beneficial for every patient with a suspected pancreatic malignancy. Retrospectively an attempt was made to determine which patients benefited from laparoscopy and which patients are best served by proceeding directly to open exploration. From these data we devised an algorithm that outlines an efficient and cost-effective approach for this patient population.     

The use of synthetic lysine in the diet of lactating sows

We conducted an experiment to determine the proportion of the lysine requirement of lactating sows that can be met using L-lysine x HCl. A total of 247 Pig Improvement Company (PIC) sows (parity one to four) were randomly allotted to one of five experimental diets containing .79% apparently digestible lysine. The first four diets contained 0, .075, .150, and .225% L-lysine x HCl replacing the intact lysine, primarily derived from soybean meal. Dietary crude protein was reduced from 17.9 to 16.9, 15.8, and 14.8% respectively. The fifth diet contained .174% L-lysine x HCl (15.5% CP) with added synthetic methionine, threonine, and tryptophan to restore the ratios of these amino acids to lysine to those in the control diet with no synthetic amino acids. The average lactation length was 15.7 +/- .3 d. Diet did not affect ADFI, sow backfat loss, sow loin eye area loss, or weaning-to-mating interval. Sows consumed an average of 4.6 kg/d and were provided 36 g/d of digestible lysine. Replacing soybean meal with increasing levels of L-lysine x HCl did not affect sow weight change. The number of pigs weaned decreased and preweaning mortality increased linearly (P = .08) with increasing levels of L-lysine x HCl. Litters from sows fed the .174% L-lysine x HCl with added methionine, threonine, and tryptophan grew slower and had a higher mortality rate than litters from sows fed no synthetic amino acids (P < .05). The addition of synthetic methionine, threonine, and tryptophan to the .174% L-lysine x HCl diet did not improve litter growth rate, but it did increase preweaning mortality (P = .05) and decrease the number of pigs weaned (P = .06) compared to the .15% L-lysine x HCl with no additional synthetic amino acids. These additions also resulted in an increased sow weight loss (P = .10). These results suggest that when more than .075% L-lysine x HCl is used to meet the lysine requirement preweaning mortality is increased and the number of pigs weaned is decreased. Supplementation with methionine, threonine, and tryptophan failed to ameliorate the negative response associated with L-lysine x HCl, which suggests that other amino acids may be limiting.     

Cardiac tamponade due to Nocardia asteroides

Pericarditis with hemodynamic compromise is a rare manifestation of infection with Nocardia asteroides. To our knowledge, only six cases have been reported previously. In contrast to other cases of pericardial disease due to Nocardia, culture of the pericardial fluid in our case was negative while culture of pericardial tissue led to the diagnosis. Surgical intervention and appropriate antibiotic therapy are essential in the treatment of Nocardia pericarditis.     

Inhibition of migration of neural crest-derived cells by the abnormal mesenchyme of the presumptive aganglionic bowel of ls/ls mice: analysis with aggregation and interspecies chimeras

The terminal bowel is congenitally aganglionic in ls/ls mice. The condition has been associated with an overabundance of laminin and other matrix molecules. Aggregation ls/ls<==>C3H chimeric mice and interspecies mouse<==>quail chimeras were constructed to test the hypothesis that the aganglionosis arises because the ls/ls gut and not the neural crest is abnormal. Demonstration of beta-glucuronidase activity permitted genotypically ls/ls and C3H cells to be distinguished in the ls/ls<==>C3H chimeras. Aganglionosis did not occur in the ls/ls<==>C3H mice and ls/ls neurons were observed in the terminal bowel. Following bactransplantation of control segments of mouse gut into quail host embryos, mouse cells migrated to host targets normally colonized by cells from the neural crest; moreover, quail crest-derived cells entered the mouse gut. In contrast, cells did not migrate to these targets from presumptive aganglionic ls/ls bowel and quail crest-derived cells neither entered the ls/ls gut nor migrated through it. Laminin immunoreactivity was present in the backgrafts of murine colon and was far more abundant and widespread in those from ls/ls than in those from control animals. These data suggest that the presumptive aganglionic ls/ls bowel does not contain crest-derived cells because these cells, which are normal in ls/ls mice, do not enter it. This failure of colonization may be related to the premature formation of neurons outside the abnormal gut, a response that may be promoted by the excessive secretion of laminin by the ls/ls enteric mesenchyme.     

A masked, randomized, dose-response study between cyclosporine A and G in the treatment of sight-threatening uveitis of noninfectious origin

Thirty-two patients with sight-threatening uveitis and a decrease in visual acuity requiring systemic therapy were randomly assigned to either cyclosporine A or G in a dose-escalation study. Groups received from 2.5 mg/kg of body weight/day to 10 mg/kg of body weight/day of either drug along with low-dose prednisone. More patients taking cyclosporine G had improved visual acuity and a decrease in macular edema, which occurred more rapidly than in the other group, even at the lower doses tested. No difference in renal function was noted between groups at any doses tested. Four patients receiving cyclosporine G had hepatic alterations, but only one required cessation of the drug. The study indicates the potential usefulness of cyclosporine G, particularly at lower doses (4 mg/kg of body weight/day), which could lower the potential for serious renal complications.