Gastrointestinal leishmaniasis in human immunodeficiency virus-infected patients: report of five cases and review

We describe five cases of gastrointestinal leishmaniasis in patients with human immunodeficiency virus infection and review 10 additional cases reported in the literature. All of the patients had CD4+ cell counts of < 200/mm3, and AIDS had been previously diagnosed for 12 patients. Fever and splenomegaly were present in 46% of cases. Thirteen patients had digestive symptoms; these symptoms included diarrhea (6), dysphagia and/or odynophagia (6), abdominal pain (2), epigastric pain (2), gastrointestinal hemorrhage (1), and rectal discomfort (1). The regions of the digestive tract most frequently affected by Leishmania organisms were the duodenal mucosa (90%) and the gastric mucosa (75%). Endoscopy showed normal-appearing mucosa in 45% of cases. In 10 cases the diagnosis of visceral leishmaniasis was first made by biopsy of the gastrointestinal mucosa. In most cases treatment with antimonial agents was not effective.     

Effect of various antithrombotic regimens (aspirin, aspirin plus dipyridamole, anticoagulants) on the functional status of patients and grafts one year after coronary artery bypass grafting

From 1987 until 1991 a large prospective randomized multicentre study was performed in The Netherlands, Germany and Switzerland entitled CABADAS (Prevention of Coronary Artery Bypass graft occlusion by Aspirin, Dipyridamole, and Acenocoumarol/Phenprocoumon Study). The aim of CABADAS was to evaluate the relative efficacy of (1) aspirin, (2) aspirin plus dipyridamole, and (3) oral anticoagulants in the prevention of vein graft occlusion during the first year after aortocoronary bypass surgery. No significant difference was observed in the incidence of graft occlusion among the three treatment groups. In a subgroup of 127 CABADAS patients, studied in the Academic Medical Centre in Amsterdam, the relationship between treatment and clinical status (i.e. symptoms of angina pectoris and exercise capacity) was assessed, and the relationship between treatment and functional status of the vein grafts was determined by means of thallium-201 exercise scintigraphy. There were no differences in symptoms among the three treatment groups in the 127 patients studied. There were no significant differences either among the treatment groups, as regards exercise capacity and the number or intensity of perfusion defects, in the 81 patients who underwent thallium-201 exercise scintigraphy. The three antithrombotic treatment regimens had a similar effect on the clinical status of patients and on the functional status of venous bypass grafts one year after coronary bypass surgery. This finding underscores the CABADAS results in that aspirin may be the preferred treatment option in patients following venous bypass surgery.     

Permeability and stability in buffer and in human serum of fluorinated phospholipid-based liposomes

Calsequestrin is the major Ca(2+)-binding protein localized in the terminal cisternae of the sarcoplasmic reticulum (SR) of skeletal and cardiac muscle cells. Calsequestrin has been purified and cloned from both skeletal and cardiac muscle in mammalian, amphibian, and avian species. Two different calsequestrin gene products namely cardiac and fast have been identified. Fast and cardiac calsequestrin isoforms have a highly acidic amino acid composition. The amino acid composition of the cardiac form is very similar to the skeletal form except for the carboxyl terminal region of the protein which possess variable length of acidic residues and two phosphorylation sites. Circular dichroism and NMR studies have shown that calsequestrin increases its alpha-helical content and the intrinsic fluorescence upon binding of Ca2+. Calsequestrin binds Ca2+ with high-capacity and with moderate affinity and it functions as a Ca2+ storage protein in the lumen of the SR. Calsequestrin has been found to be associated with the Ca2+ release channel protein complex of the SR through protein-protein interactions. The human and rabbit fast calsequestrin genes have been cloned. The fast gene is skeletal muscle specific and transcribed at different rates in fast and slow skeletal muscle but not in cardiac muscle. We have recently cloned the rabbit cardiac calsequestrin gene. Heart expresses exclusively the cardiac calsequestrin gene. This gene is also expressed in slow skeletal muscle. No change in calsequestrin mRNA expression has been detected in animal models of cardiac hypertrophy and in failing human heart.     

Gastric secretory and humoral responses to anticipated feeding in five men

It is believed that humans anticipate appetizing meals by increasing vagally mediated gastric acid secretion. Studies were conducted on 5 normal male volunteers to characterize further the secretory response to anticipated meals. Plasma gastrin and glucose levels were monitored to assess the possibility that these humoral factors participated in the observed secretory changes. Subjects were not fed for 22 hr and were intubated at 10 AM. Basal gastric collections were begun, and at 1 PM on different days, subjects either (a) selected meals of choice prepared in their presence for 1 hr before nasogastric tube withdrawal and meal ingestion or (b) were not food-teased or fed. Gastric collections were obtained every 10 min during the "test" hour (1-2 PM) during both (a) and (b) studies and titrated for gastric acid. Blood samples for plasma glucose and RIA gastrin were obtained during basal and test hours every 10 min. Pentagastrin-stimulated maximal acid output studies were conducted on all subjects on separate days. Results showed a progressive and statistically significant rise in gastric acid secretion when an appetizing, self-selected meal was anticipated. The magnitude of this rise was 55% of the mean pentagastrin-induced acid response. This acid response did not correlate with changes in plasma glucose or gastrin. The study demonstrated that pure psychic stimulation may be as effective an acid stimulant as sham feeding.     

Management of recurrent penile cancer following partial or total penectomy

The initial management of localized penile carcinoma determines the probability of recurrence. Although potentially disfiguring, the management of recurrent carcinoma of the penis requires aggressive surgical resection of both the primary lesion and nodal sites to effect the best chance for long-term survival.     

A bioeconomic model for comparing beef cattle genotypes at their optimal economic slaughter end point

A bioeconomic model of a feedlot was developed for the comparison of beef cattle genotypes under specified management and marketing conditions. The optimization behavior of commercial feedlot managers is incorporated into the model using optimum economic rotation theory. The days spent in the feedlot (rotation) by a group of animals are derived using this theory so as to maximize an objective function. Differences among breeds in the present value of profits from a single rotation, expressed per animal, represent the expected price premium paid for a feeder animal of a particular breed. Feed requirements and growth rates for a genotype are predicted over time for a specified diet from estimated mature size. Estimates of carcass fatness over time as a function of the energy content of the diet and estimates of dressing percentage over time are used for each genotype. A base model is described that incorporates biological parameters estimated for 11 breeds from a major breed comparison experiment and uses prices of inputs and outputs for Ontario feedlots. Sensitivity of the model to these biological and economic assumptions is shown. When breeds are compared at constant days fed, weight, or fat depth slaughter points, rankings are inconsistent, relative to those when each breed is slaughtered at its optimal economic point. The model can be used to establish appropriate slaughter end points for comparing beef cattle breeds and crosses and to evaluate breeding objectives for feedlot traits in genetic improvement programs.     

Molecular characterization and phylogenetic distribution of the streptococcal superantigen gene (ssa) from Streptococcus pyogenes

A striking increase in the frequency and severity of invasive infections caused by Streptococcus pyogenes has occurred in recent years. Among these diseases is streptococcal toxic-shock-like syndrome (TSLS), a condition characterized by fulminant soft-tissue destruction and multiorgan failure. Streptococcal superantigen (SSA), a superantigen isolated from a TSLS-inducing, serotype M3 S. pyogenes strain, has recently been identified. We here describe the cloning, sequencing, and phylogenetic distribution of the SSA structural gene. The 783-bp open reading frame encodes a predicted 260-amino-acid protein that is similar in size to several other bacterial superantigens. The deduced sequence of the mature protein is 60.2% identical to that of staphylococcal enterotoxin B but only 49% identical to that of streptococcal pyrogenic exotoxin A. Southern blot and PCR analysis of 138 group A streptococcal strains representing 65 M protein serotypes and 15 nontypeable isolates identified ssa in 68 strains from 10 distinct clonal lineages. All ssa-positive clones expressed SSA. Of the two clones associated with TSLS, the ET 2-M3 lineage, but not the ET 1-M1 lineage, carried the SSA gene. Further analysis of the ET 2-M3 lineage found evidence for temporal variation in ssa association. Contemporary ET 2-M3 disease isolates had ssa, but two older isolates of this clone recovered in 1910 and 1920 lacked the gene. The clonal and temporal distribution patterns of ssa suggest a relatively recent acquisition of this superantigen-encoding gene by the ET 2-M3 lineage, perhaps by horizontal transfer and recombination.     

非饱和土弹塑性应力应变特性模拟

简单地回顾了非饱和土应力应变本构模型的研究概况，就非饱和膨胀性土、黄土和击实土等的变形特性作简介。在此基础上，根据硬化塑性理论和临界状态概念，提出了一个描述非饱和土应力应变特性的一般本构理论框架。该理论框架包含了几个不同的模型，能够以统一的方式描述非饱和土性的许多基本方面     

A randomized, double-blind, placebo-controlled trial of prophylactic recombinant human granulocyte-macrophage colony-stimulating factor to reduce nosocomial infections in very low birth weight neonates

Perosomus elumbis, an infrequently encountered congenital anomaly of unknown etiology, was studied in a female Holstein calf. This error of morphogenesis represents a set of multiorgan malformations that produce a deformity of the caudal one third of the fetus. In this case, the spinal and pelvic malformations were radiographed and then dissected. Intra-abdominal abnormalities of the soft tissues are also described. The normal sequential embryologic development of the vertebrate skeleton, anterior-posterior fetal positioning, and neural tube migration are discussed. An extensive literature of this birth defect in cattle (and sheep) is reveiwed. The reports from a period covering 165 years are compared with the pathologic features in this case. Chromosomal aberrations within the homeobox gene family are postulated to be contributory factors in the development of this type of dysorganogenesis.