I2Cnet medical image annotation service

Forty Aspergillus japonicus and A. aculeatus strains, most of them wild-type isolates, were examined using various molecular and phenotypic techniques. The rDNAs proved to be invariable (even strains of the species A. aculeatus exhibited the same restriction profile), while the strains could be classified into seven different mtDNA RFLP groups. Hybridisation data suggest that six of these mtDNA types have certain common restriction sites, while mtDNA type 7, which was exhibited by some A. aculeatus strains, probably has quite different mtDNA organisation and their size was smallest among the strains studied. The RAPD technique and isoenzyme analysis revealed some variabilities within these RFLP groups and strain specific features could also be recognised. Carbon source assimilation spectra were found to be very distinctive for strains of A. japonicus, A. aculeatus and A. niger, providing a useful tool for pre-characterising new wild-type isolates of black Aspergilli. Only a limited correlation was observed between the dendrograms based on genotypic and phenotypic characters.     

Vascular endothelial growth factor upregulates constitutive cyclooxygenase 1 in primary bovine and human endothelial cells

The effect of the angiogenic cytokine vascular endothelial growth factor (VEGF) on nitric oxide synthase (NOS) and cyclooxygenase (COX) expression was examined in human (HUVEC) and bovine (BAE) endothelial cells. VEGF (10 ng/ml) induced constitutive COX-1 expression in both HUVEC and BAE, but not the cytokine-inducible isoform, COX-2, inducible NOS or endothelial NOS. In HUVEC, VEGF (10 ng/ml) increased COX activity, but COX inhibitors had no effect on the proliferative response of endothelial cells to this cytokine. In conclusion the induction of COX-1 by VEGF is not involved in the mitogenic response of endothelial cells, but may be an important regulatory mechanism in the maintenance of vascular integrity.     

Purification of the lysosomal sialic acid transporter. Functional characteristics of a monocarboxylate transporter

Sialic acid and glucuronic acid are monocarboxylated monosaccharides, which are normally present in sugar side chains of glycoproteins, glycolipids, and glycosaminoglycans. After degradation of these compounds in lysosomes, the free monosaccharides are released from the lysosome by a specific membrane transport system. This transport system is deficient in the human hereditary lysosomal sialic acid storage diseases (Salla disease and infantile sialic acid storage disease, OMIM 269920). The lysosomal sialic acid transporter from rat liver has now been purified to apparent homogeneity in a reconstitutively active form by a combination of hydroxyapatite, lectin, and ion exchange chromatography. A 57-kDa protein correlated with transport activity. The transporter recognized structurally different types of acidic monosaccharides, like sialic acid, glucuronic acid, and iduronic acid. Transport of glucuronic acid was inhibited by a number of aliphatic monocarboxylates (i.e. lactate, pyruvate, and valproate), substituted monocarboxylates, and several dicarboxylates. cis-Inhibition, trans-stimulation, and competitive inhibition experiments with radiolabeled glucuronic acid as well as radiolabeled L-lactate demonstrated that L-lactate is transported by the lysosomal sialic acid transporter. L-Lactate transport was proton gradient-dependent, saturable with a Km of 0.4 mM, and mediated by a single mechanism. These data show striking biochemical and structural similarities of the lysosomal sialic acid transporter with the known monocarboxylate transporters of the plasma membrane (MCT1, MCT2, MCT3, and Mev).     

Type C retrovirus released from porcine primary peripheral blood mononuclear cells infects human cells

As part of the evaluation of porcine cells, tissues, and organs intended for transplantation into humans, we investigated the conditions required to induce expression and release of porcine endogenous retrovirus (PoEV) from primary cells. Pigs contain endogenous retroviral sequences encoding infectious retrovirus, yet little is known about the conditions required to activate the expression and release of PoEV from primary cells. We show here that mitogenic activation of peripheral blood mononuclear cells (PBMC) isolated from the National Institutes of Health (NIH) miniature pig and the Yucatan pig resulted in the activation and release of an infectious type C retrovirus. Coculture of activated porcine PBMC with pig or human cell lines resulted in the transfer and expression of PoEV-specific sequences and the establishment of a productive infection. Sequence comparison of portions of the PoEV pol gene expressed in pig cell lines productively infected with virus derived from NIH miniature pig and Yucatan pig PBMC revealed marked similarity, suggesting that one or a few loci may be capable of being activated to yield an infectious virus. These findings demonstrate that the presence of endogenous viruses in source animals needs to be carefully considered when the infectious disease potential of xenotransplantation is being assessed.     

Use of a cysteine proteinase from Carica candamarcensis as a protective agent during DNA extraction

We describe the use of a plant cysteine proteinase isolated from latex of Carica candamarcensis as a protective agent during isolation of bacterial DNA following growth in culture of these cells. Between 100 to 720 units of proteinase (1 microgram = 6 units) afforded good DNA protection when incubated with various kinds of microorganisms. Agarose gel electrophoresis showed that the resulting DNA was similar in size to DNA preparations obtained by treatment with proteinase K. The viability of the resulting material was checked by PCR amplification using species-specific primers. After standing at room temperature (25 degrees C) for 35 days, the enzyme lost 10% of its initial activity. The enzyme stability and good yield of DNA suggest the use of this proteinase as an alternative to proteinase K.     

Heparin coating of extracorporeal circuits inhibits contact activation during cardiac operations

OBJECTIVE: The choice of a valve substitute remains a challenge in young patients, with numerous reports of early degeneration and calcification of biological valves in this age group. Therefore an assessment of the long-term results after mechanical aortic valve replacement in children was initiated. METHODS: A retrospective study was conducted in 54 consecutive patients aged 1.1 to 17 years (mean 12.8 +/- 4 years) operated on between 1975 and 1993. Aetiology was congenital in 34 patients, rheumatic in 13, infectious in 5, and dystrophic in 2. Concomitant surgery included mitral valve replacement (10), aortic annulus enlargement (9), correction of truncus arteriosus (7), Bentall operation (2), coarctation repair (2), tricuspid valvuloplasty (2), correction of double outlet right ventricle (1), and replacement of a right ventricle to pulmonary artery conduit (1). A Bjork-Shiley valve was implanted in 14 patients, and a St Jude Medical valve in 40. All patients were given Warfarin with a monthly INR control. Follow-up was completed through questionnaires mailed to referring physicians and direct clinical examination. RESULTS: Overall early mortality was 13% (7 cases), and 6% (2 cases) in the 32 patients operated on after 1984. Follow-up was complete in 45 survivors (2 lost to follow-up), with a total follow-up of 261 patient-years. There were 6 late deaths, 4 being cardiac and due to persistent LV dysfunction, and 2 valve-related, due respectively to major gastro-intestinal bleeding and massive thromboembolism. Linearized rates of valve thrombosis and anticoagulant-related hemorrhage were both 0.3% per patient-year. Actuarial survival rate was respectively 84.5% at 5 years and 70.2% at 10 years. Reoperation was necessary in 3 patients for recurrent LV outflow tract obstruction. One patient with severe LV dysfunction is awaiting a heart transplant. CONCLUSION: We conclude that the longterm outcome after mechanical aortic valve replacement in children and adolescents is satisfactory and comparable to currently available reports on biological substitutes. The mandatory anticoagulant therapy is well tolerated in this age group.     

Improved results in the management of surgical candidates with lung cancer

BACKGROUND: Perioperative mortality and morbidity after lung resection for carcinoma are generally reported to be 3% to 6% and 15% to 30%, respectively, and higher in the elderly and those with limited cardiopulmonary reserve. METHODS: To minimize this risk and extend the surgical option to more high-risk patients, we adopted a protocol in 1991 that included preoperative digitalis, subcutaneous heparin and venoocclusive stockings, aggressive perioperative pulmonary toilet, and video-directed limited resections for many patients with limited pulmonary reserve. In October 1996, we reviewed our results with 173 consecutive patients (median age, 60 years; range, 17 to 89 years) undergoing operation for suspected lung carcinoma. Forty-one patients were 70 years old or older, and 70 patients were considered high risk on the basis of advanced age (> or = 70 years), poor cardiac or pulmonary reserve, or serious medical comorbidity. Procedures included pneumonectomy (n = 31), lobectomy (n = 83), bilobectomy (n = 12), and limited resection (n = 45). Two patients had unresectable disease. RESULTS: Hospital mortality was 1.6% (3/173) and morbidity was experienced by 15% (26/173). Among the high-risk subgroup mortality was 4.2% (3/70) and morbidity was 20% (14/70; p < 0.03). For the older patients these values were 4.8% (2/41) and 17.9% (7/41), respectively. CONCLUSIONS: Morbidity and mortality from lung resections may be minimized with the perioperative management strategy outlined above. This would allow more high-risk patients to benefit from surgical resection, and do so with an acceptably low risk.     

Risk factors for cardiovascular disease in children with type I diabetes: Part 1

This study characterizes the pharmacokinetics of bumetanide after an intravenous dose of 0.05 or 0.10 mg/kg to 14 neonates (weight range 820-4,000 g; gestational age 26-40 weeks) during the first week of life. Blood samples and urine were collected for up to 12 h after dosing. Estimated serum clearance was 0.2-1.0 ml/min.kg (range), volume of distribution was 0.22 l/kg (range 0.11-0.32 l/kg), and the harmonic mean half-life was 6-7 h (range of 4-19 h). Nonrenal clearance accounted for 58-97% of the serum clearance with the presence of certain oxidative metabolites of bumetanide in the urine. These findings suggest higher dosing requirements and prolonged intervals as compared to adults. Utilizing these pharmacokinetic data, pharmacodynamic and ototoxicity studies should be conducted to establish a safe and effective neonatal dose.