Validation of computerized three-dimensional reconstruction of intravascular ultrasound: measurements of absolute luminal diameter and cross-sectional area in ex vivo human coronary arteries

Computer based 3-dimensional reconstruction transforms 2-dimensional intravascular ultrasound images into a longitudinal format facilitating analysis of luminal narrowing. To validate the accuracy of current software in measuring coronary artery diameter and cross-sectional area, in arteries with atherosclerosis, we performed 3-dimensional reconstruction in 10 human pathologic coronary arterial segments of 10-25mm length. Images were obtained using a 4.8 French catheter with pullback speed of 1mm/sec acquired at 3 frames/sec onto VHS tape. The data were digitized and intraluminal 3-dimensional reconstruction performed using a voxel-based program. Pathologic sections were obtained every 3mm, and dimensions were measured with a resolution of 0.01 mm. Maximum, minimum, and 3 other representative diameters were recorded by an observer blinded to the ultrasound diameters. Average histo-pathologic diameters were reported, and specimen cross-sectional area was then calculated. Results: In 53 sections, pathological diameters ranged from 1.4-4.5mm (mean 2.7 +/- 0.68mm) while 3-dimensional reconstructed diameters were 1.9 to 3.8mm (mean 2.6 +/- 0.54mm). Pathologic and ultrasound derived 3-dimensional reconstruction diameters had an excellent correlation (r=0.86, SEE=+/-0.36). Pathology and 3-dimensional reconstruction cross-sectional area also correlated closely (r=0.88, SEE=+/-1.50). Diameters less than 2.0mm were systematically overestimated and diameters greater than 3.5mm underestimated by 3-dimensional reconstruction. Most 3 dimensional reconstruction values were within +/- 10% of pathology, but diverged at each diameter extreme, approaching +/- 20%. Thus, computerized 3-dimensional reconstruction of ultrasound images shows excellent quantification of luminal size in the 2.0-3.5mm range, suggesting important investigative and clinical applications.     

Polymorphisms of the equine major histocompatibility complex class II DRA locus

The full extent of the polymorphism of ELA-DRA in Equidae is not yet known. Given the apparent differences in DRA polymorphisms between Equidae and other species, the aims of this study were to more fully characterize ELA-DRA, determine the extent of gene polymorphism and establish the allele-frequency distribution. An allele reference panel for the second exon of ELA-DRA was established by sequence-based typing of 69 equine DNA samples consisting of various breeds of domestic horse (Equus caballus), together with donkeys (Equus asinus), Grant's zebras (Equus boehmi) and one onager (Equus hemionus). Five of the six previously reported alleles detected using single-strand conformation polymorphism were found: ELA-DRA*0101, ELA-DRA*0201, ELA-DRA*0301, ELA-DRA*0501 (Albright-Fraser DG et al. Polymorphism of DRA among equids. Immunogenetics 1996: 43: 315-7) and ELA-DRA*0601 (GenBank accession number AF5419361). In addition to the previously reported alleles, five novel ELA-DRA alleles were detected within the ELA-DRA allele reference panel. One of these was identified in E. caballus (ELA-DRA*JBH11), one in E. boehmi and E. hemionus (ELA-DRA*JBZ185) and three in E. asinus (ELA-DRA*JBD3, ELA-DRA*JBD17 and ELA-DRA*JBH45). A total of 565 equine DNA samples were screened using reference-strand-mediated conformation analysis, a double-stranded conformation-based mutation detection system that can be used to type existing ELA-DRA alleles and identify new variants. Based on our findings, at least 11 ELA-DRA alleles are now known to exist, and this level of polymorphism at the DRA locus appears to be unique to the genus Equus. Both the previously reported alleles and the new alleles displayed a species-specific distribution.     

An assessment of the delayed hypersensitivity reaction to methylated bovine serum albumin in the mouse and its use in the evaluation of drug effects on cell mediated immune reactions

A delayed hypersensitivity (DH) reaction is induced by a sensitizing intradermal injection of methylated bovine serum albumin (MBSA) into the abdomen of mice and a subsequent challenge injection of MBSA into the hind paw. Paw volume increase is measured by mercury plethysmography. The conditions for sensitization have been investigated. Sensitization with a 0.25% MBSA emulsion resulted in a small but significant swelling of the paw following the challenge injection. The magnitude of the footpad response to the challenge injection was increased if the antigen administered in the sensitizing injection was emulsified with Freund's incomplete adjuvant. Incorporation ofMycobacterium butyricum in the emulsion greatly increased the footpad response if added at doses of 0.05 and 1 mg per animal. A higher dose (4 mg), however, resulted in a lower response. The time course of development of the delayed hypersensitivity reaction has been studied. An 8-day interval between sensitization and challenge resulted in a greater delayed hypersensitivity response than a shorter (3-day) or longer (15-, 21-, 28-day) interval. Cyclophosphamide (250 mg kg^–1) administered 3 days prior to the sensitizing injection of MBSA produced a modest enhancement of the DH reaction.On the basis of these studies a protocol for conducting the DH reaction to MBSA was established and the activity of drugs on processes underlying the sensitization phase of the reaction or processes underlying the elicitation phase of the reaction have been examined. Steroid and immunosuppressant drugs were found to inhibit the DH footpad response when dosed during the sensitization whereas several specific-anti-rheumatic and immunoactive compounds were without effect. Indomethacin and sudoxicam inhibited the DH reaction if dosed during the elicitation of the reaction but other non-steroidal anti-inflammatories tested did not significantly reduce the response. The clinically used anti-rheumatic drugsd-penicillamine and levamisole did not inhibit the elicitation phase of the DH response but niridazole at 100 mg kg^–1 did reduce the inflammatory response.This paper has been presented in part as a poster presentation to the British Pharmacological Society, 4–6 January 1978.     

No association between the Pro197Leu polymorphism in the glutathione peroxidase (GPX1) gene and schizophrenia

OBJECTIVE: Oxidative stress such as free radical-mediated neuronal dysfunction may be involved in the pathophysiology of schizophrenia. The human glutathione peroxidase (GPX1) is a selenium-dependent enzyme, which plays an important role in the detoxification of free radicals. We therefore hypothesized that the GPX1 gene, which is located on chromosome 3p21.3, may be involved in the pathophysiology of schizophrenia. The aim of this study is to examine whether a potentially functional polymorphism, a proline (Pro) to leucine (Leu) substitution at codon 197 (Pro197Leu) of the human GPX1 gene, is associated with susceptibility to schizophrenia. METHODS: We genotyped the Pro197Leu polymorphism in a total of 113 nuclear families that had a proband with schizophrenia. Genetic association was tested using the transmission disequilibrium test (TDT), the sib transmission disequilibrium test (STDT), and the family-based association test (FBAT). RESULTS: The minor allele (Leu) frequency was calculated to be 0.282. We could not find significant transmission disequilibrium of the alleles for the Pro197Leu polymorphism in the GPX1 gene in association with the presence of schizophrenia in our family sample (TDT, chi2=0.03, degrees of freedom=1, P=0.86; combined TDT-STDT, Z'=-0.052, P=0.47; FBAT, Z=0.000, P=1.000). CONCLUSION: The results of this study suggest that the GPX1 polymorphism is unlikely to be associated with susceptibility to schizophrenia.     

Relation between gastric histology and gastric juice pH and nitrite and N-nitroso compound concentrations in the stomach after surgery for duodenal ulcer

Formation of N-nitroso compounds in gastric juice has been implicated in the pathogenesis of cancer in the stomach after operation. Gastric juice was aspirated from 85 subjects: 23 were controls, 51 had previously undergone vagotomy and gastrojejunostomy, and 11 had previously undergone vagotomy and pyloroplasty. The gastric juice samples were analysed for pH, nitrite, and total N-nitroso compounds. A significant correlation was found between pH and nitrite concentration (p less than 0.01). No significant correlation was found between pH and total N-nitroso compound concentration or between nitrite and N-nitroso compound concentration. The vagotomy and gastrojejunostomy patients had higher pH values and higher concentrations of nitrites and N-nitroso compounds than controls (p = 0.01 in all cases). The 51 vagotomy and gastrojejunostomy patients also underwent endoscopy and biopsy. They were divided into three groups: group 1 (21 patients) had no intestinal metaplasia and no more than mild dysplasia; group 2 (20 patients) had intestinal metaplasia; and group 3 (10 patients) had moderate or severe dysplasia. Groups 2 and 3 both had higher pH values and higher nitrite concentrations than group 1 (p = 0.01 in all cases). There was no significant difference, however, between either group 2 or 3 and group 1 for total N-nitroso compound concentration. Since there was no simple linear relation between pH and N-nitroso compound concentration, it was concluded that formation of N-nitroso compounds at high pH was unlikely to be involved in the pathogenesis of gastric cancer in the hypochlorhydric stomach after operation. The relation between nitrite and histological abnormality was not associated with a similar relation between N-nitroso compounds and histological abnormality. It therefore appears that there is no simple relation between N-nitroso compounds and the pathogenesis of premalignant gastric mucosal changes.     

Randomized controlled trial assessing the effect of vitamin A supplementation on maternal morbidity during pregnancy and postpartum among HIV-infected women

OBJECTIVE: To determine whether low-cost treatment of HIV using vitamin A would be beneficial, we examined the effect of vitamin A supplementation on morbidity of HIV-1 infected women. METHODS: We conducted a randomized, double blind placebo-controlled trial at King Edward VIII Hospital, in Durban, South Africa. In total, 312 HIV-seropositive pregnant women between 28 and 32 weeks' gestation were recruited into this trial. Patients were randomized to receive placebo or 5,000 IU retinyl palmitate and 30 mg beta-carotene daily. At delivery of their children, patients received placebo or 200,000 IU retinyl palmitate. The main outcome measures were pre- and postnatal report of HIV-related symptoms. RESULTS: Vitamin A did not confer any significant beneficial effect on the report of either HIV or pregnancy-related symptoms during the pre- or postnatal period. CONCLUSION: In this study of HIV-infected pregnant women, vitamin A supplementation given in doses designed to decrease mother-to-infant transmission did not result in significant beneficial effect on reported symptoms pre- or postnatally. Further investigation with larger number of participants, tailoring supplementation for specific clinical conditions, outside the context of pregnancy, is required to help clarify the possible clinical benefits of vitamin A.     

Cloning and expression of the major secreted cathepsin B-like protein from juvenile Fasciola hepatica and analysis of immunogenicity following liver fluke infection

The functions of the cathepsin B-like proteases in liver flukes are unknown and analysis has been hindered by a lack of protein for study, since the protein is produced in small amounts by juvenile flukes. To circumvent this, we isolated and characterized a cDNA encoding the major secreted cathepsin B from Fasciola hepatica. The predicted preproprotein is 339 amino acids in length, with the mature protease predicted to be 254 amino acids long, and shows significant similarity to parasite and mammalian cathepsin B. Only one of the two conserved histidine residues required for cathepsin B exopeptidase activity is predicted to be present. Recombinant preproprotein was produced in yeast, and it was shown that the recombinant proprotein can undergo a degree of self-processing in vitro to the mature form, which is active against gelatin and synthetic peptide substrates. The recombinant protein is antigenic in vaccinated rats, and antibodies to the protein are detected early after infection of rats and sheep with F. hepatica. The kinetics of the response to cathepsin B and cathepsin L after infection of sheep and rats confirm the temporal expression of these proteins during the life cycle of the parasite.