Search PubMed⌕ Search

Biomedical subjects

Y Lou

Publications and source records attributed to Y Lou.

At least 73 records · Page 4Linked to original sources
PubMed1996

Breed differences in boar taint: relationship between tissue levels boar taint compounds and sensory analysis of taint.

A total of 228 intact male pigs form Duroc, Hampshire, Landrace, and Yorkshire breeds were used in the experiment. Samples of salivary gland and backfat were collected at slaughter for colorimetric assay of salivary and fat 16-androstene levels and fat skatole levels. Fat levels also were tested by a sensory panel using an R-index technique for detecting the presence of boar taint. The proportion of tainted carcasses determined by the sensory panel was 5.0% for androstenone and 11.4% for skatole, with a combined total of 15.0% tainted from either source. Sensory analysis of taint showed a lower proportion (P < .05) of tainted carcasses in Hampshire, with no difference in taint across the other three breeds. Analysis of taint compounds indicated that overall 14.5% of pigs had salivary gland 16-androstene levels and 20.9% had fat 16-androstene levels above acceptable limits. There was a higher (P < .05) proportion of Duroc pigs above the threshold levels for 16-androstenes in both salivary gland and fat. Landrace pigs had the lowest (P < .05) average tissue concentrations of steroids and skatole. Across breeds, only 1.8% of pigs had fat skatole concentrations above .25 ppm, which has been suggested as threshold levels of skatole for taint. The canonical correlation coefficient between fat compound levels and the R-indices of fat 16-androstenes and skatole was .40 (P < .001). Our results indicate breed differences in tissue levels of taint compounds and in taint assessed by a sensory panel. Levels of 16-androstene steroids were highly associated with taint, but more pigs had measured levels above the threshold than those identified as tainted by sensory analysis. Levels of fat skatole were low overall and did not account for all the pigs judged as tainted from skatole by sensory analysis.

Androstenes↗
PubMed1995

A zona pellucida 3 peptide vaccine induces antibodies and reversible infertility without ovarian pathology.

Zona pellucida 3 (ZP3) is a major glycoprotein of the zona pellucida that possesses the sperm receptor function. ZP3 induces autoantibody that can block sperm/oocyte interaction. However, the feasibility of a ZP3 contraceptive vaccine has been marred by the finding that ZP3-specific T cells mediate ovarian autoimmune disease. Moreover, as reported in this work, only some inbred mouse strains respond to the ZP3 peptide. We now describe a chimeric peptide that induces Abs to native ZP3 regardless of the MHC haplotype of the inbred mice tested. Study in one mouse strain resulted in reduction in fertility that correlates well with zona pellucida Ab titer, and most importantly, the mice do not develop concomitant autoimmune oophoritis. Moreover, the infertility was completely reversible. The design of the vaccine chimeric peptide is governed by the inclusion of two essential components: 1) a promiscuous foreign T cell peptide capable of eliciting a Th cell response regardless of the MHC haplotype of the animals, and 2) the native B cell peptide of ZP3 that has been modified by substitution of residue(s) critical for T cell but not B cell response to ZP3.

Amino Acid Sequence↗
PubMed1995

The use of gelatin microparticles to delay the release of readily water-soluble materials.

The adsorption of D-arabinose onto gelatin microparticles demonstrated a Langmuirian adsorption pattern. Evaluation of the dissolution behaviour of D-arabinose-loaded gelatin microparticles suggested that the saccharide, loaded at a level below the adsorption saturation level, was released uniformly over a 14-h period after the loaded gelatin microparticles had been lyophilized for a second time. When dissolution curves were corrected for the initial burst effect seen after the gelatin microparticles had been loaded at higher levels of D-arabinose and lyophilized, steady-state release rates were also evident over prolonged periods. In addition, it was evident that the D-arabinose was adsorbed onto internal surfaces of the hydrated gelatin matrix. Calculation of this internal surface demonstrated the influence of the concentration of the glutaraldehyde used as a cross-linking agent and this parameter, in turn, influenced both the adsorption maxima and the subsequent equilibrium release rates. Application of this data base to a highly water-soluble complex polysaccharide antineoplastic agent, which has a higher molecular weight (22.4 kDa vs 150 Da), demonstrated similar behaviour in that a near zero-order release pattern over at least 16 h could be obtained by attention to the conditions under which the gelatin microparticles were made and subsequently loaded before lyophilization.

Adsorption↗
PubMed1995

Interaction between fibronectin-bearing surfaces and Bacillus Calmette-Guérin (BCG) or gelatin microparticles.

Gelatin, prepared commercially by degradation of animal collagen, was studied to see whether it had an affinity for fibronectin, which has a known affinity for collagen, and whether gelatin-based drugs could be used to target fibronectin-excreting tumours. Bacillus Calmette-Guérin (BCG) vaccine, an attenuated strain of Mycobacterium bovis, is currently the most effective treatment for superficial transitional cell carcinoma of the bladder. The living cells of the BCG vaccine associate with the fibronectin-bearing surfaces of the tumour. Using a multi-well culture plate technique, gelatin microparticles were shown to be adsorbed onto murine S180 sarcoma cells and this reaction was substantially inhibited by the addition of human plasma fibronectin. The avidities of various BCG substrains and gelatin microparticles for glass-bound fibronectin were measured and the association constants determined. The gelatin microparticles associated with the fibronectin with equal avidity as the BCG cells. The results suggest that this model system may allow the investigation of gelatin-based drug delivery devices capable of targeting fibronectin-bearing surfaces associated with some tumours.

Adsorption↗
PubMed1995

Pulmonary function tests in HIV-infected patients without AIDS. Pulmonary Complications of HIV Infection Study Group.

To determine the prevalence, incidence, and types of lung diseases that occur in association with HIV infection, 1,353 subjects, including HIV-seropositive homosexual men, injection drug users, female sexual partners of HIV-positive men, and HIV-seronegative control subjects from the first two transmission categories were evaluated prospectively in a multicenter study. Patients with AIDS at the time of initial evaluation were excluded. One thousand two-hundred ninety-four subjects who had no AIDS-defining diagnosis within 3 mo of enrollment had measurements of FVC, FEV1 and DLCO at the time of enrollment. As a group, all subjects had mean values of FVC and FEV1 close to 100% predicted. Those with CD4 counts below 200/mm3 had slightly reduced DLCO compared with the others. Subjects with a history of HIV-associated symptoms (thrush, weight loss, herpes zoster) also had a reduced DLCO compared with those without symptoms. Injection drug users had reduced FVC, FEV1 and DLCO compared with homosexual men and female sexual partners of HIV-infected men, with DLCO more substantially reduced. Part of the reduction in DLCO in drug users was attributable to factors other than HIV infection, especially cigarette smoking and race. Using predicted values that take cigarette smoking into account, the prevalence of abnormality in DLCO was higher among injection drug users (33.3%) than among homosexual men (11.2%) and female sexual partners (12.7%). These results show that advanced HIV infection, characterized by CD4 count < 200/mm3 or HIV-associated symptoms, and factors unrelated to HIV infection, including race, cigarette smoking, and injection drug use, are all associated with reductions in DLCO measurements.

Bisexuality↗
PubMed1994

In-vivo and in-vitro targeting of a murine sarcoma by gelatin microparticles loaded with a glycan (PS1).

PS1, a complex polysaccharide derived from Mycobacterium bovis (Bacillus Calmette-Guérin, BCG) with considerable antitumor activity in-vivo, was loaded onto gelatin microparticles (mean diam. 1.45 micron) at a level shown to not produce the burst effect often seen with drug-loaded microparticulate systems. In-vitro dissolution experiments had demonstrated a sustained-release behaviour, with a half-life of approximately 8 h for what is an extremely water-soluble material. These PS1/gelatin systems had no measurable cytotoxicity against an S180 murine sarcoma cell in-vitro although fibronectin-mediated targeting of the microparticles for the tumour cells could be demonstrated. Injection into mice, with the S180 cells, of PS1 solutions or suspensions of PS1-loaded gelatin microparticles resulted in almost identical dose-related suppression for the tumour cell growth. When injected at intervals following injection of the tumour cells, however, for a period of 24-48 h there was a relatively enhanced activity of the formulated PS1, compared with the aqueous solution, after which both formulated and unformulated material became progressively less effective.

Animals↗
PubMed1993

T cell peptide of a self-protein elicits autoantibody to the protein antigen. Implications for specificity and pathogenetic role of antibody in autoimmunity.

A 13-mer peptide of the ZP3 glycoprotein from mouse zona pellucida has a T cell epitope that induces autoimmune oophoritis and a B cell epitope that reacts with antibody to murine ZP3. When the B cell epitope was partially truncated, the ZP3 peptides no longer induced antibody to the B cell epitope, but unexpectedly they elicited antibody to the zona pellucida. These autoantibodies were of IgG class, detected in sera and bound to the ovarian zona pellucida. That an exclusive T cell peptide of murine ZP3, without coinjection of the whole ZP3 protein, elicited autoantibodies against ZP3 outside the T cell peptide was confirmed as follows. First, the ZP3 T cell peptide did not contain additional B cell epitopes that cross-reacted with native ZP3. Second, endogenous ovarian Ag were required because autoantibodies were not detected in ovariectomized mice immunized with ZP3 peptides lacking the B epitope. This autoantibody amplification phenomenon demonstrates conclusively that 1) self-reactive B cells for ovarian autoantigens respond to endogenous ovarian Ag in vivo after activation of ZP3-specific Th cells and 2) serum antibody in an autoimmune disease need not mirror the immunogen that initiates the disease process. Nonetheless, the autoantibodies bound to the zona pellucida in vivo and are potentially important in disease pathogenesis.

Amino Acid Sequence↗
PubMed1993

Inhibition of murine sarcoma cell adherence to polystyrene substrata by bacillus Calmette-Guérin: evidence for fibronectin-mediated direct antitumor activity of BCG.

Bacillus Calmette-Guérin (BCG) inhibited adherence of S180 mouse sarcoma cells and WI38 human diploid fibroblasts to the polystyrene substratum of 24-well cluster dishes in a dose-dependent manner. This property was retained by washed or heat-killed bacilli, but not by the vaccine filtrate or by the spent bacterial culture medium. Adhesion of bacilli to nonadherent S180 cells was demonstrated by light and scanning electron microscopy, but was not seen after trypsinization of adherent cells, indicating that bacilli bind to cell-surface adhesins. Preincubation of bacilli with human fibronectin abolished their ability to inhibit S180 adherence, suggesting that the phenomenon may be mediated by interaction of bacilli with cell-surface fibronectin. Fibronectin pretreatment of the bacteria also decreased their inhibition of S180 tumor growth in vivo, indicating that this mechanism may be at least partly responsible for BCG vaccine's observed antineoplastic activity.

Adsorption↗