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J Young

Publications and source records attributed to J Young.

At least 325 records · Page 18Linked to original sources
PubMed1993

Comparison of CD1 monoclonal antibodies on bovine cells and tissues.

A comparison was made of six mAbs within temporary clusters TC19 and TC28 that were previously established, or considered from unpublished data, as recognizing bovine and ovine CD1. All six immunoprecipitated a molecule of 46 kDa from iodinated thymocytes together with a second molecule of 12 kDa that appeared to be beta 2 microglobulin. mAb 20-27 (Workshop code 038) recognized a molecule expressed on bovine monocytes and B cells from bovine peripheral blood as well as thymocytes and cells with a dendritic morphology in sections. mAb CC20 (033) was shown to stain COS cells transfected with human CD1b cDNA and this mAb together with CC14 (not in workshop panel) and CC90 (007), which gave identical staining by flow cytometry and immunohistology, should all be regarded as being bovine CD1b mAb. The bovine CD1b molecule is expressed on bovine thymocytes and a proportion of cells with a dendritic morphology in tissue sections. Flow cytometric data with mAbs CC40 (039) and CC122 (043) were not sufficiently similar to data with mAb CC20 to allow the two mAbs to be regarded as CD1b although they did appear to be directed against bovine CD1 molecules. Furthermore, CC122 recognized a molecule expressed by a high proportion of cells in the lamina propria of the gut that was not recognized by the other mAbs. The findings indicate that the six mAbs recognize at least two and possibly four CD1 antigens.

Animals↗
PubMed1993

Cocaine suppresses proliferation of phytohemagglutinin-activated human peripheral blood T-cells.

Cocaine has been reported to modulate the immune system of experimental animals. Also, we observed that the drug suppresses the phytohemagglutinin (PHA)-induced proliferation of human peripheral blood mononuclear cells (PBMCs) but at concentrations extremely high relative to those seen in the blood of drug abusers. This suggested that cocaine had a relatively weak effect when tested under conditions of optimum proliferation. We, therefore, decided to examine the effect of lower concentrations of cocaine on suboptimum PHA-induced proliferation. At 0.09-12 microM, cocaine had no effect on the proliferation of PBMC in response to 0.2 micrograms/ml PHA. However, depleting the population of B-cells and monocytes resulted in a drug-induced suppression of the residual T-cells. Maximum suppression by cocaine was observed at 3 microM with both higher and lower concentrations of the drug causing less suppression. Suppression of proliferation was not influenced by either the age or sex of the peripheral blood lymphocytes (PBL) donors. The suppression of T-cell-enriched PBLs induced by cocaine could be eliminated by increasing the dose of the mitogen but was enhanced by preincubating the cells with the drug for 24 h. Also, the drug suppressed cytosolic free calcium mobilization in Fura 2/AM loaded enriched T-cell populations. These results show that cocaine moderately but consistently suppresses PHA-induced proliferation of T-cells from random blood donors at drug concentrations observed in drug abusers. The suppression is only evident under conditions of suboptimum proliferation and is accompanied by a corresponding decrease in the mobilization of cytosolic free calcium. It is suggested that the weak suppressive effect of cocaine is reversed by either helper factors produced by accessory cells or increasing concentrations of mitogen. These factors when present possibly overcome a drug-induced reduction in calcium mobilization and lymphocyte activation.

Adult↗
PubMed1993

Effect of culture conditions on IgM antibody structure, pharmacokinetics and activity.

Culture conditions affect the binding activity, charge heterogeneity, conformational stability, glycosylation, and pharmacokinetics of human monoclonal IgM HMAB-10058. The 10058 human/human/murine trioma was grown in serum-free airlift suspension culture, hollow fiber perfusion culture, or in nude mouse ascites. The ascites-produced antibody showed reduced conformational stability, greater charge and glycoform heterogeneity, and a lower average degree of sialylation than the in vitro culture-produced material. Mean residence time after IV injection in rats was approximately 80-fold greater for the ascites culture-produced material, but specific binding activity was less than 5% of that for the airlift-produced material. In vitro culture in serum-supplemented media (in a hollow fiber perfusion reactor or in shake-flasks) resulted in antibody with pharmacokinetics intermediate between the serum-free airlift and ascites-produced materials. Incubation of airlift-produced antibody in ascites fluid also resulted in material with intermediate pharmacokinetics. Conclusions regarding the effect of culture conditions on antibody product cannot be generalized, as in vitro-produced antibody derived from two related cell lines (HMAB-10233 and HMAB-10390) had long mean residence times similar to that of ascites-produced HMAB-10058.

Animals↗
PubMed1993

Associations between subunit ectodomains promote T cell antigen receptor assembly and protect against degradation in the ER.

The T cell antigen receptor (TCR) is an oligomeric protein complex made from at least six different integral membrane proteins (alpha beta gamma delta epsilon and zeta). The TCR is assembled in the ER of T cells, and correct assembly is required for transport to the cell surface. Single subunits and partial receptor complexes are retained in the ER where TCR alpha, beta, and CD3 delta chains are degraded selectively. The information required for the ER degradation of the TCR beta chain is confined to the membrane anchor of the protein (Wileman et al., 1990c; Bonifacino et al., 1990b). In this study we show that the rapid degradation of the TCR beta chain is inhibited when it assembles with single CD3 gamma, delta, or epsilon subunits in the ER, and have started to define the role played by transmembrane anchors, and receptor ectodomains, in the masking proteolytic targeting information. Acidic residues within the membrane spanning domains of CD3 subunits were essential for binding to the TCR beta chain. TCR beta chains and CD3 subunits therefore interact via transmembrane domains. However, when sites of binding were restricted to the membrane anchor of the TCR beta chain, stabilization by CD3 subunits was markedly reduced. Interactions between membrane spanning domains were not, therefore, sufficient for the protection of the beta chain from ER proteolysis. The presence of the C beta domain, containing the first 150 amino acids of the TCR ectodomain, greatly increased the stability of complexes formed in the ER. For assembly with CD3 epsilon, stability was further enhanced by the V beta amino acids. The results showed that the efficient neutralization of transmembrane proteolytic targeting information required associations between membrane spanning domains and the presence of receptor ectodomains. Interactions between receptor ectodomains may slow the dissociation of CD3 subunits from the beta chain and prolong the masking of transmembrane targeting information. In addition, the close proximity of TCR and CD3 ectodomains within the ER may provide steric protection from the action of proteases within the ER lumen.

Amino Acid Sequence↗
PubMed1993

The impact of a pure anti-androgen (flutamide) on LH, FSH, androgens and clinical status in idiopathic hirsutism.

OBJECTIVES: We assessed in women the effects of androgen suppression on gonadotrophin secretion and the therapeutic efficacy of the pure anti-androgen flutamide (2-methyl-N-[4-nitro-3-(trifluoromethyl)phenyl]-propanamide). DESIGN AND SUBJECTS: Ten women, aged 28-35 years, using an intrauterine device for contraception, were selected for this study. All women had idiopathic hirsutism with or without acne and seborrhoea. Flutamide was administered orally in a dose of 250 mg twice daily for 1 year. Basal body temperature was recorded and pelvic ultrasonography performed before and every 3 months during treatment. LH pulse frequency and amplitude (Cluster analysis) and basal and GnRH-stimulated plasma LH and FSH levels were determined on day 5 of the cycle prior to flutamide treatment, and after 6 and 12 months of therapy. Plasma total testosterone (T), non-SHBG bound T, androstenedione (A), dehydroepiandrosterone sulphate (DHEAS), androstanediol glucuronide (3 alpha-diol G) and sex hormone binding globulin (SHBG) levels were measured before and every 3 months during therapy, on day 5 of the cycle. Plasma oestradiol and progesterone levels were determined on day 22 of the studied cycles. RESULTS: Disappearance of acne and seborrhoea occurred after 2 months with a marked improvement of hirsutism at 6 months. At 12 months, hirsutism had disappeared with a Ferriman and Gallwey score < 7. No adverse side-effects, apart from transient diarrhoea in two patients, were reported with this flutamide dose. None of the patients had any disturbance of menstrual cycles which remained ovulatory. The pure anti-androgen flutamide induced no significant change in LH pulsatile profile, nor in LH and FSH responsiveness to GnRH. Plasma concentrations of steroids were not altered. Plasma SHBG and 3 alpha-diol G levels did not change during flutamide treatment. CONCLUSION: Flutamide, which interacts only with the androgen receptor, is effective for hirsutism, acne and seborrhoea, and does not disturb menstrual cyclicity or ovulation. It may represent a treatment of choice for essential hirsutism in women using safe contraceptive methods.

Acne Vulgaris↗
PubMed1993

Toxicity of pneumolysin to pulmonary alveolar epithelial cells.

Mortality during the first several days of pneumococcal pneumonia has not decreased appreciably over the past 30 years, despite the widespread use of antibiotics. Disruption of the alveolar epithelial barrier is likely an initial step in the pathogenesis of pneumococcal pneumonia. We report that soluble factors from Streptococcus pneumoniae can directly injure isolated rat alveolar epithelial cells. Using biochemical and immunological techniques, we identified pneumolysin as a major soluble S. pneumoniae toxin for alveolar epithelial cells. Alveolar epithelial cells at 24 or 72 h after isolation were equally sensitive to injury by purified pneumolysin. Purified pneumolysin substantially increased alveolar permeability in an isolated perfused rat lung model. Electron microscopy revealed that instilled pneumolysin caused widespread lung injury, primarily to type I alveolar epithelial cells. Pneumolysin toxicity to alveolar epithelial cells may be important in the pathogenesis of acute lung injury during pneumococcal pneumonia and may facilitate pneumococcal bacteremia.

Animals↗
PubMed1993

Neurosteroids: 3 alpha-hydroxy-5 alpha-pregnan-20-one and its precursors in the brain, plasma, and steroidogenic glands of male and female rats.

A RIA procedure for measuring progesterone (PROG), 5 alpha-pregnane-3,20-dione (5 alpha-DH PROG), and 3 alpha-hydroxy-5 alpha-pregnan-20-one (3 alpha,5 alpha-TH PROG) has been developed and validated by GLC/mass spectrometry. Measurements were made in intact and adrenalectomized (ADX) male rats, in cyclic, pregnant, spayed, and spayed-ADX females, and in both males and spayed females injected with PROG. The predominant contribution of the ovary to the concentrations of 3 alpha,5 alpha-TH PROG in plasma and brain, was indicated by its larger levels in females, in particular during pregnancy, and by its presence in ovarian tissue and disappearance after ovariectomy. An additional adrenal origin in both males and females was shown. Neither PROG nor 5 alpha-DH PROG disappeared from brain, contrary to plasma, after combined adrenalectomy and gonadectomy, thus suggesting that PROG might be synthetized de novo in brain. However, the concentrations of 3 alpha,5 alpha-TH PROG in plasma and brain of female rats were positively correlated with the concentrations of PROG in plasma, indicating that plasma PROG was the major precursor of 3 alpha,5 alpha-TH PROG. The direct formation of 3 alpha,5 alpha-TH PROG from PROG in brain was strongly suggested by the increased 3 alpha,5 alpha-TH PROG/PROG ratios in brain vs. plasma, when measured in control females, and after injection of PROG to both males and OVX females. It was previously reported that 3 alpha,5 alpha-TH PROG is a sedative/anxiolytic steroid, as a result of its binding to gamma-aminobutyric acid (GABA)A receptors and allosteric potentiation of GABAcergic neurotransmission. Its concentrations in brain reach indeed the neuroactive range in cyclic and pregnant females, and are compatible with a physiological role of this neurosteroid.

5-alpha-Dihydroprogesterone↗
PubMed1993

Xp22.3 deletions in isolated familial Kallmann's syndrome.

Several familial cases of Kallmann's syndrome (KS) have been reported, among which the X-chromosome-linked mode of inheritance is the most frequent. The gene responsible for the X-linked KS has been localized to the terminal part of the X-chromosome short arm (Xp22.3 region), immediately proximal to the steroid sulfatase gene responsible for X-linked ichthyosis. Large deletions of this region have been previously shown in patients affected with both X-linked ichthyosis and KS. We report here the search for Xp22.3 deletions in 20 unrelated males affected with isolated X-linked KS. Only 2 deletions were found using Southern blot analysis, indicating that large deletions are uncommon in patients affected with KS alone. Both deletions were shown to include the entire KAL gene responsible for X-linked KS. The patients carrying these deletions exhibit additional clinical anomalies, which are discussed: unilateral renal aplasia, unilateral absence of vas deferens, mirror movements, and sensory neural hearing loss.

Adolescent↗
PubMed1993

Failure of combined follicle-stimulating hormone-testosterone administration to initiate and/or maintain spermatogenesis in men with hypogonadotropic hypogonadism.

In men with hypogonadotropic hypogonadism, prolonged treatment with LH and FSH induces spermatogenesis. To compare the respective role of exogenous testosterone and intratesticular testosterone on the induction and maintenance of spermatogenesis, 10 men with hypogonadotropic hypogonadism and without history of cryptorchidism were studied. They were treated with human gonadotropins (hMG; 150 IU FSH and LH and 1500 IU hCG, im, three times weekly) or pure FSH (150 IU, im, three times a week) and testosterone (T: 250 mg, im, once a week). Five men were treated first with hMG-hCG and then with pure FSH plus T. The other five men started with pure FSH plus T. Each treatment period lasted 24 months. In all men, hMG-hCG induced spermatogenesis after 24 months, with normal motility and quality. The combination of pure FSH and T was not able to induce spermatogenesis after 24 months. In addition, sperm count dropped dramatically to 0.3 +/- 0.1 x 10(6)/mL within 3 months and to 0 after 6 months when pure FSH and T followed [corrected] hMG-hCG. Plasma T levels were increased by both treatments, but significantly more after pure FSH and T (35.3 +/- 5.2 nmol/L) than after hMG-hCG (20.4 +/- 5.2 nmol/L; P < 0.05). Plasma estradiol levels after treatment with pure FSH and T were also increased, but the difference from those obtained during hMG-hCG treatment was not significant. In conclusion, in men with complete gonadotropin deficiency, FSH and exogenous T are not able to induce spermatogenesis. Furthermore, spermatogenesis induced by LH plus FSH (hMG-hCG) cannot be maintained when exogenous T replaced LH in the regimen. Thus, exogenous T is unable to replace LH (and intratesticular T) to induce spermatogenesis. These data are noteworthy in the prospect of male contraception after a complete blockade of gonadotropin activity.

Adult↗
PubMed1993

Day hospital and home physiotherapy for stroke patients: a comparative cost-effectiveness study.

The financial cost of stroke rehabilitation is considerable but few cost-effectiveness studies are available to guide clinical practice. The Bradford community stroke trial was a randomised trial comparing day hospital attendance with home physiotherapy for elderly stroke patients leaving hospital. The outcome measurements used indicated a consistent modest advantage in favour of home physiotherapy. This advantage is now re-examined in conjunction with the quantified costs of the rehabilitation services and community support received by the two patient groups. The results show that the median cost for the day hospital patients over the first eight weeks was 620.00 pounds (interquartile range 555.00-730.00 pounds) and 385.00 pounds for the home physiotherapy group (interquartile range 240.00-510.00 pounds). These costs were significantly different (median difference 265.00 pounds, 95% confidence interval 190.00-340.00 pounds; p < 0.01). There were no significant differences between the two groups for the indirect costs. This cost-effectiveness study supports the clinical trial result that home physiotherapy should be the treatment of choice for stroke aftercare.

Aged↗
PubMed1993

Isolation and pharmacological characterization of omega-grammotoxin SIA, a novel peptide inhibitor of neuronal voltage-sensitive calcium channel responses.

omega-Grammotoxin SIA, a peptidergic blocker of voltage-sensitive calcium channel (VSCC) responses, was purified from Grammostola spatulata (tarantula spider) venom by reverse phase high performance liquid chromatography. Protease-sensitive biological activity was monitored by determining the inhibition of K(+)-stimulated influx of 45Ca2+ into rat brain synaptosomes. Electrospray mass spectrometry indicated an average molecular mass of 4109.2 Da for the native peptide. Chemical reduction of omega-grammotoxin SIA indicated the presence of three disulfide bridges. Primary sequence data confirmed the existence of six cysteine residues and 36 residues in total, with an average theoretical molecular mass of 4109.7 Da for the amidated carboxyl-terminal species. The biological profile of omega-grammotoxin SIA indicated virtually complete blockade of presynaptic vertebrate N-type as well as P-type VSCC responses. Specifically, omega-grammotoxin SIA caused a concentration-dependent and virtually complete inhibition of K(+)-evoked influx of 45Ca2+ into either rat or chick brain synaptosomes. Similar inhibition profiles were generated for the inhibition of release of either D-[3H]aspartate or [3H]norepinephrine from rat hippocampal or [3H]norepinephrine from chick cortical brain slice preparations evoked by K+ depolarization. As reported earlier, omega-grammotoxin SIA did not inhibit 125I-omega-conotoxin GVIA, [3H]PN 200-110, or [3H]desmethoxyverapamil binding to neuronal membrane fragments. To our knowledge, omega-grammotoxin SIA is the first ligand identified to block putative N-channel function without displacement of 125I-omega-conotoxin GVIA. omega-Grammotoxin SIA thus represents a novel vertebrate VSCC antagonist that inhibits neuronal N- and P-type VSCC responses.

Amino Acid Sequence↗
PubMed1993

Frequent loss of heterozygosity on chromosome 14 occurs in advanced colorectal carcinomas.

The current model for colorectal tumorigenesis defines four specific mutations (activation of a ras proto-oncogene and inactivation of the APC, p53 and DCC tumor-suppressor genes) that accumulate in a colonic epithelial cell as it progresses towards a carcinoma. However, further mutations must be needed for progression to malignancy because advanced adenomas have been observed with all four of these mutations. Loss of heterozygosity (LOH) for 11 loci spanning the distal portion of the long arm of chromosome 14 was studied in 89 sporadic colorectal adenocarcinomas and 25 adenomas. The overall rate of LOH in carcinomas was 53% (46/86 informative carcinomas). The smallest region of overlap (SRO) of deletions includes the markers D14S19 to D14S20. No LOH was seen in the 18 informative adenomas examined. There was a significant trend towards higher levels of LOH within the SRO in advanced Dukes' stages (P = 0.016). Since frequent loss of heterozygosity in a specific region of a chromosome may reflect the inactivation of a tumor-suppressor gene located there, these data suggest that a gene involved in the progression of colonic neoplasia may reside on the distal portion of the long arm of chromosome 14, and that its inactivation may be a critical event in this process.

Adenocarcinoma↗
PubMed1992

Neurosteroids: pregnenolone in human sciatic nerves.

The characterization and quantification of pregnenolone in human sciatic nerves were undertaken, following previous demonstration of the synthesis of this steroid in rat brain oligodendrocytes, to explore the hypothesis that Schwann cells may demonstrate the same biosynthetic activity. Pregnenolone was definitively identified by mass spectrometry and quantified by specific radioimmunoassay. Its concentration (mean +/- SD, 63.9 +/- 45.9 ng/g of wet tissue, n = 12) was greater than or equal to 100 times the plasma level and concentration found in tendons and muscle. No correlation was found with sex or age. Free dehydroepiandrosterone as well as sulfate and fatty acid esters of pregnenolone and dehydroepiandrosterone were also measured. Results are discussed in terms of the concept that these "neurosteroids" may be synthesized in the peripheral nervous system.

Adult↗
PubMed1992

In vivo efficacy of B43 (anti-CD19)-pokeweed antiviral protein immunotoxin against BCL-1 murine B-cell leukemia.

We show that a highly aggressive subclone of murine BCL-1 B-lineage leukemia expresses a single 2.4-kb transcript hybridizing to the human CD19 cDNA probe and reacts strongly with the anti-human CD19 monoclonal antibodies (MoAb) B43, B4, Leu-12, and J3-119. In contrast to their strong reactivity with anti-human CD19 MoAb, BCL-1 cells show no reactivity with MoAb directed against human CD22, CD72, HLA-DR, IgD, or IgM. Western blot analysis of BCL-1 whole cell lysates with the anti-human CD19 MoAb J3-119 showed a single 69-Kd protein band, which was not detected by the negative control MoAb G19.4 (anti-CD3). In contrast to BCL-1 cells, normal BALB/c splenocytes or mouse splenocyte/myeloma hybridoma cell lines did not (1) express any transcripts that hybridized to the human CD19 cDNA probe, (2) react with B43/anti-CD19 MoAb, or (3) express the 69-Kd protein that reacts with the anti-human CD19 MoAb J3-119. Murine BCL-1 B-cell leukemia thus provides a unique model of disseminated B-lineage leukemia to evaluate the antileukemic efficacy of anti-CD19 immunotoxins. This model was subsequently used to evaluate the in vivo homing ability, pharmacokinetics, and antileukemic efficacy of B43 MoAb conjugated to the plant hemitoxin pokeweed antiviral protein (PAP). B43-PAP immunotoxin (1) showed strong and antigen-specific reactivity with BCL-1 cells, (2) promptly penetrated the spleens of leukemic mice, (3) rapidly reduced the BCL-1 leukemia burden of leukemic mice and, most importantly, (4) improved survival. Finally, B43-PAP immunotoxin was more effective against BCL-1 leukemia than 700 cGy (LD100/30) total body irradiation (TBI) followed by syngeneic bone marrow transplantation (BMT).

Animals↗
PubMed1992

On the mechanism of inhibition of viral and vesicle membrane fusion by carbobenzoxy-D-phenylalanyl-L-phenylalanylglycine.

The mechanism by which the hydrophobic peptide Z-D-Phe-L-PheGly inhibits membrane fusion was investigated. Differential scanning calorimetry, 2H nuclear magnetic resonance (NMR), and 13C NMR of phosphatidylcholine bilayers in the presence of Z-D-Phe-L-PheGly indicate that this hydrophobic peptide penetrates the phospholipid bilayer but does not strongly perturb the properties of phosphatidylcholine bilayers with a large effective radius of curvature. However, Z-D-Phe-L-PheGly does affect the properties of highly curved phosphatidylcholine bilayers. Small, sonicated vesicles (SUV) of dipalmitoylphosphatidylcholine (DPPC) were made in the presence and absence of Z-D-Phe-L-PheGly. At pH 4.5, the presence of Z-D-Phe-L-PheGly inhibited the formation of SUV. At pH 6.7 and 7.4, SUV could form. Once sonication ceased and the vesicles were incubated at 23 degrees C, modest growth in vesicle size occurred for pure DPPC SUV. Rapid change to large sheetlike structures occurred in the presence of Z-D-Phe-L-PheGly. Z-D-Phe-L-PheGly appeared to favor the formation of phospholipid structures with large radii of curvature. In these experiments, Z-D-Phe-L-PheGly had access to both sides of the bilayer. If Z-D-Phe-L-PheGly was added to preformed DPPC SUV (and thus present initially only in the outer leaflet of the vesicle bilayer) and incubated at 23 degrees C, only modest growth in vesicle size was observed with little difference from control values at short to intermediate incubation times.(ABSTRACT TRUNCATED AT 250 WORDS)

1,2-Dipalmitoylphosphatidylcholine↗