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J L Smith

Publications and source records attributed to J L Smith.

At least 37 records · Page 2Linked to original sources
PubMed2002

Production and regulation of leptin in bovine mammary epithelial cells.

Previously, leptin has been found in human and rodent mammary tissue. The present research was conducted to determine (1) if leptin is produced by bovine mammary epithelial cells and (2) if leptin production in bovine mammary epithelial cells is hormonally regulated. Western blot analysis indicated the presence of leptin in bovine milk, while reverse transcription-polymerase chain reaction (RT-PCR) indicated the presence of leptin mRNA in mammary tissue and cultured bovine mammary epithelial cells (MAC-T cell line). A real time RT-PCR method was developed that allowed quantitative assessment of bovine leptin mRNA over approximately 3 orders of magnitude. Time course studies indicated a rapid increase in leptin mRNA in response to insulin or insulin-like growth factor-I (IGF-I). When normalized against bovine GAPDH as an internal control, 0.5 or 1h treatment with 10 ng/mL insulin gave 39+/-4 and 64+/-2-fold increase in leptin mRNA compared with 0 h control. Leptin mRNA was increased 257+/-9 and 75+/-23-fold by 0.5 or 1h treatment with 10 ng/mL IGF-I. Dose response studies indicated significant increases in leptin mRNA in response to as little as 1 ng/mL insulin or 0.1 ng/mL IGF-I. Maximum increase in leptin mRNA was observed in response to 10 ng/mL insulin and 10 ng/mL IGF-I. These results indicate that production of leptin by bovine mammary epithelial cells can be regulated by factors known to alter mammary function and nutrient partitioning. This suggests that leptin may be an autocrine/paracrine signal in the bovine mammary gland.

Animals↗
PubMed2002

TCR usage and cytokine expression in peripheral blood and BAL T cells.

T cells are thought to play an important regulatory role in atopic asthma. We hypothesized that human blood and BAL T cell subsets bearing various TCR-Vbeta genes might show selective differences in their cytokine profile. Peripheral blood (PB) and bronchoalveolar lavage (BAL) T cells from seven atopic asthmatic and six non-atopic non-asthmatic subjects were stimulated with PMA and ionomycin in the presence of monensin and analysed for TCR-Vbeta expression and production of cytokines at the single cell level. The percentage of IFN-gamma- and IL-2-producing BAL T cells was elevated compared with PB T cells from both the asthmatic subjects and the non-atopic, non-asthmatic controls. A small percentage of PB and BAL T cells produced IL-4 and IL-5, in asthmatic and normal subjects. In peripheral blood, the percentage of T cells expressing each cytokine was similar in the various TCR-Vbeta subsets and in total CD3+ T cells in all normal and six of seven asthmatic subjects. However, there was a substantial degree of heterogeneity in the cytokine profile of BAL TCR-Vbeta subsets compared with the total CD3+ T cells. This was more obvious in the asthmatic subjects with a reduction in the percentage of IFN-gamma- and IL-2-expressing T cells (five of seven asthmatic subjects) and an increase in the percentage of IL-4- and IL-5-expressing T cells (two of seven asthmatic subjects). These data confirm previous findings of an elevated proportion of IFN-gamma- and IL-2-producing BAL T cells while only a small proportion of PB and BAL T cells produce IL-4 and IL-5. Moreover, subsets of BAL T cells, defined by their TCR-Vbeta usage, may differ in their cytokine profile compared with the total CD3+ T cells, implying that T cells expressing different Vbeta elements may play different roles in regulating the airway inflammation in asthma.

Asthma↗
PubMed2002

Simultaneous analysis of T cell clonality and cytokine production in rheumatoid arthritis using three-colour flow cytometry.

In this study we examined the cytokine production by T cells and TCRVbeta subsets in peripheral blood (PB) and synovial fluid (SF) from six RA patients and PB from 10 normal subjects, using three-colour flow cytometry. In two RA subjects we assessed T cell clonality by RT PCR using TCRBV family-specific primers and analysed the CDR3 (complementarity determining region 3) length by GeneScan analysis. A high percentage of IFN-gamma- and IL-2- producing cells was observed among the PB T cells in both the RA patients and normal controls and among the SF T cells in RA patients. In contrast, the percentage of T cells producing IL-4 and IL-5 was small among PB T cells in both RA patients and normal controls and among SF T cells in RA patients. There was no significant difference in the production of IFN-gamma, IL-2 and IL-5 between the two compartments (PB and SF); however, there were significantly more IL-4-producing cells in SF. Molecular analysis revealed clonal expansions of four TCRBV families in SF of two of the RA patients studied: TCRBV6.7, TCRBV13.1 and TCRBV22 in one and TCRBV6.7, TCRBV21.3 and TCRBV22 in the second. These expansions demonstrated cytokine expression profiles that differed from total CD3+ cells, implying that T cell subsets bearing various TCR-Vbeta families may have the potential to modulate the immune response in RA patients.

Adult↗
PubMed2002

DNA ploidy and S-phase fraction analyses of hyperplastic, atypical and cancerous endometrium using flow cytometry from paraffin-embedded tissues.

Atypical hyperplasia of the endometrium is an entity that needs to be clearly distinguished from other florid hyperplastic states on the one hand and from well-differentiated adenocarcinomas on the other. This may at times be difficult on pure morphological grounds. In this study, DNA ploidy and S-phase fraction of hyperplastic, atypical and cancerous endometrium were evaluated using flow cytometry from paraffin-embedded tissues. In total, 72 cases (24 hyperplastic, 24 atypical and 24 adenocarcinomas) were selected. All hyperplastic endometria showed a diploid stemline, while 2/24 atypical hyperplasias showed aneuploid (Near-diploid) peaks. Both of these cases were severely atypical and one of these, on hysterectomy, showed early invasive carcinoma. There was no significant difference in mean S-phase fractions of hyperplastic vs. atypical endometria. DNA aneuploidy was significantly more common with much higher S-phase fractions in poorly and moderately differentiated carcinomas than in well-differentiated ones. It was concluded that aneuploid (near-diploid) peaks, if ever present in atypical hyperplasias, may indicate an aggressive disease/neoplastic transformation.

Adenocarcinoma↗
PubMed2001

Locally critical quantum phase transitions in strongly correlated metals.

When a metal undergoes a continuous quantum phase transition, non-Fermi-liquid behaviour arises near the critical point. All the low-energy degrees of freedom induced by quantum criticality are usually assumed to be spatially extended, corresponding to long-wavelength fluctuations of the order parameter. But this picture has been contradicted by the results of recent experiments on a prototype system: heavy fermion metals at a zero-temperature magnetic transition. In particular, neutron scattering from CeCu6-x Aux has revealed anomalous dynamics at atomic length scales, leading to much debate as to the fate of the local moments in the quantum-critical regime. Here we report our theoretical finding of a locally critical quantum phase transition in a model of heavy fermions. The dynamics at the critical point are in agreement with experiment. We propose local criticality to be a phenomenon of general relevance to strongly correlated metals.

Journal Article↗
PubMed2001

Molecular characterization of calmodulin trapping by calcium/calmodulin-dependent protein kinase II.

Autophosphorylation of alpha-Ca(2+)/calmodulin-dependent protein kinase II (CaM kinase II) at Thr(286) results in calmodulin (CaM) trapping, a >10,000-fold decrease in the dissociation rate of CaM from the enzyme. Here we present the first site-directed mutagenesis study on the dissociation of the high affinity complex between CaM and full-length CaM kinase II. We measured dissociation kinetics of CaM and CaM kinase II proteins by using a fluorescently modified CaM that is sensitive to binding to target proteins. In low [Ca(2+)], the phosphorylated mutant kinase F293A and the CaM mutant E120A/M124A exhibited deficient trapping compared with wild-type. In high [Ca(2+)], the CaM mutations E120A, M124A, and E120A/M124A and the CaM kinase II mutations F293A, F293E, N294A, N294P, and R297E increased dissociation rate constants by factors ranging from 2.3 to 116. We have also identified residues in CaM and CaM kinase II that interact in the trapped state by mutant cycle-based analysis, which suggests that interactions between Phe(293) in the kinase and Glu(120) and Met(124) in CaM specifically stabilize the trapped CaM-CaM kinase II complex. Our studies further show that Phe(293) and Asn(294) in CaM kinase II play dual roles, because they likely destabilize the low affinity state of CaM complexed to unphosphorylated kinase but stabilize the trapped state of CaM bound to phosphorylated kinase.

Adenosine Triphosphate↗
PubMed2001

Large harmonic softening of the phonon density of states of uranium.

Phonon density-of-states curves were obtained from inelastic neutron scattering spectra from the three crystalline phases of uranium at temperatures from 50 to 1213 K. The alpha-phase showed an unusually large thermal softening of phonon frequencies. Analysis of the vibrational power spectrum showed that this phonon softening originates with the softening of a harmonic solid, as opposed to vibrations in anharmonic potentials. It follows that thermal excitations of electronic states are more significant thermodynamically than are the classical volume effects. For the alpha-beta and beta-gamma phase transitions, vibrational and electronic entropies were comparable.

Journal Article↗
PubMed2001

Sequential monitoring of peripheral T-lymphocyte cytokine gene expression in the early post renal allograft period.

BACKGROUND: Despite numerous studies, the precise role of cytokines in acute renal allograft rejection remains unclear. In this study we have monitored sequential changes in peripheral T cell cytokine gene expression, correlating the changes with clinical events after adult renal transplantation, to provide a deeper insight of the role of cytokines in allograft rejection. METHODS: Sequential changes in peripheral Th-1 [interleukin- (IL) 2 and interferon-gamma] and Th-2 (IL-4, IL-5, IL-10, and IL-13) cytokine gene expression in 43 patients with (n=15) and without (n=28) episodes of biopsy-proven rejection was monitored in the first 6 weeks after renal transplantation using a sensitive, semi-quantitative reverse-transcriptase polymerase chain reaction ELISA approach. RESULTS: Th-2 cytokines: IL-5 and IL13 expression increased before and during acute rejection, and decreased after successful antirejection therapy. A significant fall in IL-4 expression after transplantation and subsequent return to its baseline level of expression was observed in both nonrejectors and rejectors. IL-10 showed persistently high expression in nonrejectors, but in rejectors the expression fell during acute rejection, with a subsequent rise after antirejection therapy. Th-1 cytokines: IL-2 and IFN-gamma decreased in expression in the first week posttransplant in the rejectors, at the time of acute rejection (IL-2 only) and immediately after completion of antirejection therapy. CONCLUSIONS: Sequential monitoring of peripheral T cell cytokine gene expression after renal transplantation detected changes in expression that correlated with episodes of acute rejection and response to antirejection therapy. This approach may be applicable in the clinical laboratory for monitoring posttransplant changes in T cell alloreactivity and immunosuppression.

Adult↗
PubMed2001

The PRT protein family.

Members of the homologous PRT family are catalytic and regulatory proteins involved in nucleotide synthesis and salvage. New crystal structures have revealed key elements of PRT protein function, as well as glimpses of how the fold has evolved to perform both catalytic and regulatory functions.

ATP Phosphoribosyltransferase↗
PubMed2001

Lipid peroxidation in hepatic steatosis in humans is associated with hepatic fibrosis and occurs predominately in acinar zone 3.

BACKGROUND AND AIMS: Hepatic steatosis has been shown to be associated with lipid peroxidation and hepatic fibrosis in a variety of liver diseases including non-alcoholic fatty liver disease. However, the lobular distribution of lipid peroxidation associated with hepatic steatosis, and the influence of hepatic iron stores on this are unknown. The aim of this study was to assess the distribution of lipid peroxidation in association with these factors, and the relationship of this to the fibrogenic cascade. METHODS: Liver biopsies from 39 patients with varying degrees of hepatic steatosis were assessed for evidence of lipid peroxidation (malondialdehyde adducts), hepatic iron, inflammation, fibrosis, hepatic stellate cell activation (alpha-smooth muscle actin and TGF-beta expression) and collagen type I synthesis (procollagen alpha1 (I) mRNA). RESULTS: Lipid peroxidation occurred in and adjacent to fat-laden hepatocytes and was maximal in acinar zone 3. Fibrosis was associated with steatosis (P < 0.04), lipid peroxidation (P < 0.05) and hepatic iron stores (P < 0.02). Multivariate logistic regression analysis confirmed the association between steatosis and lipid peroxidation within zone 3 hepatocytes (P < 0.05), while for hepatic iron, lipid peroxidation was seen within sinusoidal cells (P < 0.05), particularly in zone 1 (P < 0.02). Steatosis was also associated with acinar inflammation (P < 0.005). alpha-Smooth muscle actin expression was present in association with both lipid peroxidation and fibrosis. Although the effects of steatosis and iron on lipid peroxidation and fibrosis were additive, there was no evidence of a specific synergistic interaction between them. CONCLUSIONS: These observations support a model where steatosis exerts an effect on fibrosis through lipid peroxidation, particularly in zone 3 hepatocytes.

Actins↗
PubMed2001

Modification of T-cell receptor Vbeta repertoire in response to allergen stimulation in peanut allergy.

BACKGROUND: Peanut is one of the most common foods causing allergic reactions and is the most common cause of fatal and near-fatal food-related anaphylaxis. Little is known of the immunologic mechanisms that underlie peanut allergy. OBJECTIVES: In this study we examined clonality of the T-cell response (TCR) to peanut in MHC class II identical, peanut allergy-discordant sibling pairs. METHODS: Four sibling pairs were investigated. The TCR repertoire was analyzed before and after in vitro stimulation of PBMCs with crude peanut or PHA, as control for general/nonspecific reactivity. Eighteen TCR-Vbeta families were examined by flow cytometry. Where significant differences in incidence of particular TCR-Vbeta families were observed, PCR familyspecific cDNA amplification and gene scanning were performed. RESULTS: After stimulation with peanut, no selective expansion of any TCR-Vbeta subpopulation was observed with flow cytometry, in either the peanut-allergic or nonallergic siblings, with the exception of 1 peanut-allergic subject who demonstrated a significant increase of TCR-Vbeta11(+) cells (0.3%-5.9% of the total CD3(+) cells). However, gene scanning revealed predominant single-size PCR products for TCRBV11 in all peanut-allergic subjects after peanut stimulation. TCRBV11 polyclo-nality was observed in allergic and nonallergic subjects before peanut stimulation and in nonallergic subjects after peanut stimulation. In comparison, all subjects, before and after stimulation with peanut, showed polyclonality for TCRBV2. CONCLUSIONS: Our results argue for clonal or oligoclonal TCRs to crude peanut and indicate that changes in the TCRBV11 subpopulation are restricted to peanut-allergic subjects after stimulation with crude peanut allergen.

Allergens↗
PubMed2001

Right-sided asymmetry in sensitivity to tickle.

A standard tickle apparatus was used to apply stimuli to the soles of left and right feet of subjects. Subject ratings of the strength of the tickle sensation felt after each stimulus revealed that the right foot was significantly more sensitive than the left. This effect was independent of both hand and foot preference. The results are discussed in relation to other findings on lateralisation, and it is suggested that they are consistent with evidence that the left hemisphere is more involved in positive emotions.

Journal Article↗
PubMed2001

Resolving disparities in antidepressant treatment and quality-of-life outcomes between uninsured and insured primary care patients with depression.

BACKGROUND: Efforts to improve primary care depression treatment should penetrate to vulnerable uninsured populations. OBJECTIVE: To assess a primary care intervention's impact on treatment and quality-of-life outcomes in uninsured and insured depressed patients during the acute treatment phase. RESEARCH DESIGN: Twelve community primary care practices were randomized to 'enhanced' (intervention) and usual care conditions. Physicians, nurses and administrative staff in enhanced care practices received training to improve detection and management of depression. SUBJECTS: In 1996 to 1997, 383 nonelderly depressed patients who were either uninsured or covered by private insurance/Medicaid were enrolled; 343 (89.6%) completed six-month follow-up. MEASURES: Adequate pharmacotherapy (>or=3 months of antidepressants at therapeutic doses); adequate psychotherapy (>or=8 counseling visits); improvement in mental-health-related-quality-of-life (MHQOL), assessed by Mental Component Summary scale for SF-36. RESULTS: Multivariate results showed that 54.6% of uninsured enhanced care (UEC) patients received adequate pharmacotherapy, compared with 14.3% of uninsured usual care (UUC) patients (P = 0.0005); however, receipt of adequate psychotherapy was comparable between these two groups (18.2% UEC, 11.9% UUC; P = 0.42). Intervention effects on insured patients' treatment were modest to minimal. Among usual care patients, the insured had 5.4 points greater improvement in MHQOL at 6 months than the uninsured (12.4 points insured, 7.0 points uninsured; P = 0.02); however, among patients receiving the intervention, the insured and uninsured had comparable MHQOL improvement (12.3 points insured, 11.6 points uninsured; P = 0.76). CONCLUSIONS: The intervention improved antidepressant treatment rates in uninsured patients and helped resolve quality-of-life outcome disparities observed between insured and uninsured patients receiving usual care.

Adult↗
PubMed2001

Lipoprotein lipase gene mutations and the genetic susceptibility of preeclampsia.

In the pathogenesis of preeclampsia, endothelial cell activation or dysfunction is a central theme, and marked dyslipidemia may contribute to endothelial cell dysfunction. The objective of this study was to evaluate the association between preeclampsia and mutations within the lipoprotein lipase (LPL) gene. DNA was extracted from whole blood or cheek swabs of 250 preeclamptic patients, 265 control subjects, and 106 offspring of preeclamptic patients (all white). Control subjects were women who had undergone >/=2 term pregnancies unaffected by preeclampsia. All samples were genotyped for 3 LPL polymorphisms with the use of polymerase chain reaction of known allelic variants. The 3 mutations studied were the following: (1) Asp9Asn substitution in exon 2, (2) T-to-G substitution at position -93 of the proximal promotor region (-93T/G), and (3) Asn291Ser substitution in exon 6. Results were analyzed with an chi(2) contingency table. The prevalences of the Asp9Asn mutation, -93T/G promotor mutation, and Asn291Ser mutation were not significantly different among the preeclamptic patients and control subjects (Asp9Asn: patients, 2.8%; control subjects, 4.0%; -93T/G: patients, 4.5%; control subjects, 5.5%; Asn291Ser: patients, 4.0%; control subject, 3.0%). In addition, there was no difference in the frequency of any of the mutations in the offspring of preeclamptic women compared with that observed in the control population. Between a small group of patients with nulliparous HELLP syndrome (a variant of severe preeclampsia: hemolysis, elevated liver enzyme, low platelets) patients (n=12) and control subjects, there was a significant difference in the prevalence of the Asn291Ser mutation (16.7% versus 3.0%, P=0.01). In this large white population, the Asp9Asn mutation, -93T/G promotor mutation, and Asn291Ser mutation were not associated with an increased risk for preeclampsia. In a small subgroup of patients, the Asn291Ser mutation was associated with an increased risk for nulliparous HELLP syndrome.

Female↗
PubMed2001

Retail fast foods: overview of safe sandwich manufacture.

The manufacture of sandwiches on a large scale for purchase at retail outlets is anything but simple. There are many quality, safety and hygiene processes that must be taken into account before, during and after production. A manufacturer must be sure of the requirements for quality and safety to determine suitable suppliers, methods of assembly, packaging, and distribution methods. Procedures must be in place throughout production to ensure safe food is being offered for sale to the consumer. Some of the steps to assure good quality include Hazard Analysis Critical Control Points and temperature control, both of which are legal requirements and implementing good manufacturing practice. There are strict legal requirements for labelling that have to be followed. This article concludes that safe sandwich manufacture on a large scale is a very complex process incorporating many hygiene, safety and legal requirements.

Commerce↗
PubMed2001

Is glucagonoma of the pancreas a curable disease?

BACKGROUND: Glucagonomas are rare neuroendocrine tumors of the pancreas. Because of its rarity, its natural history is not well understood. AIM: We evaluated the natural history of glucagonomas treated at a tertiary care cancer center. METHODS: A retrospective analysis of 12 patients during 1970 to 2000 was performed. Six patients (50%) had a tumor located in the head of the pancreas. RESULTS: Abdominal pain (83%) and weight loss (75%) were the most common symptoms. Median tumor size was 6 cm (range 0.04-10). Seven patients (58%) had liver metastases. Five patients (42%) underwent curative resection. Overall median survival was 66 mo, and 5-yr overall survival was 66%. Five-yr overall survival was 83% for patients who had resection versus 50% for the non-resected patients (p = 0.04). Patients who were disease-free had a complete resection of the primary tumor and no liver involvement. CONCLUSIONS: Glucagonomas generally present with liver metastases at the time of diagnosis. Cure is only possible if the disease is localized and completely resected.

Adult↗
PubMed2001

A review of hepatitis E virus.

Hepatitis E virus (HEV) is a major cause of outbreaks and sporadic cases of viral hepatitis in tropical and subtropical countries but is infrequent in industrialized countries. The virus is transmitted by the fecal-oral route with fecally contaminated drinking water being the usual vehicle. Hepatitis resulting from HEV infection is a moderately severe jaundice that is self-limiting in most patients. Young adults, 15 to 30 years of age, are the main targets of infection, and the overall death rate is 0.5 to 3.0%. However, the death rate during pregnancy approaches 15 to 25%. Death of the mother and fetus, abortion, premature delivery, or death of a live-born baby soon after birth are common complications of hepatitis E infection during pregnancy. Hepatitis E virus is found in both wild and domestic animals; thus, HEV is a zoonotic virus. The viruses isolated from swine in the United States or Taiwan are closely related to human HEV found in those areas. The close genetic relationship of the swine and human virus suggests that swine may be a reservoir of HEV. In areas where swine are raised, swine manure could be a source of HEV contamination of irrigation water or coastal waters with concomitant contamination of produce or shellfish. Increasing globalization of food markets by industrialized countries has the potential of introducing HEV into new areas of the world. The purpose of this review is to cover certain aspects of hepatitis E including the causative agent, the disease, diagnosis, viral detection, viral transmission, epidemiology, populations targeted by HEV, and the role of animals as potential vectors of the virus.

Animals↗