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Biomedical subjects

J K Smith

Publications and source records attributed to J K Smith.

At least 37 records · Page 2Linked to original sources
PubMed1999

Long-term exercise and atherogenic activity of blood mononuclear cells in persons at risk of developing ischemic heart disease.

CONTEXT: Increasing evidence demonstrates that atherosclerosis is an immunologically mediated disease in which the secretion of atherogenic and atheroprotective cytokines, by infiltrating blood mononuclear cells, plays an important role. It is not known whether long-term exercise alters this atherogenic and atheroprotective activity directly. OBJECTIVE: To determine the effect of long-term exercise on the atherogenic activity of blood mononuclear cells in persons at risk of developing ischemic heart disease. DESIGN: Before-after trial using a 6-month individualized, supervised exercise program, with an enrollment period from December 1996 to October 1997. SETTING: Hospital-based community wellness center. PARTICIPANTS: Of 110 persons who responded to a public request for volunteers, 52 met the inclusion criteria (risk ratio for myocardial infarction > or =1.7 based on serum complement and/or C-reactive protein levels, and normal exercise treadmill test results). Forty-three of the 52 enrollees (25 women [mean age, 49.7 years] and 18 men [mean age, 48.1 years]) completed the study; 9 withdrew for personal reasons. Additional risk factors for ischemic heart disease included hypercholesterolemia (65.1 %), a family history of coronary heart disease (62.8%), inactivity (60.5%), hypertension (32.6%), obesity (25.6%), smoking (11.6%), and diabetes mellitus (4.7%). MAIN OUTCOME MEASURES: Blood levels were compared at baseline and after the exercise program had been completed for the following: spontaneous and phytohemagglutinin-induced production of interleukin 1 alpha, tumor necrosis factor alpha, and interferon gamma (atherogenic cytokines), and interleukin 4, interleukin 10, and transforming growth factor beta 1 (atheroprotective cytokines) by blood mononuclear cells; lymphocyte phenotypes and mitogenic responses to phytohemagglutinin; and serum C-reactive protein levels. RESULTS: Subjects exercised for a mean of 2.5 (range, 0.3-7.4) hours per week. Mononuclear cell production of atherogenic cytokines fell by 58.3 % (P<.001) following the exercise program, where as the production of atheroprotective cytokines rose by 35.9% (P<.001). Changes in transforming growth factor beta 1 and in phytohemagglutinin-induced atherogenic cytokine production after the exercise program were proportionate to the time subjects spent performing repetitive lower-body motion exercises (P<.02), indicating a dose-response relationship. After the exercise program, changes in cellular function were reflected systemically by a 35% decrease in serum levels of C-reactive protein (P=.12). CONCLUSIONS: Our data suggest that long-term exercise decreases the atherogenic activity of blood mononuclear cells in persons at risk of developing ischemic heart disease. This may be a mechanism whereby physical activity protects against ischemic heart disease.

Arteriosclerosis↗
PubMed1999

Structural changes in the recombinant, NADP(H)-binding component of proton translocating transhydrogenase revealed by NMR spectroscopy.

We have analysed 1H, 15N-HSQC spectra of the recombinant, NADP(H)-binding component of transhydrogenase in the context of the emerging three dimensional structure of the protein. Chemical shift perturbations of amino acid residues following replacement of NADP+ with NADPH were observed in both the adenosine and nicotinamide parts of the dinucleotide binding site and in a region which straddles the protein. These observations reflect the structural changes resulting from hydride transfer. The interactions between the recombinant, NADP(H)-binding component and its partner, NAD(H)-binding protein, are complicated. Helix B of the recombinant, NADP(H)-binding component may play an important role in the binding process.

Amino Acid Sequence↗
PubMed1999

Oral use of interferon-alpha stimulates ISG-15 transcription and production by human buccal epithelial cells.

ISG-15 is a 15-kDa protein encoded by an interferon (IFN)-stimulated gene (ISG), which is transcriptionally regulated by IFN-alpha and IFN-beta. Considered as part of the cytokine network, ISG-15 has the potential to amplify the immunomodulatory effects of these IFNs by enhancing IFN-gamma production, natural killer cell proliferation, and lymphokine-alphactivated killer cell cytotoxicity. To understand better the mechanism(s) of action of orally administered IFN-alpha, we have studied the effect of IFN-alpha on ISG-15 gene expression by human buccal epithelial cells (BEC). For in vitro studies, ISG-15 mRNA and protein levels were measured in BEC incubated for 0.5, 2, and 9 h with 100 or 1,000 IU/ml of human lymphoblastoid IFN-alpha. For in vivo studies, ISG-15 mRNA was measured in BEC samples collected at baseline, and 0.5, 2, and 9 h after 5-20 min of oral rinsing with 10 ml of IFN-alpha (1,000 IU/ml). ISG-15 mRNA was measured by reverse transcriptase polymerase chain reaction (RT-PCR), and ISG-15 protein production by Western Blot analysis. IFN-alpha augmented BEC ISG-15 gene expression in a concentration dependent manner both in vivo and in vitro. We conclude that orally administered IFN-alpha exerts its immunomodulatory effects in humans in part by upregulating the production of ISG-15 by BEC, thereby enhancing the immune reactivity of mucosa-associated lymphocytes.

Adjuvants, Immunologic↗
PubMed1999

Interferon-alpha upregulates gene expression of aquaporin-5 in human parotid glands.

Aquaporins are a family of homologous membrane proteins that function as highly selective water channels. Aquaporin-5 (AQP5) is uniquely present in lacrimal and salivary glands, where it accounts for normal tear and saliva production. We tested the hypothesis that orally administered human interferon-alpha (HuIFN-alpha) benefits persons with xerostomia by augmenting the production of AQP5 protein by parotid gland epithelium. Cells from three human parotid glands were cultured with and without human lymphoblastoid IFN-alpha, and assayed for AQP5 mRNA levels by reverse transcriptase polymerase chain reaction (RT-PCR), and AQP5 protein levels by Western blot. Intracellular localization of AQP5 protein was done using confocal microscopy. The functional integrity of the glandular tissue was confirmed by RT-PCR analysis of alpha-amylase 1 and basic proline-rich protein transcripts. AQP5 was constitutively expressed in human parotid gland tissue, with AQP5 protein restricted to the plasma membranes and cytoplasmic vesicles of acinar cells. IFN-alpha augmented AQP5 transcription and protein production in a concentration-dependent manner, and increased the size of intensity of staining of AQP5-containing cytoplasmic vesicles in acinar cells. We conclude that IFN-alpha upregulates AQP5 gene expression in human parotid acinar cells in vitro. To our knowledge, this is the first demonstration that IFN-alpha regulates the gene expression of an aquaporin.

Administration, Oral↗
PubMed1999

Human endothelium as a source of multifunctional cytokines: molecular regulation and possible role in human disease.

Endothelial cells, by virtue of their capacity to express adhesion molecules and cytokines, are intricately involved in inflammatory processes. Endothelial cells have been shown to express interleukin-1 (IL-1), IL-5, IL-6, IL-8, IL-11, IL-15, several colony-stimulating factors (CSF), granulocyte-CSF (G-CSF), macrophage CSF (M-CSF) and granulocyte-macrophage CSF (GM-CSF), and the chemokines, monocyte chemotactic protein-1 (MCP-1), RANTES, and growth-related oncogene protein-alpha (GRO-alpha). IL-1 and tumor necrosis factor-alpha (TNF-alpha) produced by infiltrating inflammatory cells can induce endothelial cells to express several of these cytokines as well as adhesion molecules. Induction of these cytokines in endothelial cells has been demonstrated by such diverse processes as hypoxia and bacterial infection. Recent studies have demonstrated that adhesive interactions between endothelial cells and recruited inflammatory cells can also signal the secretion of inflammatory cytokines. This cross-talk between inflammatory cells and the endothelium may be critical to the development of chronic inflammatory states. Endothelial-derived cytokines may be involved in hematopoiesis, cellular chemotaxis and recruitment, bone resorption, coagulation, and the acute-phase protein synthesis. As many of these processes are critical to the maturation of an inflammatory and reparative state, it appears likely that endothelial-derived cytokines play a crucial role in several diseases, including atherosclerosis, graft rejection, asthma, vasculitis, and sepsis. Genetic and pharmacologic manipulation of endothelial-derived cytokines provides an additional approach to the management of chronic inflammatory diseases.

Arteriosclerosis↗
PubMed1999

INR elevation associated with diarrhea in a patient receiving warfarin.

OBJECTIVE: To report a case of international normalized ratio (INR) prolongation in a patient receiving warfarin who experienced several episodes of diarrhea. CASE SUMMARY: A 56-year-old white woman, previously controlled on warfarin therapy (INR 2.5-3.5) after aortic valve replacement, experienced six episodes of INR elevation, each associated with an acute bout of diarrhea lasting from one to four days. The patient had not received additional warfarin or new medications (including nonprescription medications and herbal remedies) prior to the episodes. The patient had no obvious signs of bleeding (except bruising on 1 episode) or signs of infection determined through physician evaluation of the patient and her stools. In addition, she had no diagnosis of liver disease or acute or chronic malabsorption. The patient did report that her dietary intake decreased to 25-50% of normal during these episodes of diarrhea, which may result in decreased vitamin K ingestion. DISCUSSION: This is one of the first case reports documenting a trend of INR elevation specifically with episodes of diarrhea. Since most of the common reasons for acute INR elevation have been eliminated, diarrhea with decreased oral intake are the most probable causes for these observed changes in the INR. Several reports suggest that acute diarrhea results in malabsorption of vitamin K, which can predispose patients taking warfarin to INR elevations, but in many of these reports patients had other risk factors for INR elevation. Although the effect of diarrhea on vitamin K absorption and the INR is difficult to quantify, the INR elevation reported here seemed to be directly associated with the duration of each diarrheal episode. CONCLUSIONS: Diarrhea episodes in patients receiving warfarin can result in prolongation of the INR and possible bleeding. Patients who experience diarrhea or decreased oral intake resulting in elevated INRs should have their INRs evaluated more frequently and their warfarin doses adjusted appropriately.

Acute Disease↗
PubMed1999

Pancreas divisum: implications for diagnostic and therapeutic pancreatography.

OBJECTIVE: The purpose of our study was to determine the prevalence, distribution, and clinical significance of pancreatic ductal changes due to pancreatitis on ERCP in patients with pancreas divisum. MATERIALS AND METHODS: From January 1993 through December 1997, 1714 patients underwent 2469 ERCP studies. Ninety-four patients (5.5%) had pancreas divisum. Retrospective review of the spot radiographs was performed to establish the presence and location of pancreatitis. Clinical indications for and therapy during ERCP were correlated with radiographic findings. RESULTS: Of the 94 patients with pancreas divisum, 54 (57%) had radiographic evidence of pancreatitis. Of these 54 patients, 44 had at least one episode of clinically documented pancreatitis, seven had recurrent abdominal pain, and three underwent ERCP for biliary indications. In 76% of the 54 patients with radiographic evidence of pancreatitis, only the dorsal system showed irreversible inflammatory change (p < .0001). Acute recurrent pancreatitis was the most common indication for ERCP in divisum patients and was statistically more common than in pancreatitis patients with normal anatomy (p < .0001). Sixty-two (66%) of the 94 patients with pancreas divisum underwent endoscopic pancreatic intervention, most commonly minor papilla sphincterotomy or stenting or both. Eleven patients with clinically documented pancreatitis had no abnormalities revealed by ERCP. CONCLUSION: In our population of patients referred for ERCP and found to have pancreas divisum, the prevalence of pancreatitis was very high and usually was limited to a dorsal distribution.

Acute Disease↗
PubMed1999

Doppler sonographic enhancement of hepatic hemangiomas and hepatocellular carcinomas after perflenapent emulsion: preliminary study.

Ultrasonographic microbubble contrast agents improve Doppler signals by increasing blood backscatter. We retrospectively reviewed our experience with perflenapent (EchoGen), an emulsion of liquid dodecafluoropentane, in the evaluation of 13 patients with focal hepatic lesions (10 hemangiomas and six hepatocellular carcinomas). Perflenapent improved the detection of color Doppler flow signals within the lesions. The hemangiomas showed peripheral nonpulsatile signals and the hepatocellular carcinomas showed more diffuse enhancement with both arterial and venous type signals. This preliminary study suggests that perflenapent administration may aid in the sonographic differentiation of these focal lesions.

Adult↗
PubMed1999

Imaging of soft tissue sarcomas.

Imaging of soft tissue sarcomas is critically important in the management of these patients. Whether CT scanning or MR imaging is the best test remains controversial; studies to support either modality exist and are reviewed. An integrated approach using clinical algorithms and radiologic studies to preoperatively stage and follow these patients seems to provide optimal care.

Abdominal Neoplasms↗
PubMed1998

Spectral measurements of intercalated PCR-amplified short tandem repeat alleles.

Short tandem repeat (STR) alleles are popular for use as forensic markers due to their highly polymorphic nature. Commonly they are separated by gel electrophoresis and visualized using intercalation dyes. The purpose of this study was to determine the changes in absorbance and fluorescence of DNA-intercalation dye complexes as a function of base pair (bp)-to-dye ratio. The DNA samples consisted of STR alleles from loci THO1, F13A01, and vWFA31. The alleles were PCR amplified and HPLC purified to ensure that only the desired DNA fragment was present in each sample. Alleles ranged in size from 151 bp for locus vWFA (allele 17) to 199 bp for the locus F13A01 (allele 8). The adenine and thymine (AT) content varied from 48% for the THO1 locus to 69% for F13A01 and vWFA31 loci. The homozygous alleles of each locus were mixed individually with the bis-intercalators TOTO-1 and YOYO-1 and their corresponding monomeric dyes TOPRO-1 and YOPRO-1. The absorbance of the DNA-dye complex at 260 nm increased with addition of each intercalation dye. Subtraction of the dye absorbance rendered the DNA absorbance constant at 260 nm. Fluorescence emission increased dramatically upon intercalation of both the monomeric and dimeric dyes into the DNA helix. A plateau of fluorescence intensity was observed at base pair-to-dye ratios of 10/1 for the bis-intercalator TOTO-1 and 5/1 for YOYO-1 for all three loci. The greatest fluorescence intensity response was obtained with the intercalator YOYO-1 using allele 8 of the F13A01 locus, which had the greatest AT concentration.

Adenine↗
PubMed1998

Sequencing using capillary electrophoresis of short tandem repeat alleles separated and purified by high performance liquid chromatography.

Polymerase chain reaction (PCR) amplified alleles need to be isolated and purified before carrying out additional analysis to confirm sequence, number of repeats and microvariants within a short tandem repeat (STR) locus. Also, PCR amplification of tetranucleotide repeat loci, used in DNA typing assays, often result in heteroduplex formation, adding to the complexity of analysis. Sequencing reactions require single specific target DNA for reliable sequencing analysis. Alkylated poly(styrene-divinylbenzene) columns at elevated temperature and gradient elution conditions increase the efficiency of separation to allow for the purification of PCR products. Using the separation technique of ion-pairing reverse-phase (IPRP) high performance liquid chromatography (HPLC), molecular biologists can separate and purify DNA fragments without alteration to the double-stranded DNA sequencing properties. In this study, the IP-RP chromatography technique has been demonstrated by separation of alleles of the short tandem repeat loci of TH01, vWA31, F13A01 and FES/ FPS. Alleles differing in size range of 12 to 4 base pairs were separated by IPRP/HPLC and individual alleles were peak-captured, then cycle-sequenced. These HPLC fractions required no additional steps prior to cycle sequencing. Capillary electrophoresis (CE) was used to sequence the alleles. Furthermore, CE offers advantages over traditional slab methods via automation and higher applied voltages. Interestingly, unlike traditional gel electrophoresis, samples were introduced into the sieving matrix by electrokinetic injection, which allows for multiple injections from a single sample, a key feature for method development. Applied voltage was 320 V per centimeter using a nonderivatized fused silica capillary with an interior diameter of 50 microm and a total length of 47 centimeters. The total analysis time including capillary filling and pre-electrophoresis was less than 30 min for a 220-bp fragment. A sequencing rate of 530 bp/h was achieved using these conditions. By combining the techniques of HPLC separation and CE sequencing, the results confirmed the sequence and number of nucleotide repeats for each STR loci. An average sequencing efficiency of 97% was achieved. Additionally, this method defined the absence of a 9.3 microvariant for a TH01 heterozygous individual previously typed as a 9, 9.3/10 using slab gel electrophoresis. The techniques described can be applied to other DNA purification and isolation problems.

Alleles↗
PubMed1998

Multifunctional cytokine expression by human coronary endothelium and regulation by monokines and glucocorticoids.

Human endothelium is capable of expressing a variety of molecules, including cytokines and growth factors, critical to inflammation. This aspect of coronary endothelium has not been studied in detail. In this study, we report, for the first time, expression of multifunctional cytokines by human coronary artery endothelial cells (HCAEC) and their regulation by inflammatory cytokines and glucocorticoids. We also compared expression of cytokine transcripts in two additional cell lines derived from pulmonary artery (HPAEC) and umbilical vein (HUVEC) endothelium. HCAEC expressed transcripts for interleukin 5 (IL-5), IL-6, IL-8, and monocyte chemotactic protein-1 (MCP-1) constitutively. Induction of IL-1alpha, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), and MCP-1 was seen following treatment with TNFalpha. We found no expression of IL-1RA, IL-2, IL-4, IL-13, TNF-alpha, or IFN-gamma in HCAEC. IL-1beta and TNF-alpha synergistically induced IL-6 and GM-CSF and additively induced IL-8 and MCP-1 production, while IL-2, IL-10, IFN-alpha, and IFN-gamma had little or no additional effects. Interestingly, no IL-1alpha or IL-5 protein product was found even after maximal stimulation of HCAEC. No significant differences were seen in the profile of cytokine genes expressed by HCAEC, HPAEC, or HUVEC. Glucocorticoids inhibited IL-8 production from all three cell lines. This study demonstrates that human coronary endothelial cells are capable of expressing a wide variety of multifunctional cytokines which may be of relevance to vascular inflammation.

Cell Line↗
PubMed1998

The influence of postweaning housing conditions on drug-induced conditioned taste aversion.

Postweaning social isolation can influence the sensitivity of rats to several effects of drugs of abuse. The present study investigated the influence of postweaning housing conditions on the sensitivity of rats to the aversive effects of a number of psychoactive agents using a conditioned taste aversion (CTA) test procedure. Development of a CTA was assessed by pairing administration of the drug with the consumption of a 0.05% (weight/volume) saccharin solution in water-deprived (18 h) rats in a 20 min drinking period. Saccharin consumption was then measured in 20 min test sessions over the next 4 consecutive days. Consumption of saccharin solution was significantly reduced in both isolated and enriched rats following administration of d-amphetamine (2 mg/kg), cocaine (30 mg/kg), morphine (10 mg/kg), nicotine (1.0 mg/kg), caffeine (20 mg/kg), alcohol (1.5 g/kg), and LiCl (0.15 M, 4 ml/kg). There was no significant effect of housing conditions on the CTA induced by cocaine, nicotine, alcohol, or LiCl; however, isolation-reared rats were found to be less sensitive to the aversive effects of d-amphetamine, morphine, and caffeine in this paradigm. These results suggest that rearing rats in social isolation induces an attenuation in sensitivity to the aversive effects of some psychoactive agents.

Animals↗
PubMed1998

Hysterosalpingography with videofluoroscopy: effect on radiologic practice in an academic medical center.

RATIONALE AND OBJECTIVES: The authors attempted to determine whether videotaping the fluoroscopic portion of hysterosalpingography would result in changed diagnoses or an increase in diagnostic confidence. MATERIALS AND METHODS: Ninety-nine consecutive outpatients underwent routine hysterosalpingography. The fluoroscopic portion of the examination was captured on videotape. Two consecutive interpretations of each hysterosalpingogram were made by attending radiologists. First, spot radiographs were interpreted alone. Second, these images were viewed along with videofluoroscopy. Concordance of and confidence in findings for the two interpretations were assessed with the two-tailed Fisher exact test. RESULTS: Interpretations of spot radiographs alone and with videofluoroscopy were in agreement in 92 of 99 uterine examinations and 164 of 198 tubal examinations. For uterine examinations classified as normal, interpretations of spot radiographs and videofluoroscopy were in agreement in 56 of 57 cases; there was no change in confidence with review of videofluoroscopic images. For uterine examinations interpreted as abnormal, agreement was noted in 36 of 42 cases (P = .04), and confidence increased with videofluoroscopy in 10 of 42 cases (P = .00001). With normal tubal findings, interpretations agreed in 94 of 118 cases, and confidence increased in 56 of 118 cases (P = .002). With abnormal tubal findings, interpretations agreed in 70 of 80 cases, and confidence increased in 20 of 80 cases (P = .002). When findings with and without videofluoroscopy were discordant, confidence was always higher after review of video-fluoroscopic images. CONCLUSION: Review of videofluoroscopic images obtained during hysterosalpingography increases the accuracy and confidence of diagnoses compared with review of spot radiographs alone.

Academic Medical Centers↗
PubMed1998

A PCR technique based on the Hip1 interspersed repetitive sequence distinguishes cyanobacterial species and strains.

The use of primers based on the Hip1 sequence as a typing technique for cyanobacteria has been investigated. The discovery of short repetitive sequence structures in bacterial DNA during the last decade has led to the development of PCR-based methods for typing, i.e., distinguishing and identifying, bacterial species and strains. An octameric palindromic sequence known as Hip1 has been shown to be present in the chromosomal DNA of many species of cyanobacteria as a highly repetitious interspersed sequence. PCR primers were constructed that extended the Hip1 sequence at the 3' end by two bases. Five of the 16 possible extended primers were tested. Each of the five primers produced a different set of products when used to prime PCR from cyanobacterial genomic DNA. Each primer produced a distinct set of products for each of the 15 cyanobacterial species tested. The ability of Hip1-based PCR to resolve taxonomic differences was assessed by analysis of independent isolates of Anabaena flos-aquae and Nostoc ellipsosporum obtained from the CCAP (Culture Collection of Algae and Protozoa, IFE, Cumbria, UK). A PCR-based RFLP analysis of products amplified from the 23S-16S rDNA intergenic region was used to characterize the isolates and to compare with the Hip1 typing data. The RFLP and Hip1 typing yielded similar results and both techniques were able to distinguish different strains. On the basis of these results it is suggested that the Hip1 PCR technique may assist in distinguishing cyanobacterial species and strains.

Bacterial Proteins↗
PubMed1998

Hemodialysis access graft stenosis: US detection.

PURPOSE: To prospectively evaluate the sensitivity of ultrasonography (US) in diagnosing stenosis of hemodialysis access grafts and their drainage veins in patients clinically suspected of having graft dysfunction. MATERIALS AND METHODS: Thirty-eight patients in whom dysfunction of their hemodialysis access grafts was suspected underwent both Doppler US and angiography. Gray-scale and color US were combined with spectral analysis of the graft, anastomoses, and venous outflow. Flow velocity at anastomoses and suspected stenotic areas was measured. The volume of flow in the graft was also measured. The prospective US criterion for diagnosis of stenosis was a focal twofold or higher elevation of peak systolic velocity (PSV) compared with the PSV immediately upstream. A blinded angiographic evaluation of the graft and drainage veins followed US. Angiographic diagnosis of stenosis required at least 50% narrowing in luminal diameter. US and angiographic results were then compared. RESULTS: Angiography allowed diagnosis of 43 stenoses in 34 patients. US depicted 92% (37 of 40) of these stenoses, with a 94% positive predictive value for any individual patient. Focal 2- to 2.9-times PSV elevation was associated with 75% or greater stenosis. Graft flow volume and resistive index change did not correlate with stenosis. CONCLUSION: US reliably depicts stenoses of hemodialysis access grafts and drainage veins in a clinically selected population when PSV criteria are used.

Adult↗