Isolation and characterization of a human glutathione S-transferase Ha1 subunit gene

We have isolated and characterized a human liver glutathione S-transferase Ha1 subunit gene. The gene spans approximately 12 kilobases and comprises seven exons separated by six introns. The transcription initiation site has been determined by primer extension analysis. A TATA box is located 26 nucleotides upstream from the transcription initiation site, an adenine residue. RNA blot analysis reveals that the gene is expressed at significantly higher levels in human liver than in HepG2 cells. The isolation and characterization of a human glutathione S-transferase Ha1 subunit gene should facilitate a detailed analysis of its transcriptional regulation.

Tomographic myocardial perfusion imaging with technetium-99m teboroxime during adenosine-induced coronary hyperemia: correlation with thallium-201 imaging

Single-photon emission computed tomographic imaging with technetium-99m teboroxime during exercise has been found to be feasible and the results correlate with those obtained with thallium-201. This study examined the feasibility of this technique and compared tomographic imaging with technetium-99m teboroxime during adenosine-induced coronary hyperemia with thallium-201 imaging. With the patient positioned on the imaging table, adenosine was infused at a rate of 140 micrograms/kg per min for 6 min. At 4 min, 20 to 25 mCi (740 to 925 MBq) of technetium-99m teboroxime was injected intravenously and imaging was started as soon as the infusion was completed with use of a 180 degrees anterior arc and 32 stops at 10 s/stop (total imaging time 7.8 min). Rest images were obtained 60 to 90 min later with use of a similar dose of technetium-99m teboroxime. Exercise tomographic thallium images were obtained within 2 weeks of the teboroxime studies. In the 20 patients studied, the teboroxime images were normal in 2 (50%) of 4 normal subjects and abnormal in 15 (94%) of 16 patients with coronary artery disease; 4 of the 15 had a fixed defect and 11 a reversible defect. There was agreement between teboroxime and thallium studies in 16 patients (80%), in 319 (80%) of 400 segments and in 50 (83%) of 60 vascular segments (p less than 0.05). In two normal subjects, an apparent fixed defect involving the inferior wall was seen on the teboroxime but not the thallium images and was thought to be due to an attenuation artifact secondary to extracardiac activity in the left lobe of the liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Human dopamine D5 receptor pseudogenes

Molecular cloning studies have now identified five structurally homologous genes encoding the biosynthesis of the human dopamine receptors, DRD1, DRD2, DRD3, DRD4, and DRD5. Two of these dopamine receptors (DRD1 and DRD5) are encoded by intronless genes. To ascertain whether there are other intronless genes that share identity with the gene (DRD5) encoding the DRD5 receptor, we used a cloning method based on the polymerase chain reaction (PCR). Human genomic DNA was amplified by PCR with oligodeoxyribonucleotides (oligos) based on the DRD5 nucleotide (nt) sequence. Amplification of nt sequences between these oligos allowed the isolation of two independent intronless genes that share identity with DRD5. The full-length clones have also been isolated by screening human genomic libraries. The deduced amino acid sequences for these genes, PG-1 and PG-2, share 91% and 92% identity to DRD5, respectively. However, each of the genes contains differences in the coding regions that would render these genes incapable of encoding functional receptors. Thus, the human genome contains at least two DRD5 pseudogenes, consistent with in situ human chromosomal hybridization analysis which reveals the presence of two pseudogenes.

Transcription of a human dopamine D5 pseudogene

We have previously reported that the human genome contains the two pseudogenes psi DRD5-1, and psi DRD5-2, and that each share 94% homology when compared with the functional gene DRD5. There is only 2% difference at the nucleotide level between the two pseudogenes. We questioned whether these pseudogenes were transcribed, since transcription of either of these pseudogenes could result in false interpretation of in-situ hybridization and Northern blot analysis, using the DRD5 as a probe. We now report that we have detected transcription of one of the pseudogenes, psi DRD5-1, in several human brain areas, and this mRNA transcript is capable of producing a protein of 154 amino acids. Furthermore we report that PCR amplification of DRD5 or the pseudogenes in human tissue can result in the formation of chimer artifacts due to the co-amplification of three very similar genes.

Evaluation of the role of conserved His and Met residues among lipoxygenases by site-directed mutagenesis of recombinant human 5-lipoxygenase

The 5-, 12-, and 15-lipoxygenases contain a highly conserved sequence of the form His-(X)4-His-(X)4-His-(X)17-His-(X)8-His which represents a potential binding site for non heme iron to the protein. The importance of selected amino acids within this His cluster for the activity of human 5-lipoxygenase was investigated by site-directed mutagenesis using bacteria and insect cells expression systems. After single mutation of each of the 5 His residues at positions 363, 368, 373, 391, and 400 by Ser, Cys, or Lys, measurable levels of 5-lipoxygenase activity could be recovered in Escherichia coli only for the Ser363 and Cys363 mutants, with most amino acid substitutions causing a decrease in the levels of expression of the soluble protein. In contrast, 25-80% of soluble 5-lipoxygenase activity was recovered after the replacement of several of the hydrophobic amino acids in this region: Tyr384 by Ser or Phe; Phe394 by Trp and Val375 by Ala. Met436 could be replaced by Leu with little effect on 5-lipoxygenase activity or turnover inactivation half-time. High levels of mutant 5-lipoxygenases containing a Ser residue instead of His at each of the five positions were also expressed in Spodoptera frugiperda (Sf9) cells infected with recombinant baculovirus. The specific activity (58-75% of control) and the reaction time course of the Ser363, Ser391, and Ser400 mutants were comparable with that of native 5-lipoxygenase whereas inactive proteins were obtained for the Ser368 and Ser373 mutants. These results show that His368 and His373 residues are important for 5-lipoxygenase activity and that the other conserved His363, His391, His400, and Met436 residues are not crucial for the catalytic cycle or for the mechanism of self-inactivation of 5-lipoxygenase.

Primary structure and biological activity of human brain-derived neurotrophic factor

Brain-derived neurotrophic factor (BDNF) is a 27-kDa basic protein of noncovalently linked 13.5-kD subunits related to nerve growth factor and is produced by the central nervous system (CNS). BDNF has been shown to promote the survival of neurons located in or directly connected with the CNS and is likely to function in adjusting the cell number within neuronal populations to the need of this projection field. Here we describe the primary structure of a human BDNF cDNA, the biological activities of pure recombinant human BDNF, and the tissue distribution of rat BDNF. BDNF mRNA can be found in some peripheral tissues as well as in the CNS, and recombinant human BDNF is a potent neurotrophic factor for primary peripheral sensory neurons.

Assessment of coronary artery disease using single-photon emission computed tomography with thallium-201 during adenosine-induced coronary hyperemia

Thallium-201 myocardial imaging during dipyridamole-induced coronary hyperemia has been an accepted method for diagnosing coronary artery disease (CAD) and risk stratification. Adenosine is a powerful short-acting coronary vasodilator. Initial results of thallium imaging during adenosine infusion have been encouraging. In 132 patients with CAD and in 16 patients with normal coronary angiograms, adenosine was given intravenously at a dose of 0.14 mg/kg/min for 6 minutes and thallium-201 was injected at 3 minutes. The thallium images using single-photon emission computed tomography were abnormal in 47 of the 54 patients (87%) with 1-vessel, in 34 of 37 patients (92%) with 2-vessel and in 40 of 41 patients (98%) with 3-vessel CAD. The sensitivity was 92% in the 132 patients with CAD (95% confidence intervals, 86 to 96%). In patients with normal coronary angiograms, 14 of 16 patients had normal thallium images (specificity, 88%; 95% confidence intervals, 59 to 100%). The results were very similar when subgroups of patients were analyzed: those without prior myocardial infarction, elderly patients and women. The nature of the perfusion defects (fixed or reversible) was assessed in relation to whether the 4-hour delayed images were obtained with or without the reinjection technique. In patients who underwent conventional delayed imaging, there were more fixed perfusion defects than in patients with reinjection delayed imaging (16 vs 0%, p less than 0.0001). The adverse effects were mild, transient and well tolerated. Thus, adenosine thallium tomographic imaging provides a high degree of accuracy in the diagnosis of CAD. The use of the reinjection technique enhances the ability to detect reversible defects.

Oxygen free radical injury of IEC-18 small intestinal epithelial cell monolayers

Oxygen radicals can cause endothelial and epithelial permeability changes and mucosal injury of the small intestine. There is no clear consensus concerning the relative injurious potential of individual oxygen radicals. In this study, the small intestinal cell line IEC-18 was used as an in vitro model to study the relative injurious effects of reactive oxygen metabolites. By introducing different combinations of oxygen metabolite-producing enzymes, xanthine oxidase, superoxide dismutase, and catalase, and an iron chelator, deferoxamine, to the fully confluent monolayers and to proliferating IEC-18 cells, the differential injurious effects of the oxygen metabolites O2-, H2O2, and OH. could be evaluated. The extent of cellular injury was assessed using [3H]thymidine uptake, 51Cr release, and morphological evaluations. Our results suggest that OH. produced as a by-product of O2- and H2O2 via the Haber-Weiss reaction was the most injurious oxygen species involved in cellular injury of IEC-18 monolayers induced by xanthine oxidase. O2- produced by xanthine oxidase appeared to be only minimally injurious, and H2O2 produced by xanthine oxidase and as a result of conversion of O2- by superoxide dismutase was moderately injurious. Superoxide dismutase and deferoxamine at appropriate concentrations were protective against xanthine/xanthine oxidase-induced monolayer injury. H2O2 added directly or produced indirectly by glucose oxidase was very injurious to the intestinal monolayers, and this injury was mitigated by catalase.

Effects of acute exposure to formaldehyde on surface morphology of nasal epithelia in rats

This study investigated the distribution of epithelial cells over the turbinates in the rat nasal cavity and their injury following exposure to formaldehyde. Rats were exposed to either purified air or 10 ppm formaldehyde for a period of 4 h. The noses removed from these rats were decalcified, sectioned midsagittally along the septum to expose the internal turbinates, and processed for examination by scanning electron microscopy. The distribution of the various cell types present was documented in the control rats. Observations obtained from the formaldehyde-exposed rats were compared to those in rats exposed to purified air. Changes were seen in the various regions of the turbinates in the form of ciliary destruction and cell separation (especially in the naso- and moxilloturbinates), cellular swelling (throughout the turbinates), mucus release by the goblet cells (in the nasoturbinate), and in some cases pores on the cell surface or between adjacent cells (evident in the middle meatus). The data from this study indicate that the degree of deleterious effects of formaldehyde on the nasal epithelia of rats is dependent upon cell type and location. Histological studies supported the scanning electron microscopic observations by demonstrating increased goblet cell volume, cell sloughing, and damaged cilia.

Pharmacokinetics and pharmacodynamics of nifedipine in children with bronchopulmonary dysplasia and pulmonary hypertension

The pharmacokinetics and associated pharmacodynamics of nifedipine were studied in nine children aged 5 to 68 mo with bronchopulmonary dysplasia and pulmonary artery hypertension after a single oral dose of 1.44 mumol/kg (0.5 mg/kg). In the cardiac catheterization laboratory, hemodynamic measurements were made in duplicate just before the nifedipine dose and at 5 min and 0.5 and 1.0 h after the dose. The plasma nifedipine concentration was measured by HPLC at each of the above times and at 2.5, 4.0, 6.0, and 8.0 h after the dose. The mean (+/- SD) maximum plasma concentration and the time to maximum plasma concentration were 243.4 +/- 194.5 nmol/L and 1.0 +/- 0.8 h, respectively. The mean area under the plasma concentration-time curve was 761 +/- 509 nmol.h/L. The mean elimination rate constant and t1/2 were 0.456 +/- 0.194 h-1 and 1.8 +/- 0.8 h, respectively. Nifedipine caused a significant (p less than or equal to 0.05) reduction in the mean pulmonary artery pressure by 5 min and in the mean pulmonary vascular resistance index and mean aortic pressure by 30 min, and these reductions remained significant through the 1-h measurement interval. The magnitude of acute hemodynamic response correlated closely with the plasma nifedipine concentrations. No significant change occurred in the mean arterial oxygen saturation or cardiac index during the study period. The percentage changes from baseline in the mean pulmonary artery pressure and mean pulmonary vascular resistance index were approximately double the percentage change in the mean aortic pressure, suggesting that nifedipine had some degree of selective impact on the pulmonary vascular bed.(ABSTRACT TRUNCATED AT 250 WORDS)

Curdlan sulfate and HIV-1. I. In vitro inhibitory effects of curdlan sulfate on HIV-1 infection

Action mechanisms of a newly synthesized polysaccharide, curdlan sulfate (CRDS), on human immunodeficiency virus type 1 (HIV-1) infection were investigated in vitro using syncytium formation microassay and p24 antigen capture enzyme-linked immunosorbent assay. These assays measured the titer of infectious virions and the amounts of HIV-1 core antigen p24 in soluble, intraviral, and intracellular forms. CRDS treatments were performed for 1 h at 37 degrees C. H9 cells pretreated with 0.1 to 100.0 micrograms/ml of CRDS appreciably inhibited HIV-1 infection. CRDS-treated HIV-1 virions were less able to infect H9 cells than untreated virions. The simultaneous treatment of H9 cells and HIV-1 virions with CRDS induced a significant inhibition of HIV-1 infection, resulting in the temporary disappearance of virions at the highest dose of CRDS. In contrast, CRDS treatment of newly HIV-1-infected H9 cells caused a significant decrease in the titer of infectious HIV-1 and the p24 amounts of all three forms, but no absolute elimination. Taken together, these results indicate that CRDS may block the binding of the HIV-1 envelope to the H9 cell surface, with emphasis on the high affinity of CRDS to the HIV-1 envelope.

Myocardial imaging with Tc-99m teboroxime: technique and initial results

This study examined the results of Tc-99m teboroxime imaging in 22 patients aged 59 +/- 9 years and compared the results with those of thallium-201. The exercise and rest teboroxime studies were obtained within 3 hours of each other using a dose of 15 mCi/study. Because of the very short wash-out half-life of teboroxime, imaging was begun within 1 to 2 minutes after injection. Both SPECT and planar images were obtained; the SPECT protocol was modified by changing the number of frames, the time per frame, or the filters used for reconstruction of images. The planar images were obtained in the supine or upright position. Shorter acquisition time for SPECT (10 sec/frame) and the use of a Butterworth filter with a frequency cutoff of 0.3 cycle/cm and a power of 10 yielded best image quality. There was a close agreement with thallium results in identifying an abnormal or normal perfusion pattern in 89% of vascular territories. The scans were abnormal by both techniques in 12 patients, normal in nine patients, and discordant in only one patient. Thus Tc-99m teboroxime myocardial imaging is feasible at rest and during exercise using either SPECT or planar imaging. Shorter acquisition time and appropriate filtering for SPECT imaging and the upright position in planar imaging improve image quality and are convenient for the patient.

Molecular cloning of a human basic fibroblast growth factor receptor cDNA and expression of a biologically active extracellular domain in a baculovirus system

A cDNA clone encoding a human fibroblast growth factor (FGF) receptor was isolated from a hepatoma cell line cDNA library. The cDNA encodes a three immunoglobulinlike-domain FGF receptor that is similar to a human placental FGF receptor cDNA but lacks two amino acids. The variation observed at these two amino acids, also seen in the two immunoglobulinlike-domain FGF-receptors, can be explained by an alternate splicing mechanism. We have used a baculovirus expression system to produce high levels of a soluble, extracellular domain form of the FGF receptor (EC-FGF receptor). Spodoptera frugiperda (Sf9) insect cells infected with recombinant EC-FGF receptor viruses synthesized and secreted an EC-FGF receptor of apparent Mr = 58,000. The EC-FGF receptor purified from conditioned media of infected Sf9 cells by lentil lectin affinity chromatography was shown to bind basic FGF with high affinity (Kd = 1-5 nM), to inhibit the binding of radioiodinated basic FGF to its high affinity receptor and to inhibit endothelial cell proliferation. Furthermore, binding of basic FGF to the EC-FGF receptor was shown to be significantly enhanced by heparin. The availability of biologically active FGF receptors will allow an analysis of their interaction with members of the FGF family of proteins and viruses of the herpes family that have been shown to use the FGF receptor system for cell entry.

Single photon emission computed tomography with thallium-201 during adenosine-induced coronary hyperemia: correlation with coronary arteriography, exercise thallium imaging and two-dimensional echocardiography

The feasibility, safety and diagnostic accuracy of single photon emission computed tomography (SPECT) with thallium-201 imaging during adenosine-induced coronary hyperemia were evaluated in 53 patients with and 7 without coronary artery disease proved by coronary angiography. Adenosine was infused intravenously at a dose of 0.14 mg/kg body weight per min for 6 min and thallium was injected at 3 min. Adenosine caused an increase in heart rate (68 +/- 12 at baseline versus 87 +/- 18 beats/min at peak effect, p less than 0.0001) but no change in blood pressure. The sensitivity and specificity were 92% (95% confidence intervals 81% to 98%) and 100% (95% confidence intervals 59% to 100%), respectively; 20 (61%) of 33 patients with multivessel coronary artery disease were also correctly identified. In 30 patients, the predictive accuracy of adenosine thallium imaging was slightly higher than that of exercise SPECT thallium imaging (90% versus 80%, p = NS) (95% confidence intervals 72% to 97% and 61% to 92%, respectively). In 25 patients, two-dimensional echocardiography during adenosine infusion disclosed a new wall motion abnormality in 2 (10%) of 20 patients with coronary artery disease; 80% of these patients had reversible thallium defects (p less than 0.001). Side effects were mild and transient; aminophylline was used in only three patients. Thus, adenosine SPECT thallium imaging provides a high degree of accuracy in the diagnosis of coronary artery disease. The results are comparable with those of exercise SPECT thallium imaging. Most reversible defects in the adenosine study are not associated with any transient wall motion abnormality.

Left ventricular dilatation and pulmonary thallium uptake after single-photon emission computer tomography using thallium-201 during adenosine-induced coronary hyperemia

This study examined the implications of left ventricular (LV) dilatation and increased pulmonary thallium uptake during adenosine-induced coronary hyperemia. The lung-to-heart thallium ratio in the initial images was significantly higher in patients with coronary artery disease (CAD) than normal subjects; 0.48 +/- 0.16 in 3-vessel disease (n = 16), 0.43 +/- 0.10 in 2-vessel disease (n = 20), 0.43 +/- 0.08 in 1-vessel disease (n = 16) and 0.36 +/- 0.05 in normal subjects (n = 7) (p less than 0.001, 0.09 and 0.06, respectively). There was a significant correlation between the severity and the extent of the perfusion abnormality (determined from the polar maps) and the lung-to-heart thallium ratio (r = 0.51 and 0.52, respectively, p less than 0.0002). There was also a significant correlation between lung thallium washout and lung-to-heart thallium ratio (r = 0.42, p = 0.0009) and peak heart rate (r = -0.49, p less than 0.0001). The LV dilatation was mostly due to an increase in cavity dimension (30% increase) and to a lesser extent (6% increase) due to increase in LV size. (The cavity dimensions were measured from the short-axis slices at the midventricular level in the initial and delayed images). The dilation was seen in patients with CAD but not in the normal subjects. These changes correlated with the extent and severity of the thallium perfusion abnormality. Thus, adenosine-induced coronary hyperemia may cause LV dilation and increased lung thallium uptake on the basis of subendocardial ischemia.

[Place of implantology in the treatment plan: apropos of some clinical situations]

The advent of osseointegrated implants has considerably influenced the treatment of the edentulism. The Brånemark's protocol allows a high enough degree of predictability for a wide variety of clinical applications. A selection of the most typical indications attempts to focus on the benefit of implant supported prosthesis, regarding the conventional prosthetic treatment. The relative indications concern single-tooth replacement and Kennedy class III situations where classical tooth supported bridge is not easily feasible. The resort to osseointegration treatment enhances the possibilities of prosthetic rehabilitation in unfavorable conditions. The greater part of the indications is represented by Kennedy class I and class II situations. Clinical examples selected show the different combinations related to the fixtures position in the maxilla where bone availability is reduced. When just one fixture can be installed, connection with adjacent tooth must be carefully indicated. With two fixtures, a bridge must be designed with a posterior cantilever. But the opposite dentition can also dictate a fixture installation in the posterior region for a good occlusal stabilization: a specific modality of fixture installation in the pterygoid region has provided a seductive alternative. The last part concerns the prosthetic rehabilitation of advanced cases involving evolutive periodontal disease. The current trends determine a flexible approach with strategic extractions and progressive fixtures installation during stabilized periods of the disease activity. This management of the treatment planning reduces the psychogenic stress related to the complete edentulism and allows a easier transition from partial implant supported-prosthesis to fully bone anchored-prosthesis.

Medication compliance, antidepressant blood levels, and side effects in Southeast Asian patients

A study of medication compliance, side effects, and clinical change with the use of antidepressants in 32 Southeast Asian refugee patients seen at an urban mental health center is reported. Patients met criteria for either major depressive episode, posttraumatic stress disorder, or both. Only five of the 32 patients who stated that they were taking their medications regularly had antidepressant blood levels in the therapeutic range. Another 10 patients had subtherapeutic levels and the remaining 17 had undetectable blood levels. Patients with therapeutic blood levels had fewer side effects (p = 0.049) than patients with undetectable blood levels. Blood levels tended (p = 0.070) to be correlated with clinical improvement. The authors discuss cultural attitudes of Southeast Asian refugee patients toward medication use and side effects that appear to influence medication compliance.