Characteristics of salivary diffuse infiltrative lymphocytosis syndrome in West Africa

OBJECTIVE

To determine the prevalence of diffuse infiltrative lymphocytosis syndrome (DILS) in the minor salivary glands of 30 African Cameroonian adults with the acquired immunodeficiency syndrome (AIDS).

DESIGN

Salivary gland tissue was analyzed using a modified classification system that was developed to aid the diagnosis of Sjögren syndrome. The advantages and disadvantages of this approach are discussed.

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded, hematoxylin-eosin-stained biopsy sections were prepared for 30 patients with AIDS, 26 healthy individuals who declined human immunodeficiency virus (HIV) testing, and 4 seronegative healthy controls. Tissues were immunostained for CD4/CD8+ lymphocytes and cytomegalovirus (CMV), and transmission electron microscopy was performed to locate viral particles. Patients were tested for HIV-1 and HIV-2 by the HIV/Chek System 3 or CAMSTIX-HIV-1 and HIV-2 assay.

RESULTS

Severe salivary ductal atypia (96%) was the feature most strongly associated with AIDS, and the lymphocytic focus score was the second histologic feature most strongly correlated with AIDS. Forty-eight percent of patients with HIV-1 infection had more than 1 lymphocytic focus in a minor salivary gland. These lymphocytes were primarily CD8+. We report, to the best of our knowledge, the first case of multinucleated salivary duct epithelial cells in minor salivary glands also containing enveloped virus particles. All cases were negative for CMV.

CONCLUSIONS

The prevalence of DILS in West Africans with AIDS appears higher than the prevalence reported in whites from the United States and Europe and in blacks from the United States, a group that has been reported to have a greater incidence of DILS than whites. This discrepancy may be related to differences in patient selection criteria. The determination of lymphocytic focus score, as used in the diagnosis of Sjögren syndrome, with the adjunct of ductal atypia is useful for assessing DILS. The impact of patient selection, drug therapy, and parasites on salivary gland pathology is discussed.

Effect of budesonide and salbutamol on surfactant properties

The objective of this study was to evaluate the in vitro effect of budesonide and salbutamol on the surfactant biophysical properties. The surface-tension properties of two bovine lipid extracts [bovine lipid extract surfactant (BLES) and Survanta] and a rat lung lavage natural surfactant were evaluated in vitro by the captive bubble surfactometer. Measurements were obtained before and after the addition of a low and high concentration of budesonide and salbutamol. Whereas salbutamol had no significant effect, budesonide markedly reduced the surface-tension-lowering properties of all surfactant preparations. Surfactant adsorption (decrease in surface tension vs. time) was significantly reduced (P < 0.01) at a high budesonide concentration with BLES, both concentrations with Survanta, and a low concentration with natural surfactant. At both concentrations, budesonide reduced (P < 0.01) Survanta film stability (minimal surface vs. time at minimum bubble volume), whereas no changes were seen with BLES. The minimal surface tension obtained for all surfactant preparations was significantly higher (P < 0.01), and the percentage of film area compression required to reach minimum surface tension was significantly lower after the addition of budesonide. In conclusion, budesonide, at concentrations used therapeutically, adversely affects the surface-tension-lowering properties of surfactant. We speculate that it may have the same adverse effect on the human surfactant.

Expression of phosphodiesterase 4D (PDE4D) is regulated by both the cyclic AMP-dependent protein kinase and mitogen-activated protein kinase signaling pathways. A potential mechanism allowing for the coordinated regulation of PDE4D activity and expression in cells

Multiple families of cyclic nucleotide phosphodiesterases (PDE) have been described, and the regulated expression of these genes in cells is complex. Although cAMP is known to control the expression of certain PDE in cells, presumably reflecting a system of feedback on cAMP signaling, relatively little is known about the influence of non-cAMP signaling systems on PDE expression. In this study, we describe a novel mechanism by which activators of the protein kinase C (PKC)-Raf-MEK-ERK cascade regulate phosphodiesterase 4D (PDE4D) expression in vascular smooth muscle cells (VSMC) and assess the functional consequences of this effect. Whereas a prolonged elevation of cAMP in VSMC resulted in a protein kinase A (PKA)-dependent induction of expression of two PDE4D variants (PDE4D1 and PDE4D2), simultaneous activation of both the cAMP-PKA and PKC-Raf-MEK-ERK signaling cascades blunted this cAMP-mediated increase in PDE4D expression. By using biochemical, molecular biological, and pharmacological approaches, we demonstrate that this PDE4D-selective effect of activators of the PKC-Raf-MEK-ERK cascade was mediated through a mechanism involving altered PDE4D mRNA stability and markedly attenuated the cAMP-mediated desensitization that results from prolonged activation of the cAMP signaling system in cells. The data are presented in the context of activators of the PKC-Raf-MEK-ERK cascade having both short and long term effects on PDE4D activity and expression in cells that may influence cAMP signaling.

Dual expression and differential regulation of phosphodiesterase 3A and phosphodiesterase 3B in human vascular smooth muscle: implications for phosphodiesterase 3 inhibition in human cardiovascular tissues

Cyclic nucleotide phosphodiesterases (PDEs) are a superfamily of enzymes whose physiological role is the attenuation of the signaling mediated by the ubiquitous second messengers cAMP and cGMP. Given the myriad of physiological processes regulated by cAMP and cGMP, PDEs have long been studied as potential therapeutic targets. Although phosphodiesterase 3 (PDE3) activity is abundant in human cardiovascular tissues, and acute PDE3 inhibition, with agents such as milrinone, was beneficial in heart failure patients, prolonged treatments were associated with time-dependent reductions in hemodynamic effects and increased mortality. The molecular basis of this time-dependent reduction in efficacy has not been elucidated. In this context, we used a combination of approaches to determine PDE3 expression in human cardiovascular tissues and to elucidate the effects of prolonged elevations of cellular cAMP, as would occur with PDE3 inhibition, on this activity. Although our data confirms the expression of PDE3A in human blood vessel smooth muscle cells (HASMCs), we identify a previously unrecognized role for PDE3B in cAMP hydrolysis in human cardiovascular tissues. Specifically, although both PDE3A and PDE3B were expressed in HASMCs, their subcellular expression pattern and regulated expression by cAMP were distinct, with only expression of PDE3B being subject to cAMP-regulated expression. Thus, a paradigm emerges that allows for dual expression, with distinctive regulation, of both PDE3A and PDE3B proteins in cardiovascular tissues that may have profound significance for the rational design of molecules regulating this PDE activity.

A system for monitoring the response of uniaxial strain on cell seeded collagen gels

The success of cell seeded constructs for the repair of collagenous tissues may be improved by the use of mechanical stimulation in vitro. A mechanical loading apparatus, termed the cell straining system, was developed according to a set of design criteria, to enable cell seeded constructs to be cyclically loaded in tension. A suitable cell seeded collagen gel model system was used to characterise the apparatus. These gels were subjected to a cyclic strain of 10% superimposed on two separate tare loads of 2 and 10 mN, while being maintained in cell culture conditions. The computer controlled apparatus was shown to be capable of monitoring the individual loads on six specimens simultaneously, to an accuracy of 0.02 mN. Results indicated a wide variability between individual specimens. Following cyclic loading, the cell seeded collagen gels exhibited an increase in structural stiffness compared with the unloaded controls. This novel and versatile apparatus will provide a means of enhancing structural and mechanical integrity of tissue engineered repair systems.

Adjuvant radiation trials for high-risk breast cancer patients: adequacy of lymphadenectomy

BACKGROUND

The recently published, widely publicized adjuvant radiation trials from Denmark and Canada concluded that the addition of postoperative radiotherapy (XRT) to modified radical mastectomy (MRM) and adjuvant chemotherapy reduces locoregional recurrences and prolongs survival in high-risk premenopausal patients with breast cancer. Our thesis is that adequate lymphadenectomies were not performed in either study. Consequently, the conclusion to these studies is not applicable to those patients who have undergone adequate surgery.

METHODS

To better assess adequate lymph node yield from an MRM, a retrospective review was performed on 215 consecutive patients treated surgically for invasive breast cancer. Data from this review were compared with the surgical data from the above-mentioned radiotherapy trials.

RESULTS

In a group of 131 patients who had MRM, the average number of nodes removed was 26 (median, 25), and 75.5% of the specimens had 20 or more lymph nodes. In 73 patients who underwent segmental mastectomy with axillary lymph node dissection, both the average and the median number of lymph nodes removed were 24, and 68.9% had 20 or more nodes. These data compare to the Danish radiation trial in which a median of 7 lymph nodes were removed (with 76% of the patients having 9 or fewer lymph nodes in the specimen) and to the Canadian radiation trial in which a median of 11 lymph nodes were removed. In addition, in our breast cancer patients with positive nodes (84 of 204; 41.2%), 45.2.% (38 of 84) had more than three positive nodes compared with 29.8% in the Danish study and 35% in the Canadian study.

CONCLUSIONS

Our surgical data are sufficiently different from those of the Danish and Canadian studies to indicate that, in those studies, incomplete lymph node dissections were performed and that residual disease was left behind in the axilla in some or all of the patients. The addition of XRT in the setting of residual axillary disease may compensate for an inadequate operation and yield an acceptable oncological result; however, these studies did not provide an adequate comparison with a well-performed MRM without XRT. In the absence of documented benefit, XRT should not be routinely added if a complete lymph node dissection has been performed.

The role of intrahepatic lymphocytes in mediating protective immunity induced by attenuated Plasmodium berghei sporozoites

Exposure to irradiated Plasmodium sporozoites (gamma-spz) results in protection against malaria. Like infectious spz, gamma-spz colonize hepatocytes to undergo maturation. Disruption of liver stage development prevents the generation of protection, which appears, therefore, to depend on liver stage antigens. Although some mechanisms of protection have been identified, they do not include a role for intrahepatic mononuclear cells (IHMC). We demonstrated that P. berghei gamma-spz-immune murine IHMC adoptively transfer protection to naive recipients. Characterization of intrahepatic CD4+ T cells revealed an immediate, albeit transient, response to gamma-spz, while the response of CD8+ T cells is delayed until acquisition of protection. It is presumed that activated CD8+ T cells home to the liver to die; gamma-spz-induced CD8+CD45RB(lo)CD44(hi) T cells, however, persist in the liver, but not the spleen, during protracted protection. The association between CD8+CD45RB(lo)CD44(hi) T cells and protection has been verified using MHC class I and CD1 knockout mice and mice with disrupted liver stage parasites. Based on kinetic studies, we propose that interferon-gamma, presumably released by intrahepatic effector CD8+ T cells, mediates protection; the persistence of CD8+ T cells is, in turn, linked to Plasmodium antigen depots and cytokines released by CD4+ T cells and/or NK T cells.

Alterations in pulmonary surfactant after rapid arousal from torpor in the marsupial Sminthopsis crassicaudata

Torpor in the dunnart, Sminthopsis crassicaudata, alters surfactant lipid composition and surface activity. Here we investigated changes in surfactant composition and surface activity over 1 h after rapid arousal from torpor (15-30 degrees C at 1 degrees C/min). We measured total phospholipid (PL), disaturated PL (DSP), and cholesterol (Chol) content of surfactant lavage and surface activity (measured at both 15 and 37 degrees C in the captive bubble surfactometer). Immediately after arousal, Chol decreased (from 4.1 +/- 0.05 to 2.8 +/- 0.3 mg/g dry lung) and reached warm-active levels by 60 min after arousal. The Chol/DSP and Chol/PL ratios both decreased to warm-active levels 5 min after arousal because PL, DSP, and the DSP/PL ratio remained elevated over the 60 min after arousal. Minimal surface tension and film compressibility at 17 mN/m at 37 degrees C both decreased 5 min after arousal, correlating with rapid changes in surfactant Chol. Therefore, changes in lipids matched changes in surface activity during the postarousal period.

Effect of leptin deficiency on metabolic rate in ob/ob mice

Reduced metabolic rate may contribute to weight gain in leptin-deficient (ob/ob) mice; however, available studies have been criticized for referencing O2 consumption (VO2) to estimated rather than true lean body mass. To evaluate whether leptin deficiency reduces energy expenditure, four separate experiments were performed: 1) NMR spectroscopy was used to measure fat and nonfat mass, permitting VO2 to be referenced to true nonfat mass; 2) dietary manipulation was used in an attempt to eliminate differences in body weight and composition between ob/ob and C57BL/6J mice; 3) short-term effects of exogenous leptin (0.3 mg. kg-1. day-1) on VO2 were examined; and 4) body weight and composition were compared in leptin-repleted and pair-fed ob/ob animals. ob/ob animals had greater mass, less lean body mass, and a 10% higher metabolic rate when VO2 was referenced to lean mass. Dietary manipulation achieved identical body weight in ob/ob and C57BL/6J animals; however, despite weight gain in C57BL/6J animals, percent fat mass remained higher in ob/ob animals (55 vs. 30%). Exogenous leptin increased VO2 in ob/ob but not control animals. Weight loss in leptin-repleted ob/ob mice was greater than in pair-fed animals (45 vs. 17%). We conclude, on the basis of the observed increase in VO2 and accelerated weight loss seen with leptin repletion, that leptin deficiency causes a reduction in metabolic rate in ob/ob mice. In contrast, these physiological studies suggest that comparison of VO2 in obese and lean animals does not produce useful information on the contribution of leptin to metabolism.

Supermirror hard-x-ray telescope

The practical use of a grazing x-ray telescope is demonstrated for hard-x-ray imaging as hard as 40 keV by means of a depth-graded d-spacing multilayer, a so-called supermirror. Platinum-carbon multilayers of 26 layer pairs in three blocks with a different periodic length d of 3-5 nm were designed to enhance the reflectivity in the energy range from 24 to 36 keV at a grazing angle of 0.3 deg. The multilayers were deposited on thin-replica-foil mirrors by a magnetron dc sputtering system. The reflectivity was measured to be 25%-30% in this energy range; 20 mirror shells thus deposited were assembled into the tightly nested grazing-incidence telescope. The focused hard-x-ray image was observed with a newly developed position-sensitive CdZnTe solid-state detector. The angular resolution of this telescope was found to be 2.4 arc min in the half-power diameter.

Central line exit sites: which dressing?

Recent developments in dressings for intravenous access sites include a transparent dressing which does not retain moisture. This article describes a randomised controlled trial to compare the new dressing with a standard dressing. There was no difference in sepsis rates between the two groups, and both methods had advantages and disadvantages. The authors suggest that cost may be a factor in choice of dressing.

Endotoxin-induced alteration in the expression of leptin and beta3-adrenergic receptor in adipose tissue

Cytokines, such as tumor necrosis factor (TNF) and interleukin-6, may contribute to the anorexia and cachexia of infection, cancer, and AIDS. The present study tests the hypothesis that endotoxin alters the expression of two key fat cell proteins, leptin and beta3-adrenergic receptor (beta3-AR), through a mechanism involving TNF-alpha. Increasing doses of Escherichia coli endotoxin (lipopolysaccharide, LPS) resulted in dose-dependent elevations of plasma leptin (maximal response approximately 7-fold, half-maximal effective dose of approximately 16 microg/100 g body wt) and white fat leptin mRNA in C3/HeOUJ mice. LPS also produced a large decrease in adipose tissue beta3-AR mRNA and a parallel reduction in beta-agonist-induced activation of adenylyl cyclase. Changes in plasma leptin and beta3-AR mRNA were preceded by an approximately threefold increase in white fat TNF mRNA. TNF administration resulted in changes similar to those seen with LPS. We conclude that endotoxemia results in an induction of leptin mRNA and a decrease in beta3-AR mRNA in adipose tissue, an effect that may be mediated by alterations in TNF-alpha.

Synergistic inhibition of vascular smooth muscle cell migration by phosphodiesterase 3 and phosphodiesterase 4 inhibitors

Cyclic nucleotide phosphodiesterases (PDEs) hydrolyze cAMP or cGMP and terminate their signaling. Two important families of PDEs that regulate cAMP signaling in cardiovascular tissues are the cGMP-inhibited PDEs (PDE3) and the cAMP-specific PDEs (PDE4). In this study, we have used a combination of an in vitro motility assay and a sensitive method for the measurement of cAMP in order to determine the relative roles of PDE3 and of PDE4 in the regulation of cAMP-mediated inhibition of VSMC migration. Our data demonstrate that forskolin, an activator of adenylyl cyclases, causes concentration-dependent inhibition of platelet-derived growth factor-induced VSMC migration. Incubation of cultured VSMCs with a PDE4-selective inhibitor, Ro 20-1724, markedly potentiated both the antimigratory effect and the increase in cAMP caused by forskolin. Cilostamide, a PDE3-selective compound, did not affect either the antimigratory activity of forskolin or its ability to increase cAMP. Cilostamide and Ro 20-1724 interacted synergistically to potentiate the inhibition of VSMC migration by forskolin and caused a supra-additive increase in cAMP. These data are consistent with an important role for both PDE3 and PDE4 in the regulation of cAMP-mediated inhibition of VSMC migration.

Alterations in the surface properties of lung surfactant in the torpid marsupial Sminthopsis crassicaudata

Torpor changes the composition of pulmonary surfactant (PS) in the dunnart Sminthopsis crassicaudata [C. Langman, S. Orgeig, and C. B. Daniels. Am. J. Physiol. 271 (Regulatory Integrative Comp. Physiol, 40): R437-R445, 1996]. Here we investigated the surface activity of PS in vitro. Five micrograms of phospholipid per centimeter squared surface area of whole lavage (from mice or from warm-active, 4-, or 8-h torpid dunnarts) were applied dropwise onto the sub-phase of a Wilhelmy-Langmuir balance at 20 degrees C and stabilized for 20 min. After 4 h of torpor, the adsorption rate increased, and equilibrium surface tension (STeq), minimal surface tension (STmin), and the %area compression required to achieve STmin decreased, compared with the warm-active group. After 8 h of torpor, STmin decreased [from 5.2 +/- 0.3 to 4.1 +/- 0.3 (SE) mN/m]; %area compression required to achieve STmin decreased (from 43.4 +/- 1.0 to 27.4 +/- 0.8); the rate of adsorption decreased; and STeq increased (from 26.3 +/- 0.5 to 38.6 +/- 1.3 mN/m). ST-area isotherms of warm-active dunnarts and mice at 20 degrees C had a shoulder on compression and a plateau on expansion. These disappeared on the isotherms of torpid dunnarts. Samples of whole lavage (from warm-active and 8-h torpor groups) containing 100 micrograms phospholipid/ml were studied by using a captive-bubble surfactometer at 37 degrees C. After 8 h of torpor, STmin increased (from 6.4 +/- 0.3 to 9.1 +/- 0.3 mN/m) and %area compression decreased in the 2nd (from 88.6 +/- 1.7 to 82.1 +/- 2.0) and 3rd (from 89.1 +/- 0.8 to 84.9 +/- 1.8) compression-expansion cycles, compared with warm-active dunnarts. ST-area isotherms of warm-active dunnarts at 37 degrees C did not have a shoulder on compression. This shoulder appeared on the isotherms of torpid dunnarts. In conclusion, there is a strong correlation between in vitro changes in surface activity and in vivo changes in lipid composition of PS during torpor, although static lung compliance remained unchanged (see Langman et al. cited above). Surfactant from torpid animals is more active at 20 degrees C and less active at 37 degrees C than that of warm-active animals, which may represent a respiratory adaptation to low body temperatures of torpid dunnarts.

Analysis of the tyrosine phosphorylation and calcium fluxing of human CD6 isoforms with different cytoplasmatic domains

CD6 is a cell surface glycoprotein that functions both as a co-stimulatory and adhesion receptor on T cells. Recently we have described CD6 isoforms (CD6a, b, c, d, e) that arise via alternative splicing of exons encoding the cytoplasmic region of the molecule. CD6 becomes phosphorylated on tyrosine (Tyr) residues following stimulation through the T cell receptor (TCR) complex. Since the phosphorylation of Tyr residues renders some cell surface receptors competent for interactions with proteins of intracellular signaling pathways, we wanted to determine which region(s) and residues in the cytoplasmic domain of CD6 were important for phosphorylation on Tyr residues. We engineered and stably expressed chimeric receptors that consisted of the extracellular region of mouse CD6 and the cytoplasmic regions of either naturally occurring isoforms of human CD6, truncated proteins, or point mutants. We were able to demonstrate that of the nine Tyr residues in the cytoplasmic domain of the largest isoform CD6a, the two C-terminal Tyr residues (Tyr 629/662) are critical for the phosphorylation of CD6 following TCR cross-linking. Isoform CD6e, which is missing a region that contains two proline-rich motifs, is not phosphorylated. We further analyzed the ability of the different CD6 isoforms and truncated receptors to mobilize intracellular calcium after CD6/TCR co-ligation. All CD6 isoforms, including CD6e, as well as the truncation mutant delta 555, which is missing approximately the C-terminal half of the cytoplasmic domain, are able to increase Ca2+ influx. Taken together, these results suggest that the region of CD6 which is critical for Ca2+ mobilization is located N-terminal from amino acid 555 and is therefore different from the region located at the C terminus of CD6, which is necessary for tyrosine phosphorylation.

Cyclic AMP-mediated regulation of vascular smooth muscle cell cyclic AMP phosphodiesterase activity

1. Rat cultured aortic vascular smooth muscle cells (VSMC) express both cyclic GMP-inhibited cyclic AMP phosphodiesterase (PDE3) and Ro 20-1724-inhibited cyclic AMP phosphodiesterase (PDE4) activities. By utilizing either cilostamide, a PDE3-selective inhibitor, or Ro 20-1724, a PDE4-selective inhibitor, PDE3 and PDE4 activities were shown to account for 15% and 55% of total VSMC cyclic AMP phosphodiesterase (PDE) activity. 2. Treatment of VSMC with either forskolin or 8-bromo-cyclic AMP caused significant concentration- and time-dependent increases in total cellular cyclic AMP PDE activity. Using cilostamide or Ro 20-1724, we demonstrated that both PDE3 and PDE4 activities were increased following forskolin or 8-bromo-cyclic AMP treatment, with a relatively larger effect observed on PDE3 activity. The increase in cyclic AMP PDE activity induced by forskolin or 8-bromo-cyclic AMP was inhibited by actinomycin D or cycloheximide, demonstrating that new mRNA synthesis and protein synthesis were required. An analogue of forskolin which does not activate adenylyl cyclase (1,9-dideoxyforskolin) or an analogue of cyclic GMP (8-bromo-cyclic GMP) did not affect total cyclic AMP PDE activity. 3. Incubation of VSMC with 8-bromo-cyclic AMP for 16 h caused a marked rightward shift in the concentration-response curves for both isoprenaline- and forskolin-mediated activation of adenylyl cyclase. A role for up-regulated cyclic AMP PDE activity in this reduced potency is supported by our observation that cyclic AMP PDE inhibitors (IBMX, cilostamide or Ro 20-1724) partially normalized the effects of isoprenaline or forskolin in treated cells to those in untreated cells. 4. We conclude that VSMC cyclic AMP PDE activity is increased following long-term elevation of cyclic AMP and that increases in PDE3 and PDE4 activities account for more than 70% of this effect. Furthermore, we conclude that increases in cyclic AMP PDE activity contribute to the reduced potency of isoprenaline or forskolin in treated VSMC. These results have implications for long-term use of cyclic AMP PDE inhibitors as therapeutic agents.

Characterization of mouse ALCAM (CD166): the CD6-binding domain is conserved in different homologs and mediates cross-species binding

Activated leukocyte cell adhesion molecule (ALCAM; CD166) is a member of the immunoglobulin gene superfamily (IgSF) which is expressed by activated leukocytes and thymic epithelial cells and is a ligand for the lymphocyte antigen CD6. Herein, we report on the isolation and characterization of cDNA clones encoding mouse ALCAM (mALCAM). Comparison of the predicted amino acid sequence of mALCAM and human ALCAM (hALCAM) showed an overall identity of 93%. Binding studies with truncated forms of the extracellular region of mALCAM showed that the CD6 binding site is located in the N-terminal Ig-like domain and that mALCAM is capable of binding both human and mouse CD6. Mutagenesis studies on hALCAM suggested that residues critical for CD6 binding map to the predicted A'GFCC'C" beta-sheet of ALCAM's N-terminal binding domain. Residue differences in the N-terminal domains of mALCAM and hALCAM were analyzed with the aid of a molecular model of ALCAM. All residues critical for CD6 binding are conserved in both mALCAM and hALCAM, whereas residue differences map to the predicted BED face which is opposite the CD6 binding site on hALCAM. These findings provide a molecular rationale for the observed cross-species CD6/ALCAM interaction and the apparent inability to generate monoclonal antibodies (mAb) against the CD6 binding site. RNA blot analysis showed that mRNA transcripts encoding mALCAM are expressed in the brain, lung, liver, and the kidney, as well as by activated leukocytes and a number of cell lines. A rat mAb specific for mALCAM was produced and by two-color immunofluorescence studies was shown to bind to both activated CD4+ and CD8+ T cells.

Greater emotional distress is associated with accelerated CD4+ cell decline in HIV infection

An investigation was conducted to explore the relationship between emotional distress and HIV progression. One hundred twenty-five homosexual, HIV-positive males participated in a 12-month longitudinal investigation. Psychosocial data were collected at 6-month intervals and CD4+ data were collected from diagnosis to the end of the investigation. Principal component analyses were performed initially to identify factors of emotional distress and health status. In addition, CD4+ reliability assessments were performed to ensure the validity of the prognostic assessments made. As a result of these analyses, 47 individuals were eligible for the main analyses. The results from a stepwise regression revealed that disease progression was significantly predicted by CD4+ count at diagnosis (32% of variance) and emotional distress (17% of variance), but was unrelated to subjective perceptions of health. The data suggest that some of the variability in HIV progression can be attributed to emotional distress.

Structure and chromosomal location of the human CD6 gene: detection of five human CD6 isoforms

The CD6 protein has been shown to play important roles in T cell costimulation and adhesion. Recently, variably spliced isoforms of CD6 mRNA have been identified in both human and murine T cells. Here we report on the genomic organization of the human CD6 gene, its chromosomal localization, and the characterization of novel isoforms. Human CD6 is encoded by at least 13 exons. The amino terminal signal sequence, extracellular region, and transmembrane domain are encoded by seven exons, while the cytoplasmic domain of CD6 is encoded by six exons. Each of the three extracellular scavenger receptor cysteine-rich domains is encoded by a separate exon. Fluorescence in situ hybridization studies and screening of a chromosome-specific YAC (yeast artificial chromosome) library revealed that the gene encoding CD6 is located on chromosome 11 at 11q13 in close proximity to the gene encoding the related molecule CD5 and within 600 kb of CD20. Analysis of mRNA transcripts encoding CD6 isolated from mitogen-activated PBMC and from B cells obtained from patients with chronic lymphocytic leukemia revealed the presence of at least five different CD6 transcripts. These transcripts arise via variable splicing of exons encoding the cytoplasmic domain of CD6. The existence of these isoforms suggests that signaling through CD6 could be regulated via alternative splicing of cytoplasmic encoding exons.

Structure and chromosomal location of the human CD6 gene: detection of five human CD6 isoforms

The CD6 protein has been shown to play important roles in T cell costimulation and adhesion. Recently, variably spliced isoforms of CD6 mRNA have been identified in both human and murine T cells. Here we report on the genomic organization of the human CD6 gene, its chromosomal localization, and the characterization of novel isoforms. Human CD6 is encoded by at least 13 exons. The amino terminal signal sequence, extracellular region, and transmembrane domain are encoded by seven exons, while the cytoplasmic domain of CD6 is encoded by six exons. Each of the three extracellular scavenger receptor cysteine-rich domains is encoded by a separate exon. Fluorescence in situ hybridization studies and screening of a chromosome-specific YAC (yeast artificial chromosome) library revealed that the gene encoding CD6 is located on chromosome 11 at 11q13 in close proximity to the gene encoding the related molecule CD5 and within 600 kb of CD20. Analysis of mRNA transcripts encoding CD6 isolated from mitogen-activated PBMC and from B cells obtained from patients with chronic lymphocytic leukemia revealed the presence of at least five different CD6 transcripts. These transcripts arise via variable splicing of exons encoding the cytoplasmic domain of CD6. The existence of these isoforms suggests that signaling through CD6 could be regulated via alternative splicing of cytoplasmic encoding exons.

Clinical practice guidelines in pediatric and newborn medicine: implications for their use in practice

Clinical practice guidelines are becoming pervasive in pediatrics and newborn medicine. They have spanned a wide range of primary care practice parameters from treating otitis media with effusion, to performing complex surgery for congenital heart disease, and management of respiratory distress syndrome and coordinating discharge from the neonatal intensive care unit. Administrators believe that using clinical practice parameters reduces health care costs, improves quality of care, and limits malpractice liability. Practice parameters and guidelines have grown in use because powerful interests-third-party payers, insurers, and health maintenance organizations, as well as hospital administrators bent on reducing variable costs of care and contracting for capitated care-champion their development, implementation, and monitoring. Economic credentialing of physicians with excessive variances without risk-adjusting for other than average patients is problematic and remains unchecked partly because of the fundamental characteristics of the evolving health care industry in which costs are more easily measured than quality. For highly autonomus physicians this standardization of medical decision making may represent a difficult transition into corporate practice by realigning traditional values of the doctor-patient relationship. However, because guidelines are almost certainly here to stay, pediatricians and neonatologists need to think critically about how their content and method of implementation, monitoring, and modification may influence medical teaching and decision making in the future. If guidelines are introduced primarily as a cost savings or containment tool that ignores the impact on the quality of care and restricts necessary care for infants and children, especially those with chronic illness or who are developmentally at risk, then neonatologists and pediatricians must be quick and determined to challenge the potentially damaging use of practice parameters or guidelines. Furthermore, there are many medicolegal implications of guideline implementation that may not favor physicians and leave to hospitals, insurers, and ultimately the courts decisions regarding evidence-based practice. In this review article, we pay special attention to the guidelines developed in newborn medicine. We discuss why and how guidelines are developed and critically evaluate the available evidence describing potential benefits and drawbacks of guidelines in general. There are legal implications to the implementation of guidelines, and guidelines may increase provider susceptibility to malpractice allegations. Neonatologists and pediatricians should critically analyze the following questions when guidelines are being developed: Are clinical practice parameters the most effective means to reduce the costs of health care, or improve the quality of health care services while reducing the need for and protecting physicians from malpractice suits? Or do clinical practice guidelines more closely resemble an audit system developed by health care organizations, insurers, and others including government-sponsored health care to appease powerful interests-with limited evidence for promise and perhaps potential negative cost, quality, and malpractice liability implications? In pediatric and newborn medicine there is limited evidence that guidelines have achieved the desired goals and further analysis of their process of care and the costs of implementation is warranted.

Administration of peripheral parenteral nutrition: a prospective study comparing rotation of venous access sites with ultrafine cannulas

Peripheral veins have been used successfully for patients requiring short- to medium-term total parenteral nutrition. This study prospectively compares two methods of peripheral parenteral nutrition (PPN). Forty-six patients requiring parenteral nutrition (PN) were identified prospectively. Fifty courses of PPN were prescribed using a standardized PPN formula of 9.3 g nitrogen, 1400 kCal, 2500 ml (KABI II, Pharmacia). Patients were randomized to receive PPN via 23G, 15 cm flexane catheters (Nutriline) inserted into an antecubital vein which remained in-situ with a continuous infusion over 24 h, or to receive 12-h cyclical infusions through peripherally sited 18G catheters (Venflon) which were removed postinfusion and reinserted into the contralateral forearm on alternate days. Data collected included duration, complications and cost of materials for each prescribed course. A scoring system to determine patient anxiety and depression and a questionnaire regarding patients' perspectives were evaluated. Fifty courses were prescribed, 26 by rotation of veins (RV) and 24 by Nutriline (N). Mean duration of feeding was 7.9 and 8.6 days, respectively; cost of materials were comparable 6.48/day (RV) vs 5.17/day (N); 2 RV patients failed to complete their course (no access [P< 0.05], whilst 9 N patients failed to complete their course (4 severe phlebitis, 2 no venous access, 2 septicaemia, 1 dislodged). Five patients required CPN (RV, N 3) while 4 remaining patients were fed by an alternative PPN method. The overall incidence of anxiety was 20% and of depression 16%, with no significant difference between groups. The majority of patients (87%) found mobility restricted. Twelve-hourly infusions via alternate forearm veins were significantly more successful than continuous infusions via Nutriline, both in terms of completion of the prescribed course and less venous morbidity. This study confirms that rotation of forearm veins allows affordable and successful PN administration to the majority of patients, with low PN-related morbidity.

Two amino acid differences in the sixth transmembrane domain are partially responsible for the pharmacological differences between the 5-HT1D beta and 5-HT1E 5-hydroxytryptamine receptors

5-Hydroxytryptamine elicits its physiological effects by interacting with a diverse group of receptors. Two of these receptors, the 5-HT1D beta and the 5-HT1E receptors, are approximately 60% identical in the transmembrane domains that presumably form the ligand binding site yet have very different pharmacological properties. Analysis of the pharmacological properties of a series of chimeric 5-HT1D beta/5-HT1E receptors indicates that sequences in the sixth and seventh transmembrane domains are responsible for the differential affinity of 5-carboxamidotryptamine for these two receptors. More detailed analysis shows that two amino acid differences in the sixth transmembrane domain (Ile333 and Ser334 in the 5-HT1D beta receptor, corresponding to Lys310 and Glu311 in the 5-HT1E receptor) are largely responsible for the differential affinities of some, but not all, ligands for the 5-HT1D beta and 5-HT1E receptors. It is likely that these two amino acids subtly determine the overall three-dimensional structure of the receptor rather than interact directly with individual ligands.

Prospective study of the aetiology of infusion phlebitis and line failure during peripheral parenteral nutrition

Four techniques of administering peripheral parenteral nutrition (PPN) were examined prospectively to investigate the role of mechanical trauma in the development of infusion phlebitis. Patients in group 1 (n = 15) were fed via a standard 18-G Teflon cannula which was removed on completion of the infusion and was rotated to the contralateral arm every day. Group 2 patients (n = 15) had a similar catheter sited in each forearm simultaneously, with rotation of the side of infusion each day. Patients in group 3 (n = 17) had a 15-cm Silastic rubber catheter inserted into a forearm vein and a standard cannula sited in the contralateral forearm, with alternation of infusion each day. Those in group 4 (n = 13) had a fine-bore 23-G silicone catheter sited in one arm only. Patients in groups 1, 2 and 3 were fed over 12-h cycles and those in group 4 for a 24-h continuous cycle. A total of 408 patient-days of PPN were given. Mean duration of PPN in groups 1-4 was 7.5, 9, 5.5 and 5 days respectively. Infusion phlebitis was not recorded in patients who had a daily change of cannula (group 1), but occurred in four patients in group 2, eight in group 3 and eight in group 4. Phlebitis scores were 0, 9, 15 and 12 for groups 1-4 respectively. Severe phlebitis and line occlusion occurred more frequently in patients with a 15-cm catheter (group 3) and in those fed continuously over 24 h (group 4). These results suggest that mechanical trauma is an important factor in the aetiology of infusion phlebitis. This can be minimized by reducing the time for which the vein wall is exposed to nutrient infusion and by reducing the amount of prosthetic material within the vein.

Clinical applications of a new parenteral antibiotic in the treatment of severe bacterial infections

Cephalosporins are one of the mainstays of antibiotic therapy, and third-generation cephalosporins are first-line agents for the treatment of many types of serious infections, including those of nosocomial origin. Gaps in activity of currently available third-generation cephalosporins such as cefotaxime, cefoperazone, ceftriaxone, and ceftazidime, and increasing reports of gram-negative bacilli resistance to some of these agents, especially Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter spp., make it necessary to investigate new compounds. Cefepime, a fourth-generation cephalosporin with a wide range of activity against gram-positive and gram-negative bacteria, including multi-resistant strains of Enterobacteriaceae, was evaluated in comparison with ceftazidime for the treatment of serious infections in hospitalized patients. Ceftazidime is a commonly prescribed third-generation cephalosporin used for empiric treatment of serious infections such as pneumonia, urinary tract infection, and skin and skin-structure infection. This investigation was an open, randomized comparative study involving 882 patients in North America. Cefepime 2 g every 12 hours demonstrated similar efficacy to that of ceftazidime 2 g every 8 hours for the treatment of pneumonia and urinary tract infection (including cases associated with concurrent bacteremia), and skin and skin-structure infections. The bacteriologic responses were generally >85%. The most common pathogens isolated were Escherichia coll, Streptococcus pneumoniae, P. aeruginosa, K. pneumoniae, Haemophilus influenzae, Staphylococcus aureus, and Streptococcus, group B. Overall, approximately 94% of pathogens isolated in pretreatment cultures were susceptible to cefepime and ceftazidime. Cefepime and ceftazidime were well tolerated; only 3% of patients in each group discontinued therapy because of an adverse event. The most common adverse events were headache, diarrhea, nausea, vomiting, pruritus, and rash. The results of this study indicate that cefepime is a promising, effective, and safe single-agent therapy for serious infections in hospitalized patients.

Early signal transduction by the receptor to the chemokine monocyte chemotactic protein-1 in a murine T cell hybrid

Members of the C-C family of chemotactic cytokines promote chemotaxis and adhesion of leukocytes. In this study, we have identified a murine T cell hybrid that expresses receptors to the chemotactic cytokine monocyte chemotactic protein-1 (MCP-1). This cell line was used to examine MCP-1 receptor-mediated signal transduction events in a homologous system in the absence of interference with other receptors. Our results show that in the 3B4 M1.9 T cell hybrid, MCP-1 receptors mediate intracellular calcium mobilization and extracellular calcium import without detectable increases in total water-soluble inositol phosphates. In addition, MCP-1 regulates the tyrosine phosphorylation of specific substrates at 42 and 44 kDa and induces mobility shift of p42/44 mitogen-activated protein kinases. MCP-1-mediated calcium responses, tyrosine phosphorylation, and the electrophoretic mobility shift of p42/44 mitogen-activated protein kinases can be inhibited by pretreatment of cells with pertussis toxin, indicating a role for Gi-like G proteins in coupling the MCP-1R to signal transduction.

Early signal transduction by the receptor to the chemokine monocyte chemotactic protein-1 in a murine T cell hybrid

Members of the C-C family of chemotactic cytokines promote chemotaxis and adhesion of leukocytes. In this study, we have identified a murine T cell hybrid that expresses receptors to the chemotactic cytokine monocyte chemotactic protein-1 (MCP-1). This cell line was used to examine MCP-1 receptor-mediated signal transduction events in a homologous system in the absence of interference with other receptors. Our results show that in the 3B4 M1.9 T cell hybrid, MCP-1 receptors mediate intracellular calcium mobilization and extracellular calcium import without detectable increases in total water-soluble inositol phosphates. In addition, MCP-1 regulates the tyrosine phosphorylation of specific substrates at 42 and 44 kDa and induces mobility shift of p42/44 mitogen-activated protein kinases. MCP-1-mediated calcium responses, tyrosine phosphorylation, and the electrophoretic mobility shift of p42/44 mitogen-activated protein kinases can be inhibited by pretreatment of cells with pertussis toxin, indicating a role for Gi-like G proteins in coupling the MCP-1R to signal transduction.

Intraosseous infusion--a technique available for intravascular administration of drugs and fluids in the child with burns

Intraosseous infusion is a potential route for intravenous access in the child with burns who required vascular access that cannot be achieved in a timely manner via another route. Drugs, fluid and blood can be given via this route and marrow aspirate drawn for laboratory analysis. It is a reliable, safe procedure with a low incidence of complications.

The management of dysphagia in stroke

People who have strokes suffer a variety of problems, depending on the site and severity of brain damage. A particularly unpleasant and dangerous one is dysphagia which, if not properly assessed and managed, can prevent the patient receiving adequate nutrition to enable him or her to participate fully in a rigorous rehabilitation programme, or which may even cause his or her death through aspiration of food. The authors describe an appropriate nursing response to the problem, and advocate a multidisciplinary approach to the management of nutrition in the care of patients with strokes.

Nitrate and nitric acid concentrations at two Rocky Mountain baseline monitoring sites

A two-tiered, Teflon/nylon filterpack system was used to characterize spatial and temporal patterns of particulate nitrates and nitric acid vapors at two monitoring sites in the Rocky Mountains. Geometric means for particulate nitrates were 38.9 and 52.8 ng/m(3) for the upper and lower sites, respectively. For nitric acid, geometric means of 70.4 ng/m(3) for the upper site and 295 ng/m(3) for the lower site were observed. The relatively low concentrations found at these two sites are comparable to published values for these materials at other remote sites. Atmospheric concentrations of nitrates and nitric acid were correlated significantly at each site, and the total nitrate concentrations (NO(3)(-) plus HNO(3)) were correlated between sites. Comparisons between the two sites indicate that nitric acid concentrations were statistically greater at the lower elevation site, whereas nitrate concentrations were not significantly different. No general seasonal or annual pattern of nitrate or nitric acid concentrations were evident when comparable sampling periods were examined.

Histopathologic changes following irradiation for uveal tract melanoma

Histopathologic studies were performed on 38 eyes in patients with uveal melanoma who had enucleation. Of the 38 eyes examined, enucleation was required in 11 (29%) following episcleral radioactive plaque therapy (RPT), which was performed in 83 patients. The reasons for enucleation in the 11 patients who had RPT were progressive tumor in 5 and treatment complications in 6 eyes. The histologic findings in these 11 patients were compared to those seen in 7 patients (18%) who received a planned course of preoperative external beam radiotherapy (RT) prior to enucleation and with 20 uveal melanoma patients (53%) who were treated with enucleation alone. Tumor necrosis was found in the eyes of patients from all three groups examined. It was, however, seen more frequently and to a greater extent in the 11 RPT patients as compared to the 7 preoperative RT and 20 enucleation alone patients, p = .01. There was no difference in the incidence or extent of tumor necrosis in the 7 preoperative RT patients as compared to the 20 primary enucleation patients, p = .18. In all 3 study groups, no correlation was found between tumor size and necrosis. In the 11 RPT patients, necrosis was independent of cell type and the radiation dose. As expected, the RPT patients had a greater incidence of neovascularization on the iris and scleral necrosis than those of the other two study groups (70 vs. 12.5% and 33 vs 0%, respectively), p = .004. A major effort needs to be made to optimize episcleral RPT in order to reduce treatment complications and increase the incidence of primary tumor control.

Characterization of the genes controlling the biosynthesis of the polyketide phytotoxin coronatine including conjugation between coronafacic and coronamic acid

Pseudomonas syringae pv. glycinea PG4180 produces a chlorosis-inducing phytotoxin, coronatine (COR), which consists of a polyketide component, coronafacic acid (CFA), which is coupled via amide bond formation to coronamic acid (CMA), an ethylcyelopropyl amino acid (aa) derived from isoleucine. P. syringae pv. syringae strains PS51 and PS61, which do not synthesize coronafacoyl compounds (conjugates between CFA and aa), acquired the ability to produce CFA and COR when transformed with p4180A, a 90-kb indigenous plasmid in PG4180. Tn5 mutagenesis indicated that the COR biosynthetic genes in PG4180 are clustered within a 30-kb region on p4180A. The phenotype of selected COR-defective mutants was determined by supplying them with CFA and CMA and by complementation studies with cloned DNA from the COR biosynthetic cluster. Using this approach, the regions encoding CFA and CMA synthesis and coupling activity were localized to the 24-, 12.5- and 2.3-kb regions of the cluster, respectively. Mutants in a 6-kb region required the addition of both CFA and CMA for COR synthesis, which may indicate a regulatory role for this part of the cluster. PS51 and PS61 transconjugants containing cloned DNA from the coupling region produced COR when supplied with CFA and CMA, indicating that coupling activity was cloned and expressed in bacteria lacking the COR biosynthetic cluster.

A deletion mutation in the third cytoplasmic loop of the mouse m1 muscarinic acetylcholine receptor unmasks cryptic G-protein binding sites

Mutations were introduced in the highly conserved carboxyl-terminal region of the third cytoplasmic loop of the mouse m1 muscarinic acetylcholine receptor (mAChR) gene by site-directed mutagenesis. The effects of these mutations on ligand binding and on mAChR coupling to phosphoinositide turnover have been examined following expression in mouse Y1 adrenal carcinoma cells, Chinese hamster ovary (CHO) cells, and Rat-2 fibroblasts. Point mutations in the region proximal to the sixth transmembrane domain had no effect on antagonist binding but did result in decreased agonist affinity. A deletion of four amino acids in the same region effectively uncoupled the receptor from phosphoinositol turnover in Y1 adrenal carcinoma cells but had no effect in either CHO cells or Rat-2 fibroblasts. Differential sensitivity to pertussis toxin indicates that the m1 mAChR can interact with multiple G-proteins in CHO cells and Rat-2 cells via distinct recognition sites on the receptor. These data demonstrate multiple G-proteins can interact with an individual receptor, that the same receptor may couple to different second messenger pathways, and that these responses can vary in a cell type-specific manner.

Movement disorders and psychological tests of frontal lobe function in schizophrenic patients

Neuropsychological tests of frontal lobe functions were undertaken in 46 chronic schizophrenic patients who were also rated for movement disorders. Tardive dyskinesia was found to have significant associations with most of these psychological tests. The possible mechanisms are discussed within the context of known neostriatal psychological functions.