5-Aminosalicylic acid abrogates T-cell proliferation by blocking interleukin-2 production in peripheral blood mononuclear cells

The antiinflammatory agent sulfasalazine (SS) is prescribed to treat Crohn's disease, ulcerative colitis and rheumatoid arthritis. Activated T cells are present within diseased mucosal and synovial sites. We tested whether SS or its metabolites 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP) inhibited the T-cell activation products interleukin 2 (IL-2) and interleukin 2 receptor alpha-chain (IL-2R alpha). Experiments were performed in phytohemaglutinin- and phorbol ester-stimulated peripheral blood mononuclear cells. Radioactive thymidine and leucine incorporation assayed DNA and protein synthesis, respectively. Enzyme-linked immunosorbent assay and Northern blot analysis measured IL-2 and IL-2R alpha. Lactate dehydrogenase release determined cell viability, and intracellular free calcium was measured by an indole fluorescent indicator. SS and 5-ASA, but not SP, inhibited T-cell proliferation and protein synthesis in phytohemaglutinin- and phorbol ester-stimulated peripheral blood monomuclear cells. 5-ASA (625 microM) markedly reduced culture supernatant IL-2 protein levels by 92% and steady-state IL-2 messenger RNA levels 4.4-fold at 24 and 18 hr, respectively. The supplementation of IL-2 restored T-cell proliferation only in 5-ASA-treated cultures. SS, 5-ASA and SP did not alter intracellular calcium accumulation after mitogenic stimulation. SS and 5-ASA (625 microM) caused 71% and 37% cytotoxicity, respectively, in 72-hr cultures. 5-ASA inhibits T-cell proliferation in part by blocking IL-2 messenger RNA accumulation and protein production downstream of the rise in cytosolic calcium. Inhibition of IL-2 production is an additional mechanism of action for 5-ASA.

Structure and mechanism of galactose oxidase. The free radical site

Crystallographic and spectroscopic studies on galactose oxidase have shown that the active site involves a free radical on tyrosine 272, one of the ligands coordinated to the Cu2+ cofactor. A novel thioether bond between tyrosine 272 and cysteine 228, and a stacking tryptophan 290, over this bond, are features of the crystal structure. The present study describes the development of a high level heterologous expression system for galactose oxidase and the construction of mutational variants at these key active site residues. The expressed wild-type enzyme and mutational variants (W290H and C228G) have been characterized by x-ray crystallography, visible spectroscopy, and catalytic activity measurements. A further variant protein, Y272F, could not be purified. The data establish that the thioether bond and stacking tryptophan are essential for activity and further support a role for tryptophan 290 as a component of the free radical site.

Distribution of dominant T cell receptor beta chains in human intestinal mucosa

The majority of human intestinal intraepithelial lymphocytes (iIELs) are CD8+ T cells that use the T cell receptor (TCR)-alpha/beta. Previous studies have shown that iIELs isolated from segments of small intestine or colon contain one or several dominant alpha/beta T cell clones. It is not known whether these clones expand only locally in response to a particular antigen or whether they are widely distributed throughout the intestine. To address this question, iIELs were purified from near the proximal and distal margins in a series of intestinal resections for noninflammatory diseases. TCR-beta expression was then assessed by semiquantitative polymerase chain reaction amplification, analysis of N-region length, and DNA sequencing. The previously described oligoclonal expansion of iIELs was confirmed in each sample. Identical dominant clones were identified in the proximal and distal samples from most cases, including samples taken from sites as distant as the transverse and sigmoid colon or rectum. Distinct clones were found in only one case with samples from the terminal ileum and transverse colon. These results demonstrate that a relatively small number of widely dispersed T cell clones comprise the majority of cells in the human intestinal mucosa.

Ganciclovir: treatment of cytomegalovirus in immunocompromised individuals

Ganciclovir is synthetic antiviral agent that interferes with the CMV DNA synthesis. Administered intravenously, the antiviral drug can effectively stop the CMV herpes virus from replicating in adolescents and adults. CMV does pose a serious threat to immunocompromised individuals. Nursing care of patients receiving ganciclovir should include a complete assessment, predosing laboratory work and a complete drug and allergy history. Proper administration of ganciclovir, observation of side effects, and documentation are the responsibility of the nephrology nurse.

Human immunodeficiency virus type 1 mRNA expression in peripheral blood cells predicts disease progression independently of the numbers of CD4+ lymphocytes

To address the significance of human immunodeficiency virus (HIV) replication in peripheral blood mononuclear cells (PBMCs), we have used reverse transcriptase-initiated PCR to measure HIV-1 mRNA expression in PBMC specimens collected from a cohort of HIV-infected individuals during a long-term prospective study. We found dramatic differences in HIV mRNA expression among individuals with very similar clinical and laboratory indices, and this variation strongly correlated with the future course of the disease. No evidence of viral replication was detected in PBMCs from asymptomatic individuals who, thereafter, had normal levels of CD4+ cells for at least 5 years. Irrespective of whether the CD4+ cell numbers were normal at the time of sampling, abundant expression of HIV-1 mRNA in PBMCs predicted accelerated disease progression within the next 2 years. Thus, independently of what may be the rate of HIV replication in other viral reservoirs, such as lymphatic tissue, the amount of HIV mRNA in PBMCs appears to reflect the subsequent development of HIV disease. We have also used the reverse transcriptase-initiated PCR assay to demonstrate a transient response to 3'-azido-3'-deoxythymidine treatment. Determination of HIV-1 mRNA expression in the PBMCs of infected individuals could, therefore, have significant clinical utility as a prognostic indicator and as a means to guiding and monitoring antiviral therapies.

Modelling symmetry detection with back-propagation networks

This paper reports experimental data and results of network simulations in a project on symmetry detection in small 6 x 6 binary patterns. Patterns were symmetrical about the vertical, horizontal, positive-oblique, or negative-oblique axis, and were viewed on a computer screen. Encouraged to react quickly and accurately, subjects indicated axis of symmetry by pressing one of four designated keys. Detection times and errors were recorded. Back-propagation networks were trained to categorize the patterns on the basis of axis of symmetry, and, by employing cascaded activation functions on their output units, it was possible to compare network performance with subjects' detection times. Best correspondence between simulated and human detection-time functions was observed after the networks had been given significantly more training on patterns symmetrical about the vertical and the horizontal axes. In comparison with no pre-training and pre-training with asymmetric patterns, pre-training networks with sets of single vertical, horizontal, positive-oblique or negative-oblique bars speeded subsequent learning of symmetrical patterns. Results are discussed within the context of theories suggesting that faster detection of symmetries about the vertical and horizontal axes may be due to significantly more early experience with stimuli oriented on these axes.

Osteoclast function and its control

Bone resorption appears to be dependent on a range of processes. It requires an adequate number of osteoclasts to access bone mineral. These osteoclasts must be activated by a mechanism which is dependent upon prior osteoblastic stimulation. A range of factors then contribute to the formation of a functionally effective resorptive hemivacuole. These entail osteoclast adhesion to the bone surface leading to the formation of a sealing zone. Only then can subsequent processes such as H+ ion transport, enzyme secretion and matrix digestion become effective. Thus, any one process is potentially limiting to resorption and is a potential target for regulation. Long-range regulation takes place through the action of hormones, of which the mode of action of calcitonin has been the subject of recent investigations in isolated osteoclasts. Such studies have shown a possible involvement of distinguishable receptor subtypes, the occupancy of which may activate at least two types of triggering mechanism. It is likely that an eventual influence on motility properties through G protein mediation accounts for the actions of this hormone and of related peptides such as amylin and CGRP at the cellular level. Similar pathways may contribute to shorter range modulation of osteoclast activity by increases in ambient Ca2+. Finally, there is recent evidence for a contribution of endothelial cell-derived product to osteoclast regulation.

Application of Ultraviolet-C Light on Storage Rots and Ripening of Tomatoes

The application of ultraviolet light (UV-C, 254 nm) hormesis on fruits and vegetables to stimulate beneficial responses is a new method for controlling storage rots and extending the shelf-life of fruits and vegetables. The present study was aimed at treating tomatoes ( Lycopersicon esculentum ) with different UV-C dosages (1.3 to 40 KJ/m²) to induce resistance to black mold ( Alternaria alternata ), gray mold ( Botrytis cinerea ), and Rhizopus soft rot ( Rhizopus stolonifer ). These diseases were effectively reduced when tomatoes were inoculated following UV-C irradiation. UV-C treated tomatoes were firmer in texture and less red in color than the control tomatoes, indicating a delay in ripening. Slower ripening and resistance to storage rots of tomatoes are probably related. The positive effect of UV-C on tomatoes decreased as treatments were performed at stages of increased ripeness.

Cellular biology of bone resorption

Past knowledge and the recent developments on the formation, activation and mode of action of osteoclasts, with particular reference to the regulation of each individual step, have been reviewed. The following conclusions of consensus have emerged. 1. The resorption of bone is the result of successive steps that can be regulated individually. 2. Osteoclast progenitors are formed in bone marrow. This is followed by their vascular dissemination and the generation of resting preosteoclasts and osteoclasts in bone. 3. The exact pathways of differentiation of the osteoclast progenators to mature osteoclasts are debatable, but there is clear evidence that stromal cells support osteoclast generation. 4. Osteoclasts are activated following contact with mineralized bone. This appears to be controlled by osteoblasts that expose mineral to osteoclasts and/or release a factor that activates these cells. 5. Activated osteoclasts dissolve the bone mineral and digest the organic matter of bone by the action of agents secreted in the segregated microcompartments underlying their ruffled borders. The mineral is solubilized by protons generated from CO2 by carbonic anhydrase and secreted by an ATP-driven vacuolar H(+)-K(+)-ATPase located at the ruffled border. The organic matrix of the bone is removed by acid proteinases, particularly cysteine-proteinases that are secreted together with other lysosomal enzymes in the acid environment of the resorption zone. 6. Osteoclastic bone resorption is directly regulated by a polypeptide hormone, calcitonin (CT), and locally, by ionized calcium (Ca2+) generated as a result of osteoclastic bone resorption. 7. There is new evidence that osteoclast activity may also be influenced by the endothelial cells via generation of products including PG, NO and endothelin.

Validity and reliability of three methods used in the diagnosis of Raynaud's phenomenon. The UK Scleroderma Study Group

Three different assessment methods for the classification of Raynaud's phenomenon (RP) were compared. These were (i) a previously validated method using colour charts supplemented with a short questionnaire, (ii) answers to a questionnaire based on criteria derived from the consensus opinion of a group of clinicians, and (iii) individual clinician's assessment using standard descriptions based upon the same consensus view. We report the results of a study involving six clinicians and 30 subjects investigating the level of repeatability between the three methods and also the reliability between the six clinicians. There did not exist any overall systematic bias between the six clinicians. Further, agreement between them, as assessed by the kappa statistic, ranged from moderate to good. However, there did exist systematic bias between the results from all three of the classification approaches with agreement between them ranging from only poor to moderate. We conclude that the previously validated colour chart assessment is too insensitive to detect RP. Further, a structured questionnaire based on perceived clinician's opinion could not reproduce clinicians' classification in practice. By contrast, supplying clinicians with standard descriptions did yield a reliable classification system for RP.

Are clouds closing in on the Rochester miracle?

Though costs are low and access is high, the city's heralded health system hasn't escaped spiraling inflation. And doctors in the region are weary of making sacrifices.

Changes in progesterone and oestrogen receptor mRNA and protein during maternal recognition of pregnancy and luteolysis in ewes

This study characterized changes in levels of mRNA and protein for endometrial oestrogen receptors (ERs) and progesterone receptors (PRs) during luteolysis and maternal recognition of pregnancy. For cyclic and pregnant ewes, endometrium was collected on days 10, 12, 14, or 16 post-oestrus (4 ewes/day for each status) for the measurement of ER and PR mRNA and protein. The amount of receptor mRNA is expressed in relative units above background, measured from radiographs of dot-blot hybridization of total endometrial RNA with ER and PR cDNAs. At hysterectomy, jugular vein blood samples were collected and assayed for progesterone, total corpus luteum weight was recorded and, in vitro, endometrial oxytocin-stimulated inositol phosphate formation was estimated. In pregnant ewes, plasma progesterone increased gradually between days 10 and 16 (P < 0.01), corpus luteum weight was stable at approximately 0.8 g and oxytocin did not stimulate endometrial formation of inositol phosphates in vitro. In contrast, in cyclic ewes, plasma progesterone decreased from day 10 to day 16 (P < 0.01), corpus luteum weight decreased after day 14 to approximately 0.48 g (P = 0.05) and oxytocin stimulated an increase of approximately 1300% in the endometrial formation of inositol phosphates on day 16. cDNAs specifically hybridized with 1.6 and 3.1 kb transcripts for PR mRNA and a 6.5 kb transcript for ER mRNA. In cyclic ewes, the amount of PR mRNA increased from day 10 to maximum levels on days 14-16. The number of PRs decreased from day 10 (2.25 pmol/mg DNA) to day 12 (0.98 pmol/mg DNA) and then increased from day 14 to day 16 (2.8 pmol/mg DNA). In pregnant ewes, PR mRNA levels were greatest on days 10-12 and decreased by approximately 50% by day 16. In contrast, the number of PRs was relatively unchanged from day 10 to day 16 (1.53 to 1.03 pmol/mg DNA). In cyclic ewes, the amount of ER mRNA was lowest at day 10 and increased fivefold by day 16. The number of ERs remained relatively unchanged from day 10 to day 14 (6.07 pmol/mg DNA) and increased by day 16 (16.12 pmol/mg DNA). In pregnant ewes, ER mRNA decreased by approximately 80% from day 12 to day 16. Similarly, the number of ERs decreased from day 10 to day 16 (5.41 to 2.05 pmol/mg DNA). Correlations between ER mRNA and PR mRNA (r = 0.68), ERs and PRs (r = 0.50) and ER mRNA and ERs (r = 0.50) were high (P < 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)

Reliability of skin involvement measures in scleroderma. The UK Scleroderma Study Group

Two methods have been proposed to quantify the extent of skin involvement in scleroderma. These are (1) a scoring system which quantifies and summates this severity rating in 17 areas of skin surface and (2) a method estimating the percentage of skin involvement using a shaded manikin. We report on a study comparing the inter-observer reliability of these two approaches using the ratings of six clinicians on 12 patients. Systematic bias between observers was noted with both methods, but inter-observer agreement, as-assessed by the intraclass correlation coefficient (ICC), was higher with the score method. The manikin method resulted in a greater degree of disagreement between the observers, as well as a higher amount of random error, reflecting the difficulty of defining the bounds of abnormal skin. Despite the presence of bias, the score method is the preferred method for assessing the level of skin involvement.