Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Library Materials”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,585 records · Page 88Linked to original sources

Visible Human 2.0--the next generation.

The National Library of Medicine has initiated the development of new anatomical methods and techniques for the acquisition of higher resolution data sets, aiming to address the anatomical artifacts encountered in the development of the Visible Human Male and Female and to insure enhanced detection of structures, providing data in greater depth and breadth. Given this framework, we acquired a complete data set of the head and neck. CT and MR scans were also obtained with registration hardware inserted prior to imaging. The arterial and venous systems were injected with colorized araldite-F. After freezing, axial cryosectioning and digital photography at 147 microns/voxel resolution was performed. Two slabs of the specimen were acquired with a special tissue harvesting technique. The resulting tissue slices of the whole specimen were stained for different tissue types. The resulting histological material was then scanned at a 60x magnification using the Virtual Slice technology at 2 microns/pixel resolution (each slide approximately 75,000 x 100,000 pixels). In this data set, for the first time anatomy is presented as a continuum from a radiologic granularity of 1 mm/voxel, to a macroscopic resolution of .147 mm/voxel, to microscopic resolution of 2 microns/pixel. The hiatus between gross anatomy and histology has been assumed insurmountable, and until the present time this gap was bridged by extrapolating findings on minute samples. The availability of anatomical data with the fidelity presented will render it possible to perform a seamless study of whole organs at a cellular level and provide a testbed for the validation of histological estimation techniques. A future complete Visible Human created from data acquired at a cellular resolution, aside from its daunting size, will open new possibilities in multiple directions in medical research and simulation.

Computer Simulation↗

A 1.6-Mb P1-based physical map of the Down syndrome region on chromosome 21.

The Down syndrome (DS) region on chromosome 21, which is responsible for the main features of DS such as characteristic facial features, a congenital heart defect, and mental retardation, has been defined by molecular analysis of DS patients with partial trisomy 21. The 2. 5-Mb region around the marker D21S55 between D21S17 and ERG in 21q22 is thought to be important, although contributions of other regions cannot be excluded. In this region, we focused on a 1.6-Mb region between a NotI site, LA68 (D21S396, which is mapped distal to D21S17) and ERG, because analysis of a Japanese DS family with partial trisomy 21 revealed that the proximal border of its triplicated region was distal to LA68. We constructed P1 contigs with 46 P1 clones covering more than 95% of the 1.6-Mb region. A high-resolution restriction map using BamHI was also constructed for more detailed analysis. Our P1 contig map supplements other physical maps previously reported and provides useful materials for further analysis including gene isolation and sequencing of the DS region.

Base Sequence↗

Study of induced thermoluminescence in CVD diamond film by low-energy X-rays.

For diamond film the one-hit model that is used to interpret low-energy X-ray thermoluminescence (TL) will require some modifications. After the films were irradiated with a superficial X-ray machine with different peak voltages, a two-compartment model with three parameters, the target size, the microscopic saturation factor and the high-LET saturation factor, was used to more precisely describe the TL response to X-ray with energies down to 10 kV. The microdosimetric distribution was calculated using single-event Monte Carlo code developed by authors together with EEDL cross-section data library. Some mechanistic insight into the physical aspect of radiation interaction with solid detectors can be obtained. The sensitive size in diamond was found to be about 15 nm. The saturation of one group of sublevels combined with the activation of another group of sublevels caused the relative efficiency to have a local minimum near 20 keV. The relative efficiency becomes higher below 10 keV, which is similar to the increasing relative biological effectiveness when the linear energy transfer passing through a biological system increases. The similarity made this material to be a molecular-scale dosimeter in the future.

Cobalt Radioisotopes↗

Chemotherapy for metastatic carcinoma of the esophagus and gastro-esophageal junction.

BACKGROUND: More than 50% of patients with esophageal cancer have metastatic disease at presentation. The use of chemotherapy for this patient group is increasing with the intention of local and distant tumor control, improving quality of life and prolongation of survival. OBJECTIVES: To assess the effectiveness of a) chemotherapy versus best supportive care or b) different chemotherapy regimes against each other, in metastatic esophageal carcinoma. SEARCH STRATEGY: Searches were conducted on the Cochrane Central register of Controlled Trials--CENTRAL (which includes the Cochrane Upper Gastrointestinal and Pancreatic Diseases Group Trials Register) on The Cochrane Library (Issue 1 2004) MEDLINE (1966 to February 2004), EMBASE (1980 to February 2004) and Cancerlit. Reference lists from trials selected by electronic searching were handsearched to identify further relevant trials. Published abstracts from conference proceedings from the United European Gastroenterology Week (published in Gut) and Digestive Disease Week (published in Gastroenterology) were handsearched. The search was updated in February 2005 and February 2006. Members of the Cochrane UGPD Group, and experts in the field were contacted and asked to provide details of outstanding clinical trials and any relevant unpublished materials SELECTION CRITERIA: Randomized controlled trials comparing chemotherapy versus best supportive care, or different chemotherapy regimes against each other in patients with metastatic carcinoma of the esophagus or gastro-esophageal junction. DATA COLLECTION AND ANALYSIS: Two authors (MYVH/EJK) extracted data and assessed trial quality. Study authors were contacted to obtain subgroup results of patients with metastatic esophageal carcinoma. MAIN RESULTS: Only two RCTs with a total of 42 participants compared chemotherapy with best supportive care for metastatic esophageal cancer. No survival benefit was shown for chemotherapy treatment in these RCTs. Five RCTs with a total of 1242 participants compared different chemotherapy regimes. Due to variation in patient population and chemotherapy regimes, it was not possible to perform a formal pooled analysis. There was no consistent benefit of any specific chemotherapy regimen. AUTHORS' CONCLUSIONS: There is a need for well designed, adequately powered, phase III trials comparing chemotherapy versus best supportive care for patients with metastatic esophageal cancer. Chemotherapy agents with promising response rates and tolerable toxicity are cisplatin, 5-fluorouracil (5-FU), paclitaxel and antracyclins. Future trials comparing palliative treatment modalities should assess quality of life with validated quality of life measures.

Antineoplastic Combined Chemotherapy Protocols↗

Endoscopic mucosal resection for early gastric cancer.

BACKGROUND: The treatment of early gastric cancer (EGC) using an endoscopy, namely, endoscopic mucosal resection (EMR), has been adopted for about 20 years, but the effectiveness and the safety of the modality are still controversial. The quality of these trials has not been assessed systematically. OBJECTIVES: The purpose of this review was to compare the effectiveness and the safety of EMR with gastrectomy for the treatment of EGC. SEARCH STRATEGY: Searches were conducted on the Cochrane Central Register of Controlled Trials - CENTRAL (which includes the Cochrane Upper Gastrointestinal and Pancreatic Diseases Group Trials Register) on The Cochrane Library (Issue 1 2005) MEDLINE (1966 to March 2005) and EMBASE (1980 to March 2005), CINAHL (1985-March 2005) and CBM (Chinese BioMedical Database 1982 -2002). Reference lists from trials selected by electronic searching were handsearched to identify further relevant trials. Published abstracts from conference proceedings from the United European Gastroenterology Week (published in Gut) and Digestive Disease Week (published in Gastroenterology) were handsearched. Members of the Cochrane UGPD Group, and experts in the field were contacted and asked to provide details of outstanding clinical trials and any relevant unpublished materials SELECTION CRITERIA: All randomised controlled trials of EGC patients involving a treatment arm of EMR and a comparison arm of gastrectomy were to be included, but no RCTs were found. DATA COLLECTION AND ANALYSIS: Three reviewers (YP Wang, C Bennett and T Pan) independently assessed the eligibility of potential trials and extracted the data. MAIN RESULTS: There are no included randomised control trials for the systematic review. Available evidence derived from non-randomised controlled trials is discussed in the main text of this review. AUTHORS' CONCLUSIONS: There is a lack of randomised controlled trials in which EMR is compared with gastrectomy for EGC. There is a need for well designed randomised controlled trials to determine the effects of EMR compared to gastrectomy.

Gastrectomy↗

Click Chemistry: Diverse Chemical Function from a Few Good Reactions.

Examination of nature's favorite molecules reveals a striking preference for making carbon-heteroatom bonds over carbon-carbon bonds-surely no surprise given that carbon dioxide is nature's starting material and that most reactions are performed in water. Nucleic acids, proteins, and polysaccharides are condensation polymers of small subunits stitched together by carbon-heteroatom bonds. Even the 35 or so building blocks from which these crucial molecules are made each contain, at most, six contiguous C-C bonds, except for the three aromatic amino acids. Taking our cue from nature's approach, we address here the development of a set of powerful, highly reliable, and selective reactions for the rapid synthesis of useful new compounds and combinatorial libraries through heteroatom links (C-X-C), an approach we call "click chemistry". Click chemistry is at once defined, enabled, and constrained by a handful of nearly perfect "spring-loaded" reactions. The stringent criteria for a process to earn click chemistry status are described along with examples of the molecular frameworks that are easily made using this spartan, but powerful, synthetic strategy.

Journal Article↗

Identification of dyes on ancient Chinese paper samples using the subtracted shifted Raman spectroscopy method.

The Stein Collection in the British Library contains the Diamond Sutra, the world's oldest, dated, printed document. The paper of the Diamond Sutra and other documents from the Stein collection is believed to be dyed yellow by a natural extract, called huangbo, from the bark of Phellodendron amurense, which contains three major yellow chromophores: berberine, palmatine, and jatrorrhizine. Conservation of these documents requires definite information on the chemical composition of the dyes but no suitable, completely noninvasive analytical method is known. Here we report resonance Raman studies of a series of pure dyes, of plant materials and extracts, and of dyed ancient and modern paper samples. Resonance Raman spectroscopy is used to enhance the spectra of the dyes over the signals from the paper matrixes in which they are held. The samples all give resonance Raman spectra which are dominated by intense fluorescence, but by using SSRS (subtracted shifted Raman spectroscopy) we have obtained reliable spectra of the pure dyes, native bark from the Phellodendron amurense, modern paper dyed with huangbo extracted from this bark, and ancient paper samples. For both ancient paper samples whose pigment bands were detected, the relative intensities of the bands due to berberine and palmatine suggest that the ancient paper is richer in berberine than its modern counterpart. This is the first nondestructive in situ method for detection of these pigments in manuscripts, and as such has considerable potential benefit for the treatment of irreplaceable documents that are believed to be dyed with huangbo but documents on which conservation work cannot proceed without definite identification of the chemical compounds that they contain.

Luminescent Measurements↗

Analysis of chromosome aberrations by FISH and Giemsa assays in lymphocytes of cancer patients undergoing whole-body irradiation: comparison of in vivo and in vitro irradiation.

PURPOSE: To study the cytogenetic effects of fractionated radiotherapy in peripheral blood lymphocytes of five cancer patients. In vitro experiments were performed in parallel using the same dose range and a comparison was made of the induced frequencies of stable and unstable chromosome aberrations. The object was to clarify the use of an in vitro calibration curve for immediate and retrospective dosimetry in cases of radiation accidents. MATERIALS AND METHODS: Patients were exposed to 60Co gamma-rays at a single dose of 11.5 cGy each day up to a total dose of 57.5 cGy, given in 5 days. For measurement of chromosome aberrations, blood was collected from patients before irradiation and after each exposure. Blood taken before treatment was used as a control and for in vitro irradiation experiments in the dose range 8-50 cGy. Chromosome aberration frequency (stable as well as unstable) was determined using fluorescence in situ hybridization (FISH) assay with specific DNA libraries for chromosomes 1, 4 and 8 and a pancentromertic probe for the whole genome. Giemsa-stained preparations were used to score unstable aberrations following in vivo and in vitro exposure. RESULTS: A linear dose-response curve was determined for both dicentrics and translocations. The in vivo frequency of translocations was higher than for dicentrics. Dose-response curves generated for translocations following in vivo and in vitro irradiation yielded similar frequencies. In contrast, for dicentrics, in vitro irradiation yielded a higher frequency when compared with data generated following in vivo exposure. CONCLUSIONS: For dose reconstruction purposes, translocations frequency seems to be a more adequate end-point than the scoring of dicentrics. The established in vitro calibration curve for dicentrics may underestimate absorbed radiation dose in cases of protracted exposure.

Adult↗

[Consensus-based guidelines on prostate biopsy].

OBJECTIVE: To develop evidence-based and consensus-based guidelines, helping physicians to take decisions about diagnostic procedures for men wishing to undergo examination for detection of prostate cancer. MATERIAL AND METHODS: A panel of multidisciplinary Italian experts in urology, medical oncology, laboratory medicine, radiotherapy, pathology and methodologists for clinical trial (Mario Negri Institution) grouped together in 2002 to address specific questions relating to clinical controversies in prostate cancer diagnosis. A practitioners feedback survey by means of a questionnaire of 49 items was also conducted in 2003 to assess the great variability in all the aspects relating a prostate biopsy (PB). Experts reviewed relevant evidence, using CeVEAS scale, of the literature from 1966 to December 2004 (Medline, Embase, Cochrane library) before offering the discussion panel proposed guidelines for a given subset of questions. The discussion panel, which consisted of presenters and representatives from medical oncology, forensic medicine, radiotherapy, ethics, biochemistry and family practice medicine, took place on February 12, 2005 in Bologna. The panel deliberated to reach consensus on suggested guidelines. When evidence was insufficient, suggested guidelines represent the opinion of a cross-section of the presenters and discussion panel. RESULTS: Consensus was achieved regarding all the aspects relating PB. The final paper was approved by the jury, the panel of experts and the audience. A standardized guideline, containing a short version for physicians and a standardized patient information booklet, for nation-wide use was developed. In the final document it has been reported as following: Prostatic biopsy (PB) is recommended in all patients with a PSA> = 4.0 ng/ml (2,5 ng/ml in patients with positive family history), abnormal DRE and %FPSA < 10%. PSAD and PSAV are considered controversial predictive factors. Antibiotic prophylaxis with a fluoroquinolone, which can be omitted in cases of transperineal (TP) PB, is mandatory when using a transrectal (TR) approach. It is necessary to start the prophylaxis the day before and continued for 2-3 days after the procedure. Anaesthesia is mandatory in case of TP biopsy and strongly recommended in cases of TR PB (10 cc of periprostatic lidocaine injection rather than intrarectal lidocaine gel). The optimal PB scheme should include more than 6 cores (preferably 10-12 cores) weighted more laterally and apically. PB directed only to the hypoechoic lesion or standard sextant biopsy (Hodge's scheme) are considered obsolete. PB of the transition zone are mandatory only in cases of re-biopsy. A tru-cut needle with a diameter of 18 Fr. is recommended and a sandwich technique for core fixation informalin is considered the optimal approach. A PB should be repeated within 6-12 months in the following cases:1) First biopsy is inadequate (less than 6 cores, absence of prostatic cells on the cores), 2) in presence of HGPIN, ASAP or both on first PB, 3) in cases with persistently high levels of PSA (PSA > 10 ng/ml or PSA velocity > 0,75 ng/ml/year). PB after radiotherapy is not routinely indicated as well as biopsy of the vesico-urethral anastomosis after radical prostatectomy in patients with PSA failure. CONCLUSIONS: The suggested guidelines represent a reasonable diagnostic approach in patients to be submitted to PB, with the understanding that new data, subsequent findings, or other methodological considerations may lead to future modifications.

Biopsy↗

Eradication therapy for peptic ulcer disease in Helicobacter pylori positive patients.

BACKGROUND: Peptic ulcer disease is the cause for dyspepsia in about 10% of patients. 95% of duodenal and 70% of gastric ulcers are associated with Helicobacter pylori. Eradication of H pylori reduces the relapse rate of ulcers but the magnitude of this effect is uncertain. OBJECTIVES: The primary outcomes were the proportion of peptic ulcers healed initially and proportion of patients free from relapse following successful healing. Eradication therapy was compared to placebo or pharmacological therapies in H. pylori positive patients. Secondary aims included symptom relief and adverse effects. SEARCH STRATEGY: Searches were conducted on the Cochrane Central register of Controlled Trials - CENTRAL (which includes the Cochrane Upper Gastrointestinal and Pancreatic Diseases Group Trials Register) on The Cochrane Library (Issue 3 2002) MEDLINE (1966 to July 2002) and EMBASE (1980 to July 2002). Reference lists from trials selected by electronic searching were handsearched to identify further relevant trials. Published abstracts from conference proceedings from the United European Gastroenterology Week (published in Gut) and Digestive Disease Week (published in Gastroenterology) were handsearched. The search was updated in September 2003, November 2004 and November 2005. Members of the Cochrane UGPD Group, and experts in the field were contacted and asked to provide details of outstanding clinical trials and any relevant unpublished materials SELECTION CRITERIA: Randomised controlled trials of short and long-term treatment of peptic ulcer disease in H. pylori positive adults were analysed. Patients received at least one week of H pylori eradication compared with ulcer healing drug, placebo or not treatment. Trials were included if they reported assessment from 2 weeks onwards. DATA COLLECTION AND ANALYSIS: Data were collected on ulcer healing, recurrence, relief of symptoms and adverse effects. MAIN RESULTS: 63 trials were eligible. Data extraction was not possible in 7 trials, and 56 trials were included. In duodenal ulcer healing, eradication therapy was superior to ulcer healing drug (UHD) (34 trials, 3910 patients, relative risk [RR] of ulcer persisting = 0.66; 95% confidence interval [CI] = 0.58, 0.76) and no treatment (2 trials, 207 patients, RR = 0.37; 95% CI 0.26, 0.53). In gastric ulcer healing, no significant differences were detected between eradication therapy and UHD (14 trials, 1572 patients, RR = 1.25; 95% CI = 0.88, 1.76). In preventing duodenal ulcer recurrence no significant differences were detected between eradication therapy and maintenance therapy with UHD (4 trials, 319 patients, relative risk [RR] of ulcer recurring = 0.73; 95% CI = 0.42, 1.25), but eradication therapy was superior to no treatment (27 trials 2509 patients, RR = 0.20; 95% CI = 0.15, 0.26). In preventing gastric ulcer recurrence, eradication therapy was superior to no treatment (11 trials, 1104 patients, RR = 0.29; 95% CI 0.20, 0.42). AUTHORS' CONCLUSIONS: A 1 to 2 weeks course of H. pylori eradication therapy is an effective treatment for H. pylori positive peptic ulcer disease.

Adult↗

Assessment of molecularly imprinted sol-gel materials for selective room temperature phosphorescence recognition of nafcillin.

Sol-gel imprinted materials were prepared against nafcillin, a semisynthetic beta-lactamic antibiotic employed in the treatment of serious infections caused by penicillinase-producing staphylococci. Two approaches were addressed for preparation of the imprinted materials and the controls: as conventional monoliths, which were ground and sieved to a desired particle size for rebinding analysis, and as films on supporting glass slides. The specific binding sites that are created during the imprinting process are analyzed via selective room temperature phosphorescence (RTP) (sol-gel films) measurements as well as via competitive room temperature phosphorescence ligand assay. Results demonstrated the importance of the physical configuration of the imprinted material for minimizing non-specific binding. The close similarities between the structures of different beta-lactamic antibiotics made it possible to interpret the roles of the template structure on specific molecular recognition. In this article, we introduce the use of room temperature phosphorescence as selective transduction method for the template. The imprinted sol-gel films displayed enhanced specific binding characteristics respect to the monolithic sol-gel and can be envisaged for the use as recognition matrices for the screening and rapid selection of antibiotics from a combinatorial library or for the rapid control of nafcillin in biological samples (e.g. milk, serum, urine).

Gels↗

Protein-dependent ribozymes report molecular interactions in real time.

Most approaches to monitoring interactions between biological macromolecules require large amounts of material, rely upon the covalent modification of an interaction partner, or are not amenable to real-time detection. We have developed a generalizable assay system based on interactions between proteins and reporter ribozymes. The assay can be configured in a modular fashion to monitor the presence and concentration of a protein or of molecules that modulate protein function. We report two applications of the assay: screening for a small molecule that disrupts protein binding to its nucleic acid target and screening for protein protein interactions. We screened a structurally diverse library of antibiotics for small molecules that modulate the activity of HIV-1 Rev-responsive ribozymes by binding to Rev. We identified an inhibitor that subsequently inhibited HIV-1 replication in cells. A simple format switch allowed reliable monitoring of domain-specific interactions between the blood-clotting factor thrombin and its protein partners. The rapid identification of interactions between proteins or of compounds that disrupt such interactions should have substantial utility for the drug-discovery process.

Amino Acid Sequence↗

Amino acid sequences of Euglena viridis ferredoxin and cytochromes c.

The Order Euglenida comprises many species and perhaps 40 genera, but almost all biochemical and genetic studies have been limited to a single species. Euglena gracilis, because of its ease of growth in the laboratory. Sequence studies of chloroplast and mitochondrial proteins from E. gracilis show that they have diverged widely from other eukaryotic lines. In the present paper we report the sequences of three proteins from another euglenoid, Euglena viridis, using material isolated from a natural bloom. The mitochondrial cytochrome c shows more than 90% sequence identity with that from E. gracilis, and contains the same characteristic features. The chloroplast cytochrome c6 has diverged to a greater extent and shows only 77% identity. The chloroplast ferredoxin from E. viridis is similar in sequence to those of cyanobacteria and algal chloroplasts, with sequence identities of up to 75%. Details of the purification, analysis and sequence determination experiments on the peptides have been deposited as Supplementary Publication SUP 50163 (32 pages) at the British Library Document Supply Centre, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1991) 273, 5.

Amino Acid Sequence↗

Improving interoperability between microbial information and sequence databases.

BACKGROUND: Biological resources are essential tools for biomedical research. Their availability is promoted through on-line catalogues. Common Access to Biological Resources and Information (CABRI) is a service for distribution of biological resources and related data collected by 28 European culture collections. Linking this information to bioinformatics databanks can make the collections' holdings more visible after a search in molecular biology databanks and vice-versa. Identification of links to sequence databases can be useful, but annotation and indexing problems, together with compilation errors, immediately arise. In this paper, we present our efforts for the identification of cross-references between CABRI catalogues and the EMBL Data Library and related results. RESULTS: An SRS site with both EMBL and CABRI catalogues has been set up. Ad-hoc changes in indexing scripts allowed to achieve homogeneous index keys and SRS link features have been used to identify links between databases. After manual checking and comparison with an alternative procedure, about 67,500 valid cross-references were identified, added to the EMBL Data Library and are now distributed with it. HTML links can be established from EMBL to CABRI network service. Procedures can be executed whenever needed. CONCLUSION: Links between EMBL and CABRI catalogues constitute an improved access to micro-organisms of certified quality and can produce positive effects on biomedical research. Further links between CABRI catalogues and other bioinformatics databases can now easily be defined by using these cross-references. Linking genetic information onto natural resources information may stand model for the integration of other databases containing empirical data on these materials.

Base Sequence↗

Gene expression profiles of pancreatic cancer and stromal desmoplasia.

Gene expression studies were undertaken in normal pancreas and pancreatic adenocarcinomas to determine new candidate genes that can potentially be used as markers of the disease. The characteristic desmoplastic stromal reaction of pancreatic adenocarcinoma greatly hampers expression studies in this tumour type, and usually necessitates time-consuming tissue microdissection for enrichment of the tumour cell population. We show that fine needle aspiration of cancer provides a fast and efficient way of obtaining samples highly enriched in tumour cells with sufficient yields of RNA. Using Atlas cancer cDNA arrays with 588 cancer-related genes, we describe gene expression profiles of normal pancreas, bulk pancreatic tumour tissues and pancreatic tumour aspirates containing more than 95% tumour cells. Analysis of bulk tissue specimens revealed differentially expressed genes belonging predominantly to the stromal component of the tumour. This contrasted with the results obtained from tumour-cell enriched samples. Several genes already described in pancreatic cancer (caspase 8, TIMP1, CD9, IL-13) were also differentially expressed in our study. Furthermore, we found dysregulated expression of genes not previously associated with pancreatic adenocarcinoma, such as Rac 1, GLG1, NEDD5, RPL-13a, RPS9 and members of the Wnt5A gene family. In summary, we present a panel of genes newly identified in the pathogenesis of pancreatic adenocarcinoma and demonstrate that fine needle aspirates of the tumour mass are a convenient source of material for gene expression studies in tumours accompanied by desmoplastic reactions.

Adaptor Proteins, Signal Transducing↗

Activation of mouse T-helper cells induces abundant preproenkephalin mRNA synthesis.

Antigenic or mitogenic stimulation of T cells induces the secretion of an array of protein hormones that regulate immune responses. Molecular cloning has contributed strongly to our present understanding of the nature of this regulation. A complementary DNA (cDNA) library prepared from a cloned concanavalin A-activated mouse T-helper cell line was screened for abundant and induction-specific cDNA's. One such randomly chosen cDNA was found to encode mouse preproenkephalin messenger RNA (mRNA). Preproenkephalin mRNA represented about 0.4 percent of the mRNA in the activated cell line but was absent in resting cells of this line. Other induced T-helper cell lines have 0.1 to 0.5 percent of their mRNA as preproenkephalin mRNA. Induced T-helper cell culture supernatants have [Met]enkephalin-immunoreactive material. The production by activated T cells of a peptide neurotransmitter identifies a signal that can potentially permit T cells to modulate the nervous system.

Animals↗

Surface-functionalized nanoparticle library yields probes for apoptotic cells.

We have developed techniques for the efficient synthesis and screening of small libraries of surface-functionalized nanoparticles for the recognition of specific types of cells. To illustrate this concept we describe the development of a nanoparticle that preferentially recognizes apoptotic Jurkat cells in a manner similar to the apoptosis-recognizing protein annexin V. The nanoparticle, which is detectable by fluorescence or NMR relaxometry, was analyzed for the ability to recognize normal and apoptotic cells by fluorescence-activated cell sorting (FACS) analysis and fluorescence microscopy. The capability to develop nanoparticles which interact with specific target cells could be applied to the design of materials for diverse applications including quantum dots, which serve as fluorescence tracers, colloidal gold, which serves as a tracer for electron micrographs, or the crystalline forms of drugs.

Apoptosis↗

The Nir1 locus in barley is tightly linked to the nitrite reductase apoprotein gene Nii.

pBNiR1, a cDNA clone encoding part of the barley nitrite reductase apoprotein, was isolated from a barley (cv. Maris Mink) leaf cDNA library using the 1.85 kb insert of the maize nitrite reductase cDNA clone pCIB808 as a heterologous probe. The cDNA insert of pBNiR1 is 503 bp in length. The nucleotide coding sequence could be aligned with the 3' end of other higher plant nitrite reductase apoprotein cDNA sequences but diverges in the 3' untranslated region. The whole-plant barley mutant STA3999, previously isolated from the cultivar Tweed, accumulates nitrite after nitrate treatment in the light, has very much lowered levels of nitrite reductase activity and lacks detectable nitrite reductase cross-reacting material due to a recessive mutation in a single nuclear gene which we have designated Nir1. STA3999 has the characteristics expected of a nitrite reductase apoprotein gene mutant. Here we have used pB-NiR1 in RFLP analysis to determine whether the mutation carried by STA3999 is linked to the nitrite reductase apoprotein gene locus Nii. An RFLP was identified between the wild-type barley cultivars Tweed (major hybridising band of 11.5 kb) and Golden Promise (major hybridising band of 7.5 kb) when DraI-digested DNA was probed with the insert from the partial barley nitrite reductase cDNA clone, pBNiR1. DraI-digested DNA from the mutant STA3999 also exhibited a major hybridising band of 11.5 kb after hybridisation with the insert from pBNiR1.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗