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Biomedical subjects

A Klein

Publications and source records attributed to A Klein.

At least 271 records · Page 15Linked to original sources
PubMed1991

Effect of anticoagulants in vitro on the viability of lymphocytes and content of free fatty acids in plasma.

These authors attempted to test the effect of anticoagulants on lymphocytes viability by reproducing the procedure used for lymphocyte isolation for various immunologic tests in which blood specimens are allowed to stay at room temperature for 2 h before lymphocytes are isolated. Blood was obtained with three different anticoagulants i.e. heparin, citrate, and CPDA (citrate, phosphate, dextrose, and adenine). Plasma was lyophilized and extracted with ethanol. Dried ethanol extracts were suspended in medium (RPMI 1640 + 10% fetal bovine serum) and incubated with a lymphocyte cell line (MOLT-4). After 24 h of incubation the viability of cells was examined. The following death rates of the cells were observed: heparin -63 +/- 4.6% (mean +/- SEM), citrate -27 +/- 6.7%, and CPDA 6.2 +/- 0.6% (P less than 0.0005). A significant correlation was found between these results and changes in the concentrations of free fatty acids in the extracts. These results emphasize the importance of choosing the right anticoagulant when the viability of lymphocytes is obligatory.

Adenine↗
PubMed1991

The current status of faculty staffing and resident training in emergency radiology. Results of a survey.

The results of a survey of United States and Canadian radiology residency programs in hospitals maintaining major emergency departments indicate that (1) radiologic faculty assignment to emergency medicine may include "all faculty," "specific faculty," "specific and other faculty," "general," and "musculoskeletal" faculty; (2) a chief of emergency radiology section is designated in less than 35% of radiology departments providing emergency room services; (3) radiology resident rotation in emergency radiology occurs in less than 2/3 of the surveyed programs; and (4) radiology resident experience in emergency radiology ranges from two to 16 weeks in 40% of these programs, the remainder being "unspecified." The effect of this circumstance upon the emergency department patient care and resident teaching in emergency radiology is discussed and remedial suggestions presented.

Canada↗
PubMed1991

Macronuclear and micronuclear configurations of a gene encoding the protein synthesis elongation factor EF 1 alpha in Stylonychia lemnae.

The micronuclear and macronuclear configurations of a gene encoding the protein synthesis elongation factor EF 1 alpha in the hypotrich ciliate Stylonychia lemnae were compared. The two sequences are generally colinear. The coding sequence of the micronuclear gene is, however, interrupted by a 64 bp insert flanked by a 2 bp direct repeat in a gene region which is moderately conserved among EF 1 alpha genes of different organisms. The insertion site is distinct from known intron positions in eukaryotic EF 1 alpha genes. The insert sequence shows inverted repeats at its ends and thus exhibits typical features of an internal eliminated sequence (IES). Comparison with other such sequences in the related organism Oyxtricha nova shows that the IES falls into a new group of such elements. The macronuclear gene exhibits a strikingly limited codon usage, which cannot be simply explained by the overall base composition of the DNA but probably also relates to the very high copy number of the macronuclear gene and the putative high amount of the gene product.

Amino Acid Sequence↗
PubMed1991

Physical and genetic map of the Methanococcus voltae chromosome.

A physical map of the Methanococcus voltae chromosome was constructed on the basis of restriction mapping and cross-hybridization experiments, employing total and partial digests obtained with rarely cutting restriction enzymes. On the basis of the sum of the fragment sizes of digests with seven enzymes the chromosome length was calculated to be approximately 1900 kb. The derived map is circular. Hybridization of gene probes to mapped restriction fragments has led to a genetic map of genes for structural RNAs as well as proteins, including enzymes involved in the methanogenic pathway.

Archaea↗
PubMed1991

The carbohydrate diversity of human respiratory mucins: a protection of the underlying mucosa?

Human respiratory mucins consist of a family of glycoproteins with different peptides in which glycosylation, the major post-translational phenomenon, is responsible for about 70 to 80% of the weight of these molecules. This glycosylation generates a remarkable diversity of O-glycosidically linked carbohydrate chains, which are expressed as several hundreds of different chains in a single person. These chains, which can vary from one to about 20 sugars, may be neutral, sialylated, or sulfated. They bear multiple epitopes. Some antigenic determinants such as ABO, Leb antigens in secretor individuals, Lea, or X or Y antigens have been identified. There is increasing evidence that, among other functions, this diversity of chains allows many interactions with microorganisms and may be an important factor in maintaining the sterility of the respiratory tree. In certain pathologic situations such as cystic fibrosis, which is associated with colonization by Pseudomonas aeruginosa, the hypothesis of an alteration of this interaction is open.

Carbohydrate Sequence↗
PubMed1991

Behavior management issues for pediatric patients.

Managing pediatric dental patients who have physical or psychological problems can be challenging for the practitioner. Some pediatric behavior management tools and guidelines are presented.

Anesthesia, Dental↗
PubMed1991

Squamous cell carcinoma of the gingiva presenting as an endoperiodontic lesion.

An unusual case of gingival carcinoma, initially presenting as an endoperiodontic lesion without clinical evidence of malignancy, is presented. It is important to consider carcinoma of the gingiva in cases of an endoperiodontic lesion unresponsive to therapy, and to investigate further when bone resorption occurs around one tooth. Submission of all dental tissue removed during oral surgical procedures for pathologic analysis may be beneficial.

Aged↗
PubMed1991

3H-thymidine incorporation method versus colony forming assay in the determination of anchorage-independent cell growth of rat sarcoma (XC) and Morris hepatoma 7777 (MH) cells.

The modification of 3H-thymidine incorporation method of Tanigawa was used to the estimation of anchorage-independent growth of virally and chemically transformed rat cells. The relationship between colony forming assay and 3H-TdR incorporation test was determined, depends on the composition of culture medium and the period of incubation of rat sarcoma (XC) cells with thymidine. The influence of exogenous mitogens (RFG, TGF beta 1 and insulin) and autocrine factor (at different step of purification) on the growth of Morris hepatoma 7777 (MH) cells was estimated by both methods. Regression analysis comparing the results of colony counting and thymidine incorporation revealed good correlation between the two methods. The modification can be used the determination of growth stimulating or growth inhibiting activity and in multistep purification procedure of autocrine growth factors.

Animals↗
PubMed1991

Structural measures as predictors of injury basketball players.

The purpose of this study was to investigate the relationship between structure and injury in basketball players, with the goal of developing equations to predict injury. We examined 45 subjects who were participating in a community center basketball league. Each subject was measured prior to the season for bilateral weight, quadricep girth, calf girth, Q-angle of the knee, dorsiflexion of the ankle, forefoot varus, rearfoot valgus, and true and apparent leg length. All lower extremity injuries causing a game to be missed were recorded during the 16-game season. Average values for bilateral weight, quadricep girth, Q-angle, rearfoot valgus, and leg length measures for the injured players were all larger than the average for the non-injured players by at least one standard deviation. A logistic regression equation using three of the variables correctly predicted the injury status of 91% of the players. The three-variable equation was then used prospectively to predict injury status for members of a small college basketball team. Only one player missed a game due to injury, and the equation identified that player as the most likely to be injured. This study demonstrates a strong relationship between structural measures and lower extremity injury in basketball players.

Ankle Injuries↗
PubMed1990

Transforming growth factor-beta 1 stimulates proliferation of Morris hepatoma cells in serum-free soft agar culture system supplemented with EGF and insulin.

The anchorage-independent growth of Morris hepatoma 7777 (MH) cells in serum-free medium was examined. The influence of insulin, epidermal growth factor and transforming growth factor beta 1 (TGF-beta 1) on [3H]thymidine incorporation and colony formation of the investigated cells was described. Contrary to normal rat hepatocytes TGF-beta 1 plus EGF and insulin were found to stimulate MH cells proliferation in presented conditions. A simple, chemically-defined culture system suitable for research on mitogenic peptides was proposed.

Animals↗
PubMed1990

Serum changes the response of cultured Morris hepatoma 7777 cells to autocrine growth factors.

The addition of calf serum to culture medium alters the biological response of Morris hepatoma 7777 (MH) cells to autocrine growth factors isolated from conditioned medium of the investigated cells. Acetic acid (AA) extract obtained from conditioned medium of MH cells showed a change in anchorage-independent growth-regulatory activity from stimulation (serum-free) to inhibition (10% calf serum). Two protein fractions of apparent molecular weight 15 and 7.5 kDa isolated from AA-extract by Bio-Gel P-60 filtration also changed their growth-regulatory activity after supplementation of culture medium with calf serum. The contradictory effect of autocrine regulators estimated in soft agar using the 3H-thymidine (3H-TdR) incorporation test and colony formation assay gave generally comparable results, except in the case of the 15-kDa fraction. The most active 7.5-kDa fraction stimulated 3H-TdR incorporation and colony formation in serum-free medium up to about 300 and 500% respectively, while in the presence of 10% calf serum inhibition of about 20 and 50% has been observed. Our results suggest that the fraction contains an autocrine growth factor(s), whose activity is inverted in the presence of serum.

Animals↗
PubMed1990

The mouse ribosomal protein L7 gene. Its primary structure and functional analysis of the promoter region.

The expressed gene coding for mouse ribosomal protein L7 (rpL7) was structurally and functionally characterized. It consists of seven exons, spans 3107 base pairs, and its coding sequence initiates within exon 1. The primary structure of mouse rpL7 (270 amino acids), as inferred from the nucleotide sequence of the exons of the gene, and from the cDNA, is 12 residues longer than the rat counterpart. The rpL7 gene shares common structural features with most other mammalian ribosomal protein genes analyzed thus far. These include the lack of a canonical TATA box and a major transcription initiation site at a cytidine residue embedded in a stretch of 14 pyrimidines, flanked by C + G-rich regions. Transient expression assays revealed that the promoter region of rpL7 gene bears several regulatory elements, both upstream to the capsite and within the transcribed portion of the gene. One internal regulatory element was assigned to the first intron and a second one to a 20-base pair region spanning the first exon-intron junction. The activity of a deletion mutant of rpL32 gene, lacking its internal elements can be rescued by insertion, in the sense orientation, of the corresponding elements from the rpL7 gene. The unique spatial organization of the regulatory elements in rpL7 gene, as well as in other murine ribosomal protein genes examined thus far, might indicate that this common architecture is involved in the mechanism coordinating their expression.

Amino Acid Sequence↗
PubMed1990

Specific transcription of cloned Methanobacterium thermoautotrophicum transcription units by homologous RNA polymerase in vitro.

Specific in vitro transcription by partially purified RNA polymerase from Methanobacterium thermoautotrophicum of DNA sequences cloned in between the promoter and terminator regions of the methyl CoM reductase transcription unit of the same organism is described. The 5'-terminus of the product has been mapped. Deletion analyses of the promoter region show the limits of the sequences essential for the promoter function.

Base Sequence↗