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PubMedDate not supplied

[Why does the DNA code contain 4 letters?].

The answer to this question is not yet known. There are two ways to express information, i.e., to reduce the number of letters in alphabet (n), which simplifies the decoding machine, but leads to longer informational sequences, or to increase n, which shortens sequences, but complicates the informational machine. The compromise between these two possibilities would be to obtain the minimum of one of summary informational component's parameters. The summary component is the sum of corresponding decoding machine's and the program's parameters. In this work it was demonstrated that DNA four-letter code is optimal, for it allows the minimal volume of summary cell informational contents. But it is so only for the most simple DNA. Our calculations may indirectly show that such DNA (and not more complicated) was the object of "projecting" at one of the biological evolution's early stages.

Amino Acid Sequence↗
PubMed1994

[Gastric leiomyosarcoma. Three clinical cases in emergency].

The authors describe three cases of gastric leiomyosarcoma that required surgical treatment in emergency. Myogenic gastric tumors are extremely rare (1-3% of primitive gastric neoplasias) and little is known about their biological evolution, even if they seem to have scarce power of spreading and of local invasion. Echoendoscopy appears to be the best screening method for the evaluation of staging and DT (doubling time). In the authors' opinion, when neoplasms have a diameter less than 5 cm, subtotal or total gastrectomies don't offer better results in the follow-up than simple minimal excision of the gastric tumor.

Aged↗
PubMed1994

Cell death by apoptosis.

Apoptosis has been the focus of considerable attention in recent years. Apoptosis/programmed cell death, is a morphologically distinct process of cell death in which cells die in a controlled manner, in response to specific stimuli, following an intrinsic programme. Apoptosis is a greek work which means "falling off", as of leaves from trees. So occurs in plants suggesting that apoptosis originated very early in biological evolution. This wide spread active process of self destruction is seen in a wide variety of tissues, and is an essential feature in both development and maintenance of multicellular animals. It is ascribed roles in the process of embryogenesis, differentiation, metamorphosis, neural development, epithelial turnover, aging, regulation of cell population of the immune system and tumor regression.

Apoptosis↗
PubMed1976

Selective advantages of various bacterial carbohydrate transport mechanisms.

At least four strategies have been developed by bacteria for capturing carbohydrates. They are typified by the transport mechanisms for glycerol, glucose, lactose, and galactose in Escherichia coli. Glycerol enters the cell by facilitated diffusion catalyzed by specific membrane protein. Once inside the cell, the substrate is trapped by phosphorylation mediated by an adenosine triphosphate (ATP)-dependent kinase. glucose is phosphorylated in transit by a membrane-associated phosphoenolpyruvate phosphotransferase system (PTS). A specific component of this complex serves also for signal recognition to chemotaxis. Lactose is concentrated chemically unaltered by beta-galactoside permease driven by a proton motive force. Galactose is also pumped into the cell, but the process is energized by ATP or its equivalent. In addition, there is a periplasmic galactose-binding protein essential for both transport and chemotactic response. The relative functional merits of each kind of transport mechanism are discussed. Although many bacterial species possess both the concentrative mechanism and the PTS, some employ the former and others the latter for beta-galactoside utilization. The postulate that the PTS is more avid in scavenging while the concentrative permease system permits a broader range of substrate exploitation is supported by the growth responses of 12 bacterial strains to several beta-galactosides.

Bacteria↗
PubMedDate not supplied

[Thyroglobulin].

Explore the source record for details and available documents.

Biological Evolution↗
PubMedDate not supplied

[Gastric leiomyoblastoma. Two case reports].

Two cases of gastric leiomyoblastoma (one of which of exceptional size, measuring more than 40 cm) observed respectively in 1992 at the Surgery Division of USSL 45 at Asola (MN) and in 1990 at the Second Surgery Division of USSL 47 in Mantova are reported. In the first case anaemia revealed the tumor whereas in the second case the patient suffering from a pain in the abdomen was admitted to hospital. These two tumors raise interest for their rarity and for their uncertain biological evolution. They generally develop very slowly and tend to remain intramural. The most frequently attacked seats are the antum-pyloric region and the stomach body. The main symptoms are epigastric pain, nausea, vomiting, weight loss, sideropenic anaemia, epigastric palpable mass. The diagnostic iter includes radiologic examination (digestive tube X-ray, echography, TAC, arteriography), gastroscopy and laparoscopy. In most cases surgical resection is not completely destroying, except for those cases in which the tumor measures more than 5 cm and total or subtotal gastrectomy is performed.

Aged↗
PubMed1996

Molecular characterization of the t(2;5) (p23; q35) translocation in anaplastic large cell lymphoma (Ki-1) and Hodgkin's disease.

The precise cellular origin and the pathogenetic mechanism(s) leading to the neoplastic transformation of anaplastic large cell lymphoma (ALCL) and the Reed-Sternberg cell of Hodgkin's disease (HD) remains largely uncertain. Classical cytogenetic analysis has shown a unique translocation involving bands 2p23 and 5q35 bands in a variable number of ALCLs. It has been recently shown that the nucleophosmin/B23 (NPM) gene (5q35) and a novel anaplastic lymphoma kinase (ALK; 2p23) are the fused genes of t(2;5). To investigate the presence and the precise frequency of NPM-ALK gene products among ALCL and HD cases, a large and well-characterized panel of ALCL (n = 49) and HD (n = 72) cases was studied using multiple strategies including reverse transcriptase-polymerase chain reaction (RT-PCR), Southern blot analysis, and immunohistochemistry. Overall, 6 (3 T and 3 null) of 49 ALCL and 3 (2 nodular sclerosis and 1 mixed cellularity) of 72 HD showed the presence of NPM-ALK transcripts by RT-PCR. NPM-ALK gene rearrangements were detected in all RT-PCR, NPM-ALK-positive ALCL by Southern blot analysis. Furthermore, in all the available cases we were able to show the presence of ALK-related protein using a specific polyclonal antiserum recognizing the cytoplasmic domain of ALK by immunohistochemistry. Our data show that NPM-ALK gene transcripts are identified in a subpopulation of ALCL, almost exclusively in T or null cell in origin, and in rare cases of HD. These findings show that some HD may be closely related to ALCL, giving us new insights on the pathogenesis and possibly biologic evolution of HD.

Anaplastic Lymphoma Kinase↗
PubMed1995

[Cholestatic hepatitis and amoxicillin-clavulanic acid combination. Personnel case report and literature review].

The association amoxicillin-clavulanic acid is a widely used medication. Only about 15 cases of cholestatic hepatitis were reported in Belgium between 1990 and 1993; about 100 cases have been reported to the pharmaceutical company. This effect is severe but reversible. The injury is probably idiosyncratic or immunologically based. Age, sex and treatment duration are as many agents of risk. The diagnosis is undertaken on basis of clinical examination, chronological study, biological evolution and histology.

Age Factors↗
PubMed1996

Interspecies cross-reactivity of a monoclonal antibody directed against wheat chloroplast fructose-1,6-bisphosphatase.

The primary structure of several chloroplast fructose-1,6-bisphosphatase (CFBPase) was deduced from DNA sequences, but only spinach, pea and rapeseed enzymes have been characterized structurally. We analyzed whether CFBPases from different phylogenetic origin contain a common epitope. To this end a DNA fragment of 1200 base pairs encoding 338 amino acid residues of wheat CFBPase (38 kDa) was cloned in the expression plasmid pGEX-1 in frame with the gene coding for glutathione S-transferase (GT) of Schistosoma japonicun (26.5 kDa). Upon transformation of Escherichia coli and induction with isopropyl-beta-D-thiogalactopyranoside, centrifugation of the lysate partitioned 10% of the fusion protein in the supernatant fraction and the remaining 90% in the precipitate. The expected 65 kDa protein was purified from both the soluble and the particulate fraction by affinity chromatography on columns of glutathione-agarose. This fusion protein was successfully used to produce a monoclonal antibody that specifically recognized the CFBPase region of the fusion protein but not the GT moiety. Moreover, the monoclonal antibody immunoreacted not only with polypeptides (ca. 40 kDa) present in leaf crude extracts of other varieties of wheat (Triticum spelta, T. aestivum and T. durum), but also with homogeneous preparations of the spinach (Spinacia oleracea) and rapeseed (Brassica napus) enzymes. Thus, the cross reaction of this monoclonal antibody with counterparts from different plant species indicates the persistency of a common epitope through biological evolution.

Amino Acid Sequence↗