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141.
A numerical algorithm has been developed for the estimation of the mechanical parameters of the human respiratory system. In order to estimate the pulmonary resistance and the dynamic pulmonary elastance, the transpulmonary pressure and the airflow at the mouth or nose are expanded in Chebyshev series. The nonlinear mathematical lung model and a set of measurements for airflow and pressure are then handled by the numerical technique. The lung model includes a component to account for turbulent flow in the larynx and trachea. This contribution presents an alternative method for lung parameter estimation and differs from most existing methods in that it does not need measurements for the tidal volume. It therefore eliminates the use of a body plethysmograph. The method may also find potential application to various other parameter identification problems. 相似文献
142.
The isolation of eucannabinolide and three new sesquiterpene lactones from Schkuhria anthemoidea is reported. The structures and stereochemistries of the new compounds were established by chemical and spectroscopic means. The structure of santhemoidin B was confirmed by X-ray crystallography. 相似文献
143.
JoséL. Jorcano Michael Rieger Juergen K. Franz Dorothea L. Schiller Roland Moll Werner W. Franke 《Journal of molecular biology》1984,179(2):257-281
Cytoskeletal filaments of the α-keratin type (cytokeratins) are a characteristic of epithelial cells. In diverse mammals (man, cow and rodents) these cytokeratins consist of a family of approximately 20 polypeptides, which may be divided into the more acidic (I) and the more basic (II) subfamilies. These two subfamilies show only limited amino acid sequence homology. In contrast, nucleic acid hybridization experiments and peptide maps have been interpreted to show that polypeptides of the same subfamily share extended sequence homology.We compare two polypeptides of the acidic cytokeratin subfamily, VIb (Mr 54,000) and VII (Mr 50,000), which are co-expressed in large amounts in bovine epidermal keratinocytes. These two epidermal keratins can be distinguished by specific antibodies and show different patterns of expression among several bovine tissues and cultured cells. In addition, they differ in the stability of their complexes with basic keratin polypeptides and in their tryptic peptide maps. The amino acid sequences deduced from the nucleotide sequences of complementary DNA clones containing the 3′ ends of the messenger RNAs for these keratins are compared with each other and with available amino acid sequences of human, murine and amphibian epidermal keratins. Bovine keratins VIb and VII share considerable sequence homology in the α-helical portion (68% residues identical) but lack significant homology in the extrahelical portion. Bovine keratin VIb shows, in its α-helical region, a pronounced sequence homology (88% identity) to the murine epidermal keratin of Mr 59,000. In addition, the non-helical carboxy-terminal regions of both proteins are glycinerich and contain a canonic sequence GGGSGYGG, which may be repeated several times. Moreover, their mRNAs present a highly conserved stretch of 236 nucleotides containing, in the murine sequence, the end of the coding and all of the non-coding region (81% identical nucleotides). Bovine keratin VII is considerably different from the murine Mr 59,000 keratin but is almost identical to the human cytokeratin number 14 of Mr 50,000, both in the α-helical and in the non-α-helical regions of the proteins, and the mRNAs of the human and the bovine keratins also display a high homology in their 3′ non-coding ends.The results show that in the same species keratins of the same subfamily can differ considerably, whereas equivalent keratin polypeptides of different species are readily identified by characteristic sequence homologies in the α-helical and the non-helical regions as well as in the 3′ non-coding portions of their mRNAs. Among the members of the acidic subfamily I of cytokeratin polypeptides that are co-expressed in bovine epidermis, at least two types can be distinguished by their carboxy-terminal sequences. One type is characterized by its abundance of glycine residues, a consensus GGGSGYGG heptapeptide sequence, which may be repeated several times, and an extended stretch of high RNA sequence homology in the 3′ non-coding part. The other type shows a predominance of serine and valine residues, a subterminal GGGSGYGG sequence (which has been maintained in Xenopus, cow and man) and also a high level of homology in the 3′ non-coding part of the mRNA. The data indicate that individual keratin type specificity overrides species diversity, both at the protein and the mRNA level. We discuss the evolutionary conservation and the tissue distribution of these two types of acidic keratin polypeptides as well as their possible biological functions. 相似文献
144.
145.
DQ α and β RFLP reveals the composition of the DQ molecule recognized by T-cell clones 总被引:2,自引:0,他引:2
Sharon Rosenshine Isabella Cascino Adriana Zeevi René J. Duquesnoy Massimo Trucco 《Immunogenetics》1986,23(3):187-196
Pst I RFLP, revealed with DQ
and DQ
probes, was compared with Taq I RFLP using a panel of DR-homozygous cell lines and HLA-typed family members. Taq I patterns, characteristic for each DR-associated DQ and allelic forms, were recognized in the homozygous state and then proven to segregate in the heterozygous members of informative families. The presence of both specific and chains was found to be necessary to form the type of DQ molecule specifically recognized by two alloreactive T-cell clones. Particular and associations also seem to be responsible for some Dw splits of the DRw6-positive cells. Taq I RFLP analysis may be more complex than the Pst I analysis, but is certainly more informative and complete, considering the type of information we were seeking by performing these types of experiments.Abbreviations used in this paper BSA
bovine serum albumin
- GLO
glyoxalase
- kb
kilobase(s)
- LCL
lymphoblastoid cell line
- MHC
major histocompatibility complex
- PBL
peripheral blood lymphocyte
- PLT
primed lymphocyte test
- RFLP
restriction fragment length polymorphism
- SDS
sodium dodecyl sulfate
- SSC
standard sodium citrate
- SSCP
sodium, sodium citrate, sodium phosphate
- TBE
Tris-borate, boric acid, ethylenediaminetetraacetate (EDTA)
- TCGF
T-cell growth factor 相似文献
146.
S. L. Eduardo 《Systematic parasitology》1986,8(1):57-69
Summary Only Stephanopharynx compactus Fischoeder, 1901 is considered valid under the genus Stephanopharynx Fischoeder, 1901 and S. secundus Stunkard, 1929 and S. coilos Dollfus, 1963 are regarded as its synonyms. The species is redescribed and illustrated based on new material and scanning
electron photomicrographs of its tegumental surfaces and the internal surface of its pharyngeal pouch are provided.
Balanorchis anastrophus Fischoeder, 1901, the one and only species of the genus Balanorchis Fischoeder, 1901 is redescribed and illustrated. Photomicrographs of its tegumental surfaces as revealed by scanning electron
microscopy are given.
Additional information on Bilatorchis papillogenitalis Eduardo, 1980 is included.
Part of a thesis approved by the University of London for the award of the Ph.D. degree.
Part of a thesis approved by the University of London for the award of the Ph.D. degree. 相似文献
147.
A galactofuranosyl-containing glycopeptide has been isolated from mycelium ofAscobolus furfuraceus by extraction with water. The glycoconjugate was purified by DEAE-cellulose chromatography followed by gel filtration. A molecular weight of about 20 000 was determined by the latter method using standard dextrans. Neutral sugars accounted for 94.5% of the glycopeptide and were characterized as mannose, galactose, and glucose. Glucosamine was estimated colorimetrically (1.8%). The molar ratio of Man:Gal:Glc:GlcNH2 was 68:32:16:2. A trace amount of total phosphorus (0.2%) was found. The predominant amino acids were threonine and serine. The peptide moiety was labeled with [14C]formaldehyde and the elution of radioactivity was coincident with sugar on gel filtration in the presence of sodium dodecyl sulfate. The peak of radioactivity was retarded on release of galactose by mild acid hydrolysis. These results confirm the sugar-peptide linkage. 相似文献
148.
149.
Dr. Jacques F. G. M. Meis P. Jos M. Rijntjes Jan Peter Verhave Thivi Ponnudurai Michael R. Hollingdale Judith E. Smith Robert E. Sinden Paul H. K. Jap Joseph H. E. T H Meuwissen Sing Hiem Yap 《Cell and tissue research》1986,244(2):345-350
Summary Recent advances in the ability to culture the hepatic forms of mammalian malaria parasites, particularly of the important human pathogen Plasmodium falciparum have provided novel opportunities to study the ultrastrucural organisation of the parasite in its natural host cell the human hepatocyte. In this electron-microscopic and immunofluorescence study we have found the morphology of both parasite and host cell to be well preserved. The exoerythrocytic forms, which may be found at densities of up to 100/cm2, grow at rates comparable to that in vivo in the chimpanzee. In the multiplying 5- and 7-day schizogonic forms the ultrastructural organisation of the parasite bears striking resemblances to other mammalian parasites, e.g., the secretory activity and distribution of the peripheral vacuole system, but also homology with avian parasites, e.g., in nuclear and nucleolar structure and mitochondrial form. The latter homologies support earlier suggestions of the close phylogenetic relationship of P. falciparum with the avian parasites. Evidence is also presented showing the persistence of the cytoskeleton of the invasive sporozoite within the cytoplasm of the ensuing rapidly growing vegetative parasites. 相似文献
150.
Dr. Olivier Kah Pierrette Dubourg Brigitte Onteniente Michel Geffard André Calas 《Cell and tissue research》1986,244(3):577-582
Summary The dopaminergic innervation of the goldfish pituitary gland was studied by immunocytochemistry at the electron-microscope level using highly specific antibodies against dopamine coupled to bovine serum albumin with glutaraldehyde. A satisfactory preservation of the tissue was achieved after immersion in 5% glutaraldehyde in phosphate buffer containing sodium metabisulfite to prevent oxidation of the endogenous dopamine. The immunocyto-chemical procedure was performed on Vibratome sections using the preembedding method. Immunoreactivity was restricted to part of the neurosecretory type-B fibers (diameter of the secretory vesicles lower than 100 nm) in which it was found to occupy the whole cytoplasm. Labeled fibers were observed within the neurohypophysis in the different parts of the gland and in the adenohypophyseal tissue where immunoreactive profiles were detected in close apposition to the different cell types. These data are in agreement with previous results obtained by means of radioautography and further support a role for dopamine in the neuroendocrine regulation of pituitary functions in teleosts. 相似文献