Dissection of the enhancer activity of beta-globin 5' DNase I-hypersensitive site 2 in transgenic mice

The beta-globin locus control region (LCR) consists of four erythroid-specific DNase I-hypersensitive sites, which are necessary for high-level expression of the beta-like globin genes in erythroid tissues. One of these sites, designated 5'HS-2, functions as an erythroid-specific enhancer element in transfection and transgenic mouse experiments. Recent transfection experiments and studies of DNA-protein interactions have localized the 5'HS-2 enhancer to 18 nucleotides that contain a binding site for both the erythroid-specific factor nuclear factor erythroid 2 (NFE-2) and for activator protein 1 (AP-1). To define the sequences necessary for in vivo enhancer activity, several deletion mutants of 5'HS-2 were linked to the human beta-globin gene and their activity was tested in transgenic mice. Three upstream fragments of 5'HS-2 [341, 374, and 412 base pairs (bp)], each of which contained the NFE-2/AP-1 sequences, resulted in beta-globin expression at levels equivalent to or higher than those observed with the entire 732-bp 5'HS-2 fragment. In contrast, a 358-bp downstream portion of 5'HS-2, which lacked the NFE-2/AP-1 sequences, resulted in beta-globin expression at the low levels seen with the beta-globin gene alone. Removal of the NFE-2/AP-1 sequences by a 67-bp internal deletion resulted in similar low levels of beta-globin expression. A 100-bp 5' fragment that contained the NFE-2/AP-1 sequences resulted in beta-globin expression that was higher than the beta-globin gene alone but lower than the entire 5'HS-2 fragment or the three larger upstream fragments. These studies demonstrate that the NFE-2/AP-1 sequences are essential for enhancer activity of 5'HS-2 but that other sequences are required for full activity in vivo.

Inhibition of benzo[a]pyrene-induced mouse forestomach neoplasia by a principal flavor component of Japanese-style fermented soy sauce

A refined diet supplemented with Japanese-style fermented soy sauce (shoyu) inhibits benzo[a]pyrene-induced forestomach neoplasia in mice (Cancer Res., 51:2940-2942, 1991). In the present study, soy sauce was extracted with ethyl acetate. The soluble fraction contained flavor/aroma compounds and antioxidants, whereas amino-carbonyl compounds that impart color were concentrated in the ethyl acetate insoluble fraction. Both fractions inhibited benzo[a]pyrene-induced forestomach neoplasia in a protocol in which the test material was fed following exposure to the carcinogen. A principal flavor/aroma component of soy sauce, 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone, was fed to mice following benzo[a]pyrene administration and found to inhibit the subsequent development of forestomach neoplasia. 4-Hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone was effective when fed at 4 mg/kg body weight/day, indicating that it is a potent anticarcinogen.

[A study on spontaneous closure of ventricular septal defect using 2 dimensional echocardiography]

The results of 2 dimensional echocardiographic (2DE) observation in 73 patients with clinically diagnosed spontaneous closure of ventricular septal defect (VSD) were reported. 2DE showed that aneurysm of the membranous septum formed at the defect portion in 54 patients (74%), tricuspid valve leaflet tissue adhered to the defect portion in 2 patients, coarse appearance of the membranous septum in 8 patients, no defect in 9 patients. There was no shunt flow detected in 59 patients, trivial shunt flow in 14 patients on Doppler echocardiography. All VSD were of the membranous and perimembranous inlet type. The results of this study suggested spontaneous closure of membranous VSD was related to the aneurysmal formation of the membranous septum and adhesion of tricuspid valve tissue.

Mutation of the high affinity calcium binding sites in cardiac troponin C

Fast skeletal and cardiac troponin C (TnC) contain two high affinity Ca2+/Mg2+ binding sites within the C-terminal domain that are thought to be important for association of TnC with the troponin complex of the thin filament. To test directly the function of these high affinity sites in cardiac TnC they were systematically altered by mutagenesis to generate proteins with a single inactive site III or IV (CBM-III and CBM-IV, respectively), or with both sites III and IV inactive (CBM-III-IV). Equilibrium dialysis indicated that the mutated sites did not bind Ca2+ at pCa 4. Both CBM-III and CBM-IV were similar to the wild type protein in their ability to regulate Ca(2+)-dependent contraction in slow skeletal muscle fibers, and Ca(2+)-dependent ATPase activity in fast skeletal and cardiac muscle myofibrils. The mutant CBM-III-IV is capable of regulating contraction in permeabilized slow muscle fibers but only if the fibers are maintained in a contraction solution containing a high concentration of the mutant protein. CBM-III-IV also regulates myofibril ATPase activity in fast skeletal and cardiac myofibrils but only at concentrations 10-100-fold greater than the normal protein. The pCa50 and Hill coefficient values for Ca(2+)-dependent activation of fast skeletal muscle myofibril ATPase activity by the normal protein and all three mutants are essentially the same. Competition between active and inactive forms of cardiac and slow TnC in a functional assay demonstrates that mutation of both sites III and IV greatly reduces the affinity of cardiac and slow TnC for its functionally relevant binding site in the myofibrils. The data indicate that although neither high affinity site is absolutely essential for regulation of muscle contraction in vitro, at least one active C-terminal site is required for tight association of cardiac troponin C with myofibrils. This requirement can be satisfied by either site III or IV.

Cloning, mapping, and sequencing of 3' and its flanking region of bovine alpha-s1 casein gene

A positive clone was isolated from a bovine genomic library in EMBL3 with the probe of alpha-s1 casein gene cDNA. The results from both restriction endonuclease digestion and Southern hybridization probed with the upstream and downstream fragments from the termination codon of bovine alpha-s1 casein gene cDNA suggested that the clone contained 3.5 kb downstream and 10.2 kb upstream fragments from the termination codon of alpha-s1 casein gene. Some divergences in restriction endonucleases sites, a few deletions, and many point mutations were found in introns and exons when compared with those which were published.

[Hypolipodemic action of zhikeqing]

Zhikeqing is a compound prescription of Chinese herbs. It has been proved shown to possess an obvious effect on lipid and lipoprotein cholesterol contents in the serum of hyperlipidemic mice or rats.

Alignment, classification, and three-dimensional reconstruction of single particles embedded in ice

Cryo-electron microscopy of single biological particles poses new challenges to digital image processing due to the low signal-to-noise ratio of the data. New tools have been devised to deal with important aspects of 3-D reconstruction following the random-conical data collection scheme: (a) a new shift-invariant function has been derived, which promises to facilitate alignment and classification of single particle projections; (b) a new method of orientation search is proposed, which makes it possible to relate random-conical data sets to one another prior to reconstruction; and (c) the foundation is laid for a 3-D variance estimation which utilizes the oversampling of 3-D angular space by projections in the random-conical reconstruction scheme.

The role of perceived barriers in the use of a comprehensive prenatal care program

This study focused on the use of community-based networks for prenatal care by black women in three high-risk communities in Chicago. We examined factors associated with use of network affiliated medical providers among 177 women. Sociodemographic factors and health status measures had no effect on network affiliated provider use. However, perceived barriers to care differentiated those who used affiliated providers from those who used alternative sources for care. Out of ten possible barriers, the odds ratios for job demands, travel time to providers and child care were significantly different from one. Implications for program modifications and expansion are discussed.

Conversion of Bacillus subtilis 168 to a subtilin producer by competence transformation

Subtilin is a ribosomally synthesized peptide antibiotic produced by Bacillus subtilis ATCC 6633. B. subtilis 168 was converted to a subtilin producer by competence transformation with chromosomal DNA from B. subtilis ATCC 6633. A chloramphenicol acetyltransferase gene was inserted next to the subtilin structural gene as a selectable marker. The genes that conferred subtilin production were derived from a 40-kb region of the B. subtilis ATCC 6633 chromosome that had flanking homologies to the B. subtilis 168 chromosome. The subtilin produced by the mutant was identical to natural subtilin in its biological activity, chromatographic behavior, amino acid composition, and N-terminal amino acid sequence.

Effects of exogenous auxins on expression of lipoxygenases in cultured soybean embryos

The expression of lipoxygenases (LOXs) is known to be developmentally regulated in soybeans (Glycine max. [L.] Merr.). Hormones have been firmly established as being involved in the growth and developmental processes of a number of plant species. Correlation between the expression of LOXs and the development and germination of soybean embryos suggests that plant hormones may affect the expression of LOXs. The present studies were conducted to investigate the effects of exogenous auxins on the expression of LOX isozymes and LOX activities in cultured cotyledon tissues of immature soybean seeds. The results revealed that at least one of the more acidic nonembryo LOX isozymes was induced by either alpha-naphthaleneacetic acid or indoleacetic acid but not by 2,4-dichlorophenoxyacetic acid after 4 days' exposure. Levels of LOX-1, -2, and -3 proteins and activities were significantly decreased by 2,4-dichlorophenoxyacetic acid 10 days after explanting. S1 analysis showed that embryo LOX messenger RNAs were detectable in the tissues treated with each of the auxins. The reduced levels of the embryo LOX proteins may, therefore, be regulated at the levels of translation, posttranslational modification, or degradation. The more acidic isozymes induced by alpha-naphthaleneacetic acid showed enzymatic activity and shared the same molecular mass and isoelectric point values as the germination-associated LOX isozymes found in hypocotyls and radicles, suggesting that those LOXs are involved in germination competency of soybean embryos.

Mapping the receptor-recognition site of human transforming growth factor-alpha

The receptor-recognition site human transforming growth factor-alpha (TGF alpha), a 50-residue tricyclic peptide with three disulfide bonds, was mapped by a set of 46 peptide analogs consisting of linear, monocyclic, bicyclic, and tricyclic structures representing individual and overlapping subdomains of human TGF alpha. Linear overlapping fragments ranging from 7 to 18 residues and spanning the entire length of TGF alpha as well as monocyclic analogs with one disulfide linkage were found to be inactive in both receptor-binding and mitogenic assays. Bicyclic analogs with two disulfide linkage and representing either the amino or carboxyl two-thirds of TGF alpha showed low activity at 0.1-0.9 mM concentrations. Tricyclic analogs containing all three disulfide linkages but lacking either the amino or carboxyl terminal heptapeptide was, respectively, 3% and 0.1% as active as TGF alpha. These results show that determinants for the receptor binding cannot be represented by a short continuous fragment or a single subdomain, but are located on a discontinuous surface on a folded structure with disulfide restraints. Furthermore, these results when combined with our previous results which shows that the middle subdomain (second disulfide loop) is not involved in the receptor binding suggest that the receptor-binding residues are constituted of three fragments located at the first and third subdomains as well as the external carboxyl peptide.

[Clinical value of the Chengdu classification of non-Hodgkin's lymphomas]

Two hundred forty-nine cases of non-Hodgkin's lymphomas (NHL) were reviewed by using the working classification of NHL (Chengdu, 1985). The results showed that the patients of 249 cases of NHL ranging in age from 5 to 76 years, with the mean age of 42 of the types were separated into three major prognostic groupings as follows: 1. low (41 of 249 cases, small lymphocytic 27 cases, lymphoplasmacytoid 2 cases, follicular cleaved 7 cases, follicular cleaved and noncleaved 5 cases); 2. intermediate (58 of 249 cases, diffuse cleaved 28 cases, diffuse cleaved and noncleaved 27 cases, follicular noncleaved 3 cases); and 3. high grade malignancy (150 of 249 cases, diffuse noncleaved 49 cases, lymphoblastic 41 cases, immunoblastic 13 cases, polymorphic 39 cases, clear cell 2 cases, histiocytic 6 cases). Each group was significantly different from the others (P less than 0.05). The prognosis of patients with angioimmunoblastic lymphadenopathy like T-cell lymphoma (9 of 249 cases) was not more significant (P greater than 0.05) than that of patients with other polymorphic lymphoma (30 of 249 cases). The results showed this Chengdu classification of NHL is good for practice and usage in clinical evaluation and routine surgical pathology.

Localization of 616 human chromosome 3-specific cosmids using a somatic cell hybrid deletion mapping panel

A total of 5700 human chromosome 3-specific cosmid clones was isolated from a series of cosmid libraries constructed from somatic cell hybrids whose only human component was an entire chromosome 3 or a chromosome 3 containing an interstitial deletion removing 50% of long arm sequences. Several unique sequence chromosome 3-specific hybridization probes were isolated from each of 616 of these cosmids. These probes were then used to localize the cosmids by hybridization to a somatic cell hybrid deletion mapping panel capable of resolving chromosome 3 into nine distinct subregions. All 616 of the cosmids were localized to either the long or short arm of chromosome 3 and 63% of the short arm cosmids were more precisely localized. We have identified a total of 87 cosmids that contain fragments that are evolutionarily conserved. Fragments from these cosmids should prove useful in the identification of new chromosome 3-specific genes as well as in comparative mapping studies. The localized cosmids should provide excellent saturation of human chromosome 3 and facilitate the construction of physical and genetic linkage maps to identify various disease loci including Von Hippel Lindau disease and renal and small cell lung carcinoma.

Function of the N-terminal calcium-binding sites in cardiac/slow troponin C assessed in fast skeletal muscle fibers

Fast skeletal troponin C (sTnC) has two low affinity Ca(2+)-binding sites (sites I and II), whereas in cardiac troponin C (cTnC) site I is inactive. By modifying the Ca2+ binding properties of sites I and II in cTnC it was demonstrated that binding of Ca2+ to an activated site I alone is not sufficient for triggering contraction in slow skeletal muscle fibers (Sweeney, H.L., Brito, R. M.M., Rosevear, P.R., and Putkey, J.A. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 9538-9542). However, a similar study using sTnC showed that Ca2+ binding to site I alone could partially activate force production in fast skeletal muscle fibers (Sheng, Z., Strauss, W.L., Francois, J.M., and Potter, J.D. (1990) J. Biol. Chem. 265, 21554-21560). The purpose of the current study was to examine the functional characteristics of modified cTnC derivatives in fast skeletal muscle fibers to assess whether or not either low affinity site can mediate force production when coupled to fast skeletal isoforms of troponin (Tn) I and TnT. Normal cTnC and sTnC were compared with engineered derivatives of cTnC having either both sites I and II active, or only site I active. In contrast to what is seen in slow muscle, binding of Ca2+ to site I alone recovered about 15-20% of the normal calcium-activated force and ATPase activity in skinned fast skeletal muscle fibers and myofibrils, respectively. This is most likely due to structural differences between TnI and/or TnT isoforms that allow for partial recognition and translation of the signal represented by binding Ca2+ to site I of TnC when associated with fast skeletal but not slow skeletal muscle.

[Changes in transmembrane action potentials and monophasic action potentials of phase 3 intraventricular block in rabbits]

The model of phase 3 intraventricular block was produced in 10 rabbits by giving 2.5% solution of potassium chloride intravenously under natural breathing and sinus rhythm. Transmembrane action potentials and monophasic action potentials were recorded respectively. The results showed that RP, APA, Vmax, MAPA and MVmax all decreased and both APD and MAPD shortened at the time of ventricular conduction block, when ventricular conduction was improved by vagal stimulation, RP, APA, Vmax, MAPA and MVmax all increased and both APD and MAPD lengthened. In addition, APD and MAPD measured at the same site in normal conduction, conduction block and conduction improved by vagal stimulation were in consensus.

[Status quo and prospects of oral liquid prepared from Chinese drugs]

This paper reviews the rise of oral liquids and their preparations, control standards, pharmacological research and clinical pharmacy, etc. On the basis of investigation, an overall discussion is given in respect to product variety and sale, pharmaceutical research and development, and social benefit from new products, so as to highlight the merits of Chinese medicinal materials.

[Reconstitution of osteoinductive bone xenograft: bioassay in mice]

How to eliminate the antigenicity of bone xenograft while retaining its osteoinductive activities is an unsolved problem in the orthopaedic field. This paper reports an encouraging approach to the question by the following procedures extracting the bone morphogenetic protein (BMP) from cortical bone; eliminating the antigenicity of cancellous bone by chemical extraction; and reconstituting the graft with the treated cancellous bone serving as a delivery medium for BMP. This composite graft is accepted immunologically, and is also osteoinductive in the heterogenous host. In point of delivery medium of BMP, the cancellous bone xenograft is the best choice due to its abundant sources. Bioassay in mouse showed that the reconstituted graft, including only 0.5 mg BMP, demonstrated a definitive osteoinductive ability. In addition, this paper first furnished the information that the BMP aggregate from chemical extraction as described in the literature is also antigenic in the heterogenous host.