Characterization of structure and diffusion behaviour of Ca-alginate beads prepared with external or internal calcium sources

Ca-alginate beads were prepared with either external or internal calcium sources. The structures of both beads were investigated with the aid of scanning electron microscopy (SEM) and confocal microscopy. It was shown that the beads with internal calcium source had a looser structure and bigger pore size than those with external calcium source. The attempts to interpret the difference were carried out by determining the Ca content within the beads at various times, which indicated that it was the different gelation mechanisms that caused the difference of structures of both beads. Furthermore, it was also found that the diffusion rate of haemoglobin (Hb) within the beads with an internal calcium source was faster than that of the beads with an external one, which was consistent with the observation of their structures.

Microorganisms in a high altitude glacier ice in Tibet

Eighty-one strains of viable microorganisms were recovered from 23 samples collected from Ice Core 3 of Malan Glacier (China, 91 degrees 45.3' E, 35 degrees 48.4' N) drilled at high altitude (5620 m). All the strains were prokaryotes--75 of bacteria (including spore-forming ones) and 6 of actinomycetes. The characteristic genera differ from those of Arctic and Antarctic ice, in which many fungi and algae are widely distributed; this shows an difference of environmental conditions between Tibet and polar regions. The variation in number and species of Bacillus in different ice core layers implied changes of environmental conditions in the past.

[Studies on chemical constituents of Gaultheria leucocarpa var. Yunnanensis (Franch.) T. Z. Hsu & R. C. Fang]

OBJECTIVE

To separate and identify the chemical constituents of the aerial part of Gaultheria leucocarpa var. yunnanensis.

METHOD

The compounds were extracted with solvents, isolated by column chromatography and identified by spectral analysis.

RESULT

Four compounds were identified as n-dotriacontane and its homologous compound(1), ursolic acid(2), vanillic acid(3), and quercitrin(4).

CONCLUSION

The compounds 1, 4 were obtained from the plant for the first time, and 2 and 3 were from above-ground part of the plant for the first time.

[Systemic breeding of the new variety of Biantiao ginseng (Panax ginseng)]

OBJECTIVE

To breed new varieties of Biantiao ginseng for high yield and fine quality.

METHODS

Systemic breeding methods were applied. About 3,000 outstanding Biantiao ginseng roots were selected and planted in breeding field, and self-crossed for four generations. During the course, inferior lines or plants were rejected. Then strain comparison, identification of resistance to black-speck disease, and analysis of active compositions were carried out.

RESULTS

"Biantiao 1" (BT1), the first new variety of Biantiao ginseng, with green stems and thick, long, elegant roots and median resistance to black-speck disease, has been harvested since 20 years. The percentage of Biantiao ginseng roots and yield were 15% and 30% higher than the control's respectively. The content of total ginsenosides and the main monomers was 1.8%-2.5% higher than the control's. The characteristics of overground part and root of BT1 were uniform and stable.

CONCLUSIONS

BT1, a new excellent ginseng variety, has a good potential value to be generalized in ginseng production.

[Effects of growth regulator, full exposure and mist spray on the cutting of Eucommia ulmoides]

OBJECTIVE

To study the effects of growth regulator on the cutting method of Eucommia ulmoides seedlings.

METHODS

Treated with H2O (CK), NAA, 6-BA and NAA + 6-BA for 4 hours, respectively, cuttings of 4-year and 20-year trees were cultured for 45-60 days under the shed or full exposure and mist spray. The growth of the cuttings was observed periodically. The number of the roots, the root length, the callus and the death rate were investigated after harvest.

RESULTS

Compared with the cutting from 4-year-old tree, the cutting from 20-year-old tree developed better. The rate of stroking root in treated group was 14 times as much as CK group. Other agronomic traits such as the number of the roots, the root length, the callus, the number of the leaves and the death rate of the cuttings in treated group were all better than that of the cuttings in CK group. The cultural time in treated group reduced by 15 days than that of CK group.

CONCLUSIONS

The present study shows that both full exposure mist spray and growth regulators have remarkable effects on cuttings of tree with different ages for rooting or forming callus.

Genomic profiling of the response of Candida albicans to itraconazole treatment using a DNA microarray

The application of genome-wide expression profiling to determine how drugs achieve their therapeutic effect has provided the pharmaceutical industry with an exciting new tool for drug mode-of-action studies. We used DNA chip technology to study cellular responses to perturbations of ergosterol biosynthesis caused by the broad-spectrum antifungal agent itraconazole. Simultaneous examination of over 6,600 Candida albicans gene transcript levels, representing the entire genome, upon treatment of cells with 10 microM itraconazole revealed that 296 genes were responsive. For 116 genes transcript levels were decreased at least 2.5-fold, while for 180 transcript levels were similarly increased. A global upregulation of ERG genes in response to azole treatment was observed. ERG11 and ERG5 were found to be upregulated approximately 12-fold. In addition, a significant upregulation was observed for ERG6, ERG1, ERG3, ERG4, ERG10, ERG9, ERG26, ERG25, ERG2, IDII, HMGS, NCP1, and FEN2, all of which are genes known to be involved in ergosterol biosynthesis. The effects of itraconazole on a wide variety of known metabolic processes are discussed. As over 140 proteins with unknown function were responsive to itraconazole, our analysis might provide-in combination with phenotypic data-first hints of their potential function. The present report is the first to describe the application of DNA chip technology to study the response of a major human fungal pathogen to drug treatment.

[Screening of anti-bacteria activity of extracts of Gaultheria leucocarpa var. yunnanensis]

OBJECTIVE

To further develop Gaultheria leucocarpa var. yunnanensis, anti-bacteria constituents in it were screened.

METHOD

The constituents were extracted by chromatographic process. The anti-bacteria test was made with regulatory method of analysis.

RESULT AND CONCLUSION

Anti-bacteria test with extracts of water, acetic ester and n-butanol showed that 3 extracts from 22 samples had anti-Staphylococcus aureus action, and the extracts from root and stem showed the same result. 2 extracts could kill Escherichia coli and Pseudomonas aeruginosa. The lower the concentrate, the less the anti-bacteria action was. These results suggested that not only essential oil but other ingredients from G. leucocarpa var.yunnanensis have anti-bacteria activity. Anti-fungi test of the same extracts didn't indicate remarkable action.

[Studies on resources of ethnomedicine Gaultheria leucocarpa var. yunnanensis]

OBJECTIVE

To study the resources of G. leucocarpa var. yunnanensis for further development of this drug.

METHOD

Field investigating, consulting with relevant experts and looking into available specimens.

RESULTS AND CONCLUSION

G. leucocarpa var. yunnanensis is widely distributed in the southern regions of the Yangtze River. The field investigation suggests that the distribution center is situated in Yunnan province, mainly in Kunming, Chuxiong and Dali counties. The climate in these areas is moderate and moist. G. leucocarpa var. yunnanensis is not a dominant species in this natural environment. In some places, it grows with other species of Gaultheria, such as G. fragrantissima, G. tetramera, G. griffithiana and G. leucocarpa var. cumingiana. It is distributed at altitudes from 400 m to 3,500 m. Accustomed to different sunshine conditions, G. leucocarpa var. yunnanensis prefers stronger sunlight and commonly grows on sunny slopes, seldom in dense forest, propagating itself by roots. As a folk medicine, G. leucocarpa var. yunnanensis is commonly used to treat rheumatic arthritis(RA), dazzling, suppressed menstruation, cold, cough, asthma, strain hematemesis, eczema, ascites, wound, amebic dysentery, acute and chronic prostatitis. It is suggested that further pharmacological and clinical researches of this plant be concentrated on the treatment of RA and relief of aches.

[A study on AFLP fingerprinting of land races of Panax ginseng L]

OBJECTIVE

To obtain more information on DNA fingerprintings of five land races of Chinese ginseng, namely, Damaya (DMY), Changbo (CB), Yuanbangyuanlu (YBYL) and Huangguo (HG).

METHODS

The five land races were detected by amplified restriction fragment polymorphism (AFLP) markers with 11 combined primers (M2, M3, M16, M20, M53, M56, M57, M68, M69, M72, M84 in Mse I).

RESULT AND CONCLUSION

Only 4.6% polymorphic sites was found. It was further verified that only a little diversity existed among the land races. The polymorphic sites of CB were much more than those of the others, which suggests that there are more heterozygotes in CB populations, and it is closer to wild ginseng than the others.

Alternative splicing of the histamine H(3) receptor mRNA at the third cytoplasmic loop is not detectable in humans

Histamine regulates neurotransmitter release in the central and peripheral nervous systems through H(3) presynaptic receptors. cDNAs coding for human, guinea pig and rat histamine H(3) receptors have recently been cloned. Cloning of rat and guinea pig H(3) receptors demonstrated the existence of multiple isoforms displaying deletions in the third cytoplasmic loop coding region. We investigated whether a similar splicing pattern might also occur in the human H(3) gene. Using both RT-PCR and RNase protection assays, we detected H(3) receptor mRNA expression in human brain, testes and a cell line expressing recombinant human H(3) receptor (SK-N-MC/H(3)). In all samples tested by both detection methods, only the long mRNA form was detected. We could not find any evidence that humans express other forms equivalent to that seen in the rat or guinea pig. If the alternative splicing seen in rats and guinea pigs presents itself through pharmacological variation, our current findings then have implication for the use of rats or guinea pigs as model system for the development of therapeutic targeting the human H(3) receptor.

Tbt-1, a new T-box transcription factor induced in activated Th1 and CD8+ T cells

Differentiation of CD4+ T cells into T helper (Th) 1 or Th2 cells requires the cytokines interleukin (IL)-12 and IL-4, respectively. However, transcription factors that regulate expression of Th1 or Th2 cell-specific genes remain largely unclear. In the present study, a new Th1-specific transcription factor, named Tbt-1 (T-box protein expressed in T lymphocytes), was identified. Tbt-1 is a novel member of the T-box family, which is characterized by a conserved T-box DNA-binding domain. Unlike other known T-box proteins that regulate embryo development and organogenesis, Tbt-1 expression is restricted to adult lymphoid organs. Tbt-1 mRNA is only detected in peripheral lymphoid tissues such as spleen, lymph nodes, and blood leukocytes, but not in thymus or bone marrow. Tbt-1 mRNA is not detected in resting T cells but is strongly induced in differentiating Thl cells and CD8+ cytotoxic effector cells. In contrast, Tbt-1 expression was not observed in the entire process of Th2 cell differentiation. In addition, phylogenetic analyses indicate that Tbt-1 co-evolved with adaptive immune responses. Thus, Tbt-1 is the first T-box transcription factor shown to be specific for Th1 cell differentiation.

Cleavage and phosphorylation of XRCC4 protein induced by X-irradiation

We report the p35 and p60 forms of XRCC4 protein, appearing in human leukemia MOLT-4 or U937 cells following X-irradiation or hyperthermia. p35 appeared in conjunction with the cleavage of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and the fragmentation of internucleosomal DNA, and was suppressed by Ac-DEVD-CHO. p35 was also produced in vitro by treating MOLT-4 cell lysate with recombinant caspases, suggesting that p35 was a caspase-cleaved fragment of XRCC4 in apoptotic cell death. p60 was sensitive to treatment with phosphatase or wortmannin and was undetectable in M059J cells deficient in DNA-PKcs. However, p60 was found in ataxia-telangiectasia cells after irradiation. These results indicated p60 as a phosphorylated form of XRCC4, requiring DNA-PKcs but not ataxia-telangiectasia mutated (ATM).

[Development of prefabricated flaps]

OBJECTIVE

To sum up the experimental development and clinical application of prefabricated flap.

METHODS

The reported experimental results and clinical application of prefabricated flap extensively reviewed.

RESULTS

Previous studies had proved that the revascularization of prefabricated flap mainly through anastomoses of implanted vessels and the original vessels of the flap, the implanted vessels slowly formed a new and complete blood vessel network, which could dominate the whole flap, three to four weeks later, the new vessels were mature and the flap could be transferred. Clinically, the superficial temporal vessels, gastroepiploic vessels, circumflex femoral vessels and thoracodorsalis vessels could be harvested for prefabricated flap with satisfactory results.

CONCLUSION

Prefabricated flap provides a new method for the treatment of complicated defects.

Xenotransplantation of microencapsulated bovine chromaffin cells into hemiparkinsonian monkeys

This study examines the effects of xenografts of microencapsulated bovine chromaffin cells (BCCs) on the rotational behavior of hemiparkinsonian monkey recipients. In addition, it determines the content of monoamine neurotransmitters and their major metabolites in the neostriatum in hemiparkinsonian monkeys. The hemiparkinsonian model in monkeys was induced by a unilateral intracarotid injection of methyl-phenyl-tetrahydropyridine (MPTP). Unencapsulated BCCs, BCCs microencapsulated in alginate-polylysine-alginate (ALA) membranes as well as empty microencapsules were grafted into the neostriatum of the hemiparkinsonian monkeys. Following the transplantation the hemiparkinsonian symptoms subsided and the number of rotations induced by apomorphine decreased for up to nine months in the group of recipients grafted with microencapsulated BCCs, while only a temporary improvement (one month) was detected in the recipients of the unencapsulated BCCs. No change was observed in the recipients of empty microencapsules. Dopamine and its metabolites were found considerably depleted in the MPTP-lesioned side versus the unlesioned side of the neostriatum in the hemiparkinsonian monkeys(P<0.05).

[Comparison of ITS sequences between wild ginseng DNA and garden ginseng DNA]

OBJECTIVE

To compare the genetic differences between wild ginseng and garden ginseng (Panax ginseng).

METHOD

The sequences of ITS1 and ITS2 of wild ginsengs were determined on LKB DNA sequencing station through Si-liver Sequence DNA Sequencing System. The sequencies were aligned with DNA SIS software.

RESULTS AND CONCLUSION

The ITS1 and ITS2 of Panax were 220-221 and 222-224 bases in length respectively. In Panax ginsehg, the seqences of ITS1 were very stable, but ITS2 were changeable. The ITS2 sequences of No. 87 and No. 110 of the wild ginseng collected from Fusong Heilongjiang (China) were exactly the same as those of No. U41680(Jun Wen) and No. U41682(Jun Wen) of garden ginseng collected from Heilongjiang Province (China) and Korea respectively, but different from those of No. U41681(Jun Wen) from Hubei Province (China) in three bases (447, 449, 450) The result implies that the cultivated ginsengs may have been introduced from two different populations of the wild ginseng.

[Application of multiple tissue expanders for repair of facial and neck scar]

OBJECTIVE

To repair facial and neck scar using tissue expanding technique.

METHODS

From January 1991 to January 1995, 16 cases with facial and neck scar were treated. Multiple tissue expanders were put under the normal skin of facial and neck area, after being fully expanded, the scars were excised and the expended skin flaps were transplanted to cover the defects. The size and number of tissue expanders were dependent on the location of the scars. Normally, 5 to 6 ml expanding volume was needed to repair 1 cm2 facial and neck defect. The incisions should be chosen along the cleavage lines or in the inconspicuous area, such as the nasolabial fold or submandibular region. The design of flap was different in the face and in the neck. In the face, direct advanced flap was most common used, whereas in the neck, transposition flap was often used. Appropriate tension was needed to achieve smooth and cosmetic effect. It was compared the advantages and disadvantages of several methods for repair of the defect after facial and neck scar excision.

RESULTS

Fifteen cases had no secondary deformity after scar excision. Among them, 1 case showed blood circulation disturbance and cured through dressing change. Ten cases were followed up and showed better color and texture in the flap, and satisfactory appearances.

CONCLUSION

Tissue expanding technique is the best method for the repair of facial and neck scar, whenever there is enough expandable normal skin.

Deposition-related sites K5/K12 in histone H4 are not required for nucleosome deposition in yeast

Histone H4 can be acetylated at N-terminal lysines K5, K8, K12, and K16, but newly synthesized H4 is diacetylated at K5/K12 in diverse organisms. This pattern is widely thought to be important for histone deposition onto replicating DNA. To investigate the importance of K5/K12 we have mutagenized these lysines in yeast and assayed for nucleosome assembly. Assaying was done in the absence of the histone H3 N terminus, which has functions redundant with those of H4 in histone deposition. Nucleosome assembly was assayed by three methods. Because nucleosome depletion may be lethal, we examined cell viability. We also analyzed nucleosome assembly in vivo and in vitro by examining plasmid superhelicity density in whole cells and supercoiling in yeast cell extracts. All three approaches demonstrate that mutagenizing K5 and K12 together does not prevent cell growth and histone deposition in vivo or in vitro. Therefore, K5/K12 cannot be required for nucleosome assembly in yeast. It is only when the first three sites of acetylation-K5, K8, and K12-are mutagenized simultaneously that lethality occurs and assembly is most strongly decreased both in vivo and in vitro. These data argue for the redundancy of sites K5, K8, and K12 in the deposition of yeast histone H4.

[The expression of Quox-1 gene homologous sequence in the development of early human embryos]

By using the b2 fragment of Quox-1 gene as probe, we have confirmed that the Quox-1 gene homologous sequence exists in the human genome according to the results of Southern blot. Studies on the expression of Quox-1 homologous sequence in early human embryos from 26 to 37 days by means of immunohistochemistry technigue with Quox-1 protein antibodies showed the spatiotemporal expression patterns: in 26 days embryo Quox-1 homologous sequence was expressed in many places including neural tube, but 30 days later, tits expression sites were limited to notochord, digestive epithelium, myotome, cardiac muscle cell and periderm. The functions in control and regulation of Quox-1 gene homologous sequence during the early development of human embryo were discussed.

[Venous protection of acute leukemia treatment with amsacrine]

Amsacrine (AMSA) was a high effective medicine of acute leukemia treatment. But it could lead to severe phlebitis with venous drip. 44 patients were treated 71 courses with AMSA. After we used fasting venous drip and diluting high concentration AMSA, occurrence of phlebitis remarkably decreased and patients of phlebitis could be cured with early comprehensive nursing.

A search for proteins that interact genetically with histone H3 and H4 amino termini uncovers novel regulators of the Swe1 kinase in Saccharomyces cerevisiae

In a genetic screen for second-site mutations that are lethal in combination with a deletion of the amino terminus of histone H3, we have uncovered three new gene products that regulate the Saccharomyces cerevisiae Swe1 kinase. The Swe1 protein kinase phosphorylates tyrosine residue 19 of Cdc28 and inhibits its activity. One histone synthetic-lethal gene, HSL1, encodes a putative protein kinase that has high sequence and functional homology to fission yeast cdr1/nim1, an inhibitory kinase of wee1. Another gene, HSL7, is a novel negative regulator of Swe1 function. Sequences similar to Hsl7 exist in Caenorhabditis elegans and humans. In addition, we have isolated a dosage-dependent suppressor, OSS1, of hsl1 and hsl7. OSS1 is important for the transcriptional repression of SWE1 and CLN2 in G2. Mutations in HSL1 and HSL7 therefore cause hyperactivity of the Swe1 kinase, which in turn decreases mitotic Cdc28 kinase activity. Moreover, HSL5 is identical to CDC28, further suggesting that it is the decreased Cdc28 kinase activity in these hsl mutants that causes lethality in the histone mutant background. Because neither HSL1 nor HSL7 is essential in yeast, and histone transcription is unaffected by the hsl5/cdc28 mutation, it is unlikely that synthetic lethality results from reduced transcription of HSL1 and HSL7 caused by histone mutations, or from reduced histone transcription when Cdc28 kinase activity is compromised. We suggest that these cell cycle regulators function in a pathway upstream of both histones H3 and H4, thereby modulating histone function in the cell cycle.

Putative mechanism for guinea pig ileum contraction by N-formyl peptides. A comparative study of N-formyl and N-acetyl peptides with the N-terminal sequence of the calpain small subunit

N-formyl and N-acetyl peptides with the N-terminal sequence of the calpain small subunit were prepared and their spasmogenic activity was examined using guinea pig ileum preparations. Sections of ileum were found to contract in the presence of all N-formyl peptides used (tri- to nonapeptides and tridecapeptide) but failed to contract with N-acetyl peptides, although both N-formyl and N-acetyl peptides have chemotactic activity, indicating that spasmogenic activity and chemotactic activity involve different mechanisms. A formyl peptide antagonist, Boc-Phe-Leu-Phe-Leu-Phe, suppressed contraction by formyl peptides whereas a histamine antagonist, diphenhydramine, suppressed contraction by formyl peptides as well as by histamine. In addition, formyl peptide-induced contractions were noted after an approximately 20-sec time lag, and their profiles were bell-shaped and roughly symmetrical. On the other hand, histamine- and acetylcholine-induced contractions exhibited a much shorter time lag. These data led us to conclude that contraction induced by formyl peptides may not occur as a direct response but may be due to the histamine released from mast cells present in the tissues of the small intestine.

Neutrophil chemotactic N-acetyl peptides from the calpain small subunit are also chemotactic for immunocytes

N-terminal peptides from the calpain small subunit were shown to have dose-dependent chemotactic activity toward several types of leukemia cells: T cell, B cell, monocyte and granulocyte/monocyte line leukemia cells. In order to prove that chemotaxis is mediated via receptors, a fluorescein-labeled probe was prepared from one of the N-terminal peptides and its interaction with peripheral leukocytes was estimated by means of flow cytometry, resulting in staining not only of neutrophils but also of most of the monocytes and more than half of the T and B lymphocytes. The results indicate that calpain-derived N-terminal peptides may be involved in defense mechanisms, inducing chemotaxis of immunocytes as well as that of neutrophils.

Neutrophil responses induced by formyl and acetyl peptides with the N-terminal sequence of the calpain small subunit

A series of formylated and acetylated peptides with the amino terminal sequence of the small subunit of human calpains were prepared and their neutrophil activating potency was examined. Formyl peptides showed dose-dependent superoxide generation and elastase/myeloperoxidase releasing activity in addition to chemotactic activity whereas acetyl peptides showed only chemotactic activity and neither superoxide generation nor degranulation activity was detected. These results imply that acetyl peptides from the calpain small subunit might be moderate neutrophil chemotactic factors which do not produce bacteriocidal and cytotoxic effects.

Nutritional regulation of nucleosomal structure at the chicken malic enzyme promoter in liver

Transcription of the chicken malic enzyme gene in the liver is stimulated by feeding and inhibited by starvation. Concomitant with the increase in transcription caused by refeeding, chromatin structure around the transcription start site of the malic enzyme gene is modified in the liver. Digestion of chromatin in isolated nuclei with DNase I revealed four feeding-induced DNase I hypersensitive sites (-220, -170, -130 and -70 bp) near the malic enzyme promoter. Similarly, digestion of chromatin with restriction endonucleases detected enhanced cleavage within this region when birds were refed. Micrococcal nuclease detected the presence of nucleosomes over this region in the starved state, but not in the fed state. After food was withdrawn from fed birds, nucleosomes were reformed in this region within 6 h. The speed and magnitude of the changes in nucleosomal structure in this region suggest that they did not require DNA replication.

A differentiation stage-specific factor interacts with mouse carbonic anhydrase form I gene and a conserved sequence in mammalian beta-globin genes

We have identified in mouse erythroleukemic (MEL) cells a novel factor which binds to the 3' flanking region of beta-globin genes. Upon induction, this DNA binding factor disappears as beta-globin gene transcription increases. The factor protects 20-30 base pairs (bp) of a sequence which is tightly conserved in beta-globin genes including chicken, human, mouse and rabbit. A very similar sequence binds the factor in the mouse carbonic anhydrase form I gene, whose transcription diminishes upon induction of MEL cells. The factor, or a closely related form, is detected in nonerythroid cells and binding sites have been detected in other genes, including c-myb and immunoglobulin heavy chain-enhancer. We suggest that this factor could play a role in determining the timing of gene expression in several differentiating cell types.

Triiodothyronine stimulates and cyclic AMP inhibits transcription of the gene for malic enzyme in chick embryo hepatocytes in culture

In chick embryo hepatocytes in culture, insulin and triiodothyronine (T3) increase malic enzyme activity and the abundance of malic enzyme mRNA by at least 50-fold, and glucagon or cAMP blocks this effect. Steps regulated by these hormones were defined by measuring transcriptional activity with the nuclear run-on assay and multiple fragments of the malic enzyme gene as probes. T3 alone caused a significant increase in transcription within 1 h, with a maximal increase of 30-40-fold occurring by 24 h. When T3 was added with insulin, 80% of the maximum rate was reached in 1 h. Insulin alone had no effect on transcription of the malic enzyme gene; it amplified the response to T3 in the first few hours after adding T3 but did not alter T3's maximal effect. Cyclic AMP for 1 h completely inhibited the increase in transcription caused by T3. The size and speed of the responses of the malic enzyme gene to T3 and cAMP suggest regulation of transcription initiation. T3-stimulated transcription of the malic enzyme gene did not require ongoing protein synthesis despite the fact that inhibitors of protein synthesis inhibited the T3-stimulated accumulation of its mRNA. T3 may directly activate transcription of this gene via its receptor. The pattern of DNase I hypersensitivity of the malic enzyme gene in chick embryo hepatocytes was the same as that in fed chick liver. Insulin, T3, and cAMP had no effect on that pattern. In chick embryo hepatocytes in culture, factors involved in regulation of transcription by insulin, T3, and cAMP may be bound to DNA independently of hormonal treatment.

Nutritional regulation and tissue-specific expression of the malic enzyme gene in the chicken. Transcriptional control and chromatin structure

Refeeding starved chicks causes a 25- to 50-fold increase in the level of malic enzyme mRNA in liver. To define the regulated steps, we measured transcriptional activity of the malic enzyme gene using the nuclear run-on assay and a variety of DNA probes specific to the malic enzyme gene. Refeeding starved chicks stimulated transcription of the malic enzyme gene in liver by 40- to 50-fold. An increased transcription rate was detectable at 1.5 h, was maximal at 3 h, and remained high at 24 h of refeeding. The level of nuclear precursor RNA for malic enzyme assessed by hybridization with intron-specific probes was high in liver of refed birds, and barely detectable in that of starved birds. These results indicate that nutritional regulation of the level of malic enzyme mRNA is transcriptional. Low levels of malic enzyme mRNA in brain, kidney, and heart correlated well with low rates of transcription of the malic enzyme gene in these tissues. In contrast to liver, neither the rate of transcription nor the steady-state level of malic enzyme mRNA was affected by refeeding starved birds. A series of DNase I-hypersensitive sites were located within 4000 base pairs upstream of the transcription start site of the malic enzyme gene in liver. The DNase I-hypersensitive region extending from the start of transcription to 400 base pairs upstream was much more pronounced in the refed state than in the starved state. This change in DNase I hypersensitivity followed the same time course as increased transcription of the malic enzyme gene. This DNase I-hypersensitive region also was present at low intensity in kidney and heart independently of nutritional state. The three constitutive DNase I-hypersensitive sites further upstream were present in liver but not in kidney or heart.

Neutrophil chemotactic activity of N-terminal peptides from the calpain small subunit

On the basis of previous findings that N-acetyl nonapeptide from the human calpain I large subunit has chemotactic activity for neutrophils, a series of peptides with the N-terminal sequence of the calpain small subunit were synthesized and their chemotactic activity was examined. Potent activity was found in N-acetyl tetra, hepta, octa, nona and a larger peptide of 13 residues, although N-acetyl tripeptide showed only weak activity and N-acetyl penta and hexa peptides showed almost no activity. Since the small subunit is identical in calpains I and II, the results indicate that both calpains could be precursor proteins of chemotactic factors for neutrophils.

[Plasma level of cyclic nucleotides in patients with congestive heart failure and their clinical significance]

Plasma concentrations of cyclic nucleotides were determined by radioimmunoassay in 196 cardiac patients. The results showed that plasma concentrations of cyclic AMP and cyclic GMP increased with the deterioration of cardiac function. Plasma cyclic GMP concentrations were correlated positively to the cardiothoracic ratios (CTR), PEP/LVET, and the intracardiac diameters measured by echocardiography respectively (r = 0.55 r = 0.50, and r = 0.55, P less than 0.001), and were correlated negatively to the left ventricular ejection fractions (LVEF) and LV short axis shortenings (LVSAS) (r = -0.53 and r = -0.50 respectively, P less than 0.001). There were only weak correlations between plasma cyclic AMP concentrations and CTR, PEP/LVET ratios, LVEF and LVSAS (r = 0.35, r = 0.38, r = 0.28, and r = -0.31, respectively, P less than 0.01). The correlations between plasma cyclic GMP concentrations and mean pulmonary artery pressures (r = 0.48, P less than 0.05) and mean left atrial pressures (r = 0.55, P less than 0.01) were also significant. In patients who had received cardioversion and valve replacement, plasma cyclic GMP concentrations decreased significantly. Thus the plasma concentrations of cyclic nucleotides could be used as a useful parameter in evaluation of cardiac function and therapeutic effect.

Inhibition of initiation of simian virus 40 chromosome synthesis by dihydroxyanthraquinone

The mode of action of dihydroxyanthraquinone, a new antitumor drug, on eucaryotic chromosome structure and function was investigated using simian virus 40 as a model system. Dihydroxyanthraquinone specifically inhibited initiation of viral replicons. Little or no viral DNA synthesis was recovered in cells after the removal of the drug. Elongation and termination of DNA already initiated could proceed continuously to completion in drug-treated cells. The drug appeared to be stably associated with viral chromosomes in cells. The irreversible inhibition of replicon initiation might contribute to its anti-proliferative and anti-neoplastic activity.