Construction and characterization of a bovine bacterial artificial chromosome library

A bacterial artificial chromosome (BAC) library has been constructed for use in bovine genome mapping using constructed for use in bovine genome mapping using the pBeloBAC11 vector. Currently, the library consists of 23,040 clones, which achieves a 70% probability (P=0.70) of the library containing a specific unique DNA sequence. Sixty thousand clones, or about three haploid bovine genomes, will be required to achieve a 95% probability (P=0.95) of containing a unique sequence. An average insert size of 146 kb was estimated from the analysis of 77 randomly selected BAC clones produced by one or two rounds of size selection. The bovine DNA inserts proved to be very stable for at least 100 cell generations. No chimeric clones were detected among 11 large, size-selected BAC clones using fluorescence in situ hybridization (FISH) on metaphase bovine chromosomes. Thirty-three of 46 (72%) sequences were present in the library in at least one copy, which is consistent with the estimated 70% probability of this library containing a unique DNA sequence. A BAC clone as sequence-tagged sites for genetic mapping. These markers cosegregated, and no recombinants were detected in 193 informative meioses. Plasmid end rescue and the inverse polymerase chain reaction methods were used to rescue both ends of this BAC clone, and chromosome walking was performed using PCR primers designed within the end region sequences. Based on our experimental results, the BAC system provides a very useful tool for complex genome analysis.

[Interleukin-2 gene cloning and expression in S. cerevisiae]

Mature human Interleukin-2 gene was amplified from IL-2 cDNA by PCR methods. The PCR product was cloned into pUC12 plasmid at Sma I site, then precisely engineered into an intermidiate vector pSK43SB which were digested with Hind III, mung bean nuclease, and Sal I. Added BamH I linker to Cla I site of pSK43SB-IL2 to produce one more BamH I site, then digested pSK43DB-IL2 with restriction enzyme BamH I, the BamH I fragment with an alpha-factor leading sequence, IL2 gene and cycl terminater were produced. It was then cloned into a typical high efficiency episomal expression vector YEpHc8. Human IL-2 protein was purified from supernatant secreted by yeast transformants of YEpHc8-IL2 leading by alpha-factor promoter with IL-2 right translational reading frame and accurate cleavage site. High level expression of IL-2 with highly activity has been purified. A sugar specific silver staining method and 3H sugar labelling experiment has shown the detection of carbohydrate component.

Mild hyperthermia can induce adaptation to cytogenetic damage caused by subsequent X irradiation

Many low-level environmental agents are able to induce an increased resistance to subsequent mutagenic effects induced by ionizing radiation. In this paper, an induced cytogenetic adaptation to radiation in human lymphocytes was studied with mild hyperthermia as the adaptive treatment and compared with that induced by low-dose radiation. We found that this adaptation could be induced not only in PHA-stimulated human lymphocytes (at 14, 38 and 42 h after addition of PHA), but also in unstimulated G0-phase cells (before addition of PHA) by mild hyperthermia (41 degrees C for 1 h) as well as 50 mGy X rays. When the two adaptive treatments were combined, no additive effects on the magnitude of the adaptation induced were observed, suggesting that low-dose radiation and hyperthermia may share one mechanism of induction of adaptation to cytogenetic damage. Some mechanisms which may be involved in the induction of adaptation to cytogenetic damage by low-dose radiation are discussed and compared with the effects of mild hyperthermia in inducing thermotolerance and radioresistance.

Mechanistic evaluation of new plant-derived compounds that inhibit HIV-1 reverse transcriptase

Swertifrancheside [1], a new flavonone-xanthone glucoside isolated from Swertia franchetiana, 1 beta-hydroxyaleuritolic acid 3-p-hydroxybenzoate [2], a triterpene isolated from the roots of Maprounea africana, and protolichesterinic acid [3], an aliphatic alpha-methylene-gamma-lactone isolated from the lichen Cetraria islandica, were found to be potent inhibitors of the DNA polymerase activity of human immunodeficiency virus-1 reverse transcriptase (HIV-1 RT), with 50% inhibitory doses (IC50 values) of 43, 3.7, and 24 microM, respectively. They were not cytotoxic with cultured mammalian cells. The kinetic mechanisms by which compounds 1-3 inhibited HIV-1 RT were studied as was their potential to inhibit other nucleic acid polymerases. Swertifrancheside [1] bound to DNA and was shown to be a competitive inhibitor with respect to template-primer, but a mixed-type competitive inhibitor with respect to TTP. On the other hand, 1 beta-hydroxyaleuritolic acid 3-p-hydroxybenzoate [2] and protolichesterinic acid [3] were mixed-type competitive inhibitors with respect to template-primer and noncompetitive inhibitors with respect to TTP. Therefore, the mechanism of action of 1 beta-hydroxyaleuritolic acid 3-p-hydroxybenzoate [2] and protolichesterinic acid [3] as HIV-1 RT inhibitors involves nonspecific binding to the enzyme at nonsubstrate binding sites, whereas swertifrancheside [1] inhibits enzyme activity by binding to the template-primer.

[Expression of desmoplakin II in tumors]

Desmoplakin II (DPII) is a new marker for identification of epithelium and epithelial tumors. Expression of DPII in 217 tumors cases was studied immunohistochemically by ABC method using an anti-DPII monoclonal antibody which reacts with tissue on formalin-fixed, paraffin-embedded sections. A monoclonal antibody against cytokeratin (CK) was employed to compare with the antibody. Immunohistochemical staining showed that 147 of the 163 epithelial tumors and bi-directional differentiation tumors expressed DPII (90.7%); 92 of the 163 tumors expressed CK (56.4%); 54 tumors lacking desmosome expressed neither DPII nor CK. All CK positive staining was located in cytoplasm while most DPII positive dotty staining was located at the cell-cell borders, some DPII staining was present in cytoplasm. These results demonstrate that the anti-DPII monoclonal antibody is a useful immunohistochemical probe for identification of desmosome-containing tumors. Antibodies against other epithelial markers such as keratin should be employed together with anti-DPII monoclonal antibody when differentiation is made between epithelial and non-epithelial tumors.

Metallothionein protects DNA from copper-induced but not iron-induced cleavage in vitro

Iron and copper ions mediate generation of reactive oxygen radicals from O2 and H2O2 by the Fenton reaction: these radicals are capable of damaging DNA. We studied (a) the ability of these metals to induce double-strand breaks in DNA in vitro in the presence of H2O2 and ascorbic acid as donors of reactive oxygen, and (b) the ability of the metal-binding protein metallothionein (MT) to protect DNA from damage. Strand cleavage was measured by loss of fluorescence after binding to ethidium bromide and by increased mobility of DNA in agarose. The results show that Cu(II), Fe(II) and Fe(III) all can induce damage to calf thymus DNA under our experimental conditions. Cu(II)-induced DNA damage was dose-dependent and the degree of damage was proportional to the concentration of H2O2. On the other hand, DNA fragmentation was significant only in the presence of high concentrations of Fe(II) or Fe(III). Addition of Zn-MT to the reaction mixture prior to addition of Cu(II) inhibited fragmentation of DNA in a dose-dependent manner but had little effect on iron induced damage. Other proteins (histone or albumin) were not effective in protecting DNA from Cu-induced damage, as compared to Zn-MT. The formation of Cu(I) from Cu(II) in the presence of hydrogen peroxide and ascorbate was also inhibited by addition of Zn-MT. Thus, MT may protect DNA from damage by free radicals by sequestering copper and preventing its participation in redox reactions.

A metal-dependent form of protein phosphatase 2A

Highly purified bovine heart protein phosphatase 2A catalytic subunit lost virtually all of its activity during storage at -70 degrees. When the enzyme was preincubated with Co2+, over 35% of the original activity was restored. Freshly prepared protein phosphatase 2A purified from bovine heart was stimulated at least 3 to 4-fold by pretreatment with Co2+ or Mn2+. Activation by Co2+ appeared to be irreversible whereas activation by Mn2+ was partially reversed after the cation was chelated with excess EDTA/EGTA. The sensitivity of Co2(+)-stimulated protein phosphatase 2A to okadaic acid or inhibitor-2 was similar to that of spontaneously active protein phosphatase 2A. The enzyme was converted to a latent form by treatment with phosphate or pyrophosphate. The latent form was completely reactivated by preincubation with Co2+. These results demonstrate that protein phosphatase 2A, like phosphatase 1, can exist in a metal ion-dependent form and may represent a new mechanism for the regulation of protein phosphatase 2A activity.

Induction of a cytogenetic adaptive response in germ cells of irradiated mice with very low-dose rate of chronic gamma-irradiation and its biological influence on radiation-induced DNA or chromosomal damage and cell killing in their male offspring

In earlier studies we have shown that either a single exposure or multiple exposures to a low dose of X-rays (0.05 Gy) induced a significant cytogenetic adaptive response in mouse germ cells. In this paper, a very low-dose rate (20 microGy/min) of chronic 60Co gamma-irradiation was used to pre-irradiate mice for 40 days. Then, another 40 days later, these mice were treated with a subsequent large dose of X-irradiation, followed 24 h later by cytogenetic analysis of their spermatocytes. Analysis for radiation-induced DNA and chromosomal damage was also carried out in splenocytes, bone marrow cells and spermatocytes of the offspring of mice adapted by the low-dose rate of chronic gamma-irradiation. Results demonstrated that (i) cumulative gamma-irradiation (1.10 Gy) at the dose rate 20 microGy/min induced a marked cytogenetic adaptive response in the mouse germ cells (stem spermatogonia); (ii) the sensitivity of offspring's bone marrow cells and spermatocytes to 1.5 Gy X-ray-induced chromosome aberrations was not influenced by the low-dose radiation delivered to paternal germ cells; (iii) either constitutive or post-irradiation DNA repair capacity (UV-induced unscheduled DNA synthesis, UDS) was not modified in the offspring's splenocytes; (iv) the sensitivity of the offspring's splenocytes to radiation-induced cell killing was also not altered. These results suggest that low-dose radiation delivered to the male parents with a significant induction of cytogenetic adaptive response in their germ cell does not likely cause any risk of damaging effects to the offspring of those irradiated male mice.

[Report of a case of glucagonoma misdiagnosed as "eczema" and "hepatic angioma" for three years and review of literature]

Glucagonoma is a rare pancreatic tumor, necrolytic migratory erythema is its distinctive feature and it is often associated with diabetes mellitus, weight loss, anemia, hypoaminoacidemia, glossitis and stomatitis. We reported a case of glucagonoma misdiagnosed as "eczema" and "benign hepatic anginoma" for 3 years. His blood glucagon level was 1,758 ng/L. The results of abdominal B-mode ultrasonography and CT scan were negative, but selected arteriogram showed a tumor mass between the pancreatic body and tail. Before operation, treatment with octreotide and supply of amino acids were given with improvement of the skin lesion. After resection of the tumor from pancreas, necrolytic migratory erythema disapeared, but his blood level of glucagon and amino acids did not improve. It is suggested that any diabetic patient with chronic skin damage should be checked for blood glucagon level. In suspected cases, selected arteriogram will be helpful for location of the tumor. Vigorous resection of the pancreatic tumor should be done as soon as possible, even though there is already metastases.

Pre-exposure of mice to low dose or low dose rate ionizing radiation reduces chromosome aberrations induced by subsequent exposure to high dose of radiation or mitomycin C

The phenomenon of cytogenetic adaptive and cross-adaptive response induced by low dose irradiation and chemical mutagen in mice is described. We found, firstly, that adaptation can be induced by acute low dose X-irradiation (0-100 mGy). Secondly, a cross-adaptation can occur between X-irradiation and mitomycin C (MMC). And finally, mice pre-exposed to chronic low dose rate 60Co-Gamma irradiation (0-226.0 mGy/day) are less susceptible to chromosome aberration induced by subsequent acute higher X-irradiation. Therefore, our data suggest that radioadaptive response depends on dose, dose rate and time interval. Possible mechanisms are also discussed.

Isolation and structural elucidation of pentacyclic triterpenoids from Maprounea africana

Pentacyclic triterpenoids based on the taraxer-14-ene skeleton with a C-28 attached carboxylic acid group have been isolated from the roots of Maprounea africana. These compounds were identified as 1 beta,2 alpha-dihydroxyaleuritolic acid 2,3-bis-p-hydroxybenzoate [1], 2 alpha-hydroxyaleuritolic acid 3-p-hydroxybenzoate [2], 2 alpha-hydroxyaleuritolic acid 2,3-bis-p-hydroxybenzoate [4], aleuritolic acid 3-p-hydroxybenzoate [5], aleuritolic acid [6], and aleuritolic acid 3-acetate [7]. Compounds 1 and 2 are new triterpene esters. Compound 3 was previously reported as 7 beta-hydroxymaprounic acid 3-p-hydroxybenzoate [13]. However, based on detailed nmr studies, its structure has been revised.

Crystal structure of a four-stranded intercalated DNA: d(C4)

The crystal structure of d(C4) solved at 2.3-A resolution reveals a four-stranded molecule composed of two interdigitated or intercalated duplexes. The duplexes are held together by hemiprotonated cytosine-cytosine base pairs and are parallel stranded, but the two duplexes point in opposite directions. The molecule has a slow right-handed twist of 12.4 degrees between covalently linked cytosine base pairs, and the base stacking distance is 3.1 A. This is in general agreement with the NMR studies. A biological role for DNA in this conformation is suggested.

Myometrial expression of mRNA encoding epidermal growth factor receptor (EGFR) throughout the menstrual cycle

PROBLEM

To investigate the quantitative changes in expression of EGFR mRNA in the myometrium throughout the menstrual cycle.

METHOD

Myometrium was collected at hysterectomy from 27 women with a history of regular cycles. Total RNA (20 micrograms) was isolated and analyzed by Northern blot using a human EGF-R specific 32P-labeled cDNA probe. The hybridization signals were quantified by densitometry, standardized, and reported in densitometry signal units (DSU). Endometrial specimens from the same uteri were simultaneously evaluated for histologic dating of menstrual cycle day. EGFR gene expression in endometrium was previously reported. Statistical significance of the differences in myometrial gene expression between menstrual phases was evaluated by student's t test.

RESULTS

EGFR mRNA was expressed in all myometrial tissues tested. Levels were higher in the late proliferative phase than in all other phases (P < .05). Women over 40 years old had lower proliferative phase expression than younger women.

CONCLUSION

This data suggests that myometrial EGFR mRNA expression varies in association with the histologic phases of the normal menstrual cycle, and may be affected by aging, even when cycles occur at regular intervals.

[Amplification, cloning and sequencing of beta nerve growth factor gene in the Chinese population]

Genomic DNA was extracted from white blood cells. Using the genomic DNA as template, the gene encoding nerve growth factor (beta-NGF) in the Chinese population was amplified using polymerase chain reaction (PCR). The beta-NGF gene obtained by PCR was then cloned into plasmid pUC 12 which was digested with SmaI. After transformation, screening and identification, 8 clones containing the beta-NGF gene were analyzed. Nucleotide sequence of the NGF was determined by dideoxy-nucleotide chain-termination method. The sequencing result showed that there are 6 differences between the beta-NGF sequence of the Chinese population and previous reported beta-NGF sequence.

65 cases of preserving pylorus pancreatoduodenectomy: experience and problems

Sixty-five patients with neoplasm (62 cases) or pancreatitis (3 cases) were treated with preserving pylorus pancreatoduodenectomy (PPPD) from 1984 to 1991. One postoperative death occurred. Follow-up studies were performed in 35 patients who had been treated by PPPD or the standard Whipple's procedure; they were questioned carefully concerning clinical symptoms. Further studies were performed in 20 patients with or without pylorus preservation (10 patients, respectively). Nutritional status and gastrointestinal digestive and absorptive functions were evaluated by determination of serum components, gastric analysis, barium emptying time, D-xylose absorption test, 14CO2 breath test, PABA, and other methods. The results demonstrated malnutrition and postgastrectomy syndromes in some patients after the standard Whipple's procedure, but not in those with PPPD. The quality of life was better in the latter. Pylorus preservation may be the main reason for this above difference. Delayed gastric emptying in the early postoperative period was a complication in some patients (21%) treated by PPPD. We recommend PPPD for pancreatoduodenectomy.

Cytogenetic adaptive response with multiple small X-ray doses in mouse germ cells and its biological influence on the offspring of adapted males

Cytogenetic adaptive response of mouse germ cells was studied by exposing male mice to a sequence of 4 conditioning doses of 0.05 Gy each (D1) administered at 10-day intervals and subsequently to a single challenging dose of 1.5 Gy (D2). In concurrent experiments, male mice after treatment with D1 doses alone were mated to unirradiated females and the F1 males were given the D2 dose. Chromosomal aberrations in both spermatocytes and bone-marrow cells and UV-induced UDS in splenocytes of these mice were studied. Adapted mice (i.e., D1 + D2 exposures) responded with a significantly lower frequency of chromosomal aberrations than the non-adapted (D2 exposure only) controls. The relative reduction in frequencies was, however, similar to that observed in earlier work with a single conditioning dose of 0.05 Gy. The frequencies of chromosomal aberrations in spermatocytes and bone-marrow cells as well as the levels of UV-induced UDS in splenocytes of the F1 males in the group D1 to fathers + D2 to F1 males were the same as those in F1 males which received only the D2 exposure.

Induction of an adaptive response to dominant lethality and to chromosome damage of mouse germ cells by low dose radiation

In the present paper, dominant lethal mutations, chromosome aberrations in spermatocytes and reciprocal translocations in stem spermatogonia were analyzed after whole body exposure of mice to X-radiation. Results both from chromosome aberrations in spermatocytes and for reciprocal translocations in spermatogonia showed that pre-exposure to low doses up to 200 mGy could induce a significant dose-dependent reduction in adapted mice compared to the non-adapted mice; the lower the adaptive dose, the greater the reduction. For dominant lethal mutations, it was found that spermatogonia (both stem cells and differentiated cells) and spermatocytes adapted to 50 mGy X-rays could show an adaptive response, but spermatids and spermatozoa could not.

Endometrial expression of mRNA encoding epidermal growth factor receptor in normal and leiomyomatous uteri throughout the menstrual cycle

PROBLEM

To investigate the relationship between the histologic phase and the quantitative expression of epidermal growth factor receptor (EGFR) mRNA in the endometrium of normal and leiomyomatous uteri.

METHODS

To test this relationship, endometrium was collected at hysterectomy from 38 women with a history of regular cycles. Total RNA (20 micrograms) was isolated and analyzed by Northern blot using a human EGFR-specific 32P labeled cDNA probe. The hybridization signals were quantified by densitometry, standardized, and reported in densitometry signal units. Separate portions of the same endometrial specimens were simultaneously prepared for histologic evaluation. The differences between menstrual phases were evaluated by Student's t-test.

RESULTS

EGFR mRNA was expressed in all endometrial tissues tested. Levels were higher in the midproliferative phase than in all other phases for both myomatous and nonmyomatous uteri (P < .05). Myomatous uteri showed lower expression than nonmyomatous uteri in the early and late proliferative phase (P < .05). Age did not appear to alter endometrial EGFR mRNA expression.

CONCLUSION

This data suggest that endometrial EGFR mRNA expression varies in association with the histologic changes of the normal menstrual cycle, and may be associated with the presence of leiomyomata uteri.

A physiological role of peptide YY on exocrine pancreatic secretion in rats

BACKGROUND

Peptide YY (PYY) given intravenously was shown to inhibit pancreatic exocrine secretion both in the dog and the rat. However, a possible physiological role of PYY on the pancreatic secretion has not been clarified. The present study was undertaken to investigate its physiological role on the exocrine pancreas.

METHODS

In conscious rats, plasma PYY was determined in response to oral ingestion of a 6-mL meal and intravenous infusion of PYY; small intestinal transit time was measured by phenol red as a nonabsorbable marker, and pancreatic secretory studies were performed in rats with pancreatic fistulas and jugular vein catheters.

RESULTS

Oral ingestion of the meal (containing phenol red, 1.6 mg/100 mL) significantly increased plasma PYY within 30 minutes. During this period, most (97%) of the phenol red was detected in the proximal two-thirds of the small intestine. Intravenous infusion of PYY in 25, 50, and 100 pmol.kg-1 x h-1 produced a dose-dependent increase in plasma PYY. The dose of PYY that simulated the peak postprandial level was 50 pmol.kg-1 x h-1, and this dose of PYY significantly inhibited the pancreatic secretion stimulated by physiological doses of secretin and cholecystokinin-8 (CCK-8). After the meal, pancreatic secretion of bicarbonate and protein significantly increased in rats pretreated with normal rabbit serum, whereas this increase was significantly augmented in rats pretreated with an anti-PYY serum because the postprandial increase in plasma PYY was abolished.

CONCLUSIONS

PYY plays a regulatory role in the postprandial pancreatic exocrine secretion in rats.

Serological evidence of Coxiella burnetii infection in wild animals in Japan

One hundred and thirty-four (26%) of 511 sera from 11 wild animal species in eight prefectures in Japan had antibody titers to Coxiella burnetii by the enzyme-linked immunosorbent assay. High prevalences were observed in Japanese black bears (Ursus thibetanus) (78%), Hokkaido deer (Cervus nippon yesoensis) (69%), Japanese hares (Lepus brachyurus) (63%), Japanese deer (Cervus nippon centralis) (56%), and to some extent in Japanese monkeys (Macaca fuscata) (28%). A low prevalence (13%) was observed in nutrias (Myocastor coypus). Japanese serows (Capricornis crispus), wild rats (Muroides sp.), raccoon dogs (Nyctereutes procyonoides viverrinus), wild pigs (Sus scrofa leucomystax), and masked palm civets (Paguma larvata) had no detectable antibodies to C. burnetii. Thus, six of 11 wild animal species in Japan were exposed to C. burnetii. Based on the high prevalences in some species, they may be a potential source of infection to both domestic animal and human populations.

Prevention of thrombus growth by antithrombin III-dependent and two direct thrombin inhibitors in rabbits: implications for antithrombotic therapy

We compared the abilities of heparin and two direct thrombin inhibitors to prevent fibrin accretion onto pre-existing thrombi in rabbits. Inhibition of thrombus growth was measured as the ability of each test compound to inhibit the accretion of 125I-fibrin onto thrombi pre-formed in jugular veins of rabbits. When administered as a continuous infusion, the two direct (i.e. antithrombin III-independent) thrombin inhibitors, r-hirudin and a tripeptide, Ac(D)-Phe-Pro-bor-Arg (P-8714) inhibited fibrin accretion as effectively as heparin, but did so in doses which generated little systemic anticoagulation, as compared to the marked anticoagulation associated with the heparin effect. However, both r-hirudin and P-8714 were more effective when they were administered as a single bolus injection than as a continuous infusion. Under the former conditions, there was only a transient systemic anticoagulant effect. We conclude that direct or antithrombin III-independent thrombin inhibitors are more effective than heparin in preventing thrombus growth. The limited effect of heparin is likely due to fibrin impairing the ability of heparin/antithrombin III to inactivate thrombin.

Study on the mechanism of cytogenetic adaptive response induced by low dose radiation

Pre-exposure of human lymphocytes to low dose radiation (D1) could induce a cytogenetic adaptive response expressed as a decrease of chromatid aberrations caused by subsequent large dose radiation (D2). There are two possible explanations for its mechanism, i.e., activation of enzymatic processes by D1 facilitating repair of chromosomal damage and induction of protective proteins by D1 reducing the number of chromosomal aberrations. The results here showed: (1) the cytogenetic adaptive response could be enhanced by hyperthermia (41 degrees C and 43 degrees C) and suppressed by hypothermia (4 degrees C); (2) hyperthermia (41 degrees C) alone could also induce the cytogenetic adaptive response; (3) the cytogenetic adaptive response could be inhibited by cycloheximide--an inhibitor of protein synthesis; (4) supernatant from cultured lymphocytes treated with D1 failed to show the protective effect. The results imply that the cytogenetic adaptive response is not only related to the activation of repair enzymes, but also to the induction of protective proteins.

[A case-control study of stomach cancer in Changle, Fujian Province--by the risk state analysis]

In order to detect the risk factors of stomach cancer in Changle county, a case-control study was undertaken. The present paper reports on the results of risk-state analysis. It showed that taking mildewed and heavily salty food, having bad eating habits, family history of tumour, less consumption of fresh vegetables, meat and bean products were the risk factors of stomach cancer in this county.

[Mechanism of cytogenetic adaptive response induced by low dose radiation]

Cytogenetic observation on human lymphocytes indicated that pre-exposure of 10, 50 and 75 mGy X-rays could induced the adaptive response. Experimental results with different temperature treatment showed that the adaptive response induced by low dose radiation could be enhanced by 41 degrees C and 43 degrees C, but inhibited by 4 degrees C in addition the treatment by 41 degrees C for one hour could also cause the adaptive response as did low dose radiation. Results showed that adaptive response induced by low dose radiation (10 or 50 mGy X-rays) could be eliminated by the protein synthesis inhibitor, implying that the adaptive response is related with the metabolism of cells, especially with the production of certain protective proteins.

Structural analysis of bovine pancreatic thread protein

Pancreatic thread protein (PTP) forms double helical threads in the neutral pH range after purification, undergoing freely reversible, pH-dependent globule-fibril transformation. The purified bovine PTP consists on SDS gels of two carbohydrate-free polypeptide chains (Gross et al., 1985). Plasma desorption mass spectrometry and amino acid sequence analysis now confirm that bovine PTP contains two disulfide-bonded polypeptides, an A chain of 101 amino acid residues with a molecular weight of 11,073 and a B chain of 35 residues with a molecular weight of 3970. The intact protein exhibits a molecular weight of 15,036, agreeing greater than 99.9% with the molecular weight calculated from the sequence. The B chain sequence was determined by gas-phase Edman degradation of the intact polypeptide. The A chain sequence was determined from overlapping peptides generated by cleavage at lysyl, tryptophanyl, and aspartyl-prolyl residues. Based upon the bovine PTP cDNA structure, the two chains of the protein result from cleavage of a single polypeptide with removal of a dipeptide between the NH2-terminal A chain and COOH-terminal B chain. Comparison of bovine PTP with other proteins reveals significant structural relatedness with the single-chain homologues from human and rat pancreas and with the motif associated with Ca2(+)-dependent carbohydrate recognition domains. The physiological role of PTP has not yet been resolved. The protein is present in very high concentration in pancreatic secretion and it has been detected in brain lesions in Alzheimer's disease and Down syndrome and in regenerating rat pancreatic islets. The present results provide a firm protein base for ongoing molecular, physical-chemical, and structure-function studies of this unusual protein.

Induction of cytogenetic adaptive response of somatic and germ cells in vivo and in vitro by low-dose X-irradiation

The cytogenetic adaptive response induced by low-level radiation was studied using human and rabbit lymphocytes in vitro and bone marrow cells and germ cells in vivo. The inductive dose of X-rays was 10 mGy for the in vitro studies at a dose rate of 10 mGy/min, and 2, 10, 50, 75 and 100 mGy for the in vivo studies at a dose rate of 50 mGy/min. The challenging dose was 1.5 Gy X-rays for the in vitro experiments and 0.65 or 0.75 Gy for the in vivo experiments at a dose rate of 0.44 Gy/min. The results reported here, in addition to those that have appeared in the literature, show the following characteristics documented for the first time: (1) 10 mGy could induce the adaptive response in human as well as rabbit lymphocytes irradiated not only in G1, S and G2 phases, but also in the Go state; (2) although the induced adaptive response could only last three cell cycles, it could be revived when the inductive dose was repeated after the third cell cycle; (3) the adaptive response could be induced by low-dose X-rays in somatic cells, both in vitro (lymphocytes) and in vivo (bone marrow cells), and also in germ cells (spermatocytes); (4) the magnitude of the adaptive response induced by whole-body irradiation was found to be dose-dependent--the lower the inductive dose the more the reduction of the frequency of chromatid aberrations following the challenging dose.

Neutralization of enoxaparine-induced bleeding by protamine sulfate

It has been suggested that protamine sulfate is a poor antidote for the bleeding side-effects of low molecular weight heparins (LMWHs) in vivo, since protamine sulfate does not completely neutralize the anti-factor Xa activity of LMWHs in vitro or ex vivo. Therefore, we performed experiments to compare directly the abilities of protamine sulfate to neutralize the anticoagulant activities of the LMWH, enoxaparine, and unfractionated heparin ex vivo, with its ability to neutralize the bleeding side-effects of both compounds in vivo. Bleeding was measured as the amount of blood lost from 5 cuts made in rabbits ears before and after treatment with enoxaparine or unfractionated heparin +/- protamine sulfate. Plasma anti-factor Xa and anti-thrombin activities ex vivo, were measured chromogenically. Doses of 400 and 1,500 anti-factor Xa U/kg of heparin and enoxaparine, respectively, were required to enhance blood loss to the same extent. Protamine sulfate completely neutralized blood loss induced by both compounds, but did not neutralize the anti-factor Xa nor antithrombin activities ex vivo. We conclude that protamine sulfate is an effective antidote for the bleeding side-effects of enoxaparine and unfractionated heparin, despite its inability to completely neutralize their anticoagulant activities.

[PSD-007 luminescence in the diagnosis of exfoliative cells from malignant tumors]

This paper presents the first report in China on the use of luminescence method with hematoporphyrin derivative PSD-007 in the analysis of the exfoliative malignant cells. By this method, pleurorrhea and ascites from 226 suspicious patients were detected. The results showed that its positive rate was 42.23% higher than that of Wright's stain and its positive conformation rate to HE stain could reach as high as 90.2%. Especially, cancer cells could be distinguished from various kinds of non-cancer cells by an objective quantitative analysis of the cellular fluorescent intensity using microfluorophotometer. This new method, being simple, economical and highly specific, is used not only in the qualitative study of the exfoliative tumor cells, but also in the quantitative analysis.