Generation of expressed sequence tags of random root cDNA clones of Brassica napus by single-run partial sequencing

Two hundred thirty-seven expressed sequence tags (ESTs) of Brassica napus were generated by single-run partial sequencing of 197 random root cDNA clones. A computer search of these root ESTs revealed that 21 ESTs show significant similarity to the protein-coding sequences in the existing data bases, including five stress- or defense-related genes and four clones related to the genes from other kingdoms. Northern blot analysis of the 10 data base-matched cDNA clones revealed that many of the clones are expressed most abundantly in root but less abundantly in other organs. However, two clones were highly root specific. The results show that generation of the root ESTs by partial sequencing of random cDNA clones along with the expression analysis is an efficient approach to isolate genes that are functional in plant root in a large scale. We also discuss the results of the examination of cDNA libraries and sequencing methods suitable for this approach.

Cell survival in rabbit gastric glands: effect of extracellular pH, osmolarity, and anoxia

Although backdiffusion of luminal acid is regarded as a common mechanism of gastric injury, the extracellular pH (pHo) at which cells are irreversibly injured is not well defined. Exclusion of the fluorescent dye propidium iodide was used to estimate cell survival in rabbit gastric glands incubated in buffers of pHo 8.0-2.0. Mean survival (+/- SE) for n = 6 experiments at 2 h in a HEPES buffer of 300 mosM at pHo 8.0, 7.0, 6.0, 4.0, and 2.0 was 80 +/- 3, 91 +/- 2, 90 +/- 2, 71 +/- 2, and 17 +/- 4%, respectively. Survival at acidic pHo was improved in a high KCl buffer: 78 +/- 3 and 38 +/- 7% at pHo 4.0 and 2.0, respectively. Survival in HCO3- buffers was 73 +/- 3, 88 +/- 2, and 92 +/- 3% at pHo 8.0, 7.4, and 6.0. Brief (5 min) exposure to pHo 4.0 followed by reexposure to pHo 7.4 had no effect on acid secretion as estimated by [14C]aminopyrine uptake or cellular viability over 4 h. The influence on cell survival of changes in pHo under conditions of chemical anoxia and in buffers of different osmolarity was investigated. Chemical anoxia was induced using 2.5 mM KCN and 2.0 mM iodoacetic acid (IAA) to inhibit oxidative phosphorylation and anaerobic glycolysis. Survival in glands exposed to KCN and IAA in HEPES buffer was 54 +/- 5, 82 +/- 3, and 87 +/- 2% at pHo 8.0, 7.0, and 6.0.(ABSTRACT TRUNCATED AT 250 WORDS)

Two putative protein kinases from Arabidopsis thaliana contain highly acidic domains

Two cDNA clones (ASK1 and ASK2) for plant protein kinases were cloned from Arabidopsis thaliana by screening cDNA libraries with a degenerate oligonucleotide probe that corresponds to a highly conserved motif among protein kinases. Sequence analysis shows that the clones contain open reading frames that encode 41.2 kDa (ASK1) and 40.1 kDa (ASK2) proteins, respectively. These coding regions contain all the conserved motifs of protein kinases. Structural analysis of the coding regions revealed that the two protein kinase genes share high sequence similarity to each other (76.6% identity). The catalytic domain located in the amino terminal region is most similar to the calcium/calmodulin-dependent protein kinase subfamily (47.2% to 54.2% similarity) and the SNF1 kinase subfamily (48.1% to 53.3% similarity). However, the carboxy terminal regions contain distinctive stretches of 21 (ASK1) and 19 (ASK2) acidic amino acids. These clones are the first report of protein kinases with such acidic amino acid regions. The transcripts of both genes are most abundant in leaf but are also expressed in other organs. The expression of the two genes is highly affected by light regime.

Hepatitis C is a poor prognostic indicator in black kidney transplant recipients

BACKGROUND

The significance of hepatitis C in kidney transplant recipients is unclear. The prevalence of antibodies to hepatitis C among candidates for transplantation is up to 50% in some centers.

METHODS

We screened 640 frozen serum samples obtained pretransplantation from all kidney recipients at the Medical College of Wisconsin between January 1979 and March 1990 for antibody to hepatitis C using the second generation immunoassay. Charts were reviewed from all hepatitis C antibody-positive (anti-HCV+) patients and 256 randomly chosen hepatitis C antibody negative (anti-HCV-) controls. Actuarial patient and graft survival in these two groups were determined.

RESULTS

The prevalence of anti-HCV was 8.3%. Blacks and i.v. drug users were disproportionately represented in the anti-HCV+ group. Of the anti-HCV+ patients, 18.9% developed chronic hepatitis independent of race. Black anti-HCV+ patients had a 5-year graft survival of 28 +/- 11% compared to 67 +/- 7% in black anti-HCV- patients (P = 0.003). Black anti-HCV-, white anti-HCV-, and white anti-HCV+ patients all had similar graft survival. Anti-HCV was not a poor prognostic indicator for overall patient survival or the development of aplastic anemia and malignancies including hepatocellular carcinoma.

CONCLUSIONS

Anti-HCV is a significant risk factor for reduced kidney graft survival in blacks apart from i.v. drug abuse. Black anti-HCV- patients had graft survival similar to white transplant recipients, indicating that anti-HCV may be one marker for the poorer graft survival in blacks that has been observed in most transplant programs. Anti-HCV in kidney transplant recipients increases the risk for the development of chronic hepatitis post-transplant.

Structures of quinone imine metabolites related to the anti-cancer drug amsacrine

(5): N-(9-Acridinyl)-3-methoxy-1,4-benzoquinone monoimine, C20H14N2O2, M(r) = 314.3, monoclinic, P2(1)/c, a = 13.451 (8), b = 7.007 (4), c = 17.864 (12) A, beta = 117.26 (4) degrees, V = 1497 (2) A3, Z = 4, Dm = 1.36 (1), Dx = 1.395 g cm-3, Mo K alpha, lambda = 0.71069 A, mu = 0.99 cm-1, F(000) = 656, T = 138 (5) K, R = 0.049 for 1556 reflections. (8): N-(9-Acridinyl)-2-methoxy-1,4- benzoquinone monoimine, C20H14N2O2, M(r) = 314.3, triclinic, P1, a = 9.365 (1), b = 13.318 (2), c = 6.918 (3) A, alpha = 96.45 (3), beta = 105.30 (2), gamma = 110.11 (1) degrees, V = 761.6 (4) A3, Z = 2, Dm = 1.35 (1), Dx = 1.371 g cm-3, Mo K alpha, lambda = 0.71069 A, mu = 0.98 cm-1, F(000) = 328, T = 292 (1) K, R = 0.075 for 1009 reflections. (13): N-(9-Acridinyl)-5-dimethylamino-2- methoxy-1,4-benzoquinone monoimine, C22H19N3O2, M(r) = 357.4, triclinic, P1, a = 8.091 (7), b = 10.078 (2), c = 11.716 (3) A, alpha = 108.39 (2), beta = 99.63 (4), gamma = 95.87 (3) degrees, V = 881.4 (9) A3, Z = 2, Dm = 1.33 (1), Dx = 1.347 g cm-3, Mo K alpha, lambda = 0.71069 A, mu = 0.95 cm-1, F(000) = 376, T = 173 (5) K, R = 0.034 for 1460 reflections. The molecular geometries are described and discussed.

Cloning, sequencing, purification, and Gq-dependent activation of phospholipase C-beta 3

Six mammalian phospholipase C isozymes (PLC-beta 1, PLC-beta 2, PLC-gamma 1, PLC-gamma 2, PLC-delta 1, and PLC-delta 2) have been identified at both protein and DNA levels. Here, cDNAs corresponding to a previously unidentified PLC isozyme were isolated from a rat thyroid cell FRTL cDNA library. Comparison of the predicted amino acid sequence of this new PLC with other known PLC isozymes revealed a high degree of overall similarity with PLC-beta 1 and PLC-beta 2. Thus, the new PLC was named PLC-beta 3. Comparison with PLC-beta 1 and PLC-beta 2 also revealed that the deduced amino-terminal sequence of PLC-beta 3 was incomplete by 10-20 amino acids. With the use of antibodies raised against synthetic peptides corresponding to PLC-beta 3-specific amino acid sequences, we purified PLC-beta 3 from a rat brain particulate fraction. The purified enzyme exhibited an apparent molecular mass of 152 kDa on SDS-polyacrylamide gels, as compared with 150 and 140 kDa for PLC-beta 1 and PLC-beta 2, respectively. Studies of the activation of PLC-beta isozymes by three alpha subunits of Gq class G proteins, alpha q, alpha 11, and alpha 16 in the presence of guanosine 5-O-(3-thiotriphosphate) (GTP gamma S) revealed that the extent of activation decreased in the order of PLC-beta 1 > or = PLC-beta 3 >> PLC-beta 2 for all three alpha subunits, suggesting a certain degree of specificity in the interaction of Gq alpha subunits with different PLC-beta isozymes.

Cloning, sequencing, and expression of a minor protease-encoding gene from Serratia marcescens ATCC21074

The gene (smp) encoding an extracellular protease (Smp) from Serratia marcescens ATCC21074 has been cloned and expressed in Escherichia coli HB101. The nucleotide (nt) sequence of the cloned smp gene revealed a single open reading frame of 1056 bp coding for 352 amino acids (aa) (38,479 Da). The N-terminal aa sequence of Smp excreted from the E. coli host cells revealed that mature Smp consists of 300 aa (32,515 Da). The deduced aa sequence of Smp showed high overall homology (43%) to the Erwinia carotovora metalloprotease, but low homology (15-20%) to other metalloproteases, including the S. marcescens major metalloprotease. The location for three zinc ligands and the active site for Smp was predicted from other metalloproteases. The biochemical properties of Smp show that this enzyme is a metalloprotease whose activity is optimal at pH 8.0 and 50 degrees C.

Effects of prenatal alcohol exposure on uncoupling protein in brown adipose tissue in neonatal rats

Thermoregulatory deficits observed in neonatal rats exposed prenatally to alcohol may be due to peripheral and/or central dysfunction. One of the major mechanisms available to newborn mammals to generate heat is "nonshivering thermogenesis" in brown adipose tissue (BAT). In this study, the effects of prenatal alcohol exposure on the functional status of brown adipose tissue was assessed by immunoblot analysis of the content of mitochondrial uncoupling protein (UCP). BAT excised from 1- and 20-day-old male and female offspring from either alcohol-treated, pair-fed controls or standard control dams were analyzed. There were no effects of prenatal alcohol exposure on the UCP content. There was, however, a significant increase due to age. These results suggest that thermoregulatory deficits seen in alcohol-exposed offspring are not due to a deficiency in the concentration of mitochondrial UCP, and indicate a more central mechanism.

An investigation of the sequence-specific interaction of cis-diamminedichloroplatinum(II) and four analogues, including two acridine-tethered complexes, with DNA inside human cells

The sequence specificity of DNA damage caused by cis-diamminedichloroplatinum(II) (cisplatin) and four analogues in human (HeLa) cells was studied using Taq DNA polymerase and a linear amplification system. The primer extension is inhibited by the drug-DNA adducts, and hence the sites of these lesions can be analyzed on DNA sequencing gels. The repetitive alphoid DNA was used as the target DNA in human cells. A comparison was made between adduct formation in human cells and in purified DNA. The sequence-specific position and relative intensity of damage was similar in both systems for cisplatin, dichloro(ethylenediammine)platinum(II) (PtenCl2), and N-[3-N-(ethylenediamino)propyl]acridine-4-carboxamidedichloropl atinum(II) (4AcC3PtenCl2). However, no DNA damage could be detected in cells for trans-diamminedichloroplatinum(II) (transPt) or N-[3-N-(ethylenediamino)propyl]acridine-2-carboxamide-dichloroplat inum(II) (2AcC3PtenCl2) despite the ability of these latter analogues to damage purified DNA. Cisplatin, PtenCl2, and 4AcC3PtenCl2, which significantly damaged DNA inside cells, also show antitumor activity in mouse models. However, transPt and 2AcC3PtenCl2, which did not detectably damage DNA inside cells, did not show such antitumor activity. This correlation between intracellular DNA damaging ability and in vivo antitumor activity indicates the potential use of the human cells/Taq DNA polymerase/linear amplification technique as a convenient method for screening new cisplatin analogues for useful chemotherapeutic activity.

The use of Taq DNA polymerase to determine the sequence specificity of DNA damage caused by cis-diamminedichloroplatinum(II), acridine-tethered platinum(II) diammine complexes or two analogues

cis-Diamminedichloroplatinum(II) (cisplatin) forms adducts with DNA. The sequence specificity of formation of cisplatin adducts with plasmid DNA was investigated using Taq DNA polymerase. This procedure involved the extension of an oligonucleotide primer by Taq DNA polymerase up to the cisplatin adduct. Using thermal cycling, this process is repeated many times in order to amplify the signal. The products of this linear amplification can then be examined on DNA sequencing gels, and the sequence specificity of cisplatin adduct formation can be determined to the exact base pair. In the pUC8 plasmid, the sequences that produced the most intense damage sites (as determined by densitometry) were runs of two or more Gs. Adducts could also be detected at GA, AG, and GC dinucleotides. Four other cisplatin analogues were also tested in the system. Two of these analogues contained an attached intercalating chromophore, and the strong damage with these compounds was similar to that found for cisplatin, but the medium and weak damage tended to be different. Weak damage was also detected with trans-diamminedichloroplatinum(II). With this compound, a large number of the damage sites were at the CG dinucleotide. This technique represents a simple, accurate, and quick method for determining the sequence specificity of damage for a cisplatin analogue in any DNA sequence.

Mutational analysis by a combined application of the multiple restriction fragment-single strand conformation polymorphism and the direct linear amplification DNA sequencing protocols

We describe here an improved procedure for polymerase chain reaction (PCR)-based single strand conformation polymorphism (SSCP) for rapid mutational detection. To circumvent the restriction of having to analyze relatively short PCR fragments, restriction endonucleases were used to cleave a longer PCR product and the mixture of fragments was analyzed directly in SSCP gel electrophoresis. This multiple restriction fragment (MRF)-SSCP protocol was demonstrated by the detection of a 4-bp deletion in codons 41-42 and a point mutation in the IVS-2 sequence of the human beta-globin gene. The MRF-SSCP or the standard SSCP protocol was then combined with the linear amplification DNA sequencing (LADS) procedure for direct analysis of the PCR products without further purification for an exact characterization of the mutations detected. In the LADS analysis, homo- or heterozygosity of a mutation was easily distinguished by the appearance of a single- or double-lane band in the sequencing gel. The choice of isotope used and different labeling methods were compared and were found, in some cases, to produce SSCP patterns of different complexities. The combined MRF-SSCP/LADS protocol permits rapid mutational analysis of a large number of clinical samples using only very small amounts of materials and can easily be adopted for nonisotopic clinical applications.

DNA-directed alkylating agents. 5. Acridinecarboxamide derivatives of (1,2-diaminoethane)dichloroplatinum(II)

A series of acridine-2- and -4-carboxamide-linked analogues of PtenCl2 has been prepared and evaluated for biological activity against several tumor cell lines in vitro and in vivo. The platinum complexes were generally more cytotoxic than the corresponding ligands against wild-type P388 leukemia cells in vitro, with acridine-4-carboxamide complexes being the more effective. In contrast to cisplatin and PtenCl2, the complexes were equally active in vitro against both wild-type and cisplatin-resistant P388 lines. The 4-carboxamide complexes showed high levels of in vivo activity (ILS greater than 100%) against wild-type P388 using a single-dose protocol, and one compound was also significantly active in vivo in a cisplatin-resistant line, against which cisplatin and PtenCl2 are inactive.

Potential antitumor agents. 64. Synthesis and antitumor evaluation of dibenzo[1,4]dioxin-1-carboxamides: a new class of weakly binding DNA-intercalating agents

A series of substituted dibenzo[1,4]dioxin-1-carboxamides has been synthesized and evaluated for in vitro and in vivo antitumor activity. The required substituted dibenzo[1,4]dioxin-1-carboxylic acids were prepared by a variety of methods. No regiospecific syntheses were available for many of these, and separation of the mixtures of regioisomers obtained was sometimes difficult. The dibenzo[1,4]dioxin-1-carboxamides are active against wild-type P388 leukemia in vitro and in vivo, with structure-activity relationships resembling those for both the acridine-4-carboxamide and phenazine-1-carboxamide series of DNA-intercalating antitumor agents. In all three series, substituents placed peri to the carboxamide sidechain (the 5-position in the acridines, and the 9-position in the phenazines and dibenzo[1,4]dioxins) enhance activity and potency. The 9-chlorodibenzodioxin-1-carboxamide was also curative against the remotely sited Lewis lung carcinoma. Several of the compounds showed much lower levels of cross-resistance to the P388/AMSA line than classical DNA-intercalating agents, which suggests that their primary mechanism of action may not be via interference with topoisomerase II alpha. This is of interest with regard to the development of drugs to combat resistance mechanisms which arise by the expression of the topo II beta isozyme.

In vitro effects of milbemycin oxime: mechanism of action against Angiostrongylus cantonensis and Dirofilaria immitis

The neuropharmacological mechanisms underlying the action of milbemycin oxime on the motility of Angiostrongylus cantonensis and Dirofilaria immitis were examined in vitro. In A. cantonensis, milbemycin oxime caused inhibitory effects at low concentrations of > or = 10(-9) g/ml, and paralysis was elicited at 10(-8) - 10(-6) g/ml. The paralysis was antagonized by picrotoxin and bicuculline but not by dibenamine. In addition, stimulatory effects were observed when the antibiotic was used at higher concentrations of 3-5 x 10(-6) g/ml, and the action was antagonized by strychnine. Both effects were also observed in the preparation contracted by eserine or pyrantel. When D. immitis was treated with milbemycin oxime at concentrations of 10(-7) and 3-5 x 10(-6) g/ml, only slight inhibitory and stimulatory effects, respectively, were observed. These effects were partially antagonized by picrotoxin and strychnine, respectively. These results suggest that the inhibitory and stimulatory actions of milbemycin oxime are caused through gabergic and cholinergic mechanisms in A. cantonensis and D. immitis.

Pyrazole analogues of the bispyrrolecarboxamide anti-tumour antibiotics: synthesis, DNA binding and anti-tumour properties

Four bispyrazole compounds have been prepared as potentially more stable analogues of the DNA minor groove binding polypyrrole compounds netropsin and distamycin, which are susceptible to oxidative breakdown. These compounds bind less strongly to DNA, and show much lower specificity for binding to AT-rich DNA sequences in comparison with distamycin. N.m.r. studies show that two of these compounds cause a downfield shift of the DNA imino proton resonances on interaction with the oligonucleotide d(ATATATATAT)2, suggesting that these isomers can adopt low-energy conformations similar to that shown by distamycin in its DNA minor groove binding site. The benzoic acid mustard analogue of one of the minor groove binding bispyrazoles was prepared, and showed in vitro cytotoxicity comparable with that of the previously-reported distamycin mustard, but only a low level of activity in vivo.

The 40-kilodalton allergen of Candida albicans is an alcohol dehydrogenase: molecular cloning and immunological analysis using monoclonal antibodies

To characterize the 40-kilodalton (kD) major allergen of Candida albicans (C. albicans), six monoclonal antibodies (MoAbs) against this allergen were generated. In SDS-polyacrylamide gel electrophoresis and immunoblot analysis, these MoAbs showed four different reaction patterns to antigens of six different Candida species. With the exception of one MoAb, other MoAbs were resistant to periodate treatment indicating non-carbohydrate epitopes were probably being recognized by these MoAbs. These MoAbs were used in the molecular cloning and immunological analysis of the gene coding for the 40-kD allergen. Nucleotide sequence determination of the two lambda gt11 cDNA clones obtained showed that the 40-kD allergen is an alcohol dehydrogenase (ADH) which shares a 70% amino acid sequence homology with the ADH isozyme I of Saccharomyces cerevisiae. This finding was confirmed by positive immunological response of the lysates of the clones obtained and a preparation of ADH of Saccharomyces cerevisiae to various MoAbs and to IgE antibodies in sera of allergic patients.

The effects of postnatal caffeine exposure on growth, activity and learning in rats

Caffeine is both ingested by pregnant women in their third trimesters and administered therapeutically to premature infants to stimulate respiration. This experiment attempted to delineate any persistent effects of low dose caffeine exposure during the first week of life in rats, since this time period provides an animal model equivalent to the human third trimester or premature infant exposure. Rat pups who had received either 1 or 9 mg/kg of caffeine during the first week of life grew more slowly, were hypoactive at two weeks of age, and were impaired on an operant spatial learning task as adults. Adding visual cues to the operant task did not improve their performance. The timing of the appearance of developmental landmarks, adult body weight and adult brain weight, however, were not affected by postnatal caffeine exposure. The persistent behavioral deficits noted after postnatal caffeine exposure were all opposite in direction to the acute effects of caffeine, and similar to the effects of adenosine. Thus the behavioral deficits reported here may reflect an upregulation of developing adenosine receptors that persists into adulthood subsequent to early chronic postnatal caffeine exposure.

Regulation of human B cell proliferation and differentiation by seminal plasma

To investigate the role of seminal plasma in human B cell functions, its effect on the proliferation and antibody secretion of tonsillar B cells and an Epstein-Barr virus (EBV) transformed human B cell line, A4, was examined. Seminal plasma inhibited both the proliferation and differentiation of normal B cells only when added to the cultures at the early period of culture. If addition of seminal plasma was delayed beyond 5 to 6 days, it failed to inhibit IgG secretion. Seminal plasma did not show any inhibitory effect on A4 cells, but rather enhanced both the proliferation and IgG secretion of this B cell line. When the low and high mol. wt fractions of seminal plasma were tested for their biological effects on normal and transformed B cells, the low mol. wt fraction (less than 1 kD) was associated with the inhibitory effect of seminal plasma on normal B cells, whereas high mol. wt fractions (both dialysed and 1500-kD fraction) was involved in the enhancing effect on A4 cells. We conclude that (i) seminal plasma inhibits the early proliferation of normal human B cells, but does not inhibit the antibody-secreting capacity of mature B cells; and (ii) different molecules of seminal plasma act on the different stages of B cell maturation.

Relative prevalence and risk factors of HTLV-I and HTLV-II infection in US blood donors

The clinical significance of human T-cell lymphotropic virus type II (HTLV-II) infection, unlike that of HTLV-I, is unknown, and the major known association of HTLV-II seropositivity is with intravenous drug abuse. Screening of blood donors for HTLV-I, now routine in North America, does not distinguish this retrovirus from HTLV-II. To find out more about the seroepidemiology of and risk factors for HTLV I and II, blood from 480,000 volunteer donors in five geographically separate US urban centres was tested for antibodies to HTLV-I/II and HIV-1. Confirmed HTLV-I/II seropositive donors were then followed up by DNA amplification to distinguish type I from type II and by interviews focusing on possible risk factors. HTLV seroprevalence was 3.3 times greater than that for HIV-1 (0.043% vs 0.013%). DNA amplification on 65 of the 207 HTLV-I/II seropositive donors revealed that 34 (52%) had HTLV-II infection and 28 (43% had HTLV-I; 3 samples were uninformative. Interviews of 49 donors showed that whereas HTLV-I was principally associated with donor origin from endemic regions, the major risk factor for HTLV-II infection was intravenous drug use. The surprisingly high rate of HTLV-II infection in US blood donors raises important public health and donor counselling issues since HTLV-I infection is associated with adult T-cell leukaemia and a neurological disorder while the pathogenicity of HTLV-II is as yet unclear.

A new technique for right heart catheterization with a Swan-Ganz balloon catheter via femoral vein in the patient with dilated right heart chambers, utilizing a modified transseptal-type sheath

Right heart catheterization with a Swan-Ganz balloon catheter via femoral vein in the patient with dilated right atrium and ventricle is frequently difficult due to excessive catheter coiling in the dilated atrium. A new technique is described in this situation. By using a modified transseptal-type sheath positioned counterclockwise in right atrium as an introducing sheath, a balloon catheter can be easily advanced to the distal pulmonary artery by smooth counterclockwise direction and secure support from this sheath.

Detection of beta-globin gene mutations by polymerase chain reaction

The polymerase chain reaction and oligonucleotide probe hybridization technique were applied to the detection of two common mutations of the beta-globin gene found in Chinese, namely the 4-base pair deletion at the 41-42 codons and the C to T substitution at nucleotide 654 of IVS-2. The accuracy of the method was established using beta-thalassemia cases with known mutations or haplotypes of the restriction fragment length polymorphism (RFLP). A further 11 cases of thalassemia intermediate and thalassemia minor were then analysed with the same approach. Our results showed that 5 of the 11 cases carried the TCTT-deletion at codons 41-42. Our method is economical both in terms of materials and time needed and in an alternative to the use of the molecular RFLP approach in the prenatal diagnosis of beta-thalassemia.

Accumulation of polycyclic aromatic hydrocarbon-induced single strand breaks is attributed to slower rejoining processes by DNA polymerase inhibitor, cytosine arabinoside in CHO-K1 cells

We demonstrate a successful induction of DNA single strand breaks in CHO-K1 cells by cocultivation with mouse embryonic fibroblasts (MEF) during exposure to benzo(a)pyrene (BP) or 3-methylcholanthrene (MC). When compared to those induced by methyl methanesulfonate (MMS), the DNA single strand breaks induced by BP and MC were markedly accumulated by post-incubation with cytosine arabinoside (araC) and were much more delayed in their rejoining. These results suggest that the active metabolites of BP or MC produced by cocultivation with MEF or microsomal fraction (S-15) result in the formation of large DNA adducts which require an active participation of DNA polymerase alpha(delta) in the polymerization step of excision repair for their removal.

DIFFERENT PATTERNS OF DNA REPLICATION INHIBITION BY BENZO(A)PYRENE AND 3-METHYLCHOLANTHRENE IN MAMMALIAN CELLS IN VITRO

TWO METABOLIC ACTIVATION SYSTEMS, EXEMPLI GRATIA S15 FRACTION AND MOUSE EMBRYONIC FIBROBLAST (MEF) FEEDER LAYER, HAVE BEEN SHOWN TO HAVE EFFECTS ON THE PATTERN CHANGE OF BENZO(A)PYRENE (BP)- AND 3-METHYLCHOLANTHRENE (MC)-INDUCED DNA REPLICATION INHIBITION. THE PRESENT STUDIES WERE PERFORMED IN ORDER TO ELUCIDATE THE MECHANISM OF SUCH EFFECTS IN CHINESE HAMSTER OVARY CELLS (CHO-K1) USING ALKALINE SUCROSE GRADIENT SEDIMENTATION ANALYSIS. WHEN CHO-K1 CELLS WERE TREATED WITH BP IN THE ABSENCE OF METABOLIC ACTIVATION SYSTEM, INHIBITION OF REPLICON INITIATION AND CHAIN ELONGATION WAS OBSERVED AT 12 HR AND AT 24 HR, RESPECTIVELY, REGARDLESS OF THE DOSE, EVEN THOUGH THE LEVEL OF THE OVERALL REPLICATION INHIBITION WAS VERY LOW. HOWEVER, WHEN THESE CELLS WERE TREATED WITH BP OR MC IN THE PRESENCE OF THE S15 FRACTION FOR 1 HR, THE RATE OF DNA SYNTHESIS WAS GREATLY DECREASED. AT LOW DOSES BELOW 10(-6) M WHEREAS THE CHAIN ELONGATION WAS MARKEDLY INTERRUPTED AT 10(-4) M. THESE RESULTS SUGGEST THAT THE PATTERN OF DNA REPLICATION INHIBITION INDUCED BY MC OR BP COULD BE INFLUENCED TO A GREATER DEGREE BY THE CHOICE OF METABOLIC ACTIVATION SYSTEM EMPLOYED THAN BY THE DOSE OR THE DURATION OF EXPOSURE.

DNA-directed alkylating agents. 2. Synthesis and biological activity of platinum complexes linked to 9-anilinoacridine

Two different classes of cis-diaminedichloroplatinum(II) complexes linked to the DNA-intercalating chromophore 9-anilinoacridine have been synthesized and evaluated as DNA-targeted antitumor agents. Two different Pt chelating ligands were investigated (based on 1,2-ethanediamine and 1,3-propanediamine), designed to deliver the Pt in an orientation likely to respectively enhance either intrastrand or interstrand cross-linking. Although both sets of ligands were somewhat unstable under neutral or basic conditions with respect to disproportionation, the corresponding Pt complexes, once prepared, appeared to be quite stable. All the Pt complexes were monitored for purity by TLC, HPLC, and FAB mass spectra, and the mode of Pt coordination was established by 195Pt NMR spectroscopy. The complexes appeared to cause simultaneous platination and intercalative unwinding of plasmid DNA. In vitro studies were carried out with both wild-type and cisplatin-resistant P388 cell lines. Whereas cisplatin itself and the ethylenediamine and 1,3-propanediamine complexes used as standards were about 10-fold less active against the resistant line, the ethylenediamine-linked Pt complexes showed no differential toxicity between the two lines and the propanediamine-linked complexes showed significant differentials (up to 8-fold) in favor of the cisplatin-resistant line. However, these were no greater than those shown by the unplatinated ligands themselves. The majority of the acridine complexes were inactive in vivo against the wild-type P388 leukemia. They were very insoluble, and although a suitable formulation was found, this may have been a factor. It is also possible that these compounds bind in such a way as to direct the Pt away from the major groove.

Analysis of the unoccupied site of an integrated human papillomavirus 16 sequence in a cervical carcinoma

We have previously cloned and analyzed the structure of a type 16 human papillomavirus (HPV16) integration in a primary cervical carcinoma tissue, M50 (Choo et al., J. Virol. 62, 1659-1666, 1988). We found that specific nucleotide sequences within the HPV16 genome influenced the genomic organization of the integrated viral genome. Using the viral-cellular junctions of the M50 DNA as probes, we have now cloned the unoccupied site from a human genomic library. Mapping analysis showed that a deletion of about 1.1 kilobase pairs (kb) had occurred at the integration site of M50. Sequencing of the integration junctions of the unoccupied site and comparison with the viral sequence has revealed short regions of sequence homology between the viral and the cellular genomes at both junctions. Our results are consistent with a mechanism of integration of the HPV16 sequences in the M50 carcinoma involving illegitimate recombination events using short patches of homologous sequences between the two heterologous genomes for anchorage and as guides for crossover. Preferred topoisomerase I cleavage sites and alternating purine and pyrimidine bases, which favor the formation of Z-DNA, could also be identified at the integration regions, supporting a proposed role for the topoisomerase I enzyme in the illegitimate recombination in the viral integration process.

Pancreaticobiliary secretion of zinc and copper in normal persons and patients with Wilson's disease

The objectives of this study were (1) to examine basal and cholecystokinin-stimulated pancreaticobiliary secretion of zinc in normal subjects with zinc-adequate and zinc-deficient diets, and (2) to investigate whether basal and stimulated secretion of zinc was abnormal in patients with Wilson's disease before and after zinc therapy. Gastroduodenal intubation was performed in six healthy subjects and five patients with Wilson's disease. After intravenous infusion of octapeptide of cholecystokinin (40 ng/kg/hr) the pancreaticobiliary secretion of zinc increased from a basal rate of 283.1 +/- 75.8 nmol/L/min to a peak of 716.6 +/- 175.3 nmol/L/min in normal subjects. Normal subjects with a zinc-deficient diet had both lower basal (66.8 +/- 15.8 nmol/L/min) and stimulated (559.5 +/- 31 nmol/L/min) pancreaticobiliary secretion of zinc than with a zinc-sufficient diet. In contrast to the markedly reduced pancreaticobiliary secretion of copper, patients with Wilson's disease not treated with zinc had normal basal (226.6 +/- 126 nmol/L/min) and stimulated (728.7 +/- 195.5 nmol/L/min) zinc secretion. These studies indicate that a considerable amount of zinc is being secreted in pancreaticobiliary fluid in healthy subjects and there was no impairment of zinc secretion in patients with Wilson's disease. Our data also indicate that pancreaticobiliary secretion of zinc is dependent on the zinc status of the subjects, suggesting that endogenous secretion of zinc may play a significant role in the homeostasis of zinc.

Patterns of HIV-1 and HTLV-I/II in intravenous drug abusers from the middle atlantic and central regions of the USA

Seroprevalence of human immunodeficiency virus type 1 (HIV-1) and human T lymphotropic virus types I and II (HTLV-I/II) was determined among 1160 intravenous (iv) drug abusers from five drug treatment or medical centers (Manhattan, Brooklyn, New Jersey, Detroit, and New Orleans). HIV-1 infection ranged from 5% in New Orleans to 48% in New York City. Hispanics and blacks had a significantly higher rate of HIV-1 infection than whites (P less than .01), but within each group rates were similar between males and females and by age stratum. HTLV-I/II seroprevalence increased with age from 3% in the 20-29 year age group to 37% in the group greater than 50 years. New Orleans and Manhattan (24%) had the highest rate, and blacks (19%) had a higher rate than either Hispanics (6.3%) or whites (7.3%). No association between HIV-1 and HTLV-I/II infection was observed except in Manhattan. When compared with iv drug abusers infected only with HIV-1, dually infected subjects had more clinical symptoms related to immune deficiency but a lower prevalence of HIV antigenemia. These data document the frequent occurrence of retroviral infections in iv drug abusers. The contrast between the two classes of virus suggests that HIV-1 is more efficiently transmitted, while the age-dependent rise in HTLV-I/II seroprevalence suggests cumulative exposure of a less-transmissible agent.

Forearm median nerve conduction velocity in carpal tunnel syndrome

Reduced velocity of median nerve conduction in the forearm of patients with carpal tunnel syndrome (CTS) has been attributed to an artifact of the electrodiagnostic method rather than pathophysiologic changes in the forearm segment. Standard nerve conduction velocity (NCV) tests measure the forearm segment in combination with the distal latency and this may not represent an accurate assessment of conduction in the proximal portion of the nerve. A new technique of direct evaluation of the forearm median nerve was developed by the stimulation and recording of the forearm nerve action potential (FNAP) proximal to the wrist. The FNAP measurement was compared to the usual NCV in persons with CTS and control subjects. Forearm median nerve conduction velocities in the CTS group were significantly slower (p less than 0.05) than normal subjects using both FNAP and standard NCV techniques. The finding of decreased conduction speeds by the direct measurement of the forearm segment confirms that the reduced speeds derived from NCV are valid and suggests that retrograde degeneration of the nerve axons may result from entrapment in the carpal tunnel.

Epidemiologic characteristics and multiple risk factors of stomach cancer in Taiwan

Both descriptive and analytical studies were carried out to examine epidemiologic characteristics and multiple risk factors of stomach cancer in Taiwan. The age-adjusted mortality rate of stomach cancer has been decreasing since the early 1970s for both males and females. The male-to-female ratio of the disease has remained around 2:1 in the past three decades. Comparison of the incidence of stomach cancer among Chinese in different countries showed a much lower incidence among Chinese in the USA than those in southeastern Asia. A hospital-based matched case-control study carried out in Taipei metropolitan areas showed a positive association of stomach cancer with blood type A, chronic gastric diseases, cigarette smoking, alcohol drinking, green tea drinking as well as consumption of salted meat, cured meat, smoked food, fried food and fermented beans. There was also a significant negative association between the disease and the consumption of milk.

Influence of Cl- on pH(i) in oxynticopeptic cells of in vitro frog gastric mucosa

The effect of Cl- on intracellular pH (pH(i)) was studied using sheets of frog (Rana catesbeiana) fundic mucosa in which oxynticopeptic cells were selectively loaded with the acetomethoxy ester form of the pH-sensitive fluorescent dye 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF/AM). Before the measurement of pH(i), tissues were exposed to either 10(-5) M forskolin in the serosal solution (stimulated tissues) or 3 x 10(-4) omeprazole in the serosal solution (inhibited tissues). In HCO3- and N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) buffers, pH(i) increased significantly after removal of Cl- from serosal and luminal solution, both in stimulated and inhibited tissues. The presence of Cl- in the luminal solution prevented this rise in pHi, an effect abolished by serosal 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS, 3 x 10(-4) M) but not by serosal amiloride (10(-3)M). In the presence of serosal Cl-, pH(i) increased after exposure to serosal DIDS, more prominently in the stimulated than in the inhibited tissues. These results confirm the presence of a Cl(-)-HCO3-exchanger in the basolateral membrane of oxynticopeptic cells in intact sheets of mucosa and suggest that luminal Cl- contributes to the regulation of pH(i) in oxynticopeptic cells.

Cardiac pheochromocytoma originating in the interatrial septum

A 36-year-old woman with classic clinical and biochemical features of pheochromocytoma was found to have a cardiac pheochromocytoma originating in the interatrial septum and a significant obstructive lesion in the left anterior descending coronary artery. Complete resection of the pheochromocytoma and an aortosaphenous vein graft were performed. This is the first reported case of successful resection of an interatrial pheochromocytoma.

Transfusion-transmitted HTLV-I/II infection in patients undergoing open-heart surgery

Sera from 5,244 blood donations collected between 1979 and 1987 were screened for antibody to HTLV-I with an enzyme immunoassay (EIA) whose result was confirmed with a two-step procedure including Western blot (WB) and radio immunoprecipitation. Of 20 repeatedly reactive samples, two were confirmed positive for HTLV-I infection. These blood units were transfused to patients undergoing cardiac surgery. Both recipients of the confirmed anti-HTLV-I positive units were infected with HTLV-I as evidenced by antibody seroconversion. In contrast, six recipients of EIA positive, WB indeterminate blood and nine recipients WB negative blood were not infected with HTLV-I. These results confirm a low prevalence of HTLV-I infection in US blood donors, the capacity of infected units to transmit the virus to recipients, and the importance of an appropriate confirmatory assay.

[Experimental control study of fasciolopsiasis in Taiwan]

This study was conducted from March 1985 to September 1987 among the pupils of Chung-Ying Primary School of Hsia-Ying township in Tainan Country, Southern Taiwan. Health education revealed the preferred control method against Fasciolopsis infection in this study. The education method included lectures, demonstrations of parasites and home visits at regular intervals. The subjects included the staff and children of the school and all family members. At the same time, the children infected with Fasciolopsis were treated with praziquantel in June, 1986. Fecal material of the all primary school children of Hsia-Ying township was examined with the antiformin-ether concentration method. One year before control the positive rate of Fasciolopsis was 25.1%. One year after control in March 1986, it was decreased to 9.5%. Two and a half years after control in September 1987, it was farther brought down to 1.0%. The x2-test of positive rate showed statistically different. Health education with medication is recommended for the control of fasciolopsiasis.

Presence of catenated human papillomavirus type 16 episomes in a cervical carcinoma cell line

Human papillomavirus (HPV) is frequently associated with cervical carcinoma and derived cell lines. In primary tissues of the carcinoma, the viral genome may be present in episomal or integrated configuration. In cell lines, however, only integrated HPV sequences have been reported. In this article, we describe the presence of episomal type 16 HPV (HPV16), demonstrated by electron microscopy and two-dimensional agarose gel electrophoresis, in a cervical carcinoma cell line, CC7T/VGH, established in 1980 in Taiwan. In CC7T/VGH, the HPV16 sequences are transcriptionally active, and at least three major HPV16 RNA species were detected in Northern blots. Results from restriction enzyme and S1 nuclease analysis suggest a composition of oligomeric HPV16 molecules in dimeric repeats. In addition, the HPV16 oligomers exist as catenated molecules of interlocking rings instead of concatemers. A monomeric copy of the HPV16 episome was cloned from a Hirt supernatant of CC7T/VGH by using a plasmid vector. Mapping and partial sequencing studies revealed an internal deletion of 163 base pairs within the L1 open reading frame. However, insertion of an A.C nucleotide pair at the deletion junction restored the otherwise frame-shifted L1 open reading frame. Two base transitions were also found within the E7 and the E1 open reading frames. Our findings suggest the need for closer examination for HPV episomal catenation in other cervical carcinoma cell lines as well as in primary carcinoma tissues of the uterine cervix and the anogenital tract. With CC7T/VGH, a way is now available for studies of many important aspects of the biology of HPV such as replication and gene expression of the extrachromosomal viral genome.

Zinc absorption in human small intestine

We determined the intestinal site of zinc absorption in humans and investigated the interaction between intestinal absorption of zinc and other solutes using the triple-lumen steady-state perfusion technique. Twenty-one healthy subjects participated in the study. During intestinal perfusion of a balanced electrolyte solution containing 0.1 mM zinc acetate, zinc absorption occurred throughout the entire small intestine. However, the jejunum had the highest rate of absorption (357 +/- 14 nM.min-1.40 cm-1) compared with the duodenum (230 +/- 33 nM.min-1.40 cm-1) and ileum (84 +/- 10 nM.min-1.40 cm-1). Over a range of zinc concentrations infused into the jejunum (0.1, 0.9, and 1.8 mM) there were linear increases in the rate of zinc absorption (P less than 0.05). Intestinal absorption of zinc was significantly stimulated by the addition of glucose (20 mM). Zinc absorption increased from 459 +/- 39 to 582 +/- 45 nM.min-1.40 cm-1 (P less than 0.05). Conversely, zinc (0.9 mM) also enhanced the absorption of glucose, which was increased from 293 +/- 43 to 447 +/- 27 microM.min-1.40 cm-1 (P less than 0.05). The enhanced absorption of zinc or glucose was not accompanied by any increase in absorption of water and sodium. In contrast, increasing the concentration of zinc in the perfusate resulted in decreased absorption of sodium and water in a dose-related manner. In conclusion, our study demonstrated that zinc absorption is concentration dependent and occurs throughout the small intestine. The jejunum has the highest rate of absorption of zinc. The interactions between absorption of zinc and other solutes suggest that the transport process of zinc is carrier mediated.

Amniotic fluid thymosin alpha 1 levels increase during gestation

Thymosin alpha 1 is one of several cytokines produced by the thymus that modulates immune function. The presence of elevated serum levels of thymosin alpha 1 in pregnant women and their newborns has suggested that this peptide may play a role in perinatal immunology. In this investigation, we used a microenzyme-linked immunosorbent assay to assay amniotic fluid for immunoreactive thymosin alpha 1 and found levels that were remarkably higher than newborn serum levels (P less than 10(-4]. The increase of thymosin alpha 1 in amniotic fluid with fetal age was natural logarithmic (r = 0.838, P less than 10(-6]. Thymosin alpha 1 in amniotic fluid may account for some of the immunologic properties of this medium.

Sequence duplication and internal deletion in the integrated human papillomavirus type 16 genome cloned from a cervical carcinoma

Integrated human papillomavirus type 16 (HPV16) sequences were cloned from a cervical carcinoma and analyzed by restriction mapping and nucleotide sequencing. The viral integration sites were mapped within the E1 and E2 open reading frames (ORFs). The E4 and E5 ORFs were entirely deleted. An internal deletion of 376 base pairs (bp) was found disrupting the L1 and L2 ORFs. Sequencing analysis showed that an AGATGT/ACATCT inverted repeat marked the deletion junction with two flanking direct repeats 14 and 8 bp in length. A 1,330-bp sequence duplication containing the long control region (LCR) and the E6 and E7 ORFs was also found. The duplication junction was formed by two 24-bp direct repeats with 79% (19 of 24) homology located within the LCR and the E2 ORF of the prototype viral genome, respectively. This observation leads us to propose that the initial viral integration involved an HPV16 dimer in which the direct repeats in tandem units recombined, resulting in reiteration of only a portion of the original duplication. A guanosine insertion between nucleotides 1137 and 1138 created a continuous E1 ORF which was previously shown to be disrupted. Results from this study indicate that sequence reiteration and internal deletion in the integrated, and possibly in the episomal, HPV16 genome are influenced by specific nucleotide sequences in the viral genome. Moreover, reiteration of the LCR/E6/E7 sequences further supports the hypothesis that the E6/E7 ORFs may code for oncogenic proteins and that regulatory signals in the LCR may play a role in cellular transformation.

Analogs of cell surface carbohydrates. Synthesis of D-galactose derivatives having an ethynyl, vinyl or epoxy residue at C-5

Compounds derived from D-galactose having an ethynyl, vinyl, or epoxide residue at C-5, as well as 7,7-dibromo olefinic, isomeric 7,7-gem-bromofluoro olefinic, and 6,6-gem-difluoro derivatives were obtained from 1,2:3,4-di-O-iso-propylidene-alpha-D-galacto-hexodialdo-1,5- pyranose.

Defective in vitro gamma interferon production and elevated serum immunoreactive thymosin beta 4 levels in patients with inflammatory bowel disease

Gamma interferon (IFN-gamma) production by peripheral blood mononuclear cells (PBM) was measured in 21 patients with Crohn's disease, in 15 patients with ulcerative colitis, in 12 patients with non-IBD gastrointestinal disease (disease control), and in 28 healthy controls. T-cell subset proportions and serum levels of thymosin alpha 1 and thymosin beta 4, two hormonelike thymic peptides, were also determined. No differences were seen in T-cell subset proportions in patients with Crohn's disease or ulcerative colitis when compared to healthy controls or to the disease-control group. In vitro IFN-gamma production was markedly decreased in Crohn's disease and in untreated, but not treated, patients with ulcerative colitis. Preincubation of PBM prior to the addition of inducer mitogen resulted in enhanced IFN-gamma production in patients with Crohn's disease or ulcerative colitis which significantly exceeded that seen either in healthy controls or in the disease-control group. Serum thymosin alpha 1 levels were comparable in all study groups; however, serum thymosin beta 4 concentrations were significantly higher in all patient groups than in the healthy controls. These results confirm a defective in vitro IFN-gamma production in patients with IBD which is apparently independent of endocrine thymus regulation.

Imparied lymphocyte proliferative response to mitogen in alcoholic patients. Absence of a relation to liver disease activity

Concanavalin A-induced lymphocyte proliferation was studied in 25 patients with alcoholic hepatitis or compensated alcoholic cirrhosis. Nine alcoholics without evidence of liver disease were also evaluated. A nonlinear correlation equation, which was natural logarithmic, was applied to individual dose-response proliferation curves and permitted comparisons between patient groups and controls. The proliferative response in all patient groups was significantly lower when compared to healthy controls and was independent of the presence or absence of liver disease. This suggests that some changes in immune function observed in alcoholics may be linked to the direct effects of alcohol on the immune system rather than to the associated liver disease.

Molecular analysis of hemoglobin H disease in Taiwan

The molecular basis of seven Chinese patients in Taiwan with hemoglobin H disease was investigated and was found to be heterogeneous in the mutation type. They were alpha-thalassemia-1 mutation combined with hemoglobin Constant Spring, an undetermined nondeletion form of alpha-thalassemia and a deletion form of alpha-thalassemia-2 mutations. The alpha-thalassemia-1 mutation was shown to be the --SEA type I haplotype.

Antibodies to Epstein-Barr virus-specific DNase in patients with nasopharyngeal carcinoma and control groups

Serum samples from 154 patients with nasopharyngeal carcinoma (NPC), 374 with other cancers, 1,000 normal controls from Government Employees' Clinic Center (GECC), and 3,642 individuals of various ethnic-dialect groups living in high-risk areas for NPC were collected and the concentration of antibodies to Epstein-Barr virus (EBV)-specific DNase activity was determined. Taking a serum sample where 1 ml will neutralize two or more units of the DNase activity as positive, 2-4 units as low level, 4-6 units as medium level, and more than 6 units as a high level of antibody, 90.3% of the NPC patients contained significant amounts of antibodies to EBV-specific DNase activity and most of those had high levels of the antibody. In contrast, only 11% of sera from patients with cancers other than NPC contained antibodies to EBV-specific DNase activity, and high levels were very rare (2.1%). The difference in positive rates between these two groups is highly significant according to the chi 2 test (P less than 0.001). The positive rate of this antibody in the control group (GECC) was 5.3% with 0.0%, 0.8%, and 4.5% having high, medium, and low levels of antibodies, respectively. Again, the difference in positive rates between the GECC group and the NPC group is statistically significant (P less than 0.001). Taken separately, the positive rates of anti-EBV DNase activity in the three high-risk groups were 11.7%, 13.0%, and 13.1%. No significant difference in age distribution for the levels of this antibody was observed in the control GECC group or the three high-risk groups. However, the positive rates of the three high-risk groups are more than twice those of the GECC group (11.7% approximately 13.1% vs 5.3%). This ratio coincides with the ratio of the probability of developing NPC in high-risk groups compared to that of the GECC group (also more than two times). The significance of this coincidence is discussed.

Early diagnosis of spontaneous bacterial peritonitis: values of ascitic fluid variables

In a search for clinical and laboratory factors that would aid in early diagnosis of spontaneous bacterial peritonitis, we identified two groups of patients with chronic liver disease and ascites: 1) 38 patients with 40 episodes of spontaneous bacterial peritonitis, and 2) 39 randomly selected patients with 40 sterile paracenteses who were matched for severity of liver dysfunction as a reference group. A variety of clinical and laboratory features were examined. The absolute lymphocyte count in peripheral blood was lower for the spontaneous bacterial peritonitis group (mean = 703/mm3 vs. 1,212/mm3, p less than 0.005). Four ascitic fluid variables, i.e., a white blood cell count of greater than or equal to 300/mm3, a polymorphonuclear leukocyte count of greater than or equal to 240/mm3, an ascitic fluid/serum LDH ratio of greater than or equal to 0.4, or an ascitic fluid/serum glucose ratio of less than or equal to 1.0, could separate the spontaneous bacterial peritonitis and reference groups with both sensitivity and specificity of greater than 70%. Although ascitic fluid total leucocyte and polymorphonuclear leucocyte counts are appropriate indicators for the early diagnosis of spontaneous bacterial peritonitis, the possibility of their false positivity should be warranted. The use of multiple tests including ascitic fluid/serum LDH and glucose ratios has better positive predictive value than a single test alone.

Quantitative analysis of mitogen-stimulated cellular proliferation: effect of concanavalin A and thymosin interaction

Studies of mitogen stimulated lymphocyte proliferation have shown that considerable variation exists in the magnitude of response to specific mitogens. No standard method has been devised which would permit comparisons of the non-linear proliferation response between groups. In this study a mathematical correlation between mitogen stimulation and cellular response is defined using concanavalin A as the mitogen. A logistic equation was derived by least sum of squares regression analysis. The dose response relationship of concanavalin A stimulated peripheral blood mononuclear cell proliferation was natural logarithmic. A computing program was designed to accomodate any calculation related to proliferation assays. The efficacy of this program and the adequacy of the equation were confirmed after they were tested in thymosin fraction 5 treated cellular proliferation experiments. This study demonstrates a quantitative method for the comparisons of immunological proliferation response among groups.

Characteristics of melanosis duodeni: incorporation of endoscopy, pathology, and etiology

Endoscopic features and analytical electron microscopic studies in a case of melanosis duodeni are reported. The pigment in the microphages is confirmed as being iron sulfide. The etiology of this unusual endoscopic presentation is hypothesized.

Transcholecystic endoscopic choledocholithotripsy: successful management of retained common bile duct stone

Removal of large common bile duct stones has been a continuing challenge. The feasibility and efficacy of transcholecystic endoscopic choledocholithotripsy in a high-risk patient are demonstrated in this report. The procedure requires an established cholecystostomy track, catheter dilatation of the cystic duct, and the application of electrohydraulic shock waves to the calculus. The use of a choledochofiberscope permits the passage of the electrohydraulic probe and minimizes complications by direct monitoring. Stone fragments are removed by basket retrieval. This procedure in conjunction with minicholecystostomy may obviate the need for surgery in selected high-risk patients with combined gallbladder and common bile duct stones.

Characterization of four monoclonal antibodies to factor VIII coagulant protein and their use in immunopurification of factor VIII

Four monoclonal anti-VIII:C antibodies were obtained from the fusion of the splenocytes of one Balb/C mouse with a specific activity ranging from 2.3 to 45,000 U/mg when purified from ascitic fluid. Only one antibody was able to inhibit completely Factor VIII:C in normal plasma. The four antibodies could bind Factor VIII:CAg in plasma and commercial concentrate both in liquid and solid phase, and were suitable for immunopurification of Factor VIII:C. Three antibodies competed with polyclonal anti-VIII:CAg Fab' in a liquid phase IRMA, and all of them were able to displace their own binding to Factor VIII:CAg. Competition studies between monoclonal antibodies for the binding to Factor VIII:CAg were performed and showed the recognition of different epitopes and various functional impact. These studies indicate that at least one antibody, with the lowest anti-VIII:C titer clearly recognizes a different epitope of VIII:C than those recognized by the others. Affinity constants ranged from 10(9) to 10(10) l/mole.

Effect of vector type, host strains and transcription terminator on heterologous gene expression in yeast

Using the surface antigen gene of the hepatitis B virus, and the promoter and terminator sequences of the yeast pho5 gene as a model system, a series of closely related expression plasmids were constructed to investigate the effect of vector type, genetic background of host strains and the presence of transcription terminator on the expression of heterologous gene in yeast. Plasmids carrying the replication origin of the 2 mu plasmids were found to be much more stable than those either independently or simultaneously carrying ars1 sequences. Gene expression was also higher with 2 micron-based plasmids. Yeast selection marker (trp1 or leu2) and therefore the host strains used did not have significant effects on gene expression. Addition of transcription terminator sequences downstream to the HBsAg gene also contributed only limited increases in gene expression levels.