Synthesis and antiviral activity of fluoro-substituted apio dideoxynucleosides

Novel fluoro-substituted apio dideoxynucleosides ((+/-)-3a and (+/-)-3b) were efficiently synthesized starting from 1,3-dihydroxyacetone via Horner-Emmons olefination as a key step. Cyclization of fluoro ester (+/-)-6 under acidic conditions to the fluorolactone was smoothly proceeded in favor of trans-fluorolactone due to the favorable transition state with equatorial hydroxymethyl substituent. Unfortunately, the final nucleosides (+/-)-3a and (+/-)-3b were found to be inactive against several viruses such as HIV-1, HSV-1, HSV-2 and HCMV.

Structure-activity relationships of apio nucleosides as potential antiviral agents

Several types of novel apio nucleosides were synthesized starting from 1,3-dihydroxyacetone and evaluated for antiviral activity. Among compounds tested, amino substituted apio dideoxynucleosides exhibited anti-HBV activity, while thioapio dideoxynucleosides were found to be active against HIV-1. Apio dideoxydidehydro nucleosides showed moderate to potent anti-HCMV activity, but their bioisosteric thioapio dideoxydidehydro nucleosides did not exhibit any significant antiviral activity.

Synthesis and antiviral activity of D- and L-2'-azido-2',3'-dideoxy-4'-thiopyrimidine and purine nucleosides

Novel D- and L-2'-azido-2',3'-dideoxy-4'-thionucleosides were synthesized starting from L- and D-xylose via D- and L-4-thioarabitol derivative as key intermediates and evaluated for antiviral activity, respectively. When the final nucleosides were tested against HIV-1, HSV-1, HSV-2, and HCMV, they were found to be only active against HCMV without cytotoxicity up to 100 micrograms/ml.

Syntheses and structure--activity relationships of novel apio and thioapio dideoxydidehydronucleosides as anti-HCMV agents

On the basis of the fact that apio dideoxynucleosides, in which the furanose oxygen and the C2 of the 2,3-dideoxyribose are transposed, exhibited potent anti-HIV activity and 2',3'-dideoxy-2',3'-didehydronucleosides also showed potent anti-HIV activity, we synthesized apio dideoxydidehydronucleosides in which the oxygen atom and the double bond of the 2,3-dideoxy-2,3-didehydroribose are exchanged. The thioapio dideoxydidehydronucleosides were also synthesized since sulfur serves as a bioisostere of oxygen. Apio dideoxydidehydronucleosides 13a--f were synthesized starting from 1,3-dihydroxyacetone, utilizing phenylselenenyl chemistry as a key step. The ratio of the anomeric mixture was variable from 1:1 to 5:1 during the condensation of nucleosidic bases with the phenylselenyl acetate 11 in the presence of a Lewis acid. This is in contrast with other glycosyl donors such as 5-O-(tert-butyldiphenylsilyl)-2-phenylselenenyl-2,3-dideoxyribosyl acetate which shows excellent neighboring group effect (alpha:beta = 1:99). Thioapio dideoxydidehydronucleosides 22a,b were synthesized from the lactone 9 via thiolactone 17 as a key intermediate which was synthesized from dicyclohexylcarbodiimide coupling of the mercapto acid produced from the basic hydrolysis of thioacetate 16. The majority of apio analogues synthesized in this study exhibited moderate to potent anti-HCMV activity, among which the 5-fluorouracil derivative 13c was found to be the most potent against HCMV, while thioapio analogues showed no activity against HCMV. However, all synthesized compounds did not exhibit any significant activities against HIV-1, HSV-1, and HSV-2. The fact that apio dideoxydidehydronucleosides were active against HCMV suggests that the apio dideoxydidehydro sugar moiety can serve as a novel template for the development of new antiviral agents.

Synthesis and antiviral activity of novel D- and L-2'-azido-2',3'-dideoxyribofuranosyl-4'-thiopyrimidines and purines

Novel D- and L-2'-azido-2',3'-dideoxyribofuranosyl-4'-thiopyrimidines and purines have been synthesized starting from L-xylose and D-xylose, respectively. Among synthesized compounds tested against several viruses such as HIV-1, HSV-1, HSV-2, and HCMV, D-beta-N6-methyladenine (ent-22a) and D-alpha-N6-methyladenine (ent-22b) analogues were found to exhibit significant anti-HCMV activity.

Purinoceptor-mediated calcium mobilization and proliferation in HaCaT keratinocytes

To investigate the effect of nucleotides on cytosolic free calcium mobilization and proliferation activity in HaCaT keratinocytes, nucleotides-induced intracellular free calcium concentration ([Ca(2+)](i)) and cell proliferation observed. [Ca(2+)](i) to the extracellular nucleotides was determined using Ca(2+) sensitive indicator, Fura-2/AM with digital video fluorescence imaging microscopy, and cell proliferation was evaluated by counting of cell number. An adenosine 5'-triphosphate (ATP)-induced [Ca(2+)](i) increase was observed from the concentration of 10(-8) M and was more conspicuous at higher concentrations in a concentration-dependent manner. Additionally, other nucleotides such as ADP, UTP, and 2-me-S-ATP also induced a [Ca(2+)](i) increase in a concentration-dependent manner. However, adenosine induced a slight increase of [Ca(2+)](i) only at 10(-3) M. alpha,-methylene-ATP did not evoke any rise in [Ca(2+)](i). The maximal response observed occurred with ATP and UTP at a concentration of 10(-4) M. The ATP-induced transient [Ca(2+)](i) increase was attenuated by the pretreatment with phospholipase C (PLC) inhibitor, U-73122 (10 microM) for 30 min. ATP-induced [Ca(2+)](i) increase and cell proliferation were inhibited by putative P2Y receptor antagonist, suramin (10(-4) M). When the HaCaT cells were stimulated with nucleotides on a concentration of 10(-4) M and cultured for 5 days, the order of effect on cell proliferation was observed to be ATP>UTP>ADP>2-me-S-ATP. Based on these results, we suggest that extracellular ATP stimulate HaCaT keratinocytes proliferation via purinoceptor-mediated [Ca(2+)](i) mobilization

Transplantation of peripheral blood stem cells mobilized by intensified consolidation and granulocyte colony-stimulating factor in acute leukemia

The purpose of this study was to evaluate the feasibility and efficacy of autologous transplantation of peripheral blood stem cells (PBSC) mobilized with high-dose consolidation chemotherapy and granulocyte colony-stimulating factor in patients with acute myelogenous leukemia (AML). Twenty patients received myeloablative chemotherapy or chemo-radiotherapy including total body irradiation followed by the infusion of PBSC. PBSC were collected by large-volume leukaphereses. The mean number of mononuclear cells and CD34-positive cells infused were 7.2 x 10(8)/kg (range, 2.2-16.6), and 6.6 x 106/kg (range, 2.1-27.7), respectively. Engraftment failure was not seen in the enrolled patients. The median time to neutrophil (> or = 500/microL) and platelet recovery (> or = 50,000/microL) from the transplant was 12 days (range, 8-20) and 28 days (range, 10-600), respectively. The 2-year probability of disease-free survival (DFS) and relapse were 43% and 57% for patients with AML transplanted in first complete remission (CR1). The outcome of the patients transplanted in the advanced status was significantly worse than the patients transplanted in CR1 (P=0.04). Most relapses occurred within 1 year after transplantation. Fatal hepatic veno-occlusive disease was observed in one case. Other transplantation-related toxicities were mild. Our results demonstrated that autologous transplantation of high-dose consolidation chemotherapy-mobilized peripheral blood progenitor cells is feasible in the patients with AML in CR1. To further reduce the risk of leukemia relapse, much effort should be contributed to the field of ex vivo purging and post-transplant immunotherapy.

Retention of alkamides in dried Echinacea purpurea

Different drying methods, such as freeze-drying (FD), vacuum microwave drying (VMD), and air-drying (AD), were applied to fresh roots and leaves of Canadian-grown Echinacea purpurea to determine the optimal method for preserving alkamide levels. Using HPLC, six alkamide fractions (alkamides 1, 2, 3, 6a/6, 7, 8/9) were quantitated in dried roots, whereas four alkamide fractions (alkamides 1, 2, 3, 8/9) were measured in dried leaves. Different elution conditions used in HPLC for alkamide analysis did not affect the eluted fractions nor the quantitation of different alkamides. Individual alkamide concentrations in roots and leaves were affected by the drying methods used. To preserve higher levels of total alkamides, FD was found to be the best method, VMD was a superior method for drying roots than AD at 70 degrees C, while AD at 50 degrees C was the preferred method for drying leaves of E. purpurea.

Retention of caffeic acid derivatives in dried Echinacea purpurea

Different drying methods were applied to fresh Canadian-grown Echinacea purpurea flowers to determine optimal drying procedures for preserving caffeic acid derivatives. Fresh flowers of E. purpurea were dried by freeze-drying (FD), vacuum microwave drying with full vacuum (VMD), and air-drying (AD) at 25, 40, and 70 degrees C. Using HPLC, chicoric acid and caftaric acid levels were quantitated in dried flowers. These acids were significantly affected by the drying method conditions used. Although significant (p < 0.05) loss of chicoric acid was observed when flowers were stored at high moisture, VMD flowers with a low moisture content retained the highest levels of chicoric acid and caftaric acid similar to FD flowers. Flowers that were AD at 25 degrees C retained about 50%, while those dried by AD at 70 degrees C resulted in the lowest retention of these acids. Although flowers dried by AD at 40 degrees C retained relatively high amounts of chicoric acid and caftaric acid, the time (55 h) required to reach optimal drying was considerably longer than that (47 min) for VMD.

Serum immunoreactivity to S-100 in children with cerebral palsy and delayed development and in their healthy parents

The passive immunization of pregnant female rats to S-100 protein often leads to ultra-structural abnormalities in the brain glial structures of the offspring of these rats and induces signs of delayed development in the fetal brain. Additionally passive immunization of pregnant animals with certain antigens induces permanent Ag-specific changes in the immune response of their offspring. The purpose of this study was to investigate serum immunoreactiviy (SIR) to S-100 in cerebral-palsied and developmentally-delayed children as well as in their healthy parents and to evaluate its significance related to radiologic findings of brain MRI and single photon emission computed tomography (SPECT). The subjects were children with cerebral palsy and delayed development that had abnormal findings on brain MRI or Brain SPECT. SIR to S-100 protein was measured by ELISA method in the patients, their healthy parents, 20 normal adult controls and 22 normally developed children. The SIR to S-100 protein was significantly higher in the cerebral-palsied and developmentally-delayed children when compared to that of the normal control group children. Increased SIRs were detected in healthy mothers but not in their fathers. There was no difference of SIR between the cerebral-palsied and developmentally-delayed children or any significant difference of SIRs according to the findings of the brain MRI or to developmental quotients. But, the SIRs to S-100 protein were higher in the group of more abnormal findings on brain SPECT.

Clinical improvement and immunohistochemical findings in severe atopic dermatitis treated with interferon gamma

BACKGROUND

Several clinical studies have focused on the therapeutic effects of interferon gamma (IFN-gamma) in patients with severe atopic dermatitis (AD), although the dosage of recombinant IFN-gamma (rIFN-gamma), therapeutic schedule, and the degree of clinical improvement were different among studies. Although the exact mechanism of action of IFN-gamma therapy in AD is not clear, the beneficial effects of IFN-gamma have been attributed mainly to an immunomodulating effect on the expression of certain immunologic markers.

OBJECTIVE

Our purpose was to study the therapeutic effect of two different dosages of rIFN-gamma on AD and to investigate the change of lesional expression of infiltrating inflammatory cell markers associated with rIFN-gamma therapeutic efficacy.

METHODS

Fifty-one patients with severe recalcitrant AD were treated with rIFN-gamma. Twenty patients were treated with 0.5 x 10(6) IU/m(2) of rIFN-gamma (low-dose [LD] group); 21 patients received 1.5 x 10(6) IU/m(2) of rIFN-gamma (high-dose [HD] group); and 10 patients received placebo. The patients were injected subcutaneously 3 times a week for 12 weeks. Immunohistochemical study was performed in 20 patients of the HD group in the initial visit and after completion of rIFN-gamma therapy with a panel of 14 monoclonal antibodies as markers of inflammatory cells and cytokines.

RESULTS

The disease severity of the 2 groups treated with rIFN-gamma was reduced significantly at the end of treatment compared with that of the placebo group (P<.05). More rapid clinical improvement and more effective treatment outcome were seen in the HD group than in the LD group for the initial 6-week treatment period; however, the clinical improvement in both of the treated groups was stable and maintained after week 8 of treatment. Immunohistochemical findings showed statistically significant reduction in the lesional expression of CD25 and EG2 cells that infiltrated into skin after rIFN-gamma therapy.

CONCLUSION

This study demonstrated that rIFN-gamma therapy for AD is safe and effective. In the early phase of therapy, a higher dosage of rIFN-gamma is more effective; and for the maintenance of clinical improvement, a lower dosage of rIFN-gamma is recommended when high cost and effectiveness of rIFN-gamma are considered. The therapeutic efficacy of rIFN-gamma in AD might be in part related to the decreased number of CD25(+) and EG2(+) inflammatory cells infiltrated into skin.

A merger of rational drug design and combinatorial chemistry: development and application of peptide secondary structure mimetics

Recent efforts toward the development of peptide secondary structure mimetics at Molecumetics Ltd. for the discoveries of new drug candidates utilizing combinatorial chemistry with solid phase synthesis are described.

Androgen receptor gene mutation identified by PCR-SSCP and sequencing in 4 patients with complete androgen insensitivity syndrome

To study the genetic defect of the human androgen receptor (hAR) gene in the complete androgen insensitivity syndrome (CAIS), we amplified each of the eight exons by PCR in genomic DNA extracted from the paraffin blocks of the resected gonads. We analyzed using SSCP, and directly sequenced the abnormally shifted bands. Mutations were found in 4 cases of CAIS. Patient 1 carried a point mutation; a G to A transition in exon 7 resulted in a change from arginine to glutamine at codon 831. Patient 2 carried a point mutation; a C to T transition in exon 7 resulted in a change from arginine to stop at codon 831. Patient 3 carried a point mutation and deletion in exon 7. A point mutation was an A to G transition that caused a glutamine to be substituted for the asparagine present at codon 819. A deletion of a G at codon 820 resulted in a frameshift and consequently in the introduction of a premature stop at codon 821. Patient 4 carried a mutation in 5' splice donor site of intron 7; a G to T transition might have caused an abnormal splicing of the exon 7. All of the mutations were found in exon 7. These mutations of hAR gene might be related to the pathogenesis of CAIS.

Hydroxyoxazolidines as alpha-aminoacetaldehye equivalents: novel inhibitors of calpain

The synthesis of [1-[(5-hydroxy-4-(phenylmethyl)-3-oxazolidinyl)carbonyl]-2-ethylpropy lcarbamic acid phenylmethyl ester (2; MDL 104,903), a potent inhibitor of calpain, is described. Synthesis of related compounds, which offer insights into the mechanism of action for 2, are also described, as is an O-acetyl prodrug derivative of 2.

A case of cutaneous endometriosis developed in postmenopausal woman receiving hormonal replacement

Cutaneous endometriosis is characterized by the presence of extrauterine endometrial tissue in or under the skin. We report a case of cutaneous endometriosis in postmenopausal woman who was receiving hormonal replacement.

Head and neck dermatitis: the role of Malassezia furfur, topical steroid use and environmental factors in its causation

The aetiology of head and neck dermatitis (HND), one subgroup of postpubertal atopic dermatitis (AD), is still unclear. The aim of this study was to evaluate the influence on HND of common environmental factors, long-term topical steroid use, and the role of Malassezia furfur infection. Relevant information was obtained from 100 patients with HND attending our dermatology clinic by means of both physical examinations and questionnaires. Corticosteroid-induced vasoconstriction was estimated by visual scoring of laser-Doppler flowmetry. and the following immunological studies were performed: skin prick test, measurement of total IgE, eosinophil cationic protein, and specific IgE antibodies to several fungal antigens including those of M. furfur. The questionnaire revealed that sweating (81%), heat (71%), dryness (70%), psychic stress (67%), and sun exposure (50%) were responsible for aggravation of skin lesions. The vascular response to topical steroid was reduced in HND patients as compared with that of normal healthy controls (P < 0.05). Fifty-four of 80 patients with HND (68%) had anti M. furfur-specific IgE antibodies and 36 of 80 patients (45%) showed positive skin prick tests for M. furfur. The clinical severity and serum total IgE of HND patients were higher in patients with positive response to anti-M. furfur-specific IgE antibodies than in patients with negative response (P < 0.05). These results suggest that HND can be aggravated not only by M. furfur but also by environmental factors such as sweating, heat, dryness, psychic stress and sun exposure. Furthermore, long-term use of topical steroid might be associated with the development of diffuse erythematous lesions with telangiectasia on the head and neck areas.

Secondary structure peptide mimetics: design, synthesis, and evaluation of beta-strand mimetic thrombin inhibitors

Constrained dipeptide mimetic templates were designed to mimic the secondary structure of peptides in a beta-strand conformation. Two templates corresponding to the D-Phe-Pro portion of the thrombin inhibitor D-Phe-Pro-ArgCH2Cl were synthesized and converted into nine alpha-ketoamide and alpha-ketoheterocycle inhibitors of thrombin. Additionally, a template corresponding to L-Phe-Pro was synthesized and converted to a thrombin inhibitor. The in vitro inhibition of thrombin by these compounds was determined, and those corresponding to the D-Phe-Pro were found to be more potent inhibitors than the L-Phe-Pro mimetic. The alpha-ketoamides were found to be more potent than the alpha-ketoheterocycles but had much slower on rates. By comparison of a series of alpha-ketoamide analogues, it is apparent that the there is a preference for binding of bulky hydrophobic substituents in the P' portion of the thrombin active site. Three of the inhibitors (MOL098, MOL144, and MOL174) were screened against a series of coagulation and anticoagulation enzymes and found to be selective for inhibition of the coagulation enzymes. Two of the inhibitors were tested in in vitro models of intestinal absorption and found to have low absorption potential. The compounds were then tested in vivo in both rats and primates, and one of them (MOL144) was approximately 25% absorbed in both species. This study has delineated the synthesis of constrained dipeptide beta-strand mimetics and validated the potential for compounds of this type as potent thrombin inhibitors and possible drug leads.

Reusability of avidin-biotinylated immunoglobulin Y columns in immunoaffinity chromatography

Reusability of avidin-biotinylated IgY columns for immunoaffinity chromatography was examined by repeated use and regeneration. An enzyme-linked immunosorbent assay-elution assay using CovaLink NH microtiter plates was used to find the optimal conditions for regeneration of columns. Actigel avidin-biotinylated IgY column retained about 90% of its initial IgG binding capacity after 50 cycles, with 0.1 M glycine-HCl buffer, pH 2.8, as eluent, requiring no regeneration. However, IgG binding capacity of UltraLink avidin-biotinylated IgY column gradually decreased to 75 and 65% after 10 and 20 cycles, respectively, with the commercial eluent, Actisep. Results from the CovaLink NH system agreed with those from UltraLink avidin-biotinylated IgY columns. The UltraLink avidin-biotinylated IgY column was regenerated twice, by applying 8 M guanidine-HCl, pH 1.6, to dissociate biotinylated IgY antibodies from the column. About 40 and 25% of IgG binding capacities remained after the first and second regeneration. By applying new biotinylated IgY to the treated columns, about 95 and 90% of the initial IgG binding capacity before any treatment were recovered. These results demonstrated that avidin-biotinylated IgY columns are reusable with or without regeneration depending on the avidin-immobilized matrix.

Ex vivo generation of functional dendritic cells from mobilized CD34+ hematopoietic stem cells

The ability to generate dendritic cells (DCs) in sizeable numbers has enormous implications for the development of clinically-effective antigen presentation procedures for cancer immunotherapy. We evaluated the generation of immunostimulatory DCs from peripheral blood CD34+ cells collected from healthy donors. CD34+ cells purified from leukapheresis product were seeded at 1 x 10(4) cells/mL in complete medium supplemented with GM-CSF, TNF alpha, IL-4, c-kit ligand, and flt3 ligand (FL). By day 14 of culture in the presence of GM-CSF + TNF alpha, the total cell number increased by 23.4 +/- 5.4-fold compared to the starting number of CD34+ cells. When the c-kit and FL were added to GM-CSF and TNF alpha, the cell number increased by 109.8 +/- 11.2-fold without affecting the immunophenotype of recovered cells. Flow cytometric analysis indicated that cells with the markers of mature dendritic cells, i.e., CD1a +CD14 -HLA-DR+, and CD80+CD86+HLA-DR+, constituted 49.0% +/- 7.5%, and 38.9% +/- 6.5%, respectively. This pattern of expression of surface antigen was unchanged whether the c-kit ligand and/or FL was added. The irradiated CD1a+HLA-DR+ cells recovered from in vitro cultures elicit a vigorous proliferation of allogeneic peripheral blood T-cells, irrespective of cytokine combinations. These findings provide advantageous tools for the large-scale generation of DCs that are potentially usable for clinical protocols of immunotherapy or vaccination in patients undergoing cancer treatment.

Inhibition of human neutrophil elastase. 4. Design, synthesis, X-ray crystallographic analysis, and structure-activity relationships for a series of P2-modified, orally active peptidyl pentafluoroethyl ketones

A series of P2-modified, orally active peptidic inhibitors of human neutrophil elastase (HNE) are reported. These pentafluoroethyl ketone-based inhibitors were designed using pentafluoroethyl ketone 1 as a model. Rational structural modifications were made at the P3, P2, and activating group (AG) portions of 1 based on structure-activity relationships (SAR) developed from in vitro (measured Ki) data and information provided by modeling studies that docked inhibitor 1 into the active site of HNE. The modeling-based design was corroborated with X-ray crystallographic analysis of the complex between 1 and porcine pancreatic elastase (PPE) and subsequently the complex between 1 and HNE.

Synthesis and antiviral activity of 2'-fluorohexopyranosyl nucleosides

2'-Fluorohexopyranosyl nucleosides 1a and 1b which contained a bioisosteric double bond and a fluorine were synthesized in 12 steps, starting from D-galactose. During diethylaminosulfur trifluoride (DAST) fluorination, retention of stereochemistry was observed through the participation of methoxy or chloro group at the 6-position of the purine base. The final nucleosides 1a and 1b were found to be inactive against HIV-1 and HSV-1,2.

p53 mutation and overexpression in hepatocellular carcinoma and dysplastic nodules in the liver

In hepatocarcinogenesis, both de novo and multistep pathways have been suggested and in the latter a dysplastic nodule is the proposed precancerous lesion. In this study, we tried to ascertain whether or not the p53 gene is altered in low-grade/high-grade dysplastic nodules (LDN/HDN) and to determine the role of p53 alteration in multistep hepatocarcinogenesis. Eight hepatocellular carcinomas (HCCs), 9 HDNs, 17 LDNs and 25 cirrhotic nodules (LCs) were examined by polymerase chain reaction-single strand conformation polymorphism/direct sequencing and immunohistochemical staining for p53. Four of the 8 HCCs (50%) revealed p53 overexpression and 2 (25%) had missense mutations. Four of the 9 HDNs (44%) showed weak and/or focal p53 overexpression but none had mutation in the exons examined. Neither p53 overexpression nor mutation was found in 17 LDNs and 25 LCs. These results suggest that p53 mutation might be an unusual event in precancerous lesions of multistep hepatocarcinogenesis (DN-HCC sequence) and may play a less crucial part than in colorectal carcinogenesis.

Genetic evidence for the multicentric origin of synchronous multiple gastric carcinoma

Multiple gastric cancers, which constitute 4% to 10% of all gastric cancers, occur in older people and are associated with more extensive intestinal metaplasia. With regard to the genesis of multiple gastric cancers, multicentricity (independent origin) rather than multifocality (local or lateral spread of one cancer) has been the favored theory. Conventional morphologic study, however, has not been able to provide convincing evidence in support of multicentricity. The purpose of this study was to verify the multicentric origin of multiple gastric cancers at a genetic level. For this purpose, immunohistochemical and molecular techniques were used to define the mutation pattern of APC, MCC and p53 in multiple lesions of synchronous multiple gastric cancers. The study was based on a total of 30 gastric tumors from 13 patients, including 10 double tumors, 2 triple tumors, and 1 quadruple tumor. Single-strand conformation polymorphism and polymerase chain reaction direct sequencing were carried out for exons 5 to 8 of p53, and loss of heterozygosity was detected on the basis of polymerase chain reaction amplification of polymorphism in exon 10 of MCC and in exon 11 of APC. Twelve of 13 cases showed alteration in one or more genetic markers. Of these, three demonstrated a discordant mutation pattern of p53 in individual lesions, and another two revealed allelic loss of MCC in one lesion and p53 mutation in the other. In six other cases, only one lesion showed alteration of APC, MCC, or p53, and in the remaining case, one lesion carried p53 and MCC mutations and the other carried MCC loss of heterozygosity only. The results of this study showed discordance of the mutation pattern of APC, MCC, and p53 in individual lesions of multiple gastric cancers, providing genetic evidence for a multicentric origin of synchronous multiple gastric carcinomas. Collectively, these findings supported the theory of field cancerization in gastric carcinogenesis.

Activation of hippocampal adenosine A3 receptors produces a desensitization of A1 receptor-mediated responses in rat hippocampus

The adenosine A3 receptor is expressed in brain, but the consequences of activation of this receptor on electrophysiological activity are unknown. We have characterized the actions of a selective adenosine A3 receptor agonist, 2-chloro-N6-(3-lodobenzyl)-adenosine-5'-N-methyluronamide (Cl-IB-MECA), and a selective A3 receptor antagonist, 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1, 4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS 1191), in brain slices from rat hippocampus. In the CA1 region, activation of A3 receptors had no direct effects on synaptically evoked excitatory responses, long-term potentiation, or synaptic facilitation. However, activation of A3 receptors with Cl-IB-MECA antagonized the adenosine A1 receptor-mediated inhibition of excitatory neurotransmission. The effects of Cl-IB-MECA were blocked by pretreatment with MRS 1191, which by itself had no effect on A1 receptor-mediated responses. The presynaptic inhibitory effects of baclofen and carbachol, mediated via GABA(B) and muscarinic receptors, respectively, were unaffected by Cl-IB-MECA. The maximal response to adenosine was unchanged, suggesting that the primary effect of Cl-IB-MECA was to reduce the affinity of adenosine for the receptor rather than to uncouple it. Similar effects could be demonstrated after brief superfusion with high concentrations of adenosine itself. Under normal conditions, endogenous adenosine in brain is unlikely to affect the sensitivity of A1 receptors via this mechanism. However, when brain concentrations of adenosine are elevated (e.g., during hypoxia, ischemia, or seizures), activation of A3 receptors and subsequent heterologous desensitization of A1 receptors could occur, which might limit the cerebroprotective effects of adenosine under these conditions.

Induction of apoptosis in HL-60 human promyelocytic leukemia cells by adenosine A(3) receptor agonists

The effects of adenosine (ADO) analogs on cells of the human promyelocytic HL-60 line were examined. ADO A(3) receptor agonists, N(6)-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide (IB-MECA, 30-60 microM) and 2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide (CI-IB-MECA, 10-30 microM) induced apoptotic cell death. In contrast, neither an A(1)/A(2) antagonist (XAC) nor other selective ADO receptor agonists (CPA, NECA and CGS21680) induced apoptosis at concentrations of <30 microM. Both IB-MECA and CI-IB-MECA significantly induced Ca(2+) release from intracellular Ca(2+) pools followed by Ca(2+) influx, suggesting the presence of phospholipase C-coupled ADO A(3) receptors on HL-60 cells. This was further supported by the presence of mRNA of ADO A3 receptor in the cells. These results suggest that activation of ADO A(3) receptors is responsible for the ADO-induced apoptosis in HL-60 cells and could be of potential therapeutic value in the treatment of leukemia.

G protein-dependent activation of phospholipase C by adenosine A3 receptors in rat brain

The recently cloned G protein-coupled adenosine A3 receptor has been proposed to play a role in the pathophysiology of cerebral ischemia. Because phospholipase C activation occurs as a very early response to brain ischemia, we evaluated the ability of A3- selective and nonselective adenosine analogues to elicit phosphoinositide hydrolysis. In myo-[3H]inositol-labeled rat striatal and hippocampal slices, A3 agonists stimulated formation of [3H]inositol phosphates in a concentration-dependent manner. In striatum, the potency order was 2-chloro-N6-(3-iodobenzyl)- adenosine-5'-N-methyluronamide > or = N6-(3-iodobenzyl)- adenosine-5'-N-methyluronamide >> N-methyl-1,3-di-n-butylxanthine-7-beta-D-ribofuronamide > or = 5'-N-ethylcarboxamidoadenosine > or = N6-2-(4-aminophenyl)-ethyladenosine > N6-(p-sulfophenyl)-adenosine = 1,3-dibutylxanthine-7- riboside, which is identical to the potency order in binding studies at cloned rat A3 receptors. Stimulation of phospholipase C activity was abolished by guanosine-5'-O-(2-thiodiphosphate), confirming the involvement of a G protein-coupled receptor. Activation of phospholipase C was higher in the striatum than in the hippocampus, consistent with A3 receptor densities. Stimulation of phospholipase C activity by adenosine analogues was only modestly antagonized by xanthine derivatives and at much higher concentrations than needed for blocking adenosine A1, A2A, and A2b receptors. In the presence of an A1/A2 antagonist, a selective A3 in rat striation. Thus, stimulation of phospholipase C activity agonist only weakly inhibited forskolin-stimulated adenylyl cyclase activity represents a principal transduction mechanism for A3 receptors in mammalian brain, and perhaps A3 receptor-mediated increases of inositol phosphates in the ischemic brain contribute to neurodegeneration by raising intracellular calcium levels.

Gene frequencies of the five major human platelet antigens in African American, white, and Korean populations

BACKGROUND

The study of the immunogenetics of the human platelet antigens is important to the improvement of diagnosis and genetic counseling and to the development of screening programs for women at risk of having babies with neonatal alloimmune thrombocytopenia. Description of the immunogenetics of the human platelet antigens in some racial groups has been incomplete.

STUDY DESIGN AND METHODS

A reverse dot blot technique employing polymerase chain reaction-amplified genomic DNA was applied in genotyping the five major human platelet antigens in the following populations: 100 African American and 100 white women admitted to the obstetric unit at Johns Hopkins Hospital (Baltimore, MD) and 100 inpatients at Yonsei University (Seoul, Korea).

RESULTS

The gene frequencies of HPA-2b (Koa) and HPA-5b (Bra) in African Americans were twice those in whites (African Americans: 0.18 and 0.21, respectively; whites: 0.09 and 0.11, respectively). There is a very low gene frequency of the HPA-1b (PIA2) allele in Koreans (0.005). No significant differences were found in the gene frequencies of the human platelet antigens in whites in this series and those in published European studies.

CONCLUSION

These studies indicate a higher potential risk for alloimmunization to HPA-2 (Ko) and HPA-5 (Br) antigens in African Americans than in whites. In addition, the low gene frequency of HPA-1b (PIA2) in African Americans and Koreans suggests that alloimmunization to HPA-1a (PIA1) would be very unusual in these populations. These data may provide the basis for planning neonatal alloimmune thrombocytopenia screening programs in certain ethnic populations.

Studies using immobilized platelet glycoproteins for detection of platelet alloantibodies

The utility of an enzyme linked immunoassay for the detection of platelet alloantibodies to isolated platelet glycoproteins employing commercially available monoclonal antibodies was studied. The authors established the usefulness of the assay for antibodies to platelet alloantigens (APAA) by testing its sensitivity and specificity under different conditions and using a variety of alloantibodies from patients with immune mediated thrombocytopenia. The authors were able to specifically detect a variety of antibodies to platelet alloantigens on different platelet glycoproteins. These antibodies had specificity for HPA-1a (PIA1), HPA-3 (Bak) and HPA-5 (Br). These results show that the APAA is easily adaptable for routine diagnostic testing in hospital laboratories using commercially available monoclonal antibodies and for the diagnosis of alloimmune mediated thrombocytopenic conditions.

Bcl-2 expression in neuroblastoma is differentially regulated by differentiation inducers

Neuroblastoma is characterized by differentiation in vivo and in vitro, and the process is known to be associated with changes in various gene expressions, among which is the bcl-2 gene whose major function may be potentially involved in the resistance to anticancer chemotherapy. We investigated the changing patterns of bcl-2 expression in neuroblastoma cell lines according to differentiation to assess whether the expression patterns can be differentially modulated by different types of differentiation inducers. Differentiation was induced in two neuroblastoma cell lines [SK-N-SH, SK-N-BE(2)] using all-trans-retinoic acid, gamma-interferon and EHS laminin, respectively. The levels of expression of bcl-2 were analysed before and after differentiation using immunoblotting and subsequent densitometry. The expression patterns of bcl-2 differed according to the type of differentiation inducers. Its expression increased when treated with retinoic acid and EHS laminin along with neuronal differentiation, while differentiation with gamma-interferon treatment was associated with decreased bcl-2 expression. Decreased expression of bcl-2 despite neuronal differentiation induced by gamma-interferon was thought to be important in that a certain differentiation pathway without increased drug resistance-related factor expression exists, which in turn has implications for the clinical application of gamma-interferon, combined with chemotherapy.

Structure-activity relationships of 9-alkyladenine and ribose-modified adenosine derivatives at rat A3 adenosine receptors

9-Alkyladenine derivatives and ribose-modified N6-benzyladenosine derivatives were synthesized in an effort to identify selective ligands for the rat A3 adenosine receptor and leads for the development of antagonists. The derivatives contained structural features previously determined to be important for A3 selectivity in adenosine derivatives, such as an N6-(3-iodobenzyl) moiety, and were further substituted at the 2-position with halo, amino, or thio groups. Affinity was determined in radioligand binding assays at rat brain A3 receptors stably expressed in Chinese hamster ovary (CHO) cells, using [125I]AB-MECA (N6-(4-amino-3-iodobenzyl)adenosine-5'-(N-methyluronamide)), and at rat brain A1 and A2a receptors using [3H]-N6-PIA ((R)-N6-phenylisopropyladenosine) and [3H]CGS 21680 (2-[[[4-(2-carboxyethyl)-phenyl]ethyl]amino]-5'- (N-ethylcarbamoyl)adenosine), respectively. A series of N6-(3-iodobenzyl) 2-amino derivatives indicated that a small 2-alkylamino group, e.g., methylamino, was favored at A3 receptors. N6-(3-Iodobenzyl)-9-methyl-2-(methylthio)adenine was 61-fold more potent than the corresponding 2-methoxy ether at A3 receptors and of comparable affinity at A1 and A2a receptors, resulting in a 3-6-fold selectivity for A3 receptors. A pair of chiral N6-(3-iodobenzyl) 9-(2,3-dihydroxypropyl) derivatives showed stereoselectivity, with the R-enantiomer favored at A3 receptors by 5.7-fold. 2-Chloro-9-(beta-D-erythrofuranosyl)-N6-(3-iodobenzyl)adenine had a Ki value at A3 receptors of 0.28 microM. 2-Chloro-9-[2-amino-2,3-dideoxy-beta-D-5-(methylcarbamoyl)- arabinofuranosyl]-N6-(3-iodobenzyl)adenine was moderately selective for A1 and A3 vs A2a receptors. A 3'-deoxy analogue of a highly A3-selective adenosine derivative retained selectivity in binding and was a full agonist in the inhibition of adenylyl cyclase mediated via cloned rat A3 receptors expressed in CHO cells. The 3'-OH and 4'-CH2OH groups of adenosine are not required for activation at A3 receptors. A number of 2',3'-dideoxyadenosines and 9-acyclic-substituted adenines appear to inhibit adenylyl cyclase at the allosteric "P" site.

Cycloserine-induced lichenoid drug eruption

A 65-year-old male patient who has taken antituberculous drugs including cycloserine for 8 months showed multiple pruritic, violaceous, flat-topped papules and plaques on his back which had developed 5 months into therapy. Histopathologic findings were consistent with lichenoid drug eruption. Patch test with the drugs revealed a strongly positive reaction to cycloserine only. Four months after discontinuation of oral cycloserine, pruritus resolved and the lesions subsided without any new lesions. Cycloserine is one of the antituberculous drugs. Skin manifestations resulting from its administration are reported to be rare, but to our knowledge, this is the first case report of lichenoid drug eruption from its use.

Reproducible elevation of liver transaminases by topical 8-methoxypsoralen

We present a case of a 17-year-old woman with vitiligo who had no known previous liver diseases nor any exposure to concurrent hepatotoxic drugs and who developed a liver injury while on topical methoxypsoralen photochemotherapy (PUVA). The reaction, manifested by elevated liver enzymes, was provoked on 3 consecutive occasions, and on the last one, with 1% methoxypsoralen lotion only. Although the exact mechanism of liver injury in our patient is unknown, it seems to be an idiosyncratic hypersensitivity reaction to topically applied methoxypsoralen.

Selective ligands for rat A3 adenosine receptors: structure-activity relationships of 1,3-dialkylxanthine 7-riboside derivatives

1,3-Dibutylxanthine 7-riboside has been found to be a partial agonist at A3 adenosine receptors (van Galen et al. Mol. Pharmacol. 1994, 45, 1101-1111). 1,3-Dialkylxanthine 7-riboside analogues modified at the 1-, 3-, and 8-purine positions and at the ribose 5'-position were synthesized. The nucleoside analogues were examined for affinity in radioligand binding assays at rat brain A3 adenosine receptors stably expressed in CHO cells, using the radioligand [[125I]-4-amino-3-iodobenzyl]adenosine-5'-N-methyluronamide (AB-MECA). Affinity was assayed at rat brain A1 and A2a receptors using [3H]PIA and [3H]CGS 21680, respectively. The affinity of xanthine 7-ribosides at A3 receptors depended on the 1,3-dialkyl substituents in the order: Pent > or = Bu >> Hx > Pr approximately Me. 1,3-Dipentylxanthine 7-riboside was slightly selective for A3 receptors (2-fold vs A1 and 10-fold vs A2a). 8-Methoxy substitution was tolerated at A3 receptors. 2-Thio vs 2-oxo substitution increased potency at all three subtypes and slightly increased A3 vs A1 selectivity. The 5'-uronamide modification, which was previously found to enhance A3 selectivity in N6-benzyladenosine derivatives, was also incorporated into the xanthine 7-ribosides, with similar results. The affinity of 1,3-dialkylxanthine 7-riboside 5'-uronamides at A3 receptors depended on the N-alkyluronamide substituent in the order: MeNH > EtNH >> NH2 >> Me2N. Affinity of the 5'-uronamides at A3 receptors was dependent on the 1,3-dialkyl substitution in the order: Bu > Pent > Hex. 1,3-Dibutylxanthine 7-riboside 5'-N-methylcarboxamide, with a Ki value of 229 nM at A3 receptors, was 160-fold selective for rat A3 vs A1 receptors and > 400-fold selective vs A2a receptors. This derivative acted as a full agonist in the A3 receptor-mediated inhibition of adenylate cyclase.

2-Substitution of N6-benzyladenosine-5'-uronamides enhances selectivity for A3 adenosine receptors

Adenosine derivatives bearing an N6-(3-iodobenzyl) group, reported to enhance the affinity of adenosine-5'-uronamide analogues as agonists at A3 adenosine receptors (J. Med. Chem. 1994, 37, 636-646), were synthesized starting from methyl beta-D-ribofuranoside in 10 steps. Binding affinities at A1 and A2a receptors in rat brain membranes and at cloned rat A3 receptors from stably transfected CHO cells were compared. N6-(3-Iodobenzyl)adenosine was 2-fold selective for A3 vs A1 or A2a receptors; thus it is the first monosubstituted adenosine analogue having any A3 selectivity. The effects of 2-substitution in combination with modifications at the N6- and 5'-positions were explored. 2-Chloro-N6-(3-iodobenzyl)adenosine had a Ki value of 1.4 nM and moderate selectivity for A3 receptors. 2-Chloro-N6-(3-iodobenzyl)adenosine- 5'-N-methyluronamide, which displayed a Ki value of 0.33 nM, was selective for A3 vs A1 and A2a receptors by 2500- and 1400-fold, respectively. It was 46,000-fold selective for A3 receptors vs the Na(+)-independent adenosine transporter, as indicated in displacement of [3H]N6-(4- nitrobenzyl)-thioinosine binding in rat brain membranes. In a functional assay in CHO cells, it inhibited adenylate cyclase via rat A3 receptors with an IC50 of 67 nM. 2-(Methylthio)-N6-(3-iodobenzyl)-adenosine-5'-N-methyluronamide and 2-(methylamino)-N6-(3-iodobenzyl)adenosine-5'-N-methyluronamide were less potent, but nearly as selective for A3 receptors. Thus, 2-substitution (both small and sterically bulky) is well-tolerated at A3 receptors, and its A3 affinity-enhancing effects are additive with effects of uronamides at the 5'-position and a 3-iodobenzyl group at the N6-position.

Structure-activity relationships of 1,3-dialkylxanthine derivatives at rat A3 adenosine receptors

1,3-Dialkylxanthine analogues containing carboxylic acid and other charged groups on 8-position substituents were synthesized. These derivatives were examined for affinity in radioligand binding assays at rat brain A3 adenosine receptors stably expressed in CHO cells using the new radioligand [125I]AB-MECA (N6-(4-amino-3-iodobenzyl)adenosine-5'-N-methyluronamide), and at rat brain A1 and A2a receptors using [3H]PIA and [3H]CGS 21680, respectively. A synthetic strategy for introducing multiple carboxylate groups at the 8-position using iminodiacetic acid derivatives was explored. The presence of a sulfonate, a carboxylate, or multiple carboxylate groups did not result in a significant enhancement of affinity at rat A3 receptors, although as previously observed an anionic group tended to diminish potency at A1 and A2a receptors. The rat A3 receptor affinity was not highly dependent on the distance of a carboxylate group from the xanthine pharmacophore. 2-Thio vs 2-oxo substitution favored A3 potency, and 8-alkyl vs 8-aryl substitution favored A3 selectivity, although few derivatives were truly selective for rat A3 receptors. 1,3-Dimethyl-8-(3-carboxypropyl)-2-thioxanthine was 7-fold selective for A3 vs A2a receptors. 1,3,7-Trimethyl-8-(trans-2-carboxyvinyl)xanthine was somewhat selective for A3 vs A1 receptors. For 8-arylxanthines affinity at A3 receptors was enhanced by 1,3-dialkyl substituents, in the order dibutyl > dipropyl > diallyl.

Effect of pretreatment with diltiazem on left ventricular function and intracellular calcium distribution in postischemic reperfused guinea-pig hearts

BACKGROUND

It has been previously demonstrated that pretreatment with diltiazem preserves mitochondrial function during postischemic reperfusion.

AIM

The purpose of this study was to perform cytochemical and hemodynamical assessment to confirm this demonstration.

METHODS

Isolated Langendorff-perfused guinea-pig hearts received 10 min of diltiazem (7.5 microM) treatment, were subjected to 10 min of global ischemia and to 20 min of reperfusion. Left ventricular function was monitored by connecting a balloon to a pressure transducer. Intracellular calcium was precipitated with potassium pyroantimonate and examined with a transmission electron microscope.

RESULTS

Compared with the control and the ischemic hearts, the diltiazem-pretreated hearts showed a significant increase in the left ventricular developed pressure (LVDP), dP/dtmax (P < 0.01), and recovery rates of the LVDP (P < 0.01 versus ischemic hearts) and dP/dtmax (P < 0.05), and a decrease in the heart rate (P < 0.01). The left ventricular end-diastolic pressure (LVEDP) and leakage of creatine kinase were not significantly different. Calcium deposits were seen along the inner aspects of the sarcolemma and t-tubule membranes, and in the mitochondria of the control hearts. The number of these deposits was considerably reduced after ischemia. They reappeared principally in the mitochondria by reperfusion. In contrast, the calcium deposits reappeared along the sarcolemma, t-tubule membranes, and cell junctions, and in the mitochondria in the diltiazem-pretreated hearts.

CONCLUSION

These results suggest that pretreatment with diltiazem may improve cardiac function during postischemic reperfusion, probably in part by maintenance of sarcolemmal integrity rather than by mitochondrial buffering function.

Measurement of submicrometer A1(2)O(3) particles in plumes

We made multiple-wavelength light transmission measurements at the edge of a plume from a small solid-propellant motor in order to determine the mean particle size and the in situ particle index of refraction. We retrieved the particle size distribution from the Sauter mean diameter and the geometrical standard deviation assuming a lognormal distribution. The good correlation of the data indicated the applicability of the technique with a relatively high confidence level and that submicrometer particles were dominantly present at the edge of the plume. This was confirmed by the size distribution of collected particles. The values measured for alumina particles in the edge of the plume were a Sauter mean diameter of 0.150 µm ± 4%, a geometrical standard deviation of 1.50 ± 3%, and a real index of refraction of 1.63 ± 8%.

Structure-activity relationships of beta-D-(2S,5R)- and alpha-D-(2S,5S)-1,3-oxathiolanyl nucleosides as potential anti-HIV agents

The beta-D-(2S,5R)- and alpha-D-(2S,5S)-1,3-oxathiolanylpyrimidine and -purine nucleosides with natural nucleoside configuration were synthesized and evaluated against HIV-1 in human peripheral blood mononuclear (PBM) cells. The key intermediate 14, which was utilized for the synthesis of various nucleosides, was synthesized from D-mannose or D-galactose. Condensation of the acetate 14 with thymine, uracil, cytosine, and 5-substituted uracils and cytosines gave various pyrimidine nucleosides. The acetate 14 was also condensed with 6-chloropurine and 6-chloro-2-fluoropurine which were converted to various purine nucleosides. In the case of thymine, uracil, and 5-substituted uracil derivatives, most of the compounds did not exhibit any significant anti-HIV activity except 5-fluorouracil (alpha-isomer) derivative 55. Among 5-substituted cytosine analogues, 5-bromocytosine derivative (beta-isomer) 68 was found to be the most potent anti-HIV agent. In the case of purine derivatives, inosine analogue (beta-isomer) 78 was found to be the most potent anti-HIV agent in the 6-substituted purines and 2-amino-6-chloropurine derivative (beta-isomer) 90 showed the most potent activity in the 2,6-disubstituted purine series. The beta-isomers of 6-chloropurine (74), adenine (76), and N6-methyladenine (77) derivatives showed similar potencies against HIV-1, and the corresponding alpha-isomers also exhibited significant anti-HIV activity, although they were generally less potent than the beta-isomers.

L-beta-(2S,4S)- and L-alpha-(2S,4R)-dioxolanyl nucleosides as potential anti-HIV agents: asymmetric synthesis and structure-activity relationships

In order to study the structure-activity relationships of L-(2S,4S)- and L-(2S,4R)-dioxolanyl nucleoside as potential anti-HIV agents, various enantiomerically pure L-(2S,4S)- and (2S,4R)-dioxolanylpyrimidine and -purine nucleosides have been synthesized and evaluated against HIV-1 in human peripheral blood mononuclear (PBM) cells. The enantiomerically pure key intermediate 8 has been synthesized in six steps from 1,6-anhydro-beta-L-gulose (2), and compound 8 was condensed with 5-substituted pyrimidines, 6-chloropurine, and 2,6-disubstituted purine to obtain various dioxolanylpyrimidine and -purine nucleosides, respectively. Among the compound synthesized, 5-fluorocytosine derivative 29 was found to exhibit the most potent anti-HIV activity (EC50 = 0.0012 microM) although it was toxic (IC50 = 10.0 microM). The order of anti-HIV potency of pyrimidine analogues was as follows: 5-fluorocytosine (beta-isomer) > cytosine (beta-isomer) > 5-fluorocytosine (alpha-isomer) > 5-iodocytosine (beta-isomer) > cytosine (alpha-isomer) > 5-bromocytosine (beta-isomer) > thymine (beta-isomer) > 5-methylcytosine (alpha-isomer) > 5-iodocytosine (alpha-isomer) > 5-chlorocytosine (beta-isomer). The anti-HIV potency of purine analogues was found to be in the following decreasing order: 2,6-diaminopurine (beta-isomer) > 2-chloroadenine (alpha-isomer) > 2-fluoroadenine (beta-isomer) > adenine (beta-isomer) > 2-amino-6-chloropurine (alpha-isomer) > 2-amino-6-chloropurine (beta-isomer) > guanine (beta-isomer) > 2-fluoroadenine (alpha-isomer) > adenine (alpha-isomer) > 2,6-diaminopurine (alpha-isomer) > N6-methyladenine (beta-isomer). It is interesting to note that the alpha-5-fluorocytosine analogue exhibited an excellent anti-HIV activity (EC50 = 0.063 microM) without cytotoxicity up to 100 microM in PBM cell.

Asymmetric synthesis and biological evaluation of beta-L-(2R,5S)- and alpha-L-(2R,5R)-1,3-oxathiolane-pyrimidine and -purine nucleosides as potential anti-HIV agents

In order to study the structure-activity relationships of L-oxathiolanyl nucleosides as potential anti-HIV agents, a series of enantiomerically pure L-oxathiolanyl pyrimidine and purine nucleosides were synthesized and evaluated for anti-HIV-1 activity in human peripheral blood mononuclear (PBM) cells. The key intermediate 8 was synthesized starting from L-gulose via 1,6-thioanhydro-L-gulopyranose. The acetate 8 was condensed with thymine, 5-substituted uracils and cytosines, 6-chloropurine, and 6-chloro-2-fluoropurine to give pyrimidine and purine nucleosides. Upon evaluation of these final nucleosides, the 5-fluorocytosine derivative 51 was found to be the most potent compound among those tested. In the case of 5-substituted cytosine analogues, the antiviral potency was found to be in the following decreasing order: cytosine (beta-isomer) > 5-iodocytosine (beta-isomer) > 5-fluorocytosine (alpha-isomer) > 5-methylcytosine (alpha-isomer) > 5-methylcytosine (beta-isomer) > 5-bromocytosine (beta-isomer) > 5-chlorocytosine (beta-isomer). Among the thymine, uracil, and 5-substituted uracil derivatives, thymine (alpha-isomer) and uracil (beta-isomer) derivatives exhibited moderate anti-HIV activity. In the purine series, the antiviral potency is found to be in the following decreasing order: adenine (beta-isomer) > 6-chloropurine (beta-isomer) > 6-chloropurine (alpha-isomer) > 2-NH2-6-Cl-purine (beta-isomer) > guanine (beta-isomer) > N6-methyladenine (alpha-isomer) > N6-methyladenine (beta-isomer). The cytotoxicity was also determined in human PBM cells as well as Vero cells. None of the synthesized nucleosides was toxic up to 100 microM in PBM cells.

1,3-dioxolanylpurine nucleosides (2R,4R) and (2R,4S) with selective anti-HIV-1 activity in human lymphocytes

In order to study the structure-activity relationships of dioxolane nucleosides as potential anti-HIV-1 agents, various enantiomers of pure dioxolanylpurine nucleosides were synthesized and evaluated against HIV-1 in human peripheral blood mononuclear cells. The enantiomerically pure key intermediate 1, which was synthesized in nine steps from 1,6-anhydro-beta-D-mannose, was condensed with 6-chloropurine, 6-chloro-2-fluoropurine, and 2,6-dichloropurine in the presence of TMS triflate. The chloro or fluoro substituents were readily converted into amino, N-methylamino, hydroxy, methoxy, thiol, and methylthio under appropriate reaction conditions. Upon evaluation of these dioxolanes, the guanine derivative 24 exhibited the most potent anti-HIV-1 activity without cytotoxicity up to 100 microM in various cells. The decreasing antiviral activity order of beta-isomers was as follows: guanine > 6-chloro-2-aminopurine > 2-fluoroadenine > or = adenine > or = 2,6-diaminopurine > hypoxanthine > 2-chloroadenine > 6-chloropurine approximately equal to N6-methyladenine approximately equal to 6-mercaptopurine approximately equal to 6-(methylthio)purine.

Asymmetric synthesis of 1,3-dioxolane-pyrimidine nucleosides and their anti-HIV activity

In order to study the structure-activity relationships of dioxolane nucleosides as potential anti-HIV agents, various enantiomerically pure dioxolane-pyrimidine nucleosides have been synthesized and evaluated against HIV-1 in human peripheral blood mononuclear cells. The enantiomerically pure key intermediate 8 has been synthesized in nine steps from 1,6-anhydro-D-mannose (1), which was condensed with 5-substituted pyrimidines to obtain various dioxolane-pyrimidine nucleosides. Upon evaluation of these compounds, cytosine derivative 19 was found to exhibit the most potent anti-HIV agent although it is the most toxic. The order of anti-HIV potency was as follows: cytosine (beta-isomer) greater than thymine greater than cytosine (alpha-isomer) greater than 5-chlorouracil greater than 5-bromouracil greater than 5-fluorouracil derivatives. Uracil, 5-methylcytosine, and 5-iodouracil derivatives were found to be inactive. Interestingly, alpha-isomer 20 showed good anti-HIV activity without cytotoxicity. As expected, other alpha-isomers did not exhibit any significant antiviral activity. (-)-Dioxolane-T was 5-fold less effective against AZT-resistant virus than AZT-sensitive virus.

Demonstration of estrogen receptor by immunohistochemical staining in paraffin sections of breast carcinoma

Paraffin embedded sections of 64 breast carcinomas were stained immunohistochemically using a commercially available monoclonal antibody to estrogen receptor. To improve the sensitivity of the staining, the authors used a Pronase enzyme pretreatment, biotinylated antibody to rat IgG as secondary antibody, streptavidin-alkaline phosphatase as tertiary reagent and fast red as chromogen. When compared to the results of estrogen receptor enzyme immunoassay, this method yielded an 85.9% concordance rate, 86.2% specificity and 85.7% sensitivity. When compared to estrogen receptor immunocytochemistry(ER-ICA) in frozen section and considering the inherent advantages of immunohistochemical staining over biochemical assay, the major advantages of this method are good morphology, suitability for retrospective study and reduced cost of staining due to dilution of expensive primary antibody. Thus, this method offers an alternative to ER assay using fresh tissue and should provide additional valuable information about estrogen receptor.

[A study on the effect of waiting time for operations in the operating room on preoperative patients]

This study was attempted to provide us with basic information on how to improve understanding with patients for operation, and to offer them better nursing and treatment. This kind of study will help scientific application to nursing practice and operating room. The data was collected by interviewing 29 patients who underwent the elective surgery under the general anesthesia at Y hospital in Seoul. The interview ran from October 15 to December 15, 1989. The research instrument was a anxiety measurement device (SAAI) originally developed by Spielberger, et al and modified by Jung-Tack Kim. 1. Hypothesis Testing Hypothesis one was that there would be a difference in state anxiety level according to a time difference in waiting for operation. This hypothesis was rejected (state anxiety level one hour before operation P greater than .05, r = .747, State anxiety level half an hour before operation P greater than .05, r = .1550, state anxiety level just before operation, P greater than .05, r = .1099). However, state anxiety level appeared to be associated with a longer waiting period, like one day before operation (P less than .05, r = .4628). Hypothesis two was that there would be a difference according to state anxiety level of patients for operation. This was rejected. (Change of blood pressure in systolic P greater than .05, r = -.1082. Change of blood pressure in diastolic P greater than .05, r = -.088, Change of pulse rate, P less than .05, r = 1.909) 2. Examining trait anxiety and state anxiety levels, the average level of trait anxiety was 42.034, and the average level of state anxiety one day before operation was 43,000. The average level of state anxiety was averaged 42.356 in a waiting room for operation. 3. Examining the state anxiety level by time period, the level one hour before was 42.379, the level half an hour before 42.276, and the level just before operation 42.414. The low level of state anxiety was due to the fact that premedication was not eliminated. 4. Age and time period like one day before operation was related to state anxiety level (F = 5.271, P less than .001) and blood pressure in waiting room for operation. That is, state anxiety level and blood pressure of patients one day before operation appeared high. Sex was related to changes of blood pressure; the blood pressure of male patients appeared higher than that of female patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Hepatitis C infection in hemodialysis units

We performed an epidemiological study of the hepatitis C infection on 112 patients of 3 urban hemodialysis units using a recently developed anti-HCV recombinant based assay. Eleven patients (9.8%) were positive for anti-HCV. Among them, 8 (72.7%) were positive for anti-HBc, one of whom was HBsAg positive and 6 of whom were also anti-HBs positive. Surprisingly, all of the anti-HCV (+) patients were normal alanine aminotransferase. The mean age of the anti-HCV (+) patients was 50.7 +/- 3.3 (mean +/- SE) and that of the anti-HCV (-) was 47.6 +/- 1.3. The mean duration (month) of hemodialysis of the anti-HCV (+) and anti-HCV (-)groups were 52.7 +/- 7.2 (mean +/- SE) and 60.9 +/- 9.7, respectively. The prevalence of anti-HCV among anti-HBc positive subjects was 9.5% and that among anti-HBc negative subjects was 17.6%. This didn't have any statistical significance according to the criteria of the study (p = 0.308). The prevalence of anti-HCV among the transfusion positive group was 11.0% and that of the transfusion negative group was 7.7%. This data showed the tendency for a higher prevalence of anti-HCV among the transfusion positive group, but this also didn't reach statistical significance (p = 0.424). Of the 40 normal controls, none were anti-HCV positive. The prevalence of HBsAg in our hemodialysis units was 12.5%. This rate was not so much higher than the average population in Korea. The prevalence of anti-HCV and previous hepatitis B virus infection also had no significant relationship.(ABSTRACT TRUNCATED AT 250 WORDS)