Identification of Rho GTPase-dependent sites in the Dbl homology domain of oncogenic Dbl that are required for transformation

The Dbl family guanine-nucleotide exchange factors (GEFs) for Rho GTPases share the structural array of a Dbl homology (DH) domain in tandem with a Pleckstrin homology (PH) domain. For oncogenic Dbl, the DH domain is responsible for the GEF activity, and the DH-PH module constitutes the minimum structural unit required for cellular transformation. To understand the structure-function relationship of the DH domain, we have investigated the role of specific residues of the DH domain of Dbl in interaction with Rho GTPases and in Dbl-induced transformation. Alanine substitution mutagenesis identified a panel of DH mutants made in the alpha1, alpha6, and alpha9 regions and the PH junction site that suffer complete or partial loss of GEF activity toward Cdc42 and RhoA. Kinetic and binding analysis of these mutants revealed that although most displayed decreased k(cat) values in the GEF reaction, the substrate binding activities of T506A and R634A were significantly reduced. E502A, Q633A, and N673A/D674A, on the other hand, retained the binding capability to the Rho GTPases but lost the GEF catalytic activity. In general, the in vitro GEF activity of the DH mutants correlated with the in vivo Cdc42- and RhoA-activating potential, and the GEF catalytic efficiency mirrored the transforming activity in NIH 3T3 cells. Moreover, the N673A/D674A mutant exhibited a potent dominant-negative effect on serum-induced cell growth and caused retraction of actin structures. These studies identify important sites of the DH domain involved in binding or catalysis of Rho proteins and demonstrate that maintaining a threshold of GEF catalytic activity, in addition to the Rho GTPase binding activity, is essential for efficient transformation by oncogenic Dbl.

[The toxicity of busulphan and cyclophosphamide as the preparative regimen for allogeneic peripheral blood stem cell transplantation]

OBJECTIVE

To analyse the treatment-related complications of busulphan and cyclophosphamide (BU-CY) as the conditioning regimen for allogeneic peripheral blood stem cell transplantation (allo-PBSCT).

METHODS

The clinical data of 40 leukemia patients undergoing allo-PBSCT between June 1997 and May 1999 in our BMT center were retrospectively analysed.

RESULTS

Recovery of neutrophil and platelet was achieved at a median of day +13 (9 - 28) and day +12 (7 - 60) respectively. Acute GVHD occurred in 17 of 40 patients (42.5%) with grade II-IV in 10 patients (25%). Chronic GVHD developed in 21 out of 30 evaluable patients (70%). Mild to severe mucositis occurred in 30 patients (75%), and 4 of them had severe esophagitis with bleeding. Haemorrhagic cystitis developed in 8/40 (20%) patients, the median time of its onset was day +100 (+7 to +165). Six of 40 patients (15%) developed interstitial pneumonia (IP), 5 of them were due to cytomegalovirus infection, and the remaining one due to pneumocystis carinii infection. No hepatic veno-occlusive disease was observed and no seizure occurred. During the median follow-up of 480 (300 - 1000) days, 4 (10%) patients relapsed and 8 (20%) patients died of the transplant-related complications. The 3 year leukemia-free survival rate was 70%.

CONCLUSION

BU (domestic busulfan)-CY regimen is relatively easy to administer and well tolerated, with low extramedullary toxicities.

[Development of a system for Polymyxa graminis infection and transmission of wheat yellow mosaic virus]

In growth chambers, a system was developed for infection of Polymyxa graminis to wheat(Triticum aestivum L.), which is an obligate parasite. By the system, the fungus could be propagated in large quantity rapidly and the life cycle of P. graminis in wheat was observed in a period of 13 to 15 days. The methods for separating P. graminis as single cystosori from cultured wheat roots or dried roots were simplified. By tests for the factors affecting on P. graminis infection, including inocula types, seedling age of host plants, temperatures, pH value and nutrient contents etc., the system was modified to more perfection. With an integration of optimal temperature and other elements in the system, which affect on infection and development of P. graminis, wheat yellow mosaic virus (WYMV) was transmitted constantly and efficiently by the fungal vector. In average, 70% of wheat plants inoculated by the viruliferous fungi could infected by WYMV and the typical symptom of wheat mosaic disease would appear at 30 days post-inoculation mechanically.

Xenotransplantation of microencapsulated bovine chromaffin cells into hemiparkinsonian monkeys

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

Sphingosylphosphorylcholine is a ligand for ovarian cancer G-protein-coupled receptor 1

Sphingosylphosphorylcholine (SPC) is a bioactive lipid that acts as an intracellular and extracellular signalling molecule in numerous biological processes. Many of the cellular actions of SPC are believed to be mediated by the activation of unidentified G-protein-coupled receptors. Here we show that SPC is a high-affinity ligand for an orphan receptor, ovarian cancer G-protein-coupled receptor 1 (OGR1). In OGR1-transfected cells, SPC binds to OGR1 with high affinity (Kd = 33.3 nM) and high specificity and transiently increases intracellular calcium. The specific binding of SPC to OGR1 also activates p42/44 mitogen-activated protein kinases (MAP kinases) and inhibits cell proliferation. In addition, SPC causes internalization of OGR1 in a structurally specific manner.

Recruiting elderly African-American women in cancer prevention and control studies: a multifaceted approach and its effectiveness

Barriers to engaging African Americans as research participants may be accentuated among older single African-American women partly because of financial, social, physical, and cognitive factors. This article shows our multifaceted strategies and experiences in the recruitment of single African-American women aged 65 and older in a cancer prevention and control study. The study was conducted in 10 public housing complexes in Nashville, Tennessee. Out of 367 eligible women, 325 participated in the study, resulting in a rate of 89%. The result suggests that a strategy, which targets the cultural, perceptive, and cognitive characteristics of the population, was effective for increasing the enrollment of study subjects in this population. Because the single constitute 75% of African-American women aged 65 and older; and the incidence and mortality of cancer are especially high in elderly African Americans, our experiences are encouraging for cancer prevention and control research in the population.

Preventable risk factors for nasal cancer

PURPOSE

To determine preventable risk factors for cancers of the nasal cavity and paranasal sinuses in the United States, we analyzed data from the population-based, case-control Selected Cancers Study.

METHODS

Cases were men born between 1929 and 1953 who were diagnosed with primary nasal cancer between 1984 and 1988 and identified from population-based cancer registries; we narrowed the cohort to 70 subjects whose diagnosis of nasal cancer was confirmed by pathology review. All living controls interviewed for the Selected Cancers Study were included as the comparison group (n = 1910); they were recruited by random-digit dial telephone and were frequency-matched to the lymphoma cases of the Selected Cancers Study by geographic area and age. Both cases and controls were interviewed by telephone.

RESULTS

Logistic regression analyses showed that cases were 2.5 times more likely than controls to have smoked cigarettes [95% confidence interval (CI) = 1.1-5.3], and 2.2 times more likely to have worked in selected occupations, including lawn care, forestry, and maintenance of highway right-of-way areas (CI = 1.2-3.7). These occupations may cause workers to be exposed to pesticides or herbicides. The population attributable risk (PAR) was 53% for having ever smoked cigarettes.

CONCLUSIONS

The study results suggest that among U.S. men, some nasal cancer may be preventable by avoiding cigarette smoking.

Detergent-induced conformational changes of Humicola lanuginosa lipase studied by fluorescence spectroscopy

Detergent (pentaoxyethylene octyl ether, C(8)E(5))-induced conformational changes of Humicola lanuginosa lipase (HLL) were investigated by stationary and time-resolved fluorescence intensity and anisotropy measurements. Activation of HLL is characterized by opening of a surface loop (the "lid") residing directly over the enzyme active site. The interaction of HLL with C(8)E(5) increases fluorescence intensities, prolongs fluorescence lifetimes, and decreases the values of steady-state anisotropy, residual anisotropy, and the short rotational correlation time. Based on these data, we propose the following model. Already below critical micellar concentration (CMC) the detergent can intercalate into the active site accommodating cleft, while the lid remains closed. Occupation of the cleft by C(8)E(5) also blocks the entry of the monomeric substrate, and inhibition of catalytic activity at [C(8)E(5)] less than or equal to CMC is evident. At a threshold concentration close to CMC the cooperativity of the hydrophobicity-driven binding of C(8)E(5) to the lipase increases because of an increase in the number of C(8)E(5) molecules present in the premicellar nucleates on the hydrophobic surface of HLL. These aggregates contacting the lipase should have long enough residence times to allow the lid to open completely and expose the hydrophobic cleft. Concomitantly, the cleft becomes filled with C(8)E(5) and the "open" conformation of HLL becomes stable.

[Preparation, characterization and drug release characteristics of poly(lactide)(PL)/poly(lactide-co-polyethylene glycol)(PLEG) blend microspheres]

PL and PLEG are biodegradable, biocompatible polymers. They have been widely used for controlled release of drugs. We synthesized PLEG copolymers containing PEG segments with various molecular weight and prepared hCG-loaded PL/PLEG blend microspheres to improve hCG entrapment efficiency. It was shown that the hCG entrapment effciency of PL/PLEG microspheres was higher than that of PL or PLEG microspheres when P(L-co-PEG6000)(90:10) was used. In vitro release test showed that the release of hCG was a burst-slow process, which was thought to be good for antigens to produce antibodies.

Steady state and time resolved effects of guanidine hydrochloride on the structure of Humicola lanuginosa lipase revealed by fluorescence spectroscopy

Effects of guanidine hydrochloride (GdnHCl) on the structure and dynamics of wild-type Humicola lanuginosa lipase (HLL) and its two mutants were studied. The latter were S146A (with the active site Ser replaced by Ala) and the single Trp mutant W89m, with substitutions W117F, W221H, and W260H. Steady-state, stopped-flow, and time-resolved laser-induced fluorescence spectroscopy were carried out as a function of [GdnHCl]. The maximum emission wavelength and fluorescence lifetimes revealed the microenvironment of the tryptophan(s) in these lipases to become more polar upon increasing [GdnHCl]. However, significant extent of tertiary structure in GdnHCl is suggested by the observation that both wild-type HLL and W89m remain catalytically active at rather high GdnHCl concentrations of >6 and 4.0 M, respectively. Changes in steady-state emission anisotropy, as well as variation in rotational correlation times and residual anisotropy values, demonstrate that upon increasing [GdnHCl] the structure of the lipases became more loose, with increasing amplitude of structural fluctuations. Finally, intermediate states in the course of exposure of the proteins to GdnHCl were revealed by stopped-flow fluorescence measurements.

Adriamycin inhibits human RH II/Gu RNA helicase activity by binding to its substrate

RNA helicases are enzymes important in RNA synthesis, processing, transport, and turnover. Human nucleolar RNA helicase II/Gu protein (RH II/Gu) was expressed in a baculovirus system. The purified recombinant RH II/Gu protein has RNA helicase activity on a 5' tailed ds RNA substrate in vitro. We found that Adriamycin, a widely used anticancer drug, inhibited RH II/Gu helicase activity in a dose-dependent manner with an IC(50) of 40 microM. Adriamycin bound to the RNA substrate, and the binding was disrupted by boiling or treatment with 1% SDS, suggesting that the binding of Adriamycin to RNA is reversible. Adriamycin was also found by gel electrophoresis to bind to yeast tRNA to form slow-migrating complexes. These results suggest that Adriamycin can inhibit RNA synthesis or processing by binding to RNA substrates.

p53 induces TAP1 and enhances the transport of MHC class I peptides

The transporter associated with antigen processing (TAP) 1 is required for the major histocompatibility complex (MHC) class I antigen presentation pathway, which plays a key role in host tumor surveillance. Since more than 50% of tumors have a dysfunctional p53, evasion of tumor surveillance by tumor cells may be linked to loss of p53 function. Here we found that TAP1 is strongly induced by p53 and DNA-damaging agents through a p53-responsive element. We also found that p73, which is homologous to p53, is capable of inducing TAP1 and cooperates with p53 to activate TAP1. Furthermore, we found that by inducing TAP1, p53 enhances the transport of MHC class I peptides and expression of surface MHC-peptide complexes, and cooperates with interferon gamma to activate the MHC class I pathway. These results suggest that tumor surveillance may be a mechanism by which p53 and/or p73 function as tumor suppressors.

[Cloning of DNA fragment related to salt tolerance in Sinorhizobium meliloti 042B]

Total DNA partially digested by EcoR I was prepared for S. meliloti 042B, in which 15-25 kb DNA fragments were collected. Vector pLAFR I was purified and digested by EcoR I, and then the various DNA fragments of 042B were ligated with pLAFR I by T4DNA ligase. Gene library of S. meliloti 042B was constructed with pLAFR I using E. coli S17-1 as recipient. The number of bacterial recombinants obtained was about 8,000 and 95% of them contained foreign DNA fragments. Using NTG, 042B was mutated on FY plates and 12 sensitive strains were screened at 0.5 mol/L NaCl from 2,000 colonies. One of them was named GZ17 and selected as a recipient strain. By biparental mating the foreign DNA fragments were introduced from gene library of strain 042B into recipient strain GZ17 which is sensitive to 0.5 mol/L NaCl. Then the transconjugants were grown on FY plates containing tetracycline (20 micrograms/mL) and 0.5 mol/L NaCl. A 7 kb inserted DNA fragment related to salt tolerance was obtained. In subcloning experiment, a 4 kb DNA fragment related to salt tolerance was obtained.

The multiple roles of conserved arginine 286 of 1-aminocyclopropane-1-carboxylate synthase. Coenzyme binding, substrate binding, and beyond

A pyridoxal 5'-phosphate (PLP)-dependent enzyme, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (S-adenosyl-L-Met methylthioadenosine-lyase, EC 4.4.1.14), catalyzes the conversion of S-adenosyl-L-methionine (AdoMet) to ACC. A tomato ACC synthase isozyme (LE-ACS2) with a deletion of 46 amino acids at the C terminus was chosen as the control enzyme for the study of the function of R286 in ACC synthase. R286 of the tomato ACC synthase was mutated to a leucine via site-directed mutagenesis. The ACC synthase mutant R286L was purified using a simplified two-step purification protocol. Circular dichroism (CD) analysis indicated that the overall three-dimensional structure of the mutant was indistinguishable from that of the control enzyme. Fluorescence spectroscopy revealed that the binding affinity of R286L ACC synthase for its cofactor PLP was reduced 20- to 25-fold compared with control. Kinetic analysis of R286L showed that this mutant ACC synthase had a significantly reduced turnover number (k(cat)) of 8.2 x 10(-3) s(-1) and an increased K(m) of 730 microM for AdoMet, leading to an 8,000-fold decrease in overall catalytic efficiency compared with the control enzyme. Thus, R286 of tomato ACC synthase is involved in binding both PLP and AdoMet.

Preventive practicum training in healthcare organizations. The Meharry model

BACKGROUND

Practicum training for preventive medicine residents often occurs in agencies whose community is geographically defined and whose governance is closely linked to public election. We were unsure about the financial ability of such departments to support training and are concerned that over-reliance on traditional health departments might not be best for either medically indigent populations or preventive medicine. We, therefore, sought to apply a public health model--based on a strategic partnership between nursing and preventive medicine--to a large health care organization. The result was formation of a mini-health department, suitable for fully accredited preventive medicine practicum training, within the Alvin C. York Veterans Affairs Medical Center, Murfreesboro, TN. This Center serves a defined population of 21,594 patients and about 1600 employees. The theoretical framework for the new department was based on demonstration of a close fit between the competencies expected of preventive medicine physicians by the American College of Preventive Medicine (ACPM) and activities required by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO). Because of JCAHO requirements, many healthcare organizations already pay for preventive medicine services.

CONCLUSIONS

By placing preventive medicine training faculty into existing budget slots at our institution, systemwide personnel costs for prevention decreased by about $36,000 per year, even as personnel funding for preventive medicine physicians increased from about $24,000 to $376,000 per year. Moreover, there was dramatic, sustained improvement in 17 indicators of preventive care quality as determined by an external peer review organization. In addition to providing a new venue for training, this model may also improve the quality and reach of preventive services, decreased fixed costs for service delivery, and yield new employment opportunities for preventive medicine physicians.

[Progress in studies on cavitation of mechanical heart valve]

This paper reviews the researches on cavitation of mechanical heart valve in recent years and presents a discussion on the research methods. The achievements are summarized and the prospects of further research on cavitation in mechanical heart valve are brought forth.

Comparison of self-report data and medical records data: results from a case-control study on prostate cancer

BACKGROUND

Self-report and review of medical records are the most common methods for the assessment of past exposures. However, information obtained from self-reports and medical records may not be consistent. This study compared information provided in a self-administered questionnaire with medical records data.

METHODS

Self-report and medical records data came from a case-control study on prostate cancer. Cases were 181 patients with primary prostate cancer and controls were 297 men without the disease, enrolled in Group Health Cooperative (GHC) in Seattle. The consistencies between the two data sources were examined.

RESULTS

In general, agreement between the two data sources was almost perfect for demographic and anthropometric variables, substantial for the history of inguinal hernia and kidney stones, and moderate for vasectomy, family history of prostate cancer, smoking and alcohol consumption. However, the two data sources generally were poorly concordant for prior genitourinary diseases that have less explicit diagnostic criteria such as benign prostatic hyperplasia and prostatitis. Analyses of discordant data showed that men were more likely to report an exposure or medical condition that could not be verified from medical records. No discernible patterns in the difference of agreement were found according to age, GHC membership length or case-control status.

CONCLUSIONS

This study suggests that agreement between self-reported data and medical records data varies depending upon the study variables. While both data sources are subject to some problems, self-report may provide more complete and comparable information, at least for variables unrelated to diagnosis.

[Angiotensin 1-converting enzyme gene insertion/deletion polymorphism in patients with coronary artery disease and essential hypertension and its nucleotide sequence]

OBJECTIVE

To determine angiotensin 1-coverting enzyme(ACE) gene insertion/deletion(I/D) polymorphism distributions in patients with coronary artery disease(CAD) and essential hypertension(EH),and to detect its nucleotide sequence.

METHODS

ACE genotypes of 137 patients with CDA, 42 patients with EH and 63 healthy people were detected by PCR methods. At the same time, nucleotide sequences of D and I allele were determined by fluorescein labeling automatic sequencing method.

RESULTS

the frequency of DD genotype in CAD group was significantly higher than that in control group (0.45 and 0.21,P < 0.01), but there was no significant difference of ACE geneI/D polymorphism distribution between EH and control group. The lengths of D and I alleles are 191bp and 479bp separately and their nucleotide sequences are somewhat different with the results of foreign countries.

CONCLUSION

ACE gene I/D polymorphism is an independent risk factor of CAD, but it has no relationship with EH. A 288bp insertion segment results in the I/D polymorphism of ACE gene.

Irreversible inhibition of human immunodeficiency virus type 1 integrase by dicaffeoylquinic acids

Human immunodeficiency virus type 1 (HIV-1) and other retroviruses require integration of a double-stranded DNA copy of the RNA genome into the host cell chromosome for productive infection. The viral enzyme, integrase, catalyzes the integration of retroviral DNA and represents an attractive target for developing antiretroviral agents. We identified several derivatives of dicaffeoylquinic acids (DCQAs) that inhibit HIV-1 replication in tissue culture and catalytic activities of HIV-1 integrase in vitro. The specific step at which DCQAs inhibit the integration in vitro and the mechanism of inhibition were examined in the present study. Titration experiments with different concentrations of HIV-1 integrase or DNA substrate found that the effect of DCQAs was exerted on the enzyme and not the DNA. In addition to HIV-1, DCQAs also inhibited the in vitro activities of MLV integrase and truncated variants of feline immunodeficiency virus integrase, suggesting that these compounds interacted with the central core domain of integrase. The inhibition on retroviral integrases was relatively specific, and DCQAs had no effect on several other DNA-modifying enzymes and phosphoryltransferases. Kinetic analysis and dialysis experiments showed that the inhibition of integrase by DCQAs was irreversible. The inhibition did not require the presence of a divalent cation and was unaffected by preassembling integrase onto viral DNA. The results suggest that the irreversible inhibition by DCQAs on integrase is directed toward conserved amino acid residues in the central core domain during catalysis.

Differential regulation of cellular target genes by p53 devoid of the PXXP motifs with impaired apoptotic activity

Activation of the p53 tumor suppressor protein can lead to either cell cycle arrest or apoptosis. Several functional domains necessary for mediating cell cycle arrest and apoptosis in p53 have been mapped, e.g., the proline-rich domain. The proline-rich domain is located within residues 60-90, which comprise five PXXP motifs (where P represents proline and X any amino acid). To further delineate the function of the proline-rich domain and its potential role in transactivation, we generated several groups of cell lines that inducibly express various p53 mutants using a tetracycline-regulated expression system. We found that p53(delta62-91), which lacks all five PXXP motifs in human p53, is capable of inducing cell cycle arrest but not apoptosis, while p53(gln22-ser23/delta62-91), which contains a double point mutation in the activation domain as well as deletion of the proline-rich domain, completely loses its activity. However, p53(delta74-91), which contains only one PXXP motif at its N-terminus, is not only capable of inducing cell cycle arrest but also retains a partial apoptotic activity. Furthermore, we found that deletion of the proline-rich region has no or very mild effects on activation of several transiently transfected p53 target gene promoters, i.e., the p21, MDM2, BAX, and GADD45 promoters. However, such deletion differentially affects p53 induction of endogenous target genes, i.e., induction of p21, MDM2, BTG2, p85, PIG3, PIG6 and PIG11 was reduced or abrogated but induction of BAX, KILLER/DR5, PIG2, PIG7 and PIG8 was not substantially affected. Interestingly, induction of GADD45 was enhanced. These results suggest that the proline-rich region may play a role in chromatin remodeling, which counteracts chromatin-mediated repression for some of the endogenous p53 target genes.

Prostate cancer in relation to the use of electric blanket or heated water bed

Using data from a case-control study conducted in Group Health Cooperative (GHC) of Puget Sound, we examined the relation between the use of electric blankets or heated water beds and the risk of prostate cancer. Cases were 175 prostate cancer patients ages 40-69 years. Controls were 258 male GHC members frequency matched to cases. The odds ratio (OR) for prostate cancer associated with the use of an electric blanket or heated water bed was 1.4 (95% confidence interval (CI) 0.9-2.2). The risk, however, did not tend to be higher with increasing months per year or years of use. This study did not provide clear evidence on the hypothesized association.

Structure and mutagenesis of the Dbl homology domain

Guanine nucleotide exchange factors in the Dbl family activate Rho GTPases by accelerating dissociation of bound GDP, promoting acquisition of the GTP-bound state. Dbl proteins possess a approximately 200 residue catalytic Dbl-homology (DH) domain, that is arranged in tandem with a C-terminal pleckstrin homology (PH) domain in nearly all cases. Here we report the solution structure of the DH domain of human PAK-interacting exchange protein (betaPIX). The domain is composed of 11 alpha-helices that form a flattened, elongated bundle. The structure explains a large body of mutagenesis data, which, along with sequence comparisons, identify the GTPase interaction site as a surface formed by three conserved helices near the center of one face of the domain. Proximity of the site to the DH C-terminus suggests a means by which PH-ligand interactions may be coupled to DH-GTPase interactions to regulate signaling through the Dbl proteins in vivo.

[Preparation of 5-fluoruracil-poly-alpha, beta(2-hydroxyethy1)-DL-asparamide and in-vivo release in rabbit]

A polymer release drug was prepared by poly-alpha, beta-(2-hydroxyethyl)-DL-asparamide(PHEA) and 5-fluorouracil. As a model drug 5-fluorouracil was conjugated into the biodegradable polymer by chemical bond. The released drug was determined to be about 37.1% (w/w) and it was characterized by IR spectrum and differential scanning calorimetry (DSC). Two forms of drugs, rod and suspension were prepared and in vivo release experiment were carried out in rabbits. The experimental result showed that the rod form of drug can in some degree reduce initial burst.

Methyl-deficient diets, methylated ER genes and breast cancer: an hypothesized association

Recent molecular studies show that ER-negative breast cancer results from the lack of ER gene transcription due to the methylation of the CpG island 5' to the gene. Because CpG island methylation is an early event in carcinogenesis and because methyl-deficient diets could result in CpG island methylation, it is relevant to postulate that methyl-deficient diets may be a risk factor for breast cancer with methylated ER genes (as opposed to the disease with unmethylated ER genes). This molecular-based etiologic hypothesis may facilitate epidemiological research on the relationship between breast cancer and diet that has been unclear until now.

[The therapeutic effect of purified human leucocytic interferon-alpha on hemorrhagic fever with renal syndrome]

In order to know the therapeutic effect of purified human leucocytic interferon-alpha on hemorrhagic fever with renal syndrome diagnosed early (< or = 5 days). We treated 23 cases with clinical prognosis and antiviral effect significantly better than those of 21 cases in a random control group. The membrane protein (MP), nucleo protein (NP) in peripheral blood mononuclear cells (PBMC) and urine, the serum antibodies to MP and NP were determined before treatment and 2, 4, 6, 8, 10 days after the beginning of the treatment. The results showed that in the treatment group, the expressin of MP and NP in PBMC were significantly depressed. The rate of negative turning of MP and NP in PBMC was 65.22% (15/23) and 69.57% (16/23) in 10 days, while in the control group, it was 19.05% (4/21) and 14.29% (3/21). The rate of negative turning of MP and NP in urine were 78.57% (11/14) and 90.91% (10/11) and that in the control group was 30.00% (3/10) and 16.66% (1/6). There was a significant difference between the two groups (P < 0.01). The results indicated that IFN-alpha could attenuate the lesions caused directly by virus, improve patients condition and raise the cure rate through depressing the expression of the virus.

[Percutaneous transfemoral arterial implantation of drug delivery system for arterial infusion therapy of advanced primary hepatic carcinoma]

OBJECTIVE

To study the efficiency of arterial infusion chemotherapy via drug delivery system (DDS) for advanced primary hepatic carcinoma.

METHODS

Hepatic arterial infusion chemotherapy was performed in 82 cases of primary hepatic carcinoma with no indication for operation or transarterial embolism treatment. The patients were divided into 2 group as follows: (1) Group A: 42 patients were treated intra-arterially once every 1 or 2 weeks via implanted DDS. (2) Group B: 40 patients were treated through one bolus arterial infusion chemotherapy, once every month.

RESULTS

The response rate (CR + PR) was 38.1% and 15.0% respectively in group A and B (P < 0.05); the 0.5-, 1- and 2- year survival rate was 61.9%, 28.6% and 9.5% respectively in group A, but 20%, 5%, 0% respectively in group B (P < 0.01); Liver, biliary, gastrointestinal and bone marrow toxicity in group A patients was greatly lower than those in group B patients.

CONCLUSION

Intermittent arterial infusion chemotherapy via DDS significantly improves survival and quality of life in patients with advanced primary hepatic carcinoma.

Self-reported infectious mononucleosis and 6 cancers: a population-based, case-control study

A study was undertaken to estimate the magnitude of association between self-reported infectious mononucleosis (IM) and 6 types of cancer, including Hodgkin's disease, non-Hodgkin's lymphoma, nasopharyngeal cancer, nasal cancer, primary liver cancer, and sarcoma. Cases were male, aged 15-39 y in 1968, who lived in 8 cancer registry areas. Controls were men selected by random-digit telephone dialing. Cases included 1511 persons with non-Hodgkin's lymphoma, 343 with Hodgkin's disease, 386 with sarcoma and 168, 113 and 70 with primary liver, nasopharyngeal and nasal cancers, respectively. There were 1910 controls. For the 6 cancers combined, the overall odds ratio for IM occurring < 5 and > or = 5 y of the reference date were 5.40 [95% (Confidence Interval (CI) = 1.61, 18.09] and 1.08 (0.84, 1.40), respectively. Analogous values were 4.59 (1.25, 16.85) and 1.07 (0.78, 1.48) for non-Hodgkin's lymphoma and 7.49 (1.52, 36.92) and 1.35 (0.87, 2.09) for Hodgkin's disease. There was the suggestion of a protective association with IM occurring > or = 5 y before cancer onset for the 4 non-lymphomatous cancers. Strongly positive associations between self-reported IM and 6 types of cancer were observed for IM occurring < 5 y before the onset of cancer. There was a suggestion, which is noted with extreme caution, that IM earlier in life might have had a protective association with the 4 non-lymphomatous cancers.

Phospholipase A2 activity in salivary glands and saliva of the lone star tick (Acari: Ixodidae) during tick feeding

Phospholipase A2 (PLA2) activity levels in tick [Amblyomma americanum (L.)] salivary glands and saliva were examined during tick feeding by using 14C-phosphatidylcholine as the substrate. Saliva produced by stimulating female ticks to salivate with dopamine contains PLA2 (ts-PLA2) activity. The ts-PLA2 activity level in saliva did not change significantly during tick feeding except for a decrease in the last rapid feeding phase (> 200 mg) and in replete ticks. Phospholipase A2 activity was higher in salivary glands of fed than unfed ticks, both in males and females; activity increased during tick feeding correlating with salivary secretory rates during tick feeding suggesting that much of the PLA2 activity measured in whole salivary glands is synthesized for subsequent secretion. During the time course of in vitro salivation, the first 10 microliters of saliva contained higher ts-PLA2 activity than saliva secreted thereafter. Phospolipase A2 was identified in the saliva of artificially fed ticks indicating that ts-PLA2 is a physiological component of tick saliva.

[Determination of serotonin in rat brain by gas chromatography/mass spectrometry]

A GC/MS method for the determination of serotonin (5-hydroxytryptamine, 5-HT) has been developed. 5-HT in homogenized rat brain was acylated and extracted into EtOAc. The acylate was further derivatized with heptafluorbutyl anhydride and formed a spirocyclic pentafluoropropionyl derivative. Subsequent analysis of 5-HT derivative by gas chromatography-electron capture negative ion chemical ionization mass spectrometry was highly specific and sensitive. The assay is linear from 0.5 to 50 micrograms/L with a linear equation of Y = 0.134 8X - 0.07995, r = 0.999. The recovery was 98.2% +/- 3.8% (n = 10) and the limit of detection was 0.5 microgram/L. The reproducibility of 5-HT determination in rat brain was less than 10% (RSD) at both levels of 1.0 microgram/L and 50.0 micrograms/L. The method has been applied to analysis of 5-HT in the dose rat brain successfully.

Non-Hodgkin's lymphoma and family history of malignant tumors in a case-control study (United States)

Using data from a case-control study in the United States (the Selected Cancers Study), we examined the relationship between non-Hodgkin's lymphoma (NHL) and family history of different cancers. Cases were 1,511 men aged 31 to 59 years and diagnosed pathologically with non-Hodgkin's lymphoma during 1984-88. Controls were men, frequency-matched to cases by age range and cancer registry (n = 1,910). All study subjects with acquired immunodeficiency syndrome were excluded from analyses. Our results showed that the risk of NHL is associated with a history of lymphoma (odds ratio [OR] = 3.0, 95 percent confidence interval [CI] = 1.7-5.2) and hematologic cancer (OR = 2.0, CI = 1.2-3.4) in first-degree relatives after adjustment for age, ethnic background, and educational level. Further analyses were performed for the subgroups defined by age at diagnosis (younger than 45 years cf 45 years or older). The association of NHL with a family history of lymphoma and hematologic cancer was found primarily among men aged 45 and older (OR = 4.1, CI = 1.9-8.8 for lymphoma and OR = 2.3, CI = 1.3-4.0 for hematologic cancer). The association among men aged 45 and older did not vary by whether or not there were any familial patients diagnosed at the age of 45 or older. No significant associations could be found for a family history of lung cancer, breast cancer, prostate cancer, colon cancer, skin cancer, liver cancer, stomach cancer, brain cancer, thyroid cancer, or myeloma. This study suggests that the familial risk of NHL is influenced primarily by hematolymphoproliferative malignancies rather than other cancers. The familial effects of hematolymphoproliferative malignancies may be stronger for men aged 45 to 59, compared with those aged 31 to 44.

Non-Hodgkin's lymphoma and family history of malignant tumors in a case-control study (United States)

Using data from a case-control study in the United States (the Selected Cancers Study), we examined the relationship between non-Hodgkin's lymphoma (NHL) and family history of different cancers. Cases were 1,511 men aged 31 to 59 years and diagnosed pathologically with non-Hodgkin's lymphoma during 1984-88. Controls were men, frequency-matched to cases by age range and cancer registry (n = 1,910). All study subjects with acquired immunodeficiency syndrome were excluded from analyses. Our results showed that the risk of NHL is associated with a history of lymphoma (odds ratio [OR] = 3.0, 95 percent confidence interval [CI] = 1.7-5.2) and hematologic cancer (OR = 2.0, CI = 1.2-3.4) in first-degree relatives after adjustment for age, ethnic background, and educational level. Further analyses were performed for the subgroups defined by age at diagnosis (younger than 45 years cf 45 years or older). The association of NHL with a family history of lymphoma and hematologic cancer was found primarily among men aged 45 and older (OR = 4.1, CI = 1.9-8.8 for lymphoma and OR = 2.3, CI = 1.3-4.0 for hematologic cancer). The association among men aged 45 and older did not vary by whether or not there were any familial patients diagnosed at the age of 45 or older. No significant associations could be found for a family history of lung cancer, breast cancer, prostate cancer, colon cancer, skin cancer, liver cancer, stomach cancer, brain cancer, thyroid cancer, or myeloma. This study suggests that the familial risk of NHL is influenced primarily by hematolymphoproliferative malignancies rather than other cancers. The familial effects of hematolymphoproliferative malignancies may be stronger for men aged 45 to 59, compared with those aged 31 to 44.

[Primary study on Fas-mediated apoptosis in the liver tissue of patients with chronic hepatitis B]

Apoptosis may be the cause of cell death that activate gene due to certain factors. It has been suggested that apoptosis is mediated through Fas antigen. To evaluate the role of the Fas antigen and apoptosis in chronic hepatitis B (CHB), we observed the Fas expression and nuclear DNA fragement in CHB hepatic tissue using immunohistochemistry and TUNEL method respectively. The results showed that the Fas antigen expressing cells located mainly in inflammation infiltrating area but less in non-inflammation infiltrating area; the positive cells were found particularly among infiltrating lymphocytes at the advancing edges of "piecemeal necrosis" near the portal regions. The expression of Fas was detected mainly in the cytoplasm of hepatocytes. 46 samples from 56 CHB patients were Fas positive, the posive rate reached 82%. The Linear Correlation and Regression analysis suggested that there was a direct correlation between nuclear DNA fragement and Fas expression. These findings suggest that the apoptosis mediated through Fas antigen may play an important role in pathogenesis of CHB.

A novel phospholipase A2 activity in saliva of the lone star tick, Amblyomma americanum (L.)

Saliva from female lone star ticks, Amblyomma americanum, contained a novel phospholipase A2 (PLA2) activity that hydrolyzed 14C-arachidonate from 14C-arachidonyl phosphatidylcholine. The tick saliva PLA2 (ts-PLA2) was active over a broad pH range (4.5-11.5) with two distinct pH optima of pH 5.5 and 9.5. Though extracellular PLA2s are reported to be activated by millimolar Ca2+, ts-PLA2 was sensitive to submicromolar Ca2+ and was half-maximally activated by 3.5 microM Ca2+. Tick saliva contains > 500 microM Ca2+ and the feeding lesion in the host is expected to contain millimolar Ca2+. Saliva exhibited a single peak of PLA2 activity corresponding to a molecular weight of 55.7 +/- 1.3 kDa by size exclusion chromatography. The ts-PLA2 was unaffected by a variety of compounds known to inhibit either secreted or cytosolic PLA2s from other sources. However, ts-PLA2 was inhibited by the substrate analog, oleyloxyethyl phosphorylcholine (IC50 = 1.4 microM), and the end product, arachidonic acid (IC50 = 38 microM). Low concentrations of dithiothreitol did not greatly affect ts-PLA2, but activity was reduced at higher concentrations. The PLA2 activity found in A. americanum salivary glands showed many similarities to ts-PLA2, but also some distinct differences. Secreted at the tick-host interface, ts-PLA2 is thought to play an important, but unknown, role during the prolonged tick feeding.

Isolation and characterization of americanin, a specific inhibitor of thrombin, from the salivary glands of the lone star tick Amblyomma americanum (L.)

A thrombin (EC 3.4.21.5) inhibitor (americanin) was isolated from the salivary glands of the lone star tick Amblyomma americanum (L.) using reversed-phase chromatography and anion-exchange chromatography. Americanin did not inhibit any other protease tested, including factor Xa, plasmin, trypsin, chymotrypsin, elastase, papain, pepsin, and carboxypeptidase. The inhibition of thrombin by americanin decreased dramatically with dilution of the reaction mixture including thrombin, its substrate, and americanin. When thrombin assays were performed in the presence of americanin, the reaction curve showed a time-dependent inhibition. Significant inhibition was observed when americanin concentration was approximately equal to that of thrombin, with a Ki of 0.073 nM. The results suggest that americanin is a specific, reversible, competitive, slow, tight-binding inhibitor of thrombin.

Estrogen receptor status of breast cancer: a marker of different stages of tumor or different entities of the disease?

Breast cancer can be divided into two types according to the estrogen receptor (ER) level of the tumor: ER-positive and ER-negative. Two hypotheses have been raised about the relationship between ER-positive and ER-negative breast tumors. One hypothesis considers ER status as an indicator of a different stage of the disease. The other regards ER-positive and ER-negative tumors as different entities. For both etiological and biological studies of breast cancer it is important to know which hypothesis is correct. In this paper, we review evidence for and against each hypothesis and suggest issues to be addressed in future studies.

Cigarette smoking and nasopharyngeal cancer: an analysis of the relationship according to age at starting smoking and age at diagnosis

To examine whether the association between smoking and nasopharyngeal cancer varies according to age at starting smoking and age at diagnosis of the disease, we compared 113 men with nasopharyngeal cancer diagnosed between 31 and 59 years old who lived within eight cancer registry areas to 1,910 controls selected by random-digit telephone dialing. Compared to smoking which began at the age of 22 years or older, the risk estimates were 0.4 (95% confidence interval (CI) 0.2-0.9) and 0.8 (95%CI 0.4-1.5) for smoking begun at the ages of 18-21 and 17 years or younger, when adjusted for pack-years smoked and other potential confounders (p for trend > 0.8). In contrast, the risk estimates adjusted for age at starting smoking and other variables were 1.3 (95%CI 0.7-2.6), 1.9(95%CI 0.9-4.0) and 3.0(95%CI 1.4-6.2) for 15-29.9, 30-44.9 and 45 or over, relative to 15 or less pack-years smoked (p for trend < 0.005). The analyses were repeated for subgroups in terms of age at diagnosis. The relative risks of ever-smoking and the dose-effect relation between pack-years and the risk of the disease were not significantly different between men whose cancer was diagnosed at the age 49 or younger and those whose tumor was diagnosed between the ages 50 and 59. This study suggests that the magnitude of the risk for nasopharyngeal cancer may not vary significantly with the age at which smoking begins, and age at which the disease is diagnosed.

The relationship of hepatitis history and pathological diagnosis of primary liver cancer

During the analysis of risk factors in relation to primary liver cancer, we noticed an association between the confirmed (as opposed to probable) pathologic diagnosis of liver cancer and a positive history of hepatitis. This report pursues the observation using data from the Selected Cancers Study. Study subjects included 168 men who lived in areas covered by eight cancer registries in the U.S., and were pathologically diagnosed with confirmed or probable primary liver cancer during 1984-1988. The results showed that men with confirmed primary liver cancer were six times more likely to have a hepatitis diagnosed within 3 years before liver cancer detection, compared with those with probable primary liver cancer. Further analyses showed that men with a confirmed primary liver cancer or with a recent hepatitis more likely had a tissue specimen obtained from a surgery, and less likely had one from an aspiration. Upon adjustment for type of specimen, the association between pathological confirmation of primary liver cancer and recent hepatitis persisted. The results raised questions whether recent hepatitis and its pathologic changes influence choice of tissue-collecting procedure and ultimate pathological diagnosis of primary liver cancer. Other factors that might be related to the findings also need to be examined in future studies.

Identification of hemolytic activity in saliva of the lone star tick (Acari:Ixodidae)

Hemolytic activity was identified in the saliva of Amblyomma americanum (L.) when red blood cells from sheep were incubated with tick saliva in the presence of phosphatidylcholine and sodium deoxycholate. The hemolytic activity was destroyed by boiling or treating with trypsin. The hemolytic activity in tick saliva was calcium-dependent, and inhibited by a phospholipase A2 inhibitor oleyloxyethyl phosphorylcholine. Phosphatidylserine could replace phosphatidylcholine in the hemolytic assays but phosphatidylethanolamine and phosphatidylinositol were ineffective. Size exclusion chromatography of tick saliva revealed one peak of hemolytic activity, which correlated with the activity of tick salivary phospholipase A2, both having a molecular weight approximately 55,000 daltons. These results suggest that the hemolytic activity in tick saliva results from salivary phospholipase A2. The hemolytic activity in tick saliva may play a role in lysing host red blood cells, thus facilitating the tick digestive process.

Identification and characterization of anticoagulant activities in the saliva of the lone star tick, Amblyomma americanum (L.)

Anticoagulant activities against both the extrinsic and intrinsic coagulation pathways were identified in the saliva of partially fed female lone star ticks, Amblyomma americanum (L.). The activities of factor Xa and thrombin in the common pathway of the coagulation cascade were inhibited by tick saliva. The greatest anticoagulant activities were found in the saliva of ticks weighing more than 200 mg. The anticoagulant activities in tick saliva could be detected without preincubation of tick saliva with sheep plasma, but preincubation significantly increased the activities. Tick saliva anticoagulant activities were abolished by boiling for 15 min or being treated with trypsin for 1 hr. Phosphatidylcholine (3 mM) and phospholipase A2 inhibitor oleyloxyethyl phosphorylcholine (0.2 mM) did not affect the anticoagulant activities significantly, suggesting that the phospholipase A2 activity found in tick saliva does not contribute to the anticoagulant activities. Size exclusion high performance liquid chromatography revealed that the molecular weights of the anticoagulant activities were approximately 16,000 D. The anticoagulant activities in tick saliva are believed to play an important role in facilitating tick feeding by helping overcome the host hemostatic system.

Vasectomy and prostate cancer: a case-control study in a health maintenance organization

A case-control study was conducted within Group Health Cooperative of Puget Sound to evaluate the relation between prior vasectomy and the risk of prostate cancer. Cases consisted of 175 men newly diagnosed with histologically confirmed prostate cancer during 1989-1991. A total of 258 controls, matched to cases on birth year and membership status, were randomly selected from the general membership of the plan. Information was collected from mailed questionnaires and medical records on medical history, including prior vasectomy, anthropometric measures, family history of prostate cancer, personal habits, and medical care utilization, and demographic factors. Conditional logistic regression analyses showed that the odds ratio for prostate cancer associated with vasectomy was 0.86 (95% confidence interval 0.57-1.32) after adjustment for confounders. The odds ratio estimate did not differ substantially by age at vasectomy or time since vasectomy. However, the odds ratio estimate for prostate cancer associated with vasectomy tended to be increased among men who had a father or brother with prostate cancer. Nevertheless, the increased risk may be related to detection bias or differential participation rates due to both vasectomy status and a family history of prostate cancer. These results suggest no overall association between vasectomy and prostate cancer.

[A study on red blood cell immune function in patients with Guillain-Barré syndrome and multiple sclerosis]

In order to understand whether there is red blood cell (RBC) immune dysfunction and the relationship between RBC immune abnormality and clinical state in patients with multiple sclerosis (MS) and Guillain-Barré syndrome (GBS), RBC immune function and circulation immune complex (CIC) level were evaluated in patient with these two diseases by using RBC immune adhesion test. It was found that the rate of formation of red blood cell-C3b receptor-yeast rosette was significantly lower in patients with these two diseases before and after treatment than that in a control group (P < 0.01). The rate of formation of red blood cell-immune complex-yeast rosette and the CIC level in GBS group were notably higher than that in the control group (P < 0.05). Moreover, we observed that the immune functions in patients with severe GBS and active MS were different from those in patients with mild GBS and stable MS and the change of each immune index in GBS and MS patients was related with the degree of recovery and the clinical state. These results suggested that decreased capability of RBC immune adhesion in patients with GBC and MS may be one of factors causing these diseases.

Identification of N-acetylglucosamine binding residues in Griffonia simplicifolia lectin II

Primary structure and crystallographic data of several legume lectins were used to predict the involvement in carbohydrate binding of six amino acid residues (Asp88, Glu108, Tyr134, Asn136, Leu226 and Gln227) in Griffonia simplicifolia lectin II (GS-II). The functional involvement of these residues was evaluated by assessing GlcNAc binding of modified forms of GS-II in which these residues were eliminated in truncated peptides or systematically substituted with other amino acids by site-specific mutations. Mutations at Asp88, Tyr134 or Asn136 eliminated GlcNAc binding activity by GS-II, while those at Glu108, Leu226 or Gln227 did not alter the activity. The former three amino acids were functionally essential for carbohydrate binding by GS-II presumably through hydrogen bonding to and hydrophobic interactions with GlcNAc. Although an Asp or Gly substitution for Tyr134 eliminated GlcNAc affinity, substitution with Phe did not appreciably affect binding. Despite the fact that mutations to Leu226 and Gln227 did not alter carbohydrate binding, a truncated form of GS-II lacking these residues no longer exhibited carbohydrate binding affinity.

An insecticidal N-acetylglucosamine-specific lectin gene from Griffonia simplicifolia (Leguminosae)

Griffonia simplicifolia II, an N-acetylglucosamine-specific legume lectin, has insecticidal activity when fed to the cowpea weevil, Callosobruchus maculatus (F.). A cDNA clone encoding G. simplicifolia II was isolated from a leaf cDNA library, sequenced, and expressed in a bacterial expression system. The recombinant protein exhibited N-acetylglucosamine-binding and insecticidal activity against cowpea weevil, indicating that glycosylation and multimeric structure are not required for these properties. These results support the hypothesis that genes of the legume lectin gene family encode proteins that function in plant defense against herbivores.

A population-based case-control study of the relationship between cigarette smoking and nasopharyngeal cancer (United States)

This case-control investigation, based on the Selected Cancers Study, assesses the association between cigarette smoking and nasopharyngeal cancer, a relatively rare neoplasm in the United States. Men who were diagnosed pathologically with nasopharyngeal cancer during 1984-88 were included as cases in the analysis if they were 15 to 39 years old in 1968, and lived in the areas covered by eight cancer registries in the US (n = 113). Control men were selected by random-digit telephone dialing (n = 1,910). Using logistic regression analysis with adjustment for potential confounding factors, it was found that relative to nonsmokers, the risks of nasopharyngeal cancer were 2.3 (95 percent confidence interval [CI] = 1.3-4.0) and 1.4 (CI = 0.8-2.6) for former and current smokers, respectively. Using pack-years as a measure, adjusted odds ratio (OR) estimates were 1.3, 1.8, 2.5, and 3.9 for smoking for less than 15, 15-29, 30-44, and 45 or more pack-years, respectively. When squamous cell carcinoma was used as an outcome, the smoking/nasopharyngeal-cancer association became stronger. The analysis did not show interactions between smoking and alcohol consumption, or prior nasal diseases. The results of this study suggest that cigarette smoking may be related to the occurrence of nasopharyngeal cancer (especially squamous cell carcinoma) among US men.

[Complications in multiple systems resulting from acute cerebrovascular diseases]

One hundred and eighty five patients died of acute cerebrovascular diseases with complications in multiple systems were studied. Statistical analyses showed that there were no organ and system failure (NOSF) in 47 cases, single organ and system failure (SOSF) in 47 and multiple organ and system failure (MOSF) in 91. Out of 90 (50%) cases who had cerebral herniation, 39 cases were complicated with SOSF and 53 cases with MOSF. Among the patients with acute brain diseases, 25% of them (46) died of SOSF (4%, 8 cases) and MOSF (21%, 38) without herniation. Incidence of failure of organ and system was higher with stomach, metabolism and lung than with heart, kidney and blood. It took on the average 24 and 12.5 hours for the first organ and system to fail and 4 days and 24 hours for the second organ in patients with intracranial hemorrhage and cerebral infarction. Occurrence of organ and system failure was closely related to sex, previous diseases and damage of brain stem, but not to the size and number of the lesion. It is suggested that cerebrogenic organ and system failure (COSF) or cerebrogenic multiple organ and system failure (CMOSF) be referred to functional failure of more than two organs or system not including brain itself as a result of acute brain diseases.

An association study between essential hypertension and HLA-DRB1 alleles

It is well established that genetic and environmental factors are involved in the etiology of essential hypertension (EH). Previous studies have suggested that at least one of the HLA genes is responsible for the genetic susceptibility to EH. Our aim in the present study was to investigate this issue in China by the PCR-SSP HLA-DRB1 typing method. The results showed an increased frequency of HLA-DR2 and a decreased frequency of HLA-DR7 with EH patients compared with controls. We consider that HLA-DR2 may represent a marker for susceptibility to EH in the North Chinese population.

Biosynthesis of salivary prostaglandins in the lone star tick, Amblyomma americanum

Dopamine-induced saliva from ticks fed [3H]arachidonic acid contained the radiolabelled prostaglandins E2, F2 alpha, D2, and B2, the latter probably derived from PGE2 owing to the alkalinity of tick saliva. Prostaglandin synthetase (PGS) activity in the salivary gland homogenate from the lone star tick, Amblyomma americanum, could not be detected by standard radiometric methodologies successfully employed for tissues from many animal species, including numerous arthropods. Modifications to the assay conditions had no effect. The presence of a PGS-inhibitor in the salivary glands was ruled out. It is postulated that the PGS in A. americanum salivary glands may be considerably different from that found in other animals, including vertebrate hosts.

Risk factors for preeclampsia in twin pregnancies: a population-based cohort study

OBJECTIVE

To evaluate in twin pregnancies the characteristics parity, race, smoking, and age, known to be risk factors for preeclampsia in non-twin pregnancies.

METHODS

All twin pregnancies (3407) and approximately twice as many singletons (8287) were assembled using Washington state birth certificates from the period 1984-1988.

RESULTS

In singleton pregnancies, preeclampsia was more common in women who were younger, black, poor, nulliparous, and nonsmokers. In twin pregnancies, similar associations were found, but were only statistically significant for age, race, and parity. There were no significant differences in the risk factors between twin and singleton women. Logistic regression showed that twin pregnancy carries a relative risk (RR) of 3.5 (95% confidence interval [CI] 3.0-4.2), nulliparity an RR of 4.0 (95% CI 3.3-4.8), and black race an RR of 1.8 (95% CI 1.2-2.6) for preeclampsia. In each case, this risk is independent of the other risk factors.

CONCLUSION

Twin pregnancy carries nearly a fourfold increased risk of preeclampsia, independent of race and parity, and the risk of a nulliparous twin pregnancy is 14 times that of a parous singleton pregnancy. Risk factors in a singleton pregnancy act similarly in a twin pregnancy. Thus, any pathophysiologic model for preeclampsia needs to account for the risk twin pregnancy poses as well as other risk factors, such as parity and race.