Enhanced wear performance of ultra high molecular weight polyethylene crosslinked by organosilane

Ultra high molecular weight polyethylene (UHMWPE) crosslinked by organosilane was thermal compression molded. The organosilane used was the tri-ethyloxyl vinyl silane. Its gelation, melting behavior, crystallinity, mechanical and wear-resisting properties were systematically investigated. The results showed that the gel ratio of UHMWPE increases with the incorporation of organosilane. At a low content of organosilane, the melting point and crystallinity of the crosslinked UHMWPE increase, and hence the mechanical and wear-resisting properties are improved. However, at a high content of organosilane, these performances of the crosslinked UHMWPE become worse. At 0.4 phr silane, the wear resistance of crosslinked UHMWPE reaches its optimum value.

Gene transfer and metabolic modulators as new therapies for pulmonary hypertension. Increasing expression and activity of potassium channels in rat and human models

Chronic Hypoxic Pulmonary Hypertension (CH-PHT) is characterized by pulmonary artery (PA) vasoconstriction and cell proliferation/hypertrophy. PA smooth muscle cell (PASMC) contractility and proliferation are controlled by cytosolic Ca++ levels, which are largely determined by membrane potential (E(M)). E(M) is depolarized in CH-PHT due to decreased expression and functional inhibition of several redox-regulated, 4-aminopyridine (4-AP) sensitive, voltage-gated K+ channels (Kv1.5 and Kv2.1). Humans with Pulmonary Arterial Hypertension (PAH) also have decreased PASMC expression of Kv1.5 and Kv2.1. We speculate this "K+-channelopathy" contributes to PASMC depolarization and Ca++ overload thus promoting vasoconstriction and PASMC proliferation. We hypothesized that restoration of Kv channel expression in PHT and might eventually be beneficial.

METHODS

Two strategies were used to increase Kv channel expression in PASMCs: oral administration of a metabolic modulator drug (Dichloroacetate, DCA) and direct Kv gene transfer using an adenovirus (Ad5-Kv2.1). DCA a pyruvate dehydrogenase kinase inhibitor, promotes a more oxidized redox state mimicking normoxia and previously has been noted to increase K+ current in myocytes. Rats were given DCA in the drinking water after the development of CH-PHT and hemodynamics were measured approximately 5 days later. We also tested the ability of Ad5-Kv2.1 to increase Kv2.1 channel expression and function in human PAs ex vivo.

RESULTS

The DCA-treated rats had decreased PVR, RVH and PA remodeling compared to the control CH-PHT rats (n=5/group, p<0.05). DCA restored Kv2.1 expression and PASMC Kv current density to near normoxic levels. Adenoviral gene transfer increased expression of Kv2.1 channels and enhanced 4-AP constriction in human PAs.

CONCLUSION

Increasing Kv channel function in PAs is feasible and might be beneficial.

Expression of lipopolysaccharide binding protein and its receptor CD14 in experimental alcoholic liver disease

AIM: To evaluate the relationship between the expression of lipopolysaccharides (LPS) binding protein (LBP) and CD14 mRNA and the severity of liver injury in alcohol-fed rats.

METHODS: Twenty Wistar rats were divided into two groups: ethanol-fed group (group E) and control group (group C). Group E was fed with ethanol (5-12 g·kg¯¹·d¯¹) and group C received dextrose instead of ethanol. Rats of the two groups were sacrificed at 4 wk and 8 wk. Levels of endotoxin and alanine transaminase (ALT) in blood were measured, and liver pathology was observed under light and electronic microscopy. Expressions of LBP and CD14 mRNA in liver tissues were determined by RT-PCR analysis.

RESULTS: Plasma endotoxin levels were increased more significantly in group E (129 ± 21) ng·L¯¹ and (187 ± 35) ng·L¯¹ at 4 and 8 wk than in control rats (48 ± 9) ng·L¯¹ and (53 ± 11) ng·L¯¹, respectively (P < 0.05). Mean values of plasma ALT levels were (1867 ± 250) nkat·L¯¹ and (2450 ± 367) nkat·L¯¹ in Group E. The values were increased more dramatically in ethanol-fed rats than in Group C after 4 and 8 wk. In liver section from ethanol-fed rats, there were marked pathological changes (steatosis, cell infiltration and necrosis). In ethanol-fed rats, ethanol administration led to a significant increase in LBP and CD14 mRNA levels compared with the control group (P < 0.05).

CONCLUSION: Ethanol administration led to a significant increase in endotoxin levels in serum and LBP and CD14 mRNA expressions in liver tissues. The increase of LBP and CD14 mRNA expression might wake the liver more sensitive to endotoxin and liver injury.

[The RAPD analysis of haploid strain of thermotolearnt yeast]

The haploid strains HZ line from the thermololeant strain HU-TY-1 of Saccharomyces cerevisiae have been obtained by sporulation, and the analysis of growth and fermentation test was performed. The strains HZ-21 and HZ-84 were used as the analysis of random amplified polymerphic DNA (RAPD). The result showed that there were some polymorphic DNA fragments of genomic DNA among haploid, the diploid parent strain HU-TY-1 and the original strain LK, some of them may be correlation with thermotolerant property.

Breast cancer: incidence, mortality, and early detection in Louisiana, 1988-1997

Breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer death among Louisiana women. The incidence data from Louisiana Tumor Registry were used to calculate breast cancer incidence rates, which were compared with the combined rates from the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program. Breast cancer mortality rates for Louisiana were compared with the US death rates from the National Center for Health Statistics (NCHS). Our data revealed that Louisiana women were not at a higher risk for developing breast cancer than women in the SEER areas, but that mortality rates in Louisiana were not correspondingly low. Although the percentage of cases diagnosed at an early stage (in situ and localized) increased in Louisiana from 1988 through 1997, the average in Louisiana was still below the level for the SEER areas (65.9% and 71.6%) in 1993-1997. The rates of in situ breast cancer significantly increased (on average 5.3% for whites per year and 7.1% for blacks), and localized breast cancer also significantly increased (2.6% for whites and 2.5% for blacks), while the incidence of distant stage breast cancer significantly decreased (3.4% for whites and 2.0% for blacks). Compared with white women, black women still were less likely to be diagnosed with early stage breast cancer in 1993-1997 (56.4% and 68.9%). Women residing in the parishes with high percentages of persons in poverty were less likely to be diagnosed with early stage of disease.

Calcium channel blockade in vascular smooth muscle cells: major hypotensive mechanism of S-petasin, a hypotensive sesquiterpene from Petasites formosanus

In vivo and in vitro studies were carried out to examine the putative hypotensive actions of S-petasin, a sesquiterpene extracted from the medicinal plant Petasites formosanus. Intravenous S-petasin (0.1-1.5 mg/kg) in anesthetized rats produced a dose-dependent hypotensive effect. In isolated aortic ring, isometric contraction elicited by KCl or the L-type Ca2+ channel agonist Bay K 8644 was reduced by S-petasin (0.1-100 microM), an action not affected by the cyclooxygenase inhibitor indomethacin, nitric-oxide synthase inhibitor N(omega)-nitro-L-arginine, guanylyl cyclase inhibitor methylene blue, or removal of vascular endothelium. Pretreatment with S-petasin for 10 min shifted the concentration-response curve for KCl (15-90 mM)-induced contraction to the right and reduced the maximal response. In Ca2+-depleted and high K+-depolarized aortic rings preincubation with S-petasin attenuated the Ca2+-induced contraction in a concentration-dependent manner, suggesting that S-petasin reduced Ca2+ influx into vascular smooth muscle cells (VSMCs). Moreover, in cultured VSMCs, whole-cell patch-clamp recording indicated that S-petasin (1-50 microM) inhibited the L-type voltage-dependent Ca2+ channel (VDCC) activities. Intracellular Ca2+ concentration ([Ca2+[(i)) estimation using the fluorescent probe 1-[2-(5-carboxyoxazol-2-yl)-6-aminobenzofuran-5-oxy]-2-(2'-amino-5'-methylphenoxy)-ethane-N,N,N,N-tetraacetic acid pentaacetoxymethyl ester indicated that S-petasin (10, 100 microM) suppressed the KCl-stimulated increase in ([Ca2+[(i)). Taken together, the results suggested that a direct Ca2+ antagonism of L-type VDCC in vascular smooth muscle may account, at least in part, for the hypotensive action of S-petasin.

Incidence of lymphohaematopoietic malignancies in a petrochemical industry cohort: 1983-94 follow up

OBJECTIVES

In response to a previous finding of increased mortality from lymphohaematopoietic (LH) malignancies, this study examines incidence of LH malignancy in a petrochemical industry cohort. Emphasis is on chronic lymphocytic leukaemia (CLL) and on comparisons by period of first employment.

METHOD

The study cohort consists of 8942 employees who were active in the period 1970-92 and alive on 31 December 1982. Record linkage with the Louisiana tumour registry (LTR) provided information on cancer for cases occurring between 1983 and 1994. Standardised incidence ratios (SIR), with the south Louisiana population as a comparison, were computed for all cancers, all LH malignancies and specific LH subtypes. Analyses were conducted for sex and race categories, and by period of first employment, job type, duration of employment, and latency.

RESULTS

672 Cases of cancer were identified, including 59 LH malignancies. Women (n=1169) had an overall cancer SIR below unity and four LH malignancies versus 2.28 expected. Among the 7773 men, those first employed before 1950 had no overall cancer excess, a significant 1.4-fold increase in overall LH malignancies (43 observed versus 30.78 expected), and four CLL cases versus 3.27 expected. Findings for men first employed after 1950 are based on fewer cases, but there was no indication of excesses of overall cancer or LH malignancy. Numbers were too small in the group first employed after 1950 for meaningful analysis of LH malignancy subtypes such as CLL (one case).

CONCLUSION

These findings do not suggest a continuing excess of CLL but do suggest a small increase in incidence of overall LH malignancy for workers first employed before 1950. This may reflect associations with earlier workplace conditions, although work related patterns are mixed. Interpretation is limited by the diverse group of diseases within LH malignancies, and the lack of control for non-work factors other than sex, age, race, and period of diagnosis. This study has a major advantage of more complete and reliable cancer ascertainment compared with the mortality investigation, and shows the feasibility and benefits of using cancer registry incidence data in an occupational cohort study.

[A quantitative analysis of renal pathology in the children with anaphylactoid purpura nephritis (APN)]

OBJECTIVE

To provide the theoretical value for the treatment and prognostic judgement of APN.

METHODS

All cases were scored on the pathologic change of glomeruli and tubules.

RESULTS

The pathologic scores of glomeruli in 30 cases were as follows: no one on Grade 0; 6(20%) on Grade 1; 17(56.7%) on Grade 2 and 7 (23.3%) on Grade 3. The pathologic scores of tubule were: Grade 0 was 2(6.7%); Grade 1 was 6(20%); Grade 2 was 14(46.7%); Grade 3 was 8(26.7%). There was positive correlation between glomerulus and tubule pathologic degree(r = 0.783, P < 0.01). The pathologic score of nephrotic syndrome in clinical manifestation was higher than that of non-nephrotic syndrome(P < 0.01). There was no significant difference in glomerular pathologic score between the simple urinary protein group and acute glomerulonephritis(AGN) group(P > 0.05), but tubular pathologic score in simple urinary proteins group was higher than that of AGN and essential hematuria group (P < 0.01, P < 0.05). The pathologic score of kidney(including glomerulus and tubule) was positively correlated with the disease course(r = 0.563, P < 0.01), but not with serum urea nitrogen and creatinine(r = 0.281, r = 0.236, P > 0.05).

CONCLUSION

Serious tubular pathologic changes(not only glomerular pathologic change, but also tubular pathologic change in the APN children) were found in the patients with nephrotic syndrome and simple urinary proteins. Long-term urinary protein and the recurrence of the disease may be the important risk factor in kidney pathologic of APN.

Mutations induced by some DNA minor groove binding alkylators in AS52 Chinese hamster cells

Nitrogen mustards are commonly used in cancer chemotherapy. They interact with DNA at electronegative sites, primarily forming N7 guanine mono-adducts and interstrand cross-links. Targeting nitrogen mustards to DNA by attachment of a DNA minor groove binding carrier such as the bisbenzimidazoles Hoechst 33258 (pibenzimol) or Hoechst 33342 (HOE) makes it possible to direct DNA alkylation to more specific stretches of DNA. We have performed a detailed molecular analysis of 6-thioguanine resistant clones arising in Chinese hamster AS52 cells after treatment with HOE, in comparison with a mono- and bifunctional pair of bisbenzimidazole-targeted nitrogen mustards (MGBs). HOE showed no significant ability to induce 6-thioguanine resistant mutants, possibly because drug-treated cells are highly susceptible to apoptosis within very short times. Neither of the MGBs caused the rapid cell death seen with the bisbenzimidazole. However, both MGBs were weaker mutagens than previously found for undirected mustards in the same system, an effect that we suggest could relate to greater structure-directed binding to less mutable DNA sites in the minor groove. Additionally, the nature of some of the mutants suggested there may be a small component of topo I and/or II-mediated events in the mutagenicity of the MGBs. Both MGBs showed high activity in causing deletion mutations, which may be due to errors in attempted repair of the complex lesions formed by minor groove targeted alkylators.

Role of erythropoietin and nitric oxide in modulating the tone of human renal interlobular and subcutaneous arteries from uraemic subjects

This study investigated potential reasons why erythropoietin (EPO) given therapeutically to patients with renal failure may increase peripheral, but not renal, vascular resistance. This was done by comparing the effects of EPO on resting tension in normal renal interlobular and subcutaneous vessels from uraemic patients. In human subcutaneous arteries from uraemic subjects, noradrenaline- and KCl-induced vasoconstrictions were enhanced when nitric oxide (NO) production was blocked with N(G)-nitro-L-arginine methyl ester (L-NAME), but were unaffected by EPO, while acetylcholine- and bradykinin-induced concentration-dependent relaxations were markedly attenuated by L-NAME, but not by EPO. The noradrenaline- and KCl-induced vasoconstrictions of human renal interlobular arteries were unaffected by the presence of L-NAME, but were attenuated by EPO (20 units.ml(-1)) by some 33% (P<0.01); this effect was enhanced by the co-administration of L-NAME. Acetylcholine and bradykinin caused comparable dilatations of the interlobular arteries; the response to the former was attenuated by L-NAME, but none of these responses were changed by EPO. EPO given alone, at a concentration of either 0.1 or 20 units.ml(-1), had no effect on basal resting tone. NO production mediated both acetylcholine- and bradykinin-induced relaxation in this vessel type. In contrast, in the interlobular arteries there was no indication of NO modulating the level of vasoconstriction, and it only mediated acetylcholine-induced dilation. These acute responses to EPO only partially explain its differential effects on the vasculature in renal failure.

Relationship between erythropoietin and nitric oxide in the contraction of rat renal arcuate arteries and human umbilical vein endothelial cells

We have investigated the effects of recombinant human erythropoietin (EPO) on the responses of rat renal arcuate arteries to dopamine, noradrenaline and acetylcholine and on the release of NO from human umbilical vein endothelial cells (HUVEC) in culture. Noradrenaline induced a concentration-dependent constriction and acetylcholine a concentration-dependent relaxation of the vessels. The effects of dopamine were concentration-dependent, leading to relaxation of the vessels at low concentrations and contraction of the vessels at high concentrations. N(G)-Nitro-L-arginine methyl ester (L-NAME; 0.1 mM) did not change the vasoconstrictor responses to noradrenaline and dopamine, but inhibited the acetylcholine- and dopamine-induced vasorelaxation. Neither 0.1 nor 20 units.ml(-1) EPO affected noradrenaline-induced constriction, or dopamine- or acetylcholine-induced relaxation, of the vessels. EPO at 20 units. ml(-1) attenuated dopamine-induced constriction of the vessels. This effect was blunted by application of L-NAME, suggesting that EPO may stimulate dopamine-mediated NO release from these vessels. EPO stimulated NO release from the resting HUVEC in a concentration- and time-dependent manner, an effect that was inhibited by the presence of N(G)-nitro-L-arginine. These data suggest that, in vitro, EPO is able to stimulate NO release from rat renal arcuate arteries and HUVEC in culture. Whether these acute short-term actions can be related to the longer-term actions of EPO remains to be resolved.

Nitric oxide and renal nerve-mediated proximal tubular reabsorption in normotensive and hypertensive rats

In Inactin-anesthetized Wistar rats with an intact renal innervation, intratubular nitro-L-arginine methyl ester (L-NAME, 10(-4) M) increased proximal fluid uptake (J(va), at 2.47 +/- 0.61 x 10(-4) mm(3). mm(-2). s(-1)) by 17% (P < 0.05), whereas coadministration with sodium nitroprusside (SNP, 10(-4) M) decreased J(va) by 18% (P < 0.01). Similar manipulation of NO generation was without effect in groups of Wistar rats subjected to acute renal denervation. Intratubular aminoguanidine (10(-4) M), a selective inducible nitric oxide synthase (NOS) blocker, had no effect on J(va) in intact kidneys of Wistar rats, but the neuronal NOS (nNOS) blocker, 7-nitroindazole (10(-4) M and 10(-6) M) increased J(va) by 19-23% (both P < 0.001). In stroke-prone spontaneously hypertensive rats (SHRSP), J(va) values in the innervated kidneys were lower (P < 0.05) than in the corresponding Wistar groups and were unchanged by intratubular L-NAME or L-NAME plus SNP. The tonic attenuation of proximal epithelial transport by NO was dependent on the renal sympathetic nerves and appeared to be generated by the nNOS isoform of the enzyme. This role of NO was not evident in the SHRSP.

The influence of erythropoietin on the vascular responses of rat resistance arteries

This study examined the effect of erythropoietin (EPO) on resting tension and on the responses of rat mesenteric and renal arcuate arteries in vitro to a number of agonists as a possible cause of its blood pressure elevating properties when used therapeutically. Noradrenaline and potassium chloride induced concentration-dependent vasoconstrictions in both vessel types but the basal tension, maximum tension, and the -log concentration producing half-maximal response (pEC50) were altered in the presence of 0.1 or 20 U ml-1 EPO. The thromboxane A2 receptor agonist U46619 induced a constriction of the renal arcuate arteries which was enhanced by EPO at 20 U ml-1, from 1.68 +/- 0.34 to 2.64 +/- 0.39 mN mm-1 (P < 0.01), but which was unchanged by NG-nitro-L-arginine methyl ester (10-4 m). Serotonin (10-9-10-5 M) caused a concentration-related vasoconstriction in renal arcuate arteries which was shifted to the right in the time control study (P < 0.001) but this was abolished by both 0.1 and 20 U ml-1 of EPO. Acetylcholine induced a relaxation of precontracted mesenteric arteries, by 95.4 +/- 1.64 % with an EC50 of 7.08 +/- 0.08 M which was reduced (P < 0.001) by 20 U ml-1 EPO to 81.7 +/- 3.56 % and 6.10 +/- 0.11 M, respectively. The sodium nitroprusside-induced relaxations were unaffected by EPO. The acetylcholine-mediated relaxations in renal arcuate arteries were unchanged by EPO. Bradykinin-induced relaxations in mesenteric and renal arcuate arteries were unaffected by both EPO concentrations. Together these data showed that EPO over a large concentration range had only minor effects on basal tension and the vascular responsiveness of both mesenteric and renal arcuate arteries. The mechanism whereby EPO causes a chronic elevation in blood pressure is unlikely to be due to acute interactions with agonist-mediated responses.

Vasorelaxing action of rutaecarpine: effects of rutaecarpine on calcium channel activities in vascular endothelial and smooth muscle cells

Rutaecarpine (Rut) has been shown to induce hypotension and vasorelaxation. In vitro studies indicated that the vasorelaxant effect of Rut was largely endothelium-dependent. We previously reported that Rut increased intracellular Ca2+ concentrations ([Ca2+]i) in cultured rat endothelial cells (ECs) and decreased [Ca2+]i in cultured rat vascular smooth muscle (VSMCs) cells. The present results showed that the hypotensive effect of Rut (10-100 microgram/kg i.v.) was significantly blocked by the nitric oxide synthase inhibitor Nomega-nitro-L-arginine. In aortic rings, Rut (0. 1-3.0 microM)-induced vasorelaxation was inhibited by Nomega-nitro-L-arginine and hydroquinone but not by antagonists of the various K+ channels, 4-aminopyridine, apamin, charybdotoxin, or glibenclamide. Rut (0.1 and 1.0 microM) inhibited the norepinephrine-induced contraction generated by Ca2+ influx and at 1.0 microM increased cyclic GMP (cGMP) production in endothelium-intact rings and to a lesser extent in endothelium-denuded rings. In whole-cell patch-clamp recording, nonvoltage-dependent Ca2+ channels were recorded in ECs and Rut (0.1, 1.0 microM) elicited an opening of such channels. However, in VSMCs, Rut (10.0 microM) inhibited significantly the L-type voltage-dependent Ca2+ channels. In ECs cells, Rut (1.0, 10.0 microM) increased nitric oxide release in a Ca2+-dependent manner. Taken together, the results suggested that Rut lowered blood pressure by mainly activating the endothelial Ca2+-nitric oxide-cGMP pathway to reduce smooth muscle tone. Although the contribution seemed to be minor in nature, inhibition of contractile response in VSMCs, as evidenced by inhibition of Ca2+ currents, was also involved. Potassium channels, on the other hand, had no apparent roles.

Louisiana Tumor Registry: new developments and activities

New developments in the Louisiana Tumor Registry (LTR) over the past 3 years have enhanced the operation of the LTR and broadened its functions. Recent funding for numerous special studies and research collaborations have expanded the registry activities from data collection and special etiologic studies to more completely address the mandates of registry law, which require the LTR to participate in studies of cancer causes, treatment, and survival in order to reduce cancer morbidity and mortality in Louisiana.

Cancer of the colon and rectum in Louisiana

Cancer of the colon and rectum ranks fourth for incidence and second for mortality among Louisiana residents. Incidence rates calculated from Louisiana Tumor Registry data for 1991-95 show that whites in Louisiana were diagnosed with colon cancer at approximately the same rates as those in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program, but rates for African Americans were significantly lower in Louisiana than nationally. For rectal cancer, Louisiana incidence rates approximate the national rates for all but African-American males, whose rate was significantly lower. Mortality rates for colon and rectal cancer in Louisiana were comparable to the SEER rates, suggesting Louisiana blacks, once diagnosed, have a poorer survival than their national counterparts. Risk factors for colorectal cancer and guidelines for screening are discussed, as is an upcoming study of patient care for colon cancer.

Enhanced secretory production of a single-chain antibody fragment from Bacillus subtilis by coproduction of molecular chaperones

Formation of inclusion bodies is a major limiting factor for secretory production of an antidigoxin single-chain antibody (SCA) fragment from Bacillus subtilis. To address this problem, three new strains with enhanced production of molecular chaperones were constructed. WB600BHM constitutively produces the major intracellular molecular chaperones in an appropriate ratio without any heat shock treatment. This strain reduced the formation of insoluble SCA by 45% and increased the secretory production yield by 60%. The second strain, WB600B[pEPP], overproduces an extracytoplasmic molecular chaperone, PrsA. An increase in the total yield of SCA was observed. The third strain, WB600BHM[pEPP], coproduces both intracellular and extracytoplasmic molecular chaperones. This led to a further reduction in inclusion body formation and a 2.5-fold increase in the secretory production yield. SCA fragments secreted by this strain were biologically active and showed affinity to digoxin comparable to the affinity of those secreted by strains without overproduction of molecular chaperones. Interestingly, accumulation of a pool of periplasmic SCA was observed in the PrsA-overproducing strains. This pool is suggested to represent the secreted folding intermediates in the process of achieving their final configuration.

Cancer incidence in the industrial corridor: an update

Because of the high density of industries along the Lower Mississippi River, there is a concern about adverse impact on health, including cancer, among residents in these parishes. This study provides an update of cancer incidence in the Industrial Corridor for the period 1989-93. Age-adjusted cancer incidence rates were calculated for the seven-parish study area from Baton Rouge down to, but not including, New Orleans. Rates were also computed for the entire state of Louisiana and for the combined Surveillance, Epidemiology and End Results (SEER) program. Cancer incidence rates for the Industrial Corridor are either similar to, or lower than, the combined SEER rates for most of the common cancers as well as for rare tumors. The only two exceptions are lung cancer in white males and kidney cancer in white females that are significantly elevated when compared to the SEER averages. Significantly lower rates are found among white males for cancers of kidney, brain, and nervous system, and melanoma; among black males, cancers of all sites combined, oral cavity, stomach, rectum, and prostate, Hodgkin's disease, and non-Hodgkin's lymphoma; among white females, cancers of all sites combined, cervix, uterine corpus, ovary, bladder, and melanoma; and among black females, cancers of all sites combined, oral cavity, lung, breast, ovary, and melanoma. The persistent excess of lung cancer has led to the development of a multi-agency project to evaluate the impact of potential environmental exposures, genetic susceptibility, and their interactions on lung cancer risk. The findings also confirm the urgent need to include and strengthen tobacco prevention and cessation programs in our cancer control activities.

Engineering of plasmin-resistant forms of streptokinase and their production in Bacillus subtilis: streptokinase with longer functional half-life

The short in vivo half-life of streptokinase limits its efficacy as an efficient blood clot-dissolving agent. During the clot-dissolving process, streptokinase is processed to smaller intermediates by plasmin. Two of the major processing sites are Lys59 and Lys386. We engineered two versions of streptokinase with either one of the lysine residues changed to glutamine and a third version with both mutations. These mutant streptokinase proteins (muteins) were produced by secretion with the protease-deficient Bacillus subtilis WB600 as the host. The purified muteins retained comparable kinetics parameters in plasminogen activation and showed different degrees of resistance to plasmin depending on the nature of the mutation. Muteins with double mutations had half-lives that were extended 21-fold when assayed in a 1:1 molar ratio with plasminogen in vitro and showed better plasminogen activation activity with time in the radial caseinolysis assay. This study indicates that plasmin-mediated processing leads to the inactivation of streptokinase and is not required to convert streptokinase to its active form. Plasmin-resistant forms of streptokinase can be engineered without affecting their activity, and blockage of the N-terminal cleavage site is essential to generate engineered streptokinase with a longer in vitro functional half-life.

Aggressiveness of colon carcinoma in blacks and whites. National Cancer Institute Black/White Cancer Survival Study Group

Black patients with colon cancer in the Black/White Cancer Survival Study were found to have a poorer survival than white patients. More advanced-stage disease at diagnosis was the primary determinant, accounting for 60% of the excess mortality. After adjusting for stage, factors such as poverty, other socioeconomic conditions, and treatment did not further explain the remaining survival deficit. This study examined the aggressiveness of colon tumors in blacks and whites to explore its role in the racial survival differences. Tumor characteristics of 703 cases of newly diagnosed invasive colon adenocarcinoma were centrally evaluated by a gastrointestinal pathologist, blinded in regard to the age, race, and sex of the patients. Blacks were less likely to have poorly differentiated (grade 3) tumors [odds ratio (OR), 0.44; 95% confidence interval, 0.22-0.88] and lymphoid reaction (OR, 0.49; 95% confidence interval, 0.26-0.90) when compared with whites. These black/white (B/W) differences remained statistically significant after adjusting for age, sex, metropolitan area, summary stage, socioeconomic status, body mass index, and health care access and utilization. In addition, blacks were less likely to have high-grade (grade 3) nuclear atypia, mitotic activity, and tubule formation, although these ORs did not reach a statistical significance level of 0.05. Similar B/W differences were observed for patients with advanced disease but not with early stage. Comparison by anatomical subsite showed that blacks had statistically significantly better differentiated tumors for cancers of the proximal and transverse colon but not for the distal. No racial differences were found for blood vessel and lymphatic invasion, necrosis, fibrosis, and mucinous type of histology. The findings, therefore, are the opposite of those hypothesized. After adjusting for stage, more aggressive tumor characteristics do not explain the adverse survival differential in blacks. This suggests that there may be racial differences in environmental exposure, and that the intensity and mode of delivery of carcinogen insult as well as host susceptibility may differ by race and anatomical subsite. Future studies should explore the B/W differences in tumor biology using molecular markers that precede the conventional histological parameters evaluated here.

Highlights of cancer incidence in Louisiana, 1988-1992

This paper highlights the major findings from the recently released volume of the Louisiana Tumor Registry monograph series: Cancer Incidence in Louisiana, 1988-1992. One out of three Louisiana residents will develop cancer in his or her lifetime. Lung cancer remains the most common cancer for all races, both genders combined. Lung cancer rates for women continue to rise substantially (20% over the previous 5-year period) and African-American men in the Acadiana Region have the state's highest lung cancer rate. The number of prostate cancer cases has surpassed that of lung cancer for the first time in Louisiana men; the sizable increase since 1983 (about 50%) in prostate cancer likely reflects the recent aggressive screening by the PSA test. Breast cancer remains the most common cancer among Louisiana women and incidence rates have increased about 20% over the previous 5-year period. Geographic comparisons show that the New Orleans Region continues to have rates higher than state averages, and a clear pattern of high cancer risk has emerged for the Acadiana region. The Central Louisiana and the Baton Rouge Regions have rates lower than state averages.

Patterns of DNA ploidy and S-phase fraction associated with breast cancer survival in blacks and whites

A significant survival difference between black and white breast cancer patients has been observed in the United States. Evaluation of the prognostic value of DNA ploidy and S-phase fraction (SPF) in black and white breast cancer patients may contribute to our understanding of the mechanisms of racial disparity in survival. A sample of 98 patients (50 blacks and 48 whites) who participated in the Black/White Cancer Survival Study was selected for DNA flow cytometry analysis. Patients were followed between 4.5 and 6.5 years. The impacts of DNA ploidy and SPF on breast cancer survival were examined. Kaplan-Meier survival curves, log rank statistics, and Cox proportional hazards regression were used for survival analyses. Black patients were more likely than white patients to have tumors with high SPF (P < 0.05), but there was no difference in DNA ploidy (P = 0.79). Because there were significant interactions of both DNA ploidy and SPF with race, survival was examined separately for blacks and whites. Significantly poorer survival was observed for white patients with class A ploidy (hypodiploidy, hypotetraploidy, and hypertetraploidy; P = 0.001) and with high SPF (P = 0.025). The elevated hazard ratios remained significant after adjusting for age and stage. Further adjustment for adjuvant therapy and histopathological characteristics of tumor reduced the hazard ratios of SPF to a nonsignificant level. No significant associations were found between survival and DNA ploidy or SPF among blacks. DNA ploidy and SPF are prognostic factors for breast cancer survival in white patients but not in blacks. This may have clinical implication in breast cancer management.

Racial comparison of p53 alterations in breast cancer: difference in prognostic value

A significant difference in breast cancer survival between blacks and whites has been observed in the United States. Biological variation between races has been suggested to explain the difference. We investigated the difference by comparing the prognostic value of p53 alterations (mutations and protein accumulation) between black and white breast cancer patients. Black, but not white, patients with p53 mutations had a significantly poorer survival than those without p53 mutations (p < 0.05). In contrast, white, but not black, patients having tumors with p53 protein accumulation tended to have a poorer survival than those without accumulation of p53 protein (p = 0.058). Among patients who died of breast cancer, blacks were often to have p53 mutations without protein accumulation, and whites frequently had p53 protein accumulation without mutations. The racial disparities in the associations of p53 alterations with breast cancer survival could have clinical implications in terms of treatment management.

[Clinical and experimental study on sustained release tablet of Tripterygium wilfordii in treating rheumatoid arthritis]

Adopt to the prospective, multi-center, random, single-blind, equal rank-control methods, 226 patients of rheumatoid arthritis diagnosed according to the ARA criteria, were divided into 2 groups. One hundred and fourteen patients of test group were treated with sustained release tablets of Tripterygium wilfordii (TW-SR) orally, 2 tablets, twice a day for 4 weeks, 112 patients of control group received tablets of Tripterygium wilfordii (TW) orally, 2 tablets 3 times per day for 4 weeks. Results showed that the total effective rate of the two groups were 92.11% and 90.65%, respectively (P > 0.05). The adverse reaction rate of TW-SR group was 20.18%, which was lowered than that of TW group (70.54%, P < 0.01). Results of pre-clinical pharmacologic experimental study showed that the TW-SR has obvious anti-inflammatory, analgesia and immunosuppress'ive action as the TW has, while its toxicity was less than the latter significantly.