The Green Operating Room: Simple Changes to Reduce Cost and Our Carbon Footprint

Generating over four billion pounds of waste each year, the healthcare system in the United States is the second largest contributor of trash with one-third produced by operating rooms. Our objective is to assess improvement in waste reduction and recycling after implementation of a Green Operating Room Committee (GORC) at our institution. A surgeon and nurse-initiated GORC was formed with members from corporate leadership, nursing, anesthesia, and OR staff. Initiatives for recycling opportunities, reduction of energy and water use as well as solid waste were implemented and the results were recorded. Since formation of GORC in 2008, our OR has diverted 6.5 tons of medical waste. An effort to recycle all single-use devices was implemented with annual solid waste reduction of approximately 12,860 lbs. Disposable OR foam padding was replaced with reusable gel pads at greater than $50,000 per year savings. Over 500 lbs of previously discarded batteries were salvaged from the OR and donated to charity or redistributed in the hospital ($9,000 annual savings). A “Power Down” initiative to turn off all anesthesia and OR lights and equipment not in use resulted in saving $33,000 and 234.3 metric tons of CO2 emissions reduced per year. Converting from soap to alcohol-based waterless scrub demonstrated a potential saving of 2.7 million liters of water annually. Formation of an OR committee dedicated to ecological initiatives can provide a significant opportunity to improve health care's impact on the environment and save money.

The green operating room: simple changes to reduce cost and our carbon footprint

Generating over four billion pounds of waste each year, the healthcare system in the United States is the second largest contributor of trash with one-third produced by operating rooms. Our objective is to assess improvement in waste reduction and recycling after implementation of a Green Operating Room Committee (GORC) at our institution. A surgeon and nurse-initiated GORC was formed with members from corporate leadership, nursing, anesthesia, and OR staff. Initiatives for recycling opportunities, reduction of energy and water use as well as solid waste were implemented and the results were recorded. Since formation of GORC in 2008, our OR has diverted 6.5 tons of medical waste. An effort to recycle all single-use devices was implemented with annual solid waste reduction of approximately 12,860 lbs. Disposable OR foam padding was replaced with reusable gel pads at greater than $50,000 per year savings. Over 500 lbs of previously discarded batteries were salvaged from the OR and donated to charity or redistributed in the hospital ($9,000 annual savings). A "Power Down" initiative to turn off all anesthesia and OR lights and equipment not in use resulted in saving $33,000 and 234.3 metric tons of CO2 emissions reduced per year. Converting from soap to alcohol-based waterless scrub demonstrated a potential saving of 2.7 million liters of water annually. Formation of an OR committee dedicated to ecological initiatives can provide a significant opportunity to improve health care's impact on the environment and save money.

Complementary and alternative therapies among very long-term breast cancer survivors

Breast cancer patients may have different complementary and alternative medicine (CAM) usage rates and may turn to CAM for different reasons than healthy adults. CAM has mostly been studied in recently diagnosed women; no studies have included survivors 10 years post-diagnosis. We examined very long-term breast cancer survivors to determine whether CAM users had dissimilar patterns of association with survivorship factors. Interviews of 374 breast cancer case patients from a population-based case-control breast cancer study of young women from Los Angeles County, California, during the 1980s occurred at follow-up; 371 patients with complete information were included. CAM represented 28 herbal remedies. Quality-of-life originated from the Medical Outcomes Study Short Form 36 questionnaire (SF-36). Higher rates of CAM (59%) usage occurred compared to nationwide estimates. CAM users resembled non-users on follow-up age, exercise, original disease, treatment, smoking, body-mass index, alcohol, and fear of recurrence. CAM users had a higher prevalence of medical co-morbidities (P = 0.0005), and scored significantly lower on the SF-36 emotional well-being subscale than non-CAM users (P = 0.01). CAM users and non-users did not differ on the SF-36 physical sub-scale. Very long-term breast cancer survivors who use CAM may have poorer emotional functioning and more medical problems than non-users.

Btk-dependent regulation of phosphoinositide synthesis

Activation of the BCR (B cell antigen receptor) stimulates the production of both PtdIns(3,4,5) P3 and Ins(1,4,5) P3. PtdIns(3,4,5) P3 and Ins(1,4,5) P3 are generated from a common substrate, PtdIns(4,5) P2. In some systems, continuous PtdIns(4,5) P2 synthesis is necessary for maximal Ins(1,4,5) P3 production, but whether this is true for the BCR, and whether PtdIns(4,5) P2 synthesis is regulated following BCR activation, are not known. We found that Btk (Bruton's tyrosine kinase), a member of the Tec family of cytoplasmic protein tyrosine kinases, is constitutively associated with PIP5Ks (phosphatidylinositol 4-phosphate 5-kinases), the enzymes that synthesize PtdIns(4,5) P2. Btk functions as a shuttle to bring PIP5K to the plasma membrane as a means of stimulating PtdIns(4,5) P2 synthesis. The Btk-PIP5K complex appears to localize to lipid rafts. This complex provides a novel shuttling mechanism that allows Btk to regulate the production of the substrate required by both its upstream activator phosphoinositide 3-kinase and its downstream target phospholipase Cgamma2.

LKB1 associates with Brg1 and is necessary for Brg1-induced growth arrest

Inactivating mutations in the serine-threonine kinase LKB1 (STK11) are found in most patients with Peutz-Jeghers syndrome; however the function of LKB1 is unknown. We found that LKB1 binds to and regulates brahma-related gene 1 (Brg1), an essential component of chromatin remodeling complexes. The association requires the N terminus of LKB1 and the helicase domain of Brg1 and LKB1 stimulates the ATPase activity of Brg1. Brg1 expression in SW13 cells induces the formation of flat cells indicative of cell cycle arrest and senescence. Expression of a kinase-dead mutant of LKB1, SL26, in SW13 cells blocks the formation of Brg1-induced flat cells, indicating that LKB1 is required for Brg1-dependent growth arrest. The inability of mutants of LKB1 to mediate Brg1-dependent growth arrest may explain the manifestations of Peutz-Jeghers syndrome.

Vav2 is required for cell spreading

Vav2 is a widely expressed Rho family guanine nucleotide exchange factor highly homologous to Vav1 and Vav3. Activated versions of Vav2 are transforming, but the normal function of Vav2 and how it is regulated are not known. We investigated the pathways that regulate Vav2 exchange activity in vivo and characterized its function. Overexpression of Vav2 activates Rac as assessed by both direct measurement of Rac-GTP and cell morphology. Vav2 also catalyzes exchange for RhoA, but does not cause morphologic changes indicative of RhoA activation. Vav2 nucleotide exchange is Src-dependent in vivo, since the coexpression of Vav2 and dominant negative Src, or treatment with the Src inhibitor PP2, blocks both Vav2-dependent Rac activation and lamellipodia formation. A mutation in the pleckstrin homology (PH) domain eliminates exchange activity and this construct does not induce lamellipodia, indicating the PH domain is necessary to catalyze nucleotide exchange. To further investigate the function of Vav2, we mutated the dbl homology (DH) domain and asked whether this mutant would function as a dominant negative to block Rac-dependent events. Studies using this mutant indicate that Vav2 is not necessary for platelet-derived growth factor- or epidermal growth factor-dependent activation of Rac. The Vav2 DH mutant did act as a dominant negative to inhibit spreading of NIH3T3 cells on fibronectin, specifically by blocking lamellipodia formation. These findings indicate that in fibroblasts Vav2 is necessary for integrin, but not growth factor-dependent activation of Rac leading to lamellipodia.

Blunt chest trauma in the elderly patient: how cardiopulmonary disease affects outcome

Blunt trauma patients with rib fractures have significant risk of morbidity and mortality. The risk of complications increases with age and cardiopulmonary disease. We reviewed our experience at a community hospital Level II trauma center over a 5-year period. A review of the trauma registry revealed 62 patients over the age of 65 with multiple rib fractures and no associated injuries. Thirty-one patients with cardiopulmonary disease (CPD+) were compared with 31 patients without cardiopulmonary disease (CPD-). Charts were reviewed for morbidity, mortality, the need to upgrade level of care (readmission to the hospital or intensive care unit), and length of hospitalization. Complications occurred in 17 of 31 CPD+ patients and in four of 31 CPD- patients (P < 0.001). The only three deaths were in CPD+ patients. Ten CPD+ patients and four CPD- patients required an upgrade in the level of care (P < 0.05). The CPD+ patients had longer hospitalization than the CPD- patients: 8.5 versus 4.3 days (P < 0.05). We conclude that elderly patients with multiple rib fractures and cardiopulmonary disease are at significant risk for complications that result in readmission to the hospital and intensive care unit and prolonged length of hospitalization. Admission to the intensive care unit with attention to cardiac and pulmonary status upon transfer to the ward is warranted.

Body size, physical activity, and breast cancer hormone receptor status: results from two case-control studies

We evaluated whether our previous reports of increased postmenopausal breast cancer risk with higher body mass index (BMI) or of reduced premenopausal and postmenopausal breast cancer risk with higher physical activity levels varied according to the tumor's estrogen receptor (ER) and progesterone receptor (PR) status. Participants enrolled in either of two population-based case-control studies in Los Angeles County, California: one of premenopausal women (ages < or = 40 years), and one of postmenopausal women (ages 55-64 years). Case participants were diagnosed for the first time with in situ or invasive breast cancer from 7/1/83 through 12/31/88 (premenopausal women) or from 3/1/87 through 12/31/89 (postmenopausal women). Joint ER/PR status was collected for 424 premenopausal and 760 postmenopausal case participants. The analysis included 714 premenopausal and 1091 postmenopausal age-matched, race-matched (white or Hispanic), parity-matched (premenopausal women only), and residential neighborhood-matched control participants. Among the postmenopausal women, obesity was associated with an increased odds of ER+/PR+ breast cancer (odds ratio, 2.45 for women in the highest versus the lowest body mass index quartile; 95% confidence interval, 1.73-3.47). Body mass index was associated with neither ER-/PR- tumors among the postmenopausal women nor with any ER/PR subgroup among the premenopausal women. For both premenopausal and postmenopausal women, higher recreational physical activity levels (> or = 17.6 MET-hours/week versus no activity) were associated with a 30-60% reduction in risk of nearly all ER/PR subtypes, although the associations were generally of borderline statistical significance. Examining these potentially modifiable breast cancer risk factors by tumor ER and PR status may provide us with greater insight into breast cancer etiology and the mechanisms underlying the risk factor associations.

Joint segregation and linkage analysis of a quantitative trait compared to separate analyses

Our goal was to determine the degree to which joint segregation and linkage analysis leads to increased efficiency for estimating the recombination fraction and to greater power for detecting linkage, compared to separate analyses. We concentrated on the quantitative phenotype Q2 and analyzed linkage with a tightly linked marker, a loosely linked marker, and eight unlinked markers, the latter chosen to evaluate false positive rates. We considered both nuclear-family and extended-pedigree data, using the 200 replicates of each provided to GAW participants. We found joint analysis to be consistently more efficient, with relative efficiencies for the tightly linked marker of 1.16 and 1.06 in extended pedigrees and nuclear families, respectively. These relative efficiencies translated into modest but consistent gains in power to detect linkage. Both methods appear to produce unbiased parameter estimates and similar false positive rates.

Analysis of gene-smoking interaction in lung cancer

The Louisiana Lung Cancer Dataset, consisting of 337 extended pedigrees, is analyzed to determine whether a major Mendelian gene interacts with cumulative tobacco smoking (pack-years). The proportional hazards model is utilized, as it is a natural framework for estimating relative risks while adjusting for variability in age of disease onset. Segregation analyses show evidence that a Mendelian gene is segregating in these families, with the most parsimonious model, including sex, pack-years, pack-years squared, and a dominant major gene. The estimated frequency of the high-risk allele is 2% and carriers are estimated to have relative risk of 17.3 for developing lung cancer, compared to noncarriers. The addition of a gene x pack-years interaction does not significantly improve the fit of the model, indicating that on a multiplicative scale, these two factors independently influence lung cancer risk. Smoking history is missing for 23% of the study subjects and degree of "missingness" depends on disease status, age, and birth-year. To account for the nonrandomness of the missing data, a Markov chain Monte Carlo method for covariate imputation is proposed and implemented. Results from this analysis also support a nonsignificant gene-smoking interaction and an allele frequency of 2%, but a lower genetic relative risk (9.0) compared to the "complete case" analysis.

Actin cytoskeleton and cell signaling

The role of the actin cytoskeleton in the function of eukaryotic cells is ubiquitous. Regulation of actin polymerization allows cells to control their shape, to move, divide, secrete, and phagocytose. Actin filaments provide strength, connections to other cells and the extracellular matrix, paths for intracellular transport and a scaffold for generating force. Recently, a number of signal transduction pathways have been identified that regulate actin polymerization and contractility. GTP-binding proteins, protein kinases, phosphoinositide kinases, and protein phosphatases all play important roles in determining the location and extent of actin polymerization and contractility of actin/myosin filaments. These pathways allow cells to respond to extracellular signals to regulate movement, the tone of vascular smooth muscle cells, secretion, and phagocytosis. Some pathogens use signal transduction pathways that regulate actin polymerization to invade cells. The signal transduction pathways that regulate actin-dependent events are the focus of this review.

Atypical protein kinases Clambda and -zeta associate with the GTP-binding protein Cdc42 and mediate stress fiber loss

Both the Rho family of low-molecular-weight GTP-binding proteins and protein kinases C (PKCs) mediate responses to a variety of extracellular and intracellular signals. They share many downstream targets, including remodeling of the actin cytoskeleton, activation of p70(S6) kinase and c-jun N-terminal kinase (JNK), and regulation of transcription and cell proliferation. We therefore investigated whether Rho family GTP-binding proteins bind to PKCs. We found that Cdc42 associates with atypical PKCs (aPKCs) PKCzeta and -lambda in a GTP-dependent manner. The regulatory domain of the aPKCs mediates the interaction. Expression of activated Cdc42 results in the translocation of PKClambda from the nucleus into the cytosol, and Cdc42 and PKClambda colocalize at the plasma membrane and in the cytoplasm. Expression of activated Cdc42 leads to a loss of stress fibers, as does overexpression of either the wild type or an activated form of PKClambda. Kinase-dead PKClambda and -zeta constructs acted as dominant negatives and restored stress fibers in cells expressing the activated V12 Cdc42 mutant, indicating that Cdc42-dependent loss of stress fibers requires aPKCs. Kinase-dead PKClambda and -zeta and dominant-negative N17 Cdc42 also blocked Ras-induced loss of stress fibers, suggesting that this pathway may also be important for Ras-dependent cytoskeletal changes. N17 Rac did not block Ras-induced loss of stress fibers, nor did kinase-dead PKClambda block V12 Rac-stimulated loss of stress fibers. These results indicate that Cdc42 and Rac use different pathways to regulate stress fibers.

Type Ialpha phosphatidylinositol-4-phosphate 5-kinase mediates Rac-dependent actin assembly

Action polymerization is essential for a variety of cellular processes including movement, cell division and shape change. The induction of actin polymerization requires the generation of free actin filament barbed ends, which results from the severing or uncapping of pre-existing actin filaments [1] [2], or de novo nucleation, initiated by the Arp2/3 complex [3] [4] [5] [6] [7]. Although little is known about the signaling pathways that regulate actin assembly, small GTPases of the Rho family appear to be necessary [8] [9] [10] [11]. In thrombin-stimulated platelets, the Rho family GTPase Rac1 induces actin polymerization by stimulating the uncapping of actin filament barbed ends [2]. The mechanism by which Rac regulates uncapping is unclear, however. We previously demonstrated that Rac interacts with a type I phosphatidylinositol-4-phosphate 5-kinase (PIP 5-kinase) in a GTP-independent manner [12] [13]. Because PIP 5-kinases synthesize phosphatidylinositol-4,5-bisphosphate (PI(4,5)P(2)), a lipid that dissociates capping proteins from the barbed ends of actin filaments [14] [15] [16], they are good candidates for mediating the effects of Rac on actin assembly. Here, we have identified the Rac-associated PIP 5-kinase as the PIP 5-kinase isoforms alpha and beta. When added to permeabilized platelets, PIP 5-kinase alpha induced actin filament uncapping and assembly. In contrast, a kinase-inactive PIP 5-kinase alpha mutant failed to induce actin assembly and blocked assembly stimulated by thrombin or Rac. Furthermore, thrombin- or Rac-induced actin polymerization was inhibited by a point mutation in the carboxyl terminus of Rac that disrupts PIP 5-kinase binding. These results demonstrate that PIP 5-kinase alpha is a critical mediator of thrombin- and Rac-dependent actin assembly.

Lipid kinases are novel effectors of the GTPase Rac1

We have found that a complex consisting of a type I PIPK and a DGK associates with the GTPase Rac1. Binding of the lipid kinase complex is through the C-terminus of Rac. Complex formation is augmented in the presence of specific phospholipids. The complex also associates with Rho GDI, through Rac. Based on the role of PtdIns-4,5-P2 in regulating proteins that influence actin structures we propose that the Rac-associated lipid kinase complex functions to generate locally high concentrations of PtdIns-4,5-P2 in a Rac-dependent manner. There are many possible roles PtdIns-4,5-P2 might play. A likely role is binding to barbed-end actin capping proteins. This would release the capping protein, providing free barbed ends for actin polymerization. Uncapping would occur at the membrane so that additional actin polymerization would result in membrane protrusions and lamellapodia, in a Brownian ratchet model. It is also possible that PtdIns-4,5-P2 has other roles, such as promoting the release of G actin from profilin or promoting the cross-linking of actin or its anchorage to the plasma membrane. Studies are currently underway to determine the role of this lipid kinase complex in Rac signaling and actin regulation in vivo.

Lifetime exercise activity and breast cancer risk among post-menopausal women

Lifetime exercise activity has been linked to breast cancer risk among young women. However, no study has specifically evaluated whether lifetime exercise activity is related to the breast cancer risk of post-menopausal women. We conducted a population-based case-control study of post-menopausal white women (1123 newly diagnosed cases and 904 healthy controls) aged 55-64 who lived in Los Angeles County, California, USA to evaluate this relationship. Although neither exercise activity from menarche to age 40 years, nor exercise after age 40 separately predicted breast cancer risk, risk was lower among women who had exercised each week for at least 17.6 MET-hours (metabolic equivalent of energy expenditure multiplied by hours of activity) since menarche than among inactive women (odds ratio (OR) = 0.55; 95% confidence interval (CI) 0.37-0.83). Exercise activity was not protective for women who gained considerable (> 17%) weight during adulthood. However, among women with more stable weight, breast cancer risk was substantially reduced for those who consistently exercised at high levels throughout their lifetime (OR = 0.42; 95% CI 0.24-0.75), those who exercised more than 4 h per week for at least 12 years (OR = 0.59; 95% CI 0.40-0.88), and those who exercised vigorously (24.5 MET-hours per week) during the most recent 10 years (OR = 0.52; 95% CI 0.32-0.85). Strenuous exercise appears to reduce breast cancer risk among post-menopausal women who do not gain sizable amounts of weight during adulthood.

Prevalence of HIV-1 among recent arrestees in Los Angeles County, California: serial cross-sectional study, 1991-1995

Injection drug users (IDU), crack smokers, and commercial sex workers engage in illegal activities that place them at risk for HIV infection. The marginalized nature of these groups often limits use of customary sampling methods to assess HIV prevalence. We tested urine samples of recent arrestees to evaluate HIV prevalence of at-risk populations that are difficult to access using standard surveillance methods. We tested for HIV-1 antibodies in urine specimens of recent Los Angeles County (California, U.S.A.) arrestees as part of the Drug Use Forecasting (DUF) Program funded by the U. S. National Institute of Justice. Data are presented for 5 years of a serial cross-sectional study of arrestees. Results from 1991 through 1995 indicate a slight HIV prevalence increase among crack smokers (from 4% to 6%). Prevalence estimates were relatively stable for IDU (6%), male (3%) and female arrestees (3%), arrestees who share needles (9%), and commercial sex workers (6%). HIV status was independently associated with injection drug use, crack smoking, and ever having exchanged sex for money or drugs. Prevalence of HIV among arrestee subgroups may reflect prevalence in the community. However the benefit of using the DUF sample must be weighed against bias introduced from using nonrandom samples to estimate prevalence.

c-Jun is a JNK-independent coactivator of the PU.1 transcription factor

The ETS domain transcription factor PU.1 is necessary for the development of monocytes and regulates, in particular, the expression of the monocyte-specific macrophage colony-stimulating factor (M-CSF) receptor, which is critical for monocytic cell survival, proliferation, and differentiation. The bZIP transcription factor c-Jun, which is part of the AP-1 transcription factor complex, is also important for monocytic differentiation, but the monocyte-specific M-CSF receptor promoter has no AP-1 consensus binding sites. We asked the question of whether c-Jun could promote the induction of the M-CSF receptor by collaborating with PU.1. We demonstrate that c-Jun enhances the ability of PU.1 to transactivate the M-CSF receptor promoter as well as a minimal thymidine kinase promoter containing only PU.1 DNA binding sites. c-Jun does not directly bind to the M-CSF receptor promoter but associates via its basic domain with the ETS domain of PU.1. Consistent with our observation that AP-1 binding does not contribute to c-Jun coactivation is the observation that the activation of PU.1 by c-Jun is blocked by overexpression of c-Fos. Phosphorylation of c-Jun by c-Jun NH2-terminal kinase on Ser-63 and -73 does not alter the ability of c-Jun to enhance PU.1 transactivation. Activated Ras enhances the transcriptional activity of PU.1 by up-regulating c-Jun expression without changing the phosphorylation pattern of PU.1. The activation of PU.1 by Ras is blocked by a mutant c-Jun protein lacking the basic domain. The expression of this mutant form of c-Jun also completely blocks 12-O-tetradecanoylphorbol-13-acetate-induced M-CSF receptor promoter activity during monocytic differentiation. We propose therefore that c-Jun acts as a c-Jun NH2-terminal kinase-independent coactivator of PU.1, resulting in M-CSF receptor expression and development of the monocytic lineage.

Mentholated cigarette smoking and lung-cancer risk

PURPOSE

Menthol smoking may lead to a greater increase in lung-cancer risk than smoking of nonmentholated cigarettes. Mentholation of cigarettes adds additional carcinogenic components to cigarette smoke and increases retention times for cigarette smoke in the lungs. Only two epidemiologic studies have been conducted on menthol smoking and lung cancer, and their results are conflicting. Of note, African American males have much higher rates of lung cancer than Caucasian males despite smoking fewer cigarettes per day. Because the consumption of menthol cigarettes is much more frequent among African Americans, it is of interest to examine the possible association between menthol smoking and lung-cancer risk in this population.

METHODS

We examined the association between menthol cigarette smoking and lung-cancer risk among smokers by comparing 337 incident cases of lung cancer with 478 population controls enrolled in a case-control study of lung cancer. Information on smoking history and other known and potential risk factors for lung cancer, including dietary intake, was obtained by in-person interviews.

RESULTS

The adjusted odds ratios did not differ appreciably between smokers of mentholated cigarettes versus exclusive nonmentholated cigarette smokers in the overall study group of smokers. The odds ratio (OR) for 32 pack-years or more of mentholated vs. nonmentholated cigarettes was 0.90 (95% confidence interval (CI) = 0.38-2.12) in African Americans and 1.06 (95% CI = 0.47-2.36) in Caucasians, and did not differ for either ethnic group (p = 0.98).

CONCLUSIONS

Our results suggest that the lung-cancer risk from smoking mentholated cigarettes resembles the risk from smoking non-mentholated cigarettes. Our data do not support the hypothesis that the increased risk of lung cancer among African Americans is due to the increased prevalence of menthol smoking.

Risk factors for human T cell lymphotropic virus type I among injecting drug users in northeast Brazil: possibly greater efficiency of male to female transmission

It was observed in the city of Salvador, State of Bahia, the highest seroprevalence of human T cell lymphotropic virus type 1 (HTLV-I) infection in Brazil as demonstrated by national wide blood bank surveys. In this paper, we report results of an investigation of drug use and sexual behavior associated with HTLV-I infection among male and female injecting drug users (IDUs) in Salvador. A cross sectional study was conducted in the Historical District of Salvador from 1994-1996 (Projeto Brasil-Salvador) and 216 asymptomatic IDUs were selected using the snowball contact technique. Blood samples were collected for serological assays. Sera were screened for human immunodeficiency virus (HIV-1/2) and HTLV-I/II antibodies by ELISA and confirmed by Western blot. The overall prevalence of HTLV-I/II was 35.2% (76/216). The seroprevalence of HTLV-I, HTLV-II and HIV-I was for males 22%, 11.3% and 44.1% and for females 46.2%, 10.3% and 74.4% respectively. HTLV-I was identified in 72.4% of HTLV positive IDUs. Variables which were significantly associated with HTLV-I infection among males included needle sharing practices, duration of injecting drug use, HIV-I seropositivity and syphilis. Among women, duration of injecting drug use and syphilis were strongly associated with HTLV-I infection. Multivariate analysis did not change the direction of these associations. Sexual intercourse might play a more important role in HTLV-I infection among women than in men.

Enhancement of phosphoinositide 3-kinase (PI 3-kinase) activity by membrane curvature and inositol-phospholipid-binding peptides

The phosphorylation of phosphatidylinositol (PtdIns) on the 3' position of the inositol ring by phosphoinositide 3-kinase (PI 3-kinase) is shown to depend strongly on the curvature of liposomes containing a mixture of phosphatidylcholine (PtdCho) and PtdIns. Vesicles with an average diameter of 50 nm are phosphorylated 100 times faster than chemically identical vesicles with an average diameter greater than 300 nm. The low reactivity of large vesicles is not due to the difference in vesicle number for large and small vesicles at constant total lipid, nor to occlusion of lipid surfaces in multilammelar structures, and can be reversed by addition of low (< 1:100) molar ratios of either the PtdIns transfer protein sec14p or a ten-residue peptide derived from the inositol-phospholipid-binding site of gelsolin. Similar measurements using PI 4-kinase showed a weak dependence on vesicle size. The strong dependence of PI 3-kinase function on membrane curvature suggests possible localization of PI 3-kinase activity at sites where clustering of receptors, for example, may locally deform the membrane, and suggests that once PI 3-kinase is localized and activated at surface sites, the reaction may become self-accelerating.

Type I phosphatidylinositol-4-phosphate 5-kinases synthesize the novel lipids phosphatidylinositol 3,5-bisphosphate and phosphatidylinositol 5-phosphate

Inositol phospholipids regulate a variety of cellular processes including proliferation, survival, vesicular trafficking, and cytoskeletal organization. Recently, two novel phosphoinositides, phosphatidylinositol-3,5-bisphosphate (PtdIns-3,5-P2) and phosphatidylinositol- 5-phosphate (PtdIns-5-P), have been shown to exist in cells. PtdIns-3,5-P2, which is regulated by osmotic stress, appears to be synthesized by phosphorylation of PtdIns-3-P at the D-5 position. No evidence yet exists for how PtdIns-5-P is produced in cells. Understanding the regulation of synthesis of these molecules will be important for identifying their function in cellular signaling. To determine the pathway by which PtdIns-3,5-P2 and Ptd-Ins-5-P might be synthesized, we tested the ability of the recently cloned type I PtdIns-4-P 5-kinases (PIP5Ks) alpha and beta to phosphorylate PtdIns-3-P and PtdIns at the D-5 position of the inositol ring. We found that the type I PIP5Ks phosphorylate PtdIns-3-P to form PtdIns-3,5-P2. The identity of the PtdIns-3,5-P2 product was determined by anion exchange high performance liquid chromatography analysis and periodate treatment. PtdIns-3,4-P2 and PtdIns-3,4,5-P3 were also produced from PtdIns-3-P phosphorylation by both isoforms. When expressed in mammalian cells, PIP5K Ialpha and PIP5K Ibeta differed in their ability to synthesize PtdIns-3,5-P2 relative to PtdIns-3,4-P2. We also found that the type I PIP5Ks phosphorylate PtdIns to produce PtdIns-5-P and phosphorylate PtdIns-3,4-P2 to produce PtdIns-3,4,5-P3. Our findings suggest that type I PIP5Ks synthesize the novel phospholipids PtdIns-3,5-P2 and PtdIns-5-P. The ability of PIP5Ks to produce multiple signaling molecules indicates that they may participate in a variety of cellular processes.

Alcoholic beverage consumption and lung cancer risk among residents of Los Angeles County

Although studies generally support a positive association between alcohol consumption and lung-cancer risk, the relationship between specific alcoholic beverages and lung-cancer risk has been inconsistent. We examined recent and past alcoholic beverage intake among 261 incident cases and 615 population controls enrolled in a lung-cancer case-control study of African Americans and Caucasians in Los Angeles County between 1991 and 1994. An in-person interview elicited information about past alcohol intake from ages 30 to 40 y, smoking, other lung-cancer risk factors, as well as recent intake of alcohol, and recent dietary intake. An association was observed between recent hard-liquor consumption and lung-cancer risk. The odds ratio (OR) for 1 or more drinks (1.5 oz or 0.051 mL) per day of hard liquor compared with infrequent liquor drinking (0-3 drinks per month), adjusted for smoking, the matching factors, saturated fat and other alcoholic beverages was 1.87 [95% confidence interval (CI) = 1.02-3.42]. No appreciable association was observed for total alcohol, whereas small inverse associations were observed for beer and wine, although confidence intervals were wide. An elevated lung-cancer risk was also observed for past liquor consumption (between ages 30 and 40 y). The adjusted OR for 1 or more drinks per day of liquor compared with infrequent drinkers was 1.83 (95% CI = 1. 06-3.15). Confounding of the association between alcohol and lung cancer by smoking was apparent. Although we devoted considerable efforts to adjusting for smoking in our analyses, residual confounding is still possible because smoking and alcohol are closely associated. In addition, case-control studies including this study should be viewed with caution because of possible selection bias. An increased risk of lung cancer might occur with moderate drinking of hard liquor but confirmation is required in larger studies.

Characterization of a Rac1- and RhoGDI-associated lipid kinase signaling complex

Rho family GTPases regulate a number of cellular processes, including actin cytoskeletal organization, cellular proliferation, and NADPH oxidase activation. The mechanisms by which these G proteins mediate their effects are unclear, although a number of downstream targets have been identified. The interaction of most of these target proteins with Rho GTPases is GTP dependent and requires the effector domain. The activation of the NADPH oxidase also depends on the C terminus of Rac, but no effector molecules that bind to this region have yet been identified. We previously showed that Rac interacts with a type I phosphatidylinositol-4-phosphate (PtdInsP) 5-kinase, independent of GTP. Here we report the identification of a diacylglycerol kinase (DGK) which also associates with both GTP- and GDP-bound Rac1. In vitro binding analysis using chimeric proteins, peptides, and a truncation mutant demonstrated that the C terminus of Rac is necessary and sufficient for binding to both lipid kinases. The Rac-associated PtdInsP 5-kinase and DGK copurify by liquid chromatography, suggesting that they bind as a complex to Rac. RhoGDI also associates with this lipid kinase complex both in vivo and in vitro, primarily via its interaction with Rac. The interaction between Rac and the lipid kinases was enhanced by specific phospholipids, indicating a possible mechanism of regulation in vivo. Given that the products of the PtdInsP 5-kinase and the DGK have been implicated in several Rac-regulated processes, and they bind to the Rac C terminus, these lipid kinases may play important roles in Rac activation of the NADPH oxidase, actin polymerization, and other signaling pathways.

Signal transduction pathways involving the small G proteins rac and Cdc42 and phosphoinositide kinases

We found that rac specifically binds to a type I PtdIns-4-P 5-kinase and that both rac and Cdc42 in the activated forms associate with PI 3-kinase. The association of PI 3-kinase with rac was stimulated by PDGF in vivo. Rac is constitutively associated with a PtdIns-4-P 5-kinase and stimulates PtdIns-4,5-P2 production in permeabilized platelets. These data suggest a model in which the initial step in the activation of rac is release from rho GDI (Fig. 7). Rac in the GDP bound form can associate with the PtdIns-4-P 5-kinase and also interact with an exchange factor. GTP bound rac may then localize to sites of actin reorganization, bringing the PtdIns-4-P 5-kinase with it. Locally synthesized PtdIns-4,5-P2 binds to actin capping proteins, leading to their release and the production of actin free ends. Actin polymerization can then occur from the free ends. Many other factors must be involved to regulate the type and extent of actin polymerization that is necessary in such complex processes as cell movement and membrane ruffling. The rac-associated PtdIns-4-P 5-kinase and its product PtdIns-4,5-P2 may act at a crucial regulatory point that permits polymerization to begin.

Is cryosurgical ablation appropriate for treating hepatocellular cancer?

OBJECTIVE

To examine the feasibility and efficacy of cryosurgical ablation as treatment for patients with cirrhosis with unresectable hepatocellular carcinoma.

DESIGN

Retrospective case series.

SETTING

A tertiary public hospital and a cancer center.

PATIENTS

Twelve patients with cirrhosis with hepatocellular carcinoma (stage II, 2; stage III, 1; stage IVA, 7; stage IVB, 2).

INTERVENTIONS

Cryosurgical ablation of all identifiable tumors. Nine patients treated with curative intent were included in the survival analysis, and 3 were treated for palliation. Five patients were treated with preoperative intra-arterial chemoembolization.

MAIN OUTCOME MEASURES

Perioperative complications and the effects of tumor stage and chemoembolization were examined. Patient survival and disease-free interval were calculated by life-table analysis.

RESULTS

No perioperative deaths occurred and 1 patient had 2 postoperative complications: pneumonia and biloma. The mean survival has been 19 months after cryosurgical ablation and 29 months after diagnosis. Three of the 9 patients treated with curative intent died with recurrence at a mean of 17 months after cryosurgical ablation. Four patients are alive with recurrence at a mean of 19 months after cryosurgical ablation and 38 months after diagnosis. Two patients with stage II disease have no evidence of recurrence 10 and 32 months after cryosurgical ablation.

CONCLUSIONS

Cryosurgical ablation is feasible and safe for treatment of hepatocellular carcinoma in patients with cirrhosis. The technique is primarily palliative but may provide a possibility of cure in patients with lower-stage disease.

A novel link between integrins, transmembrane-4 superfamily proteins (CD63 and CD81), and phosphatidylinositol 4-kinase

Enzymatic and immunochemical assays show a phosphatidylinositol 4-kinase in novel and specific complexes with proteins (CD63 and CD81) of the transmembrane 4 superfamily (TM4SF) and an integrin (alpha3beta1). The size (55 kDa) and other properties of the phosphatidylinositol 4-kinase (PI 4-K) (stimulated by nonionic detergent, inhibited by adenosine, inhibited by monoclonal antibody 4CG5) are consistent with PI 4-K type II. Not only was PI 4-K associated with alpha3beta1-CD63 complexes in alpha3-transfected K562 cells, but also it could be co-purified from CD63 in untransfected K562 cells lacking alpha3beta1. Thus, TM4SF proteins may link PI 4-K activity to the alpha3beta1 integrin. The alpha5beta1 integrin, which does not associate with TM4SF proteins, was not associated with PI 4-K. Notably, alpha3beta1-CD63-CD81-PI 4-K complexes are located in focal complexes at the cell periphery rather than in focal adhesions. The novel linkage between integrins, transmembrane 4 proteins, and phosphoinositide signaling at the cell periphery may play a key role in cell motility and provides a signaling pathway distinct from conventional integrin signaling through focal adhesion kinase.

Environmental assessment of the alkanolamines

This review provides a summary of current information available on the environmental fate and aquatic toxicology of the alkanolamines. Because these materials are widely used, there is a need to understand their fate and effects in the environment. This assessment was confined to information regarding selected physical properties of the alkanolamines as well as their potential for degradation in the atmosphere, soil, surface water, and groundwater. In addition, their relevant aquatic toxicological information and bioconcentration potential were evaluated. In general, the alkanolamines have high water solubilities and low to moderate vapor pressures. Some are solids whereas others are liquids at room temperature. Aqueous solutions of the alkanolamines are basic, with the pKas decreasing with increased alkyl substitution. Predictions of the environmental distribution of these compounds, based on a unit world model of Mackay and Paterson, suggested that alkanolamines would partition primarily into the aqueous compartment at equilibrium, with the remainder distributed to the atmosphere. Only a very small fraction of these materials is expected to sorb to soil or sediments. However, adsorption mechanisms other than partitioning into the soil organic layer were not considered in this model. Since polar compounds may sorb to soil by alternate mechanisms, this model may underestimate the true adsorption potential and subsequent environmental distribution of the alkanolamines. Future work with these compounds should focus on other types of adsorption mechanisms that could impact the environmental distribution of the alkanolamines. Although only small amount of the alkanolamines are expected to partition to the atmosphere, they are expected to be removed by reactions with photochemically generated hydroxyl radicals. They may also be removed from the atmosphere by precipitation, due to their high water solubility. Because of the relatively low levels expected to be present in the atmosphere and the relatively short half-lives, the alkanolamines are not expected to adversely impact air quality. Alkanolamines have also been shown to be highly susceptible to biodegradation and are not expected to persist in the environment. Results from numerous studies have shown that these materials undergo rapid biodegradation in soil, surface waters, and wastewater treatment plants. Degradation rates for these compounds may vary, with half-lives routinely in the range of 1 d to 2 wk, depending on the length of acclimation period and other environmental factors. The relatively low bioconcentration factor (BCF) values reported for the alkanolamines indicate that they would not be expected to bioconcentrate in aquatic organisms. Available data on the toxicity of the alkanolamines to aquatic organisms suggest low toxicity to the majority of the species studied. Based on the facts that alkanolamines exhibit low aquatic toxicity, are shown to biodegrade in a wide range of environments, and exhibit no tendency to bioaccumulate, the routine manufacturing, use, and disposal of these materials are not expected to adversely impact the environment. With increased emphasis by consumers and regulatory agencies for industry to develop products that are "environmentally friendly," these properties of the alkanolamines make them an attractive choice for a wide range of applications.

Structural organization and alternative splicing of the murine phosphoinositide 3-kinase p85 alpha gene

Phosphoinositide 3-kinase is a lipid and protein kinase composed of a 110-kDa catalytic subunit and an 85-kDa (p85) or 55-kDa (p55) regulatory subunit. In mammals, at least two genes encode catalytic subunits, and at least three genes encode regulatory subunits. Here we report the cloning and structural analysis of the mouse p85 alpha gene. The translated portion of mouse p85 alpha is encoded by 15 exons that span at least 40 kb. We have cloned an alternatively spliced form of p85 alpha from both mouse and rat cDNA libraries. This splice variant encodes a unique 5'-untranslated region, start codon, and 6-amino-acid aminoterminus followed by the carboxyterminal 418 amino acids of p85 alpha. A corresponding exon is present within the p85 alpha genomic locus. In vitro transcription and translation of the splice variant cDNA generate a protein of approximately 45 kDa that is reactive with an anti-p85 alpha antiserum. Northern blot analysis of mouse tissues reveals differential expression of full-length and alternatively spliced p85 alpha, with the splice variant most abundant in the liver.

Assessment of resectability of pancreatic head and periampullary tumors by color flow Doppler sonography

OBJECTIVE

To examine the sensitivity of color flow Doppler ultrasonography in assessing resectability of pancreatic head and periampullary tumors.

DESIGN

Validation cohort study.

SETTING

Tertiary care public hospital.

PATIENTS

Thirty-seven patients with pancreatic head or periampullary cancer were studied by color flow Doppler examination of the relevant blood vessels.

MAIN OUTCOME MEASURE

A pancreatic Doppler score (PDS) was defined as the closest circumferential contact of the tumor to the superior mesenteric vein, superior mesenteric artery, or portal vein. A PDS of 1 indicated no contact (n = 9); PDS 2, less than 50% contact (n = 10); PDS 3, 50% to 99% contact (n = 7); and PDS 4, encasement (n = 11). The PDS was compared with operative and histologic resection margins.

RESULTS

The lack of vascular invasion was confirmed operatively in 7 of 7 patients with a PDS of 1, and 6 patients who underwent resection had clear histologic margins. Nine (90%) of 10 patients with a PDS of 2 were confirmed to have no vascular invasion, and 3 (43%) of 7 patients who underwent resection had clear margins. Five (83%) of 6 patients with a PDS of 3 had correct operative findings, and both patients who underwent resection had positive margins. Operative confirmation of encasement was found in all 7 patients with a PDS of 4 who had operative exploration, and none underwent resection.

CONCLUSIONS

Color flow Doppler sonography and PDS predicted resectability and the histologic margin status (positive predictive value, 97%). Patients with a PDS of 1 are predicted to have clear histologic margins after resection. Patients with a PDS of 4 have unresectable tumors, and nonoperative palliation should be considered. Patients with a PDS of 2 or 3 have a high likelihood of positive histologic margins after resection and may be candidates for neoadjuvant chemotherapy.

Direct interaction of the Wiskott-Aldrich syndrome protein with the GTPase Cdc42

Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency disorder with the most severe pathology in the T lymphocytes and platelets. The disease arises from mutations in the gene encoding the WAS protein. T lymphocytes of affected males with WAS exhibit a severe disturbance of the actin cytoskeleton, suggesting that the WAS protein could regulate its organization. We show here that WAS protein interacts with a member of the Rho family of GTPases, Cdc42. This interaction, which is guanosine 5'-triphosphate (GTP)-dependent, was detected in cell lysates, in transient transfections and with purified recombinant proteins. A weaker interaction was also detected with Rac1 using WAS protein from cell lysates. It was also found that different mutant WAS proteins from three affected males retained their ability to interact with Cdc42 and that the level of expression of the WAS protein in these mutants was only 2-5% of normal. Taken together these data suggest that the WAS protein might function as a signal transduction adaptor downstream of Cdc42, and in affected males, the cytoskeletal abnormalities may result from a defect in Cdc42 signaling.

Lung cancer risk in relation to the CYP2E1 Rsa I genetic polymorphism among African-Americans and Caucasians in Los Angeles County

Genetic polymorphisms in the activation or detoxication of carcinogens, such as those in tobacco smoke, may produce differences in individual susceptibility to lung cancer. The cytochrome P450 CYP2E1 is an enzyme involved in the metabolism of nitrosamines in tobacco smoke. A polymorphism of CYP2E1 detectable by the restriction enzyme Rsa I may be functionally important because it is located in a putative binding site for the transcription factor HNF-1 and has been associated with higher levels of CYP2E1 transcription. It is conceivable that this CYP2E1 Rsa I polymorphism might contribute to differences in susceptibility to lung cancer. We conducted a case-control study of patients with incident lung cancer and population controls in Los Angeles County to examine the association between the CYP2E1 Rsa I polymorphism and lung cancer risk among African-Americans and Caucasians. Samples of white blood cell DNA sufficient for determination of the CYP2E1 Rsa I genotype by a polymerase chain reaction-based assay were obtained from 341 cases and 706 controls with data on lifetime smoking history. No subjects were homozygous for the CYP2E1 Rsa I rare c2 allele. The rare c2 allele was not associated with an increased risk of lung cancer (adjusted odds ratio, OR 0.72; 95% confidence interval, CI = 0.35-1.46). Among the population controls the percentage of subjects carrying the rare c2 allele was lower (p = 0.002) among African-Americans (2%) compared with Caucasians (8%). However, the association between the CYP2E1 Rsa I genotype and lung cancer risk did not differ between ethnic groups. There was no important association between the CYP2E1 Rsa I genotype and lung cancer risk in analyses stratified by cell-type, smoking history, gender, occupational asbestos exposure, and dietary intake of antioxidants vitamin C, vitamin E or beta carotene. Due to the low frequency of the c2 allele in these populations, larger studies would be necessary to rule out a modest association between the CYP2E1 Rsa I polymorphism and lung cancer risk.

Phosphoinositide kinases

Recently, a number of cDNA clones with homology to the catalytic subunit of phosphoinositide 3-kinase have been identified, and the sequence of the first cDNA clone encoding a phosphatidylinositol 4-phosphate 5-kinase has been published. Use of both dominant-negative mutants of phosphoinositide 3-kinase and the inhibitors wortmannin and LY294002 has identified a number of processes in which phosphoinositide 3-kinase participates, including cell motility, the Ras pathway, vesicle trafficking and secretion, and apoptosis. Several possible biochemical targets of phosphoinositides have been found.

Lung cancer risk in African-Americans in relation to a race-specific CYP1A1 polymorphism

The possible association between lung cancer and a polymorphism of the CYP1A1 gene specific to African-Americans was examined using peripheral blood DNA from 144 incident cases of lung cancer and 230 population controls with detailed data on smoking and other risk factors for the disease. The CYP1A1 variant allele was present in 15.2% of controls and 16.7% of cases. The smoking-adjusted odds ratio for the presence of the variant allele in relation to lung cancer risk overall was 1.3 (95% confidence interval, 0.7-2.4). According to histological type, the strongest association was observed for squamous cell carcinoma (odds ratio, 2.1), but this result was compatible with chance (95% confidence interval, 0.8-5.9). Adenocarcinoma was not materially associated with the presence of the variant allele (odds ratio, 1.3; 95% confidence interval, 0.5-3.2). No important associations were observed upon stratification by several risk factors for lung cancer, including smoking history, occupational exposures to asbestos and motor vehicle exhaust, or low intake of the micronutrient antioxidants beta-carotene, vitamin E, or vitamin C. These results do not confirm an earlier report that this CYP1A1 polymorphism may be an important risk factor for adenocarcinoma of the lung in African-Americans.

Phosphoinositide 3-kinase binds constitutively to alpha/beta-tubulin and binds to gamma-tubulin in response to insulin

Recently we reported the localization of phosphoinositide 3-kinase (PI 3-kinase) by immunofluorescence to microtubule bundles and the centrosome (Kapeller, R., Chakrabarti, R., Cantley, L., Fay, F., and Corvera, S. (1993) Mol. Cell. Biol. 13, 6052-6063). In complementary experiments we used the recombinant p85 subunit of PI 3-kinase to identify proteins that associate with phosphoinositide 3-kinase and found that phosphoinositide 3-kinase associates with alpha/beta-tubulin. The association occurs in vivo but was not significantly affected by growth factor stimulation. We localized the region of p85 that interacts with alpha/beta-tubulin to the inter-SH2 domain. These results support the immunofluorescence data and show that p85 directly associates with alpha/beta-tubulin. We then determined whether phosphoinositide 3-kinase associates with gamma-tubulin. We found a dramatic growth factor-dependent association of phosphoinositide 3-kinase with gamma-tubulin. Phosphoinositide 3-kinase associates with gamma-tubulin in response to insulin and, to a lesser extent, in response to platelet-derived growth factor. Neither epidermal growth factor nor nerve growth factor treatment of cells results in association of phosphoinositide 3-kinase and gamma-tubulin. Phosphoinositide 3-kinase is also immunoprecipitated with antibodies to pericentrin in response to insulin, indicating that phosphoinositide 3-kinase is recruited to the centrosome. Neither phosphoinositide 3-kinase activity, nor intact microtubules are necessary for the association. Treatment of cells with 0.5 M NaCl dissociates gamma-tubulin from the centrosome and disrupts the association of phosphoinositide 3-kinase with pericentrin, but not gamma-tubulin. Recombinant p85 binds to gamma-tubulin from both insulin stimulated and quiescent cells. These results suggest that the association of phosphoinositide 3-kinase with gamma-tubulin is direct. These data suggest that phosphoinositide 3-kinase may be involved in regulating microtubule responses to insulin and platelet-derived growth factor.

Thrombin receptor ligation and activated Rac uncap actin filament barbed ends through phosphoinositide synthesis in permeabilized human platelets

Cells respond to diverse external stimuli by polymerizing cytoplasmic actin, and recent evidence indicates that GTPases can specify where this polymerization takes place. Actin assembly in stimulated blood platelets occurs where sequestered monomers add onto the fast-growing (barbed) ends of actin filaments (F-actin), which are capped in the resting cells. We report that D3 and D4 polyphosphoinositides, Pl(4)P, Pl(4,5)P2, Pl(3,4)P2, and Pl(3,4,5)P3, uncap F-actin in resting permeabilized platelets. The thrombin receptor-activating peptide (TRAP), GTP, and GTP gamma S, but not GDP beta S, also uncap F-actin in permeabilized platelets. GDP beta S inhibits TRAP-induced F-actin uncapping, and Pl(4,5)P2 overcomes this inhibition. Constitutively active mutant Rac, but not Rho, activates uncapping of F-actin. Pl(4,5)P2-binding peptides derived from gelsolin inhibit F-actin uncapping by TRAP, Rac, and GTP gamma S. TRAP and Rac induce rapid Pl(4,5)P2 synthesis in permeabilized platelets. The findings establish a signaling pathway for actin assembly involving Rac in which the final message is phosphoinositide-mediated F-actin uncapping.

Polymorphism of glutathione S-transferase M1 and lung cancer risk among African-Americans and Caucasians in Los Angeles County, California

BACKGROUND

Glutathione S-transferase M1 (GSTM1) is active in the detoxication of a number of carcinogens, including polyaromatic hydrocarbons, such as those present in cigarette smoke. In about 30%-55% of individuals, depending on the ethnic group, there is a virtual absence of GSTM1 enzyme activity due to deletion of both copies of the GSTM1 gene (GSTM1 null genotype). This genetic polymorphism of the GSTM1 gene locus has been proposed as a risk factor for lung cancer. However, results across studies are inconsistent.

PURPOSE

We conducted a case-control study of patients with incident lung cancer and population control subjects to examine the association between homozygous deletion of the GSTM1 gene and lung cancer risk among African-Americans and Caucasians.

METHODS

At 35 hospitals in Los Angeles County, California, we identified patients with a first diagnosis of lung cancer between September 1, 1990, and January 6, 1994. Of the 859 potentially eligible case patients, 207 had died by the time their physicians had received our request for permission to contact them. We enrolled 356 eligible case patients (167 African-Americans and 189 Caucasians) and 731 eligible control subjects (258 African-Americans and 473 Caucasians, all residents of Los Angeles County). Samples of white blood cell DNA sufficient for determination of the GSTM1 genotype by a polymerase chain reaction-based assay were obtained from 342 case patients and 716 control subjects. The odds ratios (ORs) and 95% confidence intervals (CIs) for lung cancer associated with homozygous deletion of the GSTM1 gene, in total and after stratification by a number of relevant characteristics, were estimated by logistic regression analysis.

RESULTS

For patients with all lung cancers combined, the GSTM1 null genotype was associated with an OR of 1.29 (95% CI = 0.94-1.77). The OR was similar among African-Americans (OR = 1.20; 95% CI = 0.72-2.00) and Caucasians (OR = 1.37; 95% CI = 0.91-2.06). The association was strongest for squamous cell carcinoma (OR = 1.57; 95% CI = 0.93-2.63). We observed an OR of 1.77 (95% CI = 1.11-2.82) for the GSTM1 null genotype in relation to lung cancer risk among smokers of less than 40 pack-years, but no association among heavier smokers (OR = 0.90; 95% CI = 0.56-1.44).

CONCLUSIONS

Our data do not support a substantial association between homozygous deletion of the GSTM1 gene and the risk of lung cancer overall in this population. However, our data do suggest an elevated risk for lighter smokers with this genotype.

IMPLICATIONS

Because the power of our analyses within strata of lifetime smoking history was limited, larger studies will be needed to confirm these findings.

Rho family GTPases bind to phosphoinositide kinases

Rho family GTPases appear to play an important role in the regulation of the actin cytoskeleton, but the mechanism of regulation is unknown. Since phosphoinositide 3-kinase and phosphatidylinositol 4,5-bisphosphate have also been implicated in actin reorganization, we investigated the possibility that Rho family members interact with phosphoinositide kinases. We found that both GTP- and GDP-bound Rac1 associate with phosphatidylinositol-4-phosphate 5-kinase in vitro and in vivo. Phosphoinositide 3-kinase also bound to Rac1 and Cdc42Hs, and these interactions were GTP-dependent. Stimulation of Swiss 3T3 cells with platelet-derived growth factor induced the association of PI 3-kinase with Rac in immunoprecipitates. PI 3-kinase activity was also detected in Cdc42 immunoprecipitates from COS7 cells. These results suggest that phosphoinositide kinases are involved in Rho family signal transduction pathways and raise the possibility that the effects of Rho family members on the actin cytoskeleton are mediated in part by phosphoinositide kinases.

The phosphatidylinositol 3-kinase serine kinase phosphorylates IRS-1. Stimulation by insulin and inhibition by Wortmannin

Phosphatidylinositol 3-kinase (PI 3-kinase) is a heterodimer composed of an 85-kDa subunit that binds tyrosyl-phosphorylated proteins via its SH2 domains and a 110-kDa catalytic subunit. Expression and mutagenesis experiments have shown that the 110-kDa subunit is a dual specificity kinase that possesses both lipid and serine kinase activities. Except for the 85- and 110-kDa subunits of PI 3-kinase, however, no endogenous substrates for the serine kinase have been identified. The results of the present study show that another target of this kinase is the insulin receptor substrate, IRS-1. Serine phosphorylation of IRS-1 as well as the 85-kDa subunit of PI 3-kinase was demonstrated in immunoprecipitates of PI 3-kinase and IRS-1 isolated from rat adipocytes incubated with insulin. In adipocytes incubated in the absence of insulin, only the serine phosphorylation of p85 was observed in immunoprecipitates of PI 3-kinase. Both the serine and lipid kinase activities of PI 3-kinase were abolished by the fungal metabolite Wortmannin. Wortmannin also partially inhibited the ability of insulin to stimulate glucose transport and inhibit lipolysis in fat cells. These data raise the possibility that the serine kinase activity of PI 3-kinase is involved in insulin signaling. They also suggest that inhibition of the lipid or serine kinase activities of PI 3-kinase could explain the effect of Wortmannin to diminish insulin action.

Activation of PI 3-kinase in 3T3-L1 adipocytes by association with insulin receptor substrate-1

Insulin treatment of adipocytes causes the rapid phosphorylation of the insulin receptor substrate-1 (IRS-1) on tyrosine. The phosphotyrosine [Tyr(P)] form of IRS-1 then complexes with the enzyme phosphatidylinositol (PI) 3-kinase. In this study, we have investigated the effect of this association on PI 3-kinase activity in 3T3-L1 adipocytes. Insulin stimulated cytosolic PI 3-kinase activity about sevenfold. This stimulation was maximal after 1 min of exposure of cells to insulin, persisted for at least 1 h, and occurred over the range of insulin concentrations that saturate its receptor. By means of immunoprecipitation of IRS-1, it was shown that virtually all of the enhanced activity was due to PI 3-kinase complexed with IRS-1. Moreover, the purified Tyr(P) form of IRS-1, either isolated from 3T3-L1 adipocytes or obtained by phosphorylation of the recombinant protein with the insulin receptor, markedly stimulated the activity of purified rat liver PI 3-kinase. These results show that the association of Tyr(P) IRS-1 with PI 3-kinase activates the enzyme and thereby can explain the elevation of PI 3,4-bisphosphate and PI 3,4,5-trisphosphate in vivo observed upon treatment of adipocytes with insulin.

Survival in amyotrophic lateral sclerosis. The role of psychological factors

OBJECTIVE

Examining the relationship between psychological status and survival in amyotrophic lateral sclerosis. Our hypothesis is that psychological distress is associated with greater mortality and shorter survival time than psychological well-being.

DESIGN

Cross-sectional, longitudinal. The baseline evaluations used were disease severity and 10 psychometric tests. A psychological status score was derived from these tests. Survival status was monitored for 3.5 years. Interviewers were blinded to other interviews and data analysis.

SETTING

Patient's residence.

PATIENTS

The criteria for eligibility were diagnosis of amyotrophic lateral sclerosis by a neurologist, dementia or alcoholism absent, communication in English, and any severity or length of disease. It was a volunteer sample consisting of 144 patients from amyotrophic lateral sclerosis clinics or community-based amyotrophic lateral sclerosis support groups. In this sample 66% were men, 94% were white, mean age at diagnosis was 55 years, 79% were married, 60% had some college education, and 61% died during the study.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

END POINTS

mortality during study, survival time from intake to last follow-up.

RESULTS

Comparison between high and low psychological score groups: 32% of high and 82% of low died; survival curves were significantly different. Controlling for confounding factors (length of illness, disease severity, age), patients with psychological distress had a greater risk of mortality (relative risk, 6.76; 95% confidence limits, 1.69 to 27.12) and greater likelihood of dying in any given time period (relative risk, 2.24; 95% confidence limits, 1.08 to 4.64) than those with psychological well-being.

CONCLUSION

Adjusting for confounding factors, psychological status is strongly related to outcome in amyotrophic lateral sclerosis. Further studies on psychological status should be done to confirm its prognostic value.

Rapid smoking of menthol and nonmenthol cigarettes by black and white smokers

White subjects took significantly more puffs of cigarette smoke before stopping than did black subjects in a modified, controlled-dose rapid smoking procedure. Paradoxically, however, no racial differences were detected for changes in carbon monoxide levels, or changes in cardiovascular variables (systolic and diastolic blood pressure, and heart rate). Due to the cooling and topical anesthetic properties of menthol, it was hypothesized that menthol and regular cigarette smokers would take more puffs from menthol cigarettes than from regular cigarettes before stopping in the controlled-dose rapid smoking procedure. However, no difference was observed for the number of puffs taken from regular as opposed to menthol cigarettes (cigarette type condition) and no differences were found for Cigarette Preference (regular smokers vs. menthol smokers).

Biodegradation of aircraft deicing fluids in soil at low temperatures

The effects of substrate concentration and temperature on the biodegradation of five different aircraft deicing fluids was examined in soil samples obtained from an area adjacent to an airport runway. The principle organic constituents, which included ethylene, propylene, and diethylene glycols, were shown to be mineralized to carbon dioxide in soil microcosms incubated at temperatures ranging from -2 to 25 degrees C. No lag period was observed, and biological transformation of the test chemicals began immediately after addition to the soil. Glycol biodegradation was observed in soil at concentrations ranging from 392 to 5278 mg/kg, suggesting that high levels of the deicing fluids are unlikely to be inhibitory to soil microorganisms. All three glycols were readily degraded in soil at 8 and 25 degrees C, regardless of whether the compounds were present singly or as a component of a mixture. In addition, the biodegradation rates for the three compounds were very similar. Average rates were in the range of 19.7 to 27.0 mg/kg soil per day at 8 degrees C and 66.3 to 93.3 mg/kg soil per day for soil samples incubated at 25 degrees C. The soil biodegradation rates were reduced in soils at -2 degrees C to between 2.3 and 4.5 mg/kg per day. Based on these results, biodegradation is expected to play a major role in removing residual levels of glycols from soils adjacent to airport taxiways and runways.