Therapeutic failure in American cutaneous leishmaniasis is associated with gelatinase activity and cytokine expression.

Cutaneous lesions caused by Leishmania braziliensis infection occasionally heal spontaneously, but with antimonials therapy heal rapidly in approximately 3 weeks. However, about 15% of the cases require several courses of therapy. Matrix metalloproteinase-2 (MMP-2) and MMP-9 are gelatinases that have been implicated in other chronic cutaneous diseases and skin re-epithelialization. These enzymes are controlled by their natural inhibitors [tissue inhibitors of metalloproteinase (TIMPs)] and by some cytokines. Uncontrolled gelatinase activity may result in intense tissue degradation and, consequently, poorly healing wounds. The present study correlates gelatinase activity to therapeutic failure of cutaneous leishmaniasis (CL) lesions. Our results demonstrate an association between gelatinase activity and increased numbers of cells making interferon (IFN)-γ, interleukin (IL)-10 and transforming growth factor (TGF)-ß in lesions from poor responders. Conversely, high levels of MMP-2 mRNA and enhanced MMP-2 : TIMP-2 ratios were associated with a satisfactory response to antimonials treatment. Additionally, high gelatinolytic activity was found in the wound beds, necrotic areas in the dermis and within some granulomatous infiltrates. These results indicate the importance of gelatinase activity in the skin lesions caused by CL. Thus, we hypothesize that the immune response profile may be responsible for the gelatinase activity pattern and may ultimately influence the persistence or cure of CL lesions.

Plasma and lung macrophage responsiveness to carotenoid supplementation and ozone exposure in humans.

OBJECTIVE: To examine the effect of ozone exposure and vegetable juice supplementation on plasma and lung macrophage concentrations of carotenoids. DESIGN: A randomized trial. SETTING: Subjects were exposed to ambient air prior to antioxidant supplementation and to ozone after antioxidant supplementation or placebo. Exposures occurred while exercising intermittently in a controlled metabolic chamber at the Human Studies Division, US EPA. SUBJECTS: In all, 23 healthy subjects between ages of 18 and 35 y. INTERVENTIONS: Subjects consumed a low fruit and vegetable diet for 3 weeks. After the first week, subjects underwent a sham exposure to filtered air with exercise, followed by bronchoalveolar lavage (BAL). Subjects were randomly assigned into supplement (one can vegetable juice, vitamins C and E daily) or placebo (orange soda, placebo pill daily) groups for 2 weeks. After the 2-week intervention, subjects were exposed to 0.4 ppm (784 microg/m(3)) ozone for 2 h with exercise followed by BAL. Blood samples were drawn before, immediately after and 3 h postexposure on each exposure day. The concentrations of nine carotenoids were determined by HPLC in BAL macrophages and plasma samples. RESULTS: Plasma concentrations of all the carotenoids that were present in the vegetable juice (except cis-beta-carotene) increased significantly in the supplemented group. Lung macrophage alpha-carotene concentrations increased significantly, lycopene isomers increased slightly, and all other carotenoids decreased (nonsignificantly) in the supplementation group following the intervention. Ozone exposure resulted in decreases in several carotenoids in plasma of the placebo group, but not in the supplemented group. CONCLUSIONS: Lung macrophage concentrations of carotenoids can be manipulated by diet. Ozone is a potent environmental oxidant that appears to reduce plasma carotenoids in nonsupplemented individuals.

Navy Asbestos Medical Surveillance Program, 1995-1999: demographic characteristics and smoking status.

A descriptive study of the Navy Asbestos Medical Surveillance Program is presented from data provided by the Navy Environmental Health Center in Norfolk, Virginia, with an emphasis on demographic characteristics and smoking. Analysis of 79,598 physical examinations for the period 1995 to 1999 revealed that Navy and Marine Corps civil service employees constituted 90% and Navy active duty personnel constituted 9%. Most personnel reported "no current exposure, have prior exposure" to asbestos (Navy active duty, 77%; civil service employees, 61%). Current smoking rates per year decreased for Navy active duty (from 34.6% to 28.7%) and civil service workers (from 26.0% to 21.6%), both reductions being significant for trend. Logistic regression for current smoking showed higher rates for Navy active duty and those with "direct" asbestos exposure, whereas those 50 years or older and of Asian ethnicity had lower smoking rates. These findings provide programmatic insights for the Asbestos Medical Surveillance Program and suggest areas for further study.

Evidence for clonal outgrowth of androgen-independent prostate cancer cells from androgen-dependent tumors through a two-step process.

Prostate cancers require androgen for growth but progress to an androgen-independent stage under the selective pressure of androgen ablation therapy. Here we describe a novel human prostate cancer xenograft (LAPC-9) propagated by serial passage in male severe combined immunodeficient mice that expresses prostate-specific antigen and wild-type androgen receptor. In response to castration, LAPC-9 cells undergo growth arrest and persist in a dormant, androgen-responsive state for at least 6 months. After prolonged periods of androgen deprivation, spontaneous androgen-independent outgrowths develop. Thus, prostate cancers progress to androgen independence through two distinct stages, initially escaping dependence on androgen for survival and, subsequently, for growth. Through the use of serial dilution and fluctuation analysis, we provide evidence that the latter stage of androgen independence results from clonal expansion of androgen-independent cells that are present at a frequency of about 1 per 10(5)-10(6) androgen-dependent cells. We conclude that prostate cancers contain heterogeneous mixtures of cells that vary in their dependence on androgen for growth and survival and that treatment with antiandrogen therapy provides selective pressure and alters the relative frequency of these cells, thereby leading to outgrowths of androgen-independent cancers.

Mitogen-activated protein kinase kinase kinase 1 activates androgen receptor-dependent transcription and apoptosis in prostate cancer.

Mitogen-activated protein (MAP) kinases phosphorylate the estrogen receptor and activate transcription from estrogen receptor-regulated genes. Here we examine potential interactions between the MAP kinase cascade and androgen receptor-mediated gene regulation. Specifically, we have studied the biological effects of mitogen-activated protein kinase kinase kinase 1 (MEKK1) expression in prostate cancer cells. Our findings demonstrate that expression of constitutively active MEKK1 induces apoptosis in androgen receptor-positive but not in androgen receptor-negative prostate cancer cells. Reconstitution of the androgen receptor signaling pathway in androgen receptor-negative prostate cancer cells restores MEKK1-induced apoptosis. MEKK1 also stimulates the transcriptional activity of the androgen receptor in the presence or absence of ligand, whereas a dominant negative mutant of MEKK1 impairs activation of the androgen receptor by androgen. These studies demonstrate an unanticipated link between MEKK1 and hormone receptor signaling and have implications for the molecular basis of hormone-independent prostate cancer growth.

A mechanism for hormone-independent prostate cancer through modulation of androgen receptor signaling by the HER-2/neu tyrosine kinase.

Prostate cancer progresses from a hormone-sensitive, androgen-dependent stage to a hormone-refractory, androgen-independent tumor. The androgen receptor pathway functions in these androgen-independent tumors despite anti-androgen therapy. In our LAPC-4 prostate cancer model, androgen-independent sublines expressed higher levels of the HER-2/neu receptor tyrosine kinase than their androgen-dependent counterparts. Forced overexpression of HER-2/neu in androgen-dependent prostate cancer cells allowed ligand-independent growth. HER-2/neu activated the androgen receptor pathway in the absence of ligand and synergized with low levels of androgen to 'superactivate' the pathway. By modulating the response to low doses of androgen, a tyrosine kinase receptor can restore androgen receptor function to prostate cancer cells, a finding directly related to the clinical progression of prostate cancer.

Mechanistic concepts in androgen-dependence of prostate cancer.

Androgen blockade is the mainstay of therapy in the clinical management of advanced prostate cancer. Recent progress on two fronts--the development of newer xenograft and transgenic models and a greater understanding of nuclear receptor signaling--has provided new insight into mechanisms of androgen-dependence in prostate cancer. This review centers on the concept that perturbations in androgen receptor signaling are likely to occur early in prostate cancer and play a critical role in progression to end stage hormone-refractory disease.

Women's health. The childbearing years and after.

Health and development planners have tended to see women primarily in context of their reproductive role. As a result, solutions to women's health needs have been restricted to expanding and improving maternal and child health systems. There has recently been a major shift in direction, largely because of the influence of the world conference on population and development held in Cairo in 1994. Dr Guiseppe Benagiano, director of the special programme of research, development and research training in human reproduction based at the WHO, says, "We need to remind ourselves constantly that reproductive health is not simply a biomedical issue but one with serious implications for our general health and by extension, for all our efforts in human social and economic development." The 1993 world development report on health identified the lack of a clear strategy for engaging women in health care and suggested that child health services, prenatal care, treatment of sexually transmitted diseases, and family planning services should be provided jointly at convenient times. In an example of this, the Chilean Institute of Reproductive Medicine now offers integrated family planning services at the same time as child health services, and Thailand is experimenting with mobile health clinics to reach women in their homes. As the proportion of elderly women increases, old age is increasingly being seen as a female issue. With the impact of urbanisation and industrialisation, more of these women are living isolated lives, often suffering from chronic debilitating diseases. In his opening statement to the global commission on women's health in April 1995 which focused on health conditions of women in old age, Dr Hiroshi Nakajima, the WHO's director general, said: "Our goal should not be solely to extend lives in the physical sense, but to ensure that the added years are worth living."

Serum micronutrients and prostate cancer in Japanese Americans in Hawaii.

Numerous dietary studies and several serum micronutrient studies have produced equivocal results on the relation of vitamins A and E to prostate cancer risk. To evaluate this association further, we conducted a nested case-control study in a cohort of 6860 Japanese-American men examined from 1971 to 1975. At the time of examination, a single blood specimen was obtained, and the serum was frozen. After a surveillance period of more than 20 years, 142 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 142 matched controls were measured by high-performance liquid chromatography for the following: total carotenoids, lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, beta-carotene, total retinoids, retinol, total tocopherols, alpha-tocopherol, delta-tocopherol, and gamma-tocopherol. Odds ratios for prostate cancer, based on quartiles of serum micronutrient levels, were determined using conditional logistic regression analysis. The odds ratio for the highest quartiles were 1.8 (95% confidence interval, 0.9-3.9) for beta-cryptoxanthin, 1.6 (0.8-3.5) for beta-carotene, 0.8 (0.4-1.5) for retinol, and 0.7 (0.3-1.5) for gamma-tocopherol, but none of the differences was statistically significant. For the other micronutrients, the results were also unremarkable. The findings of this study indicate that none of the micronutrients is strongly associated with prostate cancer risk.

Serum micronutrients and upper aerodigestive tract cancer.

Numerous dietary studies have found that vegetables and fruits protect against upper aerodigestive tract cancer. To evaluate the role of beta-carotene and other specific carotenoids, a nested case-control study using prediagnostic serum was conducted among 6832 American men of Japanese ancestry examined from 1971 to 1975. During a surveillance period of 20 years, the study identified 28 esophageal, 23 laryngeal, and 16 oral-pharyngeal cancer cases in this cohort. The 69 cases were matched to 138 controls. A liquid chromatography technique, designed to optimize recovery and separation of the individual carotenoids, was used to measure serum levels of lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, beta-carotene, retinol, retinyl palmitate, and alpha-, delta-, and gamma-tocopherol. With adjustment for cigarette smoking and alcohol intake, we found that alpha-carotene, beta-carotene, beta-cryptoxanthin, total carotenoids and gamma-tocopherol levels were significantly lower in the 69 upper aerodigestive tract cancer patients than in their controls. Trends in risk by tertile of serum level were significant for these five micronutrients. These significant trends persisted in cases diagnosed 10 or more years after phlebotomy for the three individual carotenoids and total carotenoid measurements. The odds ratios for the highest tertile were 0.19 (95% confidence interval, 0.05-0.75) for alpha-carotene, 0.10 (0.02-0.46) for beta-carotene, 0.25 (0.06-1.04) for beta-cryptoxanthin, and 0.22 (0.05-0.88) for total carotenoids. When the cases were separated into esophageal, laryngeal, and oral-pharyngeal cancer, both alpha-carotene and beta-carotene were consistently and strongly associated with reduced risk at each site. The findings suggest that alpha-carotene and other carotenoids, as well as beta-carotene, may be involved in the etiology of upper aerodigestive tract cancer.

Development of engineered stationary phases for the separation of carotenoid isomers.

A variety of bonded phase parameters (endcapping, phase chemistry, ligand length, and substrate parameters) were studied for their effect on column retention and selectivity toward carotenoids. Decisions were made on how each of these variables should be optimized based on the separation of carotenoid and polycyclic aromatic hydrocarbon test probes. A column was designed with the following properties: high absolute retention, enhanced shape recognition of structured solutes, and moderate silanol activity. These qualities were achieved by triacontyl (C30) polymeric surface modification of a moderate pore size (approximately 20 nm), moderate surface area (approximately 200 m2/g) silica, without subsequent endcapping. The effectiveness of this "carotenoid phase" was demonstrated for the separation of a mixture of structurally similar carotenoid standards, an extract of a food matrix Standard Reference Material, and a beta-carotene dietary supplement under consideration as an agent for cancer intervention/prevention.

Does beta-carotene explain why reduced cancer risk is associated with vegetable and fruit intake?

Increased intake of vegetables, fruits, and carotenoids and elevated blood levels of beta-carotene are consistently associated with reduced risk of lung cancer in epidemiologic studies. Epidemiologic research also suggests that carotenoids may reduce the risk of other cancers, although the evidence is less extensive and consistent. The simplest explanation is that beta-carotene is protective. However, the possible roles of other carotenoids, other constituents of vegetables and fruits, and associated dietary patterns have not been adequately explored. To evaluate these alternative hypotheses, we are undertaking three lines of research. (a) With dietary data from the 1987 National Health Interview Survey and the 1982-1984 Epidemiologic Follow-up of the first National Health and Nutrition Examination Study, we have determined which food groups and nutrients are highly correlated with vegetable and fruit intake. (b) We have developed and characterized a liquid chromatography method for optimal recovery and resolution of the common carotenoids in blood, specifically lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, and beta-carotene. (c) In a population-based case-control study of lung cancer in white men in New Jersey, we are assessing whether estimates of the intake of the individual carotenoids might produce stronger inverse associations than estimates of provitamin A carotenoids based on current food composition tables.

Depressed response of plasma iron and zinc to endotoxin and LEM in STZ-diabetic rat.

Laboratory and epidemiological evidence indicate that the enhanced flux of iron and zinc from the plasma to the storage compartments, such as liver, serves as a protective host response to combat infection. Studies were performed to determine the status of this nonspecific immune response in the diabetic animal, since it is commonly held that the diabetic has an increased incidence and susceptibility to infection. Normal rats and rats previously rendered diabetic by streptozotocin (STZ) were injected with either saline or Escherichia coli endotoxin, and plasma levels of zinc, iron, and copper were monitored 8 hr thereafter. Diabetic rats reduced their plasma zinc and iron levels by 35 and 25%, respectively, in response to endotoxin injection whereas control rats had a 70% decrease in zinc and a 46% depression in iron. Insulin administration to the diabetic rats restored the ability to decrease plasma zinc and iron to the same degree as control rats. Plasma copper did not change in any group. Further investigation suggested that the defect in trace metal response occurred after the secretion of leukocytic endogenous mediator (LEM) in the inflammatory response pathway. It is concluded that STZ-diabetic rats have a diminished ability to decrease plasma zinc and iron in response to endotoxin, and that this defect is due to an ineffective response of target tissues to the effects of leukocytic endogenous mediator. Furthermore, it is postulated that the hyperinsulinemia associated with the stress of infection functions to lower plasma zinc and, possibly, iron, thereby allowing the host to better combat infection.

Zinc, iron, and copper absorption in the streptozotocin-diabetic rat.

Altered tissue levels of trace metals have been reported in streptozotocin-diabetic (STZ) rats. To determine whether increased hepatic and renal levels of Cu and Zn were associated with enhanced intestinal absorption, trace metal absorption was studied in control (C) and STZ rats using dietary balance and in situ ligated-loop techniques. The apparent daily absorption of dietary Zn and Cu per 100 g body wt was threefold higher in STZ than C rats. In comparison, dietary Fe absorption per day was not altered. Increased Zn absorption was closely correlated with diabetes-associated polyphagia. The initial rate of injected 65Zn excretion was more rapid in STZ rats, although the rate of excretion beyond day 7 was similar from C and STZ animals. The quantity of Zn, Fe, and Cu absorbed per 20 cm duodenal loop was similar for C and STZ rats. Zn, Fe, and Cu absorption per gram dry mucosa were reduced 45-53% in STZ rats due to the 50% increase in mucosal mass. Moreover, the quantity of radioisotopes accumulated per gram dry mucosa and the concentration of metallothionein per gram mucosal cytosol protein were similar in C and STZ animals. Together, these data demonstrate that increased absorption of dietary Zn and Cu is in part responsible for accumulation of these elements in STZ tissues and suggest altered metal transport at the luminal (brush border) surface of the intestinal epithelium.