Effect of an omega-3 fatty acid containing lipid emulsion alone and in combination with 5-fluorouracil (5-FU) on growth of the colon cancer cell line Caco-2

Summary. Background: In this study we examined the effects of a fish oil-based lipid emulsion (FO) rich in omega-3 fatty acids, which is used in humans as a component of parenteral nutrition, on the growth of the colon cancer cell line Caco-2. Aim of the study: The aim of the present study was to investigate whether the FO influences growth and chemosensitivity of the colon cancer cell line Caco-2. FO was tested alone and in combination with the anticancer drug 5-fluorouracil (5-FU). Methods: Cell numbers were determined with crystal violet staining, cell cycle distribution was assessed using a flow cytometer and apoptosis was visualized by staining nuclei with diamino-phenylindole hydrochloride. Results: FO inhibited growth of Caco-2 cells in a time and dose dependent manner. FO treatment evoked apoptosis as confirmed by cell morphology. Cell cycle analysis identified an accumulation of cells in the G₂/M phase after incubation with FO. The combined treatment of the cells with FO and 5-FU resulted in a significant enhancement of the growth inhibition seen after exposure to either substance alone. Treatment of the cells with 5-FU specifically blocked the cell cycle in the S phase. The combined treatment of 5-FU with FO showed a further increase in the accumulation of cells in the S phase. Conclusions: In conclusion, FO has a potent antiproliferative effect on Caco-2 cells, at least in part, due to a decrease in the progression of the cell cycle and the induction of apoptosis. The combination of FO with 5-FU results in an additive growth inhibitory effect.     

Neurofibrillary degeneration of the Alzheimer-type: an alternate pathway to neuronal apoptosis?

Neuronal death is a process which may be either physiological or pathological. Apoptosis and necrosis are two of these processes which are particularly studied. However, in neurodegenerative disorders, some neurons escape to these types of death and "agonize" in a process referred to as neurofibrillary degeneration. Neurofibrillary degeneration is characterized by the intraneuronal aggregation of abnormally phosphorylated microtubule-associated Tau proteins. A number of studies have reported a reactivation of the cell cycle in the neurofibrillary degeneration process. This reactivation of the cell cycle is reminiscent of the initiation of apoptosis in post-mitotic cells where G1/S markers including cyclin D1 and cdk4/6, are commonly found. However, in neurons exhibiting neurofibrillary degeneration, both G1/S and G2/M markers are found suggesting that they do not follow the classical apoptosis and an aberrant cell cycle occurs. This aberrant response leading to neurofibrillary degeneration may be triggered by the sequential combination of three partners: the complex Cdk5/p25 induces both apoptosis and the "abnormal mitotic Tau phosphorylation". These mitotic epitopes may allow for the nuclear depletion of Pin1. This latter may be responsible for escaping classical apoptosis in a subset of neurons. Since neurofibrillary degeneration is likely to be a third way to die, molecular mechanisms leading to changes in Tau phosphorylation including activation of kinases such as cdk5 or other regulators such as Pin1 could be important drug targets as they are possibly involved in early stages of neurodegeneration.     

Oral cytology assessment by flow cytometry of DNA adducts, aneuploidy, proliferation and apoptosis shows differences between smokers and non-smokers

Oral cytology and morphometric staining is used to identify malignant keratinocytes in oral premalignant or malignant lesions. To detect and to begin to assess changes in oral keratinocytes exposed to tobacco-derived carcinogens, which are at risk for malignant transformation, a novel method is required. The approach uses oral cytology harvested oral keratinocytes analyzed using flow cytometry (FC) for changes in DNA content, damage, cell cycle and apoptosis. Six smoker and six non-smoker oral keratinocytes were evaluated using flow cytometry in the form of laser scanning cytometry (LSC) and laser microdissection (LMD). Among smokers compared to non-smokers, the method detected and assessed DNA damage from tobacco smoke exposure quantifying an enhanced formation of DNA adducts, such as, 8-hydroxy-2′-deoxyguanine (8-OHdG) which creates oxidation lesions and benzo[a]pyrene(B[a]P), which produces a B[a]P)-N2-dG bulky adduct. Increased DNA content, aneuploidy, percentage of cells in synthesis (S) and G₂+Mitosis (M), and apoptosis were recorded. Tissue and cell controls were used to verify these relationships. Data suggested healthy smokers were at increased risk for malignant transformation of oral keratinocytes because of the changes stated above. Using identical methods, keratinocytes exposed to the tobacco derived carcinogen, B[a]P parallel results obtained from smoke exposure indicating a direct link. Flow cytometric evaluation of oral cytology harvested keratinocytes can be used to measure exposure to tobacco carcinogens, and possibly establish a link to premalignant and malignant transformation before a lesion is noted.     

Lack of effect of isoflavonic phytoestrogen intake on leptin concentrations in premenopausal and postmenopausal women

Objective: To assess the effect of soy isoflavone ingestion on plasma leptin concentrations in premenopausal and postmenopausal women.

Design: Randomized, crossover studies, with blinding of participants and laboratory personnel.

Setting: Procedures involving free-living individuals were carried out at the University of Minnesota General Clinical Research Center.

Patient(s): Fourteen regularly cycling premenopausal women, and 18 postmenopausal women.

Intervention(s): Each premenopausal participant consumed, on a daily basis, each of three soy protein powders containing different levels of isoflavones for three menstrual cycles plus 9 days, with plasma samples collected every other day the last 6 weeks of each diet period. Similarly, each postmenopausal participant consumed each of the three powders for 93 days, with plasma samples collected daily on days 64 to 66 and 92 to 94 of each diet period. The powders, dosed on a per-kilogram body weight basis, provided mean isoflavone intakes of 8, 65, and 130 mg/day, for the control, low-isoflavone, and high-isoflavone diet periods, respectively.

Main Outcome Measure(s): Plasma leptin concentrations.

Result(s): Isoflavone intake had essentially no effect on leptin concentrations in either premenopausal or postmenopausal participants. Concentrations in the premenopausal women were higher during the periovulatory and midluteal phases as compared to the early follicular and midfollicular phases.

Conclusion(s): Despite the well-documented effect of estrogens to enhance leptin production, even high levels of isoflavone consumption do not alter leptin concentrations in women. Further studies are needed to more precisely delineate the nature of estrogenic and/or antiestrogenic effects of isoflavones in humans.     

Influence of menstrual cycle on NK activity

Natural killer (NK) cells are CD3⁻ CD56⁺ and/or CD16⁺ cytotoxic lymphocytes that mediate first-line defense against various types of target cells without prior immunization. To assess the effect of the menstrual cycle and gender on NK activity we evaluated 30 healthy women (mean age 28.1 years, range 21–39) in follicular and luteal phases, 29 postmenopausal women (mean age 58.8 years, range 42–72) and 48 healthy men (mean age 31.6 years, range 21–40). In a flow cytometric test of NK activity, peripheral blood mononuclear effector cells were mixed with K562 targets cells labeled with DiO (3,3′-dioctadecyloxacarbocyanine perchlorate) at effector:target cell ratios of 40, 20, 10 and 5:1. Dead cells were stained with propidium iodide and results were expressed as lytic units per 10⁷ cells. In addition, progesterone levels were determined in the luteal phase of the menstrual cycle of healthy women by a chemiluminescence assay. Our results showed that (1) NK cytotoxicity was higher in the follicular than in the luteal phase of the menstrual cycle (P<0.0001); (2) postmenopausal women and men showed NK activity similar to women in the folicular phase but higher than women in the luteal phase of the menstrual cycle (P<0.05); and (3) there was no correlation between NK activity and levels of progesterone. The data suggest that progesterone does not influence NK activity directly and that other factors may explain the reduction of NK activity in the luteal phase of the menstrual cycle.     

乳腺乳头状瘤病中4种细胞周期调控因子的检测及临床意义

目的　观察不同程度的乳腺乳头状瘤病中 4种细胞周期调控因子蛋白的表达及临床意义 ,为临床上乳腺癌癌前病变的有效诊治提供客观指标。方法　通过免疫组织化学S P法在乳腺轻度、中度、重度乳头状瘤病及导管内癌组各 4 8例患者中检测细胞周期素D1、p16、E2F 1、Rb基因蛋白表达情况。结果　细胞周期素D1、p16、E2F 1、Rb 4种因子表达的阳性率和表达强度分别在 4组间的差异均有显著意义 (χ2 分别为 16 70、2 0 74、4 0 34、4 2 32 ;19 12、2 9 4 7、4 5 0 8、4 6 92 ,均P <0 0 1;在中度和重度乳头状瘤病组间差异也有显著意义 (均P <0 0 5 ) ;E2F 1或Rb在重度乳头状瘤病和导管内癌组间差异有显著意义 (均P <0 0 1) ,但细胞周期素D1或 p16在这两组间差异无显著意义 (均P >0 0 5 ) ;细胞周期素D1及E2F 1表达与由轻至重的乳头状瘤病乃至导管内癌呈正相关 ,相反p16及Rb与之呈负相关 ;Rb阴性或低表达时中度乳头状瘤病发展到重度乳头状瘤病的危险度最大。结论细胞周期素D1等 4种调控因子与乳腺癌的发生发展过程有密切的相关性。E2F 1和Rb可作为重度乳头状瘤病和导管内癌鉴别诊断的参考指标。Rb还有助于筛选重度和中度乳头状瘤病中的高危病例。     

A pilot study on a gene-hormone interaction in female suicide attempts

Abstract. This one-year naturalistic study included all suicide attempters in a catchment area. In the first published set of analyses, an association between menses and suicide attempts was replicated. According to the polymorphism of the serotonin transporter promoter area, the subjects can be classified as S individuals (s/s or s/l) or L individuals (l/l). In the second published set of analyses, L females appeared protected from suicide attempts since they were underrepresented among female (and not male) attempters. This new, unpublished third set of analyses tested for an interaction between the same polymorphism and low hormonal activity (during menses and menopause). In fertile female attempters, the proportion of L women in the menses (41%, 7/17) was significantly higher than expected in the population (15.5 %) and almost significantly higher than in S female attempters (22%,19/87). L females were also overrepresented in postmenopausal attempters. Despite sample size limitations, this gene-hormone interaction needs to be further investigated in female suicide attempters.     

Modulation of Intraocular Pressure by Unilateral and Forced Unilateral Nostril Breathing in Young Healthy Human Subjects

PURPOSE: To determine the effects of unilateral right/left nostril breathing (URNB/ULNB) and forced unilateral right/left nostril breathing (FURNB/FULNB) on intraocular pressure (IOP) and to examine the differences in the IOP during the various phases of nasal cycle. METHODS: Young healthy volunteers of either sex aged between 19-24 years, participated in the sessions using URNB/ULNB (n = 52) and FURNB/FULNB (n = 28). The nostril dominance was calculated from signals recorded on the PowerLab equipment, representing pressure changes at the end of the nostrils during respiration. The IOP was measured with Tono-Pen. The subjects were divided into 4 groups viz. right nostril dominant (RND), left nostril dominant (LND), transitional right nostril dominant (TRND) and transitional left nostril dominant (TLND) groups. The IOP data 'before and after' URNB/ULNB or FURNB/FULNB were compared by using paired t-test. The baseline data of IOP between the groups were analysed by using independent samples t-test. RESULTS: The URNB decreased the IOP in the LND and TLND (p < 0.01) and also in the RND (p < 0.05) groups but not significantly in the TRND group. The ULNB decreased the IOP in the RND group (p < 0.01) only. The FURNB significantly reduced the IOP (p < 0.05) only in the LND and RND groups. The FULNB decreased the IOP but not significantly. The baseline IOP did not differ significantly between the LND, RND, TLND and TRND groups. CONCLUSION: The URNB/FURNB reduced the IOP, while ULNB/FULNB failed to increase the IOP significantly. It is suggested that the lowering of IOP by URNB indicated sympathetic stimulation.     

Cell cycle checkpoint efficiency and cellular response to paclitaxel in prostate cancer cells

BACKGROUND: Defects in the cell cycle machinery of prostate cancer cells might impair the efficiency of cell cycle checkpoints and affect the cell response to chemotherapeutic drugs. We examined the relationship between the status of microtubule damage-activated checkpoints and the response of hormone-refractory prostate cancer cells to paclitaxel. METHODS: The two cell lines DU145 and PC3 harboring defects at proteins involved in the regulation of checkpoints activated by microtubule damage were examined for cell sensitivity, apoptotic response, and efficiency of checkpoints in response to paclitaxel. RESULTS: In spite of a comparable sensitivity to the antiproliferative effects of paclitaxel, DU145 and PC3 cells exhibited different cell cycle control at checkpoints activated by microtubule damage. A transient mitotic arrest was induced by the taxane in both cell lines. However, PC3 cells underwent a rapid mitotic slippage and displayed a defective postmitotic checkpoint as evidenced by the appearance of polyploid cells. In this cell line, paclitaxel-induced cell death was a slow and delayed event, occurring also after S-phase re-entry. The mitotic checkpoint appeared to be more stringent in DU145 cells compared to PC3 cells. Moreover, despite the expression of mutated proteins involved in the prevention of DNA endoreduplication (p53, pRb, and p16(INK4A)), these cells did not progress into the cell cycle but efficiently underwent apoptosis by 24 hr. Such a response of DU145 cells was associated with phosphorylation of the p21(WAF1) protein. CONCLUSIONS: These observations evidence that activation of checkpoints following microtubule damage in prostate cancer may be regulated through complex mechanisms possibly involving p21(WAF1). Our findings support that the status of cell cycle checkpoints might affect the modality of cell death. However, the relevance of the mode of cell death for the sensitivity to taxanes remains to be determined.