Biomedical subjects

O Kucuk

Publications and source records attributed to O Kucuk.

At least 37 records · Page 2Linked to original sources

PubMed2001

Phase II randomized clinical trial of lycopene supplementation before radical prostatectomy.

An inverse association has been observed between dietary intake of lycopene and the risk of prostate cancer. We investigated the effects of lycopene supplementation in patients with prostate cancer. Twenty-six men with newly diagnosed, clinically localized (14 T(1) and 12 T(2)) prostate cancer were randomly assigned to receive 15 mg of lycopene (n = 15) twice daily or no supplementation (n = 11) for 3 weeks before radical prostatectomy. Biomarkers of differentiation and apoptosis were assessed by Western blot analysis on benign and malignant parts of the prostate gland. Prostatectomy specimens were entirely embedded, step-sectioned, and evaluated for pathological stage, Gleason score, volume of cancer, and extent of high-grade prostatic intraepithelial neoplasia. Plasma levels of lycopene, insulin-like growth factor-1 (IGF-1), IGF binding protein-3, and prostate-specific antigen were measured at baseline and after 3 weeks of supplementation or observation. Eleven (73%) subjects in the intervention group and two (18%) subjects in the control group had no involvement of surgical margins and/or extra-prostatic tissues with cancer (P = 0.02). Twelve (84%) subjects in the lycopene group and five (45%) subjects in the control group had tumors <4 ml in size (P = 0.22). Diffuse involvement of the prostate by high-grade prostatic intraepithelial neoplasia was present in 10 (67%) subjects in the intervention group and in 11 (100%) subjects in the control group (P = 0.05). Plasma prostate-specific antigen levels decreased by 18% in the intervention group, whereas they increased by 14% in the control group (P = 0.25). Expression of connexin 43 in cancerous prostate tissue was 0.63 +/- 0.19 absorbance in the lycopene group compared with 0.25 +/- 0.08 in the control group (P = 0.13). Expression of bcl-2 and bax did not differ significantly between the two study groups. IGF-1 levels decreased in both groups (P = 0.0002 and P = 0.0003, respectively). The results suggest that lycopene supplementation may decrease the growth of prostate cancer. However, no firm conclusions can be drawn at this time because of the small sample size.

Administration, Oral↗

PubMed2000

Weekly 1-hour infusion of paclitaxel. Clinical feasibility and efficacy in patients with hormone-refractory prostate carcinoma.

BACKGROUND: Preclinically, paclitaxel given according to an intense bolus schedule has significant antitumor activity against human prostate carcinoma cell lines in SCID mice. The authors evaluated the feasibility and efficacy of weekly 1-hour infusion of paclitaxel in patients with metastatic hormone-refractory prostate carcinoma (HRPC). METHODS: A total of 18 patients with progressive metastatic HRPC were enrolled. Patients had to have no prior chemotherapy. Paclitaxel was infused weekly at a dose of 150 mg/m(2) over 1 hour for 6 weeks every 8 weeks. RESULTS: Eighteen patients with a median age of 68.5 years and a median prostate specific antigen (PSA) level of 82 ng/mL (range, 2.17-3196 ng/mL) were enrolled. The median number of prior hormone treatments was 2, and 12 patients on antiandrogens completed antiandrogen withdrawal. Ten of eighteen patients had bone-only metastasis and eight had metastasis to bone with lymph node and/or visceral metastasis. Seventeen patients received a total of 31 cycles (157 courses) and 1 patient refused chemotherapy. All patients were included in response evaluation. Of the 8 [corrected] patients with measurable disease, 4 achieved a major response, with 1 complete response (in the lung) and 3 partial responses (1 in the liver and 2 in the lymph nodes). Seven of eighteen patients (39%) had a PSA decline of >/=50%. The major high grade toxicity was peripheral neuropathy, with 6 patients (35%) developing Grade 3 toxicity. CONCLUSIONS: Weekly 1-hour paclitaxel has activity in patients with HRPC. The major toxicity is peripheral neuropathy. The minimal myelosuppressive effects make a modified schedule (lower doses on the same schedule or a shorter schedule of the same dose) attractive for future combination chemotherapy trials.

Aged↗

PubMed2000

Phase II trail of didemnin B in previously treated non-Hodgkin's lymphoma: an Eastern Cooperative Oncology Group (ECOG) Study.

Patients with non-Hodgkin's lymphoma (NHL) who fail initial therapy have a poor prognosis. We conducted a phase II study to determine the efficacy and toxicity of didemnin B, a non-myelosuppressive marine compound, in patients with NHL who relapsed or progressed after receiving one or two previous chemotherapy regimens. Fifty-one eligible patients were registered on this phase II study. Twenty-nine patients had intermediate or high grade (IG/HG) disease and 22 patients had low grade (LG) disease. Twenty-five patients received didemnin B at a dose of 6.3 mg/m2 and the remainder received 5.6 mg/m2, administered intravenously every 28 days. The patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 and biopsy-proven relapsed disease. Objective responses were observed in two (7%) patients (one complete remission [CR] and one partial remission [PR]) with IG/HG disease and five (23%) patients (one CR and four PR) with LG disease. Patients with IG/HG disease had a median time to treatment failure (TTF) of 1.6 months and a median survival of 8.0 months. In contrast, the group with LG disease had a median TTF of 4.6 months and a median survival of 2.7 years. There were five grade V, 12 grade IV, and 57 grade III toxicities. Didemnin B appears to have modest activity in low grade NHL. However, the drug has considerable toxicity in this population of patients.

Adult↗

PubMed2000

Phase II trial of cisplatin, etoposide, and 5-fluorouracil in advanced non-small-cell lung cancer: an Eastern Cooperative Oncology Group Study (PB586).

Advanced non-small-cell lung cancer (NSCLC) remains an incurable disease despite significant progress in chemotherapy. We conducted a phase II clinical trial to investigate the efficacy and toxicity of a cisplatin, etoposide, and 5-fluorouracil (5-FU) combination in advanced metastatic and/or recurrent NSCLC. Forty patients with advanced, recurrent, or metastatic, measurable NSCLC were treated with cisplatin, 60 mg/m2 intravenously (i.v.) on day 1; etoposide, 120 mg/m2/day i.v. on days 1, 2, and 3; and 5-FU. 1,000 mg/m2/day i.v. continuous infusion on days 1 through 5. Treatment was administered in 4-week cycles. Thirty patients had distant metastases and were previously untreated, and 10 patients had recurrent disease after prior treatment with either surgery (1 patient), radiation therapy (5 patients), or both treatments (4 patients). Twenty-nine patients were evaluable for response. Seven (24%) patients achieved a partial remission (PR), 18 (62%) had stable disease (SD), and 8 (14%) had progressive disease (PD). Overall median survival was 7.9 months (range, 0.4-27.4 months). Patients who achieved a PR had a median survival of 23.5 months (9.3-27.4 months). In contrast, patients with SD had a median survival of 9.9 months (2.5-25.3 months), and patients with PD had a median survival of 2.1 months (1-9.3 months). Median duration of response of 27.1 weeks (4.9-76.5 weeks) for patients with PR, and time to progression was 13.4 weeks (3.7-54.5 weeks) for patients with SD. Toxicity was primarily hematologic and gastrointestinal, and there were three deaths due to infection. The combination of cisplatin, 5-FU, and etoposide as administered in this study appears to have considerable toxicity and does not appear to be superior to other cisplatin-containing regimens used for the treatment of advanced NSCLC.

Adult↗

PubMed2000

Phase II trial of menogaril in patients with previously treated multiple myeloma or chronic lymphocytic leukemia.

Menogaril is a semisynthetic anthracycline with relative lack of cardiotoxicity. Ten patients with multiple myeloma (MM), seven patients with chronic lymphocytic leukemia (CLL), and one patient with diffuse well-differentiated lymphocytic lymphoma (DWDL) were treated with menogaril, 160 mg/m2 (for MM) or 200 mg/m2 (for CLL/DWDL), given as a 2-hour intravenous infusion, repeated every 28 days. All patients except one with CLL had been previously treated with one chemotherapy regimen and had either not responded or had relapsed after a response to prior treatment. There were no objective responses to treatment. Among the six evaluable patients with MM, two had stable disease with subjective improvement in symptoms for five to 25 cycles, and among the eight patients with CLL/DWDL, five patients remained stable for two to eight cycles on treatment. The remainder of the patients had progressive disease after one to two cycles of chemotherapy. Five grade 4 hematologic toxicities were observed. There was one fatal neutropenic sepsis. Menogaril, as administered in this study, does not appear to have significant activity in patients with previously treated MM or CLL.

Aged↗

PubMed2000

Inhibition of prostate specific antigen expression by genistein in prostate cancer cells.

Recent studies have provided convincing evidence for the role of soy-isoflavones, particularly genistein, in the inhibition of prostate cancer cell growth. Prostate specific antigen (PSA) is a biological marker used to detect and monitor the treatment of prostate cancer patients. Previous studies have documented that isoflavones can inhibit the secretion of PSA in the androgen-dependent prostate cancer cell line, LNCaP, however, the effects of genistein on androgen-independent PSA expression has not been explored. In this study, we have utilized a prostate cancer cell line, VeCaP, which expresses PSA in an androgen-independent manner, to determine the effects of genistein on cell proliferation and PSA expression. Here we show that genistein inhibits cell growth similarly in both the LNCaP and VeCaP cell lines, but has differential effects on PSA expression. We demonstrate using concentrations of genistein that have been detected in the serum of humans consuming a soy-rich diet, that genistein decreases PSA mRNA, protein expression and secretion. Conversely, only high concentrations of genistein inhibited PSA expression in VeCaP cells. Additionally, we have demonstrated that genistein inhibits cell proliferation independent of PSA signaling pathways, providing further evidence to support the role of genistein as a chemopreventive/therapeutic agent for prostate cancer irrespective of androgen responsiveness.

Antineoplastic Agents↗

PubMed1999

Paclitaxel, cisplatin, and 5-fluorouracil for patients with advanced or recurrent squamous cell carcinoma of the head and neck.

BACKGROUND: The combination of cisplatin and 5-fluorouracil (5-FU) is considered standard therapy for patients with recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN). Paclitaxel has exhibited single-agent activity in patients with this disease. The authors conducted this study to evaluate the feasibility and efficacy of combining paclitaxel with cisplatin and 5-FU for patients with advanced or recurrent SCCHN. METHODS: Patients with recurrent, metastatic, or locally advanced SCCHN who had measurable or evaluable disease and no prior chemotherapy were eligible. The starting dose level consisted of paclitaxel 135 mg/m(2) on Day 1, cisplatin 75 mg/m(2) on Day 2, and 5-FU 1 gm/m(2)/day on Days 2-6. Due to Grade 4 mucositis, dose level 1 of 5-FU was reduced to 800 mg/m(2)/day on Days 2-6 (for 7 patients), and subsequently the 5-FU dose was adjusted to 1 gm/m(2)/day on Days 2-5 (for 17 patients). RESULTS: Twenty-five patients were enrolled, with a median age of 60 years and a median Southwest Oncology Group performance status of 1. Of the 25 patients, 16 had recurrent disease, 3 had metastatic disease at diagnosis, and 6 had untreated locally advanced SCCHN. Ninety-nine courses of therapy were administered, with a median of 5 courses. Major toxicities were neutropenia and mucositis. Significant neurotoxicity or nephrotoxicity were not observed. There were two treatment-related deaths (one each due to mucositis and neutropenic pneumonia), and these precluded further dose escalation. Fifteen of the 25 patients (60%) achieved a major response. Of significance is the response rate of 58% (11 of 19 patients) in those with recurrent or metastatic disease who had a duration of response ranging from 3 to 19+ months. Two of these 19 patients continue to be in remission of 19+ and 15+ months' duration, respectively. The median survival for patients with recurrent or metastatic disease was 6 months (range, 1-26 months), with a 1-year survival rate of 37%. CONCLUSIONS: The dose and schedule for the combination of paclitaxel, 5-FU, and cisplatin as determined in this study are feasible, with encouraging outcomes and activity in patients with recurrent or metastatic SCCHN. The results of this trial warrant larger-scale evaluation to determine the role of this combination in the management of patients with this disease.

Adult↗

PubMed1999

Expression of regeneration and tolerance factor on B cell chronic lymphocytic leukemias: a possible mechanism for escaping immune surveillance.

Regeneration and tolerance factor (RTF) is a protein expressed on developing tissue such as the thymus and the placenta. RTF has been reported to down-regulate cell-mediated immune responses. To examine the potential role of tumor-derived RTF to suppressing antitumor responses, we analyzed a panel of seven B cell tumor lines for the membrane RTF using a fluorescein isothiocyanate (FITC) conjugated monoclonal antibody, which reacts with membrane RTF. All the B cell tumor lines we examined express RTF on the cell surface. We also tested conditioned media from these B cell lines for their ability to suppress IL-2R expression on activated cells. Conditioned media from each B cell line suppressed IL-2R expression on activated Jurkat T cells and activated peripheral blood mononuclear cells. A monoclonal antibody to the biologically active portion of RTF reversed this suppressive activity. Finally, the tumor cell population from patients with chronic lymphocytic leukemia was found to express cell surface RTF. Thus, RTF expression could be a new mechanism used by tumor cells to escape immune surveillance.

Coculture Techniques↗

PubMed1999

Phase II study of cisplatin and 5-fluorouracil in previously treated metastatic breast cancer: an Eastern Cooperative Oncology Group study (PA 185).

PURPOSE: The present study was conducted to investigate the efficacy and toxicity of a cisplatin and 5-fluorouracil (5-FU) combination in previously treated advanced breast cancer. METHODS: Thirty-six women with recurrent metastatic breast cancer were entered on a phase II study of 5-FU 1000 mg/m2/day given intravenously as a continuous infusion on days 1-3 and cisplatin 30 mg/m2/day given intravenously over 1 h on days 2-4, repeated every 21 days. All subjects had received one previous chemotherapy regimen for metastatic disease and either progressed during treatment or relapsed after responding to previous chemotherapy. Fourteen patients had also received previous adjuvant chemotherapy, 17 patients had previous radiation therapy, and 29 patients had previous hormonal therapy. RESULTS: Among 32 response-evaluable patients, there were 10 partial remissions (31%) and 1 complete remission (3%), with an overall objective response rate of 34%. Median duration of response was 4 months. Median survival was 10.5 months for responders and 9.5 months for the entire group. Toxicity was mild to moderate in most patients. Overall twelve patients experienced grade 3 toxicity (10 hematologic, 1 mucositis, and 2 nausea). There were no grade 4 or 5 toxicities. CONCLUSION: Infusional cisplatin and 5-FU is a well tolerated and active regimen in women with previously treated advanced breast cancer.

Adenocarcinoma↗

PubMed1999

Folic acid inhibition of EGFR-mediated proliferation in human colon cancer cell lines.

Although accumulating evidence suggests a chemopreventive role for folic acid in colon cancer, the regulation of this process in unknown. We hypothesize that supplemental folic acid exerts its chemopreventive role by inhibiting mucosal hyperproliferation, an event considered to be central to the initiation of carcinogenesis in the gastrointestinal tract. The present investigation examines the effect of supplemental folic acid on proliferation of Caco-2 and HCT-116 colon cancer cell lines. Furthermore, because certain tyrosine kinases, particularly epidermal growth factor receptor (EGFR), play a role in regulating cell proliferation, we also examined the folic acid-induced changes in tyrosine kinase activity and expression of EGFR. In Caco-2 and HCT-116 cells, maintained in RPMI 1640 medium containing 1 microg/ml folic acid, we observed that the supplemental folic acid inhibited proliferation in a dose-dependent manner. Pretreatment of HCT-116 and Caco-2 cell lines with supplemental folic acid (1.25 microg/ml) completely abrogated transforming growth factor-alpha (TGF-alpha)-induced proliferation in both cell lines. Tyrosine kinase activity and the relative concentration of EGFR were markedly diminished in both cell lines following a 24-h exposure to supplemental folic acid. The folic acid-induced inhibition of EGFR tyrosine kinase activity in colon cancer cell lines was also associated with a concomitant reduction in the relative concentration of the 14-kDa membrane-bound precursor form of TGF-alpha. In conclusion, our data suggest that supplemental folic acid is effective in reducing proliferation in two unrelated colon cancer cell lines and that EGFR tyrosine kinase appears to be involved in regulating this process.

Anticarcinogenic Agents↗

PubMed1999

Genistein inhibits NF-kappa B activation in prostate cancer cells.

Prostate cancer is the second leading cause of cancer-related deaths in men in the United States. Epidemiological studies indicate that susceptibility to prostate cancer may be partly due to environmental influences, especially diet. An association has been shown between decreased prostate cancer risk and mortality with increased consumption of soy products, resulting in increased levels of isoflavones. We previously demonstrated that the soy isoflavone genistein inhibits cell growth and induces apoptosis in prostate cancer cells. To further elucidate the molecular mechanism by which genistein elicits its apoptotic effect, we investigated the role of a transcription factor, nuclear factor-kappa B (NF-kappa B), in the androgen-sensitive cell line LNCaP and the androgen-insensitive cell line PC3. Here we show that genistein decreases NF-kappa B DNA binding and abrogates NF-kappa B activation by DNA-damaging agents, H2O2 and tumor necrosis factor-alpha, in prostate cancer cells regardless of androgen sensitivity. Additionally, we have demonstrated that genistein reduces phosphorylation of the inhibitory protein I kappa B alpha and blocks the nuclear translocation of NF-kappa B, prohibiting DNA binding and preventing NF-kappa B activation. These results provide a mechanism by which genistein induces apoptosis in prostate cancer cells: the inactivation of NF-kappa B. Furthermore, genistein's ability to abrogate NF-kappa B activation by DNA-damaging agents strongly supports genistein's role as a chemopreventive agent.

Anticarcinogenic Agents↗

PubMed1998

Phase changes in membrane lipids in sickle red cell shed-vesicles and sickle red cells.

Lipid phase transformations may occur in the membranes of sickle red cell shed-vesicles and sickle red cells. The presence of such phase changes could be important in sickle cell disease since membrane phase changes appear to contribute to the generation of antiphospholipid antibodies that are thrombophilic and occur in sickle cell disease. In the present study, we have evaluated sickle red cell shed-vesicles and sickle red cells for the presence of non-bilayer lipid phases using 31P-NMR spectroscopy. Results show that the spectra of both the shed-vesicles and the sickle red cells are compatible with the occurrence of non-bilayer phases in the membrane bilayers. The findings support the concept that these membranes could contribute to the generation of antiphospholipid antibodies in sickle cell disease.

Anemia, Sickle Cell↗

PubMed1998

Nutritional and zinc status of head and neck cancer patients: an interpretive review.

In this review, we provide evidence based on our studies, for zinc deficiency and cell mediated immune disorders, and the effects of protein and zinc status on clinical morbidities in patients with head and neck cancer. We investigated subjects with newly diagnosed squamous cell carcinoma of the oral cavity, oropharynx, larynx, and hypopharynx. Patients with metastatic disease and with severe co-morbidity were excluded. Nutritional assessment included dietary history, body composition, and prognostic nutritional index (PNI) determination. Zinc status was determined by zinc assay in plasma, lymphocytes, and granulocytes. Pretreatment zinc status and nutritional status were correlated with clinical outcomes in 47 patients. Assessment of immune functions included production of TH1 and TH2 cytokines, T cell subpopulations and cutaneous delayed hypersensitivity reaction to common antigens. At baseline approximately 50% of our subjects were zinc-deficient based on cellular zinc criteria and had decreased production of TH1 cytokines but not TH2 cytokines, decreased NK cell lytic activity and decreased proportion of CD4+ CD45RA+ cells in the peripheral blood. The tumor size and overall stage of the disease correlated with baseline zinc status but not with PNI, alcohol intake, or smoking. Zinc deficiency was associated with increased unplanned hospitalizations. The disease-free interval was highest for the group which had both zinc sufficient and nutrition sufficient status. Zinc deficiency and cell mediated immune dysfunctions were frequently present in patients with head and neck cancer when seen initially. Zinc deficiency resulted in an imbalance of TH1 and TH2 functions. Zinc deficiency was associated with increased tumor size, overall stage of the cancer and increased unplanned hospitalizations. These observations have broad implications in the management of patients with head and neck cancer.

Carcinoma, Squamous Cell↗

PubMed1997

Digital ischemia and gangrene due to red blood cell aggregation induced by acquired dysfibrinogenemia.

Digital gangrene was observed in a patient who had angiographic findings of digital arterial occlusion. The patient's blood showed a marked red blood cell aggregation with rouleaux formation in long chains, which could not be dispersed at shear rates up to 200 sec-1. Studies of the patient's blood revealed the presence of an abnormal fibrinogen capable of aggregating normal red blood cells. This fibrinogen was found by Raman spectroscopy to have an increased alpha-helical content, whereas the beta-sheet content was decreased. Defibrinogenation therapy with ancrod resulted in a dramatic symptomatic relief. The disappearance of the abnormal fibrinogen 6 months later and an absence of a family history indicate that this dysfibrinogenemia was acquired.

Arterial Occlusive Diseases↗

PubMed1997

Paclitaxel, cisplatin, and 5-fluorouracil in patients with advanced or recurrent squamous cell carcinoma of the head and neck: a preliminary report.

The combination of 5-fluorouracil (5-FU) and cisplatin is considered the most active chemotherapy for patients with recurrent squamous cell carcinoma of the head and neck (SCCHN), with an overall response rate of 30%. Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has demonstrated activity in SCCHN and synergy with cisplatin. To augment the activity of the combination of 5-FU and cisplatin, a pilot study was designed to determine the feasibility of combining 3-hour infusional paclitaxel with 5-FU and cisplatin. To be eligible, patients had to have recurrent or advanced SCCHN with measurable or evaluable disease and no prior chemotherapy. A minimum of three courses had to be delivered to determine cumulative toxicity. The starting dose level consisted of paclitaxel 135 mg/m2 on day 1, cisplatin 75 mg/m2 on day 2, and 5-FU 1 g/m2 on days 2 through 6. The first treated patient developed grade 4 mucositis, which resulted in reducing dose level 1 of 5-FU to 800 mg/m2/d on days 2 through 6 (seven patients); subsequently, the 5-FU dose was adjusted to 1 g/m2/d on days 2 through 5 (nine patients). To date, 17 patients have been enrolled, with a median age of 62 years (range, 48 to 75 years). Of the 17 patients, nine had recurrent disease following prior surgery and/or radiotherapy and eight had previously untreated advanced SCCHN. Major toxicities were neutropenia and mucositis. There were four early deaths (two treatment-related and two cancer-related). Forty-seven courses of therapy were delivered, with a median of two (range, one to five). The overall response rate in 14 response-evaluable patients was 71% (10 of 14 patients; eight partial and two complete responses). Five of seven response-evaluable patients with recurrent disease had major responses (one complete and four partial responses). At the current dose, the combination of paclitaxel/5-FU/cisplatin is feasible and shows very encouraging activity, particularly in patients with recurrent SCCHN.

Aged↗

PubMed1996

Flow cytometric analysis of T and Tn epitopes on chronic lymphocytic leukemia cells.

Immunophenotyping of peripheral blood lymphocytes from six patients with B-cell chronic lymphocytic leukemia (B-CLL) and five normal volunteers was done and their T and Tn epitopes analyzed using specific monoclonal antibodies and flow cytometry. Lymphocytes from all patients showed strong Tn expression as compared to normal control lymphocytes. By contrast, T antigen was not expressed, The TN expression may be a useful diagnostic and prognostic marker for B-CLL.

Adult↗

PubMed1996

Reproducibility of erythrocyte polyamine measurements and correlation with plasma micronutrients in an antioxidant vitamin intervention study.

Erythrocyte polyamine measurements have been previously investigated as candidate biomarkers for hyperproliferation and recently as a potential intermediate endpoint in clinical chemoprevention trials with difluoromethylornithine, an inhibitor of polyamine biosynthesis. This study was performed to determine the reproducibility of erythrocyte polyamine measurements and their possible correlation with plasma micronutrients in seven healthy adults in an antioxidant vitamin intervention study. As part of this cross-over intervention study, three subjects took beta-carotene (31.4 mg/day) plus D-alpha-tocopherol acetate (720 IU/day) supplements during the first 3 months and four subjects took the supplements during the second 3 months. Heparinized blood samples were collected at baseline and every month over total 6 months for simultaneous determination of erythrocyte polyamines and plasma micronutrients by the high-performance liquid chromatographic method. For all the measures of erythrocyte polyamines the intraindividual variation was smaller than that between subjects, and three or four measurements required to accurately characterize long-term erythrocyte polyamines for an individual. The intra-class correlations were moderately high for all erythrocyte polyamine measurements, indicating a good reproducibility for intra-individual erythrocyte polyamine measurements. Based on monthly values, significant inverse correlations were found between erythrocyte spermidine and the plasma levels of retinol (r = -0.50) and lutein (r = -0.52). There were also significant inverse associations between erythrocyte spermine and plasma levels of alpha-tocopherol (r = -0.29), lutein (r = -0.44), lycopene (r = -0.29), beta-cryptoxanthin (r = -0.30), and total carotenoids (r = -0.29). The effects of supplementation upon the associations between erythrocyte polyamines and plasma nutrient levels were additionally addressed. The results indicate an acceptable longitudinal reproducibility of erythrocyte polyamine measurements, support the hypothesis that erythrocyte polyamine measurements may be correlated with plasma levels of certain nutrients, and suggest a further biomarker application in cancer prevention trials involving dietary modifications or specific relevant micronutrients.

Adult↗

PubMed1995

Real-time X-ray diffraction study at different scan rates of phase transitions for dipalmitoylphosphatidylcholine in KSCN.

Multibilayer arrays of dipalmitoylphosphatidylcholine (DPPC) in 1 M KSCN were characterized using real-time X-ray diffraction and differential scanning calorimetry. A phase transition sequence was observed as a function of increasing temperature which involved changes from the interdigitated subgel (Lc(inter)) to interdigitated gel (L beta(inter)) to disordered (L alpha) bilayer states. The phase transition mechanisms were unambiguously determined by comparison of results from fast and slow scans. The Lc(inter)-->L beta(inter) phase transition was shown to involve a continuous change in acyl chain spacing between the rectangular subgel acyl chain unit cell into an hexagonal gel acyl chain unit cell. The mechanism is similar to that for subgel to gel state transitions involving non-interdigitated DPPC bilayers.

1,2-Dipalmitoylphosphatidylcholine↗