Immunopharmacology of cancer vaccines: Restoration of NKG2D levels and functions in metastatic melanoma treated with exosomes

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Background: The C-type lectin-like stimulatory immune receptor Natural Killer group 2 receptor (NKG2D) is expressed by NK and CD8+ T cells. NKG2D engagement is a natural mediator of immunosurveillance which can be compromised by locally sustained ligand expression. In cancer patients with NKG2D ligand- expressing tumors, NK and CD8+ T cells often express low levels of NKG2D and are functionally compromised. Dentritic cell-derived-exosomes (Dex) are nanomeric vesicles harboring functional MHC/peptide complexes capable of promoting T cell immune responses and tumor rejection in mice. Two Dex Phase I trials highlighted the and the safety of exosome administration. The observation of clinical regressions in the absence of detectable T cell responses prompted the search for alternate effector mechanisms. We study NKG2D expression and NK cells function in peripheral lymphocytes before and after Dex therapy. Methods: Exosomes were purified from day 7 autologous monocyte derived-DC cultures. Fifteen patients were enrolled and received exosome vaccinations. NK cells functions prior or following exosome vaccines were tested in standard Na251CrO4 chromium release assays. NKG2D and NKG2D ligand expression were studied using flow cytometry and/or western blot experiments. Results: In sharp contrast with DC, Dex bear functional NKG2D ligands leading to a selective downregulation of NKG2D activating receptors on autologous NK cells in vitro. Long term administration of Dex could enhance NKG2D expression levels on NK and CD8+ T cells in 50% of patients, restoring killing of NKG2D ligand expressing K562 and autologous tumour. In contrast to NKG2D ligands shed by tumors mediating immunosuppressive activity, exosomal NKG2D ligands promote NKG2D-dependent effector functions in vivo, that might account for the non MHC restricted-antitumor effects observed in the trial. Conclusions: NK cell activation represent a new pharmacodynamic for Dex leading to tumor recognition and regression in vivo. The Phase II trial using Dex shall include the monitoring of NKG2D ligands on Dex preparation and follow up NKG2D levels, functions and polymorphism in patients.

No significant financial relationships to disclose.

Assessing rectal toxicity in a pilot study using intrarectal amifostine and concurrent radiation

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Background: There is evidence that daily intrarectal amifostine can protect rectal mucosa during prostate cancer treatment. Instruments more sensitive than the RTOG score may discriminate small but clinically important reductions in proctitis, however these tools need further evaluation. This study used both the RTOG GI toxicity score and expanded prostate cancer index composite (EPIC), a patient-administered quality of life instrument, to evaluate toxicity. Methods: In this pilot study, patients with localized prostate cancer were given daily amifostine (MedImmune, INC., Gaithersburg, MD) which was placed per rectum 30–45 min before 3D conformal radiation (66–76 Gy in 2 Gy fractions to a volume based on PSA, Gleason score and clinical stage). The first 18 patients enrolled received 1gram of amifostine and the next 12 patients were given 2 grams. Toxicity was assessed at baseline, 5, and 7 weeks during treatment and 3, 6, 12, 18, and 24 months after radiation and amifostine treatment. RTOG grading, an EPIC score and proctoscopic examination were done. The EPIC questionaire is a validated instrument that consists of 50 quality of life questions related to urinary, bowel, sexual and hormonal domains. Two subsets of the bowel domain were used: “bowel function” (BF) targets symptom severity and “bowel bother,” (BB) assesses quality of life subscales. Results: Previously reported results demonstrate a clear trend towards protection from rectal toxicity using 2 gm as compared to a 1 gm amifostine dose. Here, we report that the EPIC-BF and EPIC-BB scores are both highly correlated with the RTOG toxicity score with a pearsons coefficient of 0.98 and 0.97 respectively at a median follow up of 24 mos. There was no significant change in the RTOG GI toxicity score over the course of treatment for either amifostine dose group. There was a statistically significant decrease in EPIC-BF score at 7 weeks (p = 0.04) and the EPIC-BB score showed a trend toward improvement (p = 0.07) at the same time point. The EPIC scores at all other time points were not statistically different from baseline. Conclusions: The EPIC score may be a more sensitive measure to detect acute toxicity associated with prostate cancer treatment but needs further investigation in the acute setting.

No significant financial relationships to disclose.

Psychologic morbidities prior to loop electrosurgical excision procedure in the treatment of cervical intraepithelial neoplasia

The objective of this study was to assess and compare anxiety and distress in patients undergoing colposcopic examinations and loop electrosurgical excision procedure (LEEP). Patients seen for evaluation of cervical intraepithelial neoplasia (CIN) and LEEP were recruited. All patients received further teaching with respect to their abnormality right after the colposcopic evaluation by nursing staff. The Hospital anxiety and Depression Scale (HADS) and the Psychosocial Effects of Abnormal Pap Smears (PEAPS) questionnaires were used to measure and compare distress between the two groups. Linear regression models were built to identify significant predictive variables for psychologic morbidities. Twenty-one colposcopy and 20 LEEP patients participated in this study. No significant demographic differences were noted. Eighty-one percent of patients having colposcopy and 65% of those undergoing LEEP can be classified as having significant anxiety and depression based on the HADS questionnaire. Patients undergoing LEEP scored significantly better than colposcopy patients on the mean total PEAPS score and on the self-belief/cancer concern and effects on sexual relationship dimension scores. Significant psychologic morbidities exist in patients diagnosed with CIN. Face-to-face individualized education and support after colposcopy can decrease patients' distress at subsequent treatment visits.

Psychologic morbidities prior to loop electrosurgical excision procedure in the treatment of cervical intraepithelial neoplasia

The objective of this study was to assess and compare anxiety and distress in patients undergoing colposcopic examinations and loop electrosurgical excision procedure (LEEP). Patients seen for evaluation of cervical intraepithelial neoplasia (CIN) and LEEP were recruited. All patients received further teaching with respect to their abnormality right after the colposcopic evaluation by nursing staff. The Hospital anxiety and Depression Scale (HADS) and the Psychosocial Effects of Abnormal Pap Smears (PEAPS) questionnaires were used to measure and compare distress between the two groups. Linear regression models were built to identify significant predictive variables for psychologic morbidities. Twenty-one colposcopy and 20 LEEP patients participated in this study. No significant demographic differences were noted. Eighty-one percent of patients having colposcopy and 65% of those undergoing LEEP can be classified as having significant anxiety and depression based on the HADS questionnaire. Patients undergoing LEEP scored significantly better than colposcopy patients on the mean total PEAPS score and on the self-belief/cancer concern and effects on sexual relationship dimension scores. Significant psychologic morbidities exist in patients diagnosed with CIN. Face-to-face individualized education and support after colposcopy can decrease patients' distress at subsequent treatment visits.

French-Canadian linguistic validation of the NIH Chronic Prostatitis Symptom Index

INTRODUCTION

The NIH Chronic Prostatitis Symptom Index (CPSI) is recommended in the clinical evaluation of men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). However, its use is not possible in French speakers, as it has not been validated in this population. We performed a linguistic validation of the CPSI.

METHODS

Linguistic translation followed the forward-backward-forward technique and relied on professional medical translators, bilingual health professionals, and patient input. Along with the SF-12, the translated version was administered to a convenience sample of men presenting for pre-vasectomy visits (controls) and to consecutive patients with established CP/CPPS (cases). Men with CP/CPPS were subsequently asked to complete a 14-day retest questionnaire. Psychometric testing addressed standard reliability and validity characteristics.

RESULTS

Thirty-six cases and 38 controls with respective mean ages of 46.5 and 44.0 years participated and 33 (91.2%) cases completed the retest questionnaire. Pain (p<0.001), urinary (p<0.001) and quality-of-life (QOL) scale (p<0.001) score means differed between cases and controls. For the same scales, Cronbach's alphas for cases were respectively 0.70, 0.72 and 0.79 versus 0.80, 0.57, and 0.88 for controls. The retest product-moments were 0.83 for pain, 0.55 for urinary, and 0.83 for QOL scales. In cases, strong correlation was noted between QOL and pain scales (r=0.7), and between urinary and pain scales (r=0.6), versus moderate correlation between QOL and urinary scales (r=0.4). Negative correlation was recorded between CPSI scales and SF-12 scales, which ranged from -0.2 to -0.4.

CONCLUSIONS

When applied to CPPS and control subjects, the French Canadian CPSI translation demonstrates excellent discriminant properties. Moreover, its reliability and validity characteristics confirm the qualities of the CPSI as a standard evaluative tool for men with CPPS.

Human papilloma virus testing knowledge and attitudes among women attending colposcopy clinic with ASCUS/LGSIL pap smears

OBJECTIVE

To study women's knowledge regarding the role of human papilloma virus (HPV) in cervical intraepithelial neoplasia and their attitudes toward the integration of HPV testing as part of routine follow-up of atypical squamous cell of uncertain significance/low-grade squamous intraepithelial lesion (ASCUS/LGSIL) abnormalities.

METHODS

Over a 12-month period, all women attending the University of Ottawa colposcopy clinic for evaluation and follow-up of ASCUS/LGSIL Pap smears were recruited. Demographic data included age, nature of the Pap smear abnormality, gravidity, parity, occupation and education level, smoking history, previous history of abnormal smears, colposcopic examination and treatment, and current method of contraception. The women were asked to rate their level of concern over their Pap smear abnormality, from 0 (not concerned) to 10 (very concerned). Women's knowledge regarding the role of HPV in cervical intraepithelial neoplasia and the rationale behind the use of HPV testing was assessed by the clinic nurse as being minimal, moderate, or good, as defined by pre-specified criteria. Upon explanation by the nurses of the results of the recent ALTS (ASCUS/LGSIL Triage Study) trial, the women were asked to state whether they preferred to continue with regular colposcopic surveillance every 6 months, or to use the results of the HPV test, if negative, to reduce the number of colposcopy examinations to one annually. Descriptive statistics and logistic regression analysis were used to identify significant demographic factors associated with the women's preference for incorporation of HPV testing in their follow-up. All P values less than.10 were considered to be statistically significant, due to the exploratory nature of the study.

RESULTS

Of the 100 women who participated in the study, 42% presented with ASCUS. The mean age (+/- SD) of the women was 33.63 +/- 11.25 years (range, 18-75 years); 66% were office workers with at least a community college degree, 86% reported previous abnormal Pap smears, and 67% had previously been seen for colposcopy. Fifty-eight percent of the women rated their concern level as being 6 or more, while 15% ranked their concerns as maximal at 10. In terms of knowledge about HPV, 75% of the women had no or very minimal knowledge of the role of HPV in cervical intraepithelial neoplasia. With regard to HPV testing, 84% of the study group had either never heard of the test or had only a minimal knowledge of HPV testing. After being informed of the ALTS results, 64% of the women chose to use HPV testing to help in triaging the needs for frequent colposcopy. Logistic regression modelling showed that a college level education (odds ratio [OR], 2.27; 95% confidence interval [CI], 0.95-;5.45; P =.06) and history of previous treatment for abnormal Pap smears (OR, 3.31; CI, 0.88- 12.46; P =.07) were closely associated with the adoption of HPV testing in clinical management.

CONCLUSION

There exists a significant lack of knowledge about HPV and its role in the pathogenesis of cervical intraepithelial neoplasia. Women who have received previous treatments for cervical intraepithelial neoplasia and those with college-level educations were more likely to adopt this new technology as part of their care.

Spontaneous cardiomyocyte differentiation from adipose tissue stroma cells

Cardiomyocyte regeneration is limited in adult life. Thus, the identification of a putative source of cardiomyocyte progenitors is of great interest to provide a usable model in vitro and new perspective in regenerative therapy. As adipose tissues were recently demonstrated to contain pluripotent stem cells, the emergence of cardiomyocyte phenotype from adipose-derived cells was investigated. We demonstrated that rare beating cells with cardiomyocyte features could be identified after culture of adipose stroma cells without addition of 5-azacytidine. The cardiomyocyte phenotype was first identified by morphological observation, confirmed with expression of specific cardiac markers, immunocytochemistry staining, and ultrastructural analysis, revealing the presence of ventricle- and atrial-like cells. Electrophysiological studies performed on early culture revealed a pacemaker activity of the cells. Finally, functional studies showed that adrenergic agonist stimulated the beating rate whereas cholinergic agonist decreased it. Taken together, this study demonstrated that functional cardiomyocyte-like cells could be directly obtained from adipose tissue. According to the large amount of this tissue in adult mammal, it could represent a useful source of cardiomyocyte progenitors.

Metabolism of methoxymorpholino-doxorubicin in rat, dog and monkey liver microsomes: comparison with human microsomes

The morpholino anthracycline, methoxymorpholino-doxorubicin (MMDx) is a novel anticancer agent. The metabolism of this highly lipophilic doxorubicin analogue is not fully elucidated. MMDx is metabolically activated in vivo, resulting in an 80-fold increase in potency over the parent drug. In this study, MMDx in vitro metabolism was compared in rat, dog, monkey and human liver microsomes. When microsomal fractions were incubated with MMDx, 6-8 metabolites were formed depending on the species and on the substrate concentrations. Among these eight metabolites, three comigrated with authentic standards, namely MMDx-ol, PNU156686 and PNU159682, and the five others are in the process of being characterized. Quantitatively, monkey and human metabolize MMDx with a higher rate than rat and dog. Qualitatively, MMDx metabolic profile in dog microsomes was different from the three other species. MMDx-ol was predominant in dog and only minor in other species. In conclusion, MMDx metabolism was species-different. Rat and monkey liver microsomes may be used as models to study MMDx metabolism in humans. Dog liver microsomes may be a good model for studying the formation of MMDx-ol.

Determination of microcystins in blue-green algae, fish and water using liquid chromatography with ultraviolet detection after sample clean-up employing immunoaffinity chromatography

Anti-microcystin LR immunnoaffinity cartridges were evaluated for their ability to selectively remove microcystins from extracts of blue-green algae, fish and water samples for subsequent analysis by liquid chromatography with UV absorbance detection at 238 nm. Blue-green algae and fish samples were extracted with 75% methanol in water. A portion of the extract was diluted and passed through an immunoaffinity cartridge. Water samples were applied directly to the cartridge. The cartridge was rinsed with water and 25% methanol in water. The microcystins were eluted with 80% methanol in water containing 4% acetic acid. It was found that the cartridges were effective in isolating the microcystins from blue-green algae, fish and water samples, resulting in extracts that were clean enough to enable direct LC-UV detection down to approximately 0.03 microg/g in the blue-green algae and fish samples, and as low as 0.02 ng/ml for water samples. The cartridges were found to have a capacity of approximately 200 ng each for a mixture of microcystins RR, YR, LR and LA, or as much as 525-800 ng for individual compounds. Recoveries trough the complete analytical procedure ranged from 64 to 115% (all values) with an overall average of approximately 80% at spiking levels of 0.5-4.0 microg/g for the microcystins in blue-green algae. The average recoveries (n=8) from spiked (0.1-0.5 microg/g) fish samples were 73% for RR, 79% for YR, 81% for LR and 77% for LA, while from the spiked (2.0-0.04 ng/g) tap and river water samples (n=6), recoveries were 78% for RR, 86% for YR, 94% for LR and 89% for LA.

Comparison of liquid chromatography/mass spectrometry, ELISA, and phosphatase assay for the determination of microcystins in blue-green algae products

More than 100 samples of blue-green algae products (consisting of Aphanizomenon, Spirulina, and unidentified blue-green algae) in the form of pills, capsules, and powders were collected from retail outlets from across Canada. The samples were extracted with 75% methanol in water and centrifuged to remove solids. Aliquots of the extracts along with spiked blank sample extracts were sent to each participating laboratory and independently analyzed for microcystins by enzyme-linked immunosorbent assay (ELISA), protein phosphatase inhibition assay, and by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after sample cleanup using C18 solid-phase extraction. The results obtained by ELISA and LC-MS/MS agreed very well over a concentration range of about 0.5-35 microg/g. The colorimetric phosphatase results generally agreed with the other 2 methods. While the 2 biochemical assays measured total microcystin content compared with a standard of microcystin LR, the LC-MS/MS method measured specific microcystins (LA, LR, RR, YR) using external standards of these for identification and quantitation. Microcystin LR was found in all positive samples by LC-MS/MS. Microcystin LA was the only other microcystin found in the samples analyzed. These 2 microcystins represent essentially all the microcystins that were present in the extracts. Otherwise, the LC-MS/MS results would have been significantly lower than the results of the biochemical assays had other unknown microcystins been present.

Magnetic resonance spectroscopy of the malignant prostate gland after radiotherapy: a histopathologic study of diagnostic validity

PURPOSE

Accurate spatial representation of tumor clearance after conformal radiotherapy is an endpoint of clinical importance. Magnetic resonance spectroscopy (MRS) can diagnose malignancy in the untreated prostate gland through measurements of cellular metabolites. In this study we sought to describe spectral metabolic changes in prostatic tissue after radiotherapy and validate a multivariate analytic strategy (based on MRS) that could identify viable tumor.

METHODS AND MATERIALS

Transrectal ultrasound-guided prostate biopsies from 35 patients were obtained 18-36 months after external beam radiotherapy. One hundred sixteen tissue specimens were subjected to 1H MRS, submitted to histopathology, and analyzed for correlation with a multivariate strategy specifically developed for biomedical spectra.

RESULTS

The sensitivity and specificity of MRS in identifying a malignant biopsy were 88.9% and 92% respectively, with an overall classification accuracy of 91.4%. The diagnostic spectral regions identified by our algorithm included those due to choline, creatine, glutamine, and lipid. Citrate, an important discriminating resonance in the untreated prostate gland, was invisible in all spectra, regardless of histology.

CONCLUSIONS

Although the spectral features of prostate tissue markedly change after radiotherapy, MRS combined with multivariate methods of analysis can accurately identify histologically malignant biopsies. MRS shows promise as a modality that could integrate three-dimensional measures of tumor response.

Contractile behavior of smooth muscle actin-containing osteoblasts in collagen-GAG matrices in vitro: implant-related cell contraction

The contraction of connective tissue cells may facilitate their production and maintenance of extracellular matrix architecture and can benefit healing through wound closure. However, aberrant cell contraction can result in pathological contracture. Implants may stimulate this process leading to contracture of the surrounding fibrous capsule. In the case of compliant porous matrices used for tissue engineering the cell contraction may cause the constriction of pores and the distortion of the implant. The objective of this study was to determine if osteoblasts expressed a specific muscle actin, alpha-smooth muscle actin (SMA), that could provide for their contraction. Immunohistochemistry revealed the presence of SMA in some cells in all of three human and three canine trabecular bone specimens. The majority of the cells of an osteoblastic cell line, MC3T3-E 1, also expressed this actin isoform in two-dimensional culture and when seeded into a collagen-glycosaminoglycan (GAG) matrix. These SMA-containing cells were found to cause contraction of the collagen-GAG analog of extracellular matrix. These findings demonstrate that osteoblasts can display contractile behavior that might help to explain the mechanism by which they impart architecture to bone matrix, including that at implant interfaces. An understanding of this process could also guide the development of matrices for bone tissue engineering.

Induction and inhibition of cicletanine metabolism in cultured hepatocytes and liver microsomes from rats

Cicletanine, a racemic furopyridine derivative synthesized as racemate, is used as an antihypertensive agent. Its two enantiomers are involved in the pharmacological effects of the drug. Cicletanine is metabolized by conjugation enzyme systems (phase II) into sulfoconjugated or glucuroconjugated enantiomers. This study reports on the use of both the induction with 3-methylcholanthrene (3-MC) or phenobarbital (PB) and inhibition with selective compounds to determine and identify UGT isoenzymes involved in the metabolism of cicletanine enantiomers. PB and 3-MC both enhanced the cicletanine enantiomer glucuronidation. These two compounds being known as inducing agents of UGT2B1 and UGTIA6 isoforms, respectively, this suggests an implication of UGT2B1 and UGT1A6 isoforms in the metabolism of the two cicletanine enantiomers: ( + )-cicletanine and ( - )-cicletanine. The use of selective compounds for inhibition study evidenced, in addition to UGT2B1 and UGT1A6 isoforms, the involvement of other UGT isoforms such as UGT1A1, UGT2B7 and UGT2B15 in cicletanine metabolism.

Stereoselective biotransformation of cicletanine in cultured rat and human hepatocytes

Cicletanine [(+/-)-C] is a racemic furopyridine derivative used as an antihypertensive agent. Pharmacokinetic and metabolic studies have shown that cicletanine is rapidly and almost fully metabolized into sulfo- and glucuro-conjugated metabolites. However, the stereoselective metabolism of cicletanine is not well-known in humans. In the present study, the stereoselective aspect of cicletanine metabolism was investigated in cultured hepatocytes from humans and rats. The two enantiomers of cicletanine were both strongly metabolized in rat hepatocytes. So, after 24 h of incubation, very low amounts of free cicletanine were found [1.2% for (+)-C and 2.7% for (-)-C], respectively. In addition (+/-)-C was mainly biotransformed into conjugated metabolites: (-)-C mainly transformed into (-)-C-glucuronide (78.3+/-6.4%) and (+)-C mainly into (+)-C-sulfate (87.4+/-3.3%). In human hepatocytes, inter-individual variations were more marked than in rat hepatocytes. In addition (+/-)-C biotransformation in human was lower than the one observed in rat. (-)-C enantiomer was more metabolized than (+)-C. After a 24-h incubation the percentages of free (+)-C and (-)-C were 32.3+/-16.4 and 8.2+/-10.3, respectively. On the contrary to rat hepatocytes, both cicletanine enantiomers in humans were mainly metabolized into glucuroconjugated metabolites. These results clearly demonstrated that cicletanine underwent stereospecific metabolism in both rat and human hepatocytes.

Evaluation of silica- and sepharose-based immunoaffinity sorbents for sample cleanup in determination of fumonisins B1 and B2 in corn products

Anti-fumonisin B1 polyclonal antibodies were isolated from the serum of rabbits, immobilized onto the surface of glutaraldehyde-activated silica or Sepharose CL-4B particles, and placed into empty small plastic solid-phase extraction cartridges. The immobilized antibodies were evaluated for their ability to retain fumonisin B1 and fumonisin B2. Cartridge capacity and elution conditions were determined, and the results were compared to those obtained with a commercially available cartridge. The cartridges, which were tested for their effectiveness to isolate the fumonisins from extracts of corn flour and nacho chips, detected fumonisins down to levels of about 20 ng/g. However, additional cleanup was required for detection at lower concentrations. With the use of a strong anion-exchange cartridge as a preliminary cleanup before immunoaffinity chromatography, the detection limit reached 2-5 ng/g in the products tested. The silica sorbent material exhibited strong interactions with the fumonisins, requiring acidified ethanol-water mixtures for elution and resulting in an additional degree of selectivity in isolating fumonisins from sample extracts. The silica-based immunoaffinity cartridges were successfully reused more than 10 times; the Sepharose-based cartridges were less robust. Liquid chromatography with fluorescence detection was used after prechromatographic derivatization with o-phthaldialdehyde-mercaptoethanol.

Effects of oxazepam and acetaminophen on cicletanine metabolism in rat hepatocytes and liver microsomes

Cicletanine, a racemic furopyridine derivative synthesized as racemate, is used as an antihypertensive agent. Its two enantiomers are involved in the pharmacological effects of the drug. Cicletanine is metabolized by conjugation enzyme systems (phase II) into sulfoconjugated or glucuroconjugated enantiomers. As oxazepam and acetaminophen are widely prescribed, especially to elderly patients, these two drugs may be co-administered with cicletanine. The metabolic profile and the kinetics of biotransformation were studied by using rat hepatocytes and liver microsomes. Cicletanine was extensively metabolized by rat hepatocytes. More than 80% of the drug was biotransformed after a 3 h incubation. The formation of glucuroconjugated metabolites was characterized by the following kinetic parameters, i.e. Vmax = 2.05 +/- 0.21 nmol/min/mg protein and Km = 287 +/- 6.7 microM for (-)-cicletanine, and Vmax = 1.44 +/- 0.12 nmol/min/mg protein and K(m) = 171 +/- 4.1 microM for (+)-cicletanine. Oxazepam inhibited the glucuronidation of cicletanine in both rat hepatocytes and liver microsomes with a competitive-type inhibition, i.e. K(i) = 129 +/- 7.5 and 152 +/- 19.7 microM for (-)-cicletanine and (+)-cicletanine, respectively. The co-incubation of acetaminophen with cicletanine showed that only sulfoconjugation was inhibited in rat hepatocytes. Glucuronidation was not modified by acetaminophen. As natriuric activity is due to sulfoconjugated (+)-cicletanine, acetaminophen could potentially modulate in vivo the pharmacological effect of cicletanine. The data of the in vitro study reported here suggested an interaction between cicletanine and oxazepam or cicletanine and acetaminophen. However, the clinical impact of such a drug interaction needs further evaluation.

Suicide in the Northwest Territories: A descriptive review

The incidence of suicide among the populations of the Northwest Territories (NWT) is notably higher than in the rest of Canada. A comparison of three five-year time periods between 1982 and 1996 reveals an increasing incidence rate, particularly for Nunavat, the eastern half of the NWT, occupied primarily by Inuit people. This is largely attributable to a rising use of hanging as opposed to other methods of suicide. A coroner's record review of suicides occurring between 1994 and 1996 demonstrates the preponderance of young males and of Inuit among those who committed suicide, the majority of whom committed suicide in familiar settings, usually their own homes, and often while others were on the premises. Thirty-six percent of those who committed suicide had experienced a recent family or relationship breakup, and twenty-one percent were facing criminal proceedings. Understanding the impact of these and other reported circumstances on the imminent risk of suicide requires further investigation.

Neoplastic and nonneoplastic hepatic changes in lake whitefish (Coregonus clupeaformis) from the St. Lawrence River, Quebec, Canada

As part of a survey of fish diseases, lake whitefish (Coregonus clupeaformis) were collected in fall 1995 from the St. Lawrence River 15 km upstream of Quebec City, Quebec, Canada, to assess the prevalence of liver lesions. A total of 141 fish were captured and necropsied, and three standard sections of liver were taken for histological examination. Prevalences of altered hepatocyte foci, hepatocellular carcinoma, cholangioma, and cholangiocarcinoma were 0.7%, 2.1%, 0.7%, and 2.1%, respectively. Thus, the overall prevalence of liver neoplasia was 4.9% (7/141). Hepatic tumors were only observed in fish 7 years old or older. Fish age was significantly and positively correlated with the index assessing the number and size of macrophage aggregates (p<0.001; rs = 0.16). Hepatocyte vacuolation, anisokaryosis, lymphocytic infiltration, and bile duct hyperplasia were also observed but were not related to the age, length, sex, or condition factor of the fish. These results represent the first report on a series of hepatic tumors in a wild salmonid species.

Cell cycle dependent toxicity of an amphiphilic synthetic peptide

The cytotoxic properties of an amphiphilic synthetic peptide are presented. Comparative analysis of proliferating, differentiated and confluent H9C2 adherent cells and L1210 cells in suspension shows a correlation between toxicity and cell stage (proliferating cells). Electrophysiological measurements on Xenopus laevis oocytes bathed in the peptide also demonstrated the induction of cationic currents, which is voltage and phosphate dependent. These results allow us to hypothesize that the observed toxicity is related to membrane hyperpolarization of proliferating cells at the G1/S cell cycle phase transition.

Both cytochromes P450 2E1 and 3A are involved in the O-hydroxylation of p-nitrophenol, a catalytic activity known to be specific for P450 2E1

4-Nitrophenol 2-hydroxylation activity was previously shown to be mainly catalyzed by P450 2E1 in animal species and humans. As this chemical compound is widely used as an in vitro probe for P450 2E1, this study was carried out to test its catalytic specificity. First, experiments were carried out on liver microsomes and hepatocyte cultures of rat treated with different inducers. Liver microsomes from pyrazole- and dexamethasone-treated rats hydroxylated p-nitrophenol with a metabolic rate increased by 2.5- and 2.7-fold vs control. Dexamethasone treatment increased the hepatic content of P450 3A but not that of P450 2E1. Two specific inhibitors of P450 3A catalytic activities, namely, ketoconazole and troleandomycin (TAO), inhibited up to 50% of 4-nitrophenol hydroxylation in dexamethasone-treated rats but not in controls. Hepatocyte cultures from dexamethasone-treated rats transformed p-nitrophenol into 4-nitrocatechol 7.8 times more than controls. This catalytic activity was inhibited by TAO. Similarly, hepatocyte cultures from pyrazole-treated rats hydroxylated p-nitrophenol with a metabolic ratio increased by about 8-fold vs control. This reaction was inhibited by diethyl dithiocarbamate and dimethyl sulfoxide, both inhibitors of P450 2E1. Second, the capability of human P450s other than P450 2E1 to catalyze the formation of 4-nitrocatechol was examined in a panel of 13 human liver microsomes. Diethyl dithiocarbamate and ketoconazole reduced 4-nitrophenol hydroxylase activity by 77% (+/- 11) and 13% (+/- 16), respectively. Furthermore, the residual activity following diethyl dithiocarbamate inhibition was significantly correlated with seven P450 3A4 catalytic activities. Finally, the use of human cell lines genetically engineered for expression of human P450s demonstrated that P450 2E1 and 3A4 hydroxylated 4-nitrophenol with turnovers of 19.5 and 1.65 min-1, respectively. In conclusion, P450 3A may make a significant contribution to 4-nitrophenol hydroxylase activity in man and rat.

Comparison of three molecular typing methods in studies of transmission of Porphyromonas gingivalis

Porphyromonas gingivalis is associated strongly with severe periodontitis, but little information is available on possible transmission routes of this species. This study evaluated three DNA-based molecular typing methods for use in epidemiological surveys of P. gingivalis. In total, 32 isolates from eight married couples were investigated by: (i) restriction endonuclease analysis (REA) of whole chromosomal DNA; (ii) hybridisation of DNA fragments with ribosomal DNA (ribotyping); and (iii) amplification of DNA by the polymerase chain reaction with arbitrary primers (AP-PCR). The data obtained with the three methods were in broad agreement: in six of the eight couples, the isolates from husband and wife were indistinguishable, but isolates from unrelated individuals showed distinct types with all three methods. For some isolates, minor differences in REA pattern were obtained which could not be correlated with differences in ribotype or AP-PCR type. Ribotyping showed differences between isolates from one individual, which were indistinguishable with the other two methods. The patterns obtained with ribotyping or AP-PCR were simple in comparison to the relatively complex REA patterns. Although all three methods were concordant, AP-PCR was found to be the least time-consuming method. The data support the suggestion that P. gingivalis can be transmitted between spouses.

High alpha-linolenic acid flaxseed (Linum usitatissimum): some nutritional properties in humans

Although high alpha-linolenic acid flaxseed (Linum usitatissimum) is one of the richest dietary sources of alpha-linolenic acid and is also a good source of soluble fibre mucilage, it is relatively unstudied in human nutrition. Healthy female volunteers consumed 50 g ground, raw flaxseed/d for 4 weeks which provided 12-13% of energy intake (24-25 g/100 g total fat). Flaxseed raised alpha-linolenic acid and long-chain n-3 fatty acids in both plasma and erythrocyte lipids, as well as raising urinary thiocyanate excretion 2.2-fold. Flaxseed also lowered serum total cholesterol by 9% and low-density-lipoprotein-cholesterol by 18%. Changes in plasma alpha-linolenic acid were equivalent when 12 g alpha-linolenic acid/d was provided as raw flaxseed flour (50 g/d) or flaxseed oil (20 g/d) suggesting high bioavailability of alpha-linolenic acid from ground flaxseed. Test meals containing 50 g carbohydrate from flaxseed or 25 g flaxseed mucilage each significantly decreased postprandial blood glucose responses by 27%. Malondialdehyde levels in muffins containing 15 g flaxseed oil or flour/kg were similar to those in wheat-flour muffins. Cyanogenic glycosides (linamarin, linustatin, neolinustatin) were highest in extracted flaxseed mucilage but were not detected in baked muffins containing 150 g flaxseed/kg. We conclude that up to 50 g high-alpha-linolenic acid flaxseed/d is palatable, safe and may be nutritionally beneficial in humans by raising n-3 fatty acids in plasma and erythrocytes and by decreasing postprandial glucose responses.

Determinants of condom use among French heterosexuals with multiple partners

In September 1988, a sample of French individuals between 18 and 49 years of age, who reported more than one sexual partner in the past six months and who considered themselves heterosexuals (n = 1088), were interviewed at home about risk perception of human immunodeficiency virus (HIV) transmission, sexual behavior, and condom use. Systematic or occasional use of condoms during the previous 12 months was reported by 46.9 percent of respondents. Among condom users, 38.7 percent declared they had never used condoms before the last 12 months, fear of acquired immunodeficiency syndrome (AIDS) rather than contraception being the main motivation of these recent users. Multivariate analysis indicates that voluntary testing for HIV, average or more than average fear of sexually transmitted diseases (STDs), and knowledge of HIV carrier in personal relations are associated with condom use.

Studies on fibronectin in inflammatory vs non-inflammatory polymorphonuclear leucocytes of patients with rheumatoid arthritis. I. Immunofluorescent and flow cytometric analysis

Using indirect immunofluorescence and flow cytometry, we studied the reactivity of an antibody to human fibronectin with human polymorphonuclear leucocytes (PMNL). Our main objective was to compare the intensity of reaction of this antibody with inflammatory vs non-inflammatory PMNL. We used peripheral blood PMNL as a source of non-inflammatory cells and PMNL isolated from the synovial fluid of patients with rheumatoid arthritis as a source of inflammatory cells. Our findings revealed considerably brighter staining of the inflammatory PMNL. Using flow cytometry as a method of measurement, a difference in fluorescence intensity of at least 40 channels (log scale) was observed in all 12 patients studied when comparing peripheral blood with synovial fluid PMNL. In inflammatory PMNL, fibronectin was found both at the intracellular and membrane levels of the cell whereas fibronectin could be detected only intracellularly in non-inflammatory PMNL.

Studies on fibronectin in inflammatory vs non-inflammatory polymorphonuclear leucocytes of patients with rheumatoid arthritis. II. Synthesis and release of fibronectin in vitro

We conducted studies dealing with the synthesis and release of fibronectin in vitro by polymorphonuclear leucocytes (PMNL). The specific purpose of our study was to look for any changes in these events as they happen in inflammatory vs non-inflammatory PMNL. We used PMNL isolated from the synovial fluid of patients with rheumatoid arthritis as a source of inflammatory cells and PMNL isolated from peripheral blood as a source of non-inflammatory cells. Marked differences were observed. Using 35S-methionine metabolic labelling and SDS-polyacrylamide gel analysis, we were first able to clearly observe an increased synthesis of fibronectin by inflammatory PMNL when compared to non-inflammatory PMNL. Furthermore, the release of fibronectin in vitro by these cells was increased by factors of up to 20 when compared to non-inflammatory peripheral blood PMNL. Experimental evidence was also obtained which strongly suggests that fibronectin exists in a stored form inside the inflammatory PMNL we used in this study. Finally, we observed that PMNL are capable of synthesizing a 95 kD gelatin binding protein which appears to be distinct from fibronectin.