Liver lipid metabolism

The liver plays a key role in lipid metabolism. Depending on species it is, more or less, the hub of fatty acid synthesis and lipid circulation through lipoprotein synthesis. Eventually the accumulation of lipid droplets into the hepatocytes results in hepatic steatosis, which may develop as a consequence of multiple dysfunctions such as alterations in beta-oxidation, very low density lipoprotein secretion, and pathways involved in the synthesis of fatty acids. In addition an increased circulating pool of non-esterified fatty acid may also to be a major determinant in the pathogenesis fatty liver disease. This review also focuses on transcription factors such as sterol-regulatory-element-binding protein-1c and peroxisome proliferator-activated receptor alpha, which promote either hepatic fatty acid synthesis or oxidation.

Prevalence of M. tuberculosis infection and tuberculosis disease among HIV-infected people in Spain

OBJECTIVE

To study the prevalence of Mycobacterium tuberculosis infection (MTBI) and past/current tuberculosis (TB) among human immunodeficiency virus (HIV) infected persons in Spain.

DESIGN

Longitudinal study conducted between 2000 and 2003 at 10 HIV hospital-based clinics. Data were drawn from clinical records. Associations were measured using odds ratios (ORs) and their 95% confidence intervals (95%CI).

RESULTS

Of the 1242 persons who met the eligibility criteria, most were male (75%), aged <40 years (75%) and unemployed (40%). HIV infection occurred through intravenous drug use (53%), heterosexual sex (29%) and sex between men (16%). In the initial evaluation, 315 subjects had evidence of MTBI: 84 (6.8%) had a history of TB, 23 (1.8%) current TB and 208 (16.8%) latent tuberculosis infection (LTBI). MTBI was associated with male sex, age 30-49 years, contact with a TB case, homelessness, poor education, and negatively with CD4 <100 cells/mm(3). Among subjects with MTBI, past/current TB was associated with retirement/disability (OR 6, 95%CI 1.6-22.5), CD4 <200 cells/mm(3) (OR 9.7, 95%CI 3.8-24.6), viral load >55,000 copies (OR 5.3, 95%CI 1.4-20.0), and negatively, with skilled work (OR 0.4, 95%CI 0.1-1.0) or administrative/managerial/professional work (OR 0.05, 95%CI 0.01-0.4).

CONCLUSION

Social context has an impact on the effectiveness of HIV and TB control programmes even in industrialised countries with free access to health care.

Usefulness of PCR strategies for early diagnosis of Chagas' disease reactivation and treatment follow-up in heart transplantation

Heart transplantation (HTx) is a useful therapy for end-stage Chagaś cardiomyopathy; however, Chagas reactivation remains a mayor complication. Parasitological methods offer poor diagnostic sensitivity, and use of more sensitive tools such as the Polymerase chain reaction (PCR) is usually necessary. In the present study, reactivation incidence and PCR usefulness for early reactivation diagnosis, as well as for treatment response evaluation during follow-up, were analyzed using Strout parasite detection test, in 10 of 222 consecutive HTx patients suffering Chagas cardiomyopathy. PCR strategies targeted to minicircle sequences (kDNA, detection limit 1 parasite/ 10 mL blood) and miniexon genes (SL-DNA, 200 parasite/10 mL) were performed to compare parasite burdens between samples. No patients received prophylactic antiprotozoal therapy (benznidazole). Five patients (50%) exhibited clinical reactivation within a mean period of 71.6 days; positive Strout results were observed in most cases presenting clinical manifestations. kDNA-PCR was positive 38-85 days before reactivation, whereas SLDNA-PCR became positive only 7-21 days later, revealing post-HTx parasitic load enhancement present prior to clinical reactivation development. Reactivations were successfully treated with benznidazole and generated negative PCR results. Results observed in this study indicate the value of PCR testing for an early diagnosis of Chagas reactivation as well as for monitoring treatment efficacy.

Analysis of 4495 canine and feline uroliths in the Benelux. A retrospective study: 1994?2004

From 1994 to 2004, Hill's Pet Nutrition received 4495 canine (65%) and feline (35%) uroliths from Benelux veterinary practitioners. They were sent to the Minnesota Urolith Center, USA for analysis. In 1994, 110 uroliths were analysed - 85% from dogs - and in 2003, 1067 uroliths were analysed - 59% from dogs. During this period, substantial changes were observed in composition. In 1994, 77% of the cats had uroliths composed of struvite, and 12% had uroliths composed of calcium oxalate. In 2003, feline uroliths were composed of 32% struvite, and 61% calcium oxalate. The same evolution was observed in the dogs. In 1994, 51% of canine uroliths were composed of struvite, and 33% of calcium oxalate. In 2003, 40% had struvite uroliths, and 46% had calcium oxalate uroliths. A significant effect of the size, the breed, and the gender were noticed in the dogs. The mean age of uroliths appearance was 7.3 years in the dogs and 7.2 years in the cats. The findings are similar to those previously published in the USA.

Endocrine, liver-derived IGF-I is of importance for spatial learning and memory in old mice

IGF-I is a neuroprotective hormone, and neurodegenerative disorders, including Alzheimer's disease, have been associated with decreased serum IGF-I concentration. In this study, IGF-I production was inactivated in the liver of adult mice (LI-IGF-I(-/-)), resulting in an approximately 80-85% reduction of circulating IGF-I concentrations. In young (6-month-old) mice there was no difference between the LI-IGF-I(-/-) and the control mice in spatial learning and memory as measured using the Morris water maze test. In old (aged 15 and 18 months) LI-IGF-I(-/-) mice, however, the acquisition of the spatial task was slower than in the controls. Furthermore, impaired spatial working as well as reference memory was observed in the old LI-IGF(-/-) mice. Histochemical analyses revealed an increase in dynorphin and enkephalin immunoreactivities but decreased mRNA levels in the hippocampus of old LI-IGF-I(-/-) mice. These mice also displayed astrocytosis and increased metabotropic glutamate receptor 7a-immunoreactivity. These neurochemical disturbances suggest synaptic dysfunction and early neurodegeneration in old LI-IGF-I(-/-) mice. The decline in serum IGF-I with increasing age may therefore be important for the age-related decline in memory function.

Effect of ovariectomy and ad libitum feeding on body composition, thyroid status, ghrelin and leptin plasma concentrations in female dogs*

The objective of this study was to evaluate the effects of ovariectomy (i) and ad libitum feeding (ii) on energy intake, body weight (BW), body composition, thyroid status, leptin and ghrelin plasma concentrations. Four young adult female Beagle dogs were fed a maintenance diet for 6 weeks prior to ovariectomy, then 6 months after. Food allowance was adjusted in order to maintain optimal BW. Then, a diet slightly higher in energy concentration was fed ad libitum for 4 months. The maintenance diet was then fed ad libitum for one additional month. The maintenance of optimal BW after ovariectomy required a significant decrease in energy allowance. No increase in fat mass was observed. Ghrelin concentration remained unchanged. During the first month of ad libitum feeding, plasma ghrelin concentration and energy intake increased, then they decreased. Mean BW, plasma leptin, thyrotropin (TSH), total triiodothyronine (TT3) and total thyroxine (TT4) concentrations significantly increased over the study. The BW increase was exclusively due to an increase in body fat. In conclusion, energy allowance should be strictly controlled in spayed female dogs. The results suggest that in dogs, thyroid hormones, leptin and ghrelin concentrations change in response to a positive energy balance in an attempt to limit weight gain. However, the significant weight gain shows that this goal was not achieved.

Binding of single nucleotides to H+-ATP synthases observed by fluorescence resonance energy transfer

F(0)F(1)-ATP synthases couple proton translocation with the synthesis of ATP from ADP and phosphate. The enzyme has three catalytic nucleotide binding sites, one on each beta-subunit; three non-catalytic binding sites are located mainly on each alpha-subunit. In order to observe substrate binding to the enzyme, the H(+)-ATP synthase from Escherichia coli was labelled selectively with the fluorescence donor tetramethylrhodamine (TMR) at position T106C of the gamma-subunit. The labelled enzymes were incorporated into liposomes and catalysed proton-driven ATP synthesis. The substrate ATP-Alexa Fluor 647 was used as the fluorescence acceptor to perform intermolecular fluorescence resonance energy transfer (FRET). Single molecules are detected with a confocal set-up. When one ATP-Alexa Fluor 647 binds to the enzyme, FRET can be observed. Five stable states with different intermolecular FRET efficiencies were distinguished for enzyme-bound ATP-Alexa Fluor 647 indicating binding to different binding sites. Consecutive hydrolysis of excess ATP resulted in stepwise changes of the FRET efficiency. Thereby, gamma-subunit movement during catalysis was directly monitored with respect to the binding site with bound ATP-Alexa Fluor 647.

Orthotopic heart transplantation in elderly patients: A 10-year experience at a single center

INTRODUCTION

A consensus has not yet been reached regarding the indications for orthotopic heart transplantation (OHT) in elderly patients or the age limit contraindicating the procedure. The objective of this study was to assess OHT outcomes to determine whether elderly patients benefit from the procedure.

METHODS

From February 1993 to February 2003, 178 OHTs were performed on recipients of mean age 47.4 +/- 15 years (range, 4 to 74) including 80.3% men. The population was divided into two groups: group A included patients >/= 60 years, and group B those younger than that age. Survival was analyzed for the overall population and for both age groups during a 10-year follow-up period.

RESULTS

Group A included 36 patients (20.8%) and group B 142 patients (79.2%). Mean age was 63.7 +/- 2.9 years (60 to 74) in A, and 43 +/- 13.9 years (4 to 59) in B. In-hospital mortality was significantly higher among group A (n = 11, 31.4%) compared to B (n = 17, 12.1%, P =.008). Survival at 1, 5, and 10 years was 61.5% +/- 8%, 58.1% +/- 8.3%, and 49.8% +/- 10.5% group A; and 84.2% +/- 3%, 73.7% +/- 4.1%, and 69.9% +/- 4.7 for group B. Elderly patients showed a lower survival rate (49.8%) compared with the younger group (69.9%) at 10-year follow-up (P =.007). Conditional survival at 9 years failed to show significant differences (A 72.2% vs B 79.6%, P =.4).

CONCLUSION

In our population, elderly recipients showed a higher in-hospital mortality. However, when the first post-OHT year was excluded, we found similar survival rates for both age groups.

Hypercholesterolaemia in a family of rough collie dogs

A family of five privately owned rough collie dogs was referred for corneal lipidosis and also suffered from hypercholesterolaemia. The hypercholesterolaemia was characterised by an increase in the alpha-2 high density lipoprotein-1 band and was due to an increase in the cholesterol content of the very low density lipoprotein, low density lipoprotein and possibly the high density lipoprotein-1 fractions. A low-fat and energy-restricted diet did not reduce either total cholesterol or the corneal lipidosis. Corneal lipidosis regressed with short-chain fructo-oligosaccharide supplementation. However, the effects of short-chain fructo-oligosaccharides on total cholesterol were transient and variable.

Evolution of blood parameters during weight loss in experimental obese Beagle dogs

The effects of weight loss on hormonal and biochemical blood parameters were measured monthly [carnitine, creatinine, urea, free T4 (fT4), total T4 (TT4), plasma alkaline phosphatases (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), potassium and total proteins] or bimonthly [cholesterol, triglycerides, non-esterified fatty acids (NEFA), insulin-like growth factor I (IGF-I), glucose, insulin] in eight obese Beagles dogs fed either a high protein dry diet, DP (crude protein 47.5%, on dry matter basis) or a commercial high fibre diet, HF (crude protein 23.8%, crude fibre 23.3%). The dogs were allotted to two groups according to sex and body weight (BW) and they were respectively fed with the DP or the control HF diet during 12-26 weeks, until they reach their optimal BW. The plasma basal triglycerides and cholesterol concentrations were decreased by the two diets but the difference was only significant for the DP diet. The plasma mean NEFA concentration increased regularly over the period with the HF diet, without significant difference between the two diets. No effect of diet or weight loss was observed on plasma carnitine, urea, creatinine, ALP, AST, ALT, potassium, TT4, FT4, IGF-I, glucose and insulin. Weight loss induced a decrease in fT4 plasma concentration (p < 0.001). The high protein diet allowed a safe weight loss.

Ad libitum feeding following ovariectomy in female Beagle dogs: effect on maintenance energy requirement and on blood metabolites

The aim of this study was (i) to evaluate the effect of ovariectomy on daily energy requirement in Beagle dogs, and (ii) to evaluate the effects of ad libitum feeding with a high energy diet on energy consumption, body weight gain and blood metabolites in these spayed dogs. Four young adult female Beagle dogs were used. Ovariectomy induced a significant decrease of daily energy requirement in dogs. Ad libitum feeding, initiated 6 months after spaying, induced a significant increase in consumption in spayed dogs. This overconsumption was greatest during the first month of ad libitum feeding but continued for the entire 4 months of this period. When fed ad libitum, dogs gained excess body weight without significant effect on plasma cholesterol, triglycerides, glucose and insulin, at short term. These data suggest that energy intake should be strictly controlled to avoid excess weight gain in spayed dogs.

Clinical value of CEA and CA125 regarding relapse and metastasis in resectable non-small cell lung cancer

BACKGROUND

The aim of the present study was to evaluate the value of serum Carcinoembryonic Antigen (CEA) and CA125 antigen assay for monitoring the activity of non-small cell lung cancer (NSCLC) after curative surgical resection.

PATIENTS AND METHODS

Serum CEA and CA 125 were determined preoperatively and at every postoperative visit, in 113 patients with NSCLC (TNM stages I, II, IIIA). Both markers were assayed by magnetic particle enzyme immunoassay.

RESULTS

Tumor recurrence was more frequent in patients with preoperative CA 125 levels above the cut-off (15 U/ml) (28 out of 47) (59.5%) than in those with low values (18 out of 66) (27.2%) (p < 0.001). The 36-month disease-free survival was lower for patients with elevated CA 125 (37%) than among those with low levels (72%) (p = 0.006). High CA 125 was an independent predictor of the risk of postoperative recurrence (Hazard Ratio: 3.02)(95% CI: 1.41-6.49). No relationship was detected between preoperative serum CEA and risk of recurrence. High preoperative CA125 indicated elevated risk for disseminated recurrence (Hazard Ratio: 7) (95% CI: 2.39-20.51), but not for locoregional failure. No significance was detected for CEA, either in locoregional or disseminated recurrence. Forty-six subjects (40.7%) developed tumor recurrence. At the diagnosis of relapse, serum CEA was elevated in 16 patients (34.7%) and CA125 in 26 (56.5%). Sensitivity was higher in the case of disseminated recurrence (63% for CA125 and 43.3% for CEA) and decreased in locoregional relapse (43.7% for CA125 and 18.7% for CEA). The specificity was 97% for CEA and 59% for CA125.

CONCLUSION

Serum CA125 is a useful prognostic marker in NSCLC. The predictive information is especially useful to estimate the risk of disseminated recurrence. Serial determinations of CEA and CA125 during the postoperative follow-up do not show enough sensitivity/specificity to recommend their use for diagnosis of tumor relapse.

Evaluation of thyroid function in obese dogs and in dogs undergoing a weight loss protocol

Obesity and weight loss have been shown to alter thyroid hormone homeostasis in humans. In dogs, obesity is the most common nutritional problem encountered and weight loss is the cornerstone of its treatment. Therefore, it is important to clarify how obesity and weight loss can affect thyroid function test results in that species. The objectives of this study were to compare thyroid function in obese dogs and in lean dogs and to explore the effects of caloric restriction and weight loss on thyroid hormone serum concentrations in obese dogs. In the first experiment, 12 healthy lean beagles and 12 obese beagles were compared. Thyroid function was evaluated by measuring serum concentrations of total thyroxine (TT4), free thyroxine (FT4), total triiodothyronine (TT3), thyrotropin (TSH), and reverse triiodothyronine (rT3) as well as a TSH stimulation test using 75 microg i.v. of recombinant human TSH. In the second experiment, eight obese beagles were fed an energy-restricted diet [average 63% maintenance energy requirement (MER)] until optimal weight was obtained. Blood samples for determination of TT4, FT4, TT3, TSH and rT3, were taken at the start and then weekly during weight loss. Only TT3 and TT4 serum concentrations were significantly higher in obese dogs as compared to lean dogs. In the second experiment, weight loss resulted in a significant decrease in TT3 and TSH serum concentrations. Thus obesity and energy restriction significantly alter thyroid homeostasis in dogs, but the observed changes are unlikely to affect interpretation of thyroid function test results in clinics.

Tuberculosis in Spain: epidemiological pattern and clinical practice

SETTING

Thirteen Autonomous Regions in Spain.

OBJECTIVE

To study the incidence of all forms of tuberculosis (TB) and investigate clinical practice in TB.

DESIGN

Cases of all forms of tuberculosis diagnosed in the study setting from May 1986 to April 1997 were identified though active search of different databases. Clinical and epidemiological information on cases was collected from clinical records or by interview with physicians.

RESULTS

The overall incidence of all forms of tuberculosis was 38.5/100,000 and the incidence of smear-positive disease was 13.83/100,000. Most cases (97.1%) were Spanish nationals, with rates higher in men than in women (52.7/100,000 vs. 24.87/100,000) and in groups aged 25-34 and 75 years and over (61.35/100,000 and 59.35/100,000, respectively). Disseminated forms were frequent (6.6%), and the most common risk factor was human immunodeficiency virus (HIV) infection (17.7% of cases). Hospitalisation was common (71.6%). Microbiological confirmation of diagnosis was sought for 87.7% of the cases (91.8% of pulmonary vs. 75.5% of extra-pulmonary cases), and 65.2% were culture-positive (73.8% of pulmonary vs. 39.7% of extra-pulmonary cases). HIV-infected patients were treated in almost equal proportions with three or four drugs (49.7% and 48.2%, respectively), while HIV-negative cases or those whose HIV status was unknown were usually treated with three drugs.

CONCLUSION

The epidemiological pattern of TB in Spain is different to other industrialised countries in the age distribution of cases and the proportions of foreigners and cases with HIV infection. Microbiological confirmation of diagnosis is more common in pulmonary than in extra-pulmonary disease, and treatment with four drugs more frequent in HIV-positive cases.

Decreased MK-801 binding in discrete hippocampal regions of prion-infected mice

The neurochemical alterations associated with neurodegeneration in prion diseases are not well defined. It is therefore of interest to study the influence of prion infection on messenger molecules and their receptors. In the present study we have analyzed the possible involvement of NMDA receptors in prion-infected mice using ligand binding autoradiography and iodinated MK-801, a noncompetitive NMDA antagonist. The results show a reduced binding of MK-801 in discrete regions of hippocampus at 110 days after infection, that is before the appearance of behavioral symptoms. In addition, early transient increases in MK-801 binding were observed in several layers. The exact neuroanatomical correlate of these changes in MK-801 binding, as well as its functional significance in relation to prion symptomatology, remain to be analyzed.

Prediction of protein digestibility in dog food by a multi-enzymatic method: a useful technique to develop

The multi-enzymatic method with constant pH described by Dufour-Etienne et al. (Rec. Méd. Vét. 168, 789-796, 1992) was tested using 17 industrial dry dog foods and two ingredients, sodium caseinate and beef meat, which were used as references. The quantity of sodium hydroxide added to the enzymatic solution was measured after incubation times of 2, 5 and 10 min and the best prediction of the apparent protein digestibility was obtained with an incubation time fixed at 2 min. The volume of sodium hydroxide 0.1 N constantly added to maintain the pH of the solution at 8 was correlated to the value of in vivo digestibility of the protein measured in the dog. The correlation coefficient obtained was 0.90 with a standard error of the regression of 1.9 for all samples. The correlation coefficients calculated for incubation times of 5 and 10 min were lower than that at 2 min; thus an incubation period of 2 min provided the highest correlation coefficient for this multi-enzymatic method at constant pH. However, considering the lack of samples with an apparent protein digestibility ranging between 85 and 95%, the slope of the regression line and the correlation coefficient were strongly influenced by the ingredients, such that when the correlation coefficient was calculated for 17 dog foods without the reference ingredients, a coefficient of 0.71 (+/- 1.9) was obtained. These tests of in vitro digestibility are valuable to predict the apparent digestibility of the protein in the dog, but, it is essential to confirm the results by an in vivo test.

Subcortical anarthria: a case report

A 56-year-old right-handed male with a history of hypertension and diabetes presented two episodes of stroke: The first affected territory was the left anterior coroidal artery (capsular and paracapsular infarcts at the level of the genu and posterior arm of the internal capsule) and the second was the right thalamus, due to a hematoma. Following the first stroke, the patient developed severe dysarthria and after the second stroke remained anarthric. The pathophysiology of the disorder is discussed, and the role of the left and right thalamus as far as speech is concerned is reviewed.

Neuropeptides in hippocampus and cortex in transgenic mice overexpressing V717F beta-amyloid precursor protein--initial observations

Immunohistochemistry was used to analyse 18- and 26-month-old transgenic mice overexpressing the human beta-amyloid precursor protein under the platelet-derived growth factor-beta promoter with regard to presence and distribution of neuropeptides. In addition, antisera/antibodies to tyrosine hydroxylase, acetylcholinesterase, amyloid peptide, glial fibrillary acidic protein and microglial marker OX42 were used. These mice have been reported to exhibit extensive amyloid plaques in the hippocampus and cortex [Masliah et al. (1996) J. Neurosci. 16, 5795-5811]. The most pronounced changes were related to neuropeptides, whereas differences between wild-type and transgenic mice were less prominent with regard to tyrosine hydroxylase and acetylcholinesterase. The main findings were of two types; (i) involvement of peptide-containing neurites in amyloid beta-peptide positive plaques, and (ii) more generalized changes in peptide levels in specific layers, neuron populations and/or subregions in the hippocampal formation and ventral cortices. In contrast, the parietal and auditory cortices were comparatively less affected. The peptide immunoreactivities most strongly involved, both in plaques and in the generalized changes, were galanin, neuropeptide Y, cholecystokinin and enkephalin. This study shows that there is considerable variation both with regard to plaque load and peptide expression even among homozygotes of the same age. The most pronounced changes, predominantly increased peptide levels, were observed in two 26-month-old homozygous mice, for example, galanin-, enkephalin- and cholecystokinin-like immunoreactivities in stratum lacunosum moleculare, and galanin, neuropeptide Y, enkephalin and dynorphin in mossy fibers. Many peptides also showed elevated levels in the ventral cortices. However, decreases were also observed. Thus, galanin-like immunoreactivity could not any longer be detected in the diffusely distributed (presumably noradrenergic) fiber network in all hippocampal and cortical layers, and dynorphin-like immunoreactivity was decreased in stratum moleculare, cholecystokinin-like immunoreactivity in mossy fibers and substance P-like immunoreactivity in fibers around granule cells. The significance of generalized peptide changes is at present unclear. For example, the increase in the mainly inhibitory peptides galanin, neuropeptide Y, enkephalin and dynorphin and the decrease in the mainly excitatory peptide cholecystokinin in mossy fibers (and of substance P fibers around granule cells) indicate a shift in balance towards inhibition of the input to the CA3 pyramidal cell layer. Moreover, it may be speculated that the increase in levels of some of the peptides represents a reaction to nerve injury with the aim to counteract, in different ways, the consequences of injury, for example by exerting trophic actions. Further studies will be needed to establish to what extent these changes are typical for Alzheimer mouse models in general or are associated with the V717F mutation and/or the platelet-derived growth factor-beta promoter.

Determination of free and total sulfate and phosphate in glycosaminoglycans by column-switching high-performance size-exclusion and ion chromatography and single-column ion chromatography

Analytical procedures for the determination of free and total sulfate and phosphate in glycosaminoglycans by high-performance liquid chromatography were studied. A column-switching method coupling high-performance size-exclusion chromatography (HPSEC) and ion chromatography (IC) is proposed for the determination of free anions. Good run-to-run and day-to-day precision values (RSD) of < 4.7% were obtained for both anions. Total anion contents were determined after wet acid hydrolysis with nitric acid-hydrogen peroxide (5 + 1) by single-column IC and ICP-AES elemental analysis in order to validate the results. Recoveries ranging from 94.6 to 99.0% for sulfate and from 80.8 to 94.0% for phosphate were obtained. Both HPSEC-IC and single-column IC methods were applied to the analysis of a low molecular mass heparin, a non-fractionated heparin and a chondroitin 4-sulfate. From the free and total sulfate determinations, the content of linked sulfur was calculated and ranged from 5.1 to 12.2% m/m.

Micronucleus formation in human lymphocytes and in the metabolically competent human hepatoma cell line Hep-G2: results with 15 naturally occurring substances

To examine the concordance of two metabolizing systems for use in genotoxocity testing with the micronucleus test, 15 naturally occurring substances (arecoline, the plant extract aristolochic acid, beta-asarone, benzyl acetate, coumarin, emodine, isatidine dihydrate, monocrotaline, psoralen, reserpine, retrorsine, safrole, sanguinarine chloride, tannin and thiourea) were tested for their genotoxicity in the cytokinesis-block micronucleus test in vitro with human lymphocytes and in the presence and the absence of an exogenous metabolizing system from rat liver S9-mix and the metabolically competent human hepatoma cell line Hep-G2. Arecoline, the plant extract aristolochic acid, psoralen and tannin caused a significant increase in the number of micronuclei in human lymphocytes in the presence and the absence of an exogenous metabolising system from rat liver S9-mix and the metabolically competent human hepatoma cell line Hep-G2. A significant increase in the number of micronuclei with beta-asarone, coumarin, monocrotaline and retrorsine could be detected in the presence of S9-mix and the cell line Hep-G2. Benzyl acetate, emodine, isatidine dihydrate, reserpine, safrole, sanguinarine chloride and thiourea did not reveal any micronucleus inducing activity in either human lymphocytes or in Hep-G2. In addition to the other Hep-G2 results in the literature, this human hepatoma cell line could have a useful potential in the in vitro micronucleus test.

Influence of tumor localization on the prognostic value of P53 protein in colorectal adenocarcinomas

BACKGROUND

The prevalence of genetic alterations is different in primary carcinomas from the proximal colon when compared with carcinomas from the distal colorectum. The objective of this work was to explore the existence of possible differences in the informative weight of the risk of tumor recurrence provided by p53 immunostaining depending on the localization of the neoplasm.

PATIENTS AND METHODS

Nuclear immunohistochemical expression of p53 protein was determined in formalin-fixed paraffin-embedded archival tumor tissue samples from 190 primary colorectal adenocarcinomas. The relative prognostic importance on the risk of recurrence of each variable was assessed in a Cox's proportional hazard regression analysis. Multiplicative interaction terms between p53 and tumor site were included in the multivariate models in order to test their joint effect on survival.

RESULTS

One hundred and one patients (53.1%) manifested nuclear accumulation of the protein. P53 overexpression was more frequent in distal than in proximal tumors (58.5% ve s 41.7%) (p = 0.03). Disease-free survival was lower in p53-positive cases (75% versus 38%) (p = 0.006), but significance of the association varied according to the localization of the tumor (p = 0.004 in proximal carcinomas and p = 0.049 in distal carcinomas). Multivariate analysis identified p53 positivity and distal tumor localization as the factors significantly associated with a high risk of recurrence Interaction between p53 expression and localization was present. P53 exhibited different prognostic value in distal and proximal colon. While adjusted hazard ratio for positive p53 was 1.99 in distal cancers, it was 8.04 for proximal tumors.

CONCLUSION

The prognostic with value of tumor recurrence associated overexpression of p53 protein is influenced by the location of the tumor. The negative predictive weight is significantly higher in proximal than in distal cancers.

Neuropeptides--an overview

The present article provides a brief overview of various aspects on neuropeptides, emphasizing their multitude and their wide distribution in both the peripheral and central nervous system. Interestingly, neuropeptides are also expressed in various types of glial cells under normal and experimental conditions. The recent identification of, often multiple, receptor subtypes for each peptide, as well as the development of peptide antagonists, have provided an experimental framework to explore functional roles of neuropeptides. A characteristic of neuropeptides is the plasticity in their expression, reflecting the fact that release has to be compensated by de novo synthesis at the cell body level. In several systems peptides can be expressed at very low levels normally but are upregulated in response to, for example, nerve injury. The fact that neuropeptides virtually always coexist with one or more classic transmitters suggests that they are involved in modulatory processes and probably in many other types of functions, for example exerting trophic effects. Recent studies employing transgene technology have provided some information on their functional role, although compensatory mechanisms in all probability could disguise even a well defined action. It has been recognized that both 'old' and newly discovered peptides may be involved in the regulation of food intake. Recently the first disease-related mutation in a peptidergic system has been identified, and clinical efficacy of a substance P antagonist for treatment of depression has been reported. Taken together it seems that peptides may play a role particularly when the nervous system is stressed, challenged or afflicted by disease, and that peptidergic systems may, therefore, be targets for novel therapeutic strategies.