The effect of exposure to nanoparticles and nanomaterials on the mammalian epigenome

Human exposure to nanomaterials and nanoparticles is increasing rapidly, but their effects on human health are still largely unknown. Epigenetic modifications are attracting ever more interest as possible underlying molecular mechanisms of gene–environment interactions, highlighting them as potential molecular targets following exposure to nanomaterials and nanoparticles. Interestingly, recent research has identified changes in DNA methylation, histone post-translational modifications, and noncoding RNAs in mammalian cells exposed to nanomaterials and nanoparticles. However, the challenge for the future will be to determine the molecular pathways driving these epigenetic alterations, the possible functional consequences, and the potential effects on health.

Pressurized liquid extraction of Neochloris oleoabundans for the recovery of bioactive carotenoids with anti-proliferative activity against human colon cancer cells

In recent years, the green microalgae Neochloris oleoabundans have demonstrated to be an interesting natural source of carotenoids that could be used as potential food additive. In this work, different N. oleoabundans extracts obtained by pressurized liquid extraction (PLE) have been analyzed in depth to evaluate the influence of different culture conditions (effect of nitrogen, light intensity or carbon supplied) not only on the total carotenoid content but also on the carotenoid composition produced by these microalgae. Regardless of the cultivation conditions, lutein and carotenoid monoesters were the most abundant carotenoids representing more than 60% of the total content in all extracts. Afterwards, the effect of the different N. oleoabundans extracts and the dose-effect of the most potent algae extracts (namely, N9, PS and CO₂ (-)) on the proliferation of human colon cancer cells lines (HT-29 and SW480) and a cell line established from a primary colon cancer cell culture (HGUE-C-1) were evaluated by an MTT assay whereas a stepwise multiple regression analysis was performed to get additional evidences on the relationship between carotenoid content and the antiproliferative activity. Results revealed that, as a general trend, those extracts with high total carotenoid content showed comparably antiproliferative activity being possible to establish a high correlation between the cell proliferation values and the carotenoid constituents. Monoesters showed the highest contribution to cell proliferation inhibition whereas lutein and violaxanthin showed negative correlation and diesters and zeaxanthin showed a positive significant contribution to cell proliferation.

Use of herbs, spices and their bioactive compounds in active food packaging

Natural additives obtained from herbs and spices are being increasingly used in the food packaging industry.

Amygdala kindling differentially regulates the expression of the elements involved in TRH transmission

Subthreshold electrical stimulation of the amygdala (kindling) activates neuronal pathways increasing the expression of several neuropeptides including thyrotropin releasing-hormone (TRH). Partial kindling enhances TRH expression and the activity or its inactivating ectoenzyme; once kindling is established (stage V), TRH and its mRNA levels are further increased but TRH-binding and pyroglutamyl aminopeptidase II (PPII) activity decreased in epileptogenic areas. To determine whether variations in TRH receptor binding or PPII activity are due to regulation of their synthesis, mRNA levels of TRH receptors (R1, R2) and PPII were semi-quantified by RT-PCR in amygdala, frontal cortex and hippocampus of kindled rats sacrificed at stage II or V. Increased mRNA levels of PPII were found at stage II in amygdala and frontal cortex, and of pro-TRH and TRH-R2, in amygdala and hippocampus. At stage V, pro-TRH mRNA levels increased and those of PPII, decreased in the three regions; TRH-R2 mRNA levels diminished in amygdala and frontal cortex and of TRH-R1 only in amygdala. In situ hybridization analyses revealed, at stage II, enhanced TRH-R1 mRNA levels in dentate gyrus and amygdala while decreased in piriform cortex; those of TRH-R2 increased in amygdala, CA2, dentate gyrus, piriform cortex, thalamus and subiculum and of PPII, in CAs and piriform cortex. In contrast, at stage V decreased expression of TRH-R1 occurred in amygdala, CA2/3, dentate gyrus and piriform cortex; of TRH-R2 in CA2, thalamus and piriform cortex, and of PPII in CA2, and amygdala. The magnitude of changes differed between ipsi and contralateral side. These results support a trans-synaptic modulation of all elements involved in TRH transmission in conditions that stimulate the activity of TRHergic neurons. They show that reported changes in PPII activity or TRH-binding caused by kindling relate to regulation of the expression of TRH receptors and degrading enzyme.

Coadministration of tacrolimus and ketoconazole in renal transplant recipients: cost analysis and review of metabolic effects

BACKGROUND

The high cost of tacrolimus is a major problem in Mexico. Ketoconazole increases tacrolimus bioavailability by inhibiting cytochrome P450 3A4 and glycoprotein-p.

OBJECTIVE

To demonstrate that the coadministration of tacrolimus and ketoconazole allows a significant dose and cost reduction.

PATIENTS AND METHODS

This prospective study administered tacrolimus and ketoconazole to renal transplant recipients with dose adjustment according to tacrolimus blood levels. At 0-1, 1-6, 6-12, and 12-24 months posttransplant demographic, transplant type, immunosuppression, and clinical data were reviewed. The cost of tacrolimus treatment was calculated based on the dose used as compared to the recommended dose (0.15-0.20 mg/kg/d).

RESULTS

Eleven patients with an age of 40 years (range, 13-71) were studied from May 2000 to August 2002. Follow-up was 15 +/- 10 months. Graft source was living donor in six patients and cadaveric in five. All patients received tacrolimus + mycophenolate mofetil + prednisone. The mean ketoconazole dose was 87 mg/d. Since the dose of tacrolimus was 0.04 mg/kg/d versus the recommended dose of 0.15-0.20 mg/kg/d, there was a 78% cost reduction (P =.000). Tacrolimus blood levels remained in the therapeutic range. There were no drug-related side effects.

CONCLUSIONS

The co-administration of tacrolimus and ketoconazole results in a substantial dose and cost reduction while maintaining therapeutic levels. No adverse metabolic consequences were seen with this combination.

[Study of hepatitis B virus replication and infection by other hepatitis viruses in patients with chronic hepatitis B virus infection]

AIM

To study hepatitis B virus (HBV) replication in a series of patients with HBV infection and to analyze the frequency of associated hepatitis C virus (HCV) and hepatitis D (HDV) infection.

PATIENTS AND METHOD

Serological markers of HBV, HCV and HDV, transaminase values and HBV DNA were studied in serum samples from 463 patients with chronic HBV infection.

RESULTS

Three hundred ninety-six (85.5%) were classified as hepatitis B, 33 (7.1%) as hepatitis B and C, 17 (3.6%) as hepatitis B and D and 17 (3.6%) as hepatitis B, C and D. Sixty-seven percent of patients with hepatitis B and 33% of those with chronic hepatitis B were asymptomatic HBsAg carriers. HVB DNA was identified in 27.7% of patients with hepatitis B, in 24% of those with hepatitis B and C, in 11.7% of those with hepatitis B and D and in 29.4% of those with hepatitis B, C and D. HBV DNA and elevated transaminase levels were found in 63% of HBeAg-positive patients and in only 16% of those who were anti-HBe-positive. These latter were considered candidates for antiviral treatment.

CONCLUSIONS

In our environment, most patients with HBV infection are asymptomatic HBsAg carriers. Viral replication and elevated alanine aminotransferase levels were found in 22% of the patients. Consequently, these patients are candidates for antiviral treatment. Between 3.6% and 7.1% of patients with hepatitis B presented coinfection with HCV or HDV, or both. No significant differences were found in HBV replication among the different groups.

Survival evaluation of treatment modality in squamous cell carcinoma of the oral cavity and oropharynx

The treatment of squamous cell carcinoma of the mouth and oropharynx continues to change. In this primary report, we compared the results obtained by combined surgery and radiation therapy, or either modality alone. Other methods such as brachytherapy, or hyperfractionated radiotherapy, were not included in our protocols. A statistical analysis of the 3- and 5-year survival rates in relation to location and size of the primary tumour, stage at initial presentation, treatment modality and recurrence, was carried out in 88 patients with squamous cell carcinoma of the oral cavity or oropharynx. The overall survival rate was 73.8% at 3 years and 66.3% at 5 years. Size of tumour and stage at presentation were significant when P value was adjusted by site. Survival was significantly associated with type of treatment (combined approach obtained superior results), location of primary tumour, and recurrence. The type of neck dissection did not show any effect. Therapeutic modality used, stage, and location of primary tumour significantly influenced survival. A more selective combined initial treatment according to site and stage (distribution) is recommended.

Effects of a toxin from the mucus of the Caribbean sea anemone (Bunodosoma granulifera) on the ionic currents of single ventricular mammalian cardiomyocytes

The effects were studied of a toxin (Bainh) isolated from the secretion of the Caribbean sea anemone Bunodosoma granulifera on electrical and mechanical activities of rat ventricular muscle. The effects on the ionic currents of single rat and dog ventricular cardiomyocytes were studied using the whole-cell recording patch-clamp technique. In the concentration range from 1 to 10 mg/ml, Bainh increased the force of contraction and induced an increase in action potential duration of ventricular multicellular preparations. In single cardiomyocytes, at concentrations up to 10 mg/ml Bainh showed no significant effects on the sodium current. However, at 0.5-1 mg/ml it increased the L-type Ca current (ICaL) by 25-50%. This increase in ICaL was not voltage dependent and was reversible after washout. The transient outward current was not significantly affected by Bainh (1-10 mg/ml). In this concentration range, Bainh markedly (approximately 75%) increased the inward-going rectifier current, IKI. This effect that was not voltage dependent and was fully reversible upon returning to control solution. It is suggested that these effects on ionic currents could explain the positive inotropic action of Bainh on cardiac multicellular preparations.

[Potter syndrome caused by bilateral renal agenesis and duodenal atresia]

A case of Potter syndrome secondary to renal agenesia and duodenal atresia with anular pancreas is presented. The karyotype was 47 XY-21. We discuss the antenatal diagnosis and the perinatal management.

[Gastric emptying of fluids and gallbladder contraction in non-ulcer dyspepsia]

Non-ulcer dyspepsia is a frequent clinical entity characterized by chronic upper gastrointestinal symptoms without organic lesions by radiology, sonography or endoscopy. We studied simultaneously the rate of gastric emptying and gallbladder contraction in 10 patients with non-ulcer dyspepsia and in 10 healthy controls after ingestion of 500 cc of isotonic saline, and 500 cc of a liquid mixed meal, hypercaloric and hyperosmotic. The measurements were done by direct real-time ultrasonic imaging in fasting and were repeated at regular intervals (15-30 minutes) after the liquid meal, until complete gastric emptying was established. We found with the liquid mixed meal, the patients with non-ulcer dyspepsia had a significant delay in gastric emptying and gallbladder hypokinesis with faulty contraction and slow refilling. Dynamic ultrasonographic studies are useful in patients with non-ulcer dyspepsia.

[Antibodies against hepatitis C virus. Experience with a second generation test]

A second generation recombinant immunoblot assay to detect antibodies against Hepatitis C virus (RIBA II, Ortho Diagnostic Systems) was applied to 30 serum samples repeatedly reactive to ELISA anti-HCV c100-3, 11 from hemodialysis patients, 11 from patients with chronic hepatitis and 8 from patients with cirrhosis. The assay detects individual antibodies directed to 4 antigenic components of the C virus, 2 antigens, c100 and 5-1-1 contained in the original ELISA assay and 2 new antigens, c33c and c22-3 the latter structural in nature. From the total of 30 samples, 23 (77%) were reactive, 4 (13%) indeterminate and 3 (10%) non reactive to the RIBA II assay. Much variation was observed regarding the response to each individual antigen. c22-3 was the most frequently reactive with the highest intensity. RIBA II assay confirmed a high percentage of the reactive results with the ELISA c-100-3, serum samples that were non reactive to RIBA showed a low optical density with ELISA. c22-3 was the most sensitive antigenic component.

[Antibodies against hepatitis C virus in patients with liver diseases and in risk subjects. Preliminary report]

The recent discovery of an antigenic component of the causative agent of Non-A, Non-B hepatitis, has led to the characterization of this virus--Hepatitis C Virus (HCV)--and to the identification of an antibody present in infected subjects (anti-HCV) detected by means of the C-100 antigen derived from a nonstructural region of the viral genome. Using a commercial Kit (Ortho Diagnostic Inc.), the incidence of anti-HCV antibody was studied in the Military Hospital "Dr. Carlos Arvelo" of Caracas, Venezuela with the following results: Health personnel (doctors, nurses, laboratory staff): 102 persons studied, 2 positives (1.96%); 16 patients in chronic hemodialysis: 6 positives (33%); 20 subjects with antibodies against HIV virus, confirmed by Western Blot: 7 positives (35.4%). Of 10 patients with Surface Antigen negative Chronic Hepatitis, 7 (70%) positive for anti-HCV, of 25 patients with cirrhosis: 12 positive (48%), 2 patients with hepatocarcinoma 1 positive (50%). There was also a high incidence of total anti-core antibodies in the patients studied. The results suggest that the hepatitis C virus could be playing an important role as a causative factor of liver diseases in our Country.