Ultrasound-assisted depolymerization of kappa-carrageenan and characterization of degradation product.

Degradation of polysaccharides to afford low-molecular-weight oligosaccharides have been shown to produce new bioactivities that are not present in the starting material. The simplicity of ultrasonic treatment in the degradation of a polysaccharide, such as κ-carrageenan, offers practical advantage in producing degraded products with lower molecular weight that may have new interesting potential activities. This study embarked on investigating the effects in molecular weights and structural changes of κ-carrageenan under varying ultrasonic conditions. Molecular weight (MW) monitoring of ultrasonically-treated κ-carrageenan at various conditions were done by gel permeation chromatography. The product formed using the optimized condition was characterized using FTIR and NMR. The decrease in MW has been shown to be dependent on low concentration (5.0 mg mL-1), high amplitude (85%), and long treatment time (180 mins) to afford a degraded κ-carrageenan with average molecular weight (AMW) of 41,864 Da, which is a 96.33% reduction from the raw sample with initial AMW of 1,139,927 Da. Structural analysis reveals that most of the peaks of the raw κ-carrageenan was retained with minor change. 1D and 2D NMR analyses showed that the sonic process afforded a product where the sulfate group at the G4S-4 position was cleaved forming a methylene in the G4S ring. The results would be useful in the structure-activity relationship of κ-carrageenan oligosaccharides and in understanding the effect in the various potential applications of degraded κ-carrageenan.

Cytotoxic and Apoptotic Activity of Aglaforbesin Derivative Isolated from Aglaia loheri Merr. on HCT116 Human Colorectal Cancer Cells.

BACKGROUND: The genus Aglaia (Meliaceae) is an established source of many anticancer compounds. The study evaluated the leaf extracts of Aglaia loheri, a tree native to the Philippines, as potential source of anticancer compounds. METHODS: Using bioassay-guided fractionation, A. loheri leaf extract was subjected to various chromatographic techniques and step-wise application of MTT assay on human colorectal carcinoma cells, HCT116, to determine the cytotoxic fractions. The most cytotoxic HPLC isolate was structurally identified using 1D and 2D NMR and its apoptotic effect was assessed by JC-1 staining, caspase 3/7 assay and TUNEL assay. RESULTS: After stepwise chromatography fractionation, an HPLC isolate, structurally identified as aglaforbesin derivative (AFD), demonstrated potent cytotoxicity against HCT116. AFD exhibited strong toxicity (IC50 = 1.13 ±0.07 µg/mL) and high selectivity on HCT116 than normal human kidney cells (HK-2). AFD-induced toxicity to HCT116 is possibly through the stimulation of the apoptotic signaling pathway via caspase 3/7 activation and DNA fragmentation independent of mitochondrial membrane depolarization. CONCLUSION: AFD exhibited selective cytotoxicity and apoptotic activity to HCT116 and could be further developed as anticancer drug lead.

Regenerable Acidity of Graphene Oxide in Promoting Multicomponent Organic Synthesis.

The Brønsted acidity of graphene oxide (GO) materials has shown promising activity in organic synthesis. However, roles and functionality of Lewis acid sites remain elusive. Herein, we reported a carbocatalytic approach utilizing both Brønsted and Lewis acid sites in GOs as heterogeneous promoters in a series of multicomponent synthesis of triazoloquinazolinone compounds. The GOs possessing the highest degree of oxidation, also having the highest amounts of Lewis acid sites, enable optimal yields (up to 95%) under mild and non-toxic reaction conditions (85 °C in EtOH). The results of FT-IR spectroscopy, temperature-programed decomposition mass spectrometry, and X-ray photoelectron spectroscopy identified that the apparent Lewis acidity via basal plane epoxide ring opening, on top of the saturated Brønsted acidic carboxylic groups, is responsible for the enhanced carbocatalytic activities involving Knoevenagel condensation pathway. Recycled GO can be effectively regenerated to reach 97% activity of fresh GO, supporting the recognition of GO as pseudocatalyst in organic synthesis.

Plasmodium chabaudi chabaudi malaria parasites can develop stable resistance to atovaquone with a mutation in the cytochrome b gene.

BACKGROUND: Plasmodium falciparum, has developed resistance to many of the drugs in use. The recommended treatment policy is now to use drug combinations. The atovaquone-proguanil (AP) drug combination, is one of the treatment and prophylaxis options. Atovaquone (ATQ) exerts its action by inhibiting plasmodial mitochondria electron transport at the level of the cytochrome bc1 complex. Plasmodium falciparum in vitro resistance to ATQ has been associated with specific point mutations in the region spanning codons 271-284 of the cytochrome b gene. ATQ -resistant Plasmodium yoelii and Plasmodium berghei lines have been obtained and resistant lines have amino acid mutations in their CYT b protein sequences. Plasmodium chabaudi model for studying drug-responses and drug-resistance selection is a very useful rodent malaria model but no ATQ resistant parasites have been reported so far. The aim of this study was to determine the ATQ sensitivity of the P. chabaudi clones, to select a resistant parasite line and to perform genotypic characterization of the cytb gene of these clones. METHODS: To select for ATQ resistance, Plasmodium. chabaudi chabaudi clones were exposed to gradually increasing concentrations of ATQ during several consecutive passages in mice. Plasmodium chabaudi cytb gene was amplified and sequenced. RESULTS: ATQ resistance was selected from the clone AS-3CQ. In order to confirm whether an heritable genetic mutation underlies the response of AS-ATQ to ATQ, the stability of the drug resistance phenotype in this clone was evaluated by measuring drug responses after (i) multiple blood passages in the absence of the drug, (ii) freeze/thawing of parasites in liquid nitrogen and (iii) transmission through a mosquito host, Anopheles stephensi. ATQ resistance phenotype of the drug-selected parasite clone kept unaltered. Therefore, ATQ resistance in clone AS-ATQ is genetically encoded. The Minimum Curative Dose of AS-ATQ showed a six-fold increase in MCD to ATQ relative to AS-3CQ. CONCLUSIONS: A mutation was found on the P. chabaudi cytb gene from the AS-ATQ sample a substitution at the residue Tyr268 for an Asn, this mutation is homologous to the one found in P. falciparum isolates resistant to ATQ.

[Laparoscopic surgical treatment of cholecysto-choledochal calculi. A single step solution]. / Trattamento chirurgico laparoscopico della calcolosi colecisto-coledocica. La soluzione in un unico atto.

The laparoscopic era has created a new basis for the management of choledocholithiasis. Many surgeons now regard laparoscopic cholecystectomy and exploration of the common bile duct as the "gold standard". The main advantages of single-stage treatment consist in a significantly shorter hospital stay, very low complication rates and a reduction of average hospital costs. Among 601 cases of cholelithiasis treated over the period from 1994 to 1999, we report 73 cases of common-bile-duct stones. Surgical sphincterotomy was performed in 20 cases and endoscopic sphincterotomy in 24; only in 7 cases was choledochotomy and/or hepaticojejunostomy (3 cases) performed for critical situations. Twenty-two cases of cholelithiasis were treated by laparoscopic cholecystectomy and exploration of the common bile duct. Stone extraction was obtained with a balloon catheter or Dormia basket via a choledochotomy. Surgery was completed by suturing, cholangiography and the placement of sub-hepatic drainages. No mortality or long-term complications were recorded with the laparoscopic procedure; only two immediate complications were reported, both of which were biliary leakages (9%) that resolved spontaneously. With the other procedures, high rates of mortality, morbidity, hospital admissions and technical failure were registered. We regard laparoscopic exploration of the common bile duct as the treatment of choice for bile-duct stones when combined with cholecystectomy. We reserve ERCP plus endoscopic sphincterotomy only for common-bile-duct stones alone, without a gallbladder or gallstones. Open surgery is performed in particular situations such as Mirizzi's syndrome or when other procedures have failed to yield satisfactory results.

[The laparoscopic treatment of esophageal achalasia. Our experience]. / Trattamento laparoscopico dell'acalasia esofagea. Nostra esperienza.

BACKGROUND: Laparoscopic Heller myotomy combined with a Dor fundoplication is considered the procedure of choice to treat esophageal achalasia. The aim of this study is to report a personal experience and to analyse the controversial aspect of this procedure. METHODS: From January 1997 to March 1998 six patients with esophageal achalasia were treated by Heller laparoscopic myotomy with anterior fundoplication. RESULTS: There was one intraoperative perforation of esophageal mucosa, sutured laparoscopically with non postoperative sequelae. There were no surgical mortality and no postoperative morbidity. Complete relief of dysphagia in five of six patients, the good clinical and instrumental results and the satisfaction of these patients, lead to a prudent optimism. CONCLUSIONS: Personal initial experience, although the little number of patients and the short follow-up, confirms that laparoscopic cardiomyotomy is a safe and effective procedure for the treatment of esophageal achalasia.

[The epiphrenic esophageal diverticulum. Its transhiatal laparoscopic treatment]. / Diverticolo esofageo epifrenico. Trattamento laparoscopico trans-iatale.

A new laparoscopic surgical approach to treat an esophageal epiphrenic diverticulum is described. This is a rare disease. Today only 4 cases of laparoscopic transhiatal treatment with good results are reported in the literature. The present case report is an 80 years-old male with medium size epiphrenic diverticulum (10 cm) and very symptomatic dysphagia. Preoperative investigations include barium swallow, upper gastrointestinal endoscopy and esophageal manometry. The laparoscopic transhiatal treatment was carried out without difficulty. Diverticulectomy esophageal myotomy and partial gastric fundoplication (Dor) were performed. No postoperative complication was recorded and optimal result was achieved. In conclusion, the efficacy of laparoscopic approach is underlined and the short and medium-term results are satisfactory.

[Laparoscopic incidental diagnosis: treatment during laparoscopic surgery]. / Patologie incidentali in chirurgia laparoscopica. Quale atteggiamento?

BACKGROUND: The authors consider the importance of laparoscopic exploration of the abdominal cavity for the diagnosis of mistaken preoperative pathologies, during laparoscopic surgery. RESULTS: In our series the incidental diagnosis is 5.3%. CONCLUSIONS: The additional treatment diagnosis is realized when there is no great surgical engagement or when there are risks for the patient's life (i.e.: hemorrhagic ovarian cyst). In case of incidental neoplasia diagnosis it would been more appropriate to do a biopsy only, for typing. The realization of demanding or non-programmed surgical operations must be consequent on written consent.

Human leucocyte interferon-alpha in chronic hepatitis C resistant to recombinant or lymphoblastoid interferon-alpha: a randomized controlled trial.

Patients with biopsy-proven chronic hepatitis C, who failed to respond to a previous course of either recombinant (rIFN-alpha) or lymphoblastoid (Ly IFN-alpha) interferon-alpha, were randomized to receive either leucocyte (Le) IFN-alpha (patients) or a second course of the same IFN-alpha (controls), to compare the efficacy and safety of these treatment schedules. All patients received the same dose of IFN-alpha as was used during their previous treatment (3 million units (MU) or 6 MU three times weekly) for 6 months. Patients with a normal alanine aminotransferase (ALT) value at month 6 were treated for a further 6 months. All patients were followed-up for 12 months after treatment. A total of 69 patients were enrolled, 44 in the Le IFN-alpha group and 25 in the control group. At the end of the treatment period, 13 of the 44 patients (29.5%) in the Le IFN-alpha group had a biochemical response (normal ALT) and six of 44 (13.6%) patients had undetectable serum hepatitis C virus (HCV) RNA. At the end of the follow-up period, 10 patients (22.7%) had normal ALT values and serum HCV RNA was undetectable in three (6.8%). None of the patients in the control group showed normal ALT values at any time. Genotype 1b tended to be more frequent among non-responders (61 vs 45%): basal gamma-glutamyl transpeptidase (gamma-GT) values were lower in responders than in non-responders (33.3 +/- 11.70 Ul-1 vs 58.4 +/- 33.04; P = 0.01). Le IFN-alpha was well tolerated by all patients. These results support the use of Le IFN-alpha in patients with chronic hepatitis C who are non-responders to a previous treatment with recombinant or lymphoblastoid IFN-alpha.

Combination low-dose lymphoblastoid interferon and thymosin alpha 1 therapy in the treatment of chronic hepatitis B.

This open label study was initiated to assess the safety and efficacy of lymphoblastoid interferon-alpha (IFN-alpha) and thymosin alpha 1 (T alpha 1) in the treatment of 11 patients with chronic hepatitis B, who had failed to respond to standard IFN-alpha 2b therapy, and in four interferon naive patients. These fifteen hepatitis B surface antigen (HBsAg) positive and serum hepatitis B virus (HBV) DNA positive patients were given T alpha 1 (1 mg) subcutaneously (s.c.) on 4 consecutive days. Low-dose lymphoblastoid IFN-alpha (3 MU) was administered intramuscularly (i.m.) on the fourth day. Beginning with the second and for the subsequent 25 weeks, patients self-administered T alpha 1 twice weekly in the morning followed, 12 h later, by 3 million units (MU) lymphoblastoid IFN-alpha. Patients were followed-up for 12 months. Nine (60%) of the 15 patients, including six (55%) of the 11 patients previously treated with IFN-alpha 2b, responded by losing serum HBV DNA and normalizing alanine aminotransferase (ALT) values. Six of the nine responders seroconverted to HBsAg negativity. Significant improvements in the Knodell histological activity index were observed in the responders and no significant adverse effects were observed. Combination low-dose lymphoblastoid IFN-alpha and T alpha 1 treatment may provide a safe and potentially effective therapeutic approach in chronic hepatitis B. These results require confirmation in future randomized controlled studies.

Intracholecystic hemorrhage: an atypical complication after liver needle biopsy.

The authors report an unusual case of intracholecystic hemorrhage related to liver biopsy in a 23-year-old man. Echography and computed tomography evidenced changes in density within the gallbladder which were probably caused by hemorrhagic discharge. Although the mechanism by which liver biopsy induced intracholecystic hemorrhage is unclear, the authors believe that this iatrogenic complication was probably the result of microlesions of the gallbladder wall caused by needle puncture: the lesions extended into the submucosa and provoked slow hematic leakage. The pain syndrome began 48 hours after biopsy. The peculiarity of this case report was confirmed by the fact that no bile was aspirated, no choleperitoneum was found, and no gallbladder tissue was detected in the sample. The authors conclude by recommending clinical and echographic control following liver biopsy.

Hepatic damage after danazol treatment.

A case of liver damage following treatment with Danazol for fibrocystic breast disease is reported. The findings are based on liver histology and the exclusion of other causes of liver damage.

[Therapeutic action of vitamin C on cholesterol metabolism]. / Azione terapeutica della vitamina C sul metabolismo del coleste rolo.

As a part of the research work on the role played by Vitamin C on lipidic metabolism, the effects on man were considered that result from the administration of high vitamin C doses, chiefly with reference to the serum levels of colesterol, of total lipids and of triglycerides. Our research was conducted on male subjects of 65-90 years, who were administered 3 g/day of vitamin C for three weeks. Our findings show that the administration of high vitamin C doses causes a statistically significant decrease in colesterol, in total lipids and in triglycerides, in all the subjects under consideration. This takes place not only when colesterol, total lipids and triglycerides present normal serum levels, but also when such levels show an increase. Conversely, vitamin C significantly increases, with treatment, in all subjects treated, both in plasma and in leukocytes.