Beneficial effect of oral administration of zinc sulfate on 5-fluorouracil-induced gastrointestinal mucositis in rats.

OBJECTIVE: This experimental study explored the potential of oral zinc sulfate to protect the gut mucosa from 5-fluorouracil (5-FU)-induced degenerative lesions in Wistar rats. MATERIALS AND METHODS: Female Wistar rats were used and divided into 2 interventional groups (Z with 6 animals and F with 5 animals) and one control group (M with 5 rats). After 2 hours of fasting, group Z received via oral gavage 1.5 ml of solution, corresponding to 15 mg zinc sulfate for 9 consecutive days. Groups F and M received only the vehicles. On day 3, 400 mg/kg of 5-FU was administered intraperitoneally to groups Z and F. Tissue samples were collected from the duodenum, jejunum, colon and liver. Histological assessment for each gastrointestinal tract segment was determined semi-quantitatively by rating 11 histological features from normal (0) to severe (3). The independent groups were analyzed using the Kruskal-Wallis test and the Mann-Whitney U-test, with a Bonferroni correction for alpha (p ≤ 0.016). RESULTS: In group F the jejunum was the most affected area with a mean histological score of  27 (25-32). In the Z group, significantly lower histological scores were obtained compared with group F (duodenum Z vs. F: U = 0, p = 0.004; jejunum Z vs. F: U = 0, p = 0.006 and colon: Z vs. F: U = 0, p = 0.005). Graded liver necro-inflammatory lesions were significantly lower in group Z compared with group F (U = 0, p = 0.004), suggesting fewer bacterial intestinal translocation processes. CONCLUSIONS: Zinc sulfate has a beneficial role, decreasing the severity of gut mucosal injuries induced by 5-FU in Wistar rats.

Rifaximin modulates 5-fluorouracil-induced gastrointestinal mucositis in rats.

OBJECTIVE: This study assessed the protective potential of rifaximin in 5-fluorouracil (5-FU) induced intestinal mucositis in the Wistar rats'. MATERIALS AND METHODS: Twenty-nine Wistar rats were divided into 4 interventional groups of 6 animals (A, B, C and F) and one control group (M) of 5 animals. Groups A, B and C received for three days consecutively rifaximin orally: 50 mg/kg (group A), 100 mg/kg (group B) and 200 mg/kg (group C). In the fourth day, 500 mg/kg of 5-FU was administered intraperitoneally to the groups A, B, C and F. A semi-quantitative histological assessment for duodenum, jejunum and colon were obtained by rating 11 histological characteristics of mucositis from 0 (normal) to 3 (severe). Semi-quantitative grades were a measure for TLR4 immunopositive cells. Statistical comparisons used - U Test, with a Bonferroni correction for alpha (p ≤ 0.016). RESULTS: In the group F the most affected areas were the jejunum (median histological score 25) and the duodenum (median histological score 22). The assessment of duodenum histological lesions depicted significant difference between F and B groups (U = 1.5, p = 0.007) and between F and C groups (U = 0, p = 0.003). Graded microscopic degenerative lesions on jejunum were significantly different between F and C groups (U = 0, p = 0.004). Graded TLR4 immunopositive cells in the jejunum surface epithelium was significantly different between groups F and C (U = 2.5, p = 0.006). In the colonic mucosa, significantly differences were noted on microscopic degenerative lesions between F and A groups (U = 0, p = 0.004) and between F and C groups (U = 0, p = 0.004). CONCLUSIONS: Pretreatment with 200 mg/kg of rifaximin for 3 consecutive days proved efficient in preventing intestinal mucosal degenerative lesions induced by 5-FU.

Chronic pancreatitis with hemosuccus pancreaticus. The diagnostic contribution of computed tomography and contrast enhanced ultrasonography--case report.

Hemosuccus pancreaticus is defined as upper gastrointestinal hemorrhage from the ampulla of Vater via the pancreatic duct. It is a rare disease, with non-specific presentation, challenging to diagnose and difficult to treat, with high mortality rates in untreated patients with massive bleeding. Given the intermittent nature of the bleeding, delays in diagnosis frequently occur. Timely diagnosis and treatment seem to result in markedly reduced mortality, therefore we emphasize the diagnostic contribution of imaging techniques by presenting the case of a patient with chronic pancreatitis in whom computed tomography established the diagnosis of blood in the Wirsung duct and contrast-enhanced ultrasound brought its added value by excluding the active bleeding.

Effects of rifaximin on indomethacin-induced intestinal damage in guinea-pigs.

AIM: Enterobacterial translocation into the gut mucosa is the first step required for activation of neutrophils and inducible nitric oxide synthase (iNOS), involved in the pathogenesis of indomethacin-induced intestinal lesions. Rifaximin may limit NSAID-associated intestinal damage by decreasing the bacterial load. We aimed to study the effect of rifaximin on indomethacin-induced intestinal damage in guinea-pigs. MATERIALS AND METHODS: Twenty-four guinea pigs, equally divided in four interventional groups (A-D), received indomethacin, given orally once daily (30 mg/kg) for three consecutive days. In groups B, C, D different doses of rifaximin (50 mg/kg, 100 mg/kg and 200 mg/kg) were given orally two hours before indometachin administration. Semi-quantitative grades were measure for gross findings, degenerative lesions, neutrophils and eosinophils infiltrates and iNOS immunopositivity. Statistical comparisons used Mann Whitney Test, with a Bonferroni correction for alpha (p ≤ 0.016). RESULTS: Statistical analysis of graded gross findings, microscopic degenerative lesions, endothelium damage and iNOS immunopositivity found no difference between A and B groups. Significant fewer gross findings (U = 3, p = 0.015), microscopic degenerative lesions (U = 2, p = 0.008) and lower grades for iNOS immunopositivity (U = 0, p = 0.002) were found in group C compared with group A. In group D, significant lower grades for iNOS immunopositivity were obtained (U = 0, p = 0.002) compared with group A and fewer degenerative lesions without reaching statistical significance (U = 4, p = 0.026). CONCLUSIONS: 100 mg/kg of rifaximin proved efficient in preventing gut degenerative lesions induced by indomethacin in a guinea pig model, the iNOS activity being significantly decreased.

Contrast magnetic resonance imaging for measurement of cartilage glycosaminoglycan content in dogs: a pilot study.

OBJECTIVE: To assess the ability of a contrast-enhanced magnetic resonance imaging (MRI) technique to quantitatively determine glycosaminoglycan content in canine articular cartilage. METHODS: Fifty-four full-thickness cartilage discs were collected from the femorotibial and scapulohumeral joints of three adult dogs immediately following euthanasia. One set of discs from each dog was analysed for glycosaminoglycan content using a colourimetric laboratory assay. The remaining position-matched set of discs from contralateral limbs underwent pre- and post-contrast gadolinium-enhanced MRI, using repeated saturation recovery pulse sequences which were used to generate calculated T1 maps of the cartilage discs. Linear regression analysis was then performed relating delayed gadolinium-enhanced MRI T1 calculated signal intensity to the cartilage glycosaminoglycan content normalized to DNA content. Repeatability of triplicate measurements was estimated by calculating the coefficient of variation. RESULTS: Mean coefficient of variation estimates for the gadolinium-enhanced MRI T1 signal intensity values for nine sampling sites from three dogs ranged from 5.9% to 7.5%. Gadolinium-enhanced MRI T1 signal intensity was significantly correlated (p <0.05) with normalized glycosaminoglycan content in two dogs (r = 0.79, p = 0.011; r = 0.78, p = 0.048), but not in the third dog (r = 0.53, p = 0.071). CLINICAL SIGNIFICANCE: Gadolinium-enhanced MRI assessment of cartilage may be predictive of glycosaminoglycan content and therefore offer an in vivo assessment of changes in cartilage characteristics over time. Additional studies appear indicated to determine the reliability and clinical applicability of gadolinium-enhanced MRI in detecting changes in cartilage over time.

An eight-coil high-frequency probehead design for high-throughput nuclear magnetic resonance spectroscopy.

In order to increase the throughput of high-resolution nuclear magnetic resonance spectroscopy a multiple-coil probe, which enables the simultaneous analysis of eight different samples, was designed. The probe, consisting of eight identical solenoidal coils, was constructed for operation at 600 MHz. By using four receivers and radiofrequency switches, spectra from eight different chemical solutions were acquired in the time normally required for one. Two-dimensional COSY, gradient COSY, and TOCSY data have been acquired. Intercoil electrical isolation was between 25 and 45 dB, with signal cross-talk between approximately 1 and 5% measured by NMR. The spectral linewidths for the eight coils were between 3 and 6Hz for a single optimized shim setting.

3D micron-scale MRI of single biological cells.

We report MRI microscopy images of single biological cells with micron-scale resolution in all three dimensions. Sub-cellular organelles are observed, including a spiral-shaped array of chloroplasts on the inner surface of the cell wall of a Spirogyra alga.

3D MR microscopy with resolution 3.7 microm by 3.3 microm by 3.3 microm.

The technique of magnetic resonance imaging microscopy holds promise of bringing the full capabilities of NMR to arbitrarily specified positions within spatially inhomogeneous systems, including biological cells, yet the possibilities are limited by the need for adequate sensitivity and spatial resolution. We report proton magnetic resonance images obtained by combining advances in receiver coil sensitivity, gradient strength, and pulse/gradient sequence design. We achieve resolution of 3.7 +/- 0.4 microm by 3.3 +/- 0.3 microm by 3.3 +/- 0.3 microm for a volume resolution approximately 40 femtoliters (corresponding to approximately 3 x 10(12) proton spins).

Synthesis and steroid sulphatase inhibitory activity of C19- and C21-steroidal derivatives bearing a benzyl-inhibiting group.

Two series of compounds, benzyl alkylated at position 17alpha and 20 of androstane and pregnane, respectively, were synthesised and tested for steroid sulphatase inhibition. We compared the ability of the compounds to inhibit steroid sulphatase obtained from two different sources (homogenates of transfected HEK-293 cells and Jeg-3 cells) and with two types of substrate (DHEAS or E(1)S). The inhibitory activity of 17alpha-benzyl-5alpha-androstane-3beta,17beta-diol (7), 17alpha-benzyl-5-androstene-3beta,17beta-diol (9), 17alpha-benzyl-4,17beta-dihydroxy-4-androsten-3-one (15) and 20-benzyl-5-pregnene-3beta,20alpha-diol (16) has proven to be superior to that of danazol, the first steroid sulphatase inhibitor to be reported, but still lower than that of the potent inhibitor estrone-3-O-sulphamate. The inhibitory activity of compound 7 was as potent as that of its previously reported estrane analogue, 17alpha-benzyl estradiol. Benzyl alkylated compounds with no OH group on the A-ring (with a 4-OCH(3), 4-Cl, or 4-H and their precursor epoxides), as well as a series of basic steroids without a benzyl group (ADT, epi-ADT, 3alpha-diol, 3beta-diol, DHEA, Delta(5)-diol, DHT, T, Preg and Prog), did not show steroid sulphatase inhibition. We have thus demonstrated that the steroid sulphatase inhibitory effect of a benzyl group, previously observed for an estrane nucleus, can be extended to certain androstane and pregnane nuclei bearing a 3beta-OH or a 4-OH group. Inhibitors 7, 9, 15 and 16 did not induce any proliferative effect on androgen-sensitive Shionogi cells. However, when tested on oestrogen-sensitive ZR-75-1 cells, a proliferative effect was observed for 7 and 9, but not for 15 and 16.

Potent inhibition of steroid sulfatase activity by 3-O-sulfamate 17alpha-benzyl(or 4'-tert-butylbenzyl)estra-1,3,5(10)-trienes: combination of two substituents at positions C3 and c17alpha of estradiol.

Steroid sulfates are precursors of hormones that stimulate androgen- and estrogen-dependent cancers. Thus, steroid sulfatase, the enzyme that catalyzes conversion of DHEAS and E1S to the corresponding unconjugated steroids DHEA and E1, appears to be one of the key enzymes regulating the level of active androgenic and estrogenic steroids. Since 17alpha-substituted benzylestradiols and 3-O-sulfamate estrone (EMATE) represent two families of steroid sulfatase inhibitors that probably act through different mechanisms, we synthesized compounds 3-O-sulfamate 17alpha-benzylestradiol (4) and 3-O-sulfamate 17alpha-(tert-butylbenzyl)estradiol (5) that contain two kinds of substituents on the same molecule. In our enzymatic assay using a homogenate of human embryonal (293) cells transfected with steroid sulfatase, compounds 4 and 5 were found to be more potent inhibitors than already known steroid sulfatase inhibitors that have only a C17alpha-substituent or only a C3-sulfamate group (EMATE). The IC50 values of 4 and 5 were, respectively, 0.39 and 0.15 nM for the transformation of E1S to E1 and 4.1 and 1.4 nM for the transformation of DHEAS to DHEA. Compound 5 inhibited the steroid sulfatase activity in intact transfected (293) cell culture assays by inactivating the enzyme activity. Compound 5 also inactivates the steroid sulfatase activity at lower concentration than EMATE in microsomes of transfected (293) cells. In this assay, an excess of natural substrate E1S protects enzyme against inactivation by 5 or EMATE. Furthermore, the unsulfamoylated analogue of 5, compound 3, did not inactivate the steroid sulfatase.