Slow, spontaneous degradation of lansoprazole, omeprazole and pantoprazole tablets: isolation and structural characterization of the toxic antioxidants 3H-benzimidazole-2-thiones

The spontaneous degradation of lansoprazole, omeprazole and pantoprazole tablets upon long-term and forced storage conditions was determined by high performance liquid chromatography (HPLC). The more abundant products could be isolated by liquid chromatography and their molecular weights determined by Mass Spectrometry (MS). Their structures, established according to their spectroscopic data, were compared to those of either the literature or of authentic samples. Thus lansoprazole led mainly to a mixture of 3H-benzimidazole-2-thione (2a) and 3H-benzimidazole-2-one (2c), omeprazole mainly to a mixture of 5-methoxy-3H-benzimidazole-2-thione (1a) and 2-hydroxymethyl-3, 5-dimethyl-4-methoxypyridine (1b), and pantoprazole, to 5-difluoromethoxy-3H-benzimidazole-2-thione (3a) and 2-hydroxymethyl-3, 4-dimethoxypyridine (3b). Although some of the degradation products had already been observed under different conditions, the detection of benzimidazole-2-thiones is unprecedented and their involvement as possible physiological, yet toxic antioxidants must be emphasized. Plausible, unified mechanisms for the formation of the different degradation products observed herein and in previous papers from the literature are suggested.

Effect of basic fibroblast growth factor on insulin secretion from microencapsulated pancreatic islets: an in vitro study

Microencapsulation of pancreatic islets represents a potentially effective method to prevent graft rejection in allotransplantation or xenotransplantation without the need of immunosuppression. Adequate insulin secretion and glucose responsiveness of microencapsulated pancreatic islets has been regarded as a prerequisite for successful transplantation. The microencapsulated pancreatic islets were respectively cultured in bFGF+ RPMI-1640 medium (bFGF+) or bFGF- RPMI-1640 medium (bFGF-) for 21 days. The functional activities of microencapsulated pancreatic islets were assessed by measuring basal insulin secretion and stimulated insulin release at different time points. The results revealed that microencapsulated pancreatic islets in the presence of bFGF demonstrated an increase in basal insulin secretion. Furthermore, microencapsulated pancreatic islets in the presence of bFGF demonstrated a marked stimulated insulin release and relative stability of stimulation indices (SI). The results in the perifusion study showed that microencapsulated pancreatic islets in the presence of bFGF maintained good glucose responsiveness over the course of culture period as well. These results indicate that bFGF has a beneficial effect on insulin secretion from microencapsulated pancreatic islets during in vitro culture. New strategies for preserving and improving function of microencapsulated pancreatic islets prior to transplantation may be developed by application of growth factors or other factors.

Evaluation of insulin secretion of isolated rat islets cultured in extracellular matrix

Islet isolation involves enzymatic digestion of the interstitial matrix and mechanical disruption of the tissue. It is possible that a fundamental change of islet biology resulting from the loss of critical factors required for islet function or survival will occur. Extracellular matrix (ECM) is one of the most important components of the islet microenvironment. Reconstruction of the cell-matrix relationship seems to be effective for improving the loss of differentiated islet structure and function. The purpose of this study was to characterize and compare the effects of collagen gel mixture or Matrigel on beta-cell function and islet cell survival. After isolation by the collagenase digestion technique, rat islets were divided and cultured with various types of collagen gel mixture. They were assessed for their glucose-stimulated insulin secretion and cell viability. Glucose-induced insulin secretion of islets cultured with collagen type I gel or a mixture of collagen type I and IV was improved after 11 days in culture. In conclusion, a type of gel composed of collagen type I and/or type IV as an islet microenvironment is sufficient to maintain glucose responsiveness and may be useful for islet transplantation.

Neutralization of interleukin-1beta in the acute phase of myocardial infarction promotes the progression of left ventricular remodeling

OBJECTIVES

We sought to examine the role of the pro-inflammatory cytokine, interleukin-1-beta (IL-1beta), in the process of left ventricular (LV) remodeling in the early phase after myocardial infarction (MI).

BACKGROUND

Studies have shown that pro-inflammatory cytokines are closely related to the progression of LV remodeling after MI.

METHODS

Mice underwent coronary artery ligation, and the time course of LV remodeling was followed up to 20 weeks. The gene expression level of IL-1beta was examined. In a second set of experiments, the mice underwent coronary artery ligation followed by treatment with anti-IL-1beta antibody (100 microg, intravenously), versus control immunoglobulin G (100 microg, intravenously) immediately after the operation.

RESULTS

Rapid hypertrophy of noninfarcted myocardium was observed by four weeks, and interstitial fibrosis progressed steadily up to 20 weeks. Anti-IL-1beta treatment increased the occurrence of ventricular rupture and suppressed collagen accumulation in the infarct-related area. At four and eight weeks after the operation, total heart weight and LV end-diastolic dimension were significantly greater in the anti-IL-1beta-treated mice than in the other groups. In the infarct-related area, collagen accumulation was suppressed, whereas in the noninfarcted area, pro-collagen gene expression levels, particularly type III, were decreased in the anti-IL-1beta-treated mice.

CONCLUSIONS

Anti-IL-1beta treatment suppressed pro-collagen gene expression and delayed wound healing mechanisms-properties that are likely to lead to progression of LV remodeling. In the acute phase of MI, IL-1beta appears to play a protective role.

5'-deoxy-5-fluorouridine, medroxyprogestrone acetate and mitoxantrone hydrochloride for advanced or recurrent breast cancer

BACKGROUND

In treating advanced or recurrent breast cancer, anthracycline-containing chemotherapy is used for palliation and to maintain quality of life. However, there are several drawbacks including therapeutic failure and cardiotoxicity. We evaluated the efficacy and toxicity of combination chemotherapy with 5'-deoxy-5-fluorouridine (5'-DFUR), medroxyprogestrone acetate (MPA) and mitoxantrone hydrochloride (MIT).

METHODS

Sixteen patients with advanced or recurrent breast cancer were enrolled. Chemotherapy was given in a 28-day cycle, starting with MIT 10 mg/m2 intravenously on day 1, then oral 5'-DFUR 800 mg and MPA 800 mg daily. Two or more cycles were given.

RESULTS

Fifteen patients were assessable for response and toxicity. Thirteen patients had been treated previously with an anthracycline containing regimen and 2 with CMF. There were 2 partial response patients (13.3%) and 1 complete response patient (6.7%). There were 11 patients showing no change (NC) (73.3%), one of whom was a minor responder and 7 with a long period of NC. There was only one with progressive disease patient. The overall response rate was 20.0%. Adverse events occurred in 5 patients (33.3%). Myelosuppression was the most common with 5 patients becoming leukopenic (33.3%). Nausea/vomiting was the second most common side effect, affecting 2 patients (13.3%).

CONCLUSION

Given its high efficacy and preservation of QOL, the combination of MIT, 5'-DFUR and MPA can be a 2nd or 3rd line therapy for advanced or recurrent breast cancer, especially for anthracycline-resistant cases.

Failure to remove autoreactive Vbeta6+ T cells in Mls-1 newborn mice attributed to the delayed development of B cells in the thymus

Clonal deletion of autoreactive T cells in the thymus is one of the major mechanisms for establishing tolerance to self-antigens, and self-reactive T cells bearing Vbeta6 T-cell receptors are usually deleted before their maturation in Mls-1a mice. However, these T cells develop transiently in the neonatal thymus, and migrate to the periphery. In order to understand the mechanisms which permit these potentially auto-toxic T cells to generate, we investigated in vivo the physiological or functional properties of the elements involved, such as neonatal T cells, antigens and antigen-presenting cells (APC). Confirming the previous findings that each of these elements per se is already completed in function in neonates, we investigated the possibility of the absence or immaturity of particular APC with Mls antigens of their own products in the neonatal thymus. In the search for the cellular and histological changes occurring in the newborn thymus, we found that the elimination of Vbeta6+ T cells progressed in parallel with the development of thymic B cells. Involvement of B cells in purging the autoreactive T cells from the newborn thymus was shown by prevention of the deletion of Vbeta6+ T cells after the removal of B cells by the treatment of neonates with anti-immunoglobulin M antibodies. The restricted and stable expression of CD5 on the thymic B cells, but not on the splenic cells, suggests that these B cells are not postnatal immigrants from the periphery. Finally, it is concluded that the deficiency in the deletion of self-reactive T cells in the thymus of Mls-1a neonates is due to the delayed development of B cells.

[Percutaneus cholangiography with the Chiba needle. Results in 220 studies]

The authors employed this new technique of thin needle percutaneous cholangiography in 220 patients with the following results: 99.3% (146/147) success with previous biliary tract dilatation and 79.4% (53/73) success in patients with normal caliber bile ducts. The overall result of 92.7% (204/228) emphasizes that radiological opacification is the best way to study the icteric patient. Only 1.8% of patients with serious complications is less than in other instrumentation methods. By not requiring specialized equipment and being accessible in the majority of hospitals, study cost is reduced. In conclusion, this new technique of percutaneous cholangiography is preferable for accessibility, efficacy, cost and risk in the study of the icteric patient.

Neutrophilic turnover rate in human age groups evaluated by serum lysozyme activity

Serum lysozyme activity was determined in 135 healthy people classified into five different age groups ranging from 20 to 90 years. A turbidometric method with egg-white lysozyme as standard enzyme using the Fragiligraphy for automatic recording of the serum lysozyme was used. The results show a progressive increase in serum lysozyme activity with age. In the oldest age group of 60-90 years, the increase in serum lysozyme was more than that expected for the diminished glomerular filtration rate in old age. Since the serum level of lysozyme can reflect the rate of neutrophilic turnover, it can be assumed that this rate increases above the age of 60.