Adsorption of histones on natural polysaccharides: The potential as agent for multiple organ failure in sepsis

Histones are intracellular proteins that are structural elements of nuclear chromatin and regulate gene transcription. However, the extracellular histones released in response to bacterial challenges have been identified as mediators contributing to endothelial dysfunction, organ failure, and death during sepsis. In the present study, the adsorption of histones as well as plasma proteins (α1-acid glycoprotein (AGP), albumin, and γ-globulin) on alginic acid, pectin, dextran, and chitosan was examined in order to evaluate the potential of natural polysaccharides as therapeutic agents for multiple organ failure in sepsis. Alginic acid and pectin strongly adsorbed histones, whereas the adsorption abilities of dextran and chitosan toward histones were very low or negligible. Among the natural polysaccharides examined, only alginic acid did not adsorb any of the plasma proteins. These results demonstrated that alginic acid strongly adsorbed histones, but not plasma proteins; therefore, it has potential as a candidate drug for the treatment of multiple organ failure in sepsis.

Characteristics of drug release from gel beads formed by hydrolysis of alginic acid into guluronic acid blocks

Alginic acid (Alg) is a natural anionic polysaccharide, which consists of α-L-guluronic acid (G) and β-D-mannuronic acid (M). G-G sequence-rich chain regions, known as G-blocks (GB), are important regions for gelation of Alg using divalent cations. In this study, calcium-induced GB gel beads were prepared, and drug release profiles and degradation properties of the GB gel beads were investigated in aqueous media. The GB gel beads swelled slightly in JP XVI 1st fluid (pH 1.2), and only slight release of sodium diclofenac (DF) from the GB gel beads was observed. Disintegration of the GB gel beads was not observed in the 1st fluid. On the other hand, the GB gel beads disintegrated in JP XVI 2nd fluid (pH 6.8), and the rate of disintegration depended on the concentration of calcium chloride used to prepare the GB gel beads. The DF release profiles of the GB gel beads in the 2nd fluid could be controlled by the concentration of CaCl2 used to prepare the GB gel beads. The initial release profile of DF from GB gel beads was not consistent with the profile of disintegration. According to the Higuchi-plot of the percentage of drug content released against the square root of time, gel disintegration did not affect the release of DF from GB gel beads. It appears that a diffusion-type mechanism was responsible for DF release. We propose that the GB gel bead gel matrix is an effective medium by which to control the release of drug within the gastrointestinal tract.

Development of film dosage form containing allopurinol for prevention and treatment of oral mucositis

Film dosage forms (FDs) containing allopurinol (AP) were prepared using a casting method with water-soluble polysaccharides, such as sodium alginate (ALG), and the release profile of AP from FDs was investigated in limited dissolution medium. Some ALGs were able to form FDs incorporating AP, and the thickness was about 50 μm. All FDs were easy to handle, though the rheological properties varied with ALG species. AP was homogenously present throughout the FDs and was released with disintegration in 10 mL of physiological saline. These results confirmed that FDs are useful for preventing or treating localized problems in the oral cavity, such as mucositis. FDs are also useful for administering drugs to cancer patients receiving chemotherapy and/or radiotherapy.

Antioxidant Activity of β-Glucan

β-Glucans extracted from barley, which mainly contains β-(1,3-1,4)-D-glucan, are used extensively as supplements and food additives due to their wide biologic activities, including a reduction in blood lipid level. In this study, the antioxidant activity of β-glucan was examined to assess potential new benefits associated with β-glucan, because oxidative stress is considered one of the primary causal factors for various diseases and aging. β-Glucan extracted from barley was found to possess significant antioxidant activity. The amount of antioxidant activity was influenced by different physiologic properties (e.g., structure and molecular size) of β-glucan, which varied depending on the source and extraction method used. The antioxidant activity of β-glucan was significantly higher than that of various polymers that are used as food additives. These results indicate that β-glucan has promise as a polymeric excipient for supplement and food additive with antioxidant and other benefits, which may contribute to enhancing health and beauty.

Sustained insulin release with biodegradation of chitosan gel beads prepared by copper ions

Chitosan (CS) gel beads were prepared with chelated copper (II) ions as a vehicle for the delivery of peptide and protein drugs. Insulin, which is a model of peptide and protein drugs, was scarcely released from the CS gel beads in vitro, presumably due to the nature of interactions occurring between insulin, CS and the copper (II) ions. The efficacy of insulin released from the CS gel beads was confirmed by implantation into diabetic mice. A consistent reduction in blood glucose level was observed in vivo due to insulin release as the CS gel beads were degraded. Control over insulin release was achieved by altering the properties of the CS. Thus, CS gel beads are promising as a biocompatible and biodegradable vehicle by which peptide and protein drugs can be delivered.

Preparation of floating alginate gel beads for drug delivery to the gastric mucosa

Alginate gel beads containing ethylcellulose (ALECs) were prepared and investigated with regard to buoyancy, in vitro and in vivo drug release profiles, and drug targeting specificity in the gastric mucosa. When the ethylcellulose (EC) content of ALECs containing metronidazole (MZ) was higher than 3%, the beads floated in all test solutions with a specific gravity of approx. 1.01. ALECs containing 5% EC released MZ gradually and floated throughout the experimental period in simulated gastric juice (pH 1.2), and all of the drug had been released after 90 min. When we orally administered ALECs to guinea pigs, about 85% of the incorporated MZ was released at 1 h. The MZ concentration of the gastric mucosa after administration of ALECs was greater than that observed with administration of MZ solution, despite lower serum concentrations. Furthermore, the similar data were obtained for ALECs with 7% EC. These results suggest that ALECs may become a practical vehicle for delivering drugs to the gastric mucosa.

Therapeutic efficacy of sustained drug release from chitosan gel on local inflammation

The model anti-inflammatory drug prednisolone (PS) was retained in chitosan (CS) gel beads, which were prepared in a 10% aqueous amino acid solution (pH 9.0). Sustained release of PS from the CS gel beads was observed. Carrageenan solution was injected into air pouches (AP), which were prepared subcutaneously on the dorsal surface of mice, in order to induce local inflammation. CS gel beads retaining PS were then implanted into the AP to investigate the therapeutic efficacy of sustained PS release against local inflammation. In vivo PS release from CS gel beads was governed by both diffusion of the drug and degradation of the gel matrix. Sustained drug release by CS gel beads allowed the supply of the minimum effective dose and facilitated prolonged periods of local drug presence. Inflammation indexes were significantly reduced after implantation of CS gel beads when compared with injection of PS suspension. Thus, extension of the duration of drug activity by CS gel beads resulted in improved therapeutic efficacy. These observations indicate that CS gel beads are a promising biocompatible and biodegradable vehicle for treatment of local inflammation.

Properties of an Alginate Gel Bead Containing a Chitosan-Drug Salt

A calcium-induced alginate gel bead (Alg-CS) containing chitosan (CS) and 2-(4-chlorophenoxy)-2-methylpropionic acid (CMP) was prepared. We then investigated (a) CMP release from Alg-CS, and (b) uptake of bile acid into the Alg-CS, within the gastrointestinal tract. Dried Alg-CS gradually swelled in taurocholate solution, while releasing CMP and taking up bile acid. The amount of bile acid taken up into the Alg-CS increased incrementally according to the degree of deacetylation of CS. Furthermore, the molecular weight of CS also affected the properties of the Alg-CS. An approximately linear relationship was observed between CMP release and bile acid uptake of Alg-CS.

Effects of natural polysaccharide addition on drug release from calcium-induced alginate gel beads

Calcium-induced alginate gel beads (Alg-Ca) containing various polysaccharides, including an alginate hydrolysate, were prepared and the drug release profiles were investigated. Hydrocortisone (HC) was gradually released from Alg-Ca into the mimic gastric fluid, while in intestinal fluid, it was quickly released with the dissolution of Alg-Ca. However, with Alg-Ca containing 5% chitin (CT), dissolution of Alg-Ca was not observed, and release of HC showed apparent zero-order kinetics. Furthermore, addition of the alginate hydrolysate altered the HC-release profile for Alg-Ca.

Retention and release behavior of insulin in chitosan gel beads

Chitosan (CS) gel beads were prepared in a 10% (w/v) aqueous amino acid solution (pH 9.0) as a vehicle for delivering peptide and protein drugs. CS gel beads with a weight-average molecular weight of (16-280) x 10(4) were employed in this study. Preparation of the CS gel beads was affected by properties such as molecular weight and degree of deacetylation. Insulin, which is commonly used to assess protein drug delivery, was retained in the CS gel beads. Drug release from the CS gel beads was governed by diffusion of drug from the gel matrix. Sustained release of insulin from the CS gel beads was observed, despite the fact that insulin is a comparatively water-soluble drug. because insulin formed a complex with CS. Modification of the CS gel matrix by chondroitin sulfate inhibited release of insulin from the gel beads. CS gel beads were implanted into air pouches prepared subcutaneously on the dorsal surface of diabetic mice in order to investigate the efficacy of insulin retained in the CS beads. Blood glucose levels were found to be reduced after implantation of CS gel beads retaining insulin. CS gel beads may possibly improve the stability and control of insulin release. These observations indicate that CS beads are a promising biocompatible and biodegradable vehicle for peptide and protein delivery.

Effect of chondroitin sulfate on the biodegradation and drug release of chitosan gel beads in subcutaneous air pouches of mice

Chitosan (CS) gel beads were prepared in 10% amino acid solution (pH 9) and modified by forming an electrostatic complex between the amino group of CS and the carboxyl group of chondroitin sulfate (Cho). Modification of the CS gel matrix by Cho inhibited the in vitro release of prednisolone (PS) from the gel beads. CS gel beads modified by Cho (CS-Cho) were implanted into air pouches (AP) prepared subcutaneously on the dorsal surfaces of mice. No inflammatory response was observed. The in vivo release of PS from CS-Cho gel beads and their biodegradation in the AP was slower than beads without Cho treatment. After 28 days of implantation, CS-Cho gel beads (deacetylation of CS: 90%) were still detectable, although they had become softer and smaller. Modification of the CS gel matrix by Cho controls the biodegradation of the beads and the release of the drug. This effect makes these beads a promising biocompatible and biodegradable vehicle for sustained drug delivery.

The significance of MMP-1 and MMP-2 in peritoneal disseminated metastasis of gastric cancer

The purpose of this study was to clarify the role of the matrix metalloproteinases (MMPs), collagenase (MMP-1), and gelatinase A (MMP-2), both of which are known to be involved in the development of gastric cancer, in peritoneal dissemination. The concentrations of MMP-1 and MMP-2 in the supernatant of mixed culture simulated peritoneal dissemination were measured in vitro with mesothelial cells and cancer cells using an enzyme-linked immunosorbent assay. The concentration of MMP-1 increased significantly after the contact culture was mixed with these two cells, in comparison with the non-contact mixed culture or the mesothelial cell culture alone. These results demonstrate that the production of MMP-1 derived from mesothelial cells was increased by contact with cancer cells. To clarify the effect of MMP-1 and MMP-2 on gastric cancer invasion, an invasion assay using matrigel was performed. After treatment with anti-MMP-1 monoclonal antibody (mAb) or anti-MMP-2 mAb, the number of matrigel-penetrating cancer cells was significantly reduced, indicating that MMP-1 and MMP-2 derived from mesothelial cells had a strong reaction to gastric cancer invasion. In conclusion, as MMP-1 showed a paracrine-like action responding to stimulus from cancer cells, it seemed to play an important role in the progression of peritoneal dissemination.

Biodegradation and drug release of chitosan gel beads in subcutaneous air pouches of mice

Chitosan (CS) gel beads were prepared in 10% amino acid solution (pH 9) and implanted into air pouches (AP) prepared subcutaneously on the dorsal surface of mice. No inflammatory response was observed, and degradation of the beads in the AP increased as their degree of deacetylation decreased. Degradation could be altered by changing the nature of the CS or by increasing the CS concentration. The release of prednisolone (PS) in vivo from CS gel beads was similar to the release in vitro. When a suspension of PS was injected into the AP, the PS had almost completely disappeared 24 h after injection. Retention of PS in the AP was not increased by using a viscous CS solution. Alginate (Alg) gel beads, which were not degraded, released PS slowly into the AP over 3d. The in vitro release profile of PS using 1% CS (deacetylation: 70% (7B) and 80% (8B)) and 1.5% CS (deacetylation: 90% (9B)) gel beads was similar to that with Alg gel beads. However, the in vivo release of PS was affected by the degradability of the gel beads. CS7B and 8B (1%) gel beads had released PS into the AP earlier than 3 d according to their rate of degradation. CS9B (1.5%) gel beads were not degraded after 3 d and went on to release PS into the AP for 3 d similar to the release profile of Alg gel beads. CS9B (2%) gel beads were also not degraded after 3 d and the release of PS from these beads into the AP was sustained; 76% and 27% of administered PS remained in the gel beads after 1 and 3 d, respectively. Therefore, degradation and drug release of CS gel beads can be controlled by changing the structure of the gel matrix, which appears to make these beads a promising biodegradable vehicle for sustained drug delivery.

The controlled release of a drug from biodegradable chitosan gel beads

Chitosan (CS) forms a gel in solutions with a pH above 12, and the gelation occurs at pH of about 9 in 10% amino acid solutions. In this paper, we investigated the enzymatic degradation and the drug release profile of this novel CS gel beads. The degradability of the CS gel beads was affected by the CS properties, e.g. the degree of deacetylation. The release of prednisolone (PS), as a model drug, from the CS gel beads was sustained significantly compared with the gel prepared with NaOH only. However, the release was not able to be sustained by the increment of NaOH concentration in the solution employed for the preparation of CS gel beads. We also investigated the control of drug release from CS gel beads by application of a complex formed between chondroitin sulfate (Cho) and CS. The release of PS from the CS gel beads treated with Cho was prolonged, and the release pattern was not affected by the treatment time. The time to 50% drug release was about 5 min with PS powder, about 200 min in CS gel beads with 10% glycine (Gly) (pH 9.0), and about 330 min in the CS gel beads with 10% Gly (pH 9.0) treated with Cho. Thus CS gel beads appear promising as a vehicle for sustained drug delivery, and the degradation of CS gel beads may be controlled by the degree of deacetylation of CS.

Preparation and drug retention of biodegradable chitosan gel beads

Chitosan (CS) gel beads containing drug could be prepared in amino acid solutions of pH about 9, despite the requirement for a pH above 12 for gelation in water. This phenomenon was observed not only in amino acid solutions but also in solutions of compounds having amino groups. A solute concentration of more than 10% was required for preparation of gel beads at pH 9. Gelation of the CS beads required about 25 to 40 min, depending on the species of amino acid. Lidocaine hydrochloride (LC) as a model drug was retained in the beads to about 20 to 35% of the theoretical total amount, despite being a water-soluble drug. The release of LC from the CS gel beads was prolonged. The release pattern was not affected by the species of amino acid or CS, or the preparation time.

Lymph node metastasis and lymphadenectomy for carcinoma in the gastric cardia: clinical experience

METHOD AND MATERIALS

To suggest improved guidelines for treating lymphatic spread and to understand the results of extended lymphadenectomy. A total of 141 cases of cardia carcinoma admitted to our hospital during 1980 to 1993 were analyzed.

RESULTS

123 of 141 cases underwent resection. The incidence of mediastinal lymph node involvement rose from 8.7% in cases with 1-2 cm invasion to 52.9% in cases with more than 4 cm invasion into the esophagus. The incidence of abdominal lymph node involvement also rose with increasing esophageal invasion. Paraaortic lymph node metastasis was frequently observed in cases of more than 1 cm esophageal invasion. D4 lymphadenectomy (extended lymphadenectomy) revealed better results for the cases with lymph node involvement (P<0.05). There was no difference in the incidence of postoperative complication or in operative death, between the abdominal approach and the thoracoabdominal approach, or between the D4 lymphadenectomy and D2 lymphadenectomy.

CONCLUSION

Sufficient mediastinal and abdominal lymphadenectomy under a clear wide surgical field achieved through the thoracoabdominal approach appeared to bring better results.

Gastrectomy with combined resection of other organs for carcinoma of the stomach with invasion to adjacent organs: clinical efficacy in a retrospective study

BACKGROUND

Carcinoma of the stomach invading one or more adjacent organs raises serious concerns over en bloc dissection because en bloc resection has an associated high risk and such advanced carcinoma is frequently associated with incurable factors. Thus, it is important to understand the efficacy of gastrectomy combined with other organ resection and to refine the indications for en bloc dissection.

STUDY DESIGN

Seventy-seven patients with carcinoma of the stomach directly invading adjacent organs or structures were analyzed retrospectively to investigate the efficacy of en bloc resection. Forty-one patients underwent gastrectomy combined with resection of one or more invaded organs (combined resection group), while the other 36 patients underwent gastrectomy with palliative abrasion between the primary tumor and the invasion site (noncombined resection group).

RESULTS

The five-year survival rate was 23 percent in the combined resection group and 0 percent in the noncombined resection group (p < .05). The 23 curative cases and 18 noncurative cases in the combined resection group had a survival rate of 41 percent and 0 percent, respectively (p < .05). The survival rate after a single organ resection was 29 percent, and after a multiple organ resection, 0 percent (p < .05). Cases of carcinoma invading either the pancreas or mesocolon had a slightly but not significantly better prognosis. In Borrmann type IV carcinoma there was no difference in survival between the curative and noncurative operation. Cases with P1 dissemination had a better prognosis than those of P2 and P3 dissemination.

CONCLUSIONS

The best indication for an en bloc combined organ resection was an invasion limited to only one other organ, not more than N2, no incurable factor, and any type except Borrmann type IV. Additionally, an en bloc combined resection would be worth trying for any type of gastric carcinoma with not more than P1 dissemination and with no other incurable factor.

Gallstones and gallbladder disorder after gastrectomy for gastric cancer

The incidence of gallbladder diseases, in particular of gallstones, was investigated in 268 cases during follow-up after resection of a gastric cancer. Factors investigated for correlation with any incidence included the extent of gastrectomy, reconstruction, and the degree of lymph node dissection. Moreover, in 20 of these, the contractile function test using a cerulein injection was performed, while in a further 6 cases, a sequential contractile function test with fatty meal was performed. The incidence of gallstones was 10.5% after total gastrectomy, 12.4% after distal gastrectomy. Debris was found in a further 6.7% after total gastrectomy and in 1.2% after distal gastrectomy. There was no difference in the incidence of gallstones among the reconstruction methods. With respect to lymph node dissection, the incidence of gallstone formation was 16.3% after D3 and 8.5% after D2-1. In the contractile function test, although the basal area was significantly larger after D3 than after D2-1, there was no difference in the contractile rate. The sequential contractile function test showed a peak contraction at 15 minutes after feeding with gradual refilling in both those after D3 and those after D2-1.

[Expression of the growth factors (EGF, EGFR, and TGF alpha) and PCNA in superspreading and penetrating types of gastric carcinomas]

Expression of EGF, EGFR, TGF alpha, and PCNA in resected gastric carcinomas (15 cases of superspreading type and 25 cases of penetrating type) was immunohistochemically studied to understand biological features of these two types of gastric carcinomas. EGF, EGFR, and TGF alpha positive cases were preferentially found in the penetrating type rather than in the superspreading type (p < 0.05). Incidence of PCNA high expression cases in the penetrating type was significantly higher than that in superspreading type. Nineteen cases (76%) of the penetrating type and 1 case of the superspreading type (6.7%) were diffusely PCNA (+), and the incidence of in the former type was significantly higher than that of the latter type (p < 0.001). One case of the superspreading type and 13 cases of the penetrating type were either EGF (+) or TGF alpha (+), and EGFR (+), and the incidence in the latter type was significantly higher than that in the former type (p < 0.05), suggesting that growth and invasion of carcinoma cells, especially in the penetrating type, may depend on "autocrine mechanism". Incidence of the growth factors (+) and PCNA (+) cells in classical type of signet ring cells was lower than that in other types of singnet ring cells.

[A case of advanced gastric cancer with liver and lung metastasis effectively treated by combined chemo-immunotherapy of MMC, 5'-DFUR, OK-432]

A sixty-eight-year-old male patient was diagnosed as having inoperable advanced gastric cancer with liver and lung metastasis. The patient was treated by combined chemo-immunotherapy of MMC 10 mg/M, 5'-DFUR 800 mg/day and OK-432 5 KE/2 W. Six months after commencing chemotherapy, CT-scan and upper GI series revealed that metasized liver tumors and stomach lesion were remarkably decreased in size and no cancer cell was confirmed by endoscopic biopsy. Further, the metastatic lung tumor has disappeared on chest X-ray. The patient had been well without any evidence of tumor re-progression for over one year, but from July the liver tumor began to metastasize again and the patient eventually died of liver metastasis on Jan. 1, 1993.