After infection with Plasmodium chabaudi, C57BL/10 mice produced significant amounts of serum IFN-gamma, developed a low level of parasitemia and survived the infection. Production of IFN-gamma was also obvious when spleen cells of the infected mice were stimulated with the parasite antigen contained in an erythrocyte lysate in vitro. Depletion of CD4+ T cells abrogated production of IFN-gamma, leading to loss of resistance to the infection. The CD4+ T cells/IFN-gamma-dependent resistance of the C57BL/10 mice against P. chabaudi was applied to assess immunotoxicological effect of dexamethasone (DEX). Administration of a high dose (0.75 mg/kg) resulted in loss of the splenic cellularity, remarkable decrease in serum IFN-gamma production, increased level of parasitemia, and eventual death of the infected mice. In contrast, DEX at a low dose (0.02 mg/kg) induced no alternation in the in vivo host immune activity and the mice survived the infection. However, when spleen cells were obtained from the infected mice administered the low dose of DEX and stimulated in vitro with the parasite antigen, a significantly decreased level of IFN-gamma was demonstrated with compared to control mice. These findings demonstrate that the in vitro production of IFN-gamma by spleen cells from P. chabaudi-resistant C57BL/10 mice was more sensitive to the immunosuppressive effect of in vivo administration of DEX. This ex vivo assay might provide a method for evaluation of drug-induced immunotoxicity at a higher sensitivity than the conventional host resistant assays such as comparison of severity of disease or time to death.

Animals↗

PubMedDate not supplied

Development of an implantable artificial anal sphincter by the use of the shape memory alloy.

In this study, we developed and assessed an artificial anal sphincter driven by an shape memory alloy actuator (AS-SMA). The performance characteristics of the device were analyzed with a measurement system. Assessment showed that the AS-SMA could generate a pressure of 55 mm Hg at an atmospheric temperature of 36 degrees C, and displacement of the SMA actuator was 7.5 mm when the temperature of the SMA plate was 55 degrees C. To evaluate opening and closing, we studied a piglet colostomy model, in which the AS-SMA was implanted around the colostomy in the extraperitoneal space. Flow control tests using living porcine intestine revealed that the AS-SMA could maintain fecal continence against an intestinal pressure of 75 mm Hg. The high pressure zone corresponding to the location of the device was demonstrated in a manometric examination. For 6 days after surgery, we activated the AS-SMA twice a day and observed the bowel movements. The animal experiment indicated that the AS-SMA is able to control the bowel movements of patients with fecal incontinence if several problems, such as burning of tissue around the device and compression injury of the intestine, are resolved.

Alloys↗

PubMedDate not supplied

Differential responses of canine myosin ATPase activity and tissue gases in the pressure-overloaded ventricle dependent upon degree of obstruction: mild versus severe pulmonic and aortic stenosis.

Mild pulmonic stenosis, induced in dogs by banding the pulmonary artery, elevated right ventricular peak systolic pressure to 60% above the control and elevated right ventricular K+- and Ca2+- activated myosin ATPase activities. In contrast, severe pulmonic stenosis, which elevated right ventricular peak systolic pressure to 300% above the control, did not produce an increase in myosin enzymatic ATPase Vmax values but caused a decrease in myosin activity. Mild aortic stenosis, induced by banding the ascending aorta, forcing a transaortic pressure gradient of 25 mm Hg, caused an elevation in left ventricular muosin ATPase, whereas severe aortic banding, brought about by creating a transaortic pressure gradient of 55 mm Hg, never caused an elevation in left ventricular myosin enzymatic Vmax values, but, like severe pulmonic banding, caused a decrease in K+- and Ca2+- activated myosin activities. Normal left ventricular myosin Vmax values in mumol of PO4/mg-min at 37 degrees C were: K+ = 2.84 +/- 0.22, and Ca2+ = 0.97 +/- 0.14. For right ventricular myosin they were: K+ = 2.15 +/- 0.16, and Ca2+ =0.74 +/- 0.10. Analyses of tissue gases, based on mass spectrometry data, showed that the hypertrophied ventricles had an elevated tissue pCO2 and an elevation in the cGMP/cAMP ratio.

Adenosine Triphosphatases↗

PubMedDate not supplied

Intra-arterial infusion chemotherapy on unresectable hepatocellular carcinoma under occlusion of hepatic arterial flow.

Intra-arterial infusion chemotherapy (IAIC) by occluding hepatic arterial flow augments intrahepatic drug concentrations, resulting in response rates higher than those with conventional infusion methods. We recently developed an intra-hepatic artery catheter and device attached with an implantable double-lumen reservoir that can be used for repeated IAIC in outpatient clinics. Eight patients with unresectable hepatocellular carcinoma were treated by infusion of anticancer drugs using this method. The catheter was inserted into the hepatic artery under laparotomy. The occlusion balloon was attached to the common hepatic artery, and catheters were connected to the subcutaneous double-lumen reservoir. Approximately 0.5 ml of distilled water was injected through the one port of the double-lumen reservoir to inflate the balloon, which compressed the artery within the cylinder-like occluder. 4'-O-tetrahydropyranyladriamycin (THP-ADM) was used as the anticancer agent, and two patients received combined administration with carboplatin. Three to seven repeated infusions were possible without any severe side effects. This treatment was also easy to perform in the outpatient clinic. Six of the eight patients survived for more than 2 years, an improvement over the survival rates obtained in a previous conventional IAIC group. We conclude that IAIC with THP-ADM for unresectable hepatocellular carcinoma under occluding blood flow using our device is more convenient and more effective than other available methods.

Aged↗

PubMedDate not supplied

Water jet scalpel for liver resection in hepatocellular carcinoma with or without cirrhosis.

Patients with hepatocellular carcinoma were subjected to hepatic resection by using a water jet scalpel which is a device developed recently. Seventy-two patients who underwent hepatic resection were divided into two groups: group A included patients with HCC associated with liver cirrhosis and group B included patients without cirrhosis. Patient characteristics and liver function tests did not differ significantly between the groups. Resected a specimens weighed lighter in group A than in group B. No significant difference in total blood loss, time of operation and postoperative complications were noted. Physiologic saline employed in the machine to create a fine jet stream was projected through the nozzle on the liver at a pressure of 15-20 kg/cm2. The parenchyma of the cirrhotic liver was divided but the intrahepatic vessels were spared. It was therefore concluded that hepatic resection by water jet is safe and useful in case of HCC associated with cirrhosis of the liver.

Blood Loss, Surgical↗