Pressure-induced skin lesions in pigs: reperfusion injury and the effects of vitamin E.

The pathogenesis of the development of pressure ulcers is still unclear. The aim of this study was to investigate the role of ischaemia and reperfusion in pressure-induced tissue necrosis in the trochanteric region in pigs. Pressure application was achieved with a newly developed computer-controlled pressure device. Histological examination showed damage in the subcutis and muscle tissue comparable with inflammation, extending in a vascular pattern beyond the area of pressure application. Electron-microscopic studies revealed neutrophil adherence to the capillary endothelium, which showed signs of injury. These observations were manifest two hours after the cessation of pressure. Pre-treatment with 500 mg vitamin E per day resulted in significantly less tissue damage compared with untreated animals. Pressure alone caused a significant decrease in reduced glutathione and total glutathione, suggesting oxidative stress. After pressure release there was a significant increase in hydrogen peroxide concentration, suggesting a decreased antioxidant protection. After pre-treatment with vitamin E, however, there was no increase of hydrogen peroxide. It is concluded that the early signs of necrosis after pressure application are concordant with typical ischaemia-reperfusion damage and this can be prevented in part by treatment with vitamin E. Prophylactic administration of vitamin E may influence the occurrence of pressure ulcers in humans undergoing elective surgery.

Intrahepatic interleukin-2 with chemotherapy for unresectable liver metastases: a randomized multicenter trial.

BACKGROUND/AIMS: A pilot study of Interleukin-2 (IL-2) with chemotherapy for unresectable colorectal liver metastases revealed a favorable response rate (76%). This prospective, randomized, multicenter study was conducted to evaluate the efficacy of this treatment protocol. METHODOLOGY: Over a period of 32 months, 46 patients with unresectable liver metastases were randomly assigned to 1 of 3 treatment groups: group A: chemotherapy alone, group B: chemotherapy plus high-dose, intermittent IL-2 (2.1 x 10(6) U twice weekly) or group C: chemotherapy plus low-dose, continuous IL-2 (7 x 10(5) U daily). Treatment continued for 4 weeks in the hospital and on an outpatient basis according to the clinical response. No crossover between treatment arms was permitted. RESULTS: IL-2 combined with chemotherapy produced a higher complete and partial response rate of 40% in group A, 60% in group B, and 78% in group C. Toxicity related to IL-2 included fever, chills, malaise, and eosinophilia. CONCLUSIONS: Hepatic arterial infusion of chemotherapy plus IL-2 resulted in an increased tumor response when compared with chemotherapy alone. To confirm the efficacy of this treatment protocol, we have started a large-scale, randomized, multi-institution trial.

Electrically stimulated free-flap graciloplasty for urinary sphincter reconstruction: a new surgical procedure.

In electrically stimulated (dynamic) graciloplasty for urinary incontinence, the gracilis muscle is transposed into the pelvis, and the distal part is used to reconstruct a neosphincter. Clinical outcomes using this technique have been disappointing due to stricture of the urethra caused by ischemia in the distal part of the gracilis and limited gracilis length available for neosphincter construction. Furthermore, the urethra is twisted by the contracting gracilis, rather than circumferentially squeezed. The purpose of the present study was to test the anatomical and functional feasibility of a new surgical approach to reconstruct a urinary sphincter, using the gracilis muscle as a free flap. In 12 human cadavers, the anatomical feasibility for creating a neosphincter by using the gracilis free flap was determined. In all cases, transfer of the gracilis muscle into the pelvis as a free flap (with the nerve intact) was feasible, and ample muscle was available to construct a neosphincter around the bladder neck. Gracilis neosphincter function was studied in seven dogs. The left gracilis muscle was subjected to transfer into the pelvis as an innervated free flap to create a neosphincter around the urethra. The right (control) gracilis muscle was lifted as a single pedicle flap, remained in situ, and was wrapped around a stent to mimic the urethra. Function (expressed as peak pressure generation and fatigue rate) and surface perfusion were determined for all gracilis muscles. In each dog, both sides were compared using the paired Student's t test for statistical analysis, and no significant difference was measured for the two groups. In conclusion, an innervated gracilis free flap can be used to create a neosphincter around the bladder neck. In an acute study in dogs, function and perfusion of the innervated gracilis free flap are not compromised.

[Clinical evaluation of intra-arterial infusion of hyperthermo-chemotherapy in gastric cancer].

We performed intra-arterial infusion hyperthermochemotherapy by retaining an intra-arterial reservoir in 17 lesions of 12 patients with non-resectable, metastatic or recurrent gastric cancers. The 12 patients consisted of one with a primary gastric cancer lesion, 6 with a solitary gastric cancer lesion metastasizing to the liver, 4 with gastric cancer accompanied by hepatic metastasis, lymph node metastasis or local recurrence, and one with a gastric cancer lesion metastasizing to Douglas' pouch. A catheter was retained in the hepatic artery of all 6 patients with a solitary gastric cancer lesion metastasizing to the liver, and a catheter was retained in the aorta of the patient with a primary lesion, 3 of the 4 patients with two or more metastatic lesions, and the patient with a lesion metastasizing to Douglas' pouch. The duration of each hyperthermia session was 50 minutes, and one or two sessions were performed within a week. One course consisting of 5 or 6 sessions was repeated. Antineoplastic drugs such as MMC, 5-FU, ADR, epi-ADR, CDDP and VP-16 were injected in bolus form or administered serially through the reservoir. Nine of the 12 patients had polypharmacy. One to 3 courses or 4 to 20 sessions at maximum (average 9.8 sessions) were given. The rate of efficacy of intra-arterial infusion hyperthermochemotherapy was 44% for hepatic metastasis and 25% for lymph node metastasis. The local recurrent lesions, the lesion metastasizing to Douglas' pouch and the primary lesion did not respond to therapy.

Effects of zirconia addition on fracture toughness and bending strength of dental porcelains.

Zirconia dispersed composite porcelains with glass and aluminous porcelain as matrix were prepared as models of dental porcelains. The bending strength and fracture toughness of the composite porcelains were examined. The bending strength and fracture toughness of composite porcelains containing 50 wt% zirconia were 20 to 80% greater than in glass alone. However, bending strength and fracture toughness decreased upon the addition of zirconia at more than 50 wt%. Moreover, in the case of aluminous porcelain as matrix, fracture toughness increased to a maximum value of 2.6 M Pa.m1/2by addition of 23 wt% zirconia, twice the toughness of glass alone. On the other hand, no increase of bending strength was observed in this case. Deflection and bowing of cracks as well as microcracking effects were related to these increases of mechanical properties in zirconia dispersed composite porcelains.

[Strength and transparency of dental porcelain consisting of high refractive germanate-glass and alumina crystal].

A translucent aluminous porcelain was developed for dentistry. The effects of refractive indexes and sintering behaviors on transparency and strength of the aluminous porcelains consisting of high refractive germanate-glass (Na2O-TiO2-GeO2) and alumina crystal powders were examined. The various germanate-glass specimens with a high refractive index were made by fusion at about 1,300 degrees C. The refractive indexes of fused Na2O-TiO2-GeO2 glass specimens were 1.64-1.76, heightened with an increasing TiO2 content. The sintered aluminous porcelains were made from the mixed compacts consisting of 80 wt% germanate-glass and 20 wt% alumina at the densification temperature of 580-820 degrees C. Sintered aluminous porcelains prepared with high refractive germante-glass had a high transparency compared with the other aluminous porcelains, with almost the same transparency as a commercial feldspathic porcelain (body). Aluminous porcelains had lower transparency with different refractive index due to generation of crystals following the crystallization of glass matrix than that without crystallizing property. Bending strength value was 120 MPa, which is similar to that for the glass-alumina ceramics with the same content of alumina volume as germanate-glass aluminous porcelains. Non-crystallized aluminous porcelain had a higher strength compared with the crystallized one.

[Studies on sintering of dental porcelain. (Part 1) Binary system sintering of alumina and low fusing frit (author's transl)].

Dental porcelains were made from frit and glass powder with electro fused alumina powder addition in the range from 20 to 60 wt% using sintering method at the temperature from 500 degree C to 1 000 degree C, and the effects of alumina content and firing temperature on firing processes of sintered composite were investigated. Shrinkage curves of the powder compacts varied with kind of frit and content of alumina. Particulary, powder compact with alumina addition in the range from 50 to 55% was found to have a remarkable influence for extention of firing temperature range. The densification of the powder compacts was considered to be accelerated by the dissolution of a small a mount of alumina particle into the frit and glass above 900 degree C. Expansion coefficient value of sintered composite of alumina and Pyrex glass powder gradually increased with increase of alumina content. Inversely, expansion coefficient of soda-lime-silica glass showed the minimum value at 40 wt% alumina content and then had a tendency of slight increases with increase of alumina content.