Protein-reactive metabolites of carbamazepine in mouse liver microsomes

The character of reactive metabolites formed from carbamazepine (CBZ) was sought in incubations of [14C]CBZ in hepatic microsomes prepared from adult female mice of a strain (SWV/Fnn) susceptible to CBZ-induced teratogenicity. The formation of radio-labeled protein adducts was used as an index of reactive metabolite exposure. A dependence on cytochrome P450 was shown by a requirement for NADPH and inhibition by carbon monoxide, 1-aminobenzotriazole, piperonyl butoxide, and stiripentol. The addition of ascorbic acid, caffeic acid, N-acetylcysteine, and glutathione decreased the rate of binding of the radiolabel from [14C]CBZ to microsomal protein by more than 50%. The addition of glutathione transferases diminished protein adduct formation beyond that seen with glutathione alone. Evidence for the formation of an arene oxide was sought through the use of inhibitors of epoxide hydrolases, including cyclohexene oxide, chalcone oxides (with the addition of cytosol as appropriate), and by the addition of recombinant human soluble and microsomal epoxide hydrolases and recombinant rat microsomal epoxide hydrolase. The microsomal epoxide hydrolases decreased the velocity of 14C-labeled protein adduct formation by approximately 23%, whereas inhibitors had no effect, most likely because of the low native activity of microsomal epoxide hydrolase in mice. Both DT-diaphorase and catechol-O-methyltransferase diminished 14C-labeled protein adduct formation by 54% and 45%, respectively. The data suggest that the major reactive metabolites formed from CBZ by adult female SWV/Fnn liver microsomes are quinones and arene oxides.     

Severe anoxia with and without concomitant brain atrophy and neuropsychological impairments

Significant anoxia may cause a variety of neuropathologic changes as well as cognitive deficits. We have recently seen 3 patients who have suffered severe anoxic episodes all with initial Glasgow Coma Scores (GCS) of 3 with sustained coma for 10-14 d. All 3 patients had extended hospitalizations and rehabilitation therapy. A neuropsychological test battery was administered and volumetric analyses of MRI scans were carried out in each case at least 6 mo postinjury. Two of the patients display distinct residual cognitive and neuropathologic changes while 1 patient made a remarkable recovery without evidence of significant morphological abnormality. These three cases demonstrate, that even with similar admission GCS, the outcome is variable and the degree of neuropsychological impairment appears to match the degree of morphologic abnormalities demonstrated by quantitative MR image analysis. An important finding of this study is that even though subjects with an anoxic insult exhibit severe cognitive and memory impairments along with concomitant morphologic changes, their attention/concentration abilities appear to be preserved. MR morphometry provides an excellent means by which neural structural changes can be quantified and compared to neuropsychological and behavioral outcomes.     

Long-lived and transferable tumor immunity in mice after targeted interleukin-2 therapy

A major goal of tumor immunotherapy is the induction of tumor-specific T cell responses that are effective in eradicating disseminated tumor, as well as mounting a persistent tumor-protective immunity. We demonstrate here that a genetically engineered fusion protein consisting of human/mouse chimeric anti-ganglioside GD2 antibody and human interleukin-2 is able to induce eradication of established B78-D14 melanoma metastases in immunocompetent syngeneic C57BL/6J mice. This therapeutic effect is mediated by host immune cells, particularly CD8+ T cells and is associated with the induction of a long-lived immunity preventing tumor growth in the majority of animals when challenged up to four months later with B78-D14 cells. This effect was tumor-specific, since no cross-protection against syngeneic, ganglioside GD2+ EL-4 thymoma cells was observed. Furthermore, this tumor-specific protection can be transmitted horizontally to naive, syngeneic SCID mice by passive transfer of CD8+ T lymphocytes derived from immune animals. These results suggest that antibody-targeted delivery of cytokines provides a means to elicit effective immune responses against established tumors in the immunotherapy of neoplastic disease.     

Time-dependent aspects of osmolyte changes in rat kidney, urine, blood and lens with sorbinil and galactose feeding

Sorbitol plus myo-inositol, betaine and glycerophosphorylcholine (GPC) are cellular osmolytes in the mammalian renal medulla. Galactosemia and hyperglycemia can cause excessive levels of galactitol or sorbitol in several organs via aldose reductase (AR) catalysis. AR inhibitors can reduce these polyols. To examine osmolyte responses to polyol perturbations, male Wistar rats were fed normal diet, the AR inhibitor sorbinil (at 40 mg/kg/d), 25% galactose, or a combination, for 10, 21 and 42 days. All animals at 21 days had higher apparent renal AR activity than at 10 or 42 days, possibly providing resistance to sorbinil. Sorbinil feeding alone tended to increase urinary, plasma and renal urea levels. It reduced AR activity and sorbitol contents in renal inner medulla, though less so at 21 days; other renal osmolytes, especially betaine, were elevated. Galactose feeding caused little change in renal AR activity, and resulted in high galactose and galactitol contents in renal medulla, urine, blood and lens (and higher renal Na+ contents at 10 days). Renal sorbitol, inositol and GPC decreased, while betaine contents trended higher at all times. Sorbinilgalactose feeding reduced renal AR activities and galactitol contents (again less so at 21 days), urine, blood and lens galactitol, and further reduced renal sorbitol contents. At 10 and 21 days it tended to raise renal betaine more, and restore inositol (but not GPC) contents to control levels. At 42 days it reduced renal and urinary Na+ and galactose, and decreased renal betaine to control levels. Under most conditions, total renal (non-urea) organic osmolyte contents (presumed to be mostly intracellular) and Na+ plus galactose contents (presumed mostly extracellular) changed together such that cell volumes may have been maintained. The exception was 10 days on galactose, where total osmolytes appeared too low. In galactose-fed animals, urine/plasma ratios suggest some renal galactitol efflux, and cellular galactitol probably helps maintain osmotic balance rather than cause swelling.     

The fluoride content of enamel as a diagnostic aid in fluorosis

This study was undertaken to compare the fluoride content ([F]) of sound and hypoplastic enamel of dogs' teeth for use as a diagnostic aid for fluorosis. Enamel biopsies (0.5N HClO4; 15 seconds; 3.143 mm2) were conducted on macroscopically sound areas of the middle buccal surfaces of the right upper canine teeth. The [F], and the calcium concentrations of the etching solutions were determined using the potentiometric analytical method and the flame spectrophotometer respectively. Depth of etch (DOE) was calculated. The results of the study showed that the higher [F] in the hypoplastic enamel when compared to that of sound enamel (p > 0.05), was more a result than a cause of the hypoplasia. In this study, the [F] of the enamel was used successfully to exclude the possibility of fluorosis.     

A fatal case of intrathoracic cuterebriasis in a cat

Isolates of Plasmodium falciparum commonly undergo a large, subtelomeric deletion of the right end of chromosome 9 during in-vitro cultivation. This deletion is usually accompanied by loss of ability to cytoadhere to melanoma cells, loss of a var-gene product from the red-cell surface and a reduction in gametocyte production. However, cytoadherence is stable in the isolate ItG2, remaining after many generations in culture. Deletions in all the non-cytoadherent clones examined have breakpoints within or delete a novel open-reading frame, called the breakpoint open-reading frame (BPORF), that is a unique sequence in the genome. In ItG2, surprisingly, BPORF has been removed by a 15-kb deletion, internal in chromosome 9. These results indicate mechanisms to explain why the deletion of chromosome 9 occurs so frequently and why cytoadherence is stable in ItG2.     

Artificial cornea: surface modification of silicone rubber membrane by graft polymerization of pHEMA via glow discharge

A method for producing various surfaces of silicone rubber membrane (SR) was developed in this study by grafting various amounts of poly(2-hydroxy ethyl methacrylate) (pHEMA) onto SR by plasma-induced grafted polymerization (PIP) as a homobifunctional membrane. The elemental composition and different carbon bindings on the surface of SR were examined by electron spectroscopy for chemical analysis with the amount of O1s/C1s being approximately 0.7 at 1 min, 60 W, 200 mTorr of Ar-plasma treatment. The peroxide group introduced on SR was measured via 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the amount of 6.85 x 10(-8) mol cm-2 reached optimum value at 1 min of Ar-plasma treatment. After Ar-plasma treated SR, the peroxide group (33D peak) was introduced on the surface of SR by negative spectra of secondary ion mass spectroscopy analysis, whereas ester groups (72D peak) were observed for pHEMA-grafted SR. For the in vitro test, the influence of various surfaces of SR on attachment and growth of rabbit corneal epithelial cells (CEC) was studied by cell culture assay. These results indicated that 56-150 micrograms cm-2 of pHEMA grafted onto SR were suitable values for attachment and growth of CEC. On the contrary, the large grafted amounts (500-1650 micrograms cm-2) of pHEMA on SR were insufficient for attachment and growth of CEC. For the in vivo test, the migration of CEC from host cornea to implant was investigated by slit lamp microscopy. The experimental results indicated that SRs grafted with pHEMA were completely covered with CEC 3 weeks after implantation of the membranes into the host cornea. These results provide a valuable reference for developing an artificial cornea.     

Laparoscopic port site recurrences in oncologic surgery--a review

The aim of this paper was to review the world's literature regarding port site recurrences. A Medline search was performed for all port site recurrences published in the literature. These reports were analysed and port site recurrences studied to determine initial stage of cancers, time to recurrence and whether the port site was an isolated site of recurrence or part of widespread intra-abdominal disease. The possible aetiologies were similarly reviewed and several recent basic science reports assessed. To date, 93 port site recurrences have been published. These have occurred with colorectal cancers as well as ovarian, gastric, pancreatic and other malignancies. Often, these recurrences are isolated and most standard means of prevention of cell dissemination may not prevent their occurrence. Possible mechanisms include aerosolisation of tumour cells, exfoliation, and changes in immune function. Port site recurrences continue to be reported. Their aetiology is unclear but the occurrence is of concern and requires continued scrutiny for laparoscopic oncologic surgery.     

The effect of trauma on the ocular penetration of intravenous ciprofloxacin

PURPOSE: To study the intraocular pharmacokinetics of intravenously administered ciprofloxacin following eye trauma. METHODS: Twenty-three New Zealand albino rabbits and 12 Yorkshire pigs each received a surgically induced scleral injury to the right eye. Following repair, each rabbit received a single 30-mg intravenous infusion of ciprofloxacin. Each pig received either two 200-mg doses or two 400-mg doses of intravenous ciprofloxacin given 12 hours apart. Vitreous and serum samples were harvested at 0.5, 1, 4, 6, and 12 hours after antibiotic administration in rabbits and 1 hour after the second dose in pigs. Bioassays for ciprofloxacin were performed on each sample, and results were statistically compared by t test. The untraumatized left eye in each animal served as a control. RESULTS: The mean vitreous concentration of ciprofloxacin in traumatized rabbit eyes was 0.37 microgram/ml. This level was sustained above levels in control eyes (0.18 microgram/ml) for at least 4 hours following antibiotic administration. In control eyes, intravitreal levels peaked at 1 hour. Mean vitreous concentrations +/- SD in traumatized pig eyes were 0.091 +/- 0.017 microgram/ml in swine that had received 200-mg doses of ciprofloxacin vs 0.312 +/- 0.153 microgram/ml in swine that had received 400-mg doses (P = .02). Mean vitreous concentrations of ciprofloxacin in control eyes were not affected by increasing dosage. CONCLUSION: In both animal models, experimental surgical trauma increased intravitreal ciprofloxacin delivery. In addition, systemically administered ciprofloxacin achieved intravitreous levels exceeding minimum inhibitory concentrations for common ocular pathogens, suggesting a role for ciprofloxacin in the prophylaxis of posttraumatic endophthalmitis.