Principal axes and surface fitting methods for three-dimensional image registration

We evaluated the effect of the image acquisition parameters on the accuracy of the principal axes and surface-fitting techniques for three-dimensional image registration. Using two types of phantom objects, MR brain image and a mathematically defined ellipsoid, we simulated pairs of scans with known acquisition parameters, including longitudinal coverage, magnitude of mis-registration, number of sections and section thickness. Both methods are sensitive to the systematic deformation of contours. The principal axes method is also sensitive to incomplete scan coverage and to the x-axis and y-axis misangulation. Both methods are insensitive to the number of sections, section thickness and the number of points per section. Surface fitting performed well without user supervision. There is no need for routine inclusion of the scaling factors as search parameters. The results confirm the feasibility of three-dimensional multimodality registration of brain scans with accuracy 1-2 mm, with surface fitting being the method of choice.     

Phase I/II study of a short course of weekly cisplatin in patients with advanced solid tumours

Twenty-five patients with advanced solid tumours were entered in a phase I/II study of six, weekly cycles of cisplatin. Nineteen patients were chemonaive and six were previously treated. The starting dose was 50 mg m-2 week-1. This dose could be escalated without major toxicity to 70 mg m-2 week-1. At a dose of 80 mg m-2 myelosuppression grade 3 occurred as well as grade 1 nephro- and neurotoxicity. The maximum tolerated dose was 85 mg m-2 with dose limiting thrombocytopenia. Hypertonic saline was effective in preventing nephrotoxicity. Ondansetron was a very effective antiemetic in the first weeks of treatment but its efficacy waned later on. Responses were observed in head and neck cancer, melanoma and mesothelioma. At the dose level of 80 mg m-2 the optimal dose intensity was reached. This schedule will be tested further in phase II studies.     

Dual immunodetection and hybridisation in situ of opsin mRNA and rhodopsin protein in retinal sections

We describe a simple method for combining in situ hybridisation and immunohistochemistry on the same retinal section. The technique was developed using a radiolabelled cDNA probe for opsin and an antibody (ROS1F4) against rhodopsin. This method retains the antigenic sites if immunocytochemistry is performed prior to in situ hybridisation. Opsin mRNA was found in the photoreceptor inner segment with rhodopsin immunolocalised to the photoreceptor outer segments. The technique should be applicable to numerous situations including analysis of the sequence of events in the expression and synthesis of the various opsins during retinal development and degeneration.     

Structural characterization of a new galactofuranose-containing glycolipid antigen of Paracoccidioides brasiliensis

An acidic glycolipid (Band 1), purified from P. brasiliensis by a combination of ion exchange chromatography, HPLC, and HPTLC, was found to be reactive with sera of all patients with paracoccidioidomycosis (PCM). Monosaccharide analysis of Band 1 yielded mannose and galactose in a 2:1 ratio, while mild acid hydrolysis and mild periodate oxidation/NaB3H4 reduction indicated the presence of a terminal galactofuranose. Preliminary analysis of 1H-NMR and MS data suggests that the structure of the glycan is Galf beta 1-->6(Manp alpha 1-->3)Manp beta 1-->2Ins (Ins = myo-inositol). Removal of the galacto-furanose decreased by 60-80% the reactivity of sera from PCM patients with Band 1, suggesting that this residue is immunodominant. With the presumed absence of galactofuranose in mammalian hosts, compounds containing this residue may be useful targets for therapy of several parasitic and fungal diseases.     

The pattern of inflammation in rat sepsis due to enterotoxin-producing Staphylococcus aureus: a comparison with ischemia-reperfusion injury

Sepsis and trauma have similarities in their immunopathologic profiles. Both conditions can result in multi-system organ failure which is sometimes associated with cytokine generation and inflammatory cell activation. Furthermore, decreases in peripheral blood monocyte expression of HLA-DR have been noted in both human sepsis and trauma. However, the magnitude, onset, and time course of such stimuli are often difficult to ascertain in human studies. Thus, to study a more detailed in vivo immunologic profile in these conditions, rat models were employed. Our aim was to describe and analyze cytokine and peripheral blood immunophenotype patterns in bacterially induced rat sepsis and to compare this to rat ischemia-reperfusion injury. Sprague-Dawley rats underwent either bacterial injection with enterotoxin producing Staphylococcus aureus or hind limb ischemia/ reperfusion. Two bacterial doses which were either lethal or sublethal at 24-48 hours were utilized. Peripheral blood neutrophils and B-lymphocytes were studied for expression of beta-integrins (CD11b and CD11b/c) and I-A, respectively, using flow cytometry. Corresponding plasma levels of TNF alpha and interferon gamma were measured by ELISA. At 24 hr, a lethal bacterial lethal bacterial dose injection resulted in significantly higher levels of neutrophil CD11b/c expression (p < 0.005) compared with ischemia-reperfusion treatment. B-cell I-A expression was also higher in lethal sepsis. Gamma interferon levels were significantly higher in lethal sepsis compared with ischemia-reperfusion (p = 0.005). Studies over time showed that CD11b expression and interferon gamma were both more marked at 6 hr than at 24 hr in lethal sepsis. This pattern was not observed in sublethal sepsis or in ischemia-reperfusion. CD11b/c expression on the other hand remained elevated at comparable levels at 6 and 24 hr in lethal sepsis. B-cell I-A expression in ischemia-reperfusion and sublethal sepsis decreased at 24 hr compared with baseline. Lethal sepsis in rats injected with enterotoxin producing staphylococcus results in phasic alterations in neutrophil CD11b and plasma interferon levels prior to death. In analogy to the findings of monocyte decreases in DR expression observed in human trauma and sepsis, rat B-cell I-A expression showed decreases in sublethal sepsis as well as in ischemia-reperfusion injury. However, this was not observed in lethal sepsis. These findings have implications in understanding the immunologic/inflammatory changes observed in human sepsis and trauma.     

Effect of polyethylene on osteocalcin, alkaline phosphatase and procollagen secretion by human osteoblastic cells

BACKGROUND AND STUDY AIMS: Anastomotic leakage is a severe complication in gastric surgery and it is associated with a high rate of mortality. Conservative treatment sometimes is not sufficient to stem the leakages and, even when it is sufficient, it takes a long time. The present study describes the first experience in the treatment of anastomotic leakages with endoscopic clipping. PATIENTS AND METHODS: From May 1995 to December 1996, seven patients with postoperative anastomotic leakages after gastric surgery were prospectively treated in our Endoscopy Service. Metallic endoclips (MD 850, Olympus Corp., Tokyo, Japan) with prongs 12 mm long and 6 mm wide were applied, controlling the closure of the leakage by endoscopy, using radiographs to confirm the closure 24 hours later. RESULTS: Complete closure of the leakage was obtained in all seven cases. A single session of endoscopic clipping was needed for five patients while two other required, respectively, two and three sessions. The median time of leakage closure after endoscopic clipping was 2.3 days (range 1-5 days). The clips spontaneously dislodged within 1 month in five patients and within the second month in the other two patients. CONCLUSION: Endoscopic treatment of anastomotic leakages by metallic clips represents a safe and easily repeated method and, compared to conservative treatment, it seems to offer several time and cost advantages. Further studies involving a larger number of patients are needed to verify this finding.     

Intraocular concentrations of chemotherapeutic agents after systemic or local administration

OBJECTIVES: To investigate the concentrations of carboplatin and etoposide achieved in the aqueous and vitreous humors after intravenous infusion in nonhuman primates, and to investigate whether local administration of carboplatin might result in higher concentrations in the vitreous humor. METHODS: Macaca fascicularis primates were treated with 1 of 3 regimens: (1) intravenous carboplatin (18.7 mg/kg), etoposide (5 mg/kg), and vincristine sulfate (0.05 mg/kg), (2) peribulbar carboplatin (10 mg/mL), or (3) episcleral balloon carboplatin (10 mg/mL). Concentrations of chemotherapeutic agents were measured in the plasma and in the aqueous and vitreous humors. RESULTS: No measurable amount of etoposide was detected in the aqueous or vitreous humor after intravenous administration. Mean measured peak vitreous concentration of carboplatin after intravenous administration was 0.31 microg/mL, which was 1% of the peak plasma value. Mean measured peak vitreous concentrations of carboplatin after peribulbar or episcleral balloon administration were 2.38 microg/mL and 2.95 microg/mL, respectively, which represent 7.68- and 9.52-fold increases over the concentration achieved after intravenous administration. No serious toxic effect was observed in any animal. CONCLUSIONS: Peribulbar and episcleral balloon administration of carboplatin seemed to be safe and resulted in higher vitreous concentrations than intravenous administration in this model. These results suggest that these alternate routes of delivery should be explored in children with vitreous seeding of retinoblastoma.     

Amino acid levels in the hypothalamus and response to N-methyl-D-aspartate and/or dizocilpine administration during sexual maturation in female rats

Amino acid concentration in the anterior preoptic area and medial basal hypothalamus was determined by HPLC in female rats: (1) at 16 (prepubertal) vs. 30 (peripubertal) days of age and (2) after N-methyl-D-aspartate (NMDA) or dizocilpine (MK-801) administration in both groups. 30-day-old rats had higher levels of aspartate (Asp; 24%), glutamate (Glu; 49%) and glycine (Gly; 44%) and lower levels of taurine (Tau; 43%) than 16-day-old rats. In 16-day-old rats, NMDA (30 mg/kg, s.c., 10 min) increased the Glut concentration (48%). This effect was prevented by MK-801 pretreatment (1 mg/kg, s.c., 1 h), which did not modify amino acid concentrations per se. In 30-day-old rats, NMDA treatment increased Glut (24%) and asp (42%) levels. MK-801 pretreatment abolished NMDA-induced changes and reduced Tau (26%) and Gly (30%) levels. MK-801 administration alone reduced the concentration of Glut (39%), Asp (54%), Tau (33%) and Gly (31%). It is concluded that both (1) the concentration of Asp, Glu, Gly and Tau and (2) the changes induced by NMDA receptor activation or blockade are different at 16 vs. 30 days of age. The existence of a tonic (positive) control on amino acid levels linked to the NMDA receptor which would be immature or absent at 16 days of age is suggested.     

High levels of ascorbic acid, not glutathione, in the CNS of anoxia-tolerant reptiles contrasted with levels in anoxia-intolerant species

Ascorbic acid and glutathione (GSH) are antioxidants and free radical scavengers that provide the first line of defense against oxidative damage in the CNS. Using HPLC with electrochemical detection, we determined tissue contents of these antioxidants in brain and spinal cord in species with varying abilities to tolerate anoxia, including anoxia-tolerant pond and box turtles, moderately tolerant garter snakes, anoxia-intolerant clawed frogs (Xenopus laevis), and intolerant Long-Evans hooded rats. These data were compared with ascorbate and GSH levels in selected regions of guinea pig CNS, human cortex, and values from the literature. Ascorbate levels in turtles were typically 100% higher than those in rat. Cortex, olfactory bulb, and dorsal ventricular ridge had the highest content in turtle, 5-6 mumol g-1 of tissue wet weight, which was twice that in rat cortex (2.82 +/- 0.05 mumol g-1) and threefold greater than in guinea pig cortex (1.71 +/- 0.03 mumol g-1). Regionally distinct levels (2-4 mumol g-1) were found in turtle cerebellum, optic lobe, brainstem, and spinal cord, with a decreasing anterior-to-posterior gradient. Ascorbate was lowest in white matter (optic nerve) in each species. Snake cortex and brainstem had significantly higher ascorbate levels than in rat or guinea pig, although other regions had comparable or lower levels. Frog ascorbate was generally in an intermediate range between that in rat and guinea pig. In contrast to ascorbate, GSH levels in anoxia-tolerant turtles, 2-3 mumol g-1 of tissue wet weight, were similar to those in mammalian or amphibian brain, with no consistent pattern associated with anoxia tolerance. GSH levels in pond turtle CNS were significantly higher (by 10-20%) than in rat for several regions but were generally lower than in guinea pig or frog. GSH in box turtle and snake CNS were the same or lower than in rat or guinea pig. The distribution GSH in the CNS also had a decreasing anterior-to-posterior gradient but with less variability than ascorbate: levels were similar in optic nerve, brainstem, and spinal cord. The paradoxically high levels of ascorbate in turtle brain, which has a lower rate of oxidative metabolism than mammalian, suggest that ascorbate is an essential cerebral antioxidant. High levels may have evolved to protect cells from oxidative damage when aerobic metabolism resumes after a hypoxic dive.