Performance measurement of the microPET focus 120 scanner.

The microPET Focus 120 scanner is a third-generation animal PET scanner dedicated to rodent imaging. Here, we report the results of scanner performance testing. METHODS: A (68)Ge point source was used to measure energy resolution, which was determined for each crystal and averaged. Spatial resolution was measured using a (22)Na point source with a nominal size of 0.25 mm at the system center and various off-center positions. Absolute sensitivity without attenuation was determined by extrapolating the data measured using an (18)F line source and multiple layers of absorbers. Scatter fraction and counting rate performance were measured using 2 different cylindric phantoms simulating rat and mouse bodies. Sensitivity, scatter fraction, and noise equivalent counting rate (NECR) experiments were repeated under 4 different conditions (energy window, 250 approximately 750 keV or 350 approximately 650 keV; coincidence window, 6 or 10 ns). A performance phantom with hot-rod inserts of various sizes was scanned, and several animal studies were also performed. RESULTS: Energy resolution at a 511-keV photopeak was 18.3% on average. Radial, tangential, and axial resolution of images reconstructed with the Fourier rebinning (FORE) and filtered backprojection (FBP) algorithms were 1.18 (radial), 1.13 (tangential), and 1.45 mm full width at half maximum (FWHM) (axial) at center and 2.35 (radial), 1.66 (tangential), and 2.00 mm FWHM (axial) at a radial offset of 2 cm. Absolute sensitivities at transaxial and axial centers were 7.0% (250 approximately 750 keV, 10 ns), 6.7% (250 approximately 750 keV, 6 ns), 4.0% (350 approximately 650 keV, 10 ns), and 3.8% (350 approximately 650 keV, 6 ns). Scatter fractions were 15.9% (mouse phantom) and 35.0% (rat phantom) for 250 approximately 750 keV and 6 ns. Peak NECR was 869 kcps at 3,242 kBq/mL (mouse phantom) and 228 kcps at 290 kBq/mL (rat phantom) at 250 approximately 750 keV and 6 ns. Hot-rod inserts of 1.6-mm diameter were clearly identified, and animal studies illustrated the feasibility of this system for studies of whole rodents and mid-sized animal brains. CONCLUSION: The results of this independent field test showed the improved physical characteristics of the F120 scanner over the previous microPET series systems. This system will be useful for imaging studies on small rodents and brains of larger animals.     

Clinical Significance of an Early Protocol Biopsy in Living-Donor Renal Transplantation: Ten-Year Experience at a Single Center

We report here our 10-year experience of a biopsy performed at day 14 after transplantation in 304 patients with stable graft function. The factors that may have influenced subclinical rejection were analyzed according to histology. The incidence of subclinical rejection was 13.2%. Addition of mycophenolate mofetile (MMF) as a primary immunosuppressant significantly decreased the incidence of subclinical rejection compared with patients without such treatment (odds ratio, 0.23; p < 0.05). On the other hand, HLA-DR antigen mismatch (odds ratio, 2.39) and unrelated donor (odds ratio, 2.10) were also significantly associated with decreased subclinical rejection (p < 0.05). The incidence of acute rejection in patients with normal findings was lower than in those with borderline changes or subclinical rejection (0.23 +/- 0.05 vs. 0.48 +/- 0.07 and 0.60 +/- 0.11, respectively; p < 0.05). The graft survival rates in patients with subclinical rejection were lower than in patients with normal or borderline changes at 1 (88.4% vs. 97.9% and 99.1%; p < 0.05), 5 (77.8% vs. 96.2% and 95.9%; p < 0.05) and 10 (62.3% vs. 96.2% and 93.7%; p < 0.05) years. Thus, a protocol biopsy performed on day 14 after transplantation is useful for predicting graft survival. Triple therapy including MMF, related donor and HLA-DR antigen match are important factors for reducing subclinical rejection in living-donor renal transplantation.     

Rapidly Progressive Toxic Leukoencephalomyelopathy with Myelodysplastic Syndrome: a Clinicopathological Correlation

Neurological disorders induced by long-term exposure to organic solvents typically have a slowly progressive clinical course, which may be arrested or even reversed following discontinuation of exposure. We report an unusual case of rapidly progressive toxic leukoencephalomyelopathy in a 29-year-old man who had worked at a chemical factory that used toluene for the manufacture of nylon 66 for 5 years. He presented with progressive weakness of legs, recurrent seizures, and cognitive decline. Widespread white-matter changes in the brain and spinal cord, and myelodysplastic syndrome were noted. He died 6 months after the onset of his symptoms, and autopsy showed discrete multifocal demyelination and necrosis in the central nervous system, and dysplastic cells of erythroid, myeloid, and megakaryotic lineages in blood vessels. The co-occurrence of leukoencephalomyelopathy and myelodysplastic syndrome highlights the vulnerability of the white matter and bone marrow to injury from organic solvents. Intravascular congestion of dysplastic hematopoietic cells might have led to his unusually rapid progression of leukoencephalomyelopathy.     

Antiviral triterpenes fromPrunella vulgaris

Two triterpenes 1 and 2 with antiviral activity againstHerpes simplex virus type 1in vitro were isolated fromPrunella vulgaris. Each compound caused a significant reduction in viral cytopathic effect whenvero cells were exposed to them for 72 hours after viral challenge. They were identified asbetulinic acid(1) and 2α, 3α-dihydroxyurs-12-en-28-oic acid(2) on the basis of their spectroscopic properties. The antiviral activity of them was estimated as EC₅₀=30 μg/ml(1) and 8 μg/ml(2), respectively by plaque reduction assay.     

Extensive Aberrant Mongolian Spot

A 9-month-old male infant had generalized diffuse blue-gray pigmentation over most of his body, sparing the scalp, face, neck, palms, soles, periumbilical area, genital area, and nipples. Within the lesion, there were several conspicuous macules of considerably darker hue. Histologic examination revealed numerous dermal melanocytes. By 16 months of age, the child's blue-gray pigmentation had decreased substantially.     

Detailed gene copy number and RNA expression analysis of the 17q12-23 region in primary breast cancers

Chromosome region 17q12-23 commonly shows an increase in DNA copy number in breast cancers, suggesting that several oncogenes are located at this site. We performed a high-resolution expression array and comparative genomic hybridization analysis of genes mapped to the entire 17q12-23 region, to identify novel candidate oncogenes. We identified 24 genes that showed significant overexpression in breast cancers with gain of 17q12-23, compared to cancers without gain. These genes included previously identified oncogenes, together with several novel candidate oncogenes. FISH analysis using specific gene probes hybridized to tissue arrays confirmed the underlying amplification of overexpressed genes. This high-resolution analysis of the 17q12-23 region indicates that several established and novel candidate oncogenes, including a Wnt-signaling pathway member, are amplified and overexpressed within individual primary breast cancer samples. We were also able to confirm the presence of two apparently separate and reciprocally amplified groups of genes within this region. Investigation of these genes and their functional interactions will facilitate our understanding of breast oncogenesis and optimal management of this disease.     

Preoperative chemoradiation and pancreaticoduodenectomy with portal vein resection for localized advanced pancreatic cancer

Pancreatic adenocarcinoma is a common disease that is rarely cured. Surgical resection remains the only treatment modality that has a curative potential, although the majority of patients are unsuitable for resection at the time of diagnosis. Chemoradiation therapy prior to a pancreaticoduodenectomy ensures that a patient who undergoes a complete resection multimodality therapy, avoids a resection in patients who have a rapidly progressive disease, and allows radiation therapy to be given to well oxygenated cells before, surgical devasculation. This permits the chance of resection of an unresectable pancreatic cancer by downstaging. A patient with cytologic proof of localized adenocarcinoma of the pancreatic head received an intravenously chemoradiation (Taxol, 50 mg/m2 intravenously for 3 hours week on 5 cycles, of Gemcytabine 1000 mg/m2/day intravenously for 3 days week on 2 cycles, of 4500 cGy) with the intention of proceeding to a resection operation, restaging was performed by computed tomography, magnetic resonance imaging from 5 weeks every months due to ongoing decreasing of tumor size after the chemoradiation. At laparotomy, the patient didn't have suspected metastatic disease, the tumor size was 2 X 3 cm on the pancreas head and was infiltrating into the portal vein for about 3 cm length on right side. A pancreaticoduodenectomy along with a portal vein and superior mesenteric vein resection was done and then reconstruction of a vascular anastomosis by using the right side of the internal jugular vein. Perioperative complications didn't occur. In conclusion, preoperative chemoradiation of a localized advanced pancreatic tumor has no added risk to the operative complications and the prospects for resectability are enhanced.