Reproducibility of 18F-FDG microPET studies in mouse tumor xenografts.

(18)F-FDG has been used to image mouse xenograft models with small-animal PET for therapy response. However, the reproducibility of serial scans has not been determined. The purpose of this study was to determine the reproducibility of (18)F-FDG small-animal PET studies. METHODS: Mouse tumor xenografts were formed with B16F10 murine melanoma cells. A 7-min small-animal PET scan was performed 1 h after a 3.7- to 7.4-MBq (18)F-FDG injection via the tail vein. A second small-animal PET scan was performed 6 h later after reinjection of (18)F-FDG. Twenty-five sets of studies were performed. Mean injected dose per gram (%ID/g) values were calculated from tumor regions of interest. The coefficient of variation (COV) from studies performed on the same day was calculated to determine the reproducibility. Activity from the second scans performed after 6 h were adjusted by subtracting the estimated residual activity from the first (18)F-FDG injection. For 7 datasets, an additional scan immediately before the second injection was performed, and residual activity from this additional delayed scan was subtracted from the activity of the second injection. COVs of both subtraction methods were compared. Blood glucose values were measured at the time of injection and used to correct the %ID/g values. RESULTS: The COV for the mean %ID/g between (18)F-FDG small-animal PET scans performed on the same day 6 h apart was 15.4% +/- 12.6%. The delayed scan subtraction method did not produce any significant change in the COV. Blood glucose correction increased the COV. The injected dose, tumor size, and body weight did not appear to contribute to the variability of the scans. CONCLUSION: (18)F-FDG small-animal PET mouse xenograft studies were reproducible with moderately low variability. Therefore, serial small-animal PET studies may be performed with reasonable accuracy to measure tumor response to therapy.     

Maturation of immature oocytes by coculture with granulosa cells

To increase the number of embryos available for transfer, immature human oocytes were cocultured with granulosa cells from preovulatory follicles. Greater numbers of immature oocytes incubated with granulosa cells had dispersion of the cumulus and corona cells compared with immature oocytes cultured in media alone. Fifty-four percent of immature oocytes were fertilized after coculture with granulosa cells compared with 20% fertilization of immature oocytes cultured without granulosa cells. There were no cases in which only embryos developed from immature oocytes were transferred, and thus we could not determine if the immature oocytes could contribute to a pregnancy.     

Metastatic mammary carcinoma of the middle ear

Malignancies of the middle ear and mastoid are rare and secondaries in the ear are extremely rare. A rare case of metastic adenocarcinoma from the breast is presented herewith.     

Localization of simian immunodeficiency virus in the central nervous system of rhesus monkeys.

Simian immunodeficiency virus (SIV), like the human immunodeficiency virus (HIV), is a lentivirus that is both immunosuppressive and neurovirulent. Rhesus macaques (Macaca mulatta) inoculated with SIV often develop a giant cell encephalitis similar to that seen in humans infected with HIV. The authors examined SIV expression by immunohistochemistry and RNA in situ hybridization in the cerebrum, cerebellum, choroid plexus, and spinal cord from five macaques with and two macaques without giant cell encephalitis. Selected portions of the central nervous system (CNS) also were examined by electron microscopy. Simian immunodeficiency virus was detected in the CNS of all seven monkeys whether or not they had giant cell encephalitis. Both SIV antigen and RNA were present in all levels of the CNS examined. Macrophage/giant cell lesions always contained viral RNA and antigen and were the only sites where viral particles were detected by electron microscopy. However, SIV antigen and RNA also were commonly associated with small vessels, the choroid plexus, and meninges; these were the only locations where virus was detected in animals without giant cell encephalitis. Immunophenotyping showed that the cellular infiltrates consisted primarily of monocyte/macrophages and occasional CD8-positive T cells. Macrophages and T cells also were present in the stroma of the choroid plexus and were intimately associated with vessels in the CNS of SIV-infected but not uninfected macaques. Simian immunodeficiency virus infection of the macaque CNS provides an excellent model for studying the pathogenesis, treatment, and prevention of HIV-1-encephalitis.     

Role of imprint cytology in the diagnosis of gastrointestinal tract malignancies

Endoscopic biopsies obtained from 275 patients (180 from the upper gastrointestinal tract and 95 from the lower gastrointestinal tract) were studied to compare the accuracy of biopsy imprint cytology and histology in the diagnosis of gastrointestinal lesions, and also to establish the degree of reliability of imprint cytology alone for an early diagnosis of malignancy. Biopsy histology results were found to be correct in 100% cases. Imprint cytology had an overall accuracy of 100%, 96.7%, 95.8% and 95.8% for the diagnosis of malignancies of the oesophagus, stomach, duodenum and colorectum respectively. False negative results were obtained with lymphomas. Regenerative cellular atypia was an important cause for false positive results. It was concluded that imprint cytology can serve as a useful and simple tool for an immediate diagnosis of malignancy. This should be subsequently correlated with histopathology which facilitates exact tumour typing and assessment of tumour invasion.     

Bystander CD8 T-cell-mediated demyelination is interferon-gamma-dependent in a coronavirus model of multiple sclerosis

Mice infected with the coronavirus mouse hepatitis virus, strain JHM (JHM) develop a disease that shares many histological characteristics with multiple sclerosis. We previously demonstrated that JHM-infected mice that only have CD8 T cells specific for an epitope not in the virus develop demyelination on specific activation of these cells. Herein we show that this process of bystander T-cell-mediated demyelination is interferon-gamma (IFN-gamma)-dependent. The absence of IFN-gamma abrogated demyelination but did not change T-cell infiltration or expression levels of inflammatory cytokines or chemokines in the spinal cord. These results are consistent with models in which IFN-gamma contributes to CD8 T-cell-mediated demyelination by activation of macrophages/microglia, the final effector cells in the disease process.     

When genetic distance matters: measuring genetic differentiation at microsatellite loci in whole-genome scans of recent and incipient mosquito species

Genetic distance measurements are an important tool to differentiate field populations of disease vectors such as the mosquito vectors of malaria. Here, we have measured the genetic differentiation between Anopheles arabiensis and Anopheles gambiae, as well as between proposed emerging species of the latter taxon, in whole genome scans by using 23-25 microsatellite loci. In doing so, we have reviewed and evaluated the advantages and disadvantages of standard parameters of genetic distance, F(ST), R(ST), (delta mu)(2), and D. Further, we have introduced new parameters, D' and D(K), which have well defined statistical significance tests and complement the standard parameters to advantage. D' is a modification of D, whereas D(K) is a measure of covariance based on Pearson's correlation coefficient. We find that A. gambiae and A. arabiensis are closely related at most autosomal loci but appear to be distantly related on the basis of X-linked chromosomal loci within the chromosomal Xag inversion. The M and S molecular forms of A. gambiae are practically indistinguishable but differ significantly at two microsatellite loci from the proximal region of the X, outside the Xag inversion. At one of these loci, both M and S molecular forms differ significantly from A. arabiensis, but remarkably, at the other locus, A. arabiensis is indistinguishable from the M molecular form of A. gambiae. These data support the recent proposal of genetically differentiated M and S molecular forms of A. gambiae.