Potential doubling time and tumour doubling time in meningiomas and neurinomas

Summary Cell kinetic study plays an important role in treatment planning of brain tumour patients. MIB-1 antibody has recently become available, which detects Ki-67 antigen even in the formalin-fixed paraffin-embedded specimens. We performed MIB-1 immunostaining in 50 meningiomas and 50 neurinomas, and estimated the cell cycle time (tc) and potential doubling time (Tpot) from MIB-1 staining index (MIB-1 SI) and mitotic index (MI). MIB-1 SI logarithmically correlated with MI in both meningiomas and neurinomas. The tc and the Tpot were expressed as a function of the mitosis time (tm), while the tm is known to be around one hour and not exceeding two hours. When the tm was assumed to be one hour, the average tcs of meningiomas and neurinomas were 6.53±3.56 days and 7.67±3.27 days, respectively. The Tpots were447 × (MIB-1 SI)^–1.29 × tm in meningiomas, and490 × (MIB-1 SI) ^–0.98 × tm in neurinomas.The tumour doubling times (Tds) were calculated from serial imaging studies in 22 neurinomas and 15 meningiomas. The Tds were formulated as794 × (MIB-1 SI) ^–0.83 in meningiomas and1380 × (MIB-1 SI) ^–0.97 in neurinomas. Most of the Tds correlated well with the Tpots in meningiomas and neurinomas, and exceeded values of the Tpot when the tm is assumed to be one hour, although a few tumours showed unexpectedly longer Tds. The Tpot and the tc estimated from MIB-1 SI and MI are clinically useful parameters for predicting the growth potential of meningiomas and neurinomas where no other simple methods are available.     

Angiographically occult vascular malformations in the posterior fossa

Three cases of spontaneous intraparenchymal hemorrhage in the posterior fossa were operated upon, and the diagnosis of thrombosed vascular malformation was histologically confirmed in two of them. So-called "angiographically occult" vascular malformations often present characteristic magnetic resonance (MR) images, namely, iso- to high intensity signal core surrounded by a low intensity signal rim or area on both T1 and T2 weighted images. Such findings are thought to indicate that subacute and chronic intraparenchymal hematoma has a relatively short T1 and long T2 relaxation times, resulting in an area of relatively increased signal intensity, and that hemosiderin deposits apparently decrease T2 relaxation time by paramagnetic effect. Most such lesions do not show significant perifocal edema. Occasionally, however, perifocal edema may be seen as in our Case 3, and the differential diagnosis from the tumor, particularly bleeding tumor, may become difficult even with the recent technical standards of high resolution CT and MRI. Reasons responsible for non-visualization of such vascular malformations at angiography are discussed. Small size of the lesion, slow blood flow through it, compression by adjacent clot or gliotic scar, spontaneous or secondary thrombosis with hyalin degeneration, and destruction at its rupture are possible factors.     

Seminoma in a postmenopausal woman with a Y;15 translocation in peripheral blood lymphocytes and a t(Y;15)/45,X Turner mosaic pattern in skin fibroblasts.

We report an unusual case of a 55 year old Japanese woman with a seminoma but relatively normal menses. The patient was a phenotypic female with late onset menarche (18 years of age), who was amenorrhoeic for the first year, followed by menses of one to three days' slight flow with dysmenorrhoea, but an otherwise normal menstrual history. A typical seminoma was removed from the left adnexal region and an immature testis was identified separately as an associated right adnexal mass. Repeated karyotypic studies on peripheral blood lymphocyte cultures showed only 46,X,-Y,t(Y;15)(q12;p13). Cytogenetic examination of the patient's younger brother, who had fathered three healthy children, showed an identical karyotype. Mosaicism of 46,X,-Y,t(Y;15)(q12;p13)/45,X cell lines was found in skin samples from the patient's elbow and genital regions, although there were no clinical stigmata of Turner syndrome. An androgen receptor binding assay of cultured genital skin fibroblasts was negative. Molecular analysis using Southern blot hybridisation, PCR, and direct DNA sequencing showed that neither the patient nor her brother had a detectable deletion or other abnormalities of Y chromosome sequences, including the SRY (sex determining region of the Y chromosome) gene sequence. These findings suggest that Turner mosaicism of the 45,X cell line may have contributed to this atypical presentation in an XY female, although we cannot exclude abnormalities of other genes related to sex differentiation.     

Morphogenesis of the secondary palate in mouse embryos with special reference to the development of rugae

Morphological studies of secondary palate formation, with special reference to the development of rugae, were carried out on Jcl:ICR mouse embryos. Three rugae were observed on the anterior part of the future oral surface of the vertically developing palatal shelves in 13-day embryos. Rugae increased in number as the development of the palatal shelves proceeded, and five to six prominent rugae were observed in 14-day embryos just prior to shelf elevation. The folding of these five to six rugae progressed in conjunction with the formation of a sharp, valley-like groove at the base of the anterior two-fifths of the vertical palatal shelves. As palatal shelves elevated, the groove disappeared gradually, and, accordingly, the folding of rugae loosened. In the groove region, the superficial epithelial cells were roundish, while the basal ones were elongated. Such characteristic features were no longer observed when the disappearance of the groove was completed. Eight rugae were observed on the future hard palate of 14-day embryos with already completed palatal fusion. An additional ruga was frequently found in 15-day embryos, and the pattern then was almost the same as that of an adult. Epithelial thickening and condensation at the rugae region, as well as mesenchymal condensation under the epithelium of the rugae, were confirmed in embryos both before and after elevation of the palatal shelves. There is a possibility that these structural characteristics observed in the epithelial and mesenchymal cells of the rugae and groove regions may be related to palatal shelf elevation.     

Suitable image parameters and analytical method for quantitatively measuring cerebral blood flow volume with phase-contrast magnetic resonance imaging

The aim of this study was to determine suitable image parameters and an analytical method for phase-contrast magnetic resonance imaging (PC-MRI) as a means of measuring cerebral blood flow volume. This was done by constructing an experimental model and applying the results to a clinical application. The experimental model was constructed from the aorta of a bull and circulating isotonic saline. The image parameters of PC-MRI (repetition time, flip angle, matrix, velocity rate encoding, and the use of square pixels) were studied with percent flow volume (the ratio of actual flow volume to measured flow volume). The most suitable image parameters for accurate blood flow measurement were as follows: repetition time, 50 msec; flip angle, 20 degrees; and a 512 x 256 matrix without square pixels. Furthermore, velocity rate encoding should be set ranging from the maximum flow velocity in the vessel to five times this value. The correction in measuring blood flow was done with the intensity of the region of interest established in the background. With these parameters for PC-MRI, percent flow volume was greater than 90%. Using the image parameters for PC-MRI and the analytical method described above, we evaluated cerebral blood flow volume in 12 patients with occlusive disease of the major cervical arteries. The results were compared with conventional xenon computed tomography. The values found with both methods showed good correlation. Thus, we concluded that PC-MRI was a noninvasive method for evaluating cerebral blood flow in patients with occlusive disease of the major cervical arteries.