Biomedical subjects
Publications and source records attributed to S Nakasu.
A spontaneous regression of the lesion seen in sequential computertomographic scans does not necessarily indicate a non-neoplastic nature of the pathological process. Two patients with pathologically verified glioma of the brain which showed a temporary regression of the mass effect are reported, and the mechanism of the regression of computertomographic mass signs is discussed.
The product of gene 8 (gp8) of T3 phage was purified from proheads, heads, and extract prepared from cells infected with a mutant defective in gene 10 (major head protein) (10- extract). gp8, when purified by hydrophobic column chromatography from proheads solubilized by guanidine hydrochloride, did not show any ordered structure. gp8 from heads ruptured by sucrose shock sedimented with a sedimentation coefficient of 20 S (20 S assembly). Electron micrography of 20 S assemblies showed ring structures displaying radial symmetry. When the gp8 in 20 S assemblies was concentrated, it formed two-dimensional crystals. gp8 in 20 S material was detected in 10- extract by sedimentation analysis. gp8 purified from 10- extract by anti-gp8 antibody column chromatography had an ordered structure identical to that of the 20 S assembly from heads. The effect of anti-gp8 serum on the activity of proheads and heads was examined by in vitro complementation. Anti-gp8 serum preabsorbed with 5- X 8- -extracted inactivated proheads and heads. Anti-gp8 serum preabsorbed with proheads inactivated heads but not proheads. Similarly, anti-gp8 serum preabsorbed with phage-inactivated proheads but not heads. From these results, it is concluded that gp8 in proheads and heads is accessible to antibodies and that different antigenic sites of gp8 are exposed in proheads and heads.
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We report an unusual case of meningeal dissemination of medulloblastoma in which multiple cerebrospinal fluid entrapment cysts developed within the cerebral fissures and cisterns. The condition was first diagnosed by CT. Cysts reduced in size following radiotherapy.
The product of gene 8 (gp8) of T3 phage is one of the minor head proteins located at the phage head-tail junction. To determine the role of gp8, an amber (8-) and four temperature-sensitive mutants (ts8) were characterized by sedimentation analysis, polyacrylamide gel electrophoresis, and extract complementation. Neither DNA-containing particles nor empty particles were formed in cells infected with 8-. In addition, prohead assembly was greatly reduced. Prohead assembly was also blocked in cells infected with all ts8 mutants at 42 degrees and with some ts8 even at 37 degrees. Proheads containing gpts8 were converted to empty heads when cell lysates were treated with chloroform. The protein compositions of proheads showed that the minor head proteins, gp8, gp15, and gp16, were lost from proheads formed in cells infected with ts8, but these minor proteins were present in proheads formed in cells infected with double mutants of ts8 and 5- or 19-, which are defective in DNA synthesis or DNA maturation, respectively. In vitro complementation experiments suggested that a ts mutation in gene 8 affected not only DNA packaging but also subsequent assembly steps. From these results, it is concluded that gp8 plays multiple roles in T3 phage morphogenesis, including prohead assembly, prohead stabilization, DNA packaging, and subsequent events.
Dynamic computed tomography was performed on patients with cerebral vascular anomalies, the density-versus-time curves were derived, and the gray-scale functional images demonstrating the pixel-by-pixel distribution of several flow parameters were processed. This noninvasive method was found to be useful not only in delineating the vascular anomalies with their afferent and efferent vessels, but also in detecting the abnormal flow patterns within and outside the vascular anomalies. Limitations and distinct advantages of this technique are briefly discussed.
The familial occurrence of intracranial tumors is rare except in patients with phacomatoses. The occurrence of suprasellar yolk-sac tumors in two sisters without phacomatoses is reported. The pertinent literature is reviewed, and the possible role of heredity in the pathogenesis of these tumors is discussed briefly.
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Intracranial intradural epidermoid tumours have been known to show characteristic CT features consisting of non-enhancing lucent lesions with sharply defined margins that are often irregular and scalloped. Since the epidermoid tumours are benign, potentially curable lesions, it should be also noted that they may occasionally show atypical CT features such as dense lesion, definite marginal enhancement following contrast medium injection, or tumour associated with large, heavy calcifications. Four such atypical cases are reported, and the literature is reviewed.
Calvarial bone defect associated with a hugh neurofibroma in the region of the lambdoid suture was reported in a 42-year-old man with v. Recklinghausen's neurofibromatosis. An enlarging occipital tumor was first noted at age 4 similar to or approximately 5, and an operation was performed at age 12. Lambda defect was noted at that time, but the operative diagnosis was, apparently, "meningocele". Available literature was reviewed, and the significance of calvarial bone defect in the region of the lambdoid suture as a manifestation of v. Recklinghausen's disease was stressed. Lambda defect witn no sclerosing margin, particularly if associated with hypoplasia of the ipsilateral mastoid cells, has been known to represent the primary nature of the bone defect due to mesodermal dysplasia. In the present case, plain radiographs of the skull revealed abnormal sclerotic change around the bone defect. It is suggested that such an osteoblastic change may well indicate the secondary nature of the bone defect due to the presence of overlying neurogenic tumor.
Congenital absence of one internal carotid artery was found by angiography in a woman of 52 years who had subarachnoid hemorrhage. The absence of the bony carotid canal on the affected side substantiated the congenital nature of this rare vascular anomaly. We believe this to be the first report of absence of the bony carotid canal and the intracavernous portion of the internal carotid artery confirmed by computed tomography and cavernous sinography.
Two cases of craniopharyngioma presenting with amenorrhea-galactorrhea syndrome due to hyperprolactinemia are reported. After operation and irradiation, the tumor reduced markedly in size. Coincidental decrease in plasma prolactin level and restoration of menstruation seem to support the view that the hypothalamic prolactin inhibiting factor (PIF) had played an important role in hyperprolactinemia in these two patients.
Ischemic neuropathy is a previously described but rarely encountered complication of therapeutic embolization. Two cases of peripheral facial nerve palsy following embolization of branches of the external carotid artery are reported, and the possible mechanism is discussed.