CT findings of medulloblastoma

Computed tomography (CT) of 11 patients with medulloblastoma was evaluated. 6 of them showed solid, nearly homogenous lesions and definite enhancement after infusion of contrast medium. However, 5 cases showed heterogenous mass lesions composed of the areas of low density and iso- or slightly high density which was attenuated by contrast enhancement. Histological examinations revealed that 2 cases had differentiated medulloblastomas, but the other 3 typical medulloblastomas. It should be reminded in the differential diagnosis of cerebellar tumors of pediatric patients that medulloblastoma can reveal heterogenous mass in CT scan.

[Histopathological study of aging of the posterior portion of human cervical vertebral bodies and discs--with special reference to the early ossification of the posterior longitudinal ligament]

Ossification of the posterior longitudinal ligament ( OPLL ) of the cervical spine is a disease causing spinal canal stenosis and, henceforth , spinal cord compression. This ossification is found approximately in three percent of the adult Japanese, but it is also found to be present among Chinese, Korean and other South-East Asians, whereas the incidence among Caucasians was reported to be significantly low. The etiology of this interesting ossification is still unknown although multidisciplinary studies have been carried out in Japan in recent years. The purpose of the present study is to find an early ossification of the posterior longitudinal ligament of the cervical spine and to see its relationship with other chronological changes of the surrounding structures.

MATERIAL AND METHOD

One hundred and forty-one cervical spinal columns were obtained en bloc from C2 to C7 from the autopsied bodies at Juntendo University Hospital and at the Tokyo Metropolitan Medical Examiners' Office. There were 89 males and 52 females with a wide age distribution. A 66 year-old male case with advanced continuous OPLL died at Juntendo University Hospital was added to the study. The specimens were either cross-sectioned or sagittally sectioned, and studied soft-ray-roentgenologically and histopathologically.

RESULTS

There were specimens after the third decade of life showing micro-ossification along the midline of the posterior aspect of the vertebral body on cross-section as well as micro-ossification or hyperostosis adjacent to the posterior corner of the vertebral body on sagittal section. These micro-ossification or hyperostosis seemed to be a product of a physiological aging process, but could be considered as a precursor of the OPLL . The periosteum was well demonstrated on the posterior aspect of the vertebral body in the first two decades of life, but it became inconspicuous with age. In the adult spine there was no clear delineation between the deep layer of the posterior longitudinal ligament and the fibrous layer of the periosteum . The cambium layer looked absent on hematoxylin-eosin stain. However, on Giemsa stain there appeared a thin layer which would present increased cellular activity between the body and what appeared to be the fibrous layer of the periosteal. This layer was considered to be a 'sleeping cambium layer' for which it was named 'latent periostium layer (LPL)'.(ABSTRACT TRUNCATED AT 400 WORDS)

Genetic regulation of erythrocyte autoantibody production in New Zealand black mice

The incidences of positive anti-erythrocyte autoantibodies (AEA) in New Zealand Black (NZB), C57BL/6, their F1, F2 hybrid, and the F1 X NZB backcross mice were 100, 0, 0, 17, and 51%, respectively. This finding is in keeping with the idea that a combined effect of one to three dominant predisposing NZB gene(s) and a single dominant modifying C57BL/6 gene regulates the AEA production. Studies suggested that the modifying locus Aem-1 is loosely linked to Mup-1 locus on chromosome 4, and the gene order is Aem-1: Mup-1: Gpd-1. We analyzed the effects of the Aem-1 locus on other autoimmune traits and found that the gene action of Aem-1 is unrelated to the spontaneous productions of dsDNA-specific antibodies, the retroviral gp70-anti-gp70 immune complexes and natural thymocytotoxic autoantibodies and to the serum level of retroviral gp70. A significant association was observed between the negative AEA and the low (normal) serum IgM level in (C57BL/6 X NZB)F1 X NZB backcross mice. It remains to be determined whether the Aem-1 locus also controls the serum IgM level.

Rightward superiority of eye movements in a bimanual aiming task

To examine the role of visual monitoring in the between-hand differences in skilled manual movements, eye movements and performance during bimanual aiming tasks were analysed. When subjects were required to make bimanual aiming responses to symmetrically placed targets, they preferentially monitored the movements of the right hand, resulting in better performance on the right hand. In addition, manipulation of the subject's gaze showed that the movements of the right hand were more influenced by visual monitoring than those of the left hand. The results were interpreted as showing that the between-hand differences in skilled movements are mainly due to the different efficiency in the use of visual monitoring.

Cell movements in a living mammalian tissue: long-term observation of individual cells in wounded corneal endothelia of cats

Although the cells in tissues are known to be motile under special conditions (e.g., during tissue turnover or wound healing), there are not many reports that polygonal cells covering an area without leaving any gaps are also capable of movement. In the present study, cell movements (cell shifting and rearrangement) in a living mammalian eye tissue were documented by identifying and locating individual cells over intervals as long as 100 days. Cat corneal endothelium, a monolayered cell sheet, was wounded by removing a small number (about 180) of endothelial cells from the internal lining of the cornea. Healing of the wounded tissue was observed with a wide-view specular microscope applied to the outer surface of the cornea, enabling us to identify individual cells for as long as two to three months. Cells surrounding the wound underwent areal enlargement, elongated toward the wound, and shifted to cover the wound surface. During days 4-7, cells became rearranged by changing neighbors in such a way that they retained their enlarged size but recovered their non-elongated, original shape. This pattern of cell rearrangement was interpreted by a computer simulation which assumed that cells shorten their boundary length while maintaining contacts with contiguous cells. After day 7, the enlarged cells adjacent to the wounded area gradually contracted and pulled surrounding cells toward the wounded area. These movements were followed by a temporary halt in cell shifting, then by a recovery of shifting and cell elongation. These movements are interpreted as a result of the contractility of endothelial cell microfilaments.

[Insulin action on adenylate cyclase. The effect of insulin on adenylate cyclase of rat fat cells in the presence of theophylline]

Insulin-effects on adenylate cyclase activity, cyclic AMP (cAMP) content and free fatty acid (FFA) accumulation of rat epididymal fat cells were examined under conditions of maximal inhibition of phosphodiesterase by sufficient amounts of theophylline for the purpose of localizing the site of the antilipolytic action of insulin. After brief preincubation of the cells with physiological amounts of insulin in the presence or absence of 0.1 mM adrenalineee, fat cells were homogenized following the addition of theophylline and then further incubated. Under these conditions, small but significant enhancement of adenylate cyclase activity, cAMP content and FFA accumulation by insulin alone was observed, while insulin remarkably inhibited adrenalin-stimulated FFA accumulation, reducing adenylate cyclase activity and cAMP levels. This increase of cAMP content by insulin was only seen 5 or 15 minutes after the addition of theophylline. Furthermore, this insulin effect was also observed in the experiments which were performed in a medium containing high concentrations of albumin (2%). The concomitant accumulation of FFA might have resulted from the stimulation of lipolysis, rather than from the synthesis of FFA, since there was no added glucose in the medium. And finally, the hydrolysis of 14C-tripalmitate by a fraction of the cell homogenate under the presence of theophylline was more extensive after preincubation of the cells with insulin than without insulin. In summary, insulin, which is recognized as a typical antilipolytic hormone, activated adenylate cyclase and increased lipolysis at its physiological concentrations when it alone exerted its effect upon fat cells under the conditions where phosphodiesterase was completely inhibited by theophylline. Accordingly, the present results indicate the bimodal effect of insulin on adenylate cyclase and lipolysis under the presence of theophylline; enhancement when applied alone, and depression with adrenalin. So it is most likely that the "negative synergism" occurs as a net effect when a mild activator acts together competitively with a strong activator toward the same target. These data suggest the fundamental roles of adenylate cyclase systems in the mechanism of lipolysis regulation by insulin.

[Comparative study on cefmetazole and cefazolin in the treatment of suppurative otitis media]

Cefmetazole (CMZ) was compared to cefazolin (CEZ) for efficacy and safety in the treatment of suppurative otitis media (including acute otitis media and chronic otitis media in acute aggravating stage) under well controlled clinical trials. The therapeutic effects were analyzed statistically in 172 patients (82 administered CMZ, 90 administered CEZ). The adverse reactions were also analyzed statistically in 199 patients (CMZ 99, CEZ 100) in whom the judgement was possible. 1. The efficacy rate of CMZ (72.3% for good to excellent response) was assessed by physicians in charge to be similar to that of CEZ (59.3%). This was the same being assessed by the committee, too (CMZ 64.6%, CEZ 56.7%). 2. When patients were classified into 2 groups (acute otitis media, chronic otitis media in acute aggravating stage) with respect to diagnosis, statistically significant difference in clinical efficacy assessed by physicians in charge was observed in the cases with chronic otitis media (CMZ, CEZ). In addition, the improvements of flares on the drum membrane and the mucous membrane of eardrum were significantly better in the CMZ group than in the CEZ group. 3. Bacteriologically, 16 cases (19.8%) of S. aureus were resistant to CEZ, while only 1 case (1.2%) to CMZ. CMZ was judged to be effective in 5 of the 6 cases in which CEZ-resistant strains were detected. 4. Side effects were found in 2 cases (2.0%) treated with CMZ: one complained of retching and abdominal pain and the other developed skin eruption. On the other hand, only 1 case (1.0%) developed skin eruption in the CEZ group. These results suggest that CMZ is a new antibiotic agent which is highly valuable in the treatment of suppurative otitis media.

[Effects of dihydroergotamine mesylate (DEM) on the cardiovascular and nervous systems (author's transl)]

Effects of DEM on the cardiovascular, autonomic, and central nervous systems were studied using dogs, rats and rabbits. DEM showed relatively weak effects on the EEG in curarized rabbits and on ambulatory and drinking activities in rats. DEM suppressed dose-dependently the pressor responses induced by norepinephrine, serotonin and bilateral carotid occlusion, but had no effect on the depressor responses induced by acetylcholine and electrical stimulation to the postganglionic vagus nerve in anesthetized dogs. DEM produced a dose-dependent increase in blood pressure, a dose-dependent decrease in heart rate, a transient decrease in respiration rate, and little change in the ECG of anesthetized dogs. The pressor responses induced by DEM were inhibited by phentolamine, methysergide, and indomethacin in anesthetized dogs. With canine femoral arteries, DEM-induced contractions were blocked 10% by phentolamine, 60% by methysergide, and enhanced 10% by indomethacin. On the other hand, DEM-induced contractions of the femoral veins were blocked 30% by phentolamine, 60% by indomethacin, and 10% by methysergide. DEM provoked a significant increase in the level of prostaglandin E in the bathing fluid of the veins but not in that of the arteries. The results suggest that the arterioconstrictor responses induced by DEM are mediated mainly through the serotonin receptors, and the venoconstrictor responses induced by DEM mainly through the enhanced synthesis of prostaglandin E.

[Comparative responsiveness of isolated saphenous, femoral and external carotid arteries and veins of dogs to dihydroergotamine mesylate (DEM) (author's transl)]

Changes in tension of spiral strips of saphenous, femoral and external carotid arteries and veins were measured isometrically. DEM stimulated 6 preparations in almost the same concentration ranges (pD2 values were 8.64 to 8.40). However, the dose-response curves for DEM indicted variations in responsiveness among the different arteries and veins. Compared with norepinephrine (NE) (1)( the intrinsic activity of DEM was 0.002 on saphenous arteries, 0.05 on saphenous veins, 0.03 on femoral arteries, 0.18 on femoral veins, 0.13 on external carotid arteries and 0.13 on external carotid jugular veins. Thus DEM contracted more potently the venous strips from the hind limbs. IN femoral and external carotid arteries, antagonism of serotonin by DEM or methysergide was investigated. DEM displaced the dose-contractile response curves for serotonin in a noncompetitive manner, and the antagonistic response of DEM to serotonin was about 8 times more effective in external carotid arteries (pD'2 value=6.96) than in femoral arteries (pD'2 value=6.05). Methysergide, unlike DEM, antagonized the response to serotonin in a competitive manner at low doses but in a noncompetitive manner in high doses, and was fairly equal in antagonizing response to serotonin in external carotid arteries (pA2 value=that the therapeutic value of DEM in the treatment of orthostatic hypotension is due to its selective anti-serotonin activity on the external carotid arteries.