Propagation of the Kakegawa strain of bovine coronavirus in suckling mice, rats and hamsters

The Kakegawa strain of bovine coronavirus was easily propagated in suckling mice. Infected animals died with nervous symptoms, and serial passage was readily accomplished by intracerebral inoculation with brain emulsions. The 3rd passage viral material from infected mice evoked the same disease in suckling mice, rats and hamsters inoculated by the intracerebral or by the subcutaneous route. Viruses recovered from mice, rats and hamsters could be clearly differentiated from mouse hepatitis virus strain 2 by the neutralization test.

Effect of hypertension on blood-brain barrier. Change after restoration of blood flow in post-ischemic gerbil brains. An electronmicroscopic study

The effect of induced hypertension on the blood-brain barrier (BBB) change in Mongolian gerbils exposed to various periods of ischemia was studied. Evans blue dye was used to determine the BBB change in animals subjected to different levels of hypertension after 3 h ischemia. Horseradish peroxidase (HRP) was used in electronmicroscopic studies of animals subjected to 30 min, 1, 3 or 6 h ischemia and subsequently exposed for 30 min to varying periods and sequences of normo- and hypertension. Furthermore, HRP-labeled vesicle counts were performed in animals from the 30-min ischemia group. Our findings revealed that hypertension, after blood flow restoration following ischemia, induces and/or accelerates BBB damage by enhancing endothelial vesicular and/or tubulo-channel transport.

Transient appearance of "no-reflow" phenomenon in Mongolian gerbils

We investigated the existence of the "no-reflow" phenomenon in focal cerebral ischemia. Regional cerebral blood flow was studied in Mongolian gerbils perfused with a carbon-black particle suspension after cerebral ischemia prior to decapitation and compared with 14C-antipyrine autoradiographic images. The correlation between the occurrence of the "no-reflow" phenomenon and systemic arterial blood pressure change was also examined. We found that the phenomenon was transient in character and that its manifestation was related to the transient fall in arterial blood pressure observed immediately after clip release and with stagnation of venous blood flow. The phenomenon disappeared in animals in which the arterial blood pressure was artificially increased after clip release.

Effect of steroid on ischemic brain edema. Analysis of cytotoxic and vasogenic edema occurring during ischemia and after restoration of blood flow

Mongolian gerbils were observed for the effects of beta-methasone on ischemic brain edema which developed during ischemia or after blood flow restoration. The severity of brain edema was determined by measuring water content of the ischemic cerebral hemisphere, using the wet and dry methods. Sodium and potassium ions were extracted from homogenized brains with 0.75N HNO2 and ion concentration measured by flame photometry. Passage of RISA from blood into the cerebral parenchyma, as an indicator of blood-brain barrier change, was determined with a gamma-scintillation counter. In the cytotoxic edema model, animals were killed after 9 h permanent ischemia or 3 h after 1 h ischemia. In the simultaneous cytotoxic and vasogenic edema model, the animals were killed either 20 h or 3 days following 1 h ischemia, or 3 h after blood flow restoration following 6 h ischemia. Steroid treatment was ineffective in ischemic brain edema of the cytotoxic or vasogenic type.

Serological relation between calf diarrhea coronavirus and hemagglutinating encephalomyelitis virus

Neutralizing (NT) and hemagglutination-inhibiting (HI) antibodies to calf diarrhea coronavirus (CDCV) and hemagglutinating encephalomyelitis virus of swine (HEV) (strain 67N) were detected in high proportions of normal adult cattle and pigs in Japan. Since comparison of NT and HI titers in the serum samples suggested in antigenic difference between the viruses, cross NT and HI tests of these viruses were carried out with antisera raised in rabbits. The homologous NT titers were markedly higher than the heterologous titers. In HI tests essentially the same results were obtained. These findings indicate the presence of a marked difference in antigenic make-up between CDCV and HEV. NT and HI tests can clearly differentiate the viruses, although there is some cross reaction.

[Pediatric metrizamide CT cisternography and CT ventriculography (author's transl)]

We have studied the diagnostic value of computed tomography with metrizamide CSF enhancement in 37 infants. According to the method of injection, we called CT cisternography, CT ventriculography and CT cystography. These methods were useful for the morphologic and dynamic evaluation of the CSF pathways. We used them especially for the evaluation of hydrocephalus, skull base tumor, infantile subdural hematoma and its allied diseases, or congenital cystic lesion such as Dandy-Walker syndrome. The side effects in children are much less than those in adults.

Brain edema during ischemia and after restoration of blood flow. Measurement of water, sodium, potassium content and plasma protein permeability

The left cerebral hemisphere of Mongolian gerbils was used to elucidate the mechanisms of brain edema which develop during cerebral ischemia and after restoration of cerebral blood flow following temporary ischemia. Water content was measured by the tissue-drying method. Sodium and potssium ion concentration was measured by flame photometry. Passage of 131I-albumin (RISA) from blood to the cerebral parenchyma was measured on a gamma scintillation counter. Our findings indicate that pure cytotoxic edema develops during ischemia and during a short period after restoration of cerebral blood flow. Vasogenic edema, which is accelerated by the leakage of plasma constitutents from blood due to blood-brain barrier damage, developed after restoration of the cerebral blood flow. After less than 1 hr of ischemia, restoration of the cerebral blood flow drastically reduced the degree of brain edema. However, restoration of the cerebral blood flow greatly worsened the brain edema following more than 3 hr of ischemia.

Cerebrospinal fluid cytology after subarachnoid hemorrhage

A method is described which has been found capable of detecting subarachnoid hemorrhage (SAH) up to 15 to 17 weeks after its occurrence. The episode of SAH was confirmed by bloody and/or xanthochromic cerebrospinal fluid (CSF) at the time of SAH onset. In this study, 47 samples of lumbar CSF from diagnostically confirmed SAH patients were used. The CSF cells were collected onto slides and stained with May-Gruenwald-Giemsa or Perl's reagent. Iron-positive cells were detected at 1 week, increased by 4 to 6 weeks to 8.5% of total nucleated cells, and decreased to 1% by 15 to 17 weeks. All 27 samples obtained at 2 to 9 weeks after SAH showed iron-positive cells. No iron-positive cells (false-negative samples) were noted in 25% (one of four) of samples obtained during the first week, and in 33% (one of three) of samples obtained 10 to 12 weeks and 15 to 17 weeks after SAH. Of the total samples (37) obtained within 17 weeks after SAH, 8.1% (three of 37) were false negative. No iron-positive cells were detected in samples obtained later than 21 weeks after the SAH episode (10 samples).

Electron microscopy of Akabane virus

Electron microscopy of negatively stained purified virus and of thin sections of infected cells and tissues showed Akabane virus being similar in morphology and morphogenesis to members of the family Bunyaviridae.

Modification of periventricular hypodensity in hydrocephalus with ventricular reflux in metrizamide CT cisternography

An analysis of metrizamide computed tomography (CT) cisternographic findings in cases of communicating hydrocephalus has been carried out. Serial observations of the density in the periventricular area in 19 cases with metrizamide ventricular reflux have revealed the following different patterns: (a) precontrast periventricular hypodensity diminishing after CT cisternography and possibly indicating transependymal metrizamide migration (two cases); (b) periventricular hypodensity unchanged (two cases); (c) minimal periventricular hypodensity with slight rise in its attenuation values after ventricular metrizamide reflux (four cases); and (d) no periventricular hypodensity and no change after reflux (six cases). Our preliminary experience indicates that the presence of periventricular hypodensity with an increase in its attenuation values following ventricular reflux of metrizamide is possibly a criterion that may be used in favor of a cerebrospinal fluid shunting operation.

[Metrizamide CT cisternography in skull base tumors (author's transl)]

Twenty-three cases suspected of skull base tumors were examined by CT cisternography (CTC) with CT scanner (EMI 1010) from April, 1977 to March, 1978. The lesions in 20 cases were diagnosed as positive and confirmed by operation and/or autopsies. These include five acoustic neurinomas, six pituitary adenomas, two craniopharyngiomas, two skull base meningiomas, one arachnoid cyst and miscellaneous tumors. Isotonic Metrizamide solution four of 2-10 ml was injected via lumbar route. Patients were kept in 30 degrees Trendelenburg position for 60 minutes until the first scanning. Scannings were obtained 1, 3, 6, 24 and in some cases 48 hours after lumbar injection. No side effects except for headache, nausea, vomiting occurred. There were no convulsions. In diagnosing cerebellopontine angle tumors, the indirect signs such as asymmetrical ambient cisterns are of importance, when combined with direct signs, i.e. a shadow defect. Parasellar tumors are usually difficult to diagnose with conventional CT due to streak artifact caused by adjacent bony structure. In CTC the extrasellar extension of pituitary tumors were clearly visible. The size, shape, dimensions and the relationship to the adjacent structures of the craniopharyngiomas were easily demonstrated with CTC especially when a coronal view was added. In arachnoid cyst, CTC demonstrated the delayed turnover of Metrizamide between the cyst cavity and the adjacent subarachnoid space. In conclusion, CTC is an useful neuroradiological diagnostic adjunct because of minimal bony streak artifact and high spatial resolution. It would be expected that small tumors of even 2-3 mm in diameter might be diagnosed, from the fact that the middle cerebral artery in the suprasellar cistern is clearly visible as a shadow defect.

[Significance of computed tomography in therapeutic diagnosis of brain tumors (author's transl)]

Because of its noninvasive property of direct imaging of the size and shape of the lesion, CT scan is significant not only for the diagnosis of the brain tumors, but also for the assessment of its chronological and/or therapeutic change in size. Contrary to the conventional cerebral angiography and contrast encephalography, CT scan is feasible to detect the tumor repeatedly at short intervals. From March 1976 to October 1977, 197 cases of brain tumors were examined by CT, 6 tumors (1 pineal tumor, 2 cerebellar vermian tumors and 3 supratentorial tumors) of which were radiated after the initial CT scan and re-examined by CT at every 400-1,000 rads radiation, and their grade of radiosensitivity could be evaluated. Immediately after the radiation of 400 rads for five days to the large pineal tumor of a 16-year-old boy, CT exactly showed the markedly diminished size of the tumor, and the tumor disappeared on CT after the 4,000 rads radiation. Cerebellar vermian tumors suspected of medulloblastoma were also diminished in size on CT after the 600 rads radiation. One supratentorial tumor was radiosensitive and disappeared at the end of radiation therapy. Other supratentorial tumors were not changed on CT during the radiation. Procedures for the therapeutic diagnosis, when combined with CT, can easily indicate whether the tumor is radiosensitive or not, without any invasive examination and/or operation.