The radiologic assessment of vessel wall thickness.

A method allowing accurate and repeated measurements of vessel wall thickness has been developed. It consists of permanent opacification of the outer wall with tantalum in conjunction with magnification angiography. The technique was tested in a model, in human saphenous vein specimens, and in long-term experiments in rabbit blood vessels. Eighteen rabbits underwent exploratory surgery, after which the abdominal aorta, inferior vena cave, and the femoral and carotid arteries were coated with tantalum paste. Subsequently, magnification angiograms were performed from one to 14 months later. The wall thickness ranging between 100 and 300 micron was clearly visualized. While no gross inflammatory or foreign body reaction was seen, small granulomata adjacent to the blood vessels were frequently identified. The method described can be valuable in studying the natural history of the atherosclerotic process, particularly the behavior of vascular grafts.

Effect of exposure to nitrogen dioxide on alveolar macrophage-mediated immunosuppressive activity in rats.

Nitrogen dioxide (NO2), a major component of air pollutants, induces inflammatory responses in the lungs. Resident alveolar macrophages (AM) play an immunosuppressive role in the lungs via suppression of lymphocyte proliferation, and nitric oxide (NO) plays a crucial role in this immunosuppressive activity. Microenvironmental changes within the alveoli during inflammatory responses, however, can inhibit this immunosuppressive activity of AM. The present study was designed to clarify the effect of NO2 exposure on the immunosuppressive activity of and NO production by AM in rats. Wistar rats were exposed to 10 ppm NO2 for 3, 14 or 28 days, after which bronchoalveolar lavage fluid (BALF) was taken as a sample of the alveolar microenvironment. Suppression of concanavalin A-induced lymphocyte proliferation and NO production by AM were markedly inhibited by BALF from NO2-exposed rats (NO2-BALF). The inhibitory effect of NO2-BALF at 28-days exposure was stronger than that of NO2-BALF at 3 or 14 days exposure. In conclusion, AM-mediated immunosuppressive activity was inhibited by the NO2-induced changes of the alveolar microenvironment through the inhibition of NO production.

[Neuroradiological Evaluation of an experimentally implanted tumor into cerebral hemisphere of neonatal beagles (author's transl)].

Twenty-five neonatal beagles were used for this study. Gliosarcoma was injected into the cerebral hemisphere of 7 neonatal beagles (Group I). These animals were then treated by boron neutron capture therapy. The response of the tumor to therapy was evaluated by serial CT scans and 3 times magnification of cerebral angiography. The animals were sacrificed at varying post-therapy periods for histological study. Fifteen neonatal beagles implanted gliosarcoma without therapy (Group II) and 3 normal controls without tumor (Group III) were subjected to the same follow-up studies. (Results) (1) Neonatal beagles with implanted tumor showed moderate degree of ventricular dilatation within a short period. The finding of communicating hydrocephalus was interpreted as initial growth of tumor. (2) Animals after therapy had variable cavitation in the hemisphere that had contained calcium deposit on CT. Moderate dilatation of the lateral ventricle was present without any significant midline shift and there was an area of porencephaly extending out from the right lateral ventricle on CT (Fig. 1, Case 2). Cerebral angiography demonstrated hydrocephalus with an avascular region in the right cerebral hemisphere, compatible with the previously described porencephalic cyst (Fig. 2, Case 2). (3) Three cases out of 7 showed neurological symptoms after tumor implantation (Cases 3, 5 and 6). Carotid angiography showed large temporal lobe tumor with some tumor stain and also some involvement of the right frontal lobe after therapy (Fig. 7, Case 3). In postmortem examination, there was tumor seen coating the right lateral ventricle as well as the left temporal horn. The right cerebral hemisphere was slightly smaller than the left. The left lateral ventricle was remarkably enlarged (Fig. 9). (4) Four out of 7 treated animals with injected gliosarcoma showed no evidence of tumor at postmortem examination. CT demonstrated moderate dilatation of the lateral ventricle without any significant midline shift, an area of porencephaly and definite decrease in size of the right cerebral hemisphere and calvarium (Fig. 4). (5) Fifteen neonatal beagles implanted gliosarcoma without therapy (Group II) developed symptomatic and died within two weeks. (6) Control animals showed no ventricular dilatation or other abnormalities. (7) Microscopic examinations showed no similarities between implanted gliosarcoma and human glioblastoma. (Conclusion) Serial CT scans and magnification cerebral angiography in this experimental model appear extremely helpful in following the effects of therapy and important tool for the evaluation of a tumor growth or regression.

[Experimental studies on tumor implanted into cerebrospinal fluid: with special reference to tumor growth].

The incidence of metastasis to another organs of the intracranial tumors is rare, while the intracranial dissemination of brain tumor is often experienced clinically. For this purpose of the formation and growth of the intracranial tumor dissemination, VX2 carcinomas implanted into cisterna magna of 24 New Zealand rabbits are studied by neuroradiological and pathological methods. Twenty-one out of 24 (87%) had tumors intracranially. Nineteen cases out of 24 rabbits developed intraventricular tumors selectively. Two cases without the development of tumors showed moderate dilated lateral ventricles. Thiry-seven percent of implanted tumor cases were demonstrated by 3 times magnification cerebral angiography. While CT presented 67 percent of tumors indicating about two times higher detection than magnification cerebral angiography. From the result of these experiment, the detection of tumors by CT was two times higher than the magnification angiography.

[Endocrinopathy due to intracranial aneurysm (Part I)--Direct kinetic effect of aneurysm on the hypothalamo pituitary system (author's transl)].

Intracranial aneurysm rarely causes endocrinopathy clinically, however, many laboratory data show abnormality concerning endocrine function. To elucidate the reasons of these endocrine dysfunction, the authors investigated several representative patients in our department and the reported cases. The major part of reported cases suggests that the direct kinetic effect of aneurysms on the hypothalamopituitary system resulted in the endocrinopathy. The common features are described as follows. 1) Aneurysm were of large size. 2) Most aneurysms were located at the intracranial internal carotid artery. 3) They had no previous history of SAH usually. 4) Visual impairment was one of the common manifestation among them. 5) The higher frequency of the reported pituitary dysfunction in laboratory examination was shown in the following turn. However, some of our cases did not always agree with the reported ones. SAH operation etc. were considered to be the reasons of this discrepancy.

[Anatomical asymmetries of the frontal and parietal lobes (author's transl)].

The anatomical asymmetries of the cerebral hemispheres were described by several investigators. These evaluations were done in postmortem condition. With the introduction of the CT scan, the cytoarchitecture of the human brain in vivo are well appreciated. The purpose of this study is to demonstrate the functional and anatomical asymmetries on the frontal and parietal lobes.

Arteriovenous shunting in the lymph node before and after antigenic stimulus.

We have assessed the effects of antigenic stimulation on the regional blood flow of the lymph node. In seventeen New Zealand white rabbits, the regional blood flow to the popliteal lymph nodes was determined using 9 and 15 micron microspheres at 16, 40, and 144 h following antigen administration. The regional blood flow in the resting lymph node measured with 15 micron spheres was 0 . 46 +/- 0 . 07 ml g-1 min-1, with 9 micron spheres 0 . 26 +/- 0 . 03 ml g-1 min-1. There was a significant 'differential flow' (the difference in blood flow between the experimental and control nodes) measured with 15 micron spheres (P less than 0 . 05). This increase in blood flow was larger early (16 h) than late (144 h) following antigen administration (P less than 0 . 01). There was significant (P less than 0 . 05) 'shunt flow' (the difference in blood flow measured with 15 micron and 9 micron spheres) in the lymph node, with more shunting early (16 h) than late (144 h) following antigen administration. No significant shunting was seen in the kidney or thigh muscle. Thus, we have established: (1) a significant increase in blood flow following antigenic stimulus; (2) shunting of 9 micron microspheres in the resting popliteal lymph node; (3) increased shunting following antigenic stimulus; and (4) that the increase in nodal blood flow was, to a large extent, secondary to increased shunt flow. Both the increased blood flow and the shunting shortly after antigenic stimulus may be important in the evolution of the immune response.

Crystal structure of a decamer RNA r(ggcggucgcu)2 with terminal and tandem G x U wobble base-pairs.

The data set of the crystal structure of a self-complementary RNA duplex r(ggcggucgcu)2 with terminal and tandem G x U wobble base-pairs has been collected to 2.3 A resolution. Crystals belong to the tetragonal space group P4(1)2(1)2 or P4(3)2(1)2; a = b = 50.0 A, c = 102.7 A, and alpha = beta = gamma = 90 degrees, with two duplexes in the asymmetric unit. The structural analysis using the MAD method is currently in progress.

Ultrasound directed placement of needles into brains of rhesus monkeys.

Gray scale ultrasound identified the lateral and third ventricles, basal ganglia, columns of the fornix, and the suprasellar optic system of monkeys with craniotomy defects. Needles were placed in these structures under ultrasound guidance. Radiographs and formalin fixed brain sections confirmed the expected position of the needle tracts.

Experimental arterial aneurysms:modification of the production technique.

Vein pouches obtained from the external jugular vein were used to create experimental aneurysms on the carotid arteries of 13 rabbits and the abdominal aortas of 18 rabbits. Eighteen of these vein pouch aneurysms were grafted onto a linear incision in the artery; 13 of the aneurysms were grafted onto an elliptical incision. In 4 of the rabbits in which the vein pouch was grafted onto an elliptical arteriotomy in the carotid, a new approach for producing an intracranial aneurysm was attempted by relocating the aneurysm segment to the subarachnoid space at the cranial vertex. The results indicate that the aneurysms grafted onto an elliptical arteriotomy had a higher patency rate than the aneurysms grafted onto a linear arteriotomy in both the aortic and carotid models. Also, the attempt to produce an intracranial model demonstrated that short-term patency of the aneurysms could be achieved and that a two-stage approach to creating such aneurysms would be more appropriate than a one-stage approach.