Magnetic resonance spectroscopy (MRS) allows the noninvasive study of metabolism in vivo. In order to further understand the time course of biochemical changes during cerebral infarction, we performed the MRS study with pathological analysis. The left middle cerebral artery (MCA) was occluded in spontaneously hypertensive male rats (SHR) by the method of Tamura et al. The spectra were obtained from the infarcted hemisphere by placing the surface coils over the left side of the calvarium. ³¹P and ¹H-MRS were performed at 3 hours, 24 hours and 7 days after MCA occlusion. Ischemic lesions caused by the left MCA occlusion extended into the parietal lobe and caudate putamen. After 3 hours of ischemia, vacuolated neurophils and shrunken neurons were observed. At 24 hours, these changes were severe. After 7 days, infiltration of monocytes and capillary hyperplasia were seen, and neurons had disappeared. At the acute stage of ischemia the phosphocreatine/inorganic phosphate (PCr/Pi) peak ratio decreased. After 7 days of ischemia, these changes became obscure. The intracellular pH (pHi) decreased after 3 hours of ischemia and recovered almost to the control level at 24 hours post ischemia. Alkalosis was apparent 7 days after ischemia. This alkalosis might be due to increased permeability of the deteriorated blood brain barrier. Although the lactate level was high 24 hours post ischemia, the pHi was almost normal. The N-acetyl-aspartate/creatine ratio decreased significantly from the acute stage of stroke. This decrease correlated with pathological changes. The correlation of the magentic resonance spectra with the histological results may opens aspects for monitoring stroke therapy and a new approach to tissue characterization. (J Nippon Med Sch 1997; 64: 131-138)

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Local anesthetics have been contained in various OTC drugs and the number of cases of allergic contact dermatitis due to local anesthetics has increased recently. Thirty-five hundreds and fourteen cases suspected of suffering from drug eruption or contact dermatitis were the subjects of this study during the 8 years from January, 1988 to December, 1995.
One hundred and thirty-eight cases, suspected of having allergic contact dermatitis were patch tested with topical medicaments including local anesthetics and 70 (50.7%) of them showed positive. In 49 of the 60 cases who reacted positively to anesthetics extensive patch tests with the individual ingredients of the products were carried out.
The local anesthetics causing positive reactions were as follows (in order of frequency): dibucaine hydrochloride (35 cases: 71.4%), ethyl aminobenzoate (12 cases: 24.5%), lidocaine hydrochloride (2 cases: 4.1%), and procaine hydrochloride (1 case: 2.0%). The number of patients displaying allergies to local anesthetics has increased, especially cases caused by dibucaine hydrochloride. And the total positive reaction rate to dibucaine hydrochloride in the patch tests was 3.7%, which was as high that to the well-known strong sensitizer PPDA (3.9%) and neomycin (2.9%). Forty-three cases sensitive to local anesthetics were also studied for cross-sensitivity. (J Nippon Med Sch 1997 ; 64: 139-146)

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Laminin-overlay to the culture of a human hepatocellular carcinoma cell line, HuH-7, resulted in changes in the cell behavior; suppression of the cell growth, conversion of the cell morphology, and the elevated secretion of cellular AFP in the culture medium, implying that the cells had undergone apparent differentiation in vitro. Together with the behavioral changes, the cells showed positive immunohistochemical staining of the anti-p 21/WAF 1 antibody over the cell nucleus and the amount of p 21/WAF-1 proteins was increased in the cells. p 53 protein was detected both in the control cells and the cells with the laminin overlay. These findings indicate that the laminin-dependent changes in the cell behavior are closely associated with the activation of the cyclin-dependent kinase inhibitor, p 21/WAF-1, and that? is uncoupled with the p 53 expression. (J Nippon Med Sch 1997; 64: 147-153)

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It is reported that chronic electrical stimulation of perforant path (PP) produces mossy fiber sprouting in dentate granule cells and as a result new reccurent excitatory circuits are formed. It has been assumed that the circuits are responsible for the well-known lowering in the threshold required to generate seizure discharges by the electrical stimulation. The assumption was tested in the present investigation. Current source density analysis of the field potential in the dentate gyrus was carried out in control (n=8) and kindled (n=10) rats under pentobarbital anesthesia during seizure discharges. The field potential was produced by stimulating the PP and recorded simultaneously from 10 sites which were 50 μm apart from each other. The field potential consisted of a monosynaptic excitatory postsynaptic field current (EPSC) in the middle molecular layer followed by a population spike current (PSC). In the kindled rats, following the EPSC and PSC, a late sink appeared in the supragranular layer (SGL). The amplitude of the SGL late-sink showed a positive correlation with the density of Timm granules (r=0.76). The latency difference between the onset of PSC and that of the SGL late-sink ranged from 0.5 to 1.5 ms. This suggested the possibility that the SGL late-sink is produced via the recurrent excitatory circuit newly formed by mossy fiber sprouting. The SGL late-sink, however, evoked no further firing in dentate granule cells. During 5 Hz PP stimulation for 10 s, the amplitude of SGL late-sink increased gradually at first, but later it decreased gradually and disappeared before seizure discharges produced. Accordingly, there was no evidence suggesting that the new recurrent excitatory circuit played any role in producing seizure discharges. During seizure discharges, the EPSC resembling the SGL late-sink appeared spontaneously only in the SGL and seemed to initiate repetitive synchronized-firing of granule cells in one of four kindled rats. The number of burst discharges and the duration of seizure discharges with the late sink, however, were not significantly different from those of seizure discharges without such a late skin. These results suggest that the newly formed recurrent circuit plays no essential role in decreasing the threshold required to generate seizure discharges or in developing them. (J Nippon Med Sch 1997 ; 64 : 154-162)

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We cloned two characteristic subclones from a human pancreatic carcinoma cell line, AsPC-1, according to their distinctive cell shapes; one an epithelial morphology and designated as "Beto-1" and the other a fibroblastic morphology and designated as "Fib-1". Fib-1 grew faster than Beto-1, but the growth rate of the cells on plastics was as high as that of the cells on the extracellular matrix extracts, matrigel. The pancreatic tumormarker proteins, α-amylase, insulin, CEA, POA, PP, and AFP, but not CA 19-9, were positive in both subclones. Type IV collagen, fibronectin, and laminin, were all positive in both subclones; furthermore, the integrin adhesion receptor molecules, α 2 β 1-subunit, α 5-subunit, and a 6-subunit, were also positive. The intercellular adhesion molecules, E-cadherin and ICAM-1, were detected in Beto-1 and Fib-1, respectively. Although both subclonal cells attached to type IV collagen, fibronectin, and laminin in a concentration-dependent manner. Beto-1 adhered most strongly to type IV collagen and Fib-1 attached most strongly to fibronectin. Beto-1 showed morphological differentiation on matrigel and in the tumor xenografts. Further, there was more fibroblast infiltration and type IV collagen production in Beto-1 tumor tissues, and more lymphocyte and neutrophil infiltration in tumors of Fib-1 which expressed ICAM-1 proteins. This study indicated that the histological diversity observed in the pancreatic carcinoma was evolved from the composition of the tumor cells which express the specific adhesion receptors. (J Nippon Med Sch 1997; 64: 163-171)

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Few morphological studies have been reported on fluid-percussion experimental models using mechanically induced severe brain injury have been reported. This study was initiated to evaluate microscopic and immunohistochemical findings in severe brain injury models using rats.
The experimental rats and the methods used were the same as described for a fluid-percussion model. Fluid-percussion models of traumatic brain injury were produce by rapidly injecting fluid volume into the epidural space of the temporal lobe. We used 5 rats which sustained various degrees of injury by high (7.0 atm), medium (5.6 atm) and low (3.5 atm) magnitudes of impact and sham control. The rats were sacrificed and perfused transcardially with buffer solution followed by 2.5% glutaraldehyde at intervals of 24 hours, 3 days, and 7 days, and there were normal and sham control groups. In this immunohistochemical study, monoclonal antibody to 70 kilodalton neurofilament subunit was used in a standard Avidin-Biotin Complex Kit (DAKO).
Microscopic findings revealed subarachnoid hemorrhage, lateral Illyd ventricular hemorrhage, and rarefaction and petechial hemorrhage of the local contusional lesion.
In the medium level injury, there was a marked petechial hemorrhage in the corpus callosum and subependymal area. In the high level injury, there was marked edema in the white matter of the ipsi-and contralateral cerebral hemisphere, and multiple petechial hemorrhage in the brain stem and cerebellum. Microscopic findings in the corpus callosum, subependyma and brain stem in the vicinity of petechial hemorrhage revealed a large number of axonal swellings, but in these specimens only a few typical axonal retraction balls were seen with Bodian and immunohistochemical stains.
In conclusion, this experimental model seems to simulate local and diffuse shearing injury, showing various morphological characteristics of diffuse axonal injury (J Nippon Med Sch 1997; 64: 172-175)

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