Resolution of homonymous visual field loss documented with functional magnetic resonance and diffusion tensor imaging.

A 68-year-old man developed right homonymous hemianopic paracentral scotomas from acute infarction of the left extrastriate area. He was studied over the ensuing 12 months with visual fields, conventional MRI, functional MRI (fMRI), and diffusion tensor imaging (DTI). As the visual field defect became smaller, fMRI demonstrated progressively larger areas of cortical activation. DTI initially showed that the lesioned posterior optic radiations were completely interrupted. This interruption lessened in time and had disappeared by one year after onset. fMRI and DTI are innovative measures to follow functional and structural recovery in the central nervous system. This is the first reported application of these imaging techniques to acute cerebral visual field disorders.     

EUS IN THE DIAGNOSIS OF ULCERATIVE COLITIS

The ultrasonograms of ulcerative colitis (UC) in active stage show hypoechoic changes of the colorectal wall from the mucosal layer to the deeper layers. These endoscopic ultrasound (EUS) changes of the wall recognized in active stage disappear or normalize in the stage of remission. When the stage of UC is exacerbated, the hypoechoic changes of the wall extend from the mucosal layer to the deeper layers with the increase of wall thickness. These EUS images of active UC are classified into the following types: UC‐M, thickening of the whole wall with the structure preserved; UC‐SM, hypoechoic changes reach the superficial portion of third layer with the thickening of whole wall; UC‐SM deep, hypoechoic changes reach the deeper portion of third layer with the thickening of whole wall; UC‐MP, hypoechoic changes reach the fourth layer with the thickening of whole wall; UC‐SS/SE, hypoechoic changes penetrate through the fourth layer with the thickening of whole wall. With the help of EUS we can demonstrate the severity of inflammation in UC. Moreover, in severe cases of UC, the treatment strategy including emergency surgery can be determined. EUS is a valuable method in the management of UC.     

Excitatory mechanism of deflationary slowly adapting pulmonary stretch receptors in the rat lung.

The excitatory responses of deflationary slowly adapting pulmonary stretch receptor (SAR) activity to lung deflation ranging from approximately -15 to -25 cm of H(2)O for approximately 5 s were examined before and after administration of flecainide, a Na(+) channel blocker, and K(+) channel blockers, such as 4-aminopyridine (4-AP) and tetraethylammonium (TEA). The experiments were performed in anesthetized, artificially ventilated rats after unilateral vagotomy. The deflationary SARs increased their activity during lung deflation and its effect became more pronounced by increasing the degree of negative pressure. During lung deflation the average values for the deflationary SAR adaptation index (AI) were below 40%. Intravenous administration of veratridine (50 microg/kg), an Na(+) channel opener, stimulated deflationary SAR activity: one maintained excitatory activity mainly during deflation and the other receptors showed a tonic discharge during both deflation and inflation. Despite the difference in deflationary SAR firing patterns after veratridine administration, flecainide treatment (6.0 mg/kg) blocked veratridine-induced deflationary SAR stimulation and also caused strong inhibition of the excitatory responses of deflationary SARs to lung deflation. Under these conditions, the average values for deflationary SAR AI were over 90%. The responses of deflationary SARs and deflationary SAR AI to lung deflation were not significantly altered by pretreatment with either 4-AP (0.7 and 2.0 mg/kg) or TEA (2.0 and 6.0 mg/kg). These results suggest that the excitatory effect of lung deflation on deflationary SAR activity is mediated by the activation of flecainide-sensitive Na(+) channels on the nerve terminals of deflationary SARs.     

Effects of Several Denervation Procedures on Distribution of Calcitonin Gene-Related Peptide and Substance P Immunoreactive in Rat Stomach

The effect of chemical deafferentation, vagotomy(VGX), and gangliosympathectomy (GSX) on the density offibers containing calcitonin gene-related peptide (CGRP)and substance P (Sub.P) in the rat gastric wall was studied. Chemical deafferentation bycapsaicin abolished the density of CGRP-immunoreactive(IR) fibers, not Sub.P-IR fibers. Ten days after VGX,the density of CGRP-IR or Sub.P-IR fibers in the mucosa was largely reduced, while no reductionof CGRP-IR and Sub.P-IR fibers was seen in submucosaland muscular layers. GSX significantly reduced thedensity of CGRP-IR fibers in the mucosa and caused a moderate decrease in the fibers in submucosaland muscular layers. Pretreatment with6-hydroxydopamine, a neurotoxin for noradrenergicnerves, did not affect the density of CGRP-IR fibers inthe gastric wall. The density of Sub.P-IR fibers in thegastric wall was not affected by GSX. These studiesindicate that the CGRP-IR and Sub.P-IR fibers in themucosa are susceptible to extrinsic nerve denervation compared with those in the submucosa and musclelayers, that a major portion of the CGRP-IR fibers inthe mucosa is of both vagal and spinal origin, and thata major portion of the Sub.P-IR fibers in the mucosa is of vagal origin. Furthermore, thepresent results support that CGRP-IR fibers, notSub.P-IR fibers, in the rat stomach arecapsaicin-sensitive.     

Contrast-enhanced intraoperative ultrasonography of small hepatocellular carcinomas

Nine patients with small hepatocellular carcinomas, ranging up to 2 cm in size (phi: 1.7 +/- 0.2 cm, mean +/- SD), have been encountered, and in two of these patients the cancer was not identifiable by intraoperative ultrasonography. Thus to achieve a better detection of such small hepatic cancers, enhanced intraoperative ultrasonography was tested. Detection by enhanced intraoperative ultrasonography proved successful in all cases. These preliminary results indicate the potential of carbon dioxide as a contrast agent to enhance intraoperative visualization of small liver cancers.     

Accommodative intraocular lens with spring action. Part 1. Design and placement in an excised animal eye

We designed an intraocular lens (IOL) with spring action, which we call the Spring IOL, with the idea of providing a slight but adequate accommodative power. The Spring IOL consists of two 6.0-mm optics, held 4.38 mm apart, and four flexible loops. The optics are made of polymethylmethacrylate (PMMA) and the loops of polyvinylidene fluoride. The lens's refractive power is provided by the anterior optic; the posterior optic acts as a footplate to restrict the anteroposterior movement of the anterior optic. By torsionally compressing the obliquely arranged loops, a 10.0-mm 3-dimensional IOL can be reduced to 6.0 mm and inserted in the capsular bag through a 3.5-mm capsular opening. Because the Spring IOL is made of the same materials as conventional IOLs, most of the problems hindering the development of a refilling material (which could also provide accommodation) are avoided. In this first report we discuss the design of the lens, the refractive theory involved, and our experience inserting it in an excised animal eye.     

Developmental toxicity potential of grayanotoxin I in mice and chicks

Developmental toxicity potential of grayanotoxin I (GTX I), a toxic diterpenoid contained in plants of the family Ericaceae, with sodium ionophore activity, was studied in mice and chicks. In mice, intraperitoneal injections of 1.5 mg GTX I/kg body weight of mouse for three consecutive days during the organogenetic period caused some dams to die, but neither embryotoxicity nor teratogenicity was detected. In chicks, a single injection of 0.1-1.0 microgram GTX I per egg into the extraembryonic coelom on day 1.5 or 2 of incubation, or into the amnionic cavity on day 3 or 4 of incubation induced neither embryotoxic nor teratogenic signs, but 10 micrograms GTX I per egg showed lethal effects when applied on each of those days.     

Age-related alterations in adenylyl cyclase system of rat hearts.

Cardiac membranes from 26-, 52- and 104-week-old Wistar rats were used to investigate the age-related alterations in the beta-adrenergic receptor-adenylyl cyclase system. The densities and affinities of beta-adrenoceptors did not change with aging. There were no significant changes in the total amount of stimulatory G-protein (Gs), and in Gs activity measured in a reconstitution assay using human platelet membranes. The major isoform of Gs alpha, however, changed from a 45,000 to 52,000 dalton peptide with aging. The total amount of pertussis toxin substrates (Gi2 and Go) decreased significantly with aging. This finding was supported by the fact that pertussis toxin-induced potentiation of adenylyl cyclase activity was markedly reduced in the aged group. The activity of catalytic protein assessed by forskolin-stimulated adenylyl cyclase activity was decreased at 104 weeks. On the other hand, GTP analogue-stimulated adenylyl cyclase activity was significantly potentiated in the same group. These results suggest that the decreased sensitivity to catecholamines observed in aged hearts is mainly due to a dysfunction of catalytic protein, and that decreased Gi activity partially compensates for this catalytic dysfunction.     

A case of bilateral blepharospasm responsive to edrophonium]

A case of bilateral blepharospasm who registered the efficacy of edrophonium was reported. The case is a 49-year-old female. She had been in good health until January, 1991 when she complained of difficulty in opening her eyes while driving. Thereafter the condition progressed to such a degree that she was unable to experience a comfortable life. Her blinking rate did not changed. The symptoms were triggered by stress or some physical action, such as walking or driving. They were attenuated by taking a bath, sleep or sedation. The severity of the symptoms varied during the day and from day to day. Neurological examination revealed bilateral spasms of the orbicular oculi muscles, and occasionally of the orbicular oris muscles, sternocleidmastoid muscles and the perinasal regions. Neither orolingual dyskinesia nor other involuntary movements were detected. Surface electromyography (EMG) disclosed tonic discharges mainly from the orbicular oculi muscles. The abnormal spasm disappeared with the injection of edrophonium chloride. The test for the serum antiacetylcholine receptor antibody was negative and a repetitive stimulation EMG showed no waning phenomenon. No thymoma or thymus abnormalities were detected by pneumomediastinography. A needle EMG revealed neurogenic change in the distal portion of the limbs. A single fiber EMG showed elongation of the jitter value and the blocking phenomenon. Although distigmine bromide was ineffective against the spasm, pyridostigmine bromide and the local injection of botulinum toxin were very effective.(ABSTRACT TRUNCATED AT 250 WORDS)