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Biomedical subjects

Y Tazawa

Publications and source records attributed to Y Tazawa.

At least 73 records · Page 4Linked to original sources
PubMed1991

Using Healon to identify the lumen of the sac in dacryocystorhinostomy.

Sodium hyaluronate (Healon) injected into the lacrimal sac, facilitates a full-thickness cut of the lacrimal sac in cases in which it is difficult to identify the lumen of the sac. The sodium hyaluronate does not stain tissues, is effective for hemostasis, and is easily irrigated. A full-thickness cut of the lacrimal sac is required to ensure exact mucosal suturing in dacryocystorhinostomy. However, in cases involving a hypertrophic sac wall, a small lumen of the sac, or earlier perforation of the sac, it is sometimes difficult to identify the lumen during surgery. We describe how sodium hyaluronate, injected into the sac via a canaliculus, can facilitate identifying the lumen in this situation.

Dacryocystorhinostomy↗
PubMed1991

[Production of IL-6 and IL-1 alpha by human corneal epithelial cells].

By using enzyme-linked immunosorbent assay (ELISA), it was demonstrated that cultured human corneal epithelial cells produced interleukin-6 (IL-6) without any stimulation. As lipopolysaccharide (LPS)-stimulation did not induce further production of IL-6 and IL-1 alpha, it was suggested that IL-6 was produced naturally as in the case of IL-1 alpha production which has been previously reported by the author. Production of IL-1 alpha and IL-6 in the human corneal epithelial cells may play a role in amplifying immune responses on the ocular surface.

Adult↗
PubMed1990

An acute form of tyrosinemia type I with multiple intrahepatic mass lesions.

The acute form of tyrosinemia type I usually causes severe hepatocellular dysfunction. We report a 4-month-old infant with hepatosplenomegaly, ascites, and multiple intrahepatic mass lesions mimicking hepatoma. A marked increase of serum alpha-fetoprotein (97.6 micrograms/ml) and multiple small low-density lesions in the liver demonstrated by computed tomography suggested the presence of hepatoma. The liver specimens obtained at laparatomy showed mixed nodular cirrhosis with fatty metamorphosis. Serum levels of tyrosine (6.6 mg/100 ml) and methionine (5.9 mg/100 ml) were increased. Urinary organic acid analyses disclosed increased excretions of succinylacetone (1,330 mg/g creatinine) and delta-amino-levulinic acid (113.6 mg/g creatinine). Histological abnormalities and biochemical evidences led to the correct diagnosis. This case emphasizes the need for complete investigations of puzzling cases and warns against undue reliance on noninvasive imaging techniques.

Amino Acid Metabolism, Inborn Errors↗
PubMed1990

Subclinical liver dysfunction in one-month-old infants with a low activity of vitamin K dependent coagulant factors assessed by normotest.

To clarify features of late vitamin K deficiency hemorrhagic disease in Japanese infants, seventeen of 1,687 infants screened by normotests were examined for signs and symptoms suggesting hepatobiliary diseases. Clinical observations disclosed findings suggesting hepatobiliary diseases in 7 of the 17 selected infants with normotest values of less than 40%, and 11 infants had abnormal results in one or more liver function tests. Taken together, 14 of the 17 infants had findings suggesting hepatobiliary diseases. Upon vitamin K supplementation normotest values improved in various degrees in all infants, whether or not they had signs or symptoms of hepatobiliary diseases. Late vitamin K deficiency hemorrhagic disease of infancy may be related to subclinical hepatobiliary diseases.

Female↗
PubMed1990

[The relationship between amplitude and extent of detachment indicated by the ERG c-wave of rabbit eyes with experimental retinal detachment].

We recorded ERG b- and c-waves from rabbit eyes with experimental retinal detachment and investigated the relationship between amplitude of the ERG and extent of the detachment. Three different extents of detachment (20, 60, 100% of the fundus) were made in three different groups of rabbits. In all 3 groups, the amplitude of both b- and c-waves remarkably decreased 1 hour after detachment and recovered at 6 hours to values corresponding to the extent of detachment. At 12 hours, the b-wave amplitude remained at almost the same values at 6 hours, whereas the c-wave amplitude showed further reduction. It was suggested that functional disorder in undetached retina occurred earlier in the retinal pigment epithelium than in the sensory retina of the eyes in the acute stage of the retinal detachment.

Animals↗
PubMed1989

Cytomegalovirus infection in low-birth-weight infants with acute respiratory tract disease.

To determine a participation of cytomegalovirus (CMV) infection in acute respiratory tract disease (ARTD) of low-birth-weight (LBW) infants, specific antibodies against CMV antigens, IgG antibodies against early antigens of CMV (IgG EA) and IgM antibodies against membrane antigens of CMV (IgG MA) were analyzed. The frequency of IgG EA in patients with ARTD was higher than that in controls (46% vs. 32%), and the geometrical mean titer (GMT) of IgG EA in the patients was also higher than that in controls (50.2 vs. 20.1). Five of 15 ARTD patients had IgM MA, and the frequency was significantly higher than that of controls (33% vs. 1.3%, p less than 0.01). Eleven of 15 LBW patients with ARTD had a history of blood transfusions during the neonatal period, and 5 of them had significant IgM MA indicating active CMV infection. All 4 LBW patients without blood transfusion were negative for IgM MA. These results suggest a close relationship of CMV infection to ARTD of LBW infants, but it remains for further studies whether blood transfusion is a primary source of CMV infection in LBW infants.

Acute Disease↗
PubMed1989

Clinical application of indocyanine green angiography to choroidal neovascularization.

In order to evaluate the clinical usefulness of indocyanine green video-angiography (IA), the angiographic features of choroidal neovascular membranes (CNM) were investigated in 27 eyes with choroidal neovascular diseases by means of standard fluorescein angiography (FA) and IA. FA showed the existence of CNM in 21 eyes and IA demonstrated evidence of CNM in 19 eyes, as "fan, comb or spotty hyperfluorescence" in the early stage and "leakage" in the late stage. In 6 out of 19 eyes the existence of CNM was shown by IA, while FA failed to identify the precise location and size of CNM due to the masking effect of overlying turbid fluid, massive hemorrhage or a large amount of serous fluid. The results imply that IA has an advantage over FA in cases where FA shows only the sign of occult choroidal neovascularization, and that IA can be applied to neovascular maculopathy as a routine examination.

Choroid↗
PubMed1988

Electroretinogram c-wave and slow PIII of the rabbit: changes in peak time and amplitude under various stimulus durations.

Changes in peak time and amplitude of the direct current registered c-wave of the electroretinogram of the albino rabbit were investigated with various stimuli of duration ranging from 0.25 to 10 sec. The stimulus intensity was 500 lux at the surface of the cornea. Slow PIII was isolated by administrations of sodium iodate and sodium aspartate. The peak time of the c-wave was longer than that of the slow PIII in the range of stimulus duration less than 3.5 sec, but peak times were almost the same in the range above 3.5 sec. The amplitude of the c-wave at peak was larger than the corresponding amplitude of the slow PIII in the range less than 1 sec, but the slow PIII became larger than the c-wave at more than 1 sec. For stimuli less than 4 sec, the smaller the stimulus duration, the smaller was the negative slow PIII which affected the height of the c-wave. We conclude that in order to minimize the influence of the slow PIII on the c-wave, the duration of stimuli with intensity of 500 lux for recording the c-wave of the rabbit should be less than 4 sec.

Animals↗
PubMed1988

Incomplete congenital stationary night blindness: electroretinogram c-wave and electrooculogram light rise.

Three cases of congenital stationary night blindness are reported. In all patients a negative electroretinogram was recorded by single bright flash stimulation and changed to positive on sequential reduction of the stimulus intensities. Oscillatory potentials were recognized. Biphasic dark adaptation curves and moderate elevation of the relative logarithmic final threshold of dark adaptation were also found. Values of critical flicker fusion frequency were reduced to a mild or moderate extent. VEP latency was prolonged beyond the normal range in two cases. In all three the electroretinogram c-wave was extinguished despite a normal electrooculogram light-dark ratio. It is hypothesized that in congenital stationary night blindness some disorder may exist in the apical membrane of the retinal pigment epithelium but not in the basal membrane in view of dissociation between the c-wave response and the light rise in the electrooculogram.

Child↗
PubMed1988

Ultrastructural abnormalities in the skeletal muscle of children with chronic cholestasis and a long-term vitamin E replacement.

We investigated the effects of long-term oral and intramuscular vitamin E repletion in children with chronic cholestasis. Clinical improvement or suppression of neuromuscular involvement after adequate vitamin E repletion was demonstrated. Light and electron microscopic abnormalities of the skeletal muscle, however, did not completely disappeared despite the correction of the biochemical abnormalities for more than 3 years. The muscle fibers showed less variety of pathologic features than before vitamin E repletion. Inclusions observed in the skeletal muscle fibers before vitamin E treatment were still observed in subsarcolemmal cytoplasm and the perinuclear regions. They were more irregularly curved and consisted of various substances. Similar inclusions were also observed in Schwann cells, perineural cells, fibroblasts, pericytes, endothelial cells and smooth muscle cells of intramuscular vessels. Although the external lamina was not disrupted, separation of the external lamina from the plasma membrane and multilayered external lamina were often observed. The nerves among muscle fibers still showed degenerative features. Morphological changes of the skeletal muscle during vitamin E therapy have not so far been reported in cases of chronic cholestasis. We discuss the relationship of these findings to vitamin E replacement in children with chronic cholestasis.

Biopsy↗
PubMed1988

Cytomegalovirus infection in acute respiratory tract disease accompanying hepatitis in infancy.

To elucidate relationship between acute respiratory tract diseases (ARTD) accompanying hepatitis and cytomegalovirus (CMV) infection in infancy, 74 full-term inpatients with ARTD and 34 control patients without ARTD or hepatitis were subjected to this study. By determining specific antibodies to CMV, IgG early antigen (IgG EA) and IgM membrane antibody (IgM MA) which are markers of active CMV replication, the following results were obtained. Thirty-one (41%) of the 74 patients with ARTD and 12 of the 34 control group (35%) had significant IgG EA (greater than or equal to 1:8). The geometric mean reciprocal titer in the group with ARTD (1:33.0) was higher than that in the control group (1:15.3). On the other hand, while 6 of the 74 patients with ARTD (8%) had significant IgM MA (greater than or equal to 1:8), none of the control group had positive IgM MA. Out of the 74 patients with ARTD, 8 (10%) patients, all except one being younger than 2-month-old, also had hepatitis. Of the 8 patients with hepatitis, 6 (75%) had significant IgG EA. The geometric mean reciprocal titer of the patients with hepatitis was higher than that of the patients without hepatitis, the titer being 1:42.6 and 1:30.7, respectively. On the other hand, 3 of the 8 patients with hepatitis (37%) had significant IgM MA while only 3 of the 66 patients without hepatitis (4.5%) had IgM MA. The frequencies of IgM MA between two groups were significantly different (p less than 0.05). CMV infection may be involved in some infants with ARTD, particularly in younger infants with both of ARTD and hepatitis.

Acute Disease↗
PubMed1988

Nerve regeneration in cornea after penetrating keratoplasty in rabbit, with special reference to relationship between regenerating nerves and basal laminae.

The pattern of nerve regeneration in the grafted rabbit cornea was investigated by electron microscopy. Grafted corneas were excised 2, 7, 14 and 28 days after grafting, and processed for observation by conventional electron microscopy. In the normal, unoperated cornea Schwann cell basal laminae are, unlike those of ordinary peripheral nerves, discontinuous and fragmentary on the fibers coursing through the corneal stroma. In the early stage of regeneration, while numbers of regenerating axons extended through the Schwann cell columns of regenerating axons extended through the Schwann cell columns in the grafts, many other regenerating axons elongated as single fibers through the corneal stroma outside the Schwann cell columns. These single naked axons were later enveloped by Schwann cell cytoplasm, contributing to the overall dense irregular pattern of regenerated nerves in the grafted cornea. It was thought that the regenerating axons can extend throughout the stroma without the guidance of basal lamina tubes, making the corneal stroma a favorable environment for nerve regeneration.

Animals↗
PubMed1987

Projections of extraocular muscle primary afferent neurons to the trigeminal sensory complex in the cat as studied with the transganglionic transport of horseradish peroxidase.

The central projections of extraocular muscle primary afferent neurons were examined in the cat by means of transganglionic axonal transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP). Injections of the extraocular muscle with WGA-HRP resulted in transganglionic terminal labeling within the ipsilateral trigeminal sensory complex. Although the density of trigeminal projections varied among cases, labeled axons and terminals were heavily and consistently found within the rostroventral portion of the pars oralis of the spinal trigeminal nucleus. The caudal part of the trigeminal principal sensory nucleus occasionally contained moderate labeling but very few deposits of HRP reaction product were noted in the pars interporalis and pars caudalis of the spinal trigeminal nucleus.

Animals↗
PubMed1987

Olfactory input to the lateral hypothalamus of the old world monkey.

Responses of lateral hypothalamic neurons to 8 odors were studied in chronic unanesthetized old world monkeys (Macaca irus). Many neurons (54.5%) responded to a single odor only, and the number of neurons responding to 2, 3 and 4 odors decreased successively. No neuron responded to as many as 5 odors. Thus, the presence of olfactory input and a highly discriminative ability for odors were found in the lateral hypothalamic area (LHA). Neuronal responses to the same odors were also studied in the septum (Spt). In anesthetized old world monkeys, evoked potentials were recorded in the LHA and in areas of the Spt and the nucleus accumbens (Acc) during stimulation of the olfactory bulb (OB). When the Spt (and probably the Acc with it) was subsequently destroyed, OB-evoked potentials in the LHA disappeared. Next, by injecting horseradish peroxidase (HRP) into the LHA, an olfactory pathway to the LHA was examined. Labeled neurons were found mainly in the Spt and the Acc, and only partly in other areas. However, labeled neurons were scarcely found in the prepyriform (PPF)-entorhinal (ER) area or in the olfactory tubercle (OT). The present study thus shows that an olfactory pathway to the LHA passes through the Spt and probably also the Acc, but not through the PPF-ER areas nor through the OT in the old world monkey.

Animals↗
PubMed1987

Occurrence of both (25R)- and (25S)-3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acids in urine from an infant with Zellweger's syndrome.

Urine from a patient with Zellweger's syndrome was examined for bile acids after fractionation into three groups according to mode of conjugation. 3 alpha,7 alpha,12 alpha-Trihydroxy-5 beta-cholestanoic acid was the predominant bile acid of the unconjugated and glycine-conjugated bile acid fractions. Smaller amounts of cholic acid and 1 beta-, 6 alpha-, 24-, and 26-hydroxylated derivatives of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid were found in both fractions in similar proportions. The bile acid spectrum of the taurine-conjugated bile acid fraction was different from those of the other two fractions in the occurrence of two new compounds as the major constituents. These compounds were tentatively identified as two epimers at C-23 of 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestano-26,23-lactone, which were probably artifacts formed from the corresponding tetrahydroxycholestanoic acids during the procedures for extraction after hydrolysis. High-performance liquid chromatographic analysis revealed that 3 alpha,7 alpha,12 alpha-trihydroxy-5 beta-cholestanoic acid excreted into the urine as the unconjugated form consisted of a mixture of (25R)- and (25S)-isomers in the ratio of about 7:3.

Bile Acids and Salts↗