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Biomedical subjects

A Shimada

Publications and source records attributed to A Shimada.

At least 235 records · Page 13Linked to original sources
PubMed1992

An encephalomyelopathy in related Birman kittens.

The clinical and morphological features of an encephalomyelopathy in five related Birman kittens are described. The five kittens showed hind limb paresis and ataxia which progressed to hind limb paralysis. Four of the kittens had bilateral nuclear cataracts. Histological examination revealed diffuse lesions within the brain and spinal cord, especially within the thoracolumbar spinal cord. The major changes were foci of spongy change and vacuolation along with Wallerian degeneration. All kittens were inbred and an inherited aetiology was suspected.

Journal Article↗
PubMed1992

Inbred SAM-P/10 as a mouse model of spontaneous, inherited brain atrophy.

We developed a novel inbred strain of mouse with age-related brain atrophy and it was named "Senescence Accelerated Mouse (SAM)-P/10." Macroscopic morphometry indicated that the brains of SAM-P/10 showed age-dependent involutional changes mainly in the frontal portion of the cerebrum. The brain weight decreased by 8.6% throughout the life-span. There were no obvious defects in postnatal development. Semi-macroscopic morphometry revealed a prominent atrophy in the neocortex, olfactory cortex and amygdala. Microscopic morphometry showed that the neocortical neurons were lost with aging, with mostly the large neurons being affected which were lost by 35.6% throughout the life-span. Somata of the neocortical neurons shrank with advancing age. In a control SAM-R/1 strain with only a slight macroscopic involutional change in the brain without weight loss, neither loss of the neocortical large neurons nor shrinkage of the neocortical neurons was evident with aging. Learning and memory skills were evaluated using the one-trial passive avoidance task and conditional avoidance task. Young SAM-P/10 mice performed well in both tasks but older SAM-P/10 showed a poorer performance in both tasks, and this was even poorer than the performance of very old SAM-R/1 mice. Thus, SAM-P/10 can serve as a spontaneous animal model of brain atrophy for a variety of studies of aging of the brain. A better understanding of neurodegenerative diseases with dementia should be forthcoming.

Aging↗
PubMed1992

Hepatic encephalopathy associated with acquired portosystemic shunts in a dog.

An 8-month-old dog with a history of gastrointestinal disturbances and neurological signs was presented with hyperammonemia. Necropsy revealed ascites, portosystemic collaterals, and an irregularly surfaced small liver. Histologically, there were diffuse neuronal necrosis and focal spongiform changes in the brain, and marked fibrosis in the liver. Hepatic encephalopathy was diagnosed.

Animals↗
PubMed1992

A pathologic and bacteriologic study on otitis media in swine.

A pathologic and bacteriologic study on otitis media in swine was performed on 237 swine, ranging in age from 1 day to 1 year. These 237 swine from eight selected farms were slaughtered due to unfavorable prognosis associated with clinical signs of illness. One hundred sixty-three (68.8%) of the 237 swine were found to be affected with otitis, though only a few swine showed clinical signs characteristic of the disease. One hundred fifty-one (63.7%), 53 (22.4%), and 39 (16.5%) had lesions in the middle, external, and internal ear, respectively. Of the 151 cases with otitis media, bilateral and unilateral infection accounted for 114 (75.5%) and 37 (24.5%), respectively. Only 5/53 swine with otitis externa and 6/39 swine with otitis interna failed to show otitis media. All swine with infection in the tympanic cavity had inflammatory lesions in the auditory tube. Examination of the swine grouped by age revealed that, regardless of age, incidence of otitis media was 50-70%. In swine younger than 1 month old, otitis media tended to center on the auditory tube, where a mild infiltration of neutrophils into the mucous membrane was frequent. Thereafter, otitis media increased in degree and extent with age. Forty (26.5%) of the 151 swine affected with otitis media were accompanied by a substantial amount of inflammatory exudate in the tympanic cavity and bulla. Purulent exudate was found in 20/40 (50%) swine. Severe otitis media prevailed in swine between 1 and 4 months of age, showing inspissation of a suppurative exudate in the tympanic cavity and lysis of the underlying osseous wall of the tympanic bulla with subsequent fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomyces↗
PubMed1992

Topographic relationship between senile plaques and cerebrovascular amyloidosis in the brain of aged dogs.

The distributions of senile plaques (SP) and cerebrovascular amyloidosis (CA) were studied by employing thioflavin S and modified Bielschowsky stains, and beta-protein immunohistochemistry on serial sections of the brains of aged dogs older than 10 years. Mature and perivascular plaques, both of which contained compact amyloid deposits, always showed a close topographic relationship to CA. In contrast, the majority of diffuse plaques showed no topographic relationship to CA. Cell bodies of neurons and/or glia were almost always involved in the diffuse plaques. In addition, beta-protein immunohistochemistry demonstrated amyloid deposits on the periphery of occasional neurons. These findings suggest that different mechanisms may be involved in the development of the different subtypes of SP in the brains of aged dogs.

Aging↗
PubMed1992

An outbreak of copper poisoning in Mute swans (Cygnus olor).

Eight of 9 Mute swans (Cygnus olor) untied in the river acrossing the central part of Tottori-city died within the period of 40 days of summer in 1989. Seven of 8 Mute swans were pathologically examined. In all swans many yellowish-brown to greenish-brown granules were found in the cytoplasm of hepatocytes. The granules were intensely stained with rhodanine copper stain, schmorl method, and Berlin blue stain. Ultrastructurally, many lysosomes increased in size and density in the cytoplasm of hepatocytes. Other three swans, that died at other places, were served as controls. In control swans, many brown granules intensely stained with schmorl method and Berlin blue stain were also found in hepatocytes, but the number of rhodanine-positive granules were fewer than those of the affected cases. X-ray qualitative analysis showed three peaks corresponding to copper, zinc and sodium in the liver of the affected and control swans. Quantitative analysis demonstrated that mean hepatic copper concentration of the affected group was significantly higher than that of control group (P less than 0.01). From these findings, we concluded that all of 7 Mute swans died of copper poisoning.

Animals↗
PubMed1992

An immunohistochemical and ultrastructural study on age-related astrocytic gliosis in the central nervous system of dogs.

The pattern of astrocytic gliosis (AG) was examined in 2-month-old to 18-year-old dogs using glial fibrillary acidic protein (GFAP) immunohistochemistry and electron microscopy. Coronal sections from various levels of the central nervous system (CNS) were stained with hematoxylin & eosin, Luxol Fast Blue, Nissl, and Bodian in addition to GFAP. A consistent pattern of age-related AG was observed in the dogs. The white matter, cortico-medullary junction, and subcortical nuclei in the cerebrum, central nuclei in the cerebellum, various nuclei in the brain stem, and grey matter of the spinal cord showed even and intense GFAP staining. AG was also prominent in the cerebral and cerebellar cortices and thalamus. Moderate AG was observed in the hippocampus and white matter of the cerebellum and spinal cord. Electron microscopy demonstrated increased number of profiles of degenerative neural components in the vicinity of hypertrophic astrocytes in the cerebral cortex of the aged dogs. Moderate to severe AG was consistently shown in the CNS of the aged dogs. In contrast, young normal dogs showed minimum amounts of GFAP-positive astrocytes in the CNS. These findings suggest that the observed AG in the CNS of the dogs is a morphological expression of aging.

Aging↗
PubMed1992

Visual evoked potentials in guinea pigs with brain lesion.

Visual evoked potentials (VEPs) were recorded in 10 adult male guinea pigs with brain lesion. Lesions were produced in 5 animals by superficial suction of the occipital lobe. The other 5 animals were orally administered with hexachlorophene (about 35 mg/kg/day) for 28 days. In the VEP following the ablation of the occipital lobe, the peaks P10, N20, P55, N75, N140 and P200 disappeared in many cases. The amplitude of the peak N40 decreased to approximately one half its control VEP. In the VEP obtained from the animals administered with hexachlorophene, the peak latencies of N20, P30, P55, N75 and P100 were slightly prolonged after the 7th day following the first administration. On the other hand, there was no change in the latency of N40 during the whole period of administration. The peak-to-peak amplitude showed some variability in different peaks. Histologically, diffuse status spongiosis were found in the white matter of the cerebrum, cerebellum, and brain stem. As described above, the ablation of the occipital lobe caused markedly depressed VEPs, however, the responses to the photic stimulation persisted after the injury. On the other hand, the VEPs of animals administered with hexachlorophene showed a high probability of peak appearance, and a decrease in amplitude was not marked.

Animals↗
PubMed1992

[Irritable bowel syndrome in adolescence].

We studied seventy patients, 23 males and 47 females with irritable bowel syndrome in adolescence aged 13-19 yrs, who visited the department of psychosomatic medicine in Takano Hospital during about six year period of April, 1986-July, 1992. Takano Hospital is a coloproctological center in Kumamoto. In the clinical pattern of adolescent patients with irritable bowel syndrome the "gas" pattern was dominant (51.4%). Patients with the gas pattern have severe symptoms of flatus, fullness, rumbling sound and abdominal pain as well as bowel dysfunction, constipation and diarrhea in a classroom. Next, the diarrheal pattern occurred in 20.0%. Diarrheal patients complained of frequent bowel movements and retention feelings before attending school. Recurrent abdominal pain-like pattern was found in 7.1% patients. Clinical symptoms in the adolescent patients seem to derived from a mental tension and stress in a close classroom or before attending school. Many adolescenct patients (67.1%) with irritable bowel syndrome are embarrassed in school-maladjustment; leaving class early, late coming, a long absence, and a withdrawal.

Adolescent↗
PubMed1992

Apolipoprotein(a) is present in urine and its excretion is decreased in patients with renal failure.

To investigate the relation between renal function and concentrations of lipoprotein(a) [Lp(a)] in serum, we measured Lp(a) in samples of serum and urine from patients with diabetes mellitus and in samples sent to a laboratory center for measurements of creatinine clearance. Serum Lp(a) concentrations were significantly increased in subjects with obvious renal dysfunction (serum creatinine > or = 176.8 mumol/L) compared with normal control subjects. Urinary Lp(a) excretion was decreased in subjects with obvious renal dysfunction compared with subjects without obvious renal dysfunction (serum creatinine < or = 88.4 mumol/L) and was negatively and positively correlated with serum creatinine and creatinine clearance, respectively. More than 80% of urinary Lp(a) was recovered in the d > 1.21 kg/L fraction. At least six bands for apolipoprotein(a) [apo(a)] fragments, which were smaller than native apo(a) in serum, were observed in urine by immunoblotting, and some of these were also detected in serum. Degraded apo(a) fragments are probably present in urine, and their excretion decreases in parallel with decreases in the glomerular filtration rate.

Adult↗
PubMed1992

[An experimental study on the appropriate proportion of dopamine and dobutamine for mixed infusion to treat cardiopulmonary dysfunction].

This study was aimed to investigate appropriate proportion for combined use of dopamine (DA) and dobutamine (DB) to treat cardiopulmonary dysfunction. The total dose of 10 micrograms.kg-1.min-1 with several different proportions in steps of 2 micrograms.kg-1.min-1 of DA and DB was administered to mongrel dogs with intact lung and with cardiopulmonary dysfunction caused by lung edema induced by oleic acid instillation. The hemodynamic variables during and after the infusion with the combined dosages of both agents were compared with that of baseline values. In dogs with intact lung, cardiac index (CI) increased significantly in all proportions of both agents. The levels of CI tend to increase prominently when the proportion of DB in the mixture was increased. Heart rates showed a tendency to increase with higher proportion of DB. Increasing proportions of DA caused a more increase of arterial pressure than by increasing that of DB. In dogs with pulmonary edema, these hemodynamic characteristics with the proportional changes of both drugs were demonstrated more significantly than in normal dogs. From these results, it was concluded that the appropriate combined preparation of both agents to increase CI without extreme tachycardia in dogs with cardiopulmonary dysfunction was the mixed solution of DA 2-4 micrograms.kg-1.min-1 and DB 6-8 micrograms.kg-1.min-1.

Animals↗
PubMed1991

Modified Bielschowsky and immunohistochemical studies on senile plaques in aged dogs.

Aged dogs developed senile plaques (SP) in the brain which were similar to those occurring in aged humans. These SP were studied with a modified Bielschowsky stain and immunohistochemical methods using polyclonal antibodies raised against beta-protein and glial fibrillary acidic protein (GFAP). Serial sections stained by immunohistochemical and modified Bielschowsky stains showed that all areas of slight beta-protein immunoreactivity were intensely stained by the modified Bielschowsky stain. Most SP were observed in the neocortex of the cerebrum. Plaque densities were highest in the cingulate and temporal cortices. There were occasional SP in the subcortical nuclei including the caudate nucleus and putamen, and hippocampus. Based on the morphological characteristics demonstrated by the modified Bielschowsky stain, SP in the brains of the dogs were grouped into 3 types: diffuse, mature and perivascular plaques, of which diffuse plaques were predominant. Various degrees of astroglial reaction were observed in all subtypes of SP except diffuse plaques. These findings indicate that dog may serve as a model for study of the pathogenesis of SP.

Aging↗
PubMed1991

Control region and gastric specific transcription of the rat H+,K(+)-ATPase alpha subunit gene.

The rat gastric H+,K(+)-ATPase alpha subunit gene was cloned and the nucleotide sequence of its 5'-upstream region was determined. Sequence comparison with the corresponding part of the human gene indicated the presence of highly conserved regions which may be important for specific transcription of the alpha subunit in gastric parietal cells. The amino-terminal sequence (Met-Gly-Lys-Ala-Glu-) of the rat enzyme was similar to those of the pig and human enzymes. The gene organization of the rat enzyme was also similar to that of the human gene: introns 1, 2 and 9 were located in exactly the same positions as those in the human gene, and, as in the latter, exon 6 was not separated by an intron. The sequences of introns 1 and 2 were highly conserved among the rat, human and pig genes, but were entirely different from those of Na+,K(+)-ATPase catalytic subunit genes. Northern blot hybridization indicated that the gene was transcribed only in gastric mucosa.

Adenosine Triphosphatases↗
PubMed1991

Development of a possible nonmammalian test system for radiation-induced germ-cell mutagenesis using a fish, the Japanese medaka (Oryzias latipes).

To develop a specific-locus test (SLT) system for environmental mutagenesis using vertebrate species other than the mouse, we first established a tester stock of the fish medaka (Oryzias latipes) that is homozygous recessive at three loci. The phenotypic expression of these loci can be easily recognized early in embryonic development by observation through the transparent egg membrane. We irradiated wild-type males with 137Cs gamma-rays to determine the dose-response relationships for dominant lethal and specific-locus mutations induced in sperm, spermatids, and spermatogonia. Through observation of 322,666 loci in control offspring and 374,026 loci in offspring obtained from 0.64-, 4.75-, or 9.50-Gy-irradiated gametes, specific-locus mutations were phenotypically detected during early development. These putative mutations, designated "total mutation," can be recognized only in embryos of oviparous animals. The developmental fate of these mutant embryos was precisely followed. During subsequent embryonic development, a large fraction died and thus was unavailable for test-crossing, which was used to identify "viable mutations." Our medaka SLT system demonstrates that the vast majority of total mutations is associated with dominant lethal mutations. Thus far only one spontaneous viable mutation has been observed, so that all doubling calculations involving this endpoint carry a large error. With these reservations, however, we conclude that the quantitative data so far obtained from the medaka SLT are quite comparable to those from the mouse SLT and, hence, indicate the validity of the medaka SLT as a possible nonmammalian test system.

Animals↗
PubMed1991

Observation of the development of tolerance to and physical dependence on barbital by cortical evoked potential in rats.

To observe the dispositional and functional tolerance to and physical dependence on barbital, the influence of repeated administration of the drug on serum barbital levels, coordinative motion, body weight, and cortical evoked potential was assessed. Rats administered the first dose of barbital showed marked impairment of gross behavior and then loss of the righting reflex. While they were repeatedly treated with barbital for a 4-week period, the CNS depression became weaker and weaker, and loss of the righting reflex was no longer observed. Serum barbital levels after administration of barbital tended to decrease by the 28th day of repeated drug administration. Coordinative motion was markedly impaired after administration of the first dose, but gradually recovered during the repeated administration period. Barbital at 100 mg/kg, i.p., prolonged the latent time of the evoked potential in normal untreated rats but not in tolerant rats. During the withdrawal period, no particular change was observed in the animals' gross behavior. However, body weight loss and shortening of the latent time of the evoked potential were observed at 60 to 72 hours of withdrawal. These results suggest that cortical evoked potential can serve as a useful method for observing tolerance to and physical dependence on barbital.

Animals↗