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Biomedical subjects

Y Sakashita

Publications and source records attributed to Y Sakashita.

15 recordsLinked to original sources
PubMed1992

Hereditary motor and sensory neuropathy with calf muscle enlargement.

We report three related patients with autosomal dominant hereditary motor and sensory neuropathy (HMSN). An unusual and characteristic feature was calf enlargement, caused by muscle fiber hypertrophy predominantly of type 1 fibers. None of the family members showed atrophy of the legs. Sural nerve pathology disclosed marked loss of myelinated fibers and numerous onion bulb formations. While cases of HMSN with calf muscle hypertrophy have been reported, the present pedigree was different from that in any of the previous cases in that no family member showed clinically apparent leg atrophy.

Adolescent↗
PubMed1992

Studies on endogenous formation of N-nitroso compounds in the guinea pig supplemented with proline or thioproline and sodium nitrate.

The endogenous formation of N-nitrosoproline (NPRO) and N-nitrosothioproline (NTPRO, N-nitrosothiazolidine-4-carboxylic acid) was studied by monitoring their excretion in the urine of guinea pigs given oral doses of 10 mg proline or thioproline after supplementation with 34 mg (0.4 mmol) sodium nitrate. In order to estimate the conversion of nitrate to nitrite, the animals were also supplemented with 3.5 mg (0.05 mmol) sodium nitrite instead of sodium nitrate. In animals fed commercial diets, the excretion of NPRO and NTPRO under supplementation with sodium nitrate was 2.0 micrograms and 28.7 micrograms/animal/day, respectively, whereas the excretion under supplementation with sodium nitrite was 0.7 micrograms and 13.3 micrograms/animal/day, respectively. The higher excretion of NTPRO than NPRO in each case shows that thioproline is more effective for nitrite trapping than proline. The animals supplemented with nitrate excreted more than twice the amounts of NPRO or NTPRO than those supplemented with nitrite. It is assumed, therefore, that more than 0.1 mmol nitrate is reduced to nitrite and takes part in the endogenous nitrosation of the guinea pig. When various concentrations of L-ascorbic acid (AsA), known to inhibit the formation of N-nitroso compounds, were also administered orally to animals immediately after supplementation with sodium nitrate, the NPRO excretion decreased with increasing AsA concentration. These data indicate that the guinea pig, which is unable to synthesize AsA as well as humans, may be an appropriate animal model for evaluation of the endogenous nitrosation ability of humans ingesting nitrate.

Animals↗
PubMed1992

[Unilateral persistent hyperhidrosis after ischemic stroke].

A 64-year-old right hemiplegic woman, who had been treated for hypertension for 15 years, was admitted to our hospital. Neurologic examination on admission disclosed right hemiplegia and motor aphasia; however, ophthalmoparesis, pupillary abnormality, and blepharoptosis were not evident. Excessive sweating on the right side of the body, which was most marked on the face, was observed. Amount of sweating on the left side of the body was normal. Unilateral hyperhidrosis persisted for more than 2 months. MRI revealed hemorrhagic infarctions in the left basal ganglia, internal capsule, thalamus, hypothalamus, and medial part of the cerebral peduncle. 123I-IMP SPECT disclosed hypoperfusion in the left striatum, thalamus, occipital cortex, and right cerebellar hemisphere. Cerebral angiography revealed arteriosclerotic changes in the basilar artery, but that the left posterior cerebral artery and its branches were not occluded. Unilateral persistent hyperhidrosis is rare after ischemic stroke. Hypothalamic lesion was thought to be responsible for the hyperhidrosis in this patient. As the hypothalamus receives its blood supply from the posterior cerebral artery, unilateral persistent hyperhidrosis may be an important sign of cerebral infarction in the posterior cerebral artery region.

Cerebral Infarction↗
PubMed1991

Visual attentional disturbance with unilateral lesions in the basal ganglia and deep white matter.

To elucidate the role of the basal ganglia and deep white matter in the visual attention mechanism, a new visual attention task was carried out by 15 patients, 9 with left-side and 6 with right-side basal ganglia and/or deep white matter damage without visual field defects, and by 12 normal subjects. Their reaction times were recorded in response to a random visual stimulation by pushing a button with the hand ipsilateral to the side of the lesion. All the patients with damage to the right side of the brain had a longer reaction time in the left space than in the right or middle space. With conventional test, only one of them showed left unilateral spatial neglect. Seven of the 9 patients with a left lesion had a significantly longer reaction time in the right space than in the left. None had unilateral spatial neglect. Both the right and left brain-damaged groups showed longer reaction times in both spaces, compared to the normal groups. There was no significant difference in reaction time among the control subjects. These findings suggest that the basal ganglia and deep white matter in each hemisphere play some role in directing visual attentional factors into both spaces. Visual attentional disturbance was highly evident even with left-side brain damage, and this kind of disturbance is not usually revealed with the current tasks used for testing unilateral spatial neglect.

Adult↗
PubMed1991

[A case of Behçet disease with transverse sinus thrombosis and successful treatment with colchicine].

A 64-year-old man was admitted to our hospital because of headache and fever. Four months before admission, he had suffered from thrombophlebitis of the legs, erythema, oral aphtha and genital ulcers, and was diagnosed as having Behçet disease. Several days prior to admission he developed fever and was treated with enoxacine, which caused disorientation and abnormal behavior. These psychiatric symptoms disappeared after enoxacine was discontinued. On admission he was neurologically normal. Fever and headache disappeared spontaneously. However, he complained again of headache, and was suspected to have cerebral sinus thrombosis. Brain CT scan showed no abnormality, but brain MRI and cerebral angiography demonstrated right transverse sinus thrombosis and stasis. He was treated with colchicine, isosorbide, and ticlopidine. Because he had a gastric ulcer, corticosteroids were not indicated. Two months later, brain MRI demonstrated reduction of the size of the sinus thrombosis, and the clinical outcome was favorable. We would like to emphasize the usefulness of MRI and colchicine in the patient with Behçet disease complicated by sinus thromboses.

Behcet Syndrome↗
PubMed1990

Biochemical and physical analysis of subcellular membranes in rat parotid gland enlarged by chronic isoproterenol administration.

1. Chronic administration of isoproterenol caused similar alterations of membrane lipid profile in at least two rat parotid subcellular fractions, secretory granular and microsomal. 2. Typical changes in phospholipid classes and fatty-acyl chain groups were an increase of phosphatidylcholine and a decrease of sphingomyelin, and an increase of octadecadienoyl chain and a decrease of eicosatetraenoyl chain, respectively. 3. Electron spin resonance study showed that the isoproterenol-treatment also affected a membrane physical property, which may be through these compositional changes in membrane constituents.

Animals↗
PubMed1990

[Changes in the free fatty acid composition of rat salivary glands induced by chronic administration of isoproterenol].

The major constituent free fatty acid in rat parotid and submandibular glands was palmitic acid (about 40% of the total), followed by saturated and unsaturated fatty acids with 18 carbon atoms and arachidonic acid. The composition was changed by chronic administration of isoproterenol, with an increase of linoleic acid and a decrease of arachidonic acid coinciding with changes in the acyl composition of phospholipids. With respect to the metabolism of unsaturated fatty acids, delta 6-desaturation activity converting linoleic acid to gamma-linolenic acid was detected using [14C]linoleoyl-CoA in the submandibular gland. These results suggest that changes in the acyl composition of phospholipids induced by chronic administration of isoproterenol are in part due to changes in free fatty acid composition and that delta 6-desaturation activity may be involved in the regulation of unsaturated fatty acid composition.

Animals↗
PubMed1990

[Ultrafast CT scanner; preliminary experience in Japan].

We evaluated the usefulness of Ultrafast CT scanner C-100 (UFCT) in 30 patients' clinical practice. UFCT was very useful not only for cardiac studies but for other body organs' studies. Simultaneous multilevel ultrafast scans of UFCT enabled us to analyse cardiac ventricular motion not only by the ejection fraction but by the change of wall thickness. We could get ultra-early contrast phase images (within one minute images from contrast medium injection start) of contiguous 15, 1 cm interval levels by high quality single slice mode of UFCT. These ultra-early phase images and late phase images would be helpful for tissue characterization.

Adolescent↗
PubMed1989

Phospholipid metabolism in rat submandibular gland. Positional distribution of fatty acids in phosphatidylcholine and microsomal lysophospholipid acyltransferase systems concerning proliferation.

Rat submandibular gland phosphatidylcholine mainly consisted of the 1-saturated acyl-2-unsaturated acyl type. The high occupancy of unsaturated fatty acid at the C-2 position is in part explained by the preference of microsomal acyl-CoA:1-acyl-sn-glycero-3-phosphocholine (1-acyl-GPC) acyltransferase for unsaturated fatty acyl-CoAs. This enzyme activity was partially inhibited by divalent cations. Ca2+ may be important for regulation of a deacylation-reacylation cycle, suggested because Ca2+ is also known to activate the deacylation enzyme, phospholipase A2. Although the presence of 1-acyl-GPC acyltransferase activity is also observed in plasma membrane of the submandibular gland, the microsomal enzyme showed properties different from the enzyme in plasma membrane in terms of its susceptibility to neural salts and detergents. Cell proliferation caused by chronic administration of isoproterenol resulted in an increase of linoleic acid at the C-2 position of phosphatidylcholine. However, this alteration did not correlate with the changes of activity and substrate specificity of 1-acyl-GPC acyltransferase and the other C-2 acylation enzyme, 1-acyl-sn-glycero-3-phosphate acyltransferase, which suggests that the alteration of fatty acid by isoproterenol treatment is due to a change of supply of substrates or specific acyl breakdown of phosphatidylcholine.

1-Acylglycerophosphocholine O-Acyltransferase↗
PubMed1987

Magnetic resonance imaging of human cerebral infarction: enhancement with Gd-DTPA.

Five patients (1 female and 4 males) with cerebral infarction of 4 h to 27 months duration were studied 9 times with magnetic resonance (MR) using Gd-DTPA. Spin-echo (SE) MR images (MRI) were obtained before and after the administration of Gd-DTPA, and correlative CT scans were performed on the same day. In 2 cases, 4 h and 27 months after the ictus, there was no enhancement with Gd-DTPA. There was faint enhancement in 2 cases with cerebral infarction of about 24 h duration and obvious enhancement in all cases in the subacute stage. Compared with enhanced CT, MR using Gd-DTPA demonstrated more obvious enhancement of infarcted areas. MR enhancement using Gd-DTPA showed a gradual increase and the accumulated Gd-DTPA in infarcted areas slowly diffused to the periphery. MR enhancement with Gd-DTPA is similar to that of enhanced CT, but may be more sensitive in the detection of blood brain barrier breakdown.

Adult↗
PubMed1987

[Application of spinal dynamic computed tomography in the diagnosis of spinal cord arteriovenous malformations].

Seventeen cases of spinal cord arteriovenous malformation (AVM) were evaluated by use of spinal dynamic computed tomography (CT). In the intravenous injection method, contrast medium was injected bolusly into the median cubital vein. In the intraarterial injection method, contrast medium was injected slowly into the feeding artery. In both methods, lesions were demonstrated in all cases. Three-dimensional localization of the lesions were more clearly demonstrated in the intraarterial injection method. Intravenous injection method was useful in the postoperative follow-up study due to its noninvasiveness.

Adolescent↗