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Biomedical subjects

K Ichikawa

Publications and source records attributed to K Ichikawa.

At least 361 records · Page 20Linked to original sources
PubMed1989

[Sweating deficiency in myotonic dystrophy].

We evaluated local sweating function quantitatively in nine cases of myotonic dystrophy (MyD) aged 26 to 61 years (mean, 45.4 years) and 25 control subjects aged 24 to 71 years (mean, 50.1 years). MyD subjects were grouped into three clinical classes according to their severity (three mild cases; class 1, three moderate; class 2 and three severe; class 3). 10 mg of acetylcholine was injected intradermally on the dorsum of the foot. After stimulation the impressions of sweat droplets were obtained using vinyl silicon impression material and the number of sweat droplet impressions per square centimeter was counted and the diameter of each droplet was measured by an image processor using a microcomputer. The result showed statistically significant decrease in the number of sweat droplets in class 2 and 3 as compared with control group and class 1. The histogram of sweat droplet diameter disclosed tendency of progressive deficit in diameter in all three clinical classes of MyD. Various kinds of autonomic function test, besides sweat tests, and nerve conduction study done on class 2 and 3 failed to show any significant abnormalities. Skin biopsy study done on lower leg on four subjects of class 2 and 3 revealed atrophy of eccrine sweat glands. These results suggests that local sweating deficiency develops in MyD as the disease progresses and that this deficiency is caused by dysfunction of eccrine glands, and not of postganglionic autonomic nerves.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Expression of p21 ras protein in human melanoma cell lines.

Samples obtained from six human melanoma cell lines have been tested for the presence of p21 ras oncogene product by Western blotting analysis. The overexpression of p21 was detected in two cell lines out of the six samples. These DNA samples have not been shown to be transformants by transfection assay. Moreover, amplification or rearrangement of DNAs from these cell lines was not found by Southern blotting analysis. Northern blotting analysis, however, detected the expression of Ki-ras gene in RNA extracted from the two cell lines. Thus, it was suggested that the overexpression of p21 might be a result of increased normal mRNA transcript of Ki-ras gene.

Blotting, Northern↗
PubMed1989

[Adult polysaccharide storage myopathy].

A first Japanese case of an adult polysaccharide storage myopathy (APSM) was reported. A 30-year-old Japanese male was admitted because of weakness of the lower limbs. The onset of the symptoms was at the age of 23. Neurologically he had moderate weakness of proximal limb muscles involving the lower limbs more than the upper and slightly decreased vibratory sense in the feet. His gait was waddling. The following laboratory values were obtained; SGOT 45 I.U., SGPT 83 I.U., CPK 218 I.U., UA 8.3 mg/dl. Ischemic exercise test of the forearm showed a normal rise of venous lactate. EMG revealed a mixture of myopathic and mild neurogenic patterns characterized by motor units of short duration and low amplitude with intermittent high amplitude potentials, fibrillation and fasciculation. There were also prominent myotonic discharges without clinical myotonia. MCV was normal, however sural nerve SCV was slightly slow (lt. 36/m, rt. 38 m/s). Muscle biopsy revealed vacuolar myopathy. Most vacuoles contained basophilic, PAS-positive, diastase-resistant and Lugol's iodine-negative material. With ATPase staining there was type 1 fiber predominance (84%), but the vacuoles were predominantly seen in type 2A fiber. In ultrastructural study, the storage material was located under the sarcolemma and in the areas of the intermyofibrillar network. No delimiting membranes were seen. At higher magnification, these masses were consisted of filaments. Therefore the storage material was considered to be unusual polysaccharide. Glycogen storage disease was suspected, however, biochemical study of the muscle specimen disclosed no enzymatic defect including branching enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Analysis of hepatic hemodynamics by a new method of per-rectal portal scintigraphy using 99mTcO4- (direct intramural administration of radioisotope)].

To depict of porto-systemic collaterals clearly, and to analyze of hemodynamics of liver, we developed new method of per-rectal portal scintigraphy (direct intramural administration of 99mTcO4- by 23G needle). And we used this method in patient with liver diseases (acute hepatitis: 5, chronic hepatitis: 7, liver cirrhosis: 25 cases). From time activity curve of the liver and the heart, liver/heart ratio; index of porto-systemic shunt via inferior mesenteric vein (IMV) and first flow ratio(k); index of portal blood flow from IMV pathway/index of hepatic total blood flow were calculated. In our method, the images of portal vein, liver, heart, especially porto-systemic collaterals were visualized more clearly than enema methods. The liver/heart ratio was significantly lower in patients with liver cirrhosis than that in non-cirrhotic patients (p less than 0.01), which indicated that patients with liver cirrhosis had more porto-systemic collaterals than non-cirrhotic diseases. The k was more lower in liver cirrhosis than in acute hepatitis (p less than 0.01). And the k was also more lower in chronic hepatitis than in acute hepatitis (p less than 0.1), which indicated that portal blood flow via IMV reduced in early stage of chronic liver diseases. In conclusion, new method of per-rectal portal scintigraphy has more advantage for analysis of hepatic hemodynamics than enema methods.

Hepatitis↗
PubMed1988

Locations of medullary neurons with non-phasic discharges excited by stimulation of central and/or peripheral chemoreceptors and by activation of nociceptors in cat.

The activity of medullary neurons (146 units) with non-phasic discharges was recorded extracellularly in decerebrated, spontaneously breathing cats. The firing rate changes were studied during injections of 100% CO2-saturated saline into the vertebral artery and into the carotid artery. Thirty-nine of the 146 units were excited by the vertebral artery injections in the same time course as ventilatory augmentation. Eighteen of the 39 units did not react to peripheral chemoreceptor stimulation, i.e. they responded exclusively to central chemoreceptor stimulation. These 18 units were distributed in the caudal ('C') chemoceptive area of the ventral surface, in the vicinity of ventral respiratory group (VRG) neurons, and in the dorsal area ventral to the solitary tract. Twenty-one of the 39 units were excited by peripheral chemoreceptor stimulation, i.e. neurons with integrations of central and peripheral chemoreceptor inputs. They were densely packed in the nucleus paragigantocellularis lateralis, although also found in and around the rostral VRG neurons. Fifty-one of the 146 non-phasic units were excited (44) or inhibited (7) immediately after the vertebral artery injections, and their discharges returned to pre-injection levels prior to or during the early period of ventilatory augmentation. They also reacted to skin pinching, i.e. neurons with nociceptive action, and were found scattered variously in the ventral half of the medulla. Fourteen of the 146 units reacted to both chemoreceptor and nociceptor stimulations. The remaining 42 units were non-responsive. In summary, the distributions of the tonically active neurons excited by the central and/or peripheral chemoreceptors were not restricted to the ventral surface of the medulla.

Action Potentials↗
PubMed1988

Binding of thyroid hormone receptor-associated factors to rGH gene 5' flanking sequences.

Binding of semi-purified rat liver triiodothyronine (T3) nuclear receptor (T3-nR) to sequences in the 5' flanking DNA of rat growth hormone (rGH) has been evaluated by the DNAse-footprinting technique. T3-nR was obtained by extraction in 0.3 M KCl and partially purified by column chromatography to 80 pmol/mg T3 maximal binding capacity (MBC). The T3-nR preparation protects the sequence -330 to -314 (5'-CAGTGAACAAACGATG-3') which may represent a repressor element, the sequence -224 to -192 (5'-CATTGCCCATAAACCTGAGC-3') which is thought to involve positive T3 regulation, the sequence -98 to -78 (5'-GCTCCAGCCATGAATAAATG-3') which may regulate basal expression, and the TATA box area. Although the DNAse footprints occur only with preparations containing functional T3-nR, it is uncertain whether each protected zone is due to binding of T3-nR or associated proteins. Protection is associated with enhanced DNAse digestion around the protected sites, involves both strands, and does not appear to require T3 occupancy of the receptor. Only the areas described are protected in the studies, and non-specific proteins such as albumin, core histones, and nuclear extracts without receptor activity, have no effect. A putative consensus enhancer sequence -CCAGAGCCAAGG- conveying T3 responsivity is suggested on the basis of comparison to sequences in four T3 responsive genes.

Animals↗
PubMed1988

Studies of neurocirculatory effects of long-term L-threo-3,4-dihydroxyphenylserine administration in a patient with familial amyloidotic polyneuropathy.

The case is reported of a 57-year-old woman with familial amyloidotic polyneuropathy and concomitant orthostatic hypotension for which L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) was clinically effective. Testing of autonomic function under telemetric intra-arterial pressure monitoring before and during L-threo-DOPS treatment clearly demonstrated the pathophysiology of the sympathetic nervous system and its modification by L-threo-DOPS.

Amyloidosis↗
PubMed1988

Rapid and transient excitation of respiration mediated by central chemoreceptor.

We evaluated rapid and transient changes in phrenic nerve (PN) and internal intercostal (IIC) activities when 0.2-0.5 ml of saline saturated with 100% CO2 was injected into the vertebral artery during various respiratory phases in decerebrated spontaneously breathing cats. The injections evoked an initial transient inhibition of ongoing PN or IIC activity with a mean onset latency of 0.17 s, followed by excitation of subsequent respiratory activities with an onset latency ranging from 0.4 to 2.7 s; the average onset latency of expiratory excitation (1.49 s) was significantly longer than that of inspiratory facilitation (0.89 s). The initial inhibitory responses were analogous to reflex effects of injections of phenyl biguanide, indicating that the initial inhibition was due to activation of vascular nociceptors and the subsequent excitation was due to stimulation of the central chemoreceptors. In addition, CO2-saline injections during hypocapnic apnea developed a quick reappearance of respiratory rhythm, and the first facilitatory effect appeared in tonic IIC activity, which became more active before rhythm started. In summary, the present study, by use of a technique of vertebral arterial injections of 100% CO2-saline, revealed dynamic properties of respiratory control system mediated by central chemoreceptors and vascular nociceptors.

Animals↗
PubMed1988

The effects of upper incisor separation on the submandibular and sublingual glands of rats.

The effects of upper incisor separation on the submandibular and sublingual glands of rats were examined biochemically, immunohistologically, and radio-immunologically during 28 days of treatment. Lateral separation of the upper incisors by application of force from an orthodontic appliance caused significant enlargement of the sublingual and submandibular glands of rats by three and seven days, respectively, after the beginning of the orthodontic treatment. This enlargement was followed by a significant increase of both RNA and DNA content, with some evidence of hyperplasia and hypertrophy. The enlargement was also associated with a significant increase of substance P at early stages after treatment, suggesting the involvement of the sensory nerves. These changes were largely inhibited by phenoxybenzamine, an alpha-adrenergic blocker, but not by atropine or morphine. Wet weights and RNA contents of the sublingual glands were markedly reduced by atropine. In comparison with control animals, the enlarged submandibular glands of rats subjected to orthodontic treatment secreted additional proteins identical with those secreted by glands enlarged by chronic administration of isoproterenol. In addition, chemical sympathectomy with 6-hydroxydopamine and phenoxybenzamine stimulated the synthesis of these abnormal proteins, but atropine and morphine did not. In contrast, protease activities in the convoluted granular tubule cells in the submandibular glands were increasingly reduced after treatment, as seen in rats subjected to chronic treatment with isoproterenol. However, the submandibular and sublingual glands completely recovered after removal of the orthodontic appliance.

Animals↗
PubMed1988

Effect of thyroid hormone on the protein inhibitors for Ca2+-dependent proteinase in brain: evidence for the induction by thyroidectomy of irreversible changes in immature rats.

The effects of thyroid hormone on the levels of protein inhibitors for Ca2+-dependent proteinase were studied in rat brain. Four different inhibitory proteins (I, II, III, and IV) were isolated from immature (7-day-old) rat brain. The molecular weights of these inhibitory proteins, which were estimated by gel-exclusion chromatography on Sephacryl S-200 column, were approximately 280,000 (I), 70,000 (II), 50,000 (III), and 35,000 (IV). All of these inhibitory proteins were decreased by thyroidectomy. Four-day T4 administration (100 micrograms/kg daily) to thyroidectomized-immature animals restored proteins I, II, and IV. However, protein III was not recovered with the same treatment of the rats. In mature rats (40-day-old), four different inhibitory proteins were identified in the brain. The molecular weights were identical to those obtained in immature rat brain. As observed in immature rats, all of these inhibitory proteins were decreased by thyroidectomy. In contrast to the results obtained in immature animals, however, inhibitory protein III, as well as I, II, and IV, was restored by T4 administration (100 micrograms/kg daily) to thyroidectomized mature rats. The results suggested that thyroid hormone increases protein inhibitors for Ca2+-dependent proteinase in brain, and that irreversible decrease in one of the inhibitors is induced by thyroid hormone deficiency in immature animals. The phenomenon may be related to the neonatal hypothyroidism-induced irreversible damage to the central nervous system in patients with cretinism.

Aging↗
PubMed1988

Selective alterations of insulin actions by glucagon in isolated rat epididymal adipocytes.

Previously we demonstrated that glucagon inhibits high affinity insulin binding without influence on low affinity binding in rat adipocytes in vitro. In this study we investigated the effects of glucagon on insulin actions in adipocytes in vitro. Glucagon modified neither glucose oxidation nor lipogenesis stimulated by insulin. The antilipolytic action of insulin was decreased by preincubation of the cells with glucagon. Glucose transport enhanced by insulin was diminished by preincubation of the cells with glucagon. The decrease in antilipolysis was a lowering of the maximal response to insulin, whereas the decrease in glucose transport was a lowering of the sensitivity to insulin. These results suggested that glucagon does not necessarily inhibit all of the insulin actions, and that the mechanism of insulin stimulation of glucose transport, which is supposed to be mediated by glucagon-sensitive insulin receptor, is different from those of insulin-induced antilipolysis, glucose oxidation, and lipogenesis.

3-O-Methylglucose↗
PubMed1988

Antipituitary antibodies in patients with the primary empty sella syndrome.

The frequency of detection of serum antibodies against pituitary cells was determined in 32 patients with the primary empty sella syndrome. Antibodies reacting with corticotropin-secreting mouse AtT20 and PRL-secreting rat GH3 cells were found in 24 (75%) and 15 (47%), respectively, of the 32 patients; 14 patients (44%) had antibodies reacting with both cell lines. In patients with pituitary adenomas, the prevalence of antipituitary antibodies was significantly lower than in those with the empty sella syndrome; 1 of 9 acromegalic patients had antibodies reacting with GH3 cells, and 2 of 9 prolactinoma patients and 1 of 7 patients with nonfunctioning adenomas had antibodies reacting with both AtT20 and GH3 cells. Among 6 patients with idiopathic diabetes insipidus, 1 patient had antibodies reacting with AtT20 and GH3 cells, and 2 patients had antibodies reacting with either AtT20 or GH3 cells. None of 5 patients with established autoimmune diseases (3 with systemic lupus erythematosus and 2 with autoimmune adrenal failure) had antipituitary antibodies in their serum. These results suggest that pituitary antibodies may be related to the development of pituitary atrophy and the primary empty sella syndrome, and that the test may be clinically useful as a screening test for the empty sella syndrome.

Adolescent↗
PubMed1988

Effect of cisternal administration of acetazolamide on rapid excitation of central chemoreceptors.

We evaluated rapid and transient changes in phrenic (PN) and internal intercostal (IIC) activities when 0.5 ml of saline saturated with 100% CO2 was injected into the vertebral artery at the C1 level before and after cisternal administration of carbonic anhydrase inhibitor (acetazolamide) in decerebrated, spontaneously breathing cats. Before acetazolamide administration, the injections evoked an initial, transient inhibition of ongoing PN or IIC activity, followed by excitation of subsequent respiratory activities with a short onset latency of less than 3 sec. On the other hand, cisternal administration of acetazolamide abolished both the initial inhibition and the subsequent rapid excitation of respiratory activities, although there still existed a delayed, weak and prolonged excitation of respiration. These results indicated that hydration of CO2 accelerated by carbonic anhydrase within the brain would be essential for the rapid changes in respiratory activity mediated by the central chemoreceptors.

Acetazolamide↗
PubMed1988

Conformational transition of thyroid hormone receptor upon hormone binding: demonstration by aqueous two-phase partitioning.

An aqueous two-phase partitioning study of partially purified nuclear thyroid hormone receptor from rat liver was performed. Stability of 3,5,3'-tri-iodo-L-thyronine (T3)-receptor complex and T3-binding activity in the presence of dextran or polyethylene glycol were assessed in order to determine the amount of occupied or unoccupied receptors in each phase. Partition coefficients were calculated as the ratio of receptor concentration in the upper polyethylene glycol-rich phase H2O and that in the lower dextran-rich phase H2O. The partition coefficient was a sensitive function of the salt at pH above 6.1 and below 5.1. The salt had no effect on the partition coefficient at pH around 5.6. These results suggest that the isoelectric point of the thyroid hormone receptor is about 5.6, confirming previous determinations using isoelectric focusing. The partition coefficient of the receptor decreased upon T3 binding, regardless of the salt composition. In contrast, the partition coefficient of thyroxine-binding globulin increased upon T3 binding. Free T3 preferentially partitioned into the upper polyethylene glycol-rich phase and gave a partition coefficient higher than 1.0. These results strongly suggest that the decrease in the partition coefficient of the receptor upon hormone binding reflects conformational changes or changes in electrostatic properties of the receptor upon hormone binding. Such an alteration may be involved in biological activation of the receptor upon hormone binding.

Animals↗