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Biomedical subjects

T Ichikawa

Publications and source records attributed to T Ichikawa.

At least 523 records · Page 29Linked to original sources
PubMed1987

Changes in hemodynamics due to the contrast medium during left ventriculography.

Seventeen patients with heart diseases examined by left ventricular angiography were divided into two groups consisting of those with a clinical history of heart failure (CHF+) and those without (CHF-). Changes in hemodynamics, circulating blood volume, and plasma volume due to injection of the contrast medium were studied, and the following results were obtained. Both the CHF- and CHF+ groups showed an increase in heart rate after injection of the contrast medium, but a statistically significant difference (p less than 0.05) was noted only at one and two minutes after angiography in both groups. Left ventricular systolic pressure decreased after injection of the contrast medium in both groups, but the CHF+ group required a longer time for recovery. In the CHF- group, the left ventricular end-diastolic pressure increased slightly after injection of the contrast medium, but in the CHF+ group it increased markedly with a statistically significant difference (p less than 0.01). Stroke volume, measured by a noninvasive, continuous cardiac output monitor according to the impedance method, increased upon injection of the contrast medium in the CHF- group. However, in the CHF+ group it decreased, although no statistically significant difference was noted in either group. Cardiac index increased markedly upon injection of the contrast medium in the CHF- group with a statistically significant difference (p less than 0.01), but hardly any change was observed in the CHF+ group.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1987

Androgen receptor, testosterone uptake and karyotype in androgen-dependent mouse tumor (SC 115) and its androgen-independent subline (CS 2).

Content of androgen receptor, retention of injected testosterone and karyotype of SC 115, androgen-dependent tumor, were compared with those of CS 2, an androgen-independent subline derived from SC 115. Although Bmax was less than that of SC 115, androgen receptor was present in the cytosol and the nuclear extract from CS 2. To examine the ability for androgen retention, a large amount of testosterone was injected into tumor-bearing mice, and the amount of androgen in the crude nuclear and postnuclear fractions of tumors was compared. In both fractions, retention of injected androgen was higher in the SC 115 than in the CS 2. Since most of the injected testosterone was not metabolized in the tissues and the injection of testosterone 5 alpha-reductase inhibitor showed no significant influence on the growth rate of the SC 115, intracellular active androgen was assumed to be testosterone in these tumor cells. As the CS 2 was tetraploid, the androgen independency of the CS 2 seems to be related to chromosomal changes.

Animals↗
PubMed1987

Effect of dietary taurine on cholesterol 7 alpha-hydroxylase activity in the liver of mice fed a lithogenic diet.

The effect of dietary taurine on hepatic cholesterol 7 alpha-hydroxylase activity was investigated in mice. At first, male ICR strain mice were fed a commercial non-purified diet for 4 weeks and killed at 01:00 h (midnight) or 13:00 h (daytime) and the cholesterol 7 alpha-hydroxylase activity in the hepatic microsomal fraction was measured. The enzyme activity was 5.9-fold higher at midnight than in the daytime. Next, to investigate the effect of dietary taurine on the activity of this enzyme, male ICR strain mice were fed semi-purified diets for 5 weeks: a cholesterol-free diet (standard), a lithogenic diet containing 0.5% cholesterol and 0.25% sodium cholate (C-CA), and a lithogenic diet supplemented with 5% taurine (C-CA + 5% taurine). All mice were killed at midnight and cholesterol 7 alpha-hydroxylase activity was measured. The enzyme activity of the mice fed the lithogenic diet was about 20% that of mice fed the standard diet. Dietary taurine increased the activity by 1.9-fold. Therefore, it was concluded that the inhibitory effect of dietary taurine on cholesterol gallstone formation was related to increased bile acid synthesis as reflected by stimulation of cholesterol 7 alpha-hydroxylase activity.

Animals↗
PubMed1987

[Studies on antibacterial activity of flomoxef and its distribution to serum and intraperitoneal exudate in surgery].

1. Bacteria detected in cases of acute abdominal ailments encountered in the first department of surgery at Hiroshima university and its related facilities during the recent 4 and a half years were reviewed and the antibacterial activities of flomoxef (FMOX, 6315-S) against these isolates were investigated. As a result, this antibiotic was found to show very high activities against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae and Proteus spp. 2. One gram of FMOX dissolved in 100 ml of physiological saline was administered by intravenous drip infusion during operation and its concentrations in serum and intraperitoneal exudate were determined. The intraperitoneal exudate concentration exceeded the serum concentration in 2 hours after the completion of the drip infusion and, reached high enough concentration to be effective against susceptible bacteria with MICs about 12.5 micrograms/ml. The above results suggested that the new cephem antibiotic FMOX for injection should be sufficiently effective against acute peritonitis.

Acute Disease↗
PubMed1987

A long-term cortical blindness after head trauma.

Here is a case of long-term cortical blindness after a head trauma. Its etiology is ascribed to the cerebral vascular occlusion caused by the head trauma. From the findings of both a computerized tomography (CT) and magnetic resonance image (MRI), the lesions of our case are assumed to be in the bilateral areas 17 (Brodmann), some part of the bilateral areas 18, 19 (Brodmann) and bilateral optic radiations. On determination of the areas of these lesions, the location of the lesion in the bilateral areas 17 has been especially done by using the MRI. The MRI findings in our case have a full significance on this point.

Adult↗
PubMed1987

[Pharmacokinetics in neonates and infants following administration of amikacin].

Sixteen neonates (at ages of 8 to 28 days) and 8 infants (at ages of 35 days to 1 year), who were in need of treatment with amikacin sulfate, were subjected to the present study. The drug was administered by intramuscular route (1.39 to 3.13 mg/kg) or by intravenous drip infusion over a 30 to 60 minutes period (2.94 to 6.00 mg/kg). Blood levels and urinary excretion of the drug were investigated with these subjects. The blood levels were also analyzed according to pharmacokinetic models. 1. When the drug was administered intramuscularly to neonates at average doses of 1.49 and 2.96 mg/kg and to infants at average doses of 2.97 mg/kg peak levels of 2.74, 6.53 and 8.55 micrograms/ml, respectively, were attained at 30 minutes after dosing. 2. When the drug was administered to neonates at average doses of 3.01 and 5.89 mg/kg by intravenous drip infusion over a 30 to 60 minutes period and to infants at average doses of 2.97 and 6.00 mg/kg in the same manner, peak levels of 7.70, 20.9, 9.40 and 23.0 micrograms/ml, respectively, were attained at the end of the intravenous drip infusion. 3. Urinary levels and recovery rates tended to increase with ages of these subjects. Urinary recovery rates for the neonates and the infants were 41.0 and 58.9%, respectively, on the average. 4. From a pharmacokinetic analysis of blood levels of the drug, it was concluded that, in any of the subjects who received the drug intramuscularly or by intravenous drip infusion, it would be possible to use the one-compartment open model. In the subjects who received the drug by intravenous drip infusion, however, it was determined the two-compartment open model would be the choice. 5. In the neonates and the infants, whose blood levels were analyzed according to the one-compartment open model, Ka values averaged 7.51 and 6.62 hr-1, respectively, with respective average Kel values of 0.32 and 0.66 hr-1. Average Vd values obtained were 0.36 and 0.26 L/kg, respectively. There was a negative correlation between the Vd values and the ages of the subjects, while there was a positive correlation between the Kel values and the ages. 6. Appropriate conditions for administering the drug by intravenous drip infusion to neonates and infants at ages of more than 1 week were investigated taking observed blood levels and achieved peak levels and trough levels calculated using the one-compartment open model into account.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1986

Color and spatial antagonism in the visual system of the larval swallowtail butterfly.

Many neurons exhibiting an antagonistic interaction between signals from one particular stemma (center) and neighboring stemmata (surround) were found in the second optic neuropil (medulla) of the larval swallowtail butterfly. Furthermore, most of the neurons showed a color opponent interaction in the center: combinations of opponent colors were blue vs green, UV vs green, and blue vs UV + green. Thus, photoreceptor signals are integrated into chromatically and spatially antagonistic mechanisms, even in the invertebrate.

Animals↗
PubMed1986

The commissural inhibition on secondary vestibulo-ocular neurons in the vertical semicircular canal systems in the cat.

The commissural inhibition on secondary vestibulo-ocular neurons (VOns) from the contralateral (c-) vertical canal system in the same geometric plane was studied in the anesthetized cat. The secondary VOns were identified by their orthodromic responses to stimulation of the ampullary nerves of the anterior (ACN) or posterior (PCN) semicircular canals and also by their antidromic responses to stimulation of the IIIrd and IVth nuclei. The majority of ACN-activated excitatory VOns in the descending and medial nuclei (32/36, 89%) and in the superior nucleus (20/23, 87%), received commissural inhibition from the c-PCN, while only few ACN-activated inhibitory VOns (3/35, 9%) in the superior nucleus received commissural inhibition from the c-PCN. On the other hand, all of the PCN-activated excitatory (50/50) and inhibitory (30/30) VOns in the vestibular nuclei received commissural inhibition following c-ACN stimulation.

Action Potentials↗
PubMed1986

Lymphocyte-associated viremia in varicella.

Varicella-zoster virus was isolated from mononuclear cells from seven immunocompetent children with varicella during the late incubation period and during the acute phase of the disease. The cells from which the virus was isolated were nonphagocytic and did not adhere to the surface of plates. The results indicate lymphocyte-associated viremia at the time of onset of varicella.

Adolescent↗
PubMed1986

Biliary excretion and enterohepatic cycling of glycyrrhizin in rats.

The enterohepatic cycling of glycyrrhizin was examined using rats with and without biliary fistulization. The plasma decay in the control rats without fistulization following an iv dose of 100 mg/kg of glycyrrhizin, was generally biphasic. However, secondary peaks were observed in all rats in the elimination phase, i.e., 0.5 to 12 h following dosing. The plasma concentrations in the rats with biliary fistulization administered the same dose showed a biexponential decline. The AUC and CLtot were significantly higher and lower in the control rats, respectively. The biliary excretion was 80.6 +/- 9.9% of the administered dose, and intestinal absorption was confirmed by using the bile collected after iv dosing. From these results, we concluded that glycyrrhizin was predominantly secreted from the liver into the bile, and that the secondary peaks in the elimination phase, the higher AUC, and the lower CLtot in the control rats were due to the effects of enterohepatic recycling of glycyrrhizin. Furthermore, the transport of the drug from the liver to the bile appears to be a saturable process.

Animals↗
PubMed1986

Immunohistochemical localization of urotensin I and other neuropeptides in the caudal neurosecretory system of three species of teleosts and two species of elasmobranchs.

In three species of teleosts - carp Cyprinus carpio; grass carp Ctenopharyngodon idella; and crucian carp Carassius auratus - the caudal neurosecretory system displays small, medium-sized and large neurons. Urotensin I (UI)-immunoreactive and UI-nonreactive neurons were found in all three groups; in general, the number of the latter neurons exceeded that of the former. Noteworthy are: (i) UI-immunoreactive fibers in the caudal spinal cord and (ii) dense accumulations of UI-immunoreactive product around the capillaries of the urophysis. In two species of elasmobranchs-cat shark Heterodontus japonicus and swell shark Cephaloscyllium umbratile - neurosecretory neurons decreased in size in rostro-caudal direction. Most of the neurosecretory perikarya, their axons and the corresponding neurohemal areas were UI-immunoreactive, but a small number of secretory neurons was devoid of immunoreaction. Oxytocin, arginine vasopressin, substance P, somatostatin, neurotensin, vasoactive intestinal polypeptide and gastrin-releasing peptide were not detected in the caudal neurosecretory system of the carp.

Animals↗
PubMed1986

Cloning and sequence analysis of cDNA encoding urotensin I precursor.

The primary structure of the precursor of urotensin I, a neuropeptide hormone from the caudal neurosecretory system of the carp Cyprinus carpio, has been determined by analyzing the nucleotide sequence of cloned DNA complementary to the mRNA encoding it. The precursor consists of 145 amino acid residues and the carboxyl terminus represents the 41-amino acid sequence of urotensin I, preceded by Lys-Arg and followed by Gly-Lys. Sequence homology as well as similar organization of the precursors of urotensin I and mammalian corticotropin-releasing factors suggest that they are evolutionarily related. RNA transfer blot analysis indicates that mRNA encoding the precursor of urotensin I is present only in the spinal cord and not in the brain, intestine, liver, or kidney of the carp.

Amino Acid Sequence↗