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Biomedical subjects

M Sakai

Publications and source records attributed to M Sakai.

At least 919 records · Page 51Linked to original sources

Interrelationship between splenic and superior mesenteric venous circulation manifested by transient splenic arterial occlusion using a balloon catheter.

We examined the hemodynamic changes induced by transient splenic arterial occlusion using a balloon catheter to investigate the hemodynamic effect of transcatheter splenic arterial embolization--a procedure that has been used since its introduction in 1973 as therapy for hypersplenism and more recently for portal hypertension. The blood flow volume was measured in 20 patients with liver disease using an ultrasonic duplex system (Toshiba SAL50A/SDL-01A). The portal venous pressure was also measured via a 3F catheter using a transducer. The catheter was placed in position by substituting it for a 25-gauge needle that had been inserted into the portal vein under ultrasonic guidance percutaneously and transhepatically. Splenic arterial occlusion caused a drop in splenic venous blood flow from 708 +/- 487 to 241 +/- 155 ml per min, in portal venous blood flow from 993 +/- 439 to 807 +/- 419 ml per min and in portal venous pressure from 17.4 +/- 7.2 to 14.4 +/- 6.1 mm Hg. The latter two reductions were less than expected from the decrease in the splenic venous blood flow volume. This phenomenon was caused by an increase in the mesenteric venous blood flow from 475 +/- 126 to 630 +/- 270 mm per min. This increase may be due to a compensatory mechanism under the control of a regulatory loop in the liver or portal vein, and there seems to be a relationship between splenic and intestinal circulation in portal hypertension that maintains hepatic circulation.

Embolization, Therapeutic↗

Location of the reproductive timer in the male cricket Gryllus bimaculatus DeGeer as revealed by local cooling of the central nervous system.

The location of the reproductive timer for the post-copulatory, time-fixed, sexually refractory stage was investigated in the male cricket Gryllus bimaculatus. This stage was defined as the interval between spermatophore protrusion and recommencement of copulation or a calling song. To inactivate the central nervous system locally and reversibly, different body regions were cooled to 10 degrees C for 20-30 min after spermatophore protrusion. A behavioural test then measured the duration of the refractory stage after males recovered from cooling. Males with the head, thorax and anterior abdomen cooled did not show a lengthening of that stage. In contrast, males with the entire abdomen or even the posterior abdominal segments containing only the 6th and terminal (7th-11th) abdominal ganglia showed a lengthening of the refractory stage up to, but not exceeding, the cooling duration. When 20-min cooling was interposed twice after spermatophore protrusion, the refractory stage was lengthened by about 40 min, indicating that interposed cooling did not reset the timer. These results are in agreement with our previous hypothesis that the reproductive timer for the refractory stage in the male cricket is located in the posterior abdominal ganglia, possibly within the terminal abdominal ganglion.

Abdomen↗

Isolation of major histocompatibility complex class I cDNA from pink salmon (Oncorhynchus gorbuscha).

An MHC class I cDNA clone was isolated from pink salmon (Oncorhynchus gorbuscha). Eight amino acids, which have been shown in mammals to bind main-chain atoms of peptides, are well conserved in the salmon alpha 1 and alpha 2 domains. Nine amino acids in the alpha 3 domain are classified by Williams and Barclay (Ref. 1. Ann. Rev. Immunol. 6:381-405, 1988) as signature immunoglobulin superfamily residues. The pink salmon MHC class I extracellular domains show 84.2% amino acid identity with those of Atlantic salmon (Sasa p30). polymorphism of the MHC class I alpha 1 domain was determined using PCR with genomic DNA from 12 fish. Sixteen variants were identified with most diversity concentrated in those amino acids that bind directly to peptides in mammalian class I molecules. Non-synonymous substitutions predominate over synonymous ones in the codons encoding these polymorphic residues.

Amino Acid Sequence↗

Mutagenicity of polycyclic aromatic hydrocarbons and quinones on Salmonella typhimurium TA97.

18 polycyclic aromatic hydrocarbons (PAHs) and 7 quinones were tested for mutagenicity using Salmonella typhimurium TA97, TA98 and TA100 with or without metabolic activation. In the presence of metabolic activation, TA97 was more susceptible to mutation than either TA98 or TA100 by many of PAHs tested. PAHs such as 1-methylphenanthrene, fluoranthene, pyrene, benzo[a]pyrene, benzo[e]pyrene and perylene had high mutagenic effects on TA97 in the presence of metabolic activation. 1,6- and 1,8-pyrenequinones were also highly mutagenic on TA97 in the presence or absence of metabolic activation. It appears that pyrene is mutagenic through its metabolic conversion to pyrenequinones.

Animals↗

Interpretations of the "balanced meal" household food security indicator.

The study objective was to quantify interpretations of the term "balanced meals" used in food security status assessments. Telephone interviews included 77 charitable food recipients in Hawaiì. After participants first responded to the question of whether they could afford to eat balanced meals, they next defined what a "balanced meal" meant. Qualitative responses were categorized into common themes. Forty-one (53%) indicated that a balanced meal consisted of at least three food groups.Thirty-one (40%) indicated something other than three food groups; five (6%) had no idea what a "balanced meal" meant. The findings question the validity and reliability of responses to "balanced meal" food security indicators in Hawaiì.

Adult↗

Isolation, structure, and synthesis of novel 4-quinolinone alkaloids from Esenbeckia leiocarpa.

Two new biocidal quinolinone alkaloids, 3-methoxy-1-methyl-2-propyl-4-quinolone [1] and 2(1'-ethylpropyl)-1-methyl-4-quinolone [2], were efficiently isolated using reversed-phase recycling hplc from the leaves of Esenbeckia leiocarpa. The structures were determined through spectroscopic data and confirmed by total synthesis. These alkaloids have antifeedant activities against the pink bollworm, Pectinophora gossypiella.

Alkaloids↗

Can short-latency vestibulospinal reflexes in lower leg muscles be elicited by tapping the head?

A gentle tap on the forehead evoked short-latency motor responses in the sternocleidomastoid muscle, which may be vestibulocollic reflexes with characteristics similar to those elicited by clicks. We tested this paradigm in subjects standing upright, in order to determine the differential effects of taps on the forehead on the patterns and latencies of spinal stretch and vestibulospinal reflexes, which are important for postural control. Taps on the forehead elicited short-latency inhibitory electromyographic responses in both gastrocnemius muscles with a mean latency of 48.3 +/- 3.1 ms (onset) to 98.3 +/- 6.3 ms (end). Taps on the sternum elicited similar responses from the gastrocnemius muscles, indicating that vestibular stimulation is not essential for eliciting these responses. Both responses may play a role in predetermining the strategy for correcting body perturbations. The actual reflex is probably elicited by somatosensory input from the neck, which converges with vestibular input for the multisensory control of posture.

Acceleration↗

Analysis of epitopes of mouse monoclonal antibodies against human alpha-fetoprotein.

Thirty-six monoclonal antibodies (MAbs) against human alpha-fetoprotein (AFP) were analyzed for the location of their epitopes by reacting them with a set of yeast recombinant AFP proteins using ELISA. Recombinant AFP proteins containing either one, two or all three domains, i.e. domain I, domain III, domain I-II, domain II-III and domain I-II-III, were produced and secreted into the culture medium of yeast cells harboring the expression plasmids. Epitopes of 13 MAbs were localized on domain I and 17 others were on domain III. However, the exact location of the epitopes of the remaining 6 MAbs could not be defined. The epitope of an antibody, namely AFY6, which was located in domain I, was successfully mapped on an octapeptide, C175KAENAVE182, using synthesized overlapping octapeptides.

Animals↗

Comparison of horizontal nystagmus in different head positions: a study by damped pendular rotation test.

Damped pendular rotation was given with the initial maximum speed of 180 degrees/s. The subject's head was tilted forward at an angle of 30 degrees from the upright position, or kept in the upright position, or tilted backward at 30 degrees from the upright position. Electronystagmography was used to evaluate the maximal slow-phase eye velocity (mx SPEV) of the horizontal nystagmus. Differences existed in mx SPEVs of the horizontal nystagmus for the head-tilted positions at 30 degrees forward or backward and that obtained in the upright position. The mx SPEV of the horizontal nystagmus in the upright position was higher than those acquired in the head-tilted positions.

Adult↗

Evaluation of the vertical semicircular canal function by the pendular rotation test: a study on patients with benign paroxysmal positional vertigo.

The pendular rotation test (non-damped) in a head-tilted position, 60 degrees backward and then rotated 45 degrees either to the right or left, was performed in 6 patients with benign paroxysmal positional vertigo. The stimulus mode was amplitude = 360 degrees, frequency = 0.1 Hz, and the maximal speed = 114 degrees/s. By this test procedure, it was possible to evaluate the excitability of vertical semicircular canals. Using an infra-red CCD camera and a personal computer system, the evoked nystagmus was analysed. A statistically significant difference (p < 0.05) in the maximal slow-phase eye velocity of vertical nystagmus was found between those from the anterior semicircular canal and those from the posterior semicircular canal. The excitability of the posterior semicircular canal in the affected ear was found to be lower than that of the anterior semicircular canal.

Adult↗

Klippel-Feil syndrome with conductive deafness and histological findings of removed stapes.

The Klippel-Feil syndrome is usually associated with sensorineural hearing impairment, but rarely is it associated with conductive or mixed deafness. A 22-year-old female presented with fusion of the cervical vertebrae, torticollis, scoliosis, pterygium colli, the Sprengel deformity with an omovertebral bone, concavity of the thorax and conductive hearing impairment of the right ear. Tympanotomy disclosed an atrophic long process of incus and a fixation of the stapes footplate, and stapedectomy was performed with immediate postoperative improvement of hearing. However, she developed a sudden hearing loss with dizziness soon after she had physical exercise on the 15th postoperative day, and revision surgery revealed a perilymph fistula of the oval window. Histological investigations of the removed stapes showed no specific osseous changes but hyperostosis of the posterior edge of the footplate. The literature is reviewed and the etiology of the conductive deafness and the perilymph fistula is discussed.

Adult↗

Acceleration of fructose mediated collagen glycation.

The effect of fructose on the formation of advanced Maillard reaction products which show fluorescence and have crosslinking was investigated. Type I collagen was added to various concentrations of glucose and fructose which were then incubated at 37 degrees C for 4 weeks. The level of furosine and the fluorescence intensity both increased in direct proportion to glucose and fructose levels and to the duration of incubation. Incubation with fructose produced less furosine but more intense fluorescence than incubation with glucose. Furthermore, collagen was significantly less soluble after incubation with fructose than after incubation with glucose. These results suggest that fructose in the polyol pathway plays an important role in the formation of advanced Maillard products.

Collagen↗

Influence of serum protein levels on serum fructosamine levels.

The serum fructosamine level is influenced by the serum protein level. Therefore, we investigated the relationship between serum fructosamine levels and serum total protein and albumin levels measured simultaneously in non-diabetic and diabetic patients. Significant positive correlations were found between them. A correction formula was constructed to express the serum fructosamine level when the serum total protein level was 7 g/dl or when the serum albumin level was 4 g/dl: corrected fructosamine (mmol/l) = measured fructosamine (mmol/l) + A (7 (g/dl) or 4 (g/dl)--serum total protein (g/dl) or serum albumin (g/dl] where A is 0.28 for serum total protein and 0.30 for serum albumin in non-diabetic subjects; 0.29 for serum total protein and 0.31 for serum albumin in non-diabetic and diabetic subjects combined.

Blood Glucose↗