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Biomedical subjects

A Maeda

Publications and source records attributed to A Maeda.

At least 379 records · Page 21Linked to original sources
PubMed1980

Formation of 9-cis- and 11-cis-retinal pigments from bacteriorhodopsin by irradiating purple membrane in acid.

Both light-adapted and dark-adapted forms of bacteriorhodopsin in purple membrane in 67% glycerol solution were allowed to stand in acidic conditions by the addition of HCl to final concentrations from 4 X 10(-4) to 2 X 10(-2) M for 24 h at 3 degrees C. Over this concentration range, the acid-induced products from both species showed a maximum absorbance around 600 nm and high-performance liquid chromatography of extracted retinal isomers revealed that the acid-induced form of bacteriorhodopsin has 13-cis- and all-trans-retinals in a molar ratio of 4:6, which is intermediate between those of the dark-adapted and the light-adapted forms at neutral pH values. Exposure of the acid-induced form of bacteriorhodopsin to light at wavelengths longer than 670 nm at 3 degrees C caused a decrease of the absorbance around 600 nm with a concomitant rise of the absorbance around 500 nm. The extract from the irradiated products of bacteriorhodopsin in acid contained 9-cis- and 11-cis-retinals in addition to 13-cis- and all-trans-retinals. The absorbance maximum estimated from the analysis of the absorption spectra and the composition of the isomers was found at 495 nm for the 9-cis-retinal pigment and around 560 nm for the 11-cis-retinal pigment. On irradiation with 438-nm light, the 9-cis-retinal pigment disappeared with a concomitant increase of both the 13-cis- and all-trans-retinal pigments as judged by chromophore analysis and the absorption spectrum. The 9-cis-retinal pigment brought to pH 9 exhibited a maximum absorbance at 450 nm; this could be decomposed by the action of hydroxylamine or converted to a form resembling normal bacteriorhidopsin by 438-nm irradiation.

Bacteriorhodopsins↗
PubMed1980

Adenovirus type 10 keratoconjunctivitis with increased intraocular pressure.

An 18-year-old man, with serologically diagnosed adenovirus type 10 infection, had keratoconjunctivouveitis of both eyes after pharyngitis with transient increased intraocular pressure. Increased intraocular pressure, ranging from 46 to 28 mm Hg during medical therapy, lasted for about ten days in the early stage of the disease. Many punctate corneal opacities developed bilaterally two weeks later and disappeared within ten months. Analysis of the clinical findings demonstrated that the increased intraocular pressure may have been secondary glaucoma due to keratoconjunctivitis caused by adenovirus infection.

Adenoviridae Infections↗
PubMed1980

Calicivirus detected in outbreaks of acute gastroenteritis in school children.

Outbreaks of acute gastroenteritis occurred in AK and N Primary Schools of Osaka Prefecture early in March and early in November, respectively, 1977. Epidemiological surveys were carried out in both schools with the following results. The morbidity rates were 21.8% (AK) and 8.5% (N) among all pupils, and 41.7% (AK) and 36.8% (N) in special age groups. The main clinical symptoms were abdominal pain (77.2-91.3%), diarrhea (38.4-41.3%) and vomiting (6.5-41.6%). Electron microscopic observations of negatively stained specimens showed that five of 15 fecal extracts obtained from patients in the two schools contained virus particles of 35-40 nm diameter with some black hollows on the surface of complete particles and ten projection-like structures at the edge of empty shells. These morphological characteristics resemble those of calicivirus particles. Immune electron microscopic examination suggested that outbreak in AK School was associated with this virus. Attempts to cultivate the viruses in various cultured cells and in suckling mice were unsuccessful.

Antibodies, Viral↗
PubMed1979

Fluorescein mercuric acetate as a probe of the dynamic structure of double-helical DNA.

Fluorescein mercuric acetate causes the unwinding of DNA and binds to the separated bases. The kinetics of this unwinding process were studied using both untreated DNA and sonicated DNA at various pH values (6.8--9.3) and Na+ concentrations (10--250 mM). The unwinding process is explained by assuming a nucleation in the middle of DNA (as a function of time) as well as at the helix ends (immediately after addition of this reagent) and the subsequent growth of the nuclei. The frequency of the nucleation in the middle of DNA appears to be markedly affected by pH and Na+ concentration. In contrast, the reaction rate of this reagent with heat-denatured DNA was almost insensitive to these environmental variables. The growth rate of the unwinding nuclei in double-stranded DNA also appears insensitive. The most important implication of this study is that in the low pH range (6.8--7.5) the reactivity of thermally-induced locally open regions in the middle of double-helical DNA toward this reagent appears much higher than that of heat-denatured DNA. Since this reagent is negatively charged, these findings are discussed in view of its electrostatic interaction with the locally open regions.

Chemical Phenomena↗
PubMed1979

Formation of 7-cis- and 13-cis-retinal pigments by irradiating squid rhodopsin.

Squid rhodopsin was irradiated with orange light (greater than 530 nm) at various temperatures from -190 to 10 degrees C until a photo-steady-state mixture was formed. Then the chromophoric retinals were extracted from the photo-steady-state mixtures and their isomer composition was analyzed by high-performance liquid chromatography. In the case of photo-steady-state mixture formed at -85 degrees C, large peaks in the chromatogram were found at the positions of both 7-cis- and 13-cis-retinals. Each peak was further identified by synthesizing the pigments from these retinals with cattle opsin or apobacteriorhodopsin. Both 7-cis- and 13-cis-retinals were also extracted from a photo-steady-state mixture formed by irradiation at -40, at 0, or at 10 degrees C. These isomers were scarcely detected in a photo-steady-state mixture formed by irradiation at -190 degrees C, though 9-cis-retinal was found as a major constituent in this mixture. Irradiation of lumirhodopsin at -190 degrees C, however, produced 7-cis-retinal pigment. These findings suggest that bathorhodopsin may have a conformation to prevent the formation of 7-cis-retinal from the all-trans form and that this particular conformation may be relaxed by the conversion of bathorhodopsin to lumirhodopsin.

Animals↗
PubMed1979

Effects of enflurane anaesthesia and surgery on endocrine function in man.

Forty-five patients underwent enflurane anaesthesia and surgery. Anaesthesia alone evoked little change in the plasma concentrations of ACTH, cortisol or antidiuretic hormone (ADH), but there were significant increases during surgery. The plasma concentrations of aldosterone increased during anaesthesia alone, and a further increase was noted during surgery. Neither enflurane anaesthesia nor surgery significantly influenced plasma concentrations of renin activity and thyroxine. A significant decrease in the plasma triiodothyronine concentrations was detected during anaesthesia alone, and a further decrease was found during and following surgery. Enflurane anaesthesia did not affect the plasma concentration of luteinizing hormone (LH) in male subjects throughout surgery, but a significant decrease in female patients was detected to the first day after operation. The plasma concentrations of testosterone decreased during anaesthesia alone and surgery, and a further decrease was noted on the first day after operation.

Adolescent↗
PubMed1979

Effects of enflurane anaesthesia and surgery on endocrine function in man.

Forty-five patients underwent enflurane anaesthesia and surgery. Anaesthesia alone evoked little change in the plasma concentrations of ACTH, cortisol or antidiuretic hormone (ADH), but there were significant increases during surgery. The plasma levels of aldosterone rose during anaesthesia alone, and a further increase was noted during surgery. Neither enflurane anaesthesia nor surgery significantly influenced plasma concentrations of renin activity and thyroxine. A significant decrease in the plasma triiodothyronine levels was detected during anaesthesia alone, and a further decrease was found during and following surgery. Enflurane anaesthesia did not affect the plasma level of luteinizing hormone (LH) in male subjects throughout surgery, but a significant decrease was detected in female patients on the first postoperative day. The plasma concentrations of testosterone decreased during anaesthesia alone and surgery, and a further decrease was noted on the first postoperative day.

Adolescent↗
PubMed1979

Epidemiological and virological studies on outbreaks of acute gastroenteritis associated with rotavirus in primary schools in Osaka.

There have been three recent outbreaks of acute gastroenteritis in primary schools in Osaka prefecture caused by rotavirus: one in a school (TA) in April, 1974 and two in two other schools (TE and K) in May 1975. The morbidity from the disease was 2.4--15.8% for all age groups in the schools, and 20.1--34.1% for a certain age group. The disease lasted for 4 (K) to 14 days (TE). The first cases in schools TA and TE were followed by successive cases. The main clinical symptoms were higher frequencies of diarrhea (68--71.4%) and fever (78%) than in winter vomiting disease. There was no difference in the incidences of the disease in boys and girls. From observation on the disease in individual families, the incubation period seemed to be 3 days. Using paired sera and Neonatal Calf Diarrhea Virus (NCDV) as antigen, positive seroconversion was demonstrated by the complement fixation test and marked seroconversion by the indirect fluorescent antibody technique. With these techniques, specific antibody to NCDV was detectable in the sera from an early stage of illness. Rotavirus was found on electron microscopic examination of some fecal specimens of patients in TA, but not in those of patients in TE or K, although adenovirus was isolated from one patient. A serological survey of healthy children aged 0 to 12 showed that rotavirus is a common virus in Osaka.

Acute Disease↗