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Biomedical subjects

T Okitsu

Publications and source records attributed to T Okitsu.

At least 19 recordsLinked to original sources
PubMed1995

[Causative agent of the so-called "light disease of shrimps" is luminescent Vibrio cholerae non-O1].

A number of luminous fresh-water shrimps were found in a fish preserve in Lake Biwa, Shiga Prefecture, in the middle of July, 1994, and most of them died within several hours after collection (the so-called "light disease of shrimp"). Four luminous organisms were isolated from a dead shrimp. Although the phenotypic properties of these strains were similar to those of V. cholerae or V. mimicus, a representative strain, 838-94, was shown to have a high level (79%) of DNA homology with V. cholerae type strain, ATCC 14035 and a low level (45%) of relatedness to V. mimicus type strain, ATCC 33653. Therefore, these isolates were identified as V. cholerae. The four strains fell into serogroup O28 of V. cholerae. On the other hand, none of the isolates had CT nor NAG-ST genes. The results obtained herein clearly demonstrate that these organisms isolated from luminous shrimps are luminescent V. cholerae serogroup O28.

Animals↗
PubMed1990

Changes in tympanograms after middle ear inflation.

To determine the effects of politzerization or middle ear (ME) inflation by a catheter, we studied the ME pressures in 35 ears with retracted tympanic membranes (29 patients). Serial tympanometries were performed prior to the ME inflation and immediately, 10, 20, 30 and 60 min after the procedure. The present study showed that the more negative the ME pressure was before the inflation, the greater the pressure change was after the treatment. The elevated ME pressure induced by the procedure declined rapidly within the first 20 min after the inflation. This was probably caused mainly by spontaneous elimination of ME gas through the eustachian tube and gas absorption from the ME mucosa. During the post-inflation course, some ears demonstrated more negative pressures in the ME cavity than those before the inflation. The present investigation demonstrated that the use of inflation to treat secretory otitis media had short-term benefits which could be improved by minimizing gas absorption.

Acoustic Impedance Tests↗
PubMed1989

[The c protein fractions of group B streptococci: its distribution and relation to heat-labile antigens for the agglutination method].

Distribution of the c protein fractions of group B streptococci and relation to heat-labile antigens for agglutination were investigated. The results were summarized as follows: 1. Analysis of antigenicity of the c protein in group B streptococcal strains isolated revealed that 74% of the type Ia/c strains carried only alpha antigen, and 76% of the type Ib/c strains contained both alpha and beta antigens. Component of the c protein fractions in most of type Ia/c strains isolated was different from that in reference strains. 2. Of 37 Ia/c alpha strains, 45.9% were determined non-typable, 32.4% were Ia/W, 13.5% were Ia/S, and 8.1% were Ia/Q in the agglutination for heat-labile antigens. Of 8 Ia/c alpha beta strains, 87.5% were Ia/Q, and 12.5% were Ia/SW. Of 5 Ia/c beta strains, 60% were Ia/Q, and 40% were Ia/QW. Of 19 Ib/c alpha beta strains, 68.4% were Ib/-, and 31.6% were Ib/S. Of 5 Ib/c alpha strains, 60% were Ib/-, and 40% were Ib/S. One Ib/c beta strain was Ib/-. 3. Because trypsin-sensitive portions of the beta antigens were lost, preparation of antigens for agglutination by pancreatic digestion could not exactly reflect results of the precipitation method.

Agglutination Tests↗
PubMed1989

Labyrinthine fistulae caused by cholesteatoma. Improved bone conduction by treatment.

In five cases of labyrinthine fistulae caused by extensive cholesteatoma, more than 30-dB improvement in bone conduction was observed in four postoperative cases and in one case after preoperative administration of antibiotics. In each case, a fistula of more than 2 mm in length was present at the lateral semicircular canal, and membranous labyrinthine wall was exposed when the cholesteatoma membrane was removed. These five cases were considered to be in the stage of serous labyrinthitis. The experience with these cases shows that emergent antibiotic treatment and surgery are appropriate for cases with reduced bone conduction in which labyrinthine fistula caused by cholesteatoma is suspected. In addition, as the reduction of bone conduction does not necessarily preclude the possibility of good postoperative hearing, tympanoplasty may be appropriate even for cases with markedly reduced bone conduction due to labyrinthine fistulae.

Adolescent↗
PubMed1987

Positive intratympanic pressure in the morning and its etiology.

Intratympanic pressures were measured by tympanometer in forty ears free from disease. In the recumbent position, the first tympanogram was obtained in the morning at awakening, before swallowing. The second pressure measurement was performed in the upright position after swallowing and chewing. Twenty-two ears showed positive pressure in the middle ear before swallowing and decreased pressure after swallowing. The present results revealed no evidence of continuous gas absorption from the middle ear during sleep. The other experiment demonstrated that raising of the PCO2 level by hypoventilation increased the pressure in the middle ear. The results suggested indirectly a diffusion of carbon dioxide to the middle ear cavity from its surrounding tissue. The intratympanic pressure seems limited in part to the partial pressure gradient of gases between the middle ear cavity and its surrounding tissue when ventilation through the Eustachian tube is impaired.

Acoustic Impedance Tests↗
PubMed1987

Forward-backward tracing tympanometry.

Two tympanograms were routinely recorded from each ear by altering the pressure in the external auditory meatus (EAM), first in the decreasing direction (Forward Tracing: TG-F) and next in the increasing direction (Backward Tracing: TG-B). In a normal ear the TG-F peak tended to be in the negative pressure area and that of the TG-B in the positive area. When the middle ear pressure was adjusted to the atmospheric pressure in a model, the TG-F peak always indicated a negative pressure and that of TG-B always showed a positive pressure value. As long as the same model was used, the magnitude of the difference of the two peaks was identical irrespective of the middle ear pressure, but it was influenced by the speed of EAM pressure change, and a linear increase was observed up to the speed of 70 mmH2O/s, both in the normal ear and in the model. In ears with pathology, considerable variation was noted in the magnitude of the peak shift. These findings seem to suggest that the peak location of a unidirectionally drawn tympanogram cannot be regarded as indicating the precise middle ear pressure. The middle ear pressure can be estimated more accurately by averaging the peak pressures of TG-F and TG-B of Forward-Backward Tracing Tympanogram.

Acoustic Impedance Tests↗
PubMed1986

Tympanograms in ears with small perforations of the tympanic membranes.

It has been believed that in an ear with a perforation, the tympanogram becomes a straight line due to the lack of compliance change in response to the pressure change in the external auditory meatus. Recently, however, we found two types of tympanogram with distinctive characteristics in ears with small perforations. In the first tympanogram type, when the external auditory meatus pressure was changed in the decreasing direction, the compliance peak was formed in the positive-pressure area, whereas it was formed in the negative-pressure area when it was changed in the increasing direction. The difference of the pressure at which compliance peak was obtained was great. The second tympanogram type was unique, with multiple notches similar to those of electronystagmographic recordings of the jerky nystagmus. Knowledge of these tympanograms helps in recognizing small tympanic-membrane perforations.

Acoustic Impedance Tests↗
PubMed1985

Forward-backward tracing tympanometry in the diagnosis of middle ear pressure.

Two tympanograms (TG) were routinely recorded on each ear by changing the pressure in the external auditory meatus (EAM), one in the decreasing (forward tracing: TG-F) followed by the other in the increasing direction (backward tracing: TG-B). Both TG were drawn on the same chart and the peak locations were compared. In a normal ear the TG-F peak tended to be formed in the negative pressure area and that of TG-B in the positive area. In a model whose middle ear pressure (MEP) was adjusted to the atmospheric pressure, the TG-F peak always indicated a negative pressure and that of TG-B a positive pressure value. As long as the same model was used, the magnitude of peak shift was identical irrespective of the middle ear pressure. The magnitude of the peak shift was influenced by the speed of EAM pressure change and a linear increase was observed up to the speed of 70 mmH2O/sec, both in a normal ear and a model. These findings seem to suggest that the peak location of a unidirectionally drawn TG can not be regarded as indicating the precise MEP. A valid MEP can better be estimated by averaging the peak pressure of TG-F and TG-B of forward-backward tracing tympanogram. In ears with pathology considerable variation was noted in the magnitude of the peak shift, so that relying solely on unidirectionally drawn TG could have lead to misdiagnosis in some cases. This was especially true with ears having small perforations covered with granulation or fluid.

Acoustic Impedance Tests↗
PubMed1985

Tympanograms of otitis media with effusion: an experimental study.

A sufficient explanation concerning tympanogram (TG) of otitis media with effusion (OME) has not been reported. The purpose of the present study was to investigate the relationship between the types of TG and actual pathological status of the middle ear system by means of experimentally modified middle ear clefts. In the present experiments, human temporal bones, guinea pigs' bullae and plastic models were used. The results were as follows: (1) Water was gradually poured into the middle ear cleft through the Eustachian tube. When the water level rose above the umbo, the height of TG slightly exceeded that of the original TG. Further addition of water produced M-shaped TG, however, flat TG (type B) was not detected until the water-line nearly reached the aditus. A similar phenomenon was observed in the plastic models when the water level reached the aditus-equivalent-site. (2) Tympanometrically measured middle ear pressure (MEP) was almost equivalent to the actual MEP recorded by a manometer when the tympanic membrane was normal. However, this result could not be duplicated in flaccid or adhesive tympanic membrane cases. (3) A clear reduction in the height of TG in guinea pigs' bullae was observed with decreased air volume. In addition, shallow TG was produced by an occlusion of the aditus of the human temporal bones and of the aditus-equivalent-site of the plastic models. It was demonstrated that the TG pattern depends on the fluid volume and location, air volume of mastoid cavity, intratympanic pressure and eardrum condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Impedance Tests↗