A series of experiments was undertaken to investigate the infection dynamics of various doses of S. typhimurium in day-old and 14-day-old broiler chickens kept in isolators. The infections were followed quantitatively in ceca and ileum by enumerating the colony forming units (cfu) of the challenge strain. It was found that the inoculation of 10(7) cfu of S. typhimurium to day-old chickens established stable cecal infection in all the animals for 35 days. For 14-day-old chickens, stable and lasting infections were seen with inoculation of 10(9) cfu. Lower doses yielded more variable results, and the bacteria were rapidly eliminated from most birds, especially in 14-day-old inoculated chickens. Salmonella was found in spleen and liver 2-3 days postinoculation. Salmonella was cleared from both organs or reduced to very low numbers within 3 weeks.

Aging↗

PubMedDate not supplied

Immediate restoration of basal sensorineural hearing (Mb Meniere) using a pressure chamber.

A new technique for the restoration of basal sensorineural hearing loss in Mb Meniere was described. Three cases with unilateral basal sensorineural hearing loss, fullness of the ear, and tinnitus were reported. In the acute stage of their disease the patients were treated in a pressure chamber where it was possible to increase or decrease the air pressure within the range +/- 110 cm H2O. The equilibration of middle ear pressures to surrounding air pressures was checked. Exposure to underpressure resulted in a rise of the hearing thresholds at low frequencies and relief of subjective symptoms. When the air pressure was increased the hearing thresholds were lowered and the sensation of tinnitus and fullness of the ear was accentuated. Changes in air pressure did not affect the healthy ears or the high frequencies in the diseased ear. Hearing improvement attained at exposure to underpressure seemed to remain at atmospheric pressure level. The investigation was performed on the hypothesis that a distended membranous labyrinth might cause a venous congestion of the vestibular aqueduct, resulting in impaired endolymph absorption in the endolymphatic sac. Possible effects of changes in environmental air pressure on the inner ear were discussed.

Adult↗

PubMedDate not supplied

Volume-pressure properties of round and oval windows. A quantitative study on human temporal bone.

A model study was carried out on human temporal bones to assess quantitatively the displacement of the round and oval windows when different pressure levels were applied to the external ear canal and inside the middle ear. It was found that the major displacements of the window membranes occurred in the pressure range of +/- 20 cm H2O in the intact middle ear. An additional increase in the middle ear pressure up to +/- 70 cm H2O caused a minor displacement of the window membranes.

Aged↗

PubMedDate not supplied

The influence of perilymphatic pressure on the displacement of the tympanic membrane. A quantitative study on human temporal bones.

A model study on human temporal bones was performed. A microflow method was used in order to assess the possibility of making indirect recordings of changes in the inner ear pressures. Changes in the perilymphatic pressure were recorded as displacements of the tympanic membrane, the stapedius reflex being artificially elicited by forces applied briefly to the stapedius tendon. Changes in the perilymphatic pressures in the range of +/-15 cm H2O affected the position of the tympanic membrane and the "stapedius reflex response". The microflow method used seems suitable for the clinical recording of changes in the intralabyrinthine pressure.

Adult↗