Breathing frequency (f) is often reported as having an integer-multiple relationship to limb movement (entrainment) during rhythmic exercise. To investigate the strength of this coupling while running under hypoxic conditions, two male Caucasians and four male Nepalese porters were tested in the Annapurna region of the Himalayas at altitudes of 915, 2,135, 3,200, 4,420, and 5,030 m. In an additional study in a laboratory at sea level, three male and four female subjects inspired various O2-N2 mixtures [fraction of inspired O2 (FIO2) = 20.93, 17.39, 14.40, 11.81%] that were administered in a single-blind randomized fashion during a treadmill run (40% FIO2 maximum O2 consumption). Breathing and gait signals were stored on FM tape and later processed on a PDP 11/73 computer. The subharmonic relationships between these signals were determined from Fourier analysis (power spectrum), and the coincidence of coupling occurrence was statistically modeled. Entrainment decreased linearly during increasing hypoxia (P less than 0.01). Moreover, a significant linear increase in f occurred during hypoxia (P less than 0.05), whereas stride frequency and metabolic rate remained constant, suggesting that hypoxic-induced increases in f decreased the degree of entrainment.

Following a 4-week history of coughing, a 12-year-old cat with a history of insulin-dependent diabetes mellitus was diagnosed with a pulmonary granuloma caused by Cladophialophora bantiana. Thoracic radiographs revealed consolidation of the right caudal lung lobe and cytology confirmed the presence of mycotic pneumonia. Results of clinical investigations showed no evidence of extra-pulmonary infection. A thoracotomy and lung lobe resection was performed. Histological examination of the mass revealed black pigmented fungal hyphae and pyogranulomatous inflammation. Cultures inoculated with portions of these tissues yielded a dark walled fungus consistent with an etiologic agent of phaeohyphomycosis and DNA sequencing confirmed the presence of Cladophialophora bantiana. The cat was treated with itraconazole for 4 weeks post-operatively and then with posaconazole for 7 months but was euthanized 13 months after initial diagnosis due to a hepatocellular carcinoma. On post-mortem examination there was no evidence of recurrent fungal infection. This is the first report of localized pulmonary C. bantiana infection in a cat.

Case summaryAn 18-month-old, female spayed, Australian Mist cat presented with a 24 h history of muscle tremors and inappetence progressing to collapse with generalised muscle fasciculations. The cat was diagnosed with a hypochloraemic metabolic alkalosis due to a duodenal foreign body found to be a trichobezoar at coeliotomy. The cat made a complete recovery after enterotomy to remove the trichobezoar, with cessation of neuromuscular clinical signs and normalisation of its electrolyte and acid–base imbalances.Relevance and novel informationMuscle fasciculations and tremors in cats can be caused by intoxications, metabolic derangements, encephalomyelitis, feline hyperaesthesia syndrome and cerebellar diseases. The presenting clinical signs of severe muscle fasciculations and tremors have not previously been reported in association with an intestinal obstruction in the cat.

Streamlining of air flow in the upper airways and trachea has been investigated by inhaling 8lmkrypton through each side of the nose separately and counting over the lung fields with a gamma camera. 8lmKr inhaled through one nostril was uniformly mixed in the air stream by the time the carina was reached. Gas mixing occurs probably by a combination of diffusion and turbulent flow.