Circulating Basophils as a Prognostic Marker for Response to Bacillus Calmette-Guérin

PURPOSE

To predict recurrence and progression in non-muscle-invasive bladder cancer (NMIBC) patients receiving bacillus Calmette-Guérin (BCG), we evaluated circulating basophils as a biomarker that could be detected from the complete blood count.

PATIENTS AND METHODS

We use a pooled cohort of patients from the Centre Hospitalier Universitaire de Québec-Université Laval (2016-2020) and the Vancouver General Hospital (2010-2018) where a complete blood count was available before transurethral resection of bladder tumor (TURBT) of a high-grade NMIBC and subsequent BCG. Descriptive statistics described the cohort based on the dichotomous presence or absence of basophils on the complete blood count. Kaplan-Meier estimates and a log-rank test compared recurrence-free survival (RFS) and progression-free survival (PFS), with multivariable cox regression analysis used to estimate proportional hazard ratios.

RESULTS

The study cohort included 261 patients, with a median follow-up of 31.5 months (interquartile range 18.1-45.0 months). The median age was 74.0 years and 16.8% were female. Circulating basophils were detectable in 49 (18.9%) patients. Both RFS and PFS were significantly lower in patients with detectable basophils. Multivariable analysis demonstrated detectable basophils were an independent predictor of both recurrence (HR = 1.85; 95% confidence interval [CI] 1.20-2.85; P = .01) and progression (HR = 2.29; 95% CI 1.14-4.60; P = .02).

CONCLUSION

Our results confirm that baseline levels of circulating basophils are an immunological biomarker to predict recurrence and progression of NMIBC.

Intermittent hypoxia and plasticity of respiratory chemoreflexes in metamorphic bullfrog tadpoles

We tested the hypothesis that intermittent hypoxia elicits plasticity in respiratory chemoreflexes in bullfrog tadpoles. Metamorphic tadpoles (Taylor-Kollros stages XVI-XX) were subjected to intermittent hypoxia (PW(O(2))=45 Torr; 12 h/day) or constant normoxia (PW(O(2))=156 Torr) for 2 weeks before ventilatory responses to hypoxia and hypercarbia were measured. Buccal pressure changes were used to quantify the frequency and amplitude of movements associated with gill and lung ventilation. Morphometric assessment showed that intermittent hypoxia delayed development in comparison with controls. Oxygen consumption was enhanced in tadpoles subjected to intermittent hypoxia; however, this increase was not sufficient to affect basal ventilatory activity or the hypoxic ventilatory response. During acute hypercarbic exposure, tadpoles subjected to intermittent hypoxia showed (1) a greater decrease in gill ventilation frequency and (2) a greater increase in lung ventilation frequency than tadpoles maintained under control conditions. We conclude that intermittent hypoxia augments the responsiveness to hypercarbia, thereby promoting lung ventilation when animals face this stimulus. This manifestation of respiratory plasticity may reflect uncoupling between physiological and morphological development in the bi-modally breathing bullfrog tadpole.

Immunocytochemical localization of seleno-glutathione peroxidase in the adult mouse brain

Cytoplasmic seleno-glutathione peroxidase, by reducing hydrogen peroxide and fatty acid hydroperoxides, may be a major protective enzyme against oxidative damage in the brain. Oxidative damage is strongly suspected to contribute to normal aging and neurodegenerative process of Alzheimer's and Parkinson's diseases. We report here an immunocytochemical analysis of the localization of glutathione peroxidase in the adult mouse brain, carried out with an affinity-purified polyclonal antibody. Most of the brain areas analysed showed weak to strong glutathione peroxidase immunoreactivity, expressed in both neurons and glial cells. The strongest immunoreactivity was found in the reticular thalamic and red nuclei. Highly immunoreactive neurons were observed in the cerebral cortex (layer II), the CA1, dentate gyrus and pontine nucleus. Other regions, such as the caudate-putamen, septum nuclei, diagonal band of Broca, hippocampus, thalamus and hypothalamus, showed moderate staining. This study provides original information about the wide distribution of glutathione peroxidase in the mouse brain. Double-staining experiments indicated that specific subsets of cholinergic neurons in septal and diagonal band nuclei were negative for this antigen. Similarly, many dopaminergic neurons of the substantia nigra pars compacta expressed low levels of glutathione peroxidase antigen, in contrast to the ventral tegmental area, wherein most catecholaminergic cells were strongly positive. A lack of glutathione peroxidase in subsets of dopaminergic or cholinergic neurons may thus confer a relative sensitivity of these cells to oxidative injury of various origins, including catecholamine oxidation, neurotoxins and excitotoxicity.