Influence of postmenopausal state, solar radiation, drugs and comorbidities on serum calcium and phosphate in 13,000 hospital admissions.

AIMS: Our goal was to determine the relative contributions of demographic variables, drugs, comorbidities, and weather conditions on serum calcium (Ca) and phosphate (Pi) in patients admitted to a tertiary referral center. METHODS: For 12,667 consecutive patients admitted to the Kantonsspital St. Gallen, drug history on admission, age, sex, body weight, ICD-10 diagnoses, and laboratory data were extracted from electronic medical records. Weather parameters prior to hospital admission were also integrated in a regression analysis. RESULTS: Serum Ca was normally distributed with a median (interquartile range) of 2.3 (2.2/2.4) mmol/L. In contrast Pi showed a right tailed distribution of 1.0 (0.9/1.2) mmol/L. Ca was increased in postmenopausal women. Solar radiation prior to admission was associated both with higher Ca and higher Pi. Lower blood pressure was associated with lower Ca and higher Pi. In addition Ca increased by 0.017 mmol/L per g/L increase of albumin (p < 0.0001). CONCLUSIONS: Serum Ca and Pi at hospital admission are highly dependent on patient characteristics, drugs, and comorbidities. In particular, we found higher Ca in postmenopausal women. The commonly applied albumin correction formula of Payne (0.025 mmol/L Ca per g/L albumin) may overestimate the effect of albumin; we propose using 0.017 mmol/L Ca per g/L albumin or measurement of free (ionized) Ca.

Sound level dependence of the primary auditory cortex: Simultaneous measurement with 61-channel EEG and fMRI.

Sound level dependence has been investigated for years with event-related potentials (ERP). A serotonergic modulation of the sound level dependence only of the primary auditory cortex but not of the auditory association cortex has been suggested by a number of clinical and preclinical studies. Therefore, a precise covering of the activity of the primary auditory cortex seems necessary if sound level dependence is used as an indicator of the central serotonergic system. Recent fMRI studies described a pronounced sound level dependence only in the Heschl gyrus/primary auditory cortex but not in auditory association areas. In the present simultaneous 61-channel EEG and fMRI study investigating fourteen healthy subjects, we found a high correlation between the loudness-dependent change of the extent of fMRI activation (number of activated voxels) and the corresponding changes of the mean current source density within the same region of interest covering the primary auditory cortex (r = 0.84, P < 0.001). Our findings suggest a close relationship between the fMRI signal and event-related potential activity. In addition, the correspondence of the ERP-based data and the fMRI results further supports the validity of the ERP localization approach.