F-18-fluoride-PET for dynamic in vivo monitoring of bone formation in multiple myeloma

Background: Bone disease in multiple myeloma is characterized by reduced bone formation. The gold standard of bone formation is the mineral apposition rate (MAR), an invasive technique reflecting bone formation at a single site. We compared F-18-fluoride-PET with the MAR in myeloma patients. Methods: Bone formation was measured before and after bortezomib treatment by determination of the MAR in iliac bone marrow biopsies and the measurement of F-18-uptake. Results: The inter-and intra-individual variations in F-18-uptake (SUVA50%) were pronounced as 33.50 (range 4.42 to 37.92) and 27.18 (range 4.00 to 31.18), respectively. A significant correlation between the MAR and F-18-uptake was found (r = 0.80, p = 0.017). There was a heterogeneous response after treatment varying from -2.20 to 4.53. Conclusions: Iliac F-18-uptake was associated with the local MAR in myeloma patients. Furthermore, F-18-fluoride-PET demonstrated the heterogeneity of in vivo bone formation, enabling monitoring during treatment

Obsessive-compulsive symptoms in psychotic disorders: longitudinal associations of symptom clusters on between- and within-subject levels

Obsessive-compulsive symptoms (OCS) are frequently reported in patients with schizophrenia and have been associated with subjective distress and higher impairment. Recent studies suggest fluctuation in co-occurring OCS and associations with the course of psychotic symptoms. Current evidence is limited by few studies with long assessments intervals and a sole focus on between-subject comparisons. The aim of this study was to specifically investigate co-variation of symptom domains over time within individuals. Patients with a psychotic disorder (n = 56) and un-affected siblings (n = 49) completed monthly assessments of clinical and subclinical symptoms over 6 months. Mixed-model multilevel analyses examined the variability and relationship between OCS and positive, negative, and depressive symptoms on the between- and within-subject level. Symptom domains were associated across subjects and assessment times, in patients and siblings, with the strongest association between OCS and (subclinical) positive symptoms. Within-subjects, substantial variability and co-variation of all symptom domains was found. Particularly, between-subject differences in positive symptoms and within-subject change in depressive symptoms predicted subsequent OCS in patients 1 months later. This is the first prospective study disaggregating between and within-subject associations between co-occurring OCS and symptom cluster of psychosis. Differences on these two levels suggest different underlying mechanisms. The association between depressive symptoms and subsequent increase/decrease of OCS within patients may have important treatment implications.status: publishe