203Pb-labeled alpha-melanocyte-stimulating hormone peptide as an imaging probe for melanoma detection.

Peptide-targeted alpha-therapy with 7.4 MBq of (212)Pb-[1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid]-ReO-[Cys(3,4,10),d-Phe(7),Arg(11)]alpha-MSH(3-13) ((212)Pb-DOTA-Re(Arg(11))CCMSH) cured 45% of B16/F1 murine melanoma-bearing C57 mice in a 120-d study, highlighting its melanoma treatment potential. However, there is a need to develop an imaging surrogate for patient-specific dosimetry and to monitor the tumor response to (212)Pb-DOTA-Re(Arg(11))CCMSH therapy. The purpose of this study was to evaluate the potential of (203)Pb-DOTA-Re(Arg(11))CCMSH as a matched-pair SPECT agent for (212)Pb-DOTA-Re(Arg(11))CCMSH. METHODS: DOTA-Re(Arg(11))CCMSH was labeled with (203)Pb in 0.5 M NH(4)OAc buffer at pH 5.4. The internalization and efflux of (203)Pb-DOTA-Re(Arg(11))CCMSH were determined in B16/F1 melanoma cells. The pharmacokinetics of (203)Pb-DOTA-Re(Arg(11))CCMSH was examined in B16/F1 melanoma-bearing C57 mice. A micro-SPECT/CT study was performed with (203)Pb-DOTA-Re(Arg(11))CCMSH in a B16/F1 melanoma-bearing C57 mouse at 2 h after injection. RESULTS: (203)Pb-DOTA-Re(Arg(11))CCMSH was easily prepared in NH(4)OAc buffer and completely separated from the excess nonradiolabeled peptide by reversed-phase high-performance liquid chromatography (RP-HPLC). (203)Pb-DOTA-Re(Arg(11))CCMSH displayed fast internalization and extended retention in B16/F1 cells. Approximately 73% of (203)Pb-DOTA-Re(Arg(11))CCMSH activity internalized after a 20-min incubation at 25 degrees C. After incubation of the cells in culture medium for 20 min, 78% of internalized activity remained in the cells. (203)Pb-DOTA-Re(Arg(11))CCMSH exhibited a biodistribution pattern similar to that of (212)Pb-DOTA-Re(Arg(11))CCMSH in B16/F1 melanoma-bearing mice. (203)Pb-DOTA-Re(Arg(11))CCMSH exhibited a peak tumor uptake of 12.00+/-3.20 percentage injected dose per gram (%ID/g) at 1 h after injection. The tumor uptake gradually decreased to 3.43+/-1.12 %ID/g at 48 h after injection. (203)Pb-DOTA-Re(Arg(11))CCMSH exhibited a peak tumor-to-kidney uptake ratio of 1.53 at 2 h after injection. The absorbed doses to the tumor and kidneys were 4.32 and 4.35 Gy, respectively, per 37 MBq. Whole-body clearance of (203)Pb-DOTA-Re(Arg(11))CCMSH was fast, with approximately 89% of the injected activity cleared through the urinary system by 2 h after injection. (203)Pb showed 1.6-mm SPECT resolution, which was comparable to (99m)Tc. Melanoma lesions were visualized through SPECT/CT images of (203)Pb-DOTA-Re(Arg(11))CCMSH at 2 h after injection. CONCLUSION: (203)Pb-DOTA-Re(Arg(11))CCMSH exhibited favorable pharmacokinetic and tumor imaging properties, highlighting its potential as a matched-pair SPECT agent for (212)Pb-DOTA-Re(Arg(11))CCMSH melanoma treatment.     

Transgenic mice expressing constitutive active MAPKAPK5 display gender-dependent differences in exploration and activity

Background  

The mitogen-activated protein kinases, MAPKs for short, constitute cascades of signalling pathways involved in the regulation of several cellular processes that include cell proliferation, differentiation and motility. They also intervene in neurological processes like fear conditioning and memory. Since little remains known about the MAPK-Activated Protein Kinase, MAPKAPK5, we constructed the first MAPKAPK knockin mouse model, using a constitutive active variant of MAPKAPK5 and analyzed the resulting mice for changes in anxiety-related behaviour.     

Progressive myoclonic ataxia with intrathecal immune activation in six patients

In six patients with slowly progressive sporadic cerebellar ataxia and cortical multifocal action myoclonus, cerebrospinal fluid (CSF) IgG index was persistently very high (1.2–6.7) and numerous oligoclonal bands were detected. Progressive cognitive impairment and MRI cerebellar and cerebral atrophy were observed. No serum antibodies were found. Various degenerative, metabolic, inflammatory and systemic diseases were excluded. The cerebellum may be the main target of a degenerative or immune process and releases antigens that, enhancing a compartmentalised (auto)immune response, as suggested by the persistent intrathecal activation, could lead to further cerebellar damage. As the frequency of CSF oligoclonal banding in myoclonic ataxia is unknown, our patients’ disease might represent a hitherto unreported entity or a subset of progressive myoclonic ataxia.

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Sommario Descriviamo sei pazienti con atassia cerebellare sporadica e mioclono corticale d’azione multifocale, nel cui liquor i valori dell’indice IgG si mantenevano persistentemente elevati ed erano presenti numerose bande oligoclonali. I pazienti manifestavano un progressivo declino cognitivo e la RM mostrava atrofia cerebellare e cerebrale. In assenza di anticorpi identificabili non era possibile formulare una diagnosi di malattia nota. Suggeriamo che il cervelletto possa essere il principale bersaglio di un processo degenerativo o immuno-mediato e che gli antigeni liberati inducano la produzione di anticorpi che ulteriormente provocano danno cerebrale. Poiché non è nota la frequenza delle bande oligoclonali nel liquor di pazienti con atassia mioclonica, non sappiamo se la malattia qui descritta sia una entità nuova o un sottogruppo delle atassie miocloniche.

     

Torasemide, a new loop diuretic, in patients with chronic renal failure

Torasemide, a new loop diuretic, was administered in 9 hospitalized patients with chronic renal failure to treat both arterial hypertension and peripheral edema. The urine of 5 patients was collected over 12-hour periods to assess the long-lasting diuretic activity of torasemide. Torasemide induced a significant decrease in blood pressure and reversion of peripheral edema in all patients without adverse effects. Torasemide is a high-ceiling loop diuretic, useful in correcting extracellular fluid volume expansion in patients with chronic renal failure.     

Cerebral MR findings in tuberous sclerosis

Cerebral magnetic resonance (MR) and CT findings of two sisters affected by clinically defined tuberous sclerosis are reported. Magnetic resonance showed a greater number of lesions than did CT. In addition, MR depiction of the abnormalities better corresponded to the pathological findings usually described in this disease.     

Diffusion-weighted imaging study of patients with essential tremor.

The pathophysiology of essential tremor (ET) is unknown. PET and fMRI studies have revealed bilateral activation and (1)H-MRS studies metabolic abnormalities in the cerebellum and other functionally related brain structures in ET. Diffusion-weighted imaging (DWI) was used to search for evidence of tissue integrity abnormalities in these areas in ET patients and 10 matched controls by calculating water apparent diffusion coefficients (ADCs). Regions of interest included the left and right cerebellum, red nucleus, thalamus, caudate, putamen, pallidum, and frontal white matter. Histograms of ADCs were generated for all pixels in the infratentorial compartment and manually segmented areas corresponding to brainstem, vermis, and cerebellar hemispheres. ADC values were similar in all brain areas in patients and controls. Our study did not detect changes affecting the investigated brain regions in ET patients. These findings argue against major structural damage in the ET brain, although more subtle neurodegenerative changes cannot be ruled out.