125I]17-alpha-iodovinyl 11-beta-methoxyestradiol interaction in vivo with estrogen receptors in hormone-independent MCF-7 human breast cancer transfected with the v-rasH oncogene

[125I]17-alpha-Iodovinyl 11-beta-methoxyestradiol [( 125I]MIVE2) has been evaluated as a potential radiotracer for the diagnostic imaging of estrogen receptor (ER)-positive human breast cancer. In vivo distribution experiments with athymic ovariectomized nude mice bearing human breast tumors revealed an apparent correlation between uptake of 125I-labeled compound and estrogen receptor concentration in the tumors. At 4 h after i.v. injection of [125I]MIVE2, HS578T (ER negative), ZR75-B (intermediate ER), and MCF-7ras (high ER) tumors accumulated 0.320 +/- 0.186, 0.679 +/- 0.467, and 2.6163 +/- 1.0121% injected dose/g, respectively. With coinjection of unlabeled 17-beta-estradiol, levels of radioactivity in MCF-7ras tumors were decreased to 0.4859 +/- 0.1424% injected dose/g, indicating a receptor-mediated process. Peak activity of radioligand in MCF-7ras tumors and uteri was observed at 2 h and was retained for the 8-h time course. Blood and nontarget tissue, such as muscle, revealed a rapid clearance of 125I-labeled compound by 8 h. Eight hours after injection, uterus and tumor-to-blood ratios were calculated to be 225 and 21, respectively. Also, MCF-7ras tumors were shown to accumulate 6.5-fold more radioactivity than muscle. These data suggest that [125I]MIVE2 has the capability of interacting specifically and with high affinity with estrogen receptors in human breast tumors in nude mice and may possibly be used for imaging receptor-positive tumors in breast cancer patients with very low serum estrogen levels. Selective uptake of compound in MCF-7ras tumors emphasizes the usefulness of an estrogen receptor-positive tumor model which has a unique ability to grow in a host system without circulating estrogens.     

Lysophosphatidic acid impairs glucose homeostasis and inhibits insulin secretion in high-fat diet obese mice

Aims/hypothesis

Lysophosphatidic acid (LPA) is a lipid mediator produced by adipocytes that acts via specific G-protein-coupled receptors; its synthesis is modulated in obesity. We previously reported that reducing adipocyte LPA production in high-fat diet (HFD)-fed obese mice is associated with improved glucose tolerance, suggesting a negative impact of LPA on glucose homeostasis. Here, our aim was to test this hypothesis.

Methods

First, glucose tolerance and plasma insulin were assessed after acute (30 min) injection of LPA (50 mg/kg) or of the LPA1/LPA3 receptor antagonist Ki16425 (5 mg?kg^?1?day^?1, i.p.) in non-obese mice fed a normal diet (ND) and in obese/prediabetic (defined as glucose-intolerant) HFD mice. Glucose and insulin tolerance, pancreas morphology, glycogen storage, glucose oxidation and glucose transport were then studied after chronic treatment (3 weeks) of HFD mice with Ki16425.

Results

In ND and HFD mice, LPA acutely impaired glucose tolerance by inhibiting glucose-induced insulin secretion. These effects were blocked by pre-injection of Ki16425 (5 mg/kg, i.p.). Inhibition of glucose-induced insulin secretion by LPA also occurred in isolated mouse islets. Plasma LPA was higher in HFD mice than in ND mice and Ki16425 transiently improved glucose tolerance. The beneficial effect of Ki16425 became permanent after chronic treatment and was associated with increased pancreatic islet mass and higher fasting insulinaemia. Chronic treatment with Ki16425 also improved insulin tolerance and increased liver glycogen storage and basal glucose use in skeletal muscle.

Conclusions/interpretation

Exogenous and endogenous LPA exerts a deleterious effect on glucose disposal through a reduction of plasma insulin; pharmacological blockade of LPA receptors improves glucose homeostasis in obese/prediabetic mice.     

Absence of linkage to 8q24 in a European family with familial adult myoclonic epilepsy (FAME)

BACKGROUND: Familial adult myoclonic epilepsy (FAME) is defined by autosomal dominant inheritance, adult onset of myoclonus of the extremities, infrequent epileptic seizures, nonprogressive course, abnormality of polyspikes and waves on examination by EEG and photosensitivity, giant somatosensory evoked potentials, enhancement of C reflex, and premyoclonus spike detected by means of the jerk-locked averaging EEG method. These findings were also observed in patients with benign adult familial myoclonic epilepsy (BAFME) and patients with familial cortical tremor. FAME and BAFME have been described only in Japan. The genes responsible for FAME and BAFME were mapped in the same genetic interval in 8q22.3-q24.1 OBJECTIVE: To study clinical and genetic characteristics of a European family with FAME. METHODS: A four-generation European kindred presenting with FAME, including 18 members, is described. Clinical analysis was performed on 15 living subjects and electrophysiologic study on 5 patients. Linkage analysis was performed with fluorescent microsatellites encompassing the FAME/BAFME locus (8q23.3-q24.1). RESULTS: Ten living and three deceased relatives had the clinical characteristics of FAME. Mean age at onset of the 10 living patients was 41 years (range, 30-60 years). Eight of the 13 affected subjects had generalized tonic-clonic seizures. Electrophysiologic studies confirmed the diagnosis of FAME in the five patients studied. The pattern of inheritance was consistent with an autosomal dominant inheritance. The locus responsible for FAME/BAFME was excluded. CONCLUSION: Observation of a European family extends the occurrence of familial adult myoclonic epilepsy to non-Japanese patients. Exclusion of linkage of this family to the locus for familial adult myoclonic epilepsy/benign adult familial myoclonic epilepsy established the genetic heterogeneity of this disorder.     

Epidermal growth factor receptor gene analysis in renal cell carcinoma

The epidermal growth factor receptor binds the mitogens epidermal growth factor and transforming growth factor-alpha. Increased expression of the epidermal growth factor receptor has been noted in many types of tumors and is associated with gene amplification in several including epidermoid carcinoma, lung carcinoma, breast carcinoma and glioblastoma. We have recently observed increased expression of the epidermal growth factor receptor messenger RNA in neoplastic tissue relative to normal kidney tissue from patients with renal cell carcinoma. To determine if epidermal growth factor receptor gene amplification was present in renal cell carcinoma, DNA was extracted from renal cell carcinoma cell lines and from normal kidney and renal cell carcinoma tissues derived from radical nephrectomy specimens from thirty patients. DNA was analyzed by Southern blot hybridization. There was no epidermal growth factor receptor gene amplification detected in the renal cell carcinoma samples studied, indicating the increased epidermal growth factor gene expression observed in renal cell carcinoma does not occur through gene amplification. Unlike other tumors with enhanced epidermal growth factor receptor gene expression, amplification of this gene does not appear to be a common feature of renal cell carcinoma.     

Apelin stimulates glucose uptake but not lipolysis in human adipose tissue ex vivo

Apelin is a peptide present in different cell types and secreted by adipocytes in humans and rodents. Apelin exerts its effects through a G-protein-coupled receptor called APJ. During the past years, a role of apelin/APJ in energy metabolism has emerged. Apelin was shown to stimulate glucose uptake in skeletal muscle through an AMP-activated protein kinase (AMPK)-dependent pathway in mice. So far, no metabolic effects of apelin have been reported on human adipose tissue (AT). Thus, the effect of apelin on AMPK in AT was measured as well as AMPK-mediated effects such as inhibition of lipolysis and stimulation of glucose uptake. AMPK and acetyl-CoA carboxylase phosphorylation were measured by western blot to reflect the AMPK activity. Lipolysis and glucose uptake were measured, ex vivo, in response to apelin on isolated adipocytes and explants from AT of the subcutaneous region of healthy subjects (body mass index: 25.6 ± 0.8 kg/m(2), n = 30 in total). APJ mRNA and protein are present in human AT and isolated adipocytes. Apelin stimulated AMPK phosphorylation at Thr-172 in a dose-dependent manner in human AT, which was associated with increased glucose uptake since C compound (20 μM), an AMPK inhibitor, completely prevented apelin-induced glucose uptake. However, in isolated adipocytes or AT explants, apelin had no significant effect on basal and isoprenaline-stimulated lipolysis. Thus, these results reveal, for the first time, that apelin is able to act on human AT in order to stimulate AMPK and glucose uptake.     

Diagnostic performance of sacroiliac and spinal MRI for the diagnosis of non-radiographic axial spondyloarthritis in patients with inflammatory back pain

ObjectiveThe lack of specificity of the ASAS MRI criteria for non-radiographic axial spondylarthritis (NR-axSpA) justifies the evaluation of the discriminatory capacity of other MRI abnormalities in the sacroiliac joints and dorsolumbar spine.MethodsIn patients hospitalized for inflammatory lumbar back pain, the diagnostic performance (sensitivity, specificity, positive likelihood ratio (PLR)) of MRI abnormalities was calculated using the rheumatologist expert opinion as a reference: (i) sacroiliac joints: Bone marrow edema (BME) (number and location), extended edema > 1 cm (deep lesion), fatty metaplasia (number), erosion (number and location), backfill. (ii) Dorsolumbar spine: BME (number and location), fatty metaplasia (number), posterior segment involvement.ResultsIn this prospective cohort, 40 NR-axSpA cases and 79 other diagnoses were included. The presence of at least 3 inflammatory signals in the sacroiliac joints (PLR: 25.67 [95% CI: 3.48–48.9]), the presence of at least one sacroiliac erosion (PLR: 12.80 [3.04–54]), the combination of an inflammatory signal and sacroiliac erosion (PLR: 11.85 [2.79–50]), the combination of deep lesion and fatty metaplasia (PLR: 15.80 [2.05–121.9]) or erosion (PLR: 11.86 [1.47–95.01]) had the best diagnostic performance. The combination of spinal and sacroiliac MRI criteria significantly increased diagnostic performance for the diagnosis of NR-axSpA.ConclusionWhen NR-axSpA is suspected, in addition to the presence and number of inflammatory lesions, MRI interpretation should include the location and the extent of the sacroiliac lesions, the presence of erosion or fatty metaplasia, and anterior involvement of the lumbar spine.