One‐year metreleptin improves insulin secretion in patients with diabetes linked to genetic lipodystrophic syndromes

Recombinant methionyl human leptin (metreleptin) therapy was shown to improve hyperglycaemia, dyslipidaemia and insulin sensitivity in patients with lipodystrophic syndromes, but its effects on insulin secretion remain controversial. We used dynamic intravenous (i.v.) clamp procedures to measure insulin secretion, adjusted to insulin sensitivity, at baseline and after 1 year of metreleptin therapy, in 16 consecutive patients with lipodystrophy, diabetes and leptin deficiency. Patients, with a mean [± standard error of the mean (s.e.m.)] age of 39.2 (±4) years, presented with familial partial lipodystrophy (n = 11, 10 women) or congenital generalized lipodystrophy (n = 5, four women). Their mean (± s.e.m.) BMI (23.9 ± 0.7 kg/m²), glycated haemoglobin levels (8.5 ± 0.4%) and serum triglycerides levels (4.6 ± 0.9 mmol/l) significantly decreased within 1 month of metreleptin therapy, then remained stable. Insulin sensitivity (from hyperglycaemic or euglycaemic‐hyperinsulinaemic clamps, n = 4 and n = 12, respectively), insulin secretion during graded glucose infusion (n = 12), and acute insulin response to i.v. glucose adjusted to insulin sensitivity (disposition index, n = 12), significantly increased after 1 year of metreleptin therapy. The increase in disposition index was related to a decrease in percentage of total and trunk body fat. Metreleptin therapy improves not only insulin sensitivity, but also insulin secretion in patients with diabetes attributable to genetic lipodystrophies.     

圆二色谱在单萜和木脂体化合物结构分析中的应用

报道了10个化合物的CD谱,其中栀子酮(1)、栀二醇(2)和木脂体(3～7)均为新化合物。应用5种规则,确定了它们的绝对构型。     

小檗碱对局灶性脑缺血大鼠血小板聚集及血浆TXB2和6－keto－PGF1a水平的影响

以大鼠可逆性大脑中动脉梗塞（ＭＣＡＯ）致局灶性脑缺血为模型，观察小檗碱对大鼠ＭＣＡＯ２４ｈ后血小板粘附、聚集、血栓形成及血浆ＴＸＢ２和ＰＧＩ２生成的影响。结果表明，小檗碱２０ｍｇ·ｋｇ－１·ｄ－１ｉｐｌ，３或５ｄ，明显降低ＭＣＡｏ２４ｈ后血小板粘附性及ＡＤＰ、胶原和花生四烯酸诱导的血小板聚集率，抑制血浆ＴＸＢ２水平。同剂量ｉｐ３或５ｄ，则抑制血栓形成。提示小檗碱可能通过其抗血小板粘附和聚集及影响花生四烯酸代谢而发挥抗脑缺血作用。     

The impact of motherless paternity testing in a South African population

BackgroundPaternity investigations play an important role in determining biological relatedness, and in South Africa, the outcome of these investigations impacts medical, judicial and home affairs decisions. Short Tandem Repeat (STR) analysis is utilised to perform paternity and kinship analysis, due to the polymorphic nature of STR loci. The cost associated with paternity testing is high, and there is a demand for motherless testing.ObjectivesThis study aims to determine what the impact of motherless testing would have been by evaluating 6182 paternity trio cases.MethodsThe AmpFLSTR™ Identifiler™ PCR Amplification kit was used to profile each of the trio cases. A scenario was created where the mother was eliminated from the test results to determine if the paternity outcome would change.ResultsPutative fathers were excluded in 27% of all cases, and in 2.5% of those cases, putative fathers would have been falsely included, had the mother not been tested. These false inclusions are attributed to coincidental STR loci that are shared between the mother and the putative father. The addition of loci to the STR profiling kit may resolve the issue; however, comparable STR data with more loci will have to be evaluated to ensure it overcomes the issue of coincidentally shared loci between unrelated individuals.ConclusionWe would recommend that within our setup and within similar setups, the mother always be included for testing, except in extreme scenarios such as death. False inclusion of putative fathers could have serious legal implications for testing laboratories.     

A novel role for the metabotropic glutamate receptor-7: modulation of faecal water content and colonic electrolyte transport in the mouse

Background and purpose:

Increasing evidence implicates metabotropic glutamate receptor mGlu₇ in the pathophysiology of stress-related disorders such as depression and anxiety. Mood disorders are frequently associated with gastrointestinal (GI) dysfunction; however, the role of mGlu₇ receptors outside the CNS is unknown. This present study investigated the expression and possible functional role of mGlu₇ receptors in the mouse colon.

Experimental approach:

Expression of mGlu₇ receptor mRNA and protein was studied in mouse colon by in situ hybridization and Western blotting. Effects of the selective mGlu₇ receptor agonist AMN082 on defecation and faecal parameters were studied in an isolation-induced stress model. AMN082 effects on ion transport and neuronal intracellular signalling were examined via Ussing chambers and calcium imaging.

Key results:

mGlu₇ receptor mRNA and protein were highly expressed in colon mucosa. Stress-induced faecal output was unaffected by AMN082, although faecal water content was increased. In mucosa/submucosa preparations, 100 nM and 1 µM AMN082 increased bethanechol-induced changes in short-circuit current in the Ussing chamber. This was sensitive to tetrodotoxin. Also, 100 nM AMN082 significantly increased calcium signalling in a subset of submucosal neurons.

Conclusions and implications:

Activating mGlu₇ receptors increased colonic secretory function in vivo and ex vivo. In a group of submucosal neurons, AMN082 strongly induced calcium signalling and the presence of submucosal nerves was required for the AMN082-dependent increase in secretion. These data suggest that targeting mGlu₇ receptors may be useful in the treatment of central components of stress disorders and also stress-associated GI dysfunction such as diarrhoea or constipation.     

A novel, orally active LPA1 receptor antagonist inhibits lung fibrosis in the mouse bleomycin model

Background and purpose:

The aim of this study was to assess the potential of an antagonist selective for the lysophosphatidic acid receptor, LPA₁, in treating lung fibrosis We evaluated the in vitro and in vivo pharmacological properties of the high affinity, selective, oral LPA₁-antagonist (4′-{4-[(R)-1-(2-chloro-phenyl)-ethoxycarbonylamino]-3-methyl-isoxazol-5-yl}-biphenyl-4-yl)-acetic acid (AM966).

Experimental approach:

The potency and selectivity of AM966 for LPA₁ receptors was determined in vitro by calcium flux and cell chemotaxis assays using recombinant and native cell cultures. The in vivo efficacy of AM966 to reduce tissue injury, vascular leakage, inflammation and fibrosis was assessed at several time points in the mouse bleomycin model.

Key results:

AM966 was a potent antagonist of LPA₁ receptors, with selectivity for this receptor over the other LPA receptors. In vitro, AM966 inhibited LPA-stimulated intracellular calcium release (IC₅₀ = 17 nM) from Chinese hamster ovary cells stably expressing human LPA₁ receptors and inhibited LPA-induced chemotaxis (IC₅₀ = 181 nM) of human IMR-90 lung fibroblasts expressing LPA₁ receptors. AM966 demonstrated a good pharmacokinetic profile following oral dosing in mice. In the mouse, AM966 reduced lung injury, vascular leakage, inflammation and fibrosis at multiple time points following intratracheal bleomycin instillation. AM966 also decreased lactate dehydrogenase activity and tissue inhibitor of metalloproteinase-1, transforming growth factor β1, hyaluronan and matrix metalloproteinase-7, in bronchoalveolar lavage fluid.

Conclusions and implications:

These findings demonstrate that AM966 is a potent, selective, orally bioavailable LPA₁ receptor antagonist that may be beneficial in treating lung injury and fibrosis, as well as other diseases that are characterized by pathological inflammation, oedema and fibrosis.     

Challenges of Francisella classification exemplified by an atypical clinical isolate

The accumulation of sequenced Francisella strains has made it increasingly apparent that the 16S rRNA gene alone is not enough to stratify the Francisella genus into precise and clinically useful classifications. Continued whole-genome sequencing of isolates will provide a larger base of knowledge for targeted approaches with broad applicability. Additionally, examination of genomic information on a case-by-case basis will help resolve outstanding questions regarding strain stratification. We report the complete genome sequence of a clinical isolate, designated here as F. novicida-like strain TCH2015, acquired from the lymph node of a 6-year-old male. Two features were atypical for F. novicida: exhibition of functional oxidase activity and additional gene content, including proposed virulence determinants. These differences, which could potentially impact virulence and clinical diagnosis, emphasize the need for more comprehensive methods to profile Francisella isolates. This study highlights the value of whole-genome sequencing, which will lead to a more robust database of environmental and clinical genomes and inform strategies to improve detection and classification of Francisella strains.