Molecular characterization of a recently identified circovirus in zebra finches (Taeniopygia guttata) associated with immunosuppression and opportunistic infections

A recently identified circovirus (family Circoviridae) was detected in 14 zebra finches (Taeniopygia guttata) from seven aviaries and hobbyist breeders using polymerase chain reaction followed by sequencing. Full genome sequences of virus strains from six zebra finches consistently revealed characteristic circoviral genomic features such as a stem-loop structure and two major open reading frames (ORFs) encoding the replication-associated protein and the putative capsid protein. One further ORF encoding a protein of unknown function was additionally identified in all six genomes. Based on full genome nucleotide comparison, zebra finch circovirus was most similar to Finch circovirus originating from a Gouldian finch (Chloebia gouldiae) sharing 78% nucleotide identity. High genetic diversity was detected in the circoviruses from individual zebra finches. Comparison of the six full genome sequences revealed two genetic subgroups, which shared pairwise nucleotide identities between 91.4% and 92.7%. Analyses including partial sequences of the replication-associated protein gene of the zebra finch circovirus strains from all 14 birds supported the existence of two main clusters. Clinical diseases associated with circovirus infection were found in nestlings, fledglings and adult birds and varied from mild to severe with high mortality caused by secondary infections. Macrorhabdus ornithogaster was the most frequently detected opportunistic pathogen. Feathering disorders were seen in two birds. Lymphocytic depletion of the spleen and leukocytopaenia were detected in individual birds, suggesting immunosuppression and a pathogenesis common to circovirus infections in other birds.     

Transcapillary escape rate and albuminuria in Type II diabetes. Effects of short-term treatment with low-molecular weight heparin (Short Communication)

Summary The relation between urinary albumin excretion rate (UAE), transcapillary escape rate of albumin (TER_alb), haemostatic factors, ambulatory blood pressure, and metabolic variables was investigated in 45 Type II (non-insulin-dependent) diabetic patients without overt nephropathy or uncontrolled blood pressure. We enrolled 44 patients in a placebo controlled study to test the effects of 3 week long treatment with low-molecular weight heparin (tinzaparin) on the same variables. BMI, 24 h systolic and diastolic blood pressure, plasma concentrations of triglycerides, fasting glucose, factor VIII, von Willebrand factor (vWf), fibrinogen, α-2 macroglobulin, and fibronectin were notably higher in patients with increased albuminuria compared with normoalbuminuric patients, whereas the TER_alb was similar in the two groups. TER_alb correlated with fasting plasma glucose. UAE correlated more closely than TER_alb with 24 h ambulatory blood pressure, vWf, and factor VIII. Urinary albumin excretion rate was unchanged during tinzaparin [28.9 ± 5.6 vs 28.1 ± 6.0 μg/min (geometric mean (antilog SD)] vs placebo (18.0 ± 5.4 vs 17.6 ± 5.3 μg/min), and no change was found in TER_alb [6.3 ± 1.6 vs 6.0 ± 1.5 %/h (means ± SD), and 6.3 ± 1.5 vs 5.6 ± 1.8 %/h; tinzaparin versus placebo, respectively]. Only minor changes were observed in blood pressure, lipids, glycaemic control and haemostatic factors. This study shows no correlation between albuminuria and transcapillary escape rate in Type II diabetic patients without overt nephropathy or uncontrolled blood pressure. UAE is related to markers of atherosclerosis, endothelial injury and dysfunction, and haemostatic factors. Moreover, UAE correlates much more than TER_alb with 24 h ambulatory blood pressure, von Willebrand factor, and factor VIII. Finally, short-term treatment with tinzaparin does not change the transvascular or glomerular leakage of albumin. These results indicate that TER_alb is not a sensitive marker of microvascular dysfunction in such patients and that factors other than abnormal glycosaminoglycan metabolism may contribute to the vascular damage of these patients. [Diabetalogia (1999) 42: 60–67] Received: 2 February 1998 and in final revised form: 1 September 1998     

Acute effects of ghrelin administration on glucose and lipid metabolism

CONTEXT: Ghrelin infusion increases plasma glucose and nonesterified fatty acids, but it is uncertain whether this is secondary to the concomitant release of GH. OBJECTIVE: Our objective was to study direct effects of ghrelin on substrate metabolism. DESIGN: This was a randomized, single-blind, placebo-controlled two-period crossover study. SETTING: The study was performed in a university clinical research laboratory. PARTICIPANTS: Eight healthy men aged 27.2 +/- 0.9 yr with a body mass index of 23.4 +/- 0.5 kg/m(2) were included in the study. INTERVENTION: Subjects received infusion of ghrelin (5 pmol x kg(-1) x min(-1)) or placebo for 5 h together with a pancreatic clamp (somatostatin 330 microg x h(-1), insulin 0.1 mU x kg(-1) x min(-1), GH 2 ng x kg(-1) x min(-1), and glucagon 0.5 ng.kg(-1) x min(-1)). A hyperinsulinemic (0.6 mU x kg(-1) x min(-1)) euglycemic clamp was performed during the final 2 h of each infusion. RESULTS: Basal and insulin-stimulated glucose disposal decreased with ghrelin [basal: 1.9 +/- 0.1 (ghrelin) vs. 2.3 +/- 0.1 mg x kg(-1) x min(-1), P = 0.03; clamp: 3.9 +/- 0.6 (ghrelin) vs. 6.1 +/- 0.5 mg x kg(-1) x min(-1), P = 0.02], whereas endogenous glucose production was similar. Glucose infusion rate during the clamp was reduced by ghrelin [4.0 +/- 0.7 (ghrelin) vs. 6.9 +/- 0.9 mg.kg(-1) x min(-1); P = 0.007], whereas nonesterified fatty acid flux increased [131 +/- 26 (ghrelin) vs. 69 +/- 5 micromol/min; P = 0.048] in the basal period. Regional lipolysis (skeletal muscle, sc fat) increased insignificantly with ghrelin infusion. Energy expenditure during the clamp decreased after ghrelin infusion [1539 +/- 28 (ghrelin) vs. 1608 +/- 32 kcal/24 h; P = 0.048], but the respiratory quotient did not differ. Minor but significant elevations in serum levels of GH and cortisol were observed after ghrelin infusion. CONCLUSIONS: Administration of exogenous ghrelin causes insulin resistance in muscle and stimulates lipolysis; these effects are likely to be direct, although a small contribution of GH and cortisol cannot be excluded.     

Dosing Accuracy of Two Disposable Insulin Pens According to New ISO 11608-1: 2012 Requirements

Objective:

The aim was to compare 2 disposable insulin pens, FlexTouch® (Novo Nordisk, insulin aspart) and SoloSTAR® (Sanofi, insulin glulisine), according to new ISO 11608-1:2012 requirements for dosing accuracy.

Methods:

Sixty pens of each type were tested at 1, 40, and 80 U doses. Following the new ISO requirements, each dose was delivered from the front, middle, and rear one-third of the pen. Statistical analysis was performed using Student’s t test.

Results:

Both pens delivered all doses within ISO limits. The difference between the average measured dose and the target dose was significantly smaller for SoloSTAR than FlexTouch at 40 U (P = .009) and 80 U (P = .008), but not at 1 U (P = .417).

Conclusion:

Both insulin pens fulfilled the dosing accuracy requirements defined by ISO 11608-1:2012 at all 3 dosage levels.     

Influence of growth hormone on glucose-induced glucose uptake in normal men as assessed by the hyperglycemic clamp technique

To determine whether physiological increments in circulating GH concentrations influence glucose-induced glucose uptake (GIGU), two-step sequential hyperglycemic clamp (plasma glucose, 6 and 14 mmol/L) studies were performed in six normal subjects with and without GH infusion (40 ng/kg.min). The latter resulted in serum GH levels of 15 +/- 1 (+/- SE) microgram/L. Infusion of somatostatin (250 micrograms/h during step 1 and 750 micrograms/h during step 2) together with a replacement dose of insulin (1.1 pmol/kg.min) resulted in serum insulin levels comparable to basal levels in both studies. The GIGU ([3-3H]glucose), assessed as the difference between steps 2 and 1 glucose utilization during the final 60 min of each step (150 min) was markedly impaired during GH infusion (with GH, 1.1 +/- 0.2 mg/kg.min; without GH, 3.1 +/- 0.3 mg/kg.min; P less than 0.001). Moreover, the percent increase in glucose uptake was considerably reduced during hypersomatotropinemia (with GH, 44 +/- 9%; without GH, 97 +/- 11%; P less than 0.01). In the GH infusion as well as control studies, endogenous glucose production (EGP) was similar at the two levels of glycemia, whereas GH infusion approximately doubled EGP [2.3 +/- 0.2 vs. 1.1 +/- 0.3 mg/kg.min and 2.0 +/- 0.4 vs. 1.1 +/- 0.4 mg/kg.min (step 1 and 2, respectively)]. We conclude that moderate hypersomatotropinemia for several hours is characterized by impaired GIGU as well as augmented EGP.     

Angiogenic factors stimulate mast-cell migration

Mast cells accumulate at sites of angiogenesis. The factor(s) that control mast-cell recruitment at these sites have yet to be defined. We sought to determine if angiogenic factors result in mast-cell chemotaxis. In this study, we observed that platelet-derived growth factor-AB (PDGF-AB), vascular endothelial cell growth factor (VEGF), and basic fibroblast growth factor (bFGF) each cause directed migration of murine mast cells at picomolar concentrations, with a typical bell- shaped dose-response curve. Another potent angiogenic factor, platelet- derived endothelial cell growth factor (PD-ECGF), appears to promote chemokinesis of mast cells, whereas tumor necrosis factor-alpha, a weak angiogenic factor, is less robust but still functions as a mast cell chemotactic factor. Epidermal growth factor (EGF), a growth factor with minimal angiogenic properties, was ineffective as a mast cell chemotactic factor. A checkerboard analysis confirmed the directional chemotactic response of PDGF-AB, VEGF, and bFGF, while indicating the chemokinetic response induced by PD-ECGF. Cross-desensitization of growth-factor-induced directed migration was observed between PDGF-AB and bFGF, and also between PDGF-AB and PD-ECGF. Tyrosine kinase- inhibitor genistein effectively dampened the chemotactic responses, whereas pertussis toxin had no effect. In summary, our findings suggest that factors known to act on endothelial cells and stimulate neovascularization may simultaneously serve to recruit mast cells to these sites. The local accumulation of mast cells is believed to facilitate new vessel formation through complex cell:cell interactions.