Circadian rhythm of serum and tissue lipids in the rat: the effect of limited access to food

Young male Wistar rats of a conventional breed were kept 4 weeks in a separate room with a light: dark regimen of 12:12 h. Some were fed ad libitum (group C, the control), some were meal-fed from 8.30 to 10.30 a.m. (group A) and the others were meal-fed from 8.30 to 10.30 p.m. (group B). When adapted to the nutritional regimen the animals were decapitated at 3-hour intervals, starting at 8 a.m., and their serum and epididymal tissue non-esterified fatty acid values, their serum and liver triacylglycerol and total cholesterol levels and their serum phospholipid concentration were determined. Limitation of the period for which they had access to food at different times of the day significantly synchronized the circadian oscillations of their serum and tissue lipid levels. The most pronounced differences in the form of the antiphase position of the maxima of the curves in groups A and B, or A and C, were recorded in the oscillations of the serum and white adipose non-esterified fatty acid values, in serum triacylglycerol levels and in liver cholesterol levels. It is reasonable to assume that the synchronizing role of timed meal-feeding will be subject to the influence of seasonal factors.     

Circadian rhythm of blood leptin level in obese and non-obese people

Leptin, an adipose tissue hormone, has circadian variations in its secretion. Aims of this study were to show how circadian rhythm depends on fat tissue distribution in obese and non-obese subjects. The research was carried out on 70 subjects (37 men and 33 women) with an average body mass index (BMI) of 25.22 kg/m2. Concentration of leptin in blood was measured at 8.30 a.m., 12.30 p.m. and 6.30 p.m. Basal leptin level correlated strongly with all isolated regions of subcutaneous fat tissue in women and obese subjects. Circadian changes of blood leptin level in non-obese people are more significant than these changes in obese people. Differences in circadian pattern of leptin secretion between obese and non-obese subjects were probably caused by enlarged volume of subcutaneous fat tissue in obese people. Lean subjects have subcutaneous fat in physiological range which allows influence of some hormones (insulin or cortizol) or food intake on leptin secretion.     

The effect of long-distance running on plasma immunoreactive glucagon levels

Twelve highly conditioned long-distance runners were studied to determine the effects of marathon (42 km) and 10,000 m running on plasma immunoreactive glucagon (IRG), serum immunoreactive insulin (IRI), and serum glucose (G) levels. Blood samples were drawn just prior to and immediately upon completion of the run. Marathon running resulted in no significant change in G, IRI, or IRG levels. After running 10,000 m, plasma IRG levels did not change significantly, while IRI and G increased significantly. In evaluating the pooled data from both runs, a significant inverse correlation was observed between delta G and delta IRG. This relationship between delta G and delta IRG suggests that glucagon plays a role in maintaining normal blood glucose levels during strenuous exercise.     

Beta cell response to the hyperglycaemic clamp in three patients with insulinoma: a study using a hyperglycaemic glucose clamp

To determine the mechanism responsible for deficient carbohydrate metabolism in patients with insulinoma, we studied three affected patients and seven normal controls using the hyperglycaemic clamp method (8.4 mmol/l) with the BIOSTATOR (GCIIS). In insulinoma patients, the amount of glucose necessary to reach the hyperglycaemic clamp was less than that required in normal controls (6.19 +/- 1.19 mg/min/kg vs. 9.95 +/- 0.53 mg/min/kg) (p less than 0.05). There was no significant difference in metabolized glucose (M) in the stable phase of the hyperglycaemic clamp; however, the M/IRI in this phase was less in those with insulinoma (7.9 +/- 0.50) than in controls (22.26 +/- 4.14) (p less than 0.05). There was no difference in beta cell secretory response to hyperglycaemic stimulus (defined as the increase in the concentration of C-peptide from the basal state to the stable phase of the hyperglycaemic clamp) between the two groups. Hepatic insulin extraction was significantly lower in patients with insulinoma than in normal controls (+0.72 +/- 0.07 vs. +0.85 +/- 0.01). Finally, the ratios of fractional turnover of glucose (K/IRI); glucose clearance/IRI and total rate of elimination of glucose from the extracellular pool/IRI were also all lower in patients with insulinoma than in controls (p less than 0.05). These data support the conclusion that deficient glucose metabolism seen in these patients is not related to a lack of response to glucose on the part of normal or neoplastic islet tissue.(ABSTRACT TRUNCATED AT 250 WORDS)     

MiR-330-3p suppresses phosphoglycerate mutase family member 5 -inducted mitophagy to alleviate hepatic ischemia-reperfusion injury

Mitochondrial dysfunction plays a central role in hepatic ischemia-reperfusion injury (IRI). The significance of mitophagy in hepatic IRI remains poorly understood. The mechanisms that cause IRI are complex, and many factors are involved in the injury formation process. The miR-330-3p mediates cell proliferation, cell death, and metabolism in various organisms. In this study, the levels of miR-330-3p were significantly downregulated in hepatic IRI, and the number of autophagosomes was increased in response to IRI as obtained under both in vivo and in vitro conditions. These results demonstrate that a reduction in miR-330-3p expression represents an important factor involved with promoting hepatic IRI. Moreover, we found that miR-330-3p interacted with phosphoglycerate mutase family member 5 (PGAM5) to regulate mitophagy. In specific, an overexpression of miR-330-3p diminished PGAM5 levels, which promoted mitophagy in response to IRI. In contrast, a downregulation of miR-330-3p was associated with increased PGAM5 levels leading to increased mitophagy. In conclusion, miR-330-3p suppresses PGAM5-induced mitophagy to alleviate hepatic IRI. Such findings not only reveal some of the mechanistic basis for this microRNA in liver injury, but also provide a foundation for new therapeutic approaches in the treatment of this condition.     

Differential effects of body weight, hyperinsulinemia and oral glucose load on serum C-peptide/insulin molar ratio.

Serum C-peptide immunoreactivity (CPR)/immunoreactive insulin (IRI) molar ratio was determined in 136 subjects without renal, hepatic and thyroid disorders, at fasting, and during the initial period of 75 g-oral glucose tolerance test. The subjects were divided into 4 groups based on their body weight and age; Group A, young (< 55 years) and normal body weight (body mass index [BMI, kg/m2] < or = 25) subjects; Group B, young and overweight (BMI > 25) subjects; Group C, aged (> or = 55 years) and normal body weight (BMI < or = 25) subjects; Group D, aged and overweight subjects. Fasting CPR/IRI ratio and absolute CPR level negatively correlated in Groups B and D but not in A and C. After oral glucose load with elevation of insulin, CPR/IRI ratio invariably declined in all groups and significant negative correlation between CPR/IRI and CPR was found in Groups A, B and D but not in C. Slope of the regression lines obtained for correlation between CPR/IRI ratio and CPR were significantly steeper at fasting compared to the post-stimulation phase. CPR/IRI ratio is affected by hyperinsulinemia and oral glucose load but not by obesity alone. Assuming that CPR/IRI ratio reflects hepatic extraction of insulin, the insulin clearance at fasting is progressively reduced with increasing insulin secretion in overweight subjects: failure to detect such phenomenon in normal body weight subjects may be due to a narrower CPR range in this population. Insulin metabolism at fasting and during glucose stimulation is likely to be regulated by distinct factors.     

Insulin secretion and sensitivity in acromegaly

To examine the effect of excess growth hormones on carbohydrate metabolism, we studied glucose-stimulated insulin secretion and glucose utilization in 6 patients with acromegaly and 6 age-, sex- and weight-matched normal subjects. The levels of plasma glucose and serum insulin were determined during fasting and every 30 min up to 180 min after 75 g of oral glucose loading. In addition, plasma glucose, serum insulin and serum C-peptide were measured during euglycemic glucose clamp with insulin infusion of 40 mU/m2,min-1. The acromegalic patients had significantly higher mean levels of fasting plasma glucose (p less than 0.05) and insulin (p less than 0.01). After glucose loading for 3 h, the acromegalic patients also had a higher incremental area under the curve of plasma glucose (p less than 0.05) and serum insulin (p less than 0.05). However, no significant difference in the fasting molar ratio of C-peptide/IRI was noted between these two groups. During euglycemic clamp studies, the steady-state serum insulin levels were identical between the two groups. The glucose disposal rate was lower in acromegalics than in normal subjects (p less than 0.01). The results demonstrated that glucose intolerance, hyperinsulinemia and insulin resistance are present in acromegalic patients.     

The N6-methyladenosine mRNA methylase METTL14 promotes renal ischemic reperfusion injury via suppressing YAP1

Renal ischemia-reperfusion injury (IRI) is one of the most common causes of acute kidney injury (AKI), which is closely related to high morbidity and mortality. However, the pathogenesis underlying renal IRI is complex and not fully defined. N6-methyladenosine (m6A) was recently found to be an abundant modification in mammalian messenger RNAs. It is implicated in various biological processes, while the role of m6A in IRI is not illustrated. Here we show that the m6A-methylated RNA level and its methyltransferase METTL14 are elevated in human AKI renal tissues and IRI HK-2 cells. Moreover, METTL14 knockdown protects the kidney against IRI in vitro and in vivo. Mechanistically, we identified that YAP1 is a direct target of METTL14 in AKI progression. Inhibition of YAP1-TEAD signaling by peptide 17 abrogates the protective effect of METTL14 against IRI in vitro and in vivo. Taken together, these results reveal that the N6-methyladenosine mRNA methylase METTL14 promotes the renal IRI via suppressing YAP1. The discovery of the METTL14-YAP1 pathway provides an important new perspective for understanding AKI and is conducive to revealing new therapeutic strategies and targets.     

Investigations into the Stornatal Physiology of Upland Cotton: I. The Effects of Hour of Day, Solar Radiation, Temperature and Leaf Water-Content on Stomatal Behaviour

Stomatal behaviour was studied under field conditions usingan infiltration method with solutions of iso-butanol dilutedwith ethylene glycol. For mature leaves not suffering waterstrain, stomata in both epidermes commence opening at sunrise(6.30 a.m. local time) and have a maximum aperture between 10a.m. and 3 p.m.; subsequently a slow closure commences and thisis complete by 7 pjn. For leaves suffering marked water stress,i.e. with relative turgidity values falling below 85 per cent.,the period of maximum aperture is curtailed by a varying amountdependent upon the extent of water stress; closure occurs earlier,and no evidence has been found for a second opening later inthe day. For leaves not suffering water strain it is shown by means ofa multiple correlation analysis that stomatal aperture is significantlycorrelated with solar radiation, temperature, and hour of day.It is suggested that the hour-of-day effect may be a true diurnalrhythm controlled by factors within the leaf. The correlationsnoted above are not found for leaves with low values of relativeturgidity, since the effects of water strain tend to over-ridethose due to the other factors.     

The nutrition of the radish

Sand-culture experiments with the radish demonstrated that the optimum concentrations of nitrogen for root development were the highest employed, 32.96 and 65.92 p.p.m. Deficiency of nitrogen led to poor growth and to a characteristic outlining of the cotyledons in red, with red petioles. As with the carrot and turnip, a low concentration of available phosphorus, here 2.05-4.09 p.p.m., gave the best root growth; and a marketable radish was obtained with so little as 0.10 p.p.m., suggesting that the relatively large radish seed contains a considerable quantity of phosphorus. The highest concentration of potassium used, 22.44 p.p.m., yielded the largest roots, and a diminution in this amount led to loss of yield and eventually to serious scorch of the foliage. There is possibly some boron in the radish seed; for though absence of this from an otherwise satisfactory solution resulted in diminished yields, the foliage was normal in appearance, and the radish of eatable size; the radishes apparently lacked ability to swell.     

Downregulation of microRNA-23b protects against ischemia-reperfusion injury via p53 signaling pathway by upregulating MDM4 in rats

Total knee arthroplasty is a commonly performed safe procedure and typically executed in severe knee arthritis, but it also triggers ischemia-reperfusion injury (IRI). More recently, microRNAs (miRs) have been reported to play a contributory role in IRI through the key signaling pathway. Hence, the current study aimed to investigate the effect and specific mechanism of microRNA-23b (miR-23b), murine double minute 4 (MDM4), and the p53 signaling pathway in IRI rat models. First, the IRI model was established, and the expression pattern of miR-23b, MDM4, and the p53 signaling pathway-related genes was characterized in cartilaginous tissues. Then, miR-23b mimics or inhibitors were applied for the elevation or the depletion of the miR-23b expression and siRNA-MDM4 for the depletion of the MDM4 expression in the articular chondrocytes. By means of immunohistochemistry, quantitative real-time polymerase chain reaction, and Western blot analysis, IRI rats exhibited increased miR-23b expression, activated p53 signaling pathway, and decreased MDM4 expression. MDM4 was verified as a target gene of miR-23b through. Downregulated miR-23b increased the expression of MDM4, AKT, and Bcl-2, but decreased the expression of p53, p21, and Bax. In addition, a series of cell experiments demonstrated that downregulated miR-23b promoted articular chondrocyte proliferation and cell cycle entry, but inhibited articular chondrocyte apoptosis. The absence of the effects of miR-23b was observed after MDM4 knocked down. Our results indicate that silencing miR-23b could act to attenuate IRI and reduce the apoptosis of articular chondrocytes through inactivation of the p53 signaling pathway by upregulating MDM4, which provide basic therapeutic considerations for a novel target against IRI.     

Chronologic and quantitative modalities of luteinization and ovulation in the female rat exposed to FSH action at the beginning of 4-day cycles]

Female Wistar rats were injected with two successive doses of 150 mug FSH on dioestrus I (5 p. m.) and dioestrus II (9 a.m.) of 4-day cycles. Superovulation and formation of an increased number of corpora lutea with included oocytes occurred in these animals. Meprobamate or pentobarbitone injections at 11.30 a.m. et 1.30 p.m. respectively completely blocked ovulation and luteinization phenomena in FSH-treated females. Ovulation normally occurred in FSH-treated females injected with meprobamate at 5.30 p.m. It was concluded that no modification of timing of the 'critical period' resulted from FSH treatment.     

Hormones and Obesity: Changes in Insulin and Growth Hormone Secretion Following Surgically Induced Weight Loss

Ten obese patients were subjected to insulin tolerance tests (0.2 unit per kg. regular insulin intravenously) and/or treadmill exercise tolerance testing (2.6 m.p.h. at 11° angulation) before and after surgically induced weight reduction. Immunoreactive growth hormone (IRGH) responses returned to normal with weight reduction in all but one—a grossly obese woman studied relatively early in the postoperative period when still far from the ideal body weight. Five of these patients and two additional subjects had intravenous glucose tolerance tests (0.5 g. per kg.) before and after weight reduction. In all, there was a significant diminution in immunoreactive insulin (IRI) values, accompained by little or no change in the glucose disappearance rate (K_G) and a significant improvement in insulin effectiveness as indicated by the calculated “insulinogenic index”. It was concluded that the abnormalities in IRGH and IRI secretion, as well as the insulin resistance in obesity, are probably secondary and not of primary importance in the etiology of this disorder.     

MicroRNA‐153‐3p increases autophagy in sevoflurane‐preconditioned mice to protect against ischaemic/reperfusion injury after knee arthroplasty

The use of tourniquet during total knee arthroplasty (TKA) can result in ischaemia/reperfusion injury (IRI). Of interest, microRNAs (miRs) are reported to be involved in various kinds of IRI due to their ability in modulating autophagy. Therefore, the study aimed to investigate the effect of miR‐153‐3p on autophagy in IRI in vitro and in vivo under sevoflurane preconditioning. In the in vitro model, chondrocytes from naive mice were treated with 0% FBS alone or in combination with sevoflurane. Additionally, in vivo assays were conducted in mouse models with tourniquet‐induced IRI after TKA under or without sevoflurane preconditioning. The pathological observation in vivo validated that sevoflurane preconditioning protected the knee joint against IRI. Moreover, miR‐153‐3p expression was diminished in chondrocytes of the in vitro model and in cartilage tissue of the in vivo model, but its expression was appreciably up‐regulated in the presence of sevoflurane preconditioning. Mechanistic study showed that miR‐153‐3p disrupted the interaction between Bcl‐2 and Beclin1 by targeting Bcl‐2, thereby facilitating autophagy in chondrocytes under sevoflurane preconditioning. Furthermore, the experiments in human chondrocytes also verified the protective effects of miR‐153‐3p against IRI were realized through inhibiting Bcl‐2. Collectively, miR‐153‐3p overexpression blocks the interaction between Bcl‐2 and Beclin1 via down‐regulation of Bcl‐2 to promote autophagy of chondrocytes, thus protecting knee joint against IRI after TKA under sevoflurane preconditioning.     

Exotic sturgeons in the Vistula Lagoon in 2011, their occurrence,diet and parasites,with notes on the fishery background

The Siberian sturgeon Acipenser baerii and the sterlet Acipenser ruthenus were recorded for the first time in the Vistula Lagoon in 2011. Among 66 sturgeons collected between April and December 2011, the Siberian sturgeon was the most numerous species (77%); however, a significant seasonal variability was observed, with sterlet dominating in the catches in late autumn of the same year. The stomach contents of the two species differed widely: Siberian sturgeon (14.9–42.2 cm standard length, SL) fed on crustaceans (Cercopagis pengoi, Oithona sp., Neomysis integer) (10.7% IRI), larvae and pupas of insects (Chaoborus sp., Chironomus sp., Polypedilum sp., Procladius sp., Culex sp.) (88.9% IRI) and fishes (Neogobius melanostomus, Osmerus eperlanus) (0.5% IRI), whereas sterlet (24.0–34.4 cm SL) consumed crustaceans (N. integer) (64.3% IRI), larvae of insects (Chironomus sp., Polypedilum sp.) (20.3% IRI) and fish (N. melanostomus) (15.4% IRI). Single Siberian sturgeon (4.3%) were found to harbour the parasitic nematode (Raphidascaris acus).     

Insulin and C-peptide secretion in non-obese patients with polycystic ovarian disease

Plasma glucose, immunoreactive insulin (IRI) and C-peptide responses during an oral glucose tolerance test (oGTT) were assessed in 11 non-obese patients with polycystic ovarian disease (PCOD) and 11 reference subjects matched for age, height and weight. Also, 6 patients with PCOD and 6 normal women were subjected to intravenous glucose tolerance testing (ivGTT) On oGTT, all subjects exhibited normal glucose tolerance; however, PCOD patients had significantly higher mean plasma glucose levels at 30, 60, 90 and 120 min and higher mean incremental glucose areas. In addition the patients with polycystic ovaries showed higher mean basal IRI and C-peptide levels, higher mean glucose stimulated IRI and C-peptide levels and higher mean incremental IRI and C-peptide values. The molar ratios of C-peptide/IRI were significantly lower in the PCOD group at all time intervals after glucose stimulation when compared to the normal women. During ivGTT, there were significantly higher mean glucose levels at 5, 40, 50 and 60 min in the PCOD group when compared to the reference group. The IRI response to intravenous glucose in the PCOD women was similar to the reference group. The findings on oGTT suggest that non-obese patients with PCOD have increased pancreatic IRI secretion as well as impaired hepatic extraction of the hormone.     

A case of autoimmune insulin antibody syndrome associated with polymyositis, empty sella and apparent high urinary output of immunoreactive insulin.

Patients with autoimmune insulin antibody are characterized by hypoglycemic attacks and antibodies to insulin in serum without prior insulin administration. In the present report, a patient with hypoglycemia due to autoimmune insulin antibody associated with primary empty sella syndrome and polymyositis appeared to have high urinary immunoreactive insulin (IRI) in the face of normal urinary C peptide. Consequently, the urinary IRI/C peptide ratio was apparently high. The amelioration of hypoglycemic attacks and polymyositis by prednisolone treatment was accompanied by the disappearance of the antibodies and complete normalization of the urinary IRI and IRI/C peptide ratio. No comparable rise in the urinary IRI and IRI/C peptide ratio was observed in the patients with other disorders studied. Glucose clamp and glucose tolerance study showed decreased sensitivity to exogenous or newly secreted insulin, prolonged half disappearance time of serum insulin, and normal disappearance of blood glucose. These results were consistent with the idea that autoantibodies buffered the effect of exogenous or newly secreted insulin and maintained a relatively constant level of serum free insulin which was not high enough when a large amount of glucose was loaded, but was too high after prolonged fasting, which eventually caused hypoglycemic attacks.