Erythrocytes and glucose homeostasis in rats

The capacity of erythrocytes to modify their glycogen stores to compensate for changes in glucose concentration in plasma was studied. Experiments in vitro and in vivo demonstrated that erythrocytes absorbed and incorporated glucose into their glycogen stores when glucose concentration in the medium was high and liberated it when the concentration was low. Epinephrine administration inhibited glucose absorption by erythrocytes, and in its presence, erythrocytes liberated glucose from their glycogen stores, being unable to compensate for this rise in glucose concentration in plasma. Similar results were obtained when endogenous secretion of epinephrine was enhanced by carotid sinus-chemoreceptor stimulation. Insulin had no effect on the capacity of erythrocytes to absorb glucose. These data suggest a role for erythrocytes in the transport of glucose to different regions in the organism's circulation and in the regulation of glucose concentration in plasma.     

Quantifying fluctuation in glucose levels to identify early changes in glucose homeostasis in cystic fibrosis

Background

Cystic fibrosis related diabetes (CFRD) is associated with increased morbidity in CF. Variability in physiological systems is associated with dysfunctional homeostasis. We examined whether fluctuation in glucose is a marker of CFRD or “pre-diabetes”.

Effects of glucose homeostasis on protein metabolism in patients with advanced chronic kidney disease.

Insulin deficiency is known to be associated with a state of increased muscle protein breakdown; this process is mediated by the ubiquitin-proteasome pathway. Convincing in vitro data are further supported by extensive studies in humans with insulin deprivation and are further substantiated by reversal of muscle protein breakdown with insulin treatment. In patients with end-stage renal disease (ESRD) and diabetes mellitus (DM), muscle protein breakdown is enhanced in both acute and chronic conditions. Recent data also point to the potential protein catabolic effects of insulin resistance combined with insulin deficiency. Because ESRD is associated with a state of insulin resistance, uremic muscle wasting may also be mediated by this pathway.     

慢性胰腺炎并发门静脉高压症

目的 探讨慢性胰腺炎并发门静脉高压症的诊断和治疗.方法 回顾性分析该院1990年3月至2005年10月收治的慢性胰腺炎所致的胰源性门静脉高压症21例,其中左侧门静脉高压症16例,肝前型门静脉高压症5例.其诊断依据主要依靠多普勒超声、CT和MR等影像学检查和上消化道内镜检查,肝前性门静脉高压症有时须行MRA或肠系膜上动脉血管造影.治疗左侧门静脉高压症可行脾切除术,肝前型门静脉高压症有出血史者可行肠系膜上静脉、下腔静脉分流术,必要时加行脾切除术.结果 21例均获随访,随访时间1～5年,病人恢复良好,脾亢纠正,15例行上消化道内镜复查,曲张静脉消失或仅有轻度曲张,10例有出血史者未再发生出血.结论 注意慢性胰腺炎所致的胰源性左侧门静脉高压症的诊断治疗的同时应注意SMV-PV阻塞所致的肝前性门静脉高压症的诊治.     

Morphometric study on islet of Langerhans in relation to glucose tolerance in chronic obstructive pancreatitis due to pancreatoduodenal cancer]

Twenty one specimens of the pancreas in the patients who underwent pancreatoduodenectomy or total pancreatectomy for pancreatoduodenal cancer were divided into 4 groups according to the extent of fibrosis (Grade 0-Grade III). Islet cells of serial sections were stained immunohistochemically with calculation of the proportion of B-cells, A-cells, D-cells and PP-cells in the islets of Langerhans. In the pancreatic tissue with the most severe fibrosis (Grade III), B-cell ratio was significantly decreased (p less than 0.01), whereas A-cell ratio was significantly increased (p less than 0.01). Based on the data of oral glucose tolerance test (OGTT) and insulin response test, some indices were calculated (delta IRI/delta BS, sigma IRI/sigma BS, sigma delta IRI/sigma delta BS). In Grade III, sigma delta IRI/sigma delta BS was significantly decreased. A significant positive correlation was observed between B-cell ratio and both delta IRI/delta BS or sigma delta IRI/sigma delta BS, whereas a significant negative correlation was seen between A-cell ratio and sigma delta IRI/sigma delta BS. The present study first demonstrates the significant correlation between the endocrine secretory function of the islets and quantitative changes of the endocrine cells of islets in chronic obstructive pancreatitis due to pancreatoduodenal cancer. The present data strongly suggest that it is possible to estimate the degree of fibrosis and quantitative changes of the islet cells in the patients with pancreatoduodenal cancer by means of calculating the above mentioned indices, especially sigma delta IRI/sigma delta BS.     

Effects of intracisternal glucose or insulin injections on glucose homeostasis in cat

The injection of glucose (100 mg) into the cisterna magna of intact anesthetized cats elicited immediate glycosuria and natriuresis without significant changes in blood glucose concentration. Immunoreactive insulin (IRI) increased 140% in plasma, and Na+ concentration decreased in cerebrospinal fluid (CSF). After kidney denervation there was a significant decrease in glucose and Na+ concentrations in urine. Control injections with mannitol did not elicit changes in the studied parameters. Abdominal vagotomy abolished the rise in IRI levels and the decrease in Na+ concentration in CSF. Vagotomy or adrenalectomy also attenuated the glycosuria and the rise in urine Na+ concentration. The intracisternal injection of insulin (0.5 U/kg) caused first, a decrease in glucose concentration in CSF and afterwards a longer latency in plasma. Again, these responses were significantly attenuated when insulin was administered in vagotomized cats. These experiments indicate that the nervous system, through the vagi, adrenal glands, and kidneys, plays an important role in glucose homeostasis after increasing glucose or insulin levels in the CSF above physiologic concentrations. The results obtained with a denervated kidney confirm the participation of nervous system in the effector mechanism that brings the sugar and Na+ into the urine. Evidence is presented for an interrelationship between glucose and Na+ concentrations in blood, urine, and CSF.     

Abnormal glucose tolerance testing after gastric bypass

BackgroundSymptoms secondary to dumping have been suggested to help patients refrain from simple carbohydrate ingestion after Roux-en-Y gastric bypass (RYGB). During follow-up examinations, we noted many patients with weight regain complaining of fatigue shortly after eating. Thus, we decided to study the glucose tolerance test (GTT) results in a cohort of post-RYGB patients.MethodsA total of 63 RYGB patients, >6 months postoperatively, were studied with a GTT and measurement of insulin levels. The mean age was 48.5 ± 10.8 years, mean preoperative body mass index was 49.0 ± 6.5 kg/m², mean percentage of excess body mass index lost was 64.5% ± 29.0%, mean weight regain at follow-up was 11.6 ± 12.4 lb, and mean follow-up period was 47.9 months.ResultsOf the 63 patients, 49 had abnormal GTT results. Of the 63 patients, 6 were diabetic; however, only 1 of these patients had an elevated fasting glucose level. All 6 patients were diabetic preoperatively. Of the 63 patients, 43 had evidence of reactive hypoglycemia at 1–2 hours after the glucose load. Of these patients, 22 had a maximum/minimum glucose ratio >3:1, including 7 with a ratio >4:1.ConclusionThe results of the present study have demonstrated that an abnormal GTT result is a common finding after RYGB. Reactive hypoglycemia was found in 43 of 63 patients, with insulin values that do not support nesidioblastosis. It is our hypothesis, that rather than preventing simple carbohydrate ingestion, the induced hypoglycemia that occurs might contribute to weight regain and maladaptive eating in certain post-RYGB patients.     

Huge arteriovenous malformation due to chronic infection

Acquired pulmonary arteriovenous malformations (AVMs) related to chronic infections are extremely rare. We report a 32-year-old male patient having a huge pulmonary AVMs being fed with multi-systemic vascular divisions weeded in ascending aorta due to chronic infection. The AVMs were managed by combined intra-arterial embolization and surgical resection.     

Multiorgan failure due to chronic granulomatous disease

A 21-year-old male patient developed an acute septic clinical picture with intra-abdominal abscesses and multiorgan failure. The underlying disease was chronic granulomatous disease, an inherited disorder of granulocyte function caused by failure of intracellular superoxide production. In spite of surgical procedures and a calculated antibiotic and antimycotic therapy, the patient died within a few days from septic shock. This case report describes the typical problems of patients with a congenital immunodeficiency who grow out of the care of highly specialised pediatric-immunological departments.     

Impaired glucose homeostasis in adult rats from hyperglycemic mothers

The purpose of our study was to investigate whether nondiabetic gestational hyperglycemia during fetal life could have additional effects on glucose homeostasis and insulin secretion in the adult rat. Hyperglycemia without the main other metabolic disorders and vascular injuries associated with diabetes was produced in unrestrained pregnant rats by continuous glucose infusion during the last week of pregnancy. Control rats were infused with distilled water. Compared with controls, the newborns from hyperglycemic rats were hyperglycemic and hyperinsulinemic. When studied longitudinally up to 3 mo, they showed slightly but significantly increased basal plasma glucose levels and normal basal insulin concentrations compared with controls. Glucose tolerance and insulin secretion in response to a glucose load (0.5 mg/kg, i.v.) were altered: Plasma glucose values were more increased at 5 min and remained higher 90 min after glucose injection; incremental plasma insulin values and the insulinogenic indexes (delta IRI/delta G) were always lower in rats from hyperglycemic mothers than in controls. These alterations were more and more marked with advancing age (1-3 mo). These data show that gestational hyperglycemia may lead to persistent impairment of glucose homeostasis and insulin secretion in the adult rat.     

Loss of resistin improves glucose homeostasis in leptin deficiency

Resistin levels are increased in obesity, and hyperresistinemia impairs glucose homeostasis in rodents. Here, we have determined the role of resistin in ob/ob mice that are obese and insulin resistant because of genetic deficiency of leptin. Loss of resistin increased obesity in ob/ob mice by further lowering the metabolic rate without affecting food intake. Nevertheless, resistin deficiency improved glucose tolerance and insulin sensitivity in these severely obese mice, largely by enhancing insulin-mediated glucose disposal in muscle and adipose tissue. In contrast, in C57BL/6J mice with diet-induced obesity but wild-type leptin alleles, resistin deficiency reduced hepatic glucose production and increased peripheral glucose uptake. Resistin deficiency enhanced Akt phosphorylation in muscle and liver and decreased suppressor of cytokine signaling-3 level in muscle, and these changes were reversed by resistin replacement. Together, these results provide strong support for an important role of resistin in insulin resistance and diabetes associated with genetic or diet-induced obesity.     

Conundrum of vitamin D on glucose and fuel homeostasis

As an endocrine hormone, vitamin D plays an important role in bone health and calcium homeostasis. Over the past two decades, the non-calcemic effects of vitamin D were extensively examined. Although the effect of vitamin D on beta cell function were known for some time, the effect of vitamin D on glucose and fuel homeostasis has attracted new interest among researchers. Yet, to date,studies remain inconclusive and controversial, in part, due to a lack of understanding of the threshold effects of vitamin D. In this review, a critical examination of interventional trials of vitamin D in prevention of diabetes is provided. Like use of vitamin D for bone loss, the benefits of vitamin D supplementation in diabetes prevention were observed in vitamin D-deficient subjects with serum 25-hydroxyvitamin D 50 nmol/L(20 ng/mL). The beneficial effect from vitamin D supplementation was not apparent in subjects with serum 25-hydroxyvitamin D 75 nmol/L(30 ng/mL). Furthermore, no benefit was noted in subjects that achieved serum 25-hydroxyvitamin D 100 nmol/L(40 ng/mL).Further studies are required to confirm these observations.     

Spontaneous urinary extravasation due to chronic ureteral obstruction

Spontaneous nontraumatic perirenal extravasation of urine is an unusual phenomenon, and the majority of the reported case were caused by acute obstruction with passage of a ureteric calculus. Extravasation due to obstruction of more gradual onset occurs less frequently. We report four cases, three caused by tumor obstruction of the ureter, and one thought to be obstructed by the stricture due to ureteral inflammation. We discuss the diagnosis and treatment of spontaneous urinary extravasation, especially due to chronic ureteral obstruction.     

Continuous positive airway pressure to improve insulin resistance and glucose homeostasis in sleep apnea

Obstructive sleep apnea syndrome(OSAS)is a relatively common disorder in the adult population.It is associated with alterations in glucose metabolism and increases the risk for diabetes mellitus.Continuous positive airway pressure(CPAP)is the treatment of choice for OSAS.It may also have a favorable effect on insulin resistance and glucose metabolism,although relevant data is conflicting.Additional research is still needed to fully establish the effect of CPAP on glucose homeostasis.It should ascertain which patients may benefit most and how long treatment takes to induce favorable changes.Finally,patient compliance is being appreciated as a major factor influencing therapeutic outcomes,and this needs to be further examined.