Multimodal imaging of the role of hyperglycemia following experimental subarachnoid hemorrhage

Hyperglycemia has been linked to worsening outcomes after subarachnoid hemorrhage (SAH). Nevertheless, the mechanisms involved in the pathogenesis of SAH have been scarcely evaluated so far. The role of hyperglycemia was assessed in an experimental model of SAH by T2 weighted, dynamic contrast-enhanced magnetic resonance imaging (T2W and DCE-MRI), [18F]BR-351 PET imaging and immunohistochemistry. Measures included the volume of bleeding, the extent of cerebral infarction and brain edema, blood brain barrier disruption (BBBd), neutrophil infiltration and matrix metalloprotease (MMP) activation. The neurofunctional outcome, neurodegeneration and myelinization were also investigated. The induction of hyperglycemia increased mortality, the size of the ischemic lesion, brain edema, neurodegeneration and worsened neurological outcome during the first 3 days after SAH in rats. In addition, these results show for the first time the exacerbating effect of hyperglycemia on in vivo MMP activation, Intercellular Adhesion Molecule 1 (ICAM-1) expression and neutrophil infiltration together with increased BBBd, bleeding volume and fibrinogen accumulation at days 1 and 3 after SAH. Notably, these data provide valuable insight into the detrimental effect of hyperglycemia on early BBB damage mediated by neutrophil infiltration and MMP activation that could explain the worse prognosis in SAH.

Intravoxel incoherent motion diffusion-weighted imaging of pancreas: Probing evidence of β-cell dysfunction in asymptomatic adults with hyperglycemia in vivo

PURPOSE

Early evaluation of β-cell dysfunction of hyperglycemic patients in asymptomatic adults would be valuable for timely prevention of the diabetes. This study aimed to evaluate functional changes in the pancreas using intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) and determine whether it could be used as a non-invasive method of assessing β-cell dysfunction.

METHODS

This prospective cohort study was conducted from August 2022 to November 2022 in Jinan University Affiliated Guangdong Second General Hospital. Three groups were enrolled and underwent IVIM-DWI: confirmed patients with type 2 diabetes (T2DM); hyperglycemic patients in asymptomatic adults; and the volunteers with normal glucose tolerance (NGT). Imaging parameters were obtained: apparent diffusion coefficient (ADC), the true diffusion coefficient (Dt), the pseudo-diffusion coefficient (Dp), and the perfusion fraction (f). The β-cell function indexes were calculated from blood examinations: composite insulin sensitivity index (ISI), 60-min insulinogenic index (IGI60), and the disposition index (DI). We compared imaging parameters among three groups, calculated the diagnostic performance of them for differentiating different groups, and the reproducibility of them was evaluated using intraclass correlation coefficient (ICC).

RESULTS

The imaging parameters except f gradually decreased among the groups with significant differences for ADC (p < 0.0001), Dt (p < 0.0001), and Dp (p = 0.013). Dt demonstrated the best diagnostic performance for differentiating asymptomatic patients from NGT (Area Under Curve [AUC] = 0.815, p < 0.0001). IVIM-DWI parameters correlated with composite ISI and DI, of which, Dt has the highest correlation with DI (Pearson correlation coefficient [r] = 0.546, p < 0.0001). The ICC of IVIM-DWI parameters was very good, Dt was highest (Interobserver ICC = 0.938, 95% Confidence Interval [CI], 0.899-0.963; Intraobserver ICC = 0.941, 95% CI, 0.904-0.965).

CONCLUSION

IVIM-DWI is a non-invasive quantitative method that can identify β-cell dysfunction in the pancreas.

Acute hyperglycemia compromises the responses of choroidal vessels using swept-source optical coherence tomography during dark and light adaptations

PURPOSE

To clarify the effects of acute hyperglycemia on the responses of choroidal structural components and vascularity index during light modulation in healthy participants using techniques including image binarization and artificial intelligence (AI) segmentation based on swept-source optical coherence tomography (SS-OCT).

METHODS

Twenty-four eyes of 24 healthy participants were imaged at different stages after ambient light, 40 min of dark adaptation, and 5 min of light adaptation in two imaging sessions: control and after receiving 75 g of oral glucose solution. The choroidal structural parameters, including luminal volume (LV), stromal volume (SV), total choroidal volume (TCV), and choroidal vascularity index (CVI) within a 6 mm area were determined using a custom algorithm based on image binarization and AI segmentation of SS-OCT. These measurements were compared among the conditions after adjusting for axial length, age to identify the differences.

RESULTS

In the dark, CVI decreased (-0.36 ± 0.09%) significantly in acute hyperglycemia compared to the control condition. During the transition to ambient light, there was an increasing trend in the choroidal parameters compared with the control experiment. However, only TCV (0.38 ± 0.17 mm³) and LV (0.27 ± 0.10 mm³) showed a significant increase at the time point of 5 min after ambient light.

CONCLUSION

Analysis of choroidal structural parameters and CVI based on SS-OCT images is a potentially powerful method to objectively reflect subtle changes in neurovascular coupling between the choroid and photoreceptor during dark adaptation.

Sex-related differences in whole brain volumes at age 70 in association with hyperglycemia during adult life

Longitudinal studies of the relationship between hyperglycemia and brain health are rare and there is limited information on sex differences in associations. We investigated whether glycosylated hemoglobin (HbA1c) measured at ages of 53, 60-64 and 69 years, and cumulative glycemic index (CGI), a measure of cumulative glycemic burden, were associated with metrics of brain health in later life. Participants were from Insight 46, a substudy of the Medical Research Council National Survey of Health and Development (NSHD) who undertook volumetric MRI, florbetapir amyloid-PET imaging and cognitive assessments at ages of 69-71. Analyses were performed using linear and logistic regression as appropriate, with adjustment for potential confounders. We observed a sex interaction between HbA1c and whole brain volume (WBV) at all 3 time points. Following stratification of our sample, we observed that HbA1c at all ages, and CGI were positively associated with lower WBV exclusively in females. HbA1c (or CGI) was not associated with amyloid status, white matter hyperintensities (WMHs), hippocampal volumes (HV) or cognitive outcomes in either sex. Higher HbA1c in adulthood is associated with smaller WBV at 69-71 years in females but not in males. This suggests that there may be preferential target organ damage in the brain for females with hyperglycemia.

Acute hyperglycaemia leads to altered frontal lobe brain activity and reduced working memory in type 2 diabetes

How acute hyperglycaemia affects memory functions and functional brain responses in individuals with and without type 2 diabetes is unclear. Our aim was to study the association between acute hyperglycaemia and working, semantic, and episodic memory in participants with type 2 diabetes compared to a sex- and age-matched control group. We also assessed the effect of hyperglycaemia on working memory–related brain activity. A total of 36 participants with type 2 diabetes and 34 controls (mean age, 66 years) underwent hyperglycaemic clamp or placebo clamp in a blinded and randomised order. Working, episodic, and semantic memory were tested. Overall, the control group had higher working memory (mean z-score 33.15 ± 0.45) than the group with type 2 diabetes (mean z-score 31.8 ± 0.44, p = 0.042) considering both the placebo and hyperglycaemic clamps. Acute hyperglycaemia did not influence episodic, semantic, or working memory performance in either group. Twenty-two of the participants (10 cases, 12 controls, mean age 69 years) were randomly invited to undergo the same clamp procedures to challenge working memory, using 1-, 2-, and 3-back, while monitoring brain activity by blood oxygen level–dependent functional magnetic resonance imaging (fMRI). The participants with type 2 diabetes had reduced working memory during the 1- and 2-back tests. fMRI during placebo clamp revealed increased BOLD signal in the left lateral frontal cortex and the anterior cingulate cortex as a function of working memory load in both groups (3>2>1). During hyperglycaemia, controls showed a similar load-dependent fMRI response, whereas the type 2 diabetes group showed decreased BOLD response from 2- to 3-back. These results suggest that impaired glucose metabolism in the brain affects working memory, possibly by reducing activity in important frontal brain areas in persons with type 2 diabetes.

Abnormalities in evoked potentials associated with abnormal glycemia and brain injury in neonatal hypoxic-ischemic encephalopathy

OBJECTIVE

To investigate how functional integrity of ascending sensory pathways measured by visual and somatosensory evoked potentials (VEP & SEP) is associated with abnormal glycemia and brain injury in newborns treated with hypothermia for hypoxic-ischemic encephalopathy (HIE).

METHODS

Fifty-four neonates ≥ 36 weeks gestational age with HIE underwent glucose testing, VEPs, SEPs, and magnetic resonance imaging (MRI) the first week of life. Minimum and maximum glucose values recorded prior to evoked potential (EP) testing were compared with VEP and SEP measures using generalized estimating equations. Relationships between VEP and SEP measures and brain injury on MRI were assessed.

RESULTS

Maximum glucose is associated with decreased P200 amplitude, and increased odds that N300 peak will be delayed/absent. Minimum glucose is associated with decreased P22 amplitude. Presence of P200 and N300 peaks is associated with decreased odds of brain injury in the visual processing pathway, with delayed/absent N300 peak associated with increased odds of brain injury in posterior white matter.

CONCLUSIONS

Deviations from normoglycemia are associated with abnormal EPs, and abnormal VEPs are associated with brain injury on MRI in cooled neonates with HIE.

SIGNIFICANCE

Glucose is a modifiable risk factor associated with atypical brain function in neonates with HIE despite hypothermia treatment.

High-glucose mixed-nutrient meal ingestion impairs skeletal muscle microvascular blood flow in healthy young men

Oral glucose ingestion leads to impaired muscle microvascular blood flow (MBF), which may contribute to acute hyperglycemia-induced insulin resistance. We investigated whether incorporating lipids and protein into a high-glucose load would prevent postprandial MBF dysfunction. Ten healthy young men (age, 27 yr [24, 30], mean with lower and upper bounds of the 95% confidence interval; height, 180 cm [174, 185]; weight, 77 kg [70, 84]) ingested a high-glucose (1.1 g/kg glucose) mixed-nutrient meal (10 kcal/kg; 45% carbohydrate, 20% protein, and 35% fat) in the morning after an overnight fast. Femoral arterial blood flow was measured via Doppler ultrasound, and thigh MBF was measured via contrast-enhanced ultrasound, before meal ingestion and 1 h and 2 h postprandially. Blood glucose and plasma insulin were measured at baseline and every 15 min throughout the 2-h postprandial period. Compared with baseline, thigh muscle microvascular blood volume, velocity, and flow were significantly impaired at 60 min postprandial (-25%, -27%, and -46%, respectively; all P < 0.05) and to a greater extent at 120 min postprandial (-37%, -46%, and -64%; all P < 0.01). Heart rate and femoral arterial diameter, blood velocity, and blood flow were significantly increased at 60 min and 120 min postprandial (all P < 0.05). Higher blood glucose area under the curve was correlated with greater MBF dysfunction (R² = 0.742; P < 0.001). Ingestion of a high-glucose mixed-nutrient meal impairs MBF in healthy individuals for up to 2 h postprandial.

Prediction of hypertension, hyperglycemia and dyslipidemia from retinal fundus photographs via deep learning: A cross-sectional study of chronic diseases in central China

Retinal fundus photography provides a non-invasive approach for identifying early microcirculatory alterations of chronic diseases prior to the onset of overt clinical complications. Here, we developed neural network models to predict hypertension, hyperglycemia, dyslipidemia, and a range of risk factors from retinal fundus images obtained from a cross-sectional study of chronic diseases in rural areas of Xinxiang County, Henan, in central China. 1222 high-quality retinal images and over 50 measurements of anthropometry and biochemical parameters were generated from 625 subjects. The models in this study achieved an area under the ROC curve (AUC) of 0.880 in predicting hyperglycemia, of 0.766 in predicting hypertension, and of 0.703 in predicting dyslipidemia. In addition, these models can predict with AUC>0.7 several blood test erythrocyte parameters, including hematocrit (HCT), mean corpuscular hemoglobin concentration (MCHC), and a cluster of cardiovascular disease (CVD) risk factors. Taken together, deep learning approaches are feasible for predicting hypertension, dyslipidemia, diabetes, and risks of other chronic diseases.

Association between Admission Hyperglycemia and Culprit Lesion Characteristics in Nondiabetic Patients with Acute Myocardial Infarction: An Intravascular Optical Coherence Tomography Study

BACKGROUND

Hyperglycemia is frequently observed in acute myocardial infarction (AMI). Diabetes mellitus (DM) patients and non-DM patients have different culprit lesion phenotypes and few data are available on non-DM patients with admission hyperglycemia. Therefore, we aimed to investigate the association between admission hyperglycemia and culprit lesion characteristics using optical coherence tomography (OCT) in AMI patients.

METHODS AND RESULTS

We consecutively enrolled 434 patients with AMI, and 277 patients were included in analysis: 65.7% (n = 182) non-DM patients and 34.3% (n = 95) DM patients. We measured acute blood glucose (ABG) and hemoglobin A_1c to calculate the acute-to-chronic glycemic ratio (A/C). Then, we grouped non-DM patients into tertiles of A/C. OCT-based culprit lesion characteristics were compared across A/C tertiles in non-DM patients and between DM and non-DM patients. Non-DM patients had fewer lipid-rich plaques (52.7% versus 68.4%, p = 0.012) and thin-cap fibroatheroma (TCFA) (19.8% versus 34.7%, p = 0.006) than DM patients but similar prevalence of plaque rupture (47.3% versus 56.8%, p = 0.130). Non-DM patients with the highest A/C tertile had the highest prevalence of plaque rupture (p _for trend = 0.002), lipid-rich plaque (p _for trend = 0.001), and TCFA (p _for trend = 0.003). A/C > 1.22 but not ABG > 140 mg/dl predicted a high prevalence of plaque rupture, lipid-rich plaque, and TCFA in non-DM patients.

CONCLUSIONS

In AMI patients without DM, admission hyperglycemia is associated with vulnerable culprit lesion characteristics, and A/C is a better predictor for vulnerable culprit plaque characteristics than ABG. These results call for a tailored evaluation and management of glucose metabolism in nondiabetic AMI patients. This trial is registered with NCT03593928.

Multiparameter wide-field integrated optical imaging system-based spatially modulated illumination and laser speckles in model of tissue injuries

In this report, an integrated optical platform based on spatial illumination together with laser speckle contrast technique was utilized to measure multiple parameters in live tissue including absorption, scattering, saturation, composition, metabolism, and blood flow. Measurements in three models of tissue injury including drug toxicity, artery occlusion, and acute hyperglycemia were used to test the efficacy of this system. With this hybrid apparatus, a series of structured light patterns at low and high spatial frequencies are projected onto the tissue surface and diffuse reflected light is captured by a CCD camera. A six position filter wheel, equipped with four bandpass filters centered at wavelengths of 650, 690, 800 and 880 nm is placed in front of the camera. Then, light patterns are blocked and a laser source at 650 nm illuminates the tissue while the diffusely reflected light is captured by the camera through the two remaining open holes in the wheel. In this manner, near-infrared (NIR) and laser speckle images are captured and stored together in the computer for off-line processing to reconstruct the tissue's properties. Spatial patterns are used to differentiate the effects of tissue scattering from those of absorption, allowing accurate quantification of tissue hemodynamics and morphology, while a coherent light source is used to study blood flow changes, a feature which cannot be measured with the NIR structured light. This combined configuration utilizes the strengths of each system in a complementary way, thus collecting a larger range of sample properties. In addition, once the flow and hemodynamics are measured, tissue oxygen metabolism can be calculated, a property which cannot be measured independently. Therefore, this merged platform can be considered a multiparameter wide-field imaging and spectroscopy modality. Overall, experiments demonstrate the capability of this spatially coregistered imaging setup to provide complementary, useful information of various tissue metrics in a simple and noncontact manner, making it attractive for use in a variety of biomedical applications.

Decreased cerebral blood flow and hemodynamic parameters during acute hyperglycemia in mice model observed by dual-wavelength speckle imaging

In this study, we use dual-wavelength optical imaging-based laser speckle technique to assess cerebral blood flow and metabolic parameters in a mouse model of acute hyperglycemia (high blood glucose). The effect of acute glucose levels on physiological processes has been extensively described in multiple organ systems such as retina, kidney, and others. We postulated that hyperglycemia also alters brain function, which in turn can be monitored optically using dual-wavelength laser speckle imaging (DW-LSI) platform. DW-LSI is a wide-field, noncontact optical imaging modality that integrates the principles of laser flowmetry and oximetry to obtain macroscopic information such as hemoglobin concentration and blood flow. A total of eight mice (C57/BL6) were used, randomized into two groups of normoglycemia (control, n = 3) and hyperglycemia (n = 5). Hyperglycemia was induced by intraperitoneal injection of a commonly used anesthetic drug combining ketamine and xylazine (KX combo). We found that this KX combo increases blood glucose (BG) levels from 150 to 350 mg/dL, approximately, when measured 18 minutes post-administration. BG continues to increase throughout the test period, with BG reaching an average of 463 ± 20.34 mg/dL within 60 minutes. BG levels were measured every 10 minutes from tail blood using commercially available glucometer. Experimental results demonstrated reductions in cerebral blood flow (CBF) by 55%, tissue oxygen saturation (SO₂ ) by 15%, and cerebral metabolic rate of oxygen (CMRO₂ ) by 75% following acute hyperglycemia. The observed decrease in these parameters was consistent with results reported in the literature, measured by a variety of experimental techniques. Measurements with laser Doppler flowmetry (LDF) were also performed which confirmed a reduction in CBF following acute hyperglycemia. In summary, our findings indicate that acute hyperglycemia modified brain hemodynamic response and induced significant changes in blood flow and metabolism. As far as we are aware, the implementation of the DW-LSI to monitor brain hemodynamic and metabolic response to acute hyperglycemia in intact mouse brain has not been previously reported.

[Hemichorea/hemiballism a rare complication of hyperglycemia]

We present a case of hemichorea/hemiballism, a rare complication of hyperglycemia. Diagnosis is made clinically by signs of unilateral involuntary movements of the extremities combined with typical neuroradiological findings in the basal ganglia. Guidelines for treatment of the condition are lacking but in many cases correction for hyperglycemia is sufficient for full symptom relief. In other cases, symptomatic treatment with haloperidol and tetrabenazine can be used.

Effects of plasma glucose levels on regional cerebral 18F-fluorodeoxyglucose uptake: Implications for dementia evaluation with brain PET imaging

Purpose:

Hyperglycemia affects FDG uptake in the brain, potentially emulating Alzheimer’s disease in normal individuals. This study investigates global and regional cerebral FDG uptake as a function of plasma glucose in a cohort of patients.

Methods:

120 consecutive male patients with FDG PET/CT for initial oncologic staging (July-Dee 2015) were reviewed. Patients with dementia, cerebrovascular accident, structural brain lesion, prior oncology treatment or high metabolic tumor burden (recently shown affecting brain FDG uptake) were excluded. 53 (24 nondiabetic) eligible patients (age 65.7 ± 2.8 mean ± SE) were analyzed with parametric computer software, MIMneuro™. Regional Z-scores were evaluated as a function of plasma glucose and age using multi variable linear mixed effects models with false discovery analysis adjusting for multiple comparisons. If the regression slope was significantly (p < 0.05) different than zero, hyperglycemia effect was present.

Results:

There was a negative inverse relationship (p < 0.001) between global brain FDG uptake and hyperglycemia. No regional hyperglycemia effect on uptake were present when subjects were normalized using pons or cerebellum. However, regional hyperglycemia effects were seen (p < 0.047–0.001) when normalizing by the whole brain. No obvious pattern was seen in the regions affected. Age had a significant effect using whole brain normalization (p < 0.04–0.01).

Conclusions:

Cortical variation in FDG uptake were identified when subjects were hyperglycemic. However, these variations didn’t fit a particular pattern of dementia and the severity of the affect is not likely to alter clinical interpretation.

In Vivo Corneal Confocal Microscopy Detects Improvement of Corneal Nerve Parameters following Glycemic Control in Patients with Type 2 Diabetes

AIM

This study aimed to investigate whether in vivo corneal confocal microscopy (CCM) can detect the improvement of corneal nerve parameters following glycemic control in patients with type 2 diabetes in natural history.

METHODS

Thirty-two patients with diabetes complicated by DPN and 12 age-matched control subjects underwent detailed clinical examination and were assessed per the Toronto Clinical Scoring Scale for DPN, nerve conduction studies, and IVCCM at baseline and after approximately one year from the first visit.

RESULTS

At follow-up, 16 diabetic patients had improved glycemic control (group A, HbA1c < 7.0%, 7.78 ± 1.62% versus 6.52 ± 0.59%, P = 0.005), while the remainder continued to have elevated HbA1c levels (group B, HbA1c ≥ 7.0%, 8.55 ± 1.57% versus 8.79 ± 1.05%, P = 0.527). For patients in group A, corneal nerve fiber density (CNFD) (18.55 ± 5.25 n/mm² versus 21.78 ± 6.13 n/mm², P = 0.005) and corneal nerve fiber length (CNFL) (11.62 ± 2.89 mm/mm² versus 13.04 ± 2.44 mm/mm², P = 0.029) increased significantly compared to baseline. For patients in group B, sural sensory nerve conduction velocity (47.93 ± 7.20 m/s versus 44.67 ± 6.43 m/s, P = 0.024), CNFD (17.19 ± 5.31 n/mm² versus 15.67 ± 4.16 n/mm², P = 0.001), corneal nerve branch density (19.33 ± 12.82 n/mm² versus 14.23 ± 6.56 n/mm², P = 0.033), and CNFL (11.16 ± 2.57 mm/mm² versus 9.90 ± 1.75 mm/mm², P = 0.011) decreased significantly.

CONCLUSIONS

The results of this study suggest that morphological repair of corneal nerve fibers can be detected when glycemic control improves. In vivo CCM could be a sensitive method that can be applied in future longitudinal or interventional studies on DPN.

Understanding the pathophysiology of hyperglycemia-associated chorea-ballism: a systematic review of positron emission tomography findings

Hyperglycemia-associated chorea-ballism (HCB) is an infrequent neurological syndrome whose pathophysiology remains poorly understood. Positron emission tomography (PET) studies have offered valuable information regarding regional glucose metabolism. The studies included were published between 1980-2017 and reported demographic, clinical, laboratory and imaging data from patients with HCB in whom a PET scan had been performed. Eleven patients were evaluated (women 82%, Asian origin 91%, mean age 71 years). The main findings were an increase in glucose metabolism at the contralateral motor cortex related to recent episodes of hemiballism-hemichorea in 2 patients, and an altered metabolism in the affected basal ganglia in all of them: decreased in 10 patients (91%) and increased in 1 (9%). However during the acute period the patients showed only an increased metabolism, or even no changes. Contrary to what has previously been suggested in a metabolic failure hypothesis, changes in glucose metabolism in the basal ganglia may not be a key factor in the pathogenesis of HCB, and may potentially be a direct result of histological changes such as cellular ischemia and gliosis related to HCB development.

Chorea associated with nonketotic hyperglycemia: A case report with atypical imaging changes

INTRODUCTION

This is a unique case of nonketotic hyperglycemic (NKH) chorea in 84-year-old Asian woman. The patient had a history of type 2 diabetes mellitus more than 30 years, but had a poor control of blood sugar. She complained of acute onset of bilateral limb involuntary activities, and being easy to fall within a week. Laboratory testing disclosed hyperglycemia (669 mg/dL), glycated hemoglobin (14%), and normal ketones. The brain computed tomography scan and magnetic resonance imaging did not disclose any abnormality in the basal ganglion unlike most cases. The patient was then diagnosed with NKH chorea. Her symptoms improved quickly.

CONCLUSIONS

NKH chorea with normal imaging may represent a new subtype.

Hyperglycemia effect on coronary disease in patients with metabolic syndrome evaluated by intracoronary ultrasonography

INTRODUCTION

Metabolic syndrome (MS) is characterized by dyslipidemia, central obesity, hypertension and hyperglycemia. However, type 2 diabetes mellitus (T2DM) may or may not be present in metabolic syndrome. MS and T2DM are considered important cardiovascular risk factors, but the role of hyperglycemia in coronary disease is still contested in the literature. Therefore, we decided to evaluate the effect of hyperglycemia on the severity of coronary disease in MS patients, with or without T2DM, submitted to coronary angiography (CA) and intravascular ultrasonography (IVUS).

MATERIALS AND METHODS

This is a cross sectional, observational study with 100 MS patients (50% with T2DM), 60% male. All of the patients had been referred for CA procedures. The obstruction was considered severe when stenosis was greater than 70% and moderate if it was between 50-69%. Patients detected with a moderate obstruction by CA were indicated to IVUS. A minimal luminal area of less than 4mm2 detected by IVUS was also considered severe. IDF criteria were used to define Metabolic Syndrome and T2DM diagnosis was defined according to the American Diabetes Association criteria. Student's t-test and Pearson Chi-square were used for statistical analysis, considering p < 0.05 statistically significant.

RESULTS AND DISCUSSION

The majority of T2DM patients presented severe arterial lesions (74% vs 22%, p<0.001). Using CA procedure, 12% of T2DM had moderate obstructions, compared to 38% of the non-diabetic group (p< 0.05). 8% of patients with moderate lesions by CA were diagnosed with a luminal area less than 4mm2 using IVUS. This luminal area was significantly smaller in the T2DM group than in the control group (3.8mm2 ± 2.42. vs 4.6mm2 ± 2.58, p = 0.03).

CONCLUSION

Patients with MS and T2DM submitted to angiography and IVUS, had more severe coronary lesions compared to MS patients without diabetes. This finding suggests that beyond insulin resistance that is present in MS, hyperglycemia may also play a role in the development of atherosclerotic disease. IVUS was useful for diagnosing 8% of severe cases initially considered to be moderate obstructions when using just CA in this scenario.

Effect of hyperglycemia on brain and liver 18F-FDG standardized uptake value (FDG SUV) measured by quantitative positron emission tomography (PET) imaging

PURPOSE

Blood glucose is routinely measured prior to ¹⁸F-fluorodeoxyglucose (FDG) administration in positron emission tomography (PET) imaging to identify hyperglycemia that may affect image quality. In this study we explore the effects of blood glucose levels upon semi-quantitative standardized uptake value (SUV) measurements of target organs and tissues of interest and in particular address the relationship of blood glucose to FDG accumulation in the brain and liver.

METHODS

436 FDG PET/CT consecutive studies performed for oncology staging in 229 patients (226 male) at the Ann Arbor Veterans Administration Healthcare System were reviewed. All patients had blood glucose measured (112.4±34.1mg/dL) prior to injection of 466.2±51.8MBq (12.6±1.4mCi) of FDG. SUV measurements of brain, aortic arch blood-pool, liver, and spleen were obtained at 64.5±10.2min' post-injection.

RESULTS

We found a negative inverse relationship of brain SUV with increasing plasma glucose, levels for both absolute and normalized (either to blood-pool or liver) values. Higher blood glucose levels had a mild effect upon liver and blood-pool SUV. By contrast, spleen SUV was independent of blood glucose, but demonstrated the greatest variability (deviation on linear regression). In contrast to other tissues, liver and spleen SUV normalized to blood-pool SUV were not dependent upon blood glucose levels.

CONCLUSION

The effects of hyperglycemia upon FDG uptake in brain and liver, over a range of blood glucose values generally considered acceptable for clinical PET imaging, may have measurable effects on semi-quantitative image analysis.

[18F]FDG-PET scan in patients with fasting hyperglycemia

BACKGROUND

It is generally accepted that a non-fasting state reduces [18F]FDG-PET quality, but the significance of higher levels of fasting blood glucose has aroused some doubts over time. The aim of this work was to provide further evidence to clarify this issue and its impact on the handling of hyperglycemic patients in daily routine.

METHODS

Muscle and liver standardized uptake values (SUV) and their ratio, tumor SUV and the frequency of positive PET findings were retrospectively analyzed in 116 hyperglycemic (HG) patients (>11 mmol/L), in 116 patients with slightly elevated glycemia (SEG) (5.6-7.0 mmol/L) and in 116 normoglycemic (NG) patients (4.7 mmol/L).

RESULTS

No significant difference was found in the muscle to liver ratio, in muscle SUV and in the frequency of positive PET findings among HG, SEG and NG patients. HG patients exhibited ~10% higher liver SUV in comparison to SEG and NG patients; a positive correlation (r=0.2849) was found between liver SUV and blood glucose levels. Significantly higher tumor SUV was present in SEG patients.

CONCLUSIONS

We did not confirm that hyperglycemia in a fasting state negatively influences the diagnostic quality of [18F]FDG-PET. The positive correlation between liver SUV and blood glucose levels is clinically negligible and might be explained by increased fasting hepatic gluconeogenesis in diabetics. Our data encourage the performance of [18F]FDG-PET investigations under fasting conditions, regardless of the mild to medium elevation of fasting blood glucose level.

A novel imaging platform for non-invasive screening of abnormal glucose tolerance

Optical measurement of skin auto-fluorescence (SAF), most likely emanating from accumulated advanced glycation end-products (AGEs), has been proposed for the noninvasive diagnosis of glucose intolerance in clinical settings. Here, we developed a novel imaging system with transmission geometry for SAF measurement and compared its diagnostic performance in a Korean population.

Epicardial and pericardial fat in type 2 diabetes: favourable effects of biliopancreatic diversion

PURPOSE

Ectopic fat is often identified in obese subjects who are susceptible to the development of type 2 diabetes mellitus (T2DM). The ectopic fat favours the decrease in insulin sensitivity (IS) and adiponectin levels. We aimed to evaluate the effect of biliopancreatic diversion (BPD) on the accumulation of ectopic fat, adiponectin levels and IS in obese with T2DM.

MATERIALS AND METHODS

A nonrandomised controlled study was performed on sixty-eight women: 19 lean-control (23.0 ± 2.2 kg/m(2)) and 18 obese-control (35.0 ± 4.8 kg/m(2)) with normal glucose tolerance and 31 obese with T2DM (36.3 ± 3.7 kg/m(2)). Of the 31 diabetic women, 20 underwent BPD and were reassessed 1 month and 12 months after surgery. The subcutaneous adipose tissue, visceral adipose tissue, epicardial adipose tissue and pericardial adipose tissue were evaluated by ultrasonography. The IS was assessed by a hyperglycaemic clamp, applying the minimal model of glucose.

RESULTS

One month after surgery, there was a reduction in visceral and subcutaneous adipose tissues, whereas epicardial and pericardial adipose tissues exhibited significant reduction at the 12-month assessment (p < 0.01). Adiponectin levels and IS were normalised 1 month after surgery, resembling lean-control values and elevated above the obese-control values (p < 0.01). After 12 months, the improvement in IS and adiponectin was maintained, and 17 of the 20 operated patients exhibited fasting glucose and glycated haemoglobin within the normal range.

CONCLUSIONS

After BPD, positive physiological adaptations occurred in grade I and II obese patients with T2DM. These adaptations relate to the restoration of IS and decreased adiposopathy and explain the acute (1 month) and chronic (12 months) improvements in the glycaemic control.

Glucose-related arterial stiffness and carotid artery remodeling: a study in normal subjects and type 2 diabetes patients

CONTEXT

Hyperglycemia is associated with a higher carotid intima-media thickness (IMT); however, it is not established whether this increase reflects early atherosclerotic changes or adaptive remodeling responding to hyperglycemia-induced alteration in mechanical properties of the arterial wall.

OBJECTIVE

The aims of this study were to compare carotid geometry and circumferential wall stress between patients with type 2 diabetes mellitus (T2DM) and healthy controls and to evaluate the associations between chronic glucose exposure and measures of arterial structure and function.

DESIGN AND SETTING

This was a case-control and cross-sectional study within institutional practice.

PARTICIPANTS

PARTICIPANTS included 133 T2DM patients free of cardiovascular complications and 133 healthy controls with normal glucose metabolism, matched for sex, age, and body mass index.

MAIN OUTCOME MEASURES

Common carotid artery (CCA) IMT, luminal diameter, wave speed, and local pulse pressure (PP) were evaluated.

RESULTS

As compared with controls, T2DM patients had higher (P < .0001) CCA IMT (640 ± 81 vs 709 ± 118 μm), luminal diameter (6.12 ± 0.67 vs 6.69 ± 0.56 mm), and brachial PP (47 ± 7 vs 57 ± 12 mm Hg), whereas luminal radius to IMT ratio (4.8 ± 0.7 vs 4.8 ± 0.8, P = .57) and circumferential wall stress (49.0 ± 8.3 vs 50.6 ± 10.3 kPa, P = .26) were comparable between the 2 groups. In T2DM patients, glycosylated hemoglobin was independently related to CCA wave speed and local PP, but not to IMT that was determined by age, local PP, and luminal diameter.

CONCLUSIONS

This study suggests that the increase in IMT associated with a higher glucose exposure might reflect adaptive remodeling counteracting an increase in pulsatile strain and preventing increase in circumferential wall stress caused by luminal enlargement of stiff arteries.

Abnormalities of myocardial perfusion and glucose metabolism in patients with isolated left ventricular non-compaction

BACKGROUND

The prevalence of myocardial perfusion and glucose metabolic abnormalities and their significance in patients with isolated left ventricular non-compaction (ILVNC) have not been well investigated.

METHODS

Seventeen ILVNC patients who underwent cardiac magnetic resonance (CMR) and (99m)Tc-sestamibi SPECT/fluorine-18 deoxyglucose ((18)F-FDG) PET imaging were included. Left ventricular non-compaction, regional wall motion abnormalities, left ventricular ejection fraction (LVEF), and delayed enhancement (DE) were estimated using CMR. Myocardial perfusion and metabolism were evaluated with SPECT/PET.

RESULTS

Ninety-five (32.9%) segments were considered non-compacted. DE was present in 52 (18.0%) segments and 10 (58.8%) patients. The rate of occurrence of DE was significantly higher in compacted segments than in non-compacted segments (22.7% vs 8.4%, P = .003). Myocardial perfusion abnormalities were present in 92 (31.8%) segments, of which 66 were perfusion/metabolism match and 26 were perfusion/metabolism mismatch. The rate of occurrence of perfusion abnormality was similar between compacted and non-compacted segments (32.0% vs 31.6%, P = .948), but it was significantly higher in segments with DE than in those without DE (51.9% vs 27.4%, P = .001). None of the imaging features alone (non-compaction, DE, perfusion abnormalities, match or mismatch) showed significant correlations with LVEF (all P > .05).

CONCLUSION

In the current study, myocardial perfusion/metabolism mismatch and match were observed in both non-compacted and compacted myocardium in ILVNC patients. Further research is warranted to determine their pathologic and clinical significance.

Dynamic PET imaging reveals heterogeneity of skeletal muscle insulin resistance

PURPOSE

Skeletal muscle insulin resistance (IR) often precedes hyperglycemia and type 2 diabetes. However, variability exists within different skeletal muscle types and can be influenced by 3 primary steps of control: glucose delivery, transport, and phosphorylation. We performed dynamic positron emission tomography imaging studies to determine the extent to which heterogeneity in muscle type and control of insulin action contribute to IR.

METHODS

Thirteen volunteers from normal weight to obese underwent dynamic positron emission tomography imaging of [15O]H2O, [11C]3-O-methylglucose, and [18F]fluorodeoxyglucose, measuring delivery, transport, and phosphorylation rates, respectively, in soleus and tibialis anterior muscle during a hyperinsulinemic-euglycemic clamp. Subjects were classified as insulin-sensitive (IS) or insulin-resistant (IR) based on the median systemic glucose infusion rate needed to maintain euglycemia.

RESULTS

In soleus, transport kinetic rates were significantly higher (P<.05) in IS (0.126±0.028 min(-1)) vs IR (0.051±0.008 min(-1)) subjects. These differences were not as evident in tibialis anterior. These differences were paralleled in overall insulin-stimulated tissue activity, higher in IS (0.017±0.001 mL·cm3·min(-1)) vs IR (0.011±0.002 mL·cm3·min(-1)) in soleus (P<.05), without significant differences in tibialis anterior. No significant differences were observed for either muscle in delivery or phosphorylation. Both muscle types displayed a control shift from an even distribution among the steps in IS to transport exerting greater control of systemic insulin sensitivity in IR.

CONCLUSION

Lower glucose transport rates are the major feature underlying IR preceding type 2 diabetes, although substantial heterogeneity in insulin action across muscle types highlight the complexity of skeletal muscle IR.

[Doppler studies of gestational diabetes in the third trimester]

PURPOSE

Gestational diabetes (GDM) is related to increased maternal and neonatal morbidity. Maternal hyperglycemia causes fetal hyperglycemia and consequently fetal hyperinsulinism. The impaired glucose metabolism will lead to prenatal and postnatal complications. The main issue of this study is the influence of GDM in evaluating Doppler flow measurements in the umbilical artery (UA).

MATERIALS AND METHODS

Pregnancies from gestational age > 34 + 0 were included in this case control study. The study period was 18 months. The last Doppler measurement in pregnancies with GDM (diet-controlled and insulin-dependent) was compared to the healthy control group. Our collected data included the last prenatal Doppler flow recordings (resistance index (RI) in the umbilical artery (UA)).

RESULTS

In women with diet-controlled GDM, a significant decrease in the RI (p = 0.002) in the UA has been observed. Insulin-treated diabetic and healthy control pregnancies showed no difference in the RI.

CONCLUSION

Doppler flow examinations with RI measurements in patients with GDM differ significantly with respect to healthy controls. In insulin-treated women the RI indices are not different from the control group, while in the diet-controlled group a significant decrease was noted and additionally might show a possible maternal metabolic dysfunction.

Localized fetomaternal hyperglycemia: spatial and kinetic definition by positron emission tomography

BACKGROUND

Complex but common maternal diseases such as diabetes and obesity contribute to adverse fetal outcomes. Understanding of the mechanisms involved is hampered by difficulty in isolating individual elements of complex maternal states in vivo. We approached this problem in the context of maternal diabetes and sought an approach to expose the developing fetus in vivo to isolated hyperglycemia in the pregnant rat.

METHODOLOGY AND PRINCIPAL FINDINGS

We hypothesized that glucose infused into the arterial supply of one uterine horn would more highly expose fetuses in the ipsilateral versus contralateral uterine horn. To test this, the glucose tracer [18F]fluorodeoxyglucose (FDG) was infused via the left uterine artery. Regional glucose uptake into maternal tissues and fetuses was quantified using positron emission tomography (PET). Upon infusion, FDG accumulation began in the left-sided placentae, subsequently spreading to the fetuses. Over two hours after completion of the infusion, FDG accumulation was significantly greater in left compared to right uterine horn fetuses, favoring the left by 1.9+/-0.1 and 2.8+/-0.3 fold under fasted and hyperinsulinemic conditions (p<10(-11) n=32-35 and p<10(-12) n=27-45) respectively. By contrast, centrally administered [3H]-2-deoxyglucose accumulated equally between the fetuses of the two uterine horns. Induction of significant hyperglycemia (10(3) mg/dL) localized to the left uterine artery was sustained for at least 48 hours while maternal euglycemia was maintained.

CONCLUSIONS AND SIGNIFICANCE

This approach exposes selected fetuses to localized hyperglycemia in vivo, minimizing exposure of the mother and thus secondary effects. Additionally, a set of less exposed internal control fetuses are maintained for comparison, allowing direct study of the in vivo fetal effects of isolated hyperglycemia. Broadly, this approach can be extended to study a variety of maternal-sided perturbations suspected to directly affect fetal health.

Hyperglycemia on admission predicts larger infarct size in patients undergoing percutaneous coronary intervention for acute ST-segment elevation myocardial infarction

AIMS

To determine if hyperglycemia on admission correlates to infarct size measured by single-photon emission computed tomography (SPECT) in patients with acute ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI).

METHODS

We evaluated 347 STEMI patients who underwent primary PCI. Infarct size was determined by SPECT on Day 5. The population was divided into: hyperglycemia (glycemia on admission >11mmol/L) or non-hyperglycemia (<or=11mmol/L) regardless of diabetic status.

RESULTS

61 (17.6%) patients presented with hyperglycemia on admission. There were no significant differences in baseline characteristics or in PCI characteristics between the two groups. Final TIMI 3 flow was achieved in 81.7% of patients with hyperglycemia vs 85.7% of patients with non-hyperglycemia (p=0.43). The infarct size was larger in the hyperglycemia group (6 [2-14]% vs 8.5 [3-18.25]%; p=0.016). A multivariate linear regression analysis showed that hyperglycemia on admission was an independent predictor of infarct size at Day 5 post-MI (p=0.004).

CONCLUSION

In patients with STEMI treated with primary PCI, hyperglycemia on admission is associated with larger infarct size determined by SPECT.

[Sonographic ovarian vascularization and volume in women with polycystic ovary syndrome treated with clomiphene citrate and metformin]

OBJECTIVE

To measure the vascularization and ovarian volume with three-dimensional sonography in patients diagnosed of polycystic ovary syndrome with stimulated ovulation treatment, and to analyse the differences between the patients treated with clomiphen citrate versus clomiphen citrate and metformin.

MATERIAL AND METHOD

Therty patients were studied. Twenty ovulation cycles were obtained with clomiphen citrate and 17 with clomiphen citrate plus merformin (added in case of obesity or hyperglucemy/hyperinsulinemia). Ovarian volumes and vascular indexes were studied with 3D-sonography and results were analysed by treatment.

RESULTS

There were no statistical differences of ovarian volume by treatment along the cycles, although bigger volume were found in ovulatory cycles compared to non-ovulatory ones (20,36 versus 13,89 ml, p = 0,026). No statistical differences were also found concerning vascular indexes, neither by treatment nor by the obtention of ovulation in the cycle.

CONCLUSIONS

Ovarian volume and vascular indexes measured with three-dimensional sonography in patients diagnosed of polycystic ovary syndrome do not show differents values in patients treated with clomiphen citrate alone versus clomiphen citrate plus metformin.

Relationship between hyperglycemia and coronary vascular resistance in non-diabetic patients

BACKGROUND

Hyperglycemia upon hospital admission in patients with acute myocardial infarction is associated with the no-reflow phenomenon after successful reperfusion, and increased mortality. However, the mechanism underlying this phenomenon remains unclear. Therefore, the aim of this study was to characterize coronary hemodynamics in a homogenous group of non-diabetic patients without coronary artery disease.

METHODS AND RESULTS

A total of 104 consecutive non-diabetic patients (mean age, 62+/-14 years) without coronary artery disease underwent Doppler flow study of the left anterior descending coronary artery. Vascular reactivity was examined by intra-coronary administration of papaverine, acetylcholine (Ach), and nitroglycerin using a Doppler guidewire. Coronary vascular resistance (CVR) was calculated as the mean arterial pressure divided by coronary blood flow (CBF). Baseline CVR was shown as CVR at control and minimal CVR was shown as CVR with papaverine administration. Fasting plasma glucose (FPG) level had a significant, positive correlation with baseline CVR and minimal CVR (r=0.24, p<0.02 and r=0.21, p<0.05, respectively). Hemoglobin A1c (HbA1c) also had a significant, positive correlation with baseline CVR and minimal CVR (r=0.31, p<0.01 and r=0.32, p<0.01, respectively). The percent change in CBF induced by Ach was inversely correlated with HbA1c but not with FPG (r=0.22, p<0.05 and r=0.06, p=0.57, respectively). By contrast, neither FPG nor HbA1c had significant correlation with coronary flow reserve to papaverine.

CONCLUSION

These data demonstrate that elevated glucose levels are associated with increases in baseline and minimal coronary vascular resistance. These changes may contribute to unfavorable coronary hemodynamics in non-diabetic patients without coronary heart disease.

Insular cortex hypoperfusion and acute phase blood glucose after stroke: a CT perfusion study

BACKGROUND AND PURPOSE

Insular cortex ischemia is proposed to mediate a sympathetic stimulus that leads to acute hyperglycemia after stroke.

METHODS

We retrospectively analyzed insular perfusion on perfusion CT (median 180 minutes after onset) in 35 patients.

RESULTS

We found no association of hypoperfusion (relative cerebral blood flow <0.51) with early (<6 hours) or delayed (<72 hours) hyperglycemia, or hemispheric lateralization.

CONCLUSIONS

Insular cortex hypoperfusion <6 hours after stroke onset was not associated with hyperglycemia.

Acute Hyperglycemia Induced by Oral Glucose Loading Suppresses Coronary Microcirculation on Transthoracic Doppler Echocardiography in Healthy Young Adults

OBJECTIVES

We sought to evaluate the effect of acute hyperglycemia on coronary microcirculation by noninvasive measurement of coronary flow velocity reserve (CFVR) using transthoracic Doppler echocardiography (TTDE).

RESEARCH DESIGN AND METHODS

Measurements of CFVR using TTDE and levels of plasma glucose and serum insulin and lipids were determined before and 1 hour after loading with oral glucose (75-g glucose) in 10 young healthy males (mean age, 30 +/- 2 years) or an artificial sweetener in five of the 10 subjects without coronary risk factors.

RESULTS

In all subjects, the levels of plasma glucose and serum insulin significantly increased after glucose loading compared with baseline (5.1 +/- 0.6 vs 7.6 +/- 1.2 mM/l, 6 +/- 3 vs 49 +/- 13 microU/ml, respectively; P < 0.0001). CFVR was significantly decreased 1 hour after acute oral glucose loading (4.4 +/- 0.7-3.8 +/- 0.7, respectively; P < 0.01). There was no significant change in CFVR after loading with an artificial sweetener (4.4 +/- 0.6-4.4 +/- 0.5 cm/sec).

CONCLUSIONS

TTDE revealed that acute hyperglycemia induced by oral glucose loading suppresses CFVR in healthy young male subjects. This result suggests that acute hyperglycemia may have adverse effects on coronary microcirculation.

Myocardial insulin resistance associated with chronic hypertriglyceridemia and increased FFA levels in Type 2 diabetic patients

We evaluated the influence of chronic hypertriglyceridemia and endothelial dysfunction on myocardial glucose uptake (MGU) in Type 2 diabetic patients without coronary heart disease. Patients were divided into two groups according to fasting triglyceride (TG) levels: 5.4 ± 1.1 and 1.5 ± 0.3 mmol/l for high- and normal-TG groups, respectively. Five subjects were assigned to the high-TG group and 11 to the normal-TG group. Age, gender, body mass index, systolic and diastolic blood pressure, glucose, insulin, HbA1c, cholesterol, and HDL cholesterol were similar in the two groups, whereas free fatty acid (FFA) levels were higher in the high-TG group basally and at the end of the clamp. Furthermore, five healthy subjects were subjected to the same protocol and used as the control group. MGU was assessed by using 18F-labeled 2-fluoro-2-deoxy-d-glucose under hyperglycemic-hyperinsulinemic conditions. Basal endothelin-1 and nitric oxide levels were significantly higher in the high-TG group than in the normal-TG and control groups, and cGMP and maximal postischemic vasodilation were significantly decreased in the high-TG group compared with the normal-TG and control groups. However, significant alterations were found in the same parameters in the normal-TG group compared with the control group. By the end of the hyperglycemic clamp, in the high-TG group, MGU was ∼40 and 65% of that in the normal-TG and control groups. MGU negatively correlated with TG, FFA, and endothelin-1, whereas a positive correlation was found with cGMP and maximal postischemic vasodilation. In conclusion, increased TG and FFA levels are risks, in addition to Type 2 diabetes mellitus, for myocardial insulin resistance, endothelial dysfunction, and alteration of nitric oxide/cGMP levels.

Doppler sonographic characteristics of umbilical and uterine arteries during oral glucose tolerance testing in healthy pregnant women

PURPOSE

Studies have shown that maternal hyperglycemia may be associated with increased placental resistance to blood flow and possibly adverse perinatal outcomes. The aim of this study was to determine whether Doppler velocimetric dynamics change in the uterine and umbilical arteries in healthy pregnant women (without gestational diabetes) during acute hyperglycemia induced by oral glucose tolerance testing.

METHODS

Flow in the umbilical and right and left uterine arteries was assessed by spectral Doppler sonographic examination of healthy pregnant women at 24-28 weeks' menstrual age. Four Doppler studies were conducted for each woman: 1 before oral administration of 100 g of glucose and 3 more at 1, 2, and 3 hours after glucose administration. The systolic-to-diastolic ratio was calculated for the umbilical artery, and the resistance index was calculated separately for the left and right uterine arteries.

RESULTS

All results of oral glucose tolerance testing were normal, and Doppler signals were obtained in all 30 patients enrolled. No abnormal systolic-to-diastolic ratios or resistance indices were detected in any of the examinations. No significant differences in waveforms or resistance indices between the right and left uterine arteries were found during the various testing intervals.

CONCLUSIONS

Acute hyperglycemia induced in healthy pregnant women does not affect blood flow velocimetric characteristics in the umbilical or uterine arteries at any stage of oral glucose tolerance testing.

Effect of postprandial hyperglycaemia in non-invasive measurement of cerebral metabolic rate of glucose in non-diabetic subjects

The aim of this study was to determine the effect of postprandial hyperglycaemia (HG) on the non-invasive measurement of cerebral metabolic rate of glucose (CMRGlc). Five patients who had a meal within an hour before a fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) examination were recruited in this study. They underwent intermittent arterial blood sampling (measured input function), and, based on this sampling, CMRGlc was calculated using an autoradiographic method (CMRGlc(real)). Simulated input functions were generated based on standardised input function, body surface area and net injected dose of FDG, and simulated CMRGlc (CMRGlc(sim)) was also calculated. Percent error of the area under the curve (AUC) between measured (AUC(real)) and simulated input function (AUC(IFsim)) and percent error between CMRGlc(real) and CMRGlc(sim) were calculated. These values were compared with those obtained from a previous study conducted under fasting conditions (F). The serum glucose level in the HG group was significantly higher than that in the F group (165+/-69 vs 100+/-9 mg/dl, P=0.0007). Percent errors of AUC and CMRGlc in grey matter and white matter in HG were significantly higher than those in F (12.9%+/-1.3% vs 3.5%+/-2.2% in AUC, P=0.0015; 18.2%+/-2.2% vs 2.9%+/-1.9% in CMRGlc in grey matter, P=0.0028; 24.0%+/-4.6% vs 3.4%+/-2.2% in CMRGlc in white matter, P=0.0028). It is concluded that a non-invasive method of measuring CMRGlc should be applied only in non-diabetic subjects under fasting conditions.

[Hemichorea, hemiballism disclosing non-ketotic hyperglycemia]

Non ketotic hyperglycemia is a metabolic disorder which can induce various hyperkinetic disorders. We report the case of a 74-year old woman admitted to hospital because of choreo-ballic movements of her left hemibody. Laboratory tests revealed non-ketotic hyperglycemia. CT scan showed an increased density in the right putamen and head of caudate. Magnetic resonance imaging disclosed a hyperintense signal involving the right putamen on T1-weighted images. On T2-weighted images, there was a slight hyperintensity in the right putamen and head of caudate. Correction of the underlying hyperglycemia led to complete resolution of abnormal movements. Pathophysiology of this clinicoradiologic syndrome is briefly discussed.

Induced-hyperglycemia attenuates erythromycin-induced acceleration of hypertonic liquid-phase gastric emptying in type-I diabetic patients

BACKGROUND

Erythromycin has been found to be a gastrointestinal prokinetic agent of hypertonic liquids, while acute hyperglycemia has been associated with delayed gastric emptying in diabetic patients.

AIM

To investigate whether hyperglycemia, per se, reduces gastric motility during erythromycin-induced acceleration on gastric emptying of hypertonic liquids in diabetic patients.

METHODS

In 12 type-I diabetic patients following a hypertonic radiolabeled liquid meal, gastric emptying was measured scintigraphically during normoglycemia (5-8.9 mmol/l glucose) or hyperglycemia induced by intravenous (16-19 mmol/l) glucose infusion. The tests were performed on 4 separate days in random order after administering either placebo or 200 mg i.v. erythromycin.

RESULTS

In the hyperglycemic state compared to normoglycemia, the gastric emptying of the hypertonic liquid was reduced after placebo or erythromycin administration. The lag-phase duration (17.8+/-5.5 and 7.8+/-4.5 vs. 10.8+/-3.4 and 3.7+/-2.5 min, respectively, p<0.001), the overall gastric emptying time of the half meal (52.8+/-13 and 24.9+/-5.5 vs. 42.5+/-10.5 min and 16.6+/-6 min, respectively, p<0.001) and the retained percentage of liquid meal in the stomach at 60 and 100 min postprandially (p<0.001) were significantly increased.

CONCLUSIONS

The erythromycin-induced acceleration on gastric emptying of hypertonic liquids in diabetic patients is related to the plasma glucose level. The induced hyperglycemia reduces the erythromycin-induced acceleration of liquid-phase gastric emptying, decreasing the overall gastric emptying rate. In spite of the inhibitory effect of induced hyperglycemia on the gastric emptying of hypertonic liquids, erythromycin is still able to accelerate the emptying rate and could prove to be a useful prokinetic agent under hyperglycemic conditions.

The effect of hyperglycaemia on regional cerebral glucose oxidation in humans studied with [1-11C]-D-glucose

The effect of hyperglycaemia on regional cerebral glucose utilization was studied in five healthy males fasted over-night using positron emission tomography. Selectively labelled glucose, [1-11C]-D-glucose, was used as a tracer. After correction for the small loss of [11C]CO2 from the tissue, this tracer measures the rate of glucose oxidation rather than the total rate of glucose metabolism. Each subject was investigated twice: during normoglycaemia (plasma glucose 5.3 +/- 0.3 mumol mL-1) and at the end of a 2-h period of hyperglycaemia (plasma glucose 13.8 +/- 0.7 mumol mL-1). Assuming unchanged rate constant for loss of labelled CO2 at normo- and hyperglycaemia the oxidative metabolic rate of glucose was found to be slightly larger at combined hyperglycaemia and hypersulinemia (0.30 +/- 0.01 mmol mL-1 min-1) than at normal glucose and insulin levels (0.25 +/- 0.01 mmol mL-1 min-1). This suggests that the process of glucose phosphorylation might not be fully saturated in the human brain or, alternatively, that the glycogen deposition increases during short-term hyperglycaemia. The relative increase of oxidative metabolic rate was considerably larger (approximately 50%) in white matter than in the brain as a whole (20%). The brain glucose content was found to increase non-linearly with increasing plasma glucose. Together with data from previous studies these results suggest that the free glucose in the human brain is close to zero when the plasma glucose is below 2 mumol mL-1.

Hepatitis, hyperglycemia, pleural effusion, eosinophilia, hematuria and proteinuria occurring early in clozapine treatment

This report describes a 48-year-old caucasian male with schizophrenia who developed hepatitis, hyperglycemia, pleural effusion, eosinophilia, hematuria and proteinuria early in clozapine treatment which resolved on drug discontinuation. The literature on similar cases is reviewed.

The effect of maternal glycemic control on fetal growth in diabetic pregnancies

In this prospective study, we examined the effect of maternal glycemic control on fetal growth in pregnancies complicated by pregestational diabetes. One hundred and sixty-five pregestational diabetic pregnancies were studied with serial ultrasound scans and fetal growth was examined as a function of maternal glycemic control. There was a significant, although small, reduction in fetal biparietal diameter growth rate in the presence of poor maternal glycemic control during the first half of the pregnancy. In the second half of pregnancy, maternal hyperglycemia contributed to fetal macrosomia. We conclude that in pregnancies with pregestational diabetes, maternal hyperglycemia affects fetal growth in a biphasic manner. As a result of that, although babies born to diabetic mothers appear of relatively overall normal size and weight, they may have smaller heads than their potential and more fat.

Prognostic implications of hyperglycemia and reduced cerebral blood flow in childhood near-drowning

We retrospectively examined the clinical courses of 20 children with severe near-drowning and divided their outcomes into 3 groups: normal (4), persistent vegetative state (9), and dead (7). We reviewed serial blood glucose levels and cerebral blood flow measured by stable xenon computed tomography within the 1st 48 hours of admission to determine whether they were predictive of outcome. Total, frontal gray, frontal white, and temporal and parietal gray matter cerebral blood flows were significantly decreased in children who died compared with those who completely recovered. Only 1/2 the children surviving in a vegetative state had decreased flows compared with those who recovered. An elevated initial blood glucose was highly predictive of those patients who died (mean, 511 +/- 110 mg%) or those with vegetative survival (465 +/- 104 mg%) compared with those who recovered completely (238 +/- 170 mg%). The predictive value of initial blood glucose alone (68%) or CBF alone (50%) was similar to that of clinical rating scales or immersion/resuscitation times. The combination of blood glucose with CBF improved predictability to 79%. Our results suggest that CBF measurements are predictive of eventual death but cannot differentiate normal from vegetative survival. Combining multiple laboratory studies may be of value in predetermining the eventual outcome in near-drowning.