Asymmetrical influence of a standard light/dark cycle and constant light conditions on the alanyl-aminopeptidase activity of the left and right retinas in adult male rats.

The retina acts as an independent clock informing the central pacemaker, the suprachiasmatic nucleus, under environmental light conditions, with consequences of such inputs for the central and peripheral nervous system. Differences in the behavior of the left and right retinas depending on environmental light conditions may influence the information projected to the brain hemispheres. The retina possesses neuropeptides that act as neurotransmitters or neuromodulators. Alanyl-aminopeptidase (AlaAP, EC 3.4.11.2) activity regulates some of these neuropeptides and therefore reflects their function. We analyzed AlaAP activity in the left and right retinas of adult male rats at successive time points under standard (12/12 h light/dark cycle) and nonstandard (constant light) conditions. AlaAP activity was measured fluorometrically using alanyl-beta-naphthylamide as the substrate. Under standard conditions, there were no differences in the left or right retina between time points, with the left retina predominating, particularly in the light period. In contrast, under constant light, no left versus right differences were observed, but significant differences between time points appeared. In comparison with standard conditions, constant conditions led to significantly higher AlaAP activity. Considering all the left retina data in comparison with all the right retina data, no correlation was found between the left and right retinas under standard conditions, but a significant positive correlation was observed under constant light. These results demonstrate an asymmetrical response of retinal AlaAP activity to changes in environmental light conditions, which may affect the functions in which the substrates of AlaAP are involved and the information projected to the brain hemispheres.

The reactivation time in the treatment of AMD: a forgotten key parameter?

OBJECTIVE: Summarize and compare the available evidence on the reactivation times in patients with age-related macular degeneration treated with Ranibizumab (RNB). METHOD: Systematic review of studies that reported the reactivation time of patients (direct method) or the number of injections received in a certain period of follow-up (indirect method). RESULTS: Only 18 of 89 selected studies reported the average reactivation time of patients in a manifest form, without the need of any calculation. The average calculated, weighted reactivation time was 101.8 days with the direct method and 99.8 days in the indirect method (84 studies included). With both methods, it was found that the average reactivation time of the RCTs was between 2 and 3 weeks less than the average time identified in the observational studies. These differences are also reflected in the clinical results, there being a correlation between the number of doses received and the change in BCVA. The analysis of 11 comparative studies showed a difference in reactivation times between patients treated with RNB or Bevacizumab (BVZ). CONCLUSION: There are few direct studies of reactivation time, but calculation from the PRN dose number turns out to be a good approximation for retrospective study of the variable. The use of the PRN, with criteria not based on optical coherence tomography scans, delays the application of doses between 2 or 3 weeks, and patients suffer loss of clinical benefits. RNB enables patients to receive less injections than BVZ throughout treatment.

Trends in the dispensation of antidepressant drugs over the past decade (2000-2010) in Andalusia, Spain.

PURPOSE: To study antidepressant drug dispensation in the Spanish region of Andalusia and in the Almeria Health Area (AHA) over the past decade, analyzing the variability, trends, and influential factors. METHODS: We conducted an observational ecological study of antidepressant drug dispensation between 2000 and 2010 in Andalusia. Dispensation was measured as Defined Daily Dose (DDD) per 1,000 inhabitants per day. A multilevel analysis (STATA 11.1) was performed to determine the variability among the basic health zones (BHZs) (2004-2010) and influential factors. RESULTS: Between 2000 and 2010, the total dispensation of antidepressant drugs increased by more than 100 % in Andalusia and in the AHA. This increase was primarily caused by the greater dispensation of selective serotonin reuptake inhibitors (ATC-N06AB) and other antidepressants (ATC-N06AX). Multilevel analysis revealed a wide variability in the levels and trends of antidepressant dispensation among BHZs. Urbanicity and the percentage of immigrants in the BHZ were negatively associated with their dispensation, which was positively influenced by a higher proportion of women and over 65-year-olds in the population. CONCLUSIONS: The elevated dispensation of several groups of antidepressant drugs in this study population indicates the need for health policies to rationalize their use. Further research is required into the differences in antidepressant dispensations between immigrant and native populations and the implications for public health policies.

Immunohistochemical localization of low density lipoprotein receptor-related protein 1 and alpha(2)-Macroglobulin in retinal and choroidal tissue of proliferative retinopathies.

The immunolocalization of the low density lipoprotein receptor-related protein 1 (LRP1) and its ligand alpha 2-Macroglobulin (alpha(2)M) was examined in tissues from human donor eyes of normal, diabetic and sickle cell disease subjects. Streptavidin alkaline phosphatase immunohistochemistry was performed with a mouse anti-human LRP1 and rabbit anti-human alpha(2)M antibodies. Retinal and choroidal blood vessels were labeled with mouse anti-human CD34 antibody in adjacent tissue sections. Mean scores for immunostaining from the pathological and control eyes were statistically compared. LRP1 immunoreactivity was very weak to negative in the neural retina of normal subjects except in scattered astrocytes. LRP1 expression in diabetic eyes was detected in the internal limiting membrane (ILM), astrocytes, inner photoreceptor matrix, choriocapillaris and choroidal stroma. The ligand alpha(2)M, however, was limited mainly to blood vessel walls, some areas of the inner nuclear layer (INL), photoreceptors, RPE-Bruch's membrane-choriocapillaris complex, intercapillary septa, and choroidal stroma. In sickle cell eyes, avascular and vascular retina as well as choroidal neovascularization (CNV) were analyzed. In avascular areas, LRP1 immunoreactivity was in innermost retina (presumably ILM, astrocytes, and Muller cells) and INL as well as RPE-Bruch's membrane-choriocapillaris complex and choroidal stroma. alpha(2)M was very weak in avascular peripheral retina compared to vascularized areas and limited to stroma in choroid. In contrast, in areas with CNV, LRP1 immunoreactivity was significantly decreased in overlying retina and in RPE-Bruch's membrane and choroidal stroma compared to the controls, while alpha(2)M was elevated in RPE-Bruch's membrane near CNV compared to normal areas in sickle cell choroid. The mean scores revealed that LRP1 and alpha(2)M in neural retina were significantly elevated in astrocytes and ILM in diabetic eyes (p < or = 0.05), whereas in sickle cell eyes scores were elevated in ILM and INL (p < or = 0.05). In addition, alpha(2)M immunoreactivity was in photoreceptors in both ischemic retinopathies. In choroid, the patterns of LRP1 and alpha(2)M expression were different and not coincident. This is the first demonstration of the presence of LRP1 and alpha(2)M in human proliferative retinopathies. Elevated LRP1 expression in sickle cell neural retina and diabetic inner retina and choroid suggests that LRP1 plays an important role in ischemic neovascular diseases.

Triamcinolone acetonide-loaded lipid nanocapsules for ophthalmic applications.

Triamcinolone acetonide (TA) is an effective drug widely (off-label) used in the treatment of several ocular diseases involving inflammation and angiogenic processes. However, the use of TA ocular presents some limitations mainly related to its excipient composition, as in the case of benzyl alcohol. Thus, the aim of this work was to obtain an alternative TA formulation based on lipid nanocapsules (LNCs). Triamcinolone acetonide-loaded lipid nanocapsules (TA-LNCs) were obtained by the phase inversion temperature process without the use of irritating excipients, by combining lipids and surfactants generally recognized as safe. Pre-formulation studies were carried out to evaluate the TA solubility in different co-surfactants and to optimize the lipid core composition in order to enhance the drug loading and encapsulation rate in the LNCs. A stable final TA-LNC formulation was obtained with a mean particle size (MPS) of below 50 nm, a narrow size distribution (PDI < 0.2), a negative zeta potential (ZP) and a high encapsulation efficiency (%EE > 98%). In vitro cellular viability assays revealed that blank LNCs and TA-LNCs at 0.1 µg/mL did not affect the viability of the human corneal epithelial (HCE) cells. TA-LNCs showed a high anti-inflammatory activity below the toxicity level, with a reduction of 30% in interleukin (IL)-6 secretion observed in an in vitro model using the same cell line. More importantly, the TA-LNCs revealed a therapeutic efficacy in the endotoxin-induced uveitis (EIU) rabbit model with a significant attenuation of clinical signs of an inflammatory response. These findings make the TA-LNCs a safer and more efficient alternative for the treatment of eye disorders.

Radiation-induced DNA damage as a predictor of long-term toxicity in locally advanced breast cancer patients treated with high-dose hyperfractionated radical radiotherapy.

This 14-year-long study makes a novel contribution to the debate on the relationship between the in vitro radiosensitivity of peripheral blood lymphocytes and normal tissue reactions after radiation therapy. The aims were (1) to prospectively assess the degree and time of onset of skin side effects in 40 prospectively recruited consecutive patients with locally advanced breast cancer treated with a hyperfractionated dose-escalation radiotherapy schedule and (2) to assess whether initial radiation-induced DNA damage in peripheral blood lymphocytes of these patients could be used to determine their likelihood of suffering severe late damage to normal tissue. Initial radiation-induced DNA double-strand breaks (DSBs) were assessed in peripheral blood lymphocytes of these patients by pulsed-field electrophoresis. Acute and late cutaneous and subcutaneous toxicity was evaluated using the Radiation Therapy Oncology Group morbidity score. A wide interindividual variation was observed in toxicity grades and in radiation-induced DNA DSBs in peripheral blood lymphocytes (mean 1.61 +/- 0.76 DSBs/Gy per 200 MBp, range 0.63- 4.08), which were not correlated. Multivariate analysis showed a correlation (P < 0.008) between late toxicity and higher prescribed protocol dose (81.6 Gy). Analysis of the 29 patients referred to 81.6 Gy revealed significantly (P < 0.031) more frequent late subcutaneous toxicity in those with intrinsic sensitivity to radiation-induced DNA DSBs of >1.69 DSBs/Gy per DNA unit. Our demonstration of a relationship between the sensitivity of in vitro-irradiated peripheral blood lymphocytes and the risk of developing late toxic effects opens up the possibility of predicting normal tissue response to radiation in individual patients, at least in high-dose non-conventional radiation therapy regimens.

Pattern of care for schizophrenia patients in Granada (Spain): a case register study.

AIMS: This study sets out to explore the use flow of mental health services by a cohort of patients with schizophrenia located in Granada (Spain). METHODS: All cases (N = 844) included in the analysis were users of the community mental healthcare public service provided in the area. The Markov chain model was used to calculate the probability of transition from one type of contact with mental health services resources to another type of contact in the next month, over a three-year follow-up. RESULTS: For a given one-month period, for each level of service contact, most patients continued to use the same level of care. CONCLUSIONS: Our results can be interpreted as a reflection of adequate continuity of mental health care provided by the Andalusian community service.

Influence of HLA class I, HLA class II and KIRs on vertical transmission and chronicity of hepatitis C virus in children.

BACKGROUND & AIM: There is evidence that maternal viral load of HCV during delivery influences the risk for Mother-to-child transmission (MTCT), but this does not explain all cases. We study the role of the immunogenetic profile (HLA, KIRs and KIR-ligand binding) of mothers and children in HCV-MTCT and in chronicity in the children. METHODOLOGY: 79 HCV-RNA (+) mothers and their 98 children were included. 24 children were infected, becoming chronic in 8 cases and clearing in 16. HLA-class-I and II and KIRs were determined by Luminex. RESULTS: MTCT study: The presence of HLA-C1-ligand in mothers and/or their children reduces the risk of transmission (mothers: Pc = 0.011, children: P = 0.033), whereas the presence of HLA-C2C2-ligand in mothers increases it (Pc = 0.011). In children KIR2DL3-HLA-C1 is a protector factor (Pc = 0.011). Chronicity in children study: Maternal DQA1*01 allele (Pc = 0.027), KIR2DS1 (Pc = 0.011) or KIR3DS1 (Pc = 0.011) favours chronicity in the child. The presence of the DQB1*03 allele (Pc = 0.027) and KIR2DS3 (P = 0.056) in the child and homozygosity for KIR3DL1/3DL1 (Pc = 0.011) and for the HLA-Bw4/Bw4 ligand (P = 0.027) is associated with viral clearance, whereas the presence of HLA-Bw6 ligand (P = 0.027), the binding of KIR3DS1-HLA-Bw4 (P = 0.037) and heterozygosity for KIR3DL1/3DS1 (Pc = 0.011) favour viral chronicity. Mother/child allele matching: In the joint HLA analysis, matching was greater between mothers and children with chronic infection vs those who had cleared the virus (67%±4.1 vs 57%±1.2, P = 0.003). CONCLUSIONS: The HLA-C1 ligand in the mother is related to MTCT, while several genetic factors of the mother or child are involved in the chronification or clearance of infection in the child. Matching allelic data is considered to be an indicator of HCV chronicity in the child and can be used as a potential prognostic test. This implies that NK cells may play a previously undocumented role in protecting against MTCT and that both NK cell immunity and adaptive T-cell responses may influence viral clearance in infected children.

Activity of tigecycline against clinical isolates of Staphylococcus aureus and extended-spectrum beta-lactamase-producing Escherichia coli in Granada, Spain.

We evaluated the in vitro activity of tigecycline using the Etest and disk diffusion method according to Clinical and Laboratory Standards Institute guidelines against clinical isolates of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) as well as for CTX-M-9 extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and SHV ESBL-producing E. coli. All isolates were susceptible to tigecycline according to US Food and Drug Administration cut-off points. There were no differences in the activity of tigecycline between MSSA and MRSA isolates or between the presence of either type of ESBL. For each type of microorganism studied, we established the equation relating the minimum inhibitory concentration to the diameter of the zone of inhibition.

Handedness and gender influence blood pressure in young healthy men and women: A pilot study.

OBJECTIVE: The type and level of sex steroids influence blood pressure (BP). It has been suggested that functional brain asymmetries may be influenced by sex hormones. In addition, there are inter-arm differences in BP not yet related with handedness. In this study, we hypothesize a possible association between sex hormones, handedness, and inter-arm differences in blood pressure. METHODS: To analyze this hypothesis, we measured BP in the left and right arm of the left and right handed adult young men and women in menstrual and ovulatory phase and calculated their mean arterial pressure (MAP). RESULTS: Significant differences depending on sex, arm, handedness or phase of the cycle were observed. MAP was mostly higher in men than in women. Remarkably, in women, the highest levels were observed in the left handed in menstrual phase. Interestingly, the level of handedness correlated negatively with MAP measured in the left arm of right-handed women in the ovulatory phase but positively with the MAP measured in the right arm of right-handed women in the menstrual phase. CONCLUSIONS: These results may reflect an asymmetrical modulatory influence of sex hormones in BP control.

Contribution of endothelium derived relaxing factors to acetylcholine induced vasodilatation in the rat kidney.

OBJECTIVE: The aim was to evaluate the contribution of nitric oxide (NO) and endothelium derived hyperpolarising factor (EDHF) to the endothelium dependent, acetylcholine induced vasodilatation in isolated perfused rat kidney. METHODS: The renal response to acetylcholine was compared in phenylephrine preconstricted renal vasculature under basal conditions and after the infusion of N omega-nitro-L-arginine (L-NAME), an inhibitor of NO synthesis, and tetraethylammonium, a non-specific blocker of potassium channels that inhibits acetylcholine induced hyperpolarisation. These inhibitors were given alone and together. In another experiment, the renal response to acetylcholine was compared when the vasculature was preconstricted with phenylephrine or with 40 and 80 mM KCl under basal conditions and after the infusion of L-NAME. All experiments were done in the presence of indomethacin. RESULTS: Inhibition of NO generation with L-NAME reduced the vasodilator responses to acetylcholine by approximately 50%, and enhanced the response to sodium nitroprusside in the isolated perfused kidney preconstricted with phenylephrine. Infusion of tetraethylammonium also decreased the response to acetylcholine by approximately 50% and increased vasodilatation responses to sodium nitroprusside. The simultaneous administration of both inhibitors (L-NAME and tetraethylammonium) had a summational effect which almost completely suppressed acetylcholine induced vasodilatation. Increasing concentrations of extracellular potassium produced a dose related decrease in acetylcholine induced vasodilatation. These attenuated responses were almost abolished after the infusion of L-NAME. CONCLUSIONS: Our results suggest that the vasodilator response to acetylcholine in isolated perfused rat kidneys is subserved by EDHF and nitric oxide, both endothelium derived mediators participating to a similar extent.

Serum pyroglutamyl aminopeptidase activity: a promising novel biomarker candidate for liver cirrhosis.

OBJECTIVE: As a reflect of tissue damage, serum aminopeptidases have been proposed as biomarkers of various diseases. In order to search new serologic markers for liver cirrhosis we conducted a preliminary study in which we analyzed a broad range of aminopeptidase activities in serum of controls and patients diagnosed with pancreatitis, hepatitis, and liver cirrhosis without distinction among the etiological type or the degree of severity of each condition. METHODS: Alanyl-, arginyl-, glutamyl-, cystinyl- pyroglutamyl-, and aspartyl-aminopeptidase activities were analyzed fluorometrically, using aminoacyl-ß-naphthylamides as substrates. In addition, various parameters, such as alanine transaminase, aspartate transaminase, alkaline phosphatase, total bilirubin, direct bilirubin, and gamma glutamyl transpeptidase were assayed as routine laboratory test for liver function. RESULTS: Compared with control group, alanyl- and arginyl-aminopeptidase activities increased nonspecifically in pancreatitis, hepatitis and liver cirrhosis, glutamyl- and cystinyl-aminopeptidases did not differ between groups and pyroglutamyl-aminopeptidase demonstrated that while pancreatitis and hepatitis did not differ between them and with controls, this activity decreased selectively in liver cirrhosis compared with all the rest of groups (p<0.001 vs. control and p<0.01 vs. pancreatitis and hepatitis). Aspartyl-aminopeptidase also decreased significantly (p<0.05) in liver cirrhosis compared with controls. Routine parameters for liver function test increased, as expected, in the three pathologies analyzed. CONCLUSIONS: Despite the heterogeneous composition of the three patient groups, the specific reduction of the levels of pyroglutamyl-aminopeptidase activity in serum of liver cirrhosis patients might be considered as a potential candidate to be included in a combination of markers for the diagnosis of this disease.

Therapeutic benefit of melatonin in refractory central serous chorioretinopathy.

PURPOSE: To evaluate the efficacy and safety of melatonin for the treatment of chronic central serous chorioretinopathy (CSCR). METHODS: Prospective comparative case series. A total of 13 patients with chronic CSCR were treated for 1 month: 8 patients were treated orally with 3 mg melatonin t.i.d., and 5 with placebo. All patients had 20/40 or worse Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity (BCVA) in the affected eye or presented an incapacitating scotoma. Most of the patients had previous failed treatments for their condition. Observational procedures included ETDRS BCVA, and complete ophthalmic examination. Optical coherence tomography (OCT) was performed at day 1 and week 4. Fluorescein angiography was performed at baseline only for diagnostic purposes. Data were subjected to two-sample t-test statistical analysis. P-values of <0.05 were considered statistically significant. RESULTS: At 1-month follow-up, BCVA significantly improved in 87.5% of patients treated with melatonin (7 of 8 patients, P<0.05). All patients showed a mean significant reduction (P<0.01) of central macular thickness (CMT) when compared with the baseline, with 3 patients (37.5%) exhibiting complete resolution of subretinal fluid at 1-month follow-up. No significant side effects were observed. No changes in BCVA or CMT were noted in the control group. CONCLUSIONS: These results suggest that melatonin is safe, well tolerated, and effective in the treatment of chronic CSCR, as it significantly improved BCVA and CMT in patients with this pathology. Further evaluations with longer follow-up and a larger patient population are desirable.

Foveal hemorrhage in an immunocompetent patient with visceral leishmaniasis.

OBJECTIVE: To report a case of foveal and macular intraretinal hemorrhages in an immunocompetent male patient with visceral leishmaniasis. CASE REPORT: An immunocompetent, 42 year-old male, presented with progressive visual loss and metamorphopsia in his right eye. The fundus examination showed a foveal round yellow lesion and intraretinal hemorrhages in the macula. The patient was hospitalized with fever, anorexia, weight loss, hepatosplenomegaly, and progressive anemia. Laboratory studies were conducted and a positive test for leishmaniasis and hepatitis A was reported. Treatment was begun with amphotericin B 50mg/day up to a total dose of 1400mg. CONCLUSION: Bilateral retinal hemorrhages in an endemic country could suggest the diagnosis of visceral leishmaniasis.

Relation between vitamin D insufficiency, bone density, and bone metabolism in healthy postmenopausal women.

Although only few postmenopausal women exhibit biochemical signs of hypovitaminosis D, vitamin D insufficiency has been shown to have adverse effects on bone metabolism and could be an important risk factor for osteoporosis and fracture. We determined serum levels of 25-hydroxyvitamin D [25(OH)D], intact parathyroid hormone (iPTH), bone turnover markers, dietary calcium intake, and bone mineral density (BMD; measured by dual X-ray absorptiometry) in 161 consecutive ambulatory women, healthy except for osteoporosis, referred to a bone metabolic unit. The prevalence of vitamin D insufficiency [25(OH)D < or = 15 ng/ml] was 39.1%. 25(OH)D was lower in the osteoporotic subjects (15.7 +/- 5.3 ng/ml vs. 21.8 +/- 9.7 ng/ml; p < 0.001). After controlling for all other variables, lumbar spine (LS) BMD was found to be significantly associated with 25(OH)D, body mass index (BMI), and years after menopause (YSM) (R2 = 0.253; p < 0.001). For femoral neck (FN), significant independent predictors of BMD were YSM, BMI, iPTH, and 25(OH)D (R2 = 0.368; p < 0.001). The probability of meeting osteoporosis densitometric criteria was higher in the vitamin D insufficiency group (odds ratio [OR], 4.17, 1.83-9.48) after adjusting by YSM, BMI, iPTH, and dietary calcium intake. Our study shows that vitamin D insufficiency in an otherwise healthy postmenopausal population is a common risk factor for osteoporosis associated with increased bone remodeling and low bone mass.

Antiresorptive therapy in hyperthyroid patients: longitudinal changes in bone and mineral metabolism.

The effect of antiresorptive therapy with nasal calcitonin (CT) in recently diagnosed hyperthyroid patients on conventional medical therapy as well as the evolution of bone metabolism were assessed. Forty-five patients with recent-onset hyperthyroidism (<12 weeks) were sex and menopause stratified and randomly allocated to treatment with carbimazole (Neotomizol), carbimazole plus low dose CT (Calsynar; 100 IU/day, 2 days/week), or carbimazole plus high dose CT (Calsynar; 100 IU/day, 14 days/month). Bone mineral density was measured by dual x-ray absorptiometry in lumbar spine, femoral neck, and Ward's triangle at 0, 9, and 18 months of treatment. We also determined free T4, free T3, TSH, osteocalcin, total and bone alkaline phosphatases, tartrate-resistant acid phosphatase, type I collagen C telopeptide, and urinary hydroxyproline every 3 months of follow-up. No significant difference was observed among treatments. A euthyroid state was attained at 3 months. Bone mass increased significantly at the 9 month evaluation (P < 0.05), with a 5-10% net gain during follow-up. Nevertheless, final bone mass was 4-8% smaller than expected. Bone formation markers were increased at 0 and 3 months, with reductions at 6-9 months; resorption bone markers showed a significant reduction at the 3 month evaluation. These results indicate that the euthyroid state partially reduces hyperthyroidism-associated osteopenia, with a bone mass recovery period during the 6-9 early months of effective treatment. This recovery phase is characterized by raised bone formation markers and reduced bone resorption markers. The treatment with nasal CT at the doses assayed has no additional effect over that of attainment of the euthyroid state.

Insulin resistance in patients with a recent diagnosis of coronary artery disease.

OBJECTIVE: To elucidate whether insulin resistance is present in coronary artery disease (CAD) at diagnosis and to study its relationship with other known cardiovascular risk factors. METHODS: We evaluated the incidence of insulin resistance in 40 newly diagnosed CAD patients. Fifteen healthy subjects were used as a control group. The patients and controls had no previous history of metabolic disorders, and were not being administered any medication that might have affected their insulin sensitivity. Immediately after diagnosis of CAD, a standard 75 g oral glucose-tolerance test (OGTT) and an insulin suppression test (IST) were performed on separate days. The IST consisted of a constant infusion of glucose, insulin and somatostatin for 150 min; insulin resistance was estimated by determining the steady-state plasma glucose (SSPG) concentrations during the last 60 min of the test. The insulin sensitivity index (ISI) was calculated by the formula ISI = (glucose infusion rate/SSPG]x10(3). RESULTS: Insulin resistance, defined by an ISI below the normal range derived from the control group, was present in 82.5% of the CAD patients. As a group, the patients with CAD displayed lower ISI (means +/- SD:29.23 +/- 11.23 versus 50.33 +/- 9.37 dl/kg per min, P < 0.001) than did controls. Serum triglycerides and uric acid were higher and high-density lipoprotein cholesterol levels were lower in patients than they were in controls. No differences were observed in fasting plasma insulin, glucose, total and low-density lipoprotein cholesterol concentration. An abnormal OGTT result was observed in 27 patients. The ISI was low in 88.8% of the patients with an abnormal OGTT result and in 69% of the 13 patients with a normal OGTT result. CONCLUSIONS: Insulin resistance and even impaired glucose tolerance are common findings in CAD at diagnosis. The changes in the lipid profile and in uric acid levels paralleled the changes in insulin sensitivity. These results suggest that insulin resistance might play a role in the development of coronary atherosclerosis and that its early diagnosis might be important in the prophylaxis of CAD.

Hypoxia inducible factor-1alpha is increased in ischemic retina: temporal and spatial correlation with VEGF expression.

PURPOSE: Hypoxia inducible factor-1 (HIF-1) is a transcription factor composed of HIF-1alpha and HIF-1beta subunits. HIF-1 transactivates multiple genes whose products play key roles in oxygen homeostasis, including vascular endothelial growth factor (VEGF). This study was designed to determine whether HIF-1 levels are increased in ischemic retina and whether there is a correlation with increased expression of VEGF. METHODS: C57BL/6J mice were killed at time points that span retinal vascular development (PO to adult), or on postnatal day (P) 7 they were placed in a 75% oxygen environment for 5 days and then removed to room air and killed after 0, 2, or 6, or 24 hours and 5 or 14 days. Eyes were frozen, and retinas were isolated and used for immunoblot analysis, or eyes were sectioned for immunohisto chemical staining for HIF-1alpha or HIF-1beta, or for in situ hybridization for VEGF. RESULTS: Immunoblots of retinal lysates showed low levels of HIF-1alpha at PO that were markedly increased at P4, remained high throughout the period of retinal vascular development and then decreased to an intermediate level in adults. HIF-1beta levels were relatively constant at all time points. In mice with oxygen-induced ischemic retinopathy, HIF-1alpha levels were increased in the retina. The peak of increase occurred at 2 hours, and levels returned to baseline by 24 hours. Immunohistochemistry showed increased staining for HIF-1alpha throughout the hypoxic inner retina, but not in the normoxic outer retina. There was no modulation of HIF-1beta levels. There was constitutive expression of VEGF mRNA in the inner nuclear layer that was increased 6 hours after the onset of hypoxia and remained elevated for several days. CONCLUSIONS: There are increased levels of HIF-1alpha in ischemic retina that show temporal and spatial correlation with increased expression of VEGF. These findings are consistent with the hypothesis that HIF-1 plays a role in upregulation of VEGF in ischemic retina.

Upregulation of vascular endothelial growth factor in ischemic and non-ischemic human and experimental retinal disease.

Vascular endothelial growth factor (VEGF) is induced by hypoxia and it has been implicated in the development of iris and retinal neovascularization (NV) in ischemic retinopathies in which it has been suggested that Muller cells are responsible for increased VEGF production. VEGF, however, is also known to be a potent mediator of vascular permeability in other tissues and may perform this function in retina. Immunohistochemical staining for VEGF was performed on a variety of human and experimental ischemic and non-ischemic ocular disorders in which blood retinal barrier (BRB) breakdown is known to occur to determine if there is an upregulation of VEGF in these conditions. We found increased VEGF immunoreactivity in ganglion cells of rats with oxygen-induced ischemic retinopathy and in ganglion cells, the inner plexiform layer, and some cells in the inner nuclear layer of rats with experimental autoimmune uveoretinitis (EAU), in which there was no identifiable ischemia or NV. In rats with EAU, VEGF staining intensity increased from 8 to 11 days after immunization, coincident with BRB failure. These results were confirmed using two distinct anti-VEGF antibodies and by immunoblot and the immunohistochemical staining was eliminated by pre-incubating the antibodies with VEGF peptide. VEGF staining was also increased in the retina and iris of patients with ischemic retinopathies, such as diabetic retinopathy and retinal vascular occlusive disease, and in patients with disorders in which retinal ischemia does not play a major role, such as aphakic/ pseudophakic cystoid macular edema, retinoblastoma, ocular inflammatory disease or infection, and choroidal melanoma. VEGF was primarily localized within retinal neurons and retinal pigmented epithelial cells in these cases. In addition or in association with its role of inducing NV, VEGF may contribute to BRB breakdown in a variety of ocular disorders and blockage of VEGF signaling may help to reduce some types of macular edema.

Pyroglutamyl peptidase I levels and their left-right distribution in the rat retina and hypothalamus are influenced by light-dark conditions.

To evaluate the effects of light and darkness on pyroglutamyl peptidase I activity (pGluPI) and its left-right distribution, pGluPI was measured bilaterally in the retina and hypothalamus under selected light-dark schedules. Rats under a 12 h light-dark cycle were divided into four experimental groups. After the end of the 12 h dark period, the animals were kept two additional hours in darkness (group 1), or light (group 2). After the end of the 12 h light period, the animals were kept two additional hours in darkness (group 3), or light (group 4). Experiments were done in light or darkness depending on the 2 h period. In the retina, a previous 12 h light period led to higher values of enzyme activity than dark periods. Left-right predominance, however, depended on the previous 2 h period: the light period led to left predominance, whereas right predominance was found after the 2 h dark period. In the hypothalamus, a left predominance was found only in group 3. These results demonstrate that environmental light conditions influence pGluPI activity in the rat retina and hypothalamus.