The sea urchin embryo, an invertebrate model for mammalian developmental neurotoxicity, reveals multiple neurotransmitter mechanisms for effects of chlorpyrifos: therapeutic interventions and a comparison with the monoamine depleter, reserpine

Lower organisms show promise for the screening of neurotoxicants that might target mammalian brain development. Sea urchins use neurotransmitters as embryonic growth regulatory signals, so that adverse effects on neural substrates for mammalian brain development can be studied in this simple organism. We compared the effects of the organophosphate insecticide, chlorpyrifos in sea urchin embryos with those of the monoamine depleter, reserpine, so as to investigate multiple neurotransmitter mechanisms involved in developmental toxicity and to evaluate different therapeutic interventions corresponding to each neurotransmitter system. Whereas reserpine interfered with all stages of embryonic development, the effects of chlorpyrifos did not emerge until the mid-blastula stage. After that point, the effects of the two agents were similar. Treatment with membrane permeable analogs of the monoamine neurotransmitters, serotonin and dopamine, prevented the adverse effects of either chlorpyrifos or reserpine, despite the fact that chlorpyrifos works simultaneously through actions on acetylcholine, monoamines and other neurotransmitter pathways. This suggests that different neurotransmitters, converging on the same downstream signaling events, could work together or in parallel to offset the developmental disruption caused by exposure to disparate agents. We tested this hypothesis by evaluating membrane permeable analogs of acetylcholine and cannabinoids, both of which proved effective against chlorpyrifos- or reserpine-induced teratogenesis. Invertebrate test systems can provide both a screening procedure for mammalian neuroteratogenesis and may uncover novel mechanisms underlying developmental vulnerability as well as possible therapeutic approaches to prevent teratogenesis.     

Metallothioneins and heat shock proteins 70 in marine mussels as sensors of environmental pollution in Northern Adriatic Sea

In an attempt to assess the intensity of environmental pollution in industrial zones of Kvarnerian Bay in Northern Adriatic Sea and the reactivity of Mytilus galloprovincialis to these changes, in this study we estimated the concentration of heavy metals at four locations in both sea-sediment and in the mussels. Further we tried to correlate these changes with seasonal variations in environmental temperature, pH and salinity, as well as with the expression of metallothioneins (MTs) and heat shock proteins (HSPs) in the digestive tract of the mussels. Sampling in vivo was performed monthly, during the year 2008, while under the laboratory conditions the reactivity of acclimated mussels were tested to increasing concentrations of CdCl₂ and to thermal stress. The data have shown that the induction of MTs and HSP isoforms of the 70-kDa size class were highly affected by model agents treatment including contamination of sea-sediment by Pb, Hg and Cd, implying that these stress proteins might be power biomarkers of marine pollution.     

Comparison of survival between diabetic and non-diabetic patients on maintenance hemodialysis: a single-centre experience

We analyzed survival rates of 144 prevalent patients on maintenance hemodialysis from 1998 to 2003 at the Department of Nephrology and Dialysis, Rijeka University Hospital, Rijeka, Croatia, and evaluated risk factors predicting their survival. Included were only end-stage renal disease (ESRD) patients on maintenance hemodialysis treatment dialysed more than 6 months before entering the study and who were clinically stable. The patients were randomised in two groups according to the presence or absence of diabetic nephropathy as the cause of ESRD and followed-up. The patient's death as outcome measure was recorded. The survival rates were estimated by the Kaplan-Meier method. The major causes of death were cardiovascular disease in 40 (60.6%) patients. An acute myocardial infarction in 15 (22.7%) patients was the major single cause of death. We found a significantly lower survival of diabetic patients than non-diabetic patients (P=0.0013). The most important predictors of death among diabetic patients on maintenance hemodialysis were hyperglycaemia (P<0.001), ischemic heart disease (P=0.004), hypercholesterolemia (P=0.013), and low delivered dialysis dose (P=0.013). The survival of diabetic patients undergoing hemodialysis was much worse than survival of non-diabetic patients. The cardiovascular disease remained the major cause of death in both groups. Early detection of pre-existing cardiovascular risk factors and diseases, and treatment of infections leading to sepsis, are of great importance, as they may influence the survival rates. Intensive management of diabetic patients is essential.     

Effect of surgical incision on pain and respiratory function after abdominal surgery: a randomized clinical trial

BACKGROUND/AIMS: The aim of the present study was to assess the severity of respiratory disturbances occurring after abdominal surgery and to identify surgical incisions that entail the least respiratory complications and postoperative pain. METHODOLOGY: A total of 105 patients divided into two groups were included in this randomized clinical trial. Seventy-five patients in the first group underwent upper abdominal surgery, and were operated on by use of vertical, oblique, transverse and elliptic incision. The remaining 30 patients in the second group were submitted to low abdominal surgery by use of vertical and oblique incision. Arterial blood gases and pulmonary shunt development were determined at 12 h preoperatively, and at 6 h, 72 h and 144 h postoperatively. During the postoperative course, VAS-pain score and use of tramadol were observed according to the type of surgical incision employed. RESULTS: Most severe respiratory disturbances in terms of PaO2 decrease, activating compensatory hyperventilation, pulmonary shunt increase, the highest VAS-pain score and consumption of tramadol were induced by the following upper abdominal incisions: transversal laparotomy according to Orr, elliptic periumbilical laparotomy, upper midline laparotomy, transrectal laparotomy and subcostal laparotomy. In the group of low abdominal surgery (low midline laparotomy and inguinal incision) consumption of tramadol was statistically significantly lower, but no statistically significant differences were recorded between the baseline preoperative and postoperative values of PaO2, PaCO2 and pulmonary shunt. CONCLUSIONS: All low abdominal incisions were found to entail statistically significantly less respiratory disturbances, lower VAS-pain score and lower tramadol use when compared to upper abdominal incisions. The upper abdominal incisions observed caused substantial respiratory disturbances including hypoxia, hyperventilation and pulmonary shunt increase.     

Dramatic increase in naive T cell turnover is linked to loss of naive T cells from old primates

The loss of naïve T cells is a hallmark of immune aging. Although thymic involution is a primary driver of this naïve T cell loss, less is known about the contribution of other mechanisms to the depletion of naïve T cells in aging primates. We examined the role of homeostatic cycling and proliferative expansion in different T cell subsets of aging rhesus macaques (RM). BrdU incorporation and the expression of the G₁-M marker Ki-67 were elevated in peripheral naïve CD4 and even more markedly in the naïve CD8 T cells of old, but not young adult, RM. Proliferating naïve cells did not accumulate in old animals. Rather, the relative size of the naïve CD8 T cell compartment correlated inversely to its proliferation rate. Likewise, T cell receptor diversity decreased in individuals with elevated naïve CD8 T cell proliferation. This apparent contradiction was explained by a significant increase in turnover concomitant with the naïve pool loss. The turnover increased exponentially when the naïve CD8 T cell pool decreased below 4% of total blood CD8 cells. These results link the shrinking naïve T cell pool with a dramatic increase in homeostatic turnover, which has the potential to exacerbate the progressive exhaustion of the naïve pool and constrict the T cell repertoire. Thus, homeostatic T cell proliferation exhibits temporal antagonistic pleiotropy, being beneficial to T cell maintenance in adulthood but detrimental to the long-term T cell maintenance in aging individuals.     

Signaling status of IgG B cell receptor (IgG BCR) is indicative for an activated state of circulating B cells in multiple myeloma

Circulating post-switch B cells have been proposed as proliferative and disseminating progenitors in multiple myeloma. It is unclear whether the class-switched antigen receptor expressed at the surface of these cells plays a role in their expansion. In this work, the signaling status of IgG B cell receptor (BCR) isolated from the lysates of peripheral blood lymphocytes of 32 patients with IgG multiple myeloma, at the time of diagnosis, was investigated by examining whether phosphorylation of BCR Igalpha and Igbeta signal transducer factors (co-receptors) or other signaling molecules was abnormal in these cells when compared with healthy controls. In IgG BCR of normal controls, weak phosphorylation of 56 and 61 kDa Src kinase-related proteins and unphosphorylated co-receptors were found. In myeloma, p56 and p61 kDa proteins, co-receptors, and other IgG BCR-associated proteins from the signal cascade were phosphorylated. Myeloma patients can be classified into subgroups by IgG BCR phosphorylation profiles which characteristically coordinated with the level of IgG paraprotein in serum and the stage of disease. There was a correlative trend between the extent of phosphorylation reduction and advanced stage of disease. Reduced phosphorylation was more pronounced with advanced stages of multiple myeloma.     

Sympathetic neural responses to coronary occlusion during balloon angioplasty

OBJECTIVE: The sympathetic nervous system is a key modulator of prognosis and outcome in cardiac ischaemia and infarction. The effects of acute cardiac ischaemia on sympathetic neural traffic in humans are unknown. We tested the hypothesis that angioplasty, and associated transient myocardial ischaemia, elicits changes in neural circulatory control, including direct intraneural measures of sympathetic traffic. METHODS: We measured muscle sympathetic nerve activity (MSNA), blood pressure and heart rate in 12 patients (11 men, one woman) undergoing clinically indicated elective coronary angioplasty of the left anterior descending (n = 7) or circumflex (n = 5) coronary artery. Baseline data were obtained for 2 min before occlusion. Each balloon inflation was designed to last up to 120 s. RESULTS: Coronary occlusion had no significant effect on blood pressure or heart rate. In contrast, occlusion resulted in a significant increase in MSNA, in 10 of the 12 patients, and in all seven of those patients undergoing angioplasty of the left anterior descending artery. The group mean increase in MSNA during occlusion was 36 +/- 11% (P = 0.008 versus preocclusion). MSNA increased within 60 s of occlusion (129 +/- 12% of baseline; n = 12; P = 0.04), and increased further during the next 60 s to 141 +/- 12% of baseline levels (n = 10; P < 0.001). Increases in MSNA were similar in patients with and without significant chest pain (39 +/- 9% versus 34 +/- 13%, respectively; P = 0.84). CONCLUSION: Acute coronary occlusion during angioplasty increases central sympathetic outflow, but there is no systematic change in heart rate. The increase in sympathetic nerve traffic cannot be explained by blood pressure changes or occlusion-related chest pain.