Effects of estrogenic (o,p'-DDT; octylphenol) and anti-androgenic (p,p'-DDE) chemicals on indicators of endocrine status in juvenile male summer flounder (Paralichthys dentatus)

Laboratory experiments were conducted with male summer flounder to assess the value of selected measures of endocrine status in fish as indicators of exposure to endocrine-disrupting contaminants. Effects of 1,1,1-trichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl) ethane (o,p'-DDT), octylphenol and 1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE) on hepatosomatic and gonadosomatic indices, plasma steroid hormone levels, vitellogenin production, and gonadal development were evaluated in laboratory-raised, juvenile male summer flounder. Flounder were injected twice with test chemical in a coconut oil carrier. Each chemical was tested at three different concentrations. Estrogenic (o,p'-DDT; octylphenol) and anti-androgenic (p,p'-DDE) chemicals were evaluated alone and in combination (octylphenol plus o,p'-DDT or p,p'-DDE). Additionally, some fish were treated with the natural ligand for the estrogen receptor, 17beta-estradiol. Blood and tissues from different fish in each treatment were sampled 4, 6 and 8 weeks after the first injection. Fish exposed to a combination of o,p'-DDT plus octylphenol were also sampled after 15 weeks. In all cases, responses of fish exposed to a test chemical were compared to control fish sampled at the same time. The following significant differences, relative to controls, were observed in at least one sampling time or at least one concentration of chemical. 17beta-Estradiol-treated flounder exhibited decreased gonadosomatic index (GSI), altered hepatosomatic index (HSI), elevated plasma estradiol, reduced plasma testosterone, and high levels of plasma vitellogenin. Fish treated with o,p'-DDT showed lower GSI, no change in HSI or plasma estradiol, depression of plasma testosterone, and induction of vitellogenesis. Octylphenol treatment resulted in lower GSI, no change in HSI, initially increased plasma estradiol and decreased testosterone, and no vitellogenin production. p,p'-DDE treatment did not significantly alter any indicator relative to controls. In experiments using combinations of chemicals, flounder receiving o,p'-DDT plus octylphenol had lower GSI after 8 weeks and elevated plasma estradiol after 15 weeks exposure. Fish treated with p,p'-DDE plus octylphenol for 8 weeks exhibited a significantly lower GSI. Overall, lower GSI and plasma testosterone levels, relative to controls, were consistent indicators of exposure to estrogenic chemicals in juvenile male flounder. No indicators were found that would identify exposure to the mammalian anti-androgen p,p'-DDE.     

Stored retinoids in populations of the estuarine fish Fundulus heteroclitus indigenous to PCB-contaminated and reference sites

Concentrations of retinoids, derivatives of vitamin A, were measured in populations of the nonmigratory estuarine fish Fundulus heteroclitus, indigenous to a reference site and a site highly contaminated with polychlorinated biphenyls (PCBs) to address the hypothesis that contaminant exposure causes depletion of stored retinoids in native fish populations. To assess differences related to chemical exposure, as well as season and diet, hepatic retinoid analyses were conducted using fish collected early and late in the natural spawning season and after laboratory holding. Though hepatic retinoid composition was generally similar among groups, hepatic retinoid concentrations differed. Laboratory-held fish had higher hepatic retinyl ester concentrations than field-collected fish. Among field-collected fish, those collected early in the spawning season had higher hepatic retinyl ester concentrations than those collected later in the spawning season. Although there was no evidence of the dramatic retinoid depletions that have been reported in highly exposed populations of other fish species, hepatic retinoid stores were consistently lower in F. heteroclitus indigenous to the highly PCB-contaminated site. These results are consistent with prior findings that fish from this contaminated site are relatively insensitive to some of the toxic effects of PCB exposures, including retinoid depletion. Received: 28 July 2000/Accepted: November 2000     

Relationships among total lipid, lipid classes, and polychlorinated biphenyl concentrations in two indigenous populations of ribbed mussels (Geukensia demissa) over an annual cycle

Two indigenous ribbed mussel (Geukensia demissa) populations were sampled approximately every four weeks during 1997 to investigate the relationships among concentrations of total lipid, lipid classes, and polychlorinated biphenyls (PCBs). One population was located in a highly contaminated area near a Superfund site (New Bedford Harbor, MA, USA), while the other population was located at a relatively clean site (West Island, Fairhaven, MA, USA). Mussel tissue total PCB concentrations (quantified as the sum of 18 congeners) from the contaminated site were two orders of magnitude greater than those at the clean site. Total lipid and triacylglycerol (TG) also were higher at the contaminated site. No significant relationship (p > 0.05) was observed between total PCBs and total lipid at either location; however, the correlations at both sites increased when total PCBs were compared with total TG or, to a lesser extent, total nonpolar lipid. Principal component analysis and linear discriminatory analysis indicated that the two mussel populations could be distinguished by the proportions of their lipid classes, particularly the concentration of nonpolar lipids, which consisted mainly of TG. These results suggest that the standard method of normalizing organism PCB concentrations to total lipid may not be appropriate as a routine practice, especially when the organism has a relatively low total lipid content (<6% dry wt in this study).     

Thrombolysis for acute stroke: Is it for everyone?

To date, there is only one US Food and Drug Administration-approved treatment for stroke. Many patients have benefited after receiving rt-PA within 3 hours of acute stroke. Although the risk of hemorrhagic conversion is real, the patients at high risk for this complication are often the same patients most at risk for poor outcome secondary to their ischemic events. In this article, we review the data supporting the use of thrombolytics, both intravenously and intra-arterially, as well as patient selection criteria. Furthermore, we provide a framework for administering rt-PA and discuss the future of thrombolytic therapy.     

Serum Mortalin Correlated with α-Synuclein as Serum Markers in Parkinson’s Disease: A Pilot Study

Mortalin, a mitochondrial chaperone, plays a crucial role in reducing toxicity of Lewy bodies. Earlier studies had reported that Mortalin level gets downregulated in astrocytes and other brain tissue samples in Parkinson’s disease (PD). This study aims to estimate the Mortalin concentration in serum and correlate with α-synuclein (α-Syn) in PD. The concentration of Mortalin and α-Syn in serum samples of 38 PD patients and 33 control group (CG) individuals was quantified by surface plasmon resonance. The receiver operating characteristic curves were plotted to develop it as blood-based protein marker. The expression of Mortalin in serum was validated by western blot. The Mortalin level was found to be declined in PD patients (1.98 ± 0.53 ng/µL) in comparison with CG individuals (3.13 ± 0.48 ng/µL), whereas α-Syn level was found to be elevated in PD patients (38.20 ± 4.22 ng/µL) than CG individuals (34.31 ± 3.23 ng/µL) in serum. The statistical analysis revealed the negative correlation between Mortalin and α-Syn. This preliminary study summarized that Mortalin plays a significant role in PD with negative correlation with α-Syn. This study provides a new paradigm for the development of Mortalin as a potent serum protein marker for diagnosis of PD.     

Current Patterns of Prehospital Trauma Care in Kampala,Uganda and the Feasibility of a Lay-First-Responder Training Program

Background  

Uganda currently has no organized prehospital emergency system. We sought to measure the current burden of injury seen by lay people in Kampala, Uganda and to determine the feasibility of a lay first-responder training program.     

Local RF capacitive hyperthermia: thermal profiles and tumour response

At the Cancer Institute we are using RF capacitive hyperthermia as an adjuvant to radiotherapy and/or chemotherapy in the local control of soft tissue sarcomas. We have studied the influence of bolus conductivity, electrode and phantom sizes on the rate of heating of agar phantoms. We have varied the bolus conductivity by varying the saline concentration in the bolus bags from zero to 2.0 per cent, during heating. We found that the rate of heating of phantoms increases and that of the bolus decreases with the increase in the saline concentration of bolus up to 1 per cent, irrespective of phantom and electrode sizes. However, for a given size of electrodes the rate of heating decreased with the increase in the phantom size. When the diameter and height of the phantom were equal to the diameters of electrodes the rate of heating of the phantom was nearly uniform. However, when the diameter of the phantom was larger than that of electrodes the rate of heating in the radial axis decreased with the increase in the radial distance. On the basis of this data we suggest the use of electrodes larger in size by 1.0-3.0 cm than the size of the tumour, where the size of the anatomical site to be heated is larger than the electrode size to be used. Phantom and clinical data have indicated that the presence of bone in the field of heating can lead to hot spots. Preliminary clinical results have shown that the response of sarcomas to thermo-chemo-radiotherapy was superior to that of either thermo-radiotherapy or radiotherapy alone.