Retinal ganglion cells projecting to the accessory optic system in the rat

The present data identify the distribution and morphological features of a homogeneous group of rat retinal ganglion cells. These cells were labelled after injection of either horseradish peroxidase or a fluorescent tracer, Fast Blue, into the medial terminal nucleus (MTN) of the accessory optic system. After retrograde fluorescent labelling, MTN-projecting retinal ganglion cells were intracellularly injected with Lucifer Yellow to reveal their complete dendritic morphology. There were on average 1,750 MTN-projecting cells fairly evenly distributed over the entire retinal ganglion cell layer. Their density ranged from 40-49 cells/mm2 in superior retina to 10-19 cells/mm2 towards the peripheral regions of both inferior and superior retina. The area of highest density formed a nasal-temporal band suggestive of a visual streak. Soma diameters ranged from 8.7 to 14.5 micron centrally and from 9.9 to 17.1 microns peripherally. Maximal dendritic field diameter ranged from 431 to 644 micron and averaged 516 micron with no obvious eccentricity dependence. The majority of MTN-projecting cells were bistratified. Dendrites stratified predominantly in the inner sublamina of the inner plexiform layer (IPL) with a varying number of branches from the remaining dendrites contained within the outer IPL, both strata presumably corresponding to the electrophysiologically determined on-off dichotomy. Cells projecting to the MTN were characterised by higher-order dendritic branching patterns that resulted in a dense dendritic tree with minor dendritic overlap. The slender dendrites had a beaded appearance and displayed spiny protrusions. The dendritic coverage of 5-6, stratification pattern, and overall morphological appearance of rat MTN-projecting cells renders them suitable candidates for on-direction--selective cells shown electrophysiologically to be linked with the MTN of the accessory optic system.     

Immunoadsorption for coagulation factor inhibitors

Inhibitors to coagulation factors are among the most difficult problems in the management of coagulation disorders. Most presently available therapy does not assure hemostasis. An extracorporeal immunoadsorption system, which selectively binds IgG, was used to lower inhibitor levels in eight patients on 10 occasions. In this system, separated plasma is delivered to two staphylococcal protein A-Sepharose columns, which are coupled to an elution monitor. Columns are eluted sequentially and regenerated to maximize IgG removal. Successful removal of the inhibitor was accomplished in all six hemophiliacs on seven occasions, as well as in a patient with acquired von Willebrand disease. All patients whose inhibitors were lowered to less than 10 Bethesda units achieved measurable factor levels when factor concentrate replacement was given. Immunoadsorption facilitates efficient removal of inhibitors, which allows factor replacement therapy.     

A double-blind provocative study chocolate as a trigger of headache

A provocative double blind study of headache was performed using chocolate as the active agent and carob as the placebo. The chocolate and carob samples were formulated to duplicate products used in an earlier study (1) in which strong differential effects between the ability of chocolate and carob to trigger headache in migraine were shown. Sixty-three women with chronic headache (50% migraine, 37.5% tension-type, 12.5% combined migraine and tension-type) participated in the study. After 2 weeks of following a diet that restricted vasoactive amine-rich foods, each subject underwent double-blinded provocative trials with two samples of chocolate and two of carob presented in random order. Diaries were maintained by the subjects throughout the study, monitoring diet and headache. The results demonstrated that chocolate was not more likely to provoke headache than was carol in any of the headache diagnostic groups (²(2) 0.36, p =0.83). Interestingly, these results were independent of subjects' beliefs regarding the role of chocolate in the instigation of headache (²(1)=0.73, p =0.39). Headache diagnosis and the concomitant use of additional vasoactive amine-containing foods were also not associated with chocolate acting as a headache trigger. Thus, contrary to the commonly held belief of patients and physicians, chocolate does not appear to play a significant role in triggering headaches in typical migraine, tension-type, or combined headache sufferers.     

The calcium-sensing receptor regulates mammary gland parathyroid hormone-related protein production and calcium transport

The transfer of calcium from mother to milk during lactation is poorly understood. In this report, we demonstrate that parathyroid hormone-related protein (PTHrP) production and calcium transport in mammary epithelial cells are regulated by extracellular calcium acting through the calcium-sensing receptor (CaR). The CaR becomes expressed on mammary epithelial cells at the transition from pregnancy to lactation. Increasing concentrations of calcium, neomycin, and a calcimimetic compound suppress PTHrP secretion by mammary epithelial cells in vitro, whereas in vivo, systemic hypocalcemia increases PTHrP production, an effect that can be prevented by treatment with a calcimimetic. Hypocalcemia also reduces overall milk production and calcium content, while increasing milk osmolality and protein concentrations. The changes in milk calcium content, milk osmolality, and milk protein concentration were mitigated by calcimimetic infusions. Finally, in a three-dimensional culture system that recapitulates the lactating alveolus, activation of the basolateral CaR increases transcellular calcium transport independent of its effect on PTHrP. We conclude that the lactating mammary gland can sense calcium and adjusts its secretion of calcium, PTHrP, and perhaps water in response to changes in extracellular calcium concentration. We believe this defines a homeostatic system that helps to match milk production to the availability of calcium.     

Triclosan: environmental exposure, toxicity and mechanisms of action

Triclosan [5-chloro-2-(2,4-dichlorophenoxy)phenol; TCS] is a broad spectrum antibacterial agent used in personal care, veterinary, industrial and household products. TCS is commonly detected in aquatic ecosystems, as it is only partially removed during the wastewater treatment process. Sorption, biodegradation and photolytic degradation mitigate the availability of TCS to aquatic biota; however the by-products such as methyltriclosan and other chlorinated phenols may be more resistant to degradation and have higher toxicity than the parent compound. The continuous exposure of aquatic organisms to TCS, coupled with its bioaccumulation potential, have led to detectable levels of the antimicrobial in a number of aquatic species. TCS has been also detected in breast milk, urine and plasma, with levels of TCS in the blood correlating with consumer use patterns of the antimicrobial. Mammalian systemic toxicity studies indicate that TCS is neither acutely toxic, mutagenic, carcinogenic, nor a developmental toxicant. Recently, however, concern has been raised over TCS's potential for endocrine disruption, as the antimicrobial has been shown to disrupt thyroid hormone homeostasis and possibly the reproductive axis. Moreover, there is strong evidence that aquatic species such as algae, invertebrates and certain types of fish are much more sensitive to TCS than mammals. TCS is highly toxic to algae and exerts reproductive and developmental effects in some fish. The potential for endocrine disruption and antibiotic cross-resistance highlights the importance of the judicious use of TCS, whereby the use of TCS should be limited to applications where it has been shown to be effective.     

Hantavirus reservoir Oligoryzomys longicaudatus spatial distribution sensitivity to climate change scenarios in Argentine Patagonia

Background  

Oligoryzomys longicaudatus (colilargo) is the rodent responsible for hantavirus pulmonary syndrome (HPS) in Argentine Patagonia. In past decades (1967–1998), trends of precipitation reduction and surface air temperature increase have been observed in western Patagonia. We explore how the potential distribution of the hantavirus reservoir would change under different climate change scenarios based on the observed trends.     

Transfusion medicine during the summer of 2006: lessons learned in northern Israel

In July 2006 a Hizballah attack erupted at the Lebanon-Israel border. Reported here is the experience of the Rambam Health Care Campus--a level I trauma center--during 33 days of warfare. Two hundred ninety-five soldiers and 209 civilians were admitted to the emergency department (ED). Forty-eight wounded soldiers (16%) and 12 civilians (6%) had transfusion. Twenty soldiers and 1 civilian had massive transfusions. The ratio between packed red blood cells and fresh frozen plasma (FFP) used for patients who had massive transfusion was 3:2. In these patients, the median prothrombin time international normalized ratio and partial thromboplastin time increased during the first 2 hours after admission from 1.29 to 1.51 and from 33.6 to 39 seconds, respectively. Twenty patients who had massive transfusion survived. Patients with an injury severity score of at least 16 had a higher need for blood products than others, with a lower severity score, with a mean packed red blood cells unit transfusion of 7 vs 4 (P = .03) and FFP transfusion of 13 vs 1.5 (P = .002), respectively. In conclusion, we observed that early transfusion of FFP to casualties with penetrating wounds requiring massive transfusion is needed to overcome the coagulopathy present. The presence of a transfusion service representative on-site in the ED is recommended to ensure proper identification and labeling of blood samples. Real-time consultations provided by a transfusion medicine physician in the operation theater was also found to be essential.     

Assessing sources of PM2.5 in cities influenced by regional transport

The human health effects of fine particulate matter (PM2.5) have provided impetus for the establishment of new air quality standards or guidelines in many countries. This has led to the need for information on the main sources responsible for PM2.5. In urban locations being impacted by regional-scale transport, source-receptor relationships for PM2.5 are complex and require the application of multiple receptor-based analysis methods to gain a better understanding. This approach is being followed to study the sources of PM2.5 impacting southern Ontario, Canada, and its major city of Toronto. Existing monitoring data in the region around Toronto and within Toronto itself are utilized to estimate that 30-45% of the PM2.5 is from local sources, which implies that 55-70% is transported into the area. In addition, there are locations in the city that can be shown to experience a greater impact from local sources such as motor vehicle traffic. Detailed PM2.5 chemical characterization data were collected in Toronto in order to apply two different multivariate receptor models to determine the main sources of the PM2.5. Both approaches produced similar results, indicating that motor-vehicle-related emissions, most likely of local origin, are directly responsible for about 20% of the PM2.5. Gasoline engine vehicles were found to be a greater overall contributor (13%) compared to diesel vehicles (8%). Secondary PM2.5 from coal-fired power plants continues to be a significant contributor (20-25%) and also played a role in enhancing production of secondary organic carbon mass (15%) on fine particles. Secondary fine particle nitrate was the single most important source (35%), with a large fraction of this likely related to motor vehicle emissions. Independent use of different receptor models helps provide more confidence in the source apportionment, as does comparison of results among complementary receptor-based data analysis approaches.