Rat choroidal pericytes as a target of the autonomic nervous system

Pericytes are contractile cells that surround blood vessels. When contracting, they change the diameter of the vessel and therefore influence blood flow homeostasis; however, mechanisms controlling pericyte action are less well understood. Since blood flow regulation per se is controlled by the autonomic nervous system, the latter might also be involved in pericyte action. Hence, rat choroidal pericytes were analyzed for such a connection by using appropriate markers. Rat choroidal wholemounts and sections were prepared for immunohistochemistry of the pericyte marker chondroitin-sulfate-proteoglycan (NG2) and the pan-neuronal marker PGP9.5 or of tyrosine hydroxylase (TH), vasoactive intestinal polypeptide (VIP) and choline acetyl transferase (ChAT). Additionally, PGP9.5 and TH were analyzed in the choroid of DCX-dsRed2 transgenic rats, displaying red-fluorescent perivascular cells and serving as a putative model for studying pericyte function in vivo. Confocal laser-scanning microscopy revealed NG2-immunoreactive cells and processes surrounding the blood vessels. These NG2-positive cells were not co-localized with PGP9.5 but received close appositions of PGP9.5-, TH-, VIP- and ChAT-immunoreactive boutons and fibers. In the DCX-dsRed2 transgenic rat, PGP9.5 and TH were also densely apposed on the dsRed-positive cells adjacent to blood vessels. These cells were likewise immunoreactive for NG2, suggesting their pericyte identity. In addition to the innervation of vascular smooth muscle cells, the close relationship of PGP9.5 and further sympathetic (TH) and parasympathetic (VIP, ChAT) nerve fibers on NG2-positive pericytes indicated an additional target of the autonomic nervous system for choroidal blood flow regulation. Similar findings in the DCX-dsRed transgenic rat indicate the potential use of this animal model for in vivo experiments revealing the role of pericytes in blood flow regulation.     

A theory of photosensitivity of some lower animals

The two-factor nerve excitation theory is applied to the photoreactions of some lower animals along with the assumption that the threshold itself varies under the action of light, thus behaving formally like a third factor. The dependence of the reaction time upon the intensity of the stimulus is derived and is shown to follow the Bunsen-Roscoe law. The dependence of reaction time upon the time of exposure to light of a fixed intensity is derived and analyzed. The effect of dark adaptation upon the reaction time is analyzed quantitatively. Light adaptation and the effects of termination of exposure after light adaptation are discussed from the standpoint of this theory and the theory is found to be in agreement with observations.     

Die Wirkung des Synthalin A auf das A-Zellensystem des Inselorganes bei der Ratte in den ersten Lebenstagen

Zusammenfassung Nach einer einmaligen Gabe von Synthalin A (10 mg/kg subkutan) an 1–5 Tage alte Ratten tritt an den A-Zellen des Inselorgans keine zytologisch erkennbare Schädigung auf, wie sie bei ausgewachsenen Tieren beschrieben wurde. Schollen-, Blasen- und Trümmerstadien konnten in keinem Falle erzeugt werden. Hingegen wurde an den A-Zellen behandelter Tiere eine einschneidende Verminderung der Mitosefrequenz und eine Schädigung der vorhandenen A-Zellmitosen festgestellt, die als selektiv bezeichnet werden muß, da die B-Zellmitosen und die Teilungsfiguren der exokrinen Zellen in quantitativer und qualitativer Hinsicht intakt sind.Mit Unterstützung der Research Corporation, New York.     

Hydrogen fluoride catalyzed migration of side chain protecting groups onto Fmoc during solid phase peptide synthesis. Characterization by CF-FAB analysis of carboxypeptidase digestions and NMR spectroscopy.

The solid-phase synthesis of the N alpha-Fmoc analog of protein kinase C substrate (PKCS, Lys-Arg-Ala-Lys-Ala-Lys-Thr-Thr-Lys-Lys-Arg) was characterized by low recovery from the resin and the concomitant appearance of four impurities. FAB-MS revealed molecular weights for two of these impurities that corresponded to the desired peptide plus Tos or Bzl. The other two were justified by invoking a CO2 elimination of the Clz protecting group to yield: 1) peptide plus 2-chlorobenzyl (ClBzl) and 2) peptide plus ClBzl and Tos. A CF-FAB analysis of carboxypeptidase digestions allowed observation of peptide cleavage down to an ion corresponding to lysine, Fmoc, and the corresponding protecting group(s). These data revealed that the impurities were not the result of incomplete deprotection but the result of migration of the protecting groups to the N-terminal end of the peptide. NMR experiments were subsequently performed and revealed the exact site of substitution: the meta positions of the N-terminal Fmoc. These impurities are presumed to arise by electrophilic aromatic substitution of the fluorene group during HF treatment. The desired Fmoc analog served as a convenient, albeit low-yielding, intermediate for purification of the highly charged PKCS by preparative self-displacement HPLC.     

Metorchis conjunctus (Cobbold, 1860) infection in wolves (Canis lupus), with pancreatic involvement in two animals

The trematode Metorchis conjunctus (Cobbold, 1860) was found in seven of 211 wolves from Saskatchewan which were examined between 1976 and 1983. The parasite caused cholangiohepatitis with periductular fibrosis in the liver of all the wolves, and chronic inflammation and fibrosis of the pancreas in two animals. The wolves with pancreatic involvement were emaciated. Five of the seven infected wolves were from one local area, and three of these were from a pack known to consume fish.     

CAPTURE-RECAPTURE ANALYSIS FOR ESTIMATING MANATEE REPRODUCTIVE RATES

Modeling the life history of the endangered Florida manatee ( Trichechus manatus latirostris ) is an important step toward understanding its population dynamics and predicting its response to management actions. We developed a multi-state markresighting model for data collected under Pollock's robust design. This model estimates breeding probability conditional on a female's breeding state in the previous year; assumes sighting probability depends on breeding state; and corrects for misclassification of a cow with first-year calf, by estimating conditional sighting probability for the calf. The model is also appropriate for estimating survival and unconditional breeding probabilities when the study area is closed to temporary emigration across years. We applied this model to photo-identification data for the Northwest and Atlantic Coast populations of manatees, for years 1982–2000. With rare exceptions, manatees do not reproduce in two consecutive years. For those without a first-year calf in the previous year, the best-fitting model included constant probabilities of producing a calf for the Northwest (0.43, SE = 0.057) and Atlantic (0.38, SE = 0.045) populations. The approach we present to adjust for misclassification of breeding state could be applicable to a large number of marine mammal populations.