Photoperiod Affects the Ability of Testosterone to Alter Proopiomelanocortin mRNA, but not Luteinizing Hormone-Releasing Hormone mRNA, Levels in Male Sheep

This study tested the hypothesis that photoperiod affects the ability of testosterone to reduce proopiomelanocortin (POMC) mRNA levels in the arcuate nucleus and luteinizing hormone-releasing hormone (LHRH) mRNA levels in both the preoptic area (POA) or medial basal hypothalamus (MBH). Twenty castrated male sheep were assigned to one of four treatment groups (i): short days (SD;
n=5) (ii), short days with testosterone (SD+T; n=5) (iii), long days (LD; n=5), or (iii) long days with testosterone (LD+T; n=5). Blood samples were collected twice weekly for the last 3 weeks of photoperiod treatment and assessed for LH to validate the response to photoperiod. After evaluating LH levels, one animal each from the LD+T and SD+T groups was excluded from the analyses. Mean concentrations of LH were lower (P<0.01) in the LD+T group than in the other treatment groups, which did not differ (P>0.10) from each other. Neither POA nor MBH LHRH mRNA levels were affected (P>0.10) by treatment. Conversely, POMC mRNA levels were suppressed (P<0.01) in the LD+T males compared with the other treatment groups which did not differ (P>0.10) from each other. These observations suggest that photoperiod specific, testosterone-induced alterations in LHRH mRNA levels are not a mechanism whereby testosterone suppresses LHRH release, and that increased beta-endorphin synthesis and release do not mediate testosterone-induced seasonal suppression of LHRH release.     

Isolation and identification of polychlorinated styrenes in Great Lakes fish

Summary Octachlorostyrene was prepared by two independent synthetic routes, and GC retention time data as well as a mass spectrum of the standard were obtained. A comparison of these data with those observed for a component in fish from Lake Huron, Lake Ontario, and the lower Detroit River indicates that octachlorostyrene is present in fish residues from these sources. In addition, mass spectral data indicated the presence of several hepta and hexachlorostyrene isomers in these fish. Further studies should be concerned with quantification of OCS and evaluation of possible sources of these compounds, such as impurities in products produced by exhaustive chlorination or as by-products in the electrolytic production of chlorine.     

Reactivity of locally produced CSF antibodies in patients with neurosyphilis against antigens ofTreponema pallidum

The reactivity and specificity of locally produced cerebrospinal fluid (CSF) antibodies against antigens ofTreponema pallidum were assessed by Western blotting in patients with clinical signs of parenchymal or meningovascular neurosyphilis. All nine patients showed local production of treponeme-specific antibodies in the central nervous system (CNS). In most of the patients serum and CSF antibodies were bound to the same antigens: the common treponemal 48/45 kDa protein and the putative specificT. pallidum protein in the range of 12-14 kDa. In some patients the intensity of staining obtained by CSF antibodies was higher than that derived from serum, indicating locally produced antibodies. In contrast to other more acute inflammatory CNS diseases, no expanded or different antigen binding of the CSF antibodies compared with serum antibodies was found in neurosyphilic patients. The results presented are discussed with regard to the role of the blood-brain barrier in antibody concentrations of CSF and serum.     

Muskuläre Sehnenfäden in der linken Herzkammer

Zusammenfassung Die Chorda muscularis persistens stellt eine Hemmungsmißbildung am Segelklappensystem dar. Sie kommt hauptsächlich am vorderen Papillarmuskel des linken Ventrikels vor. In den meisten Fällen stellt sie ein harmloses Relikt dar. Gelegentlich kann sie aber bei massiver Einstrahlung in das Klappengewebe ernste funktionelle Störungen des Klappenschlusses in Form einer Insuffizienz bewirken. Bei Vorliegen einer Mitralinsuffizienz mit unklarer Genese sollte auch an diese Anomalie gedacht werden.

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Muscular chordae tendineae of the left cardiac ventricle

Summary The Chorda muscularis persistens, an arrest of development, is a variation of the connection between the papillary muscles and the valve cusps whereby the papillary muscle is connected with the valve cusp without a chorda tendinea. It is chiefly found on the musculus papillaris anterior of the left ventricle. The usually harmless chorda muscularis persistens occasionally may cause insufficiency of the mitral valve if fibers of the papillary muscle merge with the structure of the valve cusps. In every case of a mitral insufficiency of occult cause this anomaly should be considered.

     

Characteristics of slow potentials from the frog epiphysis (rana esculenta); Possible mass photoreceptor potentials

In situ recorded responses (electropinealogram or EPG) are: (1) not color coded: (2) composed of a fast (lasting < 1sec) photopic component (λ_max > 500 nm) and a slower (lasting 1 sec to 1 min) scotopic component (λ_max ≈- 500 nm): (3) able to dark-adapt over at least 3.5 log units over a few half hours; (4) dominated by the scotopic (slow) component even at light levels where the spike activity is photopic; (5) show light integration according to Bloch's law up to ≈-5 sec in the dark-adapted state, up to ≈-500 msec in the light-adapted state; (6) also slow in light adapting requiring up to 30 min. The contention that they represent receptor potentials is based on: (a) the lack of a knee in the two-component dark-adaptation curve, (b) the dominance of a scotopic spectral sensitivity curve at photopic adaptation levels and (c) the limited number of cells and cell types in the organ.     

Residues of PCB's and DDT in the western Lake Superior ecosystem

Fish from western Lake Superior (1972–73) contained DDT and PCB residues at concentrations greater than 0.1 ppm. The most predominant PCB's were those containing 3 to 6 chlorine atoms per molecule, and GLC data indicated that the mixtures were most like the commercial product Aroclor^® 1254. Other chlorinated contaminants identified by GC/MS analyses and occurring at concentrations less than 0.1 ppm were hexachlorobenzene (C₆Cl₆), chlordane, nonaclor, and dieldrin. Lindane, which has been previously reported in Lake Superior, was below the detection limit of approximately 0.01 ppm.The relationship between the size of lake trout and the concentration of total DDT in the fish was compared to measurements reported in previous studies. The comparison suggests that DDT residues have declined since 1968. The concentration of PCBs was estimated to be 0.8 ng/L in Lake Superior water and 0.1 ppm in large zooplankton. The apparent bioconcentration factor for PCBs in Lake Superior fish ranged from 10⁵ to 10⁶. The concentration of total DDT and PCBs in the larger Lake Superior fish exceeded the 5 ppm tolerance level established by the U.S. Food and Drug Administration for these chemicals in fish to be used for human consumption.