Factors which affect the relative contributions of ovarian and uterine arteries to the blood supply of reproductive organs in guinea pigs

The establishment and stability of the behavioral baseline for rats in relation to the schedule of differential reinforcement of low rate under water reinforcer (DRL 20 sec for water) were studied, with the following results: When the DRL value was gradually stepped up from 1 sec to 20 sec with the advance of the sessions from 1to 16, the establishment of the behavioral baseline was slower than when DRL 20 sec was applied from the start. The establishment of the baseline was clearly accelerated by the prolongation of the length of time for training in one session from 60 min to 120 min. The baseline remained highly stable without being affected by the intermittent administration (2-3 times a week) of methamphetamine and diazepam, each in doses from 0.06 to 1.0 mg/kg, and of caffeine and pentobarbital, each in doses from 1.2 to 20 mg/kg, or by the discontinuation of the test from 1 to 15 days. However, during the retraining period following the test discontinuation it was found that the baseline fluctuated for a long time due to the elimination of water deprivation. The baseline stability, once established, could be maintained through about 300 daily sessions, with only a slight dependence on the change in environmental conditions such as humidity, temperature, and the season.     

A G protein gamma subunit-like domain shared between RGS11 and other RGS proteins specifies binding to Gbeta5 subunits

Regulators of G protein signaling (RGS) proteins act as GTPase-activating proteins (GAPs) toward the alpha subunits of heterotrimeric, signal-transducing G proteins. RGS11 contains a G protein gamma subunit-like (GGL) domain between its Dishevelled/Egl-10/Pleckstrin and RGS domains. GGL domains are also found in RGS6, RGS7, RGS9, and the Caenorhabditis elegans protein EGL-10. Coexpression of RGS11 with different Gbeta subunits reveals specific interaction between RGS11 and Gbeta5. The expression of mRNA for RGS11 and Gbeta5 in human tissues overlaps. The Gbeta5/RGS11 heterodimer acts as a GAP on Galphao, apparently selectively. RGS proteins that contain GGL domains appear to act as GAPs for Galpha proteins and form complexes with specific Gbeta subunits, adding to the combinatorial complexity of G protein-mediated signaling pathways.     

Potato gun ocular injury

PURPOSE: This study aimed to identify a dangerous new weapon capable of causing damage to the ocular and periocular regions. METHODS: The authors report two patients who had penetrating ocular injury in the past year because of homemade recreational potato guns. RESULTS: In one 14-year-old boy, projectiles from the firing of a potato gun resulted in orbital and cranial injuries that were life threatening with widespread fractures, marked disruption of facial structures, a cerebrospinal fluid fistula requiring bifrontal surgical repair, and loss of one eye. In a separate accident with a different potato gun, a 14-year-old boy who was wearing glasses at the time of injury had a sight-threatening perforating corneal laceration. CONCLUSION: Practitioners must be aware of the existence of these new, homemade unregulated devices. Information about the use and construction of these guns is widespread on the Internet, but no injuries resulting from these guns currently are documented in the medical literature.     

Muscle proton T2 relaxation times and work during repetitive maximal voluntary exercise

We studied the effects of progressive maximal voluntary handgrip contractions (MVCs) on muscle proton spin-spin (T2) relaxation times and work, measured as the integrated force vs. time curve (FTI). Six healthy volunteers performed 10, 20, 40, and 80 MVCs in a 0.35-T magnet on four separate occasions. Repeated measures analyses of variance of increases in T2 and FTI during successive bouts were significant (P < 0.005 and P < 0.001, respectively). FTI increased with successive bouts to a greater extent than did muscle T2 (P < 0.05). For T2, the Helmert contrast judged the 10-MVC response lower than the mean of the remaining responses (P < 0.005), and the differences between all others compared with the means of subsequent responses were not significant, indicating a "flattening" of the T2 response after the increase from 10 to 20 repetitions. For FTI, all the single degree of freedom Helmert contrasts were significant (P < 0.001), indicating a continual increase in response over increased MVCs. The curved nature of the T2 response conformed best to a hyperbolic function, suggesting that a limit of approximately 32% exists for the change in T2 during progressively longer bouts of MVCs. A limit in the T2 response is consistent with the existence of a limit in the amount of water that muscle can take up from the vasculature during exertion.     

Blood and plasma selenium levels and GSH-Px activities in patients with arterial hypertension and chronic heart disease

Among the 57 monoclonal antibodies analyzed within the T-cell group of the Second International Swine CD Workshop, one mAb fell within cluster T14a that included the CD6 standard a38b2 (No. 175). The new mAb MIL8 (No. 082) and a38b2 both precipitated from activated T-cells a 150 kDa monomeric protein. Staining patterns on the various cell types were similar. There was no inhibition of binding of either mAb to peripheral blood T-cells with the opposite mAb. The new mAb, MIL8, reacts with a separate epitope on porcine wCD6.     

Recognition of sequence-directed DNA structure by the Klenow fragment of DNA polymerase I

Time-resolved fluorescence spectroscopy was used to investigate the influence of sequence-directed DNA structure upon the interaction between the Klenow fragment of DNA polymerase I and a series of defined oligonucleotide primer/templates. 17/27-mer (primer/template) oligonucleotides containing a dansyl fluorophore conjugated to a modified deoxyuridine residue within the primer strand were used as substrates for binding to Klenow fragment. The time-resolved fluorescence anisotropy decay of the dansyl probe was analyzed in terms of two local environments, either solvent-exposed or buried, corresponding to primer/templates positioned with the primer 3' terminus in the polymerase site or the 3'-5' exonuclease site of the enzyme, respectively. Equilibrium constants for partitioning of DNA between the two sites were evaluated from the anisotropy decay data for primer/templates having different (A + T)-rich sequences flanking the primer 3' terminus. Primer/templates with AAAATG/TTTTAC and CGATAT/GCTATA terminal sequences (the nucleotides on the left refer to the last six bases at the 3' end of the primer, and the nucleotides on the right are the corresponding bases in the template) were bound mostly at the polymerase site. The introduction of single mismatches opposite the primer 3' terminus of these DNA substrates increased their partitioning into the 3'-5' exonuclease site, in accord with the results of an earlier study [Carver, T.E., Hochstrasser, R.A., and Millar, D.P. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 10670-10674]. In contrast, a primer/template with the terminal sequence CAATTT/GTTAAA, containing an A-tract element AATTT, exhibited a surprising preference for binding at the 3'-5' exonuclease site, despite the absence of mismatched bases in the DNA substrate. Interruption of the A-tract with a single AG step, to give the terminal sequence CAGTTT/GTCAAA, reversed the effect of the A-tract, causing the DNA to partition in favor of the polymerase site. Moreover, the presence of a single mismatch opposite the primer 3' terminus was also sufficient to reverse the effect of the A-tract, resulting in a distribution of DNA between polymerase and 3'-5' exonuclease sites that was similar to that observed for the other mismatched DNA substrates. Taken together, these results suggest that the A-tract adopts an unusual conformation that is disruptive to binding at the polymerase site. The effect of the A-tract on binding of DNA to the polymerase site is discussed in terms of the unusual helix structural parameters associated with these sequence elements and the difference between the local geometry of the A-tract and the conformation adopted by duplex DNA within the polymerase cleft. The results of this study show that in addition to base mismatches, Klenow fragment can also recognize irregularities in the helix geometry of perfectly base-paired DNA.