Angiostrongylus cantonensis: Rejection of pulmonary arterial transfers of lung stage worms

Experimental transfer of the lung stage worms of Angiostrongylus cantonensis was performed between permissive hosts (rats) and between permissive (rat) and nonpermissive hosts (guinea pigs and rabbits). These worms from rats were rejected when implanted into nonpermissive hosts. Unexpectedly, similar worms did not survive well even in permissive hosts; the majority of recipient rats did not have first-stage larvae (L₁) in their stools and, even when positive for L₁, the number of the larvae shed was few. These findings contrast with the successful pulmonary arterial transfer of younger, intracranial-stage worms. It was shown that differences in rat strain between donor and recipient had no significant effect on the subsequent worm survival in recipient hosts. The alteration of maintaining conditions of the intrapulmonary worms, prior to transfer, in terms of temperature, media, and maintaining period, also showed no profound effect on the subsequent worm survival. The kinetics of precipitating and reaginic antibody levels in rats implanted with the intrapulmonary worms were analogous to those in rats with intracranial-stage worms. The findings indicate that some qualitative differences may exist between the worms obtained from two different sites.     

One step purification procedure of elastase from pancreatic powder by affinity chromatography

Pancreatic elastase was isolated from acetone powder of porcine pancreas by a one step purification procedure on a trialanyl CH-Sepharose 4B affinity column. This column exhibited affinity not only for active elastase but also for trypsin and chymotrypsin which were present in the same pancreatic powder. However, as the extent of affinity toward elastase is considerably higher, the proper conditions were determined with which the adsorbed elastase was isolated in a highly purified form. The yield of elastolytic activity ranged from 60–85% and the purified elastase was shown to be one component by polyacrylamide disc electrophoresis.     

Aphidicolin: a specific inhibitor of DNA polymerases in the cytosol of rat liver.

Aphidicolin, a tetracyclic diterpenoid, is known to be antiviral and to inhibit the incorporation of thymidine into DNA of cultured human embryonic lung cells. We examined effects of the compound on the activity of several DNA polymerases obtained from subcellular fractions of rat liver. Aphidicolin at a concentration of 15 μg/ml caused a 85% reduction in level of the activity of crude and partially purified DNA polymerases from the cytosol. However, aphidicolin even at a concentration of 75 μg/ml failed to affect the activity of crude and partially purified DNA polymerases from nuclear and mitochondrial fractions.     

In vitro construction of bacteriophage λ and plasmid DNA molecules containing DNA fragments from bacteriophage T4

Restriction endonucleases EcoRI and HindIII generated fragments of T4 cytosine-containing DNA were inserted into bacteriophage vector λgtSu_III and plasmid vectors pMB9 and pBR313. Resulting clones were screened for hybridization with ³²P labeled T4 tRNA. Recombinant bacteriophages and plasmids were isolated which contained a T4 fragment coding for T4 RNA species 1 and 2 and T4 tRNA^Arg. Selected λ-T4 hybrid bacteriophages were grown to high titer and their DNA analyzed by gel electrophoresis.     

Transplacental transmission of BK virus in human.

The prevalance and distribution of BK virus antibody in women during pregnancy and the occurrence of transplacental transmission of BK virus was determined by measurement of IgM antibody in the serum. Sera were collected from 63 nonpregnant women, 71 women who had experienced spontaneous abortion, 80 in the first trimester of pregnancy and the same 80 at delivery. Umbilical cord blood was also taken at delivery. Hemagglutination inhibition (HI) tests for BK virus used the micromethod of Gardner. Results indicate that a significant level of HI antibody was present in 70% of sera from all 4 experimental groups. This showed that BK virus infection was not limited to cases of spontaneous abortion. Of the 80 pregnant mothers, 6 showed a 4-fold or greater HI antibody seroconversion to BK virus after delivery. Of these 6 seroconversion patients, sensitive antibody was detected in 3 umbilical cords. Umbilical cords of those without seroconversion had no sensitive antibody. As evidenced by 2-NE-sensitive antibody, BK virus infections were also recognized in 6 of 71 women who aborted, 4 of 80 in the first trimester of pregnancy and 2 collected after delivery. The 2-ME-sensitive antibody was not found in any of 63 samples from nonpregnant women. Data indicate that 2-ME-sensitive antibody was present only in sera of women during pregnancy and after abortion. It may be possible that BK virus persists in a latent form in many healthy women and becomes activated during pregnancy.     

Influence of surface anesthesia on the pressure pain threshold measured with different-sized probes

Transcutaneous pressure with pressure probes of arbitrary diameters have been commonly used for measuring the threshold and magnitude of muscle pain, yet this procedure lacks scientific validation. To examine the valid probe dimensions, we conducted physiological experiments using 34 human subjects. Pin-prick pain, pressure pain threshold (PPT) to pressure probes of various diameters, heat pain threshold, and electrical pain threshold of deep tissues were measured before and after application of surface lidocaine anesthesia to the skin surface over the brachioradial muscle in a double-blinded manner. The anesthesia neither affected PPT with larger probes (diameters: 1.6 and 15?mm) nor increased electric pain threshold of deep structures, whereas it diminished pain count in pin-prick test and PPT with a 1.0?mm diameter probe, suggesting that mechanical pain thresholds measured with 1.6 and 15?mm probes reflect the pain threshold of deep tissues, possibly muscle. Pain thresholds to heat did not change after application of the anesthesia. These results suggest that larger pressure probes can give a better estimation of muscular pain threshold.