A study on the communication between the pectoral nerve and the extramural nerve branches of the intercostal nerves]

Kumaki et al. (1979) defined the extramural nerve as the rudimentary sensory nerve which appeared on the upper thoracic wall; it branched off the root of the lateral cutaneous nerve of the second, third or fourth intercostal nerve, ran inferomedially adhering to the fascia of the intercostalis externus muscle and ended supplying the membrane covering the adjacent rib. They also stated that the extramural nerve (Rxm) occasionally became a cutaneous nerve which pierced the pectoralis muscles and supplied the skin covering the thoracic wall similar to the lateral cutaneous nerve (Rcl) or the anterior cutaneous nerve (Rca). Further, they proposed that the muscular nerves to the obliquus externus abdominis muscle which are usually situated below the fifth rib might be considered a part of this Rxm series. Although the definition of Rxm is still not widely accepted, Rxm is thought to be a key morphological factor influencing the variations of peripheral nerve arrangement on the thoracic wall. In the student course of gross anatomy dissection at Iwate Medical University School of Medicine during the years 1987-1991, three cases of Rxm communicating with the pectoral nerve and supplying the pectoralis major muscle were observed. Some cases have been reported in which Rcl innervates part of the pectoral muscles. However, the communication between the pectoral nerve and Rxm has not yet been discussed. Therefore, to clarify the morphological significance of the communication between Rxm and the pectoral nerve, the branching pattern and the distribution of the pectoral nerves were extensively investigated and the intramuscular nerve supply of some pectoral nerves, especially the pectoral nerves which communicated with Rxm, was examined in detail under a stereomicroscope. The results are summarized as follows: 1. In the first case, Rxm of the second intercostal nerve originated from Rcl, ran inferomedially adhering to the fascia of the intercostalis externus muscle and pierced the origin of the pectoralis minor muscle at the third intercostal space. Then Rxm turned superolaterally to communicate with a pectoral nerve which originated from the loop composed of the lateral and medial pectoral nerves and passed inferior to the pectoralis minor muscle. After communication, the pectoral nerve with Rxm supplied the caudalmost part of the sternocostal portion of the pectoralis major muscle. In the second case, a similar branch of Rxm of the second intercostal nerve passed inferior to the pectoralis minor muscle.(ABSTRACT TRUNCATED AT 400 WORDS)     

Characterization of acetate uptake by the colonic epithelial cells of the rat

The characteristics of acetate uptake by colonic epithelial cells of the rat were studied. Clear saturation kinetics of acetate uptake were not observed in these experiments at either 0° C or 30° C. A decrease in the pH of the medium markedly increased the acetate uptake. The activation energy for acetete uptake derived from an Arrhenius plot was about 6.1 kcal/mole. Among the inhibitors tested, no effective inhibition of acetate uptake at 0° C was observer. Metabolic inhibitors severely inhibited transport at 30° C. Inhibition of acetate uptake by other short chain fatty acids, which was non-competitive, was observed. The finding that efflux from the cells was stimulated in the presence of compounds such as pyruvate and bicarbonate supported the notion of a close interrelationship between weak electrolyte transports in vivo. Although the H⁺ gradient across the cell membrane is suggested to be one of the factors determining the uptake rate, it seems difficult to explain all the results in this way.     

Benzylpenicillin preparations can evoke a systemic anaphylactic reaction in guinea pigs

All of the five commercially available benzylpenicillin preparations obtained from different sources and a PcG preparation prepared by filtration of a commercial PcG on Sephadex G10 elicited the systemic anaphylactic reactions in guinea pigs which had been immunized with benzylpenicilloyl (BPO)-Ascaris extract conjugate (BPO-As) mixed with aluminum hydroxide gel. These preparations could evoke no such reactions in guinea pigs immunized with BPO-bovine gamma globulin conjugate (BPO-BGG) emulsified with complete Freund's adjuvant. The severity of the systemic anaphylactic reactions correlated significantly with the titers of either 8-day passive cutaneous anaphylactic (8-day PCA) reactions or 4-hr PCA reactions evoked with the same benzylpenicillin preparations. In vitro benzylpenicillin preparation contracted the tracheas of the guinea pigs immunized with BPO-As. These results indicated that the commercially available benzylpenicillin preparations have enough antigenicity to evoke systemic anaphylactic reactions in guinea pigs immunized with BPO-As mixed with aluminum hydroxide gel. Such guinea pigs represent an animal model for investigation of penicillin allergy.     

Enterostatin increases extracellular serotonin and dopamine in the lateral hypothalamic area in rats measured by in vivo microdialysis

The effect of enterostatin injection into the rat lateral hypothalamic area (LHA) on serotonin and dopamine releases in extracellular space was investigated by in vivo microdialysis technique. The primary focus being to understand whether a small amount of enterostatin crossing the blood-brain barrier correlates with activity changes in serotonergic and dopaminergic nervous systems or not. We found a significant elevation in serotonin release in the LHA. The enterostatin perfusion also induced a smaller but significant increase in dopamine level than serotonin one. This result suggests that enterostatin plays some sort of role in the control of feeding of fat through the control serotonergic and dopaminergic satiety mechanism.     

Five-year follow-up study of mother-to-child transmission of Helicobacter pylori infection detected by a random amplified polymorphic DNA fingerprinting method

Recent studies have speculated on the possible role of the mother in transmitting Helicobacter pylori infection to their children. In an attempt to either prove or disprove this supposition, we investigated the rates of infection of children born to H. pylori-positive mothers from birth to 5 years of age using serology and the stool antigen test. When infection of the children did occur, the strains from the children were compared to those of their mothers using DNA analysis. Sixty-nine of the 350 pregnant mothers (19.7%) had a positive serology for H. pylori. Fifty-one children underwent serological examinations and stool antigen tests at 4 to 6 days after birth, followed by 1, 3, and 6 months. They were continuously given the stool antigen test at 4- to 6-month intervals until the age of 5 years. Gastric juice samples were collected from the infected children and their mothers for culture and DNA analyses using a random amplified polymorphic DNA fingerprinting method. None of the 51 children acquired H. pylori infection during the first year of life. Of the 44 children enrolled in a 5-year follow-up study, five (11%) acquired H. pylori infection. They acquired the infection at the age of 1 year 2 months, 1 year 3 months, 1 year 6 months, 1 year 8 months, and 4 years 4 months. Random amplified polymorphic DNA fingerprinting confirmed that the strains of the five children exhibited DNA fingerprinting patterns identical to those of their mothers. These findings suggest that mother-to-child transmission is the most probable cause of intrafamilial spread of H. pylori.     

Usefulness of continuous air tonometry for evaluation of splanchnic perfusion during cardiopulmonary bypass

Although gastric mucosal tonometry has been reported as a useful method to assess splanchnic perfusion during cardiovascular surgery, the conventional discontinuous method of tonometry (saline tonometry) was cumbersome and prone to systematic errors. A new automated system of air tonometry (Tonocap; Datex Ohmeda, Helsinki, Finland) allows for frequent (every 10 minutes) measurement of gastric regional CO2 (PrCO2) and may be more suitable as a monitoring system in cardiac patients. We evaluated the usefulness of continuous air tonometry as a marker of splanchnic perfusion during cardiopulmonary bypass (CPB). In 19 patients (53-79 years, mean 63 years) who underwent cardiovascular surgery under standard CPB with mild hypothermia (32 degrees C) from January 2001 to May 2002, the PrCO2 and calculated intramucosal pH (pHi) of gastric tonometry was monitored using Tonocap, and their relation to postoperative visceral organ function was evaluated. The pHi significantly increased after initiation of CPB from 7.32 +/- 0.07 to 7.43 +/- 0.10 (p < 0.05) and then consistently decreased in all patients to 7.39 +/- 0.09 at the end of CPB. The value of PrCO2 significantly (p < 0.01) correlated with the value of pHi. The lowest value of pHi during CPB was significantly related to blood urea nitrogen (r = -0.75, p < 0.05), serum creatinine (r = -0.78, p < 0.05), creatinine clearance (r = 0.68, p < 0.05) on postoperative day 1, and blood urea nitrogen (r = -0.84, p < 0.01) on day 3. In contrast, arterial blood lactate level, venous oxygen saturation, and routinely measured hemodynamics (e.g., pump flow, arterial pressure) during CPB were unrelated to the postoperative visceral organ function. These results suggest that continuous monitoring of gastric regional CO2 and pHi by air tonometry system is useful for the evaluation of splanchnic perfusion during CPB and may contribute to improve CPB technique by allowing the early detection of visceral malperfusion.     

Molecular assembly of RNA polymerase II from the fission yeast Schizosaccharomyces pombe: subunit–subunit contact network involving Rpb5

Background: Eukaryotic RNA polymerase II is composed of more than 10 polypeptide chains. The minimum and essential subunits for RNA synthesis have not yet been identified. Toward this ultimate goal, we analysed the topological arrangement of the putative subunits. Here we report a subunit–subunit contact network involving subunit 5 of the fission yeast Schizosaccharomyces pombe RNA polymerase II.
Results: The rpb5 ⁺ gene encoding subunit 5 of RNA polymerase II was cloned from the fission yeast Schizosaccharomyces pombe . The polypeptide predicted from DNA sequence of the rpb5 ⁺ gene consists of  210 amino acids with a calculated molecular weight of 23 914. The homology of the amino acid sequence is 55% and 43% with Saccharomyces cerevisiae RPB5 and human hRPB25, respectively. Far-Western blot analysis of S. pombe RNA polymerase II using ³²P-labelled recombinant Rpb5 fused to glutathione S-transferase (GST) as a probe, indicated that Rpb5 binds strongly to membrane-immobilized Rpb1, Rpb2 and Rpb3 and weakly to Rpb5 and a 15-kDa subunit (Rpb8 or Rpb11). In agreement with this result, the ³²P-labelled Rpb3 probe showed a strong binding signal against Rpb5 in addition to Rpb1 and Rpb2. The existence of Rpb5–Rpb3 contact was supported by detection of complexes formed between these two proteins synthesized in vitro using protein-immobilized beads.
Conclusion: Rpb3 and Rpb5, the putative subunits of RNA polymerase II, associate each other to form binary complexes. These two subunits also bind to the two large subunits, Rpb1 and Rpb2, independently.     

Identification of a novel adhesion molecule involved in the virulence of Legionella pneumophila

Legionella pneumophila is an intracellular bacterium, and its successful parasitism in host cells involves two reciprocal phases: transmission and intracellular replication. In this study, we sought genes that are involved in virulence by screening a genomic DNA library of an L. pneumophila strain, 80-045, with convalescent-phase sera of Legionnaires' disease patients. Three antigens that reacted exclusively with the convalescent-phase sera were isolated. One of them, which shared homology with an integrin analogue of Saccharomyces cerevisiae, was named L. pneumophila adhesion molecule homologous with integrin analogue of S. cerevisiae (LaiA). The laiA gene product was involved in L. pneumophila adhesion to and invasion of the human lung alveolar epithelial cell line A549 during in vitro coculture. However, its presence did not affect multiplication of L. pneumophila within a U937 human macrophage cell line. Furthermore, after intranasal infection of A/J mice, the laiA mutant was eliminated from lungs and caused reduced mortality compared to the wild isolate. Thus, we conclude that the laiA gene encodes a virulence factor that is involved in transmission of L. pneumophila 80-045 and may play a role in Legionnaires' disease in humans.