Spaceflight affects postnatal development of the aortic wall in rats.

We investigated effect of microgravity environment during spaceflight on postnatal development of the rheological properties of the aorta in rats. The neonate rats were randomly divided at 7 days of age into the spaceflight, asynchronous ground control, and vivarium control groups (8 pups for one dam). The spaceflight group rats at 9 days of age were exposed to microgravity environment for 16 days. A longitudinal wall strip of the proximal descending thoracic aorta was subjected to stress-strain and stress-relaxation tests. Wall tensile force was significantly smaller in the spaceflight group than in the two control groups, whereas there were no significant differences in wall stress or incremental elastic modulus at each strain among the three groups. Wall thickness and number of smooth muscle fibers were significantly smaller in the spaceflight group than in the two control groups, but there were no significant differences in amounts of either the elastin or collagen fibers among the three groups. The decreased thickness was mainly caused by the decreased number of smooth muscle cells. Plastic deformation was observed only in the spaceflight group in the stress-strain test. A microgravity environment during spaceflight could affect postnatal development of the morphological and rheological properties of the aorta.

[Bacteria isolated from surgical infections and their susceptibilities to antimicrobial agents --special references to bacteria isolated between April 2008 and March 2009].

Bacteria isolated from infections in abdominal surgery during the period from April 2008 to March 2009 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 712 strains including 18 strains of Candida spp. were isolated from 173 (80.5%) of 215 patients with surgical infections. Three hundred and sixty-six strains were isolated from primary infections, and 346 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-negative bacteria were predominant, followed by aerobic Gram-negative bacteria, while from postoperative infections aerobic Gram-positive bacteria were predominant, followed by anaerobic Gram-negative bacteria. Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus spp. was highest, followed by Streptococcus spp., and Staphylococcus spp. in this order, from primary infections, while Enterococcus spp. was highest, followed by Staphylococcus spp. from postoperative infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae and Pseudomonas aeruginosa, in this order, and from postoperative infections, P aeruginosa was most predominantly isolated, followed by E. coli, Enterobacter cloacae, and K. pneumoniae. Among anaerobic Gram-positive bacteria, the isolation rate of Eggerthella lenta was the highest from primary infections, followed by Parvimonas micra, Streptococcus constellatus and Gemella morbillorum, and from postoperative infections, E. lenta was most predominantly isolated. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis was the highest from primary infections, followed by Bacteroides thetaiotaomicron, Bacteroides ovatus and Bilophila wadsworthia, and from postoperative infections, B. fragilis was most predominantly isolated, followed by B. thetaiotaomicron, B. wadsworthia and B. ovatus, in this order. In this series, we noticed no vancomycin-resistant methicillin-resistant S. aureus, and Enterococcus spp., nor multidrug-resistant P aeruginosa. We should carefully follow up B. wadsworthia which was resistant to various antibiotics, and also Bacteroides spp. which was resistant to many beta-lactam antibiotics.

[Bacteria isolated from surgical infections and their susceptibility to antimicrobial agents--special reference to bacteria isolated between April 2007 and March 2008].

Bacteria isolated from infections in abdominal surgery during the period from April 2007 to March 2008 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 707 strains including 24 strains of Candida spp. were isolated from 181 (79.0%) of 229 patients with surgical infections. Three hundred and ninety-five strains were isolated from primary infections, and 288 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-negative bacteria were predominant, followed by aerobic Gram-negative bacteria, while from postoperative infections aerobic Gram-positive bacteria were predominant, followed by anaerobic Gram-negative bacteria. Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus spp. was highest, followed by Streptococcus spp., and Staphylococcus spp. in this order, from primary infections, while Enterococcus spp. was highest, followed by Staphylococcus spp. from postoperative infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae, Pseudomonas aeruginosa and Enterobacter cloacae, in this order, and from postoperative infections, P. aeruginosa was most predominantly isolated, followed by E. cloacae, E. coli and K. pneumoniae. Among anaerobic Gram-positive bacteria, the isolation rate of Parvimonas micra was the highest from primary infections, followed by Streptococcus constellatus and Gemella morbillorum, and from postoperative infections, Anaerococcus prevotii was most predominantly isolated. Among anaerobic Gram-negative bacteria, the isolation rate of both Bacteroides fragilis and Bilophila wadsworthia were the highest from primary infections, followed by Bacteroides thetaiotaomicron and Campylobacter gracilis, and from postoperative infections, B. thetaiotaomicron was most predominately isolated, followed by B. fragilis, Bacteroides caccae and B. wadsworthia in this order. In this series, we noticed no vancomycin-resistant Gram-positive cocci, nor multidrug-resistant P aeruginosa. There were nine strains of coagulase-negative Staphylococci which show higher MIC against teicoplanin more than 4 gg/mL, but all of them had good susceptibilities against various anti-MRSA antibiotics. We should carefully follow up B. wadsworthia which was resistant to various antibiotics, and also Bacteroides spp. which was resistant to many beta-lactam antibiotics.

[Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents--special references to bacteria isolated between April 2003 and March 2004].

Tendency of isolated bacteria from infections in general surgery during the period from April 2004 to March 2005 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 645 strains including 17 strains of Candida spp. were isolated from 226 (79.0%) of 286 patients with surgical infections. Three hundred and seventeen strains were isolated from primary infections, and 345 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-positive bacteria and anaerobic Gram-negative bacteria were predominant, while aerobic Gram-positive bacteria were predominant from postoperative infections. The isolation rate of aerobic Gram-positive bacteria, such as Enterococcus spp. and Staphylococcus aureus were higher from both types of infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Pseudomonas aeruginosa, Klebsiella pneumoniae and Citrobacter freundii in this order, and from postoperative infections, P. aeruginosa was the most predominantly isolated, followed by E. coli, E. cloacae, and K. pneumoniae. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both primary infections followed by Bilophila wadsworthia. While the isolation rate of B. fragilis group was also the highest from postoperative infections, the following bacteria were Bacteroides thetaiotaomicron and B. wadsworthia in this order. In this series, we noticed no vancomycin-resistant Gram-positive cocci, but a few strains of moderately arbekacin-resistant MRSA. Carbapenem-resistant P. aeruginosa but not multidrug-resistant was seen in 13.3 per cents. Also cefazolin-resistant E. coli probably producing extended spectrum beta-lactamase was seen in 7.0 per cents. We should be carefully followed up the facts that an increasing isolation rates of B. fragilis group and B. wadsworthia which were resistant to both penicillins and cephems.

[Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents--special references to bacteria isolated between April 2003 and March 2004].

Tendency of isolated bacteria from infections in general surgery during the period from April 2003 to March 2004 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 455 strains including 14 strains of Candida spp. were isolated from 191(75.2%) of 254 patients with surgical infections. Two hundred and thirty-nine strains were isolated from primary infections, and 216 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-positive bacteria and aerobic Gram-negative bacteria were predominant, while aerobic Gram-positive bacteria were predominant from postoperative infections. The isolation rate of aerobic Gram-positive bacteria, such as Enterococcus spp. and Staphylococcus aureus were higher from both types of infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae, Enterobacter cloacae and Pseudomonas aeruginosa in this order, and from postoperative infections, E. coli was the most predominantly isolated, followed by P. aeruginosa, E. cloacae, and K. pneumoniae. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both types of infections. The isolation rate of anaerobic Gram-positive bacteria from primary infections and that of aerobic Gram-positive bacteria from postoperative infections were high in the last several years. In this series, we noticed no vancomycin-resistant Gram-positive cocci, but a few strains of moderately arbekacin-resistant MRSA. Carbapenm-resistant P. aeruginosa was seen in less than 10 per cents. Last year we noticed that there were cefazolin-resistant E. coli producing extended spectrum beta-lactamase, but there was no highly cefazolin-resistant E. coli in this year. In the next series, increase of both anaerobic bacteria and Enterococcus spp. should be carefully followed up.

Novel insights into coronary lumen preservation during progression of coronary atherosclerosis in coronary atherosclerosis-prone rabbits.

BACKGROUND: In coronary atherosclerosis-prone Watanabe heritable hyperlipidaemic (WHHLCA) rabbits, an animal model for low-density lipoprotein receptor deficiency and spontaneous coronary atherosclerosis, the coronary arteries show compensatory remodelling during the progression of atherosclerosis. Therefore, we analysed coronary remodelling of WHHLCA rabbits quantitatively using a method that eliminates the limitations of previous analytical methods. METHODS: Arterial remodelling was evaluated in perfusion-fixed coronary arteries of 11 WHHLCA rabbits using both new and previous analyses. With the improved methods removing limitations on quantitative analysis of arterial remodelling, we evaluated how lumen area or arterial size changed with accumulating atherosclerotic plaques compared to before plaque development. The original lumen area before plaque development was calculated using the diameter-length relationship. Wall shear stress change ratio was calculated from changes in arterial size. RESULTS: Using the old analytical method (and as seen in similar human studies), lumen area increased up to a level of 29% of cross-sectional narrowing. However, with the improved analysis, in cross-sectioning narrowing at levels below 10%, the lumen area modestly decreased, and when the cross-sectional narrowing ranged from 10-68%, the lumen area remained constant, and diminished sharply despite continued remodelling when cross-sectional narrowing reached 70% or above. Arterial remodelling progressed quantitatively to a slight increase in arterial wall shear stress as well as lumen area up to a level of 70% cross-sectional narrowing. CONCLUSIONS: These findings demonstrate marked influences of arterial tapering and individual variation of arterial size on quantitative analysis of arterial remodelling, and provide the novel insight that coronary compensatory remodelling in atherosclerosis maintains the lumen size up to levels of 70% cross-sectional narrowing in proportion to wall shear stress.

Change in the static rheological properties of the aorta in Kurosawa and Kusanagi-hypercholesterolemic (KHC) rabbits with progress of atherosclerosis.

The rheological properties of the arterial wall have intimate connections with the fine structure of the wall. Alteration in fine structure due to cardiovascular disease, such as atherosclerosis, could affect the rheological characteristics of the wall. The present study was designed to investigate changes in the static rheological properties of the aorta in Kurosawa and Kusanagi-Hypercholesterolemic (KHC) rabbits aged 10-12, 22-24 and 34-36 months in relation to histological alteration of the wall due to progression of atherosclerosis with age. Circumferential wall strips were excised from the ascending, proximal descending thoracic and proximal abdominal aortas and their stress/strain relationship was recorded. Tensile force of the wall showed a slight but insignificant decrease in the KHC rabbit group aged 10-12 months compared to that in the age-matched control group in the proximal thoracic aorta and increased significantly with ageing in the KHC rabbits in these aortic regions mainly at medium and high strain ranges. Wall stress was significantly smaller in the 10-12 months old KHC rabbit group than in the age-matched control group in the proximal thoracic and proximal abdominal aortas and increased significantly with ageing in the KHC rabbit groups chiefly at medium and high strain ranges. Incremental elastic modulus determined at 50% stretching of the initial length of the wall strip was also significantly lower in the KHC rabbit group aged 10-12 months in comparison to that in the age-matched control group and increased significantly with ageing in the KHC rabbit group. The intima thickened severely with abundant foam cells in the KHC rabbits aged 10-12 months. With increasing age, collagen and elastin fibres showed signs of gradual proliferation among the foam cells. The aortic wall in KHC rabbits was viscoelastic in the relatively early stage of atherosclerosis due to abundant foam cells, and thereafter increased in stiffness gradually with fibrous proliferation and calcification. We can conclude that the static rheological properties of the atherosclerotic aortic wall changed in association with alteration in the microstructure of the wall with progression of atherosclerosis.

[Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents--special references to bacteria isolated between April 2002 and March 2003].

Tendency of isolated bacteria from infections in general surgery during the period from April 2002 to March 2003 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 334 strains were isolated from 131 (75.3%) of 174 patients with surgical infections. One hundred and seventy-one strains were isolated from primary infections, and 163 strains were isolated from post-operative infections. From primary infections, anaerobic Gram-positive bacteria were predominant, while aerobic Gram-positive bacteria were predominant from postoperative infections. Among aerobic Gram-positive bacteria, although the isolation rate of Staphylococcus aureus was the highest, followed by that of Enterococcus faecalis from primary infections, the isolation rate of E. faecalis was the highest from postoperative infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae and Pseudomonas aeruginosa in this order, and from postoperative infections, E. coli was the most predominantly isolated, followed by P. aeruginosa, Enterobacter cloacae, and Citobacter freundii. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both types of infections. The isolation rate of aerobic Gram-negative bacteria from primary infections and that of aerobic Gram-positive bacteria from postoperative infections were high in the last several years. We noticed no vancomycin-resistant Gram-positive cocci nor P. aeruginosa producing metallo-beta-lactamase. But we noticed cefazolin-resistant E. coli probably producing extended spectrum beta-lactamase.

Characteristic change in local pulse wave velocity in different segments of the atherosclerotic aorta in KHC rabbits.

BACKGROUND: Pulse wave velocity, conventionally determined between the carotid and femoral arteries, is a useful measure to estimate stiffness of the aorta. We investigated local pulse wave velocity (LPWV) in different segments in the aorta with relatively early-stage atherosclerosis in relation to the extent and severity of atherosclerotic lesions. METHODS: Pressure waves were recorded in eight aortic positions using two catheters with one or two micromanometers to determine LPWV in the ascending aorta, distal end of the aortic arch, proximal, middle, and distal thoracic aortas, and proximal, middle, and distal abdominal aortas in Kurosawa and Kusanagi-hypercholesterolemic (KHC) and normal rabbits aged 10 to 12 months. RESULTS: The LPWV in the KHC rabbit was greatest in the aortic arch, decreased almost to the normal level in the middle and distal thoracic aorta, increased in the proximal abdominal aorta, and showed almost identical change to that in the normal rabbit in the middle and distal abdominal aortic regions. There was significant difference in LPWV in the aortic arch, proximal thoracic, and proximal abdominal aortas between the two rabbit groups. The sclerotic lesion was prominent in the aortic arch, proximal thoracic aorta, and proximal abdominal aortas. The wall was severely thickened with abundant foam cells. The significant increase in LPWV would be mainly related to the increased wall thickness in these aortic regions. CONCLUSIONS: We can conclude that LPWV reflects well the distribution and severity of atherosclerotic lesion and the increased wall thickness in the local aortic region in which pulse waves were traveled.

[Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents--special references to bacteria isolated between April 2001 and March 2002].

Isolated bacteria from infections in general surgery during the period from April 2001 to March 2002 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, four hundred and twenty strains were isolated from 175 (79.2%) of 221 patients with surgical infections. One hundred and eighty-six strains were isolated from primary infections, and 234 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-positive bacteria were predominant, while from postoperative infections, aerobic Gram-positive bacteria were predominant. Among aerobic Gram-positive bacteria, although the isolation rate of Staphylococcus aureus was the highest, followed by that of Enterococcus faecalis from primary infections, the isolation rate of E. faecalis was the highest from postoperative infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae and Pseudomonas aeruginosa in this order, and from postoperative infections, P. aeruginosa was the most predominantly isolated, followed by Enterobacter spp., E. coli and Klebsiella spp. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both types of infections. The isolation rate of aerobic Gram-negative bacteria from primary infections and that of aerobic Gram-positive bacteria from postoperative infections were high in the last several years. We noticed no vancomycin-resistant Gram-positive cocci.

Keyhole procedure: a new technique for intestinal anastomosis with a large opening and less tissue trauma, using both circular and linear staplers.

BACKGROUND: We designed a new technique, termed the keyhole procedure, that uses a linear stapler to enlarge the anastomotic opening made with a circular stapler. The present study was performed to evaluate this technique in terms of maximum bursting pressure and area of anastomotic opening and compare it with conventional anastomosis using a circular stapler in an animal model. METHODS: Anastomoses were created by the new technique or by the conventional method in swine small intestine. Anastomosis integrity was assessed by the air leakage test. Anastomotic openings were photographed and measured with an image analyzer. RESULTS: It was found that the area of the anastomotic opening obtained with the new technique was more than 3 times that of the control (P <.001). There was no significant difference between the methods in maximum bursting pressure. CONCLUSIONS: The keyhole procedure provides a larger anastomotic opening than conventional anastomosis with a circular stapler, without impairing the integrity of anastomosis.

Solitary intraperitoneal recurrence of alpha-fetoprotein-producing gastric carcinoma: report of a case.

A solitary recurrence of gastric carcinoma in the peritoneal cavity is extremely rare. We herein present a case of solitary intraperitoneal recurrence in a patient with alpha-fetoprotein (AFP)-producing gastric carcinoma. As far as we can determine, this is the first report of such a form of recurrence in a patient with gastric carcinoma who underwent a successful resection. A review of our eight patients who had AFP-producing gastric carcinoma showed a frequent association with hepatic metastasis and a poor prognosis as has been reported previously. Our patient received intra-arterial chemotherapy with low-dose cisplatin and 5-fluorouracil to prevent hepatic recurrence, but eventually developed multiple hepatic metastases after ceasing this therapy. Therefore, adjuvant intra-arterial chemotherapy may have altered the site of first recurrence in this patient.

Postnatal changes in the rheological properties of the aorta in Sprague-Dawley rats.

Postnatal changes in the rheological properties of the aortic wall were investigated in relation to morphological development of the wall in Sprague-Dawley (SD) rats at 3, 8 and 20 weeks old. The mechanical tensile characteristics of the longitudinal wall strip excised from the proximal thoracic aorta were assessed with stress-strain and stress-relaxation tests. Wall tension in the low and medium strain ranges was significantly lower in 3-week-old rats than in 8-week-old rats and in 8-week-old rats than in 20-week-old rats. Wall stress was significantly lower in 3-week-old rats than in 8- and 20-week-old rats mainly in the medium strain range, but was significantly greater in 3-week-old rats than in 8- and 20-week-old rats in the high strain range. The value of incremental elastic modulus at 3 weeks old was significantly smaller than that at 8 and 20 weeks old at a strain of 0.25 and significantly larger than that at 8 and 20 weeks old at a strain of 0.50. The value of relaxation strength at 5 min after the stretching was significantly greater at 3 weeks old than that at 8 and 20 weeks old. The wall was viscoelastic in the low and medium strain ranges at 3 weeks though large wall stress was generated in the high strain range. Histological investigation revealed that the smooth muscle layer, fine elastin fiber connecting thick elastin fibers and wall thickness were thin at 3 weeks old in comparison with those at 8 and 20 weeks old, though there was no significant difference in number of nuclei of the smooth muscle cells among the three age groups. Changes in the tensile characteristics of the wall reflected well those of the microstructure of the wall with growth. The rheological properties and microstructure of the aortic wall were close to maturation at 8 weeks in SD rats.

[Bacteria isolated from surgical infections and their susceptibilities to antimicrobial agents. Special references to bacteria isolated between April 1999 and March 2000].

The annual multicenter studies on isolated bacteria from infections in general surgery and their antimicrobial susceptibility have been conducted in Japan since July 1982. In this paper, the results obtained in the academic year 1999 (from April 1999 to March 2000) have been summarized. Two hundred seven cases were investigated, and 411 strains were isolated from 169 cases (81.6%). Of those strains, 184 and 227 strains were from primary infections and postoperative infections, respectively. In primary infections, the isolation rates of anaerobes, Streptococcus spp., and Escherichia coli were higher than in postoperative infections, while in postoperative infections, those of Gram-positive aerobes were higher than in primary infections. Staphylococcus aureus were most frequently isolated among Gram-positive aerobes, Peptostreptococcus prevotii among Gram-positive anaerobes, E. coli among Gram-negative aerobes, and Bacteroides fragilis among Gram-negative anaerobes. In primary infections, the percentage of Gram-negative aerobes, which gradually increased by the year 1998, decreased in the year 1999. The percentage of Gram-negative anaerobes increased, while that of Gram-negative bacteria was equivalent to that in the last year. In postoperative infections, the percentage of Gram-negative anaerobes, which continuously increased after the year 1990, decreased, while that of Gram-positive aerobes, which decreased in the last year, increased. Methicillin-resistant S. aureus accounted for 70.7% of S. aureus (41 strains). Either the number of strain or the percentage of MRSA decreased. The susceptibilities of E. coli and Klebsiella pneumoniae decreased against third and forth generation cephems, oxacephems, and monobactams. The susceptibilities of P. aeruginosa to carbapenems tend to decrease after the year 1997. S. aureus showed good susceptibilities to the tested drugs including arbekacin, vancomycin, and teicoplanin.

[Bacteria isolated from surgical infections and their susceptibilities to antimicrobial agents--special references to bacteria isolated between April 2000 and March 2001].

Tendency of isolated bacteria from infections in general surgery and their antimicrobial susceptibilities during the period from April 2000 to March 2001 were investigated in a multicenter study in Japan, and the following results were obtained. The number of cases investigated as objectives was 234 for one year. A total of 388 strains (136 strains from primary infections and 252 strains from postoperative infections) were isolated from 165 cases (70.5% of total cases). In primary infections, anaerobic Gram-positive bacteria were predominant, while from postoperative infections, aerobic Gram-positive bacteria were predominant. Among aerobic Gram-positive bacteria, the isolation rate of Enterococcus faecalis was the highest, followed by that of Staphylococcus aureus from postoperative infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae and Pseudomonas aeruginosa in this order, and from postoperative infections, P. aeruginosa was the most predominantly isolated, followed by Enterobacter spp. and Klebsiella spp. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both types of infections. There was no vancomycin-resistant S. aureus nor Enterococcus spp. Among anaerobic bacteria, there were many resistant strains against penicillins and cephems with MICs higher than 100 micrograms/ml, and the same trend was observed among other Bacteroides spp. and Prevotella spp.