Biomedical subjects

A Nakamitsu

Publications and source records attributed to A Nakamitsu.

8 recordsLinked to original sources

PubMed2001

Kupffer cell function in ischemic and nonischemic livers after hepatic partial ischemia/reperfusion.

Hepatic partial ischemic/reperfusion (I/R) injury, in which ischemic and nonischemic areas of the liver are likely to respond to each other after reperfusion, often occurs following hepatobiliary surgical procedures. Kupffer cells (KCs) are considered to play a major role in hepatic I/R injury. To study the activation of KCs in ischemic and nonischemic liver tissues following hepatic I/R, we investigated the superoxide generation and proinflammatory cytokine production of KCs in both liver parts in a rat model of partial hepatic I/R injury. KC superoxide generation in the ischemic and nonischemic lobes was upregulated 6 and 24 h after reperfusion, respectively, and then accelerated. The production of interleukin-1beta (IL-1beta) by KCs in the ischemic lobes increased during the early and late phases, 6 h and 48-72 h after reperfusion, respectively. A late increase in IL-1beta production was also observed in the nonischemic lobes. Production of tumor necrosis factor-alpha (TNF-alpha) increased 6-24h after reperfusion in both lobes. Upregulation of IL-1beta mRNA in the ischemic lobes preceded the upregulation of TNF-alpha mRNA in both lobes. The hepatic partial I/R process results in activation of KCs in ischemic and nonischemic areas of the liver. The KCs are activated during the early phase after reperfusion in the ischemic areas, followed by activation in both the ischemic and nonischemic areas. This could be a cause of liver dysfunction after partial hepatic I/R during surgery.

Animals↗

PubMed1995

Severity and predicted outcome of postoperative Pseudomonas aeruginosa infections.

The severity and predicted outcome of postoperative Pseudomonas aeruginosa (P. aeruginosa) infections (PPAI) was evaluated using a severity scoring system based on a simplification and modification of the APACHE II system. A total of 86 patients in whom P. aeruginosa was isolated from various sources were examined. PPAI developed in 50 patients, resulting in an overall mortality rate of 24%. An increased severity score (SS) correlated with an increased risk of developing PPAI. Thus, PPAI developed in 33% of the patients with an SS of 0-1, in 66.7% of those with an SS of 2-3, and in 100% of those with an SS of 6 or higher. Moreover, the mortality rate of the patients with an initial score of 6 or higher was 50%. The mean (+/- SD) initial severity score was 5.4 +/- 2.9 for survivors and 2.9 +/- 2.6 for nonsurvivors (P < 0.01). In the patients who subsequently died, the SS remained high throughout the clinical course despite therapy, whereas in the survivors the SS decreased progressively, reflecting a favorable clinical course. These results suggest that our severity scoring system was useful for predicting outcome and monitoring the response of PPAI to therapy.

Adult↗

PubMed1994

[A study of nosocomial infections by the comparison of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa].

The objective of this study was to investigate nosocomial infections by the comparison of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. We made a serological classification of 262 strains of Pseudomonas aeruginosa between 1983 and 1991. Group E strains were prevalent in 1987 and group F strains after 1990. Both these groups strains were resistant to several antibiotics, and were scarcely detected from the appendix contents in appendicitis that originated outside the hospital. Therefore we presumed these were nosocomial pathogens. With the countermeasures to nosocomial infections from 1987 on the isolation rate of enterotoxin type B and C MRSA strains decreased. Following this MRSA change, almost group E strains disappeared in Pseudomonas aeruginosa. Whereas type AC MRSA began to isolated abruptly from 1990, and the isolation of group F strains increased simultaneously. Type B and C strains still remained high sensitivity to minocycline. Type AC which have already gotten resistance to minocycline took the place of type B and C and prevalented. Similarly group F in Pseudomonas aeruginosa took the place of group E as soon as the former acquired resistance to carbapenem.

Cross Infection↗

PubMed1993

A study on postoperative enteritis caused by methicillin-resistant Staphylococcus aureus.

We investigated the production of staphylococcal enterotoxin (SE) with respect to coagulase types by methicillin-resistant Staphylococcus aureus (MRSA). A total of 138 strains of MRSA, which were isolated from clinical materials in the surgical ward between 1983 and 1990, were studied. Coagulase type IV strains produced SE A only, whereas coagulase type II strains were classified into four groups by SE production: SE B producing strains (32.7%), SE C producing strains (29.8%), SE B and C coproducing strains (12.5%), and SE A and C coproducing strains (25.0%). Almost all of the organisms (nine of ten) which were isolated from the feces of patients with MRSA enteritis were SE A and C coproducing strains. The coincidence in time of the prevalence of MRSA enteritis and the isolation SE A and C coproducing strains also demonstrated that these strains caused MRSA enteritis. Although SE C producing strains and SE A and C coproducing strains were simultaneously prevalent in 1990, the former tended to be sensitive while the latter tended to be resistant to minocycline. Considering the variety of antibiotic sensitivity in coagulase type II strains, it is thus considered to be of critical importance for epidemiologic purposes to further characterize isolates by SE typing.

Aged↗

PubMed1993

Mucin-producing pancreatic tumors: a study of nuclear DNA content by flow cytometry.

Nuclear DNA content in eight surgically resected mucin-producing pancreatic tumors (MPPT) consisting of two mucinous intraductal adenocarcinomas (MIDAC), two mucinous intraductal adenomas (MIDA), one mucinous cyst-adenocarcinoma (MCAC), and three mucinous cystadenomas (MCA) were measured by flow cytometry using paraffin-embedded tissue samples. The technique of Shutte was used for the preparation of paraffin-embedded tissue into single dissociated nuclei, while the method of Vindelov was used for staining the isolated nuclei with propidium iodine. Clinicopathologically, the four patients with MIDAC or MIDA were all male and had cystic lesions with a dilated pancreatic duct at the head of the pancreas, while the four patients with MCAC or MCA were all females and had cystic tumors at either the body or tail of the pancreas. All eight patients with MPPT had no metastasis to the regional lymph nodes and were all still alive without recurrence. In an analysis of nuclear DNA content, seven of eight patients had DNA diploid tumors while one patient with a MIDAC perforating the duodenum and choledochus had a DNA aneuploid tumor. Thus, these findings suggest that DNA diploid patterns in MPPT might be associated with a favorable prognosis in MPPT although some patients whose MPPT invaded the surrounding organs might have DNA aneuploid tumors.

Adenocarcinoma, Mucinous↗

PubMed1992

Anomalous arrangement of the pancreaticobiliary ductal system without dilatation of the biliary tract.

A rare case of anomalous arrangement of the pancreaticobiliary ductal system without dilatation of the biliary tract (AAPBDS without DBT) associated with mucosal dysplasia of the biliary duct is described herein. A 53 year old male with a long history of diarrhea and right upper abdominal pain was diagnosed as having AAPBDS without DBT by endoscopic retrograde cholangiopancreatography and other examinations. Excision of the gallbladder and biliary duct with a Roux-en-Y hepatico-jejunostomy was performed and subsequent pathological examination of the surgical specimens showed mucosal hyperplasia of the gall-bladder and mucosal dysplasia of the biliary duct. Considering the dysplastic changes of the biliary duct as seen in our case, and the high incidence of AAPBDS without DBT developing into carcinoma of the biliary duct, being 12.2 per cent, we suggest that pancreaticobiliary ductal diversion with excision of the gallbladder and biliary duct should also be performed for AAPBDS without DBT. However, further pathological investigations concerning the excised biliary duct in AAPBDS without DBT will be need to be carried out.

Bile Ducts↗

PubMed1991

Toxin involvement in methicillin-resistant Staphylococcus aureus enteritis in gastroenterological surgery.

The authors investigated the production of toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxins (SE) by Methicillin-resistant Staphylococcus aureus (MRSA) isolates to clarify the pathogenesis of postoperative MRSA enteritis in patients undergoing gastroenterological surgery. Regarding the percentage of TSST-1 producing strains, there was a significant difference between type II MRSA strains (68.8%) and type IV MRSA strains (4.2%). Among type II strains, all those producing staphylococcal entorotoxin (SE) type C (SEC) also produced TSST-1, although other strains that produced SEB without TSST-1 were commonly isolated. Strains producing SEA were potent producers of SE which was considered to be responsible for enteritis. Therefore, we hypothesized that the strains which produced both SEA and SEC tended to cause enteritis associated with TSS-like symptoms owing to the high titer of these toxins.

Bacterial Toxins↗

PubMed1991

[Study of the host factors in the occurrence of the postoperative infections--special reference to the pathogenicity of the Enterococcus and MRSA].

A study of the pathogenicity of the Enterococcus and Methicillin resistant S. aureus (MRSA) was made of 781 cases with gastroenterological surgery. The results obtained were summarized as follows. In this study 215 strains were isolated from clinical specimens. In these strains 13% was isolated from the postoperative mixed infection and only 7% occurred in single infection. Most of the single infections by the Enterococcus occurred in the cases with changes in host resistance, such as terminal cancer, disorder of the glucose tolerance, malnutrition and/or organ failures. Seventy-three strains were isolated from clinical specimens. In these strains 10% were the postoperative mixed infection and 40% were single infection. Incidence of the infection by the MRSA was significantly high compared with that by the Enterococcus. Single infection by the MRSA occurred even in the cases with normal host resistance. Strains producing enterotoxin C (single or plus A) were frequently isolated in MRSA enteritis or pneumonia. However, 60 percent of the patients in whom MRSA were detected in their abdominal drains had no signs of infection. These results suggest that the occurrence and severity of the MRSA infection relate with site of the infection and production of the exotoxin.

Enterococcus↗