Biomedical subjects

H Hara

Publications and source records attributed to H Hara.

At least 127 records · Page 7Linked to original sources

PubMed2000

Regulation of activator protein-1 activity in the mediastinal lymph node metastasis of lung cancer.

Orthotopic implantation of a metastatic cell line of Lewis lung carcinoma (LLC-MLN), which was isolated by an in vivo selection method, resulted in greater metastatic growth in mediastinal lymph nodes as compared with that of the original LLC cells. LLC-MLN cells also had increased invasive ability and activator protein-1 (AP-1) transcriptional activity as compared with the original LLC cells. This is well consistent with the previously reported finding that overexpression of AP-1 is associated with lymphatic metastasis in lung cancer patients. Oral administration of curcumin, which downregulates AP-1 transcription, significantly inhibited the mediastinal lymph node metastasis of orthotopically implanted LLC cells in a dose-dependent manner, but did not affect the tumor growth at the implantation site. Combined treatment with curcumin and an anti-cancer drug, cis-diamine-dichloroplatinum (CDDP), resulted in a marked inhibition of tumor growth at the implanted site and of lymphatic metastasis, and a significant prolongation of the survival time. The downregulation of transcriptional AP-1 activity by curcumin as seen in the dual luciferase assay caused inhibition of LLC cell invasion through the repression of expression of the mRNAs for urokinase-type plasminogen activator (u-PA) and its receptor (u-PAR). Inhibition of AP-1 transcriptional activity may offer improved therapeutic efficacy for lung cancer patients with lymphatic metastasis.

Animals↗

PubMed2000

Cord blood transplantation and cord blood bank in Japan.

The first cord blood transplantation (CBT) was performed in a 5-year-old boy with acute myelogenous leukemia from his HLA-identical sibling donor in 1994. Since then there have been 17 related and 131 unrelated CBTs in Japan. Overall survival and disease-free survival (DFS) were over 70% in sibling donor CBT. DFS of unrelated CBT in leukemia and other hematological malignancies was 43%, and OS of UCBT in non-malignant diseases was 63%. HLA disparity between the donor and the recipient did not affect the incidence and severity of acute graft-versus-host disease (GVHD) or survival. Cell dose was the most important factor for engraftment and survival both in malignant and in non-malignant diseases. The Japanese government has recently established the nationwide cord blood bank network, and eight local cord blood banks are financially supported by the government. 20,000 units of CB are planned to be collected and stored in the next 5 years by this network.

Blood Banks↗

PubMed2000

Frequencies of CYP2D6 mutant alleles in a normal Japanese population and metabolic activity of dextromethorphan O-demethylation in different CYP2D6 genotypes.

AIMS: To determine the frequencies of 11 CYP2D6 mutant alleles (CYP2D6*2, *3, *4, *5, *8, *10, *11, *12, *14, *17 and *18), and their relation to the metabolic capacity of CYP2D6 in Japanese subjects. METHODS: One hundred and sixty-two unrelated healthy Japanese subjects were genotyped with the polymerase chain reaction amplification method and 35 subjects were phenotyped with dextromethorphan. RESULTS: The frequencies of CYP2D6*2,*5, *10 and *14 were 12.9, 6.2, 38.6 and 2.2% in our Japanese subjects, respectively. CYP2D6*3, *4, *8, *11, *12, *17 and *18 were not detected. The mean log metabolic ratio of dextromethorphan in subjects with genotypes predicting intermediate metabolizers was significantly greater than that of heterozygotes for functional and defective alleles. CONCLUSIONS: CYP2D6*5 and CYP2D6*14 are the major defective alleles found in Japanese subjects. In addition, CYP2D6*10 may play a more important role than previously thought for the treatment of Japanese patients with drugs metabolized by CYP2D6.

Adult↗

PubMed2000

Elevated interleukin (IL)-18 levels during acute graft-versus-host disease after allogeneic bone marrow transplantation.

Acute graft-versus-host disease (aGVHD) after allogeneic bone marrow transplantation (BMT) is mediated by grafted T lymphocytes after their polarization into type 1 T cells. Interleukin (IL)-18, a novel immunoregulatory cytokine, strongly stimulates type 1 T cells, therefore we postulated that IL-18 may be involved in the pathogenesis of aGVHD. Using an enzyme-linked immunosorbent assay (ELISA), we serially measured serum levels of IL-18 in 37 patients with haematological malignancy before and after allogeneic BMT. Patients with aGVHD had high levels of IL-18 that strongly correlated with the severity of aGVHD. We also found that they showed reduced serum levels of IL-18 after appropriate treatment or at a state of resolution. IL-18 levels were not affected by the pretransplant regimen, engraftment or bacterial infection. Compared with circulating interferon (IFN)-gamma or IL-12 levels, serum levels of IL-18 showed a more sensitive and specific correlation with the disease status of aGVHD. These findings suggest that IL-18 may play important roles in the pathogenesis of aGVHD and that measurement of serum IL-18 levels can be useful indicator of aGVHD.

Acute Disease↗

PubMed2000

Interaction of ribosome recycling factor and elongation factor EF-G with E. coli ribosomes studied by the surface plasmon resonance technique.

BACKGROUND: Ribosome recycling factor (RRF), in concert with elongation factor EF-G, is required for disassembly of the post-termination complex of a ribosome after the release of polypeptides. How RRF dissociates the complex has long been puzzling. Crystal structures of RRF molecules have been solved recently and shown to mimic a transfer RNA (tRNA) shape, which prompted us to examine whether RRF binds to the ribosome as tRNA does. RESULTS: The formation of ribosome complexes on the surface-coupled RRF and elongation factor EF-G of Escherichia coli was monitored in real time with a BIACORE 2000 instrument based on the surface plasmon resonance technique. RRF interacted with 70S ribosomes as well as 50S and 30S subunits, although it interacted preferentially with 50S subunits, which was clearly seen under high but physiological ionic conditions. This 50S interaction was diminished by a single amino acid substitutions for Arg132 of RRF, which did not appreciably affect the protein folding but nullified the activity in vivo and in vitro. Moreover, a set of antibiotics that inhibited the RRF-50S interaction were also inhibitory to the polysome breakdown activity of RRF in vitro. The BIACORE technique also worked very well in demonstrating the action of the antibiotics thiostrepton and fusidic acid, which are inhibitory to the RRF function by freezing the pre- and post-translocation intermediates catalysed by EF-G. CONCLUSIONS: These results suggest that the preferential interplay of RRF with the 50S subunit may be of biological significance, probably reflecting the mode of RRF action. The BIACORE technique proved useful for real-time monitoring of the interaction between the ribosome and translation factors, as well as for screening of potential inhibitors for ribosome recycling factor.

Amino Acid Substitution↗

PubMed2000

Differential functionalities of amphiphilic peptide segments of the cell-septation penicillin-binding protein 3 of Escherichia coli.

The class B M1-V577 penicillin-binding protein (PBP) 3 of Escherichia coli consists of a M1-L39 membrane anchor (bearing a cytosolic tail) that is linked via a G40-S70 intervening peptide to an R71-I236 non-catalytic module (containing the conserved motifs 1-3) itself linked via motif 4 to a D237-V577 catalytic module (containing the conserved motifs 5-7 of the penicilloyl serine transferases superfamily). It has been proposed that during cell septation the peptidoglycan crosslinking activity of the acyl transferase module of PBP3 is regulated by the associated M1-I236 polypeptide itself in interaction with other components of the divisome. The fold adopted by the R71-V577 polypeptide of PBP3 has been modelled by reference to the corresponding R76-S634 polypeptide of the class B Streptococcus pneumoniae PBP2x. Based on these data and the results of site-directed mutagenesis of motifs 1-3 and of peptide segments of high amphiphilicity (identified from hydrophobic moment plots), the M1-I236 polypeptide of PBP3 appears to be precisely designed to work in the way proposed. The membrane anchor and the G40-S70 sequence (containing the G57-Q66 peptide segment) upstream from the non-catalytic module have the information ensuring that PBP3 undergoes proper insertion within the divisome at the cell septation site. Motif 1 and the I74-L82 overlapping peptide segment, motif 2 and the H160-G172 overlapping peptide segment, and the G188-D197 motif 3 are located at or close to the intermodule junction. They contain the information ensuring that PBP3 folds correctly and the acyl transferase catalytic centre adopts the active configuration. The E206-V217 peptide segment is exposed at the surface of the non-catalytic module. It has the information ensuring that PBP3 fulfils its cell septation activity within the fully complemented divisome.

Amino Acid Motifs↗

PubMed2000

Pulmonary adenocarcinoma with heterotopic bone formation.

Adenocarcinoma of the lung is a common malignancy. Frequently, this tumor can cause calcification within a primary tumor. However, an extremely rare occurrence in lung carcinomas is ossification within a primary tumor, and to our knowledge only three cases have been reported. We report a case of pulmonary adenocarcinoma with ossification, and discuss the pathogenesis of intratumoral ossification with a review of the literature.

Adenocarcinoma↗

PubMed2000

Intestinal fat suppresses protein-induced exocrine pancreatic secretion in chronically bile-pancreatic juice-diverted rats.

Previously, we showed that the increase in pancreatic enzyme secretion was lower after feeding a casein diet containing fat than that after feeding a fat-free casein diet in chronically bile-pancreatic juice (BPJ)-diverted rats. In the present study, we determined whether the suppressive effects of fats on flow volume of BPJ and pancreatic enzyme secretion depend on delaying gastric emptying and examined the characteristics of the suppression with intraduodenal instillation of soybean oil or lecithin in BPJ-diverted rats. The study was conducted as three separate experiments using conscious rats with chronic BPJ diversion by means of a common bile-pancreatic duct catheter. The flow volume of BPJ and the secretion of pancreatic amylase and trypsin were determined after intraduodenal instillation of the test solution. Exocrine pancreatic secretion was strongly stimulated by administration of guanidinated casein hydrolysate (HGC, 150 mg/ml) in chronic BPJ-diverted rats. However, pancreatic secretion after administration of an emulsion containing HGC with either soybean oil (100 mg/ml) or mixed fat (50 mg/ml soybean oil + 50 mg/ml lecithin) was much lower than that after administration of HGC alone. In contrast, administration of the soybean oil emulsion without HGC resulted in a small, but significant increase in the volume of BPJ. The suppressive effects of soybean oil (100 mg/ml) on the increases in the BPJ flow and enzyme secretion were similar to those of sodium taurocholate (10 mg/ml), and there was no additive effect of soybean oil on taurocholate suppression. In conclusion, duodenally instilled soybean oil suppressed increases in flow volume of BPJ and pancreatic enzyme secretion induced by HGC in chronic BPJ-diverted rats, showing that the suppressive effect of the fat does not depend on delaying gastric emptying.

Animals↗

PubMed2000

Timing of lowest and highest peak expiratory flow in patients with asthma: influence of anti-inflammatory treatment.

We sought to determine the optimal time for measuring peak expiratory flow rate (PEF) in patients with mild to moderate asthma, before and after treatment with inhaled beclomethasone dipropionate (BDP). After 2 weeks of observation, BDP (400 microg/d) was given to 22 patients with mild to moderate asthma. The dose of BDP (800-1200 microg/d) was increased every 2 weeks until PEF varied by no more than 20% each day. PEF was measured four times daily: on awakening, around noon, in the evening and at bedtime. Significant (P < 0.05) rhythms were detected by single cosinor analysis in all patients, both during observation and during treatment. Analysis by the population mean-cosinor method showed that the mean mesor was 378.8+/-59.1 lmin(-1), the mean amplitude was 53.9+/-13.4 lmin(-1), and the mean acrophase was at 16:26+/-0:32 before treatment. After treatment, the mean mesor was 528.0+/-61.9 l min(-1), the mean amplitude was 37.6+/-12.2 lmin(-1), and the mean acrophase was at 16:35+/-0:32. The mesor increased significantly (P<0.05), and the amplitude decreased significantly (P<0.05) after treatment. The acrophase did not change. These data indicate that PEF is lowest at 04:30 and highest at 16:30 in patients with mild to moderate asthma, both during observation and during treatment. We conclude that if one needs to assess PEF twice a day, this should ideally be done at 04:30 and 16:30, not only before but also after treatment with BDP.

Adolescent↗

PubMed2000

Inhibitory effect of nitric oxide on the induction of cytochrome P450 3A4 mRNA by 1,25-dihydroxyvitamin D3 in Caco-2 cells.

Cytochrome P450 (CYP)-dependent drug metabolism decreases in vivo and in cultured hepatocytes under various immunostimulatory conditions. Nitric oxide (NO) released during inflammation is presumed to be involved in this phenomenon. CYP3A4, which is abundant in the liver and small intestine and participates in the metabolism of various drugs, is known to be induced by 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in the colon carcinoma cell line Caco-2. In this study we examined whether NO affected CYP3A4 gene expression induced by 1,25(OH)2D3 in Caco-2 cells. Induction of CYP3A4 mRNA by 1,25(OH)2D3 was suppressed in a dose-dependent manner by treatment with the NO donors NOR-4 (15-500 microM) or S-nitroso-N-acetylpenicillamine (30 microM-1 mM), which spontaneously release NO. These results indicated that NO has an inhibitory effect on the induction of CYP3A4 mRNA by 1,25(OH)2D3 in Caco-2 cells. Treatment with the guanylate cyclase inhibitor ODQ failed to prevent the inhibition of induction of CYP3A4 mRNA by 1,25(OH)2D3. 8-Bromo cGMP had no effect on 1,25(OH)2D3-induced CYP3A4 gene expression. Therefore, the suppression of CYP3A4 mRNA by NO might be mediated through a guanylate cyclase-independent pathway.

Caco-2 Cells↗

PubMed2000

Contribution of the cecum and colon to zinc absorption in rats.

We examined the role of the large intestine in zinc absorption in rats in three separate experiments. In the first experiment, we examined apparent zinc absorption in rats fed diets containing graded levels of zinc carbonate (0.015-0.535 mmol Zn/kg diet) and evaluated zinc status on the basis of the zinc concentrations in serum and several tissues. The zinc absorption and the serum zinc concentration increased with the zinc content of the diet up to 0. 153 mmol Zn/kg diet. Femoral and pancreatic zinc levels increased linearly up to 0.229 mmol Zn/kg diet. In the second experiment, a zinc carbonate suspension was administered into the cecum via an implanted cannula or into the stomach via an orogastric tube, and the rats were fed diets with or without a highly fermentable fiber, guar gum hydrolysate (GGH, 50 g/kg diet), with coprophagy prevention. The amount of instilled zinc corresponded to the amount of zinc ingested as a component of the diet by the rats of a control group, 0.229 mmol Zn/kg diet. Apparent absorption of cecally instilled zinc was approximately half that observed when zinc was administered into the stomach in both diet groups. Serum and femur zinc concentrations in the cecum-administered groups were approximately 50 and 25% lower, respectively, than those in rats administered zinc into the stomach. The results demonstrate that, in vivo, the absorptive efficiency in the large intestine is not sufficient to satisfy the rat's zinc requirement and does not change when the luminal environment is substantially altered by feeding GGH. In Experiment 3, the effects of cecocolonectomy on zinc absorption were examined in rats with gastric acid suppression. In the cecocolonectomized groups, serum zinc concentration was lower as a result of treatment with a proton pump inhibitor, omeprazole, than in vehicle-treated rats, but not in sham-operated groups. These findings suggest that the cecum and colon contribute to zinc absorption when absorption in the small intestine is impaired.

Analysis of Variance↗

PubMed2000

The cecum and dietary short-chain fructooligosaccharides are involved in preventing postgastrectomy anemia in rats.

Dietary short-chain fructooligosaccharides (Sc-FOS) stimulate absorption of calcium and magnesium in the large intestine of rats. In this study, we examined whether Sc-FOS stimulate iron absorption in the large intestine by monitoring recovery from anemia in gastrectomized rats, with or without cecectomy. The rats were divided into four groups, i.e., sham-operated (Sham), gastrectomized only (GX), cecectomized only (CX) and both gastrectomized and cecectomized (GCX). Half of the rats in each group were fed a control diet (AIN-93G) and the other half were fed a Sc-FOS-containing diet (75 g/kg diet) for 28 d. Hematocrit (Ht) and hemoglobin concentration (Hb) were measured at the start, and on d 14 and 28 after the start of feeding. On the final day of the study, total blood was collected. Gastrectomy significantly decreased Ht and Hb, but cecectomy did not influence these variables. Dietary Sc-FOS prevented the decrease in Ht and Hb significantly. In the gastrectomized rats, the effectiveness of Sc-FOS in preventing postgastrectomy anemia was significantly diminished by cecectomy. These results suggest that the effect of Sc-FOS in increasing absorption of iron in gastrectomized rats takes place in part in the cecum. The cecum plays an important role in the mechanism by which Sc-FOS prevent postgastrectomy anemia.

Analysis of Variance↗

PubMed2000

Dietary sugar beet fiber prevents the increase in aberrant crypt foci induced by gamma-irradiation in the colorectum of rats treated with an immunosuppressant.

We demonstrated recently that gamma-irradiation can induce aberrant crypt foci (ACF) in the rat colorectum. The aim of this study was to evaluate the effect of dietary sugar beet fiber (SBF) on the distribution of the CD8(+) intraepithelial lymphocyte (IEL) in the colorectum and on the number of gamma-irradiation-induced ACF of rats administered anti-asialo GM1 (alpha AGM1) as an immunosuppressant. Wistar/ST rats fed a fiber-free diet or the diet supplemented with SBF (100 g/kg diet) were administrated alpha AGM1 or normal rabbit serum as a control during the initiation period with gamma-irradiation. At 5 and 9 wk after the first irradiation, ACF and total aberrant crypts (AC) per area in the colorectum were counted. The numbers of ACF (P = 0.0010) and AC (P = 0.0635) per unit area were lower in the SBF-fed group than in the rats fed the fiber-free diet. alpha AGM1 administration significantly raised the number of ACF (P = 0.0001) and AC (P = 0.0006) per area in the colorectum. Moreover, alpha AGM1 administration during the initiation period reduced the number of CD8(+) IEL per 100 cells in the epithelial layer (P = 0.0001) of the colon. These results demonstrate that reduction of the number of CD8(+) IEL per 100 cells in the epithelial layer as a result of alpha AGM1 administration promotes the formation of irradiation-induced ACF in the colorectum. The number of CD8(+) IEL per 100 cells in epithelial layer was lower in the group fed the fiber-free diet than in the SBF-fed group (P = 0.0522). These results indicated that the ingestion of dietary SBF suppressed gamma-irradiation-induced ACF formation through the immune surveillance in the colorectal mucosa.

Animals↗

PubMed2000

Calcium concentration in hepatocytes during liver ischaemia-reperfusion injury and the effects of diltiazem and citrate on perfused rat liver.

OBJECTIVE: To clarify the role of the calcium concentration in hepatocytes in liver ischaemia-reperfusion injury in relation to the protective effect of calcium-related agents. DESIGN: Serial calcium concentrations of extramitochondrial cytosolic sites (EMCa) and in mitochondria (MCa) in hepatocytes of isolated perfused rat liver were measured by an electron probe X-ray microanalyser, and the effects of calcium-related agents were evaluated. METHODS: Ischaemia was induced for 2 h, followed by 2 h of reperfusion in group I (without drug), group II (with diltiazem, 9.3 microM) and group III (with citrate, 5 mM). RESULTS: In group I, EMCa increased rapidly after reperfusion (before ischaemia, 2.0 mmol/kg wet weight; 1 min after reperfusion, 4.4 mmol/kg), and MCa increased (before ischaemia, 2.6 mmol/kg; 1 min after reperfusion, 5.07 mmol/kg). Thereafter the levels decreased, but remained high at 120 min after reperfusion in group I (EMCa, 3.2 mmol/kg, MCa 4.1 mmol/kg). At 1 min after reperfusion, EMCa in group III (2.9 mmol/kg) and MCa in groups II (3.4 mmol/kg) and III (4.0 mmol/kg) were significantly lower than in group I. At 120 min after reperfusion, the EMCa and MCa in groups II (2.5 and 3.1 mmol/kg, respectively) and III (2.4 and 3.0 mmol/kg, respectively) remained at significantly lower levels. Mitochondrial function in groups II and III was better preserved than in group I. The levels of hepatic enzymes in the perfused fluid of group III were lower than in group I. CONCLUSIONS: Calcium concentration in hepatocytes may play an important role in ischaemia-reperfusion injury. Diltiazem and citrate demonstrated a protective effect by maintaining a low calcium level in hepatocytes.

Adenosine Triphosphate↗

PubMed2000

Cell surface-associated enolase in Actinobacillus actinomycetemcomitans.

Cell surface-associated materials of Actinobacillus actinomycetemcomitans were extracted by a short incubation of the cell suspension in a Tris-buffered saline in the presence and absence of a restriction enzyme, EcoRI. The supernatants (which we termed EcoRI extract and surface extract, respectively) contained a number of extracellularly released proteins. Of these proteins, four major proteins were identified by N-terminal sequencing to be the 34 and 39 kDa outer membrane proteins, the GroEL-like protein, and a 47 kDa protein homologous to Haemophilus influenzae enolase. Enolase activity was found in the extracts and its relative amount of activity in the EcoRI extract from a culture of the mid-exponential growth phase was estimated as 5.7% of total enzyme activity. In contrast, the relative amount of activity of another cytosolic enzyme, lactate dehydrogenase, was extremely low in the extracts and also in the culture supernatant. These results suggest the external localization of enolase in this bacterium.

Aggregatibacter actinomycetemcomitans↗

PubMed2000

[The efficacy of influenza vaccine among geriatric inpatients].

To investigate the efficacy of influenza vaccine in the elderly, hemagglutination inhibition (HI) antibody titer for the three types of influenza viruses were measured and the influenza infection rate was determined serologically in geriatric inpatients. Influenza vaccination was done for inpatients. For patients who had influenza vaccination in the year prior to the study, influenza vaccine was administered once or twice, and the number of injections were determined randomly. Influenza vaccine was injected twice to those had not received influenza vaccine in the previous year. Serum samples were collected from 166 vaccinated and 104 unvaccinated patients before and after 1996/1997 influenza season. In the vaccinees who had been vaccinated the previous year, 56 patients were injected once and 58 patient were injected twice. Fifty-two patients had not been vaccinated the previous year. Serologically diagnosed influenza infection rate in the 104 unvaccinated patients was 16.3% for influenza A/H3N2 and 8.7% for influenza B. The infection rate was 3.0% for influenza A/H3N2 and 0.6% for influenza B in the 166 vaccinated patients. The infection rates were significantly lower in the vaccinees than in the unvaccinated patients (p < 0.001 with A/H3N2 and p < 0.01 with B). There was no significant difference in the infection rate among the three vaccinated groups. These results suggest that the influenza vaccination had significant protective efficacy for influenza infection in the elderly. Prior vaccination did not diminish the efficacy of the influenza vaccine. The efficacy of a single influenza vaccine injection was equivalent to that of two injection.

Aged↗

PubMed2000

[The clinical feature of febrile episodes].

Institutionalized elderly patients are at risk of nosocomial infection because of their compromised status by aging. To clarify the relationship between fever and disease in elderly patients, we analyzed 1,105 febrile episodes, the etiology of which were already diagnosed, of 443 patients (136 men, 307 women). All patients who were 65 years of age or older and who had been admitted to the hospital for more than 7 days had fevers above 37.5 degrees C recorded. The etiologies of the 1,105 febrille episodes were respiratory tract infection in 381 (34.5%), urinary tract infection in 263 (23.8%), other diseases in 164 (14.8%) and in 297 (26.9%) unknown. The episodes were categorized into two groups by the degree of initial fever: group A, 559 episodes (50.6%) of 37.5-38.0 degrees C and group B, 546 episodes (49.4%) of above 38.0 degrees C. Of the episodes, 41.0% were one-day fevers, 21.4% two-day fevers, and 14.0% three-day fevers. The frequency of two-or-more-day fevers was significantly higher in group B (69.0%) than in group A (49.2%) (p < 0.001). In group B, respiratory tract infection (44.3%) was more frequent than urinary tract infection (16.1%) (p < 0.001). Of the respiratory tract infections, 63.5% were in group B and, in contrast, 66.5% of the urinary tract infections were in group A. The white blood cell count and C-reacting protein levels were significantly higher in group B than in group A (p < 0.001). The degree of initial fever is an important predictive marker of severity of disease in elderly patients.

Aged↗

PubMed2000

[Amantadine usage for influenza A during an influenza outbreak in a nursing home].

An outbreak of an influenza like illness was found in a nursing home in Fukuoka in January, 1999. Results of hemagglutinin inhibition tests with paired sera of patients and rapid diagnosis kit for influenza A indicated that an influenza A (H3N2) outbreak had occurred. A total of 15 patients with influenza like illness from one residential area of the nursing home were administered amantadine, 100 mg per day for five days. Clinical records of 264 residents were surveyed retrospectively from the tenth to the thirty-first of January, 1999. Influenza like illness was found in 112 residents (42.4%). The incidence of influenza like illness differed by residential area, ranging from 27.6% to 54.0%. The mean duration of fever was 3.6 days among patients administered amantadine. The mean duration was 4.4 days for patients not administered amantadine. The incidence of influenza like illness decreased rapidly after amantadine administration in the residential area where amantadine administration was done. These results suggest that amantadine is effective in mitigating influenza symptoms in the elderly. Amantadine may be useful for diminishing the influence of influenza A outbreaks in nursing homes.

Aged↗