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Biomedical subjects

Y Yagi

Publications and source records attributed to Y Yagi.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Clinical and serological study of tsutsugamushi disease in northern Osumi, Kagoshima Prefecture].

We report 34 cases of tsutsugamushi disease seen from 1989 to 1993 at Yagi Clinic, northern Osumi, Kagoshima Prefecture. Nineteen patients (55.9%) showed the highest antibody titers against the Kawasaki strain Orientia tsutsugamushi (Ot) and 13 (38.2%) against the Kuroki strain Ot. It is suggested that two antigenic types (Kawasaki and Kuroki) of Ot were distributed in Kagoshima Prefecture, and the Kawasaki type Ot more or less dominates Kuroki type Ot. There was no difference in clinical features between the two groups of patients.

Adolescent↗
PubMed1997

[A case of hemolytic uremic syndrome documented co-infection of vertoxin producing Escherichia coli O157 and other pathogens].

We reported a case of a 3-year-old girl with hemolytic uremic syndrome (HUS), which showed hemolytic anemia (Hemoglobin 8.2 g/dl, lactate dehydrogenase 1277 IU/l and total bilirubin 0.6 mg/dl), small purpura on the skin (platelet 7.3 x 10(4)/microliter) and slightly decreased output of urine (creatinine 0.4 mg/dl and blood urea nitrogen 27.2 mg/dl). Verotoxin producing Escherichia coli (E. coli) O157 was not isolated, but Salmonella agona and E. coli O125, which is one of the enteropathogenic E. coli, were detected from her stool culture. However, the IgM antibody against verotoxin producing E. coli (VTEC) O157 lipopolysaccharide was detected in both serum of the acute and convalescent phase by immunoblot assay. In addition verotoxin DNA was demonstrated in the stool by PCR method. Therefore, we think this HUS might be due to VTEC O157, which must have been co-infected with Salmonella agona and E. coli O125. There have been four cases including the present case of co-infection with VTEC O157 so far, and the other three cases were of the Salmonella species. Although the reason of co-infection was unknown, we may infer that food might be contaminated with some pathogens including Salmonella species or that these patients might be already infected with Salmonella species prior to VTEC infection. Even when some other pathogens were detected by a stool culture from a patient with HUS, we should pay attention to demonstrate associated of VTEC and HUS by the specific antibodies and PCR for verotoxin DNA.

Child, Preschool↗
PubMed1997

Electrocardiographic nature of restored sinus rhythm after Cox maze procedure in patients with chronic atrial fibrillation who also had other cardiac surgery.

OBJECTIVE: To characterise heart rate variability and high frequency components of restored sinus rhythm after the maze procedure. The maze procedure for chronic atrial fibrillation may prevent thrombotic events and improve the quality of life. However, the electrocardiographic nature of restored sinus rhythm after the maze procedure has not been fully elucidated. PATIENTS AND METHODS: Between March 1993 and August 1995, 104 consecutive patients undergoing the maze procedure in combination with other cardiac surgery were studied. There were 100 long-term survivors (78 with mitral valve disease, 9 with aortic valve disease, 8 with congenital heart disease, and 5 others). Twenty age-matched patients with mitral valve disease who were in normal sinus rhythm preoperatively were enrolled as a control group. 30 days after surgery, the presence of arrhythmias and the circadian changes of heart rate variability were estimated by ambulatory electrocardiographic monitoring and the filtered P duration was evaluated by signal-averaged electrocardiogram. RESULTS: Restoration of sinus rhythm was observed in 73 of 100 cases. Subjects were classified into three groups according to their postoperative ambulatory electro-cardiographic monitoring findings: patients in group 1 (n = 73) (1a: 58 regular sinus rhythm; 1b: 15 sinus rhythm with frequent premature atrial contractions (> 1000/day); patients in group 2 (n = 21) still had persistent atrial fibrillation; and patients in group 3 (n = 6) required permanent pacemaker implantation because of sick sinus syndrome. The success rate of restoration of sinus rhythm was 88.3% if left atrial diameter was small (< 65 mm). Circadian changes in the low frequency to high frequency power ratio in group 1a were significantly diminished compared with control group (P < 0.01). Furthermore, the filtered P duration in group 1a (150 (20) ms) and group 1b (158 (23) ms) were longer than in the control group (122 (11) ms) (P < 0.01). CONCLUSIONS: The maze procedure may result in a decreased sinus response and non-uniform transmission of impulses in the atrium.

Adult↗
PubMed1997

Mechanism of posturally induced crackles as predictor of latent congestive heart failure.

We investigated the role of changes in pulmonary function in posturally induced crackles (PIC) in 76 patients with various heart diseases. Regional ventilation was evaluated by spirometric gated ventilation scanning using 133Xe in 23 of these patients and its relationship to PIC was analyzed. A change from the sitting to the supine position was associated with a significant decrease in the percent functional residual capacity (FRC, p < 0.01) and significant increases in closing volume (CV), CV/vital capacity (VC) and closing capacity (CC)/FRC (p < 0.01) in the PIC-positive subjects. CV, CV/VC and CC/FRC did not differ significantly between PIC-positive (n = 37) and PIC-negative (n = 39) subjects in the sitting position, but in the supine position, these values were significantly higher in the PIC-positive group than in the PIC-negative group (CV: p < 0.05, CV/VC and CC/FRC: p < 0.01). These results suggest that airway closure was markedly increased in PIC-positive subjects in the supine position compared with PIC-negative subjects. Regional ventilation (V) was assessed in the sitting and the supine position from right lateral images divided into 9 segments from the base to the apex of the lung using spirometric gated ventilation scanning. There was no significant difference in regional ventilation in the sitting position between PIC-negative (n = 11) and PIC-positive (n = 12) subjects; in the supine position, regional ventilation decreased significantly at the base in the PIC-positive group. Findings suggest that PIC at the base of the lungs may be related to airway closure at the base of the lungs in the supine position in PIC-positive subjects.

Adult↗
PubMed1997

Assessment of right ventricular contractile function in patients with left ventricular dysfunction by a simplified echocardiographic subtraction method.

A simplified version of the modified echocardiographic subtraction method for measuring right ventricular (RV) volume was used to assess the indices of RV contractile function, the end-systolic pressure-volume (RV Emax) ratio and the +dP/dt(max)-end-diastolic volume (EDV) relationship. RV volumes determined by the simplified subtraction method and the modified subtraction method were compared in 18 patients. Subsequently, RV contractile function was assessed in 13 patients with normal left ventricular (LV) function (control group: ejection fraction > 56%, as determined by left ventriculography), and 10 patients (group F; five with myocardial infarction, three with dilated cardiomyopathy, two with ischemic cardiomyopathy) with depressed LV function (ejection fraction < or = 55% by left ventriculography). During the application of lower body negative pressure of -20 mmHg, B-mode echocardiograms (apical four-chamber view) and RV or pulmonary artery pressure were recorded simultaneously. The regression equation between RV volumes obtained by the simplified subtraction method and the modified subtraction method was y = 0.99x + 4.5, and the correlation coefficient (r) was 0.985 (p < 0.001). The RV Emax of group F was not significantly less than that of the control group (0.40 +/- 0.16 vs 0.44 +/- 0.17 mmHg/ml, not significant). The correlation coefficients of RV Emax in each group were large (control group 0.92 +/- 0.09, group F 0.90 +/- 0.07). The +dP/dtmax-EDV ratio of group F was significantly less than that of the control group (2.05 +/- 0.74 vs 3.40 +/- 1.85 mmHg/ml.sec, p < 0.05). The correlation coefficient of the +dP/dtmax-EDV ratio was 0.91 +/- 0.06 in the control group and 0.85 +/- 0.15 in group F. The indices of RV contractile function could be assessed using the simplified subtraction method. RV function in patients with LV dysfunction appeared to be depressed.

Adult↗
PubMed1997

Can the maze procedure be combined safely with mitral valve repair?

BACKGROUND AND AIMS OF THE STUDY: The safety of combining mitral valve repair with the maze procedure for chronic atrial fibrillation in the surgical management of patients with mitral valve disease is not well elucidated. We present our operative results regarding mortality and morbidity after such combined surgery. As a comparison, our operative results after mitral valve repair in patients without chronic atrial fibrillation are presented. METHODS: Between April 1993 and December 1994, 39 patients with chronic atrial fibrillation underwent mitral valve repair and concomitant maze procedure (group 1) at the Iwate Medical University. During the same period, 36 patients with sinus rhythm and one patient with DDD pacemaker underwent mitral valve repair (group 2). In order to evaluate the operative risk, morbidity, and mortality of adding the maze procedure to mitral valve repair, total cardiopulmonary bypass time, aortic cross-clamp time, intraoperative blood loss, intubation period, and duration of ICU stay were compared between the groups. RESULTS: Total cardiopulmonary bypass time and aortic cross-clamp time in group 1 were longer than in group 2 (174.0 +/- 38.8 min versus 150.1 +/- 54.4 min; p = 0.032, 122.5 +/- 30.7 min versus 95.8 +/- 38.2 min; p = 0.0012). However, the duration of ICU stay, intubation period, and intraoperative blood loss were not different between the groups. There were no hospital deaths in either group. Four patients in group 1, and two patients in group 2 required re-exploration for bleeding (p = NS). Two patients in group 1, and none in group 2 required pacemaker implantation postoperatively (p = NS). Two patients in group 2, and none in group 2 had minor cerebral infarction (p = NS). At hospital discharge, 28 patients in group 1 (72%) and 35 patients (97%) in group 2 were in sinus rhythm. CONCLUSIONS: The maze procedure can be combined with mitral valve repair without adding undue operative risk to patients. Those patients with chronic atrial fibrillation undergoing mitral valve repair may be advised for the possibility of concomitant maze procedure.

Aged↗
PubMed1997

Effects of artificial tear temperature on corneal sensation and subjective comfort.

PURPOSE: Cooling reduces acute inflammation and local nerve sensation. We investigated the relationship between artificial tear temperature, ocular surface sensation, and patient comfort. METHODS: We placed preservative-free artificial tears and eye mask stored at four temperatures (36 degrees C, 25.2 degrees C, 4 degrees C, and -10 degrees C) in the right eyes of 24 normal subjects, whose left eyes served as controls. Corneal and conjunctival sensations were measured and corneal temperature was recorded. Comfort was reported on a 7-point scale. RESULTS: Corneal temperature was significantly lowered with all temperature artificial tears and frozen eye mask (p < 0.001 for each temperature relative to the previous one). Aesthesiometer readings were inversely correlated with corneal temperature (r = -0.45, p = 0.0005), decreasing with lower temperatures, reaching 2.0 +/- 1.3 g/mm2 (p = 0.001) for the mask. Conjunctival sensation reacted similarly and was well correlated with both corneal temperature (r = 0.43, p = 0.0009) and corneal sensation (r = 0.39, p = 0.006). Treatments provided relief, with the 4 degrees C tears being the most comfortable (p = 0.0001). CONCLUSION: Although there may still be some biases, cooled artificial tears provide relief to the eye by the mechanism of reduced corneal and conjunctival sensation.

Administration, Topical↗
PubMed1997

[Cytokine-secreting cells in relapsing multiple sclerosis patients treated with high-dose intravenous methylprednisolone].

Interleukin-2 (IL-2), interleukin-2 receptor (IL-2R), interferon gamma (INF gamma), interleukin-4 (IL-4) secreting peripheral blood cells were enumerated by enzyme-linked immunospot (ELISPOT) assay in 9 relapsing multiple sclerosis (MS) patients treated with high-dose intravenous methylprednisolone (MP), in 7 MS patients with remission,and in 9 controls. IL-2, IL-2R, INF gamma, IL-4 secreting cells were significantly higher before MP therapy in relapsing MS patients as compared with after MP therapy in relapsing MS patients, with MS patients in remission, and with controls. IL-2, INF gamma secreting cells before MP in relapsing MS patients and those in remission significantly increased in response to myelin basic protein (MBP) 4-14, 68-84 and proteolipid protein (PLP). INF gamma secreting cells after MP therapy in relapsing MS patients significantly increased in response to MBP 4-14, 68-84, and PLP. IL-2R secreting cells in MS patients in remission significantly increased in response to MBP 4-14, 68-84, and PLP and were significantly higher after MP therapy in relapsing MS patients and in controls. This fact suggested that there was a systemic T-cell response to myelin antigens in MS patients in remission. The use of ELISPOT to investigate cytokine-secreting cells may play a role in the evaluation of clinical activity during treatment with high-dose intra-venous MP in relapsing MS patients.

Adult↗
PubMed1996

Synthesis and bioactivity of novel bis(heteroaryl)piperazine (BHAP) reverse transcriptase inhibitors: structure-activity relationships and increased metabolic stability of novel substituted pyridine analogs.

The major route of metabolism of the bis(heteroaryl)piperazine (BHAP) class of reverse transcriptase inhibitors (RTIs), atevirdine and delavirdine, is via oxidative N-dealkylation of the 3-ethyl- or 3-isopropylamino substituent on the pyridine ring. This metabolic pathway is also the predominant mode of metabolism of (alkylamino)piperidine BHAP analogs (AAP-BHAPs), compounds wherein a 4-(alkylamino)piperidine replaces the piperazine ring of the BHAPs. The novel AAP-BHAPs possess the ability to inhibit non-nucleoside reverse transcriptase inhibitor (NNRTI) resistant recombinant HIV-1 RT and NNRTI resistant variants of HIV-1. This report describes an approach to preventing this degradation which involves the replacement of the 3-ethyl- or 3-isopropylamino substituent with either a 3-tert-butylamino substituent or a 3-alkoxy substituent. The synthesis, bioactivity and metabolic stability of these analogs is described. The majority of analogs retain inhibitory activities in enzyme and cell culture assays. In general, a 3-ethoxy or 3-isopropoxy substituent on the pyridine ring, as in compounds 10, 20, or 21, resulted in enhanced stabilities. The 3-tert-butylamino substituent was somewhat beneficial in the AAP-BHAP series of analogs, but did not exert a significant effect in the BHAP series. Lastly, the nature of the indole substitution sometimes plays a significant role in metabolic stability, particularly in the BHAP series of analogs.

Anti-HIV Agents↗
PubMed1996

Targeting delavirdine/atevirdine resistant HIV-1: identification of (alkylamino)piperidine-containing bis(heteroaryl)piperazines as broad spectrum HIV-1 reverse transcriptase inhibitors.

A novel class of bis(heteroaryl)piperazine (BHAP) analogs which possesses the ability to inhibit NNRTI (non-nucleoside reverse transcriptase inhibitor) resistant recombinant HIV-1 reverse transcriptase (RT) and NNRTI resistant variants of HIV-1 has been identified via targeted screening. Further investigation of the structure-activity relationships of close congeners of these novel (alkylamino)piperidine BHAPs (AAP-BHAPs) led to the synthesis of several compounds possessing the desired phenotype (e.g., activity against recombinant RTs carrying the Y181C and P236L substitutions). Further structural modifications were required to inhibit metabolism and modulate solubility in order to obtain compounds with the desired biological profile as well as appropriate pharmaceutical properties. The AAP-BHAPs with the most suitable characteristics were compounds 7, 15, and 36.

Animals↗
PubMed1996

Assessment of autonomic nervous function by power spectral analysis of heart rate variability in the horse.

We studied power spectral analysis of heart rate (HR) variability in the horse, with the hypothesis that the quantitative information provided by the spectral analysis of HR variability reflects the interaction between sympathetic and parasympathetic regulatory activities. For this purpose, electrocardiogram, blood pressure (BP) and respiratory (Resp) waveform were simultaneously recorded from Thoroughbred horses (3-5 years old) and analyzed by power spectrum. There were two major spectral components at low-frequency (LF) and high-frequency (HF) bands for HR variability. The peak of Resp variability clearly occurred at the HF range. In contrast to Resp variability, the power spectra of BP variability occurred at lower frequencies. The maximum coherence between HR and Resp variabilities and HR and BP variabilities occurred at approximately 0.15 and approximately 0.03 Hz, respectively. These relationships were similar to the ensemble spectra. On the basis of these data, we have defined two frequency bands of interest: LF (0.01-0.07 Hz) and HF (0.07-0.6 Hz). Therefore, we believe that power spectral analysis of HR variability provides a very powerful technique for assessing autonomic nervous activity in the horse.

Animals↗
PubMed1996

Alteration of T cells and natural killer cells during chickenpox in infancy.

To determine the reasons for the low immune response and the mild morbidity of chickenpox in infancy, we investigated alteration of T cells and natural killer (NK) cells during chickenpox in children < 1 year and > or = 2 years old using flow cytometry. The CD4/CD8 ratio decreased only in the < 1-year-old group from the acute to the convalescent phase (P < 0.05). The CD3-CD16+CD56+ and CD57-CD16+ counts increased in the < 1-year-old group, but those in the > or = 2-year-old group did not increase from the acute to the convalescent phase. The CD3-CD16+CD56+ counts and the CD57-CD16+ counts and percentage were larger in the < 1-year-old group than those in the > or = 2-year-old group (P = 0.001, P = 0.002, and P < 0.05) in the convalescent phase. These results seem to indicate that the low immune response in infancy after chickenpox are related to the small number of CD8 in contrast with CD4 and that increased subsets of NK cells during chickenpox may correlate to the mild morbidity of chickenpox in infancy.

Acute Disease↗
PubMed1996

Effects of diclofenac eye drops on corneal epithelial structure and function after small-incision cataract surgery.

PURPOSE: To investigate prospectively the effect of diclofenac sodium (DfNa) eye drops on corneal epithelial structure and function. METHODS: Seventeen patients with bilateral age-related cataract undergoing phacoemulsification combined with intraocular lens implantation were studied prospectively. After the surgery on both eyes, one eye each of these patients was assigned randomly to receive 0.1% DfNa eye drops three time daily (DfNa group), and the other eye served as control (control group). Vital stainings, tear function test, corneal sensitivity measurement, specular microscopy for corneal epithelium and endothelium, pachymetry, anterior fluorometry to measure epithelial barrier function, and laser flare-cell-metry were performed before and after surgery. RESULTS: There were no statistically significant differences between the DfNa and control groups in any measurement examined except for laser cell-flare-metry, in which the DfNa group demonstrated a significantly lower flare value at day 7 postoperatively (compare with the preoperative level of 73% +/- 41% in the DfNa group, and 130% +/- 98% in the control group, P=0.035). Epithelial cells in the DfNa group showed slight elongation and increased permeability postoperatively; however, there were no statistically significant differences with the control group. CONCLUSIONS: Administration of DfNa eye drops did not cause significant abnormalities in the corneal epithelial structure or function of patients who had undergone small-incision cataract surgery. Their safety for use in procedures such as excimer laser photorefractive keratectomy remains to be established.

Aged↗
PubMed1996

Decrease in corneal sensitivity and change in tear function in dry eye.

Our purpose was to investigate the relationship between insufficient tear secretion and decreased corneal sensitivity. We studied 59 patients with dry eye, 15 of whom had Sjögren's syndrome (SS), and 26 healthy subjects. Corneal sensitivity was measured by the esthesiometer of Cochet and Bonnet. Schirmer test with or without anesthesia, tear clearance rate, tear function index, and rose bengal and fluorescein staining were also evaluated. The mean corneal sensitivity of either dry-eye group (4.6 +/- 1.2 and 4.5 +/- 1.2 cm for non-SS and SS dry eye, respectively) was significantly lower than that of the control (5.8 +/- 0.4 cm, p < 0.001). Corneal sensitivity correlated significantly with the Schirmer values with anesthesia and the tear function index in the two dry-eye groups and the control (p < 0.05). There were significant relationships between corneal sensitivity and the rose bengal and fluorescein scores in the three groups (p < 0.05). Hyposecretion of tears in dry eye may lead to pathologic changes in corneal epithelium and a decline in corneal sensitivity. Prompt treatment of dry eye is essential to maintain a normal corneal protective mechanism.

Cornea↗
PubMed1996

Improvement of corneal sensation and tear dynamics in diabetic patients by oral aldose reductase inhibitor, ONO-2235: a preliminary study.

The mechanism in the pathogenesis of diabetic corneal disease is unclear, but aldose reductase may be involved in the corneal disease. We studied the effects of an aldose reductase inhibitor (ARI) on the ocular surface of diabetic patients. Fourteen aphakic or pseudophakic patients with diabetes were treated with orally administered ONO-2235 (150 mg/day). Corneal sensation, vital staining of ocular surface, and tear production were examined before and 3 months after the administration. After a 3-month period of oral ARI, corneal sensation recovered significantly (from 4.1 +/- 4.8 to 3.0 +/- 3.1 g/mm2; p = 0.015), with parallel improvements in rose bengal and fluorescein staining scores (p < 0.05). Tear break-up time had also improved (p = 0.003). Results of Schirmer's test (p = 0.03) and the cotton-thread test (p = 0.0001) showed significant improvement in tear production. Improvement in the dynamics of tear production may be due to an improvement in corneal sensitivity. An oral ARI can improve corneal epithelial changes caused by diabetes, probably through recovery of corneal sensation and tear production.

Administration, Oral↗