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Biomedical subjects

K Iga

Publications and source records attributed to K Iga.

At least 19 recordsLinked to original sources
PubMed2005

Analysis of recessive lethality on swine chromosome 6 in a Göttingen miniature resource family.

Previously, we reported recessive gene(s) that terminate fetal development on swine chromosome (SSC) 6 between SW855 and SW122. The affected alleles originated from a Göttingen miniature pig used for construction of a Göttingen miniature pig x Meishan resource population. However, it is not known when the gene(s) are activated during fetal development, which is one of the important factors in selecting candidate genes responsible for fetal death. In the present study, a second swine population consisting of 159 progeny was produced by mating pigs carrying the deleterious allele(s). This population allowed us to narrow the genetic region harbouring the affected gene(s) and to demonstrate that the region was confined between RYR1 and SW782 (5.7 cM on the National Institute of Animal Industry (NIAI) map and 100 cR on the INRA/University of Minnesota porcine radiation hybrid panel map). In order to determine when the affected gene(s) are activated and in turn terminate fetal development, embryos produced in the second population were collected at several development stages and genotyped for markers in the region. Genes in the homozygous state affected embryo development between 9 and 11 days post-coitus.

Animals↗
PubMed2002

In vitro maturation and glutathione synthesis of porcine oocytes in the presence or absence of cysteamine under different oxygen tensions: role of cumulus cells.

The present study was conducted to evaluate the effect of cumulus cells on the in vitro maturation (IVM) and glutathione (GSH) synthesis of porcine oocytes cultured in the presence or absence of cysteamine under different oxygen tensions, and on their subsequent male pronucleus formation after in vitro fertilization (IVF). Cumulus-oocyte complexes (COCs) and cumulus-denuded oocytes (DOs) were cultured for 45 h in modified TCM-199 supplemented with or without 150 microM cysteamine under a humidified atmosphere of 5% CO2 in air (20% O2) or 5% CO2, 5% O2 and 90% N2. When cultured in medium supplemented with cysteamine under 20% O2 tension, the rates of COC maturation to the metaphase II (MII) stage were significantly higher than those of DOs (P<0.05). Regardless of the addition of cysteamine and oxygen tension, the rates of male pronucleus formation in COCs after IVM and IVF were significantly higher than in DOs (P<0.05). The GSH content of oocytes was significantly increased by the addition of cysteamine to the maturation medium (P<0.05), with significantly higher GSH content in COCs than in DOs (P<0.05). However, the GSH content of COCs and DOs was not significantly different when cultured in medium without cysteamine. These results indicate that cumulus cells play an important role in nuclear maturation to MII, GSH synthesis in porcine oocytes cultured in the presence of cysteamine, and subsequent male pronucleus formation after IVF.

Animals↗
PubMed2001

Iontophoretic pulsatile transdermal delivery of human parathyroid hormone (1-34).

Iontophoretic pulsatile transdermal delivery of hPTH(1-34) was examined in Sprague-Dawley (SD) rats, hairless rats and beagle dogs. Application for 60 min (200 microg; 0.1 mA cm(-2)) showed current-responsive increases in serum hPTH(1-34) levels in all the animals. In SD rats, the area under the curves of serum hPTH(1-34) levels (AUCs) were proportional to the doses (40, 120, 200, 400 and 1000 microg) and current densities (0.05, 0.1 and 0.15mA cm(-2)) applied. The absorption rates per 200-microg dose, calculated by a deconvolution method, were 6.7, 2.4 and 3.7 microg h(-1) for SD rats, hairless rats and beagle dogs, respectively. These values correlated well with the ratios of the skin porosity to the dermal thickness reported for these animals, which are believed to represent the reciprocal of the electrical resistance of the aqueous channels formed by the hair follicles. From this correlation, we suggested that absorption of hPTH(1-34) occurs mainly via the hair-follicle route, and that the absorption rate in man might be intermediate between those in hairless rats and beagle dogs. Three-fold repetitions of 30 min current with various rest intervals produced current-responsive triple pulses in serum hPTH(1-34) levels in SD rats. Seven-fold repetitions of current also produced similar current-responsive pulsatile serum hPTH(1-34) levels. However, peak serum hPTH(1-34) levels tended to decrease gradually after the fourth current application, possibly due to consumption of the electrodes, suggesting that three-fold repetitions of current might be optimal. These findings suggest that this iontophoretic administration system could create a repeated-pulsatile pattern of serum hPTH(1-34) levels without the necessity for frequent injections, and may be useful for the treatment of osteoporosis with hPTH(1-34).

Absorption↗
PubMed2001

Primary cardiac angiosarcoma detected by magnetic resonance imaging but not by computed tomography.

A 51-year-old man with a primary angiosarcoma of the right atrium is reported. The angiosarcoma was not detected by transthoracic echocardiography or computed tomography, but magnetic resonance imaging and transesophageal echocardiography did show the tumor of the right atrial free wall. We performed a transvenous endomyocardial biopsy of the tumor under the guidance of transesophageal echocardiography and made the pathological diagnosis. This case demonstrates the advantage of magnetic resonance imaging and transesophageal echocardiography for tumor detection over transthoracic echocardiography and computed tomography and the usefulness of transesophageal echocardiography for guiding the right atrial endomyocardial biopsy procedure.

Biopsy↗
PubMed2001

Relationship between papillary muscle size and benefit to cardiac function in mitral valve replacement with chordal preservation.

BACKGROUND AND AIM OF THE STUDY: Mitral valve replacement (MVR) with chordal preservation in patients with chronic mitral regurgitation (MR) has been reported to maintain systolic function of the left ventricle. However, the benefits of MVR with chordal preservation are not always predictable. The study aim was to ascertain the influence that papillary muscle (PM) size has on cardiac function after MVR with chordal preservation. METHODS: Postoperative regional shortening and its relationship with PM size were investigated by two-dimensional echocardiography in 18 patients who underwent MVR with chordal preservation, and nine patients without chordal preservation between 1986 and 1998 at Tenri Hospital. The PM cross-sectional area was measured in each patient, as well as postoperative fractional shortening (FS) of the septolateral, anteroposterior and vertical dimensions of the left ventricle. The technique of preserving all chordae tendineae involved reattaching the anterior leaflet chordae to the mitral annulus near each commissure. RESULTS: Postoperative FS of the septolateral and anteroposterior dimensions was better in patients with chordal preservation than in those without. In the former subgroup, a larger PM was associated with better FS of the left ventricle in the septolateral dimension (anterior PM, p <0.001, r = 0.78; posterior PM, p = 0.0010, r = 0.69), but not in the anteroposterior or vertical dimensions. This discrepancy in the relationship between PM size and functional benefits among the three dimensions may be related to the direction in which the PMs are suspended in our technique, or its effect on regional left ventricular function. CONCLUSION: The present study indicated that PM size may be used as a factor to better predict the outcome of MVR with chordal preservation.

Adult↗
PubMed2000

Novel sustained-release dosage forms of proteins using polyglycerol esters of fatty acids.

In order to develop a novel delivery system for proteins based on polyglycerol esters of fatty acids (PGEFs), we studied a model system using interferon-alpha (IFN-alpha) as the test protein. A cylindrical matrix was prepared by a heat extrusion technique using a lyophilized powder of the protein and 11 different types of synthetic PGEFs, which varied in degree of glycerol polymerization (di- and tetra-), chain length of fatty acids (myristate, palmitate and stearate) and degree of fatty acid esterification (mono-, di- and tri-). In an in-vitro release study using an enzyme-linked immunosorbent assay (ELISA) as a detection method, the matrices prepared from a monoglyceride (used for comparison) and from diglycerol esters exhibited a biphasic release pattern with a large initial burst followed by slow release. In contrast, the matrices prepared from tetraglycerol esters showed a steady rate of release without a large initial burst. In an in vivo release study, initial bursts of IFN-alpha release were, also, dramatically reduced when the matrices were prepared from the tetraglycerol esters of palmitate and stearate, and the mean residence time (MRT) of IFN-alpha was prolonged, whereas the matrices prepared from monoglyceride and from diglycerol esters showed large initial bursts of IFN-alpha release. Since the release rates from the matrices prepared from the tetraglycerol esters of palmitate and stearate were governed by Jander's equation modified for a cylindrical matrix, the release from those matrices was concluded to be a diffusion-controlled process. The bioavailability of IFN-alpha after implantation of the matrix formulation prepared using all types of PGEFs, except for tetraglycerol triesters, was almost equivalent to that after injection of IFN-alpha solution; consequently, IFN-alpha in these matrices appears to remain stable during the release period.

Animals↗
PubMed2000

Tumor necrosis factor-alpha and its receptor in the corpus luteum of pregnant cows.

The objective of this study was to investigate the presence of tumor necrosis factor (TNF)-alpha mRNA and TNF-alpha receptors in the bovine corpus luteum (CL) during the gestation period. TNF-alpha mRNA and TNF-alpha receptors were determined on bovine CL from pregnant cows at three stages: trimester I (fetal crown-rump length; 6-20 cm), trimester II (25-45 cm) and trimester III (50-80 cm). TNF-alpha mRNA was detected by an RT-PCR analysis in the CL of all stages of gestation. A Scatchard analysis revealed the presence of a high-affinity binding site (Kd; 5.1-6.9 nM) in the CL membranes collected at each stage of gestation. Furthermore, the concentrations of TNF-alpha receptors in the CL of trimesters I (24. 0 +/- 1.95 pmol/mg protein) and III (21.6 +/- 2.39 pmol/mg protein) of gestation were significantly higher than the concentration in trimester II (14.9 +/- 2.07 pmol/mg protein) (P < 0.05). These results indicate that TNF-alpha is locally produced and that TNF-alpha receptors are present in bovine CL during the gestation period, and suggest that TNF-alpha plays one or more roles as a paracrine factor in regulating bovine CL function during the entire gestation period.

Animals↗
PubMed2000

Pharmacologic effect of recombinant human IFN-alpha, continuously released from a matrix prepared from a polyglycerol ester of fatty acids, on 2',5'-oligoadenylate synthetase activity in murine liver.

The objective of this study was to assess the pharmacologic effect of continuously released recombinant human interferon-alpha (rHuIFN-alpha) in the liver, the target organ of chronic hepatitis B and C, using 2',5'-oligoadenylate synthetase (2',5'-OAS) activity as an indicator of an antiviral state. A cylindrical matrix prepared from tetraglycerol dipalmitate (TGDP), a polyglycerol ester of fatty acids (PGEF), released rHuIFN-alpha in a pseudo-zero-order manner for about 1 week after implantation into mice, without any major loss of rHuIFN-alpha biologic activity during the release period. To evaluate the pharmacologic effect of the rHuIFN-alpha continuously released from this type of matrix, we established a murine test system. Bolus injections of rHuIFN-alpha solution at three doses increased 2',5'-OAS activities in murine liver extract and serum in a dose-dependent manner, indicating that this system is suitable for evaluating rHuIFN-alpha activity. After subcutaneous insertion of TGDP-matrix implants containing 5.5x10(7) IU rHuIFN-alpha per animal, 2',5'-OAS activities in both liver extracts and serum increased rapidly and remained high for over 1 week. Subcutaneous injections of an equivalent total dose (5.0x10(7) IU/animal per week) of rHuIFN-alpha solution in three or seven fractions prolonged 2',5'-OAS activities compared with a single bolus injection. Comparing 2',5'-OAS activity on day 7 and the portion of the area under the 2',5'-OAS activity-time curve above the normal level (deltaAUC) between the TGDP-matrix implant and multiple injections of the solution revealed that continuously released rHuIFN-alpha has an effect almost equivalent to that of three or seven injections of the solution per week.

2',5'-Oligoadenylate Synthetase↗
PubMed2000

Carotid brainstem reflex myoclonus after hypoxic brain damage.

A patient comatose after acute anoxia developed bilaterally synchronous, periodic myoclonic jerks most prominently in the bilateral upper limbs. Although the myoclonus seemed to occur spontaneously, electrophysiological studies showed that the myoclonic jerks correlated in timing and size with arterial pulses, and was suppressed by massage over the carotid sinus. It is proposed that the present myoclonus is a variant of brainstem reflex myoclonus in which arterial pulses served as intrinsic trigger stimuli via the carotid sinus and the medullary reticular formation.

Aged↗
PubMed2000

Clinical characteristics of patients with fresh left ventricular thrombus.

The present study analyzed the clinical backgrounds of 9 patients with fresh left ventricular thrombus (LVT) detected by two-dimensional echocardiography during the past 5 years. Patients with acute myocardial infarction were excluded. Left ventricular systolic function was disturbed either diffusely or segmentally in all patients with a mean ejection fraction of 33%. In 7 patients, echocardiography was performed shortly after furosemide therapy for New York Heart Association class IV congestive heart failure; echocardiography was also performed just before treatment in 4 of the 7 patients and LVT was not detected in any of them. Two patients died of underlying disorders within 2 months of detection of the thrombus. However, the LVT disappeared in the other 7 patients without any thromboembolic episodes during the 6 months after starting anticoagulant therapy. As fresh LVT developed shortly after diuretic therapy in patients with severe congestive heart failure associated with left ventricular systolic dysfunction, concomitant anticoagulant therapy is recommended.

Aged↗
PubMed2000

Color flow signal in the left atrium as a mirror image artifact suggesting one leaflet constriction of the St. Jude Medical valve: a case report.

Color Doppler echocardiography detected an abnormal color flow signal originating from the prosthetic mitral valve and extending to the left atrium during diastole in an 84-year-old woman with St. Jude Medical valve replacement. The flow was away from the transducer and almost identical to the left ventricular inflow signal except for the direction. Cinefluoroscopy showed one of the leaflets fixed at systole whereas the other leaflet was mobile. After reinforcement of anticoagulant therapy, this abnormal color flow signal disappeared and motion of both leaflets normalized. This color flow signal, presumably a mirror image artifact of the left ventricular inflow caused by the immobilized leaflet, could be a sign of one leaflet constriction in patients with St. Jude Medical valve replacement.

Aged↗
PubMed2000

[Coronary flow after successful angioplasty in patients with acute myocardial infarction: comparison between coronary flow reserve by nicorandil and papaverine].

In order to evaluate coronary flow response to 2 different vasodilators, nicorandil and papaverine, in patients with myocardial infarction, we measured coronary flow reserve using a Doppler guide wire in infarct-related and non infarct-related arteries. The study group consisted of 28 patients with first acute myocardial infarction 3 weeks after successful coronary angioplasty within 6 hr after symptom onset. Twelve patients with atypical chest pain served as the control group. Coronary flow reserve induced by intracoronary papaverine(12 mg) was lower in infarct-related arteries than in non infarct-related arteries, but there were no differences in coronary flow reserve induced by intracoronary nicorandil(1 mg) between infarct-related and non infarct-related arteries. Coronary flow reserve induced by nicorandil was lower than that by papaverine in non infarct-related arteries and the control group. However, there were no differences between coronary flow reserve induced by nicorandil and papaverine in infarct-related arteries. Vasodilatory response induced by nicorandil was relatively preserved in infarct-related arteries compared with papaverine. These results suggest that impairment of coronary microvascular response in infarct myocardium varies in the different sites acted on by different vasodilator agents.

Angioplasty, Balloon, Coronary↗
PubMed1999

Intermittently audible the "third heart sound" as a sign of complete atrio-ventricular block in patients with a VVI pacemaker.

BACKGROUND: It is not known that an S3 can be audible intermittently. We have recognized this in patients with VVI pacing in whom sinus rhythm has been preserved. SUBJECTS AND METHODS: Subjects consisted of consecutive 39 patients with VVI pacemaker implantation and preservation of sinus rhythm. We tried to find out what percentage of these patients have an intermittent S3 and also to elucidate the mechanism of this sound by Doppler echocardiography. The PP interval and RR intervals were measured and ¿PP-RR¿/RR was calculated. One doctor carried out auscultation from the left sternal border to the apex for 5-6 consecutive beats while the patients held their breath. Transmitral flow velocity was measured by pulsed Doppler echocardiography with a paper speed of 100 cm/sec. A wave velocity was measured when a P wave coincided with late diastole. E wave velocity was measured when no A wave was present in early diastole. The maximal summation of E and A waves (E+A) velocity was measured. RESULT: An intermittent S3, being audible in 21 patients (group A) and not audible in 18 patients (group B), coincided with maximal E+A velocity. There was no statistical age difference between the two groups. Both maximal E+A velocity, and A velocity were higher in group A than group B (116.2 cm/sec Vs 90.8 cm/sec P<0.0001, 80.6 cm/sec Vs 56.4 cm/sec P<0.0001 respectively), while E velocity was not statistically different (68.3 cm/sec Vs 60.3 cm/sec). In 5 of 9 cases in whom an intermittent S3 was not audible regardless of more than 100 cm/sec of E+A velocity, the calculated ¿PP-RR¿/RR was less than 0.1. CONCLUSION: An intermittently audible S3 is one of the physical signs of complete atrio-ventricular block. It occurs when a strong atrial contraction develops exactly at the time of rapid left ventricular filling. However, when the PP and RR intervals are too close, the S3 may be difficult to discern.

Adult↗
PubMed1999

Influence of gravity on pulmonary venous flow velocity patterns: analysis of left and right pulmonary venous flow velocities in left and right decubitus positions.

BACKGROUND: The pulmonary venous flow signal measured by transesophageal echocardiography is generally recorded from the left upper pulmonary vein in the left lateral decubitus position, whereas that by transthoracic echocardiography is from the right upper pulmonary vein in the left semi-lateral decubitus position. The purpose of this study was to evaluate the influence of the postural change on the peak flow velocities of the left and right pulmonary veins and whether the parameters of the left and right pulmonary venous flow can be used interchangeably. METHODS AND RESULTS: The study group consisted of 37 patients with normal left ventricular filling pressure and in whom the systolic forward flow signals from both pulmonary veins recorded in the left and right lateral decubitus positions were clear enough to differentiate as biphasic. The peak early systolic (peak S1) and diastolic velocities were significantly increased when the pulmonary vein was on the recumbent subject's upper side, whereas the peak late systolic velocity (peak S2) was significantly increased when the pulmonary vein was on the recumbent subject's lower side. The peak S1 was higher than the peak S2 when the pulmonary vein was on the recumbent subject's upper side, whereas the reverse relation was seen when the pulmonary vein was on the recumbent subject's lower side. CONCLUSIONS: We should take into consideration the body position and the side on which the pulmonary vein is situated in evaluating the peak flow velocities of the pulmonary veins.

Adult↗