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Biomedical subjects

K Miki

Publications and source records attributed to K Miki.

At least 325 records · Page 18Linked to original sources
PubMed1989

Genomic divergence of HIV-2 from Ghana.

Genetic variability in human immunodeficiency virus type 1 (HIV-1) has been studied extensively, but the total nucleotide sequence of the HIV-2 genome has been reported only in two strains. For phylogenetic analyses of HIV, the genetic variability of HIV-2 should be investigated. This paper reports the complete nucleotide sequence of an HIV-2 isolate from Ghana, HIV-2[GH-1]. This virus showed approximately 85% homology in overall nucleotide sequence with HIV-2ROD. The amino acid sequence of the gag and pol proteins of HIV-2[GH-1] showed 90% homology with those of HIV-2ROD, but its env gene and central regions were highly variable (more than 20% divergence in amino acids), indicating the presence of extensive genetic heterogeneity in HIV-2. However, the sequences with specific functions were relatively well conserved in these HIV-2 isolates.

Amino Acid Sequence↗
PubMed1989

Difference of activation processes and structure of activation peptides in human pepsinogens A and progastricsin.

The activation processes of two human pepsinogens A (pepsinogens 3 and 5) and progastricsin were compared with special attention to pepsinogens 3 and 5. Each zymogen was converted to pepsin in a stepwise manner through intermediate forms. In pepsinogens A, the major cleavage site was the Leu23-Lys24 bond and this cleavage was suggested to occur intramolecularly. When each of the pepsins A was added to the corresponding pepsinogen A exogenously, the latter was rapidly converted to pepsin, releasing the 47-residue intact activation segment. In this case, the Leu47-Val48 bond connecting the activation segment with the pepsin moiety was cleaved by an intermolecular reaction. On the other hand, when the pepsinogen A-pepstatin complex was attacked by each corresponding pepsin A added exogenously, significant cleavage by an intermolecular reaction occurred at the Asp25-Phe26 bond, generating the Phe26-intermediate form. These shifts of the cleavage sites in pepsinogens A depending on the activation conditions are likely to correlate with the conformation of the activation segment. These results can be explained consistently in terms of a proposed molecular model of activation.

Amino Acid Sequence↗
PubMed1989

The significance of low serum pepsinogen levels to detect stomach cancer associated with extensive chronic gastritis in Japanese subjects.

Serum pepsinogen levels were measured in 137 stomach cancer patients and compared with those of 288 normal cancer-free subjects. The serum pepsinogen levels of stomach cancer patients, especially pepsinogen I and the pepsinogen I/pepsinogen II ratio were significantly lower than those of normal controls and correlated well with the extent of chronic gastritis associated with the cancerous stomach. These results were in good accordance with the results of previous studies indicating that the cancer derived from the stomach where chronic gastritis/intestinal metaplasia is extensive. The high sensitivity and specificity of this non-invasive serum test to detect chronic gastritis suggested the possibility of its application to the mass screening of stomach cancer.

Adenocarcinoma↗
PubMed1989

In situ localization of pepsinogens I and II mRNA in human gastric mucosa.

Localization of pepsinogens I and II mRNA in the human gastric mucosa was investigated by an in situ hybridization method using digoxigenin-labeled cDNA probes. Gastric fundic mucosa from healthy volunteers, which was stained with digoxigenin-labeled pepsinogens I and II cDNA probes, showed positive staining in the cytoplasm of both chief cells and mucous neck cells. In contrast, gastric antral mucosa stained with the pepsinogen I cDNA probe showed no positive reaction in the surface mucous cells or pyloric glands. On the other hand, the pyloric glands were stained positively with the pepsinogen II cDNA probe and the staining appeared to be identical to that obtained with the antipepsinogens I and II monoclonal antibodies using the avidin-biotin-peroxidase complex technique. These results are consistent with those of previous studies that have employed immunochemical and immunohistochemical techniques.

DNA↗
PubMed1989

Prevention of neonatal HBV infection with the combination of HBIG and HBV vaccine and its long-term efficacy in infants born to HBeAg positive HBV carrier mothers.

Seventy-three infants born to HBeAg positive HBV carrier mothers were protected from neonatal HBV infection with our standard prevention schedule consisting of two doses of HBIG (0,2 mo) and three doses of HBV vaccine (2, 3, 5 mo). In 62 infants who successfully responded to HBV vaccine with a titer of anti-HBs greater than 2(3), anti-HBs titer was monitored for as long as 48 months (25.6 +/- 11.0 mo) and found to decrease as follows: 5.1 +/- 1.7 at 12 mo., 4.5 +/- 1.8 at 18 mo., 4.2 +/- 1.8 at 24 mo., 4.0 +/- 1.6 at 30 mo., 3.7 +/- 1.7 at 36 mo., 3.2 +/- 2.0 at 48 mo. During the follow-up period, eight HBV events (11.9%) were demonstrated: one case showed an increase of anti-HBs, three showed a reappearance of anti-HBc alone, three showed a reappearance of anti-HBc with increase of anti-HBs, and one became a chronic HBV carrier. All infants were further divided into three groups by their maximal response of anti-HBs to HBV vaccine: Group I (greater than or equal to 2(6)), Group II (2(3)-2(5)), and Group III (2(2) greater than or equal to). Group I sustained a higher titer from 12 to 30 months of age and had less HBV events than G-II and G-III. Our study suggests that acquisition of a high titer of anti-HBs is important in long-term prevention of HBV infection as well as in the neonatal period in infants born to HBeAg positive HBV carrier mothers.

Carrier State↗
PubMed1989

Transient infantile hyperthyrotrophinaemia.

Sixteen cases of transient infantile hyperthyrotrophinaemia were followed up for two to seven years. Concentrations of serum triiodothyronine, thyroxine, and free thyroxine were maintained within the normal range in all cases. All but one child, who had a hearing disturbance, showed normal mental development with normal physical and skeletal maturation. Eleven children had normal concentrations of serum thyroid stimulating hormone and no signs or symptoms of thyroid dysfunction; in three children, diffuse small goitres developed and two further children showed relapse with slightly raised concentrations of thyroid stimulating hormone. It is concluded that 'transient infantile hyperthyrotrophinaemia' is a syndrome, which differs from typical transient neonatal hypothyroidism, and that careful follow up is necessary because some children show signs of mild pituitary-thyroid dysfunction in later childhood.

Child Development↗
PubMed1989

Renal sympathetic nerve activity and natriuresis during water immersion in conscious dogs.

The role of renal sympathetic nerve activity (RSNA) in the natriuresis and diuresis induced by head-out water immersion (WI) was studied in eight conscious female dogs. The dog was instrumented chronically with a stainless steel electrode for the measurement of RSNA and two catheters for the measurements of systemic arterial (Pa) and central venous (Pv) pressures. The WI caused an immediate reduction of RSNA by 43 +/- 7% (P less than 0.05), and this low level was sustained throughout a 120-min WI under thermoneutral conditions (37 degrees C). Urine flow and sodium excretion increased by 211 +/- 54 (P less than 0.05) and 240 +/- 122% (P less than 0.05), respectively, but creatinine clearance did not change significantly during WI. A step increase in Pa (by 10 +/- 4 mmHg, P less than 0.05) and Pv (by 10.0 +/- 0.8 mmHg, P less than 0.05) was observed also during WI. In another series of studies, renal denervations were performed 2-4 wk before the experiment in six of the same dogs. Dogs with renal denervation showed no significant changes in urine flow and sodium excretion in response to WI, whereas Pa and Pv increased by 10 +/- 7 and 10.0 +/- 2.0 mmHg relative to the control level, respectively. It is concluded that the reduction of RSNA observed during WI plays a major role in the natriuresis in the dog.

Animals↗
PubMed1989

Renal sympathetic nerve activity and renal responses during head-up tilt in conscious dogs.

Renal sympathetic nerve activity (RSNA) was measured in conjunction with functional responses of the kidney during head-up tilt in eight conscious female dogs. A 40 degree head-up tilt resulted in a sustained increase in RSNA by 53 +/- 10% (P less than 0.05) relative to control level. Urine flow and osmolal and sodium excretions decreased significantly to a nadir of -55 +/- 4, -42 +/- 7, and -59 +/- 10%, respectively, whereas free water clearance and creatinine clearance did not change significantly during head-up tilt. The systemic arterial pressure (at kidney level) increased significantly from 110 +/- 4 to 129 +/- 6 mmHg, and central venous pressure decreased significantly from -0.7 +/- 0.5 to -7.6 +/- 0.6 mmHg. The chronic bilateral renal denervation, which was performed 2-4 wk before the experiment, abolished both the antidiuretic and antinatriuretic responses to heald-up tilt. These results indicate that an increase in RSNA plays a significant role in the decrease in urine flow and sodium excretion induced by 40 degree head-up tilt in conscious dogs.

Animals↗
PubMed1989

Interstitial and intravascular pressures in conscious dogs during head-out water immersion.

Water immersion (WI) causes an increase in plasma volume in humans and dogs. To determine the mechanism for this fluid movement, the transmission of external water hydrostatic pressure to the interstitial and vascular compartments was studied in six conscious dogs. Systemic arterial, central venous, peripheral arterial (ulnar artery) and venous (cephalic vein), pleural, intra-abdominal, and interstitial fluid hydrostatic (by Guyton's capsule and wick catheter method) pressures and external reference water pressure were measured at three different levels of WI: 1) extremities only, 2) midchest, and 3) midcervical levels at 37 degrees C. There was a significant linear relationship between interstitial fluid hydrostatic pressure (X) and external water pressure (Y): (Y = 0.86X + 1.4, r = 0.93 by Guyton's capsule; Y = 0.85X + 2.4, r = 0.93 by wick catheter. However, vascular pressures did not change when dogs were immersed at the level of the extremities. These pressures increased only during WI at the midchest and midcervical levels. Therefore the pressure gradient that develops between the interstitial and intravascular compartments is probably the major reason for the transcapillary fluid shift during WI.

Abdomen↗
PubMed1989

[Total replacement of the urinary bladder using an ileal pouch bladder].

We have used the continent ileal bladder as a bladder replacement after radical cystectomy. The ileal bladder is an ileal pouch which is anastomosed to the urethral stumps. The ureters are implanted by a free end ureteroileostomy. The long term results with 26 patients who underwent this procedure are reported. In the early postoperative period, urodynamic and radiographic studies revealed small capacity and high intravesical pressure of the ileal bladder. However, it became a low pressure reservoir with increased capacity gradually. The average bladder capacity was about 250 ml and average residual urine was 30 ml. Most of the patients were continent in the daytime if the voiding intervals were less than 3 hours at night, some patients were incontinent. Urinary leakage was the most frequent complication. VUR and hydronephrosis were still the problems to be solved. The ileal pouch bladder is a valuable procedure in properly selected cases.

Adult↗
PubMed1989

[Serum pepsinogen I level in patients with stomach cancer--its value and limitation in clinical use].

We measured serum pepsinogen I (PG I) levels in 137 stomach cancer patients by the previously described radioimmunoassay and compared them with those of normal cancer-free subjects by a gastric mass survey in a certain workplace. The value and limitations of the measurement of serum PG I level in the diagnosis of stomach cancer were analyzed statistically according to the histology and stage of the disease. The mean serum PG I level of stomach cancer patients was 21.3 micrograms/l [early stage (N = 53): 24.9 micrograms/l; advanced stage (N = 84): 19.2 micrograms/l; well-differentiated (N = 62): 19.5 micrograms/l poorly-differentiated (N = 75): 22.7 micrograms/l]. It was significantly lower than that of the age-matched cancer-free subjects. As to the stage and histology of the disease, early stage poorly-differentiated adenocarcinoma and the same stage well-differentiated adenocarcinoma took the mean serum PG I level of 30.6 micrograms/l (N = 26, p less than 0.05) and 20.2 micrograms/l (N = 27, p less than 0.001). In the advanced stage, they were 19.3 micrograms/l (N = 49, p less than 0.001) and 18.6 micrograms/l (N = 35, p less than 0.001), respectively. Using a cut off point of 25 micrograms/l to separate subjects with stomach cancer, sensitivity was 61% and specificity, 80%. These results suggest a possibility of serological screening of the subjects with stomach cancer and indicate that the measurement of serum PG I level will probably contribute much to the improvement of the effectiveness of a gastric mass survey.

Adenocarcinoma↗
PubMed1989

Changes in insulation of wetsuits during repetitive exposure to pressure.

This investigation was intended to a) establish a relationship between pressure and thickness (and hence insulation) of wetsuits during acute changes in pressure from 0.5 to 5 atmospheres absolute (ATA); b) determine the effect of repetitive compression-decompression (C-D) procedures on the insulation properties of wetsuits; and c) assess the possible recovery of insulation after cessation of repetitive C-D. Various wetsuits with different thicknesses and types of linings were selected. In all wetsuits, insulation and thickness were both reduced as similar, curvilinear functions of acutely increasing pressure in the range of 0.5-5.0 ATA. Effects of repetitive C-D (3 ATA) were studied in 5-mm-thick suit samples with various linings. The insulation of suits (0.100-0.120 degrees C.W-1.m-2) rapidly decreased after the first 5000 C-D. In suits without linings (skin suits), the insulation was reduced to 0.080 degrees C.W-1.m-2 at 5000 C-D and revealed no further reduction during the continuation of C-D cycles up to 30,000. Suits lined with single- or double-sided jersey showed a continuous decrease in the insulation and thickness as the number of cycles increased up to 12,000 and remained at a lowered value (0.060 degrees C.W-1.m-2) until the termination of C-D (30,000 times). A nearly complete recovery of thickness was seen 10 days after cessation of C-D treatment in the skin suit when C-D cycles were less than 3500; however, no recovery was observed in suits with linings (either single- or double-sided) in 25 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Atmospheric Pressure↗
PubMed1988

Cell-specific hypomethylation of the pepsinogen gene in pepsinogen-producing cells.

The pepsinogen gene is hypomethylated in the stomach, in which it is expressed. For demonstration that this hypomethylation of the pepsinogen gene in the stomach reflects pepsinogen-producing cells, we analyzed fractions of dispersed mucosal cells with various contents of pepsinogen-producing cells prepared from guinea pig stomach by centrifugal elutriation. mRNA expression and the extent of hypomethylation of the pepsinogen gene in each fraction was closely correlated with the content of pepsinogen-producing cells. These results suggested hypomethylation of the pepsinogen gene in pepsinogen-producing cells and differential pepsinogen gene methylation in cell subpopulations in the stomach.

Animals↗
PubMed1988

Enzyme-linked immunosorbent assays for serum pepsinogens I and II using monoclonal antibodies--with data on peptic ulcer and gastric cancer.

Serum pepsinogen I and pepsinogen II levels in 369 healthy controls, 38 duodenal ulcer, 30 gastric ulcer and 46 stomach cancer including 21 early and 25 advanced gastric cancer patients were measured by enzyme-linked immunosorbent assays using pepsin moiety-reacting monoclonal antibodies to pepsinogens I and II. Serum pepsinogen I and pepsinogen II levels were higher in the duodenal and gastric ulcer groups than in the control. Although there was no significant difference in serum pepsinogen II between stomach cancer and control, serum pepsinogen I was significantly lower in the former than in the latter and also in advanced gastric cancer than in early gastric cancer. A specific negative correlation of serum pepsinogen I with patient age was observed in stomach cancer but not in peptic ulcer or control groups. Receiver operating characteristic analysis was performed and indicated that serum pepsinogen I, compared with serum pepsinogen II or the pepsinogen I/pepsinogen II ratio, is the most effective marker for stomach cancer.

Antibodies, Monoclonal↗
PubMed1988

Sequence of simian immunodeficiency virus from African green monkey, a new member of the HIV/SIV group.

Some wild African green monkeys are known to be naturally infected with a retrovirus related to human immunodeficiency virus (HIV) without having any apparent symptoms of an AIDS-like disease. This simian immunodeficiency virus, designated SIVAGM, may be helpful in clarifying the evolution and pathogenicity of HIV. Some virus strains that were previously reported to be isolated from African green monkeys were shown to be laboratory contaminations of SIVMAC (SIV from a rhesus macaque) Here we report the complete DNA sequence of authentic SIVAGM, which was isolated from a naturally infected African green monkey of Kenyan origin. Comparison of the genome of SIVAGM with those of known HIV/SIVs indicates that the virus is a new simian lentivirus that is approximately equally distantly related to HIV-1 and HIV-2 in contrast to SIVMAC, which is much closer to HIV-2 than to HIV-1 (refs 5, 9).

Amino Acid Sequence↗