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Biomedical subjects

K Higuchi

Publications and source records attributed to K Higuchi.

At least 361 records · Page 20Linked to original sources
PubMed1988

Sources of extracellular lysosomal enzymes released in organ-culture by developing and healing inflammatory lesions.

Developing and healing inflammatory lesions were topically produced in the skin of rabbits by sulfur mustard (SM). After the rabbits were sacrificed, the various lesions were removed and organ-cultured. The organ-culture fluids extracted the extracellular lysosomal enzymes (acid phosphatase, beta-glucuronidase, beta-galactosidase, and lysozyme), so that they could be measured biochemically along with lactic dehydrogenase (LDH), an enzyme marker for cell death. In tissue sections, the number and types of cells were counted, and their lysosomal enzyme content evaluated histochemically. The culture fluids from peak lesions contained much lower levels of all five enzymes than did culture fluids from healing lesions. When histological-histochemical-biochemical correlations were made, serum, macrophages (MN), and activated fibroblasts (but not tissue PMN) appeared to be major sources of extracellular lysosomal enzymes in peak lesions; and the dead PMN in the crusts and the activated fibroblasts in the tissues appeared to be major sources in healing lesions. The high lysosomal enzyme content of the crusts covering the lesions suggests that this passive barrier may also play an active role in promoting healing and in protecting against invasion by microorganisms.

Animals↗
PubMed1988

Proteases released in organ culture by acute dermal inflammatory lesions produced in vivo in rabbit skin by sulfur mustard: hydrolysis of synthetic peptide substrates for trypsin-like and chymotrypsin-like enzymes.

The purpose of these studies was to identify some of the extracellular proteolytic enzymes associated with the development and healing of acute inflammatory lesions. Lesions were produced in the skin of rabbits by the topical application of the military vesicant, sulfur mustard (SM). Full-thickness, 1-cm2 central biopsies of the lesions were organ-cultured for one to three days, and the culture fluids were assayed for proteases with a variety of substrates. When compared to culture fluids from normal skin, the culture fluids from both developing and healing SM lesions had three to six times the levels of proteases hydrolyzing two synthetic peptide substrates: (1) t-butyloxycarbonyl-Leu-Gly-Arg-4-trifluoromethylcoumarin-7-amide(Boc-Leu -Gly- Arg-AFC, herein abbreviated LGA-AFC), and (2) N-benzoyl-phenylalanine-beta-naphthyl ester (BPN). LGA-AFC is a substrate for trypsin, plasmin, plasminogen activator, thrombin, kallikrein, and the C3 and C5 convertases; BPN is a chymotrypsin and cathepsin G substrate. The culture fluids did not consistently hydrolyze four other synthetic peptide substrates or the proteins [14C]-casein and [14C]elastin. In order to determine the likely sources of LGA-AFCase and BPNase activity, we counted the number of granulocytes (PMNs), macrophages (MNs) and activated fibroblasts in histologic sections of developing and healing SM lesions, and we measured the levels of these enzymes in serum, in culture fluids of PMN and MN peritoneal exudate cells, and in culture fluids of two fibroblast cell lines. In SM lesions, serum and fibroblasts seemed to be the major source of LGA-AFCase, and serum alone the major source of BPNase. Tissue PMNs and MNs seemed to be only minor sources. The crusts of healing lesions, which were full of dead PMNs, seemed to be a rich source of both enzymes. In the SM lesion culture fluids, whether LGA-AFC and BPN were hydrolyzed by endopeptidases or only by exopeptidases could be determined by evaluating complex formation with alpha-macroglobulin proteinase inhibitors (alpha M). Endopeptidases, but not exopeptidases, are entrapped and inhibited by alpha M, because an internal peptide band in alpha M must first be hydrolyzed before molecular rearrangement (required for proteinase inhibition) occurs. The catalytic site of endopeptidases that are entrapped and inhibited by alpha M is known to remain active on (and reachable by) small synthetic peptide substrates such as LGA-AFC and BPN.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Lack of inhibitory effect of alpha-human atrial natriuretic polypeptide on cortisol secretion in cultured adrenocortical adenoma cells from the patients with Cushing's syndrome.

The effects of synthetic alpha-human atrial natriuretic polypeptide (alpha-hANP) on cortisol secretion by adrenocortical adenoma cells from patients with Cushing's syndrome (CS cells) in primary monolayer cultures, compared to cultured normal adrenal cells, were studied. alpha-hANP significantly inhibited cortisol secretion by human normal adrenal cells in culture, but had no direct effect on cortisol secretion from CS cells, in the presence or absence of 10(-8) M ACTH. alpha-hANP enhanced the accumulation of intracellular cyclic GMP in normal adrenal cells in culture, but not in CS cells. Visualization of [125I] iodo-alpha-hANP-specific binding sites by an in vitro receptor autoradiographic technique showed that these sites were lacking in adrenocortical adenoma tissues. These results suggest that the loss of alpha-hANP inhibitory effect on cortisol secretion in CS cells may be due to the absence of alpha-hANP receptor sites.

Adenoma↗
PubMed1988

Human apolipoprotein B (apoB) mRNA: identification of two distinct apoB mRNAs, an mRNA with the apoB-100 sequence and an apoB mRNA containing a premature in-frame translational stop codon, in both liver and intestine.

Human apolipoprotein B (apoB) is present in plasma as two separate isoproteins, designated apoB-100 (512 kDa) and apoB-48 (250 kDa). ApoB is encoded by a single gene on chromosome 2, and a single nuclear mRNA is edited and processed into two separate apoB mRNAs. A 14.1-kilobase apoB mRNA codes for apoB-100, and the second mRNA, which codes for apoB-48, contains a premature stop codon generated by a single base substitution of cytosine to uracil at nucleotide 6538, which converts the translated CAA codon coding for the amino acid glutamine at residue 2153 in apoB-100 to a premature in-frame stop codon (UAA). Two 30-base synthetic oligonucleotides (nucleotides 6523-6552 of apoB mRNA), designated apoB-Stop and apoB-Gln, were synthesized containing the complementary sequence to the stop codon (UAA) and glutamine codon (CAA), respectively. Analysis of intestinal apoB mRNA by hybridization with apoB-Stop and apoB-Gln probes and sequence analysis of apoB clones in two independent human small intestinal cDNA libraries established that intestinal apoB mRNA contained both the apoB mRNA that codes for apoB-100 and the apoB mRNA containing the premature in-frame stop codon, which codes for apoB-48. Investigation of hepatic apoB mRNA and two hepatic cDNA libraries by hybridization with the apoB-Stop and apoB-Gln synthetic probes as well as by cDNA sequencing revealed that liver apoB mRNA also contains both the apoB-100 mRNA and the apoB-48 mRNA containing the stop codon. The combined results from these studies establish that both human intestine and liver contain the two distinct apoB mRNAs, an mRNA that codes for apoB-100 and an apoB mRNA that contains the premature stop codon, which codes for apoB-48. The premature in-frame stop codon is not tissue specific and is present in both human liver and intestine.

Apolipoprotein B-100↗
PubMed1988

Homozygous hypobetalipoproteinemia: a disease distinct from abetalipoproproteinemia at the molecular level.

apoB DNA, RNA, and protein from two patients with homozygous hypobetalipoproteinemia (HBL) were evaluated and compared with normal individuals. Southern blot analysis with 10 different cDNA probes revealed a normal gene without major insertions, deletions, or rearrangements. Northern and slot blot analyses of total liver mRNA from HBL patients documented a normal size apoB mRNA that was present in greatly reduced quantities. ApoB protein was detected within HBL hepatocytes utilizing immunohistochemical techniques; however, it was markedly reduced in quantity when compared with control samples. No apoB was detectable in the plasma of HBL individuals with an ELISA assay. These data are most consistent with a mutation in the coding portion of the apoB gene in HBL patients, leading to an abnormal apoB protein and apoB mRNA instability. These results are distinct from those previously noted in abetalipoproteinemia, which was characterized by an elevated level of hepatic apoB mRNA and accumulation of intracellular hepatic apoB protein.

Apolipoproteins B↗
PubMed1988

Donor splice site mutation in the apolipoprotein (Apo) C-II gene (Apo C-IIHamburg) of a patient with Apo C-II deficiency.

The DNA, RNA, and protein of apo C-II have been analyzed in a patient with apo C-II deficiency (apo C-IIHamburg). Markedly reduced levels of plasma and intrahepatic C-II apolipoprotein were demonstrated by immunoblotting and immunohistochemical analysis. Northern, slot blot, and in situ hybridization studies revealed low levels of a normal-sized apo C-II mRNA. No major rearrangement of the apo C-II gene was detected by Southern blotting. Sequence analysis of apo C-II genomic clones revealed a G-to-C substitution within the donor splice site of intron II. This base substitution resulted in the formation of a new Dde I and loss of a Hph I restriction enzyme cleavage site. Amplification of the mutant sequence by the polymerase chain reaction and digestion with Dde I and Hph I restriction enzymes established that the patient was homozygous for the G-to-C mutation. This is the initial report of the DNA sequence of an abnormal apo C-II gene from a patient with deficiency of apo C-II. We propose that this donor splice site mutation is the primary genetic defect that leads to defective splicing and ultimately to an apo C-II deficiency in this kindred.

Adult↗
PubMed1988

[Correlation between breast development and hormone profiles in puberal girls].

In order to examine the relation between breast development and hormone levels, serum levels of hormones including LH, FSH, PRL, progesterone, 17 alpha OH-progesterone, estradiol (E2), pregnenolone, pregnenolone-sulfate, 17 alpha OH-pregnenolone, cortisol, dehydroepiandrosterone (DHA), dehydroepiandrosterone-sulfate (DHA-S), testosterone and delta 4-androstenedione were measured by RIA in 162 puberal girls aged 9 to 17 years. Height and body weight were also measured. Stages of breast development were classified into B1 to B5 according to Tanner et al. Results were as follow; 1) Both body weight and height increased as the breast stage advanced during puberty. 2) The correlation with the concentration of hormone such as LH, FSH, E2, DHA, DHA-S and T, and breast development was noticed during the puberal stage before the onset of menarche. A significant positive correlation was observed between DHA-S, body weight and each stage of breast development before and after the onset of menarche. From the results obtained above, the intimate relationship between breast development and steroid concentrations especially the adrenal steroid DHA-S was suggested.

Adolescent↗
PubMed1988

Metabolism of senile amyloid precursor and amyloidogenesis. Age-related acceleration of apolipoprotein A-II clearance in the senescence accelerated mouse.

Serum clearance kinetics of murine senile amyloid-related high-density lipoprotein (HDL) apoprotein A-II (apo A-II) was examined in the senescence-accelerated mouse, prone (SAM-P/1) and resistant (SAM-R/1), with 125I-HDL purified from both strains. In SAM-R/1, with 125I-HDL purified from both strains. In SAM-R/1, the serum half-life of apo A-II was not altered with increasing age and was practically identical to that of apo A-I. In 2-month old SAM-P/1, the serum half-life of both apo A-I and apo A-II was generally the same as observed in SAM-R/1. However, at age 6 and 12 months, in SAM-P/1, the serum half-life of apo A-II decreased significantly and was less than that of apo A-I. These age-related changes in apo A-II clearance kinetics were observed regardless of the HDL donor. The authors also examined the tissue distribution of injected apo A-II, using 125I-apo A-II reconstituted HDL, and found that several organs trapped more 125I radioactivity in old SAM-P/1 than in young mice. This evidence strongly suggests that age-related changes in the metabolic environment of apo A-II might affect senile amyloidogenesis in SAM-P/1.

Aging↗
PubMed1988

[Intra-arterial cis-platinum in the treatment of squamous cell carcinoma of the cervix].

Three patients with advanced cervical carcinoma were treated with two courses of cis-platinum (CDDP) intra-arterial administration. Histology of all patients revealed squamous cell carcinoma, keratinizing type, and all patients had stage IIIb diseases. CDDP at a dose of 50 mg was infused through each catheter of which tips were fixed in the bilateral internal iliac arteries via the opposite femoral arteries. The course of therapy was repeated at an interval of three to four weeks, so the total dose of CDDP in each patient was 200 mg. The bleeding from lesions, which occurred intermittently before therapy in all patients, was reduced after the primary course of therapy and completely stopped after the second one. Marked reduction of lesion on computed tomograph (CT) was confirmed in all patients. The reduction in the product of perpendicular diameters of measurable lesions on CT ranged from 40 to 50%. Adverse effects such as nephrotoxicity, myelosuppression and gastrointestinal toxicity were mild as compared with patients receiving intravenous administration of CDDP. The excellent clinical effects and tolerance observed in this study indicated that an intra-arterial administration of CDDP has a highly therapeutic efficacy in the treatment of squamous cell carcinoma of the cervix.

Carcinoma, Squamous Cell↗
PubMed1987

Identification of a novel in-frame translational stop codon in human intestine apoB mRNA.

Human apolipoprotein (apo) B exists in plasma as two isoproteins designated apoB-100 and apoB-48. ApoB-100 (512 kDa) and apoB-48 (250 kDa) are synthesized by the liver and intestine respectively. Analysis of apoB cDNA clones isolated from a human intestinal cDNA library revealed that the intestinal apoB mRNA contains a new in-frame translational stop codon. This premature stop codon is generated by a single base substitution of a 'C' to 'T' at nucleotide 6538 which converts the codon 'CAA' coding for the amino acid glutamine residue 2153 to an in-frame stop codon 'TAA'. The generation of a stop codon in the intestinal apoB mRNA appears to be tissue specific since it has not been reported in cDNA clones isolated from human liver cDNA libraries which code for the 4536 amino acid apoB-100. A potential polyadenylation signal sequence 'AATAAA' was also identified 390 bases downstream from the new stop codon. The new stop codon in the human intestinal apoB mRNA provides a potential mechanism for the biosynthesis of intestinal apoB-48.

Amino Acid Sequence↗
PubMed1987

The human apoB-100 gene: apoB-100 is encoded by a single copy gene in the human genome.

Northern blot analysis of human liver and intestine mRNA revealed two separate apoB mRNA of 14.1 and 7.5 kb in the intestine, and a single 14.1 kb apoB mRNA in the liver. cDNA probes which encode for the 5', middle, and 3' regions of the human apoB-100 mRNA have been utilized to evaluate the number of apoB genes present in the human genome by Southern blot hybridization analysis. Comparison of restriction enzyme digestions of high molecular weight leukocyte DNA and a known apoB genomic clone with cDNA probes for the 5', middle and 3' regions of the apoB-100 mRNA were consistent with only a single apoB gene per human haploid genome. Further analysis with synthetic oligonucleotides definitively established that there is a single apoB-100 gene. The two mRNA species observed in the intestine must be derived from a single nuclear apoB RNA transcript.

Apolipoprotein B-100↗
PubMed1987

A new blood pressure measuring apparatus equipped with a microcomputer system for conscious rats.

In order to measure the systolic blood pressure of conscious rats without thermal stress, a highly sensitive pulse sensor was developed using a light-emitting diode-photo diode system. The combination of this pulse sensor and microcomputer system led to the development of a six-channel automatic blood pressure measuring apparatus for rats. It can measure the systolic tail arterial pressure of conscious rats at 28-30 degrees C. The relationship between direct carotid arterial pressure (Y) and indirect tail arterial pressure (X) in conscious spontaneously hypertensive rats can be expressed as follows: Y = 0.95X + 19.9 (mm Hg, r = 0.988, 28 degrees C). The new apparatus was also used to confirm the acute hypotensive effects of hydralazine, nifedipine, and pindolol in spontaneously hypertensive rats and the subacute antihypertensive effect of trichlormethiazide in desoxycorticosterone/saline hypertensive rats.

Animals↗
PubMed1987

Study on the hyperresponsiveness of pituitary FSH to GnRH 6 weeks after delivery.

We investigated the mechanism underlying the hyperresponsiveness of pituitary FSH to GnRH stimulation in puerperal women 6 weeks after delivery. No pulse of LH during the 3-hour sampling period was observed in all of 4 puerperal women studied on day 42 postpartum, while each of 5 eumenorrheic women on day 8 or 9 of the normal cycle had one or two pulses of LH in the 3-hour sampling period. In puerperal women on day 42 postpartum, the mean basal level of serum FSH was slightly, but not significantly higher than that in eumenorrheic women on day 8 or 9 of the normal cycle, but the mean basal levels of serum LH and estradiol were significantly lower than those in eumenorrheic women. The response of serum FSH to GnRH stimulation was significantly and 2-fold higher in puerperal women on day 42 postpartum than in eumenorrheic women on day 8 or 9 of the normal cycle, but there was no difference in the response of serum LH to GnRH between the two groups. These results suggest that the hyperresponsiveness of pituitary FSH to GnRH stimulation in puerperal women on day 42 postpartum may result from the slower frequency of GnRH secretion.

Estradiol↗