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Biomedical subjects

R Higuchi

Publications and source records attributed to R Higuchi.

At least 55 records · Page 3Linked to original sources
PubMed1996

Biotin deficiency in an infant fed with amino acid formula and hypoallergenic rice.

An amino acid formula produced in Japan is not supplemented with biotin since biotin is not permitted as a food additive. Biotin deficiency developed in an 11-month-old Japanese infant who had been diagnosed as a neonate with cow milk and soy bean allergy and fed with an amino acid formula and hypoallergenic rice processed by protease. Serum levels of zinc, essential fatty acids and biotinidase were within the normal range while that of biotin was below the normal range. Urinary 3-hydroxy-isovalerate and slightly elevated levels of plasma branched-chain amino acids disappeared 1 week after oral supplementation with 1 mg day-1 of biotin as did the symptoms of orificial skin lesions, lethargy, hypotonia and alopecia later. In summary, to prevent biotin deficiency, biotin should be added to the Japanese amino acid formula.

Biotin↗
PubMed1996

Multiple dermoid cysts on the forehead. Case report.

A 41-year-old man presented with multiple tumours on the forehead which had developed over a 20-year period. Preoperative computed tomography of the brain showed multiple subcutaneous lesions in the frontal region with no intracranial extension. Histological examination of a biopsy specimen from one of the tumours showed a dermoid cyst. The patient underwent excision of the tumours, and the resulting skin defect was covered with a full-thickness skin graft. His postoperative course was uneventful. Dermoid cysts of the head and neck are relatively rare, and usually occur in childhood as solitary lesions.

Adult↗
PubMed1994

Effective amplification of long targets from cloned inserts and human genomic DNA.

We have used the polymerase chain reaction (PCR) to amplify up to 22 kb of the beta-globin gene cluster from human genomic DNA and up to 42 kb from phaga lambda DNA. We have also amplified 91 human genomic inserts of 9-23 kb directly from recombinant lambda plaques. To do this, we increased pH, added glycerol and dimethyl sulfoxide, decreased denaturation times, increased extension times, and used a secondary thermostable DNA polymerase that possesses a 3'-to 5'-exonuclease, or "proofreading," activity. Our "long PCR" protocols maintain the specificity required for targets in genomic DNA by using lower levels of polymerase and temperature and salt conditions for specific primer annealing. The ability to amplify DNA sequences of 10-40 kb will bring the speed and simplicity of PCR to genomic mapping and sequencing and facilitate studies in molecular genetics.

Bacteriophage lambda↗
PubMed1994

Bioactive terpenoids from Octocorallia, I. Bioactive diterpenoids: litophynols A and B from the mucus of the soft coral Litophyton sp.

Two new eunicellin-type diterpenoids, litophynols A [1] and B [2], and the known diterpenoids litophynins E [3], H [11], and I monoacetate [12], were isolated from the mucus secreted by the soft coral Litophyton sp. Their structures have been elucidated on the basis of spectral and single crystal X-ray analyses. These compounds have hemolytic activity.

Animals↗
PubMed1993

Pearson's marrow/pancreas syndrome: a histological and genetic study.

A patient with features of Pearson's syndrome who presented with transfusion-dependent severe macrocytic anaemia, neutropenia, thrombocytopenia, and insulin-dependent diabetes mellitus in the neonatal period is described. His bone marrow was characterized by marked vacuolization of myeloid precursors and ringed sideroblasts. Autopsy examination revealed fibrosis and steatosis of the liver, reduction in the size and number of the islets, fibrosis and acinar atrophy of the pancreas, vacuolation of renal tubules, glomerulosclerosis, and "ragged red" fibres of skeletal muscles. Analysis of mitochondrial DNA (mtDNA) from the autopsied liver and skeletal muscle showed mtDNA heteroplasmy in both tissues, with one population of mtDNA deleted by 7374 bp. The deleted region was bridged by a single nucleotide, C, in normal mtDNA.

Anemia, Sideroblastic↗
PubMed1993

Kinetic PCR analysis: real-time monitoring of DNA amplification reactions.

We describe a simple, quantitative assay for any amplifiable DNA sequence that uses a video camera to monitor multiple polymerase chain reactions (PCRs) simultaneously over the course of thermocycling. The video camera detects the accumulation of double-stranded DNA (dsDNA) in each PCR using the increase in the fluorescence of ethidium bromide (EtBr) that results from its binding duplex DNA. The kinetics of fluorescence accumulation during thermocycling are directly related to the starting number of DNA copies. The fewer cycles necessary to produce a detectable fluorescence, the greater the number of target sequences. Results obtained with this approach indicate that a kinetic approach to PCR analysis can quantitate DNA sensitively, selectively and over a large dynamic range. This approach also provides a means of determining the effect of different reaction conditions on the efficacy of the amplification and so can provide insight into fundamental PCR processes.

DNA↗
PubMed1993

Increased level/dose ratio of amphotericin-B in premature infants with renal failure.

We introduced continuous intravenous infusion of amphotericin-B (AMPH-B) to extremely low birthweight (ELBW) infants (< 1000 g) with or without renal failure as a single agent for treating definite or probable systemic candidiasis. The species of Candida isolated from blood or tracheal aspirate or urine were C. albicans in seven infants, C glabrata in two, C. tropicalis in one and C. parapsilosis in one. The minimal inhibitory concentrations (MIC) of AMPH-B required against these isolates were less than 0.2 micrograms/mL except for that against one strain of C. albicans (0.78 microgram/mL). Serum AMPH-B levels were 0.31-0.78 (0.51 +/- 0.14) micrograms/mL when doses of 0.2-0.55 (0.32 +/- 0.11) mg/kg per day were being administered. The serum level was higher than the MIC of each isolate in all but one infant who died of disseminated intravascular coagulation and Candida pneumonia. Another infant died of congenital heart disease. The other nine infants survived. The serum level showed no correlation with the daily dose. The ratio of the serum level to the daily dose (L/D ratio) showed a significant correlation to serum creatinine (r = 0.787) and the linear regression curve followed the equation: L/D ratio = 0.223 x serum creatinine + 1.11 (P < 0.01). Few adverse effects due to AMPH-B were noted. Our data may give a simple reference to serum AMPH-B levels during continuous intravenous infusion from the dose and the serum creatinine level.

Acute Kidney Injury↗
PubMed1992

Characterization of the cytochrome P-450IID subfamily in bovine liver. Nucleotide sequences and microheterogeneity.

To elucidate the molecular mechanisms underlying drug detoxification, the structures of the members of the microsomal cytochrome P-450IID subfamily were analyzed by isolating, mapping and sequencing cytochrome P-450IID (CYP2D) cDNA clones from bovine liver. The screening was performed under nonstringent conditions so that most of the P-450IID subfamily members could be obtained. 114 of the 147 positive clones were classified into four groups on the basis of their restriction-enzyme maps. The maps of the four groups were highly similar, however, the clones of one group contained an insertion of approximately 500 bp in the coding region. Analysis of partial nucleotide sequences of several representative clones from each group showed that the bovine P-450IID subfamily in liver consisted of several, not many, highly similar members, differing by less than 7% in their nucleotide sequences. The location of the insertion found in the minor group corresponded to intron 7 and the GT/AG rule was found at the exon/intron boundary, suggesting that intron 7 was retained in this group. The complete nucleotide sequences of two clones from the major group were examined to determine the structures of the P-450IID subfamily in bovine liver. A full-length cDNA clone (1615 bp) and a partial cDNA clone (1538 bp) contained open reading frames encoding 500 and 487 amino acid residues, respectively. The partial clone lacked the nucleotide sequence corresponding to the first 13 N-terminal amino acid residues. The deduced amino acid sequences of the two clones were 98% similar, and 80% and 68% similar to those from human CYP2D6 and rat CYP2D1, respectively. Comparisons of the amino acid sequences of the P-450IID subfamily members showed the highly conserved C-terminal region of their molecules and the high similarity between the members in one species, especially in cattle and man.

Amino Acid Sequence↗
PubMed1992

Structures of four new triterpenoid oligoglycosides: DS-penaustrosides A, B, C, and D from the sea cucumber Pentacta australis.

Two new non-holostane-type triterpenoid oligoglycosides, DS-penaustrosides A [1] and B [2], were isolated from the solvolysate of a crude glycoside fraction obtained from a sea cucumber Pentacta australis, together with two holostane-type glycosides, DS-penaustrosides C [3] and D [4]. The structure of 1-4 have been elucidated on the basis of spectral and chemical evidence.

Animals↗
PubMed1992

Simultaneous amplification and detection of specific DNA sequences.

We have enhanced the polymerase chain reaction (PCR) such that specific DNA sequences can be detected without opening the reaction tube. This enhancement requires the addition of ethidium bromide (EtBr) to a PCR. Since the fluorescence of EtBr increases in the presence of double-stranded (ds) DNA an increase in fluorescence in such a PCR indicates a positive amplification, which can be easily monitored externally. In fact, amplification can be continuously monitored in order to follow its progress. The ability to simultaneously amplify specific DNA sequences and detect the product of the amplification both simplifies and improves PCR and may facilitate its automation and more widespread use in the clinic or in other situations requiring high sample throughput.

Alleles↗
PubMed1992

Preferential PCR amplification of alleles: mechanisms and solutions.

The preferential PCR amplification of one allele relative to another in a heterozygous sample could result in an incorrect or ambiguous genetic typing of that sample. There are several mechanisms that could potentially lead to such preferential PCR amplification. First, preferential amplification can result from significant GC% differences between alleles if the conditions of the reaction (denaturation temperature (Tden), duration at the Tden' salt and co-solvent concentrations, etc.) allow the denaturation of one allele but not the other (differential denaturation). For example, the DQa1.1, -1.2, and -1.3 alleles of the HLA-DQa locus do not amplify at a Tden < 89 degrees C; these same conditions still allow amplification of the DQa2, -3, and -4 alleles. However, no differences in amplification efficiency were found between the different HLA-DQa alleles when the Tden was set at the recommended Tden of 94 degrees C, even after as many as 102 cycles of amplification. Second, for PCR-based genetic typing systems in which the PCR products from different alleles differ in length, preferential amplification of the shorter allelic product can occur. Experiments in which the variable number tandem repeat (VNTR) marker D17S5 (YNZ22) was amplified under various conditions suggest that the smaller allelic products are amplified preferentially when Taq polymerase is limiting. Preferential amplification of VNTR alleles can also occur if the target DNA is sufficiently degraded. Third, when the initial number of genomes sampled is very small, stochastic fluctuation in the number of copies of each allele can result in what appears to be preferential amplification. Finally, less efficient priming of DNA synthesis of one allele versus another can occur because of mismatches between the primer and the specific allelic template, resulting in preferential amplification of the other allele. General strategies to avoid preferential amplification are discussed.

Alleles↗
PubMed1992

A family with haemolytic anaemia and three beta-globins: the deletion in haemoglobin Atlanta-Coventry (beta 75 Leu----Pro, 141 Leu deleted) is not present at the nucleotide level.

Analyses of haemoglobin from a family with an unstable haemoglobin haemolytic anaemia demonstrated that the affected individuals had three beta-globins, namely, normal (beta A), Atlanta (beta At) with a mutation of beta 75 Leu----Pro, and beta-Atlanta-Coventry (beta At-Co) with mutation of beta 75 Leu----Pro and beta 141 Leu deleted. These were present in the ratio 66:23:11 respectively. The structure of the beta-globin cluster, however, was found to be normal by Southern blotting; also cytogenetic analysis failed to show any abnormality. DNA sequence analyses demonstrated the presence of the beta At mutation in genomic DNA isolated from leucocytes but the Coventry deletion of 141 Leu in beta At-Co was not present in genomic DNA. PCR amplification of the beta-globin cDNA and direct sequencing of the product also failed to demonstrate the Coventry deletion. Thus, it appears that the absence of 141 Leu in the beta At-Co globin is a consequence of the beta At mutation in these patients and that both beta At and beta At-Co are the product of a single gene. This unusual conclusion is paralleled in the bizarre case of Hb Vicksburg where the deletion of a leucine at beta 75 is not coded for in genomic DNA.

Anemia, Hemolytic↗
PubMed1992

In vitro conversion of surfactant subtypes is altered in alveolar surfactant isolated from injured lungs.

Pulmonary alveolar surfactant can be separated into different subtypes on the basis of their buoyant densities. These subtypes have been characterized as ultraheavy and heavy forms, which are surface-active, and light forms, which are less surface active. The ratio of these subtypes was altered in an animal model of acute lung injury that contributed to the physiologic abnormalities. We used an in vitro method of surface-area cycling to compare conversion of heavy subtypes isolated from injured and from normal lungs. Lung injury was induced in adult rabbits with a subcutaneous injection of N-nitroso-N-methylurethane (NNMU). Conversion of NNMU-injured heavy subtypes to light subtypes was significantly greater than normal heavy subtype conversion at each time point studied from 60 to 180 min of cycling (p less than 0.01). Surfactant protein A (SP-A) was added to heavy subtypes, with no effect on conversion when 1.5% SP-A was added, but the addition of 4.5, 10.5, and 22.5% caused complete conversion to ultraheavy forms with no cycling. With subsequent cycling, there was greater conversion from ultraheavy to lighter subtypes for normal surfactant material than for NNMU-injured material (p less than 0.05). We conclude that the altered ratio of surfactant subtypes in the alveolar lavage of injured lungs was due to a greater conversion of these subtypes within the alveolar space. Furthermore, SP-A may play an important role in the metabolism of alveolar surfactant both in normal and in injured lungs.

Animals↗