CYP51-like gene of Mycobacterium tuberculosis actually encodes a P450 similar to eukaryotic CYP51

A CYP51-like gene (Z80226) of Mycobacterium tuberculosis was expressed in Escherichia coli. The product exhibited absorption spectra characteristic of P450. The expressed P450 formed a stoichiometric complex with ketoconazole, one of the specific ligands of CYP51. These findings indicate that the CYP51-like gene of M. tuberculosis actually encodes a P450 having active-site environments similar to those of CYP51, confirming the predicted orthologous nature of this gene to eukaryotic CYP51. Although eukaryotic CYP51s are membrane-binding proteins, the expressed product was accumulated only in the soluble fraction of the host cells.

[Treatment of hepatosplenic candidiasis with liposomal amphotericin B in a patient with acute leukemia; a case report of the experience of use of liposomal amphotericin B]

We report a 26-year-old male patient with acute myelocytic leukemia and hepatosplenic candidiasis during his clinical course. His hepatosplenic candidiasis was refractoty to itraconazole and fluconazol. He developed serious side-effect such as renal dysfunction, when conventional amphotericin B was given. Then he was treated with liposomal amphotericin B (Abelcet). This therapy was safe and effective for him. He was able to be treated with 3075 mg of a liposomal amphotericin B. This was ten times as much as the dose of conventional amphotericin B which was given earlier until amphotericin B was stopped because of renal dysfunction. Liposomal amphotericin B seems to be a safe and effective therapy for systemic fungal infectin and should be considered more in Japan.

Leucocyte distribution during sevoflurane anaesthesia

We have examined if sevoflurane anaesthesia per se modified the number of circulating leucocytes in humans. Fifty-nine patients undergoing elective surgery were anaesthetized with sevoflurane in oxygen. The inhaled concentration was increased gradually to 5% and maintained for 20 min. Arterial blood samples were obtained before induction of anaesthesia and at 20 min. While the total number of leucocytes remained constant, circulating neutrophils decreased (mean 3370 (SD 1030) mm-3 to 3170 (940) mm-3; P < 0.01) and lymphocytes increased (1870 (520) mm-3 to 2040 (580) mm-3; P < 0.01). We conclude that high concentrations of sevoflurane modified the distribution of leucocytes in anaesthetized patients.

[Factitious anemia with severe iron deficiency caused by self-venesection]

A 22-year-old unmarried female student of nurse school was admitted to our hospital because of hypochromic anemia and fever of unknown origin. She was diagnosed as having iron-deficiency anemia and was treated with iron, but progressive anemia recurred periodically. In particular, rapidly progressive anemia was observed after the patient stayed overnight, so we strongly suspected factitious anemia. A search of her locker in the sickroom and her room at home revealed many syringes, injection needles and a bottle of blood. Factitious anemia was diagnosed and she confessed to self blood-drawing. After a psychiatric consultation, anemia tended to to resolve gradually. However she did not go to the hospital after 6 months from her discharge. Physicians should consider factitious anemia in a patient with severe chronic hypochromic anemia who dose not respond to adequate iron therapy, particularly in a patient with medical training.

Dietary cystine and liver triacylglycerols in rats: effects of dietary lysine and threonine

Addition of excess cystine to a wheat gluten diet did not alter rat liver triacylglycerols or serum cholesterol. However, if the cystine-enriched diet was supplemented with lysine and threonine, rats accumulate triacylglycerols and show increased serum cholesterol. Increases in hepatic triacylglycerols can be prevented by the further addition of methionine. This diet further increases serum cholesterol. We conclude that accumulation of triacylglycerols in the liver might be due to an increased methionine requirement, induced by the addition of excess cystine, and therefore to choline deficiency.

A novel point mutation in an acceptor splice site of intron 32 (IVS32 A-12-->G) but no exon 3 mutations in the glycogen debranching enzyme gene in a homozygous patient with glycogen storage disease type IIIb

Genetic deficiency of the glycogen-debranching enzyme (debrancher) causes glycogen storage disease type III (GSD III), which is divided into two subtypes: IIIa and IIIb. In GSD IIIb, glycogen accumulates only in the liver, whereas both liver and muscles are involved in GSD IIIa. The molecular basis for the differences between the two subtypes has not been fully elucidated. Recently, mutations in exon 3 of the debrancher gene were reported to be specifically associated with GSD IIIb. However, we describe a homozygous GSD IIIb patient without mutations in exon 3. Analysis of the patient's debrancher cDNA revealed an 11-bp insertion in the normal sequence. An A to G transition at position -12 upstream of the 3' splice site of intron 32 (IVS 32 A-12-->G) was identified in the patient's debrancher gene. No mutations were found in exon 3. Mutational analysis of the family showed the patient to be homozygous for this novel mutation as well as three polymorphic markers. Furthermore, the mother was heterozygous and the parents were first cousins. The acceptor splice site mutation created a new 3' splice site and resulted in insertion of an 11-bp intron sequence between exon 32 and exon 33 in the patient's debrancher mRNA. The predicted mutant enzyme was truncated by 112 amino acids as a result of premature termination. These findings suggested that a novel IVS 32 A-12-->G mutation caused GSD IIIb in this patient.

Structural and evolutionary studies on sterol 14-demethylase P450 (CYP51), the most conserved P450 monooxygenase: I. Structural analyses of the gene and multiple sizes of mRNA

The structure of rat CYP51 gene encoding sterol 14-demethylase was examined. The CYP51 gene spanned about 18 kb and contained 10 exons. The copy number of CYP51 in the rat genome was determined to be one. In addition, one CYP51 processed (intron-less) pseudogene covering the coding and ca. 600-bp 3'-noncoding sequences of CYP51 cDNA was found in the rat genome. Multiple transcription initiation sites were predicted by primer extension and 5'-RACE methods using poly(A)+ RNA from liver, ovary, and testis, and the major ones were located at 126 and 123 nucleotides upstream from the initiation ATG codon. The primer extension also showed several minor sites around the major ones. In addition to these sites, other minor initiation sites were also predicted at around 330 and 460 nucleotides upstream from the initiation ATG codon. No TATA box was found in the putative promoter region, but multiple GC boxes were found around the cap sites, supporting the previously inferred housekeeping nature of CYP51 gene and the existence of the multiple transcription initiation sites. A few consensus transcription regulatory elements such as CRE were found in the 5'-flanking region. Four polyadenylation signals were found in the 3'-noncoding region by the 3'-RACE method. Three of them were used to generate 3.1-, 2.7-, and 2.3-kb mRNAs in liver and ovary. The remaining one was used only in testis to generate 1.9-kb mRNA having an unusually short trailer sequence, suggesting a specific regulatory mechanism for generating CYP51 mRNA in testis different from that in liver and ovary.

Experience of expandable metallic stents for central airway obstruction

The aim of this study was to investigate retrospectively the efficacy of expandable metallic stents (EMSs) for severe respiratory distress in patients with central airway obstruction. Twenty patients with central airway obstructions were treated with an EMS. An intraluminal stricture was present in 15 and an extraluminal stricture in 5 patients. Of the 15 patients with intraluminal stenosis, 11 exhibited symptomatic improvement. All 11 patients had tumor infiltration occupying less than 50% of the endoluminal diameter. The other four patients with intraluminal stenosis had tumor infiltration occupying > 50% of the endoluminal diameter and demonstrated no improvement. All five patients with extraluminal stenosis were improved. EMS is useful for an extraluminal stricture in the central airway and the effect of EMS for intraluminal stenosis is related to the degree of infiltration and of tumor progression itself.

Structural and evolutionary studies on sterol 14-demethylase P450 (CYP51), the most conserved P450 monooxygenase: II. Evolutionary analysis of protein and gene structures

Phylogenetic analyses based on protein sequence data indicated that sterol 14-demethylase P450 (CYP51) and bacterial CYP51-like protein were joined into a distinctive evolutionary cluster, CYP51 cluster, within the CYP protein superfamily. The most probable branch topology of the CYP51 phylogenetic tree was (bacteria, (plants, (fungi, mammals))), which is comparable to the phylogeny of major kingdoms of living matter, suggesting that CYP51 has been conserved from the era of prokaryotic evolution. This may be strong evidence supporting the prokaryotic origin of P450. Structure of flanking regions and the number and insertion sites of introns are quite different between mammalian and fungal CYP51s. This fact indicates that different mechanisms are operative in evolution of protein sequences and gene structures. CYP51 is the first example violating the well-documented rule that the basic structure of a gene, including intron insertion sites, is well conserved in each P450 family. One CYP51 processed a pseudogene was found in rat genome. Nonsynonymous nucleotide divergence observed between the pseudogene and CYP51 cDNA was less than one-fifth of the synonymous divergence. This unusually low rate of nonsynonymous nucleotide changes in the pseudogene suggests that it may be derived from another CYP51, which might have been active for a significant duration in the past.

Treatment of head and neck cancers with BRMs--prolongation of survival

It has been reported that immunologic function is deteriorated in head and neck cancer patients by primary therapies such as surgery, irradiation and chemotherapy or tumor itself. As previously described by us, immunologic dysfunction in such patients may be recovered by treatment with BRMs. In the present study, we investigated the effects of BRMs on survival of patients who had primarily been treated in our clinic. Fifty-one patients (23 patients; Stage I or Stage II, 28 patients; Stage III or Stage IV) were treated with BRMs (BRM group), and 49 patients (22 patients; Stage I or Stage II, 27 patients; Stage III or Stage IV) were employed as controls (Control group). The results obtained were as follows: (1) In patients of all Stages, the survival period was significantly (p < 0.05) longer in BRM group than in Control group; (2) The survival periods of patients of Stage I or Stage II were not different between the groups; and (3) The survival period of BRM group was significantly (p < 0.05) longer than that of Control group in patients of Stage III or Stage IV. There were observed more patients in BRM group who survived for a prolonged period. These results suggest that BRMs may be useful for recovering immunologic function in head and neck cancer patients particularly of Stage III or Stage IV who usually receive multimodality therapy.

Different responses of apolipoprotein A-I, A-IV, and B gene expression during intestinal adaptation to a massive small bowel resection in rats

Gene expression of apolipoproteins (apo) A-I, A-IV, and B, the predominant protein components of chylomicrons, was investigated in the residual ileum after a massive small bowel resection in rats. A Northern blot analysis showed that the apo A-IV mRNA level, but not the apo A-I and B mRNA levels, in the ileum was significantly higher in the resected rats than in the sham-operated rats 24 h and 2 wk post-surgery. RT-PCR coupled with a primer extension assay revealed that the apo B-48 mRNA/apo B-100 mRNA ratio, i.e., apo B mRNA editing, in the ileum was unchanged by the resection. It is thus concluded that, among the major intestinal apolipoproteins, apo A-IV is the only one whose gene expression is influenced by loss of the proximal intestine.

Stimulating effect of ileal pancreaticobiliary secretion on ileal apolipoprotein A-IV mRNA expression in fasted rats

The effect of pancreaticobiliary secretion on the intestinal expression of the apo A-IV gene was examined in fasted rats. Pancreaticobiliary diversion, but not biliary diversion alone, into the ileum increased the ileal apo A-IV mRNA expression by 24 h post-operation. Jejunal apo A-IV mRNA was reduced by biliary exclusion. The data suggest that the biliary constituent plays an important role in the apo A-IV gene expression in the entire length of the small intestine, and that up-regulation of the apo A-IV gene requires exocrine pancreatic in addition to biliary secretion.

A G+1 to C mutation in a donor splice site of intron 2 in the apolipoprotein (apo) C-II gene in a patient with apo C-II deficiency. A possible interaction between apo C-II deficiency and apo E4 in a severely hypertriglyceridemic patient

Familial apolipoprotein C-II (apo C-II) deficiency is an autosomal recessive genetic disorder characterized by fasting hypertriglyceridemia and accumulation of chylomicrons in the plasma. To elucidate the genetic defect, the apo C-II gene of a neonatal Japanese patient (C-IITokyo) was analyzed. Nucleotide sequence analysis showed a G+1 to C transversion at the donor splice site of intron 2 (INT2 G+1 to C). Restriction fragment length polymorphism analyses of the patient's family members with Hph I showed that the patient was homozygous and the parents were heterozygous for the INT2 G+1 to C mutation. Although consanguinity could not be demonstrated, haplotype analysis of the C-II gene revealed the identity of the patient's alleles on the mutation, suggesting that the parents had a common Japanese ancestor. Sequence analysis of the patient's cDNA isolated from peripheral blood lymphocytes revealed that the INT2 G+1 to C mutation causes skipping of exon 2, which encodes the initiation codon, and results in deficiency of apo C-II proteins. The outstanding feature of our patient was that he showed severe hypertriglyceridemia beginning in the neonatal period, a feature not reported in a case of apo C-II deficiency (C-IIHamburg) with the same mutation as our patient. A previous report of another case of apo C-II deficiency (C-IIToronto) suggested that the apo E4 isoform is associated with higher levels of plasma triglycerides in subjects heterozygous for the apo C-II mutation. Determination of the apo E isoform of our patient revealed that apo E4 was coinherited with the INT2 G+1 to C mutation, whereas the apo E isoform has been reported to be E2/3 in C-IIHamburg. We speculate that apo E4/4 aggravated the hypertriglyceridemia in our patient with apo C-II deficiency.

Identification of a point mutation (G727T) in the glucose-6-phosphatase gene in Japanese patients with glycogen storage disease type 1a, and carrier screening in healthy volunteers

Glycogen storage disease type 1a (GSD 1a) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (G6Pase). We analyzed the G6Pase gene of two unrelated Japanese families with GSD 1a. DNA sequencing of all five exons and exon-intron junctions revealed a G-to-T transversion at nucleotide 727 (G727T) in exon 5, which has been previously reported to cause abnormal splicing. Family studies using mismatch PCR showed that three patients were homozygous for the G727T mutation, while the parents were heterozygous. To investigate allele frequencies, we screened 216 Japanese healthy volunteers and found one asymptomatic carrier. Our findings suggest that the G727T mutation may be prevalent in Japan.

Thymolipoma: clinical and pathological features--report of three cases and review of literature

We report three recently resected cases of thymolipoma. Two cases (case 2 and 3) were female and the other (case 1) was male. The age of these three were 41 years, 63 years, and 29 years, respectively. While two cases (case 1 and 2) were asymptomatic, the other (case 3) had associated myasthenia gravis. Preoperative examination in each case was performed using chest CT scan or chest MRI, or both. Only one case (case 1) was diagnosed as thymolipoma preoperatively, and this was by a chest MRI showing the mass in continuity with the thymus. The diagnosis of each lesion was confirmed histologically by their composition of lobules of mature adipose tissue with minute islands of thymic tissue consisting of epithelial cells, lymphocytes, and Hassall's bodies.

A novel missense mutation (Asn5-->Ile) in lecithin: cholesterol acyltransferase (LCAT) gene in a Japanese patient with LCAT deficiency

We identified a novel missense mutation in the lecithin:cholesterol acyltransferase gene in a new case of lecithin:cholesterol acyltransferase (LCAT) deficiency. The patient was a 64-year-old diabetic Japanese male who showed an extremely low level of serum high-density lipoprotein-cholesterol, corneal opacities, anemia, and proteinuria. Both the patient's LCAT activity and mass were markedly low. DNA sequence analysis of the LCAT gene showed an A-to-T transition at base 97 in exon 1, and predicted a change in asparagine to isoleucine at the 5th amino acid of the protein. Restriction analysis of polymerase chain reaction-amplified DNA using Ase I showed that the patient was homozygous for this mutation. Our results suggested that asparagine 5 was an important amino acid and substitution with isoleucine caused marked reduction of LCAT activity and mass, resulting in LCAT deficiency.

Lanosterol 14-demethylase activity expressed in rat brain microsomes

The occurrence of sterol 14-demethylase in rat brain microsomes was confirmed. The brain microsomes from adult rats converted lanosterol into its 14-demethylated products, 4,4-dimethylcholesta-8, 24-dienol, and 4,4-dimethylcholesta-8,14,24-trienol, in the presence of NADPH and molecular oxygen. This metabolism of lanosterol was inhibited by carbon monoxide and ketoconazole, a potent inhibitor of sterol 14-demethylase P450 (P45014DM or CYP51). These facts indicated the occurrence of lanosterol 14-demethylation in rat brain microsomes and its dependency on P45014DM. A representative value of the lanosterol demethylase activity of the brain microsomes was 8.4 pmol/min/mg protein or 640 pmol/ min/nmol of total P450. The former was about one-thirteenth of the corresponding value observed with liver microsomes from the same rats, while the latter was 4-times higher than the corresponding value obtained with the liver microsomes. This fact suggested that the ratio of P45014DM to other P450 species was higher in brain than in liver. Lanosterol 14-demethylation is situated at the root of the sterol-biosynthetic branch of the mevalonic acid pathway. Therefore, the present finding enzymologically supports the existence of the sterol biosynthetic pathway in brain.

A novel donor splice site mutation in the glycogen debranching enzyme gene is associated with glycogen storage disease type III

Analysis of glycogen debranching enzyme (debrancher) cDNA from a patient with glycogen storage disease type III revealed a deletion of 124 base pairs. A donor splice site mutation (IVS G+1 to T) was identified in the patient's debrancher gene, which caused exon skipping of the upstream exon and resulted in a truncated enzyme due to premature termination. Mutational analysis of the patient's family showed that this point mutation was inherited from the father. Southern blot analysis of the patient's genomic DNA showed an additional, unique EcoRI fragment of 5.8 kb, which was inherited from the mother. These results suggested that the patient was a compound heterozygote for the donor splice site mutation, which is the first identified in the debrancher gene, and had a genetic defect relating to an aberrant 5.8-kb EcoRI fragment.

Sterol 14-demethylase P450 activity expressed in rat gonads: contribution to the formation of mammalian meiosis-activating sterol

Sterol 14-demethylase P450 (P45014DM)-dependent formation of 4,4-dimethylcholesta-8,14,24-trienol, that has been reported for a mammalian meiosis-activating sterol, in rat ovaries was confirmed. Transient elevation of ovarian P45014DM activity, that might be related to the female sexual cycle of rat, was observed. The P45014DM activity of immature ovaries was induced by pregnant mare's serum gonadotropin. These facts suggest the contribution of ovarian P45014DM to the gonadotropin-dependent formation of the meiosis-activating sterol, and provide a clue to understanding the mechanism how gonadotropins initiate the resumption of meiosis of mammalian oocytes. It was also found that rat testicular P45014DM participated in the production of 4,4-dimethylcholesta-8,24-dienol that was reported for another meiosis-activated sterol isolated from bull testes.

Sterol 14-demethylase P450 (P45014DM*) is one of the most ancient and conserved P450 species

To determine the orthology of sterol 14-demethylase (P45014DM), the only known P450 enzyme distributed widely in eukaryotes with a conserved metabolic role, the full-length amino acid sequences of rat and human P45014DMs were determined from the cloned cDNA sequences, and compared with those of the corresponding fungal proteins (CYP51). The amino acid identity value between given pairs of P45014DMs ranged from 93% (human/rat) to 39% (human or rat/Saccharomyces cerevisiae). All the P45014DMs formed a single cluster in a phylogenetic tree constructed from representative P450 protein sequences currently available. The nearest neighbors to the P45014DM cluster in the phylogenetic tree were CYP7 (cholesterol 7 alpha-hydroxylase) and CYP8 (prostacyclin synthase), and the divergence point of fungal and mammalian P45014DMs was clearly more recent than that of P45014DM and CYP7/CYP8. These lines of evidence show that fungal and mammalian P45014DMs are really orthologous. This is the first example of orthologous P450s occurring in distinct kingdoms. P45014DM may be an ancient P450 which arose before the divergence of major eukaryotic branches and has been conserved throughout evolution. The amino acid identity value (93%) between human and rat P45014DMs was comparable to those observed for some housekeeping enzymes. In addition, a processed pseudogene of P45014DM was found in a rat genomic DNA library, suggesting the expression of P45014DM in germ line cells. These facts suggest that P45014DM may be a housekeeping enzyme essential for the viability of mammals.

Protein kinase C-dependent down-regulation of basic fibroblast growth factor (FGF-2) receptor by phorbol ester and epidermal growth factor in porcine granulosa cells

The regulation of the basic fibroblast growth factor (bFGF, or FGF-2) receptor on porcine granulosa cells was studied. Receptor levels before and after cell differentiation in vivo and in vitro did not show any significant changes. Dibutyryl cAMP and the protein kinase A (PKA) inhibitor H-8 had no effect on bFGF binding. These results suggest that PKA was not involved in the receptor expression. Treatment of the granulosa cells with phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, progressively decreased the number of bFGF receptors to about 20% of their initial levels after 8 h, and this effect occurred in a concentration- and time-dependent manner. Similarly, synthetic diacylglycerol also inhibited bFGF binding. The highly specific PKC inhibitor GF109203X completely prevented the reduction of bFGF binding by PMA and diacylglycerol. Kinetic analyses of the turnover of cell surface bFGF receptors in the presence of cycloheximide showed that PMA accelerated loss of receptors from the cell surface, suggesting the enhanced receptor internalization by PMA resulting in the receptor reduction. PMA did not influence steady-state FGF receptor messenger RNA levels. PMA induced an increased PKC activity in the membrane fraction, and among PMA sensitive PKC alpha, beta II, delta and epsilon, only PKC alpha was readily detected by immunoblotting and translocated to the membrane fraction. PMA-pretreated cells showed negligible effect on c-fos messenger RNA induction in response to bFGF stimulation, indicating a functional reduction of receptors. When cells were incubated with epidermal growth factor, receptor levels were reduced, but this effect was not observed in the presence of GF109203X. These results suggest that the bFGF receptor in porcine granulosa cells is regulated by the PKC, not PKA, pathway in an isoenzyme-specific fashion and that its possible mechanism may involve regulation of receptor internalization.