Pharmacist-led multi-faceted intervention in an antimicrobial stewardship programme at a dental university hospital in Japan

BACKGROUND

Antimicrobials are commonly prescribed in dentistry. However, inappropriate antimicrobial prescriptions are common in this field. Optimizing antimicrobial prescriptions in dentistry requires an effective strategy for modifying prescribing behaviour.

AIM

To assess the efficacy of pharmacist-led multi-faceted intervention for the proportion of monthly antimicrobial prescriptions in each drug group per 100 oral antimicrobial prescriptions.

METHODS

A before-after trial was performed at a university hospital outpatient dental clinic. A pharmacist-led, multi-faceted intervention, including immediate and direct feedback to the prescribers, an explanation of the rules of antimicrobial prescriptions for patients with penicillin allergy, tutorials for dentistry students, and a review of hospital-approved antimicrobials, was implemented from April 2017 to March 2022. Antimicrobials were classified into eight groups, namely, penicillins, first- and second-generation cephalosporins, third-generation cephalosporins, fluoroquinolones, macrolides, clindamycin, carbapenem, and others.

FINDINGS

In total, there were 2,643,988 visits to the outpatient dental clinic during the study period. The monthly mean proportion of prescriptions for penicillins increased from 45.6 to 84.1 per 100 oral antimicrobial prescriptions (P<0.001) while that of third-generation cephalosporins decreased from 43.0 to 7.3 (P<0.001) from the pre-intervention to the intervention period. Moreover, the monthly mean proportion of fluoroquinolones, macrolides, and carbapenems decreased from 11.2 to 7.44 (P<0.001).

CONCLUSION

The intervention modified dentists' antimicrobial prescribing behaviours, leading to an immediate increase in the number of monthly prescriptions for penicillins and a simultaneous decrease in the number of monthly prescriptions for third-generation cephalosporins and other broad-spectrum, oral antimicrobials.

Reduction of Pneumocystis jirovecii pneumonia and bloodstream infections by trimethoprim-sulfamethoxazole prophylaxis in patients with rheumatic diseases

Objective: Trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis against Pneumocystis jirovecii pneumonia (PJP) is routinely administered to patients with rheumatic diseases in Japan. The present study aimed to evaluate the effect of TMP/SMX prophylaxis on PJP and non-central line-associated bloodstream infections (BSIs) in patients receiving high-dose glucocorticoids for the treatment of rheumatic diseases.Method: This study enrolled patients who were admitted between 1 October 2003 and 31 March 2018 and began high-dose glucocorticoid therapy for rheumatic diseases during hospitalization. The observation period was 4 months from the commencement of high-dose glucocorticoid therapy. The effect of TMP/SMX prophylaxis on PJP and non-central line-associated BSI was analysed.Results: Of the 437 patients included in the study, 376 received TMP/SMX prophylaxis and 61 patients did not. During the observation period, TMP/SMX prophylaxis was discontinued in 76 patients (20.2%). Three PJP cases (0.7%) occurred. Among the 399 patients included in our analysis of non-central line-associated BSI, eight experienced non-central line-associated BSI (2.0%). Among the covariates, TMP/SMX prophylaxis was associated with reduced PJP and non-central line-associated BSI incidence [odds ratio (OR) 0, 95% confidence interval (CI) 0.00-0.38, and OR 0.08, 95% CI 0.01-0.42, respectively].Conclusion: Routine TMP/SMX prophylaxis reduced the incidence of both PJP and BSI in patients with rheumatic diseases undergoing high-dose glucocorticoid therapy.

Impact of inadequate initial antimicrobial therapy on mortality in patients with bacteraemic cholangitis: a retrospective cohort study

OBJECTIVES

Acute cholangitis is a common cause of bacteraemia resulting in severe sepsis or septic shock. The impact of the appropriate initial antimicrobial therapy on short-term mortality in bacteraemic cholangitis has not been well investigated.

METHODS

We conducted a retrospective cohort study of patients with bacteraemic cholangitis at two large tertiary care centres in Tokyo, Japan between 2009 and 2015. We determined the factors associated with 30-day all-cause mortality from the date of drawing the first positive blood culture, using a multivariate logistic regression analysis.

RESULTS

We identified 573 patients with bacteraemic cholangitis (median age, 77 years; male, 58.3%). The 30-day all-cause mortality rate was 6.6% (38/573). Inadequate initial antimicrobial therapy occurred in 133 (23.2%) patients. Factors associated with 30-day all-cause mortality included the Charlson co-morbidity index score >3 (adjusted odds ratio (aOR) 4.12; 95% CI 1.18-14.38), jaundice (total bilirubin >2.5 mg/dL) (aOR 3.39; 95% CI 1.46-7.89), septic shock within 48 h of the first positive blood culture (aOR 3.34; 95% CI 1.42-7.89), biliary obstruction due to hepatobiliary malignancy (aOR 8.00; 95% CI 2.92-21.97), and inadequate initial antimicrobial therapy (aOR 2.78; 95% CI 1.27-6.11).

CONCLUSIONS

Inadequate initial antimicrobial therapy was an important, modifiable determinant of survival.

Statistical and probabilistic approaches to confidence intervals of linear calibration in liquid chromatography

The aim of this paper is to compare the reliability of two approaches to estimate the 95% confidence intervals of linear calibration in real situations. One is the statistical approach, which is well known in statistics, and the other is the probabilistic approach, which is based on a theory to predict the precision of instrumental analyses mainly from signal and noise, called FUMI (Function of Mutual Information) theory. The high-performance liquid chromatographic determination of quisalofop and maltose is taken as an example. Calibration lines obtained under the same experimental conditions are superimposed on the 95% confidence intervals to investigate whether the resulting confidence intervals can include all the calibration lines reasonably. A pair of 95% confidence intervals (upper and lower limits) can be calculated from each calibration line, but varies from calibration line to calibration line, although obtained under the same experimental conditions. The variability and reliability of the 95% intervals are also examined.

[Chlormadinone Acetate Reference Standard (Control 961) of National Institute of Health Sciences]

The raw material for chlormadinone acetate was tested for preparation of the "Chlormadinone Acetate Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 215. 3 degrees C; UV spectrum, lambda max = 283.5 nm; IR spectrum, the same as that of JP Chlormadinone Acetate Reference Standard (Control 885); optical rotation, [alpha]20D = -13.0 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography, two impurities were detected; loss on drying, 0.01%; assay, 99.4% by spectrophotometry and 99.5% by HPLC. Based on the above results, the raw material was authorized as the Chlormadinone Acetate Reference Standard (Control 961) of National Institute of Health Sciences (Japanese Pharmacopoeia).

[Epinephrine Bitartrate Reference Standard (Control 951) of National Institute of Health Sciences]

The raw material for epinephrine bitartrate was tested for preparation of the "Epinephrine Bitartrate Reference Standard (Control 951)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 148.6 degrees C (decomposition); UV spectrum, lambda max = 279 nm; IR spectrum, the same as that of JP Epinephrine Bitartrate Reference Standard (Control 792); optical rotation, [alpha]20D = -52.8 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography, no impurity was detected; loss on drying, 0.01%; assay, 99.6% by potentiometric titration, 100.3% by spectrophotometry. Based on the above results, the raw material was authorized as the Epinephrine Bitartrate Reference Standard (Control 951) of National Institute of Health Sciences (Japanese Pharmacopoeia).

[dl-Camphor Reference Standard (Control 961) of National Institute of Health Sciences]

The raw material of dl-camphor was examined for the preparation of the "dl-Camphor Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained are as follows: UV spectrum, lambda max = 290 nm; IR spectrum, the same as that of the present JP Camphor Reference Standard (Control 953); melting point, 179.1 degrees C; purity test by gas-chromatography (GC), three kinds of impurities were detected; assay by GC, 99.8%. Based on the above results, the candidate raw material was authorized as the dl-Camphor Reference standard (Control 961) National Institute of Health Sciences (Japanese Pharmacopoeia).

[Analysis of B-3 desamido insulin in human insulin preparations by HPLC]

The content of A-21 desamido insulin (A-21 DI) and B-3 desamido insulin (B-3 DI) in human insulin preparations was measured by new RP-HPLC method using a neutral eluent (pH 6.5). Sometimes the content of B-3 DI in human insulin preparations was about two times larger than that of A-21 DI. In particular, in the case of neutral insulin injection, the content of B-3 DI has increased remarkably as the increase of total desamido content. The content of B-3 DI obtained by the new RP-HPLC method will open the new aspect of the impurity test for insulin preparations.

[Hydrocortisone Acetate Reference Standard (Control 961) of National Institute of Health Sciences]

The raw material of hydrocortisone acetate was tested for the preparation of the "Hydrocortisone Acetate Reference Standard (Control 961)". Analytical data obtained were as follows: IR spectrum, specific absorption wave numbers at 3428, 1748, 1723, 1631, and 1375 cm-1; specific absorbance, E1cm1% (242 nm) = 406; thin-layer chromatography, no impurities were detected until 0.05 microgram; high-performance liquid chromatography (HPLC), 2-3 impurities were detected and the amount of the total impurities was estimated to be about 0.2%; assay by HPLC, 100.7%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 961).

[Estradiol Reference Standard (Control 961) of National Institute of Health Sciences]

The raw material for estradiol was examined for preparation of the "Estradiol Reference Standard (Control 961)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 179.1 degrees C; UV spectrum, lambda max = 281 nm; IR spectrum, the same as that of the Estradiol Reference Standard of National Institute of Health Sciences (Control 931); optical rotation, [alpha]20D = +79.5 degrees; thin-layer chromatography, one impurity was detected; high-performance liquid chromatography (HPLC), a trace amount of three impurities were detected; loss on drying, 3.17%; assay, 99.4% by UV spectrophotometry and 99.0% by HPLC. Based on the above results, the raw material was authorized as the Estradiol Reference Standard (Control 961) of National Institute of Health Sciences.

[Riboflavin Reference Standard (Control 951) of National Institute of Health Sciences]

The raw material for riboflavin was tested for preparation of the "Riboflavin Reference Standard (Control 951)" of National Institute of Health Sciences. Analytical data obtained were as follows: melting point, 284.6 degrees C (decomposition): specific absorbance, E1cm1% = 857 (267 nm), 277 (373 nm), 326 (445 nm); IR spectrum, the same as that of JP Riboflavin Reference Standard (Control 921); optical rotation, [alpha]20D = -135.6 degrees; thin-layer chromatography, three impurities were detected; high-performance liquid chromatography, a small amount of 10 impurities were detected: loss on drying, 0.10%; assay, 100.4% by spectrophotometry. Based on the above results, the raw material was authorized as the Riboflavin Reference Standard (Control 951) of National Institute of Health Sciences (Japanese Pharmacopoeia).

[Lysozyme Reference Standard (Control 951) of the National Institute of Health Sciences]

The "Lysozyme Reference Standard (Control 951)" of the National Institute of Health Sciences was prepared. The lysozyme potency of the standard material was assayed against the Lysozyme Reference Standard (Control 915) by two turbidimetric methods using the drycells of Micrococcus luteus as the substrate. The potency of the standard material was in satisfactory agreement with that of Lysozyme Reference Standard (Control 915) and was defined as 1 mg [potency] per mg.

Joint risks in a case-control study of esophageal cancer in Shanxi Province, People's Republic of China

A multifactorial analysis on the etiology of esophageal cancer was conducted based on a case-control study conducted in Shanxi. The study analyzed the data of 326 cases and 396 controls. The joint risks of two factors were calculated from dichotomous distributions. Three models of factor combinations were assessed: (1) two risk-enhancing factors, (2) two risk-reducing factors, and (3) a risk-enhancing and a risk-reducing factor. The observed joint risks were in the neighborhood of the multiplicative products of single acting risks of individual factors. This was a uniform pattern across three models.

Esophageal cancer in Shanxi Province, People's Republic of China: a case-control study in high and moderate risk areas

Dietary, smoking, and drinking habits, as well as sociopsychological factors and familial history, were investigated in a case-control study on the etiology of esophageal cancer (EC) in two areas of Shanxi (Yangcheng and Linfen), north central China. Data were analyzed from 326 cases and 396 controls. We identified several factors associated with high or low risk; some were common across the areas and others were area-specific. Consumption of millet gruel was associated positively with EC, in a dose-response relationship. An increase in EC risk was seen for consumption of millet soup with noodles, and also with certain sociopsychological factors, in both areas. A large increase in risk was found with consumption of boiled vegetables in Linfen, with a dose-response relationship. EC risk tended to become greater with the increasing intake of moldy foods and of pickled vegetable juice. A positive association between EC risk and family history of EC was observed only in Yangcheng. Soybean consumption was found to be associated with reduced risk. Dental hygiene (brushing teeth) was associated with reduced risk in Linfen. There was a suggestion of increased risk associated with heavy tobacco smoking, but it was not significant in either area. Alcohol consumption had a marginally significant association with risk in the high risk area, but not in Linfen.

[Immunohistochemical Study of 3-methylcholanthrene inducible cytochrome P-450 in the stomach and liver--a guide of postoperative chemotherapy in gastric cancer]

Immunohistochemical determination of 3-methylcholanthrene (MC) inducible cytochrome P-450 (MC-P-450) was investigated in rat and human tissue, and its clinical availability was discussed. Induced by MC, MC-P-450 in rat liver and stomach was well stained immunohistochemically, showing clear contrast against control without induction. The staining intensity in the tissue was correlated with the amount of tissue MC-P-450 which was determined previously by electrophoretical and biochemical technics. By the same immunohistochemical method MC-P-450 in human liver and stomach was also detectable. The staining grade of MC-P-450 in human liver and stomach was different from each person. However, its intensities in liver and stomach in the same individual showed clear correlation with p less than 0.02. Since MC-P-450 in liver plays a major role in drug metabolism, the proof of correlation between staining degree of the resected stomach and hepatic tissue would provide useful clue in gastric cancer for postoperative administration of masked compounds activated by MC-P-450.

Nuclear but not mitochondrial genome involvement in 3-methylcholanthrene-induced expression of tumorigenicity in mouse somatic cells

The involvement of heritable modifications of mitochondrial DNA (mtDNA) in chemical carcinogenesis was examined by studies on the effects on tumorigenicity of interchange of mtDNA between 3-methylcholanthrene (MCA)-induced mouse tumor cells and nontumorigenic mouse cells by the cytoplast-to-cell fusion technique. The difference in propagating abilities of two types of mouse mtDNA, type 1 mtDNA of B10mtJ strain and type 2 mtDNA of C57BL/10 strain, was applied successfully for complete replacement of the host cell mtDNA by cytoplasmically transmitted mtDNA. Tumorigenicity was assayed in nude mice by inoculating 5 x 10(6) cells s.c. into the backs of the mice. The results showed that tumorigenicity was not induced in nontumorigenic cells by replacement of their mtDNA by that from MCA-induced tumor cells. Moreover, the tumorigenicity of MCA-induced tumor cells was still expressed when their mtDNA was replaced by that from normal cells with a limited life span. These observations suggest that, even if MCA treatment causes heritable modifications of mtDNA, modified mtDNA cannot induce chemical carcinogenesis and that modifications of nuclear DNA alone are sufficient for the expression of tumorigenicity.

[Clinical study on the effect of chemotherapy in the treatment of pancreatic cancer]

The effect of chemotherapy in the treatment of pancreatic cancer was evaluated on the basis of prognosis in 299 patients treated at the Kobe University Hospital and the Interhospital Cooperative Study Group for Multidisciplinary Approaches to Treatment of Pancreatic and Biliary Cancer. One hundred forty-three patients with pancreatic cancer were treated with a number of chemotherapeutic agents, while ninety-eight patients did not receive any chemotherapy. There were no significant differences in clinical characteristics between the two groups. The treated patients had a median survival time of 6 months and a one-year cumulative survival rate of 25.3%. These were significantly different compared with figures of 3 months and 9.5% for non-treated control patients. A chemotherapy regimen consisting of fluoropyrimidines was also confirmed to be effective. These results suggest that the chemotherapeutic approach appears quite promising and is effective for the treatment of pancreatic cancer.

Hybrid origin of Japanese mice "Mus musculus molossinus": evidence from restriction analysis of mitochondrial DNA

The Japanese mouse, Mus musculus molossinus, has long been considered an independent subspecies of the house mouse. A survey of restriction-site haplotypes of mitochondrial DNA (mtDNA) showed that Japanese mice have two main maternal lineages. The most common haplotype is closely related to the mtDNA of the European subspecies M. m. musculus. The other common haplotype and two minor ones are closely related to each other and to the mtDNA of an Asiatic subspecies, M. m. castaneus. Two other rare variants are probably the result of recent contamination by European M. m. domesticus. The musculus type of mtDNA is found in the southern two-thirds of Japan, whereas the common castaneus type is found in the northern third and the minor variants are found sporadically throughout Japan. The castaneus mtDNA lineage had a few minor variants, whereas the musculus lineage was completely monomorphic. By contrast, the native population of M. m. castaneus and the Chinese and Korean musculus populations were highly polymorphic. These results suggest that M. m. molossinus is a hybrid between ancestral colonies, possibly very small, of M. m. musculus and M. m. castaneus, rather than an independent subspecies.

Mitochondrial genomes in intraspecies mammalian cell hybrids display codominant or dominant/recessive behavior

A unique type of nonstochastic mitochondrial DNA (mtDNA) segregation was found in mammalian cells. In human cell hybrids isolated from the fusion of HeLa cells with 23, GM639, A549, or 293 cells, HeLa mtDNA was always lost from the hybrids, whereas both parental mtDNAs were maintained in hybrids of HeLa X 143BTK-. Similar phenomena were observed in mouse cell hybrids isolated by the fusion of cells with different mtDNA types. Types 1, 2, and 3, can be distinguished from each other by restriction fragment-length polymorphisms. The mouse cell hybrids between cells with type 1 and type 2 mtDNA always lost type 2 mtDNA, whereas the hybrids between cells with type 2 and type 3 mtDNA retained both types stably. These observations suggest that either a codominant or a dominant/recessive relationship may be present in intraspecies mitochondrial genomes of human and mouse cells. When the mitochondrial genomes in cell hybrids are codominant, stochastic segregation occurs while nonstochastic segregation occurs when they are in the dominant/recessive relationship. These concepts may help elucidate organelle heredity in animals.

[The role of cytochrome P-450 in chemical carcinogenesis--its application to human cancer epidemiology]

Most chemical carcinogens require metabolic activation before they exert their deleterious effects on an organism. This overview shows the evidence that most chemical carcinogens are metabolically activated by specific P-450 isozymes and the induction of these enzymes plays an important role in chemical carcinogenesis. On the other hand, there is circumstantial evidence from a large number of animal experiments implicating that human susceptibility to environmental cancer may be affected by genetic predisposition for drug metabolism. On the basis of these findings, several problems in application to human cancer epidemiology were pointed out.

Maternal contamination of some NZB sublines and genetic profiles of NZ-strains

Six sublines of NZB mice bred in Japan were collected and their mitochondrial DNA (mtDNA) was examined by restriction analysis. The phenotypes of at least three of these sublines (NZB/Nrs, NZB/Nga and NZB/KlJms) differed from a standard one (NZB/BlWehi). Since mtDNA is inherited maternally, all sublines of a single inbred strain should share the same mtDNA phenotype. Therefore, b-type of mtDNA should be observed in all NZB sublines. Nevertheless, the above-mentioned sublines showed d-type mtDNA. These results suggested a genetic contamination of these sublines. This was confirmed by the finding that six aberrant alleles were detected also in their nuclear genomes using biochemical markers. For elucidation of the cause of contamination, we characterized the genetic profiles of four standard NZ-strains, NZB/BlWehi NZO/BlWehi, NZC/BlWehi and NZX/BlWehi, and of common inbred strains with black coat color, C57BL/6J, C57BL/10Sn, C57BL/Ks, C58/J and AU/SsJ. We found that five of the six aberrant alleles most strongly corresponded with those of C57BL/Ks. These results suggest that this contamination was ascribable to cross of NZB mice with a certain C56BL strain. We also deduced that NAB/BlPt and NZB/Füll also probably were contaminated strains, suggesting that this contamination was not restricted to Japan.

Structure and drug inducibility of the human cytochrome P-450c gene

A human genomic clone (lambda hP-450mc-1), highly homologous to the rat cytochrome P-450c gene, was isolated and analyzed for the complete nucleotide sequence. The gene structure coincides with that of a recently reported human gene isolated from genomic DNA of a human breast carcinoma cell line, MCF-7 [Jaiswal, A.K., Gonzalez, F.J. & Nebert, D.W. (1985) Nucleic Acids Res. 13, 4503-4520] with notable exceptions in the first intron: a 320-base-pair fragment is inserted and a 650-base-pair fragment is deleted in the gene examined in the present study. The 320-base-pair insert appears to contain a moderately repetitive sequence (approx. 140 copies) in the human genome. The 650-base-pair fragment, present in intron 1 of the reported sequence, is dislocated in the lambda hP-450mc-1 to about 10(4) base pairs upstream from the putative transcription initiation site. The results of Southern blot analysis using human total DNA were compatible with the gene structure of lambda hP-450mc-1. A fusion gene, which was constructed by ligating the 5' flanking region of the gene to the structural gene for prokaryotic chloramphenicol acetyltransferase (CAT), inducibly expressed the CAT activity in mouse Hepa-1 cells in response to administered methylcholanthrene, indicating that the isolated human gene is indeed of methylcholanthrene inducibility.

Sequence search on a supercomputer

A set of programs was developed for searching nucleic acid and protein sequence data bases for sequences similar to a given sequence. The programs, written in FORTRAN 77, were optimized for vector processing on a Hitachi S810-20 supercomputer. A search of a 500-residue protein sequence against the entire PIR data base Ver. 1.0 (1) (0.5 M residues) is carried out in a CPU time of 45 sec. About 4 min is required for an exhaustive search of a 1500-base nucleotide sequence against all mammalian sequences (1.2M bases) in Genbank Ver. 29.0. The CPU time is reduced to about a quarter with a faster version.

Absence of extensive recombination between inter- and intraspecies mitochondrial DNA in mammalian cells

Recombination of mammalian mitochondrial DNA (mtDNA) was examined using mouse X rat somatic cell hybrid clones and rat cybrid clones. The mouse X rat hybrids were isolated by fusion of chloramphenicol-sensitive (CAPs) mouse and CAP-resistant (CAPr) rat cells. The rat cybrids were isolated by fusion of rat cells with type B mtDNA and enucleated cells with type A mtDNA. Genetic and physical analyses showed that the mtDNAs of the hybrids and cybrids were simple mixtures of the two parental mtDNAs except in the following two cases: One was subclone H2-9 of mouse X rat hybrids, which was CAPr even though mtDNA from the CAPs mouse parent was predominantly retained. The other was rat cybrid subclones, Y12-24 and -61, which showed specific loss of one Hinf I fragment of type B mtDNA, B10. These observations suggest that, in contrast to the case with plant mtDNA, recombination of mammalian mtDNA occurs rarely, if at all.

Possible steroid binding site common to adrenal cytochrome P-450scc and prostatic steroid binding protein

By searching the entire PIR-protein-sequence data base, we have found that a dodecapeptide sequence in bovine adrenal cytochrome P-450scc is closely related to that in rat prostatic steroid binding protein. The two proteins belong to unrelated protein families, but both have steroids as substrates or ligands. Thus, the dodecapeptides may be important for substrate/ligand recognition in the individual proteins.

Isolation and characterization of intraspecific cybrids. Effect of mitochondrial DNA on their cellular properties

Cybrid clones were obtained by fusing whole cells of rat glioma C6BU-1, resistant to 5-bromodeoxyuridine (BrdU), with cytoplasts of embryonic rat 3Y1CAP cells, resistant to chloramphenicol (CAP), in selective medium with BrdU and CAP. The clones resistant to BrdU and CAP were confirmed to be cybrids by chromosome and mtDNA analyses. More than half the mtDNA of all the cybrid clones was from the 3Y1CAP cells. After cultivation of a cybrid clone Y22 for 3 months in the absence of CAP, subclones were isolated. One subclone Y22-22 contained predominantly mitochondrial DNA (mtDNA) from the 3Y1CAP cells. Using this subclone, the effects of the mitochondrial genome on cellular properties were examined. The growth patterns, expression of glioma-specific beta-adrenergic receptor, and composition of the major proteins of C6BU-1 cells were not affected by transmitted mtDNA from the 3Y1CAP cells. This procedure for isolating cells containing predominantly foreign mtDNA will be useful in studies on the interaction between genomes of the mitochondria and nucleus.

Effect of mitochondrial DNA transmitted cytoplasmically from nontumorigenic to tumorigenic rat cells on the phenotypic expression of tumorigenicity

The effect of mitochondrial DNA (mtDNA) on the phenotypic expression of tumorigenicity was examined by its cytoplasmic transmission from nontumorigenic cells to tumorigenic cells. Enucleated cells of the rat embryonic cell line 3Y1CAP, which are nontumorigenic and resistant to chloramphenicol, were fused with whole cells of the rat glioma C6BU-1 line, which are tumorigenic and resistant to 5-bromodeoxyuridine, and the cybrid colonies growing in selective medium with 5-bromodeoxyuridine (30 micrograms/ml) and chloramphenicol (50 micrograms/ml) were isolated clonally. Cytoplasmic transmission of 3Y1CAP mtDNA to C6BU-1 cells was confirmed by quantitative analysis of their mtDNA with restriction endonuclease. Subclones containing various amounts of mtDNA from 3Y1CAP cells were isolated from one cybrid clone, Y22, and their tumorigenicities were examined by inoculating 2 X 10(6) cells s.c. into nude mice. The tumorigenicities of these cybrid cubclones were almost identical to that of the nuclear donor C6BU-1 cells with respect to the tumor incidence (number of animals bearing tumors per number of animals inoculated), latent period, and growth rates of tumors. Moreover, analysis of chromosomes and mtDNAs of the cells recovered from the tumors obtained showed that the tumors were derived from the cells inoculated and that no selective overgrowth of segregants that had lost mtDNA from 3Y1CAP cells occurred in the nude mice. These observations suggest that expression of tumorigenicity of C6BU-1 cells was not suppressed by cytoplasmic transmission of nontumorigenic 3Y1CAP mtDNA.

Titration of mRNAs for cytochrome P-450c and P-450d under drug-inductive conditions in rat livers by their specific probes of cloned DNAs

By sequence analysis of the cloned cDNA or genomic DNA, we have recently deduced the complete primary structures of two forms of 3-methylcholanthrene-inducible cytochromes P-450 (P-450c and P-450d). Comparing these sequences, we identified two highly conserved regions, amino acid numbers from 35 to 200 and from 340 to 470. The nucleotide sequences corresponding to these homologous regions are also well conserved, whereas other regions have undergone considerable sequence divergence. In RNA blot analysis with unfractionated mRNA isolated from 3-methylcholanthrene-treated rat livers, Probe A (specific to P-450c sequence) hybridized with mRNA around 23 S, while Probe B (specific to P-450d sequence) hybridized with mRNA around 18 S. When common sequence between P-450c and P-450d was used as the probes (Probe C or D), two bands were clearly observed around 23 and 18 S mRNAs. With the common DNA sequence between P-450c and P-450d as a probe (93.7% homology), we studied the induction of specific mRNA for P-450c and P-450d by a single dose of several chemical compounds to rats. 3-Methylcholanthrene increased both P-450c and P-450d mRNA levels by 50 and 10 times above the control at 17 h after the administration, respectively. Despite the lower induction rates, the P-450d mRNA level was constantly higher than or at least similar to that of P-450c mRNA. beta-Naphthoflavone and Kaneclor KC 500 showed similar induction ability to 3-methylcholanthrene. On the other hand, isosafrole induced P-450d mRNA to a much greater extent than P-450c mRNA.

Coding nucleotide sequence of 3-methylcholanthrene-inducible cytochrome P-450d cDNA from rat liver

We determined the coding nucleotide sequence of the mRNA for a 3-methylcholanthrene-inducible cytochrome P-450, P-450d, of rat liver by sequence analysis of cloned cDNAs. The predicted amino acid sequence of the cytochrome is composed of 513 amino acids, and its NH2-terminal sequence of 30 amino acids completely coincides with that reported from analysis of the purified cytochrome P-450d. The amino acid composition of the deduced sequence also agrees well with that determined from the purified protein. Computer-aided analysis was carried out to compare the complete primary structures of five species of cytochrome P-450, two molecular species of phenobarbital-inducible rat liver cytochrome P-450 (P-450b and P-450e), phenobarbital-inducible rabbit liver cytochrome P-450LM2, 3-methylcholanthrene-inducible rat liver cytochrome P-450d, and camphor-hydroxylating P-450 of Pseudomonas putida (P-450CAM). It is concluded therefrom that the time of divergence between cytochrome P-450b (P-450e) and P-450d is much earlier than that of branching between phenobarbital-inducible cytochromes P-450 of rat and rabbit. One highly conserved cysteine-containing region that is close to the COOH terminus is found in all of these cytochrome P-450 sequences, indicating that the heme-binding site is the cysteine residue in this region.

Molecular cloning of a complementary DNA to 3-methylcholanthrene-inducible cytochrome P-450 mRNA from rat liver

Poly(A)+ RNA was isolated from membrane-bound polysomes of the livers of 3-methylcholanthrene (MC)-treated rats, and was partially purified by sucrose density gradient centrifugation. The mRNA was translated in an in vitro rabbit reticulocyte lysate system, and assayed for the synthesis of MC-inducible forms of cytochrome P-450 (cytochrome P-450MC) using anti-cytochrome P-450c antibody which reacted with two types of cytochrome P-450MC, P-450c, and P-450d. The mRNA activity for cytochrome P-450MC was located at around 18S, accounting for approximately 5% of total mRNA activity. The double-stranded complementary DNA which had been synthesized from the partially purified mRNA by avian myeloblastosis virus reverse transcriptase and DNA polymerase I (Klenow enzyme) was cloned in Escherichia coli X1776, using plasmid pBR322 as a cloning vector. After differential colony hybridization using [32P]cDNA's synthesized from mRNA preparation of MC-treated or untreated rat liver as a probe, a clone (3-9-1) carrying cytochrome P-450MC cDNA sequence was identified by a positive hybridization-translation assay. The specific mRNA hybridized with plasmid 3-9-1 DNA showed an enriched synthesis of a protein with apparent molecular weight of 56,000 daltons, which was immunoprecipitable with anti-P-450c antibody. In RNA blot analysis with MC-, polychlorinated biphenyls (PCB)-, and phenobarbital (PB)-induced mRNA as well as uninduced mRNA, a longer cDNA (P-34) which had been isolated by hybridization with the insertion of clone 3-9-1, and the previously isolated PB-inducible cytochrome P-450b cDNA (Fujii-Kuriyama et al. (1982) Proc. Natl. Acad. Sci. U.S. 79, 2793-2797) hybridized with mRNA preparations in an inducer-specific manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of mitochondrial DNA composition on the cellular properties of interspecific hybrid cells

Four subclones with single species of mitochondria and three subclones with both parental mitochondria were isolated from a mouse-rat hybrid cell line H2. The effects of the coexistence of different species of mitochondria on cellular properties were examined in these clones. Growth properties were studied by comparing the plating efficiencies and doubling times. The numbers of growing colonies and the doubling times of all the subclones were found to be almost the same, indicating that these growth properties were not affected by the presence of both mouse and rat mitochondria within the cells. The correlation between the expression of chloramphenicol (CAP)-resistance and the relative contents of mtDNA of CAP-resistant (CAPr) rat and CAP-sensitive (CAPs) mouse parent cells in the subclones were also examined. The expression of CAP resistance was measured as the relative plating efficiency. Subclones with a high content of mtDNA from CAPr rat parent cells showed high relative plating efficiency.

Immunochemical study on the contributions of two molecular species of microsomal cytochrome P-450 to the metabolism of benzo(a)pyrene by rat liver microsomes

The roles of two species of cytochrome P-450, the major cytochrome P-450 components of liver microsomes of phenobarbital-treated rats (PB-P-450) and 3-methylcholanthrene-treated rats (MC-P-448), were studied in the metabolism of benzo(a)pyrene in rat liver microsomes in vitro. Benzo(a)pyrene was incubated with polychlorinated biphenyl-treated rat liver microsomes, in which PB-P-450 and MC-P-448 constituted about 45 and 24% of the total cytochrome P-450, respectively. Then the metabolites were separated into those soluble in ethyl acetate and in water, and those covalently bound to protein. Using high-pressure liquid chromatography, the ethyl acetate-soluble metabolites were separated into three major groups, phenols, quinones, and dihydrodiols, including peaks of three unknown materials. Addition of anti-MC-P-448 immunoglobulin to the reaction mixture completely inhibited the formation of all ethyl acetate-soluble metabolites. In contrast, anti-PB-P-450 immunoglobulin did not inhibit the formations of 4,5-dihydro-4,5-dihydroxybenzo(a)pyrene and 3-hydroxybenzo(a)pyrene; partially inhibited the formations of 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene, 9, 10-dihydro-9, 10-dihydroxybenzo(a)pyrene, and the three unknown materials; and caused 30 to 40% enhancement of the formations of 9-hydroxy-benzo(a)pyrene and benzo(a)pyrene-3,6-dione and 80% enhancement of that of benzo(a)pyrene-1,6-dione. Antibody against MC-P-448, but not against PB-P-450, also caused 75% inhibition of the formation of water-soluble metabolites and 85% inhibition of formation of benzo(a)pyrene metabolites covalently bound to protein. These results show that MC-P-448 is important in the metabolism of benzo(a)pyrene.

Two distinct types of mitochondrial DNA segregation in mouse-rat hybrid cells. Stochastic segregation and chromosome-dependent segregation

Two distinct patterns of mitochondrial DNA (mtDNA) segregation were found in different mouse-rat hybrid cell lines. On mouse-rat hybrid cell line, H2, retained complete sets of chromosomes and mtDNAs of both mouse and rat. Even after cultivation for about one year after cloning, the H2 cell population still retained both parental mtDNAs. However, when mtDNAs of H2 subclones were examined, it was found that some individual cells in the H2 cell population contained only mouse or only rat mtDNA, although they still retained complete sets of both kinds of parental chromosomes. This type of mtDNA segregation, named stochastic segregation, is bidirectional and may be caused by the repetition of random sharing of mouse and rat mtDNAs with daughter cells. This segregation occurred spontaneously during long-term cultivation. The second type of mtDNA segregation, named chromosome-dependent segregation, was found in the other mouse-rat hybrid cell lines that segregated either mouse or rat chromosomes. In these hybrid cells, chromosomes and mtDNA of the same species co-segregated. This second type of segregation is unidirectional. The types of mtDNA segregation appear to depend on the stability of the parental chromosomes in the hybrid cells. When both mouse and rat chromosomes retain stably, mtDNA shows stochastic segregation. On the contrary, when either species of chromosomes is segregated from the cells, mtDNA shows chromosome-dependent segregation.

Structural characteristics of cytochrome P-450. Possible location of the heme-binding cysteine in determined amino-acid sequences

Computer-aided analyses were made of the complete amino-acid sequences of two P-450 species, the phenobarbital-inducible major P-450 of rat liver microsomes (P-450PB) and camphor-hydroxylating P-450 of Pseudomonas putida (P-450cam). Statistically significant homology was recognized between the two P-450 sequences, but these sequences were not related to those of other groups of hemoproteins, such as hemoglobins, peroxidases, and cytochrome c's and b's. Two highly homologous regions, HR1 and HR2, and two other weakly homologous regions were found on optimally matched alignment of the P-450 sequences. The secondary structures of the two P-450's predicted by current prediction methods bear strong resemblance at these homologous regions. Both HR1 and HR2 contain a cysteine residue near the center of the homologous regions, and they are the only regions that show significant homology among all 48 combinations of local sequences around the cysteine residues (six on P-450PB and eight on P-450cam). HR1 is located in the N-proximal half of the molecule, is rich in hydrophilic residues, and is predicted to be helical. On the other hand, HR2 is close to the C-terminus, has intermediate hydrophobicity, and may take a complex secondary structure of a turn-sheet-helix. The amino-acid sequences around the HR1 and HR2 regions are also well conserved in another P-450 species, rabbit P-450LM2.

[Influence of the surgical stress on graft-versus-host reaction in mice--the suppressor activity to GVH reaction induced by the surgical operation]

The influences of surgical stress on the local graft-versus-host reaction (GvHR) in F1 mice were studied. Skin incision to the F1 mice inflicted to 1 day prior to injection of parental spleen cells produced impairment of popliteal lymph node enlargement, however, this effect was not observed when GvHR was induced on the day 3 and 5 after operation. Spleen cells from hind limb amputated F1 mice exhibited suppressor activity on local GvH reaction when injected into naive syngenic F1 mice together. This suppressor activity was markedly detected 3 and 24 hrs after operation, then gradually reduced and completely disappeared on the day 7. These suppressor activity completely disappeared by the treatment with anti-Thy 1.2. antibody and complement. These results showed that GvH reaction was suppressed by the surgical stress, and this suppression was due to suppressor T lymphocytes in the spleen.

Origins of laboratory mice deduced from restriction patterns of mitochondrial DNA

To determine the origins of laboratory mice, the restriction patterns of mitochondrial DNAs (mtDNAs) from various strains were compared with those of relevant subspecies and/or races of Mus musculus. In most strains and substrains of laboratory mice examined (50/55), the cleavage patterns were identical to those of the European subspecies M. m. domesticus. Those that varied include two sublines of NZB, the strain NZC, and the Japanese strain RR. The NZB and NZC patterns were identical to that of the European subspecies M. m. brevirostris, which itself has restriction patterns similar to M. m. domesticus. On the other hand, the RR pattern was identical to M. m. molossinus-like mice trapped in Western China and slightly different from Japanese M. m. molossinus. These findings suggest that the strains NZB and NZC stemmed from a European founder stock which differed from the ancestral stocks of other laboratory strains and that the ancestral mice of the RR strain had been transported from China to Japan. Therefore, most laboratory strains of mice are derived from the European subspecies M. m. domesticus while M. m. brevirostris and M. m. molossinus have made minor contributions. M. m. musculus does not appear to have made any contribution.

Specific suppression of the local GVH reaction by F1 spleen cells

The local graft-versus-host (GvH) reaction in (C57BL/6 X BALB/c) F1 hybrid mice, assayed by popliteal lymph node enlargement, was specifically depressed by an injection of parental lymphocytes mixed with spleen cells from F1 mice pretreated with the same parental lymphocytes. Suppressor activity of CBF1 spleen cells was obtained 7 days after inoculation of parental lymphocytes, and peaked on day 10. The suppressive activity was induced by only spleen cells from CBF1 which was inoculated Balb/c lymphocytes, but not C57BL/6 lymphocytes. The lymphocyte subpopulation responsible for the suppressive activity was noticed in T cell population.

Mitochondrial DNA analysis of mouse-rat hybrid cells: effect of chloramphenicol selection on the relative amounts of parental mitochondrial DNAs

Several mouse-rat somatic hybrid cell lines were isolated by fusing chloramphenicol-resistant (CAPr) and CAP-sensitive (CAPs) parent cells, and propagation of the parent mitochondrial DNA (mtDNA) species in the hybrid cells was studied. The restriction endonucleases EcoRI, HpaII, and HaeIII were used for identification of mtDNA species. Both mouse and rat mtDNAs were propagated in all the hybrid cells examined and maintained during long-term cultivation and repeated cell division. Moreover, in CAPr mouse-rat hybrid cells, selection and successive cultivation in the presence of CAP did not increase the relative amount of mtDNA species of CAPr parent cell origin, and when CAP was removed from the culture medium, mtDNA species of CAPr parent cell origin did not decrease appreciably. The amount of mouse mtDNAs was consistently 1-4 times that of rat mtDNAs inthe mouse-rat hybrid cells regardless of the species of parent cells from which the CAP resistance was derived. Thus mouse-rat hybrid cells have a stable mtDNA population in which the amount of mouse mtDNAs is larger than that of rat mtDNAs without any influence of CAP selection.

Polymorphisms of mitochondrial DNAs in Norway rats (Rattus norvegicus): cleavage site variations and length polymorphism of restriction fragments

Extensive polymorphism was found in mitochondrial DNAs (mtDNAs) of Norway rats (Rattus norvegicus). The restriction endonuclease cleavage patterns of mtDNAs of laboratory rats, wild rats, tumor cells, and culture cells were compared. The polymorphism is defined by two criteria; one is cleavage site variation and the other is length polymorphism of restriction fragments. The cleavage site variation may be caused by point mutation, and the length polymorphism by sequence deletions or insertions. At least five types, types A-E, were identified by cleavage site variations, and two groups, a and b, were identified by length polymorphism of one HpaII fragment, Hpa5. All types except type C belonged to either group-a or group-b, whereas both groups were found in type C. Differentiation of polymorphic Norway rat mtDNA types and the experimental use of the polymorphism are discussed.

Evolutionary relationships among five subspecies of Mus musculus based on restriction enzyme cleavage patterns of mitochondrial DNA

The intra- and intersubspecific genetic distances between five subspecies of Mus musculus were estimated from restriction enzyme cleavage patterns of maps of mitochondrial DNA (mtDNA). The European subspecies, M. m. domesticus and Asian subspecies, M. m. bactrianus, M. m. castaneus, M. m. molossinus and M. m. urbanus were examined. For each subspecies, except M. m. urbanus, at least two local races from widely separated localities were examined. Intrasubspecific heterogeneity was found in the mtDNA cleavage patterns of M. m. bactrianus and M. m. castaneus. M. m. molossinus and M. m. domesticus, however, revealed no intrasubspecific heterogeneity. Four of the subspecies had distinct cleavage patterns. The fifth, M. m. urbanus, had cleavage patterns identical to those of M. m. castaneus with several enzymes. Estimates of genetic distances between the various races and subspecies were obtained by comparing cleavage maps of the mtDNAs with various restriction enzymes. Nucleotide sequence divergences of mtDNA between local races were estimated to be less than 0.4% in M. m. bactrianus and less than 0.3% in M. m. castaneus. The times of divergence of both subspecies were calculated to be 0.1--0.2 x 10(6) years. These values suggest that the intrasubspecific divergence began some 0.1--0.2 x 10(6) years ago. On the other hand, nucleotide sequence divergences between European subspecies M. m. domesticus and Asian subspecies M. m. bactrianus and M. m. castaneus were 7.1% ane 5.8%, respectively. The times of divergence were calculated to be 2.1--2.6 x 10(6) years. Further, the nucleotide sequence divergence and time of divergence between M. m. molossinus and the other two Asian subspecies were comparable to those between M. m. molossinus and M. m. domesticus (about 3% and 1 x 10(6) years, respectively). These results suggest that M. m. molossinus is situated in a unique evolutionary position among Asian subspecies.