Direct cloning by covalent attachment of probe DNA to target DNA

A novel cloning procedure which makes use of covalent attachment of probe DNA to specific target DNA is reported. We show that specific gene fragments found in complex genomes such as the human genome can be cloned directly from a pool of genomic DNA with very high efficiency. This direct cloning method totally eliminates certain steps in current cloning procedures such as construction of DNA libraries and colony (plaque) hybridization. The resulting process has made cloning methods simpler and more time efficient, while achieving high cloning efficiency due to the stable nature of the probe-target DNA complex through covalent bonding. Most importantly, since clones are directly obtained from a pool of genomic DNA, the isolated clones are considered to be faithful copies of the original genes. This has apparently solved the problem of isolating clones with misincorporated bases or chimeric DNA, both of which are often encountered in cloning processes using PCR or other methods involving in vitro DNA synthesis.

Anti-DNA IgA autoantibodies are spontaneously generated in mouse Peyer's patches

IgA antibodies in the mucosal immune system are produced specifically to environmental antigens such as virus and bacteria, and possibly to some food components, which will provide a potential luminal antigen, DNA. To study the immune response to DNA in the gut, we established B-cell hybridomas producing IgA monoclonal antibodies (mAb) from Peyer's patches (PP) of non-immunized, non-autoimmune, specific pathogen-free BALB/c mice, and examined their specificity by enzyme-linked immunosorbent assay (ELISA). Three mAb out of 18 bound strongly to self, bacterial and synthetic DNA, with Kd of about 10-7 m. One of the three mAb also reacted with the histone component and another reacted with some mouse food component. The VH genes of these three mAb have not previously been reported to have anti-DNA specificity, and carry putative somatically mutated sites favouring DNA binding in CDR. The features resemble those of anti-DNA antibodies found in human and murine models of systemic lupus erythmatosus (SLE), and are indicative of an antigen-driven selection process. Our findings suggest that even in normal healthy animals, anti-DNA antibodies of IgA isotype can be produced in certain peripheral environments such as in PP by spontaneous antigenic stimulation.

The effectiveness of O2 administration for transient ischemic attacks in moyamoya disease in children

Moyamoya disease is a cerebrovascular obstructive disease of unknown etiology. The rebuild-up phenomenon, slowing of waves on electroencephalogram (EEG) seen after cessation of hyperventilation (HV), is one of the characteristic phenomena of the disease and is thought to be related to a development of its symptoms. Therefore, we investigated the mechanism involved in the rebuild-up phenomenon to clarify the mechanism of development of transient ischemic attack (TIA) in moyamoya disease. Ten patients with moyamoya disease were studied; they ranged in age from 7 to 17 years. The power spectra of the EEGs in the occipital region were obtained with a Berg Fourier EEG analyzer for quantitative analysis. Arterial blood gas change (pH, PaO2, PaCO2), respiratory pattern (abdominal and nasal), tidal volume and respiratory rate were analyzed simultaneously every 30 s-1 min before, during, and after HV. The slow wave power spectrum (rebuild-up) increased and symptoms of TIA developed as a result of the sharp decrease in PaO2 (PaO2 60.5 +/- 15.4 mmHg) after cessation of HV. Based on the fact that hypoxemia was playing a main role, 100% oxygen was administered at a rate of 0.5 l/min in 4 cases where the rebuild-up phenomenon was clear. The EEG power spectra and arterial blood gas were analyzed during rebuild-up with and without O2 administration. The effectiveness of O2 administration at the beginning of rebuild-up as measure to prevent the symptoms was checked by a recovery rate of slow wave power percentage, a recovery time of slow wave power percent and by clinical observation. The recovery rates were 11.8 +/- 4.2%/min and 5.5 +/- 4.0%/min with and without O2 inhalation, respectively (P < 0.001). Recovery times of slow wave power percentage were 4.3 +/- 1.8 min and 8.1 +/- 1.2 min with and without O2 inhalation, respectively (P < 0.01). Thus, oxygen administration soon after the cessation of HV was shown to be effective in eliminating the rebuild-up phenomenon and hence in abolishing its symptoms.

A novel regulatory sequence affecting the constitutive expression of tissue plasminogen activator (tPA) gene in human melanoma (Bowes) cells

In order to identify a possible enhancer-like regulatory sequence for the human tissue plasminogen activator (tPA) gene, various DNA segments in the 5'-flanking region were ligated to the chloramphenicol acetyltransferase (CAT) reporter gene driven by the tPA gene promoter, and their CAT enhancing activities were measured following transfection to human melanoma-derived Bowes cells that highly express the gene. Major and minor activities were detected in two adjacent upstream sequences, 160 base pairs (bp) (-2288 to -2129) and 102 bp (-2390 to -2289), respectively, and the former was subjected to further analysis. The CAT enhancing activity of the 160-bp sequence was greatly affected by its position and orientation in the constructs and the sequence also functioned weakly with the SV40 promoter. Deletion of any small portion from the sequence abolished the CAT enhancing activity, suggesting that the entire sequence is required for the activity. This sequence did not show a further CAT enhancing activity in Bowes cells treated with the inducers phorbol 12 myristate 13-acetate and dexamethasone and did not function in HeLa or HT1080 cells under any conditions. Taken together, the 160-bp sequence is likely to be responsible for the constitutive and/or cell type-specific expression of the tPA gene in human cells.

Amplification of plasmid (L factor) DNA and increased production of a plasmid gene product (gamma-interferon) in mouse L cells

It has previously been reported that composite DNAs derived from L factor, a polyoma-related mammalian plasmid, can be established in several mouse cell lines after transfection. Here, we report that the copy number of a plasmid composite DNA consisting of L factor, pBR DNA, dihydrofolate reductase (dhfr) gene, and gamma-interferon (gamma-IFN) gene was increased more than 10-fold after two successive adaptations of the plasmid-bearing mouse L cells to increasing concentrations of methotrexate (MTX), an inhibitor of dhfr. The structure of the amplified L factor plasmid remained intact during prolonged cell culture, but the copy number remained to be amplified only when the selective pressure (presence of MTX in the medium) has been exerted during the culture. Cells bearing the amplified plasmid produced a higher level of gamma-IFN compared with the original clone, which was likely to be derived from the plasmid gamma-IFN gene amplified along with L factor and the dhfr gene.

A case of multiple arteriovenous malformations and diffuse venous abnormalities with facial port-wine stain

A case of left facial port-wine stain with right hemiparesis is reported. Radiologically, two arteriovenous malformations (AVM) and diffuse venous abnormalities were observed in the left hemisphere. AVM were seen in the basal ganglia. One was fed by a perforating artery from the MCA and drained into the superior petrosal sinus, and the other was fed by a perforating artery from the basilar artery and drained through the vein of Rosenthal into an extremely dilated vein of Galen. Venous abnormalities were obstruction and a decrease in the superficial cortical veins, as well as the formation of collateral veins in both the cortex and white matter. This case resembles Sturge-Weber syndrome (SWS), but there were no signs of leptomeningeal angiomatosis or venous angioma. We have been unable to find any case reports on SWS with AVM or AVM with diffuse venous abnormalities. We discuss the differences between our case and SWS.

[Drug resistant mechanisms of platinum derivatives in a human cisplatin resistant ovarian cancer cell line]

We investigated cisplatin resistant mechanisms in a cisplatin resistant ovarian cancer cell line (KFr) by means of flow cytometric analysis for damage of cisplatin to DNA base and DNA synthetic cells. Cisplatin showed cycle delay at 0.5 microgram/ml and then cycle arrest at 1 microgram/ml in G2 + M phase. KFr cells showed relatively rapid inhibition of DNA synthesis based with G-C base damage by cisplatin however, KFr cells had a capacity to repair DNA damage by cisplatin as showing cycle progression from G2 + M phase to G1-early S phase. Of the cisplatin derivatives tested which are of current clinical interest, Carboplatin and DWA 2114 R showed cross resistance to cisplatin in KFr cells.

Establishment of composite DNA derived from L factor as a plasmid in mouse embryonal carcinoma (F9) cells

We have recently reported a mammalian cell plasmid (L factor) whose structure is related to that of polyomavirus (T. Kusano, H. Uehara, H. Saito, K. Segawa, and M. Oishi, Proc. Natl. Acad. Sci. USA 84:1789-1793, 1987). When composite DNA constructed from L factor and a foreign gene was introduced into mouse embryonal carcinoma (F9) cells by transfection, the DNA was reestablished in the cells as a plasmid. The reestablished plasmid DNA in F9 cells could be rescued in Escherichia coli. The plasmid-bearing cells underwent normal in vitro differentiation in response to retinoic acid. The efficiency of plasmid establishment of the L-factor-derived DNA and transcriptional and transient replicational activities were compared with those of similar composite DNA constructed from polyomavirus and an embryonal carcinoma mutant of polyomavirus which is permissive in F9 cells. The results suggest an inverse relationship between the efficiency of the plasmid establishment and the activity of gene expression controlled by the intrinsic enhancer-promoter of the DNA.

Effect of altered plasma protein binding on pharmacokinetics and pharmacodynamics of propranolol in rats after surgery: role of alpha-1-acid glycoprotein

The pharmacokinetics and pharmacodynamics of propranolol in rats 2 days after laparotomy were compared to control animals. The apparent volumes of distribution and the systemic clearance of propranolol were decreased to about 20 to 40 and 70% of control values, respectively. The area under the blood concentration-time curve (AUC) of propranolol after p.o. administration showed a marked elevation after surgery and its availability increased about 2-fold at doses of 5.0 and 12.5 mg/kg. These changes were associated with a decreased plasma unbound fraction of propranolol after surgery. Immunological determination of alpha-1-acid glycoprotein (AGP) revealed a marked increase after laparotomy and a linear relationship was found between the plasma AGP concentration and the binding capacity of high-affinity binding site for propranolol in plasma (r = 0.961, P less than .001). AUC of p.o. administered propranolol was also correlated with plasma AGP concentration. The beta-blocking activity of propranolol assessed by the reduction in the isoproterenol-induced tachycardia was decreased in rats after laparotomy when it was evaluated in terms of the total plasma concentration of propranolol. In contrast, its activity evaluated by the unbound plasma concentration showed no difference between control and laparotomized rats, suggesting the dependence of the pharmacological activity of propranolol on its unbound level in plasma. Thus, laparotomy-induced changes in both pharmacokinetics and pharmacodynamics could be considered largely due to an increase in its binding to the increased plasma level of AGP.

Justification and implementation of an oncology pharmacist practitioner in an HMO setting

The role of an oncology pharmacist practitioner in an outpatient clinic is described. The clinic provides cancer treatment and follow-up to approximately 60 to 80 patients per day. The hospital pharmacy department, the director of the medical oncology service, and the oncology nurse specialist presented a proposal to the clinic administration for the employment of a full-time pharmacist. Previously, the clinic nursing staff prepared all chemotherapeutic agents. The oncology pharmacist now prepares between 35 to 75 chemotherapy drug doses per day. As a result, nurses are able to devote more time to direct patient care. Through the application of inventory management, clinic drug costs have been reduced. In addition, patients undergoing chemotherapy no longer have to wait for their prescriptions since the oncology pharmacist calls them to the outpatient pharmacy. A valuable service has been introduced tht not only benefits the clinic personnel, but also assures that the patients receive the highest standards of care.

Influence of acute renal failure on pharmacokinetics of phenolsulfonphthalein in rats: a comparative study in vivo and in the simultaneous perfusion system of liver and kidney

The effect of acute renal failure (ARF) on the disposition of phenolsulfonphthalein (PSP) after intravenous administration was investigated in rats. ARF was induced by the subcutaneous injection of uranyl nitrate to rats. Renal excretion of PSP decreased significantly in ARF compared to that in normal controls. On the other hand, rats with ARF showed an increased biliary excretion of PSP to compensate for reduced renal excretion of the drug. Consequently no significant change was found in total body clearance of PSP between control and ARF. The in vitro binding experiment showed that the binding fraction of PSP to ARF plasma was significantly lower than that to control plasma. In order to clarify the regulatory mechanisms of PSP excretion between liver and kidney in ARF, we developed a simultaneous perfusion system of rat liver and kidney, which could control the flow rate and the constituent of the perfusate. In this perfusion system, neither biliary excretion nor the protein binding of PSP differed significantly between control and ARF, though its renal excretion decreased in ARF in a similar manner as in vivo. These results suggest that alterations in plasma protein binding as well as renal excretory function are determinants of PSP disposition in ARF.

Increased availability of propranolol in rats with uranyl nitrate-induced acute renal failure

The effect of acute renal failure (ARF) on the pharmacokinetics of propranolol was investigated. The model of ARF was produced by the subcutaneous injection of uranyl nitrate to rats (10 mg/kg) and was used 3 d after treatment. Uranyl nitrate-treated rats showed significantly higher plasma concentrations of propranolol after oral administration and the area under the plasma concentration-time curve increased about 3-fold compared to control rats. The plasma disappearance of propranolol after intravenous administration did not differ significantly between control and ARF. The mean availability of propranolol after oral administration increased from 0.120 in control to 0.215 in ARF (p less than 0.005). Absorption of propranolol was almost complete and no significant difference was found between two groups. No changes in plasma protein binding of propranolol and hepatic blood flow were observed in ARF. On the other hand, hepatic clearance of propranolol determined by liver perfusion studies showed a significant reduction in ARF and the calculated intrinsic clearance of unbound propranolol at a dose of 6.25 mg was 26.8 +/- 2.3 ml/min in control and 16.0 +/- 2.3 ml/min in ARF (p less than 0.01). These results demonstrate that the oral availability of propranolol increased in ARF due to a reduction in the hepatic presystemic elimination as compared to healthy control rats.