Comparison of the disposition of hepatically-generated morphine-3-glucuronide and morphine-6-glucuronide in isolated perfused liver from the guinea pig

PURPOSE

Humans and guinea pigs metabolise morphine extensively, forming the isomers morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in relatively similar ratios. Both metabolites are formed in the liver, and their greater polarity relative to the parent aglycone may limit their permeability across hepatic membranes. This study compared the disposition of hepatically-generated M3G and M6G in perfused livers isolated from guinea pigs.

METHODS

Livers were perfused at 30 ml/min in a non-recirculating manner with Krebs bicarbonate buffer containing morphine (6 to 7 microM). Perfusing medium, venous perfusate and bile were collected at regular intervals and concentrations of morphine, M3G and M6G determined by reversed-phase HPLC.

RESULTS

Concentrations of morphine, M3G and M6G in perfusate and the rates of biliary excretion of M3G and M6G were consistent between 20 and 50 min of perfusion. The mean (+/-s.d.) ratio for the rate of formation of M3G relative to M6G was 3.7 +/- 1.5. A mean 33 +/- 3% of morphine extracted by the liver was recovered as summed M3G and M6G. Of the M3G and M6G formed during a single passage, 19 +/- 11% and 9 +/- 9%, respectively, was excreted into bile; the values were significantly different (P = 0.002).

CONCLUSIONS

A greater fraction of hepatically-generated M3G excreted into bile compared to that for M6G reflects differences in their relative transport across sinusoidal and canalicular membranes of hepatocytes, possibly via carrier-mediated systems.

Setting the stage for health impact assessment

Defining health impact assessment as any combination of procedures or methods by which a proposed policy or program may be judged as to the effect(s) it may have on the health of a population, we make recommendations about how to evaluate the health impact of all government-initiated policies. Such health impact cannot be assessed in the absence of a conceptual or organizing framework that provides the requisite guideposts--population health goals and targets. Health impact assessment offers an approach to ensuring that governments' program and policy initiatives align, or are congruent with, the agreed-upon health goals. It suggests that proposed national policies should be supported or resisted on the basis of their probable influence on the health of populations. In the current Canadian national policy framework, however, there are no underpinnings on which to situate such a process. The specification of consensus goals and objectives with measurable targets can provide the requisite guideposts and benchmarks for health impact assessment. Such an undertaking can set the stage and provide the necessary foundation for an effective health impact assessment process.

Reductant-independent ATP hydrolysis catalyzed by homologous nitrogenase proteins from Azotobacter vinelandii and heterologous crosses with Clostridium pasteuranium

Reductant-independent ATPase activity was initiated and studied for Azotobacter vinelandii and Clostridium pasteuranium nitrogenase proteins (Av1, Cp1 and Av2, Cp2, 1 designating the iron molybdenum protein and 2 the iron protein) and their heterologous crosses by two methods: (1) allowing dithionite to be depleted from a normal assay in the presence of substrate levels of MgATP and (2) using reduced but reductant-free nitrogenase proteins in the presence of substrate levels of MgATP. In both cases, at a 1:1 protein ratio, MgATP is converted initially to MgADP with a specific activity of 400-500 nmol MgATP hydrolyzed/min.mg Av1, but in slower steps the MgADP is converted to AMP and, after 12 h, AMP is ultimately converted to adenosine. This reactivity requires the presence of both proteins, increases with increasing Av2/Av1 ratio, and is not a result of unique redox states of either protein. For Av1-Av2, ATP hydrolysis in the absence of Mg2+ occurred at nearly the same rate as reductant-dependent MgATP hydrolysis. Reductant-independent ATPase activity also occurred for the Av1-Cp2 and Cp1-Av2 heterologous crosses and was 2-fold and 18-fold slower than the Av1-Av2 or Cp1-Cp2 combinations. In both cases further hydrolysis of MgADP to AMP and AMP to adenosine occurred. A unique nucleotide hydrolysis system is apparently operating in the complex formed between the two nitrogenase proteins in the absence of reductant. The relationship between the reductant-independent and reductant-dependent activities of nitrogenase catalysis is explored.

Metal ion binding to apo, holo, and reconstituted horse spleen ferritin

The binding of Cd2+, Zn2+, Cu2+, Ni2+, Co2+, Mn2+, and Mg2+ to apo, holo, reconstituted horse spleen ferritin (HoSF), and native holo HoSF with phosphate removed was measured by gel-exclusion chromatography. Three classes of strong binding interactions (Kd < 10(-7) M) with apo HoSF at pH 7.5 were found for the various M2+ studied: high stoichiometric binding (30-54 M2+/HoSF) for Cd2+, Zn2+, Cu2+, with two protons released per metal bound; intermediate binding (16 M2+/HoSF) for Ni2+ and Co2+, with one proton released per metal bound; and low levels of binding (2-12 M2+/HoSF) for Mn2+, Mg2+, and Fe2+, with < 0.5 protons released per metal bound. M2+ binding to apo HoSF was nearly abolished at pH 5.5, except for Fe2+ and Cu2+, which remained unaffected by pH alteration. Holo HoSF bound much higher levels of M2+, a result directly attributable to the presence of phosphate binding sites. This conclusion was confirmed by decreased binding of M2+ to HoSF reconstituted in the absence of phosphate and by native holo HoSF with phosphate chemically removed. The binding of Cd2+ to apo HoSF was 54 per HoSF, but in the presence of developing core, the amount bound decreased to about 30 Cd2+/HoSF. This result indicated that Cd2+ and developing core were competing for the same sites on the HoSF interior, suggesting that 24 of the Cd2+ were bound to the inside surface. No other M2+ studied bound to the interior of HoSF by this criterion. Several of the M2+ appeared to bind strongly to the phosphate-free mineral core surface in reconstituted HoSF.

Intraoperative ultrasonography in detection of hepatic metastases from colorectal cancer

PURPOSE

This study was designed to compare diagnostic accuracies of measuring liver enzymes, preoperative ultrasonography, surgical examination, and intraoperative ultrasonography for detection of liver metastases from colorectal cancer.

METHODS

Blind, prospective comparisons of diagnostic examinations mentioned above were performed in 295 consecutive patients with colorectal cancer. An experienced ultrasonologist performed the preoperative examinations, and results were unknown to the other experienced ultrasonologist who performed the intraoperative examinations. The latter, also was unaware of the findings by the surgeon. The presence of metastases was further assessed by ultrasonography three months postoperatively, as well as additional surgery and liver biopsy in some of the patients.

RESULTS

The sensitivity of intraoperative ultrasonography (62/64) was significantly superior to that of surgical exploration (54/64) and that of preoperative ultrasonography (45/64). The lowest sensitivity was presented by liver enzymes. Bilobar metastases were detected in 42 of 46 patients by intraoperative ultrasonography but in only 33 patients by the surgeon. Intraoperative ultrasonography demonstrated the highest specificity of all examinations.

CONCLUSIONS

Intraoperative ultrasonography reduces the number of patients with liver metastases from being subjected to superfluous or even harmful liver surgery, and it may increase the number in whom liver surgery will prolong life.

Use of iotrolan versus ethiodized poppy-seed oil in hysterosalpingography

PURPOSE

To compare use of the water-soluble, nonionic isosmolar dimer iotrolan with that of ethiodized poppy-seed oil in hysterosalpingography with regard to side effects, diagnostic quality, and postexamination conception rates.

MATERIALS AND METHODS

A prospective randomized design was used in a study of 245 patients. Questionnaires and patient records were used to acquire information. All examinations and ratings of diagnostic quality were performed by the same three investigators. Statistical calculations were performed with the chi 2 test, including the Mantel-Haenszel variant, and the Kruskal-Wallis test.

RESULTS

No substantial differences between the contrast media could be detected concerning pain during the procedure, delayed pain, or postexamination bleeding. Visualization of the uterine cavity and ampullary rugae was markedly better with use of iotrolan. The postexamination conception rate was higher with use of ethiodized poppy-seed oil (24.0%) but was not significantly different statistically (P = .44) from that seen after use of iotrolan (19.8%).

CONCLUSION

The authors believe the use of iotrolan is preferable to that of ethiodized poppy-seed oil.

Early treatment with nasal continuous positive airway pressure in very low-birth-weight infants

During 1988 and 1989, a regional cohort of 81 infants with birth weights less than 1501 g were treated with oxygen only (n = 11), early continuous positive airway pressure (CPAP) (n = 68) or mechanical ventilation from birth (n = 2). We used an easily applicable lightweight CPAP system with nasal prongs and a gas jet supplemented with ventilator treatment if necessary, but with conservative criteria for ventilator treatment with tolerance of high PCO2. A total of 65 infants (80%) survived to discharge, 61 of whom were supported solely with CPAP or oxygen. Nineteen infants (26%) developed periventricular-intraventricular haemorrhage, but only 4 survivors (6%) developed prognostically significant bleedings grade 2-4. No survivors had bronchopulmonary dysplasia. Follow-up at 12-39 months of age revealed definite disabilities in 6 (10%) and suspected disabilities in 2 of 62 long-term survivors. The results suggest that treatment by early CPAP with nasal prongs with tolerance of high PCO2 may be effective and lenient in most infants more than 25 weeks' gestation.

Incorporation of 15N from L-leucine into isoleucine by rat brain cerebral cortex slices

The fate of leucine nitrogen in the central nervous system was investigated by incubating rat cerebral cortex slices in the presence of 0.5 mM each of L-[15N]-leucine, L-isoleucine, and L-valine. Analysis of the slices and incubation media for free amino acids by gas chromatography-mass spectrometry revealed that the 15N from leucine is incorporated into isoleucine only. No 15N was detected in valine or any other amino acid. These results suggest that leucine, valine, and their corresponding aminotransferases may be compartmentalized in brain cerebral cortex.

HIV infection at outcome of pregnancy in the Paris area, France

The prevalence of HIV infection in women at end of pregnancy, irrespective of outcome, was determined in a comprehensive survey of both women and medical centres during successive 4-week periods in four areas of the Paris region, France. Blood samples were tested anonymously for antibodies to human immunodeficiency virus (HIV)-1 and HIV-2. Of the 11,593 blood samples 0.40% (95% confidence interval [CI] 0.28-0.51) were positive for HIV-1 and 0.02% (95% binomial interval [BI] 0.002-0.065) for HIV-2. Seroprevalence was higher among women with ectopic pregnancy (2%) (95% BI 0.24-7.04); the rate in women having an elective or therapeutic abortion was more than twice that in those delivering babies (0.70% vs 0.28%, p less than 0.05, relative risk 2.54, 95% CI 1.36-4.75). Studies with neonatal HIV seroprevalence as a surrogate for HIV prevalence in pregnant women would underestimate prevalence in these women.

Multiple oral administration of a ketoprofen-dextran ester prodrug in pigs: assessment of gastrointestinal bioavailability by deconvolution

Deconvolution has been applied to estimate the in vivo dissolution/release process of ketoprofen from a ketoprofen-dextran ester prodrug in pigs. The prodrug was given to three pigs at intervals of 12 hr and in seven doses corresponding to 4 mg ketoprofen/kg body weight. Frequent blood sampling was carried out at the first, third, and seventh intervals. Plasma steady-state concentrations of ketoprofen following the prodrug administration were between 2 and 4 micrograms/ml. The reference consisted of a single p.o. dose of parent ketoprofen (4 mg/kg body weight). For each pig the response following the multiple dosing was deconvolved with the reference response using an algebraic deconvolution procedure adopted from the literature. The obtained cumulated in vivo dissolution/release profiles revealed similar release rates for the three pigs and similar extents of release (59, 70, and 65%). The mean in vivo dissolution/release times (MDT) were calculated to be 5.4, 6.1, and 5.7 hr, respectively. In conclusion, following administration of the dextran prodrug the plasma concentration curves and the dissolution/release profiles are uniform, with small interindividual variations.

Translocation (14; 18) and (8; 22) in three patients with acute leukemia/lymphoma following centrocytic/centroblastic non-Hodgkin's lymphoma

Three patients with centrocytic/centroblastic lymphoma developed a rapidly fatal leukemic transformation of the disease after a transient remission. At the time of transformation, cytogenetic analysis revealed in all patients abnormal karyotypes with coexistence of t (14; 18) and t (8; 22). Molecular analysis in one patient showed rearrangement of the BCL 2 oncogene and c-myc m-RNA expression. These findings imply that translocation t (14; 18) was present during the first phase of the disease and that acquisition of translocation t (8; 22) was accompanied by leukemic transformation.

Therapeutic effect of hysterosalpingography: oil- versus water-soluble contrast media--a randomized prospective study

In a prospective randomized study, the number of pregnancies after hysterosalpingography (HSG) was estimated in 398 patients who had been infertile for longer than 1 year. Iohexol was used in 101 patients, ioxaglate in 102 patients, diatrizoate meglumine in 97 patients, and ethiodized poppy-seed oil in 98 patients. Ten months after HSG, the patient, referring physician, and/or hospital department was consulted for information about pregnancies. Questionnaires were obtained from the patients who became pregnant during the waiting period of 3 months. No differences in demographic parameters, infertility status, or diagnosis made with HSG were detected among the four contrast media groups. Significantly more patients became pregnant after HSG in the ethiodized poppy-seed oil group than in the three water-soluble contrast media groups (P less than .01). When only intrauterine pregnancies resulting in full-term births were considered, significant differences in pregnancy rates between the oil-soluble and the water-soluble contrast media groups became more obvious. In the group that received ethiodized poppy-seed oil, almost one-third of the infertile women had normal pregnancies and childbirths after HSG.

Diagnostic quality and complications of hysterosalpingography: oil- versus water-soluble contrast media--a randomized prospective study

In a prospective randomized study of 417 patients, side effects and complications of contrast media and the diagnostic quality of images obtained after hysterosalpingography (HSG) were evaluated after use of diatrizoate meglumine (104 patients), ioxaglate (105 patients), iohexol (105 patients), or ethiodized poppy-seed oil (103 patients). The authors detected no differences among these groups in the prevalence of pain during HSG. The prevalence of lower abdominal pain and vaginal bleeding after HSG was significantly lower in the group that received ethiodized poppy-seed oil than in the three other groups. The prevalence of pelvic infection or inflammation was significantly lower with ethiodized poppy-seed oil than with water-soluble media. All contrast media provided acceptable diagnostic image quality with regard to fallopian tubes, peritoneal spill, and intraperitoneal distribution. Visualization of the uterine cavity and ampullary rugae was significantly better with water-soluble media than with ethiodized poppy-seed oil, which was associated with a high conception rate and which the authors consider preferable for HSG.

Photochemistry of quinolylmethylisothioronium salts. Guanine selective DNA photocleavage reagents

Quinolylmethylisothioronium salts (1a and 4a) cleave DNA upon irradiation. The cleavage is more than 10-fold enhanced by piperidine treatment and subsequently shows a high preference for guanines. Photolysis of 1a, 2a and 4a in water at lambda greater than 300 nm resulted in photoheterolysis. Irradiation of 1a in 2-propanol gave only products from photohomolysis, irradiation of 1a in methanol and 2a and 4a in 2-propanol resulted in products from both photoheterolysis and photohomolysis. Quantum yields for the disappearance of 1a in water and 2-propanol were determined. The presence or absence of oxygen had no effect in water, whereas oxidation products were observed upon irradiation in methanol and 2-propanol in the presence of oxygen. The guanine specific DNA photoreaction is proposed to take place by alkylation at N7 via the quinolylmethyl carbocation and thus to represent a photoalkylation.