The Circadian Hormone Melatonin Inhibits Morphine-Induced Tolerance and Inflammation via the Activation of Antioxidative Enzymes

Opioids are commonly prescribed for clinical pain management; however, dose-escalation, tolerance, dependence, and addiction limit their usability for long-term chronic pain. The associated poor sleep pattern alters the circadian neurobiology, and further compromises the pain management. Here, we aim to determine the correlation between constant light exposure and morphine tolerance and explore the potential of melatonin as an adjuvant of morphine for neuropathic pain treatment. Methods: Wistar rats were preconditioned under constant light (LL) or a regular light/dark (LD) cycle before neuropathic pain induction by chronic constriction injury. An intrathecal (i.t.) osmotic pump was used for continued drug delivery to induce morphine tolerance. Pain assessments, including the plantar test, static weight-bearing symmetry, and tail-flick latency, were used to determine the impact of the light disruption or exogenous melatonin on the morphine tolerance progression. Results: constant light exposure significantly aggravates morphine tolerance in neuropathic rats. Continued infusion of low-dose melatonin (3 μg/h) attenuated morphine tolerance in both neuropathic and naïve rats. This protective effect was independent of melatonin receptors, as shown by the neutral effect of melatonin receptors inhibitors. The transcriptional profiling demonstrated a significant enhancement of proinflammatory and pain-related receptor genes in morphine-tolerant rats. In contrast, this transcriptional pattern was abolished by melatonin coinfusion along with the upregulation of the Kcnip3 gene. Moreover, melatonin increased the antioxidative enzymes SOD2, HO-1, and GPx1 in the spinal cord of morphine-tolerant rats. Conclusion: Dysregulated circadian light exposure significantly compromises the efficacy of morphine’s antinociceptive effect, while the cotreatment with melatonin attenuates morphine tolerance/hyperalgesia development. Our results suggest the potential of melatonin as an adjuvant of morphine in clinical pain management, particularly in patients who need long-term opioid treatment.

[Association of sleep quality with hypertension in the elderly of Jino nationality: a multilevel model analysis]

Objective: To evaluate the association of sleep quality with hypertension in the elderly population aged 60 years and older of Jino nationality. Methods: In August 2015, a cross-sectional population-based survey was conducted to investigate the prevalence of hypertension in 805 subjects sampled by multistage stratified and cluster sampling from the elderly population of Jino nationality, the sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI, a poor sleep group was defined as having a global PSQI score>7, a good sleep group was with a score of 7 or less), and the multilevel Logistic regression model was applied to analyze the association of sleep quality with hypertension. Results: A total of 793 eligible participants were available for analysis. Overall, 118 participants (14.9%) were in the poor sleep group, and 675 participants (85.1%) were in the good sleep group. The prevalence of hypertension, prevalence of isolated systolic hypertension, average systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the poor sleep group were significantly high than those of the good sleep group[73.7%, 22.0%, (139.2±17.7) and (82.5±10.6) mmHg (1 mmHg=0.133 kPa) vs 33.0%, 9.0%, (131.2±15.0) and (78.5±8.9) mmHg, all P<0.05]. The results of covariate-adjusted multilevel Logistic regression model indicated that subjective sleep quality (OR=2.64, 95% CI: 1.08-6.44), sleep latency (OR=2.98, 95% CI: 1.52-5.86), sleep disturbance (OR=2.93, 95% CI: 1.06-8.10), daytime dysfunction (OR=3.86, 95% CI: 1.74-8.58) and poor sleep (OR=3.98, 95% CI: 2.05-7.73) had the positive correlation with hypertension. Conclusions: The elderly population of Jino nationality with poor sleep have high SBP and DBP. There are positive associations of PSQI and its components with hypertension in the elderly population of Jino nationality.

The mediating role of Internet addiction in depression, social anxiety, and psychosocial well-being among adolescents in six Asian countries: a structural equation modelling approach

OBJECTIVES

This study examines the associations of Internet addiction with social anxiety, depression, and psychosocial well-being among Asian adolescents. A self-medication model conceptualizing Internet addiction as a mediating role in relating depression and social anxiety to negative psychosocial well-being was tested.

STUDY DESIGN

A cross-sectional survey.

METHODS

In the Asian Adolescent Risk Behavior Survey (AARBS), 5366 adolescents aged 12-18 years from six Asian countries (China, Hong Kong, Japan, South Korea, Malaysia, and Philippines) completed a questionnaire with items of the Internet Addiction Test (IAT), Social Anxiety Scale for Adolescents (SAS-A), Center for Epidemiological Studies Depression Scale (CESD), Self-Rated Health of the Nation Outcome Scales for Children and Adolescents (HoNOSCA-SR) in the 2012-2013 school year. Structural equation modelling was used to examine the mediating role of Internet addiction in depression, social anxiety, and subjective psychosocial well-being.

RESULTS

Significant differences on the scores of IAT, SAS-A, CESD, and HoNOSCA-SR across the six countries were found. The proposed self-medication model of Internet addiction received satisfactory goodness-of-fit with data of all countries. After the path from social anxiety to Internet addiction had been discarded in the revised model, there was a significant improvement of the goodness-of-fit in the models for Japan, South Korea, and the Philippines.

CONCLUSIONS

Depression and social anxiety reciprocally influenced, whereas depression associated with poorer psychosocial well-being directly and indirectly through Internet addiction in all six countries. Internet addiction mediated the association between social anxiety and poor psychosocial well-being in China, Hong Kong, and Malaysia.

Qualitative and quantitative analyses of nucleosides and nucleobases in Ganoderma spp. by HPLC–DAD-MS

A high-performance liquid chromatography-diode array detector-mass spectrometry (HPLC-DAD-MS) analytical method was developed for detection of the nucleosides and nucleobases in two species of Lingzhi, the dried sporophore of Ganoderma lucidum and G. sinense. The method, combining advantages of both DAD and MS, was successfully used to qualitatively identify for six nucleosides namely, adenosine, cytidine, guanosine, inosine, thymidine, uridine and five nucleobases namely, adenine, guanine, hypoxanthine, thymine and uracil in Lingzhi samples. Quantitative analyses showed that uridine was the most abundant nucleoside in these Lingzhi samples and the contents of nine target analytes were found to be different in pileus and stipes of the fruiting bodies and among the different species of G. spp. The established method might apply as an alternative approach for the quality assessment of Lingzhi.

A rapid method for the simultaneous determination of 11 saponins in Panax notoginseng using ultra performance liquid chromatography

A rapid ultra performance liquid chromatography coupled with photo diode array detection method (UPLC-PDA) was developed for the simultaneous determination of 11 saponins, namely notoginsenoside R1, ginsenoside Rg1, Re, Rf, Rb1, Rg2, Rc, Rb2, Rb3, Rd and Rg3 in Panax notoginseng. The analysis was performed on Acquity UPLC system with Acquity UPLC BEH C(18) column and gradient elution of water and acetonitrile in 12 min. The high correlation coefficient (r(2)>0.9968) values indicated good correlations between the investigated compounds' concentrations and their peak areas within the test ranges. The LOQ and LOD were lower to 0.2-2.4 and 0.1-1.8 ng on column, respectively. The overall intra- and inter-day variations (R.S.D.) of 11 saponins were lower than 3.1%. The developed method was successfully used for the analysis of saponins in P. notoginseng with overall recovery of 93.0-101.6% for the analytes. The results show that UPLC is a powerful tool for analysis of components in Chinese medicines.

Imaging of human aortic atherosclerotic plaques by polarization-sensitive optical coherence tomography

Optical coherence tomography (OCT) is analogous to ultrasound imaging except that it uses infrared light instead of sound. Polarization-sensitive optical coherence tomography (PS-OCT) combines the advantages of OCT and provides additional image contrast of the tested sample. We demonstrate this technique for imaging of back-reflected light, birefringence, and fast-axis orientation simultaneously in different kinds of atherosclerosis plaque. This in vitro study suggests birefringence changes in plaque are due to the prominent deposition of collagen or cholesterol by correlating PS-OCT images with histology. Thus the combination of high resolution structural imaging and birefringence detection make PS-OCT a potentially powerful tool for early assessment of atherosclerosis appearance and prediction of plaque rupture.

Long-term global retinal microvascular changes in a transgenic vascular endothelial growth factor mouse model

AIMS/HYPOTHESIS

Vascular endothelial growth factor (VEGF) plays a pivotal role in the pathogenesis of diabetic retinopathy. We investigated whether transgenic mice with moderate VEGF expression in photoreceptors (trVEGF029) developed changes similar to diabetic retinopathy and whether retinopathy progressed with time.

MATERIALS AND METHODS

Human VEGF(165) (hVEGF(165)) expression was analysed using ELISA and quantitative RT-PCR; serum glucose levels were also measured. Fundus fluorescein angiography (FA) was used to screen the degree of retinopathy from 6 weeks. Dynamic changes in the density of retinal microvasculature, as well as other changes similar to diabetic retinopathy, including retinal leucostasis, capillary endothelial cell and pericyte loss, and numbers of acellular capillaries, were quantified.

RESULTS

trVEGF029 mice were normoglycaemic and showed a moderate, short-term hVEGF(165) upregulation for up to 3 weeks. Changes in the retinal microvasculature not only mimicked those seen in diabetic retinopathy, but also showed similar pathological progression with time. FA at 6 weeks identified two phenotypes, mild and moderate, which were distinguished by the extent of vascular leakage. Quantitative analysis of diabetic retinopathy-like changes revealed that these parameters were tightly correlated with the initial degree of vascular leakage; low levels reflected slow and limited retinal microvascular changes in mild cases and high levels reflected more rapid and extensive changes in moderate cases.

CONCLUSIONS/INTERPRETATION

The data suggest that even an early short-term elevation in hVEGF(165) expression might set a train of events that lead to progressive retinopathy. Induction of many features characteristic of diabetic retinopathy in trVEGF029 enables mechanisms leading to the disease state to be examined, and provides a relevant animal model for testing novel therapeutics.

A rapid HPLC–ESI-MS/MS for qualitative and quantitative analysis of saponins in “XUESETONG” injection

'XUESETONG' injection, one of the most widely used proprietary medicines in traditional Chinese medicine, consists of total saponins made from Panax notoginseng, which is a highly valued and important Chinese medicinal herb. It is used to treat cardiovascular diseases. In order to control the quality of XUESETONG injection, a rapid HPLC-ESI-MS/MS method was developed for qualitative and quantitative determination of the saponins. The analyses were performed on SB-C18 column using gradient elution in 25 min. Full scan and time programmed selected reaction monitoring (SRM) were used for qualitative and quantitative analysis of saponins, respectively. Twenty-seven saponins were identified and nine of them including notoginsenoside R1, ginsenoside Rb1, Rb2, Rb3, Rc, Rd, Re, Rf and Rg1 were quantified. Ten XUESETONG injections were analyzed and compared. The results showed that there is a great variation among different samples. In conclusion, the developed method is rapid, accurate and sensitive for qualitative and quantitative analysis of saponins in XUESETONG injection. Moreover, it also can be used for the quality control of P. notoginseng raw material and its preparations.

Simultaneous determination of nine saponins from Panax notoginseng using HPLC and pressurized liquid extraction

A HPLC and pressurized liquid extraction (PLE) method was developed for simultaneous determination of nine saponins, including notoginsenoside R1, ginsenoside Rg1, Re, Rf, Rb1, Rc, Rb2, Rb3 and Rd in Panax notoginseng. The analysis was performed on C18 column with water-acetonitrile gradient elution and the investigated saponins were authenticated by comparing retention time and mass spectra with their reference compounds. Several methods including PLE, ultrasonication, soxhlet extraction and immersion were used for sample preparation and their extraction efficiency was compared. The results showed that PLE has the highest extraction efficiency and repeatability, which would be valuable on standardization of sample preparation for quality control of Chinese medicines. The developed HPLC and PLE is an effective approach for simultaneously quantitative determination of sapoinins in P. notoginseng, which could be used for quality control of P. notoginseng and its preparations.

Simultaneous determination of ergosterol, nucleosides and their bases from natural and cultured Cordyceps by pressurised liquid extraction and high-performance liquid chromatography

A simple method is described for the simultaneous determination of ergosterol, nucleosides and their bases in Cordyceps. The samples were extracted by using pressurised liquid extraction (PLE). The effects of experimental variables, such as solvent, temperature, static extraction time and cycles, on PLE efficiency have been studied. The results showed a strong influence of the solvent and temperature on extraction efficiency of PLE. The determination was achieved by high-performance liquid chromatography (HPLC) using a Zorbax NH2 analytical column (250 x 4.6 mm i.d., 5 microm) with diode-array detector (DAD). The automated preparation of the sample permits a very fast analysis which is an important goal for routine purpose.

Potential long-term inhibition of ocular neovascularisation by recombinant adeno-associated virus-mediated secretion gene therapy

Neovascularisation (NV) within the eye often results in visual loss. Vascular endothelial growth factor (VEGF) has been implicated in the development of ocular NV. Previous studies have shown that VEGF antagonists successfully suppressed retinal and choroidal NV in animal models. However, the systemic approach and transient nature of the delivery systems used in these studies hinder therapeutic application. To achieve stable and localised ocular anti-angiogenic therapy, we explored the use of recombinant adeno-associated virus (rAAV)-mediated secretion gene therapy (SGT). In this study, we generated a rAAV vector encoding soluble VEGF receptor 1, sFlt-1 (AAV-CMV.sflt) and determined its ability to inhibit cautery-induced corneal NV and laser-induced choroidal NV. Delivery of AAV-CMV.sflt into the anterior chamber resulted in transgene expression in the iris pigment epithelium and corneal endothelium, which reduced the development of corneal NV in the stroma of cauterised rats by 36% compared with cauterised control groups (P = 0.009). Subretinal delivery of AAV-CMV.sflt near the equator of the eye also suppressed choroidal NV at the laser lesions around the optic nerve by 19% (P = 0.002), indicating that there was diffusion of the secreted anti-angiogenic protein across the retina. Both results suggest that the long-term suppression of ocular NV is possible through the use of stable rAAV-mediated SGT.

Carbon dioxide flux density in cultivated rice paddy field

The carbon dioxide flux density in a subtropical cultivated rice paddy field were determined over four crop seasons (two consecutive years) at five stages of rice plant development, transplanting, active tillering, booting, flowering and ripening, and an idle period between crops. During 24 h sampling periods at those stages, the CO2 flux densities were measured and found to be -2,000 to 55,000 mg CO2/m2/day in the first year and 600 to 29,000 mg CO2/m2/day in the second year in acrylic chambers covering rice plants. The CO2 flux densities in glass domes without plants but with soil were -700 to 6,000 mg CO2/m2/day in the first year and 147 to 4,500 mg CO2/m2/day in the second year. The data for the CO2 flux density over an entire year are extrapolated. Although our non-controlled environment experiments have inherent drawbacks, the collected data indicate that continuous rice cultivation has a tendency to result in increased CO2 emissions.

Inhibition of angiogenesis by adenovirus-mediated sFlt-1 expression in a rat model of corneal neovascularization

Pathological angiogenesis, or the production of new capillary vessels from preexisting vasculature, within the eye is a serious event that often leads to blindness. Upregulation of vascular endothelial growth factor (VEGF) has been linked to neovascularization in the eye, suggesting that it could be a suitable target to inhibit angiogenic changes. This work investigated whether the presence of a proven antiangiogenic factor, the soluble variant of the VEGF receptor, sFlt-1, in the anterior chamber is sufficient to inhibit new vessel formation in the cornea in an animal model of corneal neovascularization. A recombinant adenovirus vector that can mediate efficient in vivo gene transfer and expression in ocular cells was selected as a delivery agent. We have shown that after the injection of Ad.betagal into the anterior chamber of normal and cauterized rat eyes, corneal endothelial cells and cells of the trabecular meshwork were efficiently transduced and that beta-galactosidase (beta-Gal) expression was maintained up to 10 days postinjection. Cauterization significantly increased the amount of immunoreactive VEGF in vehicle- or Ad.null-injected animals (t test, p < 0.001 and p < 0.001, respectively). However, when cauterization was combined with Ad.sflt injection there was no statistically significant increase in the amount of immunoreactive VEGF (p = 0.12). The injection of Ad.sflt into the anterior chamber slowed or inhibited VEGF-induced angiogenic changes. After cauterization, 100% of uninjected and vehicle-injected and 82% of Ad.null-injected animals developed moderate to severe corneal angiogenesis in contrast to 18% of Ad.sflt-injected animals. These in vivo results suggest that the transient presence of antiangiogenic agents in the anterior chamber can be successfully used to inhibit the development of corneal angiogenesis.

Identification and characterization of S2V, a novel putative siglec that contains two V set Ig-like domains and recruits protein-tyrosine phosphatases SHPs

We describe the molecular cloning and characterization of S2V, a novel sialic acid binding immunoglobulin-like lectin. The cDNA of S2V encodes a type 1 transmembrane protein with four extracellular immunoglobulin-like (Ig-like) domains and a cytoplasmic tail bearing a typical immunoreceptor tyrosine-based inhibitory motif (ITIM) and an ITIM-like motif. A unique feature of S2V is the presence of two V-set Ig-like domains responsible for the binding to sialic acid, whereas all other known siglecs possess only one. S2V is predominantly expressed in macrophage. In vivo S2V was tyrosine-phosphorylated when co-expressed with exogenous c-Src kinase. Upon tyrosine phosphorylation, S2V recruits both Src homology 2 (SH2) domain-containing protein-tyrosine phosphatases SHP-1 and SHP-2, two important inhibitory regulators of immunoreceptor signal transduction. These findings suggest that S2V is involved in the negative regulation of the signaling in macrophage by functioning as an inhibitory receptor. When expressed in COS-7 cells, S2V was able to mediate sialic acid-dependent binding to human red blood cells, suggesting that S2V may function through cell-cell interaction.

Controlled production of active cathepsin D in retinal pigment epithelial cells following adenovirus-mediated gene delivery

The transduction of a low cathepsin D-producing retinal pigment epithelial cell line with a recombinant adenovirus, Ad.proCatD, carrying a viral promoter and the precursor form of the lysosomal enzyme cathepsin D, procathepsin D, led to the upregulation of proCatD expression. However, the resultant aspartic protease activity did not exceed that observed in normal primary human retinal pigment epithelial cells. Following the injection of Ad. proCatD into rat eyes, immunohistochemistry and Western blot analysis localized the expression of procathepsin D to the retinal pigment epithelial cell layer and to the sclera/choroid/retinal epithelial cell layers, respectively. This upregulation of procathepsin D expression was accompanied by a limited increase in aspartic protease activity. The injected eyes did not demonstrate any of the retinal changes that have been associated with the overproduction and secretion of active cathepsin D. Immunoelectronmicroscopy of Ad.proCatD-transduced retinal pigment epithelial cells demonstrated the presence of cathepsin D not only in cytoplasmic vesicles and lysosomes but also in the nucleoli and, less strongly, elsewhere in euchromatic regions of some 10% of cells. In spite of the upregulated expression of procathepsin D, the production of active cathepsin D in Ad.proCatD-transduced retinal pigment epithelial cells was strictly controlled. It is proposed that active cathepsin D production is controlled at the point of posttranslational modification by an intranuclear feedback mechanism initiated by the relative excess of procathepsin D in Ad. proCatD-transduced retinal pigment epithelial cells.

The use of adenovirus-mediated gene transfer to develop a rat model for photoreceptor degeneration

PURPOSE

To investigate the effects of recombinant adenovirus-mediated downregulation of cathepsin S (CatS) on the retinal pigment epithelium and/or neural retina in vivo.

METHODS

The expression of green fluorescent protein (gfp) after subretinal injection of a recombinant adenovirus, Ad.gfp, into rat eyes was first established by in vivo fundus fluorescence photography and fluorescence microscopy. The autofluorescent debris accumulation in Ad.CatSAS (recombinant adenovirus carrying the antisense CatS gene)injected rat eyes was monitored by fluorescence microscopy, and the antisense CatS RNA expression was demonstrated by in situ hybridization. Changes in the retinal morphology were assessed by light microscopy. ResuLTS. The gfp expression was present in 30% to 90% of the injection area at 3 days and was absent 9 days after Ad.gfp injection. In Ad.CatSAS-injected eyes, the expression of antisense CatS RNA was demonstrated by in situ hybridization. Autofluorescent debris accumulation was significantly higher in Ad.CatSAS-injected eyes than in control eyes. The shortening of photoreceptor outer segments in Ad.CatSAS-injected eyes coincided with intense autofluorescent debris accumulation. The number of layers of photoreceptor cells decreased with time and were 11, 9, and 8 at 7, 14, and 28 days after Ad.CatSAS injection, respectively. In control eyes, the number of layers of photoreceptor cells (14) remained unchanged.

CONCLUSIONS

These results demonstrate that recombinant adenovirus-mediated transient modulation of gene expression in retinal pigment epithelial (RPE) cells could induce changes in the retina, and, in spite of the low expression of endogenous CatS in RPE cells, this enzyme plays an important role in maintenance of normal retinal function.

Expanded-spectrum nonnucleoside reverse transcriptase inhibitors inhibit clinically relevant mutant variants of human immunodeficiency virus type 1

A research program targeted toward the identification of expanded-spectrum nonnucleoside reverse transcriptase inhibitors which possess increased potency toward K103N-containing mutant human immunodeficiency virus (HIV) and which maintain pharmacokinetics consistent with once-a-day dosing has resulted in the identification of the 4-cyclopropylalkynyl-4-trifluoromethyl-3, 4-dihydro-2(1H)quinazolinones DPC 961 and DPC 963 and the 4-cyclopropylalkenyl-4-trifluoromethyl-3, 4-dihydro-2(1H)quinazolinones DPC 082 and DPC 083 for clinical development. DPC 961, DPC 963, DPC 082, and DPC 083 all exhibit low-nanomolar potency toward wild-type virus, K103N and L100I single-mutation variants, and many multiply amino acid-substituted HIV type 1 mutants. This high degree of potency is combined with a high degree of oral bioavailability, as demonstrated in rhesus monkeys and chimpanzees, and with plasma serum protein binding that can result in significant free levels of drug.

Preferential adenovirus-mediated transduction of cells at the sites of laser photocoagulation in the rat eye

PURPOSE

This study aimed to investigate the feasibility of recombinant adenovirus-mediated gene transfer into cells implicated in the development of choroidal neovascularization (CNV).

METHODS

A rat model of CNV which used laser photocoagulation was developed. Gene delivery into the laser spots was investigated following subretinal injection of recombinant adenoviruses, AdRSVlacZ, AdCMVlacZ or AdCMVgfp. Immunohistochemical analysis was performed using a proliferating cell nuclear antigen antibody and a cytokeratin-specific antibody to identify the cell types transduced by the recombinant adenoviruses.

RESULTS

At 7 days post-injection, lacZ expression was detected in 51.6 +/- 13.2% and 71.2 +/- 19.3% of laser spots in AdRSVlacZ- and AdCMVlacZ-injected eyes, respectively. By 28 days post-injection, lacZ expression was only present in AdCMVlacZ-injected eyes. In vivo fundus fluorescent photography of AdCMVgfp-injected eyes detected gfp expression in 79.9 +/- 12.7% and 35.6% +/- 19.7% of laser spots at 4 and 7 days post-injection, respectively. Although fundus fluorescent photography did not detect the gfp signal at 10 days post-injection, fluorescent microscopy revealed a gfp signal in 81.3 +/- 6.0% of laser spots. Immunohistochemical analysis detected retinal pigment epithelial (RPE) cells as the most predominant proliferating cell type in the laser spots, although several other proliferating cell types were also identified. X-gal staining showed that the majority of transduced cells were those present in the laser spots.

CONCLUSIONS

It is proposed that following laser photocoagulation, proliferating RPE cells are susceptible to adenovirus-mediated gene delivery and that they may be suitable targets for the delivery of antiangiogenic factors by recombinant adenoviruses in order to inhibit developing CNV membranes.

Determination of bisnafide, a novel bis-naphthalimide anticancer agent, in human plasma by high-performance liquid chromatography with UV detection

A simple, specific, and sensitive high-performance liquid chromatographic (HPLC) assay utilizing ultraviolet (UV) detection for the determination of bisnafide in human plasma was developed, validated, and applied to plasma samples from patients undergoing cancer therapy. Plasma samples, containing an internal standard, XE842, were first deproteinized with 2.0 ml acetonitrile, and subsequently, 1.0 ml and pH 9 boric acid-potassium chloride-sodium hydroxide buffer (0.1 M) was added. To this mixture, 9.0 ml of ethyl ether was added then vortex mixed. Following centrifugation, the ether layer was back-extracted into 250 microliters of 0.1 M phosphoric acid, then removed by vacuum aspiration. A portion of the remaining acid layer was directly injected onto the HPLC. Bisnafide was quantified using a Shiseido Capcell Pak C8 HPLC column and ultraviolet detection (274 nm). The lower limit of quantification was 10 ng ml-1 using 1.0 ml plasma. The intraday precision (RSD) ranged from 2.7 to 8.6% over a concentration range of 10-1000 ng ml-1. The interday precision (RSD) ranged from 5.6 to 11.5%. Overall mean accuracy was +/- 5.2%. The drug was stable in frozen heparinized human plasma stored at -20 degrees C for at least 1 year and stable throughout at least two freeze-thaw cycles. This method was successfully utilized for quantifying plasma concentrations needed to study the clinical pharmacokinetics of bisnafide in patients undergoing cancer therapy.

Recombinant adenovirus-mediated gene delivery into the rat retinal pigment epithelium in vivo

PURPOSE

The present paper describes changes following the subretinal injection of a recombinant replication-deficient adenovirus carrying the beta-galactosidase reporter gene construct into the rat retina.

METHODS

Ad.RSV.betagal-mediated transduction of rat retinal pigment epithelium (RPE) cells in vitro and in vivo was examined following X-gal staining.

RESULTS

There was a low level of beta-galactosidase expression in the RPE cells at 4 days postinjection. At 7 days postinjection, a strong transgene expression was present in RPE cells and the expression was maintained at 14 days postinjection. Except for the accumulation of cells at the site of the injection, the morphology of the rest of the retina remained normal.

CONCLUSION

These results demonstrate that the RPE layer can be successfully targeted for gene delivery in the rat.

Modulation of cathepsin D activity in retinal pigment epithelial cells

This project used retinal pigment epithelial (RPE) cells to investigate the effects of up- and down-regulation of cathepsin D expression on the processing of cathepsin D and on the normal phagocytic and digestive function of these cells. RPE cells were transfected with a pHbetaApr-1-neo vector construct carrying the full-length sequence of the translated region of human cathepsin D in sense and antisense directions. Transfected cells were characterized for the presence and expression of the transgene by PCR amplification using transgene-specific primers. Total aspartic proteinase activity present in transformed RPE cells was measured by an enzyme assay using haemoglobin as substrate. Flow cytometry was used to quantify phagocytosis of fluorescein isothiocyanate-labelled rod outer segments (ROS), and lysosomal digestion of ROS was monitored by immunofluorescence. A 435 bp fragment was present in RPE cells carrying the cathepsin D transgene in sense and antisense orientations after PCR amplification. Expression of both 52 kDa procathepsin D and 34 kDa active cathepsin D was significantly up-regulated in sense cathepsin D-transfected RPE cells and down-regulated in RPE cells transfected with antisense cathepsin D. No other forms of cathepsin D were detected in the transfected cells, suggesting that, if pseudo-cathepsin D exists in RPE cells in vivo, it requires the presence of unknown specific regulatory elements. The up- and down-regulation of cathepsin D expression was further confirmed by enzyme assay. Transfected cells retained their phagocytosing ability after ROS challenge and maintained their ability to process ROS. The processing of ROS was significantly slower in RPE cells transfected with antisense than control vector or in sense-cathepsin D-transfected cells. These results demonstrate that cathepsin D is a major proteolytic enzyme participating in the lysosomal digestion of photoreceptor outer segments.

The in vivo expression patterns of individual type I interferon genes in murine cytomegalovirus infections

Type I interferon (IFN) family has more than 10 structurally related subtypes of alpha IFN (IFNA) genes and a single beta IFN (IFNB) gene. This study examined the expression of MuIFNA1, A4, A5, A6, A9 and MuIFNB mRNAs in the livers and spleens of MCMV-infected mice at 2, 4 and 6 h post infection. The three strains of inbred mice studied were C57BL/6, B6.C-H-28c and BALB/c. B6.C-H-28c strain is a congenic strain of C57BL/6 genomic background. Detection of the specific mRNAs was by an established semiquantitative procedure based on reverse transcription and PCR amplification followed by differential hybridization to specific oligonucleotides. Similar expression patterns of the type I IFN mRNAs were found in C57BL/6 and B6.C-H-28c strains of mice. However, when the genotype was significantly different (BALB/c), a different expression pattern of IFN mRNAs was seen. Differences in the expression patterns of the type I IFN mRNAs was also seen between the livers and spleens of a given mouse strain. Thus, the present study indicates that mouse genotype appears to be a major determinant of the subtype response pattern seen in vivo and that tissue-type can influence the subtype response pattern seen within a given mouse genotype.

The in vitro expression patterns of individual type I interferon genes in Newcastle disease virus infected murine splenocytes and fibroblasts

Murine type I interferon levels present in mice sera following Newcastle disease virus infections are influenced by the If-1 locus. Sera interferon levels in C57BL/6 mice (If-1h allele) are 10- to 15-fold higher than in BALB/c mice (If-1(1) allele). The B6.C-H-28c strain, which carries BALB/c If-1(1) allele on C57BL/6 genomic background, has low interferon levels in sera. This study examined the expression of interferon alpha 1, alpha 4, alpha 5, alpha 6, alpha 9 and beta mRNAs at 7 hr after Newcastle disease virus infection of primary cells (splenocytes and mouse embryo fibroblasts) from C57BL/6, B6.C-H-28c and BALB/c mouse genotypes. Total RNA from these cells was reverse transcribed and all known type I interferon subtypes were amplified. The products were identified by differential hybridization to a panel of subtype specific oligonucleotides. The results show that the pattern of interferon subtypes examined in splenocytes did not differ between If-1h and If-1(1) allele carrying C57BL mice. However, when the genotype was different (BALB/c splenocytes) the pattern of type I interferon mRNAs seen was altered. This genotype-dependent expression was also seen in newcastle disease virus infected fibroblasts. Within a given mouse strain, there were also differences in the subtype response patterns detected in fibroblasts compared with those seen in splenocytes. In conclusion, the present study indicates that mouse genotype appears to be a major determinant of the subtype response pattern seen and tissue specific pattern differences are present within a given mouse genotype.

Alpha/beta interferons increase host resistance to murine AIDS

Murine AIDS (MAIDS) is caused by a defective retrovirus present in the LP-BM5 murine leukemia virus mixture. Strains of inbred mice differ in resistance to MAIDS development; some are susceptible (e.g., C57BL/6), while others are resistant (e.g., CBA and B10.BR). As an early block to viral replication in resistant mice has been demonstrated previously by PCR studies, we postulated that alpha/beta interferons (IFN-alpha/beta) may be involved in resistance to MAIDS. Susceptible C57BL/6 mice infected with LP-BM5 were treated with IFN-alpha/beta or Newcastle disease virus. Newcastle disease virus induces high endogenous IFN-alpha/beta production in mice. Both treatments delayed the development of MAIDS, as assessed by splenomegaly and T- and B-cell proliferation. In addition, an IFN-alpha/beta response was detected by reverse transcription-PCR and dot blotting 3, 6, and 9 h after LP-BM5 infection in resistant mice but not in susceptible mice. These results suggest that the ability to produce IFN-alpha/beta in response to LP-BM5 infection may contribute to host resistance to MAIDS.

Production of monoclonal and polyclonal antibodies against various haemoglobins for the detection of thalassaemias

The thalassaemias are a major group of genetic disorders in Southeast Asia that affect the production of the alpha-globin chain (alpha-thalassaemia) or the beta-globin chain (beta-thalassaemia) of the haemoglobin. As a result of defective globin chain synthesis, individuals with this disorder show varying degrees of anaemia due to ineffective erythropoiesis and haemolysis. The presence of abnormal haemoglobins in thalassaemia patients has enabled the detection of thalassaemia using immunological methods which have certain advantages over the conventional diagnostic methods. This paper reviews the application of various types of antibodies against the different types of haemoglobins used for the detection of thalassaemia. The developed antibodies include the polyclonal antibodies against Hb Bart's and Hb H; monoclonal antibodies (mab) against Hb H, used in a sandwich enzyme-linked immunosorbent assay (ELISA), for detecting carriers of (--SEA/) deletion and deletions involving the complete zeta-alpha-globin gene cluster, such as (--alpha FIL/), (--alpha THAI/) and (--HW/), which are the common deletional alpha-thalassaemias in Southeast Asians; mab against zeta-globin chains used in an immunocytological test, for the detection of adult carriers of (--SEA/) deletion except for (alpha 20.5/), (--alpha FIL/) and (--alpha THAI/) (this simple test is useful in identifying couples at risk of conceiving foetuses afflicted with the Hb Bart's hydrops foetalis syndrome due to homozygous alpha-thalassaemia); mab against Hb A2 and beta- and gamma-globin chains used for the quantitation of Hb A2 in beta-thalassaemia and the diagnosis of beta-thalassaemia major in foetuses respectively; other mabs produced to date include those specific to haemoglobins D-Los Angeles, J-Baltimore, O-Arab and J-Paris-I.

Interferon-alpha inhibits erythropoietin-induced proliferation, but not differentiation, and restricts erythroleukemia development

The immature erythroid cell line J2E responds to erythropoietin (Epo) by proliferating and terminally differentiating into hemoglobin-synthesizing red blood cells. These cells produce a rapid, fatal erythroleukemia in mice characterized by hepatosplenomegaly and severe anemia. The aim of this study was to investigate the effects of murine interferons-alpha (MuIFN-alpha) on J2E cells in vitro and in vivo. Here we show that in culture MuIFN-alpha inhibited the Epo-induced proliferation of J2E cells but did not interfere with differentiation. When mice with J2E erythroleukemias were treated with MuIFNs in vivo, an extension of their life span was observed. Moreover, numerous necrotic lesions of infiltrating leukemic cells were detected in the spleens of these mice. Finally, ex vivo treatment of leukemic bone marrow cells with Epo and MuIFNs delayed mortality even further. It was concluded that MuIFNs (1) suppressed the proliferation of J2E cells in vitro but did not affect Epo-induced differentiation, and (2) inhibited the progress of erythroleukemias, especially in combination with Epo.

A rapid fatal erythroleukemia caused by J2E cells can be treated ex vivo with erythropoietin

The J2E cell line is an immature erythroid line which terminally differentiates in response to erythropoietin (epo), producing mature, hemoglobin-synthesizing red blood cells. We have shown that when these cells were injected into mice a rapid and fatal erythroleukemia developed with symptoms of severe anemia and hepatosplenomegaly. Southern blotting demonstrated that the leukemic cells were the introduced J2E cells. In addition to spleen and liver, the bone marrow was a major site of leukemic cell infiltration, and when grown in vitro leukemic cells from bone marrow remained responsive to erythropoietin. We reasoned, therefore, that treatment of mice with this hormone should alleviate the erythroleukemia, but regular injections of epo in vivo failed to arrest the progress of the disease. However, when bone marrow from leukemic mice was exposed continuously to the hormone ex vivo, before reinfusion into naive recipients, a marked extension in life span was observed. It was concluded that ex vivo epo treatment could be used therapeutically for J2E cell erythroleukemias.

Binding of fosphenytoin, phosphate ester pro drug of phenytoin, to human serum proteins and competitive binding with carbamazepine, diazepam, phenobarbital, phenylbutazone, phenytoin, valproic acid or warfarin

The protein binding of [14C]fosphenytoin, (3-phosphoryloxy-methyl phenytoin disodium), a phosphate ester prodrug of phenytoin sodium, to human serum proteins, serum albumin and alpha 1-acid glycoprotein was determined by ultrafiltration. The mean +/- SD% of fosphenytoin bound to human serum proteins was 95.7 +/- 0.48%. Binding to albumin (36.5 mg/ml) decreased linearly from 89.2 to 67.3% when the fosphenytoin concentration was increased from 6 to 200 micrograms/ml. Fosphenytoin was weakly bound to alpha 1-acid glycoprotein (13.3%). Simultaneous incubation with high concentrations of carbamazepine (10 micrograms/ml) and diazepam (5 micrograms/ml) or therapeutic concentrations of phenytoin (10 micrograms/ml) had no effect on the binding of fosphenytoin to human serum proteins. High concentrations of phenobarbital (160 micrograms/ml), phenytoin (50 micrograms/ml), or valproic acid (500 micrograms/ml), however, caused slight, but significant, increases in the free fraction of fosphenytoin in serum protein. Phenylbutazone and sulfisoxazole resulted in a 48% increase in fosphenytoin free fraction while warfarin had a slight (8%), but significant, increase in free fraction of fosphenytoin. It was concluded that the concentration of albumin was the most important determinant for the plasma free fraction of fosphenytoin in man. Potential increase in fosphenytoin clearance may be observed in hypoalbuminemia.

Determination of DuP 128, an ACAT inhibitor and its sulphoxide and sulphone metabolites in human plasma by liquid chromatography

A sensitive and specific high-performance liquid chromatographic (HPLC) method with fluorescence detection was developed for the simultaneous determination of DuP 128 (N'-(2,4-difluorophenyl)-N-[5-(4,5-diphenyl-1H-imidazol-2-ylthio)p entyl]-N- hepthylurea), an ACAT inhibitor, its sulphone metabolite (XB277), and the separate determination of sulphoxide metabolite (XC164) in human plasma. After deproteinizing plasma samples with acetonitrile, the organic layer, created by adding approximately 0.25 g of NaCl, was removed, evaporated to dryness, and the residue then reconstituted with 400 microliters of acetonitrile. The acetonitrile layer was washed with 5 ml of hexane and then 50 microliters was injected into the HPLC. DuP 128 and XB277 were simultaneously quantified using a YMC basic column and fluorescence detection (lambda Ex = 270 nm and lambda Em = 385 nm). XC164 was quantified using a Waters microBondpack C18 reversed-phase column and fluorescence detection (lambda Ex = 270 nm and lambda Em = 365 nm). The relationship between the peak height and plasma concentrations best fit a power curve and showed an average correlation coefficient of > 0.99 over a concentration range of 1-200 ng ml-1 for DuP 128 and XC164 and 2.5-200 ng ml-1 for XB277. Good intraday and interday assay precisions (RSD < 10%) and accuracy (< 14%) for all three compounds were observed. The methods were sufficiently sensitive and selective to quantify plasma concentrations of DuP 128 and its sulphoxide and sulphone metabolites after oral administration of single or multiple dose(s) of > 350 mg of DuP 128 to healthy subjects.

Biological activities of recombinant murine interferons alpha 1 and alpha 4: large difference in antiproliferative effect

The mature forms of two recombinant murine interferons alpha, alpha 1 and alpha 4, have been expressed in vitro using an established transcription and translation system. The relative specific antiviral activity, antiproliferative activity and the natural killer cell stimulating activity of both subtypes were compared in vitro. While the antiviral and natural killer cell stimulating activities of the 2 subtypes were similar, the relative antiproliferative activities varied markedly. On the basis of equal molar inputs, MuIFN-alpha 1 had less than 8% of the antiproliferative activity of MuIFN-alpha 4. This data shows that a large functional difference exists between these two subtypes which are known to be expressed at different levels in mouse L-cells in vitro.

Rapid high level production and purification of recombinant murine and human interferons alpha from Escherichia coli

The availability of large quantities of pure interferon alpha (IFN-alpha) subtypes for in vivo studies has often proved difficult. This paper presents details on the use of the commercially available pGEX expression system for the production and purification of milligram (mg) quantities of recombinant Murine (Mu) and Human (Hu) IFNs-alpha-1 in Escherichia coli. Initially a fusion product is made which can be rapidly purified on a glutathione-sepharose 4B affinity matrix. Biologically active IFN-alpha can then be released from the matrix by cleavage with the restriction protease activated factor X (FXa+7,++). Routine yields of the final products were in the range of 0.5 to 2.0 mg/l of original culture.

Relative antiviral activity of in vitro-synthesized murine interferon-alpha 4 and -alpha 1

Murine interferon-alpha 4 (MuIFN-alpha 4) is notable among the MuIFN-alpha subtypes because it lacks 5 amino acids corresponding to positions 103-107 of the other subtypes, yet is the most highly expressed subtype. Site-directed in vitro mutagenesis has been used to modify the genes coding for MuIFN-alpha 4 and MuIFN-alpha 1. The modifications have allowed (i) the in vitro expression of the mature form of each MuIFN-alpha subtype and (ii) the insertion of five amino acids, corresponding to amino acid positions 103-107 of MuIFN-alpha 1, into the MuIFN-alpha 4 sequence. In contrast to previously published data MuIFN-alpha 4 and MuIFN-alpha 1 show only a twofold difference in antiviral activity, with MuIFN-alpha 4 being the more active subtype. In keeping with this observation, it was also found that insertion of the five "missing" amino acids into MuIFN-alpha 4 resulted in an analogue MuIFN-alpha with antiviral activity equivalent to MuIFN-alpha 1. It may be inferred from this work that the deletion of amino acids 103-107 (QVGVQ) is solely responsible for the difference in antiviral activity between MuIFN-alpha 4 and MuIFN-alpha 1.

Pharmacokinetics, pharmacodynamics, and minimum effective clinical dose of intravenous nicardipine

Nicardipine hydrochloride was administered intravenously to two groups of hypertensive patients: one group of 37 patients with mild to moderate hypertension and one group of 20 patients with severe hypertension. In the first group, doses of 0.5, 1, 2, and 4 mg/hr, as well as placebo, were infused for 48 hours in a double-blind fashion. Blood pressure and heart rate were monitored for this period and for the 24 hours after the infusion was discontinued. Significant decrements in blood pressure were noted with all doses; 4 mg/hr produced lowering that was greater than all other doses; 1 and 2 mg/hr produced lowering that was greater than 0.5 mg/hr but that were not different from each other. Excellent correlation of blood pressure reduction and plasma level was observed and linear kinetics existed. In the severe hypertensive patients, 1, 2, 4, 5, and 8 mg/hr were infused to established minimal and ineffective doses. One milligram per hour was an ineffective dose; 4, 5, and 8 mg/hr all produced significant reductions over the course of the study that were undistinguishable from each other. Two milligrams per hour produced modest reductions in blood pressure. Blood pressure reduction also correlated with plasma levels in the severe hypertensive group.

Hepatic arterial embolization in patients with unresectable hepatocellular carcinoma--a randomized controlled trial

A randomized controlled trial of hepatic arterial embolization was conducted in 63 consecutive patients who had unresectable but still embolizable hepatocellular carcinoma. Patients were randomized into three groups. Patients in group 1 received multiple hepatic arterial embolizations; patients in group 2 were given hepatic arterial embolization once, followed by monthly chemotherapy with high doses of 5-fluorouracil; and patients in group 3 received only monthly chemotherapy with high doses of 5-fluorouracil. Complete response was achieved in only 1 patient who received multiple hepatic arterial embolizations. Partial responses were observed in 13 patients (61.9%) in group 1, 10 patients (47.6%) in group 2, and 2 patients (9.5%) in group 3. The survival rates of patients in group 1 at the end of the ninth, 12th, 15th, 18th, and 21st months were 53.2%, 42.2%, 42.2%, 42.2%, and 42.2%, respectively, which were not significantly different from those of patients in group 2 but were better than the survival rates of patients in group 3. The results suggest that hepatic arterial embolization is an effective palliative treatment that prolongs survival of patients with unresectable hepatocellular carcinoma.

Quantitation of the ultra short acting beta-adrenergic antagonist flestolol in blood by liquid chromatography

A sensitive, specific, reproducible, and convenient high-performance liquid chromatographic (HPLC) assay was developed for quantitation of the new ultra short acting beta-adrenergic antagonist, flestolol (1), in whole blood. The instability of the compound in blood was overcome by the esterase inhibitor, NaF, and deproteinization of blood samples with CH3CN:CH2Cl2 (2:5). The internal standard was p-ethoxyphenethyl alcohol. The compounds were back extracted from the CH3CN:CH2Cl2 phase into a small volume of pH 3-4 phosphate buffer and then separated on a reversed-phase C18 column with 0.05 M phosphate buffer (pH 3-4) in acetonitrile (4.6:1) as the mobile phase, and detected with an UV detector at 229 nm. The assay was linear with a blood concentration range from 10 to 1270 ng/mL (r2 greater than 0.998, p greater than 0.01), and reproducible with an overall CV of 8%. The assay procedure was used to determine the blood levels of flestolol intravenously infused into a male dog for 105 min at 230 micrograms/kg/min. The steady-state unchanged drug concentration of 5 micrograms/mL in blood was achieved within 10-20 min and declined biexponentially to 0.02 microgram/mL at 6 h following termination of the infusion.

Effect of infusion administration set on the delivery rate and plasma concentration of nitroglycerin in dogs

A randomized crossover study with eight dogs was carried out to determine whether the in vitro difference observed in the delivery of nitroglycerin using polyvinyl chloride (PVC) and polyethylene (PE) infusion sets would result in a measurable difference in steady-state plasma concentration. At the same apparent infusion rate of 40 micrograms/min, PVC infusion sets produced steady-state plasma nitroglycerin concentrations that were only 40% of those generated with PE sets (p less than 0.0001). Attainment of steady-state drug levels appeared more rapid with the PE administration sets, but in three out of eight animals, these infusion systems appeared to produce a "bolus" dosing effect. PE sets did not reduce the variability in plasma nitroglycerin concentration observed with PVC sets.

Pharmacokinetic and pharmacodynamic studies of acute interaction between warfarin enantiomers and chloramphenicol in rats

The purpose of this investigation was to explore the mechanisms and possible stereoselectivity of the interaction between warfarin and chloramphenicol in rats. Chloramphenicol had no apparent effect on the serum protein binding of R-(+)-warfarin or S-(-)-warfarin in vitro or in vivo. Treatment with i.p. chloramphenicol, 50 mg/kg every 4 hr or 30 mg/kg every 6 hr, decreased the plasma clearance of free warfarin by one-half or more, with no apparent stereoselectivity. The volume of distribution was not significantly affected; the half-life of each warfarin enantiomer was appreciably increased by chloramphenicol. Treatment with chloramphenicol had no apparent effect on relative liver size and on serum aspartate aminotransferase activity. Prothrombin complex activity in plasma was not affected by in vitro addition or in vivo administration of chloramphenicol alone. Chloramphenicol treatment did not affect significantly the elimination kinetics of endogenous prothrombin complex activity and the plasma concentration of free R-(+)-warfarin or S-(-)-warfarin required to decrease prothrombin complex activity synthesis rate to one-half of normal. It appears that the pronounced potentiation of the anticoagulant effect of warfarin by chloramphenicol is due only to inhibition of warfarin metabolism and that this effect is not stereoselective.

Pharmacokinetic and pharmacodynamic studies of acute interaction between warfarin enantiomers and metronidazole in rats

This investigation was designed to determine if the reported stereoselectivity of the pharmacokinetic interaction between warfarin and metronidazole in humans occurs also in rats and if the potentiation of the anticoagulant effect of warfarin can be ascribed solely to inhibition of warfarin metabolism by metronidazole. Metronidazole had no effect on the serum protein binding of racemic warfarin in vitro over a wide concentration range but decreased the protein binding of R-(+)-warfarin and S-(-)-warfarin in vivo, perhaps indirectly through metabolite(s). Treatment with i.p. metronidazole, 100 mg/kg every 6 hr, decreased the plasma clearance of free warfarin ("intrinsic clearance"). This inhibitory effect was more pronounced with S-(-)-warfarin than with R-(+)-warfarin (congruent to 60 and congruent to 30%, respectively). Metronidazole did not affect plasma prothrombin complex activity in vitro but reduced it in vivo. Metronidazole treatment increased the elimination rate constant for endogenous prothrombin complex activity and decreased the plasma concentration of free R-(+)-warfarin required to decrease prothrombin complex activity synthesis rate to one-half of normal (there were insufficient data to determine the effect of metronidazole on the activity of the other enantiomer). It is concluded that metronidazole preferentially inhibits the metabolism of S-(-)-warfarin in rats as in humans but that (at least in rats) the stereoselectivity is not absolute. Moreover, metronidazole has an indirect inhibitory effect on warfarin protein binding in vivo and also affects the pharmacodynamics of warfarin as well as the blood clotting process per se.

Chemical characterization of the persistent fraction of hydroxyethyl starch in rat serum and spleen

Hydroxyethyl starch (HES) found in rat serum and spleen after single and daily administrations of 0.9 g/kg for 1 week was characterized by gas-liquid chromatography. There was very little difference in the degree of substitution (D.S.) and molar substitution (M.S.) of HES in serum samples obtained at 1 hour and 57 days after multiple doses and of HES in spleen samples obtained at 1 hour and 168 days after a single dose of HES. The small increase in D.S. and M.S. was due to a decrease in the glucose content and not due to a change in the ratio of mono- to poly-substituted glucoses.

Kinetics of esmolol, an ultra-short-acting beta blocker, and of its major metabolite

Esmolol is an ultra-short-acting beta blocker. Its kinetics was studied in eight healthy subjects after continuous intravenous infusion of 400 micrograms/kg/min over 2 hr. The concentrations of esmolol and its major metabolite, 3-[4-(2-hydroxy-3-[isopropylamino]propoxy)phenyl]propionic acid, in blood and urine were determined by gas chromatographic-mass spectrometric assay and HPLC. The distribution and elimination t1/2s of esmolol averaged 2.03 and 9.19 min. The apparent volume of distribution of esmolol averaged 3.43 l/kg and was four times the volume of the central compartment. The total clearance of esmolol averaged 285 ml/min/kg, indicating that nonhepatic routes play a predominant role in its clearance. The t1/2s of formation and elimination of the metabolite averaged 2.82 min and 3.72 hr. The ratio of the metabolite formation and elimination rate constants of the parent drug (kf/k10) averaged 0.829, suggesting that 82.9% of esmolol was converted to the metabolite (which is consistent with the urinary recovery of 71% of the dose as unconjugated metabolite). The volume of distribution and total clearance of the metabolite averaged 0.411 l/kg and 1.28 ml/min/kg. Esmolol was followed by a significant reduction of isoproterenol-induced increase in heart rate and systolic blood pressure at doses of 50, 150, and 400 micrograms/kg/min.(ABSTRACT TRUNCATED AT 250 WORDS)

Reconstructing NMR images from projections under inhomogeneous magnetic field and non-linear field gradients

Both inhomogeneity in the main magnetic field and non-linearity in the gradient fields introduce errors in NMR images reconstructed from projections. It is found that the image artefacts caused by these two sources are separable. The inhomogeneous main field blurs the image while the nonlinear gradients distort the image. Firstly, blurring is removed by reconstructing the image curvilinearly in a coordinate system defined by the gradient fields. The distortions in the image are then corrected by taking an inverse coordinate transformation from the gradient-field coordinates to the spatial coordinates. Experiments performed by computer simulations are presented to demonstrate that, for the first time, accurate images can be obtained under large inhomogeneity and non-linearity in the fields. Mathematical derivations and computational techniques are also described and discussed.

Age-related pharmacokinetics of N-acetylprocainamide in rats

The pharmacokinetics of N-acetylprocainamide, administered orally or intravenously, were studied in 3-, 6-, and 12-month-old rats using a two-way crossover study design. At 3, 6, and 12 months of age, the half-life values of N-acetylprocainamide were 1.66, 1.82, and 2.29 hr, respectively; the apparent volumes of distribution were 4.75, 3.35, and 1.98 liter/kg, respectively. The elimination rate constant, clearance, and absolute bioavailability of the drug (determined by AUC measurements and the amounts excreted unchanged in the urine) decreased significantly with age. The rate of absorption remained unchanged. The amounts of N-acetylprocainamide in the liver and kidneys were significantly higher in the 12-month-old animals. These results clearly demonstrate a significant alteration with age in the bioavailability, distribution, and elimination of N-acetylprocainamide in rats. In long-term toxicity studies of this and other drugs that show age-dependent pharmacokinetics, an adjustment in the chronically administered dose is essential.

Esmolol: a pharmacokinetic profile of a new cardioselective beta-blocking agent

beta-Adrenergic blocking agents--esmolol hydrochloride, pharmacokinetic profile, metabolism. Pharmacokinetic profile--cardioselective beta-adrenergic blocking agent, methyl 3-[4-(2-hydroxy-3-(isopropylamino)propoxy]phenylpropionate hydrochloride. Esmolol--cardioselective beta-adrenergic blocking agent, pharmacokinetic profile.

Tissue distribution of [14C]bretylium tosylate in rats

The distribution of [14C]bretylium tosylate in the body and the relationship between tissue and plasma concentrations was determined following intravenous administration of the drug to Charles River rats. The renal excretion of bretylium was rapid in rats and follows an active process. On the average, 50% of the administered dose was excreted in the urine within 1 hr. In the postequilibrium phase, the plasma concentration declined with a half-life of 5 hr. Bretylium concentrations in all tissues, except the heart, declined rapidly according to a triexponential equation. The liver and kidney bretylium concentrations declined in parallel to the plasma concentration with mean tissue-plasma concentration ratios of 6.04 and 12.3, respectively, in the beta phase. However, the concentration of bretylium in the heart increased gradually and peaked at 2 hr, with a tissue-plasma concentration ratio of 121, which, in turn, declined to a value of greater than 60 after 8 hr. The data indicated that (a) bretylium is rapidly distributed into the liver and kidney immediately after reaching the systemic circulation; (b) the distribution into the heart occurs at a slower rate compared with the other organs, and the drug has a high affinity to the myocardium; and (c) since the heart is the site of action and there is no direct correlation between the concentrations in myocardium and plasma, the antiarrhythmic effect of bretylium may not be related to the plasma concentration.

Pharmacokinetics of hydroxyethyl starch in normal subjects

To determine the elimination of high-molecular-weight hydroxyethyl starch (HES, Mw 450,000) in normal subjects, ten volunteers were given 500 ml 6% HES solution by intravenous infusion, and serial blood and urine samples were collected for nonglucose total carbohydrate determination. On the average, 46 and 64 per cent of the dose was excreted in the urine within two and eight days, respectively. The plasma concentration declined rapidly during the first week after infusion. The average terminal half-life was 17 days during the first 42 days, which accounted for elimination of about 90 per cent of the dose. The remainder was eliminated with a terminal half-life of 48 days determined between days 42 and 83 of the study. As expected, the infusion of HES resulted in plasma volume expansion over a 48-hour period during which time levels of nonglucose carbohydrates were above 3.5 mg/ml. HES is metabolized by alpha-amylase in the body. During the first 48 hours after infusion of HES, plasma alpha-amylase activity was significantly increased over control. Concomitantly, alpha-amylase activity in urine was also elevated but not significantly so.