Prolonged delivery of nicotine in rats via nasal administration of proliposomes

In order to achieve a prolonged delivery of nicotine to the systemic circulation, proliposomes containing nicotine base (NB-proliposomes) or nicotine hydrogen tartarate salt (NS-proliposomes) and a mixture of powdered nicotine hydrogen tartarate salt and sorbitol (1:9 mixture, MP) were administered intranasally to rats at a nicotine dose of 1 mg/kg. Proliposomes, lipid-sorbitol mixtures that form liposomes upon contact with water, were prepared according to previously established methods, and the mixture (MP) was prepared by mixing NS powder with sorbitol particles (105-350 micrometer in size). Nasal absorption of nicotine from these formulations was very rapid (i.e. less than 10 min was required to reach plasma peaks) and showed substantially sustained plasma nicotine levels compared to saline solutions of NB and NS, and previously reported nasal nicotine sprays. The AUC values from the proliposomes and MP were comparable to those from the saline solutions of NB and NS. However, the mean residence time (MRT) and plasma half-life (T(1/2beta)) of nicotine in the present study were much larger than those from the saline solutions. Thus, a prolonged delivery of nicotine to systemic circulation via the application of proliposomes or MP intranasally appears feasible. NB-proliposomes exhibited the best characteristics in terms of the area under the plasma concentration (AUC), MRT and T(1/2beta) of nicotine, which was followed by NS-proliposomes and MP. Retarded conversion of proliposomes and MP to liposomal emulsions and solution in the nasal cavity seems responsible, in part, for the sustained plasma nicotine concentrations, since the emulsions and solution yielded very short MRT and T(1/2beta) of nicotine. In addition, reduced metabolism to cotinine from the proliposomes and MP was apparently responsible for the sustained plasma nicotine levels. These dosage forms of nicotine appear to circumvent some of the shortcomings of transdermal patches (i.e. long T(max)) and nasal sprays (i.e. short T(1/2beta) and physicochemical instability).

Nasal cycle in patients with septal deviation: evaluation by acoustic rhinometry

The nasal cycle in patients with septal deviation was studied by acoustic rhinometric techniques. This study included 24 patients with anteriorly located septal deviations (mean age = 23.5), and 26 normal controls (mean age = 24.7). Data of MCA (minimum cross-sectional area) and NV (nasal volume), collected in 20-minute intervals, were plotted for each subject during 8 hours. Twenty of 24 patients (83%) with septal deviation and 20 of 26 normal subjects (77%) showed at least one complete cycle. Duration of the nasal cycle, which ranged from 100 minutes to 400 minutes, had no statistical difference between the septal deviation group (mean duration of 216 minutes) and the normal control group (mean duration of 227 minutes). The degrees of variation of MCA and NV, defined as Degree of Variation of MCA (%) = 100 (MCAmax - MCAmin)/MCAmax, Degree of Variation of NV (%) = 100 (NVmax - NVmin)/NVmax, which represent the percent change of MCA and NV throughout the study, showed no difference between the wide side and the narrow side, or between the septal deviation group and the normal control group. These findings suggest that the nasal cycle is relatively independent of peripheral anatomic factors for its generation. However, the amplitude of changes of MCA was greater in the wide side, and the sum of both MCAs tended to fluctuate in accordance with the fluctuation of MCA of the wide side. Thus, the nasal cycle seemed to be affected by septal deviation.

Cell death-associated translocation of plasma membrane components induced by CTL

In the very early stages of target cell apoptosis induced by CTL, we found that fluorescence of labeling probes of the target plasma membrane, such as N-(3-triethylammoniumpropyl)-4-(p-dibutylaminostyryl)pyridin ium dibromide (FM1-43), was translocated into intracellular membrane structures including nuclear envelope and mitochondria. This translocation was associated with the execution of CTL-mediated killing, because neither the CTL-target conjugation alone nor the binding of noncytotoxic Th2 clone with target cell was sufficient to provoke the process. Although FM1-43 translocation was observed in perforin-mediated cytotoxicity, examinations with several other dyes failed to detect the evidence for membrane damages that may cause influx of the dye. Moreover, the translocation was also observed in Fas-dependent apoptosis. These data indicate that the translocation precedes the damage of plasma membrane and intracellular organella in the course of apoptotic cell death and may represent the existence of a membrane trafficking that mediates the translocation of plasma membrane components in the early onset of apoptotic cell death.

Nerve sprouting and sudden cardiac death

The factors that contribute to the occurrence of sudden cardiac death (SCD) in patients with chronic myocardial infarction (MI) are not entirely clear. The present study tests the hypothesis that augmented sympathetic nerve regeneration (nerve sprouting) increases the probability of ventricular tachycardia (VT), ventricular fibrillation (VF), and SCD in chronic MI. In dogs with MI and complete atrioventricular (AV) block, we induced cardiac sympathetic nerve sprouting by infusing nerve growth factor (NGF) to the left stellate ganglion (experimental group, n=9). Another 6 dogs with MI and complete AV block but without NGF infusion served as controls (n=6). Immunocytochemical staining revealed a greater magnitude of sympathetic nerve sprouting in the experimental group than in the control group. After MI, all dogs showed spontaneous VT that persisted for 5.8+/-2.0 days (phase 1 VT). Spontaneous VT reappeared 13.1+/-6.0 days after surgery (phase 2 VT). The frequency of phase 2 VT was 10-fold higher in the experimental group (2.0+/-2.0/d) than in the control group (0.2+/-0.2/d, P<0.05). Four dogs in the experimental group but none in the control group died suddenly of spontaneous VF. We conclude that MI results in sympathetic nerve sprouting. NGF infusion to the left stellate ganglion in dogs with chronic MI and AV block augments sympathetic nerve sprouting and creates a high-yield model of spontaneous VT, VF, and SCD. The magnitude of sympathetic nerve sprouting may be an important determinant of SCD in chronic MI.

Reducing noise pollution in the hospital setting by establishing a department of sound: a survey of recent research on the effects of noise and music in health care

A proposal for a solution to reduce stress and anxiety in the hospital setting by combining the problems of excess noise in a hospital setting with the efficacy of music therapy is supported through an analysis of research in the field of noise, hospital noise pollution, and music medicine. Included in this overview are articles describing the effects of noise on health, the problems of noise pollution in the health care setting, and the benefits of replacing noise with music to reduce heart rate, blood pressure, breathing rate, emotional anxiety, and pain. By combining these areas of research, the authors propose the establishment of a department assigned to (1) control the amount of noise in a hospital and (2) provide a center of music therapy for all individuals in the hospital setting, including in-patients, out-patients, doctors, and staff. Due to the large specificity of these areas, this unifying source, or "Department of Sound," is suggested to aid in thoroughly addressing and combining these two concepts most effectively.

Heisenberg, langevin, and current equations via the recurrence relations approach

Some years ago the Heisenberg equation of motion was formally solved by the recurrence relations approach. It is shown here that the Langevin equation represents a structural property of the recurrence relations. The Langevin equation is useful for studying the time evolution of the current. The resulting current-current correlation function is compared with Luttinger's phenomenological theory. Geometric interpretations are made for the conductivity and the dielectric function.

Microsomal triglyceride transfer protein expression during mouse development

Feto-maternal transfer of lipophilic nutrients is an important factor in the normal development of the fetus and may be mediated by lipoproteins as carriers of these nutrients. Two proteins that may be important in this process are apolipoprotein B (apoB, the major structural protein of secreted lipoproteins) and microsomal triglyceride transfer protein (MTP) whose normal activity is required for the secretion of apoB-containing lipoproteins. Although no abnormalities of conception and embryonic lethality are known in humans who inherit genetic deficiencies of either of these proteins, homozygous mice bearing knockouts of either apoB or MTP show early embryonic lethality. To characterize the ontogeny of MTP expression during embryonic mouse development, we have used in situ hybridization to characterize the pattern of expression. By using microwave heating of tissue sections to optimize hybridization, we show that there is robust MTP expression in the yolk sac tissues followed by expression in the primordial liver cell nests as early as day 9 post-coitum (E9.5). Intestinal expression is detected around E12.5 and attains full adult expression patterns by E14.5. No expression in any other tissues was observed, including developing heart, kidney, placenta, and maternal decidua. Thus the pattern of MTP expression is compatible with a role in the transfer of lipophilic nutrients from the yolk sac, prior to hepatic development and to the liver, once the circulatory system has been established.

In vivo rapid reduction of alloantigen-activated CD8+ mature cytotoxic T cells by inhibitors of acidification of intracellular organelles, prodigiosin 25-C and concanamycin B

Prodigiosin (PrG) 25-C and concanamycin B (CMB) are immunosuppressants that specifically inhibit the induction of cytotoxic T cells (CTL) without affecting the function of B cells and helper T cells in vivo. Both compounds inhibit acidification of intracellular organelles and induce destruction of cytotoxic granules and degradation of perforin in vitro. Here we show that a single intraperitoneal (i.p.) injection of PrG 25-C, and of CMB, into mice eliminates cytotoxic activity 7 days after alloantigen stimulation (when mature CTL activity has been detected in control mice), with minimal effect on the alloantigen-specific antibody titre in serum. FK506 did not suppress the cytotoxic activity with this administration schedule. Suppression was accompanied by a decrease in the CD8+ population and in perforin expression of spleen cells induced by alloantigen stimulation. The suppression of CTL activity and decrease in CD8+ cell number was detected as early as 7 hr after the injection of compounds. These results suggest that inhibitors of acidification of intracellular organelles suppress CTL activity in vivo by reducing the number of mature CD8+ CTL.

Decreased oral bioavailability of loxoprofen at second administration in human subjects

The objective of this study was to determine the extent of period effect on the pharmacokineitcs of loxoprofen during consecutive dosing. Loxipen and Loxonin tablets were administered to 16 healthy Korean male subjects at a single dose of 60 mg as loxoprofen sodium anhydrous in a 2 x 2 crossover investigation with a two-week wash-out phase. Concentrations of loxoprofen in plasma were measured by HPLC method for 6 h. The two formulations were found bioequivalent, but analysis of variance (ANOVA) indicated that there was a significant (p < 0.05) period effect in AUCinf (area under the plasma concentration-time curve from time zero to infinity) between the administrations. A 20% decrease in the AUC was seen at the second administration. This period effect on pharmacokinetics of loxoprofen may be relevant for the patients who need consecutive administration of the drug.

TCR internalization induced by peptide/MHC ligands requires the transmembrane domains of alphabeta chains of TCR, but not the expression of CD8 and Thy-1 molecules

T-cell receptor (TCR) internalization occurs via TCR recognition of the peptide/MHC molecule complex on antigen presenting cell (APC). In this study, the requirements for inducing the internalization of TCR molecules on Ld major histocompatibility complex (MHC) class I-restricted T-cells were investigated with 2C cytotoxic T-lymphocyte (CTL) clones with defined peptides as the antigen. To evaluate the function of the transmembrane region of TCR alphabeta chains in TCR internalization, we generated T-cell transfectants expressing the wild type and glycosylphosphatidyl inositol (GPI)-linked form of 2C TCR. Among all peptides forming proper ligands to 2C TCR, only the Qp2Ca peptide induced TCR internalization, which was known to have the highest affinity to both Ld MHC class I molecules and TCR in association with Ld molecules. Such TCR internalization was not observed in cells expressing the GPI-linked form of 2C TCR. Furthermore, the expression of CD8 coreceptor and Thy-1 accessory molecules were both not required for Qp2Ca-induced TCR internalization, and these molecules did not accompany TCR internalization. Altogether, these results suggest that TCR internalization on CTL is not a prerequisite for CTL function.

Spider mite allergy in apple-cultivating farmers: European red mite (Panonychus ulmi) and two-spotted spider mite (Tetranychus urticae) may be important allergens in the development of work-related asthma and rhinitis symptoms

BACKGROUND

Recent investigations have suggested that the citrus red mite (Panonychus citri) is the most important allergen affecting citrus-cultivating farmers with asthma, allergic rhinitis, or both.

OBJECTIVE

We sought to evaluate type I hypersensitivity to spider mites, particularly the European red mite (Panonychus ulmi) and the two-spotted spider mite (Tetranychus urticae), and to determine the relationship between hypersensitivity to spider mites and respiratory dysfunction.

METHODS

We performed a cross-sectional survey. Questionnaires were given, and skin prick tests for 11 inhalant allergens common in Korea and 2 species of spider mites (European red mite and two-spotted spider mite) were performed in 725 apple-cultivating farmers in Korea.

RESULTS

Results of skin prick tests in the apple farmers indicated that European red mite (23.2%) was the most common sensitizing allergen, followed by Tyrophagus putrescentiae (21.2%), two-spotted spider mite (16.6%), Dermatophagoides farinae (16.3%), D pteronyssinus (14.4%), cockroach (13.1%), and Hop Japanese (Humulus Japonicus) pollen (12.0%). Positive skin responses (mean wheal size >/=3 mm) to one or more of 13 inhalant allergens were found in 48.2% of farmers tested, whereas 40 subjects (8.6%) had an isolated skin response to the spider mites. Among 119 farmers with work-related asthmatic symptoms, the positive skin response rates to European red mite and two-spotted spider mite were 40.4% and 27.0%, respectively. These figures were significantly higher than those found among farmers without work-related symptoms (19.1% and 14.1%, respectively; P <.01). The prevalence of work-related asthma symptoms was higher in farmers with positive skin responses to spider mites than in those with negative skin responses to spider mites and those with positive skin responses to any allergen tested (31.4% vs 15.0% vs 21.0%, respectively; P <.05).

CONCLUSION

Spider mites, particularly European red mite and 2-spotted spider mite, are common sensitizing allergens in apple-cultivating farmers. These spider mites may be important causative allergens in the development of work-related respiratory symptoms in these workers.

Pharmacokinetic study of paeoniflorin in mice after oral administration of Paeoniae radix extract

Quantification of paeoniflorin, the principal bioactive component of Paeoniae radix, in mice plasma following oral administration of Paeoniae radix extract was achieved by using a simple and rapid high-performance liquid chromatographic method. The calibration curve for paeoniflorin was linear (r2 = 0.998) over the concentration range 10-200 ng/ml. The coefficients of variation of intra- and inter-day assays were 15.04, 7.31, 6.14, 6.55, 6.63% and 12.71, 6.07, 3.61, 5.51, 4.52% at concentrations of 10, 60, 100, 160, 200 ng/ml, respectively. The recoveries of paeoniflorin from mice plasma were found to be 74.49, 76.83, 80.38 and 80.56% for concentrations of 30, 80, 120 and 160 ng/ml, respectively. The plasma concentration-time curves were fitted with mean terminal half-lives (t(1/2)) of 94.16 min.

Decline in spontaneous activity of group Aalphabeta sensory afferents after sciatic nerve axotomy in rat

Changes are observed in the strength of central synaptic transmission and the firing behavior of primary afferents damaged by peripheral nerve injury. To clarify the relationship between synaptic strength and amount of spontaneous activity, firing behavior was studied in adult, male Sprague-Dawley rats in which sciatic nerve afferents were axotomized. Intra-axonal recordings were taken from Aalphabeta afferents within 7 h (acute, n = 309), at 3 days (n = 228), or at 10 days (n = 230) after sciatic nerve cut. The proportion of spontaneously discharging afferents fell from 22% in the acute group to < or = 13% in chronic groups. Thus, neither the progressive decline in the strength of central synaptic transmission from cut primary afferents nor the altered sensation observed after nerve cut can be explained by chronic changes in spontaneous activity of cut Aalpha/Abeta afferents.

Phase II clinical trial of SKI-2053R, a new platinum analog, in the treatment of patients with advanced gastric adenocarcinoma

BACKGROUND

SKI-2053R (SK Chemicals, Kyungki-Do, South Korea) is a new platinum derivative with antitumor activity against various cell lines, including cisplatin-resistant tumor cell lines. Preclinical studies have suggested that it is less nephrotoxic than cisplatin. This study evaluated the efficacy and toxicity of SKI-2053R in the treatment of patients with advanced gastric adenocarcinoma.

METHODS

Thirty-seven patients with advanced gastric adenocarcinoma that was unresectable or metastatic were treated. No prior chemotherapy or radiotherapy was allowed. Patients received SKI-2053R 360 mg/m(2) by 1-hour infusion on Day 1. After the first cycle, subsequent doses were adjusted according to the toxicity. Courses were repeated every 28 days.

RESULTS

Thirty-five patients were evaluable for response and toxicity. Six patients achieved a major response (17%; 95% confidence interval, 8-33%); 2 were complete and 4 were partial responses. The median duration of response was 7.2 months, with a range of 1-20 months. Patients could tolerate the treatment without significant toxicity. No patients had Grade 3 or 4 toxicity. The most frequent toxicity was Grade 1 or 2 proteinuria (26% of cycles), but it was mild and transient. Leukopenia, thrombocytopenia, azotemia, nausea and vomiting, and neurotoxicity were not frequent. These low toxicity profiles indicated that the dose of SKI-2053R could be increased in future studies.

CONCLUSIONS

SKI-2053R was active in the treatment of patients with gastric adenocarcinoma and had favorable toxicity profiles.

Analysis of F factor TraD membrane topology by use of gene fusions and trypsin-sensitive insertions

This report describes a procedure for characterizing membrane protein topology which combines the analysis of reporter protein hybrids and trypsin-sensitive 31-amino-acid insertions generated by using transposons ISphoA/in and ISlacZ/in. Studies of the F factor TraD protein imply that the protein takes on a structure with two membrane-spanning sequences and amino and carboxyl termini facing the cytoplasm. It was possible to assign the subcellular location of one region for which the behavior of fused reporter proteins was ambiguous, based on the trypsin cleavage behavior of a 31-residue insertion.

Role of papillary muscle in the generation and maintenance of reentry during ventricular tachycardia and fibrillation in isolated swine right ventricle

BACKGROUND

The role of papillary muscle (PM) in the generation and maintenance of reentry is unclear.

METHODS AND RESULTS

Computerized mapping (477 bipolar electrodes, 1.6-mm resolution) was performed in fibrillating right ventricles (RVs) of swine in vitro. During ventricular fibrillation (VF), reentrant wave fronts often transiently anchored to the PM. Tissue mass reduction was then performed in 10 RVs until VF converted to ventricular tachycardia (VT). In an additional 6 RVs, procainamide infusion converted VF to VT. Maps showed that 77% (34 of 44) of all VT episodes were associated with a single reentrant wave front anchored to the PM. Purkinje fiber potentials preceded the local myocardial activation, and these potentials were recorded mostly around the PM. When PM was trimmed to the level of endocardium (n = 4), sustained VT was no longer inducible. Transmembrane potential recordings (n = 5) at the PM revealed full action potential during pacing, without evidence of ischemia. Computer simulation studies confirmed the role of PM as a spiral wave anchoring site that stabilized wave conduction.

CONCLUSIONS

We conclude that PM is important in the generation and maintenance of reentry during VT and VF.

Characterization of Enterococcus faecalis alkaline phosphatase and use in identifying Streptococcus agalactiae secreted proteins

We have identified and characterized an Enterococcus faecalis alkaline phosphatase (AP, encoded by phoZ). The predicted gene product shows homology with alkaline phosphatases from a variety of species; it has especially high similarity with two alkaline phosphatases from Bacillus subtilis. Expression of phoZ in Escherichia coli, E. faecalis, Streptococcus agalactiae (group B streptococcus [GBS]), or Streptococcus pyogenes (group A streptococcus [GAS]) produces a blue-colony phenotype on plates containing a chromogenic substrate, 5-bromo-4-chloro-3-indolylphosphate (XP or BCIP). Two tests were made to determine if the activity of the enzyme is dependent upon the enzyme's subcellular location. First, elimination of the signal sequence reduced AP activity to 3% of the wild-type activity (or less) in three species of gram-positive bacteria. Restoration of export, using the signal sequence from C5a peptidase, restored AP activity to at least 50% of that of the wild type. Second, we engineered two chimeric proteins in which AP was fused to either a periplasmic domain or a cytoplasmic domain of lactose permease (a membrane protein). In E. coli, the periplasmic fusion had 17-fold-higher AP activity than the cytoplasmic fusion. We concluded that AP activity is export dependent. The signal sequence deletion mutant, phoZDeltass, was used to identify random genomic fragments from GBS that encode exported proteins or integral membrane proteins. Included in this set of fragments were genes that exhibited homology with the Rib protein (a cell wall protein from GBS) or with DppB (an integral membrane protein from GAS). AP acts as a reporter enzyme in GBS, GAS, and E. faecalis and is expected to be useful in a variety of gram-positive bacteria.

Citrus red mite (Panonychus citri) is the most common sensitizing allergen of asthma and rhinitis in citrus farmers

OBJECTIVE

To evaluate type I hypersensitivity to citrus red mite (Panonychus citri), its prevalence, and relationship to respiratory dysfunction, a cross-sectional survey was performed among citrus farmers on Cheju Island, Korea.

MATERIALS AND METHODS

Questionnaires, and skin prick test responses to 11 common inhalant allergens and citrus red mite were performed in 181 citrus farmers, and serum-specific IgE antibodies to citrus red mite were measured by ELISA in sera of 123 subjects. To determine airway hyperresponsiveness, methacholine bronchial provocation tests were performed in 55 subjects who complained of recurrent lower respiratory symptoms.

RESULTS

The prevalence of asthma-based on presence of asthmatic symptoms on the questionnaire and airway hyperresponsiveness to methacholine, and allergic rhinitis based on presence of nasal symptoms on the questionnaire and positive skin-test response were 12.1% and 19.3%, respectively. The positive rate of skin responses to one or more of 11 common inhalant allergens excluding citrus red mite was 17.1%, and if citrus red mite was included, 25.9% of farmers had positive responses. On skin prick tests, citrus red mite (16.5%) was the most common sensitizing allergen, followed by cockroach (11.0%), Dermatophagoides pteronyssinus (9.9%), and D. farinae (9.3%). Among farmers with asthma and allergic rhinitis, the positive skin responses to citrus red mite were noted in 54.5 and 68.5%, respectively. Serum-specific IgE antibodies to citrus red mite were detected in 45 farmers (36. 5%) of the 123 tested, and there was significant correlation between specific IgE level and weal (A/H ratio) to citrus red mite (r = 0.57, P < 0.001). The prevalence of asthma was higher in subjects with positive skin responses or high serum-specific IgE antibodies to citrus red mite than in those without skin response or serum specific IgE (P < 0.05, respectively).

CONCLUSION

Citrus red mite is the most important allergen in citrus farmers with asthma and rhinitis in which causative allergen has not been identified. It should be included in the skin test battery for screening the causative allergen in farmers exposed to citrus red mite.

Skin reactivity to inhalant allergens, total serum IgE levels, and bronchial responsiveness to methacholine are increased in parents of nonatopic asthmatic children

BACKGROUND

Family studies suggest that asthma has an increased familial occurrence, but the hypothesis of a genetic predisposition to IgE response and bronchial hyperresponsiveness (BHR) on the expression of nonatopic asthma is controversial.

OBJECTIVE

The aim of this study was to evaluate familial predisposition to IgE response and BHR on expression of nonatopic asthma.

METHODS

One hundred four parents of nonatopic asthmatic children, 154 parents of atopic asthmatic children, 78 parents of atopic nonasthmatic control children, and 80 parents of nonatopic control children provided questionnaire data and underwent allergy skin prick tests with 10 inhalant allergens and methacholine bronchial provocation tests. Total serum IgE levels were determined in 352 parents (134 with atopic asthmatic children, 87 with nonatopic asthmatic children, 65 with atopic control children, and 66 with nonatopic control children).

RESULTS

Prevalence of asthma, based on questionnaire data and on BHR to methacholine, was higher among parents of nonatopic asthmatic children (10.6%) and atopic asthmatic children (9.1%) than among those of nonatopic control children (1.3%). BHR to methacholine was higher among parents of nonatopic asthmatic children (19.2%) and atopic asthmatic children (16.2%) than among those of atopic and nonatopic control children (5.1% and 1.3%, respectively). The percentage of positive skin test responses to 10 inhalant allergens was higher among parents of atopic asthmatic children (43.9%), nonatopic asthmatic children (39.4%), and atopic control children (38.5%) than among those of nonatopic control children (23.7%). Geometric means (IU/mL +/- SEM) of total serum IgE were higher among parents of atopic and nonatopic control children than among those of nonatopic control children (2.11 +/- 0.05 vs 2. 20 +/- 0.06 vs 2.09 +/- 0.07 vs 1.92 +/- 0.06).

CONCLUSION

Nonatopic asthma runs in families. The prevalence of positive skin test responses to inhalant allergens, BHR to methacholine, and total serum IgE levels is higher among the parents of nonatopic and atopic asthmatic children than among those of nonatopic control children.

Evolution and molecular characterization of a beta-globin gene from the Australian Echidna Tachyglossus aculeatus (Monotremata)

Coinciding with a period in evolution when monotremes, marsupials, and eutherians diverged from a common ancestor, a proto-beta-globin gene duplicated, producing the progenitors of mammalian embryonic and adult beta-like globin genes. To determine whether monotremes contain orthologues of these genes and to further investigate the evolutionary relationships of monotremes, marsupials, and eutherians, we have determined the complete DNA sequence of an echidna (Tachyglossus aculeatus) beta-like globin gene. Conceptual translation of the gene and sequence comparisons with eutherian and marsupial beta-like globin genes and echidna adult beta-globin indicate that the gene is adult expressed. Phylogenetic analyses do not clearly resolve the branching pattern of mammalian beta-like globin gene lineages and it is therefore uncertain whether monotremes have orthologues of the embryonic beta-like globin genes of marsupials and eutherians. Four models are proposed that provide a framework for interpreting further studies on the evolution of beta-like globin genes in the context of the evolution of monotremes, marsupials, and eutherians.

Simultaneous GC-MS determination of nicotine and cotinine in plasma for the pharmacokinetic characterization of nicotine in rats

A gas liquid chromatography/mass spectrometry assay method was developed for the simultaneous determination of nicotine and its major metabolite, cotinine, in rat plasma. Of particular interest was improving the low and variable extraction recovery for the parent drug and the metabolite. In addition, the feasibility of this assay method for pharmacokinetic studies of nicotine and cotinine after intravenous (i.v.), oral, and intraperitoneal (i.p.) administration of 1 mg kg(-1) of nicotine was tested. The low (30 and 48% for nicotine and cotinine, respectively) and variable (25 and 22% coefficient of variation for nicotine and cotinine, respectively) extraction recovery for nicotine and cotinine into dichloromethane was significantly improved by the addition of NaCl to the plasma. As a result, the recoveries for nicotine and cotinine were improved to 68 and 65%, respectively. The coefficient of variation was less than 10% in the 50-500 ng ml(-1) range and less than 16.58% at 10 ng ml(-1) for both nicotine and cotinine, indicating that the reproducibility of the assay was also improved by the extraction procedure. When injected intravenously at a dose of 1 mg kg(-1), the temporal profile of plasma concentration for nicotine followed a bi-exponential decline. Moment analysis revealed that pharmacokinetic parameters for nicotine (i.e. Cl, 46.30 ml min(-1) kg(-1); Vss, 2.77 1 kg(-1)) was similar to those reported in studies using 14C-nicotine. Absolute bioavailabilities of nicotine for i.p. and oral administration were 87.0 and 80.4%, respectively. The concentration of the metabolite increased up to 4 h to reach Cmax after i.p. and oral administrations and then declined slowly with time. These results indicate that this convenient analytical procedure is readily applicable to pharmacokinetic studies of nicotine and cotinine involving small laboratory animals with a sensitivity comparable with that reported for studies using 14C-nicotine.

Expression of the recombinant Klebsiella aerogenes UreF protein as a MalE fusion

Expression of the active urease of the enterobacterium, Klebsiella aerogenes, requires the presence of the accessory genes (ureD, ureE, ureF, and ureG) in addition to the three structural genes (ureA, ureB, and ureC). These accessory genes are involved in functional assembly of the nickel-metallocenter for the enzyme. Characterization of ureF gene has been hindered, however, since the UreF protein is produced in only minute amount compared to other urease gene products. In order to overexpress the ureF gene, a recombinant pMAL-UreF plasmid was constructed from which the UreF was produced as a fusion with maltose-binding protein. The MBP-UreF fusion protein was purified by using an amylose-affinity column chromatography followed by an anion exchange column chromatography. Polyclonal antibodies raised against the fusion protein were purified and shown to specifically recognize both MBP and UreF peptides. The UreF protein was shown to be unstable when separated from MBP by digestion with factor Xa.

Increased bioavailability of propranolol in rats by retaining thermally gelling liquid suppositories in the rectum

Mucoadhesive liquid suppositories were prepared by adding mucoadhesive polymers (0.6%) to a formulation of thermally gelling suppositories that contained poloxamer 407 (15%), poloxamer 188 (15%) and propranolol HCl (2%). Hydroxypropylcellulose (HPC), polyvinylpyrrolidone (PVP), carbopol, polycarbophil and sodium alginate were examined as mucoadhesive polymers. The characteristics of the suppositories differed depending on the choice of mucoadhesive polymer. For example, the gelation temperature was between 30 and 36 degrees C, the mucoadhesive force was between 430 and 5800 dyne/cm2, the apparent first-order release rate constant in phosphate buffer, pH 6.8, was between 0.399 and 0.271 h-1, the migration distance of the suppository in the rectum 4 h after administration was between 1 and 5 cm, and the bioavailability of propranolol was between 60.9 and 84.7%. Rectal bioavailability increased as the mucoadhesive force increased (r=0.984, p<0.0005), and the migration distance decreased (r=-0.951, p<0.005). No relationship was found between the bioavailability and the gelation temperature, drug release or irritation of the rectal mucosal membrane by the suppository. Therefore, retaining propranolol at the dosed site in the rectum by the addition of appropriate mucoadhesives to the formulation of liquid suppositories appears to be a very important factor in avoiding first-pass hepatic elimination and thereby increasing the bioavailability of the drug. Among the mucoadhesive polymers examined, sodium alginate and polycarbophil exhibited the largest mucoadhesive force and the smallest intrarectal migration resulting in the largest bioavailability of propranolol (84.7 and 82.3%, respectively). In contrast to other polymers, sodium alginate alone caused no irritation of the rectal mucosal membrane. Thus, poloxamer liquid suppositories containing sodium alginate appears to be a preferred formulation for drugs that are sensitive to extensive first-pass metabolism.

Cation selective channels formed by a C-terminal fragment of beta-amyloid precursor protein

The C-terminal 105 amino acid fragment of beta-amyloid precursor protein (CT105) is highly neurotoxic. To obtain insights into its cytotoxic effect, we examined the ionophoric effects of CT105 (10-1000 nM) on artificial lipid membranes. Macroscopic membrane conductance increased with CT105 concentration and its ionophoric effect was comparable to that of amyloid beta protein. The mean unitary conductance of CT105-induced channels was 120 pS and open-state probability was close to 1 at voltages from -80 to +80 mV. CT105induced channels were selective to cations (PK/ P(Cl) = 10.2), being most selective to Ca2+. These findings suggest that CT105 can cause direct neurotoxic effects by forming Ca2+ permeable cation channels on neuronal membranes.