Hospitalised low-risk community-acquired pneumonia: outcome and potential for cost-savings

Fine et al. from USA have identified a sub-group of patients with community-acquired pneumonia (CAP) with a low risk of mortality and suggested that it may be cost-effective to manage them as outpatients. The aims of this study were: to evaluate the outcome of low risk CAP patients that were hospitalised in our local setting, and to gauge the number of such patients in order to estimate the potential cost-savings by treating them as outpatients, as well as the safety of such an approach. All patients with CAP admitted to our hospital from 1 April 1997 to 1 March 1998 were enrolled into this prospective cohort study. Low-risk patients were identified, and their hospital outcome compared with other patients. Hospitalisation charges were obtained from the Finance Department. There were 226 patients with CAP. The average age was 64 years with a range of 12 to 96 years. The median hospital stay was 6 days. Mortality was 13.7%. 16.8% required admission to the ICU; none of these were low-risk patients. There were 47 (21%) low-risk patients, and there was no mortality in this group. They had significantly shorter hospital stay (6.4 days versus 10 days) and lower hospitalisation charges ($2,160 versus $5,770) compared to other CAP patients. Only one low-risk patient had a positive blood culture. In conclusion, nearly one-fifth of our CAP admissions consisted of low-risk patients that experienced no mortality, and required a significantly shorter hospitalisation. The management of such patients who are young (< or = 50 years), with no serious co-morbidities in an outpatient setting may be a cost-effective strategy, and this group of patients consumed 9% of the total hospitalisation charges for CAP.

High-resolution HLA-A*0201 subtyping using directed heteroduplex analysis

HLA-A02* has become an important target for cytotoxic T lymphocyte-based immunotherapy reflecting the high prevalence of this allele in patient populations. There are at least 26 different A*02 alleles, and their subtype specificity has significant functional implications for T-cell-mediated recognition of immunologic targets. We have developed a novel method for HLA-A*02 allelic screening using directed heteroduplex analysis (DHDA). DNA samples from Epstein-Barr virus (EBV)-transformed B lymphoblastoid cell lines (EBV-B) representing 10 different HLA-A*02 alleles (0201, 0202, 0204, 0205, 0206, 0208, 0210, 0211, 0216, 0217) were prepared. In addition, DNA was prepared from 81 individuals representing a wide variety of A*02 subtypes previously determined by sequence specific primer (SSP) polymerase chain reaction (PCR) including individuals heterozygous for two A*02 specificities. Probes and samples were generated by PCR amplification using HLA-A*02 specific primers encompassing exons 2 and 3, where most of the functionally significant allelic polymorphism is clustered. DHDA was performed by generating heteroduplex molecules composed of a fluorescein-labeled allelic probe sequence and an unlabeled allelic PCR product. Gel retardation was consistent for allele-probe combinations. We were able to identify several A*02 alleles prepared from EBV-B cell lines that, when used as probes, had very impressive specificity and sensitivity. Combinations of two probes were identified (0205 + 0211 and 0208 + 0211) that allowed differentiation of A*0201 alleles from all other A*02 alleles tested. All samples typed by probe combinations had DHDA typing and SSP typing confirmed by DNA sequencing. This study expands the molecular typing repertoire available to the modern HLA laboratory, and shows that DHDA has significant promise as a reliable screening method for HLA A*02 subtyping.

Comparisons of prognostic scoring systems for myelodysplastic syndromes: a Korean multicenter study

We have conducted a multicenter collaborative retrospective analysis to evaluate clinical characteristics and to compare prognostic scoring systems of 149 Korean patients with myelodysplastic syndromes (MDS). The median age of the patients was 53 years (range 17-82 years) with high of the patients being younger than 40 years. Median survival was 22.6 months, and 25 patients (17%) progressed to acute myelogenous leukemia (AML) with a median interval of 6 months (range 1-45 months). Major independent variables assessed by multivariate analysis were FAB subtypes and bone marrow (BM) blast percentages for survival and BM blast percentages for AML transformation. To compare the various scoring systems in the prediction for survival and transformation to AML, FAB, Sanz and Bournemouth scoring systems were applied to all patients, while the international prognostic scoring system (IPSS), Lille and Toyama scoring systems were applied to 91 patients. The Sanz scoring system (P < 0.0001), FAB classification (P < 0.0001), IPSS (P < 0.001), and Toyama scoring system (P < 0.005) were highly predictive for survival showed greater discrimination than that of the other systems. For AML transformation, the IPSS (P < 0.0001), Toyama scoring system (P < 0.0001), FAB classification (P < 0.0001), and Lille scoring system (P < 0.005) successfully discriminated risk groups. Although the prognostic factors and the distribution of age were different from those in Western reports, the IPSS and Toyama scoring system were applicable for predicting survival and leukemic transformation in Korean patients with MDS.

A sensitive fluorescence in situ hybridization technique for detection of porcine reproductive and respiratory syndrome virus

A sensitive fluorescence in situ hybridization (ISH) for detecting porcine reproductive and respiratory syndrome virus (PRRSV) RNA in viral infected tissue was developed using digoxigenin-labeled RNA probes targeted on the nucleocapsid gene of PRRSV. In situ RNA/RNA hybrids were detected with an anti-digoxigenin antibody alkaline phosphatase conjugate and further revealed with Fast Red TR salt/naphthol AS-MX phosphate using a fluorescent microscope. Viral nucleic acid was readily demonstrated within macrophages, known to be the major target of PRRSV. In addition, positively stained cells were found in the salivary gland and skin tissues which have not been reported to contain PRRSV infected cells before. In conclusion, the fluorescence ISH used in this study provides a fast and sensitive means for screening virus-infected tissues in which relatively few cells are affected. This advantage will be especially beneficial for studying viral persistence and for routine diagnosis of PRRSV infection.

Proteomics: theoretical and experimental considerations

Cellular engineering relies on the ability to decipher the genetic basis of various phenotypes. Emerging technologies for analyzing the biological function of the information encoded in the genome of particular organisms and/or tissues focus on the monitoring of transcription (mRNA) and translation (protein) processes. Elementary theoretical considerations presented in this article strongly suggest that a combination of mRNA and protein expression patterns should be simultaneously considered to fully develop a conceptual understanding of the functional architecture of genomes and gene networks. We propose a framework of experimental and mathematical methods for acquiring and analyzing quantitative proteomic information and discuss recent developments in proteome analytical technology.

Acute and chronic phase platelet aggregability studies in Chinese patients after implantation of a permanent transvenous pacemaker

It has been suggested that the incidence of thromboembolic events always increases in patients after insertion of a transvenous pacemaker. Blood samples from twenty consecutive patients (fifteen males and five females) before and after pacemaker implantation was retained for platelet aggregability studies which were analyzed separately with ADP, collagen, epinephrine and arachidonic acid. The maximal amplitude of platelet aggregatory curve was detected by an aggregometer. The samples collected the day before pacemaker implantation (day 0) were used as self-control. Day 1 and day 3 after pacemaker implantation were defined as the acute phase, while day 30 was defined as the chronic phase. The maximal amplitude of platelet aggregatory curve was observed to be lowest on day 1 and then return to normal on day 3 and day 30. The results of platelet aggregability, however, showed no significant difference (P>0.05) between self-control and post-implantation samples. In conclusion, there was no significant change in platelet aggregability for either acute or chronic phases after pacemaker implantation. Antiplatelet medications may not be necessary for the prevention of thromboembolic events after the implantation of a pacemaker.

Oxamflatin is a novel antitumor compound that inhibits mammalian histone deacetylase

Oxamflatin [(2E)-5-[3-[(phenylsufonyl) aminol phenyl]-pent-2-en-4-ynohydroxamic acid] induces transcriptional activation of junD and morphological reversion in various NIH3T3-derived transformed cell lines. We found that oxamflatin showed in vitro antiproliferative activity against various mouse and human tumor cell lines with drastic changes in the cell morphology and in vivo antitumor activity against B16 melanoma. Oxamflatin caused an elongated cell shape with filamentous protrusions as well as arrest of the cell cycle at the G1 phase in HeLa cells. These phenotypic changes of HeLa cells were apparently similar to those by trichostatin A (TSA), a specific inhibitor of histone deacetylase (HDAC). The effect of oxamflatin on the transcriptional activity of the cytomegalovirus (CMV) promoter was examined and compared with known HDAC inhibitors, TSA, sodium n-butyrate, and FR901228. Oxamflatin as well as all these inhibitors greatly enhanced the transcriptional activity of the CMV promoter in a dose-dependent manner. Oxamflatin, like TSA, inhibited intracellular HDAC activity, as a result of which marked amounts of acetylated histone species accumulated. Finally, effects on expression of several endogenous genes involved in cell morphology and cell cycle control in HeLa cells were analysed. Expression of gelsolin, cyclin E and Cdk inhibitors including p21WAF1/Cip1 was highly augmented, while that of cyclin A and cyclin D1 was decreased by oxamflatin. These results suggest that changes in the expression pattern of the genes regulating cell morphology and the cell cycle due to histone hyperacetylation are responsible for the antitumor activity, the morphological change and the cell cycle arrest induced by oxamflatin.

Behçet's disease sera containing antiendothelial cell antibodies promote adhesion of T lymphocytes to cultured human dermal microvascular endothelial cells

Antiendothelial cell antibodies (AECA) have been detected in the sera of patients of autoimmune diseases showing vasculitis. Using IgM-ELISA, we found AECA in 42 (56%) of 75 sera samples from patients with Behçet's disease in a previous study. All of the 15 AECA-positive sera of Behçet's disease patients had an increased expression of the intercellular cell adhesion molecule-1 (ICAM-1), 93.3% of the sera induced the vascular cell adhesion molecule-1 (VCAM-1), and 100% of the serum induced the E-selectin molecule on human dermal microvascular endothelial cells (HDMEC). After stimulation of HDMEC with AECA-positive sera of Behçet's disease patients, the expression of ICAM-1 and VCAM-1 on HDMEC increased significantly at 4 hours, reaching a peak at 16 hours. Expression of E-selectin was induced at 1 hour after stimulation with a peak at 4 hours and it decreased thereafter. Adherence of T lymphocytes to HDMEC increased significantly after stimulation with AECA-positive sera from Behçet's disease patients. Also, the adherence of T lymphocytes to HDMEC increased at 4 hours and returned to its normal level at 48 hours. These results show that AECA-positive sera of Behçet's disease patients are capable of activating HDMEC to promote the adherence of T lymphocytes to increase the expression of ICAM-1, VCAM-1, and E-selectin on the cell surfaces. The whole process may play an important role in the pathogenesis of vasculitis in Behçet's disease.

Phenotyping of flavin-containing monooxygenase using caffeine metabolism and genotyping of FMO3 gene in a Korean population

Flavin-containing monooxygenase (FMO) activity was determined in 82 Korean volunteers by taking molar concentration ratio of theobromine and caffeine present in the 1 h urine (between 4 and 5 h) samples collected after administration of a cup of coffee containing 110 mg of caffeine. Among 82 volunteers, there were 19 women and 63 men (30 smokers and 52 non-smokers). Volunteers were divided into two groups comprising low (0.53-2.99) and high (3.18-11.95) FMO activities separated by an antimode of 3.18. Peripheral bloods were sampled from these volunteers and their genomic DNAs were amplified by polymerase chain reaction with oligonucleotides designed from intronic sequences of human FMO3 gene. Comparing nucleotide sequences of the amplified FMO3 gene originating from randomly selected individuals with low and high FMO activities, nine point mutations were identified in the open reading frame sequences. Among these nine mutations, three FMO3 mutant types (FMO3/Stop148, Lys158 and Gly308) were selected and correlated with FMO activities observed in our Korean population. A rare FMO3/Stop148 mutant allele originating from FMO3/Gly148 occurred by substitution of G442T in exon 4 and yielded a premature TGA stop codon. The stop codon was detected in one individual having the second lowest FMO activity and he had the mutation in heterozygous state. In a pedigree study, he was found to have inherited the mutation from his mother who also had a heterozygous stop codon and equally low FMO activity. In our volunteers, two other common mutations were detected in exons 4 and 7. The one in exon 4 resulted from a G472A change eliminating a HinfI restriction site and produced an amino acid substitution from Glu158 to Lys. The other mutation in exon 7 resulted from an A923G change generating a DraII restriction site and produced a non-conservative replacement of Glu308 to Gly. Based on the secondary structure maps of FMO3 enzyme proteins for these two mutant types, FMO3/Gly308 mutation transformed the helix structure into a sheet shape and indicated that dysfunctional FMO3 may be produced. FMO3/Lys158 mutation did not alter the secondary structure. Approximately 80% of volunteers with homozygous and/or heterozygous mutations on either one or two of these mutations had low FMO activities. Thus, individuals with these FMO3 gene mutations may have defective metabolic activity for many clinically used drugs and dietary plant alkaloids which are oxidized primarily by hepatic FMO3.

Generation of HLA-DP transgenic pigs for the study of xenotransplantation

The shortage of human organs has prompted scientists to seek xenogeneic sources of donors. To date, DAF, MCP, and CD59 transgenic pigs have been generated to inhibit hyperacute rejection. However, besides hyperacute rejection, acute and chronic rejection must also be considered in the use of porcine organs for xenotransplantation. The role of HLA-II in transgenic xeno-organ transplantation remains to be elucidated. By microinjecting 1655 embryos, we have generated one stillborn HLA-DR and two live HLA-DP transgenic pigs: P113-7 (male, carrying one copy of exogene) and P113-8 (female, carrying 2-3 copies of exogenes). The gene status of the live transgenic pigs was confirmed by PCR, Southern blot, and PCR product sequencing analysis. The expression of transgenes in these transgenic pigs were confirmed by RT-PCR analysis and immunohistochemical staining of frozen sections of ear tissue.

Proteome analysis of factor for inversion stimulation (Fis) overproduction in Escherichia coli

The factor-for-inversion stimulation protein (Fis) is a global regulatory protein in Escherichia coli that activates ribosomal RNA (rRNA) transcription by binding to three upstream activation sites of the rRNA promoter and enhances transcription 5- to 10-fold in vivo. Fis overexpression results in different effects on cell growth depending on nutrient conditions. Differential proteome analysis of Fis-expressing cells shows ten protein spots corresponding to Fis overexpression in both rich (YT) and minimal (M9+glucose) media. Three of these spots have been identified as elongation factor TS, histidine-binding periplasmic protein precursor, and ketol-acid reductoisomerase.

Prognostic value of DNA flow cytometry in stomach cancer: a 5-year prospective study

The role of DNA flow cytometry in the prediction of prognosis for patients with stomach cancer remains to be defined. Thus we studied prospectively the role of DNA flow cytometry as a prognosis indicator in stomach cancer patients in a high-incidence area. Between November 1990 and December 1992, primary stomach cancer tissues were obtained from the surgical specimens from 217 patients (148 male, 69 female). DNA flow cytometric analyses of DNA ploidy and S-phase fraction were performed and the results were correlated with patient survival. The median age of the patients was 55 years (range 24-78). Aneuploid cell population was found in 114 of 217 samples (53%). Tumour S-phase fraction was obtained in 96 of 103 diploid tumours (93%) and 61 of 114 aneuploid tumours (54%). After median follow-up of 66.1 months, the patients with tumours with an S-phase fraction over 17% had significantly worse survival rates than patients with tumours with S-phase fractions of lower than 8% or 8-17% (45% vs 59% and 63% of patients surviving, P = 0.007). Tumour ploidy status did not correlate with patient survival. Multivariate analyses showed that the TNM stage remained the most important prognostic indicator. The tumour S-phase fraction was also an independent prognostic indicator (relative risk 2.300, 95% CI, 1.252-4.223). Tumour S-phase fraction obtained by DNA flow cytometry is an independent prognostic indicator for the survival of the patients with stomach cancer.

Rapid and sensitive determination of paclitaxel in mouse plasma by high-performance liquid chromatography

This report describes a rapid, simple and sensitive isocratic high-performance liquid chromatography with diode array UV detection for micro-sample analysis of paclitaxel in mouse plasma. The analysis utilized a Capcell-pak octadecyl analytical column and a mobile phase consisting of acetonitrile--0.1% phosphoric acid in deionized water (55:45, v/v). Paclitaxel and n-hexyl p-hydroxybenzoic acid (internal standard) were extracted from plasma by one-step extraction with tert.-butyl methyl ether. Peak purity was determined over a UV wavelength range of 200 to 400 nm. Paclitaxel and the internal standard were eluted at 3.4 min and 5.4 min, respectively, at a mobile phase flow-rate of 1.3 ml/min. No interfering peaks were observed and the total run time was 10 min. The standard curve was linear (r = 0.9999) over the concentration range of 0.010-500 micrograms/ml. The extraction recovery was > 90% for both paclitaxel and n-hexyl p-hydroxybenzoic acid. The intra- and inter-day assay variabilities of paclitaxel ranged from 0.4 to 2.2% and 0.6 to 7.8%, respectively. The LOD and LOQ were 5 and 10 ng/ml, respectively, for paclitaxel using a plasma sample volume of 100 microliters. This highly sensitive and simple assay method was successfully applied to a pharmacokinetic study after i.v. administration of paclitaxel 20 mg/kg to mice.

Antitumor agents 187: synthesis and cytotoxicity of substituted 8,8-dimethyl-2H,8H-pyrano[6,5-h]quinoline-2-one and related compounds

Several substituted 8,8-dimethyl-2H,8H-pyrano[6,5-h]quinoline-2-ones and related compounds were synthesized and evaluated for their in vitro cytotoxicity against a panel of human tumor cell lines. The most active compound (3) showed significant cytotoxic activity with GI50 values in the micromolar range.

Recent advances in the discovery and development of quinolones and analogs as antitumor agents

Compounds that interact with DNA or microtubules by multiple mechanisms and cause diverse cytotoxic lesions are potential targets for anticancer drug development. Accordingly, a relatively new approach to the rational design of antitumor agents is based on the quinolone class of antibacterials. Their mechanism of antibacterial action involves inhibition of DNA gyrase, and numerous new quinolones do exhibit antitumor activity. Thus, these new quinolone structures display a novel mode of action for the quinolone class as antitumor agents. The potential for quinolones to be used as topoisomerase II inhibitors, as well as antimitotic agents, is reviewed with a focus on recent discoveries and development of antitumor quinolones, especially related work in the author's laboratory.

Rabbits treated with chronic isepamicin are resistant to mivacurium and rocuronium

We compared the dose-response relationships and the neuromuscular blocking effects of mivacurium and rocuronium after chronic isepamicin therapy for 7 days in 56 anesthetized rabbits. Train-of-four stimuli were applied every 10 s to the common peroneal nerve, and the force of contraction of the tibialis anterior muscle was measured. Chronic isepamicin therapy is associated with a rightward shift of the mivacurium and rocuronium dose-response curves. The effective dose for 50% twitch depression of mivacurium and rocuronium increased significantly, from 16.9 +/- 4.8 and 56.5 +/- 5.3 microg/kg, respectively, with placebo to 30.6 +/- 5.3 and 75.6 +/- 4.7 microg/kg, respectively, during isepamicin therapy. The isepamicin rabbits receiving mivacurium 0.18 mg/kg or rocuronium 0.6 mg/kg had an accelerated recovery from neuromuscular blockade compared with those receiving placebo. The results of this study show that mivacurium and rocuronium have both a decreased effect and a shorter duration of action in rabbits when used during concurrent isepamicin therapy.

IMPLICATIONS

We studied the dose-response relationships and the neuromuscular blocking effects of mivacurium and rocuronium during chronic isepamicin therapy in rabbits. Mivacurium and rocuronium have both a decreased effect and a shorter duration of action during chronic aminoglycoside antibiotic therapy in rabbits.

Frequency of spinocerebellar ataxia types 1,2,3,6,7 and dentatorubral pallidoluysian atrophy mutations in Korean patients with spinocerebellar ataxia

Autosomal dominant cerebellar ataxias (ADCAs) are a heterogeneous group of disorders characterized by degenerative symptoms in the cerebellum, spinal cord, and brain stem. Six different genes have been reported to be associated with ADCA, and the length of trinucleotide repeats of these genes is correlated with the age at onset and severity of symptoms. Although there are strong hereditary effects in these disorders, most of the studies carried out in heterogeneous populations and in small groups obscure the true incidence of these diseases. We examined the frequency of six types of ADCAs in 87 unrelated Korean patients with progressive ataxia and compared the results to the frequencies in other ethnic groups. Spinocerebellar ataxia (SCA) type 2 was the most frequent hereditary ataxia (12.6%) and types 3 and 6 accounted for 4.6% and 6.9% of ataxia patients, respectively. Dentatorubral pallidoluysian atrophy was also found in three patients (3.4%). No instances of SCA types 1 or 7 were detected. These findings show the striking contrast to the white population and a difference from Japanese findings. Our results demonstrate that dentatorubral pallidoluysian atrophy should be included in the differential diagnosis of Korean patients with spinocerebellar ataxia, and that there are strong hereditary effects in patients with ADCAs.

Insulin-like growth factor-I (IGF-I) ameliorates and IGF binding protein-1 (IGFBP-1) exacerbates the effects of undernutrition on brain growth during early postnatal life: studies in IGF-I and IGFBP-1 transgenic mice

Insulin-like growth factor-I (IGF-I) plays an important role in the stimulation of postnatal brain growth. In transgenic (Tg) mice, IGF-I overexpression stimulates postnatal brain growth, whereas decreased IGF-I availability caused by ectopic brain expression of IGF binding protein-1 [(IGFBP-1), an inhibitor of IGF-I action] retards postnatal brain growth. Because undernutrition during early postnatal development profoundly retards growth and maturation of the brain in rodents, we sought to determine the influence of IGF-I on undernutrition-induced brain growth retardation. Caloric restriction was imposed on IGF-I Tg mice, IGFBP-1 Tg mice, and their non-Tg littermates by separating half of each litter from their dams during the suckling period, postnatal d 1 to 21. Undernutrition reduced the brain growth of each group of mice, but the growth of undernourished IGF-I Tg mice was comparable to that of well-fed control mice (increased 4.13- and 4.22-fold, respectively) and greater than that of undernourished control mice (increased 3.45-fold), whereas undernourished IGFBP-1 Tg mice exhibited less growth (increased 3.15-fold) than undernourished control mice. When the effects of undernutrition were examined in specific brain regions of each group, the same pattern was observed, and IGF-I was found to be more effective in preserving the growth of the regions with the highest transgene expression (cerebral cortex, hippocampus, and diencephalon). Despite undernutrition, IGF-I transgene expression stimulated overgrowth of these regions as well as that of the posterior medial barrel subfield, a somatosensory area of the cerebral cortex in which IGF-I may be especially important in development. These data indicate that IGF-I can ameliorate the brain growth retardation caused by undernutrition imposed during development, although it is unclear whether IGF-I directly opposes the impact of undernutrition or acts independently of nutritional status. Nonetheless, these findings raise the possibility that the relatively high IGF-I expression during early postnatal life may be responsible for sparing the brain from the full impact of undernutrition during this time in development.

Are substance P neurons of the paraventricular nucleus related to the osmotic regulation in the Mongolian gerbil?

In recent years, the gerbil has been used as an experimental animal for study osmotic regulation, because of its inherent high degree of water re-uptake in kidney. Many evidences to explain this characteristic accumulated on the kidney level, it do not, however, manifest what concerns on hypothalmo-hypophyseal level. In this study, we have focused on the difference between the colchicine treated gerbil and rat in distributions of substance P (SP), which is known to have antidiuretic property. Unlike rat, in which a few SP+ neuron is present, SP+ neurons were abundantly observed in the paraventricular nucleus (PVN) of the gerbil. Furthermore SP+ cells in PVN were manifested in dehydrated gerbils, in spite of non-colchicine treatment. Therefore, we suggest that the abundant SP+ neurons in PVN may be a clue to address the neuroendocrinal mechanism concerning the high degree of osmotic regulation in this animal.

Conjugation of drug to poly(D,L-lactic-co-glycolic acid) for controlled release from biodegradable microspheres

Poly(d,l-lactic-co-glycolic acid) (PLGA) was chemically conjugated to a model drug, N-(9-fluorenylmethoxycarbonyl-N-tert-butoxycarbonyl-l-tryptophan (Fmoc-Trp(Boc)) via an ester linkage. Various coupling reaction conditions were tested to optimize the conjugation process between a hydroxyl terminal group of PLGA and a carboxylic acid group of Fmoc-Trp(Boc). Two different lactic/glycolic acid compositions of PLGA (50/50 and 75/25) were used for the conjugation. The Fmoc-Trp(Boc)-PLGA conjugates were formulated into microspheres by a solvent evaporation technique for controlled release of Fmoc-Trp(Boc) over an one month period. A linear constant release of Fmoc-Trp(Boc) and its water-soluble PLGA oligomer conjugates was observed over an extended period without any initial burst effect, while unconjugated Fmoc-Trp(Boc) encapsulated within microspheres exhibited a rapid release profile. In addition, Fmoc-Trp(Boc) release rate solely depended on the PLGA composition that affected polymer degradation rate. The release rate of Fmoc-Trp(Boc) conjugated with fast degrading 50/50 PLGA was more rapid than that conjugated with relatively slow degrading 75/25 PLGA. This study demonstrates that PLGA-drug conjugation approach is a new and novel strategy to control the drug release rate from PLGA microspheres by utilizing the chemical degradation rate of PLGA backbone.

Rat osteopontin antibody is cross-reactive to a novel myelin-associated protein in chick

Osteopontin (OPN) was initially identified as glycosylated phosphoprotein in bones of vertebrates. Recently, OPN is reported to express in the primitive neuroepithelia of early chick embryonic hindbrain. We have demonstrated that rat OPN is immunohistochemically localized in the white matter of chick CNS. We have further confirmed the specificity of OPN cross-immunoreaction in myelin using demyelinated optic nerve induced by lysophosphatidylcholine (LPC), where the intensity of immunoreaction was closely related to the degree of demyelination. Immunoblot analyses showed that rat OPN antibody recognized a protein with molecular weights of approximately 47 kDa from chick CNS. Our data suggest that the antigen recognized by rat OPN is a previously undescribed myelin-associated protein in the chick CNS.

Lectins isolated from Korean mistletoe (Viscum album coloratum) induce apoptosis in tumor cells

Cytotoxic lectins (KML-C) were isolated from an extract of Korean mistletoe [Viscum album C. (coloratum)] by affinity chromatography on a hydrolysed Sepharose 4B column, and the chemical and biological properties of KML-C were examined, partly by comparing them with a lectin (EML-1) from European mistletoe[Viscum album L. (loranthaceae)]. The hemagglutinating activity of KML-C was inhibited by N-acetyl-D-galactosamine and D-galactose at the minimum concentrations of 6.3 and 12.5 microM/ml, respectively. Further biochemical analyses indicated that KML-C consists of four chains (Mr = 27.5, 30, 31 and 32.5 kDa) which, in some of the molecules, are disulfide-linked, and that the chains of KML-C are distributed over a broad range of isoelectric points (pI), 8.0 to 9.0, whereas the range for EML-1 is 6.6-7.0. A difference was also observed between the N-terminal sequences of KML-C and EML-1. The isolated lectins showed strong cytotoxicity against various human and murine tumor cells, and the cytotoxic activity of KML-C was higher than that of EML-1. Tumor cells treated with KML-C exhibited typical patterns of apoptotic cell death, such as apparent morphological changes and DNA fragmentation, and its apoptosis-inducing activity was blocked by addition of Zn2+, an inhibitor of Ca2+/Mg2+ -dependent endonucleases, in a dose-dependent manner. These results suggest that KML-C is a novel lectin related to the cytotoxicity of Korean mistletoe, and that its cytotoxic activity against tumor cells is due to apoptosis mediated by Ca2+/Mg2+ -dependent endonucleases.