Application of capillary nongel sieving electrophoresis for gene analysis

Capillary electrophoresis (CE) has proved to be a strong tool for DNA analysis and has found abundant applications in the fields of restriction fragment sizing, mutation screening, polymerase chain reaction (PCR) product characterizing and forensic identifying. CE may be the main alternative to slab gel electrophoresis. Capillary nongel electrophoresis is the most favorable mode when aiming for this purpose because of its advantages of long lifetime, easy operation, good reproducibility, and low expense. In this paper, a new kind of sieving matrix, with mannitol as the additive for capillary electrophoresis, as well as related methods and their application for gene analysis were reported. Nine DNA fragments amplified by multiplex PCR from a normal dystrophin gene were well separated by this system. Three different deletions were found in Duchenne muscular dystrophy (DMD) patients. Three to four copies of the sex-determination region of the Y chromosome (SRY) gene, as well as the phenylalanine hydroxylase (PAH) gene, could be detected in mixed samples. The frequencies of short tandem repeats (STR) in PAH genes was analyzed in 61 normal Chinese individuals and 6 phenylketonuria families. One case of prenatal gene diagnosis was performed. By using this matrix, CE coupled with reverse transcription PCR (RT-PCR), the analysis of the alternative splicing expression pattern of the fragile X mental retardation 1 (FMR1) gene in adult lung tissue was achieved.

Study of interaction between drug enantiomers and serum albumin by capillary electrophoresis

The interaction between drugs and human serum albumin (HSA) was investigated by capillary electrophoresis (CE). It involves stereoselectivity, drug displacement and synergism effects. Under protein-drug binding equilibrium, the unbound concentrations of drug enantiomers were measured by frontal analysis (FA). The stereoselectivity of verapamil (VER) binding to HSA was proved by the different free fractions of two enantiomers. In physiological pH (7.4, ionic strength 0.17 phosphate buffer) when 300 microM (+/-) VER were equilibrated with 500 microM HSA, the concentration of unbound S-VER was about 1.7 times its antipode. The binding constants of two enantiomers, K(R-VER) and K(S-VER), were 2670 and 850 M(-1), respectively. However, no obvious stereoselective binding of propranolol (PRO) to HSA was observed. Trimethyl-beta-cyclodextrin (45 mM) was used as a chiral selector in pH 2.5 phosphate buffer. Several drug systems were studied by the method. When ibuprofen (IBU) was added into VER-HSA solution. R-VER was partially displaced while S-VER was not displaced at all. A binding synergism effect between bupivacaine (BUP) and verapamil was observed and further study suggested that verapamil and bupivacaine occupy different binding site of HSA (site II and site III, respectively).

Study of enantioselective interactions between chiral drugs and serum albumin by capillary electrophoresis

The separation of the enantiomers of three basic drugs, i.e., ofloxacin, propranolol and verapamil, was achieved by affinity capillary electrophoresis (ACE), with human serum albumin (HSA) and bovine serum albumin (BSA) as chiral selectors in phosphate buffer at pH 7.4. Ofloxacin was only separated in the presence of BSA, and verapamil only with HSA, while propranolol was separated with either HSA or BSA. The effects of protein concentration and column wall adsorption on the degree of separation were investigated. Two displacers, ketoprofen and warfarin, respectively, when added to the protein containing buffer, both showed significant effects on the separation behavior. From these data it was argued that verapamil may bind to HSA at both locations known, the warfarin binding site (I) and the ketoprofen binding site (II). While with BSA, binding of ofloxacin may also occur at site I, the preferential binding site for propanolol remains controversial. A drug-drug interaction between propranolol and ketoprofen due to opposite charges was concluded from the increase in migration time in BSA solution. The unbound concentration of verapamil enantiomers in solution in the presence of HSA, as estimated from CD-modified capillary zone electrophoresis, was triggered not only by the HSA concentration but also by the coadditive concentration.

Separation of drugs by capillary electrophoresis, Part 10. Permethyl-alpha-cyclodextrin as chiral solvating agent

Following the German-Chinese Drug Screening Program, 86 racemic drugs were investigated in capillary zone electrophoresis in the presence of the chiral solvating agent (CSA) hexakis-(2,3,6-tri-O-methyl)-alpha-cyclodextrin (TM-alpha-CD). Of the 86 drugs, 23 were separated into enantiomeric pairs. A comparison of the migration separation factors (alpha(m)) and the migration retardation factors (Rm) with previously published data for native alpha-CD revealed that the 'upper-rim' hydroxyl groups do not necessarily facilitate the recognition of the drug enantiomers by the chiral host. In contrast, an overall increase in affinity for the permethylated host led to a higher rate of successful enantiomer separations. A key substructure (4H) was identified in the analyte structure domain, with a crucial influence on the behavior of a particular drug.

Mutational analyses of the putative calcium binding site and hinge of the turnip crinkle virus coat protein

The turnip crinkle carmovirus (TCV) coat protein (CP) is folded into R (RNA-binding), S (shell), and P (protruding) domains. The S domain is an eight-stranded beta barrel common to the coat protein subunits of most RNA viruses. A five-amino-acid hinge connects the S and P domains. In assembled particles, each pair of CP subunits is thought to bind a single calcium ion through interactions with three residues of one subunit and two residues of a neighboring subunit. These five residues comprise the putative calcium-binding site (CBS). The putative CBS and hinge are adjacent to one another. Mutations were introduced into the putative CBS or hinge in an effort to further determine the biological functions of TCV CP. One putative CBS mutant, TCV-M32, exhibited wild-type cell-to-cell movement but failed to move systemically in Nicotiana benthamiana, and particles were not detected. Another putative CBS mutant, TCV-M23, exhibited deficient cell-to-cell movement but particles accumulated in isolated protoplasts. Two other putative CBS mutants, TCV-M22 and -M33, showed wild-type cell-to-cell and systemic movement but elicited mild systemic symptoms that were somewhat delayed. All of the hinge mutants exhibited wild-type movement but some elicited non-wild-type symptoms. Point mutations in the putative CBS or hinge appear to alter virus-ion interactions, secondary structure, or particle conformation, thereby affecting interactions between the CP and plant hosts.

Bilirubin-human serum albumin interaction monitored by capillary zone electrophoresis

Capillary zone electrophoresis was used to monitor the interaction between bilirubin and human serum albumin. Cord blood serum samples were injected directly into an uncoated fused-silica capillary (30 cm x 50 microns i.d.) and separation was accomplished within 4 min without extensive sample pretreatment. The most suitable running buffer to separate free bilirubin from albumin bound bilirubin was found to contain 1.0 mmol/L EDTA, 5% acetonitrile and 15 mmol/L phosphate with pH adjusted to 8.4. Approximately two bilirubin dianions could be bound per human serum albumin molecule in the cord blood serum. The binding constant was estimated to be 1.1 x 10(5) (L/mol) at 25 degrees C and pH 8.4. The peak area ratio of free bilirubin to total bilirubin can be used to determine the bilirubin binding capacity of cord blood serum for the concentration range of total bilirubin from 204 to 340 mumol/L using 1:5 diluted cord blood seras.

NF-kappaB functions as both a proapoptotic and antiapoptotic regulatory factor within a single cell type

Recently NF-kappaB has been shown to have both proapoptotic and antiapoptotic functions. In T cell hybridomas, both T cell activators and glucocorticoids induce apoptosis. Here we show that blockade of NF-kappaB activity, using a dominant negative IkappaBalpha, has opposite effects on these two apoptotic signals. Treatment with PMA plus ionomycin (P/I) results in the upregulation of Fas Ligand (FasL) and induction of apoptosis. Inhibition of NF-kappaB activity inhibits the P/I mediated induction of FasL mRNA and decreases the level of apoptosis in these cultures, thus establishing NF-kappaB as a proapoptotic factor in this context. Conversely, inhibition of NF-kappaB confers a tenfold increase in glucocorticoid mediated apoptosis, establishing that NF-kappaB also functions as an antiapoptotic factor. We conclude that NF-kappaB is a context-dependent apoptosis regulator. Our data suggests that NF-kappaB may function as an antiapoptotic factor in thymocytes while functioning as a proapoptotic factor in mature peripheral T cells.

Geometrical and wave optics of paraxial beams

Most calculational techniques used to evaluate beam propagation are geared towards either fully coherent or fully incoherent beams. The intermediate partial-coherence regime, while in principle known for a long time, has received comparably little attention so far. The resulting shortage of adequate calculational techniques is currently being felt in the realm of x-ray optics where, with the advent of third generation synchrotron light sources, partially coherent beams become increasingly common. The purpose of this paper is to present a calculational approach which, utilizing a "variance matrix" representation of paraxial beams, allows for a straightforward evaluation of wave propagation through an optical system. Being capable of dealing with an arbitrary degree of coherence, this approach covers the whole range from wave to ray optics, in a seamless fashion.

Transmembrane topology of human glucose 6-phosphate transporter

Glycogen storage disease type 1b is caused by a deficiency in a glucose 6-phosphate transporter (G6PT) that translocates glucose 6-phosphate from the cytoplasm to the endoplasmic reticulum lumen where the active site of glucose 6-phosphatase is situated. Using amino- and carboxyl-terminal tagged G6PT, we demonstrate that proteolytic digestion of intact microsomes resulted in the cleavage of both tags, indicating that both termini of G6PT face the cytoplasm. This is consistent with ten and twelve transmembrane domain models for G6PT predicted by hydropathy analyses. A region of G6PT corresponding to amino acid residues 50-71, which constitute a transmembrane segment in the twelve-domain model, are situated in a 51-residue luminal loop in the ten-domain model. To determine which of these two models is correct, we generated two G6PT mutants, T53N and S55N, that created a potential Asn-linked glycosylation site at residues 53-55 (N53SS) or 55-57 (N55QS), respectively. N53SS or N55QS would be glycosylated only if it is situated in a luminal loop larger than 33 residues as predicted by the ten-domain model. Whereas wild-type G6PT is not a glycoprotein, both T53N and S55N mutants are glycosylated, strongly supporting the ten-helical model for G6PT.

Protein extravasation and cellular uptake after high-dose human-albumin treatment of transient focal cerebral ischemia in rats

Treatment with human albumin administered intravenously in the immediate post-ischemic period following a 2-h period of transient focal cerebral ischemia leads to a reduction of cortical infarction in rat. Immunohistochemistry with antibodies to rat immunoglobulins (IgG), rat albumin and (exogenous) human albumin was used to study blood-brain barrier changes. The degree of IgG extravasation was not changed by human-albumin treatment. Diffuse signals and uptake into necrotic neurons was seen in cortex of saline animals. In animals treated with human albumin, cortical neurons with preserved structural features had taken up human albumin. Treatment with human albumin may provide direct neuronal protection.

Accumulation of glycolipids in mutant Chinese hamster ovary cells (Z65) with defective peroxisomal assembly and comparison of the metabolic rate of glycosphingolipids between Z65 cells and wild-type CHO-K1 cells

The influence of peroxisomal dysfunction on glycosphingolipid metabolism was investigated using mutant Chinese hamster ovary (CHO) cells (Z65) with defective assembly of the peroxisomal membranes. In accordance with previous observations, the concentration of very long chain fatty acid (C24:0) was shown to be higher in Z65 cells than in control cells. We then compared the composition of glycolipids in Z65 cells with that in CHO-K1 cells, which are wild-type Chinese hamster ovary cells with intact peroxisomes, and found significantly increased concentrations of ceramide monohexoside (CMH) and ganglioside GM3 in Z65 cells. However, there were no differences in the concentrations of glycerophospholipids, triglycerides, free fatty acids and cholesterol between Z65 and CHO-K1 cells. Further, to investigate the metabolic rate of the major lipids, Z65 and CHO-K1 cells were pulse-labeled with [3-14C]serine. [3-14C]Serine was incorporated into phosphatidylserine, phosphatidylethanolamine and sphingomyelin more quickly in CHO-K1 than in Z65 cells. However, after 48 h, the radioactivity incorporated into those lipids, including CMH, was greater in Z65 cells than in CHO-K1 cells. Thus, the altered metabolism of glycosphingolipids, probably due to peroxisomal dysfunction, was thought to be responsible for the change in glycosphingolipid composition in Z65 cells.

Pteridine analysis in urine by capillary electrophoresis using laser-induced fluorescence detection

Pteridines are a class of compounds excreted in urine, the levels of which are found to elevate significantly in tumor-related diseases. For the first time, we have developed a method, based on high-performance capillary electrophoresis (HPCE) and laser-induced fluorescence (LIF) detection, to monitor the pteridine levels in urine. HPCE provides better separation than high-performance liquid chromatography and the LIF detector enables us to detect minute amounts of pteridines in body fluid. Eight different pteridine derivatives were well separated in 0.1 M Tris-0.1 M borate-2 mM EDTA buffer (pH 8.75) using a 60-cm fused-silica capillary (50-micron i.d., 35-cm effective length), six of which were detected and characterized in urine samples from normal persons and different cancer patients. The detection limits of these pteridines are under 1 x 10(-10) M. The levels of neopterin, pterine, xanthopterin, and pterin-6-carboxylic acid were found to be significantly elevated in urine excreted by cancer patents, while the level of isoxanthopterin dropped in these patients. No significant change of biopterin level was found between healthy individuals and cancer patients. This method can be used in clinical laboratories either for cancer monitoring or for precancer screening.

Progressive parenchymal deposition of beta-amyloid precursor protein in rat brain following global cerebral ischemia

In addition to producing acute neuronal necrosis within selectively vulnerable brain regions, our recent studies have shown that global cerebral ischemia may also be followed by protracted degenerative changes occurring over the course of 10 weeks. Chronic brain pathology may be associated with the abnormal deposition of beta-amyloid precursor protein (betaAPP). In the present study, we used a monoclonal antibody to the N-terminal portion of betaAPP to characterize the brains of rats surviving 1-10 weeks following 10 min of global brain ischemia produced by bilateral carotid artery occlusions plus systemic hypotension. After ischemia, increased betaAPP immunolabeling emerged in several brain regions. In the hippocampus, granular deposits appeared in the damaged CA1 area by 2 weeks, and by 4-10 weeks the remnants of necrotic CA1 neurons were also immunolabeled. In striatum and thalamus, regions with necrotic cell death also revealed granular betaAPP deposits. The neocortex was devoid of overt ischemic neuronal damage but revealed prominent betaAPP immunoreactivity. Large ovoid deposits of low-density betaAPP immunostaining occurred in cortical neurons at 1-2 weeks. At 4-10 weeks, large round or oval deposits immunoreactive for betaAPP appeared in several cortical regions. The highest density of deposits was seen in the temporal and piriform cortices. Our results indicate that abnormal betaAPP deposition may result from ischemic as well as chronic neurodegenerative processes.

[Chiral resolution by capillary electrophoresis]

The application and development in the field of chiral resolution by capillary electrophoresis are reviewed according to recent references, including different operating models and different chiral selectors. The study on mechanism of chiral resolution is summarized as well. It appears that capillary electrophoresis is one of the most effective, fast and simple methods in chiral resolution.

[Intersection point rule for the retention value with mobile phase composition and boiling point of the homologues and chlorobenzenes in soil leaching column chromatography]

Based on the linear retention equation of the logarithm of the capacity factor (logk') vs. the methanol volume fraction (psi) of aqueous binary mobile phase in soil leaching column chromatography, the intersection point rule for the logk' of homologues and weak polar chlorobenzenes, with psi, as well as with boiling point, has been derived due to existence of the similar interactions among solutes of the same series, stationary phase (soil) and eluent (methanol-water). These rules were testified by experimental data of homologues (n-alkylbenzenes, methylbenzenes) and weak polar chlorobenzenes.

[Albumin-drug binding study by capillary electrophoresis. I. Quantitative applicability examination of liquid pre-column]

To measure the free concentration of verapamil (a basic drug) enantiomers in the binding system of human serum albumin(HSA), a capillary electrophoretic method, liquid precolumn(LCP), was established, and the method was examined systematically. In physiological pH condition (pH 7.4, ionic strength 0.17), HSA migrates in the opposite direction of verapamil. This electrophoretic property basically supposed the probability of preventing HSA from entering the capillary whereas a positive electric field was used. Finally, the drug enantiomers were separated by the chiral selector (45 mmol/L trimethyl-beta-cyclodextrin, pH 2.5 phosphate buffer) and the free concentration of each optical isomer in the binding system was measured. Seven samples were examined and their relative standard deviations(RSD) and the relative errors (RE) of unbound drug were 2.1%-5.02% and 1.4%-5.8%, respectively.

[Albumin-drug binding study by capillary electrophoresis. II. Determination of drug enantiomeric binding constants]

A capillary electrophoresis (CE) method was applied to determine the binding constants of the basic racemic drug, verapamil (VER) to human serum albumin (HSA) under drug-HSA binding equilibrium (in phosphae buffer pH 7.4, ionic strength = 0.17). In coated capillary, the unbound basic drug eluted as two zonal plateau peaks due to enantiomers separated by chiral selector (45 mmol/L trimethyl-beta-cyclodextrin dissolved in pH 2.5 phosphate buffer) at 15 kV, and their concentrations can be determined from the peak heights. To avoid disturbing the VER-HSA equilibrium, the pH 7.4 solution was used as the inlet vial buffer, and a plug(about 3 cm long) of this buffer was introduced to the capillary before injection of analyte. The binding constants were obtained from linear regression plots. The unbound concentration of S-VER was 1.67 times higher than that of the antipode for the solution 300 mumol/L (+/-) VER-500 mumol/L HSA, while 1.13 for 100 mumol/L (+/-) VER-100 mumol/L HSA. The study confidently provides the binding constants of VER enantiomers to HSA, which are KR = 2.7 x 10(3) (+/- 4.4 x 10(2)) and Ks = 8.5 x 10(3) (+/- 1.0 x 10(2)).

Inactivation of the glucose 6-phosphate transporter causes glycogen storage disease type 1b

Glycogen storage disease type 1b (GSD-1b) is proposed to be caused by a deficiency in microsomal glucose 6-phosphate (G6P) transport, causing a loss of glucose-6-phosphatase activity and glucose homeostasis. However, for decades, this disorder has defied molecular characterization. In this study, we characterize the structural organization of the G6P transporter gene and identify mutations in the gene that segregate with the GSD-1b disorder. We report the functional characterization of the recombinant G6P transporter and demonstrate that mutations uncovered in GSD-1b patients disrupt G6P transport. Our results, for the first time, define a molecular basis for functional deficiency in GSD-1b and raise the possibility that the defective G6P transporter contributes to neutropenia and neutrophil/monocyte dysfunctions characteristic of GSD-1b patients.

[Temperature effect and temperature gradient technology in capillary electrophoresis]

A review is given here to describe the temperature effect and temperature gradient technology in capillary electrophoresis (CE). The temperature effects on the analysis of DNA, protein peptides and amino acids, enantiomers, carbohydrates and other substances are discussed respectively. The theory of temperature effect is also mentioned. The importance of the temperature gradient in CE, the classifications of gradient technology in CE, the potential applications and different method development of the temperature gradient are described. Fifty-one references are cited.

[Investigation of association parameters of basic drugs to human serum albumin by capillary zone electrophoresis/frontal analysis]

A CZE/FA method was applied to the study of association parameters of basic drugs, verapamil (VER) and propranolol (PRO), to human serum albumin (HSA) under drug-HSA association equilibria. After the direct hydrodynamic injection of a drug-HSA mixed solution into a coated capillary (effective length, 32 cm; 50 microns i.d.), the basic drug is eluted as a zonal peak with a plateau region under condition of phosphate buffer (pH 7.4, ionic strength = 0.17) at 10 kV running voltage. The unbound concentration of drug can be determined from the plateau peak height with good linear response, r = 0.999 for both VER(n = 6) and PRO(n = 8), respectively. Six VER-HSA solutions (containing 50-175 mumol/L of VER and 450-325 mumol/L of HSA) and eight PRO-HSA solutions (containing 50-400 mumol/L of VER and 450-100 mumol/L of HSA) were investigated. Three analytical methods were used for the present CZE/FA system including Scatchard, Klotz and non-linear regression analyses. The estimated association parameters were as follows: the numbers of HSA binding site n for VER were over 1.21(0.04)-1.30(0.09), binding constant, K, was between 1,690(130) and 1,790(70). Whereas for PRO, n = 0.54(0.04)-0.62(0.03), and K = 1,390(70)-1,690(180). The data deduced from these three analyses agreed well with each other.

[Application of capillary non-gel sieving electrophoresis to the analysis of short tandem repeat in phenylalanine hydroxylase gene and gene diagnosis of phenylketonuria]

OBJECTIVE

To establish a sensitive, accurate and reliable method for analysis of short tandem repeat (STR) markers for gene diagnosis, capillary electrophoresis (CE) was used for analysis of a polymorphic tetranucleotide (TCTA)n in intron 3 of the phenylalanine hydroxylase (PAH) gene.

METHODS

Capillary non-gel sieving electrophoresis (CNGSE) system was used to analyze PCR products of PAH STR among 61 normal Chinese individuals and 6 phenylketonuria (PKU) families.

RESULTS

The PCR fragments that differ 4 bp from each other were well separated by CNGSE. Ten alleles were identified, with a continuous distribution from 224 bp to 260 bp. The largest allele (260 bp) was first detected in Chinese population. The alleles frequencies were calculated and PIC is 0.738. The genotypes of PAH STR of total 80 Chinese people were also analyzed and the heterozygosity is 75%. We used this procedure to PAH gene linkage analysis in 6 PKU families, in which pathogenic gene could be affirmed in 3 families, including one case of prenatal diagnosis.

CONCLUSIONS

In comparison with denaturing polyacrylamide gel electrophoresis, CE is an accurate, rapid, automatic and with high resolution analytical tool. CE in combination with PCR is a hopeful technique and might be widely used for gene diagnosis of genetic diseases in the future.

Diffusion-weighted magnetic resonance imaging confirms marked neuroprotective efficacy of albumin therapy in focal cerebral ischemia

BACKGROUND AND PURPOSE

We have recently shown high-dose human serum albumin therapy to confer marked histological protection in experimental middle cerebral artery occlusion (MCAo). We have now used diffusion-weighted magnetic resonance imaging (DWI) in conjunction with morphological methods to expand our understanding of this therapeutic approach.

METHODS

Physiologically controlled Sprague-Dawley rats received 2-hour MCAo by the modified intraluminal suture method. Treated rats received 25% human serum albumin solution (1% by body weight) immediately after the MCA was reopened. Vehicle-treated rats received saline. Computer-based image averaging was used to analyze DWI data obtained 24 hours after MCAo and light-microscopic histopathology obtained at 3 days. In a matched series, plasma osmolality and colloid oncotic pressure, as well as brain water content, were determined.

RESULTS

Albumin therapy, which lowered the hematocrit on average by 37% and raised plasma colloid oncotic pressure by 56%, improved the neurological score throughout the 3-day survival period. Within the ischemic focus, the apparent diffusion coefficient (ADC) computed from DWI data declined by 40% in vehicle-treated rats but was preserved at near-normal levels (8% decline) in albumin-treated rats (P<0.001). Albumin also led to higher ADC values within unlesioned brain regions. Histology revealed large consistent cortical and subcortical infarcts in vehicle-treated rats, while albumin therapy reduced infarct volume at these sites, on average, by 84% and 33%, respectively. Total infarct volume was reduced by 66% and brain swelling was virtually eliminated by albumin treatment. Microscopically, while infarcted regions of vehicle-treated rats had the typical changes of pannecrosis, infarcted zones of albumin-treated brains showed persistence of vascular endothelium and prominent microglial activation, suggesting that albumin therapy may help to preserve the neuropil within zones of residual infarction.

CONCLUSIONS

These findings confirm the striking neuroprotective efficacy of albumin therapy in focal cerebral ischemia and reveal that this effect is associated with DWI normalization and a mitigation of pannecrotic changes within zones of residual injury.

Hyperglycemic exacerbation of neuronal damage following forebrain ischemia: microglial, astrocytic and endothelial alterations

We undertook a detailed characterization of the cellular responses to acute global cerebral ischemia complicated by hyperglycemia. Anesthetized, physiologically monitored male Wistar rats received 12.5 min of global forebrain ischemia by bilateral common carotid artery occlusions plus hemorrhagic hypotension to 45 mmHg. Cranial temperature was maintained at normothermic levels. Hyperglycemic animals received dextrose (2.5 ml of a 25% solution, intraperitoneally) prior to ischemia; this doubled the mean plasma glucose concentration to 296 mg/100 ml. At 3 days (n = 10) or 24 h (n = 4) after ischemia, brains were perfusion-fixed and paraffin-embedded for light microscopic histopathology and for the histochemical visualization of activated microglia and the immunocytochemical visualization of glial fibrillary acid protein. Normal-neuron counts in the vulnerable hippocampal CA1 sector of hyperglycemic-ischemic (HI) rats were reduced to one-third the number observed in normoglycemic-ischemic (NI) animals. Ischemic cell counts in the striatum were increased fivefold or more in HI compared to NI rats, and normal small-neuron counts were reduced by two-thirds. The neocortex and striatum of NI rats showed only mild damage, while the majority of HI rats had extensive lesions, and several showed large cortical, striatal or thalamic infarcts. In addition, widespread cortical ischemic neuronal changes were evident in HI animals. No endothelial alterations were present in NI rats. By contrast, HI rats showed prominent peri- and intravascular polymorphonuclear and monocytic accumulation evident at 24 h; frequent white cell thrombi in pial arterioles on day 3; and thickening of vascular endothelium, with foci of parenchymal rarefaction or microinfarction adjacent to occluded vessels. Prominent microglial activation, often along the course of penetrating blood vessels, was common in the striatum and neocortex of HI animals but was much less extensive in the NI group. Activated microglia in HI rats were typically hypertrophic and amoeboid. These results suggest that the detrimental influence of hyperglycemia in ischemia is initially mediated by an action on vascular endothelium, which in turn leads to widespread foci of infarction and neuronal loss.

Cloning and characterization of cDNAs encoding a candidate glycogen storage disease type 1b protein in rodents

Glycogen storage disease type 1 (GSD-1) is a group of genetic disorders caused by a deficiency in the activity of the enzyme glucose-6-phosphatase. (G6Pase). GSD-1a and GSD-1b, the two major subgroups, have been confirmed at the molecular genetic level. The gene responsible for GSD-1b maps to human chromosome 11q23 and a candidate human GSD-1b cDNA that encodes a microsomal transmembrane protein has been identified. In this study, we show that this cDNA maps to chromosome 11q23; thus it is a strong candidate for GSD-1b. Furthermore, we isolated and characterized candidate murine and rat GSD-1b cDNAs. Both encode transmembrane proteins sharing 93-95% sequence homology to the human GSD-1b protein. The expression profiles of murine GSD-1b and G6Pase differ both in the liver and in the kidney; the GSD-1b transcript appears before the G6Pase mRNA during development. In addition to G6Pase deficiency, GSD-1b patients suffer neutropenia, neutrophil dysfunction, and recurrent bacterial infections. Interestingly, although the G6Pase mRNA is expressed primarily in the liver, kidney, and intestine, the GSD-1b mRNA is expressed in numerous tissues, including human neutrophils/monocytes.

Hepatocyte nuclear factor 1alpha is an accessory factor required for activation of glucose-6-phosphatase gene transcription by glucocorticoids

Deficiency of glucose-6-phosphatase (G6Pase), a key enzyme in glucose homeostasis, causes glycogen storage disease type 1a (GSD-1a), also know as von Gierke disease. Expression of the G6Pase gene is regulated by multiple hormones, including glucocorticoids. The synthetic glucocorticoid dexamethasone increased G6Pase mRNA abundance and gene transcription in H4-IIE hepatoma cells. Transient transfection assays demonstrated that the G6Pase promoter was active in H4-IIE cells only in the presence of dexamethasone. The minimal G6Pase promoter was contained within nucleotides -234/+3, which has two putative glucocorticoid response elements (GREs) at nucleotides -178/-164 (site 1) and -154/-140 (site 2). Electromobility shift and transient transfection assays showed that only GRE site 1 was required for glucocorticoid-activated transcription from the G6Pase promoter. Deletion analysis demonstrated that the DNA elements absolutely essential for glucocorticoid-stimulated transcription from the G6Pase promoter were contained within nucleotides -234/-212, encompassing binding motifs for hepatocyte nuclear factors (HNFs) 1 (-226/-212) and 4 (-231/-220). Electromobility shift and cotransfection assays showed that HNF1alpha bound to its cognate site and mediated transcription activation of the G6Pase gene by glucocorticoids.

Growth restriction of dengue virus type 2 by site-specific mutagenesis of virus-encoded glycoproteins

The three flavivirus glycoproteins prM, E and NS1 are formed by post-translational cleavage and are glycosylated by the addition of N-linked glycans. NS1 may form homodimers, whereas E may form homodimers, homotrimers or heterodimers (prM-E). Modification of these processes by mutagenesis of the proteins has the potential to generate viruses that are restricted in growth and are possible vaccine candidates. Using an SV40-based expression system, we previously analysed dimerization and secretion of the NS1 protein of dengue virus type 2 (DEN-2) with mutations in the conserved Cys residues, or within hydrophilic or hydrophobic regions, or at glycosylation sites. In this study, mutations which reduce cleavage at the DEN-2 prM/E signalase cleavage site are described. On the basis of earlier and current results with transient expression, six mutations which reduced NS1 dimerization and two mutations which inhibited prM/E cleavage were analysed individually for their effects on virus growth using a genomic length cDNA clone. Two viruses were obtained that showed reduced growth in cell culture and attenuation of neurovirulence when inoculated into 3-day-old mice. One of these viruses encoded NS1 that lacked the second glycosylation site, the other encoded a Ser --> Ile change at the -3 position of the prM/E cleavage site. A third virus encoding a mutation in NS1 within a hydrophilic region grew as well as the parental virus. No virus was detected for the remaining five mutations.

Normal phosphorylation of duck hepatitis B virus L protein is dispensable for infectivity

A fraction of the large surface protein (L) of duck hepatitis B virus (DHBV) is phosphorylated at serine or threonine residues (E. Grgacic & D. Anderson, Journal of Virology 68, 7344-7350, 1994). We now report the identification of phosphorylation sites in DHBV L protein. Using site-directed mutagenesis, we have identified serine-118 (S118) as the major phosphorylation site, accepting approximately 64% of the total phosphate groups incorporated in L, and resulting in retarded migration of phosphorylated L in SDS-PAGE. Proline-119 is indispensable for S118 phosphorylation. Mutation of other serine/threonine residues which are followed by prolines (T79, T89, S117 and T155) together with S118 further reduced phosphorylation to around 19% of wild-type. Non-equilibrium pH gel electrophoresis (NEPHGE) and SDS-PAGE of 33P-labelled L protein revealed two phosphorylated L species, while protein with the S118 to alanine mutation was detected as only one labelled species, consistent with multiple phosphorylations in wild-type L. Together, these results demonstrate that serine 118 is the major phosphorylation site for a proline-directed kinase, and that a proportion of L molecules are additionally phosphorylated at one of a number of secondary sites. DHBV mutants encoding L proteins with minimal phosphorylation (alanine mutants) or mimicking constitutive phosphorylation (aspartic acid mutants) remained infectious both in cell culture and in ducks, demonstrating that L phosphorylation may play only a minor role in DHBV replication.

[Influence of mannitol additive on DNA separation by capillary non-gel sieving electrophoresis]

Polymer solutions with high concentration were employed as sieving buffer in order to obtain satisfactory separation of smaller DNA fragments with length of less than 1,000 base pairs. The concentrated polymer solution had very high viscosity, which was difficult to be pumped into or out of the capillary. Mannitol additive can enhance the sieving ability of hydroxy-propylmethylcellulose (HPMC) solution in a Tris-Borate-EDTA background electrolyte. With the existence of mannitol, good separation of PGEM-3Zf(+)/Hae III was able to be obtained in a less concentrated HPMC solution with relatively low viscosity. The optimum mass concentration of mannitol was investigated and it was found that 60 g/L mannitol could give the best results. Mannitol chain could be formed through hydrogen bond among mannitol, HPMC and borate. This kind of mannitol chain shaped the network and decreased the pore size, so the separation was greatly enhanced.

[Enantioseparation of chlorpheniramine and EMD-56431 by micellar electrokinetic capillary chromatography using deoxycholate salt and beta-cyclodextrin]

Two chiral drugs of EMD-56431 and chlorpheniramine are separated by cyclodextrin-modified micellar electrokinetic capillary chromatography using beta-cyclodextrin(beta-CD) and sodium deoxycholate(SDC) as selector in the paper. All the electrolytes in experiments contain 0.1 mol/L borate. The length of capillary is 45.0 cm as total and 30.0 cm as effective. The running and loading voltages are all 7.8 kV. The effects of pH and concentrations of SDC and beta-CD are studied, in which the best chiral separation conditions for EMD-56431 are pH 10.4, [beta-CD] = 50 mmol/L, [SDC] = 150 mmol/L, and those for chlorpheniramine are pH 9.0, [beta-CD] = 50 mmol/L, [SDC] = 100 mmol/L. The mechanism of chiral separation for the buffer system is initially believed as: the micellar monomer exists almost all as inclusion body with beta-CD, some CD-SDC inclusion complex may exist in micellar because the SDC micellar's gather number is only 4 and the SDC molecular is so big that it can only partly enter beta-CD. Then, the good separation ability of the system is supplied while the ratio of concentration between SDC and beta-CD is in 4:1-4:3; but there will be a optimized total concentration for SDC and beta-CD. The complex interaction among sample, SDC and beta-CD makes intricate change for migration along with the selector's concentration, and the same complex results are also made in pH experiments because of electroosmosis and the acidity of SDC and components. The phenomenon of increasing beta-CD solubility is showed. The beta-CD's solubility with 100 mmol/L SDC can be increased above 150 mmol/L.

Bidirectional regulation of uncoupling protein-3 and GLUT-4 mRNA in skeletal muscle by cold

To elucidate the possible role of the mitochondrial uncoupling protein (UCP)-3 in skeletal muscle as a regulator of adaptive thermogenesis and energy balance, we examined the modulation by cold exposure (5 degrees C) of UCP-3 and glucose transporter isoform GLUT-4 mRNAs in male Sprague-Dawley rats. In skeletal muscle, UCP-3 and GLUT-4 mRNAs increased two- to threefold between 6 and 24 h of cold exposure and then decreased to 50% of the control value after 6 days in the cold. In contrast, skeletal muscle UCP-2 mRNA showed a small increase on day 3 and returned to normal after 6 days. The bidirectional regulation of UCP-3 and GLUT-4 mRNAs in skeletal muscle by cold suggests that UCP-3 may be a major mediator of acute adaptive thermogenesis but then is downregulated, along with GLUT-4, in the chronic state to preserve energy. In contrast, cold exposure caused only transient changes of UCP-2 and GLUT-4 mRNA in heart. These data are consistent with the necessity of the heart to continuously expend energy to maintain blood circulation, regardless of environmental conditions.

Molecular determinants of AHPN (CD437)-induced growth arrest and apoptosis in human lung cancer cell lines

6-[3-(1-Adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (AHPN or CD437), originally identified as a retinoic acid receptor gamma-selective retinoid, was previously shown to induce growth inhibition and apoptosis in human breast cancer cells. In this study, we investigated the role of AHPN/CD437 and its mechanism of action in human lung cancer cell lines. Our results demonstrated that AHPN/CD437 effectively inhibited lung cancer cell growth by inducing G0/G1 arrest and apoptosis, a process that is accompanied by rapid induction of c-Jun, nur77, and p21(WAF1/CIP1). In addition, we found that expression of p53 and Bcl-2 was differentially regulated by AHPN/CD437 in different lung cancer cell lines and may play a role in regulating AHPN/CD437-induced apoptotic process. On constitutive expression of the c-JunAla(63,73) protein, a dominant-negative inhibitor of c-Jun, in A549 cells, nur77 expression and apoptosis induction by AHPN/CD437 were impaired, whereas p21(WAF1/CIP1) induction and G0/G1 arrest were not affected. Furthermore, overexpression of antisense nur77 RNA in A549 and H460 lung cancer cell lines largely inhibited AHPN/CD437-induced apoptosis. Thus, expression of c-Jun and nur77 plays a critical role in AHPN/CD437-induced apoptosis. Together, our results reveal a novel pathway for retinoid-induced apoptosis and suggest that AHPN/CD437 or analogs may have a better therapeutic efficacy against lung cancer.

Diffuse ocular metastases as an initial sign of metastatic lung cancer

A 68-year-old man with lung carcinoma and no systemic metastasis presented with a blind, painful right eye. Examination showed no perception of light in the affected eye, elevated intraocular pressure, marked epibulbar hyperemia, and a white placoid mass in the conjunctiva nasally. Although a cataract precluded a clear view of the fundus, ultrasonography disclosed a total retinal detachment and a diffuse thickening of the choroid. Metastatic carcinoma was suspected clinically and the eye was enucleated because of severe, intractable pain. Pathologic examination demonstrated extensively necrotic metastatic adenocarcinoma involving the conjunctiva, peripheral cornea, sclera, iris, ciliary body, choroid, optic nerve, subarachnoid space, and orbit. Metastatic disease usually affects a singular ocular tissue, and it is highly unusual for such widespread ocular involvement to be the first sign of systemic metastasis from a primary neoplasm.

Halide effects in the hydrolysis reactions of (+/-)-7beta, 8alpha-dihydroxy-9alpha,10alpha-epoxy-7,8,9,10-tetrahydrobenzo- [a]pyrene

Rates of reaction of (+/-)-7beta,8alpha-dihydroxy-9alpha, 10alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (DE-2) have been determined in 1:9 dioxane-water solutions containing 1.0 M KCl, 0.5 M KBr, and 0.1 M NaI over the pH range 4-13. These pH-rate profiles are more complicated than those for reaction of DE-2 in 0.2 M NaClO4 solutions and are interpreted in part by mechanisms in which halide ion attacks the diol epoxide as a nucleophile at intermediate pH, resulting in the formation of a trans-halohydrin. Reaction of DE-2 in these halide solutions at pH < ca. 5 occurs by rate-limiting carbocation formation, followed by capture of the intermediate carbocation by halide ion. The relative magnitudes of the rate constants for reaction of the intermediate carbocation with halide ions are estimated from product studies. The halohydrins are unstable intermediates and react quickly in subsequent reactions to yield tetrols in a ratio different than that formed from reaction of the carbocation with solvent. Nucleophilic attacks of 1.0 M Cl-, 0.5 M Br-, and 0.1 M I- on DE-2 are the principal reactions in the pH range ca. 6-9, leading to intermediate trans-halohydrins that hydrolyze to tetrols. At pH ca. 9-11, halohydrin formed from attack of halide ion on DE-2 reverts back to epoxide, leading to a negative break in the pH-rate profile. The main product-forming reaction of DE-2 at pH 11.3 is the spontaneous reaction. At pH > 12, the rate of reaction of DE-2 increases due to a second-order reaction of HO- with DE-2.

Sequential analysis of subacute and chronic neuronal, astrocytic and microglial alterations after transient global ischemia in rats

Recent experimental investigations have emphasized the importance of assessing both acute and chronic histopathological changes occurring after cerebral ischemia. The purpose of this study was to evaluate the temporal profile of neuronal, astrocytic and microglial alterations within vulnerable regions (striatum and CA1 sector of hippocampus) following transient global ischemia. Anesthetized Wistar rats underwent 10 min of normothermic (37 degrees C) ischemia induced by bilateral carotid ligations plus hypotension (45-50 mm Hg) and were allowed to survive for periods ranging from 1 to 10 weeks (n=4-6/group) prior to quantitative histopathological analysis. Adjacent sections were examined by hematoxylin-and-eosin histopathology, immunostaining for glial fibrillary acidic protein, and B4-isolectin immunochemistry for microglia. In the striatum, normal-neuron counts were first decreased significantly at 2 weeks after the ischemic insult. Neuronal loss was associated with the proliferation of reactive microglia, which peaked at 1 week. By contrast, reactive astrocytosis displayed a more protracted pattern, with peak activation at 2 weeks. In the CA1 hippocampus, a decreased number of normal neurons was seen at 1 week post ischemia, together with a significant increase in immunoreactive microglia at that time; the latter normalized after 2 weeks. Reactive astrocytes in the CA1 hippocampus were significantly increased at 1-2 weeks after ischemia. In a subgroup of severely injured animals, foci of frank striatal infarction were associated with early and severe microglial and astrocytic proliferation at week 4 or later. Finally, cerebrovascular changes included endothelial disruption within affected areas. These observations document a subacute and chronic sequence of cellular responses following brief periods of global ischemia, involving both neurons, glia and vascular endothelium.

[Application of capillary electrophoresis on environmental analysis]

A review of applications of capillary electrophoresis (CE) on environmental analysis is presented, based mainly on the worldwide published works in the latest years. The current achievements and application potential of CE in the field of environmental analysis are included with 58 references.

Pharmacokinetics and urinary excretion of DMXBA (GTS-21), a compound enhancing cognition

DMXBA (3-(2,4-dimethoxybenzylidene)-anabaseine, also known as GTS-21) is currently being tested as a possible pharmacological treatment of cognitive dysfunction in Alzheimer's disease. In this study, plasma and brain pharmacokinetics as well as urinary excretion of this compound have been evaluated in adult rats. DMXBA concentrations were determined by HPLC. Following a 5 mg kg-1 iv dose, DMXBA plasma concentration declined bi-exponentially with mean (+/- SE) absorption and elimination half-lives of 0.71 +/- 0.28 and 3.71 +/- 1.12 h, respectively. The apparent steady state volume of distribution was 2150 +/- 433 mL kg-1, total body clearance was 1480 +/- 273 mL h-1 kg-1, and AUC0-infinity was 3790 +/- 630 ng h mL-1. Orally administered DMXBA was rapidly absorbed. After oral administration of 10 mg kg-1, a peak plasma concentration of 1010 +/- 212 ng mL-1 was observed at 10 min after dosing. Elimination half-life was 1.740 +/- 0.34 h, and AUC0-infinity was 1440 +/- 358 ng h mL-1. DMXBA peak brain concentration after oral administration was 664 +/- 103 ng g-1 tissue, with an essentially constant brain-plasma concentration ratio of 2.61 +/- 0.34, which indicates that the drug readily passes across the blood-brain barrier. Serum protein binding was 80.3 +/- 1.1%. Apparent oral bioavailability was 19%. Renal clearance (21.8 mL h-1 kg-1) was less than 2% of the total clearance (1480 +/- 273 mL h-1 kg-1); urinary excretion of unchanged DMXBA over a 96 h period accounted for only 0.28 +/- 0.03% of the total orally administered dose. Our data indicates that DMXBA oral bioavailability is primarily limited by hepatic metabolism.

Intracellular retention of duck hepatitis B virus large surface protein is independent of preS topology

The mechanism of intracellular retention for the large surface protein (L) of duck hepatitis B virus (DHBV) was analyzed by examination of the transmembrane topologies and secretory properties of a collection of DHBV L mutants and compared with that of human hepatitis B virus (HBV) L. Our results demonstrate that, in contrast to its HBV counterpart, intracellular retention of DHBV L does not depend on the cytosolic disposition of its preS domain. L mutants with either cytosolic or lumenal preS were mostly retained in the absence of the small surface protein (S), whereas coexpression with S resulted in efficient secretion of both topological forms. Coexpression of the wild-type DHBV L with S resulted in efficient incorporation of L into secreted S + L particles, whereas HBV L was partially excluded from secreted particles under the same conditions. We propose that HBV provides L retention even in the presence of an excess of S, by exclusion of molecules with cytosolic preS domains from secreted particles at the stage of their assembly. DHBV lacks such a retention mechanism due to the absence of topological selection in particulate assembly.

Correlation of gallbladder ejection fraction with pathologic grade for chronic inflammation

BACKGROUND

The purpose of this study is to define the sensitivity and specificity of the gallbladder ejection fraction (GBEF) for identifying patients with various grades of histologically proven chronic cholecystitis.

METHODS

Of 693 consecutive patients who had a scintigraphic GBEF determination at Baptist Medical Center of Oklahoma, 161 subsequently had a cholecystectomy at the same institution. Pathologic material was reassessed by one outside blinded reviewer, who graded the intensity of the inflammation present on a 0 (absent) to 3 (most severe) scale.

RESULTS

The least square mean maximum GBEF was 23.7% for those with grade 0, 9.6% for those with grade 3, and 13.9% for those with cholesterolosis. If a normal value for GBEF is set at > 30%, the sensitivity for detecting grade 1, 2, or 3 disease was 84%, and the specificity was 26%. For grade 3 disease alone, the sensitivity was 100%, and the specificity was 26%.

CONCLUSIONS

The GBEF is sensitive but not specific for chronic inflammation of the gallbladder. The GBEF appears to be useful as a screening examination in the appropriate clinical setting.

Separation of enantiomers of drugs by capillary electrophoresis. V. Hydroxypropyl-alpha-cyclodextrin as chiral solvating agent

In an extended chiral drug screening program, enantioseparation of 86 racemic drugs was tested with hydroxypropyl-alpha-cyclodextrin as chiral solvating agent (CSA). A total of 34 drugs out of 86 could be resolved in this straightforward approach. The number of experiments performed under identical conditions allows a correlation of the separation factors alpha(m) with the interaction strengths Rm. As shown for a subset of 23 drugs, the concentration of the CSA is a crucial parameter for further optimization.

Alteration of acidic lipids in human sera during the course of pregnancy: characteristic increase in the concentration of cholesterol sulfate

In this study, we determined the concentrations of acidic lipids, including cholesterol sulfate (CS), sulfatide and GM3 ganglioside, in human sera of non-pregnant state and during the course of pregnancy. In human sera of non-pregnant women, GM3 was present at a concentration of 8 nmol/ml and the concentrations of CS and sulfatides were less than 20% of that of GM3. The concentration of sulfatides in sera at the second trimester of gestation was decreased, but CS gradually increased from the first to the third trimester of gestation with a correlation coefficient of 0.66, and a correlation between the concentration of CS and weeks of gestation (p<0.01). CS was also contained in the placental villi, and its concentration increased from the first to the third trimester of gestation, suggesting that placental CS is one of the source of CS in the blood by shedding.

The role of HNF1alpha, HNF3gamma, and cyclic AMP in glucose-6-phosphatase gene activation

The gene for glucose-6-phosphatase (G6Pase), the key enzyme in glucose homeostasis, is expressed in a tissue-specific manner in the liver and kidney. To understand the molecular mechanisms regulating liver-specific expression of the G6Pase gene, we characterized G6Pase promoter activity by transient expression assays. The G6Pase promoter is active in HepG2 hepatoma cells, but inactive in JEG3 choriocarcinoma or 3T3 cells. DNA elements essential for optimal and liver-specific expression of the G6Pase gene were contained within nucleotides -234 to +3. Deletion analysis revealed that the G6Pase promoter contained three activation elements (AEs) at nucleotides -234 to -212 (AE-I), -146 to -125 (AE-II), and -124 to -71 (AE-III). AE-I contains binding sites for hepatocyte nuclear factors (HNF) 1 and 4. Electromobility shift and cotransfection assays demonstrated that HNF1alpha, but not HNF4, bound to its cognate site and transactivated G6Pase gene expression. The G6Pase promoter contained five HNF3 motifs, 1 (-180/-174), 2 (-139/-133), 3 (-91/-85), 4 (-81/-75), and 5 (-72/-66), and all five sites bound HNF3gamma with high affinity. Transient expression and cotransfection assays showed that HNF3 site 1 is not required for basal promoter activity, but is essential for HNF3gamma-activated transcription from the G6Pase promoter. We further showed that HNF3 sites 3, 4, and 5 were essential for basal G6Pase promoter activity and transactivation by HNF3gamma. AE-II contains, in addition to a HNF3 motif, a cAMP-response element (CRE) and a C/EBP half-site. The G6Pase(-146/-116) DNA containing AE-II formed multiple protein-DNA complexes with HepG2 nuclear extracts, including HNF3gamma, CRE-binding protein (CREB), C/EBPalpha, and C/EBPbeta. We showed that AE-II mediated transcription activation of the G6Pase gene by cAMP.

[Somatostatin in NRM plays roles in inducing analgesia and enhancing electroacupuncture analgesia]

The effects of microinjection of somatostatin (SS), somatostatin depletor cysteamine (CS) and anti-somatostatin serum (ASSS) on the pain threshold (PT) and electroacupuncture (EA) analgesia were investigated in the rat. The potassium iontophoresis induced tail-flick was used to measure the pain threshold. The "Zusanli" were stimulated with EA. The results indicated that microinjection of SS into necleus raphe magnus (NRM), could elevate PT and enhance EA analgesia. PT and EA analgesia were decreased when SS in NRM was depleted by CS or neutralized by ASSS. These data revealed that SS in NRM plays important roles in inducing analgesia and enhancing electroacupuncture analgesia.

Inhibition of trans-retinoic acid-resistant human breast cancer cell growth by retinoid X receptor-selective retinoids

All-trans-retinoic acid (trans-RA) and other retinoids exert anticancer effects through two types of retinoid receptors, the RA receptors (RARs) and retinoid X receptors (RXRs). Previous studies demonstrated that the growth-inhibitory effects of trans-RA and related retinoids are impaired in certain estrogen-independent breast cancer cell lines due to their lower levels of RAR alpha and RARbeta. In this study, we evaluated several synthetic retinoids for their ability to induce growth inhibition and apoptosis in both trans-RA-sensitive and trans-RA-resistant breast cancer cell lines. Our results demonstrate that RXR-selective retinoids, particularly in combination with RAR-selective retinoids, could significantly induce RARbeta and inhibit the growth and induce the apoptosis of trans-RA-resistant, RAR alpha-deficient MDA-MB-231 cells but had low activity against trans-RA-sensitive ZR-75-1 cells that express high levels of RAR alpha. Using gel retardation and transient transfection assays, we found that the effects of RXR-selective retinoids on MDA-MB-231 cells were most likely mediated by RXR-nur77 heterodimers that bound to the RA response element in the RARbeta promoter and activated the RARbeta promoter in response to RXR-selective retinoids. In contrast, growth inhibition by RAR-selective retinoids in trans-RA-sensitive, RAR alpha-expressing cells most probably occurred through RXR-RAR alpha heterodimers that also bound to and activated the RARbeta promoter. In MDA-MB-231 clones stably expressing RAR alpha, both RARbeta induction and growth inhibition by RXR-selective retinoids were suppressed, while the effects of RAR-selective retinoids were enhanced. Together, our results demonstrate that activation of RXR can inhibit the growth of trans-RA-resistant MDA-MB-231 breast cancer cells and suggest that low cellular RAR alpha may regulate the signaling switch from RAR-mediated to RXR-mediated growth inhibition in breast cancer cells.

Sleep and gastric function in irritable bowel syndrome: derailing the brain-gut axis

BACKGROUND

Recently, several studies have shown an alteration in bowel function during sleep in patients with irritable bowel syndrome (IBS), and a recent study also suggests a remarkable increase in rapid eye movement (REM) sleep. These studies have suggested that an alteration in CNS function may play an important role in the pathogenesis of IBS.

AIMS

To confirm the presence of an alteration in REM sleep in patients with IBS and to assess the relation between sleep and a non-invasive measure of gastric functioning, the electrogastrogram (EGG).

PATIENTS

Ten patients with IBS and 10 age and sex matched normal volunteers.

METHODS

All subjects slept one night in the sleep laboratory and underwent polysomnographic monitoring to determine sleep patterns, and recording of the EGG from surface electrodes.

RESULTS

The IBS group had a notable and significant increase in the percentage and duration of REM sleep (p < 0.05). The control group had a decrease in the amplitude of the dominant EGG frequency from waking to non-REM sleep (p < 0.05), and a subsequent increase in the amplitude from non-REM to REM sleep (p < 0.05). No such changes were noted in the patients with IBS.

CONCLUSIONS

Results confirmed the enhancement of REM sleep in patients with IBS and suggested an intrinsic alteration in autonomic and CNS functioning in patients with IBS.

[Changes of concentrations of umbilical blood monoamines in low birth weight infant and their clinical significance]

OBJECTIVE

To investigate the changes of concentrations of umbilical blood monoamines in low birth weight (LBW) infants and their clinical significance.

METHODS

By fluorescence spectrophotometry, the concentrations of umbilical plasma norepinephrine (NE), dopamine (DA), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in 18 LBW before and after delivery were measured and compared with 20 normal birth weight (NBW) infants.

RESULTS

The concentration of all monoamines, especially of the 2 catecholamines, i.e. NE and DA, were markedly lower in LBW than that in NBW (P < 0.05-0.01), regardless of prepartus or postpartus; the concentrations of all monoamines in postpartal umbilical plasma in both of LBW and NBW were higher than those in prepartal, and the increase of NE in NBW showed significant difference (P < 0.05).

CONCLUSIONS

The decrease of all monoamines, especially of catecholamines in LBW could be one of the reasons causing the increase of mortality and the decrease of mental and physical development in LBW.

[DNA polymorphism analysis by capillary electrophoresis]

A review is given here to describe the principle and methods of gene polymorphism analysis by capillary electrophoresis (CE). DNA length polymorphism and sequence polymorphism are very important phenomena in gene molecular biology. Some practical works of gene length polymorphism analysis and sequence polymorphism analysis are listed. SSCP and HPA methods detecting gene point mutations are demonstrated. Applications of gene polymorphism analysis by CE in clinical, forensic and biological research are also discussed in this paper.