The detection of simian virus 40 in human tumors by polymerase chain reaction

Simian virus (SV) 40 is a deoxyribonucleic acid (DNA) virus that induces mesotheliomas, ependymomas, bone tumors, and lymphomas in hamsters. In recent years SV40 sequences have been detected in approximately 60% of mesotheliomas and ependymomas, in 33% of bone tumors and sarcomas, and in 13% of lymphomas. Because the amount of human specimens available for molecular studies is usually minimal, the method most commonly used to demonstrate SV40 in human specimens is the polymerase chain reaction (PCR). PCR is a highly sensitive and useful technique. In the PCR reaction, different sets of primers are used for targeting different regions of DNA. The regions of the SV40 genome targeted by PCR include the large T-antigen, the small t-antigen, the origin of replication, and viral protein-1 capsid protein. The use of these different sets of primers to test human tumor specimens for SV40 produce a different percentage of positive results. This is because these experiments revealed that some primers are more specific than others which may also detect sequences belonging to other DNA papovaviruses. Therefore, the combined use of different sets of primers is recommended when it is important to distinguish SV40 from other related papovaviruses such as BK and JC, which can also be occasionally present in human cells. Furthermore, these experiments demonstrated that polymerase chain reaction analyses for simian virus 40 can be performed better and easier when using deoxyribonucleic acid extracted from fresh and/or frozen tissue. Deoxyribonucleic acid from paraffin embedded specimens should not be used routinely for simian virus 40 testing because of the high risk of obtaining false negative results. However, these paraffin derived deoxyribonucleic acids can be used reliably in molecular laboratories specialized in these type of analyses. This paper describes the methods that we have developed to test simian virus 40 in human specimens.

Alpha-tocopherol prevents ethanol-induced elevation of [Ca2+]i in cultured canine cerebral vascular smooth muscle cells

Exposure of cultured canine cerebral vascular smooth muscle cells to ethanol (10-400 mM) for 1-5 days results in concentration-dependent elevation in resting intracellular free calcium ([Ca2+]i) levels. Preincubation of these cultured vascular cells with alpha-tocopherol (20 microM), alone, did not produce any apparent changes from control resting levels of [Ca2+]i. However, after concomitant addition of alpha-tocopherol (20 microM) and ethanol (10-400 mM), the rises of [Ca2+]i induced by ethanol were attenuated markedly. These results suggest that alcohol-induced lipid peroxidation of cerebral vascular muscle cell membranes triggers membrane entry of extracellular Ca2+, which could play an important role in ethanol-induced cerebrovasospasm, brain ischemia and stroke. Moreover, these new results support the concept recently advanced to suggest that alpha-tocopherol-induced amelioration of membrane lipid alterations of cerebral vascular cells can prevent ethanol-induced excessive accumulation of [Ca2+]i.

Mechanisms of hydrogen peroxide-induced contraction of rat aorta

It has been suggested that reactive oxygen species may be involved in the regulation of vascular tone. However, the underlying mechanisms remain to be elucidated. The present studies were designed to investigate the contractile effects of hydrogen peroxide (H2O2), one of the reactive oxygen species, on isolated ring segments of rat aorta with and without endothelium. H2O2 induced an endothelium-independent contraction in isolated rat aorta ring segments in a concentration-dependent manner at concentrations from 5 x 10(-6) to 5 x 10(-3) M. H2O2-induced contractions of denuded rat aorta rings were stronger than those on intact rat aorta segments. The contractile effects of H2O2 were inhibited completely by 1200 u/ml catalase. The presence of 1.0 microM Fe2+ or 10 microM proadifen, a cytochrome P450 monooxygenase inhibitor, potentiated the contractile effect of H2O2 on isolated rat aorta segments. 1 mM deferoxamine (a Fe2+ chelator) or 100 microM dimethyl sulfoxide (a hydroxyl radical scavenger) significantly attenuated the vessel contractions induced by hydrogen peroxide plus Fe2+ or hydrogen peroxide itself. Removal of extracellular Ca2+ ([Ca2+]0), addition of 5 microM verapamil, administration of a protein kinase C inhibitor (staurosporine), treatment with an inhibitor of protein tyrosine phosphorylation (genistein) or employment of 5.0 microM indomethacin resulted in a significant attenuation of the contractile responses of the vessels to H2O2. Pharmacological antagonists (e.g. a muscarinic acetylcholine receptor antagonist (atropine), an antagonist of histamine H1 receptors (diphenhydramine), an antagonist of histamine H2 receptors (cimetidine), an alpha-adrenoceptor antagonist (phentolamine), a beta-adrenoceptor antagonist (propranolol) and an antagonist of serotonin receptor (methysergide)) did not inhibit or attenuate the contractions induced by H2O2. Exposure of primary aortic smooth muscle cells to H2O2 (5 x 10(-6) to 5 x 10(-3) M) produced significant rises of intracellular Ca2+ ([Ca2+]i) within 20 s. Employment of 1.0 microM Fe2+ markedly enhanced the increment in [Ca2+]i in the smooth muscle cells. 10 microM proadifen treatment failed to alter the hydrogen peroxide-induced increment in [Ca2+]i of the smooth muscle cells. However, the presence of 5 microM indomethacin significantly attenuated the rise in [Ca2+]i in smooth muscle cells. The present results suggest that H2O2 can induce contractions of rat aorta segments, at pathophysiological concentrations, which are Ca2+-dependent. Hydroxyl radicals (.OH), cyclooxygenase products, protein kinase C and products of protein tyrosine phosphorylation appear to play some role in hydrogen peroxide-induced contractions. Metabolites catalyzed by cytochrome P450-dependent enzymes (upon treatment with hydrogen peroxide) appear to exert a vasodilator effect on rat aorta segments. Lastly, some unidentified mediators, produced by a cytochrome P450 inhibitor (proadifen), during hydrogen peroxide treatment, appear to play some role in contraction of vascular smooth muscle of rat aorta segments in vitro.

[Study on inhibition and prevention of tumor and antioxidative effects of lithium carbonate in tumor bearing mice]

Two Kinds of tumor-bearing mice (hepatoma H22 and sarcoma S180) were administered with lithium carbonate (Li2CO3) for 17 or 10 days (advanced and simultaneous administration), in order to observe the effects of prevention and treatment of Li2CO3 on malignant tumor, as well as the relationship between Li2CO3 and lipid peroxidation in tumor-bearing mice. Meanwhile, we compared the toxic and side effects of cyclophosphamide (CP) with that of Li2CO3. The results showed that Li2CO3 had no significant toxic or side effects with the suggested doses. In the tests of inhibition and prevention of tumor, Li2CO3 could significantly inhibit the grouth of the two kinds of tumor, and increase the activity of superoxide dismutage (SOD) and decrease the contents of Malonyldialdehyde (MDA). In addition, Li2CO3 had no effect on the white blood cells (WBC) and decreased the micronucleus frequency (MNF) in bone marrow polychromatic erythrocytes (PCE), while CP had definite effect of decreasing the WBC and increasing the MNF in the tumor-bearing mice.

Molecular cytogenetic analysis of patients with holoprosencephaly and structural rearrangements of 7q

The holoprosencephaly (HPE) sequence is a malformation complex with abnormal midline cleavage of the embryonic forebrain. HPE is genetically heterogeneous with at least 6 different chromosome regions containing genes involved in the expression of the phenotype. HPE3, recently identified as the human Sonic hedgehog gene, is localized to 7q36. We have used fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) amplification in 5 cell lines from patients with HPE (3 cases), HPE and sacral agenesis (1 case), and microcephaly (1 case) to further define the structural rearrangements of the long arm of chromosome 7 in each case. All cell lines demonstrated loss of material in the critical region of HPE3 at band 7q36, which includes the Sonic hedgehog gene. We report here the analysis of these patient cell lines.

[Detection and enrichment of fetal cells in maternal circulation for prenatal diagnosis of fetal sex]

OBJECTIVE

To study fetal cells from maternal peripheral blood for prenatal diagnosis of fetal sex.

METHODS

Samples of peripheral blood in 64 women of 8-40 gestational weeks were collected to enrich the fetal nucleated red blood cells by density gradient centrifugation. DNA was extracted from each samples of enriched fetal cell for PCR amplification of Y chromosome specific DNA to determine fetal sex.

RESULTS

Fetal nucleated red cells were found in 25 out of 64 maternal samples (39.06%). Y chromosome 149 bp was found in 28 cases of the 33 mothers given birth to male babies. One Y specific DNA sequence was detected in 31 women had female babies. The sensitivity was 84.85% and specificity 96.77%. The overall agreement of the diagnosis was 90.63%.

CONCLUSION

Density gradient centrifugation can enrich fetal nucleated red blood cells from maternal peripheral blood. Fetal sex can be determined by PCR amplification of Y chromosome specific DNA with these fetal cells.

Alcohol-induced vascular damage of brain is ameliorated by administration of magnesium

Ethanol ingestion can cause irreversible neuronal and vascular damage in the brain and stroke-like events. Using an intact in vivo rat brain (pial) model, TV image-intensification, cultured cerebral vascular muscle cells, digital-image analysis, and a novel Mg2+ ion-selective electrode to measure extracellular ionized Mg2+, studies were designed to determine whether: 1) perivascular or systemic administration (i.v. or intra-arterial) of magnesium aspartate HCI (MgA) exert vasodilator effects on arterioles (65-130 microm o.d.) and venules (60-135 microm); 2) nonvasodilator doses of MgA could modify vascular spasms induced by BaCl2 and ethanol; 3) nonvasodilator doses of MgA could ameliorate or prevent the cerebral vascular damage induced by high doses of ethanol; and 4) ethanol depletes cerebral vascular muscle of intracellular Mg ions ([Mg2+]i). Perivascular application of MgA (0.01-100 micromol) produced dose-dependent vasodilatation of cerebral arterioles and venules; arterioles yielded greater vasodilator responses compared to venules. Nonvasodilator doses of Mg (1.0, 4.0 micromol/min), administered i.v. or intra-arterially, into a branch of the internal carotid artery, prevented: 1) the spasmogenic actions of ethanol and Ba2+; and 2) the vasculotoxic actions (rupture of postcapillary venules and focal hemorrhages) of ethanol. In addition, ethanol depleted cerebral vascular muscle cells of [Mg2+]i; blood levels of ionized Mg2+ rose after IP ethanol. Despite the fact that systemic infusion of low nonvasodilator doses did not result in dilatation of the pial arterioles and venules, plasma total and ionized Mg rose 18-230%, depending upon dose of MgA and time of plasma sampling. These data support the idea that Mg2+ can act as a local vasodilator on brain microvessels and possess antispasmodic properties on brain arterioles and venules. In addition, our results indicate that Mg may possess some unique cerebral vascular protective properties against the vasculotoxic effects of ethanol. Lastly, these findings suggest ethanol-induced cerebrovasospasm and vascular damage appear to be associated with a rapid loss of [Mg2+]i from cerebral vascular muscle cells.

[The ultraviolet spectra of alpha,alpha'-dioxoketene cyclic S,S-acetals(N,N-acetals)]

In this paper, the ultraviolet spectra of alpha,alpha'-dioxoketene cyclic S,S-acetals (N,N-acetals) have been studied and their changing characters with the change of chemical structure have been indicated.

Staurosporine and H7 attenuate ethanol-induced elevation in [Ca2+]i in cultured canine cerebral vascular smooth muscle cells

Chronic exposure of cultured canine cerebral vascular smooth muscle cells to ethanol (10-400 mM) for 1-5 days resulted in significant concentration-dependent elevation in resting intracellular free calcium ([Ca2+]i) levels. Preincubation of these cultured vascular cells with inhibitors of protein kinase C (PKC), staurosporine and H7, induced no apparent changes from the control resting levels of [Ca2+]i. However, the increases of [Ca2+]i due to ethanol treatment were attenuated markedly by staurosporine and H7. Our data suggest that activation of PKC plays an important role in ethanol's action in producing a sustained rise in [Ca2+]i in cerebral vascular smooth muscle cells. Activation of PKC could thus play a crucial role in the pathogenesis of alcohol-induced cerebral ischemia and stroke.

[Influence of cerebral traumatic dementia treated with acupuncture at houxi and shenmen]

Sixty-two cerebral traumatic dementia patients were randomly divided into two groups acupuncture treatment group (Group A, 32 cases) and physical treatment group (Group B, 30 cases). The changes of MMSE scores and auditory P300 were observed before and after the treatment. It were found that the indexes in group A changed significantly (P < 0.05-0.001), and the indexes in group B didn't change significantly (P > 0.1-0.4). The therapeutic effect in group A was better than that in group B(P < 0.001). The results confirmed that the cognitive function of cerebral traumatic dementia patients was increased effectively with acupuncture at Houxi and Shenmen.

Genomic DNA from mice: a comparison of recovery methods and tissue sources

Our aim is to identify an extraction method and the source of mouse tissue(s) that could allow a high-resolution genomic scan from a living mouse. We compared and optimized two methods for yield, purity of DNA, and their use in the polymerase chain reaction (PCR) of DNA extracted from different mouse tissues. In addition to whole blood, tissue samples from the brain, liver, testis, and tail were included in this study. The Rapid Method (RM) is preferable for the whole blood samples and testis and brain tissue samples because it is quicker, less toxic, and more cost-effective than the proteinase K method (PM). For liver the PM produced higher yields of DNA with less degradation than the RM. For tail tip, the PM produced a higher yield of DNA, but the RM resulted in a higher yield of PCR product. From a living mouse, a tail snip generated a sufficient amount of DNA for several hundred PCRs but not a complete genomic scan. We suggest that the RM can be used to extract genomic DNA for a complete genomic scan which requires either testicular tissues or repeated blood samples from the suborbital sinus over several months without sacrificing the animal.

Exposure of piglet coronary arterial muscle cells to low concentrations of Mg2+ found in blood of ischemic heart disease patients result in rapid elevation of cytosolic Ca2+: relevance to sudden infant death syndrome

Exposure of cultured piglet primary neonatal coronary arterial smooth muscle cells to concentrations of ionized Mg2+ ([Mg2+]o (i.e., 0.48, 0.3, 0.15 mM) found in blood of patients presenting with ischemic heart disease and in hypoxic neonates resulted in concentration-dependent elevation in intracellular free Ca2+ ions ([Ca2+]i; the lower the [Mg2+]o, the higher the [Ca2+]i rise. The lowest concentration of [Mg2+]o tested, i.e., 0.15 mM, resulted in a clear rounding-up (i.e., contraction) of many of the coronary smooth muscle cells; reintroduction of normal 1.2 mM [Mg2+]o failed to restore either normal [Ca2+]i or cell shape.

[The value of blood sedimentation test in early diagnosis of amniotic fluid embolism]

OBJECTIVE

To explore the value of peripheral blood sedimentation in early diagnosis of amniotic fluid embolism.

METHOD

The contents of amniotic fluid were detected with blood sedimentation test in 15 cases of amniotic fluid embolism and 100 cases of normal pregnant women.

RESULTS

The contents of amniotic fluid including particles of vernix caseasa, lanugo hair and epithelium cells were found in serum of amniotic fluid embolism cases but not found in cases of normal pregnant women.

CONCLUSION

It suggested that the blood sedimentation test would be valuable for early diagnosis of amniotic fluid embolism.

Measurement of sodium fluorescein wash-in time constants in subjects with peripheral vascular disease

The authors developed a noninvasive two-channel dynamic dermofluorometer that can quantitatively follow the rapid skin wash-in kinetics of a fluorescent dye to provide an assessment of local skin perfusion. The dermofluorometer was tested in normal subjects and diabetic patients with and without peripheral vascular disease. After an intravenous injection of 1-2 mL of a 10% solution of sodium fluorescein (1.1-2.8 mg/kg), the fluorescent signal was monitored from two sites on the skin surfaces of the forearm and foot. A 3.2-mm-diameter glass fiberoptic bundle was used both to transmit the excitation light (489 nm) and to receive the fluorescent emission (517 nm). Dermofluorometer readings were recorded approximately every second for 10-15 minutes following the injection. The time course of the fluorescein signal intensity was fit to a single exponential curve characterized by a wash-in time constant. There was no significant difference in arm wash-in time constants. Foot wash-in time constants were increased in diabetic patients who had past histories of foot ulcers relative to diabetic patients without a history of foot ulcers (3.2 vs 1.6 min., p < 0.05). Foot wash-in time constants were decreased in diabetic patients who had active infected foot ulcers. This study demonstrates the ability of the dynamic dermofluorometer to measure wash-in constants that reflect the local skin perfusion in less than 15 minutes after a low intravenous dose of sodium fluorescein.

[Detection of hepatitis B virus (HBV) DNA in renal biopsied tissues from patients with HBV related glomerulonephritis using molecular biology techniques]

The purpose of this study was to determine the pathogenesis of hepatitis B virus (HBV) related glomerulonephritits. Measurement of HBV DNA was performed in paraffin-embedded renal biopsied tissues from 20 patients with HBV related glomerulonephritis by using in situ hybridization (ISH) with digoxigenin-labelled probe and in situ polymerase chain reaction (IS-PCR). HBV DNA staining was detected in 17 out of 20 patients (85%) with probe of full-length HBV DNA and in 14 out of 17 patients (82.35%) with a probe of S + C segments of HBV DNA. 17 out of 20 patients (85%) were also positive by IS-PCR assay. HBV DNA positive particles were diffusely distributed in glomerular capillary loops, mesangial areas, renal tube, and they were mainly in the presentation of cytoplasm-nucleus and nucleus. The distribution of HBsAg detected by immunohistochemical technique (LSAB assay) coincided with that of HBV DNA. It is suggested that renal lesions due to HBV are not only the results of immunologic response, but also the outcome of direct invasion of HBV to this organ. Our study provided new evidence on the molecular mechanism level for the research of the pathogenesis in HBV related glomerulonephritis.

[Study on antimutagenic effect of lanthanum carbonate in CA test, UDS test and MN test]

Antimutagenic effect of Lanthanum carbonate [La2 (CO3)3] has been evaluated by means of unscheduled DNA synthesis (UDS) test, chromosomal aberration (CA) test in vitro human embryofibroblast (HEF) and micronucleus (MN) test in mouse bonemarrow polychromatic erythrocyte (PCE) induced by four different mutagens, i.e., short wave ultraviolet (UV), hydrochloric acid nitrogen mustard (NH2HCl), arsenic sodium oxide (NaAsO2) and cyclophosphamide (CP). The results of this study indicated that the antimutagenic effect of La2(CO3)3 was obvious in multiple antimutagenic systems in which mutation was induced by UV, NH2HCl and CP, but the effect of La2(CO3)3 on the decrease of CA frequencies induced by NaAsO2 had no statistical significance.

Short-term reduction in dietary intake of magnesium causes deficits in brain intracellular free Mg2+ and [H+]i but not high-energy phosphates as observed by in vivo 31P-NMR

31P-NMR spectroscopic studies were performed in vivo on brains of rats fed 30-35% normal dietary Mg intake for 6 weeks. Within 2 weeks of the moderately restricted Mg diet serum Mg fell 50%, and brain intracellular free [Mg2+]i fell 15%; within 3 weeks of restricted diet, brain [Mg2+]i fell 40% and remained at this level for the additional 3 weeks. Intracellular pH (pH[i]) progressively rose in a reciprocal manner for 4 weeks. At no interval of time did brain phosphocreatine (PCr), [ATP], or inorganic phosphate change despite the fall in brain [Mg2+]i, brain pH(i) and serum Mg. The Mg-deficiency-induced cytosolic loss of protons (resulting in an alkaline cytosol) could be a compensatory mechanism to stabilize [PCr], [ATP] and [ADP] levels via creatine kinase, thus maintaining cytosolic phosphorylation potential. The rise in pH(i) associated with Mg-deficiency would also account for increased cerebral vascular muscle contractility under these conditions. Lastly, these studies indicate that brain [Mg2+]i may change without a concomitant change in cell [ATP], and that brain [Mg2+]i may be a useful marker for total body Mg2+ status.

Effects of cholinergic and alpha-adrenergic agonists on the monovalent ion content of rat submandibular gland acinar cells studied by X-ray microanalysis

The effects of cholinergic and alpha-adrenergic stimulation (in vivo and in vitro) on the monovalent ion content of rat submandibular gland acinar cells were evaluated at the subcellular level by X-ray microanalysis. Fragments of glands or enzymatically dispersed acini were slam-frozen and cut into ultrathin cryosections. Spectra were collected from secretory granules, nucleus, the basal cytoplasm containing endoplasmic reticulum and the apical cytoplasm identified between secretory granules. No significant changes in Na and Cl content were observed after the isolation of acini, but the K concentration decreased compared with cells from in situ glands. The Cl and K content in all four compartments studied decreased significantly after cholinergic stimulation both in vivo and in vitro but in a more restricted fashion after alpha-adrenergic stimulation. Our findings indicate that: (1) the physiological mechanisms regulating the monovalent ion composition of submandibular cells are relatively well preserved in isolated acinar cells; (2) the results from in vivo experiments are in good agreement with those from in vitro experiments; and (3) the effects of cholinergic and alpha-adrenergic stimulation on the K+ and Cl- efflux at the subcellular level are similar but the response is generally less with alpha-adrenergic stimulation.

Purification, identification, concentration and bioactivity of (Z)-7-dodecen-1-yl acetate: sex pheromone of the female Asian elephant, Elephas maximus

In their natural ecosystems, adult male and female Asian elephants, Elephas maximus, live separately. For several weeks prior to ovulation, female elephants release a substance in their urine which elicits a high frequency of non-habituating chemosensory responses, especially flehmen responses, from male elephants. These responses occur prior to, and are an integral part of, mating. Using bioassay-guided fractionation, quantitatively dependent on these chemosensory responses, a specific sex pheromone was isolated and purified by an alternating series of organic and/or aqueous extractions, column chromatography, gas chromatography and high-performance liquid chromatography. Using primarily 1H-proton nuclear magnetic resonance (NMR) spectrometry and gas chromatography-mass spectrometry (GC-MS) of the urine-derived pheromone and its dimethyl disulfide derivative, we determined the structure of the active compound to be (Z)-7-dodecen-1-yl acetate (Z7-12:Ac). Concentrations of Z7-12:Ac in the female urine increased from non-detectable during the luteal phase to 0.48 microgram/ml (0.002 mM) early in the follicular phase and to 33.0 micrograms/ml (0.146 mM) just prior to ovulation. Bioassays with commercially available authentic synthetic Z7-12:Ac, using 10 Asian male elephants at several locations in the US, demonstrated quantitatively elevated chemosensory responses that were robust during successive tests, and several mating-associated behaviors. Bioassays with Z7-12:Ac with adult male elephants dwelling in more natural social situations in forest camps in Myanmar revealed some differing contextual pre-mating behavioral components. The remarkable convergent evolution of this compound suggests that compounds identified in mammalian exudates that are also present in pheromone blends of insects should be re-evaluated as potential mammalian chemosignals.

A small, stable RNA induced by oxidative stress: role as a pleiotropic regulator and antimutator

Exposure of E. coli to hydrogen peroxide induces the transcription of a small RNA denoted oxyS. The oxyS RNA is stable, abundant, and does not encode a protein. oxyS activates and represses the expression of numerous genes in E. coli, and eight targets, including genes encoding the transcriptional regulators FhlA and sigma(S), were identified. oxyS expression also leads to a reduction in spontaneous and chemically-induced mutagenesis. Our results suggest that the oxyS RNA acts as a regulator that integrates adaptation to hydrogen peroxide with other cellular stress responses and helps to protect cells against oxidative damage.

Low levels of serum ionized magnesium are found in patients early after stroke which result in rapid elevation in cytosolic free calcium and spasm in cerebral vascular muscle cells

Ninety-eight patients admitted to the emergency rooms of three urban hospitals with a diagnosis of either ischemic stroke or hemorrhagic stroke exhibited early and significant deficits in serum ionized Mg2+ (IMg2+), but not total Mg, as measured with a unique Mg2+-sensitive ion-selective electrode. Twenty-five percent of these stroke patients exhibited >65% reductions in the mean serum IMg2+ found in normal healthy human volunteers or patients admitted for minor bruises, cuts or deep lacerations. The stroke patients also demonstrated significant elevation in the serum ionized Ca2+ (ICa2+)/IMg2+ ratio, a sign of increased vascular tone and cerebrovasospasm. Exposure of primary cultured canine cerebral vascular smooth muscle cells to the low concentrations of IMg2+ found in the stroke patients, e.g. 0.30-0.48 mM, resulted in rapid and marked elevations in cytosolic free calcium ions ([Ca2+]i) as measured with the fluorescent probe, fura-2, and digital image analysis. Coincident with the rise in [Ca2+]i, many of the cerebral vascular cells went into spasm. Reintroduction of normal extracellular Mg2+ ion concentrations failed to either lower the [Ca2+]i overload or reverse the rounding-up of the cerebral vascular cells. These results suggest that changes in Mg2+ metabolism play important roles in stroke syndromes and in the etiology of cerebrovasospasm associated with cerebral hemorrhage.

Chronic treatment of cultured cerebral vascular smooth cells with low concentration of ethanol elevates intracellular calcium and potentiates prostanoid-induced rises in [Ca2+]i: relation to etiology of alcohol-induced stroke

The influence of chronic treatment of cultured canine cerebral vascular smooth muscle cells, with low concentrations of ethanol, on the intracellular concentrations of free calcium ([Ca2+]i) was studied by use of the fluorescent indicator, fura-2, and digital imaging microscopy. The resting level of [Ca2+]i in the cerebral vascular smooth muscle cells was 89 +/- 3.2 nM. Exposure of these cells to 10 and 25 mM ethanol for 5 days resulted in significant elevation of [Ca2+]i (mean rises to 208 +/- 11.4 and 307 +/- 14.0 nM, respectively), and potentiated the transient rise in [Ca2+]i induced by 10(-7) M PGF2 alpha. However, exposure of these cerebral cells to a high-concentration ethanol (100 mM) resulted in only a slight increase of [Ca2+]i (106 +/- 6.9 nM) and lack of effects on the [Ca2+]i response to PGF2 alpha. Irrespective of the different ethanol treatments, the subcellular distribution of [Ca2+]i was heterogeneous in all the cells tested. Our data suggest that chronic exposure of cerebral vascular smooth muscle cells to ethanol, particularly at low concentrations, results in dramatic increases in [Ca2+]i and the responses of these vascular smooth muscle cells to prostanoids. These results support an hypothesis whereby ethanol induces stroke by causing spasm and rupture of cerebral blood vessels as a consequence of large rises in intracellular Ca2+.

Elevation of extracellular magnesium rapidly raises intracellular free Mg2+ in human aortic endothelial cells: is extracellular Mg2+ a regulatory cation?

Extracellular magnesium ions [Mg2+]o are known to regulate functions of endothelial cells, but whether [Mg2+]o can alter intracellular free ionized magnesium [Mg2+]i in these cells remains unknown. The present studies, using digital imaging microscopy and the Mg2+ fluorescent probe, mag-fura-2, determined effects of elevation of [Mg2+]o on [Mg2+]i in cultured human aortic endothelial cells. With normal Mg2+(1.2 mM)-containing incubation media, [Mg2+]i was 0.51+/-0.04 mM with a heterogeneous distribution. The ratio of [Mg2+]i/[Mg2+]o was 0.52+/-0.07. Elevation of [Mg2+]o up to 4.8 mM increased [Mg2+]i to 0.80+/-0.07 mM in 2-10 min and lowered the ratio of [Mg2+]i/[Mg2+]o to 0.16+/-0.02. Irrespective of the observed increments of [Mg2+]i, a subcellular heterogeneous distribution of [Mg2+]i was always evident in all cells tested. Our results suggest that [Mg2+]o can regulate [Mg2+]i more rapidly than heretofore believed, supporting the hypothesis that extracellular Mg2+ can exert regulatory effects on endothelial cell functions and probably act as extracellular regulatory cations