CDK4 amplification is an alternative mechanism to p16 gene homozygous deletion in glioma cell lines

Recently, it has been shown that a gene encoding the cyclin-dependent kinase 4 inhibitory protein, p16, is frequently targeted for homozygous deletions in several types of tumor cell lines, including those established from malignant gliomas. Here we have examined 32 glioma cell lines for amplification-associated overexpression of the CDK4 gene as an alternative mechanism for abrogating the growth-regulatory effects of p16. Two of the cell lines revealed high-level expression of CDK4 in association with gene amplification, and this alteration was observed among the 10 cases having intact p16 genes. Consequently, 24 of 32 glioma cell lines revealed one of two alternative genetic alterations, each of which indicates that increased cdk4 kinase activity is important to glial tumor development.

Chemical and mutagenic patterns of airborne particulate matter collected in 17 Italian towns

The mutagenicity of airborne particulate matter collected in 17 towns of Italy in 1990 was assessed using the Ames test. The mutagenicity of crude extract correlated with amount of lead, suggesting the direct contribution of gasoline car exhausts. Moreover, the mutagenicity correlated with particulate matter amounts. An inverse correlation with temperature was observed. The crude extracts were fractionated in acid, basic, and neutral fractions. The latter was further separated into polycyclic aromatic hydrocarbon (PAH), polar, and nonpolar fractions. Acid and polar fractions showed the higher mutagenicity. Average recovery of mutagenicity was about 60%.

Blood flow velocity in common carotid artery in humans during breath-holding and face immersion

Blood flow velocity was measured in the common carotid artery of humans during breath-holding (BH) in the supine and upright positions, and during breath-hold face immersion (FIBH) in cold (20 degrees C) and warm (35 degrees C) water in the upright position with 90 degrees flexion of the upper body, to test the influences of the body position, facial immersion and temperature on changes in cerebral blood flow. Simultaneously, the heart rate (HR) and blood pressure (BP) under the same conditions, and the end-tidal PO2 and PCO2 (PETO2 and PETCO2) during supine BH, were also measured. Results showed that posture had no significant effect on the apneic HR. Bradycardia developed during cold FIBH, but not warm FIBH. The BP increased during BH in both positions, and during both cold and warm FIBH. The PETO2 decreased and the PETCO2 increased significantly at the end of BH. The blood velocity decreased transiently at the beginning of upright BH, but increased time-dependently during both supine and upright BH. Moreover, the velocity increased more during warm FIBH than during BH's, and even more during cold than warm FIBH. When bradycardia occurred during cold FIBH, the velocity integral per minute tended to decrease. These results suggest that the cerebral blood flow increases in these conditions of BH. This increase can be explained by the increase in PETCO2 and decrease in PETO2, possibly with a slight contribution from the increase in the BP.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of glioma cell lines for amplification and overexpression of MDM2

Recently, amplification of the gene encoding a p53 binding protein, MDM2, was determined in 8% of the cases constituting a large series of glioblastomas. Here we have utilized Southern blot analysis to examine 30 cell lines established from such tumors, and our investigation has revealed large increases in MDM2 gene dosage in two cases, one of which showed coamplification of the CDK4 gene that resides in close proximity to MDM2 in chromosomal region 12q13-14. Northern analysis demonstrated overexpression of MDM2 mRNA in the two cell lines with gene amplification, and overexpression of MDM2 protein was evident in each of these by immunohistochemical and Western blot analysis. Analysis of TP53 cDNAs revealed normal TP53 sequences in the cell lines with MDM2 amplification; these results are consistent with those of previous studies suggesting that MDM2 amplification occurs only in tumors expressing wild-type p53. In total, these data suggest that MDM2 amplification in glioblastoma cell lines occurs at a frequency (6.7%) comparable to that determined in primary tumors; occurs in cell lines expressing wild-type p53; and can involve the coamplification of additional genes.

Flow velocity in carotid artery in humans during immersions and underwater swimming

Heart rate and flow velocity in the common carotid artery were examined on eight subjects in various underwater conditions. The heart rate decreased more markedly during whole-body immersion than during head-out immersion. The end-diastolic flow velocity and the flow-velocity integral in a cardiac cycle during whole-body immersion increased more markedly than during head-out immersion. Differences in heart rate and flow velocity were not detected between sitting and prone positions in whole-body immersion. Heart rate increased at the beginning and after underwater swimming. The peak systolic flow velocity increased significantly after the end of underwater swimming. The flow-velocity integral in a cardiac cycle decreased during underwater swimming, but in a minute did not change significantly. These results suggest that facial immersion is important in eliciting pronounced carotid artery flow-velocity response in addition to the heart-rate response and that underwater exercise influences these responses. However, underwater posture apparently does not influence them.

Short- and long-term prognosis after acute myocardial infarction in Chinese men and women

Most, but not all, studies in Western countries have indicated that women have a higher mortality than men after an acute myocardial infarction, but this has not been well documented in the developing world. The authors studied 601 male and 294 female myocardial infarction patients, aged 26-94 years, admitted to a city hospital in Beijing, China, between 1974 and 1986. A total of 745 (98.8%) of the cohort of 754 who survived past their initial hospitalization were followed up in 1988. Compared with their male counterparts, female myocardial infarction patients were older (63.4 vs. 58.1 years) and had a higher prevalence of tachycardia (heart rate, > or = 110 beats/minute), rales, New York Heart Association class III or IV, and heart block, but a lower prevalence of smoking and white collar occupation (all p < 0.01). The mortality within 28 days of their myocardial infarction was higher in women than in men, mainly in the group whose age was less than 60 years (20.4% vs. 7.1%, p < 0.001). The greater risk of short-term mortality in women persisted even after adjustment for age, history of stroke and hypertension, tachycardia on admission, anterior infarction, Killip class III or IV, and arrhythmia (relative odds = 1.74, 95% confidence interval 1.17-2.60). The 10-year total cumulative mortality in persons who survived the first 28 days following their myocardial infarction was 51.1% for women and 35.9% for men (log rank p = 0.002). After adjustment for age, this difference was not statistically significant (p = 0.3). Our results suggest that, in Beijing, women have a higher short-term mortality after myocardial infarction compared with men.

Correction of accelerated autoimmune disease by early replacement of the mutated lpr gene with the normal Fas apoptosis gene in the T cells of transgenic MRL-lpr/lpr mice

MRL-lpr/lpr mice develop a generalized autoimmune disease which includes increased autoantibody production, glomerulonephritis, and development of lymphadenopathy. The lpr genetic defect has been identified as a mutation in the Fas apoptosis gene that results in low expression of Fas mRNA. To determine the significance of the lpr mutation and T cells in the development of the autoimmune disease, we constructed transgenic MRL-lpr/lpr mice using a full-length murine Fas cDNA under the regulation of the T-cell-specific CD2 promoter and enhancer. Here we show that the early correction of the lpr gene defect in T cells eliminates glomerulonephritis and development of lymphadenopathy and decreases the levels of autoantibodies. In this model, early correction of the lpr defect in T cells is sufficient to eliminate the acceleration of autoimmune disease even in the presence of B cells and other cells that express the mutant lpr gene.

Expression of hepatitis E virus putative structural proteins in recombinant vaccinia viruses

Hepatitis E virus (HEV) is a polyadenylated, positive-stranded RNA virus which is a major cause of enterically transmitted non-A, non-B hepatitis in many developing countries. The viral genome contains three different open reading frames (ORFs): ORF1, which is believed to encode nonstructural proteins, and ORF2 and ORF3, which are believed to encode structural proteins. The full-length putative structural proteins encoded by ORF2 and ORF3 of HEV have been cloned and expressed in recombinant vaccinia virus. Proteins encoded by ORF2 and ORF3 when expressed in vaccinia virus are recognized by pooled sera obtained from individuals with acute hepatitis E. Vaccinia-expressed viral gene products of HEV will have utility in characterizing the cell-mediated immune response to HEV.

Body mass and blood pressure in a lean population in southwestern China

Body mass has been consistently associated with blood pressure in acculturated populations but not in lean populations with low blood pressures. In southwestern China, in 1989, the authors studied the relation between body mass and blood pressure in three community-based random samples: rural Yi farmers (5,023 men, 3,218 women); Yi migrants (1,656 men, 919 women); and Han Chinese living in an urban setting (2,173 men, 1,516 women). The Yi farmers had virtually no obesity or hypertension and had little rise in blood pressure with age. The Yi migrants and Han had a steeper slope of blood pressure with age and consequently more hypertension. For men and women, respectively, mean body mass index (weight (kg)/height (m)2) was 20.6 and 21.0 in the Yi farmers, 21.3 and 21.4 in the Yi migrants, and 21.0 and 21.4 in the Han. Both systolic and diastolic blood pressure were positively related to body mass index in all six ethnicity-sex groups, and the association remained statistically significant after adjustment for age, heart rate, smoking, alcohol intake, and physical activity. The change in mean blood pressure for each kg/m2 increase in body mass index, after adjustment for community of residence, was 1.47 mmHg for systolic pressure and 1.13 mmHg for diastolic pressure. The association between body mass index and blood pressure was greater in men than in women and greater in Yi migrants and Han than in Yi farmers. The percentages of hypertension attributable to overweight (body mass index > or = 25) among the Yi farmers, Yi migrants, and Han, respectively, were 4.1%, 34.1%, and 24.0% for men and 0%, 26.2%, and 28.9% for women. Thus, even in this lean Chinese population with a low mean blood pressure, body mass was positively and independently associated with increased blood pressure.

Molecular basis of antigenic variation in infectious bursal disease virus

Four antigenically different strains of infectious bursal disease virus (IBDV), characterized by their reactivities with a panel of neutralizing monoclonal antibodies (MAbs), were selected to determine the molecular basis of antigenic variation. The large genome segment A, encoding the structural proteins of the U.S. variants GLS, DS326, E/Del and the vaccine strain D78, was cloned and sequenced. Comparison of the deduced amino acid sequences of the U.S. variants with other IBDV strains showed that most of the amino acid substitutions occur in the central region between residues 212 to 332, especially in the two hydrophilic regions between residues 212 to 223 and residues 314 to 324 of VP2 protein. By comparing the amino acid sequences of these variant viruses and their reactivities with IBDV specific MAbs, the putative amino acids involved in the formation of virus-neutralizing epitopes were identified. Comparison of the D78 versus PBG98 sequence showed that Gln at position 249 (Gln249) appears to be critical in binding with MAb B69. Similarly, comparison of the U.S. variant sequences with other serotype 1 sequences showed unique substitution(s) at residue Glu321 in GLS, residues Ile286, Asp318, Glu323 in E/Del, and residues Glu311 and Gln320 in DS326, which could be potential residue(s) involved in the recognition of MAb57, MAb67, and MAb179 epitopes, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Iron-induced conformational change in human lactoferrin: demonstration by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and analysis of effects of iron binding to the N and C lobes of the molecule

Analysis of Fe-saturated- and apo-lactoferrin by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) without heating the samples prior to application revealed a substantial difference in mobility. The mobility shift was fully reversible on repetitive removal and readdition of Fe. Binding of a single Fe to the N-lobe binding site was sufficient to cause the gel shift; binding of a second Fe to the C-lobe site did not further alter mobility. Removal of Fe from the N lobe of Fe2 lactoferrin did not restore mobility to the position of apolactoferrin. No change in mobility with Fe binding was detected in N and C lobes isolated from intact lactoferrin by controlled trypsin digestion. The data indicate that a conformational change induced by Fe binding to a single site on lactoferrin is detectable by SDS-PAGE and that this change requires an intact molecule, possibly due to the need for interactions between the two homologous lobes of the molecule.

In vitro transcription and binding analysis of promoter regulation by a host-specific signal in a phytopathogenic fungus

The PDA1 promoter of the phytopathogenNectria haematococca MPVI (anamorph Fusarium solani) offers a model for regulation of a fungal virulence gene in response to plant host-specific signals. Expression of the PDA1 gene, encoding pisatin demethylase, is induced in culture by pisatin, the isoflavanoid phytoalexin of pea. This pisatin induction is suppressed by nutritional factors. We have been studying the mechanism of pisatin induction through in vitro identification of regulatory factors and regulatory elements of the PDA1 promoter. We have developed an in vitro transcription system for N. haematococca which accurately initiates at the PDA1 promoter and reflects the pisatin induction of PDA1 mRNA observed in vivo. This in vitro activity allowed a functional test of a limited set of 5' upstream deletions in the PDA1 promoter. In vitro binding studies have identified a DNA binding factor which is appears in mycelial extract after treatment of the mycelium with pisatin. This pisatin-responsive factor binds to a minimum size region of 35 bp approximately 500 bp upstream of the transcription initiation site. Tests using the in vitro transcription assay and in vivo competition both indicate a role for this binding region in the high expression of PDA1 under pisatin-induced conditions. Southwestern blotting has identified one component of this binding activity to be a approximately 35 kDa protein. The availability of these functional and structural tests of function, in conjunction with complementary in vivo tests, allow the detailed dissection of the signal pathway leading from exposure of the cell to pisatin towards the activation of PDA1 transcription.

Changes in carotid blood flow and electrocardiogram in humans during and after walking on a treadmill

Blood flow velocity in the common carotid artery and the electrocardiogram were measured simultaneously by telemetry in seven male subjects during 20-min walking on a treadmill at an exercise intensity corresponding to a mean oxygen uptake of 26.0 (SD 2.9) ml.kg-1.min-1. The mean cardiac cycle was shortened from 0.814 (SD 0.103) s to 0.452 (SD 0.054) s during this exercise. Of this shortening, 73% was due to shortening of the diastolic period and 27% to shortening of the systolic period. In the relatively small shortening of the mean systolic period [from 0.377 (SD 0.043) s to 0.268 (SD 0.029) s], the isovolumetric contraction time was shortened by 56%. During exercise, the heart rate (fc) increased by 79.4% [from 74.3 (SD 9.3) beats.min-1 to 133.3 (SD 14.8) beats.min-1], and the peak blood velocity (S1) in the common carotid artery increased by 56.1% [from 0.82 (SD 0.10) m.s-1 to 1.28 (SD 0.11) m.s-1]. After exercise, the S1 decreased rapidly to the resting level. The fc decreased more slowly, still being higher than the initial resting level 5 min after exercise. The diastolic velocity wave and the end-diastolic foot decreased during exercise. The blood flow rate in the carotid artery increased transiently by 13.5% at the beginning of exercise [from 5.62 (SD 0.63) ml.s-1 to 6.38 (SD 0.85) ml.s-1] and by 26.5% at the end of the exercise period [from 5.62 (SD 0.63) ml.s-1 to 7.11 (SD 1.34) ml.s-1].(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of SC1001-sodium on ADA activity of the thymus, spleen and brain in repeated seizure rats]

Twenty nine adult SD rats in the experiment were randomly separated into two groups. Nineteen rats of them were intramuscularly injected (i.m.) with Coriaria lactone (CL, 2.5 mg/kg for female rat; 30 mg/kg for male rat) two days a time, continued 28 times, to induce repeated seizures, as the experimental group. The control group (n = 10) was injected with normal saline (N.S.) in the same volume as that of CL. The rats of experimental group were subdivided into a treatment group (n = 9) with SC1001Na (200 mg/kg) and a placebo group (n = 10) receiving N.S. in the same volume as that of SC1001 Na. All rats of repeated seizure were administered once every day for a week. The results indicated that SC1001Na (200 mg/kg) could inhibit in some degree the growth of immune organs (spleen and thymus) and significantly decrease the ADA activity of thymus, cerebrum and cerebellum, suggesting that the antiepileptic mechanism of SC1001Na is probably related with the decreased activity of ADA and the increased adenosine level in brain.

Alcohol use and blood pressure in an unacculturated society

Alcohol intake has been associated with higher blood pressure in acculturated populations but not in unacculturated societies. We performed a cross-sectional survey of a random community sample of 5023 male Yi rural farmers and 1656 Yi and 2173 Han men living in an urban setting. Average alcohol intake among drinkers was 36.4 g/d in Yi farmers, 56.5 g/d in Yi migrants, and 38.7 g/d in Han men. Age-adjusted mean diastolic blood pressure was 66.9, 70.5, and 71.7 mm Hg, respectively. Diastolic blood pressure was higher at higher alcohol intakes in all three groups (all P < .001). After adjustment for age, body mass index, heart rate, smoking, and physical activity, the change (95% confidence interval) in diastolic blood pressure for each standard drink was 0.50 (0.38-0.62), 0.31 (0.18-0.43), and 0.24 (0.07-0.40) mm Hg for Yi farmers, Yi migrants, and Han men, respectively. The percentage of variance in diastolic blood pressure explained by alcohol intake was 5% for Yi farmers, 4% for Yi migrants, and 2% for Han men. In a random sample of 831 men, these associations were independent of urinary sodium, potassium, calcium, and magnesium and sodium-potassium ratio. In the Yi farmers, associations were less strong for systolic blood pressure and no longer significant after adjustment. Approximately 33% of hypertension could be attributed to daily alcohol use in the Yi groups compared with 9.5% in the Han people.(ABSTRACT TRUNCATED AT 250 WORDS)

[Preconcentration of trace Fe, Mn, Cu and Cd in water with charcoal and determination by flame atomic absorption spectroscopy]

The absorption of Fe, Mn, Cu and Cd by charcoal and the influence of pH, particle size and temperature on absorption were studied. A method for the preconcentration of these irons in water was established, and with flame atomic absorption spectroscopy a content as low as microgram/L could be determined. The recovery and the coefficient of variance (n = 6) were in the range of 90-113% and 2.6-9.9%, respectively. The proposed method is simple, rapid, accurate reproducible and suitable for the preconcentration and determination of titled metal irons in different kinds of water.

Localization of chromosome 9p homozygous deletions in glioma cell lines with markers constituting a continuous linkage group

Southern blot analyses of the 9p-localized type I interferon (IFN) genes in DNAs obtained from malignant glioma cell lines and glial tumor tissue have indicated that homozygous deletions of the IFN-alpha and IFN-beta genes often occur during the development of the highly malignant central nervous system neoplasm, glioblastoma. We have applied a set of markers that span the IFN region on 9p to the analysis of DNAs from 30 human glioma cell lines in order to define the region of homozygous deletion associated with this cancer more precisely. Fourteen of the cell lines revealed either complete (12 cases) or partial (2 cases) homozygous deletions of the IFN-alpha gene cluster; no instances of homozygous deletions were observed that did not involve the IFN-alpha region. Genomic DNA identified by the markers nearest to and flanking the IFN-alpha genes were retained in 5 of the cases with homozygous deletions. Consequently, these results limit the extent of homozygous deletions in glioma cell lines to a small region of 9p21-p22 that includes most of the type I IFN locus.

Autoimmune disease in mice due to integration of an endogenous retrovirus in an apoptosis gene

The MRL-lpr/lpr mouse strain is a model of systemic autoimmune disease. In this model, intrinsic defects of intrathymic T cell development include defective deletion of self-reactive T cells and expression of endogenous retroviruses. Defective deletion of self-reactive T cells in the thymus has been proposed to be due to germline mutation in the Fas apoptosis gene. Using different fragments of a Fas cDNA probe, we determined that the lpr/lpr mutation is a 5.3-kb insertion of DNA within the second intron of the Fas gene. cDNA corresponding to this region was then derived from thymic RNA from MRL-lpr/lpr and MRL- +/+ mice using the polymerase chain reaction. All thymic RNA samples from MRL-lpr/lpr mice yielded a unique product that was 168 bp larger than that of MRL- +/+ mice. Complete sequence analysis indicated that this inserted sequence had 98% homology with a sequence from the 3' long terminal repeat of the early transposon (ETn). RNA analysis indicated higher expression of ETn RNA in the thymus of MRL-lpr/lpr than MRL- +/+ mice. The interdependence of ETn expression and abnormal Fas expression was then analyzed in a CD2-Fas transgenic mouse model in which a full-length murine Fas cDNA under the regulation of the CD2 promoter and enhancer was used to correct defective Fas expression in T cells of MRL-lpr/lpr mice. In these mice, reduced thymic ETn expression was observed, confirming that high ETn expression is related to abnormal Fas expression. These results establish a link between endogenous retrovirus expression, abnormal Fas expression, and autoimmune disease.

Expression and diagnostic utility of hepatitis E virus putative structural proteins expressed in insect cells

The full-length putative structural proteins encoded by open reading frame 2 (ORF2) and ORF3 of hepatitis E virus have been cloned and expressed in recombinant baculovirus. Sera obtained from 28 Sudanese pediatric patients with acute hepatitis and 19 pediatric control patients were analyzed for reactivity to hepatitis E virus by using the baculovirus-expressed ORF2 and ORF3 proteins in a Western blot (immunoblot) format. Seventeen of the 18 patients classified as having non-A, non-B hepatitis, without acute antibody markers for hepatitis A, B, or C viruses, Epstein-Barr virus, or cytomegalovirus, were shown to have immunoglobulin M (IgM) antibodies to the recombinant ORF2 protein, as did two patients with chronic hepatitis B, three of seven patients with acute hepatitis A, and one patient with acute hepatitis B. None of the 19 control patients had IgM antibodies against the ORF2 or ORF3 proteins. The Western blot assay using the baculovirus-expressed ORF3 protein did not appear to be as sensitive as the assay based on the ORF2 protein. Only 10 of the patients classified as having non-A, non-B hepatitis had IgM antibodies to the baculovirus-expressed ORF3 protein. We conclude that a Western blot assay which uses a baculovirus-expressed ORF2 protein is both sensitive and specific for diagnosing acute hepatitis E.

Validity of physicians' self-reports of cardiovascular disease risk factors

To determine the accuracy of self-reported risk factors in 78 physicians, self-reported information was compared to findings on a standardized examination. Measured weight (r = 0.98), height (r = 0.95), body mass index (r = 0.96), systolic blood pressure (SBP) (r = 0.72), and diastolic blood pressure (DBP) (r = 0.60) were highly correlated with self-reported values (all P < 0.0001). Mean self-reported SBP and DBP did not differ from measured values; measured weight was 1.5 kg greater and measured height 1.4 cm less than self-reported values (both p < 0.0001). Regression of measured on self-reported values indicated excellent agreement except for DBP and heart rate. Differences between measured and self-reported values were not associated with a variety of variables except for a greater difference in SBP at higher levels of SBP. None of the 60 self-reported nonsmokers had expired carbon monoxide levels greater than 10 ppm. These results indicate that physicians' self-reports of height, body mass index, SBP, and smoking are extremely accurate and suitable for research purposes.

[The multi-channel VEPs topography in optic neuritis]

The multi-channel VEPs topographies of 20 normal persons and 22 patients suffered from optic neuritis were recorded. In normal subjects, the topography showed symmetric distribution by full-field stimulation and paradoxical lateralization by half-field stimulation. In patients with optic neuritis, it showed asymmetric distribution most on the temperal side, some on the nasal side and occasionally in the middle by full-field stimulation. The result suggests that the optic nerve may be damaged on either temperal or nasal. The effect of the early diagnosis and evaluating treatment using topography is also discussed.

Agreement between overnight and 24-hour urinary cation excretions in southern Chinese men

Agreement between overnight and 24-hour urinary sodium, potassium, calcium, and magnesium excretion was studied in a sample of 63 normotensive Southwestern Chinese men: 30 Yi farmers and 33 urban residents in April 1989. Overnight (8-hour) and 24-hour urine specimens were collected on 3 consecutive days. Estimated correlation coefficients between 24-hour and overnight mean true values were 0.863 and 0.906 for sodium, 0.736 and 0.816 for potassium, 0.902 and 0.725 for calcium, and 0.733 and 0.703 for magnesium in Yi farmers and urban residents, respectively. Hourly overnight urinary sodium and potassium excretion rates were significantly lower than the corresponding hourly 24-hour urinary excretion rates: -0.60 and -1.99 mmol/hour for sodium, -1.24 and -0.48 mmol/hour for potassium (all p < 0.05) in Yi farmers and urban residents, respectively. In multiple regression analyses, the differences between 24-hour and overnight urinary sodium and potassium excretion rates were significantly and positively related to differences between 24-hour and overnight creatinine excretion rates. The ratios of intraindividual to interindividual variance were lower for 24-hour collections than for overnight collections for sodium and calcium, but the differences in these ratios for potassium and magnesium were small. For sodium and calcium, twice as many overnight as 24-hour collections were required to estimate the correlation between cations and blood pressure with the same accuracy; for potassium and magnesium, overnight and 24-hour collections were equally accurate. These results indicate that in normotensive populations such as the one studied, overnight urine collections may be used to estimate 24-hour cation excretion. The underestimate of cation excretion by assessments based on collection of overnight specimens may be due to either a lower creatinine clearance or a lower intake of cations at night.

Infectious bursal disease virus structural proteins expressed in a baculovirus recombinant confer protection in chickens

Plasmids were prepared that contained cDNA segments of the large genomic segment A of infectious bursal disease virus (IBDV) strain GLS-5. The genes encoding the IBDV structural proteins (VP2, VP3 and VP4) were introduced into the baculovirus transfer vector pBlueBacI to obtain a recombinant baculovirus vIBD-7. When insect cells were infected with recombinant viruses, the result was synthesis of IBDV precursor proteins which were processed by the viral protease. The recombinant IBDV antigens were characterized by immunoprecipitation with monoclonal antibodies (MAbs) and polyclonal antiserum to IBDV, and by antigen-capture ELISA using a panel of IBDV-specific MAbs. The recombinant IBDV antigens closely resembled the native IBDV proteins and reacted with all the GLS-5 strain-specific neutralizing MAbs that recognize only conformational epitopes of IBDV. When susceptible chickens were inoculated with the recombinant IBDV antigens, virus-neutralizing antibodies were induced that conferred up to 79% protection against IBDV challenge.

[Gas chromatographic analysis of nicotine in indoor air]

An analytical method for the determination of nicotine in indoor air was developed. Air sample was collected in absorption solution of 1% NaHSO4. After alkalization and heptance extraction, the content of nicotine in the sample was determined by gas chromatography with FID. The average sampling efficiency was 93.6%. The recovery rate was 89.3%-105.5% (mean = 98.4%). The coefficient of variation was 1.7-4.1%. Under the sampling condition the detection limit was 0.01 microgram/m3. After discussing the stability and extraction efficiency of the sample, we found the air sample collected in the absorption solution was stable for at least 7 days in refrigerator. The field experimental results show that the method is simple, reliable and suitable for collecting and determining trace nicotine in indoor air.

Liquid holding effects on methylmercury genotoxicity in human lymphocytes

Methylmercury chloride (MMC) treatment of resting (G0) human lymphocytes resulted in the formation of chromosome and chromatid aberrations. This treatment also induced aneuploidy in second metaphases, suggesting that MMC produces stable damage involved in chromosome segregation errors. The storage of treated cells (liquid holding for 48 h before cell proliferation) did not result in an important recovery from induced cell toxicity or chromosome damage. Therefore, MMC seems to be an X-ray-like agent, able to produce long-lasting damages giving rise to both structural and numerical chromosome abnormalities.

A study on the clinical effect and immunological mechanism in the treatment of Hashimoto's thyroiditis by moxibustion

71 cases of Hashimoto's thyroiditis were treated by moxibustion and their immune function and thyroid function were observed. It was found that moxibustion was able to reduce the thyroid antibodies in the peripheral blood of the patients with hypothyroidism and to recover their thyroid function. It was also found that moxibustion could lower the thyroid antibody secretory levels and ADCC (antibody-dependent cell-mediated cytotoxicity) activities of the lymphocytes. In addition, the action of moxibustion in reducing the secretion of thyroid antibodies was related to its action of regulating the proportions of T lymphocyte subsets. The results indicate that the treatment of Hashimoto's thyroiditis by moxibustion is probably accomplished through its effect in regulating the relationship among the T lymphocyte subsets.

Direct injection analysis of atenolol enantiomers in plasma using an achiral/chiral coupled column HPLC system

A novel HPLC system was developed with an achiral/chiral coupled column for the direct injection analysis of atenolol (AT) enantiomers in plasma. The system consists of a size-exclusion column, an ODS silica column and a newly developed beta-cyclodextrin perphenylcarbamate(ph-beta-CD)-bonded silica column connected in a series via two switching valves. The neat plasma sample was directly injected onto the size-exclusion column, and the deproteinized fraction of AT enantiomers was concentrated on the ODS silica column. The enantiomers were then transferred and separated mutually on the ph-beta-CD silica column. The calibration line for each of the AT enantiomers was linear in the range of plasma concentration of 10-200 ng/ml (r > 0.9997) with good reproducibility (CV < 9.7%, n = 20). The recoveries from plasma were almost complete (> 97.4%) for both enantiomers. One analysis finished within 30 min. The developed system was applied to the enantioselective determination of plasma concentration-time curve of AT after the oral administration of racemic AT to a healthy volunteer.

Direct and indirect effects of valinomycin upon cytochrome c oxidase

Valinomycin binds beef heart cytochrome c oxidase with approximately equimolar stoichiometry (one valinomycin per cytochrome aa3 complex) and a Kd of 2.0-3.0 microM, almost independent of ionic strength, but dependent upon the presence of K+ ions. Its effects are twofold: a red shift in the Soret maximum of the resting enzyme from 419 to 422 nm, with an appreciable delta EmM at 430-410 nm, and an inhibition of catalytic activity of about 50%. Much smaller concentrations of valinomycin are sufficient to induce the release of respiration in cytochrome oxidase vesicles by nigericin. Intermediate levels of valinomycin alone are capable of partially releasing respiratory control, probably by increasing H+ permeability as well as that of K+. The amounts of valinomycin required to bind the enzyme are much greater than those required to collapse delta psi in vesicular systems in a steady state or during proton pulse experiments. We conclude that the two effects--a direct one upon the enzyme and an indirect one via abolition of electrogenic potentials--are of separate origins. The existence of the direct effect does not call for reinterpretation of classical results showing proton translocation, which are adequately explained by the indirect action of valinomycin as an ionophore.

Serum cholesterol in young men and subsequent cardiovascular disease

BACKGROUND

The increased risk of cardiovascular disease associated with higher serum cholesterol levels in middle-aged persons has been clearly established, but there have been few opportunities to examine a potential link between serum cholesterol levels measured in young men and clinically evident premature cardiovascular disease later in life.

METHODS

We performed a prospective study of 1017 young men (mean age, 22 years) followed for 27 to 42 years to quantify the risk of cardiovascular disease and total mortality associated with serum cholesterol levels during early adult life. The mean serum cholesterol level at entry was 192 mg per deciliter (5.0 mmol per liter).

RESULTS

During a median follow-up of 30.5 years, there were 125 cardiovascular-disease events, 97 of which were due to coronary heart disease. The serum cholesterol level at base line was strongly associated with the incidence of events related to coronary heart disease and cardiovascular disease, as well as to total mortality and mortality due to cardiovascular disease. The risks were similar whether the events occurred before or after the age of 50. In a proportional-hazards analysis adjusted for age, body-mass index (the weight in kilograms divided by the square of the height in meters), the level of physical activity, coffee intake, change in smoking status, and the incidence of diabetes and hypertension during follow-up, a difference in the serum cholesterol level at base line of 36 mg per deciliter (0.9 mmol per liter)--the difference between the 25th and 75th percentiles of cholesterol level in the study population at base line--was associated with an increased risk of cardiovascular disease (relative risk, 1.72; 95 percent confidence interval, 1.39 to 2.14), coronary heart disease (relative risk, 2.01; 95 percent confidence interval, 1.59 to 2.53), and mortality due to cardiovascular disease (relative risk, 2.02; 95 percent confidence interval, 1.23 to 3.32). A difference in the base-line serum cholesterol level of 36 mg per deciliter was significantly associated with an increased risk of death before the age of 50 (relative risk, 1.64; 95 percent confidence interval, 1.03 to 2.61), but not with the overall risk of death (relative risk, 1.21; 95 percent confidence interval, 0.93 to 1.58).

CONCLUSIONS

These findings indicate a strong association between the serum cholesterol level measured early in adult life in men and cardiovascular disease in midlife.

Mapping of sensory responses to epidural stimulation of the intraspinal neural structures in man

A database is presented of sensory responses to electrical stimulation of the dorsal neural structures at various spine levels in 106 subjects subjected to epidural spinal cord stimulation. All patients were implanted for chronic pain management and were able to perceive stimulation in the area of pain. All patients entered in this study were able to reliably report their stimulation pattern. Several patients were implanted with more than one electrode array. The electrode arrays were placed in the dorsal epidural space at levels between C-1 and L-1. The structures that were likely involved include the dorsal roots, dorsal root entry zone, dorsal horn, and dorsal columns. At the present time, exact characterization of the structure being stimulated is possible only in limited instances. Various body areas are presented with the correspondent spine levels where implanted electrodes generate paresthesias. Areas that are relatively easy targets for stimulation are the median aspect of the hand, the abdominal wall, the anterior aspect of the thigh, and the foot. Some areas are particularly difficult to cover with stimulation-induced paresthesias; these include the C-2 distribution, the neck, the low back, and the perineum.

Mapping of sensory responses to epidural stimulation of the intraspinal neural structures in man

A database is presented of sensory responses to electrical stimulation of the dorsal neural structures at various spine levels in 106 subjects subjected to epidural spinal cord stimulation. All patients were implanted for chronic pain management and were able to perceive stimulation in the area of pain. All patients entered in this study were able to reliably report their stimulation pattern. Several patients were implanted with more than one electrode array. The electrode arrays were placed in the dorsal epidural space at levels between C-1 and L-1. The structures that were likely involved include the dorsal roots, dorsal root entry zone, dorsal horn, and dorsal columns. At the present time, exact characterization of the structure being stimulated is possible only in limited instances. Various body areas are presented with the correspondent spine levels where implanted electrodes generate paresthesias. Areas that are relatively easy targets for stimulation are the median aspect of the hand, the abdominal wall, the anterior aspect of the thigh, and the foot. Some areas are particularly difficult to cover with stimulation-induced paresthesias; these include the C-2 distribution, the neck, the low back, and the perineum.

Changes in cardiac rhythm in man during underwater submersion and swimming studied by ECG telemetry

A previously reported method for electrocardiographic (ECG) telemetry in water using frequency-modulated current was improved to obtain more stable ECGs. The ECGs of seven healthy men were monitored using the improved method during and after whole-body submersion or underwater swimming. Bradycardia and arrhythmias were observed during the submersion, and transient tachycardia was detected after the start of underwater swimming, followed by bradycardia with arrhythmias. Three different types of arrhythmias were observed: sinus arrhythmia (SA), supraventricular extrasystole (SE) and ventricular extrasystole (VE). SA and SE tended to develop during the latter half of the period of submersion or underwater swimming, and especially after the restart of breathing. VEs were detected in only one subject during submersion, whereas they occurred in most subjects during and after underwater swimming. Individual variations were found in development of arrhythmias, one subject showing no arrhythmia. Bradycardia, SA and SE could depend on vagal suppression in underwater conditions, and VE may be related to the effect of muscular movement on cardiac function in addition to vagal inhibition.

Analysis of parameters for epidural spinal cord stimulation. 3. Topographical distribution of paresthesiae--a preliminary analysis of 266 combinations with contacts implanted in the midcervical and midthoracic vertebral levels

As a part of the systematic analysis of parameters involved in electrical epidural spinal cord stimulation therapy, distribution of paresthesiae in accordance with the position of contacts, as related to midline and vertebral level of contacts, was investigated. A preliminary analysis performed for 266 combinations having contacts implanted in the midcervical and low-thoracic vertebral levels showed that the topographical spread of the paresthesiae did not always cover the classical dermatomes. Significant paresthesiae spread was found as follows: C4-midline, unipolar combinations; the hand, forearm and upperarm, bipolar combinations; the hand, forearm; C4-lateral, unipolar combinations: the anterior shoulder, forearm, upper arm and hand, bipolar combinations: the hand, forearm and upper arm; T10-midline, unipolar combinations: the anterior and posterior of thigh, leg, knee, ankle and foot, bipolar combinations: the anterior and posterior thigh, leg, knee and foot; T10-lateral, unipolar combinations: the abdomen, anterior leg, knee and anterior thigh, bipolar combinations: the anterior thigh, anterior leg, knee and foot. This preliminary analysis suggests that more detailed studies would be worthwhile in the investigation of sensory responses to electrical stimulation of the spinal cord with epidural electrodes. Findings from such investigations could also be useful to extend our present anatomical knowledge of central and peripheral sensory neural structures.

Effect of captopril on fluctuations of blood pressure and renal blood flow in rats

Arterial blood pressure and renal blood flow (RBF) fluctuations in rats were studied by autoregressive (AR) and autoregressive-moving average (ARMA) modeling. These estimation procedures provided greater sensitivity and frequency resolution than classic fast Fourier transform (FFT)-based methods and also require shorter observation periods. We estimated the transfer function of RBF autoregulation to test whether inhibition of angiotensin-converting enzyme impairs whole kidney dynamic autoregulation. The transfer function in control animals measured with the ARMA method was similar to transfer functions obtained previously, using FFT methods. Because of better frequency resolution, we also detected an oscillation in RBF at 50 mHz, the same frequency as an oscillation in tubular pressure and glomerular filtration rate that had been attributed to tubuloglomerular feedback (TGF), but that FFT methods had not previously found in whole kidney blood flow. Captopril increased the amplitude of RBF fluctuations and increased the gain of the transfer function at frequencies below 100 mHz, a frequency bandwidth previously associated with TGF. The increased gain indicates that TGF operates less effectively to mediate dynamic autoregulation when angiotensin conversion is inhibited. Gain at frequencies greater than 100 mHz, previously ascribed to the myogenic mechanism, was not affected by captopril. These results show that angiotensin, by modulating TGF, reduces fluctuations of RBF about the mean value.

The long-term observation of the transplantation of encapsulated rat islets to the diabetic mice

Rat islets encapsulated in the immuno-isolated membrane were transplanted intraperitoneally into 11 streptozotocin induced diabetic mice. The effective rate was 91% while all rejected in the 11 nonencapsulated xenograft group. 4 mice showed complete remission and longest normoglycemic period in those mice was 360 days. The pathological changes of islets of the long-term successful xenograft group were studied and showed atrophy. It proved that the immuno-isolated membrane can protect rejection during xeno-transplantation.

Dibucaine interacts differently with membrane and protein in cytochrome c oxidase systems

Dibucaine acts as a weak protonophore in cytochrome c oxidase proteoliposomes. At low concentrations in the presence of permeant anions, it stimulates turnover and collapses enzyme-generated pH gradients. At higher concentrations, dibucaine inhibits activity of cytochrome c oxidase in proteoliposomes and the isolated enzyme. It also induces a red shift in the resting spectrum, indicating a change at the binuclear centre. This spectroscopic effect is kinetically biphasic. Dibucaine inhibits steady-state oxidase activity, but not the rate of the red shift in the cytochrome a3 Soret band during turnover. It reacts faster with the partially reduced state than with resting enzyme. The inhibition is kinetically biphasic with a noncompetitive Ki approximately 0.5 mM. Excess dibucaine effects a maximal turnover decline of 80%. At low ionic strength only the total Vmax is affected; tight binding of cytochrome c and turnover at the "tight" site are unaffected. Dibucaine may bind to an anionic site in a hydrophobic pocket, modifying electron transfer from cytochrome a and CuA to cytochrome a3 - CuB and the oxidized spectrum of the latter centre. Stimulation of turnover in cytochrome c oxidase in proteoliposomes is due to a separate membrane-dependent proton translocation catalysed by dibucaine in the presence of permeant anions.

Valinomycin modifies phosphorescence quenching in cytochrome c oxidase

The spectrum of resting cytochrome c oxidase is modulated by valinomycin addition, which induces a red shift of the Soret band. The enzyme is known both to fluoresce and phosphorescence, effects which can be modulated by certain protein reagents and quenchers. Valinomycin had little effect upon fluorescence at 335 nm, whether excited at 295 nm or 280 nm (tryptophans or both tryptophans and tyrosines, respectively). Phosphorescence at 445 nm was slightly enhanced upon the binding of valinomycin to the enzyme, suggesting a small conformational change accompanying the spectral shift of the heme groups. The quenching by nitrite of the phosphorescence excited at 260 nm, but not that excited at 295 nm, was diminished by valinomycin. This suggests that the valinomycin-induced conformational change may involve (i) a change in the accessibility of tyrosines to the quencher and/or (ii) a change in distribution of distances and/or orientations between populations of tyrosines and tryptophans.

A CD44-like endothelial cell transmembrane glycoprotein (GP116) interacts with extracellular matrix and ankyrin

We used complementary biochemical and immunological techniques to establish that an endothelial cell transmembrane glycoprotein, GP116, is a CD44-like molecule and binds directly both to extracellular matrix components (e.g., hyaluronic acid) and to ankyrin. The specific characteristics of GP116 are as follows: (i) GP116 can be surface labeled with Na 125I and contains a wheat germ agglutinin-binding site(s), indicating that it has an extracellular domain; (ii) GP116 displays immunological cross-reactivity with a panel of CD44 antibodies, shares some peptide similarity with CD44, and has a similar 52-kDa precursor molecule, indicating that it is a CD44-like molecule; (iii) GP116 displays specific hyaluronic acid-binding properties, indicating that it is a hyaluronic acid receptor; (iv) GP116 can be phosphorylated by endogenous protein kinase C activated by 12-O-tetradecanoylphorbol-13-acetate and by exogenously added protein kinase C; and (v) GP116 and a 20-kDa tryptic polypeptide fragment of GP116 from the intracellular domain are capable of binding the membrane-cytoskeleton linker molecule, ankyrin. Furthermore, phosphorylation of GP116 by protein kinase C significantly enhances GP116 binding to ankyrin. Together, these findings strongly suggest that phosphorylation of the transmembrane glycoprotein GP116 (a CD44-like molecule) by protein kinase C is required for effective GP116-ankyrin interaction during endothelial cell adhesion events.

[Effects of mixture of Astragalus membranaceus, Fructus Ligustri lucidi and Eclipta prostrata on immune function in mice]

A Chinese medicine mixture containing Astragalus membranaceus, Fructus Ligustri Lucidi and Eclipta prostrata(AFE), was fed to mice 9g/kg, 20g/kg, respectively for seven days. Observe the effects of AFE on the immune function in mice. The experiment showed that the two dosages of AFE could obviously raise the conversion percentage of lymphocytes (P < 0.01) and serum IgG level (41%-47%) of the mice. The weights of the thymus and spleensed increased in the two groups compared with those in the normal control. The larger dosage of AFE could also raise activity of Adenosine Deaminase (ADA) obviously (P < 0.01). AFE turned out a resistance to the immunosuppressive effect caused by cyclophosphamide.

Biopathologic characteristics of DNA content in crypt cells of transitional mucosa adjacent to carcinomas of the rectum and rectosigmoid

The transitional mucosa (TM) adjacent to carcinomas of the large bowel shows histologic and mucin histochemical changes that may indicate premalignant change and may be of prognostic value after radical resection. In this study, 10 anterior resection specimens from patients with carcinomas of the rectum and rectosigmoid were used to compare the nuclear DNA content in TM with those in cancer tissue and with those in nontransitional mucosa (N-TM; i.e., uninvolved mucosa remote from tumors showing normal histologic and mucin histochemical features). The nuclear DNA content was assessed using DNA image cytometry on Feulgen-stained sections. As compared with N-TM, crypts in TM contained greater numbers of cells, were elongated, and were more likely to be branched with marked sialomucin secretion, accompanied by a marked reduction in the normal sulfomucin content. The mean nuclear DNA content in the upper, middle, and lower thirds of crypts was significantly higher in TM than in N-TM, and the nuclear DNA content in TM exhibited no correlation to that in tumors. The results suggest that TM adjacent to carcinomas of the rectum and rectosigmoid has higher proliferative activity, providing further evidence that TM may be an unstable premalignant change.