Micellar electrokinetic capillary chromatographic analysis of platelet activating factor in human blood by indirect ultraviolet detection

In this paper, 1-O-hexadecyl and 1-O-octadecyl-2-acetyl-sn-glycero-3- phosphorylcholine (C16-AGEPC and C18-AGEPC) in the platelet activating factor of human blood were analyzed by micellar electrokinetic capillary chromatography (MECC) with indirect ultraviolet absorption detection at 254 nm. The optimum running buffer for the separation contained 50 mmol/l sodium dodecy sulphate, 20 mmol/l potassium hydrogen phthalate, 10 mmol/l borax and 3 mol/l urea (pH 6.8). The separation was completed within 10 min. The detection limits of C16-AGEPC and C18-AGEPC were the same, i.e. 60 ng/ml (k = 3). The analytical precision (n = 6) was 2.8-3.0% and 1.4-1.7% for the determination (peak height mode) and for the measurement of the migration times, respectively. The application of this method to the clinical samples was demonstrated.

Stroke in the People's Republic of China. II. Meta-analysis of hypertension and risk of stroke

BACKGROUND AND PURPOSE

In the People's Republic of China (PRC), stroke accounts for over 1 million deaths per year, more than three times the number of deaths from ischemic heart disease. To quantify the effect of hypertension on stroke in the PRC, we conducted a meta-analysis and estimated the population attributable risk of stroke due to hypertension.

METHODS

We searched the Chinese Medical Literature Index and MEDLINE databases to identify studies on the relationship between hypertension and stroke conducted in the PRC. The overall relative risk of stroke in hypertensive persons and the population attributable risk of stroke due to hypertension were calculated by pooling the risk estimates from individual studies.

RESULTS

A total of 12 epidemiological studies with 2379 stroke cases was identified. The overall relative risk of stroke associated with hypertension was 5.43 (95% confidence interval [CI], 4.62 to 6.39). The relative risk was similar for hemorrhagic (5.44; 95% CI, 3.99 to 7.40) and ischemic (5.25; 95% CI, 3.95 to 6.98) stroke. On the basis of data from the 1990 PRC population census, vital statistics, and the 1991 PRC National Hypertension Survey, the excess annual mortality from stroke due to hypertension was estimated to be at least 545,000 deaths, with a population attributable risk of 49.5%.

CONCLUSIONS

Our data suggest that hypertension is an important risk factor for stroke in the PRC and that hypertension may account for about half of all deaths from stroke in that country. Treatment and prevention of hypertension should be an important societal goal in the PRC.

Stroke in the People's Republic of China. I. Geographic variations in incidence and risk factors

BACKGROUND AND PURPOSE

Stroke is a major cause of death in the People's Republic of China (PRC), and the geographic distribution of stroke death varies substantially. We conducted an ecological analysis to investigate the relationship of prevalence of hypertension and other risk factors with stroke incidence and mortality in the PRC.

METHODS

The relationship between prevalence of risk factors and stroke incidence and mortality in the PRC was assessed in 29 provinces by examining risk factor data from PRC national surveys and incidence and mortality from the 1986 PRC National Stroke Study.

RESULTS

A highly statistically significant correlation between prevalence of hypertension and stroke incidence (r = .838, P < .001) and mortality (r = .841, P < .001) was observed. Prevalence of hypertension explained over 70% of the geographic variability in stroke incidence (partial R2 = .703) and mortality (partial R2 = .707) in the PRC. There was a north-south gradient, with a higher prevalence of hypertension and stroke incidence and mortality in the north compared with the south of the country. In multiple Poisson regression analysis, a 10% increase in the prevalence of hypertension was associated with a 2.80-fold higher incidence and 2.68-fold higher mortality from stroke, whereas a 10% increase in the prevalence of alcohol consumption was associated with a 29% higher incidence and a 16% higher mortality from stroke. A 10% increase in the prevalence of cigarette smoking was associated with a 19% higher mortality from stroke.

CONCLUSIONS

In the PRC, the prevalence of hypertension is strongly associated with the risk of stroke, and the geographic variation in stroke incidence and mortality is due mainly to differences in the prevalence of hypertension.

[Preparation of oral berberine bisulfate liposomes]

The co-precipitate has been made from berberine bisulfate and polyvingyl pyrrolidone (PVP) with the ratio of 1 : 5. The liposomes entrapped berberine bisulfate have been prepared with the ration of drug to lipid 1 : 20 and the ratio of cholesterol to soy phosphatide 2 : 7. The percentage of encapsulation is 48.72%. The test in vivo of small intestinal absorption in rats shows that liposomes can increase the absorption by 4-fold odd compared with free ber-berine bisulfate.

Purification of a baculovirus-expressed hepatitis E virus structural protein and utility in an enzyme-linked immunosorbent assay

We report on the purification of the full-length structural protein encoded by open reading frame 2 (ORF-2) of hepatitis E virus. The ORF-2 protein, expressed in Sf9 cells by using a recombinant baculovirus vector system, was successfully purified to homogeneity. Gel electrophoresis of the purified ORF-2 protein showed a single polypeptide of 75 kDa by Coomassie blue staining and by Western blot (immunoblot) analysis. We demonstrated that the partially purified ORF-2 protein could be used successfully in a sensitive and specific enzyme-linked immunosorbent assay for the detection of antibodies to hepatitis E virus.

Patterns of blood pressure variability in normotensive and hypertensive rats

We sought patterns in mean arterial pressure of normotensive rats and alterations in chronic hypertension. Pressure was recorded for 4-6 days by telemetry from conscious, unrestrained rats and sampled digitally at 3 Hz, using normotensive Sprague-Dawley rats, spontaneously hypertensive rats (SHR), and Sprague-Dawley rats with two-kidney, one-clip renovascular hypertension (2K,1C). Time series analysis was by fast Fourier transform. Power spectra were divided into ultradian (frequencies > 1/day), circadian (frequency = 1/day), and infradian (frequencies < 1/day) domains. In the ultradian band from approximately 0.1 to 10 mHz the spectra were 1/f and without distinct peaks. The slopes were not significantly different among the groups and ranged from -1.03 to -1.61. At frequencies > 10 mHz, power continued to decrease but with a lower slope. A peak centered at approximately 100 mHz was present in both normotensive and 2K,1C rats but not in SHR. SHR had significantly more ultradian power than the others. The circadian rhythm modulated power in the ultradian band. Modulation was most prominent in normotensives, in which the ultradian activity was highest during the night when rats are active and lowest during the day; less pronounced in 2K,1C; and not detectable in SHR. There are regular patterns of blood pressure fluctuations and specific modifications to the patterns by different forms of hypertension.

Assembly of VP26 in herpes simplex virus-1 inferred from structures of wild-type and recombinant capsids

The 1250 A diameter herpes simplex virus-1 (HSV-1) capsid shell consists of four major structural proteins, of which VP26 (approximately 12,000 M(r)) is the smallest. Using 400 kV electron cryomicroscopy and computer reconstruction, we have determined the three-dimensional structures of the wild-type capsid and a recombinant baculovirus-generated HSV-1 capsid which lacks VP26. Their difference map demonstrates the presence of VP26 hexamers attached to all the hexons in the wild-type capsid, and reveals that the VP26 molecule consists of a large and a small domain. Although both hexons and pentons are predominantly composed of VP5, VP26 is not present on the penton. Based on the interactions involving VP26 and the hexon subunits, we propose a mechanism for VP26 assembly which would account for its distribution. Possible roles of VP26 in capsid stability and DNA packaging are discussed.

Human immunodeficiency virus type 1 viral protein R (Vpr) arrests cells in the G2 phase of the cell cycle by inhibiting p34cdc2 activity

The Vpr accessory gene product of human immunodeficiency virus types 1 and 2 and simian immunodeficiency virus is believed to play a role in permitting entry of the viral core into the nucleus of nondividing cells. A second role for Vpr was recently suggested by Rogel et al. (M. E. Rogel, L. I. Wu, and M. Emerman, J. Virol. 69:882-888, 1995), who showed that Vpr prevents the establishment in vitro of chronically infected HIV producer cell lines, apparently by causing infected cells to arrest in the G2/M phase of the cell cycle. In cycling cells, progression from G2 to M phase is driven by activation of the p34cdc2/cyclin B complex, an event caused, in part, by dephosphorylation of two regulatory amino acids of p34cdc2 (Thr-14 and Tyr-15). We show here that Vpr arrests the cell cycle in G2 by preventing the activation of the p34cdc2/cyclin B complex. Vpr expression in cells caused p34cdc2 to remain in the phosphorylated, inactive state, p34cdc2/cyclin B complexes immunoprecipitated from cells expressing Vpr were almost completely inactive in a histone H1 kinase assay. Coexpression of a constitutively active mutant p34cdc2 molecule with Vpr relieved the G2 arrest. These findings strongly suggest that Vpr arrests cells in G2 by preventing the activation of the p34cdc2/cyclin B complex that is required for entry into M phase. In vivo, Vpr might, by preventing p34cdc2 activation, delay or prevent apoptosis of infected cells. This would increase the amount of virus each infected cell produced.

Lack of p16INK4 or retinoblastoma protein (pRb), or amplification-associated overexpression of cdk4 is observed in distinct subsets of malignant glial tumors and cell lines

In this study the expression of p16INK4, retinoblastoma protein (pRb), and cdk4 proteins have been examined in 18 malignant glioma cell lines and in 45 malignant glial tumors. Loss of p16INK4 expression associated with p16INK4 gene homozygous deletion was evident in 12 cell lines and in 10 primary tumors. Lack of p16INK4 expression was also evident in five tumors for which there was no evidence of p16INK4 gene homozygous deletion. Two of the cell lines and six of the primary tumors in which p16INK4 was present were determined to overexpress cdk4 in association with CDK4 gene amplification. Absence of pRb was determined in two of the cell lines and in ten of the tumors. In total, 16 of 18 cell lines and 25 of 45 tumors showed either a lack of p16INK4 or pRb or amplification-associated overexpression of cdk4. Two additional tumors showed an absence of pRb and p16INK4, and one tumor showed a lack of pRb combined with amplification-associated overexpression of cdk4. These results suggest a common growth-regulatory mechanism that is disrupted in gliomas by either suppressing the expression of p16INK4 or pRb or by increasing the expression of cdk4.

Dietary macronutrients and blood pressure in southwestern China

OBJECTIVES

To study the relationship between dietary macronutrients and blood pressure.

DESIGN

A cross-sectional study.

SETTING

Liangshan, southwestern China.

PARTICIPANTS

Three hundred and twelve Yi farmers living in a remote mountainous area, and 264 Yi migrants and 251 Han people living in an urban setting.

MAIN OUTCOME MEASUREMENTS

Blood pressure and dietary nutrient intake, obtained by asking the subjects to recall their nutrient consumption during the previous 24 h, were measured on three consecutive days.

RESULTS

After adjusting for age, body mass index, alcohol use, urinary excretion of sodium, total energy intake and area of residence and after correcting for the effects of regression dilution bias, a 1 SD higher intake of dietary total protein (39 g) was associated with lower systolic (-3.55 mmHg), and diastolic (-2.16 mmHg) blood pressures. Likewise, a 1 SD higher fiber intake (10 g) was significantly associated both with a lower systolic (-2.20 mmHg) and with a lower diastolic (-2.08 mmHg) blood pressure.

CONCLUSION

Diets higher in protein and fiber content are associated with a lower blood pressure in the present population sample. The present results indicate that dietary intake of macronutrients might be important in the development and prevention of high blood pressure.

Prevalence of antibody to hepatitis E virus among healthy individuals in southern Taiwan

The seroprevalence of hepatitis E virus (HEV) among 997 healthy individuals aged 6 to 84 years, collected between July 1993 and June 1994 at Kaohsiung-Pingtung area in Southern Taiwan was studied. Of the study populations of vegetable farmers, elementary school children, volunteer blood donors and college students, the prevalence of IgG anti-HEV ranged from 6.4% to 8.8%. In suburban elemantary school children of Mang-Chou Village at Pingtung-Hsien, the seroprevalence rate (9.6%) was significantly higher than the positive rate (1.5%) found in rural aboriginal elementary school of San-Min Village at Kaohsiung-Hsien. IgG anti-HEV antibodies were widely distributed among all age groups, with a significantly higher percentage (13.1%) in the age group of 46-55 years old.

The contribution of urinary cations to the blood pressure differences associated with migration

People living in unacculturated societies have a low average blood pressure and little rise in blood pressure with age. In a community-based survey in southwestern China, the authors assessed the contribution of urinary cation excretion to differences in blood pressure between an unacculturated group (Yi farmers) and migrants to an urban environment, as well as urban controls from a different ethnic group (Han). In March 1989, blood pressure and overnight urinary electrolyte levels were measured on 3 consecutive days in 313 Yi farmers, 265 Yi migrants, and 253 urban Han residents, all male. Of the urinary electrolytes, a higher sodium:potassium ratio best explained the higher blood pressure in the migrants. Yi farmers had lower systolic (106.7 mmHg vs. 114.8 mmHg, respectively) and diastolic (66.2 mmHg vs. 71.3 mmHg, respectively) blood pressures than Yi migrants. However, even after adjustment for age, body mass index, alcohol intake, and urinary sodium, potassium, calcium, and magnesium excretion, Yi farmers continued to have lower average blood pressures than Yi migrants. In pooled analyses of all three groups, urinary sodium and calcium were positively related and urinary potassium and magnesium were inversely related to blood pressure. Migration is associated with a higher blood pressure that is only partially explained by higher levels of adiposity and alcohol and sodium intake and lower levels of potassium and magnesium intake.

Use of a novel human immunodeficiency virus type 1 reporter virus expressing human placental alkaline phosphatase to detect an alternative viral receptor

We report here on the construction and use of a novel human immunodeficiency virus (HIV) type 1 reporter vector, HIV-AP, that encodes human placental alkaline phosphatase. Upon staining with chromogenic alkaline phosphatase substrates 24 to 36 h postinfection, cells infected with HIV-AP develop an intense purple color and can then be counted under a dissecting microscope. Alternatively, HIV-AP infectivity can be quantitated and infected cells can be sorted by a fluorescence-activated cell sorter after staining with a fluorescent alkaline phosphatase substrate. The assay is rapid and accurate, has very low background in a variety of cell lines and primary cells, and is not restricted to use in human cells. Infectious HIV-AP can be pseudotyped by various HIV or murine leukemia virus envelope glycoproteins. Using this virus, we have addressed the long-standing question of CD4-independent infection of cells by HIV. Our results confirm the presence on a human osteosarcoma cell line of an alternative receptor for HIV infection that functions with an efficiency approximately 1/20 that of CD4.

Homozygous deletions of the CDKN2 (MTS1/p16ink4) gene in cell lines established from children with acute lymphoblastic leukemia

Homozygous deletions of the CDKN2 (MTS1/p16ink4) gene have been found at high frequency in cell lines derived from a variety of adult solid tumors. In order to investigate the status of the CDKN2 gene in cell lines established from childhood acute lymphoblastic leukemia (ALL), we surveyed 25 lines representing the major pediatric ALL phenotypes for the presence of this gene by Southern blot analysis. Homozygous deletions of all or part of the CDKN2 gene were detected in 21 (84%) cell lines, including 11 of 14 (79%) early-pre-B-ALL, four of five (80%) pre-B-ALL, and six of six T-ALL lines. CDN2 mRNA was detected by Northern blotting in each of the four lines containing an intact CDKN2 gene. These data suggest an important role for CDKN2 deletion in the cause and/or progression of pediatric ALL.

[Preconcentration of trace chromium in natural water with activated carbon and its determination by colorimetry]

The adsorption and desorption behavior of chromium was studied. Trace chromium in water could be adsorbed on activated carbon at pH 9-10, then eluted with 0.5% sulfuric acid and determined by colorimetry. The content of chromium could be concentrated by 100 times. For sample, the coefficient of variation of 8 parallel determinations was 7.7%. The proposed method has been applied to the determination of trace chromium in natural waters with the recovery of 71.4%-90.0%, and with the detection limit of 0.04 microgram/L.

Effect of long-term zidovudine exposure on salvage and de novo purine and pyrimidine nucleotide syntheses

Salvage and de novo purine and pyrimidine nucleotide syntheses were studied in H9 (a human lymphoid cell line) and H9-AZT cells (chronically zidovudine-exposed H9 cells). H9-AZT cells incorporated 18% and 27% more hypoxanthine and uridine, respectively, than H9 cells. The incorporation of the formate and bicarbonate was similar in both cell lines. Purine and pyrimidine de novo synthesis was inhibited by hypoxanthine and uridine, respectively. Hypoxanthine and uridine salvage pathways, however, were not affected by formate or bicarbonate. Short-term AZT exposure of cells had no effect on nucleotide synthesis. Some of the problems encountered in the studies of purine and pyrimidine synthesis are also discussed.

Radiotherapy of ectopic ACTH syndrome due to thoracic carcinoids

From 1984 to 1990, six patients with histologically and endocrinologically proven ectopic ACTH syndrome were treated in our department. The lesion in five patients was clinically evident, but in the other was occult. All lesions were located within the chest. Four were thymic carcinoid and the other two were bronchial carcinoids. Most of the patients had typical clinical manifestations of Cushing's syndrome. Laboratory tests including histopathological examination confirmed the diagnosis of ectopic ACTH syndrome. The treatment consisted of surgical removal of the mass supplemented by radiotherapy. The results showed that after treatment all patients had satisfactory remission. Two bronchial carcinoid patients have been living for 40 and 88 months respectively without recurrence. Among 4 thymic carcinoid patients, only one has been living with no tumor for 34 months. One patient had recurrence and the other 2 died 32 and 50 months after the treatment respectively. However, the symptoms of two thymic carcinoid patients had not been relieved at all until radiotherapy was given. This paper discusses the method, dose and indications of radiotherapy. It should be pointed out that the prognosis of bronchial carcinoids is good while that of thymic carcinoids is relatively poor.

Altered subcellular location of an activated and tumour-associated epidermal growth factor receptor

The epidermal growth factor (EGF) receptor is a membrane bound tyrosine kinase whose activity is initiated by ligand binding. The malignant brain tumour glioblastoma frequently shows amplification and rearrangements of the EGF receptor gene that are associated with the synthesis of a constitutively activated tyrosine kinase, lacking amino acids 6-273 near the protein's N-terminus. When expressed in Chinese hamster ovary (CHO) cells, this mutant receptor (p140EGFR) displays ligand-independent tyrosine kinase activity, stimulates DNA synthesis, and promotes cell proliferation. Here, we investigate the subcellular location of p140EGFR in CHO cell transfectants as well as in human glioblastoma tumours. p140EGFR had an intracellular location that contrasted sharply with the plasma membrane location of the wild-type EGF receptor. Endoglycosidase H sensitivity analysis and the pattern of p140EGFR immunoreactivity suggested that the aberrant tyrosine kinase resided primarily in the endoplasmic reticulum. The half-life of p140EGFR in the endoplasmic reticulum was extended several-fold over that of the ligand-activated wild-type receptor. The altered subcellular location of p140EGFR in combination with its prolonged half-life suggest that this activated tyrosine kinase may escape the regulatory mechanisms utilized for the attenuation of wild-type receptor signaling. Therefore, the previously reported growth stimulatory property of the ligand-independent p140EGFR may be attributed to a sustained tyrosine kinase activity resulting from an altered subcellular location.

Exercise-induced changes in R wave amplitude and heart rate in normal subjects

An intermittent exercise protocol on a treadmill was used to examine six healthy subjects, and a steady protocol was applied to three of the subjects before and after short-term training. The peak blood velocity in the common carotid artery increased by 73.1% during the intermittent protocol and recovered to resting level within 3 minutes, while the heart rate (HR) remained high even 5 minutes after exercise. R wave amplitude (RWA) increased significantly from 1.40 +/- 0.39 mV at rest to 1.59 +/- 0.33 mV (P < .05) immediately after the start of walking, and decreased gradually to 1.46 +/- 0.36 mV (P < .05) during 3 minutes of walking. Thus, it decreased significantly to 1.31 +/- 0.40 mV (P < .01) during the interphase from exercise to rest, and increased again during recovery or rest periods in the intermittent protocol. The results suggest that an increase in the venous return per heart beat at the start of walking induces the increase in RWA, and that its abrupt decrease at the end of walking induces the decrease in RWA. Subjects with a higher HR response and recovery slopes have smaller abrupt changes in RWA at the interphases between rest and walking. The gradual decrease in RWA during walking may be related to a gradual increase in HR and a gradual decrease in systemic peripheral resistance, and the gradual increase in RWA after walking may be related to a gradual decrease in HR and a gradual increase in systemic peripheral resistance.

Histidine ameliorated brain edema and cardiac dysfunction during local thrombotic cerebral ischemia in rats

AIM

To observe the effects of histidine (i.v. 5 mg.kg-1) on brain edema and cardiac disturbance after cerebral thrombosis.

METHODS

Regional cerebral thrombosis was induced by photochemical method in rats.

RESULTS

It was showed that the brain water content increased markedly (85.6 +/- 3.8%, P < 0.01); the left ventricular systolic pressure (LVSP, 17.9 +/- 1.5 kPa) and the maximal left ventricular contractility decreased (+dp/dtmax 645 +/- 110 kPa and -dp/dtmax 473 +/- 106 kPa, P < 0.05). In rats treated with histidine after photochemical reaction, the brain water content decreased (81.5 +/- 2.0%) while LVSP (21.2 +/- 1.1 kPa) and left ventricular +dp/dtmax and -dp/dtmax increased markedly (777 +/- 144 kPa and 604 +/- 157 kPa, respectively).

CONCLUSION

Histidine has protective effects on the brain and cardiac function during cerebral thrombosis.

Sequence specificity and transcriptional activation in the binding of lactoferrin to DNA

Lactoferrin, an iron-binding glycoprotein found in high concentrations in human milk and other epithelial secretions and in the secondary (specific) granules of neutrophils, is thought to be responsible for primary defence against microbial infection, mainly as a result of lactoferrin sequestration of iron required for microbial growth. Many other functions have been attributed to lactoferrin, including immunomodulation and cell growth regulation (reviewed in ref. 4). Some of these functions appear to be at least in part independent of the iron-binding activity of lactoferrin. It also has been consistently observed that lactoferrin interacts avidly with nucleic acids. Lactoferrin enhancement of the activity of natural killer and lymphokine-activated killer cells in vitro is inhibited by RNA and DNA. Lactoferrin taken up by K562 human myelogenous leukaemia cells appears in the nucleus where it is bound to DNA. We report here that binding of lactoferrin to DNA occurs under stringent conditions with distinct sequence specificity, and that interaction between lactoferrin and these sequences intracellularly leads to transcriptional activation.