An improved ELISA with linear sweep voltammetry detection

An improved ELISA combined with linear sweep voltammetry detection of p-nitrophenol generated by an enzyme has been investigated in this study. p-nitrophenol, produced from alkaline phosphatase catalysing p-nitrophenyl phosphate, yielded an oxidative peak at 1.06 V (vs. Ag/AgCl) with a wax-impregnated tubular graphite anode. Without separation, the small three-electrode system was directly inserted in the well of an ELISA plate for detection. The detection limit for p-nitrophenol was 1 x 10(-6) M, lower than that obtained by measuring the absorbance of p-nitrophenol. The feasibility of utilizing linear sweep voltammetry as a detection scheme was demonstrated by determining metallothionein, granulocyte-colony stimulating factor and Xenopus laevis keratin using the above new system. The method was simple, reproducible and much more sensitive than traditional spectrophotometry.

2-Amino-3-(methylamino)propanoic acid (BMAA) bioavailability in the primate

2-Amino-3-(methylamino)-propanoic acid (BMAA) is a low potency excitatory amino acid present in the cycad plant that has been proposed as a factor in the high incidence of amyotrophic lateral sclerosis-parkinsonism dementia (ALS-PD) in the western Pacific region. We employed stable isotopic forms of BMAA to assess the oral bioavailability of this compound in cynomolgous monkeys (n = 3). The stable isotope labeled BMAA ([15N]-BMAA) was injected i.v. at the same time that the unlabeled compound was administered orally. Both forms of BMAA were then quantified in a 48h urine sample by gas chromatography-mass spectrometry (GC/MS). Following oral dosing, 80% of the administered BMAA was absorbed into the systemic circulation; thus, oral bioavailability was high and other routes of administration could not result in significantly higher circulating levels of BMAA for a given administered dose.

Antagonism of l-stepholidine on D2 receptor-mediated inhibition of synaptosomal adenylate cyclase in rat corpus striatum

In the presence of Sch 23390 0.1 mumol.L-1, dopamine (DA) inhibited the activity of synaptosomal adenylate cyclase (AC) isolated from rat striatum in a concentration-dependent manner with IC50 value of 2.2 mumol.L-1. The maximal inhibition corresponded to a 51% decrease of basal enzyme activity and was obtained at DA 100 mumol.L-1. The inhibitory effect of DA was reversed by selective D2 receptor antagonist spiperone 10 mumol.L-1. N-0437, a selective D2 DA receptor agonist also inhibited the activity of AC in the manner similar to that of DA. Both the inhibitions induced by DA and N-0437 were antagonized by l-stepholidine (l-SPD). However, in the presence of Sch 23390, l-SPD alone also inhibited the activity of AC by 29% and 33% at the concentrations of 10 and 100 mumol.L-1, respectively. The inhibition of l-SPD on AC activity was significantly antagonized by spiperone. In the presence of Sch 23390, both DA and N-0437 increased the activity of high affinity GTP phosphohydrolase in striatal synaptosomes. The increases of GTP phosphohydrolase activity stimulated by DA and N-0437 were completely reversed by l-SPD 100 mumol.L-1. These results suggest that l-SPD antagonizes or reverses the D2 receptor-mediated inhibition of AC activity through affecting the regulation of Gi (inhibitory guanine nucleotide-dependent protein) on D2 receptor-coupled AC and therefore affects the negative feedback of presynaptic DA receptors. Moreover, the inhibition of AC activity induced by l-SPD alone may provide a useful biochemical index for dual action of l-SPD.

Electroretinographic oscillatory potentials in diabetic retinopathy. An analysis in the domains of time and frequency

The oscillatory potentials of the electroretinogram in dark and light adaptation were evaluated by Fourier transform in 87 diabetics and 74 age-matched controls. The study consisted of four groups: normal control, no observable diabetic retinopathy, background diabetic retinopathy and proliferative diabetic retinopathy. A reduction in the amplitude of each oscillatory potential, the summed amplitudes, the area and the total power of the oscillatory potentials as well as delayed implicit time of each oscillatory potential peak in dark and light adaptation could be found in patients with background diabetic retinopathy and proliferative diabetic retinopathy. The amplitude of oscillatory potential 4 in dark adaptation and the total power of the oscillatory potentials in light adaptation seemed to be affected in patients with no observable diabetic retinopathy. The implicit time of oscillatory potential 2 in dark adaptation was valuable to distinguish between patients with no observable diabetic retinopathy and background diabetic retinopathy.

[A case-control study on risk factors of female hypertension in Tianjin City]

A pair matched case-control study was conducted in 301 pairs female patients with essential hypertension and their controls. The data was analysed by the multiple conditional Logistic regression. The results showed the risk factors associated with hypertension were: body weight (OR = 1.17, 95% CI: 1.12-1.23), the family history of hypertension (OR = 2.18, 95% CI: 1.49-3.21) the family income (OR = 0.73, 95% CI: 0.56-0.94), heart rate (OR = 2.30, 95% CI: 1.41-3.76). OR for the age of menarche was significantly different before and after being adjusted by body weight. There were no relationship between the age of menopause, the age of the first birth, parties, oral contraceptive use or smoking status and hypertension. The paper suggested that the difference of prevalence of hypertension in male and female over 45 years old cannot be explained by menopause or the factors on birth in women.

A histological, ultrastructural and immunohistochemical study of superficial temporal arteries and middle meningeal arteries in moyamoya disease

Pathologic changes in superficial temporal arteries (STA) and middle meningeal arteries (MMA) biopsied from 15 patients with moyamoya disease (MD) who had undergone cerebro-temporal arterio-synangiosis were studied histologically, ultrastructurally and immunohistochemically. The main pathologic features were: proliferation of smooth muscle cells (SMCs) and thickening of the intima, degeneration and destruction of SMCs in the media and intima, and the presence of condensed organelles in necrosed SMCs or the interstitium among SMCs, or both outside and within the elastica interna (EI). The EI had become thin, porous, fragmented and was even absent in some segments. These changes are different from those of other forms of angiopathy, but identical with those at the ends of internal carotid arteries (ICA) reported by us previously, being pathognomonic for MD. These changes in the STA and MMA reveal that MD involves not only the ICA but also the intra- and extracranial branches of external carotid arteries. The medial necrosis of SMCs seems to be the primary injury of the arterial wall in MD. STA tissue blocks from two cases of MD were stained immunohistochemically. By electron microscopy, IgG-, IgM-, and C3-positive granules were observed on the ER of endothelial and intimal cells. Further studies on more cases are needed to determine whether an immunoreaction has occurred in these arteries.

Uterine influences on the formation of subnormal corpora lutea in seasonally anestrous ewes

The hypothesis that subnormal luteal function after induced ovulation in anestrous ewes was the result of uterine influences exerted during the periovulatory period was tested. Crossbred ewes (n = 27) in seasonal anestrus were induced to ovulate by administration of 12 doses of 250 ng of LHRH at 2-h intervals, followed immediately by a bolus injection of LHRH (250 micrograms; d 0). Ewes were unilaterally hysterectomized on either d -3 (PRELHRH) or 2 (POSTLHRH). Daily blood samples were collected and assayed for progesterone (P4) and 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM). All ewes were slaughtered on d 10, and corpora lutea (CL) were collected, weighed, and assayed for concentration of P4. All ewes that ovulated exclusively in the ovary ipsilateral to the remaining uterine horn had a transient increase in plasma P4 of 2 to 3 d (short luteal phase). In ewes with at least one CL in the isolated ovary, elevated plasma P4 was maintained after hysterectomy but was consistently lower (P less than .05) in POSTLHRH ewes than in PRELHRH ewes. Concentrations of PGFM did not differ between treatments. The CL ipsilateral to the remaining uterine horn weighted less (P less than .01) and contained less P4 (P less than .01) than contralateral CL. These data confirm the hypothesis that premature regression of subnormal CL is uterine-dependent in a local fashion. Presence of the uterus during the follicular and(or) early luteal phase inhibited subsequent luteal function in seasonally anestrous ewes.

Resistance to trimethoprim in Haemophilus influenzae

The mechanisms of resistance to trimethoprim in eleven U.K. clinical isolates of Haemophilus influenzae were studied. The levels of dihydrofolate reductase (DHFR) activities in crude extracts from four resistant wild-types were similar to those in susceptible controls. However, activities in extracts from the other seven resistant wild-type isolates, and transformants of two of these, were at least triple those in the sensitive strains. Resistance to trimethoprim was also selected for in vitro during prolonged exposure to the drug and was associated with increased levels of DHFR specific activity in the mutants. DHFR enzymes were, however, still very susceptible to inhibition by trimethoprim. Activities in four extracts, including one from a transformant of a resistant mutant, were reduced by at least 45% following incubation with 10(-8) M trimethoprim. The results suggested that overproduction of the chromosomal DHFR enzyme may be the resistance mechanism in some organisms. The much lower DHFR activities measured in extracts from other resistant isolates may reflect synthesis of chromosomal enzymes that have reduced susceptibility to trimethoprim.

Effects of hyperlipidemic sera and lipoproteins on prostacyclin synthesis by rabbit aortic smooth muscle cells

The effects of various hyperlipidemic sera and serum high density lipoproteins (HDL) and low density lipoproteins (LDL) on the synthesis of prostacyclin (PGI2) by rabbit aortic smooth muscle cells in culture were studied. Data show that HDL induces a dose-dependent increase in the synthesis of PGI2 in smooth muscle cells. Although LDL at comparable cholesterol concentrations to HDL also results in an increase of PGI2 synthesis in a dose-dependent pattern, the extent of this increase is much less than that induced by HDL. Smooth muscle cells incubated with hyperlipidemic serum and hyperlipidemic + aspirin-treated sera synthesize less PGI2 as compared to normal serum, but cells incubated with hyperlipidemic + 8501-treated serum generate an amount of PGI2 similar to that seen with normal serum. We suggest that 8501 may directly stimulate PGI2 synthetase in smooth muscle cells.

Clinical and experimental observations on treatment of peptic ulcer with wei yang an (easing peptic-ulcer) capsule

The therapeutic effects of peptic ulcer treated with cimetidine and Wei Yang An were compared clinically and experimentally by the double blind method. Results showed that the effects of the two are similar, but the long-term effect of Wei Yang An was better. Wei Yang An was also good for most cimetidine resistant ulcers, with few side effect. Animal experiment showed that Wei Yang An inhibited the ulcers.

[Differentiation of Magnolia denudata Desr. flower buds]

The article gives the results of an observation on the differentiation of Magnolia denudata buds. In Huaining County, Anhui Province, differentiation of the buds starts at the beginning of May. By the end of June the differentiation of various parts of the flower is completed. The process takes about 50 days. The differentiation of buds goes on at a fairly fast speed and in a fairly uniform way. Based on the results of the observation, the authors advise that application of fertilizer, especially the top application should not be late. The beginning of March is a very important time for the development of buds in length and size, and for the final harvest as well. The proper time to pick the flower buds comes when they are fully developed before the perianth appears.

Amelogenin post-secretory processing during biomineralization in the postnatal mouse molar tooth

The primary structures, molecular genetics and biosynthesis of the amelogenin protein of the developing tooth are established, but knowledge of their subsequent post-secretory processing and its relation to enamel biomineralization is fragmentary. Preparations of tooth matrix proteins were isolated from molars (M1) of mice from birth to 15 days and analysed by SDS-PAGE and immunochemical methods. Amelogenin proteins, isolated and partially purified by HPLC, were characterized by amino acid analysis and SDS-PAGE. At birth a 26 kDa amelogenin was present that during subsequent developmental stages generated a series of 20-25 kDa amelogenins differing in apparent size by approximately 1 kDa. Amino acid analyses showed that all these amelogenins have amino-terminal TRAP sequences; analyses for both glycosylation and phosphorylation were negative. It is suggested that these post-secretory amelogenins are generated by a sequence of specific carboxy-terminal cleavages, and that the observed post-secretory processing of amelogenin is functionally linked to the structure of the enamel matrix and the control of crystallite development.

[Preparation, identification and functional studies on liposome (ApoA-I:PC)]

Liposome (ApoA-1: PC) was prepared by the deoxycholic acid dialysis method and identified by agarose gel electrophoresis, two dimensional thin-layer chromatography and electron microscopy. The purified liposomes manifested one band in Amino black 10B staining and no color in Oil red O staining due to the presence of phospholipid. Only one brown spot appeared in two dimensional TLC, and electron microscopy with 1% sodium phosphotungstate negative staining revealed discoidal shapes stuck together. All of the above indicate that the liposome consisted of ApoA-1 and PC. Liposomes were added to the medium of smooth muscle cell cultures and then LDL receptor expression and cholesterol efflux from the cells were observed. The results suggest that the ApoA-1:PC can enhance the expression of LDL receptors indirectly by stimulating cholesterol efflux from the cells.

[Studies on the toxicity of a new synthetic drug SC1001-aminum]

SC1001A is a new sedative, hypnotic and anti-epileptic drug. Screening for possible mutagenicity of the agent consisted of a battery scheme of short-term mutagenic tests with different hereditary detecting end points. Three assays were with in the scheme: Ames test (for detecting gene mutation in vitro), micronucleus test (for detecting chromosomal aberration in vivo) and CHL (Chinese hamster lung cell line) test (for detecting chromosomal aberration in vitro). In addition, a routine teratogenicity study on SC1001A was carried out in mice. They were given daily at 3-dose levels (exposed to up to 33% of the LD50 by gastric incubation from the 6th through the 15th day of gestation. SC1001A gave uniformly negative results in all three mutagenic assay systems. Results of the teratogenic experiment showed that only the pregnant rate in bred mice in the moderate dose group and the mean maternal body weight gain of the dams during gestation in the low dose group were significantly lower than those in the corresponding control group. A clear dose-response relationship was not demonstrated. All dose levels of SC1001A used caused no adverse effects on the number of survival fetuses per litter, growth or development of the fetal mice. No malformations in the external appearance, of the internal organs and of the skeletal systems in fetal mice were observed. The above-mentioned results indicated that SC1001A induced neither gene mutation nor chromosomal damage both in vitro and in vivo. There was no evidence of teratogenesis. Therefore, it is estimated that SC1001A is probably comparatively safe as a pharmaceutical product for human beings in usual dosage.

Regulation of luteinizing hormone secretion in prepubertal heifers fed an energy-deficient diet

The effects of feeding a diet restricted in energy on the endocrine mechanisms regulating LH secretion in prepubertal heifers were examined. On Day 0, thirty heifers were assigned to be either ovariectomized (OVX; n = 10), ovariectomized and administered an estradiol implant (OVXE; n = 10), or to remain ovary-intact (INT, n = 10). Five heifers each were then assigned to be fed either a control (C) or a two-phase, low-to-high energy (L), dietary treatment. The C diet was formulated to support weight gains of 1.1 kg/day throughout the experiment (Day 0-197). Heifers receiving the L treatment were provided a diet restricted in energy (33% of C diet) from Day 0-127 followed by a diet similar to that fed to heifers receiving the C treatment from Day 128-197. Secretion of LH increased rapidly following ovariectomy in C-OVX and L-OVX heifers. During the period of energy restriction, LH pulse frequency was reduced, and mean LH concentration, pulse amplitude, and pituitary response to LHRH were greater in L-OVX than in C-OVX heifers. In L-OVXE and L-INT heifers, secretion of LH was low and unchanged during the period of dietary energy restriction. In contemporaneous treatment groups fed the C diet (C-OVXE and C-INT), frequency of LH pulses increased gradually during this period and C-INT heifers attained puberty on Day 121 +/- 18. Upon switching heifers in the L-OVX, L-OVXE, and L-INT treatments to the C diet, all characteristics of LH secretion changed markedly within 14 days to levels similar to those detected in the C treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cloprostenol sodium and clenbuterol HCl on reproductive performance in postparium anestrous cows

Two experiments were conducted to study effects of cloprostenol sodium (cloprostenol) and clenbuterol HCl (clenbuterol) during postpartum anestrus on subsequent reproductive performance in cows. In Experiment I, 96 cows received either 0.5 mg cloprostenol (PGF, n = 25), 364 mg clenbuterol (CLEN, n = 24), 0.5 mg cloprostenol and 364 mg clenbuterol (CLEN+PGF, n = 21) or no treatment (Control, n = 26) on Day 20 post partum. Treatments failed to influence postpartum interval, pregnancy rate or the incidence of short estrous cycles preceding the first normal estrous cycle. In Experiment II, anestrous cows were administered cloprostenol (0.5 mg) on either Day 20 (PGF20, n = 27) or Day 35 post partum (PGF35, n = 25), or served as untreated controls (Control, n = 26). Neither postpartum interval nor pregnancy rate were affected by cloprostenol treatment. In conclusion, treatment of postpartum cows with PGF did not alter the resumption of normal estrous cycles following parturition.

[An epidemiological survey of gallstones with gray-scale ultrasound]

Gray-scale real-time ultrasound has been employed to investigate gallstone with a positive result of 553 cases out of 15,856 healthy subjects in city and countryside, the incidence being 34.88%. The feature of incidence is as follows: 1. The incidence of the simple gallbladder stone is more common than that of the other sites (male is about 81.15%, female is about 87.29%); 2. The incidence of gallstones of city residents is higher than that of the country people with significant difference statistically (P less than 0.01); 3. The incidence of gallstone in female city residents is higher than male, about 2.5:1, which shows significant difference. (P less than 0.01); 4. The incidence of gallstones in female city residents is higher than in countryside (P less than 0.01); 5. There is no significant difference in the incidence of gallstone between male and female in the countryside (P greater than 0.05); 6. There is no significant difference in the incidence of gallstones between city male and the male in the countryside (P greater than 0.05); 7. Either in the city or in the countryside, it has been shown that there is a tendency of increasing incidence of gallstone with age in both sexes (P less than 0.01). The relationship between the gallstone and the clinical symptoms has been discussed in this paper.

Optical characterization of thin films by guided waves

The study of guided waves in a thin layer allows a precise characterization of refractive index and thickness. Optical anisotropy can also be measured. We show how this technique can be applied to the characterization of a multilayer structure.

Surface optical coatings by ion assisted deposition techniques: study of uniformity

Uniformity of layers produced by IAD strongly depends on the characteristics of the ion beam: optical characterization is made by guided wave measurements. The thickness and refractive index including anisotropy must be considered separately to interpret the measured uniformity.

The central projections of the great auricular nerve primary afferent fibers--an HRP transganglionic tracing method

A study of the central distribution of the primary afferent fibers of the great auricular nerve (GAN) was made in 18 rabbits by means of transganglionic transport of horseradish peroxidase (HRP). HRP applied to the cut central end of the GAN was detected ipsilaterally in the dorsal root ganglion cells (segments C2-C3) and the superior cervical ganglion cells. The transganglionically labeled fibers were seen in the dorsal column of the upper 4 cervical segments and in the cranial nerve nuclei of the medulla oblongata. The afferent projections were rather strong in the regions of laminae I-V of C2, the caudal subnucleus of the nucleus of the spinal tract of the trigeminal nerve (NVSpc), the solitary nucleus (SN), the medial and lateral cuneate nuclei, etc. The results showed that the primary afferent impulses of the GAN and the peripheral nerves which supply the head, face, trunk and viscera might converge on the upper cervical cord, the NVSpc and the SN, and play a certain role of modulation on the transmission of somaticovisceral sensations, especially pain.

Restoration of longitudinal images

In this paper, a method of restoring longitudinal images is developed. By using the transfer function for longitudinal objects, and inverse filtering, a longitudinal image may be restored. The Fourier theory and sampling theorems for transverse images cannot be used directly in the longitudinal case. A modification and reasonable approximation are introduced. We have numerically established a necessary relationship between just-resolved longitudinal separation (after inverse filtering), noise level, and the taking conditions of object distance and lens diameter. An empirical formula is also found to well-fit the computed results. This formula may be of use for designing optical systems which are to image longitudinal details, such as in robotics or microscopy.

Patterns of mortality differentials by marital status in low mortality countries

"This study examined mortality differentials by marital status in 11 low-mortality countries [for the period 1950-1980]. The results show that, in general, unmarried populations have a higher mortality rate than that of married populations. A more detailed analysis indicates that each country has its distinctive marital mortality features which are associated with cultural regions (East and West) but are not related to developmental factors. When marital mortality patterns of the East and West are compared, it demonstrates that mortality rates of never-married Asian women are strikingly higher than that of their Western counterparts. This phenomenon has persisted during the last two decades. Two possible cultural interpretations are suggested: differential family support theses versus differential marital selection." (SUMMARY IN CHI)