[Low-molecular-weight chromium-binding substances in hepatic and nephric tissues of chromium-exposed rats]

Male Wistar rats were injected intraperitoneally with potassium dichromate(2.55 mg Cr6+ per kg body weight) for 7 days, and were observed continuously for 7 days after stopping Cr injection. The results were that concentrations of chromium-binding substances (HMW-Cr, LMW-Cr, and MMW-Cr) increased significantly with the extension of Cr injection time; MMW-Cr was not found in the control group. MMW-Cr may be a valuable indicator in diagnosing chromium toxication. It was efficient to use Sephadex G-50 column chromatography and ultra-violet absorption spectrometry-atomic absorption spectrophotometry in isolation, and then it was followed by quantitative analysis of chromium-binding substances.

Fabrication of compact silver nanoshells on polystyrene spheres through electrostatic attraction

Nanoshells composed of close-packed silver nanocrystals have been fabricated on polystyrene spheres via direct electrostatic attraction at appropriate pH; the thickness and roughness of the shell can be readily controlled through a layer-by-layer technique.

Evidence that APC regulates survivin expression: a possible mechanism contributing to the stem cell origin of colon cancer

Because colorectal cancers (CRCs) frequently display APC mutation, inhibition of apoptosis, and increased expression of the antiapoptotic protein survivin, we hypothesized that APC mutation inhibits apoptosis by allowing constitutive survivin expression. Using HT-29 CRC cell lines having inducible wild-type APC (wt-APC) or transfected dominant-negative TCF-4, we show that wt-APC down-regulates survivin expression via APC/beta-catenin/TCF-4 signaling. Using normal colonic epithelium, we found survivin by immunostaining/reverse transcription-PCR to be preferentially expressed in the lower crypt (which inversely correlates with wt-APC's expression pattern). Thus, wt-APC, by progressively decreasing survivin and increasing apoptosis from crypt bottom to top, may limit the population size of stem cells and other proliferative cells in the lower crypt; mutant APC may allow expansion of these populations, thereby initiating tumorigenesis.

[Accurate diagnosis of stages of hepatic fibrosis by measuring levels of serum hyaluronic acid, procollagen type III, and collagen type IV]

OBJECTIVE

To study the accurate diagnosis of various stages of hepatic fibrosis by measuring serum hyaluronic acid (HA), procollagen type III (PC III), and collagen type IV (CIV).

METHODS

The concentrations of serum HA, PC III, CIV in 253 patients with chronic liver disease were measured by radioimmunoassay. Liver biopsies were performed in all of the patients at the same time. According to the results of liver pathological diagnosis, we assessed the ability of serum HA, PC III and CIV to identify correctly patients with hepatic fibrosis (staging >or=S(2)) or cirrhosis (S(4)).

RESULTS

The cutoff value of HA, PC III and C IV to identify correctly patients with hepatic fibrosis was 90 microg/L, 90 microg/L, 75 microg/L respectively. The sensitivity (Se) was 80.4%, 82%, 63.1%; the specificity (Spe) was 70.2%, 60.8%, 83.8%; the positive prediction value (PPV) was 86.7%, 83.5%, 90.4%; the negative prediction value (NPV) was 59.8%, 58.4%, 48.4%, respectively. The cutoff value to identify patients with cirrhosis was: HA 210 microg/L, Se 96.2%, Spe 85.3%, PPV 65.4%, NPV 98.8%; PC III 150 microg/L, Se 76.4%, Spe 68.7%, PPV 40.4%, NPV 91.3%; C IV 90 microg/L, Se 80%, Spe 75.8%, PPV 47.8%, NPV 93.2%, respectively.

CONCLUSIONS

The determination of serum HA, PC III and C IV can make relatively accurate diagnosis to various stages of hepatic fibrosis. HA is the best for diagnosis of liver cirrhosis.

[Effect of total flavones of Hippophae rhamnoides L. on sympathetic activity in hypertension]

OBJECTIVE

To investigate the effect of total flavones of hippophae rhamnoides L (TFH) on sympathetic nerve activity of essential hypertensive patients and to determine whether TFH possesses inhibitory effect on sympathetic activity after supine isometric exercise.

METHODS

Heart rate, blood pressure and plasma catecholamines of the patients were measured before and after treatment. 88 patients were randomly divided into TFH group (n = 35), calcium antagonist nifedipine (n = 33) and verapamil ER (n = 20) group.

RESULTS

It was shown after 8 weeks of treatment that TFH did not alter the rest heart rate and plasma catecholamine concentration in the patients (P > 0.05). In contrast, nifedipine produced an increase of noradrenaline and adrenaline level(P < 0.01). Isometric exercise may significantly increase the heart rate, blood pressure and plasma catecholamine concentration in hypertensive patients. In TFH group, exercise did not increase the heart rate, blood pressure and plasma catecholamine concentration after treatment. In nifedipine group, however, the same isometric exercise significantly increased the heart rate, blood pressure and noradrenaline concentration after treatment (P < 0.01). In verapamil group, the plasma catecholamine concentration did not change after treatment, but it was significantly increased after isometric exercise.

CONCLUSIONS

The results suggest that TFH does not alter the sympathetic activity in treatment of hypertension and the inhibitory effect of TFH on sympathetic activity after supine isometric exercise may provide clinical benefits.

Up-regulation by IGF-I of proliferating cell nuclear antigen and Bcl-2 protein expression in human uterine leiomyoma cells

IGF-I has been reported to play a role in regulating proliferation of human leiomyoma cells. There is, however, little evidence to suggest that IGF-I inhibits apoptosis in the leiomyoma cells. The present study was conducted to elucidate whether IGF-I affects apoptosis and Bcl-2 protein expression, an apoptosis-inhibiting gene product, in cultured leiomyoma cells. In addition, we examined the effect of IGF-I on proliferating cell nuclear antigen (PCNA) expression in cultured leiomyoma cells. Isolated human leiomyoma cells were subcultured in phenol red-free DMEM supplemented with 10% FBS for 120 h and then stepped down to serum-free conditions for an additional 72 h in the absence or presence of graded concentrations of IGF-I (1.0, 10, and 100 ng/ml). The effects of IGF-I on Bcl-2 protein and PCNA expression in cultured leiomyoma cells were assessed by Western immunoblot analysis and immunocytochemical staining, whereas the effects of IGF-I on the cell viability and apoptosis of the cultured cells were determined by 3-(4,5-dimethylatriazol-2-yl)-2,5diphenyltetrasodium bromide (MTT) assay and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling assay, respectively. Immunocytochemical staining demonstrated that IGF-I treatment resulted in the increase in PCNA labeling index in cultured leiomyoma cells in a dose-dependent manner. Immunoblot analysis of proteins extracted from the cultured leiomyoma cells revealed that the addition of IGF-I (10 and 100 ng/ml) significantly increased the expression of 35-kDa immunoreactive PCNA and 26-kDa Bcl-2 protein, compared with those in control cultures. Cell survival and proliferation of cultured leiomyoma cells, assessed by MTT assay, was significantly augmented by IGF-I treatment, compared with those of control cultures. Terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling assay showed that the apoptosis-positive rate of leiomyoma cells treated with IGF-I was significantly decreased, compared with that in control cultures. The present results suggest that IGF-I plays crucial roles in leiomyoma cell growth, not only in promoting the proliferative potential by up-regulation of PCNA expression but also in down-regulating apoptosis by up-regulation of Bcl-2 protein expression in leiomyoma cells.

A soluble class II cytokine receptor, IL-22RA2, is a naturally occurring IL-22 antagonist

IL-22 is an IL-10 homologue that binds to and signals through the class II cytokine receptor heterodimer IL-22RA1/CRF2-4. IL-22 is produced by T cells and induces the production of acute-phase reactants in vitro and in vivo, suggesting its involvement in inflammation. Here we report the identification of a class II cytokine receptor designated IL-22RA2 (IL-22 receptor-alpha 2) that appears to be a naturally expressed soluble receptor. IL-22RA2 shares amino acid sequence homology with IL-22RA1 (also known as IL-22R, zcytor11, and CRF2-9) and is physically adjacent to IL-20Ralpha and IFN-gammaR1 on chromosome 6q23.3-24.2. We demonstrate that IL-22RA2 binds specifically to IL-22 and neutralizes IL-22-induced proliferation of BaF3 cells expressing IL-22 receptor subunits. IL-22RA2 mRNA is highly expressed in placenta and spleen by Northern blotting. PCR analysis using RNA from various tissues and cell lines showed that IL-22RA2 was expressed in a range of tissues, including those in the digestive, female reproductive, and immune systems. In situ hybridization revealed the dominant cell types expressing IL-22RA2 were mononuclear cells and epithelium. Because IL-22 induces the expression of acute phase reactants, IL-22RA2 may play an important role as an IL-22 antagonist in the regulation of inflammatory responses.

[Vasonatrin peptide attenuates hypoxia-induced increase in [Ca(2+)] (i) of culured rat cardiac fibroblasts]

The purpose of this work was to test the hypothesis that vasonatrin peptide (VNP) can attenuate the growth-promoting effect by hypoxia in cardiac fibroblasts of cultured neonatal rats. Cultured fibroblasts were divided into four groups: control group, hypoxia group, VNP group and VNP+hypoxia group. The growth of cardiac fibroblasts was observed using MTT method and the incorporation of (3)H-TdR, and the effect of VNP on the intracellular level of Ca(2+) was measured by means of interactive laser cytometry. It was found that hypoxia (2% - 3%) increased significantly the MTT optical density (OD) of cardiac fibroblasts (P<0.05 vs control group), but the increase was greatly attenuated in the VNP (10(- 6)mol/L) group and also the incorporation of (3)H-TdR in cardiac fibroblasts (P<0.05 vs hypoxia group). VNP (10(- 6)mol/L) also decreased the intracellular level of Ca(2+) which was increased by hypoxia (P<0.05) as compared with control and hypoxia group. These findings demonstrate that VNP can attenuate the hypoxia-induced growth-promoting effect in cardiac fibroblasts, which may be associated with the elevation of intracellular Ca(2+).

Influence of bromide on electrochemistry of photosynthetic reaction center films on gold electrodes

A strong influence of bromide ion was found on voltammetry of layered films of photosynthetic reaction center (RC) protein and polyions on gold electrodes. Similar, but not identical, cyclic voltammetry peaks were observed for polyion films on gold with and without RC when the buffer solutions contained bromide ion. CVs of RC films were quite different in the absence of bromide. These new findings suggest that previously published results were biased by significant background peaks involving bromide ion adsorption/desorption.

[The influence of recombinant human growth hormone on the metabolism of glucose and protein in severely burned patients]

OBJECTIVE

To investigate the influence of recombinant human growth hormone (rhGH) on the metabolism of glucose and protein in severely burned patients.

METHODS

The serum levels of total protein and albumin and the incidence of hyperglycemia in 24 cases of severely burned patients treated by rhGH were determined and compared with those in patients without rhGH treatment (control group).

RESULTS

The serum levels of total protein (TP) and albumin in burned patients after being treated by rhGH were much higher than those before treatment and those in control group. The blood level of glucose increased within 2 weeks, especially 1 week postburn. The incidences of hyperglycemia were 52.38%, 50.24% and 20% on 0 similar 3, 4 similar 7 and 8 similar 14 postburn days (PBDs), respectively. And the incidences of hyperglycemia were 100%, 50% and 0% when the administration of rhGH started within 1, 2 and after 2 weeks respectively.

CONCLUSION

The systemic protein synthesis in severely burned patients could be accelerated by the use of rhGH. But early administration of rhGH in burned patients could affect blood sugar level obviously. And the optimal time to give rhGH is 2 weeks after burn injury.

A novel method for beat-to-beat detection of ventricular late potentials

A novel method for beat-to-beat detection of ventricular late potentials (VLP) from high-resolution electrocardiograms (ECGs) is presented. ECG signals from the X lead are first filtered using a bandpass filter, and then a time-sequence adaptive filter, to improve its signal-to-noise ratio. Eight features are extracted using wavelet transform, from the VLP time-frequency distribution of the filtered ECG signals, and used as inputs of specially designed artificial neural network for VLP recognition. The artificial neural network was trained and tested using clinical data, respectively. The results show that the presented method can detect beat-to-beat-based VLP with sensitivity of 80% and specificity of 77%, and the detection accuracy is 78%.

Platelet-derived growth factor C (PDGF-C), a novel growth factor that binds to PDGF alpha and beta receptor

We have characterized platelet-derived growth factor (PDGF) C, a novel growth factor belonging to the PDGF family. PDGF-C is a multidomain protein with the N-terminal region homologous to the extracellular CUB domain of neuropilin-1, and the C-terminal region consists of a growth factor domain (GFD) with homology to vascular endothelial growth factor (25%) and PDGF A-chain (23%). A serum-sensitive cleavage site between the two domains allows release of the GFD from the CUB domain. Competition binding and immunoprecipitation studies on cells bearing both PDGF alpha and beta receptors reveal a high affinity binding of recombinant GFD (PDGF-CC) to PDGF receptor-alpha homodimers and PDGF receptor-alpha/beta heterodimers. PDGF-CC exhibits greater mitogenic potency than PDGF-AA and comparable or greater mitogenic activity than PDGF-AB and PDGF-BB on several mesenchymal cell types. Analysis of PDGF-CC in vivo in a diabetic mouse model of delayed wound healing showed that PDGF-CC significantly enhanced repair of a full-thickness skin excision. Together, these studies describe a third member of the PDGF family (PDGF-C) as a potent mitogen for cells of mesenchymal origin in in vitro and in vivo systems with a binding pattern similar to PDGF-AB.

Human CD34+ cell preparations contain over 100-fold greater NOD/SCID mouse engrafting capacity than do CD34- cell preparations

OBJECTIVE

The CD34 cell surface marker is used widely for stem/progenitor cell isolation. Since several recent studies reported that CD34(-) cells also have in vivo engrafting capacity, we quantitatively compared the engraftment potential of CD34(+) vs CD34(-) cell preparations from normal human placental/umbilical cord blood (CB), bone marrow (BM), and mobilized peripheral blood (PBSC) specimens, using the nonobese diabetic/severe combined immunodeficient (NOD/SCID) mouse model.

METHODS

CD34(+) and CD34(-) cell preparations were purified by four different approaches in 14 individual experiments involving 293 transplanted NOD/SCID mice. In most experiments, CD34(+) cells were depleted twice (CD34(=)) in order to obtain efficient depletion of CD34(+) cells from the CD34(-) cell preparations.

RESULTS

Dose-dependent levels of human hematopoietic cells were observed after transplantation of CD34(+) cell preparations. To rigorously assess the complementary CD34(-) cell preparations, cell doses 10- to 1000-fold higher than the minimum dose of the CD34(+) cell preparations necessary for engraftment were transplanted. Nevertheless, of 125 NOD/SCID mice transplanted with CD34(-) cell preparations purified from the same starting cells, only six mice had detectable human hematopoiesis, by flow cytometric or PCR assay.

CONCLUSIONS

CD34(-) cells provide only a minor contribution to hematopoietic engraftment in this in vivo model system, as compared to CD34(+) cells from the same samples of noncultured human cells. Hematopoiesis derived from actual CD34(-) cells is difficult to distinguish from that due to CD34(+) cells potentially contaminating the preparations.

A study on the prevention and treatment of myopia with nacre on chicks

The contents of mineral elements and amino acids in the hydrolysate of the traditional Chinese mineral medicine nacre have been determined. It has long since been proved by the practice of doctors of traditional Chinese medicine that pearl can be used to treat eye diseases. Based on such an understanding, a study is made of the influence of the said medicine on the incidence of myopia. First a form-sense-deprived model (FDM) for chicks is developed and the effect of the said medicine on the elongation of axis oculi is determined with an Abbe's comparator and an A-mode ultrasound instrument. The activity of superoxide dismutase (SOD), nitric oxide synthetase (NOS), and the content of nitric oxide (NO) in the retino-pigmental epithelium choroid homogenate are also analysed. The role of the said traditional Chinese mineral medicine in preventing and treating myopia is explained with respect to the above findings. The results obtained will provide a basis for using nacre, a traditional Chinese mineral medicine, to prevent and treat myopia.

Novel short-acting A2A adenosine receptor agonists for coronary vasodilation: inverse relationship between affinity and duration of action of A2A agonists

Several potent and selective A2A adenosine receptor agonists are currently available. These compounds have a high affinity for the A2A receptor and a long duration of action. However, in situations where a short duration of action is desired, currently available A2A receptor agonists are less than ideal. From a series of recently synthesized A2A receptor agonists, two agonists (CVT-3146 and CVT-3033) with low affinity were selected for further characterization as selective and short-acting coronary vasodilators. Both compounds were selective for the A2A adenosine receptor (AdoR) versus the A1, A2B, and A3AdoR in binding and functional studies. CVT-3146 and CVT-3033 appeared to be weak partial agonists to cause cAMP accumulation in PC12 cells, but were full and potent agonists to cause coronary vasodilation, a response that has a very large A2A receptor reserve. However, the durations of action of CVT-3146 and CVT-3033 were remarkably shorter than those of the high-affinity agonists CGS21680 or WRC0470, presumably due to the relative lower affinity of CVT-3146 and CVT-3033 for the A2A receptor. Indeed, an inverse relationship was found between the affinity of the various agonists for the A2A receptor and the duration of their actions. These data indicate that low-affinity agonists can produce a response that is of equivalent magnitude but more rapid in termination than that caused by a high-affinity agonist. Hence, the low-affinity A2A agonists CVT-3146 and CVT-3033 may prove to be superior to currently available high-affinity agonists as coronary vasodilators during myocardial imaging with radionuclide agents.

[Surgical treatment of congenital nuclear cataract]

OBJECTIVE

To study the characteristics of congenital nuclear cataract and evaluate the therapeutic effects of extracapsular cataract extraction (ECCE) with or without intraocular lens (IOL) implantation in different age groups.

METHOD

ECCE with or without IOL implantation was performed on 76 eyes of 38 cases with congenital nuclear cataract in different age groups. Under operative microscope, the characteristics of the opacity of the posterior capsule were described. The visual acuity and possible complications were followed up for a mean period of 6 months.

RESULTS

The opacity of the posterior capsule was progressively developing, its diameter was similar to that of the opaque nucleus. The difference of the post-operative corrected visual acuity in different age groups was significant (chi(2) = 27.84, P < 0.005). The rates of the secondary cataract were negatively correlated to the age groups (r = -0.969 2, P < 0.05). In 2 eyes, slight iris capture occurred in 3 - 12 year group.

CONCLUSIONS

Congenital nuclear cataract can combine with posterior capsular cataract. The etiology remains to be studied. The therapeutic effects of the congenital nuclear cataract mainly depend on the time of operation. The early treatment of post-operative complications in children is of primary importance.

Uncertainty in sample mass for small numbers of particles from granular materials

The standard deviation of sample mass was quantitatively related to the number of particles in the sample, individual particle masses and the fractions of the numbers of different types of particles in the mixture. The theory was verified by sampling of cereal grain mixtures with a spinning riffler and Monte Carlo computer simulation. The theory is applicable to random sampling of well-mixed populations containing two or more types of particles.

Uncertainty in analyte mass for samples containing small numbers of particles

A sampling equation was derived that relates the standard deviation in analyte mass to the number of particles in the sample, the fractions of the different types of particles in the mixture and the masses and analyte concentrations of the individual particles. The equation, which is applicable to samples containing any number of particles, was verified by sampling and analysis of two cereal grain mixtures for manganese, potassium, chlorine and magnesium, and by Monte Carlo computer simulation. Comparison of the sampling precision of analyte mass with the analytical measurement precision was also studied, and it was shown that use of the equation allows the calculation of the minimum number of particles required to hold the sampling relative standard deviation to that of the analytical measurement.