Effects of temperature and salinity on nitrogenous excretion by Litopenaeus vannamei juveniles

Excretion rates of ammonia-N, nitrite-N, nitrate-N, and dissolved organic nitrogen (DON) for juvenile Litopenaeus vannamei (3.85+/-0.83 g) were quantified in response to nine different combinations of temperature (24, 28, and 32 degrees C) and salinity (10, 25, and 40 ppt) under laboratory conditions. Results indicated that L. vannamei is ammonotelic, with ammonia-N accounting for 61.9-84.3% of total nitrogen (TN) excretion. There were significant effects of temperature and salinity, but no significant interaction between them, on ammonia-N excretion rate (R(AN)). R(AN) increased with increasing temperature, over the interval 24-32 degrees C. R(AN) was lower at 25 ppt than at 10 and 40 ppt, at all temperatures. DON excretion rate (R(DON)) was not significantly influenced by either temperature or salinity; the overall mean R(DON) was about 5.24 µg-N g -1 h -1. However, the percentages of DON in TN (P(DON)) varied from 15.4 to 36.4% under the various temperature-salinity combinations. P(DON) at 28 and 32 degrees C was significantly lower than at 24 degrees C, and P(DON) at 10 ppt was significantly lower than at 25 and 40 ppt. Only very small amounts of nitrogen were excreted by L. vannamei as nitrite-N and nitrate-N.

Repressor activity of Headless/Tcf3 is essential for vertebrate head formation

The vertebrate organizer can induce a complete body axis when transplanted to the ventral side of a host embryo by virtue of its distinct head and trunk inducing properties. Wingless/Wnt antagonists secreted by the organizer have been identified as head inducers. Their ectopic expression can promote head formation, whereas ectopic activation of Wnt signalling during early gastrulation blocks head formation. These observations suggest that the ability of head inducers to inhibit Wnt signalling during formation of anterior structures is what distinguishes them from trunk inducers that permit the operation of posteriorizing Wnt signals. Here we describe the zebrafish headless (hdl) mutant and show that its severe head defects are due to a mutation in T-cell factor-3 (Tcf3), a member of the Tcf/Lef family. Loss of Tcf3 function in the hdl mutant reveals that hdl represses Wnt target genes. We provide genetic evidence that a component of the Wnt signalling pathway is essential in vertebrate head formation and patterning.

[Rainfall interception capacity of forest canopy between two different stands]

Based on the observation data, the rainfall interception capacity of the canopy in plantation and natural forest stands and its relation to rainfall were examined using the method of taking maximum under the same rainfall. The results showed that the rainfall interception capacity of plantation forest increased rapidly with the increase of rainfall, because of its even distribution of branches and leaves, which was higher under low rainfall less than 30 mm, and the saturation interception capacity was easily reached, depending on the quantity of branches and leaves in the canopy. Although the interception capacity of natural forest was relatively weak under low rainfall less than 30 mm, compared with plantation forest, it was much stronger under heavy rainfall more than 30 mm. The saturation interception of natural forest was larger than that of plantation forest.

Plasma carbon monoxide levels in term newborn infants with sepsis

Carbon monoxide (CO) has been implicated as a new endogenously produced mediator similar to nitric oxide (NO). CO was measured in plasma samples from 7 term newborn infants with sepsis and from 30 healthy neonates. Plasma CO levels were significantly higher in the group with sepsis at the time of admission to the neonatal intensive care unit than in the healthy controls (p < 0.05). Moreover, the elevated plasma CO levels were significantly related to increased NO production, as indicated by plasma nitrite/nitrate levels (p < 0.05). The present study suggests that, in addition to NO, CO might be another important mediator taking part in the pathogenesis of neonatal sepsis.

[Clinical and experimental study on treatment of infantile autumn diarrhea by retention enema with Qilian liquid]

OBJECTIVE

To find out the effective treatment for infantile autumn diarrhea (IAD).

METHODS

Retention enema with Qilian Liquid (QLL) was applied to the patients of IAD with positive antigen of rotavirus in stool, and the clinical effect in the treated group was compared with that in the control group in aspects of negative conversion rate of rotavirus and change of immunoglobulin. Animal experimental study was also conducted.

RESULTS

The disappearance time of principal symptoms, negative conversion rate of rotavirus and serum levels of IgA and IgG in the treated group were significantly higher than those in the control group (P < 0.01, P < 0.05). Experimental study showed that QLL not only has the the anti-viral effects to stop diarrhea, but also has effects in enhancing immune function and protecting intestinal mucous membrane.

CONCLUSION

Retention enema with QLL is an effective therapy for the treatment of IAD.

Chronic brain oxidation in a glutathione peroxidase knockout mouse model results in increased resistance to induced epileptic seizures

Systemic administration of kainic acid (KA) to rodents results in limbic seizures and subsequent neurodegeneration similar to that observed in certain types of human epilepsy, and it is a commonly used animal model for this disease. Oxidative stress has been suggested to play a role in the neuronal injury associated with KA administration. Based on this observation, chronic treatment with antioxidants has been proposed as a possible protective therapy against neuronal damage associated with epileptic seizures. Here we demonstrate by histochemical, electrophysiological, and biochemical means that knockout mice with decreased activity of the protective antioxidant enzyme glutathione peroxidase, which display elevated basal brain oxidative stress levels, are resistant to KA-induced seizure activity and neurodegeneration. This appears to be a result of decreased NMDA receptor function due to oxidation of its NR1 subunit. This suggests that the chronic use of antioxidants as antiepileptic agents to modulate NMDA-dependent seizure-induced neurodegeneration may be detrimental rather than protective and calls into question their use as a therapeutic agent in the treatment of epilepsy.

Neural responses in the inferior colliculus to binaural masking level differences created by inverting the noise in one ear

We have measured the responses of inferior colliculus neurons in the anesthetized guinea pig to signals which in human psychophysical experiments reveal a release of masking as a result of binaural processing (the binaural masking level difference: BMLD). More specifically we have used diotic tones at 500 Hz (So) masked by noise that is either identical at the two ears (No) or inverted in one ear (Npi). This combination of signals and noise maskers produces a prominent masking release in humans such that the So signal is about 6-12 dB more detectable in the presence of the Npi noise than the No noise. Low-frequency inferior colliculus neurons are sensitive to the interaural delay of the masking noise and generally respond most to the components nearest their best frequency. Since most inferior colliculus neurons have peaks in their delay functions close to zero interaural time delay this means that while No noise is effective in driving the unit, Npi noise is much less effective. As the level of an So tone was progressively increased in the presence of No and Npi noises, the first response could be either an increase or a decrease in the activity due to the noise. However, because Npi generated little or no activity itself, the predominant response to the So tone was an increase in discharge in this condition. Masked thresholds were defined as the point at which the standard separation D (related to the d' of signal detection theory) = 1 in either direction. BMLDs were measured in single neurons and in the majority of units were in a direction consistent with the psychophysical observations irrespective of the direction of the discharge rate change that occurred at threshold. The lowest masked thresholds always occurred at or near the signal frequency of 500 Hz. An average value of the single unit BMLD around 500 Hz was 3.6 dB (NoSo vs. NpiSo) compared with 6.6 dB for the NoSo versus NoSpi BMLD we had previously reported. This lower magnitude is consistent with the hierarchy of human psychophysical BMLDs.

Preclinical trials of human erythrocyte superoxide dismutase injection

OBJECTIVE

To assess the quality of human erythrocyte superoxide dismutase (SOD) injection reaching the official standard for its clinical uses.

METHODS

Human erythrocyte SOD injection prepared by McCord-Fridovich's method without column chromatography but with some modifications was used in preclinical trials, to observe the general pharmacology and pharmacodynamics of the product.

RESULTS

The quality of human erythrocyte SOD injection conformed to the official standard of a biological product, which was found to be non-toxic and did not have any effects on the central and autonomic nervous systems as well as cardiovascular and respiratory systems. The efficacy of anti-inflammation and promotion of immuno-regulation especially on carrageenan and adjuvant-induced polyarthritis were shown in animals.

CONCLUSION

Human erythrocyte SOD injection is appropriate for prophylactic and therapeutic uses in clinical trials.

Evidence for the existence of insect defensin-like peptide in scorpion venom

Insect defensin refers to a group of antibacterial peptides derived from a variety of insect species as well as from scorpion and possessing a three-dimensional structure highly similar to that of scorpion toxins. A full-length cDNA encoding an insect defensin-like peptide was isolated from the venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch. The precursor, the overall organization of which is similar to that of insect defensins, consists of 61 amino acid residues with a putative signal peptide of 15 residues, a propeptide of 7 residues, and a mature peptide of 39 residues (named BmTXKS2). The positions of six cysteines and a conserved glycine in mature BmTXKS2 are the same as those in LqDef, the first defensin found in scorpions, which suggests these peptides should present a similar cysteine-stabilized alphabetamotif. Phylogenetic analysis further shows that the structure of BmTXKS2 is closer to that of ancient defensins (e.g., LqDef and AaDef, two insect defensins present in the scorpion hemolymph) than to scorpion toxins.

[Effects of retionoic acid and GM-CSF on apoptosis of HL-60 cell induced by mild heat]

The effects of several factors on the apoptosis of HL-60 cells, a human acute myeloid leukemia cell line, were investigated. The apoptosis model was established with mild heat. Typical changes of cell morphology and characteristic DNA ladder pattern were found. The effect of apoptosis induced by mild heat was enhanced, when HL-60 cells were pretreated with the retinoic acid. By contraries, that of apoptosis was displayed with the slight inhibition while HL-60 cells were pretreated with rhGM-CSF. We also observed the alterations of mRNA expressions of c-myc by the dot hybridization. The results indicate that both the mild heat and the combination of mild heat and retinoic acid obviously reduce the mRNA expression of c-myc compared to the control group.

[Ecological process of vegetation restoration in Caragana mirophylla sand-fixing area]

The occurrence and development of artificial vegetation after mobile sandy dunes being fixed by adopting straw check combining with seeding Caragana microphylla were studied. Especially the process of species invasion and the changes of community structure in 35 years were analyzed in detail. The results showed that the species richness of artificial community of C. microphylla increased, from 5 species (in 2 years) to 23 species in 35 years. In the structure concerning plant lifeform, therophytes were in dominant position, while the ratio of therophytes to all plant species had a tendency of decrease. The rates of species number and the quantity of hemicryptophytes and geocryptophytes increased gradually. Species diversity and community evenness indexes increased and ecological dominance index decreased gradually. The similarity index of the artificial plant community to natural one increased with age. The changes of physical and chemical property of soil were also discussed.

Cloning and sequencing of partial genes of hepatitis C virus genome in patients with acute hepatitis C

OBJECTIVE

To explore the etiological role of HCV in patients with acute hepatitis.

METHODS

The prevalence of HCV infection in 89 patients with acute hepatitis was investigated by analysis of HCV RNA and HCV second generation antibody. HCV RNAs extracted from the sera of 5 patients with NANB acute hepatitis, which were positive for HCV RNA, were converted to cDNA by reverse transcription with random primer and genotyping by PCR with type-specific primers. The partial genes of HCV genome were amplified. The PCR products were expressed in E. coli with p-GEM-T vector, and their nucleotide sequences were determined by dideoxynucleotide chain-termination method.

RESULTS

The incidence of hepatitis virus infection was 47. 2% in HAV, 28.1% in HBV and 15.7% in HCV, respectively. The incidence of HAV and HBV coinfection was 14.6% and the rate of non-A, non-B and non-C hepatitis was 9% in all patients. The genotype of HCV-RNA positive patients was 85.8% in HCV-II, 7.1% in HCV-III and 7. 1% in combining HCV-II/III, respectively. The partial sequence of HCV genome in 5 patients with non-A and non-B acute hepatitis was amplified and the fragment was 424 bp in accordance with original design. The homology of the sequences was 98.1%-99.5% in nucleotide acid and 97.6%-99.2% in amino acid among five isolates. The average homology was 91.9% or 94.3%-95.6% for nucleotide sequences between HCV-I or HCV-II and the 5 isolates, and 92.3%-95.8% for amino acid sequences between the 5 isolates and HCV-I or HCV-II, respectively.

CONCLUSION

HCV infection is one of the main hepatitis viruses in patients with acute hepatitis, in which the HCV-II genotype is dominant and should be paid attention to it.

[Effects of dibutyl phthalate on the proliferation and apoptosis of leukemic cells]

This study was designed to investigate the effects of dibutyl phthalate (DBP) on the proliferation and apoptosis of leukemic cells. The results showed that DBP suppressed the proliferation of HL-60 and K562 leukemic cells in a dose-dependent and time-dependent manner. Inducing HL-60 and K562 leukemic cells to die via apoptosis were confirmed by that the percentage of the apoptotic cells in morphology and of the DNA fragmentation increased significantly and that typical ladders of apoptosis were shown by gel electrophoresis when HL-60 and K562 cells were exposed to the DBP. Also, K562 leukemic cells was less susceptible to the DBP than HL-60 cells. These results indicate that DBP can inhibit the proliferation of HL-60 and K562 leukemic cells and induced them to die via apoptosis.

[Culture of murine HPP-CFC in vitro using conditioned medium substitutefor recombinant growth factors]

OBJECTS

To study the clonal growth on single layer, agar of high proliferative potential colony-forming cells (HPP-CFC) of bone marrow obtained from both normal mice (NBM) and mice treated 2 days earlier with 5-fluorouracil (FU,BM) using conditioned media.

MATERIAL AND METHODS

Using liquid cell culture to harvert WEHI2-CM and L929-CM as the substitutes for IL-3 and M-CSF respectively; using semi-solid culture to assay HP-CFCin vitro.

RESULTS

(1) the combination of WEHI3-CM and L929-CM produced HPP-CFC in vitro, and the addition of rhIL-1 alpha, rhIL-6 and rmGM-CSF further enhanced HPP-CFC was enriched in the FU2 BM. Morphological investigation showed that the HPP-CFC colony was large and compact, great than 0.5mm in diameter and contained more than 50,000 cells, most of which were macrophage like cells. The hydroxyurea suicide rate for HPP-CFC was less than 10%.

CONCLUSION

The results suggested that (1) WEHI3-CM and L929-CM can be used as the substitutes of IL-3 and M-CSF to stimulate the formation of HPP-CFC; (2) FU can enrich HPP-CFC of the mice.

Defective cleavage of membrane bound TGFalpha leads to enhanced activation of the EGF receptor in malignant cells

Transforming growth factor alpha (TGFalpha) is widely expressed in malignant as well as normal cells and is involved in regulating cell growth and differentiation. Although processing of TGFalpha has been extensively studied in normal cells, there is little information regarding TGFalpha cleavage in malignant cells. Therefore, we compared the processing of TGFalpha in two human colon carcinoma cell lines. We found that there was a defective cleavage pattern for the TGFalpha precursor resulting in retention of partially processed TGFalpha on the cell surface of both the HCT116a2alphaS3 and CBS4alphaS2 cell lines. This raised the possibility that signaling from the resulting defective cleavage species could differ from that of soluble TGFalpha. The membrane-associated TGFalpha induced higher phosphorylation of EGFR on the cell surface of adjacent cells than equivalent levels of mature TGFalpha. The interaction of membrane bound TGFalpha precursor with the EGFR caused a slower internalization of activated EGFR relative to the internalization of the soluble TGFalpha/EGFR complexes. In addition, the tethered TGFalpha was resistant to the ability of protein-tyrosine phosphatases (PTPs) to reduce EGFR tyrosine phosphorylation, also contributing to higher activation of EGFR. The enhanced activation of EGFR by the tethered form of TGFalpha was reflected by higher activation of Grb2, SHC and Erk downstream mediators of EGF receptor signaling. The higher activation of EGFR by membrane tethered TGFalpha indicates that defective TGFalpha processing provides a mechanism whereby malignant cells can obtain a growth advantage over normal cells.

Abnormal expression of hepatoma specific gamma-glutamyl transferase and alteration of gamma-glutamyl transferase gene methylation status in patients with hepatocellular carcinoma

BACKGROUND

Hepatoma specific gamma-glutamyl transferase (HS-GGT) bands were expressed in the development of hepatocellular carcinoma (HCC) and were associated with a high incidence of HCC diagnosis. The objectives of this study were to determine the levels of HS-GGT quantitatively in the sera of patients with different liver diseases. The methylational status of GGT gene CCGG sites was analyzed in hepatoma tissues.

METHODS

The HS-GGT concentrations were quantitatively analyzed in the sera of 156 HCC patients and others with liver diseases or extrahepatic tumors. In 20 hepatoma tissues, the GGT enzyme proteins were purified, the activities of GGTs of different molecular form were examined, total RNAs were extracted and amplified by using a nested polymerase chain reaction (PCR) assay, and the methylational status of CCGG site (M3) in the 5'-noncoding region of GGT genes was investigated with the restriction enzyme Hpa II.

RESULTS

Total GGT activities in patients with liver diseases and extrahepatic tumors were abnormally increased. The levels of serum HS-GGT were significantly elevated (P < 0.001) in the HCC group; the incidence of HS-GGT over 5.5 IU/L was 86% in HCC patients and less than 3% in patients with other diseases. From liver cancer to distal noncancerous tissues, an increasing tendency (P < 0.05) of total RNA concentrations was found; the frequencies of amplified fragment and hypomethylated M3 site of GGT genes were 100% and 75% in HCC, 85% and 55% in paracancerous tissues, and 75% and 50% in noncancerous tissues, respectively. An inverse correlation was found between methylational degrees of GGT genes and expression levels of GGT.

CONCLUSIONS

The abnormal alteration of serum HS-GGT level is a sensitive tumor marker for HCC diagnosis or differentiation, and the overexpression of GGT in HCC may be related to the hypomethylational status of CCGG sites of GGT genes.

Abnormal expression of hepatoma specific gamma-glutamyl transferase and alteration of gamma-glutamyl transferase gene methylation status in patients with hepatocellular carcinoma

BACKGROUND

Hepatoma specific gamma-glutamyl transferase (HS-GGT) bands were expressed in the development of hepatocellular carcinoma (HCC) and were associated with a high incidence of HCC diagnosis. The objectives of this study were to determine the levels of HS-GGT quantitatively in the sera of patients with different liver diseases. The methylational status of GGT gene CCGG sites was analyzed in hepatoma tissues.

METHODS

The HS-GGT concentrations were quantitatively analyzed in the sera of 156 HCC patients and others with liver diseases or extrahepatic tumors. In 20 hepatoma tissues, the GGT enzyme proteins were purified, the activities of GGTs of different molecular form were examined, total RNAs were extracted and amplified by using a nested polymerase chain reaction (PCR) assay, and the methylational status of CCGG site (M3) in the 5'-noncoding region of GGT genes was investigated with the restriction enzyme Hpa II.

RESULTS

Total GGT activities in patients with liver diseases and extrahepatic tumors were abnormally increased. The levels of serum HS-GGT were significantly elevated (P < 0.001) in the HCC group; the incidence of HS-GGT over 5.5 IU/L was 86% in HCC patients and less than 3% in patients with other diseases. From liver cancer to distal noncancerous tissues, an increasing tendency (P < 0.05) of total RNA concentrations was found; the frequencies of amplified fragment and hypomethylated M3 site of GGT genes were 100% and 75% in HCC, 85% and 55% in paracancerous tissues, and 75% and 50% in noncancerous tissues, respectively. An inverse correlation was found between methylational degrees of GGT genes and expression levels of GGT.

CONCLUSIONS

The abnormal alteration of serum HS-GGT level is a sensitive tumor marker for HCC diagnosis or differentiation, and the overexpression of GGT in HCC may be related to the hypomethylational status of CCGG sites of GGT genes.

Abnormal expression of hepatoma specific gamma-glutamyl transferase and alteration of gamma-glutamyl transferase gene methylation status in patients with hepatocellular carcinoma

BACKGROUND

Hepatoma specific gamma-glutamyl transferase (HS-GGT) bands were expressed in the development of hepatocellular carcinoma (HCC) and were associated with a high incidence of HCC diagnosis. The objectives of this study were to determine the levels of HS-GGT quantitatively in the sera of patients with different liver diseases. The methylational status of GGT gene CCGG sites was analyzed in hepatoma tissues.

METHODS

The HS-GGT concentrations were quantitatively analyzed in the sera of 156 HCC patients and others with liver diseases or extrahepatic tumors. In 20 hepatoma tissues, the GGT enzyme proteins were purified, the activities of GGTs of different molecular form were examined, total RNAs were extracted and amplified by using a nested polymerase chain reaction (PCR) assay, and the methylational status of CCGG site (M3) in the 5'-noncoding region of GGT genes was investigated with the restriction enzyme Hpa II.

RESULTS

Total GGT activities in patients with liver diseases and extrahepatic tumors were abnormally increased. The levels of serum HS-GGT were significantly elevated (P < 0.001) in the HCC group; the incidence of HS-GGT over 5.5 IU/L was 86% in HCC patients and less than 3% in patients with other diseases. From liver cancer to distal noncancerous tissues, an increasing tendency (P < 0.05) of total RNA concentrations was found; the frequencies of amplified fragment and hypomethylated M3 site of GGT genes were 100% and 75% in HCC, 85% and 55% in paracancerous tissues, and 75% and 50% in noncancerous tissues, respectively. An inverse correlation was found between methylational degrees of GGT genes and expression levels of GGT.

CONCLUSIONS

The abnormal alteration of serum HS-GGT level is a sensitive tumor marker for HCC diagnosis or differentiation, and the overexpression of GGT in HCC may be related to the hypomethylational status of CCGG sites of GGT genes.

Responses of neurons in the inferior colliculus to dynamic interaural phase cues: evidence for a mechanism of binaural adaptation

Responses to sound stimuli that humans perceive as moving were obtained for 89 neurons in the inferior colliculus (IC) of urethan-anesthetized guinea pigs. Triangular and sinusoidal interaural phase modulation (IPM), which produced dynamically varying interaural phase disparities (IPDs), was used to present stimuli with different depths, directions, centers, and rates of apparent motion. Many neurons appeared sensitive to dynamic IPDs, with responses at any given IPD depending strongly on the IPDs the stimulus had just passed through. However, it was the temporal pattern of the response, rather than the motion cues in the IPM, that determined sensitivity to features such as motion depth, direction, and center locus. IPM restricted only to the center of the IPD responsive area, evoked lower discharge rates than when the stimulus either moved through the IPD responsive area from outside, or up and down its flanks. When the stimulus was moved through the response area first in one direction and then back in the other, and the same IPDs evoked different responses, the response to the motion away from the center of the IPD responsive area was always lower than the response to the motion toward the center. When the IPD was closer at which the direction of motion reversed was to the center, the response to the following motion was lower. In no case did we find any evidence for neurons that under all conditions preferred one direction of motion to the other. We conclude that responses of IC neurons to IPM stimuli depend not on the history of stimulation, per se, but on the history of their response to stimulation, irrespective of the specific motion cues that evoke those responses. These data are consistent with the involvement of an adaptation mechanism that resides at or above the level of binaural integration. We conclude that our data provide no evidence for specialized motion detection involving dynamic IPD cues in the auditory midbrain of the mammal.

Abnormal expression of hepatoma specific gamma-glutamyl transferase and alteration of gamma-glutamyl transferase gene methylation status in patients with hepatocellular carcinoma

BACKGROUND

Hepatoma specific gamma-glutamyl transferase (HS-GGT) bands were expressed in the development of hepatocellular carcinoma (HCC) and were associated with a high incidence of HCC diagnosis. The objectives of this study were to determine the levels of HS-GGT quantitatively in the sera of patients with different liver diseases. The methylational status of GGT gene CCGG sites was analyzed in hepatoma tissues.

METHODS

The HS-GGT concentrations were quantitatively analyzed in the sera of 156 HCC patients and others with liver diseases or extrahepatic tumors. In 20 hepatoma tissues, the GGT enzyme proteins were purified, the activities of GGTs of different molecular form were examined, total RNAs were extracted and amplified by using a nested polymerase chain reaction (PCR) assay, and the methylational status of CCGG site (M3) in the 5'-noncoding region of GGT genes was investigated with the restriction enzyme Hpa II.

RESULTS

Total GGT activities in patients with liver diseases and extrahepatic tumors were abnormally increased. The levels of serum HS-GGT were significantly elevated (P < 0.001) in the HCC group; the incidence of HS-GGT over 5.5 IU/L was 86% in HCC patients and less than 3% in patients with other diseases. From liver cancer to distal noncancerous tissues, an increasing tendency (P < 0.05) of total RNA concentrations was found; the frequencies of amplified fragment and hypomethylated M3 site of GGT genes were 100% and 75% in HCC, 85% and 55% in paracancerous tissues, and 75% and 50% in noncancerous tissues, respectively. An inverse correlation was found between methylational degrees of GGT genes and expression levels of GGT.

CONCLUSIONS

The abnormal alteration of serum HS-GGT level is a sensitive tumor marker for HCC diagnosis or differentiation, and the overexpression of GGT in HCC may be related to the hypomethylational status of CCGG sites of GGT genes.

MAPK pathways activate and phosphorylate the osteoblast-specific transcription factor, Cbfa1

The bone-specific transcription factor, Cbfa1, regulates expression of the osteocalcin (OCN) gene and is essential for bone formation. However, little is known about the mechanisms regulating Cbfa1 activity. This work examines the role of the MAPK pathway in regulating Cbfa1-dependent transcription. Stimulation of MAPK by transfecting a constitutively active form of MEK1, MEK(SP), into MC3T3-E1 preosteoblast cells increased endogenous OCN mRNA, while a dominant negative mutant, MEK(DN), was inhibitory. MEK(SP) also stimulated activity of a 147-base pair minimal OCN promoter, and this stimulation required an intact copy of OSE2, the DNA binding site for Cbfa1. Effects of MEK(SP) were specific to Cbfa1-positive osteoblast-like cells. A purified His-tagged Cbfa1 fusion protein was directly phosphorylated by activated recombinant MAPK in vitro. Furthermore, (32)P metabolic labeling studies demonstrated that MEK(SP) clearly enhanced phosphorylation of Cbfa1 in intact cells, while MEK(DN) decreased phosphorylation. The specific MEK1/MEK2 inhibitor, PD98059, inhibited extracellular matrix-dependent up-regulation of the OCN promoter, indicating that the MAPK pathway and, presumably, Cbfa1 phosphorylation are also required for responsiveness of osteoblasts to extracellular matrix signals. This study is the first demonstration that Cbfa1 is controlled by MAPKs and suggests that this pathway has an important role in the control of osteoblast-specific gene expression.

[Experimental study on value of carcino-embryonic gama-glutamyl transferase isoenzymes for monitoring carcinogenesis of hepatocytes]

OBJECTIVE

To explore the value of gama-glutamyl transferase (GGT) abnormal expression in monitoring carcinogenesis of hepatocytes.

METHODS

The kinetic alterations of rat (SD) liver pathology, enzymatic histochemistry, total RNA levels, different molecular form GGT and its isoenzymes were investigated on experimental hepatomas inducing with 0.05% 2-fluoenylacetamide (2-FAA).

RESULTS

The GGTs of livers were overexpressed during canceration, liver GGT specific activities (U/g) including soluble and membrane-combined GGT activities of each group in experiment rats were significantly higher (q=4.90, P<0.01) than those of control group. The total RNA concentration was highly positively correlated with liver GGT specific activities or serum GGT activities (r=0.90, r=0.79, P<0.01). The mixed isoenzyme patterns of control rats' and embryo rats' GGT were found in sera and livers of experimental rats, the carcino-embryonic GGT bands can be detected at early stages of rat hepatocyte canceration.

CONCLUSIONS

The present data suggest that GGT is a sensitive enzyme for carcinogenesis of hepatocytes, the analysis of carcino-embryonic GGT is a useful marker for early diagnosis of rat hepatoma.

[Relationship of bcl-2 gene expression with cell proliferation and apoptosis in human gliomas]

OBJECTIVE

To investigate the relationship of bcl-2 gene expression level in human gliomas with the malignant degree, cell proliferative activity and apoptosis of the tumors.

METHODS

The expression of bcl-2 mRNA, bcl-2 protein and proliferating cell antigen, and the apoptosis in sixty-nine human glioma specimens with different malignant grades were studied using in situ hybridization, in situ cell death detection (TUNEL method) and immunohistochemistry.

RESULTS

Of the 69 gliomas, 64 (92.8%) and 60 (87.0%) expressed bcl-2 mRNA and bcl-2 protein, respectively. The expression levels of bcl-2 mRNA and bcl-2 protein were correlated positively with each other (r(s) = 0.999, P < 0.01). The expression levels of bcl-2 mRNA and bcl-2 protein were both higher in WHO grade IV gliomas than in grade III gliomas, and the expression was lowest in grade I-II gliomas (P < 0.02 approximately 0.001). With the increase in the expression of bcl-2 protein, the cell proliferating activity increased and apoptosis decreased in the tumor cells. There was significant difference of cell proliferation and apoptosis between + + + group and + + group of bcl-2 protein expression (P < 0.05) as well as between both the former groups, and the negative and + group (P < 0.01) respectively.

CONCLUSIONS

Over-expression of bcl-2 gene inhibits apoptosis of glioma cells, and the inhibitory intensity increases with the ascending of bcl-2 gene expression level in glioma cells. Both the decrease in apoptosis caused by bcl-2 gene over-expression and the excessive cell proliferation promoted by other gene abnormalities may result in unlimited cell accumulation, which may play an important role in the development and malignant progression of gliomas.

The value of in-phase and opposed-phase T1-weighted breath-hold FLASH sequences for hepatic imaging

The value of the combined in-phase (IP) and opposed-phase (OP) T1-weighted (T1-W) breath-hold FLASH sequences for hepatic imaging, especially for fat content, was evaluated. Non-contrast-enhanced IP and OP T1-W GRE breath-hold images were obtained in 76 patients refereed for abdominal MRI at 1.5T. 76 patients were divided into three groups for analysis: (1) liver without mass (n = 8); (2) liver with hepatoma (n = 34); (3) liver with haemangioma or cyst (n = 34). Liver/spleen and liver/lesion signal-to-noise (SNR) and contrast-to-noise ratio (CNR) were assessed for lesion detection. Images between IP and OP sequences were compared quantitatively. The results showed that there was not statistically significant difference in liver/spleen and liver/lesion SNR between IP and OP sequences. In the patients with fatty infiltration, the OP sequences yielded substantially lower values for liver/spleen and liver/lesion SNR than those of the IP sequences. Furthermore, OP imaging showed fatty infiltration in 14 cases and demonstrated hyperintense peritumor rim in 4 cases. In 14 cases of fatty infiltration, many lesions were identified using IP images. The use of IP and OP GRE sequences provides complementary diagnostic information for hepatic lesions and fat content. Focal hepatic lesions may be obscured in the setting of fatty infiltration if only OP sequences are employed. A complete assessment of the liver with MR should include both IP and OP imaging.

Mice deficient in cellular glutathione peroxidase show increased vulnerability to malonate, 3-nitropropionic acid, and 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine

Glutathione peroxidase (GSHPx) is a critical intracellular enzyme involved in detoxification of hydrogen peroxide (H(2)O(2)) to water. In the present study we examined the susceptibility of mice with a disruption of the glutathione peroxidase gene to the neurotoxic effects of malonate, 3-nitropropionic acid (3-NP), and 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine (MPTP). Glutathione peroxidase knock-out mice showed no evidence of neuropathological or behavioral abnormalities at 2-3 months of age. Intrastriatal injections of malonate resulted in a significant twofold increase in lesion volume in homozygote GSHPx knock-out mice as compared to both heterozygote GSHPx knock-out and wild-type control mice. Malonate-induced increases in conversion of salicylate to 2,3- and 2, 5-dihydroxybenzoic acid, an index of hydroxyl radical generation, were greater in homozygote GSHPx knock-out mice as compared with both heterozygote GSHPx knock-out and wild-type control mice. Administration of MPTP resulted in significantly greater depletions of dopamine, 3,4-dihydroxybenzoic acid, and homovanillic acid in GSHPx knock-out mice than those seen in wild-type control mice. Striatal 3-nitrotyrosine (3-NT) concentrations after MPTP were significantly increased in GSHPx knock-out mice as compared with wild-type control mice. Systemic 3-NP administration resulted in significantly greater striatal damage and increases in 3-NT in GSHPx knock-out mice as compared to wild-type control mice. The present results indicate that a knock-out of GSHPx may be adequately compensated under nonstressed conditions, but that after administration of mitochondrial toxins GSHPx plays an important role in detoxifying increases in oxygen radicals.

[Best minimization to locate the brain sources of magnetic waves]

Locating the sources of brain magnetic fields is a basic question in magnetoencephalography (MEG). This question belongs to the indeterminate problem, that is, infinite solutions can be obtained from the equations of the measured small magnetic fields on the detector. Therefore a model of mathematics is needed to give more information. The major models of mathematics are the search method with many dipoles and the Lp minimum norm method. For the first model, if a global search is used, too much calculation time will be spent; if the gradient search is used, the searches usually converge to a local minimun. So other methods are introduced to find out the initial values, and then the gradient search can be used. For the second model, the depth of the brain sources will dependend on the choice of the weight functions which have several different types, and we do not know in advance which type is correct, so that it is difficult to have a good estimation of the depth of the brain sources. To overcome the difficulties, we use the method with three object functions which are the minimum Lp norm, the deviation between the calculated magnetic fields and the measured magnetic fields, and the number of the sources. This method is similar to the minimum norm method, a weight function is also introduced. But this weight function contains many reference variables which have to be determined through the minimization with three object functions. By choosing suitable weight function and its reference variables, the correct estimation of the depth of the brain sources can be achieved.

[Perspectives of effect on new electrode technology with implantable motor prostheses for stimulating peripheral nerves]

This paper explores approaches to electrode technology and stimulating techniques that selectively activate specific portions of a peripheral nerve trunk with much less implanted hardware than is required with present motor prosthesis systems. The first section reviews the vulnerability of nerves to both mechanical and electrical factors and suggests ideas on how these findings might be utilized in future electrodes. The second section presents results on longitudinally oriented intrafascicular electrodes for nerve stimulation recording. The third section reviews results on longitudinal intrafascicular electrodes for nerve stimulation and recording.

[Analysis of 16 cases with aggressive fungal maxillary sinusitis]

OBJECTIVE

To improve the diagnosis and treatment level of aggressive fungal maxillary sinusitis.

METHOD

16 cases were diagnosed with CT. Caldwell-Luc's surgery was done in 13 cases and Lima surgery in 3 cases. None of them were treated by antifungal agents.

RESULT

It showed osteolytic damage with bony defect which was different from expanded bony defect caused by benign tumor, but similar to malignant tumor. No recurrence occurred as followed from 6 months to 2 years.

CONCLUSION

Computed tomography is very important in its diagnosis. Early explorative operation is useful in making definite diagnosis.

Regulation of D(1) dopamine receptors with mutations of protein kinase phosphorylation sites: attenuation of the rate of agonist-induced desensitization

Investigations of D(1) receptor regulation have suggested a role for cAMP-dependent protein kinase (PKA) in agonist-induced desensitization and down-regulation of receptor expression. Given the presence of at least four possible consensus recognition sites for PKA on the D(1) receptor protein, a reasonable hypothesis is that some of these PKA-mediated effects are caused by phosphorylation of the receptor. As an initial test of this hypothesis, we used site-directed mutagenesis to create a mutant D(1) receptor with substitutions at each of its four potential PKA phosphorylation sites. The modified amino acids are as follows: Thr135 to Val, Ser229 to Ala, Thr268 to Val, and Ser380 to Ala. Characterization of the wild-type and mutant receptors stably expressed in C6 glioma cells suggests that the mutations have no effect on receptor expression, antagonist or agonist affinities, or on functional coupling with respect to cAMP generation. Similarly, dopamine preincubation of the stably transfected C6 cells expressing either the wild-type or mutated D(1) receptors results in an agonist-induced loss of ligand binding activity (down-regulation) in an identical fashion. In contrast, the time of onset of dopamine-induced desensitization is greatly attenuated in the quadruple mutant receptor. After 1 h of dopamine pretreatment, the wild-type receptor exhibits approximately 80% desensitization of the cAMP response, whereas the mutant receptor is desensitized by only approximately 20%. Further analyses of single mutated receptors, in which only one of the four putative phosphorylation sites is modified, reveals that Thr268 in the third cytoplasmic loop of the receptor protein is primarily responsible for regulating the desensitization kinetics. These results are consistent with the hypothesis that phosphorylation of the D(1) receptor on Thr268 is important for rapid agonist-induced homologous desensitization.

Molecular cloning and sequencing of two 'short chain' and two 'long chain' K(+) channel-blocking peptides from the Chinese scorpion Buthus martensii Karsch

Five full-length cDNAs encoding the precursors of two 'short chain' scorpion non-toxic peptides active on Ca(2+)-activated K(+) channels (BmP02 and BmP03) and two novel putative long chain K(+) channel-blocking peptides (named BmTXKbeta and BmTXKbeta2) were first isolated from the venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch (BmK). BmTXKbeta2 showed a high similarity with AaTXKbeta, while BmTXKbeta was completely different in the deduced primary structure from the long chain and short chain scorpion toxins already characterized. Thus, BmTXKbeta expands the scorpion long chain K(+) channel-blocking peptide family. Although little sequence similarity exists between the above two short and two long peptides, they are similar at the positions of six cysteines, suggesting that they should all share a similar scaffold composed of an alpha-helix and a three-stranded beta-sheet.

Existence and global attractivity of positive periodic solutions of periodic n-species Lotka-Volterra competition systems with several deviating arguments

In this paper, we study the existence and global attractivity of positive periodic solutions of periodic n-species Lotka-Volterra competition systems. By using the method of coincidence degree and Lyapunov functional, a set of easily verifiable sufficient conditions are derived for the existence of at least one strictly positive (componentwise) periodic solution of periodic n-species Lotka-Volterra competition systems with several deviating arguments and the existence of a unique globally asymptotically stable periodic solution with strictly positive components of periodic n-species Lotka-Volterra competition system with several delays. Some new results are obtained. As an application, we also examine some special cases of the system we considered, which have been studied extensively in the literature. Some known results are improved and generalized.

[The relationship between polymorphism of LMP2 and LMP7 genes and the phenotype of ankylosing spondylitis]

OBJECTIVE

To evaluate the relationship of the polymorphism of LMP2 and LMP7 genes and the phenotype of patients with ankylosing spondylitis(AS).

METHODS

One hundred and eighteen blood samples were collected from patients with AS and acute anterior uveitis(AAU). HLA-B(27) typing was performed and LMP2 and LMP7 amplified fragment length polymorphisms were determined after PCR and digestion with Cfo I restriction enzyme in the study.

RESULTS

There was a significantly increased LMP2 BB genotype frequency in patients with AS+AAU(86.9%) and AAU(87%), compared with controls(53.3%) and AS patients(63.1%)(P<0.05); the odds ratio(OR) relating LMP2 BB and AAU was 5.83, and the OR for AS+AAU was 3.71. No difference was found between adult AS and junior AS and between AS patients with and without extraspinal arthritis. No difference was found in LMP7 genotype.

CONCLUSION

The polymorphism of LMP2 gene is strongly associated with the development of AAU in AS patients and in uncomplicated AAU patients, but not with the age at onset and the type of joints affected.

Modification of an osteoconductive anorganic bovine bone mineral matrix with growth factors

BACKGROUND

Osteoconductive anorganic bovine bone mineral matrix material has been used clinically in bone regeneration procedures. Platelet-derived growth factor-BB (PDGF-BB) and insulin-like growth factor (IGF-I) are important anabolic growth factors for bone. It was the aim of these studies to 1) examine the interaction of this bone graft material with PDGF-BB and IGF-I and 2) determine if the combination of growth factors with the matrix could stimulate osteoblastic cell proliferation.

METHODS

Adsorption of PDGF-BB and IGF-I was done using 125I radio-labeled growth factors. The PDGF-BB or IGF-I was incubated with the anorganic bovine bone matrix, and the amount of adsorbed growth factor was measured. In the desorption studies, radiolabeled growth factors were adsorbed to the matrix material. The samples were incubated in buffer for various time periods, and the amount remaining on the matrix was measured to calculate the percentage of released growth factor. The biological activity was tested in an in vitro assay with primary culture neonatal rat osteoblastic cells. Porous bone matrix with known amounts of adsorbed PDGF-BB or IGF-I was produced. The osteoblastic cells were cultured on the bone mineral matrix, with and without adsorbed growth factor, and proliferation was assessed by 3H-thymidine incorporation.

RESULTS

Both PDGF-BB and IGF-I adsorbed to bone mineral matrix in a concentration-dependent fashion. The affinity of IGF-I for the material was 10-fold greater than PDGF-BB. In the experiments that measured the release of the initially adsorbed growth factors, approximately 50% of the PDGF-BB and 10% of the IGF-I were released after 10 days. PDGF-BB adsorbed to the matrix material significantly (P <0.05, ANOVA) enhanced the proliferation of cultured osteoblastic cells compared to the mineralized matrix alone. However, IGF-I adsorbed to the matrix material did not significantly enhance cell proliferation.

CONCLUSIONS

These results suggest that PDGF-BB can be adsorbed to the anorganic bovine bone mineral matrix and that this growth factor subsequently enhances the osteogenic properties of this bone graft material. IGF-I also adsorbed to the graft material; however, it was not readily released and it did not produce significant effects in the biologic assay. It appears that it may be clinically feasible to adsorb PDGF to anorganic bovine bone and that this combination of bone growth factor and mineral matrix has the potential for clinical applications.

[Observations on expression of c-fos and c-myc genes and activity of PDGFBB autocrine loop in 67 human gliomas]

OBJECTIVE

To investigate the variance of expression of c-fos and c-myc genes and the activity of platelet-derived growth factor (PDGF) BB autocrine loop in human gliomas as well as their relationship.

METHODS

In situ hybridization and immunohistochemistry were used to study 67 human glioma specimens of different grades.

RESULTS

The incidences, of positive expression for c-fos mRNA, c-fos protein, c-myc mRNA and c-myc protein were 100% (67/67), 100% (67/67), 85.1% (57/67) and 83.6% (56/67) respectively. There was significant positive correlation between the positive cell densities of c-fos mRNA (92.49 +/- 33.87) and c-fos protein (91.64 +/- 38.11), and of c-myc mRNA (72.70 +/- 40.56) and c-myc protein (71.49 +/- 41.11, r = 0.917 - 0.988, P < 0.001). All of them also increased correspondingly with the malignant degree of the tumors and level of PDGFB mRNA expression in the tumor cells (P < 0.05 - 0.01). Not only were the positive cell densities of PDGF alpha receptor (58.46 +/- 28.77), PDGF beta receptor (63.03 +/- 31.63) and phosphotyrosine protein (68.25 +/- 29.30) correlated positively with one another (r = 0.827 - 0.896, P < 0.001), but they also all correlated positively with the positive cell densities of PDGFB mRNA, c-fos mRNA, c-fos protein, c-myc mRNA and c-myc protein respectively (r = 0.615 - 0.888, P < 0.001).

CONCLUSIONS

The abnormally increased activity of the PDGFBB autocrine loop possibly upregulated the overexpression of c-fos and c-myc genes in glioma cells and suggested that c-fos and c-myc proteins probably played an important role as downstream response factors in the signaling pathway in which PDGFBB could induce gliocyte transformation and glioma development.

Effect of lithium on growth of bone marrow stromal cells

OBJECTIVE

To investigate the effect of lithium on the growth of bone marrow stromal cells.

METHODS

We compared the different effects of lithium with the concentration of 0.1-12 mmol/L on the growth of murine fibroblast colony forming unit (mCFU-F), human fibroblast colony forming unit (hCFU-F) and their intercolonial cells. Pure murine bone marrow stromal cell assay was used to investigate the mechanism.

RESULTS

Cultures with 1-4 mmol/L lithium resulted in significant increase in the number of hCFU-F, but distinct decrease in the number of mCFU-F. Furthermore, there were much more endothelial cells between mCFU-Fs than those between hCFU-Fs. The direct effect of 1-4 mmol/L lithium on the growth of pure murine fibroblasts and endothelial cells was stimulatory. Serum-free endothelial cell conditioned medium (EC-CM) could inhibit the growth of mCFU-F.

CONCLUSIONS

1-4 mmol/L lithium has stimulatory effect on the growth of pure murine fibroblasts and endothelial cells. The inhibitory effect of lithium on mCFU-F formation may result from the effect of increased endothelial cells.

Interactions of the novel antipsychotic aripiprazole (OPC-14597) with dopamine and serotonin receptor subtypes

OPC-14597 {aripiprazole; 7-(-4(4-(2,3-dichlorophenyl)-1-piperazinyl) butyloxy)-3,4-dihydro-2(1H)-quinolinone} is a novel candidate antipsychotic that has high affinity for striatal dopamine D2-like receptors, but causes few extrapyramidal effects. These studies characterized the molecular pharmacology of OPC-14597, DM-1451 (its major rodent metabolite), and the related quinolinone derivative OPC-4392 at each of the cloned dopamine receptors, and at serotonin 5HT6 and 5HT7 receptors. All three compounds exhibited highest affinity for D2L and D2S receptors relative to the other cloned receptors examined. Both OPC-4392 and OPC-14597 demonstrated dual agonist/antagonist actions at D2L receptors, although the metabolite DM-1451 behaved as a pure antagonist. These data suggest that clinical atypicality can occur with drugs that exhibit selectivity for D2L/D2S rather than D3 or D4 receptors, and raise the possibility that the unusual profile of OPC-14597 in vivo (presynaptic agonist and postsynaptic antagonist) may reflect different functional consequences of this compound interacting with a single dopamine receptor subtype (D2) in distinct cellular locales.

[Design of blood cell analyzers by using stationary suspending laser light scattering method]

The paper analyses the technology development of automatic blood cell analyzers, put forward the new method of blood cell counting and classification by stationary suspending laser light scattering. The new automatic blood cell analyser is designed by using this method. The design idea of the light route and data acquisition system is stressly provided in the paper. The calibration is performed by using the standard blood cell particulate.

Caspases in T-cell receptor-induced thymocyte apoptosis

Apoptosis eliminates inappropriate or autoreactive T lymphocytes during thymic development. Intracellular mediators involved in T-cell receptor (TCR)-mediated apoptosis in developing thymocytes during negative selection are therefore of great interest. Caspases, cysteine proteases that mediate mature T-cell apoptosis, have been implicated in thymocyte cell death, but their regulation is not understood. We examined caspase activities in distinct thymocyte subpopulations that represent different stages of T-cell development. We found caspase activity in CD4+CD8+ double positive (DP) thymocytes, where selection involving apoptosis occurs. Earlier and later thymocyte stages exhibited no caspase activity. Only certain caspases, such as caspase-3 and caspase-8-like proteases, but not caspase-1, are active in DP thymocytes in vivo and can be activated when DP thymocytes are induced to undergo apoptosis in vitro by TCR-crosslinking. Thus, specific caspases appear to be developmentally regulated in thymocytes.

Unmodified supported thiol/lipid bilayers: studies of structural disorder and conducting mechanism by cyclic voltammetry and AC impedance

Supported thiol/lipid bilayer assembly, one of the most spectacular bilayer systems in recent years, has provided a good model to study biomembranes because of its high mechanical stability. In this work, the structural and conducting property of unmodified Au supported octadecanethiol/phosphatidylcholine bilayers were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The forming process of bilayer was monitored by capacitance plane plot. The normalized membrane capacitance of supported bilayer is 0.52 microF cm(-2). Kinetically controlled voltammograms determined by Butler-Volmer equation were obtained for both thiol monolayer and thiol/lipid bilayer in linear sweep voltammetry. Results of EIS experiment indicate that collapsed sites and pinhole defects exist in thiol monolayer and lipid monolayer, respectively. The difference between the values of experimental and theoretical standard electron transfer rate constant indicates that the conducting mechanism of Au supported thiol monolayer is electron tunneling at collapsed sites. The conducting mechanism of Au supported thiol/lipid bilayer is attributed as the following: the electroactive species could diffuse through pinholes in the lipid monolayer and reach collapsed sites in thiol monolayer, where electron transfer occurs via a tunneling process. The fractional coverage of the lipid monolayer measure by EIS experiments is about 0.98 or higher.

A novel aminosteroid is active for proliferation inhibition and differentiation induction of human acute myeloid leukemia HL-60 cells

A novel aminosteroid, 2beta-(4'-methyl-1'piperazinyl)-3alpha,17beta-dihydroxyl+ ++-5alpha-androstane (HY), was found to inhibit proliferation of HL-60 leukemia cells and induce these cells to differentiate toward macrophage-like cells from the following evidence. (1) It inhibited HL-60 cell proliferation by cell counts, colony counts and MTT assay; (2) It caused morphological changes toward macrophage-like cells after culture for 6 days; (3) It induced NBT reduction activity; (4) It induced alpha-naphthyl acetate esterase activity and (5) it induced CD11b and CD14 expression indicated by flow cytometry analysis. There is potential for this novel aminosteroid in the treatment of myeloid leukemia.

Ben cao tu jing (Illustrated Canon of Herbology) and the origin of modern identification of Chinese materia medica

There is certain relation between the development of modern identification of Chinese materia medica and Ben cao tu jing. The purpose of Su Song's compilation of this book and the tasks of modern identification of Chinese materia medica, including the verification of genuineness, superiority of the drugs to ensure their qualities, are quite similar, and quite close in their contents. Suffice it to say that Ben cao tu jing made considerable contribution to modern identification of Chinese drugs, with a role of linking the past with the present.

Anorganic bovine bone supports osteoblastic cell attachment and proliferation

BACKGROUND

It was the aim of these studies to examine the ability of an anorganic bovine bone matrix material as an alternative to autogenous bone grafts and demineralized cadaver bone to support the attachment, spreading, and proliferation of isolated osteoblastic cells.

METHODS

Primary culture osteoblastic cells were isolated from neonatal rat calvaria by sequential collagenase digestion. In the attachment studies, cells which had been labeled with 3H-leucine were incubated with the matrix material in sterile microfuge tubes for 15, 90, or 180 minutes or 24 hours. The attached cells were released and the radioactivity measured by liquid scintillation spectrometry. In the proliferation experiments, the cells were cultured with the matrix material for 24 hours and 3H-thymidine was added during the last 2 hours of the incubation. The cells were released and the radioactivity measured by liquid scintillation spectrometry. Scanning electron microscopy (SEM) was employed to observe osteoblastic cell interaction with the anorganic bone matrix. In these studies the cells were seeded on the bone graft material, then the material was removed and processed for SEM after 30, 60 or 120 minutes, or 24 or 48 hours.

RESULTS

The cells attached to the matrix material in a time-dependent manner. There were significantly (P<0.05) more cells attached after 180 minutes than after the 15 and 90 minute incubations. The matrix material also supported proliferation of the attached osteoblastic cells. Cells seeded onto 100 mg of anorganic bovine bone resulted in significantly (P<0.05) more measurable proliferation than cells seeded onto 10 mg of material. The cells appeared to be round as they attached, then flatten and spread over time. There was also evidence of cellular processes extending into the pores of the material.

CONCLUSIONS

These results demonstrate that this anorganic bovine bone graft material is able to support the attachment and proliferation of osteoblastic cells.

[Evidence of increased endogenous carbon monoxide production in asthma]

OBJECTIVE

To investigate the role of carbon monoxide (CO) in the pathogenesis of asthma.

METHODS

We examined CO, nitrite and nitrate (NO2[not readable: see text]/NO3[not readable: see text]) and tumor necrosis factor alpha (TNF-alpha) levels in plasma of 26 asthmatic children and 22 matched normal children. At the same time, we examined the plasma and bronchoalveolar lavage fluid (BALF) CO, NO2[not readable: see text]/NO3[not readable: see text] and TNF-alpha levels in guinea-pigs with allergic asthma.

RESULTS

Asthmatic children in acute attack stage had increased levels of CO, NO2[not readable: see text]/NO3[not readable: see text] and TNF-alpha in plasma compared with normal control subjects (all P < 0.01), while in stable stage plasma CO and NO2[not readable: see text]/NO3[not readable: see text] reduced to normal levels (both of the P > 0.05), but TNF-alpha was still higher than the normal controls (P < 0.01). Guinea-pigs with allergic asthma had increased amounts of CO and TNF-alpha in plasma and CO, NO2[not readable: see text]/NO3[not readable: see text] and TNF-alpha in BALF as compared with normal control subjects (P < 0.05-0.01), but no changes in levels of circulating NO2[not readable: see text]/NO3[not readable: see text] (P > 0.05) were found. There was no difference between glucocorticoid treated asthmatic guinea pigs and normal controls in levels of CO, NO2[not readable: see text]/NO3[not readable: see text], and TNF-alpha. The elevation of plasma CO correlated with elevated NO2[not readable: see text]/NO3[not readable: see text] level in asthmatic children (P < 0.05), so did in the BALF in allergic guinea-pigs.

CONCLUSIONS

Our present data showed that endogenously produced CO was increased during the course of asthma, which suggested that the role of CO in asthma might worth further study.

Electron transfer between ferrocene-modified Au/octadecanethiol/lipid BLM electrode and redox couples in solution

Bilayers incorporated with ferrocene consisting of self-assembled octadecanethiol and lipid monolayer on gold substrates were fabricated. Its electrochemical behaviors in solutions containing different redox couples were investigated by cyclic voltammetry and ac impedance. The transmembrane electron transfer reaction across octadecanethiol self-assembled film and an adsorbed phospholipid layer mediated by ferrocene have been observed in the solution of Fe(CN)6(3-/4-). The formal potential difference between mediator in bilayer lipid membrane (BLM) and redox couple in solution has a great impact on the transmembrane electron transfer behavior. The ferrocene-modified BLM electrodes might be useful for constructing a bilayer-based electrochemical current rectifying device.

Desynchronizing responses to correlated noise: A mechanism for binaural masking level differences at the inferior colliculus

We examined the adequacy of decorrelation of the responses to dichotic noise as an explanation for the binaural masking level difference (BMLD). The responses of 48 low-frequency neurons in the inferior colliculus of anesthetized guinea pigs were recorded to binaurally presented noise with various degrees of interaural correlation and to interaurally correlated noise in the presence of 500-Hz tones in either zero or pi interaural phase. In response to fully correlated noise, neurons' responses were modulated with interaural delay, showing quasiperiodic noise delay functions (NDFs) with a central peak and side peaks, separated by intervals roughly equivalent to the period of the neuron's best frequency. For noise with zero interaural correlation (independent noises presented to each ear), neurons were insensitive to the interaural delay. Their NDFs were unmodulated, with the majority showing a level of activity approximately equal to the mean of the peaks and troughs of the NDF obtained with fully correlated noise. Partial decorrelation of the noise resulted in NDFs that were, in general, intermediate between the fully correlated and fully decorrelated noise. Presenting 500-Hz tones simultaneously with fully correlated noise also had the effect of demodulating the NDFs. In the case of tones with zero interaural phase, this demodulation appeared to be a saturation process, raising the discharge at all noise delays to that at the largest peak in the NDF. In the majority of neurons, presenting the tones in pi phase had a similar effect on the NDFs to decorrelating the noise; the response was demodulated toward the mean of the peaks and troughs of the NDF. Thus the effect of added tones on the responses of delay-sensitive inferior colliculus neurons to noise could be accounted for by a desynchronizing effect. This result is entirely consistent with cross-correlation models of the BMLD. However, in some neurons, the effects of an added tone on the NDF appeared more extreme than the effect of decorrelating the noise, suggesting the possibility of additional inhibitory influences.

[Optimum choice for the cultivation of CFU-GM in media buffered with HEPES]

The effects of media buffered with HEPES of different concentrations and different incubation periods on the proliferation and differentiation of CFU-GM were studied under the standard condition for culture. The results exhibited that when the incubation period prolonged, the pH values of culture system raised and the colony formation of CFU-GM decreased; the culture system added with proper HEPES buffer solution could maintain and increase the colony formation of CFU-GM, especially the culture system in which the pH value was not adjusted before the experiment. We also found that media buffered with HEPES could change the ratio of different colony types. This showed that media buffered with HEPES could not only stimulate the proliferation of CFU-GM, but also affect its differentiation. The results suggest that media buffered with HEPES are better than those without HEPES for the culture of hematopoietic progenitor cells, and the optimum concentration is 10-20 mmol.L-1.

[Effects of subretinal fluid containing proteins with different molecular weights on the proliferative vitreoretinopathy]

The stimulating effects of subretinal fluid (SRF) containing different molecular weight proteins which were isolated by fast performance liquid chromatography (FPLC) and ultrafiltration on the proliferative vitreoretinopathy (PVR) were investigated. The results showed that (1) the PVR was induced by 10-30 kD proteins injecting vitreously, and the forming duration of PVR was about two weeks; (2) the location of inducing PVR was mainly on medullary ray area in the rabbit eye; (3) In the SRF there were growth factors which were mainly those proteins with molecular weight between 10 kD and 30 kD.

[An automatic method segmenting lung regions from digital chest radiograph]

It is difficult to process digital chest image with ordinary method because of the wide dynamic range of chest radiograph. Anatomically adaptive processing is a better method for chest image, but it needs automatic segmentation of the image. In this paper, an effective method for segmenting lung regions from digital chest radiograph is presented. This method automatically calculates the lung/mediastinum-subdiaphragmatic threshold according to the histogram of chest image processed.

Autocrine transforming growth factor alpha provides a growth advantage to malignant cells by facilitating re-entry into the cell cycle from suboptimal growth states

CBS human colon carcinoma cells are poorly tumorigenic in athymic nude mice, whereas FET colon carcinoma cells are non-tumorigenic. Both cell lines have well differentiated properties in tissue culture. Transforming growth factor alpha (TGF-alpha) was ectopically expressed by stable transfection of a TGF-alpha cDNA under repressible tetracycline control. The TGF-alpha-transfected cells showed enhanced clonal initiation and shortened lag phase growth in tissue culture without an alteration in doubling time in exponential phase relative to untransfected cells. Furthermore, the TGF-alpha transfectants showed increased independence from exogenous growth factors in clonal growth assays and induction of DNA synthesis after release from quiescence. Growth factor independence was associated with sustained epidermal growth factor receptor activation in quiescent TGF-alpha-transfected cells and the requirement of exogenous insulin for stimulation of quiescent cells to re-enter the cell cycle. Higher cloning, reduced lag time in tissue, and the acquisition of growth factor independence for DNA synthesis without a change in doubling time of TGF-alpha-transfected cells indicate that autocrine TGF-alpha functions by facilitating re-entry into the cell cycle from sub-optimal growth states rather than promoting or controlling the proliferation of actively cycling cells. The modulation of growth regulation by autocrine TGF-alpha was associated with increased malignant properties as TGF-alpha transfectants showed increased tumorigenicity in athymic nude mice. The administration of tetracycline reversed the effects of TGF-alpha expression in these cells both in vivo and in vitro, indicating that the alterations of the biological properties were due to the expression of TGF-alpha. Since these cells are continuously grown in a completely chemically defined medium without serum supplementation, it was possible to assign the mechanism underlying the generation of growth factor independence to the replacement of a requirement for exogenous insulin in parental cells by autocrine TGF-alpha.