[Analysis on chemical composition of genus Pueraria stems from China]

OBJECTIVE

To provide scientific basis for developing and utilizing Pueraria stems.

METHOD

The contents of total flavonoid were determined by means of UV spectrophotometry. The isoflavones in stems and roots of nine species of genus Pueraria were analyzed by TLC.

RESULTS

The stems and roots are similar in chemical composition.

CONCLUSION

Pueraria stems as a potential resource could be used as a substitute for Pueraria roots.

Calcium influx factor is synthesized by yeast and mammalian cells depleted of organellar calcium stores

Depletion of endoplasmic reticulum Ca2+ stores leads to the entry of extracellular Ca2+ into the cytoplasm, a process termed capacitative or store-operated Ca2+ entry. Partially purified extracts were prepared from the human Jurkat T lymphocyte cell line and yeast in which Ca2+ stores were depleted by chemical and genetic means, respectively. After microinjection into Xenopus laevis oocytes, the extracts elicited a wave of increased cytoplasmic free Ca2+ ([Ca2+]i) that spread from the point of injection across the oocyte. Extracts from cells with replete organellar Ca2+ stores were inactive. The increases depended on extracellular Ca2+, were unaffected by the inositol 1,4,5-trisphosphate (IP3) inhibitor heparin or an anti-IP3 receptor antibody and were unchanged when the endoplasmic reticulum was segregated to the hemisphere opposite the injection site by centrifugation. Confocal microscopy revealed that [Ca2+]i increases were most pronounced at the periphery of the oocyte. The patterns of [Ca2+]i increases were replicated by computer simulations based on a diffusible messenger of about 700 Da that directly activates Ca2+ influx. In addition, ICRAC, a Ca2+ release-activated Ca2+ current monitored in Jurkat cells by whole-cell patch clamp recordings, was more rapidly activated when active extracts were included in the patch pipette than by the inclusion of a Ca2+ chelator or IP3. These data support the existence in yeast and mammalian cells depleted of Ca2+ stores of a functionally conserved diffusible calcium influx factor that directly activates Ca2+ influx.

Molecular recognition of angiogenesis inhibitors fumagillin and ovalicin by methionine aminopeptidase 2

Angiogenesis inhibitors are a novel class of promising therapeutic agents for treating cancer and other human diseases. Fumagillin and ovalicin compose a class of structurally related natural products that potently inhibit angiogenesis by blocking endothelial cell proliferation. A synthetic analog of fumagillin, TNP-470, is currently undergoing clinical trials for treatment of a variety of cancers. A common target for fumagillin and ovalicin recently was identified as the type 2 methionine aminopeptidase (MetAP2). These natural products bind MetAP2 covalently, inhibiting its enzymatic activity. The specificity of this binding is underscored by the lack of inhibition of the closely related type 1 enzyme, MetAP1. The molecular basis of the high affinity and specificity of these inhibitors for MetAP2 has remained undiscovered. To determine the structural elements of these inhibitors and MetAP2 that are involved in this interaction, we synthesized fumagillin analogs in which each of the potentially reactive epoxide groups was removed either individually or in combination. We found that the ring epoxide in fumagillin is involved in the covalent modification of MetAP2, whereas the side chain epoxide group is dispensable. By using a fumagillin analog tagged with fluorescein, His-231 in MetAP2 was identified as the residue that is covalently modified by fumagillin. Site-directed mutagenesis of His-231 demonstrated its importance for the catalytic activity of MetAP2 and confirmed that the same residue is covalently modified by fumagillin. These results, in agreement with a recent structural study, suggest that fumagillin and ovalicin inhibit MetAP2 by irreversible blockage of the active site.

Sarcoplasmic reticulum function in murine ventricular myocytes overexpressing SR CaATPase

To examine the effects of the overexpression of sarcoplasmic reticulum (SR) CaATPase on function of the SR and Ca2+ homeostasis, we measured [Ca2+]i transients (fluo-3), and L-type Ca2+ currents (ICa.L), Na/Ca exchanger currents (INa/Ca), and SR Ca2+ content with voltage clamp in ventricular myocytes isolated from wild type (WT) mice and transgenic (SRTG) mice. The amplitude of [Ca2+]i transients was insignificantly increased in SRTG myocytes, while the diastolic [Ca2+]i tended to be lower. The initial and terminal declines of [Ca2+]i transients were significantly accelerated in SRTG myocytes, implying a functional upregulation of the SR CaATPase. We examined the functional contribution of only the SR CaATPase to the initial and the terminal phase of the decline of [Ca2+]i, by abruptly inhibiting Na/Ca exchange with a rapid switcher device. The rate of [Ca2+] decline mediated by the SR CaATPase was increased by 40% in SRTG compared with WT myocytes. The function of the L-type Ca2+ channel was unchanged in SRTG myocytes, while INa/Ca density was slightly (10%) decreased. Measured SR Ca2+ content was significantly increased by 29% in SRTG myocytes. Thus, overexpression of SR CaATPase markedly accelerates the decline of [Ca2+]i transients, and induces in increase in SR Ca2+ content, with some downregulation of the Na/Ca exchanger.

Influence of prior Na+ pump activity on pump and Na+/Ca2+ exchange currents in mouse ventricular myocytes

We examined the dependence of peak Na+ pump and Na+/Ca2+ exchanger currents on prior Na+ pump inhibition induced by exposure to zero extracellular K+ in voltage-clamped adult murine ventricular myocytes. Abrupt activation of the Na+ pump by reexposure of myocytes to extracellular K+ with a rapid solution switcher resulted in the development of a transient peak current at approximately 500 ms, followed by a decline over 1-2 min to a steady-state level. The magnitudes of both the peak Na+ pump current (Ip) and the peak outward Na+/Ca2+ exchange current, activated by rapidly reducing extracellular Na+ to zero with the solution switcher, were dependent on previous Na+ pump activity. [Na+] gradients (Na+-binding benzofuran isophthalate fluorescence) between the patch pipette and the bulk cytosol were relatively small and could not account for the large differences between peak and steady-state Ip and reverse Na+/Ca2+ exchanger currents. Our results are consistent with the presence of a subsarcolemmal Na+ concentration gradient, which is similar for the Na+ pump and the Na+/Ca2+ exchanger. These findings also support the hypothesis that the Na+ pump and the Na+/Ca2+ exchanger are colocalized in the sarcolemma.

[Physicochemical changes in the process of preparing traditional Chinese drugs]

OBJECTIVE

Summarizing the physicochemical changes in the process of preparing traditional Chinese drugs and affording useful clues for the quality improvement of Chinese patent drugs.

METHOD

Introducing the main physicochemical changes, such as precipitating reaction, solubility increasing, hydrolysis, and oxidation-reduction etc., which occur in the process of extracting, separating, concentrating and drying.

RESULT AND CONCLUSION

The research of physicochemical changes occurring in the process of preparation and the probe into their mechanism play an important role in perfecting the basic theories of Chinese pharmacy, promoting the development of compatibility theory of Chinese pharmacy and improving the technology design for preparing and controlling the quality of Chinese patent drugs.

Abnormal myocyte Ca2+ homeostasis in rabbits with pacing-induced heart failure

To determine whether there are abnormalities in myocyte excitation-contraction coupling and intracellular Ca2+ concentration ([Ca2+]i) homeostasis in pacing-induced heart failure (PF), we measured L-type Ca2+ current (ICa,L) and Na+/Ca2+ exchanger current (INa/Ca) with voltage clamp and measured intracellular Na+ concentration ([Na+]i) and [Ca2+]i with the use of sodium-binding benzofuran isophthalate (SBFI) and fluo 3 in ventricular myocytes isolated from control and paced rabbits. The peak systolic and diastolic levels and the amplitude of electrically stimulated [Ca2+]i transients (0.25 Hz, extracellular Ca2+ concentration = 1.08 mM) were significantly less in PF myocytes. Also, there was prolongation of the times to peak and decline of [Ca2+]i transients. ICa,L density was markedly decreased in PF myocytes. INa/Ca at -40 mV elicited by rapid exposure to 0 Na+ solution with a rapid solution switcher was significantly reduced in PF myocytes, suggesting that the function of the Na+/Ca2+ exchanger is impaired in these myocytes. In PF myocytes the decline of the [Ca2+]i transient when the Na+/Ca2+ exchanger was abruptly disabled was markedly prolonged compared with the decline in control myocytes, consistent with depressed sarcoplasmic reticulum (SR) Ca2+-ATPase function. RNase protection assay showed decreased levels of Na+/Ca2+ exchanger and SR Ca2+-ATPase mRNA in PF hearts, consistent with the function studies. We conclude that the functions of L-type Ca2+ channels, Na+/Ca2+ exchanger, and SR Ca2+-ATPase are impaired in myocytes from rabbit hearts with failure induced by rapid pacing. These abnormalities result in reduced [Ca2+]i transients and systolic and diastolic dysfunction and appear to account for the abnormal ventricular function observed.

Stroke-prone renovascular hypertensive rats

PURPOSE

To summarized the methods for establishment, characteristics of vascular lesions in brain and heart and the application of stroke-prone renovascular hypertensive rats (RHRSP).

DATA SOURCES AND METHODS

Most published original articles about RHRSP in our laboratory were reviewed.

RESULTS

After the renal arteries were constricted bilaterally with ring-shape silver clips, the stroke-prone renovascular hypertensive rats were established. Hypertension was produced in all RHRSP (100%). The peak of blood pressure in RHRSP reached 29.1 +/- 3.0 kPa. The lesions of cerebral arteries and arterioles and the damage of cerebral capillary structure by hypertension were observed in the RHRSP. The incidence of spontaneous stroke was 56.4% within 40 weeks after the renal artery constriction. Left ventricular hypertrophy and small coronary arterial lesions in myocardium were discovered in all RHRSP. Myocardial infarction occurred spontaneously in 41.8% of RHRSP. The animal models have been used for the studies on mechanisms of stroke and myocardial infarction.

CONCLUSIONS

Because the vascular lesions in cerebrum and heart in RHRSP are similar to that in human beings with hypertension, RHRSP can be used in the studies on mechanisms of hypertensive arteriosclerotic stroke and cardiac lesions and on verifying the effects of different medications to complications of hypertension, and the results might be more reliable than that in animal models without hypertension.

Peroxynitrite is not a major mediator of endothelial cell injury by activated neutrophils in vitro

OBJECTIVE

Human polymorphonuclear leukocytes (PMN) produce nitric oxide (NO), superoxide (O2.-) and peroxynitrite (ONOO-) upon stimulation. We investigated the role of ONOO- in PMN-induced injury to cultured bovine aortic endothelial cells (BAEC).

METHODS

BAEC were cocultured with phorbol 12-myristate 13-acetate (PMA)-activated human PMN (effector-to-target ratio, 10:1) and injury to BAEC was evaluated at intervals by 51Cr release assay. The levels of NO, O2.-, ONOO- and nitrotyrosine, a reaction product of ONOO-, were also measured, and the influence of NO synthase inhibitors, O2.- and hydroxyl radical scavengers and other effectors was examined.

RESULTS

In BAEC cocultured with PMA-activated PMN, 51Cr release was significantly increased [14.6 +/- 2.2% at 2 h (p < 0.05) and 42.6 +/- 2.7% at 4 h (p < 0.01); control (nonactivated PMN), < 4%]. Superoxide dismutase (100 U/ml) reduced 51Cr release to 4.6 +/- 2.2% at 2 h (p < 0.05). N-Iminoethyl-L-ornithine (L-NIO, 0.1 mM) potentiated 51Cr release (30.6 +/- 3.8% at 2 h, p < 0.01), and the potentiation was eliminated by anti-CD18 monoclonal antibody. The 51Cr release was completely prevented by dimethyl sulfoxide or by deferoxamine. Treatment of PMN with L-NIO inhibited NO generation and increased O2.- production. The nitrotyrosine level did not increase in BAEC cocultured with PMA-activated PMN.

CONCLUSION

NO-derived ONOO- is not a major cytotoxic mediator in BAEC injury by activated PMN. NO may have a cytoprotective effect by inhibiting PMN adherence to endothelial cells.

[Isolation and observation of ciliated cells from guinea pig's nasal epithelium]

OBJECTIVE

To investigate nasal physiological function at a cellular level and to establish a method for isolating single ciliated cells from guinea pig's nasal epithelium.

METHODS

The ciliated cells were isolated by means of mechanical dissociation after papain treatment and a differential interference contrast (DIC) microscope was used for 1000-fold observation (objective lens: 100-fold; eye piece: 10-fold).

RESULTS

A total of 12,587 single ciliated cells could be isolated from nasal epithelium of each guinea pig. The criteria for good viability of isolated nasal ciliated cells include: (1) actively motile cilia; (2) a smooth cytoplasmic membrane; (3) cytoplasm in a state of translucence (birefringence); (4) cells neither swollen nor shrunk. With short term culture at room temperature, the isolated nasal ciliated cells retained a good viability for 2-9 hours or longer. The living ciliated cells showed swing motions of cilia with fast and slow phases at a rate of 51-119 times per minute.

CONCLUSION

A method for isolating ciliated cells from guinea pig's nasal epithelium and a criteria for good viability of isolated ciliated cells have been established. Ciliary motion pattern and ciliary beating frequency were also studied.

Two-kidney, two clip renovascular hypertensive rats can be used as stroke-prone rats

BACKGROUND AND PURPOSE

The cerebrovascular lesions in stroke-prone spontaneously hypertensive rats are not only dependent on high blood pressure but partly related to pressure-independent genetic factors. The aim of the present study was to observe whether spontaneous stroke occurred in renovascular hypertensive rats without a genetic deficiency.

METHODS

The 1-kidney, 1 clip (1k1c); 2-kidney, 1 clip (2k1c); and 2-kidney, 2 clip (2k2c) methods were used to induce hypertension in male Sprague-Dawley rats with a ring-shaped silver clip. Sham-operated rats were used as controls. Blood pressure and neurological symptoms were observed in the rats without any artificial inducement. Brain sections stained with hematoxylin-eosin and phosphotungstic acid-hematoxylin were examined under a microscope to determine stroke foci.

RESULTS

The attack rate of stable hypertension was 100% (55/55) in the 2k2c group, which was significantly higher than that in the 1k1c (23/30, 76.7%) and 2k1c (21/30, 70%) groups (P<0.01). None of the rats in the 2k2c group died of acute renal failure or suffered from diffuse cerebral lesions postoperatively. Forty weeks after renal artery constriction, the incidence of spontaneous stroke in the 2k2c group was 61.8% (34/55), which was significant higher than that in the 1k1c (7/30, 23.3%) and 2k1c (5/30,16.7%) groups (P<0.01). Stroke foci were not observed in normotensive controls.

CONCLUSIONS

We conclude that 2k2c renovascular hypertensive rats with proper renal artery constriction can be used as stroke-prone renovascular hypertensive rats independent of a genetic deficiency.

Synthetic analogues of TNP-470 and ovalicin reveal a common molecular basis for inhibition of angiogenesis and immunosuppression

TNP-470 (1), a synthetic derivative of the natural product fumagillin (2), potently inhibits angiogenesis in vivo and the growth of endothelial cell cultures in vitro. The structurally related natural product ovalicin (3) also inhibits angiogenesis but possesses potent immunosuppressive activity. The recent finding that all three drugs bind and inhibit the same target, methionine aminopeptidase 2 (MetAP2), raised the question of whether TNP-470 is also immunosuppressive and whether inhibition of MetAP2 underlies both activities of ovalicin. To address these questions, we synthesized a series of analogues of TNP-470 and ovalicin and tested them for their abilities to inhibit the proliferation of either endothelial cell or mixed lymphocyte cultures. TNP-470 and its analogues were found to possess both immunosuppressive and anti-angiogenic activities. A strong correlation was observed between the ability of compounds to inhibit bovine and human endothelial cell growth and their ability to inhibit the mouse mixed lymphocyte reaction (MLR), implying that the two activities share a common molecular basis, i.e., inhibition of MetAP2. Interestingly, ovalicin and several other compounds behaved differently in the human MLR than in either the mouse MLR or human endothelial cell proliferation assays, pointing to possible species-specific and cell type-specific differences in the metabolism or uptake of these compounds.

[Diagnostic significance of cuticular patterns on corolla surface from Pueraria spp]

OBJECTIVE

To provide reference materials for the classification and identification of Pueraria spp. by studying the cuticular patterns on corolla surface.

METHOD

The cuticular patterns of corolla were observed under SEM (scanning electron microscope).

RESULT

The species of the genus Pueraria are defferent from each other in cuticular patterns.

CONCLUSION

The diagnostic characters of the cuticular patterns on corolla surface can be used for the classification and identification of Pueraria spp.

[The cochlea in short-term culture]

In order to establish organotypic culture of the cochlea, the dissection of the early postnatal mouse cochlea and its morphology in short-term culture were investigated. The viability of hair cells in the culture was assessed using differential interference contrast (DIC) microscopy and double-staining with fluorescein diacetate (FDA) and propidium iodide (PI). The hair cells remained viable and did not show any signs of damage for up to 8-18 hours. When incubated in Hank's solution containing 1 mmol/L dihydrostreptomycin, the hair cells initially deteriorated in 0.5-4.5 hours and progressed to entire degeneration after 10-20 hours. In addition to its utilization in organotypic culture, the cochlea in short-term culture can be used as a valuable model for studying cellular and molecular neurobiology of the inner ears.

Effects of angiotensin II on intracellular calcium and contracture in metabolically inhibited cardiomyocytes

Angiotensin II (A-II) is known to potentiate ischemic dysfunction during ischemia, but the mechanisms involved are not completely established. We examined the effects of A-II on intracellular calcium concentration ([Ca++]i) and cell contracture caused by metabolic inhibition in isolated adult rabbit ventricular myocytes. [Ca++]i was assessed by flow cytometry, using the Ca(++)-sensitive fluorescent probe, fluo-3. After 90 min of exposure to 2 mM cyanide (CN) and 0 glucose, there was a significant increase in myocyte [Ca++]i. This increase was slightly augmented in the presence of 100 nM A-II. In the presence of partial Na+/K+ ATP pump inhibition ([K+]o = 0.8 mM), there was a more significant increase in [Ca++]i associated with exposure to CN + A-II vs. CN alone. Similar results were obtained with CN plus 2-deoxyglucose, and the effect of A-II was inhibited by 10 microM 5-(N-ethyl-N-isopropyl)amiloride. Myocytes exposed to 2 mM CN and 0 glucose gradually developed contracture over a 3-hr period. Addition of 100 nM A-II significantly (P < .01) enhanced loss of rod shape morphology during 3 hr of CN exposure. Partial inhibition of the Na+ pump by exposure to 0.8 mM K+ had no effect on myocyte survival in the absence of CN, but augmented the harmful effect of A-II on cell contracture caused by CN exposure. This effect of A-II was completely reversed by the addition of 1 mM amiloride, a Na+/H+ exchange inhibitor. We conclude that A-II directly enhances cell injury during CN exposure in isolated rabbit ventricular myocytes. We postulate that this effect of A-II is mediated by stimulation of Na+/H+ exchange with resultant increased [Na+]i and subsequent [Ca++]i loading, possibly via reverse Na+/Ca++ exchange.

Effects of overexpression of the Na+-Ca2+ exchanger on [Ca2+]i transients in murine ventricular myocytes

We measured [Ca2+]i and [Na+]i in isolated transgenic (TG) mouse myocytes overexpressing the Na+-Ca2+ exchanger and in wild-type (WT) myocytes. In TG myocytes, the peak systolic level and amplitude of electrically stimulated (ES) [Ca2+]i transients (0.25 Hz) were not significantly different from those in WT myocytes, but the time to peak [Ca2+]i was significantly prolonged. The decline of ES [Ca2+]i transients was significantly accelerated in TG myocytes. The decline of a long-duration (4-s) caffeine-induced [Ca2+]i transient was markedly faster in TG myocytes, and [Na+]i was identical in TG and WT myocytes, indicating that the overexpressed Na+-Ca2+ exchanger is functionally active. The decline of a short-duration (100-ms) caffeine-induced [Ca2+]i transient in 0 Na+/0 Ca2+ solution did not differ between the two groups, suggesting that the sarcoplasmic reticulum (SR) Ca2+-ATPase function is not altered by overexpression of the Na+-Ca2+ exchanger. There was no difference in L-type Ca2+ current density in WT and TG myocytes. However, the sensitivity of ES [Ca2+]i transients to nifedipine was reduced in TG myocytes. This maintenance of [Ca2+]i transients in nifedipine was inhibited by Ni2+ and required SR Ca2+ content, consistent with enhanced Ca2+ influx by reverse Na+-Ca2+ exchange, and the resulting Ca2+-induced Ca2+ release from SR. The rate of rise of [Ca2+]i transients in nifedipine in TG myocytes was much slower than when both the L-type Ca2+ current and the Na+-Ca2+ exchange current function together. In TG myocytes, action potential amplitude and action potential duration at 50% repolarization were reduced, and action potential duration at 90% repolarization was increased, relative to WT myocytes. These data suggest that under these conditions, overexpression of the Na+-Ca2+ exchanger in TG myocytes accelerates the decline of [Ca2+]i during relaxation, indicating enhanced forward Na+-Ca2+ exchanger function. Increased Ca2+ influx also appears to occur, consistent with enhanced reverse function. These findings provide support for the physiological importance of both these modes of Na+-Ca2+ exchange.

Antisense inhibition of the PTI-1 oncogene reverses cancer phenotypes

The genetic alterations and molecular events mediating human prostate cancer development and progression remain to be defined. Rapid expression cloning and differential RNA display detect a putative oncogene, prostate tumor-inducing gene 1 (PTI-1), that is differentially expressed in human prostate (as well as breast, colon, and small cell lung) cancer cell lines, patient-derived prostate carcinomas, and blood from patients with metastatic prostate cancer. PTI-1 consists of a unique 5' untranslated region (5' UTR) with significant sequence homology to Mycoplasma hyopneumoniae 23S ribosomal RNA juxtaposed to a sequence that encodes a truncated and mutated human elongation factor 1alpha (Trun-EF). Stable expression of a nearly full-length 1.9-kb PTI-1 gene, but not the separate PTI-1 5' UTR or Trun-EF region, in normal rat embryo fibroblast cells, CREF-Trans 6, induces an aggressive tumorigenic phenotype in athymic nude mice. Blocking PTI-1 expression with antisense PTI-1 results in reversion of transformed PTI-1-expressing cells to a more normal cellular morphology with suppression in both anchorage-independent growth and tumorigenic potential in athymic nude mice. These findings document that PTI-1 is indeed an oncogene, and directly blocking PTI-1 expression can nullify cancer phenotypes. In these contexts, PTI-1 not only represents a gene with discriminating diagnostic properties but also may serve as a target for the gene-based therapy of human prostate and other cancers.

Oxygen transfer characteristics in the compact callus aggregates of Rhodiola sachalinensis

The effective diffusivity of oxygen in compact callus aggregates (CCA) of Rhodiola sachalinensis was extremely small, varying from 0.34 x 10(-11) to 5.4 x 10(-9) m2/s and increasing with particle diameter. The calculated results indicated that severe oxygen limitations occurred in the CCA aggregates. However, the direct determination of the viability of the cells demonstrated that the CCA aggregates contained a high fraction of viable cells. It was suggested that the tissue differentiation or plasmodesmata within the CCA aggregates may provide capillaries for improving transport of oxygen and other nutrients.

[Observation on inhibitory effect of tetrandrine on the growth of human skin fibroblast in vitro]

The effect of tetrandrine on the growth of human skin fibroblasts was observed in vitro culture. The result revealed that tetrandrine significantly inhibited the growth of fibroblast. The higher the concentration of tetrandrine, the higher the inhibition rate, forming a time-dependent relationship. The possible value of tetrandrine in the treatment of hypertrophic scar is discussed.

[Separation of soybean agglutinin by hydrophobic-interaction chromatography]

The soybean agglutinin (SBA) was separated with hydrophobic-interaction chromatography (HIC) in this work. HIC of the crude lectin extract of SBA was performed on Phenyl-Sepharose CL-4B column, 10 cm x 2.5 cm i.d., at a flow-rate of 1.0 mL/min. A 20 mL sample of the crude extract was applied to the column previously equilibrated with the buffer, 0.01 mol/L PBS containing ammonium sulfate (60% of saturation concentration). The column was eluted with the starting buffer, then with the buffer containing 30% saturation of ammonium sulfate, and finally with 0.01 mol/L PBS. Fractions were detected by UV absorbance at 280 nm and assayed for hemagglutinating activity. The results show that the purification-fold was as high as 35 and the recovery of activity was 100%.

Genetic and immunological adaptation of Heligmosomoides polygyrus in mice

Two lines of Heligmosomoides polygyrus, QN and QA, were selected by passage, respectively, through naive and immune Quackenbush (Q) mice and their biology and capacity to induce immune responses in homologous Q and heterologous low- (SL) and high-responder (RH) mice were assessed. QA H. polygyrus survived the impact of otherwise protective immunity in Q mice better than did QN parasites, especially after a secondary infection. The enhanced survival of QA parasites was observed also in SL but not in RH mice. Infections with QA phenotypes induced a reduced antibody response and lower eosinophilia compared to QN parasites in Q mice. The total numbers of nucleated cells in the mesenteric lymph node (MLN) and spleen increased to different extents according to the genotype of the mice and the phenotype of parasite used: the increase was most profound in RH, least in SL and intermediate in Q mice; QN induced more lymphocytosis in the MLN and spleen than did QA parasite phenotypes. B cells from MLN and spleen, stained with fluorochrome-conjugated antibody against mouse Ig, showed increased intensity of fluorescence in the flow cytometric assay after infection with H. polygyrus, but to different degrees: the intensity increased most in RH and least in SL mice; more in Q mice infected with QN than with QA H. polygyrus. These results suggest that adaptation of parasites to immunity of the host is associated with reduction of their immunogenicity and is specific to the immune status and genotype of the host to which the parasites have become adapted.

Methionine aminopeptidase (type 2) is the common target for angiogenesis inhibitors AGM-1470 and ovalicin

BACKGROUND

Angiogenesis, the formation of new blood vessels, is essential for tumor growth. The inhibition of angiogenesis is therefore emerging as a promising therapy for cancer. Two natural products, fumagillin and ovalicin, were discovered to be potent inhibitors of angiogenesis due to their inhibition of endothelial cell proliferation. An analog of fumagillin, AGM-1470, is currently undergoing clinical trials for the treatment of a variety of cancers. The underlying molecular mechanism of the inhibition of angiogenesis by these natural drugs has remained unknown.

RESULTS

Both AGM-1470 and ovalicin bind to a common bifunctional protein, identified by mass spectrometry as the type 2 methionine aminopeptidase (MetAP2). This protein also acts as an inhibitor of eukaryotic initiation factor 2alpha (elF-2alpha) phosphorylation. Both drugs potently inhibit the methionine aminopeptidase activity of MetAP2 without affecting its ability to block elF-2alpha phosphorylation. There are two types of methionine aminopeptidase found in eukaryotes, but only the type 2 enzyme is inhibited by the drugs. A series of analogs of fumagillin and ovalicin were synthesized and their potency for inhibition of endothelial cell proliferation and inhibition of methionine aminopeptidase activity was determined. A significant correlation was found between the two activities.

CONCLUSIONS

The protein MetAP2 is a common molecular target for both AGM-1470 and ovalicin. This finding suggests that MetAP2 may play a critical role in the proliferation of endothelial cells and may serve as a promising target for the development of new anti-angiogenic drugs.

H-2 genes and resistance to infection with Heligmosomoides polygyrus in selectively bred mice

Two lines of mice bred selectively for high resistance (RH) and susceptibility (SL) to reinfection with Heligmosomoides polygyrus demonstrated disparate levels of resistance to infection but did not differ in the frequency of H-2 antigens when assayed with antisera against antigens of 5 inbred H-2 haplotypes. The selected RH and SL mice were crossbred with, and backcrossed to, the inbred CBA mice. F1 mice from crosses between RH and CBA were as resistant to reinfection with H. polygyrus as their RH parents. F1 mice from crosses between SL and CBA were more resistant than either of their parents. BC1 mice were either positive or negative for H-2 antigens from RH and SL mice. BC1 mice that were positive for RH H-2 antigens were more resistant to infection than their negative littermates, but they were significantly more susceptible to infection with H. polygyrus than their F1 parents. These results demonstrated that genes within and mapped outside H-2 complex control the level of resistance to H. polygyrus in the selected mice and suggested that selective breeding of mice for resistance fixed the relevant genes in and outside the H-2 complex.

[Liver-protective activity of Aralia taibaiensis Z.Z. Wang et H.C. Zheng]

Compared with oleanolic acid and sodium chloride physiological solution, the water decoction of and the total saponin in root and cortex of Aralia taibaiensis were testified to have significant protective activity in experimental acute liver injury in mice induced by CCl4.

[Resources survey of medicinal species from genus Aralia]

This paper deals with the distribution area, growing environment and medicinal parts of 19 species and 1 variety, including 2 new species of genus Aralia. An index for identification of these medicinal species is presented.

High density lipoproteins increase cytoplasmic free calcium in bovine aortic endothelial cells

This study examined the influence of human high density lipoproteins (HDL) on the intracellular free calcium of cultured bovine aortic endothelial cells (BAECs). Intracellular Ca2+ concentration ([Ca2+]i) was determined by a fluorescent calcium indicator, Fura-2. It was found that, in the presence of 1 mmol/L extracellular calcium, HDL resulted in a biphasic elevation of [Ca2+]i in BAECs, consisting of an initial, transient component followed by a lower, but more sustained component. Doses of HDL from 25 to 200 micrograms protein/ml induced marked concentration-dependent elevations of [Ca2+]i in BAECs. The sustained component was abolished by deprivation of extracellular calcium or by pretreatment of endothelial cells with a calcium influx blocker, NiCl2, HDL-induced elevation of [Ca2+]i was attenuated in a concentration-dependent way by an inhibitor of calcium release, tetracaine. Repeated applications of HDL (100 micrograms protein/ml) markedly blunted the initial peak component of the calcium transient of BAECs. These results demonstrate that both intracellular and extracellular calcium pools are responsible for the biphasic elevation of [Ca2+]i induced by HDL in cultured BAECs.

[Interspecific difference and intraspecific variation of coumarins in Cnidium species]

According to the results of TLC and assay of coumarins, the interspecific difference of coumarins in 4 Cnidium species is obvious, and 4 chemotypes have been found in Cnidium monnieri.

Peroxynitrite formation from activated human leukocytes

We showed direct evidence of peroxynitrite formation from polymorphonuclear cells (PMN) with the nitration of 4-hydroxyphenylacetic acid (HPA) to 4-hydroxy-3-nitrophenylacetic acid (NO2HPA). Human PMN from healthy volunteers was stimulated with phorbol-12-myristate-13-acetate (PMA, 10 ng/ml) at 37 degrees C in 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid-buffered Hank's balanced salt solution (pH 7.4) with HPA (1 mM). NO2HPA was detected under PMA stimulation only in the presence of myeloperoxidase inhibitor. NO2HPA was eliminated by N-monomethyl-L-arginine (100 microM). The inhibition of myeloperoxidase appears to be essential to demonstrate the production of NO2HPA since myeloperoxidase itself or its product, hypochlorite, reacted with peroxynitrite and hampered the formation of NO2HPA.

Biosynthesis of the unusual amino acid (4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine of cyclosporin A: enzymatic analysis of the reaction sequence including identification of the methylation precursor in a polyketide pathway

3(R)-Hydroxy-4(R)-methyl-6(E)-octenoic acid, the C9-backbone of the unusual amino acid (4R)-4-[(E)-2-butenyl]-4-methyl-L-threonine (Bmt), is biosynthesized as a coenzyme A thioester from acetyl-CoA, malonyl-CoA, NADPH, and S-adenosylmethionine via a polyketide pathway. Here we present detailed enzymatic studies about the basic assembly process. After attachment of the activated building units to Bmt polyketide synthase the intermediates remained enzyme-bound throughout the cycle. Premature cutoff of biosynthesis led to the release of the intermediates from the enzyme, either as coenzyme A thioesters or, in the case of reactive C8-intermediates, as lactones. Enzyme-bound 3-oxo-4-hexenoic acid, the condensation product of the second elongation cycle, could be identified as the exclusive substrate for the introduction of the methyl group. Part of the biosynthesis including the first elongation cycle, the second condensation reaction, and the methylation step was shown to follow a processive mechanism. All activated intermediates of this processive part could be introduced into the correct pathway at the respective steps, whereas 2-methyl-3-oxo-4-hexenoyl-CoA and all following methylated intermediates were not able to enter the cycle any more. Obviously, the region of Bmt polyketide synthase responsible for this latter part of the biosynthetic pathway is inaccessible for externally supplied coenzyme A thioesters. Butyryl-CoA was recognized by Bmt polyketide synthase with an efficiency comparable to that of crotonyl-CoA and processed to 3-hydroxy-4-methyloctanoyl-CoA, the saturated analog of the natural basic assembly product, indicating a relaxed specificity of Bmt polyketide synthase with respect to the starter unit.

The fourth EF-hand of calmodulin and its helix-loop-helix components: impact on calcium binding and enzyme activation

CaM (4 cTnC) is a calmodulin--cardiac troponin C chimeric protein containing the first, second, and third calcium-binding EF-hands of calmodulin (CaM) and the fourth EF-hand of cardiac troponin C (cTnC) [George, S.E., Su, Z., Fan, D., & Means, A.R. (1993) J. Biol. Chem. 268, 25213-25220]. CaM (4 cTnC) showed 2-fold-enhanced carboxy-terminal Ca2+ affinity relative to CaM and also exhibited impaired activation of the CaM-regulated enzymes smooth muscle myosin light chain kinase (smMLCK), neuronal nitric oxide synthase (nNOS), and phosphodiesterase (PDE). To investigate the molecular basis for these effects, we constructed (1) additional chimeras, replacing most of CaM helix 7, Ca2+-binding loop 4, and helix 8 with the corresponding helices and loops of cTnC; and (2) point mutants in the fourth EF-hand of CaM. Replacement of CaM's fourth loop with the corresponding loop of cTnC enhanced Ca2+ affinity by over 3-fold through an increase in the Ca2+ on rate and also reduced cooperativity of Ca2+ binding. In contrast, substitution of CaM helix 7 or 8 modestly decreased Ca2+ affinity by increasing the Ca2+ off rate, without impairment of cooperativity. All three of the helix and loop chimeras fully activated PDE, with minor shifts in Kact. CaM (helix 7 cTnC) showed a significantly impaired ability to activate smMLCK and nNOS, whereas the other two chimeras retained about 80% of the maximal smMLCK and nNOS activation observed with CaM.

[A study of HIA-DR antigen expression in nasopharyngeal carcinoma and its relation with clinical pathology and prognosis]

In order to clarify the relationship between HLA-DR antigen expression of nasopharyngeal carcinoma (NPC) and the clinicopathology and prognosis of NPC, immunohistochemical studies on HLA-DR antigen expression in 77 NPC cases were performed. The results showed that the positive rate of HLA-DR was 44.2% in this series. Non-neoplastic epithelium did not express this antigen. A close association was found between expression of HLA-DR antigen and the clinical staging of NPC. The positive rate of HLA-DR gradually decreased with tumor progression, showing a remarkable difference among tumors in different clinical stages (P < 0.05). Analysis of patient survival demonstrated that the prognosis of NPC patients with HLA-DR expression was significantly better than those without (P < 0.01). The above results give support to the possibility of immunomodulation of tumors.

[Dynamic assay of oleanolic acid in Aralia taibaiensis Z. Z. Wang et H. C. Zheng]

The dynamic assay on oleanolic acid (OA) in Aralia taibaiensis shows that the plant has a higher OA level. The level in root cortex is 4.74%-10.81% and peak stages are mid-May to late June and late August to mid-September the level in stem barks is 3.59%-12.06% and peak period is between mid-May and late July, the level in leaves increases throughout the life time ranging from 2.41% to 6.66% and peak level is 6.66% around mid-September.

[Studies on Cnidium fruits by stereological method and computer image analysis]

The fruits, pollen grains, vascular bundles, stomata and endosperm cells of 4 Cnidium species were studied and determined by stereological method and computer image analysis technique. Statistical data were presented. In the volume of fruit and the area of vascular bundle, Cnidium dahuricum is the biggest, then C. salinum, C. japonicum and C. monnieri successively. In the volume of pollen grain,C. salinum is the biggest, followed by C. dahuricum, C. japonicum and C. monnieri in succession. In the volume of endosperm cell, C. dahuricum is also the biggest, and then C. japonicum, C. salinum and C. monnieri in order.

The calmodulin-nitric oxide synthase interaction. Critical role of the calmodulin latch domain in enzyme activation

The neuronal isoform of nitric oxide synthase (nNOS) requires calmodulin for nitric oxide producing activity. Calmodulin functions as a molecular switch, allowing electron transport from the carboxyl-terminal reductase domain of nitric oxide synthase to its heme-containing amino-terminal domain. Available evidence suggests that calmodulin binds to a site between the two domains of nNOS, but it is not known how calmodulin then executes its switch function. To study the calmodulin-nNOS interaction, we created a series of chimeras between calmodulin and cardiac troponin C (cTnC, a homologue of calmodulin that does not activate nNOS). Although a few chimeras showed good ability to activate nNOS, most failed to activate. A subset of the inactive chimeras retained the ability to bind to nNOS and therefore functioned as potent competitive inhibitors of nNOS activation by calmodulin (CaM). The observed inhibition was additive with the arginine antagonists NG-monomethyl-L-arginine and 7-nitroindazole, indicating a distinct and independent mechanism of nNOS inhibition. To localize the calmodulin residues that account for impaired activation in the inhibitory CaM-cTnC chimeras, we conducted a detailed mutagenesis study, replacing CaM subdomains and individual amino acid residues with the corresponding residues from cTnC. This revealed that mutations in CaM helices 2 and 6 (its latch domain) have a disproportionate negative effect on nNOS activation. Thus, our evidence suggests that the CaM latch domain plays a critical role in its molecular switch function.

Anti-CD3:anti-IL-2 receptor-bispecific mAb-mediated immunomodulation. Low systemic toxicity, differential effect on lymphoid tissue, and inhibition of cell-mediated hypersensitivity

An anti-CD3:anti-CD25 (CD3,25) bispecific mAb was developed with the objective of combining the advantages of the parent anti-CD3 and anti-CD25 mAbs. The in vivo effects of the CD3,25 were examined in comparison to the parent Abs. The CD3,25 was well tolerated in vivo, in contrast to the parent anti-CD3 mAb, which induced systemic toxicity in recipient animals. Anti-CD3 mAb induced cell death, lymphoblast formation, and T cell activation in peripheral lymphoid organs; these were observed to a lesser extent in CD3,25-treated animals. In the thymus, anti-CD3 caused a progressive depletion of the CD4+ CD8+ "double positive" thymocytes, which was not seen in CD3,25-treated animals. This finding suggests that monovalent CD3 binding is insufficient to induce thymocyte apoptosis. Animals treated with a combination of anti-CD3 and anti-CD25 mAbs demonstrated changes in the lymphoid organs that were similar to anti-CD3-treated mice. This finding demonstrates that the effect of the CD3,25 is different than the sum of the parent Abs and suggests that the bispecific nature of the CD3,25 results in a reagent with unique immunomodulatory properties. The functional efficacy of the CD3,25 was assessed in a murine model of delayed-type hypersensitivity. The CD3,25 was as effective as the anti-CD3 mAb in inhibiting the delayed-type hypersensitivity reaction and was more effective than the parent anti-CD25 mAb. These data demonstrate that appropriately designed bispecific mAbs can be used as effective immunosuppressive agents with low systemic toxicity.

Anti-CD3:anti-IL-2 receptor-bispecific mAb-mediated immunomodulation. Low systemic toxicity, differential effect on lymphoid tissue, and inhibition of cell-mediated hypersensitivity

An anti-CD3:anti-CD25 (CD3,25) bispecific mAb was developed with the objective of combining the advantages of the parent anti-CD3 and anti-CD25 mAbs. The in vivo effects of the CD3,25 were examined in comparison to the parent Abs. The CD3,25 was well tolerated in vivo, in contrast to the parent anti-CD3 mAb, which induced systemic toxicity in recipient animals. Anti-CD3 mAb induced cell death, lymphoblast formation, and T cell activation in peripheral lymphoid organs; these were observed to a lesser extent in CD3,25-treated animals. In the thymus, anti-CD3 caused a progressive depletion of the CD4+ CD8+ "double positive" thymocytes, which was not seen in CD3,25-treated animals. This finding suggests that monovalent CD3 binding is insufficient to induce thymocyte apoptosis. Animals treated with a combination of anti-CD3 and anti-CD25 mAbs demonstrated changes in the lymphoid organs that were similar to anti-CD3-treated mice. This finding demonstrates that the effect of the CD3,25 is different than the sum of the parent Abs and suggests that the bispecific nature of the CD3,25 results in a reagent with unique immunomodulatory properties. The functional efficacy of the CD3,25 was assessed in a murine model of delayed-type hypersensitivity. The CD3,25 was as effective as the anti-CD3 mAb in inhibiting the delayed-type hypersensitivity reaction and was more effective than the parent anti-CD25 mAb. These data demonstrate that appropriately designed bispecific mAbs can be used as effective immunosuppressive agents with low systemic toxicity.

[Textual study and resource investigation on traditional Chinese drugs duhuo, jiuyanduhuo and qianghuo]

By means of Bencaological study on traditional Chinese drugs Duhuo, Jiuyanduhuo and Qianghuo, it has been found out that the Duhuo recorded in earlier Bencao works should be Qianghuo, and Duhuo was first used medically in the South-North Dynasty period, whereas Jiuy-anduhuo's medical use started in the Ming Dynasty. Resources of the three drugs were investigated and their main species were found out.