Effect of CCK-8 on audiogenic epileptic seizure in P77PMC rats

P77PMC rat is a breed of rat with congenital audiogenic seizure(AS). AS attacks were suppressed by cholecystokinin octapeptide (CCK-8) injected intraperitoneally (i.p.) at a dose of 50 micrograms/kg, but not at 25 micrograms/kg. Radioimmunoassay study showed that the CCK-8 immunoreactivity (IR) in the cerebrocortex and hippocampus is much lower in P77PMC rats than that of Wistar rats. The results suggest that a low cerebral content of CCK-8 may account for the high susceptibility of audiogenic seizure in P77PMC rats.

A synthetic C22 carotenoid inhibits carcinogen-induced neoplastic transformation and enhances gap junctional communication

In 10T1/2 cells several dietary carotenoids have previously been shown to be capable of inhibiting carcinogen-induced neoplastic transformation. Two synthetic novel compounds, a C22 carotenoid, C22-polyene-tetrone-diacetal, and a C28 carotenoid, C28-polyene-tetrone, have now been tested in this system. The C22 compound was active in completely inhibiting 3-methylcholanthrene-induced transformation at 10(-5) M when added during the post-initiation phase of carcinogenesis. Gap junctional intercellular communication was strongly upregulated at this concentration. This activity has previously been shown to be highly correlated with, and has been proposed to be mechanistically linked to, inhibition of transformation by carotenoids in 10T1/2 cells. In contrast, the C28 compound, previously reported to be more active as a singlet oxygen quencher than C22, did not demonstrate activity in 10T1/2 cells in either assay system. This lack of activity was not due to chemical instability or lack of cellular uptake: the C28 compound was more stable in cell culture medium over 7 days and achieved higher cellular levels than the C22 compound (5 x 10(-11) mol/10(6) cells versus 0.5 x 10(-11) mol/10(6) cells). The activity of the C22 compound was not due to toxicity, since transformation occurred in carcinogen-treated cultures after its removal; neither was it due to antiproliferative effects on transformed cells, since the C22 compound did not prevent focus formation by transformed cells in reconstruction experiments. The demonstration that synthetic carotenoids possess biological activities comparable to the most potent naturally occurring compounds suggest that rational synthesis of compounds with improved pharmacological properties should be possible.

Purification and characterization of a DNA-binding heterodimer of 52 and 100 kDa from HeLa cells

In studies of protein binding to the upstream region of the human proliferation-associated antigen p120 gene, a heterodimer of 52 and 100 kDa proteins was purified from HeLa cells. A 1:1 ratio of p52 and p100 was constant throughout the purification. The heterodimer was localized to cell nuclei, as shown by immunofluorescence. The pI values of the p52 and p100 were 7.8 and 8.6 respectively. The peptide sequences obtained for p52 (QSNKTFNLEKQNHTPRKKHQ and PLRGKQLRVRFAAHSASLTVR) and for p100 (PGGPKPGGGPGLSTPGGHPKPPHRGGGEPPRGRQ and GPGPGQSGPKPPIPPPPPHQQ) were not found in the computer databanks. One p52 peptide sequence, PLRGKQLRVRFA, shows considerable sequence similarity to a conserved motif in topoisomerase II of multiple species. The p52/100 heterodimer bound to different DNA probes. The binding was competed by poly(dI-dC), sonicated salmon sperm DNA, and circular or linearized plasmid DNA. The optimal DNA binding for the heterodimer was at pH 7-9 with low salt. The DNA-binding subunit of the heterodimer was the p100 polypeptide, as shown by u.v.-cross-linking assays and Southwestern blots.

[Effects of microiontophoretically applied ACH and atropine on the electric activities of neurons in nucleus parafascicularis of thalamus in rats]

The effects of acetylcholine (ACh) and atropine on the electric activities of neurons of nucleus parafascicularis thalami (Pf) were observed in anesthetized rats with multimicropipette technique and iontophoresis. It was found that the spontaneous and pain-induced discharges of the Pf neurons were excited and some of non-nociceptive neurons became sensitive to nociceptive stimulation with microiontophoretically applied ACh, while microiontophoretically applied atropine could diminish the spontaneous and pain-induced discharges of the Pf neurons. The effects of ACh above could be blocked by microiontophoretically applied atropine. The results show that ACh may have excitatory effects on the electric activity of the Pf neurons by M-receptor.

[A methodological study of PC IOL implantation in eyes partially or totally devoid of the posterior lens capsule]

From September 1987 to June 1991, 57 patients aged 3 to 41 years were implanted PC IOL in 57 eyes partially or totally devoid of the posterior lens capsule. The postoperative visual acuity ranged from 0.2 to 1.5 during a follow-up of 3 to 48 months. The authors' operating procedures and indications are discussed.

Carotenoids up-regulate connexin43 gene expression independent of their provitamin A or antioxidant properties

Epidemiological evidence and studies in whole animals and cell culture have indicated that carotenoids have cancer chemopreventive action. In mouse C3H10T1/2 cells, this activity is highly correlated with the ability of carotenoids to up-regulate gap junctional intercellular communication. Here, we report that in mouse cells, carotenoids increase the expression of connexin43, a gene that encodes a major gap junction protein. This effect appears unrelated to their provitamin A or antioxidant properties, since carotenoids with and without provitamin A activity increased levels of connexin43 mRNA and protein, whereas the antioxidants methyl-bixin and alpha-tocopherol were inactive. Moreover, the active carotenoid canthaxanthin did not induce the vitamin A-inducible gene retinoic acid receptor-beta. Connexin43 is the first carotenoid-inducible gene described in mammals. By indicating an additional pathway through which carotenoids function, these data provide a mechanistic basis for cancer chemoprevention by carotenoids and may lead to a re-evaluation of carotenoid physiology.

Suppression of audiogenic epileptic seizures by intracerebral injection of a CCK gene vector

P77PMC rat is a breed of rat with congenital audiogenic seizure (AS). AS attacks could be suppressed by cholecystokinin octapeptide (CCK-8) injected intracerebroventricularly (i.c.v.). In the present study we made i.c.v. injection of plasmid pSV2-beta Gal or pSV2-CCK encapsulated with lipofectin. Expression of pSV2-beta Gal in brain occurred from d 1 to d 14, with maximal expression at d 3 and d 4. After i.c.v. injection of pSV2-CCK plasmid, the AS of the P77PMC rats was markedly reduced, which was most obvious at d 3 and d 4. The time course of the AS repression was almost identical with that of pSV2-beta Gal expression. The results suggest that the repression of the AS in P77PMC rats is accounted for by the expression of foreign CCK gene in brain tissue.

Inhibition of cellular transformation by triphenylmethane: a novel chemopreventive agent

Triphenylmethane (TPM) was found to inhibit 3-methyl-cholanthrene-induced neoplastic transformation of 10T1/2 cells in a dose-dependent manner (ED50 = 2.8 microM). This activity was independent of any effect on intercellular communication and did not appear to be directly related to the general antioxidant properties of TPM as measured by cellular thiobarbituric acid-reactive substances. Triphenylmethanol (TPMOL) and diphenylmethane also inhibited transformation (ED50 = 6.9 and 90 microM respectively). TPM had no effect on the proliferation of exponentially growing cells. At higher concentrations TPM and its analogues enhanced plating efficiency of cells indicating no significant toxicity for these compounds at levels up to 50 microM. The inhibitory effects of TPM on transformation were reversible when TPM was removed from the medium. While TPM had no effect on the growth of fully transformed cell lines, it was able to inhibit the growth of 1/3 neoplastic foci in the presence (but not absence) of 10T1/2 cells. TPM was found to stimulate protein kinase C (PKC) activity for both crude C3H10T1/2 cytosolic PKC and purified PKC obtained from rat brain. The ability of TPM to stimulate PKC activity appeared to be dependent on [CaCl2] and the order of reagent addition in the assay. Tamoxifen, a structurally related compound to TPM, was also found to enhance PKC activity over the same concentration range but was less potent than TPM. The biological effects of TPM and related compounds indicate that they function in a manner distinct from other highly unsaturated transformation inhibitors such as carotenoids and retinoids. The inability of triphenylene to inhibit transformation suggests that a reactive methyl carbon may be essential for activity.

Tuberculosis control programme in Beijing

Since 1978 a new tuberculosis control programme based on modern concepts has been started in Beijing. The main goals of the programme were: (1) To prioritize the control of sources of infection; (2) to instigate fully supervised treatment (FST) for new smear-positive patients; (3) to extend services to the rural areas. A four-level network of tuberculosis control services has been organized both in urban and rural areas. Tuberculosis control has been integrated into rural primary health care. Coverage of FST among new smear-positive cases increased to 93% in 1990. A standard regimen, 1HS/11H2S2 has been used for initial treatment. A reserve regimen of RFP and EMB was added to those who failed to convert in 6 months. Since 1988 a 6-month intermittent short-course regimen has been introduced as standard regimen. Case-finding has been intensified since 1980 through symptomatics. Control of chronic excreters was achieved through FST of new smear-positive cases and fully supervised retreatment of old chronic cases. The new tuberculosis control programme has proved highly successful in controlling sources of infection. The prevalence of smear-positive pulmonary tuberculosis in Beijing during the national surveys in 1979, 1984-1985 and 1990 was 127, 56 and 16 per 100,000 respectively. The average annual reduction rate was 17%. This successful experiment has been recognized as a model for the whole country.

Carotenoids enhance gap junctional communication and inhibit lipid peroxidation in C3H/10T1/2 cells: relationship to their cancer chemopreventive action

We have previously demonstrated that diverse carotenoids inhibit chemically induced neoplastic transformation in 10T1/2 cells. To address their mechanism of action, the effects of six diverse carotenoids, with or without provitamin A activity, on gap junctional communication and lipid peroxidation have been investigated. beta-Carotene, canthaxanthin, lutein, lycopene and alpha-carotene increased gap junctional intercellular communication in a dose-dependent manner in the above order of potency, whereas m-bixin was inactive at concentrations up to 10(-5) M. alpha-Tocopherol, a potent chain-breaking antioxidant, caused a marginal enhancement of junctional communication. The enhancement of junctional communication by diverse carotenoids showed a strong statistical correlation with their previously determined ability to inhibit methylcholanthrene-induced neoplastic transformation (r = -0.75). All carotenoids tested inhibited lipid peroxidation, but with differing potencies. alpha-Tocopherol was the most active inhibitor followed by m-bixin. The capacity of carotenoids or alpha-tocopherol to inhibit lipid peroxidation was neither consistent with their ability to inhibit neoplastic transformation (r = 0.30) nor to increase junctional communication (r = 0.12). Since junctional communication appears to play an important role in cell growth control and carcinogenesis, we propose that in this system carotenoid-enhanced intercellular communication provides a mechanistic basis for the cancer chemopreventive action of carotenoids. These data also imply that carotenoids function in a manner analogous to retinoids in the 10T1/2 assay system. Interestingly this activity appears independent of their provitamin A status.

Dot-immunobinding assay (DIBA) with integral Plasmodium falciparum as antigen in immuno-diagnosis of falciparum malaria

Among the available immuno-diagnostic methods of parasitoses, dot-immunobinding assay (DIBA) has been proved to be promising for its high sensitivity and specificity, easy performance, lack of need of special equipment, and consequently its practical usage in field work. In previously reported tests, soluble antigen was used, thus a sonicator and an ultracentrifuge were required to produce the antigen. This paper reports the application of integral P. falciparum as antigen in DIBA to detect antibodies in falciparum malaria cases. Of 52 sera from falciparum malaria patients tested, 49 (94.2%) showed positive reactions, which was similar to the result using soluble antigen in DIBA (96.2%) and was higher than that in IFA (86.5%) and ELISA (80.8%). No false positive was revealed in 48 control sera from healthy individuals and sera from visceral leishmaniasis, paragonimiasis, fasciolopsiasis and schistosomiasis patients.

[Determination of the contents of mineral elements in the soil where the jinin big-wild ginseng grows]

The element contents in the soil where the Jilin Big-Wild Ginseng grows were determined with plasma emission spectrometry. 23 elements in the soil were found, of which 12 are macro and trace elements indispensable to Ginseng growth. This study provides a scientific basis for selecting suitable soil for planting wild ginseng, or for creating optimum soil conditions for the bumper harvest and high quality of Ginseng.

The control of chronic infectious patients with pulmonary tuberculosis in a rural area of China

The aim of this study was to reduce the prevalence of chronic infectious cases (CIC) in a rural area of China by fully supervised chemotherapy of newly diagnosed smear-positive cases and by reducing the number of existing old CIC through fully supervised retreatment. From 1980 to 1985, 83.3% of 1828 new, smear-positive cases were given fully supervised chemotherapy. In 1980, 95.2% of 565 old CIC started fully supervised retreatment. The prevalence of CIC had dropped from 40.5/100,000 in 1980 to 6.7/100,000 by the end of 1986.

A comparison of the primary structures of lactate dehydrogenase isozymes M4 from giant panda, red panda, black bear and dog

Lactate dehydrogenase isozymes M4 have been isolated and purified from red panda (Ailurus fulgens), black bear (Selenarctos thibetanus) and dog (Canis familiars) by affinity chromatography and compared with that from giant panda (Ailuropoda melanoleuca). Experimental results have shown that the N-termini, C-termini and the molecular weights of LDH-M subunits of red panda, black bear and dog are the same as those of the LDH-M subunit of giant panda. Analysis and comparison of HPLC peptide maps from the tryptic digests of the isozymes of red panda, black bear and dog have shown that most of their peptide fragments had the same retention time and amino acid composition as the corresponding peptide fragments from giant panda. Fragments with different retention times and/or amino acid compositions were sequenced. Careful examination of those variant amino acid residues demonstrated clearly that the primary structure of giant panda LDH-M subunit is unique and it appears that the giant panda might be classified as an independent family.

The primary structure of the lactate dehydrogenase isozyme M4 from giant panda

The amino acid sequences of tryptic, chymotryptic and cyanogen bromide cleavage peptides of the lactate dehydrogenase isozyme M4 from giant panda have been determined. Based on the overlapping peptides and by a comparison with the known sequence of porcine lactate dehydrogenase isozyme M subunit, the complete primary structure of the giant panda lactate dehydrogenase isozyme M subunit has been established. The polypeptide chain of giant panda lactate dehydrogenase isozyme M subunit consists of 331 amino acid residues. There is a variance of 17 amino acid residues between the porcine and the giant panda lactate dehydrogenase isozyme M subunits. Most of the variable residues are substitutions by chemically similar amino acids and take place at residues not related to the active center of the enzyme.

Supervised intermittent chemotherapy for pulmonary tuberculosis in a rural area of China

In order to ensure regularity of ambulatory treatment of new cases of pulmonary tuberculosis, a fully supervised intermittent chemotherapy regimen was tried in two rural counties of Beijing. The bare-foot doctors of the village health co-operatives were designated to administer and supervise treatment. The regimen consisted of isoniazid and streptomycin daily for 1 month, then every 3 days for 5 months and then every 5 days for a total of 12 or 18 months. For smear-negative cases the daily phase was omitted. The compliance rate among 229 patients in 1 year was 99.4%. The sputum conversion rate among 104 cases harbouring sensitive bacilli was 95.2%. Discontinuation of the regimen due to side-effects as necessary in 3 cases (1.3%). Since 1979, this treatment programme has been adopted in the whole rural area of Beijing, and the coverage rate among newly diagnosed smear-positive cases in 1983 reached 90%. A reserve regimen consisting of rifampicin and ethambutol for patients who do not convert their sputum after 6 months of treatment with isoniazid and streptomycin was added. The overall conversion rate achieved in 1981 was 97.8%. The average overall cost of drugs for each patient treated in this treatment programme was 49 yuan (RMB), about $24.00 U.S.