Chromosome mapping using polymerase chain reaction on somatic cell hybrids

DNA polymerase chain reaction (PCR) was used to detect specific human sequences in human-mouse somatic hybrids. As compared with classic Southern blotting, this technique appeared to be more sensitive and less time-consuming for gene mapping.

[Inhibitory effect of yunfujing on vestibular stimulative response in rats and volunteers]

Fifty female rats were used in the experiment. With rotation model, Yunfujing was shown to inhibit nystagmic response of rats. The inhibitory effect was 20-30 times stronger than that of Mihuanjun. In Coriolis test, the tolerance time of vestibular stimulative response was taken as a parameter for judging drug efficacy in 32 male volunteers. Following oral administration of Yunfujing at a dose of 400 mg, the tolerance time of vestibular stimulative response was prolonged significantly from 411.34 to 759.63 s. In the mean time, no changes of blood pressure and pulse were observed in the treated group.

[Study of characteristics of monoclonal antibody against substance P]

Cross-reaction of a rat monoclonal antibody (BTP-1) against seventeen substance P analogues was studied. The antibody was of IgG type and related to the carboxyl terminal of substance P, especially methionyl in the terminal, but did not depend on the strength of antagonistic effects of these analogues. It did not show cross-reaction with the following nine peptides: glucagon, endorphin, angiotensin I, II, leucine-enkephalin, methionine-enkephalin, bradykinin, oxytocin and dernorthin, indicating its high specificity to substance P. By means of immuno-enzyme histochemical method, it was shown that stained nerve fibers were located in the gelaliternous substance of Rolando, interpeduncular nucleus, substantia nigra and nerve cell bodies in the vestibular nucleus, lateral tegmental nucleus of mesencephalon and ventral region of third ventricle.

[Effects of cholecystokinin, gastrin and proglumide on bile secretion in rats]

The aim of this study is to observe the effects of pentagastrin (P-Gas), CCK-8 and proglumide (PGM), which were used solely or in combination on choleresis in rats prepared with neck vein and hepatic-bile duct intubation. The results indicate that: 1) P-Gas does not provide cholecystic effect; 2) CCK-8 has a little stimulating effect on bile flow and output of bicarbonate; 3) PGM increases the bile flow and the outputs of biliary bicarbonate and chloride significantly, but it can not increase the bile acid output; 4) after administration of CCK-8 2.3 micrograms/(kg.h) iv infusion and PGM 200 mg ig in combination the outputs of bile flow, bicarbonates and chloride were greater than to PGM given alone, but after P-Gas 2 micrograms/(kg.h) was used together with PGM the outputs were less than to PGM given alone. The results suggest that PGM has a remarkable effect of choleresis and its mechanism may be attributed to bile acid independent fraction, while CCK-8 was only a weaker stimulant and P-Gas can not modify the bile flow and bile components. In addition, there may be a synergism effect between PGM and CCK-8 and an antagonist suppression between PGM and P-Gas on choleresis in the rat.

[Glucocorticoid receptors on human peripheral mononuclear and polymorphonuclear leucocytes: changes in patients with yang-deficiency]

It was found that, in former works, the glucocorticoid receptors (GCR) on peripheral mixed leucocytes in patients with Yang-deficiency were decreased. In this work, the mixed leucocytes were further separated into mononuclear (MNL) and polymorphonuclear (PML) leucocytes, and GCR were determined in each part of leucocytes. GCR on MNL and PML in 6 Yang deficient patients were 3473 +/- 413 and 4433 +/- 651 sites/cell respectively, statistically significant from the normal control group (4462 +/- 962 and 5622 +/- 782 sites/cell respectively, P less than 0.05). GCR on MNL, PML and mixed leucocytes in 5 patients were determined simultaneously, and all lowered from the control group. The results were 3369 +/- 370, 4986 +/- 419 and 4524 +/- 852 sites/cell respectively, with the lowest GCR on MNL and highest on PML.

[Poliovirus separation by centrifugation in Percoll isopycnic gradients]

Centrifugation in Percoll isopycnic gradients is reported as effective and simple method for separation and purification of polioviruses. By this method, not only may one separate poliovirus from simian virus 40 (SV40), but also may separate empty virions from solid virions of poliovirus. The bouyant density in Percoll of solid virion of poliovirus, empty virion of poliovirus and SV40 are 1.084, 1.051 and 1.13, respectively. The recovery rate of virus is about 65%.

[Effect of wuwei chongji on the mechanical activity of the stomach of SD rats in vivo]

The effect of Wuwei Chongji on the mechanical activity of stomach of SD rats was studied using fixed point method. The experimental results showed that Wuwei Chongji increased the amplitude and frequency of contraction of stomach in rats, and was able to adjust the high and low tension of contraction of stomach. The contraction of the stomach was not influenced by Natrii Chloridi (0.9%) at the same dose.

Early events of RNA polymerase II transcription initiation

We have investigated the earliest stages of assembly of an RNA polymerase II transcription complex. General transcription factors from HeLa cells were partially purified and assayed using the adenovirus-2 major late promoter. Preincubation of either all the transcription factors (TF) with the DNA or only the subset consisting of TFIIA, TFIID, and DNA overcame the 15-20 min lag normally observed. The kinetics demonstrate that TFIIA first interacts with the template over a 5 min. period, and then TFIID interacts with the IIA:DNA complex over a 2 min. period. The remainder of the necessary transcription factors then interact with the IIA:IID:DNA complex. There are apparently interactions between IIA and IID, as a pre-incubation of these factors (without DNA) overcomes the lag period. Both IIA:DNA and IIA:DNA:IID interactions are temperature sensitive, resulting in slower kinetics at 0 degree C. Thus, the kinetics of transcription involve activation processes in addition to DNA binding.

Mortality and fertility: how large is the direct child replacement effect in China?

"The direct child replacement effect, that is the extent to which parents will have a child to replace one that died, was estime d by Olsen's method in China, using microdata from a sample survey of 4785 ever-married women in Hebei province taken in 1985. Olsen's method corrects for bias in the ordinary least squares estimate and uses mortality rates as an instrumental variable. Data for all age groups were pooled. Estimates of the direct replacement effect before and after correction for bias were 0.836 and 0.556, showing that over half of child deaths were replaced. The instrumental variable estimate produced a result of 0.614, similar to 0.613, computed by considering p1 to be random. A computation without instrumental variables yielded 0.774. The results showed that this method for calculating the direct replacement effect works well with these data because several of the alternative methods gave close estimates. There appears to be little family specific variation in child mortality rates, pointing out the effectiveness of Chinese primary health care. The direct replacement effect of about 0.6 is, however about 3 times that found by Olsen in Colombia and Malaysia, and close to the theoretical maximum. The reason for such a high value may be the small family size in China, where death of a child is more likely to provoke a response. Or it might suggest that severe government policy causes couples to attempt to have another child. Policy implications in this setting are that rather than make more contraceptives available, or improve infant survival, Chinese policymakers should make a small family size attractive, e.g., by improving education or pensions.

Socioeconomic determinants of fertility in China: a microeconometric analysis

"This paper reports the first set of estimates of the socioeconomic determinants of fertility in China using micro-data available from China's 1985 In-Depth Fertility Survey. Based on existing microeconomic theories of fertility, an econometric model was specified and estimated. The results indicate that even after age, marriage duration and child mortality are taken into account, education level of the woman, occupational status of the husband, the place of former and current residence, sex preference for boys, durable goods ownership, and family structure affect fertility."

Sodium and calcium currents in action potentials of rat somatotrophs: their possible functions in growth hormone secretion

We report that both Na+ and Ca2+ currents are involved in the action potentials and in the hormone release from rat somatotrophs in primary culture. Single somatotrophs were identified by reverse hemolytic plaque assay (RHPA) and transmembrane voltage and currents were recorded using the whole-cell mode of the patch-clamp technique. Somatotrophs displayed a mean resting potential of -80mV and an average input resistance of 5.7G omega. Most of the cells showed spontaneous or evoked action potentials. Single action potentials or the initial spike in a burst were characterized by their high amplitude and short duration. Tetrodotoxin (TTX, 1 microM) blocked single action potentials and the initial spikes in a burst, whereas action potentials of long duration and low amplitude persisted. Cobalt (2 mM) plus TTX (1 microM) blocked all the action potentials. Voltage-clamp experiments confirmed the presence of both a TTX-sensitive Na+ current and Co2(+)-sensitive Ca2+ currents. TTX or Na(+)-free medium slightly decreased the basal release of GH but did not markedly modify hGRF-stimulated GH release. However, Co2+ (2 mM), which partially decreased the basal release, totally blocked hGRF-stimulated release. We conclude that (1) Na+ currents which initiate rapid action potentials may participate in spontaneous GH release; (2) Ca2+ currents, which give rise to long duration action potentials and membrane voltage fluctuation, are probably involved in both basal and hGRF-stimulated GH releases.

The evolution of B-cell clones

This chapter identifies three forms of B-cell memory: (a) B blasts which characterize the established stage of the follicular response to TD antigens, (b) recirculating memory B cells, and (c) non-recirculating memory B cells of the marginal zones of the spleen and equivalent areas of other secondary lymphoid organs. The follicular B blasts show sustained proliferation driven by small amounts of antigen bound to FDCs. The probable relationships between these cells is summarized diagrammatically in Fig. 4. It is probable that follicular B blasts generate both the recirculating and marginal zone memory cells. The chapter by Gray and Leanderson in this volume cites data which indicate that the recirculating memory pool is not sustained for more than a few weeks in the absence of antigen. Data leading to the same conclusion for marginal zone memory B cells is set out in Sect. 5.1 of this chapter. Marginal zone memory B cells do not appear to move spontaneously to follicles for periodic renewal. They will only leave the marginal zone if a fresh supply of antigen reaches them in that site. Recirculating B cells are able to respond to antigen already held on FDCs. It is not known if they are able to displace B blasts of equivalent affinity for antigen which already occupy antigen-holding sites on FDCs. This could be a mechanism by which B blasts with high antigen affinity produced in one follicle could displace blasts of lower affinity in other follicles. Little is known of the factors which regulate the numbers of marginal zone and recirculating follicular memory B cells. In responses to hapten-protein conjugates, hapten-binding cells may approach 10% of marginal zone B cells but comprise well under 1% of recirculating follicular cells. The numbers of these memory cells do not increase if the recirculating pool of lymphocytes is depleted, indicating that the factors which regulate the number of memory B cells are independent of those which regulate the total size of the recirculating B-cell pool. A depleted peripheral B-cell pool can only be fully reconstituted by recruitment of newly produced virgin B cells. Data cited in Sect. 5.2 support the concept that this recruitment is at least partially independent of antigen-driven B-cell proliferation. Consequently, substantial proportions of the peripheral B-cell pools are likely to be either virgin cells or cells which have been recruited by antigen or anti-idiotype without entering cell cycle.(ABSTRACT TRUNCATED AT 400 WORDS)

Rapid cryopreservation of sheep embryos by direct transfer into liquid nitrogen vapour at -180 degrees C

The in vitro survival of control and rapidly cryopreserved sheep embryos was examined as a function of the duration of exposure to a vitrification medium (25% glycerol + 25% propylene glycol). Embryos in late morula to late blastocyst stages were permeated by a mixture of 10% glycerol + 20% propylene glycol for 10 min at 18-23 degrees C and then exposed to the vitrification medium for 0.5, 1, 2 or 4 min at 18-23 or 4-12 degrees C. The cryoprotectants were removed without cryopreservation (control embryos) or after rapid cryopreservation by direct transfer into liquid nitrogen vapour at -180 degrees C. The duration of exposure to the vitrification medium at 18-23 degrees C affected the in vitro survival rate of control embryos (P = 0.06) but had no effect on the survival of rapidly cryopreserved embryos. However, at 4-12 degrees C the duration of exposure affected the survival of cryopreserved embryos (0.5 min: 64%, 18/28; 1-4 min: 43%, 34/80; P = 0.074). Overall, the in vitro survival rate of control and cryopreserved embryos increased with advancing development from late morulae (36%) to late blastocysts (70%). The in vivo survival of embryos that had been exposed to the vitrification medium for 0.5 min at 4-12 degrees C and then vitrified was tested. The rate of development to term was 11% (4/35) for late morulae or early blastocysts and 32% (6/19; P greater than 0.1) for blastocysts to hatching blastocysts. These results showed that sheep embryos can be successfully cryopreserved by a simple, rapid procedure.

Molecular analysis of the isochromosome 12P in the Pallister-Killian syndrome. Construction of a mouse-human hybrid cell line containing an i(12p) as the sole human chromosome

An iso 12p chromosome from a patient with Pallister-Killian syndrome was successfully transferred into a mouse background by microcell-mediated chromosome transfer. The presence of the i(12p) chromosome was confirmed by karyotyping and by Southern blotting using five 12p and seven 12q probes. The isochromosome nature of the marker chromosome was confirmed by co-hydridization of a 12p probe with a 12q and an 8q probe. This cell line should be a valuable tool for physical mapping of 12p-derived DNA fragments; at the same time, it confirms the identity of the extra chromosome in the Pallister-Killian syndrome as i(12p).

Drug inhibitors of RNA polymerase II transcription

Transcription by RNA polymerase II occurs after formation of a transcription complex. This complex is assembled in stages by the interaction of transcription factors with the template and/or with each other. We report on the ability of six drugs to inhibit the assembly of the RNA polymerase II transcription complex. Assembly of the complex on the adenovirus major late promoter requires several transcription factors. The normal assembly process requires that the DNA first interact with TFIIA, then with TFIID, and finally with at least four additional transcription factors (one of which is RNA polymerase II). We observed that streptolydigin (10 micrograms/ml) inhibits association of ILA and IID, and at higher concentrations (100 micrograms/ml) inhibits that IIA/IID complex from binding to DNA. Streptovaricin (100 micrograms/ml) appears to inhibit the IIA/IID interaction with DNA and prevents reinitiation (at 500 micrograms/ml). Adriamycin (1 microgram/ml) inhibits the interaction of TFIID with the IIA/DNA complex and inhibits an additional event immediately prior to, or during, elongation. Daunorubicin may be an elongation inhibitor. Heparin at 10 micrograms/ml inhibits further assembly after the IIA/IID/DNA complex has formed, and at 100 micrograms/ml also inhibits a late event in the assembly process and blocks reinitiation. Rifamycin AF/013 (100 micrograms/ml) inhibits the early events necessary to form the IIA/IID/DNA complex and (at 10 micrograms/ml) an assembly event following formation of the IIA/IID/DNA complex. Therefore, these compounds should be useful as probes for further examination of the assembly process.

A cluster of alpha 2-macroglobulin-related genes (alpha 2 M) on human chromosome 12p: cloning of the pregnancy-zone protein gene and an alpha 2M pseudogene

The characterization of two alpha 2-macroglobulin (alpha 2M)-related genomic clones, isolated from two human genomic libraries by use of alpha 2M cDNA [Kan et al., Proc. Natl. Acad. Sci. USA 82 (1985) 2282-2286] as a probe, is reported. Sequence comparison of the clone EPZP6 with the human alpha 2M cDNA revealed the presence of five exons with the proper splice signals. Alignment of the corresponding amino acid (aa) sequence of these exons with the published partial pregnancy-zone protein (PZP) aa sequence (Sottrup-Jensen et al., Proc. Natl. Acad. Sci. USA 81 (1984) 7353-7357] showed a perfect match, thereby identifying EPZP6 as a PZP genomic clone. The clone MPAM16 showed a considerable degree of sequence conservation when compared to the human alpha 2M cDNA sequence, and several putative exons were identified. However, a frame-shift mutation leading to a premature stop codon was found in the coding sequence, classifying this gene as an alpha 2M pseudogene. Human alpha 2M, PZP and the related pseudogene were mapped to the human chromosome 12p12-13, with the help of gene-specific probes and in situ hybridization. This result was confirmed in Southern-blot experiments with DNA from a human-Ltk- mouse somatic-cell hybrid containing only a human isochromosome 12p in a mouse background.