Nondetectability of restriction fragments and independence of DNA fragment sizes within and between loci in RFLP typing of DNA

We provide experimental evidence showing that, during the restriction-enzyme digestion of DNA samples, some of the HaeIII-digested DNA fragments are small enough to prevent their reliable sizing on a Southern gel. As a result of such nondetectability of DNA fragments, individuals who show a single-band DNA profile at a VNTR locus may not necessarily be true homozygotes. In a population database, when the presence of such nondetectable alleles is ignored, we show that a pseudodependence of alleles within as well as across loci may occur. Using a known statistical method, under the hypothesis of independence of alleles within loci, we derive an efficient estimate of null allele frequency, which may be subsequently used for testing allelic independence within and across loci. The estimates of null allele frequencies, thus derived, are shown to agree with direct experimental data on the frequencies of HaeIII-null alleles. Incorporation of null alleles into the analysis of the forensic VNTR database suggests that the assumptions of allelic independence within and between loci are appropriate. In contrast, a failure to incorporate the occurrence of null alleles would provide a wrong inference regarding the independence of alleles within and between loci.

Pituitary adenylate cyclase-activating polypeptide stimulates steroidogenesis and adenosine 3',5'-monophosphate accumulation in cultured rat granulosa cells

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a novel neuropeptide with considerable homology to vasoactive intestinal peptide (VIP) and GH-releasing hormone (GHRH). Because we have shown previously that VIP and GHRH stimulate steroidogenesis in cultured rat granulosa cells independently of FSH, the present studies evaluated whether PACAP also stimulates steroidogenesis and compared its effects to those of VIP and GHRH. Granulosa cells cultured for 2 days with PACAP-27, VIP, or GHRH (10(-9)-10(-6) M) showed dose-dependent increases in the accumulation of progesterone, 20 alpha-dihydroprogesterone, and estrogen. The rank order of potency for the three peptides was PACAP >> VIP > GHRH. PACAP also increased cAMP accumulation and was again more potent than VIP. In addition, all three peptides synergistically augmented FSH-stimulated progesterone and 20 alpha-dihydroprogesterone accumulation with the same rank order of potency as above; however, only the highest dose of each peptide augmented estrogen accumulation. Further studies examined the effects of various androgens on these responses. PACAP-stimulated progesterone accumulation was minimal in the absence of androstenedione, but increased up to 40-fold in its presence. Other synthetic and naturally occurring androgens produced similar increases with a rank order of potency of R1881 > testosterone = androstenedione > dihydrotestosterone. Analysis of cAMP levels indicated that by 1 h after treatment with PACAP, cAMP levels within the cells increased by 4-fold, and this response was unaltered in the presence of androstenedione; however, by 48 h, cAMP levels had markedly declined, and this response was attenuated by androstenedione. These results demonstrate that PACAP stimulates steroidogenesis and cAMP accumulation in cultured rat granulosa cells, and it is more potent than its two homologs, VIP and GHRH. Because PACAP has been shown to be present within the ovary, these data indicate that this peptide may play a role in modulating ovarian steroidogenic activity.

Evaluation of 13 short tandem repeat loci for use in personal identification applications

Personal identification by using DNA typing methodologies has been an issue in the popular and scientific press for several years. We present a PCR-based DNA-typing method using 13 unlinked short tandem repeat (STR) loci. Validation of the loci and methodology has been performed to meet standards set by the forensic community and the accrediting organization for parentage testing. Extensive statistical analysis has addressed the issues surrounding the presentation of "match" statistics. We have found STR loci to provide a rapid, sensitive, and reliable method of DNA typing for parentage testing, forensic identification, and medical diagnostics. Valid statistical analysis is generally simpler than similar analysis of RFLP-VNTR results and provides powerful statistical evidence of the low frequency of random multilocus genotype matching.

Linkage disequilibria among (CA)n polymorphisms in the human dystrophin gene and their implications in carrier detection and prenatal diagnosis in Duchenne and Becker muscular dystrophies

Four short tandem repeat loci, characterized by length polymorphisms of (CA)n repeats, have been detected within introns 44, 45, 49, and 50 of the human dystrophin gene. The predicted heterozygosities for these loci range from 72 to 93%, and observed allele numbers range from 6 to 19 in 57 normal chromosomes, revealing their high degree of polymorphism. Evidence for significant disequilibria between the loci within introns 49 and 50 is found. These data appear to be consistent with observations of recombination frequencies between these markers and the length of the intron 44 in relation to the entire region. In addition, these four loci are collectively found to be 100% informative in carrier detection/prenatal diagnosis of Becker and Duchenne muscular dystrophies (B/DMD), whereas scoring the (CA)n markers within introns 45 and 49 alone gives a 99.6% success rate.

[125I-alpha-sec-butyl-p-hydroxybenzyl alcohol receptor competitive binding assays in animal body]

Based on the receptor competitive binding assays in the mice and rat body, it has been proved that both diazepam and alpha-sec-butyl-p-hydroxybenzyl alcohol (G-018) can inhibit 125I-G-018 binding with brain benzodiazepine receptor. Inhibiting effects were obvious in the cortex, cerebellum, hippocampus and midbrain. But in the medullao blongata and hypothalamus no inhibiting effect was observed. Experimental results have demonstrated that the inhibiting effect is consistent with distribution of benzodiazepine receptor in the brain. Also, experimental results have shown no difference between in vitro and in vivo. The G-018 binding with benzodiazepine receptor has been clarified under physiologic conditions.

Paternity evaluation in cases lacking a mother and nondetectable alleles

In parentage testing the formulae for computing paternity index and exclusion probability generally ignores the presence of nondetectable alleles at the loci tested. In contrast, it is now known that even when paternity testing is done with hypervariable DNA markers, nondetectable alleles should not be ignored. This work presents simple formulae needed with this consideration, to analyze paternity evaluation from DNA markers in cases where the mother of the disputed child is unavailable for testing. It is shown that even a modest frequency of nondetectable alleles (e.g., 2-5% per locus) may have a substantial impact on the paternity index when the child and/or the alleged father exhibits a single-banded DNA profile at a locus. Use of such formulae can generate a high probability of exclusion and a high paternity index when multiple independently segregating hypervariable DNA markers are used.

Sequential decrease in tight junctions as revealed by 7H6 tight junction-associated protein during rat hepatocarcinogenesis

A sequential decrease in the number of hepatocyte tight junctions during the course of rat hepatocarcinogenesis was demonstrated by immunohistochemistry with a new 7H6 monoclonal antibody generated in our laboratory. Semiquantitative analysis by confocal laser scanning microscopy revealed that the expression of 7H6 antigen was reduced in hyperplastic foci, hyperplastic nodules and hepatocellular carcinomas (HCC) to 43%, 28% and 25%, respectively, compared to corresponding normal liver tissues. 7H6 antigen was scarce in HCC with a trabecular pattern, whereas it was expressed intensely at the apical and basolateral membrane of HCC with a glandular pattern. Immunoblot analysis of 7H6 expression in hepatocellular carcinomas showed a decrease roughly coincident with that shown by immunohistochemistry. These results indicated, for the first time, that tight junctions decrease progressively during carcinogenesis, leading to disruption of cellular polarity and cellular adhesiveness.

Vascular architecture of the human optic chiasma and bitemporal hemianopia

The blood supply system of the optic chiasma was studied in 85 fresh human specimens using various histological and anatomical methods. Computer image analysis and ultrastructural examinations of the microvessel in 58 fetal specimens were also conducted. The authors found that the medial portion of the chiasma is a weak point in the microcirculation network. This weak point is apt to be disturbed first and become ischemic, causing disorders of the crossing optic nerve fibers and resulting in characteristic bitemporal visual field defects. SEM studies showed no ultrastructural difference between the capillaries at the medial and lateral portions of the chiasma. It was concluded that: 1) No special artery supplies the median chiasma the weak point of microcirculation at the median chiasma is due to its relatively scanty capillary distribution; 2) "lateral chiasma arteries" could provide a better blood supply to the lateral fibers and thus the nasal quadrantic visual field could be preserved in many late stages of visual field defect in sellar region tumors; 3) cases with pituitary microadenoma which is not sufficiently large to press the chiasma but involves bitemporal visual field defect are due to the tumor receiving "shunt-flow" (stealing blood) from the chiasma through the peri-infundibulum plexus.

Temporal averaging for quantification of lumen dimensions in intravascular ultrasound images

Quantitative analysis of arterial dimensions from high frequency intravascular ultrasound images (30 MHz) may be hampered by strong blood scattering. Replacement of blood by saline is one method to provide a clear view of the arterial lumen; another method is that of temporal averaging of successive ultrasound images. The accuracy of this latter method was tested by comparing the lumen area measurements on the temporal-averaged image, with the data of the same cross-section obtained from the single-frame and saline-filled images. The mean lumen area measured on the temporal-averaged images was similar to that measured on the single-frame images (mean difference: -0.02 +2- 1.16 mm2; p = ns). The mean lumen area of the saline-filled images was 8% larger than the values obtained from the temporal-averaged and single-frame images (mean difference: -1.14 +/- 0.85 mm2, p < 0.05), probably due to the difference in sound velocity between saline and blood. Intraobserver variation in the averaging method were 2.4 times smaller than the measurements of the single-frame images and close to the data obtained by saline injection (variation coefficient: single-frame: 8.8%; temporal-averaged: 3.6%; saline-filled: 2.9%). It is concluded that analysis from temporal-averaged images is more efficient, enabling accurate and reproducible measurement of the luminal dimensions from images containing blood scattering echoes. This technique is suitable to replace the laborious saline injection method and facilitates off-line quantitative analysis.

Statistical power of an exact test of Hardy-Weinberg proportions of genotypic data at a multiallelic locus

A computer algorithm for numerical evaluation of the statistical power of an exact test of Hardy-Weinberg genotypic proportions (HWP), developed here, indicates that the power is dependent on the number of segregating alleles as well as allele frequencies. While low levels of departure from the null hypothesis are difficult to detect from single-locus data, should such deviation be due to population substructuring, multiple loci, at each of which the number of segregating alleles is large (as seen with hypervariable loci), may easily detect even low levels of departure from HWP. Undetected small levels of departure may still provide conservative estimates of genotype frequencies from allele frequency data, following the current practice in forensic genetics.

Modulation of different K+ currents in Drosophila: a hypothetical role for the Eag subunit in multimeric K+ channels

We examined the role of the ether a go-go (eag) gene in modulation of K+ currents and the possibility of its protein product Eag as a subunit in the heteromultimeric assembly of K+ channels by voltage-clamp analysis of larval muscle membrane currents. Previous DNA sequence studies indicate that the eag gene codes for a polypeptide homologous to, but distinct from, the Shaker (Sh) K+ channel subunits (Warmke et al., 1991), and electrophysiological recordings revealed allele-specific effects of eag on four identified K+ currents in Drosophila larval muscles (Zhong and Wu, 1991). Further studies of eag alleles indicated that none of the eag mutations, including alleles producing truncated mRNA messages, eliminate any of the four K+ currents, and that the mutational effects exhibit strong temperature dependence. We found that both W7, an antagonist of Ca2+/calmodulin, and cGMP analogs modulated K+ currents and that their actions were altered or even abolished by eag mutations. These results suggest a role of eag in modulation of K+ currents that may subserve integration of signals at a converging site of the two independent modulatory pathways. The Sh locus is known to encode certain subunits of the IA channel in larval muscle. The existence of multiple eag and Sh alleles enabled an independent test of the idea of Eag as a K+ channel subunit by studying IA in different double-mutant combinations. An array of allele-specific interaction between eag and Sh was observed, which reflects a close association between the Sh and eag subunits within the IA channel. Taken together, our data strengthen the possibility that the eag locus provides a subunit common to different K+ channels. The role of the eag subunit for modulating channels, as opposed to that of Sh subunits required for gating, selectivity, and conductance of the channel, suggest a combinatorial genetic framework for generating diversified K+ channels.

Differential modulation of potassium currents by cAMP and its long-term and short-term effects: dunce and rutabaga mutants of Drosophila

The cAMP concentration in Drosophila is increased by mutations of the dunce (dnc) gene and decreased by mutations of the rutabaga (rut) gene. Such mutants provide a unique means for exploring the role of cAMP in functional and developmental regulation of membrane currents. Four distinct K+ currents have been identified in Drosophila larval muscle fibers, i.e. the voltage-activated transient IA and delayed IK and the Ca(2+)-activated fast ICF and slow ICS. Results from our voltage-clamp studies indicated that both IA and IK were increased in dnc alleles. Normal muscle fibers treated with dibutyryl-cAMP showed a similar increase of IA, but no significant effect on IK. In contrast to the dnc alleles, the rut mutations appeared to enhance ICS greatly while leaving the amplitude of other currents largely unchanged. In addition, the dibutyryl-cAMP-induced increase in IA was not observed in rut fibers. Caffeine and W7, which are known to interfere with several second messenger pathways, also modulated K+ currents in larval muscle fibers. The currents in dnc and rut fibers showed strikingly altered responses to caffeine and W7. The results demonstrate that the various K+ currents in Drosophila muscles are affected by altered cAMP cascades in the mutants. The fact that not all dnc and rut mutant defects can be mimicked or reversed by acute application of cAMP suggests that long-term modulation of K+ currents by cAMP may involve mechanisms distinct from the short-term effect of cAMP.

On allele frequency computation from DNA typing data

Forensic applications of DNA typing data require the estimation of the frequencies of all observed alleles, which is currently done by a fixed set of groupings (binning) of alleles in a database. Recently it's validity has been questioned on the ground that when a DNA fragment size is close to a bin boundary, the frequencies of all adjacent bins should be added. On the contrary, the current forensic database indicates that when the match window of a DNA fragment overlaps 2 bins, it is enough to consider the bin with the larger frequency, and this never underestimates the frequency within the match interval with the current choice of fixed-bin widths. On average, the current fixed-bin procedure yields an allele frequency at least 2-fold higher than that of a floating-bin.

Monoclonal antibody 7H6 reacts with a novel tight junction-associated protein distinct from ZO-1, cingulin and ZO-2

The tight junction is an essential element of the intercellular junctional complex; yet its protein composition is not fully understood. At present, only three proteins, ZO-1 (Stevenson, B. R., J. D. Siliciano, M. S. Mooseker, and D. A. Goodenough. 1986. J. Cell Biol. 103:755-766), cingulin (Citi, S., H. Sabanay, R. Jakes, B. Geiger, and J. Kendrick-Jones. 1988. Nature (Lond.). 333:272-275) and ZO-2 (Gumbiner, B., T. Lowenkopf, and D. Apatira. 1991. Proc. Natl. Acad. Sci. USA. 88:3460-3464) are known to be associated with the tight junction. We have generated a monoclonal antibody (7H6) against a bile canaliculus-rich membrane fraction prepared from rat liver. This 7H6 antigen was preferentially localized by immunofluorescence at the junctional complex regions of hepatocytes and other epithelia, and 7H6-affiliated gold particles were shown electron microscopically to localize at the periphery of tight junctions. Immunoblot analysis of a bile canaliculus-rich fraction of rat liver using 7H6, anti-ZO-1 antibody (R26.4C), and anti-cingulin antibody revealed that 7H6 reacted selectively with a 155-kD protein, whereas R26.4C reacted only with a 225-kD protein. Anti-cingulin antibody reacted solely with 140 and 108-kD proteins, indicating that the protein recognized by 7H6 is immunologically different from ZO-1 and cingulin. Immunoprecipitation of detergent extracts obtained from metabolically labeled MDCK cells with R26.4C coprecipitated a 160-kD protein, which corresponds to ZO-2, with ZO-1. However, 7H6 did not react with the 160-kD protein. These results strongly suggest that the 7H6 antibody recognizes a novel tight junction-associated protein different from ZO-1, cingulin and ZO-2.

Effect of balloon angioplasty on femoral artery evaluated with intravascular ultrasound imaging

BACKGROUND

Intravascular ultrasound was used to assess the immediate effect of balloon angioplasty on the superficial femoral artery.

METHODS AND RESULTS

In 16 consecutive patients, corresponding ultrasonic cross sections (n = 72) before and after balloon angioplasty were qualitatively and quantitatively analyzed. The qualitative data were compared with angiographic findings. Before intervention, the angiographically demonstrated obstructive lesions were confirmed by intravascular ultrasound. Ultrasound enabled discrimination between soft (n = 43) and hard (n = 29) lesions, as well as between eccentric (n = 57) and concentric (n = 15) lesions. After balloon angioplasty, the presence of a dissection assessed angiographically in 14 patients was confirmed by intravascular ultrasound. Additional morphological information provided by ultrasound included plaque rupture in 14 patients and internal lamina rupture in six patients. Quantitative ultrasound data revealed an increase in free lumen area from 9.7 +/- 4.7 to 18.3 +/- 7.0 mm2 (p less than or equal to 0.01), an increase in minimal lumen diameter from 2.8 +/- 0.7 to 3.6 +/- 1.2 mm (p less than or equal to 0.01), and an increase in media-bounded area from 21.7 +/- 5.4 to 28.3 +/- 5.8 mm2 (p less than or equal to 0.01). The lesion area for the majority of cases (n = 32) remained unchanged (13.0 +/- 4.9 mm2 versus 12.9 +/- 4.6 mm2), or the lesion disappeared partially (from 9.1 +/- 0.9 to 4.3 +/- 1.4 mm2, n = 4, p less than or equal to 0.01) or totally (from 10.1 +/- 4.2 to 0 mm2, n = 6). Stretching of the arterial wall was further evidenced by medial thinning from 0.55 +/- 0.19 to 0.34 +/- 0.11 mm (p less than or equal to 0.01).

CONCLUSIONS

Luminal enlargement by balloon dilatation is achieved primarily by overstretching the arterial wall, with the lesion volume remaining practically unchanged. Overstretching is accompanied almost always by dissection and plaque rupture and occasionally by an internal lamina rupture.

[Quantitative anatomical study of the fetal optic chiasmal capillaries]

The spatial distribution of capillaries in the optic chiasma was studied quantitatively in 51 fetuses, 8 newborns and 4 babies to reveal that the capillary density was lower in the chiasmal median portion, which was therefore a weak point of blood supply. This finding may be a contributing factor for bitemporal hemianopsia due to neoplasms from the sella turcica.

[Effective chemical constituents of Artemisia argyi Levl. et Vant for inhibition of platelet aggregation]

beta-Sitosterol and eupatilin were isolated and identified from Artemisia argyi. Both of them showed marked inhibition of platelet aggregation.

Synaptic plasticity in Drosophila memory and hyperexcitable mutants: role of cAMP cascade

Activity-dependent synaptic plasticity has been implicated in the refinement and modification of neural circuits during development and learning. Previous studies show that activity-induced facilitation and potentiation are disrupted at larval neuromuscular junctions in the memory mutants dunce (dnc) and rutabaga (rut) of Drosophila. The diminished learning-memory capacity and synaptic transmission plasticity have been associated with altered cAMP levels since dnc affects the cAMP-specific phosphodiesterase and rut affects adenylate cyclase. In this study, the morphology of larval motor axon terminals was examined by anti-HRP immunohistochemistry. It was found that the numbers of terminal varicosities and branches were increased in dnc mutants, which have elevated cAMP concentrations. Such increase was suppressed in dnc rut double mutants by rut mutations, which reduce cAMP synthesis. More profuse projections of larval motor axons have also been reported in double-mutant combinations of ether à go-go (eag) and Shaker (Sh) alleles, which display greatly enhanced nerve activity as a result of reduction in different K+ currents. Therefore, we examined combinations of dnc and rut with eag and Sh mutations to explore the possible relation between activity- and cAMP-induced morphological changes. We found that the expanded projections in dnc were further enhanced in double mutants of dnc with either eag or Sh, an effect that could again be suppressed by rut. The results provide evidence for altered plasticity of synaptic morphology in memory mutants dnc and rut and suggest a role of cAMP cascade in mediating activity-dependent synaptic plasticity.

Validation of quantitative analysis of intravascular ultrasound images

This study investigated the accuracy and reproducibility of a computer-aided method for quantification of intravascular ultrasound. The computer analysis system was developed on an IBM compatible PC/AT equipped with a framegrabber. The quantitative assessment of lumen area, lesion area and percent area obstruction was performed by tracing the boundaries of the free lumen and original lumen. Accuracy of the analysis system was tested in a phantom study. Echographic measurements of lumen and lesion area derived from 16 arterial specimens were compared with data obtained by histology. The differences in lesion area measurements between histology and ultrasound were minimal (mean +/- SD: -0.27 +/- 1.79 mm2, p greater than 0.05). Lumen area measurements from histology were significantly smaller than those with ultrasound due to mechanical deformation of histologic specimens (-5.38 +/- 5.09 mm2, p less than 0.05). For comparison with angiography, 18 ultrasound cross-sections were obtained in vivo from 8 healthy peripheral arteries. Luminal areas obtained by angiography were similar to those by ultrasound (-0.52 +/- 5.15 mm2, p greater than 0.05). Finally, intra- and interobserver variability of our quantitative method was evaluated in measurements of 100 in vivo ultrasound images. The results showed that variations in lumen area measurements were low (5%) whereas variations in lesion area and percent area obstruction were relatively high (13%, 10%, respectively). Results of this study indicate that our quantitative method provides accurate and reproducible measurements of lumen and lesion area. Thus, intravascular ultrasound can be used for clinical investigation, including assessment of vascular stenosis and evaluation of therapeutic intervention.

Alteration of four identified K+ currents in Drosophila muscle by mutations in eag

Voltage-clamp analysis of Drosophila larval muscle revealed that ether à go-go (eag) mutations affected all identified potassium currents, including those specifically eliminated by mutations in the Shaker or slowpoke gene. Together with DNA sequence analysis, the results suggest that the eag locus encodes a subunit common to different potassium channels. Thus, combinatorial assembly of polypeptides from different genes may contribute to potassium channel diversity.

[Study of the mechanism of gastrodin and derivatives of gastrodigenin]

The tritiated alpha-isobutylhydroxybenzyl alcohol (3H-G018) was found to be able to bind benzodiazepine (BZ) receptor on the rat brain membrane. The 125I labeled G-018 also had the similar binding activity with this receptor. In the present investigation, we observed that gastrodigenin and its derivatives inhibited the 125I-G018 binding of BZ receptor competitively, but no inhibition was observed with gastrodin. The results suggested that Gastrodigenin was bound to BZ receptor, and otherwise, gastrodin would have no direct interaction with BZ receptor. Probably, it might metabolize into gastrodigenin in vivo, and then got through the blood brain barrier and bound to BZ receptor, which mediated its pharmacological effects on the central nervous system.

Altered synaptic plasticity in Drosophila memory mutants with a defective cyclic AMP cascade

Synaptic transmission was examined in Drosophila mutants deficient in memory function. These mutants, dunce and rutabaga, are defective in different steps of the cyclic adenosine 3',5'-monophosphate (cAMP) cascade. In both dunce and rutabaga larvae, voltage-clamp analysis of neuromuscular transmission revealed impaired synaptic facilitation and post-tetanic potentiation as well as abnormal responses to direct application of dibutyryl cAMP. In addition, the calcium dependence of transmitter release was shifted in dunce. The results suggest that the cAMP cascade plays a role in synaptic facilitation and potentiation and indicate that synaptic plasticity is altered in Drosophila memory mutants.

Studies on bioactive components from Chinese medicinal plants

Several novel bioactive components isolated from Chinese medicinal plants will be presented. These include novel maytansinoid tumor inhibitors, some new ent-kaurane and rosane diterpenoids from Mallotus anomalus Meer et Chun (Euphorbiaceae), as well as novel insecticide, stemona alkaloids from Stemona parviflora C. H. Wright (Stemonaceae). Both are native plants of Hainan island, China. 2D NMR techniques such as mono and hetero-COSY, NOESY, COLOC as well as 1H-NMR line broadening effect were utilized for structure elucidation. The separation techniques, structure elucidations and bioassay results will be reported.

Intravascular ultrasound and vascular intervention

An intravascular ultrasonic imaging device (40 MHz) was used to obtain in vitro ultrasonic images and matching histologic cross-sections, derived from human vascular specimens. The feasibility of assessing vessel wall morphology as well as the ability to accurately document plaque thickness was determined. Based on the echogenicity of the arterial media, intravascular ultrasound could distinguish muscular arteries from elastic arteries, veins, and bypass grafts. The hypoechoic media only present in the muscular type of artery proved to be an essential landmark to document superimposed atherosclerosis. Plaque thickness calculated in these arteries showed close relationship with the corresponding histologic cross-section. Using real-time in vivo intravascular imaging (30 MHz), the morphology of the vessels interrogated was studied. The dynamic change of the arterial wall, as well as the outcome after intervention, is discussed.

Morphological plasticity of motor axons in Drosophila mutants with altered excitability

An anatomical and electrophysiological study of Drosophila mutants has been made to determine the effect of altered electrical activity on the development and maintenance of larval neuromuscular junctions. We examined motor axon terminals of (1) hyperexcitable mutants Shaker (Sh), ether a go-go (eag), Hyperkinetic (Hk), and Duplication of para+ (Dp para+); and (2) mutants with reduced excitability, no action potential (napts) and paralytic (parats 1). Nerve terminals innervating larval body-wall muscles were visualized by using anti-HRP immunocytochemistry, which specifically stains neurons in insect species. In wild-type larvae, motor axon terminals were distributed in a stereotypic fashion. However, in combinations of eag and Sh alleles, the basic pattern of innervation was altered. There was an increase in both the number of higher-order axonal branches over the muscles and the number of varicosities on the neurites. A similar phenomenon was found in the double mutant Hk eag and, to a lesser extent, in Dp para+ and Dp para+ Sh mutants. It is known that at permissive temperature the napts, but not parats 1, mutation decreases excitability of larval motor axons and suppresses the behavioral phenotypes of Sh, eag, and Hk. In the mutant napts (reared at permissive temperature), a slight decrease in the extent of branching was observed. Yet, when combined with eag Sh, napts completely reversed the morphological abnormality in eag Sh mutants. No such reversion was observed in parats 1 eag Sh mutants. The endogenous patterns of electrical activity at the neuromuscular junction were analyzed by extracellular recordings in a semi-intact larval preparation. Recordings from wild-type body-wall muscles revealed rhythmic bursts of spikes. In eag Sh mutants, this rhythmic activity was accompanied by or superimposed on periods of strong tonic activity. This abnormal pattern of activity could be partially suppressed by napts in combination with eag Sh.

[Synthesis of 4-[(4-chlorophenyl) (5-fluoro-2-hydroxyphenyl) methylene amino]butyrates and its anticonvulsant activity]

It is known that gamma-aminobutyric acid (GABA) plays an important role in the pathophysiology of epilepsy. Under physiological conditions it is very difficult for GABA to cross the blood-brain barrier. It is likely that the esters of GABA, Which easily enter the brain, will have useful therapeutic properties. With this in mind, we have designed and synthesized 8 derivatives (IVa to IVh) of gamma-aminobutyric acid with an imine to link a lipophilic carrier in order to facilitate the passage of gamma-aminobutyric acid to cross the blood-brain barrier. All the eight synthesized title compounds were evaluated as anticonvulsants in mice via the Antiepileptic Drug Development Program of NIH. The compounds IVb and IVf showed anticonvulsant activity.

[Clinical therapeutic effect of xifukang in 53 patients with silicosis]

Xifukang is a compound preparation of Chinese herbs consisting of Hanbane grugs mainly. Since 1987, the significant efficiency have been obtained in treatment of 53 patients suffering from silicosis by self-control study. The results indicated that the clinical manifestations including dyspnea, cough, sputum production, chest pain, weakness, etc. were markedly improved (P less than 0.01) and measurements of pulmonary function (FVC, FEV and MVV) significant enhanced (P less than 0.01). After treatment 20 cases roentgenogram exam showed that the lung's clarity and the limited emphysema were improved, the silicolic nodule and mass-mergence opacity of 3 cases lessened in some degree. By discussing the effect of Xifukang which might lower the collagen protein content of experimental silicosis of Wistar rats and improve pathomorphous. The authors concluded that the therapeutic mechanism of Xifukang could be the actions of this remedy on promoting blood circulation to eliminate blood stasis dredging microcirculation, increasing ventilation/perfusion (VA/Q), protecting dust-cells, resisting fibrosis, regulating immune function, enhancing lung clearance, postponing and preventing development of silicosis.

[Chemical constituents of the leaves of Crataegus pinnatifida Bge. var. major N. E. Br]

Compounds were isolated from the aqueous extract of the leaves of Crataegus pinnatifida var. major and seven of them were identified as 2-(4-hydroxybenzyl)malic acid, quercetin, hyperin, vitexin, rhamnosylvitexin, diethylamine hydrochloride and sorbitol respectively by UV, IR, NMR, MS, some chemical techniques by comparison with the standard spectra of known compounds.

[Establishment of a malignant astrocytoma cell line TJ-8510 and its characterization]

A malignant astrocytoma cell line TJ-8510 derived from temporoparietal astrocytoma Grade III was established. At present, it has survived for more than 34 months passaging through 220 generations. According to its features in cell kinetics, cytogenetics, morphology, biochemistry and heterotransplantation, it was still identified as malignant astrocytoma. This cell line may be useful in further research on glioma.

Actions of dendrotoxin on K+ channels and neuromuscular transmission in Drosophila melanogaster, and its effects in synergy with K+ channel-specific drugs and mutations

The blockade of K+ channels and enhancement of neuromuscular transmission by dendrotoxin (DTX), a convulsant peptide from mamba snake venom, were examined in normal and mutant larval preparations of Drosophila. Two-microelectrode voltage-clamp experiments showed that DTX reduced the transient K+ current, IA, in muscle membrane. This effect was suppressed by raising the Mg2+ concentration or by lowering the temperature. The interaction of DTX with Mg2+ was further analyzed at a low cation concentration, at which DTX reduced both IA and the delayed rectifier IK. These results were correlated with the action of DTX on the neuromuscular junction. Its facilitatory effect on excitatory junctional potentials (EJPs) was relatively mild but the effect was drastically enhanced when combined with certain mutations and K+ channel blocking drugs, leading to repetitive or prolonged giant EJPs. Only the mutations or drugs that reduced IK or the Ca2(+)-dependent K+ current, ICF, could yield these synergistic effects with DTX. In contrast, the abnormal EJPs caused by the mutation or drug that blocked IA were not further enhanced by DTX, indicating that DTX also affects IA at the neuromuscular junction. Thus, the A-type K+ channels in muscle and nerve terminals appeared very similar in their sensitivity to the specific toxin, drugs and mutations examined here.

[Evaluation of coronary artery fistula using a color Doppler flow imaging technique]

Two unusual cases with coronary artery fistula were reported. The diagnoses were first made by color Doppler flow imaging and confirmed by selective coronary angiography and operation. In the first case, color Doppler revealed a continuous flow signal within the dilated left coronary artery and a turbulent jet within the right atrium. In the second case, color Doppler showed turbulent flow signals which could be traced from the proximal left coronary artery, along the left ventricular posterior wall and into the left ventricle. The high velocities at the site of drainage of fistula were recorded by the continuous-wave Doppler and the calculated pressure gradient confirmed that the abnormal flow was from the systemic circulation. We are of the opinion that color Doppler flow imaging is a reliable technique for detecting coronary artery fistula and the combination of color Doppler with continuous-wave Doppler is essential for evaluating the hemodynamics of the shunt flow.