Differential regulation of cellular activities by GTPase-activating protein and NF1

The regulation of the GTPase activity of the Ras proteins is thought to be a key element of signal transduction. Ras proteins have intrinsic GTPase activity and are active in signal transduction when bound to GTP but not following hydrolysis of GTP to GDP. Three cellular Ras GTPase-activating proteins (Ras-gaps) which increase the GTPase activity of wild-type (wt) Ras but not activated Ras in vitro have been identified: type I and type II GAP and type I NF1. Mutations of wt Ras resulting in lowered intrinsic GTPase activity or loss of response to cellular Ras-gap proteins are thought to be the primary reason for the transforming properties of the Ras proteins. In vitro assays show type I and type II GAP and the GAP-related domain of type I NF1 to have similar biochemical properties with respect to activation of the wt Ras GTPase, and it appears as though both type I GAP and NF1 can modulate the GTPase function of Ras in cells. Here we report the assembling of a full-length coding clone for type I NF1 and the biological effects of microinjection of Ras and Ras-gap proteins into fibroblasts. We have found that type I GAP, type II GAP, and type I NF1 show markedly different biological activities in vivo. Coinjection of type I GAP or type I NF1, but not type II GAP, with wt Ras abolished the ability of wt Ras to induce expression from an AP-1-controlled reporter gene. We also found that serum-stimulated DNA synthesis was reduced by prior injection of cells with type I GAP but not type II GAP or type I NF1. These results suggest that type I GAP, type II GAP, and type I NF1 may have different activities in vivo and support the hypothesis that while type I forms of GAP and NF1 may act as negative regulators of wt Ras, they may do so with differential efficiencies.

Perceptions of practice problems encountered by family physicians, pediatricians, and orthopedic surgeons

Information about physicians' practice problems was solicited through a structured questionnaire mailed to a group of family physicians, pediatricians, and orthopedic surgeons. Overall, a lack of personal time was the major concern across the three groups of physicians. Comparisons among the three types of physicians revealed two patterns: Family physicians reported more concerns in the "interpersonal" dimension, whereas orthopedic surgeons had more concerns in the "legal-economic" dimension. These patterns of differences persisted with two variables controlled: gender and time period in which they completed their residency program. These findings indicate that physicians' concerns in their practice vary among the specialties, and they imply that the changed economy and reimbursement system might have more impact on one than the other. Thus the effectiveness of residency training and continuing education might be improved by emphasizing the specialty-related problems in practice.

Drift of the sialyl-linkage specific recognition of the sialidase of influenza B virus isolates

Sialyl-linkage specificity of the sialidase of influenza B viruses isolated in different years from 1940 through 1990 (B/Lee/40,B/Setagaya/3/56,B/Tokyo/7/66,B/Kagoshima/1/68, B/Gifu/2/73, B/Kanagawa/3/76, B/Ibaraki/2/85, B/Yamagata/16/88, and B/Bangkok/163/90) was studied with N-acetylneuraminyl (alpha 2-3)- and (alpha 2-6)-lactoses, GM3 gangliosides containing the same sialyl-oligosaccharide sequences as sialyllactose, and also with type I and type II lacto-series gangliosides carrying Neu5Ac alpha 2-3Gal and NeuAc alpha 2-6Gal linkages as substrates. From an examination of up to nine strains, the sialidases of all viruses preferentially hydrolyze substrates with Neu5Ac alpha 2-3Gal linkage rather than the Neu5Ac alpha 2-6Gal linkage. It was found that the sialidase activity toward Neu5Ac alpha 2-6Gal linkage relative to Neu5Ac alpha 2-3Gal linkage is increased in later strains, whether sialyllactose or ganglioside is used as the substrate. These results suggested that the sialidase of influenza B virus isolates has shown a drift in linkage specificity which correlates with the year of isolation.

Evaluation of brain function in acute carbon monoxide poisoning with multimodality evoked potentials

The median nerve somatosensory evoked potentials (SEP), pattern reversal visual evoked potentials (VEP), and brain stem auditory evoked potentials (BAEP) were studied in 109 healthy adults and in 88 patients with acute carbon monoxide (CO) poisoning. The upper limits for normal values of peak and interpeak latencies of multimodalities of evoked potentials in the reference group were established by a stepwise multiple regression analysis. SEP changes selectively affecting N32 and N60 were found in 78.8% of patients. There was prolonged P100 latency of VEP in 58.2% of the cases examined. The prevalence of BAEP abnormalities in comatose patients (36%) was significantly higher than that (8.6%) in conscious patients. BAEP abnormalities were most frequently seen in comatose patients who had diminished brain stem reflexes (77.8%). It has been found that a consistent abnormality involving N20 and subsequent peaks in SEP, a remarkable prolongation of P100 latency in VEP, or a prolongation of III-V interpeak latency in BAEP as well as the reoccurrence of evoked potential abnormalities after initial recovery all indicate unfavorable outcomes in patients with acute CO poisoning. The multimodality evoked potentials have proved to be sensitive indicators in the evaluation of brain dysfunction and in the prediction of prognosis of acute CO poisoning and the development of delayed encephalopathy.

Plasma ascorbic acid concentrations relate inversely to blood pressure in human subjects

This study relates antioxidant status and blood pressure (BP) in 168 healthy residents of Augusta, GA, following usual diets. BP ranges were systolic (S) 84-152, mean 112 +/- 1 mm Hg, and diastolic (D) 52-96, mean 72 +/- 1 mm Hg. Plasma concentrations of ascorbic acid (AA) were significantly inversely related to SBP (r = -0.18, P < 0.05) and DBP (r = -0.20, P < 0.01); with regression equations SBP vs AA = -0.083C + 116 and DBP = -0.077C + 76. Highest and lowest quintiles of AA differed significantly in mean SBP (108 +/- 2, 113 +/- 2 mm Hg) and DBP (69 +/- 1, 74 +/- 2), P < 0.05. Plasma AA concentrations were significantly lower in the smokers. By deleting smokers, the inverse relations of SBP and DBP with plasma AA and the slopes of the equation were enhanced. Plasma selenium, alpha-tocopherol, alpha-tocopherol:cholesterol ratio, retinol and taurine were not related to BP; whereas male gender, body mass index, body fat distribution, plasma cholesterol, low density lipoprotein cholesterol, and triglycerides correlated.

Longitudinal comparison of the academic performances of Asian-American and white medical students

PURPOSE

To compare the academic performances of Asian-American medical students--before, during, and after medical school--with those of white students.

METHOD

The 140 Asian-American graduates and 2,269 white graduates from the classes of 1981-1992 at Jefferson Medical College were studied prospectively: data on academic performance, indebtedness, and delayed graduation were analyzed and compared for all the graduates. F-tests, chi-square tests, and regression models were used.

RESULTS

The Asian-Americans had statistically significantly higher scores on the SAT (Scholastic Aptitude Test) quantitative subtest and on the MCAT (Medical College Admission Test) chemistry, physics, and science problems subtests; the whites had significantly higher scores on the MCAT reading subtest; third-year grade-point averages for required clerkships; and scores on National Board of Medical Examiners Part I, II, and III examinations (NBME I, II, and III). No significant difference was found in the other performance measures, including ratings in the first year of residency. Regression analysis showed that the MCAT reading score was the major predictor of Asian-Americans' performances on the NBME I and II.

CONCLUSION

Because the MCAT reading score is the major predictor of later performance for Asian-American students, schools should consider employing different criteria in predicting and monitoring these students' performances.

Attendings' and residents' teaching role and students' overall rating of clinical clerkships

The study was conducted with a sample of third-year students (n = 584) at Jefferson Medical College to explore students' perception of patterns of differences between attending physicians and residents in their teaching behaviors during clinical clerkships. Attending physicians' teaching behaviors were perceived more in a mentorship mode whereas residents' teaching behaviors were equally divided between mentorship and preceptorship modes. Attending physicians and residents' teaching behaviors varied among clerkships. Results were discussed in terms of difference of teaching roles played by attending physicians and residents and relationship of the teaching behaviors to students' overall rating of clerkship.

Genotypic and antigenic identification of two new strains of spotted fever group rickettsiae isolated from China

Four isolates of spotted fever group rickettsiae isolated from ticks in China were compared with all known species and strains of spotted fever group rickettsiae by immunofluorescence assay, DNA polymerase chain reaction followed by restriction endonuclease fragment length polymorphism analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western immunoblot. The Chinese isolates belonged to three types, including a novel serotype which has not been described before. One isolate obtained from tick ova of Dermacentor nuttallii in Inner Mongolia was antigenically and genotypically identical to Rickettsia sibirica. Two isolates obtained from Dermacentor sinicus collected from Beijing were identical, different from other members of spotted fever group rickettsiae but apparently closely related to R. sibirica. HA-91, a strain isolated from Hyalomma asiaticum bv. kozlovi olenew, was antigenically and genotypically unique among spotted fever group rickettsiae, and we feel that data presented here should prompt consideration of it as a new species on the basis of current rickettsial taxonomy.

STE50, a novel gene required for activation of conjugation at an early step in mating in Saccharomyces cerevisiae

A new gene, STE50, which plays an essential role in cell differentiation in Saccharomyces cerevisiae was detected and analysed. STE50 expression is not cell type-specific and its expression in MATa and MAT alpha cells is unaffected by pheromones. When present on a high copy number plasmid, STE50 causes supersensitivity to alpha-pheromone, and increases the level of alpha-pheromone-induced transcription of FUS1 in haploid a cells. Mutants bearing either of the two gene disruptions, ste50-1 or ste50-2, are sterile and have a modulated sensitivity to alpha-pheromone. The overexpression of STE4 (G beta) in wild-type cells elicits a constitutive growth arrest signal, however this phenotype is suppressed by a C-terminal truncation mutation in STE50 (ste50-2). In contrast, the constitutive activation of the pheromone response pathway caused by disruption of GPA1 (G alpha) is not suppressed in ste50-2 mutants. The ste50-2 mutation partially suppresses the desensitisation defect of the sst2-1 mutation, and the resulting ste50-2 sst2-1 mutants restore fertility. Our results indicate that the ste50-2 mutant may have a defect in adaptation (hyperadaptation), and suggest a possible interaction of STE50-2 with the G alpha subunit of the G protein.

Hypoxia-mediated impaired differentiation by LLC-PK1 cells: evidence based on the protein kinase C profile

We recently reported that mild hypoxia in LLC-PK1 cells, grown in standard fashion under a still layer of overlying medium at 5% CO2/18% O2 environment, result in decreased oxidative metabolism and impaired differentiated functions in comparison to adequately oxygenated cultures maintained either under a higher oxygen (36% O2) environment or conditions of continuous rocking of the media fluid. In the present study, subcellular distribution of a regulatory enzyme protein kinase C (PKC) was examined between hypoxic still and normoxic rocked LLC-PK1 cells. Subconfluent cultures of hypoxic LLC-PK1 cells exhibited significantly lower and predominantly membrane-bound PKC activity in comparison to mostly cytosolic localization of this enzyme in normoxic rocked cells. One hour of exposure of adequately oxygenated-rocked LLC-PK1 cells with the phorbol ester TPA, a dedifferentiating agent that did not effect the cell ATP content, resulted in significant inhibition of dome formation and sodium-dependent glucose transport activity, a partial loss of pH-responsive ammoniagenesis, and almost complete translocation of protein kinase C activity from cytosol to the membrane pool; all of which resembles the behavior of hypoxic still cultured cells. In addition, acute re-oxygenation of hypoxic still cultures by rocking the media fluid for one hour resulted in an increase in cell ATP content to the cellular levels of ATP observed in normoxic rocked cells. However, all the parameters of differentiation were unaffected by re-oxygenation. These studies support the notion that hypoxia can act in some primary fashion, independent of its effects on energy metabolism, to impair cellular differentiation in LLC-PK1 cells. They also raise the possibility that activation of protein kinase C may act as an important mediator in this process.

The relationship between gastric mucosal changes and nitrate intake via drinking water in a high-risk population for gastric cancer in Moping county, China

There are conflicting reports on whether nitrate intake is related to gastric carcinogenesis. In this laboratory/field study from a high-risk area for gastric cancer, we analysed 178 samples of drinking water for nitrate and nitrite, and examined the relationship between gastric mucosal lesions (including gastric cancer) and quality of different types of drinking water and nitrate intake via water. The results showed that the nitrate content in the local drinking water was generally very high, with a mean of 109.6 mg/l (range 4.4-497.2 mg/l). There were significant differences in the nitrate content in drinking water from different wells in qualitatively different types of water. The histological changes were closely related to the quality of drinking water and its nitrate content. The results suggest that nitrate in drinking water probably plays an important role in gastric carcinogenesis and that in future aetiological studies of gastric cancer should include more information on well depth, the presence of public or private wells and nitrate content of water.

Tissue-specific expression of a rat intestinal mucin-like peptide

Expression of the gene for a rat intestinal mucin-like peptide (MLP) was studied by Northern-blot analyses of RNA prepared from a panel of rat tissues. Four probes (A-D) were constructed so as to span a 3.5 kb-long cDNA for rat MLP, and used for hybridization. Positive signals were obtained in intestine and colon, whereas lung, liver, stomach, submandibular gland and spleen were negative. The only transcript detected was approx. 9.5 kb in size. No mRNA splice variants were found. Hybridization in situ using probe B1, which corresponds to a cysteine-rich region near the C-terminus of MLP, confirmed that the gene for MLP is expressed by goblet cells of rat intestine and colon.

A serine, threonine and proline-rich region near the carboxyl-terminus of a rat intestinal mucin peptide

Further sequencing of a cDNA encoding the C-terminal region of a rat intestinal mucin peptide reveals a region corresponding to 258 amino acids enriched in serine, threonine and proline, but no typical mucin-like tandem repeat structures. Between this region and a previously described stretch of 4.5 degenerate S,T,P-rich tandem repeats, there is a 42 amino acid cysteine-rich segment. The discontinuity of cysteine-rich and S,T,P-rich areas near the C-terminus has not been observed in other mammalian mucin structures reported to date.

Protein synthesis during germination of heterothallic yeast ascospores

Protein synthesis during ascospore germination of the heterothallic Saccharomyces cerevisiae strain AP-3 was investigated. Protein synthesis in the germinating ascospores appeared to begin approximately 20 min following glucose initiation. Since RNA synthesis did not start until approximately 70 min after the onset of germination, strain AP-3 ascospores must contain RNA which is ready for immediate translation. Both trehalase and glyceraldehyde-3-phosphate dehydrogenase activities were found to be affected by the onset of germination. Trehalase activity was found to increase severalfold following 60 min of spore germination but remained relatively constant over the subsequent 120 min examined. Dehydrogenase activity was not detectable in AP-3 ascospores but was measurable in germinating ascospores.

[Textual study on traditional Chinese drugs caodoukou and baidoukou]

Through a critical study of herbalogy, it is concluded that the mature seeds of Alpinia zermubet were used as caodoukou in ancient times. The original plant of Yutao recorded in Zhiwu Mingshi Tukao may be the species of Alpinia katsumadai. Baidukou used in ancient times may be the seeds of Alpinia katsumadai found in the south of China, or Amomum compactum and Am. kravanh imported from foreign countries.

Characterization of human adenylate kinase 3 (AK3) cDNA and mapping of the AK3 pseudogene to an intron of the NF1 gene

We have isolated cDNA clones for human adenylate kinase isozyme 3 (AK3) with a genomic probe from the neurofibromatosis type 1 (NF1) region. Three overlapping clones isolated from a human frontal-cortex cDNA library gave rise to a consensus sequence of 1.7 kb. The open reading frame identified in this sequence predicted a peptide of 223 residues. A database search revealed striking homology, about 58% amino acid sequence identity, between this predicted protein and bovine AK3. Human AK3 protein also showed significant homology to other members of the adenylate kinase family isolated from various species. Genomic Southern analysis suggested that multiple AK3 loci exist in the human genome, including one located in an intron of NF1 on chromosome 17. The chromosome-17 locus appears to be a processed pseudogene, since it is intronless and contains a polyadenylate tract; it nevertheless retains coding potential because the open reading frame is not impaired by any observed base substitutions.

[Macrological identification of Chinese drug dangshen (radix Codonopsis)]

Macrological characters of 17 reference crude drugs from Codonopsis and Campanumoea were observed. Identification of 110 samples collected from 18 provinces of China indicated that more than 70 percent of the commercial Dangshen is derived from Codonopsis pilosula.

Structural determination of gangliosides that bind to influenza A, B, and C viruses by an improved binding assay: strain-specific receptor epitopes in sialo-sugar chains

An improved binding assay for detection of ganglioside receptors for influenza A, B, and C viruses was developed. In this system, the virions bound to gangliosides that were developed on a silica gel thin-layer plate were detected by mouse monoclonal antibody against viral hemagglutinin and peroxidase-conjugated anti-mouse immunoglobin. No hydrolysis of the gangliosides by viral receptor-destroying enzyme was detected in the present condition. The reactivity of the viruses to gangliosides depended on the amount of developed gangliosides (10 pmols-10 nmols), the molecular species of sialic acid, and their sugar sequences. Human influenza A (PR/8/34), B (Lee/40), and C (Ann Arbor/1/50) viruses bound different receptor epitopes of sialo-sugar chains of gangliosides. The A/PR/8 virus bound most effectively to Neu5Ac-containing lacto-series gangliosides carrying type I and type II sugar chains, followed by ganglio-series and hematoside-series gangliosides. The A/PR/8 virus weakly bound to Neu5Ac alpha 2,6lactotetraosylceramide [IV6(Neu5Ac)Lc4Cer] and Neu5Ac alpha 2,6paragloboside [IV6(Neu5Ac)nLc4Cer] carrying Neu5Ac alpha 2,6Gal sequence, although their Neu5Ac alpha 2,3Gal derivatives were the most potent gangliosides tested. B/Lee/40 bound restrictively to IV6(Neu5Ac)Lc4Cer and IV6(Neu5Ac)nLc4Cer, which carry Neu5Ac alpha 2,6Gal sequence, and type I and type II lacto-series sugar chain, respectively. C/Ann Arbor/1/50 reacted only with 9-O-Ac-Neu5Ac-carrying sugar chains in all the gangliosides tested. This method also allowed the microanalysis of receptor gangliosides of unknown samples. ESK cells, sensitive to the influenza A viruses infection, expressed several kinds of receptor active gangliosides, while those from ESK-R cells, resistant to the virus infection, were undetectable.

Signal transduction events whereby PGF2 alpha inhibits the ammoniagenic response to acute acidosis

Subconfluent cultures of LLC-PK1 cells were incubated for 1 h in Krebs-Henseleit buffer (KHB) of pH 7.4 or 6.8 to investigate the signal transduction events associated with prostaglandin F2 alpha (PGF2 alpha) inhibition of ammonia metabolism. Exposure of these cultures to PGF2 alpha (0.1 ng/ml) inhibited the acute low pH stimulation of ammonia production and to a lesser degree alanine formation in a manner analogous to the response exhibited with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA). Pretreatment with an inhibitor of protein kinase C [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine, i.e., H-7] or utilization of cultures with downregulated protein kinase C activity abolished the inhibitory response to PGF2 alpha. Exposure to PGF2 alpha for 10 min in KHB of pH 6.8 resulted in an activation of protein kinase C, as demonstrated by a significant increase in membrane-bound enzyme activity. Incubation of the cells with PGF2 alpha in KHB of pH 6.8 also resulted in a significant increase in inositol trisphosphate formation. Treatment of the cultures with verapamil in calcium-containing medium or removal of calcium from the incubating medium resulted in a significant loss of the PGF2 alpha inhibitory response on both ammonia and alanine production. Furthermore, under conditions of calcium-free incubation, PGF2 alpha had no significant effect on protein kinase C activity. Because both PGF2 alpha- and TPA-induced inhibition of ammoniagenic response to acute acidosis was prevented by amiloride, the underlying mechanism may involve protein kinase C-mediated changes in intracellular pH. These results indicate that the activation of protein kinase C plays a key role in mediating PGF2 alpha inhibition of ammoniagenesis.

Glycocholic acid and glycodeoxycholic acid but not glycoursocholic acid inhibit bile acid synthesis in the rabbit

Feedback regulation of derepressed hepatic bile acid biosynthesis was studied individually with glycocholic, glycodeoxycholic, and glycoursocholic acids by infusion into bile acid-depleted rabbits. Construction of a bile fistula drained the endogenous bile acid pool (90% glycodeoxycholic acid, 10% glycocholic acid) within 24 hours and elicited maximal bile acid synthesis after about 72 hours, at which time glycocholic acid became the only biliary bile acid (greater than 98%). Replacement of the bile acid pool with glycocholic acid or glycodeoxycholic acid at a rate equivalent to the hepatic endogenous bile acid flux inhibited endogenous biosynthesis by 40%. In contrast, glycoursocholic acid, the 7 beta-hydroxy epimer of glycocholic acid, failed to suppress synthesis. Hepatic bile acid depletion increased hydroxymethyglutary coenzyme A (HMG-CoA) reductase activity fourfold and cholesterol 7 alpha-hydroxylase activity threefold, which were reduced 48% and 51%, respectively, from their maximum levels during replacement with glycocholic acid. Glycodeoxycholic acid infusion depressed cholesterol 7 alpha-hydroxylase activity by 59% without reducing HMG-CoA reductase activity significantly. There was no significant change in the activity of either enzyme during glycoursocholic acid infusion. Biliary cholesterol and cholestanol secretion declined 13% and 53%, respectively, during glycocholic acid infusion, were not affected by glycodeoxycholic acid infusion, but increased 19% and 43%, respectively, during glycoursocholic acid infusion. These results show that in rabbits the feedback regulation of hepatic bile acid synthesis depends on the hepatic flux of the normally present endogenous bile acids glycocholic acid and glycodeoxycholic acid but does not respond to the 7 beta-hydroxy glycoursocholic acid. Glycocholic acid inhibits both HMG-CoA reductase and cholesterol 7 alpha-hydroxylase while glycodeoxycholic acid affects primarily cholesterol 7 alpha-hydroxylase. Thus, the regulation of bile acid synthesis may be mediated by both the availability of cholesterol substrate and the activity of the rate-determining enzyme for bile acid synthesis.

Human intestinal mucin-like protein (MLP) is homologous with rat MLP in the C-terminal region, and is encoded by a gene on chromosome 11 p 15.5

A cDNA specific for a human intestinal mucin (MLP) was amplified by PCR from cDNA of cultured human colonic adenocarcinoma cells, LS174T. The human cDNA shared high sequence homology with a corresponding rat intestinal mucin (MLP) cDNA in the 3' terminal region, and hybridized to the same mRNA (approximately 9.0 Kb) that was recognized by a probe for the MUC-2 human intestinal mucin gene. The gene encoding our human mucin peptide also mapped to chromosome 11 p 15.5, the known locus of MUC-2. Our findings suggest that human MLP and MUC-2 are encoded by the same gene and that rat and human intestinal mucin share a common C-terminal amino acid structure.

cDNA for the carboxyl-terminal region of a rat intestinal mucin-like peptide

When subjected to thiol reduction, purified intestinal mucins have been shown to undergo a decrease in molecular mass and to liberate a 118-kDa glycopeptide (Roberton, A. M., Mantle, M., Fahim, R. E. F., Specian, R., Bennick, A., Kawagishi, S., Sherman, P., and Forstner, J. F. (1989) Biochem. J. 261, 637-647). The latter has been called a putative "link" component because it is assumed to be important for disulfide bond-mediated mucin polymerization. Controversy exists as to whether the putative link is an integral mucin component or a separate mucin-associated glycopeptide. In the present study both NH2-terminal and internal amino acid sequences of the 118-kDa glycopeptide of rat intestinal mucin were used to generate opposing oligonucleotide primers for polymerase chain reaction. A specific 1.2-kilobase (kb) product was obtained, from which a 0.5-kb HindIII fragment was used as a probe to screen a lambda ZAP II cDNA library of rat intestine. A 2.6-kb cDNA (designated MLP 2677) was sequenced and revealed an open reading frame of 2.5 kb encoding 837 amino acids. The deduced amino acid sequence showed that the putative link peptide is equivalent to the carboxyl-terminal 689 amino acids of a larger peptide. Northern blots revealed a mRNA size of approximately 9 kb. Computer searches revealed no sequence homology with other proteins, but similarities were seen in the alignment of cysteine residues in the link and in several domains of human von Willebrand factor, as well as cysteine-rich areas of bovine and porcine submaxillary mucins and a frog skin mucin designated FIM-B.1. In keeping with earlier demonstrations of the presence of mannose in the 118-kDa glycopeptide, there were several (13) consensus sequences for attachment of N-linked oligosaccharides within the link domain. Further sequencing of MLP 2677 in a direction 5' to the codon specifying the NH2-terminal proline of the link has revealed a coding region for 148 amino acids, including a unique 75-amino acid domain rich in cysteine and proline, and a region containing 4.5-variable tandem repeats (each 11-12 amino acids) rich in serine, threonine, and proline. The presence of mucin-like tandem repeats suggests that the entire cysteine-rich link peptide represents the carboxyl-terminal region (75.5 kDa) of a mucin-like peptide (MLP). The latter is estimated to have a molecular mass of approximately 300 kDa.

[Quality of tuberous root of Liriope spicata (Thunb.) Lour. var. prolifera Y.T.Ma and Ophiopogon japonicus (L.F.) Ker-Gawl.--comparison of immune function]

This paper deals with comparative study on the immune function of the tuberous root of Liriope spicata var. prolifera and Ophiopogon japonicus. The results showed that the aqueous extract of both species mentioned above could increase obviously the spleen weight (immunity organ) of mice, enhance the clearance rate of iv charcoal particles in mice and antagonize remarkably the leukopenia caused by cyclophosphamide.

[Studies on the quality of fructus Cnidii--comparison of antibacterial action]

Comparative studies on antibacterial and antifungal action of the fruits of C. monnieri from four habitats and two other species of Cnidium showed they had inhibitory potency to some bacterial and fungi in vitro. C. monnieri and C. salium were more effective than C. dahuricum in antibacterial activities. C. monnieri had higher antifungal effect than C. salium and C. dahuricum.

[Textual and herbal studies on shashen and qini (Adenophora spp.)]

This paper reports the origins of the Chinese traditional drugs nanshashen and beishashen, as well as the original plants of shashen, xingyeshashen, xiyeshasen and qini recorded in the bencaological works of the past dynasties. Our study shows that shashen is Adenophora stricta, both xingyeshashen and qini are A. hunanensis and xiyeshashen is A. paniculata.

[Survey of an outbreak of mycoplasmal pneumonia firstly discovered in Zhejiang Province]

An exceptional outbreak of mycoplasmal pneumonia in a factory of prisoners, Juzhou city, Zhejiang province, during November to December, 1985 was reported. In the course of the epidemic 102 cases were infected, with an attack rate of 3.3 per cent, but the attack rate in the outbreak point was 29.1 per cent. All cases were not dead. This outbreak was diagnosed as mycoplasmal pneumonia by clinical observation, X ray examination serological test and epidemiological survey. The sources of infection were 3 sporadic patients. The epidemic was quickly controlled by using comprehensive preventive measures.

[Investigation on resources of the Chinese drug beimu in Gansu Province]

Based on a resources investigation and taxonomic research on the medicinal plants of Fritillaria from Gansu Province. Nine species one variety and one cultivation variety have been reported. Records and distribution of the species, together with a key for the species and a key for the powdered drug have been furnished as well.

[Various methods for purification of urine Tamm-Horsfall protein]

The measurements of serum, urine Tamm-Horsfall protein (THP) and its antibody are essential to the early diagnosis of tubulointerstitial diseases and acute rejection after renal transplantation. The purification of THP proves to be the key procedure for the production of diagnostic kit. Once, twice and three times salt precipitation with 0.58 mol/L NaCl and chromatography with Sephadax G-200 were adopted to purify urine THP. Enzyme immunoassay was used to detect the antigenicity of the products, SDS-PAGE to determine the molecular weight (MW) and the electrophoretic purity (EP), Beckman DU-7 model spectrophotometer to scan the ultraviolet absorption spectrum. Evaluation of the four methods was based on the purity and the antigenicity of the produced THP, the output, the complexity of procedure, and the cost of required materials. Results show that the MW of THP is 93.0 kd; the ultraviolet absorption maximum is at lambda = 278 nm; the outputs are 7.5, 5.5, 3.8, and 0.4 mg/L; the concentrations of THP with antigenicity are 65%, 75%, 98% and 100%, respectively, and the EPs of three times salt precipitation and chromatography are better. It is concluded that three times salt precipitation should be recommended because of its excellence in purity and antigenicity of the produced THP, the simplicity of manipulation, and the cheapness of the materials needed.

Deletions and a translocation interrupt a cloned gene at the neurofibromatosis type 1 locus

Three new neurofibromatosis type 1 (NF1) mutations have been detected and characterized. Pulsed-field gel and Southern blot analyses reveal the mutations to be deletions of 190, 40, and 11 kb of DNA. The 11 kb deletion does not contain any of the previously characterized genes that lie between two NF1 translocation breakpoints, but it does include a portion of a rodent/human conserved DNA sequence previously shown to span one of the translocation breakpoints. By screening cDNA libraries with the conserved sequence, we identified a number of cDNA clones from the translocation breakpoint region (TBR), one of which hybridizes to an approximately 11 kb mRNA. The TBR gene crosses at least one of the chromosome 17 translocation breakpoints found in NF1 patients. Furthermore, the newly characterized NF1 deletions remove internal exons of the TBR gene. Although these mutations might act by compromising regulatory elements affecting some other gene, these findings strongly suggest that the TBR gene is the NF1 gene.

[Analysis of essential oils in roots and fruits of Angelica in Northeast China]

The essential oils of roots and fruits of five species of Angelica have been examined and analysed by GC-MS-DS; 59 chemical compounds are reported, of which alpha-pinene, myrcene and p-cymene are common to all five species. This paper provides a scientific basis for developing the resources of this genus in the Northeast.

[Studies on blood galactokinase of patients with presenile and senile cataracts]

Whole blood galactokinase (GK) activities were determined in 278 individuals including 77 patients with senile cataracts, 60 with presenile cataracts and 141 normal controls. No significant difference was found among the GK levels of the three groups. The frequency of GK heterozygocity in the presenile cataract group, however, was significantly higher than that in the normal control group (P less than 0.01), suggesting that even a partial decrease in GK activity might facilitate cataract formation in relatively early stages of life. The intake of milk and its products should be limited, both in GK homo- and heterozygotes.

[Chemical constituents of Isodon parvifolia (Batalin) Hara]

Twelve compounds were isolated from the leaves and stems of Isodon parvifolia. This paper deals with the isolation and identification of two diterpenes epinodosinol (I), lasiodonin (II) and two triterpenes alpha-amyrin (XI a) and beta-amyrin (XI b).

[Analgesic and sedative effects of the Chinese drug rhizoma Paridis]

The analgesic and sedative actions of Chinese drug Rhizoma Paridis are reported. All of the 6 experimented species and varieties in common use are obviously effective. Among them Paris polyphylla var. chinensis, P. polyphylla var. yunnanensis are stronger in analgesic action. Sedative action of P. fargesii, P. polyphylla var. chinensis, P. thibetica is also strong. In addition, pariphyllin A and gracillin were also used in the experiment.