Chromosomal drift, a new phenomenon in plants.

A seasonal shift in chromosome number of reproductive cells of Claytonia virginica, which coincided with near-drought conditions, resulted in a chromosome complement new to the population. The number reappeared 2 years later, the minimum time required for plants of that generation to produce flowers. Moreover, the chromosome number of root cells commonly differed from aerial organs of the same plant.

Multiple Genotypes in Individuals of Claytonia virginica.

Supernumerary chromosomes are common among plants of Claytonia virginica found in a weedy population near the southwestern edge of its distribution. Roots, stems, and microsporocytes vary in chromosome number within the same plant in 68 percent of the population studied.

Chromosome-mediated gene transfer of hydroxyurea resistance and amplification of ribonucleotide reductase activity.

Metaphase chromosomes purified from a hydroxyurea-resistant Chinese hamster cell line were able to transform recipient wild-type cells to hydroxyurea resistance at a frequency of 10(-6). Approximately 60% of the resulting transformant clones gradually lost hydroxyurea resistance when cultivated for prolonged periods in the absence of drug. One transformant was subjected to serial selection in higher concentrations of hydroxyurea. The five cell lines generated exhibited increasing relative plating efficiency in the presence of the drug and a corresponding elevation in their cellular content of ribonucleotide reductase. The most resistant cell line had a 163-fold increase in relative plating efficiency and a 120-fold increase in enzyme activity when compared with the wild-type cell line. The highly hydroxyurea-resistant cell lines had strong electron paramagnetic resonance signals characteristic of an elevated level of the free radical present in the M2 subunit of ribonucleotide reductase. Two-dimensional electrophoresis of cell-free extracts from one of the resistant cell lines indicated that a 53,000-dalton protein was present in greatly elevated quantities when compared with the wild-type cell line. These data suggest that the hydroxyurea-resistant cell lines may contain an amplification of the gene for the M2 subunit of ribonucleotide reductase.

Amplification of N-myc and ornithine decarboxylase genes in human neuroblastoma and hydroxyurea-resistant hamster cell lines.

The genes for the M2 subunit of ribonucleotide reductase (RRM2), ornithine decarboxylase (ODC1), and 55,000-Daltons protein (P5), are amplified in hydroxyurea-resistant hamster and human cell lines. These genomic sequences have been mapped to hamster chromosome 7 and to human chromosome 2p24-25 near the cytogenetic location of the N-myc gene. We now report that genomic sequences homologous to N-myc are amplified in hydroxyurea-resistant hamster lung cell line, 600H, and the N-myc gene segregates with hamster chromosome 7 in mouse-hamster somatic cell hybrids. The conserved linkage group consisting of the RRM2, ODC1, P5, and N-myc in the hamster and human genomes prompted our investigation of human neuroblastomas. We report here that genomic DNA from 1 of 6 primary neuroblastoma tumors containing amplified N-myc also contains amplified sequences homologous to a hamster ODC cDNA.

Human Ia molecules carrying MT1 determinants: purification with a monoclonal antibody.

A monoclonal antibody 77.34, reactive with polymorphic HLA class II molecules, was produced. The allotype specificity of this IgG2a antibody was analyzed by cytotoxicity, flow cytometry, and cellular radioimmunoassay. Cytotoxic reactivity on a panel of B cells from 88 unrelated individuals was concordant with the MT1 (DC1) allospecificity (r = 0.83). Immunoanalysis by flow cytometry showed that cells from MT1+ homozygous cell lines were reactive, whereas MT2+ and MT3+ homozygous cells were not. A cellular radioimmunoassay performed under saturating conditions indicated that three MT1+ cell lines bound 14-45 X 10(5) molecules of antibody per cell representing 30-40% of the amount detected with monomorphic anti-DR monoclonal antibody 21w4. The subset of molecules bearing the MT1 allospecificity was purified with a 77.34 IgG immunoadsorbent. The purified molecules were antigenically reactive with several antibodies directed at DQw1 molecules but were devoid of reactivity to monomorphic anti-DR antibodies. Two-dimensional gel electrophoresis showed that the alpha subunit is composed of several acidic spots of Mr 32,000 whereas the beta subunit was seen as a single spot of Mr 25,000, corresponding to DQw1 molecules. DR molecules purified by monoclonal antibody affinity were unreactive with 77.34 antibody. All of the 77.34 reactivity was observed with the fractions depleted of DR molecules. Two-dimensional gel analysis showed marked differences between the purified DR and DQw1 molecules. The presence of the MT1 determinant on Ia molecules referred to as the DQw1 molecules and distinct from those bearing the DR epitopes was confirmed on two DR1, MT1 homozygous cell lines. Thus, DQw1 molecules can be purified away from DR1 molecules by affinity chromatography to 77.34 IgG, specifically reactive with the MT1 (DQw1) allospecificity. The binding of 77.34 IgG to MT1+ cells was not inhibited by all monoclonal antibodies reported to be correlated with the MT1 allospecificity suggesting that the latter might be comprised of more than a single epitope.

Duplex PCR system for simultaneous detection of Neisseria gonorrhoeae and Chlamydia trachomatis in clinical specimens.

AIMS: To evaluate the use of a duplex polymerase chain reaction (PCR) assay for the simultaneous detection of Neisseria gonorrhoeae and Chlamydia trachomatis in clinical samples. METHODS: Genital swab specimens were obtained from both China (203 swabs) and Hong Kong (202 swabs). N gonorrhoeae and C trachomatis were detected in each specimen with a number of tests including enzyme immunoassays (IDEIA) and PCR assays using both single and double primer pairs. The primer pair for N gonorrhoeae was derived from the cppB gene on its cryptic plasmid and the PCR product was 390 base pairs long. For C trachomatis, the PCR product was 473 base pairs long, resulting from amplification of a sequence in the common 7.4 kilobase plasmid present in all serovars. For N gonorrhoeae, PCR results were also compared with those obtained by culture and Gram's smear of the discharges. RESULTS: For the 203 specimens collected in China, similar numbers of positive results (177) were obtained by both Gonozyme and duplex PCR for the detection of N gonorrhoeae. No discrepant results were found among the cultured specimens when Gonozyme and duplex PCR were compared. C trachomatis was detected in 47 specimens by duplex PCR, but was detected in only 28 by IDEIA. Of the 202 Hong Kong specimens, 46 were positive for N gonorrhoeae, detected by both Gonozyme and duplex PCR; 34 were positive for C trachomatis, 25 of which were detected by IDEIA and the remainder by duplex PCR. CONCLUSIONS: The duplex PCR assay is a satisfactory diagnostic tool for the simultaneous detection of N gonorrhoeae and C trachomatis in clinical swab samples. Further evaluation is suggested.

Analysis of charge of kappa and lambda chain-containing serum immunoglobulin A by immunoblotting and densitometry.

A novel method for studying the charge distribution of different subclasses of serum immunoglobulin A (defined by the light chains) is described. Affinity-chromatography purified immunoglobulins were focused in polyacrylamide gel and were then transferred electrophoretically onto nitrocellulose membranes. The transferred immunoglobulins were detected by rabbit antiserum to human kappa (kappa) or lambda (lambda) chain, swine antirabbit IgG, rabbit anti-peroxidase antibodies and peroxidase, together with a substrate solution comprising H2O2 and diaminobenzidine. Finally, the developed membranes were made transparent with Triton-x 114, scanned at 485 nm with a densitometer to obtain quantitation of charge distribution.

Hypertrophic scar: a genetic hypothesis.

Two groups of patients with surgical and thermal wounds respectively were tested for aldehyde dehydrogenase 2 deficiency and assessed for the degree of hypertrophy of their scars. No association was found between the deficiency and hypertrophy of the scar. The frequency of hypertrophy was found to be 0.914 in the thermal injury group and 0.446 in the surgical wound group. This difference is statistically significant. The frequency data of the degree of hypertrophy in the two groups has been used to develop and test a single gene hypothesis for the origin of hypertrophic scar in the local Chinese population. It is postulated that the allele responsible for hypertrophy behaves as a dominant allele in the thermal injury group and as a recessive in the surgical wound group for the induction of hypertrophy.

No association found between C3 alleles and scar hypertrophy.

Serum C3 was examined for structural variants using high-voltage agarose gel electrophoresis at both pH 6.2 and 8.4, thermal stability and stability to attack by hydroxyl radicals, in 450 Chinese people in Hong Kong. The C3 allele frequencies for electrophoretic variants were found to be 0.9911 for C3 *S and 0.0089 for all other rare alleles. No variants were found in terms of stability at 54 degrees C in the absence of Ca2+ or at 62 degrees C in the presence of Ca2+, and in terms of stability to attack by hydroxyl radicals. Based on a recently proposed single gene hypothesis for scar hypertrophy, statistical analyses were carried out to compare the relevant frequency data of scar hypertrophy with C3 phenotype frequencies, both for the local Chinese population and a European Caucasian population. There is no evidence for any association between C3 alleles or phenotypes and the formation of hypertrophic scars.

A longitudinal study of C3, C3d and factor Ba in burn patients in Hong Kong Chinese.

A longitudinal study of serum C3, C3d and fragment Ba was carried out in 53 burn patients of Chinese origin whose total burn surface area ranged from I to 45%. Complement C3 was found to be activated on or before day 7 post-burn. The sharp increase in C3d suggested an acute inflammatory response. In addition factor Ba was increased in these patients, suggesting that the alternative pathway was also activated following thermal injuries. The fluctuations of C3, C3d and Factor Ba observed about 1 year after injury suggested chronic inflammation associated with long term of outcome of healing in the burn sites.

No adaptogen response of mice to ginseng and Eleutherococcus infusions.

There was no significant difference in mortality, weight gain, liquid consumed, or pathogenesis between mice ingesting four different ginseng infusions for up to 96 days, and control mice drinking distilled water. These results suggest no toxicity or tea selectivity of mice subjected to such regimens. Mice that drank concentrated Siberian ginseng wuchaseng extract with sugar showed significantly more aggressive behavior than those drinking other infusions or distilled water. However, there was no significant difference in stamina or longevity between mice drinking infusions of two preparations of Siberian ginseng, Oriental ginseng, or American ginseng, and control mice when subjected to swimming trials in cold water 38, 46 and 96 days after treatment began. Consequently, ingestion of adaptogenic glycosides did not significantly affect the survival of mice under major environmental stress.

Ritualistic use of the holly Ilex guayusa by Amazonian Jívaro Indians.

In Amazonian Peru and Ecuador leaf decoctions of the rainforest holly Ilex guayusa with high caffeine concentrations are used as a morning stimulant. After daily ingestion, ritualistic vomiting by male Achuar Indians, better known as Jívaros, reduces excessive caffeine intake, so that blood levels of caffeine and biotransformed dimethylxanthines do not cause undesirable CNS and other effects. Emesis is learned and apparently not due to emetic compounds.

The blood composition of different breeds of bulls undergoing beef performance tests.

Blood samples taken on three occasions from each of 66 bulls undergoing beef performance tests were analysed for packed cell volume, blood glucose, haemoglobin, serum albumin, urea nitrogen, total protein, inorganic phosphate, Ca, Ca, Mg, K, Na, Cu, Fe and total iron binding capacity. The bulls were individually fed and situated at two centres, one accommodating Lincoln-Red, Devon and Sussex breeds and the other, Hereford. Significant differences between the Lincoln-Red, Devon and Sussex breeds were observed in concentrations of glucose, urea nitrogen, total iron binding capacity (P less than 0.001), Ca (P less than 0.01), Na and Cu (P less than 0.05). There were no significant correlations between the growth rates of individual bulls and their blood composition.

C3d levels in normal individuals of Chinese origin.

The level of C3d in the urine and serum of normal healthy Chinese individuals was determined by enzyme-linked immunoassay. Urine levels were found to be in the range of 0.1-2.3 ng/mmol/l creatinine (n = 87, mean = 0.242 microgram /ml). Serum levels were in the range of 10.1-37.6 micrograms/ml (n = 30, mean = 22.6 micrograms/ml). C3d clearance was also determined in 10 selected normal healthy individuals with random urine levels in the upper, middle and lower range. Results suggest that there may be individual variability in the way in which C3d is cleared from blood in normal individuals and it is suggested that caution is necessary in interpreting single urine C3d estimations.

Circulating immune complexes of xanthine oxidase in normal subjects.

An antigen-specific enzyme-linked immunosorbent assay (ELISA) was developed to detect immune complexes of xanthine oxidase (XODIC), and applied to assay serum XODIC in normal subjects. It was found that XODIC of both IgM and IgG isotypes could be detected in all the 85 sera tested. XODIC levels as a percentage of total xanthine oxidase antibody (XODAb) in the free and bound forms were mostly less than 20%, and there was also significant correlation in XODIC and XODAb levels for both IgM and IgG isotypes. The implications of these findings are discussed.

Study of free iron and pyridinoline in hypertrophic scars and normal skin.

In order to investigate the possible involvement of free radicals in the formation of hypertrophic scar, normal skin sections were subjected in vitro to a free radical generating system and the pyridinoline levels determined by enzyme-linked immunoassay. Pyridinoline concentration increased from 5.123 pmol/mg wet weight to 8.760 pmol/mg wet weight after treatment with a free radical generating system. Free iron, a catalyst for the generation of hydroxyl radicals from hydrogen peroxide, was found to be significantly higher in hypertrophic scar tissue (n = 6, mean 50.70 ng/mg wet weight) compared to normal skin (n = 12, mean 7.89 ng/mg wet weight, P = 0.0093, unpaired t-test). It is hypothesised that the occurrence of increased pyridinoline cross-links in hypertrophic scar tissue may result from free radical generation related to inflammatory processes. Further work is necessary to test this hypothesis, but these results suggest that it is tenable.

Diagnosis of urogenital gonorrhoea: evaluation of an enzyme immunoassay and use of urine as a non-invasive specimen.

Urethral swabs and urine samples were collected from 42 male patients attending a social hygiene clinic in Hong Kong and used for gonococcal culture and detection of antigens by enzyme immunoassay. Of the patients, 21 were suffering from gonorrhoea as indicated by positive gonococcal culture from both urethral swabs and urine. Twenty of the positive cases were detected by both swab and urine specimens using Gonozyme, an enzyme immunoassay kit. One culture-positive case failed detection by both swab and urine specimens. Gonozyme showed sensitivity and specificity of 95.2% and 100% respectively. With male patients, the use of urine as an alternative specimen to urethral swabs appears to have potential value for both culture and Gonozyme testing. Genital swabs and urine samples were subsequently collected from 108 patients (89 male, 19 female) attending the sexually transmitted disease monitoring centre in Guangzhou, China. Gonozyme tests were performed on both types of specimen, while only swabs were cultivated. When compared with swab culture, Gonozyme had sensitivity and specificity of 100% and 89.2% for males, and 100% and 90.9% for females, respectively. When urine was compared with swabs in the Gonozyme test, urine had sensitivity and specificity of 83.6% and 89.2% for males, and 62.5% and 81.8% for females, respectively. Hence, Gonozyme merits further investigation as an acceptable rapid diagnostic method for detection of Neisseria gonorrhoeae, especially when using urine as an alternative non-invasive specimen from male patients.

Cinchonicine-derived alkaloids from the bark of the Peruvian Ladenbergia oblongifolia.

The isolation of cinchonicine-derived alkaloids epicinchonicinol (1), cinchonidicinol (2) and a mixture of dihydrocinchonicinol and dihydrocinchonidicinol (3) from the dried bark of Ladenbergia oblongifolia, is reported along with (1)H and (13)C-NMR data.