Association of a retroelement with a P4-like cryptic prophage (retronphage phi R73) integrated into the selenocystyl tRNA gene of Escherichia coli

A new multicopy single-stranded DNA (msDNA-Ec73) was found in a clinical strain of Escherichia coli. Retron-Ec73, consisting of an msDNA-coding region and the gene for reverse transcriptase (RT), was found to be a part of a 12.7-kb foreign DNA fragment flanked by 29-bp direct repeats and integrated into the gene for selenocystyl-tRNA (selC) at 82 min on the E. coli chromosome. Except for the 2.4-kb retron region, the integrated DNA fragment showed remarkable homology to most of the bacteriophage P4 genome. Among the phage genes found in this element, however, the integrase gene had very low identity (40%) to P4 integrase, indicating that the cryptic prophage associated with the retroelement has its own unique site-specific integrase different from P4 integrase. Recently, we have shown that P2 phage can act as a helper to excise the cryptic prophage and to package its genome into an infectious virion. The newly formed phage (retronphage phi R73) can also lysogenize a new host strain, reintegrating its genome into the selC gene and enabling the newly formed lysogen to produce msDNA-Ec73 (S. Inouye, M. G. Sunshine, E. W. Six, and M. Inouye, Science 252:969-971, 1991).

Acetylcholine receptor-reactive T and B cells in myasthenia gravis and controls

Myasthenia gravis (MG) is strongly associated with antibodies to acetylcholine receptor (AChR), whereas the extent of T cell involvement is not settled. The number of cells secreting interferon-gamma (IFN-gamma) in response to AChR during 48 h culture of blood mononuclear cells (PBL) may reflect AChR-reactive T cells. Using an immunospot assay, we detected such cells in 23 of 30 patients with MG at a mean number of 1 per 33.333 PBL. AChR-reactive T cells were also found in patients with other neurological diseases (OND) and in healthy subjects but at lower frequencies and numbers. The T cell response to purified protein derivative and to PHA, and also to two major myelin proteins (basic protein and proteolipid protein) did not differ between MG and the two control groups, underlining the specificity of an augmented T cell reactivity to AChR in MG. Evaluation of the B cell response by enumerating anti-AChR IgG antibody secreting cells revealed such cells in 27 of 28 patients with MG at a mean value of 1 per 14,085 PBL. Cells secreting anti-AChR antibodies of the IgA and IgM isotypes were also detected in MG, but less frequently, at lower numbers, and only in conjunction with IgG antibody secreting cells. Anti-AChR antibody secreting cells were also found among patient with OND and in healthy controls, but at lower frequencies and numbers. These data confirm that AChR is a major target for autoimmune response in MG.

The association between cervical carcinoma and human papilloma virus (HPV) in Xiangyuan County

A mass survey was conducted to investigate the association between cervical carcinoma and human papilloma virus (HPV) infection in a high-risk area, Xiangyuan County, Shanxi Province. Fifty-four cases of cervical cancer in situ (CIS), including severe dysplasia (CIN III), 14 cases of invasive cervical carcinoma, 28 cases of mild cervical dysplasia (CIN I), and 13 cases of moderate cervical dysplasia (CIN II) were identified among 6710 women examined. One hundred and sixty-nine punch biopsies from abnormal cervix and genital tract were examined for the presence of HPV 6B/11, 16 and 18 DNA sequences by dot blot hybridization: The positive rates of HPV infection in cervicitis, CIN I, II, III, CIS and invasive cervical carcinoma specimens were 35.06% (27/77), 25% (2/8), 33.33% (2/6), 40% (2/5), 70.58% (24/34) and 40% (4/10), respectively. Among these groups, there was no regular distribution of HPV types except for HPV 16, the positive rate of which was increased from 25% in CIN I to 46.15% in CIS: HPV 16 was also the only type seen in the invasive cervical cancer group. Distribution analysis of HPV types in HPV-positive cervical cancer tissues uncovered an HPV 16 positive rate of 59.4%; 3.7 and 2.4 times higher than those of HPV 6B/11 and HPV 18, respectively. These data confirm the close association between cervical cancer and HPV 16 infection.

Cord blood contains cells secreting antibodies to nervous system components

Umbilical cord blood of newborns and peripheral blood of healthy adults were investigated by an immunospot assay for cells secreting IgG, IgA and IgM antibodies against myelin basic protein (MBP), proteolipid protein (PLP), myelin-associated glycoprotein (MAG) and myelin oligodendrocyte glycoprotein (MOG) which represent putative antigens for an autoimmune attack in multiple sclerosis (MS) and against acetylcholine receptor (AChR) which is considered an important autoantigen in myasthenia gravis. Cells secreting antibodies against one or more of these autoantigens were detected in 18 out of 24 newborns, and in eight out of 20 adults. Eight of the cord blood samples contained cells secreting antibodies of IgG, IgA and/or IgM isotypes to one antigen, five to two antigens, two to three antigens, two to four antigens, and one to five antigens. Most prominent were anti-MBP IgG antibody secreting cells which were detected in 13 newborns at a mean number of 1/20,000 cord blood cells, and in six adults at a mean number of 1/10(5) peripheral blood cells. Anti-AChR IgG antibody secreting cells were detected in four out of 12 newborns versus four out of 14 peripheral blood specimens, at mean values of 1/10(5) cells in both instances. Cells secreting autoantibodies of IgA and IgM isotypes were less frequent both in cord blood and peripheral blood. The occurrence of nervous tissue autoantibody secreting cells in newborns must be related to a possible primary role of such autoantibodies in MS and myasthenia gravis.

T and B cell responses to myelin-oligodendrocyte glycoprotein in multiple sclerosis

The pathogenesis of multiple sclerosis (MS) is believed to involve an autoimmune component directed against the myelin sheath. One potential target Ag for such autoimmune attack is the myelin-oligodendrocyte glycoprotein (MOG) because an anti-MOG mAb has profound influence on the course of experimental autoimmune encephalomyelitis, which to some extent represents an experimental model of MS. Using single cell assays, we have evaluated T and B cell reactivities to MOG in MS patients and controls. T cell reactivity was estimated by counting the number of cells that secreted IFN-gamma in response to MOG, whereas B cell reactivity was estimated by enumerating cells secreting antibodies that bound to MOG. MOG reactive T cells were detected in the peripheral blood of the majority of the 16 MS patients examined (mean 1/7299 mononuclear cells), but infrequently and at lower numbers in samples from neurologic controls. MOG-reactive T cells were more frequent among MS patients' cerebrospinal fluid (CSF) mononuclear cells (mean 1/450 cells). The T cell response to MOG was evidently MHC class II restricted, because Fab fragments of a rabbit polyclonal anti HLA-DR antibodies abrogated the Ag-induced increase in number of cells that secreted IFN-gamma, as analyzed on CSF and PBMC from three patients with MS. Anti-MOG IgG antibody-secreting cells were detected in blood in 8 of 16 MS patients (mean 1/25,641 cells), but they were also strongly accumulated in CSF, being detected in 8 of 10 MS patients examined (mean 1/265 cells), while rarely found in controls. The findings imply that MOG may represent a pathogenetically important target Ag in MS.

T and B cell responses to myelin-oligodendrocyte glycoprotein in multiple sclerosis

The pathogenesis of multiple sclerosis (MS) is believed to involve an autoimmune component directed against the myelin sheath. One potential target Ag for such autoimmune attack is the myelin-oligodendrocyte glycoprotein (MOG) because an anti-MOG mAb has profound influence on the course of experimental autoimmune encephalomyelitis, which to some extent represents an experimental model of MS. Using single cell assays, we have evaluated T and B cell reactivities to MOG in MS patients and controls. T cell reactivity was estimated by counting the number of cells that secreted IFN-gamma in response to MOG, whereas B cell reactivity was estimated by enumerating cells secreting antibodies that bound to MOG. MOG reactive T cells were detected in the peripheral blood of the majority of the 16 MS patients examined (mean 1/7299 mononuclear cells), but infrequently and at lower numbers in samples from neurologic controls. MOG-reactive T cells were more frequent among MS patients' cerebrospinal fluid (CSF) mononuclear cells (mean 1/450 cells). The T cell response to MOG was evidently MHC class II restricted, because Fab fragments of a rabbit polyclonal anti HLA-DR antibodies abrogated the Ag-induced increase in number of cells that secreted IFN-gamma, as analyzed on CSF and PBMC from three patients with MS. Anti-MOG IgG antibody-secreting cells were detected in blood in 8 of 16 MS patients (mean 1/25,641 cells), but they were also strongly accumulated in CSF, being detected in 8 of 10 MS patients examined (mean 1/265 cells), while rarely found in controls. The findings imply that MOG may represent a pathogenetically important target Ag in MS.

[Differentiation of Magnolia denudata Desr. flower buds]

The article gives the results of an observation on the differentiation of Magnolia denudata buds. In Huaining County, Anhui Province, differentiation of the buds starts at the beginning of May. By the end of June the differentiation of various parts of the flower is completed. The process takes about 50 days. The differentiation of buds goes on at a fairly fast speed and in a fairly uniform way. Based on the results of the observation, the authors advise that application of fertilizer, especially the top application should not be late. The beginning of March is a very important time for the development of buds in length and size, and for the final harvest as well. The proper time to pick the flower buds comes when they are fully developed before the perianth appears.

A survey analysis of the status of influent reproductive age women in Shanghai--a survey report

Characteristics of the female transient population of reproductive age in Shanghai, China, are assessed using data from an October 1988 survey. "Not only did this survey supply large quantities of basic data on the floating population for the Shanghai government and related departments, but [it] was also very enlightening for our research into how to make a good job of family planning administration for China's urban-rural floating population."

Prolongation of the yeast life span by the v-Ha-RAS oncogene

The budding yeast Saccharomyces cerevisiae has a finite life span that is defined by the number of times the cell divides. The patterns of expression of certain genes change in a specific manner during the life span, implying that at least some of the manifestations of the ageing process are subject to gene regulation. It has now been determined that the controlled expression of the RAS oncogene in yeast increases the longevity of this organism, indicating that, conversely, a defined alteration in the activity of a single gene can extend this organism's life span. The results suggest that there is a balance between life-span extension and growth arrest when RAS is expressed. Inasmuch as the homologues of RAS in yeast function to integrate cell metabolism with the cell cycle, these studies raise the possibility that this integrative function may also apply to the co-ordination of successive cell cycles during the life span.

[Identification of 10 kinds of Zanthoxylum by pyrolysis GC]

In this paper, pyrolysis GC was applied to differentiate and fingerprint 10 kinds of Zanthoxylum on an OV-101 capillary column. Analytical conditions with this column, operating temperature, pyrolysis time and peak identifications are discussed.

The cyclic voltammetric study of iron-tallysomycin in the absence and presence of DNA

Cyclic voltammetric studies on iron-tallysomycin complexes have been conducted with and without the presence of calf thymus DNA. Fe(II)-TLM samples exhibit a cyclic voltammogram with only a reduction peak at -230 +/- 5 mV vs Ag/AgCl. The addition of DNA substrate causes the shift of this reduction peak to -140 +/- 10 mV vs Ag/AgCl. This large shift in the positive direction implies that the regeneration of Fe(II)-TLM through the reduction of Fe(III)-TLM is facilitated with the aid of DNA. It also implies that the metal-binding/oxygen-activation domain may be directly involved in the formation of iron-tallysomycin-DNA ternary complex. Air oxidation of Fe(II)-TLM produces an activated intermediate with the following CV characteristics, Ipc/Ipa = 0.90; delta E = 65 mV; Ereduction peak = -100 mV vs Ag/AgCl. Addition of DNA abolishes the redox peaks of this voltammogram, signifying inactivation of the activated species through reaction with substrate. Air oxidation of preformed Fe(II)-TLM-DNA complex did not give a discernable cyclic voltammogram, nor did preformed Fe(III)-TLM and Fe(III)-TLM-DNA samples.

Antibody HMB-45 identifies the cells of blue nevi. An immunohistochemical study on paraffin sections

Sixteen cases of blue nevi were investigated using the anti-melanoma specific antibody HMB-45. This antibody has been found to react with junctional but not with intradermal nevus cells, and with fetal and neonatal, but not with adult, melanocytes. Our study shows that HMB-45 also reacts with cells of the blue nevus, a unique type of intradermal nevus. The origin of blue nevus cells is controversial, and the results of this study support the hypothesis that blue nevus cells are not of purely melanocytic or Schwannian origin, but are derived from a precursor cell that has some common features of both melanocyte and Schwann cell.

[Purification and characterization of beta-N-acetyl hexosaminidase from Aspergillus tamarii]

A beta-N-acetylhexosaminidase from mycelium-free culture filtrate of Asp tamarii S215 was purified to PAGE homogenous by ammonium sulfate and polyethylene glycol fractionation precipitation followed by Sephadex G-50 desalt, DEAE-Sephadex A-25 chromatography, hydroxyapatite chromatography and DEAE-Sephadex A-25 rechromatography with 170-fold purification and 24.7% recovery. The ratio of the beta-GlcNAcase and beta-GalNAcase was 2.5 and remained constant throughout the purification. The Mr estimated with concentration gradient PAGE was 140,000 and subunit Mr determined with SDS-PAGE was 72,000, the number of subunit were 2. The pI was 4.2 determined by PAGIEF. The optimum pH was 5.5-6.5 and 5.0-6.0 for beta-GlcNAcase and beta-GalNAcase respectively with stable pH range 5.5-8.3 for both. The optimum temperature was 60 degrees C for beta-GlcNAcase and beta-GalNAcase. The residual activity of beta-GlcNAcase was 52.7% after treated at 50 degrees C for 8 h and it was 44.9% for beta-GalNAcase. The residual activities of both were down to 1% after treated at 62 degrees C for 10 min. The activity was slightly activated by Mn2+ or Fe2+, while strongly inhibited by Hg2+ and slightly by Ag+, Cu2+, Pb2+, Cd2+ or Zn2+. Analyses of amino acids composition showed that the beta-HexNAcase contained about 24.2% acidic amino acids and 14.9% basic amino acids and only 0.6% methionine.

Indoor radon and lung cancer in China

Radon has long been known to contribute to risk of lung cancer, especially in undergound miners who are exposed to large amounts of the carcinogen. Recently, however, lower amounts of radon present in living areas have been suggested as an important cause of lung cancer. In an effort to clarify the relationship of low amounts of radon with lung cancer risk, we placed alpha-track radon detectors in the homes of 308 women with newly diagnosed lung cancer and 356 randomly selected female control subjects of similar age. Measurements were taken after 1 year. All study participants were part of the general population of Shenyang, People's Republic of China, an industrial city in the northeast part of the country that has one of the world's highest rates of lung cancer in women. The median time of residence in the homes was 24 years. The median household radon level was 2.3 pCi/L of air; 20% of the levels were greater than 4 pCi/L. Radon levels tended to be higher in single-story houses or on the first floor of multiple-story dwellings, and they were also higher in houses with increased levels of indoor air pollution from coal-burning stoves. However, the levels were not higher in homes of women who developed lung cancer than in homes of controls, nor did lung cancer risk increase with increasing radon level. No association between radon and lung cancer was observed regardless of cigarette-smoking status, except for a nonsignificant trend among heavy smokers. No positive associations of lung cancer cell type with radon were observed, except for a nonsignificant excess risk of small cell cancers among the more heavily exposed residents. Our data suggest that projections from surveys of miners exposed to high radon levels may have overestimated the overall risks of lung cancer associated with levels typically seen in homes in this Chinese city. However, further studies in other population groups are needed to clarify the carcinogenic potential of indoor radon.

Lanthanide(III)-phosphatidic acid complexes: binding site heterogeneity and phase separation

The luminescent lanthanides are potentially useful probes of cation-induced events involving phospholipid membranes. In this work, the spectroscopic properties of Tb3+, Ce3+ and Eu3+ are shown to be complementary in defining three forms of complex with phosphatidic acid vesicles. Ce3+, in particular, is useful for studying dilute cation-lipid complexes because it has strong excitation bands in the near ultraviolet. In addition to providing a means for detecting chemically distinct forms of lanthanide-lipid complexes, the luminescence can be used to monitor cation-induced lateral segregation. Ce3+ to Tb3+ energy transfer was observed at lanthanide levels as low as 1:1000 Ln3+/phosphatidic acid, indicating clustering or phase separation. Initial clustering occurs on a subsecond timescale, followed by a much slower aggregation continuing for several minutes to hours. Addition of a chelator results in slow release of the lanthanides. In the case of the dioleoylphosphatidic acid complexes, release is bimodal and indicative of cation entrapment; dimyristoylphosphatidic acid complexes exhibit this behavior only at high temperatures. These observations are consistent with the relative tendencies of these two lipids to form the HII phase. This work sets the foundation for experiments designed to determine the size of nucleation sites for cation-induced events such as intramembrane inverted micelle formation and membrane fusion.

[A preliminary report on the investigation of medicinal plant resources in the Liupan Mountains of Ningxia Hui Autonomous Region]

In this paper, 423 species of medicinal plants belonging to 94 families in Liupan Mountains of Ningzia Hui Autonomous Region have been reported, of which 403 species belonging to 79 families are medicinal spermatophytes. The paper may serve as a reference for medical authorities in developing and utilizing plant resources.

Endoscopic versus operative gastrostomy: final results of a prospective randomized trial

This study compared operative gastrostomy (OG) (by surgeons) with endoscopic gastrostomy (PEG) (by physicians) in a prospective randomized fashion to determine whether one technique was superior. PEG (Sachs-Vine) and OG (Stamm) were done using local anesthesia. Patients were assessed for complications, mortality, tube function, and cost. Groups were equally matched for indications and underlying disease. Fifty-seven had OG and 64 had attempted PEG. Complications occurred in 26% of OG patients and 9% died. Complications occurred in 25% of PEG patients and 12% died. Tube feeding was initiated in both groups within a mean of 29 (24 to 72) hours of the gastrostomy placement. OG cost $1675 and PEG $979 to perform. Twenty-one PEG patients required endoscopic tube change which raised their total cost to $1574. We conclude there is no difference between OG (using local anesthesia) and PEG with regard to morbidity, mortality, or tube function. The endoscopic technique does appear to have economic advantage.

Smoking, air pollution, and the high rates of lung cancer in Shenyang, China

A case-control study involving interviews with 1,249 patients with lung cancer and 1,345 population-based controls was conducted in Shenyang, an industrial city in northeastern China, where mortality rates are high among men and women. Cigarette smoking was found to be the principal cause of lung cancer in this population, accounting for 55% of the lung cancers in males and 37% in females. The attributable risk percentage among females is high compared to elsewhere in China, largely because of a higher prevalence of smoking among women. After adjustment for smoking, there were also significant increases in lung cancer risk associated with several measures of exposure to air pollutants. Risks were twice as high among those who reported smoky outdoor environments, and increased in proportion to years of sleeping on beds heated by coal-burning stoves (kang), and to an overall index of indoor air pollution. Threefold increases in lung cancer risk were found among men who worked in the nonferrous smelting industry, where heavy exposures to inorganic arsenic have been reported. The associations with both smoking and indoor air pollution were stronger for squamous cell and small cell carcinomas than for adenocarcinoma of the lung. Risks due to smoking or air pollution were not greatly altered by adjustment for consumption of fresh vegetables or sources of beta carotene or retinol, prior chronic lung diseases, or education level. The findings suggest that smoking and environmental pollution combine to account for the elevated rates of lung cancer mortality in Shenyang.

Association of RFLP of HLA class I genes with Chinese ankylosing spondylitis patients

By serum typing, it is indicated that HLA B27 may be associated with the susceptibility to ankylosing spondylitis (AS). We analyzed DNA restriction fragment length polymorphism (RFLP) in 28 Chinese AS patients and 99 healthy controls, using a 1.4 Kb HLA class I cDNA probe. The results showed that the frequencies of the 8.1 Kb EcoRI, 5.2 Kb EcoRI and 21.9 Kb XbaI fragments were found to be significantly increased in affected patients (P less than 0.0001, P = 0.0015, respectively), but that of 19.2 Kb XbaI fragment was decreased (P = 0.0021). The data suggest that AS may be a polygenic disease; furthermore, B27 and 8.1 Kb EcoRI band may be two different factors responsible for the susceptibility or just in linkage disequilibrium with the susceptible gene(s).