The mode of immigrant settlement in the "help the poor" program

"This paper studies the settlement of the immigrants from the poor areas of China in the aid-the-poor program, which is a government program providing assistance for poor areas of China. The layout and construction of the new immigrant community and the steps necessary for the creation of an immigrant settlement are also discussed in this paper."

Isoprene emission, photosynthesis, and growth in sweetgum (Liquidambar styraciflua) seedlings exposed to short- and long-term drying cycles

Isoprene emissions were studied in one-year old sweetgum (Liquidambar styraciflua L.) seedlings during nine drying-rewatering cycles extending over five months. Each drying cycle lasted to the point of leaf wilting. Growth was essentially stopped in response to the first drying cycle, though seedling survival and capacity to recover turgor on rewatering remained high throughout the entire nine cycles. Photosynthetic rates of leaves were inhibited by the drying treatments. Under severe drought, isoprene emission rates of leaves were also inhibited, though isoprene emission was generally less sensitive to drought than photosynthesis. The lower drought sensitivity of isoprene emission compared with photosynthesis resulted in a higher percentage of fixed carbon lost as isoprene as seedlings became more stressed. During the recovery phase of the drying-rewatering cycles, isoprene emission rates in several seedlings were higher than in well-watered control seedlings. Following the ninth drying-rewatering cycle, sustained daily watering resulted in recovery of isoprene emission rates to control values within four days. Photosynthetic rates only recovered to 50% of control values after seven days. We conclude that the mechanisms regulating photosynthetic rate and isoprene emission rate are differentially influenced by limited water supplies. The results are consistent with past studies that predict a protective role for isoprene emission during stress, particularly protection from excessive leaf temperatures during drought.

[An analysis on therapeutic effects of posterior scleral support operation for treatment of myopia]

OBJECTIVE

The therapeutic effects of modified posterior scleral support operation for treatment of myopia and its operative effect on ocular axial length in high myopia were analyzed.

METHOD

Among 78 cases 151 myopic eyes having undergone this operation and followed for 6-12 months, there were 23 cases (43 eyes) whose mean ocular axial length was compared with that of matched 20 cases (39 eyes) of myopia having undergone radial keratotomy alone and that of matched 19 cases (38 eyes) without any operation.

RESULT

The results showed significant differences.

CONCLUSION

The modified operation is safe, of simple operative procedure and has definite effect on preventing the lengthening of ocular axial length in high myopia.

Pooling blood donor samples to reduce the cost of HIV-1 antibody testing

Accurate, low cost testing of donated blood is a goal of the global effort to reduce the spread of the human immunodeficiency virus (HIV-1). We describe a modified enzyme immunoassay (EIA) method for detecting HIV-1 antibody (anti-HIV-1) in 15-sample pools. In this preliminary study, the modified EIA was as sensitive for detecting weakly seropositive samples, and as specific for testing HIV-1 Western blot-negative or Western blot-indeterminate results, as testing individual samples by the standard EIA. A simulation of field operations was conducted using pools of blood donor samples collected in the United States and in Shanghai, People's Republic of China. Implementation of the modified EIA method and testing 15-sample pools for anti-HIV-1 is a reliable strategy for reducing the cost of large scale testing of donated blood for anti-HIV-1 in areas of low seroprevalence.

Cell surface activation of the erythropoietin receptor by Friend spleen focus-forming virus gp55

The leukemogenic membrane glycoprotein gp55, encoded by Friend spleen focus-forming virus (SFFV), induces erythroid cell proliferation through its interaction with the erythropoietin receptor (EPO-R). There are two forms of gp55 in SFFV-infected cells: an intracellular form (more than 95% of the total protein), which is localized within the endoplasmic reticulum (ER) membranes, and a cell surface form (about 3 to 5%). Because both forms of the viral proteins bind to EPO-R, it is not clear whether the viral protein induces mitogenesis intracellularly or at the cell surface. To address this question, we constructed an EPO-R mutant that contained a 6-amino-acid (DEKKMP) C-terminus ER retention signal. Biochemical and functional analyses with this mutant indicated that it was completely retained in the ER and not expressed at the cell surface. Further analysis showed that the mutant, like the wild-type EPO-R, interacted with SFFV gp55. However, this apparent intracellular interaction between the two proteins failed to induce growth factor-independent proliferation of Ba/F3 cells. Furthermore, spontaneous variants of the ER-retained EPO-R selected on the basis of their ability to induce cell proliferation when coexpressed with gp55 were exclusively expressed at the cell surface. Thus, our results support the hypothesis that the mitogenic activation of the EPO-R by gp55 requires the interaction of the two proteins at the cell surface.

CYP3A gene expression in human gut epithelium

CYP3A4, a major Phase I xenobiotic metabolizing enzyme present in liver, is also present in human small bowel epithelium where it appears to catalyse significant 'first pass' metabolism of some drugs. To determine whether CYP3A4 or the related enzymes CYP3A3, CYP3A5, and CYP3A7 are present in other regions of the digestive tract, we used CYP3A-specific antibodies to examine histological sections and epithelial microsomes obtained from a human organ donor. CYP3A-related proteins were detected in epithelia throughout the digestive tract and in gastric parietal cells, in pericentral hepatocytes, and in ductular cells of the pancreas. Immunoblot analysis suggested that the major CYP3A protein present in liver, jejunum, colon, and pancreas was CYP3A4 or CYP3A3, whereas CYP3A5 was the major protein present in stomach. Both CYP3A4 and CYP3A5 mRNA were detectable in all regions of the digestive tract using the polymerase chain reaction (PCR); however, only CYP3A4 could be detected by Northern blot analysis. CYP3A7 mRNA was consistently detected only in the liver by PCR and CYP3A3 mRNA was not detected in any of the tissues. We conclude that CYP3A4 and CYP3A5 are present throughout the human digestive tract and that differences in the expression of these enzymes may account for inter-organ differences in the metabolism of CYP3A substrates.

Enzyme immunoassay using native envelope glycoprotein (gp160) for detection of human immunodeficiency virus type 1 antibodies

An enzyme immunoassay using the purified native gp160 for the detection of human immunodeficiency virus type 1 (HIV-1) antibody was developed. This assay was determined to be highly specific, since (i) 157 serum samples that were confirmed negative by Western blot (immunoblot) (WB) were negative, (ii) 41 serum samples from populations with medical conditions that might cause nonspecific assay reactivity were all negative, and (iii) all 15 serum samples that showed false-positive reactions in one or more commercial HIV-1 screening tests were negative. The assay gave 100% specificity with a randomly selected and unlinked panel of 1,000 serum samples from healthy blood donors. The sensitivity of the assay was assessed by testing 238 samples confirmed as HIV-1 antibody positive by a standardized WB assay. All 238 serum samples (100%) were reactive in the native gp160 assay. In a dilution panel of 14 weakly WB-positive serum samples, 7 samples reacted two-to fivefold more strongly in the gp160 assay than in a virus lysate-based assay; the remaining 7 samples gave comparable reactivities in the two tests. The reactivities of 13 of these 14 serum samples in the gp160 assay were higher than in a commercial enzyme immunoassay that uses a recombinant envelope protein as the antigen. The native gp160 assay was more sensitive to identify seroconversion. In a well-characterized panel of sequential blood samples from a seroconverter, the new assay detected antibodies at least one sample ahead of the other commercial assays tested.

Detection of human immunodeficiency virus type 1 p24 antigen and plasma RNA: relevance to indeterminate serologic tests

BACKGROUND

Most enzyme immunoassay-reactive specimens producing indeterminate Western blot results belong to individuals who are not infected with human immunodeficiency virus type 1 (HIV-1). However, a small percentage may correspond to early seroconversion or advanced disease, at which stage partial reactivity on Western blot may be observed.

STUDY DESIGN AND METHODS

To determine the utility of HIV-1 p24 antigen and cell-free RNA detection for the resolution of Western blot-indeterminate serologic results, several types of enzyme immunoassay-positive, sero-indeterminate specimens were analyzed. Samples were obtained from infected individuals at the time of seroconversion (n = 20), from patients with AIDS (n = 2), as specimens from clinical samples obtained for diagnostic testing (n = 57), from blood donors producing persistent indeterminate results (n = 47), and from random blood donors (n = 72).

RESULTS

HIV-1 p24 antigen was detected in 10 of 20 specimens collected from 9 of 12 individuals who seroconverted and in 2 of 2 AIDS patients. HIV-1 plasma RNA was positive in 22 of 22 samples from those 14 individuals. All of 57 diagnostic specimens and 47 samples obtained from persistently indeterminate donors were negative for HIV-1 p24 antigen and plasma HIV-1 RNA. One of 72 blood donor specimens was positive for HIV-1 plasma RNA and had borderline reactivity for p24 antigen.

CONCLUSION

The detection of plasma RNA appears to be sensitive and specific; negative test results may be used to identify false-positive serologic reactions. The detection of p24 antigen and plasma RNA can also be used to confirm HIV-1 infection in persons with indeterminate serologic results associated with early seroconversion or late-stage disease.

Human T-lymphotropic virus type II in Panamanian Guaymi Indians

BACKGROUND

Currently, human T-lymphotropic virus type II (HTLV-II) is the most prevalent human retrovirus, detected in persons presenting to donate blood in the United States. Only scant information is available with which to counsel HTLV-II-seropositive deferred donors or other persons about the ways in which they may spread HTLV-II to others.

STUDY DESIGN AND METHODS

To increase understanding of the modes of transmission of HTLV-II, a seroepidemiologic study was conducted among Panamanian Guaymi Indians, a recently identified focus of endemic HTLV-II infection. Subjects were tested for serologic evidence of infection by HTLV-II, HTLV type I, hepatitis B virus, and nine other infectious agents by enzyme immunoassays and specific confirmatory tests.

RESULTS

Nine (8.3%) of 109 persons tested HTLV-II-seropositive. HTLV-II seropositivity was more likely in persons with serologic evidence of prior hepatitis B virus infection. Sexual contact with HTLV-II-seropositive partners, but neither parenteral exposure nor breast-feeding, was identified as a risk factor for HTLV-II.

CONCLUSION

In Guaymi Indians, HTLV-II appears to be spread primarily through sexual transmission.

Identification of rifampin-inducible P450IIIA4 (CYP3A4) in human small bowel enterocytes

Enzymes within the P450IIIA (CYP3A) subfamily appear to account for significant "first pass" metabolism of some drugs in the intestine. To identify which of the known P450IIIA genes are expressed in intestine, enterocyte RNA was hybridized on Northern blots with synthetic oligonucleotides complementary to hypervariable regions of hepatic P450IIIA4, P450IIIA5, and P450IIIA7 cDNAs. Hybridization was detected only with the P450IIIA4-specific oligonucleotide. The identity of the hybridizing mRNA was confirmed to be P450IIIA4 by direct sequencing of a DNA fragment amplified from enterocyte cDNA by the polymerase chain reaction. To determine if enterocyte P450IIIA4 is inducible, biopsies of small bowel mucosa were obtained from five volunteers before and after they received 7d of treatment with rifampin, a known inducer of P450IIIA4 in liver. Rifampin treatment resulted in a five- or eightfold mean increase (P < 0.05) in the biopsy concentration of P450IIIA4 mRNA when normalized for content of sucrase isomaltase or intestinal fatty acid binding protein mRNAs, respectively. Rifampin also induced P450IIIA immunoreactive protein in enterocytes in each of the subjects, as judged by immunohistochemistry, and resulted in a 10-fold increase in P450IIIA4-specific catalytic activity (erythromycin N-demethylation) in the one patient studied. Our identification of inducible P450IIIA4 in enterocytes may in part account for drug interactions characteristic of P450IIIA4 substrates and suggests a strategy for controlling entry into the body of a major class of xenobiotics.

Characterization of a novel receptor in toad retina with dual specificity for insulin and insulin-like growth factor I

The biochemical properties of insulin receptors from toad retinal membranes were examined in an effort to gain insight into the role this receptor plays in the retina. Competition binding assays revealed that toad retinal membranes contained binding sites that displayed an equal affinity for insulin and insulin-like growth factor I (IGF-I). Affinity labeling of toad retinal membrane proteins with 125I-insulin resulted in the specific labeling of insulin receptor alpha-subunits of approximately 105 kDa. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of partially reduced (alpha beta-heterodimer) receptors affinity-labeled with 125I-insulin indicated the presence of a disulfide-linked beta-subunit of approximately 95 kDa. Endoglycosidase F digestion of the affinity-labeled alpha-subunits increased their mobility by reducing their apparent mass to approximately 83 kDa. This receptor was not detected by immunoblot analysis with a site-specific antipeptide antibody directed against residues 657-670 of the carboxy terminal of the human insulin receptor alpha-subunit, whereas this antibody did label insulin receptor alpha-subunits from pig, cow, rabbit, and chick retinas. In in vitro autophosphorylation assays insulin stimulated the tyrosine phosphorylation of toad retina insulin receptor beta-subunits. These data indicate that toad retinal insulin receptors have a heterotetrameric structure whose alpha-subunits are smaller than other previously reported neuronal insulin receptors. They further suggest that a single receptor may account for both the insulin and IGF-I binding activities associated with toad retinal membranes.

Retroviral infections transmitted by blood transfusion

Modifications in donor screening and the introduction of laboratory testing of donated blood for anti-HIV-1 and anti-HTLV-I have resulted in a significant reduction in the risks of retroviral infections from blood transfusion. Presently, the American Red Cross detects an average of eight carriers of human immunodeficiency virus, type 1 (HIV-1) per 100,000 otherwise acceptable blood donors (0.008 percent), compared with an average of 35 per 100,000 (0.035 percent) when testing for HIV-1 antibodies began in 1985. Surveillance studies in the United States indicate a small likelihood that HIV-2 carriers will pass current screening procedures and be accepted as blood donors. Even if an HIV-2-infected person were to be accepted as a blood donor, there is a 42-92 percent likelihood that this person's blood would be detected as infective for HIV-2 and excluded because of serological cross-reactions that occur in the EIA for HIV-1 antibodies. During 1989, which was the first year that donated blood was routinely tested for antibodies to human T-lymphotropic virus, type I (HTLV-I) in the United States, approximately nine in 100,000 donors (0.009 percent) were confirmed positive for antibodies to HTLV-I, and their donated blood was excluded. Subsequent testing has revealed that a significant number of these persons whose sera was reactive by the HTLV-I EIA were, in fact, infected by HTLV-II. Epidemiological studies of human retroviral infections (HIV-1, HIV-2, HTLV-I, and HTLV-II) continue to provide important data and direction for improving criteria for qualifying blood donors.

[Immunochemical identification and localization of cytochrome P-45OHS; isozyme in human gastric mucosa and gastric carcinoma]

Monoclonal antibody to rat liver cytochrome P-450 j isozyme, an activating enzyme specific to nitrosamine metabolism, was used in combination with immunoblotting, densitometer scanning of SDS-PAGE gels, and immunohistochemical staining, there was a trace of P-450 isozyme (Mr. 51. 5 kd) in human gastric mucosa with or without cancer. It was similar to P-450 j in molecular weight, catalysis and immunochemistry. We named it P-450 HSj isozyme. Both in 25 gastric cancer patients and 17 non-cancer patients, the concentrations (%) of P-450 HSj in the mucosa of the lesser curvature were higher than those of the greater curvature (P less than 0.01). This might be one of the important reasons why gastric carcinoma caused by nitrosamines is most common in the lesser curvature. The P-450 HSj was localized in the cytoplasm of some epithelial cells, especially in the glands with hyperplastic and intestinal metaplastic changes adjacent to carcinoma. It was also found in some normal glands and in tumor cells of highly differentiated adenocarcinoma, but not in tumor cells of lowly differentiated adenocarcinoma.

A test for human cytomegalovirus-specific immunoglobulins using a modification of a commercial test kit

A technique (Ig-EIA) for the detection of CMV-specific IgG, IgM and IgA in human blood is described. Ig-EIA utilizes alkaline phosphatase-labeled goat anti-human IgG, IgM and IgA as a detection probe and CMV antigen-coated solid phase from commercial kits. Ig-EIA is compared to indirect fluorescent assay (IFA) and indirect hemagglutination (IHA) for sensitivity and specificity. On sequential samples of blood from a set of patients, Ig-EIA clearly demonstrated seroconversion in CMV-specific IgG and IgM. A test of 332 blood donors by Ig-EIA showed 177 (53%) had CMV-specific IgG and 17 (5%) had CMV IgM. Only two of the 17 donors with CMV IgM were nonreactive for CMV-IgG. The potential of CMV-IgM as an indicator of CMV infectivity is discussed.

Failure of topical prostaglandin inhibitors to improve wound healing following deep partial-thickness burns

The present study was designed to determine the efficacy of topical inhibitors of prostaglandins on wound healing. Two uniform deep partial-thickness burns were inflicted on mirror-image areas of guinea pig backs by an aluminum template heated to 75 degrees C and applied for 10 seconds. Indomethacin was tested extensively in a wide range of concentrations in groups of six or more animals each. The healing rates measured at 21 days postburn showed that topical indomethacin at each concentration tested was not effective for improving wound healing. In fact, the treated sites were consistently worse than the control sites. Moreover, the drug adversely affected the healing process proportional to the concentration and was associated with death, which was related to perforations of the GI tract. Also, the India ink filling in the dermal microcirculation was no better in the experimental wounds than in the controls. The evaluations for hair growth were definitely in favor of the controls. The other tested inhibitors, ibuprofen, flurbiprofen, tolmetin, zomepirac, piroxicam, and dipyridamole, also failed to show any benefit.

Morphogenesis of vaccinia virus in the process of envelopment as observed by freeze-etching electron microscopy

The morphogenesis of vaccinia virus was studied during its synthesis in HeLa cells. Freeze-etching electron microscopy demonstrated intramembrane granules attached to convex faces, a granule-free area characterized by eccentric location and smooth appearance, and an eccentric nucleoid structure occasionally associated with a membranous structure. It is postulated that the granule-free area may be a precursor of the nucleoid envelope.

Preliminary study on the age of Yuanmou man by palaeomagnetic technique

Since the discovery of the fossil teeth of Yuanmou man (Homo erectus yuanmouensis) on May 1, 1965 from Yuanmou county, Yunnan Province, the Institute of Geomechanics, relying on the local poor and lower-middle peasants and co-operating with other units concerned, has been conducting intensive researches on the fossil man-bearing strata as well as Quaternary glaciation. Palaeomagnetic technique lately used in the study has for the first time shown that the Yuanmou man appeared around 1.7 million years ago, earlier than both Peking man and Lantien man. Hence the age formerly assigned to the earliest fossil man in China has to be increased by more than a million years. Furthermore, as the age of Yuanmou formation is fixed at 1.5--3.1 million years, the length of Quaternary has to be extended by more than two million years. Of special interest is that under the Yuanmou formation there occur glacial traces which prove beyond doubt the existence of glaciation over 3 million years ago. This is a new discovery in the Quaternary history of China, and provides a new approach to the future study of this period.