Heat shock effects on phosphorylation of protein synthesis initiation factor proteins eIF-4E and eIF-2 alpha in Drosophila

Heat shock of mammalian cells causes changes in initiation factor phosphorylation that likely contribute to or cause the translation reprogramming characteristic of heat shock. In these investigations we have carried out a parallel analysis of Drosophila, focusing on eIF-4E and eIF-2 alpha. eIF-4E plus associated proteins was purified from lysates by m7GTP-Sepharose chromatography. A minor fraction (< 10%) of eIF-4E is phosphorylated under normal growth conditions, and phosphorylation decreases during heat shock. Drosophila eIF-2 alpha has been identified by in vitro translation of T7 RNA polymerase-transcribed mRNA, and immunoblotting with anti-Drosophila eIF-2 alpha antiserum. 32P-labeling analysis (unfractionated cell lysates and immunoprecipitates) detects phosphorylated eIF-2 alpha, whose amount increases approximately 2-3-fold upon heat shock. Immunoblotting analysis of two-dimensional gel-resolved proteins to determine the mass fraction of eIF-2 alpha phosphorylated detects a single eIF-2 alpha spot in both normal temperature and heat shocked cells, indicating less than 5% phosphorylation after and before heat shock. Staining quantification is consistent with this low prevalence. A major phosphoprotein which copurifies with eIF-4E on m7GTP-Sepharose shows decreased overall phosphorylation and decreased association with eIF-4E following heat shock. Several distinctive characteristics of this phosphoprotein suggest it is Drosophila eIF-4B.

Injecting drug use and HIV infection in southwest China

OBJECTIVES

To determine the prevalence of drug injection among drug users, the seroprevalence of HIV and risk factors for HIV infection among injecting drug users (IDU), and to determine heterosexual transmission of HIV among IDU and their spouses in southwest China.

METHODS

Using a cross-sectional design, we conducted an HIV seroprevalence and behavioral survey in three rural counties of Yunnan province, Ruili, Longchuan and Luxi in southwest China, bordering Myanmar (Burma). A total of 860 drug users were recruited in randomly selected communities at the three study sites (response rate, 97%). In addition, a random sample of 62 wives of HIV-infected IDU were assembled from 460 known HIV-positive IDU in Ruili and Longchuan (response rate, 81%).

RESULTS

In the sample of 860 drug users, 33% reported injecting drugs. Among the 282 subjects who injected drugs, 82% began intravenous drug use after 1988; 64% injected drugs at least once every day. All subjects shared needles but none cleaned the injection equipment with alcohol or bleach. Overall, 49% tested HIV-positive. HIV seropositivity was independently correlated with a longer history of drug injecting, daily injecting, frequent needle-sharing, being younger, and living in Ruili county. Among the 62 wives of HIV-positive IDU, none used condoms during sex and 10% tested HIV-positive.

CONCLUSIONS

We conclude that the introduction of HIV into drug-using communities and the rapid increase in heroin injecting in this population appear to have triggered an explosive HIV epidemic among IDU in southwest China. We recommend that AIDS prevention efforts should begin immediately and focus on discouraging the shift from opium smoking to heroin injecting, needle-sharing, and unprotected sex among drug users and their partners.

Isolation and characterization of the Drosophila melanogaster eIF-2 alpha gene encoding the alpha subunit of translation initiation factor eIF-2

Genomic and cDNA clones encoding the Drosophila melanogaster alpha-subunit of translational initiation factor 2 (eIF-2 alpha) were isolated. The D. melanogaster eIF-2 alpha gene encodes a 341 amino-acid (aa) protein that shares 57 and 44% identity to its human and yeast homologues, respectively. The regulatory phosphorylation site at Ser50 is embedded in a segment of 19 conserved aa residues. Analysis of the genomic DNA and cDNA clones indicated that eIF-2 alpha is a single-copy gene and its coding region is interrupted by a 260-bp intron. The D. melanogaster eIF-2 alpha mRNA is 1350 nt in length and is expressed throughout development.

[Cohort study of HIV infection among drug users in Ruili and other counties in Yunnan Province, China]

In 1993, a second survey was conducted in Ruili City and other two counties, where a cohort study field was established last year. Seven hundred and fifty five drug users and one hundred and two spouses of HIV infected IDUs were interviewed. Nine samples among 54 from 89 IDUs in cohort were tested as seroconversion. The seroconversion rate (incidence rate) in IDUs (per hundred person years) in Ruili, Longchuan, and Luxi as well were 40.0, 12.2 and 0, respectively in 1993, comparing to 43.2, 12.2 and 0 in 1992. Thirty eight were tested as positive among 108 samples from 116 newly recruited IDUs. The seroprevalence rates in this three counties were 85.7%, 40.0% and 0 in 1993, comparing to 81.8%, 44.6% and 5.1% in 1992. A coordination of the level between seroconversion and seroprevalence was observed. A increasing trend of seroprevalence among the spouses of HIV positive IDUs was found, the seroprevalence rate were 3.1% in 1990, 9.8% in 1992 and 7.4% in 1993. More attention should be paid to Luxi where the ratio of intravenous drug using increased rapidly, although fewer positives and later starting of drug using was found in this county.

Use of fluorescent substrate 4-MUP in the detection of biotin-labeled DNA probes

To improve the sensitivity of detecting biotin-labeled DNA Probes, a new fluorescent substrate of alkaline phosphatase, 4-methylum belliferylphosphate (4-mup) was studied instead of conventional BCIP-NBT. The result of dot-blot hybridization demonstrates that this new substrate can be used for the colorimetric detection of biotin-labeled probes after hybridization to immobilized nucleic acids. The sensitivity is about one order of magnitude higher than that of BCIP-NBT system, and the time required for color development is very short, only about five min. It is suggested that the Bio-SA-Bio-AP-4-MUP colorimetric detection system can be widely used in gene diagnosis.

[Study on hydrolytic kinetics of metronidazole-phosphate in rabbit plasma by HPLC]

A HPLC method for the simultaneous determination of metronidazole and metronidazole-phosphate in rabbit plasma has been established. This method is simple, sensitive, reproducible and has a good linearity. It has been used to study the hydrolytic kinetics of metronidazole-phosphate in rabbit plasma. The results show that hydrolytic process of metronidazole-phosphate in vitro at 37 degrees C follows a first order kinetics with the rate constant 0.016 min-1 and half-life 43 min.

The Drosophila melanogaster stranded at second (sas) gene encodes a putative epidermal cell surface receptor required for larval development

Several lethal mutations were identified previously in the 84BD interval of the Drosophila melanogaster third chromosome (Lewis et al., 1980; Cavener et al., 1986b). We have examined the l(3)84Cd complementation group and found that mutants exhibit novel cuticular defects and die during larval development. The lethal phase occurs during the first larval molt or subsequently during the second instar larval stage; hence, we have named the gene stranded at second (sas). There are no apparent effects on the rate of development of embryos or first instar larvae. Second instar larvae which survive the molt exhibit a marked reduction in growth and eventually die as small second instar larvae. Incomplete penetrance in some weak sas alleles can yield fertile adults. In addition to the lethal phenotype, a segmentally repeated pattern of tanned spots is found within the ventral setal belts of mutant larvae. The position of the spots is always either between the fourth and fifth row of setae (cuticular projections) or between the first and second row of setae. The spots are adjacent to the muscle attachment sites in the setal belt region. Another common larval phenotype is the abnormal tanning of the ventral surface of the pharynx. The sas gene was cloned, and both the cuticular tanning and the larval lethal phenotypes were complemented by P-element-mediated transformation with a genomic DNA-cDNA construct. Three major sas transcripts are expressed throughout development in cuticle secreting epidermal tissues. The sas transcripts show stage- and tissue-specific patterns of expression with switches in transcript patterns occurring at the molts. The inferred 1348-amino-acid sequence suggests that sas encodes a cell surface protein which functions as a receptor. The putative extracellular region contains four tandem repeats of a cysteine-rich motif which is similar to a cysteine pattern present in procollagen and in thrombospondin. Following this region are at least three copies of a fibronectin type III class repeat. The short (35 amino acids) intracellular domain contains a sequence (NPXY) that has been implicated in endocytosis via coated pits.

A comparison of metronidazole distribution following intravenous metronidazole and metronidazole phosphate disodium in mice

The distribution of metronidazole following intravenous metronidazole (MTZ) and metronidazole phosphate disodium (MNP) in mice was investigated by HPLC. The results showed no significant differences in the metronidazole concentrations of liver, kidney, heart, spleen, fat, brain, lung, stomach, jejunum, skeletal muscle, ovary, testis and epididymis (P greater than 0.05). It can be concluded that using MNP as a water-soluble substitute for MTZ should not influence the distribution of metronidazole in mice.

[A survey of blood pressure level in Uygur and Han preschool children]

A survey of blood pressure including its distribution, values of normal upper limits, and the percentages of high normal pressure of 1,113 children from 3-6 years of Uygur and Han nationalities in Wulumuqi was carried out. The mean values of systolic pressure and diastolic pressure, and the percentages of high normal pressure were lower in Uygur than in Han children, but only the difference of systolic pressure values was statistically significant.

[Pharmacological studies on the volatile oil isolated from the leaves of Pinus pumila (Pall.) Regel]

The sedative, analgesic, antipyretic and anti-inflammatory activities of the volatile oil isolated from the leaves of Pinus pumila are reported, the volatile oil being administered ip or po. The ip LD50 in mice was 0.577 +/- 0.056 ml/kg.

[Observation of efficacy of different dialytic therapies in renal transplantation preparation]

Fifty-seven cadaveric renal transplantations in fifty-five cases were analysed of them, thirty cases were prepared by continuous ambulatory peritoneal dialysis (CAPD group); twenty-seven transplantations in twenty-five cases were prepared by hemodialysis (HD group). Our data show that there is no significant difference in the survival duration between CAPD group and HD group; that there is also no significant difference in the survival duration between the two groups treated with the same immunosuppressive drugs, and that patients prepared by CAPD have a low risk of peritonitis after transplantation. It is better not to remove the Tenckhoff catheter until the graft function is stable so that it can be used for the transient peritoneal dialysis in the case of the insult of graft function or for the sampling of the peritoneal effusion for diagnosis of suspectable peritonitis after renal transplantation.