Comparison of the transportation network for public transit and private vehicles in Shanghai: An accessibility approach

This study examines the differences in service level and coverage of public transit (PT) and private vehicles (PV) with multi-source data in Shanghai. To construct computable networks and address visual results, the constrained shortest path algorithm and a spatial grid accessibility model are employed to seek the optimal path for travelers to city key points. Travel time ratio of PV and PT is applied to reflect the competitiveness of the two modes over different areas of Shanghai. Results show that for PV, although the average travel time meets the needs of car travel, 51 % of the population cannot get to graded city centers within 45 min. In addition, the PV accessibility gradually weakens from the central city to the outside, highways and expressways may be feasible solutions. For PT, half of the population can't reach any city key points within two transfers, and almost all of these people live in the suburbs. Less than 30 % of the population can reach the city key points within 1 h, of which rail transit contributes more than conventional buses. Furthermore, the travel accessibility of PV is much better than that of PT. The average travel time ratio in all comparable grids is 2.04 for hubs, and 2.10 for graded city centers. For travels to graded city centers, the travel time ratio of suburbs is 35 % higher than that of central city, indicating that the inequity distribution of public transportation resources is worse in the suburbs than in the central city. This study also measures equity performance of groups based on spatial location and income level, and we find out that more core locations and higher income lead to higher accessibility. The gap among groups is significant, with a Gini coefficient over 0.5.

[A family with developmental glaucoma and microcornea due to novel ADAMTS18 gene mutations]

This case report presents a family with developmental glaucoma accompanied by microcornea resulting from novel mutations in the ADAMTS18 gene. The index case involves a 5-year-old twin brother, who, during a routine examination, exhibited elevated intraocular pressure persisting for over a month. The peak intraocular pressure reached approximately 25 mmHg (1 mmHg=0.133 kPa) in both eyes, with a corneal diameter of less than 10 mm. Ocular examination revealed an enlarged cup-to-disc ratio, and optical coherence tomography (OCT) demonstrated thinning of the retinal nerve fiber layer and ganglion cell layer. Ultrasound biomicroscopy combined with gonioscopy indicated partial angle closure and abnormal anterior chamber angle development. The ocular manifestations in the twin brother were consistent with those observed in the twin sister. The clinical diagnosis was bilateral developmental glaucoma with microcornea. Genetic sequencing identified two novel compound heterozygous mutations in the ADAMTS18 gene in the twins: Mutation 1 (M1) involving the variant site 1 (c.3436C>T:p.R1146W) and Mutation 2 (M2) involving the variant site 2 (c.1454T>G:p.F485C). Ocular examinations of four additional family members were normal. Genetic testing revealed that the twins' father and sister carried M1, while the index case's mother and brother carried M2. This report underscores a unique association between ADAMTS18 gene mutations and developmental glaucoma with microcornea within a familial context, emphasizing the importance of genetic screening for early diagnosis and targeted management strategies.

Cold Spray: Over 30 Years of Development Toward a Hot Future

Cold Spray (CS) is a deposition process, part of the thermal spray family. In this method, powder particles are accelerated at supersonic speed within a nozzle; impacts against a substrate material triggers a complex process, ultimately leading to consolidation and bonding. CS, in its modern form, has been around for approximately 30 years and has undergone through exciting and unprecedented developmental steps. In this article, we have summarized the key inventions and sub-inventions which pioneered the innovation aspect to the process that is known today, and the key breakthroughs related to the processing of materials CS is currently mastering. CS has not followed a liner path since its invention, but an evolution more similar to a hype cycle: high initial growth of expectations, followed by a decrease in interest and a renewed thrust pushed by a number of demonstrated industrial applications. The process interest is expected to continue (gently) to grow, alongside with further development of equipment and feedstock materials specific for CS processing. A number of current applications have been identified the areas that the process is likely to be the most disruptive in the medium-long term future have been laid down.

[A cross-sectional study on metabolic syndrome and its abnormal components in cancer patients]

From December 2017 to December 2018, 3 509 subjects who had regular physical examination in Health Management Center, Tianjin Medical University General Hospital were enrolled in our study, including 399 cancer patients, 1 555 chronic disease patients, and 1 555 healthy control, respectively. The mean age was (55.87±11.98) years, and 31.38% were men. The prevalence of MS among chronic disease group (42.44%) was higher than that of cancer group (34.59%) and healthy control group (18.65%) (P<0.001). Compared with healthy control group, the OR (95%CI) values of MS risk in cancer group and chronic disease group were 2.13 (1.61-2.83) and 2.85 (2.23-3.66), respectively; the OR (95%CI) values of MS risk were 3.56 (2.04-6.21) and 2.77 (1.46-5.25) in breast cancer and thyroid cancer, respectively.

[Emerging of Japanese encephalitis virus and Getah virus from specimen of mosquitoes in Inner Mongolia Autonomous Region]

Objective: To investigate the types and distribution of blood-sucking insects and arboviruses in Inner Mongolia autonomous region, and provide basic data for the prevention of arbovirus transmitted disease. Methods: Blood-sucking insects were collected by lamp trapping method in nature. Mosquito samples were classified according to morphologic characteristics and then stored at liquid nitrogen. Viruses were isolated in cell culture and characterized, using molecular biological methods. Results: A total of 24 240 mosquitoes and 17 110 aphids were collected from 2 sites of 5 counties (Flags) in Inner Mongolia in 2014 and during 2017-2018. Among them, Japanese encephalitis virus gene was detected in Culex pipiens pallens, and 4 virus strains isolates which could be stably passaged. The isolates were identified as Getah virus and densonucleosis virus by molecular biology identification. Phylogenetic analysis on the E2 gene of the Getah virus (NMDK1813-1) showed that it belonged to the same evolutionary branch of the Gansu isolates (GS10-2) and having six common amino acid variation sites. Conclusions: The emergence of Japanese encephalitis virus and Getah virus from specimen of mosquitoes in Inner Mongolia indicated the new challenges on the prevention and control of arbovirus and related diseases. The results pf this study provided basic data for the prevention and control stretagies of arbovirus transmitted diseases in Inner Mongolia.

[Lamina cribrosa defect and progress of glaucoma]

Lamina cribrosa (LC) is considered as the original site of glaucomatous damage of axons of retinal ganglion cells, and therefore understanding the morphological changes in the LC will help to uncover the pathogenesis of glaucoma. Previous studies have indicated that the progress of glaucomatous optic neuropathy may be associated with the LC defects. Based on imaging by swept source optical coherence tomography B-Scan of the optic discs of patients with glaucoma, for the first time the spontaneous local LC defects have been found to balance the gradient between intraocular and cerebrospinal fluid pressures, which in turn can slow down the progress of glaucomatous optic neuropathy. This article provides the direct evidence supporting the role of intraocular and cerebrospinal fluid pressure gradient in the pathogenesis of glaucoma. This finding will increase our understanding of the mechanisms underlying glaucoma and help to develop novel strategies for its treatment and prognosis analysis. (Chin J Ophthalmol, 2020, 56: 17-20).

The diagnostic accuracy of CT-guided percutaneous core needle biopsy and fine needle aspiration in pulmonary lesions: a meta-analysis

AIM

To determine and compare the diagnostic value of computed tomography (CT)-guided percutaneous core needle biopsy (PCNB) and percutaneous fine-needle aspiration biopsy (PNAB) in pulmonary lesions.

MATERIALS AND METHODS

PubMed, EMBASE, and the Web of Science were systematically searched for relevant studies that investigated the diagnostic accuracy of CT-guided PCNB and/or PNAB for pulmonary lesions up to December 2014. After study selection, data extraction, and quality assessment, the sensitivity (SEN), specificity (SPE), diagnostic odds rate (DOR), positive likelihood ratios (PLR), negative likelihood ratios (NLR), and summary receiver operating characteristic (SROC) curves were calculated using the Meta-Disc 1.4 software.

RESULTS

Nineteen publications, including 21 independent studies, met the inclusion criteria. Of them, 15 studies were included in the PCNB group and six studies in the PNAB group. The pooled SEN, SPE, DOR, PLR, NLR, and SROC were 0.95, 0.99, 54.72, 0.06, 821.90, and 0.98 in the PCNB group and 0.90, 0.99, 24.71, 0.14, 210.72, and 0.98 in the PNAB group, respectively.

CONCLUSION

Based on current evidence, both PCNB and PNAB can be used as diagnostic methods to distinguish benign and malignant pulmonary lesions; the difference between PCNB and PNAB regarding diagnostic accuracy of benign or malignant pulmonary lesions is not obvious.

A novel FBN1 heterozygous mutation identified in a Chinese family with autosomal dominant Marfan syndrome

The purpose of this study was to identify the clinical features and mutations in the fibrillin-1 gene (FBN1) in a large Chinese family with autosomal dominant Marfan syndrome (MFS). Seventeen members from a Chinese family of 4 generations were included in the study. All members underwent complete ophthalmic examination. Molecular genetic analysis was performed on all subjects. All exons of FBN1 were amplified by polymerase chain reaction, sequenced, and the sequences were compared with a reference database. Variations were evaluated in family members as well as 100 normal controls. Changes in structure and function of the protein induced by amino acid variation were predicted by bioinformatic analysis. Ectopia lentis, dolichostenomelia, arachnodactyly, and tall stature were present in all patients diagnosed with MFS. The novel heterozygous missense mutation c.2243 T>G (p.C781W) in exon 19 of FBN1 was identified in all 5 patients, but not in other family members or 100 normal controls. This mutation caused an amino acid substitution of cysteine to tryptophan at position 781 (p.C781W) of the FBN1 protein. This mutation occurred in a highly conserved region and may cause structural and functional changes in the protein according to our bioinformatic analysis. Our results suggest that the novel mutation C781W of FBN1 is responsible for the pathogenesis of MFS in this pedigree.

A novel mutation of PAX6 identified in a Chinese twin family with congenital aniridia complicated with nystagmus

Genetic variations within the paired box gene 6 (PAX6) gene are associated with congenital aniridia. To detect the genetic defects in a Chinese twin family with congenital aniridia and nystagmus, exons of PAX6 were amplified by polymerase chain reaction (PCR), sequenced and compared with a reference database. Six members from the family of three generations were included in the study. The twins' father presented with congenital aniridia, nystagmus and cataract at birth, while the twins presented with congenital aniridia and nystagmus. A novel mutation c.888 insA in exon 10 of PAX6 was identified in all affected individuals. This study suggests that the novel mutation c.888 insA is likely responsible for the pathogenesis of the congenital aniridia and nystagmus in this pedigree. To the best of our knowledge, this is the first report of this mutation in PAX6 gene in pedigree with aniridia. Furthermore, no PAX6 gene defect was reported in twins with congenital aniridia.

A novel NF1 frame-shift mutation (c.702_703delGT) in a Chinese family with neurofibromatosis type 1

This study aimed to characterize the clinical features of a Chinese pedigree with neurofibromatosis type 1 (NF1) and to identify mutations in the NF1 gene. In this three-generation family containing 8 members, 5 had been diagnosed with NF1 and the others were asymptomatic. All members of the family underwent complete medical examinations. Molecular genetic analyses were performed on all subjects included in the study. All exons of NF1 were amplified by polymerase chain reaction, sequenced, and compared with a reference database. Possible changes in function of the protein induced by amino acid variants were predicted by bioinformatic analysis. In this family, the 5 patients presented different clinical phenotypes, but all manifested typical café-au-lait macules. One novel frame-shift mutation, c.702_703delGT, in exon 7 of NF1 was identified in all affected family members, but not in the unaffected family members or in 102 normal controls. This mutation generates a premature stop codon at amino acid position 720. Additionally, a synonymous mutation c.702 G>A was found in 3 family members, including 2 affected and 1 normal individuals. In conclusion, our study suggests that a novel c.702_703delGT frame-shift mutation in NF1 is likely to be responsible for the pathogenesis of NF1 in this family. To the best of our knowledge, it is the first time that a c.702_703delGT mutation has been identified in a family with neurofibromatosis type 1.

Phase IIb trial of fluorouracil, leucovorin, oxaliplatin, and paclitaxel (POF) compared with fluorouracil, feucovorin, and irinotecan (IF) as first-line treatment for advanced gastric cancer (AGC)

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Background: Primary results of POF as 1st and 2nd line treatment for AGC have been presented at ASCO 2007 and 2008. We report here data on the feasibility and the toxicity of POF versus IF(Dank, et al, ASCO 2005) in 1st line treatment of AGC. Methods: Patients with previously untreated, advanced, unresectable, and histologically confirmed adenocarcinoma of the gastric or gastroesophageal junction were randomly assigned to POF or IF regiment. Treatment was continued until disease progressed, unacceptable toxicity, or patient choice. Results: 25 patients were entered in this study between March 2007 and July 2007: 13 in the POF group and 12 in the IF group. The median patient age was 55 years (range, 36 to 67 years), 18 were males and 7 were females. No complete response was observed. The response rate was 62.5% (POF) and 33.3% (IF) respectively. At a median follow-up of 285 days, 7(POF) versus 6(IF) patients were still alive. Hematological toxicity was the most frequent toxicity in both groups. Grade 3 to 4 neutropenia were 38.5% (POF) versus 8.3% (IF). Diarrhea was found 0% and 8.3% in POF and IF group respectively. No grade 3 peripheral neurotoxicity was observed. Conclusions: Compared with IF regiment, POF could also be used as first-line treatment for AGC with acceptable safety profile, good efficacy, and more encouraging results.

No significant financial relationships to disclose.

Results of semimonthly 5-florouracil/leucovorin combined with paclitaxel and oxaliplatin in treatment of advanced gastric cancer (AGC)

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Background: At present there is still no standard chemotherapy regimen for AGC, the progress of AGC exhibits a pessimistic result with a median survival of less than 9 months. The purpose of this trial was designed to enhance the treatment efficacy for AGC by using semimonthly FU/LV combined with paclitaxel and oxaliplatin. Methods: Patients chosen with histologically proven diagnosis of adenocarcinoma of the stomach or gastroesophageal junction, locally advanced (i.e., unresectable) or metastatic and measurable disease. The chemotherapy regimen was comprised of a 3-hour infusion of 135 mg/m2 of paclitaxel followed by oxaliplatin 85 mg/m2 and LV 400 mg/m2, administered simultaneously as a 2-hour infusion, then continued a 46-hour infusion of FU 2.4 g/m2 using an ambulatory pump. Treatment was continued until disease progressed, unacceptable toxicity, or patient choice. The primary endpoint was response rate. Results: Twenty-seven patients were enrolled onto this study in our center between September 19, 2005 and December 25, 2006. The median patient age was 51 years (range, 28 to 66 years), 21 were males and 6 were females. All patients received the chemotherapy between at least two cycles and maximum eight cycles with a median of three. Four CRs of 27 enrolled patients, fifteen PRs and eight SDs were observed. Nineteen patients were chemonaive within enrolled patients: Four CRs, eleven PRs. At a median follow-up of 8.7 months, the median survival was 6.8 months. Frequent grade 3 to 4 toxicities were: neutropenia (37.0%), stomatitis (7.4%), nausea (7.4%), vomiting (7.4%), hepatic dysfunction (3.7%), paresthesia (18.5%). No treatment-related death occurred. Conclusion: Semimonthly FU/LV combined with paclitaxel and oxaliplatin appears to be of well efficacy and is well tolerated in patients with AGC. Currently, this regimen is being tested in the phase III trial involving patients with AGC on the basis of well result.

No significant financial relationships to disclose.

Treatment of childhood phimosis with a moderately potent topical steroid

BACKGROUND

Recently, topical steroid application has been shown by a small number of studies to be an effective alternative to circumcision for the treatment of phimosis. However, only potent or very potent corticosteroids have been more thoroughly studied in this treatment option. A prospective study was conducted to determine whether comparable results could be achieved using a weaker steroid cream.

METHODS

Boys, 3-13 years of age, with non-retractable foreskin due to a tight ring at the tip were offered the regimen of twice-daily preputial retraction and topical application of 0.02% triamcinolone acetonide cream. The degree of preputial retractability was assessed at presentation and at 4 and 6 weeks of treatment. Success was defined as full retraction or free retraction up to agglutination of the foreskin to the glans.

RESULTS

Eighty-three boys completed the treatment. Successful retraction was achieved in 48/83 (58%) patients after 4 weeks and 70/83 (84%) patients after 6 weeks of application. The overall response rate aggregated from six published series using 0.05% betamethasone was 87% at 4 weeks and 90% on completion of treatment. Thus, the results appear inferior when analysed at 4 weeks but compare favourably with those reported for a more potent steroid on completion of the full course of treatment.

CONCLUSIONS

Even though the triamcinolone cream used in the present study is less potent than the more commonly used 0.05% betamethasone valerate cream, it could effect comparable improvements in foreskin retractability after 6 weeks of treatment.

Relationship between thermal parameters and tumor response in hyperthermia combined with radiation therapy

BACKGROUND

In hyperthermia for cancer therapy, thermal parameters related to tumor response have not yet been clarified. We investigated thermal parameters that could predict tumor response to hyperthermia combined with radiotherapy in locally advanced malignancies.

METHODS

Fifty-four patients with locally advanced malignancies who were treated by hyperthermia in combination with radiation therapy were enrolled in this study. Local hyperthermia was induced by ultrasound heating equipment for 60 min, within 30 min after irradiation, twice a week, for a total of six to ten sessions. Radiation therapy was administered with a conventional fractionation regimen, at a total dose of 40-70 Gy. Multi-point thermometry results were obtained with every 10-s temperature data acquisition. An average of seven interstitial sites per tumor was monitored for each treatment. Univariate logistic regression analysis was used to investigate the relationship between tumor response and minimum, maximum, and average intratumor temperature (Tmin, Tmax, Tav); the cumulative minutes of treatment at temperatures exceeded by 90%, 50%, and 10% of the measured intratumoral temperatures (T90, T50, T10); and cumulative minutes of the temperature that achieved above the index temperature value in the tumor center ((Cum min T(center) > T(index)).

RESULTS

Complete and partial response rates were 32.6% and 46.2%, respectively. Univariate logistic regression analysis revealed that the temperature parameters with predictive probability were highest for Cum min T(center) > 42.5 degrees C, followed by > 42 degrees C and > 41 degrees C; and T90. Cum min T(center) > 42.5 degrees C was most significantly associated with complete tumor response (P < 0.001).

CONCLUSION

These results strongly suggest that hyperthermia is a useful adjunct to radiotherapy for increasing the local control of advanced malignancies, and that Cum min T(center) > 42.5 degrees C could be an important thermal parameter for predicting tumor response.

[A study on the risk factors of none-insulin-dependent type diabetes mellitus]

A 1:1 matched case-control study was conducted to investigate the risk factors for NIDDM in 1995. A total of 100 pairs of case and controls matched on sex, age and hopital of admission. Bivariate analysis revealed 7 factors significantly associated with NIDDM. Conditional logistic regression analysis showed that 3 of the 7 fectors: obesity, greasy and family history of diabetes were risk factors for NIDDM. That might play important roles in the etiology of NIDDM.

[Treatment of arteriovenous malformation by linear accelerator radiosurgery]

OBJECTIVE

To summarize the effectiveness of radiosurgery for cerebral arteriovenous malformations (AVMs).

METHOD

We treated with linear accelerator radiosurgery 17 patients harboring AVMs in the brain. 15 AVMs were located supratentorially and others infratentorially. All the patients were treated with single fraction. The doses at AVM margin were 15 to 30 Gy.

RESULT

AVMs disappeared in 13 of the 17 patients, reduced in 3 and unchanged in only 1 at 2 year follow up. Vasogenic edema observed in 2 patients, their neurologic deficits were all improved with steroid.

CONCLUSION

Linear accelerator radiosurgery is effective in dealing with cerebral AVMs. It provides with a new means of treatment for AVMs which can't be effectively treated with microsurgery and embolization.

Cloning of the amino-terminal and 5'-flanking region of the human MUC5AC mucin gene and transcriptional up-regulation by bacterial exoproducts

To obtain gene regulatory sequence for the mucin gene MUC5AC, we have isolated the MUC5AC amino terminus cDNA and 5'-flanking region. This was possible through the use of rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR) in which the 5' sequence of the human gastric mucin cDNA HGM-1 (1) was used to design the first MUC5AC-specific primer. Primers for subsequent rounds of RACE were designed from the 5'-ends of amplified RACE products. After five rounds of RACE-PCR, we could no longer generate upstream extensions of the cDNA and hypothesized that we had reached the 5'-end. Primer extension and RNase protection analysis confirmed this. Combined nucleotide sequence for the RACE-PCR products was 3.3 kb with an open reading frame encoding 1100 amino acids. A putative translation start site was found at nucleotide +48. This was followed by a 45 nucleotide putative signal sequence. This amino-terminal sequence contains no tandem repeats but is >60% similar to the amino-terminal nucleotide sequence of MUC2. The positions of cysteine residues in this MUC2-similar region are almost 100% conserved between the two genes. Northern analysis showed expression of cognate RNA in the stomach and airway but not muscle and esophagus. This pattern was the same as that obtained using previously reported 3'-MUC5AC sequences. We have cloned approximately 4 kb of genomic DNA upstream of the transcription start site and have sequenced 1366 nucleotides containing a TATA box, a CACCC box, and putative binding sites for NFkappaB and Sp 1. Within 4 kb of the transcription start site are elements mediating transcriptional up-regulation in response to bacterial exoproducts.

A rapid and quantitative assay for inhibition of 3' cleavage activity of HIV-1 integrase

The human immunodeficiency virus-1 (HIV-1) integrase catalyzes the specific removal of two nucleotides at either 3' end of each long terminal repeat (LTR) sequence of the proviral DNA duplex. The most commonly used in vitro assays for integrase employ 5' end 32P-labeled double-stranded oligonucleotides and the product of integrase-associated endonuclease activity is visualized by denaturing gel electrophoresis followed by autoradiography. We report here a simple assay system based upon the liberation of [35S]GT dinucleotide from the 3' end of a double-stranded U5 LTR sequence derived from HIV-1. The uncleaved labeled substrate and the unlabeled large product are removed by adsorption to polyethyleneimine cellulose followed by centrifugation. The small labeled GT dinucleotide product released in the supernatant is quantitated in terms of counts released as a function of time. Since the method is rapid and quantitative, it should be useful in the kinetic evaluation of inhibitors of the 3' cleavage activity of HIV-1 integrase.

A drug resistance mutation in the inhibitor binding pocket of human immunodeficiency virus type 1 reverse transcriptase impairs DNA synthesis and RNA degradation

Selection of the IIIB strain of human immunodeficiency virus type (HIV-1) resistant to the (alkylamino)piperidine-bis(heteroaryl)piperazine (AAP-BHAP) U-104489 results in substitution of a glycine to glutamate at residue 190 (G190E) of reverse transcriptase (RT). The AAP-BHAP resistant HIV-1 displays reduced in vitro replication capacity [Olmsted, R. A., et. al. (1966) J. Virol. 70, 3698-3705]. We report here that the G190E mutation in recombinant heterodimeric HIV-1 RT, compared to the wild-type RT (G190) or a G190A control mutant, results in a 40% and 80% reduction in the polymerase and RNase H specific enzymatic activities, respectively. A primer-extension assay that allowed determination of DNA elongation by the G190E mutant RT on a heteropolymeric HIV-1 gag-based RNA template showed an overall decrease in DNA polymerization. The size distribution of products generated by G190E RT-associated RNase H digestion of RNA from [35S]poly(rA).poly(dT) was markedly distinct from that of the G190A RT and was consistent with the observed reduction in RT-associated RNase H activity of the G190E RT. When challenged with unlabeled substrates, the G190E RT was relatively nonprocessive with respect to DNA synthesis and RNA degradation. It is concluded that the deleterious effect of the G190E resistance mutation on both of these RT functions is most likely involved in the observed retarded replication capacity of the AAP-BHAP-(U-104489-) resistant HIV-1.

Characterization of the p68/p58 heterodimer of human immunodeficiency virus type 2 reverse transcriptase

Recently we demonstrated that the p58 subunit of p68/p58 HIV-2 reverse transcriptase (RT) heterodimer, produced by processing of p68/p68 homodimer with recombinant HIV-2 protease, terminates at Met484 [Fan, N., et al. (1995) J. Biol. Chem. 270, 13573-13579]. Here we describe purification and characterization of the p68/p58 heterodimer of recombinant HIV-2 RT. It exhibited both RT and RNase H activities, obeyed Michaelis-Menten kinetics, and was competitively inhibited by the DNA chain terminator ddTTP (Ki[app] = 305 +/- 20 nM). The HIV-2 RT-associated RNase H exhibited a marked preference for RNA hydrolysis from a HIV-1 gag-based heteropolymeric RNA/DNA hybrid in the presence of either Mg2+ or Mn2+, compared to the [3H]poly(rA).poly(dT) or [3H]poly(rG).poly(dC) homopolymeric substrates. Relative to HIV-1 RT, the RNase H activity of HIV-2 RT was only 5% toward the [3H]poly(rA).poly(dT) in the presence of Mg2+. The size distribution of products generated from [3H]poly(rA).poly(dT) by HIV-2 RT-associated RNase H was markedly distinct from that of HIV-1 RT in the presence of Mg2+ or Mn2+. The p68/p58 HIV-2 RT heterodimer, produced by specific cleavage using HIV-2 protease, should be useful for inhibition and biophysical studies aimed at discovering and designing drugs directed toward HIV-2.

Regional localization of the putative cell surface receptor for HTLV-I to human chromosome 17q23.2-17q25.3

The gene for the cell surface receptor for HTLV-I, the etiologic agent of adult T-cell leukemia and HTLV-I-associated myelopathy, has been localized to distal human chromosome 17q. A panel of somatic cell hybrids containing fragments of human 17q as the only human genetic component was mapped with a set of 10 chromosome 17 probes and utilized to regionally localize the gene. When compared to the murine fibroblast fusion partner, L-M(TK-), and a hybrid cell line containing human chromosome 20, human 17q-containing hybrid cells bound high levels of both HTLV-I virions and the monoclonal antibody, Mab 34-23, which may be directed against the putative HTLV-I receptor. Additional experiments revealed that the human 17q-containing hybrids could also be more efficiently infected by cell-free HTLV-I virions than could the control cell lines. Western blot analyses of cell lysates showed that recombinant HTLV-I envelope gp46 protein and Mab 34-23 both bound to proteins of approximate MW 30 and 31 kDa which were found only in the hybrid cell lines which contained human chromosome 17q. The data suggest that the gene for the HTLV-I receptor is located on the distal region of human chromosome 17q demarcated by the tk-1 locus (17q23.2-17q25.3).

Simultaneous mutations at Tyr-181 and Tyr-188 in HIV-1 reverse transcriptase prevents inhibition of RNA-dependent DNA polymerase activity by the bisheteroarylpiperazine (BHAP) U-90152s

The replacement of either Tyr-181 or Tyr-188 of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) by the corresponding HIV-2 RT amino acids Ile-181 or Leu-188 is known to result in active mutant enzymes (Y181I; Y188L) with virtual loss of sensitivity towards three structural classes of nonnucleoside RT inhibitors; L-697,661, nevirapine, and TIBO R82913. The bisheteroarylpiperazine (BHAP) U-90152S, a highly specific inhibitor (IC50, 0.29 +/- 0.01 microM) of HIV-1 RT, inhibited the recombinant Y181I and Y188L HIV-1 RT mutants with IC50 values of 3.6 +/- 0.15 microM and 0.71 +/- 0.02 microM, respectively. Construction and in vitro analysis of double mutants Y181I/Y188L and Y181C/Y188L of HIV-1 RT showed > 150-fold resistance to U-90152S. An HIV-2 RT mutant containing amino acids 176-190 from HIV-1 RT acquired full sensitivity to U-90152S (IC50, 0.26 +/- 0.01 microM). It is concluded that simultaneous mutations at Tyr-181 and Tyr-188 of HIV-1 RT promotes resistance to U-90152S.

The differential processing of homodimers of reverse transcriptases from human immunodeficiency viruses type 1 and 2 is a consequence of the distinct specificities of the viral proteases

Active, recombinant p68 reverse transcriptase (RT) from human immunodeficiency virus type 2 (HIV-2), with an NH2-terminal extension containing a hexahistidine sequence was isolated from extracts of Escherichia coli by immobilized metal affinity chromatography. Treatment of the purified p68/p68 homodimer of HIV-2 RT with recombinant HIV-2 protease generates stable, active heterodimer (p68/p58) that is resistant to further hydrolysis. Analysis of this p68/p58 HIV-2 RT heterodimer revealed that while one subunit is intact p68, the p58 subunit is COOH-terminally truncated by cleavage, not at Phe440 as is seen in processing of the p66/p66 HIV-1 RT homodimer by HIV-1 protease, but at Met484. The expected COOH-terminal p10 fragment resulting from hydrolysis of p68 at Met484 is not released intact, but undergoes further cleavage at Asn494, Met503, and Tyr532. Processing of p68/p68 HIV-2 RT with the HIV-1 protease led to cleavage of the Phe440-Tyr441 bond, exactly as is seen with p66/p66 HIV-1 RT, to give the analogous p53 subunit. Studies of a peptide substrate modeled after residues 437-444 in HIV-2 RT showed that while the HIV-1 protease was able to cleave the Phe440 bond, this bond was resistant to cleavage by the HIV-2 enzyme. Our findings provide a rationale for the previous observation that the RT heterodimer isolated from HIV-2 lysates is larger than that from HIV-1. We conclude that the p68/p58 HIV-2 RT heterodimer, containing the Met484 truncated p58 subunit, is a biologically relevant form of the enzyme in vivo.

Mechanism of resistance to U-90152S and sensitization to L-697,661 by a proline to leucine change at residue 236 of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase

Bisheteroarylpiperazines (BHAPs) are highly specific inhibitors of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT). BHAP-resistant HIV-1 is sensitized to other classes of nonnucleoside RT inhibitors and this has been primarily attributed to a proline-to-leucine substitution at amino acid 236 (P236L) of HIV-1 RT. To understand the basis for the in vitro sensitization-resistance phenomenon, single base pair mutations at amino acid P236 in HIV-1 RT were introduced to obtain P236L, P236T, P236H, P236R, and P236A HIV-1 RT mutants. Active HIV-1 RT mutants H235W, D237T, and H235W/D237T/T240K, containing substitutions from HIV-2 RT, were also cloned, expressed, and purified. Three BHAPs (U-88204E, U-87201E, and U-90125S) and the pyridinone L-697,661 were selected to quantitatively assess the effects of these amino acid substitutions on sensitization to L-697,661 and resistance to the BHAPs. The HIV-1 RT mutants bearing single (H235W; D237T) or multiple (H235W/D237T/T240K) HIV-2 RT substitutions around the conserved P236 conferred little resistance or sensitization to these RT inhibitors. The inhibition profiles of the P236 HIV-1 RT mutants demonstrated a direct correlation between sensitization to L-697,661 and resistance to the BHAPs. These results suggest alterations in the shape of the binding pocket as the mechanism by which the P236L mutation confers resistance to the BHAPs and sensitization to L-697,661.

An active recombinant p15 RNase H domain is functionally distinct from the RNase H domain associated with human immunodeficiency virus type 1 reverse transcriptase

An active p15 RNase H domain, consisting of amino acids 427-560 of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) and a genetically engineered penta-histidine N-terminal affinity tag, was expressed in Escherichia coli and purified to apparent homogeneity by immobilized metal affinity chromatography. The purified p15 RNase H domain exhibited no substrate preference for [3H]poly(rG).poly(dC) compared to [3H]poly(rA).poly(dT), in contrast with the HIV-1 RT-associated RNase H, which showed a 30-fold preference for the former substrate. Unlike the HIV-1 RT-associated RNase H, when challenged with unlabeled substrate, the recombinant p15 RNase H domain was relatively nonprocessive in RNA degradative activity of the [3H]poly(rA).poly(dT) duplex. Kinetic studies using p15 RNase H showed substrate inhibition with an apparent K(i) value of 0.12 micron for the [3H]poly(rA).poly(dT) hybrid. Substrate inhibition was not observed for the HIV-1 RT-associated RNase H. The results show that the isolated p15 HIV-1 RNase H domain is functionally distinct from the recombinant HIV-1 RT-associated RNase H.

Human immunodeficiency virus type 1 (HIV-1) recombinant reverse transcriptase. Asymmetry in p66 subunits of the p66/p66 homodimer

A recombinant p66 form of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) can be obtained [(1991) Biotechnol. Appl. Biochem. 14, 69-81] from crude Escherichia coli extracts by immobilized metal affinity chromatography (IMAC). We have analyzed the p66 HIV-1 RT, isolated in the presence of 0.3 M imidazole, by gel permeation HPLC on Superose 12. The results show that it contains two major distinct p66 forms (24.1 min and 28.3 min peaks) which are distinguishable from the purified homodimeric (p66/p66) HIV-1 RT (22.2 min peak). Protein peak 1 (24.1 min) is converted to a 22.3 min peak upon storage for 20 h at 4 degrees C. Under identical conditions, the isolated peak 2 (28.3 min) appeared as a conformationally heterogeneous mixture elaborated by peaks at 22.3 min and 25.9 min. The protein species thus obtained were active in the RNA-dependent DNA polymerase and RNase H activity assays and produced heterodimeric HIV-1 RT upon incubation with the HIV-1 protease. When the IMAC-purified, imidazole-free homodimeric (p66/p66) form of the enzyme was incubated with 0.3 M imidazole for 16 h at 4 degrees C, protein peaks at 28.3 min (peak A) and 30.5 min (peak B) were isolated by gel permeation HPLC. While both of these p66-containing species were stable and displayed identical RNA-dependent DNA polymerase activities, the protein in peak B was only 50% active in RNase H function compared with the protein from peak A. These imidazole-mediated dissociation studies support the hypothesis of partial unfolding of one of the RNase H domains of the p66/p66 homodimer, suggesting that the p66 subunits are asymmetric in the native enzyme.

Engineering of the human-immunodeficiency-virus-type-1 (HIV-1) reverse transcriptase gene to prevent dimerization of the expressed chimaeric protein: purification and characterization of a monomeric HIV-1 reverse transcriptase

We report here a human-immunodeficiency-virus-type-1 (HIV-1) recombinant reverse transcriptase (RT) engineered to contain a 26-amino-acid linker insertion from the tether domain of feline leukaemia virus (FLV) RT. The chimaeric protein was expressed in Escherichia coli and migrated on SDS/PAGE as a 68 kDa band. A monomeric form of the chimaeric HIV-1 RT has been prepared by the coordinated applications of immobilized-metal-affinity chromatography and gel filtration on Superose 12 columns. The monomeric nature of this chimaeric HIV-I RT was further characterized by cross-linking studies using disuccinimidyl suberate. The RNA-dependent DNA polymerase activity of the monomeric chimaeric HIV-1 RT was 35% that of the heterodimeric (p66/p51) HIV-1 RT. These results support our recent studies on the monomeric polymerase domain (p51 RT) which exhibited an RNA-dependent DNA polymerase activity equal to 33% of that of the p66/p51 heterodimeric HIV-1 RT (Evans, Kezdy, Tarpley and Sharma [1993] Biotechnol. Appl. Biochem. 17, 91-102). The inability of the monomeric chimaeric HIV-1 RT to display polymerase activity like that of the heterodimeric HIV-1 RT is attributed to a decrease in the processive rate of DNA synthesis (75%) and DNA binding (65%). However, the monomeric chimaeric HIV-1 RT (p68) exhibited RNAase H activity like that of the heterodimeric form (p66/p51) of HIV-1 RT. These results suggest that the linker insertion from FLV RT does not interfere with the RNAase H activity associated with the monomeric HIV-1 RT.

An unusually small gene required for sporulation by Bacillus subtilis

We report the cloning and characterization of an unusually small gene called spoVM whose product is required for normal formation of the cortex and coat during sporulation in Bacillus subtilis. The spoVM gene is adjacent to, and in convergent orientation with, the B. subtilis homologue to the Escherichia coli gene for ribosomal protein L28. The spoVM open reading frame is only 26 codons in length and is capable of encoding a polypeptide of 3 kDa. The short length of spoVM was verified by means of complementation experiments with wild-type and deletion-mutated copies of the open reading frame and by engineering the synthesis of the spoVM gene product in E. coli. Transcription of spoVM was induced during the second hour of sporulation (approximately stage II) by the appearance of the sporulation RNA polymerase sigma factor, sigma E. Efficient transcription of spoVM additionally required the action of the sporulation DNA-binding protein SpoIIID. Because spoVM was not strongly required for the transcription of several genes expressed at late times in development, its protein product is likely to play a morphogenetic rather than a regulatory role in sporulation.

Cytoplasmic phospholipase A2 activity and gene expression are stimulated by tumor necrosis factor: dexamethasone blocks the induced synthesis

The interaction of tumor necrosis factor alpha (TNF) with its two membrane-bound receptors initiates intracellular events in which arachidonic acid and its derivatives are involved. In HeLa cells, TNF treatment induces an arachidonic acid-selective, Ca(2+)-dependent cellular phospholipase A2 (cPLA2). By itself, TNF causes a modest increase in cPLA2 activity, but with the Ca2+ ionophore A23187 it provides a strong synergistic action. Within minutes in response to TNF, cPLA2 becomes phosphorylated and in the presence of Ca2+ produces a 3- to 4-fold increase in activity. TNF also increases cPLA2 mRNA and protein expression, an estimated 5-fold increase in an 8-hr period. This increase in cPLA2 activity occurs, therefore, in a biphasic time-dependent manner. Dexamethasone, known to antagonize the action of TNF, is here shown to inhibit TNF-induced gene expression and to prevent the second phase of increase in cPLA2 activation. Our results suggest that the cPLA2 activation may provide a regulatory function and may explain the proinflammatory action of TNF.

Identification of a putative cellular receptor for HTLV-I by a monoclonal antibody, Mab 34-23

The ability of HTLV-I to infect cells is presumed to be dependent, in some part, on the attachment of the virus to a target cell via a specific cell surface receptor which is, as yet, unknown. Here we present evidence that a monoclonal antibody, Mab 34-23, inhibits the binding of HTLV-I to IL-2 and phytohemagglutinin-activated peripheral blood mononuclear cells and also inhibits virus entry into these cells. Analysis of a variety of target cells, including a human:mouse somatic hybrid which contains only human chromosome 17q, indicates that the binding of Mab 34-23 correlates with HTLV-I adsorption and entry. SDS-PAGE and Western blot analysis show that Mab 34-23 binds to four major proteins of MW 31, 45, 55, and 70 kDa and this binding can be inhibited by HTLV-I and not HIV proteins. HTLV-I virions bind to proteins of similar molecular weight and virus-binding to these proteins can be inhibited by preincubation with Mab 34-23. These data suggest that Mab 34-23 may identify a specific cell surface receptor(s) for HTLV-I.

The p70 tumor necrosis factor receptor mediates cytotoxicity

Tumor necrosis factor alpha (TNF) selectively kills tumor cells, but this specificity is not clearly understood. Two distinctly different cell surface receptors (TNFRs), proteins of 55 kd (p55) and 70-80 kd (p70), mediate TNF action. Mouse TA1 cells are not killed by human (h) TNF, but are killed by mouse (m) TNF alone. Since the mouse p70 TNFR is recognized only by mTNF, these results implicate p70 receptor action in TA1 cell killing. Human HeLa cells have mainly the p55 receptor and are not killed by hTNF alone. When transfected with the human p70 TNFR, HeLa p70 die within 24 hr. HeLa p70 cells also show reduced c-fos and manganous superoxide dismutase induction by TNF. NIH 3T3 mouse fibroblasts are sensitive to only mTNF, but overexpression of the human p70 receptor causes cell death by hTNF and increased sensitivity to mTNF. These results provide a direct function for the p70 TNFR in TNF-induced cytotoxicity.

Infection of peripheral blood mononuclear cells and cell lines by cell-free human T-cell lymphoma/leukemia virus type I

Previous studies of in vitro infection by human T-cell lymphoma/leukemia virus type I (HTLV-I) have required cocultivation of target cells with HTLV-I cell lines or vesicular stomatitis virus pseudotypes containing HTLV-I envelope proteins. We report here the development of a cell-free infection assay for HTLV-I. Target cells were incubated with purified, DNase-treated HTLV-I virions for 4 h at 37 degrees C. Target cell DNA was then analyzed for the presence of newly synthesized HTLV-I proviral DNA by the highly sensitive polymerase chain reaction. Using this assay system, we have been able to consistently detect in vitro infection of a variety of cellular targets by different HTLV-I isolates. Optimal infection required the presence of 10 micrograms of DEAE-dextran per ml. The assay was dose dependent with respect to virus input. In general, the amount of proviral DNA detected correlated with the level of HTLV-I receptors present on the surface of the target cells, as measured by fluorochrome-labelled HTLV-I binding. Finally, the specificity of the assay was confirmed by demonstrating that the cell line, L1q, a somatic cell hybrid containing human chromosome 17q, to which the gene for the HTLV-I receptor has been mapped, was susceptible to infection by HTLV-I, while the parental mouse cell line from which it was derived, LMTK-, which lacks human chromosome 17q, was not.

Characterization of the Bacillus subtilis sporulation gene spoVK

The sporulation gene spoVK of Bacillus subtilis was cloned by use of the insertional mutation spoVK::Tn917 omega HU8. The spoVK gene was shown to be the site of an incorrectly mapped mutation called spoVJ517. Thus, a separate spoVJ gene as defined by the 517 mutation does not exist and is instead identical with spoVK.

Immunoassay employing surface-enhanced Raman spectroscopy

Surface-enhanced Raman scattering (SERS) was used to measure binding between biomolecules with mutual affinity, including antigen-antibody interactions. The conjugation of nitro groups onto bovine serum albumin enhanced their specific SERS activity 10(4)-fold. A dye, 2-[4'-hydroxyphenylazo]benzoic acid (HABA), with a major absorption at the Raman excitation frequency, demonstrated surface-enhanced resonance Raman scattering (SERRS) when captured from solution by avidin-coated silver films. Individual peak intensities showed a logarithmic relationship to the HABA concentration in solution over the range 10(-8) to 10(-5) M. Another resonance dye, p-dimethylaminoazobenzene (DAB) was covalently attached to an antibody directed against human thyroid stimulating hormone (TSH), without loss of antibody activity. The resultant conjugate was used in a sandwich immunoassay for TSH antigen: silver surfaces coated with anti-TSH antibody captured TSH antigen which in turn captured the DAB-anti-TSH antibody conjugate. A linear relationship was observed between the intensity of the resultant SERRS signals and the TSH antigen concentration over a range of from 4 to 60 microIU/ml. These results demonstrate the potential utility of the SERRS effect as a readout in a one-step, no wash immunoassay system.