Effect of mechanical ventilation guided by transpulmonary pressure in acute respiratory distress syndrome patients: a systematic review and meta-analysis of randomized control trials

OBJECTIVE

This study aimed to investigate the effect of mechanical ventilation guided by transpulmonary pressure in patients diagnosed with acute respiratory distress syndrome (ARDS).

MATERIALS AND METHODS

Randomized control trials of ARDS patients that received mechanical ventilation guided by transpulmonary pressure vs. mechanical ventilation guided by traditional lung protective ventilation strategies in adults were retrieved by two reviewers independently from PubMed, EMBASE, The Cochrane Library, The China National Knowledge Infrastructure, and WanFang database before October 2022. The protocol has been registered on PROSPERO (CRD42022307816). The primary outcome was mortality. The secondary outcomes included mechanical ventilation days, oxygenation function and ventilation parameters, hemodynamics, and cytokines level.

RESULTS

Thirteen articles (819 patients) were finally included through our search strategy. The total mortality (RR, 0.68; 95% CI, 0.54-0.85; p = 0.0006) and mechanical ventilation days (MD, -2.77; 95% CI, -4.60 - -0.94; p = 0.003) reduced when compared with the control group. Patients in the transpulmonary pressure group had higher oxygen index (MD, 40.74; 95% CI 9.81-71.68, p = 0.010) and lung compliance (MD, 7.98; 95% CI 4.55-11.41, p < 0.00001). Positive end-expiratory pressure (PEEP) was higher in the transpulmonary pressure group (MD, 5.47; 95% CI, 3.59 - 7.35; p < 0.00001). The Interlukin-6 (IL-6) level in the control group decreased obviously compared with that in the transpulmonary pressure group (SMD, -2.03; 95% CI, -3.50 - -0.56; p = 0.007).

CONCLUSIONS

Mechanical ventilation guided by transpulmonary pressure tended to have a beneficial prognosis on ARDS patients. Oxygenation and lung mechanics parameters were also improved. The clinical effect of mechanical ventilation directed by transpulmonary pressure was superior to the traditional lung protective ventilation strategies in ARDS patients.

Characterization of Pd/Y multilayers with B4C barrier layers using GIXR and X-ray standing wave enhanced HAXPES

Pd/Y multilayers are high-reflectance mirrors designed to work in the 7.5-11 nm wavelength range. Samples, prepared by magnetron sputtering, are deposited with or without B₄C barrier layers located at the interfaces of the Pd and Y layers to reduce interdiffusion, which is expected from calculating the mixing enthalpy of Pd and Y. Grazing-incident X-ray reflectometry is used to characterize these multilayers. B₄C barrier layers are found to be effective in reducing Pd-Y interdiffusion. Details of the composition of the multilayers are revealed by hard X-ray photoemission spectroscopy with X-ray standing wave effects. This consists of measuring the photoemission intensity from the samples by performing an angular scan in the region corresponding to the multilayer period and an incident photon energy according to Bragg's law. The experimental results indicate that Pd does not chemically react with B nor C at the Pd-B₄C interface while Y does react at the Y-B₄C interface. The formation of Y-B or Y-C chemical compounds could be the reason why the interfaces are stabilized. By comparing the experimentally obtained angular variation of the characteristic photoemission with theoretical calculations, the depth distribution of each component element can be interpreted.

Correction: Temporal Patterns of Influenza A and B in Tropical and Temperate Countries: What Are the Lessons for Influenza Vaccination?

[This corrects the article DOI: 10.1371/journal.pone.0152310.].

Effectiveness of seasonal influenza vaccine in preventing influenza primary care visits and hospitalisation in Auckland, New Zealand in 2015: interim estimates

Preliminary results for influenza vaccine effectiveness (VE) against acute respiratory illness with circulating laboratory-confirmed influenza viruses in New Zealand from 27 April to 26 September 2015, using a case test-negative design were 36% (95% confidence interval (CI): 11–54) for general practice encounters and 50% (95% CI: 20–68) for hospitalisations. VE against hospitalised influenza A(H3N2) illnesses was moderate at 53% (95% CI: 6–76) but improved compared with previous seasons.

Interim estimates of the effectiveness of seasonal trivalent inactivated influenza vaccine in preventing influenza hospitalisations and primary care visits in Auckland, New Zealand, in 2014

We present preliminary results of influenza vaccine effectiveness (VE) in New Zealand using a case test-negative design for 28 April to 31 August 2014. VE adjusted for age and time of admission among all ages against severe acute respiratory illness hospital presentation due to laboratory-confirmed influenza was 54% (95% CI: 19 to 74) and specifically against A(H1N1)pdm09 was 65% (95% CI:33 to 81). For influenza-confirmed primary care visits, VE was 67% (95% CI: 48 to 79) overall and 73% (95% CI: 50 to 85) against A(H1N1)pdm09.

Interim estimates of the effectiveness of seasonal trivalent inactivated influenza vaccine in preventing influenza hospitalisations and primary care visits in Auckland, New Zealand, in 2014

We present preliminary results of influenza vaccine effectiveness (VE) in New Zealand using a case test-negative design for 28 April to 31 August 2014. VE adjusted for age and time of admission among all ages against severe acute respiratory illness hospital presentation due to laboratory-confirmed influenza was 54% (95% CI: 19 to 74) and specifically against A(H1N1)pdm09 was 65% (95% CI:33 to 81). For influenza-confirmed primary care visits, VE was 67% (95% CI: 48 to 79) overall and 73% (95% CI: 50 to 85) against A(H1N1)pdm09.

Effectiveness of seasonal trivalent inactivated influenza vaccine in preventing influenza hospitalisations and primary care visits in Auckland, New Zealand, in 2013

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Influenza antiviral resistance in the Asia-Pacific region during 2011

Despite greater than 99% of influenza A viruses circulating in the Asia-Pacific region being resistant to the adamantane antiviral drugs in 2011, the large majority of influenza A (>97%) and B strains (∼99%) remained susceptible to the neuraminidase inhibitors oseltamivir and zanamivir. However, compared to the first year of the 2009 pandemic, cases of oseltamivir-resistant A(H1N1)pdm09 viruses with the H275Y neuraminidase mutation increased in 2011, primarily due to an outbreak of oseltamivir-resistant viruses that occurred in Newcastle, as reported in Hurt et al. (2011c, 2012a), where the majority of the resistant viruses were from community patients not being treated with oseltamivir. A small number of influenza B viruses with reduced oseltamivir or zanamivir susceptibility were also detected. The increased detection of neuraminidase inhibitor resistant strains circulating in the community and the detection of novel variants with reduced susceptibility are reminders that monitoring of influenza viruses is important to ensure that antiviral treatment guidelines remain appropriate.

Management of acute combination atlas-axis fractures with percutaneous triple anterior screw fixation in elderly patients

INTRODUCTION

Patients with combined C1-2 fractures were often treated by posterior arthrodesis. However, elderly patients with multiple injuries (such as brain injury), the large surgical trauma of posterior arthrodesis will increase the risk of perioperative mortality. A minimally invasive technique may be better for them, and decrease the risk of perioperative mortality.

MATERIALS AND METHODS

Seven patients with combined C1-2 fractures underwent percutaneous anterior odontoid screw and anterior C1-2 transarticular screws (percutaneous triple anterior screws fixation). The surgical technique of percutaneous triple anterior screws fixation is described.

RESULTS

The operation performed on all patients successfully without technical difficulties, and no intra-operative surgery-related complications such as vertebral artery, nerve injury and soft tissue complications occurred. No pullout, loosening, or breakage of internal screws was observed. C1/2 stable was found in all cases and radiographic union achieved in all odontoid fractures.

CONCLUSION

Using the appropriate instruments allied to intra-operative image-intensification, we suggest that percutaneous triple anterior screw fixation is reliable, effective and minimally invasive procedure for elderly and brain injured patients suffering of combined atlas-axis fractures.

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Immunisation against inhibin enhances follicular development, oocyte maturation and superovulatory response in water buffaloes

This study was carried out to test the feasibility of enhancing embryo production in vivo and in vitro by immunoneutralisation against inhibin or follistatin. In Experiment 1, multi-parity buffaloes were assigned into three groups: High group (n=8), which received one primary (2mg) and two booster (1mg) vaccinations (28-day intervals) with a recombinant inhibin α subunit in 1 mL of white oil adjuvant; Low group (n=8), which received half that dose; and Control group (n=7), which received only adjuvant. Immunisation against inhibin stimulated development of ovarian follicles. Following superovulation and artificial insemination, inhibin-immunised buffaloes had more developing follicles than the Control buffaloes. The average number of embryos and unfertilised ova (4.5±0.6, n=6) in the High group was higher (P<0.05) than in the Control group (2.8±0.6, n=5) and was intermediate (4.1±0.7, n=7) in the Low group. The pooled number of transferable embryos of the High and Low groups (3.2±0.5, n=13) was also higher (P<0.05) than that (1.6±0.7, n=5) of the controls. The immunised groups also had higher plasma concentrations of activin, oestradiol and progesterone. In Experiment 2, the addition of anti-inhibin or anti-follistatin antibodies into buffalo oocyte IVM maturation medium significantly improved oocyte maturation and cleavage rates following parthenogenic activation. Treatment with anti-follistatin antibody also doubled the blastocyst yield from activated embryos. These results demonstrated that immunisation against inhibin stimulated follicular development, enhanced oocyte quality and maturation competence, yielded more and better embryos both in vivo and in vitro.

The second wave of 2009 pandemic influenza A(H1N1) in New Zealand, January–October 2010

This paper uses data from multiple surveillance systems to describe the experience in New Zealand with the second complete wave of pandemic influenza A(H1N1)2009 in 2010. Measures such as hospitalisation rates suggest the overall impact of influenza A(H1N1)2009 in 2010 was between half and two thirds that of the first wave in 2009. There was considerable regional and sub-regional variation with a tendency for higher activity in areas that experienced low rates in 2009. Demographic characteristics of the second wave were similar to those in 2009 with highest rates seen in children under the age of five years, and in indigenous M?ori and Pacific peoples. Hospital services including intensive care units were not under as much pressure as in 2009. Immunisation appears to have contributed to the reduced impact of the pandemic in 2010, particularly for those aged 60 years and older.

Genotyping assay for the identification of 2009-2010 pandemic and seasonal H1N1 influenza virus reassortants

New Zealand identified its first pandemic H1N1 influenza cases in late April 2009, immediately prior to the historical start of the New Zealand influenza season. Both pandemic and oseltamivir-resistant seasonal H1N1 viruses cocirculated in the population for a period of time. Thus, concerns were raised about the possibility of reassortment events between the two strains. An RT-PCR-based genotyping assay was developed so that H1N1 influenza coinfections and reassortants could be detected quickly. The assay differentiated effectively the seasonal and pandemic strains. It also confirmed the identification of the first reported coinfection of pandemic and seasonal H1N1 strains during the 2009 Southern Hemisphere influenza season in New Zealand.

The impact of the pandemic influenza A(H1N1) 2009 virus on seasonal influenza A viruses in the southern hemisphere, 2009

Data collected over winter 2009 by five World Health Organisation National Influenza Centres in the southern hemisphere were used to examine the circulation of pandemic and seasonal influenza A strains during the first pandemic wave in the southern hemisphere. There is compelling evidence that the pandemic influenza A(H1N1) 2009 virus significantly displaced seasonal influenza A(H1N1) and, to a lesser extent, A(H3N2) viruses circulating in the southern hemisphere. Complete replacement of seasonal influenza A strains, however, was not observed during the first pandemic wave.

The impact of the pandemic influenza A(H1N1) 2009 virus on seasonal influenza A viruses in the southern hemisphere, 2009

Data collected over winter 2009 by five World Health Organisation National Influenza Centres in the southern hemisphere were used to examine the circulation of pandemic and seasonal influenza A strains during the first pandemic wave in the southern hemisphere.There is compelling evidence that the pandemic influenza A(H1N1) 2009 virus significantly displaced seasonal influenza A(H1N1) and, to a lesser extent, A(H3N2) viruses circulating in the southern hemisphere. Complete replacement of seasonal influenza A strains, however, was not observed during the first pandemic wave.

Transmissibility of 2009 pandemic influenza A(H1N1) in New Zealand: effective reproduction number and influence of age, ethnicity and importations

The first wave of pandemic influenza A(H1N1) has subsided in New Zealand as in other southern hemisphere countries. This study aimed to estimate the effective reproduction number (R) of 2009 pandemic influenza A(H1N1) taking into account imported cases. It also aimed to show the temporal variation of R throughout the New Zealand epidemic, changes in age- and ethnicity-specific cumulative incidence, and the effect of school holidays. Using a new modelling method to account for imported cases, we have calculated the peak R during the containment phase of the pandemic as 1.55 (95% confidence interval: 1.16 to 1.86). This value is less than previously estimated in the country early in the pandemic but in line with more recent estimates in other parts of the world. Results also indicated an increase in the proportion of notifications among school-age children after the school holiday (3-19 July 2009). This finding provides support for the potential effectiveness of timely school closures, although such disruptive interventions need to be balanced against the severity of the pandemic.

Transmissibility of 2009 pandemic influenza A(H1N1) in New Zealand: effective reproduction number and influence of age, ethnicity and importations

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Interpreting Google flu trends data for pandemic H1N1 influenza: the New Zealand experience

For the period of the spread of pandemic H1N1 influenza in New Zealand during 2009, we compared results from Google Flu Trends with data from existing surveillance systems. The patterns from Google Flu Trends were closely aligned with (peaking a week before and a week after) two independent national surveillance systems for influenza-like illness (ILI) cases. It was much less congruent with (delayed by three weeks) data from ILI-related calls to a national free-phone Healthline and with media coverage of pandemic influenza. Some patterns were unique to Google Flu Trends and may not have reflected the actual ILI burden in the community. Overall, Google Flu Trends appears to provide a useful free surveillance system but it should probably be seen as supplementary rather than as an alternative.

Interpreting “Google Flu Trends” data for pandemic H1N1 influenza: The New Zealand experience

For the period of the spread of pandemic H1N1 influenza in New Zealand during 2009, we compared results from Google Flu Trends with data from existing surveillance systems. The patterns from Google Flu Trends were closely aligned with (peaking a week before and a week after) two independent national surveillance systems for influenza-like illness (ILI) cases. It was much less congruent with (delayed by three weeks) data from ILI-related calls to a national free-phone Healthline and with media coverage of pandemic influenza. Some patterns were unique to Google Flu Trends and may not have reflected the actual ILI burden in the community. Overall, Google Flu Trends appears to provide a useful free surveillance system but it should probably be seen as supplementary rather than as an alternative.

Pandemic influenza A(H1N1)v in New Zealand: the experience from April to August 2009

Following the detection of imported cases of pandemic influenza A(H1N1)v on 25 April 2009, New Zealand implemented containment measures that appeared to slow establishment of the pandemic during May. The pandemic accelerated markedly in June, reaching a peak within four to six weeks, and has been declining since mid-July. By 23 August there had been 3,179 recorded cases (97.8% reported as confirmed), including 972 hospitalisations, 114 intensive care admissions, and 16 deaths. Influenza-like illness (ILI) surveillance in general practice suggests that 7.5% (95% CI: 3.4-11.2) of the population of New Zealand had symptomatic infection, giving a case fatality ratio of 0.005%. Hospitalisations were markedly higher for Māori (age standardised relative risk (RR)=3.0, 95% CI: 2.9-3.2) and Pacific peoples (RR=6.7, 95% CI: 6.2-7.1) compared with Europeans and others. The apparent decline of the pandemic (shown by all surveillance systems) cannot be fully explained. New Zealand remains in the middle of its traditional influenza season, the influenza A(H1N1)v virus appears relatively infectious, and we estimate that only about 11% of the population have been infected by this novel agent.

Pandemic influenza A(H1N1)v viruses currently circulating in New Zealand are sensitive to oseltamivir

New Zealand, like other southern hemisphere countries with a temperate climate, has been in the winter period with seasonal influenza activity. New Zealand has also experienced a dramatic increase in the number of cases of pandemic influenza A(H1N1)v virus. Early reports from the northern hemisphere at the beginning of the pandemic showed that the virus was sensitive to the antiviral drug oseltamivir. In this study we report that pandemic influenza A(H1N1)v viruses currently circulating in New Zealand are sensitive to oseltamivir, but seasonal influenza A(H1N1) viruses - the co-circulating predominant seasonal strain, is resistant to oseltamivir.

Expression of vascular endothelial growth factor and its role in oncogenesis of human gastric carcinoma

AIM

To establish the role of vascular endothelial growth factor (VEGF) in the oncogenesis of human gastric carcinoma more directly.

METHODS

The expression of VEGF and its receptor kinase-domain insert containing receptor (KDR) in human gastric cancer tissue were observed by immunohistochemical staining. VEGF levels were manipulated in human gastric cancer cell using eukaryotic expression constructs designed to express the complete VEGF(165) complimentary DNA in either the sense or antisense orientation. The biological changes of the cells were observed in which VEGF was up-regulated or down-regulated.

RESULTS

VEGF-positive rate was 50%, and VEGF was mainly localized in the cytoplasm and membrane of the tumor cells, while KDR was mainly located in the membrane of vascular endothelial cells in gastric cancer tissues and peri-cancerous tissue. In 2 cases of 50 specimens, the gastric cancer cells expressed KDR, localized in both the cytoplasm and membrane. Introduction of VEGF(165) antisense into human gastric cancer cells (SGC-7901, immunofluorescence intensity, 31.6%)) resulted in a significant reduction in VEGF-specific messenger RNA and total and cell surface VEGF protein (immunofluorescence intensity, 8.9%) (P<0.05). Conversely, stable integration of VEGF(165) in the sense orientation resulted in an increase in cellular and cell surface VEGF (immunofluorescence intensity, 75.4%) (P<0.05). Lowered VEGF levels were associated with a marked decrease in the growth of nude mouse xenografted tumor (at 33 days postimplantation, tumor volume: 345.40 +/- 136.31 mm3)(P<0.05 vs control SGC-7901 group: 1534.40 +/- 362.88 mm3), whereas up-regulation of VEGF resulted in increased xenografted tumor size (at 33 days postimplantation, tumor volume: 2350.50 +/- 637.70 mm3) (P<0.05 vs control SGC-7901 group).

CONCLUSION

This study provides direct evidence that VEGF plays an important role in the oncogenesis of human gastric cancer.

A case of vaccine-associated paralytic poliomyelitis

Vaccine-associated paralytic poliomyelitis (VAPP) is a very rare complication of oral polio vaccine (OPV), seen predominantly with first exposure to OPV. Reversion of vaccine strain poliovirus to a more neurovirulent strain of the virus is thought to be necessary for paralytic disease to occur. Vaccine-associated poliomyelitis can occur in either recipients of the vaccine or in susceptible contacts. We describe an episode of VAPP in an infant in whom paralysis became evident at age 124 days, 14 days after administration of the second dose of OPV vaccine. The second dose of diphtheria-tetanus-pertussis- Haemophilus (DTPH) type-b vaccine had been given at the time of OPV administration, and the hepatitis B vaccine had been administered in the opposite leg. Paralysis was localized to the limb in which the DTPH had been injected.

Brain tumor volume measurement: comparison of manual and semiautomated methods

PURPOSE

To compare the reliability of two approaches to measuring enhancing brain tumor volumes--the conventional manual trace method and a threshold-based, semiautomated computer software method.

MATERIALS AND METHODS

Two operators rated contrast material-enhanced, T1-weighted axial magnetic resonance (MR) image data sets from 16 patients aged 21-71 years with high-grade gliomas. Each MR data set was rated twice by using manual tracing and twice by using the semiautomated method. The semiautomated measurement method involved a thresholding algorithm based on mixture modeling. The data collection time for each method was recorded. Reliability was measured by using inter- and intraoperator agreement indexes.

RESULTS

Mean intraoperator agreement indexes (+/- SD) were 0.90 +/- 0.09 (operator 1) and 0.83 +/- 0.15 (operator 2) for the manual trace method and 0.83 +/- 0.17 (operator 1) and 0.84 +/- 0.16 (operator 2) for the semiautomated measurement method. The mean interoperator agreement was 0.85 +/- 0.14 for the manual method and 0.82 +/- 0.18 for the semiautomated method. The semiautomated method was faster than the manual trace method by an average of 4.6 minutes per patient.

CONCLUSION

The semiautomated computer method of measuring tumor volume was faster than the manual trace method. Semiautomated computer approaches offer an alternative to manual tracing for measuring serial tumor volumes in patients with high-grade brain neoplasms.

[Observation of reconstruction of wrist joint by replacement of distal end of radius with vascularized fibular head]

OBJECTIVE

This paper is aimed to observe the long-term result of reconstruction of wrist joint by replacing distal end of radius with vascularized fibular head in patient of giant tumor.

METHODS

From July 1978 to November 1993, 12 cases of giant tumor of distal end of radius were treated by this procedure and followed up for 6 months to 15 years, and the movement range of wrist, grip strength, and pain were evaluated.

RESULTS

The painful wrist released in 11 cases, only one case still existed mild pain and felt discomfortable. The average range of movement of wrist joint was 34.05 degree in volar flexion, 52.80 degree in dorsal extension, 26.25 degree in ulnar deviation, and 19.75 degree in radial deviation, and average grip strength was 44.6 kg. Compared with the contralateral side, there were accounted for 46.2%, 72.7%, 76.1%, 80.6%, and 76.7% respectively.

CONCLUSION

Replacement of distal end of radius with fibular head to reconstruct wrist joint can restore function of carpal joint, which is proved to be a safe and effective method.

[p53 gene expression of human hepatoma cell lines and their sensitivities to parvovirus H-1]

DNA structure and expression of p53 gene in human hepatoma cell lines SMMC-7721, YY-8103 and a spontaneously transformed liver cell line L-02 were analysed using the following method: analysis of allelic losses on chromosome 17p, PCR/SSCP, Northern blot and immunoprecipitation. There was no point mutation found in the exons 4-9 of the p53 gene, and a low level of expression of p53 gene was detected in the three cell lines. These observations were in agreement to the reported results of the relevant experiment using the human hepatoma cell line QGY-7703. Sensitivities of these cell lines and other eight human hepatoma cell lines (QGY-7703, PLC/PRF/5, Tong/HCC, Huh-7, FOCUS, Hep3B, SK-Hep-1, HepG2) with known p53 backgrounds to parvovirus H-1 was assayed using MTT method. Abnormality in the structure and/or function was observed in all of the cell lines examined except HepG2. The cell line HepG2 with normal structure and function of the p53 gene was found to be the least sensitive to H-1 in comparison to all the cell lines which have defeated structure and/or function of the p53 gene. The present study serves as a preliminary evidence that enhancement of the sensitivity of human hepatoma cell lines to H-1 is correlated to the abnormality of the structure and/or function of the p53 gene.

beta-Gal enzyme activity driven by the HSV LAT promoter does not correspond to beta-gal RNA levels in mouse trigeminal ganglia

beta-Galactosidase enzyme expression can be detected in only a small percentage of trigeminal ganglia (TG) neurons acutely and latently infected with herpes simplex virus (HSV), in which the lacZ reporter gene was placed down-stream of the latency associated transcript (LAT) promoter at the LAT locus. However, DNA quantification suggests that a larger percentage of cells is infected than is expressing beta-galactosidase enzyme. To investigate the mechanism involved in regulation of genes expressed from the LAT promoter in trigeminal ganglia, in situ hybridization and histochemical staining assays were employed to determine on a cell-by-cell basis beta-gal gene expression both at the RNA and protein level. Using a LAT promoter-driven beta-gal construct in HSV-1 strain HFEM, it was found that there were 89-fold more cells positive for beta-gal transcript than cells positive for beta-gal enzyme in acutely infected trigeminal ganglia and a 10-fold difference in latently infected trigeminal ganglia. Thus, there is a discordance between beta-gal mRNA and beta-gal enzyme levels in HFEM/LAT-lacZ infected cells during acute and latent infection, and the beta-gal reporter gene activity does not faithfully compare the LAT promoter activity between acute and latently infected tissue. In contrast, in situ hybridization and histochemical staining assays were performed in mice acutely infected with a virus in which 140 bp of the LAT promoter sequences flanking the TATA element were replaced by 1.8 kbp of the neurofilament promoter (HSV-1 HFEM/NF-lacZ). This construct showed a correlation between beta-gal mRNA and enzyme expression in trigeminal ganglia in acute and latent infections. These findings suggest that sequences at the 5' end of the beta-gal transcript influence translation of the beta-gal message.

Therapy of experimental human brain tumors using a neuroattenuated herpes simplex virus mutant

BACKGROUND

Engineered herpes simplex virus (HSV) strains previously have been shown to offer a potential therapeutic alternative to conventional treatment modalities for brain tumors. Because HSV Type 1 strain 1716 has a deletion in the gamma 34.5 neurovirulence gene that renders it avirulent in the mouse central nervous system, we have assessed its potential to induce selective lysis of tumor cells versus neurons in vitro and in vivo.

EXPERIMENTAL DESIGN

To do this, we studied parental HSV-1 strain 17+ and strain 1716 using human embryonal carcinoma cells (NT2 cells). These cells resemble neuronal progenitor cells and can be induced to differentiate into neurons (NT2N) with retinoic acid. Intracerebral grafts of NT2 cells into the brains of nude mice resulted in lethal brain tumors, and grafts of NT2N cells resulted in the integration of NT2N cells.

RESULTS

In vitro studies showed that strain 1716 replicates in and spreads on monolayers of NT2 cells but not in NT2N cells. In vivo, strain 1716 replicated preferentially in NT2 tumors as evidenced by immunohistochemical staining for viral antigens, by in situ hybridization for HSV-specific transcripts, and by titration of virus from brains with tumor after intracranial injection of the virus into these mice. The temporal regression of NT2 tumors in mice treated with strain 1716 was demonstrated in vivo by magnetic resonance imaging. Electron microscopy and studies of DNA fragmentation suggested that regression of NT2 brain tumors in strain 1716-treated mice was mainly caused by a nonapoptotic, lytic mode of cell death. Finally, strain 1716-treated NT2 tumor-bearing mice survived more than twice as long as mock-treated tumor-bearing mice, and these differences in survival (25 vs. 9 weeks) were statistically significant (p < 0.03).

CONCLUSIONS

We conclude from these studies that strain 1716 induces regression of human neural tumors established in the brains of nude mice, resulting in their prolonged survival.

An in vitro ligation and transfection system for inserting DNA sequences into the latency-associated transcripts (LATs) gene of herpes simplex virus type 1

This report describes a simple, rapid and highly efficient method for introducing specific DNA sequences into a defined locus of the herpes simplex virus type 1 (HSV-1) genome by restriction enzyme cleavage and ligation. The genome of the HSV-1 strain HFEM contains a 4.1 kb deletion in one copy of the RL region, deleting one copy of the latency-associated transcript (LAT) gene. It does not contain any site for restriction enzyme PacI. Two unique PacI restriction enzyme sites flanking an HSV-1 ICP6 promoter-LacZ reporter gene cassette were engineered into the LAT region to generate a recombinant virus HFEM/ICP6-LacZ which produced blue plaques in the presence of X-gal. This viral vector allowed the insertion of foreign genes directly into the HSV-1 genome by restriction enzyme digestion and ligation. The system was tested by digesting the HFEM/ICP6-LacZ DNA with PacI and with SwaI (an endogenous unique restriction enzyme site upstream of the LAT promoter locus and inserting by in vitro ligation a LAT promoter-LacZ gene cassette into the HFEM/ICP6-LacZ genome. The new recombinant virus HFEM/LAT-LacZ was detected as white plaques in the presence of X-gal, since beta-galactosidase expression, when driven by the LAT promoter, is not detectable during viral replication in tissue culture. The high yield (approximately 100%) of the recombinant virus obtainable from this in vitro ligation and transfection procedure coupled with a blue-white or reversible white-blue plaque detection scheme makes this a powerful method for constructing HSV-1 vectors around the LAT promoter locus.(ABSTRACT TRUNCATED AT 250 WORDS)

A preliminary report on the intervention trials of primary liver cancer in high-risk populations with nutritional supplementation of selenium in China

The purpose of this study was to evaluate the effect of selenium (Se) in the prevention of human primary liver cancer. Three intervention trials were conducted among the residents at high risk to primary liver cancer (PLC) in Qidong county, Jiang-su province, the People's Republic of China. This area has the second highest rate of PLC in China. One trial was undertaken among the general population in a township with supplement of table salt fortified with 15 ppm anhydrous sodium selenite (Se-salt) for 5 y and the other four townships with similar PLC incidence rate served as the controls using normal table salt. The second trial was undertaken among hepatitis B virus surface antigen carriers (HBVsAg+) receiving supplement of 200 micrograms Se in form of selenized yeast (Se-yeast) daily vs placebo for 4 y. The third trial was carried out in members of families with high PLC incidence using Se-yeast (200 micrograms of Se daily) vs placebo for 2 y. The results showed that nutritional supplement of Se could reduce the PLC incidence significantly.