Protection of the third-dose and fourth-dose mRNA vaccines against SARS-CoV-2 Omicron subvariant: a systematic review and meta-analysis

OBJECTIVES

The rapid spread of the SARS-CoV-2 Omicron variant has raised concerns regarding waning vaccine-induced immunity and durability. We evaluated protection of the third-dose and fourth-dose mRNA vaccines against SARS-CoV-2 Omicron subvariant and its sublineages.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Electronic databases and other resources (PubMed, Embase, CENTRAL, MEDLINE, CINAHL PLUS, APA PsycINFO, Web of Science, Scopus, ScienceDirect, MedRxiv and bioRxiv) were searched until December 2022.

STUDY ELIGIBILITY CRITERIA

We included studies that assessed the effectiveness of mRNA vaccine booster doses against SARS-CoV-2 infection and severe COVID-19 outcomes caused by the subvariant.

DATA EXTRACTION AND SYNTHESIS

Estimates of vaccine effectiveness (VE) at different time points after the third-dose and fourth-dose vaccination were extracted. Random-effects meta-analysis was used to compare VE of the third dose versus the primary series, no vaccination and the fourth dose at different time points. The certainty of the evidence was assessed by Grading of Recommendations, Assessments, Development and Evaluation approach.

RESULTS

This review included 50 studies. The third-dose VE, compared with the primary series, against SARS-CoV-2 infection was 48.86% (95% CI 44.90% to 52.82%, low certainty) at ≥14 days, and gradually decreased to 38.01% (95% CI 13.90% to 62.13%, very low certainty) at ≥90 days after the third-dose vaccination. The fourth-dose VE peaked at 14-30 days (56.70% (95% CI 50.36% to 63.04%), moderate certainty), then quickly declined at 61-90 days (22% (95% CI 6.40% to 37.60%), low certainty). Compared with no vaccination, the third-dose VE was 75.84% (95% CI 40.56% to 111.12%, low certainty) against BA.1 infection, and 70.41% (95% CI 49.94% to 90.88%, low certainty) against BA.2 infection at ≥7 days after the third-dose vaccination. The third-dose VE against hospitalisation remained stable over time and maintained 79.30% (95% CI 58.65% to 99.94%, moderate certainty) at 91-120 days. The fourth-dose VE up to 60 days was 67.54% (95% CI 59.76% to 75.33%, moderate certainty) for hospitalisation and 77.88% (95% CI 72.55% to 83.21%, moderate certainty) for death.

CONCLUSION

The boosters provided substantial protection against severe COVID-19 outcomes for at least 6 months, although the duration of protection remains uncertain, suggesting the need for a booster dose within 6 months of the third-dose or fourth-dose vaccination. However, the certainty of evidence in our VE estimates varied from very low to moderate, indicating significant heterogeneity among studies that should be considered when interpreting the findings for public health policies.

PROSPERO REGISTRATION NUMBER

CRD42023376698.

Exploring the genetic diversity of the Japanese population: Insights from a large-scale whole genome sequencing analysis

The Japanese archipelago is a terminal location for human migration, and the contemporary Japanese people represent a unique population whose genomic diversity has been shaped by multiple migrations from Eurasia. We analyzed the genomic characteristics that define the genetic makeup of the modern Japanese population from a population genetics perspective from the genomic data of 9,287 samples obtained by high-coverage whole-genome sequencing (WGS) by the National Center Biobank Network. The dataset comprised populations from the Ryukyu Islands and other parts of the Japanese archipelago (Hondo). The Hondo population underwent two episodes of population decline during the Jomon period, corresponding to the Late Neolithic, and the Edo period, corresponding to the Early Modern era, while the Ryukyu population experienced a population decline during the shell midden period of the Late Neolithic in this region. Haplotype analysis suggested increased allele frequencies for genes related to alcohol and fatty acid metabolism, which were reported as loci that had experienced positive natural selection. Two genes related to alcohol metabolism were found to be 12,500 years out of phase with the time when they began to increase in the allele frequency; this finding indicates that the genomic diversity of Japanese people has been shaped by events closely related to agriculture and food production.

SARS-CoV-2 Variants and Age-Dependent Infection Rates among Household and Nonhousehold Contacts

To determine the effects of age and variants of concern on transmission of SARS-CoV-2, we analyzed infection rates among close contacts over 4 periods in Toyama Prefecture, Japan. Among household contacts, odds of infection were 6.2 times higher during the period of the Omicron variant than during previous periods, particularly among children and adolescents.

Risk for Prison-to-Community Tuberculosis Transmission, Thailand, 2017-2020

To determine contributions of previously incarcerated persons to tuberculosis (TB) transmission in the community, we performed a healthcare facility-based cohort study of TB patients in Thailand during 2017-2020. We used whole-genome sequencing of Mycobacterium tuberculosis isolates from patients to identify genotypic clusters and assess the association between previous incarceration and TB transmission in the community. We identified 4 large genotype clusters (>10 TB patients/cluster); 28% (14/50) of the patients in those clusters were formerly incarcerated. Formerly incarcerated TB patients were more likely than nonincarcerated patients to be included in large clusters. TB patients within the large genotype clusters were geographically dispersed throughout Chiang Rai Province. Community TB transmission in the community was associated with the presence of formerly incarcerated individuals in Thailand. To reduce the risk for prison-to-community transmission, we recommend TB screening at the time of entry and exit from prisons and follow-up screening in the community.

Genome-wide host-pathogen analyses reveal genetic interaction points in tuberculosis disease

The genetics underlying tuberculosis (TB) pathophysiology are poorly understood. Human genome-wide association studies have failed so far to reveal reproducible susceptibility loci, attributed in part to the influence of the underlying Mycobacterium tuberculosis (Mtb) bacterial genotype on the outcome of the infection. Several studies have found associations of human genetic polymorphisms with Mtb phylo-lineages, but studies analysing genome-genome interactions are needed. By implementing a phylogenetic tree-based Mtb-to-human analysis for 714 TB patients from Thailand, we identify eight putative genetic interaction points (P < 5 × 10-8) including human loci DAP and RIMS3, both linked to the IFNγ cytokine and host immune system, as well as FSTL5, previously associated with susceptibility to TB. Many of the corresponding Mtb markers are lineage specific. The genome-to-genome analysis reveals a complex interactome picture, supports host-pathogen adaptation and co-evolution in TB, and has potential applications to large-scale studies across many TB endemic populations matched for host-pathogen genomic diversity.

Characteristics and Treatment Outcomes among Migrants with Pulmonary Tuberculosis: A Retrospective Cohort Study in Japan, 2009-2018

This study aimed to describe characteristics and treatment outcomes of overseas-born pulmonary tuberculosis (PTB) patients in Japan, and identify the factors associated with "treatment non-success". We conducted a retrospective analysis of overseas-born patients with drug-susceptible PTB using cohort data of PTB cases newly registered in the Japan tuberculosis (TB) surveillance system between 2009 and 2018. Overall, 9151 overseas-born PTB cases were included in this study, and 70.3% were aged 34 years old or younger. "Students of high school and higher" (28.6%) and "regular workers other than service related sectors" (28.5%) accounted for over half of the study population, and they have continued to increase. Overall, the treatment success rate was 67.1%. Transferred-out constituted the largest proportion (14.8%) among the treatment non-success rate (32.9%). Multiple logistic regression analysis revealed patients whose health insurance type was "others and unknown", including the uninsured (adjusted OR (AOR) = 3.43: 95% Confidence Intervals (CI) 2.57-4.58), those diagnosed as TB within "one year" (AOR = 2.61, 95% CI 1.97-3.46) and "1-5 years" (AOR = 2.44, 95% CI 1.88-3.17) of arrival in Japan, and males (AOR = 1.34, 95% CI 1.16-1.54), which were the main factors associated with treatment non-success. These findings imply that Japan needs to develop TB control activities considering the increasing trends of overseas-born PTB patients, the majority of whom are young and highly mobile. There is a need to pay greater attention to overseas-born PTB patients diagnosed within a short duration after entering Japan, who may be socially and economically disadvantaged for their treatment completion.

Behavioral factors associated with SARS-CoV-2 infection in Japan

Background

The relative burden of COVID‐19 has been less severe in Japan. One reason for this may be the uniquely strict restrictions imposed upon bars/restaurants. To assess if this approach was appropriately targeting high‐risk individuals, we examined behavioral factors associated with SARS‐CoV‐2 infection in the community.

Methods

This multicenter case–control study involved individuals receiving SARS‐CoV‐2 testing in June–August 2021. Behavioral exposures in the past 2 weeks were collected via questionnaire. SARS‐CoV‐2 PCR‐positive individuals were cases, while PCR‐negative individuals were controls.

Results

The analysis included 778 individuals (266 [34.2%] positives; median age [interquartile range] 33 [27–43] years). Attending three or more social gatherings was associated with SARS‐CoV‐2 infection (adjusted odds ratio [aOR] 2.00 [95% CI 1.31–3.05]). Attending gatherings with alcohol (aOR 2.29 [1.53–3.42]), at bars/restaurants (aOR 1.55 [1.04–2.30]), outdoors/at parks (aOR 2.87 [1.01–8.13]), at night (aOR 2.07 [1.40–3.04]), five or more people (aOR 1.81 [1.00–3.30]), 2 hours or longer (aOR 1.76 [1.14–2.71]), not wearing a mask during gatherings (aOR 4.18 [2.29–7.64]), and cloth mask use (aOR 1.77 [1.11–2.83]) were associated with infection. Going to karaoke (aOR 2.53 [1.25–5.09]) and to a gym (aOR 1.87 [1.11–3.16]) were also associated with infection. Factors not associated with infection included visiting a cafe with others, ordering takeout, using food delivery services, eating out by oneself, and work/school/travel‐related exposures including teleworking.

Conclusions

We identified multiple behavioral factors associated with SARS‐CoV‐2 infection, many of which were in line with the policy/risk communication implemented in Japan. Rapid assessment of risk factors can inform decision making.

Secondary transmission of SARS-CoV-2 during the first two waves in Japan: Demographic characteristics and overdispersion

Objectives

Super-spreading events caused by overdispersed secondary transmission are crucial in the transmission of COVID-19. However, the exact level of overdispersion, demographics, and other factors associated with secondary transmission remain elusive. In this study, we aimed to elucidate the frequency and patterns of secondary transmission of SARS-CoV-2 in Japan.

Methods

We analyzed 16,471 cases between January 2020 and August 2020. We generated the number of secondary cases distribution and estimated the dispersion parameter (k) by fitting the negative binomial distribution in each phase. The frequencies of the secondary transmission were compared by demographic and clinical characteristics, calculating the odds ratio using logistic regression models.

Results

We observed that 76.7% of the primary cases did not generate secondary cases with an estimated dispersion parameter k of 0.23. The demographic patterns of primary-secondary cases differed between phases, with 20–69 years being the predominant age group. There were higher proportions of secondary transmissions among older individuals, symptomatic patients, and patients with 2 days or more between onset and confirmation.

Conclusions

The study showed the estimation of the frequency of secondary transmission of SARS-CoV-2 and the characteristics of people who generated the secondary transmission.

Epidemiological factors associated with COVID-19 clusters in medical and social welfare facilities

Characteristics of COVID-19 clusters in medical and social welfare facilities, and factors associated with cluster size are still not fully understood. We reviewed COVID-19 cases identified from January 15 to April 30 of 2020 in Japan, and analyzed factors associated with cluster size in medical and social welfare facilities. In the study, COVID-19 clusters were identified in 56 medical and 34 social welfare facilities. Numbers of cases in those facilities reached their peaks after the peak of general population. Duration of occurrence of new cases in clusters showed a positive correlation with the number of cases in both types of facilities (rho = 0.44, p < 0.001; and rho = 0.69, p < 0.001, respectively). However, number of days between the first case in the prefecture and the onset of clusters showed a negative correlation with the number of cases only in clusters in social welfare facilities (rho = -0.4, p = 0.004). Our results suggested that COVID-19 cases in those facilities were prevalent in the latter phase of the community transmissions, although the underlying mechanisms for such trend could be different between medical and social welfare facilities.

Epidemiology of Coronavirus Disease 2019 in Japan: Descriptive Findings and Lessons Learned through Surveillance during the First Three Waves

Introduction

Coronavirus disease 2019 (COVID-19) has caused unprecedented global morbidity and mortality. Japan has faced three epidemic "waves" of COVID-19 from early 2020 through early 2021. Here we narratively review the three waves in Japan, describe the key epidemiologic features of COVID-19, and discuss lessons learned.

Methods

We assessed publicly available surveillance data, routine surveillance reports, and other relevant sources-multiple indicators were monitored to improve interpretation of surveillance data. Weekly trends for each wave were described based on the number of case notifications; number of tests performed; proportion of those tests that were positive for the novel coronavirus; the prevalent number of COVID-19 hospitalizations (total hospitalizations and those categorized as severe); and number of COVID-19 deaths. For each indicator and wave, we recorded the first calendar week to show an increase over two consecutive previous weeks, along with the peak week.

Results

The spring wave was characterized by detection of cases imported from China, followed by notifications of sporadic cases without travel history, clusters, and mild/asymptomatic cases. The summer wave saw a large increase in notifications and a younger age distribution, but in the context of increased testing with lower test positivity. The winter wave brought considerable morbidity and mortality, surpassing the cumulative case counts and fatalities from the earlier waves, with high peak values. Overall, relative to the first wave, the burden of severe outcomes was lower in the second and higher in the third wave, but varied by prefecture. In all three waves, severe outcomes peaked after notification counts and test positivity peaked; severe outcomes were also consistently skewed toward the elderly.

Conclusions

Important lessons were learned from each wave and across waves-some aspects remained constant, while others changed over time. In order to rapidly detect an increase in incidence, continuous, timely, and sensitive surveillance-using multiple information sources with careful interpretations-will be key in COVID-19 control.

Familial Clusters of Coronavirus Disease in 10 Prefectures, Japan, February-May 2020

The overall coronavirus disease secondary attack rate (SAR) in family members was 19.0% in 10 prefectures of Japan during February 22–May 31, 2020. The SAR was lower for primary cases diagnosed early, within 2 days after symptom onset. The SAR of asymptomatic primary cases was 11.8%.

Stillbirths, Neonatal Morbidity, and Mortality in Health-Facility Deliveries in Urban Gambia

Background: The Gambia Demographic and Health Survey 2013 data showed that up to 63% of deliveries in the country occur in health facilities. Despite such a high rate, there are few facility-based studies on delivery outcomes in the country. This analysis ancillary to a randomized control trial describes occurrence of poor pregnancy outcomes in a cohort of women and their infants delivering in a government health facility in urban Gambia. Methods: Using clinical information obtained during the trial, we calculated rates of poor pregnancy outcomes including stillbirths, hospitalization and neonatal deaths. Logistic regression was used to calculate odds ratio (OR) and 95% confidence interval (CI) in the risk factors analysis. Results: Between April 2013 and 2014, 829 mothers delivered 843 babies, including 13 stillbirths [15.4 (7.1-23.8)] per 1,000 births. Among 830 live born infants, 7.6% (n = 63) required hospitalization during the 8-week follow-up period. Most of these hospitalizations (74.6%) occurred during the early neonatal period (<7 days of life). Severe clinical infections (i.e., sepsis, meningitis and pneumonia) (n = 27) were the most common diagnoses, followed by birth asphyxia (n = 13), major congenital malformations (n = 10), jaundice (n = 6) and low birth weight (n = 5). There were sixteen neonatal deaths, most of which also occurred during the early neonatal period. Overall, neonatal mortality rate (NMR) and perinatal mortality rate (PMR) were 19.3 (CI: 9.9-28.7) per 1,000 live births and 26.1 (CI: 15.3-36.9) per 1,000 total births, respectively. Severe clinical infections and birth asphyxia accounted for 37 and 31% of neonatal deaths, respectively. The risk of hospitalization was higher among neonates with severe congenital malformations, low birth weight, twin deliveries, and those born by cesarean section. Risk of mortality was higher among neonates with severe congenital malformations and twin deliveries. Conclusion: Neonatal hospitalization and deaths in our cohort were high. Although vertical interventions may reduce specific causes of morbidity and mortality, data indicate the need for a holistic approach to significantly improve the rates of poor pregnancy outcomes. Critically, a focus on decreasing the high rate of stillbirths is warranted. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT01800942.

Roles of Children and Adolescents in COVID-19 Transmission in the Community: A Retrospective Analysis of Nationwide Data in Japan

Background: Roles of children and adolescents in spreading coronavirus disease 2019 (COVID-19) in the community is not fully understood. Methods: We analyzed the data of 7,758 children and adolescents with COVID-19 and characteristics of secondary transmission generated by these cases using case information published by local governments. Ratio of pediatric and adolescent cases generating secondary transmission was calculated for various social settings. Results: The incidence of COVID-19 was 24.8 cases per 10⁵ population aged between 0 and 9 years, and 59.2 among those aged between 10 and 19 years, which was lower than that among individuals of all age groups (79.6 per 10⁵ population) between January 15 and October 31, 2020. The proportion of cases generating secondary cases was 8.3% among infants and young children in nursery schools and kindergartens, 16% among children and adolescents attending primary schools, 34% among those attending junior high schools, 43% among those attending high schools, 31% among those attending professional training colleges, and 24% in those attending universities. Households were the most common setting for secondary transmission. Conclusion: The risk of generating secondary cases might be limited among pediatric and adolescent cases with COVID-19, especially in settings outside households. Effectiveness of traditional mitigation measures (e.g., school closures) to suppress COVID-19 transmissions should be carefully evaluated.

Clusters of Coronavirus Disease in Communities, Japan, January-April 2020

We analyzed 3,184 cases of coronavirus disease in Japan and identified 61 case-clusters in healthcare and other care facilities, restaurants and bars, workplaces, and music events. We also identified 22 probable primary case-patients for the clusters; most were 20–39 years of age and presymptomatic or asymptomatic at virus transmission.

Indo-Oceanic Mycobacterium tuberculosis strains from Thailand associated with higher mortality

SETTING: This study was conducted among tuberculosis (TB) patients in a highly endemic Thai province.OBJECTIVE: To evaluate the association between different Mycobacterium tuberculosis lineages and clinical characteristics, especially mortality.DESIGN: We enrolled 1,304 TB patients registered from 2002-2011 with culture isolates whose lineages were identified by specific regions of deletion. Data on mortality within 1 year of follow-up were extracted from the registration system and hospital records. Mortality-associated risk factors, including bacterial lineages, as independent variables were analysed using Cox regression models.RESULTS: Of 1,304 isolates, 521 (40.0%) and 582 (44.6%) belonged to Indo-Oceanic and East-Asian lineages, respectively. Indo-Oceanic strains significantly increased the mortality risk compared with East-Asian strains (adjusted hazard ratio [aHR] 1.42, 95%CI 1.02-1.99) or modern lineages (aHR 1.49, 95%CI 1.08-2.06) in the 172 patients who died within 1 year after TB diagnosis. The former also caused significantly higher mortality than modern lineages among patients who died within 6 months after TB diagnosis (aHR 1.62, 95%CI 1.12-2.35). No significant association was found between drug resistance and death.CONCLUSION: In Thailand, the Indo-Oceanic lineage of M. tuberculosis increased mortality risk compared with modern lineages or the East-Asian lineage, the latter being considered highly virulent in previous studies.

High tuberculosis burden among HIV-infected populations in Thailand due to a low-sensitivity tuberculin skin test

The current Thai guideline recommends that among people living with HIV, isoniazid preventive therapy (IPT) should be given to those with a positive tuberculin skin test (TST). We conducted a case-control study, nested within a cohort study, in Chiang Rai Province in Thailand to determine the role of TST in predicting the development of active tuberculosis (TB) within the following 2 years. Comparison between participants with CD4+ counts <50cells/mm³ to those with CD4+ ≥200cells/mm³ revealed that TST results were less sensitive (7.7% vs 50.0%) and had a lower negative predictive value (73.1% vs 97.3%) in those with a CD4+ count <50cells/mm³. In people with HIV, using a positive TST result as a criterion for initiating IPT inadvertently decreases the benefits of IPT, especially among those with low CD4+ counts.

A novel Ancestral Beijing sublineage of Mycobacterium tuberculosis suggests the transition site to Modern Beijing sublineages

Global Mycobacterium tuberculosis population comprises 7 major lineages. The Beijing strains, particularly the ones classified as Modern groups, have been found worldwide, frequently associated with drug resistance, younger ages, outbreaks and appear to be expanding. Here, we report analysis of whole genome sequences of 1170 M. tuberculosis isolates together with their patient profiles. Our samples belonged to Lineage 1-4 (L1-L4) with those of L1 and L2 being equally dominant. Phylogenetic analysis revealed several new or rare sublineages. Differential associations between sublineages of M. tuberculosis and patient profiles, including ages, ethnicity, HIV (human immunodeficiency virus) infection and drug resistance were demonstrated. The Ancestral Beijing strains and some sublineages of L4 were associated with ethnic minorities while L1 was more common in Thais. L2.2.1.Ancestral 4 surprisingly had a mutation that is typical of the Modern Beijing sublineages and was common in Akha and Lahu tribes who have migrated from Southern China in the last century. This may indicate that the evolutionary transition from the Ancestral to Modern Beijing sublineages might be gradual and occur in Southern China, where the presence of multiple ethnic groups might have allowed for the circulations of various co-evolving sublineages which ultimately lead to the emergence of the Modern Beijing strains.

Predicting the risk of pulmonary tuberculosis based on the neutrophil-to-lymphocyte ratio at TB screening in HIV-infected individuals

Background

The neutrophil to lymphocyte ratio (NL ratio) has been reported to be a predictive biomarker of tuberculosis (TB). We assessed the association between the NL ratio and the incidence of active TB cases within 1 year after TB screening among HIV-infected individuals in Thailand.

Methods

A day care center that supports HIV-infected individuals in northernmost Thailand performed TB screening and follow-up visits. We compared the baseline characteristics between the TB screening positive group and the TB screening negative group. The threshold value of NL ratio was determined by cubic-spline curves and NL ratios were categorized as high or low NL ratio. We assessed the association between NL ratio and progression to active TB within 1-year using the Cox-proportional hazard model.

Results

Of the 1064 HIV-infected individuals who screened negative for TB at baseline, 5.6% (N = 60) eventually developed TB and 26 died after TB diagnosis. A high NL ratio was associated with a higher risk of TB (adjusted hazard ratio (aHR) 2.19, 95% CI: 1.23–3.90), after adjusting for age, sex, ethnicity, CD4 counts, and other risk factors. A high NL ratio in HIV-infected individuals with normal chest X-ray predicted TB development risk. In particular, a high NL ratio with TB symptoms could predict the highest risk of TB development (aHR 2.58, 95%CI: 1.07–6.23).

Conclusions

Our results showed that high NL ratio increased the risk of TB. NL ratio combined with TB symptoms could increase the accuracy of TB screening among HIV-infected individuals.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4292-9) contains supplementary material, which is available to authorized users.

Barriers to timely administration of birth dose vaccines in The Gambia, West Africa

OBJECTIVE

Although vaccine coverage in infants in sub-Saharan Africa is high, this is estimated at the age of 6-12 months. There is little information on the timely administration of birth dose vaccines. The objective of this study was to assess the timing of birth dose vaccines (hepatitis B, BCG and oral polio) and reasons for delayed administration in The Gambia.

METHODS

We used vaccination data from the Farafenni Health and Demographic Surveillance System (FHDSS) between 2004 and 2014. Coverage was calculated at birth (0-1 day), day 7, day 28, 6 months and 1 year of age. Logistic regression models were used to identify demographic and socio-economic variables associated with vaccination by day 7 in children born between 2011 and 2014.

RESULTS

Most of the 10,851 children had received the first dose of hepatitis B virus (HBV) vaccine by the age of 6 months (93.1%). Nevertheless, only 1.1% of them were vaccinated at birth, 5.4% by day 7, and 58.4% by day 28. Vaccination by day 7 was associated with living in urban areas (West rural: adjusted OR (AOR)=6.13, 95%CI: 3.20-11.75, east rural: AOR=6.72, 95%CI: 3.66-12.33) and maternal education (senior-educations: AOR=2.43, 95%CI: 1.17-5.06); and inversely associated with distance to vaccination delivery points (≧2km: AOR=0.41, 95%CI: 0.24-0.70), and Fula ethnicity (AOR=0.60, 95%CI: 0.40-0.91).

CONCLUSION

Vaccine coverage in The Gambia is high but infants are usually vaccinated after the neonatal period. Interventions to ensure the implementation of national vaccination policies are urgently needed.

The large contribution of twins to neonatal and post-neonatal mortality in The Gambia, a 5-year prospective study

BACKGROUND

A high twinning rate and an increased risk of mortality among twins contribute to the high burden of infant mortality in Africa. This study examined the contribution of twins to neonatal and post-neonatal mortality in The Gambia, and evaluated factors that contribute to the excess mortality among twins.

METHODS

We analysed data from the Basse Health and Demographic Surveillance System (BHDSS) collected from January 2009 to December 2013. Demographic and epidemiological variables were assessed for their association with mortality in different age groups.

RESULTS

We included 32,436 singletons and 1083 twins in the analysis (twining rate 16.7/1000 deliveries). Twins represented 11.8 % of all neonatal deaths and 7.8 % of post-neonatal deaths. Mortality among twins was higher than in singletons [adjusted odds ratio (AOR) 4.33 (95 % CI: 3.09, 6.06) in the neonatal period and 2.61 (95 % CI: 1.85, 3.68) in the post-neonatal period]. Post-neonatal mortality among twins increased in girls (P for interaction = 0.064), being born during the dry season (P for interaction = 0.030) and lacking access to clean water (P for interaction = 0.042).

CONCLUSION

Mortality among twins makes a significant contribution to the high burden of neonatal and post-neonatal mortality in The Gambia and preventive interventions targeting twins should be prioritized.

Risk factors of symptomatic NSAID-induced small intestinal injury and diaphragm disease

BACKGROUND

The aetiology for nonsteroidal anti-inflammatory drug (NSAID)-induced small intestinal injuries has not been well characterised.

AIM

To determine the risk factors of symptomatic NSAID-induced small intestinal injuries, including diaphragm disease.

METHODS

Of the 1262 symptomatic patients who underwent videocapsule endoscopy and/or double-balloon enteroscopy, 156 consecutive patients were verified as having taken NSAIDs. Their CYP2C9*2, *3 and *13 single nucleotide polymorphisms (SNPs) were determined by allelic discrimination with Taqman 5'-nuclease assays.

RESULTS

Of the 156 NSAIDs users, 31 patients (20%) were diagnosed with NSAID-induced small intestinal injury. Multivariate analysis indicated that the presence of comorbidities and the use of oxicams (meloxicam, ampiroxicam and lornoxicam) or diclofenac were associated with an increased risk of NSAID-induced small intestinal injury (adjusted OR: 2.97, 95% CI: 1.05-8.41, P = 0.041 and adjusted OR: 7.05, 95% CI: 2.04-24.40, P = 0.002, respectively). The combination of aspirin and non-aspirin NSAID was more damaging than aspirin alone. Age, sex, concomitant use of proton pump inhibitors, indications for NSAIDs use, duration of NSAIDs use and CYP2C9*2, *3 and *13SNPs were unrelated. The use of meloxicam and CYP2C9*3SNPs were significantly associated with an increased risk for diaphragm disease (adjusted OR: 183.75, 95% CI: 21.34-1582.38; P < 0.0001 and adjusted OR: 12.94, 95% CI: 1.55-108.36, P = 0.018, respectively).

CONCLUSION

The use of specific NSAIDs and the factors interfering with NSAIDs metabolism might associate with small intestinal injury, especially with diaphragm disease.

Endoscopic diagnosis of follicular lymphoma with small-bowel involvement using video capsule endoscopy and double-balloon endoscopy: a case series

The aims of this study were to compare the detection rates of gastrointestinal follicular lymphoma lesions by video capsule endoscopy (VCE) and double-balloon endoscopy (DBE), and to determine the pathologic diagnostic yields of DBE-directed biopsies. A total of 27 consecutive patients were enrolled. No significant difference in detection rates was observed in 12 patients who underwent total enteroscopy at both VCE and DBE. Pathologic diagnostic yields stratified by location were 91 % in the proximal duodenum at esophagogastroduodenoscopy, 88 % in the jejunum at antegrade DBE, 52 % in the ileum at retrograde DBE, and 57 % in the terminal ileum at colonoscopy. VCE and DBE were helpful in determining treatment in 44 % of patients.

Role of endoscopic ultrasonography in predicting the response to cyclosporin A in ulcerative colitis refractory to steroids

BACKGROUND AND AIMS

Although cyclosporin A has been reported to be effective in the treatment of severe ulcerative colitis, factors predicting its therapeutic efficacy remain unclear. Technical progress in endoscopic ultrasonography has improved visualisation of the structure of the colon wall. Here, to assess the value of endoscopic ultrasonography in predicting the response to cyclosporin A treatment, we evaluated the therapeutic effect of cyclosporin A by determining the pre- and post-cyclosporin A thickness of the mucosal layer in the rectum using endoscopic ultrasonography with an ultrasonic catheter probe.

PATIENTS AND METHODS

Fifteen ulcerative colitis patients who did not respond to high-doses of corticosteroids were treated with cyclosporin A by continuous intravenous infusion at 4mg/kg/day for 20 days. Before and 20 days after cyclosporin A therapy, clinical disease activity was assessed using clinical activity index scores. Colonoscopy and endoscopic ultrasonography were undertaken before and 20 days after cyclosporin A therapy.

RESULTS

Following treatment with cyclosporin A, nine patients showed a decrease in clinical activity index score by six points or more and were defined as responders, while the other six were defined as non-responders. Endoscopic ultrasonography measurement using an ultrasonic catheter probe showed that thickness of the rectal mucosal layer before cyclosporin A was significantly greater in responders than in non-responders (p<0.05). Further, thickness after cyclosporin A was statistically decreased (p<0.01) in the responders but not in the non-responders.

CONCLUSIONS

The ultrasonic catheter probe may represent a useful means of predicting and evaluating the efficacy of cyclosporin A treatment in severely ill ulcerative colitis patients.

Clinical features of surgical resection for pulmonary metastasis from breast cancer

BACKGROUND AND OBJECTIVES

Metastatic breast cancer has been defined as a systemic disease. The discussion concerning the resection of lung metastases in patients with breast cancer is controversial. To confirm the role of resection of pulmonary metastases from breast cancer and to identify possible prognostic factors, we reviewed our institutional experience.

METHODS

Between 1991 and 2007, 41 patients with pulmonary metastases from breast cancers underwent complete pulmonary resection. All patients had obtained or had obtainable locoregional control of their primary tumors. Various perioperative variables were investigated retrospectively to confirm the role of metastasectomy and to analyze prognostic factors for overall survival after metastasectomy.

RESULTS

All patients were female with a median age of 55 years (range, 35-81 years). The overall survival rate after metastasectomy was 51% at 5 and 10 years. On multivariate analysis, fewer than four pulmonary metastases and a disease-free interval of more than 3 years were significantly favorable prognostic factors for overall survival (p=0.023 and 0.024, respectively).

CONCLUSIONS

The current practice of pulmonary metastasectomy for breast cancers in our institution was well justified. Pulmonary metastasectomy in patients with previous breast cancer might be justified when fewer than four pulmonary metastases or a disease-free interval of more than 3 years.

[Mediastinal aberrant goiter; report of a case]

A 54-year-old woman was admitted to our hospital because of an abnormal shadow on chest X-ray. Chest computed tomography (CT) scan and magnetic resonance imaging (MRI) demonstrated an anterior mediastinal tumor. The tumor was resected completely through a median sternotomy. The tumor was dissected successfully from the surrounding vessels in spite of the heavy adhesion to them. The blood supply of the tumor was from a branch of the brachiocephalic artery. The tumor was 9 x 8 x 3 cm in size, and was diagnosed as an aberrant mediastinal goiter since it showed no communication to the thyroid gland. An aberrant mediastinal goiter is a quite rare entity of diseases and its removal through the neck would result in uncontrolled blood loss because its blood supply usually derives from intrathoracic vessels.

Confocal endomicroscopy for the diagnosis of gastric cancer in vivo

BACKGROUND AND STUDY AIMS

Advances in endoscopy have led to imaging of the details of the gastric mucosa, but the histological diagnosis usually has to be confirmed by endoscopic biopsy. A method of confocal endomicroscopy that has recently been developed allows the observation of living cells in vivo. Several investigators have reported that the technique is of value, but there have as yet been no studies describing its application in gastric cancer.

PATIENTS AND METHODS

Twenty-seven patients with early gastric cancer underwent confocal endomicroscopy (Pentax EG-3870CIK; Pentax, Tokyo, Japan). After intravenous administration of fluorescein sodium, confocal images obtained from the normal mucosa and from cancerous lesions were interpreted by two pathologists independently and compared with the histological findings, including CD34 immunostaining of biopsy specimens or resected specimens from the same sites.

RESULTS

Fluorescein yielded high-quality confocal images of the gastric mucosa; if cancer could be targeted (59%) images were mostly graded good. The images corresponded to the hematoxylin-eosin staining of transverse sections of specimens from the same sites. In the results for the interpretation by the two pathologists, the accuracy for the diagnosis of gastric cancer was 94.2% (pathologist A), and 96.2% (pathologist B), respectively. The accuracy decreased substantially when poor images and inaccessible lesions were included.

CONCLUSIONS

Confocal endomicroscopy is useful in the diagnosis of gastric cancer but good quality images cannot always be obtained. In the future, it may allow virtual biopsy and help reduce unnecessary biopsies.

Melanoma differentiation-associated gene-7 (mda-7)/interleukin (IL)-24 induces anticancer immunity in a syngeneic murine model

Previous studies have shown that the human melanoma differentiation-associated gene-7 (mda-7)/interleukin-24 (IL-24) has tumor-suppressor activity in vitro and in vivo. Additionally, in vitro studies using human peripheral blood mononuclear cells indicate that mda-7/IL-24 has TH1 cytokine-like activity. However, the individual properties of mda-7/IL-24 have been previously examined separately. Thus, there is not a single study that has examined both, antitumor and proimmune properties of mda-7/IL-24. Furthermore, the tumor suppressive activity and the cytokine activity of mda-7/IL-24 have not been previously tested in an immunocompetent setting. We therefore in the present study evaluated the antitumor and immune properties of mda-7/IL-24 in a murine syngeneic tumor model. In vitro, adenovirus-mediated mda-7 gene (Ad-mda7) transfer to murine fibrosarcoma (UV2237m; MCA16) and normal (10T1/2) cells significantly inhibited growth (P=0.001) and induced apoptosis in tumor cells but not in normal cells. In vivo, intratumoral administration of Ad-mda7 resulted in significant inhibition of tumor growth (P<0.05), with a subset of mice showing complete tumor regression. We next evaluated the immune potentiation activity of Ad-mda7 in a cancer vaccine model. UV2237m cells transfected with Ad-mda7 and injected into syngeneic immunocompetent C3H mice were unable to grow; however, they did grow in immunocompromised nude mice. These tumor-free C3H mice, when challenged with parental tumor cells experienced no tumor growth, suggesting induction of systemic immunity. Moreover, splenocytes prepared from vaccinated C3H mice demonstrated higher proliferative activity and produced elevated levels of TH1 cytokines compared with those from control mice. An in vitro subset analysis of splenocytes from vaccinated mice demonstrated a significant increase in the CD3(+)CD8(+) but not the CD3(+)CD4(+) cell population (P=0.019). Thus Ad-mda7 treatment of syngeneic tumors induces tumor cell death and promotes immune activation, leading to anticancer immunity.

Preliminary comparison of capsule endoscopy and double-balloon enteroscopy in patients with suspected small-bowel bleeding

BACKGROUND AND STUDY AIMS

Capsule endoscopy (CE) and double-balloon enteroscopy (DBE) have been introduced as modalities for examining the entire small bowel. The aim of the present study was to assess the clinical effects of CE and DBE to consider the roles of CE and DBE and the indications for the procedures in patients with suspected small-bowel bleeding.

PATIENTS AND METHODS

Between June 2004 and January 2005, 32 patients in whom a site of bleeding in the gastrointestinal tract had not been identified were enrolled in the study. Twenty-eight patients were examined with both methods. Bleeding sources were categorized as either A1 lesions (immediate hemostatic procedures required) or A2 lesions (close observation required). CE and DBE were evaluated with regard to whether or not they were capable of accessing the entire small bowel and provided a diagnosis, and the access and diagnostic rates were calculated.

RESULTS

On CE, 13 patients were diagnosed with A1 lesions and six with A2 lesions; on DBE, 11 had A1 lesions and one had an A2 lesion. The access rate for the entire small intestine on CE was 90.6 % (29 of 32), significantly higher than with DBE at 62.5 % (10 of 16; P < 0.05). The diagnostic rate on CE was 59.4 % (19 of 32), higher than with DBE at 42.9 % (12 of 28; P = 0.30), but not significantly different. Among patients with A1 lesions who were diagnosed with DBE, histological diagnoses were obtained in six of the 11, and three patients were treated.

CONCLUSIONS

In many suspected small-bowel bleeding cases, CE should be selected for the initial diagnosis and DBE for treatment or histopathological diagnosis after detection of the bleeding site on CE.

Quantitative analysis of the microvascular architecture observed on magnification endoscopy in cancerous and benign gastric lesions

BACKGROUND AND STUDY AIMS

Gastric cancer remains a common malignant tumor in Japan. The aim of this study was to attempt a quantitative evaluation of the microvascular architecture observed by magnification endoscopy using image analysis, and to investigate whether this method is able to distinguish between gastric cancers and benign lesions.

PATIENTS AND METHODS

A total of 132 patients were studied using magnification endoscopy, and image analysis was performed in 71 patients (32 patients with early gastric cancer, 39 patients with benign lesions). Analysis was not possible in the other 61 patients because the quality of the image was not good enough. A square region of interest was selected from the magnified images of the gastric mucosa. From this we extracted the vascular images corresponding to microvessels and calculated the mean caliber of vessels in the region of interest.

RESULTS

Image analysis provided good-quality images of microvessels and enabled evaluation of the microvascular architecture. The mean caliber of vessels was 4.454 pixels in 17 differentiated adenocarcinomas, 4.319 pixels in 15 undifferentiated adenocarcinomas, and 4.034 pixels in the 39 benign lesions. This represented a significant difference between gastric cancers and benign lesions (P<0.0001). Histopathological investigation of surgically resected tumors demonstrated the mean caliber of microvessels in cancerous lesions to be greater than that of microvessels in the surrounding mucosa.

CONCLUSIONS

Image analysis was useful for evaluating the microvascular architecture of the gastric mucosa, and calculation of the mean caliber of the vessels may prove helpful in the differential diagnosis of gastric cancers. However, analysis was not possible in 61 of the 132 patients studied because of inadequate image quality, and this represents a significant limitation of this diagnostic method.

UFT Inhibits Lung Metastases in Spontaneous Metastasis Model of Lung Cancer

BACKGROUND

UFT, an oral 5-fluorouracil derivative, is the only drug that is effective as a postoperative adjuvant therapy for non-small cell lung cancer (NSCLC) [ ], but the mechanism of the action remains unclear. We examined whether UFT and/or its metabolite, gamma-hydroxybutyric acid (GHB) inhibits lung metastases in a mouse model.

METHODS

Lewis lung carcinoma cells were implanted into the foot pads of C57 BL/6 mice, and mice were treated with UFT or GHB.

RESULTS

Both the mean number of metastatic nodules and the mean lung weight for UFT-treated mice (11.4 and 192.1 mg, respectively) were significantly lower than those for saline-treated mice (41.5 and 415.0 mg, respectively) (p < 0.001 for both). UFT did not inhibit tumor growth at the primary sites (foot pads). No significant body weight loss was documented in UFT-treated mice. GHB did not inhibit development of lung metastases even when a higher dose was used.

CONCLUSIONS

UFT inhibits development of lung metastases without any toxicity in mouse model, which may explain the efficacy of postoperative administration of UFT for resected NSCLC.

The use of endoscopic ultrasound-guided fine-needle aspiration for investigation of submucosal and extrinsic masses of the colon and rectum

BACKGROUND AND STUDY AIM

Ensdoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) has been reported as a useful technique for histological diagnosis of submucosal or extrinsic gastrointestinal and pancreatic lesions. The aim of this study was to evaluate the use of EUS-FNA for the diagnosis of lesions either within or adjacent to the wall of the colon and rectum.

PATIENTS AND METHODS

A total of 22 patients with a lesion within the wall of, or adjacent to, the colon or rectum underwent EUS-FNA. They were divided into two groups: patients who had previously had a malignancy (the "previous +ve" group, n = 11), and patients who had not previously had a malignancy (the "previous -ve" group, n = 11). In the four patients who had lesions located proximal to the sigmoid colon, EUS-FNA was performed using a guide wire and overtube. The success rates for adequate tissue sampling and for detecting malignant and benign masses by EUS-FNA were evaluated and the success rate for detection was compared with the success rate of EUS and computed tomography.

RESULTS

Sufficient tissue for evaluation was obtained from 21 of the 22 patients (95.5 %). The overall rate of detection of malignant and benign masses was 95.5 % (21/22) for EUS-FNA and 81.8 % (18/22) for pre-EUS-FNA imaging investigations. Of the 11 patients in the previous +ve group, ten were diagnosed with recurrences of primary malignancies; of the 11 patients in the previous -ve group, four were diagnosed with primary malignancies and seven were diagnosed with benign lesions. There were no complications related to the EUS-FNA procedure.

CONCLUSIONS

EUS-FNA is a safe technique which is useful in the planning of treatment for patients who have a mass within the wall or adjacent to the wall of the entire length of the colon or rectum.

Clinical significance of caspase-3 expression in pathologic-stage I, nonsmall-cell lung cancer

Caspase-3 is a cysteine protease that plays an important role in the process of apoptotic cell death. Whereas many studies on the clinical significance of apoptosis in the therapy of malignant tumors have been reported, little has been studied clinically on caspase-3. In the present study, the clinical significance of caspase-3 expression in resected nonsmall-cell lung cancer (NSCLC) and its correlation with incidence of apoptosis were examined. A total of 118 consecutive patients who had undergone complete resection for pathologic Stage I NSCLC were retrospectively reviewed. Caspase-3 expression was examined immunohistochemically using a polyclonal antibody that recognized uncleaved caspase-3. The 5-year survival rate for patients with strong expression of caspase-3 (66.6%) was significantly lower than that for patients with weak expression (82.1%, P = 0.021). Expression of caspase-3 was not correlated with incidence of apoptosis, proliferative activity, or p53 status. Multivariate analysis confirmed that strong expression of caspase-3 was a significant factor to predict poor prognosis. These results suggest that enhanced expression of "uncleaved" caspase-3, that is, inactivated caspase-3, was correlated with poor prognosis in resected NSCLC.

A new method of segmental resection for primary lung cancer: intermediate results

OBJECTIVE

To improve the postoperative results of limited resection for small lung cancer, we have developed a new operative method, pulmonary artery-guided segmentectomy. This resection begins with identification of the pulmonary arterial branches involved in the tumor, then the pulmonary tissue is divided along the pulmonary arteries (i.e. guided by pulmonary arteries) from the hilum toward the periphery by electrocautery. The advantages of this method include the facilitation of securing adequate margin from the tumor, and the feasibility of intralobar lymph node dissection during operation. To examine the efficacy of the new method of segmental resection, we retrospectively reviewed 74 cases of T1N0M0 disease who underwent the pulmonary artery-guided segmentectomy.

METHODS

From 1993 to 2000, 74 patients with pathological T1N0M0 lung cancer were treated by the pulmonary artery-guided segmentectomy. Forty-one patients (55.4%) who underwent the segmentectomy had been considered suitable candidates for lobectomy (intentional resection group). The other 33 patients (44.6%) were considered poor candidates for lobectomy because of poor cardiopulmonary reserve (compromised resection group).

RESULTS

The overall survival rate at 5 years was 82.0%. The 5-year survivals in the intentional and the compromised resection groups were 81.6 and 77.6%, respectively, and no significant differences were detected between the groups. According to tumor size, the 5-year survival rate for patients with tumors of 20 mm or smaller (92.9%, n=53) was higher than that for the patients with tumors of 21-30 mm (63.0%, n=21), but the difference did not reach statistical significance. Median follow-up time of 27.0 months revealed eight locoregional recurrences and four deaths due to lung cancer. Sixty-three patients (85.1%) are alive with no evidence of disease, and six patients (8.1%) are alive with recurrent disease. Locoregional recurrences occurred in one of 53 patients (1.9%) with tumors 20 mm or smaller and in seven of 21 patients (33.3%) with tumors 21-30 mm, the difference being statistically significant (P<0.01).

CONCLUSIONS

Our intermediate results demonstrated that the new pulmonary artery-guided segmentectomy could be an alternative method for selected patients with small lung cancer, particularly with tumors 20 mm or smaller in diameter.

Evaluation of angiogenesis in non-small cell lung cancer: comparison between anti-CD34 antibody and anti-CD105 antibody

PURPOSE

Angiogenesis is an essential process in the progression of malignant tumors. Whereas pan-endothelial markers, such as CD34, are generally used in evaluation of angiogenesis, pan-endothelial antibodies react with not only "newly forming" vessels but also normal vessels just trapped within tumor tissues. It has been recently reported that anti-CD105 antibody preferentially reacts with "activated" endothelial cells in angiogenic tissues. Thus, the superiority of anti-CD105 monoclonal antibody (mAb) in evaluation of angiogenesis of non-small cell lung cancer (NSCLC) was assessed.

EXPERIMENTAL DESIGN

A total of 236 patients with resected NSCLC were retrospectively reviewed. Intratumoral microvessel density (IMVD) was determined with an anti-CD34 mAb (CD34-IMVD) and with an anti-CD105 mAb (CD105-IMVD).

RESULTS

The mean CD34-IMVD and CD105-IMVD were 179.9 and 41.6, respectively. Whereas CD34-IMVD was significantly correlated with the expression of vascular endothelial growth factor (P = 0.003), CD105-IMVD was more closely correlated with vascular endothelial growth factor expression (P < 0.001). The 5-year survival rate of the lower CD105-IMVD patients was 74.9%, significantly higher than that of the higher CD105-IMD patients (60.4%, P = 0.018). Whereas the 5-year survival rate of the lower CD34-IMVD patients seemed higher than that of the higher CD34-IMVD patients (63.7%), the difference did not reach a statistical significance (P = 0.137). Multivariate analysis confirmed that higher CD105-IMVD was a significant factor to predict poor prognosis (P = 0.029), whereas CD34-IMVD was not (P = 0.070).

CONCLUSIONS

Anti-CD105 mAb proved to be superior to anti-CD34 mAb in evaluation of angiogenesis in NSCLC.

Addition of ATP and MgCl2 to the preservation solution attenuates lung reperfusion injury following cold ischemia

BACKGROUND

In lung transplantation, reperfusion injury following cold ischemia is one of the crucial problems for recipients.

OBJECTIVE

We evaluated the protective effect of adding a combination of ATP and MgCl2 to the preservation solution against lung reperfusion injury following cold ischemia.

METHODS

Using an isolated rat lung perfusion model with fresh rat blood as the perfusate, the rats were divided into five groups (n = 6). In the fresh group, the study lungs were flushed with phosphate-buffered saline (PBS), then immediately reperfused for 120 min. In the control group, the study lungs were flushed with PBS, then cold ischemia was induced for 9 h (4 degrees C), after which reperfusion was performed. In the other three groups, the protocols were the same as for the control group except that ATP and/or MgCl2 were added to the PBS: ATP group (100 microM ATP), MgCl2 group (100 microM MgCl2) and ATP + MgCl2 group (100 microM ATP + 100 microM MgCl2).

RESULTS

In the ATP + MgCl2 group, the intrapulmonary shunt fraction, peak airway pressure and wet to dry lung weight ratio were significantly lower than those in the control group. No improvement was observed in the ATP or MgCl2 groups. Histological examination supported these physiological results. In all groups, flush time and lipid peroxide levels in the lungs after cold ischemia did not show any significant differences.

CONCLUSION

The addition of ATP and MgCl2 to the preservation solution attenuated reperfusion injury following cold ischemia in rat lungs.

Prognostic factors in patients with resected pathologic (p-) T1-2N1M0 non-small cell lung cancer (NSCLC)

OBJECTIVES

To clarify prognostic factors in resected pathologic (p-) T1-2N1M0 non-small cell lung cancer (NSCLC).

METHODS

A total of 95 consecutive patients who underwent complete tumor resection and mediastinal dissection for pT1-2N1M0 NSCLC between 1976 and 1997 were retrospectively reviewed. p53 status and proliferative activity were evaluated immunohistochemically.

RESULTS

The extent of N1 stations and p53 status proved to be significant prognostic factors. The 5-year survival rate for tumor without hilar node (#10) involvement was 66%, significantly higher than that for tumor with #10 involvement (39%, P<0.01). The 5-year survival rate for tumor with aberrant p53 expression was 37%, significantly lower than that for tumor without aberrant p53 expression (74%, P<0.01). There proved to be no significant difference in the prognosis between pT1 disease and pT2 disease; the 5-year survival rates for pT1 and pT2 diseases were 62 and 56%, respectively. Age, gender, performance status, grade of tumor differentiation, histological type, or proliferative activity were not significant factors. Multivariate analysis of prognostic factors using Cox's proportional hazard model confirmed these results.

CONCLUSIONS

Involvement of the hilar node and aberrant p53 expression were significant factors to predict a worse prognosis in resected T1-2N1M0 NSCLC.

Expression of neural cell adhesion molecules (polysialylated form of neural cell adhesion molecule and L1-cell adhesion molecule) on resected small cell lung cancer specimens: in relation to proliferation state

BACKGROUND AND OBJECTIVES

Alteration of homotypic cell-cell adhesion has been suggested to play an important role in tumor progression. The present study examined the relationship between neural cell adhesion molecules and state of proliferation of small cell lung cancer (SCLC) cells.

METHODS

Seventeen surgically resected specimens of SCLC were immunohistochemically examined, by using monoclonal antibodies against neural cell adhesion molecule (NCAM) and its polysialic acid side chains, and L1 cell adhesion molecule (L1-CAM). Ki-67 labeling indices were also determined immunohistochemically.

RESULTS

All patients were positive for L1-CAM. Fifteen patients (88.2%) were positive for NCAM. Among the fifteen patients, nine (60.0%) were positive for NCAM PSA side chain. The probability of survival of the NCAM without PSA side chain group was significantly higher than that of the NCAM with PSA side chain group (log-rank test; P = 0.500).

CONCLUSIONS

The expression of NCAM with PSA side chains might be a prognostic factor and NCAM a marker for SCLC. L1-CAM may be synthesized independent of state of proliferation of individual tumor cell and may affect clinical feature of SCLC.

Prognostic significance of polysialic acid expression in resected non-small cell lung cancer

Polysialic acid (PSA) is a carbohydrate attached mainly to the neural cell adhesion molecule. Because PSA is composed of a linear homopolymer of alpha-2-8-linked sialic acid residues and has a large negative charge, the presence of PSA attenuates the adhesive property of neural cell adhesion molecule and increases cellular motility. In an earlier study, we demonstrated that PSA and STX, a polysialyltransferase, were associated with tumor progression in non-small cell lung cancer (NSCLC) (F. Tanaka et al., Cancer Res., 60: 3072-3080, 2000). Therefore, in the present study, to assess the prognostic significance of PSA in resected NSCLC, a total of 236 patients who underwent complete resection for pathological (p)-stage I-IIIa disease were reviewed retrospectively. PSA was expressed in 44 of 236 (18.6%) patients, and the expression was correlated with p-stage disease. For all p-stage patients, 5-year survival rates for those with PSA-positive and PSA-negative tumors were 52.1% and 71.3%, respectively, demonstrating a significantly worse prognosis for the PSA-positive patients (P = 0.012). Analysis for only p-stage I patients also demonstrated a significantly worse prognosis for the PSA-positive patients; 5-year survival rates of the PSA-positive and the PSA-negative patients were 45.1% and 83.5%, respectively, (P < 0.001). In addition, there proved to be no difference in the postoperative survival among p-stage I, II, and IIIa patients when PSA expression was positive. Multivariate analysis confirmed that PSA expression was an independent factor to predict poor prognosis in resected NSCLC. These results suggested that PSA could be an important clinical marker and that preoperative induction and/or postoperative adjuvant therapies should be performed for PSA-positive NSCLC, even if the disease is classified as p-stage I.

Apoptosis and p53 status predict the efficacy of postoperative administration of UFT in non-small cell lung cancer

To examine whether efficacy of postoperative oral administration of UFT, a 5-fluorouracil derivative chemotherapeutic agent, may be influenced by incidence of apoptosis (apoptosis index) or apoptosis-related gene status (p53 and bcl-2) of the tumour, a total of 162 patients with pathologic stage I non-small cell lung cancer were retrospectively reviewed. UFT was administrated postoperatively to 44 patients (UFT group), and not to the other 118 patients (Control group). For all patients, 5-year survival rate of the UFT group (79.9%) seemed higher than that of the Control group (69.8%), although without significant difference (P = 0.054). For patients with higher apoptotic index, 5-year survival rate of the UFT group (83.3%) was significantly higher than that of the Control group (67.6%, P = 0.039); for patients with lower apoptotic index, however, there was no difference in the prognosis between these two groups. Similarly, UFT was effective for patients without p53 aberrant expression (5-year survival rates: 95.2% for the UFT group and 74.3% for the Control group, P = 0.022), whereas not effective for patients with p53 aberrant expression. Bcl-2 status did not influence the efficacy of UFT. In conclusion, apoptotic index and p53 status are useful factors to predict the efficacy of postoperative adjuvant therapy using UFT.

Biological features and preoperative evaluation of mediastinal nodal status in non-small cell lung cancer

BACKGROUND

To examine whether biological features of primary tumor can help preoperative evaluation of mediastinal nodal status in non-small cell lung cancer.

METHODS

A total of 450 patients who underwent tumor resection and mediastinal dissection were reviewed. p53 status and proliferative fraction (PI) were evaluated immunohistochemically.

RESULTS

The accuracy of preoperative evaluation of mediastinal nodal status with computed tomography (CT) was 72.2%; mediastinal nodal metastases had not been revealed until operation in 59 patients (13.1%) (false-negative), and no metastasis was revealed in 66 patients (14.7%) although mediastinal nodal enlargement had been demonstrated by CT (false-positive). The number of false-negative patients was significantly larger when p53 aberrant expression was positive or when PI was higher. Combined with p53 status and PI, there were 27 false-negatives (24.1%) among patients with aberrant p53 expression and higher PI, whereas only two false-negatives (1.5%) among those with negative p53 expression and lower PI.

CONCLUSIONS

Mediastinoscopy may be recommended for tumor showing aberrant p53 expression and higher PI, even when CT demonstrates no mediastinal nodal enlargement.