Real-world prescription of anti-COVID-19 drugs in hospitalized patients with COVID-19 in Japan

OBJECTIVE

Prescription trends and patterns of anti-COVID-19 drugs in hospitalized patients were examined based on real world data to understand the use of anti-COVID-19 drugs in clinical practice in Japan.

DESIGN

The longitudinal and cross-sectional study was conducted utilizing data from January 1, 2019 to December 31, 2021 of the MID-NET® medical information database, which stored the electronic medical records, administrative claim data, and diagnosis procedure combination data of patients in Japan.

PARTICIPANTS

Hospitalized patients with a COVID-19-related diagnosis who received at least one anti-COVID-19 drug between April 1, 2020 and December 31, 2021.

EXPOSURES

The following 14 drugs were included in this study: remdesivir, baricitinib, combination product of casirivimab and imdevimab, favipiravir, dexamethasone, ivermectin, azithromycin, nafamostat mesylate, camostat mesylate, ciclesonide, tocilizumab, sarilumab, combination product of lopinavir and ritonavir, and hydroxychloroquine.

RESULTS

We identified 5,717 patients hospitalized with COVID-19 and prescribed at least one anti-COVID-19 drug. The entire cohort generally included patients over 41-50 years and more males. The most common prescription pattern was dexamethasone monotherapy (22.9%), followed by the concomitant use of remdesivir and dexamethasone (15.0%), azithromycin monotherapy (15.0%), remdesivir monotherapy (10.2%), and nafamostat mesylate monotherapy (8.5%). However, an often prescribed anti-COVID-19 drug differed depending on the period.

CONCLUSIONS AND RELEVANCE

This study revealed the real-world situation of anti-COVID-19 drug prescriptions in hospitalized COVID-19 patients in Japan. A prescribed drug would depend on the latest scientific evidence, such as efficacy, safety, and approval status, at the time of prescription. Understanding the prescription of anti-COVID-19 drugs will be important for providing the most up-to-date treatments to patients and evaluating the benefit and/or risk of anti-COVID-19 drugs based on the utilization of an electronic medical record database.

Effect of Neuromuscular Electrical Stimulation in Patients With Critical Illness: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

Neuromuscular electrical stimulation (NMES) is used in the rehabilitation of patients with critical illness. However, it is unclear whether NMES prevents ICU-acquired weakness (ICU-AW). For this purpose, we conducted an updated systematic review and meta-analysis.

DATA SOURCES

We searched the MEDLINE, Cochrane Central Register of Controlled Trials, and Igaku Chuo Zasshi databases from April 2019 to November 2022 to identify new randomized controlled trials to the previous meta-analysis.

STUDY SELECTION

We systematically searched the literature for all randomized controlled trials on the effect of NMES in patients with critical illness.

DATA EXTRACTION

Two authors independently selected the studies and extracted data. They calculated the pooled effect estimates associated with the occurrence of ICU-AW and adverse events as primary outcomes and muscle mass change, muscle strength, length of ICU stay, mortality, and quality of life as secondary outcomes. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach.

DATA SYNTHESIS

Overall, eight studies were added to the previous 10 studies. Evidence suggests that the use of NMES reduces the occurrence of ICU-AW (six trials; risk ratio [RR], 0.48; 95% CI, 0.32-0.72); however, NMES may have little to no effect on pricking sensation in patients (eight trials; RR, 6.87; 95% CI, 0.84-56.50). NMES is likely to reduce the change in muscle mass (four trials; mean difference, -10.01; 95% CI, -15.54 to -4.48) and may increase muscle strength (six trials; standardized mean difference, 0.43; 95% CI, 0.19-0.68). Further, NMES may result in little to no difference in the length of ICU stay, and the evidence is uncertain about the effect on mortality and quality of life.

CONCLUSIONS

This updated meta-analysis revealed that the use of NMES may result in a lower occurrence of ICU-AW in patients with critical illness, but its use may have little to no effect on pricking sensation in patients.

Effects of Mobilization within 72 h of ICU Admission in Critically Ill Patients: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

Previous systematic review and meta-analysis indicates that rehabilitation within a week of intensive care unit (ICU) admission benefits physical function in critically ill patients. This updated systematic review and meta-analysis aim to clarify effects of initiating rehabilitation within 72 h of ICU admission on long-term physical, cognitive, and mental health. We systematically searched the MEDLINE, Cochrane Central Register of Controlled Trials, and Igaku Chuo Zasshi for randomized controlled trials (RCTs) between April 2019 and November 2022 to add to the previous review. Two investigators independently selected and extracted data. Pooled effect estimates for muscle strength, cognitive function, mental health after discharge, and adverse events were calculated. Evidence certainty was assessed via Grading of Recommendations, Assessment, Development, and Evaluations. Eleven RCTs were included in the meta-analysis. Early rehabilitation may improve muscle strength (three trials; standard mean difference [SMD], 0.16; 95% confidence interval [CI], -0.04-0.36) and cognitive function (two trials; SMD, 0.54; 95% CI, -0.13-1.20). Contrastingly, early mobilization showed limited impact on mental health or adverse events. In summary, initiating rehabilitation for critically ill patients within 72 h may improve physical and cognitive function to prevent post-intensive care syndrome without increasing adverse events. The effect on mental function remains uncertain.

Use of National Database of Health Insurance Claims and Specific Health Checkups for examining practical utilization and safety signal of a drug to support regulatory assessment on postmarketing drug safety in Japan

The Pharmaceuticals and Medical Devices Agency (PMDA) has conducted many pharmacoepidemiological studies for postmarketing drug safety assessments based on real-world data from medical information databases. One of these databases is the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB), containing health insurance claims of almost all Japanese individuals (over 100 million) since April 2009. This article describes the PMDA's regulatory experiences in utilizing the NDB for postmarketing drug safety assessment, especially focusing on the recent cases of use of the NDB to examine the practical utilization and safety signal of a drug. The studies helped support regulatory decision-making for postmarketing drug safety, such as considering a revision of prescribing information of a drug, confirming the appropriateness of safety measures, and checking safety signals in real-world situations. Different characteristics between the NDB and the MID-NET^® (another database in Japan) were also discussed for appropriate selection of data source for drug safety assessment. Accumulated experiences of pharmacoepidemiological studies based on real-world data for postmarketing drug safety assessment will contribute to evolving regulatory decision-making based on real-world data in Japan.

Cardiovascular risk of urate-lowering drugs: A study using the National Database of Health Insurance Claims and Specific Health Checkups of Japan

In the present study, we aimed to investigate the association between urate-lowering drugs and cardiovascular events, primarily focusing on the risk of febuxostat and topiroxostat when compared with allopurinol in Japan. We conducted an observational study with a cohort design using the National Database of Health Insurance Claims and Specific Health Checkups of Japan, including new urate-lowering drugs users between August 1, 2010, and March 31, 2018. Exposure and control groups were defined based on the first prescription of urate-lowering drugs as follows: febuxostat or topiroxostat for exposure groups, allopurinol for the control group, and benzbromarone for the secondary control group. The primary outcome was cardiovascular events, defined as a composite of acute coronary syndrome, cerebral infarction, and cerebral hemorrhage. Hazard ratios were estimated using a Cox proportional hazards model. The number of patients in each exposure and control group was 1,357,671 in the febuxostat group, 83,683 in the topiroxostat group, 1,273,211 in the allopurinol group, and 258,786 in the benzbromarone group. The adjusted hazard ratios for the cardiovascular risk were 0.97 (95% confidence interval [CI]: 0.95-0.98) for febuxostat and 0.84 (95% CI: 0.78-0.90) for topiroxostat groups. The benzbromarone group exhibited similar results. No increased cardiovascular risk was observed with febuxostat or topiroxostat when compared with allopurinol in patients with hyperuricemia in Japan. These results provide real-world evidence regarding the cardiovascular risk associated with urate-lowering drugs, indicating that no additional safety-related regulatory actions are warranted in Japan.

Laypersons' Psychological Barriers Against Rescue Actions in Emergency Situations - A Questionnaire Survey

BACKGROUND

Although bystanders' performance is important to improve outcomes of patients after cardiac arrests, few studies have investigated the barriers of bystanders, including those who could not perform cardiopulmonary resuscitation or any other rescue actions in emergency situations. This study aimed to assess the relationship between the psychological barriers of laypersons who encountered emergency situations and their rescue actions.Methods and Results:A questionnaire survey was conducted and this included laypersons who had encountered emergency situations during the last 5 years. Six questions were about the psychological barriers and 8 questions were about the laypersons' rescue actions. The primary outcome was any rescue actions performed by laypersons in an actual emergency situation. Overall, 7,827 (92.8%) of 8,430 laypersons responded; of them, 1,361 (16.1%) had encountered emergency situations during the last 5 years, and 1,220 (14.5%) were eligible for inclusion in the analyses. Of the 6 psychological barriers, "fear of approaching a collapsed person" (adjusted odds ratio [AOR] 0.50; 95% confidence interval [95% CI] 0.32-0.79) and "difficulties in judging whether to perform any rescue action" (AOR 0.63; 95% CI 0.40-0.99) were significantly associated with performing any rescue actions.

CONCLUSIONS

The fear of approaching a collapsed person and difficulties in judging whether to take any actions were identified as the psychological barriers in performing any rescue actions by laypersons who encountered emergency situations.

Effectiveness of a digital device providing real-time visualized tooth brushing instructions: A randomized controlled trial

Introduction

The aim of this trial was to investigate whether a digital device that provides real-time visualized brushing instructions would contribute to the removal of dental plaque over usual brushing instructions.

Methods

We conducted a single-center, parallel-group, stratified permuted block randomized control trial with 1:1 allocation ratio. Eligibility criteria included people aged ≥ 18 years, and exclude people who met the following criteria: severely crowded teeth; using interdental cleaning implement; having external injury in the oral cavity, or stomatitis; having less than 20 teeth; using orthodontic apparatus; visited to a dental clinic; having the possibility of consulting a dental clinic; having a dental license; not owning a smartphone or tablet device; smoker; taken antibiotics; pregnant; an allergy to the staining fluid; and employee of Sunstar Inc. All participants received tooth brushing instructions using video materials and were randomly assigned to one of two groups for four weeks: (1) an intervention group who used the digital device, providing real-time visualized instructions by connection with a mobile application; and (2) a control group that used a digital device which only collected their brushing logs. The primary outcome was the change in 6-point method plaque control record (PCR) score of all teeth between baseline and week 4. The t-test was used to compare the two groups in accordance with intention-to-treat principles.

Results

Among 118 enrolled individuals, 112 participants were eligible for our analyses. The mean of PCR score at week 4 was 45.05% in the intervention group and 49.65% in the control group, and the change of PCR score from baseline was −20.46% in the intervention group and −15.77% in the control group (p = 0.088, 95% confidence interval −0.70–10.07).

Conclusions

A digital device providing real-time visualized brushing instructions may be effective for the removal of dental plaque.

Prehospital cardiopulmonary resuscitation duration and neurological outcome after adult out-of-hospital cardiac arrest by location of arrest

BACKGROUND

Little is known about the association between prehospital cardiopulmonary resuscitation duration for adults with out-of-hospital cardiac arrest and outcome by the location of arrests. This study aimed to investigate the association between prehospital cardiopulmonary resuscitation duration and one-month survival with favourable neurological outcome.

METHODS

We analysed 276,391 adults aged 18 years and older with out-of-hospital cardiac arrest of medical origin before emergency medical service arrival. Prehospital cardiopulmonary resuscitation duration was defined as the time from emergency medical service-initiated cardiopulmonary resuscitation to prehospital return of spontaneous circulation or to hospital arrival. The primary outcome was one-month survival with favourable neurological outcome (cerebral performance category 1 or 2). The association between prehospital cardiopulmonary resuscitation duration and favourable neurological outcome was assessed using univariable and multivariable logistic regression analyses.

RESULTS

The proportion of favourable neurological outcomes was 2.3% in total, 7.6% in public locations, 1.5% in residential locations and 0.7% in nursing homes (P < 0.001). In univariable and multivariable logistic regression analyses, longer prehospital cardiopulmonary resuscitation duration was associated with poor neurological outcome, regardless of arrest location (P for trend < 0.001). Patients with shockable rhythm in both public and residential locations had better neurological outcome than those in nursing homes at any time point, and residential and public locations had a similar neurological outcome tendency among patients with shockable rhythm.

CONCLUSIONS

Longer prehospital cardiopulmonary resuscitation duration was independently associated with a lower proportion of patients with favourable neurological outcomes. Moreover, the association between prehospital cardiopulmonary resuscitation duration and neurological outcome differed according to the location of arrest and the first documented rhythm.

Prehospital cardiopulmonary resuscitation duration and neurological outcome after out-of-hospital cardiac arrest among children by location of arrest: a Nationwide cohort study

BACKGROUND

Little is known about the associations between the duration of prehospital cardiopulmonary resuscitation (CPR) by emergency medical services (EMS) and outcomes among paediatric patients with out-of-hospital cardiac arrests (OHCAs). We investigated these associations and the optimal prehospital EMS CPR duration by the location of arrests.

METHODS

We included paediatric patients aged 0-17 years with OHCAs before EMS arrival who were transported to medical institutions after resuscitation by bystanders or EMS personnel. We excluded paediatric OHCA patients for whom CPR was not performed, who had cardiac arrest after EMS arrival, whose EMS CPR duration were < 0 min or ≥120 min and who had cardiac arrest in healthcare facilities. Prehospital EMS CPR duration was defined as the time from CPR initiation by EMS personnel to the time of prehospital return of spontaneous circulation or to the time of hospital arrival. The primary outcome was 1-month survival with a favourable neurological outcome (cerebral performance category scale 1 or 2). Statistical analysis was performed with Mann-Whitney U tests for numerical variables and chi-squared test for categorical variables. Univariable and multivariable logistic regression analyses were applied to assess the association between prehospital EMS CPR duration and a favourable neurological outcome, and crude and adjusted odds ratios and their 95% confidence intervals were calculated.

RESULTS

The proportion of patients with a favourable neurological outcome was lower in residential locations than in public locations (2.3% [66/2865] vs 10.8% [113/1048]; P < .001). In both univariable and multivariable logistic regression analyses, the proportion of patients with a favourable neurological outcome decreased as prehospital EMS CPR duration increased, regardless of the location of arrests (P for trend <.001). However, some patients achieved a favourable neurological outcome after a prolonged prehospital EMS CPR duration (> 30 min) in both groups (1.4% [6/417] in residential locations and 0.6% [1/170] in public locations).

CONCLUSIONS

A longer prehospital EMS CPR duration is independently associated with a lower proportion of patients with a favourable neurological outcome. The association between prehospital EMS CPR duration and neurological outcome differed significantly by location of arrests.

Public-access automated external defibrillator pad application and favorable neurological outcome after out-of-hospital cardiac arrest in public locations: A prospective population-based propensity score-matched study

BACKGROUND

Randomized controlled trials or observational studies showed that the use of public-access automated external defibrillator (AED) was effective for patients with out-of-hospital cardiac arrest (OHCA). However, it is unclear whether public-access AED use is effective for all patients with OHCA irrespective of first documented rhythm. We aimed to evaluate the effect of public-access AED use for OHCA patients considering first documented rhythm (shockable or non-shockable) in public locations.

METHODS

From the Utstein-style registry in Osaka City, Japan, we obtained information on adult patients with OHCA of medical origin in public locations before emergency-medical-service personnel arrival between 2011 and 2015. Primary outcome was 1-month survival with favorable neurological outcome. Multivariable logistic regression analysis was performed to assess the association between the public-access AED pad application and favorable neurological outcome after OHCA by using one-to-one propensity score matching analysis.

RESULTS

Among 1743 eligible patients, a total of 336 (19.3%) patients received public-access AED pad application. The proportion of patients who survived 1-month with favorable neurological outcome was significantly higher in the pad application group than in the non-pad application group (29.8% vs. 9.7%; adjusted odds ratio [AOR], 2.85; 95% confidence interval [CI], 1.73-4.68, AOR after propensity score matching, 2.46; 95% CI, 1.29-4.68). In a subgroup analysis, the AORs of patients with shockable or non-shockable rhythms were 3.36 (95% CI, 1.78-6.35) and 2.38 (95% CI, 0.89-6.34), respectively.

CONCLUSIONS

Public-access AED pad application was associated with better outcome among patients with OHCA of medical origin in public locations irrespective of first documented rhythm.

Intra-aortic balloon pump and survival with favorable neurological outcome after out-of-hospital cardiac arrest: A multicenter, prospective propensity score-matched study

OBJECTIVES

This study aimed to evaluate whether intra-aortic balloon pump (IABP) use in nontraumatic out-of-hospital cardiac arrest (OHCA) patients who achieved return of spontaneous circulation (ROSC) is associated with favorable neurological outcome after OHCA.

BACKGROUND

The association between the IABP use in OHCA patients and favorable neurological outcome has not been extensively evaluated.

METHODS

The Comprehensive Registry of Intensive Cares for OHCA Survival (CRITICAL) study, a multicenter, prospective observational registry in Osaka, Japan, included consecutive nontraumatic OHCA patients aged ≥18 years who achieved ROSC from July 2012 to December 2016. The primary outcome was 1-month survival with favorable neurological outcome. Logistic regression analysis was used to evaluate the association between the IABP use or non-IABP use and favorable neurological outcome using one-to-one propensity score (PS) matching analysis.

RESULTS

Among the 2894 eligible patients, 10.4% used IABP, and 89.6% did not use IABP. In all patients, the proportion of 1-month survival with favorable neurological outcome was higher in the IABP use group than in the non-IABP use group (30.7% [92/300] vs. 13.2% [342/2594]). However, in PS-matched patients, the proportions of 1-month survival with favorable neurological outcome were almost consistent, and there were no significant differences between the IABP use group and the non-IABP use group (37.3% [59/158] vs. 41.1% [65/158]; adjusted odds ratio, 0.97; 95% confidence interval, 0.48-1.96).

CONCLUSIONS

In this population, the current PS matching analysis did not reveal any association between the IABP use and 1-month survival with favorable neurological outcome among adult patients with ROSC after OHCA.

Serum potassium level on hospital arrival and survival after out-of-hospital cardiac arrest: The CRITICAL study in Osaka, Japan

BACKGROUND

Little is known about the association between serum potassium level on hospital arrival and neurological outcome after out-of-hospital cardiac arrest (OHCA). We investigated whether the serum potassium level on hospital arrival had prognostic indications for patients with OHCA.

METHODS

This prospective, multicenter observational study conducted in Osaka, Japan (CRITICAL study) enrolled consecutive patients with OHCA transported to 14 participating institutions from 2012 to 2016. We included adult patients aged ⩾18 years with OHCA of cardiac origin who achieved return of spontaneous circulation and whose serum potassium level on hospital arrival was available. Based on the serum potassium level, patients were divided into four quartiles: Q1 (K ⩽3.8 mEq/L), Q2 (3.8< K⩽4.5 mEq/L), Q3 (4.5< K⩽5.6 mEq/L) and Q4 (K >5.6 mEq/L). The primary outcome was one-month survival with favorable neurological outcome, defined as cerebral performance category scale 1 or 2.

RESULTS

A total of 9822 patients were registered, and 1516 of these were eligible for analyses. The highest proportion of favorable neurological outcome was 44.8% (189/422) in Q1 group, followed by 30.3% (103/340), 11.7% (44/375) and 4.5% (17/379) in the Q2, Q3 and Q4 groups, respectively (p<0.001). In the multivariable analysis, the proportion of favorable neurological outcome decreased as the serum potassium level increased (p<0.001).

CONCLUSIONS

High serum potassium level was significantly and dose-dependently associated with poor neurological outcome. Serum potassium on hospital arrival would be one of the effective prognostic indications for OHCA achieving return of spontaneous circulation.

On the molecular organization, diversity and functions of desmosomal proteins

After a brief review of epithelial cell junctions, the authors describe a series of observations and experiments directed toward elucidating the molecular organization and functions of the proteins of desmosomes (maculae adherentes). Their immunofluorescence observations reveal differences between the proteins of junctional complex and other desmosomes of the same cells. Quantitative immuno-localization studies are described using protein A-colloidal gold markers and a series of monospecific, polyclonal antibodies directed against cytokeratins and four desmosomal protein families. It is shown that desmoplakin III (about 81 kDa) is restricted to the desmosomal cytoplasmic plaque, which possesses outer and inner dense zones. Desmoplakins I/II (about 240 kDa and 210 kDa) extend across the same range and beyond into the intermediate filament-rich cytoplasm. Two glycoprotein families, desmoglein I (DGI; about 150 kDa) and desmoglein II (DGII; about 97-118 kDa), extend from the desmosomal midline (or beyond) across the desmoglea (intercellular space), through the plasma membrane and across both layers of the plaque, terminating near its cytoplasmic border. Cytokeratins do not extend into the desmosome. With new procedures utilizing guanidine HCl for preparing and fractionating desmosomal proteins, DGII has been purified to homogeneity. DGII, DGI and a third protein are all shown to bind Ca2+, which is known to promote desmosome assembly.

Rat CRM1 is responsible for the poor activity of human T-cell leukemia virus type 1 Rex protein in rat cells

Rat models of human T-cell leukemia virus type 1 (HTLV-1)-related diseases such as adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis have been reported. However, these models do not completely reproduce human diseases partly because HTLV-1 replicates poorly in rats. We investigated here the possible reason for this. We found that the activity of Rex in rat cells is quite low compared to that in human cells. As Rex function depends largely on the CRM1 protein, whose human type (human CRM1 [hCRM1]) directly binds to Rex and exports it from the nucleus to the cytoplasm, we assessed whether rat CRM1 (rCRM1) could act as well as hCRM1 as a cofactor for Rex activity. We first cloned a cDNA encoding rCRM1 and found that both rCRM1 and hCRM1 could bind to and export Rex protein to the cytoplasm with similar efficiencies. However, unlike hCRM1, rCRM1 could hardly support Rex function because of its poor ability in inducing the Rex-Rex interaction required for RNA export into the cytoplasm. These observations suggest that the poor ability of rCRM1 to act as a cofactor for Rex function may be responsible for the poor replication of HTLV-1 in rats.

Sequence analysis of fibroblast growth factor receptor 2 ( FGFR2 ) in Japanese patients with craniosynostosis

Recently, mutations of the fibroblast growth factor receptor ( FGFR ) genes have been detected in syndromic craniosynostosis. We examined nucleotide sequences of FGFR2 in Japanese craniosynostosis patients (Crouzon syndrome: 9 cases; Apert syndrome: 6 cases; scaphocephaly: 3 cases as non-syndromic patients) by polymerase chain reaction (PCR) followed by direct sequencing methods. The results demonstrated FGFR2 heterozygous mutations at codons 252, 290 of exon 7, and at codon 342, 354 of exon 9 in Crouzon syndromes. In Apert syndrome patients, Ser252Trp and Pro253Arg were detected in five and one patients, respectively. No mutation was detected in one case of Crouzon, all cases of scaphocephaly and healthy individuals. Thus far sequence analysis of FGFR2 in syndromic craniosynostosis has been reported in many white patients, whereas in Japanese only several cases have been studied. The current study with 18 patients confirmed that a similar series of mutations occur in Japanese patients as in white patients regardless of ethnicity and environment. The frequency of the mutation was 82% (9/11 cases) in Japanese Crouzon patients. The ratio of S252W:P253R was 5 : 1 in Japanese Apert patients. Moreover, in Japanese Apert patients, complication rate of cleft palate was 60% for mutation of Ser252Trp and 0 of 2 patients for Pro253Arg, with their syndactyly score being 4.90 and 5.50, respectively.

Dox-dependent SIVmac with tetracycline-inducible promoter in the U3 promoter region

An attenuated live vaccine is a candidate in developing vaccines against human immunodeficiency virus type 1 (HIV-1). The study using macaques and simian immunodeficiency virus (SIVmac) showed an attenuated virus to be more effective than any other vaccine candidate. However, development of a safer vaccine is required for clinical application. In this study, we constructed pSIVmac Delta nef with tetracycline inducible promoter (pTet) and tried to control viral expression in a drug-dependent manner. Promoter/enhancer motifs in the U3 region of the long terminal repeats (LTRs) were serially deleted and replaced with pTet. In mutant LTRs, which lack NF-kappaB and Sp1 binding sites, TATA box motifs, and the 5' half of the U3 region, promoter activity was stringently controlled by doxycycline (Dox). Their activities were similar to or higher than that of wild-type LTR in the presence of Dox, based on the transient chloramphenicol acetyltransferase reporter assay. Three of these mutant LTRs were introduced into the pSIVmac239 Delta nef genome. Viral protein from these viruses was efficiently expressed in a Dox-dependent manner after transfection to a HeLa cell, which expresses reverse tetracycline transactivator (rtTA). The 2-LTR-form viral DNA of these viruses could be detected in M8166 cells that had been infected with supernatants from the transfected rtTA HeLa cell. These results suggest that pSIVmac Delta nef containing mutant LTRs can proceed through one viral replication cycle consisting of transcription, formation of viral particles, infection to cells, and reverse transcription. Although continuous replication of these Dox-dependent viruses requires a supply of rtTA as a constituent for the pTet-On viral genome, the successful replacement of the original promoter with a drug-dependent promoter suggests a new possibility for developing a safer attenuated live virus.

Induction of recombinant gene expression in stably transfected cell lines using attenuated vaccinia virus MVA expressing T7 RNA polymerase with a nuclear localisation signal

There are major drawbacks using vaccinia virus (VV) expressing T7 polymerase for eukaryotic expression. VV is infectious for humans and due to cytosolic replication of Poxviridae, transient transfection of T7 promoter containing plasmids is necessary, which varies in efficiency. Several improvements have been introduced to this system to enhance expression of herpes viral glycoproteins. Stably transfected cell lines were generated with an EBV-based episomal plasmid vector which can be pushed to increasing copy numbers under selective pressure. The avirulent vaccine MVA strain was adopted to generate a safe laboratory vector for inserting the bacteriophage T7 RNA polymerase gene with (+) or without (-) a nuclear localisation signal. Constructs were designed for recombination into the VV haemagglutinin gene as recombinants could not be isolated successfully when inserting into the MVA thymidine kinase locus. Both T7 MVA recombinants induced foreign protein expression in transiently transfected cells but only the T7-/+ MVA induced target protein expression in stably transfected cells. The level of protein expression by this induction mechanism was comparable to, or superior to levels obtained with VV recombinants expressing the gene under control of the VV 11 k IE promoter. The results suggests that the T7+ MVA virus can be used to induce gene expression in stable recombinant cell lines and offers an attractive and safe alternative to other inducible eucaryotic expression systems.

Mixed dust fibrosis and tuberculosis in comparison with silicosis and macular pneumoconiosis

BACKGROUND

To assess the relationship between mixed dust fibrosis (MDF) and tuberculosis.

METHODS

We performed a comparative analysis with MDF, silicosis, and macular pneumoconiosis (Mac), using autopsy records from 1975 to 1994.

RESULTS

Prevalences of having tuberculosis among MDF, silicosis, and Mac were not significantly different, albeit a tendency of higher prevalence in silicosis. Cure rates of tuberculosis were, in order, silicosis < MDF < Mac (P=0. 085). Death rates associated with tuberculosis were, in order, silicosis > MDF=Mac (P=0.911). With respect to the two types of association with tuberculosis, i.e., combined type (tuberculopneumoconiosis) and complicated one (pneumoconiosis with tuberculosis); the former was significantly dominant in silicosis, the latter was significantly dominant in Mac, and intermediate in MDF. As a whole, the complicated type had a tendency of a higher cure rate than the combined type (P=0.071). Although the differences of profiles between the combined and complicated types were not statistically significant, the combined type had a tendency to have longer duration of exposure to dusts, earlier registration for treatment, higher profusion score, and earlier death compared with the complicated type.

CONCLUSIONS

From our findings, MDF takes an intermediate position between silicosis and Mac regarding the relationship with tuberculosis. The type of association with tuberculosis rather than the kind of background pneumoconiosis seemed to be more important in light of responsiveness to the treatment.

Protective effects against simian immunodeficiency virus agm (SIVagm) infection in cynomolgus monkeys immunized with a recombinant vaccinia virus expressing the SIVagm envelope gene

Protective immunity induced by a recombinant vaccinia virus expressing the envelope (Env) protein of a simian immunodeficiency virus strain, SIVagm, (SEN-RVV), was evaluated in cynomolgus monkeys (Macaca fascicularis). Three monkeys were immunized twice with SEN-RVV and boostered with the purified SIVagm Env protein. These monkeys developed high titers of anti-SIVagm Env antibody, especially after boostering. After challenge with polyclonal SIVagm, no virus was recovered from two of the monkeys and no provirus DNA was detected in one of these two. After autopsy, however, proviral DNA was detected in the spleen of this monkey. These results suggest that this immunization regimen could not completely protect the monkeys from SIV infection but that it did reduce the replicability of the challenged virus.

Inhibitory mechanism of the CXCR4 antagonist T22 against human immunodeficiency virus type 1 infection

We recently reported that a cationic peptide, T22 ([Tyr(5,12), Lys(7)]-polyphemusin II), specifically inhibits human immunodeficiency virus type 1 (HIV-1) infection mediated by CXCR4 (T. Murakami et al., J. Exp. Med. 186:1389-1393, 1997). Here we demonstrate that T22 effectively inhibits replication of T-tropic HIV-1, including primary isolates, but not of non-T-tropic strains. By using a panel of chimeric viruses between T- and M-tropic HIV-1 strains, viral determinants for T22 susceptibility were mapped to the V3 loop region of gp120. T22 bound to CXCR4 and interfered with stromal-cell-derived factor-1alpha-CXCR4 interactions in a competitive manner. Blocking of anti-CXCR4 monoclonal antibodies by T22 suggested that the peptide interacts with the N terminus and two of the extracellular loops of CXCR4. Furthermore, the inhibition of cell-cell fusion in cells expressing CXCR4/CXCR2 chimeric receptors suggested that determinants for sensitivity of CXCR4 to T22 include the three extracellular loops of the coreceptor.

Determinant in human immunodeficiency virus type 1 for efficient replication under cytokine-induced CD4(+) T-helper 1 (Th1)- and Th2-type conditions

Cytokines are potent stimuli for CD4(+)-T-cell differentiation. Among them, interleukin-12 (IL-12) and IL-4 induce naive CD4(+) T cells to become T-helper 1 (Th1) or Th2 cells, respectively. In this study we found that macrophage-tropic human immunodeficiency virus type 1 (HIV-1) strains replicated more efficiently in IL-12-induced Th1-type cultures derived from normal CD4(+) T cells than did T-cell-line-tropic (T-tropic) strains. In contrast, T-tropic strains preferentially infected IL-4-induced Th2-type cultures derived from the same donor CD4(+) T cells. Additional studies using chimeric viruses demonstrated that the V3 region of HIV-1 gp120 was the principal determinant for efficiency of replication. Cell fusion analysis showed that cells expressing envelope protein from a T-tropic strain effectively fused with IL-4-induced Th2-type culture cells. Flow cytometric analysis showed that the level of CCR5 expression was higher on IL-12-induced Th1-type culture cells, whereas CXCR4 was highly expressed on IL-4-induced Th2-type culture cells, although a low level of CXCR4 expression was observed on IL-12-induced Th1-type culture cells. These results indicate that HIV-1 isolates exhibit differences in the ability to infect CD4(+)-T-cell subsets such as Th1 or Th2 cells and that this difference may partly correlate with the expression of particular chemokine receptors on these cells. The findings suggest that immunological conditions are one of the factors responsible for inducing selection of HIV-1 strains.

Intracellular localization and release of eotaxin from normal eosinophils

Eotaxin is a potent and selective CC chemokine for eosinophils and basophils. We established several monoclonal antibodies (Mabs) allowing the neutralization and measurement of human eotaxin. Using the Mabs as probes, we demonstrated that normal eosinophils contained intracellular granule-associated eotaxin. Quantification of cell-associated eotaxin in different leukocyte subsets revealed that it was principally expressed in eosinophils. Finally, we showed that normal eosinophils released eotaxin upon stimulation with either of two secretagogues, C5a or ionomycin. These findings raise the possibility that eosinophil-derived eotaxin contributes to the local accumulation of eosinophils at the site of inflammation.

Involvement of human CRM1 (exportin 1) in the export and multimerization of the Rex protein of human T-cell leukemia virus type 1

We investigated the role of human CRM1 (hCRM1) (exportin 1) in the function of Rex protein encoded by human T-cell leukemia virus type 1. hCRM1 promoted the export of Rex protein from the nucleus to the cytoplasm. A Rex protein with a mutation in the activation domain, RexM90, lost both the ability to bind to hCRM1 and the ability to multimerize. The overexpression of hCRM1 complemented the functional defects of RexM64, which contains a mutation in the multimerization domain of Rex. A dominant-negative mutant of Rex which sequesters cofactors of Rex abrogated multimerization as well as the activity of the wild-type Rex protein. These two functions were simultaneously restored by the overexpression of hCRM1. Taken together, these results suggest that hCRM1 plays important roles in the multimerization and export of Rex protein.

Detection and delineation of CXCR-4 (fusin) as an entry and fusion cofactor for T-tropic [correction of T cell-tropic] HIV-1 by three different monoclonal antibodies

A chemokine receptor, CXCR-4, has been identified as an entry cofactor for T cell line-tropic (T-tropic) HIV-1. To detect expression of CXCR-4 at the single cell level and dissect postbinding events of HIV-1 infection, we generated three mAbs against human CXCR-4. These mAbs inhibited SDF-1-induced intracellular Ca2+ mobilization, and one of the mAbs immunoprecipitated a specific 47-kDa component from CXCR-4+ cells. Flow cytometric analysis showed that most human cell lines examined expressed CXCR-4. A fraction of normal PBMC expressed CXCR-4, but neutrophils were negative. Two-color analysis revealed that the majority of T cells, virtually all B cells, and all monocytes expressed CXCR-4, while it was only weakly present on NK cells. Thus, expression of CXCR-4 is not ubiquitous but cell type specific in hemopoietic cells. The three mAbs were shown to suppress cell fusion mediated by envelope proteins of a T-tropic NL432 virus but not by those of an M-tropic JRCSF virus Likewise, they suppressed infection of NL432 but not that of an M-tropic NL162 virus. In both cases it was noted that the suppressive activity varied considerably among the mAbs. These data confirmed that CXCR-4 is directly involved in env-mediated entry and fusion of T-tropic HIV-1 and suggest that the epitopes on CXCR-4 recognized by the three mAbs may have different roles in interaction with the envelope proteins of T-tropic HIV-1.

Functional expression of human mannan-binding proteins (MBPs) in human hepatoma cell lines infected by recombinant vaccinia virus: post-translational modification, molecular assembly, and differentiation of serum and liver MBP

Human mannan-binding proteins (MBPs) occur in two forms, serum MBP (S-MBP) and liver MBP (L-MBP), both of which are synthesized in the liver from a single form of human MBP mRNA. To investigate further the mechanisms of post-translational modification, molecular assembly and differentiation of S-MBP and L-MBP in vitro, we expressed a full-length human MBP cDNA in three human hepatoma cell lines, using the vaccinia virus expression system. The expression of human MBP cDNA reproduced the native MBP differentiation of S-MBP and L-MBP in human hepatoma cells. The recombinant S-MBP was secreted into the medium, and the recombinant L-MBP retained in the cells. The former had the ability to activate the complement through the classical or lectin pathway but the latter did not. Furthermore, one notable difference between the two MBPs was the degree of oligomerization through interchain disulfide bonds between subunits. In addition, we showed that both S-MBP and L-MBP undergo hydroxylation of lysine and proline residues in collagen-like sequences, and that the hydroxylysine is glycosylated to form glucosylgalactosylhydroxylysine (GluGalHyl) and galactosylhydroxylysine (GalHyl). Hydroxylation was required for S-MBP to be assembled into large complexes, the apparent molecular sizes of which were estimated to be 200-1,300 kDa by SDS-PAGE under non-reducing conditions and gel filtration under non-denaturing conditions. The hydroxylation and subsequent glycosylation and oligomerization were inhibited by alpha,alpha'-dipyridyl, an inhibitor of collagen lysyl and prolyl hydroxylases. These results suggested that newly synthesized lectins undergo post-translational modifications unique to the two forms of MBP, S-MBP, and L-MBP, in human hepatocytes and hepatoma cells, and that the collagen-like domains of the MBPs play an important role in promoting molecular assembly.

CXCR4/fusin is not a species-specific barrier in murine cells for HIV-1 entry

Since some murine cells expressing human CD4 fail to internalize HIV-1, another block was thought to be located at the level of viral entry in addition to CD4. Recently, CXCR4 was shown to function as a coreceptor for T cell line-tropic HIV-1 entry. Here we demonstrated that cells expressing murine CXCR4 and human CD4 fused with cells expressing the env proteins derived from T cell line-tropic HIV-1 and were infected with T cell line-tropic HIV-1 strains. In contrast, the same cells were not infected with chimeric clones constructed by substitution of monocyte- or macrophage-tropic strain-derived env region or V3 region into T cell line-tropic HIV-1, indicating V3 loop of envelope protein is required for murine CXCR4mediated HIV-1 entry. We conclude that murine CXCR4 is not a species specific barrier to the entry of T cell line-tropic HIV-1.

Two distinct pathways for intronless mRNA expression: one related, the other unrelated to human immunodeficiency virus Rev and human T cell leukemia virus type I Rex functions

Intronless mRNAs were classified into two classes based on the sensitivities of their expression to the inhibitory effect of TAgRex, a dominant-negative mutant of the Rex protein of human T cell leukemia virus type I, and their abilities to express the genes encoded in the intron of the human immunodeficiency virus (HIV) genome. Interferon-alpha mRNA could not induce the expression of the env gene of HIV, and its expression was resistant to TAgRex. In contrast, the posttranscriptional regulatory element (PRE), necessary for the nucleo-cytoplasmic export of mRNAs of hepatitis B virus, induced expression of the chloramphenicol acetyl transferase gene located within the intron of the HIV genome. PRE-mediated expression was inhibited by TAgRex. Thus, these results suggest that there are at least two distinct pathways for intronless mRNA expression, one related to and the other unrelated to Rev and Rex functions.

Long-term persistence of protective immunity in cynomolgus monkeys immunized with a recombinant vaccinia virus expressing the human T cell leukaemia virus type I envelope gene

To develop effective vaccines against infection with human T cell leukaemia virus type I (HTLV-I), we constructed a recombinant vaccinia virus (WR-SFB5env) synthesizing the HTLV-I envelope (Env) gp46 protein under the control of a strong promoter, termed the ATI hybrid promoter. WR-SFB5env expressed a large quantity of gp46. In cynomolgus monkeys (Macaca fascicularis) immunized with WR-SFB5env, anti-HTLV-I Env antibody, including neutralizing antibody, was induced and remained at a high level until 136 weeks (2-6 years) post-infection (p.i.). These immunized monkeys had HTLV-I Env-specific cytotoxic T lymphocyte activity. At 136 weeks p.i., the immunized monkeys were challenged with an HTLV-I-producing cynomolgus T lymphocyte cell line. Neither HTLV-I antigen nor HTLV-I proviruses were detected in peripheral blood mononuclear cells, lymph nodes or spleens of the WR-SFB5env-immunized monkeys, in contrast to non-immunized control monkeys. These results indicate that a single immunization with WR-SFB5env induced prolonged humoral and cellular immune responses to HTLV-I and protected the monkeys against virus challenge.

Identification of HTLV-1-specific CTL directed against synthetic and naturally processed peptides in HLA-B*3501 transgenic mice

Previous studies of CTL responses to influenza peptides in HLA single transgenic mice resulted in the identification of at most one immunodominant epitope. Since HLA-B*3501 is known to present multiple HIV-1-specific T cell epitopes we tested the cellular immune response of HLA-B*3501 transgenic mice to synthetic HTLV-1 peptides mixed with the lipohexapeptide N-palmitoyl-S-[2,3-bis(palmitoyloxy)propyl]cysteinyl-seryl-lysyl-l ysyl- lysyl-lysine, which is a biocompatible, Th-epitopeindependent adjuvant. Eleven of 37 tested HLA-B*3501 binding peptides mounted a CTL response after three in vitro stimulations. The HLA-B*3501 affinity of peptides correlated with their ability to induce CTL in HLA-B*3501 transgenic mice. Seven peptides derived from env-gp46 (VPSPSSTPLL, VPSSSSTPL, YPSLALAPH, and YPSLALAPA), pol (QAFPQCTIL), gagp19 (YPGRVNEIL), and tax (GAFLTNVPY) proteins induced peptide-specific CTL Bulk CTL generated by four peptides derived from env-gp46 (SPPSTPLLY, VPSPSSTPLLY, and VPSPSSTPLL) and pol (QAFPQCTILQY) killed peptide-pulsed and recombinant vaccinia-infected target cells. The latter peptides therefore present T-cell epitopes and are vaccine candidates for our transgenic mouse model.

Asymptomatic colorectal cancer detected by screening

PURPOSE

Colorectal cancer screening has become prevalent. To discuss the efficacy of screening, we studied the characteristic of asymptomatic colorectal cancer detected by screening.

METHODS

This is a retrospective review of patients with colorectal cancer treated at our institution. During the past 20 years, 96 of 1,046 cases of colorectal cancer were asymptomatic and detected by screening. Sixty-one of these cases were detected in the recent five years. The initial screening procedures were fecal occult blood test in 51 cases, sigmoidoscopy or colonoscopy in 18, barium enema in 9, and other tests in 18.

RESULTS

Thirteen lesions (14 percent) were smaller than 1.0 cm and 32 (33 percent) were 1-2 cm in size. There were 34 Tis, 21 T1, and 8 T2 tumors. Of the 55 Tis or T1 lesions, 14 showed nonpolypoid growth (5 flat-elevated, 7 flat-elevated with depression, 1 flat, 1 depressed), and 12 of these were detected on endoscopy. Thirty-four cases were TNM Stage 0, 25 were Stage I, 16 were Stage II, 12 were Stage III, and 9 were Stage IV. Sixty-one percent of those detected by screening were in either Stage 0 or Stage I compared with 16 percent in the symptomatic group. Cumulative five-year disease-free survival rates were 100 percent for both Stage 0 and Stage I, 94 percent for Stage II, and 52 percent for Stage III. Overall cumulative five-year survival rate was 87 percent for those detected by screening, compared with 57 percent in symptomatic patients.

CONCLUSIONS

Asymptomatic cancers detected by screening were at a less advanced stage. In particular, many nonpolypoid early cancers were detected by endoscopic screening.

Radiologic and pathologic characteristics of mixed dust pneumoconiosis

Modern radiologic technology has to led to increased diagnostic efficacy and accuracy in demonstrating pulmonary changes secondary to occupational dust exposure. This article presents three cases of typical and two cases of atypical silicosis with rounded atelectasis as seen in computed radiographic (CR), computed tomographic (CT), and scintigraphic images and autopsied lung specimens. Chest radiographs revealed both small rounded and small irregular opacities. Small irregular opacities on chest radiographs often proved to be reticular or honeycomb patterns on CT scans. Irregular opacities seen on CR and CT images represented interstitial fibrotic or mixed dust fibrotic changes associated with the accumulation of birefringent particles and emphysematous change, as noted at histologic analysis. CT scans and scintigrams were useful for visualizing parenchymal abnormalities, especially fibrotic change, emphysematous change, and pleural abnormalities.

Effects of translation initiation factor eIF-5A on the functioning of human T-cell leukemia virus type I Rex and human immunodeficiency virus Rev inhibited trans dominantly by a Rex mutant deficient in RNA binding

The viral transactivator proteins Rex and Rev are necessary for the expression of structural proteins of human T-cell leukemia virus type I and human immunodeficiency virus type 1, respectively. Although the interaction of Rex/Rev with a cellular cofactor(s) has been thought to be required for Rex/Rev action, there is no suitable system to search for the cofactor(s) in mammalian cells. We found that a Rex mutant, TAgRex, which contains a simian virus 40 nuclear localization signal in place of the N-terminal 19 amino acids of Rex, could dominantly inhibit wild-type Rex/Rev functions. The inhibition did not require either Rev response element/Rex response element binding or the oligomerization ability of the mutant, but it did require a region around amino acid 90 of the Rex protein, suggesting that TAgRex sequestered the cellular cofactor. Complementation with the eukaryotic translation initiation factor 5A (eIF-5A) in this system could restore the impaired Rex function. These results indicate that eIF-5A is the cofactor indispensable for Rex function. Additionally, by using a two-hybrid system, the homo-oligomer formation of Rex was found to be mediated by the region around amino acid 90 in addition to Tyr-64 and Trp-65 of Rex protein. Thus, eIF-5A may play a part in the formation of the Rex homo-oligomer.

[A case of multiple liver metastasis from remnant gastric cancer responding to leucovorin.5-FU+UFT therapy]

We report a case of a 67-year-old male patient who experienced multiple liver metastasis 6 months after undergoing an operation for remnant gastric cancer. The histological classification of the cancer in gastric remnant was poorly-differentiated adenocarcinoma. The patient was treated with a low dose of LV.5-FU once a week and oral UFT as an outpatient. As a result, after 3 months of the treatment, CT showed that multiple liver lesions almost disappeared, a condition that lasted about 3 years without relapse. Toxic effects due to this treatment were temporary slight liver disfunction, mild anorexia and stomatitis. This case indicates that the regimen of LV.5-FU+UFT may be effective for multiple liver metastasis from postoperative remnant gastric cancer, enabling the patient to maintain an excellent QOL (quality of life).

Vaccination of rabbits with recombinant vaccinia virus carrying the envelope gene of human T-cell lymphotropic virus type I

Two groups of 3 rabbits each were immunized with either recombinant vaccinia virus, WR-SFB5env, carrying the human T-cell lymphotropic virus type I (HTLV-I) env gene at the site of the hemagglutinin gene of the WR strain, or control vaccinia virus, HA-WR, lacking the functional hemagglutinin gene. All 6 rabbits responded with anti-vaccinia virus antibodies. WR-SFB5env elicited anti-HTLV-I env antibodies but no vesicular stomatitis virus (HTLV-I) pseudotype neutralizing antibodies in all 3 rabbits. After 10 weeks, the animals were challenged by transfusion of blood from an HTLV-I-infected rabbit. Two of the 3 vaccinated rabbits and all 3 control rabbits became infected with HTLV-I, as indicated by seroconversion and detection of HTLV-I proviral sequences by polymerase chain reaction. The rabbit that had been protected from initial challenge became infected with HTLV-I upon rechallenge 12 weeks after the first challenge. In view of the proven prophylactic effect of passive immunization against HTLV-I, our vaccine trial failed because WR-SFB5env was incapable of inducing neutralizing antibodies against HTLV-I in the immunized animals. It remains to be studied whether cell-mediated immunity such as antibody-dependent cellular cytotoxicity was involved in the temporary protection of I vaccinated rabbit.

[Continuous intraarterial infusion of 5-fluorouracil plus leucovorin for liver metastases from colorectal cancer]

Between September 1990 and August 1994, 11 patients (pts) with liver metastases (mets) from colorectal cancer were treated with continuous hepatic arterial infusion chemotherapy of 5-fluorouracil (FU) plus leucovorin (LV). Eight pts had non-resectable liver mets (H3: 7, H2: 1), and 3 had residual small mets after resection of major mets. Drugs were administered via an extracorporeal infusion device connected to the hepatic arterial infusion port. 5-FU and LV were given through a 5- to 7-day continuous infusion at 500-750 mg/body/day and 30 mg/body/day, respectively, with a 3- to 4-week rest period. In the recent 6 pts, cisplatin was administered as a 2-hour infusion at 25 mg/body, one or two times simultaneously. Grade 2 toxicity was noted in two pts (18%). One was stomatitis and another was uncontrolled ascites in an advanced cirrhotic pt. The response rate in the 9 evaluable pts was 67% with 6 PR and no CR. The duration of the response was 5 to 9 months. One- and two-year survival rates were 75% and 22%, respectively. These results were superior to those of the intermittent bolus injection of 5-FU plus MMC (or epirubicin) in 40 pts from 1977 to 1994. These results suggest that continuous 5-FU plus LV arterial infusion is an effective regimen in pts with liver metastases from colorectal cancer. However, the infusion with an extracorporeal device limits the pts' quality of life. Further investigation is needed for a schedule that can be practiced for a longer period.

In vitro induction of cytotoxic T lymphocytes against HTLV-I-infected T-cells from adult T-cell leukemia patients, asymptomatic HTLV-I carriers and seronegative healthy donors

We investigated an in vitro method to produce cytotoxic T lymphocytes (CTLs) against HTLV-I-infected T-cells using peripheral blood mononuclear cells (PBMC) of adult T-cell leukemia (ATL) patients, asymptomatic HTLV-I carriers (AC) and seronegative healthy donors. The PBMC were restimulated repeatedly for 4 weeks with HLA-matched HTLV-I-infected T-cells which had been pretreated at 56 degrees C for 30 min to inactivate infectious HTLV-I. The culture medium included 10-100 units/ml of recombinant lymphokines (rIL-1, rIL-2, rIL-4, rIL-6 and rIL-7) and 10% fetal calf serum in RPMI-1640 medium. The cytotoxic activity was measured against HLA-matched HTLV-I-infected T-cell lines after CD4+ or CD8+ cells were positively panned from the cultured PBMC. The PBMC of ATL, AC and healthy donors were able to produce either CD4+ or CD8+ CTLs against HTLV-I-related antigens (env, gag, p21x, p27rex and p40tax) as well as the antigen(s) of as-yet unknown specificity expressed on HTLV-I-infected T-cells. All the CTLs recognized the specific antigens in the context of either class I or class II HLA types. These results indicated that ATL patients, AC and healthy donors were immunocompetent to generate CTLs against HTLV-I-infected T-cells and probably against HTLV-I-transformed T-cells.

A cellular protein which is coprecipitated with HTLV-I rex protein in the presence of the target mRNA

We examined the cellular protein(s) which can associate with Rex protein of human T cell leukemia virus type I (HTLV-I), using Rex-maltose binding protein (MBP) fusion protein. Immunoprecipitation of RexMBP with anti-MBP antibody revealed that a 24 kD protein (p24) associated with RexMBP only in the presence of Rex-responsive mRNA. The fact that p24 was present in both the nucleus and the cytoplasm is consistent with a role of Rex in the nucleo-cytoplasmic transport of viral mRNAs. P24 did not interact with nonfunctional Rex mutant proteins even if they had RNA binding activity in vitro. These results suggest the possible involvement of p24 in the Rex function through a complex formation with Rex on Rex-responsive mRNA.

Clonal expansion of CD8+ cytotoxic T lymphocytes against human T cell lymphotropic virus type I (HTLV-I) genome products in HTLV-I-associated myelopathy/tropical spastic paraparesis patients

Short-term culture of peripheral blood mononuclear cells (PBMC) derived from patients with human T cell lymphotropic virus type I-associated myelopathy (HAM)/tropical spastic paraparesis resulted in dominance by DR+ activated CD8+ T cells. Variations in the T cell receptor (TCR) V alpha and V beta chains in these cells were analyzed, and in all 10 patients examined, 2-3 V gene families were dominant in both TCR V alpha and V beta. In five patients we examined, cultured lymphocytes contained cytotoxic lymphocytes for p40tax (patients HAM2, 3, 7, and 8) or env protein (patient HAM4) of human T lymphotropic virus type I. In patients HAM2 and HAM8, cultured lymphocytes contained a large proportion of V beta 8+ CD8+ and/or V beta 12+ CD8+ cells. The sequence of V beta 8+ and V beta 12+ cDNA revealed that they were oligoclonal with identical or similar sequences in each patient. Elimination experiments with monoclonal antibodies for TCR V beta 8 and V beta 12 showed that they were CD8+ cytotoxic T lymphocytes (CTL) for p40tax. In addition, flow cytometry and sequencing analysis of uncultured PBMC revealed that in HAM2, V beta 8+ CTL and their precursors account for 7% and V beta 12+ CTL and their precursors account for 18% of total CD8+ cells. This indicates the presence of two markedly expanded clones in vivo. No common dominant TCR V alpha or V beta were observed among 10 HAM patients analyzed.

Induction of antibody responses that neutralize human T-cell leukemia virus type I infection in vitro and in vivo by peptide immunization

In order to define neutralization regions on the envelope antigen of human T-cell leukemia virus type I (HTLV-I), we have generated a number of new anti-envelope gp46 monoclonal antibodies from rats and mice. Epitopes recognized by new monoclonal antibodies which could neutralize HTLV-I in syncytium and transformation inhibition assays were localized to sequences in gp46 from amino acids 186 to 193, 190 to 195, 191 to 195, 191 to 196, and 194 to 199. Ovalbumin-conjugated synthetic gp46 peptides containing these neutralization epitopes, pep190-199 (a synthetic gp46 peptide containing amino acids 190 to 199) and pep180-204, but not pep185-194 or pep194-203, could give rise to HTLV-I-neutralizing antibody responses in rabbits. These immune or nonimmune rabbits were then challenged with HTLV-I by intravenous inoculation with 5 x 10(7) live HTLV-I-producing ILT-8M2 cells. By a PCR assay, it was revealed that HTLV-I provirus was detected in peripheral blood lymphocytes from nonimmune and pep288-312-immunized rabbits, whereas the provirus was not detected in peripheral blood lymphocytes from pep190-199- and pep180-204-immunized rabbits over an extended period. These results suggest that the induction of anti-gp46 neutralizing antibody responses by immunization with synthetic peptides has the potential to protect animals against HTLV-I infection in vivo.

Constructions of vaccinia virus A-type inclusion body protein, tandemly repeated mutant 7.5 kDa protein, and hemagglutinin gene promoters support high levels of expression

We devised vaccinia virus (VV)-based vector systems that support higher levels of expression of cloned genes in the early and late phases of the infection cycle than reported previously. Enhanced expression can be obtained by combining the promoter of the A-type inclusion body protein gene, the mutated early region of the 7.5-kDa gene promoter (7.5-kDa promoter), and the promoter of the hemagglutinin (HA) gene. One construct produced 60 micrograms/10(6) cells of chloramphenicol acetyltransferase (CAT), equivalent to 10-18% of total cell protein. Another construct produced about seven times more CAT during the early phase than the amount synthesized under the control of the 7.5-kDa promoter alone. The envelope proteins of human immunodeficiency virus type I synthesized during the early phase of infection were more active as immunogens than these proteins synthesized during the late phase, regardless of the amounts produced.

Demonstration of desmosomal antigens by electron microscopy using cryofixed and cryosubstituted skin with silver-enhanced gold probe

In a previous post-embedding immunogold electron microscopic (EM) studies, localization of various desmosomal antigens was possible at high but not at low magnification. We developed a method for simultaneous demonstration of epidermal desmosomal antigens at both low- and high-power EM magnifications by a method based on cryofixation and acetone cryosubstitution and the use of a 1-nm gold probe with silver enhancement. Ultra-thin sections of Lowicryl K11M were incubated with primary antibodies against desmoplakin, desmocollin, or desmoglein, followed by 1-nm gold-conjugated secondary antibody. Silver enhancement for 12 min provided the ideal labeling size for low-power visualization, whereas silver enhancement for 4-6 min was ideal for high-power EM observation. Each desmosome immunolabeled with the gold probe was clearly demonstrated, even at very low-power magnification. The level of background labeling could be determined easily and the area of interest for high-power observation selected accurately. The fine ultrastructural appearance of desmosomal molecules was precisely demonstrated on high-power observation. This system should be useful for the immunocytochemical study of a variety of desmosomal antigens as well as other molecules of interest.

Cytotoxic T cell response and expression of the target antigen in HTLV-I infection

The cytotoxic T cell response of peripheral blood mononuclear cells (PBMC) to in vitro stimulation with human T cell leukemia virus type I (HTLV-I) was compared among HTLV-I-infected individuals with various clinical conditions. Induction of HTLV-I-specific cytotoxic T lymphocytes (CTL) was observed in 57% of asymptomatic HTLV-I carriers, 86% of patients with HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) or other HTLV-I-related inflammatory diseases, and 18% of adult T cell leukemia (ATL) patients. HTLV-I p40tax, one of the major CTL target antigens, has an epitope strongly associated with HLA-A2. HTLV-I p40tax-specific CTL were frequently induced from HLA-A2-positive donors with HTLV-I-related inflammatory diseases regardless of neurological symptoms, but not from all the HLA-A2-positive HTLV-I-infected individuals tested. Leukemic cells of an ATL patient with HLA-A2, whose PBMC did not show an HTLV-I-specific CTL response, could be lyzed by p40tax-specific CTL derived from an HAM/TSP patient. This indicates that i) the presence of a certain HLA presenting CTL epitopes is not the sole determinant of the individual CTL response to HTLV-I, ii) HTLV-I-specific CTL act as potential effectors of anti-tumor surveillance in vivo. The role of HTLV-I-specific CTL, however, may be limited by another in vivo mechanism suppressing the expression of HTLV-I antigens. This suppression, presumably mediated by a plasma factor and commonly observed in HTLV-I-infected individuals, could be one reason for the persistence of HTLV-I-infection.

Stress-induced expression of the c-fos proto-oncogene in the hippocampal formation

To investigate the effects of stress on c-fos mRNA expression, rats were submitted to forced immobilization for 15, 30, 60 or 120 min before sacrifice. In situ hybridization was performed on sections containing the dorsal hippocampus with a 32P-labelled 50-base oligonucleotide probe (10(7)-10(9) cpm/micrograms) complementary to nucleotides 370-319 of rat c-fos. Forced restraint induced a time-dependent increase in c-fos mRNA expression which was most pronounced in the dentate gyrus and CA1-CA3 regions of the hippocampal formation, and which peaked after 30 min of immobilization (72.7 +/- 1.0 vs 24.1 +/- 0.8 cpm/mm2 in unrestrained animals). A positive but weaker signal was also detected in the amygdala, pyriform cortex and other parts of the cerebral cortex and habenulae. These results suggest that the hippocampal formation is activated during stress.

[5-Fluorouracil plus low-dose leucovorin in the treatment of advanced colorectal cancer]

From September 1989 to September 1992, 17 patients (pts) with non-curative or recurrent colorectal cancer were treated with 5-fluorouracil (FU) plus leucovorin (LV) systemic therapy. The sites of evaluable metastases were liver (10), peritoneum (4), lung (3) and others (6). The LV dosage was 30 mg/body (low-dose method) and the FU dosage was 500-750 mg/body. Both drugs were administered either 5 days/every 4 weeks or one day/every 1 to 2 weeks via protracted or bolus infusion. The regimen was generally well tolerated, although 9 pts (53%) experienced toxicity which required dose reductions. Overall response rate was 29% (5 PR). No CR was observed. Improvement in tumor-related symptoms was noted temporarily in 7 out of 10 pts. Serum CEA level decreased in 13 out of 14 pts. All the response sites were liver (5), with simultaneous lung (1) or peritoneum (1) metastasis. The response duration was 3 to 10 months (mean 6.2 months). Second-line therapy after progression of diseases, such as combination with CDDP, was attempted in some of the PR pts, but no re-response was observed. We conclude that FU plus low-dose LV regimen is an effective therapy for advanced colorectal cancer, but further attempts should be made to increase response rate, prolongation of response duration and effective second-line therapy after progression.