Analysis of SIDS-related civil and criminal court cases in Japan

Thirty-three sudden infant death syndrome (SIDS)-related civil and criminal lawsuits in Japan were retrieved from judicial precedent databases "Hanrei Masutar (Judicial Decisions Master)" and "Hanrei Taikei (Judicial Decisions System) using "SIDS" as a keyword. Sleeping posture and developmental stage of occurrence were studied in each of the cases retrieved, whether or not a legal autopsy had been performed. The influence exerted on court decisions by Japanese definitions of SIDS as well as the relationship between causes of death and court decisions were studied. Of 33, two were criminal cases (business/professional negligence on the part of the defendants, leading to death), and the rest were civil cases (claims for damages). Because the decision handed down in both criminal cases was "cause of death unknown", these defendants were found innocent. One of these cases was argued in both the court of appeals and the superior court: these courts found SIDS to be the cause of death and consequently the claim for damages was rejected. Both criminal and civil courts dealt with another case: the former found the cause of death to be "unknown" and the defendant innocent, while the latter, finding SIDS the cause of death, declined to review. In cases where the sleeping posture was prone, courts tended to decide the cause of death to be suffocation, especially with neonates. Because diagnosis by exclusion is required in cases of a legal autopsy for SIDS, the diagnosis is difficult without an autopsy. Disagreements between the results of legal autopsy and court decisions occurred in eight cases. With such a discrepancy, a detailed case examination is necessary. In 1983, SIDS was defined in Japan in two different ways; one in a more strict sense and the other being more inclusive. The wider and narrower definitions were unified in 1995 by requiring a survey of the circumstances of death in addition to the narrower definition. Because of this situation, the two cases in the 1980s when legal autopsy was not enforced fell into the category of "SIDS in a wider sense." In no case was a defendant found guilty when the cause of death was judged to be either SIDS/ALTE or unknown. Four cases were rejected when the cause of death was judged to be neither due to suffocation nor SIDS, while seven were accepted either as cases of "joint faults that canceled each other," or as "partial acceptance." In Japan, official views concerning a SIDS diagnosis differ among pediatricians, legal scholars of forensic medicine and pathologists. These differences appeared to influence the legal decisions. Several conferences should be convened as soon as possible to provide an opportunity to resolve the main points of difference between these three professional groups and, thus, attain a unified view.

Molecular biology in cerebral cortex of sudden infant death syndrome

Full-scale investigations of sudden infant death syndrome (SIDS) by methods of molecular pathology have been carried out. This paper reports the basic preliminary data of SIDS cerebral cortex analyzed by restriction landmark genomic scanning (RLGS) method, which is the second dimension electrophoresis of DNA recently developed in Japan. The RLGS method was carried out separately using the cerebral cortex of a 4-month-old infant with SIDS and using the cerebral cortex of a 3-month-old infant as a control to investigate SIDS-specific spots. As a result, the coincidence rate of spots between the infant with SIDS and the infant without SIDS was 98.12%. The average coincidence rate of spots in humans is usually 99.07%. Therefore, it was confirmed that the coincidence rate of spots by RLGS between the infant with SIDS and the infant without SIDS was lower than that in humans. In addition, the incidence of SIDS-specific spots was 1.19% and the incidence of non-SIDS-specific spots was 0.6%.

Research for improving the autopsy rate for infant death--medical economic assessment of the forensic autopsy system in Japan

The rate at which autopsies are performed in Japan for cases of infant death is not adequate for diagnosing sudden infant death syndrome (SIDS). In Japan, it will be necessary to increase the autopsy rate at the time of infant deaths in order to improve the certainty of diagnosing SIDS and improving the accuracy of determining the cause of death with respect to infant death. The objective of this research is to provide basic documentation required for administrative implementation of this objective. In Japan, the Medical Examiner System and its related Approved Autopsy System are not deployed nationwide. The estimated budget in the case of deploying the Medical Examiner System nationwide for the purpose of improving the infant death autopsy rate is in excess of 5 trillion yen, and that in the case of deploying the Approved Autopsy System nationwide is estimated at roughly 130 million US dollars. However, since the rate of autopsies performed for SIDS has not changed following the implementation of approved autopsies, the efficacy of the Approved Autopsy System has come to be viewed questionably. In addition, it is also necessary to enact legislation that mandates the conducting of autopsies for all cases of infant death as is done in Scandinavia. The required cost in the case of performing autopsies for all cases of abnormal infant death is estimated at 200,000-700,000 US dollars and is considered to be within a range that could be implemented through local government regulations. In addition, the cost per body of an autopsy performed at the State Crime Laboratory in the State of Arkansas in the US in 1999 was about 6000 US dollars. In contrast, the same cost at the Tokyo Medical Examiner Office is much less at only about 4000 US dollars.

Study on social responses (encouraging public awareness) to sudden infant death syndrome: evaluation of SIDS prevention campaigns

The sudden infant death syndrome (SIDS) prevention campaign promulgated by the SIDS Family Associations was initiated and directed to medical professionals in 1996 and to mothers in 1997. In mid-1998, the Ministry of Health and Welfare began to support this campaign. In parallel with these moves and with cooperation from the study group of the Ministry of Health and Welfare and the SIDS Family Associations of Japan, a Japanese segment of the International Child Care Practices Survey (ICCPS) was conducted in two phases--from 1996 to 1997 and from 1998 to 1999--to observe the trends in risk factors for SIDS that may exist in the child rearing environment in Japan. Consequently, after the SIDS prevention campaign, the risk factors for SIDS, such as the practice of placing infants in a prone posture, smoking, and formula feeding, were reduced. Correspondingly, it was shown that the incidence of SIDS in Japan and in Kanagawa Prefecture where the survey was carried out considerably decreased (0.42-0.24 per 1000 live births). These data indicate that this prevention campaign has been effective.

Comparison between SIDS-related court cases in the United States and Japan--a trend seen in legal precedents in the United States

A bibliographic search of "Lexis", a database on foreign legal cases, was conducted, using sudden infant death syndrome (SIDS) as a key word to retrieve legal cases related to SIDS in the United States. The procedure yielded 156 cases, which included many that were brought to the courts for reasons other than SIDS. The following explanation was given for this outcome: because the public in the United States is much better informed about SIDS than in Japan, few cases are brought to the courts with SIDS as the main cause of the argument; the acronym, SIDS, is simply quoted during the court proceedings. Nevertheless, 26 cases that were particularly related to SIDS were selected and compared against 33 cases recorded and retrieved in the previous year in Japan to find the difference in the trends in legal disputes. The difference in the trends in litigation in the two countries was evident: in most cases in Japan, the legal dispute was over the recognition of SIDS or asphyxiation as the cause of death that had occurred in a nursery or hospital, with the family acting as the plaintiff and the nursery or hospital as the defendant. In the majority of cases in the United States, on the other hand, the state was the plaintiff and the family or baby sitter the defendant; the focal point of the dispute was the distinction between SIDS and child abuse. Compared with the trend in Japan, a much greater number of cases were brought before the court of final appeals in the United States. As the public becomes more aware of SIDS through campaigns and other means, the pattern seen in the legal disputes refer to SIDS lawsuits in Japan may change into that seen in the United States.

Study to increase the frequency of autopsies performed for cases of infant deaths--proposed revision of the law on postmortem examination and corpse preservation and other related regulations

By definition, sudden infant death syndrome (SIDS) requires diagnosis through exclusion by conducting an autopsy. To obtain a reliable diagnosis of this disease, an autopsy is essential. However, the frequency with which autopsies are conducted in Japan is not sufficient to meet the need associated with the diagnosis of SIDS. To improve this frequency, various public policies, such as nationwide implementation of the administrative autopsy system (medical examiner system), the application of the practice of autopsy approved by families, and legally required autopsies, are being considered; but none has been put into practice. On the other hand, attention has been called to the fact that the Law on postmortem examination and corpse preservation, which was instituted at the end of the Second World War, requires updating. In the current report, it is proposed that the following be added to Article 8, item 3 of this Law: "the Metropolitan or Prefectural Governor must insist that an autopsy be conducted on all cases of a sudden and unexpected death of an infant to investigate the cause of this death." At present, the annual incidence of SIDS in Japan is reported to be 500. To put the above-recommended legal requirement into practice, the estimated annual addition to the budget, if conducted as approved or an administrative autopsy, will be in the order of 150,000-500,000 dollar, which is within the prescribed limits for an appropriation.

Japanese national SIDS project: 1998-2000 research for the improvement of infant mortality

The aim of the present study is to see if by conducting research on sudden infant death syndrome (SIDS), one of major contributing factors to infant mortality in Japan, infant mortality can be reduced. Concrete approaches taken in this study took four different directions: elucidation of SIDS etiology, prevention, elucidation of its social aspects (education) and the investigation of administrative aspects. At the same time, an attempt was made to get better grasp on the epidemiological trends in infant mortality, including that of SIDS. The idea behind this etiological approach was to unify hitherto separate approaches taken by those in epidemiological, physiological and pathological fields. A molecular-biological approach was also added. Physiologically hypothesized causes of SIDS--apnea and arousal disorder--together with the epidemiologically presumed risk factor of sleeping position, were examined jointly from a pathological viewpoint. Research in the first 2 years of the grant found that hypoxia reflected by gliosis in the brain stem arousal pathway was related to the duration of sleep apnea. Research in the final year of the grant found the possibility of organic fragility in the brain stem arousal pathway, particularly in periaqueducal gray matter and pedunculopontine nucleus reflected by apoptosis and neuronal plasticity. These findings gave support to the arousal disorder hypothesis in SIDS. Application of the restriction landmark genomic scanning (RLGS) method supported the possibility of locating a site for a SIDS-specific gene. The US collaborative home infant monitoring evaluation (CHIME) currently in use was evaluated. In addition, three new monitoring methods were developed: a non-invasive multi-channel pressure-sensing bed, microwave radar, and a pacifier that functions as a suckometer which can be used to evaluate a neonate's autonomic nervous functions. Social (educational) activities included: surveys of the current state of educational campaigns on SIDS in other countries, epidemiological evaluation of campaigns run by the Japan SIDS families' Association to evaluate the effectiveness of the SIDS campaign, and creation of a home page, mostly to inform the public about the output from this research group. "Guidelines for Death Scene Investigation of Sudden, Unexplained Infant Deaths: Recommendations of Interagency Panel on Sudden Infant Death Syndrome" was translated into japanese. Activities that concerned administrative measures included clarification of the unique nature of SIDS-related trials in Japan when compared to those in the United States. Other concrete administrative proposals were: a pressing need to increase the rate of SIDS-related autopsies to facilitate a better etiological understanding and, for this purpose, establishing regulations in local jurisdictions and amending Article 8 of the Postmortem Examination and Corpse Preservation Act, keeping in perspective the medico-economic evaluation of the japanese medical examiner system. For these proposals to be realized, establishment of a new office in charge of administrative and approved autopsies at the national level of government is desirable. Also pointed out were the different opinions held among specialists concerning the diagnosis of SIDS and their need to hold multiple conferences to unify their views. Basic data for these conferences were provided from epidemiological examinations of infant mortality.

Comparative evaluation of diagnostic guidelines for sudden infant death syndrome (SIDS) in Japan

It is a well-recognized fact among professionals that the diagnosis of sudden infant death syndrome (SIDS) involves difficult elements; a SIDS diagnosis is not uniform throughout Japan; and such a diagnosis is not made based on any internationally recognized definition. Faced with this situation, guidelines have been prepared and proposals have been made to standardize and improve the accuracy of SIDS diagnoses, viz. the following three can be cited: "guideline for diagnosis of SIDS" prepared by a Study Group of the Ministry of Health and Welfare; "case studies of SIDS" and a "guideline for its diagnosis" prepared by the Case Study Committee of Japan SIDS Research Society; and a "proposal on the principles of medico-legal pathology concerning SIDS", included in the research report supported by a Grant-in-Aid for Scientific Research from the Ministry of Education. In the current study, a comparison was made focusing on the discrepancies among these three documents. The major discrepancies among these three are: (1) handling of the patient's age (by months or years) in the diagnosis of SIDS; (2) dealing with those cases for which no autopsy has been conducted; (3) attitudes concerning whether sleeping in a prone posture is a cause for asphyxia and (4) opinions concerning the aspiration of vomited milk. It is anticipated that these discrepancies will invite confusion and affect judgments and recognition of SIDS-related cases that will be brought to court. It is essential that those involved with these three documents have an opportunity at the earliest time to discuss the matter and come to a uniform understanding.

Amperometric determination of acetic acid with a trienzyme/poly(dimethylsiloxane)-bilayer-based sensor

A trienzyme sensor for the amperometric determination of acetic acid was prepared by immobilizing acetate kinase (AK), pyruvate kinase (PK), and pyruvate oxidase (PyOx) on a poly(dimethylsiloxane) (PDMS)-coated electrode. AK catalyzes the phospho-transferring reaction between acetic acid and ATP to form ADP; PK, the phospho-transferring reaction between ADP and phosphoenolpyruvate to form pyruvic acid; and PyOx, the oxidation of pyruvic acid with oxygen. The oxygen consumption could be monitored by using the PDMS-coated electrode without interference from the PyOx reaction product, hydrogen peroxide. Thus, the concentration of acetic acid (5 microM-0.5 mM) could be determined from the decrease in the cathodic current at -0.4 V vs Ag/AgCl. This is the first example of a biosensor that can be used for the determination of acetic acid in ethanol-containing food samples. The acetate-sensing electrode could be used for more than one month.

Prefrontal cortical representation of visuospatial working memory in monkeys examined by local inactivation with muscimol

In primates, dorsolateral areas of the prefrontal cortex (PFC) play a major role in visuospatial working memory. To examine the functional organization of the PFC for representing visuospatial working memory, we produced reversible local inactivation, with the local injection of muscimol (5 microg, 1 microl), at various sites (n = 100) in the dorsolateral PFC of monkeys and observed the behavioral consequences in an oculomotor delayed-response task that required memory-guided saccades for locations throughout both visual fields. At 82 sites, the local injection of muscimol induced deficits in memory-guided saccades to a few specific, usually contralateral, target locations that varied with the location of the injection site. Such deficits depended on the delay length, and longer delays were associated with larger deficits in memory-guided saccades. The injection sites and affected spatial locations of the target showed a gross topographical relationship. No deficits appeared for a control task in which the subject was required to make a visually guided saccade to a visible target. These findings suggest that a specific site in the dorsolateral PFC is responsible for the working memory process for a specific visuospatial coordinate to guide goal-directed behavior. Further, memoranda for specific visuospatial coordinates appear to be represented in a topographical memory map within the dorsolateral PFC to represent visuospatial working memory processes.

The effects of dopamine and its antagonists on directional delay-period activity of prefrontal neurons in monkeys during an oculomotor delayed-response task

To examine the role of dopamine receptors in the memory field of neurons for visuospatial working memory in the prefrontal cortex (PFC), dopamine and its antagonists (SCH23390 for the D1-antagonist and sulpiride for the D2-antagonist) were applied iontophoretically to neurons of the dorsolateral PFC in monkeys that performed an oculomotor delayed-response task. In this task, the subject made a memory-guided saccade to a remembered target location that had been cued by a visuospatial stimulus (right, up, left, or down; 15 degrees in eccentricity) prior to a 4-s delay period. We focused here on PFC neurons that showed directional delay-period activity; i.e., an increased activity during the delay period, the magnitude of which varied significantly with the target location. Iontophoretic application of SCH23390 (usually 50 nA) decreased or increased the activities of most of these neurons (n=48/62, 77%); most neurons showed a decrease (n=43/62, 69%). For the neurons affected by SCH23390, a directional index of directional delay-period activity was attenuated by SCH23390, whereas the preferred direction was not greatly affected. The decreasing effect of SCH23390 was dose-dependent; the extent of the decrease was less with a lower dose (20-nA current) than with the ordinary dose (50-nA current), although the effect of the lower dose of SCH23390 on delay-period activity was similar in nature to that of the ordinary dose of SCH23390. Furthermore, the application of dopamine itself augmented directional delay-period activity in most of the neurons tested (n=12/16, 75%). Sulpiride did not have any significant effects in most of the neurons tested (n=15/17). These results suggest that the activation of D1-dopamine receptors play a facilitating role in the memory field of PFC neurons for visuospatial working memory processes.

Characteristics of suicide among children and adolescents in Budapest

BACKGROUND

In Europe, the suicide rate among children and adolescents is the highest in Hungary. In the young age group (10-14 and 15-19 years), the suicide mortality rate had not showed a decrease.

METHODS

This study examined suicide cases committed by children and adolescents highlighted from the extraordinary death cases in Budapest between 1994 and 1998. The 72 suicide cases, which included 59 males and 13 females, were processed by sex, age, method and time of commitment, and distribution by districts.

RESULTS

Leaping off high places or hanging was the highest frequency among the methods of commitment. Accurate data about the frequency, type, time and location of death cases are indispensable to decrease the number of children's and adolescents' suicides.

CONCLUSIONS

Studies of epidemiology and risk factors may provide a basis of development of a specific suicide prevention programme including educational, health and welfare elements.

Comparative analysis of differences by gender in sudden infant death syndrome in Hungary and Japan

We examined the sex ratio in sudden infant death syndrome (SIDS) cases in Hungary, in Tokyo and Japan between 1985 and 1996. From all the infant death cases in Hungary 395 (240 male, 155 female) were SIDS (odds ratio (OR)=1.179, with 95% confidence interval (CI)=0.961, 1.446), in Japan 4348 (2550 male, 1798 female) were SIDS (OR=1.145, with 95% CI=1.076, 1.218) and in Tokyo 307 (178 male, 129 female) were SIDS (OR=1.128, with 95% CI=0.894, 1.423). Male infants showed a significantly higher birth rate than females. The male infants are more vulnerable (p<0.005), however, higher mortality among male infants should not be considered a characteristic feature for SIDS.

International Child Care Practices Study: infant sleeping environment

BACKGROUND

The International Child Care Practices Study (ICCPS) has collected descriptive data from 21 centres in 17 countries. In this report, data are presented on the infant sleeping environment with the main focus being sudden infant death syndrome (SIDS) risk factors (bedsharing and infant using a pillow) and protective factors (infant sharing a room with adult) that are not yet well established in the literature.

METHODS

Using a standardised protocol, parents of infants were surveyed at birth by interview and at 3 months of age mainly by postal questionnaire. Centres were grouped according to geographic location. Also indicated was the level of SIDS awareness in the community, i.e. whether any campaigns or messages to "reduce the risks of SIDS" were available at the time of the survey.

RESULTS

Birth interview data were available for 5488 individual families and 4656 (85%) returned questionnaires at 3 months. Rates of bedsharing varied considerably (2-88%) and it appeared to be more common in the samples with a lower awareness of SIDS, but not necessarily a high SIDS rate. Countries with higher rates of bedsharing appeared to have a greater proportion of infants bedsharing for a longer duration (>5 h). Rates of room sharing varied (58-100%) with some of the lowest rates noted in centres with a higher awareness of SIDS. Rates of pillow use ranged from 4% to 95%.

CONCLUSIONS

It is likely that methods of bedsharing differ cross-culturally, and although further details were sought on different bedsharing practices, it was not possible to build up a composite picture of "typical" bedsharing practices in these different communities. These data highlight interesting patterns in child care in these diverse populations. Although these results should not be used to imply that any particular child care practice either increases or decreases the risk of SIDS, these findings should help to inject caution into the process of developing SIDS prevention campaigns for non-Western cultures.

Unmasking of silent "task-related" neuronal activity in the monkey prefrontal cortex by a GABA(A) antagonist

To examine the role of GABA on prefrontal neuronal activity in the control of behavior, a GABA(A) receptor antagonist, bicuculline methiodite (BMI), was iontophoretically applied to prefrontal neurons while monkeys performed a visual reaction time task. Iontophoretic application of BMI uncovered "task-related" activity of silent neurons (n=40), which did not show any activity during performance of the task. The distribution, by type, of these silent "task-related" neurons differed from that of standard (i.e. active) task-related neurons (N=95), and a particular type of silent "task-related" neuron was found most frequently. These findings suggest that GABA continuously and preferentially suppresses neuronal activity via GABA(A) receptors to limit the population of prefrontal neurons related to behavior, thereby organizing neuronal activities for behavior mediated by the prefrontal cortex.

Parallel visuospatial and audiospatial working memory processes in the monkey dorsolateral prefrontal cortex

The dorsolateral area of the prefrontal cortex (PFC) in primates is involved in visuospatial working memory, but the cellular basis of spatial working memory for auditory information is poorly understood. Here we examined dorsolateral PFC neurons using visual and auditory oculomotor delayed-response tasks. We found that the dorsolateral PFC contains two groups of neurons, each showing directional delay-period activity depending on the location of the visual or auditory cue, suggesting that parallel neuronal processes for visual and auditory spatial working memory occur in the dorsolateral PFC.

The epidemiological study on registered cases of sudden infant death syndrome (SIDS) in Tokyo: examination of the effect of autopsy on diagnosis of SIDS and the mortality statistics in Japan

In the United States and most of European countries, a diagnosis of sudden infant death syndrome (SIDS) may be given only after an autopsy has been performed. Under the new definition of SIDS in Japan, an autopsy is now mandatory for the diagnosis of SIDS. However, according to the official records on autopsies, the proportion of autopsy for sudden infant death in Japan is still low (less than 30%). If a physician suspects SIDS from a review of the patient's medical history and medical findings, he can write 'suspected SIDS' as the cause of death on the death certificate without performing an autopsy. Such a clinical diagnosis is entered in the Vital Statistics section by the Japanese Ministry of Health and Welfare. In this report, a comparative epidemiological survey of registered cases of SIDS--after autopsy and with no autopsy--was carried out by examining the data from the death certificates registered by the Japanese Ministry of Health and Welfare (vital statistics in Tokyo from January 1979 to December 1996). There were 369 cases of SIDS registered in Tokyo. We found 247 diagnosed after autopsy (66.9%) and 122 with no autopsy (33.1%). The following epidemiological variables were used: address of the deceased (a specific area in Tokyo), sex, year of death, time of death, month of death, age at death, occupation of householders, and place of death. There were epidemiological differences at the 0.05 significance level between registered cases diagnosed after autopsy and those diagnosed without autopsies, as follows: year (P=0.016) and place of death (P=0.037). In addition, there were slight epidemiological differences at the 0.10 significance level between registered cases diagnosed after autopsy and with no autopsy, as follows: month of death (P=0.076) and age at death (P=0.082). This suggests that the quality of diagnosis of SIDS is not completely guaranteed. With respect to the area of residence, the incidence of SIDS is high in those areas where autopsy is performed frequently. In Tokyo, the medical examiner system is enforced only in the urban area and there is a possibility that SIDS is being underdiagnosed in the rural area of the Metropolitan Tokyo. It is likely that the diagnosis of SIDS without autopsy will influence the quality of SIDS diagnoses. The administrative inadequacy in the autopsy system in Japan should be corrected to improve the accuracy of SIDS diagnosis.

Post-mortem analysis of apoptotic changes associated with human skin bruises

The estimation of the age of skin bruises is of importance in forensic medicine, especially in child abuse cases. Time-dependent changes in bruise colour and/or associated histological features have been used with a limited degree of success. An increased rate of apoptosis in the injured tissue has been considered as a novel time-dependent marker of cell death, by injury inflicted in a rat model. The object of the present study was to apply the TUNEL method of DNA end labelling to identify and enumerate apoptotic cells in bruised and normal skin in order to study the relationship of apoptotic cell density with the age of the bruise. A commercially available DNA end labelling kit, TUNEL method, was standardised, validated and used for this purpose. Twenty unselected post-mortem cases with bruises due to a variety of causes were studied. The apoptotic cells stained with TUNEL reaction were counted in 10 high power fields in the epidermis, as well as in the dermis of formaldehyde-fixed paraffin-embedded skin specimens. The mean positive cell densities (+/- 1 S.E.) were compared with respect to the age of the bruise. In the epidermis, the mean apoptotic cell count was statistically significantly greater in the bruised skin compared to normal skin in 2- to 6-day-old bruises; whilst in the dermis the same was true in 3- to 8-day-old bruises. The overall findings suggest that there is a quiescent period prior to the increase in the apoptotic cell activity that is seen following skin bruising. This is so provided the post-mortem skin samples were collected within a lapse of 6 days or less between the time of death and formalin fixation and paraffin embedding to avoid the bias made by the difference of length of post-mortem interval.

Application of electrophoresis technology to DNA analysis

We used the variable number tandem repeat (VNTR) polymorphism and the ten short tandem repeat (STR) polymorphisms to study a number of disputed paternity cases in the Japanese population. For the determination of VNTR locus (D1S80) and the ten STR loci (vWA, F13B, TH01, TPOX, CSF1PO, F13A01, LPL, D3S1744, D12S1090, D18S849) we used polymerase chain reaction (PCR) amplification and the vertical polyacrylamide gel electrophoresis technique followed by SYBR green I staining. The irregular repeats were analyzed by sequencing from bands of vertical polyacrylamide gel electrophoresis using the latest gene analyzing equipment, the ABI PRISM 310 Genetic Analyzer. The probable genotypes of the deceased putative father were deduced by Komatu's method from the genotypes of the widow and the genotypes of their children. The calculation of paternity probability used the Essen-Moller formula and Bayes's theorem. Calculated in eleven loci, the distinguishing probabilities (DP) and the mean exclusion chance (MEC) were 0.9999 and 0.9989, respectively. Therefore, information obtained from eleven DNA polymorphisms is enough to determine paternity plausibility.

Properties of delay-period neuronal activity in the monkey dorsolateral prefrontal cortex during a spatial delayed matching-to-sample task

The dorsolateral prefrontal cortex (PFC) has been implicated in visuospatial memory, and its cellular basis has been extensively studied with the delayed-response paradigm in monkeys. However, using this paradigm, it is difficult to dissociate neuronal activities related to visuospatial memory from those related to motor preparation, and few studies have provided evidence for the involvement of PFC neurons in visuospatial memory of a sensory cue, rather than in motor preparation. To extend this finding, we examined neuronal activities in the dorsolateral PFC while a rhesus monkey performed a spatial delayed matching-to-sample (SDMTS) task, which allows us to adequately access visuospatial memory independent of any sensorimotor components. The SDMTS task required the subject to make a lever-holding NOGO response or a lever-releasing GO response when a visuospatial matching cue (white spot, one of four peripheral locations, 15 degrees in eccentricity) matched or did not match a sample cue (physically the same as the matching cue) that had been presented prior to a delay period (3 s). Thus, the SDMTS task requires the subject to remember visuospatial information regarding the sample cue location during the delay period and is suitable for accessing visuospatial memory independent of any sensorimotor components, such as motor preparation, for directed movements. Of a total of 385 task-related neurons, 184 showed a sustained increase in activity during the delay period ("delay-period activity"). Most of these neurons (n = 165/184, 90%) showed positional delay-period activity, i.e., delay-period activity where the magnitude differed significantly with the position of the sample cue. This activity appears to be involved in visuospatial memory and to form a "memory field." To quantitatively examine the properties of positional delay-period activity, we introduced a tuning index (TI) and a discriminative index (DI), which represent the sharpness of tuning and the discriminative ability, respectively, of positional delay-period activity. Both TI and DI varied among neurons with positional delay-period activity and were closely related to the time from the onset of the sample cue to the onset of positional delay-period activity; positional delay-period activity with sharper tuning and a greater discriminative ability had a slower onset. Furthermore, at the population level, both TI and DI were increased during the delay period in the neuronal population with a high DI value. These results extend previous findings to suggest that integrative, convergent processes of neuronal activities for increasing the accuracy of visuospatial memory may occur in the dorsolateral PFC. Thus, a critical role of the dorsolateral PFC in visuospatial memory may be to sharpen it to guide behaviors/decisions requiring accurate visuospatial memory.

hOGG1 Ser326Cys polymorphism and lung cancer susceptibility

The human homologue of the yeast OGG1 gene, hOGG1, has been cloned, and its genetic structure has been determined. Several polymorphisms in the hOGG1 gene were detected in the Japanese populations, and among them, the Ser-Cys polymorphism at codon 326 has been shown to have a functional difference in complementation of mutant Escherichia coli that is defective in the repair of 8-hydroxyguanine. Activity in the repair of 8-hydroxyguanine is greater in hOGG1-Ser326 protein than in hOGG1(326) protein. Because many environmental carcinogens produce 8-hydroxyguanine residue and mismatching to this modified base potentially causes oncogenic mutations, the capacity to repair these lesions can be involved in cancer susceptibility in human beings. We, therefore, examined allele distributions of the Ser326Cys polymorphism in a case-control study of male lung cancer in Okinawa. The analyses based on 241 cases and 197 hospital controls disclosed the following findings. (a) Those with the Cys/Cys genotype were at an increased risk of squamous cell carcinoma and nonadenocarcinoma compared to those with the Ser/Cys and those with the Ser/Ser genotypes combined. The odds ratios adjusted for age and smoking history were 3.01 (95% confidence interval, 1.33-6.83) and 2.18 (95% confidence interval, 1.05-4.54), respectively. (b) The odds ratios for other histological subtypes of lung cancer or those in total were not significant. Those for Cys/Cys or Ser/Cys genotype against Ser/Ser did not reach statistical significance in any cell type. (c) The distributions of this polymorphism varied for different populations (Chinese, Japanese, Micronesians, Melanesians, Hungarians, and Australian Caucasians), with much less prevalence of Cys allele in the latter three populations. Although our sample size was limited, these results indicate that the Ser326Cys variant may be related to squamous cell lung cancer susceptibility. The Cys/Cys genotype appears to be more susceptible to squamous cell carcinoma, although the risk is less than that previously reported to be associated with the CYP1A1 gene. Further studies are needed to assess the importance of the interpopulation variation to cancer susceptibility.

Attenuation of delay-period activity of monkey prefrontal neurons by an alpha2-adrenergic antagonist during an oculomotor delayed-response task

To examine the role of norepinephrine receptors in spatial working memory processes mediated by the prefrontal cortex (PFC), noradrenergic antagonists (yohimbine for alpha2, prazosin for alpha1, and propranolol for beta receptors) were applied iontophoretically to neurons of the dorsolateral PFC in rhesus monkeys that performed an oculomotor delayed-response (ODR) task. The ODR task was initiated when the monkeys fixated on a central spot on a computer monitor and consisted of fixation (1 s), cue (1 of 4 peripheral cues, 0.5 s), delay (fixation cue only, 4 s), and go periods. In the go period, the subject made a memory-guided saccade to the target location that was cued before the delay period. I focused on 49 neurons that showed directional delay-period activity, i.e., a sustained increase in activity during the delay period, the magnitude of which varied significantly with the memorized target location. Iontophoretic (usually 50 nA) application of yohimbine, but not prazosin or propranolol, significantly decreased the activities of most of the neurons with directional delay-period activity (n = 41/49, 81%). Furthermore, yohimbine attenuated the sharpness of tuning, examined by a tuning index, of delay-period activity and had a greater attenuating effect on delay-period activity than on background activity. These findings suggest that the activation of alpha2-adrenergic receptors in the dorsolateral PFC plays a modulatory role in neuronal processes for visuospatial working memory.

Is the incidence of SIDS increasing in Asia?

The incidence of SIDS in western countries has decreased since the late 1980s after active SIDS prevention campaigns. By contrast, both Taiwan and Japan have reported an increase in incidences. In this report data from England, Wales, Scotland, Northern Ireland, Japan and Hong Kong are analysed. Regression coefficient and linearity of regression tests were used to determine if there was any significant increase or decrease in post-neonatal mortality (PNNM), SIDS mortality and mortality among infants 1-5 months old. A statistically significant decrease in SIDS was recognized in England, Wales, Scotland and Northern Ireland, whereas statistically significant increases were noted for Japan and Hong Kong. However in Japan and Hong Kong both the PNNM and mortality of infants between 1-5 months in age fell significantly, suggesting that the increased SIDS rates could be due to a change in diagnostic labelling. Further study will be required to determine whether this increase in the incidence of SIDS is genuine or only an artifact.

[An epidemiological survey of sudden infant death syndrome in Tokyo]

OBJECTIVE

A complete autopsy is essential for an accurate diagnosis of sudden infant death syndrome (SIDS), whereas the autopsy rate is low in Japan. This study investigated the incidence of SIDS in Tokyo, where the autopsy rate for SIDS was the highest in Japan.

METHODS

We selected death certificates of infants aged less than 2 years during 1990 to 1992 in Tokyo, whose cause of death was suspected to be SIDS, and classified those possibilities of SIDS according to death descriptions.

RESULTS

The incidences of SIDS by strict definition and broad definition were 0.23 and 0.32 per 1,000 live births, respectively. Not a few death certificates described causes of death and death scene at some length. If including cases of suspected SIDS, the incidence came to 0.61 per 1,000 live births. The mortality risk of SIDS was significantly higher in infants with male gender and households classified by employment status as "other". Because the medical examiner system functioned only in the central urban area, most SIDS cases were diagnosed at autopsies in the urban area, whereas few cases were autopsied in the surrounding area. Compared to the urban area, the incidence of SIDS was significantly lower in the surrounding areas with low autopsy rates and with many death certificates of ambiguous death description.

CONCLUSIONS

Ambiguous description of the death scene and low autopsy rate may cause under-diagnosis of SIDS. Establishment of a nationwide medicolegal autopsy system and examination of the death scene is necessary to diagnose SIDS accurately.

Monkey prefrontal neuronal activity coding the forthcoming saccade in an oculomotor delayed matching-to-sample task

To determine the role of the dorsolateral prefrontal cortex (PFC) in the selection of memory-guided saccadic eye movements, we recorded the activities of PFC neurons while macaque monkeys performed an oculomotor delayed matching-to-sample task. The task was designed to dissociate motor factors from visual factors in the selection and retention of the direction of the forthcoming saccade during delay periods after the visual cue but before the GO signal was presented. While the monkey fixated on a central fixation spot (FX period, 1 s), a sample cue (1 of 4 geometric figures) and a matching cue composed of two geometric figures were presented in succession (SC and MC periods, respectively, 0.5 s) with a brief delay (D1 period, 1 or 1.5 s). After another delay (D2 period, 1.5 s), the monkey made a saccade (GO period, <0.5 s) toward one of four locations (the goal) that had been indicated by the combination of the sample and matching cues in the MC period. We recorded the activities of 224 neurons in the periprincipal sulcal area of 3 hemispheres of 2 monkeys. Sixty-five neurons (29%) showed a significant increase in activity during the D2 period. Some of these also responded during other phases of the task (SC period, n = 32; D1, 22; MC, 53; GO, 47). Some of the activity during the D2(52/65, 80%) and GO (40/47, 85%) periods was associated with the direction of the forthcoming saccade ("direction selective"). Although most MC-period activities of D2 neurons were direction selective (38/53, 73%), a fraction of them (14/38) was also affected by both saccade direction and matching cue pattern. To compare quantitatively the contribution of motor (saccade direction) and visual (matching-cue pattern) factors to the activity of D2 neurons, we calculated directional and visual dependency indices (DDI and VDI) for each of the three periods (MC, D2, and GO). In both the D2 and GO periods, D2 neurons with high DDI values and low VDI values predominated. In the MC period, however, there was no significant difference between the distributions of DDI and VDI values. These findings suggest that PFC neurons store the direction of memory-guided saccades during a delay period before eye movement and that the same neurons may be involved in the decision-making process that underlies the selection of the saccade direction during the MC period.

Attenuation of preparatory activity for reaching movements by a D1-dopamine antagonist in the monkey premotor cortex

To examine the role of dopamine receptors in the function of the premotor cortex (PM) for preparing for reaching movements, dopamine antagonists (SCH23390 for D1 receptors and sulpiride for D2 receptors) were applied iontophoretically to neurons of the PM of monkeys that performed a delayed-reaching (DR) task with their arms. In the DR task, the monkey made a reaching movement to one of three target levers (left, upper, and right), which had been cued by a visuospatial stimulus before a delay period of 4 s. We focused on neurons (n = 56) that showed a sustained increase in activity during the delay period (delay-period activity; i.e., "set-related" activity), because such activity is considered to play a central role in preparing for forelimb movements. Iontophoretic application of SCH23390 (usually with a current of 50 nA) significantly decreased the activity of most of these neurons (n = 44/56, 79%), and delay-period activity was attenuated during its application. In contrast, application of sulpiride or SCH23388 (an inactive analogue of SCH23390), using the same current intensity, had no effect on most of the neurons tested with these drugs (n = 31/33 and n = 21/23, respectively), despite the fact that their activity was decreased by SCH23390. Furthermore, for neurons that were affected by SCH23390, the percent decrease in delay-period activity was significantly greater than the percent change in background activity. In more than one-half of the neurons (n = 26/44, 59%), background activity was either increased (n = 10) or not affected (n = 16) by SCH23390, even though it significantly attenuated delay-period activity. These findings suggest that the activation of D1-dopamine receptors plays a modulatory role in PM function in preparing for reaching movements.

Chronic infantile neurological cutaneous articular syndrome in a patient from Japan

A case of chronic infantile neurological cutaneous articular (CINCA) syndrome in a Japanese girl, started at the age of 13 days with episodes of fever, rash followed by swollen joint, hepatosplenomegaly, generalized lymphadenopathy and chronic central nervous system involvement, is reported. Some of the findings suggest that this syndrome may be the result of an intrauterine infection. This is the first case of CINCA syndrome in a Japanese girl.

Synaptic interactions between primate precentral cortex neurons revealed by spike-triggered averaging of intracellular membrane potentials in vivo

To document synaptic interactions between neurons in the precentral cortex of macaque monkeys, we recorded in vivo the intracellular (IC) membrane potentials of cortical neurons simultaneously with extracellular (EC) action potentials of neighboring cells. The synaptic potentials correlated with EC spikes were obtained by spike-triggered averages (STA) of the IC membrane potentials for 373 cell pairs recorded in anesthetized and awake behaving monkeys. Sixty-three STAs (17%) showed excitatory postsynaptic potentials (EPSPs), beginning after the trigger spike. Pure EPSPs had onset latencies of 0.9 +/- 0.7 msec (mean +/- SD) and amplitudes of 226 +/- 130 microV. Sixteen STAs (4%) showed postspike inhibitory postsynaptic potentials (IPSPs), with onset latencies of 0.4 +/- 0.4 msec and amplitudes of -274 +/- 188 microV. The most common waveform, observed in 82% of the STAs with features, was a broad depolarization straddling the trigger spikes, reflecting synchronized synaptic input to both IC and EC neurons. These average synchronous excitation potentials (ASEPs) began 14.3 +/- 6.6 msec before the trigger spike and had amplitudes of 1064 +/- 867 microV. Twenty-three STAs (6%) showed an average synchronous inhibitory potential (ASIP): a hyperpolarization beginning before the trigger spike and reflecting IPSPs produced by a group of local inhibitory cells synchronized with the trigger cell. ASIPs had an onset latency of -5.5 +/- 2.7 msec and amplitude of -589 +/- 502 microV. Combinations of synchronous and postspike potentials were also observed. Successive recordings provided examples of convergent and divergent connections between EC and IC cells. Neuron pairs with depolarizing postsynaptic potentials (PSPs) in the STA yielded peaks in the cross-correlograms of the IC and EC action potentials; the peak area was proportional to the amplitude of the PSP. These data suggest that a significantly larger proportion of cortical neurons interact through synchronous activity than through simple serial interactions; moreover, synchronous excitation affected more widely separated cell pairs than EPSPs and IPSPs, which were seen most often among the closest cells.

Analysis of the short tandem repeat systems HUMF13B and HUMvWF in Chinese (Liaoning)

The short tandem repeat (STR) systems HUMF13B and HUMvWF were investigated in 200 healthy Chinese individuals living in Liaoning (The northeast of China). The HUMF13B allele frequencies were 6 = 0.0025, 8 = 0.1825, 9 = 0.1750, 10 = 0.6325 and 11 = 0.0075; and the HUMvWF allele frequencies were 13 = 0.0300, 14 = 0.2475, 15 = 0.0450, 16 = 0.1750, 17 = 0.2600, 18 = 0.1525, 19 = 0.0725 and 20 = 0.0175. The distribution of genotypes corresponded to the Hardy-Weinberg equilibrium. The distinguishing probabilities (D.P) were calculated as 0.7318 and 0.9366; the polymorphism information content (PIC) were calculated as 0.4827 and 0.7822; and the heterozygosity (h) were calculated as 0.5378 and 0.8128, respectively. The HUMF13B and HUMvWF systems provide a useful genetic marker for human genetics, anthropological studies, and forensic science in the chinese population.

Application of the GABA antagonist bicuculline to the premotor cortex reduces the ability to withhold reaching movements by well-trained monkeys in visually guided reaching task

1. A gamma-aminobutyric acid (GABA) antagonist, bicuculline methiodide (BMI, 10 micrograms/microliters, 1 microliter), was locally injected into a total of 32 sites in the right premotor cortex (PM) of two rhesus monkeys that had been well-trained in a visually guided reaching task (VR) for approximately 3 yr. The monkey initiated the task by pressing a central hold lever with its left hand, and this was followed by waiting (1 s), warning (central green square on a computer monitor, 0.5 s), cue (right, upper, or left square), delay (2-5 s), and go (central green square changes to red, < 1.2 s) periods. In the go period, the monkey released the hold lever and reached out to one of three target levers (left, upper, or right) that had been indicated 2-5 s previously in the cue period. 2. At three sites in the dorsal part of the PM, after the local application of BMI, reaching movements of the left forelimb, which were not part of the trained-reaching, occurred 200-300 ms after the onset of a burst of neuronal activity at the BMI injection site. This induced-reaching, which was designated a "forced-reaching" movement, occurred while the monkeys were pressing the hold lever before the cue appeared-i.e., during the waiting or waiting period. No reaching occurred when the burst did not appear. Furthermore, trajectories and electromyograms of the forelimbs during the forced-reaching movements were similar to those in the trained-reaching movements in the VR task. 3. These results suggest that restricted sites in the dorsal PM of monkeys are involved in the initiation and/or execution of trained-reaching movements and that GABAergic inhibition at these sites normally suppresses this initiation/execution unless it is required. By relaxing GABAergic suppression, the dorsal PM might send a command to a neuronal system that is associated with trained reaching to recruit the system, thereby initiating and/or executing the trained reaching.

Changes in DNA induced by toxic agents

This is a preliminary report on significant alterations in the DNA profile caused by toxic substances which potentially has profound implications for the use of DNA techniques in identification. Acute DNA changes in the globus pallidus of the brain in man caused by carbon monoxide poisoning were detected by DNA profiling with probe 33.15. Chronic DNA changes in rabbits caused by methamphetamine were detected by DNA profiling with probe 33.15, AmpFLP on D1S80, TH01, CSF1PO and TPOX loci. Pre-intoxication bands appeared, disappeared or were discoloured after intoxication. With PCR-dot blot hybridization testing for HLADQ alpha, pre-intoxication positive spots became negative after intoxication and pre-intoxication negative spots became positive after intoxication. Intravenous injection of 10 mg/kg of methamphetamine every 2 days for 2 weeks was a large enough dose for inducement of genetic changes. In this investigation, clear changes in DNA due to intoxication were confirmed.

Modular activation and suppression of neocortical activity in the monkey revealed by optical imaging

To examine functional local connections in the primate neocortex, we examined changes in optical signal by intracortical microstimulation (ICMS), using a voltage-sensitive dye (RH795) in frontal and parietal cortical areas of the anesthetized monkey. ICMS increased the optical signal at the stimulated site, followed by increases and decreases in a modular fashion at regions that were from hundreds of micrometres to a few millimetres from the stimulated site. These changes lasted for 100-250 ms after the offset of ICMS. Further, this increase in the optical signal was accompanied by an increase in electrical activity in the neurones. These findings suggest the presence of excitatory and inhibitory modular connections within the neocortical areas. It is likely that some functional 'modules' are activated concurrently by excitatory loops, which suppress the activity of other modules.

The role of D1-dopamine receptor in working memory: local injections of dopamine antagonists into the prefrontal cortex of rhesus monkeys performing an oculomotor delayed-response task

1. To examine the role of dopamine receptors in the prefrontal cortex (PFC) on working memory, we injected dopamine antagonists (SCH23390, SCH39166, haloperidol, sulpiride, and raclopride) locally into the dorsolateral PFC in two monkeys trained to perform an oculomotor delayed-response (ODR) task. In the ODR task, monkeys fixate a central spot on a cathode ray tube (CRT) monitor while a visual cue is briefly (300 ms) presented in one of several peripheral locations in the visual field. After a delay of 1.5-6 s, the fixation spot is turned off, instructing the monkey to move its eyes to the target location that had been indicated by the visuospatial cue before the delay. Each monkey also performed a control task in which the cue remained on during the delay period. In this task the monkey's response was sensory rather than memory guided. 2. Local intracerebral injection of the selective dopamine antagonists SCH23390 (10-80 micrograms) and SCH39166 (1-5 micrograms) and/or the nonselective dopamine antagonist haloperidol (10-100 micrograms) induced deficits in ODR task performance at a total of 22 sites in the dorsolateral PFC. The deficit was characterized by a decrease in the accuracy of the memory-guided saccade as well as an increase in the latency of the response. The deficit usually appeared within 1-3 min after the injection, reached a peak at 20-40 min, and recovered at 60-90 min. 3. Performance change was restricted to a few specific target locations, which varied with the injection site and were most often contralateral to the injection site. 4. The degree of impairment in the ODR task occasioned by the injection of the dopamine antagonists was sensitive to the duration of delay; longer delays were associated with larger decreases in the accuracy and delayed onset of the memory-guided saccade. 5. The deficit was dose dependent; higher doses induced larger errors and increases in the onset of the memory-guided saccade. 6. Dopamine antagonists did not affect performance on the control task, which required the same eye movements but was sensory guided. Thus, in the same experimental session in which ODR performance was impaired, the accuracy and the latency of the sensory-guided saccades were normal for every target location.(ABSTRACT TRUNCATED AT 400 WORDS)