Assessing a public health approach to delay onset and progression of adolescent substance use: latent transition and log-linear analyses of longitudinal family preventive intervention outcomes

This study examined the effects of the Iowa Strengthening Families Program (ISFP) and the Preparing for the Drug-Free Years program (PDFY) on young adolescent transitions from nonuse of substances to initiation and progression of substance use. Analyses incorporated 3 waves of data collected over a 2.5-year period from 329 rural young adolescents. Outcomes were analyzed by using log-linear models that incorporated substance use status frequencies derived from latent transition analyses. Effects on delayed substance use initiation were shown for both the ISFP and the PDFY at a 2-year follow-up. Also at this follow-up, the PDFY showed effects on delayed progression of use among those previously reporting initiation.

Assessment of functional MR imaging in neurosurgical planning

BACKGROUND AND PURPOSE

Presurgical sensorimotor mapping with functional MR imaging is gaining acceptance in clinical practice; however, to our knowledge, its therapeutic efficacy has not been assessed in a sizable group of patients. Our goal was to identify how preoperative sensorimotor functional studies were used to guide the treatment of neuro-oncologic and epilepsy surgery patients.

METHODS

We retrospectively reviewed the medical records of 46 patients who had undergone preoperative sensorimotor functional MR imaging to document how often and in what ways the imaging studies had influenced their management. Clinical management decisions were grouped into three categories: for assessing the feasibility of surgical resection, for surgical planning, and for selecting patients for invasive functional mapping procedures.

RESULTS

Functional MR imaging studies successfully identified the functional central sulcus ipsilateral to the abnormality in 32 of the 46 patients, and these 32 patients are the focus of this report. In epilepsy surgery candidates, the functional MR imaging results were used to determine in part the feasibility of a proposed surgical resection in 70% of patients, to aid in surgical planning in 43%, and to select patients for invasive surgical functional mapping in 52%. In tumor patients, the functional MR imaging results were used to determine in part the feasibility of surgical resection in 55%, to aid in surgical planning in 22%, and to select patients for invasive surgical functional mapping in 78%. Overall, functional MR imaging studies were used in one or more of the three clinical decision-making categories in 89% of tumor patients and 91% of epilepsy surgery patients.

CONCLUSION

Preoperative functional MR imaging is useful to clinicians at three key stages in the preoperative clinical management paradigm of a substantial percentage of patients who are being considered for resective tumor or epilepsy surgery.

Cytokine production in primary histoculture by human normal kidney, renal cell carcinoma and benign renal angiomyolipoma tissues

In order to understand the ability of normal human kidney, benign renal angiomyolipoma and malignant renal cell carcinoma (RCC) cells to produce cytokines, we determined the IL-1-beta, IL-6, IL-10, IL-11, TNF-alpha and TGF-beta-1 concentration in the supernatant of histoculture specimens according to thymidine labelling indices. From these studies, we conclude that normal, benign and malignant renal tissues are one of the main sources of IL-6 production and patterns of IL-6 production are inversely proportional to thymidine labelling index in normal kidney(r = -0.9). However, IL-6 production is increased in proportion to the increasing thymidine labelling index in benign or malignant tissues (r = 0.94, r = 0.76). There is no production of IL-1-beta, IL-10, IL-11, TNF-alpha or TGF-beta-1. These findings allows many important studies of cytokines in normal, benign and malignant renal disease. Patterns of IL-6 production are different in normal and benign or malignant changed renal disease. There is no overlapping biologic effects among IL-6, IL-1-beta and TNF-alpha. Histoculture supports future studies of these cytokines.

Risk moderation of parent and child outcomes in a preventive intervention: a test and replication

Family risk-related variations in proximal parent and young adolescent outcomes of a universal family-focused preventive intervention were examined using a cumulative index of risk incorporating sociodemographic characteristics and social-emotional adjustment measures. Results of an initial investigation involving 209 families of young adolescents suggested that intervention efficacy was largely unrelated to cumulative family risk. These findings were replicated with a second sample of 428 families. Implications for future intervention applications and outcome research are discussed.

Genomic structure and sequence analysis of human HOXA-9

In order to understand the regulatory mechanisms establishing and maintaining HOXA-9 gene expression, structural information about the gene is a prerequisite. Therefore, we sequenced the 7.2-kb region of the human HOXA-9 gene and mapped the positions of two partial cDNAs consisting of one of two 5' exons, AB (358 bp) or CD (568 bp), and a common 3' exon (exon II), which are separated by 5.4- and 1.0-kb introns, respectively. When the amino acid sequence homologies were compared with those of other Hox genes belonging to the same paralogous group, exon CD exhibited the strongest homology: 73% of 91 aa residues exactly matched those of chicken Hoxa-9. An intermediate exon (90 bp) was detected within exon CD. It was surrounded by a splice acceptor and a donor at both the 5' and 3' ends, and one branchpoint site was found near the splice-acceptor site. Nucleotide sequence analysis along this region revealed two TATA boxes, one CAAT box, one GC box, and one each of the following binding sites--engrailed, eve-stripe2-hb3, and Krox20--just upstream of exon CD. A CpG island and two RARE repeats were detected within intron I. Northern blot analysis showed that at least four main transcripts were generated along this region: all fetal tissues tested (brain, lung, liver, and kidney) produced a 1.8-kb homeobox-containing transcript (HA-9A); a 2.2- and a 3.3-kb transcript were generated from exon CD and exon II (HA-9B), especially in fetal and adult kidneys as well as in adult skeletal muscle; the 1.0-kb transcript was likely to be generated by the intermediate exon in all adult and fetal tissues. Several weak bands without tissue specificity were likely to be contributed by the hybrid transcripts between HOXA-9 and the other HOXA gene(s). Together, these results may account for the unique degree of conservation of the HOX cluster in general.

Direct and indirect latent-variable parenting outcomes of two universal family-focused preventive interventions: extending a public health-oriented research base

Recent literature underscores the need for studies of family-based preventive interventions oriented toward public health objectives. This article illustrates a program evaluation approach for the study of family intervention outcomes in general populations. Thirty-three rural schools were randomly assigned to 1 of 3 conditions: the Preparing for the Drug-Free Years Program (PDFY), the Iowa Strengthening Families Program (ISFP), and a minimal-contact control group. Self-report and observational data collected from 523 families were used to develop measurement models of 3 latent parenting constructs that included measurement method effects. Analyses were conducted to ensure initial and attrition-related group equivalencies and to assess school effects. Structural equation models of the hypothesized sequence of direct and indirect effects for both PDFY and ISFP were then fit to the data. All hypothesized effects were significant for both interventions. The discussion addresses the potential public health benefits of evaluation research on universal preventive interventions.

Effect of cutaneous burn injury and resuscitation on the cerebral circulation in an ovine model

The aim of our study was to evaluate the effects of a large cutaneous burn injury on the cerebral circulation. Anesthetized sheep (n = 8) were prepared with vascular catheters, a urinary catheter and a Richmond bolt for intracranial pressure monitoring. A scald injury was inflicted on 70 percent of total body surface area with hot water. Resuscitation was started 30 min after scald with Ringer's lactate to restore and maintain baseline oxygen delivery. Resuscitation maintained blood pressure, cardiac output and urine output at normal levels. Brain blood flow was measured with colored microspheres. During resuscitation intracranial pressure rose slowly from 10.6 +/- 1.5 to 17.0 +/- 4.0 mmHg (P < 0.05) and cerebral perfusion pressure was reduced from 86.4 +/- 6.8 to 64.1 +/- 2.8 mmHg (P < 0.05). During early resuscitation cerebrovascular resistance declined to maintain brain blood flow and oxygen delivery at baseline or better. After 6 h, mean cerebrovascular resistance was inappropriately increased during a period of reduced cerebral perfusion pressure which resulted in brain blood flow reductions of half the baseline levels. These data suggest that autoregulation maintains brain blood flow immediately after burn shock and early resuscitation, but the autoregulation may be less effective as burn resuscitation proceeds.

Painful generalised clonic and tonic-clonic seizures with retained consciousness

Two patients in whom consciousness and memory were retained during bilateral clonic or tonic-clonic seizures are reported on, and three patients reported on previously are reviewed. Ictal semiology differed from myoclonic and supplementary motor seizures, which are other seizure types characterised by bilateral motor movements and retained awareness. In the two new patients ictal pain was a prominent feature. It is proposed that propagation of seizure activity may be confined to the sensorimotor areas bilaterally while sparing the neural structures involved in maintaining consciousness and in processing language and memory. This unusual type of seizure may be misdiagnosed as a pseudoseizure. Detailed description of the ictal events and further laboratory evaluation including video-EEG monitoring may be necessary to make the distinction.

A prospective validation study of inclination, belief, and context predictors of family-focused prevention involvement

Prior research by the authors tested a model of factors influencing parent inclination to participate in parenting interventions. Family context, belief, attitude, and inclination to participate variables from this model were used to predict the actual participation of 1,121 families in assessment and intervention activities of a family-focused preventive intervention research project. Invitations to the project assessment and intervention components were, respectively, about 6 months and 10 months following the initiation of a telephone survey collecting predictor variable data. Logistic regression analyses examining each predictor individually showed that a number of family context, belief, attitude, and inclination variables were predictive of project participation. Subsequently, multiple logistic regressions were conducted, entering variables by blocks corresponding to theoretical model components. These analyses showed that prospectively stated inclination to participate in a parenting intervention and level of education were consistently significant predictors of both assessment participation and intervention enrollment. Implications for both research and practice are discussed.

Applying readily accessible graphical techniques to assess curvilinear relationships and detect outliers. The case of protective family processes

The purpose of this article is to use data from a study of protective family processes to illustrate how readily accessible graphical techniques can supplement correlation and regression analyses. Graphical techniques can help to (a) better understand family process data from a descriptive standpoint, (b) minimize erroneous statistical conclusions, and (c) clarify theoretically important relationships among variables. Following a brief description of the substantive area selected for illustration of the graphical techniques, data from a study employing multimethod measurement procedures (N = 146) are employed to illustrate two graphical technique applications in the analysis of a predictor (marital quality) of a study outcome variable (parent-child affective quality). Instructions for the application of relevant procedures in SAS and SPSS statistical packages are provided.

Occupational injury and illness in the United States. Estimates of costs, morbidity, and mortality

OBJECTIVE

To estimate the annual incidence, the mortality and the direct and indirect costs associated with occupational injuries and illnesses in the United States in 1992.

DESIGN

Aggregation and analysis of national and large regional data sets collected by the Bureau of Labor Statistics, the National Council on Compensation Insurance, the National Center for Health Statistics, the Health Care Financing Administration, and other governmental bureaus and private firms.

METHODS

To assess incidence of and mortality from occupational injuries and illnesses, we reviewed data from national surveys and applied an attributable risk proportion method. To assess costs, we used the human capital method that decomposes costs into direct categories such as medical and insurance administration expenses as well as indirect categories such as lost earnings, lost home production, and lost fringe benefits. Some cost estimates were drawn from the literature while others were generated within this study. Total costs were calculated by multiplying average costs by the number of injuries and illnesses in each diagnostic category.

RESULTS

Approximately 6500 job-related deaths from injury, 13.2 million nonfatal injuries, 60,300 deaths from disease, and 862,200 illnesses are estimated to occur annually in the civilian American workforce. The total direct ($65 billion) plus indirect ($106 billion) costs were estimated to be $171 billion. Injuries cost $145 billion and illnesses $26 billion. These estimates are likely to be low, because they ignore costs associated with pain and suffering as well as those of within-home care provided by family members, and because the numbers of occupational injuries and illnesses are likely to be undercounted.

CONCLUSIONS

The costs of occupational injuries and illnesses are high, in sharp contrast to the limited public attention and societal resources devoted to their prevention and amelioration. Occupational injuries and illnesses are an insufficiently appreciated contributor to the total burden of health care costs in the United States.

A high-risk group for prostatism: a population-based epidemiological study in Korea

OBJECTIVE

To evaluate the effect of sociodemographic, dietary and physical factors on prostatism in Korean men aged 50 and over.

SUBJECTS AND METHODS

A community-based cross-sectional epidemiological study was performed in Yonchon County, Korea. The Korean version of the International Prostate Symptom Score (IPSS) was used to assess the severity of prostatism. Data on occupation, marital status, education, smoking habits, alcohol intake, daily consumption of nutrients, body mass index, abdominal circumference, waist-to-hip ratio, blood pressure, serum glucose, cholesterol, triglyceride and high-density lipoprotein (HDL) levels were analysed. The age-adjusted relative risk of these factors was calculated for moderate to severe prostatism (IPSS > or = 8). A multivariate analysis of all significant factors was performed to examine the joint effect of risk factors.

RESULTS

Of 514 subjects, 119 (23.2%) had moderate to severe prostatism, the risk for which was related to age and alcohol consumption; waist-to-hip ratio (which represents the degree of abdominal obesity) and the serum level of HDL showed a biphasic association with prostatism in the multivariate analysis.

CONCLUSION

In addition to previously reported risk factors, these data suggest that there might be an association between the development of prostatism and abnormal lipid metabolism.

Rapid analysis for the isolation of novel genes encoding putative effectors to the position-specific regulatory element of murine Hoxa-7

Hox genes are known to play a critical role in pattern formation during vertebrate development by being expressed at the specific time and in the specific position along the antero-posterior body axis. In order to understand the regulatory mechanism for the position-specific expression of murine Hoxa-7, yeast one-hybrid system was applied. DNA fragment conferring a position specificity to the Hoxa-7 gene was placed just upstream from the yeast CYC1 promoter and lacZ gene in a reporter. Selection of LacZ positive clones after cotransformation of the reporter and mouse embryonic cDNA library as an effector, which was designed to be expressed as fusion proteins to the GAL4 activation domain, allowed us to isolate putative factors interacting with the position-specific regulatory element of murine Hoxa-7. A total of 28 positive clones were screened from 5 x 10(5) yeast transformants. About 70% of the clones turned out to be novel and most of the candidate clones selected in this study showed a temporally restricted expression pattern during embryonic development, suggesting that this method could provide an efficient way for isolating novel genes whose expressions are temporally regulated during embryogenesis.

Calmodulin in ischemic neurotoxicity of rat hippocampus in vitro

To determine whether calmodulin plays a role in neurodegeneration after ischemia, effects of the selective calmodulin inhibitors calmidazolium and W7 were studied in organotypic cultures of rat hippocampus. Protection of pyramidal cells in the CA1 region of the hippocampus by calmidazolium and W7 against hypoxia/hypoglycemia suggests that activation of intracellular calmodulin plays a significant role in ischemic neuronal injury. Both ryanodine and TMB-8, inhibitors of intracellular Ca2+ release, failed to prevent ischemic neuronal injury. These results indicate that calmodulin, a major intracellular Ca2+ binding protein, plays a significant role in experimental ischemia-induced hippocampal neuronal injury in vitro.

Reversible parkinsonism and cognitive impairment with chronic valproate use

Following our initial report of the insidious development of reversible, valproate-induced hearing, motor, and cognitive dysfunction in two patients, we evaluated 36 patients in an epilepsy clinic who had been taking therapeutic levels of valproate for at least 12 months; 29 of these patients were examined according to a prospective protocol. We observed varying degrees of parkinsonism and cognitive impairment, from none to severe. Discontinuation of valproate in 32 affected patients led to subjective and objective improvement on follow-up testing at least 3 months later. Improvement was greatest in patients who were affected most. We conclude that a syndrome of reversible parkinsonism and cognitive impairment may develop insidiously in patients who have been treated with valproate for more than 12 months. The association with valproate may be overlooked due to the insidious onset.

The loop B domain is physically separable from the loop A domain in the hairpin ribozyme

In order to understand the catalysis mechanism of the hairpin ribozyme, mutant ribozymes were constructed. The distance between the loop A domain and the loop B domain was extended by inserting various lengths of nucleotide linkers at the hinge region in cis mutants, or the domains were separated physically in a trans mutant. All the mutant ribozymes, including the trans mutant, could cleave substrate RNA at the predicted site. A cis mutant with a single nucleotide insertion exhibited cleavage activity about twice as high as that of the wild-type (wt) ribozyme. The insertion of 2-5 nucleotides (nt) gradually reduced the activity to the level of the wt ribozyme. Insertion of a longer linker, up to 11 nt, resulted in the reduction of activity to one half of that of the wt ribozyme. The ribozyme with a single nucleotide insertion at the hinge region seems to form a more suitable conformation for catalysis by three-dimensional fold-back of the loop B to loop A containing the cleavage site. The trans mutant, in which the A and B domains were physically separated, maintained a significant level of activity, suggesting that both domains are necessary for catalysis, but separable. These results demonstrate that interaction between the A and B domains results in catalysis.

Routine EEG and temporal lobe epilepsy: relation to long-term EEG monitoring, quantitative MRI, and operative outcome

PURPOSE

To investigate the relation among routine EEG, long-term EEG monitoring (LTM), quantitative magnetic resonance imaging (MRI), and surgical outcome in temporal lobe epilepsy (TLE).

METHODS

We evaluated 159 patients with intractable TLE who underwent an anterior temporal lobectomy between 1988 and 1993. The epileptogenic temporal lobe was determined by ictal LTM. A single awake-sleep outpatient EEG with standard activating procedures was performed before LTM. EEGs were analyzed by a blinded investigator.

RESULTS

MRI scans showed unilateral medial temporal atrophy (109 patients) or symmetrical hippocampal volumes (50 patients). The surgically excised epileptogenic brain tissue revealed mesial temporal sclerosis, gliosis, or no histopathologic alteration. Routine EEG revealed temporal lobe epileptiform discharges in 123 patients. Routine EEG findings correlated with the temporal lobe of seizure origin (p < 0.0001) and the results of MRI volumetric studies (p < 0.0001). Interictal epileptiform discharges were seen only during LTM in 24 patients. Routine EEG was disconcordant with interictal LTM in another 20 patients. MRI-identified unilateral medial temporal lobe atrophy was a strong predictor of operative success (p < 0.0001). There was no significant relation between the routine EEG findings and operative outcome (p > 0.20).

CONCLUSIONS

Results of this study modified our approach in patients with TLE. Interictal epileptiform discharges localized to one temporal lobe on serial routine EEGs or during LTM may be adequate to identify the epileptogenic zone in patients with MRI-identified unilateral medial temporal lobe atrophy.

Helical periodicity of GA-alternating triple-stranded DNA

Homopurine-homopyrimidine tracts (18 or 28 bp) containing predominantly GA-alternating sequences were inserted between two bent DNA loci composed of six (dA)6.(dT)6 repeats. For each homopurine tract, the DNA length between the bent DNA loci was varied by one base pair over a full helical turn. The two series of bent DNA fragments were electrophoresed in 5% polyacrylamide gel to measure the gel mobilities, which reflected the overall extent of DNA bending of each DNA fragment. By comparing the gel mobilities between the two series of bent DNA fragments, the helical periodicity of the GA-alternating duplex was determined to be 10.4 bp/turn. The two series of bent DNA fragments were also electrophoresed upon formation of the intermolecular triplex at the homopurine.homopyrimidine tracts. Comparison of the gel mobilities between the two series of DNA fragments showed that the helical periodicity of triplexed DNA of GA-alternating sequence was 11.2 bp/turn. Triplexed DNA with homopurine and homopyrimidine oligodeoxyribonucleotides had the same helical periodicity, while hybrid triplex DNA associated with homopyrimidine oligoribonucleotide had a slightly more wound structure with 11.1 bp/turn.

Electrocorticography and temporal lobe epilepsy: relationship to quantitative MRI and operative outcome

We investigated the relationship between electrocorticography (ECoG), quantitative magnetic resonance imaging (MRI), and surgical outcome in 165 patients with intractable nonlesional temporal lobe epilepsy (NLTLE). A standard mesial temporal resection was performed in all patients. Patients with an operative follow-up < 1 year were excluded from the study. The extent of the lateral temporal neocortex resection (LCR) was guided by ECoG and the side of surgery. The extent of the LCR was not predictive of seizure outcome in patients with or without hippocampal formation atrophy (p > 0.5). Patients undergoing a right anterior temporal lobectomy had a larger LCR (p < 0.0001), but the side of surgery was not of predictive value in determining seizure outcome (p > 0.1). The topography of the acute intracranial spikes did not correlate with operative outcome (p > 0.5) and was independent of hippocampal volumetric studies (p > 0.5). The postexcision ECoG was also shown not to be of prognostic importance (p > 0.5). Our results indicates that the extent of the lateral temporal cortical resection and the ECoG findings are not important determinants of surgical outcome in patients with NLTLE.

Differences in the anatomic distribution of immediate-early gene expression in amygdala and angular bundle kindling development

Kindling is a model in which fleeting changes of neuronal activity produce a lifelong modification of neuronal structure and function in the mature nervous system. Immediate-early genes (IEGs) such as c-fos have been implicated as a causal link in the chain of molecular events coupling fleeting pathologic activity to lasting hyperexcitability. Identification of the brain structures exhibiting IEG expression during the evolution of kindling is necessary to guide investigations of the phenotypic consequences. We used in situ hybridization histochemistry to identify the structures exhibiting expression of multiple IEGs during the evolution of amygdala kindling and compared this to the pattern following angular bundle kindling. The principal findings included that: (1) generalized limbic and clonic motor (class 5) kindled seizures evoked by stimulation of one amygdala induced the expression of IEGs in a small subset of limbic structures with remarkable symmetry between the two hemispheres; (2) the anatomic extent of seizure-evoked expression of c-fos mRNA expanded progressively following focal limbic and motor (classes 0-3) seizures during the development of amygdala kindling; c-fos mRNA was detected first ipsilaterally in AM, ACO, and PC and with higher-class seizures in hippocampal formation and homologous structures contralaterally, and (3) class 5 seizures evoked by stimulation of two different sites in the limbic system (amygdala or angular bundle) induced IEG expression in distinct but partially overlapping anatomic structures. We propose that synaptic activation of glutamate receptors contributes to the expression of these diverse IEGs throughout the forebrain. The findings provide a constellation of anatomic structures in which to investigate the structural and functional consequences of IEG expression.

Mechanism of epilepsy

Epilepsy is a collection of diverse disorders that together affect approximately 1% of the general population. Current therapies are largely symptomatic and are aimed at controlling seizures in affected individuals. This review focuses on emerging insights into mechanisms underlying the most common form of epilepsy--complex partial epilepsy--and also addresses progress in molecular genetic approaches. Such developments will hopefully lead to more effective therapies.

Migration cost externality and interregional equilibrium

"This paper will investigate the characteristics of population allocation between two regions in the presence of migration cost. It will also examine both populations and the non-migration range of the initial population in which migration does not occur, in social optimum and market equilibrium with central government intervention, to reveal migration cost externality, and to propose a remedy for it." The author finds that "migration cost gives the social planner an additional burden of population reallocation, and it has an important effect upon an individual's decisions on migration in a decentralized market mechanism."

Induction of c-fos mRNA by kindled seizures: complex relationship with neuronal burst firing

Expression of the immediate-early gene c-fos has been advanced as a marker of neuronal activity in the adult nervous system. We sought to test the validity of c-fos mRNA expression as a marker of neuronal activity during seizures and to elucidate specific neurotransmitter receptors whose activation was necessary for seizure-evoked c-fos mRNA expression. We correlated c-fos mRNA expression, measured with in situ hybridization, with kindled seizure-induced firing of hippocampal dentate granule cells or substantia nigra pars compacta and pars reticulata neurons. We found that the occurrence of seizure-evoked synchronous action potentials during the seizure exhibited a perfect qualitative correlation with the presence of c-fos mRNA expression in the granule cells 30 min following the seizure (Fisher's exact test, p = 0.002). However, there was no quantitative correlation between the number of seizure-induced population action potentials and the magnitude of c-fos mRNA expression in the granule cells. In the substantia nigra, where neuronal populations have previously been demonstrated to exhibit synchronous firing during kindled seizures, no induction of c-fos mRNA was detected in either pars compacta or pars reticulata. Pretreatment with antagonists of the NMDA subtype of glutamate receptor selectively and markedly decreased seizure-induced c-fos mRNA expression in the dentate granule cells, despite increasing the number of granule cell population action potentials. These findings illustrate the complexity of the relationship between c-fos induction and neuronal burst firing during kindled seizures.(ABSTRACT TRUNCATED AT 250 WORDS)

NMDA-receptor mediated electrical epileptogenesis in the organotypic culture of rat hippocampus

Extracellular field recordings were made in CA1 in the hippocampal explant cultures in oxygenated artificial cerebrospinal fluid. Schaffer collaterals were stimulated with 1-s trains of 60 Hz pulses every 10 min. Seizures were reliably elicited with progressive lengthening over 1-2 h. D-APV, an N-methyl-D-aspartate (NMDA) antagonist, stereoselectively blocked the development of seizures. Thus we have demonstrated that in vitro epileptogenesis occurs in hippocampal explant cultures through NMDA receptor mediated mechanisms.

Differential expression of immediate early genes in the hippocampus in the kindling model of epilepsy

Kindling is a phenomenon in which brief afterdischarges (ADs) evoked by periodic electrical stimulation of the brain eventually result in generalized clonic motor seizures. Once present, the enhanced sensitivity to electrical stimulation is lifelong. The mechanism by which brief ADs produce this long-lasting effect may involve a change in gene expression. To begin to investigate changes in gene expression that occur during kindling, we used in situ hybridization histochemistry to examine the time course of expression of mRNAs of the immediate early genes (IEGs) c-fos, c-jun, NGFI-A, and c-myc within the dorsal hippocampus of rats following a kindling AD. Three principal findings resulted from this study. First, the expression of all mRNAs except c-myc was significantly increased (P less than 0.05) within discrete neuronal populations. Second, the time course of expression of the IEGs differed markedly within the same neuronal population. Third, for a given IEG, the time course and anatomic pattern of expression were strikingly different among different neuronal populations of the hippocampus. The prolonged and distinctly different patterns of IEG expression suggest that target genes are differentially regulated in these neuronal populations for prolonged periods following a kindling AD.

Antiepileptogenic effects of conventional anticonvulsants in the kindling model of epilespy

We sought to determine whether the clinically effective anticonvulsant drug valproate exhibited antiepileptogenic properties in the kindling model (we use the term anticonvulsant to mean suppression of seizure, and antiepileptogenic to mean suppression of development of epilepsy). We compared and contrasted valproate with two other anticonvulsant drugs, phenobarbital and carbamazepine. We investigated the effects of these drugs on the development of kindling, that is, the number of stimulation-induced afterdischarges required to induce enhanced seizure susceptibility in rats. Valproate exhibited powerful antiepileptogenic effects as evident in a dose-dependent increase in the number of afterdischarges required to induce kindling. These effects were not due to retained valproate or an active metabolite merely masking the expression of kindled seizures. By contrast, carbamazepine was devoid of any antiepieptogenic effects despite exhibiting marked anticonvulsant effects. Like valproate, phenobarbital exhibited both antiepileptogenic and anticonvulsant properties, but its antiepileptogenic properties were significantly less pronounced. The antiepileptogenic effects of valproate and phenobarbital strengthen the candidacy of these agents for the clinical studies needed to investigate pharmacological prevention of the development of epilepsy in high-risk groups.

Sensorineural hearing loss: a reversible effect of valproic acid

We report 2 patients over the age of 70 who, while on valproate (VPA) for complex partial seizures, developed sensorineural hearing loss. Following discontinuation of VPA for nonaudiologic reasons, the patients reported improved hearing which was confirmed by audiometry. These findings represent VPA-induced sensorineural hearing loss, possibly in preexisting presbycusis.

Induction of c-fos mRNA expression by afterdischarge in the hippocampus of naive and kindled rats

Periodic induction of focal electrical seizure [afterdischarge (AD)] is an absolute prerequisite for the development of kindling, an animal model of complex partial epilepsy. Once established, it is a permanent condition. The mechanism(s) that translate ADs, which last tens of seconds, into life-long alterations in the CNS is unclear. Cellular immediate-early genes have been implicated in the conversion of short-term stimuli to long-term alterations in cellular phenotypes by regulating target gene expression. We have investigated the contribution of one such early gene, c-fos, to this process. The relationship between ADs and expression of c-fos gene in the rat hippocampus, a key structure in kindling development, was studied by analysis of mRNA levels. The low constitutive expression of c-fos mRNA in the hippocampus was not altered by kindling. There was an "all-or-none" relationship between induction of c-fos and the duration of AD. The threshold for induction was approximately 30 s of AD. Above-threshold ADs induced c-fos in both naive and kindled animals to the same extent and with identical temporal profiles. Although the expression of c-fos is unchanged with kindling, c-fos may nonetheless contribute to many long-term changes of kindling, both adaptive and epileptogenic.

Inhibition of muscarinic-coupled phosphoinositide hydrolysis by N-methyl-D-aspartate is dependent on depolarization via channel activation

The intent of this work was to elucidate the mechanism by which N-methyl-D-aspartate (NMDA) receptor agonists inhibit a second messenger system, namely, the stimulation of phosphoinositide (PI) hydrolysis activated by muscarinic cholinergic receptor agonists. NMDA inhibited cholinergic stimulation of PI hydrolysis in a dose- and time-dependent manner. NMDA exerts this effect indirectly through channel activation, because both MK-801 and N-[1-(2-thienyl)cyclohexyl]piperidine (TCP) prevented this action. Prevention of the NMDA effect by removal of sodium, but not calcium, from the incubation buffer suggested that depolarization may be the responsible mechanism. Depolarization alone proved sufficient to inhibit cholinergic activation of PI hydrolysis, because both veratridine and an elevated extracellular potassium level inhibited cholinergic stimulation of PI hydrolysis. The effect of NMDA appeared to require sodium flux through NMDA channels rather than through voltage-dependent sodium channels, because tetrodotoxin failed to inhibit the effect of NMDA. In correlative electrophysiologic experiments, NMDA profoundly inhibited evoked excitatory postsynaptic potentials and population action potentials of CA1 neurons, an effect almost certainly due to depolarization. The dose and time course of the electrophysiologic effects correlated well with the biochemical effects. Taken together, the data support the assertion that NMDA receptor activation inhibits PI hydrolysis by depolarization mediated by sodium flux through NMDA channels.

Intravenous phenytoin is an effective anticonvulsant in the kindling model

We reexamined the efficacy of the clinically effective anticonvulsant drug phenytoin in the kindling model. We investigated the effects of varying doses of intravenous phenytoin on serum concentrations and on several indexes of stimulation-evoked kindled seizures. Intravenous phenytoin produced a dose-dependent increase in serum phenytoin concentration and powerfully suppressed both limbic and clonic motor seizures. Although focal afterdischarge threshold was elevated to some extent, the most profound effect of phenytoin was limitation of seizure propagation. Variable and low serum concentrations of intraperitoneal or oral phenytoin may explain previous findings that phenytoin is only partly effective or ineffective against kindled seizures. Together with previous results with other drugs, the excellent correlation among drugs effective against human and kindled seizures strengthens the validity of this model. We suggest that the efficacy of experimental anticonvulsant drugs be established in the kindling model before initiation of clinical trials for partial and secondarily generalized seizures.

Microinjection of a benzodiazepine into substantia nigra elevates kindled seizure threshold

The purpose of these experiments was to initiate investigations of the brain site(s) at which the benzodiazepines exert their anticonvulsant effect. We examined the effects of microinjections of clonazepam into substantia nigra (SN) on seizure threshold in the kindling model. We also examined the distribution of microinjected [3H]methylclonazepam with autoradiographic methods. Microinjection of clonazepam bilaterally into substantia nigra pars reticulata (SNR), but not nearby, produced a 75% elevation of generalized seizure threshold. Quantitative analysis of autoradiographic studies indicated that the vast majority of [3H]methylclonazepam was distributed within 400 micron of the injection cannula tip; even optimally placed injections did not result in drug access throughout the entire SN. The data demonstrate that local application of an anticonvulsant benzodiazepine to the substantia nigra alone is sufficient to suppress seizures. We suggest that the substantia nigra is one site at which systemically administered benzodiazepines act to suppress seizures.

The role of substantia nigra in the development of kindling: pharmacologic and lesion studies

The role of substantia nigra (SN) in the development of kindling was investigated. Microinjection of gamma-vinyl gamma-aminobutyric acid (GVG), a gamma-aminobutyric acid (GABA) transaminase inhibitor, into the SN bilaterally retarded kindling development by 77%. GVG injected dorsal to the SN did not alter the kindling rate. By contrast, lesions of the SN, whether by thermocoagulation or by microinjected neurotoxin, N-methyl-D,L-aspartate, facilitated kindling development by 27-44%. Thermocoagulative lesions dorsal to the SN did not affect the rate of kindling development. Thus these two manipulations, each presumed to suppress the activity of the SN, resulted in opposite effects on kindling development. We interpret the pharmacologic findings to indicate that the intact SN can powerfully facilitate kindling development. However, the SN is not vital for kindling development, since kindling can be established after destruction of a considerable portion of SN. Whether the increased rate of kindling development following SN lesions is due solely to the absence of SN remains unclear.

Stimulation of substantia nigra pars reticulata enhances dentate granule cell excitability

We studied the effects of electrical and chemical stimulation of the substantia nigra (SN) on the dentate granule cell (DGC) response to perforant path stimulation. Studies were carried out in both pentobarbital anesthetized and awake freely moving rats. Chemical stimulation was achieved by microinjection of N-methyl-D,L-aspartate (NMDA), an excitatory amino acid. Electrical preconditioning stimulation applied to the area of the SN, but not dorsal to SN, increased the excitability of DGCs. Intracerebral microinjection of NMDA into the contralateral SN pars reticulata (SNR), but not into SN pars compacta or cerebral peduncle, also produced a marked and reversible enhancement of DGC excitability. In both instances, the increased DGC excitability consisted of increased amplitude of the perforant path evoked population spike without change in the slope of the population excitatory postsynaptic potential (pEPSP). We interpret the data to indicate that increasing the output of the SNR increases the excitability of the DGCs, a limbic neuronal population regulating information transfer through hippocampal pathways. Together with our previous finding that decreasing the output of SNR suppressed limbic seizures, these data demonstrate that the SNR exerts a powerful influence on limbic system excitability. Delineating the anatomic pathway mediating this influence could provide valuable insight into the mechanisms underlying basal ganglia-limbic interactions in both physiologic and pathologic conditions.

Anti-seizure and anti-epileptogenic effect of gamma-vinyl gamma-aminobutyric acid in amygdaloid kindling

We examined the effects of systemic administration of gamma-vinyl gamma-aminobutyric acid (GVG), a gamma-aminobutyric acid (GABA) transaminase inhibitor, on the kindling model of epilepsy in rats. GVG (1200 or 1500 mg/kg) approximately doubled the number of stimulations required for kindling development. GVG also suppressed both generalized motor seizures and electrographic after discharges in previously fully kindled animals. These results further support the idea that enhanced GABAergic neurotransmission suppresses both seizures and epileptogenesis. The results also suggest that GVG may be an effective anti-seizure and anti-epileptogenic agent in humans.

Changes in dynorphin, enkephalin and cholecystokinin content of hippocampus and substantia nigra after amygdala kindling

Amygdaloid kindling of rats produced an increase in hippocampal Met5-enkephalin-Arg6-Gly7-Leu8 and cholecystokinin immunoreactivities and simultaneously a decrease in dynorphin A1-8 content. In substantia nigra Met5-enkephalin-Arg6-Gly7-Leu8 was increased and no change was observed in dynorphin A1-8 content. These data suggest that specific alterations of neuropeptides in limbic and extrapyramidal circuits are prominent manifestations of the kindling process or kindled seizures.

gamma-Aminobutyric acid and benzodiazepine receptors in the kindling model of epilepsy: a quantitative radiohistochemical study

Quantitative radiohistochemistry was utilized to study alterations of gamma-aminobutyric acid (GABA) and benzodiazepine receptors in the kindling model of epilepsy. The radioligands used for GABA and benzodiazepine receptors were [3H] muscimol and [3H]flunitrazepam, respectively. GABA receptor binding was increased by 22% in fascia dentata of the hippocampal formation but not in neocortex or substantia nigra of kindled rats. Within fascia dentata, GABA receptor binding was increased to an equivalent extent in stratum granulosum and throughout stratum moleculare; no increase was found in dentate hilus or stratum lacunosummoleculare or stratum radiatum of CA1. The increased binding was present at 24 hr but not at 28 days after the last kindled seizure. The direction, anatomic distribution, and time course of the increased GABA receptor binding were paralleled by increased benzodiazepine receptor binding. Unexpectedly, GABA receptor-mediated enhancement of benzodiazepine receptor binding was slightly attenuated in fascia dentata of kindled compared to control rats. The anatomic distribution of the increased GABA receptor binding is consistent with a localization to somata and dendritic trees of dentate granule cells. We suggest that increased GABA and benzodiazepine receptor binding may contribute to enhanced inhibition of dentate granule cells demonstrated electrophysiologically in kindled animals.

High-resolution computed tomography in multiple sclerosis

Eighty-five patients were classified as having definite (n = 34), probable (n = 18), or possible (n = 33) multiple sclerosis using the criteria of Poser. Each patient had an enhanced computed tomographic examination, and most had cerebrospinal fluid and evoked response studies at the same time. Abnormalities including focal decreased brain density, abnormal enhancement, and cerebrospinal fluid space enlargement were found in 62% of patients (85% of those with definite, 39% of those with probable, and 52% of those with possible multiple sclerosis), and abnormal enhancing areas were demonstrated in 29% (44% of those with definite, 17% of those with probable, and 21% of those with possible disease). In the subgroup of patients with definite multiple sclerosis and recent clinical exacerbation (within the prior 8 weeks), abnormal enhancement was present in 89%. There was a strong correlation between clinical exacerbation and abnormal contrast enhancement. Cerebrospinal fluid studies (IgG, white blood cell count, total protein) had no correlation with exacerbation or abnormal enhancement. Maps of low-density and enhancing areas were similar to those previously described in postmortem studies. Computed tomography thus provides an in vivo, objective, and anatomically specific map of the brain parenchyma and the integrity of the blood-brain barrier that is useful in research studies evaluating the treatment of multiple sclerosis. It is also useful in patients in whom the diagnosis of multiple sclerosis is suspected but not certain on the basis of clinical and laboratory evaluation.

Evidence implicating substantia nigra in regulation of kindled seizure threshold

We studied the effects of microinjected drugs and brainstem lesions on motor and limbic seizures in the kindling model of epilepsy. The duration of motor seizures was determined by timing the colonic and tonic movements of the extremities. The duration of limbic seizures was determined by measuring afterdischarge recorded on the electroencephalogram. Bilateral microinjection of a gamma-aminobutyric acid (GABA) agonist, muscimol, into the area of the substantia nigra (SN) markedly suppressed both motor and limbic seizures induced by stimulation of amygdala, olfactory structures, or lateral entorhinal cortex. Microinjection of saline did not suppress seizures. The suppressive effect of muscimol: (i) dissipated after several hours and was dependent on dose; (ii) was due to an elevation of the seizure threshold, since typical seizures could be elicited with electrical current far exceeding the threshold; and (iii) exhibited spatial specificity since muscimol injections 1 to 2 mm dorsal to the SN or into neocortex did not suppress the seizures. The actions of muscimol were probably mediated by its GABA agonist properties, since microinjection of an irreversible inhibitor of GABA transaminase (gamma-vinyl GABA) into the area of the SN also suppressed kindled seizures. Destruction of brainstem structures was produced by microinjection of the neurotoxin, N-methyl-D,L-aspartate. Seizures were markedly suppressed in animals with bilateral destruction of the SN but not in animals in which the SN was spared bilaterally. We interpret the data to indicate that the SN is the site at which the GABA agonists and lesions act to raise the threshold for kindled seizures. The suppression of limbic seizures indicates that this brainstem nucleus can regulate the intrinsic neuronal excitability of hemispheric sites.

Conversion of ischemic to hemorrhagic infarction by anticoagulant administration. Report of two cases with evidence from serial computed tomographic brain scans

Anticoagulant therapy is appropriate for embolic cerebral infarction due to valvular heart disease or cardiac dysrhythmia, as well as for stroke-in-evolution. Various incidences of hemorrhagic complications have been cited in patients given anticoagulants after stroke or transient cerebral ischemia. Conversion of ischemic to hemorrhagic infarction has been shown to occur experimentally. We describe two patients in whom this conversion occurred in the absence of hypertension or excessive anticoagulation and was substantiated by serial computed tomographic brain scans. This finding suggests that conversion of ischemic to hemorrhagic infarction may occur even with appropriate and carefully administered anticoagulation therapy.

Studies on the blood of an MiV/Mk proposita and her family

An individual (J-1) was shown to be heterozygous for the MiV and Mk genes. Her red cells typed as M+(weak), N-, S-, s+(strong), U+, Hil+, Wr(a-b-), En(a+weak). Polyacrylamide gel electrophoresis analysis of her red cell membranes revealed absence of PAS-staining bands corresponding to normal MN and Ss sialoglycoprotein (SGP), and presence of a hybrid MNSs SGP [(alpha-delta)MiV] similar but not identical to that reported for an MiV homozygote. However, J-1 cannot be homozygous for MiV since the red cells of two of her children are Hil- and s-, carry only a single dose of M antigen, and have a sialic acid content that is consistent with the presumption that they are Mk heterozygotes. J-1's hybrid MNSs SGP is considered to be gene-fusion product resulting from unequal crossover between a normal alpha M and delta gene, and her red cells lack that portion of the Ena antigen that is resistant to ficin. Her hybrid MNSs SGP differs, therefore, from that reported for the MiV homozygote, which probably arose from unequal crossover between alpha N and delta genes. Further, the red cells of the MiV homozygote carry the ficin-resistant Ena determinant.