Hepatitis C virus infection in cocaine users--a silent epidemic.

Over a recent three year period, approximately 600 individuals responded to newspaper advertisements for research studies requiring healthy, cocaine using subjects. These subjects were screened using a standard phone interview in order to eliminate individuals with known medical or psychiatric illnesses that would exclude them from ongoing neuroimaging studies of drug abuse. Individuals were specifically asked about their hepatitis and HIV status. Of these, 170 subjects passed the phone screen, having no known medical or psychiatric illness outside of cocaine abuse/dependence and were willing to be further evaluated for the studies. These subjects were brought to the Medical College of Wisconsin's General Clinical Research Center and tested for, among other measures, hepatitis B, hepatitis C, and HIV. Of these, 144 completed the examination and all testing. In this cohort of assumed healthy subjects, 47 (33%) tested positive for antibodies to the hepatitis C virus (HCV). Only 7 (5%) tested positive for the hepatitis B surface antigen and 2 (1.4%) to HIV. The demographics of this cohort are 56% African-American, 81% male, 75% never-married, 55% unemployed with a mean age of 36 years. The percentage of subjects reporting any lifetime intravenous drug use among the HCV(+) and the HCV(-) cohorts was 77% vs. 29% respectively. Some routes of HCV transmission are still unclear and may reflect lifestyle or other factors related to cocaine use outside of parenteral drug use. Since almost all HCV infections become chronic, and many progress to chronic active hepatitis, cirrhosis, and ultimately hepatocellular carcinoma, these observations suggest a significant epidemic in an unsuspecting population with little regular access to health care. These individuals also form a large pool for the continued transmission of HCV to the general population. Additional public health interventions are suggested.

When academic performance is higher than WISC-III IQs, is the sequential-processing model of intelligence the preferred approach to assessment?

The WISC-III is probably the most widely used measure of intelligence for children of school age. On occasion, an unusual psychometric profile emerges in which academic ability is much higher than would be expected for IQ. Initial data for 8 children suggest that the sequential-processing model of intelligence may be the preferred approach to assessment in such situations.

Case reports in autism: issues in diagnosis and treatment.

Autism is a relatively common developmental disorder characterized by pervasive impairments in communication and social interaction as well as restricted interests and repetitive behaviors. Two case reports are presented to illustrate important aspects of diagnosis and treatment. Early clinical diagnosis is essential so that appropriate intervention can be implemented. A multidisciplinary approach to treatment is recommended due to the impact of autism on many aspects of behavior and development.

Ebola hemorrhagic fever, Kikwit, Democratic Republic of the Congo, 1995: risk factors for patients without a reported exposure.

In 1995, 316 people became ill with Ebola hemorrhagic fever (EHF) in Kikwit, Democratic Republic of the Congo. The exposure source was not reported for 55 patients (17%) at the start of this investigation, and it remained unknown for 12 patients after extensive epidemiologic evaluation. Both admission to a hospital and visiting a person with fever and bleeding were risk factors associated with infection. Nineteen patients appeared to have been exposed while visiting someone with suspected EHF, although they did not provide care. Fourteen of the 19 reported touching the patient with suspected EHF; 5 reported that they had no physical contact. Although close contact while caring for an infected person was probably the major route of transmission in this and previous EHF outbreaks, the virus may have been transmitted by touch, droplet, airborne particle, or fomite; thus, expansion of the use of barrier techniques to include casual contacts might prevent or mitigate future epidemics.

Determination of drug-induced changes in functional MRI signal using a pharmacokinetic model.

As the applications of functional magnetic resonance imaging (fMRI) expand, there is a need for the development of new strategies for data extraction and analysis that do not require the presentation of stimuli in a repeated on/off pattern. A description and evaluation of a method and computer algorithm for the detection and analysis of brain activation patterns following acute drug administration using fMRI are presented. A waveform analysis protocol (WAP) input function has been developed that is based upon the single-dose pharmacokinetics of a drug of interest. As a result of this analysis, regional brain activation can be characterized by its localization and intensity of activation, onset of action, time to peak effect, and duration of action. A global statistical test for significant drug effects based upon the probability of a voxel being activated by a saline vehicle injection is applied to grouped data on a voxel by voxel basis. Representative data are presented using nicotine as a prototypical agent. Using this method, statistically significant drug-induced brain activation has been identified in several key cortical and subcortical brain regions.

Nicotine-induced limbic cortical activation in the human brain: a functional MRI study.

OBJECTIVE: Nicotine is a highly addictive substance, and cigarette smoking is a major cause of premature death among humans. Little is known about the neuropharmacology and sites of action of nicotine in the human brain. Such knowledge might help in the development of new behavioral and pharmacological therapies to aid in treating nicotine dependence and to improve smoking cessation success rates. METHOD: Functional magnetic resonance imaging, a real-time imaging technique, was used to determine the acute CNS effects of intravenous nicotine in 16 active cigarette smokers. An injection of saline followed by injections of three doses of nicotine (0.75, 1.50, and 2.25 mg/70 kg of weight) were each administered intravenously over 1-minute periods in an ascending, cumulative-dosing paradigm while whole brain gradient-echo, echo-planar images were acquired every 6 seconds during consecutive 20-minute trials. RESULTS: Nicotine induced a dose-dependent increase in several behavioral parameters, including feelings of "rush" and "high" and drug liking. Nicotine also induced a dose-dependent increase in neuronal activity in a distributed system of brain regions, including the nucleus accumbens, amygdala, cingulate, and frontal lobes. Activation in these structures is consistent with nicotine's behavior-arousing and behavior-reinforcing properties in humans. CONCLUSIONS: The identified brain regions have been previously shown to participate in the reinforcing, mood-elevating, and cognitive properties of other abused drugs such as cocaine, amphetamine, and opiates, suggesting that nicotine acts similarly in the human brain to produce its reinforcing and dependence properties.

Cannabinoid-induced alterations in regional cerebral blood flow in the rat.

A specific receptor for cannabinoids has been characterized at the pharmacological, molecular, and neuroanatomical level. However, less is known of the functional localization in the brain for the behavioral and physiological actions of these drugs. We have examined the effects of delta 9-tetrahydrocannabinol (THC) and its active metabolite 11-OH-THC on regional cerebral blood flow in the rat in order to determine functional CNS sites of action for the cannabinoids. Conscious rats were injected i.v. with one of four doses of THC (0.5, 1, 4, 16 mg/kg). 11-OH-THC (4 mg/kg), or vehicle 30 min prior to sacrifice. Regional cerebral blood flow was determined autoradiographically using the freely diffusible tracer method of Sakaruda et al. Changes in regional cerebral blood flow were observed in 16 of the 37 areas measured. Decreases in regional cerebral blood flow following THC were seen in such areas as the CA1 region of the hippocampus, frontal and medial prefrontal cortex, the nucleus accumbens, and the claustrum. Thresholds for these effects ranged from 0.5 to 16 mg/kg. Areas unaffected by THC include the medial septum, ventral tegmental area, caudate, temporal, parietal and occipital cortex, and cerebellum. These data indicate that THC and its active metabolite, 11-OH-THC, cause a heterogeneous alteration in the activity of specific CNS sites, many of which are involved in the characteristic behavioral actions of THC.

Nonclassical and endogenous cannabinoids: effects on the ordering of brain membranes.

The effects of several nonclassical cannabinoids and the endogenous cannabinoid ligand, anandamide on the lipid ordering of rat brain synaptic plasma membranes (SPM) were examined and compared to delta 9-tetrahydrocannabinol (delta 9-THC). SPM order was determined using fluorescence polarization. All compounds tested affected membrane ordering. delta 9-THC, CP-55,940, CP-55,244 and WIN-55212 decreased lipid ordering in SPM. Some stereospecificity was observed with delta 9-THC and WIN-55212, but not other compounds. Anandamide also decreased lipid order as did its putative precursor, arachidonic acid. In contrast to these compounds, levonantradol increased SPM lipid order. Although all pharmacologically active cannabinoids affect SPM lipid order, potency on this measure does not correlate well with their pharmacological potency. The results of this study suggest that membrane perturbation (either increases or decreases in lipid order) may be a necessary characteristic for cannabinoid pharmacological activity, but it is not a primary or sufficient determinate of action for this class of drugs.

Leukocyte hexokinase activity in aging and Alzheimer disease.

We determined the effects of clinical variables on hexokinase (HK) activity in leukocytes from Alzheimer's disease (AD) patients and controls. Age accounted for 51% of the variance in HK activity in the young and 23% in the old. Duration of illness in both familial and sporadic AD accounted for HK levels by 32 and 38%, respectively. Hexokinase activity increases with age and does not discriminate between familial and sporadic AD.

The role of genetic counseling in visually impaired adolescents.

The presence of genetic disorders in a high percentage of adolescents with significant visual impairments emphasizes the important role that genetic counseling can play in this population. However, its intended goals have been controversial. Responses to structured interviews about genetic counseling services from three groups of former students from the Kentucky School for the Blind were compared. One group consisted of students who had received genetic counseling; another, of students who had declined it; and a third, of students who had graduated before the service was available. In all groups, genetic counseling was viewed as a valuable service which would have been pursued by the majority of those who did not have the opportunity to receive it, and by many of those who refused it initially. Although genetic counseling did little to enhance knowledge of the cause of the specific visual impairment, it appeared to be useful in providing information regarding the risk of visual impairment in future offspring. A relatively high rate of unplanned pregnancies was noted in the group who had refused genetic counseling. The significance of this observation is uncertain. One interpretation is that the group refusing genetic counseling may have consisted of individuals who had fewer concerns as adolescents about family planning issues. These observations suggest that it may be appropriate to recommend to adolescents with significant visual impairments to defer childbearing until independent life experiences are accumulated outside the school setting. Then, prior to considering childbearing, genetic counseling should be sought.

Variability in adaptive behavior in children with developmental delay.

Although diagnosticians have become increasingly sensitized to the importance of assessing adaptive behavior in persons with intellectual delay, few empirical data have been available with respect to the relationship between these two dimensions of development in referred clinical populations. Subjects in this study were 117 children aged 9 to 111 months who had significantly intellectual delay. All subjects were administered the Developmental Profile II (DPII), a parent-report measure of functional and adaptive skills. Seventy-nine percent of the children with mild intellectual delay obtained Self-Help age scores on the DPII and 74.2% Social Age scores that were within broad chronological age expectations. A surprising percentage of children with moderate and severe intellectual delays also obtained adaptive age scores at this level.

Risk of malignancy in Sotos syndrome.

A questionnaire survey identified a possibly increased risk of malignancy for patients with Sotos syndrome. Because the sites and types of neoplasm found in these patients vary, no routine screening except for periodic clinical evaluation seems feasible.

Interactions of flavins with melanin. Studies on equilibrium binding of riboflavin to dopa-melanin and some spectroscopic characteristics of flavin-melanin complex.

Natural melanins are photoprotective pigments that in mammals are principally found in the skin, hair, and eyes. Although the molecular mechanism of photoprotection of pigmented cells has not yet been established, several hypotheses have been proposed with melanin acting as a light filter, free radical scavenger, and quencher of electronically excited states of reactive intermediates. It can be expected that the detoxicating efficiency of melanin should be enhanced if the melanin and potentially cytotoxic species are brought close together. Such a situation may occur for a number of photosensitizing dyes that have the ability to bind to melanin. The interaction of melanin with flavins has been studied under strictly controlled experimental conditions. The equilibrium dialysis method has been employed to determine dissociation constants and the number of binding sites in melanin at pH 5-9. The data reveal that synthetic DOPA-melanin has two different classes of binding sites with dissociation constants of 10(-6) and 10(-5) M, respectively. The overall binding capacity of melanin, at pH 7, is 250 nmol RF/mg melanin. The amount of bound-to-melanin RF increases with pH. The absorption spectra of melanin complexes with RF and lumiflavin indicate that hydrophobic interaction may be involved in the binding of these flavins by melanin. No changes in flavin fluorescence have been detected after binding of flavin to melanin. It appears that, contrary to cationic photosensitizing dyes, the singlet excited state of flavin molecules is not quenched by melanin.

Studies of the role of membrane lipid order in the effects of delta 9-tetrahydrocannabinol on adenylate cyclase activation in heart.

The studies in this report were carried out to investigate the effects of delta 9-tetrahydrocannabinol (delta 9-THC) on cardiac membrane adenylate cyclase activity and to determine the role of changes in membrane lipid order in these effects. delta 9-THC and its psychoactive metabolite, 11-OH-delta 9-THC, increased isoproterenol (ISO) stimulation of adenylate cyclase in rat cardiac ventricular membranes. Cannabidiol, cannabinol and (+)-delta 9-THC were all without effect, indicating that this effect of delta 9-THC is stereoselective and specific for cannabinoids with psychoactive potency. delta 9-THC also increased glucagon stimulation of adenylate cyclase. The enhancement of both ISO and glucagon-stimulated adenylate cyclase was due to an increase in the Vmax of these agonists with no significant change in Kact. delta 9-THC did not affect basal adenylate cyclase activity or the activation of the enzyme by forskolin, guanine nucleotides or fluoride ion. Those cannabinoids which increased ISO-stimulated adenylate cyclase activity also decreased the break temperature of the Arrhenius plot; evidence that the effects of delta 9-THC involve changes in membrane phospholipid order. The effects of the cannabinoids on cardiac membrane phospholipid order were investigated directly using diphenylhexatriene fluorescence polarization. delta 9-THC and 11-OH-delta 9-THC alone decreased the break temperature of the diphenylhexatriene temperature profile, i.e., decreased the temperature of the lipid phase separation. This effect of delta 9-THC was stereoselective.(ABSTRACT TRUNCATED AT 250 WORDS)

The physician under Public Law 99-457.

Public Law 99-457, enacted in 1986, reauthorizes P.L. 94-142 (the Education of all Handicapped Children's Act of 1975) and extends the mandate of that earlier legislation to all handicapped children ages 3 to 5. In addition, P.L. 99-457 provides for early intervention services for handicapped children from birth to age 2. While the implementation of P.L. 94-142 has been conducted primarily within a traditional educational framework, the provision of services to younger children, especially to the birth to age 2 handicapped population, will require the active participation of the medical community. This paper reviews the major provisions of P.L. 99-457, discusses how the legislation will likely translate into the provision of services, and outlines some of the more immediate implications of the law for the management of children's developmental disorders by the medical community.

Differential validity of the K-ABC for lower functioning preschool children versus those of higher ability.

The Kaufman Assessment Battery for Children (K-ABC) and the Stanford-Binet Intelligence Scale, Form L-M, were administered to 93 preschool children at risk for learning problems. Lower and higher functioning groups were determined by a Stanford-Binet IQ median split. Although the Stanford-Binet and K-ABC yielded nearly identical results in the higher group, K-ABC standard scores were significantly higher than Stanford-Binet IQ in the lower group. The Stanford-Binet and K-ABC correlated more strongly in the higher group than in the lower group. These findings question the ability of the K-ABC to discriminate among at-risk preschoolers functioning in the lower ranges of cognitive ability.