Perinatal choline supplementation increases the threshold for chunking in spatial memory

Chunking and perinatal choline supplementation each provide rats with alternative memory processing advantages. Evidence from radial-arm maze performance of adult (2- to 5-month-old) rats indicates that chunking of multiple food types (sunflower seeds, Noyes pellets and rice puffs) emerges for stable, differentiable baiting patterns as a function of the memory load (6, 12, 18 or 24 maze arms). The number of maze arms appeared to determine both the level of task difficulty at which rats began to implement a chunking strategy as well as when they were unable to successfully implement such a strategy due to the excess memorial demands of the task. In comparison to control rats, rats treated perinatally with choline supplementation displayed a horizontal rightward shift of the response function that related level of clustering of like-food types to the number of maze arms. These results indicate a higher threshold for implementing a chunking strategy in rats treated perinatally with choline supplementation, possibly due to a choline-induced increase in memory capacity.

Characterization of the facilitative effects of perinatal choline supplementation on timing and temporal memory

Perinatal choline supplementation can improve performance on a variety of spatial memory tasks in adulthood. In order to extend these studies, we have investigated the effects of perinatal choline supplementation on the performance of a peak-interval timing task in which a 20 s temporal criterion was trained for a visual signal in adult (3-6 months old) rats. Following 5 weeks of baseline training, rats received systemic injections of nicotine (0.1, 0.2, or 0.4 mg/kg, s.c.) or saline prior to testing on the peak-interval timing task. The results indicated that perinatal choline supplementation increased rats' sensitivity to the 20 s temporal criterion during baseline training and facilitated the clock speed enhancing effects of nicotine during drug testing. The present study extends the types of long-term cognitive enhancement produced by perinatal choline supplementation to include the temporal processing domain and relates these effects to modifications in cholinergic function.

School and community influences on adolescent alcohol and drug use

Social environment risk factors present in schools and communities have not been thoroughly investigated. This study cross-sectionally examined the social environments of schools and communities, and their influence on adolescent alcohol and drug use. Survey responses of eighth grade students (N = 2309), a random half of their parents (n = 943), community leaders (n = 118), school principals (n = 30), school counselors (n = 30) and chemical health providers (n = 14) were pooled to create indices of social environmental norms, role models, social support and opportunities for non-use of alcohol. Each index was examined for its association with prevalences from 30 schools of alcohol use onset, last-month alcohol use, heavy alcohol use and last-year marijuana use in univariate and stepwise regression analyses. Increases in the levels of norms, role models and opportunities for non-use predicted decreases in alcohol use prevalences. The explanatory power of the examined constructs in multivariate analyses was acceptably high (R2: 38-53%). These findings further support the notion that community-wide efforts need to be launched to affect changes in the normative, role model and opportunity structures of adolescents' social environments in order to curb adolescent alcohol and drug use.

Management of childhood obesity in pediatric practice

Evaluation of obese children and adolescents in the pediatric office or clinic should include baseline assessment of weight for height and body fatness; rule out endocrine and genetic causes of obesity; and evaluate other health-risk factors, such as those for cardiovascular disease, cancer, diabetes, and hypertension. Treatment of obesity is most successful if realistic goals are set; a balanced low-fat/high-fiber diet is stressed; a safe rate of weight loss of 1 to 2 pounds per week is achieved through a moderate reduction of caloric intake (approximately 20-25% decrease); increased physical activity is stressed as much as diet; parental support is strong; and behavior therapy is provided during the course of treatment to help both child and parent achieve the diet, exercise, and behavior goals.

Regulation of cadherin-mediated adhesion by the small GTP-binding protein Rho in small cell lung carcinoma cells

Metastasis is one of the most important factors responsible for the pathogenesis of small cell lung carcinoma (SCLC). SCLC cells express cadherins, which are homophilic cell-cell adhesion molecules that play an important role in the regulation of metastasis. We present the first evidence that altering the activity of the small GTP-binding protein Rho induces cadherin-mediated adhesion. ADP-ribosylation of Rho upon incubation or electroporation with recombinant C3 exoenzyme induces rapid aggregation and compaction of SCLC cells. Aggregation and compaction induced by C3 exoenzyme are diminished by removal of extracellular Ca2+ and by the HECD blocking antibody to E-cadherin but not by antibodies to other adhesion molecules. Altering the activity of Rho by ADP-ribosylation does not alter surface expression of E-cadherin, but it alters G actin content, as indicated by the binding of DNase I. Treatment with cytochalasin D also alters G actin content and increases aggregation and compaction of SCLC cells. These findings implicate Rho in the regulation of cadherin-mediated adhesion and identify Rho as a potential therapeutic target for the control of SCLC metastasis.

Inhibition of M3 muscarinic acetylcholine receptor-mediated Ca2+ influx and intracellular Ca2+ mobilization in neuroblastoma cells by the Ca2+/calmodulin-dependent protein kinase inhibitor 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-trosyl]-4-phenylpiperazin e (KN-62)

The role of Ca2+/calmodulin-dependent protein kinase (CaM kinase; EC 2.7.1.123) in the generation of Ca2+ signals by muscarinic acetylcholine receptors (mAChR) was studied. Changes in intracellular Ca2+ concentrations ([Ca2+]i) induced by mAChR activation were monitored in SK-N-SH human neuroblastoma cells using the dye Fura-2. SK-N-SH cells express M3 mAChR, as well as CaM kinase types II and IV, which are specifically inhibited by the CaM kinase antagonist KN-62 (1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazi ne). Carbamylcholine (100 microM) elicited an initial transient peak in [Ca2+]i due to mobilization of Ca2+ from internal stores, followed by a sustained elevation in [Ca2+]i that depended on the influx of extracellular Ca2+ and which was inhibited by EGTA and Ni2+. These mAChR-induced Ca2+ signals were diminished to an equal extent by preincubating the cells with 0.01 to 100 microM KN-62. KN-62 inhibited mAChR-induced Ca2+ influx and mobilization from internal stores by about 25-30%, producing a half-maximal effect at approximately 1 microM. In contrast, KN-62 (25 microM) almost completely abolished carbamylcholine-stimulated entry of divalent cations through Mn2+-permeant channels, as revealed by Mn2+ quenching of Fura-2 fluorescence. KN-62 also almost completely abolished Ca2+ influx induced by depolarization of the cells with 25 mM K+ (IC50 = 3 microM). These results suggest that CaM kinases regulate both the mobilization of intracellular Ca2+ and the stimulation of Ca2+ influx that are induced by mAChR activation, and indicate that the mAChR-induced influx of Ca2+ occurs through Ca2+ channels other than, or in addition to, the voltage-gated calcium channels or Mn2+-permeant channels which are inhibited by KN-62.

Coping and problem solving of self-mutilators

People who self-mutilate have been hypothesized to have deficient skills in coping and problem-solving that leave them vulnerable to the adoption of self-mutilation as a coping strategy. This hypothesis was tested using male incarcerated self-mutilators with comparisons being made with non-multilating, prisoner, and non-prisoner control groups. Examination of the inherent resources which enable an individual to effectively cope with stress demonstrated a depressed score for self-mutilators on the scale measuring self-worth and optimism about life. Assessment of the strategies used to cope with real problems demonstrated that self-mutilators engage in more problem avoidance behaviors. Self-mutilators also recorded less perceived control over problem-solving options. The results are discussed in terms of the effectiveness of self-mutilation as a coping strategy and the need to adopt a multidimensional approach to the investigation of coping.

Basic science of small cell lung cancer

The unique phenotype expressed by small cell lung cancer (SCLC) cells is responsible for the distinct clinical behavior of SCLC. Basic research of SCLC is aimed at identifying and characterizing the unique attributes of SCLC cells that distinguish SCLC from other forms of lung cancer and contribute to the malignant behavior of SCLC. This article summarizes recent scientific advances in this area. Specific issues which are addressed include our current understanding of how SCLC arises, the origin and consequences of the neuroendocrine phenotype expressed by SCLC cells, and the role of SCLC adhesion molecules in SCLC metastasis.

Interactions of oxytocin and vasopressin with CRF on the rat colon

Corticotropin-releasing factor (CRF), a primary mediator of stress responses, produces changes in the gastrointestinal tract identical to those induced by stress. CRF is tenfold more potent in females than in males, but gonadectomy reverses this difference. We postulated that positive modulators of CRF, such as oxytocin (OT) and vasopressin (AVP), may act in females to potentiate effects of CRF and thus could account for the gender-related differences in colonic sensitivity to CRF and stress. Given with CRF, neither OT, peripheral AVP, nor central AVP increased colonic transit any more than CRF alone, suggesting that OT and AVP do not potentiate CRF's actions in the colon. These data indicate that endogenous OT and AVP do not directly affect colonic transit, and that OT and AVP do not account for the gender-related differences in the effects of stress and CRF on colonic transit.

Morphine tolerance and dependence in the rat intestine in vivo

There has been no previous demonstration of opioid tolerance and dependence with respect to the propulsive and contractile activities of the gut in vivo. In the experiments described herein, morphine was administered continuously (1 mg/kg/hr s.c., 72 hr) and/or by bolus injection (2 mg/kg) and intestinal motility and transit were evaluated in unanesthetized rats. Tolerance in intestinal motility (contractions) and propulsion (transit) was measured in two ways, i.e., by measuring the time required for motility and propulsion to return to control values and by measuring the loss of effectiveness of bolus morphine administered to animals receiving continuous infusion of the opiate. The dose of morphine chosen for continuous administration (1 mg/kg/hr s.c. via Alzet minipumps) was based on the dose at which morphine inhibited intestinal propulsion by 50%. Morphine (1 mg/kg/hr) decreased the frequency of contractions in, and propulsion along, the small bowel and colon and produced mild antinociception. The frequency of duodenal and colonic contractions returned to normal within 13 to 16 hr. After 24 hr of morphine treatment, the inhibitory effects of bolus doses of morphine on motility and transit were diminished; the effects were eventually lost (48 hr). Similarly, the antinociceptive effects of bolus doses of morphine were diminished by 18 hr and lost by 24 hr. Naloxone (0.1 mg/kg s.c.) given to morphine-tolerant animals (72 hr) resulted in an increase in the frequency and amplitude of contractions in the colon, an increase in the propulsive activity of the small intestine and colon and diarrhea. These results provide direct demonstration of opioid tolerance and dependence of contractile and propulsive activity in the rat intestine in vivo.

Cholecystokinin-induced antinociception is not blocked by CCK-A or CCK-B receptor antagonists

To determine the relative importance of CCK-A, CCK-B, and opioid receptors in mediating the antinociceptive actions of cholecystokinin, we evaluated the actions of selective agonists and antagonists in the mouse hot plate assay. The agonists used were CCK (1-30 nmol i.c.v.), a CCK-A receptor agonist (SNF9019; 0.3-10 nmol i.c.v.), and a CCK-B receptor agonist (SNF9007; 0.3-10 nmol i.c.v.). The antagonists used were the CCK-A receptor antagonist, L364,718 (12.5 nmol i.c.v.), CCK-B receptor antagonist, L365,260 (2.5-25 nmol i.c.v.), and the nonselective opioid receptor antagonist naloxone (1 mg/kg s.c.). CCK and its receptor-selective analogues, SNF9019 and SNF9007, resulted in antinociception that was blocked by naloxone, but was not antagonized by L364,718 or L365,260. In contrast, in positive control experiments, the inhibitory effects of CCK, SNF9019, and SNF9007 on gastrointestinal propulsion in mice were antagonized by identical i.c.v. doses of L364,718 and L365,260. We conclude that centrally administered CCK produces antinociception in the mouse hot plate assay via opioid receptors, but independent of CCK-A or CCK-B receptors. It is necessary to speculate that other CCK receptors, not antagonized by currently available selective antagonists, may exist.

Peer-planned social activities for preventing alcohol use among young adolescents

The Project Northland peer participation program tested the feasibility of involving students in the planning and promotion of alcohol-free social activities for their peers and to determine whether such participation was associated with reduced alcohol use. The peer program was offered in 20 northeastern Minnesota schools when the study cohort was in seventh grade; students completed a survey in the beginning of sixth grade and at the end of sixth grade and seventh grade. Nearly 50% of the study cohort participated in the program. At the end of seventh grade, after controlling for confounders, an association was observed between student involvement with planning activities and a lower rate of alcohol use. This association was strongest among students who had reported alcohol use at the beginning of sixth grade. This cohort study suggests adolescent involvement in planning their own alcohol-free activities may be an efficacious strategy to prevent or reduce the prevalence of alcohol use among youth. Future studies are warranted to evaluate this association using experimental research designs.

Effects of ethanol and cocaethylene on cocaine pharmacokinetics in conscious dogs

Coingestion of cocaine and ethanol is common among cocaine users, and this combination is reported to enhance the euphoric effects of cocaine. The cardiovascular effects of cocaine are increased in the presence of ethanol, although the mechanism(s) involved in this interaction are poorly understood. Recent studies suggest the enhanced cardiac effects may be caused by ethanol-mediated inhibition of cocaine metabolism leading to higher cocaine plasma concentrations. However, these studies were all performed in animals or humans that form cocaethylene when ethanol and cocaine are coadministered. Thus, it is also possible that cocaethylene could inhibit cocaine's metabolism. Preliminary studies in our laboratory indicate the dog does not form detectable quantities of cocaethylene after coadministration of cocaine and intravenous ethanol. Thus, the dog may be a useful model for isolating the individual contributions of ethanol and cocaethylene to this interaction. The purpose of the present study was to confirm this observation, and to determine the effects of ethanol and cocaethylene on cocaine pharmacokinetics in the conscious dog. Six dogs received cocaine (3 mg/kg i.v.) alone, ethanol (1 g/kg i.v.) followed by cocaine (3 mg/kg i.v.), and cocaine (3 mg/kg i.v.) + cocaethylene (3 mg/kg i.v.). Cocaethylene was not detected in any of the plasma samples from the six dogs after administration of cocaine and ethanol. Ethanol and cocaethylene reduced mean cocaine clearance by 47% and 26%, respectively. Inhibition of cocaine's metabolism by both ethanol and cocaethylene may play an important role in mediating the enhanced effects of cocaine in the presence of ethanol.

Project Northland: outcomes of a communitywide alcohol use prevention program during early adolescence

OBJECTIVES

Project Northland is an efficacy trial with the goal of preventing or reducing alcohol use among young adolescents by using a multilevel, communitywide approach.

METHODS

Conducted in 24 school districts and adjacent communities in northeastern Minnesota since 1991, the intervention targets the class of 1998 (sixth-grade students in 1991) and has been implemented for 3 school years (1991 to 1994). The intervention consists of social-behavioral curricula in schools, peer leadership, parental involvement/education, and communitywide task force activities. Annual surveys of the class of 1998 measure alcohol use, tobacco use, and psychosocial factors.

RESULTS

At the end of 3 years, students in the intervention school districts report less onset and prevalence of alcohol use than students in the reference districts. The differences were particularly notable among those who were nonusers at baseline.

CONCLUSIONS

The results of Project Northland suggest that multilevel, targeted prevention programs for young adolescents are effective in reducing alcohol use.

Quantitation of cocaine and cocaethylene in canine serum by high-performance liquid chromatography

A reversed-phase high-performance liquid chromatographic procedure for the determination of cocaine and cocaethylene in canine serum has been developed. The compounds were extracted from 1 ml of alkalinized canine serum with hexane. Chromatographic separation was achieved with a cyanopropyl column (250 x 4.6 mm I.D., 5 microns) using a mobile phase of acetonitrile and phosphate buffer, pH 7.40 (38:62, v/v) flowing at 1 ml/min. Eluate was monitored by a variable-wavelength UV detector set to 230 nm. The extraction procedure yields an average recovery of 99 and 96% for cocaine and cocaethylene, respectively. The between-day coefficients of variation, at 2400 ng/ml, for cocaine and cocaethylene were both 8.6% and the within-day coefficients of variation, at 400 ng/ml, for cocaine and cocaethylene were 7.3 and 8.0%, respectively. A concentration-time profile resulting from administration of 3 mg/kg cocaine and cocaethylene to the dog revealed a similar disposition between cocaine and cocaethylene, with a clearance and volume of distribution at steady-state values of 72.8 and 61.0 ml/min/kg and 2.6 and 2.7 1/kg, respectively.

Expression of Ca2+/calmodulin-dependent protein kinase types II and IV, and reduced DNA synthesis due to the Ca2+/calmodulin-dependent protein kinase inhibitor KN-62 (1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenyl piperazine) in small cell lung carcinoma

Because changes in intracellular Ca2+ affect progression through the mitotic cell cycle, we investigated the role of Ca2+-binding proteins in regulating cell cycle progression. Evidence was found demonstrating that the activation of Ca2+/calmodulin-dependent protein kinase (CaM kinase) inhibits cell cycle progression in small cell lung carcinoma (SCLC) cells. We also demonstrated that SCLC cells express both CaM kinase type II (CaMKII) and CaM kinase type IV (CaMKIV). Five independent SCLC cell lines expressed proteins reactive with antibody to the CaMKII beta subunit, but none expressed detectable proteins reactive with antibody to the CaMKII alpha subunit. All SCLC cell lines tested expressed both the alpha and beta isoforms of CaMKIV. Immunoprecipitation of CaMKII from SCLC cells yielded multiple proteins that autophosphorylated in the presence of Ca2+ / calmodulin. Autophosphorylation was inhibited by the CaMKII(281-302) peptide, which corresponds to the CaMKII autoinhibitory domain, and by 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4- phenylpiperazine (KN-62), a specific CaM kinase antagonist. Influx of Ca2+ through voltage-gated Ca2+ channels stimulated phosphorylation of CaMKII in SCLC cells, and this was inhibited by KN-62. Incubation of SCLC cells of KN-62 potently inhibited DNA synthesis, and slowed progression through S phase. Similar anti-proliferative effects of KN-62 occurred in SK-N-SH human neuroblastoma cells, which express both CaMKII and CaMKIV, and in K562 human chronic myelogenous leukemia cells, which express CaMKII but not CaMKIV. The expression of both CaMKII and CaMKIV by SCLC cells, and the sensitivity of these cells to the anti-proliferative effects of KN-62, suggest a role for CaM kinase in regulating SCLC proliferation.

Peripheral post-training administration of 4-OH amphetamine enhances retention of a reduction in reward magnitude

This experiment examined the effect of post-training systemic (sc) injections of 4-OH amphetamine on memory for a reduction in reward. Rats were trained to run in a straight alley (six trials per day, 30-s intertrial interval) and received either 1 or 10 45-mg sucrose pellets on each trial. On Day 8, rats receiving 10 pellets were shifted to the 1-pellet reward. Shifted rats displayed a characteristic increase in response latencies typically attributed to an aversive emotional response to reward reduction. Immediately after the reward shift, all rats received an injection of either 2 mg/kg of 4-OH amphetamine or the equivalent volume of physiological saline. The rats were then returned to their home cages for 6 days without further training. On Day 15 the rats were returned to training, all with 1 sucrose pellet as reward. The performance of unshifted rats was comparable to that on Day 8 and the first trial performance of shifted rats given post-training saline was not significantly different from that of unshifted rats. Further, the shifted saline group's mean latencies for the entire training block on Day 15 were comparable to their mean latencies on Day 8. These findings suggest that the shifted saline rats did not remember the prior reward reduction on Day 8. In contrast, the shifted rats given post-training 4-OH amphetamine displayed first trial latencies that were longer than those of all other groups on Day 15. Additionally, on the entire training block on Day 15 the latencies of the shifted 4-OH amphetamine group were longer than those recorded on Day 8, indicating that shifted 4-OH amphetamine rates retained memory of the prior reward reduction. These findings suggest that post-training activation of peripheral adrenergic systems by 4-OH amphetamine enhances the retention for aversive emotional consequences elicited by reward reduction.

Inhibition of adenylyl cyclase activity by the cholecystokinin analog SNF 9007 in neuroblastoma x glioma NG108-15 hybrid cells

The effect of the cholecystokininB (CCKB) receptor-selective cholecystokinin octapeptide (CCK-8) analog SNF 9007 on forskolin-stimulated adenylyl cyclase activity in NG108-15 hybrid cells was measured. The activity of SNF 9007 was compared to the delta opioid agonists D-Pen2-D-Pen5-enkephalin (DPDPE, delta 1 receptor-selective) and Tyr-D-Ala-Phe-Glu-Val-Val-Gly-NH2, (D-Ala2-deltorphin II, delta 2-receptor-selective) because SNF 9007 binds with moderate affinity to delta opioid receptors. SNF 9007 inhibited forskolin-stimulated adenylyl cyclase activity with efficacy similar to DPDPE. IC50 determinations showed that D-Ala2-deltorphin II was the most potent, followed by DPDPE, then SNF 9007 (IC50 values = 0.013, 0.21 and 4.8 microM, respectively). CCK-8 had no effect on adenylyl cyclase activity. The delta 1 receptor-selective antagonist 7-benzylidenenaltrexone hydrochloride (BNTX, 10 nM) had no effect on the activity of any of these agonists, but the delta 2 receptor-selective antagonist naltriben methanesulfonate (NTB, 10 nM) increased IC50 values of all the agonists. Combinations of BNTX and NTB (10 nM each) increased the D-Ala2-deltorphin II IC50 value 12-fold, the DPDPE IC50 value 18-fold and the SNF 9007 IC50 value 26-fold. The effect of the combined delta antagonists on SNF 9007 activity was different from the effect on DPDPE or D-Ala2-deltorphin II activity. These data suggest that the interaction of the CCK-8 analog SNF 9007 with opioid receptors in NG108-15 hybrid cells is different from the interaction of opioid peptides with these receptors.

Fear of AIDS and homophobia: implications for direct practice and advocacy

Studies of health care trainees and professionals have demonstrated that their level of empathy and caring is negatively affected by the knowledge that the person being treated is homosexual, in part because of stigma associated with HIV infection and AIDS. The survey discussed in this article examined the relationship between homophobia and the fear of AIDS within the context of several categorical questions. Gender differences in attitudes were also examined. Respondents who more liberally endorsed rights for gay men and lesbians were less homophobic and had less fear of AIDS. Suggestions are made for sensitizing social workers to the inhibitory effects of homophobia and fear of AIDS when working with HIV-infected clients or people in the gay community.

Helicobacter pylori utilises urea for amino acid synthesis

Helicobacter pylori has one of the highest urease activities of all known bacteria. Its enzymatic production of ammonia protects the organism from acid damage by gastric juice. The possibility that the urease activity allows the bacterium to utilise urea as a nitrogen source for the synthesis of amino acids was investigated. H. pylori (NCTC 11638) was incubated with 50 mM urea, enriched to 5 atom% excess 15N, that is the excess enrichment of 15N above the normal background, in the presence of either NaCl pH 6.0, or 0.2M citrate pH 6.0. E. coli (NCTC 9001) was used as a urease-negative control. 15N enrichment was detected by isotope ratio mass spectrometry. H. pylori showed intracellular incorporation of 15N in the presence of citrate buffer pH 6.0 but there was no significant incorporation of 15N in unbuffered saline or by E. coli in either pH 6.0 citrate buffer or unbuffered saline. The intracellular fate of the urea-nitrogen was determined by means of gas chromatography/mass spectrometry following incubation with 15N enriched 5 mM urea in the presence of either 0.2 M citrate buffer pH 6.0 or 0.2 M acetate buffer pH 6.0. After 5 min incubation in either buffer the 15N label appeared in glutamate, glutamine, phenylalanine, aspartate and alanine. It appears, therefore, that at pH and urea concentrations typical of the gastric mucosal surface, H. pylori utilises exogenous urea as a nitrogen source for amino acid synthesis. The ammonia produced by H. pylori urease activity thus facilitates the organism's nitrogen metabolism at neutral pH as well as protecting it from acid damage at low pH.

Inhibition of voltage-gated Ca2+ channel activity in small cell lung carcinoma by the Ca2+/calmodulin-dependent protein kinase inhibitor KN-62 (1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperaz ine)

Although small cell lung carcinoma (SCLC) cells express both voltage-gated Ca2+ channels (VGCC) and second messenger-operated Ca2+ channels (SMOCC), little is known about the factors that regulate the activity of these channels in SCLC cells. Ca2+/calmodulin-dependent protein kinase (CaM kinase) type II has been implicated recently in regulating Ca2+ channel activity in other cell types. Because of this, we investigated the effects of the specific CaM kinase antagonist 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-L-tryosyl] -4-phenylpiperazine [sequence: see text] (KN-62) on Ca2+ channel activity in SCLC cells. Incubation with 10 microM KN-62 for 20 min inhibited depolarization-dependent 45Ca2+ influx by 96.1 +/- 2.1% in four independent SCLC cell lines, and by 42.2 +/- 6.8% in the NCI-H146 SCLC cell line. Similar inhibitory effects of KN-62 were observed when Fura-2 was used to measure depolarization-dependent Ca2+ influx. These results indicate that KN-62 potently inhibits VGCC activity in SCLC cells. In contrast, KN-62 (10 microM, 20 min) did not inhibit significantly Ca2+ mobilization induced by muscarinic acetylcholine receptor (mAChR) activation in SCLC cells. This indicates that SMOCC are less susceptible than VGCC to inhibition by KN-62 in SCLC cells. Because mAChR activation also inhibits VGCC activity in SCLC cells, we examined the effects of KN-62 on the mAChR-mediated inhibition of VGCC activity. To do this, we measured depolarization-dependent 45Ca2+ influx in SCLC cells incubated with submaximal concentrations of KN-62 and the mAChR agonist carbachol. Treatment of cells with both drugs resulted in almost twice as much inhibition of VGCC activity as in cells treated with only one of the drugs. This indicates that inactivation of CaM kinase with KN-62 does not suppress the ability of mAChR agonists to inhibit VGCC activity.

Detecting Fake-Bad MMPI-A Profiles

This study examined the extent to which the validity scales of the Minnesota Multiphasic Personality Inventory-Adolescent (MMPI-A; Butcher et al., 1992) could identify adolescents who were faking-bad. This study also examined the extent to which the validity scales could differentiate between nonclinical adolescents instructed to fake-bad and both clinical and nonclinical adolescents who received standard instructions. Participants were 58 male and 80 female high school students and 58 male and 80 female adolescents from clinical settings. Results indicated that the mean profiles resembled those previously reported for adults on the MMPI (Graham, 1987) and MMPI-2 (Graham, Watts, & Timbrook, 1991) and for adolescents on the original MMPI (Archer, Gordon, & Kirchner, 1987). Accurate identification of students who were faking-bad was achieved. It was possible to differentiate between the clinical adolescents and nonclinical adolescents who were faking, and it was possible to differentiate between nonclinical adolescents who were faking and nonclinical adolescents with standard instructions; however, different cutoff scores were needed for these two discriminations. Optimal cutoff scores were presented.

Is a high-fiber diet safe for children?

OBJECTIVES

Although dietary fiber is associated with important health benefits in childhood, there have been concerns that very high fiber diets may result in adverse health effects. This report reviews the major safety concerns associated with consumption of very high fiber diets, estimates the amount of fiber that may cause adverse physiologic effects in children, and proposes safe levels of dietary fiber intake for children and adolescents.

METHODS

Published studies on dietary fiber intake in childhood were reviewed to determine major safety concerns, to document adverse effects, to characterize subjects involved and the dose and type of fiber consumed, and to estimate potential relevance to US children and adolescents. Levels of dietary fiber reported to have adverse health effects were compared with recommended levels of fiber intake for children older than 2 years of age.

RESULTS AND CONCLUSIONS

A review of the scientific literature suggests that a small loss of energy, protein, and fat may occur with a high intake of dietary fiber. However, this small loss of energy is unlikely to be significant to children consuming adequate levels of major nutrients, especially at conservative fiber intakes as recommended by the American Health Foundation's age plus 5 formula. In addition, it is estimated that even with a doubling of current dietary fiber, there is unlikely to be an adverse effect on serum vitamin and mineral concentrations in healthy US children consuming a balanced diet containing adequate levels of nutrients. Thus, evidence suggests that for US children, a moderate increase in dietary fiber is more likely to be healthful than harmful.