Childhood blood lead screening in Arkansas: recommendations for health care providers

Multiple studies documenting regional differences in prevalence of elevated blood lead levels suggest that children are not at equal risk for lead exposure. In late 1997, the Centers for Disease Control and Prevention (CDC) published guidelines to help states and communities make decisions regarding screening practices. To apply these guidelines to Arkansas Department of Health blood lead data for the 8,883 screens completed in state fiscal year 1997, along with 1990 Census Bureau housing and poverty statistics, were compiled and reviewed. Based upon CDC criteria and other available information, conservative recommendations for blood lead screening are presented for each county in the state. Lead toxicity in children remains a significant public health concern in certain regions of the country. Between 1991-1994, it was estimated about 930,000 U.S. children one to five years old had lead levels > or = 10 micrograms/dL. Children most at risk include minorities, those residing in large central cities, and those living in poverty. Blood lead levels (BLL's) as low as 10 micrograms/dL have been linked with possible IQ deficits as well as learning and behavior problems. To date, no study has demonstrated benefit from reduction of blood lead levels in the 10-24 micrograms/dL range. Nonetheless, in 1991 the Centers for Disease Control and Prevention (CDC) published guidelines for screening and followup designed to detect lead levels this low, presumably in order to prevent additional exposure and perhaps shorten the duration of toxicity. These guidelines essentially called for universal screening of one- and two-year old children regardless of socioeconomic status or previous population-based results of lead screening in their locale. [table: see text] Since release of the controversial 1991 guidelines, several reports of lead toxicity prevalence surveys from diverse communities have demonstrated extreme variation in the magnitude of the problem. For example, in 1994 only 0.6% of Alaska Medicaid recipients six years or younger had lead levels > or = 10 micrograms/dL, with the highest being 11 micrograms/dL.

Shoulder pain in wheelchair users with tetraplegia and paraplegia

OBJECTIVE

To compare the prevalence and intensity of shoulder pain experienced during daily functional activities in individuals with tetraplegia and individuals with paraplegia who use manual wheelchairs.

DESIGN

Self-report survey.

SETTING

General community.

PARTICIPANTS

Fifty-five women and 140 men, 92 subjects with tetraplegia and 103 subjects with paraplegia who met inclusion criteria of 3 hours per week of manual wheelchair use and at least 1 year since onset of spinal cord injury.

MAIN OUTCOME MEASURES

Respondents completed a demographic and medical history questionnaire and the Wheelchair User's Shoulder Pain Index (WUSPI), a measure of pain during typical daily activities.

RESULTS

More than two thirds of the sample reported shoulder pain since beginning wheelchair use, with 59% of the subjects with tetraplegia and 42% of the subjects with paraplegia reporting current pain. Performance-corrected WUSPI scores were significantly higher in subjects with tetraplegia than in subjects with paraplegia.

CONCLUSIONS

Both the prevalence and intensity of shoulder pain was significantly higher in subjects with tetraplegia than in subjects with paraplegia. Efforts to monitor and prevent shoulder pain should continue after rehabilitation.

Alterations of the retinoic acid receptor alpha (RAR alpha) gene in myeloid and lymphoid malignancies

The retinoic acid receptor alpha (RAR alpha) protein plays a central role in myeloid differentiation, and chromosomal translocations disrupting the RAR alpha gene are implicated in the development of acute myeloid leukaemia (AML). To identify haemopoietic malignant disorders which may also be linked to RAR alpha abnormalities, Southern blot analysis was performed in DNA from 153 patients with haematological malignancies other than AML FAB type M3 using RAR alpha cDNA probes. Alterations of RAR alpha were detected in 1/42 myelodysplastic syndromes (MDS), 2/24 AML, 3/47 B-chronic lymphocytic leukaemias (B-CLL), 0/40 lymphomas and 0/60 normal individuals. These data strongly suggest that alterations of RAR alpha might predispose for myeloid and lymphoid disorders.

Haemostatic and fibrinolytic responses to bone marrow transplantation

Thrombin and plasmin activation markers were serially measured in 80 patients undergoing bone marrow transplantation (BMT). There were prothrombotic and fibrinolytic responses observed during autograft and allograft BMTs. Thrombin-antithrombin and prothrombin fragment F1+2 levels increased from day -7 to -3 (P<0.0001) from 3.7 to 7 ng/ml and 1.2 to 1.63 nmol/l, respectively. A rise in plasmin-antiplasmin levels occurred between days 4 and 14 (P< 0.0004), from 393 ng/ml on day -7 to a peak of 795 ng/ml on day 11. No correlation between reduced protein C levels post-BMT and a prothrombotic state was observed.

Age differences in lapses of intention in the Stroop task

The study evaluated the hypothesis that older adults are more susceptible to lapses of intention (lapses) than are younger adults, and explored the factors contributing to these lapses. The findings of three experiments examining the pattern of intrusion errors in the Stroop task revealed that older adults were more likely to experience lapses than were younger adults, and that lapses tended to be of longer duration in older than younger adults. Lapses were observed under conditions of suboptimal controlled attentional processing, when task conditions required the allocation of this processing in the service of multiple behavioral goals, and during periods of slowed responding. The findings of these experiments are consistent with those from a growing number of studies indicating that older adults are more susceptible to lapses of intention than younger adults.

The RAG-HMG1 complex enforces the 12/23 rule of V(D)J recombination specifically at the double-hairpin formation step

A central unanswered question concerning the initial phases of V(D)J recombination has been at which step the 12/23 rule applies. This rule, which governs which variable (V), diversity (D), and joining (J) segments are able to pair during recombination, could operate at the level of signal sequence synapsis after RAG-HMG1 complex binding, signal nicking, or signal hairpin formation. It has also been unclear whether additional proteins are required to achieve adherence to the 12/23 rule. We developed a novel system for the detailed biochemical analysis of the 12/23 rule by using an oligonucleotide-based substrate that can include two signals. Under physiologic conditions, we found that the complex of RAG1, RAG2, and HMG1 can successfully recapitulate the 12/23 rule with the same specificity as that seen intracellularly and in crude extracts. The cleavage complex can bind and nick 12x12 and 23x23 substrates as well as 12x23 substrates. However, hairpin formation occurs at both of the signals only on 12x23 substrates. Moreover, under physiologic conditions, the presence of a partner 23-bp spacer suppresses single-site hairpin formation at a 12-bp spacer and vice versa. Hence, this study illustrates that synapsis suppresses single-site reactions, thereby explaining the high physiologic ratio of paired versus unpaired V(D)J recombination events in lymphoid cells.

Productive and nonproductive complexes of Ku and DNA-dependent protein kinase at DNA termini

DNA-dependent protein kinase (DNA-PK) is the only eukaryotic protein kinase known to be specifically activated by double-stranded DNA (dsDNA) termini, accounting for its importance in repair of dsDNA breaks and its role in physiologic processes involving dsDNA breaks, such as V(D)J recombination. In this study we conducted kinase and binding analyses using DNA-PK on DNA termini of various lengths in the presence and absence of Ku. We confirmed our previous observations that DNA-PK can bind DNA termini in the absence of Ku, and we determined rate constants for binding. However, in the presence of Ku, DNA-PK can assume either a productive or a nonproductive configuration, depending on the length of the DNA terminus. For dsDNA greater than 26 bp, the productive mode is achieved and Ku increases the affinity of the DNA-PK for the Ku:DNA complex. The change in affinity is achieved by increases in both the kinetic association rate and reduction in the kinetic dissociation rate. For dsDNA smaller than 26 bp, the nonproductive mode, in which DNA-PK is bound to Ku:DNA but is inactive as a kinase, is assumed. Both the productive and nonproductive configurations are likely to be of physiologic importance, depending on the distance of the dsDNA break site to other protein complexes, such as nucleosomes.

The contribution of impaired working memory monitoring to performance of the self-ordered pointing task in normal aging and Parkinson's disease

The factors contributing to the working memory deficit observed in older adults and individuals with Parkinson's disease on the Self-Ordered Pointing Task were examined in 2 experiments. A detailed analysis of the error data revealed that errors tended to be clustered toward the end of a trial and that this effect was somewhat independent of set size. This pattern was proposed to result from a monitoring deficit where individuals failed to maintain an integrated representation of how far they had proceeded in the trial, an interpretation consistent with animal work by M. Petrides (1995).

Studies on the pharmacology of the novel histamine H3 receptor agonist Sch 50971

Experiments were performed to characterize the pharmacology of Sch 50971 ((+)-trans-4-(4(R)-methyl-3(R)-pyrolidinyl)-1H-imidazole dihydrochloride, CAS 167610-28-8), a novel histamine H3 receptor agonist. The activity of Sch 50971 was compared with that of (R)-alpha-methylhistamine (CAS 75614-87-8), a potent and moderately selective agonist of histamine H3 receptors, in a series of in vitro and in vivo assays. Sch 50971 is a high affinity, selective H3 receptor agonist in vitro and in vivo. Sch 50971 inhibits [3H]-N-alpha-methylhistamine (CAS 673-50-7) binding to the histamine H3 receptor in human brain (Ki = 5.0 nmol/l) and guinea pig brain (Ki = 2.5 nmol/l). Sch 50971 also inhibits electric field stimulated guinea pig ileum contractions (pD2 = 7.47) and decreases [3H]-norepinephrine (CAS 51-41-2) release (pD2 = 7.48) from guinea pig pulmonary artery by activation of presynaptic inhibitory H3 receptors. The in vitro effects of Sch 50971 are antagonized by low concentrations of a selective H3 antagonist, thioperamide (CAS 106243-16-7). Sch 50971 has low affinity (IC50's > 10 mumol/l) for histamine H1, dopamine D1 and D2, serotonin 5-HT2 and muscarinic cholinergic receptors. It also does not exhibit histamine H2-antagonist activity. In guinea pigs and cats, Sch 50971 exhibits in vivo H3 agonist activity. Sch 50971 inhibits sympathetic hypertension evoked by stimulation of the medulla oblongata in anesthetized guinea pigs (ED30 = 0.3 mg/kg i.v., ED30 = 1.0 mg/kg i.d.). Sch 50971 also inhibits the effects of sympathetic nerve stimulation on nasal resistance in cats. In these assays, Sch 50971 exhibits an efficacy and potency comparable to H3-agonist (R)-alpha-methylhistamine. However, under in vivo conditions, Sch 50971 does not exhibit histamine H1-mediated responses that are seen with (R)-alpha-methylhistamine at doses close to those that produce H3 effects. Therefore, Sch 50971 is a novel, potent and selective agonist of histamine H3 receptors with an improved in vitro and in vivo receptor profile selectivity compared with (R)-alpha-methylhistamine.

4-[(1H-imidazol-4-yl) methyl] benzamidines and benzylamidines: novel antagonists of the histamine H3 receptor

A series of amidine substituted phenyl-, benzyl-, and phenethylimidazoles based on the known H3 agonist SK&F 91606 (4) has been synthesized and tested as ligands for the histamine H3 receptor. Insertion of a phenyl ring between the imidazole ring and the amidine moiety produces antagonists. The benzyl series was found to be the most potent and was further investigated. Compounds 9c and 18 (entries 5 and 12, Table 1) are potent ligands for the H3 receptor with K(i) values of 16 nM and 7.2 nM respectively. In vivo, both compounds were shown to be equipotent to thioperamide (2), the standard H3 antagonist.

A randomized controlled trial of a "buddy" systems to improve success at giving up smoking in general practice

AIMS

To assess the effect on abstinence rates of pairing up smokers attending a general practice smokers, clinic to provide mutual support between clinic sessions.

DESIGN

Randomized controlled trial comparing a "buddy" condition with a "solo condition" in which smokers received the e same treatment but were not paired up.

SETTING

A general practice smokers' clinic in London.

PARTICIPANTS

One hundred and seventy-two smokers recruited by mailshot. INTERVENTION. Smokers attended a nurse-led smokers clinic 1 week prior to their quit date, on the quite date, 1 week later and 3 weeks after that. Smokers in the buddy condition were paired with another smoker trying to give up at the same time to provide mutual support between clinic sessions.

MEASUREMENT

The main outcome measure was the percentage of smokers still abstinent from cigarettes at end of treatment (weeks from quite date), verified by expired air carbon monoxide concentration.

FINDINGS

The percentage of smokers still abstinent at the end of treatment was significantly higher in the buddy condition than the solo condition (27% vs. 12%).

CONCLUSIONS

A buddy system can provide an effective element of a smoking cessation intervention at minimal cost. Further research is needed to establish the long-term efficacy of this approach and examine the effectiveness of incorporating social support into other types of smoking cessation programmes.

RAS, FMS and p53 mutations and poor clinical outcome in myelodysplasias: a 10-year follow-up

The molecular mechanisms underlying the development and evolution of myelodysplastic syndrome (MDS) are largely unknown. The increasing number of blast cells in the bone marrow correlate with poor prognosis and risk of developing acute leukemia. Such progression is frequently associated with increasing chromosomal abnormalities and genetic mutations. A cohort of 75 MDS patients were investigated for RAS, FMS and p53 mutations, and these molecular findings were related to cytogenetics, clinical status, transformation to acute leukemia, prognostic scores and survival. A mutation incidence of 57% (43/75) was found, with 48% (36/75) RAS mutations, 12% (9/75) FMS mutations and 8% (4/50) p53 mutations. The mutation status for RAS and FMS was related to MDS subgroup, increasing with poor-risk disease. The highest incidence was in the chronic myelomonocytic leukemia (CMML) subgroup. The most frequent RAS mutations were of codon 12 and a predominance of FMS codon 969 mutations was observed. A statistically significant increased frequency of transformation to AML was observed in MDS patients harboring RAS or FMS mutations (P < 0.02). Patients with oncogene mutations had a significantly poorer survival compared with those without mutations at 2 years and at the end of the period of follow-up (P < 0.02). Multivariate analysis including mutation, age, gender, diagnosis (FAB), cytogenetics and International score shows that the International score and mutation and age is the best predictive model of a poor outcome, (P < 0.0001). When the analysis was undertaken without the International score, mutation and gender was the best predictor of poor survival (P = 0.005). This study shows that oncogene mutation, indicative of genetic instability, is associated with disease progression and poor survival in MDS.

Effects of increased response dominance and contextual disintegration on the Stroop interference effect in older adults

In the study we considered the ability of the relative speed of processing-automaticity (RSOP-A) and contextual disintegration (CD) models of the Stroop interference effect to account for the age-related increase in Stroop interference typically observed in older adults. Findings from the first experiment were partially consistent with predictions of the RSOP-A model because response dominance was greater for older adults than for younger adults. However, the age-related increase in interference was independent of this increase in response dominance, suggesting that factors other than those postulated in the RSOP-A model contributed to the greater interference observed in older adults. Results of the second experiment were consistent with the CD model, which suggests that older adults had difficulty maintaining a color-naming strategy to guide task performance.

Antigen receptor gene rearrangement

Two specialized forms of site-directed double-strand (ds) DNA breakage and rejoining are part of the physiologic program of lymphocytes. One is recombination of the V, D and J gene sequences, termed V(D)J recombination, occurring during early B- and T-cell development, and the other is class-switch recombination occurring exclusively in mature B cells. For V(D)J recombination significant progress has been made recently elucidating the biochemistry of the reaction. In particular our understanding of how DNA ds breaks are both generated and rejoined has increased. For class-switch recombination no definitive information is known about the nucleases required for making the ds breaks, but recent evidence suggests that the joining phase shares activities also required for V(D)J recombination and general DNA ds break repair.

Double-blind placebo controlled trial of dextrose tablets and nicotine patch in smoking cessation

In a placebo-controlled double-blind trial 308 smokers were individually randomly allocated to one of four groups: 1) 3 g dextrose tablets and 15 mg nicotine transdermal patch; 2) dextrose and placebo patch; 3) placebo tablets and nicotine patch; 4) placebo tablets and placebo patch. Patients were scheduled to attend weekly smokers clinic sessions starting 1 week before the quit date and continue for 4 weeks after that date. The primary outcome variable was biochemically verified abstinence at the final session, four weeks after the scheduled quit date. The proportion of smokers abstinent in the four groups was as follows: 49% - dextrose plus active patch; 44% - dextrose plus placebo patch; 36% - placebo tablet plus active patch; 30% - placebo tablet plus placebo patch. The difference between the dextrose and placebo tablets (13%) was statistically significant (P < 0.01, one-tailed); the difference between the active and placebo patches (6%) was not. There was no significant difference between the effect of the dextrose when accompanied by active versus placebo patches. There was no significant effect of dextrose on weight. The results suggest that dextrose supplementation to the diet may be a cheap and simple aid to giving up smoking. Further research is now needed to establish its long-term efficacy.

Trans-4-methyl-3-imidazoyl pyrrolidine as a potent, highly selective histamine H3 receptor agonist in vivo

Extensive structural modification of immepyr (+)-2 led to the discovery of trans-4-methyl-3-imidazoyl pyrrolidine (+/-)-3a as a potent and highly selective H3 agonist. The pyrroline (+/-)-3a was resolved, and its (+) enantiomer, Sch 50971 [(+)-3a], showed a greater separation of H3 and H1 activities in vivo (H3/H1 ratio >> 330) than (R)-alpha-methylhistamine (+)-1 (H3/H1 ratio = 17), the standard H3 agonist.