Contribution of caudal brainstem to d-fenfluramine anorexia

Of the central 5-HT substrates that may mediate the anorexic actions of systemically administered d-fenfluramine (d-FEN), those in the forebrain have received the most attention. As a counterpoint to this forebrain focus, we evaluated the contribution of caudal brainstem substrates to the anorexic action of d-FEN. Two experimental protocols were employed. In one we compared the feeding response (intra-oral intake of 12.5% glucose) of intact and chronic supracollicular decerebrate (CD) rats to systemic administration of d-FEN. In the other, d-FEN was administered via fourth intracerebroventricular (ICV) injection to determine whether a dose-related suppression of intra-oral intake could be obtained. A dose-dependent suppression of intra-oral intake was obtained in the CD rat treated with d-FEN (0-8 mg/kg, delivered IP 20 min before testing). The threshold dose was two to three times higher in CD rats than in their intact controls, but the dynamic range of the dose-response curves of the two groups were overlapping with similar slopes of decline and with comparable maximal intake suppression. Fourth ICV administration of d-FEN in the intact rat yielded a dose-related suppression of intra-oral intake. Intake was also suppressed by fourth ICV d-FEN (30 mg) when rats drank 12.5% glucose solution from a spout. The reduced intra-oral intake following fourth ICV d-FEN treatment was partially attenuated by the systemic administration of the serotonin antagonist metergoline (0.4 mg/kg; IP). The CD results demonstrate the sufficiency of caudal brainstem receptors in mediating intake suppressive responses to systemic d-FEN. The fourth ICV results suggest further that 5-HT receptors in the caudal brainstem play a significant role in normal meal size control in the neurologically intact rat.

Expression of bcl-2 in lichen planus, acute graft-versus-host disease, and erythema multiforme

The bcl-2 gene family plays a significant role in the propagation of cell survival and tissue modeling. Bcl-2 was originally described in follicular lymphomas and is associated with the suppresion of cellular apoptosis. Evaluation for this protein has been performed for a variety of benign and malignant cutaneous tumors but not to any significant extent on inflammatory disorders. Therefore, we stained biopsy specimens from diseases with interface inflammation (lichen planus, acute graft-versus-host disease, and erythema multiforme) for Bcl-2. Epidermal expression of this protein was minimal for all three diseases; however, lymphocytes stained prominently in lichen planus. The data suggest that Bcl-2 is not prominently involved in the epidermal changes in these diseases. The role of other members of this oncogene family in interface dermatitis still needs to be elucidated.

Structured GP liaison for substance misuse

Changes in the fields of primary care and substance misuse have led to a need for closer liaison between drugs and alcohol services and general practice. The article describes the establishment of GP liaison posts in response to this need. It offers an account of the challenges associated with caring for people who have problems with drugs or alcohol in general practice and suggests future directions for shared care.

Multiplying health gains: the critical role of capacity-building within health promotion programs

Health outcomes in populations are the product of three factors: (1) the size of effect of the intervention; (2) the reach or penetration of an intervention into a population and (3) the sustainability of the effect. The last factor is crucial. In recent years, many health promotion workers have moved the focus of their efforts away from the immediate population group or environment of interest towards making other health workers and other organisations responsible for, and more capable of, conducting health promotion programs, maintaining those programs and initiating others. 'Capacity-building' by health promotion workers to enhance the capacity of the system to prolong and multiply health effects thus represents a 'value added' dimension to the health outcomes offered by any particular health promotion program. The value of this activity will become apparent in the long term, with methods to detect multiple types of health outcomes. But in the short term its value will be difficult to assess unless we devise specific measures to detect it. At present the term 'capacity-building' is conceptualised and assessed in different ways in the health promotion literature. Development of reliable indicators of capacity-building which could be used both in program planning and in program evaluation will need to take this into account. Such work will provide health-decision makers with information about program potential at the conclusion of the funding period, which could be factored into resource allocation decisions, in addition to the usual information about a program's impact on health outcomes. By program potential, we mean ability to reap greater and wider health gains.

Signal-detection, threshold, and dual-process models of recognition memory: ROCs and conscious recollection

Threshold- and signal-detection-based models have dominated theorizing about recognition memory. Building upon these theoretical frameworks, we have argued for a dual-process model in which conscious recollection (a threshold process) and familiarity (a signal-detection process) contribute to memory performance. In the current paper we assessed several memory models by examining the effects of levels of processing and the number of presentations on recognition memory receiver operating characteristics (ROCs). In general, when the ROCs were plotted in probability space they exhibited an inverted U shape; however, when they were plotted in z space they exhibited a U shape. An examination of the ROCs showed that the dual-process model could account for the observed ROCs, but that models based solely on either threshold or signal-detection processes failed to provide a sufficient account of the data. Furthermore, an examination of subjects' introspective reports using the remember/know procedure showed that subjects were aware of recollection and familiarity and were able to consistently report on their occurrence. The remember/know data were used to accurately predict the shapes of the ROCs, and estimates of recollection and familiarity derived from the ROC data mirrored the subjective reports of these processes.

Subjective assessment of fever by parents: comparison with measurement by noncontact tympanic thermometer and calibrated rectal glass mercury thermometer

STUDY OBJECTIVE

To assess the ability of parents to subjectively evaluate their children for fever and to compare their assessments with temperature measurements made with the use of a noncontact tympanic (NCT) or rectal glass mercury thermometer. A secondary goal was to assess how well a recently developed definition of fever for NCT thermometers, when used in the ear-equivalent mode (temperature of 37.7 degrees C or more), performed in a clinical situation.

METHODS

This 6-month prospective observational study employed a convenience sample of 180 children, aged birth to 4 years, who presented to the emergency department of a tertiary care children's hospital. Parents were asked to subjectively assess whether their child had a fever. The child's temperature was then measured with an NCT thermometer (three times in the rectal-equivalent mode and three times in the actual-ear mode). Both the subjective assessment and the NCT temperatures were compared with the rectal temperature measured by a rectal glass mercury thermometer.

RESULTS

The mean age of participants was 14.6 +/- 11.8 months (range, 2 days to 48 months); 56% were boys. The sensitivity of parental detection of fever by subjective means was 81.8% and the specificity 76.5%. The parent and the rectal glass thermometer agreed 79% of the time (95% confidence interval [CI], 73% to 85%). The sensitivity of the first temperature reading obtained with the NCT thermometer in rectal-equivalent mode was 74.7%, and the specificity was 96.3%. The NCT thermometer and the rectal glass thermometer agreed 84% of the time (95% CI, 78% to 89%). Use of the proposed definition of fever for NCT thermometers, when used in the ear-equivalent mode, caused sensitivity of a single measurement for fever to drop to 53.5%.

CONCLUSION

Parental subjective assessment of fever agreed with the presence of fever as measured by rectal glass thermometer in 79% of cases. Specificity was improved with the use of the NCT thermometer. The recently proposed definition for fever for NCT thermometers, when they are used in the ear-equivalent mode, does not appear to be validated by the current data.

beta-Amyloid induces increased release of interleukin-1 beta from lipopolysaccharide-activated human monocytes

Previous reports have demonstrated that IL-1 is elevated in the Alzheimer's disease brain. We propose that beta-amyloid (A beta) in senile plaques triggers microglial interleukin-1(IL-1) release. Since microglia and monocytes have similar lineage and functions, the human monocyte cell line, THP-1, was used to determine whether A beta peptides can stimulate release of IL-1 beta. THP-1 cells were grown in culture with LPS and incubated with various A beta peptides (0.5-10 microM). IL-1 released into the medium was measured using either an IL-1 beta ELISA or an IL-1 bioassay. Treatment of activated THP-1 cells with A beta 25-35, fibrillar A beta 1-40, or A beta 1-42 significantly elevated IL-1 beta release. A beta 25-35 with a scrambled sequence or non-fibrillar A beta 1-40 did not significantly change IL-1 beta release from activated THP-1 cells. The A beta 25-35- and fibrillar A beta 1-40 induced IL-1 beta release was dose-dependent. IL-1 released following treatment with A beta 25-35 and measured using an IL-1 bioassay gave similar results. The present report provides evidence that A beta is capable of elevating release of functional IL-1 beta, a potent pro-inflammatory cytokine, from macrophages/microglia and provides support that a chronic local inflammatory response is an ongoing phenomenon within and surrounding senile plaques.

Technical skills experiences in pediatric emergency medicine fellowship programs

Guidelines for Pediatric Emergency Medicine (PEM) fellowship programs were published by the Curriculum Subcommittee, Section of Emergency Medicine, American Academy of Pediatrics in February 1993. The guideline listed 120 technical skills that the subcommittee felt all fellows should be able to perform at the completion of their training. The purpose of this study was to measure the experience of PEM fellows in performing skills recommended by the subcommittee and to determine if documentation lists were being maintained. A written survey was mailed to 63 graduating fellows in May 1993, requesting information on the number of times procedure skills were performed. Limited experience was defined as having performed a procedure five or less times. Thirty-two surveys (51%) were returned. Eleven fellows (34%) stated they maintained a procedure documentation list. Of 117 skills analyzed, the majority of fellows had limited experience in 49 procedures and zero experience in 22 procedures. The majority of fellows had limited experience in 12 of 20 life- or limb-saving procedures and zero experience in five. Large emergency department volumes did not influence number of procedure completions. Our data indicate that graduating PEM fellows have limited experience in performing many common as well as several life- and limb-saving skills. Documentation lists of technical skills are not being maintained by most fellows.

HIV envelope-directed signaling aberrancies and cell death of CD4+ T cells in the absence of TCR co-stimulation

HIV-1 infection in CD4(+) T cells initiates a viral cytopathic effect (CPE) that is dependent on the activation of intracellular protein tyrosine kinases (PTK). PTK in T cells are also activated during the course of TCR or CD4 receptor engagement and the manner of receptor engagement may generate signals leading either to cell proliferation, tolerance induction (anergy) or programmed cell death (PCD). We have identified PTK triggered during the interaction of cells stably expressing surface HIV envelope (gp 120/gp41; HIVenv) and CD4(+)T cells, which leads to extensive and rapid individual cell death. We have found that killing is accompanied by tyrosine phosphorylation and activation of the CD4-associated p56(ICK) kinase, and by activation of a second member of the scr family of PTK, p59(fyn) kinase, normally associated with T cell stimulation through the TCR. Interestingly, in contrast with normal T cell signaling, the zeta subunit of the TCR fails to become tyrosine-phosphorylated during signaling accompanying HIV-directed cell killing. Downstream activation of the ZAP-70 PTK also does not occur. Unlike T cell apoptosis triggered by soluble HIVenv glycoproteins, which requires co-stimulation of CD4 and the antigen-specific TCR, T cell killing by membrane-associated HIVenv does not require TCR co-stimulation, because aberrant signaling and cell death are triggered by CD4(+) but TCR- cell lines. These results are the first report where dual activation of the Lck and Fyn PTK does not result in normal downstream signaling through the ZAP PTK, We suggest by analogy to SCID resulting from ZAP-70 mutations, that the dissociation of upstream PTK activation from ZAP-70 signaling contributes to T cell depletion by HIV and to the development of AIDS.

Protease-susceptible sites and properties of fragments of aortic smooth-muscle myosin

We have examined the protease susceptibility of aortic myosin, the thermal unfolding profiles of myosin rod and light meromyosin (LMM) and the solubility properties of the LMM fragments. Two major protease-susceptible sites were found, located at the head-rod junction and the heavy meromyosin (HMM)-LMM junction. Both tryptic and chymotryptic digestion of aortic myosin rod produced the LMM (80-85 kDa) and short subfragment 2 (S-2) (40-45 kDa) segments, which were similar to those of gizzard myosin rod and differed from the short LMM (70 kDa) and long S-2 (58 kDa) segments produced from skeletal-muscle rod. The thermal unfolding profile of aortic myosin rods exhibited three helix-unfolding transitions, at 47.5, 51 and 54 degrees C, similar to those of gizzard rods yet different from those of skeletal-muscle rods. There was a dramatic difference in the solubility of aortic LMM fragments of various molecular mass, as for gizzard smooth-muscle LMM and rabbit skeletal-muscle LMM. LMM fragments of molecular mass 77 kDa or more were completely insoluble in low-ionic-strength buffer, whereas LMM fragments of molecular mass 73 kDa or less were completely soluble in low-ionic-strength buffer. Proteolytic digestion patterns of LMM showed two additional protease-susceptible sites located 13 and 30 kDa from the ends of the LMM molecule. This suggests the existence of flexible regions within the LMM molecule, which may be responsible for the folded form of aortic myosin.

32P-postlabeling and HPLC separation of DNA adducts formed by diesel exhaust extracts in vitro and in mouse skin and lung after topical treatment

Diesel exhaust extracts contain many carcinogenic compounds which have been shown to form polycyclic aromatic hydrocarbon (PAH)- and nitrated PAH-DNA adducts in rodent skin and lung. The aim of this study was to characterize by 32P-postlabeling, TLC and HPLC the primary postlabeled PAH-DNA adduct(s) formed in vitro and in vivo by diesel extracts. The diesel particle extracts had known concentrations of benzo[a]pyrene, benzo[b,j,k]-fluoranthenes (B[b,j,k]F) and chrysene. DNA adducts were analyzed in calf thymus DNA incubated in vitro with PAHs activated by S9 mix and in skin and lung DNA from topically treated mice. The main diesel-derived DNA adduct formed in vitro and in vivo did not co-migrate on HPLC and large TLC plates with (+/-)-r-7,t-8-dihydroxy-t-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (anti BPDE)-, B[b]F-,B[j]F-,B[k]F-or chrysene-DNA adduct standards. By co-chromatography DNA adducts formed by chrysene from both in vitro and in vivo samples were identified. Nissan diesel extract containing higher PAH concentrations than Volkswagen automobile extract formed skin DNA adducts that co-migrated with chrysene- and anti BPDE- DNA-derived adducts. We conclude that the use of a highly sensitive 32P-postlabeling method combined with HPLC improves the identification of PAH adducts formed by complex mixtures such as diesel exhaust extracts.

Unfolding domains in smooth muscle myosin rod

Gizzard smooth muscle myosin rod, an alpha-helical coiled coil, exhibits two cooperative thermal or denaturant-induced helix unfolding transitions in solutions containing 0.6 M NaCl at neutral pH, when monitored by circular dichroism at 222 nm. The first smaller transition unfolds part of the subfragment 2 (S2) domain, and the main transition unfolds the remaining helix including the light meromyosin (LMM) domain. These unfolding domains were identified by monitoring the fluorescence of acrylodan, an environmentally sensitive fluorescence probe, and the ESR signal of a maleimide spin-label, sensitive to motion, both specifically attached to Cys 43 in the S2 region of the rod sequence. The identities of the domains were verified by studying the unfolding of the S2 and LMM coiled-coil peptides obtained by proteolytic cleavage of spin-labeled and unlabeled rod. The fluorescence of acrylodan-labeled rod indicated that although the S2 intermediate is unfolded, it is not in a random-coil conformation. The unfolded S2 region stabilized the LMM domain against unfolding, possibly by a direct interaction with the LMM region. Such an interaction may be involved in the salt- and phosphorylation-dependent 6S to 10S shift in configuration of the myosin molecule.

Biosynthetic conversion of phosphatidylglycerol to sn-1:sn-1' bis(monoacylglycerol) phosphate in a macrophage-like cell line

Bis(monoacylglycerol) phosphate has a unique stereoconfiguration of sn-glycero-1-phospho-1'-sn-glycerol and is synthesized from exogenous phosphatidylglycerol by macrophages. Previous work by our laboratory showed that the macrophage-like cell line RAW 264.7 synthesizes sn-glycero-1-phospho-1'-sn-glycerol bis(monoacylglycerol) phosphate. Here we describe studies using RAW 264.7 cells that examine the biosynthetic pathway by which bis(monoacylglycerol) phosphate is formed. Experiments were conducted using precursors that were specifically radiolabeled on the glycerol backbone in order to examine the stereoconfiguration of the intermediates and products formed in intact RAW 264.7 cells. The results of our studies indicate that a complex series of reactions are involved in the synthesis of bis(monoacylglycerol) phosphate. In this proposed pathway phosphatidylglycerol is hydrolyzed to form 1-acyllysophosphatidylglycerol which is then acylated on the headgroup glycerol to form the sn-glycero-1-phospho-1'-sn-glycerol enantiomer of bis(monoacylglycerol) phosphate. The sn-glycero-1-phospho-1'-sn-glycerol enantiomer of bis(monoacylglycerol) phosphate is then thought to undergo a stereoconversion that proceeds via the required removal of the acyl group at the sn-1 position. The resulting sn-glycero-1-phospho-1'-sn-glycerol enantiomer of lysophosphatidylglycerol with the acyl moiety on the original headgroup glycerol is then acylated to form sn-glycero-1-phospho-1'-sn-glycerol bis(monoacylglycerol) phosphate.

Molecular cloning and expression of a cDNA for human kidney cysteine conjugate beta-lyase

Kidney cysteine conjugate beta-lyase (glutamine transaminase K, kyneurenine aminotransferase, EC 2.6.1.64) metabolises the cysteine conjugates of certain halogenated alkenes and alkanes to form reactive metabolites which can produce nephrotoxicity and neurotoxicity in experimental animals and man. Using a combination of hybridisation screening and PCR techniques we have isolated a full-length cDNA for human kidney cysteine conjugate beta-lyase. Comparison of the deduced amino acid sequence with that of the rat enzyme indicated an 82% overall similarity, with 90% similarity around the pyridoxal phosphate binding site, many of the changes being conservative in nature. Expression of the cDNA in Cos-1 cells resulted in the production of a cytosolic enzyme which showed both cysteine conjugate beta-lyase and glutamine transminase K activity. Preliminary mapping of the gene for human cysteine conjugate beta-lyase by PCR analysis of genomic DNA from human-rodent hybrid cells indicated that it is located on human chromosome 9.

Use of magnetic resonance imaging and P-31 magnetic resonance spectroscopy to detect and quantify muscle dysfunction in the amyopathic and myopathic variants of dermatomyositis

OBJECTIVE

To investigate the use of magnetic resonance imaging (MRI) and P-31 magnetic resonance spectroscopy (MRS) in characterizing the metabolic and functional status of muscles in patients with amyopathic dermatomyositis (DM) and to compare the findings with those in patients with classic myopathic DM.

METHODS

Nine patients with amyopathic DM, 11 patients with myopathic DM, and 11 normal individuals were studied. MRI images of thigh muscles were obtained, and T1 and T2 relaxation times were calculated. Biochemical status was quantitated with P-31 MRS, by determining concentrations of phosphate metabolites during rest and exercise.

RESULTS

Patients with amyopathic DM showed no muscle inflammation, and MRS data obtained during rest were normal. During exercise at 25% and 50% maximum voluntary contractile force, the MRS data revealed significant differences between amyopathic DM patients and control subjects indicating inefficient metabolism. In contrast, muscles of patients with myopathic DM showed inflammation and metabolic abnormalities even during rest.

CONCLUSION

Metabolic deficiencies in patients with amyopathic DM were unmasked by exercise, suggesting that the 2 DM syndromes may share muscle abnormalities. MRI/MRS may be useful in diagnosis and optimization of treatment.

Abundance of a restricted fetal B cell repertoire in marrow transplant recipients

Patients undergoing bone marrow transplantation are humorally immunodeficient for one or more years post-transplant. This immunodeficiency could be partially caused by B cell repertoire restriction similar to that observed in ontogeny. To test this idea, the abundance of rearranged genomic segments bearing five variable heavy chain (VH) genes was compared in patients at several timepoints post-transplant and in immunologically normal neonates, infants and adults. The genes evaluated in the study (VH6, VH4-58p2, VH3-56p1, VH3-20p1 and VH3-13-2) were selected from those commonly utilized by fetal B cells. The assay employed quantitative PCR and oligonucleotide hybridization detection under conditions designed to detect relatively unmutated forms of these genes. In blood B cells from early post-transplant (2-5 months) patients, these VH genes were markedly overutilized compared with normal adults. B cells from late post-transplant (6-21 months) patients and from normal neonates and infants also overutilized these genes; however, to a lesser degree than early post-transplant B cells. The data suggest that, as in ontogeny, the B cell repertoire is strikingly restricted to fetal-type VH genes early post-transplant, and may become normal only very late (years) post-transplant.

Perceptions of collaborative practice between Navy nurses and physicians in the ICU setting

BACKGROUND: Despite strong evidence for the benefits of collaborative practice between nurses and physicians, this model remains the exception rather than the rule. OBJECTIVES: To examine the extent to which Navy nurses and physicians perceive that collaborative practice exists in the ICU, and to examine the difference in perceived use of collaborative practice by Navy nurses and physicians in the ICU. METHODS: Ninety nurses and 49 physicians working in ICUs at the Navy's four teaching hospitals and aboard the Navy's two hospital ships deployed in Southwest Asia were surveyed using the Collaborative Behavior Scale-Part I and the Collaborative Practice Scales. RESULTS: There was a significant difference between nurses' and physicians' perceptions of collaborative practice behavior. Physicians reported that collaborative practice behavior existed to a greater extent than did nurses in the study. There was no significant difference between nurses' and physicians' perceived use of collaborative practice behavior. CONCLUSIONS: Navy ICU nurses and physicians perceived that they were involved in collaborative practice behavior at a moderate level. Physicians, however, reported perceiving collaborative practice to a greater extent than did nurses. Further research, in different populations, is required to test the theorized constructs of the instruments used to measure perceptions of collaborative practice behavior in this study.

Perceptions of collaborative practice between Navy nurses and physicians in the ICU setting

BACKGROUND

Despite strong evidence for the benefits of collaborative practice between nurses and physicians, this model remains the exception rather than the rule.

OBJECTIVES

To examine the extent to which Navy nurses and physicians perceive that collaborative practice exists in the ICU, and to examine the difference in perceived use of collaborative practice by Navy nurses and physicians in the ICU.

METHODS

Ninety nurses and 49 physicians working in ICUs at the Navy's four teaching hospitals and aboard the Navy's two hospital ships deployed in Southwest Asia were surveyed using the Collaborative Behavior Scale-Part I and the Collaborative Practice Scales.

RESULTS

There was a significant difference between nurses' and physicians' perceptions of collaborative practice behavior. Physicians reported that collaborative practice behavior existed to a greater extent than did nurses in the study. There was no significant difference between nurses' and physicians' perceived use of collaborative practice behavior.

CONCLUSIONS

Navy ICU nurses and physicians perceived that they were involved in collaborative practice behavior at a moderate level. Physicians, however, reported perceiving collaborative practice to a greater extent than did nurses. Further research, in different populations, is required to test the theorized constructs of the instruments used to measure perceptions of collaborative practice behavior in this study.

Safe handling of hip replacement patients

This article aims to promote understanding of the potential causes of dislocation in post-operative hip replacements as well as the dangers of back injury to nurses handling these patients. A questionnaire survey of orthopaedic surgeons revealed where practice could be changed from the traditional 'lift only' procedure in compliance with the new EC safety regulations for manual handling.

Conformationally altered aortic myosin light chains

Aorta smooth myosin contains two types of light chain, LC20 and LC17, which fold together with the N-terminal region of each heavy chain to form the globular head region of myosin. We demonstrate an altered conformation of LC20 after its separation from heavy chain by high concentrations of urea, on the basis of the following evidence: 1) A polyclonal antibody against LC20 was not able to recognize this conformationally altered form; 2) Myosin reconstituted from heavy chains and urea-dissociated light chains exhibited extremely low ATPase activity. Circular dichroism unfolding profiles showed that light chains dissociated from heavy chains by SDS appeared to be more stable than those generated by urea dissociation.

Use of home health services by elderly persons with cognitive impairment

Individuals with cognitive impairment are at high risk for institutionalization; thus, they may benefit from the support provided by home health services. The authors studied a cohort of elderly persons admitted to a home health agency, after first assessing them for cognitive impairment. Comparisons were made between cognitively impaired and cognitively intact individuals. Significant differences in the volume and type of services used were found. Management issues for home health agencies are raised.

Use of an air medical helicopter in a trauma prevention program

Trauma is acknowledged as the leading cause of death in the United States in those under 45 years old, with the automobile being particularly lethal and costly. Preventive teaching is a component of any injury reduction program, and health care providers are becoming more actively involved in such efforts. The Mercy Air Ambulance medical team has developed a mock vehicle-collision demonstration, which is staged at area high schools shortly before graduation. The program is a joint effort of several agencies and services. It stimulates the arrest of the responsible driver, the rescue and subsequent air medical transport of two injured students and the death of a fourth student. Not only does this program educate the students in an entertaining fashion, but it results in valuable training for the multiple agencies and individuals who participate in the actual response to motor-vehicle collisions.