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Biomedical subjects

R M Johnson

Publications and source records attributed to R M Johnson.

At least 19 recordsLinked to original sources
PubMed2006

A deficit of detoxification enzymes: pesticide sensitivity and environmental response in the honeybee.

The honeybee genome has substantially fewer protein coding genes ( approximately 11 000 genes) than Drosophila melanogaster ( approximately 13 500) and Anopheles gambiae ( approximately 14 000). Some of the most marked differences occur in three superfamilies encoding xenobiotic detoxifying enzymes. Specifically there are only about half as many glutathione-S-transferases (GSTs), cytochrome P450 monooxygenases (P450s) and carboxyl/cholinesterases (CCEs) in the honeybee. This includes 10-fold or greater shortfalls in the numbers of Delta and Epsilon GSTs and CYP4 P450s, members of which clades have been recurrently associated with insecticide resistance in other species. These shortfalls may contribute to the sensitivity of the honeybee to insecticides. On the other hand there are some recent radiations in CYP6, CYP9 and certain CCE clades in A. mellifera that could be associated with the evolution of the hormonal and chemosensory processes underpinning its highly organized eusociality.

Adaptation, Physiological↗
PubMed2004

Toxicity and cerebrospinal fluid levels of carboplatin chronically infused into the brainstem of a primate.

PURPOSE: Carboplatin was infused into the brainstem of cynomolgus monkeys to investigate neurotoxicity and systemic exposures following chronic local delivery. METHODS: Infusions at 0.42 microl/h were intended to deliver 0.025 (n = 2), 0.075 (n = 3), 0.25 (n = 5), and 0.75 (n = 3) mg/kg by day 30. Laboratory tests, radiographic measurements, and clinical observations were used to monitor toxicity. Blood and cerebrospinal fluid (CSF) were sampled for platinum. RESULTS: Lethargy and ataxia were observed after week 4 in the monkeys given 0.075 mg/kg, and week 2 in the monkeys given 0.25 mg/kg when the infused doses were approximately 250 and 400 microg, respectively. Rapidly progressive neurotoxicity with the 0.75 mg/kg dose required termination of the infusions at days 4-10. Hematology and chemistry values were unremarkable in all groups. Blood levels of platinum remained undetectable in 0.025 and 0.075 mg/kg dose groups. Levels in the 0.25 mg/kg group were 3.1 +/- 0.6 microg/l at 2 weeks and 5.2 +/- 0.8 microg/l at 1 month. The CSF platinum levels varied. Animals in the 0.25 mg/kg group had higher CSF levels at 2 weeks (avg. 65 microg/l, range 36-89) compared to their 1 month value (avg. 60 microg/l, range 7-170), despite the constant infusion. CONCLUSION: Carboplatin can be chronically infused into monkey brainstems. Neurotoxicity is the predominant side effect and is dose-dependent. Pharmacokinetics of local and systemic delivery are different for carboplatin. Further studies are needed to monitor toxicity at higher flow rates and to investigate drug binding to abnormal central nervous system (CNS) tissues.

Animals↗
PubMed2003

Review of evaluations of educational approaches to promote safe storage of firearms.

OBJECTIVE: To systematically review evaluation studies of educational interventions promoting safe firearm storage. METHODS: Medline, ERIC, PsycINFO, Criminal Justice Periodicals Index, Cumulative Index of Nursing and Allied Health Literature, and Sociofile were searched. The references from each potentially eligible study were checked, and experts in the field were contacted for additional reports. In addition, an internet search was performed to identify programs not published in the conventional literature. Sources relevant to safe firearm storage promotion were selected and evaluated. RESULTS: Seven studies met inclusion criteria: adult subjects, program description was included, and firearm storage outcomes were measured. One was a randomized controlled trial and the other six were one group pre-test and/or post-test. The studies were classified into the following categories based on the intervention strategies used: (1). counseling and firearm safety materials (n=3); (2). counseling/educational message (n=3); and (3). firearm safety materials distribution (n=1). The outcomes were safe firearms storage (firearms locked up and unloaded or removal from home) after intervention. Four studies, three using counseling and materials distribution, reported improved storage after the interventions. CONCLUSIONS: It is not yet clear what types of interventions, or which specific intervention components, prompt gun owners to securely store their weapons. Increased understanding of gun storage behaviors and stronger evaluation designs will aid further understanding of this important issue.

Adult↗
PubMed2001

Kawasaki-like syndromes associated with human immunodeficiency virus infection.

Kawasaki disease is an acute febrile vasculitic syndrome of early childhood. It is very rarely seen in adults. Among the adult patients with Kawasaki disease who have been described, a disproportionate number are infected with human immunodeficiency virus (HIV). This suggests that the immunocompromised state may predispose individuals to this syndrome. We report our experience with 2 HIV-positive patients who presented with Kawasaki-like syndromes and review the published literature on HIV-positive patients with similar syndromes.

Adult↗
PubMed2001

"Love our kids, lock your guns": a community-based firearm safety counseling and gun lock distribution program.

BACKGROUND: Safer storage practices may reduce injury rates by limiting youth access to firearms. OBJECTIVE: To determine if a firearm safety counseling and gun lock distribution program improved storage practices. DESIGN: Community-based before-after trial. SETTING: Urban county in central North Carolina. PARTICIPANTS: One hundred twelve adult gun owners recruited through a mass media advertising campaign. INTERVENTION: In the parking lot of a shopping mall, participants completed a survey, and were then provided with tailored counseling, gun safety information, a gun lock, and instructions to use it. MAIN OUTCOME MEASURES: Firearm storage practices, assessed by survey and personal interview (baseline) and telephone interview (6-month follow-up). RESULTS: Most participants were white (62%), men (63%), had children (58%), and owned a gun for protection (74%). At follow-up, of the 82 participants, 63 (77%) (up from 39 [48%]) reported storing their gun(s) in a locked compartment (P =.004), 59 (72%) (up from 0) reported using gun locks (P =.001), 61 (74%) (up from 57 [69%]) reported storing their ammunition locked in a separate location, 59 (72%) (up from 52 [63%]) reported storing their gun(s) unloaded, and 6 (7%) (down from 15 [18%]) reported storing firearms unlocked and loaded. Participants with children were more likely at baseline to store weapons unlocked and loaded (38 [59%] vs 19 [41%]; P =.02) but were more likely after counseling to lock their weapons (29 [58%] vs 14 [44%]) and remove guns from the home (5 [10%] vs 0 [0%]). CONCLUSIONS: This program prompted reporting of safer firearm storage practices, particularly among parents. Longer follow-up, verification of self-reports and correct use, testing of gun locks, and monitoring firearm injury rates after distribution programs are needed to establish the public health potential of this approach.

Adult↗
PubMed2001

Facial fractures in a level I trauma centre: the importance of protective devices and alcohol abuse.

Urban trauma centres have recently noted a shift in the causative mechanism of facial fractures away from motor vehicle crashes (MVC) to blunt assaults (BA). This study was conducted to examine the incidence and aetiology of facial fractures at our institution as well as the relationship with alcohol and protective device use. Trauma registry records of all patients admitted to a level I trauma centre from 1 January 1988 to 1 January 1999 were reviewed. There were 13594 trauma admissions during the 11-year period. Facial fractures were sustained by 1429 patients (10.5%) and this group forms the subject of this study. MVC was the predominant aetiology (59.9%) followed by BA (18.8%). Facial fractures were found in 9.5% of restrained MVC patients compared to 15.4% of unrestrained patients (P<0.00l). Non-helmeted motorcyclists were four times more likely to sustain facial fractures (4.3% vs. 18.4%) than helmeted patients (P<0.00l). 39.6% of patients in the MVC group were legally intoxicated compared to 73.5% in the BA group (P<0.00l). 45.4% of unrestrained patients with facial fractures were intoxicated compared to 11.8% of restrained MVC patients with facial fractures (P<0.001). MVC continue to be the primary aetiology of facial fractures in our trauma population. Protective devices decrease the incidence of facial fractures. Lack of protective device use and the consumption of alcohol correlate with sustaining facial fractures.

Accidents, Traffic↗
PubMed2001

Firearm storage practices of officers in a law enforcement agency in the South.

BACKGROUND: Law enforcement officers play an important role in promoting firearm safety. This study examined their firearm-related attitudes and practices. METHODS: We conducted an anonymous, self-administered survey of law enforcement officers in an agency in the South concerning firearm ownership, storage practices, and opinions. RESULTS: The 207 respondents (response rate=71%) were primarily white (60%) and male (89%). The proportions of respondents with (55%) and without (45%) children were similar. Eighty percent of the officers had firearms in addition to the one they were issued for work. Most stored firearms unlocked (59%) and loaded (68%); almost half (44%) reported storing firearms both unlocked and loaded. Eighty-five percent indicated that they felt an added need to protect themselves and family because of their job. Those who reported having firearms for self-protection were less likely than those who had firearms for recreation to store firearms securely. As compared to those without children, law enforcement officers with children were more likely to store firearms safely, and were especially likely to store firearms locked up (chi(2)=12.72, p<0.0001). Respondents favored background checks, mandatory safety training, and enforcement of storage laws. Three quarters approved of government safety regulations for handguns. CONCLUSIONS: Despite the law enforcement officers' prominent role in firearm safety promotion and support for initiatives that limit unauthorized access, our study found that many do not practice safe storage. Apparently, many officers keep their firearms stored unlocked and loaded for the purpose of protecting themselves and their families. Addressing concerns about personal safety is a necessary step in promoting safe storage to law enforcement officers.

Adult↗
PubMed2001

Law enforcement officers' opinions about gun locks: anchors on life jackets?

OBJECTIVES: One way law enforcement officers support firearm safety is by promoting the use of gun locks. This investigation examined law enforcement officers' willingness to use gun locks on their own guns, as well as their opinions regarding gun locks in general. SETTING: Law enforcement officers from an urban agency in the southern region of the United States. METHODS: Free keyed cable gun locks were distributed to all law enforcement officers in one agency who wanted one, and then an anonymous questionnaire survey was conducted about their subsequent use of, and attitudes toward, these devices. RESULTS: About half of the 207 officers collected gun locks (n=103). Nearly three quarters (73%) completed and returned the questionnaire. Two thirds reported that they were not using the gun lock they collected (65%), and over half disagreed that gun lock use should be required (56%). Very few cited any actual or potential technical problems with the device. An important reason given for non-use of gun locks related to being able to access the weapon quickly in case of an emergency. CONCLUSIONS: The findings highlight the need for further investigation into law enforcement officers' attitudes toward gun locks, the degree to which their attitudes affect their firearm safety counseling, and the need to develop a gun safety device that can be disengaged quickly.

Adult↗
PubMed2000

Humans and old world monkeys have similar patterns of fetal globin expression.

The expression of epsilon- and gamma-globin mRNA and protein has been determined in three Old World monkey species (Macaca mulatta, Macaca nemestrina, and Cercopithecus aethiops). Using RT-PCR with primers for epsilon- and gamma-globin, both mRNAs were detected in early fetal stages, whereas at 128 days (85% of full term), only gamma was expressed. High-performance liquid chromatography was used for separation and quantitation, and matrix-assisted laser desorption/ionization mass spectrometry was used for identification of globin polypeptides. An alpha-globin polymorphism was observed in all of the species examined. During fetal life, gamma-globin was the predominant expressed beta-type globin. The red blood cells of infants still contained substantial amounts of gamma-globin, which declined to negligible levels in 14 weeks as beta-globin expression reached adult values. The ratio of gamma1- to gamma2-globins (equivalent to Ggamma/Agamma in humans) was approximately 2.5, similar to the Ggamma/Agamma ratio observed in humans. Thus, gamma-globin gene expression in these Old World monkeys species has three features in common with human expression: expression of both duplicated gamma genes, the relative preponderance of gamma1 over gamma2 expression, and the delay of the switch from gamma- to beta-globin until the perinatal period. Thus, the catarrhines seem to share a common pattern of developmental switching in the beta-globin gene cluster, which is distinct from the timing of expression in either prosimians or the New World monkeys. Our results indicate that an Old World monkey, such as Rhesus, could serve as a model organism (resembling humans) for experimentally investigating globin gene expression patterns during the embryonic, fetal, and postnatal stages.

Animals↗
PubMed2000

Red cells from glutathione peroxidase-1-deficient mice have nearly normal defenses against exogenous peroxides.

The role of glutathione peroxidase in red cell anti-oxidant defense was examined using erythrocytes from mice with a genetically engineered disruption of the glutathione peroxidase-1 (GSHPx-1) gene. Because GSHPx-1 is the sole glutathione peroxidase in the erythrocyte, all red cell GSH peroxidase activity was eliminated. Oxidation of hemoglobin and membrane lipids, using the cis-parinaric acid assay, was determined during oxidant challenge from cumene hydroperoxide and H(2)O(2). No difference was detected between wild-type red cells and GSHPx-1-deficient cells, even at high H(2)O(2) exposures. Thus, GSHPx-1 appears to play little or no role in the defense of the erythrocyte against exposure to peroxide. Simultaneous exposure to an H(2)O(2) flux and the catalase inhibitor 3-amino-1,2,4-triazole supported this conclusion. Hemoglobin oxidation occurred only when catalase was depleted. Circulating erythrocytes from the GSHPx-1-deficient mice exhibited a slight reduction in membrane thiols, indicating that high exposure to peroxides might occur naturally in the circulation. (Blood. 2000;96:1985-1988)

Animals↗
PubMed2000

Evidence for leptin expression in fishes.

Tissues from bony fish were screened with anti-mouse leptin antibodies to detect the presence of the fat-regulating hormone in fishes. Low molecular-weight (16 kDa) immunoreactive bands were detected in blood, brain, heart and liver of green sunfish (Lepomis cyanellus), bluegill sunfish (Lepomis macrochirus), largemouth bass (Micropterus salmoides), white crappie (Pomonix annularis), channel catfish (Ictalurus punctatus), and rainbow trout (Oncorhynchus mykiss). To further verify that we had identified leptin, the response of fish "leptin" was measured in fed and fasted green sunfish. Fed sunfish had approximately threefold higher concentration of leptin in blood than did fasted sunfish (fed vs. fasted; 0.599 +/- 0.03 microg/microl vs. 0.196 +/- 0.04 microg/microl; P > F = 0.0001), which is consistent with mammalian models of leptin function. Brain leptin concentration is also positively correlated with percent body fat in white crappie and bluegill. Based upon electrophoretic mobility, immunoreactivity, response to fasting, and correlation with adiposity, we believe we have the first evidence for leptin expression in an ectotherm.

Adipose Tissue↗
PubMed2000

Needle diameter in outpatient myelography: rates of adverse effects and current practice trends.

Telephone calls were made to 1251 consecutive patients one day following outpatient myelography. Data were available on 518 patients punctured with 22-gauge (g) (large-diameter) and 465 with 25-g (small-diameter) spinal needles. We surveyed 48 academic and private practice groups regarding needle diameter use in myelography; data were obtained from 34 private practice and 14 academic radiology departments. Patients reported adverse effects including mild and severe headache, back pain and nausea. The percentage of total adverse effects was significantly greater in the 22-g than in the 25-g needle group. The percentage of patients with headache was higher in the 22-g than in the 25-g group, but this difference was not statistically significant. Only 19% of private practice groups and 17% of academic centers use 25-g needles; the remainder use 20-g or 22-g needles.

Adult↗
PubMed2000

Diagnosing and managing seasonal affective disorder.

Mood and behavior changes that have a seasonal pattern were first called seasonal affective disorder (SAD) in 1984. SAD, which affects about 5% of Americans, is most common among reproductive-age women. Afflicted patients typically experience debilitating somatic complaints of fatigue, discomfort, lethargy and atypical depressive complaints of hypersomnia, increased appetite, carbohydrate craving, and weight gain. This article presents current issues in the clinical assessment and management of SAD.

Antidepressive Agents↗