Post-traumatic epidermoid cyst presenting with headache.
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Biopsy↗
Biomedical subjects
D R Roberts
Publications and source records attributed to D R Roberts.
Comparative study of analgesic efficacy and morphine-sparing effect of intramuscular dexketoprofen trometamol with ketoprofen or placebo after major orthopaedic surgery.
AIMS: Multimodal analgesia is thought to produce balanced and effective postoperative pain control. A combined therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) and opiates could result in synergistic analgesia by acting through different mechanisms. Currently there are very few parenterally administered NSAIDs suitable for the immediate postoperative period. Therefore, this study was undertaken to assess the analgesic efficacy, relative potency, and safety of parenteral dexketoprofen trometamol following major orthopaedic surgery. METHODS: One hundred and seventy-two patients elected for prosthetic surgery, were randomized to receive two intramuscular injections (12 hourly) of either dexketoprofen 50 mg, ketoprofen 100 mg or placebo in a double-blind fashion. Postoperatively, the patient's pain was stabilized, then they were connected to a patient- controlled analgesia system (PCA) of morphine for 24 h (1 mg with 5 min lockout). RESULTS: The mean cumulative amount of morphine (CAM) used was of 39 mg in the dexketoprofen group and 45 mg in the ketoprofen group vs 64 mg in the placebo group. (Reduction in morphine use was approximately one-third between the active compounds compared with placebo (adjusted mean difference of -25 mg between dexketoprofen and placebo and -23 mg between ketoprofen and placebo. These differences were statistically significant: P </= 0.0003; 95% CI -35, -14. Pain-intensity scores were consistently lower with the active compounds, the lowest corresponded to the dexketoprofen-treated patients. Regarding sedation, there were statistically significant differences between the two active compounds and placebo only at the 2nd and 13th hours. Wound bleeding was specifically measured with no statistically significant differences found between all the groups. CONCLUSIONS: Intramuscular administration of dexketoprofen trometamol 50 mg has good analgesic efficacy both in terms of opioid-sparing effect and control of pain after major orthopaedic surgery.
Adolescent↗
Unilateral left prefrontal transcranial magnetic stimulation (TMS) produces intensity-dependent bilateral effects as measured by interleaved BOLD fMRI.
Transcranial magnetic stimulation (TMS) administered over the prefrontal cortex has been shown to subtly influence neuropsychological tasks, and has antidepressant effects when applied daily for several weeks. Prefrontal TMS does not, however, produce an immediate easily observable effect, making it hard to determine if one has stimulated the cortex. Most prefrontal TMS studies have stimulated using intensity relative to the more easily determined motor threshold (MT) over motor cortex. Five healthy adults were studied in a 1.5 T MRI scanner during short trains of 1 Hz TMS delivered with a figure eight MR compatible TMS coil followed by rest epochs. In a randomized manner, left prefrontal TMS was delivered at 80%, 100% and 120% of MT interleaved with BOLD fMRI acquisition. Compared to rest, all TMS epochs activated auditory cortex, with 80% MT having no other areas of significant activation. 100% MT showed contralateral activation and 120% MT showed bilateral prefrontal activation. Higher intensity TMS, compared to lower, in general produced more activity both under the coil and contralaterally. Higher prefrontal TMS stimulation intensity produces greater local and contralateral activation. Importantly, unilateral prefrontal TMS produces bilateral effects, and TMS at 80% MT produces only minimal prefrontal cortex activation.
Adult↗
DDT house spraying and re-emerging malaria.
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Animals↗
Mortality among rubber chemical manufacturing workers.
BACKGROUND: A retrospective cohort mortality study evaluated ischemic heart disease (IHD) among workers in the "rubber chemicals" manufacturing department of a Western New York plant. A previous study at the plant found elevated chest pain and angina among workers in this department. METHODS: Mortality experience of workers employed from 1946-1988 was followed through December 31, 1994. Mortality was compared to U.S. population rates and to local Niagara county rates by using the NIOSH life table analysis system. Poisson regression was used to examine patterns of IHD within the cohort. RESULTS: The standardized mortality ratio (SMR) for IHD among workers in the rubber chemicals department was 1.51 (U.S. rates) and 1.19 (Niagara county rates). Increased mortality from IHD in the rubber chemicals department was most pronounced at younger ages (< 50, SMR = 2.4); workers in a second chemical production department also had an elevated (but not statistically significant) SMR of 1.5 for IHD. CONCLUSIONS: IHD mortality among workers in the rubber chemicals department was elevated, particularly among those under 50 years of age. Potential occupational risk factors for IHD include the rotating shift pattern for employees assigned to two chemical production departments and chemical exposures present in the rubber chemicals department.
Adolescent↗
Balancing risks on the backs of the poor.
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Animals↗
Pulmonary edema in patients after liver transplantation.
The aim of this study is to determine the incidence of radiological pulmonary edema in elective liver transplant recipients and its relationship to perioperative factors and postoperative course. We reviewed 102 chest radiographs from 34 patients who had undergone orthotopic liver transplantation (OLT). Films were assessed by 2 trained radiologists for evidence of pulmonary edema using a standardized system. Clinical and outcome data from the 34 patients were also recorded. There was a high incidence (47%) of postoperative radiological pulmonary edema that was associated with deterioration in gaseous exchange, elevated pulmonary artery pressure, and increased duration of ventilator dependence and intensive care stay. Eighteen percent of the patients developed edema immediately after surgery, which was associated with greater pulmonary artery pressure and transfusion requirements during surgery. An additional 29% developed edema during the next 16 to 20 hours, but there was no association with fluid replacement. We conclude that pulmonary edema is common after OLT and will influence postoperative recovery in a substantial proportion of transplant recipients. Excess perioperative fluid replacement is unlikely to be the sole mechanism of edema in these patients.
Female↗
Motor cortex brain activity induced by 1-Hz transcranial magnetic stimulation is similar in location and level to that for volitional movement.
RATIONALE AND OBJECTIVES: The relatively high temporal and spatial resolution of functional MR imaging was used to compare the blood oxygenation level dependent (BOLD) response associated with movement induced by transcranial magnetic stimulation (TMS) with that for a similar movement executed volitionally (VOL). METHODS: Seven healthy adults were studied in a 1.5-T MR scanner. One hertz TMS at 110% of motor threshold was applied over the motor cortex for the thumb in 21-pulse trains in alternation with VOL every 63 seconds and interleaved with functional MR imaging. RESULTS: BOLD increases in motor cortex associated with TMS and VOL movement were similar (2%-3%). Mean separation of their centers of activity was 3.7 + 1.9 mm (mean displacement: left/right = 0.3 +/- 4.1 mm; superior/inferior = 0.7 +/- 1.9 mm). There was no indication of supraphysiological brain activity. CONCLUSIONS: Motor cortex BOLD response associated with thumb movement induced by 1-Hz TMS at 110% motor threshold is similar in both location and level to that caused by a similar movement executed volitionally.
Adult↗
A probability model of vector behavior: effects of DDT repellency, irritancy, and toxicity in malaria control.
A probability model of how DDT residues may function within a malaria control program is described. A step-wise organization of endophagic behaviors culminates in a vector acquiring a human blood meal inside the house. Different vector behaviors are described, epidemiologically defined, temporally sequenced, and quantified with field data. Components of vector behavior and the repellent, irritant, and toxic actions of insecticide residues are then assembled into a probability model. The sequence of host-seeking behaviors is used to partition the total impact of sprayed walls according to the three chemical actions. Quantitatively, the combined effect of repellency and irritancy exert the dominant actions of DDT residues in reducing man-vector contact inside of houses. These relationships are demonstrated with published and unpublished data for two separate populations of Anopheles darlingi, for Anopheles gambiae and Anopheles funestus in Tanzania, and Anopheles punctulatus in New Guinea.
Animals↗
A comparison study of house entering and exiting behavior of Anopheles vestitipennis (Diptera: Culicidae) using experimental huts sprayed with DDT or deltamethrin in the southern district of Toledo, Belize, C.A.
An investigation of the house entering and exiting behavior of Anopheles vestitipennis Dyar and Knab was undertaken in the Toledo District of Belize, Central America, between March and December of 1998. Three untreated experimental huts were either fitted with exit or entrance interception traps or used as a control for human landing collections. Human landing collections showed that An. vestitipennis exhibited a high level of biting activity shortly after sunset and continued biting at high levels throughout the night. Under unsprayed conditions, the use of exit and entrance interception traps demonstrated that doors, windows, and eaves were the primary mode of entry; whereas, cracks in the walls served a secondary role. The peak entrance time for An. vestitipennis occurred between 6:45 P.M. and 9:45 P.M. and a peak exit time occurred between 11:45 P.M. and 4:45 A.M. Additional trials were conducted after spraying one of the huts with DDT and another with deltamethrin. The excito-repellent properties of deltamethrin did not affect entrance times but did result in a peak exiting behavior that was five hours earlier than under pre-spray conditions. Deltamethrin also exhibited a repellency effect, showing 66% fewer An. vestitipennis entering the hut two weeks post-spray. DDT had an even more powerful repellency effect resulting in a 97% post-spray reduction of An. vestitipennis females entering the hut up to two weeks post-spray. The control hut showed only a 37% reduction in An. vestitipennis as compared to pre-spray conditions.
Animals↗
Malaria in the Americas: a model of reemergence.
Malaria in the Americas is a reemerging health issue. In 1969, the World Health Organization shifted policy from malaria eradication to malaria control. With this shift, vector control (house spraying with dichlorodiphenyltrichloroethane [DDT]) was deemphasized. Since that time, house spray rates have decreased and malaria rates have increased. Using malaria data collected since 1959 by the Pan American Health Organization, this relationship was examined with an ecological regression model. Malaria control was found to be a function of policy, disease burden, and vector control (R2 = 0.75, p < 0.001). Policy must address both disease burden and vector control. Treatment of disease burden is unquestioned; however, vector control is debated. An argument for the judicious and enlightened resumption of house spraying with DDT is presented.
Central America↗
Plasmodium vivax polymorphs and Plasmodium falciparum circumsporozoite proteins in Anopheles (Diptera: Culicidae) from Belize, Central America.
Eight species of Anopheles mosquitoes from indoor/outdoor human landing collections in Belize, Central America, were examined for human Plasmodium circumsporozoite protein (CSP) using an enzyme-linked immunosorbent assay (ELISA). A total of 14 of 9,104 females tested were positive from general surveys throughout Belize and three of 11,966 were positive from a longitudinal study in Caledonia, northern Belize. ELISA results, using pooled head-thorax preparations and species-specific monoclonal antibodies directed against the circumsporozoite proteins of Plasmodium falciparum and two Plasmodium vivax polymorphs (210 and VK247), found four species reactive: Anopheles vestitipennis (3 pools), Anopheles darlingi (2 pools), Anopheles albimanus (10 pools), and Anopheles gabaldoni (2 pools). The minimum field infection rates (MFIR) for combined Plasmodium species from the general survey were 0.282% for An. vestitipennis, 0.271% for An. darlingi, 0.126% for An. albimanus, and 0.395% for An. gabaldoni. MFIRs for combined Plasmodium species from the longitudinal study in the village of Caledonia were 0.018% for both An. vestitipennis and An. albimanus and 1.66% for An. gabaldoni. Positive CSP pools were collected from the Cayo, Corozal, Orange Walk, Stann Creek, and Toledo political districts. No CSP positive pools were detected from collections in the Belize District. The study provides valuable information on the spatial distribution and species type of Plasmodium positive mosquitoes. This information, in combination with other vector data, suggest that An. vestitipennis and An. darlingi are commonly involved in malaria transmission. Additionally, these species appear to be much more efficient vectors than An. albimanus in Belize.
Animals↗
A combined TMS/fMRI study of intensity-dependent TMS over motor cortex.
BACKGROUND: Transcranial magnetic stimulation (TMS) allows noninvasive stimulation of neurons using time-varying magnetic fields. Researchers have begun combining TMS with functional imaging to simultaneously stimulate and image brain activity. Recently, the feasibility of interleaving TMS with functional magnetic resonance imaging (fMRI) was demonstrated. This study tests this new method to determine if TMS at different intensities shows different local and remote activation. METHODS: Within a 1.5 Tesla (T) MRI scanner, seven adults were stimulated with a figure-eight TMS coil over the left motor cortex for thumb, while continuously acquiring blood oxygen level dependent (BOLD) echoplanar images. TMS was applied at 1 Hz in 18-second long trains delivered alternately at 110% and 80% of motor threshold separated by rest periods. RESULTS: Though the TMS coil caused some artifacts and reduced the signal to noise ratio (SNR), higher intensity TMS caused greater activation than lower, both locally and remotely. The magnitude (approximately 3% increase) and temporal onset (2 to 5 sec) of TMS induced blood flow changes appear similar to those induced using other motor and cognitive tasks. CONCLUSIONS: Though work remains in refining this potentially powerful method, combined TMS/fMRI is both technically feasible and produces measurable dose-dependent changes in brain activity.
Adult↗
Induced hypothermia in the management of cerebral oedema secondary to fulminant liver failure.
The use of mild hypothermia in the management of blunt head trauma has been shown to significantly improve clinical outcomes. The use of moderate controlled hypothermia in the patient with severely raised intracranial pressure (ICP) secondary to fulminant hepatic failure (FHF) has similar potential benefits, but is not a widely accepted practice. We report a case where the use of hypothermia in the management of severely raised ICP both before and after liver transplantation was thought to effect a beneficial outcome.
Adult↗
Population structure of the primary malaria vector in South America, Anopheles darlingi, using isozyme, random amplified polymorphic DNA, internal transcribed spacer 2, and morphologic markers.
A genetic and morphologic survey of Anopheles darlingi populations collected from seven countries in Central and South America was performed to clarify the taxonomic status of this major malaria vector species in the Americas. Population genetics was based on three techniques including isozyme, random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR), and internal transcribed spacer 2 (ITS2) markers. The results of the isozyme analysis indicated moderate differences in the allele frequencies of three putative loci (glutamate oxalaoacetate transaminase-1, isocitrate dehydrogenase-1, and phosphoglucomutase) of the 31 analyzed. No fixed electromorphic differences separated the populations of An. darlingi, which showed little genetic divergence (Nei distances = 0.976-0.995). Fragments produced by RAPD-PCR demonstrated evidence of geographic partitioning and showed that all populations were separated by small genetic distances as measured with the 1 - S distance matrix. The ITS2 sequences for all samples were identical except for four individuals from Belize that differed by a three-base deletion (CCC). The morphologic study demonstrated that the Euclidean distances ranged from 0.02 to 0.14, with the highest value observed between populations from Belize and Bolivia. Based on these analyses, all the An. darlingi populations examined demonstrated a genetic similarity that is consistent with the existence of a single species and suggest that gene flow is occurring throughout the species' geographic range.
Animals↗
Characterization and detection of Anopheles vestitipennis and Anopheles punctimacula (Diptera: Culicidae) larval habitats in Belize with field survey and SPOT satellite imagery.
Surveys of larval habitats of Anopheles vestitipennis and Anopheles punctimacula were conducted in Belize, Central America. Habitat analysis and classification resulted in delineation of eight habitat types defined by dominant life forms and hydrology. Percent cover of tall dense macrophytes, shrubs, open water, and pH were significantly different between sites with and without An. vestitipennis. For An. punctimacula, percent cover of tall dense macrophytes, trees, detritus, open water, and water depth were significantly different between larvae positive and negative sites. The discriminant function for An. vestitipennis correctly predicted the presence of larvae in 65% of sites and correctly predicted the absence of larvae in 88% of sites. The discriminant function for An. punctimacula correctly predicted 81% of sites for the presence of larvae and 45% for the absence of larvae. Canonical discriminant analysis of the three groups of habitats (An. vestitipennis positive; An. punctimacula positive; all negative) confirmed that while larval habitats of An. punctimacula are clustered in the tree dominated area, larval habitats of An. vestitipennis were found in both tree dominated and tall dense macrophyte dominated environments. The forest larval habitats of An. vestitipennis and An. punctimacula seem to be randomly distributed among different forest types. Both species tend to occur in denser forests with more detritus, shallower water, and slightly higher pH. Classification of dry season (February) SPOT multispectral satellite imagery produced 10 land cover types with the swamp forest and tall dense marsh classes being of particular interest. The accuracy assessment showed that commission errors for the tall, dense marsh and swamp forest appeared to be minor; but omission errors were significant, especially for the swamp forest (perhaps because no swamp forests are flooded in February). This means that where the classification indicates there are An. vestitipennis breeding sites, they probably do exist; but breeding sites in many locations are not identified and could be more abundant than indicated.
Animals↗
Multi-modality mapping of motor cortex: comparing echoplanar BOLD fMRI and transcranial magnetic stimulation. Short communication.
Multiple non-invasive methods of imaging brain function are now available for presurgical planning and neurobiological research. As these new methods become available, it is important to understand their relative advantages and liabilities, as well as how the information gained compares across different methods. A current and future trend in neurobiological studies as well as presurgical planning is to combine information from different imaging techniques. Multi-modal integration may perhaps give more powerful information than each modality alone, especially when one of the methods is transcranial magnetic stimulation (TMS), with its ability to non-invasively activate the brain. As an initial venture in cross comparing new imaging methods, we performed the following 2 studies, locating motor cortex with echoplanar BOLD fMRI and TMS. The two methods can be readily integrated, with concurring results, although each have important limitations.
Adult↗