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Biomedical subjects

G S Smith

Publications and source records attributed to G S Smith.

At least 19 recordsLinked to original sources
PubMed2006

Blurring the distinctions between on and off the job injuries: similarities and differences in circumstances.

OBJECTIVES: To compare the causes of non-fatal work and non-work injuries and the places or environments where they occur. It has been suggested that many injuries may have similar etiologies on and off the job and thus involve some common prevention strategies. However lack of comparable data on work relatedness has prevented testing this proposition. METHODS: The National Health Interview Survey (NHIS) now collects information on the cause, location, and work relatedness of all medically attended injuries. National US estimates of non-fatal work and non-work injuries were compared by cause and place/location for working age adults (18-64 years). RESULTS: Overall 28.6% of injuries to working age adults were work related (37.5% among employed people). The causes and locations of many work and non-work injuries were similar. Falls, overexertion, and struck/caught by were leading causes for work and non-work injuries. Motor vehicle injuries were less likely to be work related (3.4% at work v 19.5% non-work) and overexertion injuries more likely to be work related (27.1% v 13.8%). Assaults were less than 1% of work injuries and 1.8% of non-work injuries. Both work and non-work injuries occurred in every location examined-including the home where 3.5% of injuries were work related. CONCLUSIONS: Work and non-work injuries share many similarities suggesting opportunities to broaden injury prevention programs commonly restricted to one setting or the other. Comprehensive efforts to prevent both non-work and work injuries may result in considerable cost savings not only to society but also directly to employers, who incur much of the associated costs.

Accidental Falls↗
PubMed2005

Effects of the dopaminergic agent and NMDA receptor antagonist amantadine on cognitive function, cerebral glucose metabolism and D2 receptor availability in chronic traumatic brain injury: a study using positron emission tomography (PET).

PRIMARY OBJECTIVE: This study was performed to assess effects of amantadine (AMH), a dopaminergic agent and NMDA antagonist, on chronic traumatic brain injury (TBI). The primary hypotheses were that amantadine treatment would result in executive function improvement and increased activity in pre-frontal cortex. RESEARCH DESIGN: An open-label design was used. METHODS: Twenty-two subjects underwent neuropsychological testing pre- and post-12 week treatment. Six subjects also underwent PET scanning. INTERVENTION: Amantadine 400 mg was administered per day. RESULTS: Significant improvements on tests of executive function were observed with treatment. Analysis of PET data demonstrated a significant increase in left pre-frontal cortex glucose metabolism. There was a significant positive correlation between executive domain scores and left pre-frontal glucose metabolism. CONCLUSIONS: This is the first known study to assess amantadine in chronic TBI using PET and the data are consistent with the hypotheses. The conduction of further studies is warranted.

Amantadine↗
PubMed2005

Welding related occupational eye injuries: a narrative analysis.

OBJECTIVE: To determine the activities and circumstances proximal to a welding related occupational eye injury, a hybrid narrative coding approach derived from two well developed classification systems was developed to categorize and describe the activity, initiating process, mechanism of injury, object and/or substance, and the use of protective eyewear from the narrative text data reported for each injury. METHODS: Routinely collected workers' compensation claims over a one year period (2000) were analyzed from a large US insurance provider. An index term search algorithm of occupation, incident, and injury description fields identified 2209 potential welding related eye injury claims. After detailed review of these claims, 1353 welders and 822 non-welders were analyzed. RESULTS: During 2000, eye(s) as the primary injured body part accounted for 5% (n = 26 413) of all compensation claims. Eye injuries accounted for 25% of all claims for welders. Subjects were mainly male (97.1%) and from manufacturing (70.4%), service (11.8%), or construction (8.4%) related industries. Most injuries were foreign body (71.7%) or burn (22.2%) and 17.6% were bilateral. Common activities include welding (31.9%) and/or grinding (22.5%). Being struck by an airborne object occurred in 56.3% of cases. Non-welders showed similar patterns except that burns (43.8%) were more frequent and more often initiated by another worker (13.9%). CONCLUSIONS: Narrative injury text provides valuable data to supplement traditional epidemiologic analyses. Workers performing welding tasks or working nearby welders should be trained to recognize potential hazards and the effective use of proper safety equipment to prevent ocular injury.

Accidents, Occupational↗
PubMed2004

Symptomatic and radiological follow-up after para-esophageal hernia repair.

The treatment of para-esophageal hernia by the laparoscopic approach has been described by a number of authors. The lower morbidity of the laparoscopic approach compared with the open approach holds some attraction, however, reservations regarding the durability of laparoscopic repair exist. There is a paucity of objective follow-up data in the literature with regard to repair durability and symptomatic outcome. A review was undertaken of 94 patients over a 7 year period undergoing attempted laparoscopic repairs of para-esophageal hernia. Preoperative and operative data was collected and patients underwent postoperative interview and barium meal. Laparoscopic repair was successfully completed in 86 patients. Symptomatic reherniation occurred in 12% (10/86) of patients undergoing laparoscopic repair. These patients underwent open reoperative surgery. There were no symptomatic recurrences in patients undergoing initial open repair. Symptomatic outcome was assessed by interview in 78% (73/94) of patients at a median of 27 months (3-93 months) postoperatively. Ninety-seven percent (71/73) of patients were satisfied with their ultimate symptomatic outcome however, this group included seven patients who had required reoperative surgery for symptomatic recurrence and were therefore laparoscopic failures. In order to determine the asymptomatic recurrence rate patients were requested to undergo a barium meal. A further nine small asymptomatic recurrences were diagnosed in 42 patients having had laparoscopic repair. This represents an asymptomatic radiographic recurrence rate of 21%. Laparoscopic repair in this series was associated with a 12% symptomatic recurrence rate. The majority of patients with symptomatic recurrence underwent open reoperation with good results. Strategies for reducing recurrences should be examined in prospective series.

Adolescent↗
PubMed2004

Using narrative text and coded data to develop hazard scenarios for occupational injury interventions.

OBJECTIVE: To determine whether narrative text in safety reports contains sufficient information regarding contributing factors and precipitating mechanisms to prioritize occupational back injury prevention strategies.Design, setting, subjects, and MAIN OUTCOME MEASURES: Nine essential data elements were identified in narratives and coded sections of safety reports for each of 94 cases of back injuries to United States Army truck drivers reported to the United States Army Safety Center between 1987 and 1997. The essential elements of each case were used to reconstruct standardized event sequences. A taxonomy of the event sequences was then developed to identify common hazard scenarios and opportunities for primary interventions. RESULTS: Coded data typically only identified five data elements (broad activity, task, event/exposure, nature of injury, and outcomes) while narratives provided additional elements (contributing factor, precipitating mechanism, primary source) essential for developing our taxonomy. Three hazard scenarios were associated with back injuries among Army truck drivers accounting for 83% of cases: struck by/against events during motor vehicle crashes; falls resulting from slips/trips or loss of balance; and overexertion from lifting activities. CONCLUSIONS: Coded data from safety investigations lacked sufficient information to thoroughly characterize the injury event. However, the combination of existing narrative text (similar to that collected by many injury surveillance systems) and coded data enabled us to develop a more complete taxonomy of injury event characteristics and identify common hazard scenarios. This study demonstrates that narrative text can provide the additional information on contributing factors and precipitating mechanisms needed to target prevention strategies.

Accidental Falls↗
PubMed2002

Laparoscopic excision of a Brunner's gland hamartoma of the duodenum.

Brunner's gland hamartoma (adenoma) was first described in 1876. It is a rare hamartomatous lesion, with only 100 cases reported in the world literature. Treatment has been by endoscopic snaring. Open surgical excision was reserved for cases where snaring had failed. We report a case of a Brunner's gland hamartoma (2.4 cm) that was successfully resected by laparoscopic techniques. Postoperative hospital stay was brief (2 days), and there were no complications. This is the second reported case to be resected laparoscopically.

Brunner Glands↗
PubMed2002

Effects of maternal betamethasone administration on fetal and maternal blood pressure and heart rate in the baboon at 0.7 of gestation.

OBJECTIVE: We sought to determine the effects of the intramuscular maternal administration of betamethasone to the pregnant baboon at 0.7 of gestation on fetal blood pressure and heart rate. STUDY DESIGN: We treated pregnant baboons at 0.7 of gestation with intramuscular betamethasone (n = 4), at a weight-adjusted dose equivalent to the daily dose administered to women in preterm labor or with saline solution (n = 5). Four injections were given at 12-hour intervals. Fetal and maternal blood pressure and heart rate were recorded continuously. Within-group differences and between-group differences were analyzed with repeated measures analysis of variance. RESULTS: Fetal blood pressure increased significantly after betamethasone treatment. Fetal heart rate, maternal blood pressure, and heart rate did not change. CONCLUSION: Exposure of the developing primate fetus to exogenous glucocorticoid at 0.7 of gestation elevates fetal blood pressure. These findings confirm and extend the observations in the fetal sheep. Further studies are needed to evaluate the mechanisms that are involved and possible long-term consequences of these cardiovascular effects of antenatal glucocorticoid exposure in the fetal primate.

Animals↗
PubMed2001

Drinking and recreational boating fatalities: a population-based case-control study.

CONTEXT: Alcohol is increasingly recognized as a factor in many boating fatalities, but the association between alcohol consumption and mortality among boaters has not been well quantified. OBJECTIVES: To determine the association of alcohol use with passengers' and operators' estimated relative risk (RR) of dying while boating. DESIGN, SETTING, AND PARTICIPANTS: Case-control study of recreational boating deaths among persons aged 18 years or older from 1990-1998 in Maryland and North Carolina (n = 221), compared with control interviews obtained from a multistage probability sample of boaters in each state from 1997-1999 (n = 3943). MAIN OUTCOME MEASURE: Estimated RR of fatality associated with different levels of blood alcohol concentration (BAC) among boaters. RESULTS: Compared with the referent of a BAC of 0, the estimated RR of death increased even with a BAC of 10 mg/dL (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.2-1.4). The OR was 52.4 (95% CI, 25.9-106.1) at a BAC of 250 mg/dL. The estimated RR associated with alcohol use was similar for passengers and operators and did not vary by boat type or whether the boat was moving or stationary. CONCLUSIONS: Drinking increases the RR of dying while boating, which becomes apparent at low levels of BAC and increases as BAC increases. Prevention efforts targeted only at those operating a boat are ignoring many boaters at high risk. Countermeasures that reduce drinking by all boat occupants are therefore more likely to effectively reduce boating fatalities.

Accidents↗
PubMed2001

Role of calcium homeostasis in gastric mucosal injury and protection.

Using a human gastric mucosal cell line, known as AGS cells, we determined the role that perturbations in intracellular Ca2+ concentration [Ca2+]i might play in cellular injury induced by various damaging agents. For deoxycholate (CD) and ethanol (EtOH) induced damage, a concentration related increase in [Ca2+]i was noted that preceded and closely paralleled the magnitude of injury. Thus, the higher the concentration of DC or EtOH, the more profound were the changes in [Ca2+]i and the resultant degree of cellular injury. Pretreatment with a low concentration of DC (50 microM; called a mild irritant) that was not damaging by itself attenuated injury induced by a damaging concentration (i.e. 250 microM) of DC, and appeared to elicit this protective action through mechanisms that resisted intracellular Ca2+ accumulation. Additional studies indicated that the mechanism of aspirin damage may be similar and that other protective agents such as prostaglandins and growth factors appear to mediate their protective properties through prevention of intracellular Ca2+ alterations. We propose that agents that prevent mucosal injury mediate this activity through a cellular response (involving active Ca2+ efflux) that subsequently provides a protective action by limiting the magnitude of intracellular Ca2+ accumulation.

Aspirin↗
PubMed2001

Analyses of [(18)F]altanserin bolus injection PET data. II: consideration of radiolabeled metabolites in humans.

Imaging serotonin-2A (5-HT(2A)) neuroreceptors with positron emission tomography (PET) and [(18)F]altanserin has been the focus of a series of PET studies, as [(18)F]altanserin is one of the most selective 5-HT(2A) antagonist radiotracers. Previous animal studies showed that radiolabeled metabolites (radiometabolites) of [(18)F]altanserin crossed the blood-brain barrier (BBB) to localize nonspecifically in brain, consistent with a constant radioactivity "background." In this work, we evaluated human bolus injection [(18)F]altanserin PET data with detailed consideration of the impact of BBB-permeable metabolites on the specific binding parameters. Data were quantified using either single (parent radiotracer), dual (parent radiotracer and radiometabolites), or no arterial input function(s) (cerebellum as reference tissue input function). A step-gradient high-performance liquid chromatography (HPLC) analysis provided distinct separation of [(18)F]altanserin and four radiolabeled components in plasma. After [(18)F]altanserin injection, the step-gradient data showed that the major BBB-permeable radiometabolites approached constant levels in plasma (>50 min), consistent with a constant metabolite "background." The single-input Logan graphical results were highly correlated with the dual-input results and its bias was fairly constant across regions and subjects, as similarly observed for a nongraphical reference tissue method. The most comprehensive and quantitatively valid analysis for bolus [(18)F]altanserin PET data was the dual-input method that specifically accounted for BBB-permeable metabolites, although the Logan analysis was preferred because it provided a good compromise between validity, sensitivity, and reliability of implementation. Further study is needed to better understand how the cerebellar kinetics of [(18)F]altanserin and its radiometabolites impact the reference tissue measures.

Adolescent↗
PubMed2001

Decreased type IV collagenase activity in experimental pancreatic fibrosis.

BACKGROUND: Severe hyperstimulation and duct obstruction pancreatitis (SHOP) is characterized by pancreatic fibrosis and loss of acinar cell mass. MMP-2 and MMP-9 are type IV collagenases and gelatinases. We hypothesized that fibrosis results from disruption of the normal collagen homeostasis and that altered activity of the type IV collagenases may contribute to pancreatic fibrosis in SHOP. METHODS: SHOP rats (n = 15) were prepared with pancreatic duct obstruction and cerulein (50 microg/kg/d, ip) hyperstimulation. Pancreas from unoperated control (n = 8), 48 h SHOP (n = 8), and 96 h SHOP (n = 7) rats was harvested, homogenized, and assayed for protein concentration (BCA method). Type IV collagenase (MMP-2 and MMP-9) expression was measured by zymography using gelatin as substrate. Type IV collagenase activity was quantified with a fluorescence assay. RESULTS: Expression of the active form of MMP-9 decreased while latent MMP-9 and active and latent MMP-2 increased on gelatin zymography. Activity of type IV collagenases (MMP-2 and MMP-9) progressively decreases with SHOP injury. The differences between expression and activity are likely due to posttranslational regulators such as MT-MMPs and TIMPs. CONCLUSIONS: Collagenase expression and activity are decreased in the SHOP model of pancreatitis, suggesting a decrease in the homeostatic mechanisms for type IV collagen in the extracellular matrix. Therefore, early fibrosis in the SHOP model is, at least in part, due to alterations in collagen homeostasis and not simply increased collagen production.

Animals↗
PubMed2001

Alcohol/drug abuse, driving convictions, and risk-taking dispositions among trauma center patients.

The objective of this study was to evaluate the relationship between alcohol/drug abuse diagnoses, driving convictions (speeding, reckless driving, impaired driving, license violations), and risk-taking dispositions among a series of injured drivers admitted to a trauma center. The driving records of 778 patients were linked to diagnoses of psychoactive substance use disorders (PSUDs), admission blood alcohol concentration (BAC), mode of injury, and results of a risk-taking disposition survey. Twenty-nine percent of patients had one or more convictions in the 3 years before injury. Types of violation were not related to mode of injury. Although there was a positive association between prior impaired-driving convictions, current alcohol dependence, and a BAC + status, a consistent pattern relative to other violations, PSUDs, and BAC status was not apparent. Risk-taking disposition scale scores indicated that patients without PSUDs and without convictions tended toward less risk-taking behavior than patients with PSUDs and with convictions. The complex inter-relationships between PSUDs, risk-taking dispositions, and being convicted of driving dangerously require additional study so that intervention programs and injury prevention initiatives can be targeted effectively.

Accidents, Traffic↗
PubMed2001

Synchrotron X-ray study of lung surfactant-specific protein SP-B in lipid monolayers.

This work reports the first x-ray scattering measurements to determine the effects of SP-B(1-25), the N-terminus peptide of lung surfactant-specific protein SP-B, on the structure of palmitic acid (PA) monolayers. In-plane diffraction shows that the peptide fluidizes a portion of the monolayer but does not affect the packing of the residual ordered phase. This implies that the peptide resides in the disordered phase, and that the ordered phase is essentially pure lipid, in agreement with fluorescence microscopy studies. X-ray reflectivity shows that the peptide is oriented in the lipid monolayer at an angle of approximately 56 degrees relative to the interface normal, with one end protruding past the hydrophilic region into the fluid subphase and the other end embedded in the hydrophobic region of the monolayer. The quantitative insights afforded by this study lead to a better understanding of the lipid/protein interactions found in lung surfactant systems.

Amino Acid Sequence↗
PubMed2001

Packing of ganglioside-phospholipid monolayers: an x-ray diffraction and reflectivity study.

Using synchrotron grazing-incidence x-ray diffraction (GIXD) and reflectivity, the in-plane and out-of-plane structure of mixed ganglioside-phospholipid monolayers was investigated at the air-water interface. Mixed monolayers of 0, 5, 10, 20, and 100 mol% ganglioside GM(1) and the phospholipid dipalmitoylphosphatidylethanolamine (DPPE) were studied in the solid phase at 23 degrees C and a surface pressure of 45 mN/m. At these concentrations and conditions the two components do not phase-separate and no evidence for domain formation was observed. X-ray scattering measurements reveal that GM(1) is accommodated within the host DPPE monolayer and does not distort the hexagonal in-plane unit cell or out-of-plane two-dimensional (2-D) packing compared with a pure DPPE monolayer. The oligosaccharide headgroups were found to extend normally from the monolayer surface, and the incorporation of these glycolipids into DPPE monolayers did not affect hydrocarbon tail packing (fluidization or condensation of the hydrocarbon region). This is in contrast to previous investigations of lipopolymer-lipid mixtures, where the packing structure of phospholipid monolayers was greatly altered by the inclusion of lipids bearing hydrophilic polymer groups. Indeed, the lack of packing disruptions by the oligosaccharide groups indicates that protein-GM(1) interactions, including binding, insertion, chain fluidization, and domain formation (lipid rafts), can be studied in 2-D monolayers using scattering techniques.

Air↗
PubMed2001

Comparison and analysis of laparoscopic intracorporeal suturing devices: preliminary results.

BACKGROUND AND PURPOSE: One of the most challenging aspects of laparoscopic surgery is intracorporeal suturing and knot tying. A loss of depth perception and tactile sense and visual obstruction make placing accurate and well-tied knots a difficult and time-consuming task. Two devices conceived to ease the task of suturing and knotting while presumably speeding performance are the Suture Assist (SA; Ethicon Endo-Surgery) and EndoStitch (ES; US Surgical/Tyco). We set out to objectively assess suture placement accuracy and knot speed and strength of these two suturing devices and conventional laparoscopic suturing (CS). MATERIALS AND METHODS: To date, six surgeons with laparoscopic experience were trained on the three suturing techniques. A pelvic trainer was set up with a freshly marked and incised swine renal pelvis and ureter. Each surgeon placed four sutures of 2-0 polyester suture with each technique (repeated on three separate occasions) with five half-hitches for a total of 216 knots. Time, strength, and accuracy were measured for each suture/knot placement. The knot distance was then measured from the marked target using calipers and carefully dissected from the tissue. Each knot was individually tested on a Monsanto Model 10 tensiometer, whereby slippage, strength, and breakage points were determined. RESULTS: The mean times (min:sec) and accuracy (millimeters) were as following: CS 5:08 and 0.457, ES 2:45 and 0.660, and SA 2:40 and 0.508. The difference in time was found to be statistically significant (P < 0.001), while the difference in accuracy was not. Only 182 of 216 knots were able to be included for analysis because of either a small knot lumen or device failure. Device failures necessitating intervention were encountered only with the SA, which had a misfire rate of 9.7% (7 of 72). The mean knot strength was measured at 41.1 N for CS, 57.3 N for SA, and 28.0 for ES. Knot break percentage (breakage) was calculated as 50.8% for CS, 20.7% for ES, and 95% for SA. CONCLUSION: Preliminary results show that each of the laparoscopic suturing devices has distinct advantages over conventional intracorporeal suturing and tying. Decreased times and comparable, if not greater, knot strengths may translate into improved laparoscopic suturing/tying performance for laparoscopic intracorporeal suturing devices.

Equipment Design↗
PubMed2001

Total anomalous pulmonary venous connection and a constellation of craniofacial, skeletal, and urogenital anomalies in a newborn and similar features in his 36-year-old father.

We report on a newborn male born to non-consanguineous parents with total anomalous pulmonary venous connection (TAPVC) and additional findings of malformed ears, hypertelorism, brachyphalangy in the hands, pterygium of the elbows, knees, and wrists, complex lower limb pre-axial polydactyly, tibial shortening, clubfeet, horseshoe kidney and a micropenis. He had a 46,XY karyotype. His 36-year-old father had similar craniofacial and limb anomalies suggesting an autosomal dominant syndrome with variable expression. Our patients may represent the 3rd and 4th examples of a newly-described syndrome by Baraitser et al. [(1997) Clin Dysmorphol 6:111-121] which is distinguished by malformed ears, complex pre-axial polydactyly and tibial aplasia in the lower limbs, severe brachyphalangy in the hands, and a micropenis.

Abnormalities, Multiple↗