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Biomedical subjects

D S Smith

Publications and source records attributed to D S Smith.

At least 181 records · Page 10Linked to original sources
PubMed1989

Prehospital countershock treatment of pediatric asystole.

Prehospital care was retrospectively reviewed in 117 pulseless nonbreathing (PNB) pediatric patients (0 to 18 years of age) to determine the effects of immediate countershock treatment of asystole. Of 90 (77%) children with an initial rhythm of asystole, 49 (54%) received countershock treatment. Rhythm change occurred in ten (20%) of the asystolic children who received countershock treatment. Three of the countershocked asystolic children were successfully resuscitated, but none survived. Rhythm change occurred in nine (22%) of the asystolic children not countershocked. Six were successfully resuscitated, and one survived. The two groups (countershocked asystole v noncountershocked asystole) did not differ significantly in age, sex, witnessed arrest, witnessed arrest with bystander basic life support (BLS), prehospital endotracheal intubation, both intubation and vascular access success, or diagnosis. However, prehospital vascular access was successfully established in a significantly greater number of countershocked patients (P less than .05). The mean times to the scene, at the scene, and to the hospital for the countershocked v noncountershocked asystolic patients were 6.2, 23.8, and 6.1 v 5.9, 14.7 and 7.0 minutes. The mean time at the scene was significantly greater in the countershock group (P less than .001). The successful performance of prehospital endotracheal intubation was significantly associated with rhythm change (P less than .05). Patients age, witnessed arrest, witnessed arrest with bystander BLS, successful establishment of prehospital vascular access, diagnosis, and countershock treatment were not significantly associated with rhythm change. In conclusion, prehospital countershock treatment prolonged prehospital care time and was not associated with rhythm change in asystolic children. Therefore, prehospital countershock treatment of asystolic children is not recommended.

Adolescent↗
PubMed1989

Acetylcholine sensitivity of the spine-test articular capsule of the sea urchin Eucidaris tribuloides.

1. The changes in the consistence of the spine-test articular capsule, or ligament, of the primary spines of Eucidaris tribuloides induced by acetylcholine (ACh) have been studied. Two complementary techniques were used: (a) "forced-vibration", which detects variations in the stiffness of the ligament along a single diametral plane; and (b) "forced-rotation" which records the spatial distribution of those changes. 2. ACh (1 microM to 1 mM) caused a rapid increase in the resistive force opposed by the ligament to passive stretching. Similar effects were elicited by several monoquaternary, N-substituted derivatives of trimethylammonium. 3. The opposite effect, i.e. softening, was induced by decamethonium, dimethylphenylpiperazine, and 2-ketoamyltrimethylammonium. 4. The involvement in these effects of ACh-binding groups with pharmacological properties similar to those of the "anionic sites" of nicotinic ACh receptors is suggested.

Acetylcholine↗
PubMed1989

The effect of etomidate pretreatment on cerebral high energy metabolites, lactate, and glucose during severe hypoxia in the rat.

Etomidate was compared with thiopental with respect to preventing loss of brain high energy metabolites and accumulation of lactate during 20 min of hypoxemia (Pa2 of 16-19 mmHg) in rats with unilateral carotid artery ligation. Male Sprague-Dawley rats, anesthetized with halothane and nitrous oxide (N2O) in oxygen were randomly assigned to one of six groups. A normoxic control group which received 70% N2O in oxygen, a hypoxia group received no iv drug treatment (hypoxia-N2O), and four iv drug treatment groups (N2O was replaced by 70% nitrogen at the start of drug administration). The iv drug groups were treated as follows: hypoxia-etomidate low dose (1 mg.kg-1 iv followed by an infusion at 0.35 mg.kg-1.min-1); hypoxia-etomidate high dose (1 mg.kg-1 then 1.3 mg.kg-1.min-1); hypoxia-thiopental low dose (15 mg.kg-1, then 1.5 mg.kg-1.min-1); and hypoxia-thiopental high dose (15 mg.kg-1, then 5 mg.kg-1.min-1). After hypoxia or a corresponding period in the normoxic group, the brains were frozen in situ for later biochemical analysis. Blood was obtained prior to and at the end of hypoxia and analyzed for glucose. Brain metabolite concentrations on the side ipsilateral to the ligated carotid artery in the normoxia-N2O group were adenosine triphosphate (ATP), 2.76 +/- 0.1, phosphocreatione (PCr) 3.88 +/- 0.12, lactate 2.34 +/- 0.16, and glucose 3.56 +/- 0.28 (mumole.g-1 wet weight, mean +/- SE). There was no significant decrease in ATP in any of the hypoxia groups. PCr decreased by 45% (compared to normoxia-N2O) in the hypoxia-N2O group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Prehospital pediatric endotracheal intubation performance review.

Pediatric prehospital care was reviewed over a one-year period to determine success rate, causes of unsuccessful attempts, and complications of performing endotracheal intubation. The Milwaukee County Emergency Medicine Technician-Paramedics (EMT-Ps) responded to 1467 pediatric (less than 19 years of age) patient calls. This accounted for 11% of the patients who received EMT-P care during the study period. Of the 63 patients requiring pediatric endotracheal intubation, 49 (78%) were successfully intubated. Of the 42 pulseless nonbreathing (PNB) patients, 39 (93%) were successfully Of the 21 patients judged to be in impending respiratory failure, 10 (48%) were successfully intubated. Common difficulties in intubating the PNB patient included inability to visualize the glottis and cords secondary to mucus and/or vomitus, use of inappropriately small endotracheal tubes, and accidental extubation during transport. Difficulties in intubating impending respiratory failure patients included patient resistance and seizure activity. We recommend that the EMT-P training curriculum include a review of these difficulties and that prehospital pediatric endotracheal intubation performance be monitored and reviewed with the EMT-Ps.

Adolescent↗
PubMed1989

CBC differential profile in distinguishing etiology of neonatal meningitis.

A retrospective study of 72 infants under four weeks of age with meningitis evaluated over almost four years was performed to determine the predictive value of the CBC differential ratio (% lymphocytes + % monocytes/% polymorphonuclear leukocytes + % band forms) profile in distinguishing those with bacterial from those with a nonbacterial etiology. Of 18 neonates with bacterial meningitis, all had a radio lower than one; of 54 neonates with aseptic or viral meningitis, 46 (85%) had a ratio greater than one. The difference between mean ratio values of the two groups was highly significant (P less than 0.001). A CBC differential ratio less than one was more sensitive (100%) in initially identifying neonates with bacterial meningitis than were other traditionally utilized parameters, eg, presence of fever (50%), ill appearance (50%), hypoglycorrhachia (61%), elevated CSF protein (55%), or CSF Gram-stained smear revealing pathogenic organisms (45%). Statistical analysis revealed that a CBC differential ratio less than 1.5 will accurately predict all cases of neonatal bacterial meningitis with a confidence of 99.95%. The CBC differential ratio is an accurate index for distinguishing neonates with bacterial meningitis from those with nonbacterial meningitis. Utilization of this parameter in conjunction with other traditional factors is efficacious in predicting outcome.

Blood Cell Count↗
PubMed1989

Accidental cocaine intoxication in a nine-month-old infant: presentation and treatment.

A case of a nine-month-old male who ingested cocaine is presented. The rarity of this type of ingestion, as well as the caretaker's denial of the presence of cocaine in the household, made rapid diagnosis of this infant's malady difficult. We present this case to alert physicians to the presentation and treatment of cocaine-intoxicated infants.

Accidents, Home↗
PubMed1989

Partial characterisation of the human erythrocyte antigen Pta.

Ghosts were prepared from erythrocytes positive for the rare blood group antigen Pta. Immunoblotting of the solubilised ghosts with anti-Pta located the antigen on a band with an Mr of 31,600, about 1,100 higher than that of sialoglycoprotein gamma. Binding to the same band was also observed when cytoskeleton preparations from Pt(a+) erythrocytes were immunoblotted with the antibody. Haemagglutination and immunoblotting experiments were consistent in demonstrating that the Pta antigen is not inactivated by treatment of intact erythrocytes with neuraminidase or trypsin but is destroyed by treatment with alpha-chymotrypsin, papain or pronase. The data indicate that the Pta antigen is carried on a 'new' erythrocyte membrane protein.

Blood Group Antigens↗
PubMed1989

Selective inhibition of nerve growth factor-stimulated protein kinases by K-252a and 5'-S-methyladenosine in PC12 cells.

K-252a, a protein kinase inhibitor isolated from the culture broth of Nocardiopsis sp., inhibits the nerve growth factor (NGF)-stimulated phosphorylation of microtubule-associated protein 2 (MAP2) and Kemptide (synthetic Leu-Arg-Arg-Ala-Ser-Leu-Gly) by blocking the activation of two independent kinases in PC12 cells: MAP2/pp250 kinase and Kemptide kinase. The NGF-stimulated activation of these kinases is inhibited in a dose-dependent manner following treatment of the cells with K-252a. Although these kinases also are activated by epidermal growth factor (EGF) and 12-O-tetradecanoyl-phorbol 13-acetate, K-252a has no inhibitory effect when these agents are used. Half-maximal inhibition of the activation of both kinases was observed at 10-30 nM K-252a. K-252a was shown to directly inhibit the activity of MAP2/pp250 kinase and Kemptide kinase when added to the phosphorylation reaction mixture in vitro; however, half-maximal inhibition under these conditions was observed at greater than or equal to 50 nM K-252a. These data suggest that K-252a exerts its effects at a step early in the cascade of events following NGF binding. The effects of K-252a are similar to those reported for 5'-S-methyladenosine (MTA) and other methyltransferase inhibitors. Treatment of PC12 cells with MTA inhibited NGF-, but not EGF-mediated activation of MAP2/pp250-kinase (Ki greater than 500 microM). MTA, when added to the phosphorylation reaction mixture in vitro, directly inhibited kinase activity (Ki = 50 microM), suggesting that the effects of MTA may be the result of its action on protein kinases rather than methyltransferases.

Adenosine↗
PubMed1989

Failure of zinc gluconate in treatment of acute upper respiratory tract infections.

Zinc is a trace metal with in vitro activity against rhinovirus, the major etiologic agent in acute upper respiratory tract infections (URIs). A previous trial of zinc gluconate supported its efficacy in treating URIs, but the effectiveness of blinding was uncertain. We conducted a prospective randomized trial of zinc gluconate versus a taste-matched placebo of sucrose octaacetate. Lozenges containing either 23 mg of elemental zinc or placebo were taken every 2 h. Eleven URI symptoms were rated daily on a scale of 0 (not present) to 3 (severe). Duration of illness, reflected in the proportion of subjects remaining symptomatic on each day, was not significantly reduced (maximum difference of 12.6% on day 7, P = 0.09; 95% confidence interval, -6 to 31%) by either treatment. Severity of illness, assessed by using a summed severity score, was reduced incrementally by 7 to 8% on days 5 to 7 (P = 0.02) in subjects taking zinc. Adverse effects, mostly nausea and altered taste, were reported by 50% of subjects taking zinc. We conclude that while zinc gluconate may produce a small reduction in overall severity of symptoms, this is not clinically significant. Given the additional high incidence of adverse effects, zinc gluconate cannot be recommended for use in the treatment of acute URIs.

Clinical Trials as Topic↗
PubMed1988

Musculoskeletal status of men and women who entered a fitness programme.

The musculoskeletal status at entry into a fitness programme and the incidence of injuries during the first four months of the programme were evaluated in 991 men and women who were aged 20-63 years. At entry, about half of the subjects reported having received treatment for musculoskeletal ailments previously, or that currently they were experiencing musculoskeletal pain and/or discomfort, and about one-third of the subjects reported one or more movement limitations. New injuries during the first four months of the programme were reported by 38% of subjects, with an average duration of impairment of 3.8 weeks, and 43% of those who were injured sought medical treatment. The most frequent type, location, and cause of injury were "joint sprains/strains" (66%), the lower leg (70%), and jogging (33%), respectively. Musculoskeletal problems (previous treatment, current pain or discomfort or movement limitations) in the leg did not predict leg injuries during the programme, but back problems did predict back injuries. Age, sex, body mass index, a parental history of musculoskeletal disease, a sporting history, and the frequency of vigorous exercise during the first four months did not predict injury. The study emphasized: first, the vulnerability of previously-sedentary persons to musculoskeletal injury and the consequent need for care in the management of fitness programmes; secondly, the need for the evaluation of such programmes if they are to have a rational rather than an intuitive basis; and thirdly, the need for epidemiological research on the musculoskeletal system as a basis for systematic efforts, partly through education and ergonomics, to reduce wear and tear on the musculoskeletal system.

Adult↗
PubMed1988

Outpatient management of diabetic ketoacidosis.

An analysis of 63 pediatric diabetic patient visits to an emergency department for diabetic ketoacidosis was performed. Of 27 patients with a serum pH less than 7.20 or bicarbonate concentration less than 10 mmol/L (10 mEq/L) at admission, 25 (92%) had persistence of metabolic acidosis after three hours of outpatient therapy and were hospitalized. Of 36 patients with a serum pH greater than or equal to 7.20 or a bicarbonate concentration greater than or equal to 10 mmol/L (10 mEq/L) at admission, 34 (94%) had resolution of metabolic acidosis within three hours of initiating outpatient therapy and were discharged from the emergency department. The relapse rate in each group was similar. The initial serum glucose concentration accurately predicted duration of therapy necessary to resolve metabolic acidosis in the majority of patients discharged. Certain diabetic children can be treated for diabetic ketoacidosis with therapy administered in an outpatient setting. Most patients with an initial serum pH of 7.20 or higher or a bicarbonate concentration of 10 mmol/L (10 mEq/L) or higher will experience resolution of acidosis and tolerate feeding within three hours of initiating treatment.

Adolescent↗