Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 20
Filter
1.
Inj Prev ; 9(1): 87-8, 2003 Mar.
Article in English | MEDLINE | ID: mdl-12642568

ABSTRACT

OBJECTIVE: To determine preschool children's response to a commercial back-up warning alarm in a mock setting of an automobile backing up. SETTING: Preschool parking lot in Albuquerque, New Mexico, USA. METHODS: With subjects acting as their own controls, 33 preschoolers were asked to walk behind a stationary vehicle twice. The first time, the control, no warning sound was emitted from the vehicle. The second time, the vehicle was placed in reverse gear triggering an alarm. Children's responses were recorded by a hidden video camera. Avoidance behavior by the child was considered a positive response. Location and distance to where the response occurred was measured. RESULTS: Thirty three children, 38-61 months, were studied. None responded to the alarm with avoidance behavior but 18 looked toward the vehicle or hesitated in their gait. CONCLUSION: Although over half of the children acknowledged the warning alarm, the device did not elicit avoidance behavior. Mere acknowledgment of the warning device would not prevent injury.


Subject(s)
Automobiles , Avoidance Learning , Child Behavior/psychology , Child, Preschool , Equipment Failure , Female , Humans , Male
2.
Pediatr Emerg Care ; 17(5): 329-33, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11673708

ABSTRACT

OBJECTIVE: To study emergency preparedness in public schools in a rural state. METHOD: Questionnaires were mailed to school nurses registered with the State Department of Education. Data collected included school nurse and staff training, school location, emergency equipment available, and Emergency Medical Service (EMS) access. RESULTS: Seventy-two percent of the surveys were returned after one or two mailings. They report little emergency training for both school nurses and school staff. Emergency equipment available varies widely: oxygen 20%, artificial airways 30%, cervical collars 22%, splints 69%. Equipment was more likely to be available in communities with populations of less than 200,000. Sixty-seven percent of schools activate EMS for a student and 37% for an adult annually. Eighty-four percent of schools have a less than 10-minute EMS response time. CONCLUSIONS: EMS activation to schools is a common occurrence. Schools are ill prepared to care for this acuity of student or staff as assessed by equipment and emergency training. Schools in smaller communities, however, are better prepared for emergencies.


Subject(s)
Emergency Medical Services/standards , Health Care Surveys , Rural Health Services/standards , School Nursing/standards , Schools/statistics & numerical data , Child , Disaster Planning/statistics & numerical data , Emergency Medical Services/supply & distribution , Emergency Treatment/instrumentation , Emergency Treatment/standards , Equipment and Supplies/supply & distribution , Humans , Inservice Training , New Mexico , Office Visits/statistics & numerical data , Rural Health Services/supply & distribution , School Nursing/education , Schools/standards , Surveys and Questionnaires
4.
Acad Emerg Med ; 7(1): 36-41, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10894240

ABSTRACT

OBJECTIVE: To compare pediatric patients transported by ambulance on more than one occasion (repeat) with those transported only once. METHODS: The authors analyzed pediatric (patient < 21 years old) transports for 1992-1995 by the ambulance service that provides 99% of transports for a non-innercity metropolitan area. Repeat transports were compared with single transports with regard to patient age, gender, chief complaint, and payment source. RESULTS: There were 17,448 transports involving 15,168 patients. Nearly half (49.0%) of the repeat transports involved patients in the oldest age category, 17 to 20.9 years, contrasted with 38.0% of single transports (p < 0.00001). Females comprised 51.4% of the repeat transports and 48.5% of the single transports (p = 0.0008). Traumatic complaints accounted for one-third (33.0%) of the repeat transports and half (51.1%) of the single transports (p < 0.0001). Chief complaints of the patients with repeat transports were more likely to be seizure, assault, abdominal pain, and respiratory problems, and less likely to be falls and motor vehicle-related complaints, than chief complaints of the patients with single transports (p < 0.0001). More than one-third (39.0%) of the repeat transports were funded by Medicaid, in contrast with 19.8% of the single transports (p < 0.0001). CONCLUSIONS: Compared with single transports, repeat transports were more likely to involve patients more than 16 years of age, female, and with a chief complaint of seizure, assault, abdominal pain, or respiratory distress, and more likely to be funded by public insurance (Medicaid). Repeat pediatric transports warrant further investigation. This information may be useful in designing interventions targeted at reducing emergencies and hence ambulance use.


Subject(s)
Ambulances/statistics & numerical data , Adolescent , Adult , Child , Child, Preschool , Emergency Service, Hospital/statistics & numerical data , Female , Humans , Infant , Male , Medicaid , New Mexico , United States
5.
J Asthma ; 37(8): 719-24, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11192237

ABSTRACT

Questionnaires given to school nurses were used to collect data regarding emergency asthma equipment and plans. Sixty-three percent reported <10 asthmatic visits per month, 25% reported 10-50, and 12% reported >50. Only 20% of school nurses reported that 75%-100% of asthmatic students had an emergency plan, and 24% did not know if asthmatic students had a plan. Only half of the nurses had input into the plan. Equipment varied: 16% had oxygen, 45% had peak flow meters, 0% had MDIs, and 20% had nebulizers available. Many asthmatic students lack emergency plans, and many school nurses are not involved in the plans.


Subject(s)
Asthma/therapy , Patient Care Planning , School Health Services , Emergency Nursing/instrumentation , Equipment and Supplies , Humans , Nebulizers and Vaporizers , Nurses
6.
Ann Emerg Med ; 35(1): 99-100, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10613953
7.
Acad Emerg Med ; 6(3): 232-8, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10192676

ABSTRACT

OBJECTIVE: To compare pediatric ambulance patients transported for chief complaints of suicide, assault, alcohol, and drug intoxication (SAAD) with pediatric patients transported for all other chief complaints. METHODS: An out-of-hospital database for the primary transporting service in an urban area was analyzed for patients 0-20 years of age from 1992 to 1995. Chief complaints by age, gender, and billing status were analyzed. RESULTS: There were 17,722 transports. The SAAD group comprised 14.9% of all transports (suicide attempt 1.6%, assault 5.9%, alcohol intoxication 3.2%, and drug abuse 4.2%). The proportion of transports due to SAAD increased with age: 0-11-year-olds (4.2%); 11-16-year-olds (17.5%); and 17-20-year-olds (20.3%) (p = 0.0001). Genders were equally represented in the overall group, while males comprised 52.6% of the SAAD transports (p = 0.032). In the SAAD group, the majority of transports for assaults (55.9%) and alcohol (58.8%) involved males, while females were the majority in transports for suicide (52.3%) and drug abuse (66%) (p = 0.0001). Reimbursement sources differed, with those in the SAAD group less likely to be reimbursed by private or public (Medicaid, government) insurance (p < 0.0001) compared with the overall group. CONCLUSIONS: A substantial proportion of pediatric emergency medical services transports are for high-risk conditions. This patient population differs from the overall group by age distribution and reimbursement source.


Subject(s)
Ambulances/statistics & numerical data , Emergency Medical Services/trends , Pediatrics/statistics & numerical data , Adolescent , Adult , Age Distribution , Alcoholism/epidemiology , Ambulances/economics , Child , Child, Preschool , Emergency Medical Services/statistics & numerical data , Female , Humans , Infant , Male , New Mexico/epidemiology , Pediatrics/economics , Pediatrics/trends , Retrospective Studies , Sex Distribution , Suicide, Attempted , Wounds and Injuries/epidemiology
8.
Ann Emerg Med ; 33(4): 388-94, 1999 Apr.
Article in English | MEDLINE | ID: mdl-10092715

ABSTRACT

STUDY OBJECTIVE: To determine whether implementation of a set of standardized pediatric telephone triage protocols results in consistent triage dispositions when applied by different operators. METHODS: A descriptive study with interrater comparisons was performed. Telephone interviews simulated the setting of a triage station in a university hospital-based pediatric emergency department. A mock parent presented 15 standardized respiratory cases in random order to 12 pediatric ED nurses. Nurses assigned patients' complaints to severity categories using 9 respiratory complaint protocols extracted from a commercially available pediatric telephone triage tool. Protocol selection and severity endpoints were recorded. Interobserver agreement among nurses was analyzed by the kappa statistic. Comparisons of operator characteristics and triage results were carried out by ANOVA. RESULTS: Interrater agreement in triage disposition among nurses was poor (kappa,.11; 95% confidence interval,.02 to.20). Protocol selection varied; the group used a mean of 3 different disposition-generating protocols per case. Disposition also varied, with up to 4 different severity endpoints per protocol in a given case. A post-hoc comparison of the mean disposition severity between nurses did not reach significance at an adjusted level (P =.04). Fifty-eight percent of the nurses felt confined by the protocols, and 42% admitted to at least 1 intentional deviation from them. CONCLUSION: It may not simply be assumed that the use of protocols will standardize care. This is particularly important in the case of triage, with current trends toward medical decisionmaking by less skilled providers with diminishing patient contact. Although triage protocols may be useful to guide clinical thinking, their consistency must be validated before they may be safely disseminated for general use.


Subject(s)
Decision Making , Decision Support Techniques , Triage , Adolescent , Child , Child, Preschool , Emergency Nursing , Female , Humans , Infant , Male , Nursing Assessment , Observer Variation , Respiratory Tract Diseases/classification , Respiratory Tract Diseases/diagnosis
9.
Prehosp Emerg Care ; 3(1): 7-10, 1999.
Article in English | MEDLINE | ID: mdl-9921732

ABSTRACT

OBJECTIVE: To compare pre-EMS intervention (bystander intervention) with EMS intervention (performed by fire department/EMS personnel) in the management of airway foreign bodies in children. METHODS: First-responding paramedic run reports for 1994 in the metropolitan area (city and county fire departments) pertaining to acute foreign body airway obstruction in children (aged 0-15 years) were reviewed. Data regarding age, gender, type of foreign body, method by which the airway was cleared, and mode of transportation were extracted. RESULTS: There were 103 runs with an age distribution as follows: 0-11 months 39.8%; 1-5 years 50.5%; and >6 years 9.7%. Fifty-eight (56.3%) involved males and 45 (43.7%) involved females. Eighty-five percent of the airways were cleared before EMS arrival. Thirty-eight percent were self-cleared by the child. The chance of airway clearance before EMS arrival increased with increasing age: 78% of the children aged 0-11 months, 88.5% of the children 1-5 years of age, and 100% of the children aged 6 years or older had their airways cleared before EMS arrival. Forty-four percent of the children were not transported, and 27% were transported by private vehicle. Coins and food were the two most common foreign bodies. CONCLUSION: The majority of airway foreign bodies were cleared before EMS arrival, especially in older children. This supports CPR training of new parents and the general population and has training implications for the EMS provider in managing the pediatric airway.


Subject(s)
Airway Obstruction/therapy , Ambulances , First Aid , Adolescent , Airway Obstruction/etiology , Bronchi , Child , Child, Preschool , Emergency Medical Services , Foreign Bodies/etiology , Foreign Bodies/therapy , Humans , Infant , Male , New Mexico , Treatment Outcome
10.
Ann Allergy Asthma Immunol ; 81(4): 322-5, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9809495

ABSTRACT

BACKGROUND: Acute asthma exacerbations can be life threatening and are recognizable to emergency medical service (EMS) personnel; however, the therapies and medications which these emergency service personnel can use to treat exacerbations are limited. Several studies have demonstrated the effective use of beta2-agonist therapy in the treatment of patients complaining of wheezing or dyspnea, yet few EMS personnel can administer them. OBJECTIVE: The purpose of this study was to determine what therapeutic interventions emergency personnel around the state of New Mexico could use when responding to a call for a severe asthma exacerbation. METHODS: Questionnaires were distributed over a period of three years, 1992-1994, to all Emergency Service Agencies in New Mexico. RESULTS: Eighty percent of the emergency medical personnel administer oxygen to patients experiencing acute asthma exacerbations. Seventeen percent of EMS personnel administer epinephrine, 4% administer steroids, and only 23% administer beta2 agonists. Only in more populated areas were EMS personnel allowed to administer beta2 agonists, and those personnel had to have at least intermediate-level training. Most emergency response teams in the state consisted of EMT Basics and provided only basic life support services. In rural New Mexico, transport to a hospital can often take over one hour, which left EMS crews feeling helpless. CONCLUSIONS: We conclude that due to the rural nature of New Mexico, EMS personnel should be trained in the use of beta2 agonists and allowed to administer them to patients with acute asthma exacerbations. In addition, standard protocols for the pre-hospital management of acute asthma exacerbations should be instituted.


Subject(s)
Asthma/therapy , Emergency Medical Technicians/statistics & numerical data , Emergency Treatment/methods , Acute Disease , Adrenergic beta-Agonists/administration & dosage , Albuterol/administration & dosage , Asthma/epidemiology , Emergency Medical Technicians/education , Emergency Medical Technicians/standards , Emergency Treatment/standards , Epinephrine/administration & dosage , Health Care Surveys , Humans , Nebulizers and Vaporizers , New Mexico/epidemiology , Rural Health , Surveys and Questionnaires , Theophylline/administration & dosage
11.
Prehosp Emerg Care ; 1(1): 28-31, 1997.
Article in English | MEDLINE | ID: mdl-9709317

ABSTRACT

OBJECTIVE: To compare the initial emergency medical services (EMS) prehospital assessment of medical and traumatic cardiopulmonary arrest in the pediatric patient with that of the Office of the Medical Investigator (OMI) and assess differences and implications for EMS training and prevention. DESIGN: Retrospective review of ambulance run forms with the OMI autopsy confirmations. SETTING: An urban EMS system and the state Office of the Medical Investigator. PARTICIPANTS: Patients 15 years of age or less who were treated by prehospital personnel from November 1, 1990, to October 31, 1991, for a medical or traumatic arrest. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Ambulance runs were reported for 2,586 pediatric patients. Of these, 42 (1.6%) had suffered arrests, with 32 (76%) medical arrests and ten (24%) traumatic arrests. Children 1 year of age or less accounted for 75% of the medical arrests, while children more than 1 year of age accounted for 80% of the traumatic arrests (p = 0.003). Overall mortality was 81%. When EMS prehospital assessments of medical and traumatic arrests were compared with autopsy reports, there was good agreement for sudden infant death syndrome (SIDS) (kappa = 0.70), but poor agreement for child abuse (kappa = 0.37). CONCLUSION: The authors found good agreement between EMS prehospital assessments and autopsy diagnoses for identifying pediatric SIDS, but child abuse was not well identified prior to autopsy.


Subject(s)
Cause of Death , Coroners and Medical Examiners , Data Collection/standards , Emergency Medical Technicians , Emergency Treatment/standards , Heart Arrest/diagnosis , Heart Arrest/etiology , Medical Records/standards , Adolescent , Age Distribution , Child , Child Abuse/statistics & numerical data , Child, Preschool , Emergency Medical Technicians/education , Female , Heart Arrest/mortality , Heart Arrest/prevention & control , Humans , Infant , Infant, Newborn , Male , New Mexico/epidemiology , Retrospective Studies , Sudden Infant Death/epidemiology , Urban Health
12.
J Asthma ; 34(6): 477-81, 1997.
Article in English | MEDLINE | ID: mdl-9428293

ABSTRACT

Many asthmatic children require assistance by emergency medical services (EMS) secondary to an acute asthma episode. What medication interventions are being utilized by EMS when responding to an asthma call for a child, and how does EMS management compare to home management given before ambulance arrival (pre EMS)? Sixty-one ambulance reports pertaining to acute asthma episodes in children aged 1 month to 15 years were collected and analyzed. There was no significant difference between likelihood to receive a beta 2-agonist nebulizer treatment pre-EMS arrival or by EMS. Oxygen was the most common EMS intervention.


Subject(s)
Asthma/therapy , Emergency Medical Services , Administration, Inhalation , Adolescent , Adrenergic beta-Agonists/administration & dosage , Adrenergic beta-Agonists/therapeutic use , Asthma/drug therapy , Child , Child, Preschool , Emergency Medical Technicians , Female , Humans , Infant , Infant, Newborn , Male , Nebulizers and Vaporizers , Oxygen/administration & dosage , Oxygen/therapeutic use
13.
J Emerg Med ; 14(5): 591-7, 1996.
Article in English | MEDLINE | ID: mdl-8933321

ABSTRACT

We present a case of a boy with potential high-voltage electrical injury. The patient sustained electrical injuries after his kite became entangled in a high-power electrical line. He presented to the emergency department with minor external electrical burns and frequent premature ventricular contractions (PVCs). The patient's clinical course is outlined. A discussion of the epidemiology of high-voltage electrical injury in children and the clinical management of electrical-injury-induced cardiac complications is provided. Although cardiac abnormalities are found in a significant proportion of high-voltage electrical injuries, the vast majority are evident within 12 h, resolve spontaneously within a few days, and cause little or no long-term sequelae. A small proportion of normal children have clinically benign PVCs.


Subject(s)
Electric Injuries/complications , Ventricular Premature Complexes/etiology , Child , Electrocardiography , Emergencies , Humans , Male
14.
Pediatr Emerg Care ; 11(3): 162-6, 1995 Jun.
Article in English | MEDLINE | ID: mdl-7651871

ABSTRACT

To compare and contrast retrospective versus concurrent quality of care review processes in a Level I Trauma Center, we conducted a retrospective chart review of all pediatric trauma admissions in 1990 (n = 113) and compared it to the concurrent trauma quality assurance program for the same time period. Twenty-four percent (24%) of the patients reviewed in the retrospective study were identified by filters and reviewed through the concurrent process. In both the retrospective and concurrent review process problems in medical care problems, documentation, social and preventive elements of the case, and overall assessment of the patients' care were described. Overall, we found less than 50% agreement between the two reviews. The retrospective review identified medical care issues in 64% of cases, compared with a 44% error rate noted in the concurrent review (P < 0.07). Reviewers were more likely to note the absence of appropriate documentation, and overall assessment of the patients' care in the retrospective process (P < 0.0001). The retrospective review also highlighted issues related to the prevention of the injury and the patients' social situation, which were not considered by the concurrent review. Overall, we found the concurrent review appropriate for case by case medical management, while the retrospective review was relevant to a systems approach to the care of the injured child. To obtain a complete picture of the care of injured children, we recommend 1) a portion of charts be reviewed retrospectively in addition to ongoing concurrent review; or 2) the concurrent review add filters that are specific to pediatric issues and overall system issues.


Subject(s)
Concurrent Review/standards , Pediatrics/standards , Quality of Health Care , Retrospective Studies , Trauma Centers/standards , Wounds and Injuries/therapy , Adolescent , Child , Child, Preschool , Documentation/standards , Female , Humans , Infant , Male , New Mexico , Sociology , Wounds and Injuries/prevention & control
15.
Ann Emerg Med ; 22(3): 512-6, 1993 Mar.
Article in English | MEDLINE | ID: mdl-8442537

ABSTRACT

STUDY OBJECTIVE: To determine if the mechanism of fatal childhood pedestrian injuries correlated with location, injury pattern, and age of the pedestrian and to determine ethnic differences in fatality rates. DESIGN: Retrospective review of state medical investigator reports and autopsies from 1986 to 1990. Logistic regression and chi 2 were used to test for statistically significant differences between the groups in our data set. TYPE OF PARTICIPANTS: New Mexican children, 0 to 14 years old fatally injured by moving vehicles. RESULTS: Sixty-four children died for an overall fatality rate of 3.8 (per 100,000). Native American children and children younger than 5 years experienced the highest fatality rates. Children younger than 5 years were more likely to be crushed under the wheels of a slow-moving vehicle in both a nontraffic and a traffic location, whereas older children were found more often to have died from injuries from a high-speed impact event in a traffic location (P < .001). Leg fractures (P = .001) and spinal fractures (P = .02) occurred more frequently in impact than crush injuries. CONCLUSION: Young children are at risk for a crush injury in both the traffic and nontraffic environment.


Subject(s)
Accidents, Traffic/mortality , Wounds and Injuries/mortality , Adolescent , Age Factors , Chi-Square Distribution , Child , Child, Preschool , Ethnicity , Female , Humans , Infant , Male , Minority Groups , New Mexico/epidemiology , Regression Analysis , Retrospective Studies , Wounds and Injuries/ethnology
16.
Pediatr Emerg Care ; 8(4): 179-83, 1992 Aug.
Article in English | MEDLINE | ID: mdl-1513725

ABSTRACT

Intraosseous and intravenous administrations of epinephrine were compared in newborn lambs. Plasma epinephrine levels were measured during each route of drug administration and used to calculate steady-state epinephrine clearance rate and to compare cardiovascular responses with plasma levels. Epinephrine was administered at a dose of 0.5 to 5 micrograms/kg/min. We observed first-order (linear) clearance kinetics by both routes of drug administration. The plasma epinephrine clearance rate was 186 +/- 17 ml/kg/min by the intraosseous route versus 174 +/- 11 ml/kg/min by the intravenous route. Dose responses were analyzed by computerized fit to a threshold model. The plasma epinephrine threshold, or lowest plasma level beyond which discernible increases in blood pressure occur, was slightly lower after intravenous than after intraosseous drug administration, 2.0 +/- 0.6 ng/ml versus 4.0 +/- 0.9 ng/ml of epinephrine. Both thresholds were within the ranges of plasma epinephrine levels that would be achieved at doses of 0.4 to 0.6 microgram/kg/min by either route. Other hemodynamic responses, including the maximum systolic blood pressure and degree of reflex bradycardia, were comparable. These results support the effectiveness of the intraosseous route for epinephrine administration.


Subject(s)
Epinephrine/pharmacology , Animals , Animals, Newborn , Bone Marrow , Dose-Response Relationship, Drug , Epinephrine/pharmacokinetics , Infusions, Intravenous , Infusions, Parenteral , Sheep
17.
Pediatr Res ; 31(5): 462-7, 1992 May.
Article in English | MEDLINE | ID: mdl-1351281

ABSTRACT

In adult animals, prolonged beta-agonist exposure leads to down-regulation of beta-adrenergic receptors and desensitization. Prior evidence from our lab suggests that this may not occur in developing animals. To study this, we measured the response to graded epinephrine infusion [2.7, 5.5, 13.6, 27.3 mumol/(kg.min), (0.5, 1.0, 2.5, 5.0 micrograms/(kg.min)], myocardial beta-agonist receptor density, and components of the receptor-cyclase system in newborn lambs before (n = 6) and after (n = 5) 3 d of continuous isoproterenol administration (2 micrograms/kg/min). beta-Adrenergic receptors were measured by radioligand binding. Epinephrine dose-response curves were analyzed for the threshold and slope for changes in mean blood pressure, systolic blood pressure, and heart rate versus plasma epinephrine levels. Despite 3 d of continuous isoproterenol infusion, we observed no desensitization of the hemodynamic response to epinephrine. There was a reduction in receptor density when expressed per membrane protein [155.3 +/- 19.5 (controls) versus 73.2 +/- 3.8 fmol/mg protein (agonist exposed), p less than 0.05], but no alteration in receptor density when expressed per g cardiac wet weight [258.8 +/- 39.9 (controls) versus 406.8 +/- 74.0 fmol/g wet weight (agonist exposed)]. There was no alteration in agonist affinity or in adenylyl cyclase activity after adjustment for membrane protein recovery. Prolonged beta-agonist infusion in newborn lambs does not desensitize hemodynamic responses to infused epinephrine. We propose that receptor regulation in developing animals is fundamentally different than in adult animals.


Subject(s)
Adrenergic beta-Agonists/administration & dosage , Receptors, Adrenergic, beta/drug effects , Animals , Animals, Newborn , Down-Regulation , Epinephrine/administration & dosage , Hemodynamics/drug effects , Infusions, Intravenous , Isoproterenol/administration & dosage , Myocardium/metabolism , Receptors, Adrenergic, beta/metabolism , Sheep
18.
Pediatr Ann ; 19(11): 659-67, 1990 Nov.
Article in English | MEDLINE | ID: mdl-2277733

ABSTRACT

It is the practitioner's responsibility to have a prepared office to aid the emergently ill child. Basic equipment and staff training are essential. The pediatrician and family practitioner are on the front lines of pediatric emergency care and, with minimal equipment and training, can serve a vital role in the initial stabilization of the critically ill child.


Subject(s)
Emergency Medical Services , Child , Equipment and Supplies , Family Practice/methods , Humans , Pediatrics/methods , Resuscitation
19.
Biochem J ; 207(3): 369-79, 1982 Dec 01.
Article in English | MEDLINE | ID: mdl-7165697

ABSTRACT

Maintenance of fibroblasts in 0.5% serum results in viable but non-proliferative cells that may be analogous to fibroblasts in vivo. The synthesis of proteoglycans by human embryo lung fibroblasts in Eagle's minimal essential medium with 0.5% newborn-bovine serum or with 10% serum has been compared. A similar amount of [35S]sulphate-labelled glycosaminoglycan per cell was secreted by fibroblasts in 10% or 0.5% serum. 35SO42-incorporation into sulphated glycosaminoglycans was enhanced in 0.5% serum when expressed per mg of cell protein, but [3H]glucosamine incorporation was decreased. The charge density of these glycosaminoglycans was not changed as determined by ion-exchange chromatography. It was concluded that decreased protein/ cell resulted in an apparent increase in 35S-labelled glycosaminoglycan synthesis/mg of cell protein, whereas decreased uptake of [3H]glucosamine resulted in a decrease in their glucosamine labelling. The proteoglycans secreted by fibroblasts in 0.5% serum were similar in glycosaminoglycan composition, chain length and buoyant density to the dermatan sulphate proteoglycan, which is the major secreted component of cells in 10% serum. Larger heparan sulphate and chondroitin sulphate proteoglycans, which comprise about 40% of the total secreted proteoglycans of cultures in 10% serum, were greatly diminished in the medium of cultures in 0.5% serum. The proteoglycan profile of medium from density-inhibited cultures in 10% serum resembles that of proliferating cultures, indicating that lack of proliferation was not responsible for the alteration. The dermatan sulphate proteoglycan, participating in extracellular matrix structure, may be the primary tissue product of lung fibroblasts in vivo.


Subject(s)
Fibroblasts/metabolism , Proteoglycans/biosynthesis , Blood , Cells, Cultured , Chromatography, Gel , Culture Media , Glucosamine/biosynthesis , Glycosaminoglycans/biosynthesis , Humans , Sulfates/metabolism
20.
J Cell Physiol ; 107(2): 271-81, 1981 May.
Article in English | MEDLINE | ID: mdl-7251685

ABSTRACT

The synthesis and turnover of sulfate-labeled glycosaminoglycans(35S-GAGs) has been investigated in diploid human embryo fibroblasts during in vitro cellular aging. With progressive subcultivation, there was a decreased incorporation of Na2(35)SO4 into 35S-GAGs released to the medium, but not into those accumulated at the cell surface. The composition of 35S-GAGs found in extracellular medium, cell surface (removable by gentle proteolysis), and intracellular compartments of the culture after 48-hr labeling did not change significantly with progressive subcultivation. Pulse-labeled 35S-GAGs moved from intracellular to surface and extracellular compartments more slowly in late-passage cultures. Addition of 1 mM beta-xyloside to both early- and late-passage cultures produced a ten-fold enhancement of extracellular 35S-GAG production without a concomitant increase in surface-associated 35S-GAG. We interpret the data of this study to mean that secreted and cell-surface glycosaminoglycans represent different pools and that cellular aging has its effect primarily upon the secreted pool of glycosaminoglycans. Late-passage fibroblasts demonstrate marked decreases in proliferation, culture density, fibronectin matrix, and gap-junction formation. Our results suggest that glycosaminoglycan synthesis and composition are not intimately related to these parameters.


Subject(s)
Cell Survival , Glycosaminoglycans/biosynthesis , Cell Compartmentation , Cell Line , Cell Membrane/metabolism , Cell Nucleus/ultrastructure , Cytoplasmic Granules/ultrastructure , Fibroblasts , Glycopeptides/biosynthesis , Humans , Hyaluronic Acid/biosynthesis
SELECTION OF CITATIONS
SEARCH DETAIL
...