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Biomedical subjects

C C McDonald

Publications and source records attributed to C C McDonald.

34 records · Page 2Linked to original sources
PubMed1971

Proton magnetic resonance studies of the ferredoxins from spinach and parsley.

Contact-shifted resonances have been detected in the pmr spectra of both oxidized and reduced forms of spinach and parsley ferredoxins. These resonances are assigned to the beta-CH(2) protons of four cysteine residues that are thought to bind the iron-sulfur redox center to the polypeptide chain. Temperature dependences of contact shifts reveal that the two iron atoms are antiferromagnetically coupled in both redox forms of each of these proteins. Thermal population of magnetic states gives rise to the contact shifts observed in the formally diamagnetic oxidized forms of these ferredoxins and accounts for the failure of contact shifts in the reduced forms exhibit to a Curie Law temperature dependence. It appears that the unpaired electron of reduced spinach and parsley ferredoxin is unequally distributed over the two iron centers. Valence states for the iron pairs of high-spin Fe(+3)-Fe(+3) and Fe(+2)-Fe(+3) for the oxidized and reduced forms, respectively, are compatible with the nmr results.

Electron Spin Resonance Spectroscopy↗
PubMed1970

Proton magnetic resonance study of ferredoxin from Clostridium pasteurianum.

Magnetic susceptibilities of both reduced and oxidized ferredoxin from Clostridium pasteurianum were obtained in solution. Whereas the reduced form exhibits a Curie law behavior, the magnetic susceptibility of oxidized ferredoxin in fact increases with temperature and suggests extensive antiferromagnetic exchange coupling between the component iron atoms. Contact-shifted resonances are observed for both forms of ferredoxin that are attributed to the beta-CH(2) protons of the eight cysteine residues. A model based on these results is presented.

Clostridium↗
PubMed1970

Proton magnetic resonance studies of Chromatium high-potential iron protein.

Contact-shifted nuclear magnetic resonances, arising from molecular paramagnetism, have been observed in both reduced and oxidized forms of the high-potential iron protein (HiPIP) isolated from Chromatium. Contact shifts of the reduced, formally diamagnetic form increase with temperature, indicating antiferromagnetic exchange coupling of the component iron atoms with thermal population of a magnetic state. In the oxidized form of HiPIP (formally S = 1/2), contact-shifted resonances attributed to the beta-CH(2) groups of two cysteine residues display approximate Curie law behavior, while contact-shifted resonances assigned to the two other cysteine residues continue to exhibit a temperature dependence characteristic of antiferromagnetic exchange coupling. A cluster model for the redox center of Chromatium HiPIP that appears compatible with the PMR and preliminary x-ray results(4, 11) is discussed.

Bacterial Proteins↗
PubMedDate not supplied

Medical control of mass gatherings: can paramedics perform without physicians on-site?

OBJECTIVE: Evaluate the experience of paramedic personnel at mass gatherings in the absence of on-site physicians. DESIGN: Retrospective review of patients evaluated by paramedics with emergency medical services (EMS) medical control. SETTING: First-aid facility operated by paramedics at an outdoor amphitheater involving 32 (predominantly rock music) concerts in accordance with the Chicago EMS System, June through September 1990. PARTICIPANTS: A total of 438 patients (< or = 0.1% on-site population) were evaluated. INTERVENTIONS: Presentations to the first-aid facility were viewed as if the patient was presenting to an ambulance. Transportation to an emergency department was strongly recommended for all encounters. Time from presentation to the first-aid facility until disposition was limited to 30 minutes in the absence of on-line [direct] medical control. Refusal of care was accepted. On-line [direct] medical control with the EMS resource hospital was initiated as needed. Off-line [indirect] medical control consisted of weekly reviews of all patients records and periodic site visits. RESULTS: Of the 438 patients, 366 (84%) refused further care, including 31 patients (7%) who refused advanced life support (ALS) level care. Seventy-two patients (16%) were transported; 37 by ALS and 35 by basic life support (BLS) units. On-line [direct] medical control was initiated in all ALS patients that were transported as well as for those who refused care. No known deaths or adverse outcomes occurred, based on lack of inquiries or complaints from the local EMS system, emergency departments receiving transported patients, law enforcement agencies, 9-1-1 emergency response providers, venue management, or security. No request for medical records from law firms have occurred. Problems noted initially were poor documentation and a tendency not to document all encounters (e.g., dispensing band-aids, tampons, earplugs, etc.). Concerns noted included: initial and subsequent vital signs, times of arrival, interventions, dispositions, and patient conditions of refusal. Specific problems with documentation of refusals at disposition included: appropriate mental status, speech, and gait; release with an accompanying family member or friend; and parental notification and approval of care for minors. There also was an initial tendency not to establish on-line [direct] medical control for ALS refusal or BLS medicolegal issues. CONCLUSIONS: The medical system configuration modeled after practices of prehospital care, demonstrates physicians did not need to be on-site when adequate EMS medical control existed with less than 30 minutes on-scene time.

Chicago↗
PubMedDate not supplied

A comparison of EMS continuing education for paramedics in the United States.

OBJECTIVE: To determine characteristics of continuing education programs for paramedics in large metropolitan areas, and to make recommendations for changes in the Chicago Emergency Medical Services (EMS) system. DESIGN: A survey of 95 metropolitan areas from each state in the United States. PARTICIPANTS: EMS medical directors, coordinators, and administrators. RESULTS: The survey population included 56 respondents. Within this group, 23% were from areas of 1 million people or more, 61% in areas with populations of 100,000 to 1 million and 16% from areas populated by < 100,000 people. Several system types were represented in the survey. In the systems surveyed, 98% mandate didactic continuing education requirements. Clinical continuing education was required by 34% of the systems. Ten systems (18%) awarded continuing education hours for documented in-field experience. This method did not have a specific structure by the majority of users. Both written and skills testing were used by most EMS systems to evaluate paramedic competency. No statistically significant differences (p > 0.05) could be found among population subgroups or EMS system types when evaluating the use of these various methods. CONCLUSION: EMS systems primarily use didactic sessions to meet their continuing education requirements. Nearly half of the systems requiring clinical continuing education use in-field credit to fulfill these requirements. In-field credit systems are poorly developed to date. This mechanism may be an effective alternative to usual clinical experiences for paramedics and deserves further investigation.

Clinical Competence↗
PubMedDate not supplied

Out-of-hospital use of neuromuscular-blocking agents in the United States.

OBJECTIVE: A national survey was mailed to state EMS directors to assess the current status of use of neuromuscular-blocking agents (NMBAs) by EMS systems across the United States. METHODS: Initial and second mailings were completed in early 1996 and 1997, respectively. RESULTS: Replies were received from all 50 (100%) states following the second mailing. Twenty-nine (58%) states use NMBAs. Eleven (22%) of the 29 use paralytic drugs only in aeromedical programs. Of the 18 states that use NMBAs in ground-based EMS systems, 11 (22%) use paramedic ambulance staffing exclusively. Registered nurses (RNs) or RN-paramedic teams comprised the majority of the remaining states' staffing configurations. The first reported date of implementation of use of NMBAs was 1985, and there has been a steady trend of additional states launching paralytic drug use over the last 12 years. CONCLUSION: This trend suggests that use of paralytic drugs by paramedics is becoming standard of care in many out-of-hospital systems.

Emergency Medical Services↗