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Biomedical subjects

J R Hoffman

Publications and source records attributed to J R Hoffman.

At least 91 records · Page 5Linked to original sources
PubMed1994

Dietary supplementation and improved anaerobic performance.

In the present study, the effects of an increased daily dose of a dietary supplement (ATP-E, 0.2 g.kg-1.day-1) on Wingate test performance were examined in 12 men (21 +/- 1.6 years) prior to and following 14 days of supplement and placebo ingestion. A double-blind and counterbalanced design was used. Results revealed higher (p < .007) preexercise blood ATP (95.4 +/- 10.5 mumol.dl-1) for the entire group following 14 days of ATP-E ingestion compared to placebo measures (87.6 +/- 10.9 mumol.dl-1). Mean power (667 +/- 73 W) was higher (p < .008) after 14 days of ATP-E ingestion versus placebo (619 +/- 67 W). Peak plasma lactate was lower (p < .07) after 14 days of ATP-E ingestion (14.9 +/- 2.8 mmol.L-1) compared to placebo (16.3 +/- 1.6 mmol.L-1). These data suggested that the improvement in 30-s Wingate test performance in this group may be related to the increased dose of ATP-E.

Adenosine Triphosphate↗
PubMed1993

Effect of hypertonic sodium bicarbonate in the treatment of moderate-to-severe cyclic antidepressant overdose.

The objective of this study was to characterize the effect of intravenous hypertonic sodium bicarbonate (NaHCO3) administration in patients with moderate-to-severe cyclic antidepressant (CA) overdose. We reviewed charts of all 91 patients given the diagnosis of CA overdose in the University of California Los Angeles (UCLA) Emergency Medicine Center (EMC), who either died in the EMC or were admitted to the medical intensive care unit (MICU), and who received NaHCO3 in the EMC between 1980 and 1988. Twenty-four other patients with the same EMC diagnosis were admitted to the MICU during this period but did not receive NaHCO3. The response of blood pressure, electrocardiographic parameters, and mental status to serum alkalinization with NaHCO3 were evaluated. Major morbidity and mortality were recorded for all patients. Hypotension was corrected within 1 hour in 20 of 21 (96%) patients, QRS prolongation corrected in 39 of 49 (80%), and mental status improved in 40 of 85 (47%). There was one death, in a patient who was moribund on arrival to the EMC. No complications were attributable to the administration of NaHCO3. NaHCO3 seems to improve hypotension and normalize QRS duration rapidly in most patients treated, and improve mental status changes in almost one half. Serum alkalinization with NaHCO3, in conjunction with appropriate supportive care, seems to limit major morbidity and mortality effectively in patients with serious CA overdose.

Adolescent↗
PubMed1992

Expression of alpha-cardiac and alpha-skeletal actin mRNAs in relation to innervation in regenerating and non-regenerating rat skeletal muscles.

The expression of alpha-cardiac and alpha-skeletal actin mRNA in regenerating muscle was examined. Changes in mRNA levels were analyzed in autografted extensor digitorum longus (EDL) muscles in rats using alpha-isoform specific synthetic oligonucleotides and beta-actin cDNA as probes. After autografting, the expression of alpha-cardiac actin mRNA was induced; concomitantly that of alpha-skeletal actin mRNA was reduced. The pattern of alpha-actin mRNA expression appeared to be similar to that seen in embryonic skeletal muscle. In order to evaluate the effects of innervation on alpha-actin mRNA expression in regenerating muscle, nerveless, standard, and nerve-intact autografted muscles were examined. More complete innervation facilitated the recovery of alpha-skeletal actin mRNA to control levels, but had little effect on the amount of alpha-cardiac actin mRNA. We found that regenerating muscle shows that embryonic pattern of alpha-actin mRNAs in the early stage and concluded that the recovery of alpha-skeletal actin mRNA expression to the adult pattern is influenced by innervation, while alpha-cardiac actin mRNA expression is nerve independent.

Actins↗
PubMed1992

Oxygen consumption following exercise of moderate intensity and duration.

To study the effects of exercise intensity and duration on excess postexercise oxygen consumption (EPOC), 8 men [age = 27.6 (SD 3.8) years, VO2max = 46.1 (SD 8.5) ml min-1 kg-1] performed four randomly assigned cycle-ergometer tests (20 min at 60% VO2max, 40 min at 60% VO2max, 20 min at 70% VO2max, and 40 min at 70% VO2max). O2 uptake, heart rate and rectal temperature were measured before, during, and for 1 h following the exercise tests. Blood for plasma lactate measurements was obtained via cannulae before, and at selected times, during and following exercise. VO2 rapidly declined to preexercise levels following each of the four testing sessions, and there were no differences in EPOC between the sessions. Blood lactate and rectal temperature increased (P < 0.05) with exercise, but had returned to preexercise levels by 40 min of recovery. The results indicate that VO2 returned to resting levels within 40 min after the end of exercise, regardless of the intensity (60% and 70% VO2max) or duration (20 min and 40 min) of the exercise, in men with a moderate aerobic fitness level.

Adult↗
PubMed1992

Low-risk criteria for cervical-spine radiography in blunt trauma: a prospective study.

STUDY HYPOTHESIS: Cervical-spine radiography does not need to be performed on selected blunt trauma patients who are awake, alert, nonintoxicated, do not complain of midline neck pain, and have no tenderness over the bony cervical spine. STUDY POPULATION: One thousand consecutive patients seen in the UCLA Emergency Medicine Center with a chief complaint of blunt trauma, for whom cervical-spine films were ordered and for whom prospective data questionnaires were completed. METHODS: Clinicians completed data forms for each patient before radiograph results were known. Data items included mechanism of injury, evidence of intoxication, presence of cervical-spine pain and/or tenderness, level of alertness, presence of focal neurologic deficits, and presence of other severely painful injuries unrelated to the cervical spine. Physicians were also asked to estimate likelihood of significant cervical-spine injury. RESULTS: Twenty-seven patients with cervical-spine fracture were among the 974 patients for whom data forms were completed. A number of findings were statistically more common in the group of patients with fracture than without, but no single or paired findings identified all patients with fracture. All 27 patients with fracture had at least one of the following four characteristics: midline neck tenderness, evidence of intoxication, altered level of alertness, or a severely painful injury elsewhere. Three hundred fifty-three of 947 (37.3%) patients without cervical-spine fracture had none of these findings. CONCLUSION: Cervical-spine radiology may not be necessary in patients without spinous tenderness in the neck, intoxication, altered level of alertness, or other severely painful injury. A policy to limit films in such patients would have decreased film ordering by more than one third in this series, while identifying all patients with fracture.

Adolescent↗
PubMed1992

Quality assurance in the emergency department: evaluation of the ECG review process.

STUDY OBJECTIVE: To determine whether the review of emergency department ECGs by cardiologists contributes to the quality of patient care. STUDY DESIGN: We retrospectively analyzed ED ECGs and compared interpretations of the treating emergency physicians with those of the reviewing cardiologists. We then evaluated the ED care of patients with potentially significant ECG abnormalities that were not detected by the treating emergency physicians, as well as the care of patients whose ECGs were "flagged" by the reviewing cardiologists as needing follow-up. SETTING: University hospital. PARTICIPANTS: Four hundred consecutive ECGs obtained on ED patients. MEASUREMENTS AND MAIN RESULTS: Thirty-three of the 400 tracings had undetected potentially significant or critical ECG abnormalities; this adversely affected patient care in two cases. These two tracings were not flagged by the reviewing cardiologists. Thirteen ECGs were flagged by the cardiologists; patient care was not altered in any of these cases. CONCLUSION: Review of ED ECGs by cardiologists did not affect patient care at our institution.

Aged↗
PubMed1992

The empiric use of hypertonic dextrose in patients with altered mental status: a reappraisal.

STUDY HYPOTHESIS: Neither response to hypertonic glucose (D50W) nor presence of hypoglycemia can be reliably predicted by "typical" clinical findings (tachycardia, diaphoresis, and/or an available history of diabetes mellitus) in prehospital patients with altered mental status (AMS). POPULATION: Three hundred forty consecutive patients who received D50W for prehospital AMS as ordered by a university hospital paramedic base. METHODS: Review of prehospital records and tape recordings for all subjects to determine presence or absence of tachycardia, diaphoresis, and/or available history of diabetes mellitus at the time of field presentation, as well as response to D50W; final diagnosis was determined from emergency department charts in the 301 patients for whom they were available. RESULTS: Twenty-five patients (7.4%) had a complete response to D50W: 20 had hypoglycemia, diagnosis for one patient was unknown, and four had other causes of AMS. Three patients with an ED diagnosis of hypoglycemia had partial or equivocal responses to D50W, and five had no response. Complete responders were more likely than other patients to have diaphoresis (40% vs 13%, P less than .001) and available history of diabetes (52% vs 12.1%, P less than .001) but not tachycardia (36% vs 35.2%, P = NS). Nine complete responders, including five with hypoglycemia, had none of the three clinical signs. CONCLUSION: Although patients with hypoglycemia who respond to D50W are diaphoretic and have an available history of diabetes more often than other patients with prehospital AMS, 25% of complete responders who are hypoglycemic would not receive D50W if it were used only in patients with "typical" clinical findings. Selective use of D50W for AMS is desirable because very few patients respond, but it is only feasible with concomitant field use of a rapid test of serum glucose.

Allied Health Personnel↗
PubMed1991

The empiric use of naloxone in patients with altered mental status: a reappraisal.

STUDY OBJECTIVE: To determine whether clinical criteria (respirations of 12 or less, mitotic pupils, and circumstantial evidence of opiate abuse) could predict response to naloxone in patients with acute alteration of mental status (AMS) and to evaluate whether such criteria predict a final diagnosis of presence or absence of opiate overdose as accurately as response to naloxone. CASES AND SETTING: Seven hundred thirty patients with AMS who received naloxone for diagnostic or therapeutic purposes at the discretion of two large, urban, paramedic base teaching hospitals. METHODS: We reviewed paramedic run sheets and audiotapes on all 730 patients as well as available hospital records of all patients who demonstrated any response to naloxone to determine whether overdose was responsible for their clinical presentations. We also reviewed hospital records for a selected sample of naloxone nonresponders. MAIN RESULTS AND CONCLUSION: Only 25 patients (3.4%) demonstrated a complete response to naloxone, whereas 32 (4.4%) manifested a partial or equivocal response. Nineteen of 25 complete responders (76%), two of 26 partial responders (8%) (with known final diagnosis), and four of 195 non-responders (2%) (with known final diagnosis) were ultimately diagnosed as having overdosed. Respirations of 12 or less or the presence of any one of the three clinical findings as a group were each highly sensitive in predicting response to naloxone, and at least as sensitive as response to naloxone in predicting a diagnosis of opiate overdose. Selective administration of naloxone for AMS would have decreased the use of this drug by 75% to 90% while still administering it to virtually all naloxone responders who had a final diagnosis of opiate overdose.

Clinical Protocols↗
PubMed1991

Flumazenil: a new benzodiazepine antagonist.

Flumazenil is a recently discovered pharmacologic antagonist of the CNS effects of benzodiazepines. It acts by binding CNS benzodiazepine receptors and competitively blocking benzodiazepine activation of inhibitory GABAergic synapses. Animal studies and some human studies appear to demonstrate that flumazenil has weak intrinsic agonist activity; on the other hand, studies are inconclusive in demonstrating any inverse agonist effects of this agent. Evidence available suggests that flumazenil is well tolerated in human beings over a broad range of doses when given either orally or parenterally and does not produce serious adverse effects. In the setting of isolated benzodiazepine overdose, flumazenil is capable of completely reversing coma within one to two minutes, with this effect lasting between one and five hours. Repeat doses can be given safely to reverse recurrent effects of longer-acting benzodiazepines. Flumazenil is undergoing further evaluation by the Food and Drug Administration; should this drug receive approval, it is likely to be used in emergency departments as well as in a variety of other clinical settings. First, it could be used to effect rapid reversal of benzodiazepine-induced sedation that has been administered to facilitate medical, orthopedic, and surgical procedures, particularly in the event of inadvertent respiratory depression. Second, flumazenil might have a therapeutic role in the management of patients who have taken benzodiazepine overdoses. Although most of these patients can be managed successfully with supportive therapy alone, it is possible that the use of flumazenil may obviate the need for intubation and respiratory support in such patients and eliminate the possible adverse effects of even short-term endotracheal intubation. Finally, flumazenil could have both diagnostic and therapeutic value in patients with acute alterations of mental status of unknown etiology, particularly when possible drug overdose is a consideration. Because flumazenil appears to be specific in its antagonism of benzodiazepine-induced respiratory and CNS depression, it could be used empirically to confirm or exclude a role of benzodiazepines in the generation of mental status changes in the setting of overdose or coma of unknown origin. This in turn might obviate the need for further expensive (eg, computed tomography) and sometimes invasive (eg, lumbar puncture) diagnostic modalities. This might be particularly useful because there is nothing about benzodiazepine-induced coma that clearly distinguishes it from other causes of coma; thus, there are no signs or symptoms that may reasonably allow benzodiazepine overdose to be confirmed or eliminated on clinical grounds. Further studies will continue to define the ultimate use of this new agent.

Animals↗
PubMed1991

Serum amylase determination in the emergency department evaluation of abdominal pain.

We hypothesized that selective ordering of serum amylase in the emergency department (ED) is justified because (a) most patients with elevated amylase can be prospectively identified by characteristic clinical findings, and (b) the diagnosis of pancreatitis is usually predominantly based on clinical findings, since amylase is known to be neither sensitive nor specific for pancreatitis. The study population included 133 consecutive patients with a chief complaint of abdominal pain who had amylase drawn over a 2-week period at a university hospital ED. Patients with known major trauma were excluded. Emergency department and hospital charts were reviewed for selected clinical variables. The first part of our hypothesis was evaluated by comparing clinical characteristics of cases (elevated amylase) and controls; the second part was tested by comparing clinical findings and amylase in cases (patients diagnosed as having pancreatitis) and controls. We found that 17 patients with and 116 without elevated amylase were similar with regard to all clinical variables, and that no combination of findings could be used to predict elevated amylase. Amylase level was not predictive of an ultimate diagnosis of pancreatitis, which was, however, strongly related to classical clinical findings. Pancreatitis risk factors, epigastric pain and tenderness, radiation of pain to the back, and nausea and vomiting were each statistically more common in patients diagnosed as having pancreatitis (regardless of amylase) than in patients in whom pancreatitis was excluded despite elevated amylase; all patients diagnosed with pancreatitis had at least two of these. Thus, selective ordering of amylase on the basis of clinical characteristics fails to identify a large proportion of patients with elevated amylase.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Pain↗
PubMed1991

Anaerobic power responses to amino acid nutritional supplementation.

To examine the effect of a nutritional supplement (ATP-E) on high intensity exercise performance, 23 physically active males volunteered to perform six Wingate Anaerobic Power tests. Tests were performed prior to and at 14 and 21 days during ATP-E or placebo ingestion. The experiment followed a double-blind and random-order design. Twelve subjects (responders, R) showed an increase in preexercise blood ATP on Day 14 of ATP-E ingestion compared to control measures. The remaining 11 subjects (nonresponders, NR) had no change in preexercise blood ATP. Peak power and mean power were unchanged for both R and NR subjects across the exercise tests, but R experienced a decrease (p < 0.05) in immediate post-exercise plasma lactate on Day 14 of ATP-E testing compared to their control measures. NR had no change in peak plasma lactate at any time during the study. The results suggest that short-term high intensity exercise performance was maintained in R with less reliance on anaerobic metabolism, and that response was evident following 14 days of ATP-E ingestion.

Adenosine Triphosphate↗
PubMed1990

Migration of myogenic cells in the rat extensor digitorum longus muscle studied with a split autograft model.

The ability of myogenic cells to migrate perpendicular to the long axis of freely autografted muscles was examined. Rat extensor digitorum longus muscles were divided, and one half was devitalized by repeated freezing in liquid nitrogen while the other half was kept viable in physiologic saline. The halves were reunited with sutures and grafted back into the original muscle bed. At intervals between 5 and 25 days the grafts were removed and examined histologically for the presence of myotubes within the devitalized region. Myotubes were first seen in the devitalized half 10 days postgrafting with the maximum number of myotubes observed after 12 to 15 days. These results indicate that myogenic cells are capable of migration perpendicular to the long axis of the muscle fibers in an autograft.

Animals↗
PubMed1990

Does paramedic-base hospital contact result in beneficial deviations from standard prehospital protocols?

We reviewed written and audio records of paramedic-base hospital radio contact to determine whether care differed from that suggested in standard prehospital care protocols. Records of all 659 contacts for seizure, syncope, abdominal pain, or altered mental state during 1987 (28.4% of all contacts) were scored for the use of standard therapies (such as intravenous access, oxygen, naloxone hydrochloride) and unanticipated therapies (intubation, nitroglycerin). Cases that involved unanticipated treatments were reviewed to determine whether they could have been prospectively identified by simple clinical findings. Standard therapies were used in the majority of patients. Unanticipated therapies were administered to 13 patients, all of whom had abnormal vital signs, diaphoresis, respiratory distress, or a second prominent symptom. Data suggest that protocols could replace radio contact for most patients and that the few who might benefit from radio contact can be easily identified. A 90% reduction in radio contacts in Los Angeles county could save $3 million each year.

Abdominal Pain↗
PubMed1989

Algorithm use in the treatment of pre-hospital ventricular fibrillation: an analysis of 160 cases.

In a series of 160 consecutive patients with pre-hospital ventricular fibrillation, outcomes were improved if base-station personnel precisely followed the initial 7 steps of standard VF algorithms. This improvement reached statistical significance regarding survival to hospital discharge (17% vs. 6%, P less than 0.05), and reflected a very strong trend with regard to initial resuscitation and admission to hospital (31% vs. 18%, 0.05 less than P less than 0.10). These measures of outcome were even more strongly related to field time, such that patients treated in the field for less than 15 min did far better than patients treated longer. While concordance with algorithms did not independently diminish field time in this study, this probably reflects the fact that paramedics had to establish base hospital contact and receive orders from base personnel in all patients; thus it is probable that allowing paramedics to treat patients in VF, using precise protocols, without prior communication with a base hospital, would diminish field time, and this might lead to even further improvement in patient outcome.

Adult↗