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Biomedical subjects

J D White

Publications and source records attributed to J D White.

At least 127 records · Page 7Linked to original sources
PubMed1986

Increased enkephalin gene expression in the hippocampus following seizures.

Bilateral, recurrent seizures were induced in adult male rats by a unilateral, electrolytic lesion of the dentate gyrus hilus. This treatment led to a bilateral depletion of enkephalin-like immunoreactivity in the hippocampal mossy fibers by 12 hours (h) post-lesion, a rebound above normal levels by 24 h, a further rise by 4 days than a fall to control values by 10 days post-lesion. The mRNA for preproenkephalin was elevated in the granule cells by 3h post-lesion, reached a maximal 24-fold rise by 30 h then fell again to control values by 4-10 days post-lesion.

Animals↗
PubMed1985

Immediate transthoracic pacing for cardiac asystole in an emergency department setting.

This study was conducted to prospectively evaluate immediate transthoracic pacing in the emergency department for cardiac arrest patients presenting with asystole. All adult patients presenting over an 11-month period to a university teaching hospital with asystole following nontraumatic cardiopulmonary arrest received immediate transthoracic cardiac pacing. In these 48 patients, electrical capture was achieved in 23% and mechanical capture in 17%. With subsequent intraventricular administration of epinephrine and sodium bicarbonate, the percentage of responders increased to 48% and 33%, respectively. This is a statistically significant improvement in both electrical and mechanical capture rates (P less than 0.001) as compared with historical controls in whom transthoracic pacemakers were employed several minutes into the resuscitation. In mechanical responders, blood pressure never exceeded 50 mm Hg and could not be sustained for over 2 minutes. Immediate transthoracic pacing was temporarily effective at restoring myocardial electrical and mechanical activity in a substantial number of asystolic patients. Although there were no survivors, the improved electrical and mechanical capture rates with early use of transthoracic pacing is encouraging. Future studies of transthoracic pacing in the prehospital setting appear warranted.

Adult↗
PubMed1985

Levothyroxine ingestions in children: an analysis of 78 cases.

A series of 78 cases of accidental levothyroxine ingestion in children (less than 12 years old) with treatment limited to ipecac-induced emesis and a single oral dose of activated charcoal is presented. No patient received any form of dialysis or hemoperfusion, propylthiouracil, cholestyramine, steroids, or serial doses of oral activated charcoal. Propranolol was used in one case despite the absence of clinical manifestations of toxicity. Only four children developed symptoms, limited to modest fever (38.3 degrees C), supraventricular tachycardia (120-176 beats/min), lethargy, irritability, vomiting, diarrhea, and abdominal pain. Peak T4RIA values in three patients were 32.8, 30.0, and 26.4 micrograms/dl, respectively, and two of these patients remained asymptomatic. Initial therapy for acute levothyroxine ingestions in children can be safely limited to routine gastrointestinal decontamination. Hospitalization or prophylactic treatment with propranolol, propylthiouracil, corticosteroids, cholestyramine, or extracorporeal detoxification are unnecessary in the early asymptomatic phase.

Charcoal↗
PubMed1985

ACEP and academics.

Explore the source record for details and available documents.

Education, Medical↗
PubMed1985

Placement accuracy of percutaneous transthoracic pacemakers.

Experience has shown that the frequency of electrical capture of the heart with percutaneous transthoracic pacemakers is disappointingly low. The authors sought to determine whether the accuracy of ventricular placement could help to explain this observation. Six approaches were used in each of twenty adult patients who were examined at autopsy. Three parasternal approaches used the fifth intercostal space (5ICS). One pacing wire was inserted immediately to the left of the sternum along the parasternal line (5ICS-PS), one wire was inserted 4.0 cm to the left of the midsternal line (5ICS-4), and the third wire was inserted 6.0 cm to the left of the midsternal line (5ICS-6). All parasternal needle insertions were directed medially, dorsally, and cephalad toward the second right costrochondral junction at an angle of 30 degrees to the skin. Three subxiphoid approaches were performed through the left xyphocostal notch at an angle of 30 degrees to the skin. One pacing wire was directed toward the right shoulder (SXRS), one toward the sternal notch (SXSN) and one toward the left shoulder (SXLS). Accuracy of ventricular placement was assessed at autopsy. The success rates for the three parasternal approaches were as follows: 5ICS-PS = 0.85; 5ICS-4 = 0.80; 5ICS-6 = 0.90. For the three subxiphoid approaches success rates were as follows: SXRS = 0.25; SXSN = 0.50; SXLS = 0.65. All three parasternal approaches had higher success rates than the SXRS approach (P less than 0.05). In addition, the 5ICS-PS and 5ICS-6 approaches were more successful than the SXSN approach (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Autopsy↗
PubMed1985

Comprehensive toxicology screening in the emergency department: an aid to clinical diagnosis.

An audit of 2,641 toxicology requests from the Georgetown University Hospital Emergency Department from 1981 through 1984 was conducted to assess the contribution of toxicology laboratory results to the clinical evaluation of the intoxicated patient. Positive findings were obtained in 80% of the patients tested. Ethanol was the most common intoxicant, accounting for 48% of all positive results and an average serum concentration of 250 mg/dl. Multiple drug use was documented in 28% of the patients with positive results; some ingested as many as six substances. Women were more likely than men to be polydrug users. A comparison of laboratory findings with diagnosis based on history and examination for 76 patients revealed that the laboratory provided additional information on the nature of the intoxication two-thirds of the time. Our conclusion is that the toxicology laboratory offering a broadly based screening service when properly utilized by the emergency department staff can aid in establishing an accurate diagnosis and provide a guide to therapy in the intoxicated patient.

Adult↗
PubMed1985

Recognition of psychological and cognitive impairments in the emergency department.

Ninety-six patients presenting to a university hospital emergency department were screened before triage for psychological symptoms or cognitive impairment using the General Health Questionnaire (GHQ) and Mini-Mental State examination (MMS). Charts were reviewed for demographic information and emergency physicians' recognition of psychological symptoms or cognitive dysfunction. Of the patients studied, 38% had positive results on the GHQ, and 18% had positive results on the MMS. Psychological symptoms or cognitive impairments were recognized by the emergency physicians in only 8% of those with positive GHQ results and 6% of those with positive MMS results. The usefulness of screening measures for psychological symptoms and cognitive impairment of emergency department patients is discussed.

Cognition Disorders↗
PubMed1985

Injuries associated with percutaneous placement of transthoracic pacemakers.

Injuries associated with the percutaneous placement of transthoracic pacemakers are poorly documented. We prospectively sought to determine any injuries associated with various placement routes. Six different approaches were used in each of 20 adult patients examined at autopsy. Three parasternal approaches utilized the fifth intercostal space (5ICS). One pacing wire was inserted immediately to the left of the sternum along the parasternal line (5ICS-PS), one pacing wire was inserted 4 cm to the left of the midsternal line (5ICS-4), and the third wire was inserted 6 cm from the midsternal line (5ICS-6). All parasternal needle insertions were directed medially, dorsally, and cephalad toward the right second costochondral junction at an angle of 30 degrees to the skin. Three subxiphoid approaches were inserted through the left xyphocostal notch at an angle of 30 degrees to the skin. One pacing wire was directed toward the right shoulder, one toward the sternal notch, and one toward the left shoulder (SXLS). Injuries were assessed by autopsy, postmortem coronary angiography, and stereoscopic radiography. The 5ICS-PS approach resulted in fewer injuries when compared to all other approaches. Because previous work has demonstrated that the 5ICS-PS, 5ICS-6, and SXLS approaches are more accurate than the other approaches for transthoracic pacemaker insertion, the 5ICS-PS represents an approach that combines reasonable accuracy with the least likelihood for injury in the placement of percutaneous transthoracic pacing wires.

Adult↗
PubMed1985

Depolarization regulates adrenal preproenkephalin mRNA.

The regulation of neuropeptide gene expression has been investigated by using rat adrenal medullae grown in explant culture. After 3 days in culture the (now denervated) explants exhibited a 10-fold increase in leucine-enkephalin (leu-EK) content. Inhibition of protein synthesis with cycloheximide completely blocked the rise, whereas inhibition of RNA synthesis with actinomycin D or alpha-amanitin inhibited the increase by 50%. Inhibition of DNA synthesis with 1-beta-D-arabinofuranosylcytosine (cytosine arabinoside) had no discernible effect. To determine whether the rise in leu-EK was associated with an increase in specific mRNA coding for the opiate peptide precursor, blot hybridization analysis was performed. A single species of preproenkephalin mRNA was detected after various culture periods. The amount of mRNA increased 34-fold after 2 days in culture and 74-fold after 4 days. Consequently, the rise in mRNA levels preceded the increase in the amount of leu-EK. Depolarization of the adrenal medullae with either elevated potassium or veratridine, which prevents leu-EK accumulation, inhibited the increase in the amount of preproenkephalin mRNA. Moreover, the effect of veratridine was blocked by tetrodotoxin, suggesting that transmembrane sodium ion influx affects the increase in the amount of message. Our studies suggest that elevation of leu-EK in explanted (denervated) medullae is associated with increased amounts of mRNA coding for the peptide precursor and that these processes can be regulated by depolarization.

Adrenal Medulla↗
PubMed1985

Controlled comparison of radio wave regional hyperthermia and peritoneal lavage rewarming after immersion hypothermia.

Anesthetized random source dogs were cooled by ice-water immersion to a stable core temperature of 25 degrees C and subsequently rewarmed with normal saline peritoneal lavage (43 degrees C, 175 ml/kg/hr) or radio frequency electromagnetic-induced regional hyperthermia (4-6 watts/kg). The mean time required for core rewarming to 30 degrees C was 183 +/- 79 minutes for lavage and 58 +/- 13 minutes for radio wave therapy (p less than 0.01). There was no evidence of tissue damage with either modality. These data suggest radio wave regional hyperthermia is superior to peritoneal lavage for core rewarming of rapidly induced immersion hypothermia.

Animals↗
PubMed1985

Does fever or myalgia indicate reduced physical performance capacity in viral infections?

To study prospectively the effects of a brief febrile viral infection on parameters of muscle and circulatory function, seven volunteers were inoculated with sandfly fever virus and two control subjects with sterile saline. During but not after fever, decreased isometric and dynamic strength and endurance were recorded in various muscles. Impairment could not be explained by altered activities of relevant muscle enzymes in serum or muscle tissue or by altered muscle ultrastructure, but correlated with the severity of perceived symptoms, including myalgia, as rated by each subject. Compared to baseline, cardiac stroke volume was lower during and after fever. During fever, an increased heart rate maintained cardiac output at pre-inoculation values, whereas cardiac output fell in early convalescence. This decrease in cardiac output correlated significantly with the severity of fever. Thus, in brief viral infections a transient impairment of muscle performance capacity is correlated to subjective symptoms such as myalgia, rather than to fever, whereas a decreased cardiac output following such infections seems to be associated with the fever reaction.

Adult↗
PubMed1985

Presence and ontogeny of enkephalin and substance P in the chick ciliary ganglion.

The avian ciliary ganglion has been reported to contain both enkephalin and substance P in preganglionic terminals. However, extensive biochemical characterization of these antigens has not been completed. Using radioimmunoassays specific for Met5- and for Leu5-enkephalin and for substance P we identified immunoreactive substances in ganglionic extracts that comigrate on HPLC columns with standard Met5- and Leu5-enkephalin and with substance P. The ontogeny of Met5-enkephalin and substance P during embryogenesis was determined in ganglionic extracts and we found that the content of Met5-enkephalin in the ganglion reached a peak at embryonic stage 37 whereas the content of substance P in the ganglion reached its maximum in the adult.

Animals↗