Proenkephalin is processed in a projection-specific manner in the rat central nervous system

The biosynthesis and posttranslational proteolytic processing of proenkephalin was studied in three projection systems in the rat central nervous system--the caudate-putamen to the globus pallidus, the paraventricular nucleus of the hypothalamus to the median eminence, and the mossy fiber system of the granule cells of the hippocampus. By using the techniques of in vivo radiolabeling and sequential high-performance liquid chromatographic purification coupled with chemical modification, the biosynthesis of six radiolabeled [Met]enkephalin-containing peptides--[Met5]enkephalin, [Met5,Arg6,Gly7,Leu8]enkephalin, [Met5,Arg6,Phe7]enkephalin, metorphamide, peptide E, and BAM 18P--was followed. In each projection system, radiolabeled enkephalins were purified to constant radiochemical specific activity. However, the posttranslational processing of proenkephalin was found to differ between these three systems, as judged by the relative ratio of these peptides. These findings imply that specific, different physiologies and behaviors may be elicited by the enkephalins based upon the specific [Met]enkephalin-containing peptides that are cleaved from proenkephalin and released in synaptic terminal fields.

High-yield radiographic considerations for cervical spine injuries

A clinical and academic imperative has developed to define high-yield criteria for cervical radiography in the emergency department setting. Presented is a review of key literature, including discussions of epidemiologic and biomechanic considerations; previously derived criteria and their value; and the limitation of the radiograph as a diagnostic tool. We conclude that the identification of truly high-yield criteria will be defined in future prospective, multicenter studies.

Enkephalin biosynthesis and processing during lactation

The biosynthesis of three Met-enkephalin-containing peptides was studied in the hypothalamo-hypophysial system of normal and lactating female rats by the techniques of in vivo radiolabeling and sequential high-performance liquid chromatographic purification of radiolabeled peptides. Met-enkephalin biosynthesis was stimulated in the lactating animals; however, the products derived from the post-translational processing of the enkephalin precursor appeared to remain constant between the two states, as judged by the ratio of radioactivity present in Met5-enkephalin, Met5Arg6Gly7Leu8-enkephalin and Met5Arg6Phe7-enkephalin. Additionally, 8-fold more radioactive enkephalin was harvested from the median eminence than the posterior pituitary. Measurement of preproenkephalin mRNA in the two states also revealed an increase during lactation. All of these data suggest a physiologically important role for the enkephalins in the regulation of anterior pituitary function.

In vivo biosynthesis and transport of oxytocin, vasopressin and neurophysin from the hypothalamus to the spinal cord

The biosynthesis of oxytocin, vasopressin and their associated neurophysins were studied in the projection from the paraventricular nucleus of the hypothalamus to the spinal cord in individual freely-moving adult male rats. Neuropeptide biosynthesis was studied in vivo by the delivery of [35S]cysteine through stereotaxically implanted indwelling cannulae using an osmotic minipump delivery system. Following the appropriate chase times, the neural lobe and spinal cord segments T1-T4 and T12-L2 were removed from fresh tissue; in addition, the nucleus of the solitary tract was punched from frozen coronal sections. The radiolabeled peptides were purified from the tissue homogenates by sequential linear and exponential gradient elution from reverse-phase high performance liquid chromatography columns. This approach has allowed us to purify radiolabeled oxytocin and vasopressin from both the upper and lower spinal cord. However, the kinetics of oxytocin and vasopressin biosynthesis appeared to be remarkably different, as judged by their differential labeling with different pulse and chase times. Additionally, the use of different chase periods following the pulse of radiolabel has allowed us to determine that oxytocin reaches the spinal cord via the fast component of axonal transport (greater than 8 mm h-1). Using immunoprecipitation and purification by high performance liquid chromatography, we were also able to purify radiolabeled neurophysins from spinal cord tissue homogenates. These results lend further support to a role for oxytocin and vasopressin in the modulation of autonomic nervous system function and to the role of the paraventricular nucleus as an integration center for endocrine and autonomic function.

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.

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.

Teratoma of the tongue: a case report and literature review

Teratomas of the tongue are extremely rare neoplasms, with only five reported cases in the literature. We report an additional case here and review the literature on this rare entity.

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.

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.

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.

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.

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)

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.

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.

Comparison of rewarming by radio wave regional hyperthermia and warm humidified inhalation

Anesthetized random source dogs were cooled by ice water immersion to a stable core temperature of 25 degrees C and subsequently rewarmed with warm humidified inhalation (43 degrees C, 450 cc of min ventilation X kg-1) or radio-frequency induction hyperthermia (4-6 watts X kg-1). The mean time required for core rewarming to 30 degrees C was 280 +/- 114 min for ventilation and 58 +/- 13 min for radio wave therapy (p less than 0.001). There was no evidence of tissue damage with either modality. These data suggest radio wave heating is superior to warm humidified inhalation therapy for core rewarming of rapidly induced immersion hypothermia.

Controlled comparison of humidified inhalation and peritoneal lavage in rewarming of immersion hypothermia

Random source dogs were anesthetized and cooled by immersion in ice water to a stable core temperature of 25 degrees C and subsequently rewarmed with either normal saline peritoneal lavage (43 degrees C, 175 ml/kg/h) or warmed humidified inhalation (43 degrees C, 450 ml/kg/min ventilation). The time required for core rewarming to 30 degrees C was 192 +/- 61 minutes for lavage and 331 +/- 96 minutes for inhalation therapy (P less than 0.03). These data suggest that peritoneal lavage is superior to inhalation therapy for core rewarming of rapidly induced immersion hypothermia.

In vivo biosynthesis and transport of oxytocin, vasopressin, and neurophysins to posterior pituitary and nucleus of the solitary tract

A growing body of literature suggests that oxytocin (OXY) and arginine-vasopressin (AVP), in addition to their neuroendocrine roles, may serve as neuromodulators within the central nervous system of mammals. The present study investigated the biosynthesis of OXY, AVP, and their associated neurophysins in the paraventricular nucleus of the hypothalamus (PVN) and the transport of these peptides to the neural lobe and the nucleus of the solitary tract (NTS) in the brainstem of the rat. Rats were cannulated bilaterally in the PVN, and 24 hr later a 2-hr pulse of [35S]cysteine was administered using an Alzet minipump delivery system. After a 10-hr chase period, the neural lobe was removed and the PVN and NTS were punched. Tissue homogenates were adsorbed to and eluted from octadecyl-silica cartridges and analyzed by linear high performance liquid chromatography (HPLC) gradient elution, chemical and enzymatic modification, and exponential gradient HPLC elution followed by linear HPLC gradient analysis using an ion-pairing buffer system. This rigorous approach has allowed us to identify 35S-labeled material which co-purifies with OXY and AVP from the PVN, neural lobe, and NTS samples. Specific transport of the nonapeptides to the NTS was demonstrated when a unilateral transection of the hypothalamic fibers resulted in a unilateral depletion of the radiolabeled peptides from the NTS samples. Additionally, each of the neurophysins was purified from the neural lobe and NTS samples after linear HPLC gradient analysis, ion-pairing buffer linear gradient analysis, then tryptic digestion followed by exponential gradient HPLC analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphological alterations in blood and bone marrow of ribavirin-treated monkeys

The antiviral drug ribavirin (1, beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) produced significant hematologic effects when administered to rhesus monkeys by intramuscular injection over 10 days in doses of 30 or 100 mg/kg/day. The monkeys developed dose-related progressive anemia and thrombocytosis associated with marrow erythroid hypoplasia and megakaryocyte hyperplasia. In addition, bone marrow examination revealed phagocytosis of erythroid elements by histiocytes; vacuolization of erythroid precursors, and to a lesser extent precursors of other cell types; and occasional erythroid precursors with megaloblastoid appearance. The alterations were transient and disappeared on discontinuation of the drug.

Consequences of schemata for attention, impressions, and recall in complex social interactions

A study was conducted to assess the effects of personality schemata on attentional allocation, impressions, and memory among observers of a complex social interaction. Subjects were first primed with schematic descriptions of an actor, and then they listened to an audiotape in which that actor and another participated in several separate conversations, with the primed actor either in the foreground or in the background. Other subjects could throw a switch to shift either actors' conversations into the foreground. As predicted, subjects in this last group shifted their attention away from the primed actor after determining that his behavior did not violate the schema they had been given and shifted their attention back when the primed actor acted in a schema-inconsistent manner. Analyses of all three attentional conditions revealed that the less attention subjects were able to pay to the primed actor, the more they relied on their schemata in making impression judgments, the more confident they were in the occurrence of schema-consistent "false alarm" behaviors, and the less confident they were in the occurrence of schema-inconsistent and schema-irrelevant behaviors. These results are discussed in terms of subject strategies in dealing with information overload when processing complex stimuli.

Transthoracic pacing in cardiac asystole

A total of 139 patients had transthoracic pacemakers introduced via a subxiphoid approach for asystole during advanced CPR in the emergency department of a large urban teaching hospital over a calendar year. Two groups were examined retrospectively, A) 34 patients who presented asystolic, and B) 99 patients who presented with ventricular fibrillation that became asystole. Age, sex, and etiologies for cardiac arrest were similar in both groups; there were no survivors. The mean duration of asystole before pacemaker insertion was 4 min (group A) to 7 min (group B). Temporary electrical capture was obtained in six patients from group B, but electrical-mechanical association could not be achieved in any of these patients.

Programmed macromolecular synthesis in regenerating karyoplasts

Conditions for the preparation, purification, and maintenance of karyoplasts which could regenerate to reform whole viable cells were defined. Results of biochemical analyses of such karyoplasts at various times during regeneration indicated that a reproducible biosynthetic program was followed. Thus, an examination of the polypeptides made during regeneration by two-dimensional gel electrophoresis showed that the pattern of radiolabeled polypeptides synthesized at each time studied was specific and was significantly different from that observed at other times during regeneration. Polypeptides associated with three major cellular fractions--nuclear, cytoskeletal-microtrabecular, and soluble--were among the most dramatically regulated molecules. Other polypeptides, such as the major components of microfilaments and intermediate filaments, were synthesized at relatively constant rates and were assembled into structures throughout regeneration. Likewise, microtubules appeared to be reformed throughout regeneration, even in the absence of identifiable centriole-associated organizing centers. Finally, analysis of DNA synthesis by autoradiography showed that, even when prepared from whole cells synchronized at the G1/S interface, karyoplasts could not begin making DNA until they had regenerated an almost complete complement of cytoplasm.

Consequences of schemata for attention, impressions, and recall in complex social interactions

A study was conducted to assess the effects of personality schemata on attentional allocation, impressions, and memory among observers of a complex social interaction. Subjects were first primed with schematic descriptions of an actor, and then they listened to an audiotape in which that actor and another participated in several separate conversations, with the primed actor either in the foreground or in the background. Other subjects could throw a switch to shift either actors' conversations into the foreground. As predicted, subjects in this last group shifted their attention away from the primed actor after determining that his behavior did not violate the schema they had been given and shifted their attention back when the primed actor acted in a schema-inconsistent manner. Analyses of all three attentional conditions revealed that the less attention subjects were able to pay to the primed actor, the more they relied on their schemata in making impression judgments, the more confident they were in the occurrence of schema-consistent "false alarm" behaviors, and the less confident they were in the occurrence of schema-inconsistent and schema-irrelevant behaviors. These results are discussed in terms of subject strategies in dealing with information overload when processing complex stimuli.

Hypothermia: the Bellevue Experience

All adult patients (102 cases) presenting to Bellevue Hospital Medical Center over a calendar year (1978) with core temperatures less than 35 C were studied. Statistically significant correlations between hypothermia and mortality were identified according to mental status, hypoxia, hypotension, hyperamylasemia, duration and severity of hypothermia, and history of exposure and alcohol ingestion. Mortality could not be predicted on the basis of season, age (if greater than 40 years old), sex, presence of infection, or presenting temperature (if greater than 26 C). Thyroid and adrenal function were not significantly altered. Of only nine diabetic patients, four died in ketoacidosis or hyperosmolar states. There were no cases of meningitis, and the incidence of "occult" bacteremia was less than 1%. Prolonged hypothermia was uniformly associated with profound underlying medical disease. In patients presenting with temperatures less than 26 C, 50% of deaths resulted from temperature-induced ventricular arrhythmias. Alcoholics hypothermic from exposure had excellent prognoses; however, temperatures less than 26 C were associated with a marked and statistically significant incidence of death.

Hantaan virus, aetiological agent of Korean haemorrhagic fever, has Bunyaviridae-like morphology

Spherical to oval particles with a unit membrane and subunit surface structure were demonstrated by negative-contrast staining of supernatant fluids of A-549 cell cultures infected with strain 76-118 of Hantaan virus. The particles had an average diameter of about 95 nm, with a range of 80 to 110 nm. Similar particles were isolated by buoyant density fractionation in sucrose gradients. In four separate experiments, infectivity cosedimented with 95 nm particles at buoyant densities from 1.15 to 1.18 g/ml. Immunoaggregation of the virions was specifically produced by antisera obtained after Hantaan virus infection of man and rabbit. The known physicochemical and morphological properties of these particles are compatible with those generally reported for the Bunyaviridae family of viruses.

Effect of flunarizine on canine cerebral cortical blood flow and vascular resistance post cardiac arrest

Twelve dogs were anesthetized and instrumental for determination of CVP, arterial pressure, intracranial pressure, left atrial pressure, and frontal cerebral cortical blood flow (CCBF) by the thermal method. A catheter was introduced into the venous return of the cerebral confluence to allow determination of cerebral A-V oxygen saturation differences. The animals were placed on cardiac bypass using a circuit from the right atrium to the pulmonary artery and a second circuit from the left ventricular apex to the left femoral artery. A heat exchanger was used to maintain a constant blood temperature of 37 C in the output of the left side bypass circuit. All animals were heparinized during bypass. Ventricular fibrillation was induced after completion of the bypass surgery. Two dogs served as controls. Pre-arrest determinations of hemoglobin, glucose, CCBF, and cerebral A-V oxygen differences were taken. Full circulatory arrest was carried out for 20 minutes by shutting off the cardiac bypass. Resuscitation was achieved by resumption of bypass perfusion. Acid-base balance was corrected quickly, and pre-arrest perfusion pressure was achieved and maintained for 90 minutes. All pressure parameters were monitored continuously. All pre-arrest determinations were repeated at 20, 40, 60, and 90 minutes post resuscitation. Five dogs were treated with 6 microgram/kg flunarizine administered IV drip over 10 minutes immediately post reperfusion. Five dogs were not treated post arrest. Treated animals had a prompt return of CCBF rates equal to or greater than pre-arrest flow, which persisted throughout the period of post-arrest observation. Untreated animals had markedly reduced CCBF and increased resistance. CCBF uniformly proceeded to near zero flow by 90 minutes. The ICP was not significantly altered by treatment.