Histaminergic activation of endogenous angiotensin II fails to inhibit alcohol intake in rats

Demonstrations that alcohol intake can be inhibited by pharmacological activation of the renal renin-angiotensin system (RRA) or injection of angiotensin II (ANG II) in rats led to this study of a role for endogenous ANG II in inhibition of alcohol intake in rats. Relatively small doses of histamine, above threshold for eliciting drinking of water and activation of the RRA, were injected SC in adult male Sprague-Dawley rats with access to 3.0% alcohol in 45-min one-bottle alcohol tests and in two-bottle tests in which alcohol and water were available at the midpoint of the 12-h dark phase. The 0.312 and 1.25 mg/kg doses of SC histamine elevated plasma renin activity to levels similar to those in rats that had just eaten food. Neither dose of histamine affected alcohol intake in one-bottle tests. A relatively large 10 mg/kg dose of histamine increased alcohol intake in a one-bottle test, but decreased alcohol intake and increased water intake in two-bottle tests. The inhibitory effect of the 10 mg/kg dose of histamine on alcohol intake was completely blocked by SC 10 mg/kg losartan, a selective AT1 angiotensin receptor antagonist. This 10 mg/kg dose of losartan given alone, however, failed to increase alcohol intake in one- or two-bottle tests. These results generally do not support a role for endogenous ANG II as an inhibitory physiological signal in the control of alcohol ingestion in rats, because histaminergic activation of RRA, using small but physiologically meaningful doses of histamine, failed to inhibit alcohol intake.

A case study of behavioral assessment and treatment of insect phobia

We assessed the academic performance of a 14-year-old boy with insect phobia in the context of feared stimuli. The dependent measure was math calculation rate across three conditions that varied therapist statements about the presence of crickets and the actual presence of live crickets. Subsequent treatment consisted of graduated exposure and contingent rewards for math problem completion. Assessment results indicated that the boy's performance was consistently low in the presence of live crickets but not when he was spuriously informed that crickets were present (the primary referral concern). Treatment results indicated no effect from exposure alone and a dramatic effect when exposure was combined with contingent rewards.

Missense translation errors in Saccharomyces cerevisiae

We describe the development of a novel plasmid-based assay for measuring the in vivo frequency of misincorporation of amino acids into polypeptide chains in the yeast Saccharomyces cerevisiae. The assay is based upon the measurement of the catalytic activity of an active site mutant of type III chloramphenicol acetyl transferase (CATIII) expressed in S. cerevisiae. A His195(CAC)-->Tyr195(UAC) mutant of CATIII is completely inactive, but catalytic activity can be restored by misincorporation of histidine at the mutant UAC codon. The average error frequency of misincorporation of histidine at this tyrosine UAC codon in wild-type yeast strains was measured as 0. 5x10(-5) and this frequency was increased some 50-fold by growth in the presence of paromomycin, a known translational-error-inducing antibiotic. A detectable frequency of misincorporation of histidine at a mutant Ala195 GCU codon was also measured as 2x10(-5), but in contrast to the Tyr195-->His195 misincorporation event, the frequency of histidine misincorporation at Ala195 GCU was not increased by paromomycin, inferring that this error did not result from miscognate codon-anticodon interaction. The His195 to Tyr195 missense error assay was used to demonstrate increased frequencies of missense error at codon 195 in SUP44 and SUP46 mutants. These two mutants have previously been shown to exhibit a translation termination error phenotype and the sup44+ and sup46+ genes encode the yeast ribosomal proteins S4 and S9, respectively. These data represent the first accurate in vivo measurement of a specific mistranslation event in a eukaryotic cell and directly confirm that the eukaryotic ribosome plays an important role in controlling missense errors arising from non-cognate codon-anticodon interactions.

Firearm violence. Impact on the patient and society

Firearm violence has reached an alarming level. The devastation that results from firearms has severe implications for the individual and society. Interventions for patients suffering firearm injuries must begin at the scene and continue through the many phases of illness including emergency care, critical care, intermediate care, rehabilitation, and home care. Nurses are in the prime position to coordinate the many phases of care, with the outcome being to incorporate the victim back into society. Prevention is the key to reducing firearm violence through awareness, education, and legislation.

A conditional-lethal translation termination defect in a sup45 mutant of the yeast Saccharomyces cerevisiae

Genetic studies have indicated that the product of the yeast SUP45 gene encodes a component of the translational-termination machinery. In higher eukaryotes, genes similar to SUP45 encode eukaryote release factor 1 (eRF1), which has a stop-codon-dependent peptidyl-release activity. Using a conditional-lethal mutant allele of SUP45 (sup45-2) and a combination of in vivo and in vitro approaches, we demonstrate that the product of the SUP45 gene (Sup45p or eRF1) is a factor required for translation termination in yeast. A homologous in vitro assay based on suppressor-tRNA-mediated readthrough of stop codons is used to show that a translating lysate from a sup45-2 mutant strain exhibits a termination defect when heated for short periods to greater than the non-permissive temperature (37 degrees C). This defect can be complemented with a purified preparation of Sup45p (eRF1) expressed in Eschericha coli. The termination defect in this strain appears to be due to an inability of the Sup45p protein to bind the ribosome, resulting in vivo in a reduced ability of Sup45p to release nascent polypeptides from the ribosome at the non-permissive temperature. Cell-free translation lysates from the sup45-2 strain do not show a defect in sense-codon translation at the non-permissive temperature. These data demonstrate that yeast eRF1 plays a role in translation termination and is functionally equivalent to its higher eukaryotic homologues.

Pharmacokinetics of amiloride after inhalation and oral administration in adolescents and adults with cystic fibrosis

STUDY OBJECTIVE

To compare the pharmacokinetics and systemic exposure of nebulized and oral amiloride in adolescents and adults with mild to moderate cystic fibrosis (CF).

DESIGN

Open-label, randomized, two-way crossover, single-dose pharmacokinetic study.

SETTING

University hospital clinical research unit.

PATIENTS

Nine adolescents and 10 adults with mild to moderate CF (forced expiratory volume in 1 sec > or = 50% predicted, Brasfield score > or = 15).

INTERVENTIONS

Patients received amiloride solution orally (10 mg of amiloride 1-mg/ml solution) and by inhalation [4.5 ml amiloride of 1-mg/ml solution in 12% saline (approximately 3.8 mmol/L) by DeVilbiss 646 nebulizer] during two study phases separated by a 7- to 28-day washout period. Serial blood and urine samples were collected for 48 and 72 hours, respectively.

MEASUREMENTS AND MAIN RESULTS

After oral dosing, the mean +/- SD maximum peak concentration (Cmax) was 20.6 +/- 10.0 ng/ml at 3.2 +/- 1.2 hours in adults and 21.7 +/- 4.88 at 2.9 +/- 0.6 hours in the adolescents. Mean area under the concentration-time curve (AUC) from time zero to infinity hours was 275 +/- 115 and 254 +/- 60 ng.hr/ml in the adult and adolescent groups; half-life was 16.0 +/- 0.7 and 13.4 +/- 1.4 hours, respectively. After nebulization, 14 of 19 subjects exhibited two concentration peaks (Cmax1 and Cmax2) with mean values of 1.57 +/- 1.67 ng/ml at 0.5 +/- 0.2 hours and 1.37 +/- 1.21 ng/ml at 4.0 +/- 1.0 hours for adults, and 1.49 +/- 0.99 ng/ml at 0.5 +/- 0.1 hours and 1.52 +/- 0.81 ng/ml at 3.3 +/- 0.5 hours for adolescents. Estimated mean +/- SD dose nebulized was 1.91 +/- 0.66 and 2.28 +/- 0.30 mg in the adult and adolescent groups, respectively. Mean +/- SD AUC from time zero to the last measurable plasma amiloride concentration after inhalation was 14.4 +/- 17.6 and 15.4 +/- 10.1 ng.hr/ml in the adults and adolescents. No significant adverse events occurred during the study. Pharmacokinetic parameters were not statistically different between the adolescent and adult groups by route of administration. However significant differences in peak amiloride concentration, AUC, and urinary amiloride excretion were evident when comparing oral versus inhalation administration within each group.

CONCLUSIONS

Mean amiloride plasma concentration peaks and AUC after inhalation were significantly lower than after oral dosing. In addition, the second amiloride plasma concentration peak may be due to oral ingestion of the nebulized amiloride, whereas the earlier Cmax1 after inhalation may be due to pulmonary absorption of amiloride. These results suggest that single-dose amiloride inhalation in patients with mild to moderate CF results in minimal systemic exposure compared with oral dosing, and that drug disposition is similar in adolescents and adults with CF.

Relax and try this instead: abbreviated habit reversal for maladaptive self-biting

We evaluated the effectiveness of an abbreviated habit reversal procedure to reduce maladaptive oral self-biting in an adolescent boy in residential care. Treatment involved a combination of relaxation and two competing responses. Results of a withdrawal design and two posttreatment medical evaluations indicated that the intervention eliminated the biting and the tissue damage it caused.

Benign prostatic hyperplasia specific health status measures in clinical research: how much change in the American Urological Association symptom index and the benign prostatic hyperplasia impact index is perceptible to patients?

PURPOSE

We assessed the relationship between changes in scores for the American Urological Association (AUA) symptom index and benign prostatic hyperplasia (BPH) impact index with patient global ratings of improvement in a large Veterans Affairs trial comparing different pharmacological therapies for BPH.

MATERIALS AND METHODS

The primary analyses compared absolute score changes from baseline with global ratings of improvement at 13 weeks for 1,218 men.

RESULTS

Subjects who rated themselves as being slightly improved had a mean decrease in AUA symptom index and BPH impact index scores of 3.1 and 0.4 points, respectively. However, the baseline scores strongly influenced this relationship.

CONCLUSIONS

These data provide guidance for investigators using the AUA symptom index and BPH impact index as outcome measures.

The products of the SUP45 (eRF1) and SUP35 genes interact to mediate translation termination in Saccharomyces cerevisiae

The product of the yeast SUP45 gene (Sup45p) is highly homologous to the Xenopus eukaryote release factor 1 (eRF1), which has release factor activity in vitro. We show, using the two-hybrid system, that in Saccharomyces cerevisiae Sup45p and the product of the SUP35 gene (Sup35p) interact in vivo. The ability of Sup45p C-terminally tagged with (His)6 to specifically precipitate Sup35p from a cell lysate was used to confirm this interaction in vitro. Although overexpression of either the SUP45 or SUP35 genes alone did not reduce the efficiency of codon-specific tRNA nonsense suppression, the simultaneous overexpression of both the SUP35 and SUP45 genes in nonsense suppressor tRNA-containing strains produced an antisuppressor phenotype. These data are consistent with Sup35p and Sup45p forming a complex with release factor properties. Furthermore, overexpression of either Xenopus or human eRF1 (SUP45) genes also resulted in anti-suppression only if that strain was also overexpressing the yeast SUP35 gene. Antisuppression is a characteristic phenotype associated with overexpression of both prokaryote and mitochondrial release factors. We propose that Sup45p and Sup35p interact to form a release factor complex in yeast and that Sup35p, which has GTP binding sequence motifs in its C-terminal domain, provides the GTP hydrolytic activity which is a demonstrated requirement of the eukaryote translation termination reaction.

Fast spin-echo MR in the detection of vertebral metastases: comparison of three sequences

PURPOSE

To examine the relative capabilities for the detection of vertebral metastases of three available fast spin-echo sequences: T1-weighted fast spin-echo, short tau inversion recovery (STIR) fast spin-echo, and T2-weighted fast spin-echo sequences with chemical shift selective saturation pulse fat suppression.

METHODS

Fourteen patients were evaluated prospectively over a 2-month period with T1-weighted fast spin-echo (four echo train, four acquisitions, 1 min 59 sec-2 min 37 sec). STIR fast spin-echo (16 echo train, four acquisitions, 2 min 30 sec-3 min 19 sec), and T2-weighted fast spin-echo (16 echo train, 4 acquisitions, 2 min 27 sec-3 min 16 sec). For all three pulse sequences, measurements were obtained of the signal intensities of normal marrow, abnormal marrow, fat, and noise posterior to the spine. Contrast-to-noise ratios were calculated for metastases in each case. Lesions were evaluated by three observers and rated for size, location, and conspicuity.

RESULTS

Signal intensities of fat, normal marrow, and noise were highest for T1-weighted fast spin-echo sequences. STIR fast spin-echo and fat-suppressed T2-weighted fast spin-echo had approximately similar fat-suppression capabilities. Though contrast-to-noise ratios were highest overall for STIR fast spin-echo, the finding was not statistically significant and lesion conspicuity was deemed better with fat-suppressed T2-weighted fast spin-echo and T1-weighted fast spin-echo images. Discrete lesions were well identified on all three pulse sequences.

CONCLUSION

Fast spin-echo sequences appear promising for the detection of vertebral metastases. Further work should be directed toward comparison with conventional spin-echo to determine whether fast spin-echo may replace conventional spin-echo sequences for evaluation of vertebral metastases.

A strategy for reducing russet in Red Fuji apples while maintaining control of black spot (Venturia inaequalis)

A trial at the Grove Research Station in southern Tasmania examined methods of protection against black spot and the effect of these treatments on russeting of Red Fuji apples. An untreated control was compared with sprays of cupric hydroxide (wettable powder and dry flowable forms, 2.5 g/L) and copper oxychloride (4.0 g/L), and with dithianon (wettable powder 5 g/L, or suspension concentrate 5.0 or 7.5 gL). All sprays were applied at greentip, and dithianon was also applied at 10-day intervals for 5 sprays (spring program). Copper treatments were followed, or not, by a spring program of thiram, and all treatments were with or without a following summer program of thiram. Control of black spot (95% fruit with no spot) was not achieved with copper sprays at greentip alone, although control was better than on the unsprayed treatment. All dithianon programs, and cupric hydroxide sprays followed by thiram, controlled black spot. No difference was found between formulations for either cupric hydroxide or dithianon. Copper oxychloride increased the incidence of severe russet to >50% compared with the unsprayed control (28.5%). All other treatments were satisfactory, with similar incidence of russet to the control treatment, and could be used in commercial practices.

The gdhA1 point mutation in Escherichia coli K12 CLR207 alters a key lysine residue of glutamate dehydrogenase

gdhA1 is a spontaneous mutant of Escherichia coli that causes complete loss of activity of the NADP-specific glutamate dehydrogenase (GDH) encoded by the gdhA gene. The gdhA1 mutational site has been identified by recombinational mapping, polymerase chain reaction (PCR) amplification and DNA sequencing, as an A to G transition at nucleotide 274 of the gdhA coding sequence, resulting in an amino acid change of lysine 92 to glutamic acid. The mutant enzyme forms hybrid hexamers with a wild-type GDH, providing a useful system for analysis of conformational integrity of mutational variants.

Fast spin-echo imaging of intracranial neoplasms

Our goal was to compare dual echo fast SE (FSE) T2-weighted MRI of intracranial neoplasms with conventional SE (CSE) images. In phase 1 of the study, CSE and FSE dual echo MR studies of 33 patients with intracranial neoplasms and 26 normal controls were separately interpreted by three neuroradiologists blinded to clinical history to ascertain differences in lesion conspicuity. The CSE and FSE images were read independently, in random order, with at least a 3 week interval between readings. In phase 2 of the study, CSE and FSE sequences were compared side by side by three neuroradiologists independently to evaluate lesion conspicuity and artifacts and to determine whether FSE would be an acceptable replacement for CSE imaging. Lesion detection was equivalent in 111 of 117 interpretations (94.9%). The CSE and FSE sequences were equivalent in detecting lesion-associated abnormalities (hemorrhage, calcium, mass effect, edema, and hydrocephalus) and in characterizing lesion size, margins, and signal intensity. Nonspecific T2 white matter hyperintensities were detected more often with CSE, while susceptibility artifacts were less conspicuous on FSE. Ventricular catheters, postoperative soft tissue and bony changes, and postradiation therapy changes were detected equally well on both sequences. In phase 2 of the study, lesion conspicuity and presence of artifacts were felt to be equivalent with the two sequences. The FSE sequences can serve as a rapid, feasible alternative to conventional CSE sequences for intracranial tumor detection.

Imaging of neurologic complications associated with pregnancy

The occurrence of a neurologic event during pregnancy or the puerperium may have devastating consequences for mother and child. It is imperative that the radiologist be familiar with the entities likely to be encountered in pregnancy so that these patients can be examined rapidly and efficiently. The importance of early and accurate diagnostic imaging is underscored by the fact that most patients are otherwise young and healthy, and prompt institution of appropriate therapy can result in complete recovery. In this report, we illustrate some of the more common neurologic complications that occur during pregnancy and the immediate postpartum period.

Fast spin-echo imaging of the brain

Fast spin-echo (FSE) imaging is a recently modified rapid-acquisition relaxation-enhanced technique that affords rapid magnetic resonance (MR) imaging while retaining true spin-echo (SE) contrast features. By manipulating factors such as echo train length, echo spacing, and order of phase encoding, dual-echo brain images currently may be obtained many times faster than with conventional SE techniques. The time advantage of FSE may be used simply to obtain images much more rapidly or to acquire images of much higher contrast or spatial resolution compared with conventional SE images in a comparable period of time. Lesion appearance and conspicuity are usually quite similar to those on conventional SE images, with the important exception of some hemorrhagic blood products, which may appear less conspicuous on FSE images because of reduced magnetic susceptibility effects. Another important difference is the bright appearance of fat on all routine FSE sequences (T1-weighted, proton-density, and T2-weighted), although this may be eliminated easily by using routine fat-suppression techniques. Recent applications of FSE include three-dimensional multislab imaging and high-resolution imaging with large-matrix, small-field of view, thin-slice, and multiple-excitation imaging parameters. FSE techniques appear quite promising for rapid MR imaging of the brain, and they have largely replaced conventional SE technique at some institutions.

Common carotid artery bifurcation: evaluation with spiral CT. Work in progress

To determine the utility of spiral computed tomography (CT) in evaluation of carotid artery stenosis, spiral CT images of 20 patients were compared with images obtained with conventional angiography (20 patients), ultrasound (US) (15 patients), and magnetic resonance (MR) angiography (six patients). The category of stenosis was determined for each internal carotid artery on the basis of the percentage of narrowing: mild = less than 30%, moderate = 30%-69%, and severe = 70%-99%. Occlusions were also noted. The degree of carotid stenosis determined with spiral CT correlated with that determined with conventional angiography in 92% of cases, with that determined with US in 97% of cases, and with that determined with MR angiography in 100% of cases. Calcifications and large ulcers were also well delineated. Spiral CT provided an accurate anatomic depiction of the carotid bifurcation, which could be helpful in preoperative evaluation. The major disadvantage of the technique was the need to postprocess data to remove veins, calcifications, and bone structures from the images.

The value of cerebral angiography in predicting cerebral ischemia during carotid endarterectomy

OBJECTIVE

Temporary occlusion of the carotid artery during endarterectomy can result in ipsilateral cerebral ischemia if collateral blood flow is insufficient. This requires placement of a shunt across the carotid bifurcation, which is associated with increased operative risk. We retrospectively analyzed preoperative cerebral angiograms and intraoperative electroencephalographic recordings to determine if ischemia during carotid endarterectomy could be predicted from angiographic data.

MATERIALS AND METHODS

The cerebral angiograms of 30 patients were examined. Collateral blood flow to the hemisphere on the side of surgery was determined to be present if both proximal segments of the anterior cerebral artery and the anterior communicating artery were visualized, or if filling and washout of the ipsilateral posterior cerebral artery could be seen. Collateral flow was determined to be inadequate if the anterior collateral system was incomplete, and if either the ipsilateral posterior communicating artery was absent or the posterior cerebral artery filled without washout. This information was compared with intraoperative electroencephalographic and shunting data.

RESULTS

Of 15 patients who had demonstrable collateral blood flow, 14 had stable electroencephalograms and did not require a shunt during surgery. In all 15 patients in whom no collateral flow to the ipsilateral hemisphere could be shown, electroencephalographic changes prompted placement of an intraluminal shunt.

CONCLUSION

We found that the angiographic determination of inadequate collateral cerebral circulation correlated strongly with the development of intraoperative ischemia. This implies that routine preoperative cerebral angiograms can be used to alert the surgeon to the potential need for shunt placement during carotid endarterectomy.

Hypertensive encephalopathy: findings on CT, MR imaging, and SPECT imaging in 14 cases

Hypertensive encephalopathy is a syndrome consisting of headache, seizures, visual changes, and other neurologic disturbances in patients with elevated systemic blood pressure. The purpose of this study was to analyze the imaging findings in 14 patients with hypertensive encephalopathy. CT (n = 13), MR (n = 12), and single-photon emission computed tomography (n = 2) examinations performed in these patients before and after resolution of symptoms were reviewed. Eight had the preeclampsia-eclampsia syndrome, and six had hypertensive encephalopathy due to other causes. CT and MR findings in all patients having these examinations were indicative of edema in the cortex and subcortical white matter in the occipital lobes. Two of the 14 patients also had similar findings in the cerebellum and frontal lobes. Single-photon emission computed tomography showed increased vascular perfusion adjacent to areas that appeared abnormal on CT and MR. The findings on the imaging studies resolved on follow-up examinations performed after the hypertension was corrected. Our results suggest that the radiologic findings associated with hypertensive encephalopathy may be useful in establishing the diagnosis in the appropriate clinical setting.