Biomedical subjects

M Brenner

Publications and source records attributed to M Brenner.

At least 181 records · Page 10Linked to original sources

PubMed1990

Ultrasound guidance improves the success rate of internal jugular vein cannulation. A prospective, randomized trial.

STUDY OBJECTIVE: To compare conventional versus ultrasound-guided internal jugular vein cannulation techniques. DESIGN: Patients were randomly assigned to receive either conventional or two-dimensional ultrasound-guided internal jugular vein cannulation. Patients who could not be cannulated with five or fewer passes by either technique, were crossed over to the other technique. SETTING: Clinical research unit in a tertiary care center. PATIENTS: All consecutive patients who required urgent or urgent-elective internal jugular vein cannulation during the study period. INTERVENTIONS: The two-dimensional ultrasound transducer imaged all cannulation attempts. For patients randomized to ultrasound guidance, the operator viewed two-dimensional ultrasound images, and received verbal guidance from the ultrasound technician. For patients randomized to the conventional arm, two-dimensional ultrasound images were recorded without visual or verbal feedback. MEASUREMENTS AND MAIN RESULTS: Two-dimensional ultrasound was significantly better than conventional guidance in reducing the number of failed site cannulations from 6/17 (35 percent), to 0/12 (0 percent), p less than 0.05. Two-dimensional ultrasound also reduced the mean number of passes required to cannulate the vein from 3.12 to 1.75 (p less than .05), and was also successful in six/six (100) of patients who failed cannulation by conventional means (p less than 0.05). CONCLUSIONS: Intensivists can increase successful internal jugular vein cannulation using ultrasound guidance. Two-dimensional ultrasound should be considered for patients difficult to cannulate or those at high risk of cannulation complications.

Catheterization, Central Venous↗

PubMed1990

Detection of renal blood flow abnormalities in septic and critically ill patients using a newly designed indwelling thermodilution renal vein catheter.

To evaluate alterations in renal blood flow in sepsis-induced renal failure, we developed and studied a percutaneously placed thermodilution renal blood flow catheter in eight critically ill patients. Para-aminohippurate extraction coefficients were decreased, supporting the need for renal vein sampling to determine CPAH in sepsis. Thermodilution and CPAH methods correlated strongly, confirming the reliability of this thermodilution method. Renal vascular resistance, an indicator of renal vascular function, remained unchanged throughout the bouts of sepsis. The fraction of total body arterial blood flow going to the kidneys rose significantly during recovery from sepsis. Glomerular filtration rate, which was reduced in four of seven septic patients, correlated with the fraction of total blood flow going to the kidneys. These results suggest that renal vascular abnormalities may be occurring during septic shock. Our study demonstrates that sepsis-induced renal dysfunction may occur despite normal ranges of total renal blood flow during shock.

Acute Kidney Injury↗

PubMed1990

A new method for measurement of airway occlusion pressure.

Airway occlusion pressure correlates with central respiratory drive. The airway occlusion pressure (P0.1) may be an excellent predictor of the ability of patients with obstructive lung disease to wean from mechanical ventilation. We describe a new method for measuring P0.1 using digitized signals generated from standard respiratory equipment and a computer program to automatically determine P0.1 values. The accuracy of this new method was tested by comparison with standard analog recorder methods using a mechanical lung model, in ventilated patients in an intensive care unit, and in normal volunteers. In all settings, excellent correlation was obtained between P0.1 measurements by the digital Servo and standard analog methods (r = 0.99). This new method permits accurate and automatic determination of P0.1 in ventilated patients using standard respiratory equipment. The rapid response and ease of use of this method should enable evaluation of a number of physiologic variables involved in respiratory control in ventilated and nonventilated patients.

Airway Resistance↗

PubMed1990

Efficacy of twice-daily dosing of econazole nitrate 1% cream for tinea pedis.

This study was conducted to determine the efficacy of twice-daily applications of econazole nitrate 1% for the treatment of tinea pedis within a typical podiatric practice. The study showed that twice-daily application of econazole nitrate 1% is an effective therapy and is especially successful at preventing immediate fungal recurrence.

Administration, Topical↗

PubMed1990

Effect of low-dose troleandomycin on glucocorticoid pharmacokinetics and airway hyperresponsiveness in severely asthmatic children.

Fifteen hospitalized asthmatic children (8 to 18 years old) completed a 2-week randomized, parallel, double-blind placebo-controlled comparison of combination methylprednisolone and placebo troleandomycin, prednisone and troleandomycin (P-TAO) or methylprednisolone-TAO (MPn-TAO). Troleandomycin (250 mg once daily or every other day) and glucocorticoid doses were reduced by a standard protocol. Symptom scores, blood chemistries, pulmonary function tests, airway response to methacholine, and glucocorticoid pharmacokinetics were compared. In each group, a steroid dose reduction of 50% was achieved without a deterioration in symptom scores. Methacholine response was unchanged in all five on methylprednisolone alone, but decreased 3-fold to 30-fold in two of five on combination P-TAO, and four of five on combination MPn-TAO. Troleandomycin decreased MPn clearance by an average of 62% but did not alter prednisolone clearance. Low-dose TAO combined with MPn has a significant effect on methylprednisolone clearance in children, an effect equivalent to that reported with higher dose TAO (1000 mg/d) therapy. In addition, this preliminary study suggests that TAO may decrease bronchial hyperresponsiveness to methacholine in severely asthmatic children.

Adolescent↗

PubMed1990

Pulmonary and acid-base assessment.

With increased technology, increased patient longevity, and burgeoning health care knowledge, pulmonary assessment of clients has become more complex, and nurses are now challenged to develop more comprehensive skills. These include a more focused patient history on selected clients as well as careful inspection, palpation, percussion, and auscultation. Additional techniques such as voice sounds provide the nurse with even more assessment data. An understanding of common pathologic pulmonary problems and their corresponding assessment findings as well as knowledge about acid-base imbalances will result in more effective professional nursing care.

Acid-Base Imbalance↗

PubMed1990

Thoracoscopic treatment of spontaneous pneumothorax using carbon dioxide laser.

In an effort to improve the success rate of the previously described thoracoscopic electrocautery ablation technique of spontaneous pneumothorax, the carbon dioxide laser was evaluated in 12 patients. The recurrent (5 patients) or persistent (7 patients) spontaneous pneumothoraces were caused by rupture of (1) blebs in 6 patients, (2) intrapulmonary apical type II bullae in 3 patients, and (3) diffuse bullous emphysema, type III, in 3. The air leaks were successfully sealed in all but 1 patient with ruptured type II bulla. Surgical specimen from this single failure suggested that the entire inner lining of the bullae must be thermocoagulated. This technical modification led to successful outcome in 2 subsequent cases. With the use of carbon dioxide laser, it was possible to treat not only small blebs but all types of bullae causing spontaneous pneumothorax. Laser thoracoscopy is effective and safe in treating spontaneous pneumothorax.

Adolescent↗

PubMed1989

A prospective, randomized, controlled trial of prednisone for dilated cardiomyopathy.

Although prednisone has been used to treat patients with idiopathic dilated cardiomyopathy, its efficacy has not been rigorously studied. We therefore randomly assigned 102 patients to either treatment with prednisone (60 mg per day) or a control group. At three months, improvement, defined prospectively as an increase in the ejection fraction of greater than or equal to 5 percentage points, was observed in 53 percent of the patients receiving prednisone and 27 percent of the controls (P = 0.005). The mean (+/- SE) ejection fraction increased 4.3 +/- 1.5 percentage points (from 17.9 +/- 1.0 to 22.2 +/- 1.6 percent) in the prednisone group, as compared with 2.1 +/- 0.8 percentage points (from 17.1 +/- 1.1 to 19.3 +/- 1.4 percent) in the control group (P = 0.054). All patients were categorized prospectively in two separately randomized subgroups. "Reactive" patients (n = 60) were those who had fibroblastic (n = 36) or lymphocytic (n = 2) infiltration or immunoglobulin deposition (n = 16) on endomyocardial biopsy, a positive gallium scan (n = 7), or an elevated erythrocyte sedimentation rate (n = 18). "Nonreactive" patients (n = 42) had none of these features. At three months, 67 percent of the reactive patients who received prednisone had improvement, as compared with 28 percent of the reactive controls (P = 0.004). Nonreactive patients did not improve significantly with prednisone (P = 0.51). After three months, reactive patients who received prednisone daily were switched to alternate-day therapy (60 mg every other day), and after six months the improvement seen earlier was no longer present. These data suggest that patients with idiopathic dilated cardiomyopathy may have some improvement when given a high dose of prednisone daily. However, the increases in the ejection fraction that we observed during prednisone treatment were small, their duration was limited, and the side effects were important. Overall, prednisone was judged to have only marginal clinical benefit, and should not be administered as standard therapy for dilated cardiomyopathy.

Cardiomyopathy, Dilated↗

PubMed1989

The cardiovascular response of normal humans to the administration of endotoxin.

Marked abnormalities in cardiovascular function accompany septic shock, and bacterial endotoxin is believed to be one of the principal mediators of these abnormalities. To evaluate the cardiovascular effects of endotoxemia in humans, we measured hemodynamic variables in nine normal subjects given an intravenous bolus dose of endotoxin (Escherichia coli, 4 ng per kilogram of body weight) and in six normal subjects given a bolus dose of saline, before and three hours after administration. All the subjects then underwent volume loading with normal saline (mean, 2217 ml) during the fourth and fifth hours after administration of the bolus, and the measurements were repeated. Three hours after the administration of endotoxin and before volume loading, the cardiac index had increased by 53 percent and the heart rate by 36 percent (both changes were significant; P less than or equal to 0.008), and the systemic vascular-resistance index had decreased by 46 percent (P = 0.004). After volume loading (five hours after the administration of endotoxin), the left ventricular ejection fraction decreased by 1 percent of the base-line value in the subjects given endotoxin, but increased by 14 percent in the controls (P = 0.008). The left ventricular end-diastolic and end-systolic volume indexes increased by 18 percent (P = 0.07) and 24 percent (P = 0.042), respectively. Left ventricular performance, as measured by the ratio of the peak systolic pressure to the end-systolic volume index, was depressed (a decrease of 0.90 in the subjects given endotoxin vs. an increase of 0.76 in the controls; P = 0.024). We conclude that the administration of endotoxin to normal subjects causes a depression of left ventricular function that is independent of changes in left ventricular volume or vascular resistance. The changes in function are similar to those observed in septic shock and suggest that endotoxin is a major mediator of the cardiovascular dysfunction in this condition.

Adult↗

PubMed1989

Rom transcript of plasmid ColE1.

The ColE1 Rom protein contributes to copy number control by affecting the rate of formation of a complex between RNA II, the precursor of the primer for DNA replication, and RNA I, a small RNA complementary to the 5' end of RNA II. Interaction of RNA I with RNA II can affect plasmid copy number by preventing primer formation. Although the RNA I and RNA II transcripts have been well characterized, the rom mRNA has not previously been detected. We have now identified the rom mRNA, and determined its start site both in vitro and in vivo. We also have found that the rom mRNA terminates at any of several sites, and that its synthesis is not autoregulated by the Rom protein. By using an internal standard RNA to estimate the efficiency of detection of the rom mRNA, its level was determined to be about 1 molecule per cell.

Bacterial Proteins↗

PubMed1989

Amantadine sulphate in treating Parkinson's disease: clinical effects, psychometric tests and serum concentrations.

Intravenous administration of amantadine has been shown to be a quick-acting and highly effective method of treating patients with Parkinson's disease. The duration of this therapeutic effect during long-term oral treatment has, however, remained controversial. Therefore, the effect of intravenous treatment was compared with long-term oral treatment over a period of 6 months. Clinical scores and psychometrically determined dexterity improved significantly during 10-day infusion therapy (200 mg amantadine sulphate/day). This improvement was successfully maintained by oral treatment (600 mg/day). A decrease in effectiveness was not observed. Reaction times were within the normal range for the age group involved and did not change significantly during the course of the study. Amantadine serum concentration during the infusion period ranged between 500 and 1000 micrograms/l and produced values nearly half as high as those obtained during oral treatment (600 mg/day). There was a constant relationship (quotient: 1.3) between serum and cerebrospinal fluid concentration. Considerable inter-individual variations were noted. A significant inter-individual correlation between serum concentration and clinical and psychological improvement was not discernible.

Administration, Oral↗

PubMed1989

Agonist and antagonist properties of benzazepine and thienopyridine derivatives at the D1 dopamine receptor.

Nine structurally related 1-phenyl-1H-3-benzazepine derivatives and two thienopyridines were tested for agonist and antagonist properties at the adenylate cyclase-coupled D1 dopamine receptor in homogenates of the striatum of the rat. The benzazepines SK&F 77434 and SK&F 82958, both of which contain a catechol ring, were agonists; the intrinsic activity of SK&F 77434 was similar to that of SK&F 38393, whereas SK&F 82958 was a full agonist. The remaining benzazepines inhibited the stimulation of adenylate cyclase by dopamine. Antagonist potency depended on the nature of the substituent at position 7 of the benzazepine molecule, 7-halogen compounds being the most potent. The Ki values, obtained from analysis of the antagonism of dopamine-stimulated adenylate cyclase, were significantly correlated with the Ki values for displacement of D1 ligands in binding experiments. Furthermore, antagonist activity of the resolved racemic benzazepine SK&F 83566 resided almost exclusively in the R-enantiomer. The thienopyridine derivatives SK&F 89641 and SK&F 89145 were partial agonists with greater efficacies than SK&F 38393.

Adenylyl Cyclase Inhibitors↗

PubMed1989

Platelet scintigraphy in cerebrovascular diseases.

The benefit of platelet scintigraphy using 99mTc-phytate as a method to detect atherosclerotic lesions in extracranial neck vessels was tested on 143 patients. 29 patients had an abnormal scan of the neck vessels. The scintigraphic results were critically evaluated, taking clinical observations and the angiograms performed on 88 patients into consideration. Platelet scintigraphy can be useful as an additional examination in some patients. Generally, however, the value and reliability of platelet scintigraphy must be seen as insufficient, making further prospective studies with histological examinations imperative.

Adult↗

PubMed1989

Use of steroids in pediatric asthma.

Steroids are necessary for treatment of chronic asthma. They are life-saving in many acute exacerbations and enable daily functioning free of wheezing and disability for the chronic asthmatic. The beneficial effect of steroids for asthma is increasingly thought to be due to their anti-inflammatory effect on hyperreactive airways. Attempts have been made to develop synthetic steroids to maximize the anti-inflammatory effect on the target tissue while decreasing adverse effects on other tissues. Inhaled steroids with potent topical and minimal systemic effects have been the most important breakthrough in this regard. Long-term follow-up studies for over ten years of beclomethasone have not shown serious local or systemic side effects. Intravenous or oral steroids are still needed for acute exacerbations, and prednisone may be needed in combination with inhaled steroids for the severe asthmatic. Treatment of this complex, variable disease with any type of steroid should be accompanied by objective measurements of benefit (pulmonary function) and risk (steroid side effects).

Administration, Inhalation↗

PubMed1988

Surface expression of only gamma delta and/or alpha beta T cell receptor heterodimers by cells with four (alpha, beta, gamma, delta) functional receptor chains.

Surface expression of TCR dimers by cells synthesizing three or four distinct types of receptor chains was analyzed. Cells containing intact gamma, alpha, and beta chains had only gamma delta dimers on the cell surface. In human PEER cells, addition of a functional alpha chain led to the loss of gamma delta dimer expression and expression of only alpha beta dimers. This result was not due to transcriptional down-regulation of the gamma or delta loci. In murine cells expressing all four chains, both gamma delta and alpha beta dimers could be demonstrated on a single cell. No other chain combinations (alpha gamma, alpha delta, beta gamma, or beta delta) were detected. Thus, there is stringent control of assembly and/or transport of TCR heterodimers, such that functional receptors consist only of alpha beta and gamma delta pairs, and no additional repertoire diversity is generated by cross pairing.

Antigens, Differentiation, T-Lymphocyte↗

PubMed1988

Changes in nocturnal sleep in Huntington's and Parkinson's disease.

There have been no reports of studies on nocturnal sleep or quantitative studies of sleep spindle density in Huntington's disease, whereas sleep in Parkinson's disease has been extensively reported. We therefore examined nocturnal sleep changes in patients with Parkinson's and Huntington's disease and compared them with a control group. The previously reported decrease in sleep spindle density was observed in patients with Parkinson's disease. The patients with Huntington's disease, however, had a significant increase in sleep spindle density, the nocturnal sleep pattern being normal in other respects when compared with the control group. This observation may provide a further diagnostic criterion in Huntington's disease.

Adult↗

PubMed1988

Splenic size on routine chest films in AIDS: diagnostic and prognostic significance.

Sixty-nine percent of AIDS patients show evidence of splenomegaly on their plain chest film. This splenomegaly is not related to severity of AIDS, to intravenous drug abuse or to any specific infection or neoplasm but correlates well with severity of anemia, pancytopenia, and thrombocytopenia. Increasing splenomegaly usually indicates worsening of AIDS. The triad of splenomegaly, interstitial lung disease sparing the bases, and very thin chest wall soft tissues is highly specific for the diagnosis of AIDS. The sensitivity of the plain film for diagnosing AIDS can be increased by including AIDS in the differential diagnosis of all patients with splenomegaly, intrathoracic lymphadenopathy, cachexia, or bilateral interstitial lung disease of unknown cause.

Acquired Immunodeficiency Syndrome↗

PubMed1988

Need for theophylline in severe steroid-requiring asthmatics.

Concern about side-effects of theophylline prompted us to investigate whether this drug could be eliminated from the multi-medication regimen of severe asthmatics. We studied patients with a demonstrated requirement for systemic steroids who were taking most other available anti-asthma medications in an attempt to reduce systemic steroids while maintaining clinical stability. Five in-patients, 12-15 years old, completed a double-blind, cross-over trial of theophylline vs placebo. All were stable for 4 weeks prior to the study with normal spirometry and mildly elevated lung volumes. Regular medications consisted of long-acting theophylline with levels between 12 mcg/ml and 16 mcg/ml, and prednisone 10-30 mg on alternate days. In addition, they were all taking inhaled metaproterenol, cromolyn sodium, atropine sulphate, and beclomethasone dipropionate four times daily (qid). Patients received either theophylline or placebo during two drug periods. All other medications were unchanged. Parameters measured were symptom score, number of extra respiratory treatments (prn RTs), increase in steroid dosage, and daily spirometry. During the placebo period, all five patients required increased steroids, daily spirometry decreased and three patients developed severe exacerbations unrelated to viral infection. A marked increase in symptom score occurred within 48 hr of discontinuing theophylline in all. These findings emphasize that theophylline is beneficial in a subset of severe asthmatics who cannot be controlled with all other available bronchodilators, cromolyn, and inhaled and systemic steroids.

Adolescent↗