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Biomedical subjects

B A Johnson

Publications and source records attributed to B A Johnson.

At least 19 recordsLinked to original sources
PubMed2006

Neonate with vein of Galen malformation and heart failure: serial changes in plasma B-type natriuretic peptide following endovascular embolization.

We report a neonate with vein of Galen malformation (VGM) who developed congestive heart failure (CHF) early after birth. Serial changes in plasma B-type natriuretic peptide (BNP) following an endovascular embolization procedure for VGM were mirrored in his clinical CHF status. The plasma BNP level markedly increased to 1800 pg/ml (normal, <100 pg/ml) in accordance with the severity of CHF. It rapidly decreased to 356 pg/ml during the first week after endovascular embolization for VGM. In the following 3 weeks there was an unexpected upward trend in plasma BNP despite echocardiography revealing normal biventricular function. After additional evaluation and treatment for CHF, BNP decreased again and the patient's clinical status concurrently improved. The patient was discharged with a normal BNP level. Monitoring serial plasma BNP provides valuable information regarding the need for additional evaluation or treatment of newborns with CHF and may be used to document improvement.

Central Nervous System Vascular Malformations↗
PubMed2006

Diskography: infectious complications from a series of 12,634 cases.

BACKGROUND AND PURPOSE: Diskography is commonly performed to investigate pain of suspected diskogenic origin. Although uncommon, diskitis is a feared complication of this procedure. We reviewed the incidence of diskitis and other infectious complications following diskography in a large busy outpatient practice and discuss technical aspects that may contribute to infection prevention. METHODS: We reviewed the electronic records of all diskograms obtained at our institution during a 12.25-year period, looking for all cases of procedure-related infection. All diskograms had been obtained by skilled and experienced procedural radiologists in dedicated spine-injection suites with specialized technical staff. RESULTS: There were 12,634 examinations performed on 10,663 patients for a total of 37,135 disk levels. Of the disk levels, 5981 were cervical; 3083, thoracic; and 28,071, lumbar. Two cases of confirmed lumbar diskitis and no cases of either cervical or thoracic diskitis were seen in our series. No other infectious complications were found. The incidence of diskitis was 0.016% per examination and 0.0054% per disk level. CONCLUSION: In skilled and experienced hands using proper technique, diskography is a safe outpatient procedure with an extremely low incidence of diskitis and other procedure-related infections.

Adolescent↗
PubMed2004

Aerosol cyclosporin therapy in lung transplant recipients with bronchiolitis obliterans.

The majority of patients who develop bronchiolitis obliterans, after lung transplantation, die within 2-3 yrs after onset since treatment with conventional immunosuppression is typically ineffective. A case/control study was conducted in lung transplant recipients with biopsy-documented bronchiolitis obliterans to determine whether aerosol cyclosporin use contributed to increased survival. The cases comprised 39 transplant recipients who received open-label aerosol cyclosporin treatment in addition to conventional immunosuppression. The controls were transplant recipients treated with conventional immunosuppression alone. There were 51 controls from the University of Pittsburgh Medical Center and 100 from a large multicentric database (Novartis Lung Transplant Database). Forced expiratory volume in one second expressed as a percentage of the predicted value was an independent predictor of survival in all patients with bronchiolitis obliterans. Cox proportional-hazards analysis revealed a survival advantage for aerosol cyclosporin cases compared to the Pittsburgh control group. A survival advantage was also seen when comparing study cases to multicentric controls. Aerosol cyclosporin, given with conventional immunosuppression to lung transplant recipients with bronchiolitis obliterans, provides a survival advantage over conventional therapy alone.

Administration, Inhalation↗
PubMed2003

Diagnostic properties of transbronchial biopsy in lung transplant recipients who require mechanical ventilation.

INTRODUCTION: Bronchoscopy with transbronchial biopsy (TBBx) and bronchoalveolar lavage is useful and safe for diagnosing acute rejection and infection in lung transplant recipients. However, its role is less well defined in determining the etiology of allograft dysfunction in the setting of respiratory failure necessitating mechanical ventilation. METHODS: We retrospectively identified 41 mechanically ventilated patients with respiratory failure in whom 42 TBBx were followed within a 10 day period by surgical lung biopsy (SLBx) to determine the sensitivity, specificity, and positive and negative predictive values of TBBx compared with SLBx. RESULTS: The sensitivity, specificity, and positive and negative predictive values of TBBx for all episodes of acute rejection and for significant episodes of acute cellular rejection were 53.3% and 36.0%; 91.7% and 94.1%; 94.1% and 90.0%; 44.0% and 50.0%, respectively. A significantly higher histologic grade was noted on SLBx compared with TBBx specimens obtained within a 10-day period (2.39 +/- 1.02 vs 0.97 +/- 0.11, p <or= 0.0001). Performing SLBx in this setting increased histopathologic diagnoses by 33% and resulted in treatment changes in 15 of 41 (37%) patients. CONCLUSIONS: Transbronchial biopsy has low sensitivity, high specificity, and high positive predictive value for diagnosing acute rejection. We found a significant tendency for TBBx to underestimate the presence and severity of clinically significant grades of rejection while simultaneously overestimating the presence of clinically insignificant rejection. Adding SLBx is valuable in lung transplant recipients with respiratory failure who require mechanical ventilation.

Acute Disease↗
PubMed2001

Perceptual correlates of neural representations evoked by odorant enantiomers.

Spatial activation patterns within the olfactory bulb are believed to contribute to the neural representation of odorants. In this study, we attempted to predict the perceptions of odorants from their evoked patterns of neural activity in the olfactory bulb. We first describe the glomerular activation patterns evoked by pairs of odorant enantiomers based on the uptake of [(14)C]2-deoxyglucose in the olfactory bulb glomerular layer. Using a standardized data matrix enabling the systematic comparison of these spatial odorant representations, we hypothesized that the degree of similarity among these representations would predict their perceptual similarity. The two enantiomers of carvone evoked overlapping but significantly distinct regions of glomerular activity; however, the activity patterns evoked by the enantiomers of limonene and of terpinen-4-ol were not statistically different from one another. Commensurate with these data, rats spontaneously discriminated between the enantiomers of carvone, but not between the enantiomers of limonene or terpinen-4-ol, in an olfactory habituation task designed to probe differences in olfactory perception.

Animals↗
PubMed2001

A fatigue clinic in a comprehensive cancer center: design and experiences.

Cancer-related fatigue is now the most prevalent symptom of cancer, occurring in 60-90% of patients. Fatigue has been identified by cancer patients as a factor influencing functionality and quality of life. Our objectives in developing a fatigue specialty clinic at The University of Texas M. D. Anderson Cancer Center were to improve our patients' quality of life by decreasing fatigue; educate health care providers, patients, and patients' families about cancer-related fatigue; develop an appropriate clinical and diagnostic evaluation for this symptom; correlate objective measures of fatigue with its clinical evaluation; and develop innovative treatment plans for cancer-related fatigue. This article describes the general clinic design and operations and the preliminary analysis of the first 40 patients evaluated in the fatigue clinic.

Adult↗
PubMed2001

Fatigue during preoperative chemoradiation for resectable rectal cancer.

BACKGROUND: The aim of this study was to evaluate the severity and patterns of fatigue during preoperative chemoradiation therapy for locally advanced rectal cancer and determine whether there are predictors for patients who develop severe fatigue. METHODS: Seventy-two patients with resectable rectal cancer received chemoradiation (total radiation dose, 45 gray/25 fractions to the pelvis; continuous infusion of 5-fluorouracil [300 mg/m(2)]). The Brief Fatigue Inventory (BFI), a measure that categorizes fatigue severity on a 0-10 scale, was administered weekly during treatment. Severe fatigue was defined as 7-10 on the "worst level of fatigue" item. Demographics, disease information, toxicities, and blood counts were collected. Descriptive statistics, repeated measure analysis of variance, and multiple regression were used to examine fatigue and its correlates. RESULTS: Fatigue increased in 67% of patients during chemoradiation (CTX/XRT). The mean fatigue score increased from 3.16 before treatment to 4.62 at the end of treatment. A significant linear trend suggested that fatigue progressively got worse during CTX/XRT (F = 16.497, P < 0.001). However, 18% of patients experienced severe fatigue before CTX/XRT; this was predicted by uncontrolled pain (r(2) = 0.321; F = 16.52; P < 0.001). During CTX/XRT, uncontrolled diarrhea was the only predictor for increased fatigue (r(2) = 0.182; F = 7.77; P < 0.01). Approximately one-third of patients had severe fatigue, which impaired their function at the end of CTX/XRT. CONCLUSIONS: Preoperative chemoradiation therapy for patients with rectal cancer was associated with progressive fatigue during therapy. Based on identified predictors for fatigue, more active pain management before CXT/XRT and bowel management during CTX/XRT might reduce cancer-related fatigue in these patients.

Adult↗
PubMed2001

Fingertip injuries.

The family physician often provides the first and only medical intervention for fingertip injuries. Proper diagnosis and management of fingertip injuries are vital to maintaining proper function of the hand and preventing permanent disability. A subungual hematoma is a painful condition that involves bleeding beneath the nail, usually after trauma. Treatment requires subungual decompression, which is achieved by creating small holes in the nail. A nail bed laceration is treated by removing the nail and suturing the injured nail bed. Closed fractures of the distal phalanx may require reduction but usually are minimally displaced and stable, and can be splinted. Open or intra-articular fractures of the distal phalanx may warrant referral. Patients with mallet finger cannot extend the distal interphalangeal joint because of a disruption of the extensor mechanism. Radiographs help to differentiate between tendinous and bony mallet types. Most mallet finger injuries heal with six to eight weeks of splinting, but some require referral. Flexor digitorum profundus avulsion always requires referral. Dislocations of the distal interphalangeal joint are rare and usually occur dorsally.

Persons with Disabilities↗
PubMed2001

Combining ondansetron and naltrexone reduces craving among biologically predisposed alcoholics: preliminary clinical evidence.

RATIONALE: Previously, we have reported that the combination of ondansetron (a 5-HT3 antagonist) and naltrexone (a mu opioid antagonist) appears to act synergistically at improving the drinking outcomes of early onset alcoholics (EOA). a subtype of alcoholic characterized by developing problem-drinking earlier, antisocial behaviors, high familial loading, and biological disease predisposition. Presumably, this medication combination counteracts the interaction between activated central 5-HT3 receptors and the endogenous opioid system during the mediation of alcohol-induced reward. We now hypothesize further that an important mechanism by which the combination diminishes alcohol consumption is through a reduction in craving. OBJECTIVE: To determine whether the combination of naltrexone and ondansetron is superior to a placebo at reducing craving among EOA, and the relationship between craving and drinking behavior in both treatment groups. METHODS: We conducted an 8-week double-blind placebo-controlled clinical trial in which 10 EOA were randomized to receive ondansetron (4 microg/kg b.i.d.) + naltrexone (25 mg b.i.d.) and 10 EOA had a placebo (total n=20) as an adjunct to weekly standardized group cognitive behavioral therapy. Craving was measured by using the obsessive compulsive drinking scale (OCDS). RESULTS: Craving ratings were scored on four subscales which where derived empirically by principal component structure analysis of the OCDS. EOA who received the medication combination, compared with the placebo, had significantly lower scores on "automaticity of drinking" and "alcohol consumption ". Reduction in automaticity of drinking was correlated with self-reported drinking for only the medication combination group. CONCLUSIONS: By reducing automaticity of drinking, the medication combination presumably decreased drinking salience and intensity. Larger scale studies testing these medications, both alone and together, among alcoholic subtypes are needed to establish and extend these promising findings.

Adult↗
PubMed2001

Treatment advances for cocaine-induced ischemic stroke: focus on dihydropyridine-class calcium channel antagonists.

OBJECTIVE: The authors reviewed the pathogenesis of cocaine-related cerebral ischemia, appraised current knowledge of its sequelae, and assessed the role of putative therapeutic agents, particularly dihydropyridine-class calcium channel antagonists. METHOD: The authors performed an OVID-based literature review of all indexed journals between 1966 and 2000. RESULTS: Cocaine abuse significantly increases the risk of ischemic stroke. The principal mechanism of cocaine-induced cerebral ischemia is vasospasm of large cranial arteries or within the cortical microvasculature. Increased levels of extracellular monoamines, particularly dopamine, mediate vasospasm. Neuroanatomical and labeling studies also have shown that dopamine-innervated neurons may regulate cerebral blood flow. Indeed, dopamine-rich brain regions appear to be relatively specific targets for cocaine-induced cerebral ischemia. Neuroimaging studies show that cocaine-induced hypoperfusion can persist even after 6 months of abstinence. Hypoperfusion can result in deficits on complex and simple psychomotor tasks but perhaps not on memory or attention. Severe cerebral ischemia can directly precipitate neuronal death and degradation, a condition exacerbated by liberation of the excitatory amino acid glutamate. Dihydropyridine-class calcium channel antagonists inhibit cocaine-mediated dopamine release on neurons involved in vasospasm and the control of cortical circulation. Other causes of cerebral ischemia include thrombogenesis and vasculitis. Although antithrombotic agents have potential in alleviating cocaine's neurotoxic effects, their use may be limited by the risk of spontaneous hemorrhage. CONCLUSIONS: Cocaine abuse can result in stroke, neuroischemia, and cognitive deficits that can persist even after prolonged abstinence. Dihydropyridine-class calcium channel antagonists, such as isradipine, show promise as therapeutic agents for preventing cocaine-induced cerebral ischemia.

Brain Ischemia↗
PubMed2001

Rapid clot formation and abnormal fibrin structure in a symptomatic patient taking fenfluramine--a case report.

A 35-year-old woman experienced symptomatic calf pain while taking a combination of fenfluramine and phentermine. All symptoms resolved when the medications were stopped, but pain returned when fenfluramine was restarted. Laboratory evaluation revealed mild elevations of aspartate aminotransferase and lactate dehydrogenase and a remarkably shortened prothrombin time (6.3 seconds). Additional studies revealed that the clots were composed of very thin fibrin fibers. All laboratory abnormalities, including the abnormal fibrin structure, completely resolved when fenfluramin was stopped. Direct addition of fenfluramine or phentermine to normal plasma did not alter either coagulation kinetics or fibrin structure, supporting the concept that the induced changes may have originated at the hepatic level. Clots composed of thin fibers are much more resistant to fibrinolysis, and could potentially put such patients at risk for thrombotic complications. This is the first report of clotting abnormalities associated with fenfluramine use. Subsequent to its use in this patient, fenfluramine was removed from clinical use due to reports of acquired valvular heart disease.

Adult↗
PubMed2001

Combining ondansetron and naltrexone treats biological alcoholics: corroboration of self-reported drinking by serum carbohydrate deficient transferrin, a biomarker.

BACKGROUND: Recently, we showed by using self-report that combining ondansetron (4 microg/kg twice a day) and naltrexone (25 mg twice a day) was effective at reducing drinking and increasing abstinence among early-onset alcoholics (EOAs), who are characterized by a range of antisocial behaviors and high biological and familial disease predisposition. Here, we investigated whether the self-reported differences in drinking would be corroborated by measurements of serum carbohydrate-deficient transferrin (CDT) level, a sensitive, reliable, and well-validated marker of transient alcohol consumption. METHOD: An 8-week double-blind clinical trial was performed in which 20 EOAs were randomized to receive ondansetron (4 microg/kg twice a day) and naltrexone (25 mg twice a day) or placebo as an adjunct to weekly standardized cognitive behavioral therapy. Serum CDT was assessed at weeks 0 (baseline), 4, and 8. RESULTS: Log serum CDT was significantly lower in the ondansetron and naltrexone group (group mean, 1.44 +/- 0.076) compared with the placebo group (group mean, 1.82 +/- 0.113), as evidenced by a main effect of group [F(1,15) = 7.2, p = 0.017; effect size = 0.32], visit [F(1,16) = 11.2, p = 0.004; effect size = 0.41], and an interaction between group and visit [F(1,16) = 27.54, p < 0.001; effect size = 0.63]. CONCLUSIONS: The combination of ondansetron plus naltrexone was superior to placebo at reducing serum CDT. This corroborated our self-reported drinking data and demonstrated that the medication combination is an effective treatment for EOAs.

Adult↗
PubMed2001

Use of the lapidus bunionectomy in first ray insufficiency.

Surgical management of first ray insufficiency in HAV or hallux limitus is crucial to long-term success. Although technically demanding, the Lapidus fusion serves to address the deformity at its apex and restores normal weight bearing to the foot. This arthrodesis offers predictable, durable results in addressing various first ray deformities and occupies an important place in the foot and ankle surgeon's armamentarium. The authors' technique is described herein for the interest of and evaluation by surgeons performing this procedure. As clinicians recognize the importance of addressing proximal components of the HAV deformity, the Lapidus and other procedures will likely see increased use in the surgical management of first ray deformities.

Arthrodesis↗
PubMed2000

Odorant molecular length: one aspect of the olfactory code.

Organic acid odorants of differing carbon number produce systematically different spatial patterns of [(14)C]2-deoxyglucose uptake in the glomerular layer of the olfactory bulb. Because increasing carbon number correlates with progressive increases in several molecular features, including hydrophobicity, length, and volume, we determined which of these properties was most associated with systematic changes in the location of an anterior, dorsomedial module responding to fatty acids. We exposed groups of rats to two series of organic acids that each had the same number of carbons, but differed in their hydrocarbon structures. These straight-chained, branched, cyclic, and double-bonded molecules differed independently in hydrophobicity, length, and volume. The only molecular property that was strongly correlated with the location of the module was molecular length, suggesting that this molecular feature is the principal determinant of the chemotopic organization of glomeruli within the module. We also found that distinct hydrocarbon structures produced large differences in spatial patterns of 2-deoxyglucose uptake in posterior parts of the bulb. Even subtly distinct structural isomers evoked posterior responses that differed greatly. The odorant 2-methylbutyric acid evoked much greater uptake in the posterior bulb than did its structural isomer 3-methylbutyric acid (isovaleric acid). These data suggest that posterior portions of the bulb may encode specific steric features of odorant molecules and that some odorant features may have an inherent or acquired greater representation than do others.

Animals↗
PubMed2000

Use of systemic agents in the treatment of acne vulgaris.

Effective treatment of acne vulgaris can prevent emotional and physical scarring. Therapy varies according to the severity of the disease. Topical medication is generally adequate in clearing comedonal acne, while inflammatory acne usually requires the addition of oral medication. Systemic antibiotics are used most frequently and can be highly effective. Newer formulations of combined oral contraceptives are also helpful in modulating sebum production in the female patient. Severe nodulocystic acne that does not respond to topical retinoids and systemic antibiotics may be treated with isotretinoin. However, the side effect profile of this medication is extensive, and physicians should be well-versed in its potential adverse effects.

Acne Vulgaris↗
PubMed2000

Modular representations of odorants in the glomerular layer of the rat olfactory bulb and the effects of stimulus concentration.

To study the mechanism whereby odorants are encoded in the nervous system, we studied the glomerular-layer activity patterns in the rat olfactory bulb evoked by closely related odorants from different chemical families. These odorants had a common straight-chain hydrocarbon structure, but differed systematically in their functional groups. Neural activity was mapped across the entire glomerular layer by using the ¿(14)C2-deoxyglucose method. Group responses were averaged and compared by using data matrices. The glomerular activity patterns that resulted from this analysis were comprised of modules. Unique combinations of modules were activated by each odorant, demonstrating what may be part of the neural code for odorants. Most of the modules were clustered together in the bulb, perhaps providing for enhanced contrast between related chemicals by means of lateral inhibition. We also determined whether changes in odorant concentration would affect spatial patterns of glomerular activity. Two odorants, pentanal and 2-hexanone, evoked different patterns at increased concentrations, with additional glomeruli being recruited at a great distance from glomeruli in which activity was evoked at lower concentrations. Humans report that both of these odorants change in perceived odor with increasing concentration. Three other odorants (pentanoic acid, methyl pentanoate, and pentanol) did not recruit new areas of glomerular activation with increasing concentration, and humans do not report a changed odor across concentrations of these odorants. The results suggest that changes in modular glomerular activity patterns could underlie altered odor perception across odorant concentrations, and they provide additional support for a combinatorial, spatially based code in the olfactory system.

Animals↗
PubMed2000

Treatment of seborrheic dermatitis.

Seborrheic dermatitis is a chronic inflammatory disorder affecting areas of the head and trunk where sebaceous glands are most prominent. Lipophilic yeasts of the Malassezia genus, as well as genetic, environmental and general health factors, contribute to this disorder. Scalp seborrhea varies from mild dandruff to dense, diffuse, adherent scale. Facial and trunk seborrhea is characterized by powdery or greasy scale in skin folds and along hair margins. Treatment options include application of selenium sulfide, pyrithione zinc or ketoconazole-containing shampoos, topical ketoconazole cream or terbinafine solution, topical sodium sulfacetamide and topical corticosteroids.

Dermatitis, Seborrheic↗