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Biomedical subjects

D Lockhart

Publications and source records attributed to D Lockhart.

14 recordsLinked to original sources
PubMed2003

Changes in CSF and plasma HIV-1 RNA and cognition after starting potent antiretroviral therapy.

The authors assessed CSF and plasma HIV-1 RNA and neuropsychological test performance (composite neuropsychological test Z score [NPZ-4]) in 25 HIV-1-infected subjects 4 and 8 weeks after beginning potent antiretroviral therapy that included a protease inhibitor. In the 14 subjects who entered the study on no antiretroviral treatment, NPZ-4 improvement was associated with decline in CSF HIV-1 RNA at both visits (p = 0.001 and p = 0.02), and those treated with zidovudine or indinavir had greater improvement in NPZ-4 at both visits compared to those treated with other drugs (p = 0.003 and p = 0.01).

Adult↗
PubMed2001

Justice, citizenship, and role definition effects.

A limitation of the organizational citizenship behavior (OCB) literature is that theory and empirical evidence suggest that some employees define OCBs as part of their job. A theoretical framework that addresses this problem is tested in this article. The framework focuses on 2 effects: a role enlargement effect (i.e., employees with more favorable attitudes define OCB as inrole behavior, which, in turn, results in greater citizenship) and a role discretion effect (i.e., the relationship between employees' attitudes and their citizenship will be stronger among employees who define OCB as extrarole behavior). In tests of this framework with 2 independent samples of supervisor-subordinate dyads, role definitions were found to moderate several relationships between procedural justice and OCB, providing support for the role discretion effect. Implications for OCB theory and research are discussed.

Adult↗
PubMed1999

Treatment of idiopathic pulmonary fibrosis with a new antifibrotic agent, pirfenidone: results of a prospective, open-label Phase II study.

Idiopathic pulmonary fibrosis (IPF) is a progressive clinical syndrome of unknown etiology and fatal outcome. Currently available therapies are ineffective and associated with significant adverse effects. Pirfenidone, a new, investigational antifibrotic agent, was evaluated for its tolerability and usefulness in terminally ill patients with advanced IPF. Consecutive patients with IPF and deterioration despite conventional therapy or who were unable to tolerate or unwilling to try conventional therapy were treated with oral pirfenidone. Treatment was administered on a compassionate basis (open-label). Fifty-four patients were followed for mortality, change in lung function, and adverse effects. Their mean age was 62, mean duration of symptoms 4.6 yr, and time since lung biopsy was 3.2 yr. Conventional therapy was discontinued in 38 of 46 patients; the other eight were able to decrease their prednisone dosage and eight had no previous conventional treatment. One- and 2-yr survival was 78% (95% CI 66%, 89%) and 63% (95% CI 50%, 76%), respectively. Patients whose lung functions had deteriorated prior to enrollment appeared to stabilize after beginning treatment. Adverse effects were relatively minor. The results of this study are encouraging. Pirfenidone is a promising new treatment for IPF that is well tolerated.

Administration, Oral↗
PubMed1999

The accuracy of the clinical diagnosis of new-onset idiopathic pulmonary fibrosis and other interstitial lung disease: A prospective study.

STUDY OBJECTIVES: Presently, surgical (open or thoracoscopic) lung biopsy (SLB) is the gold standard for the diagnosis of new-onset idiopathic pulmonary fibrosis (IPF) and other interstitial lung diseases (ILDs). The accuracy of a clinical diagnosis of IPF and other subsets of ILD has never been established in prospective studies. We investigated the accuracy and validity of a clinical diagnosis of IPF and ILD other than IPF. DESIGN: Prospective, independent evaluation of patients and clinical data by an ILD expert, of chest radiographic and high-resolution computed tomography (HRCT) features by a chest radiologist, and of histologic features of lung biopsy by a pulmonary pathologist in consecutive patients referred for a diagnostic evaluation of ILD. SETTING: Tertiary university medical center with recognized expertise in management of ILD. PATIENTS: Community patients referred for further definitive diagnostic evaluation of new-onset, untreated nonspecific ILD. INTERVENTION: By comparing the histologic features of SLB in 59 patients consecutively referred for further diagnostic evaluation of new-onset ILD with the clinical and radiologic diagnoses, we determined the sensitivity and specificity of clinical diagnosis and radiologic diagnosis (based on chest radiograph and HRCT features alone) of IPF and ILD other than IPF. A specific clinical diagnosis was independently made by the ILD expert after a thorough clinical assessment that included evaluation of an HRCT scan and bronchoscopic findings. The chest radiographs and HRCT scans were separately reviewed by the chest radiologist, who made a radiologic diagnosis independently. All patients underwent SLB within a month of preoperative "clinical" diagnosis. The clinician's and radiologist's diagnoses were then compared with the gold standard of histologic diagnosis. MEASUREMENTS AND RESULTS: Prior to the clinical evaluation at our center, 85% of patients who underwent SLB had nondiagnostic transbronchial biopsy. The diagnosis of IPF and ILD other than IPF was accurately made by clinical features alone in 62% of cases. The correct radiographic diagnosis of non-IPF ILD was made in 58% of the cases. The sensitivity and specificity of the clinical diagnosis of ILD other than IPF were 88.8% and 40%, respectively. The sensitivity and specificity of the radiographic diagnosis of ILD other than IPF were 59% and 40%, respectively. However, the sensitivity and specificity of the diagnosis of IPF on clinical grounds were 62% and 97%, respectively. The sensitivity and specificity of the radiologic diagnosis of IPF were 78.5% and 90%, respectively. CONCLUSIONS: In a center with recognized expertise in the management of ILD, the specificity of diagnosis of new-onset IPF based on a thorough clinical assessment or HRCT features alone is very high (97% and 90%, respectively), but the sensitivity is low (62% and 78.5%, respectively). Thus, not all patients with new-onset IPF require SLB for diagnosis, but a diagnosis of IPF will be missed in nearly one third of new-onset IPF cases despite evaluation by experts. The relatively low sensitivity and specificity of the diagnosis of ILD other than IPF also emphasizes that an SLB is indicated in patients with ILD in whom the diagnosis is unclear.

Adult↗
PubMed1999

The use of delayed computerized tomography in the evaluation of blunt abdominal trauma: a preliminary report.

This purpose of this study was to analyze the use of abdominal computed tomography (CT) imaging in patients with possible blunt abdominal trauma. A retrospective analysis of all trauma patients over a 1-year period (1993-1994) was conducted, with prospective study protocol in 52 patients using serial abdominal exam and hematocrits (Hcts) instead of abdominal CT for evaluation of blunt abdominal trauma. Urgent abdominal CT was used as the initial diagnostic test for evaluation of blunt abdominal trauma in 813 patients over this 1-year period. CT was obtained in 379 (46.6%) of these patients who arrived hemodynamically stable (admission systolic blood pressure > or = 90), had a Glasgow Coma Scale > 13, and had admission Hct > or = 35 because of distracting injuries, possible traumatic brain injury, or alcohol/drug use, which might render the abdominal physical exam unreliable. Only 47 CT scans (12.4%) were positive, and three patients (0.8%) required laparotomy. In an effort to more efficiently use abdominal CT, we performed a prospective study in 52 patients with possible blunt abdominal trauma, admission systolic blood pressure > or = 90, Hct > or = 35, Glasgow Coma Scale > 13, and a normal abdominal exam on admission. These patients were followed with serial abdominal examinations and Hcts every 6 hours for 24 hours, and delayed CT, when applicable. CT was obtained in seven patients (13.5%) for evaluation of fall in Hct or abnormal abdominal examination; all were negative for abdominal injury. A protocol using serial abdominal exams, Hcts, and delayed abdominal CT imaging may be useful in select patients to decrease the high number of negative routine abdominal CTs that are obtained in the evaluation of blunt abdominal trauma.

Abdominal Injuries↗
PubMed1986

Simultaneous determination of perhexiline and its monohydroxy metabolites in biological fluids by gas chromatography-electron-capture detection.

A rapid and sensitive method for the simultaneous determination of perhexiline and its cis-4-axial and trans-4-equatorial monohydroxy metabolites (M1 and M3, respectively) in human plasma, urine and bile is described. The assay utilises a single diethyl ether extraction, heptafluorobutyric acid anhydride derivatisation and separation and detection by gas chromatography-electron-capture detection. The limits of detection are 0.1 microgram/ml for perhexiline and 0.025 microgram/ml for the M1 and M3 metabolites. This method has been used in a five-day kinetic study of three healthy adult males who ingested a single 300-mg dose of perhexiline maleate. One of these volunteer subjects exhibited elevated plasma perhexiline and markedly reduced plasma and urinary M1 concentrations together with profoundly prolonged plasma and urinary M1 elimination times when compared with the other two subjects. These differences are thought to be of genetic origin. There were also obvious differences in urinary M3 concentrations which were discussed.

Adult↗
PubMed1985

The sex distribution of children in care.

It is shown that there is a substantial and sustained disparity, both on a national and on a regional basis, between the numbers of males and the numbers of females in care. The disparity is analysed by examining the reasons for entering care, and the legal status of those in care. It is shown that in the aggregate the disparity is caused by imbalances in admissions, particularly in certain key legal and administrative categories. The phenomenon is also shown to have both geographical and accommodation dimensions, and some conjectures for its behavioural origins are offered.

Adolescent↗
PubMed1985

Therapeutic monitoring of the anti-anginal drug perhexiline maleate.

Patients taking oral doses of perhexiline maleate have been examined. Measurement of serum perhexiline concentrations established that different dose requirements between patients were necessary due to the different doses at which drug saturation was achieved. Measurement of serum perhexiline concentrations are essential if side-effects from the drug are to be avoided.

Angina Pectoris↗
PubMed1981

Hepatocellular enzyme patterns and hepatitis B virus exposure in multitransfused young and very young hemophilia patients.

Thirty-eight children with severe hemophilia A, 11 years of age and under, were evaluated by initial and follow-up liver function tests (LFTs) in relation to age of onset of transfusion therapy. Each child had at least two complete evaluations within one year for a follow-up period of at least one year. The mean number of exposure days was 36 with a mean of 275 units of factor VIII per exposure day prior to initial LFTs. At initial testing, 30% of patients demonstrated antibody to HBsAg and 39--51% at least one abnormal serum enzyme level (AST, ALT, LDH). During an average follow-up period of 34.8 months, two children developed HBsAg-positive icteric hepatitis. Of those initially serologically negative for HBsAg or antibody, 44% became antibody-positive. Intermittent abnormalities of at least one serum enzyme were observed in 79% of the patient group, with 13% and 8% being persistently normal and abnormal. Eleven children born after January 1976, receiving only third-generation RIA-tested products for HBsAg, constituted a subgroup. Although only one child at first assessment had evidence of hepatitis B virus exposure, 55% had elevated ALTs, indicating considerable frequency of non-A, non-B hepatitis in this very young group.

Child↗