Biomedical subjects

R Gibbons

Publications and source records attributed to R Gibbons.

60 records · Page 4Linked to original sources

PubMedDate not supplied

Clinical diagnosis of substance use disorders in private psychiatric populations.

The clinical diagnoses of comorbid substance use and psychiatric disorders by psychiatrists in a private psychiatric inpatient setting were analyzed. Two hundred patients consecutively discharged from a private university-affiliated psychiatric service by clinical psychiatrists were examined for concomitant substance use and psychiatric disorders according to DSM-III-R criteria for Axis I and Axis II disorders. Fifty-nine patients (30%) were diagnosed with a comorbid substance use and psychiatric disorder on Axis I, supporting findings of previous studies. Comorbid diagnosis patients were more likely to be male (54%, 32) than were psychiatric only (noncomorbid diagnosis) patients (males 37%, 51). There were no differences between comorbid (dual diagnosis) and noncomorbid diagnoses in age, mean length of stay, or discharge type. Of the 59 patients with comorbid disorders, 83% had Axis I diagnoses, and 64% had Axis II diagnoses. Polysubstance use disorder was the most common dual diagnosis, cooccurring with an Axis I diagnosis in 47% of patients with an Axis II diagnosis in 45%. Psychiatrists in clinical psychiatric inpatient settings diagnose substance use disorders in rates similar to public settings despite absence of specific addiction treatment.

Adult↗

PubMedDate not supplied

Age-related bone loss in mice is associated with an increased osteoclast progenitor pool.

Age-associated osteopenia has been documented to occur in mice and, therefore, provides a model system whereby mechanisms of bone loss can be assessed in vivo and in vitro. One such mechanism, that could explain the increased resorptive activity seen in some forms of osteopenia, is an age-associated increase in the osteoclast precursor pool and osteoclastogenic formation. To test this hypothesis, we studied the bone marrow composition of aged (24 months) mice to determine if increased numbers of monocyte/macrophage/osteoclast precursor cells (MMOPC) were present when compared to young (4-6 months) animals. Our data show a moderate increase of 20-30% more hematopoietic cells obtained from the long bones of the aged animals. However, both liquid and semi-solid culture techniques demonstrate an approximately 2-3.5-fold increase in the numbers of plastic adherent macrophages or mononuclear colonies in bone marrow derived from the aged mice when stimulated by interleukin-3 (IL-3), granulocyte-macrophage colony stimulating factor (GM-CSF) or macrophage colony stimulating factor (GM-CSF), indicating a preferential increase in MMOPCs. In addition, cells derived from the aged mice show higher levels of cytokine stimulated incorporation of [3H]-thymidine and [3H]-leucine, with increased protein synthesis seen up to 7 days after cytokine stimulation, suggesting that these cells also have an enhanced sensitivity to cytokines.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMedDate not supplied

Variability of Doppler echocardiographic indexes of left ventricular filling in transplant recipients and in normal subjects.

This study examines the reproducibility and variability of pulsed wave Doppler versus continuous wave Doppler ultrasound indexes of left ventricular filling in cardiac allograft recipients and in normal subjects. The following indexes were studied: isovolumic relaxation time, pressure half-time, peak early mitral flow velocity, and peak mitral flow velocity after atrial systole. Intraobserver and interobserver variability were assessed by regression analysis. Individual components of variance (subject, reader, beat, day, and tracing) were estimated in a subset of five patients and five normal subjects, and estimated total variance defined for each group. Temporal (day-to-day) variability for 95% confidence was estimated for these patients and for normal subjects. Temporal variability in the group from which the subsets were drawn was measured from absolute and percent change in values on two occasions. Estimated and observed 95% confidence limits were compared. Intersubject variability was the largest component of variance in both transplant recipients and in normal subjects. For all indexes in transplant recipients (in the absence of rejection) and normal subjects, observed absolute mean differences (+/- 2 standard deviations) between values from recordings taken on two different days were larger than the 95% confidence limits estimated from the components of variance analysis. The observed 95% limits for transplant recipients versus normal subjects were as follows: isovolumic relaxation time, 20 msec versus 6 msec; pressure half-time, 16 msec versus 9 msec; peak early mitral flow velocity, 32 cm per second versus 17 cm per second; and peak mitral flow velocity after atrial systole, 28 cm per second versus 10 cm per second.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Echocardiographic contrast increases the yield for right ventricular pressure measurement by Doppler echocardiography.

Doppler ultrasound has become accepted as a measurement of right ventricular systolic pressure in patients who have a quantifiable signal from tricuspid regurgitation. This study evaluated the use of intravenous injection of saline solution for echo contrast to increase the percentage of quantifiable tricuspid regurgitant signals in patients who have any detectable tricuspid regurgitation at baseline. Patients underwent a standard Doppler evaluation, followed by a contrast study with the injection of 4 to 6 ml of agitated saline solution into a brachial vein. Baseline and contrast tricuspid regurgitant signals were assessed for quality, quantifiability, and reproducibility of the derived pressures by three observers on two occasions. The average absolute pairwise deviation among the three observers was low: 1.6 mm Hg (standard deviation, 1.4 mm Hg). The intraobserver mean discrepancy was low: 0.03 mm Hg (standard deviation, 2.33 mm Hg). Patients who did not have tricuspid regurgitation (n = 10) failed to develop such regurgitation during contrast injection. Only eight of 40 patients (20%) who had trace or mild tricuspid regurgitation had quantifiable baseline signals, but 34 patients (85%) had quantifiable signals with contrast injection. All patients who had mild to moderate, moderate, or severe tricuspid regurgitation (n = 10) had quantifiable signals before contrast injection. Of all patients who had any tricuspid regurgitation, 88% had quantifiable signals with contrast injection. Echo contrast was shown to improve the yield of quantifiable signals in patients who had trace and mild tricuspid.

Adult↗

PubMedDate not supplied

Nuclear cardiology in hospital-based practice.

Managed care has drastically changed the environment in which we practice hospital-based nuclear cardiology. As of 1995, traditional fee for service comprises only 8% of all reimbursement in the United States. Nuclear cardiology is now a cost center, not a revenue center, for the hospital. In Minnesota, many physicians and hospitals work together toward common goals in various "integrated health service networks." There are several ways in which nuclear cardiology can help a health care network reduce costs. Results of myocardial perfusion, for example, can be used to help reduce unnecessary coronary angiography and revascularization procedures. On the other hand, nuclear cardiology is generally not cost-effective in patients with a low likelihood of benefitting from the test and should usually be avoided in such patients.

Cardiology↗

PubMedDate not supplied

Sensitivity and specificity of diastolic indexes for rejection surveillance: temporal correlation with endomyocardial biopsy.

Although acute diastolic dysfunction is an early sequela of the rejecting heart, reported sensitivities and specificities have varied widely when Doppler echocardiography is used for rejection surveillance. This study examines the temporal relationship between changes in Doppler echocardiographic indexes of diastolic function and sequential endomyocardial biopsies to identify possible factors accounting for false-positive and false-negative results. A total of 114 Doppler echocardiographic studies and biopsies were performed weekly in 39 patients aged 14 to 59 years during the initial 3 months after heart transplantation. All Doppler examinations were within 24 hours of biopsy and were analyzed in a blinded fashion. Onset of restrictive physiology, defined as a 15% decrease in either isovolumic relaxation time or pressure half-time, was determined by analysis of the Doppler mitral flow velocity curve.

Adolescent↗