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Biomedical subjects

D L Herbert

Publications and source records attributed to D L Herbert.

At least 19 recordsLinked to original sources
PubMed1992

The effects of feedback on the behavior of depressed inpatients in two structured interactions.

This study examined the responsivity of depressives' behavior to contingent social feedback within the framework of Coyne's and Lewinsohn's models of depression. Subjects included 10 depressed inpatients, 8 nondepressed psychiatric inpatients, and 10 nondepressed individuals. Each subject participated in two structured interactions with an experimenter in baseline phases and phases in which ongoing contingent feedback was provided by a pair of observers. The results revealed that the behavior of all three subject groups was responsive to the feedback in both interactions. The results are consistent with past research demonstrating social skills problems among depressed individuals but do not support the notion of a social skill deficit in depression. The results are consistent with Coyne's model of depression and suggest that the problematic social behavior often associated with depression may be modifiable by immediate veridical feedback from others.

Adult↗
PubMed1989

Effectiveness of matched, mismatched, and package treatments of depression.

The three purposes of this study were: (a) to determine if treatment that is matched to a depressed subject's problematic behavioral response class (irrational cognitions, social skills problems, few pleasant events) is more effective in alleviating depression than is mismatched treatment; (b) to determine if a package treatment is as effective as or more effective than a matched treatment and more effective than a mismatched treatment in alleviating depression; and (c) to determine if a specific treatment produces more changes in its logically-related response class than in logically-unrelated response classes. Nine depressed women were assigned to one of three multiple baseline designs across subjects; subjects in each design received, respectively, matched, mismatched, or a package treatment. Results strengthened two hypotheses, that matched treatment and package treatment are both effective in alleviating depression. Specific treatments did not, however, differentially affect their logically-related response classes.

Adult↗
PubMed1985

Vascularization of tricalcium phosphate, an artificial bone substitute: preliminary observations.

Tricalcium phosphate (TCP), a biodegradable artificial bone substitute, was used to study the following questions: i) can TCP be vascularized; ii) do ectopically placed implants have osteoinductive capacity; and iii) does vascularization affect implant resorption? Implants were placed in dogs in several areas: i) subcutaneous controls; ii) wrapped with latissimus dorsi muscle; iii) wrapped in omentum; iv) saphenous and thoracodorsal av pedicles threaded through implant. Prior to harvest, animals were given tetracycline and implants were harvested at 3, 6, and 9 weeks. Microfil was injected prior to sacrifice and specimens were xeroradiographed. Histology and computerized axial tomography were obtained. From this study, we conclude that 1) TCP can be vascularized; 2) the most effective method of vascularization was by an AV pedicle threaded through the implant; 3) vascularized implants did not have osteoinductive properties per se, and 4) in the time observed no difference in implant resorption was demonstrated between the test groups.

Animals↗
PubMed1985

Three-dimensional computed tomography of acetabular fractures.

Computer programs that produce 3D surface reformations from sets of contiguous axial CT scans were used in evaluating a variety of acetabular fractures in 20 patients. The 3D images were easily correlated with plain radiographs, and new views were produced that provided a unique perspective not obtainable by conventional radiography. The 3D images were useful in complex displaced fractures in cases in which the interpretation of plain radiographs was difficult. Plain radiographs and conventional CT scans were more sensitive than the 3D images in detecting undisplaced fractures.

Acetabulum↗
PubMed1984

Xenon/CT blood flow mapping of the kidney and liver.

A noninvasive technique for measuring blood flow by xenon-enhanced X-ray transmission CT has been developed and reported quite extensively in recent years. In this method nonradioactive xenon gas is inhaled, and the temporal changes in radiographic enhancement produced by the inhalation are measured by sequential CT. Time-dependent xenon concentration within various tissue segments is used to derive local blood flow maps. The method has been amply discussed in relation to assessment of local cerebral blood flow. Its application to other body organs is explored in this paper, in which results from six preliminary blood flow studies in the liver and kidneys of nonhuman primates are reported. Blood flow in renal cortex ranged from 150 to 280 ml/100 cc/min and hepatic tissue perfusion from 80 to 120 ml/100 cc/min. The advantages and limitations of the method in such applications are discussed.

Animals↗
PubMed1983

Pulmonary function in progressive systemic sclerosis. Comparison of CREST syndrome variant with diffuse scleroderma.

The pulmonary function and chest roentgenograms were evaluated in 88 patients with the CREST syndrome variant of progressive systemic sclerosis (PSS or scleroderma). Seventy-two percent of the patients had abnormal pulmonary function. An isolated decrease in diffusing capacity was the most common abnormality noted, followed by restrictive abnormalities and airway obstruction. Chest roentgenograms revealed interstitial infiltrates consistent with pulmonary fibrosis in 33 percent. When compared to a contemporaneous group of 77 patients with PSS and diffuse scleroderma, patients with the CREST syndrome had similar abnormalities on pulmonary function testing and chest roentgenogram. However, patients with the CREST syndrome had a lower mean diffusing capacity despite a higher mean vital capacity; this combination of findings suggests primary pulmonary vascular disease. Calcified granulomata were identified significantly more often in PSS-CREST patients, while superior rib notching occurred exclusively in patients with PSS and diffuse scleroderma. The CREST variant of PSS is associated with frequent roentgenographic and pulmonary function abnormalities similar to those seen in PSS with diffuse scleroderma.

Adult↗
PubMed1982

Bromocriptine treatment of women with suspected pituitary prolactin-secreting microadenomas.

The present study was designed to investigate the efficacy of bromocriptine in reducing serum prolactin (PRL) levels and in decreasing the size of PRL-secreting microadenomas. Bromocriptine, 5.0 mg, was administered daily for 2 years of 17 women who had galactorrhea, hyperprolactinemia, and hypocycloidal polytomographic evidence suggestive of a pituitary microadenoma. Serum PRL levels were normalized in 16 of 17 women during therapy. Associated with this was resumption of regular menses in 15 of 16 women with menstrual dysfunction and cessation of galactorrhea in 16 of the 17 women. Improvement in the roentgenographic appearance of the sella turcica occurred in two women. No progression in tumor size was found during the course of therapy. Side effects attributed to bromocriptine were minimal, transient, and usually well tolerated. These data suggest that bromocriptine is an appropriate therapeutic modality for PRL-secreting pituitary microadenomas.

Adenoma↗
PubMed1982

Errors associated with single-scan determinations of regional cerebral blood flow by xenon enhanced CT.

Possible errors in the determination of xenon concentrations in arterial blood, and uncertainties in CT tissue enhancements during inhalation of xenon-oxygen mixtures, are used to assess errors in the determination of regional cerebral blood flow by the in vivo autoradiographic (single-scan) technique. The results of this study indicate that errors associated with the determination of xenon concentrations in arterial blood decrease rapidly as the time of scanning after the initiation of xenon inhalation is increased. Analysis of errors caused by statistical uncertainties in image enhancement indicate that time of scanning is optimal between 1.5 and 2.5 min for determination of fast flow, while errors in slow-flow determinations gradually decrease as the time of scanning increases.

Autoradiography↗
PubMed1982

Mapping of human local pulmonary ventilation by xenon enhanced computed tomography.

Functional maps of local pulmonary ventilation are derived from serial computed tomographic images acquired prior to and during a short period of inhalation of subanesthetic xenon/oxygen gas mixtures. Preliminary results from human studies yield quantitative maps of local ventilation rates with excellent anatomic specificity demonstrating nonuniformities in the distribution of ventilation in normal and abnormal human lungs.

Adult↗
PubMed1982

Spiculation of antral margin in erosive gastritis.

Because of the low yield, conventional barium studies had been considered an unreliable methods of detecting erosions of the stomach. With the advent of the double contrast examination, the literature is now replete with examples of erosive demonstrated by this technique. As in endoscopy, the erosions are visualized "en face" only. No case, however, has been recorded in which the diagnosis was made on a profile view of the erosions. We present such a case of erosive gastritis with two unusual features in which 1) the diagnosis was made on a conventional single contrast study and 2) the lesions were identified in profile.

Adult↗
PubMed1981

Regional pulmonary ventilation measurements by xenon enhanced dynamic computed tomography: an update.

New developments in computed tomographic technology permit rapid, serial images that may yield information concerning tracer kinetics through a large tissue volume. One possible application of these developments is the derivation of local lung ventilation by observing the temporal changes of stable xenon concentrations. Preliminary results from six multilevel ventilation studies in dogs demonstrate that the lung may be repeatedly imaged during reproducible phases of respiration even when interscan table incrementation is employed to survey a number of tissue segments and breathing is permitted between scans. In addition, subanesthetic xenon concentrations provide adequate enhancement for possible quantification.

Animals↗
PubMed1981

Quantitative bone assessments: applications and expectations.

Although, with the newer and more sophisticated radiologic methods the precision of bone mass measurement has been greatly improved, it is still impossible to predict the imminence of osteoporotic fractures, for two main reasons. First, current radiologic methods measure bone mass accurately only in appendiceal bone (largely cortical and regularly shaped) and not in axial bone (largely trabecular and irregularly shaped). However, most clinically significant fractures occur in the axial skeleton and involve trabecular bone, which is more prone than cortical bone to resorptive losses. Second, because of large differences in body habitus, the normal range of bone densities varies widely in any cohort of the same sex and race. Thus, although bone density measurements cannot be used to predict osteoporotic fractures, they have an important application in monitoring changes in skeletal mass for therapeutic and prophylactic purposes.

Adult↗
PubMed1981

The wandering broncholith.

In a patient with "stone asthma" the obstructing broncholith moved from one lung to the other and was later spontaneously expectorated.

Bronchial Diseases↗
PubMed1979

The significance of concordance in mammographic interpretations.

Twenty-eight women participating in a screening program had a breast cancer diagnosed subsequent to the report of a negative mammogram which was read by only one of a group of radiologists. Fourteen occurred prior to a scheduled routine screening visit (interval cancers) and 14 were detected during such an examination. The negative mammograms from the 28 cancer patients, together with those from 120 women without cancer (controls) were independently reviewed by each member of a panel of three radiologists. Forty-six percent of the cancer cases and 5.8% of the controls were interpreted as positive by two or more of the radiologists. These findings suggest that agreement among several independent reviewers enchances the value and accuracy of mamography by reducing the number of false negative interpretations.

Breast Neoplasms↗
PubMed1979

Normal sellar variations in frontal tomograms.

Frontal tomograms of 100 normal sellae were examined. The sellar floor was usually flat or had a smooth central depression of less than 2 mm. Six per cent had a marked central depression. In such cases, the lateral angles of the sellar floor, usually rounded, may be sharp, so that the diagnosis of intrasellar lesions cannot be based on such alterations. Where one or more septa divided the sphenoid sinus asymmetrically, sellar floor configuration was modified in 21% of cases. The normal sellar floor may have a slope of up to 8 degrees, making analysis of subtle contour variations difficult.

Adenoma↗
PubMed1979

Bone stress: a radionuclide imaging perspective.

Thirty-five college athletes with lower leg pain underwent radiography and radionuclide studies to rule out a stress fracture. Their asymptomatic extremities and 13 pain-free athletes served as controls. Four main patterns were observed: (a) sharply marginated scintigraphic abnormalities and positive radiographs; (b) sharply marginated scintigraphic abnormalities and negative radiographs; (c) ill-defined scintigraphic abnormalities and negative radiographs; and (d) negative radionuclide images and negative radiographs. Since the patients with the first two patterns were otherwise identical medically, the authors feel that this scintigraphic appearance is characteristic of bone stress in the appropriate clinical setting, regardless of the radiographic findings. A schema is proposed to explain the occurrence of positive radionuclide images and negative radiographs in the same patient, using a broad conceptual approach to the problem of bone stress.

Adolescent↗