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Biomedical subjects

B Steinberg

Publications and source records attributed to B Steinberg.

At least 19 recordsLinked to original sources
PubMed2001

Cranial nerve clock. Part 1. A declarative memory paradigm.

RATIONALE AND OBJECTIVES: The authors performed this study to compare a declarative memory paradigm developed to help teach medical students about the cranial nerves with a traditional text-based approach. MATERIALS AND METHODS: The authors designed a clock-based paradigm to help medical students learn about the cranial nerves. To enhance memorization and related brain activation, the paradigm uses visual, spatial, and word associations in the context of an analog clock face. Twenty-one undergraduate students were randomly divided into two groups. Group T viewed traditional text slides, and group C viewed text slides followed by the corresponding cranial clock slides. Subjects were tested before and after these sessions. RESULTS: Group C performed significantly better than group T in learning the names of the cranial nerves and their correct order (P < .011). Recall of name, number, and function was better for 11 of 12 cranial nerves, with statistical significance reached for nerves III (P = .005), V (P = .04), and X (P = .03). CONCLUSION: Alternative teaching strategies may help improve declarative memory.

Cranial Nerves↗
PubMed1999

Chimpanzee thumb muscle cross sections, moment arms and potential torques, and comparisons with humans.

This study investigates the morphological basis of differences between humans and chimpanzees in the kinematical and dynamical parameters of the musculature of the thumb. It is partly intended to test an hypothesis that human thumb muscles can exert significantly greater torques, due to larger muscle cross-sectional areas or to longer tendon moment arms or to both. We focus on the estimation of the potentials of thumb muscles to exert torques about joint axes in a sample of eight chimpanzee cadaver hands. The potential torque of a muscle is estimated by taking the product of a muscle's physiological cross-sectional area (an estimator of force) with its dynamical moment arm (derived from the slope of tendon excursion versus joint angular displacement, obtained during passive movements of cadaver thumb joints). Comparison of our results with similar data obtained for humans at the same Mayo Clinic laboratory shows significant differences between humans and chimpanzees in potential torque of most thumb muscles, those of humans generally exhibiting larger values. The primary reason for the larger torques in humans is that their average moment arms are significantly longer, permitting greater torque for a given muscle size. An additional finding is that chimpanzees and humans differ in the direction of secondary thumb metacarpal movements elicited by contraction of some muscles, as shown by differences in moment arm signs for a given movement in the same muscle. The differences appear to be related to differences in the musculo-skeletal structures of the trapeziometacarpal joint.

Animals↗
PubMed1999

Effect of human bone morphogenetic protein 2 implant on tooth eruption in an experimental design.

This study evaluated the influence of recombinant human bone morphogenetic protein 2 (rhBMP-2) on the development and eruption of the secondary dentition. Primary premolar tooth extraction sockets in 12 16-week-old felines were implanted with either rhBMP-2, in collagen sponge or with buffer/absorbable collagen sponge (ACS). Unoperated jaw quadrants served as controls. Experimental conditions were randomized between jaw quadrants in all animals. Two animals receiving rhBMP-2/ACS and buffer/ACS in two quadrants per implant were sacrificed at 4 weeks postsurgery. Ten animals receiving rhBMP-2/ACS (two quadrants), buffer/ACS implants (one quadrant), and one quadrant serving as an unoperated control were evaluated at 12 weeks postsurgery. Clinical assessments included healing, eruption patterns, and crown development. Radiographic assessments included tooth development, eruption patterns, and bone formation. Histological observations were also made from the 4-week animals. The secondary dentition remained unerupted at 4 weeks postsurgery. Histological analysis showed normal alveolar bone coronal to the erupting teeth in rhBMP-2/ACS-implanted quadrants. At 12 weeks postsurgery, all teeth were erupted without differences between quadrants. Clinically, the crowns of all teeth were normal. Radiographs suggested that teeth in rhBMP-2/ACS- and buffer/ACS-implanted jaw quadrants exhibited similar tooth development and eruption patterns as the normal control. The evidence from this study suggests that surgical implantation of rh-BMP-2/ACS in the pathway of the developing and erupting secondary dentition does not interfere with the normal development and eruption patterns of the teeth.

Absorbable Implants↗
PubMed1999

State of the art in oral and maxillofacial surgery: treatment of maxillary hypoplasia and anterior palatal and alveolar clefts.

As the new millennium approaches, it seems appropriate to look back at where we have been and where we are going with the care of patients with facial deformities. None of us can deny that although changes have been made, many current treatment modalities are no more than modifications of old techniques. We are, however, poised to make dramatic improvements in the management of facial abnormalities as we enter the new century and millennium. Biotechnology, genetic manipulation, and new surgical technology will become pervasive, and perhaps we will move from "modification" of the old into a completely new era of therapeutic approaches to the care of dentofacial deformities. "Opportunities multiply as they are seized" (from Sun Tzu), and the time of opportunity is approaching. This review will attempt to look at the state of the art in cleft care and in oral and maxillofacial surgery: where we have been and where we are going. It will be clear that there is overlap between specialties and that these overlaps will become greater as new regimens in the care of facial deformities come to the forefront.

Alveolar Process↗
PubMed1998

EMG study of hand muscle recruitment during hard hammer percussion manufacture of Oldowan tools.

The activity of 17 hand muscles was monitored by electromyography (EMG) in three subjects during hard hammer percussion manufacture of Oldowan tools. Two of the subjects were archaeologists experienced in the replication of prehistoric stone tools. Simultaneous videotapes recorded grips associated with the muscle activities. The purpose of the study was to identify the muscles most likely to have been strongly and repeatedly recruited by early hominids during stone tool-making. This information is fundamental to the identification of skeletal features that may reliably predict tool-making capabilities in early hominids. The muscles most frequently recruited at high force levels for strong precision pinch grips required to control the hammerstone and core are the intrinsic muscles of the fifth finger and the thumb/index finger regions. A productive search for skeletal evidence of habitual Oldowan tool-making behavior will therefore be in the regions of the hand stressed by these intrinsic muscles and in the joint configurations affecting the relative lengths of their moment arms.

Animals↗
PubMed1998

The striatum in a putative cerebral network activated by verbal awareness in normals and in ADHD children.

The aim of the present study was to evaluate the striatum's involvement in verbal awareness (semantic processing and supra-modal attention) in normals and children with attention deficit hyperactivity disorder (ADHD). Our previous finding of striatal hypoperfusion in ADHD at rest, supports our prediction that the striatum will also show reduced activation in response to tasks requiring verbal awareness. Regional cerebral blood flow (rCBF) was studied with the Xenon133 SPECT method in 12 boys with ADHD and six normal controls. The experimental controls included: (1) White Noise, (2) Passive Listening to a series of animal names, and (3) Detection of Targets ("dangerous animals") from the same series of animal names. The conditions were selected to isolate the semantic processing (Passive Listening - White Noise) and supra-modal attention components (Detection of Targets - Passive Listening of verbal awareness). ADHD children had decreased rCBF in the right striatum when compared to normals (mean difference from grand mean of each subject 8.06 ml/100 g/min vs 14.16 ml/100 g/min, p < 0.05). Factor analysis of the rCBF data revealed high factor I loadings for the frontal and striatal regions, which, in conjunction with the nature of the experimental conditions supported the inference that factor I mediated verbal awareness. Factor scores, which summarized the activity of all of the regions of interest (ROI's) on factor I, were differentially affected by the language component of the experimental tasks. Function scores were derived from factor I for the anterior cingulum and infero-frontal regions to evaluate their respective involvement in supra-modal attention and semantic processing. Function scores were also developed for the striatum, because of its central location and potential role in ADHD. The anterior cingulum was activated by supra-modal attention. The infero-frontal and the striatal regions were both activated by the language demands of the tasks. However, the striatum demonstrated reduced function scores (p < 0.05) in ADHD for all tasks. Our finding that the anterior gyrus cinguli were activated by supramodal attention and that the infero-frontal and striatal regions were activated by semantic processing supports the involvement of these ROI's in verbal awareness. Furthermore, the depressed functional contribution of the striatum to verbal awareness in ADHD children is consistent with and helps to explain their reduced cognitive control over behaviour and mental function.

Journal Article↗
PubMed1997

The comorbidity of anxiety and depression.

OBJECTIVE: This study explored the effect of comorbid anxiety disorders in patients admitted to an inpatient specialist Mood Disorders Unit for the treatment of a primary major depressive episode. METHOD: Subjects were assessed on admission and discharge. DSM-III-R diagnoses for major depression and anxiety disorders were established using CIDI-Auto; comorbid anxiety disorders were coexistent in time with the major depression, with both conditions meeting diagnostic criteria at the time of assessment. Severity of illness was assessed using the Hamilton Depression/Melancholia Scale, the revised Hamilton Anxiety Scale and the revised Beck Depression Inventory. RESULTS: For the analysis, the study cohort was divided into three groups: depression alone (n = 33), one comorbid anxiety disorder (n = 15), and two or more comorbid anxiety disorders (n = 24). No particular anxiety disorder predominated. Interestingly, the presence or absence of comorbid anxiety with severe major depression made no significant difference to treatment choice or outcome results. Specifically, there was no significant difference between the three groups in the utilisation of electroconvulsive therapy and pharmacotherapy (including antidepressants, benzodiazepines and neuroleptics); all subjects improved significantly on both depression and anxiety ratings, and length of inpatient stay did not vary significantly between the three groups. CONCLUSIONS: The existence of comorbid anxiety disorders in those patients who presented for treatment of a primary major depressive episode did not significantly effect choice of treatment or treatment outcome, suggesting that there is a close interrelationship between the two conditions.

Adult↗
PubMed1996

Incidence of maxillofacial involvement in arthrogryposis multiplex congenita.

PURPOSE: This study determined the incidence of maxillofacial involvement in patients diagnosed with arthrogryposis multiplex congenita (AMC). PATIENTS AND METHODS: Twenty-three patients were evaluated by the pediatric physical medicine and rehabilitation, orthopedic surgery, and pediatric oral and maxillofacial surgery departments. Any patient in whom the diagnosis of AMC was in doubt was excluded from the study. All patients with limited mandibular function underwent computed tomography (CT) examination of their temporomandibular joints (TMJ). The results of physical therapy were followed. RESULTS: Five of the 23 patients diagnosed with AMC were found to have maxillofacial involvement, eg, presence of cleft palate, Robin-like sequence, high-arched palate, open-bite deformity, facial muscle weakness, esophageal dysfunction, and limited mandibular opening. No TMJ abnormalities were found by CT scan. Physical therapy was used for treatment of the limited opening, but relapse occurred quicky after therapy was discontinued. CONCLUSION: The incidence of maxillofacial findings is similar to that of most other reports. Treatment involves surgical correction of abnormal anatomy when possible (ie, cleft repair), symptomatic management (ie, esophageal dysfunction), and physical therapy.

Adolescent↗
PubMed1996

Management of contaminated bone grafts: an experimental in vitro study.

OBJECTIVES: This study tested various protocols for bone decontamination after bacterial contact to determine if these treatments altered bone structure. STUDY DESIGN: Femurs from five Sprague-Dawley rats were sectioned and separated into eight groups. These were contaminated in a broth containing Pseudomonas aeroginosa and Staphylococcus aureus. Subsequently, the groups were treated with eight different decontamination regimens. A Scheffe's Grouping test was used to statistically compare the bacterial counts after each treatment protocol. RESULTS: Treatment with 4% chlorhexidine gluconate and 4% alcohol, Neosporin, cefazolin, and saline solution had little effect on bacterial growth. However, povidone-iodine, autoclaving, and ethyl alcohol with ethanol did significantly decrease the bacterial colony counts from the bone specimens. The autoclave and ethyl alcohol/ethanol induced changes in bony histologic examination. CONCLUSIONS: Results suggested that povidone-iodine decontaminates bone specimens without altering histologic conditions. Determination of successful grafting of bone treated with this protocol is required before its recommendation for clinical use.

Animals↗
PubMed1995

The cranial base in obstructive sleep apnea.

PURPOSE: The purpose of this investigation was to determine if there are cranial base differences in adults with obstructive sleep apnea (without identifiable craniofacial abnormalities) when compared with those of adults without airway problems. METHODS: Cephalometric analysis of the cranial base of 52 patients with documented sleep apnea were compared with 96 normal adult patients. Each of the groups was subdivided based on skeletal profiles (Class I, II, III). Cephalometric measurements included cranial base flexure angle and anterior and posterior cranial base lengths. Standard analysis of variance and Students' t test were used to determine level of significance. RESULTS: The cranial base flexure angle in patients with documented sleep apnea was significantly more acute than that found in the nonapnea group. Patients with a skeletal Class III profile had the most acute cranial base flexure whereas those with Class II profiles had the most obtuse angles. This pattern was true for apnea and nonapnea groups. No cranial base length differences could be found in either group. CONCLUSION: The results of this study demonstrate that there were abnormalities of the cranial base in patients with obstructive sleep apnea. Abnormalities of the cranial base seen in "nonsyndrome" obstructive sleep apnea patients are similar to those seen in patients with certain identifiable syndromes. This may suggest that sleep apnea is a reflection of a form of craniofacial syndrome.

Adult↗
PubMed1995

Anterior leaflet procedures during mitral valve repair do not adversely influence long-term outcome.

OBJECTIVES: This study was done to assess the impact of anterior mitral leaflet reconstructive procedures on initial and long-term results of mitral valve repair. BACKGROUND: It has been suggested that involvement of the anterior leaflet in mitral valve disease adversely affects the long-term outcome of mitral valve repair. Our policy has been to aggressively repair such anterior leaflets with procedures that include triangular resections in some cases. METHODS: From June 1979 through June 1993, 558 consecutive Carpentier-type mitral valve repairs were performed. The anterior mitral leaflet and chordae tendineae were repaired in 156 patients (mean age 58 years). The procedures included anterior chordal shortening in 78 patients (50%), anterior leaflet resections in 44 (28%), resuspension of the anterior leaflet to secondary chordae in 42 (27%) and anterior chordal transposition in 27 (17%). Concomitant cardiac surgical procedures were performed in 75 patients (48%). RESULTS: The operative mortality rate was 2.5% (2 of 81) for isolated mitral valve anterior leaflet repair and 3.8% (6 of 156) for all mitral valve anterior leaflet repair. Freedom from reoperation at 5 and 10 years was, respectively, 89.7% (n = 160) and 83.4% (n = 24) for the entire series of 558 patients, 91.9% (n = 51) and 81.2% (n = 10) for patients with anterior leaflet procedures, 88.8% (n = 109) and 84.4% (n = 14) for patients without anterior leaflet procedures and 91.7% (n = 118) and 88.9% (n = 18) for patients without rheumatic disease. Logistic regression showed that rheumatic origin of disease (odds ratio 2.99), but not anterior leaflet repair, increased the risk for reoperation. CONCLUSIONS: These results demonstrate that expansion of mitral valve techniques to include anterior leaflet disease yields immediate and long-term results equal to those seen in patients with posterior leaflet disease.

Follow-Up Studies↗
PubMed1993

Disposition of inhaled isobutene in F344/N rats.

Isobutene (2-methylpropene) (CAS No. 115-11-7) is a gas widely used in the chemical manufacturing industry. As an aid to planning long-term toxicity studies, research was conducted to determine the effect of exposure concentrations on the absorption and metabolism of isobutene in F344/N rats. Male F344/N rats (11-15 weeks of age) were exposed for 2 hr to 0, 40, 400, or 4000 ppm isobutene, and a time-course evaluation of blood levels of isobutene was performed using headspace analysis methods. Blood levels of isobutene were linearly related to exposure concentrations between 40 and 400 ppm but increased in a supralinear fashion at the highest concentration, suggesting that the capacity of the rats to metabolize isobutene had been exceeded. Total uptake, excretion patterns, and metabolic conversions were studied in rats exposed for up to 6 hr to 0, 2, 40, 400, or 4000 ppm [14C]isobutene. Absorption of the inhaled isobutene was approximately 8% up to 40 ppm isobutene, but decreased at the higher concentrations. The amount of isobutene metabolized per ppm.hr of exposure was also linear up to 40 ppm but decreased at higher concentrations. Over 90% of the absorbed isobutene was metabolized at exposure concentrations up to 400 ppm, but the exposure to approximately 4000 ppm isobutene resulted in approximately 20% of the absorbed dose exhaled as the unmetabolized isobutene. Two urinary metabolites were identified as isobutenediol and 2-hydroxyisobutyric acid. Two other urinary metabolites were tentatively identified as sulfate conjugates of isobutenediol. Based on these studies, linear dose-response relationships would be expected in chronic toxicity studies for exposures up to 40 ppm isobutene. Additional studies would be required to determine if repeated exposures would induce higher metabolic capacities in the exposed rats.

Administration, Inhalation↗
PubMed1992

Potential language and attentional networks revealed through factor analysis of rCBF data measured with SPECT.

We used changes in regional cerebral blood flow (rCBF) to disclose regions involved in central auditory and language processing in the normal brain. rCBF was quantified with a fast-rotating, single-photon emission computerized tomograph (SPECT) and inhalation of 133Xe. rCBF data were obtained simultaneously from parallel, transverse slices of the brain. The lower slice was positioned to include both Broca's and Wernicke's areas. The upper slice included regions generally regarded by neurobehaviorists as less related to primary auditory or linguistic functions. We presented three types of auditory stimuli to ten healthy, young volunteers: (a) diotically presented Danish speech, (b) dichotic word stimulation, and (c) white noise. Wilcoxon's signed ranks sum test revealed increased rCBF in language-related areas of cortex, viz., Wernicke's area and its right-sided homologous area as well as in Broca's area (left hemisphere), when subjects listened to narrative speech, compared to white noise (baseline). No significant rCBF differences were detected with this test during dichotic stimulation vs. white noise. A more sophisticated statistical method (factor analysis) disclosed patterns of functionally intercorrelated regions. The factor analysis reduced the highly intercorrelated rCBF measures from 28 regions of interest to a set of three independent factors. These factors accounted for 77% of the total variation in rCBF values. These three factors appeared to represent statistical analogues of independent brain networks involved in (I) auditory/linguistic, (II) attentional, and (III) visual imaging activity.

Acoustic Stimulation↗
PubMed1991

A force field evaluation tool for telephone service in ambulatory health care.

The tool presented here is useful in analyzing the constraints and capabilities of a health care telephone service. It also provides a systematic method for assessing systems problems. As part of our analysis, we recommended that the manager implement the following steps. First, the manager determines whether the driving force on the unit is continuity of care by an individual provider or consistency of response. This focus directly affects how the unit's telephone service can be best organized (i.e., decentralized or centralized) and clarifies the factors most needed for success. For example, to function effectively and efficiently, a centralized phone service needs strong provider-endorsed protocols. Second, the manager should carefully examine neutral constraint factors to determine methods to transform these constraints into capabilities, such as planning for extra staff or office hours (or both) during influenza season. Planning for extra hours or staff depends largely on whether budget and resource planning is done in advance and whether value is placed on customer access and satisfaction during peak demand periods. The manager must next determine whether the service delivery format (centralized or decentralized) is consistent with the force field analysis findings. If the findings are not consistent, can the analysis present a compelling argument for using the opposite approach? Finally, the manager must create a plan of action for minimizing the constraints revealed and maximizing existing capabilities to achieve the overall goal of excellent phone service. The process of analysis and creating a plan of action is an excellent opportunity to involve staff, providers, and administrators in efforts to achieve better health care telephone service for all customers.

Appointments and Schedules↗