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Biomedical subjects

M B Lee

Publications and source records attributed to M B Lee.

At least 37 records · Page 2Linked to original sources
PubMed1999

Power, self-care and health in women living in urban squatter settlements in Karachi, Pakistan: a test of Orem's theory.

This was a study of health in women living in urban squatter settlements in Karachi, Pakistan. The study grew out of the author's concern for the generally poor health status of Pakistani women. Orem's nursing theory was selected to examine health in these women. The purpose of the study was to examine relationships among basic conditioning factors, self-care agency (specifically, perception of power as a foundational capability of self-care agency and the enabling capabilities of self-care agency), self-care, and selected health outcomes of Pakistani women. Four hypotheses were developed and tested. They were that in a group of Pakistani women: (1) perception of power as a foundational capability and enabling capabilities of self-care agency and self-care will be related to selected basic conditioning factors; (2) perception of power, as a foundational capability of self-care agency, will be directly and positively related to enabling capabilities of self-care agency; (3) perception of power as a foundational capability and enabling capabilities of self-care agency will have a direct and positive relationship with self-care; and (4) self-care will be related to selected health outcomes. Hypotheses one, two and three were supported. Findings indicate that the basic conditioning factors, socioeconomic variables, ethnicity and roles, were predictive of perception of power, enabling capabilities of self-care agency, self-care and health. Hypothesis four was not supported; basic conditioning factors had more influence on health than self-care.

Adult↗
PubMed1998

Masked presentations of emotional facial expressions modulate amygdala activity without explicit knowledge.

Functional magnetic resonance imaging (fMRI) of the human brain was used to study whether the amygdala is activated in response to emotional stimuli, even in the absence of explicit knowledge that such stimuli were presented. Pictures of human faces bearing fearful or happy expressions were presented to 10 normal, healthy subjects by using a backward masking procedure that resulted in 8 of 10 subjects reporting that they had not seen these facial expressions. The backward masking procedure consisted of 33 msec presentations of fearful or happy facial expressions, their offset coincident with the onset of 167 msec presentations of neutral facial expressions. Although subjects reported seeing only neutral faces, blood oxygen level-dependent (BOLD) fMRI signal in the amygdala was significantly higher during viewing of masked fearful faces than during the viewing of masked happy faces. This difference was composed of significant signal increases in the amygdala to masked fearful faces as well as significant signal decreases to masked happy faces, consistent with the notion that the level of amygdala activation is affected differentially by the emotional valence of external stimuli. In addition, these facial expressions activated the sublenticular substantia innominata (SI), where signal increases were observed to both fearful and happy faces--suggesting a spatial dissociation of territories that respond to emotional valence versus salience or arousal value. This study, using fMRI in conjunction with masked stimulus presentations, represents an initial step toward determining the role of the amygdala in nonconscious processing.

Adult↗
PubMed1998

Screening of depression in patients with chronic medical diseases in a primary care setting.

BACKGROUND: Patients with chronic medical diseases may have depression that is not recognized by their primary care physicians. OBJECTIVES: We aimed to examine the application of Zung's Self-Rating Depression Scale (SDS) in the screening of depression in primary care patients with chronic medical diseases in a Chinese population. METHODS: We studied 268 patients with chronic medical diseases in the Family Medicine Outpatient Clinic using a structured questionnaire including basic demographic data, a Chinese version of the SDS and a rating for the self-perceived severity of physical condition. The severity of chronic medical diseases was assessed by the authors using the Duke University Severity of Illness Scale from a chart audit. Fifty patients were randomly selected for a diagnostic interview according to the DSM-IV criteria. The construct validity and internal consistency reliability, sensitivity and specificity of the SDS were examined. RESULTS: The results revealed that the SDS has good construct validity and internal consistent reliability in the evaluation of depression in Chinese patients with chronic medical diseases. A cut-off point of 55 had a sensitivity of 66.7% and a specificity of 90.0%. Depressed patients reported more cognitive symptoms than depressed affect and physical symptoms. Female patients had more severe depressed affect than male patients, but males had more prominent diurnal variation of mood than females. CONCLUSIONS: We concluded that SDS can be a good screening tool for depression in Chinese patients with chronic medical diseases. Owing to constraints in the expression of sexual desire in the Chinese, elderly subjects tended to report loss of libido in the response to the SDS.

Adult↗
PubMed1998

Effect of allogeneic freeze-dried demineralized bone matrix on regeneration of alveolar bone and periodontal attachment in dogs.

This split-mouth study was designed to evaluate regeneration of alveolar bone and periodontal attachment following implantation of allogeneic, freeze-dried, demineralized bone matrix (DBM). Buccal fenestration defects (6x4 mm) were created on the maxillary canine teeth in 6 beagle dogs. DBM was implanted into one randomly selected defect in each animal. The contralateral defect served as surgical control. Tissue blocks were harvested following a 4-week healing interval and prepared for histometric analysis. DBM was discernible in all implanted defects with limited evidence of bone metabolic activity. The DBM particles appeared invested within a dense connective tissue, often in close contact to the instrumented root. Fenestration defect height averaged 3.8+/-0.1 and 3.7+/-0.3 mm, total bone regeneration 0.9+/-0.9 and 0.4+/-1.2 mm, and total cementum regeneration 2.3+/-1.5 and 0.6+/-0.7 mm for DBM and control defects, respectively. Differences with regards to cementum regeneration were statistically significant (p=0.03). In summary, the results of this study suggest that DBM implants may enhance cementum regeneration in this defect model, and that they have no apparent effect on alveolar bone regeneration. Enhanced cementum regeneration may be possibly be explained by provisions for guided tissue regeneration from the implant suppressing a significant influence of the gingival connective tissue on the healing process. Moreover, a 4-week healing interval appears insufficient for turnover of DBM.

Alveolar Bone Loss↗
PubMed1998

Periodontal repair in dogs: effect of recombinant human transforming growth factor-beta1 on guided tissue regeneration.

This study evaluated alveolar bone and cementum regeneration following surgical implantation of recombinant human transforming growth factor-beta1 (rhTGF-beta1) in conjunction with guided tissue regeneration (GTR). Supraalveolar, critical size, periodontal defects were surgically created around the 3rd and 4th mandibular premolar teeth in right and left jaw quadrants in 5 beagle dogs. Alternate jaw quadrants in consecutive animals received rhTGF-beta1, in a CaCO3/hydroxyethyl starch carrier with GTR, or carrier with GTR alone (control). 20 microg of rhTGF-beta1 in buffer solution was incorporated into approximately 0.8 ml of carrier for each defect scheduled to receive rhTGF-beta1. Animals were sacrificed at week 4 postsurgery and tissue blocks were harvested and processed for histometric analysis. Clinical healing was generally uneventful. Minor membrane exposures were observed. Defects with membrane exposure displayed an inflammatory infiltrate underneath the membrane. Bone regeneration of trabecular nature, apparent in all animals, was generally limited to the very apical aspect of the defects. Cementum regeneration was limited without obvious differences between experimental conditions. Comparing rhTGF-beta1, to control defects, statistically significant differences were found for area (1.8+/-0.4 and 1.3+/-0.6 mm2, respectively; p<0.05) and density (0.3+/-0.1 and 0.2+/-0.03, respectively; p<0.05) of alveolar bone regeneration. Observed differences are small and represent a clinically insignificant potential for enhanced regeneration in this preclinical model. Within the limitations of study, it may be concluded that rhTGF-beta1 has a restricted potential to enhance alveolar bone regeneration in conjunction with GTR.

Alveolar Bone Loss↗
PubMed1998

Effect of allogenic freeze-dried demineralized bone matrix on guided tissue regeneration in dogs.

This randomized, split-mouth study was designed to evaluate the adjunctive effect of allogenic, freeze-dried, demineralized bone matrix (DBM) to guided tissue regeneration (GTR). Contralateral fenestration defects (6 x 4 mm) were created 6 mm apical to the buccal alveolar crest on maxillary canine teeth in 6 beagle dogs. DBM was implanted into one randomly selected fenestration defect. Expanded polytetrafluoroethylene (ePTFE) membranes were used to provide bilateral GTR. Tissue blocks including defects with overlying membranes and soft tissues were harvested following a four-week healing interval and prepared for histometric analysis. Differences between GTR+DBM and GTR defects were evaluated using a paired t-test (N = 6). DBM was discernible in all GTR+DBM defects with limited, if any, evidence of bone metabolic activity. Rather, the DBM particles appeared solidified within a dense connective tissue matrix, often in close contact to the instrumented root. There were no statistically significant differences between the GTR+DBM versus the GTR condition for any histometric parameter examined. Fenestration defect height averaged 3.7+/-0.3 and 3.9+/-0.3 mm, total bone regeneration 0.8+/-0.6 and 1.5+/-0.8 mm, and total cementum regeneration 2.0+/-1.3 and 1.6+/-1.7 mm for GTR+DBM and GTR defects, respectively. The histologic and histometric observations, in concert, suggest that allogenic freeze-dried DBM has no adjunctive effect to GTR in periodontal fenestration defects over a four-week healing interval. The critical findings were 1) the DBM particles remained, embedded in dense connective tissue without evidence of bone metabolic activity; and 2) limited and similar amounts of bone and cementum regeneration were observed for both the GTR+DBM and GTR defects.

Alveolar Bone Loss↗
PubMed1998

Stress-reducing effect of physician's tape-recorded support on cardiac surgical patients in the intensive care unit.

Staying in an intensive care unit (ICU) is very stressful for patients after heart surgery. Although it is a general belief that support from doctors is important to reduce patients' tension, no quantitative data are available. We investigated the stress-reducing effects of a tape-recorded message from the physician which provided information regarding the surgery and emotional support for heart surgery patients postoperatively in the ICU. Sixty patients who underwent cardiac surgery were randomly allocated to two equal groups. The patients in the experimental group listened to a tape-recorded message from their attending surgeon soon after they recovered from anesthesia, while the control group rested during the study period. The effectiveness of the tape-recorded support program was evaluated by the influence on heart rate, blood pressure, and finger skin temperature, as well as the degree of subjective pain, tension, anxiety, depression, and anger. The pain and tension levels of the patients were measured using a visual analogue scale, while the severity of anxiety, depression, and anger was evaluated using the Brief Symptom Rating Scale. Patients' evaluation of the usefulness of the program was also assessed. After listening to the physician's recorded message, the mean increase in the skin finger temperature in the experimental group was higher than in the control group (0.44 degree C vs 0.25 degree C, p = 0.0513). The experimental group had significant decreases in their mean scores of pain (-1.11 vs 0.36, p = 0.0043), tension (-2.26 vs -0.25, p = 0.0001), anxiety (-1.3 vs -0.57, p = 0.0473), and depression (-2.24 vs -0.37, p = 0.0253). The patients showed a high need for this support program (mean need score 8.4). These findings show that a physician's tape-recorded message providing information and emotional support can reduce stress in heart surgery patients in the ICU postoperatively.

Cardiac Surgical Procedures↗
PubMed1997

Bone morphogenetic proteins: background and implications for oral reconstruction. A review.

For over 30 years now, research has been carried out to isolate and purify bone morphogenetic protein (BMP), a substance which has been shown to induce heterotopic bone formation in various animal species. Recent advances in the fields of developmental biology, molecular biology, genetics and wound healing, have shown that the BMPs are not only responsible for postfetal bone induction (including normal bone remodeling, healing and repair), but are also critical during embryogenesis, not only in regards to the skeletal system, but quite possibly in the morphogenesis and pattern formation of other tissues and organs as well. Therefore, BMPs have the potential as a therapeutic utility in orthopedic and dento-alveolar reconstruction.

Animals↗
PubMed1996

Poor reproducibility in radiographic grading of femoral cementing technique in total hip arthroplasty.

The first study of the reproducibility of a widely accepted grading system for femoral cementation in total hip arthroplasty is reported. Sixty postoperative radiographs were graded on two occasions at least 2 weeks apart by two experienced observers. The test-retest reproducibility rate was 60% for observer 1 and 70% for observer 2. The interobserver reproducibility varied between 60 and 63% for the different assessments. Between 5 and 6% of cases differed by more than one grade between tests. Kappa statistical analysis confirmed that reproducibility was poor in all cases. This cement grading system, even in the hands of experienced observers, has too high a rate of intraobserver and interobserver error to recommend its use.

Bone Cements↗
PubMed1995

Measurement of rabbit intraocular pressure with the Tono-Pen.

A Tono-Pen-1 (TP-1) and a Tono-Pen-2 (TP-2) were calibrated against direct manometry in the eyes of living rabbits to determine the accuracy of the Tono-Pen. Eighteen normal eyes of 10 rabbits were cannulated and connected to a pressure transducer with a chart recorder. Intraocular pressure (IOP) was increased from 5 to 40 mm Hg in 5-mm-Hg increments and from 40 to 80 mm Hg in 10-mm-Hg increments. After each incremental increase, IOP was measured first with a TP-1 and then with a TP-2. Plotting the mean Tono-Pen readings for each eye against the transducer pressure produced the following two regression line formulas: y = -0.613+0.790x (r2 = 0.97) for TP-1, and y = -1.45+0.824x (r2 = 0.97) for TP-2. Neither regression line was statistically different; p = 0.2 for the two slopes, and p = 0.24 for the y-axis intersection. The TP-1 and TP-2 can be used to rapidly and accurately measure the IOP in normal rabbit eyes. Tono-Pen readings do, however, significantly underestimate pressures in the range of 5-80 mm Hg. A table with 95% confidence intervals for corrected IOP readings obtained with the TP-1 or -2 is provided.

Animals↗
PubMed1995

Periodontal repair in dogs: recombinant human bone morphogenetic protein-2 significantly enhances periodontal regeneration.

This study evaluated bone and cementum regeneration following periodontal reconstructive surgery using recombinant human bone morphogenetic protein-2 (rhBMP-2) in six beagle dogs. Surgically created mandibular supraalveolar premolar tooth defects in contralateral jaw quadrants were randomly assigned to receive rhBMP-2 or control vehicle. Clinical defect height was prepared to 5 mm. rhBMP-2 was applied with synthetic bioerodable particles and autologous blood using 20 micrograms rhBMP-2 per 100 microliters implant volume. Flaps were advanced to submerge the teeth and sutured. The dogs were sacrificed 8 weeks postsurgery. Histometric recordings included defect height, height and area of alveolar bone regeneration, height of cementum regeneration, root resorption, and ankylosis. Group means, standard deviations, and P values are shown (Student t test; n = 6). Histometric defect height for rhBMP-2 and control defects was 3.7 +/- 0.3 and 3.9 +/- 0.4 mm, respectively (P = 0.446). Height of alveolar bone regeneration amounted to 3.5 +/- 0.6 and 0.8 +/- 0.6 mm for rhBMP-2 and control defects, respectively (P = 0.000). Corresponding values for bone area were 8.4 +/- 4.5 and 0.4 +/- 0.5 mm2, respectively (P = 0.006). Cementum regeneration was observed in all experimental defects (17/17) and in 15 out of 17 controls, averaging 1.6 +/- 0.6 and 0.4 +/- 0.3 mm for rhBMP-2 and control defects, respectively (P = 0.005). Small amounts of root resorption were seen in rhBMP-2 defects, whereas controls exhibited substantial resorption (0.2 +/- 0.1 and 1.1 +/- 0.3 mm, respectively; P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Bone Loss↗
PubMed1995

Periodontal regenerative potential of space-providing expanded polytetrafluoroethylene membranes and recombinant human bone morphogenetic proteins.

A concept of space provision to support skeletal repair has long been used in orthopedic and oral maxillofacial reconstructive therapy. More recently, this concept has been studied and adapted to periodontal reconstructive therapy. Other studies have demonstrated that skeletal tissues represent a significant reservoir of growth factors, including bone morphogenetic proteins. Such factors have been shown to stimulate skeletal repair in preclinical models and in clinical defects. We herein review studies using the critical size supraalveolar periodontal defect model in which clinically meaningful periodontal regeneration was achieved following reconstructive surgery, including space provision by reinforced expanded polytetrafluoroethylene membranes or including surgical implantation of recombinant human bone morphogenetic protein-2. Potential mechanisms involved in observed regeneration are discussed.

Bone Morphogenetic Proteins↗
PubMed1995

Dynamics of wound healing in periodontal regenerative therapy.

Experimental animal and clinical studies have increased understanding of the biology of healing following periodontal regenerative therapy and factors that may influence the outcome. Formation of a new connective tissue attachment rather than a long junctional epithelium at the tooth-gingival flap interface is dependent upon the completion of a series of interactions among the root surface, plasma and tissue factors, and the connective tissue of the gingival flap. First, plasma proteins must adsorb to and remain in undisturbed contact with a generally noncompromised root surface. Next, adhesion of the established fibrin clot to the root surface must remain intact. Within days, a cellular and fibrous attachment will form; however, the tooth-gingival flap interface will still be vulnerable to wound-rupturing forces. Within two weeks the interface may have gained sufficient mechanical strength to offset such forces, at least in limited periodontal defects. Eventually, maturation of the fibrous attachment, including bone and cementum formation, will occur, particularly following adequate space provision by barrier membranes (guided tissue regeneration). A novel research focus involves how advances in molecular biology can translate to periodontal regenerative therapy. Bone morphogenetic proteins (BMPs) have been shown to support healing in a variety of skeletal sites. Recent research has demonstrated clinically significant alveolar bone and cementum regeneration with the use of a recombinant human BMP-2 implant. Such data suggest that growth-promoting substances, such as rhBMP-2, may significantly enhance periodontal regeneration and that use of such substances may radically recast current periodontal regenerative therapy.

Animals↗
PubMed1994

Echographic findings in infectious endophthalmitis.

OBJECTIVE: To correlate the initial echographic findings in eyes with infectious endophthalmitis with the visual prognosis and causative microorganism. DESIGN: A retrospective review of the clinical and standardized ocular echographic findings in eyes with infectious endophthalmitis was performed. SETTING: University-based ophthalmology department. STUDY PARTICIPANTS: One hundred thirty-seven eyes (136 patients) with infectious endophthalmitis that were evaluated by the ocular echography service of the Doheny Eye Institute, Los Angeles, Calif, between January 1, 1981, and December 31, 1992. RESULTS: Four findings on initial echography were associated with poor initial vision: dense vitreous opacities, retinal detachment, macular detachment, and choroidal detachment. Five findings on initial echography correlated with poor final vision: dense vitreous opacities, vitreous membranes, the presence of retinal detachment, the extent of retinal detachment, and the presence of choroidal detachment. Change (decrease) in vision during the follow-up period was associated with the presence of combined vitreous and subhyaloid opacities, retinal detachment, and choroidal detachment. All eyes with initially clear vitreous on ocular echography had either early streptococcal or culture-negative endophthalmitis. Advanced streptococcal endophthalmitis correlated with the most severe vitreous inflammation, vitreous membranes, and the most extensive posterior vitreous detachment, whereas gram-negative endophthalmitis correlated with choroidal detachment on initial echography. Stepwise logistic regression analysis revealed that the presence of choroidal detachment, not gram-negative microorganisms, was the principal predictor of poor visual outcome in these eyes. CONCLUSION: Ocular echography is a useful method in the clinical evaluation and treatment of infectious endophthalmitis, especially in eyes with opaque media.

Adolescent↗
PubMed1994

Anaerobic flora of the conjunctival sac in patients with AIDS and with anophthalmia compared with normal eyes.

Relatively few investigations of anaerobic bacteria as ocular flora have been conducted, and their results have been contradictory. The conjunctival sacs of 22 normal subjects and of 14 patients with acquired immunodeficiency syndrome, and 22 anophthalmic sockets were cultured for anaerobic bacteria Thirty-four (77.3%) of the 44 eyes of normal subjects harbored anaerobic bacteria; Propionibacterium acnes was present in 28 eyes (63.6%), Lactobacillus species in 6 eyes (13.6%), and Veillonella species in 7 eyes (15.9%). The finding were very similar for anophthalmic sockets (p = 0.01), with 17 (77.3%) of the 22 sockets harboring anaerobes; Propionibacterium acnes was the organism identified in 16 (72.7%) of these sockets; Veillonella was identified in 4 (18.1%), Peptococcus niger in 3 (13.6%) and P. granulosum in 2 (9.0%) of these sockets. Acquired immunodeficiency syndrome patients had the highest incidence of anaerobic organisms, with positive cultures obtained from 24 (85.7%) of the 28 eyes. Propionibacterium species were isolated from 16 (57.1%) of these eyes. Clostridium species from 10 (35.7%) eyes and Actinomyces species from 8 (28.6%) eyes. It thus appears that anaerobic organisms are common flora in normal conjunctival sacs and in anophthalmic sockets, as well as in the sacs of acquired immunodeficiency syndrome patients, but the latter group had a higher incidence (x2 = 0.87) and a spectrum of organisms that was different from that of the other two groups.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The politics of pharmaceutical reform: the case of the Philippine National Drug Policy.

A national drug policy was formulated in the Philippines after the rise of the Aquino government in 1986. In this article, the author discusses the pharmaceutical situation before the policy was announced, and argues that the major push for a policy came from the confluence of four factors: a change in the structures of political power, especially the rise of a new government and the empowerment of health non-governmental organizations as new participants in the policy process; members of the Department of Health who pushed for a policy; a more conductive social and political climate, both locally and internationally; and a growing body of knowledge about the drug issue. The author discusses the policy's achievements as well as the limitations that have beset the policy from 1987 to 1992.

Costs and Cost Analysis↗
PubMed1994

Modification of the glaucoma drainage implant to prevent early postoperative hypertension and hypotony: a laboratory study.

Hypotony or hypertension in the early postoperative period following implantation of a nonvalved seton such as the Molteno tube is a common problem. We conducted a laboratory investigation evaluating two modifications of the silicone drainage tube. One involved a longitudinally-oriented, pressure-sensitive slit-valve combined with an absorbable occluding ligature interposed between the valve and the episcleral plate. Experiments examining the relationship between slit length, opening pressure, and flow rate were performed. The second modification involves focally constricting the lumen of the tube with an external ligature in order to reduce flow rates. Our results indicate that a slit-valve length of 2.0 mm appears to provide a reliable opening pressure of around 10 mm Hg, with relatively high flow when pressures exceed opening pressure. Focally constricting the lumen of the tube, however, was shown to be both unpredictable and unsatisfactory for reducing the flow of fluid to a range consistent with steady state aqueous production.

Drainage↗