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Biomedical subjects

M B Lee

Publications and source records attributed to M B Lee.

At least 19 recordsLinked to original sources
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↗
PubMed1992

Fractionated doses of ionizing radiation alter postprandial small intestinal motor activity.

We investigated the effects of total abdominal fractionated irradiation on postprandial small intestinal motor activity in five dogs. Five strain-gauge transducers were attached to the seromuscular layer of the duodenum, jejunum, and ileum of each dog to record circular muscle contractions. Radiation (250 cGy) was administered three times a week on alternate days for three successive weeks (total dose, 2250 cGy). Postprandial 4-hr recordings were made once each week during radiation and at one and three weeks following completion of radiation. Duodenal mean amplitude and area under contractions did not change during or following the radiation schedule, but the mean frequency and duration of duodenal contractions decreased during the radiation schedule. Both parameters returned to baseline values postirradiation. Jejunal mean duration, amplitude, area, and frequency of contractions decreased during radiation; mean amplitude and area returned to baseline values postirradiation but not the duration and frequency of contractions. All parameters of ileal contractions decreased during radiation, and all but area and amplitudes remained depressed postirradiation. Significantly decreased strength and frequency of contractions, particularly in the jejunum and ileum occur during and following irradiation. These changes may potentially alter transit time.

Animals↗
PubMed1992

Which is better? One or two? A randomized clinical trial of single-plate versus double-plate Molteno implantation for glaucomas in aphakia and pseudophakia.

PURPOSE: Previous studies have suggested that primary double-plate Molteno implantation may be beneficial. Therefore, the authors performed a randomized clinical trial to evaluate the relative effectiveness and safety of single- versus double-plate Molteno implantation. METHODS: From March 1988 to February 1990, 132 patients who underwent Molteno implantation for medically uncontrollable non-neovascular glaucomas in aphakia or pseudophakia were randomly assigned to receive either single- or double-plate implants. RESULTS: The 1- and 2-year life-table success rates (success [survival] defined as 6 mmHg < or = final intraocular pressure [IOP] < or = 21 mmHg without additional glaucoma surgery or devastating complication) were 55% and 46% with single-plate implantation and 86% and 71% with double-plate implantation, respectively. The final postoperative visual acuities were within one line of the preoperative visual acuities or had improved in 73% and 80% of patients, respectively. Choroidal hemorrhages and/or effusions, corneal decompensation, flat anterior chambers, and phthisis bulbi were more common in the patients who had undergone double-plate Molteno implantation; however, transient elevations of IOP during the first few postoperative months were more common in the patients who had undergone single-plate Molteno implantation. CONCLUSIONS: Double-plate Molteno implantation more frequently affords IOP control than single-plate Molteno implantation; however, double plates are associated with greater risks of choroidal hemorrhages and/or effusions, corneal decompensation, flat anterior chambers, and phthisis bulbi.

Adolescent↗
PubMed1992

Clinical experience with the single-plate Molteno implant in complicated glaucomas. Update of a pilot study.

Ninety-six patients who had undergone single-plate Molteno implantation for glaucomas with poor surgical prognoses were re-evaluated for long-term results. Control of intraocular pressure was achieved with one single-plate implant to a level less than 22 mmHg (but greater than 5 mmHg) without reoperation or devastating complications in 46% of the aphakic/pseudophakic eyes, 25% of eyes after failed filters, 25% of eyes with neovascular glaucomas, and 26% of eyes in patients younger than 13 years of age (life-table analysis at 5 years). Five-year success rates improved to 53%, 71%, 40%, and 56%, respectively, when data from second plates were included. Visual acuities improved or remained the same after one or two plates were implanted in 47% of aphakic/pseudophakic eyes, 17% of eyes after failed filters, 65% of eyes with neovascular glaucomas, and 63% of eyes in patients younger than 13 years of age on whom Snellen acuity was available. The most frequent overall complications after implantation of one or two plates included: corneal edema (19%), corneal graft decompensation (13%), and cornea-tube touch, retinal detachment, and cataract (8% each).

Adolescent↗
PubMed1991

Repair of retinal detachment caused by cytomegalovirus retinitis in patients with the acquired immunodeficiency syndrome.

Twenty-two eyes of 19 patients with the acquired immunodeficiency syndrome who had pars plana vitrectomy and silicone-oil injection after retinal detachment caused by cytomegalovirus retinitis were studied. All patients but one were monitored until time of death. The postoperative survival time and the factors that predicted anatomic success (retinal attachment) and functional success (visual acuity) were analyzed. No intraoperative complications were encountered. The mean survival time after surgery was four months. Of all of the preoperative and intraoperative factors studied, only the duration of cytomegalovirus retinitis was predictive of survival (P less than .03). The anatomic success rate was 89.5% (17 of 19 patients). None of the factors showed a trend or statistical significance in relation to anatomic success. Fifteen of 19 patients (79%) had lost at least two lines of Snellen visual acuity at time of death. Vision declined in a bimodal pattern (within the first postoperative month and after four months postoperatively). The optic nerve was pink and well perfused preoperatively in 16 of 19 patients (81.8%), but optic-nerve atrophy was observed postoperatively in 18 of 19 patients (95.5%). There was a trend for functional success to be influenced by increased intraocular pressure and optic-nerve atrophy, although our sample size was too small for statistical significance.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Synthesis of extracellular matrix by macrophage-modulated retinal pigment epithelium.

In proliferative vitreoretinopathy, macrophages and retinal pigment epithelial cells are associated with microfibrillar matrix proteins in the vitreous cavity, but the contribution of this extracellular matrix to the pathophysiology is not known. We used radiolabeling techniques on cultured human retinal pigment epithelial cells to correlate the secretion of extracellular matrix proteins with macrophage-induced modulation of cell proliferation and morphologic features. Retinal pigment epithelial cells incubated in a macrophage-conditioned medium assumed fibrocytelike morphologic characteristics, grew faster, and exhibited a decreased cellular release of fibrillar and nonfibrillar matrix components. However, due to a simultaneous greater increase in cell numbers in these modulated cultures, the total production of fibrillar and nonfibrillar matrix components by the culture population was increased.

Cell Division↗
PubMed1991

Surfactant replacement therapy in respiratory distress syndrome. Meta-analysis of clinical trials of single-dose surfactant extracts.

Replacement therapy with surfactant extracts in premature infants with respiratory distress syndrome has been evaluated in several clinical trials. The results of individual trials do not provide conclusive evidence that administration of a single dose of surfactant improves morbidity or mortality. Meta-analysis is a statistical method to combine the results of such clinical trials, and combined analysis provides a means to overcome the problem of not being able to detect significant small differences in individual trials due to these small sample sizes. Seven clinical trials (277 patients treated with nonhuman surfactant extract and 263 controls) met the criteria for analysis; five outcome measurements (mortality, patent ductus arteriosus, pneumothorax, intraventricular hemorrhage, and bronchopulmonary dysplasia) were selected to estimate the treatment effect. The meta-analysis showed that a single dose of surfactant administered before the first breath or within 15 hours of birth significantly decreased the mortality rate (95% confidence interval = -0.19 to -0.03) and the risk of developing pneumothorax (95% confidence interval = -0.28 to 0.14) in infants with respiratory distress syndrome. Further clinical trials are needed to evaluate other aspects of surfactant replacement therapy in premature infants because inconsistent results were observed among the seven analyzed studies.

Confidence Intervals↗
PubMed1991

Gastrointestinal motor effects of erythromycin in humans.

The effects of an antibacterially effective IV dose of erythromycin on gastrointestinal motor activity were investigated in eight normal healthy human volunteers in the fasted state and the fed state. Motor activity was recorded by a multilumen manometric tube. Data were analyzed visually and by a computer method. Blood samples were obtained for erythromycin and motilin assays. In the gastric antrum, erythromycin significantly increased the total duration, amplitude, and area under contractions from 0 to 60 minutes and frequency of contractions from 0 to 30 minutes from the start of its infusion in the fasted state. A similar response in the fed state occurred mostly from 0 to 30 minutes after the start of erythromycin infusion. By contrast, erythromycin inhibited the frequency and decreased the duration of small intestinal contractions in the fed state but had no effect in the fasted state. The gastric motor response was related to the plasma concentration of erythromycin, but not to plasma motilin. Erythromycin significantly shortened the duration of migrating motor complex disruption by a meal. Erythromycin also induced symptoms of upper abdominal pain, bloating, and nausea. Abdominal pain was related to strong antral contractions in both fasted and fed states; bloating occurred only in the fed state. Nausea occurred in both fasted and fed states, but it was not related to any specific pattern of motor activity. It is concluded that the strong antral contractions induced by erythromycin may accelerate the rate of gastric emptying, but they may also be responsible for causing the sensations of upper abdominal pain and bloating. The motor response to erythromycin is less during the fed than during the fasted state. The strong antral contractions induced by erythromycin are not mediated by the release of motilin.

Abdominal Pain↗
PubMed1991

Duration of response to intramuscular versus low dose intradermal hepatitis B booster immunization.

OBJECTIVE: To determine the duration of the immune response to plasma-derived hepatitis B vaccine among healthcare workers responding to booster doses of intradermal (ID) or intramuscular (IM) vaccine in 1986 and those with protective levels of antibody to hepatitis B surface antigen (anti-HBs) in 1986 without booster vaccine. Both groups received a primary hepatitis B vaccine series 24 to 36 months earlier. DESIGN: Cross-sectional follow-up study two years later of an inception cohort defined in 1986. SETTING: An academically affiliated metropolitan county hospital. PARTICIPANTS: Group 1: Hospital employees responding to booster doses of hepatitis B vaccine given ID or IM in 1986 due to low anti-HBs levels. Forty-one (82%) of 50 eligible persons were evaluated. Group 2: Persons not receiving booster vaccine in 1986 due to protective levels of anti-HBs. A random sample of 95 persons was drawn from a pool of 152 participants with protective levels in 1986. Sixty-five (68%) of 95 contacted persons were restudied. RESULTS: In 1988, 14 (64%) of 22 previous ID responders had anti-HBs levels greater than or equal to 10 milli-international units (mIU)/mL, compared with 17 (89%) of 19 IM responders (p = .055). The 1988 geometric mean titer of IM recipients was 66.4 +/- 4.5 mIU/mL and of ID recipients was 20.7 +/- 7.4 (p = .04). None of 65 Group 2 subjects' anti-HBs titers dropped below 10 mIU/mL by 1988. CONCLUSIONS: Plasma-derived hepatitis B vaccine recipients with anti-HBs levels greater than or equal to 10 mIU/mL at 24 to 36 months after primary immunization are likely to maintain these levels two years later. The diminished durability of the antibody response together with the increased rate of local side effects associated with the ID injection route may limit its applicability as an alternative to using IM booster doses of hepatitis B vaccine.

Follow-Up Studies↗
PubMed1991

Trichotillomania: a clinical study of 36 patients.

To understand the clinical characteristics of trichotillomania, 36 patients were investigated at the psychocutaneous special clinic from February 1982 to October 1990. There were 16 males and 20 females. The most prominent age was found in a group of 23 (63.9%) elementary school children, and in regards to the age of disease onset, 35 (97.2%) of our patients were under the age of 18. A 30-year-old woman with schizophrenia and a 6-year-old boy with mental retardation were noted in our study; the remaining 34 patients were generally well without signs of mental illness except for the recurrent failure to resist impulses to pull out their own hair. The common life events precipitating stress were academic problems and parent-child conflicts. The duration of follow-up was for at least 6 months. The habit of hair plucking was easily corrected if the duration of the disease was less than 6 months. Usually these patients had a satisfactory regrowth of hair within 1-3 months after our explanation and reassurance. In contrast, the patients with a hair loss of more than half a year were not easy to approach, and needed psychiatric treatment.

Adolescent↗
PubMed1990

Properties of GABA-activated whole-cell currents in bipolar cells of the rat retina.

This paper describes experiments on GABA-activated whole-cell membrane currents in bipolar cells freshly isolated from the adult rat retina. The main goal was to determine whether bipolar cell responses to GABA could be resolved in terms of mediation by the GABAA receptor, the GABAB receptor, or both. Bipolar cells were isolated by gentle enzymatic dissociation and identified by their distinct morphology. GABA agonists and antagonists were applied focally by pressure and the resultant currents were recorded under whole-cell voltage clamp. In all bipolar cells tested, GABA (0.1-100 microM) induced a monophasic response associated with a conductance increase (IGABA). The shift in reversal potential for IGABA as a function of pipet [Cl-] paralleled that predicted based on the Nernst equation for Cl-. IGABA was mimicked by muscimol (5-20 microM) and antagonized by bicuculline (20-100 microM). Baclofen (0.1-1.0 mM) produced no apparent conductance change. "Hot spots" of sensitivity to GABA which might be associated with regions of synaptic contact were not found; both the soma and processes of all bipolar cells were responsive to focally applied GABA. Furthermore, all bipolar cells tested responded to glycine. In conclusion, we have established the presence of GABAA receptors on rat retinal bipolar cells. Our data suggest further that these cells lack GABAB receptors. Finally, our observation that bipolar cells in the rat retina are relatively homogeneous in terms of their sensitivity to GABA and glycine lead us to postulate that the functional significance of the presence of receptors and their distribution on a neuron may be dictated more by the topography of the presynaptic inputs than by its inherent chemosensitivity.

Animals↗
PubMed1990

[Life quality of post-myocardial infarction patients: influence of personal variables on coping].

Coping in terms of physical, social, and psychological well-being and health-seeking behavior were studied by a self-reported questionnaire in 233 outpatients with myocardial infarction below 70 years of age. For most of these patients, physical limitations or discomfort were not significant, but the impacts on their emotion and social life were rather severe. As to social maladjustment, 70.3% of the patients were experiencing a deteriorated sexual life, 63.9% had not returned to their prior work status, 55.6% had decreased social participation and 45.7% had less interest in leisure activities. Physical morbidity was not the only determinant of maladaptation. Sex, educational level, existence of combined chronic disease, the time interval, and premorbid occupational characteristics all appear to be salient factors for coping. Those patients with a lower educational level were prone to the prominent threat of the disease (perceived lack of control and predictability), had higher scores of psychiatric symptoms, reported more physical symptoms, had a lower rate of work resumption and showed poorer medical compliance. Such data indicates that differences in disease-perception may be the mediators of socioenvironmental and illness-related influences. The rate of work resumption was also directly proportional to the patients' socioeconomic status and the degree of premorbid work responsibility and psychological demand reported by patients. Poorer outcomes of coping were also related to time interval since first heart attack and combined diabetes mellitus. Recovery from myocardial infarction is more than just a medical problem. Biomedical and psychosocial variables interact at many levels in the recovery process. It is of considerable practical importance to recognize the patients' coping ability, in order to obtain effective comprehensive care.

Adaptation, Psychological↗
PubMed1990

[Clinical evaluation of psychiatric disorders among first-visit patients to a primary care unit].

It is important for a primary care physician to know the most common psychiatric diagnoses, criteria for these diagnoses, and proper treatment. During a 4-month period from December 1987 to March 1988, the authors conducted this prospective study in a rural group practice center and investigated 189 first-visit patients aged from 16 to 60 years. Among them, 55 cases (29.1%) were diagnosed as having psychiatric disorders which included: psychological factors affecting physical condition, 29 cases; generalized anxiety disorder, 12 cases; adjustment disorder, 10 cases; and others, 4 cases. There were no significant differences in marital status, social class, or family structure between patients with and without psychiatric disorders. However, the patients with psychiatric disorders tended to have a longer duration of illness, to exhibit more salient features of introversion and neuroticism in their personalities, to show poorer family function and to experience more stressful life events. Although all the psychiatric patients presented somatic symptoms as their primary complaints, we also found that they reported significantly higher scores for psychiatric symptoms on a self-rating scale. This study demonstrates that in order to promote comprehensive primary health care, psychiatry and behavioral science are essential training curricula for family physicians.

Adolescent↗
PubMed1990

[Psychosocial aspect of somatic complaints in patients after myocardial infarction].

The aim of this study was to explore the association between psychosocial variables and somatic complaints in terms of the biopsychosocial model. The analysis showed that both socioeconomic and psychological variables play a prominent role in the subjective complaints of coronary symptoms as follows: (1) Functional class: A low occupational index was found to be a predictor of much disability. Subjects with higher self-ratings of psychiatric symptoms (i.e. phobia, depression, interpersonal hypersensitivity), lower personal well-being (i.e. esteem, competence), and major social maladaptation had significantly more disability. (2) Chest pain: Patients with a higher morbidity of chest pain were more likely to be female, have less education, have more social maladjustment, and have less social support. Higher scores of psychiatric symptoms (i.e. anxiety, depression, hostility) and a perception of threatening by others were highly correlated with the severity of chest discomfort. Physicians should be aware of the ways in which psychosocial and biomedical variables may interact at many levels, especially for the patients with unexplained physical symptoms or social dysfunction.

Adaptation, Psychological↗
PubMed1990

Reliability and validity of using a Brief Psychiatric Symptom Rating Scale in clinical practice.

To develop a reliable and valid psychiatric self-rating scale for use in medical practice, the authors modified Derogatis' Symptom Check List-90-R (SCL-90-R) and designed a shorter form, named Brief Symptom Rating Scale (BSRS). The BSRS comprises 50 items, which best reflect the original ten symptom dimensions and three indices of psychopathology from the SCL-90-R. The BSRS has been proven in different populations to have an excellent split-half reliability as well as good internal structure according to factor analysis. In addition, BSRS scores are highly correlated with the parental form SCL-90-R among medical populations for each symptom dimension and the three indices. The rate of accurate classification for BSRS between psychiatric and nonpsychiatric cases was 75.8%, with a sensitivity of 66.7% and a specificity of 86.7% by discriminant analysis based on 10 dimensional scores obtained from 1,638 subjects, randomly selected from the Psychiatric Outpatient Clinic, the Family Medicine Clinic and nonpsychiatric medical inpatients. Therefore, the BSRS is a satisfactory global measure and case-finding screening instrument for psychopathology in both psychiatric and nonpsychiatric medical settings.

Adult↗
PubMed1989

Marrow transplantation for acute lymphoblastic leukemia: factors affecting relapse and survival.

Transplant outcome was analyzed in 690 recipients of bone marrow transplants (BMTs) for acute lymphoblastic leukemia (ALL) in first (n = 299) or second remission (n = 391). Actuarial 5-year leukemia-free survival was 42% +/- 9% (95% confidence interval) and 26% +/- 6%, respectively; relapse rates were 29% +/- 9% and 52% +/- 8%, respectively. Five-year leukemia-free survival was 56% +/- 18% in children and 39% +/- 10% in adults (P less than .02) transplanted in first remission. In first-remission adults, non-T-cell phenotype, male to female donor-recipient sex-match and graft-v-host disease (GVHD) were associated with decreased leukemia-free survival; inclusion of corticosteroids in the regimen to prevent GVHD was associated with increased leukemia-free survival. Variables associated with decreased leukemia-free survival after second-remission transplants were age greater than or equal to 16 years and relapse occurring while on therapy. Variables associated with increased probability of relapse were similar for first- and second-remission transplants and included GVHD prophylaxis without methotrexate and absence of GVHD. In first-remission transplants, leukocyte count greater than or equal to 50 x 10(9)/L at diagnosis was also associated with increased relapse; in second remission, relapse while receiving chemotherapy was also associated with increased posttransplant relapse. These data emphasize the importance of both disease- and transplant-related variables in predicting outcome after BMT. They may be used to explain differences between studies, design future trials, and identify persons most likely to benefit from BMT.

Adolescent↗
PubMed1989

The inexact use of Fisher's Exact Test in six major medical journals.

We reviewed the use of Fisher's Exact Test in 71 articles published between 1983 and 1987 in six medical journals. Thirty-three of 56 selected articles did not specify use of a one- or two-tailed test, and 12 (36%) of these actually used the one-tailed test. Five (42%) of these 12 articles contained at least one table in which the standard significance level of P less than .05 was no longer met when a two-tailed analysis was run instead. Eleven (65%) of 17 articles with a statistical consultant compared with 10 (28%) of 36 articles without a consultant specified use of a one- or two-sided test. The use of Fisher's Exact Test without specification as a one- or two-tailed version may misrepresent the statistical significance of data. A uniform specification statement should be required for all manuscripts to correct such potential errors in interpretation.

Periodicals as Topic↗