Biomedical subjects

M Lee

Publications and source records attributed to M Lee.

At least 271 records · Page 15Linked to original sources

PubMed2000

Histology and tetracycline labeling of a single section of alveolar bone of first molars in the rat.

We observed the histology and tetracycline (TC) labeling in a single frontal section of alveolar bone of upper first molars of adolescent rats. A single injection of TC was administered intraperitonealy in adolescent rats. After three weeks, the upper jaws were immersed rapidly in liquid nitrogen and sectioned. Five micrometer unfixed, undecalcified frozen sections were cut and observed by light and fluorescence microscopy. Frontal sections of the upper first molar area revealed that the structural relationships among the roots, the periodontal ligament and the alveolar bone, and also between the cervical enamel and the attachment epithelium were well preserved. The TC labeling lines in the sections were very clear and distinguished new bone from old bone. The brightness of the lines differed among regions. An analysis of the brightness in the same section suggested a difference in the bone forming activity at the time of injection.

Alveolar Process↗

PubMed2000

Surgical treatment of intractable epilepsy accompanying cortical dysplasia.

OBJECT: Surgical treatment of cortical dysplasia (CD) together with intractable seizures is challenging because both visualization and localization of the lesion are difficult, correlation with seizure foci requires comprehensive study, and the surgical outcomes reported thus far are unsatisfactory. The authors report their experience in the surgical treatment of CD classified according to a surgical point of view. METHODS: The definition of CD used in this study was a dysplastic lesion visible on magnetic resonance (MR) images or a lesion that, although not visible on MR images, was diagnosed as moderate-to-severe dysplasia by using pathological analysis. During the last 4.5 years, the authors treated 36 patients with intractable epilepsy accompanied by CD. They divided the 36 cases of CD into four characteristic groups: Group A, diffuse bilateral hemispheric dysplasia; Group B, diffuse lobar dysplasia; Group C, focal dysplasia; and Group D, a moderate to severe degree of CD with a normal appearance on MR images. All but one patient in Group C were monitored in the epilepsy monitoring unit by using subdural electrodes for seizure localization and functional mapping. The incidence of CD among a cohort of 291 patients who had undergone epilepsy surgery at the authors' center during the study period was 12.4%. The mean age of the 36 patients was 21.3 years and the mean age at seizure onset was 8.5 years. The mean follow-up period was 26 months. Twenty-six patients (72.2%) belonged to Engel Class I or II (20 and six, respectively). There were five cases in Group A, nine in Group B, nine in Group C, and 13 in Group D. Patients in Groups A and B were significantly younger at seizure onset and had significantly poorer surgical outcomes compared with patients in Groups C and D (p < 0.05). If outcome is compared on the basis of the extent of removal of CD, patients in whom CD was completely removed had significantly better outcomes than those in whom CD was only partially removed (p < 0.001). CONCLUSIONS: The authors conclude that intractable epilepsy accompanied by CD can be treated surgically using comprehensive preoperative approaches. Deliberate resective procedures aimed at complete removal of dysplastic tissue ensure excellent seizure control without permanent neurological deficit.

Adolescent↗

PubMed2000

Defects in the differentiation and function of bone marrow-derived dendritic cells in non-obese diabetic mice.

Due to their high immunostimulatory ability as well as the critical role they play in the maintenance of self-tolerance, dendritic cells have been implicated in the pathogenesis of autoimmune diseases. The non-obese diabetic (NOD) mouse is an animal model of autoimmune type 1 diabetes, in which pancreatic beta cells are selectively destroyed mainly by T cell-mediated immune responses. To elucidate initiation mechanisms of beta cell-specific autoimmunity, we attempted to generate bone marrow-derived dendritic cells from NOD mice. However, our results showed low proliferative response of NOD bone marrow cells and some defects in the differentiation into the myeloid dendritic cells. NOD dendritic cells showed lower expressions of MHC class II, B7-1, B7-2 and CD40, compared with C57BL/6 dendritic cells. In mixed lymphocyte reactions, stimulatory activities of NOD dendritic cells were also weak. Treatment with LPS, INF-gamma and anti-CD40 stimulated NOD dendritic cells to produce IL-12p70. The amount of IL-12, however, appeared to be lower than that of C57BL/6. Results of the present study indicated that there may be some defects in the development of NOD dendritic cells in the bone marrow, which might have an impact on the breakdown of self tolerance.

Animals↗

PubMed2000

Expression of progesterone receptor in human keratinocytes.

Despite the various responses of human skin to female sex hormones, cellular and subcellular targets and the mechanisms of action of estrogen and progesterone in human skin are not well understood. The detection of estrogen receptor (ER) and progesterone receptor (PR) in the skin is of great importance to understand the effect of estrogen and progesterone. In primary cultures of human keratinocytes, expression of ER and PR was monitored by immunocytochemistry and reverse transcriptase polymerase chain reaction (RT-PCR). Paraffin embedded skin tissues were stained with monoclonal antibodies to human ER and PR by immunohistochemistry. Cultured human keratinocytes expressed cytoplasmic PR protein and PR mRNA transcripts. By contrast, ER was detected only at the mRNA level. Suprabasal keratinocytes from samples of pruritic urticarial papules, plaques of pregnancy (PUPPP) and psoriasis were stained positively only for PR, while those from samples of erythema nodosum were negative for both ER and PR. Lesional epidermis of PUPPP showed positive PR immunoreactivity, while nonlesional epidermis did not. No other cells in the normal human skin were stained with ER and PR. The present study suggests that by expressing PR human keratinocytes act as targets for progesterone action.

Adolescent↗

PubMed2000

Changes in gallbladder motility in gastrectomized patients.

OBJECTIVES: Gastric resection may predispose gallstone formation. However, the mechanism has not been clearly understood. To evaluate the relationship between gastric resection and gallstone formation, we compared gallbladder(GB) motility in gastrectomized patients and control subjects. METHODS: We compared the GB volume and ejection fraction of the 46 gastrectomized patients with 37 healthy controls using real time ultrasonography. RESULTS: GB volume increased significantly in the gastrectomized group in fasting (30.2 +/- 13.9 ml). The GB volume after a fatty meal was greater in the gastrectomized group (12.6 +/- 6.4 ml) than in the control group (4.3 +/- 3.3 ml) (p < 0.01). A significant reduction of ejection fraction was found in gastrectomized patients (56.9 +/- 13.0%) in comparison with the control group (75.5 +/- 16.1%) (p < 0.01). The GB ejection fraction had a poor correlation to the postoperative period (r = 0.232). CONCLUSION: A gastrectomy appears to be a risk factor of GB dysmotility, which may play a major role in gallstone formation in gastrectomized patients.

Adult↗

PubMed2000

Polymicrobial cholangitis and liver abscess in a patient with the acquired immunodeficiency syndrome.

Cholangitis/cholangiopathy associated with the human immunodeficiency virus (HIV) infection is characterized by chronic abdominal pain, low-grade fever, cholestasis, and sometimes areas of focal or diffuse dilatation of the bile ducts that may be apparent on noninvasive imaging studies. Although the etiology of this biliary disease may be multifactorial, it appears to be the result of immunosuppression and/or secondary opportunistic infections rather than a direct cytopathic effect of HIV itself. Various opportunistic pathogens, including cytomegalovirus, Cryptosporidium, Campylobacter fetus, and Candida albicans, have been implicated as causes of HIV-associated cholangitis. We report an unusual case of polymicrobial cholangitis and liver abscess in a patient with HIV infection.

AIDS-Related Opportunistic Infections↗

PubMed2000

Massive upper gastrointestinal hemorrhage due to cytomegalovirus infection in two patients with acquired immunodeficiency syndrome.

Massive upper gastrointestinal (GI) hemorrhage is a rare manifestation of GI cytomegalovirus (CMV) infection. A review of the English language literature yielded 21 well-documented cases of gastric ulcers due to CMV, and 7 of these 21 cases were complicated by significant GI bleeding. This report describes two cases of massive upper GI hemorrhage due to CMV infection in patients with acquired immunodeficiency syndrome (AIDS).

AIDS-Related Opportunistic Infections↗

PubMed2000

Female gamete segregation in two carriers of translocations involving 2q and 14q.

FISH, using a combination of whole-chromosome painting and telomeric probes, was used to study the gamete segregation of two female carriers of translocations involving the same chromosome arms, 2q and 14q. Preimplantation genetic diagnosis of the first polar bodies of these oocytes permitted selecting normal embryos for replacement.

Abortion, Spontaneous↗

PubMed2000

Are nonspecific practice guidelines potentially harmful? A randomized comparison of the effect of nonspecific versus specific guidelines on physician decision making.

OBJECTIVE: To test the ability of two different clinical practice guideline formats to influence physician ordering of electrodiagnostic tests in low back pain. DATA SOURCES/STUDY DESIGN: Randomized controlled trial of the effect of practice guidelines on self-reported physician test ordering behavior in response to a series of 12 clinical vignettes. Data came from a national random sample of 900 U.S. neurologists, physical medicine physicians, and general internists. INTERVENTION: Two different versions of a practice guideline for the use of electrodiagnostic tests (EDT) were developed by the U.S. Agency for Health Care Policy and Research Low Back Problems Panel. The two guidelines were similar in content but varied in the specificity of their recommendations. DATA COLLECTION: The proportion of clinical vignettes for which EDTs were ordered for appropriate and inappropriate clinical indications in each of three physician groups were randomly assigned to receive vignettes alone, vignettes plus the nonspecific version of the guideline, or vignettes plus the specific version of the guideline. PRINCIPAL FINDINGS: The response rate to the survey was 71 percent. The proportion of appropriate vignettes for which EDTs were ordered averaged 77 percent for the no guideline group, 71 percent for the nonspecific guideline group, and 79 percent for the specific guideline group (p = .002). The corresponding values for the number of EDTs ordered for inappropriate vignettes were 32 percent, 32 percent, and 26 percent, respectively (p = .08). Pairwise comparisons showed that physicians receiving the nonspecific guidelines ordered fewer EDTs for appropriate clinical vignettes than did physicians receiving no guidelines (p = .02). Furthermore, compared to physicians receiving nonspecific guidelines, physicians receiving specific guidelines ordered significantly more EDTs for appropriate vignettes (p = .0007) and significantly fewer EDTs for inappropriate vignettes (p = .04). CONCLUSIONS: The clarity and clinical applicability of a guideline may be important attributes that contribute to the effects of practice guidelines.

Decision Making↗

PubMed2000

A safer plasma supply from remunerated donors--"The Immuno/Community Bio-Resources experiment".

With the goal of increasing the safety of plasma used in the manufacture of therapeutic products, Immuno and its subsidiary Community Bio-Resources (now a division of Baxter Healthcare Corporation), have developed a comprehensive plasma quality programme. This programme includes four main safety initiatives: a plasma centre location/appearance programme, a Qualified Donor programme, an Inventory Hold, and the PCR testing of plasma pools. Many of these initiatives have been adopted in part by the plasma collection and fractionation industry. Using a statistical model that takes into consideration the unique donation characteristics of remunerated plasma donors, combined with 1998 CBR virus reactive rates, an estimated residual likelihood of an undetected donation entering a plasma pool was determined. These estimates, for each million donations, were 0, 1.64, and 4.68 donations for HIV, HBV, and HCV, respectively, and were far below those previously reported for remunerated or volunteer donations. These estimates were confirmed by subsequent PCR testing, which allowed for the additional removal of positive units before manufacture. The low virus load of this plasma supply, combined with increasingly effective virus removal and inactivation procedures, has resulted in the safest ever supply of plasma derivatives.

Biological Products↗

PubMed2000

The motor cortex shows adaptive functional changes to brain injury from multiple sclerosis.

Although multiple sclerosis (MS) is an inflammatory demyelinating disease, there can be substantial axonal injury and loss. We therefore hypothesized that adaptive cortical changes may contribute to limiting functional impairment, particularly in the early stages of the disease. To test our hypothesis, we used functional magnetic resonance imaging (MRI) to characterize the localization and volumes of activation in the motor cortex during simple flexion-extension finger movements. There were differences in the patterns of cortical activation with movement between the 12 MS patients and the 12 normal controls. All patients showed greater relative supplementary motor area activation than did the normal controls. The relative hemispheric lateralization of sensorimotor cortex (SMC) activation decreased in direct proportion to the total cerebral T2-weighted MRI hyperintense lesion load. This appeared to be due primarily to increases in ipsilateral SMC activation with increasing lesion load in white matter of the hemisphere contralateral to the limb moved. The center of activation in the contralateral SMC was shifted a mean of 8.8 mm posterior in patients relative to controls, providing additional evidence for cortical adaptive responses to injury. The magnitude of this posterior shift in the SMC activation increased with greater T2 lesion loads. These observations demonstrate that cortical recruitment for simple finger movements can change both quantitatively and qualitatively in the SMCs of MS patients, suggesting that cortical reorganization or "unmasking" of latent pathways can contribute to functional recovery. These adaptive changes are another factor potentially limiting the strength of the relationship between MRI measures of pathology and clinical measures of disability.

Adaptation, Physiological↗

PubMed2000

Direct and indirect costs associated with the onset of seropositive rheumatoid arthritis. Western Consortium of Practicing Rheumatologists.

OBJECTIVE: To examine the direct and indirect costs of rheumatoid arthritis (RA) during the first year of disease. METHODS: As part of a longitudinal observational study, 150 patients with seropositive RA of 5.9 +/- 2.9 mo duration were recruited through the Western Consortium of Practicing Rheumatologists. Subjects completed questionnaires about health care services and resources utilized and about the number of days of usual activity lost as a result of RA during the 6 month period prior to enrolment. RESULTS: Study participants had active RA as evidenced by mean tender and swollen joint counts of 24.9 +/- 13.5 and 20.6 +/- 11.6, respectively, and moderate functional impairment reflected by a mean Health Assessment Questionnaire (HAQ) score of 1.24 +/- 0.7. The average total direct cost of RA was $200/month. Health care visits, medications, and radiographs accounted for 78% of the total direct cost, while expenditures for hospitalizations accounted for only 3.5% of the total. The average number of days of usual activity lost per month because of RA was 3.8 +/- 7.7, translating into an average indirect cost of $281/month. Of the 95 subjects who were gainfully employed prior to disease onset, 12 were disabled and 5 were on sick leave as a result of RA, corresponding to a work disability rate of 18%. Work disabled subjects reported significantly lower total household incomes and higher HAQ disability and global disease activity scores than subjects who continued working. CONCLUSION: In this group of patients with seropositive RA substantial costs, both direct and indirect, were incurred during the first year of disease.

Arthritis, Rheumatoid↗

PubMed2000

Identification of domains in apoA-I susceptible to proteolysis by mast cell chymase. Implications for HDL function.

When stimulated, rat serosal mast cells degranulate and secrete a cytoplasmic neutral protease, chymase. We studied the fragmentation of apolipoprotein (apo) A-I during proteolysis of HDL(3) by chymase, and examined how chymase-dependent proteolysis interfered with the binding of eight murine monoclonal antibodies (Mabs) against functional domains of apoA-I. Size exclusion chromatography of HDL(3) revealed that proteolysis for up to 24 h did not alter the integrity of the alpha-migrating HDL, whereas a minor peak containing particles of smaller size with prebeta mobility disappeared after as little as 15 min of incubation. At the same time, generation of a large (26 kDa) polypeptide containing the N-terminus of apoA-I was detected. This large fragment and other medium-sized fragments of apoA-I produced after prolonged treatment with chymase were found to be associated with the alphaHDL; meanwhile, small lipid-free peptides were rapidly produced. Incubation of HDL(3) with chymase inhibited binding of Mab A-I-9 (specific for prebeta(1)HDL) most rapidly (within 15 min) of the eight studied Mabs. This rapid loss of binding was paralleled by a similar reduction in the ability of HDL(3) to induce high-affinity efflux of cholesterol from macrophage foam cells, indicating that proteolysis had destroyed an epitope that is critical for this function. In sharp contrast, prolonged degradation of HDL(3) by chymase failed to reduce the ability of HDL(3) to activate LCAT, even though it led to modification of three epitopes in the central region of apoA-I that are involved in lecithin cholesterol acyltransferase (LCAT) activation. This differential sensitivity of the two key functions of HDL(3) to the proteolytic action of mast cell chymase is compatible with the notion that, in reverse cholesterol transport, intactness of apoA-I is essential for prebeta(1)HDL to promote the high-affinity efflux of cellular cholesterol, but not for the alpha-migrating HDL particles to activate LCAT.

Animals↗

PubMed2000

Short-term effects of lumbar posteroanterior mobilization in individuals with low-back pain.

OBJECTIVE: To establish the short-term effects of lumbar posteroanterior mobilization in patients with low-back pain, compared with a control intervention. DESIGN: Self-controlled cross-over design. MAIN OUTCOME MEASURES: The force-displacement characteristics of the spine in response to the application of a posteroanterior force, lumbar flexion, and extension range of movement; pain during flexion, extension, and on worst movement; pain on posteroanterior loading; and overall pain relief. PATIENTS: Twenty-six patients with nonspecific low-back pain who experienced pain on flexion or extension and whose pain settled quickly after provocation, from a physiotherapy clinic and university campus. METHODS: Patients received posteroanterior mobilization and a control intervention in an order that was randomly allocated. The magnitude of force in treatment dose was selected by the treating physiotherapist. An observer who was blinded to the order of interventions performed all measurements. Outcome measures were recorded before and after each intervention, and change scores were calculated to quantify the effect of the intervention. RESULTS: No significant differences were found between the mobilization and control interventions in relation to posteroanterior response or range of movement. The score for pain on worst movement showed significantly greater improvement for the mobilization than for the control procedure. CONCLUSIONS: Lumbar posteroanterior mobilization was not observed to produce any objectively measurable change in the mechanical behavior of the lumbar spine of patients with low-back pain. Improvement in some pain variables was observed in comparison with a control procedure, but this may be due to a placebo effect.

Adolescent↗

PubMed2000

Radicicol suppresses expression of inducible nitric-oxide synthase by blocking p38 kinase and nuclear factor-kappaB/Rel in lipopolysaccharide-stimulated macrophages.

We show that radicicol, a fungal antibiotic, produces a marked inhibition of p38 kinase, nuclear factor-kappaB/Rel (NF-kappaB/Rel), and inducible nitric-oxide synthase (iNOS) transcription by the macrophage line RAW 264.7 in response to lipopolysaccharide (LPS). Treatment of RAW 264.7 with radicicol inhibited LPS-stimulated p38 kinase phosphorylation in a dose-related manner. iNOS transcription, which is regulated in part by the NF-kappaB/Rel family of transcription factors, has been shown to be under the control of the p38 kinase signaling cascade. Our data also show that the p38 kinase pathway is specifically involved in LPS-induced NF-kappaB/Rel activation and iNOS expression because NF-kappaB/Rel DNA binding and iNOS mRNA production in the presence of a specific inhibitor of p38 kinase, SB203580, were dramatically diminished. In contrast, PD98059, a specific inhibitor of mitogen-activated protein kinase/extracellular signal-regulated protein kinase kinase 1 had no effect on NF-kappaB/Rel activation and iNOS expression. LPS-induced loss of inhibitory proteins IkappaB-alpha and IkappaB-beta and translocation of p65, c-Rel, and p50 was inhibited by radicicol. Collectively, this series of experiments indicates that radicicol inhibits iNOS gene expression by blocking p38 kinase signaling. Due to the critical role that NO release plays in mediating inflammatory responses, the inhibitory effects of radicicol on iNOS suggest that this potent antifungal agent may represent a useful anti-inflammatory agent.

Animals↗

PubMed2000

Platelet surface P-selectin molecules increased after exposing platelet to a high shear flow.

BACKGROUND: P-selectin is known to play a crucial role in leucocyte recruitment at sites of vascular injury. Although platelet surface expression of P-selectin molecules are well known to occur after platelet stimulation by chemical agonists such as alpha-thrombin, it is still uncertain whether P-selectin expression occurs in the process of the more physiological platelet activation pathway mediated by interaction between von Willebrand factor (vWF) and platelet receptor proteins, including glycoprotein (GP) Ibalpha and GP IIb/IIIa, occurring under high shear rates generated by blood flow. METHODS: We have developed a method to detect P-selectin molecules expressed on platelet surface with flow-cytometer and monoclonal antibody, which can bind exclusively to P-selectin (WGA1), directly conjugated with fluorescein isothiocynate. This method allowed us to measure platelet surface P-selectin molecules semiquantitatively. RESULTS: We demonstrated that a significant increase in platelet surface P-selectin molecules occur after exposing platelets to a relatively high shear rate of 10,800 s(-1). We have also demonstrated that shear-induced surface expression of P-selectin as well as microparticle release from platelets depended at least on the interaction between von Willebrand factor and glycoprotein Ibalpha, a platelet surface receptor for the former. CONCLUSIONS: Shear-induced von Willebrand-mediated surface expression of P-selectin may play a role in leucocyte recruitment in platelet thrombi at vascular injury sites.

Antibodies, Monoclonal↗

PubMed2000

Current awareness

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of prenatal diagnosis. Each bibliography is divided into 17 sections: 1 Books, Reviews & Symposia; 2 General Interest; 3 Normal Fetal Development; 4 Gametogenesis and Pre-implantation Diagnosis; 5 First Trimester Diagnosis; 6 Second Trimester Diagnosis; 7 Fetal Diagnosis by Ultrasound and Other Imaging; 8 Maternal Screening; 9 Screening for Carriers of Genetic Abnormality; 10 Technological Developments; 11 Confined Placental Mosaicism and Uniparental Disomy; 12 Molecular Cytogenetics; 13 Fetal Cells in Maternal Circulation; 14 Fetal Therapy; 15 Psychosocial Aspects; 16 Epidemiology and Environmental Factors; 17 Developmental Pathology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted

Journal Article↗

PubMed2000

Utilization of parenteral nutrition in patients receiving peripheral blood stem cell transplantation.

A paucity of information is available on the use of parenteral nutrition (PN) in patients undergoing peripheral blood stem cell transplantation (PBSCT). To characterize the utilization of PN in patients undergoing PBSCT, we conducted a retrospective chart review study on adult patients receiving autologous and allogeneic PBSCT. Data collection included nutritional parameters such as indications for PN, days of PN administration, and PN-associated complications (i.e., metabolic, infectious, and mechanical). Outcome parameters assessed included length of hospitalization, days to engraftment, graft versus host disease (GVHD), and veno-occlusive disease (VOD). A total of twenty-one consecutive patients were evaluated with 12 receiving allogeneic PBSCT and 9 receiving autologous PBSCT. The allogeneic group received PN for a mean of 25 days compared to 21 days for the autologous group. The rate of metabolic abnormalities was significantly higher in the allogeneic group compared to the autologous group (1.02 abnormalities/PN days vs 0.61 abnormalities/PN day, p < 0.05), but mechanical and infectious complications were similar between the two groups. Length of hospitalization, days to engraftment, incidence of GVHD and VOD did not differ significantly between the two groups. However, mortality prior to discharge was significantly higher in the allogeneic vs autologous group (58% vs 0%, p < 0.05). We conclude that allogeneic PBSCT patients appear to be at a greater risk for metabolic complications while receiving PN as compared to autologous PBSCT patients. As nausea and vomiting are two primary reasons for initiation of PN in this patient population, further studies of aggressive antiemetic therapy may prove to decrease the need for PN in PBSCT patients.

Adult↗