Biomedical subjects

N Lee

Publications and source records attributed to N Lee.

At least 127 records · Page 7Linked to original sources

PubMed1998

Complete heart block in association with graft-versus-host disease.

An infant who received haploidentical BM for severe combined immunodeficiency (SCID) developed acute, reversible complete heart block in association with an exacerbation of GVHD. Respiratory distress and myocardial dysfunction were also seen with this and previous GVHD exacerbations. The patient had not received chemotherapy or radiation prior to BMT. The complete heart block resolved after 1 week of intensive immunosuppression. The association of complete heart block with GVHD is important because the heart block is potentially reversible with prompt, aggressive control of the GVHD.

Bone Marrow Transplantation↗

PubMed1998

High-dose cyclophosphamide, etoposide and carboplatin with autologous bone marrow support for metastatic breast cancer: long-term results.

We report long-term results of high-dose cyclophosphamide, etoposide and carboplatin with ABMT in 20 patients with metastatic breast cancer. Median age of the group was 41 years, ECOG performance status = 0 in 18 patients and 1 in two patients. Twelve patients had received adjuvant chemotherapy. Predominant sites of metastases were lung (eight), chest wall (four), liver (four), bone (three) and lymph nodes (three). Response to pretransplant chemotherapy was complete (CR) in four patients, partial (PR) in 10 patients and stable (SD) in five patients. After high-dose chemotherapy eight patients were in CR, six PR, four SD and one progressive disease. Two patients died of regimen-related toxicities (candidal sepsis and alveolar hemorrhage). With a median follow-up period of 55 months (minimum 48 months), 12 patients have died of recurrent breast cancer, one died of toxicity of salvage chemotherapy, two are alive with disease, two are alive and free of progressive disease. One patient with relapsed disease was lost to follow-up. Median event-free survival is 6 months and median overall survival is 17 months. All three of the long-term disease-free survivors had predominantly nodal disease. Two of these three patients presented with metastatic disease and received high-dose chemotherapy with ABMT as part of initial therapy for breast cancer; two of three attained CR to standard-dose cytoreductive therapy; none received doxorubicin-containing adjuvant chemotherapy.

Adult↗

PubMed1998

Surgical outcome in patients with epilepsy with occult vascular malformations treated with lesionectomy.

PURPOSE: This retrospective study reports the long-term surgical outcome of patients with medically refractory epilepsy and vascular malformations who were treated with lesionectomy. A detailed analysis of surgical failures had been performed in an attempt to define predictors of surgical success and failure. METHODS: Fifteen patients with medically intractable epilepsy and angiographically occult vascular malformations (AOVMs) were treated surgically with lesionectomy at Duke University Medical Center. Lesionectomy consisted of removal of the AOVM and surrounding hemosiderin-stained brain only, without the use of electrocorticography (ECoG) to guide resection. RESULTS: Eleven (73%) patients are seizure free after lesionectomy. Three showed no significant improvement, and one patient died, presumably after a seizure. Age of onset, duration of seizures, age at resection, and gender did not affect outcome. All patients with neocortical AOVMs in whom EEG findings correlated with the site of the lesion were seizure free after lesional resection. Treatment failures were associated with the presence of multiple intracranial lesions, poorly localized or diffuse EEG findings, discordant positron emission tomography (PET) imaging, or with a lesion in close proximity to the limbic system. CONCLUSIONS: Lesionectomy, with removal of surrounding hemosiderin-stained brain, can be considered the procedure of choice in carefully selected patients with epilepsy with occult vascular malformations.

Adult↗

PubMed1998

The role of endothelin-1 in the aorta of post-infarct left ventricular dysfunction rats treated with captopril.

OBJECTIVES: There is little information available regarding local vasomotor regulating processes in chronic heart failure. In this study, we tested the hypothesis that chronic heart failure impaired the endothelial function, and long term captopril treatment might reverse endothelial activity through tissue endothelin (ET) pathway. METHODS: Forty Sprague-Dawley rats were divided into 4 groups including 15 rats in each of the sham-operated with or without captopril-treated groups and 5 rats in each of large infarcted with or without captopril-treated groups. RESULTS: Concentration-response curves obtained in aortic rings without endothelium revealed no difference in nitroprusside-induced relaxation. With endothelium, rightward shifting was noted only in the untreated large infarct group during acetylcholine-induced relaxation. As compared to the non-treated group, plasma ET-1 concentrations were lower in the captopril-treated with or without large infarct groups. However, endothelin-like immunoreactivity in endothelial cells and cytoplasma of smooth muscle cells of the media of the aorta were lower only in the non-treated large infarct group. CONCLUSIONS: Endothelial function was impaired in the chronic heart failure model. Coverting enzyme inhibitor might improve endothelial function through the Local endothelin pathway.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1998

Changes in the lipoprotein profile in postmenopausal women receiving hormone replacement therapy. Effects of natural and synthetic progesterone.

OBJECTIVE: To compare the effects of medroxyprogesterone acetate and micronized progesterone on the lipid profile of postmenopausal women receiving conjugated equine estrogen. STUDY DESIGN: A prospective, clinical study of the changes in lipoprotein profile evaluated in 123 postmenopausal women receiving conjugated estrogen alone (group I), conjugated estrogen combined with medroxyprogesterone acetate (group II) or micronized progesterone (group III) before treatment and six months after. RESULTS: Group I had significantly increased high-density lipoprotein cholesterol (HDL-C) levels (14.4%) after six months as well as decreased low-density lipoprotein cholesterol (LDL-C) concentrations (-6.61%), LDL/HDL and total cholesterol/HDL-C ratios (P < .05). In groups II and III, HDL-C concentrations increased 4.58% and 5.44%, respectively, after six months. LDL-C levels were markedly decreased in group II (8.98%). There was no significant reduction in LDL-C levels in group III. Total cholesterol levels were significantly decreased only in group II (-4.93%). Triglyceride levels were increased with statistical significance only in group III (21.2%, P < .05). LDL/HDL and total cholesterol/ HDL-C ratios were significantly decreased in group II, and this effect was more pronounced in group I. There was no change in the ratios in group III. CONCLUSION: Conjugated estrogen replacement therapy had a persistent cardioprotective effect in postmenopausal women, based on the positive effect on lipoprotein metabolism. Both natural and synthetic progesterones blunt the beneficial effects of estrogen on the lipoprotein profile, and micronized progesterone is not superior to medroxyprogesterone acetate.

Adult↗

PubMed1998

Cat-scratch disease caused by Bartonella henselae: the first case report in Taiwan.

We report a typical case of cat-scratch disease caused by Bartonella henselae, in Taiwan. A 20-year-old man developed right axillary lymphadenopathy 2 weeks after being scratched on his right hand by a kitten. The axillary lymphadenopathy resolved gradually and spontaneously after 10 weeks without specific treatment. Serologic tests were not done during the acute stage of the event. However, an immunofluorescent antibody test performed during the convalescent stage was positive for B. henselae antibodies, and the concentration dropped by fourfold 2 months later. Histopathologic examination of a biopsy specimen from the right axillary lymph node revealed findings characteristic of cat-scratch disease including multiple foci of microabscesses surrounded by histiocytes and infiltration by plasma cells and lymphocytes. This is the first reported case of cat-scratch disease in Taiwan, with a history of contact with a cat, a positive serologic test for B. henselae infection and characteristic histopathologic findings of cat-scratch disease which met the criteria for diagnosis.

Adult↗

PubMed1998

High-grade mucoepidermoid carcinoma of the breast: case report.

Mucoepidermoid carcinoma of the breast is very rare. Only 14 cases have been reported in the English language literature. All of these patients were women with ages ranging from 46 to 72 years. Five of the cases involved high-grade mucoepidermoid carcinomas and 9 were low-grade. All of the patients with low-grade mucoepidermoid carcinoma were disease-free in the follow-up period. Four patients with high-grade mucoepidermoid carcinoma died from the disease 7 to 30 months after surgery and all 4 were found to have distant metastasis. The case of mucoepidermoid carcinoma of the breast discussed here was histopathologically high-grade. The patient has remained disease-free 4 years after modified radical mastectomy and adjuvant chemotherapy. Diagnose of mucoepidermoid carcinoma of the breast is more difficult than mucoepidermoid carcinoma in the salivary gland due to possible confusion with metaplastic carcinoma or squamous cell carcinoma. Special histological stains are definitely needed for differential diagnosis.

Breast Neoplasms↗

PubMed1997

Activation of hPAK65 by caspase cleavage induces some of the morphological and biochemical changes of apoptosis.

Apoptosis is a highly regulated form of cell death, characterized by distinctive features such as cellular shrinkage and nuclear condensation. We demonstrate here that proteolytic activation of hPAK65, a p21-activated kinase, induces morphological changes and elicits apoptosis. hPAK65 is cleaved both in vitro and in vivo by caspases at a single site between the N-terminal regulatory p21-binding domain and the C-terminal kinase domain. The C-terminal cleavage product becomes activated, with a kinetic profile that parallels caspase activation during apoptosis. This C-terminal hPAK65 fragment also activates the c-Jun N-terminal kinase pathway in vivo. Microinjection or transfection of this truncated hPAK65 causes striking alterations in cellular and nuclear morphology, which subsequently promotes apoptosis in both CHO and Hela cells. Conversely, apoptosis is delayed in cells expressing a dominant-negative form of hPAK65. These findings provide a direct evidence that the activated form of hPAK65 generated by caspase cleavage is a proapoptotic effector that mediates morphological and biochemical changes seen in apoptosis.

Animals↗

PubMed1997

The complete genome sequence of the gastric pathogen Helicobacter pylori.

Helicobacter pylori, strain 26695, has a circular genome of 1,667,867 base pairs and 1,590 predicted coding sequences. Sequence analysis indicates that H. pylori has well-developed systems for motility, for scavenging iron, and for DNA restriction and modification. Many putative adhesins, lipoproteins and other outer membrane proteins were identified, underscoring the potential complexity of host-pathogen interaction. Based on the large number of sequence-related genes encoding outer membrane proteins and the presence of homopolymeric tracts and dinucleotide repeats in coding sequences, H. pylori, like several other mucosal pathogens, probably uses recombination and slipped-strand mispairing within repeats as mechanisms for antigenic variation and adaptive evolution. Consistent with its restricted niche, H. pylori has a few regulatory networks, and a limited metabolic repertoire and biosynthetic capacity. Its survival in acid conditions depends, in part, on its ability to establish a positive inside-membrane potential in low pH.

Antigenic Variation↗

PubMed1997

Immunohistochemical localization of netrin-1 in the embryonic chick nervous system.

Netrin-1 has profound in vitro effects on the growth properties of vertebrate embryonic axons. In addition, netrin-1 mRNA is found in the floor plate of the embryonic nervous system, an intermediate target of many axons, including commissural axons that are affected by netrin-1 in vitro. Moreover, genetic studies of netrin-1 homologs in Caenorhabditis elegans and Drosophila implicate these proteins in commissure formation. We raised polyclonal antisera that recognize chick netrin-1 in fixed tissue sections. The antisera were used to immunohistochemically map netrin-1 in the embryonic spinal cord, brain, and retina. The relationship between netrin-1 localization and the growth of pioneering axons suggests roles for netrin-1 in the regulation of circumferential, commissural, and longitudinal axon growth in the spinal cord and brain. The data also suggest that the primary or sole effect of netrin-1 on pioneering spinal cord commissural axons is haptotactic. Furthermore, the pattern of netrin-1 localization raises the possibility that this protein helps mediate neuronal migration in the spinal cord, brain, and retina.

Animals↗

PubMed1997

Effect of chelating agents and respiratory inhibitors on regulation of the cadA gene in Escherichia coli.

The cadA gene that encodes lysine decarboxylase in Escherichia coli is induced by low pH and - during anaerobic growth - by the substrate, lysine. We used operon fusions of cadA to lacZ to investigate the effects of aeration on cadA regulation. When an insertion mutation in osmZ (= hns) was introduced, a cadA-lacZ fusion was derepressed in the presence of air to approximately the same level as seen during anaerobic growth. However, the pH-dependent regulation of cadA was not affected by osmZ. Introduction of mutations in rpoS, fur, or fnr had no significant effect on cadA expression. However, defects in arcB or arcA largely abolished expression of cadA during anaerobic growth. Nonetheless, strains defective in both arcB and osmZ showed the same high cadA-lac expression in air as seen in the single osmZ derivatives. Blocking the respiratory chain with mutations or chemical inhibitors also caused derepression of a cadA-lacZ fusion in air, while agents affecting the proton gradient had no effect. Derepression of cadA in air was also mediated by several chelating agents, in particular by methoxyindole carboxylic acid. Addition of Fe2+ overcame this effect. Chelating agents also abolished the expression during aerobic growth of several genes known to be under arcAB control and which are normally repressed during anaerobic growth but induced in the presence of air. This implies that the effect of chelating agents on cadA expression is mediated via the arcAB regulatory system.

Aluminum Silicates↗

PubMed1997

Relevance of human papillomavirus screening in management of cervical intraepithelial neoplasia.

OBJECTIVE: To evaluate the utility of human papillomavirus detection in identifying women with abnormal Papanicolaou smears who can be safely followed up with cytologic study only, we conducted a study to determine the sensitivity, specificity, and negative and positive predictive values of a Food and Drug Administration-approved human papillomavirus test kit for detection of cervical intraepithelial neoplasia in colposcopically directed biopsy specimens. STUDY DESIGN: We enrolled women with abnormal Papanicolaou smears referred to a colposcopy clinic serving indigent patients. All 1128 women had a referral Papanicolaou smear, a clinic Papanicolaou smear, and a sample for human papillomavirus deoxyribonucleic acid test; 1075 underwent colposcopically directed biopsies and endocervical curettage. We used the HPV Profile kit for human papillomavirus testing. RESULTS: Of 486 women with low-grade squamous intraepithelial lesions on Papanicolaou smear, 35.4% had high-risk human papillomavirus deoxyribonucleic acid detected, and of 592 with high-grade lesions, 44.4% had high-risk human papillomavirus detected. Among 527 women with biopsy specimens showing cervical intraepithelial neoplasia and in 267 with cervical intraepithelial neoplasia grades 2 or 3, 38.7% and 56.2% had high-risk human papillomavirus deoxyribonucleic acid detected. However, the sensitivity of human papillomavirus deoxyribonucleic acid detection to identify biopsy-confirmed cervical intraepithelial neoplasia grades 2 or 3 was 55.7%, and the positive predictive value of the test was only 34.9%. CONCLUSION: Human papillomavirus appears to be causally associated with cervical cancer but human papillomavirus screening does not appear to be of value to identify women with abnormal Papanicolaou smears who can be safely followed up with cytologic study alone.

Adolescent↗

PubMed1997

Embryonic expression pattern of H218, a G-protein coupled receptor homolog, suggests roles in early mammalian nervous system development.

Heterologous expression studies employing mammalian cell tissue culture techniques and in vivo studies of lower eukaryotes suggest that G-protein coupled receptors may play critical roles in regulating early stages of vertebrate nervous system development. Previous work suggests that H218, a rat G-protein coupled receptor homolog, could serve such a role. Most importantly, northern blot data indicate that whole brain H218 mRNA levels are highest during embryogenesis. In the present studies we raised, affinity-purified and characterized several anti-H218, polyclonal antisera and immunohistochemically mapped the expression of H218 during the early stages of rat embryonic nervous system development. The resulting data indicate that H218 is preferentially expressed in young, differentiating neuronal cell bodies and axons. Moreover, the expression is temporally regulated such that highest H218 levels are found in neuronal cell bodies during their early stages of differentiation and in axons during their outgrowth. Therefore, we propose that H218 signal transduction may widely participate in the regulation of some of the first steps in neuronal differentiation including axon outgrowth.

Amino Acid Sequence↗

PubMed1997

Disseminated echovirus infection after allogeneic bone marrow transplantation.

Disseminated enteric human cytopathogenic orphan (echo) virus infection after allogeneic bone marrow transplantation has been reported once previously: a patient developed a fatal infection with the virus being isolated from brain, lung and heart. We report a second case of disseminated echovirus infection in which virus was isolated from the stomach and liver. On this occasion the infection was associated with the development of biopsy-proven acute graft-versus-host disease of the skin, stomach, colon and liver. The infection resolved without sequelae.

Biopsy↗

PubMed1997

Reconstruction of the immune system after unrelated or partially matched T-cell-depleted bone marrow transplantation in children: functional analyses of lymphocytes and correlation with immunophenotypic recovery following transplantation.

Reconstitution of the immune system following T-cell-depleted bone marrow transplantation (BMT) in children has yet to be fully elucidated. Thus, we prospectively studied the recovery of immune function in 64 children who underwent T-lymphocyte-depleted marrow transplants using either matched family member donors or matched unrelated donors. We measured in vitro posttransplantation proliferative responses to phytohemagglutinin (PHA), concanavalin A, pokeweed mitogen, and Candida albicans antigen and assessed unidirectional allogeneic mixed-lymphocyte culture (MLC) responses at various times. A total of 129 healthy individuals served as normal controls for these assays. Responses to T-cell mitogens normalized within 12 months posttransplantation, while MLC responses normalized by 9 months. The presence of graft-versus-host disease (grade II or greater) and cytomegalovirus infection was associated with delays in immune function recovery. Importantly, immune function recovery correlated temporally with a rise in peripheral lymphocyte count. In contrast, the CD4/CD8 ratio was not predictive of immune recovery. Knowledge of immune function recovery may guide clinicians in devising strategies to minimize the risk of infection post-BMT.

Adolescent↗

PubMed1997

Observations based upon multiple telephone contacts with new breastfeeding mothers.

Common themes and phenomena were identified by a lactation consultant providing an average number of nine follow-up phone contacts per mother during an average of 12 1/2 weeks postpartum. Over 600 mother-infant couples received lactation support services in the past 6 years. Eighty-six percent of the mothers receiving this telephone support breastfed for at least 1 month, 46% breastfed at least 3 months, and 23% breastfed for at least 5 months. Co-sleeping was encouraged in the first week postpartum, as was nursing one breast per feed. Normal breastfeeding was identified when the mothers nursed comfortably (save for first-minute latch-on pain), when they reported having fun with their babies, when their babies woke spontaneously to feed and to look around, when their babies urinated sufficiently and either had bowel movements or passed flatus, and when their babies were observed to smile. Anticipatory guidance about areolar engorgement, growth sports, and continuing to nurse despite maternal illness reduced bottle use in the first few weeks. The majority of women had no problems establishing breastfeeding with daily telephone contact for the first 5-7 days postpartum, one to three calls per week for the next few weeks, and gradually diminishing calls thereafter. Telephone calls were initiated by the LC, as only 12-16% of mothers called for help, even though they all received the LC's home telephone number.

Breast Feeding↗

PubMed1997

Clinical and electrographic manifestations of lesional neocortical temporal lobe epilepsy.

To determine whether lesional neocortical temporal lobe epilepsy (NTLE) can be differentiated from mesial temporal lobe epilepsy (MTLE) during the noninvasive presurgical evaluation, we compared the historical features, seizure symptomatology, and surface EEG of 8 patients seizure free after neocortical temporal resection with preservation of mesial structures and 20 patients after anterior temporal lobectomy for MTLE. Seizure symptomatology of 107 seizures (28 NTLE, 79 MTLE) was analyzed. One hundred one ictal EEGs (19 NTLE, 82 MTLE) were reviewed for activity at seizure onset; presence, distribution, and frequency of lateralized rhythmic activity (LRA); and distribution of postictal slowing. Seizure symptomatology and EEG data were compared between groups, and sensitivity, specificity, and positive and negative predictive values were determined for variables that differed significantly. Multiple logistic regression was used to determine whether patients could be correctly classified as having MTLE or NTLE. MTLE patients were younger at onset of habitual seizures and more likely to have a prior history of febrile seizures, CNS infection, perinatal complications, or head injury. NTLE seizures lacked features commonly exhibited in MTLE, including automatisms, contralateral dystonia, searching head movements, body shifting, hyperventilation, and postictal cough or sigh. NTLE ictal EEG recordings demonstrated lower mean frequency of LRA that frequently had a hemispheric distribution, whereas LRA in MTLE seizures was maximal over the ipsilateral temporal region. We conclude that it may be possible to differentiate lesional NTLE from MTLE on the basis of historical features, seizure symptomatology, and ictal surface EEG recordings. This may assist in the identification of patients with medically refractory nonlesional NTLE who frequently require intracranial monitoring and more extensive or tailored resections.

Adult↗

PubMed1997

Discovery of encysted Paragonimus westermani eggs in the omentum of an asymptomatic elderly woman.

We report a case of asymptomatic chronic infiltrate of the omentum by eggs of Paragonimus westermani in an elderly woman who had immigrated to Taiwan from mainland China 46 years ago. The patient had a habit of eating raw freshwater crabs from the lakes of eastern China during her period of residence in that country. She stopped eating raw crabs after coming to Taiwan 20 years ago. During surgery for a peptic ulcer complicated by severe bleeding in 1995, her omentum was found to contain many small nodules approximately 2 x 2 x 1.5 cm in size. Biopsy of the nodules revealed eggs of P. westermani embedded in necrotic debris surrounded by capsules. A sputum examination result was negative and a chest radiograph was normal. The majority of the nodules in the omentum were removed during the surgery and praziquantel was given. At the present time, the patient remains asymptomatic.

Aged↗