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Biomedical subjects

M C Lee

Publications and source records attributed to M C Lee.

At least 163 records · Page 9Linked to original sources
PubMed1998

Evidence that Calu-3 human airway cells secrete bicarbonate.

The Calu-3 cell line is being investigated as a model for human submucosal gland serous cells. In a previous investigation of basal short-circuit current (Isc) in Calu-3 cells, high levels of bumetanide-insensitive basal Isc (approximately 60 microA/cm2) were measured in cells grown at an air interface. Basal Isc was reduced only 7% by bumetanide, and the largest component of basal Isc required both Cl- and HCO3- in the bathing solutions. Because Isc could be partially inhibited by basolateral 4,4'-dinitrostilbene-2,2'-disulfonic acid and because the only known apical exit pathway for anions is the cystic fibrosis transmembrane conductance regulator, which has a relatively poor conductance for HCO3-, it was concluded that most basal Isc is HCO3(-)-dependent Cl- secretion [M. Singh, M. Krouse, S. Moon, and J. J. Wine. Am. J. Physiol. 272 (Lung Cell. Mol. Physiol. 16): L690-L698, 1997]. We have now measured isotopic fluxes of 36Cl- and 22Na+ across short-circuited Calu-3 cells and found that virtually none of the basal Isc is Cl- secretion or Na+ absorption. Thus, in contrast to the earlier report, we conclude that the major component of basal Isc is HCO3- secretion. Stimulation recruits primarily Cl- secretion, as previously proposed.

Bicarbonates↗
PubMed1998

Micrographia after thalamo-mesencephalic infarction: evidence of striatal dopaminergic hypofunction.

A patient with left thalamo-mesencephalic infarction presented with micrographia in the right hand as the only motor sign. Brain MRI and 99mTc ethyl cysteinate dimer (ECD) perfusion SPECT revealed ischemic lesions in the left midbrain and the anterior thalamus, but not in the basal ganglia, whereas [123I]-IPT SPECT demonstrated decreased activity of the [123I]-IPT in the left striatum. The patient's micrographia may be related to a dysfunctional nigrostriatal dopaminergic system secondary to ischemic damage to the substantia nigra.

Cerebral Infarction↗
PubMed1998

Ultrastructure of neuromuscular junction in vacor-induced diabetic rats.

OBJECTIVES: Rodenticide Vacor causes a severe peripheral neuropathy in humans. Electrophysiologic studies on a peripheral motor nerve-skeletal system of Vacor-treated rat showed decreased amplitude of muscle action potential without conduction velocity abnormalities. The ultrastructural studies of the neuromuscular junction were performed to clarify the anatomic site of the Vacor-induced peripheral neuropathy in male Wistar rats. METHODS: After oral administration of a single dose of Vacor, 80 mg/kg of body weight, to the experimental animals, neuromuscular junctions within the interosseous muscles of the hind foot were observed in time. RESULTS: No axon terminal change was noted until 24 hours after the administration of Vacor. Remarkable loss of presynaptic vesicles and swollen endoplasmic reticulum in the axon terminal were developed at 3 days after Vacor treatment. Progressive degenerative changes consisting of marked loss of presynaptic vesicles, focal disruption of membrane in the axon terminal with disappearance of the number of the damaged axon terminal appeared, and flattening of postsynaptic folds was also seen. CONCLUSIONS: These results suggest that degenerative changes in axon terminal at neuromuscular junction may contribute to the peripheral neuropathy developed in the early phase of Vacor poisoning.

Animals↗
PubMed1998

Factors related to adolescents' perceptions of treatment outcomes in an adolescent health clinic.

To determine factors related to adolescents' perceived treatment outcomes of their health problems in an adolescent health clinic located at a college hospital, 246 adolescent patients between the ages of 11 and 21 who visited the clinic twice or more during the period January 1994 to December 1995 were included in this study. Information concerning adolescents' sociodemographic characteristics, family function, office visits and health problems of first visits was collected by reviewing subjects' medical and other clinic-related records. In addition, a structured questionnaire was mailed to assess subjects' satisfaction with physicians and the environment and services provided by the clinic as well as their perceived treatment outcomes. 148 patients completed the questionnaire, a response rate of 60.2%. Most of the respondents were in late-stage adolescence (71.0%) and were in school (71.0%). About half of respondents had normal family function, while the other half had moderate or severe family dysfunction. Most of the health problems of respondents were acute (64.2%) and were biological (76.4%) conditions. Most of the respondents were satisfied with the various characteristics of physicians except confidentiality emphasized by the physicians, while many fewer respondents were satisfied with the environment and services provided by the clinic. Family function, physicians' respect toward the adolescents, and the adolescents' satisfaction with the services provided in general were the factors significantly related to adolescents' perceived treatment outcomes based on a stepwise, multiple logistic regression analysis. We conclude that efforts to provided could result in better adolescent perceived treatment outcomes.

Adolescent↗
PubMed1998

Patient's perception of pain: comparison between Korean-American and Euro-American obstetric patients.

This study explored the differences and similarities in the perception of pain reported between Korean-American and Euro-American obstetric patients, describing whether the different ethnocultural background of patients affected their perception of pain. Gate control theory provided the basis for the study. The theory of pain emphasizes the role of psychological variables in the perception of pain and behavioral responses to pain. The sample (N = 124) consisted of 67 Euro-American and 57 Korean-American patients, who had delivered a baby within 12 to 24 hours of the interview in a large community hospital in New York City. The results indicated that there were statistically significant differences in the quality of pain especially in affective type of pain experience and overall evaluation of pain while no significant differences appeared in the pain intensity in general between the two groups. Also, there were many interesting findings such as using own words in expressing pain, preferences in gender of baby, and childbirth training, or social support which reflected much cultural influences.

Adult↗
PubMed1998

Elimination of hypercapnia may postpone the clinical presentation of malignant hyperthermia: a case report.

Malignant hyperthermia is a rare complication in clinical anesthesia, especially associated with the administration of succinylcholine or inhalation anesthetics. A 19-year-old patient, suffering from traumatic mandible fracture, underwent open reduction under general anesthesia. Unfortunately, following administration of succinylcholine, he also suffered severe facial twitch and the first episode of hypercapnia. After adequate management, the symptoms subsided. However, two hours later, the hypercapnia recurred, combined with progressive elevation of body temperature. After administration of intravenous dantrolene 120 mg, the patient's condition became stable and the procedure was completed without sequelae. As the muscle contracture test is not available in Taiwan, the clinical grading scale is presented as an alternative diagnostic method for malignant hyperthermia.

Adult↗
PubMed1997

Neuronal differentiation of human neuroblastoma SH-SY5Y cells by gangliosides.

Exogenous administration of gangliosides induced neuronal differentiation with prominent neuritogenesis in human neuroblastoma SH-SY5Y cells in vitro. Neuritogenesis was characterized by ruffling of the cell membrane, the development of lamellipodia and filopodia, and the subsequent elongation and branching of the neurites ultrastructurally. Both axons and neurites were identified. Increased numbers of cell organelles in the neurites and cell bodies were noted. Nonsynaptic contacts and gap junctions formed between neurites or between each neurite and cell body. These findings could be implicated in histopathologic changes from neuroblastoma to ganglioneuroblastoma.

Cell Differentiation↗
PubMed1997

Cytogenetic abnormalities related to histopathologic grade of astrocytic tumors.

Cytogenetic analysis was performed on 7 low-grade astrocytomas, 10 anaplastic astrocytomas, and 14 glioblastomas. Abnormal chromosome numbers were noted in all cases of high-grade astrocytomas but were rarely noted in low-grade astrocytomas (28%). The most consistent changes in high-grade astrocytomas were complete loss of chromosome 10 (61%), gain of chromosome 7 (56%), and loss of chromosome 17 (28%). Certain structural abnormalities, such as marker chromosomes and double minutes (33%), and the deletion and translocation of chromosomes 1 (33%) and 17 (17%), were also noted. These results indicate that changes in the number and/or structure of chromosomes with related inactivation of tumor suppressor gene or oncogene activation might play a critical role in the formation and anaplastic progression of astrocytic tumors.

Adolescent↗
PubMed1997

Total parenteral nutrition alters NPY/PYY receptor levels in the rat brain.

The regulation of appetite and satiety is complex and may involve peptide mediators such as cholecystokinin (CCK) and neuropeptide Y (NPY). Studies have indicated that calories administered enterally and parenterally impact on feeding, and possibly via the release of such mediators. Recent data from our laboratory have shown that total parenteral nutrition (TPN) reduces sham feeding in dogs by 50%. We hypothesized that TPN may alter feeding via an NPY-mediated mechanism. To test our hypothesis, we examined the effect of continuous administration of TPN on NPY receptor levels in the rat brain. Rats were surgically prepared with intravenous catheters. After 72 h of TPN infusion, the rats were anesthesized with sodium pentobarbital and their brains were removed. Neuropeptide Y receptor density was assessed by autoradiography in the paraventricular nucleus, olfactory cortex, dentate gyrus, and thalamus. These results were compared to the control group receiving intravenous saline. A third group receiving enteral nutrition was examined as well. Neuropeptide Y receptor numbers were significantly increased in the paraventricular nucleus of rats receiving TPN compared to the groups receiving intravenous saline or enteral nutrition. We conclude that continuous parenteral nutrition significantly increases NPY receptor density in the rat brain suggesting that TPN may impact feeding via the regulation of NPY receptor-mediated effects.

Animals↗
PubMed1997

In vitro and in vivo properties of murine monoclonal antibody for a novel immature thymocyte-differentiated antigen, JL1.

JL1 is a novel thymocyte-differentiated antigen strictly confined to stage II immature cortical thymocytes. It is expressed in several types of leukemias and lymphomas. Murine anti-JL1 monoclonal antibody labeled with 131I and 99mTc showed 60-70% of immunoreactivity and 1.4-1.9 x 10(9) L/mol of affinity constant. The incubation of the radiolabeled antibody with Molt-4 cells showed no evidence of modulation or shedding. Localization indices increased from day 3 to day 5 in SCID mice bearing Molt-4 cells.

Animals↗
PubMed1997

Balo's concentric sclerosis: a clinical case study of brain MRI, biopsy, and proton magnetic resonance spectroscopic findings.

The antemortem diagnosis of Balo's concentric sclerosis was made in a 52 year old woman with subacute right hemiparesis on the basis of brain MRI and stereotactic brain biopsy, which showed multiple ring-like lesions of lamellated demyelination alternating with spared white matter. Proton magnetic resonance spectroscopy (1H-MRS) was carried out one and nine months after the onset of illness. The first 1H-MRS showed a decreased N-acetyl aspartate peak, an increased choline peak, presence of large lipid peaks, and high resonance at 1.4 ppm. The second 1H-MRS disclosed changes such as a decrease of lipid signal, a decrease of resonance at 1.4 ppm, and an increase in the myoinositol peak. These findings are similar to those reported for multiple sclerosis. It seems that this is the first report of 1H-MRS findings in Balo's concentric sclerosis.

Biopsy, Needle↗
PubMed1997

Patterns of sensory dysfunction in lateral medullary infarction. Clinical-MRI correlation.

Sensory dysfunction in lateral medullary infarction (LMI) has been insufficiently studied. We prospectively analyzed the sensory signs of 50 consecutive patients with LMI, correlating them with MRI results. The classical ipsilateral trigeminal-contralateral body/limb pattern was observed only in 13 patients (26%) with lesions confined to the most posterolateral part of the caudal-middle medulla, whereas the bilateral trigeminal pattern observed in 12 patients was associated with large, ventrally extending lesions usually at the middle-rostral medulla. The contralateral trigeminal pattern was observed in nine patients with lesions sparing the most posterolateral area of the medulla. Isolated body/limb and isolated trigeminal involvement were observed in 10 and four patients respectively, usually associated with very small lesions. No sensory sign was noted in two patients. In addition to impaired sensation of spinothalamic modalities, six patients had decreased vibratory sensation in the hypoalgesic body/limb, whereas four patients had a lemniscal sensory deficit on the side contralateral to the hypoalgesic body/limb. Fifteen patients showed sensory gradient or level at the body/limb, and five had delayed appearance of sensory deficits. Trigeminal sensation was usually inhomogeneously involved among three divisions, which was more often of an onion-skin pattern than a divisional pattern. The perioral area, or V3, was generally spared or less severely involved on the side contralateral to the lesion. The sensory manifestations of LMI are extremely diverse and usually, although not always, correlate with MRI findings. The so-called classic, dissociated sensory pattern is actually uncommon, whereas sensory patterns previously thought of as atypical are relatively frequent.

Adult↗
PubMed1997

A case of carpal tunnel syndrome due to dialysis-related amyloidosis in a patient undergoing long-term hemodialysis.

Carpal tunnel syndrome (CTS) is characterized by burning pain, numbness and tingling sensation in the thumb, index and middle fingers and the lateral half of the palm and progressive atrophy of the thenar muscles by compression of the median nerve within the carpal tunnel due to a variety of etiologic factors. Surgical intervention usually successfully relieves symptoms of CTS. Recently CTS has been regarded as one of the major clinical manifestations of dialysis-related amyloidosis due to beta 2-microglobulin deposition and recognized with increasing frequency in patients undergoing long-term hemodialysis. We report a case of carpal tunnel syndrome due to dialysis-related amyloidosis in patients undergoing long-term hemodialysis, confirmed by electromyography and biopsy in transverse carpal ligament and median nerve.

Amyloid Neuropathies↗
PubMed1997

Display of coregistered cross-modality images using time-weighted alternation method.

Cross-modality coregistration of functional and anatomical images has rapidly grown as the aid for the interpretation of functional images. Various methods have been previously investigated so that the coregistered images can be easily interpreted and realistically visualized. We used the time/intensity-weighted alternation method to display the coregistered images simultaneously. Stereotactic registration was done with two methods. We realized the automated method of alignment using the boundary of head scalp extracted from the sinogram of a PET emission scan and surface-matching algorithm in brain, and the semi-automated method using a paired point-matching algorithm in the chest and abdomen. For the simultaneous display of the stereotactically registered images, rapid switching of the screens were applied on which both images were written with independent color scales. Rapid alternate display of two images, that is synchronized using the monitor scanning process, could induce the fusion of images in the human visual perception system. Also, intensification of an interesting image is possible by weighting the displaying time or global intensities of images with the degree of interest. These techniques could be useful for the interpretation and visualization of the coregistered images.

Brain↗
PubMed1997

Crossed-cerebellar diaschisis in cerebral infarction: technetium-99m-HMPAO SPECT and MRI.

UNLABELLED: We studied 26 patients with a single supratentorial infarction using 99mTc-HMPAO SPECT and MRI to investigate the phenomenon of crossed-cerebellar diaschisis (CCD). METHODS: From the total single-photon emission counts obtained from each cerebellar hemisphere, the percent difference between the contralateral (CCH) and ipsilateral (ICH) cerebellar hemispheres [delta %cbll = (CCH-ICH)/ ICH x 100] was calculated. Both SPECT (SVD) and MRI volume deficit (MVD) were measured to examine their relationship with CCD. RESULTS: A CCD was observed in 12 of the 26 patients (46%) with cerebral infarction. There was no significant correlation between SVD and delta %cbll or MVD and delta %cbll in the patients with cerebral infarction. There were no significant differences in SVD and MVD between the patients with and without CCD. The frequency of CCD was significantly higher in the patients whose infarctions were in the frontoparietal lobes or the deep middle cerebral artery territory, including the basal ganglia and internal capsule (11/19) than in the patients whose infarctions were in other regions (1/7) (p = 0.048). The severely hemiparetic patients had a higher frequency of CCD and lower delta %cbll than the patients with milder or no hemiparesis (frequency, 5/5 compared with 6/18, p = 0.008; delta %cbll, -21.4% +/- 3.8% compared with -8.3% +/- 11.1%, p = 0.018). However, CCD also occurred in 5 of the 14 patients without hemiparesis and was not seen in 5 of the 12 hemiparetic patients. None of the patients with CCD demonstrated the apparent clinical signs of cerebellar dysfunction. CONCLUSION: The location rather than the extent and severity of the lesion may be the major determinant for the occurrence and magnitude of CCD in patients with cerebral infarction. Our results also support the notion that CCD is a consequence of the interruption of the corticopontocerebellar pathway at the supratentorial level.

Adult↗