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Biomedical subjects

J Kang

Publications and source records attributed to J Kang.

At least 145 records · Page 8Linked to original sources
PubMed1998

Wallerian degeneration of the pyramidal tract does not affect stroke rehabilitation outcome.

OBJECTIVE: To test whether Wallerian degeneration (WD) of the pyramidal tract as signaled by MRI affects rehabilitation outcome in patients with subcortical infarction (internal capsule or corona radiata). BACKGROUND: Recent radiologic evidence suggests that WD occurs no earlier than 3 months after a subcortical infarction. METHODS: A total of 77 consecutive patients with pure motor hemiparesis due to an initial subcortical infarction were assessed on admission and discharge with the Functional Independence Measure (FIM) for disability and Stroke Impairment Assessment Set (SIAS, full = 25) for impairment. WD was defined by a high-intensity area detected along the pyramidal tract below the level of lesion on T2-weighted MR image (WD+). RESULTS: Age, sex, side of stroke, Mini-Mental State Examination score, and volume of lesion were comparable for each group. Length of stay (LOS) was significantly longer (p < 0.05) in WD+ (130 days) than in WD- (105 days). There was no difference in the change of FIM (WD+, 99 to 111; WD-, 95 to 107) or SIAS measures (WD+, 12 to 16; WD-, 13 to 16) made on admission and discharge, nor was there any effect of the timing of the rehabilitation experience (< or = 90 days or >90 days after stroke). CONCLUSIONS: After stroke, apparent WD of the pyramidal tract may slow functional recovery but does not limit final rehabilitation outcome of pure motor hemiparesis. Study of the mechanisms of compensation for this delayed pyramidal tract degeneration will enhance the scientific basis for rehabilitation.

Cerebral Infarction↗
PubMed1998

[Excess caloric intake induced severe hypercapnia in a patient with Duchenne muscular dystrophy on noninvansive positive pressure ventilation].

In many patients with neuromuscular diseases, respiratory failure is mainly caused by alveolar hypoventilation in their terminal stages. Malnutrition is one of the common and serious problems in patients with chronic respiratory failure. Energy consumption for breathing is remarkably high in respiratory compromised patients, causing subsequent increase of total energy expenditure. However, most patients have limited capacity of oral intake. Nutritional depletion is associated with wasting of respiratory muscles, impairment of respiratory drive, alteration of respiratory pattern, and pathological change of pulmonary parenchyma. These indicate that nutritional and ventilatory support is very important in these patients. However, overfeeding also may have detrimental influence on respiratory failure. We experienced a Duchenne muscular dystrophy (DMD) patient on noninvasive positive pressure ventilation (NIPPV) who developed hypercapnia after total parenteral nutrition (TPN). Analysis of clinical course of this patient revealed that there is a significant correlation between PaCO2 and caloric intake. Excess carbohydrate intake can precipitate fat synthesis which induces over-production of carbon dioxide (CO2). Since NIPPV doesn't have a closed circuit, there are some difficulties in respiratory management, such as air leakage to stomach and mouth, and airway obstruction. Failure to optimize NIPPV setting against increased CO2 load might cause hypercapnia in this patient. These suggest that evaluation of energy expenditure and design of nutritional program are essential to avoid hypercapnia due to nutritional support.

Adult↗
PubMed1998

[Generation and prediction of hypoxemia in patients with chronic obstructive pulmonary disease].

OBJECTIVE: To study the pathogenesis of nocturnal hypoxemia in patients with chronic obstructive pulmonary disease (COPD). METHOD: Daytime pulmonary functions, arterial blood gases and nocturnal oxygen level were measured in 30 patients and compared with those of 8 normal subjects. RESULTS: The nocturnal oxygen level significantly decreased in patients with COPD compared with that in normal subjects, especially during rapid eye movement (REM) period. The decreased extents of nocturnal mean oxyhemoglobin saturation (MSaO2) and nocturnal minimum oxyhemoglobin saturation (MmSaO2) were also very high in COPD (P < 0.05). From the distribution of oxyhemoglobin, the percentage of the time that oxyhemoglobin saturation (SaO2) < 80% and < 90% during sleep (T80, T90) in patients were found higher than those in normal subjects (P < 0.05). The sleep time in which SaO2 below 90 percent obviously increased in COPD patients. The correlative analysis indicated that daytime SaO2 and FEV1% were related to the nocturnal mean oxyhemoglobin saturation (r = 0.79, 0.54). So predictive formula of nocturnal oxyhemoglobin level was derived as follows: MSaO2(%) = 1.03 x SaO2(%) + 0.19 x FEV1%(%) - 14.35(r = 0.83). Daytime SaO2 and PaCO2 were also found concerned with nocturnal oxygen distribution: T80(%) = -2.64 x SaO2(%) + 6.98 x PaCO2(kPa) + 211.31(r = 0.78), T90(%) = -4.49 x SaO2(%) + 437.18(r = 0.62). CONCLUSION: It was observered that hypoxemia became worse in patients with COPD than in normal subjects during sleep. The level and the distribution of nocturnal oxygen could be predicted by daytime SaO2 and PaCO2. All these indicated that nocturnal oxygen therapy could be useful to improve the outcome of the COPD patients.

Aged↗
PubMed1998

[Relationship between lung function and nocturnal hypoxemia in patients with obstructive sleep apnea syndrome].

OBJECTIVE: To explore the relationship between the changes of lung function resulted from position changes and obesity, and nocturnal hypoxemia in patients with obstructive sleep apnea syndrome. METHOD: 34 patients with obstructive sleep apnea syndrome were detected by polysomnography with lung function and blood gas analysis in sitting and supine positions during wake, and the relationship between results of lung function and blood gas analysis, IBW% to the AI, and < 90% T (percentage of the duration of SaO2 below 90% to total sleep time) was analyzed. RESULT: The mean age of the patients was 44 +/- 13 years. The AI was 36 +/- 22 time.hour-1. On changing from sitting to supine position, PaO2, VC%, ERV, FRC, FRC%, RV%, TLC% decreased significantly, especially ERV and FRC%, which decreased 47% and 29% respectively. AI had positive correlation with VC% (r = 0.477, P < 0.01) and TLC% (r = 0.443, P < 0.01) in supine position, < 90% T had negative correlation with PaO2(r = -0.479, P < 0.01) and ERV (r = -0.416, P < 0.05) in sitting position. The IBW% had negative correlation with VC% in sitting (r = -0.547, P < 0.01) and supine position (r = -0.491, P < 0.01). IBW% also had negative correlation with ERV in sitting (r = -0.523, P < 0.01) and supine (r = -0.413, P < 0.01) position and FRC (r = -0.402, P < 0.05) in sitting position. The IBW% had positive correlation with the < 90% T(r = 0.514, P < 0.01). CONCLUSION: These results suggest that positional changes and obesity have effects on lung function in patients with OSAS, and lead to the deterioration of hypoxemia during apnea.

Adult↗
PubMed1998

[The occurrence of hypertension in patients with obstructive sleep apnea syndrome].

OBJECTIVE: To determine the changes in blood pressure (BP) and its correlated factors in patients with obstructive sleep apnea syndrome(OSAS). METHOD: Retaining manometric tube in radial artery and polysomnography(PSG) were done synchronously in 13 patients with OSAS in whom was diagnosed by whole-night PSG. Oxygen therapy was given to two of the patients and NCPAP treatment was given to four of the patients on the following night. RESULT: (1) Six of the patients (46 percent) had daytime hypertension (SBP > 18.7 kPa and/or DBP > 12 kPa), the incidence of transient hypertension during apnea in 7 patients who do not have daytime hypertension was 86% (6/7). (2) Lowest oxygen saturation during sleep was significantly correlated with the level of SBP(r = -0.659, P < 0.05) and DBP(r = -0.677, P < 0.01) in awake, the baseline of SBP(r = -0.777, P < 0.01) and DBP (r = -0.590, P < 0.05) in NREM sleep and that of SBP(r = -0.585, P < 0.05) in REM sleep. In REM sleep, the changes in MBP showed significantly correlation with the changes in oxygen saturation during apnea (r = 0.598, P < 0.05). In NREM sleep, the changes in SBP were significantly correlated with apnea length(r = 0.580, P < 0.05). The changes in BP showed no correlation with apnea index in different sleep stages (P > 0.05). (3) Nocturnal elevation in BP disappeared in four patients who received NCPAP treatment, but not in two patients who received oxygen therapy. CONCLUSION: The transient hypertension during apnea might be recurrent episodes in patients with OSAS who have normal daytime BP. Nocturnal hypoxemia and apnea length might play a role in nocturnal elevation in BP in patients with OSAS. Hypoxemia was not the major factor in BP elevation after obstructive apneas. Simple oxygen administration could not normalize the elevation in BP during apnea in patients with OSAS and NCPAP might be an appropriate therapy.

Adult↗
PubMed1998

[A study of lipid peroxide-induced damage and of ultrastructure of lens epithelial cells in lens organ culture in vitro].

OBJECTIVE: To understand the mechanism of the rabbit lens damage from lipid peroxidation (LPO) involved in cataract development. METHODS: Ultraviolet (UV) radiation was used to induce the damage of peroxidation on cultured rabbit lens. Cultured rabbit lenses were exposed to UV radiation in MEM cultural medium without or with superoxide dismutase (SOD) added at 10 U/ml. The thiobarbituric acid (TBA) colorimetric method was used to detect the lens malondialdehyde (MDA) content produced by LPO, and electron microscopy was used to observe the ultrastructure of rabbit lens epithelium. RESULTS: In the lens with UV radiation, MDA was increased as compared with that in non-irradiated one (P < 0.01) and in UV + SOD group (P < 0.01). The membranes of lens epithelial cells were damaged and mitochondria, etc. membranous structures disappeared with clumping pattern of chromatin, while the cells in UV + SOD and control groups appeared normal in structure. CONCLUSION: UV radiation can induce lipid peroxide damage in lens culture of rabbit.

Animals↗
PubMed1998

[A study on the binding of cyclodextrins with terbutaline enantiomers by chiral capilary zone electrophoresis].

The recognition mechanism of enantioselectivity in cyclodextrin-modified capillary zone electrophoresis (CD-CZE) on a racemic basic drug terbutaline was discussed. The equilibrium constants of host-guest complexation of terbutaline enantiomers with alpha-cyclodextrin, beta-cyclodextrin, 2,6-dimethyl-beta-cycoldextrin, 2,3,6-trimethyl-beta-cyclodextrin and 2-hydroxy-propyl-beta-cyclodextrin, and the thermodynamic parameters for chiral recognition procedure were determined respectively. It was found that the matching properties between cavity of cyclodextrins and enantiomers were interrelated with the equilibrium constants of binding complexes and selectivities(a) calculated from the ratio of binding constants of two enantiomers were in the same order of maximum electrophoretic mobility difference between two enantiomers responding with cyclodextrin additive. The experimental value of optimal concentration of cyclodextrin agreed with that calculated from the equation Copt = 1/(K1K2)1/2. From the thermodynamic parameter determination it was shown that the hydrogen-bonding interactions between terbutaline enantiomers and 2-hydroxy-propyl-beta-cyclodextrin and beta-cyclodextrin should be positive factors.

Cyclodextrins↗
PubMed1998

[Separation of human bladder cancer cells from bone marrow with a kind of immunomagnetic microspheres].

By binding a monoclonal antibody BDI-1 to polystyrene magnetic micospheres using physical and chemical methods together, a kind of immunomagnetic microspheres (IMMS), which can specifically bind target cells and give it magnetic response, was sucessfully constituted. The results of indirect immunofluorescence and cell binding suggest that IMMS can effectively bind target cells while do not have non-specific binding activity. The influence of antibody added and the ratio between IMMS and cells were also studied. After purging cancer cells from bone marrow of mice with IMMS, the cancer cells were effectively removed while most of the bone marrow cells were recovered.

Animals↗
PubMed1998

[A case of acute necrotizing encephalopathy of childhood with a good outcome].

We experienced a case of acute necrotizing encephalopathy of childhood with a good outcome. The disease continued for about three weeks, and the patient recovered with a sequela of mild left-hemiparesis. On the brain magnetic resonance imaging, abnormal intensity areas in the thalamus and putamen reduced size at an early stage of the disease. After 1 year, his mental and motor development seemed to be almost normal, but brain single photon emission computed tomography and electroencephalography were abnormal. Subclinical functional abnormalities persisted longer than had been expected.

Brain↗
PubMed1997

A novel gene, hKCa4, encodes the calcium-activated potassium channel in human T lymphocytes.

We have isolated a novel gene, hKCa4, encoding an intermediate conductance, calcium-activated potassium channel from a human lymph node library. The translated protein comprises 427 amino acids, has six transmembrane segments, S1-S6, and a pore motif between S5 and S6. hKCa4 shares 41-42% similarity at the amino acid level with three small conductance calcium-activated potassium channels cloned from brain. Northern blot analysis of primary human T lymphocytes reveals a 2.2-kilobase transcript that is highly up-regulated in activated compared with resting cells, concomitant with an increase in KCa current. hKCa4 transcript is also detected by Northern blots or by polymerase chain reaction in placenta, prostate, thymus, spleen, colon, and many cell lines of hematopoietic origin. Patch-clamp recordings of hKCa4-transfected HEK 293 cells reveal a large voltage-independent, inwardly rectifying potassium current that is blocked by externally applied tetraethylammonium (Kd = 30 +/- 7 mM), charybdotoxin (Kd = 10 +/- 1 nM), and clotrimazole (Kd = 387 +/- 34 nM), but is resistant to apamin, iberiotoxin, kaliotoxin, scyllatoxin (Kd > 1 microM), and margatoxin (Kd > 100 nM). Single hKCa4 channels have a conductance of 33 +/- 2 picosiemens in symmetrical potassium solutions. The channel is activated by intracellular calcium (Kd = 270 +/- 8 nM) with a highly cooperative interaction of approximately three calcium ions per channel. These properties of the cloned channel are very similar to those reported for the native KCa channel in activated human T lymphocytes, indicating that hKCa4 encodes this channel type.

Amino Acid Sequence↗
PubMed1997

Acceleration of a Diels-Alder reaction by a self-assembled molecular capsule.

The interior of cage-like molecules can be considered to provide a new phase of matter, in which it becomes possible to stabilize reactive intermediates and to observe new forms of stereoisomerism. Cage-like molecular complexes that self-assemble through weak intermolecular forces are dynamic species, encapsulating guest molecules reversibly. They can persist over timescales ranging from microseconds to hours, long enough for chemical processes to take place within them. Here we report the acceleration of a Diels-Alder reaction by encapsulation of the reactants in a self-assembling molecular capsule. Although product inhibition (lack of dissociation) prevents the system from showing true catalytic behaviour, there is clear evidence for a rate increase of over two orders of magnitude owing to the effective enhancement of concentration inside the capsule.

Chemistry, Organic↗
PubMed1997

Protein kinase C and receptor kinase gene expression in olfactory receptor neurons.

Recent biochemical evidence indicates that protein kinase C (PKC) and G-protein-coupled receptor kinases (GRKs) are involved in olfactory signal termination and desensitization. The polymerase chain reaction (PCR) was used to investigate the expression of PKC and GRK genes in olfactory tissue and in isolated olfactory receptor neurons from channel catfish (Ictalurus punctatus). Sequence analysis of cloned PKC PCR products showed that the alpha, beta, delta, epsilon, and theta isotypes were expressed in olfactory tissue. Sequence analysis of PCR products obtained from isolated olfactory receptor neurons showed that PKC beta and PKC delta were expressed in the receptor cells. A 600-bp GRK PCR product was obtained from isolated olfactory neurons that shared 86% and 92% amino acid sequence identity to the mammalian beta-adrenergic receptor kinase gene products beta ARK1 and beta ARK2, respectively. Go6976, a specific inhibitor of calcium-regulated PKC activity, completely inhibited odorant-stimulated PKC activity in isolated olfactory cilia. This result suggested that odorant-stimulated PKC activity is mediated by the calcium-sensitive PKC beta isotype. Taken together, these results are consistent with the conclusion that PKC beta and beta ARK mediate odorant receptor phosphorylation and olfactory signal termination.

Amino Acid Sequence↗
PubMed1997

Events that regulate differentiation of alpha beta TCR+ and gamma delta TCR+ T cells from a common precursor.

T cells in vertebrates are composed of two distinct lineages of cells distinguished by the type of antigen receptors they express: the conventional population expresses TCR composed of alpha beta heterodimers while a smaller fraction of mature T cells displays gamma delta TCRs on the cell surface. The alpha beta and gamma delta T cells develop from common T-cell progenitors and the alpha beta/gamma delta lineage commitment process should be viewed in the context of the diverse cell fate decision processes crucial for normal cell differentiation from a single pluiripotent stem cell. A major focus in this field has been to determine the role of TCR gene rearrangement and expression in alpha beta/gamma delta lineage commitment. In this review we summarize the current state of understanding in the pattern of TCR gene rearrangement and expression of alpha beta and gamma delta T cells to address this central question of whether or not the lineage commitment is dictated by the state of TCR gene rearrangement.

Animals↗
PubMed1997

Haloperidol, lorazepam, or both for psychotic agitation? A multicenter, prospective, double-blind, emergency department study.

Rapid tranquilization is a routinely practiced method of calming agitated psychotic patients by use of neuroleptics, benzodiazepines, or both in combination. Although several studies have examined the efficacy of the three approaches, none have compared these treatments in a prospective, randomized, double-blind, multicenter trial. Ninety-eight psychotic, agitated, and aggressive patients (73 men and 25 women) were prospectively enrolled during an 18-month period in emergency departments in five university or general hospitals. Patients were randomly assigned to receive intramuscular injections of lorazepam (2 mg), haloperidol (5 mg), or both in combination. Patients in each treatment group received 1 to 6 injections of the same study drug within 12 hours, based on clinical need. They were evaluated hourly after the first injection until at least 12 hours after the last. Efficacy was assessed on the Agitated Behavior Scale (ABS), a modified Brief Psychiatric Rating Scale (MBPRS), Clinical Global impressions (CGI) scale, and an Alertness Scale. Effective symptom reduction was achieved in each treatment group with significant (P < .01) mean decreases from baseline at every hourly ABS evaluation. Significant (P < .05) mean differences on the ABS (hour 1) and MBPRS (hours 2 and 3) suggest that tranquilization was most rapid in patients receiving the combination treatment. Study event incidence (side effects) did not differ significantly between treatment groups, although patients receiving haloperidol alone tended to have more extrapyramidal system symptoms. The superior results produced by the combination treatment support the use of lorazepam plus haloperidol as the treatment of choice for acute psychotic agitation.

Adolescent↗
PubMed1997

Metabolic efficiency during arm and leg exercise at the same relative intensities.

This study was conducted to compare gross efficiency (GE), net efficiency (NE), work efficiency (WE), and delta efficiency (DE) between arm crank and cycle exercise at the same relative intensities. Eight college-aged males underwent two experimental trials presented in a randomized counterbalanced order. During each trial subjects performed three intermittent 7-min exercise bouts separated by 10-min rest intervals on an arm or semirecumbent leg ergometer. The power outputs for the three bouts of arm crank or cycle exercise corresponded to 50, 60, and 70% of the mode-specific VO2peak. GE, NE, and WE were determined as the ratio of Kcal.min-1 equivalent of power output to Kcal.min-1 of total energy expended, energy expended above rest and energy expended above unloaded exercise, respectively. DE was determined as the ratio of the increment of Kcal.min-1 of power output above the previous lower intensity to the increment of kcal.min-1 of total energy expended above the previous lower intensity. GE and NE did not differ between arm crank and cycle exercises. However, WE was lower (P < 0.05) during arm crank than cycle exercise at 50, 60, and 70% VO2peak. DE was also lower (P < 0.05) during arm crank than cycle exercise at delta 50-60 and at delta 60-70% VO2peak. It is concluded metabolic efficiency as determined by work and delta efficiency indices was lower during arm crank compared with cycle exercise at the same relative intensities. These findings add to the understanding of the difference in metabolic efficiency between upper and lower body exercise.

Adult↗
PubMed1997

Acute effect of amino acid ingestion and resistance exercise on plasma growth hormone concentration in young men.

Sixteen men completed four trials at random as follows: (Trial A) performance of a single bout of resistance exercise preceded by placebo ingestion (vitamin C); (Trial B) ingestion of 1,500 mg L-arginine and 1,500 mg L-lysine, immediately followed by exercise as in Trial A; (Trial C) ingestion of amino acids as in Trial B and no exercise; (Trial D) placebo ingestion and no exercise. Growth hormone (GH) concentrations were higher at 30, 60, and 90 min during the exercise trials (A and B) compared with the resting trials (C and D) (p < .05). No differences were noted in [GH] between the exercise trials. [GH] was significantly elevated during resting conditions 60 min after amino acid ingestion compared with the placebo trial. It was concluded that ingestion of 1,500 mg arginine and 1,500 mg lysine immediately before resistance exercise does not alter exercise-induced changes in [GH] in young men. However, when the same amino acid mixture is ingested under basal conditions, the acute secretion of GH is increased.

Adult↗