PubMed Health⌕ Search

Biomedical subjects

M Kang

Publications and source records attributed to M Kang.

At least 19 recordsLinked to original sources

Ectopic expression of serotonin-positive neurons in the hypothalamus associated with a significant serotonin decrease in the midbrain of food restricted rats.

The effects of food restriction on the serotonergic system were investigated immunohistochemically in both the midbrain and hypothalamic regions of rats. Rats were fed on a restricted feeding schedule consisting of half of the ad libitum quantity for 1, 2, 4 and 6 weeks and a free feeding schedule for 1 week. The optical density of serotonin-positive neurons in the raphe nuclei of the midbrain was found to be significantly lower in the 1 week-food restricted group than in the ad libitum fed control. In the hypothalamus, serotonin-positive neurons were observed in the 1 and 2 week food restricted groups but not in the 4 and 6 week-food restricted groups. This finding was confirmed by immunohistochemistry with tryptophan hydroxylase, a serotonin synthesizing enzyme. In this study, we provide morphological evidence that food restriction has a significant effect on the serotonergic system of the midbrain and hypothalamic regions and suggest some possibilities for the ectopic expression of serotonin-positive neurons after food restriction.

Animals↗

Electroacupuncture-related changes of NADPH-diaphorase and neuronal nitric oxide synthase in the brainstem of spontaneously hypertensive rats.

The aim of this study was to investigate the electroacupuncture-related changes of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) and neuronal nitric oxide synthase (nNOS) in the brainstem of spontaneously hypertensive rats (SHR). We evaluated the changes of NADPH-d-positive neurons using a histochemical method and the changes of nNOS-positive neurons using an immunohistochemical method. The staining intensities of NADPH-d-positive neurons and nNOS-positive neurons were assessed in a quantitative fashion using a microdensitometrical method based on optical density by means of an image analyzer. The optical density of NADPH-d-positive neurons and nNOS-positive neurons of the Shinsu (BL23) and Choksamni (ST36) electroacupuncture groups were significantly decreased in most brainstem areas as compared to the normal and arbitrary groups, with the exception of the optical density of NADPH-d positive neurons in the prepositus nucleus as compared to the arbitrary group. The present results demonstrated that electroacupuncture changes the activity in the NO system in the brainstem of SHR and the site where electroacupuncture is administered is of importance for this effect.

Animals↗

Human immunodeficiency virus type 1 (HIV-1) gp120-specific antibodies in neonates receiving an HIV-1 recombinant gp120 vaccine.

Infants born to human immunodeficiency virus type 1 (HIV-1)-infected mothers were immunized at birth and at ages 4, 12, and 20 weeks with low-, medium-, or high-dose recombinant gp120 vaccine with MF59 adjuvant (HIV-1(SF-2); n=52) or with MF59 alone as a placebo (n=9). An accelerated schedule (birth and ages 2, 8, and 20 weeks) was used for an additional 10 infants receiving the defined optimal dose and for 3 infants receiving placebo. At 24 weeks, anti-gp120 ELISA titers were greater for vaccine-immunized than for placebo-immunized infants on both schedules, and 87% of vaccinees had a vaccine-induced antibody response. At 12 weeks, antibody titers of infants on the accelerated vaccine schedule exceeded those of infants receiving placebo (4949 vs. 551; P=.01), and 63% of the vaccinees met the response criteria. Thus, an accelerated schedule of gp120 vaccinations generated an antibody response to HIV-1 envelope distinct from transplacental maternal antibody by age 12 weeks. These results provide support for further studies of vaccine strategies to prevent mother-to-infant HIV-1 transmission.

AIDS Vaccines↗

A Phase I study of infusional vinblastine in combination with the P-glycoprotein antagonist PSC 833 (valspodar).

BACKGROUND: PSC 833 is a second-generation P-glycoprotein (Pgp) antagonist developed to reverse multidrug resistance (MDR). The authors conducted a Phase I study of orally administered PSC 833 in combination with vinblastine administered as a 5-day continuous infusion. METHODS: Seventy-nine patients with advanced malignant disease were enrolled in the trial and treated with escalating doses of PSC 833. Pharmacokinetic interactions between PSC 833 and vinblastine were anticipated. Accordingly, when dose limiting toxicities were observed, the dose of vinblastine was reduced as PSC 833 was escalated. Three schedules and two formulations of PSC 833 were used in the study. RESULTS: The maximum tolerated doses of PSC 833 were 12.5 mg/kg orally every 12 hours for 8 days for the liquid formulation in combination with 0.9 mg/m(2) per day vinblastine as a continuous intravenous infusion (CIV) for 5 days; and 4 mg/kg orally every 6 hours for 8 days for the microemulsion formulation in combination with 0.6 mg/m(2) per day vinblastine CIV for 5 days. The principal toxicities for PSC 833 were ataxia and paresthesias and for the combination, constipation, fever. and neutropenia. Increased oral bioavailability and increased peak and trough concentrations were observed with the microemulsion formulation. Significant interpatient variability in pharmacokinetic parameters was observed. Ten patients studied at the MTD for PSC 833 (4 mg/kg orally every 6 hours for 8 days) had inhibition of rhodamine efflux from CD56 positive peripheral lymphocytes as a surrogate for Pgp antagonism. Among 43 evaluable patients with clear cell carcinoma of the kidney, 3 patients had complete responses, and 1 patient had a partial response. CONCLUSIONS: PSC 833 in combination with vinblastine can be administered safely to patients provided the vinblastine dose is adjusted for pharmacokinetic interactions. The high interpatient variability is a significant confounding factor. Surrogate studies with CD56 positive cells suggest that Pgp inhibition in the clinical setting is achievable. Improved methods for predicting pharmacokinetic interactions should improve future studies.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Inhibition of neuronal nitric oxide synthase enhances cell proliferation in the dentate gyrus of the adrenalectomized rat.

Recent studies have demonstrated that the elimination of adrenal steroids by an adrenalectomy (ADX) increases the expression of neuronal nitric oxide synthase (NOS), and that it increases cell proliferation in the rat dentate gyrus. However, no evidence has been presented to date which indicates that NO regulates cell proliferation in the dentate gyrus of the adult rats. In this study, the effect of blocking NO production on ADX-induced increase of cell proliferation and serotonergic innervation was examined in the rat dentate gyrus. 7-nitroindazole (7-NI; 30 mg/kg, intraperitoneally), a selective inhibitor of neuronal NOS, was injected 1 day before an ADX and then once every 24 h for 4 days after the ADX subsequently. The proliferating cells were identified with 5-bromo-2-deoxyuridine (BrdU) immunostaining. Long-term inhibition of the neuronal NOS by 7-NI markedly increased the BrdU-labeled cell population density 4-18-fold in the dentate gyrus of the adrenalectomized rats compared to that in the vehicle-injected adrenalectomized rats. Immunoreactivity of serotonin, known as a mediator of granule cell genesis, was detected only in the dentate gyrus of 7-NI-injected adrenalectomized rats. These results indicate that NO may be involved in the cell proliferation in the dentate gyrus of the adrenalecomized rat and that serotonin may mediate the regulatory effect of NO on the cell proliferation in rat dentate gyrus.

Adrenal Cortex↗

Atomic size effects in continuum modeling.

Continuum modeling of many physical systems typically assumes that the spatial extent of an atom is small compared to the quantities of interest and can therefore be neglected. We show that this is valid only asymptotically. For many applications of practical interest, the spatial extent of a discrete atom cannot be neglected. We have developed a model for the description of epitaxial growth based on the levelset method, and find that we can accurately predict quantities such as the island densities, if we implement boundary conditions in a region with atomic width, rather than just on a line without any spatial extent. Only in the limit of very large islands and island spacings can this be neglected.

Journal Article↗

Nd1, a novel murine Kelch family protein, may play the role of a housekeeping gene.

The murine Nd1 gene encodes a novel Kelch family protein and expresses two forms of mRNA, long (Nd1-L) and short (Nd1-S), in various tissues. We characterized the genomic organization of the Nd1 gene, and found that Nd1-L and Nd1-S consist of 16 and nine exons respectively, and that exons I-VIII are shared between them. Three transcription initiation sites were identified in the 5'-flanking region and the most 3' side (+1) is likely to be a major one. Promoter analysis revealed that the region between positions -247 and -86 was sufficient for expression, and that two Sp1-binding sites and one NF-kappaB-binding site in the region were critical for promoter activity. Furthermore, the promoter region lacks a TATA and a CAAT box and has a highly GC-rich region with two important Sp1-binding sites. These characteristics of the Nd1 gene promoter are similar to the properties of housekeeping genes.

Amino Acid Sequence↗

Observation of multiple magnetorotons in the fractional quantum Hall effect.

Magnetorotons in the dispersions of collective gap excitation modes of fractional quantum Hall liquids are measured in resonant inelastic light scattering experiments. Two deep magnetoroton minima are observed at nu = 2/5, while a single deep minimum is resolved at nu = 1/3. The observations are the first evidence of multiple roton minima in gap excitations of the quantum liquids. The results support Chern-Simons and composite fermion calculations that predict multiple roton minima for states with nu>1/3.

Journal Article↗

Safety of 2 recombinant human immunodeficiency virus type 1 (HIV-1) envelope vaccines in neonates born to HIV-1-infected women.

To determine the safety of 2 candidate vaccines against human immunodeficiency virus type 1 (HIV-1), a randomized, placebo-controlled, multicenter trial compared low, medium, and high doses of the vaccines or an adjuvant among infants born to HIV-infected women. No local or systemic reactions of grade 2 or greater were reported 48 h after the subjects underwent immunization. Grade 3 or 4 chemistry toxicities occurred in 5 (3%) and grade 3 or 4 hematologic toxicities in 17 (11%) of 154 vaccinated subjects (not significantly different from 29 adjuvant recipients). CD4(+) cell percentages of < or = 20% occurred at least once in 9 vaccinated subjects and 1 control subject. Sustained CD4(+) cell percentages of < or = 20% occurred in 4 HIV-infected children. Fourteen infants (8%) were confirmed to be HIV-infected; median CD4(+) cell counts among these children were 2074, 1674, 1584, and 821 cells/mm(3) at birth and weeks 24, 52, and 104, respectively. Thus, both vaccines were safe and well tolerated in neonates, and there was no evidence of accelerated immunologic decline in HIV-infected infants.

AIDS Vaccines↗

Differential changes in neuropeptide Y and nicotinamide adenine dinucleotide phosphate-diaphorase-positive neurons in rat hippocampus after kainic acid-induced seizure.

Changes in neuropeptide Y (NPY) and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d)-positive neurons in the hippocampus were investigated 5, 10 and 20 days after kainic acid (KA) administration using a double labeling method. The numbers of NADPH-d-positive-only and NPY/NADPH-d-positive neurons decreased in the CA1/2-CA3 regions of the hippocampus, 5, 10 and 20 days after KA administration, however, the number of NPY-positive-only neurons increased in the same regions 5 and 10 days after KA administration. In the dentate gyrus (DG) region of the hippocampus, the numbers of NPY-positive-only, NADPH-d-positive-only and NPY/NADPH-d-positive neurons increased 5 days after KA administration, and 20 days after KA administration, the number of NADPH-d-positive-only neurons decreased to levels similar to or lower than the level of the controls. However, the numbers of NPY/NADPH-d-positive and NPY-positive-only neurons in the DG region 20 days after KA administration remained at control levels. These results indicate that, NADPH-d-positive-only neurons are vulnerable to, and NPY-positive-only neurons are resistant to KA-induced seizures in the whole hippocampus, but that NPY/NADPH-d-positive neurons have different sensitivities in subregions of the hippocampus to KA-induced seizures. In addition, the present findings provide the first statistical and morphological evidence, which demonstrates that NPY-positive-only, NADPH-d-positive-only and NPY/NADPH-d-positive neurons in the hippocampus have different sensitivities to KA-induced seizures.

Animals↗

The effects of regular source of care and health need on medical care use among rural adolescents.

OBJECTIVE: To examine those factors associated with the use of different types of ambulatory health services in a rural adolescent population. METHODS: The student bodies of 2 middle schools and 2 high schools in rural areas in a mid Atlantic state (N = 1615) were surveyed using a self-administered health status and health services use instrument. Logistic regression was used to assess factors predicting receipt of (1) preventive services, (2) problem-focused services, and (3) emergency services. RESULTS: One third of the rural youth reported having received preventive services within the previous 3 months; 41% received problem-focused care, and 18% received emergency services. Having the same provider for both preventive and illness care was the most consistent and significant predictor of receipt for all types of ambulatory services. Of special note is the greater use of emergency services when subjects did not have a consistent provider for both preventive and illness care. Health need variables, measured across a wide range of domains, were additionally predictive, and their significance varied according to the type of services received. CONCLUSIONS: This study provides compelling evidence that for rural adolescents, having a regular source of care and medical need are the most important predictors of use across a variety of types of ambulatory care.

Adolescent↗

Myocardial protection of immature rabbits with an ATP-sensitive K+ channel opener pinacidil.

OBJECTIVE: To investigate the effectiveness of pinacidil, an opener of ATP-sensitive K+ channels, in protecting the myocardium of immature rabbit hearts from ischemic reperfusion injury. METHODS: Rabbit hearts underwent 30 min of global normothermic ischemia followed by 30 min of reperfusion on the modified Langendorff apparatus. Fifty-two isolated hearts of 3-4 week-old immature rabbits were divided into 4 groups randomly. During ischemia, 3 different cardioplegic solutions were administered intermittently by infusion every 15 min (20-25 ml each time in all groups). Group 1: control group (n = 13); group 2: Krebs-Henseleit (K-H) solution with potassium (16 mmol/L) (n = 13); group 3: K-H solution with potassium (16 mmol/L) and pinacidil (50 mumol/L) (n = 13); group 4: K-H solution with potassium (16 mmol/L), pinacidil (50 mumol/L) and glibenclamide (10 mumol/L) (n = 13). The pre-ischemic and post-ischemic myocardial functions were assessed by the percentage recovery of the left ventricular developed pressure (LVDP); the left ventricular end-diastolic pressure (LVEDP); both the positive peak and negative peaks of the first derivative of the left ventricular pressures (+/- dp/dtmax); coronary flow; the level of creatine kinase (CK), lactic dehydrogenase (LDH) and aspartate transcarbamoylase (AST) in coronary sinus venous effluent; and by myocardial ultrastructural changes. RESULTS: Before myocardial ischemia, there were no significant differences among the four groups in any of the parameters mentioned above. Post-ischemic recovery of LVDP, LVEDP, +/- dp/dtmax, coronary flow, the level of CK, LDH and AST, and myocardial ultrastructural changes were better in group 3 than those in the three other groups. CONCLUSIONS: As a new and effective composition, pinacidil can significantly improve myocardial protection from cardioplegia for immature rabbit hearts.

Animals↗

[Treatment of pleural effusion caused by lung carcinoma with circular intrapleural hyperthermic perfusion and its mechanism].

OBJECTIVE: To assess the comprehensive effectiveness of intrapleural hyperthermic perfusion in treatment of malignant pleural effusion (MPE) caused by lung carcinoma and to explore its nechanism. METHODS: 45 patients with MPE caused by lung carcinoma underwent circular intrapleural hyperthermic perfusion with 43 warmed normal saline for 60 minutes. Response of pleural effusion and the original lung tumor, sife-effects, life qualty and survival time of the patients were followed up. Flow cytometry, optical microscopy, electron microscopy, and TUNEL method were used to compare the cytology and biochemistry of pleural effusion and cancer cells planted to the surface of pleura before and after the therapy. RESULTS: The control rate of pleural effusion was 100% (CR 93.3%, PR 6.7%). No recurrence of pleural effusion was observed in 44 cases. Pleural effusion reoccured 12 months after the thermotherapy in one case. The time without pleural effusion lasted 16.5 months on average with the longest time of 40 months. CT performed one month after the thermotherapy in 13 cases showed that the primary focus in lung dwindled in 13 cases, and remained unchanged in 5 cases. Neither operative death nor post-operative complication was found. The life quality was improved in all the cases. The medium survival time was 16.8 months. One-year survival rate was 87%. One case survived more than 3 years, 4 cases survives more than 2 years (29, 30, 31, and 40 months respectively). Carcinoembryonic antigen decreased to normal and no carcinoma cell was found in pleural effusion. Flow cytometry showed that the tumor heteroploid peak diasappeared. Pyknosis and disintegration of nuclei, and apoptotic bodies of tumor cells planted on the surface of pleura were found by optical and electron microscopy. TUNEL showed apoptotic cells with brilliant yellow fluorescence. CONCLUSION: (1) Circular intrapleural hyperthermic perfusion is a new, safe, and effective treatment for MPE. (2) Apoptosis-mediated cytocidal function, improvement of body immunity after hyperthermic perfusion and continuous wash of the perfusion fluid are important mechanisms of intrapleural hyperthermic perfusion in treatment of MPE caused by lung carcinoma.

Adult↗

Noncovalent thrombin inhibitors incorporating an imidazolylethynyl P1.

A series of noncovalent tripeptidic thrombin inhibitors incorporating a unidazolylethynyl moiety at P1 was investigated. A number of compounds of this series were highly potent and selective versus trypsin, and several compounds demonstrated good oral absorption in rats (F = 58% for compound 19).

Acetylene↗

Identification of an optimal Ncx binding sequence required for transcriptional activation.

The Ncx gene encodes a homeobox containing transcription factor that belongs to the Hox11 gene family. We determined specific Ncx protein binding consensus DNA sequences. Optimal Ncx binding sequences were 5'-CGGTAATTGG-3' (TAAT core) and 5'-CGGTAAGTGG-3' (TAAG core), which coincided with the Hox11 binding sequence. Both Ncx and Hox11 could bind to the TAAT and the TAAG core oligonucleotide in vitro. However, they could efficiently transactivate the reporter plasmid linked to the TAAT core sequence but not to the TAAG core sequence. Thus, Ncx and Hox11 act as transcriptional activators via their target sequence, 5'-CGGTAATTGG-3'.

Binding Sites↗

Inelastic light scattering by gap excitations of fractional quantum hall states at 1/3 </= nu </= 2/3

We report observations of collective gap excitations of the fractional quantum Hall (FQH) states at filling factors nu = p/(2p+1) ( p = integer), for 1/3</=nu</=2/3, by inelastic light scattering. The collective gap energies at nu = 1/3, 2/5, and 3/7 show a drastic decrease as the value nu = 1/2 is approached. These energies and the one at nu = 3/5 display the linear scaling with (e(2)/epsilonl(0))/|2p+1| that is characteristic of composite fermions in Chern-Simons gauge fields. In a narrow range of nu centered at 1/2, where the FQH gaps collapse, we observe a new excitation mode which exists only at temperatures below 150 mK.

Journal Article↗

Image-guided percutaneous drainage of thoracic empyema: can sonography predict the outcome?

The aim of this study was to assess the safety and efficacy of image-guided percutaneous catheter drainage (IGPCD) of thoracic empyemas, and to correlate the outcome of IGPCD with the pre-procedural sonographic appearance. One hundred three patients (74 males and 29 females) with thoracic empyema (age range 1 month to 70 years, median age 28 years) underwent IGPCD. In 63 (61.17%) patients, IGPCD was the primary treatment modality; in 40 (38.84%) patients it was used after unsuccessful intercostal chest tube drainage (ICTD). Ultrasound was the main modality used for guidance; CT guidance was used in only 7 patients (6.8%). Eight- to 12-F pigtail catheters or 10- to 14-F Malecot catheters were used. The outcome was correlated with the pre-procedural US appearance (anechoic, complex non-septated or complex septated) of the empyema. The IGPCD technique was successful in 80 of 102 patients. Based on the US appearance, IGPCD was successful in 12 of 13 (92.3%) patients with anechoic empyemas; 53 of 65 (81.54%) patients with complex non-septated empyemas, and in 15 of 24 (62.5%) patients with complex septated empyemas. A statistically significant difference (p < 0.01) was seen in the outcome of IGPCD in the three categories. Twenty-two patients required further treatment: ICTD (n = 9; 2 of them later also underwent surgery); and surgery (n = 15). The duration of catheter drainage ranged from 2-60 days. No major complications were encountered. Percutaneous catheter drainage of thoracic empyemas with imaging guidance ensures accurate catheter placement with a high success and a low complication rate. Pre-procedural US can predict the likelihood of success of IGPCD.

Adolescent↗