Biomedical subjects

C S Kim

Publications and source records attributed to C S Kim.

At least 19 recordsLinked to original sources

PubMed1992

Carnitine palmitoyltransferase activity in the rabbit choroid plexus: its possible function in fatty acid metabolism and transport.

The purpose of the present study was to measure the activity of carnitine palmitoyltransferase (CPT) in the lateral and fourth ventricular choroid plexus (LVCP, FVCP) as an example of an enzyme committed to mitochondrial long-chain fatty acid oxidation. The CPT activity measured with both assays determines total CPT activity, that is, the activity of both CPT-A (outer form) and CPT-B (inner form). CPT-assay 1 (forward reaction) activity was 893.3 +/- 44.5 mU/g and 803.3 +/- 71.3 mU/g (mean +/- S.E.M.) in LVCP and FVCP, respectively. CPT-assay 2 (backward reaction) activity was 3673.7 +/- 92.4 and 3417.0 +/- 277.1 mU/g in LVCP and FVCP, respectively. These data demonstrate that CPT activity is present in the rabbit choroid plexus, and that the activity is somewhat higher per gram wet weight of tissue than the activity observed in the skeletal muscle (CPT-assay 1 = 514.4 +/- 159, CPT-assay 2 = 2492 +/- 576 mU/g). CPT activity has been exclusively localized to the mitochondria of the liver, heart, kidney and the skeletal muscles. Our present study further demonstrates that the choroid plexus is another organ in which high activity of CPT exists.

Animals↗

PubMed1992

Bacteriophage lambda DNA fragments replicate in the Paramecium macronucleus: absence of active copy number control.

We show that bacteriophage lambda DNA fragments microinjected into the macronucleus of the ciliated protozoan Paramecium can replicate as unit-length linear molecules. These linear DNA molecules are substrates for the addition of Paramecium telomeres by an endogenous telomerase. The linear DNA pieces can exist at copy numbers much higher than that of typical endogenous macronuclear chromosomes. We show that the copy number of injected DNA many fissions after microinjection reflects that of the original input copy number, suggesting that active control of copy number does not occur. Instead, the results suggest that injected DNA is replicated once per cell division.

Animals↗

PubMed1992

The effect of phase differences on the time-dependent variation of the zeta potential of hydroxyapatite.

The osteoconductive nature of calcium phosphate ceramics (CPC) follows from several proven effects, such as a direct bone attachment and enhanced bone tissue formation. Mechanisms leading to these phenomena are still largely undiscovered. Specifically, little is known about the CPC surface and cell-driven reactions. These atomic and molecular level events are involved in tissue attachment and enhanced tissue formation. It is hypothesized that the zeta potential of these ceramics is directly related to the surface reactivity governing osteoconductivity. As a first step in our analysis, the zeta potential of stoichiometric and Ca-deficient hydroxyapatite was determined as a function of immersion time. It is concluded that, under the conditions of the experiment, the observations support the hypothesis in a dual way. First, the absolute values of the zeta potential which were measured are related to electrokinetic potentials known to cause substantial effect on the cellular activities and bone tissue formation when applied exogenously. Second, the magnitude and duration of the changes in zeta potential are related to an ion exchange between the hydrated layer around the ceramic and the ceramic surface, and a net precipitation of new material. If these findings could be confirmed in other solutions, i.e., solutions with a substantially equivalent composition as the fluids in developing bone tissue, a basis would be provided to explain the bridging of the ceramic surface with the surrounding developing tissue.

Biocompatible Materials↗

PubMed1992

Transient expression of adheron molecules during chick retinal development.

Neuritogenesis and synapse formation are transient phenomena mediated in part by filopodial attachments (Tsui, Lankford, and Klein, Proc. Natl. Acad. Sci. 82:8256-8260 1985). The attachments can be labeled by antisera against adherons, adhesive microparticles isolated from cell culture media (Tsui, Schubert, and Klein, J. Cell Biol. 106:2095-2108 1988). Here, two monoclonal antibodies raised against adherons have been found to recognize transiently expressed membrane antigens of developing avian retina. Early in development, monoclonal antibody (mAb) AD1 stained antigens that spanned the entire tissue. With time, immunoreactivity became restricted to optic fiber, ganglion cell, and inner plexiform layers. Immunoblots of embryonic day (E) 13 retina showed a broad band at 66-72 kD for particulate fractions and a fine band at 70 kD for soluble fractions. The particulate forms disappeared as retinas matured, but the soluble form did not. mAb AD2 initially labeled retina antigens of optic fiber, ganglion cell, and inner plexiform layers (IPL). Labeling in the plexiform layer showed discrete lamina. Immunoreactivity first appeared at E9, peaked at E15, and then disappeared shortly after hatching. In isolated cells, AD2 labeled small cell surface aggregates. Cytoarchitectural studies, using whole-mount transmission electron microscopy, showed AD2 antigen in cell surface microfilaments, including some that joined filopodia together. The adheron antigens recognized by mAbs AD1 and AD2 thus were (1) topographically restricted; (2) associated with cell surfaces; and (3) developmentally down-regulated. This pattern suggests a role in developmentally transient cell surface phenomena, such as neurite extension or junction biogenesis.

Animals↗

PubMed1992

Effects of chronic corticosteroids and vitamin A on the healing of intestinal anastomoses.

The ability of vitamin A to reverse the inhibitory effects of chronic corticosteroids on cutaneous and fascial wound healing is well established. To investigate this in the unique low-collagen environment of the intestinal anastomosis, 35 rabbits received twice-daily injections of either saline (control), dexamethasone (0.1 mg/kg/day), dexamethasone plus low-dose vitamin A (1,000 IU/kg/day), or dexamethasone plus high-dose vitamin A (10,000 IU/kg/day) for a 2-week period. Animals then underwent creation of single-layer, inverting small and large intestine anastomoses. All injections were continued postoperatively. A fifth group received only dexamethasone preoperatively and dexamethasone plus high-dose vitamin A postoperatively. On postoperative day 7, animals underwent in situ assessment of anastomotic bursting pressure and subsequent histologic examination using a modified Ehrlich/Hunt scale. Corticosteroids significantly impaired the healing of small and large intestine anastomoses, with decreased bursting pressures and histologic parameters at 1 week. Only high-dose vitamin A significantly reversed this inhibitory effect, whether given preoperatively or only postoperatively.

Anastomosis, Surgical↗

PubMed1992

Upregulation of nutrient transport in fetal rabbit intestine by transamniotic substrate administration.

Delivery of nutrients to the developing fetal gastrointestinal tract has been advocated as a potential prenatal treatment for intrauterine growth retardation. To examine the effect of intrauterine nutrient administration on the uptake capacity of the intestine, 16 maternal rabbits underwent bilateral ovarian-end transamniotic catheter placement on gestational Day 24. Study fetuses received a galactose solution; the contralateral controls received mannitol, a physiologically inert carbohydrate. Infusions were continued until Day 30 when an everted sleeve technique was used to measure radiolabeled uptake of both galactose and glucose in the proximal, middle, and distal small intestine. Mucosal scrapes were obtained, weighed, and the percentage of weight was calculated. Results were analyzed by ANOVA and Student's t test with P less than 0.05 being considered significant. There were 2 maternal deaths with 11 fetal pairs surviving (79%). There was increased uptake of galactose in the study fetuses compared to controls reaching significance in the middle and distal segments. Similarly, glucose uptake was significantly increased in the proximal and distal segments. Mucosal weight was increased in all regions, reaching significance in the proximal segment. Total intestinal uptake of galactose and glucose was significantly increased in the study fetuses compared to controls. Intraamniotic galactose infusion caused not only upregulation of its own mucosal transport but also that of glucose, along the entire fetal small intestine, achieving statistical significance particularly in distal segments. Fetal implications for transamniotic feeding are under investigation.

Amnion↗

PubMed1992

Maternal and fetal tissue distribution of L-carnitine in pregnant mice: low accumulation in the brain.

The distribution of L-carnitine was studied by whole-body autoradiography in pregnant CD-1 mice at 1, 2, 3, and 6 hr after receiving L-[14C]carnitine. Highest concentrations of carnitine were found in maternal tissues including liver, placenta, kidney, myocardium, and choroid plexus. High retention of tissue carnitine in excess of blood levels suggests the existence of concentrative uptake mechanism. Labeled carnitine was not detectable in either maternal or fetal brain. This suggests that the brain barrier systems limit the access of L-carnitine to the brain. In fetus, the level of carnitine was less than that seen in the maternal tissues, however, the tissue distribution was similar. The fetal tissue carnitine concentration increased with time. These findings suggest that relief of encephalopathy due to toxic organic anions in metabolic disorders following L-carnitine supplementation appears to be peripheral metabolic effects rather than direct access to the central nervous system. However, the physiological role for the concentrative uptake of L-carnitine by the choroid plexus remains to be determined. Transport of carnitine into fetal tissues via placenta further suggests the possibility of prenatal therapy in pregnancies at risk for certain inherited metabolic disorders.

Animals↗

PubMed1992

Characterization of silkworm chlorophyll metabolites as an active photosensitizer for photodynamic therapy.

Silkworm excreta containing chlorophyll metabolites have long been used for their medicinal activities in the Far East. The major chlorophyll derivative (CpD) fraction in the Me2CO extract from the silkworm excreta exhibits strong photodynamic action on mice and human tumor cells in vitro. The main CpD component was isolated, purified, and subjected to extensive structural and characterization studies to assess its photodynamic therapeutic activity. According to the spectral analyses, the structure of the major unknown CpD was determined to be 10-hydroxypheophytin a [1]. The CpD component possessed a high quantum efficiency (50%) for the photosensitized production of singlet molecular oxygen, thus providing a molecular basis for its photodynamic therapeutic efficiency. A further advantage is that the "photooxidation/degradation" product(s) from this CpD retains all the characteristics of a photodynamic sensitizer.

Animals↗

PubMed1992

Decreased sensitivity to metocurine during long-term phenytoin therapy may be attributable to protein binding and acetylcholine receptor changes.

Long-term phenytoin therapy induces resistance to the neuromuscular blocking effects of metocurine. The hypothesis that this is attributable to increased plasma protein binding of the drug (decreased free fraction) related to increased concentrations of alpha 1-acid glycoprotein (AAG) or attributable to the proliferation of acetylcholine receptors (AChR) at the muscle membrane was tested in the rat. After 14 days of phenytoin 40 mg.kg-1, administered intraperitoneally twice daily (n = 12), the neuromuscular pharmacodynamics were evaluated and compared with those of time-matched controls (n = 10). Protein binding was measured by equilibrium dialysis, AAG concentrations by radial immunodiffusion assay, and AChR by 125I-alpha-bungarotoxin binding. The effective dose for 50% inhibition of baseline twitch height (ED50) was significantly greater in the phenytoin group than in the control group (15.03 +/- 1.65 micrograms.kg-1 vs. 9.98 +/- 0.69 micrograms.kg-1, respectively). The concentrations of AAG increased gradually from 133.8 +/- 7.8 micrograms.ml-1 at day 0, to 343.1 +/- 58.0 micrograms.ml-1 at day 7, to 1,729.5 +/- 422.3 micrograms.ml-1 at day 14 in the phenytoin group. The induction of AAG concentrations in plasma was dependent on plasma phenytoin concentrations and was most prominent after 14 days of phenytoin (r = 0.77; P less than 0.01; n = 22). The free fraction of metocurine was significantly decreased in the phenytoin group compared to the control group (67.2 +/- 0.18% vs. 74.5 +/- 2.5%). There was a significant negative correlation between increased AAG concentrations and decreased free fraction (r = 0.65).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Octanoic acid produces accumulation of monoamine acidic metabolites in the brain: interaction with organic anion transport at the choroid plexus.

Effects of octanoic acid on monoamines and their acidic metabolites in the rat brain were analyzed by HPLC. Octanoic acid (1,000 mg/kg i.p.) elevated homovanillic acid levels by 54% in the caudate and 338% in the hypothalamus but increased 5-hydroxyindoleacetic acid (5-HIAA) levels in both the caudate and the hypothalamus by approximately 50% compared with the control. A lower dose of octanoic acid (500 mg/kg) increased 5-HIAA levels by 29% in the caudate and 20% in the hypothalamus. However, it did not produce any changes in the concentration of homovanillic acid in either the caudate or the hypothalamus. Treatment with octanoic acid also failed to change the level of dopamine, serotonin, and 3,4-dihydroxyphenylacetic acid in the caudate and the hypothalamus. The role of carrier-mediated transport in the clearance of 5-HIAA from the rabbit CSF was also evaluated in vivo by ventriculocisternal perfusion. Steady-state clearance of 5-HIAA from CSF exceeded that of inulin and was reduced in the presence of octanoic acid. Because this transport system in the choroid plexus is normally responsible for the excretion of the serotonin metabolite from the brain to the plasma, accumulation of endogenously produced organic acids in the brain, secondary to reduced clearance by the choroid plexus, could be a contributing factor in the development of encephalopathy in children with medium-chain acyl-CoA dehydrogenase deficiency who have elevated levels of octanoic acid systematically.

Acids↗

PubMed1992

Iron-sulfur centers as endogenous blue light sensitizers in cells: a study with an artificial non-heme iron protein.

The possible involvement of Fe-S clusters in photodynamic reactions as endogenous sensitizing chromophores in cells has been investigated, by using an artificial non-heme iron protein (ANHIP) derived from bovine serum albumin and ferredoxins isolated from spinach and a red marine algae. Ferredoxins and ANHIP, when exposed to visible light, generate singlet oxygen, as measured by the imidazole plus RNO method. Irradiation with intense blue light of the ANHIP-entrapped liposomes caused severe membrane-damage such as liposomal lysis and lipid peroxidation. In the presence of ANHIP, isocitrate dehydrogenase and fructose-1,6-diphosphatase were photoinactivated by blue light. However, all of these photosensitized reactions were significantly suppressed by a singlet oxygen (1O2) quencher, azide, but enhanced by a medium containing deuterium oxide. Further, the Fe-S proteins with the prosthetic groups destroyed did not initiate the blue light-induced reactions. In addition, the action spectrum for 1O2 generation from ANHIP was very similar to the visible absorption spectrum of Fe-S centers. The results obtained in this investigation appear consistent with the suggestion that Fe-S centers are involved in photosensitization in cells via a singlet oxygen mechanism.

Animals↗

PubMed1992

Corrosive esophageal stricture: safety and effectiveness of balloon dilation.

The safety and long-term effectiveness of fluoroscopically guided balloon dilation for corrosive esophageal stricture was evaluated in 22 patients with a follow-up period of more than 1 year (range, 13-52 months). The average interval between corrosive agent ingestion and initial balloon dilation was 18 years (range, 2 months to 51 years). Balloons with a diameter of 5-8 mm were used in the initial attempt. The caliber of the balloon catheter was increased gradually over subsequent dilations, up to a diameter that allowed patients to swallow solid foods. Dilation of more than 17 mm in diameter was performed in five patients. Patients underwent one to five sessions. Esophageal rupture occurred in seven patients and was treated nonoperatively in five and surgically in two. With exclusion of these latter two, 11 of 20 could tolerate swallowing all kinds of food and nine could tolerate swallowing most foods. Balloon dilation in corrosive esophageal strictures is effective, but the high rupture rate indicates the need for extra caution.

Acetates↗

PubMed1992

Systemic pilocarpine increases deposition of and decreases responsiveness to inhaled carbachol in sheep.

The purpose of this study was to determine whether excessive airway secretions could serve as a barrier function against inhaled particulate matter. To increase airway secretions, six conscious sheep were treated with pilocarpine (0.8 mg/kg i.v.). Pilocarpine increased pulmonary resistance (RL) and total aerosol deposition within five breaths (AD5) as determined by the rebreathing of an inert monodisperse aerosol. When RL had returned to baseline, AD5 remained elevated [21 +/- 2% (SE), P < 0.05] and tracheal secretions were increased (237 +/- 77%, P < 0.05) above the values before pilocarpine administration. A carbachol aerosol dose-response curve was carried out at this time and compared with a control carbachol dose-response curve by calculating the dose of carbachol required to increase RL by 400% (PD400). Mean PD400 was increased postpilocarpine by 53 +/- 18 (P < 0.05) and 85 +/- 25% (P < 0.05) when normalized for increased aerosol deposition. Thus, pilocarpine decreased airway responsiveness to inhaled carbachol despite increasing aerosol deposition. The pilocarpine-induced airway hyporesponsiveness to inhaled carbachol is consistent with the hypothesis that excessive secretions have a protective role in the airways.

Administration, Inhalation↗

PubMed1992

Percutaneous transhepatic biliary biopsy using gastrofiberscopic biopsy forceps.

To obtain a histopathologic diagnosis at the site of a biliary obstruction, we recently have performed 24 cases of biliary biopsy using gastrofiberscopic biopsy forceps (Olympus, Tokyo, Japan) via transhepatic tracts provided in the course of the procedure of percutaneous biliary drainage. Histopathologic diagnosis was successfully made at the first attempt of biopsy procedure but a second trial was made a week later in 6 cases who were negative for malignant cells on the first attempt. The histological results from the biopsy specimens were 18 adenocarcinomas, 5 chronic inflammations and one normal epithelium. Of 6 cases who were negative for malignant cells on forceps biopsy specimen, three cases were confirmed as adenocarcinoma of the ampulla of Vater, adenocarcinoma of the pancreas and chronic pancreatitis by surgical biopsy. The latter was a true negative result, which was diagnosed as chronic inflammation on forceps biopsy and verified as chronic pancreatitis by surgery. The remaining two cases were diagnosed as malignant obstructive jaundice by clinical and radiological follow-up findings. Major complications (bile peritonitis, bleeding, and hemopneumothorax) occurred in 3 patients, which mainly arose in the earlier period of study. This procedure can be performed at the same time as percutaneous transhepatic biliary drainage with low morbidity or mortality, and although the potential for perforation of bile ducts and injury to adjacent blood vessels is considered it is a useful addition to existing biopsy techniques for yielding material sufficient for histologic analysis.

Adult↗

PubMed1992

Fecal lysozyme: an unreliable marker for colorectal cancer.

High levels of lysozyme have been reported to be present in the feces of patients with colorectal cancer. It has been suggested that fecal lysozyme could prove useful in the early detection of colorectal cancer, but that further work is needed. The present investigation reports on the measurement of fecal lysozyme in 23 colorectal cancer patients and 39 healthy controls. The mean fecal lysozyme level for the cases was 13.3 +/- 2.8 micrograms/g stool compared with 12.5 +/- 2.6 micrograms/g stool for the controls. The median level for the cases was 8.7 micrograms/g stool compared with 6.6 micrograms/g stool for the controls. Forty-three percent of the cases and 31% of the controls had fecal lysozyme levels above 10 micrograms/g stool. None of these differences were statistically significant. The results of this study indicate that fecal lysozyme would be of no use in the early detection of colorectal cancer.

Adenoma↗

PubMed1991

Kinetic analysis of L-carnitine uptake by the choroid plexus.

Choroid plexuses from the lateral (LVCP) and fourth ventricles (FVCP) of rats or rabbits were incubated in artificial cerebrospinal fluid (CSF) containing 1 microM [14C]L-carnitine with various concentrations of L-carnitine ranging from 0.01 mM to 1.0 mM. The time course of 1 microM [14C]L-carnitine uptake by the choroid plexus indicated that it increased linearly for the first 15 min. Steady-state levels were reached by 30 min with tissue concentrations more than 20 (FVCP)- to 30 (LVCP)-fold greater than the concentration in the medium. The uptake of [14C]L-carnitine was increased with increasing concentrations of the substrate in the medium and this uptake followed Michaelis-Menten kinetics. The uptake by the rat choroid plexus took place against a concentration gradient via a saturable process and kinetic analysis revealed Km of 32 microM (LVCP) and 34 microM (FVCP) and Vmax of 21 (LVCP) and 17 nmol/ml/min (FVCP), respectively. Ouabain inhibited the uptake by 51% (FVCP) and 48% (LVCP) and hypothermia (0 degrees C) produced inhibition by 97% (FVCP) and 96% (LVCP), respectively. However, the uptake of L-carnitine was not sensitive to probenecid or tyrosine, which indicates the presence of an independent carrier for L-carnitine in the choroid plexus. Similar results were obtained with the rabbit choroid plexus.

Animals↗

PubMed1991

Dobutamine digital echocardiography for detecting coronary artery disease.

To assess the value of dobutamine echocardiography for detecting coronary artery disease (CAD), 70 men (mean age 62 +/- 8 years) presenting for coronary angiography were prospectively studied. Dobutamine (2.5 to 40 micrograms/kg/min) was infused in 3-minute stages. Digital echocardiograms were recorded on-line at baseline, during low- and high-dose dobutamine infusion, and at recovery. An echocardiogram positive for CAD was defined as one showing a new wall motion abnormality induced by dobutamine. Compared with coronary angiography, the overall sensitivity of dobutamine echocardiography for detecting CAD was 86%, specificity 95% and accuracy 89%. The sensitivity for detecting 3-vessel CAD was 100%, 89% for 2-vessel and 69% for 1-vessel CAD. The accuracy of predicting multivessel disease by 2 methods was 71% and 84%, respectively. Heart rate at the echocardiographic ischemic threshold was lower in patients with 3- and 2-vessel CAD versus 1-vessel CAD (89 +/- 17, 95 +/- 18 and 118 +/- 18 beats/min, respectively, p less than 0.01); rate-pressure product was also lower in patients with 3- and 2-vessel CAD versus 1-vessel CAD (12.7 +/- 3.6, 13.7 +/- 2.8 and 18.9 +/- 44 x 10(3) beats/min x mm Hg, respectively, p less than 0.01). Heart rate was the most important physiologic determinant of ischemia induced by dobutamine. There were no major complications during the study. Thus, dobutamine digital echocardiography is an excellent test for identifying CAD and should be beneficial in patients unable to exercise.

Adult↗

PubMed1991

An improved model of experimental gastroschisis in fetal rabbits.

Previous animal models of gastroschisis have been associated with high mortality and variable degrees of intestinal evisceration. Using current fetal surgical techniques, an improved model of gastroschisis in fetal rabbits was developed. Twenty-eight time-mated New Zealand white rabbits underwent hysterotomies and fetal exposure on gestational day 25 (33-day gestation). Control fetuses (C) underwent fetal manipulation only. Gastroschisis fetuses (GS) had creation of right midabdominal wall defects. Twenty-five of 28 does (89%), 9 of 13 C fetuses (69%), and 18 of 22 GS fetuses (82%) survived. At the time of cesarean delivery 5 days later, GS fetuses had significantly lower body weights, intestinal lengths, and mucosa/submucosa height ratios (a measure of bowel wall edema), and significantly greater intestinal densities when compared with C fetuses (P less than .05, t test). This study demonstrates that (1) gastroschisis abdominal wall defects can be created in fetal rabbits with high survival rates; (2) experimental gastroschisis is associated with a profound decrease in fetal weight; and (3) eviscerated intestine is heavier, shorter, and thickened compared with normal control intestine, mimicking the clinical situation.

Abdominal Muscles↗