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Biomedical subjects

C B Kim

Publications and source records attributed to C B Kim.

At least 55 records · Page 3Linked to original sources
PubMed1990

The cause of dysphagia in uncomplicated sliding hiatal hernia and its relief by hiatal herniorrhaphy. A roentgenographic, manometric, and clinical study.

Patients with an uncomplicated sliding hiatal hernia frequently experience dysphagia. The present study shows, using video barium contrast esophagograms, that the cause of dysphagia in 60% of these patients is an obstruction to the passage of the swallowed bolus by diaphragmatic impingement on the herniated stomach. Manometrically this was reflected by a double-hump high pressure zone (HPZ) at the gastroesophageal junction, and specifically to the length and amplitude of the distal HPZ and the length of the intervening segment between the two HPZs. The former represents the degree of the diaphragmatic impingement on the herniated stomach and the latter the size of the supradiaphragmatic herniated stomach. Surgical reduction of the hernia resulted in relief of dysphagia in 91% of the patients.

Barium Sulfate↗
PubMed1988

In vitro carbon monoxide production by the small intestine of suckling and adult Wistar rats: effect of parenteral tin-protoporphyrin.

Single subcutaneous doses (25 mumol/kg body weight) of tin-protoporphyrin (TP), a potent competitive inhibitor or heme oxygenase (HO), were administered to both suckling and adult Wistar rats. The effect of TP on the carbon monoxide excretion rate (VeCO), an index of total bilirubin formation, and on in vitro carbon monoxide (CO) production by the small intestine were evaluated. Whereas the VeCO of the adult group was decreased (p less than 0.0005) after TP, that of the suckling rat was unchanged. Gradients of CO production along the small intestine were observed in sucklings as well as adults; however, these gradients were in opposite directions. Intestinal CO production was greatest in the adult duodenum, decreasing distally; conversely, the CO production was greatest in the suckling ileum, decreasing proximally. No significant difference in CO production between control and TP-treated adult intestinal mucosa was observed. In sucklings, a significant reduction of intestinal CO production in the TP-treated rats was detected in the duodenum only (p less than 0.05). The results suggest that suckling rats differ from adults in terms of the capacity to produce CO and the direction of the gradient of CO production along the intestine. We conclude that (1) TP may not substantially decrease the in vivo production of CO by the small intestine at a dose which inhibits hepatic and splenic heme oxygenase, and (2) because after a heme load, heme is excreted into the intestine after TP administration, heme-degrading, CO-producing processes in the intestine may contribute to an animal's VeCO under such conditions.

Aging↗
PubMed1988

Lack of inhibition of intestinal heme oxygenase by antibiotics and tin-protoporphyrin.

We assessed the in vivo and in vitro effects of antibiotics and tin-protoporphyrin (TP) on intestinal heme oxygenase (HO) activity using a gas chromatographic assay. This method measures the carbon monoxide produced from heme in the presence of NADPH. After in vivo administration of kanamycin (10 mg/kg body weight), ampicillin (200 mg/kg body weight) or neomycin (60 mg/kg body weight) with or without TP (65 mumol/kg body weight) to suckling rats, no significant difference in HO activity along the small intestine was observed. In vitro exposure of adult rat intestinal preparations to the antibiotics showed no significant decrease in HO activity between control and experimental tissue preparations. A concentration-dependent stimulatory effect of neomycin was observed. Subcutaneous administration of TP (25 mumol/kg body weight) to adult male Wistar rats revealed no significant inhibition of the intestine. However, in vitro addition of TP (12.5 microM) to the control tissue preparations of adult Wistar rats revealed highly significant inhibition in liver and spleen when compared to the unexposed control tissues. In contrast, when TP was added to control intestinal preparations no inhibition was observed. These findings suggest that suckling rat intestinal heme oxygenase is not inhibited by in vivo treatment with high concentrations of kanamycin, ampicillin, or neomycin. Furthermore, these antibiotics are not in vitro inhibitors of adult rat intestinal HO. Finally, adult rat intestinal HO is not inhibited either in vivo or in vitro by a concentration of TP that significantly inhibits liver and spleen activity.

Animals↗
PubMed1988

Foveal flicker sensitivity in healthy aging eyes. I. Compensating for pupil variation.

Photopic temporal contrast sensitivity for healthy eyes of observers 65 years old and older is compared with retinal-illuminance-matched sensitivity of younger eyes. The older observers are significantly less sensitive for frequencies between 10 and 45 Hz. Although there is a slight shift to slower flicker rates in the mean contrast sensitivity function for older observers, this trend is not statistically significant, suggesting that there is relatively little loss of temporal resolving power of the visual system with healthy aging. These are preliminary results from an ongoing study of temporal contrast sensitivity in healthy aging eyes.

Adult↗
PubMed1987

Tin protoporphyrin inhibits carbon monoxide production in suckling mice.

The carbon monoxide excretion rate (VeCO) of groups of 1-day-old mice was measured after administration of two separate doses of 50 nmol of tin protoporphyrin (TP) per gram of body weight. The mean VeCO of the saline-treated control groups over the study period was 1.50 +/- 0.26 nmol/g/h, and that of the TP-treated groups was 1.35 +/- 0.29 nmol/g/h. Tin protoporphyrin treatment reduced the CO excretion by approximately 14% in 2-day-old mice over 24-48 h.

Animals↗
PubMed1986

Smooth frequency discrimination functions for foveal, high-contrast, mid spatial frequencies.

Intensive testing of spatial-frequency discrimination thresholds for 21% contrast gratings between 2.9 and 7.8 cycles/degree (c/deg) reveals, on average, smooth functions conforming to Weber's law. Discrimination overall is very sensitive, indicating highly skilled performance, but there are no consistent peaks or troughs. Individual, single-run functions do vary, resulting in candidate peaks and troughs that might be proposed to reflect true variations in an observer's sensory discrimination capacities. However, these features do not replicate from session to session nor from observer to observer. We do find consistent differences in overall sensitivity level between testing methods, with randomized presentation of reference frequencies giving significantly higher thresholds than blocked reference frequencies.

Adult↗
PubMedDate not supplied

Prescription behaviours of office-based doctors to standardized common cold patients in Korea.

PURPOSE: To investigate real pictures of prescription behaviours of office-based doctors in Korea, especially focusing on the prescription of oral antibiotics and injections. METHODS: Prescription information was collected from 18 standardized patients (SPs) with the symptoms of the common cold who visited doctors' office. RESULTS: For these patients antibiotics were prescribed by 96 doctors (64.7%) out of 148 and the rate of antibiotic prescription increased with age of doctors, increasing number of medicines, and cost of medicines. Analgesics were most frequently prescribed (91.8%), and gastrointestinal drugs (81.6%), antitussivies (61.2%), antithistamines (61.2%), decongestants (59.2%), mucolytics (51.0%) and proteolytic enzymes (32.7%) followed. More than half of the doctors intended to give injections to the patients, which was higher among internists and doctors prescribed more medicines. CONCLUSIONS: Antibiotics and injections were frequently prescribed for mild common colds in Korea. Action to ensure judicious use of antibiotics and injection is urgent.

Adult↗
PubMedDate not supplied

Effects of aging on the densities, numbers, and sizes of retinal ganglion cells in rhesus monkey.

We used sterological procedures that yield unbiased estimates to quantify the densities, numbers, and soma sizes of retinal ganglion cells in seven young adult and six old rhesus monkeys. The retinae were flat mounted so that we could determine whether there are different aging-related losses in different retinal regions. The mean (+/-standard deviation) total number of ganglion cells was 1,529,039 +/- 115,260 in young-adult retinae and 1,556,698 +/- 165,056 in old retinae, a difference that was not statistically significant. There also were no significant differences between young and old retinae in the densities or total numbers of ganglion cells in the four retinal quadrants, in four concentric retinal zones from fovea to peripheral retina, or in smaller hemiretinal regions of the concentric zones. Ganglion-cell soma sizes also did not differ significantly between young and old animals. Moreover, counts of the largest ganglion cells, which probably correspond to P alpha ganglion cells, revealed no selective loss of these cells with aging. These results are consistent with our previous anatomical and physiological studies of the LGN. Together they suggest that the retino-geniculate pathways are relatively unaffected by aging in the rhesus monkey.

Aging↗
PubMedDate not supplied

Influence of the superior colliculus on responses of lateral geniculate neurons in the cat.

The superior colliculus (SC) projects to all layers of the cat's lateral geniculate nucleus (LGN) and thus is in a position to influence information transmission through the LGN. We investigated the function of the tecto-geniculate pathway by studying the responses of cat LGN neurons before, during, and after inactivating the SC with microinjections of lidocaine. The LGN cells were stimulated with drifting sine-wave gratings that varied in spatial frequency and contrast. Among 71 LGN neurons that were studied, 53 showed a statistically significant change in response during SC inactivation. Control experiments with mock injections indicated that some changes could be attributed to slow waxing and waning of responsiveness over time. However, this could not account for all of the effects of SC inactivation that were observed. Forty cells showed changes that were attributed to the removal of tecto-geniculate influences. About equal numbers of cells showed increases (22 cells) and decreases (18 cells) in some aspect of their response to visual stimuli during SC inactivation. The proportion of cells that showed tecto-geniculate influences was somewhat higher in the C layers (68% of the cells) than in the A layers (44% of the cells). In addition, among cells that showed a significant change in maximal response to visual stimulation, the change was larger for cells in the C layers (64% average change) than in the A layers (26% average change) and it was larger for W cells (61% average change) than for X and Y cells (29% average change). Nearly all of the X cells that showed changes had an increase in response, and nearly all of the Y cells had a decrease in response. In addition, across all cell classes, 80% of the cells with receptive fields < 15 deg from the area centralis had an increase in response, and 80% of the cells with receptive fields > or = 15 deg from the area centralis had a decrease in response. None of the LGN cells had significant changes in spatial resolution, and only three cells had changes in optimal spatial frequency. Ten cells had a change in contrast threshold, 25 cells had a change in contrast gain, and 29 cells had a change in the maximal response to a high-contrast stimulus. Thus, our results suggest that the tecto-geniculate pathway has little or no effect on spatial processing by LGN neurons. Rather, the major influence is on maximal response levels and the relationship between response and stimulus contrast.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMedDate not supplied

Relationship between numbers of retinal ganglion cells and lateral geniculate neurons in the rhesus monkey.

Studies of the numbers of retinal ganglion cells and lateral geniculate nucleus (LGN) neurons in primates suggest that the numbers of both types of neurons may vary over a two-fold range from one individual to another. This raises the question of whether the numbers of ganglion cells and LGN neurons are related or vary independently from individual to individual. We used stereological procedures to obtain unbiased estimates of the numbers of both cell types in seven rhesus monkeys. We found no significant correlation (rs = -0.21) between the numbers of retinal and LGN cells in the same animals. In agreement with previous studies, the average ratio of the number of retinal ganglion cells that project to the LGN and the number of LGN cells was approximately 1:1. However, this ratio varied over a two-fold range, from 0.78:1 to 1.64:1, in individual animals. These results have important implications for understanding the mechanisms of retino-geniculate development and for understanding the connectional wiring between the retina and LGN.

Aging↗
PubMedDate not supplied

VEP and PERG acuity in anesthetized young adult rhesus monkeys.

This study used the swept spatial-frequency method to compare retinal and cortical acuity in anesthetized young adult rhesus monkeys. Visual evoked potentials (VEPs) and pattern electroretinographic responses (PERGs) were recorded from 25 monkeys (age range: 4-12 years) anesthetized with a continuous infusion of propofol. The stimuli were temporally countermodulated sine-wave gratings that increased in spatial frequency within a 10.24-s period. All animals were refracted using acuity estimated from the zero micro-volt intercept of the linear regression of evoked potential amplitude on spatial frequency. Average sweep acuities were 23.7 cycles/deg +/- 1.5 S.E.M. and 23.1 cycles/deg +/- 1.8 S.E.M. for the PERG and VEP, respectively. VEP and PERG acuities were within the range expected based on acuities estimated from behavioral studies in macaques. PERG and VEP acuities were highly correlated (r = 0.90) and equally sensitive to spherical blur. On a subset of animals, test-retest reliability of animals, and interocular correlations, were high (r = 0.87 and r = 0.83, respectively). Increasing propofol dosage 8-fold did not degrade PERG or VEP acuity. This study demonstrates that high spatial-frequency acuities can be rapidly obtained from young adult rhesus monkeys under a wide dose range of propofol anesthesia using the swept spatial-frequency method.

Anesthesia↗