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Biomedical subjects

J H Choi

Publications and source records attributed to J H Choi.

At least 19 recordsLinked to original sources
PubMed1991

Isolation and sequence analysis of a cDNA clone for a carrot calcium-dependent protein kinase: homology to calcium/calmodulin-dependent protein kinases and to calmodulin.

Recently, a novel type of calcium-dependent protein kinase (CDPK) that requires neither calmodulin nor phospholipids for activation, has been described in plants. We have isolated a cDNA clone for carrot CDPK by probing a library of somatic embryo cDNAs with oligonucleotides corresponding to highly conserved regions of protein kinases. The product of this gene overexpressed in Escherichia coli reacted strongly with monoclonal antibodies to soybean CDPK. The deduced amino acid sequence of carrot CDPK reveals two major functional domains. An N-terminal catalytic domain with greatest homology to calcium/calmodulin-dependent protein kinase type II from rat brain is coupled to a C-terminal calcium-binding domain resembling calmodulin. These features of the primary sequence explain how CDPK binds calcium and suggest a model for CDPK regulation based on similarities to animal calcium/calmodulin-dependent protein kinases.

Amino Acid Sequence↗
PubMed1991

A case of pulmonary cysticercosis.

Cysticercosis, which has a worldwide distribution is found in man, who is usually infected by eating inadequately cooked pork or other contaminated food. Cysticercosis develops most commonly in the muscles and brain. Pulmonary involvement is very rare and also difficult to recognize because pulmonary lesions caused by the presence of cysticerci are difficult to discern from pulmonary infiltrates, because other parasitic infestations or tuberculosis, as well as metastatic lesions, produce similar chest X-ray findings and similar clinical symptoms. We experienced a case of pulmonary cysticercosis confirmed at Gyeongsang National University Hospital by means of an open lung biopsy and treated successfully with praziquantel (50 mg/kg per day for 15 days). This case seems to indicate that pulmonary cysticercosis should be considered as a diagnostic possibility in patients with nodular infiltrates in the lungs, especially in endemic areas, until such infiltrates are otherwise explained.

Aged↗
PubMed1990

Prostanoid inhibition and group B hemolytic streptococci (GBS) induced neutropenia in newborn piglets.

GBS (Group B Hemolytic Streptococci) cause pulmonary hypertension with associated neutropenia. We investigated whether there is a correlation between the neutropenia of sepsis and GBS-induced pulmonary vasoconstriction, through study of the effects of inhibiting pulmonary vasoconstriction on the neutropenia of GBS in newborn piglets. Fifteen piglets were infused with GBS. After one hour, animals were given either a thromboxane inhibitor (DAZ), a combined cyclooxygenase/lipoxygenase inhibitor, BW755C, or placebo. With GBS infusion, WBC and PMN counts dropped steadily, from similar baselines, to 2250 +/- 570, 3300 +/- 500 and 5400 +/- 1100 cells/mm3 respectively (p less than 0.05; DAZ and BW vs. placebo). PMN's dropped similarly to 710 +/- 320, 2390 + 1240 and 3130 +/- 1050 cells/mm3 respectively (p less than 0.05; DAZ vs. BW and placebo). The drop in WBC's predominantly resulted from proportional decreases in PMN's (DAZ: r = 0.98; BW: r = 0.88; placebo r = 0.93). Compared to GBS alone, DAZ reduced pulmonary vasoconstriction, but exacerbated the granulocytopenia. BW755C similarly reduced pulmonary hypertension: however, it ameliorated the exacerbation of GBS induced neutropenia described above. These data imply that there is no direct correlation between GBS induced granulocytopenia and pulmonary hypertension.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1990

Mechanism of food restriction: protection of cellular homeostasis.

The major difficulty in defining the mechanisms for the action of food restriction relates to its diversity and lack of specificity. In searching for the common factor(s) and commonality involved in such diversified effects, a cellular homeostasis mechanism is proposed. A study initiated in our laboratory strongly indicates that the cellular homeostatic mechanism is seriously compromised by oxidative damage of free radical reaction with aging. Data on mitochondrial hydroperoxide, microsomal cytochrome P-450 breakdown, and reduction of cytosolic antioxidant capacity support the notion. Remarkably, food restriction attenuates all of these age-related changes. It is concluded therefore that food restriction preserves the homeostatic regulatory processes by maintaining the integrity of (i) membrane structure and function, (ii) proper redox state of cellular components, and (iii) detoxification process of xenobiotics.

Aging↗
PubMed1990

Pete Maravich's incredible heart.

Postmortem examination of a former professional basketball player revealed an abnormal heart, most notably a single coronary artery. The literature on single coronary arteries is briefly reviewed, and the possible mechanism which caused the patient's condition is considered. This case is particularly unusual because of the patient's profession, which is so physically demanding.

Adult↗
PubMed1990

Crossbow injuries.

The crossbow is an uncommon source of fatal injury. In Los Angeles County, two crossbow homicides have occurred in the past 20 years. Following the second case, a crossbow was test-fired into a fresh pork thigh, resulting in distinctive wounds. Experimental studies also showed that the vanes of the bolt (arrow) may be a source of trace material found in the wound.

Adult↗
PubMed1989

Regulation of acetyl CoA carboxylase mRNA in rat liver by high carbohydrate diet and insulin.

Acetyl CoA carboxylase contents in liver cytosol of rats refed a high carbohydrate diet or injected with insulin were measured by an immunoassay method in order to evaluate the effects of dietary carbohydrate and insulin treatment on the control in the amount of acetyl CoA carboxylase. Acetyl CoA carboxylase was purified 1,552 folds with a specific activity of 3.88 units/mg protein from livers of rats refed a high carbohydrate diet for 3 days following a 3-day fasting and the antibody was generated against the purified acetyl CoA carboxylase in a rabbit. Treatment of insulin (1.5 units/100g BW) and a high carbohydrate diet increased the amount of acetyl CoA carboxylase in liver cytosol by 3 times and 10 times, respectively, when compared to the enzyme content found in the control. The synthetic ratio of acetyl CoA carboxylase to total cytosolic proteins was 4 times higher in the insulin-treated group and 10 times higher in the high carbohydrated diet-treated group than the control group. The polysomal RNA contents in liver cytosols were 279% of the control in the insulin-treated group and 365% of the control in the high carbohydrate diet group. Also, the nascent chain of acetyl CoA carboxylase in polysome were 158% of the control in the insulin-treated group and 311% of the control in the high carbohydrate treated group. From these results, it is assumed that the increase of acetyl CoA carboxylase content in the rat liver cells by insulin treatment, or high carbohydrate diet refeeding has resulted from the increased polysomal acetyl CoA carboxylase mRNA, which is directly related to the biosynthesis of this enzyme.

Acetyl-CoA Carboxylase↗
PubMed1989

Prostaglandin E1 selectively reduces group B beta-hemolytic streptococci-induced pulmonary hypertension in newborn piglets.

Group B beta-hemolytic streptococci (GBS)-induced pulmonary hypertension was generated in ten newborn piglets. Intravenous infusions of either prostaglandin E1 (PGE1) (n = 5) or placebo (n = 5) were begun after 60 minutes of stable pulmonary hypertension. The effects of these interventions on cardiopulmonary hemodynamics were studied. Pulmonary artery pressure (PAP) increased similarly in both groups during the first 60 minutes of GBS infusion. By two hours after intervention, PAP was significantly lower in the animals given PGE1 (20 +/- 4 vs 32 +/- 5 mm Hg for PGE1 vs placebo). The ratio of pulmonary to systemic vascular resistance followed a pattern analogous to PAP, increasing with the GBS infusion, indicating selective pulmonary vasoconstriction. The pulmonary vascular resistance/systemic vascular resistance ratio decreased after intervention in the group given PGE1 only (0.25 +/- 0.08 vs 0.50 +/- 0.12 for PGE1 vs placebo), indicating selective pulmonary vasodilation. Transient systemic hypotension was noted at one hour after initiation of PGE1 infusion. Prostaglandin E1 infusion selectively improved GBS-induced pulmonary hypertension and hypoxemia in newborn piglets with only transient systemic hypotension.

Alprostadil↗
PubMed1988

Autopsy findings in the eyes of fourteen fatally abused children.

The eyes of fourteen fatally abused children and sixteen control cases were examined histopathologically. Ten of the abused children showed intraocular change. The most common ocular changes were subdural hemorrhage of the optic nerve and retinal hemorrhage which involved all the layers of the retina, but most commonly the nerve fiber layer, ganglion cell layer and inner nuclear layer. The presence of blood cavities within the retina partially supported the hypothesis of traumatic retinoschisis. The control cases of non-abused children rarely showed intraocular hemorrhage.

Child Abuse↗
PubMed1988

Cystic fibrosis--a case presented with recurrent bronchiolitis in infancy in a Korean male infant.

The aim of this case report is to draw the attention to the occurrence of cystic fibrosis (C.F.) in a Korean infant and thus increase the awareness for the diagnosis. The male infant was presented with a history of recurrent bronchiolitis manifested by severe cough, wheeze and dyspnea from three weeks of age, in whom the diagnosis of C.F. was clinically suspected and was confirmed by demonstration of two elevated sweat chloride levels (97 mEq/L and 99 mEq/L) in the patient. The diagnosis was delayed because the main manifestations of C.F. were the same as the main symptoms of common diseases such as cough, diarrhea and failure to thrive. C.F. is probably underdiagnosed in Korean population both because the diagnosis is not considered since the disease is thought to be uncommon or even not to occur and because diagnostic facilities including the quantitative iontophoresis sweat test are lacking.

Bronchiolitis↗
PubMed1987

Responses of broilers to dietary zinc bacitracin at two different planes of nutrition.

Four concentrations of Zn bacitracin (0, 50, 100 and 150 mg/kg) added to diets of two different planes of nutrition were fed to male broiler chicks for 7 weeks. Feeding broilers Zn bacitracin significantly improved growth rate and food conversion, and increased shank pigmentation. The effects of Zn bacitracin were independent of the plane of nutrition. Regression analyses revealed that the responses of birds were linear.

Animal Nutritional Physiological Phenomena↗
PubMed1986

Effects of pelleted or crumbled diets on the performance and the development of the digestive organs of broilers.

Two types (mash and crumble) of the starter ration (for 0 to 4 weeks of age) and two types (mash and pellets) of the finisher ration (for 4 to 8 weeks of age) were fed to broilers in a 2 X 2 factorial arrangement. Chicks fed the crumbled starter diet gained more weight and consumed more feed (P less than .01). Pelleting the finisher diet also significantly (P less than .01) improved weight gain and feed intake. Feeding the crumble during the starter period significantly (P less than .05) decreased gizzard weight at 4 weeks of age. Pelleting the finisher diet also significantly (P less than .01) reduced weights of the digestive tract and the gizzard at 8 weeks of age, compared to those fed the mash diet.

Animal Feed↗
PubMed1979

Blood phosphorus levels of laying hens at various time intervals after dosing with phosphoric acid.

Two experiments were conducted to study the pattern of change in serum inorganic phosphorus level in laying hens fed a diet containing 0.30% total phosphorus after dosing with a known amount of phosphorus. Serum phosphorus level of undosed hens was 2.5 mg/100 ml at oviposition in both experiments. After dosing with 100 mg of phosphorus in 10 ml of a phosphoric acid solution, serum phosphorus level increased sharply and reached a peak of about 7.0 mg/100 ml between 30 and 60 minutes in experiment 2. After the peak the elevated level of serum phosphorus decreased logarithmically until 5 to 6 hours after dosing and eventually decreased to 2.5 mg/100 ml which was the serum phosphorus level of undosed hens in experiment 1. The half-life of the elevated portion of serum phosphorus due to the dosing was about 100 minutes.

Animals↗
PubMed1979

Effects of different short-term dietary phosphorus levels on egg specific gravity and blood phosphorus of hens.

In the first 2 experiments, laying hens were fed a diet containing .30% phosphorus for a preliminary period of 3 days. At the beginning of the experimental period, hens were fed .30, .75, or 1.40% phosphorus with 3.50% calcium. Another group of hens was fed .75% phosphorus and 1.40% calcium. Specific gravity of the eggs and blood serum inorganic phosphorus were determined and compared with those from control hens continuously fed a diet containing .75% phosphorus and 3.50% calcium. Both high phosphorus and/or low calcium decreased the specific gravity of eggs and increased the serum phosphorus level. In experiment 2, hens were fed different levels of phosphorus at different times of the day. Birds receiving 1.40% phosphorus between 0700 and 0930 hr and .30% phosphorus between 0930 and 2000 hr (Treatment 2) laid eggs with higher specific gravity than hens fed .30% phosphorus between 0700 and 0930 hr and 1.40% phosphorus between 0930 and 2000 hr (Treatment 3). there was no further improvement in egg shell quality over that from hens fed .75% phosphorus for both time periods (0700 to 2000 hr). In both experiments it was apparent that the dietary phosphorus level affected egg shell quality.

Animals↗
PubMed1979

The phosphorus excretion pattern and balance during one egg cycle of the laying hen fed a phosphorus deficient diet with or without a single dose of phosphoric acid.

A balance trial was conducted to study the phosphorus excretion pattern of laying hens in relation to egg cycle. Excreta were collected quantitatively at 4, 8, 12, and 24 hr after oviposition. The amount of feed consumed corresponding to the excreta collected at a specific time interval was calculated using chromic oxide as a marker. The percent recovery of chromic oxide with laying hens was 73.97 +/- .56%. The maximum apparent digestibility of the dietary phosphorus, all of plant origin, was estimated to be 28.9 +/- 3.1% during 0 to 4 hr after oviposition when the endogenous excretion of phosphorus was theoretically minimized. Laying hens fed a diet containing .30% phosphorus excreted 24.3 mg less phosphorus than intake during the day, indicating that hens had to withdraw approximately 100 mg of phosphorus from their body to produce an egg. These hens excreted 63.1 +/- 27.0 mg of endogenous phosphorus during the 24 hr period, most of which was excreted during the period between 12 to 24 hr after oviposition of the previous egg. The excretion pattern of phosphorus was closely related to the egg laying cycle of the hen. Hens dosed with 100 mg of phosphorus, as a phosphoric acid solution, excreted more phosphorus than the undosed control birds. Approximately 45 mg of 100 mg of the phosphorus dose were excreted during the 24 hr period. At least 84.8 mg of the dosed phosphorus were absorbed within 12 hr and a part of it was excreted during the later period. Data indicated that the true absorption rate of the dosed phosphorus might have been much faster.

Animal Feed↗