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Biomedical subjects

C Park

Publications and source records attributed to C Park.

At least 235 records · Page 13Linked to original sources
PubMed1991

Functioning free latissimus dorsi muscle transplantation: anterogradely positioned usage in reconstruction of extensive forearm defect.

We present a patient with successful functional recovery of a severely injured upper extremity after a microneurovascular free latissimus dorsi muscle and combined composite skin were transplanted with an anterograde position. In our patient, the anterogradely positioned usage of the lastissimus muscle offered two major advantages; one advantage was the direct anastomosis of a more proximal healthy uninjured recipient nerve without interpositional nerve graft, and the other, one-stage coverage including the elbow wound with combined scapular skin flap. From our result, we deduce that a neurovascular free latissimus dorsi muscle transplantation with an anterograde position is selectively indicated in functional recovery of an extensively injured forearm.

Adult↗
PubMed1991

A single-stage two-flap method of total ear reconstruction.

A single-stage two-flap method of total ear reconstruction in congenital microtia is reported. This method was derived from the one-stage reconstruction described by Song and Song. Two flaps defined by vascular basis were elevated on the mastoid area: the superficial skin flap supplied mainly by subcutaneous pedicled arteriole perforators from the posterior auricular artery and the deeper axial-pattern fascial flap including the posterior auricular artery itself. The ear framework, exaggeratedly carved using autologous rib cartilage, could be inserted easily between the two flaps, simultaneously producing the auriculocephalic angle and the conchal wall. Intraoperative expansion of the skin flap and postoperative external ear molding also were performed to create aesthetically pleasing ears.

Adolescent↗
PubMed1991

Evaluation of 99mTc-hexamethylpropyleneamine oxime cerebral blood flow mapping after acute focal ischemia in rats.

Although the blood flow tracer hexamethylpropyleneamine oxime is now widely used for cerebral blood flow mapping using single-photon emission computed tomography, its uptake into acutely ischemic brain has not been well studied. We performed a double-label autoradiographic study in which 99mTc-hexamethylpropyleneamine oxime uptake was compared with [14C]iodoantipyrine-derived cerebral blood flow 0.5, 24, and 72 hours after middle cerebral artery occlusion in 11 rats. We noted excellent correspondence between iodoantipyrine and hexamethylpropyleneamine oxime autoradiograms at all times with both simultaneous tracer injection and 30-minute separation of tracer injections. When the ischemic and hyperemic areas were measured from the same brain section using the two different tracers, hexamethylpropyleneamine oxime underestimated the iodoantipyrine-derived areas by less than 1% (95% confidence interval -2.9% to 2.3%). The maximum discrepancy (-19%) was seen at high flows. When the two tracers were injected separately, the uptake of hexamethylpropyleneamine oxime was not linear compared with iodoantipyrine-derived cerebral blood flow, but the relation became linear after the Lassen correction factor was applied. Hexamethylpropyleneamine oxime uptake thus accurately represents cerebral blood flow 0.5-72 hours after acute cerebral ischemia.

Animals↗
PubMed1991

Normal splenic size in infants and children: sonographic measurements.

The purpose of this study was to establish guidelines for normal splenic size at different ages by using a simple and reproducible sonographic method. Two hundred thirty patients, from neonate to 20-year-old, had sonography because of abdominal and/or pelvic problems unrelated to the spleen. Findings on sonograms of the liver and kidneys were normal in all cases. Splenic size was measured by obtaining a coronal view that included the hilum, while the patient was breathing quietly. The greatest longitudinal distance between the dome of the spleen and the tip (splenic length) was measured and correlated with age, height, and weight. The following guidelines are proposed for the upper limit of normal splenic length based on this simple, easy to use, one-measurement technique: splenic length no greater than 6.0 cm at 3 months, 6.5 cm at 6 months, and 7.0 cm at 12 months, 8.0 cm at 2 years, 9.0 at 4 years, 9.5 cm at 6 years, 10.0 cm at 8 years, 11.0 cm at 10 years, 11.5 cm at 12 years, 12.0 cm at 15 years or older for girls, and 13.0 cm at 15 years or older for boys. Twenty-two patients with known abnormalities of the spleen were randomly selected and their splenic lengths compared with the proposed guidelines; in each case, the length of the spleen exceeded the upper limit of normal for that age. Normal values of a single measurement of the greatest longitudinal diameter of the spleen, from the dome to the tip measured at the hilum in the coronal plane, were obtained in patients from newborn to 20 years old.

Adolescent↗
PubMed1991

Effect of a modified rectus tuck on anterior ciliary artery perfusion.

Strabismus surgery results in the permanent interruption of anterior ciliary blood flow, predisposing the eye to anterior segment ischemia (ASI). A primate model was used to assess the effectiveness of a new muscle-scleral tuck for preserving anterior ciliary artery circulation. The model consisted of removing 3 rectus muscles from both eyes of 2 rhesus monkeys, then performing a tuck on the inferior rectus (IR) right eye while leaving the left IR as a control. Four weeks later, a modified tuck was performed on the virgin left IR. Fluorescein iris angiograms of both eyes were obtained, and preoperative angiograms at 5-15 sec. showed normal 360 degrees perfusion. Postoperative follow-up angiograms showed segmental superior temporal filling defects and preservation of perfusion in the distribution of the IR. Comparison of fellow eyes tucked vs control IR showed no difference in the filling pattern in both monkeys. Comparison of the same eye before and after tuck also showed essentially the same filling pattern in all 4 eyes with preservation of inferior circulation. Our conclusion is that the modified tuck preserves the anterior ciliary blood flow and may be useful as a muscle-strengthening procedure in patients predisposed to developing ASI.

Animals↗
PubMed1991

Effects of iodinated fatty acid ester on human hepatocellular carcinoma cells.

The interaction between Lipiodol and cells was studied by treating Lipiodol in a human hepatocellular carcinoma cell line(Hep) and mouse fibroblast cell line (L929). Irregular, sustained radioactivity was released from both cell lines shortly after incubation in the radioiodinated Lipiodol mixed media. Lipiodol droplets were found to be firmly attached to the cells following the incubation and these cells were strongly positive for fat stains. The radioiodinated Lipiodol demonstrated the same behavior of accumulation within the cell and on the cell membrane. Although the amount of Lipiodol attached was almost equal in both of the cell lines, the final amount accumulated in the cells was larger in the Hep cells. The accumulation of Lipiodol within the cell and on the cell membrane may play a significant role for its selective targeting and its prolonged retention in the solid tumor.

Carcinoma, Hepatocellular↗
PubMed1991

Gamma-interferon effects on human fibroblasts from Tenon's capsule.

Gamma-interferon (G-IFN) exhibits antiproliferative effects, inhibits collagen synthesis by fibroblasts, and may help to regulate the turnover of fibrous tissue. Fibroblasts from Tenon's capsule are cellular components that contribute to unsuccessful glaucoma filtration surgery. Therefore, the authors studied the effects of G-IFN on growth, wound closure, collagen synthesis, and extracellular matrix in cultured human Tenon's capsule fibroblasts (HTCF). HTCF incubated with G-IFN at doses of 1 to 1000 U/ml showed cellular heterogeneity, with some cells showing morphologic changes characteristic of senescence, and a dose-dependent inhibition of wound closure. At 1000 U/ml, G-IFN reduced collagen synthesis by 57%, reduced immunofluorescent staining of collagen type I and fibronectin network, and altered the organization of actin microfilaments into large cable-like structures. Cell proliferation and viability were not affected at any concentration of G-IFN. These results suggest that G-IFN may be useful to modulate wound healing after filtration surgery.

Cell Division↗
PubMed1990

Intrinsic religiousness and religious coping as life stress moderators for Catholics versus Protestants.

Two prospective studies were conducted to test the stress-moderating effects of intrinsic religiousness and overall religious coping on the depression and trait anxiety of Catholic and Protestant college students. Both studies found a significant cross-sectional interaction between controllable life stress and religious coping in the prediction of Catholics' depression, with religious coping serving a protective function at a high level of controllable negative events. Both studies also found a significant prospective interaction between uncontrollable life stress and intrinsic religiousness in the prediction of Protestants' depression; the relationship between uncontrollable stress and depression was positive for low intrinsic Protestants, flat for medium intrinsic Protestants, but negative for high intrinsic Protestants. The findings are discussed in terms of their implications for the role of religion in life stress adjustment.

Adaptation, Psychological↗
PubMed1990

The gastric juice urea and ammonia levels in patients with Campylobacter pylori.

The authors studied gastric juice ammonia and urea nitrogen levels to determine how they are altered by gastric Campylobacter pylori (CP) infection. Patients with chronic gastritis (20), peptic ulcer (24), hepatic cirrhosis (10), chronic renal failure (13), or gastric remnant (20) were included. Endoscopic biopsy specimens stained with the Warthin-Starry stain were evaluated for the presence of CP. Blood and gastric juice analysis was performed for 11 of the patients with chronic renal failure and 37 patients from the remaining groups. CP was identified in gastric biopsies from 50 of 87 (57.5%) patients, including 87.5% with peptic ulcer and 40-50% of those with chronic gastritis, cirrhosis, chronic renal failure, or gastric remnant. CP infection had no effect on blood urea nitrogen or blood ammonia levels in any group of patients. The urea nitrogen level of gastric juice was higher in patients with chronic renal failure than in other groups but was not related to CP infection. CP infection was associated with a significant increase in gastric juice ammonia levels, both in patients with chronic renal failure (23.3 mmol/L vs. 2.90 mmol/L; [P less than 0.05]) and in other groups (5.48 mmol/L vs. 1.26 mmol/L [P less than 0.0001]). The authors conclude that elevation of gastric juice ammonia level is an indicator of gastric CP infection.

Adult↗
PubMed1990

Distribution of Lipiodol in hepatocellular carcinoma.

Intrahepatic distribution of Lipiodol and I-131 Lipiodol infused via the hepatic arteries was evaluated in six patients with HCC who had undergone hepatic lobectomy or segmentectomy. CT scan and gamma camera radiograph confirmed that the oily contrast material or I-131 radioactivity accumulated selectively in the tumor over a long period. One to two thirds of the tumor mass appeared necrotic, although the extent tended to be larger in the case of radioactive Lipiodol infusion. The tumor cells contained numerous lipid globules within the cytoplasm. Also, oil red 0 stain demonstrated that the individual tumor cells had non-globular lipid on their surface. In conclusion, Lipiodol leaks out of the vascular spaces to attach to the cancer cell membrane as a non-globular lipid as well as to enter the cancer cells as a globular lipid. This phenomenon specific to cancer cells suggests a biochemical membrane change which may have occurred during carcinogenesis, causing alteration of membrane transport and cell death.

Adult↗
PubMed1990

Effects of glutamines and glutamates at sites of covalent modification of a methyl-accepting transducer.

Chemotactic transducer proteins of Escherichia coli contain four or five methyl-accepting glutamates that are crucial for sensory adaptation and gradient sensing. Two residues arise from posttranslational deamidation of glutamines to yield methyl-accepting glutamates. We addressed the significance of this arrangement by creating two mutated trg genes: trg(5E), coding for a transducer in which all five modification sites were synthesized as glutamates, and trg(5Q), in which all five were glutamines. We found that the normal (3E,2Q) configuration was not an absolute requirement for synthesis, assembly, or stable maintenance of transducers. Both mutant proteins were methylated, although Trg(5Q) had a reduced number of methyl-accepting sites because two glutamines at adjacent residues were blocked for deamidation and thus could not become methyl-accepting glutamates. The glutamine-glutamate balance had striking effects on signaling state. Trg(5E) was in a strong counterclockwise signaling configuration, and Trg(5Q) was in a strong clockwise signaling induced by ligand binding, and alanines substituted at modification sites had an intermediate effect. Chemotactic migration by growing cells containing trg(5E) or trg(5Q) exhibited reduced effectiveness, probably reflecting perturbations of the counterclockwise/clockwise ratio caused by newly synthesized transducers not modified rapidly enough to produce a balanced signaling state during growth. These defects were evident for cells in which other transducers were not available to contribute to balanced signaling or were present at lower levels than the mutant proteins.

Bacterial Proteins↗
PubMed1990

Melanosis coli--histochemical and immunohistochemical comparison of the pigments of melanosis coli and Dubin-Johnson syndrome.

We compared the pigment of melanosis coli with the pigment of Dubin-Johnson syndrome, melanin, and lipofuscin. The pigment of melanosis coli appeared similar to lipofuscin in that it stained positively with periodic acid-Schiff, oil red-0 and Victoria blue stains and revealed negative reactions to the immunohistochemical stains for S-100 protein and neuron specific enolase, but had similarity to melanin as shown by the positive reaction to Fontana-Masson stain and negative autofluorescence. The pigment of Dubin-Johnson syndrome showed the same histochemical and immunohistochemical characteristics as that of melanosis coli. The results indicate that the pigments of melanosis coli and Dubin-Johnson syndrome are identical and are variants of lipofuscin.

Colonic Diseases↗
PubMed1989

Adaptational "crosstalk" and the crucial role of methylation in chemotactic migration by Escherichia coli.

We investigated roles of methylation in bacterial chemotaxis by characterizing a methyl-accepting transducer protein incapable of methylation because of amino acid substitutions at the modification sites. Mutant Trg protein recognized ligand and generated excitatory signals that affected flagella but was unable to mediate efficient adaptation or net cellular migration in a relevant chemical gradient. Defects caused by lack of methyl-accepting sites on Trg were suppressed by a sufficient cellular content of other transducer molecules with functional methyl-accepting sites. These observations establish directly that methylation is crucial for transducer-mediated chemotaxis and that neither phosphotransfer reactions among the soluble Che proteins nor other interaction among those chemotactic components can effectively fulfill the functions of methylation. Suppression was correlated with adaptational "crosstalk" in which unoccupied methyl-accepting transducers acquired methyl groups, thus apparently substituting effectively for blocked methyl-accepting sites on the transducer. A plausible model for this phenomenon is that increased methylation of unstimulated transducers results from global inhibition of the demethylating enzyme in a cell with a normally active methyltransferase and no available methyl-accepting sites on the stimulated, mutant transducer. Thus methylation can perform its roles in adaptation and gradient sensing even if modification occurs on molecules different from those that recognize the stimulating compound. This observation emphasizes the central role of methylation and the modular nature of the chemosensory system.

Bacterial Proteins↗