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Biomedical subjects

K C Lee

Publications and source records attributed to K C Lee.

At least 19 recordsLinked to original sources
PubMed1992

Genotoxicities of nitropyrenes and their modulation by apigenin, tannic acid, ellagic acid and indole-3-carbinol in the Salmonella and CHO systems.

Four naturally occurring compounds, indole-3-carbinol (I3C), apigenin (Api), ellagic acid (EA) and tannic acid (TA), were tested for their inhibitory effects against 1-nitropyrene- (1-NP) or 1,6-dinitropyrene (1,6-DNP)-induced genotoxicity in Salmonella tester strains and Chinese hamster ovary (CHO) cells. Api and TA strongly inhibited the bacterial mutagenesis induced by nitropyrenes, while I3C and EA had little or no effect. For example, in TA98, 0.2 mumole Api resulted in 48% and 56% inhibition of the mutagenicity induced by 4 nmole 1-NP and 0.035 nmole 1,6-DNP, respectively. With an equal dose, TA caused 46% and 50% reduction of the mutagenicity induced by 1-NP and 1,6-DNP, respectively. As expected, a good correlation was observed between the antimutagenicity of nitropyrenes and their inhibitory effect on nitroreductase activity. This indicated that one of the possible antimutagenic mechanisms of Api or TA was to inactivate the metabolism of nitropyrenes. Two biological end-points, cytotoxicity and sister-chromatid exchange (SCEs), were used to screen the antigenotoxic effects of these compounds in CHO cells. At the sub-cytotoxic dose, I3C, Api and TA all protected against the cytotoxicity induced by 1-NP and 1,6-DNP, but only TA and Api gave a significant reduction of the frequency of SCEs. Moreover, this reduction was found to be highly dose-dependent.

Animals↗
PubMed1992

CD56 (NKH1)-positive hematolymphoid malignancies: an aggressive neoplasm featuring frequent cutaneous/mucosal involvement, cytoplasmic azurophilic granules, and angiocentricity.

CD56 (NKH1) expression is a rare phenomenon in malignant lymphomas, mostly confined to those occurring in the nasal or nasopharyngeal region. In this study we provide a detailed clinicopathologic analysis of nine patients with CD56-positive hematolymphoid malignancies occurring in sites other than the upper aerodigestive tract. The disease occurred predominantly in young and middle-aged men (mean age, 40 years) who often presented with swinging fever, skin rash, and/or hepatosplenomegaly, usually in the absence of peripheral lymphadenopathy. There was frequent involvement of the skin and mucosal sites, such as the salivary gland, lungs, and small intestine. The disease pursued a highly aggressive course, with most patients dying within weeks despite cytotoxic therapy. Although the cytologic appearances and immunophenotypic profile varied from case to case, the group of tumors could be unified by two morphologic features, namely, the presence of azurophilic granules in the cytoplasm of the neoplastic cells and the frequent occurrence of angiocentric and angiodestructive infiltrates. Since CD56 reactivity appears to confer a poor prognosis in hematolymphoid malignancies, we recommended inclusion of CD56 antibody in the routine panel for immunophenotypic analysis.

Adult↗
PubMed1992

Ossifying pleomorphic adenoma of the maxillary antrum.

An unusual case of pleomorphic adenoma with exuberant bone formation, occurring in the maxillary antrum of a 21-year-old male and showing repeated recurrence, is reported. In contrast to the endochondral ossification in the previous reported cases of pleomorphic adenoma, direct deposition of osteoid by metaplastic myoepithelial cells is suggested to explain the bone formation. The difficulties of distinguishing this tumour from osteosarcoma during intraoperative diagnosis are discussed.

Adult↗
PubMed1992

Angiomyofibroblastoma of the vulva. A benign neoplasm distinct from aggressive angiomyxoma.

Aggressive angiomyxoma of pelvic soft parts is a rare lesion with a high risk of recurrence. We report 10 cases of angiomyofibroblastoma, a hitherto uncharacterized benign tumor of the vulva histologically mimicking aggressive angiomyxoma. All patients had a vulval mass, often clinically diagnosed as a Bartholin's cyst. There was no recurrence after excision. The tumors were well circumscribed, measuring 0.5-12 cm in maximum dimension. They were characterized by alternating hypercellular and hypocellular edematous zones in which abundant blood vessels (predominantly of the capillary type) were irregularly distributed. Spindled, plump spindled, and oval stromal cells were aggregated around the blood vessels, sometimes forming solid compact foci, or were loosely dispersed in the hypocellular areas. Their nuclei were bland, but rare ones were enlarged and hyperchromatic in four cases. Some cells had abundant eosinophilic hyaline cytoplasm and eccentrically placed nuclei. Mitotic figures were absent or very sparse. Scattered throughout were thin, wavy strands or thick bundles of collagen. Mast cells were readily seen in eight cases. Immunohistochemically, the stromal cells were reactive for vimentin and desmin, but not cytokeratin, muscle-specific actin, alpha-smooth muscle actin, or S-100 protein. Ultrastructural studies showed well-developed rough endoplasmic reticulum, Golgi apparatus, abundant intermediate filaments, and pinocytotic vesicles in the stromal cells. Angiomyofibroblastoma can be distinguished from aggressive angiomyxoma by its circumscribed borders, much higher cellularity, more numerous blood vessels (which lack prominent hyalinization), frequent presence of plump stromal cells, minimal stromal mucin, and rarity of erythrocyte extravasation.

Adult↗
PubMed1992

Biliary tract invasion and obstruction by hepatocellular carcinoma: report of five cases.

Major biliary tract obstruction caused by tumour invasion is a rare manifestation of hepatocellular carcinoma. The authors had the opportunity to diagnose and treat five such cases, three of whom had features of acute cholangitis. The prevalence of both hepatocellular carcinoma and recurrent pyogenic cholangitis is high in patients from the Far East. The former may first present under the guise of the latter. Gastroenterologists and surgeons should be aware of hepatocellular carcinoma when managing these patients who present with obstructive jaundice, gross hepatomegaly and cholangitis.

Aged↗
PubMed1992

Contemporary management of cervical tuberculosis.

Although excisional biopsy has traditionally been required to diagnose cervical tuberculosis (TB), fine needle aspiration biopsy (FNAB) has also been found to be useful. The presentation and management of 47 patients diagnosed with cervical TB between 1984 and 1988 were retrospectively reviewed. Chest x-rays were normal in 58% of the patients, and purified protein derivative (PPD) skin testing was positive in 96%. When FNAB was used, TB could be suspected in 83% of cases and definitively established in 62%. Open biopsy correctly diagnosed cervical TB in all masses excised. Medical therapy alone resulted in resolution of disease in 94% of patients diagnosed by FNAB, and subsequent excisional biopsy was necessary in only one patient. The results suggest that FNAB is a useful initial procedure in the diagnosis of cervical TB. Excisional biopsy should be reserved for cases where no diagnosis by FNAB can be made, or for persistent cervical disease despite full-course antituberculous chemotherapy.

Adult↗
PubMed1992

[Preoperative percutaneous transhepatic portal vein embolization to extend the indications for hepatectomy and to increase the safety of extended hepatectomy for hepatocellular carcinoma].

The usefulness of preoperative percutaneous transhepatic portal vein embolization (PTPE) in extending the indications for hepatectomy and increasing the safety of extended hepatectomy for hepatocellular carcinoma was studied in 21 patients who underwent right hepatic lobectomy with PTPE of the right first portal branch (group E), in 15 such patients but without PTPE (group N), and in seven such patients who underwent PTPE at this location but could not undergo surgery (group U). The mean volume of the left lobe increased but the results of a 15-minute indocyanine green retention test were worsened 2 weeks after PTPE and again 4 weeks after hepatectomy, but these changes after hepatectomy were almost the same in groups E and N. The worsening of liver function and coagulation test results was less in group E than in group N. The mean prognosis score was better in group E two weeks after PTPE than before, but not in group U. The four patients in group E with high portal vein pressure (> or = 30 cmH2O) or a high prognosis score (> or = 50 points) after PTPE developed hepatic failure after surgery. Preoperative PTPE was useful in extending the indications for hepatectomy and increasing the safety of extended hepatectomy. Evaluation of the clinical course after PTPE was also useful when decisions about the operative method to be used were being made.

Aged↗
PubMed1992

Aggressive angiomyxoma. A report of four cases occurring in men.

Aggressive angiomyxoma is a distinctive, locally aggressive but nonmetastasizing soft tissue tumor of the pelvic soft tissues and perineum. This rare tumor occurs almost exclusively in adult women. We report four cases occurring in adult men, one each located in the scrotum, inguinal region, spermatic cord, and pelvis. The tumors were infiltrative, and were composed of fibromyxoid matrix sparsely populated by bland-looking spindled and stellate cells with delicate cytoplasmic processes. There were haphazardly scattered small and large blood vessels, some of which exhibited hypertrophy or hyalinization of the wall. Immunohistochemically, the stromal cells stained consistently for vimentin and variably for muscle-specific actin, but not alpha-smooth muscle actin, desmin, and S-100 protein. None of the four tumors recurred in follow-up times from 11 months to 6 years, although two previously reported cases in men recurred. This uncommon tumor occurring around the genital region in men merits wider recognition because of its potential for recurrence. It should be distinguished from benign tumors with low risk of recurrence on one hand, and from malignant myxoid tumors with metastatic potential on the other.

Adult↗
PubMed1992

Intraosseous lipoma. A clinicopathologic study of nine cases.

Intraosseous lipoma is one of the rarest benign primary tumors of the bone. The clinicopathologic features of nine cases of intraosseous lipoma, including one with multiple lesions of the lumbar spinous processes, were studied and analyzed. They represented 2.5% of all primary bone tumors seen in our institutions. They were subdivided into three groups according to their histologic appearances: Group 1, tumors consisting predominantly of viable fat cells; Group 2, tumors showing, in addition, areas of fat necrosis and calcification; and Group 3, lesions with extensive reactive ischemic bone formation and calcification, viable lipocytes and fat necrosis may or may not be visible. Since the tumor is located within the rigid confines of the bony trabeculae, the internal pressure created as it enlarges is believed to be most significant in the morphogenesis of the tumor. The recognition of this spectrum of morphologic features is important, since the secondary changes may predominate and overshadow the original lipomatous component, leading to the possibility of confusing it with other benign bone tumors, cysts, and bone infarction. A combined clinical, radiologic, and pathologic approach should be adopted in the diagnosis of this tumor.

Adult↗
PubMed1991

Simultaneous determination of prostaglandins E1, A1, and B1 by reversed-phase high-performance liquid chromatography for the kinetic studies of prostaglandin E1 in solution.

A method for the simultaneous determination of prostaglandins E1, A1 and B1 (PGE1, PGA1 and PGB1) in solution has been developed by reversed-phase high-performance liquid chromatography using a 3 microns C18 column. The mobile phase consisted of 35% acetonitrile in 0.002 M phosphate buffer (pH 3.5) and its flow-rate was 1.5 ml/min. Quantitative measurement was performed using a photodiode array detector system at 190, 220, and 280 nm for PGE1, PGA1 and PGB1, respectively. The method has been applied to the primary kinetic studies for reaction profile for PGE1----PGA1----PGB1 at 60 degrees C in pH 2.0, 7.2, 10.0 and 12.0 buffer solutions.

Animals↗
PubMed1991

Uptake of liposomes by cultured mouse bone marrow macrophages: influence of liposome composition and size.

A wide range of liposome compositions have previously been examined in vivo for their ability to affect the uptake of liposomes into cells of the reticuloendothelial (RE, mononuclear phagocyte) system (Allen, T.M. and Chonn, A. (1987) FEBS Lett. 223, 42-46; Allen et al. (1989) Biochim. Biophys. Acta 981, 27-35). In this study we have examined the ability of cultured murine bone marrow macrophages to endocytose liposomes of various compositions and have looked for correlations between the in vivo and the in vitro observations. Compounds which substantially decreased RE uptake of liposomes in vivo, such as monosialoganglioside (GM1) and a novel synthetic lipid derivative of polyethyleneglycol (PEG-PE), also greatly decreased liposome uptake by bone marrow macrophages in a concentration-dependent manner. Lipids which increase bilayer rigidity, such as sphingomyelin (SM) and cholesterol (CHOL), decreased both in vivo and in vitro uptake of liposomes. Likewise, positive correlations were observed between the in vivo behavior of liposomes containing phosphatidylserine (PS) or various gangliosides and the ability of these liposomes to be taken up by bone marrow macrophages. Total liposome uptake by macrophages increased with incubation time at 37 degrees C while very little liposome association with the macrophages was observed at 4 degrees C. Liposome uptake increased with liposome concentration and for liposomes composed of egg phosphatidylcholine (PC) uptake plateaued at 40 nmol lipid per mg cell protein. There was an inverse correlation between liposome size of extruded large unilamellar vesicles and their uptake by macrophages.

Animals↗
PubMed1991

The effects of iodixanol and iopamidol on hemodynamic and cardiac electrophysiologic parameters in vitro and in vivo.

Iodixanol is a new, nonionic, dimeric contrast medium which, in concentrations appropriate for radiographic use, is hypotonic with respect to plasma. The purpose of these in vivo and in vitro studies was to compare the effects of iopamidol, iodixanol formulated to isotonicity with sodium salts (sodium formulation), and iodixanol formulated to isotonicity with sodium, calcium, and magnesium salts (cationic formulation) on hemodynamic and electrophysiologic parameters. In vitro, the spontaneous rate of contraction by guinea pig right atrial and force development by right ventricular papillary muscles were evaluated in the presence of 1% to 100% (v/v) of the three contrast media. Iopamidol significantly (P less than .05) decreased the rate of atrial contraction to a greater extent than either formulation of iodixanol. Iopamidol decreased papillary muscle force development more than the sodium formulation of iodixanol (P less than .05). The cationic formulation of iodixanol had little effect (less than 30% change) on papillary muscle force development at concentrations up to 100%. The contrast media were also injected into the left coronary arteries of open-chest, anesthetized dogs at 0.8 mL/second for 5 to 30 seconds. All contrast media increased (P less than .05) systolic blood pressure (SBP), mean arterial pressure (MAP), and peak left ventricular pressure (LVP). Iopamidol increased LVP and LV end diastolic pressure to a greater extent (P less than .05) than the cationic formulation of iodixanol. We conclude that iopamidol affected cardiovascular parameters more than iodixanol.

Animals↗
PubMed1991

Basaloid-squamous carcinoma of the upper aerodigestive tract and so-called adenoid cystic carcinoma of the oesophagus: the same tumour type?

Basaloid-squamous carcinoma of the larynx, pharynx and base of tongue and the so-called adenoid cystic carcinoma of the oesophagus are rare but distinctive tumours associated with a grave prognosis. They occur most commonly in elderly males and present at an advanced stage. Our study of four such laryngeal tumours and five such oesophageal tumours shows that they are histologically and immunohistochemically identical, providing support for the idea that they are the same tumour type. They show a biphasic pattern in which basaloid tumour is intimately associated with a neoplastic squamous component which can be invasive or in situ. The basaloid component is in the form of invasive lobules with frequent comedo-necrosis and hyalinization. The constituent cells possess pale pleomorphic nuclei with frequent mitoses. Immunoreactivity for cytokeratin in the basaloid component is remarkable for its absence or weak and focal nature. Review of the literature shows that only a few cases of 'adenoid cystic carcinoma' of the oesophagus are bona fide examples of adenoid cystic carcinoma as it occurs in the salivary glands, while the others are identical to basaloid-squamous carcinoma of the upper aerodigestive tract. Their distinction is important because genuine adenoid cystic carcinoma is much less aggressive than basaloid-squamous carcinoma.

Actins↗
PubMed1991

Surgery of intracranial aneurysms at Yonsei University: 780 cases.

Seven hundred and eighty patients with intracranial aneurysm, which were surgically treated by the author since 1976, were analyzed. Strategies important for intracranial aneurysm surgery were the timing of surgery, preoperative preparation and intraoperative management. The best management outcome could be achieved by early operation, removal of subarachnoid blood clot, maintenance of circulating blood volume, administration of nimodipine, and meticulous surgical tactics to avoid pitfalls. Indications for aneurysm surgery in the acute phase were determined by intracerebral hematoma, angiographic findings, clinical grade, general physical status and readiness of the surgical team. Important goals to be considered during the operation were obtaining a slack brain, preparation of proximal control, protection of the brain, awareness of microsurgical anatomy, and complete dissection of the sac. The morbidity and mortality were 2.7% and 4.0%, respectively. The mortality was attributed to intracranial causes in 20 cases (poor grade, delayed ischemic deficits, rebleeding, postoperative infarction, and postoperative epidural hematoma), extracranial causes in 7 cases (pulmonary embolism, heparin induced intracerebral hemorrhage, hepatic failure, myocardial infarction, and gastrointestinal bleeding), and unknown problems in 5 cases. The postoperative intracerebral hemorrhage occurred in 16 cases and seemed to be caused by one or more of the following events: cerebral infarction developed during the preoperative period, occlusion of the cerebral veins during the Sylvian dissection, cerebral retraction and/or sudden change of intracranial hemodynamics. Hydrocephalus, almost always a communicating type as confirmed by isotope cisternography, was managed by lumboperitoneal shunt.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain Ischemia↗
PubMed1991

Neurosurgical application of fibrin adhesive.

We have tried fibrin adhesive, which mimics the end stage of plasmatic coagulation, in 26 patients with various neurosurgical problems such as: repair of cerebrospinal fluid (CSF) leaks, sealing of the vascular anastomosis sites, reinforcements of aneurysmal clippings, and hemostasis after resection of brain tumors. Presented in this report are 11 intracranial aneurysms, 11 brain tumors, 2 lipomyelo-meningoceles, and one each of cerebral arteriovenous malformation and torn dura resulting from a mastoidectomy. Procedures which seemed to be impossible or very difficult by conventional neurosurgical techniques could be accomplished in all cases without any complication. Our experience with fibrin adhesive suggests that it is a valuable adjuvant to various microneurosurgical procedures, and it may be potentially useful for protection of major cerebral veins and venous sinuses during cerebral retraction.

Adolescent↗