Biomedical subjects

J Y Lee

Publications and source records attributed to J Y Lee.

At least 19 recordsLinked to original sources

PubMed1992

ET-1 released histamine from guinea pig pulmonary but not peritoneal mast cells.

Endothelin(ET)-1 triggered histamine release of mast cells from pulmonary tissue but not from the peritoneal cavity of guinea pigs. The observed difference in response to ET-1 was attributable to a quantitative difference in ET-1 binding sites between both cells. The concentrations of ET-1 required for half maximal release of histamine and half maximal binding of [125I]ET-1 were approximately 0.05 and 0.08 nM, respectively. The release of histamine by ET-1 was a Ca(2+)-dependent but not a cytotoxic process. These observations, taken together, suggest that ET-1 induces histamine release from mast cells in a receptor-dependent fashion.

Animals↗

PubMed1992

Design, synthesis and conformational analysis of gamma-turn peptide mimetics of bradykinin.

Gamma-turns are regular secondary structure elements, found with some frequency in small peptides, that have been implicated in the biologically active conformations of several systems. This report describes the design, synthesis and conformational analysis of a non-peptide gamma-turn mimetic. Low energy conformations of the mimetic system exhibit good conformational agreement with an experimentally observed peptide gamma-turn. The mimetics were incorporated into the nonapeptide bradykinin, for which a gamma-turn, formed by residues Ser 6 to Phe 8, has been hypothesized to be a bioactive conformation. The results indicate that a bioactive conformation of bradykinin may include a reverse turn at this position.

Amino Acid Sequence↗

PubMed1992

Partially folded state of the disulfide-reduced form of human serum albumin as an intermediate for reversible denaturation.

The conformation of the fully disulfide-reduced state of human serum albumin was investigated by tryptophan fluorescence spectrum, CD analyses, and size-exclusion chromatography. Both the reduction of the native disulfide-bonded form under nondenaturing conditions and the refolding of the urea-denatured disulfide-reduced form under reduced conditions yielded almost exactly the same disulfide-reduced state with partially folded unique conformation that was clearly distinguished from either the native or fully denatured state. In addition, the interconversion between the urea-denatured reduced form and the partially folded reduced form was reversible with each other; by reoxidation, the partially folded reduced form was converted to the disulfide-bonded form. The conformation of disulfide-reduced serum albumin was highly variable depending on pH and ionic strength conditions. Thus, we concluded that the disulfide-reduced state with partially folded variable conformation is involved in the reversible interconversion between the denatured reduced form and the native disulfide-bonded form of human serum albumin.

Chromatography, Gel↗

PubMed1992

Replication complexes associated with the morphogenesis of rubella virus.

Thin section electron microscopy was used to investigate cellular changes associated with the replication of rubella virus (RV) in Vero cells and to compare these changes to those of the related alphavirus, Semliki Forest virus (SFV). Conspicuous membrane-bound cytoplasmic vacuoles analogous to the alphavirus replication complexes were observed in RV infected cells but not in mock infected cells. The vacuoles were characterised by membrane-bound vesicles measuring about 60 nm which often displayed an irregular dense core and/or a network of fibres. These vesicles were morphologically distinct from RV particles and were generally located at regular intervals on the inner side of the surrounding membrane of the RV replication complex. Degenerating cellular material was often found in the membrane-bound vacuole of a replication complex. The replication complexes were intimately associated with the rough endoplasmic reticulum (RER), which was localised 45-75 nm from the surrounding membrane of the replication complex. Parallel studies of replication complexes in SFV infected cells did not reveal such an intimate association with the RER. RV replication complexes appeared as early as 8 h post infection (p.i.), before detection of RV particles by electron microscopy, and their peak production at 24 h p.i. coincided with the time of maximum virus titre.

Animals↗

PubMed1992

Baseline frequency of sister-chromatid exchanges in 142 persons of the general Korean population.

Baseline frequencies of sister-chromatid exchange (SCE) were measured in lymphocytes of 142 healthy Koreans ranging in age from newborn infants to the fifties. The overall mean frequency of SCE was 8.78 +/- 0.24/cell. However, highly significant differences were found between individuals. The mean SCE values of the newborn babies and small children less than 10 years old were significantly lower than those of other age groups. No age effect was, however, observed in adolescent and adult subjects. Females had statistically higher SCE levels than males. The mean SCE frequencies of smokers, measured in male subjects more than 10 years old, were slightly, but statistically significantly, higher than those of non-smokers.

Adolescent↗

PubMed1992

Traumatic dislocation of testes and bladder rupture.

Traumatic dislocation of the testes with bladder rupture occurred in 2 multiply injured patients with pelvic fracture. One had a history of retractile testes and the other of previous testicular dislocation. Surgical correction was performed after closed reduction failed. These injuries must be recognized and treated promptly to maximize the likelihood of testicular salvage. If early intervention is not possible, duplex ultrasonography and pulsed Doppler analysis are the optional valuative studies.

Adult↗

PubMed1992

A new electron microscope positive staining method for viruses in suspension.

A new procedure for the positive staining of viruses in suspension, the Tokuyasu staining procedure (TSP), was evaluated using a non-enveloped virus, rotavirus; an enveloped virus, rubella virus and two glutaraldehyde-treated enveloped viruses, Human T Cell Lymphotropic Virus Type I (HTLV-I) and Human Immunodeficiency Virus Type 1 (HIV-1) as models. The TSP involves an initial staining of the virus with uranyl acetate (UA) followed by thin embedding in a mixture of UA and polyvinyl alcohol (PVA). Using aqueous UA for the TSP, a combination of positively and negatively stained particles was seen for both rotavirus and rubella virus. With glutaraldehyde-fixed HTLV-I and HIV-1, stain penetration did not occur and only negative staining was observed. The substitution of methanolic UA for aqueous UA in the TSP resulted in only positive staining of rotavirus and rubella virus. The change in procedure also resulted in stain penetration of the glutaraldehyde-fixed HTLV-I and HIV-1 to give positively stained particles. Some novel morphological features of rotavirus and rubella virus structure were observed by the TSP.

Glutaral↗

PubMed1992

Effects of retinoids on endothelial cell proliferation, prostacyclin production and platelet aggregation.

In addition to their anti-inflammatory and anti-cancer activities, retinoids have been shown to affect angiogenesis, endothelial proliferation and the process of wound healing. While peripheral vascular occlusion has not been observed as an adverse effect clinically, the effects of retinoids on prostacyclin production in endothelial cells and platelet aggregation are not known. We examined the effects of tretinoin, isotretinoin and etretinate (3.3 x 10(-8) to 3.3 x 10(-5) M) on cytotoxicity by 51Cr-release assay, growth and prostacyclin in bovine carotid endothelial cell cultures, and the aggregation of human platelets induced by ADP. All retinoids showed either no or only small effects on cytotoxicity and human platelet aggregation. Prostacyclin production was not significantly affected except for tretinoin and isotretinoin at 3.3 x 10(-5) M. Endothelial proliferation was affected by all three retinoids in a dose-dependent fashion; for tretinoin and isotretinoin an inhibitory trend was noted as the concentration increased but the reverse was true for etretinate. Retinoids at 3.3 x 10(-5) M induced alterations of typical endothelial morphology; the cells became fibroblastoid. The results of prostacyclin production and platelet aggregation in the present study are consistent with the absence of peripheral vascular occlusion as a side effect clinically.

Animals↗

PubMed1992

Extracorporeal shock wave lithotripsy and endoscopic management of renal calculi with urinary diversions.

A total of 12 patients with urinary diversions had calculi in 15 kidneys managed initially by extracorporeal shock wave lithotripsy (ESWL) in 12 kidneys and percutaneous nephrolithotripsy in 3. After 15 treatments with ESWL only 3 of the 12 kidneys (25%) became stone-free. Endoscopic procedures were used in 5 kidneys with fragments remaining after ESWL, and comprised percutaneous ultrasound lithotripsy in 2 and transstomal retrograde manipulations in 3. The 3 initial and 5 subsequent endoscopic procedures resulted in 6 of the 8 kidneys (75%) being stone-free. The poor results with ESWL are due to preexisting dilated upper urinary tracts and to immobility in obese myelomeningocele patients. Endoscopic procedures are the preferred method of treatment in these patients.

Adolescent↗

PubMed1992

Spontaneous bladder and uterine rupture with attempted vaginal delivery after cesarean section.

We report spontaneous bladder and uterine rupture in a patient undergoing oxytocin augmented labor while under epidural anesthesia after a previous cesarean section. The presenting signs were gross hematuria at placement of an indwelling catheter and fetal distress. Cesarean section produced a healthy newborn. The patient recovered satisfactorily after subtotal hysterectomy, bladder repair and transfusion.

Adult↗

PubMed1992

Molluscum contagiosum occurring in an epidermal cyst--report of 3 cases.

We present three unusual cases of molluscum contagiosum occurring in epidermal cysts. All of them are asymptomatic, elevated, oval nodules diagnosed clinically as epidermal inclusion cyst or prurigo nodularis. Histology showed true epidermal cysts containing molluscum bodies throughout the cyst wall and some type of laminated material within the cyst itself. The lesion, in all three cases developed in the pubic area of young adult men.

Adult↗

PubMed1992

Orthostatic hypotension occurs following alpha 2-adrenoceptor blockade in chronic prazosin-pretreated conscious spontaneously hypertensive rats.

1. Studies were performed to evaluate whether chronic prazosin treatment alters the alpha 2-adrenoceptor function for orthostatic control of arterial blood pressure in conscious spontaneously hypertensive rats (SHR). 2. Conscious SHR (male 300-350 g) were subjected to 90 degrees head-up tilts for 60 s following acute administration of prazosin (0.1 mg kg-1 i.p.) or rauwolscine (3 mg kg-1 i.v.). Orthostatic hypotension was determined by the average decrease (%) in mean arterial pressure (MAP femoral) over the 60-s tilt period. The basal MAP of conscious SHR was reduced to a similar extent by prazosin (-23%(-)-26% MAP) and rauwolscine (-16%(-)-33% MAP). However, the head-up tilt induced orthostatic hypotension in the SHR treated with prazosin (-16% MAP, n = 6), but not in the SHR treated with rauwolscine (less than +2% MAP, n = 6). 3. Conscious SHR were treated for 4 days with prazosin at 2 mg kg-1 day-1 i.p. for chronic alpha 1-adrenoceptor blockade. MAP in conscious SHR after chronic prazosin treatment was 14% lower than in the untreated SHR (n = 8). Head-up tilts in these rats did not produce orthostatic hypotension when performed either prior to or after acute dosing of prazosin (0.1 mg kg-1 i.p.). Conversely, administration of rauwolscine (3 mg kg-1 i.v.) in chronic prazosin treated SHR decreased the basal MAP by 12-31% (n = 4), and subsequent tilts induced further drops of MAP by 19-23% in these rats. 4. The pressor responses and bradycardia to the alpha 1-agonist cirazoline (0.6 and 2 micrograms kg-1 i.v.), the alpha 2-agonist Abbott-53693 (1 and 3 micrograms kg-1 i.v.), and noradrenaline (0.1 and 1.0 micrograms kg-1 i.v.) were determined in conscious SHR with and without chronic prazosin pretreatment. Both the pressor and bradycardia effects of cirazoline were abolished in chronic prazosin treated SHR (n = 4) as compared to the untreated SHR (n = 4). On the other hand, the pressor effects of Abbott-53693 were similar in both groups of SHR, but the accompanying bradycardia was greater in SHR with chronic prazosin treatment than without such treatment. Furthermore, the bradycardia that accompanied the noradrenaline-induced pressor effect in SHR was similar with and without chronic prazosin treatment despite a 47-71% reduction of the pressor effect in chronic alpha 1-receptor blocked SHR.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenergic alpha-Agonists↗

PubMed1992

Neurotropic malignant melanoma occurring in a stable burn scar.

Malignant melanoma occurring in burn scars is extremely rare. Nine cases are reported in the literature. We report a case of a small malignant melanoma arising in a stable thermal burn scar after a long latent period of 58 years. The case was unique in that it was of the de novo neurotropic variant. Fascicles of amelanotic, S100 protein-positive atypical spindle cells with neuroid appearance infiltrated deeply in the scarred dermis and perineural spaces. The pigmentation of the lesion was due to solar lentigo instead of atypical melanocytic proliferation in the overlying epidermis.

Biopsy↗

PubMed1992

Pathogenesis of hair infection and black dots in tinea capitis caused by Trichophyton violaceum: a histopathological study.

The majority of tinea capitis in southern Taiwan occur in adult women and are caused by Trichophyton violaceum. We report the histopathological findings of a series of 10 cases of tinea capitis caused by T. violaceum, the largest such study to date. Our study provides new information regarding the process of hair infection, mechanism of black dot formation, and chronicity of infection caused by this fungus. The cuticle remains intact. The fungi enter the proximal cortex where the cuticle is immature. They then colonize the proximal keratinized cortex and generate septate hyphae which transform gradually into arthrospores as they are carried upwards by the growing hair. At the infundibular level, the hair cortex is almost completely replaced by spores and swells, impeding further exit of the growing hair and causing the already weakened hair to coil up inside the infundibulum, forming a black dot. In one patient who had infection for more than 20 years, there were changes suggestive of cyclic reinfection of the same follicles which might contribute to the chronicity of the infection.

Adolescent↗

PubMed1992

Synthetic peptides analogous to the fimbrillin sequence inhibit adherence of Porphyromonas gingivalis.

Fimbriae are important in the adherence of many bacterial species to the surfaces they eventually colonize. Porphyromonas (Bacteroides) gingivalis fimbriae appear to mediate adherence to oral epithelial cells and the pellicle-coated tooth surface. The role and contribution of fimbriae in the binding of P. gingivalis to hydroxyapatite (HAP) coated with saliva as a model for the pellicle-coated tooth surface were investigated. 3H-labeled P. gingivalis or the radioiodinated purified fimbriae were incubated with 2 mg of HAP beads coated with whole human saliva (sHAP) and layered on 100% Percoll to separate unbound from sHAP-bound components. The radioactivity of the washed beads was a measure of the bound components. The binding of P. gingivalis 2561 (381) cells and that of purified fimbriae were concentration dependent and saturable at approximately 10(8) cells and 40 micrograms of fimbriae added, respectively. The addition of fimbriae inhibited binding of P. gingivalis to sHAP beads by 65%, while the 75-kDa protein, which is another major surface component of P. gingivalis 2561, did not show significant inhibition, suggesting that the fimbriae are important in adherence. Encapsulated and sparsely fimbriated P. gingivalis W50 did not bind to sHAP beads. On the basis of the predicted sequence of the fimbrillin, a structural subunit of fimbriae, a series of peptides were synthesized and used to localize the active fimbrillin domains involved in P. gingivalis adherence to sHAP beads. Peptides from the carboxyl-terminal one-third of the fimbrillin strongly inhibited P. gingivalis binding to sHAP beads. Active residues within the sequence of inhibitory peptide 226-245 (peptide containing residues 226 to 245) and peptide 293-306 were identified by using smaller fragments prepared either by trypsin cleavage of the peptide 226-245 or by synthesis of smaller segments of peptide 293-306. Hemagglutinin activity, lectinlike binding, and ionic interaction did not seem to be involved in this binding since lysine, arginine, carbohydrates, and calcium ions failed to affect the binding of P. gingivalis. The observation that poly-L-lysine, bovine serum albumin, and defatted bovine serum albumin, even at high concentrations, only partially blocked the binding of P. gingivalis indicates that hydrophobic interactions are not the major forces involved in P. gingivalis binding to sHAP beads. Protease inhibitors such as EDTA, leupeptin, pepstatin, 1,10-phenanthroline, and phenylmethylsulfonyl fluoride did not interfere with the binding of P. gingivalis. However, the binding of P. gingivalis to trypsin- or chymotrypsin-pretreated sHAP beads was reduced.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗

PubMed1992

Effect of varying rates of low-osmolarity contrast media injection for hepatic CT: correlation with indocyanine green transit time.

Contrast enhancement in hepatic computed tomography (CT) is related to multiple factors, including the amount of iodine injected, the rate of injection, and body weight. Fifty patients were randomized into two groups: 19 patients (group 1) received a 160-mL dose of Optiray 320 (ioversol) at 3.0 mL/sec, and 31 (group 2) received the same dose at 4.5 mL/sec. Indocyanine green dye transit time, peak enhancement, delayed enhancement, time to peak enhancement, age, and weight were statistically analyzed. Time to peak enhancement was significantly shorter in group 2 than in group 1 (62 seconds vs 73 seconds, respectively; P less than .01). Peak contrast enhancement averaged 88 HU +/- 19 in group 1 and 99 HU +/- 17 in group 2 (P = .06). Circulation time did not correlate with peak enhancement and thus does not assist in tailoring contrast medium injection for hepatic CT. Injection of contrast material at 3.0 and 4.5 mL/sec provides greater hepatic CT contrast enhancement than previously reported, with no significant risk of subcutaneous extravasation when injection is monitored carefully. These higher levels of contrast enhancement may assist in detecting and characterizing hepatic lesions.

Adult↗

PubMed1992

Cutaneous alternariosis in association with scabies or iatrogenic Cushing's syndrome.

Cutaneous alternariosis is rare. Most infections occur in immunocompromised hosts. We report the first three cases in Taiwan. The patients were elderly farmers residing in Tainan. They developed indolent, erythematous, ulcerated or crusted papules, plaques or pustules over the extensor aspect of the forearms or hands. Pure colonies of Alternaria sp were isolated from biopsy specimens in each case. The diagnosis was confirmed by detecting pleomorphic fungal elements in the dermis within suppurative, granulomatous infiltrates. All three patients were immunocompromised. They showed a negative reaction to an intradermal test of seven common antigens. Cases 2 and 3 had iatrogenic Cushing's syndrome. Cases 1 and 3 had extensive scabies, which in Case 1 was of the Norwegian type. To the best of our knowledge, scabies associated with alternariosis has not been reported previously. The infection showed spontaneous regression in Case 1; in Case 2, it resolved after seven weeks of intralesional amphotericin B at a dose of 1 mg/mL twice a week.

Aged↗

PubMed1992

[Kaposi's sarcoma in Tainan: report of five cases].

Kaposi's sarcoma (KS) is an uncommon cutaneous neoplasm with an increased incidence among Jews and Italians of Europe and North America and Negroes of equatory Africa. In recent years, several cases have been diagnosed in AIDS patients and in patients who have undergone organ transplantation or received immunosuppressant treatments. We have diagnosed five cases of KS over a 3-year period in our department. They include four men and one women, aged from 58 to 79 years, and who were born and had lived in Tainan. They all denied a history of homosexuality, multiple sexual partners, or drug abuse. HIV (Human immunodeficiency virus) screening test were negative. Two patients had taken 'black pills' (usually containing steroids) for a long period of time and also had generalized dermatophytosis. One of these two patients had a cytomegalovirus infection and died of Salmonella septicemia and upper GI bleeding. Although the English literature seems to indicate that KS is rare among Asians. Our present experience coupled with two other recently reported cases from Taiwan and the unpublished observations of some other dermatologists suggest that KS is not all that rare in Taiwan.

Aged↗