Biomedical subjects

C Lee

Publications and source records attributed to C Lee.

1,162 records · Page 65Linked to original sources

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Effect of spermatocele fluid on growth of human prostatic cells in culture.

The present study was carried out to investigate whether testicular fluid derived from a spermatocele contains substance(s) that promote the growth of human prostatic cells in culture. Human spermatocele fluid was centrifuged to sediment spermatozoa. The supernatant was then added to cultures of human prostatic stromal or epithelial cells that were isolated from surgical specimens of benign prostatic hyperplasia. Addition of spermatocele fluid in quantities of 1 microgram/ml of protein resulted in a significant increase in the number of both prostatic stromal and epithelial cells at the end of a 6-day culture period. Human serum at equivalent protein concentrations in the culture medium had no stimulatory effect. At least two separate growth-promoting factors were found in spermatocele fluid, one for stromal cells and one for epithelial cells. The mitogen for stromal cells was heat labile and persisted after treatment with activated charcoal. The factor for epithelial cells was heat stable but was removed by charcoal treatment. These observations are consistent with the concept that the human testis secretes nonandrogenic substances that can promote prostatic growth.

Cell Division↗

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The mucopolysaccharidoses: characterization by cranial MR imaging.

PURPOSE: To characterize MR findings in mucopolysaccharidoses (MPS), to aid in diagnosis and categorization, and to define the role of MR in preoperative evaluation. MATERIALS AND METHODS: Six children with Hurler syndrome (MPS IH), five with Hunter syndrome (MPS II), and three with Sanfilippo A syndrome (MPS IIIA) were studied by routine T1-weighted and T2-weighted images at 1.5 T. MR findings were graded retrospectively. RESULTS: All had hallmark cribriform changes (sieve-like or multicystic) involving peri- and supraventricular, parietal, white matter (12), corpus callosum (8), and basal ganglia (4), which did not enhance. The cerebellum and brain stem were not involved with these cribriform changes. The most severe degree of cribriform changes occurred in children with Hunter and Hurler syndromes, correlating with non-central nervous system somatic involvement, but inversely related to degree of atrophy, ventricular enlargement, and white matter changes. Mental retardation was most severe in children with Hurler syndrome and correlated with chronicity of the disease. Severity of mental retardation did not correlate with severity of cribriform changes. CONCLUSIONS: Based on our observations, we postulate that in the natural course of MPS, cribriform changes occurred first, followed by white-matter changes and, last, atrophy. More severe degrees of cribriform changes plus involvement of the corpus callosum may suggest a poorer prognosis. Optimal therapeutic intervention may be at the time of cribriform changes before atrophy has occurred. MR can define and grade these changes.

Adolescent↗

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Learning cues.

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Education, Nursing↗

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Biodegradable ceramic-collagen composite implanted in rabbit tibiae.

To develop an artificial bone substitute that would be gradually degraded and replaced by the regenerating natural bone, a carbonate apatite type I atelocollagen (82/12 in v/v%) composite was designed. The carbonate apatite synthesized at 58 degrees C demonstrated a crystallinity similar to that of natural bone. Type I atelocollagen was purified from human umbilical cords. Carbonate apatite-atelocollagen composite rods (diameter 6 mm x height 10 mm) were irradiated by ultraviolet ray (wave length 254 nm) for 4 hr to increase the collagen fibrillar cross links. Rabbit tibiae were dissected to prepare an artificial total bone defect (length 10 mm). The composites and porous hydroxyapatite rods, sintered at 1200 degrees C, were implanted into the defects and the tibiae were fixed by external osseofixators. The implanted composites were gradually degraded in the lesions, and the regenerated bone totally replaced the defects within 6 weeks, while the hydroxyapatite rod implanted lesions were not replaced by bone. No specific histologic abnormalities appeared in either the hydroxyapatite or composite rod implanted lesions.

Animals↗

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Effect of TGF-beta 1, TGF-alpha, and EGF on cell proliferation and cell death in rat ventral prostatic epithelial cells in culture.

A tissue culture system for rat prostatic epithelial cells was developed, and the effect of epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha), and transforming growth factor beta 1 (TGF-beta 1) on these cells was evaluated. The primary culture was prepared by DNAse/collagenase dissociation of minced ventral prostates. Cells were initially plated in RPMI-1640 medium containing 10% fetal bovine serum to allow the preferential attachment of stromal cells. Twenty-four hours later, the unattached epithelial cells were replated in WAJC-404 medium supplemented with insulin (5 micrograms/ml), transferrin (5 micrograms/ml), and selenious acid (5 ng/ml). Bovine pituitary extract (BPE) (30 micrograms/ml), EGF (10 ng/ml), and TGF-beta 1 (0, 0.1, and 1.0 ng/ml) were added either alone or in combination according to experimental requirements. The rate of cell proliferation was assessed by counting the total cell number and by [3H]thymidine incorporation. Prostatic epithelial cells exhibited a bell-shaped growth curve in a span of 7-8 days, with a growth peak at day 3 or 4 of culture. Treatment of cells with EGF or TGF-alpha resulted in a concentration-dependent increase in cell growth, whereas addition of TGF-beta 1 into the culture resulted in an inhibition of cell proliferation that could be reversed with increasing concentrations of EGF. Cell death was assessed using the terminal deoxynucleotidyl transferase (TdT)-mediated immunoperoxidase-digoxigenin nick end labeling technique and the trypan blue exclusion test. Epithelial cells cultured in media containing EGF had the lowest incidence of cell death. Cells cultured in the absence of EGF demonstrated a marked increase in cells undergoing cell death. The addition of TGF-beta 1 into the EGF-depleted medium caused a further increase of cell death. These results indicated that cell proliferation and cell death in rat prostatic epithelial cells in culture could be modulated by EGF and TGF-beta 1. The former stimulated cell proliferation and prevented cell death, whereas the latter inhibited proliferation in the presence or absence of EGF and induced cell death.

Animals↗

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Porcine aortic wall flexibility. Fresh vs Denacol fixed vs glutaraldehyde fixed.

It has been postulated that, in theory, stentless bioprosthetic heart valves provide improved hemodynamics and durability over their stented counterparts. A number of glutaraldehyde modified porcine stentless valves are currently either on the market or in clinical trials. Polyepoxy compound as an alternative cross-linking reagent to glutaraldehyde for bioprostheses has been reported to mitigate calcification. The present study was to investigate the effect of the fixation methods on porcine aortic wall flexibility. Ring specimens were selected from three groups of porcine roots: fresh, low pressure glutaraldehyde fixed, and low pressure Denacol (polyepoxy compound) fixed. Pulled between two rods on a tensile tester, a ring specimen's load-deformation relationship was recorded and analyzed to numerically compute the tissue modulus at low strains. The results showed that the Young's moduli were 0.113 +/- 0.036, 0.494 +/- 0.113, and 1.320 +/- 0.292 MPa (mean +/- SD, n = 10) for the fresh, Denacol fixed, and glutaraldehyde fixed aortic walls, respectively. The Denacol fixed aortic wall was more flexible than the glutaraldehyde fixed one. It was also found that the Denacol fixed aortic wall maintained most of the natural residual strains, while the glutaraldehyde fixed aortic wall did not.

Animals↗

PubMedDate not supplied

Camptothecin delivery systems: the antitumor activity of a camptothecin-20-0-polyethylene glycol ester transport form.

BACKGROUND: This study was designed to assess the efficacy of polyethylene glycol(PEG) conjugated camptothecin, PEG-alpha-camptothecin, a novel water soluble transport form (prodrug) of the naturally derived antitumor drug, 20-(S)-camptothecin. MATERIAL AND METHODS: Circulatory retention studies were performed in non-tumor bearing mice injected intravenously with 300 mg/kg of PEG-alpha-camptothecin. Therapeutic efficacy was evaluated in both a murine P388/0 leukemia and a colorectal HT-29 carcinoma xenograft model. RESULTS: PEG-alpha-camptothecin had a blood t1/2 alpha of less than 5 minutes and a t1/2 beta of 3.5 hours. Five intraperitoneal injections of 3.2 mg/kg/day 20-(S)-camptothecin equivalents of PEG-alpha-camptothecin in our leukemia model resulted in significant survival over untreated controls (P < 0.001), with a mean time to death of treated versus control (T/C ratio) of 2.94 and a cure rate of 80% (n = 20). The colorectal carcinoma xenograft model demonstrated that 2-3 mg/kg/day 20-(S)-camptothecin equivalents of PEG-alpha-camptothecin given 5 days a week for 5 weeks could reduce an initial tumor burden of 300 mm3 by more than 90% without any signs of overt toxicity. CONCLUSION: This water soluble transport form of 20-(S)-camptothecin and its underlying technology may have clinical application.

Animals↗

PubMedDate not supplied

Prognostic significance of mammographic detection in a cohort of conservatively treated breast cancer patients.

PURPOSE: This study aimed to evaluate the prognostic significance of nonpalpable mammographically detected breast cancer in a cohort of conservatively treated breast cancer patients. METHODS AND MATERIALS: The records of 953 patients with invasive stage I and II breast cancer treated with conservative surgery and radiation therapy prior to January 1990 were reviewed. Mode of presentation with reference to clinical and mammographic findings was recorded. For statistical analysis, patients were divided into two groups: 748 patients presented with clinically palpable masses with or without mammographic abnormalities (PALP), and 205 presented with nonpalpable mammographically detected tumors (MGDET). RESULTS: Patients in the MGDET group presented with cancers at earlier stages of disease, had tumors of smaller pathological size, were more often hormone-receptor positive, and less frequently required adjuvant systemic therapy. As of December 1995, with a median follow-up of 11.6 years, the MGDET group had a higher 10-year overall survival rate (82% vs 68%) and a superior 10-year distant-metastasis-free rate (87% vs 75%). The ipsilateral breast tumor relapse rate was similar between the PALP and MGDET groups. When broken down by age (< 50 years vs > or = 50 years), the benefits of early detection remained apparent with a statistically significant superior distant-metastasis-free rate in women under age 50 in the MGDET group compared with women under age 50 in the PALP group. In a multivariate analysis, mammographic detection remained an independent prognostic factor for distant-metastasis-free survival. CONCLUSION: Patients presenting with nonpalpable mammographically detected invasive breast cancer have a favorable prognosis compared with their counterparts presenting with clinically palpable masses. Although the issue of lead-time bias cannot be addressed adequately in this retrospective review, the favorable prognosis with respect to disease-free survival and breast conservation is quite evident. The high probability of disease-free survival and breast preservation in these patients should further encourage the widespread using of screening mammography and the increased use of breast-conserving surgery with radiation therapy.

Breast Neoplasms↗

PubMedDate not supplied

A study of chest infections in HIV seropositive patients in Kuala Lumpur.

A retrospective study of 144 adults with HIV infection was conducted to investigate the prevalence of upper and lower respiratory tract infections (URTIs and LRTIs). The patients were divided into two groups: those with acquired HIV through intravenous drug abuse (IVDA), and those who had acquired HIV through 'other' risk behaviours. LRTIs were more prevalent than URTIs overall, and LRTIs were significantly more common (p < 0.001) in IVDAs than in the other-risk group. Tuberculosis (40%) and bacterial pneumonias (33%) comprised the majority of LRTIs among IVDAs, while Pneumocystis carinii pneumonia (40%) was the commonest LRTI in the other-risk group. Analysis of CD4 T-lymphocyte counts indicated that HIV-seropositive IVDAs are at greater risk of developing chest infections at higher CD4 counts than other-risk patients. The IVDAs were also found to have a much higher rate of co-infection with hepatitis C and B, which may be a factor accelerating the progression from HIV infection to AIDS. The mean time averaged for the two groups from known seroconversion to development of respiratory tract infection is only 1.37 years, which suggests HIV-infected patients are presenting late for treatment in Malaysia.

AIDS-Related Opportunistic Infections↗

PubMedDate not supplied

The primary culture of rat prostate basal cells.

The objective of this study was to identify the cells from rat prostate epithelium that attach and proliferate in primary culture. Minced ventral prostate was dissociated by DNAse/collagenase digestion, suspended in RPMI-1640 containing 10% fetal bovine serum, and subjected to Percoll centrifugation to separate the epithelial cells from stromal cells. With the use of lectins, it became possible to identify and monitor the fate of the dissociated epithelial cells held in suspension at 37 degrees C for several hours. In tissue sections of the rat prostate, Griffonia simplicifolia I-isolectin B4 (GSI-B4) specifically bound to basal cells, while Glycine maximus (soybean agglutinin [SBA]) was specific for secretory cells. Double staining with lectins and propidium iodide of dissociated cells revealed a preponderance of GSI-B4-positive live cells. The cells were plated in WAJC-404 medium supplemented with various factors, including insulin (5 ng/ml), transferrin (5 ng/ml), EGF (10 ng/ml), and bovine pituitary extract (30 microg/ml). Epithelial colonies that formed and proliferated from these cells also stained positively for GSI-B4 marker and for cytokeratins specific for basal cells as assessed by immunocytochemical staining. Proliferation was greater in cells grown on a collagen Type I matrix. These findings suggest that the epithelial cells that survived in suspension and proliferated in culture originated from basal cells of the rat prostate epithelium.

Animals↗