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C C Yu

Publications and source records attributed to C C Yu.

At least 73 records · Page 4Linked to original sources
PubMed1993

Update on proliferation-associated antibodies applicable to formalin-fixed paraffin-embedded tissue and their clinical applications.

This review provides an update on proliferation-associated antibodies applicable to immunohistochemical techniques in formalin-fixed paraffin-embedded tissue. New insights into proliferating cell nuclear antigen (PCNA) and antibodies to PCNA are presented. The characterization of the protein recognized by the Ki-67 antibody has enabled production of a new range of antibodies (monoclonal and polyclonal) which have immunostaining profiles similar to those of the original antibody. A new proliferation-associated antibody, KiS1, is described. The clinical applications of antibodies to PCNA in human material are summarized, and the limitations of these studies are discussed.

Animals↗
PubMed1993

Effect of intravenous clonidine on prevention of postepidural shivering.

The effects of intravenous clonidine, a central adrenergic alpha-2 agonist, on the incidence of shivering and hemodynamic changes after epidural anesthesia were assessed in patients undergoing extracorporeal shock wave lithotripsy (ESWL). Forty ASA class I or II patients were randomly assigned in a double-blind manner to one of two groups. Twenty patients received intravenous clonidine 150 micrograms/10 ml (clonidine group) and twenty patients received normal saline (control group) at 20 min before epidural administration of 1.5% lidocaine. Shivering was determined objectively by observing involuntary muscle activity. Arterial blood pressure, heart rate, respiratory rate and oxygen saturation were measured at 5-min intervals during the first 50 minutes following IV pretreatment. There was significant difference between clonidine and control groups in the incidence of shivering (5% vs. 55%, p = 0.002). Shivering began at an average of 16.8 +/- 9 min (range: 5-30 min) in control group and only one patient shivered at 18 min in clonidine group. The mean sensory level was T7 in both groups. There were no differences between the two groups in mean arterial pressure and respiratory rate, though there was a trend in reduction of MAP in clonidine group. Heart rate and oxygen saturation decreased slightly in clonidine group. The main adverse effect of clonidine pretreatment was drowsiness. In conclusion, intravenous clonidine 150 micrograms was effective in preventing shivering with minor hemodynamic changes in patients receiving epidural anesthesia.

Adult↗
PubMed1993

The effect of mannitol on antidiuretic and natriuretic actions of ADH in rats.

The effect of mannitol and glucose on antidiuretic and natriuretic actions of ADH was investigated in water-loaded, male Sprague-Dawley rats anesthetized with sodium pentobarbital (5 mg/100g). Water diuresis was induced and sustained by continuous intravenous perfusion of hypotonic solution containing 0.3% NaCl, 1.67% glucose, 1.2% ethanol and sufficient inulin at a constant rate 150 microliters/min. Arginine vasopressin at a single dose 0.1 ng/100g was tested twice in the phase of water diuresis and in the phase of water diuresis plus mannitol osmotic diuresis. Urine samples were collected at ten-minute intervals. Three doses of mannitol (5.18, 3.63, 1.81 mumol/min/100g) were given into the right renal artery in three groups of experimental rats, respectively. Administration of mannitol did not alter renal inulin clearance but increased urine flow and excretion of sodium from experimental kidney. Our findings show that mannitol reduced antidiuretic response to ADH in the experimental kidney. This reduction was related to intraarterial mannitol doses. Local administration of mannitol increased natriuretic action of ADH in the experimental kidney. However, a small dose (1.81 mumol/min/100g) of mannitol did not increase natriuretic action of ADH. Saline and glucose (5.23 mumol/min/100g) were also infused intra-arterially to replace mannitol. The effect of saline on antidiuretic and natriuretic responses to ADH was found to be insignificant. Glucose reduced antidiuretic response to ADH as mannitol did but failed to alter natriuretic response to ADH as saline did. We conclude that mannitol does positively affect antidiuretic and natriuretic actions of ADH. Glucose has similar effect but much less than mannitol.

Animals↗
PubMed1993

[Urethral stent: a preliminary report].

Despite recent progress in endoscopic and reconstructive urology, the management of urethral strictures remains a challenge to all urologists. Repeated urethral dilation and endoscopic optic urethrotomy may cure the short urethral strictures, but they are frustrating and time-consuming both for the patient and the physician. Intermittent self-catheterization, which is suggested to maintain a satisfactory urethral lumen, is not well accepted by many patients. Urethroplasty procedure usually is successful in the treatment of traumatic strictures but it requires surgical skills and expertise to which few patients have easy access. We describe a new treatment for urethral strictures with the use of the urethral Wallstent, which is self-expanding and made of stainless steel, in 4 males with difficult urethral stricture (3 recurrent strictures and 1 fresh case). The results are satisfactory with less complications. It is a simple, safe and effective alternative to other surgical interventions in patients with intractable urethral stricture.

Adult↗
PubMed1992

A comparison of proliferating cell nuclear antigen (PCNA) immunostaining, nucleolar organizer region (AgNOR) staining, and histological grading in gastrointestinal stromal tumours.

Gastrointestinal stromal tumours are lesions in which it is difficult to predict clinical outcome from the histological appearances. Sixty cases were studied using three different methods of assessing aspects of cellular proliferation; these were (i) immunostaining for proliferating cell nuclear antigen (PCNA), (ii) interphase nucleolar organizer region staining (AgNORs), and (iii) a histological grading system based on mitotic counts. Both PCNA immunostaining and AgNOR counts were found to correlate well with histological grading and all three methods independently showed good correlations with survival. This suggests that these proliferation-associated markers may be used as additional features to support histological grading in this relatively uncommon group of tumours.

Antigens, Neoplasm↗
PubMed1992

The assessment of cellular proliferation by immunohistochemistry: a review of currently available methods and their applications.

Immunohistochemical methods using antibodies to cell cycle-related antigens may be used as a means of assessing various aspects of proliferation in tissue, and have the important advantage of preserving the spatial orientation of proliferating cells in histological sections. Currently, the most widely available antibodies for this purpose are antibodies to bromodeoxyuridine (BrdU), Ki67 and antibodies to proliferating cell nuclear antigen (PCNA). BrdU is a thymidine analogue incorporated during the S phase of the cell cycle, which can be introduced by 'in vitro' incubation, and monoclonal antibodies are available to display its localization. Ki67 demonstrates a nuclear antigen expressed in all phases of the cell cycle, except G0 and early G1, but can only be applied to frozen tissue. PCNA is a nuclear antigen which is essential for DNA synthesis, two commercially available antibodies to PCNA work in paraffin-embedded tissue, but may have different staining characteristics under different conditions of fixation. The main advantages and disadvantages of these different techniques are discussed, together with their main applications to date.

Antibodies, Monoclonal↗
PubMed1992

Aberrant expression of p53 tumour-suppressor protein in non-melanoma skin cancer.

Expression of the cellular p53 tumour-suppressor protein was examined in 78 epidermal tumours, including basal and squamous cell carcinomas, keratoacanthomas, solar keratoses, Bowen's disease and viral warts. An immunohistochemical study was employed using the antibody CM-1, raised against recombinant human p53 protein. Positive staining for p53, not detectable in normal cells because wild-type p53 is rapidly degraded, reflects abnormal stabilization of p53 protein, and in many cases suggests p53 gene mutation. p53 immunoreactivity was not observed in normal skin or in viral warts. In contrast, positive staining for CM-1 was seen throughout the tumour in the majority of basal and squamous cell carcinomas and in Bowen's disease. Immunoreactivity to p53 was also observed in the majority of keratoacanthomas and solar keratoses, but was confirmed to areas of dysplastic basal epithelium. This study demonstrates that accumulation of p53 protein, suggestive in many cases of p53 gene mutation and hence loss of tumour-suppressor function, may occur as an important early step in the development of diverse epidermal cancers.

Bowen's Disease↗
PubMed1992

Simultaneous bilateral adrenal metastases from renal cell carcinoma. Surgical implications and review of the literature.

We report a case of left-side renal cell carcinoma with contemporary bilateral adrenal involvement discovered preoperatively with computerized tomography and other imaging techniques. Surgical treatment consisted of radical nephrectomy with a nearly total contralateral adrenalectomy and the unroofing of a lower pole renal cyst. Postoperative cortisone acetate replacement was instituted. The surgical implications of renal cell carcinoma with metastasis are also discussed.

Adrenal Gland Neoplasms↗
PubMed1992

Neonatal status in cesarean section under epidural anesthesia with supplementary oxygen.

Simple O2 mask has been used in patient under regional anesthesia for increasing the FiO2, especially in the aged and the pregnant. The relationships between maternal FiO2 and umbilical arterial (UA) and venous (UV) PO2, PCO2, pH, and neonatal Apgar score were studied in 45 patients receiving Cesarean section under epidural anesthesia. 2% xylocaine 18-20 ml with adrenaline 1:200,000 was used to attain the sensory level of T-4. Patients were allocated randomly into three groups. Group I, acting as a control group, breath only room air during the course of anesthesia. Group II was breathing through a simple face mask with an oxygen inflow of 6L/min. Group III was breathing oxygen with a flow rate of 10L/min through a simple face mask. UA and UV blood samples were collected separately at the time of delivery for blood gas analysis. The 1-min, and 5-min Apgar scores were recorded also. Mean values of the UA blood samples for the 3 groups (Gp. I, Gp. II and Gp. III respectively) were: PO2--16.50 mmHg, 20.20 mmHg and 19.50 mmHg; PCO2--49.20 mmHg, 48.10 mmHg and 50.3 mmHg; pH--7.31, 7.30 and 7.30. Mean values of the UV blood samples for the 3 groups (Gp. I, Gp. II and Gp. III respectively) were: PO2--28.6 mmHg, 36.9 mmHg and 36.5 mmHg; PCO2--38.20 mmHg, 38.80 mmHg and 40.40 mmHg; pH--7.36, 7.36 and 7.34. There was a significant increase in UA and UV PO2 when using a simple O2 mask (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Interleukin 4 expressed in situ selectively alters thymocyte development.

Using a transgenic mouse model we show that increased intrathymic expression of interleukin 4 (IL-4) significantly perturbs the development of thymocytes. Transgenic double-positive (CD4+CD8+) thymocytes, which are present in dramatically reduced numbers, exhibit increased T cell receptor (TCR) expression and increased mobilization of calcium mediated by these receptors. In contrast, transgenic single-positive (CD4+CD8- and CD4-CD8+) thymocytes and peripheral T cells exhibit decreased TCR-mediated calcium mobilization. The development of CD4-CD8+ thymocytes is significantly perturbed by IL-4 expressed in vivo; only peripheral CD4+ T cells are found in significant numbers in transgenic mice, while CD4-CD8+ thymocytes are present in increased numbers, apparently because of their failure to emigrate to the periphery. In contrast to these selective effects on T cell development, no significant differences in the numbers of B cells or mast cells, or in the plasma levels of IgE and IgG1 are observed between transgenic and control mice. These observations suggest that IL-4 in vivo exerts its major effects locally rather than systemically, even when its expression is constitutively increased.

Animals↗
PubMed1991

Effect of endothelin-1 on the vascular smooth muscle cell cycle.

Rabbit vascular smooth muscle cells were cultured in various concentrations of endothelin-1 (ET-1) at 37 degrees C for 24 h. The vascular smooth muscle cell cycle distribution was determined by flow cytometry according to DNA content. In the control group, the mitotically active phase (S + G2 + M phase) of vascular smooth muscle cells was 11.94%. In ET-1-cultured smooth muscle cells, the mitotically active phase was 11.69% at a concentration of 1 pM ET-1, whereas the mitotically active phases were 18.98 and 26.91% at concentrations of 0.1 and 10 nM ET-1, respectively. The findings show that ET-1 significantly increased mitotic activity of cultured vascular smooth muscle cells.

Animals↗
PubMed1991

Haemangiopericytomas: the prognostic value of immunohistochemical staining with a monoclonal antibody to proliferating cell nuclear antigen (PCNA).

Forty-two cases of haemangiopericytoma were studied retrospectively using immunohistochemical staining with PC10, a monoclonal antibody to PCNA. The percentage of tumour cells with positive staining for PCNA was found to correlate well with histological grading. Clinical follow-up data were available in 25 adults and showed no known deaths in 11 cases with a low proportion (less than 14%) of positive cells. Out of 14 cases with a high number (greater than or equal to 14%) of positive cells, seven patients are known to have died, two had metastases, and in a further two there have been multiple recurrences of tumour. DNA flow cytometry was performed on 26 cases but this showed no correlation with PC10 staining or clinical outcome. Staining with PC10 may be of particular value in the identification of patients at greatest risk of rapid tumour metastasis and early death.

Adolescent↗
PubMed1991

Serum iron as a tumor marker in renal cell carcinoma.

To evaluate the feasibility of using serum iron as a tumor marker for renal cell carcinoma, a retrospective review of serum iron, hemoglobin, hematocrit, mean corpuscular volume and pathology in patients with renal cell carcinoma was carried out. From January 1985 to December 1989, preoperative serum iron was obtained in 82 patients; 27 had stage I, 5 stage II, 23 stage III and 27 had stage IV disease. The serum iron levels (micrograms/dl) were 81.6 +/- 33.2 in stage I, 57.8 +/- 18.9 in stage II, 59.6 +/- 34.6 in stage III and 45.6 +/- 32.7 in stage IV disease, which were significantly lower as compared with the data (114.6 +/- 38.9) of a control group. Postoperative serum iron levels were available in 31 patients following nephrectomy and all showed an increase as compared with preoperative data except 2: 1 with recurrence and the other with progression of disease. It was concluded that the serum iron level may be used as a useful tumor marker in staging and follow-up of renal cell carcinoma.

Biomarkers, Tumor↗
PubMed1991

Cellular and molecular mechanisms for reduced interleukin 4 and interferon-gamma production by neonatal T cells.

The mechanisms by which T lymphocytes acquire the capacity to produce interleukin 4 (IL-4) and other lymphokines during intrathymic and extrathymic development are poorly understood. To gain insight into this process, we determined the capacity of human neonatal and adult T lineage cell populations to produce IL-4 after polyclonal activation. IL-2 and interferon-gamma (IFN-gamma) production were studied in parallel, since their production by neonatal T cells is known to be similar or diminished, respectively, compared to adult T cells. Production of IL-4 by neonatal CD4+ T cells and IFN-gamma by neonatal CD4+ and CD8+ T cells was markedly lower compared with analogous adult cell populations, whereas IL-2 production was similar. Transcription of IL-4, as determined by nuclear run-on assays, and IL-4 mRNA-containing cells, as determined by in situ hybridization, were undetectable in neonatal T cells, whereas both were detectable in adult T cells. IFN-gamma transcription and IFN-gamma mRNA-containing cells were reduced in neonatal T cells compared with adult T cells. Reduced lymphokine production by neonatal T cells correlated with their lack of a CD45R- (putative memory T cell) population; cells with this surface phenotype comprised 30-40% of the adult CD4+ T cells and were highly enriched for IL-4 and IFN-gamma, but not IL-2 production. IL-4, IFN-gamma, and IL-2 mRNA expression by neonatal CD4+CD8- thymocytes was similar to that found in circulating neonatal CD4+ T cells. Taken together, these findings suggest that the extrathymic generation of memory T cells during postnatal life may result in an increased capacity for IL-4 and IFN-gamma gene expression. In addition, IFN-gamma and IL-2 mRNA were significantly more abundant than IL-4 mRNA in activated neonatal CD4+CD8- thymocytes and CD4+ T cells, as well as adult CD4+ CD45R- T cells. Therefore, the capacity of T lineage cells to express the IL-4 gene may be more restricted compared to other lymphokine genes beginning in intrathymic development. This restricted capacity appears to persist during postnatal extrathymic maturation of T cells.

Adult↗
PubMed1990

Proliferating cell nuclear antigen (PCNA) immunolocalization in paraffin sections: an index of cell proliferation with evidence of deregulated expression in some neoplasms.

Proliferating cell nuclear antigen (PCNA) is a 36 kD nuclear protein associated with the cell cycle. A monoclonal antibody, PC10, that recognizes a fixation and processing resistant epitope has been used to investigate its tissue distribution. Nuclear PCNA immunoreactivity is found in the proliferative compartment of normal tissues. PCNA immunoreactivity is induced in lectin stimulated peripheral blood mononuclear cells in parallel with bromodeoxyuridine incorporation and the number of cells with PCNA immunoreactivity is reduced by induction of differentiation in HL60 cells. In non-Hodgkin's lymphomas a linear relation between Ki67 and PCNA staining was demonstrated. These data suggest that in normal tissues and lymphoid neoplasms, PCNA immunolocalization can be used as an index of cell proliferation. However, in some forms of neoplasia, including breast and gastric cancer and in vitro cell lines, the simple relation between PCNA expression and cell proliferation is lost. In some breast and pancreatic tumours there is apparent deregulation of PCNA with increased expression in tissues adjacent to the tumours. The over-expression in some tumours and in adjacent morphologically normal tissue may represent autocrine or paracrine growth factor influence on PCNA gene expression.

Adult↗