Biomedical subjects

C C Yu

Publications and source records attributed to C C Yu.

At least 55 records · Page 3Linked to original sources

PubMed1995

Pathological prognostic factors in the second British Stomach Cancer Group trial of adjuvant therapy in resectable gastric cancer.

The second British Stomach Cancer Group trial was a prospective randomised controlled trial of adjuvant radiotherapy or cytotoxic chemotherapy after gastrectomy for adenocarcinoma. It recruited between 1981 and 1986. No survival advantage has been demonstrated for the patients receiving either type of adjuvant therapy compared with those undergoing surgery alone. We report on 436 patients randomised into the trial together with 203 patients, who did not fulfil the trial criteria, referred to the trial. A univariate (log-rank) analysis of pathological factors obtained from the local referring centres showed that tumour size, macroscopic type, number os sites involved, depth of invasion, involvement of resection lines and lymph nodes and histological grade were significant determinants of survival. Histological review by two experienced histopathologists found that the Lauren classification and histological grade, but not the Ming classification, were significant prognostic factors. The degree of lymphocytic and eosinophilic infiltration and presence of dysplasia assessed by one of the pathologists showed a significant correlation with survival. However, inter-observer correlation for these histological parameters and grade was poor. Multivariate analysis identified only depth of invasion, resection line and nodal involvement as significant independent pathological variables influencing survival. This study confirms the need for expert preparation of the resected specimen to obtain the important information on depth of invasion and nodal status and also reveals some variation in histological assessment, particularly grading, in gastric carcinoma.

Adenocarcinoma↗

PubMed1995

Optimization of immunohistochemical staining of proliferating cells in paraffin sections of breast carcinoma using antibodies to proliferating cell nuclear antigen and the Ki-67 antigen.

Antibodies to proliferating cell nuclear antigen (PCNA) and the MIB-1 antibody to the Ki-67 antigen were titrated to optimize identification of proliferating cells in formalin-fixed paraffin-embedded tissue from a series of 40 human breast carcinomas. Cell culture studies have previously demonstrated that immunostaining for both PCNA and the Ki-67 antigen produces strong granular nuclear staining during S phase. PC10, other anti-PCNA antibodies (PC2, PC5, PC8 and 19F4) and MIB-1 were used at the minimum dilution which allowed a clear distinction between cells with strong and weak staining. With the anti-PCNA antibodies, nickel-cobalt enhancement of the reaction product was found to augment the granular nature of nuclear staining, corresponding more closely to patterns observed in cell culture studies. No enhancement was found to be necessary for MIB-1. The labelling indices of all these antibodies were compared with S phase fraction (SPF) obtained by DNA flow cytometry in the same cases. The PC10 labelling indices which included only strongly stained cells correlated well with SPF, but counting all strongly and weakly stained cells showed a poor correlation. With MIB-1, counting strongly stained as well as all stained cells produced labelling indices which correlated well with SPF, the former tending to be lower and the latter higher. None of the other anti-PCNA antibodies showed any advantage in application over PC10. Thus, PC10 and MIB-1, applied with care, can be correlated with S phase fraction in paraffin processed tissue sections of breast carcinomas.

Adenocarcinoma↗

PubMed1994

The role of C-reactive protein and erythrocyte sedimentation rate in the diagnosis of infected hydronephrosis and pyonephrosis.

Serum C-reactive protein levels and erythrocyte sedimentation rates were prospectively evaluated in 38 patients with dilated pyelocaliceal systems in an attempt to distinguish simple hydronephrosis from infected hydronephrosis and pyonephrosis. The clinical presentations of infected hydronephrosis and pyonephrosis were extremely variable, ranging from no constitutional complaints to urosepsis. Renal sonography detected only 6 of 16 patients with pyonephrosis (specificity 96%, sensitivity 38%, accuracy 72.5%). Using a cutoff value of 3.0 mg./dl. for C-reactive protein and 100 mm. per hour for erythrocyte sedimentation rate, the diagnostic accuracy of detecting infected hydronephrosis and pyonephrosis increased to 97%, with a specificity of 89% and sensitivity of 100%. Based on our experience, we believe that the serum C-reactive protein and erythrocyte sedimentation rate levels can be used as screening tests to distinguish pyonephrosis and infected hydronephrosis from simple, uncomplicated hydronephrosis.

Blood Sedimentation↗

PubMed1994

Posttransplant skin cancer: a possible role for p53 gene mutation but not for oncogenic human papillomaviruses.

BACKGROUND: Loss of p53 tumor suppressor function is a critical step in the development of diverse malignancies, including skin cancers in nonimmunosuppressed patients where UV-specific p53 gene mutations have been identified. In tumors associated with human papillomavirus (HPV), such as cervical carcinoma, p53 may be inactivated instead by binding to a viral oncoprotein. OBJECTIVE: Our purpose was to examine the hypothesis that HPV may play an analogous role in the development of posttransplant skin cancer. METHODS: p53 Immunoreactivity, suggestive of p53 gene mutation, was examined by immunocytochemistry. Oncogenic HPV DNA was detected by polymerase chain reaction. RESULTS: Comparable p53 immunoreactivity was seen in skin tumors from both transplant and nontransplant patients. HPV DNA was not demonstrated in any tumor specimen. CONCLUSION: Our data do not implicate oncogenic HPV in posttransplant skin cancer. p53 Gene mutation, rather than HPV-induced p53 degradation, may be more significant in the development of these tumors.

Basal Cell Carcinoma↗

PubMed1994

Effect of metabolic alterations on the accumulation of technetium-99m-labeled d,l-HMPAO in slices of rat cerebral cortex.

It is widely recognized that the distribution of technetium-99m-labeled d,l-hexamethylpropylene amine oxime (99mTc-HMPAO) in the brain is determined by the regional blood flow. However, other factors may affect this process including the metabolism of the brain tissue. To examine this possibility we studied the effects of metabolic alterations on 99mTc-HMPAO uptake in rat brain cortex slices, with concurrent measurement of oxygen consumption (QO2). 99mTc-HMPAO uptake was determined by incubating slices of rat cerebral cortex at 37 degrees C in Krebs-Ringer phosphate glucose medium containing 99mTc-HMPAO with and without test substances. Differential gradients for 99mTc activity between the tissue and the suspending medium (T/M ratio) were derived from the equation T/M[99mTc] = counts per gram of tissue/counts per milliliter of medium. The QO2 of the brain slices was measured using a biological oxygen monitor equipped with a polarographic oxygen probe. Inhibitors affecting oxidative phosphorylation caused parallel suppression of the T/M ratio and QO2. Agents that uncouple oxidation from phosphorylation increased the QO2 and decreased the T/M ratio. Incubation of slices at 22 degrees C depressed the T/M ratio and QO2. The presence of inhibitors of oxidative phosphorylation in the incubation medium increased the release of 99mTc activity from slices that had been prelabeled with 99mTc-HMPAO. These findings suggest that the altered metabolic status of the brain tissue modulates the kinetics and net accumulation of 99mTc-HMPAO at the cellular level by either depressing uptake, increasing back-diffusion, or both.

2,4-Dinitrophenol↗

PubMed1994

Intercomparison of activity size distributions of thoron progeny by alpha- and gamma-counting methods.

It is difficult to calibrate sampling devices using radon or thoron progeny or particles measuring 1-4 nm; therefore, an interlaboratory comparison is important to verify the performance of graded diffusion batteries for the activity size distributions of the "unattached" progeny. This paper describes the results of an interlaboratory comparison of 220Rn progeny size distributions using graded diffusion batteries by alpha- and gamma-counting methods with different data inversion schemes. Graded diffusion batteries designed at the Inhalation Toxicology Research Institute and at the Environmental Measurement Laboratory were used in the study. Screens and backup filters from the Environmental Measurement Laboratory-graded diffusion batteries were counted simultaneously in alpha counters for total alpha activities, and those of the Inhalation Toxicology Research Institute-graded diffusion batteries were counted in a gamma detector for gamma activities from 212Pb. Because of the different counting methods and data analysis procedures used, this interlaboratory study of 220Rn progeny allows a more rigorous way of testing instrument performance. 212Pb particles generated in well-controlled environments of oxygen, nitrogen, or oxygen with 1 ppm of nitrogen oxide were measured. In general, good agreement in activity size distributions was obtained from these two methods. Some differences observed in individual size spectra were attributable to the data inversion programs used in each laboratory. When the data were analyzed by the same computer program, most differences disappeared.

Alpha Particles↗

PubMed1994

Neutralization of thoron progeny in gases.

This paper reports charge neutralization phenomena of 212Pb particles in nitrogen or oxygen atmospheres with trace amounts of other gases. Newly produced thoron or radon progeny are positively charged, stable molecular clusters that are subsequently neutralized by several mechanisms. The charged clusters have a smaller diffusion coefficient than neutral clusters of the same size due to the interaction of the charge with the surrounding gas molecules. In this study, we have found that the diffusion coefficients of 212Pb in O2, N2, NH3/O2, NH3/N2, and C6H12/N2 (IPs between 15.58 and 9.8 eV) ranged between 0.015 and 0.030 cm2 s-1. In the case of C6H12/O2, NO2/O2, NO/O2, and dimethylamine/O2 (ionization potential between 9.8 and 8.23 eV), the diffusion coefficients have increased to between 0.046 and 0.69 cm2 s-1. These results are consistent with previous results of 218Po, indicating that charged progeny are neutralized by electron transfer from a gas molecule with a lower ionization potential than lead oxide. We estimate the ionization potential of lead oxide to range between 9.8 and 10.2 eV. 212Pb was also neutralized by an electron scavenging mechanism in NO2/nitrogen.

Air Pollution, Radioactive↗

PubMed1994

Patterns of capillaries in developing cerebral and cerebellar cortices of rats.

Patterns of capillaries in cerebral and cerebellar cortices were studied in developing rats. In cerebral cortex, the ventricular zone is well vascularized throughout the developmental period. The cell dense cortical plate is poorly vascularized, with capillary branches appearing in individual layers as they emerge from the cortical plate. In cerebellar cortex, the external granular layer appears devoid of capillary branches. Capillary branching appears first in the Purkinje and granule cell layers and later in the molecular layer. These results indicate: (1) an inside-out pattern of development of capillaries in both cortices, and (2) marked differences in vascularization of the proliferative zones for cerebral and cerebellar cortical neurons.

Aging↗

PubMed1994

Percutaneous nephroscopy in the diagnosis of renal pelvic filling defect: a report of two cases.

The major differential diagnosis of a radiolucent filling defect within the renal pelvis is among tumor, blood clot and radiolucent stone. In some cases, it is difficult to distinguish tumor from other benign lesions by imaging study. Two patients with renal pelvic filling defect were diagnosed by percutaneous nephroscopy, using the 27 Fr. rigid nephroscope (Olympus, Tokyo, Japan). Both patients got conclusive diagnosis by percutaneous nephroscopy; the morbidity was extremely minimal. The diagnostic percutaneous nephroscopy was a safe and effective procedure with minimal morbidity. For those patients without a conclusive diagnosis in noninvasive procedures, the percutaneous nephroscopy could be an alternative for flexible ureteroscopy, especially for the extremely tortuous ureters.

Aged↗

PubMed1993

Posttransplant cutaneous lymphoma.

BACKGROUND: Posttransplant lymphoma is closely associated with Epstein-Barr virus (EBV) infection and appears to have a predilection for extranodal sites. We describe four cases of primary cutaneous posttransplant lymphoma. OBJECTIVE: Our aim was to determine cell lineage and any possible association with EBV in each case of cutaneous lymphoma. METHODS: Tumor tissue was examined by light microscopy, immunohistochemistry, nonisotopic in situ hybridization and polymerase chain reaction. RESULTS: The data were consistent with a diagnosis of EBV-associated cutaneous B-cell lymphoma in three cases and cutaneous T-cell lymphoma not associated with EBV in one case. No patient with B-cell lymphoma had extracutaneous involvement during a mean follow-up of 3.9 years. The patient with cutaneous T-cell lymphoma died of cerebral involvement 9 months after initial presentation. CONCLUSION: These data suggest a possible role for EBV infection in the origin of cutaneous B-cell lymphoma in immunosuppressed patients.

Aged↗

PubMed1993

Analyses of radioactive aerosols to support accurate internal dose assessments at Chin-Shan nuclear power plant.

Studies of the physical and chemical properties of radioactive aerosols produced in different work environments were made at Chin-Shan nuclear power plant in Taiwan. These properties, including particle mass- and activity-size distributions, elemental and radionuclide compositions, and solubility lung class, are essential for the assessment of internal dose equivalents from the inhalation of radioactive aerosols. Several practices and environments studied include thermal arc cutting, grinding, sandblasting, and noble gas progeny. For physical analyses, cascade impactors, scanning electron microscopy with energy-dispersive x-ray analysis, inductively coupled plasma atomic emission spectrometry, and neutron activation analysis were applied. For chemical analyses, the solubility lung class was determined, in vitro, with the measurement of aerosol dissolution rates in simulated biological fluids. Results of these analyses were used to calculate the annual limit on intake, the derived air concentration, and committed dose equivalents for radiological protection against radioactive aerosols produced at Chin-Shan nuclear power plant.

Aerosols↗

PubMed1993

p53 immunoreactivity in human malignant melanoma and dysplastic naevi.

Expression of the tumour suppressor protein, p53, was determined in 77 cutaneous melanocytic lesions, and in five lymph node metastases from malignant melanoma, in an immunohistochemical study employing CM-1, an antiserum raised against recombinant human p53 protein. Because wild-type p53 protein is rapidly degraded in normal cells, p53 immunoreactivity suggests the presence of an abnormally stable p53 protein. This may occur through either post-translational mechanisms or gene mutation. A highly significant correlation was found between p53 immunoreactivity and malignancy in melanocytic lesions (P < 0.0001). Overall, p53 immunoreactivity was observed in 63% of tumour specimens examined, but not in benign melanocytic naevi, although occasional foci of weak nuclear p53 immunoreactivity were observed in a minority of dysplastic naevi and a solitary Spitz naevus. A significant correlation was also found between strong p53 immunoreactivity and malignant melanomas associated with a poor prognosis (P = 0.008). These data suggest an important role for p53 tumour suppressor protein in the biology of human cutaneous malignant melanoma.

Dysplastic Nevus Syndrome↗

PubMed1993

Patterns of immunohistochemical staining for proliferating cell nuclear antigen and p53 in benign and neoplastic human endometrium.

Immunohistochemical staining was carried out on a spectrum of normal, hyperplastic and malignant endometrial curettings, for proliferating cell nuclear antigen--PCNA (using the monoclonal antibody PC10) and for abnormally stabilized p53 (using the polyclonal antibody CM-1). The mean proportion of glandular epithelial cells showing PCNA immunoreactivity was significantly lower in atypical hyperplasia/intra-endometrial adenocarcinoma than in invasive adenocarcinoma, but the degree of overlap between the cases was such that this was not considered to be of diagnostic value. p53 immunoreactivity was detected in 47% of invasive adenocarcinomas and in a much smaller proportion of endometria showing simple hyperplasia and atypical hyperplasia, but staining was only focal in the last two conditions. The majority of p53-positive invasive adenocarcinomas had a large proportion of glandular epithelial cells expressing PCNA, but a significant number of p53-negative cases also had a high PC10 index. This suggests that, in endometrial neoplasia, there is not a simple relationship between abnormally stabilized p53 and PCNA expression.

Adenocarcinoma↗

PubMed1993

Uraemia with concomitant urothelial cancer.

We report our experience with 3 uraemic patients who were found to have transitional cell carcinoma of the renal pelvis, ureter and urinary bladder after undergoing haemodialysis for an average of 18 months (range 11-28). The underlying causes of renal failure were chronic glomerulonephritis or pyelonephritis. Bloody urethral discharge was the cardinal symptom. Because of anuria, it was often discovered at a late stage. In spite of their poor general condition and advanced stage, palliative surgical intervention was still performed. After a mean follow-up of 9 months, progression of disease was noted in 1 patient. The importance of regular follow-up in patients with end-stage renal disease for early detection of concomitant cancer cannot be over-emphasised. Uraemic patients with urothelial cancer should be treated in the same way as non-uraemic patients, since aggressive surgical intervention may improve their quality of life and prolong their survival.

Aged↗

PubMed1993

Long-term stone regrowth and recurrence rates after extracorporeal shock wave lithotripsy.

We reviewed 1055 patients with symptomatic urinary calculi treated by extracorporeal shock wave lithotripsy (ESWL) monotherapy to determine the long-term stone regrowth and recurrence rates as correlated with the pre-treatment stone burden, site and multiplicity. Long-term follow-up (mean 75.8 months) was available in 94 patients, representing 106 renal units. The recurrence of stone was defined as reappearance of stone on follow-up plain abdominal radiographs. The regrowth of stone was defined as stone regrowing larger than one-third of the original residual size. A stone-free rate of 53% was achieved. The overall stone regrowth and recurrence rates were 26 and 15% respectively. It was concluded that the stone recurrence rate after ESWL was not influenced significantly by the stone size or the multiplicity, but that the regrowth rate was. Stone recurrence and regrowth rates after ESWL were both influenced by the stone location.

Adult↗

PubMed1993

Proliferating cell nuclear antigen (PCNA) and nucleolar organiser regions in Hodgkin's disease: correlation with morphology.

AIM: To define the distribution of proliferating cell nuclear antigen (PCNA) and silver staining nucleolar organiser regions (AgNORs) in Hodgkin's disease. METHODS: PCNA was shown in a series of 34 cases of Hodgkin's disease using immunohistochemical methods. In a second series of 46 cases the AgNOR technique for interphase nucleolar organiser regions was studied. Both series comprised routinely fixed and processed paraffin wax sections of three main Rye subtypes. RESULTS: In all cases, regardless of Rye subtype, most Sternberg-Reed cells and mononuclear Hodgkin cells showed nuclear PCNA immunoreactivity and such cells had 15 or more AgNOR sites. The Hodgkin cells had, in general, about half the number of AgNORs seen in Sternberg-Reed variants. CONCLUSIONS: These data support the notion that Hodgkin's disease can be regarded as a high grade lymphoma, the large Hodgkin's and Sternberg-Reed cells being the (PCNA positive and AgNOR rich) neoplastic elements with high proliferative capacity. A smaller proportion of the associated cells also showed evidence of proliferation.

Antigens, Neoplasm↗

PubMed1993

Intradiverticular tumors of the bladder: surgical implications--an eleven-year review.

An 11-year review of all vesical diverticula and bladder tumors was undertaken. Fourteen patients were found to have primary neoplasms arising in the diverticula. The most common type was transitional cell. Hematuria was the most common presentation. Diagnosis is relatively difficult and treatment is not well defined. Lack or thinness of muscular layer of the diverticulum also potentiates early peridiverticular invasion and results in poor prognosis. Early diagnosis and adequate treatment are indicated.

Aged↗

PubMed1993

Increased epidermal cell proliferation in normal human skin in vivo following local administration of interferon-gamma.

Recombinant human interferon-gamma was administered intradermally (10 micrograms in 0.1 ml) to healthy adult human volunteers from day 1 to day 3, and epidermal cell proliferation was measured on whole skin biopsies at day 6. Three independent parameters were assessed, namely, a) epidermal keratin-16 expression, b) keratinocyte proliferating cell nuclear antigen expression, and c) keratinocyte silver nucleolar organizer region counts. Significantly increased scores for each parameter were observed after interferon-gamma injection (P < 0.01 in each case) compared to site-matched controls. Keratin-16 expression was confined to suprabasal epidermis, whereas proliferating cell nuclear antigen and silver nucleolar organizer region counts were particularly elevated in the basal epidermis. Taken together with previous findings, these studies indicate both proinflammatory and growth regulatory roles for interferon-gamma in human skin. These data are likely to be of particular importance to pathophysiological mechanisms of psoriasis and related cutaneous inflammatory diseases.

Adult↗