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Biomedical subjects

P Cao

Publications and source records attributed to P Cao.

At least 73 records · Page 4Linked to original sources
PubMed1997

Early occurrence and prognostic significance of p53 alteration in primary carcinoma of the fallopian tube.

The pathogenesis of primary carcinoma of the fallopian tube (PCFT) is poorly understood. Tumor suppressor p53 gene alterations are common in human malignancies, but their role in the tumorigenesis and survival of PCFT is undefined. The objectives of this study were to define the occurrence and prognostic role of p53 alteration in PCFT and to examine the efficiency of immunohistochemistry (IHC) in detecting p53 alteration in PCFT. Fifty-two PCFT and 10 normal fallopian tubes were examined for p53 alteration by IHC and polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP). The Kaplan-Meier method was used to derive the survival function, while the log-rank test was used to compare curves for two or more groups. Other patients' characteristics were analyzed by two-tailed Fisher's exact tests. IHC correlated well with PCR-SSCP with 100% sensitivity and 83.3% specificity for detecting p53 alteration in this study. Thirty-one of 52 (57%) PCFT showed p53 alteration. Alteration of p53 occurred in all stages of PCFT with a similar incidence in carcinoma in situ and late-stage disease. Alteration of p53 was related to tumor histologic type. Significant survival difference was noted between advanced and early clinical stages but no such difference was identified among different tumor grades. Compared to the p53-nonaltered group, the presence of p53 alteration in PCFT was related to significantly decreased patient survival (RR = 6.8, 95% CI = 2.9-16.2) in multivariate analysis. In the subgroup of patients with residual tumor after surgery, those with p53-altered tumors had a significantly decreased survival compared to those with p53-nonaltered group (RR = 7.4, 95% CI = 1.9-28.2). Alteration of p53 is common and IHC is an efficient method to detect p53 alteration in PCFT. Shorter survival is associated with p53 alteration which is an independent marker for the disease in this study. Alteration of p53 may be an early event in tubal tumorigenesis and may play an important role in the development of PCFT. Whether detection of p53 alteration may serve as an indicator of high-risk patients for whom more aggressive adjuvant chemotherapy may be considered needs to be explored in the future.

Aged↗
PubMed1997

Transcranial Doppler monitoring during carotid endarterectomy: is it appropriate for selecting patients in need of a shunt?

PURPOSE: This report summarizes our experience in evaluating a series of 168 patients who underwent a total of 175 carotid endarterectomy procedures under local anesthesia. Patients were monitored by stump pressure (SP) measurement and transcranial Doppler scanning (TCD). The need for shunting was compared between SP/TCD flow velocity reduction and the awake response (gold standard). METHODS: The study cohort represented 56% of all the carotid patients treated during the study period. Clamping ischemia was defined as the appearance of focal deficit (focal ischemia) or unconsciousness (global deficit) on carotid clamping. In the case of clamping ischemia, a shunt was inserted. To define the optimal value of SP and TCD flow velocity that is able to discriminate patients with clamping ischemia, a receiver operator characteristic (ROC) curve was constructed. Sensitivity and specificity tests, together with negative and positive predictive values (NPV and PPV), were calculated. Cutoff values were defined as the ROC curve values that correlated the highest sensitivity with the highest specificity for both SP and TCD. RESULTS: Clamping ischemia was present in 18 procedures (10%) in which a shunt was used. No perioperative deaths were recorded. Major perioperative morbidity occurred in one patient (0.6%). Two nondisabling strokes were also recorded (1.8% overall rate of neurologic morbidity). Cutoff values for both SP and TCD, using the ROC curve, were < or = 50 mm Hg and > or = 70% flow velocity reduction from baseline, respectively. SP values of < or = 50 mm Hg or less showed a sensitivity of 100%, a specificity of 83%, a PPV of 40%, and an NPV of 100%. TCD flow monitoring (> or = 70% flow reduction) revealed a lower sensitivity (83%) but a greater ability to avoid false positive results (96% specificity), resulting in increased PPV (71%) and NPV (98%). Combining SP and TCD failed to provide better results in terms of specificity (81%) and PPV (38%). CONCLUSIONS: SP measurement using a 50 mm Hg cutoff appears to be a reliable predictor of clamping ischemia but requires the use of a shunt in 17% of the patients who would otherwise not require this procedure. In contrast, TCD has greater specificity but is associated with a lower sensitivity, with 17% false negative results. In our experience, both SP and TCD show limitations, as they overestimate or underestimate carotid endarterectomy procedures in need of a shunt. We believe that sensitivity is more important than specificity in carotid endarterectomy, and thus conclude that TCD flow velocity measurement is not an optimal method for detecting clamping ischemia.

Aged↗
PubMed1997

Eversion versus conventional carotid endarterectomy: a prospective study.

OBJECTIVES: To analyse comparatively eversion and conventional CEA for later association with restenosis, perioperative stroke/death and ipsilateral cerebrovascular events (early, late, disabling and non-disabling). DESIGN: Prospective non-randomised clinical study. MATERIALS AND METHODS: A total of 469 patients underwent 514 procedures; 274 (53%) eversion CEA and 240 (47%) conventional CEA. Perioperative monitoring was carried out by clinical evaluation under local anaesthesia or by transcranial Doppler under general anaesthesia. Follow-up was carried out by clinical evaluation and Duplex scanning. RESULTS: Clamping time was significantly shorter in the eversion group (25.5 +/- 7.4 vs. 28.3 +/- 10.1 min; p = 0.0001; CI delta 4.40/1.12). The perioperative disabling stroke/death rate was 0.7% for eversion vs. 1.2% for conventional CEA, p = 0.6; odds ratio (OR), 0.58. There were two early carotid occlusions (within 30 days) in both groups. According to life-table analysis, after 3 years the probability of > 50% carotid restenosis was significantly lower in the eversion group (2.2% vs. 6.9%, p = 0.03; relative risk reduction 67%). There were no significant differences between the two groups relative to new cerebrovascular events (92% in both groups, p = 0.6). Using multivariate analysis (Cox regression), eversion CEA, and to a lesser extent standard CEA with patch, appeared to protect the vessel from restenosis. CONCLUSIONS: The eversion technique was associated with reduced clamping time and probability of restenosis. However, because of the nature of a non-randomised study, the present analysis should be confirmed by a multicentre randomised trial.

Aged↗
PubMed1997

High-level genetic diversity in the vapD chromosomal region of Helicobacter pylori.

Helicobacter pylori isolates from different patients are characterized by diversity in the nucleotide sequences of individual genes, variation in genome size, and variation in gene order. Genetic diversity is particularly striking in vacuolating cytotoxin (vacA) alleles. In this study, five open reading frames (ORFs) were identified within a 4.2-kb region downstream from vacA in H. pylori 60190. One of these ORFs was closely related to the virulence-associated protein D (vapD) gene of Dichelobacter nodosus (64.9% nucleotide identity). A probe derived from vapD of H. pylori 60190 hybridized with only 19 (61.3%) of 31 H. pylori strains tested. Sequence analysis of the vapD region in vapD-negative H. pylori strains revealed that there were two different families of approximately 0.5-kb DNA segments, which were both unrelated to vapD. The presence of vapD was not associated with any specific family of vacA alleles. These findings are consistent with a recombinational population structure for H. pylori.

Alleles↗
PubMed1997

[Research on omni-directional ultrasonic imaging].

In this paper, an omni-direction M-mode ultrasonic imaging method is introduced, in which M-mode sample line can rotate and move freely. In this way the measurement of parameters such as amplitude and speed of movement of organs can be conducted in any position or direction. We analyzed the sources of errors of the method and the way to overcome them.

Echocardiography↗
PubMed1997

[Studies on purging leukemic cells by photosensitizer PSD-007 laser photoradiation in vitro].

The sensitivity to photosensitization mediated by the hematoporphyrin photosensitizer PSD-007 of acute promyelocytic leukemic cell line (HL-60) was compared with normal human hemopoietic progenitor cells. The results showed that the leukemic cells were more sensitive. After being treated with 10 micrograms.ml-1 PSD-007 followed by 2J.cm-2 copper vapor laser light irradiation, the clonogenic leukemic (HL-60) cells were reduced 98%, but the survival rate of human granulocyte-macrophage colony-forming units (CFU-GM) was 40 +/- 8%. Mixing of normal human marrow cells with leukemic (HL-60) cells (ratio 100:1) did not interfere with elimination of tumor cells. The ultrastructure changes of HL-60 cells treated by laser photoradiation was observed under the trans-electronic microscope. The mitochondria, endoplasmic reticulum and cell membrane were involved. This means that the cell biomembrane is the main target to be attacked. It is considered that PSD-007-laser photoradiation therapy is efficient for killing leukemic cells.

Adult↗
PubMed1996

Surgical care in octogenarians.

The general surgical profile of octogenarians compared with that of younger patients, and risk factors predictive of operative mortality and morbidity, were determined retrospectively using a computer database for all patients admitted between 1989 and 1993. There were 934 admissions of octogenarians and surgery was performed in 447 cases (47.9 percent). The admission rate of patients over 80 years of age increased during the 5-year period from 4.6 to 9.0 per cent, and was significantly higher than that of geriatric patients aged 65-79 years (P < 0.01). Emergency admissions (63.6 percent) and operations (42.3 percent) were more frequent in patients aged over 80 years (P < 0.01); emergency operations increased during the 5 years from 38 to 59 percent. Altogether, 83 deaths and 171 complications were recorded. The mortality rate of octogenarians was greater than that of younger patients (P < 0.01). Postoperative mortality and morbidity rates were 10.1 and 32.2 percent respectively. After multiple logistic regression analysis with stepwise backward elimination, an American Society of Anesthesiologists score of II-V (P < 0.01), the presence of two associated diseases (P < 0.01) and laparotomy procedures (P < 0.03) appeared to be independent risk factors for postoperative mortality and morbidity.

Aged↗
PubMed1996

p53 overexpression and bcl-2 persistence in endometrial carcinoma: comparison of papillary serous and endometrioid subtypes.

Forty-two cases, including 21 uterine papillary serous carcinomas (UPSC) and 21 age-, nuclear-grade-, and clinical-stage-matched uterine endometrioid carcinomas (UEC), were studied immunohistochemically for p53 and bcl-2 in archival paraffin-embedded tissue. Compared to UEC (28.6% positive), UPSC (71.4% positive) had a significantly higher frequency of p53 overexpression (P = 0.005); furthermore, in a clinical-stage-matched fashion, a higher frequency of p53 overexpression was found in early-stage cases (P = 0.032), but not in late-stage cases. In a nuclear-grade-matched comparison, no statistical difference in p53 overexpression was identified between the two subtypes, although UPSC had stronger p53 immunoreactivity than UEC. Of UPSC, no difference in p53 overexpression was detected between tumors of early and late stages; additionally, in 5 cases, there was an abrupt transition from nonstaining morphologically benign glands to uniformly positive p53 nuclear staining in regions of intraepithelial carcinoma. Conversely, in UEC, there was a significant difference in p53 immunostaining between tumors of early and late stages (P = 0.01); no case had an abrupt transition for p53 immunostaining. For bcl-2 immunostaining, UEC had a significantly higher immunohistochemical staining score than did UPSC (P = 0.0002). In general, the staining intensity of bcl-2 diminished progressively from proliferative phase and hyperplastic endometrium to UEC and then to UPSC, with 3 of 21 (14.3%) UPSC being negative. These results suggest that p53 alteration may be an early event in the development of UPSC and may be related to its clinical aggressiveness, while it is a late event in UEC. Early detection of p53 nuclear accumulation may help to identify precursor lesions of UPSC. bcl-2 persistence is frequently associated with endometrial carcinoma, and failure to inactivate bcl-2 expression probably is related to the development of endometrial carcinoma.

Aged↗
PubMed1996

Comparison of target organ damage in renovascular and essential hypertension.

In many reports, the prevalence of target organ damage in renovascular hypertension (RVH) appears to be higher than in essential hypertension (EH). Since in most studies the renal artery stenosis is part of a diffuse atherosclerotic disease, it is not known whether these complications are due to RVH itself or to the vascular disease. We have undertaken a case control study of 92 patients divided into two groups (46 in each), one with RVH and the other with EH and abdominal aortic aneurysm, with a comparable degree of diffuse atherosclerotic vascular disease. The vascular state of the extracranial carotid arteries and abdominal and inferior limb districts was investigated with angiography and sonography. The prevalence of left ventricular hypertrophy (LVH) and ischemic heart disease (IHD) were assessed by electrocardiography. Serum creatinine and urinary protein excretion were employed in the renal evaluation. While the analysis of the results confirmed an even diffusion of atherosclerotic vascular disease between the two groups, a significant difference was found in the prevalence of heart and renal damage. LVH was present in 32.6% of RVH patients versus 10.8% in EH (P = .02). Serum creatinine > 1.4 mg/dL was found in 50% of RVH and in 23.9% of EH, (P = .01). The prevalence of proteinuria in RVH was also higher although not reaching the statistical significance. The results suggest that, in patients with comparable degrees of atherosclerotic vascular disease, RVH is responsible for the higher prevalence of target organ damage in this condition compared to those with EH.

Aged↗
PubMed1996

Computerised tomography findings as a risk factor in carotid endarterectomy: early and late results.

OBJECTIVES: To evaluate whether preoperative CT evidence of brain infarction is associated with an increased risk of early and late stroke and death in patients undergoing CEA. DESIGN: Retrospective clinical study. MATERIALS AND METHODS: We evaluated 844 CT scanning records from 893 patients undergoing CEA from 1986-1994: 43% (367) CT positive for cerebral infarction and 57% (477) negative. Univariate and multivariate analysis was performed for risk factors and preoperative symptoms in patients with positive and negative CT scans, and Kaplan Meier survival curves for late events. RESULTS: A positive CT was significantly more frequent in males vs. females (p < 0.0001; O.R. 2.52; C.I. 1.73-3.73), diabetics vs. non-diabetics (p = 0.03; O.R. 1.52; C.I. 1.03-2.26), symptomatics vs. asymptomatics (p < 0.001; O.R. 2; C.I. 1.93-3.53) and contralateral occlusion vs. patency (p < 0.001; O.R. 2; C.I. 1.30-3.10). The perioperative disabling stroke/ death rate was higher in patients with a positive CT (p = 0.002; O.R. 6.27; C.I. 1.73-34.20); in asymptomatic patients this difference was striking (5 patients vs. O, p = 0.0002). Multiple logistic regression analysis for risk factors, CT findings, symptoms preceding surgery, and congruity of brain infarction confirmed a significantly higher incidence of perioperative stroke/death rate (p = 0.003; O.R. 6.37; C.I. 5.12-7.63) and early and late stroke (p = 0.02; O.R. 1.95; C.I. 1.38-2.53) and death (p = 0.0005; O.R. 2.38; C.I. 1.89-2.88) in patients with brain lesions. After 7 years, the survival rate (p = 0.0009) and stroke-free interval (p = 0.003) were lower in patients with a positive CT. After 5 years, in asymptomatic patients the survival rate (p = 0.003) and stroke-free interval (p = 0.01) were lower in the positive CT group. CONCLUSIONS: A positive CT finding, regardless of congruity of the lesion, should be regarded as an indicator of an increased risk of stroke and death in patients scheduled for carotid surgery, especially in those with asymptomatic stenosis.

Adult↗
PubMed1996

[Study on changes of visual fatigue index during prolonged visual display terminal operation].

25 Arabic numerals (0-9) lined in a row were displayed with 4 different patterns on CRT. The subjects were asked to find out the one missed numeral in the row and to press the key corresponding to the numeral. The work lasted for 3h. Longitudino-Kinetic visual acuity was measured before and at 30, 60, 80, 100, 120, 150, 180 minutes during the work. The results showed that the Longitudino-Kinetic visual acuity dropped with working time and recovered after work quickly at first and then slowly.

Asthenopia↗
PubMed1996

[Purification and properties of polysaccharide PPIII from Sterculia lychnophora Hance].

Polysaccharide PP III was isolated and purified from aqueous extract of the seeds of Sterculia lychnophora. It is composed of galactose, arabinose and rhamnose, the molar ratio being 1 : 1.67 : 1.01 and molecular weight 162200. Rhamnoses in the main chain are linked by alpha-(1-->3) glycoside linkage. PP III C is its major fragment, and is composed of galactose and rhamnose with a molar ratio of 1 : 2. 78 and MW 62500.

Arabinose↗
PubMed1995

Mosaicism in vacuolating cytotoxin alleles of Helicobacter pylori. Association of specific vacA types with cytotoxin production and peptic ulceration.

Approximately 50% of Helicobacter pylori strains produce a cytotoxin, encoded by vacA, that induces vacuolation of eukaryotic cells. Analysis of a clinically isolated tox- strain (Tx30a) indicated secretion of a 93-kDa product from a 3933-base pair vacA open reading frame. Characterization of 59 different H. pylori isolates indicated the existence of three different families of vacA signal sequences (s1a, s1b, and s2) and two different families of middle-region alleles (m1 and m2). All possible combinations of these vacA regions were identified, with the exception of s2/m1 (p < 0.001); this mosaic organization implies that recombination has occurred in vivo between vacA alleles. Type s1/m1 strains produced a higher level of cytotoxin activity in vitro than type s1/m2 strains; none of 19 type s2/m2 strains produced detectable cytotoxin activity. The presence of cagA (cytotoxin-associated gene A) was closely associated with the presence of vacA signal sequence type s1 (p < 0.001). Among patients with past or present peptic ulceration, 21 (91%) of 23 harbored type s1 strains compared with 16 (48%) of 33 patients without peptic ulcers; only 2 (10%) of 19 subjects harboring type s2 strains had past or present peptic ulcers (p < 0.005). Thus, specific vacA genotypes of H. pylori strains are associated with the level of in vitro cytotoxin activity as well as clinical consequences.

Adult↗
PubMed1995

Carotid endarterectomy contralateral to an occluded carotid artery: a retrospective case-control study.

OBJECTIVES: To analyse whether contralateral occlusion represents an additional perioperative risk factor in carotid endarterectomy (CEA), and whether long-term survival after surgery in patients with contralateral occlusion differs from that of patients without. DESIGN: Retrospective clinical study. SETTING: Vascular Surgery Unit, Department of Surgery, University of Perugia, Perugia, Italy. MATERIALS: Fifty-five patients with carotid stenosis and contralateral occlusion undergoing CEA (Group 1) were compared with 110 patients (Group II), without contralateral occlusion selected from a cohort of 367 patients with a patent contralateral artery, matched for gender, age and ipsilateral symptoms. CHIEF OUTCOME MEASURES: Perioperative stroke/death rate at 30 days and minor complications in Group I vs. Group II over a mean follow-up of 38 months. MAIN RESULTS: The perioperative stroke/death rate at 30 days was 0% in Group I and 2.7% in Group II (p = 0.6) while minor complications amounted to 11% in Group I and 5% in Group II (p = 0.2). Survival rates of patients free from stroke, using Kaplan Meier curves, were 79.4% in Group I and 83.3% in Group II (p = 0.4); stroke free rates were 92.8% and 94.3% in Groups I and II, respectively. The incidence of late stroke, fatal or not, in patients who had undergone CEA with contralateral obstruction was the same as in similarly operated patients without contralateral obstruction (7% vs. 6%). However, the incidence of late vascular death, exemplified by a crude rate of 14% vs. 6% (p = 0.1; O.R. = 2.50; C.I. = 0.77-8.25) was greater in patients with contralateral occlusion. CONCLUSIONS: In this study, CEA in patients with contralateral occlusion was not associated with an increased perioperative morbidity/mortality rate. The higher incidence of vascular death in the late follow-up of patients with contralateral carotid occlusion, although not statistically significant, could indicate the presence of more severe systemic vascular disease.

Aged↗
PubMed1994

Divergence of genetic sequences for the vacuolating cytotoxin among Helicobacter pylori strains.

Approximately 50% of Helicobacter pylori isolates produce a cytotoxin in vitro that induces vacuolation of eukaryotic cells. Screening a lambda ZapII library of H. pylori 60190 chromosomal fragments permitted the identification of a 3864-base pair (bp) open reading frame (vacA) that encoded the vacuolating cytotoxin, and a > or = 567-bp upstream gene that was homologous to Escherichia coli cysteinyl-tRNA synthetase. The sequence data suggest that a 33-amino-acid leader sequence and a C-terminal peptide are cleaved from a 139-kDa protoxin to yield the mature 87-kDa cytotoxin. The vacA gene product contains a C-terminal motif that is present in several other bacterial proteins that undergo C-terminal cleavage, including IgA proteases of Haemophilus influenzae and Neisseria gonorrhoeae. Isogenic H. pylori mutants with insertional mutation of the vacA gene lacked vacuolating cytotoxin activity and failed to produce the 87-kDa protein. Southern analysis of naturally occurring tox-H. pylori strains with vacA probes indicated the presence of hybridizing bands, but both Southern analysis and polymerase chain reaction studies suggested that the vacA sequences of tox- strains differed from those of tox+ strains. Sequence analysis of a 1541-bp region of polymerase chain reaction-amplified vacA from tox- strain 87-203 indicated 64.8% amino acid identity with the corresponding region from tox+ strain 60190. Thus, sequence divergence in vacA genes may explain the lack of functionally active cytotoxin production by some H. pylori isolates.

Amino Acid Sequence↗