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Biomedical subjects

P Dong

Publications and source records attributed to P Dong.

At least 19 recordsLinked to original sources
PubMed2004

Enhanced quality and quantity of retrieval of Critically Appraised Topics using the CAT Crawler.

As healthcare moves towards the implementation of Evidence-Based Medicine (EBM), Critically Appraised Topics (CATs) become useful in helping physicians to make clinical decisions. A number of academic and healthcare organizations have set up web-based CAT libraries. The primary objective of the presented work is to provide a one-stop search and download site that allows access to multiple CAT libraries. A web-based application, namely the CAT Crawler, was developed to serve physicians with an adequate access to available appraised topics on the Internet. Important information is extracted automatically and regularly from CAT websites, and consolidated by checking the uniqueness and availability. The principle of meta-search is incorporated into the implementation of the search engine, which finds relevant topics following keyword input. The retrieved result directs the physician to the original resource page. A full-text article of a particular topic can be converted into a proper format for downloading to Personal Digital Assistant (PDA) devices. In summary, the application provides physicians with a common interface to retrieve relevant CATs on particular clinical topics from multiple resources, and thus speeds up the decision making process.

Algorithms↗
PubMed2004

Same day outpatient transjugular liver biopsies in haemophilia.

Patients with haemophilia are at increased risk of hepatitis C infection because of prior transfusion of blood products. Virtually all haemophiliacs who received pooled blood products before the mid-1980s have been infected with hepatitis C. A liver biopsy is important to identify the extent of liver disease, and to help determine the necessity of interferon therapy. With factor replacement, in-hospital liver biopsy is safe. Thirty patients with haemophilia were evaluated for chronic hepatitis C infection. Eleven patients subsequently underwent successful transjugular liver biopsy in the outpatient setting after appropriate factor replacement. Mean +/- SD pre- and posthaemoglobin values were 15.8 +/- 0.79 and 14.4 +/- 0.71 g dL(-1) (P = ns). There was no significant change in heart rate, systolic or diastolic blood pressure during the monitoring period (P = ns) and no major complication was noted in perioperative follow-up. The mean length of the liver biopsy specimens was 1.7 +/- 0.3 cm, mean grade was 2 +/- 0.6 and mean stage was 2.3 +/- 1.2. Our experience demonstrates that outpatient transjugular liver biopsy can be safely performed in patients with haemophilia in the outpatient setting, avoiding the cost and need for hospital admission.

Adult↗
PubMed2002

Serum levels of CC16, SP-A and SP-B reflect tobacco-smoke exposure in asymptomatic subjects.

Since the 16-kDa bronchiolar Clara cell protein (CC16) and the alveolar surfactant-associated proteins (SP)-A and -B leak into the circulation when parenchymal health is disturbed, the aim of this study was to determine whether their serum levels could serve as early peripheral markers of tobacco smoke-induced epithelial injury. Sixty-nine (51 yrs (32-54) median (25-75th percentile)) nonsmokers and 54 (42 yrs (31-53)) asymptomatic smokers were enrolled in the study. Serum levels of SP-A did not differ between subjects (270 (208-389) versus 259 (168-392) microg x L(-1)), however, CC16 levels decreased (10.6 (8.7-14.6) versus 7.6 (6.0-11.2) microg x L(-1)) and SP-B levels increased (2,529 (2,091-2,943) versus 3,053 (2,613-4,188) microg x L(-1)) in the smokers. When tobacco smoke exposure, serum creatinine (renal index), age and sex were used as independent variables, CC16 was negatively influenced by cumulative smoking and positively influenced by age. SP-A and -B were negatively influenced by creatinine and positively influenced by cumulative smoking. Serum SP-B was inversely correlated with forced expiratory volume in one second/vital capacity, suggesting an association between obstructive disease and parenchymal lung health. The authors suggest that serum surfactant-associated proteins-A and -B reflect increased alveolocapillary leakage whereas Clara cell secretory protein 16 reflects tobacco smoke-induced Clara cell toxicity. Their evaluation may allow the effects of tobacco smoke on different levels of the respiratory tract, cellular toxicity and epithelial leakage to be distinguished.

Adolescent↗
PubMed2001

Bleeding complications associated with the use of rt-PA versus r-PA for peripheral arterial and venous thromboembolic occlusions.

This article analyzes the early experience with alteplase (rt-PA) and reteplase (r-PA) to identify noteworthy differences in bleeding and to determine correlations with dosage, concomitant anticoagulation, and duration of infusion. A retrospective review of the medical records was unavailable for the initial 82 patients who were treated with either rt-PA (44) or r-PA (38) for peripheral arterial or venous occlusions after urokinase therapy. Successful recanalization was achieved in 31/44 (70%) of the patients treated with rt-PA and in 34/38 (89%) of the patients treated with r-PA. Significant bleeding was documented in 20/44 (45%) of the rt-PA-treated patients (including 14 transfusions) versus 3/38 (8%) of the r-PA-treated patients (3 transfusions). Concomitant anticoagulation with either preceding warfarin (international normalized ratio > 1.1) or a bolus of heparin at the outset of the infusion was associated with significant bleeding in 13/17 (76%) of the rt-PA-treated patients (including 9 transfusions) versus 0/17 in the r-PA-treated patients. No significant correlation between either mean dose or total dose and bleeding was shown for either drug. Early experience indicates that r-PA is at least as effective as rt-PA for the thrombolysis of peripheral arterial and venous occlusions. It also appears that r-PA is less likely than rt-PA to be associated with significant bleeding during such infusions, especially if the patient is concomitantly anticoagulated.

Adolescent↗
PubMed2001

Progesterone modulation of D5 receptor expression in hypothalamic ANP neurons, the role of estrogen.

Aberrant responses to dopamine consequent to a reduction of D1-like receptors in critical regions of the brain have been implicated in schizophrenia. Whereas estrogen may protect against the onset and incidence of psychosis in the illness, the neurobiological effects of the ovarian steroid remain unclear. Recently we have shown that estrogen augments the expression of D5 receptors, a member of the D1-like receptor family, in central neurons and enhances the functions of the host cells. Employing rat hypothalamic neuron cultures, we report here that another important ovarian steroid, progesterone, also augments dopamine D5 receptor expression in hypothalamic atrial natriuretic factor (ANP) neurons. However, unlike the effect of estrogen, progesterone acts indirectly through potentiating estrogen-mediated changes that include enhancement of D5 receptor expression, immunoreactive (ir)-ANP release and pro-ANP mRNA abundance. We conclude that whilst progesterone has little effect by itself, the steroid works in synergism with estrogen to augment the function of ANP neurons. The possibility that progesterone may further enhance the protective effect of estrogen against the incidence of psychosis in schizophrenia now needs to be considered.

Animals↗
PubMed2001

The predictive value of p53, Ki-67 and angiogenetic factors in primary hypopharyngeal carcinoma.

To evaluate the predictive role of the oncogene p53, the proliferating marker Ki-67, angiogenic factors platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/dThdPase) and vascular endothelial growth factor (VEGF) in primary hypopharyngeal carcinoma, we immunohistochemically studied a series of 84 primary hypopharyngeal carcinoma patients who were treated at the Department of Otolaryngology of Kurume University Hospital between 1990 and 1997. The correlation of each score according to the intensity and percentage of the labeled cells with the TNM stage, histological grade, metastasis and survival status was analyzed. The positive rate of p53 was 52.4%. The percentages of Ki-67 labeled cells in patients with or without metastasis showed a significant difference (p = 0.011). VEGF also showed a significant difference between the live and death groups (p < 0.05) and also among the differentiation group (p < 0.05). A statistically significant correlation was also seen between the score of Ki-67 and VEGF (r = 0.438, p < 0.001) or the score of Ki-67 and PD-ECGF (r = 0.259, p < 0.001), respectively. In conclusion, the present study suggests that a correlation exists between proliferating and angiogenesis, and VEGF and Ki-67 are thus considered to be possible prognostic discriminators in hypopharyngeal carcinoma.

Adult↗
PubMed2000

Fundus microvascular flow monitoring during retrograde cerebral perfusion: an experimental study.

BACKGROUND: Retrograde cerebral perfusion (RCP) through the superior vena cava was clinically introduced as a supportive technique to protect the brain during deep hypothermic circulatory arrest. This study searched for a direct monitor of cerebral blood flow to evaluate the effect of cerebral perfusion. METHODS: Retinal microvascular perfusions were studied in six piglets using fundus fluorescein angiography (FFA) and color Doppler sonography before cardiopulmonary bypass and retrograde cerebral perfusion during deep hypothermic circulatory arrest. RESULTS: FFA showed initial filling of the fundus venae in 2.5 minutes, and complete filling in 4.5 minutes with partial filling of the arteriae. Arteriae completely filled in 8 minutes, and all of the arteriae and venae filled from 15 to 17 minutes. Color Doppler sonography showed that flow signals were detected in all of the fundus vessels during RCP. CONCLUSIONS: FFA and color Doppler sonography are direct and sensitive methods for observing cerebral blood flow and assessing the effect of cerebral perfusion.

Animals↗
PubMed2000

Endovascular treatment of dural sinus thrombosis with rheolytic thrombectomy and intra-arterial thrombolysis.

BACKGROUND AND PURPOSE: Cerebral venous thrombosis is a rare entity that can be difficult to manage. Intrasinus thrombolysis is an increasingly applied intervention, but this modality carries an increased risk of hemorrhage. We describe for the first time an option with a potentially lower incidence of intracranial bleeding, the combination of the AngioJet rheolytic thrombectomy catheter with intra-arterial thrombolysis, in 2 patients with extensive dural sinus thromboses, preexisting intracranial hemorrhage, and severe progressive neurological deficits despite heparin therapy. METHODS: Four procedures were performed in 2 patients with thromboses in the superior sagittal and transverse sinuses (right in 1 patient and bilateral in 1 patient) and cortical veins. Rheolytic thrombectomy was performed in the sigmoid, transverse, straight, and superior sagittal sinuses; this technique involves the use of the Bernoulli effect to create a vacuum that fragments and aspirates thrombus. For associated persistent cortical vein thromboses, low-dose intra-arterial thrombolysis was used. RESULTS: Both patients had excellent angiographic results with sinus reopening after rheolytic thrombectomy and cortical vein reopening after intra-arterial thrombolysis. Follow-up CT showed no change in 1 patient and increased preexisting intracranial hemorrhage in the other. One patient had a negative hypercoagulable workup, and the other patient had probable anti-phospholipid antibody syndrome. At 6 months, both patients had excellent clinical outcome with no neurological deficits except mild short-term memory loss in 1 patient. CONCLUSIONS: The combination of rheolytic thrombectomy with intra-arterial thrombolysis is a treatment modality that allows accelerated recanalization of occluded dural sinuses and cerebral veins with lower doses of thrombolytic agents.

Adult↗
PubMed1999

D5 dopamine receptors mediate estrogen-induced stimulation of hypothalamic atrial natriuretic factor neurons.

Whereas progesterone and dopamine share a common central pathway to modulate sexual behavior in female rats, the way in which estrogen is involved remains unclear. In a long-term rat hypothalamic cell culture system, atrial natriuretic factor-producing neurons were identified as candidate sites for integration of sex steroid action. Estrogen induces the expression of progesterone receptors in atrial natriuretic factor neurons and also augments neuronal functions by increasing expression of constitutively active D5 receptors that generate cAMP in a ligand-independent manner. Such a cross-talk mechanism allows estrogen to exert its effects via the adenylyl cyclase-cAMP system by augmenting dopamine receptor activity, an action that may play an important integrative role in facilitating female sexual behavior.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1999

[Expression and clinical implication of multidrug resistant-associated protein gene (MRP) in patients with laryngeal squamous cell carcinoma].

OBJECTIVE: To study the relationship between the expression of MRP mRNA and the clinical pathological characteristics of the patients with laryngeal squamous cell carcinoma. METHOD: Reverse transcription polymerase chain reaction (RT-PCR) assay was used to detect the expression of MRP mRAN in 35 patients. RESULT: The positive expression rate of MRP mRAN was 45.7 percent (16/35) in laryngeal carcinoma. It was higher in advanced (T3-4) patients than that in early (T1-2) cases (P < 0.05) and showed a significant correlation with metastases of cervical lymph node (P < 0.01). CONCLUSION: It is suggested that the expression of MRP mRNA may not only play an important role in multidrug resistance of laryngeal carcinoma, but also influence their biological behavior of dissemination and metastases.

Adult↗
PubMed1998

p53-independent role of MDM2 in TGF-beta1 resistance.

Transforming growth factor-beta (TGF-beta) inhibits cell proliferation, and acquisition of TGF-beta resistance has been linked to tumorigenesis. A genetic screen was performed to identify complementary DNAs that abrogated TGF-beta sensitivity in mink lung epithelial cells. Ectopic expression of murine double minute 2 rescued TGF-beta-induced growth arrest in a p53-independent manner by interference with retinoblastoma susceptibility gene product (Rb)/E2F function. In human breast tumor cells, increased MDM2 expression levels correlated with TGF-beta resistance. Thus, MDM2 may confer TGF-beta resistance in a subset of tumors and may promote tumorigenesis by interference with two independent tumor suppressors, p53 and Rb.

Animals↗
PubMed1998

Cloning, characterization, and the complete 56.8-kilobase DNA sequence of the human NOTCH4 gene.

The first complete mammalian genomic sequence reported thus far in the Notch gene family, including a putative promoter region and 30 exons of the human NOTCH4 gene spanning 56.8 kb of DNA, were sequenced. The NOTCH4 locus contains a TATA-less promoter with two putative transcription initiation sites (Inr), three RBP-Jkappa sites, and two GATA recognition sites. Two cDNA isoforms, NOTCH4(L) and NOTCH4(S),were identified. Whereas the NOTCH4(S) isoform contains the entire coding sequence, the NOTCH4(L) isoform has two unspliced intronic sequences between exons 11 and 12 and exons 20 and 21 and a misspliced exon 6. Consistent with these results, two alternatively spliced isoforms of transcripts of approximately 9.3 and 6.7 kb were detected by Northern blot analysis. The predicted amino acid sequence of the NOTCH4 protein based on the NOTCH4(S) cDNA sequence contains 2003 amino acids and includes the predominant motifs of the Notch family: 29 epidermal growth factor (EGF)-like repeats, 3 Notch/lin-12 repeats, a transmembrane region, 6 cdc10/Ankyrin repeats, and a PEST domain.

Adult↗
PubMed1998

[Morphologic changes of red blood cells in various conditions under scanning electron microscope].

To study the changes of RBC in various conditions, blood clots elapsed 6 days in water and air and bloodstains stored in variant time were observed under Scanning Electron Microscope (SEM). The results showed that the morphology of RBC elapsed 6 days in water and air seemed to retain their integrity. They were measured 5, 48-5, 88 microns in diameter, whereas the RBC in the bloodstains stored 14 years were obviously disfigured and some appeared membrane cracking. However, the structure of RBC membrane was well recognized under the SEM. The morphological changes under the SEM and the forensic significance of the RBC were discussed.

Blood Stains↗
PubMed1998

[Supraglottic laryngectomy with or without one arytenoid in epiglottic carcinoma. A report of 40 cases].

OBJECTIVE: Supraglottic laryngectomy with or without one arytenoid is a functional laryngectomy suitable for treatment of epiglottic squamous carcinoma. This procedure consists of resection of the thyroid cartilage, epiglottis and the entire preepiglottic space. METHODS: Between 1990 and 1996, supraglottic laryngectomy was used to treat 40 patients with epiglottic carcinoma. The data were collected by a review of patient records and follow-up. The cancers were in stages T1(17), T2(17) and T4(6) according to the 1987 UICC cancer staging criteria. RESULTS: Twelve ipsilateral and one bilateral functional neck dissection were performed simultaneously of which 7 patients had metastasis in lymph nodes. No patient died postoperatively. Only 8(20%) had slight aspiration before the 20th day. All patients had decannulated. Twenty-nine cases received radiotherapy and chemotherapy. A follow-up analysis showed survival rate of 74% at 3 years. CONCLUSION: We propose supraglottic laryngectomy for the surgical treatment of early supraglottic carcinomas, which could acquire almost normal laryngeal function.

Adult↗
PubMed1998

[Neurilemmoma of the larynx with three case reports].

Neurilemmoma of the larynx is rare. We report three cases who were treated in our hospital in recent decade. The tumours mainly involves the aryepiglottic folds, the ventricular folds or extending to the pyriform fossa, uncommon being subglottic. It is believed that the most likely nerve of origin is the superior laryngeal nerve. Surgical approach was median laryngotomy for 2 cases and lateral pharyngotomy for 1 case.

Adolescent↗
PubMed1998

[Parapharyngeal space neoplasms].

OBJECTIVE: To study parapharyngeal space (PPS) neoplasms which are rarely seen clinically. METHODS: A retrospective review was made of 59 patients with PPS neoplasm operated on from 1986 to July, 1997 in our institution. RESULTS: Neurogenic tumors were the most common neoplasms, which constituted about 60 percent in the primary parapharyngeal space neoplasms. High-resolution computed tomography or magnetic resonance imaging was essential for diagnosis and presurgical planning. The transcervical approach was the preferred procedure for 75% benign parapharyngeal tumors. Middle mandibulotomy was used in 3 cases, including 2 small tumors confined to the superior aspect of the PPS and 1 carotid body tumor which extended to the skull base. Lateral skull base approach was utilized for 1 schwannoma originating in the jugular foramen with extension into the PPS. CONCLUSIONS: We believe that transoral approach can be used for small tumors and transparotid approach may be especially indicated for removal of deep lobe parotid tumors with extension to the PPS. Middle mandibulotomy is a safe and efficacious approach for the removal of special PPS neoplasms.

Adenoma, Pleomorphic↗
PubMed1997

Intestinal absorption of Mn-mesoporphyrin in a small bowel sac system: effect of oleic acid.

RATIONALE AND OBJECTIVES: The authors investigated the effect of oleic acid (cis-9-octadecenoic acid) (OA), a lipidic carrier, on the intestinal absorption rate and T1 relaxation time of manganese (III) mesoporphyrin (Mn-mesoporphyrin), a prototype hepatobiliary contrast agent for magnetic resonance imaging. METHODS: Mn-mesoporphyrin was formulated with OA at various concentrations. Small bowel sacs were created in 36 rats and filled with complexed and free Mn-mesoporphyrin. Intestinal absorption of Mn-mesoporphyrin was measured with spectrophotometry at 364 nm. T1 relaxation times were measured in samples of Mn-mesoporphyrin solutions, bowel wall, liver, and bile. RESULTS: Absorption rates ranged from 4.2%/cm2/h to 13%/cm2/h. Absorption was greatest (13%/cm2/h) when a combination of 1 mmol/L Mn-mesoporphyrin and 26.5 mmol/L OA was used. The T1 of bile decreased from 2,480 to 248 msec (maximum decrease) in rats that received Mn-mesoporphyrin. CONCLUSION: Mn-mesoporphyrin is absorbed from the small bowel in both the lipid-associated and free form, resulting in substantial shortening of the T1 in bile.

Animals↗