Adjuvant electron-beam IORT in high-risk head and neck cancer patients.
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Adult↗
Biomedical subjects
A S Chan
Publications and source records attributed to A S Chan.
Illness behavior influences the outcome of laparoscopic antireflux surgery.
BACKGROUND: While gastroesophageal reflux is amenable to medical and surgical treatment, the severity of pathophysiologic changes of the disease correlates poorly with the symptomatology. Similarly, the overall successful outcome of surgical therapy can be lessened by the poor outcome in a small number of patients despite the technical success of the operation. We conducted a study to determine the influence of illness behavior on the outcome and efficacy of laparoscopic Nissen fundoplication. STUDY DESIGN: From a larger group of patients undergoing a laparoscopic Nissen fundoplication, 77 patients (57 male, 20 female) completed an illness behavior questionnaire before and after surgery. This previously validated questionnaire assessed 10 scales of illness behavior. The results were compared with visual analog scales of outcome for overall satisfaction, heartburn, and solid food dysphagia, which were elicited independently from a standardized clinical follow-up questionnaire. RESULTS: Patients completed the questionnaire on average 2 months before and 25 months after surgery. High preoperative and postoperative scores for the "affective" and "hypochondriacal" scales were associated with poorer satisfaction with the surgical outcome. Although successful relief of reflux symptoms was unrelated to any preoperative illness behavior scale, postoperative scores for "disease conviction" and "disease affirmation" were predictors of further symptomatic heartburn in a small group of patients. Dysphagia did not correlate with illness behavior. When preoperative and postoperative scores were compared, no change in illness behavior was demonstrated, with the exception of lower scores for disease conviction and disease affirmation. CONCLUSIONS: These results suggest that while patient perception of disease is improved by laparoscopic fundoplication, patient satisfaction with the surgical outcome is in part determined by preoperative illness behavior.
Female↗
Localization of nitrergic neuronal and non-neuronal cells in the ultimobranchial glands of the chicken.
The ultimobranchial glands of 20 chickens, aged 2-3 months, were investigated for their nicotinamide adenine dinucleotide hydrogen phosphate-diaphorase (NADPH-d) reactivity and the distribution of nitric oxide synthase (NOS), using NADPH-d histochemistry and NOS immunocytochemistry respectively. Formazan, the blue reaction product of NADPH-d, was localised in the neuronal cell bodies and nerve fibres. Most of the cell bodies were found in the parenchyma. Some of them occurred in the wall of the ultimobranchial cysts, and a few in the immediate vicinity of the blood vessels. Labelled nerve fibres mostly travelled with blood vessels, while few of them appeared in the cystic lining. In addition to neuronal profiles, some C cells, cystic lining, and vascular endothelium were also labelled. NOS staining was found in neuron-like cells and fibres that were confirmed as neurons in adjacent sections stained with antibodies against neuron-specific enolase. It was also detected in cystic lining and in some C cells, but not in vascular endothelium. The distribution patterns of NADPH-d and NOS suggest that NO may play a role in the regulation of the secretory activity of and the blood flow through the ultimobranchial glands.
Animals↗
Histochemical and immunohistochemical localisation of nitrergic neuronal and non-neuronal cells in the bursa of Fabricius of the chicken.
The bursa of Fabricius of 24 chickens, 2-4 weeks old, was investigated to determine the distribution of nicotinamide adenine dinucleotide hydrogen phosphate-diaphorase (NADPH-d) staining and nitric oxide synthase (NOS) antigen, by use of NADPH-d histochemistry and NOS immunohistochemistry, respectively. NADPH-d reaction product was localised in neuronal cell bodies and nerve fibres. The stained cell bodies were predominantly in the different bursal compartments; some occurred in the wall and between the lymphoid follicles, and some in the immediate vicinity of blood vessels. Stained nerve fibres travelled mostly with blood vessels, but many were also observed in the connective tissue of the bursa, independent of blood vessels, and some in contact with the lymphoid follicle and interfollicular epithelium. In addition to neuronal profiles, the interfollicular epithelium of the plicae, and the vascular endothelium were densely stained, and lymphocytes were moderately labelled. NOS immunoreactivity was found in neuron-like cells and fibres which were confirmed to be neuronal in adjacent sections stained with antibodies raised against neuron-specific enolase. It was also detected in interfollicular epithelium and lymphocytes but not in vascular endothelium. The distribution patterns of NADPH-d and NOS suggest that nitric oxide (NO) may play a role in the regulation of the secretory activity of interfollicular epithelium and the blood flow through the bursa.
Animals↗
Chromosomal 11 alterations in non-small-cell lung carcinomas in Hong Kong.
We examined 60 non-small-cell lung cancer (NSCLC) patients for evidence of genetic alterations on chromosome 11 with nine polymorphic markers by Southern blot and microsatellite marker analysis. These analyses detected genetic alterations at both the 11p and 11q arms. At the 11p15 Ha-ras locus, the loss of heterozygosity (LOH) occurred in three out of 11 (27.3%) of the informative cases; at the 11p11-q12 D11S149 locus, the LOH occurred in two out of nine (22.2%) of the informative cases; and at the 11q13 INT-2 locus, the LOH occurred in four out of 18 (22.2%) of the informative cases. Microsatellite markers in the 11q12-q13 region revealed genetic alterations for PYGM in eight out of 54 (14.8%) of the specimens studied and 10 out of 55 (18.2%) of the specimens for the INT-2 marker. The data suggest genetic alterations occur in some of the lung cancer patients in both the 11p and 11q regions.
Adult↗
Ultrastructural localisation of NADPH-diaphorase in the chick thymic medulla.
Nicotinamide-adenine-dinucleotide phosphate-diaphorase positive cells in the chick thymus were studied at the electron-microscopic level. The formazan, a marker for the enzyme nitric oxide synthase, labelled cystic, undifferentiated, endocrine-like and myoid cells in the medulla. Some lymphoid and reticulo-epithelial cells were also lightly labelled. The reaction product was predominantly bound to the membranes of the endoplasmic reticulum in all the cells labelled and also to the nuclear envelope and outer membrane of mitochondria. The Golgi apparatus and the plasma membrane were free of the reaction product.
Amino Acid Oxidoreductases↗
Alternating nitroglycerin and syntocinon to facilitate uterine exploration and removal of an adherent placenta.
Nitroglycerin (NTG) has been demonstrated to provide uterine relaxation in the management of various obstetric complications. A 32-yr-old woman presented 40 min postpartum for manual removal of a retained placenta. Repeated, alternating doses of NTG 250 micrograms and syntocinon (SYN) 10U iv were used over 15 min to produce periods of uterine relaxation and contraction respectively for uterine exploration. Multiple attempts to extract the placenta failed and a diagnosis of placenta accreta was made. There were no major side effects from this combination of drugs apart from a transient 20% decrease in blood pressure after NTG, which responded to ephedrine 10-15 mg iv. The rapid change in uterine tone was believed to be due not only to the short duration of action of NTG and SYN, but also to the possible physiological antagonism between the two drugs. The mechanism of interaction may involve calcium mobilization and myosin light chain phosphorylation. We conclude that NTG and SYN can be used to produce alternating periods of uterine relaxation and contraction rapidly and consistently with little sustained effects from either agents.
Adult↗
Semantic network abnormality predicts rate of cognitive decline in patients with probable Alzheimer's disease.
The present study examined the relationship between rate of cognitive decline in patients with Alzheimer's disease (AD) and the integrity of the network of associations that comprise their semantic knowledge. The integrity of the semantic network of 12 AD patients was determined by comparing their networks to a standard normal control network derived with Pathfinder analysis, a multidimensional graphic analysis technique. A simple linear regression analysis, comparing the degree of semantic network deterioration with rate of cognitive decline as measured by the difference between the Dementia Rating Scale (DRS) scores obtained at the time of the testing of semantic knowledge (Year 1) and one year later (Year 2), was highly significant (r2 = .84; p < .001). These results suggest that a sensitive measure of the structural deterioration of semantic knowledge may be useful for predicting the rate of progression of cognitive changes in patients with AD.
Aged↗
Ultrastructure of myoid cells in the chick thymus.
1. The ultrastructure of the myoid cells in the thymus of 2-week old chicks was examined by electron microscopy. 2. Myoid cells are round or elongated, distributed singly or in clusters in the medulla and at the corticomedullary junction. They are interposed between reticular epithelial cells to provide support for the meshwork of the microenvironment. They are also inserted into intercellular cysts, or associated with blood vessels and endocrine-like cells. 3. The cytoplasm of the myoid cell is packed with myofibrils arranged in circular bundles around the nucleus, aligned in register to form sarcomeres or randomly distributed. The interfibrillar cytoplasm contains smooth endoplasmic reticulum, mitochondria and free ribosomes. 4. The myoid cells contribute to the formation of the structural framework of the medulla. Their association with intercellular cysts and blood vessels suggests that their contractility may affect cystic and vascular flow.
Animals↗
A role for phosphatidylinositol 3-kinase in the regulation of beta 1 integrin activity by the CD2 antigen.
The rapid and reversible upregulation of the functional activity of integrin receptors on T lymphocytes is a vital step in the adhesive interactions that occur during successful T cell recognition of foreign antigen and transendothelial migration. Although the ligation of several different cell surface receptors, including the antigen-specific CD3/T cell receptor complex, the CD2, CD7, and CD28 antigens, as well as several chemokine receptors, has been shown to rapidly upregulate integrin function, the intracellular signaling events that initiate this increase in adhesion remain poorly defined. In this study, we have used DNA-mediated gene transfer to explore the role of phosphatidylinositol 3-kinase (PI 3-K) in the upregulation of beta 1 integrin functional activity mediated by the CD2 antigen. CD2 was expressed in the myelomonocytic cell line HL60, which expresses beta 1 integrins that mediate adhesion to fibronectin and VCAM-1 in an activation-dependent manner. Antibody stimulation of CD2 expressed on HL60 transfectants resulted within minutes in increased beta 1-mediated adhesion to fibronectin and VCAM-1 at levels comparable to that obtained upon stimulation with the phorbol ester PMA. A role for PI 3-K in CD2-mediated increases in beta 1 integrin function is suggested by: (a) the ability of the PI 3-K inhibitor wortmannin to completely inhibit CD2-induced increases in beta 1 integrin activity; (b) the association of PI 3-K with CD2; and (c) induced PI 3-K activity upon CD2 stimulation. The mode of association of PI 3-K with CD2 is not mediated by tyrosine phosphorylation-dependent binding of PI 3-K via SH2 domains, since: (a) PI 3-K is associated with CD2 in unstimulated cells; (b) CD2 stimulation fails to increase the amount of associated PI 3-K; and (c) the CD2 cytoplasmic domain lacks tyrosine residues. A role for both protein kinase C and cytoskeletal rearrangements in CD2 regulation of integrin activity is also suggested, since a PKC inhibitor partially inhibits CD2-induced increases in beta 1 integrin function, and CD2 stimulation increases F-actin content in a wortmannin-sensitive manner. Analysis of human peripheral T cells indicated that CD2 stimulation also results in PI 3-K-dependent upregulation of beta 1 integrin activity. Thus, these results demonstrate that CD2 can function as an adhesion regulator in the absence of expression of the CD3/T cell receptor complex; and directly implicate PI 3-K as a critical intracellular mediator involved in the regulation of beta 1 integrin functional activity by the CD2 antigen.
Actins↗
Bronchoscopic findings of a tension pneumothorax.
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Bronchoscopy↗
Distinct distributions of mu, delta and kappa opioid receptor mRNA in rat brain.
We present a comprehensive comparison of the anatomical distributions of the cloned mu, delta and kappa opioid receptor mRNA in rat brain. Northern blot analysis revealed that mRNA species encoding the three receptors differed in size and were differentially localized in brain regions. In peripheral tissues analyzed, the 3 mRNA species were detected only in the spinal cord. The distributions of mu, delta and kappa receptor mRNA in rat brain were examined by in situ hybridization histochemistry using gene-specific probes. Mu receptor mRNA was predominately localized to thalamic, brainstem and reticular core nuclei and was highest in the habenular and thalamic nuclei. In contrast, kappa receptor mRNA was expressed in hippocampus including dentate gyrus, hypothalamic and some thalamic nuclei and also present in cortex, caudate putamen, olfactory tubercle and nucleus accumbens. Delta receptor mRNA was prominent in cerebral cortex, olfactory tubercle, hippocampus, caudate putamen and nucleus accumbens. These results show that the mRNA distribution for each opioid receptor subtype in brain is unique and correlate well with the known distribution of the corresponding opioid receptor binding sites.
Animals↗
Prognostic significance of proliferating cell nuclear antigen expression in hepatocellular carcinoma.
BACKGROUND: Proliferating cell nuclear antigen (PCNA) is a nuclear protein synthesized in G1/S-phase of the cell cycle and therefore is related to cell proliferative activity. In an attempt to evaluate its prognostic significance and clinicopathologic correlation in patients with hepatocellular carcinoma (HCC), the proliferative activity was studied using immunohistochemical staining with monoclonal antibody to PCNA. METHODS: Seventy-two patients (64 men, 8 women; mean age, 52 years [range, 24-77 years]) having HCC surgically resected were studied. Tumor and nontumor tissues were selected from each case and stained with PCNA antibody. Tumor and nontumor PCNA (T-PCNA and NT-PCNA) scores were assessed by counting the positive staining nuclei per 1000 cells. RESULTS: The T-PCNA score ranged from 10 to 894 per 1000 cells (mean +/- standard deviation = 333 +/- 263). It was found to be significantly and positively associated with positive margin (P = 0.003), direct liver invasion by tumor (P = 0.021), and venous permeation (P = 0.020), features directly or indirectly related to tumor invasiveness. However, it had no significant association with tumor size, cellular differentiation, or patients' hepatitis B surface antigen (HBsAg) status. When the tumors were stratified into two groups with a T-PCNA score less than or equal to 200 and a T-PCNA score greater than 200, those patients with a T-PCNA score less than or equal to 200 had significantly longer disease-free survival (DFS) and actual survival (AS) rates than those with scores greater than 200 (median DFS and AS, 34.6 and 49.3 months and 7.7 and 19.1 months, respectively; P = 0.019 and 0.035 for DFS and AS, respectively). T-PCNA and NT-PCNA scores had no significant correlation with the HBsAg status of the patients. CONCLUSIONS: Proliferative activity in HCC, as defined by PCNA immunohistochemical analysis, is significantly related to tumor invasiveness. It is also a potentially valuable prognostic factor in patients with this tumor.
Adult↗
Tyrosine kinase activity associated with the CD7 antigen: correlation with regulation of T cell integrin function.
Rapid up-regulation of the functional activity of integrin adhesion receptors is a hallmark of T cell activation. Monoclonal antibody engagement of the CD7 antigen on human T cells results in an increase in beta 1 and beta 2 integrin-mediated adhesion within minutes. This suggests that CD7 is capable of transducing intracellular signals, and is consistent with other indirect studies implicating CD7 as a signaling receptor on T cells. In this report, we have explored the intracellular mechanism by which CD7 modulates integrin functional activity. First, CD7-mediated up-regulation of T cell adhesion was found to be unique when compared to phorbol ester stimulation and CD3/T cell receptor cross-linking, based on differences in the kinetics of activation-dependent integrin-mediated adhesion and lack of increase in CD2 functional activity. Second, up-regulation of integrin activity mediated by CD7 cross-linking was completely inhibited by the tyrosine kinase inhibitor herbimycin A. Third, antiphosphotyrosine immunoblotting demonstrated that antibody engagement of CD7 results in a rapid but transient increase in tyrosine phosphorylation in human T cells. Finally, CD7 immunoprecipitates contain in vitro kinase activity, as demonstrated by phosphorylation of a predominant band of 80 kDa and multiple other bands. Phosphoamino acid analysis of the 80-kDa substrate revealed phosphorylation on tyrosine as well as serine and threonine residues. Together, our results suggest that CD7 is associated with tyrosine kinase activity and that this tyrosine kinase activity correlates with the ability of CD7 to regulate T cell integrin functional activity.
Antigens, CD↗
Localization of NADPH-diaphorase reactivity in the chick and mouse thyroid gland.
In the present study, nicotinamide adenine dinucleotide hydrogen phosphate-diaphorase (NADPH-d) histochemistry has been used as a marker for nitric oxide synthase (NOS). The colored reaction product, formazan, was localized in neuronal cell bodies, nerve fibers, and vascular endothelium in the thyroid of chick and mouse. In these two animal species, most of the NADPH-d-labeled neuronal cell bodies were found in the thyroid capsule and interfollicular connective tissue while some were associated with blood vessels. Most nerve fibers travelled with blood vessels supplying the thyroid gland, while a few of them were intimately associated with the thyroid follicular cells. Control sections not incubated with beta-NADPH failed to show labeling of the above structures. It is concluded that nitric oxide may play an important role in endocrine secretion by controlling the regional blood flow in the thyroid gland and by directly acting on the thyroid follicular cells.
Amino Acid Oxidoreductases↗
Susceptibility of three laboratory strains of Anopheles albimanus (Diptera: Culicidae) to coindigenous Plasmodium vivax in southern Mexico.
Three morphologically different pupal phenotypes (green, striped, brown) were selected from a parent strain of Anopheles albimanus Wiedemann collected from the Suchiate region in the state of Chiapas, Mexico. Significant differences in susceptibility to coindigenous Plasmodium vivax Grassi & Feletti were observed when striped was compared with the parent colony as well as with brown and with green phenotypes. Differences in susceptibility were not significant between the other phenotypes and the parent colony.
Animals↗
Ultrastructure of epithelial cells of the chick embryo thymus.
The ultrastructure of the stromal cells of the thymuses of chick embryos from the 13th to 19th day of incubation was investigated. At the 13th day, the non-lymphoid elements consist mainly of undifferentiated and epithelial cells. The dominant cystic cells are organized to form intra- and intercellular cysts and cleft-like spaces. By the 15th day, cysts are more conspicuous, and the cystic cells are marked by an increase in cytoplasmic organelle content. Isolated foci of cystic cells with no apparent connections to cysts are also observed. Myoid cells, characterized by the presence of myofibrils, are identifiable at this stage. Endocrine-like cells show synthetic and secretory activities and are distributed in cystic epithelium or among other cell types. Dendritic cells and macrophages are also observed among the other cells. Between the 15th and 19th day, there is a further increase in size and frequency of the cysts. Myoid and endocrine-like cells are also more prevalent.
Animals↗
Lack of effect of supplemental dietary selenium on time to development of radiation-induced cutaneous tumors in rats.
Sprague-Dawley 8-week-old male rats received a single dose of 1425 cGy to the skin of the back using a 6 meV electron beam. Three days later they were randomized into three groups receiving supplemental dietary selenium as sodium selenite at levels of 0 ppm, 1 ppm, and 2 ppm selenium. Cutaneous tumors first appeared 33 weeks after irradiation and the experiment was terminated at 63 weeks. A wide variety of epithelial and connective tissue tumors developed. There was no significant difference in the time to development of epithelial or connective tissue tumors between the three groups. Thus, under the conditions of this experiment an inhibitory effect of dietary selenium on radiation-induced skin tumors was not evident.
Animals↗