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Biomedical subjects

A Au

Publications and source records attributed to A Au.

16 recordsLinked to original sources
PubMed2001

Effects of 32P radioactive stents on in-stent restenosis in a double stent injury model of the porcine coronary arteries.

BACKGROUND: The major limitation of coronary stenting remains in-stent restenosis, due to the development of neointimal proliferation. Radioactive stents have demonstrated the ability to reduce this proliferation in the healthy nonatherosclerotic porcine animal model. However, inhibition of tissue proliferation in the in-stent restenotic lesion in a porcine model is not well characterized. The objective of this study was to examine the efficacy and safety of the 32P radioactive stent for the treatment of in-stent restenosis in a double stent injury model of the porcine coronaries. METHODS AND MATERIALS: Eighteen coronary arteries in 9 pigs underwent nonradioactive stent (8 mm in length) implantation. Thirty days after the initial stent implantation, a 32P radioactive stent (18 mm in length) with an activity of 0 and 18 microCi was implanted to cover the initial stent. The swine were killed 30 days after the second stent implantation. Histomorphometric analysis was performed for vessel area (VA), stent strut area (SSA), intimal area (IA), and lumen area (LA). RESULTS: Injury scores, VA, SSA, and LA were similar among the control and radiated groups. Neointimal formation was significantly reduced after placement of radioactive stents as compared to control in both the overlapped (0.93 +/- 0.12 vs. 1.31 +/- 0.51 mm(2), p < 0.05) and nonoverlapped segments (1.14 +/- 0.21 vs. 1.91 +/- 1.04 mm(2), p < 0.05). The smooth muscle cell index in the neointima was reduced. Intimal fibrin was increased in the radiated group as compared to the control (p < 0.01 respectively). CONCLUSIONS: 32P radioactive stents may be safe and effective in reducing neointimal formation leading to in-stent restenosis. Longer follow-up will be required to examine whether these positive findings can be maintained.

Animals↗
PubMed2001

"Edge Effect" of (32)p radioactive stents is caused by the combination of chronic stent injury and radioactive dose falloff.

BACKGROUND: Radioactive stents have been reported to reduce in-stent neointimal thickening. An unexpected increase in neointimal response was observed, however, at the stent-to-artery transitions, the so-called "edge effect." To investigate the factors involved in this edge effect, we studied stents with 1 radioactive half and 1 regular nonradioactive half, thereby creating a midstent radioactive dose-falloff zone next to a nonradioactive stent-artery transition at one side and a radioactive stent-artery transition at the other side. METHODS AND RESULTS: Half-radioactive stents (n=20) and nonradioactive control stents (n=10) were implanted in the coronary arteries of Yucatan micropigs. Animals received aspirin and clopidogrel as antithrombotics. After 4 weeks, a significant midstent stenosis was observed by angiography in the half-radioactive stents. Two animals died suddenly because of coronary occlusion at this mid zone at 8 and 10 weeks. At 12-week follow-up angiography, intravascular ultrasound and histomorphometry showed a significant neointimal thickening at the midstent dose-falloff zone of the half-radioactive stents, but not at the stent-to-artery transitions at both extremities. Such a midstent response (mean angiographic late loss 1.0 mm) was not observed in the nonradioactive stents (mean loss 0.4 to 0.6 mm; P< 0.01). CONCLUSIONS: The edge effect of high-dose radioactive stents in porcine coronary arteries is associated with the combination of stent injury and radioactive dose falloff.

Animals↗
PubMed2001

The role of visual and auditory temporal processing in reading irregular and nonsense words.

In the present study, the role of rapid visual and auditory temporal processing in reading irregular and nonsense words was investigated with a group of normal readers. One hundred and five undergraduates participated in various visual and auditory temporal-processing tasks. Readers who primarily adopted the phonological route in reading (nonsense-word readers) showed a trend for better auditory temporal resolution but readers who primarily adopted sight word skills (irregular-word readers) did not exhibit better visual temporal resolution. Both the correlation and stepwise multiple-regression analyses, however, revealed a relationship between visual temporal processing and irregular-word reading as well as a relationship between auditory temporal processing and nonsense-word reading. The results support the involvement of visual and auditory processing in reading irregular and nonsense words respectively, and were discussed with respect to recent findings that only dyslexics with phonological impairment will display temporal deficits. Further, the temporal measures were not effective discriminants for the reading groups, suggesting a lack of association between reading ability and the choice of reading strategy.

Adolescent↗
PubMed2001

Dietary energy restriction inhibits ERK but not JNK or p38 activity in the epidermis of SENCAR mice.

Ongoing studies in our laboratory have demonstrated that dietary energy restriction (DER) inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced AP-1 transcription factor binding to DNA in the epidermis of SENCAR mice. To dissect the specific signal transduction pathways through which DER inhibits the AP-1:DNA binding, we analyzed the activities of three major MAP kinases that lead to the induction of AP-1. The changes in ERK1 and ERK2 protein expression and phosphorylation were further characterized by western blot analysis. Female SENCAR mice were pre-fed ad libitum (AL) or 40% DER diet for 8-10 weeks. The kinase activities in mouse epidermis were determined by immune complex kinase assays at 0.5, 1, 4, or 6 h following treatment with 3.2 nmol TPA to the shaved dorsal backs. ERK activity at 1 h post-TPA treatment was nearly 5-fold (P< 0.005) above basal levels in AL mice while the increase was abolished in DER mice. The TPA-induced ERK activity in AL mice was accompanied by increased phosphorylation of ERK1 and ERK2 (P< 0.05), which was abrogated in DER mice. In addition, DER mice exhibited reduced expression of total ERK1 and ERK2 and higher proportions of ERK1 and ERK2 phosphorylation in comparison with AL mice (P<0.05). JNK activity was decreased at 1 and 6 h but increased at 4 h (P<0.05) post-TPA treatment. TPA did not change p38 kinase activity at the time points tested. Neither JNK nor p38 activity was altered by DER. Taken together, our results indicated for the first time that DER blocked the TPA stimulation of ERK activity and suggested that the inhibition of TPA-induced AP-1 activity by DER is likely through inhibition of ERK but not JNK or p38 kinase pathway.

Animals↗
PubMed2001

Inhibition of phorbol ester-induced AP-1-DNA binding, c-Jun protein and c-jun mRNA by dietary energy restriction is reversed by adrenalectomy in SENCAR mouse epidermis.

The aim of this study was to determine the effects of 40% dietary energy restriction (DER) relative to ad libitum feeding on AP-1-DNA binding and expression of c-Jun protein and c-jun mRNA in SENCAR mouse skin treated with acetone or 12-O-tetradecanoylphorbol 13-acetate (TPA). The role of the glucocorticoid hormone corticosterone (CCS) was investigated by adding CCS or vehicle control to the drinking water of adrenalectomized mice. AP-1-DNA binding, measured by electrophoretic mobility shift assay, showed that TPA treatment for 4 h increased AP-1-DNA binding by 2-fold over acetone controls (P < 0.05) and that DER reduced basal and TPA-induced AP-1-DNA binding in comparison with ad libitum fed groups in sham-operated mice (P < 0.05). TPA treatment increased c-Jun protein levels in control fed mice (4-fold) and in DER mice (2-fold) over basal levels 4 h post-treatment (P < 0.05). Analyzed over all groups, DER reduced c-Jun protein levels (P < 0.01) and this effect was reversed by adrenalectomy. TPA induction of c-jun mRNA was also reduced by DER compared with ad libitum fed mice (P < 0.05). Adrenalectomy and CCS supplementation demonstrated that the effects of DER on AP-1-DNA binding were mediated in part by CCS. Measurement of blood plasma CCS concentrations showed that: (i) DER increased CCS 5-fold over ad libitum fed mice in sham-operated animals (P < 0.05); (ii) adrenalectomy decreased CCS over sham-operated mice (P < 0.05); (iii) TPA treatment had no effect on CCS. Blood plasma IGF-I concentrations were unaffected by CCS modulation or TPA treatment but were decreased by DER compared with ad libitum fed mice (P < 0.05). Thus, dietary energy restriction may inhibit cancer mechanistically by reducing overall AP-1 transcription through a process that is mediated in part by glucocorticoid hormones.

Adrenalectomy↗
PubMed2001

Temporal processing ability in above average and average readers.

In the present study, we compared the rapid visual and auditory temporal processing ability of above average and average readers. One hundred five undergraduates participated in various visual and auditory temporal tasks. The above average readers exhibited lower auditory and visual temporal resolution thresholds than did the average readers, but only the differences in the auditory tasks were statistically significant, especially when nonverbal IQ was controlled for. Furthermore, both the correlation and stepwise multiple regression analyses revealed a relationship between the auditory measures and the wide range achievement test (WRAT) reading measure and a relationship between the auditory measures and a low spatial frequency visual measure and the WRAT spelling measure. Discriminant analysis showed that together both the visual and auditory measures correctly classified 75% of the subjects into above average and average reading groups, respectively. The results suggest that differences in temporal processing ability in relation to differences in reading proficiency are not confined to the comparison between poor and normal readers.

Auditory Perception↗
PubMed1999

Acute bereavement care in the emergency department: does the professional-supported volunteers model work?

The aims of our study were to study the early impact of bereavement and to evaluate the effectiveness of the bereavement care given by our multidisciplinary team to close relatives of a sudden death, measured by the intensity of grief reaction (Texas Revised Inventory of Grief). The study sample consisted of close relatives of patients certified dead at the accident and emergency department (AED) between March 1996 and February 1997. The relatives received immediate care at the AED and were supported continually by the members of the bereavement care team. The control sample (without acute bereavement care) consisted of close relatives contacted by the liaison nursing officer in the previous year. The intensity of grief reactions were assessed by the volunteer grief counsellors at 6 months. The mean score of the intensity of grief reactions were 41.8 and 34.6 in the control (n = 11) and study (n = 18) groups respectively among high risk sample (p = 0.04). However, in the low risk sample, the mean scores were 35.3 and 30.2 in the control (n = 18) and study (n = 25) groups respectively (p = 0.11). Our study suggests that the bereavement care was especially effective in reducing the intensity of the grief at 6 months in the high risk group.

Adolescent↗
PubMed1999

Same admission colon resection with primary anastomosis for acute diverticulitis.

Current standard of care for complicated diverticulitis includes urgent resection with colostomy versus antibiotic treatment, followed by delayed resection with primary anastomosis at a second admission. In certain circumstances, it is possible to perform resection and anastomosis on the same admission for acute diverticulitis. A retrospective review was completed for patients undergoing surgery for diverticulitis from 1991 to 1998. Groups included: 1) sigmoid resection with primary anastomosis on same admission (n = 18); 2) resection with protective end colostomy (n = 16); and 3) in-patient antibiotic treatment alone, followed by a second admission for resection with primary anastomosis (n = 5). Four patients initially treated with antibiotics worsened symptomatically or developed radiographic evidence of perforation and required resection with colostomy. Five patients in Group 1 had abscesses or contained perforations based on radiographic studies. Findings on CT scans did not predict treatment. Group 1 patients had uneventful recoveries and few minor complications (wound infections and an incisional hernia). One anastomotic leak occurred in Group 2 after colostomy closure. Although there will continue to be a role for emergent operation for diverticulitis, same admission sigmoid resection with primary anastomosis after antibiotic treatment is safe, uses a shorter course of antibiotics, and has a low complication rate.

Acute Disease↗
PubMed1996

Solid and papillary neoplasm of the pancreas: radiological-pathological study of five cases and review of the literature.

OBJECTIVE: To present five cases of the rare solid and papillary neoplasm of the pancreas with pathological correlation and review of the literature. PATIENTS AND METHODS: Five patients (all female, two Caucasian, one Philipino and two Hispanic) with solid and papillary neoplasm of the pancreas were reviewed. Four patients were under 28 years of age but one patient was 44 years old at presentation. Review consisted of imaging (CT in all and ultrasound in three patients), gross pathological and histological appearance (5/5 specimens), immunohistochemistry (4/5 specimens) and clinical follow-up. RESULTS: All five tumours were successfully resected without recurrence. All tumours were well-encapsulated but showed a wide spectrum of solid peripheral tumour with central cystic degeneration on imaging. Cystic spaces corresponded to haemorrhagic necrosis on histology. One tumour showed rim calcification. Immunohistological staining showed variable expression of both exocrine and endocrine markers. CONCLUSION: Although non-specific, solid and papillary neoplasm of the pancreas is characteristically a benign, well-encapsulated solid tumor with varying degree of central necrosis in young female patients. No racial predilection was demonstrated in this small series.

Adolescent↗
PubMed1994

Central nervous system tuberculosis: MRI.

The MRI findings of 18 proven cases of central nervous system (CNS) tuberculosis were reviewed; 10 patients were seropositive for HIV. All had medical, laboratory, or surgical proof of CNS tuberculosis. Eleven patients had meningitis, of whom two also had arachnoiditis. Five patients had focal intra-axial tuberculomas: four brain masses and one an intramedullary spinal lesion. Two patients had focal extra-axial tuberculomas: one in the pontine cistern, and one in the spine. In all 11 patients with meningitis MRI showed diffuse, thick, meningeal enhancement. All intraparenchymal tuberculomas showed low signal intensity on T2-weighted images and ring or nodular enhancement. The extra-axial tuberculomas had areas isointense or hypointense relative to normal brain and spinal cord on T2-weighted images. Although tuberculous meningitis cannot be differentiated from other meningitides on the basis of MR findings, intraparenchymal tuberculomas show characteristic T2 shortening, not found in most other space-occupying lesions. In the appropriate clinical setting, tuberculoma should be considered.

Adult↗
PubMed1993

Anaesthesia for adenotonsillectomy: a comparison between tracheal intubation and the armoured laryngeal mask airway.

A prototype armoured laryngeal mask airway (LMA) was compared with tracheal intubation (ETT) for anaesthesia for adenotonsillectomy. Fifty-five children were randomised into the LMA group and 54 into the ETT group. During insertion of the LMA, peripheral oxyhaemoglobin desaturation (SpO2) < 94% occurred in ten patients (18.2%) and in seven patients (13%) during tracheal intubation (NS). After opening the Boyle-Davis gag, airway obstruction occurred in ten patients (18.2%) in the LMA group and in three patients (6%) in the ETT group (P = 0.07). In five patients (9%) the LMA was abandoned in favour of tracheal intubation. In all others (91%), when the need for adequate depth of anaesthesia was realized, a satisfactory airway was achieved more rapidly than with tracheal intubation (P < 0.001), and maintained throughout surgery. Manually assisted ventilation was required in all patients in the ETT group, mean duration 373 +/- 385 sec, and in 26 patients (52%) in the LMA group, mean duration 134 +/- 110 sec, P < 0.001. Mean end-tidal CO2 (PetCO2) was 45.5 +/- 6.21 mmHg in the ETT group and 46.6 +/- 6.09 in the LMA group (NS). The LMA did not limit surgical access. Heart rate, MAP and blood loss in the LMA group were 110 +/- 21, 74 +/- 9 mmHg and 1.92 +/- 1.22 ml.kg-1 respectively, compared with 143 +/- 13 (P < 0.001), 85 +/- 12 mmHg (P < 0.001) and 2.62 +/- 1.36 ml.kg-1 (P < 0.05) with tracheal intubation. Fibreoptic laryngoscopy at the end of surgery in 19 patients in the LMA group revealed no blood in the larynx.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoidectomy↗
PubMed1991

Pattern of memory deficits in a controlled psychometric study of thalamic haemorrhage.

Twelve patients with unilateral thalamic haemorrhages were assessed psychometrically. The results were compared with control subjects matched for sex, age and years of education. The pattern of deficits and preserved abilities cannot be explained in terms of semantic/episodic distinction, but could be interpreted as manifestations of disconnection between the frontal and temporal systems.

Aged↗
PubMed1981

Identification of a mitochondrial phosphoprotein in brain synaptic membrane preparations.

A 41,000-dalton phosphoprotein in crude synaptosomal membrane fractions is characterized by its unique divalent and monovalent cation regulation. It is identified by two-dimensional gel electrophoresis as the phosphoprotein whose phosphorylation is enhanced by repetitive electrical stimulation of hippocampal brain slices. After sucrose-gradient ultracentrifugation, this phosphoprotein is found in the mitochondrial subfraction. This suggests that the electrically produced changes in the level of phosphorylation of the 41,000-dalton polypeptide are probably effects on cellular energetics rather than on specialized neural membrane function.

Animals↗
PubMed1976

Computer visualization of flow patterns for prosthetic heart valves.

Flow patterns for commonly used aortic valve prostheses were formed with the aid of fluid dynamics equations, numerical analysis techniques and computer graphics. Simulations of velocities, vorticity, pressure and certain stress values were developed by a computer and displayed for man-machine interaction. The ball, disc and tilting-disc occluders were of interest. The displays comprised both contour and perspective patterns; the latter permitting semi-quantitative evaluation of particular parameters. Comparisons between the computer simulations and those flow visualizations formed by Björk and co-workers were assessed. Although the methodology was of prime concern for presentation, the capability of the tilting-disc prosthesis for presenting a more natural flow regime was shown. Thoughts of future studies were entertained.

Aortic Valve↗