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Biomedical subjects

A Ali

Publications and source records attributed to A Ali.

At least 145 records · Page 8Linked to original sources
PubMed1999

CT and PET lung image registration and fusion in radiotherapy treatment planning using the chamfer-matching method.

PURPOSE: We present a validation study of CT and PET lung image registration and fusion based on the chamfer-matching method. METHODS AND MATERIALS: The contours of the lung surfaces from CT and PET transmission images were automatically segmented by the thresholding technique. The chamfer-matching technique was then used to register the extracted lung surfaces. Arithmetic means of distance between the two data sets of the pleural surfaces were used as the cost function. Matching was then achieved by iteratively minimizing the cost function through three-dimensional (3D) translation and rotation with an optimization method. RESULTS: Both anatomic thoracic phantom images and clinical patient images were used to evaluate the performance of our registration system. Quantitative analysis from five patients indicates that the registration error in translation was 2-3 mm in the transverse plane, 3-4 mm in the longitudinal direction, and about 1.5 degree in rotation. Typical computing time for chamfer matching is about 1 min. The total time required to register a set of CT and PET lung images, including contour extraction, was generally less than 30 min. CONCLUSION: We have implemented and validated the chamfer-matching method for CT and PET lung image registration and fusion. Our preliminary results show that the chamfer-matching method for CT and PET images in the lung area is feasible. The described registration system has been used to facilitate target definition and treatment planning in radiotherapy.

Aged↗
PubMed1999

Evidence for involvement of tumor necrosis factor-alpha in apoptotic death of bone marrow cells in myelodysplastic syndromes.

We previously reported excessive apoptosis and high levels of tumor necrosis factor-alpha (TNF-alpha) in the bone marrows of patients with myelodysplastic syndromes (MDS), using histochemical techniques. The present studies provide further circumstantial evidence for the involvement of TNF-alpha in apoptotic death of the marrow cells in MDS. Using our newly developed in situ double-labeling technique that sequentially employs DNA polymerase (DNA Pol) followed by terminal deoxynucleotidyl transferase (TdT) to label cells undergoing apoptosis, we have characterized DNA fragmentation patterns during spontaneous apoptosis in MDS bone marrow and in HL60 cells treated with TNF-alpha or etoposide (VP16). Clear DNA laddering detected by gel electrophoresis in MDS samples confirmed the unique length of apoptotic DNA fragments (180-200 bp). Surprisingly, however, phenotypically heterogeneous population of MDS cells as well as the homogenous population of HL60 cells showed three distinct labeling patterns after double labeling--only DNA-Pol reaction, only TdT reaction, and a combined DNA Pol + TdT reaction, albeit in different cohorts of cells. Each labeling pattern was found at all morphological stages of apoptosis. MDS mononuclear cells, during spontaneous apoptosis in 4 hr cultures, showed highest increase in double-labeled cells (DNA Pol + TdT reaction). Interestingly, this was paralleled by TNF-alpha-induced apoptosis in HL60 cells. In contrast, VP16 treatment of HL60 cells led to increased apoptosis in cells showing only TdT reaction. The double-labeling technique was applied to normal bone marrow and peripheral blood mononuclear cells after treatment with known endonucleases that specifically cause 3' recessed (BamHI), 5' recessed (PstI), or blunt ended (DraI) double-stranded DNA breaks. It was found that the DNA-Pol reaction in MDS and HL60 cells corresponds to 3' recessed DNA fragments, the TdT reaction to 5' recessed and/or blunt ended fragments, and a combined "DNA Pol + TdT reaction" corresponds to a copresence of 3' recessed with 5' recessed and/or blunt ended fragments. Clearly, therefore, apoptotic DNA fragments, in spite of a unique length, may have differently staggered ends that could be cell (or tissue) specific and be selectively triggered by different inducers of apoptosis. The presence of TNF-alpha-inducible apoptotic DNA fragmentation pattern in MDS supports its involvement in these disorders and suggests that anti-TNF-alpha (or anticytokine) therapy may be of special benefit to MDS patients, where no definitive treatment is yet available.

Apoptosis↗
PubMed1999

The effects of the ideal of female beauty on mood and body satisfaction.

OBJECTIVE: The present study examined changes in women's mood states resulting from their viewing pictures in fashion magazines of models who represent a thin ideal. METHOD: Female university students completed the Profile of Mood States (POMS), the Body Parts Satisfaction Scale (BPSS), and the Eating Disorder Inventory (EDI). They were then exposed to 20 slides; the experimental group (N = 51) viewed images of female fashion models and a control group (N = 67) viewed slides containing no human figures. All subjects then completed the POMS and the BPSS again. RESULTS: Women were more depressed (R2 = 0.745, p < .05) and more angry (R2 = 0.73, p < .01) following exposure to slides of female fashion models. DISCUSSION: Viewing images of female fashion models had an immediate negative effect on women's mood. This study, therefore, supports the hypothesis that media images do play a role in disordered eating.

Adolescent↗
PubMed1999

Pain during elective caesarean section under epidural anaesthesia: the effect of a 10 degrees head-up tilt position.

One hundred patients scheduled for elective caesarean section under epidural anaesthesia were randomized to have epidural loading doses in either the horizontal or a 10 degrees head-up position. They were assigned to their position only after an initial dose of 4 ml of 0.5% bupivacaine had been given. Ten minutes after this dose they were given 10 ml of 0.5% bupivacaine and 50 microg of fentanyl in their allocated position. Pain during surgery was assessed by the patients using a visual analogue scale and by a blinded anaesthetist. Giving the main dose in the head-up tilt position reduced the incidence of intea-operative pain significantly. The median pain score for the head-up position was zero while the score was two for the horizontal position. The inter-quartile range was 0 to 2 for the head-up tilt position and 0 to 4 for the horizontal position (P<0.05). Position had no significant effect on the blood pressure or Bromage score. A 10 degrees head-up tilt position is useful during the establishment of epidural anaesthesia to reduce the pain experienced by the patient during caesarean section.

Clinical Trial↗
PubMed1999

Limonoids from Swietenia macrophylla and S. aubrevilleana.

An investigation of the seeds of Swietenia macrophylla and S. aubrevilleana (Meliaceae) is reported. Three new compounds, augustineolide (1) and 3beta,6-dihydroxydihydrocarapin (2) from S. macrophylla and 6-acetoxyhumilinolide C (3) from S. aubrevilleana were isolated and characterized along with fifteen known compounds. Four of the compounds were subjected to an antifeedant bioassay on the final instar larvae of Spodoptera frugiperda. The antifeedant activity was comparable to that of bicyclononanolides previously tested.

Animals↗
PubMed1999

The biomechanical effects of angulated boxer's fractures.

Many clinical studies have demonstrated that in the conservative care of boxer's fractures (casting, with or without reduction), between 20 degrees and 70 degrees of dorsal angulation is acceptable. This biomechanical study characterized how boxer's fracture angulation affects the ability of the intrinsic muscles to initiate grip. The flexor digiti minimi and third volar interosseous were modeled in this study. Muscular excursion of the intrinsics were modeled with a cable and sheath device. Metacarpophalangeal joint flexion per unit excursion curves were collected when the metacarpal neck was at a fracture angle of 0 degree, 15 degrees, 30 degrees, 45 degrees, 60 degrees, and 75 degrees . As fracture angles increased, the distance between the origin and insertion of the flexor digiti minimi decreased, creating shortening, or slack, of the modeled muscle. Slack was defined as excursion generating no joint flexion. Muscle shortening data were integrated with Jacobsen's muscle fiber length data and Elftmann's fiber length/tension relationship to estimate how the fracture angle affects the initiation of metacarpophalangeal joint flexion and the strength of grip. According to this model's data, fracture angles of up to 30 degrees are compatible with nearly normal mechanics. A 30 degrees angulation is associated with a flexor digiti minimi grip strength of 92% maximum and preserves 78% of the intact finger's range of motion. We therefore conclude that 30 degrees is the upper limit for acceptable final angulation.

Cadaver↗
PubMed1999

Sequential activation of caspase-1 and caspase-3-like proteases during apoptosis in myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a group of hematopoietic disorders characterized by the concomitant presence of peripheral cytopenias and normocellular to hypercellular BM. This paradox has been proposed to be due to the presence of excessive proliferation matched by excessive intramedullary apoptosis of hematopoietic cells. When cultured in vitro MDS BM mononuclear cells (BMMC) undergo apoptosis within 4 h. We measured caspase-1-like and caspase-3-like activity in 22 MDS and 4 normal BM immediately following cell separation or after 4 h culture. When cultured in vitro, MDS BMMC demonstrated an increased apoptotic index within 4 h as measured by in situ end-labeling of fragmented DNA that was matched by a concurrent increase in caspase-3-like specific activity, and the two were significantly correlated. During the 4 h culture, a sequential activation of caspase-1-like and caspase-3-like activities was detected. Caspase-1-like specific activity was detected early and transiently at approximately 15 min, followed by a gradual increase in caspase-3-like-specific activity peaking at 2 h. When the broad-spectrum caspase inhibitor, Z-VAD.FMK, was included in the MDS BM aspirate 4 h culture, apoptosis was attenuated. We conclude that sequential activation of caspase-1-like and caspase-3-like activities may form the central biochemical pathway of apoptosis in BMMC from some MDS patients, and prevention of this process by caspase inhibitors may be of significant therapeutic value for these patients, in whom supportive care continues to be the mainstay of therapy.

Amino Acid Chloromethyl Ketones↗
PubMed1999

Laparoscopy and mesothelioma.

Malignant mesothelioma is a well-recognized long-term sequela of chronic asbestos exposure. Asbestos use in the United States began in the 1950s and was widespread until the mid-1970s. Although currently only 2.2 cases per million population per year are diagnosed, disease incidence is increasing because of the long latency of this neoplasm. A latency of 15-50 years means that a higher incidence of this neoplasm can be anticipated in the future. The authors report a patient with peritoneal mesothelioma and no known prior exposure to asbestos. The diagnosis was confirmed by exploratory laparoscopy, which entailed biopsies of the diaphragm and of the peritoneal and abdominal walls, and by cytologic evaluation of 700 ml ascitis fluid. At present, exploratory laparoscopy offers the quickest, safest, and least invasive way to confirm the clinical diagnosis of peritoneal malignant mesothelioma.

Aged↗
PubMed1999

How well does radionuclide dipyridamole stress testing detect three-vessel coronary artery disease and ischemia in the region supplied by the most stenotic vessel?

PURPOSE: This study was done to evaluate the accuracy of radionuclide dipyridamole stress imaging to detect multivessel disease and ischemia in segments of myocardium supplied by the most stenotic vessel. METHODS: A retrospective analysis of consecutive patients with known triple-vessel disease of at least 50% stenosis in each of the three major epicardial coronary arteries who had exercise (n=44) or dipyridamole (n=86) stress testing, or both, within 6 months of coronary angiography. RESULTS: The accuracy of dipyridamole stress testing to detect three-vessel disease was 52% and ischemia was detected in the region supplied by the most stenotic vessel in 67% of patients. The sensitivity and specificity rates of radionuclide imaging to detect ischemia in the region supplied by the vessel of tightest stenosis were 69% and 74% for the left anterior descending coronary artery (LAD), 61% and 78% for the right coronary artery (RCA), and 61% and 57% for the left circumflex coronary artery (LCX). Based on these values, in 39% of patients in whom the RCA or LCX was the most stenotic vessel and in 31% of patients in whom the LAD was the most stenotic vessel, perfusion defects were not present on their nuclear scans. CONCLUSIONS: These results have important implications for interventional cardiologists who perform angioplasty on the most stenotic vessel, because the regions supplied by these vessels may not be the most ischemic. Furthermore, dipyridamole stress imaging may significantly underestimate the number of patients with substantial three-vessel coronary artery disease when qualitative imaging is done.

Aged↗
PubMed1999

Normal thymic uptake of 2-deoxy-2[F-18]fluoro-D-glucose.

Whole-body 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) positron emission tomography (PET) of a 54-year-old woman with a history of recurrent thyroid follicular cancer and an elevated thyroglobulin level showed significant FDG uptake in the thyroid bed and anterior mediastinum. A previous scan after high-dose I-131 therapy also showed iodine uptake in these regions. Because of a lack of response to iodine therapy, the patient had surgery. Recurrent thyroid cancer was found in the neck, but the mediastinal lesion was shown to consist of normal thymus tissue. In repeated examinations performed after surgery, there was no uptake of FDG or I-131 in the anterior mediastinum. Previous treatment with a high dose of radioiodine may have contributed to visualization of a normal adult thymus with FDG PET.

Adenocarcinoma, Follicular↗
PubMed1999

North American and European porcine reproductive and respiratory syndrome viruses differ in non-structural protein coding regions.

Although North American and European serotypes of porcine reproductive and respiratory syndrome virus (PRRSV) are recognized, only the genome of the European Lelystad strain (LV) has been sequenced completely. Here, the genome of the pathogenic North American PRRSV isolate 16244B has been sequenced and compared with LV. The genomic organization of 16244B was the same as LV but with only 63.4% nucleotide identity. The 189 nucleotide 5' non-coding region (NCR) of 16244B was distinct from the LV NCR, with good conservation (83%) only over a 43 base region immediately upstream of open reading frame (ORF) 1a. Major differences were found in the region encoding the non-structural part of the ORF1a polyprotein, which shared only 47% amino acid identity over 2503 residues of the six non-structural proteins (Nsps) encoded. Nsp2, thought to have a species-specific function, showed the greatest divergence, sharing only 32% amino acid identity with LV and containing 120 additional amino acids in the central region. Nsps encoded by the 5'-proximal and central regions of ORF1b had from 66 to 75% amino acid identity; however, the carboxy-terminal protein CP4 was distinct (42% identity). The ORF 1a-1b frameshift region of 16244B had 98% nucleotide identity with LV. Consistent with previous reports for North American isolates, the six structural proteins encoded were 58 to 79% identical to LV proteins. The 3' NCR (150 nucleotides) was 76% identical between isolates. These genomic differences confirm the presence of distinct North American and European PRRSV genotypes.

5' Untranslated Regions↗
PubMed1999

Biological characteristics of myelodysplastic syndrome patients who demonstrated high versus no intramedullary apoptosis.

Spontaneous intramedullary apoptosis was measured in bone marrow (BM) biopsies of 175 patients with myelodysplastic syndromes (MDS) using in situ end-labeling (ISEL) of fragmented DNA. Two groups of high (n=71) versus low (n =43) levels of apoptosis were identified while 61 patients were ISEL-negative. Semiquantitative assessment of 3 cytokines, the number of macrophages and in vivo labeling indices (LI) were also determined from consecutive sections of the biopsy. Patients with high apoptosis levels tended to have a high LI (p=0.013), more macrophages in their BM biopsies (p=0.006) and higher tumor necrosis factor alpha (TNF-alpha) levels (not significant) compared to patients with no apoptosis. In addition, low risk MDS patients had significantly lower rates of apoptosis (p = 0.047) and lower levels of TNF-alpha (p = 0.055) compared to high-risk MDS patients. We conclude that the genesis of cytopenias in MDS is of multifactorial origin and that cytokine-associated apoptosis clearly identifies a distinct biological subgroup of patients who may benefit selectively by use of anti-cytokine therapies.

Aged↗
PubMed1999

Multiple components of the HSP90 chaperone complex function in regulation of heat shock factor 1 In vivo.

Rapid and transient activation of heat shock genes in response to stress is mediated in eukaryotes by the heat shock transcription factor HSF1. It is well established that cells maintain a dynamic equilibrium between inactive HSF1 monomers and transcriptionally active trimers, but little is known about the mechanism linking HSF1 to reception of various stress stimuli or the factors controlling oligomerization. Recent reports have revealed that HSP90 regulates key steps in the HSF1 activation-deactivation process. Here, we tested the hypothesis that components of the HSP90 chaperone machine, known to function in the folding and maturation of steroid receptors, might also participate in HSF1 regulation. Mobility supershift assays using antibodies against chaperone components demonstrate that active HSF1 trimers exist in a heterocomplex with HSP90, p23, and FKBP52. Functional in vivo experiments in Xenopus oocytes indicate that components of the HSF1 heterocomplex, as well as other components of the HSP90 cochaperone machine, are involved in regulating oligomeric transitions. Elevation of the cellular levels of cochaperones affected the time of HSF1 deactivation during recovery: attenuation was delayed by immunophilins, and accelerated by HSP90, Hsp/c70, Hip, or Hop. In immunotargeting experiments with microinjected antibodies, disruption of HSP90, Hip, Hop, p23, FKBP51, and FKBP52 delayed attenuation. In addition, HSF1 was activated under nonstress conditions after immunotargeting of HSP90 and p23, evidence that these proteins remain associated with HSF1 monomers and function in their repression in vivo. The remarkable similarity of HSF1 complex chaperones identified here (HSP90, p23, and FKBP52) and components in mature steroid receptor complexes suggests that HSF1 oligomerization is regulated by a foldosome-type mechanism similar to steroid receptor pathways. The current evidence leads us to propose a model in which HSF1, HSP90 and p23 comprise a core heterocomplex required for rapid conformational switching through interaction with a dynamic series of HSP90 subcomplexes.

Animals↗
PubMed1999

Improving aesthetics in patients with complete dentures.

An increasing number of patients with complete dentures are requesting improvements in the aesthetics of their dentures. This paper considers methods of improving aesthetics, using the information available from the existing complete dentures, pre-extraction records and resin stains.

Aged↗
PubMed1999

Effects of aerobic exercise training on indices of ventricular repolarization in patients with chronic heart failure.

BACKGROUND: Patients with chronic heart failure (CHF) have a markedly increased incidence of malignant ventricular arrhythmias. QT dispersion (QTd), defined as the difference between maximal and minimal QT intervals, reflects the regional inhomogeneity of ventricular repolarization dispersion and may mark the presence of malignant ventricular arrhythmias. PURPOSE: To determine the effects of exercise training on QTd in patients with CHF. PATIENTS: Fifteen patients with CHF and ejection fractions < 40% (mean, 28+/-9%) who were on a stable medical regimen. DESIGN AND INTERVENTION: Standardized 12-lead surface ECGs were obtained at the beginning and end of the exercise training program, and QT and JT intervals were measured manually and corrected for heart rate by using Bazett's formula. QTd, heart rate-corrected QTd (QTc-d), JT dispersion (JTd), and heart rate-corrected JTd (JTc-d) were measured in at least eight ECG leads in each patient. RESULTS: Following the cardiac rehabilitation and exercise training programs, patients with CHF had only slight improvements in exercise capacity (results were not significant). However, these patients had marked improvements in QTd (71+/-11 to 59+/-17 ms; p < 0.02), QTc-d (82+/-28 to 63+/-17 ms; p < 0.01), JTd (76+/-19 to 57+/-18 ms; p < 0.002), and JTc-d (84+/-23 to 61+/-18 ms; p < 0.001) following the exercise training programs. CONCLUSION: These data indicate that aerobic exercise training significantly reduces the indices of ventricular repolarization dispersion in patients with CHF. Further studies are needed to evaluate how effectively this reduction in ventricular repolarization dispersion decreases the risk of malignant ventricular arrhythmias and sudden death in patients with CHF.

Aged↗
PubMed1999

The relative extent and propensity of CD34+ vs. CD34- cells to undergo apoptosis in myelodysplastic marrows.

The paradox of peripheral cytopenias despite cellular bone marrow (BM) observed in myelodysplastic syndromes (MDS) has been associated with excessive intramedullary apoptosis of hematopoietic cells. Since MDS is regarded as a stem cell disorder, the present studies were undertaken to examine the relative susceptibility and propensity of early progenitor CD34+ cells to undergo apoptosis as compared to more maturing/matured CD34- cells. Five serial studies were performed on 4 independent groups of 36 newly diagnosed MDS patients. First, in 2 separate groups of 16 and 8 patients each, measurement of the extent of apoptosis in CD34+ and CD34- fractions of the BM aspirate mononuclear cells was carried out using independent biparametric flow cytometry methods, CD34 labeling/terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) (n = 16), and CD34 labeling/reduced uptake of nucleic acid staining dye LDS751 (n = 8). The difference in the median degrees of apoptosis in CD34+ vs. CD34- cells was not statistically significant by either technique (P = 0.583 and P = 0.674 for TUNEL and LDS751, respectively). In the next group of 4 MDS patients, a double-labeling was performed on plastic embedded marrow biopsy sections, to detect CD34 antigen with specific monoclonal antibody and apoptosis by in situ end labeling (ISEL) of fragmented DNA. Despite high overall apoptosis (56.2% +/- 18.4%), only an occasional CD34+ cell was found to be simultaneously labeled with ISEL. Finally, in the last group of 8 MDS patients, CD34+ cells were separated from CD34- cells on affinity column and cultured in serum containing medium for 4 hours. At 0- and 4-hour time points, ISEL was carried out to label apoptotic cells. In addition, a fluorometric assay was employed to estimate the activity of a proapoptotic enzyme, Caspase 3. Both the net increase in % ISEL labeled cells (apoptotic index or AI) and Caspase-3 activity were significantly lower in CD34+ cells as compared to CD34- cells (AI, 0.87% +/- 0.5% vs. 3.97% +/- 1.4%, n = 6, P = 0.028 and Caspase-3 Units/mg protein, 46.9 +/- 25.0 vs. 71.7 +/- 23.03, n = 5, P = 0.042, respectively). We conclude that when estimated in a total population of mononuclear cells, CD34+ cells and CD34- cells show comparable degrees of apoptosis. However, once separated the CD34+ fraction demonstrates lower propensity to undergo apoptosis, thereby suggesting the CD34- fraction as being a possible source for proapoptotic signaling.

Aged↗