Reduced embolic load during clinical cardiopulmonary bypass using a 20 micron arterial filter.

OBJECTIVE: To compare the efficiency of 20 and 40 µm arterial line filters during cardiopulmonary bypass for the removal of emboli from the extracorporeal circuit. METHODS: Twenty-four adult patients undergoing surgery were perfused using a cardiopulmonary bypass circuit containing either a 20 µm or 40 µm arterial filter (n = 12 in both groups). The Emboli Detection and Classification system was used to count emboli upstream and downstream of the filter throughout cardiopulmonary bypass. The mean proportion of emboli removed by the filter was compared between the groups. RESULTS: The 20 µm filter removed a significantly greater proportion of incoming emboli (0.621) than the 40 µm filter (0.334) (p=0.029). The superiority of the 20 µm filter persisted across all size groups of emboli larger than the pore size of the 40 µm filter. CONCLUSION: The 20 µm filter removed substantially more emboli than the 40 µm filter during cardiopulmonary bypass in this comparison.

Bad Obstetric History: A Prospective Study.

BACKGROUND: Death of an infant in utero or at birth has always been a devastating experience for the mother and of concern in clinical practice. Perinatal mortality remains a challenge in the care of pregnant women worldwide, particularly for those who had history of adverse outcome in previous pregnancies. To assess the risk factors and outcome of pregnancies in cases of bad obstetric history (BOH) and compare the results with control group, this study was undertaken. METHODS: A prospective study from 2003 to 2007 was carried out in 79 pregnancies having BOH (history of unexplained stillbirth/neonatal death, three or more consecutive abortions etc). Test group was analyzed in terms of age, gravida, parity, risk factors and outcome in terms of preterm delivery, stillbirth, mode of delivery, birth weight, pregnancy complications and fetal distress. These parameters were compared with a systematic, randomly selected sample from rest of the deliveries. Necessary advice and treatment was given in cases of hypothyroidism, hypertension, antiphospholipid antibody (APLA) syndrome, gestational diabetes and other risk factors. RESULT: There was significantly higher incidence of malpresentations, hypertension, APLA, cervical incompetence, preterm deliveries and caesarean section in test group (p< 0.05). In this study, only 47 (59.49%) women out of 79 in BOH group were identified to have possible factor responsible for pregnancy losses. In 32 (40.51%), no probable causes could be identified. Nine (11.39%) patients were identified with more than one risk factor. CONCLUSION: APLA, hypertension, malpresentation, cervical incompetence, preterm deliveries and caesarean section were found significantly more in BOH group. In a large percentage of pregnancies with BOH, the risk factors for adverse outcome were not identified but pregnancy outcome was generally good in subsequent pregnancies with optimal antenatal care and advice.

Maternal Factors for Low Birth Weight Babies.

BACKGROUND: Low birth weight is defined as the live births with less than 2.5 kg weight. It is a key determinant of infant survival, health and development. Low birth weight infants are at a greater risk of having a disability and for diseases such as cerebral palsy, visual problems, learning disabilities and respiratory problems. To reduce the low birth weight deliveries, we studied the maternal factors which adversely affect the fetus in utero and their impact on fetus. METHODS: A retrospective study was carried out on 40 low birth weight pregnancies out of 650 deliveries from July 2005 to Jun 2006. Maternal factors like age, parity, pre pregnancy body mass index, hemoglobin levels, bad obstetric history (history of stillbirth/neonatal death in previous pregnancies, three or more spontaneous consecutive abortions), pre eclampsia, fetal distress, mode of deliveries were studied. These results were compared with a random sample of 300 pregnant ladies taken from rest of the deliveries. Cases of multiple pregnancies and stillbirths were excluded. RESULT: We found that prepregnancy maternal body mass index (p<0.01 for BMI <20), unbooked status (p<0.01), pre eclampsia (p <0.01) and bad obstetric history (p<0.01) were the maternal factors which resulted in low birth weight babies in most of the cases. However in 10 (25%) cases, no contributory maternal factor was found. CONCLUSION: Prepregnancy maternal body mass index, unbooked status, pre eclampsia and bad obstetric history are significant maternal factors resulting in low birth weight babies.

Effect of Antenatal Expression of Breast Milk at Term in Reducing Breast Feeding Failures.

BACKGROUND: Though breast feeding is natural, during the first 2-3 days, when enough breast milk is not available with mother, she may introduce bottle feeding erroneously for improving nutrition to her baby. We studied the effect of antenatal expression of breast milk at term in reducing breast feeding failure as compared to conventional method of initiation of breast feeding. METHODS: A prospective study was carried out in 180 booked cases at term. Daily expression of breast milk at least once a day after 37 weeks of pregnancy was introduced in randomly selected 90 pregnant ladies. Prior examination was done to exclude any inverted or cracked nipples and appropriate treatment instituted. RESULT: The study group who expressed breast milk daily after 37 weeks did not find it difficult to initiate breast feeding after vaginal or cesarean delivery. Sufficient milk started flowing within half an hour of initiation of breast feeding in most 85 (94.4%) subjects of study group as compared to 63 (70%) patients of control group, which was statistically significant. There was no increase in any delivery complication. There were two partial breast feeding failures in control group but none in study group. CONCLUSION: Daily antenatal breast milk expression after 37 completed weeks of pregnancy significantly reduced the time for establishing full breast feeding and reduced breast feeding failures.

Thyroid hormone stimulation of extracellular signal-regulated kinase and cell proliferation in human osteoblast-like cells is initiated at integrin alphaVbeta3.

The aim of the present study was to examine whether triiodo-l-thyronine (T(3)) or l-thyroxine (T(4)) rapidly activated the mitogen-activated protein kinase (MAPK) intracellular signalling cascade in osteoblast-like cells and investigate whether this activation was initiated at the integrin alpha(V)beta(3) cell surface receptor. Using PCR and western blotting, the expression of integrin alpha(V)beta(3) mRNA and protein was demonstrated in the human osteoblast-like cell lines MG-63 and SaOS-2. The treatment of MG-63 cells with T(3) (10 nM) or T(4) (100 nM) for 10 min stimulated extracellular signal-regulated kinase activity (ERK, a component of the MAPK pathway) as determined by fluorescent immunocytochemistry and an immunocomplex activity assay (T(3) by 10.7-fold, P<0.01 and T(4) by 10.4-fold, P<0.01 compared with control). T(3) (10 nM) and T(4) (100 nM) also significantly stimulated thymidine incorporation into MG-63 cells by 2.3+/-0.7-fold (P<0.01) and 2.1+/-0.1-fold (P<0.05) respectively. To establish whether transient ERK activation via the integrin alpha(V)beta(3) cell surface receptor mediated these effects, MG-63 cells were pretreated for 30 min with the specific MAPK kinase inhibitor, U0126 (1 microM), or an anti-integrin alpha(V)beta(3)-blocking antibody. Both pretreatments significantly inhibited T(3)- and T(4)-stimulated ERK activation and abolished T(3)-stimulated thymidine incorporation (P<0.01). T(4)-stimulated incorporation was significantly inhibited from 2.1- to 1.3-fold above control (P<0.05). Thus, our results suggest that T(3) and T(4) rapidly stimulate ERK activation in MG-63 cells via integrin alpha(V)beta(3) and that one functional effect of this ERK activation is increased DNA synthesis.

Daily Fetal Movement Count Chart : Reducing Perinatal Mortality in Low Risk Pregnancy.

BACKGROUND: A reduction or cessation of fetal movements (FMs) is frequently reported by pregnant women resulting in anxiety and concern. Formal counting of FMs by the pregnant woman could possibly identify the fetuses at risk. METHODS: A prospective study was carried out over 500 booked cases after introducing daily fetal movement count (DFMC) Chart in the ninth month of pregnancy. Prior ultrasound (USG) was done in all cases. DFMC chart was used to record number of fetal movements perceived by patient for one hour after food (breakfast, lunch, dinner). Fetal movements were considered satisfactory if the count was three or more on each occasion. RESULT: During the study period, no fetus was lost after introduction of DFMC chart in the 250 cases that were given DFMC chart and delivered in our hospital (Nil perinatal mortality). This was compared with 250 booked cases that were not given DFMC chart but had normal ultrasound done after completion of eight months of pregnancy and followed up. Five intrauterine deaths occurred in the ninth month in control group (2% perinatal mortality). In the DFMC chart group, 15 patients were admitted with decreased fetal movements. Out of these, 12 were discharged after monitoring for three days and three cases were delivered. CONCLUSION: DFMC chart in ninth month of pregnancy helps in identifying at risk fetus in low risk pregnancies in absence of any other adverse factors necessitating early delivery.

Nuchal Cord : A Retrospective Analysis.

BACKGROUND: The nuchal cord is often blamed for problems that are encountered during delivery and is often cited as a major cause of fetal distress and perinatal mortality. However, the actual significance of nuchal cord on the outcome of an infant is controversial. A retrospective study was done to investigate the actual frequency of nuchal cords encountered in a hospital setting and to determine its effect on an infant as it passes through the birth canal and immediately after delivery. METHODS: A retrospective study was carried out in 350 deliveries (out of total 367 deliveries) including 65 cases of nuchal cord from July to December 2005. Nuchal cord group was divided into loose nuchal cord (cord could easily be uncoiled before delivery of the newborn) group and tight nuchal cord (cord was needed to be clamped and cut before delivery) group. The mode of delivery, complications and fetal outcome of nuchal cord groups was compared with rest of the deliveries. Seventeen cases (including three cases of nuchal cord) having complications as intrauterine growth retardation, oligohydramnios (AFI <5), antepartum haemorrhage, severe pregnancy induced hypertension and maternal medical complications were excluded. RESULT: We found that the loose nuchal cord group did not have any significant difference in mode of delivery or fetal outcome as compared to control group however the group having tight cord around the neck had significantly higher proportion of fetal distress and low Apgar scores at one minute. CONCLUSION: Loose nuchal cord doesn't increase the chances of cesarean delivery whereas tight cord around the neck may result in lower Apgar scores at one minute and increased incidence of fetal distress.

Cholestasis of Pregnancy : A Prospective Study.

BACKGROUND: Intrahepatic cholestasis of pregnancy (ICP) typically occurs during the last trimester of gestation. The most accurate marker for diagnosis and follow-up of ICP is increased total bile acid levels (above 11.0 micro mol/L) [1]. ICP is a benign disease with no consequences to the mother but it is associated with an increased rate of fetal morbidity and mortality. METHOD: A prospective study was carried out in 1500 deliveries which included 27 cases of ICP. The mode of delivery, complications and fetal outcome of intrahepatic cholestasis group were compared with rest of the deliveries. Cases having pruritic lesions of skin, viral hepatitis, gall stones, autoimmune liver diseases were excluded. Random selection of 300 pregnancies in the control group was done and their liver function tests were carried out for comparison. All the patients with cholestasis of pregnancy were treated with ursodeoxycholic acid. RESULT: The levels of the aminotransferases and alkaline phosphatase levels rose significantly (p < 0.05) in the study group. Cholestatic group did not have any significant difference in mode of delivery or fetal outcome from the control group. The patients in the study group were treated with ursodeoxycholic acid with significant relief in symptoms (p < 0.01), while improvement in serum bilirubin levels, alkaline phosphatase levels and aminotransferases levels were not statistically significant. CONCLUSION: In absence of serum bile acids levels, alkaline phosphatase and aminotransferases levels may help in diagnosis and management of cholestasis of pregnancy. Ursodeoxycholic acid treatment is effective in reducing the pruritus.

Towards understanding the schizophrenia code: an expanded convergent functional genomics approach.

Identifying genes for schizophrenia through classical genetic approaches has proven arduous. Here, we present a comprehensive convergent analysis that translationally integrates brain gene expression data from a relevant pharmacogenomic mouse model (involving treatments with a psychomimetic agent - phencyclidine (PCP), and an anti-psychotic - clozapine), with human genetic linkage data and human postmortem brain data, as a Bayesian strategy of cross validating findings. Topping the list of candidate genes, we have three genes involved in GABA neurotransmission (GABRA1, GABBR1, and GAD2), one gene involved in glutamate neurotransmission (GRIA2), one gene involved in neuropeptide signaling (TAC1), two genes involved in synaptic function (SYN2 and KCNJ4), six genes involved in myelin/glial function (CNP, MAL, MBP, PLP1, MOBP and GFAP), and one gene involved in lipid metabolism (LPL). These data suggest that schizophrenia is primarily a disorder of brain functional and structural connectivity, with GABA neurotransmission playing a prominent role. These findings may explain the EEG gamma band abnormalities detected in schizophrenia. The analysis also revealed other high probability candidates genes (neurotransmitter signaling, other structural proteins, ion channels, signal transduction, regulatory enzymes, neuronal migration/neurite outgrowth, clock genes, transcription factors, RNA regulatory genes), pathways and mechanisms of likely importance in pathophysiology. Some of the pathways identified suggest possible avenues for augmentation pharmacotherapy of schizophrenia with other existing agents, such as benzodiazepines, anticonvulsants and lipid modulating agents. Other pathways are new potential targets for drug development. Lastly, a comparison with our earlier work on bipolar disorder illuminates the significant molecular overlap between schizophrenia and bipolar disorder.

Female genital tract morbidity and sexual function following vaginal delivery or lower segment caesarean section.

A total of 208 women were assessed 2 years' post-delivery to record the prevalence of subjective urinary and faecal incontinence, incontinence of flatus, dyspareunia, subjective depression and sexual satisfaction. This was correlated with mode of delivery. A sample population was selected from the Cardiff Birth Survey Database, in accordance with strict inclusion and exclusion criteria. Each woman was invited to complete and return a postal questionnaire addressing symptoms of pelvic floor dysfunction. There was a significant decrease in sexual satisfaction scores in women who underwent vaginal delivery in comparison with those who underwent elective caesarean section at 2 years follow-up. There was also a significant increase in the prevalence of urinary incontinence, incontinence of flatus, dyspareunia and subjective depression in women who underwent vaginal delivery.

Convergent functional genomics: a Bayesian candidate gene identification approach for complex disorders.

Identifying genes involved in complex neuropsychiatric disorders through classic human genetic approaches has proven difficult. To overcome that barrier, we have developed a translational approach called Convergent Functional Genomics (CFG), which cross-matches animal model microarray gene expression data with human genetic linkage data as well as human postmortem brain data and biological role data, as a Bayesian way of cross-validating findings and reducing uncertainty. Our approach produces a short list of high probability candidate genes out of the hundreds of genes changed in microarray datasets and the hundreds of genes present in a linkage peak chromosomal area. These genes can then be prioritized, pursued, and validated in an individual fashion using: (1) human candidate gene association studies and (2) cell culture and mouse transgenic models. Further bioinformatics analysis of groups of genes identified through CFG leads to insights into pathways and mechanisms that may be involved in the pathophysiology of the illness studied. This simple but powerful approach is likely generalizable to other complex, non-neuropsychiatric disorders, for which good animal models, as well as good human genetic linkage datasets and human target tissue gene expression datasets exist.

Exogenous expression of glucagon-like peptide 1 receptor and human insulin in AtT-20 corticotrophs confers cAMP-mediated gene transcription and insulin secretion.

The insulinotrophic effects of glucagon-like peptide 1 (GLP-1) are mediated by its seven-transmembrane receptor (GLP-1R) in pancreatic beta-cells. We have transiently transfected the GLP-1R and a proopiomelanocortin (POMC) promoter-driven human preproinsulin gene vector (pIRES) into the AtT-20 pituitary corticotrophic cell line, to investigate the possibility of creating a regulated, insulin-expressing cell line. Receptor expression was confirmed by RT-PCR and functionality was demonstrated by measuring changes in cAMP levels in response to GLP-1. Rapid (5 min) stimulation of cAMP production was observed with 100 nM GLP-1, 24 h after transfection of 2 microg GLP-1R DNA. AtT-20 cells co-transfected with GLP-1R and human glycoprotein hormone alpha-subunit or rat POMC promoters revealed GLP-1-stimulated cAMP activation of transcription. Co-transfection of the pIRES vector with the GLP-1R resulted in GLP-1-stimulated activation of POMC promoter-driven preproinsulin gene transcription but insulin secretion was not detected. However, using an adenoviral expression system to infect AtT-20 cells with GLP-1R and the preproinsulin gene (including 120 bp of its own promoter) resulted in a 6.4 +/- 0.6-fold increase in cAMP and a 4.9 +/- 0.8-fold increase in insulin secretion in response to 100 nM GLP-1. These results demonstrate, for the first time, functional GLP-1R-mediated preproinsulin gene transcription and secretion in a transplantable cell line.

The activity of letrozole in patients with advanced or recurrent endometrial cancer and correlation with biological markers--a study of the National Cancer Institute of Canada Clinical Trials Group.

A multicenter phase II trial was conducted to define the activity of letrozole in postmenopausal women with recurrent or advanced endometrial carcinoma, who had no more than one prior line of progestins and never had chemotherapy (except adjuvant). Archival paraffin-embedded tumor samples were retrieved to determine the expression level of estrogen (ER) and progesterone receptor (PgR), p53, HER-2, bcl-2 and PTEN protein, and phosphorylation status of protein kinase B (PKB/Akt). Thirty-two eligible patients were treated with letrozole at 2.5 mg daily continuously, of whom 10 (31%) had prior progestins. Of the 28 patients evaluated for response, one complete and two partial responses were noted; overall response was 9.4% (95% confidence interval 2-25%). Eleven patients had stable disease for a median duration of 6.7 months (range 3.7-19.3 months). Amongst 22 patients who had tumor blocks available, the proportion showing positive expression of the following markers includes: PgR (86%), ER (86%), PTEN (82%), phosphorylated PKB/Akt (59%), bcl-2 (45%), p53 (32%), and HER-2 (0%). None of these markers correlated with response to letrozole or disease progression. In conclusion, letrozole is well tolerated but has little overall activity in this cohort of women with endometrial cancer.

A flow cytometric assay for global estimation of tyrosine phosphorylation associated with capacitation of spermatozoa from two marsupial species, the tammar wallaby (Macropus eugenii) and the brushtail possum (Trichosurus vulpecula).

The phosphorylation of tyrosine residues in cellular proteins is a major signal transduction event during sperm capacitation. In this study protein phosphorylation was monitored using a fluorescein isothiocyanate (FITC)-labeled antiphosphotyrosine monoclonal antibody and a flow cytometric procedure optimized for sperm. Using this technique, the correlation between tyrosine phosphorylation and sperm capacitation was examined in two marsupial species, the brushtail possum and the tammar wallaby and compared with that of ram spermatozoa. The levels of tyrosine phosphorylation in sperm from all three species were increased by the addition of cyclic AMP (cAMP) and vandate, a phosphotyrosine phosphatase inhibitor and were decreased by the addition of the phosphotyrosine kinase inhibitor, staurosporine. Oviductal conditioned media (CM) induced a progressive increase in tyrosine phosphorylation in both marsupial species and also induced morphological transition from a streamlined to a 'T'-shape configuration in brushtail possum spermatozoa but not in tammar wallaby spermatozoa. Transition to the 'T'-shape orientation associated with capacitation in marsupial spermatozoa was observed by 2 h of incubation in both species when tyrosine phosphorylation was increased by higher levels of cAMP i.e. 5 mM dibutyryl cAMP plus 3 mM pentoxyphylline. Thus the tyrosine phosphorylation trigger with CM may differ in these two marsupial species. Ram sperm tyrosine phosphorylation could be increased by addition of lower levels of cAMP (1 mM). These results support the finding that tyrosine phosphorylation is associated with sperm capacitation in marsupials. Similar results were obtained by using SDS PAGE/Western blot analysis of tyrosine phosphorylation in the brushtail possum spermatozoa. The specificity, efficiency and sensitivity of the procedure described here make it applicable for routine assessment of capacitation in large numbers of samples and in other species.

Delineation of brain metastases on CT images for planning radiosurgery: concerns regarding accuracy.

Conformal radiotherapy requires confidence that the images used for target delineation accurately reflect the pathological dimensions of the target. Radiosurgery, which is a conformal radiotherapy technique, is often used to treat brain metastases. The images of brain metastases can be affected by the method of image acquisition. A prospective study was undertaken to evaluate the effect of delay on CT images of brain metastases selected for radiosurgical treatment. A median delay from contrast administration of 65 min resulted in an increase in the volume of the metastases in 86% of cases when compared with the volumes of the same metastases determined from CT images acquired immediately following the administration of contrast medium. The magnitude of the increase in volume was sufficient to cause radiosurgery planners to select larger collimator sizes for radiosurgery plans based on the delayed CT images in 92% of cases. No significant intraobserver or interobserver variation was found in the group of radiosurgery planners. Differences in image acquisition may account in part for the differences in local control reported in the radiosurgical treatment of brain metastases.

Absence of pituitary adenylate cyclase-activating polypeptide-stimulated transcription of the human glycoprotein alpha-subunit gene in LbetaT2 gonadotrophs reveals disrupted cAMP-mediated gene transcription.

Hormone regulation of anterior pituitary expression of the common glycoprotein hormone alpha-subunit (alphaGSU) is mediated by multiple response elements residing in the first -435 bp of the human promoter. In rat pituitary cells and mouse alphaT3-1 precursor gonadotrophs, the human alphaGSU promoter is strongly responsive to activators of the adenylyl cyclase/cAMP pathway, such as the hypothalamic releasing hormone, pituitary adenylate cyclase-activating polypeptide (PACAP) and forskolin (an adenylyl cyclase activator). However, the role of PACAP and cAMP in regulating alphaGSU transcription in the more differentiated LbetaT2 gonadotroph is unclear. Here, we investigate the regulation of the human alphaGSU promoter by PACAP and forskolin in LbetaT2 and alphaT3-1 gonadotrophs. PACAP failed to stimulate alphaGSU promoter activity or cAMP production in LbetaT2 cells, in marked contrast to alphaT3-1 cells. LbetaT2 gonadotrophs expressed extremely low levels of any PACAP type 1 receptors (PAC(1)-R) isoform by RT-PCR and lacked PAC(1)-R by radioligand binding. Forskolin stimulated the alphaGSU promoter in LbetaT2 cells, but by less than 30% of the response seen in alphaT3-1 gonadotrophs. This blunted cAMP transcriptional effect was not due to different levels of cAMP generation, or altered expression of the cAMP target proteins CREB, Akt, CBP or ICER. However, only LbetaT2 cells showed detectable expression of the protein kinase A type IIalpha regulatory subunit. Binding of activating transcription factor-2 and phosphorylated CREB to the consensus CRE was observed in both LbetaT2 and alphaT3-1 gonadotrophs, yet forskolin failed to stimulate either CRE- or CREB-mediated transcription in LbetaT2 cells. Collectively, these data demonstrate the lack of functional PACAP receptors in LbetaT2 gonadotrophs, and a pronounced attenuation in the responsiveness of this differentiated gonadotroph cell line to cAMP stimulus.

Ionic calcium levels in oviduct explant-conditioned media from an Australian marsupial, the brushtail possum (Trichosurus vulpecula) and its relevance to in vitro fertilization.

Gametes from the brushtail possum (Trichosurus vulpecula), an Australian marsupial, require exposure to oviductal cells and/or their secretions before sperm binding and penetration of the zona pellucida can occur. Sperm-egg fusion, the next critical step in fertilization has not previously been reported in vitro. Here we describe the refinement of an oviduct epithelial cell (OEC) explant culture system using two different media to obtain in vitro sperm-egg fusion in the brushtail possum for the first time. Conditioned media from OEC explant cultures were supplemented with either 1% fetal calf serum (FCS) or 1 mg/ml polyvinyl alcohol and used for co-culture of epididymal sperm and superovulated eggs. Under these conditions zona penetration rates varied from 0 to 46% and sperm-egg fusion from 0 to 20%. Analysis of explant conditioned media indicated that qualitative and quantitative differences between batches could account, at least partially, for the large variability in zona penetration rates. Conditioned media that contained approximately 1 mM of ionic calcium were most effective for achieving sperm capacitation, zona binding, and penetration and sperm-egg fusion. The reorientation of the sperm head to T-shape, an indicator of capacitation in the brushtail possum, was closely linked with the concentration of calcium present in vitro.

Effect of respiratory gating on reducing lung motion artifacts in PET imaging of lung cancer.

Positron emission tomography (PET) has shown an increase in both sensitivity and specificity over computed tomography (CT) in lung cancer. However, motion artifacts in the 18F fluorodioxydoglucose (FDG) PET images caused by respiration persists to be an important factor in degrading PET image quality and quantification. Motion artifacts lead to two major effects: First, it affects the accuracy of quantitation, producing a reduction of the measured standard uptake value (SUV). Second, the apparent lesion volume is overestimated. Both impact upon the usage of PET images for radiation treatment planning. The first affects the visibility, or contrast, of the lesion. The second results in an increase in the planning target volume, and consequently a greater radiation dose to the normal tissues. One way to compensate for this effect is by applying a multiple-frame capture technique. The PET data are then acquired in synchronization with the respiratory motion. Reduction in smearing due to gating was investigated in both phantoms and patient studies. Phantom studies showed a dependence of the reduction in smearing on the lesion size, the motion amplitude, and the number of bins used for data acquisition. These studies also showed an improvement in the target-to-background ratio, and a more accurate measurement of the SUV. When applied to one patient, respiratory gating showed a 28% reduction in the total lesion volume, and a 56.5% increase in the SUV. This study was conducted as a proof of principle that a gating technique can effectively reduce motion artifacts in PET image acquisition.

Cone-beam CT with megavoltage beams and an amorphous silicon electronic portal imaging device: potential for verification of radiotherapy of lung cancer.

We investigate the potential of megavoltage (MV) cone-beam CT with an amorphous silicon electronic portal imaging device (EPID) as a tool for patient position verification and tumor/organ motion studies in radiation treatment of lung tumors. We acquire 25 to 200 projection images using a 22 x 29 cm EPID. The acquisition is automatic and requires 7 minutes for 100 projections; it can be synchronized with respiratory gating. From these images, volumetric reconstruction is accomplished with a filtered backprojection in the cone-beam geometry. Several important prereconstruction image corrections, such as detector sag, must be applied. Tests with a contrast phantom indicate that differences in electron density of 2% can be detected with 100 projections, 200 cGy total dose. The contrast-to-noise ratio improves as the number of projections is increased. With 50 projections (100 cGy), high contrast objects are visible, and as few as 25 projections yield images with discernible features. We identify a technique of acquiring projection images with conformal beam apertures, shaped by a multileaf collimator, to reduce the dose to surrounding normal tissue. Tests of this technique on an anthropomorphic phantom demonstrate that a gross tumor volume in the lung can be accurately localized in three dimensions with scans using 88 monitor units. As such, conformal megavoltage cone-beam CT can provide three-dimensional imaging of lung tumors and may be used, for example, in verifying respiratory gated treatments.

Role of physiological lung exclusion in difficult lung resections for massive hemoptysis and other problems.

OBJECTIVES: Pulmonary tuberculosis and bronchiectasis are the major causes of massive hemoptysis in developing countries. Lung resection remains the surgical treatment of choice. This may not always be possible and may even be hazardous in some patients due to fibrosis and dense vascular adhesions between the lung and the chest wall. This leads to marked blood loss and control of hilar vessels becomes dangerous. METHODS: A series of 20 cases is described here. Nineteen presented with massive hemoptysis where control of bleeding was obtained by physiological lung exclusion. One patient had traumatic left main bronchus transection not suitable for repair or resection. Physiological lung exclusion was performed by surgical interruption of the bronchus and pulmonary artery of the involved lobe or lung, keeping pulmonary veins intact. RESULTS: Hemoptysis could be controlled in all these patients without any significant morbidity. There was no mortality. There was no postoperative empyema and recurrence of hemoptysis on long-term follow-up. No patient required anatomical lung resection later on. CONCLUSIONS: Physiological lung exclusion is a safe and effective method for control of massive hemoptysis in cases where lung resection is technically hazardous or difficult. This should be kept as an alternative or adjunct to anatomical lung resection.