Search PubMed⌕ Search

Biomedical subjects

V Smith

Publications and source records attributed to V Smith.

At least 37 records · Page 2Linked to original sources

The Manchester Child Attachment Story Task: relationship with parental AAI, SAT and child behaviour.

The Manchester Attachment Story Task (MCAST) is a new method for eliciting the internal working model (IWM) of attachment representations in children between 5 and 7 years. The instrument is described in the companion paper, 'A New Method of Evaluating Attachment Representations'. This paper reports initial findings on a non-clinical sample comparing the MCAST with concurrent maternal attachment representation, measures of child temperament and behaviour, and concurrent ratings on the Separation Anxiety Test (SAT). Ratings of disorganized attachment on the MCAST show association with Unresolved status on concurrent maternal Adult Attachment Interview (AAI) and with independent teacher ratings of classroom behaviour. Child temperament shows an effect on the style of engagement with the interview but not the attachment ratings. Possible alternative explanations for the phenomena seen are discussed, along with potential applications of the instrument and directions for future research.

Anxiety, Separation↗

Spondylometaphyseal dysplasia Sedaghatian type associated with lethal arrhythmia and normal intrauterine growth in three siblings.

Spondylometaphyseal dysplasia of the Sedaghatian type is a rare dysplasia, characterized by mild limb shortening, but lethal in the neonatal period. We describe three affected male siblings, the offspring of consanguineous parents. One was stillborn. Neonatal death was due to cardiac arrhythmia in two of the siblings. This report confirms the importance of cardiac pathology in this probably autosomal recessive disorder. This diagnosis should be excluded in any newborn with an arrhythmia as the clinical limb shortening may not be obvious.

Arrhythmias, Cardiac↗

Validation of the NPI-Q, a brief clinical form of the Neuropsychiatric Inventory.

The Neuropsychiatric Inventory (NPI) is a validated clinical instrument for evaluating psychopathology in dementia. The authors developed a brief questionnaire form of the NPI (NPI-Q), intended for use in routine clinical practice, and cross-validated it with the NPI in 60 Alzheimer's patients. Test-retest reliability of the NPI-Q was acceptable. The prevalence of analogous symptoms reported on the NPI and NPI-Q differed on average by 5%; moderate or severe symptom ratings differed by less than 2%. The NPI-Q provides a brief, reliable, informant-based assessment of neuropsychiatric symptoms and associated caregiver distress that may be suitable for use in general clinical practice.

Aged↗

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗

Endoscopic thoracoplasty and anterior spinal release in scoliotic deformity.

Severe rigid and complex deformities of the spine often require a first stage procedure to adequately mobilize the spine to provide adequate flexibility during the actual application of instrumentation for surgical correction. This first stage involves soft tissue releases and removal of intervertebral disks from the anterior spine. Exposure to the anterior spine has traditionally been accomplished through thoracotomy or a thoracolumbar incision. The open thoracotomy, however, has several disadvantages, such as post-thoracotomy pain, a large scar, and breathing difficulties. Since the first thoracoscopy at the beginning of this century, the procedure, at first limited by the available technology, has gradually gained more uses and favor among physicians. The last 10 years have seen significant improvement in optical technology and instrumentation. These advances have allowed the spine surgeon to begin performing anterior spinal releases using endoscopic techniques. These endoscopic techniques can carry the same efficacy as the open thoracotomy but less morbidity. Thoracoplasty, the resection of rib segments, is an excellent way to not only correct the convex rib deformities seen in scoliosis but it is also an excellent source of bone which can be used as a graft for fusion. Although traditionally, thoracoplasty has also been done through an open procedure, it can be performed endoscopically. This prospective study presents nine patients who underwent combined endoscopic anterior spinal release and thoracoplasty followed by same day posterior instrumentation and fusion for correction of their spinal deformities. All nine procedures were completed successfully endoscopically. It is our conclusion that in the hands of an experienced surgeon, the endoscopic technique is an excellent procedure providing the same efficacy as the open thoracotomy. There is however a learning curve associated with the procedure. In addition, a team approach in which the surgeon and an experienced anesthesiologist with experience with double lumen intubation and selective single lung ventilation and thoracoscopic surgery is crucial. Although there were no surgical complications related to the thoracoscopic technique one patient did require prolonged intubation postoperatively, which leads us to believe that single lung ventilation in and of itself is very demanding and each patient must be considered carefully prior to its undertaking.

Adolescent↗

Introduction of a new branchpoint in tetrapyrrole biosynthesis in Escherichia coli by co-expression of genes encoding the chlorophyll-specific enzymes magnesium chelatase and magnesium protoporphyrin methyltransferase.

The genes encoding the three Mg chelatase subunits, ChlH, ChlI and ChlD, from the cyanobacterium Synechocystis PCC6803 were all cloned in the same pET9a-based Escherichia coli expression plasmid, forming an artificial chlH-I-D operon under the control of the strong T7 promoter. When a soluble extract from IPTG-induced E. coli cells containing the pET9a-ChlHID plasmid was assayed for Mg chelatase activity in vitro, a high activity was obtained, suggesting that all three subunits are present in a soluble and active form. The chlM gene of Synechocystis PCC6803 was also cloned in a pET-based E. coli expression vector. Soluble extract from an E. coli strain expressing chlM converted Mg-protoporphyrin IX to Mg-protoporphyrin monomethyl ester, demonstrating that chlM encodes the Mg-protoporphyrin methyltransferase of Synechocystis. Co-expression of the chlM gene together with the chlH-I-D construct yielded soluble protein extracts which converted protoporphyrin IX to Mg-protoporphyrin IX monomethyl ester without detectable accumulation of the Mg-protoporphyrin IX intermediate. Thus, active Mg chelatase and Mg-protoporphyrin IX methyltransferase can be coupled in E. coli extracts. Purified ChlI, -D and -H subunits in combination with purified ChlM protein were subsequently used to demonstrate in vitro that a molar ratio of ChlM to ChlH of 1 to 1 results in conversion of protoporphyrin IX to Mg-protoporphyrin monomethyl ester without significant accumulation of Mg-protoporphyrin.

Chlorophyll↗

Five year results of LINAC radiosurgery for arteriovenous malformations: outcome for large AVMS.

PURPOSE: For radiosurgery of large arteriovenous malformations (AVMs), the optimal relationship of dose and volume to obliteration, complications, and hemorrhage is not well defined. Multivariate analysis was performed to assess the relationship of multiple AVM and treatment factors to the outcome of AVMs significantly larger than previously reported in the literature. METHODS AND MATERIALS: 73 patients with intracranial AVMs underwent LINAC radiosurgery. Over 50% of the AVMs were larger than 3 cm in diameter and the median and mean treatment volumes were 8.4 cc and 15.3 cc, respectively (range 0.4-143.4 cc). Minimum AVM treatment doses varied between 1000-2200 cGy (median: 1600 cGy). RESULTS: The obliteration rates for treatment volumes < 4 cc, 4-13.9 cc, and > or = 14 cc were 67%, 58%, and 23%, respectively. AVM obliteration was significantly associated with higher minimum treatment dose and negatively associated with a history of prior embolization with particulate materials. No AVM receiving < 1400 cGy was obliterated. The incidence of post-radiosurgical imaging abnormalities and clinical complications rose with increasing treatment volume. For treatment volumes > 14 cc receiving > or = 1600 cGy, the incidence of post-radiosurgical MRI T2 abnormalities was 72% and the incidence of radiation necrosis requiring resection was 22%. The rate of post-radiosurgical hemorrhage was 2.7% per person-year for AVMs with treatment volumes < 14 cc and 7.5% per person-year for AVMs > or = 14 cc. CONCLUSION: As AVM size increases, the dose-volume range for the optimal balance between successful obliteration and the risk of complications and post-radiosurgical hemorrhage narrows.

Adolescent↗

A multi-institutional analysis of complication outcomes after arteriovenous malformation radiosurgery.

PURPOSE: To better understand radiation complications of arteriovenous malformation (AVM) radiosurgery and factors affecting their resolution. METHODS AND MATERIALS: AVM patients (102/1255) who developed neurological sequelae after radiosurgery were studied. The median AVM marginal dose (Dmin) was 19 Gy (range: 10-35). The median volume was 5.7 cc (range: 0.26-143). Median follow-up was 34 months (range: 9-140). RESULTS: Complications consisted of 80/102 patients with evidence of radiation injury to the brain parenchyma (7 also with cranial nerve deficits, 12 also with seizures, 5 with cyst formation), 12/102 patients with isolated cranial neuropathies, and 10/102 patients with only new or worsened seizures. Severity was classified as minimal in 39 patients, mild in 40, disabling in 21, and fatal in 2 patients. Symptoms resolved completely in 42 patients for an actuarial resolution rate of 54% +/- 7% at 3 years post-onset. Multivariate analysis identified significantly greater symptom resolution in patients with no prior history of hemorrhage (p = 0.01, 66% vs. 41%), and in patients with symptoms of minimal severity: headache or seizure as the only sequelae of radiosurgery (p < 0.0001, 88% vs. 34%). CONCLUSION: Late sequelae of radiosurgery manifest in varied ways. Further long-term studies of these problems are needed that take into account symptom severity and prior hemorrhage history.

Adrenal Cortex Hormones↗

Initial cash/asset ratio and asset prices: an experimental study.

A series of experiments, in which nine participants trade an asset over 15 periods, test the hypothesis that an initial imbalance of asset/cash will influence the trading price over an extended time. Participants know at the outset that the asset or "stock" pays a single dividend with fixed expectation value at the end of the 15th period. In experiments with a greater total value of cash at the start, the mean prices during the trading periods are higher, compared with those with greater amount of asset, with a high degree of statistical significance. The difference is most significant at the outset and gradually tapers near the end of the experiment. The results are very surprising from a rational expectations and classical game theory perspective, because the possession of a large amount of cash does not lead to a simple motivation for a trader to bid excessively on a financial instrument. The gradual erosion of the difference toward the end of trading, however, suggests that fundamental value is approached belatedly, offering some consolation to the rational expectations theory. It also suggests that there is a time scale on which an evolution toward fundamental value occurs. The experimental results are qualitatively compatible with the price dynamics predicted by a system of differential equations based on asset flow. The results have broad implications for the marketing of securities, particularly initial and secondary public offerings, government bonds, etc., where excess supply has been conjectured to suppress prices.

Journal Article↗

Comparison of radiosurgery treatment modalities based on physical dose distributions.

PURPOSE: As a means of selecting the optimal stereotactic radiosurgery (SRS) treatment modality, a comparison of physical dose distributions to defined targets and nontarget brain tissue has been made for a group of test cases selected to represent a range of treatment-planning situations from small, nearly spherical volumes to large irregular volumes. METHODS AND MATERIALS: Plans were developed for each case using photon beams from the Leksell Gamma Unit (LGU), multiarc bremsstrahlung photon beams from a linear accelerator (linac) and proton beams, with the objective of encompassing the target as closely as possible with the prescription isodose line, and minimizing dosage to normal tissue within the bounds of standard clinical practice. Dose-volume histograms (DVHs) were calculated for target and for nontarget brain tissue and compared for the various modalities. RESULTS: In general, protons delivered less dosage to normal brain than other modalities for large and peripheral lesions and LGU plans were more successful at conforming to highly irregular shapes than conventional linac plans. CONCLUSIONS: Differences were observed to depend on treatment modality, target characteristics (shape, size and location), and the amount of effort expended on treatment planning and the time allotted for treatment implementation.

Astrocytoma↗

Comparison of radiosurgery treatment modalities based on complication and control probabilities.

PURPOSE: The relative efficacy of Gamma Knife, Linac, and Proton treatment modalities for stereotactic radiosurgery (SRS) was investigated on the basis of normal tissue complication probability (NTCP) and tumor control probability (TCP), calculated for representative test cases. METHODS AND MATERIALS: Five radiosurgery patient cases were selected to cover a range of treatment-planning situations from small spherical volumes to large irregular volumes. A target volume consisting of contours drawn on CT transverse slices was prepared for each case. Plans were developed using the three treatment modalities for each case, with the objective of encompassing the target as closely as possible with a prescription isodose line and minimizing dose to normal tissue, within the constraints of current clinical practice. Dose-volume histograms (DVH) were calculated for the target and for normal tissue, and these histograms were used to calculate NTCP and TCP values for each plan. RESULTS AND CONCLUSIONS: Differences in NTCP and TCP values were found to depend on treatment modality, size, shape, and location of the target, the amount of effort devoted to treatment planning, and the complexity of the plan.

Algorithms↗

A protocol for the pharmacologic treatment of major depression. A field test of a potential prototype.

BACKGROUND: Much attention is being given to developing clinical practice guidelines for management of mental health disorders. The aim of this study was to field test a prototype protocol for the pharmacologic treatment of Major Depression. METHOD: The protocol consisted of four, six week, treatment phases with critical choices in therapy defined by scores on the MADRS (Montgomery Asberg Depression Rating Scale). Observational data as collected on the behaviour of the protocol in terms of relevance, acceptability, ease of use and effectiveness. RESULTS: Effectiveness of the protocol was good for those patients who were retained within it, with three quarters of them attaining remission. However more than half of all patients dropped out-non attendance and adverse events being the most common reasons for this. CONCLUSION: The protocol for the treatment of Major Depression appeared relevant, easy to use and potentially effective. LIMITATION: Problems with non-adherence by both doctors and patients posed major challenges to the protocol's design. Such difficulties demonstrate the need to field test any proposed design as preconceptions about a protocol's performance may be misplaced. CLINICAL RELEVANCE: The protocol tested represents progress towards the goal of developing optimal strategies for the use of pharmacotherapeutic agents in the treatment of depression.

Adolescent↗

Lack of a role for MRP1 in platinum drug resistance in human ovarian cancer cell lines.

The level of expression of the multidrug resistance-associated protein (MRP1) in a panel of human ovarian carcinoma cell lines and their variants with acquired cisplatin resistance was determined using Western blotting. No overexpression of MRP1 was detected in any of the cell lines. In addition, we have transfected the MRP1 gene into an intrinsically cisplatin-resistant cell line SKOV3, previously shown to have elevated levels of glutathione (GSH). The MRP1-transfected line SKOV3-S2 was shown to be cross-resistant to doxorubicin, vincristine and etoposide but not to paclitaxel, vinblastine and platinum agents, such as cisplatin, JM216 [bis-acetato-ammine-dichloro-cyclohexylamine platinum (IV)] and AMD473 [cis-ammine dichloro (2-methyl-pyridine) platinum (II)]. No cross-resistance to any of the platinum agents was observed in a MRP1-overexpressing human lung cancer cell line with acquired doxorubicin resistance. Reduction of GSH levels (80-90%) by buthionine sulphoximine (BSO) produced significant potentiation in cisplatin sensitivity in the parental SKOV3, the vector-alone control SKOV3-puro and the MRP1-transfected line SKOV3-S2. The degree of sensitization was similar in all cell lines (1.6-fold). However, selective sensitization by BSO to vincristine was observed in the MRP1-transfected line (4.1-fold) but not in the vector control. No significant differences were observed in cisplatin accumulation in the SKOV3-puro and the SKOV3-S2 cells, although both these transfected lines accumulated significantly more than the parental line. Our results suggest that MRP1 does not play a significant role in platinum resistance in the human tumour cell lines investigated in this study.

ATP-Binding Cassette Transporters↗

Pediatric bilateral facial paralysis.

Bilateral facial paralysis is an unusual clinical entity that occurs in less than 1% of patients with facial paralysis. In children bilateral facial paralysis is even more rare, and establishing its etiology can be challenging. Four pediatric patients ranging in age from 3 to 17 years are presented who developed bilateral facial paralysis as a result of acute otitis media, Lyme disease, recurrent central nervous system leukemia, and acute disseminated encephalomyelitis. The diagnosis and treatment of pediatric bilateral facial paralysis are reviewed, as well as the pertinent literature.

Acute Disease↗

Malaria imported into the United Kingdom in 1996.

Virtually all malaria infections seen in the United Kingdom (UK) in recent years have been contracted overseas and imported into the UK, apart from two cases in 1976 due to imported infected mosquitoes and occasional cases of congenital or of transfusion

Journal Article↗

The nucleotide sequence of Saccharomyces cerevisiae chromosome IX.

Large-scale systematic sequencing has generally depended on the availability of an ordered library of large-insert bacterial or viral genomic clones for the organism under study. The generation of these large insert libraries, and the location of each clone on a genome map, is a laborious and time-consuming process. In an effort to overcome these problems, several groups have successfully demonstrated the viability of the whole-genome random 'shotgun' method in large-scale sequencing of both viruses and prokaryotes. Here we report the sequence of Saccharomyces cerevisiae chromosome IX, determined in part by a whole-chromosome 'shotgun', and describe the particular difficulties encountered in the random 'shotgun' sequencing of an entire eukaryotic chromosome. Analysis of this sequence shows that chromosome IX contains 221 open reading frames (ORFs), of which approximately 30% have been sequenced previously. This chromosome shows features typical of a small Saccharomyces cerevisiae chromosome.

Base Composition↗