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A J Martin

Publications and source records attributed to A J Martin.

At least 37 records · Page 2Linked to original sources
PubMed2001

Ultrastructural examination is essential for diagnosis of papillary meningioma.

AIMS: Papillary meningioma is a rare meningeal tumour. To date only a few cases have been reported and their immunohistochemical features have not been fully documented. METHODS AND RESULTS: A 49-year-old woman presented with a 2-month history of headaches and memory disturbance. CT and MRI imaging showed an enhancing pineal mass with extension into the occipital lobes and invasion of the splenium. At surgery, the tumour was found to be tough and vascular with a well-defined capsule. No recurrence was noted 19 months after the operation. In another case a 44-year-old woman was admitted with 1-month history of headaches, poor memory, imbalance and diplopia. CT scan showed a large hyperdense, uniformly, enhancing mass within the middle cranial fossa at the petrous ridge. The tumour recurred 19 and 25 months after first resection. The histology of both tumours was similar. The neoplasms contained polygonal cells with a moderate amount of cytoplasm, rounded regular nuclei and distinct cell borders. The cells were arranged radially around the blood vessels (perivascular pattern) and a papillary pattern was seen only focally. Mitotic figures were moderately frequent. Immunohistochemistry showed that both tumours were immunoreactive to vimentin and NSE, whereas GFAP, CAM5.2, EMA, S100 protein and synaptophysin were negative. Electron microscopy revealed interdigitating cell processes, desmosomes and intermediate filaments. CONCLUSIONS: The histological and immunohistochemical features of these two tumours are complex and difficult to interpret. Although papillary meningiomas were considered in our initial differential diagnosis, the final conclusion was possible only when the ultrastructural features were revealed.

Biopsy↗
PubMed2001

Brain biopsy sampling by using prospective stereotaxis and a trajectory guide.

OBJECT: The authors describe their initial results obtained using a skull-mounted trajectory guide for intraoperative magnetic resonance (MR) imaging-guided brain biopsy sampling. The device was used in conjunction with a new methodology known as prospective stereotaxis for surgical trajectory alignment. METHODS: Between January 1999 and March 2000, 38 patients underwent 40 brain biopsy procedures in which prospective stereotaxis was performed with the trajectory guide in a short-bore 1.5-tesla MR imager. In most cases, orthogonal T2-weighted half-Fourier acquisition single-shot turbo spin-echo (HASTE) images were used to determine the desired trajectory and align the device. The surgical trajectory was defined as a line connecting three points: the target, pivot, and alignment stem points. In all cases, surgical specimens were submitted for frozen section and pathological examination. Postoperative turbofluid-attenuated inversion-recovery and gradient-echo images were obtained to exclude the presence of hemorrhage. Trajectory determination and alignment was simple and efficient, requiring less than 5 minutes. Confirmatory HASTE images were obtained along the biopsy needle as it was being advanced or after reaching the target. All biopsy procedures yielded diagnostic tissue. One patient with a lesion near the motor strip experienced a transient hemiparesis of the hand related to passage of the biopsy needle, and another sustained a fatal postoperative myocardial infarction. No patient suffered a clinically significant or radiologically visible hemorrhage. CONCLUSIONS: In combination with prospective stereotaxis, the trajectory guide provided a safe and accurate way to perform brain biopsy procedures.

Adolescent↗
PubMed2001

Spinal meningioma after treatment for Hodgkin disease. Case report.

Long-term survivors of Hodgkin disease may develop second primary tumors caused by the mutagenic effects of radio- and chemotherapy. The authors describe the case of a 35-year-old woman who presented with an unusual meningioma of the cervical spine 9 years after undergoing combined-modality treatment for Hodgkin disease. To the authors' knowledge, this is the first report of spinal meningioma as a complication of such therapy. Whereas radiation-induced intracranial meningiomas are well described in the literature, treatment-induced meningiomas of the spine have not been widely recognized.

Adult↗
PubMed2001

Preliminary assessment of turbo spectroscopic imaging for targeting in brain biopsy.

BACKGROUND AND PURPOSE: Brain biopsy remains an integral and necessary component in the diagnosis of brain lesions. We assessed the ability of turbo spectroscopic imaging (TSI) to provide a physiologically based target for tissue sampling. METHODS: TSI was performed in 26 anesthetized patients immediately before MR-guided brain biopsy. In 10 patients, single-voxel spectroscopy was performed on the TSI-indicated target and correlated with the TSI findings. Biopsy samples were taken from the imaging and spectroscopically defined target(s) under MR guidance, and pathologic findings were compared with preoperative spectra. RESULTS: TSI alone provided a definitive target based on a region of elevated choline in 17 of 21 patients in whom a neoplasm was confirmed. The remaining four neoplasms exhibited relatively low metabolic levels and were difficult to distinguish from the five cases of radiation necrosis seen in this study. TSI findings were in qualitative agreement with those obtained at single-voxel spectroscopy, although TSI spectra exhibited more contamination. Quantitative spectral analysis of TSI data is limited by low spectral resolution. CONCLUSION: TSI is helpful for determining an appropriate biopsy target in heterogeneous lesions. Coupling TSI targeting with conventional imaging and intraoperative confirmation of needle positioning resulted in a 100% diagnostic success rate and increased the clinician's confidence in the histologic findings.

Adolescent↗
PubMed2001

Perfusion MR neuroimaging in patients undergoing balloon test occlusion of the internal carotid artery.

BACKGROUND AND PURPOSE: We sought to investigate whether the combination of conventional, diffusion-weighted, and perfusion-weighted MR imaging increases the diagnostic accuracy of balloon test occlusion of the internal carotid artery. We describe perfusion anomalies and patterns of enhancement seen in areas of altered brain perfusion during MR-monitored temporary balloon occlusion of the internal carotid artery. METHODS: Nine patients underwent balloon occlusion testing under standard angiographic conditions with continuous clinical and EEG monitoring. One patient who failed the test by clinical criteria underwent an external carotid to internal carotid bypass operation, followed by a repeat balloon test occlusion, thereby bringing the total number of procedures to 10. Patients were further imaged at 1.5 T with perfusion- and diffusion-weighted imaging as well as with conventional noncontrast and contrast-enhanced turbo fluid-attenuated inversion recovery (FLAIR) and T1-weighted sequences. RESULTS: Seven of 10 patients who tolerated unilateral carotid test occlusion without adverse clinical neurologic or EEG changes exhibited delayed first-pass transit of contrast material through the affected cerebral hemisphere, indicative of altered perfusion without significant concurrent cerebral blood flow or blood volume changes. Four of these patients and both symptomatic patients showed pial or subarachnoid contrast staining in areas of altered perfusion without abnormalities on diffusion-weighted images. CONCLUSION: Our findings indicate that MR perfusion-weighted imaging is safe and easily accomplished in a high-field-strength magnet and that contrast-enhanced turboFLAIR imaging may provide clinically useful MR imaging evidence of abnormal cerebral blood flow and subclinical ischemia.

Adult↗
PubMed2000

Hyponatremia.

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Diagnosis, Differential↗
PubMed2000

Association between parental perception of children's vulnerability to illness and management of children's asthma.

This study examined the relationship between asthma management strategies used by parents and parental perception of children's vulnerability to illness. Home interviews were conducted with 101 parents of children previously hospitalized with asthma. The child vulnerability scale (CVS) was employed to assess parents' perception of their children's vulnerability to illness. The asthma severity index (ASI) was used to measure the frequency and intensity of asthma symptoms experienced by children in the preceding 12 months. Five markers of parental asthma management were assessed: (i) school absences; (ii) visits to the general practitioner (GP); (iii) visits to the emergency room (ER); (iv) hospitalizations; and (v) whether children are using a regular preventer. After controlling for the frequency and intensity of children's asthma symptoms, parents who perceived that their children were more vulnerable to medical illness were significantly more likely to keep their children home from school (P = 0.01), were more likely to take their children to the GP for acute asthma care (P = 0.02), and were more likely to be giving their children regular preventer medication (P = 0.02). In contrast, the use of tertiary pediatric care services was not significantly associated with parental perceptions of their children's vulnerability. The results suggest that parental attitudes and beliefs about the vulnerability of their children to illness were associated with greater use of GP services by parents and more frequent school absences for children. The use of hospital services by parents appeared to be more strongly associated with the actual level of children's asthma symptoms than their vulnerability to illness.

Absenteeism↗
PubMed2000

Effects of birthweight and oxygen supplementation on lung function in late childhood in children of very low birth weight.

Impaired respiratory function has been found frequently in ex-premature children, but it is unclear which specific factors influence this impairment the most. The aim of this study was to determine the importance of the contributions of birth weight, gestational age, neonatal respiratory disease, and its treatment on subsequent childhood lung function at age 11 years in a cohort of children of very low birth weight (VLBW; </=1,500 g). Detailed clinical histories were recorded, and lung function was measured in 60% (102 children) of surviving VLBW infants born 1981/1982, and compared with 82 matched control children (birth weight >2,000 g) of similar age. VLBW children were shorter and lighter than controls (P < 0.0001) at 11 years of age, and had reduced expiratory flows (P < 0.00001) and forced vital capacities (P < 0.001). The residual volume to total lung capacity ratio (RV/TLC ratio) was increased (P < 0.00001), while total lung capacity (TLC) remained unchanged. Those with bronchopulmonary dysplasia (BPD) had the lowest mean expiratory flows. Males had lower expiratory flows than females. On univariate analysis, gestational age by itself accounted for 8.8% of the explained variance in FEV(1) at 11 years of age, but birth weight accounted for 16% on its own; both together accounted for a further 0.2% (16.2%), suggesting that the latter was the dominant factor. On multivariate analysis, the contribution of birth weight and gestational age was small, and the best predictors at 11 years of age, which together explained 43.4% of the total variance in FEV(1), were log days of supplemental oxygen (9.6%) and a reported history of asthma (10.8%). For FEF(25-75), these predictors explained 7.2% and 13.4%, respectively, of the total explained variance of 40.6%. The relation between neonatal oxygen supplementation and childhood FEV(1) was such that up to 20 days of supplemental oxygen had little effect on subsequent FEV(1) at 11 years of age, but each additional week of supplemental oxygen after that time was associated with a progressive reduction in FEV(1) of 3%. These data confirm the significant role of supplemental oxygen in the neonatal period and a history of asthma on the subsequent reduction of expiratory flows in VLBW children. Birth weight was a more important prenatal factor than gestational age, but both were of lesser predictive significance than either supplemental oxygen or a reported history of asthma.

Asthma↗
PubMed2000

Effect of immediate versus slow intrauterine reduction of congenital diaphragmatic hernia on lung development in the sheep: a morphometric analysis of term pulmonary structure and maturity.

The incidence of congenital diaphragmatic hernia (CDH) is 1:1,200-5, 000, and the condition is associated with high mortality and morbidity attributed principally to associated pulmonary hypoplasia. One treatment approach has been for intrauterine intervention to induce lung growth to a sufficient level to allow survival at birth. Repair of the hernia in utero has been attempted, using a method of immediate reduction and repair of the hernia (patch) compared to a slow reduction method using a silastic "silo" sewn over the diaphragm defect to contain the hernial contents. In animal studies, this second method has been associated with lower fetal morbidity and mortality. This study, utilizing the sheep model of CDH, focuses on analysis of lung structural development and maturation, comparing the efficacy of the immediate vs. slow methods of hernial repair in preventing/reversing pulmonary hypoplasia. We hypothesized that: a) Both the immediate (patch) and slow (silo) methods of hernia repair performed in the lamb model of CDH will stimulate lung growth and structural development and restore lung structure and maturity towards normal levels by term gestation; b) Effects will be detectable by morphometric measurement of the following parameters: lung volume; parenchyma to nonparenchyma tissue ratio; volume density of connective tissue in nonparenchyma; gas exchange tissue to airspace ratio; gas exchange surface area; capillary loading; alveolar/airspace density; and alveolar perimeter; c) Effects will be seen in all lobes of the lung; and d) There will be no significant difference in lung size or structural parameters between the two groups. Forty-four pregnant ewes were allocated randomly to one of four groups. Fetal lambs in three groups (n = 36) underwent CDH creation at days 72-74 of gestation. Of surviving lambs showing an adequate hernia, 9 were not operated on further, 11 underwent "repair" using a silastic chimney around the hernial contents (slow reduction), and 11 underwent "repair" by a silastic patch over the diaphragmatic defect (immediate reduction). The fourth group were normal controls. All surviving lambs (n = 8 in each group) were delivered by Cesarian section at 141-143 days (term = 145-149 days). Lungs were obtained at autopsy, inflation-fixed, divided into lobes, and sampled, and morphometric analysis was performed. Comparisons were made between these groups and with matched normal controls and CDH untreated animals prepared in conjunction and previously reported. The lungs from the CDH animals treated by both methods of fetal hernia repair showed significant lung growth and structural development and maturation, although they remained significantly hypoplastic compared to normal. There were minor differences in the lung parameters between these two groups, with a tendency for the slow method to provide more normal parameter values. An exception was the increase in lung volume that was greater for the immediate (patch) method, particularly in the left lower lobe. In conclusion, intrauterine hernia repair by both methods is capable of partially reversing total lung and lobar structural hypoplasia and immaturity. The slow reduction method, with reduced potential for mortality and morbidity, is at least as good at reversing pulmonary hypoplasia as the immediate method. Alternative intrauterine interventions to prevent or reverse pulmonary hypoplasia are discussed and compared with the hernia repair methods used in this study.

Animals↗
PubMed2000

A comparison of standard gamble, time trade-off, and adjusted time trade-off scores.

OBJECTIVE: To adjust patients' time trade-off (TTO) scores using information on their utility functions for survival time to derive a measure of health state utility equivalent to the standard gamble (SG). METHODS: A sample of 199 cardiovascular patients were asked three TTO and SG questions (to assess their own health state), and three certainty equivalent questions (to assess their utility function for survival time) in an interview. RESULTS: Patient's utility functions for time were increasingly concave, but being unable to model this successfully, a constant function with an averaged level of concavity was used. The raw TTO scores were significantly higher than SG scores, while the adjusted TTO scores were equivalent to the SG. CONCLUSIONS: Raw time trade-off scores will give biased estimates of health state utility when patients' utility functions for time are not linear, but these can be adjusted to yield true utilities. The constant proportional risk-posture assumption of the conventional QALY model, on which previous attempts to adjust time trade-offs have been based, was not supported by the data.

Cardiovascular Diseases↗
PubMed2000

The relationship between asthma severity, family functioning and the health-related quality of life of children with asthma.

This study compared the health-related quality of life (HRQL) of 236 children with mild or moderate/severe asthma with that of a large representative sample of children in the general community. The study also examined the relationship between the HRQL of children with asthma and their demographic characteristics, asthma severity and family functioning. Children with asthma had a significantly poorer HRQL than other children in the community. Amongst the children with asthma, parents reported that children living in single-parent families had poorer physical health, mental health and social functioning than children in two-parent families. There was a significant relationship between the mental health of children with asthma and family functioning but no significant relationship between their physical health and family functioning. These findings suggest that the domains comprising the HRQL of children with asthma are related to both disease and non-disease factors. A better understanding of these relationships will facilitate the development of new interventions to help children with asthma.

Asthma↗
PubMed2000

Airway gene transfer in mouse nasal-airways: importance of identification of epithelial type for assessment of gene transfer.

Mouse nasal airways are often used for the assessment of both reporter and cystic fibrosis transmembrane conductance regulator (CFTR) gene transfer to respiratory epithelia. However, the mouse nasal cavity is lined by both olfactory (OE) and respiratory epithelium (RE). Previous gene transfer studies have suggested that OE may be more efficiently transduced by adenoviral vectors than RE. However, to provide data pertinent to CFTR gene transfer in humans, measurements of CFTR function in mice by transepithelial potential difference (TPD) should be directed towards respiratory rather than olfactory epithelium. We report a new technique to mark the position of the TPD sensing cannula tip in the mouse nasal cavity that permitted us to correlate TPD measurements with epithelial cell type. Using this technique, we found TPD values did not discriminate between respiratory and olfactory epithelia. We next assessed relationships between anatomic regions accessed by the TPD cannula and epithelial type. The frequently used insertion depth of approximately 5 mm from the nose tip predominantly recorded the TPD from anterior dorsal olfactory epithelium. Measurement of the TPD of respiratory epithelium in our study was maximized by insertion of the TPD cannula probe to 2.5 mm depth. Because TPD measurements are not sensitive to epithelial type, adequate control of position and TPD catheter insertion depth are required to ensure accurate estimation of CFTR gene transfer into the target RE in the mouse nasal cavity.

Animals↗
PubMed2000

Intraoperative magnetic resonance imaging.

Intraoperative magnetic resonance imaging (MRI) allows neurosurgeons to perform surgery interactively using magnetic resonance (MR) guidance. Low-field and high-field strength MRI has been developed and implemented for multiple neurosurgical procedures, including brain biopsies, craniotomies for resection of mass lesions, cyst drainages, laminectomies, thermal ablations, functional neurosurgery, and a variety of miscellaneous cases. Both technologies have the advantage over frameless neuronavigational systems of being able to perform near real-time imaging, which allows the surgeon to compensate for intraoperative brain shift. Intraoperative functional techniques such as MR spectroscopy, functional MRI, MR angiography and venography, and diffusion-weighted imaging, which have become routine at some high-field MR units, can significantly influence surgical decision making. The potential complications associated with intraoperative MR-guided neurosurgery are similar in incidence to those seen in the conventional neurosurgical operating room. However, the immediate recognition of such intraoperative complications with MRI should lead to improved outcomes and decreased medical costs. Untoward events associated with performing surgery in an MR environment are uncommon. Intraoperative MR-guided neurosurgery represents a natural progression from framed and frameless stereotactic techniques. Intraoperative MRI is still in its infancy, and the full capabilities of this technology have yet to be determined or implemented.

Humans↗
PubMed2000

Safety, efficacy, and functionality of high-field strength interventional magnetic resonance imaging for neurosurgery.

OBJECTIVE: Interventional magnetic resonance imaging (MRI) allows neurosurgeons to interactively perform surgery using MRI guidance. High-field strength (1.5-T) imaging permits exceptional observation of intracranial and spinal pathological features. The development of this technology and its application to a variety of neurosurgical procedures are described. METHODS: We report on the first 101 cases that were treated in the interventional MRI unit (between January 1997 and September 1998). These cases included 39 brain biopsies, 30 tumor resections, 9 functional neurosurgical cases, 8 cyst drainages, 5 laminectomies, and 10 miscellaneous cases. Patients ranged in age from 14 months to 84 years (median, 43 yr); 61 patients were male and 40 were female. Intraoperative functional techniques that were used to influence surgical decision-making included magnetic resonance spectroscopy, functional MRI, magnetic resonance angiography and venography, chemical shift imaging, and diffusion-weighted imaging. All surgery was performed using MRI-compatible instruments within the 5-gauss line and conventional instruments outside that line. RESULTS: All 39 brain biopsies yielded diagnostic tissue. Of the 30 tumor resections, 24 (80%) were considered radiographically complete. The incidence of serious complications was low and was comparable to that associated with conventional operating rooms. One patient developed a Propionibacterium acnes brain abscess 6 weeks after surgery and another patient experienced Staphylococcus aureus scalp cellulitis after a brain biopsy, yielding an infection rate of less than 2%. No clinically significant hemorrhage was observed in immediate postoperative imaging scans, although one patient developed a delayed hematoma after a thalamotomy. One patient experienced a stroke after resection of a hippocampal tumor. No untoward events were associated with MRI-compatible instrumentation or intraoperative patient monitoring. CONCLUSION: High-field (1.5-T) interventional MRI is a safe and effective technology for assisting neurosurgeons in achieving the goals of surgery. Preliminary results suggest that the functional capabilities of this technology can yield data that can significantly influence intraoperative neurosurgical decision-making. The rates of serious complications, such as infection, associated with this new technology were low.

Adolescent↗
PubMed2000

Late presentation of upper airway obstruction in Pierre Robin sequence.

A retrospective review was carried out of 11 consecutive patients with the Pierre Robin sequence referred to a tertiary paediatric referral centre over a five year period from 1993 to 1998. Ten patients were diagnosed with significant upper airway obstruction; seven of these presented late at between 24 and 51 days of age. Failure to thrive occurred in six of these seven infants at the time of presentation, and was a strong indicator of the severity of upper airway obstruction. Growth normalised on treatment of the upper airway obstruction with nasopharyngeal tube placement. All children had been reviewed by either an experienced general paediatrician or a neonatologist in the first week of life, suggesting that clinical signs alone are insufficient to alert the physician to the degree of upper airway obstruction or that obstruction developed gradually after discharge home. The use of polysomnography greatly improved the diagnostic accuracy in assessing the severity of upper airway obstruction and monitoring the response to treatment. This report highlights the prevalence of late presentation of upper airway obstruction in the Pierre Robin sequence and emphasises the need for close prospective respiratory monitoring in this condition. Objective measures such as polysomnography should be used, as clinical signs alone may be an inadequate guide to the degree of upper airway obstruction.

Age of Onset↗
PubMed2000

Brain tumor resection: intraoperative monitoring with high-field-strength MR imaging-initial results.

PURPOSE: To investigate the challenges and benefits of magnetic resonance (MR) imaging during brain tumor resection. MATERIALS AND METHODS: A short-bore 1.5-T MR system equipped with echo-planar-capable gradients was used in resection of brain tumors in 30 patients. MR sequences and need for contrast material enhancement were determined on the basis of the targeted lesion. MR images were acquired before, during, and after surgery. Tissue obtained at biopsy or excised as a result of intraoperative MR findings was examined histopathologically. RESULTS: MR images of enhancing lesions proved to be the most challenging to interpret intraoperatively, and relative enhancement at the resection cavity boundary was not specific for residual tumor. The ability to detect residual tumor intraoperatively resulted in a radiologically complete resection in 24 (80%) of 30 patients. The frequency of complications was low, and no untoward effects related to the MR environment were observed. CONCLUSION: Intraoperative MR imaging provided valuable information on the completeness of resection, and resection progress was well demonstrated during surgery.

Adolescent↗