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Biomedical subjects

J A Wilson

Publications and source records attributed to J A Wilson.

At least 91 records · Page 5Linked to original sources
PubMed2000

Harmonic hepatic US with microbubble contrast agent: initial experience showing improved characterization of hemangioma, hepatocellular carcinoma, and metastasis.

PURPOSE: To characterize blood flow in focal hepatic lesions with harmonic ultrasonographic (US) imaging and a microbubble contrast agent. MATERIALS AND METHODS: Thirty patients with known hepatic masses were examined after injection of a perfluorocarbon microbubble agent. Tumor vascularity was assessed with continuous, harmonic gray-scale imaging with a low mechanical index (MI). Tumor vascular volume was assessed with brief, high-MI insonation called interval-delay imaging, which caused microbubble destruction. As the total contrast agent volume in the liver reflects the total vascular volume, quantitation of lesion enhancement relative to normal hepatic enhancement helped determine the vascular volume of the tumor relative to that of normal parenchyma. RESULTS: Low-MI continuous harmonic imaging showed lesional vessels in hepatocellular carcinomas, minimal or no vessels in hemangiomas, and variable vascularization in metastases. High-MI interval-delay imaging showed greater enhancement in hepatocellular carcinomas than in normal liver (P <.02) and showed less enhancement in hemangiomas than in normal liver (P <.02). Enhancement in metastases was greater in the margins than in the center; as a result, the lesions appeared smaller (P <.03) and less well defined on the interval-delay images. CONCLUSION: Contrast-enhanced harmonic imaging appears superior to conventional Doppler US for hepatic mass characterization. Low-MI continuous and high-MI interval-delay imaging can help assess tumor vascular pattern and microvascular volume.

Adult↗
PubMed2000

Angiotensin-converting enzyme expression in human carotid artery atherosclerosis.

Angiotensin-converting enzyme (ACE) inhibitors reduce the progression of atherosclerosis in animal models and reinfarction rates after myocardial infarction in humans. Although expression of components of the renin-angiotensin system has been reported in human coronary arteries, no data regarding their presence in carotid arteries, a frequent site for the occurrence of atherosclerosis plaques, are available. The following study sought to determine whether ACE mRNA and protein can be detected in human carotid atheromatous lesions. Twenty-four intact endarterectomy specimens were obtained from patients with severe carotid occlusive disease (17 males and 7 females, aged 68+/-1 years) and fixed within 30 minutes. Carotid artery specimens contained advanced Stary type V and VI lesions, and human ACE mRNA expression and protein were localized in cross sections by the combination of in situ hybridization and immunohistochemistry. Cell type-specific antibodies were used to colocalize ACE to smooth muscle cells, endothelial cells, macrophages, or lymphocytes. ACE protein was localized in the intima, whereas the overlying media was largely free of ACE staining. In less complicated lesions, ACE staining was modest and could be visualized in scattered clusters of macrophages and on the luminal side of carotid artery vascular endothelium. Smooth muscle cells were largely negative. ACE staining increased as lesions became more complex and was most prominent in macrophage-rich regions. The shoulder regions of plaques contained numerous ACE-positive macrophage foam cells and lymphocytes. In these areas, microvessels were positive for endothelial cell and smooth muscle cell ACE expression. However, microvessels in plaques free of inflammatory cells were stained only faintly for ACE expression. Labeling for ACE mRNA mirrored the pattern of protein expression, localizing ACE mRNA to macrophages and microvessels within the intima. In conclusion, atherosclerosis alters carotid artery ACE production, increasing transcription and translation within regions of plaque inflammation. These data provide another important mechanism by which inflammation associated with increased ACE expression may contribute to the progression of atherosclerosis.

Aged↗
PubMed2000

Extracranial neurilemmoma: a case report and review of the literature.

A 14-year-old male presented with a several month history of an asymptomatic right cervical swelling. An ultrasound scan showed a solid lesion superficial and superior to the thyroid gland. Surgical excision of the lesion was carried out and histological examination revealed a neurilemmoma. Neurilemmomas are relatively rare tumours and even rarer in children. The incidence of such tumours and the management of our patient are discussed.

Adolescent↗
PubMed1999

Review of 31 cases of anterior thoracolumbar fixation with the anterior thoracolumbar locking plate system.

Anterior fixation devices for the thoracolumbar spine have gained wide acceptance as viable alternatives to long-segment posterior fixation in cases of thoracolumbar spine trauma. This review was undertaken to evaluate the safety and efficacy of the Synthes anterior thoracolumbar locking plate (ATLP) system. Over a 3-year period, 31 patients with unstable traumatic fractures of the thoracolumbar spine underwent corpectomy, placement of a structural bone graft, and anterior fixation in which the Synthes ATLP system was used. Long-term follow-up data were obtained in 29 patients. Two patients were lost to follow up, one at 4 months and the other at 1 year. In the remaining patients, the average length of follow up was 20 months. In all patients radiographic evidence of solid bone fusion was demonstrated on follow-up plain x-ray films, and there were no signs or symptoms of pseudarthrosis. No patient suffered neurological deterioration as a result of surgery, and there was relatively little morbidity associated with this plating system. To date, none of the patients in this study has developed any delayed complications related to the fixation device. In one patient, who had sustained a severe flexion injury, loosening of the anterior fixation device occurred, and the patient developed progressive kyphosis, which required a posterior stabilization procedure. These results appear slightly better than those obtained in published studies in which other anterior plating systems were used, indicating that this system is safe and effective in the treatment of unstable fractures of the thoracolumbar spine.

Journal Article↗
PubMed1999

Swallowing abnormalities after acute stroke: A case control study.

Dysphagia is a common and potentially fatal complication of acute stroke. However, the underlying pathophysiology, especially the relative importance of motor and sensory dysfunction, remains controversial. We conducted a case control study of 23 acute stroke patients (mean age = 72 yr) at a median of 6 days post-stroke and 15 healthy controls (mean age = 76 yr). We used novel methods to assess swallowing in detail, including a timed videoendoscopic swallow study and oral sensory threshold testing using electrical stimulation. Vocal cord mobility and voluntary pharyngeal motor activity were impaired in the stroke group compared with the controls (p = 0.01 and 0.03). There was a delay during swallowing in the time to onset of epliglottic tilt in the stroke group, particularly for semisolids (p = 0.02) and solids (p = 0.01), consistent with a delay in initiation of the swallow. Sensory thresholds were not increased in the stroke group compared with controls. We conclude that pharyngeal motor dysfunction and a delay in swallow initiation are common after acute stroke. Vocal cord mobility is reduced, and this may result in reduced airway protection. We found no evidence to support the hypothesis that oropharyngeal sensory dysfunction is common after acute stroke.

Acute Disease↗
PubMed1999

Is an organic/functional distinction psychologically meaningful in patients with dysphonia?

Dysphonia (hoarseness) is a common clinical condition and, if persistent, patients are referred to otolaryngology clinics for clinical examination. During the examination, a clinical distinction is often made among three types of patients: (1) those with a clear organic basis for dysphonia (cancer, vocal cord palsy): (2) those with some degree of organic pathology; and (3) those with an apparently functional etiology. Functional patients are often characterized as having a psychogenic disorder. This study assessed the psychological validity of the functional category in 204 out-patients (aged 17 to 87 years) with persistent hoarseness of types (2) and (3). Following clinical examination, a consultant otolaryngologist categorized patients as having functional or organic etiology. Subjects were then compared on measures of personality and psychological distress. Dysphonic subjects showed marked psychological distress compared with norms, and reported significantly more previous psychosomatic symptoms than norms, but there were no differences in personality or psychological distress between organic and functional subgroups of dysphonics.

Adolescent↗
PubMed1999

Parapharyngeal lipoma.

Lipomas of the parapharyngeal space provide both a diagnostic and therapeutic challenge. They are extremely rare with only a few cases having been reported. We present the case of a right parapharyngeal space lipoma in a 69-year-old man that was excised via a transcervical approach.

Aged↗
PubMed1999

Primary tuberculosis of the posterior oropharyngeal wall.

We report a case of primary tuberculosis of the posterior oropharyngeal wall presenting with sore throat, fever and malaise. Pharyngeal tuberculosis is rare and usually occurs with primary pulmonary disease. Primary disease has been reported in small numbers in the nasopharynx and palatine tonsil but never before, to our knowledge, in the posterior oropharyngeal wall.

Adult↗
PubMed1999

Immunohistochemical detection of oestrogen and progesterone receptors in salivary tumours.

The purpose of this study was to determine the oestrogen and progesterone receptor status of a selection of salivary tumours. Using immunohistochemistry, we detected nine oestrogen receptor and six progesterone receptor positive tumours from a sample of 36. One acinic cell carcinoma and two mucoepidermoid carcinomas demonstrated positivity for both receptors. We suggest that there may be role for oestrogen manipulation in the management of some salivary tumours.

Female↗
PubMed1999

The efficacy of three common hospital liquid germicides to inactivate Cryptosporidium parvum oocysts.

We evaluated three commonly used hospital disinfectants against three concentrations of Cryptosporidium parvum oocysts (1.5 x 10(6), 1.5 x 10(5), 1.5 x 10(4)). A 10% phenol product, a 10% povidone-iodine product and a 2.5% glutaraldehyde product were tested against Cryptosporidium parvum oocysts without organic load. In-vitro excystation was used to determine viability and a cell culture assay was used to determine infectivity of germicide-treated oocysts. A 2.5% glutaraldehyde product was the most effective in halting excystation of sporozoites and infection in cell monolayers. However, this occurred only at the longest exposure time of 10 h and with the lowest concentration of oocysts (1.5 x 10(4)). The 10% phenol product and the 10% povidone-iodine product also decreased excystation, but were unable to halt infection. Although the ability of C. parvum to with-stand chemical treatment is well known, the ability of oocysts to remain viable and infectious after a 10 h treatment in glutaraldehyde is cause for concern. Endoscopic equipment that may come into contact with these organisms cannot be immersed into glutaraldehyde for this length of time due to its corrosive nature. Thus, the results of this research are cause for concern in hospital disinfection units.

Animals↗
PubMed1999

Perioperative dextromethorphan reduces postoperative pain after hysterectomy.

UNLABELLED: We studied the effect of dextromethorphan, an N-methyl-D-aspartate antagonist, on analgesic consumption and pain scoring after abdominal hysterectomy. In this double-blinded study, 50 patients were randomized into two groups. Group DM was given oral dextromethorphan 40 mg with their premedication, then 40 mg three times per day for the next 2 days. Group P received placebo at identical times. Postoperative analgesic requirements were assessed using a patient-controlled analgesia system and subsequent oral analgesic intake using a set protocol. Pain was assessed at rest and on movement using a visual analog scale 4, 24, 48, and 72 h after the operation. Median pain scores at rest were significantly lower at 48 and 72 h and also for the sum of all resting pain scores. Mean morphine consumption was less in Group DM (1.1 vs 1.5 mg/h; P = 0.054). Usage of oral diclofenac, given every 8 h as needed, did not differ between groups, but consumption of codydramol (paracetamol 500 mg and dihydrocodeine 10 mg) was significantly less in Group DM. We conclude that the use of oral dextromethorphan has an analgesia-sparing effect and some beneficial effects on pain scoring at rest after abdominal hysterectomy. IMPLICATIONS: Patients given dextromethorphan before and after surgery had a significant reduction in some pain scores at rest, but not on movement. There was a trend to lower morphine requirements in the first 24 h. Over the next 48 h, oral analgesic usage was significantly reduced.

Administration, Oral↗
PubMed1999

Positron emission tomography studies confirm the need for early surgical intervention in patients with single-suture craniosynostosis.

Craniosynostosis, the premature fusion of one or more cranial sutures, may occur in isolation or in association with a syndromic constellation. Multiple-suture synostosis has consistently been associated with brain compression and increased intracranial pressure, and frequently decreased cognitive development. Single-suture craniosynostosis, however, has been thought by some to be an aesthetic problem with infrequent consequences on brain function and development. Some studies have disputed this concept and have argued a correlation between single-suture craniosynostosis and abnormalities in development. The purpose of this study was to determine, using an objective radiographic tool, positron emission tomography scans, if patients with single-suture craniosynostosis had any abnormalities in cerebral glucose metabolism that would indicate changes in local brain function. A total of 10 children with single-suture craniosynostosis, eight males and two females, ranging in age from 0.1 to 3.2 years, were enrolled in this prospective study approved by the Internal Review Board. Six of the children had sagittal synostosis, three had metopic synostosis, and one had coronal craniosynostosis. Each of the patients had preoperative positron emission tomography scans performed 1 to 5 weeks before cranial reconstructive surgery and postoperative scans at 6 to 12 weeks after surgery. Surgical treatment consisted of cranial vault remodeling in eight of the children and strip craniectomy with cranial expansion in two of the children. After surgery, the two scans were compared qualitatively and quantitatively by a single radiologist. The results demonstrated variable regional increases and decreases in local post-operative cerebral glucose metabolism. However, in the posterior occipital region, the area of visual development and visual spatial coordination, there was a consistent postoperative increase in all 10 patients. Maximum glucose metabolic rate was increased up to 30.2% with a mean of 9.9%, and average glucose metabolic rates demonstrated a maximum increase of up to 18.8%. The results of this study indicate cerebral glucose metabolism consistently increases in the posterior occipital cortex after surgical release of single-suture craniosynostosis. Future developmental studies are being performed to examine the functional consequences of these metabolic changes.

Age Factors↗
PubMed1999

Morphological assessment of the soft palate in habitual snoring using image analysis.

OBJECTIVES: Define differences in palatal and uvular dimensions between habitual snorers and healthy nonsnoring control subjects. Document the changes in palatal configuration after different types of palatoplasty. STUDY DESIGN: A prospective controlled clinical study was performed analyzing video recordings of the soft palate and oropharynx of 251 subjects (121 habitual snorers, 79 patients after laser-assisted uvulopalatoplasty ([LAUP], and 51 healthy volunteers). METHODS: The recordings were captured using a rigid endoscope with a reference measure applied to the soft palate and a mark at the junction of the soft and hard palate. Four parameters were studied in the captured pictures after correction for the distortion deformity in fiberoptic endoscopic images: 1) length of soft palate, 2) length of uvula, 3) width of uvula, and 4) distance between posterior pillars. RESULTS: Analysis showed that habitual snorers, compared with healthy volunteers have significantly increased soft palate length (P = .00001), increased uvula length (P = .0002) and width (P = .00001), and narrowed oropharyngeal isthmus (distance between the posterior pillars) (P = .04). In patients studied after LAUP, the length of the soft palate is significantly shorter (P = .00001) than in the preoperative cohort, and the oropharyngeal isthmus is significantly narrower (P = .00001). Moreover, this latter distance is significantly narrower (P = .00001) when compared with healthy volunteers. CONCLUSIONS: Habitual snorers have a long soft palate, a long wide uvula, and a narrowed oropharyngeal isthmus. LAUP shortens and tightens the elongated palate and causes a further reduction in the space between the posterior pillars.

Adult↗
PubMed1999

In vivo and in vitro analysis of baculovirus ie-2 mutants.

Upon transient expression in cell culture, the ie-2 gene of Autographa californica nuclear polyhedrosis virus (AcMNPV) displays three functions: trans activation of viral promoters, direct or indirect stimulation of virus origin-specific DNA replication, and arrest of the cell cycle. The ability of IE2 to trans stimulate DNA replication and coupled late gene expression is observed in a cell line derived from Spodoptera frugiperda but not in a cell line derived from Trichoplusia ni. This finding suggested that IE-2 may exert cell line-specific or host-specific effects. To examine the role of ie-2 in the context of infection and its possible influence on the host range, we constructed recombinants of AcMNPV containing deletions of different functional regions within ie-2 and characterized them in cell lines and larvae of S. frugiperda and T. ni. The ie-2 mutant viruses exhibited delays in viral DNA synthesis, late gene expression, budded virus production, and occlusion body formation in SF-21 cells but not in TN-5B1-4 cells. In TN-5B1-4 cells, the ie-2 mutants produced more budded virus and fewer occlusion bodies but the infection proceeded without delay. Examination of the effects of ie-2 and the respective mutants on immediate-early viral promoters in transient expression assays revealed striking differences in the relative levels of expression and differences in responses to ie-2 and its mutant forms in different cell lines. In T. ni and S. frugiperda larvae, the infectivities of the occluded form of ie-2 mutant viruses by the normal oral route of infection was 100- and 1,000-fold lower, respectively, than that of wild-type AcMNPV. The reduction in oral infectivity was traced to the absence of virions within the occlusion bodies. The infectivity of the budded form of ie-2 mutants by hemocoelic injection was similar to that of wild-type virus in both species. Thus, ie-2 mutants are viable but exhibit cell line-specific effects on temporal regulation of the infection process. Due to its effect on virion occlusion, mutants of IE-2 were essentially noninfectious by the normal route of infection in both species tested. However, since budded viruses exhibited normal infectivity upon hemocoelic injection, we conclude that ie-2 does not affect host range per se. The possibility that IE-2 exerts tissue-specific effects has not been ruled out.

Animals↗
PubMed1999

Functional esophageal disorders.

The functional esophageal disorders include globus, rumination syndrome, and symptoms that typify esophageal diseases (chest pain, heartburn, and dysphagia). Factors responsible for symptom production are poorly understood. The criteria for diagnosis rest not only on compatible symptoms but also on exclusion of structural and metabolic disorders that might mimic the functional disorders. Additionally, a functional diagnosis is precluded by the presence of a pathology-based motor disorder or pathological reflux, defined by evidence of reflux esophagitis or abnormal acid exposure time during ambulatory esophageal pH monitoring. Management is largely empirical, although efficacy of psychopharmacological agents and psychological or behavioral approaches has been established for several of the functional esophageal disorders. As gastroesophageal reflux disease overlaps in presentation with most of these disorders and because symptoms are at least partially provoked by acid reflux events in many patients, antireflux therapy also plays an important role both in diagnosis and management. Further understanding of the fundamental mechanisms responsible for symptoms is a priority for future research efforts, as is the consideration of treatment outcome in a broader sense than reduction in esophageal symptoms alone. Likewise, the value of inclusive rather than restrictive diagnostic criteria that encompass other gastrointestinal and non-gastrointestinal symptoms should be examined to improve the accuracy of symptom-based criteria and reduce the dependence on objective testing.

Esophageal Motility Disorders↗
PubMed1999

Rapid thrombectomy of superior sagittal sinus and transverse sinus thrombosis with a rheolytic catheter device.

Thrombosis of the dural venous sinuses is a potentially lethal condition that remains a diagnostic dilemma. Clinical outcome is typically dependent on the timeliness of diagnosis and definitive treatment. We report a case of successful rapid thrombectomy of extensive thrombus within the superior sagittal and transverse sinuses using a rheolytic catheter device. This appears to be a promising treatment option, particularly in those patients who do not respond to other, more established, forms of therapy.

Acute Disease↗
PubMed1999

GI emergencies: rapid therapeutic responses for older patients.

Comorbid conditions and decreased physiologic reserves make persons age 65 and older particularly vulnerable to the adverse consequences of acute blood loss. Thus, gastrointestinal bleeding in this population presents an urgent clinical challenge. Treatment of such emergencies may be the preview of the gastroenterologist, but the primary care physician can play a key role in the preliminary diagnosis and management, timely referral for emergency intervention, and follow-up care. Because of age-related changes, including decreased cardiovascular reserve and a higher risk of hemorrhage, any evidence of GI bleeding in an older patient demands diligent intervention.

Aged↗