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Biomedical subjects

M W Wilson

Publications and source records attributed to M W Wilson.

At least 73 records · Page 4Linked to original sources
PubMed1988

Silent infarction of the brain. Incidental finding demonstrated by SPECT.

Bone imaging of the body is often requested to rule out metastatic disease. A patient with suspected breast carcinoma underwent bone imaging which revealed a focal area of uptake that appeared to be localized in the right posterior calvarium. The initial interpretation was possible solitary metastatic breast carcinoma to the skull. Skull radiographs and head computed tomography (CT) were suggested for follow-up evaluation. The skull series was performed immediately after bone imaging and was negative. Further clinical information revealed that the patient recently had undergone total right internal carotid artery ligation for treatment of a large, surgically inaccessible right cavernous aneurysm. SPECT imaging of the head localized the region of abnormal uptake adjacent to the calvarium, which suggested the uptake was due to a recent brain infarction or metastatic disease to the brain. A CT scan performed 4 days later demonstrated generalized cerebral atrophy, but was otherwise normal, ruling out metastatic breast carcinoma. This case emphasizes the importance of SPECT imaging when a solitary skull lesion is found on bone imaging. SPECT can localize the lesion to be within the brain and/or skull and can aid in further investigative management. A lesion located at the periphery of the brain may be due to an occult stroke. This finding is of particular consideration in the elderly in whom there is a relatively high incidence of coexisting cancer and silent brain infarction.

Aged↗
PubMed1986

A comparison of serotyping, BRENDA-typing and incompatibility grouping, and toxin testing of haemolytic Escherichia coli isolated from piglets before and after weaning.

Before weaning, some young pigs in a research piggery excreted in their faeces a weakly haemolytic non-enterotoxigenic serotype of Escherichia Coli. After weaning, all of the pigs excreted strongly haemolytic Escherichia coli of known enteropathogenic serotypes (0-138 and 0-139). The 0-138 serotype produced vero cell toxin, whilst the 0-139 serotype elaborated heat labile enterotoxin. Haemolytic enterotoxigenic E. Coli were also recovered from three-week-old unweaned piglets with so-called ;milk scours; and from pigs with post-weaning diarrhoea on two local commercial piggeries. Selected haemolytic isolates were compared using serotyping, bacterial restriction endonuclease DNA analysis (BRENDA) and incompatibility grouping. The three typing methods divided most of the isolates into the same groupings; the exceptions were two isolates with the same BRENDA pattern and incompatibility group, but with different H-serotypes, and eleven isolates with the same serotype and BRENDA pattern but which showed differences in colony compatibility such that they were divided into five subgroups of a single incompatibility type.

Journal Article↗
PubMed1981

Pharmacological evidence for multiple sites of action of pressure in mice.

The ability of eight diverse pharmacological agents to ameliorate the high pressure nervous syndrome (HPNS) in mice was studied. Data were obtained for the end points: coarse tremors, complete spasms, clonic convulsions, tonic convulsions, and death. The three anesthetics examined (nitrogen, urethane, and phenobarbital) gave good protection against all end points but especially against tonic convulsions. Furthermore, marked increases (greater than 90 atm) were recorded in the lethal pressure in spite of a fixed linear compression. Some detailed differences among the anesthetics were also noted. Of the anticonvulsants, phenytoin protected against tonic convulsions but actually exacerbated some other end points. Diazepam gave some protection against all phases except the tremors, as did trimethadione. Tetrahydrocannabinol and chlorpromazine had little effect. The pharmacological profiles of these end points are all different, suggesting they represent the effects of pressure at separate and distinct sites in the central nervous system. The HPNS cannot be regarded as a single syndrome.

Animals↗
PubMed1980

Studies on the enterotoxigenicity of environmental Escherichia coli, belonging to serotypes normally considered enterotoxigenic.

Fifteen strains of Escherichia coli which had been collected in previous studies from animals and meat were studied. They belonged to serotypes considered enterotoxigenic and were examined for the production of the heat-labile and heat-stable enterotoxins. Only one of these strains (O8.Hnt) isolated from a cowpat in Cheshire produced heat-labile enterotoxin. Another strain (O8.H9) isolated from a cowpat in another part of Cheshire gave results suggesting production of small amounts of the heat-stable enterotoxin. The ecological aspects of these results are discussed.

Animals↗
PubMed1980

Investigation into an outbreak of food poisoning.

During an outbreak of food poisoning at a church camp, 16 of the 25 people attending were affected. Despite a thorough search for a bacterial pathogen none was identified. An examination of the Escherichia coli serotypes present suggest that E. coli O159. H9 may have been the organism causing the outbreak.

Bacteria↗
PubMed1978

The pressure reversal of a variety of anesthetic agents in mice.

The aim of this work was to study in mammals the ability of high pressures to reverse the anesthesia produced by a wide range of general anesthetics. Dose-response curves were obtained using mice at pressures ranging from 1 to 125 atm for five agents, namely alpha-chloralose, ethylcarbamate, phenobarbital and, for comparison, nitrogen and argon. The increase of ED50 was found to be a linear function of pressure in each case, but the proportionate increases in ED50 with pressure were greater for the three non-inhalation agents than for the two gases. Thus, the ratio of ED50 at 100 atm to that at 1 atm was 1.74 for alpha-chloralose, 1.68 for ethylcarbamate, and 1.54 for phenobarbital. On the other hand, the corresponding ratios for argon and nitrogen were only 1.36 and 1.34. The potencies of three short-acting agents (trichloroethanol, ketamine, and alphadione) were shown to increase with decreasing pressure, although ED50 values could not be obtained. It is concluded that pressure reverses the actions of a wide variety of anesthetics in mice. The results of this study are not inconsistent with either the fluidized lipid membrane or the critical volume hypotheses of anesthetic action.

Alfaxalone Alfadolone Mixture↗
PubMed1970

Effect of glucose and low oxygen tension on L-asparaginase production by a strain of Escherichia coli B.

Cultural and nutritional requirements for maximum l-asparaginase synthesis were determined. Conventional aerobic and anaerobic fermentations were not satisfactory. The former yielded larger quantities of cells containing minimal amounts of l-asparaginase, whereas the latter supplied only minute amounts of bacteria that contained an abundance of enzyme. However, the combination of these classical methods, i.e., allowing growth to proceed aerobically until the mid to late exponential phase and then forcing the facultative microbial cells toward anaerobic metabolism by static incubation, produced 2.6 international units of enzyme per ml of fermentation broth when glucose was present. Enzyme synthesis was not induced by terminating aeration-agitation in the absence of glucose, nor was it induced in the presence of glucose when aeration was continued. Use of 0.2 m phosphate buffer resulted in a constant pH near the optimum value of 7.5 during l-asparaginase formation. Addition of 0.05% l-asparagine prior to induction was also beneficial, but other amino acids or their catabolites failed to increase biosynthesis of l-asparaginase.

Amino Acids↗
PubMedDate not supplied

Incidence of important hemobilia following transhepatic biliary drainage: left-sided versus right-sided approaches.

Our purpose here is to describe our experience with important hemobilia following PTBD and to determine whether left-sided percutaneous transhepatic biliary drainage (PTBD) is associated with an increased incidence of important hemobilia compared to right-sided drainages. We reviewed 346 transhepatic biliary drainages over a four-year period and identified eight patients (2.3%) with important hemobilia requiring transcatheter embolization. The charts and radiographic files of these patients were reviewed. The side of the PTBD (left versus right), and the order of the biliary ductal branch entered (first, second, or third) were recorded. Of the 346 PTBDs, 269 were right-sided and 77 were left-sided. Of the eight cases of important hemobilia requiring transcatheter embolization, four followed right-sided and four followed left-sided PTBD, corresponding to a bleeding incidence of 1.5% (4/269) for right PTBD and 5.2% (4/77) for left PTBD. The higher incidence of hemobilia associated with left-sided PTBD approached, but did not reach the threshold of statistical significance (p = 0.077). In six of the eight patients requiring transcatheter embolization, first or second order biliary branches were accessed by catheter for PTBD. All patients with left-sided bleeding had first or proximal second order branches accessed by biliary drainage catheters. In conclusion, a higher incidence of hemobilia followed left-versus right-sided PTBD in this study, but the increased incidence did not reach statistical significance.

Adult↗
PubMedDate not supplied

Talc pleurodesis through small-bore percutaneous tubes.

Pleurodesis using talc as the sclerosing agent is an effective procedure for preventing reaccumulation of malignant pleural effusions. Because of its thickness, the talc slurry is usually instilled through large bore (20-28 Fr), surgically placed thorocostomy tubes. However, these tubes often cause considerable patient discomfort. Herein we report a series of eight patients in whom the talc slurry was inserted through 10 and 12 Fr percutaneous chest tubes. Six of the eight patients (75%) had a successful pleurodesis without a reaccumulation of fluid. We conclude that this is an acceptable method for treating patients with malignant pleural effusions.

Adult↗
PubMedDate not supplied

Brain structure localization in positron emission tomography: comparison of magnetic resonance imaging and a stereotactic method.

A method commonly used for localization of brain regions on positron emission tomographic (PET) images is direct visualization and designation of structure on the image itself. This technique, however, is limited to portions of the brain having sufficient differential radionuclide uptake to permit the recognition of structure by observers familiar with brain anatomy. Two other methods commonly used instead of direct visualization are magnetic resonance imaging (MRI) and stereotactic methods of localization. This report compares the accuracy of a MRI method versus a stereotactic method of brain structure localization of PET. The three localization methods were analyzed for sixteen different brain regions in 5 different subjects by two independent observers. The results were converted to PET pixel size (1 pixel = .127 cm) for comparison. MRI localization differed from direct visualization by a mean and standard deviation of approximately 2 +/- 1 pixels in both the X and Y dimensions. Stereotactic localization differed from direct visualization by approximately 2 +/- 1 pixels in the X dimension and by approximately 6 +/- 2 pixels in the Y dimension. This larger variation seen with the stereotactic method may be attributed to the questionable assumption of linearity of structure location with respect to size of the inner table of the calvarium.

Adult↗
PubMedDate not supplied

Validation of a reference method for correlation of anatomic and functional brain images.

We describe a reference device that provides accurate correlations between anatomic and functional brain images. The reference device, which generates fiduciary reference points on sequential scan planes, is positioned adjacent to the orbitomeatal line of the subject, and held in place by a framework anchored to the external auditory meatus. The reference system was tested on 17 subjects undergoing Tc-99m-hexamethylpropyleneamine oxime (Tc-99m-HM-PAO) brain single photon emission computed tomography (SPECT) and cranial computed tomography (CT) scans. The centers of the caudate nuclei, thalami, brain stem, and cerebellar vermis were identified independently on CT and SPECT. The average difference +/- 1 sd between structure locations (x, y, and z) on SPECT and CT were calculated as 1.86 +/- 1.5, 2.16 +/- 1.4, and 1.83 +/- 1.9 mm, respectively. The relevance of the method to clinical applications is illustrated by the localization of a recurrent viable glioma and an epileptogenic focus. This reference system provides an accurate, rapid, and noninvasive patient-specific method for the correlation of brain structure with brain function.

Brain↗
PubMedDate not supplied

Chemotherapy for eye cancer.

Chemotherapy has been used to treat a multitude of eye cancers. We attempted to review the role of chemotherapy in the treatment of ocular, adnexal, and orbital malignancies by conducting an extensive search of the medical literature. Unfortunately, the published reports typically contain few patients with limited follow-up, precluding definitive recommendations. For most eye cancers, multicenter trials will offer the potential to gather the numbers of patients required to determine the clinical utility of chemotherapy.

Antineoplastic Agents↗