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Biomedical subjects

A Jackson

Publications and source records attributed to A Jackson.

At least 253 records · Page 14Linked to original sources
PubMed1994

Comparison of laser Doppler perfusion imaging, laser Doppler flowmetry, and thermographic imaging for assessment of blood flow in human skin.

In this study we compared three non-invasive methods of measuring skin perfusion, thermographic imaging (TI), laser Doppler flowmetry (LDF) and the new technique of laser Doppler imaging (LDI). Seven normal volunteers were studied in a temperature-controlled room with an ambient temperature of 22 +/- 1 degree C. Images of the left hand were recorded using LDI followed by TI. LDF was then used on two standard locations on the fingers and back of the hand. The measurements were then repeated for a hot (37 degrees C) and then a cold (10 degrees C) challenge. A significant linear correlation (r = 0.960, p < 0.01, with 95% confidence limit of 0.35-0.77, n = 38) was found between LDF and LDI. However, LDF and LDI did not correlate well with TI (r = 0.577, p < 0.01, with 95% confidence limit of 0.32-0.76, n = 38). The LDI method was found to be highly reproducible (mean +/- 1 SD; 625 +/- 30, with coefficient of variation 5%). The blood flow and temperature distribution of skin of the hand was then recorded using TI and LDI in 10 patients (mean age +/- SD, 41.7 +/- 9.9) with scleroderma and eight normal volunteers (mean age +/- SD, 30.6 +/- 6.5). The overall mean blood flow and temperature in the hands of patients with scleroderma (mean +/- SD 444 +/- 265 flux, 29.3 +/- 3.3 degrees C) was significantly (p < 0.0001) lower compared with the normal volunteers (mean +/- SD, 912 +/- 390 flux, 34.0 +/- 3.2 degrees).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Ovarian metastasis from thyroid carcinoma 12 years after partial thyroidectomy mimicking struma ovarii: report of a case.

A 29-year-old woman experienced abdominal swelling 12 years after undergoing partial thyroidectomy for follicular carcinoma of the thyroid with vascular invasion and 6 months after a right cerebral tumor that had caused hemiplegia had been excised. Laparotomy disclosed a solid and cystic right ovarian tumor, 17 cm in greatest dimension, and a 12-cm tumor of the right adrenal gland. Microscopic examination showed a malignant tumor of the thyroid follicular type with frequent mitotic figures; other teratomatous elements were absent. Because of the interval since the thyroid cancer, the diagnosis of a malignant struma ovarii was initially considered. The patient rapidly developed widespread metastatic disease and died, supporting the interpretation that the ovarian tumor was a metastasis from the thyroid neoplasm. This case illustrates that when other teratomatous elements are not identified, the diagnosis of malignant struma ovarii should be made only when the possibility of spread from a prior thyroid neoplasm, possibly one treated many years previously, has been excluded.

Adenocarcinoma, Follicular↗
PubMed1994

A comparison of arterial lines and insertion techniques in critically ill patients.

We compared three arterial line insertion techniques and two types of arterial catheters in 69 critically ill patients. Use of the direct-puncture technique (method A) was associated with a significantly higher failure rate (23%) than use of a catheter with a separate guide wire (method B, 'classical' Seldinger technique, p < 0.001) or a catheter with an integral guide wire (method C, 'modified' Seldinger technique, p < 0.02). Operators randomly allocated to using method A took significantly longer to perform the procedure than those using method C (p < 0.01), used significantly more catheters (p < 0.0001) and made significantly more punctures in achieving a successful insertion than those using either methods B (p < 0.001) or C (p < 0.001). Both catheter types B and C (polyurethane) were significantly less likely to block, thus requiring less likely to block, thus requiring re-insertion, than catheter type A (Teflon) (p < 0.02, p < 0.01 respectively). We recommend the use of a 'classical' Seldinger technique (method B) for arterial line insertion in critically ill patients and the use of a polyurethane catheter, in preference to Teflon, to maximise catheter life after insertion.

Adolescent↗
PubMed1994

Pharyngeal pouch: link with reflux and oesophageal dysmotility.

Twenty patients aged 56-92 years who underwent surgical correction of pharyngeal pouches at Queen Alexandra Hospital, Portsmouth were asked to fill in a detailed questionnaire. They were then interviewed and barium swallow studies performed from 3 months to 4 years post-operatively. Nineteen patients in the sample were found to have reflux and 20 had dysmotility. These findings suggest that pharyngeal pouches are not a purely localized inco-ordination of the cricopharyngeal sphincter but are associated with a generalized oesophageal muscle dysfunction.

Aged↗
PubMed1994

Prediction of enophthalmos by computed tomography after 'blow out' orbital fracture.

In 11 patients with blow out fracture of the orbit, measurement of orbital volume using computed tomography (CT) more than 20 days after injury correlated well with enophthalmos measured from the same scans (r = 0.87, p < 0.001, SEE 0.63 mm), with a 1 cm3 increase in orbital volume causing 0.8 mm of enophthalmos. This confirms the cause of enophthalmos after blow out fracture to be increase in orbital volume rather than fat atrophy or fibrosis. In a further 25 patients scanned within 20 days of injury the degree of enophthalmos was less marked than would be predicted from the orbital volume measurement. This was probably because of the presence of oedema, haemorrhage, or both behind the globe which would prevent immediate development of enophthalmos. CT measurement of orbital volume within 20 days of injury may predict the final degree of enophthalmos and identify those patients at risk of late enophthalmos, allowing appropriate early surgical intervention.

Enophthalmos↗
PubMed1994

Aluminium ring pulls: an invisible foreign body.

The aluminium ring pulls associated with the latest designs of drinks cans can be relatively easily detached from their mounting on the top of the can and subsequently aspirated. Their small size predisposes them to lodge as foreign bodies (FBs) in the throat. The similarity of atomic number between soft tissue (7.5) and aluminium (13) makes detection of these FBs difficult on soft tissue radiography. If aspiration is suspected direct visualization and removal may be indicated even if radiography is negative.

Adult↗
PubMed1994

Trisomy 12 mosaicism in a 7 year old girl with dysmorphic features and normal mental development.

We present the case of a mentally normal 7 year old girl with short stature, scoliosis, atrial septal defect, and dysmorphic features including linear pigmented streaks on the forearms and lower legs. Chromosome analysis of cultured fibroblasts showed trisomy 12 in 9% and 13% of cells from two skin biopsies. Two trisomy 12 cells were found in lymphocytes after analysis of 500 metaphases. Her clinical features are compared with those of other liveborn cases of trisomy 12 mosaicism and the problems of prenatal diagnosis of such an abnormality are discussed.

Abnormalities, Multiple↗
PubMed1994

Atraumatic gluteal compartment syndrome.

A case of atraumatic gluteal compartment syndrome complicated by sciatic nerve palsy and acute rhabdomyolysis is presented. A presumed diagnosis of deep venous thrombosis led to a delay in diagnosis. Gluteal compartment syndrome should be considered in the differential diagnosis of the swollen leg.

Adult↗
PubMed1994

Malignant astrocytoma of the cervico-medullary junction masquerading as Guillain-Barré syndrome.

Brainstem gliomas are rare primary brain tumours which most commonly occur in the midbrain and pons. Malignant gliomas and tumours at the cervico-medullary junction are particularly unusual. The diagnosis of tumours at this site is particularly difficult using computed tomographic (CT) scanning owing to artifacts around the base of the skull. Intrinsic tumours of the cervico-medullary junction may lead to a dissociated motor deficit and the onset of symptoms can be rapid. We describe a patient in whom an isolated ascending motor deficit in association with a raised cerebrospinal fluid protein and a normal CT scan led to an erroneous diagnosis of Guillain-Barré syndrome. The patient was treated on the intensive care unit for an 8-week period before further investigation demonstrated a malignant glioma of the cervico-medullary junction. We recommend confirmation of the diagnosis of polyradiculopathy by nerve conduction studies wherever possible.

Adult↗
PubMed1994

Does degenerative disease of the lumbar spine cause arachnoiditis? A magnetic resonance study and review of the literature.

The magnetic resonance appearances in 165 patients with symptoms suggestive of degenerative lumbar spine disease were reviewed. The aim of the study was to evaluate the relationship between abnormalities of nerve root distribution and degenerative disease of the lumbar spine in the absence of other known risk factors for arachnoiditis. Central clumping of nerve roots was present in 16 patients (9.7%) and was associated with spinal stenosis at one of the affected levels in all (p < 0.001). Spinal stenosis was present in 44 patients giving an incidence of abnormal nerve root distribution of 36% in this group. Nerve root clumping occurred in association with pure spinal stenosis (10 cases), stenosis secondary to disc prolapse (four cases) and degenerative spondylolisthesis (two cases). Nerve root clumping was confined to one vertebral level in nine cases and extended over two to four levels in seven. In five of the latter spinal stenosis was present at multiple levels. The appearance of nerve root clumping described here may result entirely from mechanical apposition of nerve roots but is indistinguishable from the central pattern of nerve root adhesions which occurs in adhesive lumbar arachnoiditis. No abnormalities of nerve root distribution were seen in association with any indicator of degenerative disk disease in the absence of stenosis. We have been unable to demonstrate the previously reported relationship between lumbar disk degeneration and arachnoiditis and discuss this with a critical review of the literature. Abnormal central clumping of nerve roots as described in arachnoiditis may occur in association with spinal stenosis in the absence of other risk factors although the cause for this appearance remains unexplained. Arachnoiditis-like changes extending over more than one vertebral level are rare (7%) except in the presence of spinal stenosis at multiple levels (29%). Awareness of this appearance may avoid a possibly incorrect diagnosis of arachnoiditis in the presence of a treatable stenosis.

Adult↗
PubMed1994

Cross-validation of height and gender estimations of femoral condyle width in osteochondral allografts.

A cross-validation study was conducted on the estimation of femoral condyle width from height and gender. An equation was published in 1989 for estimation of femoral condyle width using in vivo measurements of femoral condyle width from radiographs. Further cross-validation evidence for this equation is reported using in vitro measurements from 27 cadavers. The data indicated a high correlation (r = 0.85) between actual and estimated femoral condyle width and an acceptable standard error of estimate (range, 4.48-4.29 mm). It was concluded that the published equation which uses height and gender to form an estimate of femoral condyle width has acceptable validity and is a useful tool in the selection process of donors for osteochondral allografts.

Bone Transplantation↗
PubMed1994

Localization biopsy for impalpable breast lesions in a district general hospital.

127 patients undergoing localization biopsy for impalpable breast lesions were analysed retrospectively. Patients were included from both the UK Breast Screening Programme and from the symptomatic Breast Clinic. 49.6% of the biopsies were histologically benign, whereas 50.4% were malignant, including in-situ carcinoma. This is a significantly higher cancer rate than previous series. Localization biopsy has an important role in the diagnosis of mammographically suspicious lesions which are impalpable. 80% of the patients originated from the Breast Screening Programme which has important financial implications on surgical workload.

Adult↗
PubMed1993

Pretreatment with gonadotrophin releasing hormone (GnRH) analogue prior to in vitro fertilisation for patients with endometriosis.

To assess the effect of GnRH pretreatment prior to IVF-ET on fertilisation and pregnancy rates in patients with endometriosis compared with tubal infertility, a retrospective analysis of 228 cycles of tubal infertility cases (Group 1) and 92 cycles of endometriosis has been performed. Patients with endometriosis were classified by the revised AFS scoring system to two groups: 37 cycles of minimal and mild endometriosis (Group 2) and 55 cycles of moderate and severe endometriosis (Group 3). The GnRH analogue buserelin was used for pituitary desensitisation in all IVF cycles. Endometriosis patients have a minimum of 6 weeks GnRH treatment prior to superovulation therapy. Although the fertilisation rate per oocyte (51%) was significantly lower in Group 3 (P < 0.001), the percentage of cycles in which fertilisation occurred (86%, 78%, 78%) and the pregnancy rates per embryo transfer (17.7%, 17.2%, 18.6%) for Groups 1, 2 and 3, respectively, were not significantly different. Pretreatment with GnRH analogues allows patients with endometriosis to achieve similar success rates to patients with tubal infertility alone.

Adult↗
PubMed1993

A mouse model for varicella-zoster virus latency.

Following primary infection with varicella-zoster virus (VZV), the virus establishes a latent infection in humans. The molecular pathogenesis of VZV latency is not well understood, mainly due to the lack of an adequate animal model. We report here that we have developed a mouse model for VZV infection that involves corneal inoculation of mice. Although infected animals showed no signs of disease, most of the animals could not eliminate the virus early after infection. By PCR, we demonstrated that at 33 days post-infection (p.i.), viral DNA was still present in more than 60% of the animals (14/21). VZV DNA was most frequently detected in the trigeminal ganglia (7/14) followed by the brain stem (10/21), kidneys (4/21), spleen (3/20), liver (2/21) and brain (1/21). By in situ hybridization, a few cells positive for VZV mRNA were detected in the trigeminal ganglia, brain stem, cerebellum and spleen of a small number of the infected animals as late as 33 days p.i. No viral proteins were detected at the site of inoculation or in any other tissue by immunostaining. Our results suggest that VZV spreads in mice by both viraemia and axonal transport and establishes a non-productive (latent) infection.

Animals↗
PubMed1993

Efficiency and specificity of gene isolation by exon amplification.

Exon amplification is an increasingly popular approach to the identification of transcribed sequences and will complement other strategies to isolate genes. We have used this system to amplify candidate exons from 32 cosmids, including 8 cosmids which span a well characterized 185-kb region of the human major histocompatibility class II region on Chromosome (Chr) 6. We have examined the efficiency, specificity, and reproducibility of the system in isolating exons from genes known to be present on particular cosmids and have determined the nature and frequency of artefact amplifications in routine cosmid screening. We were able to clone at least one exon from 88% (7/8) of all known genes tested (including exons which are differentially spliced) and obtained artefacts from 19% (6/32) of the cosmids tested. Such artefacts generally arise from the amplification of noncoding sequences flanked by regions with high homology to acceptor and donor splice junctions. We show that the exon amplification procedure can be used successfully with a wide variety of cosmids which have different numbers of genes and gene structures and describe several approaches to the characterization of novel exons cloned in this study.

Amino Acid Sequence↗
PubMed1993

The callosal-septal interface lesion in multiple sclerosis: effect of sequence and imaging plane.

We examined the effect of imaging plane and sequence on the demonstration of lesions at the callosal-septal interface (CSI) by magnetic resonance imaging in 20 patients with known multiple sclerosis. Variable-echo-(VE) T2- and proton density (PD) weighted images were performed in coronal axial and sagittal planes. Sagittal gradient echo (GE) T2- and PD-weighted images were also performed. Lesions at the CSI were seen in all patients and were all demonstrated on both sagittal and coronal VE images. Sagittal PD-weighted GE images were slightly less sensitive but showed good overall agreement with sagittal VE. Axial VE and sagittal T2-weighted GE images demonstrated CSI lesions poorly.

Adult↗
PubMed1993

CT appearances of haematomas in the corpus callosum in patients with subarachnoid haemorrhage.

Corpus callosum haematoma is a rare feature in subarachnoid haemorrhage (SAH), which may result from aneurysms of the anterior communicating artery (ACoA) or pericallosal artery (PCA). In 348 patients with aneurysmal SAH, bleeding from ACoA aneurysms in 88 cases produced no abnormality on CT in 7. Blood in the cistern of the lamina terminalis was the most frequent abnormality (76/88); haematomas of the septum pellucidum, confined to patients with ACoA aneurysms, were seen in 26 (30%). Rupture of PCA aneurysms in 12 patients gave rise to blood in the pericallosal cistern, anterior interhemispheric fissure and cistern of the lamina terminalis in 11. There was no blood in the septum pellucidum or the ventricular system in any case, but haematomas in the corpus callosum occurred in 8 (67%). In all of these, blood extended into the anterodorsal aspect of the callosum and spread posteriorly along its dorsal border. An identical, supracallosal pattern was seen in 2 patients (2.5%) with ACoA aneurysms, in whom haemorrhage was more extensive, with a large frontal lobe haematoma extending up from the cistern of the lamina terminalis in 1 and a haematoma of the septum pellucidum, with intraventricular extension in the other. In 8 patients (9%) with ACoA aneurysms a corpus callosum haematoma appeared to result from passage of blood up through the cistern of the lamina terminalis into the septum pellucidum and thence into the ventral aspect of the anterior corpus callosum; blood was present within the cistern, the septum and the ventricles.

Aneurysm, Ruptured↗