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Biomedical subjects

P Evans

Publications and source records attributed to P Evans.

At least 19 recordsLinked to original sources

Re-use of syringes.

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Disposable Equipment

Osteoporosis and chronic back pain: a study with single-photon emission computed tomography bone scintigraphy.

A group of 26 patients aged 47-81 years (average 67) with spinal osteoporosis and back pain for more than 6 months were investigated with planar and SPECT bone scintigraphy and anterior and lateral x-rays of the thoracolumbar spine. Abnormal activity on bone scintigraphy was found in all patients, of whom 22 had multiple lesions. A total of 17 (65%) patients had abnormal activity associated with collapsed vertebral bodies, 5 (19%) had degenerative disk disease, and 21 (81%) had facetal joint disease. Of 112 lesions identified by SPECT, 60 (54%) were localized to the apophyseal joints. Facetal lesions were commoner in those patients with more collapsed vertebrae, and 32 facetal lesions (54%) were associated with collapse of the vertebra immediately above or below. Bone scintigraphy findings suggest that in some individuals with osteoporosis and chronic back pain, collapse of the vertebral body or degenerative disk disease are causes of pain. However, the high frequency of increased apophyseal joint activity suggests that the facet joint may also be an important site of origin of pain in these individuals. Bone scintigraphy may identify a subgroup of osteoporotic patients with chronic back pain who would benefit from treatment to the facet joints.

Aged

The effect of vertebral collapse on spinal bone mineral density measurements in osteoporosis.

Bone mineral density (BMD) of the lumbar spine (L1-L4) was measured using dual-energy x-ray absorptiometry (DXA) in 57 postmenopausal women with spinal osteoporosis aged 50-82 years (average age 64). For each vertebra between L1 and L4, the BMD was compared to age-matched normal population values and a Z score obtained. Twenty three patients had between one and three collapsed vertebrae from L1 to L4. The average Z score for fractured vertebrae was -1.62 but for uncollapsed vertebrae was -2.26 (P less than 0.001). The difference in Z scores obtained for collapsed and uncollapsed vertebrae was greater where only one fracture was present (0.803) compared to two (0.577) or three fractures (0.245). The average increase in density for a fractures vertebra was 0.070 g/cm2. For L1 vertebral fractures alone the average increase in BMD was 0.096 g/cm2, L2 vertebral fractures 0.041 g/cm2, L3 fractures 0.029 g/cm2 and L4 fractures 0.062 g/cm2. It is concluded that as vertebral collapse is not alway detected using DXA and usually causes a rise in BMD, spinal x-rays are necessary to avoid misinterpretation of a falsely elevated BMD in osteoporotic patients, particularly in longitudinal studies or when monitoring therapy, where small changes in BMD are important.

Absorptiometry, Photon

Status incongruence and serum cholesterol in an English general practice.

The relationship between status incongruence and serum cholesterol was examined in a case-control study carried out in an English general practice population. Patients (n = 54) with elevated serum cholesterols (greater than or equal to 7.0 mmol/l) were compared to age and sex matched controls (n = 54). A specific type of status incongruence--lifestyle incongruity--was measured as the degree to which style of life (material consumption and status-enhancing behaviors) exceeded occupational status. Lifestyle incongruity was associated with higher serum cholesterol and an increased odds of being a case. This association was independent of age, sex, the body mass index, family history of cardiovascular disease, alcohol use, and, for women, menopausal status. Implications of these results for research on social inequality and the risk of cardiovascular disease are discussed.

Adult

The peripheral nerve allograft in the primate immunosuppressed with Cyclosporin A: I. Histologic and electrophysiologic assessment.

Nerve regeneration across peripheral nerve allografts and control autografts in primates immunosuppressed with Cyclosporin A was quantitatively evaluated by electrophysiologic and histologic methods. Twelve cynomolgus monkeys received 3-cm autografts and allografts in contralateral ulnar nerves. They were immunosuppressed with Cyclosporin A at 25 mg/kg per day or placebo vehicle. Morphometric analysis of nerve graft and distal nerve segments was assessed at 1 year after engraftment. Quantitative electrophysiologic studies were performed percutaneously at 6 and 12 months, and compound action potentials were measured directly across the nerve grafts at 1 year. Excellent regeneration was seen across autografts and allografts in Cyclosporin A-treated and placebo-treated recipients.

Action Potentials

Kinetics of viral replication in experimental rotavirus infection: effects of high dietary fat.

Epidemiological studies suggest that dietary fat can affect the frequency and severity of diarrhoeal illnesses in childhood. To study the effects of dietary fat on the kinetics of rotavirus antigen, 3-week-old mice of rotavirus-seronegative mothers were fed isocaloric diets with 40% of the total calories as fat [either butter (high saturated fat), olive oil (high monounsaturated fat), or corn oil (high polyunsaturated fat)] with one group on low fat (10% of calories) standard diet as controls. Seven-day-old mice from the first litter were killed and their stomach contents (milk) analyzed for total fatty acids. Seven-day-old mice from the second litter were inoculated with EDIM rotavirus, and some were killed at 48 h and others at 120 h postinoculation. The stool was removed from the distal colon of each mouse and examined for evidence of diarrhoea. The small intestine was removed, the contents washed, and the intestine divided into equal thirds. All stool and tissue samples were made to 10% (wt/vol), homogenised, and tested for rotavirus antigen by ELISA. We found that (a) dietary fat markedly altered the fatty acid profile of milk, (b) high saturated dietary fat (butter) delayed the onset of diarrhoea, reduced the excretion of rotavirus antigen in stool, and reduced mucosal antigen in the lower third of the small intestine at 120 h compared to 48 h postinoculation, (c) high polyunsaturated dietary fat initially increased the frequency of diarrhoea and viral antigen in the middle and lower segment at 120 h, followed by a reduction in rotavirus excretion in stool.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Sequencing and characterization of the 185 kDa cell surface antigen of Streptococcus mutans.

The gene spa P (formerly designated as spa P1) encoding the Mr 185,000 surface antigen I/II of Streptococcus mutans, serotype c (strain NG5) has been sequenced. The deduced amino acid sequence of antigen I/II (1561 residues) includes a putative signal peptide (residues 1-38), as well as a transmembrane region (residues 1537-1556). The N-terminal part of the protein (residues 39-550) is particularly rich in alanine and includes three tandem repeats of a sequence of 82 residues. This region is predicted to be alpha-helical, adopting a coiled-coil formation, and may account for the cell surface hydrophobicity associated with expression of antigen I/II. In contrast the C-terminal region (residues 800-1549) is proline-rich, favouring an extended conformation. Comparison with the sequence determined from Strep. mutans strain MT8148 showed that antigen I/II is highly conserved with the exception of a short central region (residues 750-805). N-terminal sequencing of purified antigens I and II components indicated that antigen I extends from the amino-terminus of the intact Mr 185,000 surface antigen while antigen II extends from residue 996.

Amino Acid Sequence

The inhibition of mouse L-cell 45 S ribosomal RNA processing is a highly uv-resistant property of vesicular stomatitis virus.

In mouse L cells infected with vesicular stomatitis virus (VSV), the synthesis of 45 S rRNA and its conversion to 28 S and 18 S rRNA are inhibited during the course of infection. Evidence is presented that the lack of accumulation of stable rRNA species results not only from the decreased transcription and processing of 45 S rRNA, but also from an increased breakdown of pre-rRNA or stable rRNA during processing. In cells prelabeled with [3H]uridine and then infected, the 28 S and 18 S rRNA species remain unaffected. Studies using uv-irradiated VSV indicate that the viral function involved in rRNA synthesis inhibition is slightly more sensitive to uv irradiation than the function involved in processing inhibition. These results suggest that the VSV functions involved in 45 S rRNA synthesis and processing inhibition may be related, or overlapping, but not identical. In cells infected by VSV mutant T1026R1, total RNA synthesis is inhibited, but the distribution of precursor and stable rRNA species remains nearly normal for up to 5 hr after infection. The function of the mutant virus involved in the inhibition of rRNA processing appears to be defective. In mengovirus-infected L cells, 45 S rRNA synthesis, but not processing, is severely inhibited soon after infection, indicating that a decrease in rRNA transcription is not necessarily accompanied by a decrease in processing.

Animals

Comparison between two methods of hydrostatic weighing without head submersion in morbidly obese females.

This study compared two methods of hydrostatic weighing without head submersion to conventional hydrostatic weighting in morbidly obese females. We concluded that hydrostatic weighing without head submersion is a valid alternative to conventional hydrostatic weighing especially when subjects are apprehensive in the water. The use of anthropometric head measures (HWNS-A) did not significantly improve the accuracy of the body composition assessment; therefore, elimination of these time consuming measurements in favor of the direct correction of head above Db is recommended.

Body Composition

The use of the electrostatic potential at the molecular surface in recognition interactions: dibenzo-p-dioxins and related systems.

An ab initio self-consistent-field molecular orbital approach was used to compute the electrostatic potentials of dibenzo-p-dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), two analogues of the latter, and two isomeric benzoflavones on a three-dimensional molecular surface corresponding to the contour of constant electronic density equal to 0.002 electrons/bohr3. The results are discussed in relation to the biological activities of the respective molecules. It is shown that the electrostatic potential graphically depicted on the molecular surface is well suited for the study of recognition interactions, such as are believed to be involved in the initial receptor-mediated step leading to toxicity in the dibenzo-p-dioxins. The surface potential has the advantage of clearly showing steric features that may play a role in understanding the recognition process being investigated.

Computer Graphics

Sequence analysis of the cloned streptococcal cell surface antigen I/II.

The gene spa P (formerly designated as spa P1) encoding the Mr 185,000 surface antigen (I/II) of Streptococcus mutans, serotype c (NG5), has been sequenced. The gene (4683 bp) encodes a protein of 1561 amino acid residues including putative signal peptide (residues 1-38) and transmembrane (residues 1537-1556) sequences. The N-terminal region (60-550) has alanine-rich repeats and is predicted to be alpha-helical. However, the C-terminal region (800-1540) is proline-rich and favours an extended structure. Except for a short central variable region the sequences appear to be highly conserved for S. mutans serotype c. N-Terminal sequencing of separated antigen I and antigen II polypeptides suggests that the former represents the N-terminal and the latter the C-terminal portions of the intact antigen.

Amino Acid Sequence

Sigmoidoscopy in the practice.

This article describes the advantages of using the rigid and flexible sigmoidoscopes for diagnosis and management of large bowel disorders in the surgery. The results of our first years flexible sigmoidoscopy are discussed.

Colonic Diseases

Partial hepatectomy augments the liver's antitumor response.

Despite adequate locoregional control, colorectal metastasis to the liver remains a significant cause of death. Resection of hepatic metastasis improves five-year survival 18% to 34%. A study of the impact of 40% partial hepatectomy on cytokine production in the liver was undertaken. Nonparenchymal liver cells (NPCs) were prepared by collagenase perfusion and metrizamide gradient from partially hepatectomized and laparotomized control C57BL/6Ros mice. Nonparenchymal cell from partially hepatectomized mice compared with laparotomized mice showed a twofold to threefold increase in interferon (IFN) activity. Both interferon alpha/beta and supernatants from cultured NPCs of partially hepatectomized mice suppressed the proliferation of liver-derived MCA-38 colon adenocarcinoma cells in vitro. This tumor has been shown to metastasize to the liver of C57BL/6Ros mice. The production of various cytokines by NPCs induced by partial hepatectomy may provide a possible antimetastatic mechanism.

Adenocarcinoma

Massive venous thrombosis of the extremities.

Massive venous thromboses of the extremities, although uncommon, are responsible for many of the long-term sequelae associated with venous disease. The charts of all patients with a diagnosis of iliofemoral venous thrombosis or subclavian vein thrombosis over a 6-year period were reviewed. There were 59 patients with iliofemoral venous thrombosis and 18 patients with subclavian vein thrombosis. Iliofemoral venous thromboses were three times more common, showed the classic leftsided predominance, and were more likely to be idiopathic. Subclavian vein thromboses showed no side or sex predilection and were due to anatomic abnormalities, intravenous lines, or radiation. Iliofemoral venous thrombosis showed poor response to lytic therapy, whereas subclavian vein thromboses were effectively lysed in those patients in whom it could be used. Massive venous thromboses of the extremities, although similar in presentation, have different characteristics depending upon the extremity affected. The cause, frequency, and response to treatment differ, which could ultimately influence outcome and the severity of postphlebitic symptoms.

Arm

Anthelmintic resistance and the control of ovine ostertagiasis: a drug action model for genetic selection.

A site-specific genetic prediction model is presented, which examines the influences of different anthelmintic treatment regimens on selecting for drug resistance within a sheep management system. The model exploits the power of modern microcomputers to integrate factors such as parasite strain, geographic location, management practice and genetic fitness to identify effective control regimens which do not lead to resistant Ostertagia circumcincta strains over a 30-year horizon. The potential use of the model as a farm level management-support tool is discussed.

Animals