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Biomedical subjects

R Wilson

Publications and source records attributed to R Wilson.

At least 379 records · Page 21Linked to original sources
PubMed1994

Native Canadians relocating for renal dialysis. Psychosocial and cultural issues.

OBJECTIVE: To examine the effects of relocation from remote Native communities for dialysis treatment and explore the receptiveness of patients, caregivers, and their communities to establishing a local satellite dialysis unit. Second, to examine the methodological issues inherent in a qualitative, cross-cultural study. DESIGN: Qualitative descriptive survey using semistructured interviews. SETTING: The Moose Factory Zone (MFZ), situated along the west coast of James Bay in northern Ontario, is one of four geographically defined areas of responsibility within Ontario through which the federal government provides health care services to Native Canadians. PARTICIPANTS: Twenty-four Native residents of MFZ selected by volunteer and nominative sampling techniques. Patients with end-stage or prefailure renal disease, informal caregivers and supporters, professional caregivers, and community spokespersons were included in the study population. MAIN OUTCOME MEASURES: Identification of issues important in planning dialysis services for Native patients in remote communities in the MFZ. RESULTS: Informal caregivers and both categories of patients supported in principle a proposed satellite dialysis unit at Moose Factory General Hospital. Their criticisms of the present system necessitating relocation to urban centres included inadequate social support, inconvenience and expense, and family separation. Professional caregivers generally supported establishing a local dialysis unit but had concerns regarding staff training and continuity of care. Community spokespersons also supported the proposed unit but only if quality of care could be ensured. CONCLUSIONS: Relocation for dialysis treatment disrupts social support patterns and creates psychosocial problems. Although the psychosocial advantages of providing dialysis treatment services close to home are readily apparent, other considerations, such as cost, equipment, and expertise, and training of health care personnel, make the provision of tertiary level care more difficult in isolated areas. Additional study is required to determine the impact of methodological issues inherent in qualitative cross-cultural studies such as this.

Adolescent↗
PubMed1994

Functional vision loss.

BACKGROUND: Functional vision loss (FVL) is a condition whereby a patient experiences a visual deficit without an organic or sensory basis. FVL is a diagnosis of exclusion, made only after organic pathology and sensory problems have been ruled out. METHODS: The authors reviewed the literature on FVL, delineated the etiologies and applied their clinical experience to the subject to provide the reader with a clinical appreciation and practical approach to FVL. This includes diagnostic strategies and etiology-based management. RESULTS: There are numerous sociopsychological etiologies of FVL of which the optometrist should be aware. Since FVL is a non-organic condition, the optimal treatment is usually multi-disciplinary, including a range of providers. CONCLUSIONS: The authors present an overview of FVL, classification of etiology, a diagnostic strategy, comanagement recommendations, and case reports.

Adolescent↗
PubMed1994

Cotton wool spots in AIDS: a review.

BACKGROUND: Cotton wool spots (CWS) result from infarctions of the retinal nerve fiber layer and are seen in a variety of clinical conditions. Most patients with human immunodeficiency virus (HIV) disease, the agent that causes the acquired immune deficiency syndrome (AIDS), demonstrate CWS at some point during their illness. CWS are the most prevalent ocular manifestation found in persons with AIDS. METHODS: A review of the literature was conducted and interpreted to merge a variety of scientific data and clinical studies into a discussion of the etiology, pathophysiology, clinical significance and patient management approaches in patients with AIDS who have CWS. RESULTS: Numerous studies demonstrate a relationship between CWS in patients with low CD4+ lymphocyte cell counts (< 50-100/mm3 of blood), the risk for HIV disease progression, and the development of opportunistic diseases. CONCLUSIONS: While the overall clinical significance of CWS in AIDS is still evolving, it appears that CWS in healthy HIV positive patients have relatively little clinical significance. However, present data suggests that CWS in patients with very low CD4+ counts and advanced HIV disease is a negative prognostic sign. Therefore, CWS in profoundly immunosuppressed patients with low CD4+ counts should alert the optometrist to follow the patient closely.

Acquired Immunodeficiency Syndrome↗
PubMed1994

A vicious circle hypothesis operating during infective exacerbations of chronic bronchitis.

Respiratory tract infections are common. This is partly explained by the lung's function as an organ of gas exchange, which means that it is constantly exposed to inhaled matter, including potential pathogens. The bacteria that cause bronchial infections are relatively nonvirulent, and often form part of the normal upper respiratory tract flora. Impaired lung defences are usually required for these bacteria to colonize the respiratory mucosa, but they then produce factors which facilitate their persistence and contiguous spread through the bronchial tree. This stimulates a host inflammatory response, which becomes chronic if it fails to eliminate the infection. Proteinase enzymes and oxidants spilled by neutrophils, cause mucosal damage, which further compromises the host defences. This makes repeated or chronic infection more likely. The chronic inflammation engendered may contribute to progressive deterioration in respiratory function. Antibiotic management should aim to eradicate the infection, so removing the stimulus to further inflammation. An infection free interval allows the mucosal defences to recover. The past medical history of the patient, the severity of the exacerbation, the likely pathogens and their antibiotic sensitivity, antibiotic penetration into the respiratory mucosa and mucus, and the antibiotic side-effect profile are factors which influence choice of antibiotic, the length of the course and the dosage prescribed.

Anti-Bacterial Agents↗
PubMed1994

Intracellular and extracellular antioxidant buffering levels in erythrocytes from pregnancy-induced hypertension.

Both intracellular (lysate thiol, lysate glutathione and lysate superoxide dismutase) and extracellular (plasma thiol, plasma glutathione and membrane thiol) antioxidant buffering levels were measured in red blood cells from patients with pregnancy-induced hypertension (PIH). We found the following. (1) The levels of plasma thiol and plasma glutathione in PIH women with proteinuria were markedly lower than that in the normal pregnancy. (2) The concentrations of lysate glutathione and superoxide dismutase in PIH women with proteinuria were significantly decreased compared with that in the normal pregnancy. (3) With the exception of plasma and lysate glutathione, all the tested antioxidant markers were not significantly different between PIH women without proteinuria and normal pregnancy. (4) There was no statistical correlation between antioxidant buffering level and BP in patients with PIH. We concluded that both extracellular and intracellular antioxidant buffering levels were decreased in patients with PIH, especially in those with proteinuria. The reduction of the antioxidant buffering level could account for several important pathophysiological features of PIH, such as the elevation of intracellular calcium, decreased red blood cell deformability and endothelial damage.

Adult↗
PubMed1994

Review of the risk of HIV infection through corneal transplantation in the United States.

BACKGROUND: Human immunodeficiency virus (HIV), the pathogen that causes acquired immunodeficiency syndrome (AIDS), has been isolated in the corneal epithelium of some HIV-positive patients. This observation raises concern about the risk of HIV transmission through corneal transplantation surgery (penetrating keratoplasty). METHODS: A comprehensive review of the literature of the ocular transmission of HIV, screening of donor corneas, and the potential of HIV transmission through penetrating keratoplasty was conducted and analyzed to review and interpret the relative risk of HIV infection through corneal transplantation. RESULTS: No cases of HIV transmission were found as a result of routine eye care or ophthalmic surgical procedures, including HIV-serp-negative recipients who inadvertently received HIV-seropositive corneas. CONCLUSIONS: While ocular transmission of HIV appears to be remote, there are still relative risks of HIV transmission due to ophthalmic surgical procedures. Careful screening of donors for HIV infection affords an important increase in the margin of safety for corneal transplantation recipients.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Radiographic detection of occlusal caries: effect of X-ray beam factors on diagnosis.

The aim of this laboratory study was to determine whether the diagnostic potential of bite-wing radiographs in the diagnosis of occlusal caries could be improved by alteration of X-ray beam properties. Bite-wing radiographs of molar teeth with 16 sound and 32 carious occlusal surfaces were taken at conventional settings of 65 kVp, 15 mA and 0.3 s (4.5 mAs) and at 70 kVp, 10 mA and 1.0 s (10 mAs), to produce a darker overexposed film. Results showed that, although the overexposed radiograph resulted in more correct diagnosis of dentine caries, its use increased the number of false-positive diagnoses. More importantly, the experimental exposure factors would have led to an unacceptably high radiation dose to the patient with arguable diagnostic benefit. As such it cannot be recommended in any way for patient examination.

Bicuspid↗
PubMed1993

The interaction of sodium nitroprusside with peripheral white blood cells in vitro: a rationale for cyanide release in vivo.

Isolated monocytes and polymorphonuclear leukocytes release the cyanide anion from the hypotensive agent, sodium nitroprusside. The proposed mechanism involves the production of hydrogen peroxide which oxidizes the substitution inert d6 iron(II) transition metal complex to a labile d5 iron(III) complex. Consequently, the release of cyanide becomes more favoured. This mechanism is supported by the chemical release of the cyanide anion from sodium nitroprusside in vitro by hydrogen peroxide and the demonstrated ability of monocytes and polymorphonuclear leukocytes to generate hydrogen peroxide ex vivo when chemically stimulated by the nitroprusside anion. The results suggest that within a clinical environment white cell counts and cell activation induced as a consequence of disease processes may be important for predicting the toxicity of sodium nitroprusside.

Cells, Cultured↗
PubMed1993

Molecular species composition of glycerophospholipids from white matter of human brain.

The molecular species composition of the major glycerophospholipids from white matter of human brain were determined by high-performance liquid chromatography of the 3,5-dinitrobenzoyl derivatives of the corresponding diradylglycerols. In phosphatidylcholine (PC) and phosphatidylserine (PS), molecular species containing only saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) comprised 85.7 and 82.4% of the respective totals, with 18:0/18:1 predominant in PS and 16:0/18:1 in PC. These molecular species were also abundant in phosphatidylethanolamine (PE), but in this phospholipid species containing polyunsaturated fatty acids (PUFA), largely 18:0/22:6n-3 and 18:0/20:4n-6, accounted for over half the total; 18:1/18:1 was also abundant in PE. In contrast, 1-O-alk-1'-enyl-2-acyl sn-glycero-3-phosphoethanolamine (GPE) had much more SFA- and MUFA-containing species, predominantly 16:0a/18:1, 18:0a/18:1 and 18:1a/18:1, with low amounts of species containing 20:4n-6 and 22:6n-3. In alkenylacyl GPE, 22:4n-6 was the major PUFA and 16:0a/22:4n-6 and 18:1a/22:4n-6 the main PUFA-containing species. There was six times more 22:6n-3, twice as much 20:4n-6 and half the amount of 22:4n-6 in PE as compared to alkenylacyl GPE.

Aged↗
PubMed1993

Production of prostacyclin and thromboxane A2 in mononuclear cells from preeclamptic women.

OBJECTIVE: Although the changes in prostacyclin and thromboxane A2 levels in preeclampsia have been well studied, little work has previously been done on mononuclear cells, and the cause of the changes in unclear. We determined the prostacyclin and thromboxane A2 production in mononuclear cells and investigated the effect of preeclamptic serum on this production. STUDY DESIGN: The production of prostacyclin and thromboxane A2 was measured by enzyme immunoassay in 16 normal pregnant women, nine preeclamptic women with proteinuria, and six preeclamptic women without proteinuria. Sera from these three groups of women were investigated to see whether the sera have any effect on prostaglandin production. RESULTS: The levels of thromboxane A2 in preeclamptic patients were found to be much higher than those of normal pregnancy, whereas the levels of prostacyclin tended to be lower. Such changes lead to a markedly increased ratio of thromboxane A2 to prostacyclin in preeclamptic patients. There was no difference in the levels of prostacyclin and thromboxane A2 between the preeclamptic patients with and without proteinuria. Serum from preeclamptic patients with proteinuria slightly reduced prostacyclin synthesis in normal pregnancy but significantly increased increased thromboxane A2 production, resulting in a ratio of thromboxane A2 to prostacyclin similar to that of preeclampsia. However, serum from preeclamptic patients without proteinuria failed to exert such effects. CONCLUSION: The imbalance between prostacyclin and thromboxane A2 occurs in mononuclear cells from preeclamptic women, and there is a factor(s) in proteinuric-preeclamptic serum to contribute, in part, to these changes. Our findings also suggested that the cause of abnormal prostaglandin production in preeclampsia was complicated and multifactorial.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Prostacyclin, thromboxane and antioxidant levels in pregnancy-induced hypertension.

1. Plasma 6-keto-prostaglandin F1 alpha (6-keto-PGF 1 alpha, a major metabolite of prostacyclin), plasma thromboxane B2 (TXB2, a major metabolite of thromboxane A2) and five antioxidants (indirect markers of reactive oxygen species) namely, plasma thiol, erythrocyte lysate thiol, erythrocyte superoxide dismutase, plasma total glutathione and erythrocyte membrane thiol, were measured in 25 healthy non-pregnant women, 36 normotensive pregnant women and 35 women with pregnancy-induced hypertension (PIH). 2. The levels of TXB2 were significantly increased in normal pregnant women and PIH women with or without proteinuria compared with non-pregnant women. The concentrations of TXB2 in PIH women with proteinuria were higher than those without proteinuria (P < 0.05). 3. The levels of 6-keto-PGF1 alpha in healthy non-pregnant women and PIH women with or without proteinuria were significantly lower than that in normotensive pregnant women (all of three P < 0.01). There were no significant differences between healthy non-pregnant women and PIH women with and without proteinuria. 4. The ratio of TXB2 to 6-keto-PGF1 alpha was markedly elevated in PIH women with or without proteinuria compared with normotensive pregnant women and healthy non-pregnant women. The difference between PIH women with proteinuria and those without proteinuria was not significant (P > 0.05). 5. The levels of plasma thiol, superoxide dismutase and glutathione were significantly decreased in PIH women compared with normotensive pregnant women. 6. There were significant positive correlations between the levels of prostaglandins and antioxidant activity.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗