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Biomedical subjects

M Chamberlain

Publications and source records attributed to M Chamberlain.

At least 37 records · Page 2Linked to original sources
PubMed1998

Association of dietary fish and n-3 fatty acid intake with hemostatic factors in the coronary artery risk development in young adults (CARDIA) study.

Hemostatic factors play an important role in the complications of ischemic heart and vessel disease. Dietary fats such as n-3 fatty acids have been shown to possibly influence hemostatic factors. However, most studies reporting an inverse association between cardiovascular disease and fish and n-3 fatty acid consumption used supplemental doses of fish oil or intakes exceeding the typical amount consumed by the US population. This report examined the associations of usual intakes of fish, linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid with fibrinogen, factor VII, factor VIII, and von Willebrand factor in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. The analyses reported here included 1672 black and white men and women aged 24 to 42 years in 1992 to 1993. After adjustment for age, body mass index, diabetes, number of cigarettes smoked per day, race, and energy and alcohol consumption, no significant associations were observed between those who consumed no fish versus those who consumed the highest level of dietary fish with respect to fibrinogen, factor VIII, or von Willebrand factor for any race-sex group. Comparisons of tertile 1 versus tertile 3 for dietary linolenic acid, eicosapentaenoic acid, and docosahexaenoic acid were also not significantly associated with fibrinogen, factor VII, factor VIII, or von Willebrand factor for any race-sex group. These data suggest that customary intakes of fish and n-3 fatty acids in populations that generally do not consume large amounts of these food items are not associated with these hemostatic factors.

Adult↗
PubMed1998

Validation of alternative methods for toxicity testing.

Before nonanimal toxicity tests may be officially accepted by regulatory agencies, it is generally agreed that the validity of the new methods must be demonstrated in an independent, scientifically sound validation program. Validation has been defined as the demonstration of the reliability and relevance of a test method for a particular purpose. This paper provides a brief review of the development of the theoretical aspects of the validation process and updates current thinking about objectively testing the performance of an alternative method in a validation study. Validation of alternative methods for eye irritation testing is a specific example illustrating important concepts. Although discussion focuses on the validation of alternative methods intended to replace current in vivo toxicity tests, the procedures can be used to assess the performance of alternative methods intended for other uses.

Animal Testing Alternatives↗
PubMed1998

Evaluation of a midwifery birthing center in the Canadian north.

An evaluation of a midwife-operated community birthing center was conducted to identify whether it would be safe, cost-effective, and psychologically and socially satisfying for Inuit women in one community in the Northwest Territories. Two nurse-midwives provided antenatal and postnatal care to all pregnant women and delivered those designated as 'low risk' for complications. Another community similar in size but with no community birthing was used for comparison of the three indices. Data were gathered on reproductive histories and pregnancy risk profiles of all women giving birth in a one-year period. The financial costs were calculated for those women transferred out to hospital for delivery and compared with those who stayed in the community. Pregnant women and their partners in both communities, health staff, and community members were interviewed for their feelings and concerns about the birthing services. Preliminary findings suggest that with experienced midwives community births are safe. A minimum of 25 births is required in the community for this project to be cost effective. The women who had their infants in the community expressed satisfaction for a number of reasons.

Arctic Regions↗
PubMed1997

Challenges of clinical learning for student midwives.

OBJECTIVE: to identify factors which affect the learning of clinical skills by student midwives. DESIGN: ethnographic, grounded theory. SETTING: a large urban maternity hospital and its community area in the south of England. PARTICIPANTS: student midwives, midwives, midwifery managers and teachers. DATA COLLECTION: by observation in clinical settings and interviews. KEY CONCLUSIONS: observation, indirect learning and trial and error were the strategies used by midwives and students in order to obtain competency in clinical skills. However, anxiety, because of inadequate instruction and supervision and poor communication, interfered with learning and students felt ill prepared to function as midwives. IMPLICATIONS FOR PRACTICE: clinical midwives need to be educated to facilitate the transfer of theoretical learning into clinical practice, and teachers need to re-learn the experience of being a clinical midwife.

Anxiety↗
PubMed1997

IRAG working group 1. Organotypic models for the assessment/prediction of ocular irritation. Interagency Regulatory Alternatives Group.

The brief of the Organotypic Models Working Group was to review data submitted to the Interagency Regulatory Alternatives Group on the use of isolated eyes and components of the eye used to predict eye irritation potential. Data submissions were received on four test systems: the isolated rabbit eye (one submission), the isolated chicken eye (one submission), the bovine cornea (eight submissions) and the cultured bovine lens (one submission). On the basis of the data submitted on each test it was concluded that the isolated rabbit eye test as performed was capable of screening for severe eye irritants, but overall was of no practical value for determining irritation potential across the full range; that the isolated chicken eye test as performed showed promise as a method of predicting eye irritation potential, but the database was too small and needed expanding; that the bovine corneal opacity test had an extensive database and overall performed reasonably at screening out severe irritants and performed well for assigning relative potencies; and that the bovine lens test should be researched further to demonstrate its utility. The overall conclusion drawn was that the isolated eye tests and the bovine corneal opacity test can be used now to screen for severely irritating materials. However, it would be unwise to rely solely on these organotypic methods to provide evidence of lack of eye irritation hazard.

Animal Testing Alternatives↗
PubMed1997

The classification of skin irritants by human patch test.

The human 4 hour patch test provides an opportunity to identify substances with significant skin irritation potential without recourse to the use of animals. The protocol is designed to avoid the production of more than mild irritant reactions and meets the highest ethical standards. This paper provides the background to the development of the method and comments on its performance in the light of recent intra- and inter-laboratory investigations. In particular, the value of the method in providing 'gold standard' data for the identification of those substances (or preparations) which should, or should not, be classified as irritant to skin in European legislation is discussed. On the basis of the published data and supplementary investigations, recommendations are made on both the conduct and interpretation of the human 4 hour patch test. Finally, the lack of any necessity for formal validation of this assay is addressed.

Health Planning Guidelines↗
PubMed1997

A Baby-Friendly Hospital initiative in northern China.

In the People's Republic of China, an approach has been adopted to ensure that all children born as a result of the one-child policy are healthy. The World Health Organization/United Nations Children's Fund (WHO/UNICEF) has encouraged the Chinese Government to embrace this philosophy. Part of this approach has resulted in an attempt to increase the breastfeeding rates. This report describes a visit by two nursing faculty members of a Canadian university to an urban hospital maternity unit in the northeast of China, where the staff were attempting to incorporate this philosophy into their maternity care with the assistance of nursing faculty members from the local university. The method chosen to integrate this philosophy was the Baby-Friendly Hospital Initiative initiated by WHO/UNICEF.

Breast Feeding↗
PubMed1997

Breastfeeding: a course for health professionals.

Breastfeeding advocates say that breastfeeding is health promotion in its purest form. Its considerable health benefits to the infant and the mother are well documented. Recent research has identified breastfeeding as a key factor in the prevention of sudden infant death syndrome and increased cognitive functioning. As a method of feeding, breastfeeding offers immediate economic advantages to the parents and long term economic savings to society. One author reports that the exclusive breastfeeding of infants for four months could save the Province of Ontario at least $862,000 a year just by reducing the need for the treatment of otitis media. Another researcher calculated the cost of treating 150 bottle-fed babies hospitalized for gastroenteritis at $450,000 Canadian, while reminding us that "hospitalization for gastroenteritis is almost unknown for exclusively breastfed infants." With all these known benefits, why is breastfeeding not more prevalent among Canadian mothers?

Breast Feeding↗
PubMed1996

The local lymph node assay: status of validation.

For the prediction of skin sensitization potential of substances, the local lymph node assay (LLNA) is an alternative to the widely used guinea pig tests. Over a 10-yr period this method has undergone extensive development, evaluation and validation. In this commentary, the quality of this validation is examined. It is concluded that the LLNA has successfully passed through all reasonable validation stages. It provides a reliable and relevant source of predictive skin sensitization data which, unlike results from guinea pig tests, are reproducible from laboratory to laboratory. Thus, it is now ready for acceptance as a viable and complete alternative to traditional methods, offering substantial opportunities for reduction in animal usage and improved animal welfare without compromising standards for the identification of significant skin sensitizers.

Allergens↗
PubMed1996

T-cell infiltration of primary CNS lymphoma.

We stained 13 primary CNS lymphomas (PCNSLs) (six from patients with AIDS, seven from immunocompetent patients) with a panel of antibodies to T cells (pan T cell [CD3], T helper cell [CD4], T suppressor cell [CD8], delta/delta cell [CD4-8-]), B cells (CD20), hematopoietic cells (T200), and NK cell (CD56). We estimated the percentage of tumor cells staining with each antibody. All tumors were B-cell lymphomas. The non-AIDS tumors showed a significant infiltration with CD3+ cells (mean of 10.82% of total cells). The AIDS patients' tumors showed a smaller percentage of CD3+ infiltrating cells (mean, 4.88% of total cells) (p<0.01). CD4+ cells were 9.11% of the total hematopoietic cells in the non-AIDS patients and 3.13% in AIDS patients (p<0.01). AIDS patients showed some CD8+ cells (0.3%), which was significantly higher than in immunocompetent patients (0%) (p<0.05). Very few tumor cells stained with the NK cell and delta/delta cell markers. Both immunocompetent and AIDS patients with PCNSL exhibit significant CD3+ and CD4+ cell infiltration of their tumors; this infiltration is significantly lower in AIDS patients. AIDS patients show a minor CD8+ cell infiltration of their tumors. These results on PCNSL are different from systemic lymphomas, which show a higher CD4 and CD8 cell infiltration, and may offer insights into the more aggressive nature of AIDS-related PCNSL.

Antigens, CD↗
PubMed1996

Breastfeeding: a course for health professionals.

Breastfeeding advocates say that breastfeeding is health promotion in its purest form. Its considerable health benefits to the infant and the mother are well documented. Recent research has identified breastfeeding as a key factor in the prevention of sudden infant death syndrome and increased cognitive functioning. As a method of feeding, breastfeeding offers immediate economic advantages to the parents and long-term economic savings to society. One author reports that the exclusive breastfeeding of infants for four months could save the Province of Ontario at least $862,000 a year just by reducing the need for the treatment of otitis media. Another researcher calculated the cost of treating 150 bottle-fed babies hospitalized for gastroenteritis at $450,000 Canadian, while reminding us that "hospitalization for gastroenteritis is almost unknown for exclusively breast-fed infants." With all these known benefits, why is breastfeeding not more prevalent among Canadian mothers?

Breast Feeding↗
PubMed1995

An alternative strategy to the use of guinea pigs for the identification of skin sensitization hazard.

For over half a century, guinea pig methods have dominated the field of toxicology concerned with the identification of skin sensitizers. Specific protocols, for example the guinea pig maximization test (GPMT), have been pre-eminent in the identification of skin sensitization hazard for regulatory purposes. However, there are increasingly several forces driving change, not least animal use/welfare considerations. In response to this and to address the need for a rapid screen for chemical allergens, an alternative strategy has been developed. In the first instance, a chemical is assessed by a computer-based expert system. This system is constructed from some 50 rules describing the key chemically reactive substructures of known skin sensitizers. The output from the expert system is also evaluated in the light of the understanding of the skin penetration characteristics of the chemical. In this way, and without use of animals, the likelihood that a chemical represents a skin sensitization hazard is assessed based on the two key characteristics of a skin sensitizer: (1) its direct or indirect ability to react with skin protein (i.e. does it contain a structural alert?); and (2) the ability of the chemical to partition into the appropriate epidermal compartment. When the chemical does possess a structural alert and has the capacity to penetrate skin sufficiently, then it may be regarded as a potential skin sensitizer. Subsequent to this screening phase, if necessary the chemical may be assessed in the murine local lymph node assay. This assay is quicker and cheaper than traditional guinea pig assays and importantly is less stressful to the fewer animals that it requires. The assay is well validated and produces objective results which are equivalent to the GPMT in terms of identifying significant skin sensitization hazard. In this paper, the above strategy is described in more detail, focusing on its relevance to hazard identification and its value in animal welfare terms. It is concluded that the strategy provides an important opportunity for both substantial reduction and refinement of animal use in a manner which will not compromise the existing standard of classification and labelling of skin sensitization hazard in the European Union.

Animal Testing Alternatives↗
PubMed1994

Identification of irritation and corrosion hazards to skin: an alternative strategy to animal testing.

To date the use of in vitro/alternative tests to achieve formal classification in the EEC of the toxic properties of new substances is very limited. An opportunity exists in the area of skin irritation/corrosivity to adopt a strategic approach which will limit the need to use animals. The approach would involve use of human skin in vitro to identify corrosive materials followed by ethically approved human patch testing. In the patch test, the irritation potential of the substance or preparation would be judged against a suitable positive irritant control. In addition to the avoidance of the use of animals, a further benefit would be that use of human skin should lead to a more relevant classification of skin irritation/corrosion hazard for humans.

Animal Testing Alternatives↗
PubMed1994

MR of the spine in Guillain-Barré syndrome.

MR examination of the spine after injection of gadopentetate dimeglumine showed enhancement of the cauda equina in a case of Guillain-Barré syndrome. These MR observations may help confirm the diagnosis of Guillain-Barré syndrome.

Cauda Equina↗
PubMed1993

Vertebral collapse with quadraparesis due to metastatic gliobla multiforme: case report and review of the literature.

A case is reported of a patient rendered quadraparetic following collapse of a cervical vertebra due to neoplastic invasion by metastatic glioblastoma multiforme. The case is discussed in light of a review of the world literature regarding the clinical incidence and significance of metastasis of glial tumors. It is recommended that all patients with high grade glial tumors who complain of back pain be evaluated with plain radiographs and MRI of the spine or 99Tc bone scan. The management of pathologic spine fractures from metastatic glial tumors with accompanying spinal instability or spinal cord compression due to intracanalicular bone should aim for immediate surgical decompression and stabilization followed by involved field irradiation.

Adult↗
PubMed1993

Expression of Epstein-Barr virus proteins in primary CNS lymphoma in AIDS patients.

We examined the expression of the Epstein-Barr virus (EBV)-induced proteins (LMP [latent membrane protein], EBNA-2, and CD23) and a lytic protein, viral capsid antigen (VCA), in five acquired immune deficiency syndrome (AIDS)-related primary CNS lymphomas (PCNSLs). We compared that expression with the expression of the same proteins in PCNSL from six immunocompetent patients and severe combined immune deficiency (SCID) mouse brains injected with EBV-infected lymphoblastoid cell lines (LCLs). Brain biopsy tissue from an AIDS patient with progressive multifocal leukoencephalopathy (PML) and a normal brain was also studied. Three of the AIDS PCNSLs expressed both human immunoglobulin kappa and lambda light chains and two expressed lambda light chain only. All non-AIDS-related PCNSLs expressed a single light-chain isotype. All five AIDS-related PCNSLs expressed LMP-1 (> 40%), EBNA-2 (> 60%), and VCA (1 to 5%) of tumor cells. These proteins were similarly expressed in the SCID/human chimeras. None of the PCNSLs from immunocompetent subjects, the normal brain, or the brain of the patient with PML expressed these proteins. PCNSL in AIDS patients bears greater similarity to EBV-infected LCLs than to PCNSL from immunocompetent patients.

Animals↗