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Biomedical subjects

M Wallace

Publications and source records attributed to M Wallace.

At least 91 records · Page 5Linked to original sources
PubMed1998

Possible protective and pathogenic roles of gamma delta T lymphocytes in HIV-infections (Review).

alpha beta and gamma delta T lymphocytes are largely responsible for the specificity of coordinated immune responses that are of crucial importance for protection from exogenous invaders and elimination of endogenous aberrations. One of the prominent distinguishing characteristics of primate gamma delta T lymphocytes is that most of their T cell receptors for antigen (gamma delta TCRs) are, unlike alpha beta TCRs, capable of recognizing nonpeptidic antigens in an MHC-unrestricted manner. Another interesting feature is that the gamma delta T cell subpopulation displays profound qualitative and quantitative changes in individuals with various infectious diseases. For example, the most frequent human peripheral blood gamma delta T cell subset expressing Vgamma9Vdelta2 TCRs is functionally disabled and numerically decreased in some HIV-infected persons. The nonresponsiveness of Vgamma9Vdelta2 T cells is accompanied by their decreased IFNç and TNFá production. The overall level of gamma T cell activation at different stages of HIV-infection may be clinically relevant. At an initial stage of HIV-infection, the extremely potent antiviral cytotoxic activities of Vgamma9Vdelta2 T cells may limit the viral spread. At later stages of disease, Vgamma9Vdelta2 T cell dysfunction may contribute to the loss of resistance to opportunistic pathogens (such as atypical mycobacteria) and neoplasms (e.g., lymphomas) frequently associated with HIV-infections. Also, it is possible that chronic stimulation of gamma delta T cells may result in immunopathology. In particular, the massive immunologic activation that appears to be the major contributing element of AIDS immunopathogenesis could be, at least in part, driven by gamma delta T cells overstimulated by repetitive exposures to HIV.

HIV Infections↗
PubMed1998

Mucosal transmission of virulent and avirulent lentiviruses in macaques.

Sexual transmission of human immunodeficiency virus provides an efficient mode for virus spread and poses unique challenges to vaccine developers. Host and viral factors that affect transmission have been studied by epidemiological approaches in the human population, and some of these factors have been modeled with experimental infection of nonhuman primates. Basic principles have emerged regarding transmission and viral virulence. These ideas may be beneficial for designing a safe and effective vaccine.

AIDS Vaccines↗
PubMed1998

Preconception care: who needs it, who wants it, and how should it be provided?

BACKGROUND: Preconception care (PC) aims to identify and reduce a number of modifiable factors that can adversely affect pregnancy outcome. AIM: To ascertain both knowledge of the attitudes towards PC among members of primary health care teams (PHCTs) and registered women of childbearing age in a representative sample of general practices in Harrow. METHOD: A questionnaire survey was conducted in a randomly selected group of nine general practices in the London borough of Harrow. Subjects included all relevant health professionals and female patients of childbearing age registered with the practices. RESULTS: A total of 62/88 (70.5%) health professionals and 811 women (1 in 20 of the entire target population) completed the questionnaires. Nurses' knowledge matched that of the doctors, except in the area of genetics. Over 85% of all health professionals believed that PC could be of benefit to both mother and baby. Women were generally well informed; Asian women, those born outside the UK, those who had never been pregnant, and those who had not undertaken education beyond the age of 18 years were significantly less well informed. Health professionals considered PC to be best delivered opportunistically by nurses, and this method appeared to be acceptable to most female patients of childbearing age, although it was significantly less acceptable among Asians. CONCLUSION: Among health professionals and women of childbearing age, there is generally a good level of knowledge of PC, although certain groups are less well informed than others and could benefit from a targeted education approach. Widespread agreement that PC is worthwhile was found among PHCT members, but this view is less strongly held by the female public, with the acceptability of providing PC opportunistically differing significantly between ethnic groups.

Adolescent↗
PubMed1997

Mts4, a non-ATPase subunit of the 26 S protease in fission yeast is essential for mitosis and interacts directly with the ATPase subunit Mts2.

We have isolated a fission yeast gene, mts4(+), by complementation of a temperature-sensitive mutation and show that it encodes subunit 2 (S2) of the 19 S regulatory complex of the 26 S protease. mts4(+) is an essential gene, and we show that loss of this subunit causes cells to arrest in metaphase, illustrating the importance of S2 for mitosis. The Mts4 protein is 48% identical to S2 of the human 26 S protease, and the lethal phenotype of the null mts4 allele can be rescued by the human cDNA encoding S2. We provide genetic and physical evidence to suggest that the Mts4 protein interacts with the product of the mts2(+) gene, an ATPase which has previously been shown to be subunit 4 of the 26 S protease.

Adenosine Triphosphatases↗
PubMed1997

Treatment planning for adenocarcinoma of the rectum and sigmoid: a patterns of care study. PCS Committee.

PURPOSE: To conduct a study of the process of treatment planning and treatment of adenocarcinoma of the rectum and sigmoid in the United States, and to compare survey results to consensus guidelines. METHODS AND MATERIALS: A consensus committee developed guidelines for the radiotherapeutic management of adenocarcinoma of the rectum and sigmoid, and also developed a survey form that was used to gather data to evaluate the practice patterns for patients treated in 1989 and 1990 against the consensus guidelines. Seventy-three facilities were randomly selected for site visits from the 1321 radiation therapy facilities in the US: 21 academic, 26 hospital based, and 26 free standing. During the site visits, the radiotherapy records were examined by the surveyor physicist and radiation oncologist to extract and record the required data. Data collected included items related to treatment specific parameters, including treatment planning considerations. Analyses included stratification as to the types of institutions, academic, hospital based, or free standing. RESULTS: For many treatment parameters there are discrepancies between the patterns of practice determined by the surveys and the consensus guidelines for radiotherapy treatment of adenocarcinoma of the rectum and sigmoid. Significant differences in practice among the stratified institution types were found in only a few parameters.

Adenocarcinoma↗
PubMed1997

Patient self-assessment of complications and quality of life after conformal neutron and photon irradiation for localized prostate cancer.

Although neutron irradiation for prostate cancer has been associated with significant morbidity, pilot data in patients with early stage disease suggested that conformal neutron and photon irradiation was well tolerated without severe complications. A self-assessment questionnaire was mailed to the first 83 patients treated with conformal neutron and photon irradiation to objectively evaluate the impact on quality of life of this regimen. In total, 75 patients (90%) returned the completed questionnaire. These patients had received either 9 neutron Gy (N Gy) plus 38 photon Gy (50 patients) or 10 N Gy plus 38 photon Gy (33 patients) for stage T1/T2 N0 M0 prostate cancer (Gleason score < or = 7). The irradiated volume included the prostate and seminal vesicles with a 1.5 cm margin. Neutrons were delivered as a boost to the prostate only with a non-axial four field beam arrangement. Approximately 50% of the dose to the prostate was from neutron irradiation. Follow-up ranged from 6 to 25 months (median 13 months). The questionnaire used was a validated quality of life instrument used previously in patients treated with surgery or radiation. Prior to irradiation, 29% of patients reported urinary symptoms and 11% had prostate surgery (TURP). At follow-up, 23% reported persistent urinary symptoms. Of these, 21% dripped a few drops of urine, 3% used pads but none leaked > 1 tablespoon/day. One patient underwent surgery to dilate a urethral stricture. Although 55% of patients had gastrointestinal symptoms during radiation therapy, only 26% had persistent symptoms at the time of questioning. These included minor rectal bleeding in 20% and significant hematochezia in 3%. Of the 85% of patients able to obtain full or partial erections prior to irradiation, 87% maintained their potency. Fifteen percent sought treatment for impotence. Overall, at last follow-up, 84% felt little or no physical discomfort, 91% were very satisfied with their treatment, and 97% would choose radiation therapy again. This patient self-assessment questionnaire confirmed that this regimen of conformal neutron and photon irradiation resulted in levels of chronic toxicity acceptable to the patient.

Abdominal Pain↗
PubMed1997

Restraint: some legal implications.

The law in relation to the autonomy and physical integrity of persons is explored in this paper. Charges of assault and battery may result where trespass to the person--that is, unwanted physical contact--occurs. These concepts are discussed in the context of the use of restraining behaviours applied to persons in health-care facilities.

Australia↗
PubMed1997

DBT: a partial D phenotype associated with the low-incidence antigen Rh32.

Eight probands are described with a D phenotype in which a partial D antigen is associated with Rh32 antigen; three of these probands were investigated because of the anti-D in their serum. The partial D lacks epD1-epD5 and epD9 and some epD6/7 and only expresses epD8 and other parts of epD6/7. The strength of the partial D antigen varies between unrelated DBT individuals. The Rh32 antigen of the DBT cells is weaker than that of D(C)(e) cells. Tests on DBT, DFR and R0Har cells with anti-epD6/7 split these monoclonal anti-D into eight patterns of reaction. A new pattern of reactions was observed, presaging a new epitope, but this was not numbered.

Antibodies, Monoclonal↗
PubMed1997

Robotic multimodality stereotactic brain tissue identification: work in progress.

Real-time identification of tissue would improve procedures such as stereotactic brain biopsy (SBX), functional and implantation neurosurgery, and brain tumor excision. To standard SBX equipment has been added: (1) computer-controlled stepper motors to drive the biopsy needle/probe precisely; (2) multiple microprobes to track tissue density, detect blood vessels and changes in blood flow, and distinguish the various tissues being penetrated; (3) neural net learning programs to allow real-time comparisons of current data with a normative data bank; (4) three-dimensional graphic displays to follow the probe as it traverses brain tissue. The probe can differentiate substances such as pig brain, differing consistencies of the 'brain-like' foodstuff tofu, and gels made to simulate brain, as well as detect blood vessels imbedded in these substances. Multimodality probes should improve the safety, efficacy, and diagnostic accuracy of SBX and other neurosurgical procedures.

Animals↗
PubMed1997

Functional gamma delta T-lymphocyte defect associated with human immunodeficiency virus infections.

BACKGROUND: Antiviral cellular immune responses may influence immunological homeostasis in HIV-infected persons. Recent data indicate that V gamma 9/V delta 2 T lymphocytes display potent cytotoxic activities against human cells infected with certain viruses including HIV. Understanding the role of gamma delta T cells in the course of HIV infection may be helpful for designing novel treatment strategies for HIV-associated disorders. MATERIALS AND METHODS: The constitutive recognition of Daudi cells and monoethyl pyrophosphate (Etpp) by peripheral blood V gamma 9/V delta 2 T cells was assessed using a proliferation assay. The cytotoxicity of Daudi-stimulated lymphocyte populations was measured by chromium release assays. The HIV infectivity for gamma delta T cell clones was determined by measuring the levels of HIV p24 in cell supernatants. The effect of in vitro HIV-infection on cytokine mRNA production by gamma delta T cell clones was assessed by PCR. RESULTS: The constitutive proliferative responses of peripheral blood V gamma 9/V delta 2 T cells and the lytic functions of Daudi-expanded lymphoid cells from HIV+ persons were substantially diminished in comparison with those of HIV-seronegative persons. These alterations were present in asymptomatic HIV+ persons prior to substantial alpha beta CD4+ T cell loss. Productive HIV infection of gamma delta T cells in vitro had no measurable effect either on their proliferative response to Daudi stimuli or on the expression of cytokine mRNAs for IFN-gamma, IL-2, IL-4, IL-5, IL-6, IL-10, and IL-13. CONCLUSIONS: The constitutive responsiveness of V gamma 9/V delta 2 T lymphocytes to Daudi and Etpp is severely altered in HIV+ persons. HIV infection of gamma delta T cells in vitro does not substantially change their cytokine expression or antigenic response.

Cell Division↗
PubMed1996

Treatment planning for primary breast cancer: a patterns of care study.

PURPOSE: The 1989 Patterns of Care Study included treatment planning for early breast cancer. A Consensus Committee of radiation physicists and oncologists determined current guidelines and developed questionnaires to determine treatment planning and delivery processes used by the participating institutions (e.g., use of portal films). This article presents and analyzes the results of that survey. METHODS AND MATERIALS: The survey included 449 respondents, distributed as follows: 136 (30%) from Strata I (academic facilities); 169 (38%) from Strata II (hospital based facilities); and 144 (32%) from Strata III (freestanding facilities). The treatment planning procedures surveyed included: whether individualized tissue compensators are used, whether inhomogeneity corrections are used in dose calculations, the use of computerized tomography, whether isodose distributions for external beam tangents and interstitial implants are generated, the use of lymphoscintigraphy, immobilization devices, simulations, portal films, etc. RESULTS: The survey results demonstrated that out of 305 patients from Strata I and II institutions, 237 (78%) had simulated tangential fields. Consistent with this finding is that 76% of patients from Strata I and II institutions were immobilized, while only 51% of Strata III patients were. Moreover, only 18 out of the 449 (4%) of cases did not have any type of external beam dose distribution calculated--presumably, in these cases missing tissue compensation would be unlikely. On the other hand, 41% of the Strata II, 27% of Strata III, but only 19% of Strata I (p < 0.0002) cases received CT. Surprisingly, 19% of the Strata I, 35% of the Strata II, and 25% of the Strata III (p = 0.0011) patients received lymphoscintigraphy, perhaps reflecting the use of wide tangents to encompass the internal mammary nodes in these patients. In terms of optimizing treatments, 74% of Strata I, 70% of Strata II, and 78% of Strata III patients had wedges used on both tangential fields, although in 5, 12, and 14%, respectively, no beam modification of any sort was used. Furthermore, it should be noted that in 7% of the Strata I, 23% of Strata II, and 37% of Strata III cases there was no attempt to reduce the divergence of the tangential fields into the lung. On the other hand, if one considers the 135 (of 449) patients where matching of the tangential and supraclavicular fields was applicable, 41% of Strata I, 22% of Strata II and 46% of Strata III patients had those fields matched in a vertical plane, which would involve sophisticated alignment procedures. Quality control of treatment delivery was high: 97% of all surveyed received portal films at least once. The use of thermoluminescent dosimetry (TLD) to measure the dose to the contralateral breast was of little interest: only 4 of the 305 Strata I and II patients received in vivo measurements. CONCLUSIONS: This national survey has established the patterns of treatment planning for early breast cancer. It shows a generally consistent approach-although a number of statistically significant variations have been identified.

Breast Neoplasms↗
PubMed1996

A conditional lethal mutant in the fission yeast 26 S protease subunit mts3+ is defective in metaphase to anaphase transition.

We have isolated a conditional lethal mutant mts3 in the fission yeast Schizosaccharomyces pombe which at the permissive temperature is resistant to the mitotic poison MBC and at the restrictive temperature is defective in metaphase to anaphase transition. The predicted amino acid sequence of mts3+ is 36% identical with the budding yeast gene NIN1. NIN1 cloned into a fission yeast expression vector can rescue both mts3 temperature-sensitive and null alleles demonstrating that NIN1 is the budding yeast homologue of the fission yeast mts3+ gene. The phenotype of the mts3 null is identical with the mts3 ts mutant demonstrating that the phenotype of the mts3 ts mutant is due to loss of mts3+ function. The deduced amino acid sequences of both mts3+ and NIN1 show homology to peptide sequences obtained from subunit 14 of the 26 S protease purified from bovine or human cells.

Amino Acid Sequence↗
PubMed1996

The legal framework for mental health nursing.

This article sets out basic legal principles underlying the care and treatment of mentally ill clients. Legal considerations are important for nurses, because it is now felt that the care of the mentally ill is as much a legal matter as a medical one. The frequent ordering of compulsory care, detention and administration of medication takes place in a climate of ever-increasing emphasis on autonomy, and has resulted in the need for nurses to ensure that they do not violate clients' human and legal rights. Legislation is concerned not primarily with the finer points of what mental illness is--that is left to the medical profession--but with criteria which warrant the detention and treatment of a person against their will. The article points to international documents which set out principles for the care of the mentally ill, as well as both Commonwealth, state and territory legislation. It summarises the main provisions of these in relation to involuntary detention and treatment, as well as electroconvulsive therapy and psychosurgery. Nurses who care for mentally ill clients need, therefore, to understand in some detail the legislation that applies to them in their professional capacity, as well as the human rights it seeks to protect.

Australia↗