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Biomedical subjects

M Lock

Publications and source records attributed to M Lock.

At least 19 recordsLinked to original sources
PubMed2006

Assessing the prognostic significance of transrectal ultrasound extracapsular extension in prostate cancer.

AIMS: To determine the prognostic value of transrectal ultrasound (TRUS)-detected extraprostatic disease for prostate cancer in patients receiving radical external-beam radiation therapy (EBRT). MATERIALS AND METHODS: A chart review of 181 patients treated with radical EBRT for prostate cancer was conducted. All patients underwent TRUS assessment by one radiologist. The median radiation dose delivered to the prostate was 66 Gy (range 53-70 Gy) in 33 fractions (range 20-39 fractions). Median follow-up time for all patients was 6.5 years. Sixty-four (35%) out of 181 patients were found to have extracapsular disease on TRUS. Clinical relapse was defined as the first occurrence of either salvage hormonal therapy administration by the treating oncologist or clinical, radiological, and/or pathologic evidence of recurrent or progressive disease. In terms of biochemical failure, two prognostic variable analyses were carried out using both the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus guidelines and the Houston definition of biochemical failure. The primary end point for the prognostic variable analyses was time to first clinical or biochemical failure (CBF). RESULTS: For time to CBF using the ASTRO consensus guidelines for biochemical failure, univariable analysis revealed that the prostate-specific antigen (PSA) (P = 0.018), clinical T stage (P = 0.002), Gleason score (P = 0.021), adjuvant hormonal therapy (P = 0.032) and TRUS T staging (P = 0.0001) were statistically significant prognostic factors. On multivariable analysis, clinical T stage (P = 0.051) was of borderline statistical significance, whereas PSA (P = 0.036), TRUS T stage (P = 0.0002) and adjuvant hormonal therapy (P = 0.015) were found to be independent prognostic factors. For time to CBF using the Houston definition of biochemical failure, univariable analysis revealed that PSA (P = 0.001), Gleason score (P = 0.026) and prostate volume (P = 0.013) were statistically significant prognostic factors. On multivariable analysis, PSA (P = 0.002), Gleason score (P = 0.012), and adjuvant hormonal therapy (P = 0.041) were found to be independent prognostic factors. TRUS T staging was not found to be independently significant. CONCLUSIONS: A clear role for TRUS staging as an independent prognostic factor, in the setting of other more established variables, such as Gleason grade, PSA, and digital rectal examination (DRE) T stage, was not confirmed in this study, population.

Aged↗
PubMed2004

Prognostic factors in brain metastases: can we determine patients who do not benefit from whole-brain radiotherapy?

AIMS: Whole-brain radiotherapy (WBRT) is a standard treatment recommendation for patients with brain metastases. The goal of treatment is symptom control, which in the short run can be often achieved by steroids. Patients with a short life expectancy may not derive benefit from the addition of radiation. The ability to identify this group would aid the decision of whether to recommend WBRT. MATERIALS AND METHODS: Data on all patients referred for WBRT to palliative radiotherapy teams at two comprehensive cancer centres were prospectively collected over a 2-year period. The most frequent radiation dose and fractionation was 2000 cGy in 5 fractions over 1 week. Multivariate logistic regression analysis using forward stepwise selection process was used to develop a prediction model for early death (before 8 weeks). The variables considered were sex, performance status, primary disease, weight loss, age, time from primary diagnosis to brain metastases diagnosis, number of metastatic sites and Radiation Therapy Oncology Group (RTOG) recursive partitioning analysis (RPA) status. RESULTS: Two hundred and seventy-five patients with brain metastases were assessed. The median follow-up was 19 weeks, and estimated median overall survival was 5.3 months. Multivariate regression revealed Eastern Cooperative Oncology Group (ECOG) performance status and number of metastatic sites to be significant predictors of early death. The odds ratios were 2.38 (95% confidence interval [CI] 1.77-3.19) and 1.39 (95% CI 1.07-1.81), respectively. Sixty-eight per cent of patients could be correctly classified; however, 55% would have been incorrectly predicted to die early. CONCLUSIONS: Poor performance status and number of metastatic sites are useful predictors of early death. A regression model was highly predictive overall, but this was primarily due to a high negative predictive value of 86%. The ability to predict patients who would die early (positive predictive value) was only 45%. Thus, despite the understanding that we are over-treating a subset of patients, further research is required to identify patients who do not require radiotherapy.

Adult↗
PubMed2001

The new chimaera: the industrialization of organ transplantation. International Forum for Transplant Ethics.

Clinical organ transplantation has evolved through advances in patient care in parallel with investigations in associated biologies. It has developed from a cottage industry to an important medical specialty driven increasingly by the availability of newer and more effective immunosuppressive drugs, and dependent on consistently close collaborations between university-based clinical scientists and the pharmaceutical industry. Particularly during the past decade, however, this industry has undergone striking changes, consolidating into huge multi-national corporations, each competing for patients, their doctors, and for support of the allied hospitals. Because of the growth of "Big Pharma," the relationship between academia and industry has changed. There have been many advantages to such mutually dependent interactions. A combination of university-based expertise and the specialized knowledge and resources of industry have produced important scientific gains in drug development. Commercial sponsorship of applied research has been crucial. The orchestration of multicenter controlled clinical drug trials has provided invaluable information about the effectiveness of newer agents. But there are also disadvantages of increasing concern. Indeed, the power of "Big Pharma" in many medical fields including transplantation is such that presentation of data can be delayed, adverse results withheld, and individual investigations hampered. Clinical trials may be protracted to stifle competition. Monetary considerations may transcend common sense. Several measures to enhance the clinical relationship between the pharmaceutical industry and those involved with organ transplantation are suggested, particularly the use of third party advisors in the production of clinical trials, support for more basic research and in the dissemination of results. In this way, the increasingly problematic phenomenon of commercialization of the field of transplantation can be tempered and controlled.

Drug Industry↗
PubMed2001

Analysis of protein expression from within the region encoding the 2.0-kilobase latency-associated transcript of herpes simplex virus type 1.

During latent infections of sensory neurons, herpes simplex virus type 1 gene expression is restricted to the latency-associated transcripts (LATs). The association of the stable 2.0-kb LAT intron with polysomes has suggested that it might represent a novel mRNA. In this work, we investigated expression of 2.0-kb LAT open reading frames (ORFs) by inserting the gene for green fluorescent protein (GFP) within the 2.0-kb LAT sequence, both within a LAT expression plasmid and in the context of the virus. Upon transient transfection of cells of both neuronal and nonneuronal origin with LAT-GFP expression vectors, low-level GFP fluorescence was distributed over the cell cytoplasm and likely resulted from infrequent initiation at a GFP AUG codon, on either unspliced or alternately spliced LAT RNAs. A second nucleolar GFP expression pattern which resulted from fusion of GFP to a conserved ORF in exon 1 of the LAT gene was also observed. However, the abundant expression of this fusion protein was dependent upon an artificially added translation initiation codon. Expression was much reduced and restricted to a small subset of transfected cells when this initiator codon was removed. Neither the 2.0-kb LAT-GFP intron itself nor transcripts originating from the latency-associated promoter 2 (LAP2) were responsible for GFP expression. Abundant alternate splicing involving the 1.5-kb LAT splice acceptor and including splicing between the 1.5-kb LAT splice donor and acceptor, was observed in the nonneuronal Cos-1 cell line. Contrary to the results of our transfection studies, GFP expression could not be detected from a LAT-GFP virus at any stage of the infection cycle. Our results suggest that the inhibition of LAT ORF expression during viral infection occurred primarily at the level of translation.

5' Untranslated Regions↗
PubMed2001

The tempering of medical anthropology: troubling natural categories.

This article reviews an approach in medical anthropology that commenced in the early 1980s and that continues to the present day in which biomedical knowledge and practices are systematically incorporated into anthropological analyses. Discussion then focuses on contributions made by feminists and medical anthropologists to the literature on medicalization and resistance, illustrating how the ethnographic approach has been crucial in critically reconceptualizing and situating these concepts historically and cross-culturally. The concept of local biologies is introduced in the third section of the article in creating the argument that the coproduction of biologies and cultures contributes to embodied experience, which, in turn, shapes discourse about the body. Subjective reporting at menopause provides an illustrative case study of local biologies in action. The final part of the article takes up the question of the moral economy of scientific knowledge. Comparative ethnographic work in intensive care units in Japan and North America reveals how a moral economy is put into practice in connection with brain-dead bodies and the procurement of organs from them. Medical anthropological contributions to policy making about biomedical technologies is briefly considered in closing.

Anthropology, Cultural↗
PubMed2001

Disseminated intravascular coagulation and PC-SPES: a case report and literature review.

BACKGROUND: PC-SPES is a herbal remedy gaining acceptance amongst prostate cancer patients and health care providers due to credible laboratory and clinical studies. However, PC-SPES has not been assessed in the standard rigorous approval process mandated for conventional agents. OBJECTIVES: To present a case of a patient with prostate cancer who, while using PC-SPES, developed disseminated intravascular coagulation (DIC). A review of the literature was conducted to determine if there is a relationship between PC-SPES and hemorrhagic disorders. METHODS: Searches were conducted in MEDLINE (1966-December 2000) and the Cochrane Collaboration's database. RESULTS: There are 116 clinical and laboratory based studies of PC-SPES published to date. There are no randomized controlled trials. Clinical studies have demonstrated a significant reduction in prostate specific antigen (PSA) levels within 6 weeks. Improved quality-of-life, reduction in the volume of tumor deposits and reduction in analgesic use has been demonstrated in hormone refractory patients. Laboratory studies suggest that the beneficial effects of PC-SPES are unrelated to physiologic estrogens. However, PC-SPES has a side-effect profile similar to diethylstilbestrol. There is data demonstrating a <5% risk of thromboembolic events, but this is the first report of DIC. CONCLUSION: The study of PC-SPES is in its infancy. This case may serve as a cautionary note to health care providers and patients regarding herbal remedies. Those using PC-SPES should have an increased level of surveillance for bleeding disorders.

Aged↗
PubMed2000

Evidence of Vibrational-Induced Rotational Axis Switching for HD(12)C(16)O: New High-Resolution Analysis of the nu(5) and nu(6) Bands and First Analysis of the nu(4) Band (10-µm Region).

Using new high-resolution Fourier transform spectra recorded in Giessen in the 8-12 µm region, a more extended analysis of the nu(5) and nu(6) bands and the first high-resolution study of the nu(4) band of HDCO were performed. As pointed out previously [M. Allegrini, J. W. C. Johns, and A. R. W. McKellar, Can. J. Phys. 56, 859-864 (1978)], the energy levels of the 5(1) and 6(1) states are strongly coupled by A- and B-type Coriolis interactions. On the other hand, it appeared that weaker resonances involving the energy levels of the 4(1) state with those of the 5(1) and 6(1) states also had to be accounted for. Consequently, the calculation of the energy levels was performed taking into account the Coriolis-type resonances linking the energy levels of the {6(1), 5(1), 4(1)} resonating states. Because of the unusually strong Coriolis interaction between nu(5) and nu(6), a nonclassical behavior of the rotational levels of the 5(1) and 6(1) states was observed and it was necessary to use a new Hamiltonian matrix which possesses, as usual, both A- and B-type Coriolis operators in the 5(1) if 6(1) and 6(1) if 4(1) off diagonal blocks but differs from the classical reduced Hamiltonian which is used commonly for planar C(s)-type molecules. More precisely, it proved necessary to include non-orthorhombic terms in the expansion of the rotational Hamiltonian of the 5(1) and 6(1) states. According to the considerations developed by Watson [J. K. G. Watson, in "Vibrational Spectra and Structure," (J. Durig, Ed.), Chap. 1, Elsevier, Amsterdam, 1977], these non-orthorhombic operators which are not symmetry forbidden are usually removed for semirigid C(s)-type molecules by rotational contact transformations. In the present study, the occurrence of terms in {J(x), J(z)} in the expansions of the rotational Hamiltonians for the 5(1) and 6(1) states indicates that the inertial system of HDCO differs for each of the three {6(1), 5(1), 4(1)} resonating states. Therefore, HDCO becomes a good example of vibrational-induced rotational axis switching (VIRAS) which was already suggested as the mechanism responsible for the enhanced densities of coupled states observed in 2-fluoroethanol [H. Li, S. Erza, and L. A. Philips, J. Chem. Phys. 97, 5956-5963 (1992)]. Copyright 2000 Academic Press.

Journal Article↗
PubMed1999

Higher neonatal morbidity after routine early hospital discharge: are we sending newborns home too early?

BACKGROUND: A growing body of evidence suggests that the trend toward earlier discharge may affect newborn morbidity. The authors assessed how hospital readmission rates were affected by a clinical guideline aimed at discharging newborns from hospital 24 hours after birth. METHOD: A retrospective before-after cohort study was conducted involving 7009 infants born by uncomplicated vaginal delivery at a large level II hospital in Toronto between Dec. 31, 1993, and Sept. 29, 1997. The primary outcome was a comparison of the rate of hospital readmission among newborns before (5936 infants) and after (1073 infants) the early-discharge policy was implemented (Apr. 1, 1997). The causes for readmission were secondary outcomes. RESULTS: Before the early-discharge guideline was implemented, the mean length of stay declined from 2.25 days (95% confidence interval [CI] 2.18-2.32) to 1.88 days (95% CI 1.84-1.92) (p < 0.001). After implementation there was a further decline, to 1.62 days (95% CI 1.56-1.67) (p < 0.001). A total of 126 infants (11.7%) in the early-discharge cohort required readmission by 1 month, as compared with 396 infants (6.7%) in the preguideline cohort (odds ratio 1.86, 95% CI 1.51-2.30). The main reason for early readmission was neonatal jaundice, with a higher rate among infants in the early-discharge cohort than among those in the preguideline cohort (8.6% v. 3.1%; odds ratio 2.96, 95% CI 2.29-3.84). INTERPRETATION: Decreases in newborn length of stay may result in substantial increases in morbidity. Careful consideration is needed to establish whether a reduction in length of stay to less than 24 to 36 hours is harmful to babies.

Cohort Studies↗
PubMed1999

Two elements target SIV Nef to the AP-2 clathrin adaptor complex, but only one is required for the induction of CD4 endocytosis.

The simian immunodeficiency virus (SIV) and human immunodeficiency virus type 1 (HIV-1) Nef proteins induce the endocytosis of CD4 and class I MHC molecules. Here we show that SIV Nef interacts with the AP-2 adaptor complex via two elements located in the N-terminal region of the Nef molecule, but only the N-distal element is required to induce CD4 endocytosis. This N-distal AP-2 targeting element contains no canonical endocytic signals and probably contacts the AP-2 complex via a novel interaction surface. The data support a model where SIV Nef induces CD4 endocytosis by promoting the normal interactions between the di-leucine sorting signal in the CD4 cytoplasmic domain and AP-2, but does not substitute for the CD4-AP-2 adaptor interaction. Neither element is important for the induction of class I MHC endocytosis, thus indicating that different mechanisms underlie the induction of class I MHC and CD4 endocytosis by Nef. In contrast to SIV Nef, HIV-1 Nef interacts with AP-2 via a surface containing a di-leucine endocytosis signal in the C-terminal disordered loop of Nef. The fact that genetic selection maintains similar molecular interactions via different surfaces in SIV and HIV-1 Nef proteins indicates that these interactions have critical roles for the viral life cycle in vivo.

Adaptor Proteins, Vesicular Transport↗
PubMed1999

Detection of human retrovirus 5 in patients with arthritis and systemic lupus erythematosus.

OBJECTIVE: To examine whether human retrovirus 5 (HRV-5) infection is associated with autoimmune rheumatic disease. METHODS: DNA from patients with various disorders including inflammatory diseases and from normal subjects was tested by nested polymerase chain reaction (PCR) for HRV-5 proviral DNA. Positive results were confirmed by DNA sequencing. RESULTS: HRV-5 proviral DNA was detected in 53% of synovial samples from arthritic joints, in 12% of blood samples from patients with rheumatoid arthritis (RA), and in 16% of blood samples from patients with systemic lupus erythematosus. In contrast, it was not detectable by PCR of affected tissues from patients with several other autoimmune diseases and was found in only 1 of >200 tissue specimens obtained at autopsy from non-RA patients. Sequence analysis of the amplified viral segment showed genetic variation between samples with maintenance of the open reading frame, typical of a replicating infectious retrovirus. CONCLUSION: This is the first report of the frequent detection of HRV-5 in any disease. We propose that the possible involvement of HRV-5 in autoimmune and rheumatic disease should be investigated further.

Arthritis, Rheumatoid↗
PubMed1999

A psychiatric trainee's guide to the criminal courts.

This article provides a guide on the criminal justice system in England and Wales to assist psychiatrists who are asked to prepare reports on people subject to criminal proceedings. It describes which sections of the Mental Health Act 1983 are relevant at different stages of the criminal justice process.

Criminology↗