Search PubMed⌕ Search

Biomedical subjects

J Stanford

Publications and source records attributed to J Stanford.

At least 37 records · Page 2Linked to original sources
PubMed1994

The apparent distance of interior and exterior corners: a test of Gregory's misapplied size constancy explanation for the Mueller-Lyer illusion.

Key to Gregory's misapplied size constancy explanation for the Mueller-Lyer illusion is the assumption that subjects perceive the central line segment of the fins-out figure, which is analogous to an interior corner, as projecting from a more distant object than does the central line segment of the fins-in figure, which is analogous to an exterior corner. We examined the validity of this assumption by having 20 college students judge the relative distance of three-dimensional model corners, presented in a monocular viewing box. The interior corner was perceived to be nearer than the exterior corner, indicating that the key assumption in Gregory's theory is either false or unfalsifiable.

Adult↗
PubMed1991

Modulation of pristane-induced arthritis by mycobacterial antigens.

Several prominent mycobacterial protein antigens involved in antibody and T cell responses have been identified as members of highly conserved heat shock protein families. In particular, immune responses to the mycobacterial 65 kD heat shock protein (hsp65) have been implicated in the pathogenesis of autoimmune diseases both in experimental animal models and in man. Additionally, hsp65 has been shown to modulate the course of autoimmune disease in such experimental animal systems. In this report, we have examined the synthesis of heat shock proteins by a fast growing mycobacterial strain, M. vaccae, in heat stressed cultures and used the pristane induced arthritis model to investigate the immunoprophylactic and immunotherapeutic potential of heat killed M. vaccae. Heat shock of M. vaccae cultures at 48 degrees C demonstrated a 43-fold increase in hsp65 over that expressed at 37 degrees C. It is therefore suggested that heat killed M. vaccae contains sufficient hsp that can be presented in the context of appropriate adjuvant properties for use as an effective immunomodulatory agent. Immunisation experiments with M. vaccae revealed that protection or exacerbation of pristane induced arthritis was dependent on the dose (given in an oil or aqueous suspension), route and time of immunisation. In addition, it was demonstrated that the development of arthritis correlated with high levels of agalactosyl IgG and that "protected" animals had significantly depressed levels.

Animals↗
PubMed1989

A biophysical approach to capillary permeability.

In this preliminary report, the capillary leakage that occurs after scald injury is considered a biophysical phenomenon and is treated by sealing the "pores," or endothelial gaps, in the capillary membranes with biodegradable macromolecules of the appropriate size and shape. We have measured albumin leakage from standardized scald burns in the rat jejunum with and without variously sized fractions of intravenous macromolecules of hydroxyethyl starch (HES) used as a sealing agent. The observed reduction of albumin leakage from injured capillaries was attributed to the sealing effect. The fraction HES (Fm) with molecular weights of 100,000 to 300,000 daltons performed significantly better (p less than 0.05) as a sealing agent when compared with HES (F1) fraction molecular weights of 300,000 to 3.4 million daltons, HES (Fs) molecular weight less than 50,000 daltons, and two control groups receiving the intravenous Ringer's lactate solution or serum albumin 5%. This capillary sealing phenomenon was shown to be independent of colloid osmotic pressure effect. It is believed to be related to the size and the shape of the noncharged macromolecules.

Animals↗
PubMed1987

Testicular self-examination: teaching, learning and practice by nurses.

Testicular cancer is increasing in incidence, is now the commonest solid tumour in men aged 20-34 years and has a better prognosis when detected and treated early. Testicular self-examination is an effective self-screening procedure that is easily taught, learnt and practised. The aim of this study was to discover the extent of the teaching, learning and practice of this procedure by nurses. The data were collected by means of a questionnaire which was sent out to 60 nurses of various grades in one Sussex hospital. Nurses' knowledge of testicular self-examination was found to be better amongst men than women, although over a half of female nurses did know of it. Their knowledge of groups at high risk of testicular cancer was incomplete. Whilst two-thirds of nurses saw the teaching of testicular self-examination as part of their role as health educators, very few had in fact taught it. It appeared that most male nurses do self-examine on a regular basis. The results indicate that nurses need to accept their responsibilities as health educators. Testicular self-examination should become an integral part of nurse training. Facilities and materials should be made available to assist nurses in disseminating such information.

Adult↗
PubMed1986

Vitamin D3, gamma interferon, and control of proliferation of Mycobacterium tuberculosis by human monocytes.

Previous studies have shown that recombinant interferon gamma (IFN-gamma), crude T cell supernatants, or appropriate T-cell lines can cause total inhibition of the growth of M. tuberculosis inside murine peritoneal macrophages. In similar experiments with human monocytes much smaller effects are seen. This could be due to the relative immaturity of these cells. Because dihydroxy vitamin D3 (1,25-(OH)2 D3) can cause phenotypic differentiation of immature leukemic lines into macrophage-like cells, we have explored the possibility that exposure to cholecalciferol metabolites in vitro might increase the ability of monocytes to control proliferation of M. tuberculosis, or cause monocytes to mature into cells able to respond appropriately to IFN-gamma. Incubation of monocytes with three cholecalciferol metabolites induced anti-tuberculosis activity to an extent that correlated with their binding affinities to the intracellular receptor protein for the derivatives. 1,25-(OH)2 D3 also primed monocytes for phorbol myristate acetate-triggered reduction of nitroblue tetrazolium. The effects were additive rather than synergistic with those of IFN-gamma. Monocytes incubated with IFN-gamma developed 25-OH D3 1-hydroxylase activity, detected by conversion of tritiated 25-(OH) D3 to a more polar metabolite which coeluted with 1,25-(OH)2 D3 on straight and reverse-phase HPLC. The latter is a more active form in vivo. These findings help to explain claims for the efficacy of vitamin D in the treatment of some forms of tuberculosis, and also the occasional finding of raised serum calcium, and disturbed vitamin D metabolism in these patients.

Cells, Cultured↗
PubMed1986

The cellular responses of tuberculosis and leprosy patients and of healthy controls in skin tests to 'new tuberculin' and leprosin A.

The density and distribution of T4 and T8 lymphocytes and of monocyte/macrophages at the site of skin tests with mycobacterial antigens was studied in pulmonary tuberculosis and leprosy patients and in healthy controls. Most of the inflammatory cells were located in perivascular and periappendicular foci in the dermis: the percentage of the dermis occupied by focal infiltrate was unrelated to the clinical measurement of the area of induration. There was a less intense diffuse infiltrate in the dermis between the foci, most marked in the papillary dermis and lessening progressively in deeper layers. In patients, diffusely infiltrating lymphocytes were more numerous (mainly due to an excess of T8 cells) in relation to extracts of the pathogen causing their disease than to extracts of the other organism: T8 cells were particularly numerous in reactions to Leprosin A in three of four partly treated leprosy patients who had been classified as tuberculoid at the time of diagnosis. The density of diffusely infiltrating macrophages showed a similar density gradient and selective concentration in response to active disease pathogens. However these cells were less numerous in partly treated leprosy patients than in controls and most frequent in untreated pulmonary tuberculosis patients. Selective migration of monocyte/macrophages and, to a lesser extent T8 cells, appears to be a prominent feature in the reaction of patient with active mycobacterial disease to antigens derived from the causative organisms: this suggests that it might become possible to distinguish direct reactions from cross-reactions in human delayed hypersensitivity reactions by identification of these histological features.

Adult↗
PubMed1985

Classical heatstroke: clinical and laboratory assessment.

We reviewed the clinical and laboratory characteristics of 34 patients who had classical heatstroke during the Kansas City heat wave of 1980. The patients were elderly, predominantly black, and of low socioeconomic class. Overall mortality was 18%, with 9% of patients exhibiting severe residual neurologic deficit; 73% had full recovery. Patients with coma, temperature greater than or equal to 108 F (42.2 C), severe hypotension, coagulopathy, and need for respiratory assistance were at highest risk of death. Associated disease was common (67%), with hypertension (32%), diabetes (21%), and alcoholism (21%) being most frequent. Medications known to predispose to heatstroke were used by 56% of patients. Hematologic abnormalities were nonspecific, and clinical evidence of renal or hepatic failure was rare. Hyponatremia, hypokalemia, hypocalcemia, hypomagnesemia, hypophosphatemia, and elevated levels of creatine phosphokinase and glucose were frequent but did not correlate with outcome. The predominant arterial blood gas abnormality was metabolic acidosis or a combined metabolic acidosis and respiratory alkalosis.

Aged↗