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Biomedical subjects

S S Williams

Publications and source records attributed to S S Williams.

At least 19 recordsLinked to original sources
PubMed2003

Predicting normal lung function in patients with childhood spinal cord injury.

STUDY DESIGN: A prospective observational study. OBJECTIVES: To compare the height and arm span measurements in childhood spinal cord injured (SCI) people and examine the subsequent effect on calculating the predicted lung function using standard formulae and to discuss which of the two measurements is the most appropriate to use in these formulae. SETTING: National Spinal Injuries Centre, Stoke Mandeville Hospital, Aylesbury, UK. METHOD: A total of 12 children had lung function tests performed and at the same time had height and armspan measured. The predicted lung function was calculated twice; once using height and then using arm span and compared. The actual lung function test results were expressed as percentage of the two predicted values, respectively, and compared. RESULTS: The difference between the mean height (1499 mm) and arm span (1649 mm) measurements was significant (P<0.001). In all cases, the arm span measurement was greater than the height. The two predicted lung function values (one calculated using height and the other armspan) were significantly different (P<0.001). When lung function test results were expressed as percentage of the two predicted values they gave a very different interpretation of the results. The actual performance was much lower than the predicted values if arm span, rather than height, was used in prediction equations. CONCLUSION: In childhood SCI, the difference in height and arm span is significant. This affects the predicted lung function values significantly and thus changes the interpretation of the lung function test results. The most appropriate measurement to use in prediction equations (height or arm span) in these subjects is yet to be decided.

Anthropometry↗
PubMed2002

Psychological distress among students from five universities in Sri Lanka.

OBJECTIVE: To determine the proportion of university students that are psychologically distressed when compared to an age and sex matched population sample and to describe the factors that may contribute to their distress. DESIGN: A cross-sectional comparison study. METHODS: The general health questionnaire (GHQ 30), previously validated in Sinhala, was administered as a screening test to random samples of undergraduates in 5 universities. Age and sex matched controls from the respective communities were also administered the screening test. The undergraduates also filled in a pre-tested questionnaire with personal details. Chi-square tests were used to determine statistical significance between groups. RESULTS: Among the undergraduates, 104 (39.8%) had scores for psychological distress whereas only 67 (25.7%) from the community sample had scores for similar distress. This difference was significant (p = 0.0007). A significantly greater proportion (p = 0.009) of those entering from rural schools were psychologically distressed than those from suburban and urban schools, and a greater proportion living in rented rooms and hostels were (p = 0.001) distressed than those travelling from their homes. CONCLUSIONS: The psychological distress among undergraduates was significantly greater than among the general population. More students who enter from rural schools seem to be distressed than those who enter from suburban and urban schools.

Adult↗
PubMed2001

Decreased CD44 standard form expression correlates with prognostic variables in ovarian carcinomas.

Expression of CD44 standard form (CD44s) was evaluated by automated immunohistochemical analysis using the anti-CD44 A3D8 clone in 101 ovarian epithelial neoplasms including 82 primary tumors (64 carcinomas and 18 tumors of low malignant potential [LMP]), 9 lymph node metastases, 8 malignant ascites, and 2 peritoneal implants. Immunostaining was scored semiquantitatively. Tumors were graded according to the FIGO (International Federation of Gynecology and Obstetrics) classification system. Tumor stage and patient survival were determined from the patient records. While 9 of 18 LMP tumors expressed CD44s, only 15 of 64 carcinomas expressed it. In the carcinomas, univariate analysis revealed that decreased CD44s expression correlated with high tumor grade, advanced stage, and shortened survival. Loss of CD44s expression also was noted in the tumor cells in 8 of 9 lymph node metastases, 7 of 8 malignant ascites, and 1 of 2 implants. Multivariate analysis revealed that only tumor stage independently correlated with patient survival. Loss of CD44s expression determined by immunohistochemical analysis is more common in ovarian carcinomas than in LMP tumors; correlates with prognostic variables including tumor grade, stage, and survival; and may have an important role in the dissemination of ovarian cancer.

Adult↗
PubMed2000

Bcl-2 overexpression results in enhanced capacitative calcium entry and resistance to SKF-96365-induced apoptosis.

Although there is evidence that changes in cellular ionic concentrations are important early events in apoptosis, the regulation of ion fluxes across the plasma membrane during this process is poorly understood. We report here that Bcl-2 overexpression results in up-regulation of capacitative Ca2+ entry (CCE) and that SKF-96365, an inhibitor of CCE, is a potent inducer of apoptosis. Cells that overexpress Bcl-2 are resistant to SKF-96365-mediated apoptosis and to its inhibition of CCE. Enhanced CCE can be reversed with ouabain, suggesting that Bcl-2-associated plasma membrane hyperpolarization plays a role in up-regulating CCE and may partially explain the antiapoptotic effect of Bcl-2.

Apoptosis↗
PubMed2000

Breast-conserving radiation therapy using combined electron and intensity-modulated radiotherapy technique.

BACKGROUND AND PURPOSE: To explore the feasibility of a multi-modality breast-conserving radiation therapy treatment technique to reduce high dose to the ipsilateral lung and the heart when compared with the conventional treatment technique using two tangential fields. MATERIALS AND METHODS: An electron beam with appropriate energy was combined with four intensity modulated photon beams. The direction of the electron beam was chosen to be tilted 10-20 degrees laterally from the anteroposterior direction. Two of the intensity-modulated photon beams had the same gantry angles as the conventional tangential fields, whereas the other two beams were rotated 15-25 degrees toward the anteroposterior directions from the first two photon beams. An iterative algorithm was developed which optimizes the weight of the electron beam as well as the fluence profiles of the photon beams for a given patient. Two breast cancer patients with early-stage breast tumors were planned with the new technique and the results were compared with those from 3D planning using tangential fields as well as 9-field intensity-modulated radiotherapy (IMRT) techniques. RESULTS: The combined electron and IMRT plans showed better dose conformity to the target with significantly reduced dose to the ipsilateral lung and, in the case of the left-breast patient, reduced dose to the heart, than the tangential field plans. In both the right-sided and left-sided breast plans, the dose to other normal structures was similar to that from conventional plans and was much smaller than that from the 9-field IMRT plans. The optimized electron beam provided between 70 to 80% of the prescribed dose at the depth of maximum dose of the electron beam. CONCLUSIONS: The combined electron and IMRT technique showed improvement over the conventional treatment technique using tangential fields with reduced dose to the ipsilateral lung and the heart. The customized beam directions of the four IMRT fields also kept the dose to other critical structures to a minimum.

Breast Neoplasms↗
PubMed1996

Engraftment of human tumor-infiltrating lymphocytes and the production of anti-tumor antibodies in SCID mice.

We report here the placement of nondisrupted 1-mm3 pieces of fresh human lung tumor biopsy tissue into the subcutis of severe combined immunodeficient (SCID) mice results in the engraftment of tumor-infiltrating leukocytes (TIL) in all but 5 of 148 mice inoculated with 39 different biopsy tissue specimens. In mice coengrafted with tumor and TIL the normal histologic architecture of the tumor and TIL interface was maintained for up to 22 wk. The TIL in the xenograft were shown to divide and were maintained exclusively at the site of tumor inoculation. It is established here that plasma cells in the TIL population produce Abs that react in western blots with tumor cell lysates. These Abs were shown to react with high and low m.w. proteins derived from both the membrane and cytosolic fractions of tumor cell lysates. The production of human Ig was found to be T cell dependent, and immunohistochemistry and in situ hybridization of DNA, using a human-specific cDNA probe, established the human identity of the tumor and TIL. High levels of human Ig in the sera of mice inoculated with tumor biopsy tissue are associated with the growth arrest of adenocarcinoma xenografts. Our results establish the co-engraftment of human tumors and TIL into SCID mice as new animal model with which to evaluate TIL function and novel therapeutic strategies that are designed to augment TIL anti-tumor activity.

Animals↗
PubMed1996

Restrained eating among adolescents: dieters are not always bingers and bingers are not always dieters.

This study examined individual differences in the relationships among 3 constructs relevant to restrained eating theory-cognitive restraint (dieting), disinhibition (binging), and hunger. Participants were 421 adolescents (158 male, 255 female, and 8 not indicated). Comparisons among subgroups based on scores on the 3 constructs indicated that there were (a) 2 types of frequent dieters-those who follow theoretical predictions and become disinhibited and those who maintain their restraint; (b) 2 types of bingers-those who engage in dieting-induced binging and those who are hungry and disinhibited; and (c) 2 types of low-hunger eaters-those who suppress their hunger and those who eat before they experience much hunger. Implications of the results for restrained eating theory are discussed.

Adolescent↗
PubMed1996

Periradicular healing in response to Diaket root-end filling material with and without tricalcium phosphate.

The healing of the periradicular tissues was evaluated when the polyvinyl resin Diaket with and without tricalcium phosphate was used as surgical root-end filling material. Non-surgical root canal treatment was performed on 56 mandibular premolar roots in mongrel dogs. Following root-end resection, root-end cavity preparations were filled with Diaket, the comparative material, or Diaket in combination with tricalcium phosphate, the experimental material. Postsurgically, healing of the tissues adjacent to the filling materials and in the surrounding surgical site were evaluated at 30 and 60 days. There was virtually no statistically significant difference between the experimental and comparative group at or within the 30- or 60-day period with regard to inflammation, connective tissue formation, root-end encapsulation, cementum formation, or bone apposition. Findings suggest that cementogenesis occurred over both materials. The overall healing of the periradicular tissues was favourable.

Animals↗
PubMed1996

VH and VL gene complexes encoding an anti-spectrin antibody are defined by nucleotide sequencing of cDNA from a hybridoma generated from Hu-PBL-SCID mouse.

Previously we reported that human imunocompetent cells engrafted into scid mice mount a sustained and vigorous humoral immune response to murine erythrocytes. One of the dominant and consistently observed reactivity pattern of these antibodies in immunoblot analysis is with the alpha and beta isoforms of spectrin. In order to define the human xenoreactive response more completely, a hybridoma was generated (from a hu-PBL-scid mouse) whose antibody reacted with two high molecular weight species 225 to 250 kDa. We report here that this conserved antibody species reacts with both the murine and human erythrocyte proteins and cDNA nucleotide sequence analysis of the light and heavy chain genes encoding this antibody reveals that the light chain variable region gene has been previously observed in association with an autoreactive antibody. In addition to characterizing a conserved human B cell clonotype this is the first report of a human monoclonal antibody being generated from the hu-PBL-scid model using the standard hybridoma technology.

Amino Acid Sequence↗
PubMed1995

Human antibody response in human peripheral blood leukocyte/severe combined immunodeficient chimeric model is dependent on B and T cell costimulation via CD40/CD40 ligand.

We have used a human/severe combined immunodeficient (SCID) mouse chimeric model (in which human PBLs are engrafted into SCID mice) to investigate in vivo the role of the CD40/CD40 ligand (CD40L) interaction in the generation of humoral immunity by engrafted human cells. It is established in this work that the thymic dependent, multiclonal, humoral immune response of human lymphocytes to mouse erythrocyte protein Ags is inhibited significantly when CD40/CD40L ligation is prevented in vivo. Suppression of the response was observed with administration of neutralizing Abs specific for either CD40 or CD40L, or with the soluble fusion protein human CD40-Fc. Human anti-mouse erythrocyte Abs and the total human Ig levels in the sera of the SCID mice were suppressed for up to 10 wk when the neutralizing agents were administered at the time of human leukocyte engraftment, i.e., coincident with Ag stimulation, and subsequently at 2 and 4 days after Ag stimulation. These results are the first to demonstrate the ability of CD40/CD40L blocking agents to inhibit the human Ag-specific humoral immune response in vivo, and they sustain the notion that these blocking agents may be utilized clinically to eliminate immune responses associated with autoimmunity or allergy. In addition to confirming the importance of the CD40/CD40L interaction of T and B cells in vivo, it is established in this work that the mouse erythrocyte-specific humoral immune response of the lymphocytes in the human PBL/SCID mouse model is a bona fide T cell-dependent response, and that this is a viable model with which to study human lymphocyte activation in vivo. These results also suggest that the costimulatory activation of human B and T cells is not dependent on the microenvironment of the germinal centers.

Animals↗
PubMed1995

Adolescent food choice criteria: role of weight and dieting status.

The purpose of this study was to examine the relation of weight status, dieting status and several associated variables to the criteria for everyday food choice used by adolescents. Study participants were 411 students between the ages of 11 and 18, drawn from 15 schools. The adolescents rated 20 food in terms of nine food attributes (how tasty or healthful specific foods were, whether the foods were eaten by friends, and so forth). Within-person correlation coefficients were then calculated between these ratings and actual food choices as measured by a food frequency scale. The relation of weight and dieting status, as predictors of each of these correlational indices of the importance of potential food choice criteria, was then analysed using hierarchical multiple regression. In similar fashion, the relation was examined between weight and dieting status and: evaluations of food attributes (choice criteria); dietary quality; calorie, sugar and fat intake; body image; and physical activity. For a majority of food choice criteria and other variables, there was an apparent influence of weight as an independent variable. However, when dieting status was analysed simultaneously with weight, similar and stronger effects were now seen for dieting status and the effects of weight disappeared. Although some of the differences as a function of dieting status resembled differences shown previously in relation to dietary restraint, it is noteworthy that the simpler dieting variable yielded these associations. Overall, a "psychology of dieting" seems more relevant than "psychology of being fat versus being thin". This psychology appears to involve cognitive self-regulation processes. It is thus crucial that intervention programs and research studies take into account both the dieting status and the weight status of participants.

Adolescent↗
PubMed1995

AIDS prevention for African-American and Latina women: building culturally and gender-appropriate intervention.

African-American and Latino women are at high risk of HIV infection through heterosexual transmission, reflected in the significant increases in reported AIDS cases of women thus infected. Few AIDS-prevention programs have addressed this risk for women by directly, separately and, in appropriate ways, focusing on specific women's issues of gender roles, sexuality, and differential power relationships with men, in the context of racial and class relations, as these affect HIV transmission. This article discusses the contributions of a community-based AIDS-prevention program to the development of culturally and gender-appropriate intervention for African-American and Latina women at high risk. Further such programs are needed which build on the use of ethnic cultural concepts, racial and other social relations, and acknowledge issues specific to minority women in order to prevent their infection with HIV.

Acquired Immunodeficiency Syndrome↗