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Biomedical subjects

S Lele

Publications and source records attributed to S Lele.

17 recordsLinked to original sources
PubMed2000

Prospective audit following the introduction of short-course preoperative radiotherapy for rectal cancer.

BACKGROUND: The value of introducing a short course of preoperative radiotherapy before operation for rectal cancer is still subject to debate. METHODS: One hundred consecutive patients, of mean age 68 (range 29-87) years undergoing pre- operative radiotherapy for rectal cancer between January 1997 and December 1998 at two radiotherapy centres were audited prospectively. RESULTS: The time from referral to radiotherapy was 33 (11-74) days and from radiotherapy to operation 5 (1-42) days. There was a higher than expected anastomotic leak rate (15 per cent) and perineal wound infection rate (18 per cent). Patients waiting more than 7 days were more likely to suffer perineal wound breakdown: 15 per cent (n = 39) versus 30 per cent (n = 10). CONCLUSION: The high anastomotic leak and perineal wound infection rates suggest that the introduction of preoperative radiotherapy combined with total mesorectal excision should be audited carefully or performed as part of the CRO7 trial. Presented to the Association of Coloproctology of Great Britain and Ireland in St Helier, Jersey, June 1998

Adult↗
PubMed1998

Capturing data from three-dimensional surfaces using fuzzy landmarks.

Anatomical landmarks are defined as biologically meaningful loci that can be unambiguously defined and repeatedly located with a high degree of accuracy and precision. The neurocranial surface is characteristically void of such loci. We define a new class of landmarks, termed fuzzy landmarks, that will allow us to represent the form of the neurocranium. A fuzzy landmark represents the position of a biological structure that is precisely delineated, but occupies an area that is larger than a single point in the observer's reference system. In this study, we present a test case in which the cranial bosses are evaluated as fuzzy landmarks. Five fuzzy landmarks (the cranial bosses) and three traditional landmarks were placed repeatedly by a single observer on three-dimensional (3D) computed tomography (CT) surface reconstructions of pediatric dry skulls and skulls of pediatric patients, and directly on four of the same dry skulls using a 3Space digitizer. Thirty landmark digitizing trials from CT scans show an average error of 1.15 mm local to each fuzzy landmark, while the average error for the last ten trials was 0.75 mm, suggesting a learning curve. Data collected with the 3Space digitizer was comparable. Measurement error of fuzzy landmarks is larger than that of traditional landmarks, but is acceptable, especially since fuzzy landmarks allow inclusion of areas that would otherwise go unsampled. The information obtained is valuable in growth studies, clinical evaluation, and volume measurements. Our method of fuzzy landmarking is not limited to cranial bosses, and can be applied to any other anatomical features with fuzzy boundaries.

Child↗
PubMed1998

Predicting key malaria transmission factors, biting and entomological inoculation rates, using modelled soil moisture in Kenya.

While malaria transmission varies seasonally, large inter-annual heterogeneity of malaria incidence occurs. Variability in entomological parameters, biting rates and entomological inoculation rates (EIR) have been strongly associated with attack rates in children. The goal of this study was to assess the weather's impact on weekly biting and EIR in the endemic area of Kisian, Kenya. Entomological data collected by the U.S. Army from March 1986 through June 1988 at Kisian, Kenya was analysed with concurrent weather data from nearby Kisumu airport. A soil moisture model of surface-water availability was used to combine multiple weather parameters with landcover and soil features to improve disease prediction. Modelling soil moisture substantially improved prediction of biting rates compared to rainfall; soil moisture lagged two weeks explained up to 45% of An. gambiae biting variability, compared to 8% for raw precipitation. For An. funestus, soil moisture explained 32% variability, peaking after a 4-week lag. The interspecies difference in response to soil moisture was significant (P < 0.00001). A satellite normalized differential vegetation index (NDVI) of the study site yielded a similar correlation (r = 0.42 An. gambiae). Modelled soil moisture accounted for up to 56% variability of An. gambiae EIR, peaking at a lag of six weeks. The relationship between temperature and An. gambiae biting rates was less robust; maximum temperature r2 = -0.20, and minimum temperature r2 = 0.12 after lagging one week. Benefits of hydrological modelling are compared to raw weather parameters and to satellite NDVI. These findings can improve both current malaria risk assessments and those based on El Niño forecasts or global climate change model projections.

Animals↗
PubMed1995

Euclidean distance matrix analysis: confidence intervals for form and growth differences.

Analysis of biological forms using landmark data has received substantial attention recently. Much of the statistical work in this area has concentrated on the estimation of average form, average form difference, and average growth difference. From the statistical, as well as the scientific point of view, it is important that any estimate of a scientifically relevant quantity be accompanied by a statement regarding its accuracy. Such a statement is contained in a confidence interval. The purpose of this paper is to provide a method to obtain confidence intervals for form difference and growth difference estimators. The estimators are based on Euclidean distance matrix analysis. The confidence intervals are calculated using the model independent bootstrap method. We illustrate the method by using three examples: morphological differences between samples of craniofacial patients and normal controls using two dimensional data from head X-rays, sexual dimorphism of craniofacial morphology in Cebus apella, and sexual dimorphism of facial growth in Cebus apella using three-dimensional data.

Animals↗
PubMed1994

Basic fibroblast growth factor and receptor expression in human ovarian cancer.

Basic fibroblast growth factor (bFGF) and other members of the FGF family share several biological properties that have the potential to mediate neoplastic cell growth. To test the hypothesis that bFGF may play a role in human ovarian cancer cell growth, three ovarian cancer cell lines, A90, A121(P), and A121(A), were investigated for their ability to respond to bFGF as a mitogen, to express endogenous bFGF protein or message for FGF proteins, and to exhibit FGF receptor or its message. Addition of bFGF to cultures of all three cell lines maintained in chemically defined media resulted in a statistically significant increase in cell number. Cell extracts from A90, A121(P), and A121(A) contained an immunoreactive protein that comigrated with hr-bFGF by Western blot analysis. Several bands of higher molecular weight were also noted. Immunohistochemical staining for bFGF demonstrated a cytoplasmic distribution of bFGF in the three cell lines. Both high- and low-affinity binding sites for human recombinant bFGF (hr-bFGF) were expressed by all three lines. High-affinity sites varied from 2700 sites per cell (Kd = 29 pM) to 13,500 sites per cell (Kd = 71 pM). All three cell lines were screened for mRNA expression for seven FGF proteins and four FGF receptors. In all three lines, mRNA for FGF2 (bFGF) was detected by PCR analysis, and in two lines, mRNA for FGF1 (aFGF) and FGF5 were also found. The FGFR1 receptor subtype (flg) was common to all of the cell lines. Finally, suramin inhibited proliferation of A90 and A121 (P and A) with IC50's of 60 and 210 micrograms/ml, respectively. This is consistent with the A90 cell line having higher levels of endogenous bFGF and flg and therefore being more responsive to suramin inhibition than the A121 cell line. The results indicate that these ovarian cancer cell lines can produce bFGF as well as other members of the FGF family of genes and have the ability to respond to bFGF.

Base Sequence↗
PubMed1993

A coordinate-free approach to the analysis of growth patterns: models and theoretical considerations.

Developmental biology holds keys to our understanding of morphological pattern formation whether these patterns are expressed in the fossil record or among extant species. Though much is known about osseous growth at the cellular level (e.g. Hall, 1991), we have minimal understanding of the coordinated processes that combine to produce a complex, three-dimensional form. We have proposed a framework for the coordinate-free representation of form, a statistical method for comparing and modelling growth trajectories for complex morphologies, and a means for the eventual elucidation of the role of growth in the evolution of morphology. Our method uses the coordinate locations of biological landmarks to represent form as a matrix of all possible linear distances between landmarks, the form matrix. When two forms are expressed in this way, comparison of these forms is accomplished by computing the ratios of like linear distances, the form difference matrix. When the forms being compared are from a growth series, the matrix of ratios is called a growth matrix. Patterns of growth for two groups can be compared by computing the growth difference matrix. We applied growth difference matrix analysis to the study of sexual dimorphism of ontogeny in the M. fascicularis craniofacial skeleton. Growth matrices describing growth in male and female M. fascicularis were presented along with the growth difference matrix that describes sexual dimorphism of growth to underscore the detailed information available from this analytical technique. The method is quite general and can be applied to two- or three-dimensional data sets of landmark coordinates (cross-sectional or longitudinal) collected from almost any developing structure. The methods that we propose enable us to go beyond a mathematical summary of the comparison of forms and the comparison of growth patterns. We provide examples of how growth patterns might be used in the study of phylogenetic relationships. Our plans for use of this method in the study of evolutionary change assumes that morphological change in the craniofacial skeleton results from evolutionary change in developmental units (as defined by Atchley & Hall, 1991) that underlie morphological structure. We believe we have the basic tools to ultimately propose informed phylogenies based solely on developmental data. This task requires the identification of 'growth features' and the polarization of these features as primitive or derived. It is also advisable to determine a set of primitive growth features for the groups of interest. This will necessitate the inclusion of outgroups in our growth analysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

On comparing biological shapes: detection of influential landmarks.

For problems of classification and comparison in biological research, the primary focus is on the similarity of forms. A biological form consists of size and shape. Several approaches for comparing biological forms using landmark data are available. If the two biological forms are demonstrated to be different, the next important issue is to localize the differences by identifying those areas which differ most between the two objects. In this paper we suggest a technique to detect influential landmarks, those which contribute most to the difference between forms. We study the effectiveness of the technique using three-dimensional simulated data sets and two examples. Results suggest that the technique is useful in the study of biological form and its variation.

Acrocephalosyndactylia↗
PubMed1992

A laboratory evaluation of the Kowa laser flare-cell meter for the study of uveitis.

The Kowa FC-1000 laser flare-cell meter (LFCM) has been described as an instrument which will objectively quantify inflammation of the anterior chamber of the eye. We evaluated the LFCM using the intravenous endotoxin-induced uveitis (EIU) rabbit model of ocular inflammation. In vitro flare and cell calibration measurements utilizing bovine serum albumin (BSA) and latex particles, respectively, were also performed. A linear relationship between the flare measurements and BSA concentrations was noted. In addition, the time course of the LFCM flare count in EIU was comparable to previously published fluorophotometric data. However, the LFCM reported cells in the anterior chamber of the EIU rabbits despite negative cytology and histology results. The LFCM also recorded cells in BSA solutions which contained neither cells nor latex particles. Our results suggest that although the LFCM may be useful for evaluating flare, its cell measurements are not accurate in cases of severe uveitis.

Animals↗
PubMed1991

Some comments on coordinate-free and scale-invariant methods in morphometrics.

The unusual strategy for comparing biological shapes is to use some kind of superimposition of the two forms under study and then look at the "residuals" as the shape change. In this paper, I take a careful look at this general strategy and point out some subtle but inherent and important pitfalls. Additionally an alternative approach based on Euclidean Distance Matrix representation is presented. It is applicable to two- as well as three-dimensional objects.

Anatomy↗
PubMed1991

Euclidean distance matrix analysis: a coordinate-free approach for comparing biological shapes using landmark data.

For problems of classification and comparison in biological research, the primary focus is on the similarity of forms. A biological form can be conveniently defined as consisting of size and shape. Several approaches for comparing biological shapes using landmark data are available. Lele (1991a) critically discusses these approaches and proposes a new method based on the Euclidean distance matrix representation of the form of an object. The purpose of this paper is to extend this new methodology to the comparison of groups of objects. We develop the statistical versions of various concepts introduced by Lele (1991a) and use them for developing statistical procedures for testing the hypothesis of shape difference between biological forms. We illustrate the use of this method by studying morphological differences between normal children and those affected with Crouzon and Apert syndromes and craniofacial sexual dimorphism in Cebus apella.

Acrocephalosyndactylia↗
PubMed1990

Analysis of craniofacial growth in Crouzon syndrome using landmark data.

Finite-element scaling analysis (FESA), generalized procrustes analysis (GPA), and Euclidean distance matrix analysis (EDMA) are applied in a two-dimensional study of craniofacial growth in normal children and those affected with Crouzon syndrome. Longitudinal data are used and growth is measured as change local to 10 craniofacial landmarks. Although details of the results vary among the methods, all 3 methods determine Crouzon growth to be different from normal. Nuances of the methods, especially the use of superimposition in GPA and lack of superimposition in 2 others are partly responsible for the varying results. Although Crouzon craniofacial morphology is often obvious at birth, this study demonstrates that there are general differences between normal postnatal growth patterns and those of the Crouzon individual. These patterns of malgrowth are in part responsible for the adult morphology of the Crouzon craniofacial complex.

Adolescent↗
PubMed1980

Weekly cis-diamminedichloroplatinum(II): active third-line chemotherapy in ovarian carcinoma--a preliminary report.

Ten evaluable patients with progressive ovarian adenocarcinoma received third-line chemotherapy consisting of weekly cisplatin (cis-diamminedichloroplatinum[II]) at a dose of 1 mg/kg weekly for a maximum of 6 weeks followed by 60 mg/m2 every 3 weeks. There was no life-threatening toxicity. Seven patients (70%) achieved an objective partial response. This is the highest response rate achieved, to date, by third-line chemotherapy in women with advanced ovarian adenocarcinoma. Weekly cisplatin therefore warrants a trial as first-line therapy.

Adenocarcinoma↗
PubMed1980

Melphalan, 5-fluorouracil, and medroxyprogesterone acetate in metastatic or recurrent endometrial carcinoma. Preliminary report.

The purpose of this study was to evaluate therapy with melphalan, 5-fluorouracil (5-FU), and medroxyprogesterone acetate combination (MFP) in women with metastatic or recurrent endometrial carcinoma not amenable to surgery or radiation therapy, as compared to progesterone therapy alone. Previously, the authors have treated 114 women with progesterone therapy and achieved a 15.8% objective response rate; 7.0% were complete responders. Thirteen women with documented recurrent or metastatic endometrial carcinoma were entered into the MFP study. Thirteen were evaluable for toxicity and 11 for response (2 had no measureable parameter). Treatment consisted of melphalan 0.2 mg/kg/day for 4 days every 4 weeks; 5-FU 15 mg/kg/day for 4 days every 4 weeks; and medroxyprogesterone acetate 1.0 g intramuscularly weekly. Two of the first 3 patients who were treated with this regimen developed severe thrombocytopenia (platelets, 25,000 and 17,000/mm3). Therefore, the remaining 10 patients received 5-FU at a dose of 10 mg/kg/day for 4 days every 4 weeks. Except for 1 patient who devloped thrombophlebitis, there was no other significant toxicity in the 90 courses of therapy received by the 13 women. Of the 11 women evaluable for respone, 6 (54.5%) responded (2 complete responders, 4 partial responders), 2 for stationary disease, and 3 progressed after having had stationary disease for 3, 6, and 9 months, respectively. Of special interest was that the 2 women with adenosquamous carcinoma responded and 1 additional patient with adenocarcinoma maintained a complete response with 5-FU therapy alone.

Adenocarcinoma↗
PubMed1976

Enterovaginal and enterocutaneous fistulae in women with gynecologic malignancies.

From 1957 to 1975, 43 women with gynecologic malignancies had associated enterocutaneous or enterovaginal fistula. Thirty-four of these women underwent surgical correction of the fistula. The etiology, diagnostic evaluation, preoperative complications, and surgical correction of such fistulae are discussed. In addition, a staged planned management of these fistulae is outlined.

Adult↗
PubMedDate not supplied

Cyclophosphamide, hexamethylmelamine, doxorubicin, and cisplatin (CHAD) as second-line chemotherapy for ovarian adenocarcinoma.

Twenty women with recurrent ovarian adenocarcinoma received a monthly four-drug combination of cyclophosphamide, hexamethylmelamine, doxorubicin, and cisplatin as second-line chemotherapy. There were no objective responses to this regimen. This is in contrast to the 49% response rate reported by Kane et al using these four drugs and the 63% response rate reported by Vogl et al using three of these drugs as second-line chemotherapy. The differences in the three regimens are reviewed; however, we could not identify reasons sufficient to account for the disparity in response rates.

Adenocarcinoma↗
PubMedDate not supplied

Preoperative morphology and development in sagittal synostosis.

The goal of this study is to characterize the differences between normal cranial morphology and that of patients diagnosed with isolated sagittal synostosis, using three-dimensional (3D) landmark coordinate data collected from computed tomography (CT) scans. This retrospective study uses pre-operative CT images of a sample of children diagnosed with isolated sagittal synostosis (N = 23) and of dry skulls of unaffected children (N = 10). In order to be included in the study, patients had to have a confirmed diagnosis of sagittal synostosis and a pre-operative CT scan of acceptable quality available in digital format. Separation of normal and synostosed individuals on the basis of craniofacial morphology was achieved by applying a principal coordinates analysis to a dissimilarity matrix calculated from the landmark coordinate data. Direct comparison of age-graded samples of normal and synostosed individuals using Euclidean Distance Matrix Analysis enabled localization of the morphological differences between samples. This method was also used to characterize growth patterns of the two samples using cross-sectional data. The parietal bosses were found to be the features that were most influential in separating sagittal synostosis patients from their age-matched normal counterparts. A cross-sectional analysis of growth showed that the specifics of the growth differences between normal and sagittal synostosis individuals changed with the age interval considered. We present direct evidence that the parietal bosses are critical in the differentiation of normal and sagittal synostosis morphology, and indirect evidence of the possible role of the parietal tubers in the etiology of sagittal synostosis.

Child↗