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Biomedical subjects

A C Carter

Publications and source records attributed to A C Carter.

At least 19 recordsLinked to original sources
PubMed2002

Aspect-ratio scaling and the stiffness exponent theta for Ising spin glasses.

We introduce the technique of aspect-ratio scaling to study the scale dependence of interfacial energies in Ising spin glasses, and we show how one can use it to determine the stiffness exponent theta in a clean way, with results that are independent of the domain-wall-forcing boundary conditions imposed on the system. In space dimension d = 2 we obtain theta = -0.282(3) for a Gaussian distribution of exchange interactions.

Journal Article↗
PubMed2000

Serial interleukin 6 measurements in the early diagnosis of neonatal sepsis.

The objective of the present study was to evaluate serial interleukin 6 (IL6) levels in the early diagnosis of neonatal sepsis. Subjects included 255 neonates from the Neonatal Unit of Johannesburg Hospital evaluated for suspected sepsis between February and May 1998. All infants had IL6, full blood count (FBC), C reactive protein (CRP) and blood cultures done at presentation. CRP and IL6 were repeated after 24 h. Infants were categorized into groups according to the likelihood of infection on the basis of clinical presentation, CRP, FBC and culture results, i.e., group 1 (no infection) to group 4 (definite infection). IL6 was compared between the groups by the U-test of Mann-Whitney; stepwise logistic regression was done to establish the best predictors of infection, sensitivity, specificity, positive and negative predictive values were determined. The initial IL6 level was significantly raised in those infants with possible infection [880.67 pg/ml (2966.04), p value 0.0104], probable infection [422.62pg/ml (4077.7), p value 0.0021] and definite infection [11164.39pg/ml (24139.77), p value 0.0000] as compared to those infants without infection [58.65 (182.4)]. The best predictors of infection were the combination of the initial IL6 value and CRP value after 24 h (goodness of fit 97.7 per cent). An initial IL6 value below 20 pg/ml gave a negative predictive value of 90.18 per cent. It is concluded that an IL6 value done at the time of presentation of signs and symptoms suggestive of infection is useful in the early diagnosis of neonatal sepsis. In particular, an initial IL6 value below 20 pg/ml may allow antibiotics to be withheld in a number of infants evaluated for sepsis. There is no benefit in serial determination of IL6 in the diagnosis of neonatal sepsis.

Biomarkers↗
PubMed1999

Determinants of participation in an epidemiological study of preterm delivery.

We describe the study design and patterns of participation for a cohort study of preterm delivery, focused on genital tract infections, nutrition, tobacco use, illicit drugs and psychosocial stress. Women are recruited at 24-29 weeks' gestation from prenatal clinics at a teaching hospital and a county health department. We recruited 57% of the first 1843 eligible women; 29% refused and 8% could not be contacted. White women were somewhat more likely to participate than African-American women (61% vs. 54% respectively). More notable differences were found comparing teaching hospital and health department clinics (71% vs. 47% participation respectively), with the health department clinic having a greater proportion refuse (24% vs. 33%) and more women who could not be contacted (4% vs. 11%). Participation was affected only minimally by day or timing of recruitment, but inability to contact diminished substantially as the study continued (13-0%). Refusals were largely unrelated to patient attributes. Lower education predicted inability to contact. Risk of preterm delivery was 14% among recruited women, 10% among women who refused, and 15% among women whom we were not able to contact, demonstrating that, overall, risk status was not lower among recruited women.

Adolescent↗
PubMed1996

A standard protocol for the evaluation of laser treatment of the prostate. The British Laser Urological Evaluation Society (BLUES)

OBJECTIVES: To present a standardized protocol, suitable for general use, for the evaluation of laser treatment of the prostate. METHODS: Many new operative treatments which are available to treat symptomatic prostatic enlargement are being accepted and offered to patients after scanty clinical evaluation, e.g. interventions using lasers. A consistent and standard protocol was developed, comprising data-recording sheets for patients' admission details, pre-operative assessments, operative details of laser ablation, post-operative in-patient progress and re-attendance, and subsequent out-patient follow-up. RESULTS: The protocol was tested by the members of BLUES and fulfilled their requirement for easy use in any department of Urology. It provides a simple way of accurately recording relevant data within a structured format with the additional advantage of permitting results to be expressed uniformly. CONCLUSION: The adoption of this protocol will allow valid comparisons of core data between studies assessing different procedures. The flexibility of the protocol enables it to be used, with minor modification, for the evaluation of any operative intervention aimed at relieving prostatic symptoms.

Clinical Protocols↗
PubMed1996

Accuracy of video imaging in mandibular surgery.

Video imaging can simulate combined orthodontic-orthognathic surgical treatment to assist in treatment planning and patient education. Video imaging predictions were compared with actual posttreatment results for 18 patients who received orthodontic and mandibular orthognathic surgical treatments. Three untreated control subjects were also studied. The locations of 13 soft tissue landmarks relative to horizontal and vertical reference planes were compared between predictions and posttreatment photographs, and significant variation (+/- 5 mm) was found for many of the landmarks. Comparisons of various steps repeated during the prediction process were also completed to test for reproducibility. Relatively small differences, generally less than +/- 2 mm, were attributed to the process of linking the cephalogram and photograph and to the manual steps to create surgical treatment objectives. The largest proportion of the total variation, about 80%, was estimated to arise from inaccuracy inherent in the software program. Other contributions to the total variation likely came from physiologic facial changes over time and nonstandardized head positions in the photographs.

Adolescent↗
PubMed1994

Estrogen receptor immunocytochemistry: the promise and the perils.

Estrogen receptor immunocytochemistry (ERICA) is favored over dextran-coated charcoal (DCC) or sucrose gradient assay (SGA) by many pathologists and oncologists since it allows an estimation of tumor cell and tissue heterogeneity and permits assays to be performed on specimens not suitable for DCC/SGA. Additionally, ERICA can be performed with greater ease and with less expense at the level of the community hospital pathology laboratory. Initially, like DCC/SGA, ERICA had to be done on fresh or frozen tumor samples or face a significant loss in sensitivity when applied to formalin-fixed, paraffin-embedded sections. Recently, several anti-estrogen receptor (ER) antibodies have appeared which can be successfully employed to assay routinely prepared tissue sections if used in conjunction with new antigen-retrieval techniques such as the microwave oven and citrate buffers. However, more work is needed to correlate results of these new procedures with biochemical ER assays, endocrine response, and survival before they can be reliably employed as prognostic parameters. Furthermore, if any ER assay is to be useful and valid, strict attention must be paid to details of specimen collection, freezing, and fixation in order to inhibit receptor degradation and false negative results.

Breast Neoplasms↗
PubMed1993

Steroid hormone receptor immunohistochemistry and amplification of c-myc protooncogene. Relationship to disease-free survival in breast cancer.

BACKGROUND: It is important to develop parameters that aid in prognosticating which patients with breast cancer are more likely to have a rapid disease course and therefore might benefit from early aggressive therapies. METHODS: Specimens from two groups of women, deliberately selected because their clinical courses differed greatly, were studied to detect amplification of the protooncogenes c-myc, int-2, and C-erbB-2/neu by slot-blot assay, the estrogen receptor (ER), and the progesterone receptor (PR) by both biochemical and immunohistochemical procedures (ERICA and PRICA). One group of 50 patients had a prolonged disease-free interval after initial surgery (mean, 6.4 years); the other group of 52 women had had rapid disease recurrence (mean, 1.4 years) or progression (5 patients died of disease within 1 year of diagnosis). The patients were selected from 1700 consecutively accessioned cases if they fit the study criteria and sufficient tissue was available for oncogene hybridization studies. RESULTS: The two groups differed statistically by stage, number of involved axillary lymph nodes, ERICA and PRICA results (P = 0.001), and amplification of c-myc (P = 0.003). The percentage of patients with rapid disease recurrence and progression increased from 0-93% when risk factors changed from best case (ERICA and PRICA results, positive; c-myc, not amplified; and axillary nodes, not involved) to worst case (ERICA and PRICA findings, negative; c-myc, amplified; and axillary nodes, involved). CONCLUSIONS: Women with these worst-case parameters were more likely to have a recurrence sooner and rapidly progressive disease. They might benefit from early aggressive therapeutic measures.

Adult↗
PubMed1990

Immunocytochemical estrogen and progestin receptor assays in breast cancer with monoclonal antibodies. Histopathologic, demographic, and biochemical correlations and relationship to endocrine response and survival.

Breast cancer specimens from 600 women were assayed for estrogen receptors (ER) using an immunocytochemical assay (ICA) employing the monoclonal antiestrophilin antibody H222 Sp gamma. Results showed significant correlation with biochemical ER determinations as well as with tumor grade and menopausal status. In 449 cases, results of progesterone receptor assay by ICA using the monoclonal anti-PgR antibody KD 68, also correlated significantly with biochemical PgR measurements. The ERICA/PgRICA positivity was significantly more frequent in postmenopausal white women. Colloid carcinomas were most likely to be ERICA positive and PgRICA positive whereas medullary carcinomas were most often negative. In 47 patients with advanced mammary carcinoma, results of ERICA and PgRICA were more closely related to endocrine response than those of ER and PgR by dextran-coated charcoal assay (DCC). In 339 women with Stage I or Stage II breast cancer, ERICA was significantly associated with disease-free survival. Analysis by Cox's proportional hazard model, however, showed PgRICA to be the best predictor of survival and disease-free survival in 197 women at the same stages of disease. These data indicate that ICA is more predictive of prognosis than biochemical ER and PgR. The ease of ICA performance coupled with these results indicate that the method is an acceptable substitute for DCC in analyzing breast cancers for ER/PgR.

Adult↗
PubMed1990

Effect of age on the in vitro reflection coefficient of the aortoiliac bifurcation in humans.

The local reflection coefficient (r) at the aortoiliac junction was estimated in vessels removed at autopsy from 15 females and 31 males aged 2 months to 88 years by calculating the characteristic impedance (Zc) of the abdominal aorta and the two common iliac arteries. Zc was evaluated for each vessel by measuring cross-sectional area from radiographs and propagation velocity of an isolated pressure impulse generated by a solenoid-driven piston connected to the distal end of the abdominal aorta, and detected at several sites a known distance from the junction. Attenuation coefficients in the aorta were estimated from the peak amplitude of the impulse at these several sites. We observed significant decreases with age in abdominal aortic attenuation coefficient (gamma = 0.053-5 x 10(-4) age [yr], r = -0.42, p less than 0.005), and the area ratio (AR) of the junction (sum of the iliac cross-sectional areas/aortic cross-sectional area) (AR = 0.93-0.002 x age [yr], r = -0.31, p less than 0.05). Bifurcation angle (Angle) and aortic propagation velocity (caorta) increased significantly (angle = 40.2 + 0.26 x age [yr], r = 0.41, p less than 0.01; caorta (ms-1) = 7.59 + 0.175 x age [yr], r = 0.69, p less than 0.0001). No significant association between age and iliac propagation velocity was found. On the basis of area measurements alone, it has been argued that the observed decrease in area ratio with age causes r to become more positive. The lack of age-related changes in iliac propagation velocity (and hence stiffness), an observation confirmed by most of the few reports in the literature, and the large increase in abdominal aortic stiffness, however, greatly outweighed the area ratio changes and caused a significant decline in reflection coefficient from +0.3 in early life to -0.3 in old age. (Reflection coefficient = 0.30-0.0065 x age [yr], r = -0.68, p less than 0.0001). Between the ages of 30 and 60 years, its absolute value was less than 0.1, confirming in vivo work on subjects within this age range. In children, a significant positive reflection at the distal end of the aorta will amplify the pulse wave in this region. As this vessel becomes stiffer with increasing age, amplification will increase, whereas the increasingly negative value of r will partially offset this rise, reducing pulse pressure on either side of the junction.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1988

Immunocytochemical detection of progesterone receptor in breast cancer with monoclonal antibody. Relation to biochemical assay, disease-free survival, and clinical endocrine response.

A new immunocytochemical assay for progesterone receptor (PgR-ICA) employing the monoclonal antibody JZB 39 was used to study tumors from two series of patients with breast cancer. In Series 1 assay results were in agreement with those of biochemistry in 76% of 338 cases (P less than 0.001) and in 54% of 101 cases in Series 2 (P less than 0.001). Agreement was better in Series 1 because it included fresher, previously untouched specimens. There were 70 patients in Series 1 with known clinical endocrine response. A negative assay correlated with disease progression in 45 of 57 patients, significantly better than with biochemistry (P = 0.013). In comparing 39 women with rapid disease progression with 39 free of disease at 5.1 years, those with PgR-ICA-positive tumors were over four times more likely to remain disease-free than those with negative results (P = 0.007). Product moment life-table analysis of 79 patients from Series 2 showed a significantly better cumulative survival for those with PgR-ICA-positive tumors (P = 0.047). These findings indicate that PgR-ICA should be of value in planning therapy and predicting disease course in breast cancer patients.

Antibodies, Monoclonal↗
PubMed1986

Histochemical estrogen binding. An independent predictor of recurrence and survival in stage II breast cancer.

Cox's proportional hazards regression model was used to analyze the prognostic significance of multiple variables affecting recurrence and survival in patients with Stage II breast cancer. Among the variables were biochemical estrogen (ER) and progesterone receptor (PgR) values and results of a histochemical estrogen-binding assay using a fluoresceinated bovine serum albumin-estradiol conjugate where carrier and label were bound at position 17. In 190 cases ER and PgR were not found to be significantly associated with either disease recurrence or patient survival. On the other hand, patients with tumors that were demonstrably "rich" in estradiol ligand conjugate binding by histochemistry experienced both a longer disease-free interval (P less than 0.03) and survival (P less than 0.02) than did patients whose tumors were "poor" in conjugate binding or showed a heterogeneous population of positively and negatively stained cells. A patient with a tumor rich in estrogen binding was five times more likely to survive than a patient with a neoplasm that was poor in estrogen binding by histochemistry. These results indicate that the histochemical technique used provides new and independent parameters for determination of prognosis in Stage II breast cancer.

Adult↗
PubMed1985

Immunohistologic localization of estrogen receptors in breast cancer with monoclonal antibodies. Correlation with biochemistry and clinical endocrine response.

Breast cancer specimens from 114 patients were assayed for the presence of estrogen receptors (ER) utilizing highly specific, monoclonal antiestrophilin antibodies and the peroxidase-antiperoxidase technique. Results were compared with conventional ER determinations by the dextran-coated charcoal method (DCC) and were in agreement as to positivity and negativity in 86%. Semiquantified immunocytologic assay results were in accord with the level of ER as measured by DCC in 66%. The tumors studied included 43 from patients with Stage IV disease where clinical response to hormonal manipulation was known. In the latter group, the immunohistologic method had a sensitivity similar to that of DCC but showed a superior positive predictive value and a significantly better specificity. These results indicate that this new method is a valuable laboratory tool, enabling prediction of hormone responsiveness in advanced mammary carcinoma and capable of performance at the community hospital level.

Antibodies, Monoclonal↗
PubMed1985

Heterogeneity of estrogen binding sites in breast cancer: morphologic demonstration and relationship to endocrine response.

Breast cancer specimens from 184 patients were analyzed for estrogen binding by two different histochemical techniques using conjugates of estradiol, bovine serum albumin, and fluorescein. In one conjugate estradiol was bound at position 6, in the other at position 17. Results were in agreement in 64% (p less than .001), but obvious differences in ligand distribution were noted. Results were also correlated with estrogen receptor (ER) analysis by dextran-coated charcoal assay (DCC) and were in accord in 65% and 67% of specimens respectively (p less than .001). In 114 cases, the tissue samples were also studied with the estrogen receptor immunocytochemical assay (ERICA) of Greene and his colleagues, which employs monoclonal antibodies to ER protein. Results were in accord with DCC in 86% (p less than .001). The pattern of staining with ERICA differed from that of either histochemical method. In 43 cases assay results were correlated with clinical endocrine response. Overall, the best statistical prognostic parameters were obtained with ERICA. Analysis of combined assay results revealed that patients with assays positive by all techniques were the most likely to respond to hormonal treatment (p less than .001), whereas if one or more assays were negative the chances for a good response were significantly less favorable. These data suggest that DCC and ERICA are both a measure of the same estrogen binding site (type I) while the histochemical methods apparently identify two other separate and distinct sites (putative type II sites). A degree of positive interaction may exist between these multiple estrogen binding sites.

Binding Sites↗
PubMed1985

An evaluation of the effect of vincristine added to cyclophosphamide, 5-fluorouracil, methotrexate, and prednisone in advanced breast cancer.

A multi-institutional randomized clinical trial was carried out to evaluate the effect of vincristine (V) added to cyclophosphamide, methotrexate, 5-fluorouracil, and prednisone (CMFP) for the treatment of metastatic breast cancer. There were 427 patients entered into the study and randomly assigned to one of the two treatments, i.e. the five drug therapy CMFPV or the four drug therapy CMFP. The differences in patient survival and tumor response between the two treatment groups were not statistically significant. The data were also analyzed using multivariate procedures to determine those factors ascertained at entry into the study which were predictors of survival or predictors of response to therapy. The one factor that predicted both response and survival was performance status. An additional important predictor of survival was sites of metastatic involvement. Other significant predictors of response were menopausal age, BUN, and hematocrit.

Adult↗
PubMed1985

Methods of motivating the practice of breast self-examination: a randomized trial.

A randomized trial of 1,733 women compared three methods of motivating the practice of breast self-examination (BSE): (a) cognitive teaching which emphasized factual knowledge; (b) affective teaching which stressed feelings, attitudes, and values; and (c) a mixed approach which combined features of both. Subjects returned for follow-up at 3, 12, and 24 months or at 6 and 12 months, at which times they completed questionnaires and were evaluated by nurses. They demonstrated how they performed BSE and palpated breast models for lumps. No differences were observed among the teaching groups for any of several indicators of BSE practice, such as frequency, knowledge about when to do BSE, technique, or number of lumps detected in the model. However, these measures were associated with women's initial confidence in practicing BSE. Women in all teaching groups improved their BSE technique over time. Women in this study practiced BSE more frequently and detected more lumps than reported in other studies. The better performance of subjects in the present study might be ascribed to the amount of time spent teaching and to reinforcement from repeated follow-ups. The affective and cognitive approaches were equally effective in motivating the practice of BSE.

Adult↗
PubMed1984

Characteristics of a specific radioimmunoassay for measurement of ferritin on the surface of peripheral mononuclear white blood cells in cancer patients.

Using 125I-labeled rabbit anti-Hodgkin's spleen ferritin antibody (RHF), a simple radioimmunoassay has been developed for quantitation of ferritin on the surface of peripheral blood mononuclear white blood cells (PBM). This method makes use of a % specific binding determination (%SP) by measuring the amount of 125I-labeled RHF bound to 1 X 10(6) PBM in the presence and absence of soluble ferritin. To standardize this procedure, artificial ferritin positive control cells were prepared by covalently coupling ferritin to cultured acute lymphoblastic leukemia cells. These cells were tested on a daily basis in parallel with patient PBM's to ensure inter and intra-assay precision and remained stable for over two years. Characteristics of 125I-labeled RHF binding to control and patient PBM's were evaluated to determine the specificity of interaction and optimum binding parameters. %SP was linear in the range of 1 X 10(5) - 1 X 10(6) PBM's and was progressively inhibited by graded concentrations of soluble ferritin. F(ab')2 preparations of RHF were equally as effective as intact RHF in blocking 125I-labeled RHF binding confirming that 125I-labeled RHF was not binding non-specifically to PBM Fc receptors. Additional experiments describing kinetics and methods of standardization of new lots of 125I-labeled RHF are also described.

Cell Membrane↗
PubMed1984

Measurement of ferritin-bearing peripheral mononuclear blood cells in cancer patients by radioimmunoassay.

A radioimmunoassay has been developed to measure ferritin bound to the surface of isolated human peripheral blood mononuclear white blood cells (PBMs) in order to investigate the possible relationship of this phenomenon to breast and other forms of cancer. The assay measures the specific binding (%SP) of affinity-purified 125I-labeled rabbit anti-Hodgkin's spleen ferritin antibody to isolated patient PBMs. A preliminary prospective, preclinical trial on 300 patients was run which included: (a) normals, benign breast disease, and medical/surgical patients as non-cancer controls; (b) postoperative primary cancer and advanced cancer in clinical remission as post cancer controls; and (c) both early preoperative breast cancer patients and cancer patients with localized recurrences or active disseminated disease as test groups. The mean %SP for the non-cancer control groups was in the range of 4.3 to 5.1 (n = 187), which was identical to that for inactive cancer or postoperative cancer, which was no evidence of recurrence. Using a %SP normal cutoff level of 6.5, which resulted in a false-positive rate of approximately 10% for both non-cancer and post-cancer control groups, only 27% of early preoperative cancers (n = 22) gave elevated %SP values. These results suggest that measurement of ferritin-PBM is inappropriate for early disease diagnosis. In contrast, 91% of patients with advanced active breast cancer and 73% of those patients with other types of advanced cancers, including tumors of ovarian, lung, colon or esophageal origin, showed elevated %SP values more than double those of post-cancer controls. The mean %SP value in active advanced cancer was 10.8 for breast (n = 12) and 10.6 for all other solid tumors investigated (n = 34). Paired patient comparisons of ferritin-PBM and plasma carcinoembryonic antigen in breast cancer showed elevations in 91% of the patients for ferritin-PBM and 67% for carcinoembryonic antigen. Overall, these results suggest that patients with advanced cancer display elevated levels of ferritin on the surface of their PBMs and that this measurement may be a useful adjunct in monitoring and evaluating the clinical status of cancer patients.

Breast Diseases↗