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D Smith

Publications and source records attributed to D Smith.

At least 577 records · Page 32Linked to original sources
PubMed1995

Self-association of interleukin 2 bound to its receptor.

Although radioiodinated interleukin 2 (IL-2) has been used to define the binding characteristics of the cytokine to the alpha chain of the receptor complex, we have found that unsubstituted IL-2 behaves differently. Whereas previous investigations with radioiodinated IL-2 have shown binding to the alpha chain with a Kd of 10 nM, we show that unsubstituted IL-2 binds to the alpha chain but does not reach saturation between 100 and 1000 nM. The explanation for the discrepancy between the analysis of radioiodinated and unsubstituted cytokine involves the propensity of unsubstituted IL-2 for self-association, a property that is abrogated by radioiodination. The functional relevance of our findings is indicated by the different capacities of unsubstituted and iodinated cytokine to induce prolonged proliferation of human T lymphocytes.

Artifacts↗
PubMed1995

Calcification of breast implant capsules: incidence, diagnosis, and contributing factors.

From January 1990 to August 1994, more than 6000 patients with silicone-gel breast implants were clinically assessed regarding their implant status. Of these, 82 patients requested removal of their implants (150 implants). Of the 150 implants that were removed, 24 (16%) demonstrated calcified capsules. All 12 patients with calcification demonstrated this finding bilaterally. All calcified capsules demonstrated discrete calcified plaques on their inner surface. All 12 patients presented with Baker class IV contractures, with pain as their chief complaint. One patient demonstrated calcification on a routine chest radiograph. One patient demonstrated a stippled appearance on xeromammogram. Capsular calcification was related to the duration of implantation. All 6 implants that had been in place for 23 to 26 years were associated with calcification. These implants were all of the thick-walled Dacron-backed type. All thick-walled Dacron-backed implants that were removed in this study were associated with calcification. Of the 69 implants that had been inserted for 11 to 20 years, 18 (26.1%) were associated with calcification. Fifteen of these 16 implants were ruptured. None of the implants that had been in place for 10 years or less demonstrated calcification.

Breast Implants↗
PubMed1995

Do patients with silicone-gel breast implants have elevated levels of blood silicon compared with control patients?

Whole blood silicon levels in 30 patients with silicon-gel implants (inserted between 1973 and 1991) were compared with those of 24 healthy, age-matched, female patients without breast implants using atomic absorption spectrometry with a graphite furnace. The blood silicon levels in the implant patients were significantly higher than those of controls (medians 33.45 vs 17.05 ng/ml; p = 0.005). Of the 30 patients with implants, 15 had received their implants between 1973 and 1985, and 15 had received implants between 1986 and 1991. Implants made between 1973 and 1985 have been shown to be weaker and to have higher silicone "bleed" levels than those made from 1986 onward. However, there were no significant differences in the blood silicone levels between these two groups of patients.

Breast Implants↗
PubMed1995

Analysis of silicon levels in capsules of gel and saline breast implants and of penile prostheses.

Although a potential link between silicone-gel breast implants and autoimmune connective tissue disease has been suggested, none has been proven. The potential role of silicone as an immune adjuvant remains very controversial. Currently available techniques do not allow precise measurements of silicone in tissues. However, all compounds containing silicon (including silicone) can be measured accurately. The present study was designed to measure silicon levels in the fibrous capsules of patients with silicone-gel breast implants, saline breast implants, and silicone inflatable penile prostheses. Baseline control silicon levels were obtained from the breast tissue of patients undergoing breast reduction, who had no exposure to breast implants. All silicon measurements were carried out using atomic absorption spectrometry with a graphite furnace. Silicon was measured in a normal heptane extract of silicone from dried tissue. The mean silicon levels in 16 breast tissue control samples from 8 patients undergoing breast reduction varied from 0.025 to 0.742 micrograms/gm with the median mean being 0.0927. The median silicon level in capsules from six patients with saline implants was 7.7 micrograms/gm (range, 1.9-36.6 micrograms/gm). The median silicon level in capsules from five patients with silicone inflatable penile prostheses was 19.5 micrograms/gm (range, 1.9-34.8 micrograms/gm). Although the levels of silicon in capsules of patients with saline breast prostheses and penile implants were higher than in control samples, they were much lower than those from the capsules of the 58 gel implants (median, 9,979 micrograms/gm; range, 371-152,000 micrograms/gm).(ABSTRACT TRUNCATED AT 250 WORDS)

Breast↗
PubMed1995

Fibroblast responses to cytokines are maintained during aging.

Impaired wound healing in older individuals may result from a global deficit of fibroblast activity or a decreased response of aged fibroblasts to stimulation by inflammatory cytokines. Twenty-eight fibroblast cell strains were developed from normal human skin aged 3 days to 84 years. Mitogenic response to cytokines, epidermal growth factor, tumor necrosis factor-alpha, platelet-derived growth factor or fetal bovine serum was determined using a 4-hour 3H-thymidine incorporation assay. Synthesis of collagen and noncollagen proteins was determined basally and in response to transforming growth factor-beta using a 6-hour 3H-proline incorporation assay. Neither the mitogenic response to cytokine stimulation (p > 0.3) nor the synthesis of collagen and noncollagen protein after transforming growth factor-beta stimulation (p > 0.4) varied with the age of the cell donor. Individual cell lines' response to cytokine stimulation varied widely, reflecting differences commonly seen in patients' wound-healing abilities. Cellular responses to wound-healing cytokines are preserved as people age. Abnormalities in wound healing in older patients may be the result of altered immune initiation of healing or the cumulative result of concomitant disease.

Adolescent↗
PubMed1995

Importance of reflux symptoms in functional dyspepsia.

The relation between symptom severity in gastro-oesophageal reflux disease (GORD) and quantitated oesophageal acid reflux is variable. Furthermore, when oesophageal acid exposure lies within the conventional normal range, the cause of the symptoms is unknown. This prospective study evaluated 24 hour ambulatory oesophageal pH profiles in relation to objective symptom scores in 100 dyspeptic patients who were free from ulcer and gall stones. Twenty patients had raised oesophageal acid exposure and reflux symptoms consistent with GORD, and 80 had oesophageal pH profiles within the conventional normal range. Forty four of the 80 had severe or moderate reflux symptoms and were classified as having reflux like functional dyspepsia (RFD); 36 had minimal or absent reflux symptoms, and were categorised as having non-reflux dyspepsia (NFD). While oesophageal pH profiles lay within the conventional normal range in both functional dyspepsia subgroups, patients with RFD had consistently greater acid exposure values as follows: mean (SEM) total oesophageal acid exposure time, RFD 16.2 (2.56) min v NFD 9.05 (2.0) min (p < 0.03); percentage of time with pH < 4, RFD 1.4 (0.2) v NFD 0.8 (0.2) (p < 0.03); DeMeester scores, RFD 12.8 (0.5) v NFD 11.4 (0.4) (p < 0.03). The RFD group had a pain/reflux event correlation of 23.8 (5.3)% v 8.1 (3.7)% for the NFD group (p < 0.01). This study shows that patients with RFD have oesophageal acid exposure that lies below the diagnostic threshold for GORD, but exceeds that of patients with NFD. The high pain/reflux event correlation in RFD, suggests that subthreshold oesophageal acid exposure may be associated with troublesome reflux symptoms.

Adult↗
PubMed1995

Disabling parkinsonism due to lithium: a case report.

Two cases of disabling parkinsonism have been previously reported in association with lithium treatment and only one occurred without other signs of lithium toxicity. We report a case of an elderly female who suddenly developed disabling parkinsonism, apparently as a side effect from treatment with lithium carbonate without other signs of lithium toxicity. All neurologic symptoms completely resolved on discontinuation of lithium. Resuming lithium at serum levels below 0.7 mmol/L resulted in no further neurologic side effects, but serum levels of 0.7 to 0.9 mmol/L resulted in the return of mild Parkinson's symptoms. Older age, longer duration of lithium treatment, and high therapeutic levels of lithium may be risk factors for this side effect. Implications for clinicians are discussed.

Aged↗
PubMed1995

Syme ankle disarticulation in peripheral vascular disease and diabetic foot infection: the one-stage versus two-stage procedure.

A prospective randomized trial compared performing a Syme ankle disarticulation using a one-stage versus Wagner's two-stage technique. Surgery was performed at two University Medical Centers where patients underwent amputation surgery for gangrene or nonsalvageable diabetic foot infection. Those undergoing surgery subsequent to trauma or congenital anomaly were eliminated. Initially, 21 patients were randomized into one-stage and two-stage surgery. The randomization was stopped for ethical reasons when the results of both procedures appeared to be similar. The next 22 consecutive patients underwent 23 Syme ankle disarticulations in one-stage surgery. Selection of amputation level was based on clinical examination, transcutaneous oximetry as a measure of vascular inflow, serum albumin as a measure of tissue nutrition, and total lymphocyte count as a measure of immunocompetence. As a total group, 31 of 44 amputations progressed to amputation wound healing and prosthetic limb fitting. In the randomized group, 9 of 13 one-stage and 5 of 8 two-stage surgeries healed. In the subsequent consecutive group, 17 of 23 healed. In all, 26 of 36 one-stage and 5 of 8 two-stage surgeries healed successfully. We concluded from this study that Syme ankle disarticulation may be performed as safely in one stage as in two stages in properly selected patients and, therefore, recommend the one-stage Syme ankle disarticulation in those patients suitable for this level amputation.

Adult↗
PubMed1995

Characterization of Gallus domesticus alpha-N-acetyl-galactosaminidase blood group A2 activity.

Soluble A antigens and an enzyme-linked immunosorbent assay (ELISA) using type A2 erythrocyte membranes were used to study the activity of an alpha-N-acetyl-galactosaminidase from Gallus domesticus (domestic chicken). The enzyme readily hydrolyzed the terminal N-acetyl-alpha-D-galactosamine of the A antigen under a variety of conditions, converting it to H antigen. Conversion of the A antigen to H antigen produces blood type O, which is universally transfusable. These preliminary studies are important in determining optimal conditions for enzymatic conversion of blood type A to O if efficient large scale production of enzymatically converted, universally transfusable red blood cells is to be achieved.

ABO Blood-Group System↗
PubMed1995

Surgical Treatment of Metastatic Brain Tumors.

Metastasis to the brain is a major cause of mortality and morbidity in patients with cancer. Lung, breast, and renal cancers as well as melanomas are particularly prone to producing this complication. Brain metastases may be clinically silent or may be detected as a result of various neurologic symptoms, and they may present in patients with or without extracranial manifestations of the primary cancer. Various management approaches are available, and decisions on which treatment will provide most benefit are best made with multidisciplinary input. Surgical resection is considered for patients with single or adjacent metastases who are in good performance status and whose systemic cancer, if present, is likely to be indolent or controlled.

Journal Article↗
PubMed1995

Breast self-examination: attitudes and practices among young women in Europe.

Breast self examination (BSE) is recommended for the early detection of breast cancer in the European Code against Cancer. Evidence from North America suggests that there is reasonable public awareness of its importance, but compliance with regular BSE is reported by only a minority of young women. Attitudes to and practice of BSE has rarely been studied outside North America. In the present study, attitudes to BSE were evaluated by questionnaire in a sample of 16,486 students aged 17-30 from 20 European countries. Frequency of BSE practice was reported by the 9,181 women in the sample. Information on public recommendations concerning BSE was obtained from cancer organizations in each country. The data were collected as part of the European Health Behaviour Survey, an international study on health beliefs and health behaviour. The results showed that BSE was recommended in 16 countries and 'breast awareness' in two, while two countries did not recommend self-examination. 54% of women reported as never having practiced BSE. Regular practice (monthly) was reported by only 8% of the sample, with another 36% reporting occasional BSE. Significant differences emerged between centres in different countries ranging from 6% to 15% reporting regular BSE. Attitude towards BSE was a significant predictor of BSE practice within each centre and across all centres combined. Attitudes towards BSE were significantly less positive in the two centres from countries without BSE recommendations than in the others, but levels of practice were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Adjuvant chemotherapy for bladder cancer. Standard of care or unproven therapy?

The failure of radical cystectomy to cure the majority of patients with muscle invasive transitional cell carcinoma of the bladder has prompted clinical trials evaluating adjuvant chemotherapy. No properly conducted prospective trials are available to support unequivocally the application of pre- or postsurgical chemotherapy. A large trial comparing chemotherapy with no chemotherapy and standard treatment (cystectomy) is nearing completion. The results will determine whether or not adjuvant chemotherapy becomes the standard of care.

Carcinoma, Transitional Cell↗