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Biomedical subjects

S K Smith

Publications and source records attributed to S K Smith.

230 records · Page 13Linked to original sources
PubMed1978

Photodestruction of pheomelanin: role of oxygen.

Pheomelanin, the red-brown polymeric pigment in the skin and hair of red-headed humans, is composed of a protein fraction covalently bound to a colored chromophore. Photolysis of aerated aqueous phemelanin solutions, isolated from human red hair, results in destruction of the chromophore and liberation of the peptide fraction. The rate of photolysis depends on the pH and the concentration of both pigment and oxygen and is slightly inhibited by the enzyme superoxide dismutase (superoxide:superoxide oxidoreductase EC 1.15.1.1). Pheomelanin photolyzed in the presence of nitroblue tetrazolium results in the formation of a blue diformazan, whether or not oxygen is present. Superoxide dismutase inhibits the aerobic photoreduction of nitroblue tetrazolium whereas, in the absence of oxygen, no inhibition is observed. These experiments strongly suggest the involvement of superoxide in the aerobic photolysis of pheomelanin and point out a possible mechanism for ultraviolet-induced cell damage in redheads.

Amino Acids↗
PubMed1978

Rapid enlargement of carniopharyngioma in pregnancy.

A patient is described in whom rapid enlargement of a craniopharyngioma during pregnancy caused visual disturbance. The tumour was removed at 29 weeks gestation and the patient went on to have a spontaneous labour and vaginal delivery at term.

Adult↗
PubMed1977

The effect of intravenous salbutamol upon plasma and urinary potassium during premature labour.

Plasma potassium and urinary potassium excretion were measured in eight patients in premature labour treated with salbutamol, and in ten patients at full term in spontaneous labour. There was a significant fall in plasma potassium concentration following salbutamol infusion, but no change during labour in the control groups. Urinary potassium excretion was similar in both groups.

Adult↗
PubMedDate not supplied

Bilaterality and recurrence rates for lobular breast cancer: considerations for treatment.

BACKGROUND: The purpose of this study was to evaluate the tumor biology with respect to bilaterality and recurrence rates for bilateral infiltrating lobular (IL) breast carcinoma in comparison with other histological types. METHODS: A prospectively accrued data base containing 1,548 breast cancer cases as well as H. Lee Moffitt Cancer Center's cancer registry compiled during the same period were queried for specific features relating to bilaterality and recurrence. The 116 patients in this study had been treated at the Comprehensive Breast Cancer Clinic and had documented bilateral breast cancer (invasive on situ). RESULTS: Eighty-two of the patients (70.7%) had metachronous breast cancer, and 34 (29.3%) had synchronous cancer. Although median follow-up times were short, the risk of developing breast cancer in the contralateral breast after the diagnosis of cancer in the ipsilateral breast was estimated to be 0.7% per patient-year of follow-up. Recurrence rates for IL cancers were compared with those for invasive ductal (ID) and for ID + IL cancers. IL cancers recurred 8.1% of the time, whereas ID cancers recurred at a rate of 7.8%. Recurrences were equally divided between local and distant sites. CONCLUSIONS: Although IL cancers have demonstrated insidious behavior, their incidence of bilaterality is only slightly higher than other histologies and their rates of recurrence are low when properly evaluated and treated. The risk to the opposite breast also appears to be low. These data do not support the routine use of blind contralateral biopsy or prophylactic mastectomy.

Breast Neoplasms↗
PubMedDate not supplied

Regulation of angiogenesis in the endometrium.

A crucial stage in pregnancy is the implantation of the embryo into the endometrium. The endometrium, which is situated in the lining of the uterus, is a complex structure consisting of a single epithelial layer overlying a mesenchymal stroma. Cyclical growth of the endometrium under the influence of ovarian steroids results in the establishment of a receptive endometrium. If implantation fails, or is deliberately prevented by the use of fertility regulation, the endometrium is shed by the process of menstruation. This unique system of cyclic tissue regeneration is dependent on the cyclical growth and regression of the blood vessels that supply the endometrium. Little attention has been paid to this crucial aspect of human reproduction but it now appears that many disorders that reduce the quality of life of modern women, such as heavy menstruation, endometriosis, breakthrough bleeding and infertility, might have their basis in disorders of the endometrial vasculature.

Endometriosis↗
PubMedDate not supplied

Evaluation of a (1)h-(13)c NMR spectral library.

A simple database of (13)C/(1)H-(13)C spectral lists for 11 673 natural products was created in standard commercial database format. Over 50% of the spectra were predicted using HOSE code descriptors derived from the 50% of spectra having experimental values. Prediction errors obtained by prediction of and comparison to the experimental spectra revealed an exponentially decaying dependence between the average absolute error and the depth of the matching HOSE codes. A subset of the library containing over 1000 (1)H-(13)C assigned experimental spectral lists were used to test against eight alternate query data sets. These sets represent query data from various combinations of 1D-(13)C, 1D-DEPT, and 2D-(1)H-(13)C spectra. Simulated query lists were generated using Monte Carlo methods. As expected, queries based on 2D-(1)H-(13)C data were more likely to find the correct match under unfavorable conditions.

Journal Article↗
PubMedDate not supplied

Angiogenesis, vascular endothelial growth factor and the endometrium.

Angiogenesis is an essential component of endometrial renewal. The formation of new vessels depends on interactions between various hormones and growth factors, and this review focuses on the expression of angiogenic growth factors in the human endometrium. Peptide and non-peptide angiogenic factors interact during endometrial renewal, including epidermal growth factor (EGF), transforming growth factors (e.g. TGF-beta), platelet-derived endothelial growth factor/thymidine phosphorylase (PD-ECGF/TP), tumour necrosis growth factors and vascular endothelial growth factor (VEGF). Their role in the proliferation and migration of endothelial cells from pre-existing vessels is described, concentrating on VGEF and its receptors (VEG-R1 and -R2), and the fibroblast growth factor (FGF) family. The actions of the products of the VEGF gene are outlined, and the hormonal and non-hormonal control of their localization in the human endometrium and biological actions on vasculature and coagulation are described. Finally, the role of VEGF in menorrhagia is assessed.

Animals↗
PubMedDate not supplied

Our chemical burn experience: exposing the dangers of anhydrous ammonia.

Although chemical injuries account for only a small number of one burn unit's cases, the diversity, resulting complications, and sequelae of these burns pose special problems. We reviewed a 19-year period of the chemical burn experience of our burn unit. The population of patients with these types of burns consisted of young men (mean age: 29.8 years), the majority of whom were injured on the job. Unique to our series is the largest collection of injuries (30%) resulting from the common fertilizer anhydrous ammonia. Another population of concern, accounting for 14% of the injuries in our unit, is that of patients injured at home with routine household cleaners. Nearly one half of those patients injured at home incurred injuries that required grafting. The cornerstone of chemical burn prevention and treatment involves education regarding the caustic nature of chemicals, proper handling, adequate protection, and copious irrigation of the wound at the scene. From the analysis of our retrospective review, adequate education and treatment at the scene appear to be well implemented in the industrial and farming communities. The focus of our education efforts should be directed toward the public and emphasize the safe use of household chemicals. Finally our review illuminated the potential benefit of immediate excision and grafting for decreasing the length of stay, complications, and loss of productivity.

Adult↗
PubMedDate not supplied

Perimenstrual complaints in women complaining of PMS, menorrhagia, and dysmenorrhea: toward a dismantling of the premenstrual syndrome.

Four groups of women were compared in terms of their perimenstrual symptoms, reported menstrual blood loss and period pain, and neuroticism scores: three patient groups were referred to a Gynaecology Outpatient Clinic because of menorrhagia (N = 101), PMS (N = 104), dysmenorrhea (N = 56), and a control group (N = 105). The three patient groups showed considerable overlap in a number of symptoms. This has led us to postulate three factors contributing to perimenstrual complaints: a) a 'timing factor' linked to the ovarian cycle; b) a 'menstruation factor,' associated with the buildup of the endometrium and its shedding; and c) a 'vulnerability factor,' one aspect of which, 'neuroticism,' was measured in this study. Depressive symptoms, which were the most important in leading women to seek help for their PMS, were related to all three factors. Depressive mood changes seemed to be linked to the 'timing factor' but were noticeably worse and more prolonged in women with high neuroticism, heavy bleeding, or severe pain. One premenstrual symptom, food craving, was of considerable interest. This was weakly related to neuroticism, not apparently affected by the 'menstruation factor' and differed in severity between those in the PMS group and the other three groups. It is potentially relevant that both carbohydrate craving and depression are linked to serotonergic changes in the brain, which may prove to be particularly marked in the late luteal phase.

Adolescent↗
PubMedDate not supplied

Aspartyl proteases from the intestinal brush border of Haemonchus contortus as protective antigens for sheep.

A novel pepsin-like aspartyl protease was identified as a component of Haemonchus galactose-containing glycoprotein (H-gal-GP), which is an integral membrane glycoprotein complex located on the intestinal cells of Haemonchus contortus, and a highly protective antigen for sheep. This molecule, designated HcPEP2, showed 50% sequence identity with a previously described aspartyl protease from H-gal-GP known as HcPEP1. Fractions of H-gal-GP, either containing both HcPEP1 and 2 or other lower molecular weight components of the complex, were evaluated as protective antigens in immunization - challenge trials in sheep. When separated from the rest of the complex by gel filtration in 8 m urea, the HcPEP1 and 2 fraction significantly reduced H. contortus egg counts by 48% and worm numbers by 36%, but the lower molecular weight components were not significantly protective. However, the HcPEP1 and 2 fraction did not protect if electro-eluted from SDS-dissociated H-gal-GP, nor did bacterially expressed recombinant HcPEP1, suggesting that conformational epitopes are important for inducing immunity.

Amino Acid Sequence↗
PubMedDate not supplied

Women's experiences of victimizing sexualization, Part I: Responses related to abuse and home and family environment.

Qualitative, interpretive research was conducted with ten adult women who felt that their experiences of learning about themselves as female and sexual had been harmful. The term "victimizing sexualization" was developed to identify this experience, and a thematic description of these women's experiences was derived. Components of their experiences were described within four major categories, including perceptions and descriptions directly related to abuse experiences, home and family environments, community and cultural characteristics, and longer term personal impacts. This article reports on two of the major thematic categories: perceptions and descriptions related to abuse experiences and home and family environment. Findings of this study establish "victimizing sexualization" as a meaningful women's health construct with important connections to feminist perspectives on women's lives.

Adult↗
PubMedDate not supplied

Women's experiences of victimizing sexualization, Part II: Community and longer term personal impacts.

This is the second of a two-part article describing the results of a qualitative study on women's experiences of victimizing sexualization. Ten adult women described their experiences of harmful learning about themselves as female and sexual. A four-part thematic description of women's experiences of victimizing sexualization was derived. This article reports on two of the major categories: community and cultural characteristics and longer term personal impacts. Findings of the study support the feminist position that the enactment of gender itself at social and cultural levels sometimes places women at risk for victimization.

Adult↗
PubMedDate not supplied

Influence of pulmonary endothelial cells on fetal lung development.

Culture medium conditioned by pulmonary endothelial cells stimulated proliferation of cultured fetal lung cells, as measured by increases in cell numbers, incorporation of tritiated thymidine into DNA, and incorporation of labeled choline into membrane phospholipids. Medium conditioned by several other cell culture preparations of fetal lung did not elicit these effects. The growth-promoting activity was found to be concentrated in fractions of 42,000 and 89,000 molecular weight (mol wt). In addition to promoting cell growth, medium conditioned by pulmonary endothelial cells also appeared to stimulate the incorporation of labeled choline into surfactant-associated phosphatidylcholine. These results suggest that pulmonary endothelial cells may produce factors that stimulate the growth and perhaps also the differentiation of fetal lung cells in culture.

Cell Communication↗