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Biomedical subjects

K Stanley

Publications and source records attributed to K Stanley.

At least 19 recordsLinked to original sources
PubMed1992

Signal transduction by the epidermal growth factor receptor is attenuated by a COOH-terminal domain serine phosphorylation site.

It has been proposed that the acute desensitization of epidermal growth factor receptor (EGF-R) function can be accounted for, in part, by the effect of EGF to increase phosphorylation of the receptor at Ser1046/7 (Countaway, J.L., Nairn, A.C., and Davis, R.J. (1992) J. Biol. Chem. 267, 1129-1140). Here, we show that the mutational removal of this phosphorylation site causes an activation of EGF-R function and a potentiation of signal transduction. The mechanism of potentiation results from 1) defective down-regulation of the EGF-R when cells are incubated with high concentrations of EGF; and 2) increased EGF-stimulated tyrosine phosphorylation. The increased EGF-stimulated phosphorylation is associated with an alteration of the apparent specificity of tyrosine phosphorylation and is independent of the down-regulation defect. Together, these data strongly support the hypothesis that Ser1046/7 is a biologically significant site of regulatory phosphorylation of the EGF-R.

Amino Acid Sequence↗
PubMed1992

Effect of hysterectomy on anorectal and urethrovesical physiology.

To investigate whether vaginal or total abdominal hysterectomy is associated with changes in anorectal and urethrovesical physiology, 26 women were studied before operation and six weeks and six months afterwards. The results showed a postoperative increase in both rectal and vesical sensitivity (p less than 0.01). Similar results were observed irrespective of the type of hysterectomy. No significant changes in rectal or bladder compliance were noted, and anal pressure and urethral pressure and length were unchanged after surgery. Whole gut transit was not affected by hysterectomy. Urinary symptoms occurred de novo in 6/26 women and gastrointestinal symptoms in 2/26 women. These results show that significant changes in rectal and vesical sensitivity occur after hysterectomy for benign disease. These persist for at least six months postoperatively but are not always associated with development of urinary or gastrointestinal symptoms.

Adult↗
PubMed1992

Mutational removal of the major site of serine phosphorylation of the epidermal growth factor receptor causes potentiation of signal transduction: role of receptor down-regulation.

The major site of epidermal growth factor receptor (EGF-R) serine phosphorylation is located within the COOH-terminal domain of the receptor at Ser1046/7. We have previously demonstrated that this phosphorylation site accounts for the acute desensitization of the EGF-R observed in EGF-treated cells. Here we show that the mutational removal of this negative regulatory phosphorylation site causes potentiation of signal transduction by the EGF-R. This potentiation can be accounted for in part by a block in the EGF-stimulated down-regulation of the EGF-R. These data indicate that the SER1046/7 phosphorylation site may have a regulatory role during long term incubation of cells with mitogenic concentrations of EGF.

Allosteric Regulation↗
PubMed1991

Constitutive phosphorylation of the epidermal growth factor receptor blocks mitogenic signal transduction.

The epidermal growth factor (EGF) receptor is phosphorylated by protein kinase C at Thr654. It has been proposed that the phosphorylation of this site is an important regulatory mechanism for the control of EGF receptor function. However, the physiological significance of the phosphorylation of EGF receptor Thr654 in intact cells is not understood. To address this question, the design of an experimental strategy is required that can be used to distinguish between the pleiotropic effects of kinase C activation and the specific effects of kinase C that are mediated by the phosphorylation of the EGF receptor at Thr654. The approach that we used was to examine the function of EGF receptors that are constitutively phosphorylated at residue 654. It was observed that the constitutive phosphorylation of the EGF receptor blocked mitogenic signal transduction by the receptor. These data are consistent with the hypothesis that the phosphorylation of the EGF receptor at residue 654 in intact cells inhibits EGF-stimulated cellular proliferation.

Animals↗
PubMed1990

The 68 kDa protein of signal recognition particle contains a glycine-rich region also found in certain RNA-binding proteins.

Signal recognition particle (SRP) interacts with the signal sequence in nascent secretory and membrane proteins and directs them to the membrane of the endoplasmic reticulum. Membrane targeting is mediated by the 68 and the 72 kDa proteins of SRP. We have cloned and sequenced cDNA encoding the 68 kDa protein of canine signal recognition particle (SRP68). SRP68 is a basic protein comprised of 622 amino acid residues. Close to the amino terminus there is a glycine-rich region which SRP68 has in common with some RNA-binding proteins. SRP68 shares no detectable similarity to any of the proteins in data libraries.

Amino Acid Sequence↗
PubMed1990

The control of breast cancer. A World Health Organization perspective.

The greatest decrease in breast cancer mortality is likely to derive from applying globally existing therapies at an earlier stage. A high priority of the World Health Organization (WHO) cancer control program is the outreach approach that promotes worldwide access to cancer therapies of proven values. Therefore, the first priority in national health programs for breast cancer is to encourage patients to present for diagnosis and treatment at an earlier stage of the disease. In the development of guidelines for the early detection of breast cancer, the WHO emphasizes the importance of appropriate widespread coverage of high-risk groups as opposed to repetitive screening of low-risk groups, so that early detection will be effective. A WHO/USSR controlled trial of breast self-examination and community-based adjuvant therapy is helping to develop the WHO global recommendations for the control of breast cancer. Depending on the extent of the breast cancer problem, the local resources, and the cultural situation, national health strategies should include all three main elements--public education, early detection, locally available treatment, or a combination of these to a national comprehensive program for the control of breast cancer.

Adult↗
PubMed1989

The gene for the human putative apoE receptor is on chromosome 12 in the segment q13-14.

We have previously described the cDNA coding for a new lipoprotein receptor that contains domains closely related to the ligand-binding domain of the LDL receptor. We have now investigated the localization of the gene for this new receptor by hybridization of the cDNA to panels of rodent cells containing subsets of human chromosomes and by in situ hybridization of the cDNA to chromosomes. The gene maps to 12q13-14, a known hot spot for chromosomal rearrangements in human neoplasia. Of particular interest is the frequent involvement of the 12q13-14 segment in clonal abnormalities in lipomas and myxoid liposarcomas, and it is possible that LRP may play a role in the pathogenesis of such tumors.

Animals↗
PubMed1989

The gene for human complement C9 is on chromosome 5.

By hybridizing a cloned cDNA coding for human complement factor C9 to hybrid cells containing subsets of human chromosomes on a rodent background, we have determined that the human gene for C9 is localized on chromosome 5.

Autoradiography↗
PubMed1989

Membrane-anchored and soluble forms of betaglycan, a polymorphic proteoglycan that binds transforming growth factor-beta.

Transforming growth factors beta 1 and beta 2 bind with high affinity to the core protein of a 250-350-kD cell surface proteoglycan. This proteoglycan (formerly referred to as the type III TGF-beta receptor) coexists in many cells with the receptor implicated in TGF-beta signal transduction (type I TGF-beta receptor), but its function is not known. We report here that soluble TGF-beta-binding proteoglycans are released by several cell types into the culture media, and can be found in serum and extracellular matrices. As has been shown for the membrane-bound form, the soluble proteoglycans have a heterogeneous core protein of 100-120 kD that carries chondroitin sulfate and/or heparan sulfate glycosaminoglycan chains and a small amount of N-linked carbohydrate. The membrane-bound form of this proteoglycan is hydrophobic and associates with liposomes, whereas the soluble forms lack a membrane anchor and do not associate with liposomes. Differences in the electrophoretic migration of the soluble and membrane forms of this proteoglycan suggest additional structural differences in their core proteins and glycosaminoglycan chains. These soluble and membrane-bound proteoglycans, for which we propose the name "betaglycans," might play distinct roles in pericellular retention, delivery, or clearance of activated TGF-beta.

Animals↗
PubMed1988

Heterodimeric transforming growth factor beta. Biological properties and interaction with three types of cell surface receptors.

Type beta transforming growth factors (TGF) are disulfide-linked homo- and heterodimers of two related polypeptide chains, beta 1 and beta 2. The homodimers TGF-beta 1 and TGF-beta 2 are widely distributed, but the heterodimer TGF-beta 1.2 has been found only in porcine platelets (Cheifetz, S., Weatherbee, J.A., Tsang, M.L.-S., Anderson, J.K., Mole, J.E., Lucas, R., and Massagué, J. (1987) Cell 48, 409-415). Here we characterize the receptor binding and biological properties of TGF-beta 1.2 and compare them with those of TGF-beta 1 and TGF-beta 2. Three types of cell surface receptors previously identified by affinity labeling with 125I-TGF-beta 1 are available for binding to TGF-beta 1.2. These three types of receptors are detected as 65-kDa (type I), 85-95-kDa (type II), and 250-350-kDa (type III) affinity-labeled receptor complexes on electrophoresis gels. They co-exist in many cell types, have high affinity for TGF-beta 1, and varying degrees of affinity for TGF-beta 2. Of the 11 cell lines screened in the present study none showed evidence for additional receptor types that would bind TGF-beta 2 but not TGF-beta 1. In receptor competition studies, TGF-beta 1, TGF-beta 1.2, and TGF-beta 2 competed for binding to type I and type II receptors with a relative order of potencies of 16:5:1 and 12:3:1, respectively, whereas all three forms of TGF-beta were equipotent as ligands for the type III receptors. The three forms of TGF-beta were equally potent at stimulating the biosynthesis of extracellular sulfated proteoglycan in BRL-3A rat liver epithelial cells, a response that presumably involves the type III receptor present in these cells. In contrast, the ability of the three ligands to inhibit the growth of B6SUt-A multipotential hematopoietic progenitor cells which display only type I receptors decreased in the order TGF-beta 1, TGF-beta 1.2, and TGF-beta 2 with a relative potency of 100:30:1. The results indicate that the presence of one beta 1 chain in TGF-beta 1.2 increases (with respect to TGF-beta 2) the biological potency and binding affinity toward receptor types I and II, but the presence of a second beta 1 chain in the dimer is required for full potency.

Binding, Competitive↗
PubMed1988

Cancers of the stomach, lung and breast: mortality trends and control strategies.

Mortality trends for the three most common tumours--stomach, lung and breast cancer--were evaluated for nine countries. Stomach cancer is decreasing sharply and consistently in the countries studied. However, virtually all of this decline can be attributed to improvements in food preservation techniques and the resulting change in diet, rather than any action of the medical community. Lung cancer is rapidly increasing in most countries, especially in women, and is likely to become the dominant cancer worldwide by the end of this century. So far, only comprehensive tobacco-control programmes in the United Kingdom and Finland have succeeded in reversing the upward trend in lung-cancer mortality. Breast-cancer death rates are generally rising, although some recent, but probably short-term, declines have been seen. Effectiveness of the currently available approaches for each of the common cancers is summarized in Table 1. Because about half of worldwide mortality from cancer occurs in developing countries and resources in these countries are severely limited, care needs to be taken in the selection of proper priorities (18). The most effective tool we have at this time to deal with these tumours is the control of tobacco for the prevention of lung cancer. Comprehensive national programmes, consisting of legislative and education measures, are needed. The greatest decrease in breast-cancer mortality is likely to be the result of early detection and prompt treatment of the disease; public awareness of the value of early detection is an important factor here. Fortunately, mortality from stomach cancer is decreasing on its own, as little can be done to control this disease otherwise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Bladder cancer: approaches to prevention and control.

Bladder cancer is the twelfth most common cancer globally, with approximately 170 000 new cases each year; a third of these cases are in the developing countries. There are two major etiological types. The first is more common in the industrialized countries and is associated with exposure to certain occupational and environmental carcinogens, but most importantly with tobacco smoking. The second type is associated with Schistosoma haematobium infection of the urinary tract and is one of the most frequent tumours in eastern Mediterranean and African countries. Both types of bladder cancer are largely preventable. Comprehensive education and legislative approaches are recommended to reduce tobacco consumption and exposure to industrial carcinogens. Safe and effective drugs are available to treat schistosomiasis within integrated control programmes in endemic areas.

Humans↗
PubMed1987

Women and cancer.

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Cross-Cultural Comparison↗