Osteopathy in general practice.
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Family Practice↗
Biomedical subjects
K Burns
Publications and source records attributed to K Burns.
Chlamydia psittaci infection in sheep in Northern Ireland.
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Abortion, Veterinary↗
Interactions of calreticulin with proteins of the endoplasmic and sarcoplasmic reticulum membranes.
The ability of [125I]calreticulin to bind to membrane fractions isolated from different muscle and non-muscle tissues was examined by a protein overlay technique. Specific [125I]calreticulin binding proteins were detected in rat liver smooth and rough endoplasmic reticulum and Golgi, in canine pancreatic microsomes, and in rabbit skeletal muscle sarcoplasmic reticulum. These proteins were confined only to membranes that contain calreticulin; they were not found in rat liver mitochondria or cytosol. [125I]Calreticulin binds to a 50-kDa protein and a number of lower M(r) (20,000-38,000) endoplasmic reticulum membrane proteins and to 30-kDa protein in skeletal muscle sarcoplasmic reticulum. Full-length calreticulin and the carboxyl-terminal region (C-domain) of the protein both competed with [125I]calreticulin for binding to the membrane proteins. Binding of [125I]calreticulin to pancreatic microsomes was also partially inhibited by the N-domain and to a lesser extent by the P-domain of the protein. We conclude that calreticulin interacts with the endoplasmic reticulum membrane proteins mainly through its carboxyl-terminal domain and that the endoplasmic and sarcoplasmic reticulum membranes may contain different calreticulin binding proteins.
Animals↗
Calreticulin in T-lymphocytes. Identification of calreticulin in T-lymphocytes and demonstration that activation of T cells correlates with increased levels of calreticulin mRNA and protein.
Ca2+ is an essential second messenger for T cell activation, but the exact mechanisms of its action are poorly understood. The cytosolic Ca2+ concentration is significantly increased upon the stimulation of T cells with either mitogen, cross-linking antibodies, or their cognate ligands. In this study, expression of calreticulin, a major Ca(2+)-binding (storage), KDEL protein of the endoplasmic reticulum was examined in resting and concanavalin A (ConA)-stimulated mouse and human T-lymphocytes. Both resting, mouse and human lymphocytes contain very low levels of calreticulin mRNA and protein. Mouse splenocytes stimulated with ConA exhibited an induction in calreticulin mRNA which peaked by Day 4. A 5-fold increase in the immunoreactive calreticulin protein band was also observed in the cells during this period of stimulation. Similarly when human lymphocytes were cultured with ConA a significant increase in the levels of the calreticulin mRNA and protein was observed. The peak of calreticulin mRNA was observed at Day 1 rather than Day 4 as seen for the mouse. These results clearly demonstrate the presence of calreticulin, a Ca(2+)-binding protein originally characterized in muscle tissue, in activated T-lymphocytes. Furthermore, we show that expression of calreticulin correlates with T-lymphocyte activation. Our results suggest that calreticulin may be involved in the signaling pathway for the induction of Ca(2+)-dependent processes and may represent one regulatory mechanism operating in activation of T-lymphocytes.
Amino Acid Sequence↗
Deletion (14) (q24.3q32.1): evidence for a distinct clinical phenotype.
We report on a 4-year-old girl with distinctive facial features (redundant skin, bushy eyebrows, narrow palpebral fissures, short, upturned nose, epicanthal folds, and a long upper lip with well-defined philtrum) who has an interstitial deletion of chromosome 14 including band 14q31, designated as 46,XX,del(14)(pter-->q24.3::q32.1-->qter). Comparison with previously reported patients with deletions of 14q involving band 14q31 suggests that there is a distinctive clinical phenotype associated with this deletion. Our patient had dental abnormalities (3 maxillary and 3 mandibular incisors) not described in the other patients.
Abnormalities, Multiple↗
Effects of position and mattress overlay on sacral and heel pressures in a clinical population.
A comparison of pressure reducing properties of alternating air, static air, and water mattress overlays was conducted with 57 patients in a surgical intensive care unit. Sacral and heel pressures in both recumbent and semi-Fowler's positions were tested for each surface using a repeated measures design. Mean pressures for the alternating air mattress were significantly higher than pressures with other surfaces, regardless of position or site. There were significant main effects for position and site, with higher pressures in the semi-Fowler's position and at the sacral site. A significant interaction between surface, site, and position was found. Pressure sores developed in eight patients, but the incidence was not significantly different across groups. A pressure measuring device constructed from available clinical materials proved to be both sensitive and reliable. The findings suggest alternating air overlays should be avoided, and that positioning and periodic position change to reduce sacral pressures for patients requiring prolonged upper body elevation is important.
Aged↗
Expression and purification of recombinant and native calreticulin.
Calreticulin is a 60-kDa Ca(2+)-binding protein of the endo(sarco)plasmic reticulum membranes of a variety of cellular systems. The protein binds approximately 25 mol of Ca2+ with low affinity and approximately 1 mol of Ca2+ with high affinity and is believed to be a site for Ca2+ binding/storage in the lumen of the endo(sarco)plasmic reticulum. In the present study, we describe purification procedures for the isolation of recombinant and native calreticulin. Recombinant calreticulin was expressed in Escherichia coli, using the glutathione S-transferase fusion protein system, and was purified to homogeneity on glutathione-Sepharose followed by Mono Q FPLC chromatography. A selective ammonium sulfate precipitation method was developed for the purification of native calreticulin. The protein was purified from ammonium sulfate precipitates by diethylaminoethyl-Sephadex and hydroxylapatite chromatography procedures, which eliminates the need to prepare membrane fractions. The purification procedures reported here for recombinant and native calreticulin yield homogeneous preparations of the proteins, as judged by the HPLC reverse-phase chromatography and by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Purified native and recombinant calreticulin were identified by their NH2-terminal amino acid sequences, by their Ca2+ binding properties, and by their reactivity with anticalreticulin antibodies.
Amino Acid Sequence↗
Correlations between antepartum maternal metabolism and intelligence of offspring.
BACKGROUND: It is not clear to what extent maternal metabolism during pregnancy affects the cognitive and behavioral function of the offspring by altering brain development in utero. To investigate this question, we correlated measures of metabolism in pregnant diabetic and nondiabetic women with the intellectual development of their offspring. METHODS: The study included 223 pregnant women and their singleton offspring: 89 women had diabetes before pregnancy (pregestational diabetes mellitus), 99 had the onset of diabetes during pregnancy (gestational diabetes mellitus), and 35 had normal carbohydrate metabolism during their pregnancy. We correlated measures of maternal glucose and lipid metabolism (fasting plasma glucose levels, hemoglobin A1c levels, episodes of hypoglycemia, episodes of acetonuria, and plasma beta-hydroxybutyrate and free fatty acid levels) with two measures of intellectual development in the offspring--the mental development index of the Bayley Scales of Infant Development, given at the age of two years, and the Stanford--Binet Intelligence Scale, given at the ages of three, four, and five years and expressed as an average of the three scores. RESULTS: After correction for socioeconomic status, race or ethnic origin, and patient group, the children's mental-development-index scores at the age of two years correlated inversely with the mothers' third-trimester plasma beta-hydroxybutyrate levels (r = -0.21, P less than 0.01); the average Stanford-Binet scores correlated inversely with third-trimester plasma beta-hydroxybutyrate (r = -0.20, P less than 0.02) and free fatty acid (r = -0.27, P less than 0.002) levels. No other correlations were significant. Including various perinatal events (e.g., prematurity and acidemia) in the analyses did not alter the results. CONCLUSIONS: Maternal diabetes during pregnancy may affect behavioral and intellectual development in the offspring. The associations between gestational ketonemia in the mother and a lower IQ in the child warrant continued efforts to avoid ketoacidosis and accelerated starvation in all pregnant women.
3-Hydroxybutyric Acid↗
Dyadic disturbances in cocaine-abusing mothers and their infants.
A recently developed instrument for the quantification of mother-infant interaction, the Parent-Child Early Relationship Assessment (PCERA), was used to observe drug-abusing mothers and their infants. Compared to the standardization sample used in the development of the PCERA, these drug-abusing mothers (N = 5) showed a tendency toward rigidity and overcontrol in their parenting, a lack of enjoyment and pleasure in relating to their infants, and limited emotional involvement and responsivity in their interaction. An analysis of the dyadic behaviors showed an overall reduction in reciprocity, mutual enjoyment, and regulation of interaction between mother and infant.
Adult↗
Molecular cloning of cDNA encoding a 55-kDa multifunctional thyroid hormone binding protein of skeletal muscle sarcoplasmic reticulum.
A cDNA clone encoding 55-kDa multifunctional, thyroid hormone binding protein of rabbit skeletal muscle sarcoplasmic reticulum was isolated and sequenced. The cDNA encoded a protein of 509 amino acids, and a comparison of the deduced amino acid sequence with the NH2-terminal amino acid sequence of the purified protein indicates that an 18-residue NH2-terminal signal sequence was removed during synthesis. The deduced amino acid sequence of the rabbit muscle clone suggested that this protein is related to human liver thyroid hormone binding protein, rat liver protein disulfide isomerase, human hepatoma beta-subunit of prolyl 4-hydroxylase and hen oviduct glycosylation site binding protein. The protein contains two repeated sequences Trp-Cys-Gly-His-Cys-Lys proposed to be in the active sites of protein disulfide isomerase. Northern blot analysis showed that the mRNA encoding rabbit skeletal muscle form of the protein is present in liver, kidney, brain, fast- and slow-twitch skeletal muscle, and in the myocardium. In all tissues the cDNA reacts with mRNA of 2.7 kilobases in length. The 55-kDa multifunctional thyroid hormone binding protein was identified in isolated sarcoplasmic reticulum vesicles using a monoclonal antibody specific to the 55-kDa thyroid hormone binding protein from rat liver endoplasmic reticulum. The mature protein of Mr 56,681 contains 95 acidic and 61 basic amino acids. The COOH-terminal amino acid sequence of the protein is highly enriched in acidic residues with 17 of the last 29 amino acids being negatively charged. Analysis of hydropathy of the mature protein suggests that there are no potential transmembrane segments. The COOH-terminal sequence of the protein, Arg-Asp-Glu-Leu (RDEL), is similar to but different from that proposed to be an endoplasmic reticulum retention signal; Lys-Asp-Glu-Leu (KDEL) (Munro, S., and Pelham, H.R.B. (1987) Cell 48, 899-907). This variant of the retention signal may function in a similar manner to the KDEL sequence, to localize the protein to the sarcoplasmic or endoplasmic reticulum. The positively charged amino acids Lys and Arg may thus interchange in this retention signal.
Amino Acid Sequence↗
Density of lymphocytic infiltration of primary breast cancer does not affect short-term disease-free interval or survival.
Lymphocytic infiltration of breast cancer is often associated with a favourable prognosis. Seventy-seven women with operable breast cancer were followed for a minimum of 3 years. Tumours were frozen and sectioned by cryostat before staining with monoclonal antibodies using an immunoperoxide technique for total lymphocytes, helper/inducer, suppressor/cytotoxic, natural killer and B subsets. Lymphocyte density was assessed by light microscopy at x400 and divided at the 50th percentile to less than 30 and greater than or equal to 30 cells per high power field to give scanty and dense lymphocytic infiltration. The helper/suppressor lymphocyte ratio was greater than 1 in 45 patients but without improvement in survival or cancer recurrence. Natural killer and B lymphocytes were rarely seen in tumour sections. Poorly differentiated tumours excited a more marked lymphocytic infiltration (P less than 0.01). Neither the density of lymphocyte infiltration nor the ratio of helper to suppressor lymphocytes correlated with improved short-term survival or recurrence. These data suggest that the immune defence is ineffective in preventing spread from the primary tumour in breast cancer patients.
Adult↗
Molecular cloning of the high affinity calcium-binding protein (calreticulin) of skeletal muscle sarcoplasmic reticulum.
A cDNA clone encoding the high affinity Ca2+-binding protein (HACBP) of rabbit skeletal muscle sarcoplasmic reticulum was isolated and sequenced. The cDNA encoded a protein of 418 amino acids, but a comparison of the deduced amino acid sequence with the NH2-terminal amino acid sequence of the purified protein indicates that a 17-residue NH2-terminal signal sequence was removed during synthesis. This was confirmed by studies of in vitro translation of mRNA encoding the protein. Structural predictions did not reveal any potential transmembrane segments in the protein. The COOH-terminal sequence of the high affinity Ca2+-binding protein, Lys-Asp-Glu-Leu, is the same as that proposed to be an endoplasmic reticulum retention signal (Munro, S., and Pelham, H. R. B. (1987) Cell 48, 899-907). All of these characteristics suggest that the protein is localized in the lumen of the sarcoplasmic reticulum. The mature protein of Mr 46,567 contains 109 acidic and 52 basic amino acids. Structural predictions suggest that the first half of the molecule forms a globular domain of 8 anti-parallel beta-strands with a helix-turn-helix motif at the extreme NH2 terminus. The next one-third of the sequence is proline-rich. This segment can be subdivided into a charged region which contains a 17-amino acid repeat, followed by a proline, serine, and threonine-rich segment extending from Pro-246 to Thr-316. Thirty-seven acidic residues are clustered within 56 amino acids at the COOH terminus of the protein. Although the protein binds 1 mol of Ca2+/mol with high affinity, no "EF-hand" consensus sequence was observed in the protein. The acidic COOH terminus, however, could account for the low affinity, high capacity Ca2+ binding observed in the protein. In agreement with other involved laboratories, we have chosen the name calreticulin for the protein.
Amino Acid Sequence↗
The high-affinity calcium binding protein of sarcoplasmic reticulum. Tissue distribution, and homology with calregulin.
The 55-kDa high-affinity calcium binding protein (HACBP) was first identified and isolated from skeletal muscle sarcoplasmic reticulum (SR). Using polyclonal antibodies raised against the HACBP isolated from skeletal muscle we have identified this protein in cardiac and smooth muscle as well as in non-muscle cells. Although the 55-kDa protein has a size, properties and localization similar to that of calsequestrin, the two proteins are immunologically distinct. The NH2-terminal sequence of uterine HACBP is also completely different from that of calsequestrin but it is identical to that of rabbit liver calregulin, a recently identified calcium binding protein. Indirect immunofluorescence staining of frozen sections and culture cells from a variety of tissues shows that the 55-kDa protein localizes predominantly to junctional SR and T-tubule areas in skeletal muscle, to SR in smooth and cardiac muscle cells, and to ER in a variety of non-muscle cells. These data show that the protein is present in a wide variety of tissues and suggest that it is a protein common for both sarcoplasmic and endoplasmic reticulum membranes.
Animals↗
Peripheral membrane proteins of sarcoplasmic and endoplasmic reticulum. Comparison of carboxyl-terminal amino acid sequences.
Peripheral endoplasmic reticulum membrane proteins residing in the lumen of the endoplasmic reticulum occupy the same space as other secreted proteins. The presence of a four amino acid salvage or retention signal (KDEL-COOH = Lys-Asp-Glu-Leu-COOH) at the carboxyl-terminal end of peripheral membrane proteins has been shown to represent a signal or an essential part of a signal for their retention within the endoplasmic reticulum membrane. In heart and skeletal muscle, a number of sarcoplasmic reticulum proteins have recently been identified which are peripheral membrane proteins. The high-affinity calcium-binding protein (55 kilodaltons (kDa] appears to conform to the above described mechanisms and contains the KDEL carboxyl-terminal tetrapeptide. Thyroid hormone binding protein is present in the sarcoplasmic reticulum, in addition to its endoplasmic reticulum location, and has a modified but related tetrapeptide sequence (RDEL = Arg-Asp-Glu-Leu), which also probably functions as the retention signal. Calsequestrin and a 53-kDa glycoprotein, two other peripheral membrane proteins residing in the lumen of the sarcoplasmic reticulum, do not contain the KDEL retention signal. The sarcoplasmic reticulum may have developed a unique retention mechanism(s) for these muscle-specific proteins.
Amino Acid Sequence↗
Crohn's disease angiographically mimicking vascular malformation or neoplasm.
We report a young woman with lower gastrointestinal bleeding in whom, angiographically and surgically, the offending cecal lesion appeared to be a vascular malformation or neoplasm. Pathologically, Crohn's disease associated with extremely prominent vascularity was discovered to be responsible for this unusual appearance and the bleeding.
Adult↗
How do you use a double-lumen endobrochial tube?
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Bronchi↗
Prognostic significance of the DNA content of human breast cancer.
The DNA content of paraffin embedded primary tumour tissue has been measured by flow cytometry in 354 patients with operable breast cancer. Tumour ploidy significantly correlated with tumour size, histological grade, and with menopausal status. No significant correlation with oestrogen receptor status or lymph node involvement was found. Patients with diploid cancers had a significantly improved short term survival and disease-free interval (DFI) compared with patients having aneuploid tumours. However, no difference in survival or DFI was shown after longer term follow-up (median 84 months). Multivariate analysis showed no independently significant prognostic value for tumour ploidy. No patient in this study received adjuvant therapy.
Aneuploidy↗