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C K Smith

Publications and source records attributed to C K Smith.

At least 55 records · Page 3Linked to original sources
PubMed1992

Characterization of zinc-binding sites in human stromelysin-1: stoichiometry of the catalytic domain and identification of a cysteine ligand in the proenzyme.

A determination of the zinc stoichiometry of the catalytic domain of the human matrix metalloproteinase stromelysin-1 has been carried out using enzyme purified from recombinant Escherichia coli that express C-terminally truncated protein. Atomic absorption spectrometry revealed that both the proenzyme (prostrom255) and the mature active form (strom255) contained nearly 2 mol of Zn/mol of protein. Full-length prostromelysin purified from a mammalian cell culture line also contained zinc in excess of 1 equiv. While zinc in prostrom255 could not be removed by dialysis against o-phenanthroline, similar treatment of mature strom255 resulted in the loss of one-half of the original zinc content. The peptidase activity of the zinc-depleted protein was reduced by greater than 85% but could be restored upon addition of Zn2+ or Co2+. Addition of a thiol-containing inhibitor to a CoZn hybrid enzyme resulted in marked spectral changes in both the visible and ultraviolet regions characteristic of sulfur ligation to Co2+. This direct evidence for an integral role in catalysis and inhibitor binding confirms the location of the exchangeable metal at the active site. To examine the environment of zinc in the proenzyme, a fully cobalt-substituted proenzyme was prepared by in vivo metal replacement. The absorbance features of dicobalt prostrom255 were consistent with metal coordination by the single cysteine present in the propeptide, although the data do not allow assignment to a particular zinc site.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Temporal and quantitative analysis of myogenic regulatory and growth factor gene expression in the developing mouse embryo.

Using a reverse transcription/polymerase chain reaction method, the temporal pattern of expression of the myogenic regulatory genes (myf5, myogenin, MRF4, myo D) was quantitated in developing mouse muscle (whole embryo: 6.5 to 12.5 days postcoitum (dpc); front limb buds: 9.5 to 12.5 dpc; hind limb buds: 11.5 to 14.5 dpc) and related to expression of TGF-beta 1, b-FGF, IGF-I, and IGF-II. Myf5 was the first myogenic regulatory factor to appear in both the whole embryo and front limb bud, with expression evident 7.5 and 9.5 dpc, respectively. A transient peak of MRF4 expression occurred 10.5 dpc in both the whole embryo and the front limb bud. Myogenin and myo D expression in the whole embryo was detected 8.5 and 9.5 dpc, respectively. In the front limb bud myogenin and myo D expression was not detected until 10.5 dpc. In the hind limb bud myf5, myogenin, and MRF4 expression was detected 11.5 dpc. Myo D expression was not detected until 12.5 dpc. With respect to growth factor expression, in the front limb bud TGF-beta 1, IGF-I, and IGF-II were evident 9.5 dpc, while bFGF was not detected until 10.5 dpc. In the hind limb bud TGF-beta 1, bFGF, IGF-I, and IGF-II expression was detected 11.5 dpc. These results show that in both the whole embryo and limb buds, all four myogenic regulatory factors are involved in the initiation of the myogenic program. We also show myf5 expression in the 9.5-dpc front limb bud, suggesting its expression in the somite-derived migrating muscle precursor cells. Correlations between growth factor-mediated myoblast proliferation and myogenic differentiation are discussed.

Animals↗
PubMed1992

Quantitative characterization of beta-adrenergic receptor subtypes in porcine adipocytes.

1. Two populations of beta-adrenergic receptor (beta AR) subtypes and their proportions were characterized in adipocytes isolated from subcutaneous adipose tissue of castrated male crossbred pigs (60-85 kg). 2. Specific binding of the radioligand 125I-iodopindolol (IPIN) to crude plasma membranes (70-90% of total binding) reached equilibrium conditions in 30 min (38 degrees C), was tissue concentration-dependent, stereospecific and saturable (bmax = 168 +/- 5.8 fmol/mg protein). 3. Displacement curves by ICI 89,406 were best-fit by a two site model (P less than 0.01) that indicated the presence of two receptor populations and selectivity of IPIN for the beta 2AR subtype. 4. Forty-five percent of the receptors had a high affinity for ICI 89,406, Ki = 2.27 +/- 0.68 nM and were classified as beta 1AR.

Adipose Tissue↗
PubMed1992

The focused physical examination. Should checkups be tailor-made?

The "complete physical examination" taught in medical schools is not always the best approach to clinical assessment of asymptomatic adults. The authors of this article review the controversy surrounding the utility of routine physical examination, advocating evolution in medical practice from use of the complete physical examination toward the focused physical examination.

Aged↗
PubMed1992

Effect of metoclopramide on luteinizing hormone secretion in postpartum anestrous cows.

The effect of metoclopramide (MC), a dopamine antagonist on luteinizing hormone (LH), was examined in anestrous primaparous cows. Metoclopramide has been found to be beneficial in overcoming fescue toxicosis; increasing LH secretion stimulates return to ovulatory function after parturition. Consequently, if MC had negative effect on LH secretion, it would indicate that administration of MC to reproducing animals might be limited. Of 14 postpartum (47 to 66 days) cows, 7 were given MC (4 mg/kg of body weight, IV), and 7 served as controls. Blood was obtained via jugular cannulas at 15-minute intervals for 8 hours; MC was given at the end of the first hour, and gonadotropin-releasing hormone (GnRH, 7 mg/kg), was given IV at the end of hour 7 as a challenge stimulus for LH secretion. Prior to GnRH administration, MC did not have significant effect on LH secretion, as judged by mean serum LH concentration, LH pulse frequency, and LH pulse amplitude. Administration of MC resulted in greater (P less than 0.05) LH response to GnRH, indicating enhanced secretory ability when the pituitary gland was challenged. Serum prolactin concentration was increased (P less than 0.01) by MC administration. Therefore, MC did not have adverse effect on LH secretion in postpartum cows.

Anestrus↗
PubMed1991

Preventive medicine in primary care. Moving from theory to practice.

Primary care physicians are in a unique position to offer preventive services. They have access to patients when intervention may be most successful, and they see most patients over a long period, which allows for adequate follow-up. The challenges are choosing the most effective interventions and organizing records and office staff to facilitate delivery of preventive services. Preventive medicine may not be as dramatic or as immediately successful as curative medicine, but it can have a tremendous long-term impact on health and well-being.

Humans↗
PubMed1990

Identification and characterization of a target antigen of a monoclonal antibody directed against Eimeria tenella merozoites.

Monoclonal antibodies (Mab) were produced against Eimeria tenella merozoites. A single Mab, LPMC-61, was selected because of its ability to bind to merozoites by indirect immunofluorescence assay (IFA) and to inhibit in vitro sporozoite development. Mab LPMC-61 reacts with an approx. 10-12-kDa merozoite polypeptide in reduced SDS-PAGE, but with an approx. 80-kDa protein in non-reduced SDS-PAGE. The monoclonal recognizes similarly sized polypeptides in E. tenella sporozoites, oocysts and schizonts. A partial cDNA (LPMC-61f) encoding the LPMC-61 antigen was identified from an E. tenella sporozoite cDNA library in bacteriophage lambda gt11. In addition to Mab LPMC-61, the recombinant beta-galactosidase/LPMC-61f fusion protein is recognized by hyperimmune rabbit anti-E. tenella sporozoite serum, rabbit anti-E. tenella merozoite serum, and E. tenella-infected and immune chicken sera. DNA sequencing of LPMC-61f cDNA showed that the putative protein has an unusual tandem, non-perfect repeated sequence, with glutamine comprising about 48% of the predicted amino acids. A hydropathicity plot of the predicted amino acid sequence shows a central hydrophilic region, consisting of the repeated sequences, surrounded by hydrophobic regions on both sides. Since the merozoite stage of avian Eimeria has been implicated in the induction of a protective immune response in chickens, LPMC-61 may be an important immunogen for use as a vaccine against E. tenella.

Amino Acid Sequence↗
PubMed1990

Legal review: informed consent--a shift from paternalism to self-determination?

This shift from a paternalistic standard for determining how much information should be disclosed to a person to a standard that values the self-determination of a person is consistent with the philosophical change in decision-making in a variety of areas of health care. Haber begins his article with a discussion of the psychiatry profession's proposed change in terminology from "patient" to "client." He argues that such a change would be more than semantic: It would serve the moral purpose of increasing such a person's autonomy. The right of patients to see their own medical records was formally recognized as part of the Patient's Bill of Rights in 1972 and has since been recognized by courts and incorporated into many state statutes. Likewise, the refusal of medical treatment has become a right more commonly recognized by the law throughout the 1970s and 1980s. For example, "living wills" are now a common vehicle for patients to express their views regarding the right to refuse treatment. Courts have recognized this right in cases of Jehovah's Witnesses refusing transfusions, the right to have life-sustaining procedures discontinued, and the restrictive involuntary commitment statutes that arose in the 1970s. Both the risks and benefits of medical treatments have increased with the forward march of technology. Patients have the right to choose to participate with their physicians in their own health care decision making; the trend toward the reasonable patient standard in medical malpractice suits that relied on negligent failure to obtain informed consent reflects a recognition of that right.

Decision Making↗
PubMed1989

Analytical determination of methylated histidine in proteins: actin methylation.

The methylation of histidine in actin from various muscle and nonmuscle sources has been studied by formation of phenylthiocarbamyl derivatives and subsequent reverse-phase high-pressure liquid chromatographic separation and analysis of actin hydrolyzates. All the actin species examined were found to contain 3-methylhistidine. This method has also been used in assays for the enzyme(s) responsible for methylation of rabbit skeletal muscle actin and to investigate the formation of other methylated residues in vitro. 3-Methyl-histidine is the major methylation product in this in vitro reaction.

Actins↗
PubMed1988

How illness presents: a study in the People's Republic of China.

Twenty-six patients were interviewed in five clinics at the Hunan Medical School in the People's Republic of China to assess the degree to which patients presenting with medical problems had primarily underlying psychological and social concerns. Patients in all five clinics (paediatrics, internal medicine, otolaryngology, urology and gynaecology) demonstrated a high degree of non-medical concerns. Fear of cancer was common. Many patients mentioned concerns about their children, sexual problems, or other family problems. Both patients and physicians seemed to be comfortable discussing the patients' personal problems and concerns. A medical presentation of psychosocial concerns was as common in China as it is in the United States.

Adolescent↗
PubMed1988

A psychosocial description of a select group of infertile couples.

Increasing attention in the literature has focused on the relationship between psychosocial factors and infertility. This study presents a psychosocial profile of infertile couples over a two-year period. During this period, psychosocial data including life change, social support, and personality traits were obtained prospectively from 134 individuals participating in the In Vitro Fertilization Program of the Jones Institute of Reproductive Medicine at the Eastern Virginia Medical School. Instruments utilized included the Life Experiences Survey, the Family APGAR, the Friends APGAR, the Multidimensional Health Locus of Control, and the Eysenck Personality Inventory. Despite the presumed adverse psychological influence of their infertility, Life Experience Survey scores for both men and women did not differ significantly from normative data. Family APGAR scores indicated a high degree of satisfaction with family function. Friends APGAR scores were somewhat lower than normative data. The Multidimensional Health Locus of Control, a measure of perception regarding factors influencing health outcomes, was unremarkable. The Eysenck Personality Inventory revealed a lower score on the neuroticism scale for the men. These psychosocial results were surprisingly normal.

Adult↗
PubMed1988

Glycemic control: arguments for and against.

There is substantial evidence that hyperglycemia does play a role in the development of long-term complications, although a genetic predisposition to these complications seems to be important. Also the literature seems to suggest that the degree of hyperglycemia correlates well with both the severity and incidence of long-term complications. However, looking at recent studies in the attempt to answer the question of "can we prevent or minimize complications," we must conclude that there is no definitive evidence that the typical long-term complications of microvascular or macrovascular disease can be prevented with tight control. Hopefully, the current study under way at the NIH will help clarify this issue. It seems likely after reviewing all the evidence that future studies will show tight control to be beneficial. The clinician must weigh the costs of tight control against the potential benefits, particularly in the type II diabetic. It seems prudent to strive for the best control that can be achieved within the confines of the patient's resources, to pay meticulous attention to all factors contributing to complications, such as hypertension and smoking, and to avoid subjecting the patient to undue risks.

Blood Glucose↗
PubMed1987

Effect of ionophorous anticoccidials on invasion and development of Eimeria: comparison of sensitive and resistant isolates and correlation with drug uptake.

Prophylactic levels of three ionophorous antibiotics, monensin, salinomycin, and lasalocid, were administered to groups of chickens and turkeys. All three ionophores markedly inhibited invasion of cecal tissues by sporozoites of ionophore-sensitive (IS) Eimeria tenella. Monensin and salinomycin also reduced invasion in turkeys by sporozoites of E. adenoeides, but lasalocid only minimally inhibited invasion. Invasion of ceca of monensin-medicated chickens was significantly greater by sporozoites of ionophore-resistant (IR) E. tenella than of the IS isolate. Concomitant experiments showed significant differences in [14C]monensin accumulation among IS and IR isolates of E. tenella. The decreased uptake of monensin by the IR isolates appeared to be accompanied by a decrease in responsiveness to the activity of monensin as well as to two other ionophores, salinomycin and narasin in cell culture. The amount of monensin, salinomycin or narasin required to inhibit development of E. tenella by 50% was 20 to 40 times higher for the IR isolates than for the IS ones. Collectively, the data suggest that differences in ionophore accumulation by IS and IR isolates of E. tenella might reflect differences in membrane chemistry and that these differences are responsible for the expressions of resistance that were observed in these studies. This expression of resistance appears to be common to all ionophores tested.

Animals↗