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D L Smith

Publications and source records attributed to D L Smith.

At least 523 records · Page 29Linked to original sources
PubMedDate not supplied

Additional bioactive heptenes from Melodorum fruticosum.

Four additional new bioactive heptenes, melodorinol [2], homomelodienone [4], 7-hydroxy-6-hydromelodienone [5], and homoisomelodienone [7] have been isolated from Melodorum fruticosum. These compounds were slightly to significantly cytotoxic to human tumor cell lines. Their structures have been determined by comparison of their 1H-nmr, 13C-nmr, and mass spectral data with those of prototype compounds (acetylmelodorinol [1], melodienone 3, and isomelodienone [6]).

Alkenes↗
PubMedDate not supplied

Studies on the blood of a Dc(e) homozygote and her family.

It has been reported previously that genes that have been called Dc- represent a heterogeneous group and that some of them would better be described as Dc[e] and Dc(e). We have studied the blood of a black proposita and some of her family members and have concluded that she is homozygous for Dc(e). The form of Dc(e) present in this family makes all the Rh antigens of common occurrence for which we were able to test. In this respect, it differs markedly from another form of Dc(e), which is seen in individuals whose red cells lack a very common Rh antigen and who become immunized against that antigen. We suggest the term Dc(e)R17 for the gene present in the family studied; our results indicate that its products are: normal amounts of D, c, G, Hr0, and Rh29; reduced amounts of e and f; and markedly reduced amounts of hrS and hrB. The expression of some antigens encoded by Dc(e)R17 are quantitatively but not qualitatively different from the products of R0.

Blood Grouping and Crossmatching↗
PubMedDate not supplied

Detection of the source of recurrent Staphylococcus aureus bacteremia by ultrafast computerized tomography.

A patient with spina bifida secondary to an Arnold-Chiari deformity experienced seven episodes of sustained bacteremia due to Staphylococcus aureus over 2 years. Despite an extensive diagnostic evaluation the source of the recurrent bacteremia remained obscure. The patient's mother eventually recalled that a procedure for replacement of a ventriculoatrial shunt performed 16 years earlier had been complicated by retention of a shunt fragment in the bloodstream. Standard radiographic techniques failed to identify an intravascular foreign body; however, ultrafast computerized tomography of the heart demonstrated a density in the right atrium. Atriotomy was performed and a plastic catheter fragment was excised. Bacteremia has not recurred during a follow-up period of 24 months. Patients with recurrent unexplained bacteremia should be evaluated carefully for the presence of occult intravascular catheter fragments that may be retained after surgical procedures or intravascular instrumentation. Ultrafast computed tomographic scanning of the heart is a useful technique for detecting intracardiac catheter fragments.

Adolescent↗
PubMedDate not supplied

Characterization of the T, L, I, S, M and P cell surface (immobilization) antigens of Tetrahymena thermophila: molecular weights, isoforms, and cross-reactivity of antisera.

In the ciliate protist Tetrahymena thermophila the L, H, T, I, S, M and P cell surface proteins (immobilization antigens) are expressed under different conditions of temperature (L, H, T), culture media (I, S), and mutant genotype (M, P). Immunoblot and autoradiographic studies using antisera to purified protein show that the molecular weights of these proteins range from 25,000 to 59,000. The H, T, S, M and P antigens are recognized as single polypeptides, whereas L, I, and one allelic form of T each appear to consist of a family of polypeptides. Although antisera are specific in immobilization and immunofluorescence assays of surface protein in living cells, cross-reactivity is seen with denatured protein on immunoblots. It is hypothesized that the surface protein genes are organized into families of evolutionarily related isoloci.

Animals↗
PubMedDate not supplied

Exceptions to mutual exclusion among cell surface i-antigens of Tetrahymena thermophila during salt stress and stationary phase.

In ciliates, only one of the alternative forms of the immunodominant membrane glycoprotein usually coats the external surface of the cell. Such mutual exclusion is regulated at the pretranslational level by mechanisms that result in the expression of a single protein gene. In the holotrich Tetrahymena thermophila five alternative cell surface immobilization proteins (i-antigens) are expressed under different conditions of temperature (L, H, T) and culture media (I, S). Using polyclonal and monoclonal antibodies to these proteins and a cDNA probe derived from the SerH3 gene, we have reinvestigated expression of i-antigens in media supplemented with 0.2 M NaCl. We find that in addition to S, the H and L antigens are also present on the cell surface. While all three i-antigens may be simultaneously present on the cell surface, the combinations S/L and S/H are more frequent. Compared to cells expressing H and L singly, the level of H3 mRNA is diminished, and a subset of the L family of polypeptides is variably expressed. The expression of S begins within 30 min after transfer to NaCl-supplemented medium, while the expression of L begins three days to several weeks after transfer. When cells are transferred out of NaCl-supplemented medium, S is turned off within 24 h, and L is expressed for at least 1 wk prior to the return of full H expression. Although these differences in kinetics suggest differences in control mechanism(s), the absence of I and T on the surface of NaCl-grown cells suggests that there is also a common regulatory link among H, S and L.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Antiatherosclerotic effects of nicardipine and nifedipine in cholesterol-fed rabbits.

Dutch-belted rabbits fed a 2% cholesterol diet for 8 weeks developed atherosclerotic lesions that covered 37.2% +/- 3.5% of the aortic luminal surface. In samples of aortic arch, accumulation of cholesterol and triglyceride was also observed. Oral administration of nicardipine or nifedipine at dosages of 40 mg/kg twice daily for 8 weeks reduced plaque area by 49.2% and 58.7%, respectively. Nicardipine and nifedipine reduced cholesterol accumulation in the aortic arch by 74.5% and 69%, respectively. Triglyceride accumulation was totally abolished. Neither drug significantly altered cholesterol concentration of plasma low density lipoprotein or high density lipoprotein, although nicardipine produced a 42% reduction in cholesterol concentration of the d less than 1.006 g/ml fraction. The above results suggest potential therapeutic utility of nicardipine in atherosclerosis.

Animals↗
PubMedDate not supplied

Field penetration of arrays of compact applicators in localized hyperthermia.

The three-dimensional analysis of a range of new compact applicators indicates that there is an optimum operating frequency for maximum depth of field penetration and a given applicator size. The prospect of obtaining increased penetration depth by deploying more than one applicator is considered and assessed for an equi-phase array of compact applicators arranged symmetrically around a cylindrical shaped volume of uniform muscle phantom material; field penetration curves enable the maximum cross-section that can be heated to be assessed. Experiments at 200 MHz and results from a three-dimensional analysis demonstrate the usefulness of the assessment and establish that in multi-applicator configurations the field penetration decreases markedly for cross-sectional diameters in excess of 10 cm. However, the three-dimensional analysis for four applicators also shows that more uniform fields are obtained in the muscle phantom when it is surrounded by a low loss bolus region. In conclusion the clinical implications of the investigations are briefly discussed.

Humans↗
PubMedDate not supplied

A strategy to identify the learning needs of staff nurses.

Rapidly changing technology and the trend toward specialization make continuing education (CE) vital for today's nurses. Various methods to assess CE needs of nurses are described in the literature. This article outlines an assessment strategy implemented to determine staff nurses' perceptions of their learning needs. In addition, head nurses and clinical directors were surveyed regarding their perceptions of the staff nurses' learning needs. The chosen strategy used limited resources to contact a large number of nurses within a short time frame. Results indicated that the three groups surveyed perceived similar learning needs for staff nurses.

Education, Nursing, Continuing↗
PubMedDate not supplied

Information management: a long-term investment.

Conventional information processes are inadequate to meet today's health care demands. To allocate scarce resources, new approaches to information management are needed. This article explains how tapping the horizontal flow of information--across departments, services and programs--presents the greatest opportunities and challenges for health care management. New information infrastructures can integrate the entire health care system, and ultimately lead to enhanced affordability.

Canada↗