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Biomedical subjects

D F Jones

Publications and source records attributed to D F Jones.

At least 19 recordsLinked to original sources
PubMed1998

Secretory and cytosolic phospholipases A2 are activated during TNF priming of human neutrophils.

Cytokines alter neutrophil (PMN) function during inflammation, and Tumor Necrosis Factor (TNF) in vitro primes PMN such that receptor-mediated stimulation causes markedly enhanced release of arachidonic acid. We hypothesized that two Ca(2+)-dependent PLA2's in PMN might be activated during priming of the cell, thus affecting arachidonate release. A low molecular weight, secretory PLA2 was identified by enzymatic activity in the cell free supernates of primed or stimulated PMN, and in PMN disrupted by nitrogen cavitation. The enzymatic activity was calcium-dependent, acid stable, destroyed by dithiothreitol, and blocked by anti-sPLA2 antibodies. TNF caused secretion of sPLA2 and also caused an increase in cell-associated sPLA2 enzymatic activity. Activation and release were maximal with fMLP stimulation of TNF-primed PMN. Neutrophils also contained a cytosolic PLA2 (cPLA2) characterized by enzymatic activity which was calcium dependent, enhanced by dithiothreitol, and blocked by anti-cPLA2 antibody. TNF caused a doubling of cPLA2 enzymatic activity which was associated with phosphorylation of the enzyme as judged by a migration shift on Western blots. Thus, TNF priming of human PMN caused marked increase in fMLP stimulated AA release in parallel to enhanced activity of two different PLA2's.

Arachidonic Acid↗
PubMed1998

Effects of concentrations of peptides on microbial metabolism in continuous culture.

Effects of peptide concentrations on microbial metabolism were investigated using a basal diet in which peptides replaced urea as a N source at levels of 0, 10, 20, and 30% of total N. The basal diet contained 17.8% CP and 46% nonstructural carbohydrates. Each diet was provided to continuous cultures of rumen contents operating at liquid and solids flow rates of 12 and 4.5%/h, respectively. Production of microbial CP and digestion of DM and protein were affected quadratically by peptide addition, with the highest values for each variable on the diet containing 10% peptides. Fiber digestion decreased linearly with peptide addition. The depressed fiber digestion and microbial CP production at peptide concentrations > 10% seemed related to a linear decrease in ammonia concentration in the fermenters as peptide levels increased. Peptide-amino acid N recovered in the supernatant fluid did not increase with increasing peptides, because peptide uptake by the microbes increased as peptide concentrations increased. Even though the efficiency of conversion of peptide N to microbial CP increased with increasing peptides, there was no change in grams of microbial N produced per kilogram of OMD. We suggest that in diets high in nonstructural carbohydrates, excessive peptides can depress protein digestion and ammonia concentrations, resulting in decreased OMD, fiber digestion, and total microbial CP production.

Amino Acids↗
PubMed1994

Endobronchial needle aspiration in the diagnosis of small-cell carcinoma.

Endobronchial biopsy specimens of small-cell carcinoma often exhibit extensive crush artifact that precludes definitive diagnosis. Occasionally, cytologic study from the brushings and washings is also nondiagnostic, contributing to the frustration of the bronchoscopist. We reviewed our experience with this problem over the past 4 years. We identified five cases in which an endobronchial needle aspirate proved critical in establishing the diagnosis of small-cell carcinoma. We believe endobronchial needle aspiration is a valuable adjunct in the diagnosis of endobronchial small-cell carcinoma.

Aged↗
PubMed1994

Complete endobronchial occlusion by Kaposi's sarcoma in the absence of cutaneous involvement.

Bronchopulmonary Kaposi's sarcoma (KS) occurs in 20 percent of AIDS patients with cutaneous involvement; however, complete endobronchial occlusion is uncommon. Moreover, bronchopulmonary KS is infrequent in the absence of cutaneous manifestations. We report a case of documented complete endobronchial obstruction by KS without cutaneous involvement.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Identification and characterization of a gene activated by the deformed homeoprotein.

In Drosophila, the homeotic genes encode transcription factors which control segment identity during embryogenesis by specifying the appropriate set of 'target' genes necessary to produce the individual segmental characteristics. Though we know much about the homeotic genes and the proteins they encode, we know little of their targets. Here we identify and characterize one such target gene, a gene activated by the product of the homeotic gene Deformed. DNA binding assays and expression of reporter gene constructs indicate that activation of this gene requires a direct interaction between the Deformed protein and an upstream enhancer element at this target gene. However, although Deformed is required to activate this gene in cells of the maxillary segment, ectopically expressed Deformed does not activate the gene in other regions of the embryo. We conclude from this and other observations that additional factors may be required to activate the target gene, and, therefore, Deformed may participate in either a combinatorial or hierarchical activation signal in the maxillary cells. This newly identified gene encodes a novel protein of unknown function, though proteins with similar amino acid composition have been found. The pattern of transcript accumulation during embryogenesis indicates that this gene may be regulated by other homeoproteins in addition to Deformed.

Amino Acid Sequence↗
PubMed1992

Taking it to the streets. Helmet use and bicycle safety as components of inner-city youth development.

A three-week bicycle safety module (BSM) featuring helmet use was developed for an inner-city, comprehensive youth development program in East Wheeling, West Virginia. Prior to BSM intervention, no helmet use had been observed in the test neighborhood. After a three-week program focusing on safety behaviors and helmet use, students demonstrated significant improvements in knowledge, a positive relationship between skill and knowledge, and nearly 100 percent helmet usage rates. Unfortunately, neighborhood helmet use rates fell to nearly zero after the summer camp was over. The data suggest that helmet use and improved knowledge and skills could become the norm in an inner-city day-camp context, but periodic, model-oriented reinforcement of the BSM is recommended for maintenance of observed knowledge and usage improvements.

Adolescent↗
PubMed1990

Felodipine-ER once daily as monotherapy in hypertension.

One hundred and one hypertensive patients [diastolic pressure (dBP) 95-110 mm Hg after greater than or equal to 6 weeks with no antihypertensive therapy] were randomized to receive, double-blind, felodipine-ER 5 mg once daily (n = 49) or placebo (n = 52) for 2 weeks. Twenty-four hours post-dose, felodipine-ER 5 mg o.m. reduced dBP by a mean of 11 mm Hg; in contrast, dBP fell in the placebo group by 3 mm Hg (p less than 0.001). If the target dBP of less than or equal to 90 mm Hg was not attained at 2 weeks, the dose of felodipine-ER (or placebo) was doubled; if the target was not attained after a further 2 weeks, the doses were doubled again, to 20 mg felodipine-ER or placebo. If the target was achieved after 2 or 4 weeks, patients remained on that dose; the double-blind period for all patients was 6 weeks. After 6 weeks, the mean reduction in dBP in the felodipine-ER group was 14 mm Hg, significantly (p less than 0.001) greater than in the placebo group (8 mm Hg). Blood pressure "control" was defined prospectively as a seated dBP less than or equal to 90 mm Hg: after 6 weeks, 67% of patients receiving felodipine-ER compared with 27% on placebo had a controlled blood pressure (p less than 0.001). The figures after 2 weeks were 45% on 5 mg felodipine-ER and 21% on placebo (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1983

Baroreflex effects of althesin infusions to supplement nitrous oxide anaesthesia in man.

The effects on baroreflex control of heart rate, of two infusion rates of Althesin (18 and 36 micrograms kg-1 min-1 as total steroid) to supplement 66% nitrous oxide in oxygen anaesthesia, have been studied in six younger (mean age 35.5 yr) and six older (mean age 61.0 yr) patients. Steady-state anaesthesia at both infusion rates was associated with diminished baroreflex sensitivity and resetting of the reflex to allow lower arterial pressures to be maintained without tachycardia.

Adult↗
PubMed1982

Recovery from day-case anaesthesia: comparison of a further four techniques including use of the new induction agent diprivan.

Eighty unpremedicated patients received thiopentone and halothane, propanidid and fentanyl, diprivan (ICI 35 868) alone, or diprivan and fentanyl, each supplementing 66% nitrous oxide in oxygen. Diprivan alone, or in combination with fentanyl, resulted in a more rapid awakening than thiopentone and halothane, and significantly shorter recovery times than both thiopentone and halothane and propranidid and fentanyl. Administration of fentanyl with diprivan significantly reduced the total dose of the latter and all indices of recovery. Propanidid and fentanyl did not produce shorter overall recovery times than thiopentone and halothane but nausea and vomiting after operation were significantly increased when compared with the other techniques.

Adolescent↗
PubMed1980

Postoperative convulsions due to iophendylate (Myodil). Report of a case and review of the causes of postoperative convulsions.

A previously fit 58-year-old man underwent lumbar laminectomy following a myelogram. Postoperatively convulsions occurred. He was successfully treated and made a complete recovery. Large quantities of intracranial iophendylate (Myodil) were seen on postoperative skull X-rays. In the absence of other likely causes, a diagnosis of iophendylate-induced encephalopathy was made. A review of the aetiology of convulsions in the intra- and postoperative period is presented.

Anesthetics↗
PubMed1975

Industrial survey of lost time injuries.

An attempt to discover factors affecting lost time injuries under varying government programs involved visits to a sampling of industries in six provinces and six states. The resulting observations are used to illustrate some variables, many of which have previously been ignored, but which must be considered in any objective study of man at work.

Absenteeism↗