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Biomedical subjects

D C Jones

Publications and source records attributed to D C Jones.

At least 73 records · Page 4Linked to original sources
PubMed1993

Metabolism and enantioselective pharmacokinetics of Casodex in man.

1. Five healthy male volunteers received a single oral dose (50 mg; 42 microCi) of 14C-Casodex, a racemic compound, which has its antiandrogen activity predominantly in R-Casodex, the (-)-enantiomer, with little activity in S-Casodex, the (+)-enantiomer. 2. Plasma concentrations of R-Casodex increased slowly in all subjects to reach a peak of 559-970 ng/ml between 15 and 48 h after dosing and, thereafter, declined monoexponentially with a mean half-life of 4.2 days. Plasma concentrations of S-Casodex rose rapidly to reach a peak of 32-66 ng/ml within the first 2-5 h, and then declined monoexponentially with a mean half-life of 19 h. Plasma concentrations of the racemate were in very good agreement with the sum of the enantiomer concentrations throughout the study and were very similar to concentrations of total radioactivity over the first 4 days. 3. About 80% of the radioactive dose was recovered in urine (35.8 +/- 1.7%; mean +/- SEM) and faeces (42.6 +/- 2.9%) during a total collection over 9 days; this incomplete recovery was consistent with the slow elimination of R-Casodex. 4. T.l.c. of urine extracts indicated extensive metabolism of Casodex to two polar metabolites identified as the glucuronide conjugates of Casodex and hydroxy-Casodex; almost no parent compound was observed. Virtually all of the Casodex glucuronide excreted in urine during the first 2 days was derived from S-Casodex, consistent with the relatively low plasma concentrations and rapid elimination of this enantiomer. 5. T.l.c. of faecal extracts showed the presence of both Casodex and hydroxy-Casodex; these may have been eliminated in bile as the glucuronide conjugates, with subsequent hydrolysis in the intestinal tract.

Administration, Oral↗
PubMed1993

Foot orthoses.

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Adult↗
PubMed1992

Seizures involving secondary sensory and related areas.

Five patients with seizures involving the secondary sensory and/or related areas (SSRA) are presented. Four of five experienced ictal numbness and/or tingling bilaterally and/or axially; this involved fingertips (three patients), lips (two), tongue (two), and was diffuse in one. The fifth patient experienced bilateral ictal pain. Associated ictal symptoms implicating adjacent regions appeared in all five patients, including contralateral clonic movements (two patients), hypersalivation (two), taste (one), vocalization (two), dysphagia (one), and contralateral sensory march (one). Two patients had ictal symptoms suggestive of adjacent temporal lobe involvement. By history, the SSRA was involved at seizure onset in four and by spread in one. All five patients had electroencephalogram (EEG) or subdural EEG supportive evidence of SSRA involvement: ictal (three) and interictal (three). Three patients had lesions in this area shown by magnetic resonance imaging or computerized tomography and all three had histologically proven glial tumours. Relevant experimental physiological and anatomical data are reviewed.

Adult↗
PubMed1992

Ehrlichia ewingii sp. nov., the etiologic agent of canine granulocytic ehrlichiosis.

The 16S rRNA gene was amplified, cloned, and sequenced from the blood of two dogs that were experimentally infected with the etiologic agent of canine granulocytic ehrlichiosis. The 16S rRNA sequence was found to be unique when it was compared with the sequences of other members of the genus Ehrlichia. The most closely related species were Ehrlichia canis (98.0% related) and the human ehrlichiosis agent (Ehrlichia chaffeensis) (98.1% related); all other species in the genus were found to be phylogenetically much more distant. Our results, coupled with previous serologic data, provide conclusive evidence that the canine granulocytic ehrlichiosis agent is a new species of the genus Ehrlichia that is related to, but is distinct from, E. canis and all other members of the genus. We propose the name Ehrlichia ewingii sp. nov.; the Stillwater strain is the type strain.

Animals↗
PubMed1992

Characterization of a novel Rochalimaea species, R. henselae sp. nov., isolated from blood of a febrile, human immunodeficiency virus-positive patient.

Isolation of a Rochalimaea-like organism from a febrile patient infected with human immunodeficiency virus was confirmed. Analysis of 16S rRNA gene sequences, together with polymerase chain reaction and restriction endonuclease length polymorphism analysis of a portion of the citrate synthase gene, demonstrated that the agent is closely related to members of the genus Rochalimaea and that the isolate is genotypically identical to the presumptive etiologic agent of bacillary angiomatosis. However, the same genotypic analyses readily differentiated the new isolate from isolates of other recognized Rochalimaea species as well as other genera of bacteria previously suggested as putative etiologic agents of bacillary angiomatosis and related syndromes. We propose that the novel species be referred to as Rochalimaea henselae sp. now.

Adult↗
PubMed1992

Parental drinking, parent-child communication, and social skills in young adults.

The goals of this study are to determine (1) if parent-child communication is associated with the level of alcoholic problems within the family and (2) if there is a relationship between problem drinking, family communication and the self-reported social skills of the young adult child. The self-reports of 338 students indicate that young adults who have memories of regular problem drinking within the family perceive less positive regard and a greater denial of or inattention to their feelings by the parents. Problem-drinking level interacted with either criticism or denial of feelings or emotional support to parents to predict primarily nonverbal social skills such as decreased emotional expressivity and increased sensitivity to the emotional cues of others. The results indicate that the effect of parental alcoholism on social skills of the young adult child must be considered in conjunction with specific types of family communication.

Adolescent↗
PubMed1991

Ehrlichia chaffeensis, a new species associated with human ehrlichiosis.

The bacterial 16S rRNA genes from blood samples of two patients with human ehrlichiosis and from an isolate recovered from one of the patients were amplified by using the polymerase chain reaction. The amplimers were then cloned and sequenced. The 16S rRNA gene sequence was also determined for Ehrlichia canis (two strains), E. equi, E. phagocytophila (two strains), and E. sennetsu (two strains). These sequences, along with a previously published 16S rRNA gene sequence of E. risticii, were compared. The 16S rRNA gene sequences were identical for all three sources of the human ehrlichiosis agent. The sequence comparisons indicate that the human ehrlichiosis agent is a new species most closely related to E. canis (98.2%) and more distantly related to other Ehrlichia spp. We propose that this species be named Ehrlichia chaffeensis sp. nov., with the Arkansas strain as the type strain.

Base Sequence↗
PubMed1991

Urinary calcium as an early marker for preeclampsia.

Women who develop preeclampsia during pregnancy excrete less calcium than healthy pregnant women. Whether this reduction in calcium excretion precedes or follows hypertension is unknown. We prospectively measured urinary calcium excretion in 103 consecutive nulliparous women at risk for preeclampsia and presenting for prenatal care before 24 weeks' gestation. Serial 24-hour urine specimens were obtained at 10-24 weeks, 25-32 weeks, and 33 weeks to term. After delivery, the charts were reviewed for the presence of preeclampsia and gestational hypertension. At the first collection, patients who later developed preeclampsia excreted less urinary calcium (169 +/- 30 mg/24 hours; mean +/- standard error of the mean) than those who remained normotensive (298 +/- 15 mg/24 hours) (P less than .05); this reduction persisted throughout gestation. Using a receiver operator curve, we calculated a predictive threshold calcium value for hypertension of 195 mg/24 hours. The difference in the incidence of preeclampsia between pregnant women with calcium excretion values at or below 195 mg/24 hours (87%, 95% confidence interval 52-98%) and those with values above that level (2%, confidence interval 0.3-8%) was highly significant (Fisher exact test, P less than .0001). The 95% lower limit of relative risk for preeclampsia in patients with a calcium excretion equal to or below 195 mg/24 hours in the first collection was 9.4. These observations suggest a pathophysiologic role for altered urinary calcium excretion in women with preeclampsia that may contribute to the early identification of patients at risk for this disease.

Adolescent↗
PubMed1990

Catabolism of 3-hydroxybenzoate by the gentisate pathway in Klebsiella pneumoniae M5a1.

Growth of Klebsiella pneumoniae M5a1 on 3-hydroxybenzoate leads to the induction of 3-hydroxybenzoate monooxygenase, 2,5-dihydroxybenzoate dioxygenase, maleylpyruvate isomerase and fumaryl-pyruvate hydrolase. Growth in the presence of 2,5-dihydroxybenzoate also induces all of these enzymes including the 3-hydroxybenzoate monooxygenase which is not required for 2,5-dihydroxybenzoate catabolism. Mutants defective in 3-hydroxybenzoate monooxygenase fail to grow on 3-hydroxybenzoate but grow normally on 2,5-dihydroxybenzoate. Mutants lacking maleylpyruvate isomerase fail to grow on 3-hydroxybenzoate and 2,5-dihydroxybenzoate. Both kinds of mutants grow normally on 3,4-dihydroxybenzoate. Mutants defective in maleylpyruvate isomerase accumulate maleylpyruvate when exposed to 3-hydroxybenzoate and growth is inhibited. Secondary mutants that have additionally lost 3-hydroxybenzoate monooxygenase are no longer inhibited by the presence of 3-hydroxybenzoate. The 3-hydroxybenzoate monooxygenase gene (mhbM) and the maleylpyruvate isomerase gene (mhbI) are 100% co-transducible by P1 phage.

Chromatography, Ion Exchange↗
PubMed1990

Adenoid cystic carcinoma of the palate in a 9-year-old boy.

Malignant tumors of salivary glands in children are extremely rare. A case of an adenoid cystic carcinoma affecting the palate in a 9-year-old child is described. This tumor has not previously been reported as affecting the minor salivary glands among patients in this age group.

Carcinoma, Adenoid Cystic↗
PubMed1990

Close friendships among senior adults.

The purpose of this research was to evaluate the relative contributions of personal, affective, and social exchange characteristics to satisfaction with the best friendship. Senior adults (N = 76) described and evaluated their best friendships in terms of positive and negative affect, equity, reciprocity of social support, and satisfaction. The individual's endorsement of communal and exchange orientations were included as personal characteristics. The study confirms that a communal orientation enhances satisfaction with a best friendship and that conflict and negativity detract from it. Social exchange characteristics were not related to friendship satisfaction. The need to reevaluate the role of social exchange in close relationships is discussed.

Affect↗
PubMed1990

A protective protein antigen of Rickettsia rickettsii has tandemly repeated, near-identical sequences.

The nucleotide sequence of a Rickettsia rickettsii gene that encodes a high-molecular-mass surface antigen (190 kilodaltons), which elicits protective immunity, was determined. The 6,747-nucleotide gene coded for a 2,249-amino-acid protein with a calculated molecular weight of 224,321. A 3.8-kilobase PstI fragment proximal to the 5' end of the gene was found to consist of 13 highly related tandem repeats which constituted over 40% of the coding region. The repeated sequences could be divided into either a 225-nucleotide, 75-amino-acid unit (type I) or a 216-nucleotide, 72-amino-acid unit (type II), with extensive homology between the two types of repeating units. The deduced amino acid sequence for these repeat units, overall, was slightly hydrophobic with short hydrophilic domains. The carboxy-terminal (nonrepetitive) portion of the deduced protein sequence was hydrophilic, with potential surface-exposed epitopes. The full-length reading frame was reconstructed in Escherichia coli, and transient expression of the 190-kilodalton antigen was demonstrated; however, the protein appeared to be severely degraded by proteases and was apparently toxic to E. coli. The conservation of this unique repetitive gene structure, coupled with results from previous reports showing the protective properties of the 190-kilodalton antigen, suggests that this protein plays an important role in the pathogenesis of and immunity to Rocky Mountain spotted fever.

Amino Acid Sequence↗
PubMed1990

Effect of angiotensin II infusion during normal pregnancy on flow velocity waveforms in the uteroplacental and umbilical circulations.

Women destined to develop preeclampsia show an increased systemic pressor response to infused angiotensin II, and the angiotensin sensitivity test has been accepted as an appropriate means of identifying these women. However, the effect of angiotensin II infusion on uteroplacental blood flow is unknown and may be deleterious. Patients undergoing angiotensin sensitivity tests as part of a protocol examining the effect of aspirin on the incidence of preeclampsia were studied with Doppler velocimetry performed before and during the angiotensin II infusion. Fetal well-being was documented with biophysical profiles performed before and after the infusions. Neither the systolic-diastolic ratios in the uterine and umbilical arteries nor the biophysical profile scores were altered significantly (P = .43, P = .23, Wilcoxon signed-rank median test, and P = .35, Fisher exact test, respectively). These findings suggest that the angiotensin sensitivity test does not increase resistance to flow in the uterine or umbilical circulation, and therefore may be used safely in screening for preeclampsia.

Adolescent↗
PubMed1988

Nitrous oxide contamination during out-patient cryosurgery.

Nitrous oxide concentrations have been measured spectrophotometrically in an out-patient clinic to assess pollution during simulated cryosurgery. Unacceptable levels, in excess of 2,000 ppm, were achieved during freezing and thawing and concentrations decreased only to 400 ppm when simple measures were taken to ventilate the clinic. The apparatus required a flow-rate of 11 l/min. It is concluded that scavenging apparatus should be used during cryosurgery with nitrous oxide if treatment is prolonged. Liquid nitrogen systems are preferable if excellent ventilation and scavenging apparatus are not available.

Air Pollutants↗
PubMed1988

Prevalence of atopy in a sickle-cell anemia population.

Contrary to reports in the literature, we found no statistical difference between the prevalence of atopic disorders (asthma, hayfever, and atopic dermatitis) in patients with sickle-cell anemia and their prevalence in nonsickle-cell reference populations. We examined this issue by determining the prevalence of atopy in a sickle-cell anemia population.

Anemia, Sickle Cell↗