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Biomedical subjects

D Jones

Publications and source records attributed to D Jones.

At least 649 records · Page 36Linked to original sources
PubMed1986

The Biosynthesis of a Novel Nicotine Alkaloid in the Trichomes of Nicotiana stocktonii.

N-Hydroxyacylnornicotine, newly discovered from fresh plant tissue, was found entirely in the trichome exudate produced at the epidermis of the aerial part of Nicotiana stocktonii. Nicotine and nornicotine, but not N-hydroxyacylnornicotine, were present inside of the trichomes as well as other internal parts of the plant. Only nicotine was found in bleeding sap squeezed from cut roots or stems. Feeding of leaves with 2'-(14)C-labeled nicotine primarily yielded labeled nicotine, nornicotine, and N-hydroxyacylnornicotine. When similarly labeled nornicotine was fed to leaves as a precursor, a labeled N-hydroxyacylnornicotine was obtained, with a higher specific activity than with the [2'-(14)C]nicotine feeding. Based on these results, a synthesis route is suggested where nicotine is converted in the leaf to nornicotine, followed by trichome conversion of nornicotine to N-hydroxyacylnornicotine, and rapid secretion of this product.

Journal Article↗
PubMed1986

Rapid method for the detection of group B streptococci from human sources.

A modification of the classical CAMP test has been devised for the rapid detection of streptococci of serological Group B from human sources. The method was compared with detection based on the development of orange pigmented colonies on a starch-based medium and with detection by conventional methods. In a survey of vaginal carriage of Group B streptococci in parturient women, the modified CAMP test detected a carriage rate of 13.09%, the starch-based, pigment enhancing medium, 5.76% and the conventional methods, 8.38%. It proved to be particularly useful for detecting the organisms in the presence of other bacteria.

Ear↗
PubMed1986

Method for Assessing Heterogeneity in Turnover Rates within Microbial Communities.

A method is presented for determining both the average turnover rate and the standard deviation of the average turnover rate of the adenine nucleotide (AN) pool within a population of microorganisms. The method requires the calculation of the initial slope and curvature of a plot of AN specific activity versus time following the introduction of [H]adenine. An analysis of noise-corrupted data indicated that the method is capable of detecting a lack of uniformity in the turnover rate when the coefficient of variation of the turnover rate exceeds 39%. An analysis of field data revealed a significant lack of uniformity in the turnover rates of microbial communities in a marine sediment sample and freshwater pond but no significant nonuniformity in the turnover rates of microbial communities in a seawater sample and in a second freshwater pond. Although the method has been applied only to the analysis of AN turnover rates, it is applicable to any intracellular pool for which a suitable radioactive precursor exists.

Journal Article↗
PubMed1986

Efficacy of combined treatment with oral and topical acyclovir in first episode genital herpes.

Fifty patients presenting with first episode genital herpes were randomly allocated to seven day treatment with either oral acyclovir plus 5% acyclovir cream or oral acyclovir plus matching placebo cream. Combined treatment with oral and topical acyclovir was associated with a shorter duration of itching in women alone (p = 0.04) but gave no clinical relief of other symptoms, the time to healing of lesions, or the subsequent recurrence rate. Concomitant topical treatment with 5% acyclovir cream confers no advantages on patients who receive oral acyclovir.

Acyclovir↗
PubMed1986

Hormonal regulation of Na+-K+-ATPase in cultured epithelial cells.

Aldosterone and insulin stimulate Na+ transport through mechanisms involving protein synthesis. Na+-K+-ATPase has been implicated in the action of both hormones. We examined the effect of aldosterone and insulin on Na+-K+-ATPase in epithelial cells in culture derived from toad urinary bladder (TB6C) and toad kidney (A6). Aldosterone, but not insulin, increases short-circuit current (ISC) in TB6C cells. Aldosterone increases Na+-K+-ATPase activity after 18 h of incubation, but no effect can be seen at 3 and 6 h. Amiloride, which inhibits aldosterone-induced increases in ISC, has no effect on either basal or aldosterone stimulated enzyme activity. Both aldosterone and insulin increase ISC in A6 cells and when added together are synergistic. Aldosterone stimulates enzyme activity in A6 cells, but insulin alone has no effect. However, aldosterone and insulin together stimulate enzyme activity more than aldosterone alone. It appears that stimulation of Na+-K+-ATPase activity is involved in aldosterone action in both cell lines but does not appear to be due to increased Na+ entry, since enhanced enzyme activity is not inhibited by amiloride. In contrast, insulin alone has no direct effect on Na+-K+-ATPase, although the increased enzyme activity following both agents in combination may explain their synergism on ISC.

Aldosterone↗
PubMed1986

Prophylaxis against herpes labialis with acyclovir cream--a placebo-controlled study.

Patients with 6 or more recurrences per year of herpes labialis were entered into a randomized, double-blind, placebo-controlled, crossover study. During the trial, they applied acyclovir cream for 16 weeks and placebo cream for 16 weeks to all previously affected areas 4 times per day, and were subsequently observed for a further 16 weeks with no treatment. Results from the 23 evaluable cases showed that although recurrences did occur whilst on acyclovir treatment, patients suffered from significantly fewer days of disease and significantly fewer attacks of cold sores when compared with placebo.

Acyclovir↗
PubMed1986

Kinetics of prostaglandin E2 and thromboxane A2 synthesis and suppression of PHA-stimulated peripheral blood mononuclear leucocytes.

The immunomodulatory effects of thromboxane A2 and prostaglandin E2 on peripheral blood mononuclear leucocytes stimulated with PHA in vitro, and the relationship of this to the time-course of their synthesis in culture, were investigated using prostaglandin E2, a thromboxane A2 synthesis inhibitor (UK37248), a thromboxane A2 mimic (U46619) and a thromboxane A2 receptor blocker (EP045). The inhibitory effect of prostaglandin E2 on PHA-induced human peripheral blood mononuclear leucocyte proliferation diminishes if the addition of PGE2 is delayed. If added 4 hr after a maximum concentration of PHA (5 micrograms/ml), the effect of PGE2 was reduced by 60%. If a submaximal concentration of PHA (1 microgram/ml) was used, the effect of PGE2 was not reduced if added 4 hr later but fell by about 60% after 16 hr. UK37248 moderately inhibited PHA-induced activation while substantially inhibiting thromboxane A2 synthesis and simultaneously enhancing PGE2 synthesis. The enhanced accumulation of PGE2 occurs while sensitivity to PGE2 is dropping. U46619, exogenously applied as a thromboxane A2 mimic, inhibited PHA-induced activation at concentrations that did not significantly alter PGE2 synthesis. EP045, which may modulate the effects of endogenous thromboxane A2 by blocking receptors, did not alter PHA-induced activation. We conclude that thromboxane A2 may have a role in inhibiting PHA-induced activation on the basis of the effect of U46619. However, this study highlights difficulties in utilizing prostaglandin and thromboxane receptor and synthesis inhibitors to examine their endogenous role in the modulation of mitogen-induced activation in vitro. If sensitivity to the purported endogenous substance is limited to the early stages of culture and if only low levels are synthesized at this early stage, then blocking drugs would have little effect.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1986

Outcome of colectomy and ileorectal anastomosis in Crohn's disease.

The outcome of 42 patients undergoing colectomy and ileorectal anastomosis (IRA) for Crohn's colitis, which largely spared the rectum, was studied. Operative mortality was 7% (3 patients) and each patient died as a result of anastomotic breakdown. The overall incidence of anastomotic breakdown was 16.7% (7 patients). This complication was higher following a primary anastomosis (6 of 26 patients: 23%), compared with a delayed anastomosis (1 of 16 patients: 6.3%). Patients were followed up for a median of 7 years (range 3 months-20 years) and questioned with regard to their quality of life. Cumulative reoperation rates at 5 years were 55%, and at 10 years were 74%. Most patients assessed following surgery enjoyed an unrestricted social life and none would contemplate the alternative of an ileostomy. The study suggests that despite the high incidence of recurrence, the quality of life following surgery can be good and supports the view that colectomy and ileorectal anastomosis can be used as an alternative to proctocolectomy in the treatment of Crohn's colitis for a select group of patients.

Colectomy↗
PubMed1986

Medication education program in an inpatient geriatric rehabilitation unit.

All patients admitted during a 6-month period to an inpatient geriatric rehabilitation unit were started on a medication education program incorporated into the rehabilitation program and utilizing existing staff. Patients were evaluated at admission, discharge, 90-day, and 1 year follow-up, using an 8-point medication knowledge scale. Of the 62 patients included in this study, at discharge 35 (group I, mean age 75.9) knew their medications and went home, 10 (group II, mean age 76.8) did not know their medications and went home, and 17 (group III, mean age 79.3) did not go home, whether they knew their medications or not. Mean length of stay (days) was: group I-30.9; group II-38.9; group III-33.3. This study describes a program for teaching an inpatient geriatric age group population self-medication management.

Aged↗
PubMed1985

Possible mechanism of the synergistic effect of heparin and dihydroergotamine.

A combination of heparin and dihydroergotamine mesylate (Heparin-Dihydergot) has been shown to be more effective than either of these drugs alone in preventing postoperative venous thromboembolism. The possible mechanism for the synergistic effect of heparin and dihydroergotamine was assessed. Phlebograms obtained after administration of 0.5 mg of dihydroergotamine showed marked constriction of the tibial and soleal veins with a significant reduction in the mean diameter of the femoral vein. The effect on the coagulation mechanism was assessed in 28 patients. Blood samples were withdrawn from the femoral vein during varicose vein operations. A significant difference was observed in antithrombin III activity, kaolin-cephalin clotting time, beta-thromboglobulin, and fibrino-peptide levels between the control, dihydroergotamine, heparin, and the combination groups.

Antithrombin III↗
PubMed1985

Rearrangement of the T-cell-receptor beta-chain gene in the diagnosis of lymphoproliferative disorders.

The arrangement of the T-cell-receptor and immunoglobulin genes has been analysed in 77 cases of lymphoproliferative disorder. All 6 T-cell leukaemias and 16 of 19 T-cell lymphomas showed rearrangement of the gene coding for the beta chain of the T-cell receptor, associated in all cases with a germline arrangement of the immunoglobulin genes. All 36 B-cell leukaemias and all 16 B-cell lymphomas showed rearrangement of immunoglobulin genes; the T-cell-receptor gene was in the germline configuration in most of these cases but showed a rearranged pattern in 3 cases (2 chronic lymphatic leukaemias and 1 immunoblastic lymphoma). The combined use of T-cell-receptor and immunoglobulin gene probes promises to be a valuable means of identifying and classifying T-cell neoplasms.

Autoradiography↗
PubMed1985

Heterogeneity of T-cell beta-chain gene rearrangements in human leukaemias and lymphomas.

The state of T-cell receptor beta-chain gene rearrangement in human T-cell leukaemias has been analysed. All forms of leukaemia tested (T-CLL, ALL, PLL, Sezary syndrome and ATL) exhibit rearrangements of C beta genes confirming the clonality of these neoplasias. However we find no evidence for common gene rearrangements nor for restricted rearrangement patterns within this type of neoplasia. We find evidence of T-cells with C beta 1 and C beta 2 rearrangements, sometimes associated with Igh JH rearrangements, but several cases of T-cell leukaemia with a marker inversion of chromosome 14 (q11;q32) do not have Igh JH rearrangements. The results suggest that TCR beta gene rearrangement occurs early in T-cell ontogeny but that this rearrangement is most often irrelevant to leukaemogenesis.

Cell Line↗
PubMed1985

Parasite regulation of host insect metamorphosis: a new form of regulation in pseudoparasitized larvae of Trichoplusia ni.

When eggs of Trichoplusia ni (lepidoptera) are stung by a parasitic wasp, Chelonus sp., the developing host larvae precociously initiate metamorphosis ten days later. Precocious initiation of metamorphosis occurs even in 'pseudoparasitized' stung hosts which contain no living parasites at the time of symptoms of host regulation by the parasite. In feeding, penultimate instar, pseudoparasitized hosts, the corpora allata activity, hemolymph juvenile hormone esterase activity, in vivo rates of juvenile hormone metabolism and changes in hemolymph protein composition all follow the pattern of the normal last instar. This and other evidence suggests the entire developmental pattern of the last larval instar is precociously expressed in penultimate instar, pseudoparasitized hosts. The cause of precocious expression of the developmental program leading to metamorphosis is a significant decrease in the critical size parameter that, in normal larvae, signals attainment of the last instar. The induction, in preultimate instar larvae, of the entire feeding stage developmental program leading to metamorphic commitment, using either biochemical, surgical or parasitic experimental probes, has not been previously reported. The results have important implications for the study of host-parasite endocrine interaction, of normal insect metamorphosis and even of human puberty.

Animals↗
PubMed1985

Cholinergic REM induction response: separation of anxiety and depression.

Five groups of subjects underwent EEG sleep recordings, arecoline rapid eye movement (REM) induction response testing, and Schedule for Affective Disorders and Schizophrenia (SADS) interview. Group I: 20 patients with primary major depressive disorder (MDD) (endogenous) without any coexisting anxiety disorder; Group II: 19 primary MDD (endogenous) patients with secondary panic, GAD, or phobic disorders; Group III: 18 patients with primary anxiety disorder without coexisting MDD; Group IV: 14 patients with primary anxiety plus secondary MDD; Group V: 26 normal controls. Modified Research Diagnostic Criteria (RDC) were used for diagnosis, based on the SADS interview. There was considerable overlap of SADS scaled scores between patient groups, which is consistent with a heterogeneous clinical presentation of depressive and anxiety states. REM latency was significantly shorter in patients with primary MDD (without anxiety) as compared with that in patients with primary anxiety (no MDD) and normals. Arecoline REM induction response time was significantly shorter in both primary affective groups (I and II) as compared with primary anxiety (no MDD) patients and normal controls. REM latency and arecoline REM induction time was not significantly different between the primary anxiety groups (III and IV) and normals. The study highlights the use of biological markers in differentiating between clinical syndromes confounded by mixed or overlapping phenomenology.

Adult↗