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M Jones

Publications and source records attributed to M Jones.

At least 739 records · Page 41Linked to original sources
PubMed1986

Optical depolarization changes in single, skinned muscle fibers. Evidence for cross-bridge involvement.

Optical ellipsometry studies of single, skinned muscle fibers conducted on the diffraction orders have yielded spectra that are sensitive to the state of the fiber. The linearly polarized light field vector becomes elliptically polarized as it passes through the fiber and may be collected at the diffraction orders. Fibers that have been subjected to extraction of myosin (0.6 M KCl) retain a weak diffraction pattern and exhibit a substantially decreased depolarization of incident linearly polarized light. A significant decrease in polarization is seen in skinned fibers that are subject to an increase in pH from 7.0 to 8.0. This increase in pH results in a decrease of approximately 30% in the depolarization angle of single fibers. The major decrease in depolarization angle that we observe at pH 8.0 is consistent with the notion that as cross-bridges move out from the shaft of the thick filament, their ability to cause depolarization of the incident linearly polarized light decreases. This interpretation is also consistent with the work of Ueno and Harrington where the decrease in the ability to cross-link S-1 and S-2 to the thick filament at pH 8.2 suggests cross-bridge movement away from the thick filament. A large decrease in birefringence, seen after treatment of skinned fibers with alpha-chymotrypsin, appears to be related to the breakdown of myosin into rod, S-1, heavy meromyosin, and light meromyosin.

Adenosine Triphosphate↗
PubMed1986

The in vivo malignant transformation of mouse fibroblasts in the presence of human tumour xenografts.

During the routine serial passage of over 30 human tumour xenografts in athymic (nu. nu.) mice over a period of 6 years the induction of murine fibrosarcomas at the site of transplantation has been observed on three occasions. In two cases it has been possible to follow the development of these tumours over successive transplant generations. These sarcomas had growth rates, tumour karyotypes and isoenzyme patterns which clearly distinguished them from the original human xenografts.

Animals↗
PubMed1986

The use of a birthroom: a randomized controlled trial comparing delivery with that in the labour ward.

A randomized controlled trial of two environments for delivery was conducted at Queen Charlotte's Maternity Hospital. A total of 253 parous women expecting to have a labour ward delivery were invited to participate in the trial but only 148 agreed. These women were randomly allocated to be delivered either with standard labour ward management (n = 72) or in the birthroom--a small bedroom decorated in a homely manner, without facilities for epidural analgesia or electronic fetal monitoring (n = 76). Eleven women in the birthroom group and 10 in the labour ward group withdrew from the trial before labour and four were transferred from the birthroom to the labour ward when in labour. A questionnaire sent in the postnatal period to the women who completed the trial was returned by 80%. In the birthroom group there was significantly (i) decreased admission-to-delivery interval (ii) less analgesia (iii) more freedom of movement (iv) less suturing (v) increased rooming-in. No difference was found in the assessment of difficulty of labour nor in the method of subsequent infant feeding.

Clinical Trials as Topic↗
PubMed1986

A study of anti-poly (ADP-ribose) antibodies and an anti-DNA antibody idiotype and other immunological abnormalities in lupus family members.

The genetic background of systemic lupus erythematosus (SLE) has been reexamined in a study of the serum of 31 lupus patients and 80 asymptomatic first degree relatives by measuring a common, cross reacting anti-DNA antibody idiotype designated 134, antibodies to poly(ADP-ribose), serum C3, circulating immune complexes, and antinuclear antibodies (ANA). Over 30% of the relatives had raised 134 and anti-poly(ADP-ribose) levels, and 9% had ANA titres greater than 1/20. In contrast, only one relative had a low serum C3 level. These results confirm that immunogenetic abnormalities associated with the production of autoantibodies and particular idiotypes must exist amongst lupus relatives as well as the patients. The production of autoantibodies, however, is not necessarily matched to the clinical expression of SLE.

Adolescent↗
PubMed1986

Specific causes of death in miners and ex-miners of the Rhondda Fach 1950-80.

The specific causes of death for miners and ex-miners of the Rhondda Fach have been examined in detail using the data base provided by the 30 year follow up. The main findings are the lower specific mortality for those with category A, compared with those with categories 0, 1, 2, and 3, for all circulatory diseases (particularly ischaemic heart disease) and the raised mortality for gastric cancer. These results are surprising because a high proportion of those with, especially, categories 2 and 3 developed category A during the 30 years but fail to show the specific death rates typical of those with category A. Possible reasons for this are discussed and an explanation put forward.

Cardiovascular Diseases↗
PubMed1986

Effects of 6-hydroxydopamine on the hypothalamo-pituitary-adrenocortical axis.

Female rats were treated with two intraventricular injections each of 350 micrograms 6-hydroxydopamine (6-OHDA) and used for experiment 4 or 14 days later. The response to laparotomy, as assessed by subsequent in vitro corticosterone release, was unaffected by the drug, but that to the smaller stress of a skin cut was significantly reduced. Both fast and delayed feedback responses to corticosterone administration were still evident in 6-OHDA-treated animals. When determined 14 days after treatment, hypothalamic concentrations of epinephrine (E) and norepinephrine (NE) were reduced by 46 and 84%, respectively. There was no significant change in content of immunoreactive corticotropin-releasing factor (CRF-41). The acetylcholine-stimulated release of CRF bioactivity from control hypothalami incubated in vitro was significantly inhibited by E or NE, with E being at least 10 times more potent on a molar basis. This effect of NE was enhanced in hypothalami removed from 6-OHDA-treated rats, complete inhibition of acetylcholine-stimulated release of CRF being produced by 0.6 nM NE, as opposed to 6.0 nM for untreated controls. At the level of the anterior pituitary gland, tissue content of adrenocorticotropin (ACTH) was unaffected by treatment, but that of luteinizing hormone (LH) in the same tissues was significantly increased. The corticotrophic response of fragments of the gland incubated or perifused in vitro to hypothalamic extract, CRF-41, arginine vasopressin or E was reduced. In contrast, the response of the tissue to gonadotropin-releasing hormone (GnRH) added in vitro was not significantly affected.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1986

The combination of 17 alpha-hydroxyprogesterone and 11-epicortisol prevents the delayed feedback effect of natural and synthetic glucocorticoids.

Subcutaneous injection of 400 micrograms/100 g body weight of corticosterone (B) 2 h previously in male rats prevented the stress response, as assessed by the ability of adrenal glands removed from these animals to produce endogenous B. Two injections of a combination of 17 alpha-hydroxyprogesterone and 11-epicortisol, the first given 30 min before and the second with the B, were able to block this inhibitory effect on the stress response. Neither of the steroids alone was effective in this regard. The combination was also effective against the early delayed feedback effects of 400 micrograms/100 g body weight cortisol, prednisolone or beclomethasone dipropionate in the same system. The minimum effective dose for reversal of feedback by B or beclomethasone dipropionate (2 mg/100 g body weight of each antagonist) was lower than that required for the same effect against prednisolone or cortisol (5 mg/100 g body weight). Previous injection of B also abolished the ability of anterior pituitary gland fragments to respond to corticotropin-releasing factors (CRFs) added in vitro, an effect which was not abolished by the injection of the combination of putative antagonistic steroids. From experiments designed to measure the ability of 17 alpha-hydroxyprogesterone and 11-epicortisol to compete with 3H-corticosterone in binding to macromolecular components in hypothalamic, hippocampal and pituitary cytosolic preparations, it was deduced that the competition seen in the hypothalamic and hippocampal, rather than the pituitary, preparations was in better accord with the effect seen on the stress response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

In vitro hemodynamic characteristics of tissue bioprostheses in the aortic position.

The in vitro hemodynamic characteristics of a variety of old and new generation porcine and bovine pericardial bioprostheses were investigated in the aortic position under pulsatile flow conditions. The following valves were studied: Carpentier-Edwards porcine (Models 2625 and 2650), Carpentier-Edwards pericardial, Hancock porcine (Models 242, 250, and 410), Hancock pericardial, and Ionescu-Shiley (standard and low-profile) bioprostheses. The pressure drop results indicated that the old design valves had performance indices in the range of 0.30 to 0.42, whereas the new low-pressure fixed designs have performance indices of 0.50 to 0.70. Flow visualization and velocity and turbulent shear stress measurements, conducted with a two-dimensional laser Doppler anemometer system, indicated that all tissue valve designs created jet-type flow fields. The intensity of the jets and turbulence levels were less severe with the new designs. The old designs created higher peak jet velocities and higher levels of turbulent shear stresses. On the whole, pericardial bioprostheses have better in vitro hemodynamic characteristics than porcine bioprostheses. These observations should have applications regarding the clinical choice of bioprosthetic valves and have implications regarding further improvements in the preparation and design of bioprosthetic valves.

Aortic Valve↗
PubMed1986

Panic disorder: epidemiology in primary care.

One hundred ninety-five patients in a primary care practice were screened with the National Institute of Mental Health Diagnostic Interview Schedule, a structured psychiatric interview, so that the epidemiology of panic disorder could be studied. Thirteen percent of the patients met criteria described in the Diagnostic and Statistical Manual of Mental Disorders, ed 3 (DSM-III) for panic disorder (6.7 percent if the DSM-III exclusionary criteria are used). An additional 8.7 percent of patients, labeled in the study as having simple panic, had four or more autonomic symptoms of panic disorder but did not meet DSM-III criteria (three panic attacks in a three-week period). Compared with controls, patients with panic disorder or simple panic had a significantly higher lifetime risk of major depression, multiple phobias, and avoidance behavior and higher scores on their psychological distress scales. Patients with panic disorder and simple panic often misinterpreted their symptoms as being due to a physical illness and had significantly higher scores on the somatization scale of the SCL-90 and on a medical review of symptoms than did the controls with no panic disorder. It is important to diagnose panic disorder accurately because double-blind placebo-controlled studies have demonstrated the efficacy of psychopharmacologic treatments, including tricyclic antidepressants (notably imipramine and desipramine), the high-potency benzodiazepine (alprazolam) and monoamine oxidase inhibitors (phenelzine). Primary care physicians, by screening patients with complaints of tension and anxiety, as well as multiple unexplained somatic complaints for panic disorder, may be able to reduce somatic preoccupation and disease phobia by instituting effective therapy.

Adolescent↗
PubMed1985

Measurement of neutral sugars in glycoproteins as dansyl derivatives by automated high-performance liquid chromatography.

Automated high-performance liquid chromatography was used to analyse dansylhydrazine derivatives of neutral sugars in unfractionated acid hydrolysates of four well-characterized glycoproteins: fetuin, ovalbumin, alpha-1-acid glycoprotein and bovine submaxillary mucin. After a simple single-step derivatization at 65 degrees C the sugar derivatives in protein hydrolysates chromatographed as single peaks on reversed-phase C18 columns. The isocratic solvent consisted of 20% (v/v) aqueous acetonitrile containing 0.01 M formic acid, 0.04 M acetic acid and 0.001 M triethylamine. The triethylamine significantly increases the sugar peak height at 254 nm. Repeated automatic sample injection without deterioration of column performance or interference from dansyl hydrazine is not possible with published methods, but was achieved by cleaning the column between each analysis with a solvent of 20% (v/v) acetonitrile and 80% (v/v) methanol. Hydrolysis with 2 M trifluoroacetic acid is superior to 2 M hydrochloric acid for both sugar recovery and convenience but must continue for 6-8 h at 105 degrees C to ensure complete sugar release. We confirmed that mannose is present in most preparations of human high-molecular-weight salivary glycoproteins, and also examined purified bovine skin proteodermatan sulphate. p-Nitrophenylhydrazine derivatives of neutral sugars are readily produced, but do not chromatograph as successfully as the dansyl derivatives while phenylhydrazine derivatives are not easily produced at 65 degrees C. Further development of the method should be possible by producing other hydrazine derivatives of neutral sugars.

Autoanalysis↗
PubMed1985

Circles of wisdom.

Explore the source record for details and available documents.

Hospital Departments↗
PubMed1985

Spread and distribution of human T-cell leukaemia virus type I-reactive antibody among baboons and monkeys in the northern and eastern Transvaal.

Antibodies which probably indicate infection with human T-cell leukaemia virus type I (HTLV-I) were determined in three species of non-human primates from several localities. A significant prevalence among chacma baboons and vervet monkeys was confirmed. According to sero-epidemiological evidence that HTLV-I infection is predominantly sexually transmitted between adult animals; comparison of prevalence rates between localities or species should therefore take sexual maturity into account. It appears unlikely that transmission from non-human primates to humans is frequent.

Animals↗
PubMed1985

Distribution and possible spread of human T-cell leukaemia virus type I in human communities in the northern and eastern Transvaal.

The prevalence of serum antibodies which probably indicate infection with a human T-cell leukaemia virus type I was determined among random population samples of more than 100 healthy black individuals in several localities in Transvaal. The percentage of seropositive subjects increases northwards and eastwards, where geoclimatic conditions are similar to those of endemic areas elsewhere in the world. The comparatively higher prevalence among females in the Kruger National Park suggests that this is predominantly a sexually transmitted disease.

Adult↗
PubMed1985

High-dose cisplatin in patients with advanced malignancies.

A study was conducted to determine if cisplatin (CDDP) can be given at higher doses than usual, utilizing aggressive supportive measures. Twelve patients were entered into three dose levels of CDDP: level I, 180 mg/m2 given as a short infusion; level II, 220 mg/m2 also given as a short infusion; level III, 200 mg/m2 divided in five daily doses, each infused over 6 hours. In all cases, CDDP was dissolved and given in 250 ml of a 5% saline solution. For levels I and II, intravenous hydration with 200 to 250 ml/hour D5 1/2NS with potassium and magnesium supplements, was started 24 hours before therapy and continued for 3 to 4 days after, longer if nausea persisted. Mannitol was given before (25% solution, 50 ml bolus) and after (20% solution, 500 ml over 3 hours) CDDP. At level III hydration with the same intravenous (IV) fluids was begun the day before therapy and continued without interruption at 200 to 250 ml/hour for a minimum of 24 hours after the completion of the 5 days of chemotherapy. Each daily dose of CDDP was preceded by injection of mannitol (25% solution, 50 ml bolus) and accompanied by a 6-hour infusion of 1000 ml 20% mannitol. Three patients received five CDDP courses at level I; 4 patients, seven courses at level II; and 5 patients, seven courses at level III. Ototoxicity was dose-limiting in three patients at level II. Transient elevation of serum creatinine was seen following two courses at level I and two courses at level II. The renal impairment was asymptomatic in all cases; dialysis was not needed. At level II, leukocyte nadir counts between 1.0 and 2.0 X 10(3)/mm3 were seen following two courses and between 2.0 and 3.0 X 10(3)/mm3 following three courses. Platelet nadir counts below 50 X 10(3)/mm3 were recorded after four courses and between 50 and 100 X 10(3)/mm3 after one course. Nausea and vomiting occurred frequently, but were tolerable. At level III, myelosuppression was dose-limiting. Nadir leukocyte counts between 1.0 and 2.0 X 10(3)/mm3 followed four courses and between 2.0 and 3.0 followed one course. Nadir platelet counts below 50 X 10(3)/mm3 were seen after three courses; two patients required prophylactic platelet transfusions. Nadirs between 50 and 100 X 10(3) platelets/mm3 followed three further courses. Ototoxicity and nephrotoxicity did not occur at level III.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1985

The reduction of inter- and intra-observer variability for defining regions of interest in nuclear medicine.

The use of region-of-interest (ROI) techniques to quantify data obtained in radionuclide images is commonplace. However, the reproducibility of quantitation due to inter- and intra-observer variations using particular methods of deriving ROIs is often not appreciated. We examined such variations in the results obtained by four independent observers of varying experience using four methods of depicting a ROI about an organ. The set of image data consisted of renal scans with varying target-to-background ratios, and the ROI facilities included two edge-detection methods. The results indicated that, once observers were experienced with edge-detection methods, a lower inter- and intra-observer variation could be achieved, although the technique of 'shrinking' a ROI about a subjectively chosen display level was reasonably satisfactory. In terms or reproducibility, the least satisfactory method of depicting a ROI was the commonly used manually guided 'bug' around arbitrarily chosen display levels representing the boundary of an organ.

Humans↗