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Biomedical subjects

M Jones

Publications and source records attributed to M Jones.

At least 685 records · Page 38Linked to original sources
PubMed1988

Type A behaviour and coronary atherosclerosis.

The relation of the Type A behaviour pattern to coronary atherosclerosis was assessed in a sample of 519 coronary angiography patients. Type A measures were the Structured Interview and the Framingham questionnaire. Angiographic indices included a composite coronary occlusion index and number of coronary vessels significantly diseased. Univariate analysis involving the entire sample showed no significant relation between Type A and severity of coronary vessel disease. Analyses for two subsamples, namely males currently employed in white collar occupations and persons found to have significant disease at angiography, also failed to indicate a relationship between Type A and coronary disease. Multivariate analysis revealed sex, cholesterol and age to be risk factors for atherosclerosis; Type A behaviour was not. The implications of these findings are discussed.

Adult↗
PubMed1988

The definition of the 'no change' category in patients treated with endocrine therapy and chemotherapy for advanced carcinoma of the breast.

In the criteria used for assessment of response to treatment for advanced breast cancer the definition of no change (NC) is clear; however, there is no indication of the duration of stabilization required for patients to qualify for this category of response. We have made the assumption that NC is a worthwhile category of response if the overall time to progression (TTP) and survival of this group is not significantly different from patients with partial remissions (PR). Two hundred and sixty-three evaluable patients treated with endocrine therapy and 302 evaluable chemotherapy-treated patients were studied and the TTP and survival curves for PR and periods of NC from 1 to 6 months compared. For the endocrine-treated patients the TTP and survival curves for NC became non-significantly different from the PR curves after 4 and 5 months respectively. For chemotherapy-treated patients the TTP curves became non-significantly different from PR at 4 months and for survival the period was 3 months. In order to define NC as a useful category of response and to eliminate the possibility that NC taken for a shorter period could simply represent a slowly progressive tumour, we suggest that the minimum period of disease stabilization be taken as 5 months for both endocrine- and chemotherapy-treated patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1988

Prognostic factors in stage I and II high and intermediate grade non-Hodgkin's lymphoma.

Between 1975 and 1986, the Manchester Lymphoma Group treated 127 patients with localized (Stages I/II) high and intermediate grade non-Hodgkin's lymphoma (NHL) on one of three protocols of combined involved field radiotherapy and chemotherapy. The study included patients with widespread bulky abdominal disease providing there was no apparent spread outside the abdomen and the liver was not involved with metastatic disease. The median duration of follow-up was 70 months. The complete response rate was 86% and the overall 5-year survival was 70%. The 5-year relapse-free survival of the complete responders was 80%. Cox model multivariate analysis showed that bulk disease (greater than 5 cm), low serum albumin and gut involvement were the pretreatment factors associated with shorter survival. When remission status was included in the model the attainment of a complete response was the major determinant of long-term survival but bulk disease and gut involvement were still significant adverse predictors for survival. These factors need to be assessed when analysing results of therapy in NHL and in the design of future treatment strategies.

Adult↗
PubMed1988

The effective use of intrapleural bupivacaine for analgesia after thoracic and subcostal incisions in children.

Twenty-four patients having undergone thoracotomies and subcostal incisions were treated for 24 hours with intrapleural bupivacaine with epinephrine. Vital signs, pain scores, and serum bupivacaine levels were recorded. No patient required narcotic medications and all patients obtained adequate analgesia. There were no complications of the technique or toxicity of the drug. Further studies need to be performed to extend the duration of use, to determine pharmacokinetics, and to compare with other techniques.

Abdomen↗
PubMed1988

Development of a new physicochemical model for brain penetration and its application to the design of centrally acting H2 receptor histamine antagonists.

A rational approach to the design of centrally acting agents is presented, based initially upon a comparison of the physicochemical properties of three typical histamine H2 receptor antagonists which do not readily cross the blood-brain barrier with those of the three brain-penetrating drugs clonidine (6), mepyramine (7) and imipramine (8). A good correlation was found between the logarithms of the equilibrium brain/blood concentration ratios in the rat and the partition parameter, delta log P, defined as log P (1-octanol/water)-log P (cyclohexane/water), which suggests that brain penetration might be improved by reducing overall hydrogen-bonding ability. This model has been employed as a guide in the design of novel brain-penetrating H2 antagonists by the systematic structural modification of representatives of different structural types of H2 antagonists. Although marked increases in brain penetration amongst congeners of cimetidine (1), ranitidine (9), and tiotidine (10) were achieved, no compound was found with an acceptable combination of H2 antagonist activity (-log KB in the guinea pig atrium greater than 7.0) and brain penetration (steady-state brain/blood concentration ratio greater than 1.0). Conversely, structural modification of N-[[(piperidinyl-methyl)phenoxy]propy]acetamide (30) led to several potent, novel compounds which readily cross the blood-brain barrier. One of these, zolantidine (SK&F 95282, 41), whose -log KB is 7.46 and steady-state brain/blood ratio is 1.4, has been identified for use in studying histaminergic H2 receptor mechanisms in brain. Comparison of delta log P values with the logarithms of the brain/blood ratios for 20 structurally diverse compounds for which data became available confirms a highly significant correlation and supports the general validity of this model.

Algorithms↗
PubMed1988

The relationship of body weight to response to endocrine therapy, steroid hormone receptors and survival of patients with advanced cancer of the breast.

High body weight is associated with increased production of oestrogens which may influence the clinical behaviour of breast cancer. We have examined the influence of body weight on the response to endocrine therapy, steroid hormone receptor content and survival in 227 women who either presented with or developed advanced cancer of the breast. One hundred and thirty-three (59%) patients presented with operable disease and 94 (41%) with locally advanced tumours. Two hundred (88%) were treated by tamoxifen and 27 (12%) by ovarian ablation. High body weight was correlated with advanced tumour stage (P = 0.002) and progesterone receptor (PR) positivity (P = 0.01), but not with the presence of oestrogen receptor (ER P = 0.21). The association between high body weight and PR positivity was particularly noticeable among ER positive tumours. There was no significant relationship between the nature of the response to therapy and weight (P = 0.57). There was no significant difference in survival from the start of endocrine therapy (P = 0.95), nor the time to progression of disease (P = 0.29) between patients above and below the median weight of 64 kg. Among the patients with operable disease, there was no difference in overall survival (P = 0.42), relapse free survival (P = 0.69), and survival from the start of endocrine therapy (P = 0.85) according to body weight.

Body Weight↗
PubMed1988

In vitro interactions of amikacin and beta-lactam antibiotics against amikacin-resistant gram-negative bacilli.

We tested 42 strains of amikacin-resistant gram-negative bacilli with amikacin in combination with six beta-lactam antibiotics using the checkerboard and time-kill curve techniques. Synergism was demonstrated with time-killing curve in 43-68% of the strains tested. Ceftazidime plus amikacin was the most active combination by the checkerboard technique, while amikacin-cefoperazone was the most active combination by the time-killing curve technique against Pseudomonas aeruginosa. Discrepancies were found between the results of the two methods used.

Amikacin↗
PubMed1988

Advances in prosthetic heart valves: fluid mechanics of aortic valve designs.

The in vitro hemodynamic characteristics of a variety of mechanical and tissue heart valve designs used during the past two decades were investigated in the aortic position under pulsatile flow conditions. The following valve designs were studied: Starr-Edwards ball and cage (model 1260), Björk-Shiley tilting disc (convexo-concave model), Medtronic-Hall tilting disc, St. Jude Medical bileaflet, Carpentier-Edwards porcine and pericardial (models 2625, 2650 and 2900), Hancock porcine (models 250 and 410) and Ionescu-Shiley standard pericardial. The Starr-Edward ball and cage, Björk-Shiley tilting disc, Carpentier-Edwards porcine (model 2625) and Ionescu-Shiley standard pericardial valves were designed prior to 1975, while the Medtronic-Hall tilting disc, St. Jude Medical bileaflet, Hancock porcine (model 250), Hancock II porcine (model 410), Carpentier-Edwards porcine (model 2650) and Carpentier-Edwards pericardial (model 2900) valves were designed after 1975. The pressure drop results indicated that the valves designed prior to 1975 had performance indices of 0.30 to 0.45, whereas the valves designed after 1975 had performance indices of 0.40 to 0.70. The regurgitant volumes were higher for the mechanical designs (5.0 to 11.0 cm3/beat) compared to the tissue bioprostheses (1.0 to 5.0 cm3/beat). Two-dimensional laser Doppler anemometry studies indicated that the valves designed after 1975 tended to create more centralized flow fields, with reduced levels of turbulent shear stresses. However, none of the current valve designs is ideal: they all create areas of stasis and/or regions of low velocity reverse flow; and regions of elevated turbulent shear stresses that are capable of causing sub-lethal and/or lethal damage to the formed elements of blood.

Aortic Valve↗
PubMed1988

Suppression of emotions in essential dyspepsia and chronic duodenal ulcer. A case-control study.

It remains controversial whether psychologic factors contribute to the onset or chronicity of non-ulcer dyspepsia (NUD) and duodenal ulcer. Although such patients on conventional psychologic testing have no clearly defined specific personality type, an inability to express emotion, which may result in excessive autonomic arousal, has been suggested to be important on theoretic grounds. The aim of this study was to assess whether the latter defect is associated with the subgroup of NUD patients with essential dyspepsia and with patients with chronic duodenal ulcer. Eighty-one patients with essential dyspepsia and 53 patients with duodenal ulcer studied after endoscopy were compared with 82 randomly selected dyspepsia-free community controls. All were assessed with the Courtauld emotional control scale, a valid and objective self-report measure. Control of anger, anxiety, unhappiness, and total emotional control over negative reactions were similar in all three groups. It is concluded that patients with essential dyspepsia and duodenal ulcer who present for investigation are unlikely to repress emotional reactions consciously.

Adult↗
PubMed1988

Psychosocial and childhood factors in essential dyspepsia. A case-control study.

A subgroup of patients with endoscopically diagnosed non-ulcer dyspepsia have no definite cause for their symptoms, termed essential dyspepsia; such patients have been considered to have 'nervous dyspepsia'. To determine whether social and environmental factors are of importance, both in childhood (before the onset of symptoms) and in adult life, 109 patients with essential dyspepsia and 109 randomly selected dyspepsia-free community controls (matched for age, sex, and one measure of social grade-suburb of residence) were studied. Socioeconomic status, marital status, childhood environment, family structure, and migration were measured. An increased risk of essential dyspepsia was associated with one aspect of social status incongruity; compared with controls, patients had a lower occupational status than their place of residence indicated (OR = 2.3; 95% CI, 1.5-3.5). There was a trend for patients to report an unhappy childhood (OR = 2.4; 95% CI, 0.9-6.7). Being unmarried, undergoing parental separation during childhood, the patient's age at parental separation, the number of siblings, birth order, country of birth, and years of residence were not significantly associated with essential dyspepsia. The importance of psychosocial and childhood factors in essential dyspepsia is probably small.

Adult↗
PubMed1988

The effects of antithymocyte globulin on natural killer cells.

We studied the effects of antithymocyte globulin (ATG) on natural killer (NK) cell activity to evaluate whether ATG may be useful in preventing NK-mediated disorders such as rejection of mismatched bone marrow (BM). We found that four of four lots of ATG eliminated greater than 95% of NK activity against K562. The effect of ATG on NK-mediated suppression of granulocyte-macrophage colony-forming units (CFU-GM) was also studied. ATG at a concentration of 1.0 mg/ml completely abrogated NK-mediated suppression of CFU-GM, as did monoclonal antibody Leu 11b/anti-CD 16 and complement (BRC). In contrast, OKT3/anti-CD3 had no effect on NK-mediated suppression of CFU-GM, suggesting that the effector cells were most likely NK cells rather than T cells. We also studied the effect of gamma interferon (INF) on NK-mediated suppression of CFU-GM and showed that eliminating NK cells with Leu 11b and BRC or ATG did not reduce gamma INF suppression of CFU-GM, suggesting that gamma INF directly suppressed CFU-GM rather than augmenting NK activity. Based on these results we postulate that ATG may have a role in the prevention or treatment of suppression of hematopoiesis thought to be caused by NK cells.

Colony-Forming Units Assay↗
PubMed1988

Role of volume expansion in severe pre-eclampsia.

Fifteen primigravid patients with severe pregnancy-induced hypertension were studied by catheterization of the right side of the heart. A hemodynamic protocol was implemented that required maintaining colloid osmotic pressure above 17 millimeters of mercury, pulmonary capillary wedge pressure below 15 millimeters of mercury and the mean arterial pressure in a very narrow range throughout labor and delivery and for 48 hours postpartum. The initial colloid osmotic pressures and pulmonary capillary wedge pressures were 18.0 +/- 2.6 and 10.5 +/- 4.0 millimeters of mercury, respectively, and remained essentially unchanged throughout the post partum period. The only benefit derived from volume expansion in these patients appeared to be the absence of acute fetal distress after the initiation of antihypertensive therapy. Six of 15 patients had late fetal stress develop during labor, suggesting that aggressive volume repletion and colloid osmotic pressure correction in pregnancy-induced hypertension does not effect the over-all incidence of fetal distress. We recommend that correction of colloid osmotic pressure be restricted to instances in which extremely low values (less than 12 millimeters of mercury) or a prolonged negative colloid osmotic pressure to pulmonary capillary wedge pressure gradient are identified. Finally, the benefit of volume expansion in pregnancy-induced hypertension appears to be the prevention of sudden and profound drops in blood pressure with antihypertensive therapy--not the prevention of fetal distress during labor.

Antihypertensive Agents↗
PubMed1988

Ventricular aneurysms and other lesions produced by the struts of bioprosthetic valves implanted in sheep.

Damage to the posterolateral wall of the left ventricle was found in eight of approximately 700 sheep undergoing mitral valvular replacement as part of animal model studies of bioprosthetic valves. The damage consisted of left ventricular aneurysms in five animals, subacute rupture of the left ventricle in one, acute left ventricular laceration in one, and endocardial scarring in one. Six of the eight bioprostheses were bovine pericardial valves, including five low-profile valves and one standard valve; of the two porcine bioprostheses, one was intentionally oversized and the other was a low-profile supra-annular valve. In each of these animals the damage appeared to have been caused by contact between the most posterior strut of the bioprosthesis and the left ventricular wall.

Animals↗
PubMed1988

In vitro velocity and turbulence measurements in the vicinity of three new mechanical aortic heart valve prostheses: Björk-Shiley Monostrut, Omni-Carbon, and Duromedics.

The in vitro velocity and turbulent shear stress fields created by three new mechanical valve designs (size 27 mm) were studied in the aortic position under pulsatile flow conditions. The following valves were studied: Björk-Shiley Monostrut tilting disc, Omni-Carbon tilting disc, and Duromedics bileaflet. All three valve designs created low pressure gradients with effective orifice areas in the range of 3.10 to 3.90 cm2. Both tilting disc designs created major and minor orifice jets, which were asymmetric in size. The peak velocities of the major and minor orifice jets were, however, of the same magnitude (200 cm/sec). The Omni-Carbon valve created a more even flow distribution through the minor orifice compared with the Björk-Shiley design. Regions of stagnation/flow separation were observed immediately adjacent (ie, distal) to the minor orifice strut and the pivot guards of the Björk-Shiley and Omni-Carbon valve designs, respectively. The Duromedics valve created relatively centralized flow. However, a major portion of the flow occurred through the two lateral orifices. Regions of flow separation/stagnation were observed adjacent to the valve sewing ring in the area of the valve pivot (hinge) mechanism. All three valve designs did create elevated turbulent shear stresses, with peak values in the range of 1000 to 2000 dynes/cm2 and mean values in the range of 100 to 1000 dynes/cm2. Such elevated shear stresses could cause sublethal and/or lethal damage to cellular blood elements. In an overall analysis, these new-generation low-profile mechanical valves are hemodynamically comparable to the Medtronic Hall and St. Jude Medical mechanical valves and are superior to the older-generation mechanical valves. However, it is unlikely that these valve designs will eliminate the problems of thrombosis, thromboembolic complications, and hemolysis.

Aortic Valve↗
PubMed1988

Design of clinical database management systems and associated software to facilitate medical statistical research.

Clinical databases are growing rapidly. The clinical database is heavily used for medical research in many settings. This paper discusses design features for medical databases that facilitate their use for research. The database management system should allow complex data structures, have a syntax-facilitating collection of longitudinal data, interface with major statistical software packages, allow an extensive data dictionary, conveniently merge files, facilitate archival documentation, have an associated data entry system that allows complex logical checking, and have coordinated mainframe and microcomputer software.

Biometry↗