Biomedical subjects

C J Jones

Publications and source records attributed to C J Jones.

At least 181 records · Page 10Linked to original sources

PubMed1991

An echocardiographic assessment of atrial mechanical behaviour.

Relations between movement of the atrioventricular ring and changes in left atrial and ventricular dimensions were studied by echocardiography and compared with apexcardiography and Doppler mitral flow velocity traces in 20 healthy controls and in patients with left ventricular hypertrophy (n = 28) or dilatation (n = 16). During left ventricular systole the atrioventricular ring, a structure common to ventricle and atrium, moved towards the ventricular apex, thus increasing left atrial volume. This action matched pulmonary venous return because it was in phase with the transverse left atrial dimension measured from aortic root to posterior left atrial wall. During early diastole, the mitral ring moved rapidly towards the atrium as transmitral flow accelerated. This requires a force directed from ventricle to atrium, likely to be the result of elastic recoil arising from compression of the ventricular myocardium or stretching of the atrial myocardium during ventricular systole. Two additional mechanisms of ventricular filling with atrial systole were recognised: (a) an increase in ventricular volume as the atrioventricular ring moved upwards and (b) transverse left ventricular expansion by pressure driven transmitral flow. The former is undetectable by Doppler from the apex; it accounted for 10% of ventricular filling in the healthy controls, but for significantly less in those with ventricular dilatation. In left ventricular hypertrophy, left ventricular filling was maintained by both mechanisms compensating for the reduced increase in volume early in diastole. Interactions between the atrium and ventricle are functionally important during ventricular systole, early diastole, and in atrial systole. They are not included in the traditional separation of atrial function into reservoir, conduit, and pump functions.

Atrial Function, Left↗

PubMed1991

Insulin and glucose do not affect the glycogen content in isolated and cultured trophoblast cells of human term placenta.

The influence of insulin and glucose on the glycogen content of isolated trophoblast cells was measured for the first time. The cells were obtained by tryptic digestion of villous tissue from term placentae of 15 healthy women, further purified on a Percoll gradient and enriched by employing a monoclonal anti HLA class-I antibody. The cells stained intensively with PKK1 and exhibited the structural and phenotypical characteristics of intermediate and syncytiotrophoblasts. The mean glycogen content of cells cultured in Dulbecco's Modified Eagle's Medium with 5.5 mM glucose was 17.7 +/- 3.2 micrograms/mg protein, remained constant from days 1-4, and was unaltered by higher glucose concentrations (17 and 28 mM) in the medium. Between 2-5 h after a medium change, the cells contained 50% more glycogen than at the time of replacement. Short term (0-5 h) as well as long term incubations (24 h) with both pathological (10(-8) M) and physiological (10(-9) M) concentrations of insulin had no effect, with respect to either the rate of increase in glycogen or the maximum level. We conclude that the glycogen content of isolated syncytiotrophoblasts in vitro is invariant to extracellular glucose concentrations and is not regulated by insulin. This suggests that cells other than syncytiotrophoblasts and their immediate precursors account for the reported alterations of glycogen content in normal human term placenta in vitro under hyperglycemic or hyperinsulinemic conditions.

Cells, Cultured↗

PubMed1991

Elevated nicotine levels in cervical lavages from passive smokers.

One hundred forty-five nonsmokers found to have normal cytologic diagnoses on routine Pap smears were interviewed regarding environmental exposure to tobacco smoke, and a 3 ml saline lavage of the cervix was collected for measurement of cervical nicotine levels by gas chromatography-mass spectroscopy. Nicotine levels tended to be highest among women exposed to tobacco smoke in the home, intermediate in women exposed only outside the home, and lowest in women recalling no exposure (p = 0.001).

Adolescent↗

PubMed1991

Spatial and temporal dispersion of immature Ixodes dammini on Peromyscus leucopus in northwestern Illinois.

Infestation by immature Ixodes dammini and infection by Borrelia burgdorferi of the white-footed mouse Peromyscus leucopus were studied in Castle Rock State Park in northwestern Illinois during June-October 1990. Prevalence and intensity of infestation of larvae on mice were highest in August with a smaller peak in early June. The distribution of larvae on mice was highly aggregated during each of the sampling periods. Aggregation appears to be the result of a series of nonrandom successful attachments by single larvae, rather than of simultaneous attachment by clumps of larvae. Infection rate of mice by B. burgdorferi averaged 21.4% with a peak of 28.6% in August. A comparison of the numbers of attached immature ticks collected from mice and of questing ticks collected through dragging indicated that the larvae-to-nymph ratio was higher on mice than on drags. Given the low total numbers of nymphs collected from mice, this suggests a potential role for other hosts of I. dammini nymphs in northwestern Illinois.

Animals↗

PubMed1990

Risk factors for in situ cervical cancer: results from a case-control study.

A case-control study of 293 patients with in situ cervical cancer and 801 community controls was conducted between 1982 and 1984 in five geographic areas in the United States. Relative risk (RR) was elevated among women reporting multiple sexual partners (RR for greater than or equal to 5 partners = 5.0), a history of an abnormal Papanicolaou smear (RR = 5.0), interval since last Papanicolaou smear (RR for greater than or equal to 10-year interval versus 0- to 2-year interval = 4.1), use of oral contraceptives (RR for greater than or equal to 10 years use = 1.4), a history of nonspecific genital infection (RR = 2.6), and smoking (RR for current smokers = 1.9). Risk was low among diaphragm users (RR for greater than 2 years use = 0.5). Neither age at first coitus nor number of births was predictive of risk of in situ disease. Comparisons between this analysis and risk factors previously identified for invasive cervical cancer in this same study indicate that the risk factors were quite similar.

Adult↗

PubMed1990

Stoichiometric analysis of the flagellar hook-(basal-body) complex of Salmonella typhimurium.

The stoichiometries of components within the flagellar hook-(basal-body) complex of Salmonella typhimurium have been determined. The hook protein (FlgE), the most abundant protein in the complex, is present at approximately 130 subunits. Hook-associated protein 1 (FlgK) is present at approximately 12 subunits. The distal rod protein (FlgG) is present at approximately 26 subunits, while the proximal rod proteins (FlgB, FlgC and FlgF) are present at only approximately six subunits each. The stoichiometries of the proximal rod proteins and hook-associated protein 1 are, within experimental error, consistent with values of 5 or 6, and 11, respectively. Such values would correspond to either one or two turns of a helical structure with a basic helix of approximately 5.5 subunits per turn, which is the geometry of both the hook and the filament and, one supposes, the rod and hook-associated proteins. These stoichiometries may derive from rules for the heterologous interactions that occur when a helical structure consists of successive segments constructed from different proteins; the stoichiometries within the hook and the distal portion of the rod must, however, be set by different mechanisms. The stoichiometries for the ring proteins are approximately 26 subunits each for the M-ring protein (FliF), the P-ring protein (FlgI), and the L-ring protein (FlgH); the protein responsible for the S-ring feature is not known. The rings presumably have rotational rather than helical symmetry, in which case the stoichiometries would be directly constrained by the intersubunit bonding angle. The ring stoichiometries are discussed in light of other information concerning flagellar structure and function.

Amino Acid Sequence↗

PubMed1990

Lectin histochemistry of the mast cell: heterogeneity of rodent and human mast cell populations.

Mast cell granules contain a variety of N-linked saccharides. Heterogeneity of the expression of these saccharides in mast cells was studied in rodent and human tissues which were so selected as to contain all the mast cell subsets previously identified using other criteria. Dermal and intestinal mucosal mast cells were stained with lectins using an avidin-biotin system. It was found that dermal and subepidermal mast cells in the rat and mouse, and mucosal and dermal human mast cells showed very similar lectin binding properties to each other, with a fine variation in the intensity of staining with certain lectins. Rat mucosal mast cells, however, showed a distinctive pattern of lectin binding which was not seen in mast cells from any other tissue studied. The chemical basis of the differences seen were deduced and the possible significance of these structural variations is discussed.

Alcian Blue↗

PubMed1990

Effects of the inotrope DPI 201-106 on cardiac performance following cardiac surgery.

The haemodynamic, cardiac metabolic and electrocardiographic effects of the intravenous inotropic agent DPI 201-106, in 20 and 40 milligram doses, were studied in patients after coronary arterial bypass grafting. The patients were randomly allocated to receive placebo or DPI 201-106. Those receiving the active drug received either the 20 or the 40 milligram dosages of DPI 201-106. Both the placebo and the active drug were infused over 20 minute periods. Two baseline readings confirmed haemodynamic stability, and readings were taken immediately following the infusions and then at 20 minutes and at 40 minutes afterwards. Comparison of all the haemodynamic and metabolic data did not reveal any significant intra or inter group differences. Comparison of the electrocardiographic data revealed some differences. Patients receiving DPI 201-106 showed prolongation of the QTc interval immediately following the infusions. Changes in ST segments and T waves were observed. Independent analysis of the affected electrocardiographs reported that the changes were suggestive of, but not pathognomonic of, myocardial ischaemia. The metabolic data showed that the electrocardiographic changes were not associated with any evidence of anaerobic metabolism. The indication for DPI 201-106 as a positive inotropic agent in patients following coronary revascularization surgery was not established.

Adult↗

PubMed1990

Abnormal arterial flow pattern in untreated essential hypertension: possible link with the development of atherosclerosis.

1. We compared the velocity waveforms in the superficial femoral artery measured by multichannel Doppler ultrasound in 45 subjects: 21 patients with untreated essential hypertension and 24 normal subjects of similar age and sex. 2. The pattern of arterial flow was abnormal in hypertensive patients, with the acceleration time, the duration of reverse flow and the time to maximum flow reversal being abbreviated. The internal arterial diameter, calculated from the velocity profile, was reduced despite raised pressure, suggesting altered arterial wall mechanics in essential hypertension. 3. These abnormalities will influence the wall shear stress, a major determinant of arterial function. The abnormal arterial wall mechanics and abnormal blood flow pattern may contribute to the increased risk of arterial disease in patients with untreated hypertension.

Adult↗

PubMed1990

Multivariate, replicated, single-subject, repeated measures designs and P-technique factor analysis: a review of intraindividual change studies.

The precise, quantitative portrayal of intraindividual change is a key goal of developmental researchers. Research designs particularly appropriate to selected aspects of this goal are multivariate, replicated, single-subject, repeated measures (MRSRM) designs. Data collected with these designs may be factor analyzed with P-technique factor analysis to elucidate, for each individual studied, patterns of systematic change. The nature of the factor patterns obtained for each individual can then be compared across individuals to determine the relative idiosyncrasy or generality of patterns of change. This paper extends an earlier review (Luborsky & Mintz, 1972) of studies using multivariate, single-subject, repeated measures designs and P-technique factor analysis. The emphasis here is on both more recent studies and the value of subject replication in creating a confluence of idiographic and nomothetic approaches to the study of behavior and behavioral development across the lifespan.

Factor Analysis, Statistical↗

PubMed1990

Forward and backward running waves in the arteries: analysis using the method of characteristics.

The one-dimensional equations of flow in the elastic arteries are hyperbolic and admit nonlinear, wavelike solutions for the mean velocity, U, and the pressure, P. Neglecting dissipation, the solutions can be written in terms of wavelets defined as differences of the Riemann invariants across characteristics. This analysis shows that the product, dUdP, is positive definite for forward running wavelets and negative definite for backward running wavelets allowing the determination of the net magnitude and direction of propagating wavelets from pressure and velocity measured at a point in the artery. With the linearizing assumption that intersecting wavelets are additive, the forward and backward running wavelets can be separately calculated. This analysis, applied to measurements made in the ascending aorta of man, shows that forward running wavelets dominate during both the acceleration and deceleration phases of blood flow in the aorta. The forward and backward running waves calculated using the linearized analysis are similar to the results of an impedance analysis of the data. Unlike the impedance analysis, however, this is a time domain analysis which can be applied to nonperiodic or transient flow.

Aorta↗

PubMed1990

Flagellar assembly in Salmonella typhimurium: analysis with temperature-sensitive mutants.

The process of flagellar assembly in Salmonella typhimurium was investigated by using temperature-sensitive mutants. The mutants were grown at the restrictive temperature and then at the permissive temperature, with radiolabel supplied in the first phase of the experiment and not the second, or vice versa. Flagellar hook-basal body complexes were then purified and analyzed by gel electrophoresis and autoradiography. The extent to which a given protein was labeled in the two phases of the experiment provided information as to whether it preceded or followed the block caused by the mutant protein. We conclude the following concerning flagellar assembly. The M-ring protein (FliF) is stably incorporated in the earliest stage detected, along with two previously unknown proteins, with apparent molecular masses of 23 and 26 kilodaltons, respectively, and possibly one of the switch components, FliG. Independent of that event and all other events, the P-ring and L-ring proteins (FlgI and FlgH) are synthesized and exported to the periplasm and outer membrane by the primary cellular export pathway. Rod assembly occurs by export (via the flagellum-specific pathway) of subunits of four proteins, FlgB, FlgC, FlgF, and FlgG, and their incorporation, probably in that order, into the rod structure; this stage requires the flhA and fliI genes, perhaps because they encode part of the export apparatus. Once rod assembly is complete, the FlgI and FlgH proteins assemble around the rod to form the P and L rings. The rod structure, which is only metastable while it is being constructed, becomes stable upon P-ring addition. Export (via the flagellum-specific pathway) and assembly of hook protein, hook-associated proteins, and filament protein then occur successively. A number of flagellar proteins, whose genetic origin and structural role are not yet known, were identified on the basis of their dependence on the flagellar master operon for expression.

Bacterial Proteins↗

PubMed1990

Functional importance of the long axis dynamics of the human left ventricle.

The role of longitudinally and circumferentially oriented fibres in left ventricular wall motion was examined by digitising echocardiograms of the mitral ring (whose motion reflects long axis change) and of the standard minor axis in 36 healthy individuals, 36 patients with coronary artery disease, 16 with left ventricular hypertrophy, 44 with mitral valve disease (24 of whom had undergone mitral valve replacement). In the controls long axis shortening significantly preceded minor axis shortening (mean (1 SD) difference 25 (40) ms) so that the minor axis increased more during isovolumic contraction (0.25 v 0.09 cm), indicating that the left ventricle became more spherical. Changes in the long and short axes were synchronous at end ejection and in early diastole in the controls. Epicardial excursion preceded endocardial excursion by 50 (20) ms at its peak. These time relations were consistently disturbed in all patient groups, irrespective of the extent of fractional shortening of the minor axis. The onset of long axis shortening was delayed, and this was often associated with premature shortening of the minor axis, the normal spherical shape change during isovolumic contraction was lost, and peak epicardial and endocardial changes became more synchronous. In patients with coronary disease these changes are the expected consequence of ischaemic injury to longitudinally orientated subendocardial fibres. In left ventricular hypertrophy their presence consistently showed systolic dysfunction when orthodox measures were still normal. They were more pronounced after mitral valve replacement when the papillary muscles had been sectioned; long axis shortening was reduced during systole and prolonged into early diastole, while normal shortening of the minor axis was maintained only by abnormal epicardial excursion. Relations between long and short axis motion in healthy individuals are characteristic, and their loss is an early index of systolic ventricular disease. These disturbances precede changes in orthodox measures such as fractional shortening or peak velocity of circumferential fibre shortening.

Cardiomegaly↗

PubMed1990

No effect of doxapram during enflurane-nitrous oxide anesthesia.

Doxapram was administered to 50 spontaneously breathing patients receiving enflurane and nitrous oxide for surgical anesthesia. A similar group acted as control. Significant depression of ventilation did not occur in the control group of patients, nor did doxapram produce a reduction of end tidal CO2 concentrations. It is suggested that surgical stimulation and concomitant nitrous oxide administration reduced the ventilatory depressant effect of enflurane and that the effect of doxapram was attenuated by the actions of enflurane on the peripheral chemoreceptors.

Adult↗

PubMed1989

The effects of intravenous nitroglycerin and isosorbide dinitrate on hemodynamics and myocardial metabolism.

Myocardial ischemia before and during coronary artery surgery is significant, because patients who develop perioperative myocardial ischemia have an increased incidence of postoperative myocardial infarctions. Thus, the prevention of ischemic episodes is of great importance. This study was undertaken to (1) compare the effects of intravenous nitroglycerin (NTG) with isosorbide dinitrate (ISDN); (2) investigate if the continuous infusion of nitrates had beneficial effects on cardiac performance and metabolism; and (3) compare the control of blood pressure with the nitrates versus halothane during a standardized anesthetic. Twenty-one patients participated in the study, and all had the following: a radial arterial catheter, peripheral venous catheter, 7F pulmonary artery catheter, and Baim coronary sinus flow catheter. The study was carried out in the prebypass period beginning with awake measurements of baseline parameters, and ending after median sternotomy. The patients were divided into three groups: group 1 received an infusion of NTG; group 2 received an infusion of ISDN; and group 3, the control, received neither nitrate, but halothane was added to control hemodynamics. Measurements were made at the following time intervals: (1) baseline; (2) after 5 minutes of the nitrate infusions while awake (groups 1 and 2); (3) after induction of anesthesia, laryngoscopy, and intubation; and (4) after median sternotomy. In groups 1 and 2, the nitrates were infused at 0.1 mg/kg/h for 5 minutes. Thereafter, blood pressure control and treatment of episodic hypertension were achieved by alteration of the rate of nitrate infusions, or, in group 3, by 0.5% to 2% of inspired halothane.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

The repair of identified large DNA adducts induced by 4-nitroquinoline-1-oxide in normal or xeroderma pigmentosum group A human fibroblasts, and the role of DNA polymerases alpha or delta.

4-Nitroquinoline-1-oxide (4NQO) reacts with DNA primarily at the N2 and C8 of guanosine, with a small percent of reaction at the N6 of adenosine. In human cells it has been unclear whether or not all 4NQO-induced adducts are removed by a nucleotide excision repair mechanism. In this paper we demonstrate that the inhibitor of DNA polymerases alpha and delta, aphidicolin, blocks the repair of all 4NQO adducts. Hence excision repair must operate on all of these lesions. After 4NQO the residual excision repair seen in a xeroderma pigmentosum group A cell line virtually totally defective in UV repair was 40-60% of that in normal cells. Therefore there must be some differences between the excision repair operating on UV as opposed to 4NQO-induced DNA damage.

4-Nitroquinoline-1-oxide↗

PubMed1989

A comparison of the caregiving networks of dependent elderly individuals who are lucid and those who are demented.

Individuals who were demented were cared for mostly by members of the immediate household whereas those who were lucid received primarily extra-household assistance. Demented persons also received fewer hours of care from outside the household and from formal providers. It is argued that in cases of dementia, the household is likely to be the key unit of caregiving and adaptation. Implications of household insularity are discussed.

Aged↗

PubMed1989

Distribution of a prolactinlike material in human eccrine sweat glands.

Because prolactin has been implicated in the transport of electrolytes in several mammalian tissues, we have looked for the presence of prolactin in human eccrine sweat glands where a primary isotonic secretion, rich in sodium chloride, is produced and subsequently modified by recovery of some sodium and chloride in excess of water. Sweat glands were microdissected from skin biopsies and then fixed overnight in phosphate-buffered 4% formaldehyde. The fixed tissue was dehydrated (to 95%) in ethanol and then embedded in glycol methacrylate. Sections were cut (5 microns) and immunostained with antihuman prolactin (NIDDK IC2) and the specifically-bound antibody was visualized using a biotinylated second antibody and Vector ABC reagents. Prolactinlike immunoreactivity was localized in the clear cells of the secretory coil and, to a much lesser extent, in the basal layer of duct cells. In many of the clear cells, the immunoreactive material appeared as a lateral strip and occasionally, in favorable sections, as a horseshoe of reaction product a few microns in from the apical and lateral membranes. In a subset of clear cells, with more euchromatic nuclei and a long, thin cellular profile, the immunostaining was more intense and was localized in a more juxtanuclear position. Controls for endogenous peroxidase, and those using normal serum or antihuman prolactin serum preabsorbed with purified human prolactin, gave no peroxidase localization in the tissue. These results are important because 1) they represent the first demonstration of prolactin or a prolactinlike substance in the sweat gland, 2) the prolactinlike material was localized to clear cells that are thought to be responsible for much of the fluid secretion, 3) the necessity for prolactin or pituitary extract in primary cultures of sweat gland epithelium is potentially explained, although not fully understood, and 4) it means that further studies concerned with the possible influence of prolactin on ion transport in the sweat gland are warranted.

Humans↗