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Biomedical subjects

J K Murphy

Publications and source records attributed to J K Murphy.

At least 37 records · Page 2Linked to original sources
PubMed1992

Ethnicity, pressor reactivity, and children's blood pressure. Five years of observations.

During the 5 years of this investigation, resting blood pressure and pressor reactivity were measured in 292 white children and 46 black children in 1987, 1988, 1989, and 1991. In 1987, all children were in the third grade; in 1991, the children were in the seventh grade. Reactivity was assessed with a standardized psychological stressor, a television video game. Children displayed significant stability of absolute blood pressure and heart rate reactivity between grades 3 and 7. At all examinations, black children demonstrated blood pressure reactivity that was significantly greater in magnitude (both absolute level and change from resting measurements) than that of white children. Black children exhibited significantly greater heart rate reactivity only when defined as change from the resting measurements; absolute levels of heart rate reactivity were comparable for blacks and whites. For black children, blood pressure reactivity in 1987 was the strongest predictor of resting blood pressure (both systolic and diastolic) in 1991. Among white children, resting blood pressure was the strongest predictor of future resting blood pressure. Further research is needed to determine if ethnic differences in children's pressor reactivity are associated with ethnic differences in the prevalence of hypertension.

Aging↗
PubMed1991

Whether to measure change from baseline or absolute level in studies of children's cardiovascular reactivity: a two-year follow-up.

Blood pressure and heart rate were measured at rest and during a television video game in 399 healthy children. At the first assessment, children were in third grade and at the 2-year follow-up, they were in fifth grade. Children were classified according to race (black/white), gender (boy/girl), body mass index (light/heavy), and video game performance (low score/high score). Correlational analysis indicated that irrespective of the classification variable, absolute reactivity values, e.g., a heart rate of 110 bpm, tended to be more stable than change reactivity values, e.g., a heart rate change of 10 bpm. The greater stability of absolute values was most pronounced with systolic blood pressure. Absolute values were at least as stable as resting values and frequently demonstrated greater stability. Mean and maximal reactivities were correlated comparably. We conclude that children's reactivity is a stable characteristic and that, unless indicated by a priori hypotheses, the use of absolute values is preferable to the use of change values.

Arousal↗
PubMed1991

Polycythaemia and neuroblastoma.

The treatment of primary proliferative polycythaemia (polycythaemia rubra vera) may include radioactive phosphorus (P32) in conjunction with venesection. Acute leukaemia or carcinoma can be associated with the use of P32. We present a case of primary proliferative polycythaemia treated by repeat venesection together with P32 whose follow-up was complicated by the development of malignant neuroblastoma.

Bloodletting↗
PubMed1991

Stability of ethnic differences in children's pressor responses during three annual examinations.

In this study, 395 healthy children had blood pressure and heart rate measured both at rest and during a stressful video game. Identical measurement procedures were used for three annual examinations. Consistently, black children demonstrated significantly greater pressor responses than white children. In view of the greater prevalence of hypertension among black adults than white adults, these data suggest that blacks exhibit hemodynamic irregularities well before the onset or diagnosis of hypertension.

Black People↗
PubMed1991

Endothelin in human brain and pituitary gland: comparison with rat.

To investigate the physiological roles of endothelin (ET) in the brain and pituitary gland, the presence of immunoreactive (ir) ET and ET receptors was studied by radioimmunoassay and receptor assay in humans and rats. ir-ET concentrations in human brain (6-10 fmol/g of wet weight) were comparable with the levels in the rat brain (5-9 fmol/g of wet weight). Higher concentrations of ir-ET were found in human pituitary glands (147 +/- 30 fmol/g of wet weight, mean +/- SEM) and rat posterior pituitary lobes (88 +/- 26 fmol/g of wet weight). Fast protein liquid chromatography (FPLC) showed that the ir-ET in human hypothalamus and brainstem was mainly ET-1, while the ir-ET in human pituitary was mainly ET-3. FPLC of the whole rat brain extract showed a larger peak in the position of ET-3 and a smaller peak in the position of ET-1. Receptor assay showed that [125I]ET-1 binding sites were present in very large numbers in all five human brain regions and four rat brain regions examined but were much less abundant in the human pituitary. ET mRNA was detected by Northern blot hybridization in human pituitary but not in human hypothalamus. These findings are in accord with the possibility that ET acts as a neurotransmitter, neuromodulator, or neurohormone.

Animals↗
PubMed1991

Subacute cutaneous lupus erythematosus--the annular variant. A histological and ultrastructural study of five cases.

Subacute cutaneous lupus erythematosus is an uncommon, non-scarring variant of lupus erythematosus which has received scant attention in the pathology literature. Its recognition as a distinct entity is important, as, although mild systemic features may be associated, there is characteristically a relative absence of life-threatening renal or central nervous systemic involvement. Subacute cutaneous lupus erythematosus may be clinically sub-divided into the more common annular and the rarer papulosquamous (psoriasiform) variants. A clinicopathological study of five cases of the annular variant is presented with a review of the literature. We highlight the histological and ultrastructural appearances. Discriminatory features from the other variants of lupus erythematosus and additional conditions with which it may be confused, including lichen planus and acute graft-versus-host disease, are discussed.

Adult↗
PubMed1991

Children's cardiovascular reactivity: stability of racial differences and relation to subsequent blood pressure over a one-year period.

After measuring blood pressure and heart rate at rest and during a video game procedure in 477 children enrolled in 3rd grade, 434 (91%) children had these measurements repeated a year later in 4th grade. Black children demonstrated greater blood pressure and heart rate reactivity than White children in both years, and an increase in heart rate reactivity from 3rd to 4th grade. Gender effects were inconsistent. Systolic and diastolic blood pressures during the video game were more highly correlated from year-to-year than were the resting measures. Regression analysis indicated that systolic reactivity was significantly related to subsequent systolic pressure at rest, particularly among Black girls. Diastolic reactivity was associated with subsequent resting diastolic pressure only among White children. Associations between reactivity and future blood pressure were independent of initial resting blood pressure. This study suggests that cardiovascular reactivity to psychological stress may be one important factor in future level of blood pressure and that the increased heart rate reactivity of Black children may be associated with the prevalence of hypertension among Black adults.

Black or African American↗
PubMed1991

Endothelin in human brain and pituitary gland: presence of immunoreactive endothelin, endothelin messenger ribonucleic acid, and endothelin receptors.

The presence of immunoreactive (IR) endothelin, endothelin mRNA, and endothelin receptors in human brain and pituitary gland has been studied by RIA, Northern blot hybridization, and receptor assay. IR endothelin was detected in all five brain regions examined (cerebral cortex, cerebellum, brain stem, basal ganglia, and hypothalamus) (6-10 fmol/g wet wt) and spinal cord (22 +/- 6 fmol/g wet wt, n = 7, mean +/- SEM). Higher concentrations of IR endothelin were found in the pituitary gland (147 +/- 30 fmol/g wet wt). Fast protein liquid chromatographic analysis of the IR endothelin in pituitary gland showed a large IR peak in the position of endothelin-3 and a smaller peak in the position of endothelin-1, whereas IR endothelin in the hypothalamus and brain stem was mainly endothelin-1. Endothelin messenger RNA was detected by Northern blot hybridization in the pituitary but not in hypothalamus. The receptor assay showed that 125I-endothelin-1 binding sites were present in large numbers in all five brain regions but were much less abundant in the pituitary gland. Binding capacity and dissociation constant were 5052 +/- 740 fmol/mg protein and 0.045 +/- 0.007 nM in brain stem and 963 +/- 181 fmol/mg protein and 0.034 +/- 0.009 nM in hypothalamus. In the pituitary gland, there were two classes of binding sites for endothelin with dissociation constants of 0.059 +/- 0.002 nM (binding capacity = 418 +/- 63 fmol/mg protein) and 0.652 +/- 0.103 nM (binding capacity = 1717 +/- 200 fmol/mg protein). Endothelin-1, -2 and -3 were almost equipotent in displacing the binding (IC50 approximately 0.04 nM). These findings are in accord with the possibility that endothelin acts as a neurotransmitter, neuromodulator or neurohormone in man.

Aged↗
PubMed1991

Investigation and characterization of receptors for pituitary adenylate cyclase-activating polypeptide in human brain by radioligand binding and chemical cross-linking.

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a novel peptide of hypothalamic origin which increases adenylate cyclase activity in rat anterior pituitary cell cultures. The 38-amino acid peptide shows a close sequence homology to vasoactive intestinal peptide (VIP). Binding sites for PACAP in membranes from postmortem human brain tissue were studied using [125I]PACAP27 as the radioligand. High specific binding sites (amount of specific binding measured at 0.25 nM [125I]PACAP27 in femtomoles per mg protein +/- SEM; n = 4) were present in hypothalamus (344.5 +/- 13.0), brain stem (343.0 +/- 29.3), cerebellum (292.0 +/- 21.1), cortex (259.6 +/- 19.8), and basal ganglia (259.2 +/- 50.3). Specific binding sites in pituitary, although present, were less abundant (35.0 +/- 8.9). Binding of [125I]PACAP27 was reversible and time, pH, and temperature dependent. Despite the homology with VIP, VIP was a poor inhibitor of [125I]PACAP27 binding (IC50, greater than 1 microM) compared with PACAP27 (IC50, 0.5-1.3 nM) and PACAP38 (IC50, 0.2-1.3 nM). Scatchard plots of [125I]PACAP27 binding showed the presence of both high and lower affinity sites. Chemical cross-linking of PACAP-binding sites revealed that [125I]PACAP27 was bound to polypeptide chains of 67,000 and 48,000 mol wt. Thus, we have demonstrated the presence of PACAP-specific receptors in human brain which are not VIP receptors. This opens the possibility of PACAP functioning as a novel neurotransmitter/neuromodulator in human brain.

Brain↗
PubMed1990

A comparison of two automated monitors in the measurement of blood pressure reactivity. Trials of Hypertension Prevention Collaborative Research Group.

Cardiovascular reactivity is the change in blood pressure, pulse, and other parameters of cardiovascular function in response to a challenging task. During the conduct of cardiovascular reactivity protocols, researchers frequently use automated blood pressure devices to measure blood pressure reactivity. However, the accuracy of automated devices in measuring blood pressure reactivity is unknown. To investigate the accuracy and precision of the Dinamap 1846 SXP and the VitaStat 2600B in the measurement of blood pressure reactivity, we compared blood pressure reactivity recorded by the VitaStat and Dinamap with that obtained by observers using a conventional mercury sphygmomanometer. At three sites, 159 normotensive subjects performed the same task twice, once with blood pressure reactivity measured by the manual observers and once by the VitaStat (n = 79) or Dinamap (n = 80), with the order determined at random. Ratios (VitaStat/Dinamap) of aggregate within-person variance for baseline and task, systolic and diastolic blood pressures ranged from 1.53 to 4.93 (all P < 0.01), suggesting that the Dinamap has better precision than the VitaStat. For both diastolic and systolic blood pressure reactivity and for both types of automated devices, the mean differences in blood pressure reactivity between manual and automated measurements were small (range, -1.8 to 0.8 mm Hg). However, the VitaStat versus manual scatter plot of diastolic blood pressure reactivity showed greater dispersion (correlation coefficient r = 0.16, P = 0.15) than the Dinamap versus manual scatter plot (r = 0.36, P = 0.001). For systolic blood pressure reactivity, the VitaStat versus manual and Dinamap versus manual scatter plots were similar. Our data indicate that the Dinamap is superior to the VitaStat in the measurement of blood pressure reactivity. The substantial performance differences between the VitaStat and Dinamap suggest that other automated blood pressure monitors must be evaluated prior to use in cardiovascular reactivity studies.

Adult↗
PubMed1990

Demonstration of Epstein-Barr virus in primary brain lymphoma by in situ DNA hybridisation in paraffin wax embedded tissue.

Tumour tissue from 29 patients with primary brain lymphoma was reviewed to determine if there was an aetiological association between Epstein-Barr virus and polyclonal and monoclonal lymphoproliferations. The morphology and immunophenotype in 24 patients for whom paraffin wax embedded tissue was available were studied. A high grade pleomorphic tumour morphology with plasmacytoid features was seen in 13 tumours. Because of the large number of pleomorphic lymphomas, all tumours were examined for the presence of the Epstein-Barr virus genome using in situ DNA hybridisation. A panel of three biotinylated probes to different sequences in the Epstein-Barr virus genome was used. Positive hybridisation with one or more probes was shown in tumours from 11 patients. The remaining tumours gave no hybridisation signal. There was no correlation between positive hybridisation and morphological subtype or clinical outcome.

Adolescent↗
PubMed1990

Primary lymphoma of the bladder: a clinicopathological study of 3 cases.

Primary involvement of the bladder by lymphoma is rare but is associated with a favourable prognosis if diagnosed early and treated appropriately. The clinicopathological features of 3 cases of primary, non-Hodgkin's lymphoma of the bladder are described. This small study suggests a better prognosis with a favourable histological grade and an uncomplicated lymphoma confined to the bladder. We emphasise the value of aggressive treatment of the tumour.

Aged↗
PubMed1990

Aerobic fitness and the diurnal rhythm of blood pressure in adolescents.

We examined the effects of aerobic fitness and race on the diurnal rhythm of blood pressure of 175 healthy adolescents who performed a cycle ergometer maximal exercise test while oxygen consumption was measured. A median split of maximum oxygen consumption for boys and girls separately classified them as either "more-fit" or "less-fit" subjects. Ambulatory blood pressure recordings were also performed, and the data were analyzed for means while subjects were awake and asleep. Less-fit black boys had higher systolic pressures than more-fit black boys while awake (124 vs. 115 mm Hg; p less than 0.009) and asleep (117 vs. 108; p less than 0.001). Less-fit black boys also had higher systolic pressures than less-fit white boys while awake (114; p less than 0.002) and asleep (105; p less than 0.001), and they had higher systolic pressures than more-fit white boys while asleep (105; p less than 0.01). Less-fit black girls had higher systolic pressures than more-fit black girls while awake (116 vs. 109; p less than 0.004) and asleep (109 vs. 100; p less than 0.001). Less-fit black girls also had higher diastolic pressures than more-fit black girls while awake (71 vs. 66; p less than 0.002) and asleep (66 vs. 61; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Effects of doxepin on withdrawal symptoms in smoking cessation.

In a double-blind study, 15 cigarette smokers self-monitored 10 withdrawal symptoms. For the first 21 days (baseline), subjects received doxepin hydrochloride, up to 150 mg/day, or inert medication while continuing to smoke. On day 22, they were instructed to stop smoking; medication was continued. Withdrawal symptoms on the first 28 days of treatment (baseline and 7 days of attempted cessation) were analyzed. During cessation, subjects taking doxepin reported significantly less craving for cigarettes. Results from this study and others suggest that antidepressants may attenuate the severity of symptoms during withdrawal from addictive substances.

Adult↗
PubMed1990

Self-reports of salt intake by 10- to 18-year-olds: relationship to urinary sodium excretion.

Our data indicated that self-reports of consumption of salty foods by children and adolescents were associated with 24-hour urinary sodium excretion. Specifically, youths 10 to 18 years of age who selected a poster depicting high-sodium foods excreted significantly more sodium than youths who selected a poster depicting low-sodium foods. Future research is needed to refine simplified self-report measures, to corroborate the validity of the measures, and to extend the studies to other samples, e.g., younger children.

Adolescent↗
PubMed1990

The validity of children's self-reports of physical activity: a preliminary study.

Ninety-two healthy children provided self-reports of their physical activity. Self-reports were based upon posters depicting children performing typical childhood activities and were validated by measured oxygen uptake during maximal cycle ergometry. Results indicated that when children were classified as sedentary or active by their poster selection, active children had significantly greater oxygen uptake than sedentary children. These results, while preliminary, are the first to indicate that children's self-reports can provide a valid index of maximal oxygen uptake, the 'gold standard' of aerobic fitness.

Adolescent↗
PubMed1989

Morphologic and immunophenotypic characterization of primary brain lymphomas using paraffin-embedded tissue.

Primary lymphomas of the brain constitute about 1% of all primary intracranial neoplasms, but recent studies suggest an increasing incidence. Most cases are associated with an immunosuppressed state. We reviewed 29 cases of primary brain lymphoma from the Yorkshire Health Authority Region between 1970 and 1988 and found a striking increase in incidence over this period. No overt evidence of immunosuppression was found in any case. All were non-Hodgkin's in type and were classified morphologically using Kiel criteria and immunophenotypically using a panel of antibodies. Cryo-preserved tissue was available in five cases for parallel immunophenotyping. The majority of tumours were high-grade lymphomas together with three of lymphoplasmacytoid type. Thirteen tumours showed a striking pleomorphic morphology with plasmacytoid features. A reactive, predominantly perivascular monomorphic T-cell population was seen in all tumours. Most tumours were of B-cell lineage. No cases of Hodgkin's disease, T-cell or histiocytic lymphoma were present. Light chain restriction was present in only 46% of cases. The results of tumour immunophenotyping on cryostat sections were comparable with those from paraffin blocks. Our study emphasizes the value of a panel of antibodies reactive in paraffin-embedded tissue, allowing simultaneous evaluation of morphology and immunophenotype, and suitable for small biopsies received from stereotactic procedures.

Adolescent↗