Biomedical subjects

B Falkner

Publications and source records attributed to B Falkner.

At least 91 records · Page 5Linked to original sources

PubMed1982

Changes in R wave amplitude during aerobic exercise stress testing in hypertensive adolescents.

The change in R wave amplitude during progressive aerobic exercise was studied in hypertensive adolescent boys. A comparable control group consisted of normotensive adolescent boys matched for age, body size and race. Twenty-four normotensive and 22 hypertensive subjects exercised to exhaustion on a treadmill utilizing the Bruce protocol. Blood pressure and heart rate were monitored during exercise and recovery. The change in R wave amplitude in a lead V5 electrocardiogram was determined at each level of exercise. The normotensive group demonstrated a progressive increase in systolic pressure, heart rate and rate-pressure product (heart rate x systolic pressure) during exercise and a progressive decrease in R wave amplitude with a significant correlation of R wave change versus the cardiac response variable (p less than 0.001). Hypertensive subjects manifested a greater increase in systolic pressure, heart rate and rate-pressure product during exercise with no decrease in R wave amplitude until the exercise end point. The difference in R wave response to progressive exercise in the two groups was significant (p less than 0.01). A variation in myocardial function in hypertensive adolescents as demonstrated by a difference in R wave response to exercise may reflect a level of peripheral vascular resistance greater than that of normotensive control subjects.

Adolescent↗

PubMed1982

Effect of hospitalization versus placebo in hypertensive adolescents.

The effect of hospitalization on blood pressure was determined in 31 adolescents admitted to the hospital for evaluation of mild hypertension. All were diagnosed as having primary hypertension. There was a progressive decline of systolic (p less than 0.001) and diastolic pressure (p less than 0.001) during hospitalization. After discharge the blood pressure returned to the preadmission level. In 32 ambulatory adolescents with primary hypertension who were treated with placebo for 4 weeks, there was no decline in blood pressure. These observations suggest that hospitalization in hypertensive juveniles, as well as adults, results in a decrease in blood pressure. These findings also suggest that initiating and adjusting antihypertensive therapy in such patients may be confounded by the independent decrease in blood pressure due to hospitalization.

Blood Pressure↗

PubMed1982

Dynamic and biochemical responses to single and repeated doses of clonidine during dynamic physical activity.

Beta-adrenoceptor blockade increases serum K, which may be related to renin inhibition, hypoaldosteronism, and exercise-induced skeletal muscle release of serum K. We report on the dynamic and biochemical response to clonidine (C) after single (S) 0.2-mg and repeated (R) 0.1-mg bid doses of C to six normal subjects at rest, 2 hr after dosing and immediately before dynamic physical activity (DPA) on a treadmill, and at peak activity and 2 hr after DPA. Blood pressure (BP), heart rate (HR), plasma renin concentration (PRC), aldosterone (ALD), serum K, epinephrine (E), and norepinephrine (NE) were measured in standing subjects before and 2 hr after placebo or C (S or R), at peak DPA, and 2 hr after exercise. K, BP, and HR were also determined during all stages of DPA. Results show a parallel rise in K at peak over rest after C (S or R) and after placebo. NE, E, and PRC decreased after 1 wk of C (P less than 0.01), but the fall of ALD was only slight. The fall in NE at rest suggested a relationship to the decrease in systolic BP and rate pressure product after 1 wk on C. With DPA there is a normal yet smaller increase in systolic BP and also a smaller rise in HR with S- and R-dose C. There is no adverse rise in K in C-treated subjects during DPA.

Aldosterone↗

PubMed1982

Effectiveness of centrally acting drugs and diuretics in adolescent hypertension.

The effectiveness and tolerance of a centrally acting antihypertensive agent (clonidine) was compared to that of a diuretic (hydrochlorothiazide) in treatment of adolescents with essential hypertension. After a phase on placebo 29 adolescents with fixed primary hypertension were randomly assigned, double blind, to one of two treatment groups. Active therapy was initiated at a low dose (0.1 mg clonidine b.i.d. or 24 mg hydrochlorothiazide b.i.d.) for 12 wk. In those in whom treatment goals for blood pressure control had not been reached, the dose was increased (clonidine to 0.2 mg and hydrochlorothiazide to 50 mg) for 12 wk. In the clonidine-treated group there was a reduction during low-dose therapy in systolic (P less than 0.05) and diastolic pressure (P less than 0.01) and heart rate (P less than 0.01). With low-dose diuretic therapy there was a reduction in systolic pressure only (P less than 0.05). Linear growth patterns were normal for both groups, but there was a reduction in serum potassium in the diuretic group (P less than 0.001). Of the two drugs investigated the centrally acting clonidine was more effective in blood pressure control (85%) than the diuretic (40%).

Adolescent↗

PubMed1982

Biochemical and dynamic responses to single and repeated doses of methyldopa and propranolol during dynamic physical activity.

Our purpose was to describe changes in potassium disposition with antirenin antihypertensives during dynamic physical activity in normal subjects receiving methyldopa and propranolol. Before the study, 2 hr after dosing and coincident with immediate preexercise on treadmill (at graded increases of exercise), and 2 hr after exercise, blood was sampled for determination of potassium, renin, aldosterone, and catecholamine levels. Blood pressure and heart rate were measured. The results demonstrate no greater increase in potassium after single or multiple doses of methyldopa than after placebo. After the first dose of propranolol there was a greater rise in potassium over that with placebo, but it was not observed after multiple doses, which may be related to the low doses. There were minor, but significant, changes in norepinephrine, renin, and systolic pressure with multiple-dose methyldopa and in renin, heart rate, and systolic and diastolic pressure with propranolol. Overall, the adrenergic responses to exercise win methyldopa and propranolol were biochemically altered rather than functionally impaired. The latter is related to dose and the underlying age and state of health of our subjects. Methyldopa (or clonidine) may be useful in patients with hypertension who exercise and are predisposed to pertubations in potassium disposition.

Adult↗

PubMed1982

Potassium disposition and neuroendocrine effects of propranolol, methyldopa and clonidine during dynamic exercise.

In order to determine the changes in potassium disposition with antirenin, antihypertensives during dynamic physical activity, a double-blind placebo controlled study was undertaken using normal volunteers receiving placebo or single and multiple dose clonidine, methyldopa and propranolol 0.2 mg. followed by 0.1 mg. bid x 7 days, 500 mg. followed by 250 mg. bid x 7 days or 80 mg. followed by 40 mg. bid x 7 days, respectively. Prior to study, 2 hours post dosing and coincident with immediate pre-exercise on treadmill, at graded increases of exercise and 2 hours post exercise (approximately 4 hours post dosing), blood was sampled for potassium, renin concentration, aldosterone and catecholamines. Blood pressure (BP) and heart rate (HR) were measured. The results demonstrate no greater increase in potassium over placebo with single or multiple dose clonidine or methyldopa. Following the initial dose of propranolol, 80 mg., there was a statistically greater rise in potassium over that seen with placebo but not observed with multiple dose. This may be related to the low multiple dose regimen. There were minor but significant changes in norepinephrine, renin and systolic pressure with multiple dose clonidine and methyldopa and in renin, heart rate and systolic and diastolic pressure with propranolol. Overall, the adrenergic responses, to exercise with methyldopa and propranolol are more biochemically altered than functionally impaired, yet the latter is related to dose and the underlying age and state of health of the group being studied.

Aldosterone↗

PubMed1982

The pharmacodynamic effectiveness of metoprolol in adolescent hypertension.

The effectiveness of metoprolol in achieving blood pressure control was studied in 16 hypertensive adolescents. The hypertensive included two insulin dependent diabetics, four patients with renal disease, and ten adolescents with essential hypertension. Dose range was 100-200 mg/day for 3-12 months. Significant reductions on metoprolol therapy were achieved for systolic blood pressure (SBP) (P less than 0.001), diastolic blood pressure (DBP) (P less than 0.001), and heart rate (HR) (P less than 0.001). Side effects that had been present in previous therapy were absent. On metoprolol therapy the hyperkinetic cardiovascular response to mental stress was improved for SBP and HR. Exercise stress testing also resulted in a reduced SBP and HR, while endurance capacity was unimpaired. Metoprolol is effective in adolescent hypertension with negligible side effects.

Adolescent↗

PubMed1981

Growth hormone release in hypertensive adolescents treated with clonidine.

The release of the growth hormone in the basal state and in response to strenuous exercise was studied in a group of 15 hypertensive adolescents receiving clonidine therapy and in a control group of 17 untreated adolescents of which ten were hypertensive volunteers and seven were health normotensive volunteers. Mean basal growth hormone in clonidine-treated adolescents was 2.8 +/- 0.50 S.E.M. ng/ml, compared to 2.7 +/- 0.48 ng/ml in untreated adolescents. Following exercise stimulation, mean growth hormone was 14.8 +/- 3..1 S.E.M. ng/ml in the treated group and 13.5 +/- 2.8 ng/ml in the untreated group. Growth hormone release is regulated by alpha-adrenergic receptor stimulation. Clonidine acts centrally by alpha-adrenergic stimulation. However, this study demonstrates no effect of chronic clonidine therapy on growth hormone release.

Adolescent↗

PubMed1981

A harmonic analysis of cardiac response of normotensive and hypertensive adolescents during stress.

In this paper, a statistical analysis is applied to the systolic (SBP) and diastolic blood pressure (DBP) and heart rate (HR) data of 23 normotensive (NT) and 24 hypertensive (HT) adolescents who underwent a 10-minute mental stress regimen. Readings were measured at one-minute intervals. The harmonic time series analysis is based on the data of an eight-minute interval of the stress phase. The NT group established a statistically significant (p less than .05) rhythmic variation described by a sinusoidal wave about a near pre-stress mean. The HT group exhibits for the three parameters a near constant response about a significantly elevated level. The consistent existence of a rhythmic pattern for the NT subjects under mental stress, in contrast to the constant response for the HT subjects, suggests that mental stress causes a change in the "natural" rhythmic pattern of cardiac response for the HT subject alone.

Adolescent↗

PubMed1981

Stress response characteristics of adolescents with high genetic risk for essential hypertension: a five year follow-up.

A group of 80 adolescents identified with blood pressure in the border-line range (90th to 95th percentile) have a follow-up of up to five years. Within this follow-up period 54 or 67% have progressed to a stage of sustained essential hypertension (BP greater than 95th percentile). Characteristics of this population with a very high progression rate to EH are: 1) Identification of borderline hypertension in adolescence. 2) Uniformly strong family history of EH and 3) A high cardiovascular response to mental stress.

Adolescent↗

PubMed1980

Plasma renin and occurrence of hypertension in children with burn injuries.

Children with thermal injuries have an unusually high incidence of hypertension during the course of their postinjury care. This study investigates the activity of the renin angiotensin system during the postinjury period. Sustained hypertension occurred in three of 11 children studied. All three cases demonstrated markedly elevated plasma renin levels (greater than 2IRU x 10(4)). Two of five children with episodes of hypertension also demonstrated abnormally high plasma renin. No normotensive patients had markedly elevated renin levels. The mechanism directing elevated renin secretion may be related to changes in regional blood flow in addition to the stimulus of increased catecholamine activity. A markedly elevated plasma renin may be predictive of the development of hypertension.

Age Factors↗

PubMed1980

Dynamic exercise response in hypertensive adolescent on clonidine therapy: clonidine therapy in adolescent hypertension.

The cardiovascular response to dynamic exercise is compared in 16 normotensive control adolescents (C), 15 untreated hypertensive (H) adolescents, and 14 hypertensive adolescents on clonidine therapy (HRx) for blood pressure control. All subjects exercised to exhaustion (heart rate (HR) = 200) on a treadmill by Bruce protocol. Blood pressure and HR were monitored during exercise and recovery. Systolic pressure was greater in H and HRx and than C at baseline, exercise, and recovery (P less than 0.01) as was the product of systolic blood pressure times heart rate (SBP X HR). Diastolic blood pressure (DBP) was greater in H and HRx at base line but decreased in all subjects (C, H, and HRx) during vigorous exercise. Our results indicate that H and HRx adolescents have higher SBP and HR at rest and exercise consistent with a hyperkinetic circulatory state; DBP response to exercise is normal in H adolescents; and, clonidine in HRx lowered baseline HR and blood pressure but did not alter a normal exercise response.

Adolescent↗

PubMed1978

Hypertension in children with burns.

Hypertension has been observed to occur frequently in children with burns. In a series of children admitted to the St. Agnes Burn Treatment Center, sustained systolic and diastolic hypertension occurred in 31.5%, and 57.4% of the children demonstrated episodic periods of hypertension which were unsustained. The only clinical finding which significantly correlated with the hypertension was the presence of tachycardia, which persisted into the late healing phase of the thermal injury. Hypertension was more prevalent at younger ages. However, there was no other correlation of the development of hypertension with sex, race, or extent of thermal injury. The development of hypertension in itself did not worsen the prognosis for survival in the cases presented in this series. Possible pathogenic mechanisms which result in hypertension (elevated catecholamines, norepinephrine, renin secretion) are discussed.

Adolescent↗

PubMed1977

Immune complex glomerulonephritis in a case of retroperitoneal fibrosis.

The nephropathology associated with retroperitoneal fibrosis has been commonly related to compression of the ureters and hydronephrosis. This assumption has been made without the use of immunofluorescent microscopy and electron microscopy. The authors studied renal tissue from a patient with retroperitoneal fibrosis by light microscopy, immunofluorescent microscopy and electron microscopy. In addition to the gross and microscopic changes of obstructive nephropathy, histologic findings of glomerular immune-complex deposition were also present. It is postulated that in some cases of retroperitoneal fibrosis, destruction may be mediated by both obstructive and immunologic processes.

Adult↗

PubMed1977

Renal histopathological changes in a child with Laurence-Moon-Biedl syndrome.

This report describes a case of Laurence-Moon-Biedl syndrome identified in a 24-month-old boy. Significant renal involvement was present with right-sided vesicoureteral reflux, cystocele, urinary tract infections, and growth arrest of the right kidney. After the development of hypertension a left renal biopsy was performed to determine if bilateral renal disease was present. Histopathological and ultrastructural changes in the left kidney are described. These changes appear to be unrelated to pyelonephritis or hypertension and to be most consistent with the nephropathy of Laurence-Moon-Biedl syndrome.

Humans↗

PubMed1976

Subpopulations of peripheral lymphocytes in juvenile diabetes.

Subpopulations of peripheral lymphocytes were studied in 26 children with insulin-treated juvenile diabetes and in 27 control children of comparable age. T-lymphocytes were quantitated by spontaneous rosette-formation with sheep erythrocytes and B-lymphocytes by indirect immunofluorescence with the use of monovalent, fluorescein-labeled rabbit antiserum specific to the heavy chains of human IgG IgM, or IgA. No significant quantitative difference in subpopulations of the peripheral lymphocytes, T-cells, and B-cells with IgG, IgA, or IgM markers found between children with juvenile diabetes and the control group, although the B-lymphocytes with IgG or IgA markers tended to be higher and those with IgM markers lower in the diabetic than in the control group.

Adolescent↗

PubMed1975

Bacteriuria in the catheterized patient. Cystitis or pyelonephritis?

Seventy-two patients with indwelling urethral catheters had urine specimens cultured to detect bacteriuria. Bacterial sediments were examined to find the source of the bacteria, with use of an antibody immunofluorescence (IF) technique. Antibody coating demonstrated by fluorescence was considered evidence for pyelonephritis. In cystitis, the bacteria did not fluoresce. Repeat culture and immunofluorescence studies were done 3 to 18 week later. One third of the patients had a urinary infection. Two (13%) of the patients catheterized for one day and 17 (55%) catheterized four or more days had appreciable bacteriuria. One patient catheterized less than three days had positive IF, while 5 patients (16%) catheterized four or more days had positive IF. Only two of the ten patients observed, with an initial infection, had sterile urine on follow-up culture. On follow-up study, of the four patients with bacteriuria of renal origin, one showed a sterile urine, two had cystitis, and one still had pyelonephritis.

Adult↗

PubMedDate not supplied

Cardiovascular response to mental stress in normal adolescents with hypertensive parents. Hemodynamics and mental stress in adolescents.

The hemodynamic response to mental stress (mental arithmetic) was studied in adolscents with varying risk factors for essential hypertension (EH), One group (genetic) consisted of normotensive well adolescents who had at least one parentnt with EH. Another group (labile) consisted of adolescents with labile hypertension each of whom also had at least one pare with EH. The control population consisted of normotensive adolescents with a negative family history of EH. Subjects with labile hypertension demonstrated a sustained increase in systolic and diastolic pressure and heart rate during stress. This response was significantly different than the control population (P less than THE CONTROL POPULATION (P LESS THAN 0.001). The stress response of the normotensive genetic population was qualitatively similar to the group with labile hypertension and significantly different than the controls in diastolic pressure and heart rate (p less than 0.001, less than 0.02). Post-stress plasma catecholamines were higher in the labile hypertensive and genetic groups than in the control group. These findings demonstrate increased central nervous system mediated adrenergic activity and cardiovascular response in labile hypertension and also in some normotensive subjects with a genetic risk for hypertension.

Adolescent↗