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Biomedical subjects

S Blank

Publications and source records attributed to S Blank.

At least 37 records · Page 2Linked to original sources
PubMed1990

Early intervention in the context of foster care.

There may be a number of specific foster care models that would facilitate infant development. The important point is that the emphasis should shift from foster care as maintenance to foster care as active intervention. Several other recent developments in public policy and public opinion suggest that the time is ripe for such a change; the federal government has mandated provision of early intervention services for young children at risk, and there is renewed interest in breaking the cycle of disadvantage. At this point, we must deal with the reality of the large number of infants and young children who enter the foster-care system and who stay for substantial periods of time. This situation represents an opportunity for professionals and foster parents alike to play a crucial role in changing the potentially adverse course of development for many children. It is an opportunity too important to be lost.

Child Abuse↗
PubMed1989

Effect of hindlimb immobilization and recovery on compensatory hypertrophied rat plantaris muscle.

Compensatory hypertrophy of the rat plantaris muscle (PLT) was induced by ipsilateral gastrocnemius muscle ablation. Following 8 weeks (wks) of hypertrophy, hindlimbs were cast immobilized (HI) for 4 weeks after which weight bearing was unrestricted for 8 wks (recovery). Compensatory hypertrophy increased PLT wet weight/body weight ratio (83%), muscle fiber cross-sectional areas (1.5 to 2 fold), and the percent of slow oxidative (%SO) fibers (2 fold) in the experimental compared to the contralateral sham control muscle. PLT protein content and maximal activities of phosphofructokinase (PFK), mitochondrial glycerol phosphate dehydrogenase, and succinate dehydrogenase were unaltered with muscle hypertrophy. HI produced significant decreases in PFK activity (50%) and muscle fiber cross-sectional areas (50%) but did not significantly change the histochemical myofibrillar ATPase profile. Following remobilization, muscle weight/body weight ratio and maximal enzyme activities recovered to that of aged matched controls. Muscle fiber areas returned to pre-immobilization sizes but were approximately 25% smaller than aged matched control hypertrophy muscles. The %SO fibers in the hypertrophied muscle remained higher than controls but did not return to pre-immobilization values. These results indicate that biochemical and histochemical characteristics of hypertrophied rat PLT recover from HI during 8 wks of normal weight bearing similar to that of normal control muscle. However, the recovery time period was insufficient to allow complete compensation of fiber size to that of the age-matched control animals.

Animals↗
PubMed1989

The genes for beta-myosin heavy chain and glycogen phosphorylase are discoordinately regulated during compensatory growth of plantaris muscle in the adult rat.

It has been shown previously that compensatory hypertrophy of the plantaris muscle in adult rats can be induced by surgical removal of the synergistic gastrocnemius muscle. During hypertrophy, muscle transformation also occurs and there is a shift in the fiber type population of the muscle from fast to slow. Towards obtaining a better understanding of the molecular mechanisms controlling this process, we have carried out a kinetic analysis of the change in expression of two muscle-specific genes encoding the slow beta-heavy chain isoform of myosin and the muscle isoform of glycogen phosphorylase. This analysis indicated that significant increases (2-3 fold) in the steady-state levels of slow myosin heavy chain mRNA and protein did not occur until several weeks following ablation of the gatrocnemius muscle. Increases in slow fiber type paralleled the change in beta-myosin heavy chain expression. In contrast, the activity of phosphorylase, as well as the level of its corresponding mRNA, decreased approx. 1.5-2 fold shortly after (2-4 days) ablation of the gastrocnemius and levels remained low for at least several weeks. Significant changes in expression of these genes did not occur in plantaris muscle from sham operated contralateral legs. These studies indicated that changes in the expression of both genes was governed primarily by accumulation of their mRNAs. However, these genes were not coordinately regulated, indicating either that multiple control mechanisms regulate gene expression in this system or that the same controlling factor(s) regulates expression of these genes in temporally different ways.

Animals↗
PubMed1989

Biochemical characteristics of mammalian myocardia.

Selected biochemical parameters of the ventricular myocardium were compared among several orders of adult mammals with established differences in resting heart rate (cattle, 51 beats/min; swine, 68; canine, 107; rabbit, 256; guinea-pig, 273; rat, 355; mouse, 475). It was hypothesized that the biochemical character of mammalian myocardia is associated with the chronic functional demand on the muscle. Therefore, differences observed in the myocardial biochemical potential among the species could reflect differences in resting heart rate. Myocardia from smaller mammals with higher resting heart rate had significantly (P less than 0.05) higher maximal activities of citrate synthase, 3-hydroxyacyl-CoA dehydrogenase, lactate dehydrogenase (muscle/total), hexokinase and oxidation rates of glucose and palmitate than did larger mammals with lower resting heart rate. Maximal activities of phosphorylase and phosphofructokinase were more uniform across the animals. Correlation coefficients determined among average values of measured biochemical parameters and resting heart rate indicated that resting heart rate was closely associated with: citrate synthase (r = 0.86), 3-hydroxyacyl-CoA dehydrogenase (r = 0.93), ratio muscle/total lactate dehydrogenase (r = 0.89), hexokinase (r = 0.89), glucose oxidation (r = 0.88), and palmitate oxidation (r = 0.93). Significant correlations were observed among all of these parameters with the exception of citrate synthase vs. 3-hydroxyacyl-CoA dehydrogenase, and glucose oxidation vs. muscle/total lactate dehydrogenase. It was concluded that the oxidative capacity of mammalian myocardia was closely associated with resting heart rate, whereas the glycolytic potential of the myocardia was more uniform among the species.

Animals↗
PubMed1988

How common is white coat hypertension?

Twenty-one percent of 292 patients with untreated borderline hypertension (clinic diastolic blood pressures persistently between 90 and 104 mm Hg) were found to have normal daytime ambulatory pressures (defined from a population of normotensive subjects). These patients were defined as having "white coat" hypertension, and they were more likely to be female and younger, to weigh less, and to be more recently diagnosed than patients whose pressure was elevated both in the clinic and during ambulatory monitoring. Patients with white coat hypertension did not show a generalized increase of blood pressure lability, nor an exaggerated pressor response while at work. The phenomenon is more pronounced when blood pressure is measured by a physician than by a technician. In such patients, the pressor response may be relatively specific to the physician's office and lead to significant misclassification of hypertension.

Adult↗
PubMed1988

Biochemical characteristics of mammalian diaphragms.

Selected biochemical characteristics of diaphragm muscle were compared among several orders of adult mammals (cattle, swine, rabbit, guinea pig, rat, and mouse) with known differences in resting breathing frequencies (f, range = 15-138). Diaphragms from smaller animals had significantly higher citrate synthase (CS) and phosphofructokinase (PFK) activities and substrate oxidation rates than larger animals. Ranges of activities for CS and PFK were 93-27 and 58-39 mumol.g-1.min-1, respectively; and 34-5 and 19-2 nmol.g-1.min-1 for [U-14C]glucose (GLU) and [1-14C]palmitate (PAL) oxidation, respectively. The percent of native fast myosin (FM) isoforms was significantly different among groups. Mouse diaphragm had the highest % FM (88.6%), whereas the lowest values (7.5%) were observed in cattle diaphragm. Myosin ATPase (M-ATPase, pH 9.8) activity was significantly lower in cattle (0.06 mumol.mg protein-1.min-1) and swine (0.38 mumol.mg protein-1.min-1) diaphragm than in other mammals (range of 1.14-0.67 mumol.mg protein-1.min-1). Correlation coefficients determined among means of measured biochemical parameters and established values of f indicated that CS activity and substrate oxidation rates were significantly correlated with f (r = 0.92, 0.92, 0.86 for CS, GLU, PAL, respectively) and the % FM increased with f. M-ATPase (pH 9.8) was significantly correlated with % FM (r = 0.85), whereas PFK and M-ATPase activities were not closely associated with f. It was concluded that f in mammals is significantly correlated with the biochemical parameters of aerobic capacity and is associated with the percent of FM isoforms in the diaphragm.

Animals↗
PubMed1987

A quantitative analysis of the effects of activity and time of day on the diurnal variations of blood pressure.

The effects of activity and time of day on blood pressure (BP) were analyzed in 461 patients with untreated hypertension who wore a noninvasive portable BP recorder which took readings every 15 minutes for 24 hours. Patients recorded activity and location in a diary. The data were analyzed separately for two groups of patients: the 190 who stayed at home and the 271 who went to work. The effects of 16 different activities on BP were estimated by relating the BP to the associated activity and to the individual's clinic BP. Blood pressure was higher at work than at home, but the increment of BP for individual activities was similar in the two locations. The overall effect of activities on BP variability was computed using a one-way analysis of covariance model. For the patients who went to work this model accounted for 40% of the observed variation (R2) for systolic and 39% for diastolic BP. A similar model using time of day instead of activity accounted for 33% of variability in both systolic and diastolic BP. Combining activity and time of day was little better than activity alone (41% for both). After allowing for the effects of activity on BP, where sleep is one of the activities, there was no significant diurnal variation of BP. We conclude that there is no important circadian rhythm of BP which is independent of activity.

Adolescent↗
PubMed1986

Behavioral determinants of 24-hour blood pressure patterns in borderline hypertension.

Borderline hypertension is a heterogeneous condition; only a minority of patients will progress to fixed essential hypertension or suffer cardiovascular damage. Ambulatory blood pressure monitoring can detect the subgroup of borderlines with sustained blood pressure elevation outside the office setting and can also provide a measure of blood pressure variability. Patients in the former group may be at greatest risk for cardiovascular complications while the latter have been theorized to be at risk for progression to fixed hypertension. Evidence we have gathered utilizing ambulatory monitoring does not support the contention that there is a subgroup of borderline hypertensives with excessive blood pressure variability in natural settings. Such recordings have been of benefit in identifying patients with excessive pressor responses to office visits. Future studies employing ambulatory monitoring may be useful in the detection of clinically important subgroups of borderline hypertension.

Behavior↗
PubMed1984

Influence of exercise on the fiber composition of skeletal muscle.

Biopsy samples from the vastus lateralis muscle (VLM) of man were examined for fiber composition at rest and at selected intervals during prolonged exercise ranging in intensity from 40% to 75% of the total body maximal oxygen uptake (VO2max) and one-min bouts of exercise at 150% VO2max. Because of the heterogeneity of fibers in human VLM, studies were also completed where the effect of exercise on the fiber composition of the rat soleus muscle (SM) was examined. In some animals the SM from one hindlimb was removed 9 days prior to their being exercised after which the remaining SM was removed. Exercise reduced muscle glycogen in all experiments. In the studies with man, blood lactate exceeded 17 mmoles/l after the heavy exercise but was largely unchanged by endurance exercise. Colonic temperature of the exercised rats exceeded 40 degrees C. In studies where fibers were identified only as type I and type II, type II fibers in the VLM of all samples (16) taken at rest averaged 61.2 +/- 12.5% as compared to 59.0 +/- 12.0% after exercise (54 biopsy samples). In a second series of studies with man where the subtypes of type II fibers were identified, there were also no differences in fiber composition of the VLM after varying periods of exercise. Glycogen content and percent fiber composition were the same in right and left SM obtained from rested rats. Exercise (30 to 40 min) did not alter the fiber composition of the rat SM. These data demonstrate that the histochemically demonstratable myofibrillar actomyosin ATPase of skeletal muscle is not altered by a single exercise bout.

Adenosine Triphosphatases↗
PubMed1982

Blood pressure during normal daily activities, sleep, and exercise. Comparison of values in normal and hypertensive subjects.

Blood pressure (BP) readings were taken every 15 minutes using a noninvasive ambulatory BP recorder during 24 hours in 25 subjects with normal BP, 25 with borderline hypertension, and 25 with established essential hypertension. Readings were analyzed for four situations: (1) physician's office, (2) work, (3) at home, and (4) asleep. Treadmill exercise tests were also performed on a separate occasion with the Bruce protocol. The 24-hour recording in all three groups showed the highest BPs at work and the lowest during sleep. The situational BP changes were generally similar, but both hypertensive groups differed from normal subjects in that they showed consistently higher BPs in the physician's office than at home, whereas normal subjects showed a similar rise of systolic pressure to that of normal subjects. Pressures recorded in the physician's office gave good predictions of the average 24-hour pressure in normal and established hypertensive subjects, but not in the borderline group; in such patients, 24-hour monitoring may be of particular value in establishing the need for treatment.

Adult↗
PubMed1982

Situational variations of blood pressure in ambulatory hypertensive patients.

Blood pressure and heart rate were recorded at 15-min intervals for 24 hr in 60 untreated patients with uncomplicated mild essential hypertension using a new automatic noninvasive portable recorder. During the recording, the patients went about their normal daily routine, of which they kept a detailed record. The data were analyzed for five different recording situations: in the clinic, at work, at home, asleep, and average of the entire 24-hr period. Twenty-four hour readings were also compared with previously obtained casual readings. Clinic readings were correlated with the average 24-hr values, but for individual patients clinic pressures were relatively poor predictors of 24-hr pressures. Pressures recorded in the clinic were also greater than average 24-hr values. Similar degrees of correlation were found between clinic, home, work, and sleep pressures. Pressures recorded in the clinic were similar to pressures at work but higher than at home or asleep. In contrast, heart rate was similar in all conditions except during sleep, when it was lower. Previously measured casual pressures were also correlated with the clinic readings, with systolic values being similar, but diastolic values higher in the clinic during the 24-hr recording. For patients with clinic diastolic pressures in the range 90-104 mm Hg, 24-hr pressures varied from 75 to 100 mm Hg. We conclude that pressures measured casually in the clinic do not accurately reflect average 24-hr pressures and that ambulatory recording is helpful in the evaluation of mildly hypertensive patients.

Adult↗
PubMed1980

Effects of levamisole on in vitro suppressosr cell function in normal humans and patients with systemic lupus erythematosus.

Levamisole-treated mononuclear cells from normal volunteers or from patients with systemic lupus erythematosus (SLE), when cultured with normal allogeneic lymphocytes, did not significantly influence the ability of the latter cells to proliferate when stimulated with either phytohemagglutinin (PHA) or concanavalin A (Con A). Levamisole, furthermore, did not influence the ability of Con A to induce suppressor cell function from normal mononuclear cells. When mononuclear cells from patients with SLE were treated with therapeutic concentrations of levamisole in the presence of Con A, the drug was unable to restore the ability of the Con A to induce normal suppressor cell function. SLE cells treated with a high concentration of levamisole (60 micrograms/ml) in the presence of Con A did show some suppressor cell activity on normal autologous mononuclear cells activated by Con A, but not by PHA. Although the significance of this latter finding is unclear it appears that levamisole at therapeutic concentrations does not influence in vitro suppressor cell function of normal or SLE mononuclear cells.

Concanavalin A↗