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Biomedical subjects

D Shapiro

Publications and source records attributed to D Shapiro.

At least 37 records · Page 2Linked to original sources
PubMed1999

Inappropriately low plasma leptin concentration in the cachexia associated with chronic heart failure.

BACKGROUND: Cardiac cachexia is a syndrome of generalised wasting which caries a poor prognosis and is associated with raised plasma concentrations of tumour necrosis factor alpha (TNFalpha). TNFalpha increases secretion of leptin, a hormone which decreases food intake and increases energy expenditure. OBJECTIVE: To determine whether an inappropriate increase in plasma leptin concentration contributes to the cachexia of chronic heart failure. DESIGN: Retrospective case-control study. SETTING: Tertiary referral cardiology unit. PATIENTS: 110 human subjects comprising 29 cachectic chronic heart failure patients, 22 non-cachectic chronic heart failure patients, 33 patients with ischaemic heart disease but normal ventricular function, and 26 healthy controls. INTERVENTIONS: Measurement of: body fat content by skinfold thickness (cachectic males < 27%, females < 29%); plasma leptin, TNFalpha, and noradrenaline (norepinephrine); central haemodynamics in chronic heart failure patients at right heart catheterisation. MAIN OUTCOME MEASURES: Plasma leptin concentration corrected for body fat content, plasma TNFalpha and noradrenaline concentration, and central haemodynamics. RESULTS: Mean (SEM) plasma leptin concentrations were: 6.2 (0.6) ng/ml (cachectic heart failure), 16.9 (3.6) ng/ml (non-cachectic heart failure), 16.8 (3.0) ng/ml (ischaemic heart disease), and 18.3 (3.5) ng/ml (control) (p < 0.001 for cachectic heart failure v all other groups). Plasma leptin concentration remained significantly lower in the cachectic heart failure group even after correcting for body fat content and in spite of significantly increased TNFalpha concentrations. Thus plasma leptin was inappropriately low in cachectic chronic heart failure in the face of a recognised stimulus to its secretion. There was no significant correlation between plasma leptin, New York Heart Association class, ejection fraction, or any haemodynamic indices. CONCLUSIONS: Leptin does not contribute to the cachexia of chronic heart failure. One or more leptin suppressing mechanisms may operate in this syndrome-for example, the sympathetic nervous system.

Adipose Tissue↗
PubMed1999

Age of onset of dental anxiety.

Little attention has been given to the issue of the age of onset of dental anxiety, even though it may have a bearing on the origins of this type of fear. This study aimed to identify the age of onset of dental anxiety and to identify differences by age of onset with respect to potential etiological factors, such as negative dental experiences, family history of dental anxiety, and general psychological states. Data were collected by means of two mail surveys of a random sample of the adult population. Of 1420 subjects returning questionnaires, 16.4% were dentally anxious. Half, 50.9%, reported onset in childhood, 22.0% in adolescence, and 27.1% in adulthood. Logistic regression analyses indicated that negative dental experiences were predictive of dental fear regardless of age of onset. A family history of dental anxiety was predictive of child onset only. Adolescent-onset subjects were characterized by trait anxiety and adult-onset subjects by multiple severe fears and symptoms indicative of psychiatric problems. The three groups were similar in terms of their physiological, cognitive, and behavioral responses to dental treatment. However, adolescent- and adult-onset subjects were more hostile toward and less trusting of dentists. These results indicate that child-onset subjects were more likely to fall into the exogenous etiological category suggested by Weiner and Sheehan (1990), while adult-onset subjects were more likely to fall into the endogenous category.

Adolescent↗
PubMed1999

The international database of self-recorded blood pressures in normotensive and untreated hypertensive subjects.

OBJECTIVES: To pool data from individual subjects in an attempt to determine an operational threshold for making clinical decisions based on the self-recorded blood pressure (SRBP) and to examine how many hypertensive subjects, diagnosed by conventional blood pressure (CBP) measurement, would have a self-recorded blood pressure within the normotensive range if the proposed thresholds were applied. DATA SOURCES: Thirteen research groups studied 4668 untreated subjects. RESULTS: In total 2401 subjects were normotensive, 494 were borderline hypertensive and 1773 were definitely hypertensive. Hypertension had been diagnosed from the mean of 1-6 (median 3) CBP measurements obtained during 1-3 (median 1) visits. The reference values for SRBP measurements determined from the 95th percentiles of the distributions for normotensive subjects were 137 mmHg systolic and 85 mmHg diastolic. Of the subjects with systolic hypertension, 16% had systolic SRBP </= 137 mmHg. Similarly, 25% of those with diastolic hypertension had diastolic SRBP </= 85 mmHg. The probability that hypertensive subjects had SRBP below these thresholds was 34% (diastolic) to 62% (systolic) greater for women than it was for men, was 2-3 times greater if fewer than three CBP measurements had been averaged for establishing the diagnosis of hypertension, and increased by 50% (diastolic) to 126% (systolic) when SRBP had been measured on more than 3 days. In contrast, for each 10 mmHg increment in systolic CBP, this probability decreased by 35% for systolic SRBP and by 11% for diastolic SRBP; for each 5 mmHg increment in diastolic CBP it decreased by 36% for diastolic SRBP. In addition, for systolic blood pressure, the probability decreased by 31% for each 10-year increment in age. CONCLUSIONS: Until the relationship between SRBP and the incidence of cardiovascular morbidity and mortality has been clarified further by prospective studies, a mean self-recorded blood pressure above 137 mmHg systolic or 85 mmHg diastolic may be considered hypertensive. Among the hypertensive patients 16-31% had SRBP below these thresholds, but this proportion decreased if the hypertensive subjects had higher CBP.

Adolescent↗
PubMed1999

The incidence of T2-weighted MR imaging signal abnormalities in the brain of cocaine-dependent patients is age-related and region-specific.

BACKGROUND AND PURPOSE: Cocaine and its metabolites can produce vasospasm, and cocaine-dependent patients are at increased risk for stroke. Based on previous case reports, we hypothesized that the incidence of hyperintense brain lesions observed on T2-weighted MR images would also be increased in asymptomatic cocaine-dependent individuals. METHODS: Sixty-two male "crack" (smoked) cocaine-dependent participants ranging in age from 25 to 66 years were compared with 116 normal male control participants ranging in age from 25 to 80 years. Those with histories of neurologic symptoms or illnesses were excluded. The severity of hyperintense lesions was rated on a 0- to 3-point scale, and ratings of 3 were used in the data analysis as an indicator of a probable pathologic process. Three regions were separately rated: the cerebral white matter, insular subcortex white matter, and subcortical gray matter (basal ganglia and thalamus region). RESULTS: Significantly increased risk of severe lesions was observed in the two white matter regions of the cocaine-dependent group (odds ratio of 16.7 and 20.3) but not in the subcortial gray matter region (odds ratio of 1.4). In the insula subcortex white matter, the risk of lesions increased with age in the cocaine-dependant sample, but remained essentially absent among normal controls through the age of 80 years. In the cerebral white matter, the relationship of age and risk of lesion among normal participants was similar in shape to that in cocaine-dependent participants, but equivalent risk was seen 20 years earlier among cocaine-dependent participants. CONCLUSIONS: Cocaine-dependent participants had a significantly increased age-related risk of white matter damage. The possible clinical implications of this damage are discussed.

Adult↗
PubMed1998

Blood pressure morning surge and hostility.

This study examined the effects of hostility on blood pressure (BP) during the early morning hours before awakening and several hours afterward. Our objective was to determine whether the pattern of BP change and the slope of the morning BP surge were related to hostility. The subjects were 32 patients with a history of Stage 1 hypertension. The morning surge in BP was derived from ambulatory BP monitoring of sleeping and waking hours, which were averaged per subject and centered around the wake-up hour. The periods used were 3 h before and 3 h after awakening. Only systolic blood pressure (SBP) is being reported on in this paper as this is the primary measure found relevant to the morning surge phenomenon. Hostility was assessed by the Buss-Durkee Hostility Inventory (total score). The results revealed significant differences between low and high hostility subjects for overall levels of sleep SBP: 120 +/- 11.4 mm Hg for low hostility and 131.3 +/- 14.9 mm Hg for high hostility subjects (P = .02). Low hostility subjects showed a steep rise in SBP from sleeping to waking while high hostility subjects had almost reached their post-sleep level of SBP in the hours immediately before waking up (P = .03). These data indicate that individual differences in hostility are related to different patterns of BP during sleep and the early morning hours, a period of the day that has been associated with an increased risk of cardiovascular incidents. The data also suggest the need for further study of the significance of hostility and other personality traits and the relationship of these traits to the mechanisms of the morning surge and the risk of cardiovascular events.

Adult↗
PubMed1998

Wrist actigraph measures of physical activity level and ambulatory blood pressure in healthy elderly persons.

A sensitive electronic monitor (Mini-Motionlogger, Ambulatory Monitoring Inc.) attached to the wrist was used to record movements during two 24-hr days of ambulatory blood pressure (BP) and heart rate (HR) recording in 65 women and 54 men between the ages of 55 and 79 years, all of whom were in good health. The objective was to examine the relationship between various measures of physical activity and ambulatory BP and HR during waking and sleeping periods and during various diary-defined behaviors. For waking and sleeping periods, neither the mean nor the variability of the activity measure was associated with the mean or variability of the ambulatory BP and HR measures in between-subjects correlational analyses. Within-subject analyses showed little evidence of significant covariation between activity and BP or HR during either waking or sleeping conditions with most participants showing a slightly positive association. The activity measure discriminated between behaviors associated with little effort (watching television) versus more energetic behaviors (walking). Activity accounted for a relatively small amount of the difference in BP or HR related to overall state (wake, sleep), posture (stand, sit), and social condition (being with family vs. being with friends). The utility of electronic activity monitoring for studies of BP and HR in natural settings is discussed.

Aged↗
PubMed1998

Pain inhibition, nicotine, and gender.

The ability of nicotine to decrease sensitivity to pain in humans has been a subject of dispute. Decreased sensitivity has been demonstrated in studies involving men, whereas the effect has been less obvious or absent in studies involving predominantly, or entirely, women. To determine whether there are gender differences in nicotine's hypoalgesic actions, ratings of electrocutaneous stimulation were obtained from 30 male and 44 female smokers and nonsmokers under placebo and nicotine conditions. Nicotine increased the pain threshold and tolerance ratings of men but had no effect on the pain ratings of women. Among men, there was no effect of smoking history, suggesting that the changes in pain perception reflect a direct pain-inhibitory effect of nicotine rather than a relief from acute nicotine withdrawal. Nicotine had no effect on mood or task ratings, indicating that the antinociceptive effects observed were not due to nicotine's putative mood effects.

Administration, Cutaneous↗
PubMed1998

Effects of age and gender on ambulatory blood pressure and heart rate.

In a large group of young (n = 194) and elderly (n = 148) healthy subjects, we explored the relationship between ambulatory blood pressure (BP) levels, within-subject BP variability, and age in men and women. The questions asked were: Do elderly subjects display higher BP levels and variability compared to a young group? Are there gender differences in BP level and variability? Are these gender differences similar in the young and the elderly subjects? Do age or gender influence BP in a similar way during waking and during sleep? Subjects wore an ambulatory BP monitor (Accutracker II) for 24 h. Individual levels and variability (standard deviations) were calculated for periods when subjects were awake and during sleep. Systolic BP was higher in the elderly women than in the young group. In comparison to the young subjects, both elderly men and women had higher diastolic BP. BP variability while subjects were awake was higher in the elderly, in women in particular. The higher levels of BP variability found in the elderly women may indicate relatively higher risk for end-organ damage, such as silent cerebrovascular damage.

Adolescent↗
PubMed1998

Relationship between blood pressure and subcortical lesions in healthy elderly people.

BACKGROUND AND PURPOSE: The relationship between blood pressure (BP) and heart rate (HR) and MRI assessments of subcortical T2 hyperintensities was evaluated in healthy elderly men and women. METHODS: Casual and 24-hour ambulatory BPs and HR measurements were taken of 144 elderly individuals, aged 55 to 79 years. Subjects had no evidence of previous health disorders. MRI scans of white matter, subcortical gray matter, and insular subcortex were coded for severity of hyperintensities. RESULTS: Mean casual BP for the group was 120/72 mm Hg. With age and sex accounted for, individuals with the highest severity rating of white matter hyperintensities had higher casual, awake, and sleep systolic BPs; higher awake diastolic BPs; greater awake systolic BP variability; and a smaller nocturnal fall in systolic and diastolic BPs than individuals with less severe ratings. Higher severity ratings for subcortical gray matter hyperintensities were associated with elevations in casual, awake, and asleep systolic BPs and a smaller HR drop during sleep. Subjects with higher ratings for the insular subcortex had higher systolic and diastolic BPs (casual, awake, and asleep), greater HR variability during sleep, and a smaller nocturnal fall in HR. CONCLUSIONS: Casual and 24-hour ambulatory BPs and some ambulatory HR measures are associated with subcortical lesions of the brain. Longitudinal studies are needed to further explore the relationship between white matter lesions and cardiovascular measures, as well as the significance of these lesions for cerebrovascular disease in healthy elderly subjects.

Aged↗
PubMed1998

Factors in human serum interfere with the measurement of advanced glycation endproducts.

Advanced glycation endproducts (AGEs) have been implicated in the pathophysiology of coronary heart disease in ageing, diabetes and renal disease. Competitive enzyme-linked immunosorbent assays (ELISAs) have been developed to measure these compounds in serum, but as recognition of AGEs is both carrier protein- and antibody-dependent standardisation is problematic. We report here on another barrier to standardization, as yet unrecognised. During the development of an AGE ELISA, we found that serum samples did not dilute in parallel to AGE standards or each other. This finding was confirmed by recovery studies that showed over-recovery of AGEs at high serum concentrations, but under-recovery at high dilutions of serum in assay buffer. We developed an inhibition assay to detect factors in serum capable of interacting directly with AGEs immobilised on microtitre plates. Binding of these factors prevented recognition of AGEs by a CML monoclonal antibody and a polyclonal anti-AGE antibody, and was neither sugar- nor carrier protein-dependent. We detected the presence of this factor in all human sera tested and also in foetal calf serum. Pre-incubation of sera with AGEs or heat-treatment at 56 degrees C for 30 min. significantly reduced this binding. We are currently investigating the nature of this factor and the possibility that it may be complement. The effect of this factor on immunoassays for AGEs can only be detected by performing parallelism and recovery studies and we suggest the use of the method referred to in this paper to aid interpretation of parallelism data.

Antibodies↗
PubMed1997

Overlap between dental anxiety and blood-injury fears: psychological characteristics and response to dental treatment.

The relationship between dental anxiety and blood/body injury (BI) fears was examined in a sample of 1420 adults. Based on their responses to two mail questionnaires, they were classified into one of four groups: Group 1--neither dentally anxious nor BI fearful; Group 2--BI fearful only; Group 3--dentally anxious only; Group 4--both dentally anxious and BI fearful. Overall, only 16% of dentally anxious subjects were BI fearful while 31.6% of those with high levels of BI fears were dentally anxious. While subjects in Group 2 were more fearful of dentistry than those in Group 1, they were substantially less so than subjects in Groups 3 and 4. Moreover, even BI stimuli in the dental setting evoked lower levels of anxiety for subjects in Group 2 compared to Group 3 and 4. However, rates of fainting or near fainting experiences in the dental situation were similar for all three groups. Group 3 and 4 were similar in terms of fear evoking stimuli and patterns of anxiety response. Subjects in Group 4 had more agoraphobic symptoms and social interaction fears and had higher scores on the Anxiety Sensitivity Index and Speilberger Trait Anxiety Index. This suggests that Group 4 is comprised of individuals who are more likely to be multiphobic and exhibit generalized anxiety states. Although BI fears are a significant component of dental anxiety, their overall contribution is relatively small.

Adult↗