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Biomedical subjects

David Shapiro

Publications and source records attributed to David Shapiro.

At least 19 recordsLinked to original sources
PubMed2006

Baroreflex mechanisms in major depression.

BACKGROUND: Recent studies have shown that depressive disorder is associated with impaired baroreceptor or baroreflex sensitivity, which is proposed to be a predisposing factor for sudden death in patients with manifest cardiac disease. These studies have not evaluated the afferent and efferent components of the cardiac baroreflex loop or other baroreflex mechanisms that regulate target processes (cardiac metabolism and blood pressure variability) related to the impairment. The objective of this study was to gain more insight into autonomic functioning in depressive disorder to more fully examine the potential basis for increased cardiac mortality. METHODS: The subjects were 28 women and men with unipolar major depression who were taking antidepressant medications and who were in partial remission and free of cardiovascular or other serious disease, and 28 healthy control subjects matched for sex, age, and ethnicity. The two samples were compared for negative affective dispositions (anger expression, hostility, defensiveness, anxiety), spontaneous (closed-loop) baroreflex activity, heart rate, heart rate variability, systolic blood pressure, and heart rate-systolic blood pressure double product under resting conditions. RESULTS: Depressed patients showed a general disposition to anger suppression coupled with higher hostility and anxiety, and lower defensiveness. The patients showed higher general sympathetic activity (high levels of blood pressure, low-frequency heart rate variability) and lower parasympathetic-related activity (high heart rate and reduced high frequency heart rate variability) with affected cardiac metabolism estimated by the double product. Depressed patients had lower baroreflex sensitivity related to a higher gain of the afferent component of the baroreflex without respective gain adjustment of its efferent component (reflex gain 'de-afferentation'). It was coupled with a compensatory higher number of effective baroreflex reactions (reflex gating 're-afferentation'). Antidepressant agents and depressed mood had additional independent effects on baroreflex sensitivity through the efferent component of the cardiac baroreflex loop. CONCLUSIONS: The data indicate that different baroreflex components and mechanisms may be impaired in patients with depression and may contribute to their increased cardiac risk.

Adult↗
PubMed2006

Reconstruction of a yeast cell from X-ray diffraction data.

Details are provided of the algorithm used for the reconstruction of yeast cell images in the recent demonstration of diffraction microscopy by Shapiro, Thibault, Beetz, Elser, Howells, Jacobsen, Kirz, Lima, Miao, Nieman & Sayre [Proc. Natl Acad. Sci. USA (2005), 102, 15343-15346]. Two refinements of the iterative constraint-based scheme are developed to address the current experimental realities of this imaging technique, which include missing central data and noise. A constrained power operator is defined whose eigenmodes allow the identification of a small number of degrees of freedom in the reconstruction that are negligibly constrained as a result of the missing data. To achieve reproducibility in the algorithm's output, a special intervention is required for these modes. Weak incompatibility of the constraints caused by noise in both direct and Fourier space leads to residual phase fluctuations. This problem is addressed by supplementing the algorithm with an averaging method. The effect of averaging may be interpreted in terms of an effective modulation transfer function, as used in optics, to quantify the resolution. The reconstruction details are prefaced with simulations of wave propagation through a model yeast cell. These show that the yeast cell is a strong-phase-contrast object for the conditions in the experiment.

Algorithms↗
PubMed2006

Surgical perspectives in peptic ulcer disease and gastritis.

For much of the twentieth century, surgery was frequently the solution for peptic ulcer disease. Our understanding of the pathophysiology of ulcers paralleled the development of potent pharmaceutical therapy. As the surgical world developed parietal cell vagotomy which would minimize the complications of surgery, patients failing medical therapy became rare. Emergent surgery for complicated peptic ulcers has not declined however. The development of proton pump inhibitors and the full understanding of the impact of H pylori has led to a trend towards minimalism in surgical therapy for complicated peptic ulcer disease. In addition to the changes in patient care, these developments have had an impact on the training of surgeons. This article outlines these trends and developments.

Digestive System Surgical Procedures↗
PubMed2006

Ambulatory blood pressure and family history of hypertension in healthy men and women.

BACKGROUND: Family history of hypertension is a primary predictor of high blood pressure (BP). This study attempted to determine whether there is a gradual increase in BP between individuals with two hypertensive parents, one hypertensive parent, and normotensive parents and whether this increase is apparent with both ambulatory and casual BP assessments in men as well as in women. METHODS: A total of 220 healthy men and women, aged 22 to 50 years, completed two 24-h ambulatory BP sessions (one work day and one off work day). Based on family history information obtained from parents, three groups were formed: subjects with two hypertensive parents, one hypertensive parent, and normotensive parents. Work and off work days did not differ; analyses were based on mean values of the 2 days. RESULTS: Men with two hypertensive parents had higher daytime and night-time ambulatory BP than men with normotensive parents. Those with one hypertensive parent had intermediate BP levels. Ambulatory BP was not associated with family history in women. Also, men with one or two hypertensive parents had higher ambulatory BP than women with hypertensive parents, whereas offspring of normotensive parents exhibited no sex differences in BP. CONCLUSIONS: Elevated systolic and diastolic BP throughout the day and night seems to characterize men with two hypertensive parents. In evaluating the relationship between family history of hypertension and BP, it is important to use ambulatory BP measures, differentiate between individuals with one and with two hypertensive parents, and focus on gender differences in BP.

Adult↗
PubMed2006

Hemodynamic profile, compensation deficit, and ambulatory blood pressure.

This study hypothesized that physiologically grounded patterns of hemodynamic profile and compensation deficit would be superior to traditional blood pressure reactivity in the prediction of daily-life blood pressure. Impedance cardiography-derived measures and beat-to-beat blood pressure were monitored continuously in 45 subjects during baseline and four tasks. Ambulatory blood pressure measures were obtained combining data from one work day and one off day. The mediating effects of gender and family history of hypertension were considered. Only gender was significantly associated with hemodynamic profile. Regression analysis indicated that typical reactivity measures failed to predict everyday life blood pressure. After controlling for gender and baseline blood pressure, hemodynamic patterns during specific tasks proved to be strong predictors, overcoming limitations of previous reactivity models in predicting real-life blood pressure.

Adult↗
PubMed2006

High-resolution ab initio three-dimensional x-ray diffraction microscopy.

Coherent x-ray diffraction microscopy is a method of imaging nonperiodic isolated objects at resolutions limited, in principle, by only the wavelength and largest scattering angles recorded. We demonstrate x-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the three-dimensional diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a nonperiodic object. We also construct two-dimensional images of thick objects with greatly increased depth of focus (without loss of transverse spatial resolution). These methods can be used to image biological and materials science samples at high resolution with x-ray undulator radiation and establishes the techniques to be used in atomic-resolution ultrafast imaging at x-ray free-electron laser sources.

Algorithms↗
PubMed2006

Self-reproach and personal responsibility.

A confusion exists between the aims of psychotherapy of diminishing self-reproach, on the one hand, and increasing the experience of personal responsibility, on the other. In order to clarify this problem a distinction is made between moral responsibility, central to self-reproach, and psychological responsibility or agency. Self-reproach is shown to be inimical to the experience of psychological responsibility, with reference to psychotherapy of a case of severe obsessive self-reproach.

Adult↗
PubMed2005

Biological imaging by soft x-ray diffraction microscopy.

We have used the method of x-ray diffraction microscopy to image the complex-valued exit wave of an intact and unstained yeast cell. The images of the freeze-dried cell, obtained by using 750-eV x-rays from different angular orientations, portray several of the cell's major internal components to 30-nm resolution. The good agreement among the independently recovered structures demonstrates the accuracy of the imaging technique. To obtain the best possible reconstructions, we have implemented procedures for handling noisy and incomplete diffraction data, and we propose a method for determining the reconstructed resolution. This work represents a previously uncharacterized application of x-ray diffraction microscopy to a specimen of this complexity and provides confidence in the feasibility of the ultimate goal of imaging biological specimens at 10-nm resolution in three dimensions.

Freeze Drying↗
PubMed2005

Screening healthy infants for iron deficiency using reticulocyte hemoglobin content.

CONTEXT: Current clinical practice relies on hemoglobin to detect iron deficiency, which misses infants not yet anemic and places them at higher risk for neurocognitive impairment. Reticulocyte hemoglobin content (CHr) has never been compared with hemoglobin for screening healthy infants. OBJECTIVES: To evaluate CHr for detecting iron deficiency without anemia in healthy 9- to 12-month-old infants and to compare CHr with hemoglobin in screening for iron deficiency in this population. A secondary objective was to explore the association between CHr and subsequent development of anemia. DESIGN, SETTING, AND PATIENTS: A prospective observational cohort study of 202 healthy 9- to 12-month-old infants from an urban, hospital-based, primary care clinic in Boston, Mass, who were screened for iron deficiency between June 2000 and April 2003, and followed up for a median of 5.6 months. MAIN OUTCOME MEASURES: Iron deficiency (transferrin saturation <10%) and anemia (hemoglobin <11 g/dL). RESULTS: Of 202 infants enrolled, 23 (11.4%) had iron deficiency and 6 (3%) had iron deficiency and anemia. Iron-deficient and non-iron-deficient infants had significantly different values for all measured hematological and biochemical markers for iron deficiency. Optimal CHr cutoff for detecting iron deficiency was 27.5 pg (sensitivity, 83% and specificity, 72%); a hemoglobin level of less than 11 g/dL resulted in a sensitivity of 26% and a specificity of 95%. Reticulocyte hemoglobin content was more accurate overall than hemoglobin was for detecting iron deficiency (area under the receiver operating characteristic curve, 0.85 vs 0.73; P = .007). A CHr of less than 27.5 pg without anemia at initial screening was associated with subsequent anemia when screened again in the second year of life (risk ratio, 9.1; 95% confidence interval, 1.04-78.9; P = .01). CONCLUSIONS: A CHr of less than 27.5 pg is a more accurate hematological indicator of iron deficiency compared with hemoglobin of less than 11 g/dL in these healthy 9- to 12-month-old infants. Further studies are warranted to determine whether CHr should be the preferred screening tool in the early detection of iron deficiency in infants.

Anemia, Iron-Deficiency↗
PubMed2005

Ambulatory blood pressure and the brain: a 5-year follow-up.

OBJECTIVE: To determine if initial values of casual and ambulatory systolic blood pressure (SBP) predict white matter hyperintensities, insular subcortex hyperintensities, and brain atrophy 5 years later in a group of healthy elderly individuals. METHODS: The authors studied 155 healthy men and women, aged 55 to 79 years. Two 24-hour ambulatory blood pressure (BP) sessions assessed BP level and variability during waking and sleep. Hyperintensities and total brain volume were quantified by MRI. Procedures were repeated 5 years later in 78% (121) of subjects. RESULTS: Hyperintensities and brain atrophy increased over time, with greater increases among older subjects. The presence of increased BP level and variability initially and again 5 years later had negative consequences for the brain. Independent of age, the greater the initial SBP, the greater the likelihood that individuals would have severe white matter hyperintensities after 5 years. Also, elevated casual SBP was associated with severe insular subcortex hyperintensities and greater SBP sleep variability with increased brain atrophy. CONCLUSIONS: Among healthy elderly individuals whose initial, average, casual blood pressure (BP) was relatively low (116.9/71.1 mm Hg), small increases in casual and 24-hour ambulatory BP measures were associated with greater brain atrophy and subcortical lesions after 5 years.

Age Factors↗
PubMed2005

Carotid artery angioplasty with stenting and postprocedure hypotension.

INTRODUCTION: Although carotid endarterectomy (CEA) has become established as the preferred approach to the management of critical carotid stenosis, carotid angioplasty with stenting (CAS) has arisen as a competitive modality. We report here a nonindustry-supported experience using CAS in a nonselected patient population suffering from critical carotid stenosis. METHODS: All patients suffering from carotid stenosis (>50% symptomatic or >80% asymptomatic) were offered CAS or CEA. The first 36 patients who underwent attempted CAS over this last year are reported here. CAS was performed with the SMART PRECISE (Cordis, Inc, Miami Lakes, FL) or ACCULINK (Guidant, Inc, St Paul, MN) stents. All procedures were performed with cerebral protection. RESULTS: The planned procedure success rate was 97%, and the major adverse event (MAE) rate was 3.0% in 35 patients who underwent successful CAS. This included a minor stroke and a subendocardial myocardial infarction in the same individual. Both events were attributed to sustained postprocedure hypotension. The most frequent intraprocedure complications observed were bradycardia and hypotension. Persistent postprocedure hypotension requiring vasopressor support complicated 23% of cases. The average duration of vasopressor support in this group was 21 hours. CONCLUSION: CAS can be accomplished with an MAE comparable to CEA and will likely become the dominant alternative to CEA for the management of carotid stenosis. Management of periprocedural cardiovascular instability represents one of the most important elements in the safe conduct of CAS.

Aged↗
PubMed2005

In-house trauma attendings: is there a difference?

INTRODUCTION: Outcomes of patients who met trauma activation criteria were examined before and after implementation of in-house attending call. MATERIALS AND METHODS: Outcomes for the out-of-house period (OH) (February 1, 2001 to October 31, 2002) were compared with the in-house period (IH) (November 1, 2002 to June 30, 2004). Measures included overall mortality, length of stay (LOS) in the hospital, intensive care unit (ICU) and emergency department, and preventable deaths. RESULTS: A total of 2,019 trauma activations were studied (1,036 OH, 983 IH). The groups were equivalent on admission. There was no difference in hospital LOS, ICU LOS, ventilator days, or overall mortality. Preventable deaths occurred in 8.1% of the OH group and in 1.0% of the IH group (P < .02). CONCLUSIONS: Aggregate statistics and the use of surrogate markers to determine outcomes may not accurately portray the impact of attending surgeons on the quality of care. Implementation of in-house call resulted in a decreased incidence of preventable deaths.

Adult↗
PubMed2005

Moods in everyday situations: effects of menstrual cycle, work, and stress hormones.

OBJECTIVE: This study examined women's mood responsiveness on work and off days during different phases of the menstrual cycle. METHODS: Self-reports of negative, positive, and energy dimensions of mood were obtained throughout the day on two work and two off days during the luteal and follicular phases of the menstrual cycle in 203 women nurses. Individual differences in daytime and nighttime epinephrine, norepinephrine, and cortisol were assessed. RESULTS: High daytime norepinephrine, epinephrine, and cortisol levels were associated with higher ratings of stress and tired, and with lower ratings of happy. The phase of the menstrual cycle and the day factor (workday, off day) were also associated with mood differences, and the direction of the effects depended on hormone levels and hormone sampling period. CONCLUSION: The experience of moods is affected by the arousal-related interaction of hormone levels with the phase of the menstrual cycle and occupational stress.

Activities of Daily Living↗
PubMed2004

Relationship between daytime sleepiness and blood pressure in healthy older adults.

BACKGROUND: Some sleep disorders have been linked to hypertension, but few studies have examined the relationship between daytime sleepiness and blood pressure (BP). This study attempted to determine whether scores on a short questionnaire assessing daytime sleepiness (Epworth Sleepiness Scale [ESS]) were associated with BP and could be used to predict hypertension after 5 years in healthy older adults who had not previously been diagnosed with hypertension. METHODS: A group of 157 healthy men and women 55 to 80 years of age completed an extensive medical examination, a series of psychosocial tests, and two 24-h ambulatory BP sessions. After 5 years the procedures were repeated in 133 (85%) of the subjects. Psychosocial variables and BP were compared in subjects scoring high (score of > or = 10) and low (< 10) on the ESS. RESULTS: Compared to individuals with low ESS sores, those scoring high had increased casual and sleep BP as well as higher systolic BP levels and diastolic BP variability during waking hours, and reported higher levels of anger, depression, anxiety, and intensity of psychological symptoms as well as lower defensiveness. Individuals with high ESS scores were more likely to be diagnosed with hypertension 5 years later. Groups with high and low ESS scores did not differ significantly on any other variables. CONCLUSIONS: The ESS, a simple measure of daytime sleepiness, identified individuals at risk for hypertension. Future studies should investigate the possibility that diagnosis and treatment of daytime sleepiness could aid in BP reduction and ultimately in decreased morbidity and mortality from cardiovascular disorders.

Aged↗
PubMed2004

Moods in everyday situations: effects of menstrual cycle, work, and personality.

OBJECTIVE: This study examined women's moods on work and off days during different phases of the menstrual cycle. METHOD: Self-reports of the moods angry, happy, sad, stressed, tired, and anxious were obtained on two work and two off days during the luteal and follicular phases of the menstrual cycle in 203 nurses. Individual differences in anger expression, anxiety, and hostility were assessed. RESULTS: Ratings of anxious, stressed, and tired were higher and happy and sad were lower on the workday than the off day. Menstrual cycle phase was associated with mood differences depending on the day (work, off work) and individual differences in personality traits. CONCLUSIONS: The experience of moods in everyday life is affected by overall levels of stress and phase of the menstrual cycle. The findings suggest the need to refine sociopsychobiological and clinical models of mood regulation and of risk for disease.

Adult↗
PubMed2003

A 5-year follow-up of ambulatory blood pressure in healthy older adults.

BACKGROUND: This study assessed 5-year changes in ambulatory blood pressure (ABP) in healthy, older individuals and determined the extent to which it could be predicted from earlier BP measures and other cardiovascular risk factors. METHODS: A total of 162 men and women, aged 55 to 79 years, with no prior medical disorders, completed a medical examination and two 24-h ABP sessions. The procedures were repeated 5 years later in 80% (130) of these subjects. A modified hierarchical regression analysis was used to determine whether initial ABP and casual blood pressure (CBP) measures and demographic and physical examination data could predict ABP in 5 years. RESULTS: The CBP and most ABP levels during waking and sleep increased after 5 years. However, CBP remained in the normotensive range for 73% of the subjects. The ABP variability tended to decrease over time. The ABP and CBP measures accounted for at least 50% of the variance in the prediction of ABP level after 5 years. In comparison, the predictability of ABP variability was quite low, particularly during sleep (<30% of the variance accounted for). CONCLUSIONS: The ABP and CBP were good predictors of future ABP level in healthy older subjects, but ABP variability was more difficult to predict. Except for age, none of the standard cardiovascular risk factors contributed significantly to the prediction of ABP level or variability.

Aged↗
PubMed2003

Who should be doing laparoscopic bariatric surgery?

BACKGROUND: The training and credentialing of surgeons for laparoscopic bariatric surgery is controversial. We sought to determine if there is an association between surgeons' practice and choice of open or laparoscopic bariatric surgery. METHODS: Members of the ASBS were surveyed via email. Associations were tested with Cochran-Mantel-Haenszel or Pearson's chi-square. RESULTS: 104/472 members responded; 65% were in private practice; 47% did 1-5 operations/week, 48% offered open procedures only, and 76% undertook gastric bypass. Respondents believe that laparoscopic procedures: should mimic open ones (77%), are safe (63%), should be evaluated by clinical trials (48%), and that expertise in bariatric surgery is more important than laparoscopic experience. 75% believe that courses and preceptorships are important. Regarding laparoscopic operations, surgeons doing only open procedures believe that: 1) the ASBS should be the main credentialing body; 2) surgeons should do > 25 open before laparoscopic ones; and 3) clinical trials are needed (P < 0.02, all). Surgeons with laparoscopic training or practices believe that laparoscopic surgery is safe and effective (P < 0.002). Both laparoscopic and open surgeons believe bariatric surgeons should be the only surgeons doing laparoscopic bariatric procedures (P < 0.008). CONCLUSIONS: There is consensus that laparoscopic bariatric surgery should be undertaken only by surgeons with strong interest in bariatric surgery. Laparoscopic bariatric surgeons should incorporate lessons learned from open surgery. Both laparoscopic and open bariatric surgeons should seek added expertise via courses and preceptorships. The skepticism of surgeons with 'open' practices could be addressed by clinical trials. The ASBS should maintain its leadership position and foster emerging technologies.

Clinical Competence↗