Terahertz diffractive structures for compact in-reflection inspection setup.

Two diffractive optical elements are used to create a compact raster THz scanning setup in reflective configuration. The first one focuses the radiation into the small focal spot on the sample, while the second one collects reflected radiation and focuses it on the detector. To assure small size of the setup and large apertures of optical elements, structures work in the off-axis geometry. Thus, the focal spot is formed 100 mm after and 60 mm below the optical axis of the element, which measures 75 mm in diameter. The designed iterative algorithm allows further minimization of these values.

[The Current Diagnostic Possibilities and Cooperation of Oftalmologist and Neurologist Concerning in Patients with Idiopatic Intracranial Hypertension]. / Soucasné moznosti oftalmologické diagnostiky a spolupráce oftalmologa s neurologem u pacientu s idiopatickou intrakraniální hypertenzí.

PURPOSE: The aim of this paper is to present the current possibilities in idiopatic intracranial hypertension (IIH) diagnostics. Optical coherence tomography belongs to these possibilities in last few years. The necesarry interdisciplinary co-operation of ophthalmologist and neurologist concerning in IIH patients is pointed out in the mentioned case reports. MATERIAL AND METHODS: The issue of diagnostics and care of IIH patients is presented in two case reports. RESULTS: After ophthalmological and neurological examination the diagnosis of idiopathic intracranial hypertension was assessed and the treatment with acetazolamide was started. The patients have been observed in The department of ophthalmology University hospital in Pilsen during the run of the disease by the neoroophthalmologist. The edema of optic nerve has been monitored by fundoscopy and optical coherence tomography. Initially highly distended retinal nerve fiber layer thickness has been decreased with the normalizing of optic nerve head appearence. The patient´s difficulties have gone off during couple of month and the edema of optic nerve papilla has disappeared. According to the education and the regime acquisition our two patients reduced their body weight, so that they influenced favourably the development of their disorder. CONCLUSION: IIH is consequential disorder causing patient´s crucial restriction in an ordinary lifestyle. It could cause difficult changes in vision. The early diagnosis and proper leading of the therapy is fundamental for the next development of patient´s health. KEY WORDS: idiopatic intracranial hypertension, optical coherence tomography, edema of optic nerve head, papilloedema.

Carotid body size on CTA: correlation with comorbidities.

AIM: To test the hypothesis that computed tomographic angiography (CTA) can identify carotid body enlargement in patients with sympathetically mediated diseases. MATERIALS AND METHODS: A retrospective chart review of all patients obtaining CTAs of the cervical vasculature at University of Utah Health Sciences Center over a 6-month period was performed. Widest axial measurements of both carotid bodies were performed on a picture archiving and communication system (PACS). Statistical analysis was then performed to compare the mean carotid body size between control patients and patients with diabetes mellitus, hypertension, and congestive heart failure. RESULTS: Measurements were performed on 288 patients, with 134 controls. Of the remaining 154, 72 patients had diabetes mellitus, 46 had congestive heart failure, and 130 had hypertension. The control patients had a mean carotid body diameter of 2.3 mm. There was a statistically significant (p < 0.01) 20-25% increase in mean diameter with diabetes mellitus (2.8 mm), hypertension (2.7 mm), and congestive heart failure (2.7 mm; p < 0.01). CONCLUSIONS: This study found a 20-25% larger mean carotid body size in patients with diabetes mellitus, hypertension, and congestive heart failure relative to controls. However, this small enlargement should not mimic other carotid body diseases, such as a paraganglionoma. Moreover, these findings further support the proposed functional relationship between the carotid body and sympathetically mediated disease states.

Breast phantom for comparison X-ray and polarimetric optical tomography imaging.

Breast phantom made as combination of paraffin and INTRALIPID™ was tested by use of X-ray classical computed tomography and polarimetric optical tomography. The INTRALIPID™ is a liquid commonly used for simulation breast tissues optical properties but it is useless as X-ray phantom. During our tests we have observed that X-ray tomography allows to recognize a proper placement of INTRALIPID™ inclusions inside paraffin medium but we cannot distinguish density of INTRALIPID™ within each inclusions. On the other hand the polarimetric optical tomography allows to distinguish density of INTRALIPID™ (0%, 10%, 20%) in inclusions but with relatively low accuracy of their placement.

Malaligned financial incentives of providers in the treatment of chronic diseases: the case of chronic heart failure.

Fee for activity based payment systems create a matrix of conflicting incentives. Hospitals, desiring to maximize revenues and minimize expenses, seek high patient volume with minimal direct variable expenses. The mix of patients, sought bias towards those whose disease related group (DRG), provide the largest contribution to hospitals fixed costs, are frequently characterized by the DRG with high reimbursements, coupled with both low length of stay and low utilization of expensive resources. Physicians, on the other hand, find hospital environments to be extraordinary practice sites. In the hospital, they can generate practice revenue without paying overhead for hospital resources. The incentives to rapidly discharge patients and reduce utilization of resources which are charged to the hospital's expense line are obscure. Hospital treatment of CHF frequently characterizes this conflict; hospitals are seeking rapid through put of CHF patients who neither require expensive hospital based resources nor demonstrate excessive length of stay. Physicians are not encumbered with immediate concerns about costs during the hospitalization, nor the length of hospitalization. The absence of absolute medical consensus on appropriateness of diagnostic and treatment strategies in this population has allowed significant variation on practice patterns to evolve, and consequently, variation on the contribution to hospital fiscal viability made by each physician. (c)1999 by CHF, Inc.

Breath pentane and plasma lipid peroxides in ischemic heart disease.

This study examined the relationship between breath pentane and plasma lipid peroxide levels sampled simultaneously in patients with stable angina (n = 17), unstable angina (n = 23), and controls (n = 10). Plasma lipid peroxides were measured in venous blood as the adduct formed between thiobarbituric acid and malondialdehyde (MDA) using high performance liquid chromatography. Pentane was measured in end-expiratory air using gas chromatography. MDA concentrations in stable (1.81 +/- 0.84 mumol/l) and unstable (1.5 +/- 1.23 mumol/l) angina were not different. However, both groups had significantly (p < 0.005) elevated MDA levels compared to controls (0.41 +/- 0.26 mumol/l). Breath pentane was 0.20 +/- 0.12 nmol/l in controls and not different from stable angina (0.26 +/- 0.20 nmol/l) or unstable angina (0.15 +/- 0.07 nmol/l). When the data from all three groups were combined, there was no correlation between pentane and MDA (rho = -0.09, p = 0.54). In five of the unstable angina patients treated with balloon angioplasty, MDA in pulmonary arterial blood rose by 69 +/- 15% (p < 0.01), and breath pentane rose by 73 +/- 20% (p < 0.01) immediately after balloon deflation. One minute after balloon deflation MDA and pentane had returned to preinflation levels. The results suggest that basal levels of pentane are less useful than MDA as an index of lipid peroxidation in patients with coronary artery disease. However, breath pentane appears to be a sensitive index of reperfusion-induced lipid peroxidation.

Expired hydrocarbons in patients with acute myocardial infarction.

Pentane and isoprene concentrations were analyzed in single end-expiratory breath samples using gas chromatography. Breath analysis was performed in 15 patients with acute myocardial infarction, 15 patients with stable angina, and 15 healthy control subjects. The two patient groups were well matched for age, sex, smoking habits, hypertension and serum cholesterol levels. There was no significant difference in breath pentane concentration in the acute myocardial infarction group (0.29 +/- 0.03 nmol/l) (mean +/- SEM) compared to the group with stable angina (0.31 +/- 0.03 nmol/l) or the control group (0.36 +/- 0.04 nmol/l). However, breath isoprene concentration was higher (p < 0.01) in the acute myocardial infarction group (11.4 +/- 1.2 nmol/l), compared to both the stable angina group (7.7 +/- 0.5 nmol/l) and the control group (7.1 +/- 1.0 nmol/l). There was no difference in either the pentane or isoprene concentrations between the control group and the group with stable angina. Since pentane is thought to be an index of lipid peroxidation, the results do not support the presence of enhanced lipid peroxidation in acute myocardial infarction in the absence of thrombolytic therapy or primary angioplasty. The mechanism responsible for isoprene elevation in acute myocardial infarction is unknown.

Effect of acute edema on left ventricular function and coronary vascular resistance in the isolated rat heart.

The impact of acute myocardial edema on coronary flow and left ventricular performance was studied in isolated isovolumic rat hearts. After 15 min of aortic perfusion with Krebs-Henseleit buffer, hearts (10/group) were either removed for determination of water content or perfused for another 90 min. Three groups were perfused at a constant pressure of 60, 100, or 140 mmHg, and two groups were perfused at 60 or 140 mmHg with adenosine added. Compared with the 15-min group, there was a significant increase in water content in all groups except the 60-mmHg group (P < 0.005). There was a direct linear relationship between increases in coronary vascular resistance over time and water content (P < 0.0001). A decrease in developed pressure and peak +dP/dt was observed only in those groups that accumulated water. An inverse linear relationship was found between changes in developed pressure and water content (P = 0.0001). Water content had no effect on end-diastolic pressure below 5 ml/g; above 5 ml/g, a direct linear relationship was evident (P = 0.009). The results suggest that myocardial edema increases vascular resistance and decreases systolic performance. End-diastolic pressure is less influenced by edema than either systolic or coronary vascular function.

Pentane and isoprene in expired air from humans: gas-chromatographic analysis of single breath.

Both pentane and isoprene are excreted in human breath. Although pentane is considered an index of lipid peroxidation, the significance of isoprene is unknown. Having a similar boiling point, these two hydrocarbons are difficult to separate by gas chromatography. We separated pentane from isoprene on both a Poraplot Q and a Poraplot U column, injecting single-breath samples directly into a gas chromatograph. The breath samples were pressurized to 800 mmHg to increase the amount of sample volume delivered to the column. In a group of 43 healthy volunteers, the concentrations of end-expiratory pentane and isoprene were 0.57 +/- 0.3 and 7.05 +/- 3.53 nmol/L, respectively. There was a significant linear correlation (r = 0.57, P < 0.0001) between age and pentane concentration in expired air; isoprene showed no correlation with age or pentane concentrations. The age-related increase in pentane production suggests that oxidative stress may play a role in the aging process in humans. The method described should allow for rapid, inexpensive, serial measurement of expired pentane and isoprene.

[Relations between acute myocardial edema, coronary vascular resistance and left ventricular mechanics in isolated rat heart]. / Relazione tra edema miocardico acuto, resistenze vascolari coronariche e meccanica ventricolare sinistra nel cuore di ratto isolato.

To evaluate the effect of acute myocardial edema (ME) on coronary vascular resistance (CVR) and left ventricular (LV) mechanical function, the LV water content (% of total weight) of seven groups (n = 10 each) of isolated rat heart was determined. Group I included non-perfused hearts and served as control. Group II was perfused with Krebs-Henseleit buffer only for the brief equilibration period which preceded every experiment. Group III, IV and V were perfused for 90 min at the constant pressure of 60, 100 and 140 mmHg respectively. Group VI and VII were perfused for 90 min at the constant flow of 10 and 30 ml/min respectively. The hearts were contracting isovolumically against a fluid-filled latex balloon with fixed volume. CVR and LV functional parameters were measured throughout the whole perfusion period. The water content of Group I (78.2 +/- 0.3%) was significantly lower than Group II (80.5 +/- 0.3%). A higher degree of ME was present in groups III, IV and V (80.2 +/- 0.3, 81.4 +/- 0.3 and 83.3 +/- 0.2%, respectively), as well as in groups VI and VII (80.7 +/- 0.1 and 83.4 +/- 0.2%, respectively). CVR significantly increased over time in groups III, IV and V (about +30, +35 and +50%, respectively), as well as in groups VI and VII (about +22 and +20%, respectively). LV developed pressure did not change over time in Group III (which did not show further fluid accumulation after the equilibration period); it decreased on the other hand in groups IV (about -27%) and V (about -40%). In groups VI and VII, LV developed pressure showed as increase (about +28%) and a reduction (about -29%) respectively. In conclusion, in the isolated crystalloid-perfused rat heart, ME is directly dependent on coronary perfusion pressure and/or flow. ME induces an increase in CVR and a rapid and significant depression of LV function.

Breath pentane is a marker of acute cardiac allograft rejection.

Breath pentane, a product of lipid peroxidation that serves as a noninvasive marker of tissue inflammation and injury, was measured as a potential marker of acute cardiac allograft rejection. We prospectively studied 37 consecutive outpatients with stable cardiac allograft function. Breath pentane levels were measured with gas chromatography, and the results were compared the findings from routine surveillance endomyocardial biopsy. Data analysis was performed with the receiver operating characteristic curve and negative and positive predictive values. Statistical methods include analysis of variance and two-sample t-tests. Histopathologic findings consistent with rejection were present on endomyocardial biopsy in 52% of the subjects. Pentane levels in healthy control subjects did not differ from those of patients undergoing transplantation without rejection. Average pentane excretion for subjects with mild rejection (4.2 +/- 2.8 nmol/L) or moderate rejection (5.4 +/- 2.6 nmol/L) exceeded that seen in subjects who did not have rejection (1.7 +/- 0.9 nmol/L) (p < 0.02). A pentane cutoff value of 2.43 nmol/L, chosen to give the highest negative predictive value, had a sensitivity of 0.80. We concluded that breath pentane excretion is a sensitive noninvasive screening test for the detection of cardiac allograft rejection.

Abnormal ambulatory left ventricular ejection fraction in heart transplant arteriopathy.

The morbidity and mortality from heart transplantation has been reduced dramatically over the last several years. However, the long-term survival in heart transplant recipients is limited by arteriopathy in the allograft coronary arteries, the pathophysiology of which is poorly understood. The diagnosis of this arteriopathy is at present limited to cardiac catheterization. Noninvasive studies have proven to be of limited benefit in diagnosing this arteriopathy. The authors performed cardiac vest studies in nine heart transplant recipient patients. Six of the vest studies were abnormal; five of the patients had documented transplant coronary artery disease by cardiac catheterization. They found that the sensitivity and negative predictive value of the cardiac vest in identifying arteriopathy in transplant recipients was 100%. The authors propose that cardiac vest could be a sensitive, noninvasive screening test for identifying arteriopathy in heart transplant recipients.

Implications of an audible third heart sound in evaluating cardiac function.

We prospectively compared auscultatory findings of third heart sounds with radionuclide ventriculographic analysis of systolic and diastolic function. Cardiac auscultation was done to detect an S3 in patients referred for radionuclide ventriculographic analysis of ventricular function. Of 49 adult men with the diagnosis of chronic, nonvalvular heart failure who were referred for the evaluation of heart failure, 22 (45%) at the time of the ventriculography had an S3 present on examination. For the entire study group, the radionuclide ventriculography-derived ejection fraction was 33% +/- 19.5 (mean +/- SD) with a range of 6% to 74%. The peak ejection rate was 2.05 +/- 1.09 end-diastolic volume per second with a range of 0.30 to 4.56. The peak filling rate was 1.97 +/- 1.07 end-diastolic volume per second with a range of 0.44 to 3.94, and the time to peak filling rate was 0.18 +/- 0.11 per second with a range of 0.05 to 0.61. The presence of an S3 was associated with a reduced ejection fraction and also with impaired diastolic function as determined by the peak filling rate. The sensitivity and specificity for the S3 in detecting abnormal systolic function (ejection fraction < 50%) were 51% and 90%, respectively, with a positive predictive value of 95% and a negative predictive value of only 32%. For an ejection fraction of less than 30%, the S3 had a sensitivity and specificity of 78% and 88%. The presence of an S3 was highly predictive of an abnormal ejection fraction. The absence of an S3, however, is not uncommon in patients with a mildly impaired ejection fraction.

Elevated breath pentane in heart failure reduced by free radical scavenger.

UNLABELLED: Pentane, a product of lipid peroxidation, has been detected in situations involving ischemic injury. Such injury may be limited if lipid peroxidation can be controlled by antioxidants. The role of lipid peroxidation in chronic heart failure (CHF) was assessed by measuring breath pentane in patients with CHF vs. age matched controls. The effect of a free radical scavenger on pentane released during CHF was also measured. Pentane levels were correlated with the daily dose of captopril, a sulfhydril-containing drug used to treat CHF, which is an angiotensin converting enzyme inhibitor. To separate the scavenging effects of captopril from the pharmacologic effects of converting enzyme inhibitors, a crossover study using a nonsulfhydril inhibitor was used. Patients with CHF excreted (p < 0.005) high concentrations of pentane (5.7 +/- 2.1 vs. control 3.6 +/- 1.2 nmol/l). Patients treated with captopril also had significantly higher (p < 0.05) excretion of pentane than the control patients (4.7 +/- 1.3 vs. 3.6 +/- 1.2 nmol/l). The dose of captopril was inversely proportional to the concentration of pentane excreted (r = 0.55, p < 0.05). Pentane excretion during captopril therapy was significantly lower before (p < 0.01) and after (p < 0.02) nonsulfhydril inhibitor therapy. CONCLUSION: breath pentane is elevated in CHF and it can be reduced by a free radical scavenger. This reduction of pentane excretion is not a converting enzyme inhibitor class effect.

Nutrition in acute pulmonary disease.

Acutely stressed patients with chronic pulmonary disease have a particular need for accurate nutritional assessment and appropriate nutritional therapy. Loss of skeletal muscle, often extensive, can be paralleled by dramatic alterations in cellular function; inadvertent provision of excessive calories or of individual substrates may produce more harm than benefit. In the absence of a single "gold standard" for nutritional assessment and monitoring, no single value should take precedence over the entire clinical picture, which should be thoughtfully assessed and reassessed, with both the patient's nutritional needs and the consequences of their provision kept in mind. In the future, assessments of the impact of nutritional intervention will probably rely more heavily on functional tests of specific organs and of the immune system. Intervention will be based not only on provision of calories, individual substrates, vitamins, and minerals, but also on control of the inflammatory response in order that the nutrients may be properly utilized.

The use of beta-blockade therapy in treatment of congestive heart failure.

If the activation of the sympathetic nervous system in chronic heart failure is causally related to progressive pump dysfunction, sudden death, and exercise intolerance, then selective blockade of the beta-adrenergic system may prove to be therapeutically beneficial. This report briefly reviews the evidence that there is systemic activation of the sympathetic nervous system in chronic heart failure, postulates mechanisms by which this activation might contribute to the morbidity and mortality of the syndrome, and hypothesizes further regarding how beta blockade may be beneficial in heart failure. The clinical evidence that the use of beta blockers is beneficial in the treatment of chronic heart failure is reviewed.