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PubMed1996

Prealbumin in nutrition evaluation.

We compressed 16 test-pattern classes of albumin (ALB), cholesterol (CHOL), and total protein (TPR) in 545 chemistry profiles to 4 classes by converting decision values to a number code to separate malnourished (1 or 2) from nonmalnourished (NM) (0) patients, using as cutoff values for nonmalnourished (0), mild (1), and moderate (2): ALB 35, 27 g/L; TPR 63, 53 g/L; CHOL 3.9, 2.8 mmol/L; and BUN 9.3, 3.6 mmol/L. The BUN was found to have too low an S-value to make a contribution to the compressed classification. The cutoff values for classifying the data were assigned prior to statistical analysis, after examining information in the structured data. The data was obtained by a natural experiment in which the test profiles routinely done by the laboratory were randomly extracted. The analysis identifies the values for the variables used that best classify the data and are not dependent on distributional assumptions. The data were converted to 0, 1, or 2 as outcomes, to create a ternary truth table (each row is nnnn, the n value is 0 to 2). This allows for 3(4) (81) possible patterns, without the inclusion of prealbumin (PAB). The emerging system has much fewer patterns in the information-rich truth table formed (a purposeful, far from random, event). We added PAB, coded, and examined the data for 129 patients. The classes are a compressed truth table of n-coded patients with outcomes of 0, 1, or 2 with protein-energy malnutrition (PEM) increasing from an all-0 to all-2 pattern. Pattern class (F = 154), PAB (F = 35), ALB (F = 56), and CHOL (F = 18) were different across PEM class and predicted PEM class (R2 = 0.7864, F = 119, p < E-5). Kruskal-Wallis analysis of class by ranks was significant for pattern class (1E-18), PAB (6.1E-15), ALB (1E-16), CHOL (9E-10), and TPR (5.3E-13). The medians and standard error (SEM) for PAB, ALB, and CHOL of all four PABCLASSES (NM, mild, moderate, severe) are: PAB = 209, 8.7; 159, 9.3; 137, 10.4; 72, 11.1 mg/L, ALB = 36, 0.7; 30.5, 0.8; 25.0, 0.8; 24.5, 0.8 g/L; CHOL = 4.43, 0.17; 4.04, 0.20; 3.11, 0.21; 2.54, 0.22 mmol/L. PAB and CHOL values show the effect of nutrition support on PAB and CHOL in PEM. Moderately malnourished patients receiving nutrition support have PAB values in the normal range at 137 mg/L and at 159 mg/L when the ALB is at 25 g/L or at 30.5 g/L.

Biomarkers↗
PubMed2001

Hearing preservation in patients with vestibular schwannomas with sudden sensorineural hearing loss.

OBJECTIVE: We evaluated hearing outcomes in patients with sudden hearing loss and vestibular schwannoma who underwent a hearing preservation operation for tumor resection in an effort to determine whether a history of sudden sensorineural hearing loss has an impact on subsequent hearing preservation surgery. METHODS: Retrospective chart review of 45 patients operated between 1990 and 1998. Patients were divided into "Recovery" (n = 22) and "No Recovery" (n = 23) groups based on preoperative hearing recovery. Hearing preservation was assessed using the AAO-HNS hearing classification system. RESULTS: Measurable hearing was preserved in 73% of patients, with 47% having good postoperative hearing (AAO-HNS Classes A-B). There was no significant difference in hearing outcome from patients presenting with progressive hearing loss (45% Classes A-B). There was also no difference in postoperative hearing between the "Recovery" and "No Recovery" groups. CONCLUSIONS: Patients with sudden hearing loss and vestibular schwannoma have the same chance of hearing preservation after tumor removal as those with progressive loss. Preoperative recovery of hearing is not predictive of hearing preservation. Available data support the nerve compression theory as the mechanism of sudden hearing loss in patients with vestibular schwannoma.

Adult↗
PubMedDate not supplied

Techniques for field application of lingual ultrasound imaging.

Techniques are discussed for using ultrasound for lingual imaging in field-related applications. The greatest challenges we have faced distinguishing the field setting from the laboratory setting are the lack of controlled head/transducer movement, and the related issue of tissue compression. Two experiments are reported. First, a pilot study identifies important factors in controlling head/transducer movement in field settings. Second, an Optotrak/ultrasound study reports the range of head movement in an optimal field-like setting within and across varying phonetic contexts, as well as the effect of tongue tissue compression on tongue image data. Results suggest that with a simple arrangement involving a head rest or surface, a fixed transducer, and careful design and presentation of stimuli, reliable lingual ultrasound data can be collected in the field.

Adult↗
PubMed2000

Adjusting dissolution specifications for the variability induced by storage conditions.

The United States Pharmacopeia requires that drug products meet established dissolution specifications throughout their shelf life. Whereas chemical stability for six months at accelerated storage conditions is generally regarded as providing a two-year expiry period, stress conditions are not considered predictive of dissolution stability at controlled room temperature. This paper presents an application of response surface methodology intended to incorporate the variability induced by storage temperature and relative humidity into robust product dissolution specifications. Contour plots, depicting one-sided tolerance limits of percent released, are presented as a function of crushing strength and dissolution time.

Compressive Strength↗
PubMed1999

A single case report of healing through specific martial art therapy: comparison of MRI to clinical resolution in severe cervical stenosis: a case report.

OBJECTIVES: A 76-year-old patient with chronic and severe spinal cord compression secondary to cervical stenosis, a cervical osteophyte, and a herniated intervertebral cervical disk had lasting resolution of symptoms after completing a specific, martial art-based, physical therapy program. We wanted to determine if there were structural changes in the cervical spine that could account for the prompt resolution of symptoms. DESIGN: A 76-year-old female completed 8 weeks of a specific, martial art-based, physical therapy. The pretherapy and posttherapy cervical magnetic resonance images (MRIs) were compared. A follow-up evaluation was done at 1 year. RESULTS: The patient was symptom-free within 8 weeks of the start of therapy. She remained symptom-free at 1 year follow-up evaluation. There were no obvious structural differences in the pretherapy and posttherapy MRI studies. CONCLUSIONS: Resolution of symptoms was directly related to the specific martial art therapy. However, there were no changes in the pretherapy and posttherapy MRI studies, suggesting a significant adaptation to the spinal compression had occurred. These data suggest a viable option to surgery in elderly patients with chronic and severe cervical spinal stenosis.

Aged↗
PubMed1997

Murine nucleus pulposus-derived cells secrete interleukins-1-beta, -6, and -10 and granulocyte-macrophage colony-stimulating factor in cell culture.

STUDY DESIGN: Cultures established from murine disc-derived cells were stimulated by lipopolysaccharide. The cells' capacity to secrete proinflammatory cytokines and interleukin-10 with and without lipopolysaccharide stimulation was determined using enzyme-linked immunosorbent assays. OBJECTIVES: To determine the capacity of disc-derived cells to secrete proinflammatory cytokines, and the effect of lipopolysaccharide stimulation on such secretion. SUMMARY OF BACKGROUND DATA: The pathophysiology of compressive radiculopathy is unclear. Inflammation is a possible explanation. Proinflammatory cytokine secretion was demonstrated in herniated nucleus pulposus. It is unknown whether these cytokines are secreted from disc-derived cells or from infiltrating inflammatory cells in the herniated nucleus pulposus. METHODS: Discs were microsurgically harvested from inbred mice and cut to allow the nucleus pulposus to establish cell culture. A study group was exposed to lipopolysaccharide stimulation. Media were harvested from the study and control groups 24 hours later. Secretion of interleukins-1-, -6, and -10, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-alpha were determined using enzyme-linked immunosorbent assays. RESULTS: Basal secretion of interleukins-6 and -10, but no basal secretion of interleukin-1-, granulocyte-macrophage colony-stimulating factor, or tumor necrosis factor-alpha was detected. Secretion of interleukin-1- rose from zero to 27.69 pg/10(5) cells, and granulocyte-macrophage colony-stimulating factor secretion rose from zero to 9.77 pg/10(5) cells after lipopolysaccharide stimulation. A 75-fold increase in interleukin-6 secretion and a 150-fold increase in interleukin-10 secretion were detected after stimulation with lipopolysaccharide. No tumor necrosis factor-alpha secretion was detectable. All result had high statistical significance (all P < 0.001). CONCLUSIONS: Cultured murine disc-derived cells have the capacity to secrete proinflammatory cytokines and interleukin-10 in the absence of inflammatory cells. This finding supports the hypothesis that disc-derived cells are capable of initiating or amplifying an inflammatory process.

Animals↗
PubMed1999

The effect of hydrostatic pressure on intervertebral disc metabolism.

STUDY DESIGN: By the use of pressure vessels, hydrostatic pressure was applied to intervertebral disc cells cultured in an alginate. OBJECTIVE: To test the hypothesis that hydrostatic pressure directly affects the synthesis of collagen and proteoglycan by the intervertebral disc cells. SUMMARY OF BACKGROUND DATA: The influence of compression (both hydrostatic and mechanical) on chondrocyte metabolism was examined in a number of earlier studies. However, in most of these studies, articular cartilage, not intervertebral disc, was used, and in none of these was hydrostatic pressure applied to intervertebral disc cells cultured in alginate. METHODS: Fresh cells were harvested from the lumbar intervertebral discs of dogs. Before their suspension in an alginate gel system, the cells were plated and expanded until they reached confluence. Then, by use of the alginate gel system, the cells were exposed (for up to 9 days) to specific values of hydrostatic pressure inside two stainless steel pressure vessels. One vessel was kept at 1 MPa and the other at atmospheric pressure. The effects of 1 MPa were compared against atmospheric pressure by measuring the incorporation of [3H]-proline and [35S]-sulfate into collagen and proteoglycans, respectively, for the anulus cells and nucleus cells separately, and by determining whether this incorporation was reflected by changes in the levels of mRNA for aggrecan and Types I and II collagen. RESULTS: Comparisons with atmospheric pressure yielded the following findings: 1) In the incorporation studies, the nucleus and anulus cells exhibited a differential response to a hydrostatic pressure of 1 MPa. Collagen and proteoglycan syntheses were stimulated in the nucleus cells and inhibited in the anulus cells. 2) There was no significant increase in cell proliferation, as measured by DNA content, at 1 MPa for either the anulus or nucleus cells. 3) The mRNA levels of collagen (Col 1A1 and Col 2A1) and aggrecan increased at 1 MPa in both the nucleus and anulus cells. CONCLUSIONS: Hydrostatic pressure directly affects the synthesis of collagen and proteoglycan by the intervertebral disc cells.

Aggrecans↗
PubMed2000

Vertebral artery anomaly with atraumatic dissection causing thromboembolic ischemia: a case report.

STUDY DESIGN: A case report is presented. OBJECTIVES: To illustrate a rare cause of atraumatic vertebral artery dissection resulting from anomalous entry of the vessel at the C3 transverse foramen induced by normal physiologic head and neck motion, and to review vertebral artery anatomy and mechanisms whereby it is vulnerable to pathologic compression. SUMMARY OF BACKGROUND DATA: The vertebral artery usually enters the transverse foramen at C6. Rarely, the artery enters at C5 or C4. Only one prior case with entry at C3 has been reported. That patient experienced recurrent quadriplegia and locked-in syndrome caused by vertebral artery obstruction. A 27-year-old woman with a history of classic migraine experienced neurologic symptoms on three occasions related to physiologic neck and arm movements. Magnetic resonance angiogram was not diagnostic, but standard arteriography demonstrated anomalous vertebral artery entry into the C3 transverse foramen and focal dissection. METHODS: Pertinent literature and the patient's history, physical examination, and radiologic studies were reviewed. RESULTS: Standard cervico-cerebral arteriogram demonstrated focal dissection at C4 and thromboembolic complications in distal vertebral and basilar arteries. Initially, diagnosis by magnetic resonance angiogram was elusive. However, arteriography allowed prompt diagnosis followed by anticoagulation with resolution of neurologic symptoms. CONCLUSIONS: Vertebral artery dissection without trauma is rare, but should be considered when neurologic symptoms accompany physiologic cervical movements. For cases in which vertebrobasilar thromboembolic ischemia is suspected, magnetic resonance angiogram may prove inadequate for demonstrating the causative vascular pathology. Therefore, standard cervico-cerebral arteriography should be performed.

Adult↗
PubMed1997

Content-based indexing of images and video.

By representing image content using probabilistic models of an object's appearance we can obtain semantics-preserving compression of the image data. Such compact representations of an image's salient features allow rapid computer searches of even large image databases. Examples are shown for databases of face images, a video of American sign language (ASL), and a video of facial expressions.

Algorithms↗
PubMed2003

Origins of growth stresses in amorphous semiconductor thin films.

Stress evolution during deposition of amorphous Si and Ge thin films is remarkably similar to that observed for polycrystalline films. Amorphous semiconductors were used as model materials to study the origins of deposition stresses in continuous films, where suppression of both strain relaxation and epitaxial strain inheritance provides considerable simplification. Our data show that bulk compression is established by surface stress, while a subsequent return to tensile stress arises from elastic coalescence processes occurring on the kinetically roughened surface.

Journal Article↗
PubMed2006

Estimating the digestibility of Sahelian roughages from faecal crude protein concentration of cattle and small ruminants.

Studies on diet selection and feed intake of ruminants in extensive grazing systems often require the use of simple approaches to determine the organic matter digestibility (OMD) of the ingested feed. Therefore, we evaluated the validity of the one-factorial exponential regression established by Lukas et al. [Journal of Animal Science 83 (2005) 1332], which estimates OMD from the faecal crude protein (FCP) concentration. The equation was applied to two sets of data obtained with free grazing and pen-fed cattle, sheep and goats ingesting low and high amounts of green and dry vegetation of Sahelian pastures as well as millet leaves and cowpea hay. Data analysis showed that the livestock species did not influence the precision of estimation of OMD from FCP. For the linear regression between measured and estimated OMD (%) across n = 431 individual observations, a regression coefficient of r2 = 0.65 and a residual standard deviation (RSD) of 5.87 were obtained. The precision of estimation was influenced by the data set (p = 0.033), the type of feed (p < 0.001) and the feeding level (p = 0.009), and interactions occurred between type of feed and feeding level (p = 0.021). Adjusting the intercept and the slope of the established exponential function to the present data resulted in a compression of the curve; while r2 remained unchanged, the RSD of the regression between measured and estimated OMD was reduced, when compared with the results obtained from the equation of Lukas et al. (2005). Estimating OMD from treatment means of FCP greatly improved the correlation between measured and estimated OMD for both the established function and the newly fit equation. However, if anti-nutritional dietary factors increase the concentration of faecal nitrogen from feed or endogenous origin, the approach might considerably overestimate diet digestibility.

Animal Feed↗
PubMed1978

Ultrasound velocity in major bovine blood vessel walls.

Data on ultrasound velocity, compressibility. and specific acoustic impedance in bovine aorta, pulmonary artery, vena cava, and myocardium are reported and analyzed based on amounts of structural proteins present in these tissues.

Animals↗
PubMed2002

Evidence for nuclear emissions during acoustic cavitation.

In cavitation experiments with deuterated acetone, tritium decay activity above background levels was detected. In addition, evidence for neutron emission near 2.5 million electron volts was also observed, as would be expected for deuterium-deuterium fusion. Control experiments with normal acetone did not result in tritium activity or neutron emissions. Hydrodynamic shock code simulations supported the observed data and indicated highly compressed, hot (10(6) to 10(7) kelvin) bubble implosion conditions, as required for nuclear fusion reactions.

Journal Article↗
PubMed1997

Four-dimensional imaging of living chondrocytes in cartilage using confocal microscopy: a pragmatic approach.

Regulation of cell volume is a fundamental cellular homeostatic mechanism in the face of osmotic stress. In normal articular cartilage, chondrocytes are exposed to a changing osmotic environment. We present a comprehensive protocol for studying the volume regulatory behavior of chondrocytes within intact cartilage tissue using confocal laser-scanning microscopy. Our data acquisition regime optimizes both signal-to-noise and cell viability during time-lapsed three-dimensional (3-D) (x, y, z, t) imaging. The porcine cartilage is treated as an integrated component of the imaging system, and we demonstrate methods for the direct assessment of tissue-induced axial attenuation and image distortion. Parameterized functions describing these two components of image degradation are used to correct experimental data. The current study also highlights the problems associated with the analysis and visualization of four-dimensional (4-D) images. We have devised two new types of data reconstruction. The first compresses each 3-D time point into a single quantitative view, termed a coordinate view. From these reconstructions we are able to simultaneously view and extract cell measurements. A second type, a 4-D reconstruction, uses color to represent relative changes in cell volume, again while maintaining the morphological and spatial information. Both these approaches of image analysis and visualization have been implemented to study the morphology, spatial distribution, and dynamic volume behavior of chondrocytes after osmotic perturbation. We have mapped chondrocyte shape, arrangement, and absolute volume in situ, which vary significantly from the tissue surface through to the underlying bone. Despite the rigid nature of the extracellular matrix, cartilage cells are osmotically sensitive and respond to stimulation of volume regulatory mechanisms. The combined techniques of confocal laser-scanning microscopy and vital cell labeling have enabled us to study, for the first time, the response of chondrocytes in situ to changes in interstitial osmotic pressure.

Animals↗
PubMed1982

Influence of panting frequency on plethysmographic measurements of thoracic gas volume.

Using an integrated flow pressure-corrected body plethysmograph we obtained total lung capacities (TLC) derived from thoracic gas volumes measured at low, medium, and high panting frequencies in 10 healthy men and in 13 patients with chronic airflow obstruction before and after an aerosol of albuterol. Using a gastric balloon we also assessed gastric-to-mouth pressure ratios (delta Pga/delta Pm). In patients before albuterol, estimated TLC remained unchanged from low to medium and increased (not significantly) from medium to high frequency. Healthy subjects and patients after albuterol showed a significant decrease in TLC from low to medium panting frequencies, which persisted after correcting the data for abdominal gas compression using observed delta Pga/delta Pm. In patients after albuterol the results may be explained, at least in part, by intrathoracic airway compliance and mechanical inhomogeneity of the lung. In healthy subjects a remote possibility is the association of mechanical inhomogeneity and nonuniform pleural pressure.

Adult↗
PubMed1984

Left ventricular diastolic pressure-segment length relations and end-diastolic distensibility in dogs with coronary stenoses. An angina physiology model.

Isovolumic relaxation abnormalities have been noted in the ischemic left ventricle, but altered end-diastolic distensibility, as well as the role of right ventricular distention, is debated. Accordingly, left ventricular end-diastolic pressure and myocardial segment length were studied in the open-chest dogs with critical (90% diameter reduction) stenoses on both left anterior descending and circumflex coronary arteries. Regional segment length was measured with ultrasonic crystals placed subendocardially, and ischemia was induced by pacing tachycardia for 3 minutes. Transient vena caval occlusion was done to unload the right ventricle and to produce a series of left ventricular end-diastolic pressure and left ventricular end-diastolic segment length points before and after pacing tachycardia. After pacing tachycardia, left ventricular end-diastolic pressure (9.3 +/- 0.9 to 16.9 +/- 1.5 mm Hg, P less than 0.001) and time constant T of left ventricular isovolumic pressure decline (46 +/- 3 to 60 +/- 5 msec, P less than 0.01) increased, with an increase in left ventricular end-systolic segment length (9.8 +/- 0.3 to 10.5 +/- 0.3 mm, P less than 0.001), and a decrease in fractional shortening (17.6 +/- 1.7 to 14.5 +/- 1.3%, P less than 0.01) in the ischemic region, although right ventricular end-diastolic pressure was unchanged. With vena caval occlusion, right ventricular diastolic pressure fell promptly to near zero, followed by decrease in left ventricular pressure and segment length. In each dog, the left ventricular end-diastolic pressure-end-diastolic segment length relation shifted upward after pacing tachycardia. Pacing tachycardia was performed again in six dogs without stenoses. In this group, fractional shortening was preserved after pacing tachycardia (15.7 +/- 2.3 to 15.3 +/- 2.3%, NS), and left ventricular end-diastolic pressure (9.4 +/- 1.8 to 9.8 +/- 1.8 mm Hg, NS) was unchanged. The left ventricular end-diastolic pressure-segment length relation did not shift upward after pacing tachycardia. These data indicate that extrinsic compression of left ventricle by right ventricle is unlikely to be responsible for the upward shift in this model, and the upward shift in end-diastolic left ventricular pressure-segment length relations, as well as dynamic left ventricular diastolic pressure-segment length, supports the concept that persistent myosin-actin interaction throughout diastole plays an important role in the diastolic abnormalities in this angina physiology model.

Angina Pectoris↗
PubMed2002

Mechanical properties and in vitro degradation of bioresorbable knitted stents.

The aim of this study was to characterize the mechanical properties and in vitro degradation of bioresorbable knitted stents. Each stent was knitted using a single self-reinforced fibre made out of either PLLA or 96L/4D PLA or 80L/20G PLGA. The mechanical and physical properties of the fibres and stents were measured before and after gamma sterilization, as well as during in vitro degradation. The mechanical properties of the knitted stents made out of bioresorbable fibres were similar to those of commercially available metallic stents. The knitting geometry (loop height) had a marked effect on the mechanical properties of the stents. The rate of in vitro degradation in mechanical and physical properties for the PLLA and 96L/4D PLA stents was similar and significantly lower than that of the 80L/20G PLGA stents. The 80L/20G PLGA stents lost about 35% of their initial weight at 11 weeks. At this time, they had lost all their compression resistance strength. These data can be used as a guideline in planning further studies in vivo.

Absorbable Implants↗
PubMed1989

Mechanical adaptation of heart rate change for coronary circulation in patients with and without ventricular hypertrophy.

To clarify the mechanical adaptation and interference of coronary vessels, we studied hemodynamics of coronary circulation in control and 4 different pacing rates (80, 100, 120, 150/min) in 5 patients with angina pectoris (AP) and in 5 patients with hypertrophic cardiomyopathy (HCM). Coronary sinus flow (CSF) was measured by a Webster's thermodilution catheter, and we applied ascorbic acid-platinum reaction for the mean transit time measurement in left coronary flow (t0-t2). Coronary vascular bed (CVB) was obtained by multiplying CSF and t0-t2. CSF in AP gradually increased from 104 +/- 21 ml/min at 72/min to 148 +/- 42 ml/min at 120/min, while CSF in HCM changed slightly from 91 +/- 25 ml/min at 64/min to 94 ml/min at 120/min. Average t0-t2 in HCM was 6.0 +/- 1.6 sec in control which was significantly lower than that in AP (7.8 +/- 0.7 sec). Calculated CVB in AP increased at any given heart rate up to 120/min (13.5 +/- 2.4, 15.8 +/- 1.7, 15.0 +/- 4.7, 15.1 +/- 4.3 ml), but CVB in HCM decreased from 9.1 +/- 2.3 ml at 64/min to 8.1 +/- 1.7 ml at 120/min. These data suggest that myocardial compression and suction at different heart rates and with different cardiac muscle structures play an important role for beat to beat adjustment of coronary circulation in cardiac cycle.

Adaptation, Physiological↗