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PubMed1975

Statistical correlations of diffuse cerebral atrophy, with special reference to diagnostic and aetiological clues.

To evaluate diagnostic and aetiological clues for diffuse cerebral atrophy, the statistical correlations between 35 pneumoencephalographic and 97 clinical variables in 268 patients were analysed. Each case of diffuce cerebral atrophy was originally of unknown cause, and all had pneumoencephalography. Ventricular diffuse atrophy correlated positively with psychic and co-ordinative impairment and dysarthria, and cortical diffuse cerebral atrophy with psychic impairment (P smaller than 0.01 to 0.001). There was a close correlation (P smaller than 0.001) of cortical diffuse cerebral atrophy with use of vibrating tools at work. Psychic impairment combined with co-ordinative dysfunction and dysarthria is an unspecific syndrome, but should make one think of diffuse cerebral atrophy, Arteriosclerosis, abuse of alcohol, and vibrating tools at work appear to have aetiological significance for some types of diffuse cerebral atrophy. Thus the number of patients with idiopathic diffuse cerebral atrophy may rapidly decline.

Age Factors↗

PubMed2006

Focal MIBI uptake is a better indicator of active myeloma than diffuse uptake.

PURPOSE: Technetium-99m 2-methoxyisobutylisonitrile (MIBI) imaging has been proposed as a front-line investigation to detect bone disease both before and after the treatment of myeloma. In this study, we have compared the pattern of MIBI uptake (focal and diffuse) between patients with proven myeloma and a cohort of patients without myeloma, in order to identify the uptake pattern that best correlates with disease activity. METHODS: Nineteen scans were taken in 16 consecutive patients (nine males and seven females: aged 39-71 yr) with active myeloma. A further 20 scans (10 subjects having MIBI myocardial perfusion scintigraphy and 10 subjects having MIBI parathyroid adenoma localisation studies), comprised the control (non-myeloma) cohort. Scans were evaluated in a double-blinded fashion by two observers for any diffuse skeletal MIBI uptake (homogeneous uptake in spine, sternum and/or long bones), and/or abnormal focal uptake (patchy, focal or tubular uptake in the skeleton or soft tissues). RESULTS: The pattern of MIBI uptake was significantly different in the myeloma-positive subjects and the control cohort. Focal uptake was highly discriminatory, being seen in 15 of 19 (79%) scans of the myeloma-positive group as opposed to one of 20 (5%) scans of the control group (P < 0.0001). In contrast, diffuse uptake was seen in 17 of 19 (89%) scans in patients with myeloma, and in 11 of 20 (55%) of the control cohort (P = 0.02). Using multiple logistic regression analysis, any focal uptake was significantly predictive for active myeloma (P = 0.0007) but diffuse uptake was not (P = 0.15). Diffuse uptake alone, without focal uptake, was found in four of 19 scans with myeloma and in 10 of 20 without active myeloma, but was not significantly associated with absence of active myeloma (P = 0.06). Using the criteria of Pace et al. for positivity (diffuse activity >50% myocardial activity), we demonstrated improved specificity from 45% to 100%, but significantly impaired sensitivity for presence of myeloma (79% vs. 37%, P = 0.02). CONCLUSION: Our study thus illustrates that the presence of any focal uptake of MIBI is useful in indicating active myeloma whereas diffuse uptake is not.

Adolescent↗

PubMed2000

Measurements of nanometer scale interface diffusion between tungsten and niobium thin films using high frequency laser based ultrasound

This article presents the use of a quantitative analysis technique to describe time-resolved acoustic spectroscopy (high frequency laser based ultrasound) measurements of atomic diffusion on nanometer length scales occurring at the interface between sputter-deposited tungsten and niobium films. The extent of diffusion at the tungsten-niobium interface is determined by comparing experimental, simulated, and theoretical transfer functions between acoustic arrivals. The experimental and simulated transfer functions use the spectral content of successive reflected acoustic waves and the theoretical transfer function is based on the transfer matrix of an equivalent stratified interface region. This combination of theoretical, simulated, and experimental analyses makes it possible to separate signals with distinct differences between the as-deposited interface and those interfaces diffused to an experimentally determined 0.8-nm and 1.4-nm extent. Comparison of predicted and measured diffusion depths for this diffusion couple indicates that bulk diffusivities are not appropriate for describing nanometer scale interface diffusion.

Journal Article↗

PubMed2001

Normal brain maturation during childhood: developmental trends characterized with diffusion-tensor MR imaging.

PURPOSE: To characterize the maturational changes in water diffusion within central gray matter nuclei and central white matter pathways of the human brain by using diffusion-tensor magnetic resonance (MR) imaging. MATERIALS AND METHODS: Retrospective analysis of normal MR examination findings in 153 subjects (age range, 1 day to 11 years) referred for clinical neuroimaging was performed. All studies included diffusion tensor-encoded echo-planar MR imaging. Isotropic diffusion coefficient (D) and diffusion anisotropy (A(sigma)) were measured in the corpus callosum, internal capsule, caudate nucleus, lentiform nucleus, and thalamus. RESULTS: exhibited biexponential decay with age in gray and white matter regions, except for monoexponential decay in the genu of the corpus callosum. There was a steep nonlinear increase of A(sigma) in white matter tracts that paralleled the time course of the decline in D. In basal ganglia, only a small linear increase in A(sigma) was observed in patients. A(sigma) changes in the thalamus were intermediate between basal ganglia and white matter structures. CONCLUSION: Changes in magnitude and anisotropy of water diffusion follow stereotypical time courses during brain development that can be empirically described with multiexponential regression models, which suggests that quantitative scalar parameters derived from diffusion-tensor MR imaging may provide clinically useful developmental milestones for brain maturity.

Brain↗

PubMed2001

Reversible posterior leukoencephalopathy syndrome: evaluation with diffusion-tensor MR imaging.

PURPOSE: To characterize the changes in brain water diffusion caused by reversible posterior leukoencephalopathy syndrome (RPLS). MATERIALS AND METHODS: Twelve patients with the clinical features and conventional magnetic resonance (MR) imaging findings of RPLS underwent diffusion-tensor echo-planar MR imaging. The isotropic diffusion coefficient (D) and diffusion anisotropy (A(sigma)) were measured in posterior regions of diffusion abnormality and in anterior areas of normal-appearing brain. RESULTS: Across all 12 subjects, the mean D of (1.09 +/- 0.13 [SD]) x 10(-3) mm(2)/sec in affected posterior regions was 26% greater than its value of (0.87 +/- 0.07) x 10(-3) mm(2)/sec in normal-appearing anterior regions. The mean A(sigma) of 0.15 +/- 0.03 in posterior regions was 35% less than its value of 0.23 +/- 0.02 in anterior regions (t(11) = 9.58; P <.001). There was a significant inverse correlation between D and A(sigma) in posterior regions (r = -0.67; P <.018) but not in anterior regions (r = -0.12; P =.719). A follow-up study performed in one patient after resolution of symptoms documented reversal of elevated isotropic diffusion and at least partial recovery of anisotropy loss. CONCLUSION: The increased magnitude of brain water diffusion characteristic of RPLS is accompanied by reduced A(sigma). The magnitudes of these two effects are correlated and may be reversible. These observations support the proposal that vasogenic edema due to cerebrovascular autoregulatory dysfunction is the underlying pathophysiologic mechanism in uncomplicated RPLS.

Adult↗

PubMed1994

Diffusion nuclear magnetic resonance imaging in experimental stroke. Correlation with cerebral metabolites.

BACKGROUND AND PURPOSE: Diffusion-weighted nuclear magnetic resonance imaging has been shown to detect early ischemia-related alterations in experimental stroke. This raises the question of whether the observed increase in signal intensity is correlated with changes in cerebral metabolism. After middle cerebral artery occlusion, nuclear magnetic resonance diffusion images were recorded and compared with the regional concentration of cerebral metabolites and with histology of identical planes. METHODS: Seven anesthetized Fischer rats were subjected to permanent occlusion of the middle cerebral artery. T1, T2, and diffusion images (b factors ranging from 0 to 1500 s/mm2) were measured in three to five planes after 7 hours. Thereafter, brains were frozen in situ for histology and quantitative bioluminescence imaging of ATP, glucose, lactate, and for fluorescence imaging of tissue pH. RESULTS: Seven hours after middle cerebral artery occlusion, the apparent diffusion coefficient was reduced from 615 +/- 97 x 10(-6).mm2.s-1 (contralateral brain) to 359 +/- 42 x 10(-6).mm2.s-1 (ischemic brain; mean +/- SD, P < .01). A precise topical coincidence was demonstrated between changes in nuclear magnetic resonance diffusion images, pattern of histological damage, ATP-depleted areas, and local tissue acidosis, the lesion area amounting to between 24.1% and 27.6% of the hemisphere at the level of the caudate-putamen. The area of elevated brain lactate clearly exceeded the acidic core of the infarct and included the slightly alkaline border zone. CONCLUSIONS: The data demonstrate that after 7-hour middle cerebral artery occlusion, the reduction of the apparent diffusion coefficient in nuclear magnetic resonance diffusion images reflects precisely the region of histological injury, breakdown of energy metabolism, and tissue acidosis.

Adenosine Triphosphate↗

PubMed2006

Measurement and prediction of lateral diffusion within human sclera.

PURPOSE: Drug delivery via the sclera is a promising approach to retinal disorder treatments that require access to the posterior segment of the eye. To complement existing studies of transverse diffusion across the sclera, this study examined lateral diffusion within the sclera parallel to the scleral surface. METHODS: Using sulforhodamine as a model hydrophilic drug, rates of diffusion were measured in strips of human cadaveric sclera for up to 1 week. Data were analyzed with a mathematical model based on theoretical expressions for one-dimensional diffusion. RESULTS: Measurable amounts of sulforhodamine were detected at distances of 5 and 10 mm from the sulforhodamine donor reservoir at 4 hours and 3 days, respectively. The effective lateral diffusivity of sulforhodamine was determined to be 3.82 x 10(-6) cm2/s, which is similar in magnitude to the transverse diffusivity. The theoretical model agreed with experimental values with an average error of 39%. CONCLUSIONS: This study shows that the lateral diffusion of sulforhodamine in human sclera is slow and localizes to the site of administration.

Biological Transport↗

PubMed1990

Plaque fluid and diffusion: study of the cariogenic challenge by computer modeling.

Every cariogenic challenge involves a mixture of convective transport, diffusive transport, and biochemical reactions, plus physico-chemical reactions (including charge-coupling of diffusion), all of which together require numerical methods for their analysis. This presentation describes a one-dimensional finite-difference computer model of the cariogenic process, and some conclusions obtained from it. Sugar clearance from the mouth, together with site-dependent exchange between the bulk saliva and plaque surface via a salivary film, is combined with a finite-difference model of events occurring within the dental plaque. The latter includes: sugar diffusion and pH-dependent acid production; diffusion and dissociation equilibria for two acid end-products of fermentation and their anions (acetate and lactate); diffusion and dissociation equilibria of phosphate buffer; diffusion of potassium and chloride; diffusion of protons and simultaneous equilibration with fixed and mobile buffers. So that proper concentration distributions consistent with local charge neutrality can be ensured, an algorithm called Q-couple is used to impose charge-coupling between the fluxes of different ions including fixed charges. Mineral dissolution and precipitation are modeled as part of the same equilibrium calculations. The predictions of the model are compared with those of an earlier, much simpler one, in which fixed buffers were not included. It is shown that the known concentration of fixed buffer greatly extends the low pH of a Stephan curve. The isoelectric point of the plaque bacteria also appears to be of importance. The effects of various concentrations of mobile buffers, including acetate, are investigated. It is also shown that varying plaque/saliva contact over the known range derived from published studies has a profound effect on the modeled cariogenic challenge.

Computer Simulation↗

PubMed2003

Mass spectrometric analysis of electrophoretically separated allergens and proteases in grass pollen diffusates.

BACKGROUND: Pollens are important triggers for allergic asthma and seasonal rhinitis, and proteases released by major allergenic pollens can injure airway epithelial cells in vitro. Disruption of mucosal epithelial integrity by proteases released by inhaled pollens could promote allergic sensitisation. METHODS: Pollen diffusates from Kentucky blue grass (Poa pratensis), rye grass (Lolium perenne) and Bermuda grass (Cynodon dactylon) were assessed for peptidase activity using a fluorogenic substrate, as well as by gelatin zymography. Following one- or two-dimensional gel electrophoresis, Coomassie-stained individual bands/spots were excised, subjected to tryptic digestion and analysed by mass spectrometry, either MALDI reflectron TOF or microcapillary liquid chromatography MS-MS. Database searches were used to identify allergens and other plant proteins in pollen diffusates. RESULTS: All pollen diffusates tested exhibited peptidase activity. Gelatin zymography revealed high Mr proteolytic activity at approximately 95,000 in all diffusates and additional proteolytic bands in rye and Bermuda grass diffusates, which appeared to be serine proteases on the basis of inhibition studies. A proteolytic band at Mr approximately 35,000 in Bermuda grass diffusate, which corresponded to an intense band detected by Western blotting using a monoclonal antibody to the timothy grass (Phleum pratense) group 1 allergen Phl p 1, was identified by mass spectrometric analysis as the group 1 allergen Cyn d 1. Two-dimensional analysis similarly demonstrated proteolytic activity corresponding to protein spots identified as Cyn d 1. CONCLUSION: One- and two-dimensional electrophoretic separation, combined with analysis by mass spectrometry, is useful for rapid determination of the identities of pollen proteins. A component of the proteolytic activity in Bermuda grass diffusate is likely to be related to the allergen Cyn d 1.

Antigens, Plant↗

PubMed1987

Temperature affects the diffusion of small molecules through cytosol of fish muscle.

Undiluted cytosolic extracts were prepared from fast glycolytic muscle tissue of white perch (Morone americanus). Diffusion coefficients (D) through the cytosol preparations were estimated in vitro for a series of selected low molecular weight compounds using an experimental diffusion chamber. Determinations were made at 5 degrees and 25 degrees C to assess thermal sensitivity of the process. Non-metabolizable analogues of naturally occurring compounds were employed to avoid chemical alteration of solutes by the catalytically competent preparations during diffusion experiments. Kinematic viscosity of cytosolic extracts, which is a major determinant of diffusive resistance, increases from 2.94 +/- 0.06 to 5.35 +/- 0.02 X 10(-2) cm2 s-1 between temperatures of 25 degrees and 5 degrees C (Q10 = 1.35 +/- 0.01). The diffusion coefficients (D) of D-lactic acid are 2.26 +/- 0.84 and 0.79 +/- 0.15 X 10(-6) cm2s-1 at 25 degrees and 5 degrees C, respectively (Q10 = 1.84 +/- 0.36). The D values of 2-deoxyglucose are 2.87 +/- 1.01 and 1.22 +/- 0.36 X 10(-6) cm2s-1 at 25 degrees and 5 degrees C (Q10 = 1.75 +/- 0.54). The D values of Ca2+ are 2.47 +/- 0.28 and 1.09 +/- 0.36 X 10(-6) cm2s-1 at 25 degrees and 5 degrees C (Q10 = 2.04 +/- 0.36). The D values for the ATP analogue, AMP-PNP, are 0.87 +/- 0.33 and 0.81 +/- 0.15 X 10(-6) cm2s-1 at 25 degrees and 5 degrees C (Q10 = 0.98 +/- 0.12). AMP-PNP is the only compound tested which did not show significant thermal sensitivity of diffusion. Recently reported changes in muscle cell ultrastructure induced by temperature acclimation of fishes may serve to counteract the effect of temperature change on diffusion of key small molecules through the aqueous cytoplasm, thus maintaining flux rates between cellular compartments. These mechanisms may be of considerable import in achieving relative temperature independence of cellular function that is characteristic of many eurythermal aquatic animals.

Adenosine Triphosphate↗

PubMed2004

Clinical similarities and differences between human T-cell lymphotropic virus type 1-associated bronchiolitis and diffuse panbronchiolitis.

STUDY OBJECTIVES: Human T-cell lymphotropic virus type 1 (HTLV-1)-associated bronchiolitis and diffuse panbronchiolitis might overlap. We examined whether these conditions can be differentiated by comparing their clinical features and the effect of long-term macrolide treatment. PATIENTS AND METHODS: Fifty-eight Japanese patients, including 15 with HTLV-1-associated bronchiolitis and 43 with diffuse panbronchiolitis. Both conditions were clinically compared using the clinical criteria for diffuse panbronchiolitis, including findings from CT scans and BAL fluid testing. Pulmonary function, blood gas levels, and cold hemagglutinin (CHA) levels were assessed before and after long-term treatment with macrolides. Interleukin-2 receptor (IL-2R) expression in T cells obtained from the BAL fluid of patients with HTLV-1-associated bronchiolitis or diffuse panbronchiolitis was analyzed by flow cytometry. RESULTS: Clinical, laboratory, radiologic, and bacterial features were strikingly similar in both groups, except for the fact that patients with HTLV-1-associated bronchiolitis had a higher ratio of IL-2R-positive cells in the BAL fluid. The histopathologic features were also similar. Long-term treatment with macrolides improved PaO(2), FEV(1), and CHA in patients with HTLV-1-associated bronchiolitis to a lesser extent than in those with diffuse panbronchiolitis, and PaO(2) and FEV(1) in the group of patients with HTLV-1-associated bronchiolitis who had high IL-2R levels did not respond after therapy. CONCLUSIONS: These findings showed that the clinicopathologic features of the two conditions are quite similar, suggesting that diffuse panbronchiolitis is a chronic pulmonary manifestation of HTLV-1 infection. However, HTLV-1-associated bronchiolitis might be associated with conditions that are distinct from those of diffuse panbronchiolitis based on the different responses to macrolide treatment and the difference in the number of activated T cells bearing IL-2R in the lungs.

Bronchiolitis↗

PubMed1999

High-resolution CT findings of diffuse bronchioloalveolar carcinoma in 38 patients.

OBJECTIVE: The purpose of this study was to analyze the high-resolution CT features of diffuse bronchioloalveolar carcinoma and determine the useful findings in differential diagnosis. MATERIALS AND METHODS: High-resolution CT scans of 38 patients with pathologically proven diffuse bronchioloalveolar carcinoma were reviewed. Sequential CT scans were obtained in 15 patients. The high-resolution CT findings were compared with those of eosinophilic pneumonia (n = 22), multiple pulmonary metastases (n = 12), and tuberculosis (bronchogenic: n = 22; miliary: n = 12). RESULTS: High-resolution CT findings of diffuse bronchioloalveolar carcinoma included ground-glass opacity (n = 29), consolidation (n = 29), nodules (n = 28), centrilobular nodules (n = 26), peripheral distribution (n = 19), and air bronchogram (n = 18). According to the major features, high-resolution CT findings of diffuse bronchioloalveolar carcinoma could be classified into three patterns: predominantly ground-glass (n = 4), consolidative (n = 22), and multinodular (n = 12). Most patients with diffuse bronchioloalveolar carcinoma had a mixture of these findings. The frequency of findings of diffuse bronchioloalveolar carcinoma on high-resolution CT was not different from that of tuberculosis, but the predominant distribution of the nodules and areas of ground-glass attenuation differed between the two. Difference in distribution between bronchioloalveolar carcinoma and bronchogenic tuberculosis included ground-glass opacity remote from the consolidation and a lower lung predominance. CONCLUSION: Although these high-resolution CT findings are not specific, the combination of consolidation and nodules and the coexistence of centrilobular nodules and remote areas of ground-glass attenuation are characteristic of diffuse bronchioloalveolar carcinoma.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed2000

Quantitative comparison of intrabrain diffusion in adults and preterm and term neonates and infants.

OBJECTIVE: Quantitative measurements of mean water diffusivity (D(av)) were made in human neonates, infants, and adults to assess changes in brain tissue that occur with maturation. SUBJECTS AND METHODS: Values of D(av) were obtained by calculating the average of the diffusion measurements made with diffusion-sensitizing gradients placed along three orthogonal directions. The mean diffusivity, a rotationally invariant determination of apparent diffusion coefficient, was measured in five healthy prematurely born neonates and infants, in 10 healthy term neonates and infants, and in five adults. RESULTS: Values of D(av) were found to decrease with maturation in most parts of the brain. In prematurely born neonates and infants with a postmenstrual age (postgestastional age + postnatal age) under 36 weeks, the average value of D(av) in frontal white matter was 1.90 x 10(-3) mm2 sec(-1). The corresponding value was measured as 1.62 x 10(-3) mm2 sec(-1) in neonates and infants born at term with a postnatal age of no more than 43 days and 0.79 x 10(-3) mm2 sec(-1) in the adult brain. CONCLUSION: Values of D(av) are known to decrease in neonates and young infants in the period immediately after ischemic insult. This decrease and the associated increase in signal intensity seen on diffusion-weighted imaging have been used to monitor ischemic brain injury in neonates and infants. Therefore, the decrease in D(av) that occurs with maturation, which we report in this study, must be considered if quantitative diffusion measurements are used to assess ischemic neonatal brain injury.

Adult↗

PubMed2000

Quantitative diffusion measurements in focal multiple sclerosis lesions: correlations with appearance on TI-weighted MR images.

OBJECTIVE: Relative hypointensity on T1-weighted MR imaging has been suggested as a putative disability marker. The purpose of our study was to determine if there are quantifiable diffusion differences among focal multiple sclerosis lesions that appear differently on conventional T1-weighted MR images. We hypothesized that markedly hypointense lesions on unenhanced T1-weighted images would have significantly increased diffusion compared with other lesions, and enhancing portions of lesions would have different diffusion compared with nonenhancing lesions. SUBJECTS AND METHODS: Average apparent diffusion coefficient (ADC) was calculated for 107 lesions identified on T2-weighted images in 16 patients with multiple sclerosis and was compared with the ADC of normal white matter in 16 age- and sex-matched control subjects. Seventy-five nonenhancing lesions (29 isointense, 46 hypointense) and 32 enhancing lesions (6 isointense, 26 hypointense) were categorized on the basis of unenhanced T1-weighted MR imaging. RESULTS: Hypointense and isointense nonenhancing lesions both showed significantly higher ADC than normal white matter (p < 0.0001). Hypointense nonenhancing lesions showed higher ADC values than isointense nonenhancing lesions (p < 0.0001). Diffusion in enhancing portions of enhancing lesions was decreased when compared with nonenhancing portions. CONCLUSION: Quantitative diffusion data from MR imaging differ among multiple sclerosis lesions that appear different from each other on T1-weighted images. These quantitative diffusion differences imply microstructural differences, which may prove useful in documenting irreversible disease.

Adolescent↗

PubMed1992

Diffuse brain swelling in severely head-injured children. A report from the NIH Traumatic Coma Data Bank.

In this study, data were prospectively collected from 753 patients (111 children and 642 adults) with severe head injury and examined for evidence of diffuse brain swelling and its association with outcome. Diffuse brain swelling occurred approximately twice as often in children (aged 16 years or younger) as in adults. A high mortality rate (53%) was found in these children, which was three times that of the children without diffuse brain swelling (16%). Adults with diffuse brain swelling had a mortality rate (46%) similar to that of children, but only slightly higher than that for adults without diffuse brain swelling (39%). When the diagnosis of diffuse brain swelling was expanded to include patients with diffuse brain swelling plus small parenchymal hemorrhages (less than 15 cu cm), these mortality rates were virtually unchanged.

Adolescent↗

PubMed1996

A model of diffuse traumatic brain injury in the immature rat.

Diffuse cerebral swelling after severe traumatic brain injury (TBI) develops more commonly in children than adults; however, models of diffuse brain injury in immature animals are lacking. The authors developed a new model of diffuse severe TBI in immature rats by modifying a recently described closed head injury model for adult rats. A total of 105 Sprague-Dawley immature rats (17 days old; average weight 38.5 +/- 5.46 g) were subjected to head impact using variable weights (0 g (sham), 75 g, 100 g, or 125 g) delivered from a height of 2 m onto a metal disk cemented to the intact cranium. Mortality, physiological and neurological parameters (from early reflex recovery to escape), and early histopathological changes were assessed. During the acute period after severe injury (SI) (100 g delivered from a height of 2 m; 50 rats), apnea was frequently observed and the mortality rate was 38%. Neurological recovery was complete in the sham-injured animals (11 rats) by 4.1 +/- 0.23 minutes (mean +/- standard error of the mean), but was delayed in both moderately injured (MI) (75 g/2 m; 11 rats) (14.97 +/- 3.99 minutes) and SI (20.57 +/- 1.31 minutes (p < 0.05)) rats. In the first 24 hours, the sham-injured animals were more active than the injured ones as reflected by a greater net weight gain: 2.9 +/- 1.0 g, 1.2 +/- 1.6 g, and -0.6 +/- 2.1 g in sham-injured, MI, and SI animals, respectively. Immediately after injury, transient hypertension (lasting < 15 seconds) was followed by hypotension (lasting < 3 minutes) and loss of temperature regulation. Both injuries also induced apnea (0.75 +/- 0.7 minutes and 1.27 +/- 0.53 minutes in MI and SI groups, respectively), which either resolved or deteriorated to death. Intubation and assisted ventilation in animals with SI for 9.57 +/- 3.27 minutes in the peritrauma period eliminated mortality (p < 0.05, intubated vs. nonintubated). Histologically, after SI, there was diffuse edema throughout the corpus callosum below the region of injury and in the thalami. Other injuries included neuronal death in the deep nuclei, bilateral disruption of CA3, diffuse subarachnoid hemorrhage, and, in some, ventriculomegaly. Following a diffuse TBI in immature rats, SI produced a mortality rate, neurological deficit, and histological changes similar to those previously reported for an injury resulting from a 450-g weight dropped from 2 m in adult rats. A graded insult was achieved by maintaining the height of the weight drop but varying the weights. Weight loss, acute physiological instability, and acute neurological deficits were also indicative of an SI. Mortality was eliminated when ventilatory support was used during the peritrauma period. This model should be useful in studying the response of the immature rat to diffuse severe TBI.

Animals↗

PubMed1999

[A case of medial medullary syndrome detected by diffusion-weighted magnetic resonance imaging].

We report an 84-year-old woman with medial medullary syndrome diagnosed by diffusion-weighted magnetic resonance imaging (MRI). She was admitted because of left hemiparesis and hypesthesia. T2-weighted and diffusion-weighted MRI showed a high signal lesion at the right medial medulla oblongata 10 days after the onset. It is well known that diffusion-weighted MRI is useful for detecting supratentrial cerebral ischemic lesions in the extremely acute stage. However, to our knowledge, there have been only a few reports of diffusion-weighted MRI in patients with ischemic stroke of the medulla oblongata. Normal nerve fibers in the direction perpendicular to the motion-probing gradient (MPG) shows a high signal by diffusion-weighted MRI (anisotropy of apparent diffusion cofficient [ADC]). Normal nerve fibers in the pyramidal tract of medulla oblongata also shows a high signal when the MPG pulse is applied in the x and y directions. We solved this problem by using isotropic diffusion-weighted imaging and were able to detect ischemic lesion of medial medullary infarction in the acute phase.

Aged↗

PubMed1999

[Diffuse jejuno-ileitis of Crohn's disease: a separate form of the disease?].

BACKGROUND AND AIMS: Diffuse jejuno-ileitis of Crohn's disease may be a homogeneous clinical subgroup. The aim of this work was to compare the demographic and clinical data at diagnosis and the initial treatments of patients with diffuse jejuno-ileitis of Crohn's disease and to the ones without this localization. PATIENTS AND METHODS: For demographic and clinical studies, 48 (32M/16F) incident cases of diffuse jejuno-ileitis of Crohn's disease diagnosed between 1988 and 1994 in the EPIMAD register were compared with 96 (48M/48F) controls diagnosed the same year. As far as for the therapeutic management, the 48 incident cases were compared with 48 controls. RESULTS: Diffuse jejuno-ileitis constituted 3.3% of the total incident cases. Median age at diagnosis was significantly lower (20 vs 23 years, P = 0.01) and an upper digestive involvement was more frequent (56% vs 34%, P = 0.03) in patients with diffuse jejuno-ileitis. These patients were more often treated by total parenteral nutrition (43.8% vs 19.6%, P = 0.01) or azathioprine (50% vs 20.8%, P = 0.005). Azathioprine was also introduced earlier (20.7 vs 40.3 months, P = 0.009). Surgery for resection was less often required in diffuse jejuno-ileitis than in controls (65.2% vs 99.8%, P = 0.02) while more stricturoplasties were performed (52.9% vs 10%, P = 0.003); overall surgical rates did not significantly differ in the 2 groups. CONCLUSION: Our series suggest that diffuse jejuno-ileitis of Crohn's disease is a subgroup of patients characterized by a young age at diagnosis, with more frequent and earlier requirement for azathioprine.

Adolescent↗