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PubMed1970

Cellular Responses of Mice to Diffusion Chambers I. Reactions to Intraperitoneal Diffusion Chambers Containing Listeria monocytogenes and to Bacteria-Free Chambers.

Diffusion chambers made with membranes having a pore size of 0.22 mum were implanted in the peritoneal cavities of mice. Chambers that contained no cells induced splenic lymphoreticular hyperplasia and a proliferation of fibroblasts around the chambers. When the chambers contained the bacterium, Listeria monocytogenes, there was strong and continuous chemotaxis of phagocytic cells to the membrane surface. The tendency to incite fibrosis around the chambers containing bacteria produced a tissue reaction resembling a chronic abscess or granuloma. The important difference from a natural lesion was the prevention of direct parasite-host cell interactions. In studies on the pathogenesis of long persisting host-parasite relationships, one might successfully use diffusion chambers to investigate the role of humoral antimicrobial substances as well as the effects of chronic inflammation, with its local concentration of metabolic products and constituents of phagocytic cells. On the other hand, the presence of diffusion chambers in the tissues is an abnormal situation and changes arising from their presence may complicate the interpretations of some experiments.

Journal Article↗

PubMed2003

In vivo breast imaging with diffuse optical tomography based on higher-order diffusion equations.

We report on in vivo absorption and scattering imaging of a human breast cyst and implant, using a reconstruction algorithm based on our third-order diffusion equations. To validate these in vivo images, a series of phantom experiments were conducted, in which we used low-absorbing and low-scattering heterogeneities to mimic a breast cyst or implant. These heterogeneities or targets were composed of pure water or a mixture of water and very dilute Intralipid (0.05% and 0.1%). The phantom experiment confirmed the quantitative imaging capability of our improved algorithm for reconstructing heterogeneities where the conventional diffusion approximation is inadequate. Pilot clinical results from female volunteers indicate that enhanced diffuse optical tomography can quantitatively image findings such as breast cysts or implants in which the absorption and scattering coefficients are usually low.

Adult↗

PubMed2003

Segment identification of a ligand binding with a protein receptor using multidimensional T1rho-, diffusion-filtered and diffusion-ordered NOESY experiments.

Multidimensional T1rho-, diffusion-filtered and diffusion-ordered NOESY techniques were applied to identify segments of a ligand binding with a protein receptor. These experiments can easily provide intermolecular NOEs of the complex, which are of great significance for characterizing the binding epitopes of a ligand. This information cannot be obtained by high-throughput 1D NMR experiments, used for determining the binding affinity, although multidimensional NMR experiments require more experiment time. The present results indicate that the current experiments using T1rho- and diffusion-edited techniques are very suitable for identifying segments of a ligand binding with a protein receptor in the drug discovery process.

Binding Sites↗

PubMed1999

Radiological diagnosis of acute stroke. Comparison of conventional MR imaging, echo-planar diffusion-weighted imaging, and spin-echo diffusion-weighted imaging.

PURPOSE: To compare conventional MR imaging, echo-planar diffusion-weighted imaging (EP-DWI) and spin-echo diffusion-weighted imaging (SE)-DWI at radiological diagnosis of acute stroke. MATERIAL AND METHODS: Twenty-seven patients (30-85 years old) were examined. Clinical examination was performed before MR imaging. All MR examinations were assessed by an experienced neuroradiologist blinded to clinical findings. RESULTS: In EP-DWI, every patient had a lesion corresponding to the clinical findings. EP-DWI was used as the gold standard. In conventional PD+T2 imaging, 23/59 focal lesions were interpreted as acute, which was false in 11 lesions, and 36/59 lesions were considered to be old, 6 were in fact acute. Nine acute lesions were only detected retrospectively and 12 acute lesions were not detected at all on PD+T2. SE-DWI including the apparent diffusion coefficient correlated fairly well with EP-DWI but the procedure was impractical. CONCLUSION: EP-DWI is reliable for diagnosis of early ischemic stroke, while SE-DWI performs reasonably well. Conventional PD+T2 imaging is not reliable for diagnosis of early ischemia.

Acute Disease↗

PubMedDate not supplied

Peroxisomal biogenesis disorder: comparison of conventional MR imaging with diffusion-weighted and diffusion-tensor imaging findings.

BACKGROUND AND PURPOSE: Peroxisomal biogenesis disorders (PBDs) refer to a group of disorders of peroxisomal biogenesis causing neuronal migration disorder, delayed myelination, and demyelination. The aim of this study was to evaluate the added value of diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) compared with that of conventional T2-weighted imaging in assessing the extent of white matter damage in patients with PBDs. METHODS: Three patients (aged 12, 16, and 80 months) with PBD (type 1 protein targeting sequence [PTS1]) and three age-matched control subjects underwent MR imaging on a 1.5-T system. The protocol included axial T2-weighted, DWI, and DTI sequences. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) changes were calculated using regions of interest at several predefined white matter areas and compared with those of age-matched control subjects. Color-coded maps were obtained to visualize the range of FA values. RESULTS: On the T2-weighted images, one patient revealed severe hypomyelination throughout the brain; the two other patients showed focal abnormal high-signal-intensity areas. All patients had significantly decreased FA values in white matter areas that appeared abnormal on the T2-weighted images. In two of the three patients, significant FA reduction was also found in normal-appearing white matter. The ADC values of the patients were significantly increased compared with those of the age-matched controls. CONCLUSION: Although based on a small number of patients, our data suggest that DWI and DTI can be used to characterize and quantify white matter tract injury in patients with PBD-PTS1. Furthermore, our data suggest that these techniques have the potential to identify neurodegenerative changes not yet visible on T2-weighted images.

Child↗

PubMed1988

Non-Hodgkin's lymphoma in children; diffuse lymphoblastic histology; diffuse non-lymphoblastic histology; LSA2-L2 experience.

The majority of the patients with non-Hodgkin's lymphoma present with extensive disease at diagnosis. Extranodal is the most common primary site and Non-lymphoblastic histology is the most common histological subtype in pediatric lymphomas of which diffuse histiocytic is certainly the most common of the group, second only to diffuse lymphoblastic histology. Certain histological subtypes are associated with certain primary sites. The LSA2-L2 has been shown in this group to be as effective for lymphoblastic lymphoma as for non-lymphoblastic lymphomas, a slightly lower disease-free survival is due to the fact that, in this group, certain factors such as initial central nervous system involvement, initial bone marrow involvement, and high serum lactic dehydrogenase levels seem to play an important role in prognosis. The comparison of the disease-free survival for the two major subgroups, lymphoblastic and non-lymphoblastic shows the following: For primary intra-abdominal disease, in which clearly the majority belong to the Non-lymphoblastic histology, with a total of 50 patients, the disease-free survival was 67%; for lymphoblastic histology with 5 patients, the actuarial disease-free survival was 100%. For primary mediastinal with 24 patients with diffuse lymphoblastic histology the disease-free survival was 95%, and in 13 patients with Non-lymphoblastic histology a disease-free survival of 83%.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗

PubMedDate not supplied

Differential diagnosis of diffuse choroidal atrophies. Diffuse choriocapillaris atrophy, choroideremia, and gyrate atrophy of the choroid and retina.

Three young children showed a similar fundus appearance of sharply defined, yellowish-white, patchy or geographic atrophy of the retina and choroid and visible large choroidal vessels in almost the entire fundus. Fluorescein angiography disclosed atrophy of the retinal pigment epithelium and loss of choriocapillaris. Their visual functions and electrophysiologic findings were also similar. Family A was diagnosed as having diffuse choriocapillaris atrophy with autosomal dominant inheritance; family B, choroideremia with X-linked recessive heredity; and family C, gyrate atrophy of the choroid and retina with hyperornithinemia and autosomal recessive transmission. It became evident that diffuse choriocapillaris atrophy, choroideremia, and gyrate atrophy sometimes show a similar fundus appearance. Fluorescein angiography, serum ornithine levels, and family history were particularly helpful to differentiate these diffuse choroidal atrophies.

Adolescent↗

PubMed1982

Diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA). Quantification of antigen by diffusion over an antibody-coated surface.

The diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA) has previously been used for quantification of antibodies. In the present study, using bovine serum albumin as antigen and a corresponding rabbit antiserum as antibody source, the DIG-ELISA principle was used for quantification of antigen. Antibodies were immobilized on a plastic surface, over which the antigen was allowed to diffuse in an agarose gel. The antigen-antibody reaction zones were then detected by binding of an enzyme-labelled antibody directed against the antigen. The enzyme-substrate reaction, yielding a coloured reaction product, was visualized in a substrate-containing gel. The density and quality of immobilized antibody on the surface was found to be critical. Reproducible results were obtained only when antibodies purified with affinity chromatography on immobilized antigen were used. After 46 h of diffusion the diameter of the reaction zones was directly proportional to the logarithm of the antigen concentration in the range 0.4 mg/1-1 g/1. The variability of the method (CV) was 3%.

Animals↗

PubMed1977

Proliferation of diffusion chamber colony-forming units (CFUD) in cultures of normal human bone marrow in diffusion chambers in mice.

Normal human bone marrow contains cells capable of forming colonies of hemopoietic cells in fibrin clots in diffusion chambers implanted intraperitoneally (i.p.) into irradiated mice. The present paper describes the proliferation of such colony-forming units (CFUD) in cultures in vivo. Cells harvested from diffusion chambers after 1-14 days of culture in 450-R irradiated mice contained CFUD, which formed neutrophilic, eosinophilic, or megakaryocytic colonies when tested by secondary culture in fibrin clot chambers. When bone marrow was precultured in irradiated mice at a concentration of 10(6) cells per chamber, an initial fall in the number of neutrophilic CFUD was observed. This decrease was followed by an increase to a maximum at day 2, and then a secondary decrease. The number of neutrophilic CFUD recovered after 2 days of preculture in irradiated mice varied between 60% and 250% of the number present before preculture. Preculture in nonirradiated mice resulted in a significantly lower recovery of neutrophilic CFUD. In vitro treatment of bone marrow cells with hydroxyurea (OHU) after 2 days of preculture in irradiated mice resulted in a 68% +/- 5% reduction in the number of neutrophilic CFUD. In contrast, OHU had no similar effect on precultures from nonirradiated mice. Both the recovery and sensitivity to OHU of eosinophilic CFUD were independent of host irradiation. Similarly, no effect of host irradiation on the recovery or the 3H-thymidine (3HTdR) labeling index of morphologically recognizable granulocytic cells was observed at day 2. The data suggest an effect of humoral host factor(s) on the proliferation of early precursor cells, which are or become committed to differentiate into the neutrophilic pathway in diffusion chambers.

Animals↗

PubMed1996

[Diffuse ventricular enlargement outlines the late outcome of diffuse axonal brain injury].

Clinical significance of ventriculomegaly after severe head trauma has not been fully explored yet. We analyzed hospital records of 53 cases of diffuse axonal injury and 7 cases of brain concussion together. The follow-up periods ranged from 6 months to 8 years (average 25 months). Four patients underwent CSF shunting without noticeable effect. We classified their outcome according to our modification of the Glasgow outcome scale: vegetated, severe, moderate, mild, fair, and good. We reviewed initial (within 12 hours after injury) CT scans and late (3 to 6 months after injury) CT scans or MRI's. We measured the ratio of the third ventricular width to the inner diameter of the skull on the axial view. We computed the lateral ventricular volume by our newly-devised method which took the partial volume phenomenon into account. Temporary extracerebral fluid accumulation was noted mostly within 3 months after injury in 25 of 39 cases in the mild level or above, and 2 of the 9 fair or good level cases. Ventriculomegaly occurred early and stabilized around the 3 month period. We found the differences between the late and the initial values of the third ventricular width (%) and the lateral ventricular volume (cc) highly correlated with our outcome scale (Spearman's correlation coefficient rs = 0.531, 0.676, respectively with p < 0.001 unanimously). We found the late values themselves of the third ventricular width and the lateral ventricular volume highly correlated with our outcome scale (rs = 0.575, 0.650, respectively with p < 0.001 unanimously). These 4 parameters were also highly correlated with the duration of the initial unconsciousness (LOC). Thus, posttraumatic diffuse ventriculomegaly affecting the third ventricle as well should outline the late outcome of diffuse axonal injury. Both the ventriculomegaly and the late outcome should be roughly predicted by the duration of the initial unconsciousness.

Adolescent↗

PubMed1976

A diffusible stimulator of eosinophilopoiesis produced by lymphoid cells as demonstrated with diffusion chambers.

Previous experiments have indicated that eosinophilopoiesis is stimulated in lymphoid cell-dependent eosinophil responses to certain antigens. In order to study if the potential for this stimulation of eosinophilopoiesis is a function of lymphoid cells and can be expressed on challenge with the eosinophilia-inducing antigen, the diffusion chamber technique for the culture in vivo of murine hemopoietic cells has been modified. A quadrachamber diffusion assembly allows for the simultaneous maintenance in the same host of four cell populations, pairs of which are separated by a cell-impermeable Millipore diffusion membrane of defined porosity. Spleen cells for chambers were from normal mice and mice primed with tetanus toxoid; secondary challenge induces eosinophilia. These spleen cells were placed transfilter from isogeneic bone marrow cells and cultured in vivo for 6 days in normal mice that received tetanus toxoidintraperitoneally following chamber-assembly implant. The marrow cell transfilter from spleen cells of primed-donor origin exhibited significantly greater eosinophilopoiesis than contiguous-chamber marrow transfilter from normal spleen cells. Such stimulated eosinophilopoiesis was independent of total chamber marrow cellularity. The data indicated that antigen-stimulated lymphoid cells may be the source of an eosinophilopoietic factor.

Animals↗

PubMed2004

Diffusion-weighted imaging of the parotid gland: Influence of the choice of b-values on the apparent diffusion coefficient value.

PURPOSE: To determine how the ADC value of parotid glands is influenced by the choice of b-values. MATERIALS AND METHODS: In eight healthy volunteers, diffusion-weighted echo-planar imaging (DW-EPI) was performed on a 1.5 T system, with b-values (in seconds/mm2) of 0, 50, 100, 150, 200, 250, 300, 500, 750, and 1000. ADC values were calculated by two alternative methods (exponential vs. logarithmic fit) from five different sets of b-values: (A) all b-values; (B) b=0, 50, and 100; (C) b=0 and 750; (D) b=0, 500, and 1000; and (E) b=500, 750, and 1000. RESULTS: The mean ADC values for the different settings were (in 10(-3) mm2/second, exponential fit): (A) 0.732+/-0.019, (B) 2.074+/-0.084, (C) 0.947+/-0.020, (D) 0.890+/-0.023, and (E) 0.581+/-0.021. ADC values were significantly (P <0.001) different for all pairwise comparisons of settings (A-E) of b-values, except for A vs. D (P=0.172) and C vs. D (P=0.380). The ADC(B) was significantly higher than ADC(C) or ADC(D), which was significantly higher than ADC(E). ADC values from exponential vs. logarithmic fit (P=0.542), as well as left vs. right parotid gland (P=0.962), were indistinguishable. CONCLUSION: The ADC values calculated from low b-value settings were significantly higher than those calculated from high b-value settings. These results suggest that not only true diffusion but also perfusion and saliva flow may contribute to the ADC.

Adult↗

PubMedDate not supplied

From the diffusion coefficient to the diffusion tensor.

With diffusion tensor MRI one has access to the organization in space of tissue microstructural components. This outstanding potential adds, however, another layer of complexity to the diffusion MRI data acquisition and analysis processes. Over the last few years many articles have been published dealing with those matters. This special issue is thus timely to provide readers with the synthesis and the overall viewpoints from leading contributors to the field.

Anisotropy↗

PubMed2005

Optimized diffusion-weighted spectroscopy for measuring brain glutamate apparent diffusion coefficient on a whole-body MR system.

A diffusion-weighted stimulated echo acquisition mode sequence was implemented in order to measure the glutamate apparent diffusion coefficient (ADC) in the monkey brain on a whole-body 3 T system. TE and TM were adjusted for maximizing glutamate signal intensity. Glutamate ADC was measured in a 5.8 mL voxel made of gray and white matter in macaque monkeys. The effect of post-processing on the estimated ADC was carefully assessed and appeared to be critical. Individual scan phasing and macromolecule subtraction corrected for approximately 25% and approximately 15% biases in glutamate ADC, respectively. Proper data processing yielded ADC values of 0.21 +/- 0.03 microm(2)/ms for glutamate, 0.15 +/- 0.04 microm(2)/ms for N-acetylaspartate + N-acetylaspartylglutamate, 0.12 +/- 0.03 microm(2)/ms for creatine, 0.11 +/- 0.05 microm(2)/ms for choline and 0.18 +/- 0.04 microm(2)/ms for myo-inositol.

Animals↗

PubMed2004

Glucocorticoid treatment of brain tumor patients: changes of apparent diffusion coefficient values measured by MR diffusion imaging.

Glucocorticoids (GCC) generally are administered to patients with brain tumors to relieve neurological symptoms by decreasing the water content in a peritumoral zone of edema. We hypothesized that diffusion imaging and apparent diffusion coefficient (ADC) values could detect subtle changes of water content in brain tumors and in peritumoral edema after GCC therapy. The study consisted of 13 patients with intra-axial brain tumor, and ADC was measured in the tumor, within peritumoral edema, and in normal white matter remote from the tumor before and after GCC therapy. ADC also was measured in normal white matter in four control patients with no intracranial disease who were treated with GCC for other indications. Conventional MR images showed no visually evident interval change in tumor size or the extent of peritumoral edema in any subject after GCC therapy, which nonetheless resulted in a decrease in mean ADC of 7.0% in tumors (P < 0.05), 1.8% in peritumoral edema (P > 0.05, not significant) and 5.8% in normal white matter (P < 0.05). In patients with no intracranial disease, GCC therapy decreased mean ADC in white matter by 5.4% (P < 0.05). ADC measurement can demonstrate subtle changes in the brain after GCC therapy that cannot be observed by conventional MR imaging. Measurement of ADC proved to be a sensitive means of assessing the effect of GCC therapy, even in the absence of visually discernible changes in conventional MR images.

Adult↗

PubMed2005

Brain MR diffusion tensor imaging and fibre tracking to differentiate between two diffuse axonal injuries.

We report here two cases of diffuse axonal injury (DAI) studied by MR diffusion tensor imaging (DTI) and fibre tracking (FT) focused on the corpus callosum. In one case, DTI and FT pattern matched the diagnosis of broken white matter tracts. In the other case there was a discrepancy between DTI and FT data that showed unaltered white matter tracts with the presence of intra-cellular oedema. These data suggested that DTI and FT are able to differentiate between traumatic cytotoxic oedema and broken fibres in the case of DAI.

Adult↗

PubMed2005

Conspicuity of diffuse axonal injury lesions on diffusion-weighted MR imaging.

OBJECTIVE: (1) To detect diffuse axonal injury (DAI) lesions by diffusion-weighted imaging (DWI), as compared with fluid-attenuated inversion recovery (FLAIR) imaging and (2) to evaluate hemorrhagic DAI lesions by b0 images obtained from DWI, as compared with gradient-echo (GRE) imaging. METHODS: We reviewed MR images of 36 patients with a diagnosis of DAI. MR imaging was performed 20 h to 14 days (mean, 3.7 days) after traumatic brain injury. We evaluated: (1) conspicuity of lesions on DWI and FLAIR and (2) conspicuity of hemorrhage in DAI lesions on b0 images and GRE imaging. RESULTS: DWI clearly depicted high-signal DAI lesions. The sensitivity of DWI to lesional conspicuity in DAI lesions was almost equal to that of FLAIR. The sensitivity of b0 images to identification of hemorrhagic DAI lesions was inferior to that of GRE. CONCLUSION: DWI is as useful as FLAIR in detecting DAI lesions. GRE imaging is still the superior tool for the evaluation of hemorrhagic DAI.

Adolescent↗

PubMed2006

Role of diffusion-weighted magnetic resonance imaging in diffuse axonal injury.

PURPOSE: To determine whether the signal changes on magnetic resonance imaging (MRI), including fluid attenuated inversion recovery (FLAIR), T2*-weighted gradient echo (GE) imaging, and diffusion-weighted imaging (DWI) in diffuse axonal injury (DAI) patients correlate with the clinical outcome. MATERIAL AND METHODS: We diagnosed patients with DAI based on the following criteria: 1) a loss of consciousness from the time of injury that persisted beyond 6 h; 2) no apparent hemorrhagic contusion on computed tomography (CT); 3) the presence of white matter injury on MRI. Twenty-one DAI patients were analyzed (19 M, 2 F, mean age 34 years) with MRI (FLAIR, T2*-weighted GE imaging, and DWI). RESULTS: 325 abnormalities were detected by MRI within a week after injury. The T2*-weighted GE imaging was significantly more sensitive than FLAIR and DWI in diagnosing DAI. DWI detected only 32% of all lesions, but could depict additional shearing injuries not visible on either T2*-weighted GE imaging or FLAIR. The mean number of lesions in brainstem detected by DWI in the favorable group (good recovery/moderately disabled) was significantly smaller than in the unfavorable group (severely disabled/vegetative survival/death). This trend was not observed on the T2*-weighted GE imaging and FLAIR findings. CONCLUSION: DWI cannot detect all DAI-related lesions, but is a potentially useful imaging modality for both diagnosing and assessing patients with DAI.

Adolescent↗