Evaluation of giant arachnoid granulations with high-resolution 3D-volumetric MR sequences at 3T.

PURPOSE: To evaluate the contribution to the diagnosis of the giant arachnoid granulations (AGs) of three-dimensional (3D) high-resolution magnetic resonance (MR) imaging sequences such as T2-weighted sampling perfection with application optimized contrasts using different flip-angle evolution (SPACE) and post-contrast T1-weighted magnetization prepared rapid gradient echo (MPRAGE). MATERIALS AND METHODS: Patients with 45 giant AGs were included in this retrospective study. All the patients were performed 3D T2-weighted SPACE and contrast enhanced MR venography sequences, as well as conventional cerebral MR imaging sequences. Post-contrast T1 weighted MPRAGE sequence were performed on 38/45 patients. All cerebral MR examinations were reviewed by the 2 neuroradiologists. Each GA was evaluated carefully to assess location and mean diameter. RESULTS: The most common location for giant AGs was at both transverse sinuses. Fluid signal feature within the giant AGs was not isointense to CSF on SE T1 and FLAIR MR imaging in 32 of 45 giant AGs. There were cerebral herniation into AG in 10 (22.2 %) of 45 giant AGs. 33 (73.3 %) of 45 giant AGs had central vein finding into AG in contrast enhanced MR venography. Signal void phenomenon into AG in 3D T2-weighted SPACE MR sequence was identified in 28 (62.2 %) of 45 giant AGs. CONCLUSIONS: Fluid within giant AGs had no completely CSF-like signal intensity on conventional and 3D high-resolution MR imaging sequences. Majority of CSF-incongruent fluid within giant AGs on conventional sequences is mostly due to intra-AG CSF flow.

Impaired wound healing in mice deficient in a matricellular protein SPARC (osteonectin, BM-40).

BACKGROUND: SPARC is a matricellular protein involved in cell-matrix interactions. From expression patterns at the wound site and in vitro studies, SPARC has been implicated in the control of wound healing. Here we examined the function of SPARC in cutaneous wound healing using SPARC-null mice and dermal fibroblasts derived from them. RESULTS: In large (25 mm) wounds, SPARC-null mice showed a significant delay in healing as compared to wild-type mice (31 days versus 24 days). Granulation tissue formation and extracellular matrix protein production were delayed in small 6 mm SPARC-null wounds initially but were resolved by day 6. In in vitro wound-healing assays, while wild-type primary dermal fibroblasts showed essentially complete wound closure at 11 hours, wound closure of SPARC-null cells was incomplete even at 31 hours. Addition of purified SPARC restored the normal time course of wound closure. Treatment of SPARC-null cells with mitomycin C to analyze cell migration without cell proliferation showed that wound repair remained incomplete after 31 hours. Cell proliferation as measured by 3H-thymidine incorporation and collagen gel contraction by SPARC-null cells were not compromised. CONCLUSIONS: A significant delay in healing large excisional wounds and setback in granulation tissue formation and extracellular matrix protein production in small wounds establish that SPARC is required for granulation tissue formation during normal repair of skin wounds in mice. A defect in wound closure in vitro indicates that SPARC regulates cell migration. We conclude that SPARC plays a role in wound repair by promoting fibroblast migration and thus granulation tissue formation.

Use of anti-basement membrane antibodies to distinguish blood vessel capillaries from lymphatic capillaries.

A new method has been developed for identifying blood vessel capillaries and distinguishing them from lymphatic capillaries. Highly purified antibodies to two ubiquitous components of basement membrane--Type IV collagen and laminin--were applied to fresh-frozen and formalin-fixed tissue sections rich in blood vessel capillaries (granulation tissue), rich in lymphatic channels (small intestine and mesentery), and rich in both (skin, lung, and breast). Staining patterns were evaluated using standard immunofluorescence and immunoperoxidase techniques. Blood vessel capillaries contained intact basement membranes with linear staining for both Type IV collagen and laminin. Lymphatic capillaries, in contrast, uniformly lacked immunoreactivity with antibodies to these basement membrane components. These lymphatic capillaries, which were indistinguishable from blood vessel capillaries in both size (cross-sectional area) and shape (vessel eccentricity), were confirmed as lymphatics by dye injection studies. Our immunohistological technique detected 7-10 times more blood vessels than hematoxylin and eosin staining. Both benign and vessels than hematoxylin and eosin staining. Both benign and malignant tumors of blood vessel endothelium including two capillary hemangiomas and two angiosarcomas demonstrated extracellular linear staining for both Type IV collagen and laminin, whereas two lymphangiomas and two lymphangiectasias were negative. This method then provides a sensitive technique for detecting blood vessel capillaries in tissue sections and a reliable means of distinguishing blood vessel capillaries from lymphatic capillaries. This method may also aid in the identification of tumors whose origin is blood vessel endothelium.

Acute lymphocytic leukemia with prominent azurophilic granulation and punctate acidic nonspecific esterase and phosphatase activity.

Cytochemical, ultrastructural, and terminal deoxynucleotidyl transferase determinations in three cases of acute lymphocytic leukemia with azurophilic granules and punctate alpha-naphthyl acetate esterase (ANAE), alpha-naphthyl butyrate esterase (ANBE), and acid phosphatase (AP) activities further described a cytochemical and morphologic variant of acute lymphocytic leukemia. The ANAE, ANBE, and AP activities appeared specially localized within cytoplasmic granules. Electron microscopy substantiated a prominence of membrane-bound dense-core cytoplasmic granules. The variegated appearance of these dense-core granules and the cytochemical profile suggest that the aberrant granules are lysosomal in nature. Both the prominent cytoplasmic granules and the older age distribution led to early misdiagnosis of myelocytic leukemia. The distinctive cytochemical/morphologic profile and the ease of misdiagnosis suggest an important morphologic variant of acute lymphocytic leukemia.

Changes in collagen types during the healing of rabbit tooth extraction wounds.

Three alpha chains of type V collagen--alpha 1 (V), alpha 2 (V), and alpha 3 (V)--were initially demonstrated together with the expected collagen types I and III in the pepsin-soluble fraction of both normal mandibular bone and tooth extraction wound tissues of rabbits, as analyzed by sodium dodecyl sulfate-gel electrophoresis. The total collagen content of each extraction wound, as determined by the hydroxyproline assay, was observed to increase continuously from day 5 through day 17 and then leveled off or decreased. The ratio of type V to type I collagen was significantly higher in the initial stage of wound healing and decreased sharply down to the level of mandibular bone by day 5. The ratio of type III to type I collagen in the pepsin-soluble fraction increased and reached a maximum on day 5, whereas it was maximal on day 7 in the cyanogen bromide-soluble fraction, and thereafter decreased gradually in both fractions. The ratio for the pepsin-soluble fraction was, however, significantly higher than that for the cyanogen bromide-soluble fraction in the early stage of wound healing.

Inhibition of wound contraction with locally injected lathyrogenic drugs.

BACKGROUND: Previous studies using systematically administered lathyrogens to inhibit wound contractures have produced inconsistent results. The purpose of this study was to investigate the effects of lathyrogenic drugs on wound contraction when injected locally. METHODS: Two symmetrical full-thickness wounds were made on the dorsum of either side of hairless (hr/hr) mice; thus, each animal served as its own control. Animals were divided into groups receiving daily local injections of beta-aminopropionitrile or D-penicillamine, or both beta-aminopropionitrile and D-penicillamine and normal saline vehicle (control side) for 5 or 10 days. The rate of contraction was determined by serial measurements of the surface area of each wound during the treatment period. At the end of the treatment period, the wounds were excised en bloc with the chest wall and prepared for blinded histological analysis. Granulation tissue thickness, number of fibroblasts in granulation tissue per unit area, number of inflammatory cells (neutrophils, lymphocytes, macrophages and mast cells) in subjacent muscle per unit area, and collagen deposition in subjacent muscle were determined. RESULTS: Wound contraction, granulation tissue thickness, and collagen deposition in subjacent muscle were decreased only in wounds treated with beta-aminopropionitrile plus D-penicillamine. Collagen deposition in subjacent muscle was also decreased in wounds treated with D-penicillamine alone. Neither drug alone nor the combination affected the number of inflammatory cells in subjacent muscle. Body weight was not affected by the experimental procedures. CONCLUSIONS: The combination of beta-aminopropionitrile and D-penicillamine is potentially useful for inhibiting contracture formation when injected locally.

MRI of arachnoid granulations within the dural sinuses using a FLAIR pulse sequence.

The purpose of the study was to assess the signal intensities of arachnoid granulations within the dural sinuses using the FLAIR sequence for differentiation of space-occupying lesions in and adjacent to the dural sinuses. We retrospectively reviewed MR images of the brain of 1118 consecutive subjects, ranging in age from 0 to 93 years (mean 57.2 years). Nodules within the dural sinuses with signal intensities similar to that of cerebrospinal fluid (CSF) on both T1 and T2 weighted images were defined as arachnoid granulations. The location, signal intensity on T1 weighted spin echo (SE), T2 weighted fast SE and FLAIR images, the impression on the inner table of the skull, and the size of the lesion were assessed. 112 subjects (10.0%), age range 4-89 years old (mean 58.9 years), were found to have 134 arachnoid granulations. The commonest location was the transverse sinus, with 115 granulations (85.8%). The prevalence of the granulations showed a peak in the sixth decade of age. All granulations were isointense relative to CSF on T2 weighted images and almost all lesions were isointense relative to CSF on T1 weighted images. On FLAIR images, 90.3% of the granulations were isointense relative to CSF and the other 9.7% granulations were slightly hyperintense compared with the CSF. 21 (15.7%) subjects showed impressions on the inner table; one case involved the outer table. In conclusion, arachnoid granulations were isointense or slightly hyperintense relative to CSF on FLAIR. FLAIR images are helpful in differentiating arachnoid granulations from other dural sinus lesions or skull lesions which have an intensity similar to that of CSF on T1 weighted and T2 weighted images.

Healing of the oral mucosa with the use of collagen artificial skin.

Wounds were prepared in the oral cavity of 15 rabbits and five dogs, and an enzyme-solubilized calfskin collagen was placed over the surgery sites on one side. The contralateral sides acted as controls. Results indicated that the membrane was biologically acceptable to the oral mucosa of rabbits and dogs. Th collagen did not cause any adverse reaction and may have been responsible for the clinical impression of slightly more rapid healing of the gingivae in dogs. Clinical implications of this material's utilization produce some exciting ideas for future research.

A clinical evaluation of Proplast as a periodontal implant material.

Five patients received a Proplast implant in combination two- and three-wall osseous defects. In four of the cases the implant material was removed within 6 weeks due to failure to maintain primary closure over the Proplast and subsequent inflammation. One implant remained in place for 6 months with no apparent visual signs of inflammation. However, an 8 mm pocket remained, the area was reentered, and histologic sections made. The histologic sections revealed Proplast intermixed with bone, and the presence of foreign body giant cells.

Morphometric studies on wound healing after systemic administration of adriamycin and local application of fibrin sealant. Application of a new wound healing model using spongiosa implants.

For investigations on the development of regenerative granulation tissue in wound healing a new model using bone spongiosa ("Kieler Spongiosa") implants is presented. Particular attention was devoted to developing a model which permits studies on wound healing without disturbance by foreign body reaction and infections. Two test groups of rats received four blocks of "Kieler Spongiosa" each in a symmetrical fashion in a paramedian region underneath the dorsal skin. The spongiosa blocks had previously been treated with glutaraldehyde to achieve cross-linkage of the collagenous structures of the surfaces of the spongiosa trabeculae. After one week (group 1) and two weeks (group 2) the animals were sacrificed. The spongiosa blocks were removed, fixed and evaluated in layered serial sections after decalcification. Two blocks which had been removed randomly from the back and front served for morphometric determination of the total volume of bony substance and the developed granulation tissue. Moreover, the cellular composition of the granulation tissue was morphometrically examined with regard to its content of capillaries, granulation tissue cells and inflammatory cells. The two other blocks were examined for DNA and hydroxyproline content of granulation tissue. Comparison of the two experimental groups yielded marked differences in spongiosa space infiltrated by granulation tissue and its composition. Our model was used to assess the influence of systemic administration of adriamycin and/or local application of a fibrin sealant system on granulation tissue formation and its morphologic structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Vanadate ingestion increases the gain in wound breaking strength and leads to better organized collagen fibers in rats during healing.

Repair of incision wounds closed by suturing is evaluated by the progressive gain in wound breaking strength. Previously the closure of open wounds in rats ingesting vanadate, an inhibitor of tyrosine phosphate phosphatases, was shown to occur with deposition of more uniformly organized collagen fiber bundles. The hypothesis of this study was that deposition of more uniformly organized collagen fibers would enhance the gain in wound breaking strength of incisional wounds. Six adult rats received vanadate-supplemented saline drinking water for 1 week before placement of two 6-cm, parallel, suture-closed wounds on their backs. Six control rats received identical wounds and were given saline drinking water. The drinking water regimen was continued for 1 week after wounding, and then wound strength was tested with a tensiometer and tissue samples were obtained for histologic evaluation. Wound breaking strength doubled in vanadate-treated rats compared with controls. Bright-field and polarized light microscopy showed that the connective tissue matrix of granulation tissue from control rats was oriented perpendicular to the surface of the skin. In contrast, the connective tissue matrix of granulation tissue from vanadate-treated rats was oriented parallel to the skin surface. The gap in granulation tissue between the edges of the wounds in the vanadate-treated rats was greater than that in controls. Electron microscopy showed that wounds in the vanadate-treated contained uniform collagen fibers that were 20 percent greater in diameter and more evenly spaced than they were in controls. It is proposed that these changes in the organization of collagen fibers within incisional wounds were responsible for the increased wound breaking strength observed in rats ingesting vanadate.

Osteogenic potential of autogenic demineralized dentin implanted in bony defects in dogs.

The bone morphogenetic properties of implants of autogenic demineralized dentin were evaluated. The dentin matrix was implanted as small pieces and as thin slices in experimental mandibular osseous defects in dogs. The dentin implants were obtained from mandibular incisor teeth from the same dogs used in the experiment. Experimental interradicular osseous defects were surgically created in the mandibular premolars areas. 2 of the 3 defects were filled with either pieces or slices of prepared dentin. The 3rd defect served as an unfilled control. The results indicate that all demineralized autogenic dentin implants induce bone formation. There was an increase in the osteogenic capacity of the implant when the samples were used as thin slices. The slices of dentin matrix give no evidence of resorption and were readily incorporated into the new bone deposited. The end product was represented by a trabecular bone joined to the dentin matrix slices. In the case of the small piece samples, the specimens were readily resorbed and replaced by new deposits of cancelous bone. The osteogenic capacity of the small piece samples of the dentin matrix is less efficient comparable to the thin slice samples of the same implant material.

The mechanics of wound healing.

This paper discusses the factors which affect the healing of wounds at the tissue and organ levels. It covers some of the problems which complicate the sequence of healing and considers the mechanisms involved in regeneration and repair of tissues. The factors associated with the stimulus and sequence of healing and their interactions are also reviewed.

Arachnoid granulations on high-resolution MR images and diffusion-weighted MR images: normal appearance and frequency.

Arachnoid granulations (AGs), protrusions into the cerebral venous sinus lumen, have been reported on cerebral venography, contrast enhanced CT, and conventional MR imaging. Although thin-sliced high-resolution MR images and diffusion-weighted images are frequently obtained, there have been no detailed reports concerning AGs on these images. In this study, the frequency and positional distribution of AGs in the transverse sinus was investigated on thin-sliced high-resolution MR images, and their appearance on diffusion-weighted MR images was evaluated. At least one AG was found in 107 of 151 subjects (70.9%). No statistically significant differences were noticed between males and females or between the right and left sides. No significant correlations between age and size or between age and the number of AGs were noted. On diffusion-weighted images, all AGs showed iso-intensity to normal brain tissue, which was higher than the reported signal intensity of arachnoid cyst and lower than that of epidermoids. In conclusion, AGs are normal structures that are frequently found in the cerebral venous sinuses on high-resolution MR images. Knowledge regarding their frequency and normal appearance would be helpful to avoid confusion between pathological processes and AGs. It is also important to know that AGs are frequently found even in the younger population.

Myofibroblasts in cotton-induced granulation tissue and the bovine adrenal capsule: morphological aspects.

Ultrastructural studies of one week old cotton-induced granulation tissue revealed the presence of polymorphonuclear neutrophils (PMN), macrophages and mast cells, whilst the granulation tissue from two week old cotton implants contained fibroblasts, myofibroblasts and abundant collagen fibres. Similarly, the bovine adrenal capsule contained both fibroblasts and myofibroblasts. It is proposed that the bovine adrenal capsule and two week cotton-induced granulation tissue could be utilized as in-vitro models to study the mechanism(s) involved in myofibroblast contraction.

Surgical remodelling of the femoral trochlea: an experimental study.

Surgical deepening of the groove in the femoral trochlea is a technique commonly employed in the correction of patellar dislocation in dogs. In order to discover how this deep articular defect repairs the operation was studied experimentally in young goats. Observations were made on the appearance of the trochlea and the histologic changes that had taken place after approximately six, 12, and 40 weeks. The abraded groove became filled with fibrocartilage with a relatively smooth surface and it articulated freely with the patella. The majority of the replacement tissues arose by differentiation of the granulation tissue which initially filled the groove, but there appeared to have been some contribution made by the hyaline cartilage at the margins of the groove.

Toxic effects of dental amalgam implants. Optical histological and histochemical observations.

Dental amalgam and porcelain control discs were implanted in the subcutaneous tissue of rats. Amalgam implants exerted a toxic effect caused by release of metal ions which was characterized by prolonged inflammation, delayed granulation and disordered collagen formation. Dental porcelain was found to be a suitable biocompatible control which provided a bulk similar to that of dental amalgam but induced only an uncomplicated granulation response.

The effect of dextrin-rhEGF on the healing of full-thickness, excisional wounds in the (db/db) diabetic mouse.

Chronic wounds, such as ulceration of the lower limb, represent a significant clinical challenge in today's ageing society. With the aim of identifying improved therapeutics, we have previously described a bioresponsive, dextrin-recombinant human epidermal growth factor conjugate (dextrin-rhEGF), that (i) protects rhEGF against proteolytic degradation by human chronic wound fluid; and (ii) mediates rhEGF release by α-amylase, capable of stimulating increased proliferation/migration in normal dermal and chronic wound fibroblasts; and keratinocytes, in vitro. The aim of this study was to extend these findings, by investigating the effects of dextrin-rhEGF on wound healing in the (db/db) diabetic mouse, a widely used in vivo model of delayed wound healing. Standardised, full-thickness excisional wounds, created in the dorsal flank skin, were treated topically with succinoylated dextrin (50 µg/mL), rhEGF (10 µg/mL) or dextrin-rhEGF (1 or 10 µg/mL). Treatments were applied immediately after injury and subsequently on post-wounding, days 3 and 8. Wound healing was assessed macroscopically, in terms of initiation of neo-dermal tissue deposition and wound closure (including wound contraction and re-epithelialisation), over a 16 day period. Wound healing was assessed histologically, in terms of granulation tissue formation/maturity; cranio-caudal wound contraction and wound angiogenesis (CD31 immuno-staining), using tissues harvested at day 16. Blood samples were also analysed for α-amylase and rhEGF concentrations. In this established impaired wound healing model, the topically-applied dextrin-rhEGF significantly accelerated wound closure and neo-dermal tissue formation at the macroscopic level; and significantly increased granulation tissue deposition and angiogenesis at the histological level (p<0.05), relative to untreated, succinoylated dextrin and rhEGF alone controls. Overall, these findings support the further development of bioresponsive polymer conjugates, for tissue repair.