Malignant hemispheric infarction of the middle cerebral artery. Diagnostic considerations and treatment options. / Infarto hemisférico maligno de la arteria cerebral media. Consideraciones diagnósticas y opciones terapéuticas.

INTRODUCTION: Malignant hemispheric infarction (MHI) is a specific and devastating type of ischemic stroke. It usually affects all or part of the territory of the middle cerebral artery although its effects may extend to other territories as well. Its clinical outcome is frequently catastrophic when only conventional medical treatment is applied. OBJECTIVE: The purpose of this review is to analyse the available scientific evidence on the treatment of this entity. DEVELOPMENT: MHI is associated with high morbidity and mortality. Its clinical characteristics are early neurological deterioration and severe hemispheric syndrome. Its hallmark is the development of space-occupying cerebral oedema between day 1 and day 3 after symptom onset. The mass effect causes displacement, distortion, and herniation of brain structures even when intracranial hypertension is initially absent. Until recently, MHI was thought to be fatal and untreatable because mortality rates with conventional medical treatment could exceed 80%. In this unfavourable context, decompressive hemicraniectomy has re-emerged as a therapeutic alternative for selected cases, with reported decreases in mortality ranging between 15% and 40%. CONCLUSIONS: In recent years, several randomised clinical trials have demonstrated the benefit of decompressive hemicraniectomy in patients with MHI. This treatment reduces mortality in addition to improving functional outcomes.

Normal long bone growth and development in type X collagen-null mice.

To investigate the role of type X collagen in skeletal development, we have generated type X collagen-null mice. Surprisingly, mice without type X collagen were viable and fertile and had no gross abnormalities in long bone growth or development. No differences were detected between the type X collagen-null mice and controls when growth plates of both newborn and 3-week old mice were examined by histology and by immunostaining for extracellular matrix components of bone including osteopontin, osteocalcin and type II collagen. Our results suggest that type X collagen is not required for long bone development. However, mice and humans with dominant acting type X collagen mutations have bone abnormalities, suggesting that only the presence of abnormal type X collagen can modify bone growth and development.

General care in the management of severe traumatic brain injury: Latin American consensus. / Cuidados generales en el manejo del traumatismo craneoencefálico grave: consenso latinoamericano.

Severe traumatic brain injury (sTBI) remains prevalent in the young adult population. Indeed, far from descending, the incidence of sTBI remains high. One of the key bases of treatment is to avoid, detect and correct secondary injuries of systemic origin, which aggravate the primary lesion. Much of this can be achieved by maintaining an adequate physiological microenvironment allowing recovery of the damaged brain tissue. General care measures are nonspecific actions designed to meet that objective. The available guidelines on the management of sTBI have not included the topics contemplated in this consensus. In this regard, a group of members of the Latin American Brain Injury Consortium (LABIC), involved in the different aspects of the acute management of sTBI (neurosurgeons, intensivists, anesthesiologists, neurologists, nurses and physiotherapists) were gathered. An exhaustive literature search was made of selected topics in the LILACS, PubMed, Embase, Scopus, Cochrane Controlled Register of Trials and Web of Science databases. To establish recommendations or suggestions with their respective strength or weakness, the GRADE methodology (Grading of Recommendations, Assessment, Development and Evaluation) was applied. Additionally, certain recommendations (included in complementary material) were not assessed by GRADE, because they constitute a set of therapeutic actions of effective compliance, in which it was not possible to apply the said methodology. Thirty-two recommendations were established, 16 strong and 16 weak, with their respective levels of evidence. This consensus attempts to standardize and establish basic general care measures in this particular patient population.

Phagocytosis of latex beads by a human gingival epithelial-like cell line in tissue culture.

Phatocytosis by a human gingival epithelial-like cell line in tissue culture was studied using latex beads as a marker. Electron microscopic and chemical analyses revealed that the cells ingested the beads in a quantitative and reproducible manner. This phagocytosis system is potentially useful for studying the effects of dental plaque on cell metabolism.

Scanning electron microscopic and radiographic correlation of articular surface and supporting bone of the mandibular condyle.

Specimens of mandibular condyle from human cadavers were employed for scanning electron microscopic and radiographic observations of the articulating surface and underlying bone. Smooth articular surface supported by smooth bone was most frequently observed. Craters and depressions in the articular surface were associated with resorption of underlying bone. Lateral radiographs proved to be of limited value in detecting defects of this type.

Human gingival fibroblast production of interferon.

Three human gingival fibroblast cell lines were used to determine whether they could be induced by a synthetic RNA and superinduced by metabolic inhibitors to produce interferon (IFN-beta). When established procedures were followed for human fetal or newborn skin fibroblast cell lines, the adult gingival fibroblasts produced comparable amounts of IFN-beta. It was shown that the superinducers alone would not cause an IFN-beta production response, and that the absence of serum in the production medium also inhibited the production of IFN-beta. The effect of IFN-beta on cell growth was carried out in T-flasks seeded with 10(5) HEp-2 cells. After one and two wk, the cells of triplicate control flasks and triplicate flasks containing various dilutions of the production media were enumerated to determine a cell multiplication inhibition (CMI) value. A correlation between the IFN-beta content and the CMI effect, however, was not obtained, and it was concluded that other CMI agents, possibly more potent than the IFN-beta, were being produced by the stimulated human gingival fibroblasts. Cell protein assays which gave a high ng/cell protein content correlated with TEM micrographs which showed clusters of complex lysosomes, primarily in cells cultured in the IFN-beta-containing nutrient. However, since commercial IFN-beta initiated no such lysosomal response, it was further concluded that the complex lysosomes were due to CMI agent(s) other than IFN-beta.

Microfilaments in human cementoblasts and periodontal fibroblasts.

An electron microscopic survey was carried out on the human periodontal ligament (PDL), including a part of the gingival connective tissue attached to extracted tooth roots (11 functioning premolars and 6 nonfunctioning third molars) in order to examine the characteristics of microfilaments (6 nm) in cementoblasts and PDL fibroblasts. Microfilaments which were grouped in bundles with semiperiodic dense nodes or in meshworks just beneath the cell membrane were seen predominantly in the cells characterized by their ultrastructurally immature appearance. These microfilaments were more commonly observed in third molar PDL than in premolar PDL and, in general, more conspicuous in cementoblasts than in fibroblasts. The significance of microfilaments in human PDL is discussed, particularly in relation to cell differentiation and morphogenesis.

Ultrastructural and morphometric analyses of human cementoblasts and periodontal fibroblasts.

In order to elucidate the cytological characteristics of human cementoblasts which distinguish them from periodontal fibroblasts, the periodontal ligament and gingival connective tissue attached to 37 extracted teeth from 27 patients (ages 10-67) were analyzed by electron microscopy coupled with a morphometric procedure. The cementoblasts largely consisted of either immature or resting types of collagen-producing cells (CPC), both of which were poor in the rough endoplasmic reticulum and Golgi complex; these organelles were well-developed in the relatively less common active cementoblasts. The cementoblasts consistently revealed a higher mean-volume-density per tissue unit than the fibroblasts and sometimes were grouped into clusters with the formation of junctional apparatuses. The relative volume of glycogen particles per cytoplasm was significantly higher in the cementoblasts, whereas the rough endoplasmic reticulum was higher in the fibroblasts. From the present study, it is suggested that the cementoblasts are functionally less active CPC than the periodontal fibroblasts.

Differential effect of TGF-beta 1 and PDGF on proliferation of periodontal ligament cells and gingival fibroblasts.

Regeneration of periodontal tissues requires orchestration of several cell types. Two cell types, gingival fibroblastic cells (gingival fibroblasts) and cells from the periodontal ligament (PDL cells), were studied to compare the effects of supplemental addition of TGF-beta 1 and PDGF on proliferation. Cells obtained from healthy donors were cultured in 10% FBS supplemented with either 10 ng/ml TGF-beta 1, 20 ng/ml PDGF, or both. Thymidine incorporation was measured after 24, 48, or 72 hours. Data from PDL (analyzed by ANOVA) showed the following relations: at 24 hours TGF beta 1/PDGF = PDGF > TGF-beta 1 = control; at 48 hours TGF beta 1/PDGF > TGF-beta 1 > PDGF > control; at 72 hours TGF beta 1/PDGF > TGF-beta 1 > PDGF = control. Gingival fibroblast cultures showed the following relations: at 24 and 48 hours TGF beta 1/PDGF = PDGF > TGF-beta 1 = control; at 72 hours, TGF beta 1/PDGF = PDGF > control with TGF beta 1 not different from control or factor combinations. Both TGF-beta 1 and TGF-beta 1/PDGF showed a significantly greater increase in proliferation of PDL cells than in gingival fibroblasts at 48 and 72 hours (Student t test P < 0.05). In contrast, PDGF stimulated proliferation of gingival fibroblasts was significantly greater than PDL cells at 72 hours (P < 0.05). Thus, supplementation of complete cultures (containing 10% FBS) with TGF-beta 1 alone or combined with PDGF stimulates proliferation of PDL cells to a significantly greater extent than proliferation of gingival fibroblasts.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuously infused calcium hydroxide: its influence on hard tissue repair.

To study the ability of calcium hydroxide to promote hard tissue repair, Alza Alzet Osmotic Pumps, implanted in Sprague-Dawley rats, were used to deliver either calcium hydroxide and glycerol, barium hydroxide and glycerol, tetracycline and glycerol, or glycerol only to a standardized round bur defect in a rat femur. The pumps infused one of the reagents into the defects continuously over a 4-wk experimental period. The effects of each reagent on the healing of the bony defects were compared by histological evaluation. The Alza Osmotic Pump proved to be an effective method to deliver an agent to an experimental site. Our preliminary findings from a limited sample size indicated that calcium hydroxide contributed to a more complete osseous repair than either barium hydroxide or tetracycline. Barium hydroxide with a sustained pH equivalent to calcium hydroxide showed no greater healing than the controls. Tetracycline results were also similar to controls.

An ultrastructural study of human epithelial rests of Malassez maintained in a differentiated state in vitro.

Healthy human periodontal ligaments (PDL), obtained from the extracted teeth (premolars and third molars), were cultivated for 1-35 days, using a multi-purposes culture chamber (MPCC) equipped with various transparent membranes. The resting state of the epithelial rests of Malassez (ERM), similar to their in vivo counterparts, appeared as small islands or strands with scant cytoplasm containing poorly developed organelles. This state was most effectively maintained in MPCC with a cellophane sheet. MPCC with a Sartorius membrane filter permitted proliferation and emigration of ERM. Proliferating ERM were characterized by more profiles of rough endoplasmic reticulum and free ribosomes, new formation of actin-containing microfilaments, less prominent tonofilaments and desmosomes and loss of gap junctions. Most of these ultrastructural changes are manifested in epithelial cells during wound healing. The emigrating ERM from PDL explants, as well as occasional proliferating ERM within explants, consisted of two cell types--outer basal-like cells, as described above, and inner tonofilament-rich prickle-like cells, suggesting a propensity for differentiation of ERM. The results show the possibility of controlling the growth and differentiation of ERM through the MPCC culture environment.

Bone matrix proteins in osteogenesis and remodelling in the neonatal rat mandible as studied by immunolocalization of osteopontin, bone sialoprotein, alpha 2HS-glycoprotein and alkaline phosphatase.

The neonatal rat mandible was used as a model to study bone formation, mineralization, quiescence, and resorption, using immunolocalization and a variety of tissue-processing techniques. Monospecific antibodies for osteopontin (OPN), bone sialoprotein (BSP), alkaline phosphatase (AP) and alpha 2HS-glycoprotein (alpha 2HS-GP) were used on fixed paraffin-embedded tissue, fixed frozen tissue and unfixed frozen tissue. Immunostaining was correlated with mineral content by two procedures, the von Kossa and the morin techniques. Morin fluorescence was used with secondary immunostaining to provide a way of closely correlating bone matrix proteins and matrix mineralization. Co-immunolocalization procedures were used to compare the sites of bone proteins in the matrix. AP was found earliest during osteogenic cell differentiation, appearing in the preosteoblasts, followed by OPN and BSP, which first appeared in osteoblasts. alpha 2HS-GP expression was not observed in cells. The results provide clear evidence for the presence of OPN in osteoid, while BSP and alpha 2HS-GP were confined to the mineralized matrix. Immunostaining of bone proteins is highly technique-dependent: immunolocalization investigations required several methods of approach to ensure adequate demonstration of these proteins in cells and matrix. The results support the contention that osteopontin is multifunctional in bone metabolism, and that alpha 2HS-GP, though produced in the liver, is abundant in bone matrix and may also have a function in bone metabolism.

Integrated processes responsible for soft tissue healing.

Wounded soft tissues undergo repair through a complex series of interrelated events that involve both physical and chemical activities. These processes are currently undergoing extensive investigation as efforts are directed toward achieving augmented and accelerated healing. Early wound-healing research focused on expanding traditional histologic descriptions of tissue healing by attempting to characterize the environment and biologic mediators responsible for healing. These initial studies successfully identified a number of agents and physiochemical factors present in healing wounds, but their precise roles and importance remain largely unknown. This review article summarizes the current literature on soft tissue healing. An effort has been made to correlate the activities of the major growth factors and cytokines with the individual reparative processes including the inflammatory response, hemostasis, fibroplasia, angiogenesis, and remodeling. Explanations and characteristics of growth factor function as well as brief descriptions of several major factors and their spectrum of activity are also provided.

Treatment of a patient with hereditary gingival fibromatosis: a case report.

A case of hereditary gingival fibromatosis is presented. Treatment consisted of apically positioned flap surgery and CO2 laser evaporation. Diagnostic and treatment issues are discussed.

Utilization of cadaver tissue for a scanning electron microscopic study of the insertion of the masseter muscle.

1. The generally poor state of soft tissue preservation that complicates observations by gross dissection and light microscopy posed no hindrance to scanning electron microscopic (SEM) studies of bone surface, because all of the soft tissues are chemically removed. 2. Specific and identifiable surface patterns representing locations of periosteal and fibrous muscle attachments can be readily observed in cadaver tissue with the SEM. 3. SEM observations confirmed earlier literature concerning the extent of periosteal and intraosseus attachments of the masseter muscle. The masseter muscle attached periosteally on the lateral surface of the mandible and along the inferior border. Just above the inferior border, a ridge of intraosseous attachment was noted. 4. The correlation of SEM observation of bone surface patterns with gross dissection and light microscopy demonstrated that SEM can be useful in determining the extent of muscle attachments in cadaver tissue even when the soft tissue is poorly preserved.

Immunolocalization of connexin 43 in the tooth germ of the neonatal rat.

Rabbit polyclonal antibodies to amino acids 346-360 of connexin 43, the 'heart' gap junction protein, were employed to immunolocalize connexin 43 gap junctions in the neonatal rat molar tooth germ. Connexin 43 appears early in the differentiation of both ectodermally derived and ectomesenchymally derived cells of the developing tooth. Connexin 43 immunoreactivity is present in the epithelial components of the enamel organ, including the area of the proximal and distal junctional complexes of the ameloblast layer, and the stratum intermedium, stellate reticulum and outer enamel epithelium. Secretory odontoblasts and developing alveolar bone also display a pattern of connexin 43 immunostaining. Both the epithelial and ectomesenchymally-derived components of the developing tooth acquire connexin 43 channels in a manner that correlates with cell differentiation. In addition, three regions can be defined by connexin 43 immunostaining: the epithelia of the enamel organ that are derived from the oral epithelium, the odontoblast layer derived from the ectomesenchyme, and the alveolar bone. The results suggest that connexin 43 may provide the mechanism for functional compartmentalization of the tissues associated with tooth formation. Compartmentalization suggested by connexin 43 expression could play important roles in the development and functions of these tissues.

Molecular analysis of rat dentin sialoprotein.

Dentin sialoprotein (DSP) is a noncollagenous protein originally isolated from rat dentin. Because it is made by odontoblasts that are actively synthesizing dentin. DSP may play an important role in dentinogenesis. We have isolated a full length DSP cDNA from a rat odontoblast/dental pulp cDNA library (Ritchie et al. [1994] J. Biol. Chem. 269:3698-3702) which codes for a 17 residue signal peptide and a 366 residue, 53 kDa mature protein. In situ hybridization revealed DSP mRNA expression by odontoblasts, but no other cells, in jaws from newborn rat. Northern analysis of various rat tissues demonstrated the presence of DSP transcripts in newborn tooth germs and 21 day old rat incisors. Moreover, multiple transcripts of 4.6 kb and 1.5 kb were found in these two tissues. To better understand the origin of these DSP mRNA multiple transcripts, we have isolated two rat genomic clones. Digestion of each clone with EcoRI followed by Southern analysis revealed that DSP cDNA hybridized to a 4 kb fragment in a lambda dash clone and to a 6 kb fragment in a cosmid clone. Since DSP cDNA hybridized to a 6 kb EcoRI fragment and a 4 kb EcoRI fragment obtained from a rat liver genomic cDNA digested with EcoRI, the multiple DSP mRNA transcripts are most likely derived from two related DSP genes which coexist in the rat genome.