[Mixed reality technology in fibula flap preparation clinical teaching application].

Objective: To explore the effect of the application of mixed reality (MR) technology in clinical teaching of fibular flap preparation. Methods: Twenty residents from the Department of Oral and Maxillofacial Surgery in School of Stomatology, the Fourth Military Medical University in 2018 and 2019 participated in the present study. They were randomly divided into two groups according to the method of random drawing. The teaching content of the two groups was fibular flap preparation. The MR group was taught by using the new teaching mode which was mainly based on MR, while the conventional teaching group was educated by conventional teaching method. At the end of the training, the theoretical knowledge and operational skills of the residents were statistically analyzed to evaluate the learning effect. Questionnaire survey was also conducted. Each item in the questionnaire was scored between 0 and 5, representing poor to excellent. Results: The theoretical scores of MR group (91.4±4.4) were higher than that of the conventional teaching group (83.3±3.2) (P<0.01). The durations of preoperative marking and simulated osteotomy in MR group [(5.7±1.2) and (20.9±2.28) min, respectively] were shorter than those in the conventional teaching group [(7.2±1.7) and (26.1±3.6) min, respectively] (P<0.05). The results of the questionnaire showed that MR group had a significant improvement in the scores of classroom atmosphere, satisfaction, three-dimensional construction, theoretical knowledge and problem-solving ability (P<0.01). However, there was no statistically significant difference in scores of learning concentration between the two groups (P>0.05). Conclusions: The application of MR technology achieved a better teaching effect, which could help residents to deeply understand the methods of fibular flap preparation, and showed a broad application prospect.

Lipopolysaccharide induces paired immunoglobulin-like receptor B (PirB) expression, synaptic alteration, and learning-memory deficit in rats.

Some typical immune proteins are expressed in the nervous system, among which the paired-immunoglobulin-like receptor B (PirB) is a receptor for major histocompatibility complex class I antigen (MHC-I), but may play a physiological role in the brain for neuronal circuitry stability by inhibiting synaptic plasticity. Chronic neuroinflammation is common to many neurodegenerative diseases and is often associated with neuronal/synaptic damage and dysfunction. Here we examined the expression of PirB in the rat brain following intracerebral application of lipopolysaccharide (LPS), which has been shown to induce proinflammatory changes and cognitive deficits in rodents. One month after unilateral intrahippocampal LPS injection (10 µg in 4 µl phosphate-buffered saline, PBS), increased protein levels and immunoreactivity of PirB were detected in the ipsilateral hippocampal formation and cortex of the experimental group relative to vehicle (PBS) control. The increased PirB labeling was localized to astrocytes and neurons. Reduced synaptophysin protein levels and immunoreactivity were also found in the ipsilateral hippocampal formation and cortex in LPS-treated rats relative to controls. Morris water maze tests indicated that hippocampus-dependent spatial learning and memory were impaired in LPS-treated animals. Our findings add new experimental data for an upregulation of immune proteins in neuronal and glial cells in the brain in a model of endotoxin-induced neuroinflammation, synaptic alteration, and cognitive decline. The results suggest that PirB modulation may be involved in the pathological process under neurodegenerative conditions.

Application of nerve growth factor by gel increases formation of bone in mandibular distraction osteogenesis in rabbits.

The long period of bony consolidation is a concern in mandibular distraction osteogenesis (DO). We have previously shown that repeated local injections of human nerve growth factor beta (NGFß) can appreciably improve bony consolidation in a rabbit model of DO. The present study was designed to test the effect of a single injection of human NGFß delivered by collagen/nano-hydroxyapatite/kappa-carrageenan gels to sites of new bony formation in DO. Rabbits underwent mandibular DO at a rate of 0.75 mm/12h for 6 days. At the end of the distraction period, the following injections were given percutaneously into the callus (n=6 in each of the four groups): human NGFß in the gel; human NGFß in saline; the gels alone; and saline alone. Fourteen days after the end of distraction, mechanical testing, histological and histomorphometric variables of the new bone were evaluated. Histologically, the NGFß group had more advanced consolidation than the other three groups. Both maximal load and bone volume/total volume in this group were significantly higher than in the other three (P<0.05). In conclusion, the delivery of human NGFß in the gels results in better acceleration of new bone formation than when it is given in saline, and may be a possible way to shorten the duration of craniofacial DO.

Diagnosis and surgical treatment of carotid body tumors: 25 years' experience in China.

Carotid body tumors (CBT) are rare neoplasms arising from the small chemoreceptor organ in the adventitia of the common carotid bifurcation. A retrospective survey was conducted in 33 patients, treated by curative resection of the neoplasm, from 1980 to 2005, to investigate clinical features, preoperative treatment and surgical approach, and determine the optimum management for CBT. The demographic characteristics, clinical features, surgical approach and complications were documented and analyzed. Accurate diagnosis and effective preoperative training were associated with a good surgical outcome. Carotid arteriography accurately diagnoses and evaluates the brain's collateral circulation in the circle of Willis. Ultrasonography is useful. Carotid blood flow obstruction (Matas' training) is effective. Complete excision of the carotid system without a vascular replacement is possible only after reliable Matas' training and objective observation of the establishment of circulation in the circle of Willis. Correct treatment of the internal and common carotid artery is important to reduce postoperative complications. The continuity of the common and internal carotid artery should be retained if possible, and carotid artery repair is recommended. Minor complications occurred in five (15%) patients and one patient died from a cause not related to the CBT at follow-up.

Effects of estrogen and raloxifene on neuroglia number and morphology in the hippocampus of aged female mice.

Hormone replacement therapy with the gonadal steroid estrogen or synthetic agents such as raloxifene, a selective estrogen receptor modulator, may affect cellular function in brains of postmenopausal women. In vitro studies suggest that 17beta estradiol and raloxifene can alter the microglial and astrocyte expression of immuno-neuronal modulators, such as cytokines, complement factors, chemokines, and other molecules involved in neuroinflammation and neurodegeneration. To directly test whether exogenous 17beta estradiol and raloxifene affect the number of glial cells in brain, C57BL/6NIA female mice aged 20-24 months received bilateral ovariectomy followed by s.c. placement of a 60-day release pellet containing 17beta estradiol (1.7 mg), raloxifene (10 mg), or placebo (cholesterol). After 60 days, numbers of microglia and astrocytes were quantified in dentate gyrus and CA1 regions of the hippocampal formation using immunocytochemistry and design-based stereology. The results show that long-term 17beta estradiol treatment in aged female mice significantly lowered the numbers of astrocytes and microglial cells in dentate gyrus and CA1 regions compared with placebo. After long-term treatment with raloxifene, a similar reduction was observed in numbers of astrocytes and microglial cells in the hippocampal formation. These findings indicate that estrogen and selective estrogen receptor modulators can influence glial-mediated inflammatory pathways and possibly protect against age- and disease-related neuropathology.

[Neocartilage of predetermined shapes].

OBJECTIVE: To study chondrogenesis of calcium alginate-chondrocytes predetermined shapes. METHODS: Chondrocytes isolated from ears of rabbit by type II collagenase digestion, and then were mixed with 1.5% solidium alginate solution. The suspension was gelled to create three spatial shapes as triangle, circle and quadrilateral by immersed into 2.5% CaCl2 for 90 minutes, and then was implanted into the subcutaneous pocket on the dorsum of the rabbit. Samples were harvested at 6 and 12 weeks after implantation. RESULTS: Gross examination of excised specimens at 6 and 12 weeks after implantation revealed the presence of new cartilage of approximately the same dimensions as the original construct. Histologic evaluation using hematoxylin and eosin stains confirmed the presence of cartilage nodules at 6 weeks after implantation. After 12 weeks, mature cartilage was observed and histologic analysis confirmed the presence of well formed cartilaginous matrix. CONCLUSION: Predetermined shapes neocartilage can be regenerated using calcium alginate as a carrier of chondrocytes in the bodies of immune animals.

[Influence of lead on activity of nitric oxide synthase in neurons and vessel smooth muscle of small intestine in rats].

The beta-NADPH histochemical method was used to study the effect of lead on activity of nitric oxide synthase(NOS) in neurons and vessel smooth muscles of intestinal wall in rats. The results showed that the number of NOS positive neurons and fibers was decreased and degenerative changes of some NOS positive neurons were found after the lead acetate intraperitoneal injection. The activity of NOS in the vessel smooth muscles was reduced. It suggests that lead colic may be induced by reduction of NO in the neurons which innervate the gut smooth muscles.

A study of injectable tissue-engineered autologous cartilage.

OBJECTIVE: To test the effectiveness of the new techniques of tissue-engineered cartilage. METHODS: Chondrocytes were harvested through type II collagenase digestion from the auricle of New Zealand rabbits. The cells were mixed with alginate to generate chondrocytes/alginate composites with final cellular density of 50 x 10(6) per mL. Calcium chloride was used as the cross-linking agent to gel the aqueous alginate solution. The chondrocytes/alginate composites were injected into the dorsal subcutaneous tissue of New Zealand rabbits through autologous cells grafts. The specimens were observed during cartilage formation at 4, 8, and 12 weeks after injection. RESULTS: Prior to harvesting, chondrocytes/alginate composites were easily visualized under the dorsal skin of animals. The appearance of experimental specimens was similar to that of native cartilage in gross morphology. Using a standard hematoxylin and eosin stain, the histologic features of all experimental specimens demonstrated new cartilage formation. With a Masson's trichrome and safranin O stain, the presence of collagen and glycosaminoglycan (GAG) was observed at 8 and 12 weeks. CONCLUSION: This study demonstrated that polymerization of alginate hydrogel can be controlled to allow injection of chondrocytes that produce new autologous cartilage at subcutaneous dorsal site of rabbits. Injectable tissue-engineered autologous cartilage is promising for potential use in oral and maxillofacial surgery.

Risk of linear growth retardation during the first two years of life: a new approach.

OBJECTIVE: Estimate the risk of linear growth retardation during the first two years of life as a result of household social vulnerability. SETTING: Families who participated in the National Supplementary Feeding Program in the Health Units of the metropolitan area of the city of São Paulo, Brazil. SUBJECTS: Four hundred and thirty-one index-babies, weighing more than 2500 grams and who had at least one young sibling under the age of five who participated in the Program for a minimum of two years. DESIGN: The index-babies were divided into two cohorts: 74.9% coming from 'non-stunted families' (those with normal height siblings) and 25.1% from 'stunted families' (those with stunted siblings). The study design allowed the observation of growth patterns over a period of time and over a childhood growth range. It also allowed the estimation of the stunting and the recovery probabilities at each moment, not only within a given age range. The transition probabilities between 'stunted' and 'non-stunted' index-babies were estimated. The relative risk ratio (RR) was also calculated. RESULTS: The prevalence of stunting in the index-babies at 12 and 24 months of age was significantly greater in 'stunted families' (P < 0.001). Probabilities of becoming stunted began to differ from the fourth month on (confidence intervals non-superposed), and were higher for index-babies from 'stunted families'. The recovery probability of a stunted child was smaller in the 'stunted families' cohort after the 12th month of age. From the third month on, the (RR) was always above 1.5. CONCLUSION: The family context exposes children to failure in growth in the first two years of life when there are already stunted children in the household.

Local injection of kainic acid causes widespread degeneration of NADPH-d neurons and induction of NADPH-d in neurons, endothelial cells and reactive astrocytes.

Nitric oxide (NO), a diffusible gas, is a messenger molecule that mediates vascular dilatation and neural transmission. The enzyme nitric oxide synthase (NOS) present in neurons is activated by Ca2+ influx associated with activation of glutamate receptors. Cultured cortical neurons containing NOS are selectively vulnerable to injury by kainic acid (KA). However, the relationship between NOS neurons and excitotoxicity under in vivo conditions is not entirely clear. In the present study, we examined the time course and spatial distribution of changes in NOS neurons caused by an intracortical microinjection of KA in adult rats. NADPH-diaphorase (NADPH-d) histochemistry was used as a marker for NOS and the neuronal changes were correlated with changes in glial cells and endothelial cells. We demonstrated a rapid loss of NADPH-d neurons in the lesion center and degeneration of NADPH-d neurons and nerve terminals throughout ipsilateral cortex and hippocampus; the striatal neurons appeared to be unaffected. Subsequent to cortical neuronal degeneration, new NADPH-d activity appeared in proliferative reactive astrocytes and in endothelial cells at lesion periphery, and in neuronal groups at lesion periphery, in ipsilateral entorhinal cortex and bilateral hippocampus. These findings indicate that neurons expressing NADPH-d in cerebral cortex and hippocampus are selectively vulnerable to KA toxicity in vivo. The subsequent induction of NOS in neural and non-neural cells may be regarded as an adaptive response to the kainate-induced brain lesion.

Kainate-induced brain lesion: similar local and remote histopathological and molecular changes as in ischemic brain infarct.

Cerebral ischemia/hypoxia induces histopathological changes characterized by nuclear and cytoplasmic condensation and sustained c-fos expression. The ischemic changes are thought to be initiated by excessive glutamate released by the ischemic neurons. However, no comparative study has been made between the pathological and molecular changes caused by local injection of excitotoxin and by ischemia. In the present study, we investigated the histopathological changes in rat brains induced by an intracerebral microinjection of kainic acid, a potent analogue of glutamate using two newly available markers for ischemic neurons: Fos immunohistochemistry and EA 50 stain. The rats were sacrificed at intervals from 1 hour (h) to 28 days. We demonstrated that the neurons at the site of injection developed changes typical of ischemia 1 h post-lesion: nuclear and cytoplasmic condensation, strong Fos immunoreactivity and positive EA 50 stain. By 1 day, the neurons underwent necrosis and an infarct-like picture was produced. The neuronal degeneration rapidly spread to the bilateral neocortex, CA3 and CA4 regions of hippocampus, piriform gyrus, amygdala and cerebellar Purkinje cells. After 3 days, there was neovascularization and macrophage production in the lesion center and astrocytic proliferation at the lesion periphery. The CA1 of hippocampus showed delayed neuronal necrosis typical of ischemia. Thus, intracerebral microinjection of KA induces similar histopathological and molecular changes as those occurring in brain infarct and is a simple and reliable model for studying changes related to focal brain infarct.

[Anemia and malnutrition in children at public schools in Osasco, São Paulo, Brazil]. / Anemia e desnutrição em escolares da rede pública do município de Osasco, São Paulo, Brasil.

The authors studied a sample of students entering the first grade in the Osasco public school system in order to determine both the prevalence of anemia and nutritional status. Osasco is part of the Greater S o Paulo Metropolitan Area. Diagnosis of anemia was made through the hemoglobin concentration of blood from digital puncture. World Health Organization (WHO) levels were used to define anemia. Nutritional Status assessment. was made through weight/age and height/age indices, using Z score distribution and the National Center for Health Statistics (NCHS) reference levels. Prevalence of anemia was 51%. Prevalence levels varied according to the schools' geographic location: 56.9% in peripheral neighborhoods and 41.7% in central areas. Children with illiterate parents had a higher prevalence of this condition. Risk of anemia was higher for children who were over eight years of age when entering the first grade. Acute malnutrition was not found. Prevalence was higher than expected and points to the urgent need to establish an anemia control program for schoolchildren in this population.

[Linear growth retardation and classroom performance of children from the city of Osasco, São Paulo, Brazil]. / Retardo do crescimento físico e aproveitamento escolar em crianças do Município de Osasco, área Metropolitana de São Paulo, Brasil.

The objective of the present study was to investigate the significance of linear childhood growth retardation in relation to classroom performance. It began with a Height Census carried out in the 1989 school year, involving children attending the first grade of all public and private schools in Osasco (Greater S o Paulo Metropolitan Area, Brazil), which identified the presence of growth retardation. Using a prospective study, classroom performance was evaluated throughout the school year in 170 children entering school and characterized by the height-for-age indice below -2 z scores (NCHS/OMS reference population) and in 205 children entering school and characterized by height-for-age above -1 z score. Classroom performance of stunted school children was lower than that of students without growth retardation. The study indicated that increased risk of school failure of those students remained the same, even after adjustment for possible confounding variables (present nutritional status and socioeconomic variables).

[The height census of first grade schoolchildren: data quality and cost analysis in two Brazilian municipalities]. / A coleta da altura de alunos ingressantes nas escolas de primeiro grau em um sistema de vigilância nutricional: qualidade dos dados e análise de custo em dois municípios brasileiros.

The present study describes a first attempt in Brazil to establish a nutrition surveillance system based on the systematic collection of the height of children entering the first grade of primary school. The strategy used recognized the School District as the nuclear institution to operate the system. A quality control system showed that trained people were able to collect anthropometric data with margin of error compatible with the purposes of the system. Costs were low, around 30 cents US per child examined, and they can be further reduced since the system is operated in large scale.

Fragment A-B of tetanus toxin does not block neuromuscular transmission in the goldfish.

While 4 micrograms of Fragment A-B of tetanus toxin (which lacks the binding site for nervous tissue) causes flaccid paralysis and death in mice, 26 micrograms has no toxic effect in goldfish. Antibodies to either A-B or to fragment C (which contains the binding site) block the paralytic effect of whole toxin in goldfish. It is concluded that binding is necessary for the neuromuscular blocking action of the toxin in goldfish.

Isolation, purification, and characterization of fragment B, the NH2-terminal half of the heavy chain of tetanus toxin.

Fragment B, the N-terminal half of the heavy chain, an important domain of the tetanus neurotoxin molecule, was isolated for the first time. Tetanus toxin (composed of three domains, A, B, and C) was prepared from culture filtrates. Fragment A-B, derived from the toxin treated mildly with papain, was used for the isolation of fragment B. Fragment A-B obtained was dissociated into fragments A and B by reduction with 100 mM dithiothreitol and treatment with 2 M urea. Fragment B was separated from fragment A by ion-exchange column chromatography on a Mono Q column equilibrated with 20 mM Tris hydrochloride buffer (pH 7.6), containing 1 mM dithiothreitol and 2 M urea, in a fast-protein liquid chromatography system by elution with a linear gradient of 0 to 0.5 M NaCl. Fragment B was obtained in two forms having molecular weights of 48,000 +/- 2,000, which were indistinguishable by sodium dodecyl sulfate-gel electrophoresis or antigenic specificity, but distinguishable on polyacrylamide gel electrophoresis without sodium dodecyl sulfate and on isoelectric focusing (pI 6.7 and 7.3). The recovery of fragment B was 50 to 72% of that of fragment A-B on a molar basis. Purified fragment B was not toxic to mice on intravenous or intramuscular injection at doses of up to 100 micrograms, but was found to form channels (ca. 2.3 pS) in a lipid bilayer membrane by a patch clamp technique. The role of domain B of the tetanus toxin molecule in the mechanism of action of the toxin is discussed.

[Assessment of the impact of nutritional rehabilitation programs on preschool children: test of a methodology]. / Medindo o impacto de programas de recuperação nutricional de pré-escolares: teste de uma metodologia.

Two different approaches to the evaluation of the impact of food supplementation given to malnourished children are assessed on the basis of the experience of a program undertaken in the county of Diadema, in the metropolitan area of S. Paulo, Brazil. The first approach--a traditional one--is based on the proportion of children that at the end of one year's participation in the program present no weight deficit (weight for age more than 90% of the expected value). The second approach--proposed in the article--takes into account only the rate of growth and accepts weight increments superior to those expected among well-nourished children as favorable. The advantages of this second approach are fully demonstrated.

Isolation and purification by high performance liquid chromatography of a tetanus toxin fragment (fragment [A-B]) derived from mildly papain-treated toxin.

Fragment [A-B] of tetanus toxin was highly purified by combination of gel permeation chromatography, adsorption chromatography in an HPLC and immunoadsorption chromatography using anti-Fragment [C] as a ligand. The purified Fragment [A-B] (200 micrograms) elicited a peculiar toxicity, 'hypoactivity' or 'weakness', and killed the mice in ca. 73 hr and 88 hr when it was injected i.v. and i.m., respectively. However, contamination by the whole toxin was not detectable, in the purified fragment preparation, when up to 600 micrograms was tested by the mouse toxicity assay.