Healing following reimplantation of teeth subjected to root planing and citric acid treatment

The aim of the present study was to examine the effect of citric acid treatment on periodontal healing around teeth which were extracted, root planed and then reimplanted. Maxillary incisors and mandibular incisors, premolars and molars of 5 monkeys were used. The teeth were divided into 3 experimental groups. In 1 group, the teeth were extracted and immediately reimplanted into their own sockets. In a 2nd group, the teeth were extracted, root planed to a level corresponding to 50-75% of the root length and then reimplanted. In the 3rd group, periodontal breakdown extending to 50-75% of the root length was first induced by placing orthodontic elastic ligatures around the teeth. They were then extracted and root planed and transplanted into the sockets of the contralateral, periodontally healthy teeth which had just been extracted. Half the number of the teeth of groups 2 and 3 were treated with citric acid before reimplantation or transplantation. The animals were sacrificed after 6 months of healing. The jaws were removed and histological specimens prepared for microscopic examination. With the exception of a limited coronal regrowth of new cementum in the apical part of the planed portion of a few roots, connective tissue attachment failed to reform on most root surfaces deprived of their periodontal ligament tissue. Healing was most frequently characterized by root resorption and ankylosis. These were the most predominant features of healing both on root surfaces which had been deprived of the ligament tissue by mechanical means or during a course of experimentally-induced periodontal disease, and occurred in citric acid as well as non-citric acid treated roots. The findings imply that the result of healing following tooth reimplantation or transplantation is determined by the type of cells that repopulate the wound area adjacent to the denuded root surface.     

The development of Purkinje fibres and ordinary myocytes in the bovine fetal heart

Summary A comparative ultrastructural study of bovine Purkinje fibres and ordinary myocytes during fetal development has been undertaken. Differences between the two cell types with respect to the intercalated disc, amount of myofibrils, arrangement of mitochondria, amount of glycogen and formation of T-tubules became apparent gradually. In all stages studied an abundance of intermediate filaments was typical for the Purkinje fibres. Myofibrillar M-bands developed at an earlier stage in Purkinje fibres than in ordinary myocytes. Myofilament-polyribosome complexes typical of adult cow Purkinje fibres were not observed in the fetal hearts. Only in late fetal stages were leptofibrils observed in both cell types.We conclude that in the bovine heart Purkinje fibres develop along a different pathway from ordinary myocytes.This study was supported by grants from the Swedish Medical Research Council (12X-3934), the Faculty of Medicine, University of Umeå, and the Expressen Prenatal Fund     

New attachment – reattachment following reconstructive periodontal surgery

The present study was designed to evaluate if the conditions for reformation of a connective tissue attachment are less favorable on root surfaces which have lost their fibrous attachment because of periodontal disease than on root surfaces surgically deprived of their attachment apparatus. In each of 4 Green monkeys, 2 maxillary and 2 mandibular teeth were selected for experimentation. Periodontal breakdown was produced and allowed to progress to the mid-root level around one of the experimental teeth in both the maxilla and mandible by placing elastic ligatures around the neck of these teeth. 3 months after removal of the ligatures, the crown of the teeth was resected and the epithelium and the subjacent granulation tissue were removed. Using a diamond bur, circumferential defects similar to those obtained by the ligature induced destruction were then produced around the remaining 2 experimental teeth following resection of the crown. The root cementum on both groups of teeth was removed to the level of the reduced bone height. Finally, all roots were submerged to complete coverage by a mucosal flap. After 3 months of healing, the animals were sacrificed and the jaws removed and placed in fixative. After decalcification, histological sections of the experimental roots and their surrounding periodontal tissues were produced. No histological differences in the result of healing were discernible between the specimens of previously periodontitis-affected roots and roots with surgically created defects. New cementum with inserting collagen fibers had formed in the apical part of the instrumented surface in both groups of teeth.(ABSTRACT TRUNCATED AT 250 WORDS)     

Administered activity and metastatic cure probability during radioimmunotherapy of ovarian cancer in nude mice with 211At-MX35 F(ab')2

PURPOSE: To elucidate the therapeutic efficacy of alpha-radioimmunotherapy of ovarian cancer in mice. This study: (i) estimated the minimum required activity (MRA), giving a reasonable high therapeutic efficacy; and (ii) calculated the specific energy to tumor cell nuclei and the metastatic cure probability (MCP) using various assumptions regarding monoclonal-antibody (mAb) distribution in measured tumors. The study was performed using the alpha-particle emitter Astatine-211 (211At) labeled to the mAb MX35 F(ab')2. METHODS AND MATERIALS: Animals were inoculated intraperitoneally with approximately 1 x 10(7) cells of the cell line NIH:OVCAR-3. Four weeks later animals were treated with 25, 50, 100, or 200 kBq 211At-MX35 F(ab')2 (n = 74). Another group of animals was treated with a nonspecific mAb: 100 kBq 211At-Rituximab F(ab')2 (n = 18). Eight weeks after treatment the animals were sacrificed and presence of macro- and microscopic tumors and ascites was determined. An MCP model was developed and compared with the experimentally determined tumor-free fraction (TFF). RESULTS: When treatment was given 4 weeks after cell inoculation, the TFFs were 25%, 22%, 50%, and 61% after treatment with 25, 50, 100, or 200 kBq (211)At-MX35 F(ab')2, respectively, the specific energy to irradiated cell nuclei varying between approximately 2 and approximately 400 Gy. CONCLUSION: As a significant increase in the therapeutic efficacy was observed between the activity levels of 50 and 100 kBq (TFF increase from 22% to 50%), the conclusion was that the MRA is approximately 100 kBq (211)At-MX35 F(ab')2. MCP was most consistent with the TFF when assuming a diffusion depth of 30 mum of the mAbs in the tumors.     

Phagocytosis and Killing of Francisella tularensis by Human Polymorphonuclear Leukocytes

Bacteria of a wild strain of Francisella tularensis were less efficiently killed by human polymorphonuclear leukocytes than were bacteria of an attenuated strain. This finding was explained to some extent by a less efficient phagocytosis, but bacteria of the wild strain also seemed to be more resistant to killing after ingestion.     

Acute cardiovascular responses in preterm infants at 34–39 weeks of gestational age

Background

Premature infants demonstrate immature physiological control mechanisms; however their acute cardiovascular control has not yet been widely studied.

Aim

The aim of this study was to analyze heart rate (HR) and blood pressure (BP) control in preterm infants.

Subjects

Twenty preterm infants with a mean gestational age of 31 ± 2.4 (26–34) weeks at birth were evaluated at a gestational age of 36 ± 1.5 (34–39) weeks. Results were compared to twenty, healthy, full-term, control infants studied at the age of 12 ± 3 weeks.

Outcome measures

HR and BP responses to 45° head-up tilt and side motion tests during non-rapid eye movement sleep were analyzed. In addition, HR responses to spontaneous arousals from non-rapid eye movement sleep were evaluated.

Results

Preterm infants showed significantly smaller initial HR and BP responses compared with controls in head-up tilt (HR p = 0.0005, systolic BP p = 0.02, diastolic BP p = 0.01) and side motion tests (HR p = 0.002, systolic BP p < 0.0001, diastolic BP p < 0.0001). Furthermore, in tilt tests, preterm infants presented with greater intersubject variability in BP responses than controls (systolic BP p = 0.009, diastolic BP p = 0005). Preterm HR responses to spontaneous arousals were similar to controls.

Conclusions

This study indicates immature vestibulo-mediated cardiovascular control in preterm infants compared with term infants. This is seen as attenuated BP responses to side motion test and more labile acute BP control to postural challenge.     

Evidence of the TNF-α System in the Human Achilles Tendon: Expression of TNF-α and TNF Receptor at both Protein and mRNA Levels in the Tenocytes

Understanding adaption to load is essential for prevention and treatment of tendinopathy/tendinosis. Cytokine release in response to load is one mechanism involved in mechanotransduction. The cytokine tumor necrosis factor alpha (TNF-α) is implicated in tendinosis and can induce apoptotic effects via tumor necrosis factor receptor 1 (TNFR1). The complete absence of information concerning the TNF-α system in Achilles tendon is a limitation as mid-portion Achilles tendinosis is very frequent. Purpose: To examine expression patterns of TNF-α and its two receptors (TNFR1 and TNFR2) in human Achilles tendinosis and control tissue and to biochemically confirm the presence of TNF-α in tendinosis tissue. Methods: TNF-α and TNFR1 mRNA were detected via in situ hybridization. TNF-α, TNFR1, and TNFR2 were demonstrated immunohistochemically. Apoptosis markers were utilized. ELISA was used to detect TNF-α. Results: TNF-α and TNFR1 mRNA was detected in tenocytes of both tendinosis and control tendons. Tenocytes from both groups displayed specific immunoreactions for TNF-α, TNFR1, and TNFR2. The widened/rounded tenocytes of tendinosis samples exhibited the most intense immunoreactions. Apoptosis was detected in only a subpopulation of the tenocytes in tendinosis tissue. TNF-α was measurable in tendinosis tissue. Inflammatory cells were not seen. Conclusion: This is the first evidence of the existence of the TNF-α system in the human Achilles tendon. Findings are confirmed at mRNA and protein levels as well as biochemically. The TNF-α system was in principle confined to the tenocytes. The connection between tenocyte morphology and the expression pattern of TNF-α, TNFR1, and TNFR2 suggests that the TNF-α system may be involved in tenocyte activation in Achilles tendinosis.