Susceptibility of Nd:YAG laser-irradiated root surfaces in replanted teeth to external inflammatory resorption

Abstract— NdYAG laser-induced modification of the root surface may inhibit development of external inflammatory resorption in replanted teeth. This study tested this hypothesis in vivo. The pulp chambers of six mandibular premolars in each of two dogs were accessed, inoculated with plaque, and sealed (Groups 1, 2). Two additional premolars in each dog were endodontically treated without inoculation (Groups 3, 4). After 2 weeks, teeth were hemisected and extracted. Each root had a 2times3 mm surface area denuded of cementum on the buccal and lingual surface. In Groups 1 (n= 12 roots) and 3 (n=4), the denuded surfaces were wiped with 15% EDTA, coated with black ink, and irradiated with Nd:YAG laser (0.75 W, 15 ppc, 300 pm tip, 20 s). In Groups 2 (n= 12) and 4 (n= 4), the surfaces were wiped with 15% EDTA, and rinsed with sterile saline for 20 s. Roots were replanted within 5 min. The dogs were perfwion-euthanised 10 weeks after replantation. Block specimens were removed, decalcified, embedded and horizontally sectioned (6 pm) at 180-pm intervals, resulting in 10 to 14 cross-sections of each root. From these, the middle five consecutive sections were stained with hematoxylin and eosin, and observed by light microscopy for occurrence of surface, inflammatory and replacement resorption on the denuded surfaces. No obvious differences were noted between the laser-irradiated and non-irradiated surfaces. Inflammatory resorption was frequent in Groups 1 and 2, and absent in Groups 3 and 4. Replacement resorption was minimal in Groups 1 and 2, and frequent in Groups 3 and 4. Differences between Groups 1 and 2, and between Groups 3 and 4 were not significant, whereas the differences between the two pairs of groups were statistically significant (chi-square and two-way ANOVA, P>0.006). These results did not support the hypothesis, and questioned the clinical validity of the surface modification in NdYAG laser-irradiated den-tin. Therefore, the clinical application of NdYAG laser to the root surfaces of replanted teeth is not warranted.     

An electron microscopic study of local anesthetic-induced skeletal muscle fiber degeneration and regeneration in the monkey

An electron microscopic study was done on abductor pollicis brevis muscles of 18 Rhesus monkeys after intramuscular injections of 0.75% bupivacaine, 2% mepivacaine, or 2% lidocaine + epinephrine. The muscles were examined for from 2 h to 28 days. Severe muscle fiber damage, consisting of breakdown of sarcolemma and myofibrils, was seen as early as 2 h. Phagocyte mediated fragmentation of the degenerating muscle fibers was at its peak during the third and fourth days. Myoblasts were abundant during the fourth day. Early myotubes appeared on the fifth and sixth days, and they matured during the second week. Satellite cells appeared alongside mature myotubes. Overall, the local anesthetic-induced breakdown and regeneration of skeletal muscle fibers in the monkey followed a course quite similar to that seen in the rat.     

Antigenic variation among Borrelia spp. in relapsing fever.

Seven antigens of Borrelia hermsii, B. parkeri, and B. turicatae with isoelectric points in the range of 4.4 to 5.0 and molecular masses of 40 to 43 kilodaltons played a role in the relapse phenomenon of relapsing fever. Based upon location of the antigens in the outer envelope, the molecular weight, and Western blot analysis, the antigens from each phase of spirochetemia appeared to be a mixture of the serotype-specific antigens of cloned B. hermsii.     

Hemangiosarcoma of the abdominal wall following irradiation therapy of endometrial carcinoma.

A hemangiosarcoma of the abdominal wall developed in a long-standing, nonhealing radiation-induced ulcer ten years after therapeutic irradiation for endometrial carcinoma.     

Porokeratosis of mibelli in transplant recipients

Four of 602 renal and hepatic transplant recipients had porokeratosis of Mibelli develop in the posttransplant period. Porokeratosis is an uncommon, autosomally dominant inherited disorder that presents in adolescence as a proliferation of an abnormal clone of epidermal cells. Clinically, it is characterized by nonhealing plaques that develop most commonly on the limbs. Porokeratosis, a premalignant condition, must be added to the list of potential cutaneous complications seen in immunosuppressed organ transplant recipients.     

Bilateral pheochromocytoma and islet cell adenoma of the pancreas

An 18-year-old woman with bilateral pheochromocytomas and an asymptomatic islet cell adenoma of the pancreas represents the 11th patient to be described with this combination of endocrine tumors. No other components of any multiple endocrine adenomatosis (MEA) syndromes were present. Because of this "overlap syndrome," in which tumors that have traditionally been considered to be components of separate and mutually exclusive MEA syndromes have occurred concomitantly in the same patient, a question is raised regarding the validity of a rigid classification of these various MEA syndromes. The possibility of a pancreatic tumor should be kept in mind in any patient with a pheochromocytoma, especially if it is bilateral of multicentric in origin.     

Pituitary-adrenocortical responses to the chronic administration of granulocyte colony-stimulating factor in rats

Granulocyte colony-stimulating factor (G-CSF) is a hematopoietic growth factor, but it may play a role in the regulation of the neuroendocrine system activity. Only few data are available about its possible influence on the pituitary gland. We have recently reported an acute stimulatory effect of G-CSF (and of GM-CSF) on adrenocorticotropic hormone (ACTH) secretion in rats in vivo. The purpose of the present study was to evaluate whether chronic administration of G-CSF affects ACTH and corticosterone secretion and growth processes of the rat anterior pituitary gland and adrenal cortex in vivo. We have demonstrated that G-CSF (at a dose of 10.0 microg/kg body weight (BW)) injected s.c. once daily (for 7 days), stimulated both ACTH and corticosterone secretion. Simultaneously, G-CSF treatment did not change the total anterior pituitary cell proliferation as revealed by immunohistochemical staining of proliferating cell nuclear antigen (PCNA). On the other hand, proliferative activity of corticotrophs, detected in the sections of the anterior pituitary using double-labeling. was significantly increased after treatment with G-CSF. Moreover, this growth factor induced an increase in the proliferation ratio in the entire adrenal equatorial section. These findings suggest an involvement of G-CSF in the regulation of pituitary-adrenal axis and support the hypothesis of bidirectional associations between the immune system and the endocrine glands.     

Melatonin nephroprotective action in Zucker diabetic fatty rats involves its inhibitory effect on NADPH oxidase

Excessive activity of NADPH oxidase (Nox) is considered to be of importance for the progress of diabetic nephropathy. The aim of the study was to elucidate the effect of melatonin, known for its nephroprotective properties, on Nox activity under diabetic conditions. The experiments were performed on three groups of animals: (i) untreated lean (?/+) Zucker diabetic fatty (ZDF) rats; (ii) untreated obese diabetic (fa/fa) ZDF rats; and (iii) ZDF fa/fa rats treated with melatonin (20 mg/L) in drinking water. Urinary albumin excretion was measured weekly. After 4 wk of the treatment, the following parameters were determined in kidney cortex: Nox activity, expression of subunits of the enzyme, their phosphorylation and subcellular distribution. Histological studies were also performed. Compared to ?/+ controls, ZDF fa/fa rats exhibited increased renal Nox activity, augmented expression of Nox4 and p47^phox subunits, elevated level of p47^phox phosphorylation, and enlarged phospho‐p47^phox and p67^phox content in membrane. Melatonin administration to ZDF fa/fa rats resulted in the improvement of renal functions, as manifested by considerable attenuation of albuminuria and some amelioration of structural abnormalities. The treatment turned out to nearly normalize Nox activity, which was accompanied by considerably lowered expression and diminished membrane distribution of regulatory subunits, that is, phospho‐p47^phox and p67^phox. Thus, it is concluded that: (i) melatonin beneficial action against diabetic nephropathy involves attenuation of the excessive activity of Nox; and (ii) the mechanism of melatonin inhibitory effect on Nox is based on the mitigation of expression and membrane translocation of its regulatory subunits.