Takenori Noikura

Autosomal recessive rough hypoplastic amelogenesis imperfecta. A case report with clinical, light microscopic, radiographic, and electron microscopic observations.

A case is presented of a 12-year-old Japanese girl with nearly complete lack of enamel in the deciduous and the permanent dentitions, coupled with a gross abnormality in the pattern of eruption. There was no family history of a similar condition. Deciduous molars were extracted, and hyperplastic gingival tissue was resected. On the basis of clinical, radiographic, and microscopic findings, a diagnosis of autosomal recessive rough hypoplastic amelogenesis imperfecta was made. The configuration of the abnormal enamel was examined with scanning and transmission electron microscopy as well as with light microscopy. Prismatic structure was virtually absent, and the scant enamel showed globular protrusions superficially. Two different surface structures were identified as covering parts of the enamel. At the ultrastructural level, calcified bodies located in the gingival tissue appeared to be composed, in part, of a dense enamel-like substance and, in part, of a tissue with features of afibrillar cementum.

Severity of synovium and bone marrow abnormalities of the temporomandibular joint in early rheumatoid arthritis: role of gadolinium-enhanced fat-suppressed T1-weighted spin echo MRI.

PURPOSE Our goal was to evaluate the efficacy of dynamic contrast-enhanced fat-suppressed MRI of the temporomandibular joint (TMJ) in detecting early joint involvement in patients with rheumatoid arthritis (RA). METHOD Conventional T1- and T2-weighted, gadolinium-enhanced T1-weighted, and dynamic gadolinium-enhanced fat-suppressed SE imaging sequences were performed in 22 patients with RA. RESULTS The dynamic gadolinium-enhanced fat-suppressed T1-weighted SE sequence was more sensitive than the other techniques in detecting early changes in inflamed synovium of periarticular tissue and in detecting condylar bone marrow involvement. In patients with RA, 17 joints with joint pain showed synovial proliferation in 10 (59%) cases and joint effusion in 4 (24%). Of 14 joints with joint sound, 4 (29%) showed synovial proliferation and 7 (50%) showed joint effusion. A lower positional change of the disk was observed in joints with RA than in those with TMJ disorders (82 patients). CONCLUSION Gadolinium-enhanced fat-suppressed MRI was extremely effective in diagnosing early changes of the inflamed TMJ.

MRI of the temporomandibular joint disk and posterior disk attachment before and after nonsurgical treatment.

PURPOSE Our goal was to investigate the role of serial dynamic contrast-enhanced SPGR MRI in the nonsurgical follow-up of patients with temporomandibular joint (TMJ) pain. METHOD Ten patients (10 joints) with internal derangement of the TMJ were imaged with T1-weighted SE and serial postgadolinium SPGR MR pulse sequences. RESULTS On T1-weighted images prior to treatment, the disk position was normal in one joint and anteriorly displaced without reduction in nine joints. After treatment, the disk remained normally positioned in one joint, was anteriorly displaced without reduction in eight joints, and was anteriorly displaced with reduction in one joint. The dynamic study after treatment showed a decrease in contrast enhancement of the posterior disk attachment in 7 of 10 joints. These seven patients had resolution or reduction in joint pain. CONCLUSION These results suggest an association between a decrease in contrast enhancement of the posterior disk attachment and resolution or reduction in joint pain. This association was much stronger than the association between the clinical findings and the anatomy of the disk.

Temporomandibular disorders: MR assessment of inflammatory changes in the posterior disk attachment during the menstrual cycle.

Purpose Our goal was to correlate the menstrual cycle with joint pain, MR evidence of the disk, and posterior disk attachment in patients with temporomandibular disorders. Method Forty-two women underwent MRI involving conventional T1-and T2-weighted gadolinium-enhanced fat-suppressed SE imaging sequences. Results There was a strong statistical difference in the degree of joint pain between proliferated phase and secretory phase groups (p < 0.005). Joint pain had a tendency to increase at the secretory phase. Significantly less contrast enhancement of the posterior disk attachment was observed in the proliferated phase than in the secretory phase (p < 0.001) or menstrual phase (p < 0.01). In addition, anterior disk displacement without reduction of the temporomandibular joint was closely associated with joint pain. Conclusion Our results suggest that positional changes of the disk and the menstrual cycle may play a role in the degree of joint pain and inflammatory pathology of the posterior disk attachment.

Complement system is involved in anaphylactoid reaction induced by lipopolysaccharides in muramyldipeptide-treated mice.

We previously reported that an intravenous injection of specified bacterial lipopolysaccharides (LPS) induced anaphylactoid shock in muramyldipeptide (MDP)-primed mice of various strains, including LPS-resistant C3H/HeJ, accompanied with occasional mortality of mice within 1 h. Prior to shock, rapid accumulation of blood platelets into the lungs and liver followed by degradation of the platelets and tissue destruction were observed. In this report we present the following evidence suggesting that complement activation by LPS is responsible for the anaphylactoid reaction. In C5-deficient DBA/2 mice, the platelet degradation and anaphylactoid reactions did not occur following injection of Prevotella intermedia LPS, although transient platelet accumulation into the lungs and liver was observed. Anti-complement agents K-76 COOH (C5 inhibitor) and cobra venom factor (C5 consumer) protected MDP-primed C3H/HeJ mice from mortality in the anaphylactoid reaction induced by P. intermedia and Salmonella typhimurium LPS, respectively. K-76 COOH also inhibited platelet degradation, but not accumulation, induced by P. intermedia LPS in C3H/HeN mice. LPS specimens carrying mannose-homopolymer (MHP) prepared from wild-type Klebsiella 03 and Escherichia coli 08 and 09 and recombinant E. coli 08 and 09 strains, which have been reported to markedly activate the human complement system probably through the lectin pathway, induced anaphylactoid reactions in MDP-primed C3H/HeJ mice. In contrast, LPS from R-mutant of Klebsiella 03 and the parental strain of the recombinant E. coli strains, which lacked MHP, did not induce anaphylactoid reaction. Based on these findings together with those of our previous studies, we postulated the following mechanism for the anaphylactoid reaction: strong complement activation by specified LPS preparations induced degradation of platelets which have accumulated in the lungs and liver, resulting in acute inflammation accompanied with severe tissue destruction, especially in the lungs, which in turn leads to anaphylactoid reaction. However, the mechanism of platelet accumulation induced by LPS is not yet clear.

Evaluation of submandibular gland function by sialo-scintigraphy following sialolithectomy

Submandibular gland function following transoral sialolithectomy was examined by 99mTc-pertechnetate sialo-scintigraphy in 10 cases. An intraindividual comparison between the function of the treated gland and that of the contralateral normal gland was made using a time-activity curve. Although glandular recovery was not affected by the duration of symptoms or the existence of the symptom at mealtimes, it was inversely proportional to the size of the calculus. Furthermore, the prognosis was more favorable in patients when the anatomically normal orifice of the submandibular duct was preserved.

Serum calcium-decreasing factor (caldecrin) from porcine pancreas has proteolytic activity which has no clear connection with the calcium decrease

We purified a serum calcium‐decreasing factor, which showed chymotrypsin‐like protease activity, from porcine pancreas to homogeneity, The factor administered to mice intravenously at a dose of 20 μg/kg b.w. decreased serum calcium by 15%. Treatment of the factor with the serine protease inhibitor, PMSF, caused a leftward shift in the dose—response curve, showing strengthened activity. It also caused a decrease in serum calcium and hydroxyproline levels in rats. At a dose of 10 ng/ml, the factor inhibited 45Ca release from cultured fetal long bone stimulated by parathyroid hormone (PTH) and PTH‐related protein, but not by interleukin‐1α, prostaglandin E1 and 1,25‐dihydroxy vitamin D3. No other well‐known pancreatic proteases had these effects. In view of the results of experiments using protease inhibitor and pancreatic proteases, and in view of the specificity of this factor in vitro, we propose that the factor exerts its serum calcium‐decreasing activity most probably not through proteolytic degradation of PTH, but through an inhibition of PTH action on bones by a yet undefined mechanism.

Molecular cloning and expression of human caldecrin

Earlier we reported the primary structure of serum calcium‐decreasing factor (caldecrin) from rat pancreas, a protein which is considered to be a member of the elastase family. In this report, we describe the isolation of the two homologous cDNA clones encoding caldecrin from human pancreas, the structures of which are identical except for one base and the corresponding amino acid residue. These human caldecrin isoforms are composed of a signal peptide of 16 amino acids, a propeptide of 13 amino acids, and a mature form of 239 amino acids. Both recombinant caldecrins showed the same chymotrypsin‐type protease activity and hypocalcemic activity. The hypocalcemic activity of both remained intact even after treatment with PMSF to abolish their protease activity. These results suggest that human caldecrin possesses hypocalcemic activity that has no connection with its protease activity.

Caldecrin proform requires trypsin activation for the acquisition of serum calcium-decreasing activity

Proform serum calcium‐decreasing factor (procaldecrin) was purified from porcine pancreas acetone powder. Procaldecrin showed chymotrypsin activity after trypsin treatment in a time‐ and dose‐dependent manner. Procaldecrin did not possess serum calcium‐decreasing activity but acquired serum calcium‐decreasing activity as well as protease activity after trypsin treatment. However, PMSP treatment after activation of procaldecrin by trypsin did not affect the serum calcium‐decreasing activity, even though protease activity was nullified by treatment with PMSF. These findings suggest that the serum calcium‐decreasing activity acquired by procaldecrin requires confonnational change caused by trypsin treatment.

Interpretation of scintigraphy of papillary cystadenoma lymphomatosum (Warthin's tumor) on the basis of histopathologic findings

OBJECTIVES The accumulation of 99mTc-pertechnetate in Warthins tumor was estimated scintigraphically and histopathologically to determine the role of the epithelial component in scintigraphy. STUDY DESIGN Six cases underwent histopathologic examination and scintigraphic evaluation with 99mTc-pertechnetate. Histopathologically the tumors were classified into types according to the epithelial component and cystic space and compared with scintigraphic results evaluated by dynamic radioactive index and wash-out image. RESULTS Histopathologic and scintigraphic observations showed an adequate correlation. Cases with a large epithelial component and poor cystic space showed a large radioactive index of dynamic scintigraphy and hot accumulation of wash-out image. CONCLUSION The scintigraphic results were chiefly due to the epithelial component, but the influence of the cystic space could not be disregarded.