Comparative 16S rRNA gene sequencing study of subgingival microbiota of healthy subjects and patients with periodontitis from four different countries.

AIM: To investigate the differences between the subgingival microbiota of healthy subjects (HS) and periodontitis patients (PP) from four different countries through a metagenomic approach. MATERIALS AND METHODS: Subgingival samples were obtained from subjects from four different countries. Microbial composition was analysed through high-throughput sequencing of the V3-V4 region of the 16S rRNA gene. The country of origin, diagnosis and clinical and demographic variables of the subjects were used to analyse the microbial profiles. RESULTS: In total, 506 subgingival samples were analysed: 196 from HS and 310 from patients with periodontitis. Differences in richness, diversity and microbial composition were observed when comparing samples pertaining to different countries of origin and different subject diagnoses. Clinical variables, such as bleeding on probing, did not significantly affect the bacterial composition of the samples. A highly conserved core of microbiota associated with periodontitis was detected, while the microbiota associated with periodontally HS was much more diverse. CONCLUSIONS: Periodontal diagnosis of the subjects was the main variable explaining the composition of the microbiota in the subgingival niche. Nevertheless, the country of origin also had a significant impact on the microbiota and is therefore an important factor to consider when describing subgingival bacterial communities.

A novel germ line p53 mutation in intron 6 in diverse childhood malignancies.

Screening for p53 mutations in exons 5 to 8 in 124 pediatric malignancies identified 18 abnormal shifts using single strand conformation polymorphism: 12 were missense mutations and in 6, no mutation was detected in the exon or in the splice donor acceptor sequences. Sequencing was then performed in the adjacent introns, revealing a G to A base substitution at 39 base pairs upstream to exon 7. This mutation was identified in the germ line of five of the patients, and also in the father of one, whose parents were available. For comparison, of the 184 normal controls similarly screened, only one had this mutation (P=0.036). Positive staining of p53 protein was observed in three of the paraffin embedded tissues that were available: brain tumor, rhabdomyosarcoma, and lymphocytes from a normal lymph node from the rhabdomyosarcoma patient. All tumors with the identified intron mutation were Li-Fraumeni syndrome tumors. Sequencing of all exons including splice sites was performed and revealed no mutation. We suggest that this mutation in intron 6 of the p53 gene stabilizes the wild type p53 protein, resulting in its abnormal accumulation. Mutations in the noncoding region of p53 should be further studied.

Metastatic brain involvement in Ewing family of tumors in children.

OBJECTIVE: To evaluate the incidence and clinical characteristics of CNS involvement in Ewing family of tumors (EF) in children. METHODS: Chart reviews of children with EF treated in our center from 1972 to 1997. Clinical and imaging data regarding possible CNS involvement were collected. RESULTS: During this 25-year period, 80 children with EF were treated. Intracranial involvement was found in eight (10%) children: the brain was involved in seven children (8.8%) and a retro-orbital metastasis without parenchymal brain involvement was noted in one child. Metastases were localized intrahemispherically, or in the cerebellum or the basal ganglia. Intracranial spread was hematogenous in five children and by contiguous spread from the skull in three children. Intracranial involvement was diagnosed 1.3 to 11 years from initial presentation. Seizures and hemiparesis were the main neurologic complications. CONCLUSIONS: The rate of parenchymal brain involvement in our patients with EF was 8.8%. Spread was mainly hematogenous. Substantial morbidity was associated with CNS disease, which appeared in most patients late in the course of disease.

Mutations of the adenomatous polyposis coli and p53 genes in a child with Turcot's syndrome.

Turcot's syndrome is a rare heritable complex that is characterized by an association between a primary neuroepithelial tumor of the central nervous system and multiple colonic polyps. The aim of this study was to analyze genetic alterations in a case of Turcot's syndrome in a 10.5-year-old boy in whom a colorectal tumor developed 3.5 years following astrocytoma. An APC germline non-sense mutation at codon 1284 leading to a truncated protein was identified, as was a somatic p53 mutation in the colorectal carcinoma in exon 7, codon 244. The latter was not identified in the primary astrocytoma. However, immunohistochemistry revealed high p53 protein expression in both tumors, suggesting an additional p53 mutation in the primary astrocytic tumor. The diverse p53 mutations observed in this unique syndrome in two different sites and stages of the disease may shed light on the multistep progression of the malignant events.

Familial chronic recurrent pancreatitis in identical twins. Case report and review of the literature.

Familial presentation of chronic recurrent pancreatitis in childhood is rare. The etiology of this illness is obscure, and its hereditary properties are not well defined. Simultaneous occurrence of chronic recurrent pancreatitis in identical twins with the same clinical presentation and similar typical pancreatographic abnormalities is exceptional. Twin sisters, aged 9 years, were admitted to the hospital because of recurrent attacks of pancreatitis. Ultrasound examination revealed an enlarged irregular pancreatic duct in both girls, and endoscopic retrograde cholangiopancreatography showed a distorted duct with multiple strictures and dilatations similar to a "chain of lakes" pattern. Both patients underwent longitudinal pancreatojejunostomy within a month. The therapeutic regimen and preoperative and surgical treatment of such patients are discussed, as is the optimal timing of intervention.

Clinical relevance of molecular diagnosis in childhood rhabdomyosarcoma.

Rhabdomyosarcoma may be divided into three subtypes--embryonal, alveolar, and undifferentiated sarcoma--which can be distinguished by molecular analysis. The authors applied reverse transcriptase-polymerase chain reaction analysis (RT-PCR) to analyze tumor samples from 14 children with rhabdomyosarcoma for the presence of the chimeric PAX3-FKHR transcript resulting from the translocation t(2;13)(q35,q14). Both fresh and paraffin-embedded tissues were used. In only nine specimens was the RNA intact for the analysis. The chimeric transcript was identified in seven samples: four alveolar type, one embryonal type, and two undifferentiated sarcoma. Histologic review was performed in the three samples with discordance between the molecular and histologic findings. A sample from a patient with a diagnosis of embryonal rhabdomyosarcoma on presentation and expression of PAX3-FKHR fusion transcript yielded a small focus of alveolar rhabdomyosarcoma and was reclassified as alveolar rhabdomyosarcoma. One of the samples from a patient with undifferentiated sarcoma was redefined as alveolar subtype; the diagnosis of the second undifferentiated sarcoma remained unchanged, in accordance with the histologic diagnosis. These findings further support the recommendation that molecular analysis be included in the diagnostic workup of childhood small round cell tumors to reach a more accurate diagnosis for tailoring of specific treatment.

A novel germ-line mutation in the noncoding region of the p53 gene in a Li-Fraumeni family.

We identified a novel germ-line p53 mutation in the noncoding, nonsplicing regions of a Li-Fraumeni family. Patients belonging to this family included pediatric medulloblastoma and rhabdomyosarcoma patients and a breast carcinoma patient. Three positions in the p53 gene were analyzed for loss of heterozygosity (LOH). One of the three loci retained heterozygosity, whereas the other two exhibited LOH. Sequence analysis of the third locus identified a change of 5'-CCGGGTGA-3' to 5'-CCAGGTTGGA-3', 63 bp downstream of exon 6. The mutation was identified in the germ line of the two pediatric patients and in each of the related parents. We excluded any additional mutation in the entire coding region of the p53 gene, including splice-site intronic sequences. Strong positive nuclear staining of the p53 protein was detected in both normal and tumor paraffin-embedded tissues. Eighty-five normal persons were negative for this alteration, which thus supports it as a mutation. These results may indicate that genetic changes within the noncoding region of the p53 gene may serve as an alternative mechanism of activating this gene. Mutations in the noncoding region of this gene should be further studied.

Metastatic extraosseous Ewing tumor. Association of the additional translocation der(16)t(1;16) with the variant EWS/ERG rearrangement in a case of cytogenetically inconspicuous chromosome 22.

In Ewing sarcoma and related tumors, recently referred to as the Ewing tumors (ET), t(11;22)(q24q12) and its molecular genetic equivalent, the EWS/FLI-1 rearrangement, characterize approximately 85% of cases, while variant aberrations are rare. A second nonrandom aberration in ET is the unbalanced t(1;16) accompanying the t(11;22) in roughly 17% of cases. We present a 17-year-old man with estraosseous ET and multiple metastases, in whom the only cytogenetically detectable chromosomal aberration was der (16)t(1;16)(q12;q11.2). This finding was confirmed by fluorescence in situ hybridization (FISH). Using the RT-PCR technique, a variant EWS/ERG fusion transcript was noted, resulting from a t(21;22) chromosomal rearrangement which recently demonstrated in roughly 10% of ET. However, data on possible biologic differences in EWS/FLI-1 versus EWS/ERG expressing ET are as yet unavailable. This is the first reported combination of t(1;16) with the EWS/ERG rearrangement. A possible significance of this finding for Ewing tumor progression is discussed.

Anaplastic carcinoma of the thyroid.

A review of 48 cases of anaplastic cell carcinoma of the thyroid gland treated in the Department of E.N.T. of Beilinson Medical Center revealed more than 90% of the patients to be over 50 years of age. Twenty-five percent of the patients showed, histologically, areas of transition from differentiated carcinoma (either papillary or follicular) into anaplastic carcinoma. The patients were treated by surgery and/or irradiation and/or chemotherapy. Twenty-seven patients underwent subtotal or total thyroidectomy and 21 patients underwent biopsy or partial thyroidectomy. The survival rate was very poor, two-year survival rate was 28%. Twenty-eight of the patients (58%) died within one year of diagnosis.

Cutaneous malignant lymphoma: a clinical and pathological study of 13 cases.

Thirteen cases of malignant lymphoma, exclusive of mycosis fungoides, with initial involvement of the skin, were selected from 391 consecutive patients with non-Hodgkin's lymphoma. Their clinical course was correlated to histological subtype. All patients (5/5) with 'favourable' histology had single indurated plaques without extracutaneous involvement, and remained in complete remission for at least 5 years after local radiation therapy. In contrast, all those with 'unfavourable' histology not lost to follow-up (7/7) suffered relapse or died within a 2-year period. They generally had multiple skin lesions and extracutaneous involvement at diagnosis or shortly afterwards. We conclude that histological subtype is an important variable in predicting clinical course in those with cutaneous malignant lymphoma.

Adult respiratory distress syndrome in severely neutropenic children.

It has been suggested that polymorphonuclear cells (PMNs) are required for the development of the adult respiratory distress syndrome (ARDS). We investigated the occurrence of ARDS with acute respiratory failure in 30 children with severe neutropenia (less than 500 PMNs/mm3) who met the clinical diagnostic criteria for ARDS and in whom postmortem histopathology findings were available within 7 days of the onset of ARDS. In 26 patients the histopathology was consistent with ARDS. In 12/26 children no white blood cells (WBC) were found in the lung tissue, 10/26 had moderate infiltration of mononuclear cells, 2/26 had massive tumor cell infiltration, and in 2/26 PMNs were found. Thus, in at least 22/26 patients ARDS developed without neutrophilic infiltration of the lungs. The maximum active lung infection rate was found to be 69% (18/26) by endotracheal and post mortem lung cultures and histology. Thus 5/26 children had ARDS without any WBC in the lung tissue. We conclude, as have other studies in adults that the absence of PMNs does not protect children from the development of ARDS and that the mechanism which involves PMNs is probably only one of several pathways for diffuse alveolar damage, some of which is neutrophil-independent.

Histopathologic high risk factors influencing the prognosis of patients with early breast cancer (T1N0M0).

A retrospective study of 78 women with early breast cancer was undertaken with the aim of detecting histopathologic risk factors that would influence the prognosis of these patients. Histologic tumor type, nuclear grade of tumor, tumor margin, and lymphoid infiltration near the tumor as well as blood vessel invasion and lymphatic tumor emboli were evaluated. The overall 10 year survival rate was 79.2 percent. In correlating the aforementioned criteria against survival rate, it was found that the patients without any of the histopathologic risk factors had a 100 percent rate, whereas those with one risk factor had a 79 percent rate and those with two or more risk factors a 66 percent rate. Nuclear grade and lymphoid infiltration were found to have the highest significance in regard to recurrence and the mortality rate. The findings of this study suggest that in patients classified as having T1N0M0 disease without any of the histopathologic risk factors, operation is the only treatment indicated. Patients with one or more positive risk factors should receive adequate adjuvant therapy in order to increase their survival rate.

Inverting papilloma of the nose and paranasal sinuses.

A series of 30 patients with inverted papillomas of the nose and/or the paranasal sinuses is presented. The inverted papilloma is a rare tumor with an overall incidence varying from 0.5% to 4% of all primary nasal tumors. The incidence of inverted papilloma is much more common in the fifth to seventh decades. An association between inverted papilloma and carcinoma is well established. In the large series of patients, the incidence of malignancy associated with inverted papilloma ranges from 1% to 13%, and in our series 10%. Treatment of inverted papilloma is always surgical. The incidence of recurrence is directly related to the method of surgical treatment. Among our 20 patients who were treated by limited surgery, there was recurrence in 14 cases (70%). By contrast, medial maxillectomy and ethmoidectomy via lateral rhinotomy reduced the recurrence rate dramatically. In our opinion this approach is the surgery of choice in the treatment of inverted papilloma.

Prognosis of intracoronal bleaching with sodium perborate preparation in vitro: 1-year study.

Bleaching materials containing hydrogen peroxide have been used for treating discolored nonvital teeth but their use was occasionally associated with external root resorption. In a previous study it was found that the immediate results of bleaching teeth in vitro were equal for sodium perborate mixed with either water or hydrogen peroxide. The purpose of this study was to compare the bleaching prognosis of sodium perborate mixed with water or hydrogen peroxide over a 1-yr period. Extracted human teeth with intact crowns were discolored with human erythrocytes and bleached by sodium perborate mixed with either 30% hydrogen peroxide (group A), 3% hydrogen peroxide (group B), or water (group C). The bleaching materials were placed in the pulp chambers of the discolored teeth and sealed with IRM. They were replaced with fresh preparations after 3 and 7 days. After 14 days the coronal access cavities were sealed with composite resin and the teeth photographed with a color slide film under standardized conditions. The teeth were stored in artificial saliva for 1 yr and photographed after 3, 6, and 12 months. Two separate evaluators ranked the teeth by comparing them with the shades before and after bleaching. The bleaching success rates of the tested groups at each time interval were compared and analyzed statistically. It was found that after 1 yr all of the teeth in groups A and C maintained their shades. In 20% of the teeth in group B there was color regression. Statistically, these differences were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence of interappointment emergency associated with endodontic therapy.

Endodontic interappointment emergency (EIE) occurs in a low incidence following treatment by qualified operators. The purpose of this study was to assess the incidence of EIE after treatment by undergraduate students and to examine its correlation with preoperative and operative parameters. Randomly selected 334 records were retrospectively surveyed for unscheduled emergency appointments following endodontic treatment by undergraduate students. Treatment included step-back canal preparation in multiple visits with formocresol interappointment dressing. The incidence of EIE was 4.2%, and unrelated to the patients' sex and age or to tooth location. It was significantly higher in nonvital than in vital teeth (p < 0.05), with the highest occurrence in nonvital teeth unassociated with periapical radiolucency. Clinically, EIE was associated with swelling in half of the cases. It is concluded that the incidence of EIE following treatment by undergraduate students is low and related to tooth vitality.

Effect of gutta-percha solvents on calcium and phosphorus levels of cut human dentin.

Fresh intact human teeth were cut and treated with 3 commonly used gutta-percha solvents: chloroform, xylene, and Endosolv-E. Treatment consisted of embedding the specimens of each group for 15 or 30 min in the test solution. After each time interval, the specimens were rinsed, dried, and prepared for surface energy dispersive spectrometric analysis. The calcium and phosphorus levels in each specimen were recorded and the differences between the test groups were statistically analyzed. The changes in the calcium and phosphorus levels following treatment with the gutta-percha solvents were minimal and statistically nonsignificant.

Histological characterization of bleaching-induced external root resorption in dogs.

External root resorption occasionally develops after intracoronal bleaching with hydrogen peroxide. In this study, an experimental model was established to study thermocatalytic bleaching-induced root resorption in dogs. Histological examination after 6 months revealed that 18% of the teeth had root resorption lesions. The lesions could be divided into three types. In type I, root excavations were associated with a dense inflammatory cell infiltrate. Type II lesions were characterized by granulation tissue formation. In type III, the lesions were filled with reparative cementum. The three types probably represent different phases of one process. Calcium hydroxide had no effect on the occurrence or type of resorption. The instability of hydrogen peroxide and the presence of inflammatory resorption lesions 6 months postoperatively suggest hydrogen peroxide-induced toxic radicals or denaturants as potential irritants.

Angioimmunoblastic lymphadenopathy and squamous cell carcinoma of lung.

The development of angioimmunoblastic lymphadenopathy in a patient with a slowly growing squamous cell carcinoma of the lung is reported. The possible relation between the two concomitant conditions in this rare case is proposed.

Simultaneous local recurrence of retroperitoneal paraganglioma with liver metastases.

A 68-year-old woman with a history of a nonfunctional paraganglioma resected 23 years previously presented with an abdominal mass. Tumor metastases to the liver were seen at the second operation. The tumor had a more pleomorphic appearance, but was otherwise similar to the original tumor. We discuss the difficulty of predicting the later malignant behavior of the tumor from the original biopsy specimen.

Leydig's and sertoli cells. Their fine structures in three cases of Klinefelter's syndrome.

Testicular biopsy specimens obtained from three patients with Klinefelter's syndrome were studied by light and electron microscopy. Of note in the ultrastructural findings were the absence of annulate lamellae in the Sertoli cells and the abnormal mitochondria, the presence of microcrystalline formations, and the absence of the crystals of Reinke in Leydig's cells. It is suggested that the impaired hormonal function of the testes in Klinefelter's syndrome may be related to the absence of annulate lamella in the Sertoli cells and the presence of microcrystal formations in Leydig's cells.