Evaluation of the Effect of Platelet-Rich Fibrin on the Alveolar Osteitis Incidence and Periodontal Probing Depth after Extracting Partially Erupted Mandibular Third Molars Extraction

Aims

To evaluate whether the alveolar osteitis (AO) incidence after extracting partially erupted third molars differs when platelet-rich fibrin (PRF) is administered in the alveolar socket and to assess the influence of PRF on postoperative pain levels and periodontal probing depth.

Settings and Design

In this split-mouth randomized study, 50 patients (17 men/ 33 women; mean age, 23.96 years) with bilateral symmetric partially erupted mandibular third molars were enrolled.

Material and Methods

PRF was randomly placed in one extraction socket, whereas the other socket was left empty. A verbal rating scale was used to evaluate postoperative pain levels. AO development was evaluated on the 7th postoperative day. At 3 months postoperatively, periodontal probing depth was measured on the distal surface of the second molars.

Results

In total, 8% of patients in the PRF group and 18% of the patients in the control group were diagnosed with AO. None of the smokers in the PRF group and 37.5% smokers in the control group were diagnosed with AO. Mean postoperative pain levels were lower in the PRF group than in the control group at all time points. At 3 months postoperatively, periodontal probing depths were found to be ≤3 mm in both groups.

Conclusions

PRF significantly reduced the AO incidence among smokers and had a positive effect on postoperative pain levels but not on periodontal healing.

Circadian periodicity of intestinal Na+/glucose cotransporter 1 mRNA levels is transcriptionally regulated

Intestinal expression of the high affinity Na+/glucose cotransporter 1 (SGLT1), which absorbs dietary glucose and galactose, exhibits both circadian periodicity in its activity and induction by dietary carbohydrate. Because the daily variation in SGLT1 activity is established by the feeding schedule (whether ad libitum or imposed) and persists in the absence of food, this variation has been described as anticipatory. To delineate the mechanisms regulating SGLT1, its expression was examined in rats maintained in a 12-h photoperiod with free access to chow. SGLT1 mRNA levels varied significantly, with the maximum abundance occurring near the onset of dark and the minimum near the onset of light. The SGLT1 transcription rate was 7-fold higher in the morning (1000-1100 h) than in the afternoon (1600-1700 h). An element for hepatocyte nuclear factor 1 (HNF-1) was identified in the SGLT1 promoter that formed different complexes with small intestinal nuclear extracts, depending on the time when the source animal was killed. Serological tests indicated that HNF-1alpha was present in complexes throughout the day, while HNF-1beta binding exhibited circadian periodicity. We propose that exchange of HNF-1 dimerization partners contributes to circadian changes in SGLT1 transcription. Because SGLT1 mRNA levels also varied in rhesus monkeys (offset by approximately one-half day from rats), a similar mechanism appears to be present in primates.

Differential contributions of BRCA1 and BRCA2 to early-onset breast cancer

BACKGROUND

Germ-line mutations in the BRCA1 and BRCA2 genes predispose women to breast cancer. BRCA1 mutations are found in approximately 12 percent of women with breast cancer of early onset, and the specific mutation causing a deletion of adenine and guanine (185delAG), which is present in 1 percent of the Ashkenazi Jewish population, contributes to 21 percent of breast cancers among young Jewish women. The contribution of BRCA2 mutations to breast cancer of early onset is unknown.

METHODS

Lymphocyte specimens from 73 women with breast cancer diagnosed by the age of 32 were studied for heterozygous mutations of BRCA2 by a complementary-DNA-based protein-truncation assay, followed by automated nucleotide sequencing. In addition, specimens from 39 Jewish women with breast cancer diagnosed by the age of 40 were tested for specific mutations by an allele-specific polymerase chain reaction.

RESULTS

Definite BRCA2 mutations were found in 2 of the 73 women with early-onset breast cancer (2.7 percent; 95 percent confidence interval, 0.4 to 9.6 percent), suggesting that BRCA2 is associated with fewer cases than BRCA1 (P=0.03). The specific BRCA2 mutation causing a deletion of thymine (6174delT), which is found in 1.3 percent of the Ashkenazi Jewish population, was observed in 1 of the 39 young Jewish women with breast cancer (2.6 percent; 95 percent confidence interval, 0.09 to 13.5 percent), indicating that it has a small role as a risk factor for early-onset breast cancer. Among young women with breast cancer, there are BRCA2 mutations that cause truncation of the extreme C terminus of the protein and that may be functionally silent, along with definite truncating mutations.

CONCLUSIONS

Germ-line mutations in BRCA2 contribute to fewer cases of breast cancer among young women than do mutations in BRCA1. Carriers of BRCA2 mutations may have a smaller increase in the risk of early-onset breast cancer.

Heterozygous ATM mutations do not contribute to early onset of breast cancer

Ataxia telangiectasia (AT) is a recessive syndrome, including cerebellar degeneration, immunologic defects and cancer predisposition, attributed to mutations in the recently isolated ATM (ataxia telangiectasia, mutated) gene. AT is diagnosed in 1/40,000 to 1/100,000 live births, with carriers calculated to comprise approximately 1% of the population. Studies of AT families have suggested that female relatives presumed to be carriers have a 5 to 8-fold increased risk for developing breast cancer, raising the possibility that germline ATM mutations may account for approximately 5% of all breast cancer cases. The increased risk for breast cancer reported for AT family members has been most evident among younger women, leading to an age-specific relative risk model predicting that 8% of breast cancer in women under age 40 arises in AT carriers, compared with 2% of cases between 40-59 years. To test this hypothesis, we undertook a germ-line mutational analysis of the ATM gene in a population of women with early onset of breast cancer, using a protein truncation (PTT) assay to detect chain-terminating mutations, which account for 90% of mutations identified in children with AT. We detected a heterozygous ATM mutation in 2/202 (1%) controls, consistent with the frequency of AT carriers predicted from epidemiologic studies. ATM mutations were present in only 2/401 (0.5%) women with early onset of breast cancer (P = 0.6). We conclude that heterozygous ATM mutations do not confer genetic predisposition to early onset of breast cancer.

Prevalence of germ-line mutations in p16, p19ARF, and CDK4 in familial melanoma: analysis of a clinic-based population

Five to ten percent of individuals with melanoma have another affected family member, suggesting familial predisposition. Germ-line mutations in the cyclin-dependent kinase (CDK) inhibitor p16 have been reported in a subset of melanoma pedigrees, but their prevalence is unknown in more common cases of familial melanoma that do not involve large families with multiple affected members. We screened for germ-line mutations in p16 and in two other candidate melanoma genes, p19ARF and CDK4, in 33 consecutive patients treated for melanoma; these patients had at least one affected first or second degree relative (28 independent families). Five independent, definitive p16 mutations were detected (18%, 95% confidence interval: 6%, 37%), including one nonsense, one disease-associated missense, and three small deletions. No mutations were detected in CDK4. Disease-associated mutations in p19ARF, whose transcript is derived in part from an alternative codon reading frame of p16, were only detected in patients who also had mutations inactivating p16. We conclude that germ-line p16 mutations are present in a significant fraction of individuals who have melanoma and a positive family history.

Germ-line BRCA1 mutations in Jewish and non-Jewish women with early-onset breast cancer

BACKGROUND

Mutations in a germ-line allele of the BRCA1 gene contribute to the familial breast cancer syndrome. However, the prevalence of these mutations is unknown in women with breast cancer who do not have the features of this familial syndrome. We sought BRCA1 mutations in women who were given a diagnosis of breast cancer at an early age, because early onset is characteristic of a genetic predisposition to cancer.

METHODS

Clinical information and peripheral-blood mononuclear cells were obtained from 418 women from the Boston metropolitan area in whom breast cancer was diagnosed at or before the age of 40. A comprehensive BRCA1 mutational analysis, involving automated nucleotide sequencing and a protein-truncation assay, was undertaken in 30 of these women, who had breast cancer before the age of 30. In addition, the BRCA1 mutation 185delAG, which is prevalent in the Ashkenazi Jewish population, was sought with an allele-specific polymerase-chain-reaction assay in 39 Jewish women among the 418 women who had breast cancer at or before the age of 40.

RESULTS

Among 30 women with breast cancer before the age of 30, 4 (13 percent) had definite, chain-terminating mutations and 1 had a missense mutation. Two of the four Jewish women in this cohort had the 185delAG mutation. Among the 39 Jewish women with breast cancer at or before the age of 40, 8 (21 percent) carried the 185delAG mutation (95 percent confidence interval, 9 to 36 percent).

CONCLUSIONS

Germ-line BRCA1 mutations can be present in young women with breast cancer who do not belong to families with multiple affected members. The specific BRCA1 mutation known as 185delAG is strongly associated with the onset of breast cancer in Jewish women before the age of 40.

Genetic heterogeneity of hepatocellular carcinoma

We studied 80 hepatocellular carcinomas from three continents for p53 gene (TP53) mutations and hepatitis B virus (HBV) sequences. p53 mutations were frequent in tumors from Mozambique but not in tumors from South Africa, China, and Germany. Independent of geographic origin, most tumors were positive for HBV sequences. X gene coding sequences of HBV were detected in 78% of tumors, whereas viral sequences in the surface antigen- and core antigen-encoding regions were present in less than 45% of tumors. These observations indicate that hepatocellular carcinomas are genetically heterogeneous. Mozambican-type of hepatocellular carcinomas are characterized by a high incidence of p53 mutations related to aflatoxins. In other tumors, the rarity of p53 mutations combined with the frequent presence of viral X gene coding sequences suggests a possible interference of HBV with the wild-type p53 function.