Utilization of MO6-G3 immortalized odontoblast cells in studies regarding dentinogenesis

Tooth formation is the result of reciprocal instructive interactions between oral epithelium and cranial neural-crest-derived ectomesenchymal tissues. These interactions lead to the cytodifferentiation of highly specialized matrix-forming cell types, the ameloblast, odontoblast, and cementoblast, that produce the mineralized tissues enamel, dentin, and cementum, respectively. Our laboratory has been developing immortalized dental cell lines representative of these various cell types to facilitate studies on gene regulation, cell differentiation, matrix formation, and mineralization. Odontoblasts are solely responsible for the synthesis and secretion of the dentin extracellular matrix bilayer that consists of non-mineralized predentin and mineralized dentin. The mouse immortalized MO6-G3 cell line expresses the major matrix proteins associated with the odontoblast phenotype, producing a matrix that is capable of mineralization. This cell line serves as a useful tool in studies designed to explore the various processes of dentinogenesis. In this paper, we present studies using the mouse odontoblast cell line MO6-G3 as examples of the various research applications. Studies highlighted are: in vitro promoter studies investigating the tooth-specific gene regulation of the major non-collagenous dentin matrix protein, dentin sialophosphoprotein; regulation of tertiary dentin formation by cytokines, such as transforming growth factor-Beta 1; and the utilization of dentally relevant cells in dental material biocompatibility testing.

[Preservative surgery of medial wall pyriform sinus cancer]

OBJECTIVE

To study the surgical methods and functional outcome of preservative surgery for medial wall pyriform sinus cancer.

METHODS

Seventy-one patients with medial wall pyriform sinus cancer, who were treated surgically between 1985 and 1997, were reviewed. Of the 71 cases, 49 underwent preservative surgery, and 22 total laryngectomy. Preservative surgical procedure was defined as follows: 1. Extent of resection: Supraglottic horizontal partial laryngectomy and resection of medial wall of pyriform sinus were performed in patients without fixation of the true vocal cord, and the section extended to paraglottic space, partial lateral wall of pyriform sinus, preepigottic space, superior-posterior of thyroid cartilage in those with restrained vocal cord motility. Supracricoid hemilaryngopharyngectomy and resection of medical wall and partial lateral wall of pyriform sinus were practiced in those with fixed hemilarynx. Cricoid ring and cervical esophagus were removed partially if the pyriform sinus apex was involved. 2. Reconstruction: Larynx: the remains of epiglottis, perichondrium of thyroid cartilage, the infrahyoid muscular fascia, and the platysmal flap were utilized to restore the defects of larynx. Pyriform sinus: Suturing the remaining pharyngeal mucosa directly to cover the wound if the defect was relatively small. For the large defect produced by extended resections, the pectoralis major myocutaneous flap and deltopectoral flap were used. 3. Surgical treatment of cervical lymphaden: Sixty five out of the 71 cases (91.5%) underwent neck dissection. Of which ipsilateral neck dissection were done in 39 cases, and bilateral neck dissection in 26 cases. 4. All patients received postoperative radiotherapy with doses of 60-75 Gy.

RESULTS

In the group of preservative surgery the 3- and 5-year survival rates were 63.4% and 49.6% respectively, whereas those in the total laryngectomy group were 52.4% and 42.4% respectively. Of the 49 cases with preservative surgery, 71.4% (35/49) had all laryngeal functions restored and 28.6% (14/49) partially restored.

CONCLUSION

Despite the fact that the medial wall pyriform sinus cancer tends to have laryngeal invasion, preservative surgery can be practiced for the majority of the cases with the lesions entirely removed.

[Clinical studies on sternocleidomastoid myoperiosteal flap for cervical tracheal reconstruction]

OBJECTIVE

To introduce the experience of repairing the defect of cervical trachea wall by using the sternocleidomastoid myoperiosteal flap after the anterior or posterior wall of cervical trachea was invaded by cervical neoplasm.

METHOD

Between 1989 to 1998 the sternocleidomastoid myoperiosteal flap was applied in 12 patients with different diseases, among which 3 cases were thyroid carcinoma 5 cases were laryngeal carcinoma, 4 cases were cervical esophageal carcinoma.

RESULT

The operation was successful. 12 patients were decannuated and had normal exercise tolerance. The time from reconstruction to decannulation was ranging from 20 days to 6 months.

CONCLUSION

The sternocleidomastoid myoperiosteal flap is an ideal transplant for cervical tracheal reconstruction.

[Measurement of microvessel density in laryngeal carcinoma and its clinical significance]

OBJECTIVE

To determine the microvessel density (MVD) in laryngeal carcinoma and its clinical significance.

METHOD

Thirty-eight tumor specimens were selected from laryngeal cancer patients from January, 1994 to March, 1996. Histological sections of the tumors were stained immunohistochemically for factor VIII. Using light microscopy, we counted microvessels per 400 x field in the most active areas of tumor angiogenesis.

RESULT

1. The tumor blood vessels, composed of only one layer of endothelium were mainly distributed heterogeneously in the interstitial tissue of laryngeal carcinoma with irregular lumen, poorly developed structure. 2. The MVD in the cancer tissues were statistically higher than that in peritumoral tissues (P < 0.01). 3. The MVD in the cancer tissues in group of patients with metastasis to cervical lymphonodes were statistically higher than in group without metastasis (P < 0.01), the MVD in the cancer tissues in group of advanced cases (III, IV stages) were statistically higher than that in group of early cases (I, II stages, P < 0.01). 4. There was no statistically difference in MVD in the cancer tissue between supraglottic and glottic laryngeal carcinoma patients (P > 0.05). 5. There was no statistically difference in MVD in the cancer tissue among the G1, G2 and G3 group (P > 0.05).

CONCLUSION

The laryngeal cancer blood vessels have some characteristics that don't appear in normal vessels. It is suggested that tumor angiogenesis can promote tumor growth and metastasis and MVD may be a new prognostic indicator of laryngeal carcinoma.

Developmental regulation of dentin sialophosphoprotein during ameloblast differentiation: a potential enamel matrix nucleator

The two major dentin matrix proteins, dentin sialoprotein and dentin phosphoprotein have been shown to be expressed as a single large transcript termed dentin sialophosphoprotein (DSPP). These non-collagenous matrix proteins, identified biochemically by their unique physical-chemical properties, are specific cleavage products of a large parent acidic phosphorylated protein (pI 4.0). Previous studies have shown expression of dentin sialoprotein at the protein level by ameloblasts. The purpose of this study was to determine the temporal-spatial pattern of DSPP expression during amelogenesis. In situ hybridization and immunohistochemistry were performed on sections of developing mouse molars. These data were correlated with RT-PCR analysis of in vitro enamel organ epithelium monolayer cell cultures enriched for ameloblasts. Our data indicates initial expression of the DSPP transcripts and protein during early ameloblast differentiation prior to the secretory phase when the majority of the enamel matrix is formed. Ameloblasts appear to tightly down-regulate DSPP transcription as enamel matrix formation is up-regulated. These data demonstrate DSPP expression during amelogenesis is under highly controlled developmental regulation. Therefore, DSPP may have a primary role in the initial mineralization events of both enamel and dentin, acting as a potential nucleator of hydroxyapatite crystal formation.

[Prognostic significance of CD57+ cell level and pTNM staying system in patients with laryngeal cancer]

OBJECTIVE

To analyze the prognostic value of the pTNM clinical staying system, as well as the CD57+ cells level in peripheral blood samples of the patients with laryngeal carcinoma.

METHOD

The CD57+ cells level of peripheral blood was determined with SAP method in 34 patients with laryngeal carcinoma and 16 normal subjects. The pTNM clinical stage was T1-2 in 13, T3-4 in 21; pN+ in 10, pN0 in 24; supraglottis in 8, glottis in 23; hypoglottis in 3; pathologic differentiation G1 in 11, G2,3 in 23.

RESULT

The CD57+ cells level significantly increased (pN+ vs. pNo). In the 12nd month actual survival were significantly different (T1,2 vs. T3,4, pN0 vs. pN+, G1 vs G2,3, supraglottis vs. glottis and hypoglottis, CD57+ > or = 15% vs. CD57+ < 15%). In the 24th month and 36th month actual survival were significantly different (pN0 vs. pN+, G1 vs G2,3, supraglottis. glottis and hypoglottis, CD57+ > or = 15% vs. CD57+ < 15%). In the 48th month actual survival were significantly different only (pN0 vs. pN+, supraglottis vs. glottis and hypo glottis, CD57+ > or = 15% vs. CD57+ < 15%).

CONCLUSION

These results suggested that the assessment of pTNM system and the CD57+ cells level have significance for prognosis of patients with laryngeal carcinoma.

[The clinical study of tongue flaps repairing after resecting pharyngeal neoplasm and laryngeal neoplasm]

OBJECTIVE

To study the repair methods of the defect after resecting pharyngeal neoplasm and laryngeal neoplasm.

METHODS

Four kinds of tongue flap, such as 1/3 tongue flap, 1/2 tongue base flap, tongue base flap and transverse tongue flap were devised and applied in 15 patients with pharyngeal neoplasm and laryngeal neoplasm.

RESULTS

These tongue flaps were alive in all patients. The wound of 13 patients healed in I stage. Two patients dehiscenced because of infection and healed after treatment. All the patients deglutited well. One-year, 3-year, disease-free survive rate were 92.9% (13/14), 72.7% (8/11) respectively.

CONCLUSION

Tongue flaps are obtained easily, with enough blood flow, adapted to pharyngeal environment, easily alive and low complication in repairing the pharyngeal defect. We think that these tongue flaps should be applied in clinic.

[Histological study of the local-regional invasion of pyriform sinus carcinoma]

OBJECTIVE

In order to offer the basis for the operation of the pyriform sinus carcinoma, the local-regional invasion patterns of the pyriform sinus carcinoma were investigated.

METHODS

Twenty-six surgical specimens obtained from patients who undergone laryngopharyngectomy were subjected to a whole organ section study.

RESULTS

Tumors located in the lateral wall of the pyriform sinus spread mainly towards the lateral wall of the hypopharynx. Tumors located in the inner wall of the pyriform sinus spread mainly towards the larynx and opposite side pyriform sinus, the paraglottic space and thyroid cartilage were particularly frequent invaded. It was rare of the invading of the cricoid cartilage. The invasion of the epiglottis and preepiglottic space across the midline had not been found. There were two invading routines, the paraglottic space and preepiglottic space. The invasion of the paraglottic space was through the aryepiglottic fold and the inner surface of the thyroid cartilage. The invading of the preepiglottic space was through the aryepiglottic fold and the upper part of the inner surface of the thyroid cartilage.

CONCLUSIONS

The invading of the preepiglottic space was not the contraindication of the partial laryngectomy. It is practicable to preserve the laryngeal function in most of the patients while tumors located on the lateral or inner wall of the pyriform sinus. There was a tendency to the invading to the contralateral side in the inner wall of the pyriform or postcricoidarytenoid region. Attention should be paid to the submucosal spreading in the postcricoidarytenoid region.

FHIT gene transcript alterations occur frequently in myeloproliferative and myelodysplastic diseases

Twenty-five primary biopsy samples, obtained from patients diagnosed with chronic/acute myeloproliferative disorders, myelodysplastic disorders, in addition to seven cell lines established from patients with leukemias arrested at different stages of myeloid differentiation, were examined for alterations in an alternatively spliced form of the FHIT gene. Transcript alterations of this gene were detected in 80% of the primary biopsies and in two of the cell lines. Reverse transcription PCR (RT-PCR) detected deletions of one or more specific exons in the translated or untranslated portion of the FHIT gene. Point mutations in exons 3, 4, and 5 of the FHIT gene were also detected in 4 patients by single stranded conformational PCR analysis. Transcript alterations were detected in all primary hematopoietic samples which contained chromosome abnormalities, as well as, in hematopoietic disorders which did not show alterations of the 3p14 region. These findings suggest FHIT gene involvement in the transformation of hematopoietic stem cells to leukemia.

Laparoscopic assisted surgery for Crohn's disease an initial experience and results

The inflammatory process associated with Crohn's disease often makes dissection difficult, even in open surgery. The aim of this study was to assess the technical feasibility, safety and indication of laparoscopic assisted procedures performed in patients with Crohn's disease. Records of patients undergoing surgical operation for Crohn's disease from 1993 to 1998 at our hospital were reviewed. Intestinal resection was performed laparoscopically in 24 patients (LAP) and by open technique in 23 patients(OPEN). No significant differences existed as to age, gender, body-mass-index and previous surgery. In the laparoscopic group, seven operations (CON) were converted to open laparotomy (29%) because of large inflammatory mass and/or fistula. The mean intraoperative blood loss was significantly higher in CON- and OPEN-groups than in LAP-group (P < 0.01). Major complications occurred only in one patient who underwent laparoscopic assisted high anterior resection. Patients who underwent laparoscopic operation tolerated p.o. liquids sooner than patients who underwent open surgery (median: 2 vs. 5 day, P < 0.05). Compared with the CON- and OPEN-groups, patients in LAP-group had lower analgesic requirements (median: 3 vs. 6 and 5 day, P < 0.01). The median postoperative length of stay was significantly shorter in LAP-group than in OPEN-group (median: 11 vs. 14 day, P < 0.05). Our study showed that LAP is technically feasible for Crohn's disease. The preoperative correct diagnosis and selection of indications are very important, because the laparoscopic mobilization and resection may be difficult or impossible in patients with large fixed masses, multiple complex fistulas, or recurrent Crohn's disease.

Cloning, gene expression, and characterization of CP27, a novel gene in mouse embryogenesis

We report the full-length sequencing, tissue-specific expression, and immunolocalization of cp27, a novel gene in mouse embryogenesis. The cp27 gene was isolated and cloned from a mouse E11 lambdagt11 library using a peptide antibody that recognized a distinct expression pattern in mouse craniofacial development. The cp27 gene contains an open reading frame of 295 amino acids corresponding to a predicted molecular mass of 33kDa. On Western blots, a polyclonal antibody against CP27 detected a single epitope at 27kDa. The putative CP27 protein has an isoelectric point of 4.75 and features a distinct helix-loop-helix structure according to prediction algorithms. We have cloned the human cp27 gene and mapped it to a locus on the human chromosome 16 which is in proximity to several loci associated with inherited craniofacial diseases such as fanconi anemia type A. Northern blot analysis of RNA from multiple mouse tissues demonstrated high levels of expression in developing mouse teeth, heart, lung, and liver of a single transcript of approx. 1. 8kbp. In situ hybridization using a radioactive RNA probe resulted in distinct signals in the developing neuroepithelium, cerebellum, heart, lung, liver, teeth, salivary glands, and periosteum of developing bones. Immunohistochemical staining of developing mouse tissues detected epitopes specific for CP27 in the mesenchyme surrounding the primary brain vesicles, in basement membranes, in the periosteum, in salivary glands, and in the stellate reticulum of teeth. Thus, CP27 represents a unique gene product involved in mouse embryogenesis.

Cloning, characterization, and tissue expression pattern of mouse tuftelin cDNA

Tuftelin is a protein that has been suggested to function during enamel crystal nucleation. Published sequences for bovine tuftelin cDNA and genomic clones proposed different reading frames that radically affected the derived amino acid sequence of the tuftelin carboxyl-terminus. We have isolated and characterized a full-length mouse cDNA clone and a partial porcine cDNA clone that include the region of the proposed frame-shift. The mouse tuftelin clone is 2572 nucleotides in length, exclusive of the poly(A+) tail. Translation from the 5'-most ATG yields a protein of 390 amino acids with an isotope-averaged molecular mass of 44.6 kDa and an isoelectric point of 5.9. Comparison of the bovine, mouse, and porcine cDNAs supports the revised bovine tuftelin amino acid sequence and suggests that the bovine tuftelin translation initiation codon be re-assigned to a more 5' ATG. Re-assigning the translation initiation codon lengthens the tuftelin protein by 52 amino acids, 51 of which are identical between bovine and mouse. At the carboxyl-terminus, the revised bovine and the mouse sequences match at 39 of the final 42 amino acid positions, compared with 2 identities with the originally published bovine reading frame. Northern blot analysis reveals that tuftelin is not ameloblast-specific but is expressed in multiple tissues, including kidney, lung, liver, and testis. Two tuftelin RNA messages, of 2.6 and 3.2 kb, were detected. DNA sequence characterization of an RT-PCR amplification product confirmed expression of tuftelin in kidney, and identified an alternatively spliced mouse tuftelin mRNA lacking exon 2.

Genomic organization, chromosomal mapping, and promoter analysis of the mouse dentin sialophosphoprotein (Dspp) gene, which codes for both dentin sialoprotein and dentin phosphoprotein

Our laboratory has reported that two major noncollagenous dentin proteins, dentin sialoprotein and dentin phosphoprotein, are specific cleavage products of a larger precursor protein termed dentin sialophosphoprotein (MacDougall, M., Simmons, D., Luan, X., Nydegger, J., Feng, J. Q., and Gu, T. T. (1997) J. Biol. Chem. 272:835-842). To confirm our single gene hypothesis and initiate in vitro promoter studies, we have characterized the structural organization of the mouse dentin sialophosphoprotein gene. This gene has a transcription unit of approximately 9.4 kilobase pairs and is organized into 5 exons and 4 introns. Exon 1 contains a noncoding 5' sequence, and exon 2 contains the transcriptional start site, signal peptide, and first two amino acids of the NH2 terminus. Exons 3 and 4 contain coding information for 29 and 314 amino acids, respectively. The remainder of the coding information and the untranslated 3' region are contained in exon 5. Chromosomal mapping localized the gene to mouse chromosome 5q21 in close proximity to other dentin/bone matrix genes. Computer analysis of the promoter proximal 1.6-kilobase pair sequence revealed a number of potentially important cis-regulatory sequences; these include the recognition elements of AP-1, AP-2, Msx-1, serum response elements, SP-1, and TCF-1. In vitro studies showed that the DSPP promoter is active in an odontoblast cell line, MO6-G3, with basal activity mapped to -95 bp. Two potential enhancer and suppresser elements were identified in the regions between -1447 and -791 bp and -791 and -95 bp, respectively. The structural organization of the dentin sialophosphoprotein gene confirms our finding that both dentin sialoprotein and dentin phosphoprotein are encoded by a single gene with a continuous open reading frame.

Identification of a novel isoform of mouse dentin matrix protein 1: spatial expression in mineralized tissues

Dentin matrix protein 1 (Dmp1) is an acidic phosphoprotein first identified by cDNA cloning from a rat tooth library. Northern blot hybridization of a variety of tissues detected Dmp1 mRNAs only in odontoblasts, suggesting that this protein was odontoblast specific. In situ hybridization studies showed expression of Dmp1 in odontoblasts with transient expression in secretory ameloblasts. The purpose of this study was to isolate and characterize a mouse Dmp1 cDNA and determine its spatial expression pattern related to other mineralizing tissues. A mouse molar cDNA library was screened with a 32P-labeled Dmp1 polymerase chain reaction amplification product in order to isolate a full-length clone. DNA sequence analysis of the largest mouse Dmp1 cDNA (2802 base pairs [bp]) revealed an open reading frame of 1509 nucleotides encoding a 503 amino acid protein with a single polyadenylation signal. Comparison with rat and bovine Dmp1 sequence showed high homology and the identification of a 45 bp (15 amino acid) insert, representing an alternative spliced mRNA. This 45 bp segment was shown to represent a small exon by DNA analysis of a mouse genomic Dmp1 clone. In situ hybridization studies revealed a much broader Dmp1 tissue expression pattern than previously reported. Dmp1 transcripts were detected in the odontoblast and ameloblasts, osteoblasts, and cementoblasts. Our data indicate that Dmp1 is alternatively spliced, and the primary full-length transcript contains a 45 bp insert which is encoded by a small exon. Therefore, Dmp1 is not a tooth-specific protein but rather is expressed in a number of mineralizing tissues including enamel, bone, and cementum.

[Changes in sexual hormones and bone metabolism disorder in postmenopausal NIDDM patients]

In the present study the bone mineral content (BMC) was measured with a single photoabsorptionmeter in 31 diabetic menopausal females and 45 normal menopausal females, simultaneously the serum level of estradiol (E2), testosterone (T), parathyroid hormon (PTH) and calcitonin (CT) were measured with radioimmunoassay. The results showed, BMC, E2 and CT in diabetic group were significantly lower than in the control group. The serum level of PTH in diabetic group was significantly higher than in the control group. The multiple regression-analysis showed that chiefly the level of E2 in the diabetic group was closely related with BMC. Serum E2 stimulate directly the osteoblasts for the bone reconstruction and increased the bone tissue sensibility to PTH. CT is the antagonistic hormone of PTH and protects the bone mineralization. Hyperglycemia may cause the damage of ovarium and decreased E2-secretion. The lowered E2 level results in combination with elevated PTH and lowered CT level in serum obviously, in loss of a large amount of bone mineral content and in developing the diabetic osteoporosis.

The FHIT gene is alternatively spliced in normal kidney and renal cell carcinoma

FHIT (Fragile Histidine Triad), a putative tumor suppressor gene, was cloned from fetal brain and colon cDNA libraries. Portions of this gene are deleted in esophageal, colon, lung and breast tumors, but this gene has not been found altered in sporadic renal cell carcinomas. We report here an alternatively spliced form of this gene cloned from a kidney cDNA library. This cDNA is 1189 bp in length, and contains an additional 94 bp exon, designated exon 2a (E2a). This novel sequence is located between exon 2 and exon 3 of the FHIT gene's untranslated region and exon 2a is present in all normal kidney tissues and cell lines. Analyses performed on sporadic renal cell carcinoma (RCC) tissues and cell lines, show consistent loss of exon 8 of the FHIT cDNA in almost 60% of the cases. Interestingly, in a familial, as well as, in a metastatic RCC, derived from a patient with the sporadic form, exon 2a and exon 3 are also deleted. Northern analyses with the exon 2a of the familial and the metastatic RCC demonstrates concurrent loss of expression of a 4.4 kb transcript with the loss of the E2a sequence, suggesting that exon 2a of the FHIT gene may play an important role in the oncogenesis of renal cell carcinoma.

[Study on the relationship between intratumor microvessel density and neck metastasis of laryngeal and hypopharyngeal squamous cell carcinomas]

Sixty-one laryngeal and hypopharyngeal squamous cell, carcinoma (LC, HPC) tissue slides were immunochemically stained using LSAB method to study epithelium cells. The results demonstrated that (1) intratumor microvessel density (ITMD) in LC and HPC group was higher than that of the benign group (P < 0.05). ITMD was higher in the subgroup of LC and HPC with positive lymph node positive than that with negative lymph nodes. This result suggest that ITMD is relevant not only to the nature of the tumor, but also to lymph node metastasis. The level of ITMD is an important predictive sign of metastasis. (2) The relationship between ITMD and the clinical staging had no statistic significance (P > 0.05). (3) The analysis on the relationship between ITMD and pathologic differentiation indicated that the level of ITMD raised gradually with the lowering of the pathologic differentiation.

Dentin phosphoprotein and dentin sialoprotein are cleavage products expressed from a single transcript coded by a gene on human chromosome 4. Dentin phosphoprotein DNA sequence determination

Dentin is the major mineralized extracellular matrix of the tooth. The organic components of dentin consist of type I collagen (90%) with 10% noncollagenous proteins, which are also components of bone. Two dentin proteins, dentin sialoprotein and dentin phosphoprotein, have been shown to be tooth-specific being expressed mostly by odontoblast cells. In this study, we screened a mouse molar tooth library for dentin sialoprotein and dentin phosphoprotein cDNA clones. Analysis of the clones resulted in characterization of a 4420-nucleotide cDNA that contained a 940-amino acid open reading frame. The signal peptide and NH2-terminal sequence was 75% homologous to the cDNA sequence of rat dentin sialoprotein. The continued open reading frame, however, contained a RGD sequence followed by a region of repeated aspartic acid and serine residues. This portion of the protein codes for amino acid sequence consistent with that of dentin phosphoprotein. The noncoding region contains three potential polyadenylation signals, two of which were shown to be utilized. Northern blot analysis indicated the presence of two major transcripts of 4.4 and 2.2 kilobases in odontoblasts. Chromosomal mapping localized the gene to human chromosome 4. These data suggest that the previously identified dentin extracellular matrix proteins, dentin sialoprotein and dentin phosphoprotein, are expressed as a single cDNA transcript coding for a protein that is specifically cleaved into two smaller polypeptides with unique physical-chemical characteristics. Therefore, we propose that the gene be named dentin sialophosphoprotein. The location of the human dentin sialophosphoprotein gene on chromosome 4 suggests that this gene may be a strong candidate gene for the genetic disease dentinogenesis imperfecta type II.

Modulation of antioxidant enzymes and programmed cell death by n-3 fatty acids

Studies from our laboratory indicate that n-3 (fish oil, FO) lipids at 10% (w/w) in a nutritionally adequate, semipurified diet, and supplemented with equal levels of antioxidants, extended the life span of lupus-prone (NZB/NZW)F1 (B/W) female mice as compared to n-6 (corn oil, CO) lipids. The early rise of autoimmune disease in CO-fed mice was closely linked to the loss of T-cell function. Both IL-2 production and IL-2 receptor expression were reduced due to the loss of naive T-cells and a rise in memory T-cells. Proliferative response to both mitogens and superantigens (staphylococcal enterotoxins A and B) was higher in FO-fed 6.5-mon-old mice. These changes paralleled decreased PGE2 production by splenic cells from FO-fed mice. Analysis of mRNA expression in different organs revealed differential effects of dietary lipids. In FO-fed mice, transforming growth factor beta 1 (TGF beta 1) expression was decreased in kidneys, but splenic tissues had higher expression of TGF beta mRNA. As TGF beta promotes programmed cell death (PCD), we studied the effects of CO and FO on PCD rates in lymphocytes. Both propidium iodide staining and DNA fragmentation were elevated in lymphocytes of FO-fed mice when compared to CO-fed mice of similar age. Also, increased PCD correlated closely with increased Fas gene expression. Thus, in addition to various other antiinflammatory effects, dietary FO appears to increase PCD and prevent accumulation of self-reactive immune cells in lymphoid organs. Further studies are required to dissect the pro- and antiinflammatory mechanisms associated with dietary n-3 and n-6 lipids in modulating autoimmune disorders or malignancy during aging.

Calorie restriction modulates lymphocyte subset phenotype and increases apoptosis in MRL/lpr mice

Defective expression of the Fas apoptotic gene may account for overproduction of CD4- CD8- B220+ cells (double-negative) in MRL/MpJ-lpr/lpr (lpr) mice. Previous studies have shown that calorie restriction (CR) inhibits the development of autoimmune disease and extends life span in these animals. The present studies describe the effects of CR on the distribution of lymphocyte phenotypes, lymphocyte proliferative response, and cytokine release. The effects of CR on dexamethasone (DEX)-induced apoptosis were also studied using propidium iodide (PI) uptake and DNA fragmentation in splenocytes and lymph node (LN) cells. Weanling female mice were fed a nutritionally adequate semipurified diet either ad libitum (AL) or with 40% fewer calories than AL (CR), and killed at 5 months of age. CR mice had fewer palpable lymph nodes, and decreased serum anti-dsDNA antibodies. Mitogen (ConA, anti-CD3, and LPS) and superantigen (SEB)-induced proliferative response was significantly lower in lymphoid cells from AL fed animals. FACS analysis of cells from CR animals showed decreased CD4- CD8- cells in spleen (1.7-fold, P < 0.025) and LN (1.6-fold P < 0.01) and significantly higher CD4+ (spleen, 1.7-fold, P < 0.0001; LN, 2.6-fold, P < 0.025) and CD8+ (spleen, 1.6-fold, P < 0.001; LN, 5.2-fold, P < 0.005) cells. ConA-stimulated IL-2 release was increased in CR animals (splenocytes, 7.5-fold, P < 0.001; LN cells, 6.1-fold, P < 0.01). Finally, apoptosis in response to Dex was increased in CR animals as indicated by the presence of more PI-positive cells (spleen, 15.8%; LN, 10.7%; P < 0.01) and increased DNA fragmentation. In summary, the amelioration of autoimmune disease in MRL/lpr mice by CR is accompanied by prevention of the rise in 'double-negative' T cells and by maintenance of lymphocyte responsiveness to mitogens and DEX-induced apoptosis at higher levels.

Primary Sjögren's syndrome in men

OBJECTIVE

To describe the clinical expression of primary Sjögren's syndrome (SS) in men, focusing on extraglandular manifestations (EGM) and serological markers of disease.

METHODS

In a cross sectional and comparative study, adult men with primary SS were identified from a cohort study on SS, and 26 age matched adult women with primary SS were selected as a control group. All patients met the European classification criteria for SS. They were compared for demographic, clinical and laboratory findings.

RESULTS

Thirteen men with primary SS were identified. Mean age at onset was 39 (SEM 4) years and mean duration of disease was 7.8 (1) years. Sicca complex or parotitis was the presenting feature in eight patients (61.5%), and an EGM in five (38.5%). During the course of the disease, EGM were present in 12 patients (92%), polyarthralgias and lymphopenia being the most frequent (38.5% each). Rheumatoid factor was positive in 73% of patients, antinuclear antibodies in 85%, anti-(SS-A) in 62%, and anti-(SS-B) in 46%. No statistical differences in the frequency of EGM or in the presence of autoantibodies were observed between men and women. However, men patients were more likely to have EGM.

CONCLUSION

Primary SS in men is an uncommon condition with clinical and serological characteristics similar to those observed in women. Sex hormones may be incriminated in the pathogenesis of SS. However, it remains poorly understood whether sex hormones play a major role in the severity of disease and have any importance with regard to treatment.