Evidence for the role of INSL3 on sperm production in boars by passive immunisation.

Insulin-like factor 3 (INSL3), previously called relaxin-like factor, is essential for foetal testis descent and has been implicated in sperm production in adult males. This study investigated the role of INSL3 in sperm production by examining the effect of neutralising INSL3 by passive immunisation on testicular function and sperm output in boars. Six male Duroc boars were randomly assigned to passive immunisation and control groups (n = 3 each). The immunisation group was intravenously injected with an IgG fraction of anti-INSL3 antibody developed against the B domain of INSL3 at 2-week intervals from 21-40 weeks of age. The control group was treated with normal IgG in the same manner. Antibody administration reduced testis weight and caused a fourfold increase in the frequency of apoptotic germ cells, which was associated with upregulation of the pro-apoptotic caspase 3 and BAX, and downregulation of the anti-apoptotic XIAP and BCL2, and a substantial marked reduction in sperm concentration. Neutralising INSL3 delivered by passive immunisation reduced testis weight and sperm concentration by inducing germ cell apoptosis, suggesting that INSL3 acts as a germ cell survival/anti-apoptotic factor in the maintenance of sperm production.

Clinical role for a superantigen in Yersinia pseudotuberculosis infection.

Yersinia pseudotuberculosis is an enteric pathogen that causes a variety of clinical symptoms in the human. Recently, we reported the production of a superantigen (Y. pseudotuberculosis-derived mitogen, YPM) by this organism and characterized the gene structure of ypm. To further study the potential pathogenic role of YPM in Y. pseudotuberculosis infection, we assayed IgG anti-YPM antibodies and T cell antigen receptor-Vbeta expression of the T cells in peripheral blood and in mesenteric lymph node in patients acutely infected with Y. pseudotuberculosis. 20 out of 33 patients (61%) had an elevated antibody titer compared with healthy controls (P = 0.0001). Patients with systemic symptoms such as lymphadenopathy, transient renal dysfunction, and arthritis had significantly higher titers of anti-YPM than patients with gastrointestinal tract symptoms alone. T cells bearing the Vbeta3 gene segment were significantly increased (P = 0.009) among acute phase patients compared with healthy children. During the convalescence phase of the illness, there was a reduction in the abnormal level of Vbeta3 T cells. Moreover, in the mesenteric lymph node, an elevated level of Vbeta3 T cells compared with peripheral blood and a sequence diversity in the junctional region of the T cell antigen receptor beta-chain containing Vbeta3 element was observed in one patient. Together, these findings suggest that YPM was produced in vivo and played an important role in the pathogenesis of Y. pseudotuberculosis infection.

Dual recognition of a human cytotoxic T-cell clone for melanoma antigens.

It is well known that tumor-specific CTLs have a crucial role in the elimination of tumors and that different CTL populations recognize tumor antigens in MHC-restricted and MHC-unrestricted manners. We have established two alpha beta CTL clones that recognize melanoma antigens in both human lymphocyte antigen (HLA)-A2-restricted and HLA-unrestricted manners. Flow cytometry analysis showed that these CTL clones carry CD3, CD8, and alpha beta T-cell receptor (TCR) and express low levels of CD56. In contrast, these CTL clones do not express CD16, indicating that they do not contain natural killer cells. TCR analysis of these CTL clones using an anchored PCR method revealed that each clone carries a single alpha beta TCR. Both CTL clones contained the same Valpha and Vbeta gene segments although they carried different Jalpha and Jbeta gene segments. Taken together, these results confirm that CTL clones that carry a single alpha beta TCR recognize melanoma antigens in both HLA-A2-restricted and HLA-unrestricted manners. It is strongly suggested that the dual recognition of these CTL clones for the melanoma antigens is mediated by TCRs. The novel mechanism for antitumor immunity by these CTLs may be important in the effective elimination of tumors in vivo.

Efficient generation of autologous peripheral blood-derived cytotoxic T lymphocytes against poorly immunogenic human tumors using recombinant CD80-adenovirus together with interleukin 12 and interleukin 2.

To generate CTLs against poorly immunogenic human tumor cells, we transfected the human CD80 gene into the tumor cells using a replication-deficient adenovirus (Ad) vector. The successful surface expression of CD80 was obtained in both cultured tumor cell lines and primary cultured tumor cells. Transduction of CD80 alone was not sufficient to induce cytotoxicity of peripheral blood lymphocytes against allogeneic tumor cell lines except for melanoma cells. We, therefore, investigated a combined effect of CD80-Ad-infected tumor cells and interleukin 12 (IL-12). Although 7-day cultivation of autologous or allogeneic lymphocytes with CD80-Ad-infected tumor cells and IL-12 slightly enhanced cytotoxicity against some allogeneic tumor cells, no substantial cytotoxicity was observed against autologous tumor cells. When we extended the culture period to 14 days in the presence of IL-2, a prominent enhancement of cytotoxicity was observed against both allogeneic and autologous tumor cells. Cytotoxicity against autologous tumor cells, but not against allogeneic tumor cells, was efficiently inhibited by anti-CD3 monoclonal antibody. Furthermore, the selective cytotoxicity against a panel of targets indicated that the induced CTLs recognize specific antigens on autologous tumor cells. These results suggest that stimulation with a combination of IL-12- and CD80-modified tumor cells and subsequent expansion with IL-2 may efficiently generate tumor-specific CTLs from autologous peripheral blood lymphocytes. Our data imply that the combination of CD80 transduction and suitable cytokines is useful for enhancing antitumor immunity to poorly immunogenic human tumors.

Purification and characterization of a novel superantigen produced by a clinical isolate of Yersinia pseudotuberculosis.

A superantigen designated as Yersinia pseudotuberculosis-derived mitogen (YPM) was purified in an equal manner from both the culture supernatant and cell lysate of a clinical isolate (KUR-1) of Y. pseudotuberculosis serotype 4b. A significant proliferative response of human peripheral blood mononuclear cells to purified YPM was detectable even at a concentration of 1 pg/ml. The N-terminal sequence of YPM which included 23 amino acid residues was determined, by automated Edman degradation, as Thr-Asp-Tyr-Asp-Asn-Thr-Leu-Asn-Ser-Ile-Pro-Ser-Leu-Arg-Ile-Pro-Asn-Il e-Ala-Thr-Tyr-Thr-Gly-. This sequence differed from not only all the, hitherto, reported superantigens but also known proteins. While molecular weights of known bacterial superantigens are more than 22,000, electrospray ionization mass spectrometry showed that the molecular weight of YPM was 14524.4. These results indicate that YPM comprises a novel superantigen with substantial structural differences from other bacterial superantigens produced by Gram-positive cocci.

Differential regulation of interleukin-6 production in the kidney by the renal sympathetic nerves in normal and spontaneously hypertensive rats.

OBJECTIVE: The aim of the study was to evaluate the influence of renal sympathetic nerves on the production of interleukin (IL)-6 in the kidney of normotensive Wistar rats and spontaneously hypertensive rats (SHR). DESIGN: In acute studies, the left kidney was exposed and the renal nerves were electrically stimulated to decrease renal blood flow by either 15 or 30% for 1 h. The changes in renal function induced by nerve stimulation were measured and IL-6 production estimated at the end of the experiment. METHOD: Pentobarbitone anaesthetized rats were prepared for the measurement of renal blood flow, glomerular filtration rate and water and sodium excretion. IL-6 production was estimated by the level of IL-6 messenger (m)RNA present in the kidney tissue. RESULTS: At the lower level of nerve stimulation there were reductions in the glomerular filtration rate of 12 and 24% in Wistar and SHR, respectively, and a decrease in sodium excretion of approximately 30% in both rat strains. At higher rates of stimulation these haemodynamic and tubular responses were proportionately larger. The mRNA for IL-6 and beta-actin were measured by densitometric analysis of Northern blot gels following hybridization. Renal IL-6 mRNA levels in the Wistar rat demonstrated that the gene was actively expressed and was increased some threefold by renal nerve stimulation. By contrast, IL-6 mRNA was extremely low in SHR compared with that found in the kidneys of Wistar rats and did not appear to be changed by renal nerve stimulation. CONCLUSIONS: These findings suggest that the renal sympathetic nerves are an important regulatory mechanism for IL-6 production under normal conditions. However, in the SHR, production of IL-6 in the kidney appears to be suppressed.

Renal interleukin-6 production in normotensive and hypertensive rats.

OBJECTIVE: To determine whether renal interleukin-6 was produced constitutively under the normal physiological conditions and to evaluate the influence of hypertension development on interleukin-6 production in two different hypertensive models, the spontaneously hypertensive rat (SHR) and the two-kidney, one clip (2-K,1C) hypertensive rat. DESIGN: In a chronic study, Wistar rats and SHR, aged 4, 5, 7 and 9 weeks, and 2-K,1C Goldblatt hypertensive rats, at 2 and 4 weeks after applying the clip, were anaesthetized, their blood pressures were measured and the kidneys were collected and renal interleukin-6 production estimated. METHOD: The rats were lightly anaesthetized with halothane and prepared for blood pressure measurement via a carotid artery cannula. Interleukin-6 production was estimated from the interleukin-6 messenger RNA (mRNA) present in the kidney tissue. The mRNA species (interleukin-6, beta-actin and renin) were measured by densitometric analysis of the autoradiographs following Northern blot hybridization. RESULTS: The blood pressure was approximately 100 mmHg at all ages in the Wistar rats, but rose from 101 +/- 3 mmHg at age 4 weeks to 154 +/- 2 mmHg at age 9 weeks in the SHR (means +/- SEM, P < 0.01). Constitutive production of renal interleukin-6 could not be detected in either the Wistar rats or the SHR. In 2-K,1C rats the blood pressure was increased significantly at 2 and 4 weeks after clipping to 129 +/- 3 and 140 +/- 4 mmHg (means +/- SEM, both P < 0.01), respectively, and the renal renin mRNA concentration was increased significantly in the clipped and decreased in the non-clipped kidneys at 2 and 4 weeks after clipping. The renal interleukin-6 mRNA could not be measured in either clipped or non-clipped kidneys at either 2 or 4 weeks after clipping. CONCLUSION: These findings demonstrate that renal interleukin-6 was not produced constitutively under normal physiological conditions. Moreover, in spite of the development of hypertension from two causes, genetic and renin-dependent, renal interleukin-6 was not expressed even though there is a deficit in immunological function in the SHR and damage to the renal tissue of the 2-K,1C rats.

Neuro-regulation of interleukin-6 gene expression in the spontaneously hypertensive rat kidney.

OBJECTIVE: To assess the influence of elevated renal sympathetic nerve activity on renal interleukin-6 (IL-6) and interleukin-1 alpha (IL-1 alpha) production and to compare the specificity of the constitutive production of these cytokines in the spleen and kidney of the spontaneously hypertensive rat (SHR). DESIGN: In acute studies, using anaesthetized and surgically stressed rats, the renal nerves either were not stimulated or were stimulated electrically to reduce renal blood flow by 15 or 30% for 1 h. The kidneys were then extracted for analysis. For the chronic study, Wistar rats and SHR aged 9 weeks were briefly anaesthetized and kidneys and spleen extracted for cytokine measurement. METHODS: Tissue samples were subjected to reverse transcriptase and polymerase chain reaction amplification to assess levels of IL-6 and IL-1 alpha. RESULTS: Renal nerve stimulation decreased levels of IL-6 messenger RNA in the SHR kidney, from a control value of 0.677 +/- 0.043 units to 0.624 +/- 0.049 and 0.383 +/- 0.078 units during the 15 and 30% reductions in renal blood flow induced neurally. The chronic experiments showed that, although there was no difference in constitutive production of IL-1 alpha between the kidney and spleen of Wistar rats and SHR, spleen levels of IL-6 were higher in the SHR and IL-6 was expressed constitutively neither in the Wistar rat nor in the SHR kidney. CONCLUSION: These data demonstrate that renal IL-6 gene expression is low in the SHR kidney under conditions of anaesthesia and surgical stress and that it is further decreased when the kidney is subjected to adrenergic influences. These studies help to define the deficiencies and abnormalities of the SHR Immune system.

Regulation of tumour necrosis factor and interleukin-6 gene transcription by beta2-adrenoceptor in the rat astrocytes.

The present study was designed to clarify the role of beta2-adrenoceptors in modulating the level of TNF and IL-6 gene transcription and their respective mRNA accumulations. Astrocytes were transfected with the 5'-flanking region of the TNF and IL-6 genes linked to a luciferase coding sequence as a reporter. The addition of isoproterenol had an inhibitory effect on the TNF and IL-6 promoter activity induced by LPS. The inhibitory effect was blocked in the presence of a beta2-adrenoceptor antagonist but not in the presence of a beta1-adrenoceptor antagonist. TNF and IL-6 mRNA and protein levels in the astrocytes were depressed by beta2-adrenoceptor activation which corresponded to changes in TNF and IL-6 promoter activity. These studies demonstrated that isoproterenol, via beta2-adrenoceptors, suppressed LPS-induced TNF and IL-6 promoter activities, mRNA accumulations, and protein levels in the astrocytes. Beta2-adrenoceptor activation may be an important mechanism for regulating TNF and IL-6 expression in brain diseases.

Attenuation correction in evaluating renal function in children and adults by a camera-based method.

UNLABELLED: Correction for soft-tissue attenuation is required to evaluate absolute renal function by a camera-based method, and an estimate of renal depth and an attenuation coefficient are commonly used for attenuation correction. The first goal of this study was to develop formulas for the calculation of renal depth in both children and adults. The second goal was to optimize the attenuation coefficient for the estimation of renal accumulation of a 99mTc-labeled agent. METHODS: Renal depth was measured by CT in 74 children and 232 adults and compared with the depth calculated using previously published equations. Multiple stepwise linear regression analysis was conducted using data from children and adults together, and new formulas to calculate renal depth were derived. Using the resulting equations, percentage renal uptake at 2-2.5 min was computed from 99mTc-diethylenetriamine pentaacetic acid (DTPA) renography in 40 children and 92 adults. Percentage renal uptake was assessed using various values of an attenuation coefficient, and an optimized attenuation coefficient was determined to maximize the correlation coefficient between percentage renal uptake and glomerular filtration rate (GFR) measured from 2 blood samples. RESULTS: Although the previously published equations appeared to be acceptable in predicting adult renal depth, they substantially underestimated pediatric renal depth. Renal depth (D, cm) was shown by stepwise regression analysis to depend on the ratio of body weight (W, kg) to body height (H, cm) and was successfully calculated in both children and adults using the derived equations (right: D = 16.778 x W/H + 0.752; left: D = 16.825 x W/H + 0.397). The correlation coefficient between percentage renal uptake of 99mTc-DTPA and measured GFR varied substantially according to the attenuation coefficient used and was the highest (0.947) with an attenuation coefficient of 0.087/cm. CONCLUSION: The equations presented here enabled estimation of renal depth irrespective of the patient's age. Attenuation correction using these equations and the optimized attenuation coefficient appears to aid in evaluating renal accumulation and, consequently, renal function in both children and adults.

Influence of ETR-p1/f1 antisense peptide on endothelin-induced constriction in rat renal arcuate arteries.

1. This study set out to examine the endothelin receptor subtypes mediating vasoconstriction in the rat renal arcuate artery. This was done in isolated vessels 120-200 microns in diameter, incubated with a selective agonist and the novel 'antisense' peptide to part of the human endothelinA receptor. 2. Groups of vessels (n = 6) were incubated with increasing concentrations of endothelin-1 (ET-1), from 1 to 100 nM, which caused a 65% maximal contraction at the highest dose with an pEC50 of 8.16 +/- 0.11 M. By contrast, in six other vessels sarafotoxin 6c over the same dose range gave a minimal contraction (around 5% of maximum). 3. Preincubation of six vessels with the antisense peptide ETR p1/f1 at 1 microM had no effect on the ET-1 induced vasoconstriction, in terms of displacement of the concentration-response curve or the maximal tension achieved by the agonist. In the six vessels exposed to 4 microM ETR p1/f1, there was a significant shift of the concentration-response curve and a lower pEC50 at 7.78 +/- 0.09 M (P < 0.05). At the highest concentrations of ETR p1/f1, there was a marked suppression of all responses to ET-1, which at the maximal concentrations tested, 0.1 microM, only reached some 10% of the maximal achievable contraction. 4. Increasing ET-1 concentrations up to 2 microM in vessels incubated with 40 microM ETR-p1/f1 showed that the blockade could be overcome and that the relationship was shifted to the right (P < 0.001) by approximately one log unit with a pEC50 of 7.13 +/- 0.11 M. A Schild plot of the data indicated the antagonist to be acting competitively at a single population of receptors. 5. At the highest concentrations tested, 40 microM, ETR-p1/f1 had no effect on noradrenaline-induced contractions, indicating a lack of non-specific actions. 6. Together, these data suggest that at the rat renal arcuate artery the endothelinA receptor is the predominant functional receptor mediating contraction. Furthermore, this study has shown the potential usefulness of this novel type of 'antisense' peptide in blocking receptor activation.

Structural analysis of HLA-B40 epitopes.

Two genes encoding HLA-B60 or HLA-B61 were cloned from Japanese and the exons of their genes were sequenced. One silent mutation was observed at the exon 1 between HLA-B60 (B*40012) and B*40011. Seven nucleotide substitutions were seen at the exon 3 between HLA-B61 (B*4006) and B*4002. Three substitutions at codon 95, CTC in B*4002 to TGG in B*4006, changed Leu in B*4002 to Trp in B*4006, while two substitutions at codon 97, AGC in B*4002 and ACG in B*4006, changed Ser in B*4002 to Thr in B*4006. Since B*4002 shares the epitope of alloantibodies specific for HLA-B61, two HLA-B61 subtypes are discriminated by two amino acid substitutions at residues 95 and 97. B*40012 and B*4006 differ by four amino acid substitutions on the beta sheet and five amino acid substitutions on the alpha 2 helix. Since the residues at the beta sheet seem hardly to affect the binding of alloantibody, it is suspected that the residues on the alpha 2 helix provide epitopes for alloantibodies that discriminate allospecificity between HLA-B60 and HLA-B61.

Sequence variation in Japanese HLA-DRw8 specificity.

There are four DRw8 haplotypes with different DQ alleles in Japanese: DRw8-DQw6 (w1), DRw8-DQw4, DRw8-DQw8(w3), and DRw8-DQw7 (w3). We previously reported the nucleotide sequence of DRB1 gene of DRw8-DQw6(w1) and it was named DRB1*08032. The nucleotide sequences of the other DRw8 DRB1 alleles and their correspondence to internationally recognized DRw8 subspecificities were still unclear. We have cloned these DRB1 genes and determined the nucleotide sequences. The comparison of the sequences with the published sequences revealed that the differences were occurred at two amino acid positions, and these four haplotypes are classified in two groups: (a) DRw8-DQw6(w1) and DRw8-DQw7(w3), and (b) DRw8-DQw4 and DRw8-DQw8(w3). The DRB1 molecules of DRw8-DQw6(w1) and DRw8-DQw7(w3) have Ser57 and Ile67, and those of DRw8-DQw4 and DRw8-DQw8(w3) have Asp57 and Phe67. The former has the same sequence as that of DRB1*08032, and the latter is same as that of DRB1*0802. The classification corresponds to the serologic subtyping, which divides DRw8 into DR8.1 and DR8.2, reported in the 10th Japan HLA Workshop.

In staphylococcus enterotoxin B (SEB)-stimulated human PBMC, the LAK activity of non-T cells might have a major role in the mechanism of glomerular endothelial cells' injury.

In this study the SEB-activated LAK cytotoxicity was identified and characterized in human peripheral blood lymphocytes (PBMC). After 3 days of SEB stimulation, the PBMC acquired a cytotoxicity against traditional LAK targets, K-562 and Daudi, beside that human glomerular endothelial cells (HGEC) were effectively lysed. The magnetic separation of SEB-stimulated CD5+ T cells revealed that the dominant LAK cytotoxicity remained in the CD5- lymphocyte fraction. The major part of the SEB-generated cytotoxicity of CD5- cells could be blocked with specific antibodies to IL-2 and IFN-gamma. The IFN-gamma pretreatment of HGEC reduced the target sensitivity, but because of the upregulation of MHC class II on HGEC surface, these cells were able to present SEB to CD5+ cells. These results suggested that in bacterial superantigen-mediated infection, the non-T (NK cells-derived) LAK cells might have a primary pathogenic role, and the adverse effect of IFN-gamma, that was massively secreted from superantigen-stimulated cells, requires greater consideration.

Role of beta-adrenoceptor on renal interleukin-6 and tumor necrosis factor in spontaneously hypertensive rats.

We have shown previously in the spontaneously hypertensive rat (SHR) kidney that interleukin-6 (IL-6) and tumor necrosis factor (TNF) mRNA levels were low under conditions of acute anaesthesia and surgical stress. The reasons for the suppression of IL-6 and TNF gene expression in the SHR were investigated by examining the influence of enhanced beta-adrenergic stimulation, high blood pressure, and renal function (renal blood flow, glomerular filtration rate, plasma creatinine levels) on renal IL-6 and TNF mRNAs. The experiments were performed by means of the following three studies; (1) SHR and Wistar rats at 4, 7, 9 week old were injected with lipopolysaccaride (LPS), and then a relationship between blood pressure levels and IL-6 and TNF mRNA levels were estimated, (2) isoproterenol and propranolol were administered into SHR and WKY rats, and the levels of IL-6 and TNF mRNA were compared, (3) under condition of anaesthesia and surgical stress, blood pressure and renal functions in SHR were measured, and then the relationships between these factors and IL-6 or TNF mRNA levels were analyzed. Renal IL-6 and TNF mRNAs in SHR remained low even though blood pressure increased with age and there was no significant correlation between IL-6 or TNF mRNA levels and values of blood pressure or renal function under anaesthesia and surgical stress. However, the inhibition of the IL-6 and TNF mRNAs in SHR was prevented by propranolol treatment. These results suggested that suppression of IL-6 and TNF mRNAs in the SHR kidney could be due to overactivity of beta-adrenergic influences which may importantly contribute to the development of hypertension.

Time-resolved fluoroimmunoassay (TR-FIA) of porcine relaxin.

We developed and validated a new assay system for porcine relaxin that overcame the drawbacks of RIA by adapting time-resolved fluoroimmunoassay (TR-FIA), which was recently introduced as a non-RIA format. The assay system was a solid-phase TR-FIA based on competition for a polyclonal anti-porcine relaxin antibody between europium (Eu)-labeled porcine relaxin and test samples. Antibody-relaxin complexes were then bound to the second antibody coated on the solid phase, achieving rapid and complete separation of bound and free antigen. A standard curve was produced over the range of 1 pg/well to 1000 pg/well. Serum and corpus luteum extracts from pigs in late pregnancy exhibited inhibition curves parallel to that of the relaxin standard, whereas male pig serum caused no displacement of the labeled hormone. No cross-reactivity was seen with other hormones, such as insulin, LH, and FSH, indicating a high specificity of the assay. The sensitivity was 4 pg/well (80 pg/ml), which was high and equivalent to that of the porcine relaxin RIA. The intra-assay and inter-assay coefficients of variation were less than 3.8% and 6.7%, respectively. Recovery of porcine relaxin added to male pig serum sample averaged 103%. The advantages of this TR-FIA were that addition of tyrosine was not necessary for labeling, unlike the RIA, Eu-labeled relaxin was stable enough to allow long-term storage for more than one year, the assay was completed in only 5 h versus two to seven days for the RIA, and no special safety precautions were needed. To validate this TR-FIA, the serum relaxin concentrations during late pregnancy, parturition and early lactation were investigated in pigs. Serum relaxin levels determined by this assay were similar to those obtained previously by RIA. In conclusion, this TR-FIA could replace RIA as the method of choice for assay of relaxin.

High concentrations of immunoreactive inhibin in the plasma of mares and fetal gonads during the second half of pregnancy.

Plasma concentrations of immunoreactive (ir)-inhibin were measured in seven pregnant mares from around Day 140 of gestation to Day 2 after parturition using a heterologous bovine-based radioimmunoassay (RIA). Concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), oestradiol-17 beta, progesterone and relaxin were also measured in the same samples. A marked increase in plasma concentrations of ir-inhibin, FSH and LH occurred between Day 220 and Day 300 of gestation but the concentrations of all three hormones returned to baseline by about Day 320 (three weeks before parturition). In contrast, circulating concentrations of the three placental hormones, oestradiol-17 beta, progesterone and relaxin, increased during the final weeks of pregnancy and then decreased markedly to basal values within two days of parturition. There was a positive correlation between circulating concentrations of ir-inhibin and FSH (r = 0.75, P < 0.01) rather than the expected negative correlation. ir-inhibin was not detected in homogenates obtained at Day 190 of pregnancy and form term placenta, but high concentrations of ir-inhibin were present in homogenates of fetal and newborn gonads. Despite the high concentrations of ir-inhibin in these homogenates, they failed to exert any suppressive bioactivity on FSH secretion by rat pituitary cells cultured in vitro. Furthermore, immunohistochemical staining revealed the presence of inhibin in the interstitial cells of equine fetal gonads at Day 190 of gestation. These findings demonstrate for the first time that high concentrations of ir-inhibin, LH and FSH are secreted into the peripheral circulation of the mare during the second half of pregnancy. However, ir-inhibin present in the plasma of pregnant mares appears to be biologically inactive. This hormone is not presumed to be of placental origin but it is proposed that either the enlarged fetal gonads or the maternal ovaries, or both of these organs, may be a source of inhibin in response to the coincident increase in circulating concentrations of LH and FSH.

Periapical lesions in rats with streptozotocin-induced diabetes.

The purpose of this study was to investigate histologically and histometrically the changes in pulpal periapical tissues after pulpal exposure in streptozotocin-induce diabetic rats. Control rats were injected with citrate buffer. Experimental rats were injected with streptozotocin dissolved in citrate buffer. All animals received a pulpal exposure in the left mandibular first molar. Blood glucose concentration was measured at, 0, 7, 14, 28, and 42 days. All animals were killed at 7, 14, 28, and 42 days after pulpal exposure, and their mandibles were evaluated histologically and histometrically. Blood glucose levels in the experimental rats were significantly higher than those in the control rats. In experimental rats, inflammation in the apical periodontal ligament and root resorption and alveolar bone resorption were more severe than that in control rats. This study also revealed histometrically that, in experimental rats, lesions in the periapical area were significantly larger than those in control rats.

Pulpal and periapical tissue reactions after experimental pulpal exposure in rats.

The purpose of this study was to investigate histologically and histometrically the changes in pulpal and periapical tissues after pulpal exposure in rats. All animals received a pulpal exposure in the left mandibular first molar. Animals were killed at 1 to 56 days after pulpal exposure, and their mandibles were evaluated histologically and histometrically. Histologically, pulpal necrosis extended gradually from the upper part of the pulpal tissue to the apex, with inflammation starting in the periapical tissue at an early stage. As the periapical lesion developed, alveolar bone and cementum resorption was also found. Histometrically, the length of pulpal necrosis increased gradually from 1 to 28 days. The vertical length of the periapical lesion after 14 days was significantly increased, while the horizontal length and the overall area after 7 days were also significantly increased. The periapical lesion extended in a mesiodistal direction at first and then in a vertical direction before expansion ceased.

Effect of traumatic occlusion on periapical lesions in rats.

The effect of traumatic occlusion on periapical lesions in rats was investigated histologically and histometrically. Rats were divided equally into groups A to D. Rats in group A received no treatment; in group B, rats received pulpal exposure of the left mandibular first molar; in group C, a resin plate was cemented onto the occlusal surface of the corresponding maxillary molar; and in group D, the molar pulp was exposed and the resin plate was installed. At 1 and 2 wk, compression of the periodontal ligament and inflammation were less in group D than in group B. Lesions in the periapical periodontal ligament at 1, 2, and 4 wk in group D were significantly smaller than those in group B. This study suggests that traumatic occlusion delayed the enlargement of the periapical lesions in rats.