Endocrinology: The ovarian hyperstimulation syndrome in in-vitro fertilization: a Belgian multicentric study. I. Clinical and biological features

The multicentric study regroups 128 cases of the ovarian hyperstimulationsyndrome (OHSS) in in-vitro fertilization (IVF) and 256 selectedcontrols. Values of serum oestradiol obtained from differentlaboratories were found to be normally distributed after logarithmictransformation. Comparative study of clinical and biologicalcharacteristics indicates that among OHSS patients (i) meanage was lower; (ii) tubal indications for IVF were less frequent;(iii) polycystic ovary-like conditions (i.e. hyperandrogenism,anovulation, luteinizing hormone/follicle stimulating hormoneratio > 2) were more frequent. OHSS patients displayed ovarianhyper-sensitivity reflected by higher oestradiol peak concentrationsin response to lower dosage of human menopausal gonadotrophinand by a steeper slope of oestradiol increment during stimulation.In these patients, the collection of greater numbers of fertilizableoocytes allowed replacement of more embryos with a good vitalityscore. Ongoing pregnancy rate was found to be higher among theOHSS patients. The following complications were recorded amongOHSS cases: abdominal fluid at echographic examination or clinicalascites (86.7 and 71.1%, respectively); pleural and pericardialeffusion (21 and 3%, respectively); haemoconcentration (71.1%);electrolytic disorders (6.2%). Although significantly differentbetween groups, clinical and biological parameters under studyshowed considerable overlap of their distributions in controland OHSS cases. Therefore, these data must be submitted to discriminantanalysis in order to derive a formula predictive of the riskof OHSS.     

Dynamic changes of the immunoglobulins in patients with severe ovarian hyperstimulation syndrome: efficacy of a novel treatment using peritoneo-venous shunt

PROBLEM: To evaluate the efficacy of continuous auto-transfusion system of ascites (CATSA) for the treatment of patients with severe ovarian hyperstimulation syndrome (OHSS) at the risk of febrile morbidity, the dynamic changes of immunoglobulins in the sera and the peritoneal fluid from patients with severe OHSS treated by CATSA were estimated. METHOD OF STUDY: Ten patients with severe OHSS after superovulation for in vitro fertilization-embryo transfer (IVF-ET) were treated by CATSA. Immunoglobulin concentrations were examined in the serum and in the peritoneal fluid before and after CATSA. As controls, serum samples from 15 infertile women, who did not develop OHSS after the same superovulation protocol, were obtained on the day of mid-luteal period (Control-1). Serum samples from 15 patients with OHSS, who were treated by albumin infusion without paracentesis, were also obtained before and after the treatment (Control-2). RESULTS: Before the treatments, serum immunoglobulin G (IgG) concentrations in patients with severe OHSS treated with CATSA and those in patients of Control-2 were significantly lower than those in patients of Control-1 (P < 0.01). Following CATSA, the concentration of IgG increased in the sera, while it decreased in the peritoneal fluid. CONCLUSIONS: Serum IgG in patients with severe OHSS exuded into their peritoneal cavity, indicating that they might be at the status of immunodeficiency and at the risk of febrile morbidity. However, non-infectious febrile morbidity attributed to endogenous pyrogenic mechanism might be considerable. It is also suggested that CATSA might be effective in improving hypoimmunoglobulinemia of the patients with severe OHSS by the peritoneo-venous shunt.     

Endocrinology: Comparison of gonadotrophin-releasing hormone analogues and human chorionic gonadotrophin for the induction of ovulation and prevention of ovarian hyperstimulation syndrome: a case-control study

Gonadotrophin-releasing hormone analogue (GnRHa) has been suggestedas an alternative to human chorionic gonadotrophin (HCG) fortriggering ovulation, while preventing ovarian hyperstimulationsyndrome (OHSS). Since a prospective, controlled study wouldbe unethical at this point, we used a retrospective, case-selfcontrol approach to compare GnRHa with HCG in that context.A group of 16 in-vitro fertilization (IVF) patients who hadsevere OHSS in previous cycles, in which HCG was given to triggerovulation, were studied in subsequent cycles in which GnRHawas used. Each GnRHa cycle (case) was compared to a previousHCG cycle that resulted in OHSS (self control). None of thesesubsequent cydes resulted in severe OHSS. The use of GnRHa didnot affect the number of oocytes retrieved or their quality.Serum oestradiol concentrations on the day of ovulation triggeringwere signilicantly (P<0.01) higher in the GnRHa cycles comparedto HCG cycles. Exogenous progesterone and oestra diol were effectivein maintaining relatively constant serum oestradiol and progesteroneserum concentrations during the luteal phase. Pregnancy rateper cycle was similar in the two groups. In conclusion, theuse of GnRHa to induce ovulation in IVF patients, who are athigh risk for developing OHSS, effectively eliminates this riskwithout affecting other parameters of the stimulation cycle.     

The role of vascular endothelial growth factor and interleukins in the pathogenesis of severe ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is a dramatic complicationof ovulation induction. In its most severe form, OHSS is characterizedby massive cystic enlargement of the ovaries associated withthird space fluid shift, resulting in the formation of ascitesand pleural effusion. Ascites develops because of increasedperitoneal capillary permeability. In this study we examinedthe role of vascular endothelial growth factor (VEGF) and interleukinsin the pathogenesis of increased capillary permeability. VEGFis a member of the family of heparin binding proteins that actdirectly on endothelial cells to induce proliferation and angiogenesis.VEGF mRNA and protein are expressed by human ovarian granulosaand theca cells late in follicular development and subsequentto ovulation by granulosa and theca cells. Therefore, VEGF isideally positioned to provoke the increased permeability oftheca blood vessels that occurs shortly before ovulation. Hybridizationstudies in the rat and primate ovary have demonstrated VEGFmRNA expression predominantly after the luteinizing hormone(LH) surge known to be essential for OHSS. The gonadotrophin-releasinghormone antagonist results in a decreased mRNA expression, implyingsuch expression is dependent on LH. The expression of VEGF mRNAhas been recently shown to be enhanced by human chorionic gonadotrophin(HCG) in a dose- and time-dependent fashion. These studies confirmthe timely association between VEGF and HCG that has been clinicallyknown for many years to be integral in the development of OHSS.VEGF concentrations in serum, peritoneal fluid and follicularfluid of patients at risk for OHSS have been shown to be significantlyrelated to the development of the syndrome. Furthermore, thekinetics of VEGF in the plasma of patients who actually developsevere OHSS are closely correlated with the clinical courseof the syndrome and with certain biological characteristicsof OHSS and of capillary leakage, such as leukocytosis and increasedhaematocrit. Studies on ascitic fluid from patients with severeOHSS have proved that VEGF is the major capillary permeabilityagent. Incubation with VEGF antiserum decreased the vascularpermeability activity by 70%. Interleukin-2 (IL-2) is the firstof a series of lymphocytotrophic hormones to be recognized aspivotal for the regulation of immune response. However, harddata to confirm its central role in the pathogenesis of OHSSare still lacking, despite the fact that some preliminary studiessuggest a positive association between the pooled follicularfluid IL-2 concentration and the development of OHSS. IL-6 isa mediator of the acute phase response to injury, a systemicreaction characterized by leukocytosis, increased vascular permeabilityand increased synthesis of acute phase proteins by the liver.Significantly higher serum and ascites IL-6 concentrations wereseen in OHSS patients. The immunohistochemical localizationpattern suggested that IL-6 is LH or HCG dependent. However,the use of IL-6 as a predictor for the occurrence of OHSS hasnot been successful. The kinetics of IL-6 in patients with severeOHSS are correlated with the clinical symptoms and the biochemicalparameters known to be associated with the severity of the syndrome,suggesting a possible role for IL-6. Further molecular biologystudies similar to those performed on EGF are needed to confirmif this interleukin is central in the cascade of events. IL-8is a chemoattractant, activating cytokine and a potent angiogenicagent. The peritoneal fluid levels is increased in patientswith severe OHSS; its concentration in peritoneal fluid is increasedin patients with severe OHSS. The place of this interleukinin the cascade of events is as yet undetermined and furtherstudies are needed. In conclusion, molecular biology and clinicalstudies strongly suggest that VEGF is the principal mediatorby which HCG might increase capillary permeability in OHSS.     

Value of serum and follicular fluid cytokine profile in the prediction of moderate to severe ovarian hyperstimulation syndrome

The aim of this study was to examine the role of serum and follicular fluid pro-inflammatory cytokines and vascular endothelial growth factor (VEGF) in the prediction of ovarian hyperstimulation syndrome (OHSS). A total of 156 consecutive women undergoing in-vitro fertilization were recruited. The study group comprised 12 women who subsequently developed moderate (n = 7) or severe (n = 5) OHSS. The two control groups were comprised of a randomized selection of 12 high-risk and 12 low-risk women in whom OHSS did not develop. Serum was collected on days of human chorionic gonadotrophin, oocyte retrieval, and embryo transfer. Serum and follicular fluid concentrations of interleukin (IL)-6, IL-8, tumour necrosis factor-alpha (TNF-alpha), and VEGF were measured. Follicular fluid IL-6 concentrations at the time of oocyte retrieval and serum IL-8 concentrations at the time of embryo transfer were significantly higher in the OHSS compared to the two control groups (P = 0.026 and P = 0.017 respectively). Serum concentrations of TNF-alpha and VEGF showed no statistically significant difference between the OHSS group and the controls at any studied time point. This study suggests that follicular fluid IL-6 concentrations at the time of oocyte retrieval and serum IL-8 concentrations on the day of embryo transfer may serve as early predictors for this syndrome.     

糖尿病大鼠血管糖基化终产物含量与其受体的ICAM—1表达的关系

探讨糖尿病大鼠血管组织糖基化终产物（AGEs)含量与其受体（RAGE）和细胞间粘附因子－1（ICAM－1）表达的关系。复制糖尿病大鼠模型,采用荧光法、RT－PCR及原位杂交方法检测主动脉及心肌组织的AGEs含量以及RAGE和ICAM－1基因的表达。发现糖尿病大鼠主动脉和心肌组织AGEs含量升高（P＜0．01）;RAGE和ICAM－1基因表达增强（P＜0．05－0．05）;AGEs含量与RAGE及ICAM－1呈明显正相关（P＜0．01）;氨基胍治疗可缓解上述指标的变化。提示 AGEs可诱导RAGE和ICAM－1的表达。推测AGEs-RAGE相互作用是引起糖尿病血管内皮细胞功能紊乱和损伤的关键环节。     

单纯疱疹病毒性脑炎小鼠脑组织内ICAM-1 mRNA动态变化及药物影响

目的：了解单纯疱疹病毒性脑炎(HSE)小鼠脑组织内的ICAM-1 mRNA动态变化及药物的影响。方法：采用RT—PCR方法半定量检测小鼠HSE治疗前后ICAM-1 mRNA的表达，并给予阿昔洛韦(ACV)及地塞米松(DEX)治疗，用透射电镜观察药物治疗后脑细胞结构的变化。结果：HSE小鼠在感染后第3天ICAM—1InItNAICAM-1 mRNA的表达开始增加，第4天达高蜂，第5天后逐渐下降；用药物干预的小鼠脑神经细胞改变较轻微，未找到病毒颗粒，毛细血管周围水肿减轻。结论：ICAM-1 mRNA是HSE炎症反应发生过程中的重要环节之一，HSE时早期给予ACV DEX治疗对HSE脑细胞结构有明显保护作用。     

Identification of monoclonal antibodies reactive with the rat homolog of ICAM-1, and evidence for a differential involvement of ICAM-1 in the adherence of resting versus activated lymphocytes to high endothelial cells

We have produced four mAbs reactive with the rat homolog of ICAM-1 (intercellular adhesion molecule-1), and presented evidence to indicate that the ICAM-1 molecule plays a differential role in the binding between high endothelial cells and lymphocytes, depending on the state of lymphocyte activation. The conclusion that the four antibodies (1A29, 6A22, 10A25, 10A56) specifically recognize the rat ICAM-1 homolog was based on: (i) their ability to inhibit homotypic aggregation of PHA-blasts; (ii) SDS-PAGE analysis of the antigen recognized; (iii) antigen distribution as assessed by immunoperoxidase staining of frozen sections; and (iv) cytokine-induced up-regulation of the antigen. Involvement of the ICAM-1 molecule in lymphocyte binding to high endothelial cells, the vital step in lymphocyte extravasation in lymph nodes, was examined by the use of one of the newly developed antibodies, and it was found that binding of activated but not resting lymphocytes to cultured high endothelial cells was significantly blocked by the anti-ICAM-1, implying that ICAM-1 has differential involvement in the adherence of lymphocytes to high endothelial cells and that it may play an important role in dissemination of memory lymphocytes to systemic circulation by facilitating or strengthening the binding to the specialized postcapillary high endothelial venules (HEV).     

Inhibition of DC-SIGN-mediated transmission of human immunodeficiency virus type 1 by Toll-like receptor 3 signalling in breast milk macrophages

The majority of cells in early/colostrum milk are breast milk macrophages (BrMMø) expressing dendritic cell (DC)‐specific intercellular adhesion molecule 3 (ICAM3) grabbing nonintegrin (DC‐SIGN), and the expression level of DC‐SIGN on BrMMø will determine cell‐to‐cell human immunodeficiency virus type 1 (HIV‐1) transmissibility. Thus, one of the strategies to prevent vertical transmission of HIV‐1 through breast‐feeding is to find a way to suppress DC‐SIGN expression on BrMMø. As for the expression of Toll‐like receptors (TLRs) in BrMMø, TLR3 was always seen in BrMMø but not in peripheral blood monocytes (PBMo). Also, the expression of TLR3 was slightly enhanced in BrMMø when the cells were treated with interleukin (IL)‐4. Moreover, when TLR3 was stimulated with its specific ligand, the double‐stranded RNA (dsRNA) poly(I:C), DC‐SIGN expression on BrMMø was reduced even in the IL‐4‐mediated enhanced state. Some reduction may be caused by type I interferons (IFNs), such as IFN‐α/β, secreted from BrMMø. Indeed, both IFNs, particularly IFN‐β, showed a strong capacity to suppress the enhancement of DC‐SIGN expression on IL‐4‐treated BrMMø and such TLR3‐mediated DC‐SIGN suppression was partially abrogated by the addition of anti‐IFN‐α/β‐receptor‐specific antibodies. As expected, DC‐SIGN‐mediated HIV‐1 transmission to CD4‐positive cells by BrMMø was inhibited by either poly(I:C) stimulation or by treatment with type I IFNs. These findings suggest a possible strategy for preventing mother‐to‐child transmission (MTCT) of HIV‐1 via breast‐feeding through TLR3 signalling.     

Role of the lectin domain of Mac-1/CR3 (CD11b/CD18) in regulating intercellular adhesion

Leukocytediapedesis requires that Mac-1/CR3-dependent adhesion be regulated so that cells can move from one attachment site to another. The high affinity adhesion state of Mac-1/CR3 is generated when it forms alectin-dependent complex with the receptor for urokinase plasminogen activator (uPAR; CD87). The extensively glycosylated uPAR binds to the same C-terminal lectin domain of CD11b that had previously been shown to prime Mac-1/CR3 for cytotoxic degranulation in response to β-glucan uPAR and β-glucan compete for a lectin site that is near to the CBRM1/23 epitope (residues 943–1047) at the C-terminus of CD11b, and thus the lectin domain is critical to both the adhesion and cytotoxic functions of Mac-1/CR3. Adhesion is reversed when the uPA enzyme is captured by its receptor (uPAR), causing uPAR to bind to CD11b at a second site (residues 424–440) that is in between the N-terminal I-domain and the divalent cation binding region.     

Comparison of immunoreactivity between two different monoclonal antibodies recognizing peptide and polysialic acid chain epitopes on the neural cell adhesion molecule in normal tissues and lung tumors.

A comparative immunohistochemical study of two different monoctonal antibodies against different epitopes on the neural cell adhesion molecule (N-CAM) was performed. Various normal tissues and lung tumors were examined for reactivity with NCC-LU-243, a monoclonal antibody which recognizes a peptide epitope on N-CAM, and monoclonal antibody 735 (MoAb 735), which reacts with a polysialic acid chain epitope on N-CAM. When acetone-fixed normal tissues were used, the immunoreactivities of MoAb 735 and NCC-LU-243 were not identical. In lung tumors, almost all small cell cancers (SCLC) and carcinoid tumors, and some non-SCLC were stained by both monoclonal antibodies. NCC-LU-243 stained the cell membrane only of almost all SCLC cells and clusters of non-SCLC cells. MoAb 735 stained the cell membrane of SCLC in a patchy manner and not only the cell membrane but also the cytoplasm of some non-SCLC. However cytoplasmic staining was evaluated as ‘not positive’. The number of positive cases and the size of the positive tumor cell population determined by cell membrane staining with MoAb 735 were smaller than those determined with NCC-LU-243 in both SCLC and non-SCLC cases. In routinely formalin-fixed materials, the immunoreactivity of both monoclonal antibodies, especially of NCC-LU-243, decreased after prolonged fixation as in surgically resected and autopsy materials. However, both monoclonal antibodies were found to be useful when materials were fixed for a short period of time as in biopsy specimens.     

Role of defensins in the pathogenesis of chronic lung allograft rejection

Chronic rejection predominantly manifested as bronchiolitis obliterans syndrome (BOS), still remains a major problem affecting long-term outcomes in human lung transplantation (LTx). Donor specific antibodies (DSA) and infiltration of neutrophils in the graft have been associated with the development of BOS. This study determines the role of defensins, produced by neutrophils, and its interaction with α-1-antitrypsin (AAT) towards induction of airway inflammation and fibrosis which are characteristic hallmarks of BOS. Bronchoalveolar lavage (BAL) and serum from LTx recipients, BOS+ (n = 28), BOS− (n = 26) and normal healthy controls (n = 24) were analyzed. Our results show that BOS+ LTx recipients had higher α-defensins (HNP1–3) and β-defensin2 HBD2 concentration in BAL and serum compared to BOS-DSA-recipients and normal controls (p = 0.03). BOS+ patients had significantly lower serum AAT along with higher circulating concentration of HNP–AAT complexes in BAL (p = 0.05). Stimulation of primary small airway epithelial cells (SAECs) with HNPs induced expression of HBD2, adhesion molecules (ICAM and VCAM), cytokines (IL-6, IL-1β, IL-13, IL-8 and MCP-1) and growth-factor (VEGF and EGF). In contrast, anti-inflammatory cytokine, IL-10 expression decreased 2-fold (p = 0.002). HNPs mediated SAEC activation was completely abrogated by AAT. In conclusion, our results demonstrates that neutrophil secretory product, α-defensins, stimulate β-defensin production by SAECs causing upregulation of pro-inflammatory and pro-fibrotic signaling molecules. Hence, chronic stimulation of airway epithelial cells by defensins can lead to inflammation and fibrosis the central events in the development of BOS following LTx.     

The effect of 1-(4,5-dihydro-1H-imidazol-2-yl) isoquinoline on monoamine release and turnover in the rat frontal cortex

Imidazoline-(2) binding sites (I(2)-BS) are widely distributed in rat brain and our studies have shown that drugs selective for these sites regulate central extrasynaptic monoamine concentrations. Radioligand binding studies have recently shown that BU98008 (1-[4,5-dihydro-1H-imidazol-2-yl] isoquinoline) displays high affinity at I(2)-binding sites. The aim of this study was set to assess the pharmacological actions of BU98008 in a functional in vivo model using the technique of in vivo brain microdialysis. Systemic injection of 20 mg/kg BU98008 produced an 85% rise in extracellular noradrenaline levels compared with basal values in the rat frontal cortex. Further experiments demonstrated that peripheral administration of 10 and 20 mg/kg BU98008 elicited a transient 25% elevation in dopamine overflow compared with basal values and simultaneously produced an 18% decrease in extracellular DOPAC (3-4-dihydroxyphenylacetic acid) levels compared to basal values. In addition, BU98008 did not appear to affect serotonergic neurotransmission in the frontal cortex. In conclusion, the present study demonstrates that BU98008 shares some functional similarities with known selective I(2)-BS ligands.     

The anti-inflammatory action of methotrexate is not mediated by lymphocyte apoptosis, but by the suppression of activation and adhesion molecules

Low-dose methotrexate (MTX) is an established and highly effective treatment for severe psoriasis and rheumatoid arthritis; however, its mechanism of action remains unclear. We investigated the effects of low-dose MTX on antigen-stimulated peripheral blood mononuclear cells and explored through which cellular pathways these effects are mediated. We show that MTX caused a dose-dependent suppression of T cell activation and adhesion molecule expression, and this was not due to lymphocyte apoptosis. The suppression of intercellular adhesion molecule (ICAM)-1 was adenosine and folate-dependent, while MTX suppression of the skin-homing cutaneous lymphocyte-associated antigen (CLA) was adenosine-independent. The effect of MTX on CLA, but not ICAM-1, required the constant presence of MTX in cultures. Thus, the suppression of T cell activation and T cell adhesion molecule expression, rather than apoptosis, mediated in part by adenosine or polyglutamated MTX or both, are important mechanisms in the anti-inflammatory action of MTX.     

A transcranial magnetic stimulation study of corticospinal excitability during the observation of meaningless, goal-directed, and social behaviour

Peripheral nerve injury causes a progressive series of morphological changes in spinal microglia, and extracellular ATP stimulates proliferation of microglia and may be involved in neuropathic pain. We defined the precise expression of P2X7 in the spinal cord following peripheral nerve injury. We found that both P2X7 mRNA and protein increased in the spinal cord, with a peak at 7 d after injury. Double labeling studies revealed that cells expressing increased P2X7 mRNA and protein after nerve injury were predominantly microglia in dorsal horn. Pharmacological blockades by intrathecal administration of a P2X7 antagonist (A 438079 hydrochloride) suppressed the development of mechanical hypersensitivity. We present distinct evidence that increases in the number of P2X7 receptors in spinal microglia may play an important role in neuropathic pain.     

Synaptic plasticity in the medial vestibular nuclei: role of glutamate receptors and retrograde messengers in rat brainstem slices

The analysis of cellular-molecular events mediating synaptic plasticity within vestibular nuclei is an attempt to explain the mechanisms underlying vestibular plasticity phenomena. The present review is meant to illustrate the main results, obtained in vitro, on the mechanisms underlying long-term changes in synaptic strength within the medial vestibular nuclei. The synaptic plasticity phenomena taking place at the level of vestibular nuclei could be useful for adapting and consolidating the efficacy of vestibular neuron responsiveness to environmental requirements, as during visuo-vestibular recalibration and vestibular compensation. Following a general introduction on the most salient features of vestibular compensation and visuo-vestibular adaptation, which are two plastic events involving neuronal circuitry within the medial vestibular nuclei, the second and third sections describe the results from rat brainstem slice studies, demonstrating the possibility to induce long-term potentiation and depression in the medial vestibular nuclei, following high frequency stimulation of the primary vestibular afferents. In particular the mechanisms sustaining the induction and expression of vestibular long-term potentiation and depression, such as the role of various glutamate receptors and retrograde messengers have been described. The relevant role of the interaction between the platelet-activating factor, acting as a retrograde messenger, and the presynaptic metabotropic glutamate receptors, in determining the full expression of vestibular long-term potentiation is also underlined. In addition, the mechanisms involved in vestibular long-term potentiation have been compared with those leading to long-term potentiation in the hippocampus to emphasize the most significant differences emerging from vestibular studies. The fourth part, describes recent results demonstrating the essential role of nitric oxide, another retrograde messenger, in the induction of vestibular potentiation. Finally the fifth part suggests the possible functional significance of different action times of the two retrograde messengers and metabotropic glutamate receptors, which are involved in mediating the presynaptic mechanism sustaining vestibular long-term potentiation.     

Differential short-term desensitization to vasopressin,isoproterenol, glucagon,parathyroid hormone and calcitonin in the thick ascending limb of rat kidney

Short-term desensitization to hormone-induced cAMP accumulation was investigated in the medullary (MTAL) and the cortical (CTAL) thick ascending limbs of Henle's loop isolated by microdissection from the rat kidney. The following agonists were studied: vasopressin, glucagon and human calcitonin in the MTAL, and vasopressin, glucagon, human calcitonin, parathyroid hormone (PTH) and the -adrenergic agonist isoproterenol in the CTAL. Isolated tubules were preincubated in vitro for 60 min in the presence or absence of a maximal concentration of one of the five agonists (vasopressin 10 nM, glucagon 10 nM, calcitonin 100 nM, PTH 10 nM, isoproterenol 1 M). Desensitization induced by each agent to its own action was then quantified by measuring the amount of cAMP accumulating in the presence of the phosphodiesterase inhibitor isobutylmethylxanthine and the same agonist concentration as that used during preincubation. In the MTAL, as previously reported, preincubation with vasopressin led to a marked (80%–85%) desensitization to this hormone. A significant hormone self-induced desensitization of about 45% was also obtained with glucagon, but not with calcitonin. In the CTAL, the following order of potency to elicit desensitization was observed: vasopressin (80%) > isoproterenol (50%) > glucagon (30%) > PTH (20%, NS) > calcitonin (10%, NS). Thus, the magnitude of desensitization varied greatly from one hormone to another, but for a given hormone, was of roughly similar extent in both MTAL and CTAL. The strikingly different patterns of desensitization to vasopressin and calcitonin were confirmed by kinetics analysis of cAMP accumulation, which revealed that the action of the former hormone was much more rapidly blunted than that of the latter. It is concluded that vasopressin, isoproterenol and glucagon are all able to induce short-term desensitization in the thick ascending limb, although the extent of the process is specific for each agonist. The different degrees of desensitization to unrelated hormones may indicate variable capacities of the corresponding receptors for undergoing short-term desensitization.     

Antibody and T cell recognition of the light chain of botulinum neurotoxin A in two high-responder mouse strains

We investigated in two inbred mouse strains the submolecular recognition of botulinum neurotoxin type A (BoNT/A) by Abs (B cells) and by T lymphocytes. For mapping, we employed a set of overlapping synthetic peptides that encompassed the entire light (L) chain of BoNT/A. After 3 BoNT/A toxoid injections, BALB/c T cells responded in vitro to challenge by peptides L18 (residues 239-257), L23 (309-327), L27 (365-383), L29 (393-411), or L31 (421-439) and more weakly to peptides L3 (29-47), L9/L10 (113-145), L15 (197-215), L17 (225-243), or L26 (351-369). The other peptides stimulated little or no T cell responses. SJL mice mounted, after 3 BoNT/A injections, stronger T cell responses that were medium-to-strong to peptides L2/L3 (15-47), L10/L11 (127-159), L19 (253-271), or L23 (309-327) and low to peptides L17 (225-243), L21 (281-299), L27 (365-383), or L30/L31 (407-439). After 3 BoNT/A injections, BALB/c and SJL antisera protected mice against lethal BoNT/A doses, but displayed restricted epitope profiles compared to outbred (ICR) mice Abs. BALB/c Abs displayed medium-to-high binding to peptides L4/L5 (43-75), L10/L11 (127-159), L18 (239-257) or L27 (365-383). SJL Abs were high to peptides L4/L5 (43-75), L14 (183-201), L16 (211-229), or L18/L19 (239-271), and medium to peptides L10 (127-145), L11 (141-159), L12 (155-173) or L29 (393-411). The other peptides had little or no binding. Responses to each T cell or Ab epitope were under separate genetic control. T and B (antibody) cell recognition regions may coincide, but there were also regions recognized only by Abs or by T cells.     

Morphological alterations and distribution of occludin in rat testes after bilateral vasectomy

The aim of study was to investigate the fate and the morphology of the cells which constitute the spermatogenic line, and to determine the distribution of occludin in the testis in adult vasectomized Wistar rats. The rats were divided into two groups: control group (sham-operated) and vasectomized group. One, 3 and 6 months after sham and vasectomy operations, testis samples were examined. The weight of the testes was found to be reduced 3 and 6 months after vasectomy. There was vacuolization in the seminiferous tubules one month after vasectomy. The tubules showed severe atrophy 3 and 6 months after vasectomy. The occludin immunolabeling in the 3- and 6-month groups was weak and diffuse, and the density of the protein was found to be decreased. The increase in the number of apoptotic cells was accompanied by a time-dependent decrease in the number of haploid, diploid and tetraploid cells. This study demonstrated that vasectomy causes degeneration in the seminiferous tubules with alterations in occludin distribution with a decrease in the number of spermatogenic cells. Moreover, these alterations increase in a time-dependent manner.     

IQGAP1 activates Tcf signal independent of Rac1 and Cdc42 in injury and repair of bronchial epithelial cells

The process of injury and repair involves spreading, migration and cell proliferation. The functions of Rho GTPases and their effector IQGAP1 are poor known in this process of airway epithelium. In the present study, we employed a widely used in vitro model by scratching a monolayer of BECs. We found that scratching induced decreasing of the GTP-bound Rac1 and Cdc42, but increasing the amounts of IQGAP1 at different time points. Next, we confirmed that IQGAP1 interacted with the constitutively active Rac1 (Rac1^V12) and Cdc42 (Cdc42^V12) rather than the dominant negative Rac1 (Rac1^N17) and Cdc42 (Cdc42^N17). Over-expressions of wild type (WT) IQGAP1 and its mutant (T1050AX2), which was defective to interact with Rho GTPases, induced translocation of β-catenin from the cytoplasm into the nucleus. These results activated Tcf/Lef and increased the expression levels of its target genes of c-myc and cyclin D1. Likewise, the amounts of c-myc and cyclin D1 increased after scratching. Our results suggested that IQGAP1 mediated cell proliferation through activating Tcf in a manner independent of Rac1 and Cdc42 in wound repair of BECs.