The Fas system in the seminiferous epithelium and its possible extra-testicular role

The Fas system is involved in the control of immune system homeostasis and nonfunctional Fas system leads to autoimmune disease in mice and humans. The Fas system is a mechanism through which cells expressing Fas ligand (FasL) induce apoptosis of Fas expressing cells. In mouse and rat, the testis represents the main source of constitutive FasL in the body. The roles so far proposed for this molecule in the testis, such as maintenance of immunoprivilege and regulation of physiological germ cell apoptosis, need to be reconsidered as both hypotheses are based on an erroneous cellular location of FasL in the seminiferous epithelium. Recently, we demonstrated that in rodents FasL mRNA is present in germ cells and not in Sertoli cells, and that FasL protein is displayed on the surface of spermatozoa. Here we propose that, for the mouse spermatozoa, the FasL may represent a self-defence mechanism against lymphocytes present in the female genital tract. To verify this hypothesis, we performed crossings between males gld, with nonfunctional FasL, and syngenic or nonsyngenic females. We observed a significant decrease of litter size in outbred crossings with gld males compared with wild-type males, suggesting a possible role of FasL in immunoprotection of the sperm in the female genital tract. The possibility that in humans, by analogy with mouse, FasL plays a self-protective role for the spermatozoon cannot be excluded, and awaits experimental information on the expression of FasL on human sperm cells.

Control and impairment of immune privilege in the testis and in semen

It has long been known that the testis is an immunologically privileged site in the body, and that human seminal plasma possesses a generalized immunosuppressive activity. Multiple factors participate in the establishment of immunotolerance in the testis: the blood-tubular barrier; the local production of immunosuppressive molecules by Sertoli cells; and the Fas system as regulator of immunological homeostasis in both physiological and pathological conditions. Cytokine-induced up-regulation of Fas as well as of integrin ligands, which are known to be specific binding molecules for lymphocytes on the Sertoli cell surface, indicates that the 'nursing' cells of seminiferous epithelium might be important in the impairment of immune privilege, causing autoimmune orchitis. In addition, the soluble form of Fas-ligand protein present in the seminal plasma of infertile patients might suggest a role for this immunomodulatory protein in male infertility. Finally, an understanding of the mechanisms underlying immune privilege in the testis and in semen might help to clarify how cells expressing 'non-self' antigens (such as male gametes) can escape the immune system in both the male and female genital tracts.

TNF-alpha induces surface modifications in mouse Sertoli cells: physiopathological implications

The expression of the adhesion molecules ICAM-1 and VCAM-1 has been measured in mouse Sertoli cells cultured in vitro. Cytometric analysis revealed that, in basal conditions, low levels of ICAM-1 and VCAM-1 were present on the surface of the cells, whereas treatment with TNF-alpha induced an increase in their expression. Binding experiments using both 51Cr-labelled lymphocytes, for quantitative analysis, and scanning electron microscopy demonstrated that increased expression of ICAM-1 and VCAM-1 on the surface of Sertoli cells, induced by TNF-alpha, determines an augmented adhesion between the two cell types. These results suggest the presence of a specific mechanism of interaction between Sertoli and immune-competent cells, possibly involved in the control of the immune response in the testis following an inflammatory reaction in situ. Such mechanism is of interest for the understanding of auto-immune pathologies of the testis and, if confirmed in humans, it could be involved in the sexual transmission of HIV infection.

Testicular FasL is expressed by sperm cells

The testis is the main source of Fas ligand (FasL) mRNA in rodents; it is generally believed that this molecule, expressed on bordering somatic Sertoli cells, bestows an immune-privileged status in the testis by eliminating infiltrating inflammatory Fas-bearing leukocytes. Our results demonstrate that the attribution of testicular expression of FasL to Sertoli cells is erroneous and that FasL transcription instead occurs in meiotic and postmeiotic germ cells, whereas the protein is only displayed on mature spermatozoa. These findings point to a significant role of the Fas system in the biology of mammalian reproduction.

[The megacolon in myotonic dystrophy: case report and review of the literature]

Myotonic dystrophy (MD) is an autosomal dominant inherit disease, slowly progressive, involving multiple organ systems. Disorders at any level of the gastrointestinal tract are relatively common and manifest as disturbances in motility, such as impaired esophageal transport, delayed gastric emptying, and megacolon. A 51 years-old man was admitted to our surgical department with obstructive symptoms. Diagnostic evaluation showed megacolon and the typical clinical features of the MD, such as weakness, myotonia, frontal baldness and testicular atrophy. Risk of perforation and dehydration led to emergency total colectomy with ileorectal stapled anastomosis. The patient didn't suffer for compliance related to surgical treatment but, after 1 month in intensive care, died of pneumonia and myocardial infarct. The overall frequency of perioperative complications in patients with MD ranges from 8.2 to 42.9%. The risk of perioperative pulmonary complications is particularly high. Thus, we believe that the conservative treatment of motility disorders of the bowel in patients with MD is to be justified and that surgical treatment should be reserved, as last resort, performing a early diagnosis and careful monitoring during perioperative period.

Platelet-derived growth factor-BB stimulates hypertrophy of peritubular smooth muscle cells from rat testis in primary cultures

The tunica propria of seminiferous tubules contains a particular type of smooth muscle cell (myoid cells) arranged in a contractile epithelioid layer that is responsible for sperm and tubular fluid flow. Unlike other types of smooth muscle (SM) cells, highly purified populations of peritubular smooth muscle cells (PSMC) survive and maintain their contractile phenotype in primary cultures in controlled conditions. We used this culture model to investigate the response of the SM contractile phenotype to prolonged exposure to platelet-derived growth factor (PDGF), one of the main factors involved in vascular SM pathologies. We observed that 4-day continuous exposure of PSMC to PDGF-BB at nanomolar concentrations in plain medium enhances contractile phenotype traits and induces cell hypertrophy without inducing proliferation. In Northern and Western blotting experiments, SM-alpha-actin transcript and protein were found to be markedly increased in the PDGF-BB-treated samples, which is in line with the formation of conspicuous SM-alpha-actin-containing stress fibers. Moreover, binding sites for endothelin-1 were increased, and the calcium response to the contractile agonist, determined in single fura-2-loaded cells, was enhanced. In response to PDGF-BB, the cells underwent immediate, transient contraction, as seen in a scanning electron microscope, followed by a gradual increase in size, as evaluated by cytofluorometry, and enhancement of protein synthesis. The observed pattern of response to PDGF-BB was not accompanied by cell proliferation, as assessed by [3H]thymidine incorporation and direct cell counts. Unlike other SM cell types, in which proliferation and loss of contractile traits are induced by PDGF, chronic treatment of PSMC with this growth factor results in hypertrophy rather than hyperplasia.

TNF-alpha and IFN-gamma regulate expression and function of the Fas system in the seminiferous epithelium

Sertoli cells have long been considered to be involved in the regulation of the immune response in the testis. More recently, the Fas system has been implicated in the maintenance of the immune privilege in the testis as well as in the regulation of germ cell apoptosis. However, the control of Fas and Fas ligand (FasL) expression in the testis remains unknown. In the present study, we demonstrate that cultured mouse Sertoli cells constitutively express a low level of membrane-bound Fas protein, but not a soluble form of Fas. Sertoli cells stimulated with TNF-alpha and IFN-gamma markedly increase the expression of both soluble and membrane-bound Fas in a dose-dependent manner. The up-regulated membrane-bound Fas protein is functionally active because it induces a significant level of Sertoli cell death in the presence of Neuro-2a FasL+ effector cells. Interestingly, the soluble form of Fas, which is induced by the same cytokines but has an antiapoptotic effect, is also functional. In fact, conditioned media from TNF-alpha-stimulated Sertoli cell cultures inhibit Neuro-2a FasL+-induced cell death. Taken together, our data suggest a possible regulatory role of TNF-alpha and IFN-gamma on Fas-mediated apoptosis in the testis through disruption of the balance between different forms of Fas.

Muscarinic receptors modulate intracellular calcium level in chick sensory neurons

In the present work we have studied the variation of intracellular calcium levels induced by muscarinic agonists in chick dorsal root ganglia neurons. Muscarinic agonists such as muscarine and oxotremorine cause an increase of intracellular calcium levels in fura-2AM-loaded DRG neurons of E18 chick embryos. This increase was abolished following treatment with 1 microM atropine but not by 1 microM mecamylamine, indicating that the observed intracellular calcium increase, was dependent on muscarinic receptor activation. Stimulation in absence of external calcium or pre-incubation of the DRG cultures with thapsigargin or Mn(2+) demonstrated that [Ca(2+)](i) increase is mainly due to its release from intracellular stores. The use of selective antagonists of muscarinic receptor subtypes also indicated that M(1) and to a lesser extent M(3) receptor subtypes are responsible for the observed intracellular calcium mobilization. Finally pre-treatment of DRG cultures with pertussis toxin showed that the variation of [Ca(2+)](i) levels was dependent on PTX-insensitive G-protein. Moreover muscarinic agonists induce in DRG also the increase of IPs level, suggesting that the variations of intracellular calcium levels may be due at least in part to the activation of the phosphoinositide transduction pathway. In conclusion the reported observations demonstrate the activity of muscarinic receptors in sensory neurons, suggesting a functional role for acetylcholine in sensory transduction.

[Scintigraphy with 99mTc-HMPAO-marked leukocytes and abdominal tumors: clinical interpretation of scintigraphy results]

The 99mTc-HMAPAO-labelled leucocyte scan is a widely employed diagnostic tool in the assessment of inflammatory and infective diseases. Nevertheless, leucocytes accumulation in neoplastic lesions has been reported. In the present study, aimed at the exploration of the abdomen and performed on 62 patients, positive scintigraphic findings were obtained in 66.6% (4/6) of the neoplasms and in 6.45% (4/62) of the studied cases. These scintigraphic results, even if they have to be considered as false positive cases, effectively reflect histopathologic changes present in the neoplastic tissue. On the basis of the obtained results, leucocytes accumulation in abdominal malignancies is probably due to the presence of necrosis and ulceration and to the resulting infection of the tumour.

Nerve-sparing surgery in rectal cancer: feasibility and functional results

Traditional rectal cancer surgery has been burdened with a high rate of sexual and urinary dysfunctions due to intraoperative injury or the cutting of the sympathetic and/or parasympathetic nerves. The experience acquired in the last ten years with total mesorectal excisions has permitted the use of the "nerve-sparing" technique. The present study regards 239 patients from two surgical centres, most of whom underwent sphincter-saving radical surgery between 1994 and 1998 with the above mentioned technique for resectable colon cancer. Details regarding the technique were recorded in the last 58 patients, in order to examine the severity of the surgical damage. The subgroup with the longest follow-up, which included 36 patients, was diagnostically evaluated by a surgeon, psychologist, urologist and neurologist to analyze the risk of sexual and urinary dysfunctions. A complete nerve-sparing was performed in 86.3% of the cases. The parasympathetic nerve trunks were those most often damaged because of perineural tumor spreading. Partial to complete sexual impotence was observed in 44% of the patients and surprisingly, preoperative dysfunctions were detected by means of the multidisciplinary approach in one third of these patients. Therefore, only 30.5% of the patients presented with strictly postoperative sexual impotency, above all, those who had undergone high-dose preoperative chemoradiation for T3 or T4 middle to low rectal cancer. A prospective study was initiated to evaluate the genitourinary dysfunctions after rectal cancer surgery in all of the clinical phases by means of a multidisciplinary approach aimed at functional recovery and improved quality of life.

Activation of Jun N-terminal kinase/stress-activated protein kinase pathway by tumor necrosis factor alpha leads to intercellular adhesion molecule-1 expression

Tumor necrosis factor alpha (TNF-alpha) is a cytokine implicated in the pathogenesis of numerous chronic and acute inflammatory conditions. We have previously shown that mouse Sertoli cells respond to TNF-alpha by increasing interleukin-6 production and intercellular adhesion molecule-1 (ICAM-1) expression (1). In this cell type TNF-alpha activates the mitogen-activated protein kinase (MAPK) pathways p42/p44 MAPK, JNK/SAPK, and p38, the last of which is responsible for interleukin-6 production (1). To determine which MAPK signaling pathway is required for TNF-alpha induction of ICAM-1 expression, we have utilized the protein kinase inhibitor dimethylaminopurine, demonstrating that treatment of Sertoli cells with such compound significantly reduced ICAM-1 expression and JNK/SAPK activation. Moreover, dimethylaminopurine treatment increased the expression of MAPK phosphatase-2, providing a possible mechanism of action of this compound. By using agonist antibodies to p55 and to p75 TNF-alpha receptors and both human and mouse TNF-alpha, we demonstrate that both TNF receptors are expressed and that only the p55 receptor is involved in ICAM-1 expression. The p55 receptor activates all of the three pathways, whereas p75 failed to activate any of the MAPKs. Altogether our results demonstrate that TNF-alpha up-regulates ICAM-1 expression through the activation of the JNK/SAPK transduction pathway mediated by the p55 receptor.

Is hyperdiploidy of immature ejaculated germ cells predictive of testis malignancy? A comparative study in healthy normozoospermic, infertile, and testis tumor suffering subjects

The possibility of diagnosing neoplastic testis pathologies by studying immature germ cells released from the seminiferous epithelium and present in the semen has been reported. It has been suggested that carcinoma in situ (CIS) of the testis and testis tumor may be identified by studying specific surface antigenic determinants or ploidy of chromosome 1 of malignant germ cells recovered from the semen. A noninvasive diagnostic approach of this type would be of great interest if we consider that CIS is supposed to precede the development of testicular germ cell tumors and that the frequency of that preneoplastic condition is increased in specific andrologic pathologies. To evaluate the reliability of this diagnostic approach, we have quantified the presence of immature hyperdiploid germ cells in the seminal fluid of normal healthy subjects, of infertile oligozoospermic patients affected by maldescended testis or left vancocele, and of patients suffering from CIS or testis tumor. Cell ploidy was evaluated on seminal cell fractions highly enriched in immature germ cells, by means of in situ hybridization with a DNA-probe specific for chromosome 1. Our observations indicate that chromosome 1 hyperdiploidy is not necessarily a predictive parameter of testis tumoral pathologies. The percentage of hyperdiploid immature seminal germ cells is in fact increased in nontumoral pathologies associated with infertility, such as cryptorchidism and left varicocele.

[Traditional cholecystectomy in a patient with situs viscerum inversus partialis]

The authors discuss the etiology of situs viscerum inversus partialis (SVIP), the associated anomalies and the malformations and the relative clinical problems, reviewing the international literature. The present a case of a 51 years old female with a diagnosis of umbilical hernia and cystocele. During hospitalization the patient complained a typical acute cholecystitis pain. The patient underwent ultrasonography, CT scan, and MNR that allowed us to diagnosis a calculous cholecystitis with SVIP and was elected for an open cholecystectomy. The Authors describe the surgical technique in relation to the anatomic anomalies, in particular vascular ones, that were discovered with the imaging studies and confirmed at laparotomy.

Cyclic expression of endothelin-converting enzyme-1 mediates the functional regulation of seminiferous tubule contraction

The potent smooth muscle agonist endothelin-1 (ET-1) is involved in the local control of seminiferous tubule contractility, which results in the forward propulsion of tubular fluid and spermatozoa, through its action on peritubular myoid cells. ET-1, known to be produced in the seminiferous epithelium by Sertoli cells, is derived from the inactive intermediate big endothelin-1 (big ET-1) through a specific cleavage operated by the endothelin-converting enzyme (ECE), a membrane-bound metalloprotease with ectoenzymatic activity. The data presented suggest that the timing of seminiferous tubule contractility is controlled locally by the cyclic interplay between different cell types. We have studied the expression of ECE by Sertoli cells and used myoid cell cultures and seminiferous tubule explants to monitor the biological activity of the enzymatic reaction product. Northern blot analysis showed that ECE-1 (and not ECE-2) is specifically expressed in Sertoli cells; competitive enzyme immunoassay of ET production showed that Sertoli cell monolayers are capable of cleaving big ET-1, an activity inhibited by the ECE inhibitor phosphoramidon. Microfluorimetric analysis of intracellular calcium mobilization in single cells showed that myoid cells do not respond to big endothelin, nor to Sertoli cell plain medium, but to the medium conditioned by Sertoli cells in the presence of big ET-1, resulting in cell contraction and desensitization to further ET-1 stimulation; in situ hybridization analysis shows regional differences in ECE expression, suggesting that pulsatile production of endothelin by Sertoli cells (at specific "stages" of the seminiferous epithelium) may regulate the cyclicity of tubular contraction; when viewed in a scanning electron microscope, segments of seminiferous tubules containing the specific stages characterized by high expression of ECE were observed to contract in response to big ET-1, whereas stages with low ECE expression remained virtually unaffected. These data indicate that endothelin-mediated spatiotemporal control of rhythmic tubular contractility might be operated by Sertoli cells through the cyclic expression of ECE-1, which is, in turn, dependent upon the timing of spermatogenesis.

Testicular germ cells of HIV-seropositive asymptomatic men are infected by the virus

In situ PCR hybridization studies in the testis of infected asymptomatic subjects detected the presence of HIV-1 proviral DNA in the nuclei of germ cells at all stages of differentiation suggesting that HIV-seropositive men produce infected spermatozoa that are released in the genital tract. In all subjects studied spermatogenesis was normal, the presence of provirus was not associated with germ cell damage and a very mild local immune response was observed. The HIV hybridization pattern observed in germ cells supports the hypothesis of a clonal infection. It is suggested the possibility of a direct infection of the germ cells by cell-free virus and that the testis might represent a site of early viral localization, well tolerated because of the immune privilege of this organ.

Tumor necrosis factor-alpha induces interleukin-6 production and integrin ligand expression by distinct transduction pathways

Tumor necrosis factor-alpha (TNF-alpha) is a pleiotropic cytokine that elicits a large number of biological effects. However, the intracellular signaling mechanisms that are responsible for the TNF-alpha effects remain largely unknown. We have previously demonstrated that cultured mouse Sertoli cells, after TNF-alpha treatment, increase the surface expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and interleukin-6 (IL-6) production (Riccioli, A., Filippini, A., De Cesaris, P., Barbacci, E., Stefanini, M., Starace, G., and Ziparo, E. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 5808-5812). Here, we show that, in cultured Sertoli cells, TNF-alpha activates the mitogen-activated protein kinase pathway (p38, c-Jun N-terminal protein kinase/stress-activated protein kinase, and the p42/p44 mitogen-activated protein kinases) as revealed by an increased phosphorylation of p38, activating transcription factor-2, c-Jun, and Elk-1. Furthermore, our data indicate that the biological effects induced by TNF-alpha in Sertoli cells (enhancement of ICAM-1, VCAM-1, and IL-6 expression) depend on the activation of different signaling pathways. SB203580, a highly specific p38 inhibitor, does not affect ICAM-1 and VCAM-1 expression, but strongly inhibits IL-6 production. Moreover, interferon-gamma, which up-regulates adhesion molecule expression and reduces IL-6 production, does not induce phosphorylation of p38. Our data strongly support the hypothesis that, in response to TNF-alpha, activation of p38 leads to IL-6 production, whereas ICAM-1 and VCAM-1 expression could be induced by activation of the c-Jun N-terminal protein kinase/stress-activated protein kinase pathway.

Contractile response of peritubular myoid cells to prostaglandin F2alpha

Prostaglandin (PG) F2alpha, a well known agonist of smooth muscle, is produced in the male gonad. We have investigated whether PG F2alpha stimulates seminiferous tubule contractility through direct action on peritubular myoid cells. Myoid cells from prepubertal rats were highly purified through Percoll density gradient and cultured in vitro. Stimulation with PG F2alpha was observed to induce: (i) rapid and dose-dependent production of inositol phosphates; (ii) mobilization of Ca2+ from intracellular stores and (iii) cell contraction. Moreover, at a concentration of 10 microM the agonist was found to induce immediate contractile response of peritubular tissue in freshly explanted tubular fragments from both young and adult rats; the explants were examined in whole-mount preparations and the peritubular myoid cell layer was identified by selective staining for alkaline phosphatase activity. Our observations demonstrate that myoid cells are a direct target for PG F2alpha and suggest a role of the eicosanoid in the intragonadal control of seminiferous tubule contractility.

Presence and cellular distribution of HIV in the testes of seropositive subjects: an evaluation by in situ PCR hybridization

Cellular distribution of HIV-1 proviral DNA has been studied, by in situ PCR hybridization, in the testes of infected men who died at various stages of the disease. In seropositive asymptomatic subjects, HIV-1 proviral DNA was present in the nuclei of germ cells at all stages of their differentiation. The presence of provirus did not induce germ cell damage, was associated with normal spermatogenesis, and was not accompanied by morphologic signs of immune response. The observed HIV hybridization pattern of germ cells suggests clonal infection. Mechanisms responsible for HIV penetration in testicular germ cells remain to be clarified; however, the possibility of a direct infection of the germ cells by cell-free virus is suggested. In the testes of AIDS-deceased men, histologic features of hypoplasia with arrested spermatogenesis were evident, and few infected spermatogonia and spermatocytes were observed. The whole of these data demonstrates that the testis is a site of early viral localization that fails to elicit an immunological response, and that HIV-seropositive men produce infected spermatozoa that are released in the genital tract.

Dual control of seminiferous tubule contractility mediated by ETA and ETB endothelin receptor subtypes

Testicular myoid cells surrounding the seminiferous tubule are contractile cells responsible for peritubular contractility and for the propulsion of tubular fluid and spermatozoa. We have investigated the contractile response of rat myoid cells to endothelins (ETs) in cell and organ culture and analyzed the cell signaling involved. ET-2, ET-3, and IRL 1620, a highly selective agonist of ETB receptor, elicit [Ca2+]i increases, though with dissimilar potencies and kinetics. Competition binding assays using [125I]ET-1, [125I]ET-3 and [125I]IRL 1620 show that myoid cells express both ETA and ETB receptors with high affinity for ET-1 and ET-1/ ET-3, respectively. All endothelin isoforms activate phosphoinositide (PI) turnover, but only stimulation of the ETA receptor mediates both PI turnover and mobilization of [Ca2+]i. Although stimulation of the ETB receptor with IRL 1620 fails to produce a significant effect on inositol phosphate (IP) production, it induces mobilization of a thapsigargin-sensitive intracellular Ca2+ pool in the absence of any measurable IP production. We also studied the effect of U-73122 [1-(6-[17-beta-3-methoxyestra-1,3,5 (10)-trien-17-yl] amino/hexyl)-1H-pirrole-2,5-dione] and its inactive analog, U-73343, on Ca2+ mobilization and IP production after selective stimulation of ET receptors. U-73122 (1 microM) completely inhibited the effect of ETA-mediated ET-1 stimulation of IP production, whereas U-73343 was inactive. However, in the presence of U-73122, the selective stimulation of ETB receptors induced the mobilization of a thapsigargin-sensitive and inositol phosphate-independent intracellular Ca2+ pool. The ETB receptor-dependent mobilization of [Ca2+]i resulted mainly from Ca2+ release from intracellular Ca2+ stores. This paper illustrates contraction of myoid cells in the seminiferous tubule in response to selective activation of either ET receptor. Scanning electron microscopy of the peritubular tissue demonstrates that the contractile response to ET was inhibited by a combination of BQ-123 and BQ-788, but not by either antagonist alone. Moreover, the observation that selective stimulation of ETB receptor with IRL 1620 also resulted in cell contraction strongly suggests that stimulation of either ETA or ETB receptors alone may be sufficient to elicit seminiferous tubule contractility. Two types of receptors account for the actions of endothelin on contractile activity of seminiferous tubule: 1) an ETA receptor that is positively coupled to phospholipase C (PLC) and Ca2+ mobilization; and 2) an ETB receptor that induces the mobilization of a thapsigargin-sensitive intracellular Ca2+ pool in a manner independent of the formation of inositol phosphates. ET may play a complex role in regulating the flux of spermatozoa along the seminiferous tubule through its contractile effect on peritubular myoid cells.

Direct visualization of rat peritubular myoid cell contraction in response to endothelin

Seminiferous tubule contractility is fundamental for sperm progression towards the rete testis; hence its regulation represents a key point in male fertility. Endothelin-1 (ET-1), a potent stimulator of smooth muscle contractility, has recently been shown to be produced in the testis, as well as to bind to specific receptors on myoid cells and thereby activate intracellular signaling. The present paper illustrates contraction of isolated myoid cells in response to ET-1 both in phase-contrast and scanning electron microscopy. Moreover, a simple method is described that allows visualization of a dramatic endothelin-induced rearrangement of myoid cell actin filaments in whole-mount preparations of seminiferous tubules. The response, which can be observed within seconds from stimulation, was paralleled by cell shape changes that were well apparent in scanning electron microscopy. The present report provides the first direct evidence that endothelin is an agonist of myoid cell contractility. Moreover, the experimental approach described could represent a promising tool for the screening of potential agonists of peritubular contractility and for the analysis of their mechanisms of action. In this regard, preliminary evidence is presented on myoid cell contractile response to [Arg8]-vasopressin.

Identification and characterization of an ecto-ATPase activity in rat Sertoli cells

A membrane associated extracellular ATPase (ecto) has been identified on rat Sertoli cells. Sertoli cell ecto-ATPase demonstrated a Km for ATP of 114 muM and a V(max) of 1.79 mumol/min/2 x 10(5) cells and was activated by either Mg2+ or Ca2+. This ecto-ATPase hydrolyzes other nucleoside triphosphates, but is inactive with ADP. The effects of some possible inhibitors of ectonucleotidases on the breakdown of extracellular ATP by Sertoli cells were also investigated.

[Injury of the popliteal artery & the popliteal branches: analysis of 31 consecutive cases]

In complex traumas of lower limbs it is fundamental the reducing of the time of ischemia to reduce the number of failures in repairing surgery and the percentage of the demolishing of necessity surgery. The experience of the authors is based on 31 complex traumas of lower limbs with distal vascular injuries to Hunter's canal, which were associated to bone, nervous and muscular lesions. In total we are treated 37 vascular injuries by interposition of venous autografts in 37 cases, lateral pacth in one case ant suture T-T in two cases. The protection of the reconstructed vases, in case of a concomitant loss of substance, was entrused to microvascular flaps for 7 times latissimus dorsi, iliac crest and fascio-cutaneous for 5 times posterior reversed with distal baset and for three times antero-lateral, which in three cases of them needed successively a dermoepidermic grafts. The bone injuries, which were treated by external fixation, intramedullary nailing, plate and screws, just in two cases became worse in pseudoarthroses and just in one in osteomyelitis. The reparation of nervous injuries had bad results just in two cases. The percentage of saving of the limb it was about 83.9%.

[Significance of antibiotic prophylaxis in infection prevention in biliary surgery. Personal experience]

Postoperative infections are one of the most frequent causes of morbidity in surgical patients. In biliary tract surgery the risk of septic complications is essentially increased by opening the bile ducts. Aim of this paper is to evaluate indications and effectiveness of short-term prophylaxis in preventing infective complications of biliary surgery. Authors report a personal six years review regarding 530 patients operated for biliary tract diseases. The patients were divided into two groups: the first one (n. 245) operated under short-term prophylaxis; the second one (n. 285) treated only postoperativelly with antibiotics. The results obtained show a significatively higher rate of infective complications in the second group of patients. There is a little difference between the groups in the case of elective cholecystectomy, whereas there is a great difference in case of non-elective surgery, bile ducts opening, external biliary drainages placement or sphincteropapillotomy. Authors furthermore emphasize how surgical results are conditioned by individual risk factors, especially obesity and diabetes.

[The distal pedicle fasciocutaneous flaps of the leg. Analysis of 21 cases of lower limb reconstruction]

The fascio-cutaneous flaps with distal pedicle, with the new discoveries on fascial and septal circulation of the lower limbs, are a valid reconstructing method for the loss of substance localized on the third inferior of the leg and in the heel's region. In 21 patients, 18 men and 3 women, fascio-cutaneous flaps were employed for the traumatic loss of substance, just in two cases consequentially to removal of maligns lesions, all of them were omolaterals except in three cases in which cross-leg were used. The results are satisfying if we remember that just in two cases we had partial necrosis and in other two cases we had to reinstate the flap which had survived just in his deep position. The advantages of using this technique are supported by his good results and simple execution, realising anyhow that complicated or contaminated trumas need more complex plastic reconstruction.

Inflammatory mediators increase surface expression of integrin ligands, adhesion to lymphocytes, and secretion of interleukin 6 in mouse Sertoli cells

The expression of the cell adhesion molecules ICAM-1, ICAM-2, and VCAM-1 and the secretion of the cytokine interleukin 6 have been measured in mouse Sertoli cells cultured in vitro. Cytometric analysis revealed that, in basal conditions, low levels of ICAM-1 and VCAM-1 were present on the surface of the cells, whereas treatment with interleukin 1, tumor necrosis factor alpha, lipopolysaccharide, or interferon gamma induced, with different kinetics, increases in their expression. ICAM-2 was not detectable in basal conditions, nor was it inducible. Electron microscopic analysis and binding experiments using 51Cr-labeled lymphocytes demonstrated that increased expression of ICAM-1 and VCAM-1 on the surface of Sertoli cells, induced by inflammatory mediators, determines an augmented adhesion between the two cell types. The same stimuli, with the exception of interferon gamma, produced a rapid and remarkable increment of interleukin 6 production by Sertoli cells. These results suggest the presence of both direct and paracrine mechanisms of interaction between Sertoli and immune-competent cells, possibly involved in the control of immune reactions in the testis. Such mechanisms are of interest for the understanding of autoimmune pathologies of the testis and, if confirmed in humans, they could be involved in the sexual transmission of human immunodeficiency virus infection.

[The biological effects of the CO2 laser studied in experimental intestinal resections]

An histological and E.M. study has been performed on rat's intestinal tract resection to evaluate CO2 laser effects. Necrotic effect of laser is evident up to 120 micron. While the intestinal tissue results normal at 480 micron from resection line. Muscular and fibrous components appear more resistant to damage while E.M. presents a new organization of its components forming a new compact and continue tissue. This new organization may be involved in the protection of the subepithelial spaces, and may have an important role in intestinal anastomosis scar process.

[A specific technique for ileo-anal anastomosis in restorative proctocolectomy: physiopathological evaluation and results]

The Authors report an alternative technique for ileo-anal anastomosis in total proctocolectomy with ileal pouch. Their experience and results are discussed.

[A histological and ultrastructural study of the effects of the argon laser scalpel on the kidney]

The authors carried an histological and ultrastructural study on rat kidney following polar excision by argon laser. The involvement of the remainder portion of the kidney was evaluated analysing the depth of the damage induced by the laser radiation. Restitution ad integrum was found below 360 micron thickness with a different involvement of the various kidney components. Glomeruli showed a deep damage caused by intravascular photocoagulation. On the contrary, tubular and extracellular damage was less serious and the damaged area extended for only 240 micron from the section, probably for a lack of absorbance of the argon radiation by clear and water-rich tissues.

Activation of inositol phospholipid turnover and calcium signaling in rat Sertoli cells by P2-purinergic receptors: modulation of follicle-stimulating hormone responses

To study the role of extracellular nucleotides in the regulation of Sertoli cells, the effects of ATP and its analogs on the Ca(2+)-phospholipid- and cAMP-dependent pathways were tested. Cultured Sertoli cells from immature animals were incubated with ATP or structurally related compounds, and phosphoinositide (PI) turnover or cAMP accumulation was measured. Among the several nucleotide phosphate analogs tested, adenosine 5'-O-(3-thiotriphosphate) was the agonist most potent in stimulating inositol phosphate accumulation. The effects of purine nucleotides on PI turnover were time and concentration dependent. Because nonhydrolizable ATP analogs also stimulated PI turnover, ATP metabolites or metabolic products are not responsible for the observed stimulation. The order of potency of the different ATP analogs [adenosine 5'-O-(3-thiotriphosphate) > ATP approximately equal to UTP > beta, gamma-methyleneadenosine 5'-triphosphate, 2-methylthio-ATP > adenosine] was consistent with the presence of P2U receptors (nucleotide receptors) on the surface of the Sertoli cell. Augmented PI turnover was accompanied by a transient increase in Ca2+ concentration, measured in single Sertoli cells loaded with the intracellular Ca2+ indicator fura-2. When used alone, ATP and its analogs did not have a direct effect on cAMP levels in the Sertoli cell. However, ATP or its analogs inhibited FSH-dependent cAMP accumulation by more than 70%. Purine nucleotides also efficiently blocked the effects of FSH distal to cAMP accumulation, because extracellular ATP completely reversed the changes in Sertoli cell shape induced by FSH. The nucleotide-dependent inhibition of cAMP accumulation was blocked by pertussis toxin to a different degree depending on the purine or pirimidine nucleotide used. This indicated that more than one mechanism contributes to the purine nucleotide-dependent inhibition of cAMP accumulation. These data provide evidence that purine nucleotide receptors coupled to multiple pathways are present on the Sertoli cell in culture, and that extracellular ATP has profound biological effects on the FSH responsiveness of the Sertoli cell.

Advances in rectal cancer surgery

PURPOSE

We discuss our experience in radical rectal cancer surgery and critically review the results of the current literature. In particular, the importance of distal clearance, total excision of the mesorectum, and pelvic lymphadenectomy is stressed.

METHODS AND RESULTS

The rationale for determining a pelvic lymphadenectomy is identified in the high percentage (20 percent) of lateral endopelvic metastatic nodes demonstrated in cases of extraperitoneal rectal cancers. The results after pelvic lymphadenectomy and the eventual complications are observed. The autonomic nerve-sparing procedure is described and the preliminary results, with a decreased rate of urinary and sexual sequelae, are discussed.

CONCLUSIONS

It was concluded that, in cases of an advanced rectal cancer, radical surgery, if associated with the nerve-sparing technique, can improve survival without affecting the incidence of major complications.

Rat testicular myoid cells respond to endothelin: characterization of binding and signal transduction pathway

The presence of endothelin (ET), a vasoconstrictor peptide, in the testis suggests that it may regulate nonvascular target cells. We investigated binding ability, regulation of inositol phosphate metabolism, changes in cytosolic free Ca2+ concentrations ([Ca2+]i), and induction of morphological changes by ET-1 in rat primary testicular myoid cell cultures. ET-1 specifically bound to highly purified rat testicular myoid cells in a time- and temperature-dependent manner. Scatchard analysis of the binding studies indicated the presence of a single class of high affinity binding sites, with an apparent Kd of 3 x 10(-10) M and a maximal binding capacity of 10(5) sites/cell. ET-1 induced both rapid production of inositol triphosphate and mobilization of [Ca2+]i in a concentration-dependent fashion. By contrast, inositol lipid metabolism was slightly affected by ET-1 in the total peritubular cell population. Purified Sertoli cells failed to show either ET-1 binding or ET-1-induced phosphatidylinositol hydrolysis. Mobilization of [Ca2+]i mostly depended upon the release of Ca2+ from thapsigargin-sensitive intracellular Ca2+, whereas it was not affected by abolishment of the Ca2+ gradient through the plasma membrane or by inhibition of L-type voltage-sensitive Ca(2+)-channels by nifedipine. These findings together with the fact that Sertoli cells are unable to respond to and bind ET-1 indicate that ET is a specific agonist of myoid cells in the seminiferous tubule and suggest a role for ET-1 in the autocrine/paracrine regulation of testicular function.

[The role of echography in the determination and monitoring of ductal ectasia in nipple discharge]

In this study a good sensibility of ultrasound in identifying ductal disease was demonstrated. We evaluated the relationship between nipple discharge and ductal ectasia and the importance of the ectasia in maintaining nipple discharge. From our data the hypothesis of a possible role of oestroprogestinic hormones in the genesis or maintaining of ductal ectasia emerged.

[Malignant fibrous histiocytoma of the pancreas]

The authors report a case of pancreatic malignant fibrous histiocytoma (approximately 22 cm). Clinical and instrumental approach for preoperative diagnosis is discussed and the anatomopathological features of the lesion, which is rarely localized in the pancreatic gland, are stressed. Surgical treatment is outlined as well.

Immunosuppressive molecules produced by Sertoli cells cultured in vitro: biological effects on lymphocytes

In the present study we have analyzed the proteins secreted in vitro by murine Sertoli cells to identify immunosuppressive factors. Our data show that Sertoli cells secrete molecules capable to inhibit proliferation of lymphocytes activated in vitro. Cytophluorimetric analysis indicates that treated cells are arrested in the G1 phase of cell cycle. The inhibitory activity is specific for both B or T lymphocytes but not for other non-lymphoid cells and is associated to proteins, heat and freeze stable, with Mr of more than 30 kDa. Lymphocytes treated with Sertoli immunosuppressive proteins drastically reduce the secretion of interleukin-2.

[Diagnosis, prognosis and therapy of phyllodes tumor of the breast]

The Authors report 4 cases very interesting for the differential diagnosis of phyllodes tumor, a breast tumor with a mainly local malignant potential. Such tumor, although presenting histologic, clinical and instrumental features which allow for a presumptive pre-surgical diagnosis, often has characteristics comparable to other breast pathologies with a different natural history. The Authors, after analyzing clinical, mammographic, echographic and histologic features of the tumor, suggest the most appropriate therapy for the local control of the lesion. Surgical excision should be carried at least 1 cm deep into the normal tissue to prevent local relapse related to an incomplete enucleation: in fact, the tumor is only apparently capsulated. Furthermore, the Authors believe a patients must undergo, after primary surgery, an adequate instrumental and clinical follow up for the early diagnosis of commonly occurring relapses.

Steroid-dependent form of Kinsbourne syndrome: successful treatment with trazodone

We report the case of a 19 month old girl with myoclonic encephalopathy of infants (MEI) (Kinsbourne syndrome), on long-term therapy with ACTH for the occurrence of frequent relapses (steroid-dependent form). The administration of trazodone per os at low doses as an alternative to the previous treatment ensured complete remission, also on the occasion of a subsequent relapse. No rebound effects were observed after trazodone withdrawal (10 months). At present, 3 years after withdrawal of the therapy, the child is well and free from symptoms. The hypothesis that trazodone may be effective in treating MEI, at least in cases that are steroid-dependent or resistant to ACTH, appears highly interesting. Trazodone is proposed as a possible alternative to treatment with ACTH.

Comparative studies of the cytotoxic T lymphocyte-mediated cytotoxicity and of extracellular ATP-induced cell lysis. Different requirements in extracellular Mg2+ and pH

We recently proposed that extracellular ATP (ATPo) may be involved in CTL-mediated cytotoxicity by acting in concert with yet unidentified cellular components (ATPo receptors/ATPo-binding proteins, ectoprotein kinases). The TCR-triggered ATPo accumulation by CTL has been demonstrated, whereas the resistance of CTL to ATPo was explained by the action of highly active ecto-ATPases or by the absence of relevant ATP-binding proteins. However, no data were available to discriminate between the possibilities of: i) ATPo acting alone as a "hit" molecule because of the cell-permeabilizing properties of ATP4- or ii) ATPo acting as a "messenger" (as MgATP2-) in concert with other molecules. Comparing ATPo-induced and CTL-mediated cell lysis, we found that ATPo-induced lysis of some target cells is greatly decreased at neutral and acidic pH, whereas Ca(2+)-dependent CTL-mediated lysis of the same cells is barely affected. In agreement with the observed pH dependency, at low Mg2+ concentrations, which favor ATP4- over MgATP2-, maximal ATPo-induced lysis was observed. However, CTL-mediated cytotoxicity in both Ag-specific and retargeting assays was markedly reduced at low Mg2+ concentrations. These results suggest that ATPo acting alone as a "hit" molecule cannot fully account for the extracellular Ca(2+)-dependent lethal hit delivery by CTL or that ATP4- is active at very low concentrations. This conclusion was further supported by studying the lytic effect of ATPo and CTL on the anti-TCR mAb-coupled SRBC. CTL were efficient in the SRBC lysis, whereas no lysis of SRBC by ATPo was detected. The resistance of SRBC to ATPo is not caused by a high ATPo degradation, because the ecto-ATPase activity of SRBC was much lower than in ATPo-resistant CTL OE4 cells and comparable with EL4 tumor cells, which were easily lysed by ATPo. These data suggested the need for careful consideration of the pH and cation composition of the media used for studying ATPo effects. The caveats in the use of ATP-degrading enzymes to implicate the role of extracellular ATPo in the CTL-mediated cytotoxicity are described here. A clarification of the previously described cytotoxicity inhibition by hexokinase, which is caused by an inhibitory salt effect, is presented. It is suggested that if Ca(2+)-dependent lysis of SRBC and of other target cells by CTL does involve extracellular ATP, it may function as a "messenger" in concert with other extracellular molecules.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparative studies of the cytotoxic T lymphocyte-mediated cytotoxicity and of extracellular ATP-induced cell lysis. Different requirements in extracellular Mg2+ and pH

We recently proposed that extracellular ATP (ATPo) may be involved in CTL-mediated cytotoxicity by acting in concert with yet unidentified cellular components (ATPo receptors/ATPo-binding proteins, ectoprotein kinases). The TCR-triggered ATPo accumulation by CTL has been demonstrated, whereas the resistance of CTL to ATPo was explained by the action of highly active ecto-ATPases or by the absence of relevant ATP-binding proteins. However, no data were available to discriminate between the possibilities of: i) ATPo acting alone as a "hit" molecule because of the cell-permeabilizing properties of ATP4- or ii) ATPo acting as a "messenger" (as MgATP2-) in concert with other molecules. Comparing ATPo-induced and CTL-mediated cell lysis, we found that ATPo-induced lysis of some target cells is greatly decreased at neutral and acidic pH, whereas Ca(2+)-dependent CTL-mediated lysis of the same cells is barely affected. In agreement with the observed pH dependency, at low Mg2+ concentrations, which favor ATP4- over MgATP2-, maximal ATPo-induced lysis was observed. However, CTL-mediated cytotoxicity in both Ag-specific and retargeting assays was markedly reduced at low Mg2+ concentrations. These results suggest that ATPo acting alone as a "hit" molecule cannot fully account for the extracellular Ca(2+)-dependent lethal hit delivery by CTL or that ATP4- is active at very low concentrations. This conclusion was further supported by studying the lytic effect of ATPo and CTL on the anti-TCR mAb-coupled SRBC. CTL were efficient in the SRBC lysis, whereas no lysis of SRBC by ATPo was detected. The resistance of SRBC to ATPo is not caused by a high ATPo degradation, because the ecto-ATPase activity of SRBC was much lower than in ATPo-resistant CTL OE4 cells and comparable with EL4 tumor cells, which were easily lysed by ATPo. These data suggested the need for careful consideration of the pH and cation composition of the media used for studying ATPo effects. The caveats in the use of ATP-degrading enzymes to implicate the role of extracellular ATPo in the CTL-mediated cytotoxicity are described here. A clarification of the previously described cytotoxicity inhibition by hexokinase, which is caused by an inhibitory salt effect, is presented. It is suggested that if Ca(2+)-dependent lysis of SRBC and of other target cells by CTL does involve extracellular ATP, it may function as a "messenger" in concert with other extracellular molecules.(ABSTRACT TRUNCATED AT 400 WORDS)

[Angiolymphoid hyperplasia with eosinophilia (Kimura's disease): an unusual pathology]

The authors report a case of Kimura's disease recently observed. Diagnostic problems related to this rare pathologic condition as well as current and most reliable etiopathogenetic hypothesis are emphasized. Histopathological and clinical features are described in detail.

[Free microvascularized flaps in head and neck lesions: the technics of microsurgical reconstruction]

The authors report their experience of microsurgical reconstructive techniques using musculo-cutaneous free flaps after radical operations for head and neck neoplasms.

Extracellular ATP in T-lymphocyte activation: possible role in effector functions

We hypothesized that cytolytic T lymphocytes (CTL) may utilize extracellular ATP (ATPo) during the effector phase of the CTL-target cell interactions and that CTL could be the source of ATPo. It is demonstrated here that incubation of CTL with activating ligands [Con A or monoclonal antibody (mAb) to the T-cell antigen receptor (TCR)] results in the extracellular Ca2(+)-independent accumulation of the ATPo. The addition of the ATP-degrading enzymes into the mixture of CTL and target cells results in a strong inhibition of the CTL-mediated, TCR-triggered lethal-hit delivery to the target cell. In a parallel control experiment, the employed enzymes did not affect target cell-induced, TCR-triggered exocytosis of granules from CTL. Thus, the removal of ATPo with enzymes does not interfere with the activation of CTL by the target cell but does block lytic events. Cloned helper T lymphocytes also accumulate ATPo after incubation with anti-TCR mAb or Con A, suggesting the possibility that ATPo, which acts in concert with ectoprotein kinases and/or purinergic receptors, may be of general use as a messenger in cellular interactions of T lymphocytes.

[A case of carcinoma of the cervical esophagus treated with interposition of an intestinal loop revascularized using a microsurgical technique]

The Authors present a case of hypopharyngeal tumor in which digestive continuity was assured by a jejunal autotransplant. Tumoral exeresis and jejunal preparation were carried out at the same time by two surgical teams. The use of microsurgical techniques assures the revascularization of the neck transplant by implementing the superior thyroid artery and the internal jugular vein. Digestive anastomoses complete the operation.

[Role of microsurgery in chronic distal obstructive arteriopathies]

The Authors analyze the role of microsurgery in the treatment of chronic obstructive arteriopathies. In accordance with their results, they stress the usefulness of the microtechniques in the rescue of ischaemic limbs due to distal occlusion, and how these procedures are less dangerous than amputation, even though results are not long lasting.

[Venous grafts in reimplantation of the thumb]

The Authors analyze their experience of 25 thumb reimplantations and revascularizations within 5 years. The importance of the first finger in the functional hand economy as well as the ratio between reimplantation take rate and degree of functional recovery with regard to the type of trauma, technique used, and possible and incidental complications are underlined. The venous autologous grafts are of great importance in this microsurgical area and they are more and more applied. In most cases, indeed, intimal lesions are more extended than their macroscopic appearance and the tract of damaged vessels is always wider than assessed. The graft interposition solves the problem with the further advantage to preserve the maximal bone length and to avoid especially contaminated areas. The results achieved confirm these statements and the Authors conclude for the absolute need of venous grafts in thumb reimplantations, especially after amputation from avulsion or crush traumas, even though a greater skill is necessary in using this technique.