Treatment of unstable spinopelvic fractures: outcome of three surgical techniques-a retrospective single-center case series.

PURPOSE: The aim of our retrospective study is to analyze how spinopelvic dissociations (SPDs) were treated in a single center trying to better understand how to improve surgical and non-surgical options. METHODS: Twenty patients of a single center surgically treated for SPDs between 2013 and 2021 were retrospectively included in this study. Three surgical techniques have been used: modified triangular stabilization, triangular stabilization and double iliac screws stabilization. Follow-up was assessed for up to 11.6 ± 9.9 months through ODI, MRS, NRS, IIEF or FSFI, a CT scan and whole spine X-ray examination. RESULTS: Twenty patients were admitted to our ER for traumatic spinopelvic dissociation. Surgical treatment for spinopelvic dissociation has been performed on average 11.5 ± 6.7 days after the trauma event. Eighteen fractures were C3 type and two C2 types. Neurological examination showed nerve root injury (N2) in 5 patients, incomplete spinal cord injury (N3) in 4 patients and cauda equina syndrome in two patients (N4). In case of neurologic deficits, routinary nerve decompression was performed. Three different surgical techniques have been used: 8 triangular fixations (Group 1), 6 modified triangular stabilization (Group 2) and 6 double iliac screws triangular fixation (Group 3). CONCLUSION: In patients with post-traumatic neurological deficit, decompression surgery and fracture reduction seem to be associated with clinical improvement; however, sexual disorders seem to be less responsive to the treatment. Some open stabilization techniques, such as the double iliac screw, could help in restoring the sagittal balance in case of severe deformities.

A Bodipy as a luminescent probe for detection of the G protein estrogen receptor (GPER).

We report the rational design, based on docking simulations, and synthesis of the first fluorescent and selective probe of GPER for bioimaging purposes and functional dissecting studies. It has been conceived as a Bodipy derivative and obtained by accessible and direct synthesis. Its optical properties have been measured in different solvents, showing insensitivity to their polarity. Its binding to GPER was achieved by competition assays with [3H]E2 and [5,6-3H] nicotinic acid in ER-negative and GPER-positive SkBr3 breast cancer cells. SkBr3 cells, transfected with a GPER expression vector containing a FLAG tag, were used to confirm that the fluorophore binds to GPER in a specific manner.

Synergism between asymmetric dimethylarginine (ADMA) and a genetic marker of uric acid in CKD progression.

BACKGROUND & AIMS: We have recently reported that a polymorphism (rs734553) in a major urate transporter gene (GLUT9) is a strong predictor of incident renal events in stage 2-5 CKD patients implying that life-time exposure to high uric acid levels may be causally implicated in CKD progression. Since disturbed NO bioavailability is a major pathway whereby high uric may cause renal damage, we tested the interaction between the major endogenous inhibitor of NO synthase, asymmetric-dimethylargine (ADMA), and the rs734553 polymorphism for CKD progression in the same cohort. METHODS & RESULTS: Over a 29 ± 11 months follow-up the risk for incident renal events was higher in patients harboring the risk allele of the polymorphism (T) as compared to those without the risk allele (HR: 2.35, 95% CI: 1.25-4.42, P = 0.008) (p = 0.01). Similarly, patients with ADMA > median value had an increased risk for the same outcome (HR: 1.37, 95% CI: 1.06-1.76, P = 0.016). Interaction analysis showed a strong amplification by ADMA of the risk for renal events associated to the T allele because in adjusted (P = 0.016) and bootstrapping validated (P = 0.020) analyses the risk excess associated to this allele was progressively higher across increasing ADMA levels. CONCLUSIONS: The rs734553 polymorphism, the strongest genetic marker of uric acid levels discovered so far, interacts with ADMA in determining the risk for CKD progression in CKD patients. This synergic interaction conforms to biological knowledge indicating that disturbed NO bio-availability is a critical pathway whereby life time exposure to high uric acid may engender renal damage.

Pro- and anti-inflammatory cytokine gene expression in subcutaneous and visceral fat in severe obesity.

BACKGROUND AND AIMS: Pro-inflammatory molecules produced by adipose tissue have been implicated in the risk of cardiovascular (CV) disease in obesity. We investigated the expression profile of 19 pro-inflammatory and seven anti-inflammatory genes in subcutaneous adipose tissue (SAT) and in visceral adipose tissue (VAT) in 44 severely obese individuals who underwent bariatric surgery. METHODS AND RESULTS: SAT and VAT expressed an identical series of pro-inflammatory genes. Among these genes, 12 were significantly more expressed in SAT than in VAT while just one (IL18) was more expressed in VAT. The remaining genes were equally expressed. Among pro-inflammatory cytokines, both IL6 and IL8 were about 20 times more intensively expressed in SAT than in VAT. The expression of nine genes was highly associated in SAT and VAT. Only for three pro-inflammatory cytokines (IL8, IL18, SAA1) in SAT the gene expression in adipose tissue associated with the circulating levels of the corresponding gene products while no such an association was found as for VAT. CONCLUSIONS: The expression of critical pro-inflammatory genes is substantially higher in SAT than in VAT in individuals with morbid obesity. The variability in circulating levels of pro-inflammatory cytokines is, in small part and just for three pro-inflammatory cytokines, explained by underlying gene expression in SAT but not in VAT. These results point to a compartment-specific adipose tissue contribution to inflammation in obesity and indicate that abdominal SAT contributes more than VAT to the pro-inflammatory milieu associated with severe obesity.

Plasma cytokines, glomerular filtration rate and adipose tissue cytokines gene expression in chronic kidney disease (CKD) patients.

BACKGROUND AND AIM: Systemic inflammation is a hallmark of chronic kidney disease (CKD) and obesity represents a major risk factor for CKD. We investigated the relationship between plasma interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α) and the glomerular filtration rate (GFR) in 75 stage 2-5 CKD patients. METHODS AND RESULTS: We studied the steady-state relationship between plasma and subcutaneous adipose tissue (SAT) gene expression of the same cytokines in 19 patients and in 17 well-matched healthy subjects (HS) and compared SAT gene expression of these cytokines and of two additional cytokines (IL-1ß and IL-8) in CKD patients and in HS. Plasma IL-6 and TNF-α were higher in CKD patients than in HS (P < 0.001). IL-6 was similarly increased in patients with mild, moderate and severe CKD and largely independent of the GFR (r = -0.03, P = NS). TNF-α was inversely related to GFR, which was the first factor in rank (ß = -0.37, P = 0.001) explaining the variability in TNF-α in CKD. SAT messenger RNA (mRNA) levels of IL-6, TNF-α, IL- ß and IL-8 were similar in CKD patients and in HS. Plasma and SAT mRNA levels of IL-6 and TNF-α levels were largely unrelated. CONCLUSIONS: Plasma IL-6 rises early in CKD and does not show any further increase at more severe stages of CKD, whereas TNF-α is inversely associated with the GFR indicating a substantial difference in the dynamics of the relationship between these cytokines and renal function. Cytokines are not overexpressed in SAT in these patients, and circulating IL-6 and TNF-α are dissociated from the corresponding mRNA levels in SAT, both in CKD patients and in HS.

Psychiatric symptoms and quality of life in systemic sclerosis.

INTRODUCTION: Systemic sclerosis (SSc) is a rare conjunctive tissue disorder characterized by fibrosis of the skin and internal organs, and vascular obliteration phenomena. Patients with SSc often experience elevated symptoms of psychological distress, determined by the disfiguration, the pain, the fatigue sensation, and the difficult in daily life occupations. The characteristics of the disease may influence the perceived quality of life (QoL) in people with SSc. METHODS: This is a narrative review aiming to define the amount of impairment of Quality of Life in patients with Systemic Sclerosis and the component of this impairment due to depressive or other psychiatric symptoms. The search of the significant articles was carried out in PubMed for the key words "Psychiatric symptoms and Systemic Sclerosis"; "Quality of life and Systemic Sclerosis"; "Depressive Disorders and Systemic Sclerosis". RESULTS: Psychiatric symptoms are frequents in patients with SSc, but pain, fatigue, disability, body changes don't appear to explain the high prevalence of psychiatric comorbidity in SSc. Many studies founded a significant impairment in SSc patients' QoL, and despite the undeniable correlation between physical symptoms and SSc patients' QoL, mental health was found significantly impaired. DISCUSSION: The high rate of depression seems to strictly correlate with poor quality of life, and this finding needs more research to establish the cause of such a correlation. Patients' point of view regarding their health-related QoL could help physicians to enlarge the knowledge about physical and mental correlates of the disease, and to fit therapies as patient required. Particular attention must be given to provide the patient with correct information, in order to mitigate the anxious state on disease course, and to enhance coping skills of the patients.

Limit analysis of human proximal femur.

A limit analysis numerical approach oriented to predict the peak/collapse load of human proximal femur, under two different loading conditions, is presented. A yield criterion of Tsai-Hu-type, expressed in principal stress space, is used to model the orthotropic bone tissues. A simplified human femur 3D model is envisaged to carry on numerical simulation of in-vitro tests borrowed from the relevant literature and to reproduce their findings. A critical discussion, together with possible future developments, is presented.

Breakdown of species boundaries in Mandevilla: floral morphological intermediacy, novel fragrances and asymmetric pollen flow.

Phenotypic intermediacy is an indicator of putative hybrid origin and has provided the main clues to discovering hybrid plants in nature. Mandevilla pentlandiana and M. laxa (Apocynaceae) are sister species with clear differences in floral phenotype and associated pollinator guilds: diurnal Hymenoptera and nocturnal hawkmoths, respectively. The presence of individuals with intermediate phenotypes in a wild population raises questions about the roles of visual and olfactory signals (i.e. corolla morphology and floral fragrances) as barriers to interbreeding, and how the breakdown of floral isolation occurs. We examined phenotypic variation in a mixed Mandevilla population, analysing the chemical composition of floral fragrances, characterising floral shape through geometric morphometrics and assessing individual grouping through taxonomically relevant traits and an unsupervised learning algorithm. We quantified the visitation frequencies of floral visitors and tracked their foraging movements using pollen analogues. The presence of morphologically intermediate individuals and pollen analogue movement suggested extensive hybridisation between M. laxa and M. pentlandiana, along with asymmetrical rates of backcrossing between these putative hybrids and M. laxa. Floral volatiles from putative hybrid individuals showed a transgressive phenotype, with additional compounds not emitted by either parental species. Our results suggest the presence of a hybrid swarm between sympatric M. pentlandiana and M. laxa and indicate that initial hybridisation events between these parental species are rare, but once they occur, visits between putative hybrids and M. laxa are common and facilitate continued introgression.

Cerebral Mitochondrial Microangiopathy Leads to Leukoencephalopathy in Mitochondrial Neurogastrointestinal Encephalopathy.

BACKGROUND AND PURPOSE: Mitochondrial neurogastrointestinal encephalopathy is a rare disorder due to recessive mutations in the thymidine phosphorylase gene, encoding thymidine phosphorylase protein required for mitochondrial DNA replication. Clinical manifestations include gastrointestinal dysmotility and diffuse asymptomatic leukoencephalopathy. This study aimed to elucidate the mechanisms underlying brain leukoencephalopathy in patients with mitochondrial neurogastrointestinal encephalopathy by correlating multimodal neuroradiologic features to postmortem pathology. MATERIALS AND METHODS: Seven patients underwent brain MR imaging, including single-voxel proton MR spectroscopy and diffusion imaging. Absolute concentrations of metabolites calculated by acquiring unsuppressed water spectra at multiple TEs, along with diffusion metrics based on the tensor model, were compared with those of healthy controls using unpaired t tests in multiple white matters regions. Brain postmortem histologic, immunohistochemical, and molecular analyses were performed in 1 patient. RESULTS: All patients showed bilateral and nearly symmetric cerebral white matter hyperintensities on T2-weighted images, extending to the cerebellar white matter and brain stem in 4. White matter, N-acetylaspartate, creatine, and choline concentrations were significantly reduced compared with those in controls, with a prominent increase in the radial water diffusivity component. At postmortem examination, severe fibrosis of brain vessel smooth muscle was evident, along with mitochondrial DNA replication depletion in brain and vascular smooth-muscle and endothelial cells, without neuronal loss, myelin damage, or gliosis. Prominent periependymal cytochrome C oxidase deficiency was also observed. CONCLUSIONS: Vascular functional and histologic alterations account for leukoencephalopathy in mitochondrial neurogastrointestinal encephalopathy. Thymidine toxicity and mitochondrial DNA replication depletion may induce microangiopathy and blood-brain-barrier dysfunction, leading to increased water content in the white matter. Periependymal cytochrome C oxidase deficiency could explain prominent periventricular impairment.

Carbon Modular Orthosis (Ca.M.O.): An innovative hybrid modular ankle-foot orthosis to tune the variable rehabilitation needs in hemiplegic cerebral palsy.

BACKGROUND: Hemiplegic Celebral Palsy (CP) children commonly use AFO orthoses as walking aids. It is known that AFOs may have a detrimental effect on gait. To enhance mechanical properties of AFOs we developed an innovative, custom-made, carbon, ankle-foot orthosis (Ca.M.O) which offers the opportunity to tune its response to the patient's gait characteristics and/or functional maturity. OBJECTIVE: To assess the efficacy of Ca.M.O. in improving gait in a group of hemiplegic CP children and to compare its performances with those of commonly prescribed AFO. METHODS: A clinical and instrumental gait analysis was performed on a group of 15 spastic hemiplegic children (WINTERS-GAGE type I-II) walking barefoot, with commonly prescribed AFOs and with Ca.M.O.Temporal, kinematic and kinetic data were collected with an 8 cameras optoelectronic system and 2 force plates. RESULTS: Studied variables were comparable walking with Ca.M.O. and with the commonly prescribed AFO and are significantly different (p < 0.01) with respect to barefoot condition. CONCLUSIONS: Both types of orthoses normalize the kinematics of the first and second ankle rocker. The main advantage of Ca.M.O. is its modularity that allows to tune its effect on gait in relationship with the progress or involution of the child's functional development.

The Dark Side of Blocking RAS in Diabetic Patients with Incipient or Manifested Nephropathy.

Renin-angiotensin system (RAS) inhibitors are currently advocated as the first line approach for diabetic patients with high blood pressure, particularly if early signs of renal damage are manifest. This mostly relies on the supposed benefits of these drugs, either achieved indirectly by blood pressure lowering or directly by pleiotropic effects, on cardiovascular and renal outcomes. Yet, data from large randomized controlled trials and independent meta-analyses seem to raise some concerns on the compelling use of RAS-inhibitors in the whole diabetic population as improvements in cardiovascular and renal endpoints may not be as definite as generally believed. Furthermore, the risk of adverse events, such as hyperkalemia, deserves more attention in diabetic patients.In this brief review we aimed at summarizing the most relevant available evidence on "negative" or "null" effects of RAS-inhibitors on clinical outcomes in diabetic patients, providing reasons for a "personalized" rather than generalized use of these drugs according to individual characteristics.

Differentiation of myoendocrine cardiac cells from presumptive heart mesoderm explants of Bufo arenarum.

To investigate which factors are involved in the differentiation of Bufo arenarum heart myoendocrine cells, we studied the distribution of Atrial Natriuretic Peptide (ANP) immunoreactivity in hearts formed from presumptive cardiac mesoderm explanted at early embryo stages. Explants isolated from different embryonic stages throughout neurulation were cultured in vitro with or without the pharyngeal endoderm, and in other cases transplanted to the caudal region of embryos at similar stages. We utilized immunohistochemical and morphological techniques to assess myoendocrine cardiac cell differentiation. Development of heart beat and positive tropomyosin immunolabeling were considered signs of cardiac tissue differentiation. Our results confirm that explants of cardiac mesoderm cultured with endoderm showed a greater and more complete level of cardiac differentiation than those of mesoderm alone, and this coincides with the staining pattern of tropomyosin. ANP immunostaining revealed that cardiac cells containing ANP were scarce in those cultures without endoderm. On the contrary, in both cultured and grafted explants containing endoderm, ANP immunostaining was intensive and well-distributed in the cardiac tube, and in some cases restricted to one side of the formed heart. We conclude that the endoderm regulates cardiac cell differentiation, and in this way, is involved in the development of the heart myoendocrine system.

Differentiation of endocrine myocardiocytes in the developing heart of the toad (Bufo arenarum Hensel).

The differentiation of endocrine myocardiocytes was investigated in the heart of developing toad Bufo arenarum Hensel, combining ultrastructural and immunocytochemical procedures. The distribution of immuno-reactive atrial natriuretic peptide (ANP) in the whole heart was appraised by light microscopy, applying biotin-streptavidin and immunofluorescence techniques. With the latter procedures ANP was first recognized at embryonic stage 22, in both atrium and ventricle. In the ensuing stages the ANP-reactivity became stronger in the atrium, while it became dimmer in the ventricle. At the end of the larval prometamorphic stage, atrial myocardiocytes acquired almost all the features of adult myoendocrine cells. At electron microscope level, small inclusions, about 110-120 nm in diameter, resembling secretory granules were found in myoendocrine cells beginning at embryonic stage 22. However, no immunogold labeling of ANP occurred until stage 25. The number of secretory granules diminished in the ventricles and increased in the atrium of the larval heart and at the end of the prometamorphic stage the atrial myoendocrine cells presented the ultrastructural characteristics of active secretory cells. The synthesis of ANP in larvae is enhanced at a critical period of development when the developing toad switches from an aquatic environment to terrestrial life. The cardiac hormones seem to play a key role in the regulation of the osmolarity of body fluids at this developmental stage.

Expression of isoforms of the neural cell adhesion molecule (NCAM) and polysialic acid during the development of the Bufo arenarum olfactory system.

The neural cell adhesion molecule (NCAM), a member of the immunoglobulin superfamily that promotes Ca(2+)-independent cell-cell adhesion, is expressed as various isoforms generated by alternative splicing. In this study, the expression of the 180 kDa isoform (180-NCAM), total NCAM (180, 140 and 120 kDa isoforms) and the polysialic acid moiety of NCAM (PSA) were analyzed during the development of the olfactory system of the toad Bufo arenarum using specific antibodies and immunofluorescence light microscopy. NCAM and PSA were not found in the ectodermal thickening corresponding to the olfactory placode at early larval stage (stage 17), but by stage 19, total NCAM, 180-NCAM and PSA were all expressed in the invaginating olfactory placode at the sites of cell-cell contact and in the differentiating olfactory epithelium. Later, NCAM isoforms and PSA were found also in the primary fibers of the olfactory nerve and in the olfactory bulb. However, the expression of 180-NCAM decreased near the end of larval development and was absent in post-metamorphic and adult animals. In contrast, total NCAM (representing 140 and/or 120 kDa isoforms) and PSA continued to be expressed in olfactory tissues of post-metamorphic and adult animals, consistent with the persistent neural plasticity of this tissue. Because 180-NCAM has been associated with non-proliferating neurons, its down-regulation in post-metamorphic and adult olfactory system may be associated with the regenerative capability and continuous cell turnover documented for this region in adult animals.

Liver Regeneration Induced By Extracorporeal Portal Vein Arterialization in a Swine Model of Carbon Tetrachloride Intoxication.

INTRODUCTION: This study aimed to determine whether a controlled portal blood arterialization by a liver extracorporeal device (L.E.O2 NARDO) is effective in treating acute hepatic failure (AHF) induced in swine by carbon tetrachloride (CCl4) administration. MATERIALS AND METHODS: Sixteen swine with AHF induced by intraperitoneal injection of CCl4 in oil solution were randomly divided into 2 groups: animals that received L.E.O2 NARDO treatment 48 hours after the intoxication (study group; n = 8); and animals that were sham operated 48 hours after the intoxication (control group; n = 8). Blood was withdrawn from the iliac artery and reversed in the portal venous system by an interposed extracorporeal device. Each treatment lasted 6 hours. The survival was assessed at 5 days after L.E.O2 NARDO treatment or sham operation. In both groups blood samples were collected for biochemical analysis at different study time and liver biopsies were performed 48 hours after intoxication and at humane killing. RESULTS: In the study group decreased transaminases levels and a more rapid international normalized ratio (INR) recover were detected as compared with the control group. Six animals of the study group (75%) versus 1 animal (12.5%) of the control group survived at 5 days after surgery with a statistically significant difference (P < .05). Liver biopsies performed at humane killing showed damaged areas of the livers reduced in the study group compared with biopsies of the control group. CONCLUSIONS: Arterial blood supply in the portal system through the L.E.O2 NARDO device is easily applicable, efficacious, and safe in a swine model of AHF induced by CCl4 intoxication.

Capsular type distribution and susceptibility to antibiotics of Streptococcus pneumoniae clinical strains isolated from Uruguayan children with systemic infections. Pneumococcus Study Group.

Children under 24 months of age are at high risk for serious infection with Streptococcus pneumoniae but they do not elicit effective immune responses to the currently available capsular polysaccharide vaccines. A polysaccharide protein conjugated vaccine involving the most frequent types has become an urgent need. To produce such a vaccine for Latin America, information on type distribution is required. Recently, Uruguay was 1 of the 6 countries in Latin America where surveillance for invasive pneumococcal infections in children under the age of 5 years was carried out. Seventy percent of the 182 invasive S. pneumoniae isolates were recovered from patients under 24 months of age, and 19% were recovered from infants under 6 months. The 7 most frequent types were 14, 5, 1, 6B, 3, 7F, and 19A; representing 80% of invasive isolates. Twenty-one types were identified, 16 in pneumonia and 14 in meningitis. Resistance to penicillin increased during the study period, from 29% in 1994, to 40% in 1995-1996, mainly because of the spread of type 14 strains resistant to penicillin and trimethoprim/sulphamethoxazol (89% of resistant isolates). The high proportion of systemic pneumococcal infections recorded in patients under 24 months of age and the increasing resistance of these agents to first-choice antibiotics point to an urgent need for a capsular polysaccharide protein conjugated vaccine.

Microelectromechanical systems technology to deliver insulin.

A new microfabrication technology, microelectromechanical systems (MEMS), is envisioned for improved insulin delivery in the context of a device currently being developed for the Defense Advanced Research Projects Agency (DARPA). The drug delivery system utilizes MEMS technology to move and control fluids at the microscale, making possible the reconstitution and delivery of extremely small amounts of drug with extreme precision. In this article, the required microscale components that are currently being developed for the system are described. MEMS are made using fabrication methods similar to that utilized in microelectronics. Consequently, MEMS technology can be used to fabricate devices that are extremely small. The fundamental difference is that MEMS devices can either move themselves or control the movement of other materials, such as fluids. Furthermore, this manufacturing method is intrinsically low-cost and therefore is ideal for drug delivery systems. The current development of a new drug delivery system for controlled drug reconstitution and delivery system for DARPA is described as are the MEMS-based components for the required fluidic control. The adaptation of the system for insulin delivery is addressed and is envisioned to be a fully self-contained parenteral drug delivery system about the size of a 4-mm thick credit card.

A phase II study of VM-26 plus lonidamine in pretreated small cell lung cancer.

BACKGROUND: SCLC relapsing or refractory after induction chemotherapy is a chemoresistant tumor. The outcome of salvage chemotherapy is poor, with low response rates (< 30%) and short survival times (3-4 months). The development of drug resistance is considered the major cause of failure of treatment. VM-26 is one of the most active drugs in SCLC. Lonidamine has shown to enhance in both vivo and vitro antitumor activity of several cytotoxic drugs acting on drug resistance mechanisms. MATERIALS AND METHODS: VM-26 and lonidamine were employed as salvage chemotherapy in 30 small cell lung cancer patients. The doses of chemotherapy used were: VM-26 100 mg/m2, i.v., days 1 to 3; lonidamine 600 mg, p.o., days 1 to 5, recycled every 3 weeks. RESULTS: We observed 13.3% of objective response and a median survival of 4 months. All the responses were obtained in patients relapsing after a response to induction chemotherapy. Toxicity was moderate with no toxic death. CONCLUSIONS: Our study shows that Lonidamine failed to increase the VM-26 activity in pretreated small cell lung cancer patients.

Ultrastructural study on thyroid glands of Bufo arenarum larvae kept in potassium perchlorate solution.

The ultrastructure of thyroid glands in Bufo arenarum tadpoles was studied with inhibited thyroid function. After hatching, larvae were kept in potassium perchlorate solution, a goitrogenic substance known to prevent absorption of iodine from water or food, resulting in impaired thyroid hormone synthesis. Increased thyroid gland volume and follicular cell height were observed in treated larvae. The changes in size and volume of follicular cells in experimental tadpoles appeared to be mainly a function of the overstimulation of proteinpoietic apparatus. The cell shows a conspicuous development of endoplasmic reticulum and Golgi complex, as well as an increase in number of mitochondria and colloid droplets. These observations in follicular thyroid cells from Bufo arenarum, obtained under such experimental conditions, were interpreted in terms of interruption of negative feedback mechanisms involving the decrease in the thyroxine circulatory level, and therefore the increase in hypothalamo-hypophyseal endocrine secretory stimulation.

Presence and release of immunoreactive atrial natriuretic peptide (ANP) in Bufo arenarum spermatozoa after HCG treatment.

Atrial natriuretic peptide (ANP)-like immunoreactivity has been demonstrated in mature spermatozoa of Bufo arenarum. However, after spermiation induced by Gonadotropin Releasing Hormone (GnRH), no ANP immunoreactivity was detected in testicular spermatozoa. Recently, the presence of GnRH and GnRH receptors in amphibian testes has been demonstrated. To clarify if the loss of ANP-like immunoreactivity in spermatozoa is a direct effect of GnRH or pituitary gonadotropins, a study on Bufo arenarum adult males, has been performed. The in vivo treatment with Human Chorionic Gonadotropin (HCG) induced spermiation and loss of ANP-like immunoreactivity. The in vitro treatment with HCG showed the same results. However, in vitro GnRH treatment failed to cause spermiation and loss of ANP-like immunoreactivity. The present results indicate that ANP from mature spermatozoa is regulated via gonadotropic hormones and may be involved in the spermiation process.