Outbreak Investigation of Typhoid Fever in the District of Gabes, South of Tunisia

Typhoid fever is a significant public health concern in many parts of the world, particularly in developing countries with poor sanitation and hygiene conditions. In July 2016, an outbreak of typhoid fever occurred in Ghannouche, located in the south of Tunisia. This paper reports the results of a field investigation undertaken to identify possible transmission pathways and risk factors in order to propose control and preventive measures. A retrospective cohort study including a passive and active case finding, as well as an environmental and bacteriological investigation was conducted from July to September 2016. A case was defined as a person residing or having stayed in Ghannouche and having presented from the beginning of June clinical signs suggestive of typhoid fever, with, for a confirmed case, laboratory isolation of S.Tyhi, and for a probable case, an epidemiological link with a confirmed case. Attack rates were determined, and risk ratios were estimated with respect to exposures. Unadjusted and adjusted odds ratios were estimated using binary logistic regression. Among the 628 subjects investigated, 102 cases of typhoid fever were identified (74 confirmed and 28 probable) with an overall attack rate of 16.24%. Over 56% of cases were male and those under 10 years old were most affected (38.2%% of cases) with a median age of 12 years (interquartile range 5 to 25 years). The main clinical signs were fever (95%) and diarrhea (57%). Young age (adjusted OR = 0.95 and 95% CI = 0.93-0.97), low level of education (adjusted OR = 4.76 and 95% CI = 1.34-16.81), and the habitat type Arab or rudimentary house (adjusted OR = 4.93 and 95% CI = 2.61-8.27) were the socio-demographic factors independently associated with typhoid fever. Typhoid fever was found to be associated with drinking softened water (adjusted OR = 2.64 and 95% CI = 1.16-4.82), eating raw fruit and vegetables from family gardens (adjusted OR = 6.13 and 95% CI = 3.66-11.06), and using uncontrolled waste disposal (adjusted OR = 3.52 and 95% CI = 2.03-6.94). A total of 110 drinking water samples were analyzed; out of the 38 samples of softened water, 12 were non-compliant and 5 were positive for Salmonella. The screening activity identified two asymptomatic carriers, one of whom was a softened water seller. We concluded that drinking softened water from informal or unauthorized sale units, consuming fruit and vegetables from family gardens, uncontrolled dumping of household waste, and poor socio-economic conditions increase the risk of typhoid fever in this region. Many recommendations were implemented to stop this outbreak and to prevent further episodes.

Structural and functional integrity of Sulla carnosa photosynthetic apparatus under iron deficiency conditions

The abundance of calcareous soils makes bicarbonate-induced iron (Fe) deficiency a major problem for plant growth and crop yield. Therefore, Fe-efficient plants may constitute a solution for use on calcareous soils. We investigated the ability of the forage legume Sulla carnosa (Desf.) to maintain integrity of its photosynthetic apparatus under Fe deficiency conditions. Three treatments were applied: control, direct Fe deficiency and bicarbonate-induced Fe deficiency. At harvest, all organs of deficient plants showed severe growth inhibition, the effect being less pronounced under indirect Fe deficiency. Pigment analysis of fully expanded leaves revealed a reduction in concentrations of chlorophyll a, chlorophyll b and carotenoids under Fe deficiency. Electron transport rate, maximum and effective quantum yield of photosystem II (PSII), photochemical quenching (qP), non-photochemical quenching (qN) as well as P700 activity also decreased significantly in plants exposed to direct Fe deficiency, while qN was not affected. The effects of indirect Fe deficiency on the same parameters were less pronounced in bicarbonate-treated plants. The relative abundances of thylakoid proteins related to PSI (PsaA, Lhca1, Lhca2) and PSII (PsbA, Lhcb1) were also more affected under direct than indirect Fe deficiency. We conclude that S. carnosa can maintain the integrity of its photosynthetic apparatus under bicarbonate-induced Fe deficiency, preventing harmful effects to both photosystems under direct Fe deficiency. This suggests a high capacity of this species not only to take up Fe in the presence of bicarbonate (HCO₃^- ) but also to preferentially translocate absorbed Fe towards leaves and prevent its inactivation.

Sulla carnosa modulates root invertase activity in response to the inhibition of long-distance sucrose transport under magnesium deficiency

Being the principal product of photosynthesis, sucrose is involved in many metabolic processes in plants. As magnesium (Mg) is phloem mobile, an inverse relationship between Mg shortage and sugar accumulation in leaves is often observed. Mg deficiency effects on carbohydrate contents and invertase activities were determined in Sulla carnosa Desf. Plants were grown hydroponically at different Mg concentrations (0.00, 0.01, 0.05 and 1.50 mM Mg) for one month. Mineral analysis showed that Mg contents were drastically diminished in shoots and roots mainly at 0.01 and 0.00 mM Mg. This decline was adversely associated with a significant increase of sucrose, fructose and mainly glucose in shoots of plants exposed to severe deficiency. By contrast, sugar contents were severely reduced in roots of these plants indicating an alteration of carbohydrate partitioning between shoots and roots of Mg-deficient plants. Cell wall invertase activity was highly enhanced in roots of Mg-deficient plants, while the vacuolar invertase activity was reduced at 0.00 mM Mg. This decrease of vacuolar invertase activity may indicate the sensibility of roots to Mg starvation resulting from sucrose transport inhibition. ¹⁴ CO₂ labeling experiments were in accordance with these findings showing an inhibition of sucrose transport from source leaves to sink tissues (roots) under Mg depletion. The obtained results confirm previous findings about Mg involvement in photosynthate loading into phloem and add new insights into mechanisms evolved by S. carnosa to cope with Mg shortage in particular the increase of the activity of cell wall invertase.

Sulla carnosa modulates root invertase activity in response to the inhibition of long-distance sucrose transport under magnesium deficiency

Being the principal product of photosynthesis, sucrose is involved in many metabolic processes in plants. As magnesium (Mg) is phloem mobile, an inverse relationship between Mg shortage and sugar accumulation in leaves is often observed. Mg deficiency effects on carbohydrate contents and invertase activities were determined in Sulla carnosa Desf. Plants were grown hydroponically at different Mg concentrations (0.00, 0.01, 0.05 and 1.50 mM Mg) for one month. Mineral analysis showed that Mg contents were drastically diminished in shoots and roots mainly at 0.01 and 0.00 mM Mg. This decline was adversely associated with a significant increase of sucrose, fructose and mainly glucose in shoots of plants exposed to severe deficiency. By contrast, sugar contents were severely reduced in roots of these plants indicating an alteration of carbohydrate partitioning between shoots and roots of Mg-deficient plants. Cell wall invertase activity was highly enhanced in roots of Mg-deficient plants, while the vacuolar invertase activity was reduced at 0.00 mM Mg. This decrease of vacuolar invertase activity may indicate the sensibility of roots to Mg starvation resulting from sucrose transport inhibition. ¹⁴ CO₂ labeling experiments were in accordance with these findings showing an inhibition of sucrose transport from source leaves to sink tissues (roots) under Mg depletion. The obtained results confirm previous findings about Mg involvement in photosynthate loading into phloem and add new insights into mechanisms evolved by S. carnosa to cope with Mg shortage in particular the increase of the activity of cell wall invertase.

Exogenous proline mediates alleviation of cadmium stress by promoting photosynthetic activity, water status and antioxidative enzymes activities of young date palm (Phoenix dactylifera L.)

The ability of exogenous compatible solutes, such as proline, to counteract cadmium (Cd) inhibitory effects in young date palm plants (Phoenix dactylifera L. cv Deglet Nour) was investigated. Two-year-old date palm plants were subjected for five months at different Cd stress levels (0, 10 and 30 mg CdCl2 kg(-1) soil) whether supplied or not with exogenous proline (20mM) added through the irrigation water. Different levels of Cd stress altered plant growth, gas exchanges and chlorophyll content as well as water status, but at different extent among them. In contrast, an increase of antioxidant enzymes activities of Cd-treated plants in association with high amounts of proline content, hydrogen peroxide (H2O2), thiobarbituric acid reactive substances (TBARS) and electrolyte leakage (EL) were observed. Interestingly, exogenous proline mitigated the adverse effects of Cd on young date palm. Indeed, it alleviated the oxidative damage induced by Cd accumulation and established better levels of plant growth, water status and photosynthetic activity. Moreover, proline-treated plants showed high antioxidant enzymes activities (superoxide dismutase, catalase and glutathione peroxydase) in roots and leaves as compared to Cd-treated plants.

[Pulmonary nocardiosis and sarcoidosis]

Infectious complications are rarely observed in the course of sarcoidosis. Only small series or cases reports of infection are described in sarcoidosis. Corticosteroids-induced immune suppression, pulmonary fibrosis and T-CD4 lymphopenia, are often present. Pulmonary nocardiosis is an important cause of opportunistic infection in immunosuppressed patients, and the incidence of this infection is increasing. Pulmonary nocardiosis manifests as an acute, subacute or chronic infection with a marked tendency towards remissions and exacerbations. We report a case of pulmonary nocardiosis in a patient with sarcoidosis followed for pulmonary fibrosis receiving corticosteroids. During the investigation of pyrexia and dyspnea, evidence of Nocardia spp. infection was found in the bronchial secretions. Six months of trimethoprim/sulfamethoxazole therapy ensured further resolution of this pleuropulmonary infection. Pulmonary nocardiosis is exceptional in sarcoidosis and mainly occur, in patients receiving corticosteroids, and with CD4+ T-lymphocytopenia. Sarcoidosis by itself does not appear to be a risk factor of opportunistic infection.

Physiological and anatomical adaptations induced by flooding in Cotula coronopifolia

Cotula coronopifolia is a wild annual Asteraceae that grows in periodically-flooded prone environments and seems highly tolerant to periodic flooding. Seedlings of about 15 cm were collected directly from the edge of Soliman sabkha (N-E Tunisia, semi-arid stage) and grown under greenhouse conditions. Two treatments were considered: drainage and flooding. After 56 days of treatment, flooded plants showed a pronounced growth increase. This performance was essentially associated with significant increment in biomass production of both shoots and roots (about 220% of the control). The appropriate response to flooding was also characterized by the ability of the species to maintain its water status under such conditions. Neither water content nor water potential showed a significant variation as compared to those of non-flooded plants. However, transpiration rate decreased slightly but significantly in flooded plants (from 0.86 to 0.64 mmol H2O m-2 s-1). Na+ and K+ concentrations were practically maintained under waterlogging conditions, except a significant increase of Na+ content in roots of flooded plants (157% of the control). These responses were concomitant with maintenance of photosynthetic rate. However, the contents of chlorophylls a and b increased to 167% and 295%, respectively. It seems that the enhancement in these photosynthetic pigments together with a significant improvement in water use efficiency (from 4.66 to 6.07 mmol CO2 mol-1 H2O) allowed to the species to compensate the decrease in photosynthetic rate. At the anatomical level, this species responded to flooding by a significant development of its root aerenchyma (+63%) and an increase in the lignification of its stem xylem tissues (+37%). Based on the presented data, the plant fitness under flooding conditions was a result of dynamic readjustment of several morphological, physiological, and anatomical adaptive traits. Flood requirement together with salt tolerance are responsible for the predominance of C. coronopifolia in a large area in its natural biotope where most plants cannot tolerate interactive effects of flooding and salinity.

Nutrient uptake and management under saline conditions in the xerohalophyte: Tecticornia indica (Willd.) subsp. indica

In the present investigation, we studied uptake and management of the major cations in the xerohalophyte, Tecticornia indica (Willd.) subsp. indica as subjected to salinity. Plants were grown under greenhouse conditions at various salinity levels (0, 100, 200 and 400 mM NaCl) over 110 days. At harvest, they were separated into shoots and roots then analyzed for water contents, dry weights (DW), and Na+, K+, Ca²+, and Mg²+ contents. Plants showed a growth optimum at 200 mM NaCl and much better tissue hydration under saline than non-saline conditions. At this salt concentration (200 mM NaCl), shoot Na+ content reached its highest value (7.9 mmol · g-⁻¹ DW). In spite of such stressful conditions, salt-treated plants maintained adequate K+, Ca²+, and Mg²+ status even under severe saline conditions. This was mainly due to their aptitude to selectively acquire these essential cations and efficiently use them for biomass production.

Rm62, a DEAD-box RNA helicase, complexes with DSP1 in Drosophila embryos

Two main classes of proteins, Polycomb group (PcG) and Trithorax group (TrxG), play a key role in the regulation of homeotic genes. These proteins act in multimeric complexes to remodel chromatin. A third class of proteins named Enhancers of Trithorax and Polycomb (ETP) modulates the activity of TrxG and PcG, but their role remains largely unknown. We previously identified an HMGB-like protein, DSP1 (Dorsal Switch Protein 1), which was classified as an ETP. Preliminary studies have revealed that DSP1 is involved in multimeric complexes. Here we identify a DEAD-box RNA helicase, Rm62, as partner of DSP1 in a 250-kDa complex. Coimmunoprecipitation assays performed on embryo extracts indicate that DSP1 and Rm62 are associated in 3- to 12-h embryos. Furthermore, DSP1 and Rm62 colocalize on polytene chromosomes. Consistent with these results, a mutation in Rm62 enhances a null mutation of dsp1 and also mutations of trxG or PcG, suggesting that Rm62 has characteristics of an ETP. We show here for the first time that an RNA helicase is involved in the maintenance of homeotic genes.

Physiological responses of Arabidopsis thaliana to the interaction of iron deficiency and nitrogen form

Physiological responses of Arabidopsis thaliana to the interaction of iron deficiency and nitrogen form were studied using plants grown in hydroponics. Thirty-three-day-old seedlings were submitted to four treatments for 7 days: NO 3 + 5 microM Fe; NO 3 + 0.1 microM Fe; NH 4 + 5 microM Fe and NH 4 + 0.1 microM Fe. Leaf growth and chlorophyll content were highest in NO 3 -fed, Fe sufficient plants, but were strongly diminished by Fe deficiency under nitric nutrition, and by ammoniacal nutrition independently of Fe regime. However, the leaves of NH 4 -fed plants presented a higher Fe content than those of Fe sufficient, NO 3 -fed plants. Thus, leaf chlorosis of NH 4 -fed in plant did not depend on Fe availability, and seemed to be due to another factor. Root acidification capacity and Fe-chelate reductase (FCR) activity were also dependent on N form. The medium was acidified under ammoniacal regime and alkalinized under nitric regime regardless of Fe level. FCR activity stimulation in response to Fe deficiency was observed only in NO 3- fed plants. In addition, both N form and Fe level induced antioxidant responses in rosette leaves. Ammoniacal regime increased both peroxidase expression and anthocyanin accumulation, whereas Fe deficiency enhanced superoxide dismutase expression.

Interactive effects of salinity, nitrate, light, and seed weight on the germination of the halophyte Crithmum maritimum

Interaction of salinity, nitrate, light, and seed weight on the germination of Crithmum maritimum was investigated. Seeds of three size categories were germinated at 0-200 mM NaCl with either 0, 5 or 20 mM KNO 3 . Experiments were done under darkness, white light, or red light. Regardless of seed weight, germination was maximal in distilled water. Under salinity, the smallest seeds showed the highest germination percentage. Salt impact was amplified by darkness, but was mitigated by nitrate supply, red light and their combination. At the same PPFD, germination of T2 seeds was higher, when exposed to red light than under white light, suggesting that germination was more influenced by the light type than by the PPFD. As a whole, not only salinity, nutrient availability, seed weight, and light, but also their interaction may control the germination of this halophyte.

[Nodular liver lesions with fever in a Moroccan man: hepatic brucelloma]

Hepatic brucelloma is an exceptional localization in brucellosis. The purpose of this report is to describe an uncommon case involving a 42-year-old man hospitalized for febrile hepatic cytolysis. Diagnosis was established based on positive rose bengal test results, positive blood culture, hypoechogenic masses on ultrasound, and hypodense enhancing masses on CT scan. Hepatic brucelloma is a focal suppurative lesion occurring after undetected acute brucellosis or undertreated brucellosis. Diagnosis is based on the association of imaging showing characteristic features (hepatic calcifications) and on positive blood culture and serology. First-line treatment should consist of doxycyclin and rifampicin for 2 to 12 months. If medical treatment fails, surgical drainage should be performed.

[Celiac crisis with quadriplegia due to potassium depletion as presenting feature of celiac disease]

INTRODUCTION

Adult coeliac disease revealed by coeliac crisis and quadriplegia due to potassium depletion is an extremely rare situation.

CASE REPORT

A 26-year-old woman presented with a suddenly developed weakness of all four limbs and a severe diarrhea. Authors emphasize coeliac crisis, which is a presenting feature of coeliac disease, characterized by acute diarrhea with life-threatening acid base and electrolyte abnormalities. The patient improved with correction of hypokalemia and gluten-free diet.

CONCLUSION

A severe acute diarrhea with metabolic and systemic complications, the so-called coeliac crisis, is a possible presenting clinical feature of a previously undiagnosed adult celiac disease.

[Primary gastric lymphoma: a retrospective series of 35 cases]

BACKGROUND

Primary gastric non Hodgkin's lymphoma (PGNHL) is the most common site of extranodal malignant lymphoma. It is a rare subtype of malignancy, for which no consensus exists about treatment.

AIM

The purpose of This paper was to assess the managemnt of PGNHL.

METHODS

Between January 1992 and December 2001, 35 patients were retrospectively evaluated.

RESULTS

Of the 35 patients, with a mean age of 44 years old Signs and symptoms are unspecific. 20 (57.1%) were in stage IE/IIE1. 15 patients (42.8%) were in stage IIE2,IIIE,IVE. These patients were treated with primary surgery with or without chemotherapy (11; 31.4%); primary chemotherapy (CT) alone with surgery in one patient (21; 60%) and three patients with gastric MALT lymphoma were treated by Helicobacter pylori eradication. The 5 year survival rates of the 35 patients are 62, 86%. There was no significant difference in the 5 year survival rate between the patients with low grade lymphoma and the patients with large grade lymphoma (75% versus 60%, P = 0.467). The 5-year survival rates for stage I/IIE1 and IIE2/III/IV patients were 80%, 53.3% respectively (p < 0.144). Of the 11 primary surgical groups with or without chemotherapy, the 5 year survival rate is 90.9%. Of the 21 patients who received CT, alone or combined with surgery, the survival rate is 52.4%. There was significant difference between the two groups (P = 0.05). Of the 3 patients with low-grade mucosa-associated lymphoid tissue (MALT) lymphoma with only oral anti-Helicobacter pylori regimen remained disease-free after a median follow-up of two years.

CONCLUSIONS

This study suggested that primary surgical resection may be important factor predicting the long-term survival of patients with primary gastric NHL. H. pylori eradication therapy was an effective first-line treatment for patients with gastric MALT lymphoma.

[Hodgkin's disease presenting with spinal cord compression]

INTRODUCTION

Hematological neoplasms may be complicated by signs of neurological compression. Most cases reported in the literature have described advanced-stage non-Hodgkin lymphomas. We report a case of spinal cord compression revealing an isolated vertebral localization of Hodgkin lymphoma.

CASE REPORT

Magnetic resonance imaging of the thoracic spine in a 54-year-old man who presented with spastic paraplegia revealed a vertebral and extradural mass. After laminectomy, histology and immunohistochemistry showed Hodgkin's disease. Post-operative staging did not reveal any other localization. The patient responded favorably after decompressive surgery and ABVD regimen.

CONCLUSION

Spinal cord compression is a rare complication of Hodgkin's disease, occurring in only 5p.cent of cases, usually in the setting of progressive, advanced disease. As the initial symptom of Hodgkin's disease, it is extremely rare, with only a few cases reported in the literature. Significant results may be obtained with decompressive surgery and chemotherapy when the disease is promptly diagnosed. Spinal cord compression by primary Hodgkin's disease is a very infrequent situation. We urge this diagnosis be considered in all patients presenting with spinal cord compression attributed to malignancy.

[Silent myocardial infarction and antiphospholipid antibody syndrome]

We describe a case of 18-year-old woman followed for 3 years for systemic lupus erythematosis (SLE) complicated of a nephrectomy. Having like only factor of cardiovascular risk a balanced arterial hypertension. The patient was hospitalized because of choreo-athetosic's movement. We discovered fortuitously during this hospitalization an inferior myocardial necrosis as well as a mitral regurgitation. Coronary angiography was normal and the ventriculography showed an akinesy in the inferior territory. Biology made it possible to pose the diagnosis of antiphospholipid antibody syndrome (APS) on (SLE). We suppose that surgery started myocardial necrosis and underline through this case interest of early identification and appropriate treatment of APS as well as a narrow monitoring particularly in young patients candidates to surgery.

Hyperplasie angiolymphoïde à éosinophiles

INTRODUCTION

Angiolymphoid hyperplasia with eosinophilia is a rare affection.

CASE REPORT

A 36 years-old woman presented an angiolymphoid hyperplasia with eosinophilia manifesting by erythematous nodular lesions on the face and the forearms, severe neuropathy, visual loss and eosinophilia. Corticosteroids, immunosuppressive drugs and interferon-alpha were unsuccessful.

DISCUSSION

Angiolymphoid hyperplasia with eosinophilia is a dermatological disease with possible systemic features. Differential diagnosis with Kimura disease is based on clinical presentation and histological findings. Etiopathology remains unknown and the treatment is not codified.

[Faunistic note on Culcoides (Diptera, Ceratopogonidae) from the governate of Monastir (Tunisia)]

Following the arrival of blue-tongue in Tunisia, the authors report the results of the first survey made in Monastir. They show the existence of nine species of Culicoides, three of which are new to the country IC. paolae, C. imicola, C. newsteadi), that now brings to 22 the number of the known species.

[Isolated pseudo-tumoral tuberculosis of the spleen. A case report]

INTRODUCTION

The tuberculosis isolated tumoral spleen is rare, even in the countries to strong tubercular endemic.

EXEGESIS

From an observation, concerning an important, tumoral and isolated splenomegaly in 48-year-old-man. The authors put the accent on his tumorous variety by the clinic, the imagery and on macroscopic appearance of the operative piece. Are discussed the isolated character, the way of dissemination, the site of initial infestation and the deceitful character of haematological manifestations. A splenectomy to diagnostic and therapeutic goal have been realised, associated to the chemotherapy.

CONCLUSION

This is an expression of the profound organ's tuberculosis rich on endothelial reticular system. It's mean a singular topography of the bacillary lesion and a great distribution of the tubercular affect.

[Non-Hodgkin's lymphoma and hepatitis C virus infection]

INTRODUCTION

The authors report four cases of non Hodgkin's lymphomas (NHL) among patients infected by the hepatitis C virus (HCV). They discuss the epidemiological, physiopathological and clinical features of this association.

CURRENT KNOWLEDGE AND KEY POINTS

The role of the HCV in the development of B-cell NHL is probable but the reported frequency of the association with HCV infection is variable especially in different countries. Most of the reported cases are low-grade NHL with frequent extranodal involvement.

FUTURE PROSPECTS AND PROJECTS

New studies will improve the understanding of the physiopathological mechanisms that might explain the occurrence of NHL in the course of HCV infection. The recent evidence that the antiviral treatment is effective in splenic lymphoma with villous lymphocytes leads to reconsider the relationship between HCV and NHL and to think about new therapeutic possibilities.

Historadioautographic localization of oxytocin and V1a vasopressin binding sites in the kidney of developing and adult rabbit, mouse and merione and of adult human

The localization of oxytocin (OT) binding sites and vasopressin (VP) binding sites of the V1a subtype was investigated by radioautography in kidneys of rabbits, mice and meriones during postnatal development and in the adult, and in the human kidney. Kidney sections were incubated in the presence of selective radioiodinated OT and V1a antagonists, respectively. The localizations were compared with those previously described in the rat. The main finding of the study was the almost constant presence in the cortex of V1a binding sites in the connecting tubule, the cortical collecting duct and in the juxtaglomerular apparatus (on the intra- and extraglomerular mesangium and the afferent arteriole). This distribution suggests an interaction of VP via V1a receptors and the kallikrein-kinin system in the kidney. OT binding sites, in comparison with V1a binding sites, were fewer and less constantly detectable in the kidney of the different species. In the mouse, their presence on the limbs of Henle's loop in the medulla points to the possibility of their involvement in the medullary concentrating process. In the kidneys of the various species, OT and V1a binding sites occurred always in differential structures. In contrast, in the human kidney cortex, a colocalization of OT and V1a binding sites was almost constantly observed. This raises the question as to the specificity of the neurohypophysial hormone receptors in the human kidney.

[Relapsing polyneuropathy in the post-partum period]

A patient had five relapses of polyneuropathy: four developed during post-partum. The rapid onset of symptoms with subsequent complete recovery are in favor of a recurrent Guillain-Barré syndrome rather than a chronic relapsing inflammatory polyneuropathy.

Historadioautographic localisation of oxytocin and vasopressin binding sites in the central nervous system of the merione (Meriones shawi)

The distribution of vasopressin and oxytocin binding sites in the central nervous system of the merione (Meriones shawi), a rodent adapted to desert life, was studied by means of conventional film radioautography at macroscopic scale and historadioautography at cellular level using radioiodinated ligands highly selective for either oxytocin or type V1 a vasopressin receptors. Both types of binding sites exhibited the same selectivity for endogenous peptides as in the rat. Distribution of oxytocin binding sites was similar in some structures (limbic system, spinal cord) to that described in the rat and in other rodents. Vasopressin binding sites were much more widely distributed in the merione than in the rat brain. In addition to locations common to most rodents (lateral septum and suprachiasmatic nucleus), in merione vasopressin binding sites occurred in several areas known to express oxytocin binding sites in the rat (olfactory system, hypothalamus). Colocalisation of vasopressin and oxytocin binding sites, which occurred in the CA1 and CA2 fields of Ammon's horns of the hippocampus, the caudate-putamen and the fundus striati of the merione, has so far not been reported in any other rodent.

Development of the hypothalamic vasopressin system and nephrons in Meriones shawi during ontogenesis

This study has evaluated the development of the hypothalamic vasopressin system and nephrons of the kidney in desert rodents, Meriones shawi, which effectively retain water by excretion of highly concentrated urine. The vasopressin system was studied immunocytochemically at the 18th fetal day, at the 2nd, 13th, 27th postnatal days and in adulthood. The kidneys were investigated at the 2nd, 13th postnatal days and in adulthood using microdissection technique. Occasional vasopressin-immunoreactive neurons were observed as early as the 18th fetal day, only in the paraventricular nucleus. From the 2nd postnatal day onwards, vasopressin neurons increased progressively in number, being mainly concentrated in the supraoptic and paraventricular nuclei, as well as in the ventral retrochiasmatic region. Transient neuronal populations were also observed at the 13th postnatal day in the lateral preoptic area and anterior hypothalamic nucleus. Apart from the neurons, the glandular cells of the tuberal lobe showed immunostaining from the 18th fetal day, the first age studied, until the 13th postnatal day. The fibers of differentiating vasopressin neurons grew towards the circumventricular/neurohemal organs, terminating in the organum vasculosum of the lamina terminalis and the lateral ventricles as early as the 18th fetal day, as well as the third ventricle, the posterior lobe and the external zone of the median eminence between the 2nd and 13th postnatal days. The kidney in 2-day-old Meriones comprised nephrons at different stages of development from an S-shaped body to well-differentiated nephrons. At the 13th postnatal day, as in adulthood, the nephrons were well differentiated and characterized by long, thin loops descending to different levels of papilla. Thus, according to our morphological data the hypothalamic vasopressin neurons and nephrons in the kidney of Meriones reach the definitive state by the end of the 2nd postnatal week.

Central GABAergic innervation of the pituitary in goldfish: a radioautographic and immunocytochemical study at the electron microscope level

The GABAergic innervation of the goldfish pituitary was studied at the light and electron microscope levels by means of radioautography after in vitro incubation in tritiated gamma-aminobutyric acid (GABA) and immunocytochemistry using antibodies against GABA. Following incubation of pituitary fragments in a medium containing tritiated GABA, a selective uptake of the tracer was observed within the digitations of the neurohypophysis. Silver grain clusters were also observed in the adenohypophyseal tissue. At the electron microscope level, this uptake was found to correspond to nerve endings containing small clear and dense-core vesicles. These labeled profiles were located mainly in neurohypophyseal digitations in close apposition with the basement membrane separating the neurohypophysis from the adenohypophysis. However, they were also encountered in direct contact with most adenohypophyseal cell types in the different lobes. These results were confirmed by immunocytochemical data demonstrating the presence of numerous GABA immunoreactive fibers in both anterior and neurointermediate lobes. They were found either in the digitations of the neurohypophysis or in the adenohypophysis in direct contact with the glandular cells with a distribution and an ultrastructural aspect similar to those observed by radioautography. These data demonstrate that the pituitary of teleosts receives a massive GABAergic innervation. Although physiological data providing a functional significance for such an innervation are lacking, the present study suggests that, as already documented in mammals, GABA may be involved in the neuroendocrine regulation of pituitary functions in teleosts.

Immunocytochemical study of the GABAergic innervation of the mouse pituitary by use of antibodies against gamma-aminobutyric acid (GABA)

The GABAergic innervation of the mouse pituitary, including the median eminence, was studied at light-microscopic and ultrastructural levels by use of a pre-embedding immunocytochemical technique with antibodies directed against GABA. In the median eminence, a high density of GABA-immunoreactive fibers was found in the external layer where the GABAergic varicosities were frequently observed surrounding the blood vessels of the primary capillary plexus. In the internal and subependymal layers, only few fibers were immunoreactive. The intense labeling of the external layer was observed in the entire rostro-caudal extent of the median eminence. In the pituitary proper, a dense network of GABA-immunoreactive fibers was revealed throughout the neural and intermediate lobes, entering via the hypophyseal stalk. The anterior and tuberal lobes were devoid of any immunoreactivity. The GABA-immunoreactive terminals were characterized in the median eminence, and in the intermediate and posterior lobes at the electron-microscopic level. They contained small clear vesicles, occasionally associated with dense-core vesicles or neurosecretory granules. In the intermediate lobe they were seen to be in contact with the glandular cells. In the posterior lobe and in the median eminence, GABA-immunoreactive terminals were frequently located in the vicinity of blood vessels. These results further support the concept of a role of GABA in the regulation of hypophyseal functions, via the portal blood for the anterior lobe, directly on the cells in the intermediate lobe, and via axo-axonic mechanisms in the median eminence and posterior lobe.