Organic phosphorus affects the retention of arsenite and arsenate by goethite

The hazardous effects of arsenic are closely linked to its speciation and interaction with different soil minerals, which influence both As mobility and bioavailability. Adsorption onto iron (oxyhydr)oxides is one of the main processes controlling the partitioning of arsenite [As(III)] and arsenate [As(V)] between aqueous and solid phases. Arsenic retention can be affected by changes in soil pH and the presence of competing anions, like phosphate. Although competition with inorganic phosphorus (P) for sorption sites on mineral surfaces has been widely studied, little is known about the interactions with organic P (P_o ) compounds, in particular inositol phosphates, even though they may represent a large fraction of total soil P. We quantified the effects of myo-inositol hexaphosphate (InsP6) on the adsorption and retention of As(III) and As(V) on goethite as influenced by pH, the order of anion addition, and residence time. The efficiency of InsP6 in displacing adsorbed As(III) decreased with increasing pH values and interaction time, which may be attributed to the increase in bonding strength of the As(III) complexes on the surface of goethite. Adsorption and retention of As(V) by goethite generally decreased with increasing pH, particularly in the presence of InsP6 due to the similar pK_a values and the competition for the same binding sites. The addition of InsP6 before, together with, or after adsorption of As(III) and As(V) strongly reduced the amounts of sorbed As, suggesting that the addition of P_o -rich matrices to As-contaminated soils may strongly enhance As mobility.

Allergen-loaded strontium-doped hydroxyapatite spheres improve allergen-specific immunotherapy in mice

BACKGROUND

Immunomodulatory interventions play a key role in the treatment of infections and cancer as well as allergic diseases. Adjuvants such as micro- and nanoparticles are often added to immunomodulatory therapies to enhance the triggered immune response. Here, we report the immunological assessment of novel and economically manufactured microparticle adjuvants, namely strontium-doped hydroxyapatite porous spheres (SHAS), which we suggest for the use as adjuvant and carrier in allergen-specific immunotherapy (ASIT).

METHODS AND RESULTS

Scanning electron microscopy revealed that the synthesis procedure developed for the production of SHAS results in a highly homogeneous population of spheres. Strontium-doped hydroxyapatite porous spheres bound and released proteins such as ovalbumin (OVA) or the major cat allergen Fel d 1. SHAS-OVA were taken up by human monocyte-derived dendritic cells (mdDCs) and murine DCs and did not have any necrotic or apoptotic effects even at high densities. In a murine model of ASIT for allergic asthmatic inflammation, we found that OVA released from subcutaneously injected SHAS-OVA led to a sustained stimulation of both CD4⁺ and CD8⁺ T cells. Allergen-specific immunotherapy with SHAS-OVA as compared to soluble OVA resulted in similar humoral responses but in a higher efficacy as assessed by symptom scoring.

CONCLUSION

We conclude that SHAS may constitute a suitable carrier and adjuvant for ASIT with great potential due to its unique protein-binding properties.

In vitro embryotoxicity study of n,n-dimethylacetamide and its main metabolite N-monomethylacetamide

N,N-Dimethylacetamide (DMAC) is a widely used industrial solvent. Previous teratological studies in vivo reported discording results. Using the postimplantation rat whole embryo culture (WEC) method, the direct embryotoxic effects of DMAC and its main metabolite (N-monomethylacetamide, MMAC) have been investigated in the present work. Both chemicals showed specific embryotoxic and teratogenic effects at similar concentration levels. The no-observed-effect level (NOEL) was 0.85mm.Macroscopically, the main target organs were somites, brain and branchial bars. Histological examination revealed an increase in cell death at the effective concentrations on the neuroepithelium and branchial bars mesenchyme. The results of this work, together with those obtained in in vivo studies, suggest that the exposure limits in workplaces could be inappropriate for the safety of fertile women.

Surgical treatment of inflammatory bowel diseases in northwestern Italy: a multicentric study by the G.S.M.I.I. (Inflammatory Bowel Disease Study Group)

BACKGROUND AND AIMS

Improved medical therapy and bowel sparing and sphincter saving techniques have changed surgery for UC and CD. Collaboration between gastroenterologists and surgeons is necessary to uniform the indications for surgical treatment reducing emergency operations. GISMII multicentric study aimed to show indications, timing and impact of surgery, through retrospective analysis of cases observed between 1992 to 1996.

METHODS

Data were obtained by 16 departments of General Surgery.

RESULTS

102 UC and 376 CD patients were analyzed. In UC patients surgery was performed for failure of medical therapy in 54%, complications in 28.4%, cancer or dysplasia in 10% of cases, 83.3% elective procedures. 30.4% ileo-anal pouch, 30.4% total procto-colectomies with definitive ileostomies, 32.4% total colectomies with ileo-rectal anastomosis, 6.8% segmental resections, were performed. In CD patients surgery was performed in 21% for medical therapy failure, in 79% for complications. 53.4% of patients were submitted to 1 operation, 84% elective procedures. Reoperations were performed in 46.6% of patients, 70.3% elective procedures. In the first operation bowel resection was performed in 79.1%, stricturoplasty in 14.3%; in the subsequent operations bowel resection 62.8%, stricturoplasty 21.7%, increasing number of temporary or definitive ileo-stomies.

CONCLUSIONS

Collaboration between gastroenterologists and surgeons is necessary to obtain optimal results, reducing the incidence of emergency surgery, and complications. The short period observed between diagnosis and operation (21.4 months) is due to the increasing tendency of gastroenterologists to anticipate a surgical procedure when young patients with a chronic disease need a prolonged medical therapy.

Biological effect of the Planktothrix sp. FP1 cyanobacterial extract

Cyanobacteria are common and potentially harmful inhabitants of freshwater and marine environments worldwide. Some waterbloom-forming cyanobacteria are toxic and they may cause animal death and adversely affect human health. A filamentous freshwater cyanobacterium, Planktothrix sp. FP1, was found to be responsible for a toxic algal bloom in Lake Varese (Italy) during August of 1997. In the present study, the biological effects of the Planktothrix sp. FP1 cell extract on Xenopus embryos and on human Peripheral Blood Mononuclear Cells (PBMC) were investigated. FETAX (Frog Embryo Teratogenesis Assay-Xenopus) showed that the cyanobacterial extract had no teratogenic potential, though embryotoxicity was detected (LC(50) 2.944g/l wet weight). The same extract inhibited the proliferation of PBMC stimulated in vitro by phytohemagglutinin (PHA), and strongly interfered with the production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma).

[Intestinal carcinoma in Crohn's disease. Report of four cases and review of the literature]

BACKGROUND

Increasing numbers of intestinal carcinomas in patients affected by Crohn's disease have been reported by several authors, even if the strength of this associations (age, longstanding of the disease, its characteristics and distribution) still has to be elucidated.

METHODS

From January 1992 to July 2000, 130 patients with Crohn's disease were submitted to surgery.

RESULTS

Four patients showed an associated intestinal carcinoma at operation, in 3 cases located in the ileum, and in 1 case in the colon. Patients' mean age was 54 years. Mean duration time of the Crohn's disease was 7 years. One patient died 3 months after surgery for disseminated peritoneal carcinomatosis, whereas 3 patients are still alive with malignancy free at 5, 8, and 11 years after the tumor resection.

CONCLUSIONS

These results suggest the difficulty in recognizing patients with Crohn's disease who are at risk for intestinal carcinoma. Longstanding disease, previous intestinal exclusion surgery, enterocutaneous or other types of fistulas should be considered for the development of cancer. Therefore, the prognosis may be good if early diagnosis and treatment are made.

Ecotoxicological soil evaluation by FETAX

The frog embryo teratogenesis assay-Xenopus (FETAX) is a powerful and flexible bioassay that makes use of the embryos of the anuran Xenopus laevis. FETAX satisfies the requirements of low cost, reliability and reproducibility and, thanks to its three endpoints (i.e., mortality, teratogenicity and growth inhibition) can detect the xenobiotics that affect embryonic development. In this paper, we have used FETAX to evaluate samples of soils collected in an oil-contaminated area. Embryos were exposed directly to the soil to be tested. Particular attention was devoted to provide a statistical procedure for analysing mortality and malformation data as well as growth retardation.

Development of rat embryos cultured in serum from diabetic rats

Experimental studies carried out in vitro suggest a role of oxidative stress in diabetes-induced embryopathies. Glutathione is the main defense against free radicals in embryonic as it is in adult tissues. In this experiment, using postimplantation whole-embryo culture, we analyze: (1) the effects of serum from streptozotocin-induced diabetic rats on embryonic development and on glutathione distribution between the yolk sac and embryonic tissues and (2) the role of glutathione in preventing embryopathies (using the inhibitor of glutathione synthesis buthionine sulfoximine). Our data show that in rat embryos cultured in diabetic serum, the only observed effects are at the yolk sac level. No effects on the glutathione content were observed. The addition of buthionine sulfoximine reduced the glutathione content and produced signs of developmental delay in embryos cultured in diabetic serum, suggesting a role of the oxidative stress in producing diabetes-related embryotoxicity.

In vitro teratogenic potential of two antifungal triazoles: triadimefon and triadimenol

The teratogenic potential of two antifungal triazoles (Triadimefon and Triadimenol) has been investigated in vitro by the rat postimplantation whole embryo culture method. Rat embryos 9.5 d old were cultured for 48 h in rat serum with Triadimefon (12.5-250 microM) or Triadimenol (6.25-125 microM) and then examined. Some embryos exposed to Triadimenol (6.25-125 microM) were cultured for 12 extra hours in control serum to improve their developmental degree and then immunostain cranial nerves and ganglia. The exposure to the highest doses of triazoles only moderately reduced some morphometrical developmental parameters. By contrast, 25-250 microM Triadimefon and 25-125 microM Triadimenol induced specific concentration-related teratogenic effects at the level of first and second branchial arches. After immunostaining, embryos exposed to 12.5-125 microM Triadimenol showed specific cranial nerve and ganglia abnormalities. The possible implication of neural crest cell alterations on triazole-related abnormalities is discussed.

Morphological alterations induced by sodium valproate on somites and spinal nerves in rat embryos

The antiepileptic drug valproic acid is a well-known teratogenic agent; its main target organ is the neural tube, though skeletal malformations have also been described. In our recent work, respecifications of vertebrae were described in rat fetuses after treatment with 400 mg/kg of sodium valproate at specific somitogenic stages. The observed malformations were stage-dependent. Morphological segmental respecification was observed at the level of segments in formation at the moment of exposure and at the level of more posterior segments. Recently, specific alterations in the development of cranial nerves and ganglia were described in mouse embryos after in vitro exposure to VPA. The aim of the present work was to analyze dysmorphogenetic effects of VPA on embryonic metameric structures: somites, spinal and cranial nerves, and ganglia. Sodium valproate (400 mg/kg) was subcutaneously injected at specific gestational times corresponding to embryonic stages: presomitic or at about 2, 6, 10, 14, 18, or 22 somites. Females were sacrificed on the day 12 post coitum, and embryos were examined. Morphological examination of somites was performed by staining with acridine orange. Morphological examination of nerves and ganglia was performed by immunostaining, using monoclonal antibodies to the 160-kD neurofilament protein. No abnormalities were observed in the cranial nerves and ganglia. Specific and stage-dependent alterations were observed both at the level of the somites and at the level of the spinal nerves. The following characteristic malformations were observed: fusions, duplications, and reductions of somites and corresponding spinal nerves and ganglia. Our morphological data suggest a morphogenetic action of VPA at the level of the axial segments, with a possible respecification of the identity of the interested segments and their derivatives.

Postcoital antifertility activity of aminoalcohols

Previously, postcoital antifertility effects of a number of aminoalcohols, including 2-(isopropylamino)-ethanol, have been demonstrated in rodents. In this experiment, we compared the antifertility activity of 2-(isopropylamino)-ethanol to the following analogs: hydroxyethylpiperidine, hydroxyethylpiridine, hydroxyethylpirrolidine, and hydroxyethylpirrolidone. Female rats were gavaged on Days 0 through 5 of gestation with 0.7 mmol/kg/d of these substances. Only 2-(isopropylamino)-ethanol and hydroxyethylpirrolidine showed a strong antifertility activity: females treated with 2-(isopropylamino)-ethanol had no signs of implantation, whereas those treated with hydroxyethylpirrolidine had 100% early resorptions. Treatments with these two substances during the periimplantation period (Days 4 and 5) produced 100% early resorptions. Histologic examination of the implantation sites showed signs of embryonic degeneration starting from Day 6.5 of gestation. The flushing of the uteri of females treated with 2-(isopropylamino)-ethanol on Days 0 through 3 post coitum showed 78% of the embryos at the stage of 1 to 3 blastomeres, whereas the embryos of females treated during the same period with hydroxyethylpirrolidine were normal blastocysts. Therefore, 2-(isopropylamino)-ethanol and hydroxyethylpirrolidine are able to kill embryos during the early implantation stages, whereas 2-(isopropylamino)-ethanol is also able to stop the development of preimplantation embryos.

Stage-dependent skeletal malformations induced by valproic acid in rat

In this work we study the skeletal teratogenic response in rats exposed to NaVP at different embryonic stages. Crl:CD female rats were treated subcutaneously with 400 mg/Kg b.w. NaVP at presomitic stage (group II) or nearly at 2, 6, 10, 14, 18 or 22 somites (groups III-VIII). The females on group I were treated with saline and served as controls. No treatment-related effects were observed at the level of resorptions, live fetuses and fetal or placental weight. The skeletal examination showed characteristic patterns of malformations strictly related to the period of treatment. In particular, groups II and III showed a significant increase of alterations of cervical vertebrae (mainly 1st to 3rd segment) and a decrease of the frequency of extra lumbar ribs in comparison to control. Group IV showed severe abnormalities localized at the 4th to 7th cervical segment and at the level of the 1st and 2nd thoracic segments, including duplications of thoracic segments 1, 2 or 3. The fetuses of group V were characterized by several alterations of the thoracic segments distributed without a clear specificity. In group VI, the thoracic region was also affected with some specificity at the level of the segments 4th to 9th; in group VII, last thoracic and lumbar segments were affected (mainly duplications) and in group VIII only lumbo-sacral abnormalities were recorded. These results confirm the specific effect of NaVP at the level of the axial skeleton and suggest a possible interaction with the expression of genes identifying the vertebral segments.

[Trans-umbilical cholecystectomy: a new laparoscopic cholecystectomy technique. Description of the technique and preliminary results]

The aim of videolaparo-cholecystectomy is to achieve a good results with minimal surgical trauma. Recently there has been an evolution of this technique toward the progressive reduction of trauma with an improvement of the results, also from the aesthetical point of view. In this article we describe our new videolaparo-cholecystectomy technique. Trans-umbilical videolaparo-cholecystectomy represents a variant of the traditional technique. This new method allows the operation to perform with only two trocars positioned in the peritoneum cavity through only one umbilical incision. The technical innovation of this method consists of the substitution of the others trocars, utilized in the traditional technique, with an equal number of trans-parietal suspension wires. Up to now, we have given 95 patients this kind of operation being successful in 67% of the cases. We think that this new technique, requiring as it does only standard laparoscopic instruments, is in accordance with the philosophy of mini-invasive surgery. The suspension wires are responsible for minimal bile spreading which is not an important complication if the surgeon performs an accurate and through cleaning of the abdominal cavity at the end of the surgical procedure. The patient better accepts this technique because of its better aesthetical results. In spite of this there should be more evaluable data about trans-umbilical videolaparo-cholecystectomy especially about the incidence of post-operatory complications.

Differential and tissue-specific regulation of (pro)insulin and insulin-like growth factor-I mRNAs and levels of thyroid hormones in growth-retarded embryos

The control of embryonic growth in vertebrates appears to rely on the orchestrated action of several families of growth factors and hormones. The contribution of insulin-like growth factor (IGF-I) to prenatal growth regulation is better established in mammals than in other vertebrate species. The status of (pro)insulin gene product(s) in the pancreas and non-pancreatic tissues may be another important contribution to embryonic growth signals. We have characterized tissue sources of IGF-I gene and (pro)insulin gene mRNAs in normal chicken embryogenesis and their changes in a model of avian growth retardation. We studied, by a highly sensitive reverse-transcription coupled to polymerase chain reaction (RT-PCR), the expression of IGF-I and (pro)insulin genes in brain, pancreas, liver and eye in embryos from late organogenesis (E8) to late development (E17); hatching is at E20-21, a period of fast embryonic growth. In brain, pancreas and eye, growth-retarded embryos had lower IGF-I mRNA expression. In contrast, in the liver, little IGF-I mRNA was found during normal embryogenesis, but some early induction occurred in E17 growth-retarded embryos. (pro)insulin gene expression was much lower in absolute levels in non-pancreatic tissues than in pancreas. However, it was developmentally regulated in brain, liver and eye. The growth-retarded, IGF-I-deficient embryos had an increased expression of (pro)insulin mRNA in the brain. While IGF-I treatment of growth-retarded embryos increased their serum IGF-I values, only partial recovery of embryonic weight was obtained. Since abnormalities in other hormones may contribute to the failure of systemic IGF-I to reverse the retarded phenotype, thyroid hormones (T3 and T4) levels were determined in liver, brain and eye. They were markedly altered only in the liver of growth-retarded embryos, where an increase in thyroid hormone content was observed. We conclude that, in chicken embryos and possibly other vertebrates, normal growth may implicate multiple hormones, including the concerted action, endocrine/paracrine, of IGF-I and (pro)insulin gene products.

Glutathione status in diabetes-induced embryopathies

The mechanism involved in diabetes-induced embryotoxicity is still unclear. Mitochondrial alterations probably produced by oxidative stress have been described in embryos developing in a diabetic environment. Furthermore, oxygen radicals-scavenging enzymes can reduce the embryotoxic effects induced by diabetic conditions. In this work we tried to test if glutathione (GSH), a tripeptide implicated in cellular protection against reactive oxygen species, is involved in diabetes-related embryotoxicity. Rat embryos were explanted on day 11 on gestation from normal and from streptozotocin-diabetic mothers. The embryos were examined morphologically, then protein, DNA and GSH were determined both in embryos and in their visceral yolk sacs. The embryos explanted from diabetic mothers showed signs of developmental retardation and 16% were morphologically abnormal. GSH content was reduced in these embryos in comparison to control, but the GSH/protein in the visceral yolk sacs of conceptuses explanted from diabetic mothers was higher than in control visceral yolk sacs. Our hypothesis is that the reduction of embryonic GSH is a consequence of the alteration in GSH transport across the yolk sac endodermal cells damaged by diabetic conditions. The observed reduction in embryonic GSH could reduce the protection against the oxidative stress condition described in diabetic pathology.

Teratogenic effects of sodium valproate in mice and rats at midgestation and at term

This experiment was carried out with the aims of comparing the embryotoxic potential of valproic acid (VPA) in rats and mice, better defining the malformation pattern in these species, and comparing the embryotoxic effects detectable in mid-pregnancy to those observed in fetuses at term. Pregnant CD:Crl rats were treated subcutaneously (s.c.) at 08:00, 16:00, and 00:00 on day 9 of gestation with 0, 150, or 300 mg/ kg VPA; pregnant NMRI mice were treated s.c. at 00:00 on day 7 of gestation, and at 08:00 and 16:00 on day 8 of gestation with 0,75, 150, or 300 mg/kg VPA. Groups of females were killed on day 9 (mice) or day 11 (rats) of pregnancy and their embryos were carefully examined under a dissecting microscope. The remaining females were killed 1 day before parturition and their fetuses were examined for external, visceral, and skeletal malformations. A very high frequency (84%) of malformed embryos was recorded in the group of mice treated with 300 mg/kg, including open brain folds (73%), somite defects (36%), and heart malformations (20%). The rat embryos were less sensitive: only 43% of them were malformed after treatment with 300 mg/ kg, however, the pattern of malformations was quite similar to that observed in mice. The treatment with 150 mg/kg produced about 32% malformed embryos in mice and only 8.5% in rats. More than 84% of mouse fetuses from mothers treated with the highest dose showed a severe form of exencephaly. The axial skeleton was also severely affected. The postimplantation loss reached 52%. Exencephaly and skeletal malformations were also recorded in mouse fetuses from mothers exposed to 150 mg/kg. The dose of 75 mg/kg was without effects. Exencephaly was not observed in rat fetuses at term. In this species the axial skeleton was the most severely affected region at 300 mg/kg, while the lowest dose produced only sporadic malformations. These results confirm that the mouse is the more sensitive species for the teratogenic effects of VPA. Furthermore, it has been shown that, in both species, the axial skeleton is a system which is very sensitive to the teratogenic effects of VPA. The observed alterations show a possible link between axial specification and VPA and suggest further studies of embryos exposed to VPA for the expression of genes controlling the identity of vertebral segments.

Tri-iodothyronine directly affects rat Sertoli cell proliferation and differentiation

The addition of physiological concentrations (1 nM) of tri-iodothyronine (T3) to the culture medium of Sertoli cells from prepubertal (8-day-old) rats stimulated both protein synthesis (+55%) and lactate (+50%) production, while it inhibited DNA synthesis (-30/35%) and aromatase activity (-45/50%); insignificant T3-dependent effects were observed in cultured Sertoli cells from midpubertal (28-day-old) rats. These data suggest an age-dependent role for thyroid hormone in promoting and maintaining Sertoli cell differentiation at puberty; more-over, the hormone is involved in the regulation of Sertoli cell proliferation. The present study validates the role of Sertoli cells as a specific target for T3 action at the testis level; it also demonstrates the existence of an early and critical direct influence of thyroid hormone on Sertoli cell proliferation and functional maturation.

In vitro development of rat embryos obtained from diabetic mothers

Rat embryos of 9.5 or 10 days of gestation were removed from control or streptozotocin-diabetic mothers and cultured in normal rat serum (180 mg% glucose) or in diabetic serum (600 mg% glucose). The development of control embryos in normal serum was adequate. Embryos from normal mothers cultured in diabetic serum showed signs of developmental retardation. The development of embryos obtained from diabetic mothers was severely impaired, regardless of the gestational age or the culture medium. These results suggest that a diabetic maternal milieu produces irreversible effects in the embryo very early in gestation.

Follow-up study on the effects of thyroid hormone administration on androgen metabolism of peripubertal rat Sertoli cells

The inhibitory effect of triiodothyronine (T3) given in early postnatal life on Sertoli cell proliferative activity, leading to their precocious terminal differentiation, has been demonstrated previously. However, data concerning the role of thyroid hormone on androgen metabolism of Sertoli cells during the same period are still lacking. In this study we performed a time-course investigation on the effects of T3 treatment on testosterone metabolism in Sertoli cells isolated from 2-, 3- and 4-weeks-old euthyroid rats. Triiodothyronine (3 micrograms/100 g body wt) was given ip., during the last week prior to sacrifice. Sertoli cells from all animal groups initially were cultured under basal conditions during the first 24 h and subsequently in the presence of testosterone (0.5 mumol/l) with or without T3 (1 nmol/l) for an additional 24 h. This treatment given to 2-week-old animals resulted in reduced testicular growth. As far as androgen metabolism is concerned, T3 in vivo and in vitro treatment in 2- and 3-week-old animals induced a lowering of dihydrotestosterone + 3 alpha-diol with an enhancement of the two other 5 alpha-reduced androgens. The effect was much less pronounced in the oldest group. In both 2- and 3-week-old treated rats a marked reduction of oestradiol was observed, which indicates an inhibition of aromatase activity, mainly in younger animals. This enzyme has been reported to be extremely active in Sertoli cells of rats (of the same strain) between the age of 5 and 20 days, but it decreases rapidly thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of thyroid hormone on androgen metabolism in peripuberal rat Sertoli cells

The aim of the present study was to investigate the influence of thyroid hormones on androgen metabolism in Sertoli cells isolated from 3- and 4- week-old rats. Hypothyroidism was induced by the oral administration of 0.025% methimazole (MMI) from birth until the rats were killed at 3 and 4 weeks of age. Half of the MMI-treated animals were injected i.p. with L-triiodothyronine (T3 3 micrograms/100 g body weight) during the last week before death. Sertoli cells from all groups were initially cultured under basal conditions for the first 24 h and subsequently in the presence of testosterone with or without T3 for an additional 24 h. Hypothyroidism was associated with severe impairment of body as well as testicular growth. Indeed, body and testicular weights were similar in 4-week-old hypothyroid animals to those in 3-week-old control rats. Testosterone metabolism in Sertoli cells isolated from 3- and 4-week-old hypothyroid rats was mainly expressed by the lowering of 5 alpha-dihydrotestosterone + androstane 3 alpha, 17 beta-diol and an enhanced formation of 5 alpha-reduced steroids with poor androgenic properties (e.g. 5 alpha-androstane, 3, 17 alpha-dione (androstanedione), 5 alpha-androstane, 3-ol-17-one (androsterone)). Treatment of the same group of animals with T3 in vivo and in vitro did not influence the pattern of 5 alpha-reductase steroids substantially. The most striking finding in the Sertoli cells of 3-week-old hypothyroid rats was the dramatic enhancement of oestradiol formation which persisted to a lesser extent 1 week later.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of thyroid status on the oxidative capacity of Sertoli cells isolated from immature rat testis

Our previous studies indicate the Sertoli cell as a target for thyroid hormone action at testis level. In the present study we evaluated the effect of thyroid hormone on Sertoli cell oxidative capacity measured by specific cytochrome oxidase (COX) activity and intracellular adenosine triphosphate (ATP) content. Sertoli cells were isolated from 21-day-old rats. Hypothyroidism, induced from the day of birth by administration of 0.025% methimazole, was characterized by a severe delay of body and testis growth and resulted in a lower COX activity (-40%, p < or = 0.01) and a lower ATP content (-35%, p < or = 0.01) by isolated Sertoli cells. Administration of triiodothyronine (10 micrograms/100 g body wt on alternate days) to hypothyroid rats improved body and testis growth and restored both COX activity and ATP content. The presence of high-affinity, low-capacity binding sites for triiodothyronine in Sertoli cell mitochondria also was demonstrated. This study, unlike that carried out on the whole testis from adult rats, demonstrates that thyroid hormone affects the energy metabolism of Sertoli cells from midpubertal rat testes.

The protective effects of N-acetyl-L-cysteine against methyl mercury embryotoxicity in mice

N-Acetyl-L-cysteine (NAC) has been widely used in the protection against the toxic effects produced by several chemicals because of its radical scavenger properties and because NAC is a precursor of glutathione, one of the most important intracellular defenses against oxidants. The aim of this investigation was to verify the potential protective activity of NAC against the well-known embryotoxicity induced by methyl mercuric chloride (MMC) in mice. Three experimental approaches were carried out. In the first investigation, acute treatment of MMC (25 mg/kg po) was given in CD female mice on Day 10 of pregnancy, and was followed immediately and/or after 24, 48, and 72 hr by administrations of NAC (800 mg/kg i.v.). The embryolethal effects caused by MMC poisoning were completely antagonized by just a single administration of NAC, while the incidence of palatoschisis was reduced in relation to the number of NAC administrations. In the second experiment MMC was chronically gavaged (3 mg/kg/day po) during the period of organogenesis on Days 5 to 14 of gestation. During the same period of time some of these females were also exposed to 1% NAC dissolved in drinking water. MMC poisoning reduced the body weight of viable fetuses and induced many cases of palatoschisis. The body weight of fetuses from MMC-poisoned mothers treated with NAC was improved and the incidence of palatoschisis was in the normal range. In the last experiment the treatment with NAC (400 mg/kg i.v., during the period of organogenesis) drastically reduced the severe embryolethality induced by MMC (6 mg/kg/day po) administered during the same period of time.(ABSTRACT TRUNCATED AT 250 WORDS)

Thyroidal regulation of nuclear tri-iodothyronine receptors in the developing rat testis

Previous work has demonstrated that thyroid hormones influence testis development. Specific receptors for tri-iodothyronine (T3) have been demonstrated in Sertoli cells. The aim of the present study was to examine the possible effect of thyroid hormone on its own receptor during pubertal development by evaluating the influence of thyroid status on T3-binding capacity, -binding affinity and receptor occupancy in nuclei isolated from immature rat testes. The binding capacity for T3 of nuclei from rat testis significantly decreased during pubertal development, being 375 +/- 32, 117 +/- 15 and 44 +/- 7 fmol/mg DNA in 7-, 21- and 35-day-old rats respectively, whereas the affinity of binding, as evaluated by the dissociation constant (Kd), did not change. Early induced hypothyroidism significantly affected the time-course of the postnatal decline of nuclear T3 receptors in the testis. At 21 days of age, the binding capacity for T3 in the testis of methimazole-treated rats was significantly higher with respect to euthyroid controls, being 173 +/- 21 and 117 +/- 15 mol/mg DNA respectively, while the Kd was unaffected. T3 replacement therapy completely prevented changes in T3 receptor number induced by hypothyroidism without modifying the Kd. Our results indicate that nuclear T3 receptors in the developing rat testis are modulated by thyroid hormone.

Effects of diets with different content in protein and fiber on embryotoxicity induced by experimental diabetes in rats

Three groups of streptozotocin-diabetic rats were maintained during pregnancy on three hyperproteic diets with different protein contents. These differences were compensated by an equal quantity of fiber (group 1: protein 55.0%, fiber 4.5%; group 2: 45.0%, 14.0%; group 3: 35.0%, 24.0%). Three groups of nondiabetic pregnant rats were fed with the same diets and served as control. The differences of the daily protein intake among the diabetic groups were less pronounced than those expected on the basis of the diet composition, and the embryopathic effects (reduced fetal weight, increased in malformation and resorption rate) were not statistically different among the three groups of diabetic animals. The frequency of congenital malformations was higher than that observed in a previous experiment in diabetic rats maintained on a standard diet, but much lower than that observed in animals fed on a purified, fiber-poor, normoproteic diet. When the caloric intake of the diabetic rats in the different groups was determined it was found to be similar for all of them and also similar to the caloric intake of the rats given a standard nonteratogenic diet (in previous experiments), while the rats maintained on a normoproteic, teratogenic diet increased their caloric intake. These results seem to indicate that the diet composition greatly influences the intake of food and calories of pregnant diabetic rats and this may play a role in modulating the embryopathic effect of diabetes.

L-thyroxine and 3,5,3'-triiodothyronine concentrations in the chicken egg and in the embryo before and after the onset of thyroid function

The concentrations of T4 and T3 were measured by specific RIAs in chicken embryonated eggs and embryonic tissues before (at 4 and 6 days of incubation) and after the onset of thyroid function (at 10-20 days). All samples were submitted to extensive delipidation and purification. T4 and T3 were found in the yolk, as described by others, and also in the egg white, although at lower concentrations. The initial total maternal supplies per egg are 67 ng T4 and 30 ng T3 in the yolk, and 2.4 ng T4 and 1.9 ng T3 in the egg albumen. Whole 4-day-old embryos contained a total of 2.48 pg T4 and 0.65 pg T3. The head (mostly brain) of 6-day old embryos contained 4.1 pg T4 and 4.6 pg T3; T4 (but not T3) was also measurable in the carcass. The concentrations of T4 increased progressively between 10 and 20 days in the brain, eyes, liver, and heart; they were especially high in the eyes (4.8 ng/g) and liver (8.2 ng/g) at 20 days. T3 levels increased markedly in the brain (to 5.1 ng/g at 20 days) and less markedly in the eyes (to 1.3 ng/g) and heart (to 1.6 ng/g), but were low and stable in liver up to 18 days (0.3 ng/g), after which there was a sudden increase to 1.4 ng/g at 20 days. Iodothyronines are, therefore, available to the chick embryo throughout development both before and after the onset of thyroid function. T3 concentrations, especially in the brain, reach much higher levels than previously inferred from the low plasma T3 levels. These findings show similarities with those described for the fetal rat.

HPLC analysis of free amino acids and amino acids of total proteins in cultured cells: an application to the study of rat Sertoli cell protein metabolism

A simple, rapid and, sensitive HPLC method, coupled with fluorometric detection, has been worked out and employed to determine the intracellular free amino acid concentrations and the amino acid composition of total proteins in rat Sertoli cell primary culture. Sertoli cells were isolated enzymatically from testes of 20- and 28-day-old rats and cultured at 32 degrees C in Eagle's minimum essential medium. On the second day of culture, cell monolayers were quickly rinsed with ice-cold saline, immediately frozen in liquid nitrogen, accurately harvested, and homogenized in 10% trichloroacetic acid. Tissue free amino acids were determined in the acidic soluble fraction following neutralization, while the precipitate was hydrolyzed for the evaluation of the fractional content of amino acids into total proteins. Amino acid samples were derivatized with o-phthaldialdehyde/3-mercaptopropionic acid and resolved by a linear one-step acetonitrile gradient in 12.5 mM sodium phosphate buffer, pH 7.2, employing a 5-microns particle size reversed-phase column. Fluorescence was monitored with excitation at 330 nm and emission at 450 nm. Under these conditions all major physiological amino acids could be satisfactory separated, identified, and subsequently quantified with the aid of standards. The run time was about 50 min; the linearity was excellent over a large range of concentrations (1-800 pmol) and the lower limit of sensitivity appeared to be 0.5 pmol. This method permits us to demonstrate age-dependent modifications in the intracellular amino acid pool and to adequately evaluate the process of protein synthesis in cultured Sertoli cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ethanol and acetaldehyde on rat embryos developing in vitro

Rat embryos were explanted on Days 9.5 or 10 of gestation and cultured for 48 to 30h, respectively, in rat serum containing 0, 3, 6, 9 mg/ml of Ethanol (Eth); 0, 10, 20 micrograms/ml of Acetaldehyde (Ach); 3 mg/ml Eth + 10 micrograms/ml Ach. At the end of the culture period the embryos were evaluated for vitality, and scored. Some of them were also examined histologically. Embryos exposed to Eth from Day 9.5 showed a dose-related growth retardation associated with a high frequency of malformations (open neural tube, heart defects, branchial arch hypoplasia). The exposure of 9.5-day embryos to 20 micrograms/ml Ach resulted in 100% embryolethality, whereas 10 micrograms/ml induced growth retardation and teratogenic effects. When 10-day embryos were exposed to 3 mg/ml Eth or 10 microliters/ml Ach no effects were observed, but the highest levels of Eth produced a moderate growth retardation and morphologic defects. Exposure to 20 micrograms/ml Ach induced hypoplasia of the first arch, but did not alter the score value. The histologic examination of these embryos revealed severe lesions at the level of the neuroepithelium and of the branchial mesenchyma. Similar effects were observed in embryos exposed simultaneously to 3 mg/ml Eth and 10 micrograms/ml Ach. These results should make us reevaluate the role of Ach in the Eth-induced embryopathies.

[Effect of insulin-like growth factor I (IGF-I) on Sertoli cell metabolism in the pubescent rat]

The influence of Insulin-like Growth Factor I (IGF-I) on some metabolic functions of Sertoli cells from peripubertal rats was investigated. Sertoli cells were isolated from the testes of 24-day-old animals and cultured at 32 degrees C in Eagle's MEM with or without 1 nM IGF-I. Sertoli cells cultured in the presence of IGF-I showed increased nuclear RNA polymerase activity (+80%) and augmented protein synthesis (+50%).

[Nuclear triiodothyronine receptors in the testis of the growing rat are regulated by the thyroid status]

The effects of thyroid status on the binding capacity, association constant (Ka) and receptor occupancy during postnatal rat testis development were evaluated. Hypothyroidism (induced by oral administration of 0.05% methimazole from the day of birth) increased the total T3 binding capacity in the testis, retarding the normal developmental decrease in T3 receptor number (mean maximal binding capacities estimated by Scatchard analysis for 21-day-old eu- and hypothyroid rats were 117 and 173 fmol/mg DNA, respectively). The rat thyroid status also affected the percentage of T3 receptor occupancy but not the affinity of binding (as measured by Ka). The postnatal developmental changes in T3 binding capacity induced by hypothyroidism were completely reversed by T3 replacement. These results suggest that T3 nuclear receptors in the developing rat testis are modulated by thyroid hormones.

Diet composition modifies embryotoxic effects induced by experimental diabetes in rats

Despite improvements in prenatal care, the incidence of congenital malformations in diabetic pregnancies is still 3-4 times higher than in normal pregnancies. These defects could be attributed to alterations of intrauterine environment due to disorder of the maternal metabolism. If this were true, the quality of food could play a role in diabetes-induced embryotoxicity. To check this hypothesis, female CD rats were made diabetic by injecting intravenously 50 mg/kg of streptozotocin 2 weeks before mating. From the first day of pregnancy they were divided into three groups and maintained on the following diets: (1) standard diet (Italiana Mangimi); (2) purified high protein diet (protein 55%, carbohydrates 25.5%, fat 7.5%, fiber 4.5%, ash 7.5%); (3) purified normoprotein diet (protein 19%, carbohydrates 62.5%, fat 7.5%, fiber 4%, ash 7%). Nondiabetic pregnant females fed with standard diet served as negative control. No significant differences were observed in blood glucose levels among the groups (range 410-500 mg/dl). The group fed on normoprotein diet showed at term of pregnancy: (1) higher rate of resorptions; (2) lower fetal weight; (3) higher frequency of major malformations than the groups fed standard and hyperproteic diets. Although we are not able at this time to discriminate between a protective effect of a diet with a high protein content and a disruptive effect of a diet containing high quantity of carbohydrates, the results of this trial support the hypothesis of a fuel-mediated teratogenesis in diabetic pregnancy.

The effect of L-acetylcarnitine on some reproductive functions in the oligoasthenospermic rat

The effect of L-acetylcarnitine (LAC) on some parameters of male reproductive function was studied on rats made oligoasthenospermic with dibromochloropropane (DBCP). DBCP depresses sperm count and motility. After one injection of the drug, LAC induces a recovery of both sperm count and motility but after two injections it is ineffective. This effect is also shown visually by microscopic examination of seminiferous tubules. Among the enzymatic activities evaluated as biochemical markers of testicular function both lactate dehydrogenase and NADPH-cytochrome P 450-reductase increased significantly (P less than 0.05) after treatment with LAC in normal rats. LAC also stimulates testosterone production. It is suggested that LAC may affect testicular function.

Influence of hypothyroidism on in-vitro testicular steroidogenesis in adult rats

The influence of hypothyroidism on testicular steroidogenesis was investigated by evaluating the production of testosterone and its precursors by isolated testes from adult male rats. Animals were made hypothyroid starting from the 4th week of life either by daily oral administration of 0.1% methimazole (MMI) or by surgical thyroidectomy (TZ). Half of the thyroidectomized rats were i.p. injected with 3 gamma T3/100 g body weight on alternate days during the last three weeks before sacrifice. Hypothyroidism is associated with a severe retardation of body growth, which appears more marked in thyroidectomized than in MMI treated rats; no significant variations in testis weight are observed. Administration of T3 does not completely restore body weight. A significant decrease in the "in vitro" production of testosterone and its precursors by testes isolated from hypothyroid rats is observed. This effect is more evident in thyroidectomized rats where a marked drop in the "in vitro" production of some testosterone delta 4 precursors is associated with the increase in DHEA/delta 4 ratio. T3 injection to thyroidectomized rats only partially restores the "in vitro" testosterone production. Results suggest that as the degree of hypothyroidism became more severe, the rate of testosterone production decreases and testicular steroidogenesis changes from the delta 4 to delta 5 metabolic pathway as a consequence of the impairement of 3-beta-ol-dehydrogenase activity.

Thyroid hormone stimulates the production of insulin-like growth factor I (IGF-I) by immature rat Sertoli cells

The effects of thyroid hormone on insulin-like growth factor I (IGF-I) production by Sertoli cells isolated from immature rats have been investigated. In Sertoli cells from hypothyroid rats the production of IGF-I was significantly lower than in controls and was greatly stimulated by the administration of triiodothyronine (T3) in vivo. The in vitro addition of physiological doses of T3 (1 nmol/l) significantly increased the production of IGF-I by cultured Sertoli cells indicating a direct action of the hormone on local IGF-I production. Our results suggest the involvement of IGF-I in the thyroid hormone-dependent maturation of testicular function.

Congenital malformations in offspring of diabetic rats: experimental study on the influence of the diet composition and magnesium intake

In spite of improvements in the treatment of diabetes, the risk of congenital malformations in diabetic pregnancy is three to four times higher than in normal pregnancy. This might be due to the metabolic abnormalities of diabetic pregnancy that also affect mineral metabolism. Since diabetes can lower both maternal and fetal blood Mg levels, and Mg deficiency has been shown to be teratogenic in laboratory animals, we decided to investigate which effects Mg deficiency would have in inducing embryopathy in diabetic animals. Female CD rats were divided into six groups. Groups 1 and 2 were fed a standard diet (Mg content 4,200 ppm), groups 3-6 a purified diet (Mg contents 4,200, 500, 250, or 125 ppm). Groups 2-6 had been made diabetic by an intravenous injection of 50 mg/kg streptozocin 1 week before mating. The rats were killed on day 21 of pregnancy, and the live fetuses were examined for external, skeletal, and visceral malformations. The maternal and fetal blood glucose levels were the same in all diabetic groups. The maternal Mg levels in groups 2 and 3 were the same as in controls, but definitely lower in groups 4-6. Embryotoxicity (embryonic deaths, delayed development, congenital malformations) was higher in the groups fed the purified diet than in group 2, but without a clear relation to the dietary Mg levels. We cannot draw any conclusions about the effects of Mg deficiency in diabetic pregnancy from our results, but they show that the quality of the diet is of major importance in the manifestation of embryotoxicity in diabetes.

Morphogenesis of diabetes-induced congenital cataract in the rat

The eye development of rat fetuses and pups from normal and streptozotocin-diabetic mothers was studied histologically in order to verify the morphopathogenesis of congenital cataract. The first signs of lens alterations were observed in 17-day-old fetuses from diabetic mothers. The fibres swelled up, became hydropic and subsequently degenerated, giving rise to large cysts filled with amorphous material in the middle of the lens. The pathogenic route observed suggests an osmotic disturbance in the physiology of the lens fibres, probably related with an accumulation of some polyols.

Induction of micronuclei and toxic effects in embryos of pregnant rats treated before implantation with anticancer drugs: cyclophosphamide, cis-platinum, adriamycin

To evaluate a possible relationship of maternal exposure to anticancer drugs during the preimplantation period to blastopathies and postimplantation embryotoxicity, CD female rats were injected intraperitoneally on day 3 of pregnancy with 15 and 30 mg/kg of cyclophosphamide (CPA), 2 and 4 mg/kg of Adriamycin (ADR), 3 and 6 mg/kg of cis-platinum (Cis-Pt), or with 5 ml/kg of saline. Blastocysts were collected on day 5 of gestation and evaluated for gross morphology, cell number, and micronuclei. Some females were sacrificed on day 21 of pregnancy in order to evaluate postimplantation embryotoxicity. A reduction in cell number/blastocyst was observed only in animals exposed to Cis-Pt 6 mg/kg; vice versa, a dose-related increase of micronuclei and of blastocysts with micronuclei was found in all groups treated with the anticancer agents. A significant increase of postimplantation loss was recorded in the groups treated with high doses of Cis-Pt and ADR, but no clear signs of teratogenicity were observed.

Dibromochloropropane (DBCP) effects on the reproductive function of the adult male rat

In order to evaluate the effect of dipromochloropropane (DBCP) on reproductive function, groups of male adult Wistar rats were injected subcutaneously with different doses of DBCP. A strictly dose-dependent effect resulting in histological alteration principally toward the seminiferous tubules was observed. Sperm count and sperm motility showed azoospermia or oligoasthenospermia with a significative recovery in the lower dose of DBCP treated rats. Among the enzymatic activities evaluated as biochemical markers of testicular function: LDH was not appreciably affected by the DBCP treatment while GGT and NADPH-cyt P450-reductase significantly enhanced suggesting an induction of the detoxification processes.

Effects of streptozotocin-induced diabetes on fetal development of the rat

The purpose of this study was to determine whether or not in rats with experimentally induced diabetes there is an increased frequency of congenital malformations; data in the literature are not consistent on this point. Virgin CD females rats were injected with 40-50 mg/kg streptozotocin (Stz) before mating (SIBM group) or on the first day of pregnancy (SI1). Both SIBM and SI1 females were divided into two groups according to their blood glucose levels: severely diabetic (SD, greater than 300 mg%) and mildly diabetic (MD, 120-250 mg%). Food and water consumption by the control and MD groups were the same, but the SD females developed polyphagia, polyuria, and polydypsia, which continued to increase throughout pregnancy, as did the blood glucose levels. All the MD females mated and carried to term. In SD females both frequency of mating and fertility were only slightly lower than in the controls. All the females were killed on the 21st day of pregnancy. Pre- and postimplantation losses were the same for diabetic and control rats, but SIBM-SD females ovulated less than other groups. Weights of fetuses of SD dams were lower and blood sugar levels higher than those of the other groups. The placentas of SD rats were significantly heavier and there was cystic degeneration of spongiosa. The incidence of major malformations was minimal (approximately 2%) in fetuses of SD females and there were none at all in controls or MD females. In conclusion, our data are in agreement with those of other investigators who have found that rats with experimentally induced diabetes have smaller fetuses and increased placental weight.(ABSTRACT TRUNCATED AT 250 WORDS)

Embryotoxic effects of 2,3,7,8 tetrachlorodibenzo-p-dioxin administered to female rats before mating

2,3,7,8-Tetrachlorodibenzo-p-dioxin was administered to female rats by gavage for 2 consecutive weeks at daily doses of 0, 0.125, 0.5, and 2 micrograms/kg. After treatment females were caged with untreated males. All dams were killed on Day 21 of gestation. Their reproductive statuses were recorded and live fetuses were examined for external, visceral, and skeletal malformations. At 0.125 micrograms/kg no effects were observed on both maternal and fetal toxicity; 0.5 micrograms/kg reduced maternal weight gain and increased postimplantation loss. At 2 micrograms/kg the following features became evident: reduction of both maternal weight gain and ovulation rate, increase of pre- and postimplantation loss, and fetal growth retardation. Also, malformed fetuses were observed at this dose level.

Embryotoxic effects of 5-hydroxytryptamine during the peri-implantation period in the rat

Administration of 5-hydroxytryptamine creatinine sulphate (5-HT) 5-10-20 mg/kg s.c. to pregnant rats during the preimplantation period (1200 h, Days 1 through 5) did not inhibit implantation. Experiment 2: Administration to pregnant rats during the peri-implantation period (0900 h, Day 6) of 5-HT 5 mg/kg s.c. did not affect implantation or embryo-fetal development. 5-HT 10 mg/kg s.c. produced a significant increase (P greater than 0.01) in the resorption rate (31.8%) and severe cardiovascular or ophthalmic malformations in 5.3% of viable fetuses. 5-HT 20 mg/kg produced a resorption rate (97.2%) virtually incompatible with the continuance of pregnancy. Experiment 3: Histological examination of uterine preparations made from Day 6 pregnant rats sacrificed 6, 24, and 30 h after receiving 5-HT 20 mg/kg s.c. showed, in 30 h post-injection preparations, toxic effects at implantation sites (uterine lumen completely deprived of epithelial layer and filled with cellular debris, and complete degeneration of implanted embryos) but no toxic effects between implantation sites. Experiment 4: Administration of 5-HT 10 mg/kg s.c. to pregnant rats during the postimplantation period (Days 10 and 11) produced a 63.2% resorption rate, a reduction in the mean weight of viable fetuses, and severe malformations in 24% of viable fetuses. The embryotoxic activity of 5-HT may be attributed to its vasoconstrictive action which renders the uterine mucosa or trophoblast ischemic, thus causing irreversible damage to the luminal epithelium at the implantation sites.

Morphogenesis of aortic arch malformations in rat embryos after maternal treatment with glycerol formal during pregnancy

The morphogenesis of the aortic arch system was studied in rat embryos whose mothers had been treated with glycerol formal (GF) during pregnancy. The fetuses were removed from the uterus on days 13-17 of gestation and India ink was injected into their vascular system while they were still alive. The teratogenic effect of GF manifested itself by developmental retardation of the aortic arch system, vessel dilatation and persistence or anomalous regression of embryonic vessels. These conditions result in several aortic arch malformations: right aortic arch, double aortic arch and persistence of the 3rd aortic arch.