A quantitative analysis of germ cells and the histone variants in the testes of vitamin A-deficient rats and during subsequent repletion with vitamin A

A quantitative analysis of the different types of germ cells present in the seminiferous tubules of vitamin A-deficient-retinoate maintained rats revealed that the number of pachytene spermatocytes and spermatogonia was greatly reduced in the deficient rats. Spermatids were virtually absent in the deficient tubules which contained mostly spermatogonia and preleptotene spermatocytes along with the Sertoli cells. There was no change in the number of Sertoli cells present in the tubules of deficient rats as compared to that of normal rats. Following supplementation of retinyl acetate to vitamin A-deficient-retinoate maintained rats, there was an immediate thinning of the germinal epithelium resulting from the sloughing off of the damaged spermatocytes which were beyond repair. However, after 12 days of vitamin A supplementation fresh batch of pachytene spermatocytes started appearing while by day 16 round spermatids could be seen. Analysis of the acid soluble proteins from nuclei on different types of Polyacrylamide gel electrophoretic systems has revealed that the levels of the testis specific histone variants Hlt, TH2A and TH2B, synthesized predominantly in the pachytene spermatocytes were greatly reduced in the testes of retinoate maintained rats. Following supplementation of retinyl acetate for either 4 days or 8 days the levels of these histone variants further decreased which correlated with the decrease in the number of pachytene spermatocytes. However, by day 12 of supplementation onwards, their levels started increasing and reached near normal levels by day 24 of vitamin A-supplementation

Osteopontin is a potential target gene in mouse mammary cancer chemoprevention by Se-methylselenocysteine

BACKGROUND: Se-methylselenocysteine (MSC) is a naturally occurring organoselenium compound that inhibits mammary tumorigenesis in laboratory animals and in cell culture models. Previously we have documented that MSC inhibits DNA synthesis, total protein kinase C and cyclin-dependent kinase 2 kinase activities, leading to prolonged S-phase arrest and elevation of growth-arrested DNA damage genes, followed by caspase activation and apoptosis in a synchronized TM6 mouse mammary tumor model. The aim of the present study was to examine the efficacy of MSC against TM6 mouse mammary hyperplastic outgrowth (TM6-HOG) and to determine in vivo targets of MSC in this model system. METHODS: Twenty mammary fat pads each from female Balb/c mice transplanted with TM6-HOG and fed with 0.1 ppm selenium and with 3 ppm selenium respectively, were evaluated at 4 and 12 weeks after transplantation for growth spread, proliferative index and caspase-3 activity. Thirteen mice transplanted with TM6-HOG in each selenium group were observed for tumor formation over 23 weeks. Tumors from mice in both groups were compared by cDNA array analysis and data were confirmed by reverse transcription–polymerase chain reaction. To determine the effect of MSC on the expression of the novel target gene and on cell migration, experiments were performed in triplicate. RESULTS: A dietary dose of 3 ppm selenium significantly reduced the growth spread and induced caspase-3 activity in mammary fat pads in comparison with mice fed with the basal diet (0.1 ppm selenium). The extended administration (23 weeks) of 3 ppm selenium in the diet resulted in a tumor incidence of 77% in comparison with 100% tumor incidence in 0.1 ppm selenium-fed animals. The size of TM6 tumors in the supplemented group was smaller (mean 0.69 cm(2)) than in the mice fed with the basal diet (mean 0.93 cm(2)). cDNA array analysis showed a reduced expression of osteopontin (OPN) in mammary tumors of mice fed with the 3 ppm selenium diet in comparison with OPN expression in tumors arising in 0.1 ppm selenium-fed mice. A 24-hour treatment of TM6 cells with MSC significantly inhibited their migration and also reduced their OPN expression in comparison with untreated cells. CONCLUSIONS: OPN is a potential target gene in the inhibition of mammary tumorigenesis by selenium

HMGB4 is expressed by neuronal cells and affects the expression of genes involved in neural differentiation

HMGB4 is a new member in the family of HMGB proteins that has been characterized in sperm cells, but little is known about its functions in somatic cells. Here we show that HMGB4 and the highly similar rat Transition Protein 4 (HMGB4L1) are expressed in neuronal cells. Both proteins had slow mobility in nucleus of living NIH-3T3 cells. They interacted with histones and their differential expression in transformed cells of the nervous system altered the post-translational modification statuses of histones in vitro. Overexpression of HMGB4 in HEK 293T cells made cells more susceptible to cell death induced by topoisomerase inhibitors in an oncology drug screening array and altered variant composition of histone H3. HMGB4 regulated over 800 genes in HEK 293T cells with a p-valuePeer reviewe

Se-methylselenocysteine inhibits phosphatidylinositol 3-kinase activity of mouse mammary epithelial tumor cells in vitro

INTRODUCTION: Se-methylselenocysteine (MSC), a naturally occurring selenium compound, is a promising chemopreventive agent against in vivo and in vitro models of carcinogen-induced mouse and rat mammary tumorigenesis. We have demonstrated previously that MSC induces apoptosis after a cell growth arrest in S phase in a mouse mammary epithelial tumor cell model (TM6 cells) in vitro. The present study was designed to examine the involvement of the phosphatidylinositol 3-kinase (PI3-K) pathway in TM6 tumor model in vitro after treatment with MSC. METHODS: Synchronized TM6 cells treated with MSC and collected at different time points were examined for PI3-K activity and Akt phosphorylation along with phosphorylations of Raf, MAP kinase/ERK kinase (MEK), extracellular signal-related kinase (ERK) and p38 mitogen-activated protein kinase (MAPK). The growth inhibition was determined with a [(3)H]thymidine incorporation assay. Immunoblotting and a kinase assay were used to examine the molecules of the survival pathway. RESULTS: PI3-K activity was inhibited by MSC followed by dephosphorylation of Akt. The phosphorylation of p38 MAPK was also downregulated after these cells were treated with MSC. In parallel experiments MSC inhibited the Raf–MEK–ERK signaling pathway. CONCLUSION: These studies suggest that MSC blocks multiple signaling pathways in mouse mammary tumor cells. MSC inhibits cell growth by inhibiting the activity of PI3-K and its downstream effector molecules in mouse mammary tumor cells in vitro

A quantitative analysis of germ cells and the histone variants in the testes of vitamin A-deficient rats and during subsequent repletion with vitamin A

A quantitative analysis of the different types of germ cells present in the seminiferous tubules of vitamin A-deficient-retinoate maintained rats revealed that the number of pachytene spermatocytes and spermatogonia was greatly reduced in the deficient rats. Spermatids were virtually absent in the deficient tubules which contained mostly spermatogonia and preleptotene spermatocytes along with the Sertoli cells. There was no change in the number of Sertoli cells present in the tubules of deficient rats as compared to that of normal rats. Following supplementation of retinyl acetate to vitamin A-deficient-retinoate maintained rats, there was an immediate thinning of the germinal epithelium resulting from the sloughing off of the damaged spermatocytes which were beyond repair. However, after 12 days of vitamin A supplementation fresh batch of pachytene spermatocytes started appearing while by day 16 round spermatids could be seen. Analysis of the acid soluble proteins from nuclei on different types of Polyacrylamide gel electrophoretic systems has revealed that the levels of the testis specific histone variants Hlt, TH2A and TH2B, synthesized predominantly in the pachytene spermatocytes were greatly reduced in the testes of retinoate maintained rats. Following supplementation of retinyl acetate for either 4 days or 8 days the levels of these histone variants further decreased which correlated with the decrease in the number of pachytene spermatocytes. However, by day 12 of supplementation onwards, their levels started increasing and reached near normal levels by day 24 of vitamin A-supplementation

Androgen Binding Protein Levels And Fsh Binding To Testicular Membranes In Vitamin A Deficient Rats And During Subsequent Replenishment With Vitamin A

ABP levels in the testes and epididymides of vitamin A deficient-retinoic acid maintained rats were only 20 and 6% respectively as compared with those in normal rats. The number of FSH receptors in the testes of vitamin A deficient rats, as measured by [^1^2^5I] ovine FSH binding to isolated testicular membranes, was only 40% of that in the testes of normal rats. Supplementation of retinyl acetate to these vitamin A deficient rats for 16 days resulted in restoration of the number of FSH receptors to normal levels. On the other hand, ABP levels were restored to 32 and 34% only in the testes and epididymides respectively

Metoder för aktiv manipulering av vätskedroppar

The deposition of functional materials utilising a jetting head has a large number of applications as can be seen by the growing interest in rapid prototyping. The ability to jet with precision and accuracy for high throughput application is at the core of the jetting technology. If this can be achieved at increasingly large altitudes over the substrate an increased portion of the business application space can be addressed, such as the ability to jet with smaller droplets, the ability to jet on complex PCB configurations, et cetera. A state of the art study is included in this project, which describes different potential methods that could be used for active manipulation of fluid droplets. In this project, two methods have been investigated for active manipulation of fluid droplets that could be implemented on the MY600 Jet Printer. The first method is based on using a converging air flow to focus the droplets towards the centre of a tube and thus reduce error positioning. From the simulations and analyses performed, it was concluded that this method was not suitable for implementation on the MY600 Jet Printer due to the excessively high air flow speed required to correct any misalignments. The second method investigated uses an electrostatic field to affect the positioning of charged droplets. From the performed experiments, it was concluded that the droplets can be affected by the electrostatic field, but that active charging of the droplets is necessary to achieve an adequate force required to correct any misalignments within a reasonable height.Den ständigt växande marknaden för kretskortstillverkning ställer allt högre krav på leverantörer när det kommer till tillverkningshastighet och noggrannhet. Detta är en stor utmaning för Mycronic som ständigt måste förbättra precisionen på sina produktionsrobotar för att behålla och eventuellt stärka sin position inom branschen. Genom att öka höjden från vilken skotten skjuts ifrån, och samtidigt bibehålla precisionen, skulle man kunna öppna nya dörrar för att till exempel minska volymen på skotten för att träffa allt mindre paddar eller skjuta lodpasta på komplicerade kretskort med färdigmonterade komponenter. Under projektet utfördes en undersökning om vilka metoder som idag används för att styra och manipulera droppar. Undersökningen resulterade i idéer på hur problemet kan lösas, vilka presenteras i rapporten. Två metoder har studerats och för att ta reda på om de kan bidra till en ökad precision för MY600 Jet Printer. Den första metoden baseras på ett fokuserande luftflöde där man påverkar kroppens rörelse med ett riktat luftflöde. Uträkningar och simuleringar visade att kraften, som luften verkar med, inte räcker till för de lufthastigheter som var realistiska att implementera. Den andra metoden baserades på fokuseringen av uppladdade droppar med hjälp av elektriska fält. Denna metod uppvisade positiva resultat. Efter ett flertal tester, med olika vätskor, drogs slutsatsen att det skulle vara möjligt att implementera en prototyp där dropparna laddas upp för att sedan fokuseras av ett elektriskt fält inuti en cylinder och på så sätt förbättra noggrannheten

Histological and ultrastructural studies on the effect of vitamin A depletion and subsequent repletion with vitamin A on germ cells and Sertoli cells in rat testis

At the onset of vitamin A [68-26-8] deficiency the testis Sertoli cell-spermatid assocn. was disrupted, resulting in sloughing off of the germ cells from the germinal epithelium. At the acutely deficient stage the seminiferous tubules were left with a single layer of spermatogonia and a no. of giant cells together with disorganized Sertoli cells. Even though B-type spermatogonia and preleptolene spermatocytes were present in the testis of rats maintained on retinoic acid, many of these were in a degenerated state. Peroxidase perfusion studies showed that the tracer penetrated into the lumen of the seminiferous tubules of the mild deficient and that of the retinoic-acid maintained rats while it was mostly concd. at the periphery of the tubules of the normal rat testes, thereby indicating disruption of the Sertoli-Sertoli cell junctional complexes and consequently the blood-testis barrier. Supplementation of the retinoate-fed rats with retinyl acetate led to several changes in the seminiferous tubules within 4 days such as (1) thinning of the germinal epithelium immediately after the supplementation; (2) re-establishment of the Sertoli-Sertoli cell junctional complexes; (3) cannanulation of the lumen of the tubules; and (4) appearance of pachytene spermatocytes. Examn. of the mitotic activity of the spermatogonial compartment revealed marked redn. in the activity in acutely deficient animals while the retinoate-fed rats it was slightly lower than in controls. Supplementation of the retinoate-treated rats with retinyl acetat led to a gradual increase, with the progress of time in the percentage of the spermatogonia in mitosis