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D F Cameron

Publications and source records attributed to D F Cameron.

62 records · Page 4Linked to original sources
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Selected enzyme histochemistry of Sertoli cells. 1. Immature rat Sertoli cells in vitro.

Sertoli cells were collected from the testes of 21 day old, sexually immature Wistar rats. The cells were then incubated for 10 or 14 days in culture medium with or without the addition of FSH. This time period corresponds to the time period in vivo when rat Sertoli cells undergo active differentiation with concomitant histochemical and morphological changes. Cells cultured 10 and 14 days after initial plating were processed for the histochemical detection of three esterases and four dehydrogenases by observing relative staining intensities of azo dye precipitation and formazan reaction product, respectively. Appropriate controls were established. The presence of FSH mildly increased the staining activity of LDH, SDH and G-6-PDH in both 10 and 14 day cultured cells. However, SDH staining intensity/cell did not increase to surpass LDH staining intensity/cell as it does in vivo during this period of time. Addition of FSH also slightly increased staining of non-specific esterase. Type B esterase and 3 beta-ol DH activity was not evident in 10 and 14 day cultured cells, even in the presence of FSH. Our results indicate that, based on histochemical parameters, immature Sertoli cells do not mature in culture commensurate with the cell in vivo.

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Selected enzyme histochemistry of Sertoli cells. 2. Adult rat Sertoli cells in co-culture with peritubular fibroblasts.

Sertoli cells and peritubular fibroblasts were collected from sexually mature Wistar rats and incubated by themselves (ASC) or in co-culture (AS/PC) for ten days with or without follicle stimulating hormone (FSH). Freshly collected cells and those of the ASC and AS/PC cultures were processed for histochemical detection of three esterases and four dehydrogenases. The relative staining intensities of azo dye and formazan reaction products were recorded for the cell cultures, co-cultures and appropriate controls. Freshly collected Sertoli cells stained heavily for lactic dehydrogenase (LDH), succinic dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (G-6-PDH), non-specific esterase (Est.) and 3 beta-hydroxysteroid dehydrogenase (3 beta-OLDH). For Sertoli cells alone in culture (ASC) there was a marked decline of enzyme reaction product deposition/cell for LDH and Est. and absence of cellular staining for SDH, G-G-PDH, B-Est. and 3 beta-OLDH. The addition of FSH did not change this histochemical staining pattern for the adult cells in vitro. The presence of peritubular cells in adult Sertoli cell cultures (AS/PC) resulted in the maintenance of metabolic enzyme staining (i.e., LDH, SDH, G-6-PDH and Est.) in Sertoli cells, minimal staining for B-Est., but absence of detectable enzyme reaction product for 3 beta-OLDH. Sertoli cells co-cultured with other fibroblasts or in medium pre-conditioned with peritubular cells but not containing them stained minimally for LDH and Est. and did not generate reaction product for any of the other enzymes. The addition of FSH to the AS/PT co-culture as in the ASC cultures did not affect the enzyme histochemical staining profile of Sertoli cells.(ABSTRACT TRUNCATED AT 250 WORDS)

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Sertoli cell-enriched fractions in successful islet cell transplantation.

Prolonged survival of Islet- allo- and xenografts can be induced following implantation of the islets into the abdominal testis of diabetic rats. We previously showed that a factor released by Sertoli cells appears to be responsible for the protection of the intratesticular islet allo- and xenografts against rejection. The aim of this study was to examine whether an immunologically privileged site can be established in an organ site in vivo, other than the testis, such as the renal, subcapsular space, to make feasible the grafting of female recipients as well. A total of 36 male and 21 female, diabetic, PVG rats were divided into six different treatment groups: 1) Six male rats were grafted with islets from Sprague-Dawley (S-D) donor rats only. 2) Ten male rats were grafted with islets from (S-D) donors and were then given a short course of cyclosporine (CsA) posttransplantation. 3) Ten male rats were grafted with islets from (S-D) donors and with Sertoli cell-enriched fractions (SEF) from PVG donors but without CsA. 4) Ten male rats were grafted with a combination of islets from (S-D) and SEF from (PVG), donors, respectively, and CsA. 5) Ten female rats were given an identical combination of cells and CsA as depicted for group 5. 6) Ten female rats were grafted with a combination of islets and SEF, both cell types from S-D donors, and CsA. The results showed that 70% to 100% of the grafted rats in groups 1, 2, and 3 remained hyperglycemic.(ABSTRACT TRUNCATED AT 250 WORDS)

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Post-thaw viability and functionality of cryopreserved rat fetal brain cells cocultured with Sertoli cells.

Testis-derived Sertoli cells have been used to create an immune "privileged" site outside of the testis to facilitate cell transplantation protocols for diabetes and neurodegenerative diseases. In addition to secreting immunoprotective factors, Sertoli cells also secrete growth and trophic factors that appear to enhance the posttransplantation viability of isolated cells and, likewise, the postthaw viability of isolated, cryopreserved cells. It would be beneficial if Sertoli cells could be cryopreserved with the transplantable cell type without deleterious effects on the cells. This report describes a protocol for the cocryopreservation of rat Sertoli cells with rat ventral mesencephalic neurons, neurons from the lateral and medial ganglionic eminences and the hNT neuron cell line, and reports on the effects of Sertoli cells on the the postthaw viability of these neurons. Results of trypan blue exclusion analysis indicated that the presence of Sertoli cells did not deleteriously effect cryopreserved neurons and may improve their postthaw recoverability and viability in general. Specifically, results of the tyrosine hydroxylase immunostaining showed that Sertoli cells significantly enhance the postthaw viability of ventral mesencephalic dopaminergic cells in vitro.

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Trophic effect of porcine Sertoli cells on rat and human ventral mesencephalic cells and hNT neurons in vitro.

The poor survival of embryonic dopaminergic (DA) neurons transplanted into patients with Parkinson's disease (PD) has encouraged researchers to search for new methods to affect the short- as well as long-term survival of these neurons after transplantation. In several previous rodent studies Sertoli cells increased survival of islet cells and chromaffin cells when cotransplanted in vivo. The aims of this study were to investigate whether porcine Sertoli cells had a positive effect on the survival and maturation of rat and human DA neurons, and whether the Sertoli cells had an effect on differentiation of neurons derived from a human teratocarcinoma cell line (hNT neurons). A significant increase of tyrosine hydroxylase (TH)-positive neurons of both rat and human ventral mesencephalic tissue was found when cocultured with Sertoli cells. Furthermore, there was a significantly increased soma size and neurite outgrowth of neurons in the coculture treated group. The Sertoli cell and hNT coculture also revealed an increased number of TH-positive cells. These results demonstrate that the wide variety of proteins and factors secreted by porcine Sertoli cells benefit the survival and maturation of embryonic DA neurons and suggest that cotransplantation of Sertoli cells and embryonic DA neurons may be useful for a cell transplantation therapy in PD.

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Temporal relation between leptin and various indices of sexual maturation in the male rat.

Recent studies in humans and rhesus monkeys have suggested the possibility that the adipose tissue hormone leptin has a stimulatory and/or permissive effect on the onset of puberty in the male. We evaluated this hypothesis by measuring leptin in groups of male rats between the ages of 26 days and 96 days. A statistically significant positive correlation was present between serum leptin and age, body weight, prostate, seminal vesicle, and testes weight (both absolute and as a function of body weight). A statistically significant negative correlation was present between leptin and serum FSH and alpha-inhibin. There was not a statistically significant correlation between leptin and testosterone or LH. There was a statistically significant increase in the serum leptin concentrations at day 47. This rise was coincident with the peripubertal growth spurt in the secondary sexual organs and the peripubertal testosterone rise but occurred after the prepubertal rise in testicular weight, the appearance of elongating spermatids in the testes, and the start of the decline in FSH. In animals in which the peripubertal testosterone rise was delayed by the administration of EDS, serum leptin showed statistically significant differences from control. These data do not support the hypothesis that leptin provides a trigger for the onset of puberty in the male rat. They do suggest that leptin may be involved in the secondary sexual organ growth spurt and are consistent with the hypothesis that testosterone stimulates leptin synthesis during puberty.

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Development of Sertoli cell binding competency in the peripubertal rat.

The peripheral distribution of Sertoli cell F-actin, a cytoskeletal protein found in Sertoli cell ectoplasmic specializations, is associated with enhanced spermatid binding to the Sertoli cell and, as such, serves as a functional marker for its acquisition of binding competency. Previous studies suggest that the peripheral distribution of actin is dependent on follicle-stimulating hormone (FSH). To investigate the developmental pattern of Sertoli cell actin distribution in relation to peripubertal FSH and testosterone levels, we examined epithelial sheets from 2-8 week-old-rats. Tissues were processed for light microscopy and for the visualization of rhodamine-labeled F-actin. At 2 weeks, actin staining was diffuse throughout most of the Sertoli cells and was similar to that observed in binding-incompetent Sertoli cells. By 4 weeks, actin distribution was peripheral, acquiring the same staining pattern as observed in binding-competent Sertoli cells. Serum levels of FSH peaked at 4 weeks and declined to adult levels thereafter. Testosterone levels did not increase significantly until 6 weeks. Results show that Sertoli cell actin undergoes peripheral reorganization concurrent with the peripubertal peak of FSH but prior to the peripubertal rise of testosterone. The study demonstrates a temporal correlation between the peripubertal FSH rise and the actin redistribution in Sertoli cells that is consistent with an induction of this redistribution by FSH. These results suggest that FSH induces binding competency in Sertoli cells.

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