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J C Hutson

Publications and source records attributed to J C Hutson.

48 records · Page 3Linked to original sources
PubMed1978

Quantitation of mitochondrial DNA and protein in the liver of Fischer 344 rats during aging.

Mitochondria from liver whole homogenates of Fischer 344 rats, 3,6, 12 and 24 mo of age were separated by reorienting rate-zonal centrifugation on sucrose gradients. Employing this method, mitochondria can be harvested nearly quantitatively and subjected to a number of biochemical analyses. Separation and recovery of the mitochondria from young and old rats was monitored by assaying each fraction from the gradient for cytochrome oxidase and lipoamide dehydrogenase, two mitochondrial specific enzymes. In addition, several regions of the gradient were studied by transmission electron microscopy. In this study, mitochondrial DNA and protein were quantitated from the livers of the animals at each age group. It was demonstrated that between the ages of 12 and 24 mo these macromolecules decreased significantly. These data would seem to indicate that the number of mitochondria is decreased in this tissue in aged animals.

Aging↗
PubMed1977

Polyglactin 910 suture in urinary tract.

Cystotomies in guinea pigs and ureteral anastomoses in dogs were sutured with polyglactin 910. Silk and chromic catgut were used as control sutures in the bladders and chromic catgut in the ureters. Three months postoperatively in bladders sutured with polyglactin 910 small epithelial cysts were noted, which increased in size with time. In ureters sutured with polyglactin 910 cystic diverticula were observed eight months postoperatively. Because of the difference of tissue reaction to polyglactin 910 compared with catgut, further long-term studies are urged in different species of animals, prior to the clinical use of polyglactin 910 in the urinary tract.

Animals↗
PubMed1977

Immunocytochemical localization of a folicle stimulating hormone-like molecule in the testis.

A follicle-stimulating hormone (FSH)-like molecule was localized in normal adult rat testes as well as testosterone-treated hypophysectomized rat tests with an unlabeled antibody (anti-FSH), peroxidase-antiperoxidase complex technique. Anti-FSH bound specifically to ultrathin sections of acrosomes of spermatids and intranuclear bodies of early spermatids. Quantitation of staining intensity demonstrated that FSH, used as an absorbing antigen, would significantly reduce this binding. There was less anti-FSH binding to the acrosomes of spermatozoa in the body and tail of the epididymis as compared to the less mature germ cells located in the testis and head of the epididymis. The acrosomal and nuclear staining of spermatids taken from hypophysectomized animals was similar to staining observed in sham injected animals. Taken together, these results suggest that there is a molecule within the acrosome that is immunologically similar to FSH. Most importantly, these results emphasize the importance of conducting physiologic experiments in conjunction with immunocytochemical studies.

Animals↗
PubMed1976

Changes in testis of guinea pig after vasectomy.

Thirty adult guinea pigs were bilaterally vasectomized and subsequently sacrificed at one, three, and six months after operation. Cell counts were performed on five seminiferous tubules from each animal to identify and quantitate changes in spermatogenesis. Forty-three per cent of the animals had alterations in spermatogenesis that were characterized by generalized hypospermatogenesis and presence of multinucleated spermatids. There was a high incidence (93 per cent) of sperm-agglutinating antibodies in the vasectomized group. Sperm antibodies were not detected in the normal and sham-operated animals. Mean testicular weights and seminiferous tubule diameters were significantly reduced in the hypospermatogenic animals. The intersitial tissue of the vasectomized and sham-operated animals was morphologically indistinguishable from that of unoperated animals.

Animals↗
PubMedDate not supplied

Leydig cells do not have Fc receptors.

It has been reported that Leydig cells have Fc receptors, which traditionally have been considered markers specific for macrophages and polymorphonuclear leukocytes. The purpose of this investigation was to study further this phenomenon and also to determine if Leydig cells and macrophages could be separated from each other either by density gradient centrifugation using Percoll or by differential detachment with trypsin treatment of cultures of crude interstitial preparations. Interstitial cells were obtained by collagenase digestion of rat testis and established in culture. These cultures were reacted for 3 beta-steroid dehydrogenase and Fc receptor and viewed with phase contrast microscopy. No individual cells were positive for both steroid dehydrogenase activity and Fc receptors. The order in which the cells were stained for these two markers did not influence the results. Trypsin treatment of these crude interstitial cultures removed over 90% of the Leydig cells and approximately 20% of the macrophages. Macrophages were located in the same portion of Percoll gradients as the less dense (Population I) Leydig cells, while Leydig cells found in the dense area of the gradient (Population II) were not contaminated with macrophages. These studies indicate that Leydig cells do not have Fc receptors and that a subpopulation of Leydig cells can be isolated free of macrophages using density gradient centrifugation.

Animals↗
PubMedDate not supplied

Salicylate or bismuth salts enhance opsonophagocytosis of Klebsiella pneumoniae.

After treatment of encapsulated Klebsiella pneumoniae with salicylate or bismuth compounds, phagocytic uptake by human peripheral white blood cells or rat alveolar macrophages was assessed. Without salicylate pretreatment of bacteria, a 30-60% net increase in viable bacteria resulted in phagocytic assays after a 1 hour incubation. With salicylate pretreatment, dose-related decreases in bacterial counts were seen, achieving a maximal reduction of 60% with 240 microM salicylate pretreatment. Bacterial variants producing less capsule were more serum sensitive and more readily phagocytosed. Micrographs of Giemsa-stained cells revealed phagocytic uptake of multiple bacteria after salicylate pretreatment, but virtually no uptake of untreated bacteria. Opsonization with polyclonal antiserum decreased bacterial cell counts by 20% without and by 90% with salicylate pretreatment of bacteria. Pretreatment of bacteria with bismuth salts also enhanced opsonophagocytosis of encapsulated bacteria. Thus, agents known to reduce capsule expression in K. pneumoniae also enhance phagocytic uptake of bacteria.

Adult↗
PubMedDate not supplied

Ethane dimethane sulfonate and NNN'N'-tetrakis-(2-pyridylmethyl)ethylenediamine inhibit steroidogenic acute regulatory (StAR) protein expression in MA-10 Leydig cells and rat Sertoli cells.

Apoptosis inhibits steroid biosynthesis, but it is not clear how the Steroidogenic Acute Regulatory (StAR) protein, is affected. To characterize StAR expression during apoptosis, mouse MA-10 Leydig tumor cells were treated with ethane dimethane sulfonate (EDS), an inducer of apoptosis, and the metal ion chelator NNN'N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN), an inducer of cell death. Both chemicals induced cell death and similarly inhibited dbcAMP-stimulated steroidogenesis and accumulation of the 30 kDa form of StAR. Utilizing the dye JC-1, it was found that TPEN and EDS also impaired the mitochondrial electrochemical potential (delta psi). In Sertoli cells, which also express StAR, EDS induced cell death and attenuated StAR expression. We conclude 1) steroidogenesis and accumulation of mature StAR protein are inhibited as a consequence of the induction of apoptosis; 2) reduced levels of StAR may be partially attributed to inhibition of import because of the loss of delta psi; 3) loss of steroidogenesis is probably due to loss of StAR synthesis and disruption of delta psi.

Animals↗
PubMedDate not supplied

Comparison of cellular and secreted proteins of macrophages from the testis and peritoneum on two-dimensional polyacrylamide gels: evidence of tissue specific function.

It has been shown that the testis contains a population of cells with many characteristics typical of macrophages of other tissues. However, these macrophages are unique in that they secrete a product(s) that is responsible for stimulating testosterone secretion by Leydig cells while peritoneal macrophages have no similar effect. The purpose of the present study was to compare the pattern of cellular and secreted proteins of rat testicular macrophages to those of peritoneal macrophages using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Cellular and secreted proteins of cultured macrophages from the testis and peritoneum were labeled with 35S-methionine and 35S-cystine and then analyzed by 2D-PAGE using a computer-assisted image analysis system. It was found that the patterns of both cellular and secreted proteins of testicular macrophages were vastly different than those of peritoneal macrophages. One striking difference was the presence of a family of proteins in the 47 kd range, with a range of pI from 5.7-6.3 that represented approximately 57% of the total protein secreted by testicular macrophages. Proteins of similar molecular weight and pI represented only approximately 15% of the total peritoneal macrophage secreted proteins. Many other differences were observed in less abundant cellular and secreted proteins. These studies strongly support the concept that macrophages are functionally heterogeneous and secrete a group of proteins characteristic to the histological location of these cells.

Animals↗
PubMedDate not supplied

Purification and characterization of a lipophilic factor from testicular macrophages that stimulates testosterone production by Leydig cells.

Testicular macrophages have been shown to secrete a factor that stimulates testosterone production by Leydig cells. The purpose of this investigation was to purify and characterize this factor. Medium was collected from 24- to 48-hour cultures of testicular macrophages isolated from adult rats. This medium induced a sevenfold increase in testosterone production by cultured Leydig cells. When the medium was extracted with ether, all biological activity was found in the organic phase, indicating that the factor was lipophilic. The ether extract was then fractionated on a C18 reversed-phase high-performance liquid chromatography (HPLC) column, using a gradient of acidified methanol as the mobile phase. Leydig cell-stimulating activity eluted at approximately 11 minutes. Standards of testosterone, dihydroepiandrosterone (DHEA), pregnenolone, progesterone, dihydrotestosterone (DHT), and prostaglandin E2 (PGE2) all had elution times of between 5 and 6 minutes, under identical column conditions. The biological activity of the HPLC-purified fraction was partly resistant to boiling but was completely abolished by Dextran-coated charcoal treatment. Biological activity of testicular macrophage-conditioned medium was not abolished following chymotrypsin treatment, indicating that this molecule was not a hydrophilic peptide. It was found that the factor obtained by reversed-phase HPLC could be further purified by normal-phase HPLC. The results of this investigation demonstrate that the testicular macrophage-derived factor that stimulates testosterone production by Leydig cells can be purified by organic extraction and HPLC, and that it is a highly potent chymotrypsin-resistant heat-stable lipophilic factor.

Animals↗
PubMedDate not supplied

FSH does not directly influence testicular macrophages.

We have previously demonstrated that conditioned medium from testicular macrophages stimulates testosterone production by Leydig cells. It was also reported that conditioned medium from macrophages treated with follicle-stimulating hormone (FSH) had an even greater amount of Leydig cell-stimulating activity than medium from untreated macrophages, indicating that this factor is under the regulation of FSH. However, most other laboratories have been unable to reproduce this effect of FSH. We have recently purified and partially characterized the stimulatory factor from macrophage-conditioned medium that stimulates Leydig cells. The purpose of the present investigation was to reinvestigate the effect of FSH by determining whether it regulates the production of this purified factor and by determining whether macrophages have mRNA for the FSH receptor. Testicular macrophages were isolated from adult rats and incubated 24 hours with human recombinant FSH (20 units/ml), ovine FSH (200 ng/ml), fetal bovine serum (2%), or dibutyryl cyclic adenosine monophosphate (1 mM). The macrophage-derived factor (MDF) was then purified from conditioned medium of the various treatment groups and added to Leydig cells. The concentration of testosterone in the Leydig cell medium was then measured after 16 hours. It was found that serum significantly stimulated production of the MDF. However, FSH had no effect on production of the MDF in the presence or absence of serum. Dibutyryl cyclic adenosine monophosphate exerted a slight inhibitory effect on production of the macrophage-derived factor. Most importantly, testicular macrophages did not express detectable levels of FSH receptor mRNA, either in vivo or in vitro, when evaluated using either in situ hybridization or northern analysis, under identical conditions that clearly demonstrated FSH receptor mRNA in Sertoli cells. We conclude that testicular macrophages are not a direct target for FSH.

Animals↗