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Biomedical subjects

W A Spruill

Publications and source records attributed to W A Spruill.

12 recordsLinked to original sources
PubMed1987

Multiple subdural hematomas associated with breakdancing.

A 17-year-old, previously healthy, male breakdancer presented with a three-month history of crescendo headache and newly identified papilledema. The patient was found to have four separate, unilateral extracranial collections. At surgery, three were subdural hematomas, and one was a probable arachnoid cyst containing a hematoma. These were removed, and the patient made an uneventful recovery with no neurosurgical sequelae. The possibility of serious head injury must be considered when evaluating headache in youngsters who engage in this new and apparently popular dance form.

Adolescent↗
PubMed1986

A monoclonal antibody recognizes a form of intermediate filament protein in rat Sertoli cells that is not present in seminiferous peritubular cells.

We extracted intermediate filament proteins (IFP) that were insoluble in in detergent from cultured rat Sertoli and peritubular cells after labeling with [35S] methionine and resolved them by two-dimensional polyacrylamide gel electrophoresis, autoradiography and Western blotting. We found that vimentin was the predominant IFP in both Sertoli and peritubular cells. However, while two isoelectric variants of vimentin were observed in Sertoli cells, only one was detected in peritubular cells. In addition, vimentin in Sertoli cells generated a large number of breakdown products, many differing in molecular weight and isoelectric point when compared to peritubular cells. These findings suggested that a Ca2+-activated protease, usually found in cells containing vimentin, was capable of generating proteolytic fragment patterns that were specific to cell type. Monoclonal antibodies were generated against IFP extracted from cultured Sertoli cells and their reactivity monitored by indirect immunofluorescence using Sertoli cells, peritubular cells and intact testis. One monoclonal antibody, designated IFP-SC, was an immunoglobulin (IgM) that produced a vimentin-like immunofluorescent pattern in cultured Sertoli cells. This pattern consisted of an extensive filamentous network that extended throughout the cell and surrounded the nucleus. In cultured peritubular cells, IFP-SC generated a diffuse, nonfilamentous immunoreactivity. IFP-SC reacted with components of seminiferous tubules and displayed immunoreactivity associated with Sertoli cells but not with elements of the seminiferous peritubular cell wall. Because immunofluorescent patterns were distinctly specific to cell type in cultured cells and in the intact tissue, monoclonal antibody IFP-SC is useful for the quantitative evaluation of cell cross-contamination of Sertoli and peritubular cells and, therefore, allows a precise characterization of functional events specific to cell type and monitoring of the differentiation state of cells with time in culture.

Animals↗
PubMed1985

Rat Sertoli cells acquire a beta-adrenergic response during primary culture.

Two-dimensional polyacrylamide gel electrophoresis and the radioligand (-)-[125I]iodopindolol (125I-Pin) have been used to study isoproterenol-dependent protein phosphorylation and beta-adrenergic receptor availability, respectively, in cultured Sertoli cells and freshly isolated seminiferous tubular segments of sexually immature and mature rats. Sertoli cells prepared from sexually immature rats show progressive 125I-Pin binding in primary cultures that correlates with isoproterenol-induced cell shape changes, redistribution of immunoreactive vimentin, and phosphorylation of this intermediate filament protein. The development of 125I-Pin binding to Sertoli cell lysates is blocked by cycloheximide. Seminiferous tubules do not show significant isoproterenol-dependent vimentin phosphorylation nor 125I-Pin binding. However, vimentin phosphorylation can be induced by follicle-stimulating hormone or a cyclic nucleotide analog. This study stresses the need for correlating pharmacological-induced responses observed in Sertoli cell primary cultures with those in the intact seminiferous tubule.

Animals↗
PubMed1981

Immunocytochemical localization of cyclic guanosine monophosphate-dependent protein kinase in endocrine tissues.

Antisera have been produced against purified soluble cyclic guanosine monophosphate (cGMP) dependent-protein kinase (ATP: protein phosphotransferase EC 2.7.1.37) isolated from bovine lung. No cross-reactivity was observed between the antisera and structurally related components of cAMP-dependent protein kinases (cAMP kinase), as judged by the immunodiffusion and immunoprecipitation techniques. Immunocytochemical specificity was determined by absorption of antisera with pure antigen. The distribution of cGMP kinase has been examined in several rat tissues, using an indirect immunofluorescence technique, and compared with the immunocytochemical distribution of cGMP. In skeletal muscle, cGMP kinase was localized primarily to A bands on the muscle fiber and along the Z line in I band regions. Densitometric determinations of immunoperoxidase staining indicated that absorbance over A band areas was greater than absorbance over the I band regions. In small intestine, cGMP kinase is distributed primarily along the villus brush border membrane. In testis, cGMP kinase is observed in several cell types adjacent to the seminiferous tubular wall, including Sertoli cells and spermatogonia, as well as in association with meiotic chromosomes of pachytene spermatocytes. In the cortex of the adrenal glands from dexamethasone-suppressed rats, chronic ACTH treatment induced an increase in cGMP kinase fluorescence in nuclei. In each of the tissues examined, a striking correlation was observed between the distribution of cGMP kinase and cGMP, supporting the hypothesis that cGMP-mediated actions occur via cGMP kinases.

Adrenal Glands↗
PubMed1980

Localization of androgen-binding protein in proliferating Sertoli cells in culture.

The peroxidase and immunofluorescent localization patterns of androgen-binding protein (ABP), a biological marker of Sertoli cell function, have been examined in cultured Sertoli cells isolated from 20- to 22-day-old rats. ABP immunoreactivity in the form of cytoplasmic granules of variable diameter was observed in Sertoli cells with characteristic lipid droplets and a colony-forming, epithelial-like growth pattern. Incubation of cultures with [3H]thymidine demonstrated that Sertoli cells continue to produce ABP while retaining their capability for synthesizing DNA and undergoing mitosis. A variable number of cultured Sertoli cells became morphologically transformed after exposure to follitropin (follicle-stimulating hormone) and pharmacological agents acting on cyclic nucleotide metabolism. The induced change in Sertoli cell shape coincided with a disappearance of ABP-containing granules from the cytoplasm. These observations demonstrate that localization of ABP by immunological techniques is a valuable tool for the characterization of structural and functional properties of Sertoli cell in culture.

1-Methyl-3-isobutylxanthine↗
PubMed1979

Characterization of rat testicular guanylate cyclase during development.

The biochemical characteristics of rat testicular guanylate cyclase were investigated and the activity and subcellular distribution of the enzyme was determined during testicular development. Examination of the effects of metal ions, nucleotides, detergents and other in vitro activators on the activity of guanylate cyclase revealed that the testicular enzyme is similar in most respects to guanylate cyclase isolated from other mammalian tissues. Changes in the total activity of guanylate cyclase during testicular development paralleled changes in the tissue concentration of cyclic GMP; i.e. guanylate cyclase activity and tissue cyclic GMP were highest during the early stages of development. Subcellular fractionation revealed that the activity of the soluble form of guanylate cyclase was best correlated with tissue cyclic GMP. Biochemical analysis of the soluble enzyme prepared from testes of neonatal and adult rats did not reveal any significant differences in the characteristics of the enzyme during ontogeny with the exception of a 2.5 fold increase in V noted in the neonatal testis. The results of this study are consistent with a molecular mechanism that allows independent regulation of the different forms of guanylate cyclase.

Adenosine Triphosphate↗
PubMed1978

Association of cyclic GMP with gene expression of polytene chromosomes of Drosophila melanogaster.

The distribution of cyclic nucleotides on polytene chromosomes isolated from Drosophilia melanogaster salivary glands was examined by using an indirect immunofluorescent technique. With a fixative that minimized the loss of chromosomal proteins, cyclic GMP, but not cyclic AMP, was observed distributed along the chromosomes. The subchromosomal distribution of cyclic GMP correlated with genetically active sites on the chromosomes. After heat-shock treatments, the intensity of cyclic GMP fluorescence was markedly enhanced at specific loci on the chromosomes, with locus 93D as the most intensely fluorescent. Autoradiographic analysis with [3H]uridine revealed that 93D was the most transcriptionally active locus within a particular nucleus. These observations suggest that cyclic GMP may participate in processes associated with transcription on polytene chromosomes. The involvement of cyclic GMP in nuclear events associated with gene expression is discussed.

Animals↗
PubMed1978

Tissue guanosine-3',5'-cyclic monophosphate levels and soluble guanylate cyclase activity: a positive correlation during unilateral cryptorchidism in the rat testis.

The relationship between the subcellular distribution of guanylate cyclase and tissue guanosine-3',5'-cyclic monophosphate (cGMP) levels was investigated in rat testes after surgically induced unilateral cryptorchidism. Placement of one of a testis pair in the abdominal cavity results in loss of testicular weight and function in the abdominal testis whereas the remaining scrotal testis appears to be functionally normal. Within 5 days after surgery, tissue cGMP levels were increased by twofold in the abdominal testis. A fourfold elevation was noted from 10 to 30 days after surgery. Whereas the homogenate guanylate cyclase activity was only slightly elevated 10 and 20 days postoperatively, a 200% increase in the soluble guanylate cyclase activity was seen at 5 days. Between 10 and 30 days, the rise in activity was >250% (P < 0.01). An increase in soluble guanylate cyclase activity was noted when the data were expressed as per milligram protein, per milligram DNA or per whole testis. Conversely, particulate guanylate cyclase activity was reduced by 40% in the cryptorchid testis. Kinetic analysis of the soluble enzyme prepared from abdominal and scrotal testes yielded linear Line-weaver-Burke plots for both enzyme preparations with an identical K(m) for guanosine triphosphate, but a three-fold higher maximal velocity for the abdominal enzyme. When the soluble guanylate cyclases from both testes were mixed and assayed together, the activities were additive rather than exhibiting synergism or inhibition. These experiments indicate that the altered V(max) is not due to a transferable activator or inhibitor.An immunocytochemical technique was used to assess the cell type in which the alterations in cGMP metabolism occurred. Comparison of the scrotal and abdominal testes revealed that the abdominal testis exhibited enhanced cGMP immunofluorescence within the cells lining the inner aspect of the seminiferous tubule as well as tubular elements and interstitial cells. Thus, it is inferred that the correlated changes in soluble guanylate cyclase activity and cGMP levels occur in several of the cell types that remain viable within the cryptorchid testis.

Animals↗
PubMed1975

Central monaminergic neuronal effects on minimum alveolar concentrations (MAC) of halothane and cyclopropane in rats.

The effect of interference with central catecholamine- or serotonin-containing neurons on the response of rats to inhalation anesthetics were explored. Interference with catecholaminergic function by inhibition of amine synthesis with alpha-methyltyrosine alone or combined with destruction of these neurons by 6-hydroxydopamine reduced brain concentrations of norepinephrine and dopamine without altering serotonin concentrations. These alterations decreased the minimum alveolar concentration (MAC) of halothane when tail-clamping was used as the test stimulus. Similar small reductions of halothane MAC were produced in rats given 5,6-dihydroxytryptamine and p-chlorophenylalanine, which decreased brain serotonin without altering noreopinephrine or doapamine concentrations. When catecholaminergic or serotoninergic neuronal function was similarly disrupted in rats later exposed to cyclopropane, no alternation in MAC was observed. It is suggested that disruption of central amine-containing neurons may lower the MAC's of depressant anesthetics only, and not excitatory anesthetics.

Amines↗