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E S Hall

Publications and source records attributed to E S Hall.

At least 19 recordsLinked to original sources
PubMed1996

Kinesin localizes to the trans-Golgi network regardless of microtubule organization.

Knowledge of the mechanisms of intracellular membrane trafficking is critical for understanding cell function. Here, the microtubule motor kinesin is localized to the Sertoli cell trans-Golgi network with the SUK4 kinesin monoclonal antibody. Using immunoelectron and immunofluorescence microscopy, kinesin was shown to localize to the trans-Golgi network in primary Sertoli cell cultures. Kinesin immunostaining was not observed in brefeldin A-induced trans-Golgi network-derived membrane tubules and remained associated with trans-Golgi network remnants. Despite dramatic differences in microtubule organization between Sertoli cells in vivo and in vitro, kinesin immunostaining was consistently associated with the trans-Golgi network. In cryosections of control testis and testis treated with colchicine to disrupt microtubules, kinesin immunostaining was juxtaposed with immunostaining for a Golgi cisternal protein; however, brefeldin A exposure partitioned the kinesin immunostaining from the Golgi cisternal protein, indicating that kinesin was associated with the trans-Golgi network of Sertoli cells in vivo. These results are discussed in relation to known Golgi-associated microtubule-dependent transport events in other cell types and suggest that kinesin functions locally at the Sertoli cell trans-Golgi network.

Animals↗
PubMed1995

Distribution of Sertoli cell microtubules, microtubule-dependent motors, and the Golgi apparatus before and after tight junction formation in developing rat testis.

Sertoli cells are polarized epithelial cells of the seminiferous epithelium which provide structural and physiological support for differentiating germ cells. They establish different basal and adluminal environments for the selective nurturing of pre- and post-meiotic germ cells within the seminiferous epithelium, segregated by the Sertoli-Sertoli cell tight junctional complex, the blood-testis barrier. Tight junction formation between epithelial cells in vitro is a critical polarizing event associated with changes in polarized targeting of membrane-specific proteins and reorganization of microtubules, centrioles, and the Golgi apparatus. To investigate whether tight junction formation is associated with organelle reorganization in Sertoli cells in vivo, we have characterized distribution patterns of Sertoli cell microtubules, the mechanoenzymes kinesin and cytoplasmic dynein, and the Golgi apparatus during tight junction formation in developing rat testis. Immunocytochemistry on samples taken at 5, 10, 15, 20, and 25 days of age was used to examine the distribution of these proteins during the extensive cellular reorganization that culminates in the formation of the blood-testis barrier at 19 days of age. Our data show that the distribution patterns reflect the extensive intercellular repositioning of tubule cells in developing seminiferous tubules, but that changes in intracellular organization are not temporally associated with formation of the blood-testis barrier.

Age Factors↗
PubMed1995

2,5-Hexanedione exposure alters microtubule motor distribution in adult rat testis.

2,5-Hexanedione (2,5-HD) exposure in rats causes a progressive Sertoli cell injury culminating in testicular atrophy. Morphological injury is preceded by alterations in the assembly characteristics of tubulin isolated from exposed rat testes. This is followed by decreased seminiferous tubule fluid (STF) secretion by Sertoli cells and an increase in the number and size of Sertoli cell vacuoles. The possible involvement of microtubules and microtubule motor-dependent transport processes in STF secretion by Sertoli cells prompted us to examine the immunodistribution of the microtubule motors cytoplasmic dynein and kinesin during and after 2,5-HD exposure in rats. Three weeks following the commencement of exposure (1% 2,5-HD in the drinking water), the intensity of apical Sertoli cell cytoplasmic dynein immunofluorescence declined. This staining deficit became statistically significant by 4 weeks of exposure. Accompanying this change, there was progressive disruption of the immunodistribution of cisternal Golgi elements and associated kinesin immunoreactivity. The decrease in apical Sertoli cell cytoplasmic dynein immunofluorescence and disruption of Golgi and kinesin immunoreactivity suggest that 2,5-HD-induced alterations in Sertoli cell-mediated transport and secretory events could involve deficits in microtubule-dependent motor function.

Animals↗
PubMed1995

Dialysis survival in a large inner-city facility: a comparison to national rates.

Impoverished patients may represent a high-risk population with poor survival. With 1993 U.S. Renal Data System survival tables (to adjust the risk of death for differences in age, race, and ESRD diagnosis), the mortality rates of patients over 3 yr in a large inner-city dialysis facility using high-flux technique were compared with national averages. At least 93.7% of patients were African-American, 50% had incomes below $7,000 per year, and employment was 5% or less. Observed and expected deaths (the latter derived from the U.S. Renal Data System tables) were used to calculate a standardized mortality ratio (observed deaths/expected deaths); the U.S. average is 1.0. The standardized mortality ratio at this facility for each year was < 0.600 and was significantly lower than the U.S. average in 1991, in 1992 (P < 0.05), and for all 3 yr (P < .001). Over all 3 yr, it was lower for females (0.540, P < 0.05), males (0.620, P < 0.05), patients with diabetes (0.593, P < 0.05), and glomerulonephritis (0.318, P < 0.05). For the 3 yr, a Cox regression analysis revealed independent associations between mortality and age (P = 0.004), serum albumin (P = 0.02), Kt/V (P = 0.02), and dialysis for more than 2 yr (P = 0.01). Patients with economic hardship can attain survival significantly better than the national average with the provision of adequate dialysis, nutrition, and support services.

Adult↗
PubMed1994

Cellular localization of tissue factor and prothrombin in the estrogen-treated immature rat uterus.

The immediate early responses of the immature rat uterus to estradiol include increases in tissue factor and prothrombin, two proteins of the coagulation cascade. Both attain maximum activity within 3 h after the administration of estradiol and return to control levels after 12-18 h. The presence of the two proteins allows the generation of thrombin (a known growth factor for fibroblasts) in the uterus at the time when uterine growth begins. To further our hypothesis that thrombin is an estrogen-regulated uterine growth factor, we used immunohistochemistry, Western blotting, and coagulation assays to localize the cell types in which these proteins are increased by estradiol. Tissue factor is increased in both the stromal and the epithelial cells. Increased prothrombin is localized primarily along the basement membrane that separates the epithelial and stromal layers and also at the luminal surface of the epithelium.

Amino Acid Sequence↗
PubMed1993

Protein binding and hepatobiliary distribution of valproic acid and valproate glucuronide in rats.

The protein binding and hepatobiliary distribution of valproic acid (VPA) and its glucuronide conjugate (V-G) were examined in rats with a combination of in vitro and ex vivo protocols. VPA was moderately bound to proteins in both serum and hepatic cytosol, and the degree of binding was lower ex vivo than in vitro. V-G, which was more highly bound than VPA ex vivo in serum, may have displaced the parent drug from its binding sites when VPA was administered in vivo. Examination of ex vivo hepatic subcellular distribution revealed that VPA localization tended to be high in cytosol and low in the microsomal fraction; V-G appeared to be distributed evenly throughout the cell although V-G concentrations within the liver were very low. The steady-state elimination rate of VPA did not increase proportionately with increasing steady-state concentrations of unbound VPA in serum, consistent with saturable systemic elimination of the drug. In contrast, steady-state VPA elimination was related linearly to unbound cytosolic VPA concentrations. Moreover, a nonlinear relationship between the unbound concentrations of VPA in hepatic cytosol and serum was observed, consistent with saturable distribution of the unbound drug between the two compartments in vivo. These observations suggest that the nonlinear elimination of VPA in rats may be due to concentration-dependent penetration of the drug into the liver as opposed to saturable biotransformation.

Animals↗
PubMed1993

The cytotoxicity of N-substituted indazolones in murine and human tumor cells.

N-Substituted indazolones are effective cytotoxic agents, causing cell death in a number of tissue culture lines, e.g. L1210, Tmolt3, colon adenocarcinoma and HeLa-S3. Selected agents were also active against the growth of KB, bronchogenic lung, osteosarcoma and glioma. The mode of action of the derivatives involves inhibition of de novo purine synthesis of L1210 cells, which reduces DNA and RNA syntheses. Agents lowered d(NTP) pools, further reducing DNA synthesis. DNA strand scission was evident after incubation with N-substituted indazolones for 24 h at 100 microM, lowering DNA synthesis and causing cell death.

Animals↗
PubMed1992

Sertoli cells isolated from adult 2,5-hexanedione-exposed rats exhibit atypical morphology and actin distribution.

Sertoli cells were isolated from 2,5-hexanedione (2,5-HD)-exposed, cryptorchid and 21-day-old rats in order to examine alterations in in vitro Sertoli cell transferrin secretion, germ cell adhesion, in vitro morphology, and cytoskeletal organization which might be involved in the irreversibility of 2,5-HD-induced testicular injury. Sertoli cells isolated from 21-day-old, cryptorchid and 2,5-HD-exposed rats exhibited similar transferrin secretion as measured using an enzyme-linked immunosorbent assay. Germ-cell adhesion was measured using [3H]leucine-labeled immature rat germ cells and revealed similar levels of germ-cell binding in Sertoli cell cultures isolated from the three groups of rats. Differential interference contrast microscopy demonstrated that Sertoli cells isolated from 2,5-HD-exposed rats possessed an atypical spindle shape and long cytoplasmic processes. The immunofluorescent distribution of tubulin and vimentin corresponded with the morphological appearance of the cells with well-defined microtubule and intermediate filament networks which, in the cells isolated from 2,5-HD-exposed rats, extended into the cytoplasmic processes. Rhodamine-conjugated phalloidin-labeled actin stress fibers were decreased in density within the 2,5-HD-exposed rat Sertoli cells. The altered morphology and distribution of actin filaments within Sertoli cells isolated from adult 2,5-HD-exposed rats may reflect an underlying insult which is involved in the irreversible nature of 2,5-HD intoxication.

Actins↗
PubMed1992

Tau, the neuronal heat-stable microtubule-associated protein, is also present in the cross-linked microtubule network of the testicular spermatid manchette.

The seminiferous tubule of the testis contains a rich variety of microtubule networks and of microtubule-associated proteins (MAPs). Tau is a heat-stable MAP previously believed to be limited in its expression in mammals to the nervous system. We have identified tau in rat and bovine testis, a unique non-neuronal location, using biochemical, molecular, and immunologic approaches. SDS-PAGE of ammonium sulfate-fractionated, testis heat-stable MAPs resulted in an enrichment of bands that comigrated with rat brain tau. Only the 35-45% precipitated ammonium sulfate fraction induced microtubule assembly. Immunoblotting with monoclonal anti-tau antibodies demonstrated tau immunoreactivity in these testis MAP preparations. Northern analysis of total rat testis RNA demonstrated a 1.7-kb band that hybridized with a 51-nucleotide oligomer complementary to a conserved portion of the tau transcript. This 51-mer identified a similar 1.7-kb minor band and an additional 6-kb major band in Northern analysis of total rat brain RNA. Finally, in the bull testis, immunohistochemistry localized tau to the spermatid manchette, a transient, cross-linked microtubule network of unknown function. As spermatid elongation begins, the manchette forms a sheath around the posterior aspect of the nucleus, but, by the completion of nuclear condensation, the manchette is largely disassembled. Tau most likely plays a structural role in the manchette; however, tau immunoreactivity also was observed in late stage I spermatids prior to manchette formation, suggesting that tau may serve a function in manchette assembly.

Animals↗
PubMed1992

Distribution of the microtubule-dependent motors cytoplasmic dynein and kinesin in rat testis.

To examine the possible role of microtubule-based transport in testicular function, we used immunofluorescent techniques to study the presence and localization of the microtubule mechanoenzymes cytoplasmic dynein (a slow-growing end-directed motor) and kinesin (a fast-growing end-directed motor) within rat testis. Cytoplasmic dynein immunofluorescence was observed in Sertoli cells during all stages of spermatogenesis, with a peak in apical cytoplasm during stages IX-XIV. Cytoplasmic dynein immunofluorescence was also localized within Sertoli cells to steps 9-14 (stages IX-XIV) germ cell-associated ectoplasmic specializations. In germ cells, cytoplasmic dynein immunofluorescence was observed in manchettes of steps 15-17 (stages I-IV) spermatids, and small, hollow circular structures were seen in the cytoplasm of step 17 and step 18 spermatids during stages V and VI. Kinesin immunofluorescence was observed in manchettes of steps 10-18 spermatids (stages X-VI). The stage-dependent apical Sertoli cell cytoplasmic dynein immunofluorescence, in conjunction with the previously reported orientation of Sertoli cell microtubules (slow-growing ends toward the lumen) and peak secretion of androgen-binding protein and transferrin, is consistent with the hypothesis that cytoplasmic dynein is involved in Sertoli cell protein transport and secretion. Further, the localization of cytoplasmic dynein and kinesin to manchettes is consistent with current hypotheses concerning manchette function.

Animals↗
PubMed1992

The anti-neoplastic activity of 2,3-dihydrophthalazine-1,4-dione and N-butyl-2,3-dihydrophthalazine-1,4-dione in human and murine tumor cells.

2,3-Dihydrophthalazine-1,4-dione derivatives demonstrated potent cytotoxicity against the growth of murine leukemia cells and human single cell suspension, i.e. Tmolt3 leukemia and HeLa-S3, as well as colon adenocarcinoma and KB nasopharynx. However, only select compounds demonstrated activity against bronchogenic lung, osteosarcoma and glioma growth. 2,3-Dihydrophthalazine-1,4-dione was active in vivo against L1210 leukemia, Lewis lung and Ehrlich ascites carcinoma growth. In L1210 cells the agents inhibited both DNA and RNA synthesis, and a few of the compounds were capable of inhibiting protein synthesis at 3 times their ED50 values. When 2,3-dihydrophthalazine-1,4-dione and N-butyl-2,3-dihydrophthalazine-1,4-dione were examined for their mode of action in the L1210 lymphoid leukemia cells, the sites of inhibition by the agents appear to be the de novo purine pathway at the enzymes IMP dehydrogenase and PRPP amido transferase. IMP dehydrogenase activity was inhibited at least 45% by 45 min at 100 microM concentration of drugs whereas the remaining enzymes that were affected by the drugs were not inhibited as early. Secondary sites were dihydrofolate reductase and thymidylate synthetase. The d(NTP) levels were also reduced specifically dATP and dCTP levels.

Animals↗
PubMed1992

The antineoplastic and cytotoxicity of benzohydroxamic acids and related derivatives in murine and human tumor cells.

Benzohydroxamic acids proved to be potent cytotoxic agents suppressing the growth of a number of murine and human cell lines grown in tissue culture, e.g. leukemia, colon, uterine and glioma. Selected compounds demonstrated activity against the growth KB nasopharynx, bronchogenic lung, osteosarcoma and skin cancer. In vivo activity against Ehrlich ascites carcinoma growth was shown with certain compounds. In L1210 cells compound 2 inhibited DNA synthesis significantly within 60 min. the site of action of the agent appears to involve the purine de novo synthesis pathway at PRPP amido transferase and IMP dehydrogenase. Dihydrofolate reductase and nucleoside kinase activities were inhibited by the agent. The levels of d(NTP)s in L1210 cells were reduced after drug treatment. The drug did not appear to affect the DNA template directly causing any damage which might alter transcription and replication nor was there any inhibition of HeLa topoisomerase activity by the drug. Thus the drug appears to be a metabolic inhibitor of nucleoside metabolism.

Animals↗
PubMed1992

The synthesis and anti-neoplastic activity of N2-isobutyryl-2'-deoxyguanosine-N7-cyanoborane derivatives.

N2-Isobutyryl-2'-deoxyguanosine-N7-cyanoborane derivatives were observed to be potent antineoplastic agents and to be active against a number of human tissue culture tumor cells, e.g. Tmolt3 leukemia, HeLa-S3 uterine carcinoma. Selective agents were active against colon adenocarcinoma, osteosarcoma and glioma growth. These agents preferentially inhibited both DNA and RNA synthesis of L1210 cells. De novo synthesis of purines was significantly inhibited at the regulatory sites of PRPP amido transferase and IMP dehydrogenase. Other sites of inhibition were thymidylate synthetase, OMP decarboxylase and thymidine kinases. The agents also significantly reduced deoxyribonucleotide levels and caused DNA strand scission.

Animals↗
PubMed1991

2,5-Hexanedione exposure alters the rat Sertoli cell cytoskeleton. I. Microtubules and seminiferous tubule fluid secretion.

2,5-Hexanedione (2,5-HD) is a testicular and nervous system toxicant with an unknown mechanism of action. In this study, the effects of 2,5-HD on seminiferous tubule fluid (STF) secretion, testis morphology, and tubulin distribution were examined. Charles River CD rats (200 g) were exposed to 1% 2,5-HD in the drinking water for 5 weeks followed by a 3-week recovery period. STF secretion was measured by efferent duct ligation, and testis cross sections were prepared at 2, 3, 3.43, 3.57, 3.86, 4, and 8 weeks after beginning exposure. A dramatic inhibition of STF secretion was observed between Weeks 3 and 4. The inhibition of STF secretion occurred following simultaneous changes in Sertoli cell and elongate spermatid morphology but prior to changes in round spermatid morphology. Also, alterations in seminiferous tubule tubulin distribution were observed with kinetics similar to those for changes in seminiferous tubule morphology. This temporal sequence suggests a model of 2,5-HD-induced injury in which populations of germ cells are differentially sensitive to impairment of Sertoli cell function.

Animals↗
PubMed1991

2,5-Hexanedione exposure alters the rat Sertoli cell cytoskeleton. II. Intermediate filaments and actin.

The effects of 2,5-hexanedione (2,5-HD) exposure on the expression of intermediate filament and actin proteins in adult rat testis was examined during progressive stages of testicular injury. The distribution of vimentin within testis cross sections was examined using immunohistochemistry while rhodamine-labeled phalloidin was used to localize filamentous actin. Keratin was not detected in immunoblots of intermediate filament proteins tested with an antikeratin antibody to investigate the possible reexpression of the prepubertal intermediate filament protein keratin in 2,5-HD-exposed adult testes. However, 2,5-HD exposure did result in a progressively abnormal distribution of actin and vimentin within the seminiferous epithelium with the appearance of a high-molecular-weight protein which was vimentin immunoreactive and not present in control testes.

Actins↗
PubMed1985

Two daily melatonin injections differentially induce nonshivering thermogenesis and gonadal regression in the mouse (Peromyscus leucopus).

Female white-footed mice (Peromyscus leucopus) were injected twice daily with 5, 10, 50, 100 micrograms melatonin (MEL) or saline. Injections were given for 7 weeks at 2 and 12 hours after lights-on under a long day (LD 16:8) photoperiod. Afternoon administration of MEL induced gonadal regression, although a dose of 50 micrograms or more was necessary to obtain a maximal response. A 5 micrograms MEL injection in the afternoon resulted in intermediate reproductive tract weights. In white-footed mice a morning MEL injection did not abolish the reproductive regression induced by an afternoon injection. Mice receiving 10, 50 or 100 micrograms MEL daily exhibited increased nonshivering thermogenesis (NST), irrespective of the timing of the injection. Daily injections of 5 micrograms MEL had little effect on NST. These observations suggest that "up and down regulation" of MEL receptors may not be important in P. leucopus. Further, the mechanism by which MEL controls reproduction is different from that for NST.

Animals↗
PubMed1985

Effects of timed melatonin injections on reproduction in pinealectomized Peromyscus leucopus.

Fifty reproductively mature female pinealectomized or sham-operated white-footed mice (Peromyscus leucopus) were injected daily for 7 weeks with 50 micrograms melatonin at 12 hr after lights on. The injections started either on the day following surgery or 2 weeks after surgery. All mice were maintained at room temperature under long-day photoperiod (LD 16:8). Pinealectomized and sham-operated mice injected immediately following surgery and sham-operated mice injected beginning 2 weeks after surgery had reduced reproductive tract weights (30 +/- 6, 33 +/- 6, and 33 +/- 3 mg, respectively) compared to the pinealectomized mice injected beginning 2 weeks after surgery (78 +/- 8 mg). In a second study 74 pinealectomized or sham-operated mice were injected at either 2, 7.5, 12, or 15 hr after lights on with 50 micrograms melatonin. Irrespective of surgical treatment, mice injected at 15 hr had a mean (+/- SE) reproductive tract weight (33 +/- 10 mg) which was substantially less than the 2-hr group (78 +/- 17 mg) while the 7.5- and 12-hr groups were intermediate (P less than 0.001). Pinealectomized and sham-operated animals responded similarly to melatonin injections at these four time points (P less than 0.35). The clearance rate of plasma melatonin after a single 50-micrograms melatonin injection or after 2 weeks of daily injections at either 2 or 12 hr after lights on was determined. Melatonin concentrations were determined using high-performance liquid chromatography and radioimmunoassay.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗