Increasing nursing autonomy and recognition through shared governance.
Explore the source record for details and available documents.
Career Mobility↗
Biomedical subjects
L S Jones
Publications and source records attributed to L S Jones.
Relationship of intratesticular testosterone content of stallions to age, spermatogenesis, Sertoli cell distribution and germ cell-Sertoli cell ratios.
Testes were obtained from 47 1-20-year-old stallions during the natural breeding season. Total testicular testosterone and testosterone/g testis increased with age (P less than 0.005), and total testicular testosterone was associated with larger testis size (P less than 0.05). Neither testosterone per gram nor per paired testes were related to total Sertoli cell number (P greater than 0.05), but greater testosterone per paired testes was associated with fewer Sertoli cells per unit of seminiferous tubule length (P less than 0.005) or basement membrane area (P less than 0.02) and with a higher number of germ cells supported per Sertoli cell (P less than 0.05). Although values for testosterone per gram and per paired testes were unrelated (P greater than 0.10) to sperm production/g testis or to the yield of spermatids/spermatogonium, testosterone per paired testes was positively related to sperm production per paired testes (P less than 0.05). It is concluded that intratesticular testosterone increases with age, is related in a positive manner to quantitative rates of sperm production, and can account for some of the differences in sperm production among individual stallions within a single breeding season.
Aging↗
A calcium-activated, nonselective cationic conductance in Aplysia silent neurons.
We have previously reported the activation of a triphasic current response by calcium injection in voltage-clamped, nonbursting neurons of Aplysia californica. Present evidence indicates that the second phase, a delayed inward current that peaks 10-20 seconds after the end of the injection, is a calcium-activated, nonselective cationic conductance. It can be carried by both sodium and calcium, is not sensitive to chloride concentration changes, but is voltage sensitive, decreasing in amplitude with hyperpolarization.
Animals↗
Secretion of luteinizing hormone and follicle stimulating hormone in intact and ovariectomized mares in summer and winter.
Sequential samples of blood were drawn via jugular catheters every 15 min for 24 h from four mares in each of five reproductive states: intact anestrous mares in winter, intact diestrous mares in summer, intact estrous mares in summer, ovariectomized mares in winter and ovariectomized mares in summer. Estrous mares were sampled on d 4 or 5 of estrus and diestrous mares on d 10 or 11 of diestrus. Each sample of plasma was assessed for concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) in two independent radioimmunoassays. A computer program was developed that determined peak hormone concentrations based on assay sensitivity, assay variability and repeatability of peaks in both independent assays. Peaks in LH and FSH were observed for mares in all five reproductive states, except for FSH concentrations in estrous mares. High frequency peaks of short duration were observed only in ovariectomized mares. Low frequency peaks of relatively long duration were observed in both intact and ovariectomized mares in both seasons. With the exception of estrous mares, there was variation among mares in the patterns of LH and(or) FSH within any one group; all estrous mares exhibited high, variable LH concentrations and low, constant FSH concentrations. In general, peaks in both gonadotropins occurred simultaneously. Ovariectomized mares exhibited more (P less than .05) peaks/24 h than intact mares for both gonadotropins. Ovariectomized mares also exhibited more (P less than .05) FSH peaks/24 h in summer than in winter.
Animals↗
Occupational hazards for nurses exposed to radiation and antineoplastic agents.
Explore the source record for details and available documents.
Accidents, Occupational↗
A novel, calcium-induced triphasic current response in silent, non-bursting Aplysia neurons.
The iontophoretic injection of Ca2+ ions into voltage-clamped, silent neurons of Aplysia californica results in a prolonged, triphasic current response. This response consists of: a tetraethylammonium-sensitive outward current during the injection; followed by an inward current 10-30 s after the end of the injection; and finally a long, slowly increasing outward current that lasts for several minutes before returning to baseline.
Animals↗
Localization of alpha 1-adrenergic receptors in normal and weaver mouse brain with in vitro 125I-HEAT autoradiography.
Using 125I-HEAT, a specific alpha 1-adrenergic antagonist, we have autoradiographically localized alpha 1-adrenergic receptors in the normal and weaver mutant mouse. Highest levels of binding in both the normal and weaver mouse were seen in the dorsal thalamus, external plexiform layer of the olfactory bulb and intermediate layers of the frontoparietal cortex. These results essentially parallel those found in the rat, with some differences in the cortical pattern that are attributable to differences between the cytological organization in the two species. Reduced levels of binding in the agranular weaver cerebellum as compared to normals indicated that binding in the normal cerebellum was to receptors on granule cell dendrites.
Adrenergic alpha-Antagonists↗
A quantitative study of Sertoli cell and germ cell populations as related to sexual development and aging in the stallion.
Testes from 47 stallions, 1-20 yr of age, were used to examine the influence of age on Sertoli and germ cell populations as well as on functional activity of Sertoli cells. For these stallions, the number of Sertoli cells per paired testes declined linearly with age, and was only 41.7% as great at age 20 as at age 2. However, development of reproductive organs proceeded until age 12-13, as evident from increases in paired testes weight and quantitative rates of spermatozoal production. Although the absolute number of Sertoli cells declined during this period of development, individual Sertoli cells displayed a remarkable capacity to accommodate greater numbers of developing germ cells. Between age 2 and age 12, the mean numbers of developing spermatogonia, young primary spermatocytes, old primary spermatocytes, and round spermatids supported by each Sertoli cell at Stage I of spermatogenesis increased by 49, 176, 153, and 161%, respectively.
Aging↗
Active immunization of intact mares against gonadotropin-releasing hormone: differential effects on secretion of luteinizing hormone and follicle-stimulating hormone.
Five lighthorse mares were actively immunized against gonadotropin releasing hormone (GnRH) to determine the relative importance of this hypothalamic hormone in the secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Five mares immunized against the conjugation protein served as controls. Mares were initially immunized in November and received secondary immunizations 4 wk later, and then at 6-wk intervals until ovariectomy in June. All mares immunized against GnRH exhibited an increase (p less than 0.01) in the binding of tritiated GnRH by plasma, an indication that antibodies against this hormone had been elicited. Concentrations of LH, FSH and progesterone in weekly blood samples were lower (p less than 0.05) in GnRH-immunized mares than in controls after approximately 4 mo of immunization. However, the LH concentrations were affected to a greater degree than were FSH concentrations. All five control mares exhibited normal cycles of estrus and diestrus in spring, whereas no GnRH-immunized mare exhibited cyclic displays of estrus up to ovariectomy. All mares were injected intravenously with a GnRH analog (which cross-reacted less than 0.1% with the anti-GnRH antibodies) in May, after all control mares had displayed normal estrous cycles, to characterize the response of LH and FSH in these mares; two days later, the mares were injected with GnRH. The LH response to the analog, which was assessed by net area under the curve, was lower (p less than 0.01) by approximately 99% in mares immunized against GnRH than in control mares. In contrast, the FSH response to the analog was similar for both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Anestrus↗
Anatomy of brain alpha 1-adrenergic receptors: in vitro autoradiography with [125I]-heat.
Much useful information on the localization of alpha 1-adrenergic binding sites has been gained by using tritiated radioligands for in vitro autoradiography. However, the iodinated alpha 1-adrenergic antagonist HEAT [( 2-beta (4-hydroxyphenyl)-ethylaminomethyl)-tetralone], BE 2254), a radioligand with high affinity and specificity, provides autoradiographs with a higher signal to noise ratio. This has allowed us to describe the anatomy of these binding sites in much greater detail than previously possible. Regions showing the highest levels of binding include external plexiform layer of the olfactory bulb, layers Va and Vc of frontoparietal cortex, lateral and central amygdaloid nuclei, thalamus, and inferior olive. Other regions were generally less intensely labeled, with the least evidence of labeling in white matter, such as corpus callosum. Some regions (e.g., hippocampus) had only moderate labeling, but the binding appeared in a discrete pattern that reflected the functional organization of the structure. Although the [125I]-HEAT binding sites were distributed in a pattern similar to that previously reported for [3H]-WB 4101 and [3H]-prazosin, the anatomical detail seen with the iodinated ligand is greater. As a result, an association of alpha 1-adrenergic antagonist binding sites with specific layers in the cortex and with some catecholamine-containing nuclei in the brainstem, such as the locus coeruleus, have been seen for the first time.
Animals↗
Regional distribution of rat brain alpha 1-adrenergic receptors: correlation between (125I)-heat membrane binding and in vitro autoradiography.
[125I]-HEAT has proven useful for in vitro autoradiography as a specific alpha 1-adrenergic radioligand. We compared the binding of [125I]-HEAT to membranes from ten brain regions with the densitometric readings of these regions in autoradiographs. There was an excellent correlation between receptor numbers from membrane binding and relative optical densities from the autoradiography. The affinity of HEAT for binding to membranes from various regions was similar. The results of this direct comparison are further evidence that HEAT binds to alpha 1-adrenergic receptors in lightly fixed tissue sections. A further interesting observation is that in regions with a heterogeneous distribution of binding sites, membrane binding may not reflect the presence of a dense local population of receptors.
Adrenergic alpha-Antagonists↗
Postnatal development of brain alpha 1-adrenergic receptors: in vitro autoradiography with [125I]HEAT in normal rats and rats treated with alpha-difluoromethylornithine, a specific, irreversible inhibitor of ornithine decarboxylase.
The postnatal development of brain alpha 1-adrenergic receptors was studied in the rat brain using in vitro autoradiography. In some regions, such as the globus pallidus, receptor-binding sites were present at birth and increased during the first week but then decreased to very low levels by adulthood. In contrast, other regions such as the olfactory bulb and cerebral cortex exhibited little binding at birth, with a subsequent increase in receptors during the second week of life that persisted into the mature stage. Several regions had an intermediate pattern with significant labelling at birth, an increase in the first few weeks and a smaller decrement in binding sites as adulthood was approached. The data suggested that there were two archetypal development patterns, one of which was potentially related to the arrival of noradrenergic nerve projections (olfactory bulb) and the other of which was determined intrinsically by differentiation (globus pallidus). The two patterns could be distinguished by their sensitivity to alpha-difluoromethylornithine, a drug that inhibits ornithine decarboxylase, leading to a slowing of cellular replication, differentiation and migration. Drug treatment dramatically delayed the developmental fall-off of binding in the globus pallidus such that receptor sites remained in high concentration well past the point at which they disappeared in control animals. In the olfactory bulb, however, alpha-difluoromethylornithine had little or no effect on the ontogeny of receptor binding. These studies provide evidence that alpha 1-adrenergic receptors in various brain regions develop at different rates and with at least two characteristic patterns. Autoradiographic techniques provide important insights into receptor development that cannot be garnered from biochemical methods using isolated membrane preparations.
Adrenergic alpha-Antagonists↗
Assessment of treatment of intrahepatic malignancies using chemotherapy via an implantable pump.
Thirty patients in whom an implantable pump was used for hepatic arterial perfusion of chemotherapeutic agents to treat hepatic malignancy were evaluated. Three patients with primary hepatocellular carcinoma demonstrated less than 50% reduction in tumor size. One patient with metastatic gastric carcinoma and one patient with metastatic islet cell carcinoma also showed a decrease of less than 50% in the size of the tumor mass. Among the 25 patients with metastatic carcinoma from the colon or rectum, 23 had elevated carcinoembryonic antigen (CEA) levels before surgery and 75% of these revealed a reduction of at least 50%. Only three of 20 patients followed with sequential imaging studies showed a 50% decrease in the size of the tumor mass. No increase in the duration of survival could be defined when the treated patients were compared with 13 patients who had not received chemotherapy. The pump functioned well in all patients, but 77% showed signs of toxicity. This experience, coupled with a review of the literature, suggests that the procedure should be regarded as experimental and should not be applied liberally until a definite benefit can be demonstrated.
Adenoma, Islet Cell↗
Psychiatry in the medical curriculum.
When medical students of three universities, house surgeons, general practitioners, psychiatrists, and surgeons were asked in what order would they rank the importance of various subjects in the medical school education of a general practitioner, there is remarkable agreement regarding the first three. In all, 1402 respondents rank medicine, then pediatrics, then psychiatry as most important. There are differences which reflect cultural and curriculum diversity among the student groups. The majority of respondents believe psychiatry should occupy 11% or more of the curriculum.
Attitude of Health Personnel↗
Patterns of secretion of luteinizing hormone, follicle stimulating hormone and testosterone in stallions during the summer and winter.
Samples of jugular blood were drawn from each of five stallions every 15 min for 12 h during the summer and winter to determine the short-term fluctuations in plasma concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH) and testosterone. Concentrations of LH and FSH were generally not pulsatile, although one stallion exhibited three distinct pulses in these hormones during the winter. In general, patterns of secretion of all three hormones were similar in both seasons and the number of significant rises in hormonal concentrations did not differ between seasons. Concentrations of LH and FSH were positively correlated (P less than .05) for eight of the ten sampling periods, indicating a close relationship between the secretion rates of these two gonadotropins. Testosterone concentrations varied in an episodic manner during the 12-h period, and all stallions exhibited at least one episode of high testosterone secretion regardless of the pattern of LH concentrations. The response in testosterone concentrations to the three LH pulses exhibited by the one stallion in winter was not the same for each pulse. The correlations between a single random sample and mean concentrations over the 12-h period were high (r between .88 and .99) for all three hormones, indicating that a single sample of blood would be representative of overall concentrations. It appears that the stallion differs from males of other domestic species in that concentrations of gonadotropins and testosterone vary in a much less pulsatile manner.
Animals↗
Active immunization of prepubertal boars against testosterone: testicular and endocrine responses at 14 months of age.
Thirteen crossbred boars were immunized at 1 mo of age against either testosterone-3-oxime-equine serum albumin (treated boars) or equine serum albumin (control boars) to test the hypothesis that active immunization against testosterone stimulates testicular growth and development in the prepubertal boar. All boars were injected with the appropriate antigen at 2, 3, 4, 5 and 6 mo of age and were slaughtered at 14 mo of age. Active immunization against testosterone resulted in an increase (P less than .05) in tritiated-testosterone binding by plasma within 60 d after the primary immunization; the degree of binding decreased by 6 mo but remained elevated (P less than .05) relative to controls through 12 mo of age. There was no effect of treatment on body weights through 12 mo of age. Concentrations of testosterone in plasma were higher (P less than .05) in testosterone-immunized boars than in controls; this increase was likely due to antibody binding rather than increased testosterone secretion because (1) concentrations of androgen in testicular parenchyma at slaughter were not altered by treatment and (2) plasma concentrations of estrogens were generally not affected by treatment. Concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) were markedly suppressed in testosterone-immunized boars during the time when concentrations of these gonadotropins were high in control boars (greater than 3 mo of age). In spite of suppression of average LH and FSH concentrations, testicular weights, daily sperm production rates and seminal characteristics were similar for the two groups of boars at slaughter. (ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
The effect of auditory stimulus rate on [14C]2-deoxyglucose uptake in rabbit inferior colliculus.
The relationship between auditory stimulus rate and level of [14C]2-deoxyglucose (2-DG) uptake was examined using the 2-DG technique developed by Sokoloff as an indication of glucose uptake and neural activity. Conscious restrained albino rabbits were given one monaural tone either once per second or once per minute for 45 min, or served as unstimulated controls. Autoradiographs of the inferior colliculi from these animals were compared densitometrically. It was found that the rabbits stimulated once per second had markedly elevated levels of 2-DG uptake compared to both other groups: the rabbits stimulated once per minute and to unstimulated control rabbits. In addition, the inferior colliculus autoradiographs of the rabbits stimulated with pure tones showed a distinctive banding pattern in central nucleus different from that seen in control rabbits.
Acoustic Stimulation↗