COMPARISON OF PLANT DNA CONTENTS DETERMINED BY FEULGEN MICROSPECTROPHOTOMETRY AND LASER FLOW CYTOMETRY

An improved procedure is reported for determining DNA amounts of plant nuclei. Nuclei stained with propidium iodide, isolated from chopped plant leaves, were passed through an Ortho Cytofluorograph with a Lexel model 95 argon laser (514 nm) and the fluorescence measured, integrated, and recorded using an Ortho 2140 Data Acquisition computer. All nuclear samples were mixed with nuclei of Sultan barley (2C DNA content = 11.12 pg [picogram]) as an internal standard. DNA contents of ten plant species, ranging from 2C = 1.7 pg to 36.1 pg measured by flow cytometry, correlated strongly (r = 0.99, slope = + 1.00) with DNA contents determined from Feulgen-stained nuclei of the same species using microspectrophotometry. The flow cytometric procedures were sufficiently sensitive to detect differences in DNA content between inbred lines of corn and their F1 hybrids. Our results obtained with improved procedures, specifically using propidium iodide as a fluorochrome and plant nuclei instead of chicken erythrocytes as an internal standard, demonstrate that laser flow cytometry can be a precise, rapid, and reliable method for determining nuclear DNA content of plants.     

Purification and characterization of monkey salivary mucin.

Highly purified mucin was prepared from monkey (Macaca arctoides) extraparotid saliva by sequential chromatography on Sephadex G-200 (followed by reduction and alkylation of void volume materials), Sepharose CL-2B with 6 M urea, and CM52 cellulose with 6 M urea. Purity was critically ascertained by anion exchange chromatography, ultracentrifugal analysis, isoelectric focusing, sodium dodecyl sulfate-polyacrylamide electrophoresis, and crossed immunoelectrophoresis. Use of crossed immunoelectrophoresis to examine mucin preparations has not been previously reported. This technique was useful for assessing purity and displaying charge and size microheterogeneity in the purified S-carboxymethylated mucin. Threonine and serine comprised 37.8% of the total amino acids while the oligosaccharide moiety contained N-acetyl-glucosamine, N-acetylgalactosamine, fucose, galactose, N-acetylneuraminic acid, and sulfate. Following alkaline borohydride treatment, the carbohydrate chains were found to be linked O-glycosidically between N-acetylgalactosamine and threonine (serine).     

Sleeping blood,tremor and paralysis: A trans-cultural approach to an unusual conversion reaction

An unusual conversion reaction and a related folk belief system are described in a Cape Verdean-American woman. A clinical approach is presented which stresses the need to negotiate between professional and popular explanatory models of illness. It is suggested that a significant factor in the successful management of this patient's symptoms was the acceptance of a mutually-understandable idiom for communication and treatment.     

Silver Staining for Nucleolar Organizing Regions of Vertebrate Chromosomes

Refinements to a simple, one-step silver staining technique for nucleolar organizing regions are described. These include fixation of silver stained material with sodium thiosulfate and standardization of silver development conditions for different groups of vertebrates. The central advantages to the method are that it is rapid, reliable, simple, and inexpensive. Additional benefits include (i) consistent and uniform silver staining of nucleolar organizing regions, (ii) few reduced silver deposits elsewhere on the chromosomes or on the slides, (iii) generally unaltered chromosome morphology after silver treatment, and (iv) relative permanence of Permounted preparations. The method works equally well on chromosomes made from cell cultures and from solid tissues of live specimens.     

Normative study of age variation in salivary progesterone profiles.

Daily luteal progesterone levels were measured for 124 regularly menstruating women, aged 18-44, by radioimmunoassay of steroid levels in saliva. A consistent pattern of age variation in luteal function was found, with the lowest levels of progesterone in the 18-19-year-old and 40-44-year-old groups, the highest values in the 25-34 year olds, and intermediate values in the 20-24 and 35-39-year-old groups. The striking similarity of this pattern of age variation with empirically and theoretically generated curves of apparent fecundability, suggests that age-related changes in ovarian function may underlie observed age variation in fecundability.     

Human Ovarian Function and Reproductive Ecology: New Hypotheses

A series of eight hypotheses is presented, based on the results of current research, concerning the responsiveness of the human ovary to constitutional and environmental variables. These hypotheses are motivated by a theoretical position that seeks to understand human reproductive physiology as the product of natural selection. The hypotheses are: (1) Ovarian responsiveness occurs along a graded continuum. (2) The graded continuum of response forms a final common pathway for various "stresses." (3) Ovarian function tracks energy balance, not simply nutritional status. (4) Ovarian function tracks aerobic activity independently of energy balance. (5) Additive interactions characterize the interaction of constitutional and environmental factors modulating ovarian function. (6) Reproductive maturation is synchronized with skeletal maturation, especially of the pelvis. (7) Peak ovarian function is not ordinarily achieved until the early twenties. (8) Late reproductive maturation is associated with a slower rise in indices of ovarian function with age, and a lower level of ovarian function in adulthood. Together, these hypotheses provide for two, non-exclusive theories of facultative modulation of female reproductive effort. One theory views ovarian function as responsive to the prospects for positive reproductive outcome as these may be affected by maternal age, maturation, energy balance, and activity level. The second theory views ovarian function as responsive in a similar way to the need to maintain long-term maternal energy balance.     

Radiolabeled octreotide. What lessons for antibody-mediated targeting?

Octreotide is a synthetic analog of the peptide hormone somatostatin (SMS). A wide variety of tumors express enhanced numbers of SMS receptors, notably neuroendocrine tumors and lymphomas, but also some of the more common adenocarcinomas. Octreotide contains only eight amino acids, some of which are in the (D) configuration in order to enhance the stability of the molecule in vivo. Tyrosine and DTPA-containing analogs of octreotide have been synthesized and labeled with iodine-123 and indium-111, respectively, with the intention of targeting SMS receptor-containing tumors for diagnostic purposes. Both radiopharmaceuticals demonstrate a high sensitivity and specificity for these tumors, indicating a clinical role for these agents in management of these diseases. Lessons can be learned from the success of these agents when designing improved antibody-based molecules. Tumor uptake of radiolabeled octreotide is very rapid, occurring within minutes of administration. Blood clearance is also rapid, such that tumors are soon visible even in areas of high blood background. An interesting finding has been the differences between the pharmacokinetics of the iodinated and indium-labeled species. Although the majority of 123I-Tyr3-octreotide undergoes hepatobiliary excretion, 111In-DTPAPhe1-octreotide is eliminated predominantly by the kidneys. These results suggest that the smallest possible antibody-like tracers are likely to have advantages over native immunoglobulins and conventional Fab-like fragments.     

Neuroleptic-induced oral movements in rats: methodological issues

In three separate experiments groups of rats were chronically administered neuroleptics in a variety of ways (chronic injections, subcutaneous implants, and decanoate injections) and examined for oral movements (OMs) in two different tests: in an open cage using a human observer, or in a plexiglas tube enclosure, where OMs were monitored both by a human observer and computerized video analysis system. These two testing methods showed different effects of neuroleptic administration. In the open cage, OMs tended to be enhanced during chronic neuroleptic exposure and to rapidly subside upon drug withdrawal. The enhanced OMs were especially present just after drug injections, when activity levels were low. In the observation tube environment, however, OMs tended to be low soon after drug treatments, and elevated upon withdrawal. Thus, the type of behavioral test used determines how neuroleptic-induced increases in oral activity should be interpreted.     

Aging exacerbates negative remodeling and impairs endothelial regeneration after balloon injury

Many older patients, because of their high prevalence of coronary artery disease, are candidates for percutaneous coronary interventions (PCI), but the effects of vascular aging on restenosis after PCI are not yet well understood. Balloon injury to the right carotid artery was performed in adult and old rats. Vascular smooth muscle cell (VSMC) proliferation, apoptotic cell death, together with Akt induction, telomerase activity, p27kip1, and endothelial nitric oxide synthase (eNOS) expression was assessed in isolated arteries. Neointima hyperplasia and vascular remodeling along with endothelial cell regeneration were also measured after balloon injury. Arteries isolated from old rats exhibited a significant reduction of VSMC proliferation and an increase in apoptotic death after balloon injury when compared with adult rats. In the vascular wall of adult rats, balloon dilation induced Akt phosphorylation, and this was barely present in old rats. In arteries from old rats, Akt-modulated cell cycle check points like telomerase activity and p27kip1 expression were decreased and increased, respectively, compared with adults. After balloon injury, old rats showed a significant reduction of neointima formation and an increased vascular negative remodeling compared with adults. These results were coupled by a marked delay in endothelial regeneration in aged rats, partially mediated by a decreased eNOS expression and phosphorylation. Interestingly, chronic administration of L-arginine prevented negative remodeling and improved reendothelialization after balloon injury in aged animals. A decreased neointimal proliferation, an impaired endothelial regeneration, and an increase in vascular remodeling after balloon injury were observed in aged animals. The molecular mechanisms underlying these responses seem to be a reduced Akt and eNOS activity.