Assessment of Habitat Modification and Varied Planting Dates to Enhance Potential Natural Enemies of Anasa tristis (Hemiptera: Coreidae) in Squash.

The squash bug, Anasa tristis (DeGeer) (Hemiptera: Coreidae), is an indigenous pest of squash and other cucurbits. Pesticides can control squash bug populations although many small-scale growers in the Southeast seek alternative methods of management. Cultural control methods, including varying the planting date and farmscaping, are not well understood under southeastern conditions. The goal of farmscaping is to increase natural ecosystem functions to aid in the control of pest populations. In the summers of 2014 and 2015, field plots of squash, separated by a minimum of 150 m were organized in a split-split plot design, with floral resources at the whole-plot level and varied planting date at the subplot level. Data were collected on squash bug abundance and fruit yield (kg), and abundance of potential natural enemies of A. tristis. Plots with added floral resources had fewer squash bug adults than plots without added floral resources in four of eight possible year × site × planting date combinations. Furthermore, the site in 2014 which had a reduction in squash bug adult abundance also had an increase in the abundance of potential enemies, including spiders, ground beetles, and predaceous Hemiptera. There were additional instances when potential natural enemy abundance was greater in resource-enhanced plots, but they were not associated with sites that had a reduction in yield loss or squash bug abundance. The use of floral resources to attract natural enemies and beneficial insects merits further investigation.

Cryopreserved embryos in the United States and their availability for research.

OBJECTIVE: To determine the number of embryos stored at assisted reproductive technology (ART) clinics in the United States and their current disposition. DESIGN: A targeted survey instrument sent by the SART-RAND team to all medical practices providing in vitro fertilization services in the United States. RESULTS: The SART-RAND team surveyed all 430 ART practices in the United States. Of these practices, 340 returned surveys for analysis. The data from these surveys were merged with data taken from the 1999 SART dataset, which contains information about practice size and success rates. Responding clinics reported a total of 396,526 embryos in storage as of April 11, 2002. The vast majority of the embryos (88.2%) were targeted for patient use. Small numbers of embryos were available for research, donation, destruction, quality assurance, or other uses. CONCLUSIONS: Nearly 400,000 embryos are stored in the United States, the majority of which (88.2%) are targeted for patient use. Few are available for research (2.8%), limiting possible conversion into embryonic stem cell lines.

Iris color and age-related changes in lens optical density.

PURPOSE: Epidemiologic evidence indicates that dark iris color increases risk of age-related cataract. No information is currently available, however, on the effects of iris color on the lens prior to cataract development. In this study, we relate iris color to lens optical density (OD) in individuals without frank cataract. METHODS: 90 subjects with blue or green irises (light color) were compared with 87 subjects having hazel, brown, or black irises (dark color). Lens OD was measured psychophysically by comparing scotopic thresholds obtained at 410 (measuring) and 550 nm (reference). Stimuli were presented in Maxwellian view. RESULTS: The groups with light and with dark iris color did not differ significantly in smoking habits, dietary patterns, or age. Despite other similarities between the groups, lens OD was significantly (p < 0.024) higher in the group with dark irises. The higher OD of the dark iris group was due to differences in the older subjects (> 45 years, p < 0.005), rather than the younger subjects (20-45 years) who showed no differences in lens OD. CONCLUSION: Our data indicate that iris pigmentation may be directly related to age-associated increases in lens OD.

Clonal distribution of osteoprogenitor cells in cultured chick periostea: functional relationship to bone formation.

Folded explants of periosteum from embryonic chick calvaria form bone-like tissue when grown in the presence of ascorbic acid, organic phosphate, and dexamethasone. All osteoblast-like cells in these cultures arise de novo by differentiation of osteoprogenitor cells present in the periosteum. To study the spatial and functional relationships between bone formation and osteoprogenitor cells, cultures were continuously labeled with [3H]thymidine for periods of 1-5 days. Radioautographs of serial 2-microns plastic sections stained for alkaline phosphatase (AP) showed maximal labeling of 30% of fibroblastic (AP-negative) cells by 3 days while osteogenic cells (AP-positive) exhibited over 95% labeling by 5 days. No differential shifts in labeling indices, grain count histograms of fibroblastic and osteogenic cells or numbers of AP-positive cells were observed, indicating no significant recruitment of cells from the fibroblastic to the osteogenic compartment. Despite the continuous presence of [3H]thymidine, less than 35% of both osteoblasts and osteocytes were labeled at 5 days, indicating that only one-third of the osteoprogenitor cells had cycled prior to differentiation. Spatial clustering of [3H]thymidine-labeled cells was measured by computer-assisted morphometry and application of the Poisson distribution to assess contagion. Cluster size and number of labeled cells per cluster did not vary between 1-3 days, but the number of clusters increased 20-fold between Day 1 and Day 3. Clusters were predominantly AP-positive and located close to bone. Three-dimensional reconstruction from serial sections showed that clusters formed long, tubular arrays of osteogenic cells up to eight cells in length and located within 2-3 cell layers from the bone surface. Selective killing of S-phase cells with two pulse labels of high specific activity [3H]thymidine at 1 and 2 days of culture completely blocked bone formation. These data indicate that a very small population of cycling osteoprogenitor cells is essential for bone formation in vitro and give rise to relatively small numbers of clonally distributed progenitors with limited proliferative capacity. The progeny of these clusters undergo restricted migration and differentiate into osteoblasts.

The regulatory effect of phosphates on bone metabolism in vitro.

One of the most important indicators in vitro of the bone-cell phenotype is the synthesis of mineralized bone-like tissue. This has been achieved by supplementing isolated bone-cell and tissue cultures with organic phosphates, in particular, beta-glycerophosphate. To analyze the effects of beta-glycerophosphate on bone-cell metabolism and osteogenesis in vitro, both biochemical analyses and computer-assisted morphometry were used. Simultaneous autoradiographic and histochemical analyses of proliferating and alkaline phosphatase-positive cells were used to measure osteogenic events at the cellular level. Morphometric data showed that beta-glycerophosphate-treated cultures mineralized, but exhibited significantly less bone matrix (P less than 0.05) than non-mineralizing controls. Cultures treated with inorganic phosphate failed to mineralize. Cellular proliferation was unaffected by beta-glycerophosphate; however, there was a decrease in the amount of 3H-thymidine incorporation into the DNA of beta-glycerophosphate-treated cells as detected by autoradiography. The percentage of alkaline phosphatase-positive cells was identical in beta-glycerophosphate-treated or control cultures. In agreement with previous biochemical results, there was a decrease in the amount of alkaline phosphatase enzyme activity per cell. The kinetics of alkaline phosphatase enzymes were measured on individual cells by microdensitometry. beta-Glycerophosphate-treated cultures exhibited more rapid reaction rates than control cultures (p less than 0.05). Taken together, the results suggest that beta-glycerophosphate has global effects on bone-cell metabolism in vitro including its importance in mineralization.

Site-specific regulation of osteogenesis: maintenance of discrete levels of phenotypic expression in vitro.

Intrinsic differences in bone formation rate, cell numbers, and the percentages of cells expressing alkaline phosphatase activity were studied in explants of chick calvaria periosteum cultured for 4 days and 6 days. Proliferation, differentiation, and bone production were examined in radioautographs of plastic sections and by using whole-culture biochemical assays of protein and alkaline phosphatase. Ectocranial explants at both 4 days and 6 days exhibited more alkaline phosphatase-positive cells and significantly more bone formation than endocranial cultures. There were no detectable differences in cell numbers or 3H-thymidine labeling indices. The volume of bone synthesized per osteoblast was significantly higher in the ectocranial group. Examination of bone stripped of periostea and then cultured for 4 days revealed that large areas of bone were covered by osteoblasts, indicating that the periosteal explant cultures were composed almost exclusively of osteoprogenitor cells and fibroblasts. The data suggest that the level of expression of predetermined osteogenic phenotypes can be maintained in vitro for 6 days following explantation and that variations in the rate of osteogenesis are programmed into progenitor cells prior to their differentiation into osteoblasts.

Brain lesions associated with nonfluent aphasia fifteen years following penetrating head injury.

Men who sustained penetrating head injuries resulting in nonfluent aphasia within six months following injury, were examined fifteen years later and classified into two groups, 13 with persistent nonfluent aphasia, and 26 without symptoms of aphasia. Relative to a normal control group on a comprehensive battery of speech and language tests, the chronic nonfluent aphasics demonstrated syntactic processing deficits in all language modalities, with only mild or no impairment in other language faculties. The recovered group demonstrated deficits only in written expressive syntax. The CT lesions of the two groups differed in the extent of left hemisphere lesion volume and the degree of posterior and deep lesion extension within the left hemisphere. The nonrecovered group did not have greater right hemisphere damage. Broca's area was equally involved in 77 per cent of patients in both groups. All patients in the nonrecovered group had posterior extension of their lesions in Wernicke's area with some involvement of the underlying white matter and basal ganglia in the left hemisphere.

Lesion locations associated with speech perception deficits following penetrating head injury.

Speech discrimination and identification tasks assessing voicing and place distinctions were given to 16 unilaterally brain injured subjects free of aphasic or dysarthric symptoms 12-15 yr post head injury. Seven subjects did not demonstrate any difficulty with these speech tasks, while five left- and four right-brain-injured subjects showed moderate difficulties. These difficulties were more pronounced on the discrimination than on the identification tasks. Analysis of CT scans demonstrated that the lesion locations most clearly associated with the speech discrimination deficits were upper levels of the white matter subjacent to cortical regions in either hemisphere.