Drug resistance and drug combination features of the human immunodeficiency virus inhibitor, BCH-10652 [(+/-)-2'-deoxy-3'-oxa-4'-thiocytidine, dOTC]

The heterosubstituted nucleoside analogue dOTC [( )-2'-deoxy-3'-oxa-4'-thiocytidine, BCH-10652] is a racemic compound structurally related to 3TC (lamivudine), but has the oxygen and sulphur in the furanosyl ring transposed. Both the enantiomers (-)dOTC (BCH-10618) and (+)dOTC (BCH-10619) had equivalent activity against wild-type strains of HIV-1 in C8166 T-cells (EC50 1.0-10.0 microM) and in PBMCs (EC50 0.1-3.0 microM). Investigation of the activity of dOTC and its enantiomers against laboratory strains of HIV-1 with defined resistance to 3TC, AZT (zidovudine), ddl (didanosine), PMEA (adefovir), nevirapine and saquinavir indicated that sensitivity was maintained (<3-fold change in EC50) in all cases, with the exception of HIV-1RF 3TC-resistant viruses. The degree of resistance recorded for dOTC (four- to sevenfold), (-)dOTC (five- to eightfold) and (+)dOTC (five- to >18-fold) against these M1841 or M184V mutants, was significantly less than that recorded for 3TC (>100-fold). In addition, the inhibitory effect of the compounds against clinical isolates of HIV-1 recovered from patients with suspected resistance to 3TC and AZT was investigated. Clinical isolates were genotyped using the Murex Line Probe Assay (LiPA) and subgrouped into wild-type, 3TC-resistant and dual 3TC/AZT-resistant, as well as undefined or mixed genotype populations. Compared with the mean EC50 values obtained with genotypically and phenotypically wild-type clinical isolates, the mean EC50 values calculated for isolates phenotypically resistant to 3TC or 3TC and AZT were only 2.6-, 1.6- and 8.2-fold higher for dOTC, (-)dOTC and (+)dOTC, respectively. When the rate of emergence of virus resistant to dOTC and its enantiomers in vitro was investigated, virus resistant to (+)dOTC was readily selected for (<10 passages), and a methionine (ATG) to isoleucine (ATA) amino acid change at codon 184 was identified. In contrast, virus resistant to dOTC and (-)dOTC took longer to appear (15-20 passages), with a methionine (ATG) to valine (GTG) amino acid change at position 184 identified in both cases. In addition, virus passaged 20 times in the presence of dOTC also had a partial lysine (AAA) to arginine (AGA) exchange at position 65. These viruses showed only low-level resistance to dOTC and its enantiomers, but were highly resistant to 3TC. The antiviral effects of dOTC in combination with the nucleoside RT inhibitors AZT, 3TC, d4T (stavudine) and ddl, the non-nucleoside RT inhibitor nevirapine and the protease inhibitors saquinavir, ritonavir and indinavir was investigated. Two-way drug combination assays were carried out in peripheral blood mononuclear cell (PBMC) cultures by measuring the reduction in p24 viral antigen levels, and data was analysed using the MacSynergy II program. dOTC in combination with 3TC or d4T showed a moderate synergistic effect while all other combinations had an additive interaction.

Comparison of a high power diode laser with the Nd:YAG laser using in situ wound strength analysis of healing cutaneous incisions

BACKGROUND AND OBJECTIVE

The laser-tissue interaction of a high power semiconductor diode laser was compared to the continuous wave neodymium yttrium aluminum garnet (Nd:YAG) laser by evaluating primary wound healing of cutaneous incisions in rats.

STUDY DESIGN/MATERIALS AND METHODS

Full thickness incisions were made in rat skin using a diode laser (805 nm, 10 W, contact mode), an Nd:YAG laser (1,064 nm, 10 W, contact mode), and a stainless steel scalpel blade (control). In situ wound breaking strength measurements were obtained at 7, 14, and 21 days using a specially designed tensiometer. Cross sectional area of non-disrupted wounds was calculated in two groups prior to testing to allow for calculation of tensile strength. Blinded histopathologic analysis was also performed.

RESULTS

Analysis of variance (P < or = 0.05) was used to determine differences in breaking strengths and tensile strengths due to incision method. There was no significant difference in the breaking strengths (group 1) or tensile strengths (groups 2 and 3) of the diode and Nd:YAG laser incisions. As predicted, breaking strengths and tensile strengths of scalpel blade incisions were significantly greater than those of incisions made with laser energy. Histopathologic evaluation revealed that through day 14, the degree of inflammation and collagen production was similar for diode and Nd:YAG laser incisions. Laser incisions had greater inflammation and a lag in fibroblast invasion and collagen production compared with scalpel incisions. By day 21, all incisions were similar in fibroblast population and collagen production, but laser incisions had slightly more inflammation than scalpel incisions.

CONCLUSION

In the primary wound healing model described, the tissue effect, cellular response, and development of wound strength were essentially the same for the high power diode laser at 10 W and the Nd:YAG laser at 10 W.

Prevalence of sexual abuse history in a sample of women seeking treatment for premenstrual syndrome

This study evaluated the prevalence and correlates of sexual abuse history among women seeking treatment for severe premenstrual syndrome (PMS). Of 77 women participating in a randomized clinical trial of non-pharmacological treatments for severe PMS, 42 were interviewed regarding their sexual abuse history. The interviewed women were a mean of 38 years old, and most were of European ancestry, heterosexual, married, employed and well-educated. At least one attempted or completed sexual abuse event was reported by 95% of the women, with 81% reporting completed penetration against their will and 85% of these sustaining physical threat or harm. Compared to prior studies of sexually abused women in general populations, these women were abused earlier in life, more frequently and by similar types of offenders. Most of the abused women (65%) were estimated to have post-traumatic stress disorder (PTSD). Most abused women (83%) had never disclosed the abuse to a health practitioner. The findings suggest that a history of sexual abuse, particularly in childhood or adolescence, may be extremely common among women seeking treatment for severe PMS, and that substantial undiagnosed PTSD may also be present in this population. Implications for patient screening and treatment are discussed.

Branched chain amino acids induce apoptosis in neural cells without mitochondrial membrane depolarization or cytochrome c release: implications for neurological impairment associated with maple syrup urine disease

Maple syrup urine disease (MSUD) is an inborn error of metabolism caused by a deficiency in branched chain alpha-keto acid dehydrogenase that can result in neurodegenerative sequelae in human infants. In the present study, increased concentrations of MSUD metabolites, in particular alpha-keto isocaproic acid, specifically induced apoptosis in glial and neuronal cells in culture. Apoptosis was associated with a reduction in cell respiration but without impairment of respiratory chain function, without early changes in mitochondrial membrane potential and without cytochrome c release into the cytosol. Significantly, alpha-keto isocaproic acid also triggered neuronal apoptosis in vivo after intracerebral injection into the developing rat brain. These findings suggest that MSUD neurodegeneration may result, at least in part, from an accumulation of branched chain amino acids and their alpha-keto acid derivatives that trigger apoptosis through a cytochrome c-independent pathway.

Symbiotic germination and development of myco-heterotrophic plants in nature: ontogeny of Corallorhiza trifida and characterization of its mycorrhizal fungi

The processes of symbiotic germination and seedling development were analysed in the myco-heterotrophic orchid Corallorhiza trifida, seeds of which were buried in 'packets' either adjacent to or at varying distances from adult plants in defined communities of ectomycorrhizal tree species. Germination occurred within eight months of burial under Betula-Alnus and within seven months under Salix repens. It was always associated with penetration of the suspensor by a clamp-forming mycorrhizal fungus. Four distinct developmental stages were defined and the rates of transition through these stages were plotted. There was no evidence of a relationship between extent of germination or rate of development and the presence of naturally distributed plants of C. trifida at the spatial scale of 1 m. The best germination and the most rapid rate of development of C. trifida seedlings occurred in a Salix repens community located at a considerable distance from any extant C. trifida population. Determination of internal transcribed spacer (ITS) RFLPs and of gene sequences of the fungi involved in symbiotic germination and growth of C. trifida, revealed them to belong exclusively to the Thelephora-Tomentella complex of the Thelephoraceae. These fungi are known also to be ectomycorrhizal associates of trees. It is hypothesized that the rate of growth of the C. trifida seedlings is determined by the ability of the fungal symbionts to transfer carbon from their ectomycorrhizal co-associates.

A comparison of the relative merits of radical perineal and radical retropubic prostatectomy

OBJECTIVE

To compare the outcome, advantages and disadvantages of retropubic and perineal approach to radical prostatectomy, as performed by one surgeon.

PATIENTS AND METHODS

This unrandomized study included 138 patients who underwent either radical retropubic (RRP) or radical perineal prostatectomy (RPP), based on the specific conditions or the patient's choice; 79 patients (mean age 64.6 years) underwent RPP and 59 (mean age 61.7 years) RRP. Outcome measures included estimated blood loss, the incidence of blood transfusions, positive margins and complications, operative duration, analgesic use, days in hospital and quality of life.

RESULTS

There was no difference in operative duration, and the incidence of positive margins or complications between the groups. The mean estimated blood loss in the RPP and RRP groups was 415 and 1,138 mL, respectively. The RPP group stayed a mean of 2.2 days less in hospital and took 2.8 days less to regain a full diet than the RRP group; the RPP group needed 1.7 days before using oral analgesics and the RRP group 3.8 days. Of patients in both groups, 85% were pad-free at one year and their overall quality of life was similar.

CONCLUSIONS

The results of RRP and RPP are comparable; the advantages of the perineal approach include minimal blood loss, low-intensity postoperative nursing care, low analgesic use and earlier discharge from hospital.

Changing women's health, changing nursing practice

Women's health is a field of study and health care that is of the highest concern for nurses, both from a professional and personal standpoint. It is imperative that those in nursing practice, education, and research be knowledgeable about, prepared for, able to advocate for, and participate in the transformation of health care policy and practice. The changing health care patterns and changing health care delivery system influencing the future of women's health are discussed. Recommendations for nursing practice, education, and research are proposed to advance women's health care.

Keratocytes generate traction forces in two phases

Forces generated by goldfish keratocytes and Swiss 3T3 fibroblasts have been measured with nanonewton precision and submicrometer spatial resolution. Differential interference contrast microscopy was used to visualize deformations produced by traction forces in elastic substrata, and interference reflection microscopy revealed sites of cell-substratum adhesions. Force ranged from a few nanonewtons at submicrometer spots under the lamellipodium to several hundred nanonewtons under the cell body. As cells moved forward, centripetal forces were applied by lamellipodia at sites that remained stationary on the substratum. Force increased and abruptly became lateral at the boundary of the lamellipodium and the cell body. When the cell retracted at its posterior margin, cell-substratum contact area decreased more rapidly than force, so that stress (force divided by area) increased as the cell pulled away. An increase in lateral force was associated with widening of the cell body. These mechanical data suggest an integrated, two-phase mechanism of cell motility: (1) low forces in the lamellipodium are applied in the direction of cortical flow and cause the cell body to be pulled forward; and (2) a component of force at the flanks pulls the rear margins forward toward the advancing cell body, whereas a large lateral component contributes to detachment of adhesions without greatly perturbing forward movement.

Community structure of ectomycorrhizal fungi in a Pinus muricata forest: minimal overlap between the mature forest and resistant propagule communities

We have investigated colonization strategies by comparing the abundance and frequency of ectomycorrhizal fungal species on roots in a mature Pinus muricata forest with those present as resistant propagules colonizing potted seedlings grown in the same soil samples. Thirty-seven fungal species were distinguished by internal transcribed spacer (ITS) restriction fragment length polymorphisms (RFLPs); most were identified to species level by sporocarp RFLP matches or to genus/family level by using sequence databases for the mitochondrial and nuclear large-subunit rRNA genes. The below-ground fungal community found in the mature forest contrasted markedly with the resistant propagule community, as only four species were found in both communities. The dominant species in the mature forest were members of the Russulaceae, Thelephorales and Amanitaceae. In contrast, the resistant propagule community was dominated by Rhizopogon species and by species of the Ascomycota. Only one species, Tomentella sublilacina (Thelephorales), was common in both communities. The spatial distribution of mycorrhizae on mature roots and propagules in the soil differed among the dominant species. For example, T. sublilacina mycorrhizae exhibited a unique bias toward the organic horizons, Russula brevipes mycorrhizae were denser and more clumped than those of other species and Cenococcum propagules were localized, whereas R. subcaerulescens propagules were evenly distributed. We suggest that species differences in resource preferences and colonization strategies, such as those documented here, contribute to the maintenance of species richness in the ectomycorrhizal community.

The actin-based nanomachine at the leading edge of migrating cells

Two fundamental parameters of the highly dynamic, ultrathin lamellipodia of migrating fibroblasts have been determined-its thickness in living cells (176 +/- 14 nm), by standing-wave fluorescence microscopy, and its F-actin density (1580 +/- 613 microm of F-actin/microm(3)), via image-based photometry. In combination with data from previous studies, we have computed the density of growing actin filament ends at the lamellipodium margin (241 +/- 100/microm) and the maximum force (1.86 +/- 0.83 nN/microm) and pressure (10.5 +/- 4.8 kPa) obtainable via actin assembly. We have used cell deformability measurements (. J. Cell Sci. 44:187-200;. Proc. Natl. Acad. Sci. USA. 79:5327-5331) and an estimate of the force required to stall the polymerization of a single filament (. Proc. Natl. Acad. Sci. USA. 78:5613-5617;. Biophys. J. 65:316-324) to argue that actin assembly alone could drive lamellipodial extension directly.

Anti-human immunodeficiency virus type 1 activity, intracellular metabolism, and pharmacokinetic evaluation of 2'-deoxy-3'-oxa-4'-thiocytidine

The racemic nucleoside analogue 2'-deoxy-3'-oxa-4'-thiocytidine (dOTC) is in clinical development for the treatment of human immunodeficiency virus (HIV) type 1 (HIV-1) infection. dOTC is structurally related to lamivudine (3TC), but the oxygen and sulfur in the furanosyl ring are transposed. Intracellular metabolism studies showed that dOTC is phosphorylated within cells via the deoxycytidine kinase pathway and that approximately 2 to 5% of dOTC is converted into the racemic triphosphate derivatives, which had measurable half-lives (2 to 3 hours) within cells. Both 5'-triphosphate (TP) derivatives of dOTC were more potent than 3TC-TP at inhibiting HIV-1 reverse transcriptase (RT) in vitro. The K(i) values for dOTC-TP obtained against human DNA polymerases alpha, beta, and gamma were 5,000-, 78-, and 571-fold greater, respectively, than those for HIV RT (28 nM), indicating a good selectivity for the viral enzyme. In culture experiments, dOTC is a potent inhibitor of primary isolates of HIV-1, which were obtained from antiretroviral drug-naive patients as well as from nucleoside therapy-experienced (3TC- and/or zidovudine [AZT]-treated) patients. The mean 50% inhibitory concentration of dOTC for drug-naive isolates was 1.76 microM, rising to only 2.53 and 2.5 microM for viruses resistant to 3TC and viruses resistant to 3TC and AZT, respectively. This minimal change in activity is in contrast to the more dramatic changes observed when 3TC or AZT was evaluated against these same viral isolates. In tissue culture studies, the 50% toxicity levels for dOTC, which were determined by using [(3)H]thymidine uptake as a measure of logarithmic-phase cell proliferation, was greater than 100 microM for all cell lines tested. In addition, after 14 days of continuous culture, at concentrations up to 10 microM, no measurable toxic effect on HepG2 cells or mitochondrial DNA replication within these cells was observed. When administered orally to rats, dOTC was well absorbed, with a bioavailability of approximately 77%, with a high proportion (approximately 16.5% of the levels in serum) found in the cerebrospinal fluid.

Increased nitric oxide synthesis is not involved in delayed cerebral energy failure following focal hypoxic-ischemic injury to the developing brain

This study addressed the hypothesis that the delayed impairment in cerebral energy metabolism that develops 10-24 h after transient hypoxia-ischemia in the developing brain is mediated by induction of increased nitric oxide synthesis. Four groups of 14-d-old Wistar rat pups were studied. Group 1 was subjected to unilateral carotid artery ligation and hypoxia followed immediately by treatment with the nitric oxide synthase (NOS) inhibitor, Nomega-nitro-L-arginine methyl ester (L-NAME, 30 mg/kg). Group 2 underwent hypoxia-ischemia but received saline vehicle. Group 3 received L-NAME without hypoxia-ischemia, and group 4, saline vehicle alone. At defined times after insult, the expression of neuronal and inducible NOS were determined and calcium-dependent and -independent NOS activities measured. Cerebral energy metabolism was observed using 31P magnetic resonance spectroscopy. At 48 h after insult, the expression of inducible NOS increased, whereas neuronal NOS at 24 h decreased on the infarcted side. Calcium-dependent NOS activity was higher than calcium-independent NOS activity, but did not increase within 36 h after insult, and was significantly inhibited by the administration of L-NAME. However, L-NAME did not prevent delayed impairment of cerebral energy metabolism or ameliorate infarct size. These results suggest that the delayed decline in cerebral energy metabolism after hypoxia-ischemia in the 14-d-old rat brain is not mediated by increased nitric oxide synthesis.

The role of Schizosaccharomyces pombe Rad32, the Mre11 homologue, and other DNA damage response proteins in non-homologous end joining and telomere length maintenance

The Schizosaccharomyces pombe homologue of Mre11, Rad32, is required for repair of UV- and ionising radiation-induced DNA damage and meiotic recombination. In this study we have investigated the role of Rad32 and other DNA damage response proteins in non-homologous end joining (NHEJ) and telomere length maintenance in S.pombe. We show that NHEJ in S.pombe occurs by an error-prone mechanism, in contrast to the accurate repair observed in Saccharomyces cerevisiae. Deletion of the rad32 gene results in a modest reduction in NHEJ activity and the remaining repair events that occur are accurate. Mutations in two of the phosphoesterase motifs in Rad32 have no effect on the efficiency or accuracy of end joining, suggesting that the role of Rad32 protein may be to recruit another nuclease(s) for processing during the end joining reaction. We also analysed NHEJ in other DNA damage response mutants and showed that the checkpoint mutant rad3-d and two recombination mutants defective in rhp51 and rhp54 (homologues of S.cerevisiae RAD51 and RAD54, respectively) are not affected. However disruption of rad22, rqh1 and rhp9 / crb2 (homologues of the S.cerevisiae RAD52, SGS1 and RAD9 genes) resulted in increased NHEJ activity. Telomere lengths in the rad32, rhp9 and rqh1 null alleles were reduced to varying extents intermediate between the lengths observed in wild-type and rad3 null cells.

Symptom responses of midlife Filipina Americans

OBJECTIVE

The purpose of this study was to describe the perimenopausal symptom responses of Filipino American midlife women.

DESIGN

This cross-sectional, descriptive survey collected symptom response information on Filipino American midlife women aged 35 to 56 years (n = 165) who self-identified as Filipina American and were proficient in the English language. Women were recruited from community churches and social groups. A survey questionnaire comprised of health history questions and a symptom checklist with symptom response questions were completed by the participants.

RESULTS

The symptom responses of women were compared by age groups of 35 to 39 (n = 39), 40 to 44 (n = 40), 45 to 49 (n = 37), and 50 to 56 (n = 49) and by perimenopausal phases of premenopausal (n = 85), transitional (n = 33), and menopausal/postmenopausal (n = 47). Indications from chi 2 tests showed that women in the 35-to-39- and 50-to-56-year groups were more likely to take acetaminophen (Tylenol) or aspirin for symptoms, and women in the 45-to-49- and 50-to-56-year groups were more likely to be on hormone replacement therapy. Surprisingly, women in the 50-to-56-year group were less likely to use talking with friends as a symptom management strategy.

CONCLUSIONS

Nonpharmacologic symptom management strategies exceeded the use of medications (hormones, over-the-counter) by Filipina Americans. This may be a strong indicator of their positive attitude toward this phase in their life and sends a message to clinicians about the choices that these women make for symptom management. Culturally relevant care would include alternatives to hormone replacement therapy in education materials about the perimenopausal transition for midlife Filipinas.

Symptom experience of Filipino American midlife women

OBJECTIVE

The purpose of this study was to describe the perimenopausal symptom experience of Filipino American midlife women with particular emphasis upon estrogen-related menopause symptoms (day sweats, hot flashes, night sweats, and vaginal dryness).

DESIGN

A cross-sectional, descriptive survey was used to generate symptom experience data for 165 Filipina Americans between the ages of 35 and 56 who self-identified as Filipina American and were English-language proficient. The community-based sample completed questionnaires composed of sample characteristic questions and a 51-item menstrual symptom checklist with menopause-related symptoms embedded in it.

RESULTS

Sample characteristics and symptom experience were compared among age groups of 35 to 39 (n = 39), 40 to 44 (n = 40), 45 to 49 (n = 37), and 50 to 56 (n = 49) and by perimenopausal phase, defined as premenopausal (n = 85), transitional (n = 33), and menopausal/postmenopausal (n = 47). The most reported individual symptoms were "felt energetic" (86.1%) and "well-being" (83.6%). Estrogen-related menopause symptoms were reported as "vaginal dryness" (39.4%), "hot flashes" (37.6%), "day sweats" (27.9%), and "night sweats" (24.2%) by the total sample. Distress associated with estrogen-related menopause symptoms was reported by 17% (n = 28) of all women. Subjects' chi 2 tests indicated that 50-to-56-year-old women were more likely to report fatigue/sleep symptoms, physical symptoms, and estrogen-related menopause symptoms than all other age groups. When compared by perimenopausal phase, transitional women were more likely to report moderate or extreme severity for day sweats. Premenopausal women were more likely to report minimal or mild severity and women in the perimenopausal transition were more likely to report moderate or extreme severity on estrogen-related menopause symptoms.

CONCLUSIONS

Filipino American midlife women appear to consider the perimenopausal transition in a positive light and experience little distress associated with estrogen-related menopause symptoms experienced. Findings from this study suggest that Filipina Americans view perimenopausal symptoms as part of a normal life stage that does not warrant concern.

Pyrido [1,2a] indole derivatives identified as novel non-nucleoside reverse transcriptase inhibitors of human immunodeficiency virus type 1

Pyrido [1,2a] indole derivatives were identified as potent inhibitors of human immunodeficiency virus type 1 (HIV-1) replication during a random screening programme. The compounds showed no antiviral activity against HIV-2 or in cells chronically infected with HIV-1, but had good inhibitory effect against purified HIV-1 reverse transcriptase (RT) in an in vitro assay. They were therefore classified as non-nucleoside RT inhibitors (NNRTI). The synthesis of additional compounds of the same class revealed a structure-activity relationship. The most potent compound of the series, BCH-1, had similar antiviral activity to the licensed NNRTI nevirapine against laboratory strains of HIV-1 cultured in cell lines and primary clinical isolates of HIV-1 cultured in peripheral blood mononuclear cells. However, BCH-1 showed greater cytotoxicity, providing a narrow selectivity index in the order of 35. BCH-1 had equivalent antiviral activity against viruses resistant to the nucleoside RT inhibitors zidovudine, didanosine and lamivudine and maintained better activity (less than threefold change in IC50) than nevirapine against viruses resistant to a range of NNRTIs with the single amino acid changes L100I, K103N, E138K or Y181C in the RT. Viruses with single V106A or Y188C amino acid changes showed five- and 10-fold resistance to BCH-1, respectively, in contrast to nevirapine, which had a > 100-fold change in IC50. However, virus with both V106A and Y188C amino acid changes showed higher level resistance (> 15-fold) to BCH-1. Virus with > 10-fold resistance to BCH-1 was rapidly selected for after growth in increasing concentrations of compound and was shown to be cross-resistant to nevirapine. Sequencing of this virus revealed two amino acid changes at positions 179 (V to D) and 181 (Y to C) in the RT. BCH-1 represents a new class of NNRTI, which may act as a lead to identify more selective compounds.

Poly(ADP ribose) polymerase cleavage precedes neuronal death in the hippocampus and cerebellum following injury to the developing rat forebrain

Transient unilateral forebrain hypoxia-ischaemia (HI) in 14-day-old rats produces infarction and delayed neuronal death in the frontal cortex. Cell death can also be observed in regions distant from the primary injury, a phenomenon known as diaschisis. While apoptosis is involved in selective neuronal death, its role in infarction and diaschisis remains poorly understood. Here, we have investigated the proteolytic cleavage of poly(ADP ribose) polymerase (PARP) and the occurrence of apoptosis in the hippocampus and the cerebellum following either HI or traumatic brain injury. We demonstrate that: (i) in vitro, PARP is cleaved during apoptosis but not necrosis in cultured neuronal (N1E) cells and Swiss 3T3 fibroblasts; (ii) following HI, apoptotic cells can be detected by 4 h after injury in the hippocampus; (iii) in the ipsilateral hippocampus the appearance of cells with apoptotic morphology is preceded by a dramatic increase in PARP cleavage in the same region, starting immediately following HI and persisting for 24 h; (iv) HI also induces apoptosis in the cerebellum and, as in the hippocampus, the appearance of cells with apoptotic morphology is preceded by PARP cleavage that is greater on the side ipsilateral to forebrain injury; and (v) similarly, traumatic brain injury to the forebrain leads to PARP cleavage and apoptosis in the cerebellum. We conclude that HI injury or traumatic injury to the developing rat forebrain leads to PARP cleavage in directly affected areas and in sites distant from the primary injury that precedes the appearance of cells with apoptotic morphology. Our results are consistent with a role for apoptotic cell death in infarction and in diaschisis resulting from forebrain injury to the developing brain.

Fluorescent-protein biosensors: new tools for drug discovery

Recent improvements in target discovery and high-throughput screening have increased the pressure at key points along the drug-discovery pipeline. High-content screening was developed to ease the bottlenecks formed at the target-validation and lead-optimization points, and a new generation of reagents that report on specific molecular processes in living cells (fluorescent-protein biosensors) have been important in its development. Creative designs of fluorescent-protein biosensors have emerged and been used to measure the molecular dynamics of macromolecules, metabolites and ions. Recent applications of fluorescent-protein biosensors to biological problems have provided a foundation for their use in biotechnology.

Isolation and characterization of the fungal metabolite 3-O-methylviridicatin as an inhibitor of tumour necrosis factor alpha-induced human immunodeficiency virus replication

The cytokine tumour necrosis factor alpha (TNF-alpha) has been shown to play a role in human immunodeficiency virus (HIV) replication by activating transcription of the provirus in both T cells and macrophages. Therefore, agents that block TNF-alpha-induced HIV expression could have therapeutic value in the treatment of AIDS. We have sought to identify antiviral agents that block TNF-alpha induction of HIV LTR-directed transcription, using a cell-based, virus-free assay system in automated high-throughput screening. HeLa cells were transfected with an HIV LTR-luciferase reporter plasmid and a stable line was isolated in which TNF-alpha increased luciferase production by two- to threefold. This cell line was used to screen approximately 15,000 fungal extracts. An inhibitory activity specific for TNF-alpha-induced HIV LTR transcription was observed in culture OS-F67406. The active component was isolated and identified as a known metabolite, 3-O-methylviridicatin, by NMR and mass spectrometry. No biological activity has been associated with this compound previously. This compound blocks TNF-alpha activation of the HIV LTR in the HeLa-based system, with an IC50 of 5 microM, and inhibited virus production in the OM-10.1 cell line, a model of chronic infection responsive to induction by TNF-alpha, with an IC50 of 2.5 microM.

Effects of probenecid on the elicitation of spreading depression in the rat striatum

Spreading depression (SD) is a wave of cellular depolarization which contributes to neuronal damage in experimental focal ischaemia, and may also underlie the migraine aura. The purpose of this study was to examine the effects of probenecid, an inhibitor of organic anion transport, on K+-evoked SD in vivo. Microdialysis electrodes were implanted in the rat striatum, and recurrent SD elicited by perfusion of artificial cerebrospinal fluid containing 160 mM K+ for 20 min. Probenecid was administered either directly through the microdialysis probe, starting 50 min before application of high K+, or intravenously. SD was markedly reduced by perfusion of 5 mM probenecid through the microdialysis probe. In contrast, a high intravenous dose of probenecid (250 mg/kg) only slightly inhibited SD elicitation 90 min after treatment, despite clear changes in the amplitude and spectrum of the electroencephalogram, as early as 10 min after drug administration, confirming that probenecid readily penetrated the central nervous system. As SD is inhibited by hypercapnia, we have examined the possibility that probenecid may inhibit SD through extracellular acidification subsequent to blockade of lactate transport. Perfusion of 1-20 mM probenecid increased dose-dependently the dialysate levels of lactate, but without extracellular acidosis since the dialysate pH was not significantly reduced. How probenecid inhibits SD deserves further investigation because it may help identify novel strategies to suppress this phenomenon, now recognized deleterious to neuronal function and survival.

Independent, specialized invasions of ectomycorrhizal mutualism by two nonphotosynthetic orchids

We have investigated the mycorrhizal associations of two nonphotosynthetic orchids from distant tribes within the Orchidaceae. The two orchids were found to associate exclusively with two distinct clades of ectomycorrhizal basidiomycetous fungi over wide geographic ranges. Yet both orchids retained the internal mycorrhizal structure typical of photosynthetic orchids that do not associate with ectomycorrhizal fungi. Restriction fragment length polymorphism and sequence analysis of two ribosomal regions along with fungal isolation provided congruent, independent evidence for the identities of the fungal symbionts. All 14 fungal entities that were associated with the orchid Cephalanthera austinae belonged to a clade within the Thelephoraceae, and all 18 fungal entities that were associated with the orchid Corallorhiza maculata fell within the Russulaceae. Restriction fragment length polymorphism and single-strand conformational polymorphism analysis of ectomycorrhizal tree roots collected adjacent to Cephalanthera showed that (i) the fungi associated internally with Cephalanthera also form typical external ectomycorrhizae and that (ii) ectomycorrhizae formed by other Basidiomycetes were abundant where the orchid grows but these fungi did not associate with the orchid. This is the first proof of ectomycorrhizal epiparasitism in nature by an orchid. We argue that these orchids are cheaters because they do not provide fixed carbon to associated fungi. This view suggests that mycorrhizae, like other ancient mutualisms, are susceptible to cheating. The extreme specificity in these orchids relative to other ectomycorrhizal plants agrees with trends seen in more conventional parasites.

Head and neck squamous cell growth suppression using adenovirus-p53-FLAG: a potential marker for gene therapy trials

The recombinant wild-type p53 adenovirus has been proven effective against the growth of human head and neck squamous cell cancer (SCCHN) cell lines iir vitro and in a nude mouse model. The addition of a FLAG peptide sequence was used in this study, along with the p53 adenovirus vector as a marker of the site of the gene therapy activity. It provides clear evidence of the exogenous gene product within the transduced carcinoma cells. No alterations in transcription or translation of the p53 gene product were noted with the addition of the FLAG sequence to the original p53 adenovirus vector. Immunohistochemical analysis displayed simultaneous expression of the p53 and FLAG proteins in the infected cells. The p53 protein remained localized to the nucleus, whereas the FLAG protein was additionally noted in the cytoplasm. In vitro growth suppression assays and in vivo microscopic residual tumor model experiments in nude mice showed a similar tumoricidal effect with the p53-FLAG adenovirus vector to that with the previously studied p53 adenovirus vector without the addition of the FLAG sequence. We conclude that the addition of the FLAG octapeptide sequence allows identification of those cells that have been affected by the molecular therapy independent of the endogenous gene expression of the cells. This novel molecular tracer may prove useful in characterizing infection efficiency and in gene therapy trials.

Traction forces of cytokinesis measured with optically modified elastic substrata

Animal cells dividing in culture undergo a dramatic sequence of morphological changes, characterized by cytoskeletal disassembly as cells round up, redistribution of actin, myosins and other cytoplasmic and surface molecules into the cleavage furrow, and respreading, before daughter cells finally separate at the mid-body. Knowledge of forces governing these movements is critical to understanding their mechanisms, including whether formation of the cleavage furrow results from increased force generation at the equator or relaxation at the poles, and whether traction force subsequently mediates cytofission of the intercellular bridge. We have quantitatively mapped traction forces in dividing cells, by extending the silicone-rubber substratum method to detect forces of nanonewtons to micronewtons. We used a new silicone polymer to fabricate substrata whose compliance can be adjusted precisely by ultraviolet irradiation. We show that traction force appears locally at the furrow in the absence of relaxation at the poles during cleavage. Force also rises as connected daughter cells respread and attempt to separate, suggesting that tension contributes to the severing of the intercellular bridge when cytokinesis is completed.

Changing women's health, changing nursing practice

Women's health is a field of study and health care that is of the highest concern for nurses, both from a professional and personal standpoint. It is imperative that those in nursing practice, education, and research be knowledgeable about, prepared for, able to advocate for, and participate in the transformation of health care policy and practice. The changing health care patterns and changing health care delivery system influencing the future of women's health are discussed. Recommendations for nursing practice, education, and research are proposed to advance women's health care.