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Biomedical subjects

D M Phillips

Publications and source records attributed to D M Phillips.

At least 37 records · Page 2Linked to original sources
PubMed1998

Carrageenan-based nonoxynol-9 spermicides for prevention of sexually transmitted infections.

BACKGROUND AND OBJECTIVES: Carrageenan-based nonoxynol-9 (N-9)-containing formulations were developed in response to the concern that over the counter (OTC) spermicides may not protect people from HIV infection and other sexually transmitted pathogens. GOAL OF THIS STUDY: The goal of this study was to compare the efficacy of carrageenan-based formulations to OTC spermicides in protecting mice from infection by herpes simplex virus 2 (HSV-2). STUDY DESIGN: Mice were challenged with vaginal inoculation of HSV-2 after pretreatment with test formulations. RESULTS: Carrageenan-based formulations were significantly more effective than currently marketed spermicides containing the same amount of N-9. Efficacy was demonstrated over a wide pH range. The carrageenan-based formulations could be autoclaved without losing antiviral activity and remained active in the vagina for several hours. CONCLUSIONS: We conclude that carrageenan-based N-9 formulations are likely to provide a more significant degree of protection against HSV-2 and other enveloped viruses than current OTC spermicides while providing comparable spermicidal activity.

Animals↗
PubMed1998

Phenylephrine, endothelin, prostaglandin F2alpha' and leukemia inhibitory factor induce different cardiac hypertrophy phenotypes in vitro.

In these studies, we show that endothelin (ET), leukemia inhibitory factor (LIF), phenylephrine (PE), and prostaglandin F2alpha (PGF2alpha), which are all hypertrophic for neonatal rat cardiac myocytes in culture, induce distinct morphological, physiological, and genetic changes after a 48-h treatment. Transmission electron microscopy revealed differences in myofibril organization, with ET-treated cells containing the most mature-looking myofibrils and PGF2alpha- and LIF-treated cells the least. ET- and PE-treated cultures contained the same number of beating cells as control, but LIF and PGF2alpha treatment increased the number of beating cells 180%. Treatment with LIF, PE, and PGF2alpha increased the beat rate to 3.3 times that of control. After exposure to the beta-adrenergic agonist isoproterenol, the beat rate increased 50% for PGF2alpha' 54% for PE, 84% for LIF, and 125% for control. ET treatment did not increase the beat rate, nor did these cells respond to isoproterenol. ET, LIF, and PE increased the production of atrial natriuretic peptide (ANP) by three-fold and PGF2alpha by 18-fold over nontreated cells. Brain natriuretic peptide (BNP) was increased fourfold by ET and PE, 16-fold by LIF, and 29-fold by PGF2alpha. Interestingly, on a pmol/L basis, only LIF induced more BNP than ANP. Treatment with all agents led to a similar pattern of gene induction: increased expression of the embryonic genes for ANP and skeletal alpha-actin, and less than a twofold change in the constitutively expressed gene myosin light chain-2, with the exception that LIF did not induce skeletal alpha-actin. Each agent, however, induced ANP mRNA with a different time-course. We conclude that at least four distinct cardiac myocyte hypertrophy response programs can be induced in vitro. Further studies are necessary to determine whether these correlate to the different types of cardiac hypertrophy seen in vivo.

Actins↗
PubMed1998

Mechanism of monocyte-macrophage-mediated transmission of HIV.

Observations from our laboratory support the theory that HIV-infected monocyte-macrophages present in genital tract secretions have an important role in sexual transmission of HIV. Light and electron microscopy were used to study the behavior of HIV-infected, primary human monocytes. These cells progress on surfaces, putting forward a leading pseudopod from which they secrete HIV. When added to cultures of CD4-, cervix-derived epithelial cells, monocytes advanced between epithelial cells while secreting virus anteriorly. Epithelial cells subsequently become productively infected. Infection of epithelia could be blocked by sera from HIV-seropositive individuals. These findings support the supposition that transmission of HIV may occur via cell-mediated infection of intact epithelia. The observations also hint at the possibility that HIV-infected monocyte-macrophages in semen or cervical-vaginal secretions could cross intact epithelia by passing between epithelial cells. To test this hypothesis supravital-stained mouse macrophages were inoculated into the vaginas of mice. Four hours later numerous stained cells were observed in the connective tissue beneath the vaginal epithelium and in the iliac lymph nodes. We speculate that direct infection of epithelial cells and/or cell trafficking across epithelia may be involved in sexual transmission of HIV.

Animals↗
PubMed1997

T-cell receptor zeta-chain expression on tumor-infiltrating lymphocytes from renal cell carcinoma.

Loss of the T-cell receptor-associated zeta chain in tumor-infiltrating lymphocytes (TILs) has been proposed as one mechanism of acquired immunosuppression in cancer patients. Recent reports suggest that zeta-chain loss may be related to contaminating monocyte/macrophage protease activity. Using flow cytometry and Western blot analysis, we have confirmed the expression of zeta chain in matched peripheral blood mononuclear cells and TILs from eight patients with primary renal cell carcinoma, when the cells were exposed to sufficient quantity of protease inhibitors. A small decrease in zeta-chain expression was found in three TIL samples. The loss of zeta-chain expression that was noted by others may be related to differences in laboratory method, and the small changes we have noted are unlikely to be sufficient in explaining the immunosuppression of TILs.

Biomarkers↗
PubMed1997

A role for cell migration in the sexual transmission of HIV-1?

The issue of how human immunodeficiency virus-1 (HIV-1) enters the body following sexual contact has been the subject of considerable controversy. Several possible routes for the initial infection have been suggested [1-6], including the possibility that the transmission is mediated by HIV-1-infected lymphocytes or macrophages in serum and female genital tract secretions, rather than by free virus. We recently reported that HIV-1-infected, activated primary monocytes can migrate between epithelial cells grown in confluent monolayer cultures in vitro [7]. We report here on experiments carried out in mice to test the hypothesis that mononuclear blood cells are capable of migrating through intact epithelia, and thus of carrying a virus into an animal. We placed double-stained, activated mononuclear blood cells into the vaginas of mice; four hours later, numerous double-stained cells were observed in the connective tissue beneath the vaginal epithelium and the iliac lymph nodes of the experimental mice. We speculate that such migration may be involved in the sexual transmission of HIV-1.

Animals↗
PubMed1997

Novel sperm crypts and behavior of gametes in the fallopian tube of the white-toothed shrew, Crocidura russula monacha.

The gametes of an insectivore, the white-toothed shrew, Crocidura russula monacha, present certain idiosyncratic features not seen in most other eutherian mammals. The spermatozoa display an acrosome of giant proportions, and are produced in relatively small numbers. In trans-illuminated oviducts examined with DIC optics, spermatozoa were first sequestered in languid clutches within the isthmus in deep narrow crypts, with some eventually ingested by the crypt epithelium. Then, at ovulation (ca. 15 hr after hCG), many ascended to occupy "bubble-like" ciliated crypts distributed randomly within the ampulla, as active groups of acrosome-intact spermatozoa. However, eggs (3.95; range 2-6) were first retained for several hours and were fertilized in an upper crypt-free infundibulum before moving down to the ampulla. At fertilization, individual spermatozoa penetrate an unusually compact matrix-free cumulus oophorus which is stabilized by intercellular junctions, is insensitive to hyaluronidase, and persists for approximately 13 hr around fertilized and for approximately 24 hr around unfertilized eggs. In contrast to the free ampullary spermatozoa, active spermatozoa accumulating within the cumulus all had shed the acrosome, an observation consistent with evidence from other shrews suggesting that the cumulus may necessarily induce the acrosome reaction in this ancient line. Hypertrophy of the acrosome, isthmic sperm storage crypts, and stable cumulus oophorus that develops a peri-zona space, all may prove to be typically crocidurine characteristics of use where the classification of a shrew is in doubt.

Acrosome↗
PubMed1997

Changes in the distribution of intermediate filaments in rat Sertoli cells during the seminiferous epithelium cycle and postnatal development.

BACKGROUND: Intermediate filaments (IFs) are components of the cytoskeleton. In mammalian Sertoli cell, IFs are formed by vimentin. Previous studies have shown some characteristics of its distribution in Sertoli cells, however, very little is known of its distributional changes during the seminiferous epithelium cycle and during postnatal development. METHODS: Immunohistochemical and electron microscopic methods were used to determine the distribution of vimentin-type IFs in rat Sertoli cells during the seminiferous epithelium cycle and postnatal development. RESULTS: The distribution of IFs in adult rat Sertoli cell showed distinct cyclic changes during the seminiferous epithelium cycle. At stages I-VI, bundles of IFs extend from the perinuclear region to the supranuclear and apical regions of the Sertoli cell. These apical extensions became shorter at stage VII, and at stages VIII-X IFs were observed only in the perinuclear region. Short apical extensions reappeared at stages XI-XII; and at stages XIII-XIV, they extended again into the apical region. During this cycle, IFs were always closely associated with the heads of elongate spermatids. IFs were also shown to be in close apposition to some specialized structures on the cell membrane, such as the ectoplasmic specialization between adjacent Sertoli cells. During postnatal (p.n.) development, IFs were mainly observed at the basal nuclear region on p.n. day 7. The IFs in the supranuclear or apical regions first appeared at p.n. day 14 and gradually increased during the development. The perinuclear IFs network was fully established by p.n. day 28 and the adult distribution pattern of the IFs was established by p.n. day 42. CONCLUSIONS: Vimentin-type IFs in rat Sertoli cells are a delicate endocellular network, which is centered in the perinuclear region and extends to the apical region of the cell. During the seminiferous epithelium cycle, the distribution of IFs changes in a stage-dependent manner and is closely related to the location of the heads of elongate spermatids. During postnatal development, IFs gradually increase in numbers and the main distribution area is transferred from the basal nuclear to the perinuclear and supranuclear regions.

Age Factors↗
PubMed1997

Giant, accordioned sperm acrosomes of the greater bulldog bat, Noctilio leporinus.

Sperm of the greater bulldog bat Noctilio leporinus display an architecture that is totally unique among mammalian spermatozoa. The sperm head of Noctilio is extraordinarily large and flat and lies eccentrically with respect to the sperm tail. The major portion of the atypically large acrosome lies anterior to the nucleus and is shaped into a dozen accordionlike folds that run parallel to the long axis of the sperm. The ridge of each fold is shaped into approximately 60 minute, evenly spaced rises that extend along the entire length of the fold. We speculate that acrosome ridges may serve to strengthen the sperm head during transport.

Acrosome↗
PubMed1997

Cell-mediated HTLV-I infection of a cervix-derived epithelial cell line.

There is considerable evidence that sexual transmission of human T-cell leukemia virus-I (HTLV-I) is mediated by virus-infected lymphocytes in genital tract secretions. However, it is not clear whether infection occurs through lesions in the genital tract epithelium or takes place via an intact epithelium. We have carried out experiments to test the hypothesis that sexual transmission of HTLV-I is initiated by lymphocyte-mediated infection of intact genital tract epithelia. To examine this question we added either free virus or HTLV-I producing MT-2 cells to cultures of a cervix-derived epithelial cell line, MS751. Although free virus did not infect MS751 cells, MS751 cells which had been coincubated with MT-2 cells became infected. These cultures produced about 50 pg/ml of HTLV-I p24 antigen per 10(6) cells over a 24 h period on the sixth day following exposure to donor T-cells. Proviral DNA could be detected in target MS751 epithelial cells by PCR. Infection of epithelia could be blocked, in a dose-dependent manner, by the sulfated polysaccharides dextran sulfate, heparin, and fucoidan, and by the enzymes fucosidase and mannosidase, but not by a number of other agents that were tested. Since MT-2 cells were observed to attach to the epithelial monolayer, we examined the ability of agents to inhibit adhesion. Adherence was inhibited by the same agents that inhibited infection. Based on these findings, we hypothesize that sexual transmission of HTLV-I may involve lymphocyte-mediated infection of genital tract epithelia and that lymphocyte adhesion to the epithelium is a critical event in transmission of HTLV-I. We speculate that a sugar moiety on the epithelium, possibly mannose or fucose, may be involved in adhesion of T-cells to epithelial cells. As sulfated polysaccharides block both adhesion and productive infection of the epithelium, these compounds might be used as active ingredients in a vaginal formulation to help prevent HTLV-I transmission.

Cell Adhesion↗
PubMed1997

Colposcopic evaluation of a vaginal gel formulation of iota-carrageenan.

There is an urgent need to develop safe, effective, and acceptable vaginal products for the prevention of sexually transmitted infections. Preliminary in vitro results suggest that vaginal formulations of sulfated polysaccharides, including iota-carrageenan, have the potential to block mucosal transmission of human immunodeficiency virus (HIV). Twenty-five women in five sites participated in Phase I trials to evaluate the safety of a formulation containing iota-carrageenan (PC 213). The results of this study indicate that a 5 mL 2% gel formulation of iota-carrageenan is not associated with significant irritation of the female reproductive tract when administered once daily in the absence of sexual intercourse. Given the small number of participants in this initial study, careful observation for potential irritation must also be included in larger studies of this and other vaginal formulations.

Administration, Intravaginal↗
PubMed1997

Unusual ampullary sperm crypts, and behavior and role of the cumulus oophorus, in the oviduct of the least shrew, Cryptotis parva.

The gametes of the least shrew, Cryptotis parva, were studied in regard to their maturation and structure, and with particular emphasis on their behavior in the fallopian tube, from the time of ovulation until the appearance of two-cell embryos beginning some 9 h after ovulation. Cryptotis spermatozoa are organized according to the conventional eutherian mold, with the exception of a barbed perforatorium and an unusual plasma membrane density lent by a bristly coat where it overlies the acrosome rim. In the epididymis they undergo a maturation of the capacity for motility and an -S-S-related stabilization of the nucleus and tail organelles, with the cauda housing only approximately 4-5 million spermatozoa. Mating involves penile locking and also the deposition of a modest vaginal plug that covers the cervix. The short (4-5 mm) fallopian tube has three regions-a simple isthmus, a relatively narrow ampulla populated throughout by ciliated crypts, and a crypt-free terminal infundibulum-the fertilization site. Unlike the situation in most mammals, the tubal isthmus was devoid of spermatozoa in mated females before and after ovulation, which occurred approximately 13 h post-hCG and produced a mean of 5.7 ova. However, the ampulla then housed approximately 1500 active cells in groups within the ciliated crypts, sometimes together with leukocytes but with few spermatozoa above in the infundibulum. Within about 1 h after their ovulation from approximately 400-microm follicles, eggs were penetrated while in the infundibulum despite the nonexpanded hyaluronidase-resistant state of the cumulus oophorus. However, on moving down to the ampulla by 2-4 h after ovulation, the dense cumulus around fertilized eggs appeared to proliferate and began to disperse coincidentally with secretion of a hyaluronidase-sensitive matrix in which hundreds of motile spermatozoa often became enmeshed. This cumulus change also occurred around unfertilized eggs, though more slowly, but not around fertilized or unfertilized eggs cultured in vitro. Thus, cumulus matrix production appeared to be stimulated to an important degree by factors in the oviduct, not by preovulatory gonadotropins as in many mammals. Although cumulus-invested eggs were fertilized readily in vitro, cumulus-free eggs of the same age were never fertilized, and spermatozoa bound to the zona pellucida had intact acrosomes. This and related evidence from other shrews makes it seem likely that the soricid cumulus has an essential role in fertilization and may induce the acrosome reaction.

Acrosome↗
PubMed1997

Vaginal formulations of carrageenan protect mice from herpes simplex virus infection.

The observations from the present study indicate that vaginal formulations of the sulfated polysaccharide carrageenan are highly effective in protecting mice from herpes simplex virus type 2 (HSV-2) infection. Test formulations were placed in the vaginas of progestin-treated mice prior to inoculation with HSV-2. Infection was determined by the presence of inflammation in the genital region and death. At a dose of virus that infected half of the control animals, 1% solutions of either lambda, kappa, or iota carrageenan prevented infection of almost all of the animals. Concentrations as low as 0.05% protected a large majority of the mice. At a dose of virus that infected all of the control mice, 1% solutions of carrageenans protected 85% of the inoculated mice. Other sulfated polysaccharides were less effective or showed no efficacy in preventing HSV-2 infection. These findings suggest that a vaginal formulation of carrageenan may be effective in blocking sexual transmission of HSV-2 in women.

Animals↗
PubMed1997

Follicle-stimulating hormone induces terminal differentiation in a predifferentiated rat granulosa cell line (ROG).

The divergent commitment of ovarian granulosa cells to either proliferation and differentiation or programmed cell death directly reflects the process of follicular dominance and atresia. This process is regulated by FSH and local paracrine factors. To further analyze the role of FSH and intraovarian factors in follicular selection, we have established a rat ovarian granulosa (ROG) cell line from prepubertal (p14) rats. ROG cells are cultured in serum-free medium with activin A, but without FSH. ROG cells bind FSH and respond to FSH by a burst of cell proliferation and increased progesterone secretion. These results support the hypothesis that activin, but not FSH, is an important factor in the maintenance of immature granulosa cells. After exposure of ROG cells to FSH, withdrawal of FSH from the cultures results in apoptotic cell death. ROG cells start active membrane blebbing by 2 h after FSH withdrawal, and most cells die within 7 h. Thus, FSH-induced ROG cells differentiate into a more mature granulosa phenotype, which is nonmitotic and dependent on FSH for survival. The ROG cell line may thus provide a good in vitro model of follicular selection.

Animals↗
PubMed1997

Establishing need for and designing information systems supporting decentralized services for the elderly: the case of Allegheny County, Pennsylvania.

Leaders of senior social services in Allegheny County, Pennsylvania, have reevaluated home-delivered meals (HDM) for the elderly in light of demographic and economic changes. A recommendation was the establishment of an integrated information system aiding policy and provider-level users in coordinating and planning numerous services, including HDM. The first step is the establishment of computerized geographic information and decision support systems. Further integration of a unified client database would enhance the capabilities of this information system in coordinating services for seniors. These possibilities, along with value-based and administrative challenges to constructing a countywide information system, are discussed.

Aged↗
PubMed1996

Current management of breast cancer.

Breast cancer accounts for more than 25 percent of all new cases of cancer in women. Family physicians have an important role in the management of patients who are diagnosed with breast cancer. The clinical staging system is a two-phase postsurgical process that assesses relevant prognostic factors and directs selection of adjuvant therapy after surgery. In stage I or II breast cancer, a patient's chances of disease recurrence and death depend on the number of cancer-positive regional lymph nodes at the time of diagnosis. Survival rates in patients with metastatic disease vary with the location and type of metastases. Whether surgery, chemotherapy or radiation therapy is chosen, patients and their families need continuous advice and support, especially when the cancer is advanced.

Breast Neoplasms↗
PubMed1996

Cell-mediated infection of cervix derived epithelial cells with primary isolates of human immunodeficiency virus.

We have previously demonstrated that HIV-infected transformed T-cells or monocytes adhere to monolayers of CD4-negative epithelial cells. Adhesion is soon followed by budding of HIV from infected mononuclear cells onto the surface of epithelial cells. Epithelial cells subsequently take up virus and become productively infected. Based on these findings, we proposed that sexual transmission of HIV may involve cell-mediated infection of intact mucosal epithelia of the urogenital tract. However, it has become increasingly clear that primary cells and HIV strains isolated from patients are more appropriate models for HIV infection than established cell lines and lab strains of virus. In the studies described here, we infected cervix-derived epithelial monolayers with primary monocytes infected with patient isolates of non-syncytial inducing (NSI) macrophage-tropic strains of HIV. Under the culture conditions employed, HIV-infected primary monocytes do not remain adherent to the apical surface of the epithelium, as did HIV-infected transformed cells. Instead, following adherence, the primary cells migrate between epithelial cells. Virus is secreted from a pseudopod as HIV-infected primary monocytes pass between cells of the epithelium. Productive infection of the epithelium was detected by p24 ELISA and PCR Southern blot analysis. Infection can be blocked by sera from HIV-seropositive individuals or by certain sulfated polysaccharides. These findings support the supposition that transmission of HIV may occur via cell-mediated infection of intact epithelia. The observations also hint at the possibility that-HIV-infected monocyte/macrophages in semen or cervical-vaginal secretions could cross intact epithelia by passing between epithelial cells. Blocking studies suggest that it may be possible to inhibit sexual transmission of HIV either by antibodies in genital tract secretions or by a topical formulation containing certain sulfated polysaccharides.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Sulfated polysaccharides inhibit lymphocyte-to-epithelial transmission of human immunodeficiency virus-1.

We have previously suggested that sulfated polysaccharides could be used in a vaginal formulation to inhibit infection by human immunodeficiency virus (HIV-1). This supposition was based on studies in which we developed and employed an in vitro model to simulate the mechanism of HIV-1 transmission during coitus. We found that adhesion of mononuclear cells to epithelia was the initial step in infection and speculated that blocking adhesion would prevent HIV-1 transmission. We observed that certain sulfated polysaccharides prevented adhesion of lymphoma cell lines to epithelial cell lines, which were derived from the genital tract, in concentrations of a few milligrams per milliliter; and we theorized that sulfated polysaccharides could thus be used as active ingredients in a topical "microbicide." In the present in vitro study, evidence is presented that a number of sulfated polysaccharides, including carrageenan, dextran sulfate, heparin, fucoidan, and pentosan polysulfate, are capable of blocking infection by mechanisms other than adhesion at concentrations of a thousand times lower than the dosages that are needed to block cell adhesion. One of these compounds, iota carrageenan, is capable not only of blocking infection of epithelia at concentrations of 1-2 micrograms, but of blocking adhesion to a far greater extent than the other sulfated polysaccharides tested. For this reason, as well as for considerations of safety, stability, and gelling properties, we suggest that iota carrageenan may be the best choice of the sulfated polysaccharides tested for use as a vaginal microbicide. The same in vitro model was employed to decipher the cell surface molecules involved in lymphocyte-to-epithelial adhesion. To accomplish this, we screened for the presence of cell adhesion molecules (CAMs), carbohydrates, proteoglycans, and carbohydrate-binding sites. HIV-1-infected lymphocytic cells expressed a CAM profile typical of activated, infected cells (e.g., HLA-DR+, CD4-, LFA-1+, ICAM-1+, LFA-3+, CD2+) whereas epithelia expressed few CAMs (LFA-3, ICAM-1, VLA-5, CD44, CD26, sLEX). Both cell types expressed heparan sulfate and chondroitin sulfate proteoglycans. A variety of sugars (mannose, fucose, galactose, Nac-galactosamine, Nac-glucosamine) were also present, but these cells expressed few carbohydrate-binding sites; lymphocytes bound beta-galactose. We were unable to block the adhesion with anti-CAM antibodies or with exogenous sugars. When enzymes were used against sulfated cell surface molecules, chondroitinase was found to block the adhesion. Our evidence suggests that this CAM-independent adhesion may be a lectin-glycosaminoglycan interaction.

Acquired Immunodeficiency Syndrome↗