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Biomedical subjects

P J Boyer

Publications and source records attributed to P J Boyer.

17 recordsLinked to original sources
PubMed1996

Identification of levels of maternal HIV-1 RNA associated with risk of perinatal transmission. Effect of maternal zidovudine treatment on viral load.

OBJECTIVE: To determine if there are levels of human immunodeficiency virus type 1 (HIV-1) associated with a high or low risk of perinatal transmission and to ascertain the mechanism by which zidovudine treatment reduces perinatal transmission. DESIGN: A nonrandomized prospective cohort study. SETTING: University medical center and two general hospital affiliates from May 1989 to September 1994. PATIENTS: Ninety-two HIV-1-seropositive women (95 pregnancies) and their 97 infants. INTERVENTION: Forty-two mothers (43 pregnancies) received zidovudine therapy during pregnancy and/or during labor and delivery. Eleven infants received prophylactic zidovudine for the first 6 weeks after delivery. MAIN OUTCOME MEASURE: HIV-1 infection status of the infant. RESULTS: Twenty of the 97 infants were perinatally infected with HIV-1. Transmitting mothers were more likely to have plasma HIV-1 RNA levels higher than 50000 copies per milliliter at delivery than nontransmitting mothers (15 [75.0%] of 20 transmitters vs four [5.3%] of 75 nontransmitters; P < .001). None of the 63 women with less than 20000 HIV-1 RNA copies per milliliter transmitted. Twenty-two women treated with open-label oral zidovudine during gestation showed an eightfold median decrease in plasma RNA levels (median [25th and 75th percentile], 43043 [5699 and 63053] copies per milliliter before zidovudine vs 4238 [603 and 5116] HIV-1 RNA copies per milliliter at delivery; P < .001) and none transmitted. Four zidovudine-treated women with high HIV-1 levels transmitted despite the presence of zidovudine-sensitive virus in vitro in both the mothers and their infants. CONCLUSIONS: Maternal HIV-1 RNA levels were highly predictive of perinatal transmission risk and suggest that certain levels of virus late in gestation and/or during labor and delivery are associated with both a high risk and a low risk of transmission. Our results also suggest that zidovudine exerts a major protective effect by reducing maternal HIV-1 RNA levels prior to delivery and that further strategies are needed to prevent perinatal transmission in women with high or increasing virus levels and/or zidovudine-resistant virus.

AIDS Serodiagnosis↗
PubMed1994

Sources of human Schwann cells and the influence of donor age.

We evaluated several tissues as possible sources for culturing human Schwann cells. The average cell yield (total cell number/mg of nerve fascicle) obtained from adult autopsy cases and transplant organ donors was similar (2 x 10(4) and 2.9 x 10(4), respectively), but significantly higher yields were obtained from dorsal roots of pediatric patients undergoing selective dorsal rhizotomy (6.1 x 10(4)). Fresh tissue was not essential since cells isolated from 0 to 20 h postmortem were equally viable. However, we found evidence that donor age affects the intrinsic growth rate of Schwann cells and perineurial fibroblasts in culture.

Adult↗
PubMed1993

The pharmacokinetics and safety of zidovudine in the third trimester of pregnancy for women infected with human immunodeficiency virus and their infants: phase I acquired immunodeficiency syndrome clinical trials group study (protocol 082). Zidovudine Collaborative Working Group.

OBJECTIVES: We measured the pharmacokinetics and safety of zidovudine in pregnant women infected with human immunodeficiency virus and their offspring. STUDY DESIGN: Asymptomatic human immunodeficiency virus-infected women with uncomplicated singleton gestations (28 to 36 weeks) underwent parenteral and oral zidovudine treatment during pregnancy and labor. Maternal and neonatal drug levels were measured at delivery and sequentially for 48 hours. Infants were followed up for 18 months. RESULTS: The total body clearance (26.3 +/- 10.1 ml/min/kg), mean terminal elimination phase zidovudine half-life (1.3 +/- 0.2 hours), and urinary zidovudine recovery were similar to values in nonpregnant adults. Essentially equivalent zidovudine levels in the mother and neonate at delivery implied little, if any, fetal zidovudine metabolism. The half-life of zidovudine in the neonates was tenfold that of the mother. No significant adverse effects were noted in the infant at birth or on follow-up. CONCLUSIONS: In both mothers and infants the drug appeared safe and well tolerated with no significant hematologic abnormalities.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Investigation of dysmyelinogenesis in caprine beta-mannosidosis: in vitro characterization of oligodendrocytes.

Central nervous system myelin deficiency is a consistent feature of caprine beta-mannosidosis, an autosomal recessive neurovisceral lysosomal storage disease. To investigate the possibility of an intrinsic oligodendrocyte defect in beta-mannosidosis, oligodendrocyte-enriched glial cultures from the cerebral hemisphere white matter of two affected and six control goats were compared with respect to culture yield and morphology. Fewer oligodendrocytes were cultured per gram of white matter from affected animals than from control animals. Galactocerebroside-positive oligodendrocytes from all animals were similar morphologically at all stages of culture by phase contrast and fluorescence microscopy. These findings are consistent with in vivo morphological observations and suggest that differentiated oligodendrocytes from affected animals do not show morphological abnormalities in culture. However, increased numbers of galactocerebroside-negative bipolar cells, which may be glial progenitor cells, were present in cultures from affected animals. This observation suggests the possibility of a defect in differentiation to mature oligodendrocytes, with persistence of the undifferentiated glia during late stages of development.

Animals↗
PubMed1990

Regional central nervous system oligosaccharide storage in caprine beta-mannosidosis.

Goats affected with beta-mannosidosis, an autosomal recessive disease of glycoprotein metabolism, have deficient activity of the lysosomal enzyme beta-mannosidase along with tissue storage of oligosaccharides, including a trisaccharide [Man(beta 1-4)GlcNAc(beta 1-4)GlcNAc] and a disaccharide [Man(beta 1-4)GlcNAc]. CNS myelin deficiency, with regional variation in severity, is a major pathological characteristic of affected goats. This study was designed to investigate regional CNS differences in oligosaccharide accumulation to assess the extent of correlation between oligosaccharide accumulation and severity of myelin deficits. The concentrations of accumulated disaccharide and trisaccharide and the activity of beta-mannosidase were determined in cerebral hemisphere gray and white matter and in spinal cord from three affected and two control neonatal goats. In affected goats, the content of trisaccharide and disaccharide in spinal cord (moderate myelin deficiency) was similar to or greater than that in cerebral hemispheres (severe myelin deficiency). Thus, greater oligosaccharide accumulation was not associated with more severe myelin deficiency. Regional beta-mannosidase activity levels in control goats were consistent with the affected goat oligosaccharide accumulation pattern. The similarity of trisaccharide and disaccharide content in cerebral hemisphere gray and white matter suggested that lysosomal storage vacuoles, more numerous in gray matter, may not be the only location of stored CNS oligosaccharides.

Animals↗
PubMed1990

Caprine beta-mannosidosis. Abnormal thyroid structure and function in a lysosomal storage disease.

Deficient activity of the lysosomal enzyme beta-mannosidase leads to widespread tissue accumulation of oligosaccharides in caprine beta-mannosidosis, an autosomal recessive neurovisceral storage disease. Severe thyroid morphologic abnormalities found in a previous light microscopic survey of tissues from neonatal affected goats suggested the possibility of impairment of function. Since considerable evidence indicates that thyroid hormone plays an important role in regulation of myelination, thyroid hormone deficiency, if present during central nervous system development, could be a factor in the hypomyelination seen in affected animals. Thus, this study was designed to characterize thyroid structure and function in beta-mannosidosis. To investigate developmental aspects of structural abnormalities, thyroids from six pairs of affected and control animals ranging in age from 96/150 days gestation to 3 days postnatal were analyzed by light and electron microscopy. Major findings in thyroids from affected animals, as early as 96/150 days gestation, included follicle irregularities and pronounced presence of lysosomal storage vacuoles in all cell types, particularly in follicular cells. The degree of cytoplasmic vacuolation increased with advancing age. To assess thyroid function, thyroid hormone concentrations were determined in six age-matched, neonatal pairs of affected and control goats. Significantly decreased thyroid hormone concentrations were present in affected animals. It is hypothesized that thyroid hormone deficiency plays a role in the pathogenesis of hypomyelination in affected animals. This study comprises, to our knowledge, both the most complete description of developmental abnormalities and the first report of abnormal function in an endocrine organ in a lysosomal storage disease. Further, this report suggests that systemic perturbations induced by a genetically determined deficiency of a lysosomal hydrolase could be a factor in the pathogenesis of central nervous system lesions.

Aging↗
PubMed1989

Lymphocyte activation by recombinant interleukin-2 in ovarian cancer patients.

Peripheral blood lymphocytes from 42 patients and peritoneal cavity lymphocytes from eight patients with advanced ovarian carcinoma were tested for lymphokine-activated killer lymphocyte cytotoxicity against several ovarian carcinoma lines before and after exposure to recombinant interleukin-2 in vitro for 3-5 days. Only four of 42 (9.5%) of peripheral blood lymphocytes and zero of eight (0%) of peritoneal cavity lymphocytes had spontaneous cytotoxicity (greater than 20%) against the ovarian carcinoma lines. After in vitro exposure to recombinant interleukin-2, 41 of 42 (98%) of patients' blood lymphocytes showed a two- to fivefold increase in cytotoxicity against K562 (a lymphoblastoid human target), and 40 of 42 (95%) demonstrated lymphokine-activated killer cytotoxicity (greater than 20%) to the ovarian carcinoma lines. Lymphokine-activated killer activity against fresh allogeneic cell lines was variable, although most patients' peripheral blood lymphocytes (70%) had significant cytotoxicity. By contrast, incubation of patients' peritoneal cavity lymphocytes with recombinant interleukin-2 in vitro did not result in the generation of lymphokine-activated killer cell activity against K562 or ovarian cell lines. Peritoneal lymphocytes did produce lymphokine-activated killer cells in the presence of OK432 in half of the patients tested. The presence of autologous serum during recombinant interleukin-2 activation with blood lymphocytes had an augmentative effect on the resulting lymphokine-activated killer cytotoxicity in two of 20 patients, a suppressive effect in four of 20, and no effect in the other 14 of 20 patients tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1987

Dysmyelinogenesis in caprine beta-mannosidosis: ultrastructural and morphometric studies in fetal optic nerve.

The optic nerves from a goat fetus affected with beta-mannosidosis and a control fetus were analysed morphologically in order to investigate developmental aspects of beta-mannosidosis-associated myelin deficits. In the affected fetus, the number of myelinated axons per unit area was about 25% of the control values. Histograms of axonal diameter indicated that a greater percentage of the myelinated and unmyelinated axons were of larger caliber in the affected fetus than in the control fetus and that very few small axons were myelinated in the affected animal. The mean values of myelin sheath thickness in the affected and control animals did not differ significantly. Ultrastructural analysis revealed a decreased proportion of oligodendrocytes and an increased proportion of astrocytes in the affected fetus. These results indicate that the pathogenetic process leading to cellular abnormalities and myelin deficits in beta-mannosidosis has been initiated prior to 124 days gestation, during an early stage of myelination in the goat optic nerve. The decrease in number of oligodendrocytes suggests that early cell death and/or change in oligodendrocyte proliferation contribute to the myelin deficit. Analysis of the prenatal development of lesions will help clarify the pathogenesis of dysmyelinogenesis in beta-mannosidosis.

Animals↗
PubMed1979

Distribution and consequences of cell suspensions following intralymphatic infusion.

The fate and consequences of intralymphatic injections of cells was investigated in dogs. The distribution of intact radiolabeled cells was determined in vivo by whole body gamma scanning. Comparison of distributions resulting from intralymphatic, subcutaneous, intradermal and intravenous routes of administration showed that the distribution and duration of radiolabel in various organs varied with the route of administration. Following intralymphatic injection, radiolabel was concentrated in first echelon lymph nodes draining the site of injection and was retained in these nodes for over 4 weeks. Histologic studies showed intense cortical and paracortical lymphopoiesis to be associated with the retention of intralymphatically injected tumor cells by first echelon lymph nodes. Serial histologic examination of lymph nodes from intralymphatically injected inbred beagles revealed that the consequent lymphopoiesis persisted for 5 weeks. In vitro evaluation of peripheral blood and lymph node lymphocyte cytotoxicity to the injected cells indicated that retention and nodal lymphopoiesis was associated with the development of direct lymphocyte cytotoxicity. The effects of concommitant tumor burden, cytotoxic drugs and ionizing radiation were also investigated and suggest that the therapeutic potential for use of the intralymphatic route has not yet been realized.

Animals↗
PubMed1978

A phase I study of active specific intralymphatic immunotherapy (ASILI).

Twenty-one patients with advanced malignancies who had exhausted or refused conventional modalities of treatment were entered in a Phase I toxicology trial of active specific intralymphatic immunotherapy (ASILI). The patients were immunized with 1 X 10(7) to 1.2 X 10(8) viable autochthonous or allogeneic irradiated tumor cells intralymphatically each month and received no other antineoplastic treatment. To date, 274 intralymphatic injections have been performed and except for one case of bacterial lymphangitis, no adverse side effects have been observed. ASILI did not significantly alter peripheral blood lymphocyte counts, absolute E-rosette forming cell levels, or EA-rosette forming cell levels. PHA reactivity of peripheral blood lymphocytes increased slightly in all but one patient tested. Seven out of nine patients who had not had delayed hypersensitivity to recall antigens developed positive reactions following ASILI. Sixteen out of twenty patients tested also developed reactivity to their immunizing cells after treatment. Objective regression (greater than 50% reduction of tumor mass) was observed in five out of nineteen evaluable patients. Six patient showed stabilization of tumor growth and eight patients continued to progress under treatment.

Adult↗
PubMed1977

Regional intralymphatic infusion (ILI) of irradiated tumor cells with evidence of distant effects.

A case of canine lymphoma with radiographically-documented involvement of the para-aortic nodes is reported. Intralymphatic infusions (ILI) of cultured irradiated autochthonous tumor cells to remote lymph node bearing areas were associated with a dramatic initial shrinkage of the para-aortic lymphadenopathies. Three ILI timing schedules were used consecutively during a course of 10 treatments, allowing a comparison of responses in the same animal. The reported case suggests that a normal lymph node can be effectively "stimulated" by the same agent approximately every 3 weeks. A possible schedule for intralymphatic infusion is proposed for further investigation.

Animals↗
PubMed1976

Secondary in vitro lymphocyte-proliferative responses to syngeneic plasma cell tumors.

Two characteristics of immune responses to weakly immunogenic plasma cell tumors were demonstrated in this study. (a) Elevated lymphoproliferative responses following in vivo inoculation of sublethal doses of plasma cell tumors were detected by a mixed lymphocyte-tumor interaction (MLTI) assay. Specificity of elevated MLTI responses correlated with resistance to in vivo tumor challenge. These responses were dependent upon the presence of thymus-derived cells. (b) Spleen and lymph node cells showed markedly different patterns of MLTI activity following plasma cell tumor immunization. Spleen cell responses were depressed for the first 30 days postimmunization, whereas lymph node cells showed augmented MLTI reactivity immediately after immunization. These observations indicated that lymphocyte populations from different lymphoid organs may show widely dissimilar responses in vitro at the same point in the in vivo development of tumor resistance.

Animals↗
PubMed1976

Stimulation of lymphoid cells from normal and immune mice by syngeneic BALB/c plasma cell tumors.

Lymphoid cells from normal and immunized BALB/c mice could be stimulated in vitro by syngeneic PCT contrasted with an absence of response to a number of other tumors. Maximal responses of normal cells to PCT were found to occur 5 days after the initiation of the cultures at an optimal responding:stimulation cell ratio of 1:2. MLTI activity of normal cells could not be blocked or enhanced by PCT myeloma protein products indicating that MLTI reactivity was directed against non-idiotypec cell surface determinants. Lymphoid cells from immunized mice demonstrated increased MLTI responses to cells of the immunizing tumor but not to other PCT, indicating that the post-immunization MLTI responses were primarily to individual rather than shared tumor cell surface antigens. Activity of both normal and immunized spleen cells was found to involve thymus-derived lymphocytes. The persistence of residual MLTI activity after treatment with anti-theta serum and complement, however, implicated participation of non-theta antigen-bearing cells in MLTI reactivity. From these data, we conclude that lymphoid cells from un-immunized mice are capable of T cell-dependent reactivity to syngeneic PCT-associated antigens and that elevations in these reactivities after immunization may reflect specific cellular immune responses.

Animals↗
PubMedDate not supplied

Factors predictive of maternal-fetal transmission of HIV-1. Preliminary analysis of zidovudine given during pregnancy and/or delivery.

OBJECTIVE: To assess maternal risk factors potentially influencing vertical transmission of human immunodeficiency virus, type 1 (HIV-1), including maternal CD4 cell count; presence of immune complex dissociated (ICD) p24 antigen; maternal zidovudine therapy during pregnancy and/or delivery; complications of pregnancy, such as preterm labor and birth; and obstetric events during labor and delivery, such as duration of labor, mode of delivery, chorioamnionitis, and maternal blood exposure. DESIGN AND SETTING: A nonrandomized prospective cohort study at a university medical center and two general hospital affiliates. PATIENTS: Sixty-three HIV-1-seropositive pregnant women and their 68 infants. INTERVENTION: Twenty-six mothers received zidovudine therapy during pregnancy and/or during labor and delivery. MAIN OUTCOME MEASURE: HIV-1 infection status of the infant. RESULTS: Thirteen of the 68 infants were vertically infected with HIV-1. Mothers with events involving fetal exposure to maternal blood were more likely to transmit infection (four [31%] of 13 vs three [5%] of 55, P = .02), as were women with plasma ICD p24 antigenemia at delivery (six [67%] of nine vs 11 [25%] of 44, P = .02). Zidovudine treatment was associated with a significant reduction in vertical transmission (one [4%] of 26 mothers treated with zidovudine vs 12 [29%] of 42 mothers not treated with zidovudine, P = .01). There was a significant protective effect of zidovudine treatment despite lower mean absolute CD4 cell counts (0.37 x 10(9)/L) in the 24 zidovudine-treated nontransmitters and in the nine non-zidovudine-treated transmitters (0.37 x 10(9)/L) than in the 24 non-zidovudine-treated nontransmitters (0.62 x 10(9)/L) (P = .008). CONCLUSION: Maternal-fetal HIV-1 transmission is multifactorial, with increased risk associated both with ICD p24 antigenemia at term and with intrapartum events that increase fetal exposure to maternal blood. Zidovudine therapy given during pregnancy and/or labor and delivery was associated with a significant reduction in vertical transmission. These data suggest that the beneficial effects of zidovudine therapy in reducing maternal-fetal HIV-1 transmission recently found in protocol 076 of the placebo-controlled Acquired Immunodeficiency Syndrome Clinical Trials Group Study may extend to women with lower CD4 cell counts and suggest that prolonged treatment of infants may not be necessary.

Adult↗