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Biomedical subjects

J M Felser

Publications and source records attributed to J M Felser.

16 recordsLinked to original sources
PubMed1994

Clinical use of hematopoietic growth factors for control of infections after high-dose chemotherapy.

Hematopoietic growth factors are being used to accelerate the recovery of myelopoiesis following high-dose chemotherapy in cancer patients. G-CSF and GM-CSF reduce the duration of neutropenia following chemotherapy. Rapid restoration of neutrophils has been associated with reduced incidence of neutropenic fever and documented infections and fewer days of intravenous antibiotics and hospitalization. Recent studies suggest that combinations of cytokines may further expand the hematopoietic cell populations, which may be particularly useful following myeloablative chemotherapy, when thrombocytopenia may be a dose-limiting toxicity. For example, IL-3, which stimulates early progenitor cells, has definite but inconsistent effects on increasing neutrophil and platelet counts. However, in combination with later-acting cytokines (e.g., GM-CSF and IL-6), recovery from both thrombocytopenia and neutropenia is accelerated. As dose escalation of chemotherapy becomes more widely practiced, the role of cytokine combinations will become increasingly important.

Antineoplastic Agents↗
PubMed1994

Evaluation of granulocyte-macrophage colony-stimulating factor for treatment of pancytopenia in children with fanconi anemia.

Fanconi anemia is a congenital syndrome characterized by multiple specific physical anomalies, progressive marrow failure, and a predisposition to acute leukemia. We studied the toxicity and efficacy of daily subcutaneous administration of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients with Fanconi anemia and pancytopenia. The toxicity of GM-CSF at the doses and schedule used was minimal. Six of seven patients entered had an increase in the neutrophil count of 7- to 25-fold, which was maintained during the course of study. Despite increases in the reticulocyte count, increases in hemoglobin concentration were rare. No improvement in platelet count was evident in any patient. No patient has evidence of leukemia after up to 19 months of continuous GM-CSF exposure, and all five surviving patients remain responsive to treatment. Although the optimal dose, schedule, and choice of cytokine for patients with marrow failure and Fanconi anemia are not established by this preliminary study, the data indicate that (1) GM-CSF may be able to palliate at least the neutropenia and potentially the neutropenic complications of the disease, (2) this effect can be sustained for more than 1 year, and (3) rapid evolution of acute leukemia is unlikely to be a frequent outcome of such treatment. The clinical impact of GM-CSF or other cytokines in patients with Fanconi anemia and pancytopenia remains to be established by further studies.

Adolescent↗
PubMed1989

A syncytia assay for human immunodeficiency virus type I (HIV-I) envelope protein and its use in studying HIV-I mutations.

We describe a syncytia assay that utilizes a noninfectious plasmid (pEVd1443) derived from human immunodeficiency virus type I (HIV-I). This plasmid carries a large deletion of gag-pol sequences but expresses HIV-I envelope proteins and induces syncytia following transfection into HeLa-CD4 cells. This plasmid was used to study the effects of mutations in the gp 120 and gp41 portions of the envelope gene of HIV-I.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1988

Acyclovir suppression of frequently recurring genital herpes. Efficacy and diminishing need during successive years of treatment.

Forty-seven patients with frequently recurring genital herpes participated in one or more of five sequential trials of oral suppressive therapy with 200 mg of acyclovir three times daily from four to 12 months' duration. The prolonged use of acyclovir was extremely well tolerated, and treatment efficacy was sustained through successive studies. Recurrences in eight patients with repeated treatment "failures" were more effectively suppressed with higher doses of acyclovir. All patients experienced recurrent infections after the treatments were completed; however, the mean time to recurrence following each treatment period became progressively longer, and resumption of suppressive therapy was no longer warranted for ten patients. These data indicate the efficacy and safety of chronic suppressive therapy with acyclovir and the value of interrupting prolonged treatment to assess its further need.

Acyclovir↗
PubMed1988

Cell lines containing varicella-zoster virus open reading frame 62 and expressing the "IE" 175 protein complement ICP4 mutants of herpes simplex virus type 1.

Vero cells were cotransfected with pSV2neo and a recombinant plasmid containing the varicella-zoster virus (VZV) open reading frame 62 (ORF62). Three neomycin-resistant cell lines were isolated and shown to complement two different ICP4 mutants (tsB21 and d120) of herpes simplex virus (HSV) type 1 (HSV-1). VZV-specific RNA could not be detected in these cell lines, but following infection with tsB21, a 4.3-kilobase VZV transcript was detected. This RNA increased in quantity when cells were infected in the presence of cycloheximide. A VZV-specific protein of 175 kilodaltons was detected in extracts of all three cell lines following infection with wild-type HSV-1 but not in uninfected cells. That VZV RNA and protein were detected only in HSV-1 infected cells suggests that a component of the HSV virion activates the expression of VZV ORF62. The increase in RNA expression seen in the presence of cycloheximide indicates that the protein encoded by VZV ORF62, "IE"175, may be autoregulatory. These data provide further evidence that VZV "IE"175 is the functional analog of the HSV ICP4.

Animals↗
PubMed1988

NIH conference. Varicella-zoster virus infections. Biology, natural history, treatment, and prevention.

During the last 10 years, there have been major advances in the understanding of varicella-zoster virus and the diseases it causes. The molecular biology of the virus is being unraveled with the aid of new molecular technologies. Varicella, usually a benign manifestation of primary infection, and zoster, a result of reactivation of latent virus, can cause considerable morbidity in patients with immune impairment. Antiviral drugs, especially acyclovir, ameliorate severe infections but still have little role in the treatment of most normal patients with varicella or zoster. Varicella can be prevented when necessary by patient isolation and passive prophylaxis with varicella-zoster immune globulin. An experimental live vaccine also prevents varicella, but problems regarding its virulence for immunosuppressed patients and the durability of the protective response are still being addressed.

Chickenpox↗
PubMed1987

Varicella-zoster virus complements herpes simplex virus type 1 temperature-sensitive mutants.

Varicella-zoster virus (VZV) can complement temperature-sensitive mutants of herpes simplex virus. Of seven mutants tested, two, carrying mutations in the immediate-early ICP4 and ICP27 proteins, were complemented. This complementation was not seen in coinfections with adenovirus type 5 or cytomegalovirus. Following transfection into CV-1 cells, a DNA fragment containing the VZV short repeat sequence complemented the ICP4 mutant. These data demonstrate a functional relationship between VZV and herpes simplex virus and have allowed localization of a putative VZV immediate-early gene.

Cell Line↗
PubMed1986

Mapping of the varicella zoster virus deoxypyrimidine kinase gene and preliminary identification of its transcript.

The varicella-zoster virus (VZV) deoxypyrimidine kinase (dPK) gene was mapped by transfection of cloned viral DNA fragments into thymidine kinase-deficient mouse L (LTK-) cells and subsequent biochemical transformation of these cells to the LTK+ phenotype. Such transforming activity was limited to the BamHI-H and EcoRI-D fragments of the VZV genome, which overlap by 2.2 kb between map units 0.50 and 0.52. Biochemically transformed cells were shown to contain a high copy number of viral DNA sequences that had integrated into the cellular DNA. Extracts of these cells showed a higher level of dPK activity than did extracts of parental LTK- cells. With the use of Northern hybridization analysis of transformed and VZV-infected cell RNAs, it was possible to tentatively assign a 1.8-kb transcript to the VZV dPK.

Animals↗
PubMed1986

Double-blind comparison of weekend and daily regimens of oral acyclovir for suppression of recurrent genital herpes.

The potential utility of intermittent regimens of oral acyclovir for suppression of recurrent genital herpes depends on how long the suppressive effect of the drug persists during pauses in treatment. To study this question, we admitted 38 patients in a double-blind controlled trial comparing the results of daily acyclovir treatment (200 mg t.i.d.) with treatment on weekend days only (400 mg t.i.d. on Saturday and Sunday) for suppression of recurrent genital herpes. Of the 35 patients completing the study, significantly more failures occurred in the weekend group (13/17) than in the daily group (3/18, P less than 0.001). Failures on the weekend regimen were more frequent as the week progressed (P = 0.005). The findings suggest a short-term persistence of suppression by acyclovir and hence that intermittent regimens with more closely spaced periods of treatment may be more effective than the regimen we studied. Most virus isolates studied, including all of those isolated from the patients during treatment, were sensitive to acyclovir.

Acyclovir↗
PubMed1983

Infectious diseases and aging: immunologic perspectives.

Four theories of aging provide a basis for understanding both the aging process and the primary alterations in host defenses that may occur with age. The immunologic theory of aging may be especially important in this regard, since immunologic defects may be responsible for many manifestations of aging, and a decline in immune function may also underlie the increased susceptibility of the aged to infection. However, multiple factors are probably responsible for the aging process and for changes in host defenses. Although several studies attempting to enhance the immune response of elderly persons and perhaps extend lifespan are in progress, no factor at present appears to be as important in this regard as three underutilized immunizations for influenza, pneumococcal infection, and tetanus.

Aged↗
PubMed1977

An osteosarcoma cell and matrix retained morphogen for normal bone formation.

Histophysiology, ultrastructure, chemical analyses of transplants and implants of Dunn and Ridgway mouse osteosarcomas demonstrate that tumorigenesis is a manifestation of deranged morphogenesis in developing mesenchymal cell populations. The end product of development is defective, incompletely calcified, disorganized bone without any inclusions of bone marrow tissue. When Dunn osteosarcoma is freeze-dried and then implanted, the tumor is resorbed and replaced by deposits of normal cartilage, bone, and bone marrow. Freeze-dried Ridgway osteosarcoma is replaced only by a fibrous connective tissue scar. Disaggregated Dunn tumor osteoblasts synthesize a trypsin-labile collagenase-resistant cell surface localized bone morphogen. Tumor matrix stroma, prepared by sequential chemical extraction of soluble non-collagenous proteins also contains significant quantities of the same bone morphogen. Tumor tissue pulverized to particle size as small as 44 micrometer3 transmitted bone morphogen more rapidly than intact tumor tissue. The total tumor cell and stroma mediated bone morphogen produces three times more normal bone than normal cortical bone matrix. Our working hypothesis is that a normal bone morphogenetic polypeptide (BMP) is synthesized by Dunn osteosarcoma cells and retained by the tumor matrix stroma. Neither the mechanism of transmission nor the mesenchymal cell receptor sites of BMP are known.

Alkaline Phosphatase↗
PubMedDate not supplied

Effect of oral acyclovir treatment on symptomatic and asymptomatic virus shedding in recurrent genital herpes.

Twenty-six men and women with recurrent genital herpes maintained diaries of their symptoms and signs of infection and submitted 6,515 self-collected cultures during a one-year study of acyclovir therapy. As compared with periods before or after treatment, the mean rates of experiencing symptoms or lesions, and of shedding virus were significantly lower during treatment. Acyclovir treatment reduced the rate of symptomatic shedding from 95 positive cultures to six per 1,000 cultures, but the rate of asymptomatic shedding remained relatively constant, averaging eight per 1,000 cultures. Among the isolates of herpes simplex virus studied, there was no differences in sensitivity to acyclovir between strains recovered on or off therapy or during symptomatic or asymptomatic recurrences. The endonuclease cleavage profiles of asymptomatically shed viruses were essentially the same as those of the symptomatically shed viruses from the same individual. Chronic acyclovir therapy significantly reduced the symptoms and signs of recurrent genital herpes but did not eliminate virus shedding, nor, therefore, the possibility of disease transmission.

Acyclovir↗