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Biomedical subjects

R J Whitley

Publications and source records attributed to R J Whitley.

At least 19 recordsLinked to original sources
PubMed2000

Engineered herpes simplex virus expressing IL-12 in the treatment of experimental murine brain tumors.

Genetically engineered, neuroattenuated herpes simplex viruses (HSVs) expressing various cytokines can improve survival when used in the treatment of experimental brain tumors. These attenuated viruses have both copies of gamma(1)34.5 deleted. Recently, we demonstrated increased survival of C57BL/6 mice bearing syngeneic GL-261 gliomas when treated with an engineered HSV expressing IL-4, as compared with treatment with the parent construct (gamma(1)34. 5(-)) alone or with a virus expressing IL-10. Herein, we report construction of a conditionally replication-competent mutant expressing both subunits of mIL-12 (M002) and its evaluation in a syngeneic neuroblastoma murine model. IL-12 induces a helper T cell subset type 1 response, which may induce more durable antitumor effects. In vitro studies showed that, when infected with M002, both Vero cells and murine Neuro-2a neuroblastoma cells produced physiologically relevant levels of IL-12 heterodimers, as determined by ELISA. M002 was cytotoxic for Neuro-2a cells and human glioma cell lines U251MG and D54MG. Neurotoxicity studies, as defined by plaque-forming units/LD(50), performed in HSV-1-sensitive A/J strain mice found that M002 was not toxic even at high doses. When evaluated in an intracranial syngeneic neuroblastoma murine model, median survival of M002-treated animals was significantly longer than the median survival of animals treated with R3659, the parent gamma(1)34.5(-) mutant lacking any cytokine gene insert. Immunohistochemical analysis of M002-treated tumors identified a pronounced influx of CD4(+) T cells and macrophages as well as CD8(+) cells when compared with an analysis of R3659-treated tumors. We conclude that M002 produced a survival benefit via oncolytic effects combined with immunologic effects meditated by helper T cells of subset type 1.

Animals↗
PubMed1999

Replication-competent, nonneuroinvasive genetically engineered herpes virus is highly effective in the treatment of therapy-resistant experimental human tumors.

A genetically engineered, nonneurotropic herpes simplex virus (R7020) with a proven safety profile in both animals and humans was found effective in the treatment of large xenotransplanted tumors arising from a radiation- and chemotherapy-resistant human epidermoid carcinoma and a hormone-refractory prostate adenocarcinoma. R7020 replicated to high titer and caused rapid regression of the human tumor xenografts. Tumor destruction was accelerated in animals given both R7020 and fractionated ionizing radiation. Tumors arising from cells surviving one treatment with R7020 were fully susceptible to a second dose of virus. We conclude R7020 is an effective antitumor agent for non-central nervous system tumor xenografts with an excellent safety profile.

Adenocarcinoma↗
PubMed1999

Therapeutic approaches to the management of herpes zoster.

The past several years have provided exciting advances in the management of herpes zoster in the normal host. In spite of these advances, a significant portion of zoster patients still have persistent complications from this disease. Persistent pain is the most debilitating sequela and it occurs in at least 15% of individuals over 50 years of age. Future research efforts must embrace alternative approaches for pain control.

2-Aminopurine↗
PubMed1999

Use of the ganciclovir implant for the treatment of cytomegalovirus retinitis in the era of potent antiretroviral therapy: recommendations of the International AIDS Society-USA panel.

PURPOSE: To describe the risks, benefits, and recommended use of the ganciclovir implant for the treatment of human immunodeficiency virus-related cytomegalovirus (CMV) retinitis in the era of potent antiretroviral therapy. METHODS: A panel of physicians with expertise in the use of the ganciclovir implant and in the management of CMV retinitis was convened by the International AIDS Society-USA. The panel reviewed and discussed available data, and developed recommendations for the use of the ganciclovir implant, the surgical technique, and related management issues. Recommendations were rated according to the strength and quality of the supporting evidence. RESULTS: The effect of potent antiretroviral therapy on the immunologic status of patients with human immunodeficiency virus disease has changed the manifestation and course of CMV retinitis in many patients. The clinical management of CMV retinitis and the role of the ganciclovir implant are thus changing. Factors in the decision to choose the ganciclovir implant include the patient's potential for immunologic improvement, location and severity of CMV retinitis, and the risks and costs associated with implantation and concomitant oral ganciclovir therapy. CONCLUSIONS: The ganciclovir implant is safe and effective for the treatment of CMV retinitis. The indications for its use should be modified to account for increased patient survival and the potential for CMV retinitis to be controlled by effective antiretroviral therapy. Optimal use of the ganciclovir implant and discontinuation of therapy in selected patients with improvement in immunity may result in better long-term visual outcomes.

AIDS-Related Opportunistic Infections↗
PubMed1999

Effect of recombinant human interferon alpha B/D (rHu-IFN-alpha B/D) in combination with acyclovir in experimental HSV-1 encephalitis.

The efficacy of recombinant human interferon alpha B/D in experimental HSV-1 encephalitis was investigated in the murine system. Recombinant Hu-IFN-alpha B/D significantly reduced the mortality in a mouse encephalitis model (about 30%, P = 0.021), whereas natural mouse interferon was inactive. Combination of acyclovir with Hu-IFN-alpha B/D had an additive effect.

Acyclovir↗
PubMed1999

A mixed model for factors predictive of pain in AIDS patients with herpes zoster.

A unifying model of herpes zoster pain presents considerable analytical challenges due to the requirement for prospective data collection and the varying rates of pain resolution reported by individual patients. Demographic, clinical, and quality-of-life measures were collected on 166 human immunodeficiency virus (HIV)-infected patients enrolled in a randomized, controlled trial of antiviral therapy of herpes zoster comparing acyclovir with sorivudine. A "mixed model" was used to assess factors predictive of pain severity, activity impairment, and sleep interruption. The average rate of change in acute pain was -0.04 unit pain per day for the first month. Chronic pain decreased -0.12 per month for months 1-12. Acute pain severity was positively correlated with number of new skin vesicles, analgesic use, and baseline pain, and negatively related to percentage of lesion healing and crusting. Postherpetic neuralgia was correlated with baseline pain, pain at 1 month, and duration of lesions. Treatment group, gender, race, and CD4 count were not related to change in pain severity. These analyses verify the significance of baseline pain as a significant predictor of pain resolution and average pain severity as a predictor of return to normal daily activities and sleep. The severity of acute pain at presentation and at 1 month are significant predictors of chronic pain.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Herpes zoster: risk categories for persistent pain.

Acute neuritis and persistent pain are the most significant clinical manifestations of herpes zoster and are end points for clinical trials therapy. In an acyclovir and prednisone study, patients were categorized according to pain severity and number of lesions at presentation. Risk categories were defined according to the magnitude of risk ratios (RRs) and a comparison of Kaplan-Meier survival estimates. For acute neuritis and zoster-associated pain, RRs defined rate of resolution. Patients who presented with severe or incapacitating pain and a large number of lesions were less likely to achieve resolution of both acute neuritis and zoster-associated pain (RR, 18.0; 95% confidence interval [CI], 6. 6-48.6, and RR, 5.3; 95% CI, 4.2-17.2, respectively). These analyses identify the subgroups of patients for whom aggressive interventions are most strongly indicated.

Activities of Daily Living↗
PubMed1999

Clinical significance of enteroviruses in serious summer febrile illnesses of children.

BACKGROUND: Enteroviruses are common causes of aseptic meningitis and nonspecific febrile illnesses in young children. During the summer-fall months, enterovirus-infected children are frequently evaluated in emergency room settings to rule out bacterial sepsis and/or meningitis. OBJECTIVES: We sought to determine the clinical significance of enterovirus infections in children evaluated for serious febrile illnesses in pediatric emergency rooms during the summer-fall season. METHODS: Children admitted to emergency rooms at four university teaching hospitals during a single summer-fall season who required blood culture and/or lumbar puncture to rule out bacterial sepsis/meningitis were prospectively studied. An extensive questionnaire was administered, and specimens of cerebrospinal fluid, serum, urine and throat were tested for enteroviruses by viral culture and PCR. Patients were followed to determine the duration, management and outcome of their illnesses. RESULTS: Of 203 patients studied 173 had no apparent explanation for their illness (e.g. bacterial sepsis, bacterial urinary tract infection, etc.). Of those 173 patients 79 (46%) were infected with enteroviruses, including 33 of 47 (70%) patients with aseptic meningitis, 13 of 25 (52%) patients with nonspecific febrile episodes and 33 of 101 (33%) patients with fever and focal findings (P < 0.0001 for aseptic meningitis vs. fever and focal findings; P = 0.0001 for aseptic meningitis vs. combined nonspecific febrile episodes and fever/focal patients). Among 119 hospitalized patients 65 (55%) were enterovirus-infected. Children < or =90 days of age were more likely to be enterovirus-infected (66 of 122; 54%) than children older than 90 days (13 of 51; 25%) (P = 0.0001). Enterovirus-infected children were more likely to be hospitalized as a result of the current emergency room visit (65 of 79 vs. 54 of 94; P = 0.0005) and were more likely to have had an additional hospitalization for the same illness (10 of 79 vs. 1 of 94; P = 0.003). Enterovirus-infected patients also had a shorter period from illness onset to presentation. Enterovirus-infected children were indistinguishable from those without enterovirus infection in their symptoms at onset, signs at presentation and total duration of illness (>7 days in both groups). Enterovirus-infected children were almost all treated with antibiotics (78 of 79; 99%), with 74 of 79 (94%) receiving parenteral antibiotics for a mean of 3.6 days. CONCLUSIONS: During the summer-fall months, 39% (79 of 203) of children for whom blood cultures and/or lumbar punctures were performed for suspected bacterial infection had enterovirus infection identified as the only explanation for their illness. Of those patients with no alternative diagnosis, enterovirus infection was confirmed in 46% (79 of 179). The majority of those patients requiring hospitalization were infected with enteroviruses. The use of PCR increases the number of children for whom a specific etiology of illness can be determined and may in the future reduce the hospitalization and use of unnecessary antibiotics in patients with enterovirus infections.

Emergency Service, Hospital↗
PubMed1999

Ionizing radiation improves survival in mice bearing intracranial high-grade gliomas injected with genetically modified herpes simplex virus.

Malignant gliomas remain incurable with current interventions. Encouraging investigational approaches include the use of genetically modified herpes simplex-1 (HSV-1) viruses as direct cytotoxic agents. Combining attenuated HSV-1 with standard therapy, human U-87 malignant glioma xenografts grown in the hind limb or intracranially in athymic nude mice were exposed to ionizing radiation, inoculated with genetically modified HSV R3616, or received both virus and radiation. The combination of virus with fractionated ionizing radiation suggests a synergistic action and results in reduced tumor volumes and longer survivals when compared with treatment with either modality alone.

Animals↗
PubMed1998

Guidelines for the treatment of cytomegalovirus diseases in patients with AIDS in the era of potent antiretroviral therapy: recommendations of an international panel. International AIDS Society-USA.

OBJECTIVE: To provide recommendations for the treatment of acquired immunodeficiency syndrome-related cytomegalovirus (CMV) end-organ diseases, including retinitis, colitis, pneumonitis, and neurologic diseases. PARTICIPANTS: A 17-member panel of physicians with expertise in clinical and virological research and inpatient care in the field of CMV diseases. EVIDENCE: Available clinical and virological study results. Recommendations are rated according to the quality and strength of available evidence. Recommendations were limited to the treatment of CMV diseases; prophylaxis recommendations are not included. PROCESS: The panel was convened in February 1997 and met regularly through November 1997. Subgroups of the panel summarized and presented available information on specific topics to the full panel; recommendations and ratings were determined by group consensus. CONCLUSIONS: Although the epidemiological features of CMV diseases are changing in the setting of potent, combination antiretroviral therapy, continued attention must be paid to CMV diseases in patients infected with the human immunodeficiency virus to prevent irreversible endorgan dysfunction. The initial and maintenance treatment of CMV retinitis must be individualized based on the characteristics of the lesions, including location and extent, specific patient factors, and characteristics of available therapies among others. Management of relapse or refractory retinitis must be likewise individualized. Ophthalmologic screening for patients at high risk for retinitis or who have a prior diagnosis of extraretinal disease is recommended. Recommendations for gastrointestinal, pulmonary, and neurologic manifestations are included.

AIDS-Related Opportunistic Infections↗
PubMed1998

Pharmacokinetics of oral valacyclovir and acyclovir in late pregnancy.

OBJECTIVE: The objective was to obtain preliminary pharmacokinetic data for acyclovir from gravid women receiving herpes simplex virus suppressive therapy with the acyclovir prodrug valacyclovir. STUDY DESIGN: In a prospective, double-blind trial, 20 women with a history of recurrent genital herpes simplex virus infection and positive herpes simplex virus 2 serologic results were randomly assigned at 36 weeks' gestation to receive oral valacyclovir (500 mg twice daily) or acyclovir (400 mg 3 times daily). Acyclovir pharmacokinetic profiles were obtained after the initial dose (36 weeks) and at steady state (38 weeks). Amniotic fluid samples were obtained during labor and simultaneous umbilical cord and maternal plasma samples were collected at delivery. Laboratory studies were performed to screen for laboratory evidence of toxicity in mothers and infants. RESULTS: Peak acyclovir plasma concentrations (mean +/- standard deviation) were higher in valacyclovir recipients than in acyclovir recipients after the initial dose (3.14 +/- 0.7 microg/mL vs 0.74 +/- 0.6 microg/mL, P < .0001) and at steady state (3.03 +/- 1.0 microg/mL vs 0.94 +/- 0.7 microg/mL, P < .001). The daily area under the curve values were higher in valacyclovir recipients than acyclovir recipients after the initial dose (17.8 +/- 3.6 h x microg/mL vs 7.71 +/- 2.5 h x microg/mL, P < .001) and at steady state (19.65 +/- 6.4 h x microg/mL versus 11.0 +/- 4.5 h x microg/mL, P = .009). There was no significant difference in drug elimination half-life or in time to peak concentration between valacyclovir and acyclovir recipients at either sampling interval. Acyclovir was concentrated in the amniotic fluid; however, there was no evidence of preferential fetal drug accumulation (mean maternal/umbilical vein plasma ratios at delivery were 1.7 for valacyclovir and 1.3 for acyclovir). Valacyclovir was well tolerated, and no significant laboratory or clinical evidence of toxicity was detected. CONCLUSION: In this phase I trial maternal valacyclovir therapy resulted in higher plasma acyclovir levels, with significantly higher peak concentrations and daily area under the curve values, than did acyclovir therapy. Additional trials are needed to further evaluate the safety and efficacy of suppressive valacyclovir therapy during late pregnancy.

Acyclovir↗
PubMed1998

Comparison of antiviral compounds against human herpesvirus 6 and 7.

Four classes of antiviral compounds were evaluated for inhibitory activity against two variants of human herpesvirus 6 (HHV-6A and -6B) and human herpesvirus 7 (HHV-7). These included: (1) a pyrophosphate analog, phosphonoformic acid (PFA); (2) beta-guanine analogs, 9-(2-hydroxyethoxymethyl)guanine (acyclovir or ACV), 9-[(1,3-dihydroxy-2-propoxy)methyl]guanine (ganciclovir or GCV) and 9-(4-hydroxy-3-hydroxy-3-hydroxymethylbutylyl)guanine (penciclovir or PCV); (3) acyclic nucleoside phosphonates, (S)-1-[(3-hydroxy-2-phosphonylmethoxy)propyl]cytosine [cidofovir or (S)-HPMPC] and its cyclic derivative (S)-cyclic-HPMPC (cHPMPC), 9-[[2-hydroxy-1-phosphonomethoxy)ethoxy]methyl]guanine (HPMEMG) and 9-[(2-phosphonylmethoxy)ethyl]-2,6-diaminopurine (PMEDAP), and the seven other related compounds; and (4) a series of benzimidazole ribonucleosides, including 2-bromo-5,6-dichloro-1-(beta-D-ribofuranosyl)benzimidazole (BDCRB). End-point inhibitory concentration (EPC) and 50% effective inhibitory concentration (EC50) values were determined by a dot-blot antigen detection method in cord blood mononuclear cells infected with HHV-6A, HHV-6B or HHV-7 at a multiplicity of infection of 0.004 CCID50/cell. (S)-HPMPC and cHPMPC had an EC50 value of approximately 0.3 microg/ml for HHV-6A, 1.2 microg/ml for HHV-6B and 3.0 microg/ml for HHV-7. These compounds were the most active of those tested against each virus. The EC50 value of GCV for HHV-6A was 0.65 microg/ml, 1.33 microg/ml for HHV-6B, and >7 microg/ml for HHV-7. The EC50 values of ACV and PCV were approximately 6-8 microg/ml for HHV-6A, 16-24 microg/ml for HHV-6B and 121-128 microg/ml for HHV-7. These drugs were the least active. The sensitivity of HHV-7 to the guanine analogs was different from HHV-6, suggesting a difference in selectivity of specific viral enzymes.

Antiviral Agents↗