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Dive into the research topics where George W. Santos is active.

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Featured researches published by George W. Santos.


The New England Journal of Medicine | 1983

Marrow Transplantation for Acute Nonlymphocytic Leukemia after Treatment with Busulfan and Cyclophosphamide

George W. Santos; Peter J. Tutschka; Ron Brookmeyer; Rein Saral; William E. Beschorner; Wilma B. Bias; Hayden G. Braine; William H. Burns; Gerald J. Elfenbein; Herbert Kaizer; David Mellits; Lyle L. Sensenbrenner; Robert K. Stuart; Andrew M. Yeager

Fifty-one patients with acute nonlymphocytic leukemia (16 with end-stage disease, 17 in second or third remission or in early relapse, and 18 in first remission) were given infusions of HLA-identical sibling marrow after cytoreduction with high doses of busulfan and cyclophosphamide. Actuarial two-year survival rates were 0 per cent, 29 per cent, and 44 per cent, respectively. Twelve patients are still alive and in remission after 327 to 1488 days, with 10 surviving beyond two years. Acute graft-versus-host disease and viral pneumonia were the major causes of death. Leukemic cells failed to clear in one patient with end-stage disease, and a relapse with meningeal leukemia occurred in another. Only one other relapse was seen--in a patient given a transplant during a third remission. Survival was favorably affected by younger age and transplantation during first remission. We conclude that high-dose chemotherapy with busulfan and cyclophosphamide, followed by allogeneic-marrow transplantation, can produce long-term remission of acute leukemia. Chemotherapy with high-dose busulfan and cyclophosphamide before transplantation provides an effective alternative to cyclophosphamide and total-body irradiation before transplantation for the treatment of acute nonlymphocytic leukemia.


Transplantation | 1987

VENOOCCLUSIVE DISEASE OF THE LIVER FOLLOWING BONE MARROW TRANSPLANTATION

Richard J. Jones; Kamthorn S. K. Lee; William E. Beschorner; Victor Vogel; Louise B. Grochow; Hayden G. Braine; Georgia B. Vogelsang; Lyle L. Sensenbrenner; George W. Santos; Rein Saral

Review of 235 consecutive patients undergoing bone marrow transplantation was performed in order to define the clinical syndrome of venoocclusive disease of the liver (VOD) in these patients. Analysis of all patients with histologically proven VOD revealed a consistent clinical syndrome of liver dysfunction occurring within the first 3 weeks after marrow infusion. This was characterized by hyperbilirubinemia peaking at greater than or equal to 2 mg/dl with at least 2 of 3 other findings: hepatomegaly, ascites, and 5% or greater weight gain. VOD developed in 22% (52 of 235). A persistently elevated aspartate aminotransferase (SGOT) prior to transplant was associated with an increased risk of developing VOD by multivariate analysis (P = 0.0003), and acute leukemia in first remission was associated with a decreased risk (P = 0.02). Neither the preparative regimen (busulfan and cyclophosphamide versus cyclophosphamide and total body irradiation) nor the type of graft (allogeneic versus autologous) influenced the occurrence. Twenty-four of these 52 patients (47%) died with VOD (10% of the entire group). This makes VOD the third leading cause of death in our allogeneic graft recipients, and the second leading cause in our patients receiving autologous transplants. VOD is a common complication of bone marrow transplantation and has a specific clinical presentation, which usually allows diagnosis without the need of liver biopsy.


The New England Journal of Medicine | 1982

Cytotoxic T Cells in Cytomegalovirus Infection: HLA-Restricted T-Lymphocyte and Non-T-Lymphocyte Cytotoxic Responses Correlate with Recovery from Cytomegalovirus Infection in Bone-Marrow-Transplant Recipients

Gerald V. Quinnan; Nigar Kirmani; Alain H. Rook; Jody Manischewitz; Lozannie Jackson; Gail Moreschi; George W. Santos; Rein Saral; William H. Burns

We studied 58 recipients of bone-marrow transplants to evaluate immune responses to cytomegalovirus infection. Such infection developed in 43 patients; it was fatal in 12, nonfatal in 23, and present at death from other causes in eight. All patients had low or absent cytomegalovirus-specific cytotoxic lymphocyte activity before the onset of infection. Cytomegalovirus-specific cytotoxic responses developed in all survivors, whereas only two patients with fatal infection had even low-level cytomegalovirus-specific cytotoxic responses. Natural and antibody-dependent killer-cell activities were depressed both before and during infection in patients with fatal infections, but not in those who survived. The outcome of the infection did not correlate with the nature of the underlying disease, the type of transplant received, the pretransplantation cytomegalovirus-antibody status, or lymphocyte-proliferation responses to cytomegalovirus antigens or concanavalin A. The correlation between effective virus-specific cytotoxic response and recovery from infection indicates that these effector cells probably mediate recovery from cytomegalovirus infection.


The New England Journal of Medicine | 1981

Acyclovir prophylaxis of herpes-simplex-virus infections. A randomized, double-blind, controlled trial in bone-marrow-transplant recipients.

Rein Saral; William H. Burns; Oscar L. Laskin; George W. Santos; Paul S. Lietman

We conducted a double-blind, placebo-controlled study of acyclovir prophylaxis against infection with herpes simplex virus (HSV) in 20 seropositive recipients of bone-marrow transplants. Acyclovir or placebo was administered for 18 days, starting three days before transplantation. Culture-positive HSV lesions developed during the study in seven of the 10 patients who received placebo. In contrast, no such lesions appeared in the 10 patients who received acyclovir (P congruent to 0.003). None of the patients had evidence of drug toxicity. Five of the patients treated with acyclovir had mild culture-positive HSV infections after cessation of the drug, and two additional patients shed virus without having lesions. Acyclovir appears to be a potent inhibitor of HSV replication. Although acyclovir does no appear to eradicate latent infection, it can provide effective prophylaxis against reactivated infections.


The New England Journal of Medicine | 1986

Autologous Bone Marrow Transplantation in Patients with Acute Nonlymphocytic Leukemia, Using ex Vivo Marrow Treatment with 4-Hydroperoxycyclophosphamide

Andrew M. Yeager; Herbert Kaizer; George W. Santos; Rein Saral; O. M. Colvin; Robert K. Stuart; Hayden G. Braine; Philip J. Burke; Richard F. Ambinder; William H. Burns

We studied 25 patients with acute nonlymphocytic leukemia in second remission (20 patients) or third remission (5 patients) in whom autologous bone marrow transplantation was performed with use of marrow incubated ex vivo with the alkylating agent 4-hydroperoxycyclophosphamide. Patients received intensive cytoreductive therapy with busulfan and cyclophosphamide or cyclophosphamide and total body irradiation, followed by an infusion of marrow that had been collected in remission, treated with 4-hydroperoxycyclophosphamide, and cryopreserved. Four patients died from bacterial or fungal sepsis within the first month after transplantation, and one patient with persistent marrow hypoplasia died from gram-negative sepsis 155 days after infusion with autologous marrow. In the remaining patients, peripheral-blood levels of neutrophils in excess of 0.5 X 10(9) per liter and platelet counts over 50 X 10(9) per liter were attained at median intervals of 29 and 57 days after transplantation, respectively. Nine patients had leukemic relapses at 73 to 316 days (median, 182 days) after infusion of autologous marrow, for an actuarial relapse rate of 46 percent. Eleven patients (eight in second remission and three in third) remained in remission at a median of more than 400 days (range, greater than 230 to greater than 1653 days) after transplantation. The observed disease-free survival after transplantation with autologous marrow treated with 4-hydroperoxycyclophosphamide compares favorably with the results of syngeneic or allogeneic transplantation in similar groups of patients.


Cancer Chemotherapy and Pharmacology | 1989

Pharmacokinetics of busulfan: correlation with veno-occlusive disease in patients undergoing bone marrow transplantation

Louise B. Grochow; Richard J. Jones; Robert B. Brundrett; Hayden G. Braine; Tian Ling Chen; Rein Saral; George W. Santos; O. Michael Colvin

SummaryBusulfan is an alkylating agent that is widely used in preparative regimens for bone marrow transplantation (BMT). We developed a high-performance liquid chromatographic (HPLC) assay for the determination of plasma busulfan concentrations in 30 patients who received oral doses of 1 mg/kg. Concentrations were fit by a one-compartment pharmacokinetic model with first-order absorption. The pattern of absorption and elimination varied widely between patients, with peak concentrations ranging from 1.2 to 10.4 μmol/l (mean, 4.25±2.49). The climination half-life ranged from 58 to 433 min (harmonic mean, 140 min). The AUC contributed by a single oral dose ranged from 606 to 5,144 μmol-min/l (mean, 2,012±1,223). Patients were evaluated for the development of veno-occlusive disease (VOD), a treatment complication that occurs in 20% of patients undergoing BMT and causes 10% of transplantation-related deaths. All six patients who developed VOD had an AUC greater than the mean, and five of them had an AUC that was >1 SD above the mean. The occurrence of VOD was highly correlated with an increased AUC (>1 SD above the mean) (X2=18;P<0.0001). Using multivariate logistic regression, no other statistically significant pharmacokinetic predictor of VOD was found. The tenfold variability in the busulfan AUC and the statistical association of increased AUC with the development of VOD suggest a possible role for therapeutic monitoring in this setting.


The New England Journal of Medicine | 1986

Association of BK Viruria with Hemorrhagic Cystitis in Recipients of Bone Marrow Transplants

Ray R. Arthur; Keerti V. Shah; Stephen J. Baust; George W. Santos; Rein Saral

Fifty-three recipients of bone marrow transplants were monitored prospectively for urinary excretion of human polyomaviruses by enzyme-linked immunosorbent assays of urinary supernatants and DNA hybridization assays of urinary cells. Excretion of BK virus was demonstrated in 47 percent of the transplant recipients and was the result of the reactivation of latent virus. Hemorrhagic cystitis of long duration (greater than or equal to 7 days) was associated with BK viruria. The disease occurred four times more frequently in patients who excreted BK virus than in those who did not, and the virus was identified in 55 percent of the urine specimens during episodes of cystitis as compared with 8 to 11 percent of the specimens during cystitis-free periods. BK viruria often preceded or coincided with the onset of the disease. Among 19 patients with BK viruria lasting seven days or longer, hemorrhagic cystitis occurred in 15. Occurrence of the disease was related to the source of marrow. The disease occurred in 50 percent of 38 recipients of allogeneic marrow and in 7 percent of 15 recipients of syngeneic or autologous marrow. Among recipients of allogeneic marrow, the disease was observed in 71 percent of the 21 patients excreting BK virus and in 24 percent of the 17 not excreting the virus. An association of BK virus with hemorrhagic cystitis was demonstrated in 16 of the 18 cases of the disease that were adequately characterized. We conclude that reactivation of BK virus may account for a substantial proportion of late-onset, long-lasting hemorrhagic cystitis in recipients of bone marrow transplants.


The New England Journal of Medicine | 1982

Infectious Gastroenteritis in Bone-Marrow-Transplant Recipients

Robert H. Yolken; Catherine A. Bishop; Timothy R. Townsend; Elizabeth A. Bolyard; John A. Bartlett; George W. Santos; Rein Saral

We prospectively evaluated infections with several gastrointestinal pathogens in patients undergoing bone-marrow transplantation, in an attempt to correlate infection with morbidity and mortality. Thirty-one of 78 patients (40 per cent) were infected with one or more of the following enteric pathogens during the study: adenovirus (12 infections), rotavirus (nine), coxsackievirus (four), or Clostridium difficile (12). Several patients were infected with more than one pathogen. Infection correlated with the occurrence of diarrhea and abdominal cramps. The mortality rate among the infected patients was 55 per cent--significantly higher than the rate (13 per cent) among the noninfected patients (P less than 0.001). This study indicates that enteric pathogens that often cause mild diarrhea in normal populations can cause serious infections in marrow-transplant recipients. Measures aimed at preventing or treating such infections might reduce the morbidity and mortality associated with marrow transplantation.


Clinical Immunology and Immunopathology | 1973

The graft versus host reaction in man after bone marrow transplantation: Pathology, pathogenesis, clinical features, and implication

Richard E. Slavin; George W. Santos

Abstract The lesions of the graft versus host reaction are described in eight patients receiving bone marrow transplants and cyclophosphamide cytoreductive therapy. The pathologic alterations are divided into two categories, the lymphoid response and the aggressor lymphocyte destructive lesions. The lymphoid response occurs in lymph nodes and the splenic white pulp previously depleted by cyclophosphamide therapy. It consists of a transient phase of lymphoblastic transformation and proliferation followed by rapidly developing lymphoid depletion during which a population shift to small lymphocytes occurs. This culminates in severe lymphoid atrophy which is eventually followed by early normal lymphoid repopulation, taking place especially in B-lymphocyte zones. Presumably the lymphoid response chiefly involves donor cells. In the aggressor lymphocyte destructive lesions squamous epithelia principally that of the skin, tongue, and esophagus, show intercellular edema of squamous epithelium, liquefaction changes, and coagulative necrosis with acantholysis and lacunae formation in the lower squamous epithelial cells as well as pilosebaceous units. This may be followed by suprabasal bullae, sloughing of the upper epidermis, and eventually epidermal atrophy. Intestinal lesions consist of necrosis of crypt epithelium leading to glandular depopulation. The liver shows focal coagulation necrosis lf hepatocytes and Kupffer cells, primarily but not exclusively occurring adjacent to the portal triads, disruption of the limiting plate and canals of Hering and Kupffer cell hyperplasia. Lymphoid organs and bone marrow exhibit discrete necrosis of individual cells. The GVHR apparently insured total riddance of leukemia in our patients and the total replacement of host lymphohematopoietic system by donor cells. The clinical triad of dermatitis, diarrhea, and liver dysfunction are due initially to the described pathologic alterations but may later on be accounted for by the development of secondary infections, primarily viral, leading to the syndrome of graft versus host disease. This mimicks the GVHR.


Ophthalmology | 1983

Ocular Manifestations of Graft-vs-Host Disease

Rudolph M. Franklin; Kenneth R. Kenyon; Peter J. Tutschka; Rein Saral; W. Richard Green; George W. Santos

In patients who have graft-vs-host disease (GVHD) after bone marrow transplantation, ocular involvement occurs in approximately 60% of cases. Among 13 such GVHD patients, the most frequent ocular manifestations included keratoconjunctivitis sicca, cicatricial lagophthalmos, and sterile conjunctivitis and uveitis. The severe ocular complications of persistent corneal epithelial defects and both noninfected and infected stromal ulceration were related to the concomitant dry-eye condition and could be managed by conventional therapy including topical lubricants and antibiotics, punctal occlusion, bandage soft contact lenses, tarsorrhaphy, tissue adhesive, conjunctival flap, and conjunctival homograft. Postmortem and surgical tissues from four patients revealed conjunctival and corneal epithelial thinning and keratinization, lacrimal inspissation without inflammatory infiltration, and diffuse choroiditis. Keratoconjunctivitis sicca in GVHD patients might be a combined result of drug toxicity effects and GVHD. The frequent and potentially severe ocular problems in these patients suggest that close ophthalmic monitoring is mandatory in bone marrow transplant recipients.

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Rein Saral

Johns Hopkins University

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Allan D. Hess

Johns Hopkins University

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William H. Burns

Medical College of Wisconsin

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Andrew M. Yeager

Johns Hopkins University School of Medicine

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Herbert Kaizer

Johns Hopkins University

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