Pharmacokinetics of Maribavir, a Novel Oral Anticytomegalovirus Agent, in Subjects With Varying Degrees of Renal Impairment

The effect of renal function on the pharmacokinetics of maribavir, a novel anticytomegalovirus agent, was evaluated in 12 adults with normal renal function (creatinine clearance [CrCl] >80 mL/min) and 19 adults with renal impairment classified as mild (n = 5), moderate (n = 5), or severe (n = 9), as measured by CrCl 50-80, 30-49, and <30 mL/min, respectively. After a single oral dose of maribavir 400 mg, the pharmacokinetics of maribavir, based on total and unbound plasma concentrations, showed no statistically significant difference between subjects with normal renal function and subjects with mild/moderate or severe renal impairment. Renal impairment was associated with an increase in area under the plasma concentration-time curve (AUC) values for an inactive metabolite of maribavir, VP 44469. Results were consistent with those of previous studies, which showed that very little maribavir was excreted unchanged in urine, whereas about 22% of an oral dose of maribavir is recovered in urine as VP 44469.

Effect of ketoconazole on the pharmacokinetics of maribavir in healthy adults

Maribavir, an oral antiviral drug with activity against cytomegalovirus, is currently undergoing studies to assess its efficacy and safety as cytomegalovirus prophylaxis following stem cell or solid organ transplantation. The main objective of this study was to assess the effects of oral ketoconazole, a potent inhibitor of the cytochrome P450 3A4 (CYP3A4) isoenzyme, on the pharmacokinetics of maribavir. This was an open-label crossover study with 20 healthy adults. Subjects were administered a single dose of maribavir at 400 mg. After a washout period, subjects received a single dose of ketoconazole at 400 mg followed by a single dose of maribavir. Blood samples were collected for each drug sequence, and pharmacokinetic parameters for maribavir and its principal metabolite, VP 44469, were determined. Safety was evaluated by physical examination, clinical laboratory testing, 12-lead electrocardiogram, and monitoring for adverse events. Ketoconazole moderately reduced the clearance of both maribavir and VP 44469; oral clearance values were 35% and 13% lower, respectively, for maribavir-plus-ketoconazole treatment than for maribavir alone. Based on the assumption of complete inhibition of CYP3A4 activity, CYP3A4 is responsible for 35% of the overall clearance of maribavir. Treatment was generally well tolerated. The most-common adverse event was dysgeusia (taste disturbance), reported by nine (47%) and seven (35%) subjects in the maribavir alone and maribavir-plus-ketoconazole groups, respectively. The pharmacokinetic findings, in combination with the acceptable tolerability within the maribavir and maribavir-plus-ketoconazole treatment groups, suggest that no dose adjustment of maribavir is necessary when coadministered with CYP3A4 inhibitors or substrates.

Cytoprotection by Jun kinase during nitric oxide-induced cardiac myocyte apoptosis

Nitric oxide (NO) induces apoptosis in cardiac myocytes through an oxidant-sensitive mechanism. However, additional factors appear to modulate the exact timing and rate of NO-dependent apoptosis. In this study, we investigated the role of mitogen-activated protein kinases (MAPKs) (extracellular signal-regulated kinase [ERK] 1/2, c-Jun N-terminal kinase [JNK] 1/2, and p38MAPK) in NO-mediated apoptotic signaling. The NO donor S:-nitrosoglutathione (GSNO) induced caspase-dependent apoptosis in neonatal rat cardiac myocytes, preceded by a rapid (<10-minute) and significant (approximately 50-fold) activation of JNK1/2. Activation of JNK was cGMP dependent and was inversely related to NO concentration; it was maximal at the lowest dose of GSNO (10 micromol/L) and negligible at 1 mmol/L. NO slightly increased ERK1/2 beginning at 2 hours but did not affect p38MAPK activity. Inhibitors of ERK and p38MAPK activation did not affect cell death rates. In contrast, expression of dominant-negative JNK1 or MKK4 mutants significantly increased NO-induced apoptosis at 5 hours (56.77% and 57.37%, respectively, versus control, 40.5%), whereas MEKK1, an upstream activator of JNK, sharply reduced apoptosis in a JNK-dependent manner. Adenovirus-mediated expression of dominant-negative JNK1 both eliminated the rapid activation of JNK by NO and accelerated NO-mediated apoptosis by approximately 2 hours. These data indicate that NO activates JNK as part of a cytoprotective response, concurrent with initiation of apoptotic signaling. Early, transient activation of JNK serves both to delay and to reduce the total extent of apoptosis in cardiac myocytes.

Beware of contaminating mouse cells in human xenografts from nude mice

Human tumor xenografts in nude mice are widely utilized model system for the transplantation of human surgical specimens and human established cell lines. Gene expression studies are often carried out in these model systems. With an increasing use of PCR based analyses, the extreme sensitivity of this technique poses a serious challenge with regards to the extent of contaminating host mouse cells in the human tumor xenografts. These xenografts are never free of host cell contamination. We detected mouse estrogen receptor expression in several human tumor xenografts using RT-PCR demonstrating that precaution is necessary when utilizing PCR based analyses in human tumor xenografts. A cytologically based methodology which distinguishes human versus mouse cells will be more suitable for ER expression studies using human xenograft models. Both (1) in situ hybridization using human probe and (2) immunocytochemistry using a monoclonal antibody directed against human cytokeratin have been used successfully to distinguish human cells versus host mouse cells in human xenografts in nude mice. Immunostaining of ER can then be utilized to determine the expression pattern of ER in the transplanted human cells.

Estrogen and progesterone receptors can be maintained in normal human breast epithelial cells in primary culture and after transplantation into nude mice

The estrogen and progesterone receptor expression was determined in breast epithelial cells from reduction mammoplasty specimens. Only a subset of the luminal epithelial cell population was found to be positive for these receptors. When these cells were subsequently cultured in 3-dimensional collagen gel system (in vitro model) or transplanted into nude mice (in vivo model), the cells retained their ability to express both receptors in these experimental systems. The maintenance of primary normal human breast epithelial cells expressing the estrogen and progesterone receptors in experimental systems has not been reported previously.

Musculoskeletal transplant

Allograft tissue has been used for more than two centuries in the repair of musculoskeletal injuries and defects. More than 150,000 procedures are performed each year in the United States alone, 10 times the number of organ transplants. Nurses caring for allograft recipients may be unfamiliar with where tissue comes from, how it is recovered, and the variety of its practical applications. Similar to the process of organ donation, with which many nurses have had experience, it all begins with the gift.

Adeno-associated virus vector mediated transduction of primary normal human breast epithelial cells

Cultured human breast epithelial cells from reduction mammoplasty specimens were transduced using an adeno-associated virus vector encoding the marker gene E. coli -galactosidase. Subconfluent, growing, breast epithelial cells were more easily transduced than confluent, quiescent, cells. Transduction of non-dividing confluent cells could be greatly increased by ultraviolet light-induced DNA damage or by prior exposure to the DNA synthesis inhibitor hydroxyurea. The effects of ultraviolet light and hydroxyurea on transduction were additive when these agents were applied together.

Core values in health care reform: a communitarian approach

Controlling health care costs should allow the nation to provide more health services and higher quality care to more people. The authors are concerned, however, that many of the reform efforts will unwittingly undermine the culture of care in their pursuit of savings and access. This article is a plea to maintain the core moral values and the social and institutional commitments that are essential in the delivery of care, so that the health care community is not turned into a health industry. The authors' communitarian approach aims to preserve the balance between individual rights and social responsibilities, the moral integrity of a caring society, and the unique character of mutual trust between patients and health care personnel. They advocate an orientation toward preventing disease and promoting health, an imperative of reforming the violent, reckless, and costly aspects of American society, and a moral justification for cutting administrative waste, defensive medicine, and excessive profits rather than rationing beneficial and humane health services.

Twin pregnancy: the impact of the Higgins Nutrition Intervention Program on maternal and neonatal outcomes

Perinatal outcomes were compared between 354 twins treated with the Higgins Nutrition Intervention Program and 686 untreated twins. After differing distributions of key confounding variables were adjusted for, the twins in the intervention group weighed an average of 80 g more (P less than 0.06) than the nonintervention twins; their low-birth-weight rate was 25% lower (P less than 0.05) and their very-low-birth-weight rate was almost 50% lower (P less than 0.05). Although the rate of preterm delivery was 30% lower in the intervention group (P less than 0.05), the rates of intrauterine growth retardation were similar in the two groups. Fetal mortality was slightly higher (14 vs 12 per 1000, NS), but early neonatal mortality was fivefold lower (3 vs 19 per 1000, P less than 0.06) in the intervention group. Maternal morbidity was significantly lower (P less than 0.05) in the intervention group. There was a trend towards lower infant morbidity in the intervention group. These results suggest that nutritional intervention can significantly improve twin-pregnancy outcome.

DRGs and the "negative" trauma workup

We conducted a study to assess the financial impact of the diagnostic workup and care of 136 trauma patients admitted to our institution during a six-month period who were subsequently found to have only minor injuries (Injury Severity Score less than or equal to 9, Abbreviated Injury Score less than 3). The New Jersey DRG reimbursement system, an all-payer system, failed to provide adequate financial compensation overall, as the average loss per patient (operating cost minus reimbursement) was $508. Lost potential revenue (hospital charges minus reimbursement) was even greater, averaging $1,834 per patient. We conclude that the New Jersey DRG reimbursement system, in its current form, provides inadequate reimbursement for the system, in its current form, provides inadequate reimbursement for the proper workup and treatment of trauma patients with minor injuries. Because these patients are those most likely to help "subsidize" the care of sicker patients, changes in the system are necessary to allow hospitals to continue to provide state-of-the-art trauma care and to continue to minimize the number of preventable deaths due to trauma.

Effect of a methylxanthine preparation in the form of a retention enema on pulmonary function and theophylline levels in patients with acute bronchospasm

The goal of the current study was to determine whether administration of a methylxanthine preparation in the form of a retention enema (theophylline-diprophylline-proxyphylline combination, Neobiphyllin-Clys) has an effect similar to that of intravenous theophylline in the treatment of acute bronchospasm. In a randomized cross-over study 16 patients with a history of asthma were given 0.48 g of theophylline-ethylenediamine (TE) in the form of rapid intravenous infusion or a retention enema containing 400 mg theophylline, 600 mg diprophylline and 600 mg proxyphylline (TDP). Forced expiratory volume in the first second (FEV1) airways resistance (Rt) and serum theophylline levels were determined before administration of the drug and at 15 min, 30 min and hourly for a period of 6 h after administration of the medication. The results were significant at the 5% level. There were significant increases in serum theophylline levels with both TE and TDP. After administration of TE there were significant changes in FEV1 at 15 min and Rt at 30 min which persisted for 5 h after administration of the drug. Statistically significant differences in FEV1 were observed 60 min and in Rt 30 min after administration of TDP. These effects persisted for 6 h. The data document that a retention enema offers the advantage of prolonged action in comparison to intravenous infusion of theophylline in the treatment of acute bronchospasm.

Simultaneous reticulocyte and platelet counting on a clinical flow cytometer

Laser flow cytometric analysis is well suited to many clinical immunofluorescent and hematologic applications. One of these is automated reticulocyte and platelet enumerations. We have performed a clinical evaluation of a fluorescence laser flow cytometer reticulocyte and platelet enumeration method using the fluorochrome acridine orange. One hundred and thirty-two clinical specimens from inpatients in our comprehensive cancer center were analyzed for platelet counts and 101 samples from the same population were analyzed for reticulocyte counts by the flow cytometer and simultaneously by conventional techniques. Both the reticulocyte and platelet enumerations achieved a high degree of correlation with standard methods for the nonbone marrow-transplant patients studied (R = .989 for reticulocytes and R = .995 for platelets). Marrow transplant patients had a slightly poorer correlation coefficient for the reticulocyte enumeration (R = .923), but analysis of serial determinations of these patients' samples for reticulocyte counts revealed that results were more consistent over time with the automated method than with the traditional manual method. The laser flow cytometer fluorescence reticulocyte and platelet enumeration methods described are efficient, rapid, and reliable for platelet and reticulocyte counting.

Hemodynamic effects of molsidomine, isosorbide dinitrate, and nifedipine at rest and during exercise

In the first study the hemodynamic effects of standard doses of molsidomine (2 mg intravenously), isosorbide dinitrate (ISDN) (5 mg sublingually), and nifedipine (20 mg sublingually) were assessed at rest and under exercise conditions in a group of 30 patients with coronary heart disease. With the patients at rest both molsidomine and ISDN were associated with prompt reductions in left ventricular end-diastolic pressure and mean pulmonary artery pressure, whereas nifedipine was associated with slight reductions in left ventricular end-diastolic pressure and mean pulmonary artery pressure that did not attain statistical significance. Nifedipine and ISDN caused a decrease in mean aortic blood pressure, which resulted in a reactive increase in heart rate that was only significant with nifedipine. After administration of molsidomine, there was no significant change in mean aortic pressure at rest. There were reductions in stroke volume index and cardiac index after administration of molsidomine and ISDN. Nifedipine, however, was associated with significant increases in stroke volume index and cardiac index. None of the three test substances caused changes of contractility parameters. Under exercise conditions reductions in left ventricular end-diastolic pressure, mean pulmonary pressure, and mean aortic pressure were documented following administration of molsidomine, ISDN, and nifedipine. There were no major changes in maximum heart rate or stroke volume index during exercise with any of the three drugs. However, nifedipine was associated with a significant increase in cardiac index, whereas molsidomine and ISDN produced no major changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid accurate absolute granulocyte count determination during severe leukopenia using the flow cytometer

The absolute granulocyte count (AGC) in 125 blood samples from patients with total white blood cell counts of less than 1,000/microliter was estimated using three different methods, which were then compared for efficiency and accuracy. The three methods were 25 cell differential counts using Wright's-stained blood smears, granulocyte percentage estimates from WBC counting chambers, and combined narrow- and wide-angle light-scatter characteristics determined on a flow cytometer. A survey of clinical laboratories at University Hospital Cancer Centers revealed that the smear differential was the most-often-used method in those laboratories even when less than 25 cells could be counted. Consequently the data obtained from the counting chamber and flow cytometer methods were compared to the smear differential "standard" using linear regression, and outliers were identified. There was good correlation between AGC determined by smear differential and WBC counting chamber (correlation coefficient .911) and excellent correlation between the AGC determined by smear differential and the flow cytometer method (correlation coefficient .970). The flow cytometer method used in this investigation required minimal specimen preparation, and test results were available at a rate of 60 seconds/sample. The ease of sample preparation, speed, and statistical reliability of test results makes the flow cytometer an attractive alternate method of determining granulocyte counts on leukopenic patients as compared to the stained blood smear differential.

Do infant formula samples shorten the duration of breast-feeding?

To determine whether advertising by infant formula companies shortens the duration of breast-feeding, we randomly assigned 448 breast-feeding new mothers to either receive or not receive a formula sample packet upon discharge from a maternity ward. These mother, unaware of the study, were then telephoned 3 months post partum by a research assistant blind to the randomisation status. "Sample" mothers were less likely to still be breast-feeding at 1 month (78% vs 84%, p = 0.07) and more likely to have introduced solid foods by 2 months (18% vs 10%, p = 0.01). These trends became more significant in three vulnerable subgroups: less educated mothers, primiparas, and mothers who had been ill post partum. Our results suggest that infant formula samples may shorten the duration of breast-feeding and hasten the age at which solids are introduced.

Flow cytometric characterization of the response of Fanconi's anemia cells to mitomycin C treatment

DNA flow histogram analysis, using 33342 Hoechst as a stain, has been used to detect the effect of the potentially bifunctional alkylating agent, mitomycin C (MMC) on dermal fibroblasts from patients with Fanconi's anemia (FA), a hereditary human disease characterized by pancytopenia, hypersensitivity to DNA-crosslinking agents, congenital abnormalities and a predisposition for neoplasia. At 24 or 48 hr after a 2-hr exposure to 0.05 or 0.10 micrograms/ml MMC, (3)HdT incorporation was reduced to a greater extent in FA cells than in normal cells. Cells sorted from the last half of S phase showed a slightly greater inhibition of (3)HdT incorporation than did those sorted from the first half of S. Fanconi's anemia cells exhibited a marked accumulation in the G(2) + M peak of flow histograms following exposure to MMC. Twenty-four hr after treatment with .0.5 micrograms/ml MMC, the G(2) + M fraction of FA cells (eight lines) increased to more than 0.5 from a control value of approximately 0.02. Both normals (six lines) and heterozygotes (eight lines) showed, on the average, much less of a G(2) + M increment than did FA cells, even after exposure to 0.1 micrograms/ml MMC. Examination of cells sorted from the G(2) + M peak revealed that MMC-treated FA cells were blocked prior to mitosis. To determine whether the response of FA cells was specific for bifunctional alkylating agent, cells were also treated with ethylmethanesulfonate, a monofunctional agent. Twenty-four hours after exposure to 0.25 or 0.5 mg/ml ethylmethanesulfonate, FA and normal cells showed similar, small increases in the G(2) + M peak. The results suggest the utility of flow cytometry in the diagnostic evaluation of fibroblasts from patients suspected of having Fanconi's anemia.

Cytogenetic and flow cytometric studies of cells from patients with Fanconi's anemia

Cells from patients wtih Fanconi's anemia are unusually sensitive to agents which are capable of crosslinking DNA. This increased sensitivity can be detected both by cytogenetic and flow cytometric methods. An elevated frequency of chromosome aberrations, which is further exaggerated by exposure of cells to DNA crosslinking agents, is a general feature of Fanconi's anemia. Information about the formation of sister chromatid exchanges in this disease is less consistent. Cytogenetic analysis of cells from patients with Fanconi's anemia can be compromised by a low mitotic index. This is reflected in an accumulation of cells In the G2 phase of the cycle, after exposure to the bifunctional alkylating agent, mitomycin C. New methods for differentiating individuals with Fanconi's anemia from unaffected individuals should be of empirical use and might also facilitate mechanistic studies of this disease.

Further evidence for a non-random chromosomal abnormality in acute promyelocytic leukemia

We have previously reported on two patients with acute promyelocytic leukemia (APL) who had what appeared to be a deletion of chromosome No. 17. We now describe a third patient with APL. All three patients had a structural rearrangement involving No. 15 and No. 17. Our current interpretation of the chromosomal abnormality is that it is a reciprocal translocation, t (15;17) (q22; q21). Evidence that this is a consistent rearrangement associated with APL comes not only from our three patients, but also from two other published cases of APL, studied with banding, who also had an identical abnormality.