Influence of exciton dynamics on the interference of two photons from a microcavity single-photon source

One- and two-photon interference visibilities observed with the exciton emission from a quantum dot microcavity single-photon source are sensitive to the excitation conditions. In particular, the coherence time of the source is reduced with increasing pump power or excitation of the barrier layers. Furthermore, the two-photon interference visibility is affected by a long lived population of the biexciton state in the dot. This suggests that two-photon interference may be improved by controlling the exciton dynamics in the dot or by improved temporal resolution of the detection set-up.

Continuous operation of a one-way quantum key distribution system over installed telecom fibre

We demonstrate a robust, compact and automated quantum key distribution system, based upon a one-way Mach-Zender interferometer, which is actively compensated for temporal drifts in the photon phase and polarization. The system gives a superior performance to passive compensation schemes with an average quantum bit error rate of 0.87% and a duty cycle of 99.6% for a continuous quantum key distribution session of 19 hours over a 20.3km installed telecom fibre. The results suggest that actively compensated QKD systems are suitable for practical applications.

High performance single photon sources from photolithographically defined pillar microcavities

We demonstrate that single photons can be generated from single InAs/GaAs quantum dots in photolithographically defined pillar microcavities. Pillars with a 1.9 microm diameter cavity show a four fold enhancement in the radiative decay rate due to the Purcell effect and a photon collection efficiency into a lens of up to 10%. Measurements of the second order correlation function reveal a greater than fifty fold reduction in the multi-photon emission rate compared to a laser of the same intensity.

A phase II study of carboplatin and paclitaxel in esophageal cancer

BACKGROUND

This study was conducted to evaluate the efficacy and toxicity of combination carboplatin and paclitaxel in patients with esophageal cancer.

MATERIALS AND METHODS

Thirty-five patients were enrolled. Patients were treated with paclitaxel 200 mg/m(2) intravenously (i.v.) over 3 h and carboplatin i.v. at an AUC of 5 mg/h/ml. Thirty-three patients were assessable for toxicity and objective response.

RESULTS

A total of 166 treatment courses were administered with a median of five courses per patient. The objective response rate was 43% [90% confidence interval (CI) 0.3-0.58] by the intention-to-treat analysis. The median response duration was 2.8 months (90% CI 2.1-5.4). The median survival time was 9 months (90% CI 7-13.8) and the 1-year survival rate was 43% (90% CI 0.29-0.57). The major grade 3-4 toxicity observed was neutropenia, occurring in 17 patients (52%). There were no treatment-related deaths.

CONCLUSIONS

The combination of carboplatin and paclitaxel is an moderately active and tolerable regimen in advanced esophageal cancer.

Narrative representations of caregivers and emotion dysregulation as predictors of maltreated children's rejection by peers

This study examined whether maltreated children were more likely than nonmaltreated children to develop poor-quality representations of caregivers and whether these representations predicted children's rejection by peers. A narrative task assessing representations of mothers and fathers was administered to 76 maltreated and 45 nonmaltreated boys and girls (8-12 years old). Maltreated children's representations were more negative/constricted and less positive/coherent than those of nonmaltreated children. Maladaptive representations were associated with emotion dysregulation, aggression, and peer rejection, whereas positive/coherent representations were related to prosocial behavior and peer preference. Representations mediated maltreatment's effects on peer rejection in part by undermining emotion regulation. Findings suggest that representations of caregivers serve an important regulatory function in the peer relationships of at-risk children.

Parental maltreatment and emotion dysregulation as risk factors for bullying and victimization in middle childhood

Examined whether children who were maltreated by caregivers were more likely to bully others and to be at risk for victimization by peers. An additional focus was to investigate emotion's role in bullying and victimization among children at risk. Participants were 169 maltreated and 98 nonmaltreated boys and girls attending a summer day camp for inner-city children. As predicted, maltreated children were more likely than nonmaltreated children to bully other children. Bullying was especially prevalent among abused children who experienced maltreating acts of commission (physical or sexual abuse). Maltreatment also placed children at risk for victimization by peers. Gender did not moderate these findings, in that maltreated boys and girls appeared to be at similar risk for bullying and victimization. As expected, both bullies and victims evidenced problems with emotion regulation. Furthermore, logistic regression analyses suggested that emotion dysregulation made a unique contribution toward differentiating bullies and victims from children who did not evidence bully-victim problems. In addition, maltreatment's effects on children's risk for bullying and victimization were mediated by emotion dysregulation.

Narrative representations of caregivers and emotion dysregulation as predictors of maltreated children's rejection by peers

This study examined whether maltreated children were more likely than nonmaltreated children to develop poor-quality representations of caregivers and whether these representations predicted children's rejection by peers. A narrative task assessing representations of mothers and fathers was administered to 76 maltreated and 45 nonmaltreated boys and girls (8-12 years old). Maltreated children's representations were more negative/constricted and less positive/coherent than those of nonmaltreated children. Maladaptive representations were associated with emotion dysregulation, aggression, and peer rejection, whereas positive/coherent representations were related to prosocial behavior and peer preference. Representations mediated maltreatment's effects on peer rejection in part by undermining emotion regulation. Findings suggest that representations of caregivers serve an important regulatory function in the peer relationships of at-risk children.

Gemcitabine and UFT plus oral calcium folinate: phase I study

Gemcitabine (Gemzar) is a nucleoside analog increasingly used in the treatment of a variety of solid tumors. DNA synthesis is inhibited by gemcitabine by masked chain termination and via inhibition of ribonucleotide reductase. Synergy may exist between gemcitabine and other antimetabolites, including 5-fluorouracil. The varying patterns of dose-limiting toxicities to gemcitabine and UFT (uracil and tegafur in a 4:1 molar ratio) plus oral calcium folinate (Orzel) permit their use in combination. The primary aim of this phase I study is to determine the maximum tolerated doses of gemcitabine and UFT plus oral calcium folinate in patients with a variety of solid tumors. Only eight patients have been recruited to date, with myelosuppression being the main toxicity observed.

Reactive aggression among maltreated children: the contributions of attention and emotion dysregulation

Examined the complex interplay among emotion, attention, and aggression in a sample of 141 maltreated and 87 non-maltreated impoverished, inner-city children. Data were collected during a summer day camp, which provided an ecologically valid setting for studying children's behavior in social contexts. Maltreated children were more likely than non-maltreated children to be aggressive, with findings suggesting that physically abused children were at heightened risk for reactive aggression. Maltreated children also evidenced attention deficits, and subclinical or nonpathological dissociation was more likely among children who had experienced physical or sexual abuse. A history of abuse also predicted emotion dysregulation, affective lability/negativity, and socially inappropriate emotion expressions. This emotion dysregulation, fostered by poor attention modulation, was a mechanism of the effects of maltreatment on reactive aggression.

Reactive aggression among maltreated children: the contributions of attention and emotion dysregulation

Examined the complex interplay among emotion, attention, and aggression in a sample of 141 maltreated and 87 non-maltreated impoverished, inner-city children. Data were collected during a summer day camp, which provided an ecologically valid setting for studying children's behavior in social contexts. Maltreated children were more likely than non-maltreated children to be aggressive, with findings suggesting that physically abused children were at heightened risk for reactive aggression. Maltreated children also evidenced attention deficits, and subclinical or nonpathological dissociation was more likely among children who had experienced physical or sexual abuse. A history of abuse also predicted emotion dysregulation, affective lability/negativity, and socially inappropriate emotion expressions. This emotion dysregulation, fostered by poor attention modulation, was a mechanism of the effects of maltreatment on reactive aggression.

Emotion regulation among school-age children: the development and validation of a new criterion Q-sort scale

To foster the study of emotion regulation beyond infancy and toddlerhood, a new criterion Q-sort was constructed. In Study 1, Q-scales for emotion regulation and autonomy were developed, and analyses supported their discriminant validity. Study 2 further explored the construct validity of the Emotion Regulation Q-Scale within a sample of 143 maltreated and 80 impoverished children, aged 6 to 12 years. A multitrait-multimethod matrix and confirmatory factor analyses indicated impressive convergence among the Emotion Regulation Q-Scale and established measures of affect regulation. This new scale also was discriminable from measures of related constructs, including Q-sort assessments of ego resiliency. The use of this new measure was further supported by its ability to distinguish between maltreated and comparison children and between groups of well-regulated versus dysregulated children.

A phase II study of carboplatin and paclitaxel in the treatment of patients with advanced esophageal and gastric cancer

We initiated a phase II study to determine the efficacy of carboplatin and paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) in patients with advanced esophageal or gastric cancer. Objective tumor responses, duration of response, time to disease progression, overall survival, and toxicity profile are the end points evaluated in this study. The study includes patients with locally advanced metastatic or recurrent esophageal or gastric cancer with no history of prior chemotherapy or radiation treatment. Patients are required to have a performance status of 0 to 2 and no organ failure. Staging diagnostics include computed tomography scans and endoscopic ultrasound when appropriate. Starting dose of paclitaxel is 200 mg/m2, and carboplatin is given to achieve an area under the concentration-time curve of 5.0. Dose escalation is attempted if nadir counts permit. Seventeen patients have registered so far. Of those, three are not evaluable for efficacy analysis: one has not been on study long enough to be assessed for response and the other two are not assessable for objective tumor response. Three patients with gastric cancer have achieved partial responses. Two of five patients with esophageal cancer responded (partial response) to this treatment. Dose escalation by one step was feasible in approximately half the patients. There were no episodes of neutropenic fever. Carboplatin and paclitaxel given on an outpatient basis is well tolerated and an interesting regimen for the treatment of patients with advanced gastric or esophageal cancer.

Emotion regulation among school-age children: the development and validation of a new criterion Q-sort scale

To foster the study of emotion regulation beyond infancy and toddlerhood, a new criterion Q-sort was constructed. In Study 1, Q-scales for emotion regulation and autonomy were developed, and analyses supported their discriminant validity. Study 2 further explored the construct validity of the Emotion Regulation Q-Scale within a sample of 143 maltreated and 80 impoverished children, aged 6 to 12 years. A multitrait-multimethod matrix and confirmatory factor analyses indicated impressive convergence among the Emotion Regulation Q-Scale and established measures of affect regulation. This new scale also was discriminable from measures of related constructs, including Q-sort assessments of ego resiliency. The use of this new measure was further supported by its ability to distinguish between maltreated and comparison children and between groups of well-regulated versus dysregulated children.

Emotion regulation among school-age children: the development and validation of a new criterion Q-sort scale

To foster the study of emotion regulation beyond infancy and toddlerhood, a new criterion Q-sort was constructed. In Study 1, Q-scales for emotion regulation and autonomy were developed, and analyses supported their discriminant validity. Study 2 further explored the construct validity of the Emotion Regulation Q-Scale within a sample of 143 maltreated and 80 impoverished children, aged 6 to 12 years. A multitrait-multimethod matrix and confirmatory factor analyses indicated impressive convergence among the Emotion Regulation Q-Scale and established measures of affect regulation. This new scale also was discriminable from measures of related constructs, including Q-sort assessments of ego resiliency. The use of this new measure was further supported by its ability to distinguish between maltreated and comparison children and between groups of well-regulated versus dysregulated children.

Effects of incontinence care cleansing regimens on skin integrity

Soap and water and a no-rinse cleanser, with and without a moisture barrier, were examined for their effects as cleansing regimens on the perineal skin of 10 older female residents of an extended care facility. Each cleansing regimen was used for 3 weeks, with two weekly measurements obtained for erythema, pH, and transepidermal water loss. Results indicated that soap and water was the least efficacious regimen unless used with a moisture barrier. The no-rinse cleanser was better than soap and water in terms of skin effects and cost savings. The findings suggest that a no-rinse cleanser in conjunction with a moisture barrier is a more skin-preserving and cost-effective incontinence care cleansing regimen than soap and water for older female nursing home residents with incontinence.

Making the health care system 'safe' for persons with HIV infection or AIDS

If health care reform is implemented in states and nationally, the safety of this process needs to be examined for persons with human immunodeficiency virus (HIV) infection or the acquired immunodeficiency syndrome (AIDS). Reform should assure ongoing prevention and transmission control of HIV and continuous coverage of medical costs for persons ill with HIV or AIDS. These persons currently benefit from various state and federal categoric programs designed to assure access to preventive and personal care services. Washington State has passed health care reform legislation that envisions integrating these programs to provide a system of population-based and personal health care. This legislation was analyzed using existing epidemiologic and entitlement information about persons with HIV infection or AIDS in the state to assess its effect. The relationship between public health and personal care services will be a central concern for those with HIV infection or AIDS, and complete coverage of this group may be achieved relatively late in the process of implementing health care reform. Health personnel planning under health care reform will affect the delivery of HIV- and AIDS-related services. Including treatment of AIDS in the basic benefit package merits particular attention. These issues parallel those being faced by the nation as a whole as it seeks to ensure epidemic disease control and compassionate care for long-term disabling illness if health care reform is implemented.

Continuous-wave laser beam fanning in organic solutions: a novel phenomenon

If a low-power cw Ar(+) laser beam (~50 mW) is sent horizontally and focused on the entrance side of a cuvette containing an absorptive solution, the beam fans into the lower half of the cuvette instead of propagating through and forming self-phase-modulation fringes. We call this phenomenon self-beam fanning, which has been observed in several organic solutions. We present here several experimental results and a descriptive model of the phenomenon.

Health insurance coverage among persons with AIDS: results from a multistate surveillance project

To determine factors associated with health insurance coverage among persons with acquired immunodeficiency syndrome (AIDS), we interviewed 1958 persons 18 years of age or older who were reported to have AIDS in 11 states and cities. Overall, 25% had no insurance, 55% had public insurance, and 20% had private insurance. Factors associated with lack of insurance varied by current employment status. Employed persons with an annual household income of less than $10,000 were 3.6 times more likely to lack insurance than employed persons with a higher income. Unemployed persons diagnosed with AIDS for less than 1 year were two times more likely to lack health insurance than unemployed persons diagnosed for a longer time. Making insurance available to persons identified as most likely to lack insurance should improve access to care for persons with AIDS.

Urolithoscintigraphy: preliminary report of a new imaging modality for urolithiasis

We investigated the use of bisphosphonates, analogs of pyrophosphate that bind to mineralized tissue, to image renal calculi in vivo. Twenty stone-bearing kidneys in 15 patients without urinary obstruction were studied. 99mTechnetium-methylene diphosphonate was injected intravenously followed by 20 mg of furosemide 4 hours later, and images were obtained by gamma counter for 30 minutes. Areas of increased uptake corresponded with the sites of calculi, and even small or radiolucent calculi were easily seen. Counts in the region of each kidney, the L4 vertebral body, and a background area were combined to calculate a scintigram index (SI) for each kidney. The mean SI of the stone-bearing kidneys was 4.8 +/- 3.5 v 1.3 +/- 0.4 for the normal kidneys. There was correlation of the SI with stone composition and size but not with radiographic density. After correction for size, the SI of stone-bearing kidneys remained significantly higher than the SI of normal kidneys, but the differences between calculi of different compositions were diminished. Nonetheless, high SI values were associated with soft types of calculi and low values with hard types. Future investigations will reveal if this association is constant and if there is any relation between bisphosphonate uptake and response to lithotripsy. The sensitivity of urolithoscintigraphy to image small or radiolucent calculi may make it an effective technique for the assessment of residual fragments after lithotripsy.

HIV infection in hospitalized patients and Medicaid enrollees: the accuracy of medical record coding

To evaluate the accuracy of computerized medical-record coding for human immunodeficiency virus (HIV), medical charts were reviewed in six sites. In 7601 hospital and 867 Medicaid records with a listed diagnosis of HIV, the predictive value for HIV was 91% or higher. HIV was identified in 34% of 1155 Medicaid records listing immune disorder or illness in the acquired immunodeficiency syndrome (AIDS) surveillance definition (without an HIV code). In hospital and Medicaid records, AIDS was identified both in records listing AIDS and records listing HIV without AIDS. HIV codes on hospital and Medicaid records were highly predictive for HIV; undercoding of HIV occurred in Medicaid records.

The completeness of AIDS case reporting, 1988: a multisite collaborative surveillance project

OBJECTIVES

The purpose of this study was to evaluate the completeness of acquired immunodeficiency syndrome (AIDS) case reporting.

METHODS

Statewide or hospital-specific 1988 medical records were linked with AIDS surveillance in six sites. Medical records were reviewed for persons who had diagnoses suggesting human immunodeficiency virus (HIV) infection or AIDS but were not reported to AIDS surveillance by September 1989.

RESULTS

Among 4500 hospitalized persons diagnosed with AIDS through 1988 in the six sites, completeness of reporting was 92% (95% CI = 89%, 96%; range across sites = 89% to 97%). Completeness of reporting was high in males (92%), females (95%), Whites (95%), Blacks (90%), Hispanics (92%), men reporting sexual contact with men (92%), persons reporting injecting-drug use (91%), and persons exposed to HIV through heterosexual contact (99%). In Medicaid enrollees (two states), completeness of reporting was 99% (95% CI = 95%, 99%) in inpatients and 90% (95% CI = 79%, 90%) in outpatients. Of previously reported persons with AIDS, 82% were reported within 5 months of diagnosis.

CONCLUSIONS

Completeness of AIDS reporting was high, overall and in each major demographic and HIV exposure group. These results demonstrate that current surveillance data in these six sites provide timely and accurate information regarding persons with AIDS.

Phase I-II trial of pentoxifylline for the prevention of transplant-related toxicities following bone marrow transplantation

Disease relapse and transplant related toxicities have limited the application of bone marrow transplantation (BMT) in the treatment for hematologic malignancies. Because elevated levels of tumor necrosis factor alpha (TNF-alpha) have been correlated with the development of transplant related complications, we conducted a phase I-II trial of pentoxifylline (PTX), a xanthine derivative capable of down-regulating TNF-alpha production, in patients with hematologic malignancies undergoing BMT. Thirty consecutive adult patients (median age, 34) were entered and received either an allogeneic (n = 26) or autologous (n = 4) BMT. Patients were enrolled at increasing dose levels (1,200, 1,600, and 2,000 mg/d) from day -10 through day +100 posttransplant. PTX was well tolerated with no significant adverse side effects noted at any of the dose levels administered. The actuarial day 100 survival for these 30 patients was 90% (95% confidence interval 79% to 100%). When compared with a good risk control group, PTX recipients experienced less mucositis (3.7 +/- 1.1 v 18.7 +/- 1.1 days, P = .004), less hepatic venocclusive disease (10% v 65%, P = .001), a lower incidence of renal insufficiency (3% v 65%, P = .0003), required less days of total parenteral nutrition (TPN) (24.0 +/- 1.3 v 35.0 +/- 2.4, P = .001) and were discharged from the hospital earlier than controls (day 26.0 +/- 1.8 v 37.0 +/- 3.8, P = .01). In addition the incidence of graft-versus-host disease (GVHD) greater than or equal to grade II was also reduced among the PTX recipients (35% v 68%, P = .03). PTX at doses in excess of 1,200 mg/d further reduced the severity of mucositis, and TPN requirements resulting in earlier hospital discharge than patients receiving 1,200 mg/d of PTX. In this study oral administration of PTX in doses up to 2,000 mg/d was well tolerated and associated with a reduction in morbidity and mortality in patients undergoing BMT. Prospective randomized trials are currently in progress to test these preliminary observations.

Structure of the Abelson murine leukemia virus genome

Virions produced from cells transformed by A-MuLV contain a 30S, 5.6 kb RNA that can be translated in a cell-free system to form the characteristic A-MuLV protein. This RNA was mapped by heteroduplex methods using DNA probes from M-MuLV, the presumed parent of A-MuLV. The overall organization of the RNA was determined by using full-length M-MuLV reverse transcribed DNA and visualizing the heteroduplexes in the electron microscope. This showed that A-MuLV and M-MuLV have homologous sequences at both ends of their RNAs but that the central portion of the A-MuLV genome is not homologous to sequences in M-MuLV RNA. A precise measure of the lengths of the shared regions was obtained by using S1 nuclease to digest hybrids between 32P-labeled M-MuLV DNA and A-MuLV RNA; the resulting fragments were analyzed for their length by electrophoresis. The regions of homology were shown to be 1320 nucleotides long at the 5' end and 730 nucleotides long at the 3' end. Thus approximately 6200 nucleotides of the approximately 8300 in M-MuLV RNA were deleted when the A-MuLV genome was formed, but an insert of 3600 nucleotides, presumably derived from the normal murine genome, was inserted in place of the deleted region.

Virus production by Abelson murine leukemia virus-transformed lymphoid cells

Cell lines obtained by in vitro transformation of bone marrow with Abelson murine leukemia virus (A-MuLV) can be divided into three classes: producers, releasing reverse transcriptase-containing particles and infectious virus; nonproducers, releasing no viral particles; and defective producers, the most common phenotype, releasing particulate reverse transcriptase in the absence of infectious virus. When such cell lines were analyzed 1 to 2 weeks after their isolation, however, all produced infectious virus. Because these cell lines were carried in culture, many ceased to release infectious virus but produced defective virions. One defective producer, SWR4, has been extensively studied. The particles it produces have the same density as that of virions of Moloney murine leukemia virus (M-MuLV). The particles contain no 35 to 70S RNA, as determined by analysis of [3H]uridine-labeled particles, and exhibit no endogenous reverse transcriptase activity. Although the reverse transcriptase enzyme is of normal size, the major structural protein of the defective virions has a molecular weight of 28,000 (p28), in contrast to the p30 of M-MuLV, and no viral glycoprotein was evident. The defective particles do not appear to arise either from the helper virus or from Abelson virus. An alteration of the protein of the helper virus is an unlikely source of p28 because particles produced by lymphoid cells transformed with another strain of M-MuLV as helper (M-MuLV-TB) contained p28 with an unaltered cleavage pattern, although M-MuLV-TB p30 differs from M-MuLV p30. The A-MuLV genome lacks the capacity to code for the reverse transcriptase virions. Clones of fibroblasts infected with A-MuLV only occasionally produce defective particles. The defective particles therefore probably arose from an endogenous virus that is preferentially expressed in the class of lymphoid cells transformed by A-MuLV. This interpretation implies that the majority of A-MuLV-transformed lymphoid cells completely lose expression of the helper virus genome.

In vitro synthesis of a 9 kbp terminally redundant DNA carrying the infectivity of Moloney murine leukemia virus

Detergent-disrupted virions of Moloney murine leukemia virus synthesize a 9 kbp double-stranded infectious DNA. It contains mainly full-length, single-stranded DNA, and its infectivity and size are insensitive to digestion by the single-strand-specific S1 nuclease. Analysis of fragmentation of the DNA using restriction endonucleases has shown that it is indistinguishable from the linear double-stranded DNA synthesized in infected cells. On the basis of the positions of the cleavage sites for a number of enzymes, the 9 kbp DNA has a 575 base direct terminal repetition. It is longer than the viral RNA at both ends, evidently due to repetitive copying of segments of the RNA. Virions also synthesize an 8.4 kbp double-stranded circular DNA that lacks one copy of the terminal repetition, as well as viral DNA longer than 9 kbp. The enzymatic machinery in the virions of retroviruses therefore appears to be responsible for all the steps involved in making fully double-stranded linear and one form of circular DNA.

High frequency of aberrant expression of Moloney murine leukemia virus in clonal infections

Clones of cells were isolated from single virus-single cell infections of NIH/3T3 cells with Moloney murine leukemia virus. Approximately one third of such clones aberrantly expressed viral gene functions. One clone produced virus with altered plaque morphology, while others failed to produce particles able to make plaques on XC cells. In addition, clones that made particles lacking reverse transcriptase were found, and these did not synthesize the reverse transcriptase precursor Pr180 gag-pol. One clone (M23) lacked any detectable glycoprotein or reverse transcriptase. Despite these defects, each clone released particles of type C morphology, suggesting that gag gene function alone may be sufficient for particle production. All the particles contained viral RNA of 60-70S that was composed of the normal 35S size subunits except for M23, which had a deletion in the viral genome of approximately 1000-1500 nucleotides. A variety of defective clones were also isolated following infection of rat cells with Moloney virus. It is apparent that the murine leukemia virus genome is ofter mutated by spontaneous processes generating a wide range of phenotypes.

Identification of an Abelson murine leukemia virus-encoded protein present in transformed fibroblast and lymphoid cells

Extracts from lymphoid and fibroblast cell lines transformed by Abelson murine leukemia virus (A-MuLV) contain a protein of molecular weight 120,000 (P120). Immunoprecipitation with specific sera shows that P120 contains regions homologous to the 5'-terminal segment of the MULV gag gene complex--p15, p12, and at least part of p30--but lacks detectable determinants of p10, reverse transcriptase, and the envelope glycoprotein. P120 is phosphorylated and has an intracellular half-life of 3--6 hr. In vitro translation of virion RNA from A-MuLV, with Moloney MuLV as helper, yields a product of molecular weight 120,000 with serological reactivity similar to that of the cellular P120. Translation of the RNA from the helper gave no P120. P120 is expressed in all lymphoid and fibroblastic cell lines we have tested that were transformed by A-MuLV but is not detectable in a lymphoid line in which the A-MuLV genome was established by infection but was not responsible for the transformation. Expression of P120 is selectively retained in clones of A-MuLV-transformed lymphocytes that convert to a nonproducer state after loss of expression of helper MuLV intracellular precursors. These results suggest that the P120 product of the A-MuLV genome may be responsible for maintenance of the transformed phenotype of lymphoid and fibroblast cells transformed by the virus.

Viability of cells in ethanol. Role of alcohol dehydrogenase

Rodent cells were found to contain a high level of alcohol dehydrogenase activity which was not inducible. Other hepatoma and nonhepatoma cell lines were tested and found to contain lower but measurable levels of alcohol dehydrogenase.