bluuebunny/crossref_metadata_2025 huggingface dataset:
How Much Is Enough? Trauma Recall and the Exposure Therapy Process
Authors: Morrison Krystal I. , Beidel Deborah C. , Bowers Clint A.
Published: January 2020

Theoretical models of posttraumatic stress disorder (PTSD) as well as exposure therapy (EXP) methodology suggest that trauma recall is crucial to altering the conditioned fear response associated with PTSD. However, it is unclear whether limited recall of the trauma event attenuates treatment outcomes. This study examined whether the extent of difficulty recalling aspects of a traumatic event affected fear activation, habituation, number of sessions, session length, and diagnostic outcomes in 166 Operation Enduring Freedom, Operation Iraqi Freedom, and Operation New Dawn veterans. Extent of trauma recall difficulty neither attenuated veterans' ability to achieve fear activation and habituation nor affected treatment outcomes. Findings suggest that even veterans who reported greater difficulty recalling their trauma event can engage successfully and benefit from EXP. This research is the first to examine trauma event recall in the context of the EXP process and contributes to the current body of literature that aims to address the question: “For whom do treatments work?”
Primary Care Providers' Perspectives on Prescribing Antidepressant Medication to Latino Immigrant Patients
Authors: Kirkpatrick Laura , Watson Maria Rosa , Serrano Adriana , Campoli Marcela , Kaltman Stacey I. , Talisman Nicholas , Green Bonnie L.
Published: January 2020

Latinos in the United States are less likely to take antidepressants than non-Latino whites, and more likely to prefer depression treatment in primary care. This preliminary study comprised focus groups (2) with primary care providers (12) serving uninsured immigrant Latinos regarding their experiences prescribing and counseling patients about antidepressants. Barriers and challenges included health literacy, language barriers, and illiteracy; perceived stigma; patients' concerns about addiction, polypharmacy, and adverse effects; time constraints of office visits; and difficulty discussing comorbid posttraumatic stress disorder. Messages providers try to share with patients included allowing time for medications to work, taking medications daily as prescribed, mechanisms of action, weighing risks versus benefits, and flexible options for treatment. Providers' recommendations for improving this process included better low-literacy, culturally appropriate written materials with pictures or videos discussing depression. More research is needed to understand patients' and providers' needs in optimizing counseling about antidepressants, particularly regarding underserved and at-risk US populations.
Mood Disorders and Increased Risk of Noncommunicable Disease in Adults With HIV
Authors: Castilho Jessica L. , Rebeiro Peter F. , Shepherd Bryan E. , Nash Robertson , Adams Rodney S. , Turner Megan , Furukawa Sally S. , Hulgan Todd , Koethe John R. , Sterling Timothy R.
Published: January 2020

Background:

People living with HIV (PLWH) experience high rates of mood disorders (major depression and bipolar affective disorder) which in the general population have been associated with noncommunicable disease (NCD) risk. We examined whether prevalent mood disorders are associated with incident NCDs and multimorbidity (accumulation of ≥2 NCDs) in PLWH.

Setting:

Adult HIV clinic cohort in Nashville, Tennessee, between 1998 and 2015.

Methods:

PLWH with ≥1 year of follow-up in the clinic were assessed for cardiovascular disease, metabolic syndrome (any 3 of hypertension, hyperlipidemia, diabetes, or obesity), chronic kidney and liver disease, non–AIDS-defining cancers, and dementia. Only mood disorders documented during the first year of care were included. Cumulative incidence and adjusted subhazard ratios (aSHRs) were calculated for risk of NCDs and multimorbidity with death as a competing risk. Multivariable Cox models estimated mortality risk after multimorbidity.

Results:

Of 4140 adults, 24% had a mood disorder diagnosed in the first year of care, 51% had ≥1 NCD at baseline, and there were 2588 incident NCDs during the study period. Mood disorders were associated with increased risk of first NCD (aSHR = 1.29, 95% confidence interval: 1.06 to 1.57), incident multimorbidity (aSHR ranging from 1.04 to 1.42), and metabolic syndrome (aSHR = 1.29, 95% confidence interval: 1.02 to 1.64). Mood disorders were not conclusively associated with mortality risk after multimorbidity.

Conclusions:

PLWH with mood disorders were at increased risk of incident NCDs and multimorbidity, particularly metabolic syndrome. Focused prevention and treatment of NCDs may reduce the burden of multimorbidity in this high-risk group.
A Multicenter Randomized Controlled Trial of Intensive Group Therapy for Tobacco Treatment in HIV-Infected Cigarette Smokers
Authors: Stanton Cassandra A. , Kumar Princy N. , Moadel Alyson B. , Cunningham Chinazo O. , Schechter Clyde B. , Kim Ryung S. , Shuter Jonathan
Published: January 2020

Background:

Tobacco use has emerged as the leading killer of persons living with HIV (PLWH) in the United States. Little is known about the efficacy of tobacco treatment strategies in PLWH.

Design:

Randomized controlled trial comparing Positively Smoke Free (PSF), an intensive group therapy intervention targeting HIV-infected smokers, to brief advice to quit. All participants were offered a 12-week supply of nicotine patches.

Methods:

A cohort of 450 PLWH smokers, recruited from HIV-care centers in the Bronx, New York, and Washington, DC, were randomized 1:1 into the PSF or brief advice to quit conditions. PSF is an 8-session program tailored to address the needs and concerns of HIV-infected smokers and delivered by a trained smoking cessation counselor and PLWH ex-smoker peer pair. The primary outcome was biochemically confirmed, 7-day point-prevalence abstinence at 6 months.

Results:

In the intention to treat analysis, PSF condition subjects had nearly double the quit rate of controls, 13% vs. 6.6% [odds ratio = 2.10 (95% confidence interval = 1.10 to 4.14), P = 0.04], at 3 months, but no significant difference in abstinence was observed at 6 months. PSF participants exhibited lower nicotine dependence and higher self-efficacy to resist smoking temptations at both 3 and 6 months compared with controls. Lower educational attainment, current cocaine use, past use of nicotine patches, and higher distress tolerance were significant predictors of continued smoking at 6 months.

Conclusions:

These findings suggest a role for group therapy among tobacco treatments for PLWH smokers, but strategies to augment the durability of early effects are needed.
The HIV Pre-exposure Prophylaxis (PrEP) Cascade at NYC Sexual Health Clinics: Navigation Is the Key to Uptake
Authors: Pathela Preeti , Jamison Kelly , Blank Susan , Daskalakis Demetre , Hedberg Trevor , Borges Christine
Published: January 2020

Background:

Clinics providing sexual health care pose unique opportunities to implement HIV pre-exposure prophylaxis (PrEP) programs. The PrEP program at New York City's Sexual Health Clinics provides intensive on-site navigation for linkage to PrEP care. We assessed uptake of this intervention.

Methods:

We categorized men who have sex with men (MSM) without HIV hierarchically as having had (1) HIV post-exposure prophylaxis (PEP) use (past year); or (2) selected sexually transmitted infections (STI) (past year); or (3) HIV-diagnosed sex/needle-sharing partners (past 6 months); or (4) expressed interest in PrEP (day of clinic visit). We constructed PrEP cascades and used multivariable regression to examine acceptance of PrEP navigation, referral to a PrEP provider, linkage (<60 days), and PrEP prescription.

Results:

One thousand three hundred one of 2106 PrEP (62%) patients accepted navigation. Of those, 55% (718/1301) were black or Hispanic MSM. STI and PEP patients had lowest navigation acceptance levels (35%–46%). Of navigated patients, 56% (628/1114) accepted referrals, 46% (288/628) linked to PrEP providers, and 82% (235/288) were prescribed PrEP; overall, 11% of those offered navigation (235/2106) received prescriptions. Navigated MSM with PEP history [adjusted prevalence ratio (aPR) 1.34, 95% confidence interval (CI): 1.16 to 1.56)], previous STI (aPR 1.28, 95% CI: 1.12 to 1.45), or HIV-diagnosed partners (aPR 1.18, 95% CI: 1.01 to 1.37) were more likely than those with PrEP interest to accept referrals. Probability of linkage varied by insurance status; prescription did not vary by patient factors.

Conclusions:

Although MSM in key priority groups (eg, previous STI) showed low navigation uptake, those who accepted navigation were likely to be referred for PrEP, suggesting a need for expanded up-front engagement.
A Cross-sectional Analysis of Insurance Coverage of Extremity Contouring After Massive Weight Loss
Authors: Ngaage Ledibabari M. , Wasicek Philip J. , Puthumana Joseph , Kambouris Adrienne R. , Tannouri Sami , Rada Erin M. , Kligman Mark D. , Rasko Yvonne M.
Published: January 2020

Introduction

After bariatric surgery, patients often experience redundant skin in the upper arms and medial thighs as sequelae of massive weight loss. Insurance companies have unpredictable criteria to determine the medical necessity of brachioplasty and thighplasty, which are often ascribed as cosmetic procedures. We evaluated current insurance coverage and characterized policy criteria for extremity contouring in the postbariatric population.

Methods

We conducted a cross-sectional analysis of insurance policies for coverage of brachioplasty and thighplasty in January 2019. Insurance companies were selected based on their state enrolment data and market share. A web-based search and direct calls were conducted to identify policies. A comprehensive list of standard criteria was compiled based on the policies that offered coverage.

Results

Of the 56 insurance companies assessed, half did not provide coverage for either procedure (n = 28). No single criterion featured universally across brachioplasty and thighplasty policies. Functional impairment was the most commonly cited condition for preapproval of brachioplasty and/or thighplasty (94%). Conversely, minimum weight loss was the least frequent criterion within the insurance policies (6%). Only 5% of the insurance companies (n = 3) would consider coverage of liposuction-assisted lipectomy as a modality for brachioplasty or thighplasty.

Conclusions

We propose a comprehensive list of reporting recommendations to help optimize authorization of extremity contouring in the postbariatric population. There is great intercompany variation in preapproval criteria for brachioplasty and thighplasty, illustrating an absence of established recommendations or guidelines. High-level evidence and investigations are needed to ascertain validity of the limited coverage criteria in current use.
Endovascular Repair of Blunt Thoracic Aortic Trauma is Associated With Increased Left Ventricular Mass, Hypertension, and Off-target Aortic Remodeling
Authors: Kamenskiy Alexey , Aylward Paul , Desyatova Anastasia , DeVries Matthew , Wichman Christopher , MacTaggart Jason
Published: January 2020

Background:

Aortic elasticity creates a cushion that protects the heart from pressure injury, and a recoil that helps perfuse the coronary arteries. TEVAR has become first-line therapy for many aortic pathologies including trauma, but stent-grafts stiffen the aorta and likely increase LV afterload.

Objective:

Test the hypothesis that trauma TEVAR is associated with LV mass increase and adverse off-target aortic remodeling.

Methods:

Computed Tomography Angiography (CTA) scans of 20 trauma TEVAR patients (17 M/3 F) at baseline [age 34.9 ± 18.5 (11.4–71.5) years] and 5.1 ± 3.1 (1.1–12.3) years after repair were used to measure changes in LV mass, LV mass index, and diameters and lengths of the ascending thoracic aorta (ATA). Measurements were compared with similarly-aged control patients without aortic repair (21 M/21 F) evaluated at similar follow-ups.

Results:

LV mass and LV mass index of TEVAR patients increased from 138.5 ± 39.6 g and 72.35 ± 15.17 g/m2 to 173.5 ± 50.1 g and 85.48 ± 18.34 g/m2 at the rate of 10.03 ± 12.79 g/yr and 6.25 ± 10.28 g/m2/yr, whereas in control patients LV characteristics did not change. ATA diameters of TEVAR patients increased at a rate of 0.60 ± 0.80 mm/yr, which was 2.4-fold faster than in controls. ATA length in both TEVAR and control patients increased at 0.58 mm/yr. Half of TEVAR patients had hypertension at follow-up compared to only 5% at baseline.

Conclusions:

TEVAR is associated with LV mass increase, development of hypertension, and accelerated expansile remodeling of the ascending aorta. Although younger trauma patients may adapt to these effects, these changes may be even more important in older patients with other aortic pathologies and diminished baseline cardiac function.
Current and Projected Financial Burden of Emergency General Surgery for Adults in Scotland's Single Payer Healthcare System
Authors: Wohlgemut Jared M. , Ramsay George , Boyers Dwayne , Jansen Jan O.
Published: January 2020

Objective:

To calculate the current and projected financial burden of EGS hospital admissions in a single-payer healthcare system.

Summary of Background Data:

EGS is an important acute care service, which demands significant healthcare resources. EGS admissions and associated costs have increased over time, associated with an aging demographic. The National Health Service is the sole provider of emergency care in Scotland.

Methods:

Principal, high and low Scottish population projections were obtained for 2016 until 2041. EGS admission data were projected using an ordinary least squares linear regression model. An exponential function, fitted to historical length of hospital stay (LOS) data, was used to project future LOS. Historical hospital unit cost per bed day was projected using a linear regression model. EGS cost was calculated to 2041 by multiplying annual projections of population, admission rates, LOS, and cost per bed day.

Results:

The adult (age >15) Scottish population is projected to increase from 4.5 million to 4.8 million between 2016 and 2041. During this time, EGS admissions are expected to increase from 83,132 to 101,090 per year, cost per bed day from £786 to £1534, and overall EGS cost from £187.3 million to £202.5 million.

Conclusions:

The future financial burden of EGS in Scotland is projected to increase moderately between 2016 and 2041. This is in sharp contrast to previous studies from settings such as the United States. However, if no further reductions in LOS or cost per bed day are made, especially for elderly patients, the cost of EGS will rise dramatically.
Dissociated hippocampal neurons exhibit distinct Zn2+dynamics in a stimulation method-dependent manner
Authors: Sanford Lynn , Palmer Amy E.
Published: January 2020

Ionic Zn2+has increasingly been recognized as an important neurotransmitter and signaling ion in glutamatergic neuron pathways. Intracellular Zn2+transiently increases as a result of neuronal excitation, and this Zn2+signal is essential for neuron plasticity, but the source and regulation of the signal is still unclear. In this study we rigorously quantified Zn2+, Ca2+and pH dynamics in dissociated mouse hippocampal neurons stimulated with bath application of high KCl or glutamate. While both stimulation methods yielded Zn2+signals, Ca2+influx, and acidification, glutamate stimulation induced more sustained high intracellular Ca2+and a larger increase in intracellular Zn2+. However, the stimulation-induced pH change was similar between conditions, indicating that a different cellular change is responsible for the stimulation-dependent difference in Zn2+signal. This work provides the first robust quantification of Zn2+dynamics in neurons using different methods of stimulation.
How does cultural capital affect educational performance: Signals or skills?
Authors: Breinholt Asta , Jæger Mads Meier
Published: January 2020

In this paper, we test two mechanisms through which cultural capital might affect educational performance: (a) teachers misinterpreting cultural capital as signals of academic brilliance and (b) cultural capital fostering skills in children that enhance educational performance. We analyse data from the ECLS‐K and ECLS‐K:2011 from the United States and focus on three aspects of children’s cultural capital: participation in performing arts, reading interest and participation in athletics and clubs. We find that (1) none of the three aspects of cultural capital that we consider affects teachers’ evaluations of children’s academic skills; (2) reading interest has a direct positive effect on educational performance; and (3) the direct effect of reading interest on educational performance does not depend on schooling context. Our results provide little support for the hypothesis that cultural capital operates via signals about academic brilliance. Instead, they suggest that cultural capital fosters skills in children that enhance educational performance. We discuss the theoretical implications of our findings.
Deservingness put into practice: Constructing the (un)deservingness of migrants in four European countries
Authors: Nielsen Mathias Herup , Frederiksen Morten , Larsen Christian Albrekt
Published: January 2020

The increased comparative research on perceptions of public welfare deservingness studies the extent to which different subgroups of citizens are deemed worthy or unworthy of receiving help from the welfare state. The concept of deservingness criteria plays a crucial role in this research, as it theorizes a universal heuristic that citizens apply to rank people in terms of their welfare deservingness. Due to the mainly quantitative nature of the research and despite the indisputable progress it has made, the subjective existence and actual application of these deservingness criteria remain a bit of a black box. What criteria of deservingness do citizens actually apply, and how do they apply them? This article opens the black box of welfare deservingness and sheds light on the nature and practice of deservingness criteria. Empirically, the paper explores how the deservingness of immigrants is discussed and established within 20 focus groups conducted in Slovenia, Denmark, UK, and Norway in 2016 with a total of 160 participants. All 20 focus groups discussed the welfare deservingness of immigrants based on similar vignette stimuli. Our analysis shows that (1) deservingness criteria are used both to construct images of target groups and as normative yardsticks; (2) deservingness criteria do not work independently of each other, but rather co‐function in specific hybridized discourses; and (3) the moral logic of deservingness is supplemented by alternative moral logics, at least in the case of migrants.
Correlation between new OCT parameters and metamorphopsia in advanced stages of epiretinal membranes
Authors: Alkabes Micol , Fogagnolo Paolo , Vujosevic Stela , Rossetti Luca , Casini Giamberto , De Cillà Stefano
Published: January 2020

Purpose

To correlate metamorphopsia provided by M‐CHARTS and ectopic inner foveal layers (EIFL) or ‘central bouquet’ abnormality (CBA) in patients with advanced stages of epiretinal membrane (ERM) following the novel Optical Coherence Tomography (OCT)‐based grading scheme.

Methods

In 60 eyes of 57 patients affected by ERM (stages 3 and 4), the degree of metamorphopsia using the M‐CHARTS was evaluated (M‐SCORE) and correlated with EIFL, CBA and central foveal thickness (CFT) as measured on OCT scans.

Results

A total of 37 and 23 eyes were diagnosed having ERM stages 3 and 4, respectively. Mean vertical and horizontal M‐SCORE (M‐V and M‐H) were 0.64 ± 0.43 and 0.58 ± 0.37 standard deviations, respectively. Mean M‐SCORE exhibited a statistically significant correlation with EIFL and CFT (both p < 0.0001), but not with CBA (p = 0.84). Analysing the direction of metamorphopsia separately, M‐H and M‐V were significantly correlated with EIFL (both p < 0.0001), but not with CBA thickness (p = 0.70 and 0.33 respectively). Ectopic inner foveal layers (EIFL) was significantly influenced by the presence of CBA (CBA present, 158.29 ± 63.53 micron; CBA absent, 107.05 ± 94.13 micron, p = 0.04). No significant differences were found for both M‐V and M‐H with respect to the presence of CBA.

Conclusions

Based on the novel OCT‐based grading scheme for ERMs, our results demonstrate that EIFL, but not CBA, might be considered a good indicator for metamorphopsia in patients with advanced ERMs.
Production and Characteristics of Hemolysins of
Escherichia coli
Authors: Snyder Irvin S. , Koch Nancy A.
Published: January 2020

Snyder, Irvin S.
(University of Iowa, Iowa City),
and Nancy A. Koch
. Production and characteristics of hemolysins of
Escherichia coli
. J. Bacteriol.
91:
763–767. 1996.—Filterable and nonfilterable hemolysins were produced by
Escherichia coli
in beef-heart infusion, casein hydrolysate, and chemically defined media. Differences were found among the three media in the time of appearance and in the relationship between production of these two hemolysins. The nonfilterable hemolysin produced in the three media, as well as the filterable hemolysin produced in the beef-heart infusion medium, were destroyed in 1 hr at 56 C. The filterable hemolysin produced in the casein hydrolysate and chemically defined media was unaffected by exposure to 56 C for 1 hr. Formalin inactivated the hemolysins produced in all three media. The optimal
p
H for activity of the nonfilterable hemolysin varied with time of production, whereas the optimal
p
H for the filterable hemolysin was constant. Certain carbohydrates were required for the production of filterable hemolysin by
E. coli
grown in casein hydrolysate and chemically defined media.
Mechanism of Action of Nalidixic Acid on
Escherichia coli
III. Conditions Required for Lethality
Authors: Deitz William H. , Cook Thomas M. , Goss William A.
Published: January 2020

Deitz, William H.
(Sterling-Winthrop Research Institute, Rensselaer, N.Y.),
Thomas M. Cook, and William A. Goss
. Mechanism of action of nalidixic acid on
Escherichia coli
. III. Conditions required for lethality. J. Bacteriol.
91:
768–773. 1966.—Nalidixic acid selectively inhibited deoxyribonucleic acid (DNA) synthesis in cultures of
Escherichia coli
15TAU. Protein and ribonucleic acid synthesis were shown to be a prerequisite for the bactericidal action of the drug. This action can be prevented by means of inhibitors at bacteriostatic concentrations. Both chloramphenicol, which inhibits protein synthesis, and dinitrophenol, which uncouples oxidative phosphorylation, effectively prevented the bactericidal action of nalidixic acid on
E. coli
. The lethal action of nalidixic acid also was controlled by transfer of treated cells to drug-free medium. DNA synthesis resumed immediately upon removal of the drug and was halted immediately by retreatment. These studies indicate that nalidixic acid acts directly on the replication of DNA rather than on the “initiator” of DNA synthesis. The entry of nalidixic acid into cells of
E. coli
was not dependent upon protein synthesis. Even in the presence of an inhibiting concentration of chloramphenicol, nalidixic acid prevented DNA synthesis by
E. coli
15TAU.
Mechanism of Action of Nalidixic Acid on
Escherichia coli
IV. Effects on the Stability of Cellular Constituents
Authors: Cook Thomas M. , Deitz William H. , Goss William A.
Published: January 2020

Cook, Thomas M.
(Sterling-Winthrop Research Institute, Rensselaer, N.Y.),
William H. Deitz, and William A. Goss
. Mechanism of action of nalidixic acid on
Escherichia coli
. IV. Effects on the stability of cellular constituents. J. Bacteriol.
91:
774–779. 1996.—Treatment of
Escherichia coli
15TAU with nalidixic acid resulted in degradation of the nucleic acids of the cells, whereas protein was unaffected. Deoxyribonucleic acid (DNA) degradation appeared to be more extensive than ribonucleic acid degradation during periods of comparable bactericidal action. The onset of DNA degradation was evident prior to a measurable bactericidal effect. However, within the range of 2 to 20%, DNA degradation was accompanied by a decrease in viable cell numbers. Degradation of DNA to acid-soluble material occurred only under conditions permitting the bactericidal action of nalidixic acid. Arrest of the bactericidal action of nalidixic acid by the addition of dinitrophenol or chloramphenicol also inhibited DNA degradation. The acid-soluble products, which were excreted into the medium, have not been characterized completely, but probably were not phosphorylated.
Effect of Visible Light on Canine Distemper Virus
Authors: Nemo George J. , Cutchins Ernest C.
Published: January 2020

Nemo, GeorgeJ. (The Catholic University of America, Washington, D.C.),and Ernest C. Cutchins. Effect of visible light on canine distemper virus. J. Bacteriol.91:798–802. 1966.—Canine distemper virus (CDV) was inactivated by visible light. The virus was light-sensitive in fluid suspension (in vitro) as well as during intracellular replication (in vivo). The addition of calf serum or glutathione reduced the extent of inactivation. CDV was less sensitive when suspended in distilled water or in the amino acid or Earle's salts components of the minimal essential medium of Eagle than when suspended in the vitamin component of the minimal essential medium of Eagle or in riboflavine (0.1 mg per liter). These findings indicate that, whereas some ingredient of the medium may enhance light sensitivity, its presence is not necessary for light inactivation of CDV. It is proposed that some substance derived from the host cell and intimately associated with the virus particle serves to render CDV light-sensitive.
High Resolution Autoradiography of
Escherichia coli
Cells Infected with Bacteriophage R17
Authors: Granboulan Nicole , Franklin Richard M.
Published: January 2020

Granboulan, Nicole
(Institute de Recherches sur le Cancer, Villejuif, Seine, France),
and Richard M. Franklin
. High-resolution autoradiography of
Escherichia coli
cells infected with bacteriophage R17. J. Bacteriol.
91:
849–857. 1966.—The ultrastructural alterations in
Escherichia coli
infected with the RNA bacteriophage R17 were further investigated by means of the technique of high-resolution autoradiography. Tritiated precursors to ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and protein were employed in separate experiments. A striking inhibition of cellular RNA, DNA, and protein synthesis was noted. Whereas normal RNA synthesis occurs in the nucleoid, in infected cells RNA synthesis is predominantly cytoplasmic, but later in the latent period, and during the stage of active viral growth, the label is localized in a polar region. In the late stages of viral growth, RNA synthesis occurs only around the crystals. Protein synthesis also becomes localized in a polar region, but DNA synthesis remains confined to the nucleoid. Under conditions of chloramphenicol inhibition of viral-coat protein synthesis, RNA label is localized in the paranuclear lesion, providing further indication that RNA forms this fibrillar structure.
Growth Phases of
Mycoplasma
in Liquid Media Observed with Phase-Contrast Microscope
Authors: Razin Shmuel , Cosenza Benjamin J.
Published: January 2020

Razin, Shmuel
(University of Connecticut, Storrs),
and Benjamin J. Cosenza
. Growth phases of
Mycoplasma
in liquid media observed with phase-contrast microscope. J. Bacteriol.
91:
858–869. 1966—Growth of 11
Mycoplasma
strains in liquid media was followed by phase-contrast microscopy. A similar pattern of development was common to all strains. Branching filaments, 0.3 to 0.4 μ thick, characterized the early logarithmic phase of growth. The length of the filaments varied according to the strain tested and the growth medium. Addition of oleic acid to the medium induced the formation of very long filaments by
M. laidlawii
strain B. Upon aging, the filaments were found to break up into chains of coccoid elements. These chains further fragmented to yield shorter chains and single coccoid elements, which characterized the stationary and decline phases of growth. The size of the coccoid elements increased from 0.3 to 0.4 μ, when formed in the filaments, to 0.6 to 0.8 μ after being released from the chains. Further increase in the size of the cells took place at the decline phase of growth, leading to the formation of very large cells reaching a diameter of 10 to 20 μ. However, these large cells had the appearance of empty vesicles and were apparently nonviable as indicated by viable-count experiments.
Metabolism of Methylated Purines in
Escherichia coli
: Derepression of Purine Biosynthesis
Authors: Love Samuel H. , Remy Charles N.
Published: January 2020

Love, Samuel
H. (Bowman Gray School of Medicine, Wake Forest College, Winston-Salem, N.C.),
and Charles N. Remy
. Metabolism of methylated purines in
Escherichia coli
: derepression of purine biosynthesis. J. Bacteriol.
91:
1037–1049. 1966.—Various methylated purines were examined for their effects on growth of purine-requiring mutants of
Escherichia coli
, strains W-11 and B-96, and for their effects on purine biosynthesis. 6-Methylaminopurine and 6-methoxypurine stimulated the accumulation of purine precursor derivatives (ribosyl-5-aminoimidazole and ribosyl-5-amino-4-imidazole carboxamide) beyond their ability to support growth. Information obtained from in vivo and in vitro systems demonstrated that the metabolism of 6-methylaminopurine and 6-methoxypurine utilized identical pathways. The riboside derivatives are formed either by direct ribosidation via nucleoside phosphorylase or, indirectly, by dephosphorylation of the 5′-phosphoribosyl derivatives which are synthesized via adenylate pyrophosphorylase. Information obtained with the aid of strain W-11/DAP (lacking adenylate pyrophosphorylase) demonstrated that both pathways were important to the growing cells. Regardless of the metabolic pathway by which they are synthesized, the ribosyl derivatives are demethylaminated (demethylated) by adenosine deaminase to yield inosine. The final conversion of inosine to inosinic acid via the intermediate formation of hypoxanthine accounts for the net conversion of the methylated bases to inosinic acid. The utilization of the bases is sufficiently rate-limiting to cause derepression of the early enzymes required for the de novo synthesis of purine, thus accounting for the elevated accumulation of purine precursors originally observed.
Model for the Mechanism Controlling the Expression of Competent State in Pneumococcus Cultures
Authors: Tomasz Alexander
Published: January 2020

Tomasz, Alexander
(The Rockefeller University, New York, N.Y.). Model for the mechanism controlling the expression of competent state in pneumococcus cultures. J. Bacteriol.
91:
1050–1061. 1966.—The phenotypic expression of competence allowing the cells to absorb genetically active deoxyribonucleic acid molecules from their environment was examined in pneumococcal cultures growing under a variety of environmental conditions. The most important single parameter affecting the time course of this expression process was found to be the cell concentration. Constant high levels of competence could be maintained in cultures growing in a continuous-dilution device. The expression of competence seems to occur through a specific induction process “catalyzed” by a macromolecular cell product—the activator substance. Under most growth conditions, the availability of endogenous activator seems to limit the expression of competence. An “autocatalytic” production of activator ensues during the activation of cells to the competent state. Evidence is presented for physiological influences affecting the cell's capacity to react with the activator. A physiological model is proposed for the control of the competent state in pneumococcus.
Synthesis of the Enzymes of the Mandelate Pathway by
Pseudomonas putida
I. Synthesis of Enzymes by the Wild Type
Authors: Hegeman G. D.
Published: January 2020

Hegeman
, G. D. (University of California, Berkeley). Synthesis of the enzymes of the mandelate pathway by
Pseudomonas putida
. I. Synthesis of enzymes by the wild type. J. Bacteriol.
91:
1140–1154. 1966.—The control of synthesis of the five enzymes responsible for the conversion of
d
(−)-mandelate to benzoate by
Pseudomonas putida
was investigated. The first three compounds occurring in the pathway,
d
(−)-mandelate,
l
(+)-mandelate, and benzoylformate, are equipotent inducers of all five enzymes. A nonmetabolizable inducer, phenoxyacetate, also induces synthesis of these enzymes; but, unlike the metabolizable inducer-substrates, it does not elicit synthesis of enzymes that mediate steps in the pathway beyond benzoate. Under conditions of semigratuity,
dl
-mandelate elicits immediate synthesis at a steady rate of the first two enzymes of the pathway, but two enzymes which act below the level of benzoate are synthesized only after a considerable lag. Succinate and asparagine do not significantly repress the synthesis of the enzymes responsible for mandelate oxidation.
Phenomenon of Transient Repression in
Escherichia coli
Authors: Paigen Kenneth
Published: January 2020

Paigen, Kenneth
(Roswell Park Memorial Institute, Buffalo, N.Y.). Phenomenon of transient repression in
Escherichia coli
. J. Bacteriol.
91:
1201–1209. 1966.—A family of mutants has been obtained in
Escherichia coli
K-12 in which β-galactosidase is not inducible for approximately one cell generation after the cells are transferred to glucose from other carbon sources. After that period; the enzyme can be induced at the level appropriate to glucose-grown cultures of the parent cells. Among a wide variety of carbon sources, the only one capable of eliciting a state of transient repression is glucose. Conversely, transient repression occurs when cells are transferred to glucose from any of a variety of other carbon sources. The only exceptions to this so far discovered are lactose, gluconate, and xylose. Susceptibility to transient repression in mutants can also be induced in glucose-grown cells by a period of starvation. Mutant cells which have become susceptible to transient repression lose susceptibility in the presence of glucose only when they are under conditions which permit active protein synthesis. The presence of an inducer of β-galactosidase is not required during this time, nor does pre-induction for β-galactosidase diminish the susceptibility of mutants. At least two other catabolite repression-sensitive enzymes (galactokinase and tryptophanase) are also sensitive to transient repression, and the two phenomena are probably related. The absolute specificity of glucose and the pattern of response seen after growth in different carbon sources suggest that the endogenous metabolite which produces these repressions is far more readily derived from glucose in metabolism than it is from any other exogenous carbon source.
Inhibition of Enterovirus Cytopathic Effects by 2-(α-Hydroxybenzyl)-Benzimidazole
Authors: Bablanian Rostom , Eggers Hans J. , Tamm Igor
Published: January 2020

Bablanian, Rostom
(The Rockefeller University, New York, N.Y.),
Hans J. Eggers, and Igor Tamm
. Inhibition of enterovirus cytopathic effects by 2-(α-hydroxybenzyl)-benzimidazole. J. Bacteriol.
91:
1289–1294. 1966.—2-(α-Hydroxybenzyl)-benzimidazole (HBB), a specific inhibitor of enterovirus multiplication, markedly delayed the development of cytopathological changes induced by echovirus 12 or coxsackievirus B4 in monkey kidney cells, but did not prevent the ultimate degeneration of infected cells, even though virus multiplication was inhibited. The study of the development of viral cytopathic effects was facilitated by the use of antiviral immune serum, which restricted the infection to those cells which became infected by the inoculated virus and thereby established single-cycle conditions. With echovirus 12 and coxsackievirus B4 not all cells could be infected initially, even when cultures were inoculated at input multiplicities in excess of 100 plaque-forming units per cell.
Loss and Repair of Conjugal Fertility and Infectivity of the Resistance Factor and Sex Factor in
Escherichia coli
Authors: Hirota Yukinori , Fujii Toshio , Nishimura Yukinobu
Published: January 2020

Hirota, Yukinori
(University of Osaka, Osaka, Japan),
Toshio Fujii, and Yukinobu Nishimura
. Loss and repair of conjugal fertility and infectivity of the resistance factor and sex factor in
Escherichia coli
. J. Bacteriol.
91:
1298–1304. 1966.—The drug-resistance factor, R, and the sex factor, F, have homologous traits, including contagious transmission, mediation of sexuality of the host cell, and autonomous replication in their host bacteria. Cooperation between F and R factors was found with a mutant R factor, which is nontransmissible in F
−
bacteria, becoming transmissible when introduced into bacteria carrying F. Conversely, the chromosome of a sterile male strain carrying the mutant sex factor, F
r
, becomes transmissible when an R factor is introduced into the cell. The genetic determinants of R factors have been analyzed by isolation of mutant R factors, by sexual conjugation of the host bacteria, and by transduction of R factors with phage P1kc. The fertility determinant of the R factor,
m
, is inseparable from the determinant for its infectivity, but can be separated from the loci for autonomous replication of the R factor. R and F thus carry genetic determinants governing the same functions.
A Bacteriophage for
Myxococcus xanthus
: Isolation, Characterization and Relation of Infectivity to Host Morphogenesis
Authors: Burchard Robert P. , Dworkin Martin
Published: January 2020

Burchard, Robert
P. (University of Minnesota, Minneapolis),
and M. Dworkin
. A bacteriophage for
Myxococcus xanthus
: isolation, characterization and relation of infectivity to host morphogenesis. J. Bacteriol.
91:
1305–1313. 1966.—A bacteriophage (MX-1) infecting
Myxococcus xanthus
FB
t
has been isolated from cow dung. The bacteriophage particle is approximately 175 mμ long. A tail about 100 mμ in length is encased in a contractile sheath and terminates in a tail plate. The head is polyhedral with a width of about 75 mμ. The nucleic acid of the bacteriophage is deoxyribonucleic acid and has a guanine plus cytosine content of 55.5%. The bacteriophage requires 10
−3
m
Ca
++
and 10
−2
m
monovalent cation for optimal adsorption. Grown on vegetative cells of
M. xanthus
FB
t
at 30 C in 2% Casitone medium, the bacteriophage has a latent period of 120 min and a burst size of approximately 100. Host range studies indicate that three strains of
M. xanthus
including a morphogenetic mutant are sensitive to the bacteriophage, whereas
M. fulvus, Cytophaga, Sporocytophaga myxococcoides
, and a fourth strain of
M. xanthus
are not. Of the two cellular forms characteristic of the
Myxococcus
life cycle, the bacteriophage infect only the vegetative cells; they do not adsorb to microcysts. Ability to adsorb bacteriophage is lost between 65 and 75 min after initiation of the relatively synchronous conversion of vegetative cells to microcysts. The bacteriophage does not adsorb to spheroplasts. After the appearance of visible morphogenesis and before the loss of bacteriophage receptor sites, addition of bacteriophage results in the formation of microcysts which give rise to infective centers only upon germination. The possibility that the infected microcysts are harboring intact bacteriophages has been eliminated.
Isolation of
Candida
Protoplasts from a Case of
Candida
Endocarditis
Authors: Rosner Richard
Published: January 2020

Rosner, Richard
(St. Joseph's Hospital, Paterson, N.J.). Isolation of
Candida
protoplasts from a case of
Candida
endocarditis. J. Bacteriol.
91:
1320–1326. 1966.—A case of endocarditis caused by
Candida tropicalis
is described. Even though the patient was receiving adequate therapy, and all routine blood cultures were negative for growth, the patient continued to give clinical evidence of active, progressive endocarditis. The isolation of osmotically fragile bodies from blood cultures placed in an osmotically controlled medium is described in detail. The role of these bodies, called protoplasts, in the active disease process of this patient is discussed in relation to the criteria for the implication of protoplasts in the disease process. Several explanations as to what caused the in vivo formation of protoplasts of
C. tropicalis
in this patient are discussed.
Color of Cultures of
Staphylococcus epidermidis
Determined by Spectral Reflectance Colorimetry
Authors: Brown Richard W.
Published: January 2020

Brown, Richard
W. (National Animal Disease Laboratory, Ames, Iowa). Color of cultures of
Staphylococcus epidermidis
determined by spectral reflectance colorimetry. J. Bacteriol.
91:
911–918. 1966.—A colorimeter with a reflectance attachment was used to study pigment production by
Staphylococcus epidermidis
strains grown on a medium containing Trypticase Soy Agar (BBL) and cream. The color of each culture was first characterized by reflectance colorimetry for dominant wavelength, purity, and luminous reflectance (
Y
) and was then classified visually into 1 of 10 color grades. There was not complete agreement in grading colors by the two methods, inasmuch as cultures that were considered more pigmented in relation to other cultures by the reflectance method were sometimes graded visually as less pigmented, and vice versa. Nevertheless, when the cultures were visually graded as being more pigmented, there was a concomitant increase in the average values of dominant wavelength and purity with a decrease in
Y
for the cultures in each higher grade. Thus, the nonpigmented cultures had the lowest dominant wavelength and purity values but the highest
Y
(brightness) values, whereas the most pigmented cultures had the highest dominant wavelength and purity values, but the lowest
Y
values. These results indicated that the cultures did not produce pigments of different hues (greenish-yellow, yellow, yellowish-orange) each with high, medium, and low degrees of purity and brightness. The value (
1 − z
), where the chromaticity coordinate
z = Z
/(
X + Y + Z
), was found to be proportional to the purity value. An inverse relationship between the tristimulus
Z
and purity values was also demonstrated. All cultures tested by the reflectance method were also classified according to the type of spectral absorption curve obtained with pigments extracted from the cultures with methanol. A comparison of these methods indicated that determining the type of spectral absorption curve would be better for differentiating strains of
S. epidermidis
, whereas the use of the reflectance method would be better for determining differences of pigment production within strains.
Clostridium botulinum
Type E in Fish from the Great Lakes
Authors: Bott Thomas L. , Deffner Janet S. , McCoy Elizabeth , Foster E. M.
Published: January 2020

Bott, Thomas
L. (University of Wisconsin, Madison),
Janet S. Deffner, Elizabeth McCoy, and E. M. Foster
.
Clostridium botulinum
type E in fish from the Great Lakes. J. Bacteriol.
91:
919–924. 1966.—The intestinal contents of more than 3,000 fish from Lakes Erie, Superior, Huron, and Michigan were examined for
Clostridium botulinum
type E. Demonstration of the organism was accomplished by identifying its toxin in liquid cultures inoculated with material from the alimentary tract. Incidence figures, expressed as per cent of the fish tested, were: Lake Erie, 1%; Lake Superior, 1%; Lake Huron, 4%; the main body of Lake Michigan, 9%; and Green Bay (on Lake Michigan), 57%. Thus,
C. botulinum
type E appears to be widely but unevenly distributed in the Great Lakes, and fish from all areas are potential carriers of it.
Effect of 3% Hydrogen Peroxide on the Viability of
Serratia marcescens
Authors: Campbell Jack E. , Dimmick R. L.
Published: January 2020

Campbell, Jack
E. (University of California, Berkeley),
and R. L. Dimmick
. Effect of 3% hydrogen peroxide on the viability of
Serratia marcescens
. J. Bacteriol.
91:
925–929. 1966.—Populations of
Serratia marcescens
were exposed to 3% H
2
O
2
at temperatures from 0 to 20 C. The reaction appeared to follow an Arrhenius plot, but variable numbers of diminutive colonies were found after cell numbers started to decrease. Colony numbers varied on different sampling media and increased when additional incubation was imposed. The overall reaction was sensitive to age of culture, and growth capabilities of treated samples varied with time of treatment, especially during times when no loss of viability was noted. Catalase activity per cell did not correlate with changes in sensitivity; iron added to growth medium increased catalase activity and decreased sensitivity, but not in the same manner. Although the fundamental reaction is presumably molecular in nature, present methods of viability assay measure more than single events and are not suitable for these studies.
Characterization of
Mycoplasma
Aerosols as to Viability, Particle Size, and Lethality of Ultraviolet Irradiation
Authors: Kundsin Ruth B.
Published: January 2020

Kundsin, Ruth
B. (Harvard Medical School, Boston, Mass.). Characterization of
Mycoplasma
aerosols as to viability, particle size, and lethality of ultraviolet irradiation. J.
Bacteriol
.
91:
942–944. 1966.—Viable aerosols of four strains of
Mycoplasma
:
M. hominis
II,
M. pharyngis, M. pneumoniae
, and an undetermined strain recovered from a lung at autopsy were dispersed, and the particle size was determined. The median diameter of the droplet nuclei ranged from 1.5 to 3.1 μ.
M. pharyngis
had a dieaway constant
k
of 0.008, indicating a survival potential of 6 hr from 10,000 colony-forming units at 23% relative humidity. Ultraviolet irradiation destroyed over 99% of the aerosols of all four strains concurrently with spraying. The particle size and viability of the droplet nuclei carrying
Mycoplasma
were consistent with the theory of airborne transmission of lower respiratory-tract infection.
Effect of Bile on the Action of Blood Against
Salmonella
Authors: Kaye Donald , Palmieri Michelle , Rocha Heonir
Published: January 2020

Kaye, Donald
(New York Hospital-Cornell Medical Center, New York, N.Y.),
Michelle Palmieri, and Heonir Rocha
. Effect of bile on the action of blood against
Salmonella
. J. Bacteriol.
91:
945–952. 1966.—Bile is superior to Trypticase Soy Broth (BBL) as a medium for isolation of
Salmonella
from blood. In addition to inhibitory activity against many of the common bacterial contaminants, bile has the additional advantages of a greater frequency of isolation of
Salmonella
and more rapid isolation. This study investigated the factors responsible for the superiority of bile. A 20% dilution of normal human blood in Trypticase Soy Broth was usually inhibitory or bactericidal against strains of
Salmonella
. Similarly, a 20% dilution in Trypticase Soy Broth of serum from patients with
Salmonella
bacteremia was frequently inhibitory or bactericidal for the salmonellae isolated from their blood. Bile inactivated the bactericidal activity of blood or serum by inactivating complement activity. Bile (13%) in Trypticase Soy Broth inactivated complement activity in 33% blood or serum. Although bile has anticoagulant and hemolytic effects, no evidence was found that these activities contribute to the superiority of bile over Trypticase Soy Broth as a culture medium for
Salmonella
. No evidence was found for a growth-promoting factor in bile for
Salmonella
. Bile was much more effective than 0.5 or 2.0% sodium taurocholate broth in inactivating the bactericidal activity of blood.