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Objective: Determine the impact of standardization of care and counseling on survival and morbidities of neonates born at 22-23 weeks gestation., Design: Retrospective cohort study of 244 neonates born at 22-23 weeks gestation between 2015 and 2023 in a large healthcare system. The primary outcome was survival of neonates receiving intensive care to NICU discharge. Secondary outcomes included morbidities and resource utilization., Results: Neonates born at 22-23 weeks received more intensive care after care standardization (OR 5.4 (95% CI 2.3-12.6), p < 0.0001). Survival remained stable (aOR 0.93 (95% CI 0.32-2.7), p = 0.89) despite more neonates born at 22 weeks receiving intensive care. Resource utilization remained stable., Conclusions: Standardizing counseling and care increased the provision of antenatal steroids and intensive care for neonates born at 22 weeks gestation. This allowed neonates born at 22 weeks to survive to discharge without increasing morbidity and resource utilization., Competing Interests: Competing interests: The authors declare no competing interests. Ethics approval and consent to participate: The Cincinnati Children’s Institutional Review Board Committee approved this study (IRB#2024-0228), which was granted a waiver of consent. All methods were conducted according to the institution’s relevant guidelines and regulations., (© 2025. The Author(s).)

Delirium often goes unrecognized in neonates and children because of lack of experience in evaluating behavior and cognition, insufficient awareness of the prevalence, and nondistinctive symptoms in this population. Although there are increasing reports of the presence of delirium in neonates, there are few data to guide the pharmacologic treatment in this population. In this retrospective single-center case series, we present our experience using quetiapine to treat delirium in 9 medically complex neonates. Based on an extensive literature review, expert opinion, and institutional experience, we propose an approach for monitoring and treating delirium in neonates and infants., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: The objective of this study was to identify factors birthing parents consider related to potential resuscitation of a periviable infant., Study Design: Birthing parents who received a prenatal consult from a newborn intensive care unit provider between 22.0 and 24.6 weeks gestational age were eligible to participate in a semi-structured interview focused on their periviable decision making. Interview transcripts were coded and analyzed using thematic content analysis., Result: Qualitative analysis shows that birthing parents attribute their decision to a balance between vitality and suffering, with the balance point influenced by various elements. While parents described the choice they made, none reported that the information they received during the prenatal consult had a significant impact., Conclusion: This study highlights the minimal impact that information given during a periviable consult has on parental decision making. Information from this study can be used to develop an improved model of perinatal consultation., Competing Interests: Competing interests The authors declare no competing interests. Ethics Ethics approval obtained from the Cincinnati Children’s Hospital Medical Center Institutional Review Board (2022-0080), University of Cincinnati Health Office of Clinical Research (666), and TriHealth Institutional Review Board (22-058). All research conducted was in accordance with the ethical standards of the institutional ethics committees. A waiver of written consent was granted for this study; informed consent was obtained verbally for participation from all participants., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Technological advancements before and after delivery have greatly altered the counseling of pregnant patients facing a fetal diagnosis of severe oligohydramnios or anhydramnios secondary to congenital anomalies of the kidneys and urinary tract. Once considered a nearly uniformly lethal abnormality, long-term survival may now be possible secondary to prenatal innovations aimed at restoring the amniotic fluid volume and the availability of more advanced neonatal dialysis techniques. However, these available therapies are far from perfect. The procedures are onerous for pregnant patients without a guarantee of success, and families must prepare themselves for the complex life-long medical care that will be necessary for surviving individuals. Multidisciplinary counseling is imperative to help pregnant individuals understand the complexity of these conditions and assist them in exercising their right to informed decision-making. Moreover, as with any developing field of medicine, providers must contend with ethical questions related to the treatment options, including questions regarding patient-hood, distributive justice, and the blurred lines between research, innovation, and standard care. These ethical questions are best addressed in a multidisciplinary fashion with consideration of multiple points of view from various subspecialties. Only by seeing the entirety of the picture can we hope to best counsel patients about these highly complex situations and help navigate the most appropriate care path., (Copyright © 2024 by the American Academy of Pediatrics.)

Objective: To evaluate whether racial and socioeconomic inequities in pediatric palliative care utilization extend to children with high-intensity neurologic impairment (HI-NI), which is a chronic neurological diagnosis resulting in substantial functional morbidity and mortality., Study Design: We conducted a retrospective study of patients with HI-NI who received primary care services at a tertiary care center from 2014 through 2019. HI-NI diagnoses that warranted a palliative care referral were identified by consensus of a multidisciplinary team. The outcome was referral to palliative care. The primary exposure was race, categorized as Black or non-Black to represent the impact of anti-Black racism. Additional exposures included ethnicity (Hispanic/non-Hispanic) and insurance status (Medicaid/non-Medicaid). Descriptive statistics, bivariate analyses, and multivariable logistic regression models were performed to assess associations between exposures and palliative care referral., Results: A total of 801 patients with HI-NI were included; 7.5% received a palliative referral. There were no differences in gestational age, sex, or ethnicity between patients who received a referral and those who did not. In multivariable analysis, adjusting for ethnicity, sex, gestational age, and presence of complex chronic conditions, Black children (aOR 0.47, 95% CI 0.26, 0.84) and children with Medicaid insurance (aOR 0.40, 95% CI 0.23, 0.70) each had significantly lower odds of palliative referral compared with their non-Black and non-Medicaid-insured peers, respectively., Conclusions: We identified inequities in pediatric palliative care referral among children with HI-NI by race and insurance status. Future work is needed to develop interventions, with families, aimed at promoting more equitable, antiracist systems of palliative care., Competing Interests: Declaration of Competing Interest This project was supported by funds from the Bureau of Health Professions (BHPr), Health Resources and Services Administration (HRSA), Department of Health and Human Services (DHHS), under National Research Service Award (NRSA) grant number T32HP10027, General Pediatrics Research Fellowship in Child and Adolescent Health, total award amount $2,432,131. The information or content and conclusions are those of the author and should not be construed as the official position or policy of, nor should any endorsements be inferred by the BHPr, HRSA, DHHS or the U.S. Government. The other authors declare no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Delirium often goes unrecognized in neonates and children because of lack of experience in evaluating behavior and cognition, insufficient awareness of the prevalence, and nondistinctive symptoms in this population. Although there are increasing reports of the presence of delirium in neonates, there are little data to guide the pharmacologic treatment in this population. In this retrospective single-center case series, we present our experience using quetiapine to treat delirium in 9 medically complex neonates. Based on an extensive literature review, expert opinion, and institutional experience, we propose an approach for monitoring and treating delirium in neonates and infants., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Restrictive abortion laws have impacts reaching far beyond the immediate sphere of reproductive health, with cascading effects on clinical and ethical aspects of neonatal care, as well as perinatal palliative care. These laws have the potential to alter how families and clinicians navigate prenatal and postnatal medical decisions after a complex fetal diagnosis is made. We present a hypothetical case to explore the nexus of abortion care and perinatal care of fetuses and infants with life-limiting conditions. We will highlight the potential impacts of limited abortion access on families anticipating the birth of these infants. We will also examine the legally and morally fraught gray zone of gestational viability where both abortion and resuscitation of live-born infants can potentially occur, per parental discretion. These scenarios are inexorably impacted by the rapidly changing legal landscape in the U.S., and highlight difficult ethical dilemmas which clinicians may increasingly need to navigate., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Objective: To determine levels of moral distress in a pediatric unit caring for patients with tracheostomy/ventilator dependence., Hypothesis: Moral distress will be significant in a dedicated pediatric trach/vent unit., Methods: The Moral Distress Survey-Revised (MDS-R) is a 21-question survey measuring moral distress in pediatrics. The MDS-R was anonymously distributed to medical degree/doctor of osteopathy (MD/DOs), advanced practice practitioners (APPs), registered nurses (RNs), and respiratory therapists (RTs) in a unit caring for tracheostomy/ventilator dependent patients. Descriptive statistics, bivariate and multivariate analysis were performed., Results: Response rate was 48% (61/127). Mean MDS-R score was 83 (range 43-119), which is comparable to reported levels in the pediatric intensive care unit (ICU). APPs had the highest median rate of moral distress (112, interquartile range [IQR], 72-138), while MD/DOs had the lowest median score (49, IQR, 43-77). RNs and RTs had MDS-R scores between these two groups (medians of 91 and 84, respectively)., Conclusions: Moral distress levels in a unit caring for long term tracheostomy and ventilator dependent patients are high, comparable to levels in pediatric ICUs. APPs. APPs had higher levels of distress compared to other groups. This may be attributable to the constant stressors of being the primary provider for complex patients, especially in a high-volume inpatient setting., (© 2024 Wiley Periodicals LLC.)

The Supreme Court ruling in Dobbs v. Jackson Women's Health Organization has far-reaching implications that go beyond the practice of obstetrics and gynecology. The ruling and subsequent laws and bills impact many specialties and have implications for healthcare as a whole. The rapidly changing medicolegal landscape has significant bearings on and implications for the fields of neonatology and pediatrics. These rulings have an impact on the patient-physician relationship and a shared decision-making approach to care. Furthermore, there are significant sequelae of forced birth and resuscitation. This review provides a clinically relevant update of the current medicolegal landscape and applications to the practice of neonatology., (© 2022. The Author(s).)

Fetal neurology is a rapidly evolving and expanding field. Discussions about diagnosis, prognosis, treatment options, and goals of care often begin in the antenatal period. However, there are inherent challenges to fetal counseling of neurological diagnoses due to limitations of fetal imaging, prognostic uncertainty, and variability in neurodevelopmental outcomes. In the midst of uncertainty, families are challenged with preparing a care plan for their baby while simultaneously experiencing profound grief. The paradigms of perinatal palliative care can assist with the grieving process and help frame diagnostic testing and complex decision-making within the context of a family's spiritual, cultural, and social belief system. This ultimately leads to a shared decision-making process and value driven medical care. While perinatal palliative care programs have expanded, many families faced with such diagnoses never meet with a palliative care team prior to delivery. Moreover, there is significant variability in the availability of palliative care services throughout the country. Using an illustrative vignette of a patient with a prenatally diagnosed encephalocele, this review aims to provide a basic framework of perinatal palliative care for fetal neurology diagnoses that emphasizes 1) importance of clear, consistent, and transparent communication among all subspecialists and families, 2) creation of a palliative care birth plan, 3) importance of consistent care providers and longitudinal points of contact prenatally and post-delivery, 4) close communication between the prenatal and post-natal providers to allow for optimal continuity of care, and 5) recognize that information, care plans, and goals of care often evolve over time., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Cortezzo, Vawter-Lee, Shoaib and Venkatesan.)

Ryanodine receptor type 1-related disorder (RYR1-RD) is the most common subgroup of congenital myopathies with a wide phenotypic spectrum ranging from mild hypotonia to lethal fetal akinesia. Genetic testing for myopathies is imperative as the diagnosis informs counseling regarding prognosis and recurrence risk, treatment options, monitoring, and clinical management. However, diagnostic challenges exist as current options are limited to clinical suspicion prompting testing including: single gene sequencing or familial variant testing, multi-gene panels, exome, genome sequencing, and invasive testing including muscle biopsy. The timing of diagnosis is of great importance due to the association of RYR1-RD with malignant hyperthermia (MH). MH is a hypermetabolic crisis that occurs secondary to excessive calcium release in muscles, leading to systemic effects that can progress to shock and death if unrecognized. Given the association of MH with pathogenic variants in RYR1, a diagnosis of RYR1-RD necessitates an awareness of medical team to avoid potentially triggering agents. We describe a case of a unique fetal presentation with bilateral diaphragmatic eventrations who had respiratory failure, dysmorphic facial features, and profound global hypotonia in the neonatal period. The diagnosis was made at several months of age, had direct implications on her clinical care related to anticipated need to long-term ventilator support, and ultimately death secondary an arrhythmia as a result of suspected MH. Our report reinforces the importance of having high suspicion for a genetic syndrome and pursuing early, rapid exome or genome sequencing as first line testing in critically ill neonatal intensive care unit patients and further evaluating the pathogenicity of a variant of uncertain significance in the setting of a myopathic phenotype., (© 2023 The Authors. American Journal of Medical Genetics Part A published by Wiley Periodicals LLC.)

Medically complex infants are experiencing longer hospital stays, more invasive procedures, and increasingly involved therapeutic interventions that often require long-term analgesia and sedation. This is most commonly achieved with continuous intravenous infusions of opioids and benzodiazepines. There are times when patients develop a tolerance for these medications or the clinical scenario necessitates a rapid wean of them. A rapid wean of either class of medication can lead to increased signs of pain and agitation or withdrawal symptoms. As a result, when a rapid wean is needed or there has been a failure to control symptoms with conventional measures, alternative therapies are considered. Propofol, a sedative hypnotic typically used for general anesthesia and procedural sedation, is one such medication. It has effectively been used for short-term sedation in adults and children to facilitate weaning benzodiazepines and opioids. There is a paucity of data on the use of propofol in infants for this purpose. Here we describe the use of propofol to rapidly wean high-dose sedation and analgesia medications, a propofol sedation washout, in 3 infants. The washouts proved to be safe and efficacious. Based on institutional experience and a literature review, considerations and recommendations are made for propofol sedation washouts in infants., Competing Interests: Disclosure. The authors declare no conflicts or financial interest in any product or service mentioned in the manuscript, including grants, equipment, medications, employment, gifts, and honoraria. The authors had full access to all patient information in this report and take responsibility for the integrity and accuracy of the report., (Copyright. Pediatric Pharmacy Association. All rights reserved. For permissions, email: membership@pediatricpharmacy.org.)

Objectives: To identify factors associated with prenatal, perinatal, and postnatal outcomes, and determine medical care use for fetuses and infants with trisomy 13 (T13) and trisomy 18 (T18)., Study Design: This population-based retrospective cohort study included all prenatal and postnatal diagnoses of T13 or T18 in the greater Cincinnati area from January 1, 2012, to December 31, 2018. Overall survival, survival to hospital discharge, medical management, and maternal, fetal, and neonatal characteristics are analyzed., Results: There were 124 pregnancies (125 fetuses) that were identified, which resulted in 72 liveborn infants. Male fetal sex and hydrops were associated with a higher rate of spontaneous loss. The median length of survival was 7 and 29 days, for infants with T13 and T18, respectively. Of the 27 infants alive at 1 month of age, 13 (48%) were alive at 1 year of age. Only trisomy type (T13), goals of care (comfort care), and extremely low birthweight were associated with a shorter length of survival. A high degree of variability existed in the use of medical services, with 28% of infants undergoing at least 1 surgical procedure and some children requiring repeated (≤29) or prolonged (>1 year) hospitalizations., Conclusions: Although many infants with T13 or T18 did not survive past the first week of life, nearly 20% lived for more than 1 year with varying degrees of medical support. The length of survival for an infant cannot be easily predicted, and surviving infants have high health care use throughout their lifespans., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Purpose of review: Despite advances in technology and treatment options, over 15,000 neonates die each year in the United States. The majority of the deaths, with some estimates as high as 80%, are the result of a planned redirection of care or comfort measures only approach to care. When curative or life-prolonging interventions are not available or have been exhausted, parents focus on preserving quality of life and eliminating needless suffering. Parents hope their child will have a peaceful death and will not feel pain. A significant component of end-of-life care is high quality symptom evaluation and management. It is important that neonatal providers are knowledgeable in symptom management to address common sources of suffering and distress for babies and their families at the end-of-life (EOL). Recent findings: Medically complex neonates with life-threatening conditions are a unique patient population and there is little research on end-of-life symptom assessment and management. While there are tools available to assess symptoms for adolescents and adults, there is not a recognized set of tools for the neonatal population. Nonetheless, it is widely accepted that neonates experience significant symptoms at end-of-life. Most commonly acknowledged manifestations are pain, dyspnea, agitation, and secretions. In the absence of data and established guidelines, there is variability in their clinical management. This contributes to provider discomfort and inadequate symptom control. Summary: End-of-life symptom assessment and management is an important component of neonatal end-of-life care. While there remains a paucity of studies and data, it is prudent that providers adequately manage symptoms. Likewise, it is important that providers are educated so that they can effectively guide families through the dying process by discussing disease progression, physical changes, and providing empathetic support. In this review, the authors make recommendations for non-pharmacological and pharmacological management of end-of-life symptoms in neonates., (Copyright © 2020 Cortezzo and Meyer.)

Moral distress is prevalent in the neonatal intensive care unit (NICU), where decisions regarding end-of-life care, periviable resuscitation, and medical futility are common. Due to its origins in the nursing literature, moral distress has primarily been reported among bedside nurses in relation to the hierarchy of the medical team. However, it is increasingly recognized that moral distress may exist in different forms than initially described and that healthcare professions outside of nursing experience it. Advances in medical technology have allowed the smallest, sickest neonates to survive. The treatment for critically ill infants is no longer simply limited by the capability of medical technology but also by moral and ethical boundaries of what is right for a given child and family. Shared decision-making and the zone of parental discretion can inform and challenge the medical team to balance the complexities of patient autonomy against harm and suffering. Limited ability to prognosticate and uncertainty in outcomes add to the challenges faced with ethical dilemmas. While this does not necessarily equate to moral distress, subjective views of quality of life and personal values in these situations can lead to moral distress if the plans of care and the validity of each path are not fully explored. Differences in opinions and approaches between members of the medical team can strain relationships and affect each individual differently. It is unclear how the various types of moral distress uniquely impact each profession and their role in the distinctively challenging decisions made in the NICU environment. The purpose of this review is to describe moral distress and the situations that give rise to it in the NICU, ways in which various members of the medical team experience it, how it impacts care delivery, and approaches to address it., (Copyright © 2020 Mills and Cortezzo.)

Purpose of Review: A significant number of pregnancies are complicated by a fetus with a life-limiting diagnosis. As diagnoses are made earlier in the pregnancy, families experience anticipatory grief and are faced with navigating goals of care for a baby that has yet to be born. With the support of the care team, families can begin to grieve, plan, and make meaningful memories during the duration of the pregnancy, the birth of their baby, and life of the child. Creating a palliative care birth plan, which expands beyond the traditional concept for delivery planning to include prenatal, perinatal, and neonatal care has become an important method for parents to process the diagnosis, for parents to document their wishes, and for members of the care team to communicate with the goal of supporting and enhancing the experience of the family. This articles reviews recent and relevant literature on the importance of birth planning and the role of perinatal palliative care when a life-limiting fetal diagnosis is made. Recent Findings: The process of birth planning is an important component of perinatal palliative care. Through this process, families can express their fears, values, hopes, and wishes. It also offers an opportunity for providers to communicate these wishes for the remainder of the pregnancy, the delivery, birth, and time afterwards. This has been demonstrated to decrease maternal stress and promote family centered care. Summary: Perinatal birth planning is an important component of perinatal palliative care when a fetus has a life-limiting diagnosis. The process of birth planning can be supportive and therapeutic as well as an important communication tool. With multiple practices and designs of perinatal palliative care programs, there are no standard tools even though important components have been identified. Ultimately, the strategies outlined here can be used as advance care planning tools., (Copyright © 2020 Cortezzo, Ellis and Schlegel.)

Morphine is the opioid most commonly used for neonatal pain management. In intravenous form, it is administered as continuous infusions and intermittent injections, mostly based on empirically established protocols. Inadequate pain control in neonates can cause long-term adverse consequences; however, providing appropriate individualized morphine dosing is particularly challenging due to the interplay of rapid natural physiological changes and multiple life-sustaining procedures in patients who cannot describe their symptoms. At most institutions, morphine dosing in neonates is largely carried out as an iterative process using a wide range of starting doses and then titrating to effect based on clinical response and side effects using pain scores and levels of sedation. Our background data show that neonates exhibit large variability in morphine clearance resulting in a wide range of exposures, which are poorly predicted by dose alone. Here, we describe the development and implementation of an electronic health record-integrated, model-informed decision support platform for the precision dosing of morphine in the management of neonatal pain. The platform supports pharmacokinetic model-informed dosing guidance and has functionality to incorporate real-time drug concentration information. The feedback is inserted directly into prescribers' workflows so that they can make data-informed decisions. The expected outcomes are better clinical efficacy and safety with fewer side effects in the neonatal population., (© 2019 The Authors Clinical Pharmacology & Therapeutics © 2019 American Society for Clinical Pharmacology and Therapeutics.)

Background: Providers often use birth plans to document parents' wishes for their fetus with a life-limiting condition. Objective: The objective of the study was to (1) discover important components of a birth plan for parents and providers who carry them out, and (2) understand the experience of parents and providers with birth plans. Methods: The study design involves mixed-methods, descriptive, exploratory survey. This involves parents ( n  = 20) of a pregnancy complicated by a life-limiting diagnosis and providers who care for them ( n  = 116). The approach involves descriptive and univariate analyses for quantitative data and thematic analysis for qualitative data. Results: Consistent components for families and physicians were diagnosis and medical management of the infant. Families gave greater emphasis on memory-making preferences. Parents feel birth plans give them a sense of control. Themes emerged from parents' experience of creating a birth plan are as follows: sense of control, therapeutic, memory making, effective communication, feeling prepared, and unexpected events. Most physicians feel comfortable discussing goals of care with families but report insufficient time. The importance of components of birth plans and perception of the parents' understanding of the prognosis varied by specialty. Discussion: Birth plans are beneficial and provide a greater sense of control for parents. Most physicians feel comfortable utilizing them. More than one-third of the physicians do not feel that they have time to complete a birth plan with parents. Communication between physicians and families about limitations of the plan and the potential trajectories could be improved. Communication between maternal and neonatal care providers regarding parent expectations and understanding could also be improved.

Atypical twinning highlights that complex mechanisms responsible for twinning are not fully understood and may give further insight into the mechanisms involved. To assume that phenotypic difference is the result of dizygotic twinning would be erroneous and could have significant implications in the care and counseling provided to these patients., Competing Interests: None declared.

Objective: The aim of the study is to determine the perceptions of end-of-life care practices and experience with infants who have died in the NICU among neonatologists, advanced practitioners, nurses, and parents, and also to determine perceived areas for improvement and the perceived value of a palliative care team., Study Design: This descriptive, exploratory cross-sectional study using surveys consisting of 7-point Likert scales and free response comments was sent to all neonatologists (n = 14), advanced practitioners (n = 40), and nurses (n = 184) at Connecticut Children's Medical Center's neonatal intensive care units (NICUs) in April 2013 and to all parents whose infants died in these NICUs from July 1, 2011, to December 31, 2012 (n = 28)., Results: The response rates were 64.3% for physicians; 50.0% for practitioners; 40.8% for nurses; and 30.4% for parents. Most providers reported they feel comfortable delivering end-of-life care. Bereavement support, debriefing/closure conferences, and education did not occur routinely. Families stressed the importance of memory making and bereavement/follow-up. Consistent themes of free responses include modalities for improving end-of-life care, inconsistency of care delivery among providers, and the importance of memory making and follow-up., Conclusion: End-of-life experiences in the NICU were perceived as variable and end-of-life practices were, at times, perceived as inconsistent among providers. There are areas for improvement, and participants reported that a formalized palliative care team could help. Families desire memory making, follow-up, and bereavement support., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Objective: Determine palliative and end-of-life care practices, barriers and beliefs among US neonatologists, and relationships between practice characteristics and palliative care delivery., Study Design: A descriptive cross-sectional survey with ordinal measurements. The survey was sent to 1885 neonatologists., Results: There were 725 responses (38.5%) with 653 (34.6%) completing the survey. Of those, 58.0% (n=379) have palliative care teams and 72.0% (n=470) have staff support groups or bereavement services. Palliative care education was deemed important (n=623) and needed. Barriers include emotional difficulties, staff disagreements and difficulty forming palliative care teams. Palliative care teams or staff bereavement groups were significantly predictive of willingness to initiate palliative care and more positive views or experiences., Conclusion: Neonatologists believe that palliative care is important. Education and palliative care teams help provide quality care. Exploration of differing views of palliative care among team members is needed.

Aims: To elucidate the factors that determine the rate of germination of Bacillus subtilis spores with very high pressure (VHP) and the mechanism of VHP germination., Methods and Results: Spores of B. subtilis were germinated rapidly with a VHP of 500 MPa at 50 degrees C. This VHP germination did not require the spore's nutrient-germinant receptors, as found previously, and did not require diacylglycerylation of membrane proteins. However, the spore's pool of dipicolinic acid (DPA) was essential. Either of the two redundant enzymes that degrade the spore's peptidoglycan cortex, and thus allow completion of spore germination, was essential for completion of VHP germination. However, neither of these enzymes was needed for DPA release triggered by VHP treatment. Completion of spore germination as well as DPA release with VHP had an optimum temperature of approx. 60 degrees C, in contrast to an optimum temperature of 40 degrees C for germination with the moderately high pressure of 150 MPa. The rate of spore germination by VHP decreased approx. fourfold when the sporulation temperature increased from 23 degrees C to 44 degrees C, and decreased twofold when 1 mol l(-1) salt was present in sporulation. However, large variations in levels of unsaturated fatty acids in the spore's inner membranes did not affect rates of VHP germination. Complete germination of spores by VHP was not inhibited significantly by killing of spores with several oxidizing agents, and was not inhibited by ethanol, octanol or o-chlorophenol at concentrations that abolish nutrient germination. Completion of spore germination by VHP was also inhibited by Hg(2+), but this ion did not inhibit DPA release caused by VHP. In contrast, dodecylamine, a surfactant that can trigger spore germination, strongly inhibited DPA release caused by VHP treatment., Conclusions: VHP does not cause spore germination by acting upon the spore's nutrient-germinant receptors, but by directly causing DPA release. This DPA release then leads to subsequent completion of germination. VHP likely acts on the spore's inner membrane to cause DPA release, targeting either a membrane protein or the membrane itself. However, the precise identity of this target is not yet clear., Significance and Impact of the Study: There is significant interest in the use of VHP to eliminate or reduce levels of bacterial spores in foods. As at least partial spore germination by pressure is almost certainly essential for subsequent spore killing, knowledge of factors involved and the mechanism of VHP germination are crucial to the understanding of spore killing by VHP. This work provides new insight into factors that can affect the rate of B. subtilis spore germination by VHP, and into the mechanism of VHP germination itself.

The GerA nutrient receptor alone triggers germination of Bacillus subtilis spores with L-alanine or L-valine, and these germinations were stimulated by glucose and K+ plus the GerK nutrient receptor. The GerB nutrient receptor alone did not trigger spore germination with any nutrients but required glucose, fructose, and K+ (GFK) (termed cogerminants) plus GerK for triggering of germination with a number of L-amino acids. GerB and GerA also triggered spore germination cooperatively with l-asparagine, fructose, and K+ and either L-alanine or L-valine. Two GerB variants (termed GerB*s) that were previously isolated by their ability to trigger spore germination in response to D-alanine do not respond to D-alanine but respond to the same L-amino acids that stimulate germination via GerB plus GerK and GFK. GerB*s alone triggered spore germination with these L-amino acids, although GerK plus GFK stimulated the rates of these germinations. In contrast to l-alanine germination via GerA, spore germination via L-alanine and GerB or GerB* was not inhibited by D-alanine. These data support the following conclusions. (i) Interaction with GerK, glucose, and K+ somehow stimulates spore germination via GerA. (ii) GerB can bind and respond to L-amino acids, although normally either the binding site is inaccessible or its occupation is not sufficient to trigger spore germination. (iii) Interaction of GerB with GerK and GFK allows GerB to bind or respond to amino acids. (iv) In addition to spore germination due to the interaction between GerA and GerK, and GerB and GerK, GerB can interact with GerA to trigger spore germination in response to appropriate nutrients. (v) The amino acid sequence changes in GerB*s reduce these receptor variants' requirement for GerK and cogerminants in their response to L-amino acids. (vi) GerK binds glucose, GerB interacts with fructose in addition to L-amino acids, and GerA interacts only with L-valine, L-alanine, and its analogs. (vii) The amino acid binding sites in GerA and GerB are different, even though both respond to L-alanine. These new conclusions are integrated into models for the signal transduction pathways that initiate spore germination.

Different nutrient receptors varied in triggering germination of Bacillus subtilis spores with a pressure of 150 MPa, the GerA receptor being more responsive than the GerB receptor and even more responsive than the GerK receptor. This hierarchy in receptor responsiveness to pressure was the same as receptor responsiveness to a mixture of nutrients. The levels of nutrient receptors influenced rates of pressure germination, since the GerA receptor is more abundant than the GerB receptor and elevated levels of individual receptors increased spore germination by 150 MPa of pressure. However, GerB receptor variants with relaxed specificity for nutrient germinants responded as well as the GerA receptor to this pressure. Spores lacking dipicolinic acid did not germinate with this pressure, and pressure activation of the GerA receptor required covalent addition of diacylglycerol. However, pressure activation of the GerB and GerK receptors displayed only a partial (GerB) or no (GerK) diacylglycerylation requirement. These effects of receptor diacylglycerylation on pressure germination are similar to those on nutrient germination. Wild-type spores prepared at higher temperatures germinated more rapidly with a pressure of 150 MPa than spores prepared at lower temperatures; this was also true for spores with only one receptor, but receptor levels did not increase in spores made at higher temperatures. Changes in inner membrane unsaturated fatty acid levels, lethal treatment with oxidizing agents, or exposure to chemicals that inhibit nutrient germination had no major effect on spore germination by 150 MPa of pressure, except for strong inhibition by HgCl2.

Aims: To elucidate factors influencing the sensitivity of Bacillus subtilis spores to DNA damaging chemicals., Methods and Results: Wild-type spores of B. subtilis made at lower temperatures were more sensitive to the DNA damaging chemicals formaldehyde and nitrous acid than were spores made at higher temperatures, but this was not the case with the DNA alkylating agents ethylmethanesulphonate and methylmethanesulphonate. Spores lacking most DNA protective alpha/beta-type small, acid-soluble proteins (termed alpha-beta- spores) made at lower temperatures were also more sensitive to killing through DNA damage by hydrogen peroxide than were alpha-beta- spores made at higher temperatures. The spore coat, whose composition varies significantly with sporulation temperature, played only a minor role in spore resistance to these DNA damaging agents. Spores made at lower temperatures exhibited higher permeability to the methylamine and germinated more rapidly with the surfactant dodecylamine than did spores made at higher temperatures. Treatment of spores with the oxidizing agent cumene hydroperoxide sensitized the surviving spores to all these DNA damaging agents. The fatty acid composition of the inner membrane of spores made at different temperatures differed significantly, but levels of unsaturated fatty acids in the inner membrane did not influence spore resistance to DNA damaging agents or the sensitization to such agents by prior treatment with cumene hydroperoxide., Conclusions: The higher rates of methylamine permeation across the inner membrane of spores made at lower temperatures and the greater sensitivity of wild-type spores made at lower temperatures to formaldehyde and nitrous acid and of alpha-beta- spores made at lower temperatures to hydrogen peroxide, all agents that must pass through the spore's inner membrane to damage DNA in the spore core, suggest that the permeability of the inner membrane is a significant factor influencing spore sensitivity to these agents. The sensitization of spores to DNA damaging chemicals by pretreatment with an oxidizing agent, a treatment that increases the permeability of the spore's inner membrane, and the more rapid dodecylamine germination of spores made at lower temperatures are consistent with this suggestion., Significance and Impact of the Study: The results in this communication provide new insight into the factors that influence the resistance of spores of Bacillus species to chemicals that kill spores by damaging spore DNA.

In Tetrahymena thermophila, an "antisense ribosome" technology has been developed for inhibiting gene expression and generating novel mutants. Short segments of genes are inserted in antisense orientation into an rDNA vector in a region corresponding to an external loop of the folded rRNA. DNA segments derived from the 5'-ends of genes have proven most effective in reducing cognate gene expression. To investigate the efficacy of other genic regions, we generated Tetrahymena cell lines with antisense ribosome constructs containing 100-bp DNA segments derived from the 5'-ends, 3'-ends, and internal coding regions of two non-essential genes, granule lattice protein 1 and macronuclear histone H1. The 5'- and 3'-end constructs inhibited gene expression, but antisense ribosomes derived exclusively from coding regions had little effect.

Aims: To determine if treatment of Bacillus subtilis spores with a variety of oxidizing agents causes damage to the spore's inner membrane., Methods and Results: Spores of B. subtilis were killed 80-99% with wet heat or a variety of oxidizing agents, including betadine, chlorine dioxide, cumene hydroperoxide, hydrogen peroxide, Oxone, ozone, sodium hypochlorite and t-butylhydroperoxide, and the agents neutralized and/or removed. Survivors of spores pretreated with oxidizing agents exhibited increased sensitivity to killing by a normally minimal lethal heat treatment, while spores pretreated with wet heat did not. In addition, spores treated with wet heat or the oxidizing agents, except sodium hypochlorite, were more sensitive to high NaCl in plating media than were untreated spores. The core region of spores treated with at least two oxidizing agents was also penetrated much more readily by methylamine than was the core of untreated spores, and spores treated with oxidizing agents but not wet heat germinated faster with dodecylamine than did untreated spores. Spores of strains with very different levels of unsaturated fatty acids in their inner membrane exhibited essentially identical resistance to oxidizing agents., Conclusions: Treatment of spores with oxidizing agents has been suggested to cause damage to the spore's inner membrane, a membrane whose integrity is essential for spore viability. The sensitization of spores to killing by heat and to high salt after pretreatment with oxidizing agents is consistent with and supports this suggestion. Presumably mild pretreatment with oxidizing agents causes some damage to the spore's inner membrane. While this damage may not be lethal under normal conditions, the damaged inner membrane may be less able to maintain its integrity, when dormant spores are exposed to high temperature or when germinated spores are faced with osmotic stress. Triggering of spore germination by dodecylamine likely involves action by this agent on the spore's inner membrane allowing release of the spore core's depot of dipicolinic acid. Presumably dodecylamine more readily alters the permeability of a damaged inner membrane and thus more readily triggers germination of spores pretreated with oxidizing agents. Damage to the inner spore membrane by oxidizing agents is also consistent with the more rapid penetration of methylamine into the core of treated spores, as the inner membrane is likely the crucial permeability barrier to methylamine entry into the spore core. As spores of strains with very different levels of unsaturated fatty acids in their inner membrane exhibited essentially identical resistance to oxidizing agents, it is not through oxidation of unsaturated fatty acids that oxidizing agents kill and/or damage spores. Perhaps these agents work by causing oxidative damage to key proteins in the spore's inner membrane., Significance and Impact of the Study: The more rapid heat killing and germination with dodecylamine, the greater permeability of the spore core and the osmotic stress sensitivity in outgrowth of spores pretreated with oxidizing agents is consistent with such agents causing damage to the spore's inner membrane, even if this damage is not lethal under normal conditions. It may be possible to take advantage of this phenomenon to devise improved, less costly regimens for spore inactivation.

Aims: To determine the mechanism of action of inhibitors of the germination of spores of Bacillus species, and where these inhibitors act in the germination process., Methods and Results: Spores of various Bacillus species are significant agents of food spoilage and food-borne disease, and inhibition of spore germination is a potential means of reducing such problems. Germination of the following spores was studied: (i) wild-type B. subtilis spores; (ii) B. subtilis spores with a nutrient receptor variant allowing recognition of a novel germinant; (iii) B. subtilis spores with elevated levels of either the variant nutrient receptor or its wild-type allele; (iv) B. subtilis spores lacking all nutrient receptors and (v) wild-type B. megaterium spores. Spores were germinated with a variety of nutrient germinants, Ca2+-dipicolinic acid (DPA) and dodecylamine for B. subtilis spores, and KBr for B. megaterium spores. Compounds tested as inhibitors of germination included alkyl alcohols, a phenol derivative, a fatty acid, ion channel blockers, enzyme inhibitors and several other compounds. Assays used to assess rates of spore germination monitored: (i) the fall in optical density at 600 nm of spore suspensions; (ii) the release of the dormant spore's large depot of DPA; (iii) hydrolysis of the dormant spore's peptidoglycan cortex and (iv) generation of CFU from spores that lacked all nutrient receptors. The results with B. subtilis spores allowed the assignment of inhibitory compounds into two general groups: (i) those that inhibited the action of, or response to, one nutrient receptor and (ii) those that blocked the action of, or response to, several or all of the nutrient receptors. Some of the compounds in groups 1 and 2 also blocked action of at least one cortex lytic enzyme, however, this does not appear to be the primary site of their action in inhibiting spore germination. The inhibitors had rather different effects on germination of B. subtilis spores with nutrients or non-nutrients, consistent with previous work indicating that germination of B. subtilis spores by non-nutrients does not involve the spore's nutrient receptors. In particular, none of the compounds tested inhibited spore germination with dodecylamine, and only three compounds inhibited Ca2+-DPA germination. In contrast, all compounds had very similar effects on the germination of B. megaterium spores with either glucose or KBr. The effects of the inhibitors tested on spores of both Bacillus species were largely reversible., Conclusions: This work indicates that inhibitors of B. subtilis spore germination fall into two classes: (i) compounds (most alkyl alcohols, N-ethylmaleimide, nifedipine, phenols, potassium sorbate) that inhibit the action of, or response to, primarily one nutrient receptor and (ii) compounds [amiloride, HgCl2, octanoic acid, octanol, phenylmethylsulphonylfluoride (PMSF), quinine, tetracaine, tosyl-l-arginine methyl ester, trifluoperazine] that inhibit the action of, or response to, several nutrient receptors. Action of these inhibitors, is reversible. The similar effects of inhibitors on B. megaterium spore germination by glucose or KBr indicate that inorganic salts likely trigger germination by activating one or more nutrient receptors. The lack of effect of all inhibitors on dodecylamine germination suggests that this compound stimulates germination by creating channels in the spore's inner membrane allowing DPA release., Significance and Impact of the Study: This work provides new insight into the steps in spore germination that are inhibited by various chemicals, and the mechanism of action of these inhibitors. The work also provides new insights into the process of spore germination itself.