Intellectual disability syndrome associated with a homozygous founder variant in SGSM3 in Ashkenazi Jews

BACKGROUND

Neurodevelopmental disorders (NDDs) impact both the development and functioning of the brain and exhibit clinical and genetic variability. RAP and RAB proteins, belonging to the RAS superfamily, are identified as established contributors to NDDs. However, the involvement of SGSM (small G protein signalling modulator), another member of the RAS family, in NDDs has not been previously documented.

METHODS

Proband-only or trio exome sequencing was performed on DNA samples obtained from affected individuals and available family members. The variant prioritisation process focused on identifying rare deleterious variants. International collaboration aided in the identification of additional affected individuals.

RESULTS

We identified 13 patients from 8 families of Ashkenazi Jewish origin who all carried the same homozygous frameshift variant in SGSM3 gene. The variant was predicted to cause a loss of function, potentially leading to impaired protein structure or function. The variant co-segregated with the disease in all available family members. The affected individuals displayed mild global developmental delay and mild to moderate intellectual disability. Additional prevalent phenotypes observed included hypotonia, behavioural challenges and short stature.

CONCLUSIONS

An Ashkenazi Jewish homozygous founder variant in SGSM3 was discovered in individuals with NDDs and short stature. This finding establishes a connection between another member of the RAS family and NDDs. Additional research is needed to uncover the specific molecular mechanisms by which SGSM3 influences neurodevelopmental processes and the regulation of growth.

Diagnostic Utility of Exome Sequencing Among Israeli Children With Kidney Failure

Introduction

Genetic etiologies are estimated to account for a large portion of chronic kidney diseases (CKD) in children. However, data are lacking regarding the true prevalence of monogenic etiologies stemming from an unselected population screen of children with advanced CKD.

Methods

We conducted a national multicenter prospective study of all Israeli pediatric dialysis units to provide comprehensive "real-world" evidence for the genetic basis of childhood kidney failure in Israel. We performed exome sequencing and assessed the genetic diagnostic yield.

Results

Between 2019 and 2022, we recruited approximately 88% (n = 79) of the children on dialysis from all 6 Israeli pediatric dialysis units. We identified genetic etiologies in 36 of 79 (45%) participants. The most common subgroup of diagnostic variants was in congenital anomalies of the kidney and urinary tract causing genes (e.g., EYA1, HNF1B, PAX2, COL4A1, and NFIA) which together explain 28% of all monogenic etiologies. This was followed by mutations in genes causing renal cystic ciliopathies (e.g., NPHP1, NPHP4, PKHD1, and BBS9), steroid-resistant nephrotic syndrome (e.g., LAGE3, NPHS1, NPHS2, LMX1B, and SMARCAL1) and tubulopathies (e.g., CTNS and AQP2). The genetic diagnostic yield was higher among Arabs compared to Jewish individuals (55% vs. 29%) and in children from consanguineous compared to nonconsanguineous families (63% vs. 29%). In 5 participants (14%) with genetic diagnoses, the molecular diagnosis did not correspond with the pre-exome diagnosis. Genetic diagnosis has a potential influence on clinical management in 27 of 36 participants (75%).

Conclusion

Exome sequencing in an unbiased Israeli nationwide dialysis-treated kidney failure pediatric cohort resulted in a genetic diagnostic yield of 45% and can often affect clinical decision making.

Adult-onset Alexander disease among patients of Jewish Syrian descent

Alexander disease (AxD) is a rare autosomal dominant leukodystrophy caused by heterozygous mutations in the glial fibrillary acid protein (GFAP) gene. The age of symptoms onset ranges from infancy to adulthood, with variable clinical and radiological manifestations. Adult-onset AxD manifests as a chronic and progressive condition, characterized by bulbar, motor, cerebellar, and other clinical signs and symptoms. Neuroradiological findings typically involve the brainstem and cervical spinal cord. Adult-onset AxD has been described in diverse populations but is rare in Israel. We present a series of patients diagnosed with adult-onset AxD from three families, all of Jewish Syrian descent. Five patients (4 females) were diagnosed with adult-onset AxD due to the heterozygous mutation c.219G > A, p.Met73Ile in GFAP. Age at symptoms onset ranged from 48 to 61 years. Clinical characteristics were typical and involved progressive bulbar and gait disturbance, followed by pyramidal and cerebellar impairment, dysautonomia, and cognitive decline. Imaging findings included medullary and cervical spinal atrophy and mostly infratentorial white matter hyperintensities. A newly recognized cluster of adult-onset AxD in Jews of Syrian origin is presented. This disorder should be considered in differential diagnosis in appropriate circumstances. Genetic counselling for family members is required in order to discuss options for future family planning.

Investigating two mobile just-in-time adaptive interventions to foster psychological resilience: research protocol of the DynaM-INT study

BACKGROUND

Stress-related disorders such as anxiety and depression are highly prevalent and cause a tremendous burden for affected individuals and society. In order to improve prevention strategies, knowledge regarding resilience mechanisms and ways to boost them is highly needed. In the Dynamic Modelling of Resilience - interventional multicenter study (DynaM-INT), we will conduct a large-scale feasibility and preliminary efficacy test for two mobile- and wearable-based just-in-time adaptive interventions (JITAIs), designed to target putative resilience mechanisms. Deep participant phenotyping at baseline serves to identify individual predictors for intervention success in terms of target engagement and stress resilience.

METHODS

DynaM-INT aims to recruit N = 250 healthy but vulnerable young adults in the transition phase between adolescence and adulthood (18-27 years) across five research sites (Berlin, Mainz, Nijmegen, Tel Aviv, and Warsaw). Participants are included if they report at least three negative burdensome past life events and show increased levels of internalizing symptoms while not being affected by any major mental disorder. Participants are characterized in a multimodal baseline phase, which includes neuropsychological tests, neuroimaging, bio-samples, sociodemographic and psychological questionnaires, a video-recorded interview, as well as ecological momentary assessments (EMA) and ecological physiological assessments (EPA). Subsequently, participants are randomly assigned to one of two ecological momentary interventions (EMIs), targeting either positive cognitive reappraisal or reward sensitivity. During the following intervention phase, participants' stress responses are tracked using EMA and EPA, and JITAIs are triggered if an individually calibrated stress threshold is crossed. In a three-month-long follow-up phase, parts of the baseline characterization phase are repeated. Throughout the entire study, stressor exposure and mental health are regularly monitored to calculate stressor reactivity as a proxy for outcome resilience. The online monitoring questionnaires and the repetition of the baseline questionnaires also serve to assess target engagement.

DISCUSSION

The DynaM-INT study intends to advance the field of resilience research by feasibility-testing two new mechanistically targeted JITAIs that aim at increasing individual stress resilience and identifying predictors for successful intervention response. Determining these predictors is an important step toward future randomized controlled trials to establish the efficacy of these interventions.

GATA2 Deficiency in Adult Life Is Characterized by Phenotypic Diversity and Delayed Diagnosis

The transcription factor GATA2 plays a key role in the survival and self-renewal of hematopoietic stem and progenitor cells. Autosomal dominant variants in GATA2 cause a broad spectrum of heterogeneous phenotypes. Here, we present our experience with GATA2 deficiency in a retrospective multicenter analysis of computerized medical records of adult patients (age ≥18 years) treated between 2018 and 2022 at Shaare Zedek Medical Center in Jerusalem and Sheba Tel-Hashomer Medical Center in Ramat Gan, Israel. Two male and two female patients with GATA2 deficiency were identified. Three of the patients presented with symptoms in adult life and all patients were diagnosed as adults. Age at presentation was 10.5-36 years and age at diagnosis 24-47 years. Diagnosis was delayed in all patients by 1-24.5 years. The phenotypic diversity was notable. Patients presented with myelodysplastic syndrome (n=2), pulmonary alveolar proteinosis (n=1), and recurrent viral (n=1), bacterial (n=3), and mycobacterial (n=1) infections. Bone marrow biopsy revealed cytogenetic abnormalities in one patient (monosomy 7). Patients were diagnosed by exome sequencing (n=3) and Sanger sequencing of the coding exons in GATA2 (n=1). Novel heterozygous GATA2 variants (c.177C>A, p.Y59* and c.610dup, p.R204Pfs*78) were identified in two patients. Immune workup revealed B cell lymphopenia and monocytopenia in all tested patients. One patient died from overwhelming sepsis despite all patients being treated with antibiotics and anti-mycobacterials. Our cohort highlights the phenotypic diversity, late presentation, and delayed diagnosis of GATA2 deficiency. Increased awareness of this primary immune deficiency presenting in adult life is needed and should involve a high index of suspicion.

FC035: Exome Sequencing of the Israeli Dialysis-Treated Pediatric Population Reveals Monogenic Etiology in ∼44% of Cases

BACKGROUND

Chronic kidney disease in children is estimated to be secondary to a monogenic etiology in ∼20% of patients and can arise from mutations in a multitude of different single-gene causes. Still, data are lacking on the true prevalence of genetic etiologies dates from a large scale unbiased population screen of children with advanced kidney disease.

METHOD

In order to provide comprehensive real-world evidence for monogenic etiologies of childhood end-stage kidney disease—on a national level—we initiated a nation-wide multicenter study of all pediatric Israeli dialysis units. Specifically, between 2020 and 2021, we recruited ∼90% (n = 66) of children on dialysis from all six dialysis units treating children in Israel. We conducted exome sequencing and diagnostic analysis for all patients. We assessed the diagnostic yield of genetic analysis and its relation to baseline clinical phenotypes.

RESULTS

Overall, the cohort comprises 66 individuals from different families with a first-degree consanguinity rate of 47%. Participants' mean age at renal replacement therapy initiation was 8.1 years (range 1-month to 20-years). Using exome sequencing we identified a genetic etiology in 29 out of 66 (44%) participants. The most common subgroup of diagnostic variants was in genes causing renal cystic ciliopathies (e.g. NPHP1, NPHP4, PKHD1 and BBS9), which together explain 31% of all monogenic etiologies. This was followed by mutations in genes causing CAKUT (e.g. EYA1, HNF1B, PAX2, COL4A1 and GREB1L), steroid-resistant nephrotic syndrome (e.g. LAGE3, NPHS1, NPHS2, LMX1B, SMARCAL1 and CRB2) and tubulopathies (e.g. CTNS, AQP2), which explain 21%, 21% and 17% of all genetic etiologies, respectively. The yield of exome sequencing was higher among non-Jewish compared with Jewish individuals (52% versus 29%) and in children from consanguineous families compared with non-consanguineous families (56% versus 31%). The final molecular diagnosis did not correspond with the pre-exome clinical diagnosis in 17% of cases.

CONCLUSION

Exome sequencing in an unbiased pediatric cohort with end-stage kidney disease yields a genetic diagnosis in 44% of cases and reveals many underappreciated monogenic etiologies. Surprisingly, renal cystic ciliopathies causing-genes were more common than CAKUT genes in our cohort. These results emphasize the importance of genetic testing among children with advanced chronic kidney disease and validate the role of exome sequencing as a standard routine diagnostic tool.

SUMOylation of linker histone H1 drives chromatin condensation and restriction of embryonic cell fate identity

The fidelity of the early embryonic program is underlined by tight regulation of the chromatin. Yet, how the chromatin is organized to prohibit the reversal of the developmental program remains unclear. Specifically, the totipotency-to-pluripotency transition marks one of the most dramatic events to the chromatin, and yet, the nature of histone alterations underlying this process is incompletely characterized. Here, we show that linker histone H1 is post-translationally modulated by SUMO2/3, which facilitates its fixation onto ultra-condensed heterochromatin in embryonic stem cells (ESCs). Upon SUMOylation depletion, the chromatin becomes de-compacted and H1 is evicted, leading to totipotency reactivation. Furthermore, we show that H1 and SUMO2/3 jointly mediate the repression of totipotent elements. Lastly, we demonstrate that preventing SUMOylation on H1 abrogates its ability to repress the totipotency program in ESCs. Collectively, our findings unravel a critical role for SUMOylation of H1 in facilitating chromatin repression and desolation of the totipotent identity.

A single center experience with publicly funded clinical exome sequencing for neurodevelopmental disorders or multiple congenital anomalies

Exome sequencing (ES) is an important diagnostic tool for individuals with neurodevelopmental disorders (NDD) and/or multiple congenital anomalies (MCA). However, the cost of ES limits the test's accessibility for many patients. We evaluated the yield of publicly funded clinical ES, performed at a tertiary center in Israel, over a 3-year period (2018–2020). Probands presented with (1) moderate-to-profound global developmental delay (GDD)/intellectual disability (ID); or (2) mild GDD/ID with epilepsy or congenital anomaly; and/or (3) MCA. Subjects with normal chromosomal microarray analysis who met inclusion criteria were included, totaling 280 consecutive cases. Trio ES (proband and parents) was the default option. In 252 cases (90.0%), indication of NDD was noted. Most probands were males (62.9%), and their mean age at ES submission was 9.3 years (range 1 month to 51 years). Molecular diagnosis was reached in 109 probands (38.9%), mainly due to de novo variants (91/109, 83.5%). Disease-causing variants were identified in 92 genes, 15 of which were implicated in more than a single case. Male sex, families with multiple-affected members and premature birth were significantly associated with lower ES yield (p < 0.05). Other factors, including MCA and coexistence of epilepsy, autism spectrum disorder, microcephaly or abnormal brain magnetic resonance imaging findings, were not associated with the yield. To conclude, our findings support the utility of clinical ES in a real-world setting, as part of a publicly funded genetic workup for individuals with GDD/ID and/or MCA.

Principles of signaling pathway modulation for enhancing human naive pluripotency induction

Isolating human MEK/ERK signaling-independent pluripotent stem cells (PSCs) with naive pluripotency characteristics while maintaining differentiation competence and (epi)genetic integrity remains challenging. Here, we engineer reporter systems that allow the screening for defined conditions that induce molecular and functional features of human naive pluripotency. Synergistic inhibition of WNT/β-CATENIN, protein kinase C (PKC), and SRC signaling consolidates the induction of teratoma-competent naive human PSCs, with the capacity to differentiate into trophoblast stem cells (TSCs) and extraembryonic naive endodermal (nEND) cells in vitro. Divergent signaling and transcriptional requirements for boosting naive pluripotency were found between mouse and human. P53 depletion in naive hPSCs increased their contribution to mouse-human cross-species chimeric embryos upon priming and differentiation. Finally, MEK/ERK inhibition can be substituted with the inhibition of NOTCH/RBPj, which induces alternative naive-like hPSCs with a diminished risk for deleterious global DNA hypomethylation. Our findings set a framework for defining the signaling foundations of human naive pluripotency.

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Inhibition of SRC, PKC, and WNT consolidates human naive pluripotency induction

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Competitiveness of p53 depleted human PSCs in cross-species chimeric embryos

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Opposing net effect for ACTIVIN and WNT on mouse versus human naive pluripotency

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2i and ERKi independent alternative human naive-like PSC conditions

Context-dependent functional compensation between Ythdf m6A reader proteins

The N6-methyladenosine (m6A) modification is the most prevalent post-transcriptional mRNA modification, regulating mRNA decay and splicing. It plays a major role during normal development, differentiation, and disease progression. The modification is regulated by a set of writer, eraser, and reader proteins. The YTH domain family of proteins consists of three homologous m6A-binding proteins, Ythdf1, Ythdf2, and Ythdf3, which were suggested to have different cellular functions. However, their sequence similarity and their tendency to bind the same targets suggest that they may have overlapping roles. We systematically knocked out (KO) the Mettl3 writer, each of the Ythdf readers, and the three readers together (triple-KO). We then estimated the effect in vivo in mouse gametogenesis, postnatal viability, and in vitro in mouse embryonic stem cells (mESCs). In gametogenesis, Mettl3-KO severity is increased as the deletion occurs earlier in the process, and Ythdf2 has a dominant role that cannot be compensated by Ythdf1 or Ythdf3, due to differences in readers' expression pattern across different cell types, both in quantity and in spatial location. Knocking out the three readers together and systematically testing viable offspring genotypes revealed a redundancy in the readers' role during early development that is Ythdf1/2/3 gene dosage-dependent. Finally, in mESCs there is compensation between the three Ythdf reader proteins, since the resistance to differentiate and the significant effect on mRNA decay occur only in the triple-KO cells and not in the single KOs. Thus, we suggest a new model for the Ythdf readers function, in which there is profound dosage-dependent redundancy when all three readers are equivalently coexpressed in the same cell types.

Human non-olfactory cognition phase-locked with inhalation

Olfactory stimulus acquisition is perfectly synchronized with inhalation, which tunes neuronal ensembles for incoming information. Because olfaction is an ancient sensory system that provided a template for brain evolution, we hypothesized that this link persisted, and therefore nasal inhalations may also tune the brain for acquisition of non-olfactory information. To test this, we measured nasal airflow and electroencephalography during various non-olfactory cognitive tasks. We observed that participants spontaneously inhale at non-olfactory cognitive task onset and that such inhalations shift brain functional network architecture. Concentrating on visuospatial perception, we observed that nasal inhalation drove increased task-related brain activity in specific task-related brain regions and resulted in improved performance accuracy in the visuospatial task. Thus, mental processes with no link to olfaction are nevertheless phase-locked with nasal inhalation, consistent with the notion of an olfaction-based template in the evolution of human brain function.

Neutralizing Gatad2a-Chd4-Mbd3/NuRD Complex Facilitates Deterministic Induction of Naive Pluripotency

Mbd3, a member of nucleosome remodeling and deacetylase (NuRD) co-repressor complex, was previously identified as an inhibitor for deterministic induced pluripotent stem cell (iPSC) reprogramming, where up to 100% of donor cells successfully complete the process. NuRD can assume multiple mutually exclusive conformations, and it remains unclear whether this deterministic phenotype can be attributed to a specific Mbd3/NuRD subcomplex. Moreover, since complete ablation of Mbd3 blocks somatic cell proliferation, we aimed to explore functionally relevant alternative ways to neutralize Mbd3-dependent NuRD activity. We identify Gatad2a, a NuRD-specific subunit, whose complete deletion specifically disrupts Mbd3/NuRD repressive activity on the pluripotency circuitry during iPSC differentiation and reprogramming without ablating somatic cell proliferation. Inhibition of Gatad2a facilitates deterministic murine iPSC reprogramming within 8 days. We validate a distinct molecular axis, Gatad2a-Chd4-Mbd3, within Mbd3/NuRD as being critical for blocking reestablishment of naive pluripotency and further highlight signaling-dependent and post-translational modifications of Mbd3/NuRD that influence its interactions and assembly.

A multiplexed screening method for pluripotency

Measurement of Alkaline Phosphatase (ALP) level is a widely used procedure in clinical and basic research. We present a simple and inexpensive luminescence-based method that allows multiplexed measurement and normalization of intracellular ALP levels in one sample well. The method comprises two commercially available reagents enabling quantification of ALP levels and cell number by two sequential luminescence readouts. Using this method we were able to detect and analyze somatic reprogramming into pluripotent stem cells. The method is highly applicable for High Throughput Screening (HTS) campaigns and analysis.

Characteristics of Synthetic Cannabinoid and Cannabis Users Admitted to a Psychiatric Hospital: A Comparative Study

BACKGROUND

Psychotic and affective exacerbations associated with synthetic cannabinoid (SC) use are becoming an emerging concern in psychiatric hospitals. However, data are lacking regarding whether clinical manifestations of SC use differ from those associated with cannabis use.

OBJECTIVE

Our aim was to explore the unique profile of SC users admitted to a mental health center in terms of demographic, clinical, and physiologic variables in comparison to cannabis users.

METHODS

We retrieved retrospective data of patients admitted to a mental health center between October 2007 and May 2014 who self-reported recent use of SC (n = 60) and patients who were cannabis users (positive carboxy-tetrahydrocannabinol urine test at admission) without a history of SC use (n = 163). Clinical measures included hospitalization length, number of previous hospitalizations, Positive and Negative Syndrome Scale (PANSS) scores, psychiatric status at admission, and relevant physiologic and laboratory parameters.

RESULTS

Hospitalized SC users were younger than hospitalized cannabis users (n = 163) (30.46 ± 7.83 years versus 34.67 ± 10.07 years, U₂₂₃ = 3,781.5, P = .009, respectively). SC patients had longer hospitalizations compared to cannabis users (43.45 ± 54.02 days versus 22.91 ± 31.36 days, U₂₁₉ = 5,701.5, P = .005, respectively), had more previous hospitalizations (3.73 ± 5.05 versus 1.98 ± 5.12, U₂₂₃ = 6,284, P < .001, respectively), and were more likely to be hospitalized by criminal court order (36.7% [n = 22] versus 19.9% [n = 32], χ²₂ = 7.136, P = .028, respectively). SC patients presented with a more severe clinical picture manifested by higher total PANSS scores (82.53 ± 23.05 versus 69.98 ± 19.94, t₉₁ = -2.696, P = .008) in a subset of patients with PANSS scores assessed within a week from admission (n = 30 in the SC group and n = 63 in the cannabis group). No differences were found in physiologic or laboratory measures on admission between the SC and cannabis groups.

CONCLUSIONS

Patients admitted following use of SC are generally younger males who have higher severity of psychotic symptoms at admission, are more likely to be admitted by criminal court order, and require longer hospitalization periods in comparison to cannabis users.

Myelin-associated glycoprotein gene mutation causes Pelizaeus-Merzbacher disease-like disorder

Pelizaeus-Merzbacher disease is an X-linked hypomyelinating leukodystrophy caused by mutations or rearrangements in PLP1. It presents in infancy with nystagmus, jerky head movements, hypotonia and developmental delay evolving into spastic tetraplegia with optic atrophy and variable movement disorders. A clinically similar phenotype caused by recessive mutations in GJC2 is known as Pelizaeus-Merzbacher-like disease. Both genes encode proteins associated with myelin. We describe three siblings of a consanguineous family manifesting the typical infantile-onset Pelizaeus-Merzbacher disease-like phenotype slowly evolving into a form of complicated hereditary spastic paraplegia with mental retardation, dysarthria, optic atrophy and peripheral neuropathy in adulthood. Magnetic resonance imaging and spectroscopy were consistent with a demyelinating leukodystrophy. Using genetic linkage and exome sequencing, we identified a homozygous missense c.399C>G; p.S133R mutation in MAG. This gene, previously associated with hereditary spastic paraplegia, encodes myelin-associated glycoprotein, which is involved in myelin maintenance and glia-axon interaction. This mutation is predicted to destabilize the protein and affect its tertiary structure. Examination of the sural nerve biopsy sample obtained in childhood in the oldest sibling revealed complete absence of myelin-associated glycoprotein accompanied by ill-formed onion-bulb structures and a relatively thin myelin sheath of the affected axons. Immunofluorescence, cell surface labelling, biochemical analysis and mass spectrometry-based proteomics studies in a variety of cell types demonstrated a devastating effect of the mutation on post-translational processing, steady state expression and subcellular localization of myelin-associated glycoprotein. In contrast to the wild-type protein, the p.S133R mutant was retained in the endoplasmic reticulum and was subjected to endoplasmic reticulum-associated protein degradation by the proteasome. Our findings identify involvement of myelin-associated glycoprotein in this family with a disorder affecting the central and peripheral nervous system, and suggest that loss of the protein function is responsible for the unique clinical phenotype.

Stem cells. m6A mRNA methylation facilitates resolution of naïve pluripotency toward differentiation

Naïve and primed pluripotent states retain distinct molecular properties, yet limited knowledge exists on how their state transitions are regulated. Here, we identify Mettl3, an N(6)-methyladenosine (m(6)A) transferase, as a regulator for terminating murine naïve pluripotency. Mettl3 knockout preimplantation epiblasts and naïve embryonic stem cells are depleted for m(6)A in mRNAs, yet are viable. However, they fail to adequately terminate their naïve state and, subsequently, undergo aberrant and restricted lineage priming at the postimplantation stage, which leads to early embryonic lethality. m(6)A predominantly and directly reduces mRNA stability, including that of key naïve pluripotency-promoting transcripts. This study highlights a critical role for an mRNA epigenetic modification in vivo and identifies regulatory modules that functionally influence naïve and primed pluripotency in an opposing manner.

Deterministic direct reprogramming of somatic cells to pluripotency

Somatic cells can be inefficiently and stochastically reprogrammed into induced pluripotent stem (iPS) cells by exogenous expression of Oct4 (also called Pou5f1), Sox2, Klf4 and Myc (hereafter referred to as OSKM). The nature of the predominant rate-limiting barrier(s) preventing the majority of cells to successfully and synchronously reprogram remains to be defined. Here we show that depleting Mbd3, a core member of the Mbd3/NuRD (nucleosome remodelling and deacetylation) repressor complex, together with OSKM transduction and reprogramming in naive pluripotency promoting conditions, result in deterministic and synchronized iPS cell reprogramming (near 100% efficiency within seven days from mouse and human cells). Our findings uncover a dichotomous molecular function for the reprogramming factors, serving to reactivate endogenous pluripotency networks while simultaneously directly recruiting the Mbd3/NuRD repressor complex that potently restrains the reactivation of OSKM downstream target genes. Subsequently, the latter interactions, which are largely depleted during early pre-implantation development in vivo, lead to a stochastic and protracted reprogramming trajectory towards pluripotency in vitro. The deterministic reprogramming approach devised here offers a novel platform for the dissection of molecular dynamics leading to establishing pluripotency at unprecedented flexibility and resolution.

Early bactericidal activity of isoniazid in pulmonary tuberculosis. Optimization of methodology. The DATRI 008 Study Group

Early bactericidal activity (EBA) of antituberculosis drugs is the rate of decrease in the concentration of tubercle bacilli sputum during the initial days of therapy. The study reported here was designed to optimize the methodology for obtaining precise EBA measurements. The study compared the results with two versus five treatment days; overnight sputum collections with early morning collections; and quantitative smears for acid-fast bacilli (AFB) with quantitative cultures. Isoniazid (INH) was used as a model drug. Among 28 smear-positive patients enrolled in the study in five cities in the United States, 16 were evaluable (INH-susceptible tuberculosis [TB] and adequate sputum collections). The mean baseline bacterial load was 6.69 log10 cfu/ml (SE = 0.24). Quantitative culture of 10- or 12-h sputum collections obtained on two baseline days and treatment Day 5 was the optimal method for EBA measurement. The mean 5-d EBA was 0.21 log10 cfu/ml/d (SE = 0.03; p < 0.001) and the EBA appeared to be constant during the first five treatment days. On the basis of these data, multiarm studies of investigational drugs will require 25 evaluable subjects per arm to detect (80% power and two-tailed alpha of 0.05) an EBA at least 50% as large as the EBA of INH. In countries with a low incidence of TB, the usefulness of this methodology for rapidly assessing new antituberculosis agents may be limited by the relatively large number of subjects required to compare EBA values across treatment arms.

Synergistic activities of clarithromycin and pyrazinamide against Mycobacterium tuberculosis in human macrophages

The combination of clarithromycin and pyrazinamide was found to be synergistic against Mycobacterium tuberculosis in human macrophages. MICs were four- to eightfold lower for this combination than they were for either drug alone. Clarithromycin and rifampin, however, had only an additive effect.

Viscosity and refractive index of follicular fluid in relation to in vitro fertilization

PURPOSE

To set the standard values of follicular fluid viscosity and refractive index, and to investigate a possible relationship between these physiological parameters and the outcome of in vitro fertilization treatment.

DESIGN AND RESULTS

128 samples of follicular fluid were collected from 40 in vitro fertilization patients. Viscosity determinations (centipoise; mean +/- SD) for shear rates of 23, 46, 115, and 230 were 2.04 +/- 0.86, 1.84 +/- 0.49, 1.48 +/- 0.27, and 1.38 +/- 0.22, respectively. The average (+/- SD) refractive index was 1.030 +/- 0.002. There was no significant difference between the values of thawed frozen fluids and fresh samples of the same specimens. The data showed no correlation between follicular fluid viscosity or refractive index and the presence of oocytes, their maturation grade or their fertilizing capacity.

CONCLUSIONS

For the first time, values of the viscosity and refractive index of follicular fluid obtained during in vitro fertilization have been determined. However, these preliminary results did not reveal any relationship between the physiological parameters examined and the outcome of in vitro fertilization treatment.

Bacteriostatic and bactericidal activities of benzoxazinorifamycin KRM-1648 against Mycobacterium tuberculosis and Mycobacterium avium in human macrophages

Inhibitory and bactericidal activities of KRM-1648 were determined against Mycobacterium tuberculosis and M. avium residing in human monocyte-derived macrophages and extracellular M. tuberculosis and M. avium. MICs and MBCs of KRM-1648 against intracellular and extracellular bacteria were substantially lower than those of rifampin. The MICs and MBCs of either drug against the intracellular bacteria were only twofold lower than or equal to the values found for extracellular bacteria. The prolonged effect of KRM-1648 found in this study is probably associated with high ratios of intracellular accumulation, which were 50- to 100-fold higher than that found for rifampin. Further studies on intracellular distribution of KRM-1648 and on the sites of actual interaction between the drug and bacteria residing in macrophages are necessary, as well as evaluation of combined effects of KRM-1648 with other drugs in long-term macrophage culture experiments.

Comparison of activities of rifapentine and rifampin against Mycobacterium tuberculosis residing in human macrophages

The activities of rifapentine and rifampin against Mycobacterium tuberculosis residing in human monocyte-derived macrophages were determined. The MICs and MBCs of rifapentine for intracellular bacteria were two- to fourfold lower than those of rifampin. For extracellular bacteria, this difference was less noticeable. Nevertheless, the more favorable pharmacokinetics of rifapentine over rifampin was addressed in other experimental models. These models showed substantial differences after short pulsed exposures of the infected macrophages to the drugs and when the infected macrophages were exposed to changing drug concentrations that imitated the pharmacokinetic curves observed in blood. Once-a-week exposures to rifapentine concentrations equivalent to those attained in blood after one 600-mg dose resulted during the first week in a dramatic decline in the number of bacteria, and this decline was maintained at a minimal level for a period of four weeks. The results of this study have shown the suitability of rifapentine for intermittent-treatment regimens. The prolonged effect of rifapentine found in this study may be associated with high ratios of intracellular accumulation, which were four- to fivefold higher than those found for rifampin. Further studies on the intracellular distribution of rifamycins and on the sites of actual interaction between the drugs and bacteria residing in macrophages are necessary.

Splinting therapy for congenital auricular deformities with the use of soft material

Congenital auricular deformities present serious esthetic problems. To avoid surgical correction, splinting during the early neonatal period has been attempted. We describe the results and follow-up of splinting therapy with a special soft material in 30 neonates, as compared with results in a control group of 20 untreated newborn infants. Good results were achieved in 85% of the patients and sufficient results in 15% when the treatment was continuous over the entire 4-week period. However, when treatment was partial or discontinuous, only 10% had good results. None of the infants in the control group showed spontaneous improvement during the period of study. Moreover, early initiation of treatment (first week of life) proved more effective than later treatment (second week of life). Strong parental cooperation and close follow-up are also important for success.

Methods for determining concentrations of antimicrobial agents in human monocytes

Human monocytes can be derived from the leukocyte-rich by-product of donors' blood available after platelet separation. Large volumes of the monocyte samples obtained from this product provided an opportunity to conduct experiments with relatively high concentrations of the antimicrobial agents sufficient for their detection in bioassays, thus avoiding the necessity of working with the radiolabelled drugs. Washing of the cells after their exposure to the drug may lead to an extraction of the tested agent from the cell, especially if it is a substance of low molecular weight. In our experiments we excluded the washing step, and separated the monocytes from the extracellular medium by velocity gradient centrifugation. In experiments with two rifamycins, the cell pellet as well as the extracellular fluid were subjected to a bioassay using Micrococcus luteus as a target organism. The method showed good reproducibility and consistency in results obtained.

Effects of clarithromycin and rifabutin alone and in combination on intracellular and extracellular replication of Mycobacterium avium

The combined effect of clarithromycin and rifabutin against Mycobacterium avium multiplying either within human monocyte-derived macrophages or extracellularly in a liquid medium was additive: both MICs and MBCs were twofold lower for the combination than they were for each drug alone. Prolonged exposure for 4 weeks of M. avium-infected macrophages to combined concentrations that were only twofold greater than the MICs resulted in a 100-fold decrease in the number of viable bacteria, while in the drug-free controls a 100-fold or greater increase in comparison with the initial viable counts took place. Comparison of this effect with the results of the prolonged exposure to each drug alone suggested that under these experimental conditions rifabutin enhanced the antimicrobial activity of clarithromycin against intracellular bacteria. At the same time, inhibition of intracellular growth by a 2-h pulsed exposure of the infected macrophages to the combination of the two drugs was not different from the effect induced by clarithromycin alone. In conclusion, clarithromycin played the major role in the antimicrobial activity of the tested combination, while rifabutin may have enhanced this effect during a prolonged exposure of the intracellular bacteria to these two agents.

Inhibitory and bactericidal activities of levofloxacin against Mycobacterium tuberculosis in vitro and in human macrophages

Levofloxacin exhibited twofold greater inhibitory and bactericidal activities than ofloxacin against either extracellular or intracellular tubercle bacilli. The activities of both drugs against extracellular and intracellular bacteria were about the same, despite the accumulation of the drugs in macrophages at a level four- to fivefold greater than that in the extracellular medium. The activities of both drugs against intracellular bacteria were largely associated with the short, 2-h pulsed exposures of the infected macrophages to the concentrations which correspond to those attainable in blood during the period of the maximum concentration of drug in serum.

Accumulation of clarithromycin in macrophages infected with Mycobacterium avium

Clarithromycin is known to accumulate in polymorphonuclear leukocytes, but no accumulation studies with macrophages have been reported. We exposed J774 macrophages, grown for 4-6 days, to clarithromycin 3.0 micrograms/ml for 2 hours. The cells were separated from the extracellular fluid, and the concentration of clarithromycin was determined in an agar diffusion bioassay. The accumulation of clarithromycin was 15.8-fold greater in the cells than it was in the extracellular fluid when the test was performed with noninfected cells, and 17.3-fold greater for cells infected with Mycobacterium avium. However, the ratio was substantially lower, only 3.7 for dead macrophages, suggesting that intracellular accumulation is probably an active process. These data may clarify the nature of the activity of clarithromycin against M. avium in macrophages.

Mycobacterium avium strains resistant to clarithromycin and azithromycin

Mycobacterium avium strains susceptible to clarithromycin and azithromycin contain mutants resistant to these macrolides with a frequency of 1.1 x 10(-10) to 1.2 x 10(-6). Cross-resistance between clarithromycin and azithromycin was demonstrated with mutants selected in the laboratory as well as with resistant strains isolated from patients. The susceptibility-resistance patterns of the macrolide-resistant strains with drugs other than macrolides were the same as those of the original susceptible strains. The emergence of clarithromycin resistance in patients was a result of multiplication of the preexisting resistant mutants that survived the elimination of bacteria during the initial period of treatment and was an exclusive cause of the relapse of bacteremia.

Inhibition of intracellular growth of Mycobacterium avium by one pulsed exposure of infected macrophages to clarithromycin

A single 2-h pulsed exposure of either human monocyte-derived macrophages or J774 cells infected with Mycobacterium avium to clarithromycin at 3.0 micrograms/ml completely inhibited the intracellular bacterial growth during the first four days of observation, and then only a slight increase in the number of CFU per milliliter took place between the fourth and seventh days. These data suggest that in vivo the intracellular bacteria can be effectively inhibited after a short period when the concentration of the drug in blood reaches its maximum. On the basis of these data, the assumptions that the elimination of bacteremia observed in clarithromycin clinical trials is a result of the activity of the drug not only against bacteria in blood but in macrophages as well and that the peak concentration attainable in blood is essential for these effects can be made.

Transient hepatic dysfunction in an infant of an epileptic mother treated with carbamazepine during pregnancy and breastfeeding

OBJECTIVE

A case is reported of a carbamazepine (CBZ)-treated epileptic mother whose newborn presented with transient hepatic dysfunction characterized by direct hyperbilirubinemia and high concentrations of gamma-glutamyltransferase (GGT).

DATA SOURCES

Information was obtained from case reports, clinical trials, and relevant bibliographic laboratory studies.

DATA EXTRACTION

Data from case reports were evaluated and compared with those from our patient. The hepatotoxic reactions together with the microsomal enzymatic induction of CBZ were reviewed.

DATA SYNTHESIS

A female infant born to an epileptic mother treated with CBZ throughout pregnancy and breastfeeding presented with transient direct hyperbilirubinemia and high concentrations of GGT. The characteristics of her transient hepatic dysfunction were: early appearance (during the first day of life); discrepancy between the normal liver enzymes and high GGT concentrations; slow decrease of GGT, which nevertheless remained at above-normal concentrations even after the complete disappearance of direct hyperbilirubinemia; and spontaneous resolution in spite of only occasional breastfeeding. The possible explanations of this transient hepatic dysfunction (like enzymatic induction) are discussed.

CONCLUSIONS

CBZ-induced hepatic dysfunction in neonates appears to have different clinical expressions. Infants of epileptic mothers treated with CBZ throughout pregnancy and breastfeeding should be carefully monitored for possible adverse effects.

MICs and MBCs of clarithromycin against Mycobacterium avium within human macrophages

The inhibitory and bactericidal activities of clarithromycin were determined quantitatively against the intracellular populations of five Mycobacterium avium strains growing in monocyte-derived human macrophages. The MICs were 1.0 microgram/ml, and the MBCs ranged from 16.0 to 64.0 micrograms/ml; these values were similar to the MICs and MBCs found in broth cultures at pH 7.4 and were substantially lower than those found in broth cultures at pHs 6.8 and 5.0. Since the intracellular environment has a neutral or even an acidic pH, relatively low MICs and MBCs found in macrophage cultures can be associated with the fact that the drug concentrations in macrophages are substantially higher than those in the medium in which these cells are cultivated. Pretreatment of the macrophages 2 days prior to infection decreased the MICs twofold in comparison with results of experiments in which the drug was added to already infected macrophages.

Concurrent mammary gland hyperplasia and adrenocortical carcinoma in a domestic ferret

Mammary gland hyperplasia associated with adrenocortical carcinoma in a domestic ferret had a histologic appearance similar to that observed in cats. It is important to consider this hyperplastic condition in the differential diagnosis of mammary gland enlargement in the ferret.

Prevalence of minor congenital anomalies in newborns of diabetic mothers

Minor congenital anomalies (MCA) were assessed in the offspring of 802 gestational diabetic mothers, 117 pre-gestational diabetic mothers, and 380 offspring born to normal mothers. The prevalence of infants with MCA ranged between 19.4% and 20.5% in the three groups without any significant difference between them. There was no correlation between the prevalence and type of MCA and the severity of the diabetic state. Neither was there any correlation between the prevalence or type of MCA and the appearance or type of major congenital anomalies.

The disease of CBA and BALB/c mice that follows inoculation of a small number of Mycobacterium lepraemurium into the hind foot pad

To learn if the lack of an immune response in mice infected with Mycobacterium lepraemurium (MLM) was a consequence of the organisms, we studied the disease that followed inoculation of less than or equal to 5000 organisms into the hind foot pads of CBA and BALB/c mice. The mice of both strains demonstrated a rapid increase of bacterial numbers soon after inoculation, with a slowing of the rate of multiplication once the number of organisms per foot pad passed 3 x 10(7). By 1 year after inoculation, the numbers of organisms had reached levels greater than or equal to 10(11) in the spleen and liver, and greater than or equal to 10(8) in the femoral bone marrow. In mice that had been inoculated with as few as 5 MLM or 50 MLM, the organisms had multiplied to numbers greater than 10(8) in the foot pads and to greater than or equal to 10(9) in the spleens, suggesting that the ID50 of viable MLM may be less than or equal to 5 organisms per foot pad. No protection against superinfection could be demonstrated. On the other hand, initial multiplication of MLM in the foot pads was followed virtually immediately by the death of at least 97% of the organisms.

Blood-stained maternal milk: prevalence, characteristics and counselling

Blood-stained maternal milk at delivery and during lactation was prospectively studied in 7774 livebirths over a period of 2 years (1986-1988). Eight mothers had this atypical breast discharge, a prevalence rate of 1:971 livebirths (0.1%). The characteristics of this phenomenon were: early appearance (frequently a short time after delivery), with normal bacteriologic and cytologic investigations, disappearance in 2 to 5 days, without adverse effects on the mothers and their babies, no recurrence after cessation, and occurrence in the previous pregnancies (3 of the 5 multipara). As a result, the best policy is to reassure the parents about the benign and transient course of this condition and to recommend continuation of breast feeding.

Possible association between acetazolamide administration during pregnancy and metabolic disorders in the newborn

Development of metabolic acidosis, hypocalcemia and hypomagnesemia in a preterm infant whose mother was treated with acetazolamide throughout pregnancy is described. These neonatal metabolic alterations possibly related to acetazolamide administration in pregnancy have not been previously described in the literature. The metabolic acidosis was transient and resolved spontaneously despite breast feeding and continued administration of acetazolamide to the mother. Hypocalcemia and hypomagnesemia resolved quickly with appropriate treatment with calcium gluconate and magnesium sulphate, respectively. At follow-up at ages 1, 3 and 8 months, the baby showed mild hypertonicity of the lower limbs requiring physiotherapy.

Necrotizing enterocolitis after intravenous immunoglobulin treatment for neonatal isoimmune thrombocytopenia

A male neonate of 38 weeks' gestation with isoimmune neonatal thrombocytopenia treated with high dose intravenous immunoglobulin (IVIG) developed necrotizing enterocolitis (NEC) at 3 days of age. The known maternal and neonatal risk factors for the development of this disease were excluded. The association between high dose IVIG and the appearance of thrombotic events might be another aetiological factor for occurrence of NEC in a newborn infant.

Influence of phagosomal contents on the apparent inhibition of phagosome-lysosome fusion mediated by polyanionic substances in mouse peritoneal macrophages

The study of fusion of phagosomes with secondary lysosomes in macrophages is facilitated by assessing transfer of fluorescent or electron-opaque markers (or both) from the lysosomes to the phagosomes. When certain virulent viable pathogens are phagocytosed by mouse peritoneal macrophages, phagosome-lysosome fusion (P-LF) is inhibited. Nonviable counterparts ordinarily cannot impose this block. A similar, but spurious, block to P-LF seems to be mediated from the lysosomal domain following sequestration of certain polyanionic substances. This block has been judged to be relieved by, for example, heat-killed yeasts and various viable bacteria designated as fusion-inducing microorganisms, acting from the phagosome. In this study we tested this concept and believed it to be unfounded. Macrophages labeled with Thorotrast and incubated with dextran sulfate were offered a variety of viable and heat-killed microorganisms for phagocytosis: Saccharomyces cerevisiae, Mycobacterium lepraemurium, Streptococcus faecalis, and Escherichia coli. By electron microscopy, a transfer of Thorotrast to phagosomes up to 18 h was seen to be highly suppressed as compared with controls, but was not notably different for any of the targets, whether viable or not. Instead, inert 0.45-micron carboxylated polystyrene beads (the smallest target) showed the most delivery of marker. If polyanionic agents truly inhibited fusion, then "fusiogenic" microorganisms should free the marker for delivery. If polyanions do not inhibit P-LF and only trap the marker, the behavior of the various targets would correspond to what we found.

Enhancement of growth of Mycobacterium lepraemurium in macrophages by gamma interferon

Gamma interferon, an immune lymphokine that protects mouse macrophages against infection by several parasites, was ineffective against Mycobacterium lepraemurium. On the contrary, it significantly stimulated multiplication of M. lepraemurium in the macrophages. Simultaneous treatment of macrophages with gamma interferon and interleukin-4 or interleukin-2 or a combination of all three did not enhance the macrophage resistance to infection with M. lepraemurium, but instead stimulated growth of M. lepraemurium.

Haemophagocytosis and other haematological aspects of Mycobacterium lepraemurium disease of mice

CBA mice inoculated i.v. with 2 x 10(8) viable MLM were observed at intervals for 5 months. In the bone marrow, haematopoietic cells were progressively displaced by MLM-laden phagocytes; depletion of erythroid cells began earlier and was more pronounced than that of myeloid cells. Transiently, mild anaemia and profound leucopenia were noted. The spleen was enlarged and the site of increasing histiocytosis and extramedullary haematopoiesis which was accompanied by displacement of splenic parenchyma. The liver was enlarged and its parenchyma contained scattered islands of haematopoietic elements. Lymph node cells had been largely replaced by MLM-laden macrophages by the end of the process. Thus, MLM infection exerts important effects on haematopoiesis of susceptible mice and is accompanied by active extramedullary haematopoiesis. In addition, the haemophagocytosis, observed most commonly in immuno-compromised patients infected with certain viral or mycobacterial pathogens, was observed late in the course of MLM disease of mice.

Mycobacterium lepraemurium activates macrophages but fails to trigger release of superoxide anion

Mycobacterium lepraemurium failed to stimulate a normal respiratory burst when presented to mouse peritoneal or bone marrow macrophages. By comparison, Mycobacterium bovis (strain Bacillus Calmette-Guerin) or Saccharomyces cerevisiae, as expected, stimulated macrophages to release a large amount of superoxide anion (O2-). M. lepraemurium did not interfere with the response to yeast when both microbes were added together to macrophages. The low release of O2- induced by M. lepraemurium was not due to failure of M. lepraemurium to activate or prime macrophages, because exposure of macrophages to M. lepraemurium caused the expected enhancement of O2- release when the macrophages were stimulated by PMA. Similarly, macrophages taken from mice infected with M. lepraemurium were activated, as indicated by high PMA-stimulated O2- release. Macrophages primed in vitro by exposure to Escherichia coli LPS for 24 h did show a moderate O2- response when stimulated by M. lepraemurium, but macrophages primed by exposure to IFN-gamma muramyl dipeptide, or M. lepraemurium showed a weak response when subsequently challenged with M. lepraemurium. The priming effect of M. lepraemurium or LPS decreased substantially after macrophages were cultured in fresh medium for 24 h. Heat killing or opsonization of M. lepraemurium caused the M. lepraemurium to stimulate a high amount of O2- release from LPS-primed macrophages, but heat killing or opsonization of M. lepraemurium had no effect on release of O2- from unprimed macrophages. The results suggest that M. lepraemurium is taken into macrophages by a mechanism that bypasses the FcR and other receptors that are capable of triggering the production of O2-.

Mycobacterium lepraemurium activates macrophages but fails to trigger release of superoxide anion

Mycobacterium lepraemurium failed to stimulate a normal respiratory burst when presented to mouse peritoneal or bone marrow macrophages. By comparison, Mycobacterium bovis (strain Bacillus Calmette-Guerin) or Saccharomyces cerevisiae, as expected, stimulated macrophages to release a large amount of superoxide anion (O2-). M. lepraemurium did not interfere with the response to yeast when both microbes were added together to macrophages. The low release of O2- induced by M. lepraemurium was not due to failure of M. lepraemurium to activate or prime macrophages, because exposure of macrophages to M. lepraemurium caused the expected enhancement of O2- release when the macrophages were stimulated by PMA. Similarly, macrophages taken from mice infected with M. lepraemurium were activated, as indicated by high PMA-stimulated O2- release. Macrophages primed in vitro by exposure to Escherichia coli LPS for 24 h did show a moderate O2- response when stimulated by M. lepraemurium, but macrophages primed by exposure to IFN-gamma muramyl dipeptide, or M. lepraemurium showed a weak response when subsequently challenged with M. lepraemurium. The priming effect of M. lepraemurium or LPS decreased substantially after macrophages were cultured in fresh medium for 24 h. Heat killing or opsonization of M. lepraemurium caused the M. lepraemurium to stimulate a high amount of O2- release from LPS-primed macrophages, but heat killing or opsonization of M. lepraemurium had no effect on release of O2- from unprimed macrophages. The results suggest that M. lepraemurium is taken into macrophages by a mechanism that bypasses the FcR and other receptors that are capable of triggering the production of O2-.

Reduction of tellurite and deesterification of fluorescein diacetate are not well correlated with the viability of mycobacteria

Both Mycobacterium leprae and M. lepraemurium (MLM) were capable of reducing tellurium as tellurite ion (Te4+) to elemental tellurium (Te), seen by electron microscopy as fine crystals within the bacterial cells. There appeared to be close correspondence between the capacity to reduce tellurite, bright green fluorescence after staining with fluorescein diacetate (FDA) and the ability of M. smegmatis to multiply in culture. Likewise, there appeared to be correspondence between tellurite reduction and fluorescence after FDA staining for MLM subjected to prolonged storage in the cold or to heating at 70 degrees C. However, correspondence with tellurite-reduction or fluorescence after FDA staining was not observed when death of MLM occurred in vivo.

Discrepancy in assessment of phagosome-lysosome fusion with two lysosomal markers in murine macrophages infected with Candida albicans

Phagosome-lysosome fusion (P-LF) was studied in cultured mouse resident peritoneal macrophages after phagocytosis of Candida albicans. The macrophages were labeled with acridine orange (AO), the electronopaque colloidal Thorotrast, or both markers. After phagocytosis of heat-killed C. albicans, both markers were delivered to more than 95% of phagosomes. After ingestion of viable C. albicans by labeled cells, delivery of AO to phagosomes was highly suppressed (90%), and yet Thorotrast delivery was almost universal. After phagocytosis and 60 min of incubation, about 10 to 20% of the yeasts were killed, and a similar fraction of phagosomes was stained by the fluorescent marker. The evidence from Thorotrast transfer and assessment of yeast viability indicates that C. albicans largely resists intracellular killing by resident macrophages in the face of entirely uninhibited P-LF. We infer that AO must transfer to nearly all of the phagosomes but that it is evidently recognizable only in those in which the yeasts have been killed or possibly severely injured. This conclusion constitutes yet another limitation in the usefulness of AO for studying P-LF.

Death of Mycobacterium lepraemurium after multiplication in CBA, BALB/c and nude mice

The unexpected death of Mycobacterium lepraemurium in the course of systemic infection of mice, previously noted in the spleens of CBA mice, has been demonstrated in the spleens of BALB/c nu/+ and BALB/c nu/nu mice and also in the livers and other organs of mice of all three strains. That the same phenomenon was observed in nu/nu mice indicates that the mechanism of bacterial death does not involve a T-lymphocyte-mediated cellular immune response on the part of the mice.

Epispadias with complete prepuce and phimosis in a neonate

A rare type of epispadias in a neonate is described in which a complete phimotic prepuce was present. In this situation, the accurate diagnosis is very difficult and may be easily overlooked in the neonatal period. The broad, spadelike glans, the dorsally directed prepucial opening, and the urinary stream are signs previously described. The special shape of the raphe penis and the depression between the corpora cavernosa felt by palpation of the glans are useful new clinical signs to suspect this type of epispadias.