Gut barrier defects, intestinal immune hyperactivation and enhanced lipid catabolism drive lethality in NGLY1-deficient Drosophila

Intestinal barrier dysfunction leads to inflammation and associated metabolic changes. However, the relative impact of gut bacteria versus non-bacterial insults on animal health in the context of barrier dysfunction is not well understood. Here, we establish that loss of Drosophila N-glycanase 1 (Pngl) in a specific intestinal cell type leads to gut barrier defects, causing starvation and JNK overactivation. These abnormalities, along with loss of Pngl in enterocytes and fat body, result in Foxo overactivation, leading to hyperactive innate immune response and lipid catabolism and thereby contributing to lethality. Germ-free rearing of Pngl mutants rescued their developmental delay but not lethality. However, raising Pngl mutants on isocaloric, fat-rich diets partially rescued lethality. Our data indicate that Pngl functions in Drosophila larvae to establish the gut barrier, and that the lethality caused by loss of Pngl is primarily mediated through non-bacterial induction of immune and metabolic abnormalities.

NGLY1 deficiency: a prospective natural history study

N-glycanase 1 (NGLY1) deficiency is a debilitating, ultra-rare autosomal recessive disorder caused by loss of function of NGLY1, a cytosolic enzyme that deglycosylates other proteins. It is characterized by severe global developmental delay and/or intellectual disability, hyperkinetic movement disorder, transient elevation of transaminases, (hypo)alacrima and progressive, diffuse, length-dependent sensorimotor polyneuropathy. A prospective natural history study (NHS) was conducted to elucidate clinical features and disease course. Twenty-nine participants were enrolled (15 onsite, 14 remotely) and followed for up to 32 months, representing ~29% of the ~100 patients identified worldwide. Participants exhibited profound developmental delays, with almost all developmental quotients below 20 on the Mullen Scales of Early Learning, well below the normative score of 100. Increased difficulties with sitting and standing suggested decline in motor function over time. Most patients presented with (hypo)alacrima and reduced sweat response. Pediatric quality of life was poor except for emotional function. Language/communication and motor skill problems including hand use were reported by caregivers as the most bothersome symptoms. Levels of the substrate biomarker, GlcNAc-Asn (aspartylglucosamine; GNA), were consistently elevated in all participants over time, independent of age. Liver enzymes were elevated for some participants but improved especially in younger patients and did not reach levels indicating severe liver disease. Three participants died during the study period. Data from this NHS informs selection of endpoints and assessments for future clinical trials for NGLY1 deficiency interventions. Potential endpoints include GNA biomarker levels, neurocognitive assessments, autonomic and motor function (particularly hand use), (hypo)alacrima and quality of life.

Gut barrier defects, increased intestinal innate immune response, and enhanced lipid catabolism drive lethality in N -glycanase 1 deficient Drosophila

Intestinal barrier dysfunction leads to inflammation and associated metabolic changes. However, the relative impact of infectious versus non-infectious mechanisms on animal health in the context of barrier dysfunction is not well understood. Here, we establish that loss of Drosophila N -glycanase 1 (Pngl) leads to gut barrier defects, which cause starvation and increased JNK activity. These defects result in Foxo overactivation, which induces a hyperactive innate immune response and lipid catabolism, thereby contributing to lethality associated with loss of Pngl . Notably, germ-free rearing of Pngl mutants did not rescue lethality. In contrast, raising Pngl mutants on isocaloric, fat-rich diets improved animal survival in a dosage-dependent manner. Our data indicate that Pngl functions in Drosophila larvae to establish the gut barrier, and that the immune and metabolic consequences of loss of Pngl are primarily mediated through non-infectious mechanisms.

AAV9-NGLY1 gene replacement therapy improves phenotypic and biomarker endpoints in a rat model of NGLY1 Deficiency

N-glycanase 1 (NGLY1) Deficiency is a progressive, ultra-rare, autosomal recessive disorder with no approved therapy and five core clinical features: severe global developmental delay, hyperkinetic movement disorder, elevated liver transaminases, alacrima, and peripheral neuropathy. Here, we confirmed and characterized the Ngly1 ^{-/- /} rat as a relevant disease model. GS-100, a gene therapy candidate, is a recombinant, single-stranded adeno-associated virus (AAV) 9 vector designed to deliver a functional copy of the human NGLY1 gene. Using the Ngly1 ^-/- rat, we tested different administration routes for GS-100: intracerebroventricular (ICV), intravenous (IV), or the dual route (IV + ICV). ICV and IV + ICV administration resulted in widespread biodistribution of human NGLY1 DNA and corresponding mRNA and protein expression in CNS tissues. GS-100 delivered by ICV or IV + ICV significantly reduced levels of the substrate biomarker N-acetylglucosamine-asparagine (GlcNAc-Asn or GNA) in CSF and brain tissue compared with untreated Ngly1^-/- rats. ICV and IV + ICV administration of GS-100 resulted in behavioral improvements in rotarod and rearing tests, whereas IV-only administration did not. IV + ICV did not provide additional benefit compared with ICV administration alone. These data provide evidence that GS-100 could be an effective therapy for NGLY1 Deficiency using the ICV route of administration.

Patient-derived gene and protein expression signatures of NGLY1 deficiency

N-Glycanase 1 (NGLY1) deficiency is a rare and complex genetic disorder. Although recent studies have shed light on the molecular underpinnings of NGLY1 deficiency, a systematic characterization of gene and protein expression changes in patient-derived cells has been lacking. Here, we performed RNA-sequencing and mass spectrometry to determine the transcriptomes and proteomes of 66 cell lines representing 4 different cell types derived from 14 NGLY1 deficient patients and 17 controls. Although NGLY1 protein levels were up to 9.5-fold downregulated in patients compared to parents, residual and likely non-functional NGLY1 protein was detectable in all patient-derived lymphoblastoid cell lines. Consistent with the role of NGLY1 as a regulator of the transcription factor Nrf1, we observed a cell type-independent downregulation of proteasomal genes in NGLY1 deficient cells. In contrast, genes involved in ribosome biogenesis and mRNA processing were upregulated in multiple cell types. In addition, we observed cell type-specific effects. For example, genes and proteins involved in glutathione synthesis, such as the glutamate-cysteine ligase subunits GCLC and GCLM, were downregulated specifically in lymphoblastoid cells. We provide a web application that enables access to all results generated in this study at https://apps.embl.de/ngly1browser. This resource will guide future studies of NGLY1 deficiency in directions that are most relevant to patients.

GlcNAc-Asn (GNA) is a biomarker for NGLY1 deficiency

Substrate-derived biomarkers are necessary in slowly progressing monogenetic diseases caused by single-enzyme deficiencies to identify affected patients and serve as surrogate markers for therapy response. N-glycanase 1 (NGLY1) deficiency is an ultra-rare autosomal recessive disorder characterized by developmental delay, peripheral neuropathy, elevated liver transaminases, hyperkinetic movement disorder and (hypo)-alacrima. We demonstrate that N-acetylglucosamine-asparagine (GlcNAc-Asn; GNA), is the analyte most closely associated with NGLY1 deficiency, showing consistent separation in levels between patients and controls. GNA accumulation is directly linked to the absence of functional NGLY1, presenting strong potential for its use as a biomarker. In agreement, a quantitative liquid chromatography with tandem mass spectrometry assay, developed to assess GNA from 3 to 3000 ng/ml, showed that it is conserved as a marker for loss of NGLY1 function in NGLY1-deficient cell lines, rodents (urine, cerebrospinal fluid, plasma and tissues) and patients (plasma and urine). Elevated GNA levels differentiate patients from controls, are stable over time and correlate with changes in NGLY1 activity. GNA as a biomarker has the potential to identify and validate patients with NGLY1 deficiency, act as a direct pharmacodynamic marker and serve as a potential surrogate endpoint in clinical trials.

Loss of N-Glycanase 1 Alters Transcriptional and Translational Regulation in K562 Cell Lines

N-Glycanase 1 (NGLY1) deficiency is an ultra-rare, complex and devastating neuromuscular disease. Patients display multi-organ symptoms including developmental delays, movement disorders, seizures, constipation and lack of tear production. NGLY1 is a deglycosylating protein involved in the degradation of misfolded proteins retrotranslocated from the endoplasmic reticulum (ER). NGLY1-deficient cells have been reported to exhibit decreased deglycosylation activity and an increased sensitivity to proteasome inhibitors. We show that the loss of NGLY1 causes substantial changes in the RNA and protein landscape of K562 cells and results in downregulation of proteasomal subunits, consistent with its processing of the transcription factor NFE2L1. We employed the CMap database to predict compounds that can modulate NGLY1 activity. Utilizing our robust K562 screening system, we demonstrate that the compound NVP-BEZ235 (Dactosilib) promotes degradation of NGLY1-dependent substrates, concurrent with increased autophagic flux, suggesting that stimulating autophagy may assist in clearing aberrant substrates during NGLY1 deficiency.

Evolthon: A community endeavor to evolve lab evolution

In experimental evolution, scientists evolve organisms in the lab, typically by challenging them to new environmental conditions. How best to evolve a desired trait? Should the challenge be applied abruptly, gradually, periodically, sporadically? Should one apply chemical mutagenesis, and do strains with high innate mutation rate evolve faster? What are ideal population sizes of evolving populations? There are endless strategies, beyond those that can be exposed by individual labs. We therefore arranged a community challenge, Evolthon, in which students and scientists from different labs were asked to evolve Escherichia coli or Saccharomyces cerevisiae for an abiotic stress—low temperature. About 30 participants from around the world explored diverse environmental and genetic regimes of evolution. After a period of evolution in each lab, all strains of each species were competed with one another. In yeast, the most successful strategies were those that used mating, underscoring the importance of sex in evolution. In bacteria, the fittest strain used a strategy based on exploration of different mutation rates. Different strategies displayed variable levels of performance and stability across additional challenges and conditions. This study therefore uncovers principles of effective experimental evolutionary regimens and might prove useful also for biotechnological developments of new strains and for understanding natural strategies in evolutionary arms races between species. Evolthon constitutes a model for community-based scientific exploration that encourages creativity and cooperation.

This Community Page article describes Evolthon; a first-of-its-kind community-based effort, involving about 30 participant labs around the world, aiming to explore the best strategy for evolving microorganisms to cope with an environmental challenge.

Inhibition of NGLY1 Inactivates the Transcription Factor Nrf1 and Potentiates Proteasome Inhibitor Cytotoxicity

Proteasome inhibitors are used to treat blood cancers such as multiple myeloma (MM) and mantle cell lymphoma. The efficacy of these drugs is frequently undermined by acquired resistance. One mechanism of proteasome inhibitor resistance may involve the transcription factor Nuclear Factor, Erythroid 2 Like 1 (NFE2L1, also referred to as Nrf1), which responds to proteasome insufficiency or pharmacological inhibition by upregulating proteasome subunit gene expression. This "bounce-back" response is achieved through a unique mechanism. Nrf1 is constitutively translocated into the ER lumen, N-glycosylated, and then targeted for proteasomal degradation via the ER-associated degradation (ERAD) pathway. Proteasome inhibition leads to accumulation of cytosolic Nrf1, which is then processed to form the active transcription factor. Here we show that the cytosolic enzyme N-glycanase 1 (NGLY1, the human PNGase) is essential for Nrf1 activation in response to proteasome inhibition. Chemical or genetic disruption of NGLY1 activity results in the accumulation of misprocessed Nrf1 that is largely excluded from the nucleus. Under these conditions, Nrf1 is inactive in regulating proteasome subunit gene expression in response to proteasome inhibition. Through a small molecule screen, we identified a cell-active NGLY1 inhibitor that disrupts the processing and function of Nrf1. The compound potentiates the cytotoxicity of carfilzomib, a clinically used proteasome inhibitor, against MM and T cell-derived acute lymphoblastic leukemia (T-ALL) cell lines. Thus, NGLY1 inhibition prevents Nrf1 activation and represents a new therapeutic approach for cancers that depend on proteasome homeostasis.

The Silent Sway of Splicing by Synonymous Substitutions

Alternative splicing diversifies mRNA transcripts in human cells. This sequence-driven process can be influenced greatly by mutations, even those that do not change the protein coding potential of the transcript. Synonymous mutations have been shown to alter gene expression through modulation of splicing, mRNA stability, and translation. Using a synonymous position mutation library in SMN1 exon 7, we show that 23% of synonymous mutations across the exon decrease exon inclusion, suggesting that nucleotide identity across the entire exon has been evolutionarily optimized to support a particular exon inclusion level. Although phylogenetic conservation scores are insufficient to identify synonymous positions important for exon inclusion, an alignment of organisms filtered based on similar exon/intron architecture is highly successful. Although many of the splicing neutral mutations are observed to occur, none of the exon inclusion reducing mutants was found in the filtered alignment. Using the modified phylogenetic comparison as an approach to evaluate the impact on pre-mRNA splicing suggests that up to 45% of synonymous SNPs are likely to alter pre-mRNA splicing. These results demonstrate that coding and pre-mRNA splicing pressures co-evolve and that a modified phylogenetic comparison based on the exon/intron architecture is a useful tool in identifying splice altering SNPs.

In vitro assay of pre-mRNA splicing in mammalian nuclear extract

The in vitro splicing assay is a valuable technique that can be used to study the mechanism and machinery involved in the splicing process. The ability to investigate various aspects of splicing and alternative splicing appears to be endless due to the flexibility of this assay. Here, we describe the tools and techniques necessary to carry out an in vitro splicing assay. Through the use of radiolabeled pre-mRNA and crude nuclear extract, spliced mRNAs can be purified and visualized by autoradiography for downstream analysis.

Position-dependent splicing activation and repression by SR and hnRNP proteins rely on common mechanisms

Alternative splicing is regulated by splicing factors that modulate splice site selection. In some cases, however, splicing factors show antagonistic activities by either activating or repressing splicing. Here, we show that these opposing outcomes are based on their binding location relative to regulated 5' splice sites. SR proteins enhance splicing only when they are recruited to the exon. However, they interfere with splicing by simply relocating them to the opposite intronic side of the splice site. hnRNP splicing factors display analogous opposing activities, but in a reversed position dependence. Activation by SR or hnRNP proteins increases splice site recognition at the earliest steps of exon definition, whereas splicing repression promotes the assembly of nonproductive complexes that arrest spliceosome assembly prior to splice site pairing. Thus, SR and hnRNP splicing factors exploit similar mechanisms to positively or negatively influence splice site selection.

G Run-mediated recognition of proteolipid protein and DM20 5' splice sites by U1 small nuclear RNA is regulated by context and proximity to the splice site

Highly conserved G runs, G1M2 and ISE, regulate the proteolipid protein (PLP)/DM20 ratio. We have investigated recruitment of U1 small nuclear ribonuclear protein (snRNP) by G1M2 and ISE and examined the effect of splice site strength, distance, and context on G run function. G1M2 is necessary for initial recruitment of U1snRNP to the DM20 5' splice site independent of the strength of the splice site. G1M2 regulates E complex formation and supports DM20 splicing when functional U1snRNP is reduced. By contrast, the ISE is not required for the initial recruitment of U1snRNP to the PLP 5' splice site. However, in close proximity to either the DM20 or the PLP 5' splice site, the ISE recruits U1snRNP to both splice sites. The ISE enhances DM20 splicing, whereas close to the PLP 5' splice site, it inhibits PLP splicing. Splicing enhancement and inhibition are mediated by heterogeneous nuclear ribonuclear protein (hnRNP)H/F. The data show that recognition of the DM20 5' splice site depends on G run-mediated recruitment of U1snRNA, whereas a complex interaction between the ISE G runs, context and position determines the functional outcome on splicing. The data suggest that different mechanisms underlie G run-mediated recognition of 5' splice sites and that context and position play a critical role.

Z = 50 shell gap near 100Sn from intermediate-energy Coulomb excitations in even-mass 106-112Sn isotopes

Rare isotope beams of neutron-deficient 106,108,110Sn from the fragmentation of 124Xe were employed in an intermediate-energy Coulomb excitation experiment. The measured B(E2,0(1)(+)-->2(1)(+)) values for 108Sn and 110Sn and the results obtained for the 106Sn show that the transition strengths for these nuclei are larger than predicted by current state-of-the-art shell-model calculations. This discrepancy might be explained by contributions of the protons from within the Z = 50 shell to the structure of low-energy excited states in this region.

Measurement of excited states in (40)Si and evidence for weakening of the N=28 shell gap

Excited states in (40)Si have been established by detecting gamma rays coincident with inelastic scattering and nucleon removal reactions on a liquid hydrogen target. The low excitation energy, 986(5) keV, of the 2(1)(+) state provides evidence of a weakening in the N=28 shell closure in a neutron-rich nucleus devoid of deformation-driving proton collectivity.

Probing shell structure and shape changes in neutron-rich sulfur isotopes through transient-field g-factor measurements on fast radioactive beams of 38S and 40S

The shell structure underlying shape changes in neutron-rich nuclei near N = 28 has been investigated by a novel application of the transient-field technique to measure the first-excited-state g factors in 38S and 40S produced as fast radioactive beams. There is a fine balance between proton and neutron contributions to the magnetic moments in both nuclei. The g factor of deformed 40S does not resemble that of a conventional collective nucleus because spin contributions are more important than usual.

Quadrupole deformation of the self-conjugate nucleus 72Kr

We report on the first determination of the absolute B(E2;0+(1)-->2+(1)) excitation strength in the N=Z nucleus 72Kr. 72Kr is the heaviest N=Z nucleus for which this quantity has been measured and provides a benchmark in a region of the nuclear chart dominated by rapidly changing deformations and shapes mediated by the interplay of strongly oblate and prolate-driving orbitals. The deduced quadrupole deformation strength is in agreement with a variety of self-consistent models that predict an oblate shape for the ground state of 72Kr. Large-scale shell-model Monte Carlo calculations reproduce the experimental B(E2) value and link the result to the occupation of the deformation-driving g9/2 orbit.

‘Magic’ nucleus 42Si

Nuclear shell structures--the distribution of the quantum states of individual protons and neutrons--provide one of our most important guides for understanding the stability of atomic nuclei. Nuclei with 'magic numbers' of protons and/or neutrons (corresponding to closed shells of strongly bound nucleons) are particularly stable. Whether the major shell closures and magic numbers change in very neutron-rich nuclei (potentially causing shape deformations) is a fundamental, and at present open, question. A unique opportunity to study these shell effects is offered by the 42Si nucleus, which has 28 neutrons--a magic number in stable nuclei--and 14 protons. This nucleus has a 12-neutron excess over the heaviest stable silicon nuclide, and has only one neutron fewer than the heaviest silicon nuclide observed so far. Here we report measurements of 42Si and two neighbouring nuclei using a technique involving one- and two-nucleon knockout from beams of exotic nuclei. We present strong evidence for a well-developed proton subshell closure at Z = 14 (14 protons), the near degeneracy of two different (s(1/2) and d(3/2)) proton orbits in the vicinity of 42Si, and a nearly spherical shape for 42Si.

29Na: defining the edge of the island of inversion for Z=11

The low-energy level structure of the exotic Na isotopes (28,29)Na has been investigated through beta-delayed gamma spectroscopy. The N=20 isotones for Z=10-12 are considered to belong to the "island of inversion" where intruder configurations dominate the ground state wave function. However, it is an open question as to where and how the transition from normal to intruder dominated configurations happens in an isotopic chain. The present work, which presents the first detailed spectroscopy of (28,29)Na, clearly demonstrates that such a transition in the Na isotopes occurs between 28Na (N=17) and 29Na (N=18), supporting the smaller N=20 shell gap in neutron-rich sd shell nuclei. The evidence for inverted shell structure is found in beta-decay branching ratios, intruder dominated spectroscopy of low-lying states, and shell model analysis.

Half-life of the doubly magic r-process nucleus 78Ni

Nuclei with magic numbers serve as important benchmarks in nuclear theory. In addition, neutron-rich nuclei play an important role in the astrophysical rapid neutron-capture process (r process). 78Ni is the only doubly magic nucleus that is also an important waiting point in the r process, and serves as a major bottleneck in the synthesis of heavier elements. The half-life of 78Ni has been experimentally deduced for the first time at the Coupled Cyclotron Facility of the National Superconducting Cyclotron Laboratory at Michigan State University, and was found to be 110(+100)(-60) ms. In the same experiment, a first half-life was deduced for 77Ni of 128(+27)(-33) ms, and more precise half-lives were deduced for 75Ni and 76Ni of 344(+20)(-24) ms and 238(+15)(-18) ms, respectively.

Reduced occupancy of the deeply bound 0d(5/2) neutron state in 32Ar

The 9Be(32Ar, 31Ar)X reaction, leading to the 5/2+ ground state of a nucleus at the proton drip line, has a cross section of 10.4(13) mb at a beam energy of 65.1 MeV/nucleon. This translates into a spectroscopic factor that is only 24(3)% of that predicted by the many-body shell-model theory. We introduce refinements to the eikonal reaction theory used to extract the spectroscopic factor to clarify that this very strong reduction represents an effect of nuclear structure. We suggest that it reflects correlation effects linked to the high neutron separation energy (22.0 MeV) for this state.

New approach for measuring properties of rp-process nuclei

A new experimental approach was developed that can reduce the uncertainties in astrophysical rapid proton capture (rp) process calculations due to nuclear data. This approach utilizes neutron removal from a radioactive ion beam to populate the nuclear states of interest. Excited states were deduced by the gamma-decay spectra measured in a semiconductor Ge-detector array. In the first case studied, 33Ar, excited states were measured with uncertainties of several keV. The 2 orders of magnitude improvement in the uncertainty of the level energies resulted in a 3 orders of magnitude improvement in the uncertainty of the calculated 32Cl(p,gamma)33Ar rate that is critical to the modeling of the rp process. This approach has the potential to measure key properties of almost all interesting nuclei on the rp-process path.

Unambiguous identification of three beta-decaying isomers in 70Cu

Using resonant laser ionization, beta-decay studies, and for the first time mass measurements, three beta-decaying states have been unambiguously identified in 70Cu. A mass excess of -62 976.1(1.6) keV and a half-life of 44.5(2) s for the (6-) ground state have been determined. The level energies of the (3-) isomer at 101.1(3) keV with T(1/2)=33(2) s and the 1+ isomer at 242.4(3) keV with T(1/2)=6.6(2) s are confirmed by high-precision mass measurements. The low-lying levels of 70Cu populated in the decay of 70Ni and in transfer reactions compare well with large-scale shell-model calculations, and the wave functions appear to be dominated by one proton-one neutron configurations outside the closed Z=28 shell and N=40 subshell. This does not apply to the 1+ state at 1980 keV which exhibits a particular feeding and deexcitation pattern not reproduced by the shell-model calculations.

Lowest excitations in 56Ti and the predicted N=34 shell closure

Recent experimental characterization of the subshell closure at N=32 in the Ca, Ti, and Cr isotones has stimulated shell-model calculations that indicated the possibility that the N=34 isotones of these same elements could exhibit characteristics of a shell closure, namely, a high energy for the first excited 2(+) level. To that end, we have studied the decay of 56Sc produced in fragmentation reactions and identified new gamma rays in the daughter N=34 isotone 56Ti. The first 2(+) level is found at an energy of 1127 keV, well below the expected position that would indicate the presence of an N=34 shell closure in 56Ti.

New direct reaction: two-proton knockout from neutron-rich nuclei

The reaction 9Be(28Mg,26Ne+gamma)X has been studied at 82 MeV/nucleon together with two similar cases, 30Mg and 34Si. Strong evidence that the reactions are direct is offered by the parallel-momentum distributions of the reaction residues and by the inclusive cross sections. The pattern of the partial cross sections for 28Mg suggests the presence of correlations. A preliminary theoretical discussion based on eikonal reaction theory and the many-body shell model is presented. The reaction holds great promise for the study of neutron-rich nuclei.

Chemical components of shredded paper insulation: a preliminary study

We conducted an evaluation of shredded paper insulation to identify potentially toxic components. The study was to provide a preliminary characterization of a few samples of insulation currently in use. The following samples were analyzed: previously produced insulation (PPI) containing fire retardants, shredded recycled paper (PPI feedstock), freshly produced insulation (FPI), and insulation which had been installed in a residence (II). Volatile constituents were analyzed by GC-MS from headspace air of samples held at room temperature or heated to 90 degrees C. Extractable constituents were sampled by extracting with methylene chloride, and analyzing by GC-MS. Formaldehyde analysis was done according to EPA Method TO11. Headspace air at room temperature contained no detectable quantities of volatile constituents for any sample measured. In headspace air at 90 degrees C, only PPI contained traces of aliphatic and aromatic hydrocarbons and higher aldehydes, and FPI traces of toluene. Extracts of PPI contained traces of octadecadienoic acid methyl ester and aliphatic and aromatic hydrocarbons and higher aldehydes. Extracts of PPI feedstock contained traces of a substituted cyclohexenecarboxylic acid. FPI contained extractable diethyl phthalate (30-50 micrograms/g). Extracts of II contained traces of methyl palmitate, an octadecenoic acid methyl ester, and a phthalate plasticizer. No formaldehyde was detected. PPI was composed of approximately 98 percent paper fiber and 2 percent pre-gelatinized starch. PPI samples agglomerated together with less than 0.01 percent separating from clumps as fine dust. Boron and sodium were expected and confirmed because they were added to PPI and FPI as fire retardants. Chromium, copper, iron, potassium, magnesium, manganese, phosphorus, and silicon were present at detectable concentrations. Study calculations indicate that an occupant would have to completely consume all the fine particles produced from 3.3 kg of insulation per day to have an intake of boron equivalent to the EPA RfD. No other constituent appeared to be present even close to toxicologically relevant amounts.

Fulminant disseminated toxoplasmosis in an HIV patient

Disseminated toxoplasmosis in AIDS is a rare condition. We present an unusual case of a fulminant form of disseminated toxoplasmosis in a young male homosexual. He was a 30-year-old HIV-positive (diagnosed 4 months earlier), admitted with a 5-day history of diarrhea, vomiting, fever, and cough. He had been generally healthy except for an 8-week history of weight loss and malaise. On admission, except for a temperature of 37.6 degrees C, the physical examination was normal. He was treated symptomatically. Four days after admission he suddenly became short of breath. Despite intensive management, he continued to deteriorate and expired 6 h later. Postmortem examination revealed disseminated toxoplasmosis involving the heart, lungs, brain, stomach, small intestine, and colon. This is an unusual presentation of disseminated toxoplasmosis because of its rapid course with no prior indication of infection. To our knowledge, such an atypical and rapid downhill course of toxoplasmosis (with minimal clinical and laboratory features) has not been reported previously. Increased awareness of this infection in all HIV patients and its possibly rapid course is needed.

Comparison of serum CA 19-9 and CEA levels in a population at high risk for colorectal cancer

The sera of 563 patients who underwent colonoscopy were assayed for glycolipid antigen CA 19-9 and CEA. These patients represented a broad spectrum of clinical diseases ranging from advanced metastatic cancer of the colon, pancreas, or stomach to those with negative colonoscopic examination. Sensitivity and specificity for CA 19-9 and CEA were calculated using the following clinical definitions. Malignant or pre-malignant disease was defined as colon, pancreatic or stomach carcinoma, stomach dysplasia, atypical adenomatous polyp, atypical villous adenoma, carcinoma in situ and carcinoma in an adenomatous polyp. When the normal group included patients with adenomatous polyp, hyperplastic adenoma, inflammatory disease and patients with no disease apparent, the sensitivity and specificity for CA 19-9 was 23% and 96%, and for CEA, 23% and 95%, respectively. When adenomatous polyp patients were placed in the malignant or pre-malignant disease group, the sensitivity and specificity for CA 19-9 was 8% and 96%, and for CEA, 11% and 95%, respectively. When comparing CA 19-9 and CEA in colorectal carcinoma, the percent positivity of the CEA assay was equal to, or better than, CA 19-9 in all Dukes' stages. In pancreatic carcinomas CA 19-9 showed better diagnostic performance than CEA.

Distribution of cyclosporine in blood of a renal-transplant recipient with type V hyperlipoproteinemia

A patient with severe type V hyperlipoproteinemia and chronic end-stage renal disease received a renal transplant and therapy with cyclosporine. Concentrations of the drug in plasma as determined by liquid chromatography appeared extraordinarily high for the dose ingested. When we measured the drug in the plasma, plasma cleared by ultracentrifugation, leukocytes, erythrocytes, and whole blood, we found that the high concentrations of cyclosporine were associated with the chylomicrons that always were present in this patient's blood. Cyclosporine added directly to this patient's plasma was less associated with the plasma lipids. Isolated lymphocytes and kidney slices incubated with plasma from this patient bound no more drug than when incubated with nonhyperlipemic plasma containing cyclosporine at a normal therapeutic concentration. We conclude that the cyclosporine associated with the chylomicrons in this patient was not biologically available to either lymphocytes or kidney tissue. We strongly recommend the use of chylomicron-cleared plasma for therapeutic drug monitoring of cyclosporine in type V hyperlipoproteinemic patients.

Distribution of cyclosporine in blood of a renal-transplant recipient with type V hyperlipoproteinemia

A patient with severe type V hyperlipoproteinemia and chronic end-stage renal disease received a renal transplant and therapy with cyclosporine. Concentrations of the drug in plasma as determined by liquid chromatography appeared extraordinarily high for the dose ingested. When we measured the drug in the plasma, plasma cleared by ultracentrifugation, leukocytes, erythrocytes, and whole blood, we found that the high concentrations of cyclosporine were associated with the chylomicrons that always were present in this patient's blood. Cyclosporine added directly to this patient's plasma was less associated with the plasma lipids. Isolated lymphocytes and kidney slices incubated with plasma from this patient bound no more drug than when incubated with nonhyperlipemic plasma containing cyclosporine at a normal therapeutic concentration. We conclude that the cyclosporine associated with the chylomicrons in this patient was not biologically available to either lymphocytes or kidney tissue. We strongly recommend the use of chylomicron-cleared plasma for therapeutic drug monitoring of cyclosporine in type V hyperlipoproteinemic patients.

The role of the chimpanzee in the evaluation of the risk of foreign chemicals to man

Various species of laboratory animals are used to evaluate the efficacy and safety of drugs in man. However, the extrapolation of data from animals to man is often complicated by species differences in the disposition of foreign chemicals. The findings of comparative metabolism studies are used to illustrate species differences in metabolic pathways, rates of biotransformation, kinetics, and excretion routes. Biochemical and structural consequences of the significant differences in enzyme induction between rodents and primate species are discussed. Among the primates, the chimpanzee has been shown to be the most closely related to man not only in the disposition of xenobiotics, but also in the aspects of endocrinology, serology, and immunology. It would, therefore, be the best possible model to predict the fate and effects of foreign chemicals in man. Due to the limited availability of chimpanzees, however, they can only be used for the evaluation of the most critical chemicals and drugs. Comparative metabolism and disposition studies, e.g., of compounds representative of classes of chemicals in chimpanzees and other animals. Only when the pertinent differences between the selected test species and man are known can correct extrapolations to man be made.

Asymmetric septal hypertrophy of the heart. New findings concerning the possible etiology of sudden deaths in five males

This report describes certain interesting postmortem findings in the hearts of five subjects who died suddenly, silently, and unexpectedly, and in whom the only significant abnormality at autopsy was asymmetric septal hypertrophy (ASH) of the heart. Deep clefts, cystic faults, and dilated vascular channels were not only seen within the septal myocardium in all the hearts, but also within the left ventricular free walls of two hearts. The septal myocardium and the left ventricular free walls of two hearts and the A-V node and His bundle of one heart demonstrated mural and luminal thrombi of several dilated vascular channels. In another heart, foci of cardiocytic myofibrillar degeneration were seen, especially close to narrowed small coronary vessels. Fetal dispersion and fibrosis of the A-V node and His bundle were evident in one heart. These abnormalities in the conducting system and the ventricular myocardium suggest that the hearts of subjects with ASH are not only excellent anatomic substrates for lethal arrhythmias, but also are bound to be hemodynamically impaired. We believe that conditions such as hypoxia, increased oxygen demand by the heart or abnormal sympathetic stimulus may easily trigger fatal arrhythmias in such individuals, thereby causing sudden death.

A fatal maprotiline intoxication

A fatal maprotiline intoxication is presented. The postmortem anatomical and toxicologic findings are discussed, as is the mechanism of maprotiline toxicity. This report is, to the best of our knowledge, the sixth fatal maprotiline poisoning in the medical literature.

Testicular gonadal stromal (Sertoli cell) tumor

Eighty-one cases of testicular gonadal stromal tumor have been reported in the literature. An additional case is herein reported. The pathologic, immunohistologic, and histogenetic aspects are presented.

Invasive pituitary oncocytoma

A large invasive pituitary neoplasm, surgically resected by left frontotemporal craniotomy, and thought to represent "chromophobe" adenoma by light microscopy, exhibited ultrastructural features characteristic of oncocytoma. Electron microscopic and immunocytochemical studies showed that the tumor did not possess enhanced secretory activity. The indispensable role of electron microscopy in the identification of this rare neoplasm and especially in the classification of all pituitary tumors is emphasized.

Marked concomittant elevations in serum creatine kinase and lactic dehydrogenase in a patient with bowel necrosis

We report what we believe to be the first proven marked concomittant elevations in serum creatine kinase (CK) and lactic dehydrogenase (LD) in a patient with bowel necrosis. The necrosis was the result of infarction secondary to bowel strangulation. The serum from this patient showed elevation of total CK activity resulting from an abnormal amount of MM, MB, and BB isoenzymes with LD2, LD3, and LD5 yielding 18 per cent, 19 per cent, and 29 per cent, respectively, of the total LD activity.

Mass spectrometry and stability of t-butyldimethylsilylethers of some estrogens and androstanes

In addition to using radioimmunoassays for the determination of estrogens and other steroids, the possibility of using mass fragmentography for analysis was investigated. t-Butyldimethylsilyl chloride was selected as a reagent for derivatisation because it forms rather stable silylethers. In all the mass-spectra obrained from the steroid derivatives, one pronounced peak suitable for mass fragmentography was always present. Some of the spectra of the investigated estrogens, as well as testosterone, 3 alpha-hydroxy-5 alpha-androstan-17-one and 17 alpha-methyl-17 beta-hydroxy-5 alpha-androstan-3-one are discussed. The stability of various t-butyldimethylsilylethers and the rate of enolization of testosterone and progesterone in the presence of the silylation-agent under different conditions were established.