Redox regulation of m6A methyltransferase METTL3 in β-cells controls the innate immune response in type 1 diabetes

Type 1 diabetes (T1D) is characterized by the destruction of pancreatic β-cells. Several observations have renewed the interest in β-cell RNA sensors and editors. Here, we report that N6-methyladenosine (m6A) is an adaptive β-cell safeguard mechanism that controls the amplitude and duration of the antiviral innate immune response at T1D onset. m6A writer methyltransferase 3 (METTL3) levels increase drastically in β-cells at T1D onset but rapidly decline with disease progression. m6A sequencing revealed the m6A hypermethylation of several key innate immune mediators, including OAS1, OAS2, OAS3 and ADAR1 in human islets and EndoC-βH1 cells at T1D onset. METTL3 silencing enhanced 2'-5'-oligoadenylate synthetase levels by increasing its mRNA stability. Consistently, in vivo gene therapy to prolong Mettl3 overexpression specifically in β-cells delayed diabetes progression in the non-obese diabetic mouse model of T1D. Mechanistically, the accumulation of reactive oxygen species blocked upregulation of METTL3 in response to cytokines, while physiological levels of nitric oxide enhanced METTL3 levels and activity. Furthermore, we report that the cysteines in position C276 and C326 in the zinc finger domains of the METTL3 protein are sensitive to S-nitrosylation and are important to the METTL3-mediated regulation of oligoadenylate synthase mRNA stability in human β-cells. Collectively, we report that m6A regulates the innate immune response at the β-cell level during the onset of T1D in humans.

m 6 A mRNA Methylation Regulates Early Pancreatic β-Cell Differentiation

N 6 -methyladenosine (m 6 A) is the most abundant chemical modification in mRNA, and plays important roles in human and mouse embryonic stem cell pluripotency, maintenance, and differentiation. We have recently reported, for the first time, the role of m 6 A in the postnatal control of β-cell function in physiological states and in Type 1 and 2 Diabetes. However, the precise mechanisms by which m 6 A acts to regulate the development of human and mouse β-cells are unexplored. Here, we show that the m 6 A landscape is dynamic during human pancreas development, and that METTL14, one of the m 6 A writer complex proteins, is essential for the early differentiation of both human and mouse β-cells.

Redox Regulation of m 6 A Methyltransferase METTL3 in Human β-cells Controls the Innate Immune Response in Type 1 Diabetes

Type 1 Diabetes (T1D) is characterized by autoimmune-mediated destruction of insulin-producing β-cells. Several observations have renewed interest in the innate immune system as an initiator of the disease process against β-cells. Here, we show that N 6 -Methyladenosine (m 6 A) is an adaptive β-cell safeguard mechanism that accelerates mRNA decay of the 2'-5'-oligoadenylate synthetase (OAS) genes to control the antiviral innate immune response at T1D onset. m 6 A writer methyltransferase 3 (METTL3) levels increase drastically in human and mouse β-cells at T1D onset but rapidly decline with disease progression. Treatment of human islets and EndoC-βH1 cells with pro-inflammatory cytokines interleukin-1 β and interferon α mimicked the METTL3 upregulation seen at T1D onset. Furthermore, m 6 A-sequencing revealed the m 6 A hypermethylation of several key innate immune mediators including OAS1, OAS2, and OAS3 in human islets and EndoC-βH1 cells challenged with cytokines. METTL3 silencing in human pseudoislets or EndoC-βH1 cells enhanced OAS levels by increasing its mRNA stability upon cytokine challenge. Consistently, in vivo gene therapy, to prolong Mettl3 overexpression specifically in β-cells, delayed diabetes progression in the non-obese diabetic (NOD) mouse model of T1D by limiting the upregulation of Oas pointing to potential therapeutic relevance. Mechanistically, the accumulation of reactive oxygen species blocked METTL3 upregulation in response to cytokines, while physiological levels of nitric oxide promoted its expression in human islets. Furthermore, for the first time to our knowledge, we show that the cysteines in position C276 and C326 in the zinc finger domain of the METTL3 protein are sensitive to S-nitrosylation (SNO) and are significant for the METTL3 mediated regulation of OAS mRNA stability in human β-cells in response to cytokines. Collectively, we report that m 6 A regulates human and mouse β-cells to control the innate immune response during the onset of T1D and propose targeting METTL3 to prevent β-cell death in T1D.

Local Immunomodulatory Strategies to Prevent Allo-Rejection in Transplantation of Insulin-Producing Cells

Islet transplantation has shown promise as a curative therapy for type 1 diabetes (T1D). However, the side effects of systemic immunosuppression and limited long-term viability of engrafted islets, together with the scarcity of donor organs, highlight an urgent need for the development of new, improved, and safer cell-replacement strategies. Induction of local immunotolerance to prevent allo-rejection against islets and stem cell derived β cells has the potential to improve graft function and broaden the applicability of cellular therapy while minimizing adverse effects of systemic immunosuppression. In this mini review, recent developments in non-encapsulation, local immunomodulatory approaches for T1D cell replacement therapies, including islet/β cell modification, immunomodulatory biomaterial platforms, and co-transplantation of immunomodulatory cells are discussed. Key advantages and remaining challenges in translating such technologies to clinical settings are identified. Although many of the studies discussed are preliminary, the growing interest in the field has led to the exploration of new combinatorial strategies involving cellular engineering, immunotherapy, and novel biomaterials. Such interdisciplinary research will undoubtedly accelerate the development of therapies that can benefit the whole T1D population.

Parental metabolic syndrome epigenetically reprograms offspring hepatic lipid metabolism in mice

The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing worldwide. Although gene-environment interactions have been implicated in the etiology of several disorders, the impact of paternal and/or maternal metabolic syndrome on the clinical phenotypes of offspring and the underlying genetic and epigenetic contributors of NAFLD have not been fully explored. To this end, we used the liver-specific insulin receptor knockout (LIRKO) mouse, a unique nondietary model manifesting 3 hallmarks that confer high risk for the development of NAFLD: hyperglycemia, insulin resistance, and dyslipidemia. We report that parental metabolic syndrome epigenetically reprograms members of the TGF-β family, including neuronal regeneration-related protein (NREP) and growth differentiation factor 15 (GDF15). NREP and GDF15 modulate the expression of several genes involved in the regulation of hepatic lipid metabolism. In particular, NREP downregulation increases the protein abundance of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and ATP-citrate lyase (ACLY) in a TGF-β receptor/PI3K/protein kinase B-dependent manner, to regulate hepatic acetyl-CoA and cholesterol synthesis. Reduced hepatic expression of NREP in patients with NAFLD and substantial correlations between low serum NREP levels and the presence of steatosis and nonalcoholic steatohepatitis highlight the clinical translational relevance of our findings in the context of recent preclinical trials implicating ACLY in NAFLD progression.

m6A mRNA Methylation Regulates Human β-Cell Biology in Physiological States and in Type 2 Diabetes

The regulation of islet cell biology is critical for glucose homeostasis¹.N⁶ -methyladenosine (m⁶A) is the most abundant internal messenger RNA (mRNA) modification in mammals². Here we report that the m⁶A landscape segregates human type 2 diabetes (T2D) islets from controls significantly better than the transcriptome and that m⁶A is vital for β-cell biology. m⁶A-sequencing in human T2D islets reveals several hypomethylated transcripts involved in cell-cycle progression, insulin secretion, and the Insulin/IGF1-AKT-PDX1 pathway. Depletion of m⁶A levels in EndoC-βH1 induces cell-cycle arrest and impairs insulin secretion by decreasing AKT phosphorylation and PDX1 protein levels. β-cell specific Mettl14 knock-out mice, which display reduced m⁶A levels, mimic the islet phenotype in human T2D with early diabetes onset and mortality due to decreased β-cell proliferation and insulin degranulation. Our data underscore the significance of RNA methylation in regulating human β-cell biology, and provide a rationale for potential therapeutic targeting of m⁶A modulators to preserve β-cell survival and function in diabetes.

Nanotechnology in cell replacement therapies for type 1 diabetes

Islet transplantation is a promising long-term, compliance-free, complication-preventing treatment for type 1 diabetes. However, islet transplantation is currently limited to a narrow set of patients due to the shortage of donor islets and side effects from immunosuppression. Encapsulating cells in an immunoisolating membrane can allow for their transplantation without the need for immunosuppression. Alternatively, "open" systems may improve islet health and function by allowing vascular ingrowth at clinically attractive sites. Many processes that enable graft success in both approaches occur at the nanoscale level-in this review we thus consider nanotechnology in cell replacement therapies for type 1 diabetes. A variety of biomaterial-based strategies at the nanometer range have emerged to promote immune-isolation or modulation, proangiogenic, or insulinotropic effects. Additionally, coating islets with nano-thin polymer films has burgeoned as an islet protection modality. Materials approaches that utilize nanoscale features manipulate biology at the molecular scale, offering unique solutions to the enduring challenges of islet transplantation.

The Essential Role of Circulating Thyroglobulin in Maintaining Dominance of Natural Regulatory T Cell Function to Prevent Autoimmune Thyroiditis

Several key findings from the late 1960s to mid-1970s regarding thyroid hormone metabolism and circulating thyroglobulin composition converged with studies pertaining to the role of T lymphocytes in autoimmune thyroiditis. These studies cemented the foundation for subsequent investigations into the existence and antigenic specificity of thymus-derived natural regulatory T cells (nTregs). These nTregs prevented the development of autoimmune thyroiditis, despite the ever-present genetic predisposition, autoantigen (thyroglobulin), and thyroglobulin-reactive T cells. Guided by the hypothalamus-pituitary-thyroid axis as a fixed set-point regulator in thyroid hormone metabolism, we used a murine model and compared at key junctures the capacity of circulating thyroglobulin level (raised by thyroid-stimulating hormone or exogenous thyroglobulin administration) to strengthen self-tolerance and resist autoimmune thyroiditis. The findings clearly demonstrated an essential role for raised circulating thyroglobulin levels in maintaining the dominance of nTreg function and inhibiting thyroid autoimmunity. Subsequent identification of thyroglobulin-specific nTregs as CD4(+)CD25(+)Foxp3(+) in the early 2000s enabled the examination of probable mechanisms of nTreg function. We observed that whenever nTreg function was perturbed by immunotherapeutic measures, opportunistic autoimmune disorders invariably surfaced. This review highlights the step-wise progression of applying insights from endocrinologic and immunologic studies to advance our understanding of the clonal balance between natural regulatory and autoreactive T cells. Moreover, we focus on how tilting the balance in favor of maintaining peripheral tolerance could be achieved. Thus, murine autoimmune thyroiditis has served as a unique model capable of closely simulating natural physiologic conditions.

Clinical judgments of high-risk behavior during recovery

This study utilized focus group research to explore high-risk behavior during recovery from drugs and alcohol. Participants in the focus group were professional substance abuse counselors. The findings identified specific high-risk behaviors and began an exploration of the processes that support them. Specific information is included on such issues as causes, time frames, developmental issues, and other factors associated with high-risk behavior. Attention was paid to existential issues in recovery, as well as childhood factors such as sexual abuse. High-risk behavior was seen as a means to avoid the existential dilemma of continuing in recovery or returning to drug use and as a possible means to leave this crisis unresolved without actual relapse to drug use, or dealing with the issues of advancing in recovery.

Determination of drug-plasma protein binding using human serum albumin chromatographic column and multiple linear regression model

Reversible attachment to serum proteins plays a significant role in pharmacokinetics and pharmacodynamics, and a clear understanding of this process is fundamental in the development of the rational use of many therapeutics agents. Over the last few years, it has been demonstrated that immobilized human serum albumin (HSA) could be used to estimate plasma protein binding. A series of 40 structurally unrelated pharmaceutical compounds were chromatographed on an immobilized HSA column in order to construct a protein binding 'calibration curve' and multiple linear regression system. When studying the relationship between the chromatographic retention and the percentage of binding determined in vitro, a good correlation can be observed (r(2) = 0.799) using a wide variety of compounds with different binding affinities (from 0 to 99% binding). Using a quantitative structure-retention relationships (QSRR) approach to analysing chromatographic data, the correlation was improved compared to the traditional approach (r(2) = 0.824).

Metabolite profiling study of propranolol in rat using LC/MS/MS analysis

Metabolite profiling is one of the most challenging fields in applied mass spectrometry. Mass spectrometry was used to characterize the metabolites of propranolol, a beta-adrenergic receptor antagonist containing numerous oxidation sites. Propranolol is extensively metabolized, with most metabolites appearing in urine. Urine samples were collected from young adult male Sprague-Dawley rats. Structural identification of various metabolites was performed by LC/MS/MS, using a PE SCIEX triple quadrupole instrument (PE SCIEX API 3000). Metabolites were itemized using several LC/MS/MS techniques, including Q3 full scan and precursor and constant neutral loss experiments. A looped experiment technique revealed the presence of mono- and di-hydroxylated metabolites as well as regio isomers of hydroxy- and dihydroxy-propranolol glucuronides and propranolol glucuronic acid. Propranolol glucuronide was not observed, while the presence of dealkylated metabolites was suggested but not confirmed.

Nontreatment and aggressive narcotic therapy among hospitalized pancreatic cancer patients

OBJECTIVES

Strong feelings about patient autonomy as expressed in living wills, polls, and legislative referenda have been challenging the medical establishment to increase nontreatment, defined as foregoing a life-prolonging treatment, and even to provide treatments having life-shortening potential to selected patients. Because there are little data about the actual practice of these procedures, including aggressive narcotic therapy as defined herein, we studied the terminal management of 417 pancreatic cancer patients.

DESIGN AND PARTICIPANTS

The medical records of 417 residents of King County, Washington, who died of pancreatic cancer in the time periods 1959-1962, 1969-1972, and 1985-1990, were reviewed to study the frequency of, and risk factors for, end-of-life nontreatment decisions and aggressive narcotic therapy decisions, defined here as the decision to administer treatment doses of narcotics or major sedatives to already comatose patients within 4 hours of death.

RESULTS

Antibiotics were not provided to 71% of the 70 febrile patients (two readings >38.33-38.83 degrees C or one reading of 38.88 degrees C), intravenous fluid was not provided to 43% of 294 dehydrated patients (oral intake <500 mL/24 hours), transfusions were not provided to 39% of 57 severely anemic patients (hematocrit <20%), and laparotomy was not performed for 86% of 36 patients with abdominal emergencies (obstruction, bleeding, dehiscence). Also, 46% of the 118 patients who were comatose for at least 24 hours before death received aggressive narcotic therapy, as defined above. A total of 335 of the 417 patients had documentation of at least one of the above life-threatening conditions or were comatose for at least 24 hours before death, and 289 (86%) of these patients experienced nontreatment of one or more of these conditions or received aggressive narcotic therapy. Nontreatment decisions for febrile, dehydrated, or anemic patients tended to be more frequent if the patient was comatose (P=.004, .010, and .065, respectively), if there was a nontreatment statement in the medical record (P=.009, .035, and .001, respectively), or if the patient was described as terminal (P=.262, .029, and .002, respectively). Aggressive narcotic therapy in comatose patients was more common among patients who had regular visitors (P=.002), who had pre-coma pain (P=.006), who had nontreatment statements in their charts (P=.031), whose in-charge physician was an oncologist (P < .001), who were treated in a community nonprofit hospital compared with a Catholic hospital (P=.007), or who were treated in recent years (P=.011).

CONCLUSION

Both nontreatment and aggressive narcotic therapy forms of medical management have been occurring commonly in terminal pancreatic cancer patients in King County, Washington, during the past 3 decades, the latter with greater frequency in recent years.

In vivo pharmacokinetic screening in cassette dosing experiments; the use of on-line Pprospekt liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry technology in drug discovery

Drug discovery is a fast growing field and the number of compounds generated daily by the pharmecutical industry is enormous. The necessity of developing new experimental strategies and analytical methods to rapidly screen the pharmacokinetics (PK) behavior of these compounds becomes a real challenge. A novel strategy to support in vivo PK screening in cassette doing experiments, using a fully automated system capable of analyzing between 320 to 960 samples a day by instrument in n-in-one experiment ( n = 64 in this work), has been developed. Using an on-line extraction technique, the average observed recovery was 64% using a single C18 procedure. A weighted (1/x) linear equation was used to perform standard calibration (0.5 to 500 ng/microL) and the average R value obtained was 0.994 (R2 = 0.997) for 63 analytes. The limit of detection, defined as a signal-to-noise ratio of 3 or greater, was found to be 25 pg for 41 of the 63 analytes (65%) and 250 pg for 57 of the 63 analytes (90%). The complete automation procedure using the Prospekt-LC-APCI/MS/MS system has substantially improved throughput in the area of drug discovery and bioanalysis.

Mutagenic decomposition products of nitrosated 4-chloroindoles

4-Chloro-6-methoxyindole, a constituent of fava beans, forms a potent direct-acting mutagen, 4-chloro-6-methoxy-2-hydroxy-1-nitrosoindolin-3-one oxime, when nitrosated. In order to better understand the properties of this mutagen, we have studied a readily-available analog, 4-chloro-2-hydroxy-1-nitrosoindolin-3-one oxime, prepared by nitrosation of 4-chloroindole. This analog is also mutagenic, and both mutagens decompose rapidly at neutral or higher pH to yield in each case a new, less potent mutagen which then reacts further to form a nonmutagenic final product. The two products arising from 4-chloro-2-hydroxy-1-nitrosoindolin-3-one oxime, on the basis of comparison of spectroscopic and chromatographic evidence with that from authentic standards, are 4-chloro-N-nitrosodioxindole and 4-chloroisatin; those arising from 4-chloro-6-methoxy-2-hydroxy-1-nitrosoindolin-3-one oxime appear to be the corresponding 6-methoxy analogs. The interplay of these pathways with respect to net biological activity, especially under gastric conditions, remains to be described.

Serum proteolytic activity during the growth of C6 astrocytoma

Tumor growth is dependent on the ability of neoplastic cells to induce angiogenesis. Blood-vessel remodeling requires the reconstruction of the nonfibrous proteins and type IV collagen components of the basement membrane. This study has assessed the influence of the growth of C6 astrocytoma cells in the rat spheroid implantation model on serum general protease and type IV collagenase activity. The results demonstrate that general protease activity increased in serum, reaching maximum values on Day 6 and Day 13 following spheroid implantation, and that type IV collagenase activity increased in serum, obtaining maximum values on Day 8 and Day 15. The measurement of serum proteolytic activity may be of value in the detection of recurrent tumors.

Comparative in vitro metabolism of the cannabinoids

The metabolism of delta-9-tetrahydrocannabinol (delta-9-THC), delta-8-THC, delta-11-THC, cannabidiol (CBD), cannabinol (CBN), cannabichromene (CBC), cannabigerol (CBG) and the equatorial-isomer of hexahydrocannabinol (HHC) was studied in microsomal preparations obtained from rats, mice, guinea pigs, rabbits, hamsters, gerbils and a cat. Identification of metabolites was by GC/MS and quantification by gas chromatography. Major metabolites were monohydroxylated compounds but the pattern of hydroxylation varied considerably between the species, no doubt reflecting the variable nature of the cytochrome P-450 mixed-function oxidases. Although the primary carbon allylic to the endocyclic double bond of tricyclic cannabinoids was usually the major site of attack, the 4' (side-chain, omega-1 position) and the terpene ring were usually favoured by the cat and hamster respectively. The guinea pig generally produced more metabolites hydroxylated in the side-chain (all positions) than did the other species. The results from HHC were very similar to those from THC, namely hydroxylation at C-11 in most species, and the production of high concentrations of 8 alpha-hydroxy-HHC in the mouse and 8 beta-hydroxy-HHC in the hamster. As this molecule lacks the double bond of the THCs and, hence, the allylic nature of C-11 and C-8, the results suggest that it is the orientation of the molecule to the active site of the cytochrome P-450 mixed-function oxidase rather than the reactivity of the C-H bond that governs the position of hydroxylation.

Electron impact-induced fragmentation of the trimethylsilyl derivatives of monohydroxy-hexahydrocannabinols

Monohydroxylated derivatives of hexahydrocannabinols were synthesized by catalytic hydrogenation of hydroxytetrahydrocannabinols over a rhodium/alumina catalyst, reduction of tetrahydrocannabinol epoxides with lithium aluminium hydride, or by reaction of tetrahydrocannabinols with hydrogen peroxide. The electron impact-induced fragmentation of their trimethylsilyl ethers was investigated with the aid of deuterium labelling. Most of the compounds gave characteristically different mass spectra with abundant, diagnostically useful fragment ions. As hexahydrocannabinols containing hydroxy groups in all metabolically sensitive positions were readily prepared by the above methods, these provided reference samples for identification of new hydroxylated metabolites of isomeric tetrahydrocannabinols following hydrogenation. The method was validated by application to metabolites of delta-9(11)-tetrahydrocannabinol.

Identification of cannabichromene metabolites by mass spectrometry: identification of eight new dihydroxy metabolites in the rabbit

Metabolites of cannabichromene (CBC) produced by hepatic microsomal incubates from rabbits and mice were examined by gas chromatography/mass spectrometry (GC/MS) as trimethylsilyl (TMS) and (2H9)TMS derivatives. Most metabolites were hydroxylated compounds whose mass spectra gave very little information on metabolite structure as fragmentation was dominated by formation of the substituted chromenyl ion. This prevented charge localization and diagnostic fragmentation at the site of metabolic attack. This paper describes the identification of these metabolites by GC/MS techniques using both deuterium-exchange reactions and hydrogenation of the metabolites to tetrahydro derivatives; the latter method was used to suppress chromenyl ion formation and to enhance the relative abundance of diagnostic fragment ions. Twenty-one metabolites were identified. Metabolites were found hydroxylated in all positions of both aliphatic chains, with additional compounds formed by epoxidation and reduction of the aliphatic double bond in the methylpentenyl chain. Dihydroxy metabolites were hydoxylated in both the pentyl and methylpentenyl chains in positions common to those hydroxylated in the monohydroxy metabolites.

In vitro metabolism of cannabichromene in seven common laboratory animals

Metabolism of cannabichromene (CBC) was studied in hepatic microsomal incubates from mouse, rat, rabbit, guinea pig, cat, hamster, and gerbil. Metabolites were extracted with ethyl acetate, concentrated by chromatography on Sephadex LH-20, and identified by GC/MS as trimethylsilyl derivatives of both the metabolites themselves and their hydrogenated analogues. Thirteen metabolites were identified. The major metabolites were monohydroxy compounds with hydroxylation at all positions of the pentyl and methylpentenyl chains. An epoxide and its derived dihydrodiol were formed from the double bond in the methylpentenyl chains. Several unidentified decomposition products were found in the extracts from mouse, gerbil, and cat; these appeared to have been produced by the opening of the dihydropyran ring. Metabolism varied considerably between the species, although the trans-hydroxy metabolite 5'-hydroxy-CBC was the major metabolite in most cases. Metabolites hydroxylated in the pentyl chain were more abundant in mouse, rabbit, and cat; the hamster, gerbil, and cat produced the most epoxide-derived material.

In vitro metabolism of cannabigerol in several mammalian species

Microsomal incubations were prepared from the livers of male mice, rats, cats, guinea-pigs, hamsters and gerbils and both male and female rabbits and were incubated with cannabigerol (CBG), a constituent of marihuana. Metabolites were extracted with ethyl acetate, concentrated by chromatography on Sephadex LH-20 and examined as trimethylsilyl (TMS) and (2H9)TMS derivatives by gas chromatography/mass spectrometry. Structural elucidation was aided by hydrogenation of the metabolites to tetrahydro derivatives. Similar metabolites were produced by each of the species but the ratios of the individual compounds differed considerably. Twelve metabolites were identified. The major metabolites were monohydroxy compounds with the hydroxyl group at C-8', C-9', C-4' or at one of any position of the pentyl chain. Reduction of the delta-6' double bond was prominent in the cat to give 8'-hydroxy-6',7'-dihydro-CBG. The other major metabolic route was epoxidation of this double bond and hydrolysis to give 6',7'-dihydroxy-6',7'-dihydro-CBG. Although epoxidation of the other double bond was detected, the resulting metabolite was present in low concentration and hydrolysis was not observed. The mass spectral fragmentation of CBG and its metabolites was dominated by formation of the tropylium ion by cleavage of the C-1'--C-2' bond and by ions formed by cleavage of the C-3'--C-4' and C-4'--C-5' bonds. In addition, compounds containing hydroxylation at C-1"--C-4" (pentyl chain) gave rise to the same abundant diagnostic ions that have been observed for corresponding metabolites of other cannabinoids.

In vitro metabolism of cannabidiol in the rabbit: identification of seventeen new metabolites including thirteen dihydroxylated in the isopropenyl chain

The metabolism of cannabidiol (CBD) was studied in liver microsomes from the female New Zealand white rabbit. Metabolites were extracted with ethyl acetate, concentrated by chromatography on Sephadex LH-20 and examined as trimethylsilyl (TMS), methyl ester/TMS and (2H9)TMS derivatives by gas chromatography/mass spectrometry. Thirty-nine metabolites, mainly mono-, di- and tri-hydroxy compounds, were identified; 17 of these have not been reported before. New metabolites included 8,9-dihydroxy-8,9-dihydro-CBD (two isomers) and seven monohydroxy derivatives of each of these two compounds. The mass spectra of the TMS derivatives of metabolites not hydroxylated in the isopropenyl group were generally dominated by the ion produced by retro-Diels-Alder cleavage of the terpene ring. Other structurally informative ions included the tropylium ion and fragments diagnostic of hydroxylation at C-1", C-2", C-3", C-4" and C-7. The spectra of the TMS derivatives of metabolites hydroxylated in the isopropenyl group were generally dominated by the ion at m/z 143. This involved loss of CH2OTMS and a retro-Diels-Alder fragmentation analogous to that seen in the other metabolites, but with charge retention by the other (smaller) fragment. Other, related fragment ions also characterized these metabolites.

In vitro metabolism of cannabinol in rat, mouse, rabbit, guinea pig, hamster, gerbil and cat

Metabolism of cannabinol (CBN) was studied in hepatic microsomal incubates from mouse, rat, rabbit, guinea pig, cat, hamster and gerbil. Metabolites were extracted with ethyl acetate, concentrated by chromatography on Sephadex LH-20 and identified by GC/MS as TMS derivatives. Six monohydroxy metabolites were identified. These had hydroxy groups at C-11 and at all positions of the pentyl side-chain. Metabolism varied considerably between the species. 11-Hydroxylation was the most prominent route in the majority of species, but in the hamster and cat the major metabolic pathway was 4'-hydroxylation. Metabolites hydroxylated in the pentyl chain were generally more abundant in guinea pig, hamster and cat.

In vitro metabolism of delta-11-tetrahydrocannabinol in the mouse, rat, guinea pig, rabbit, hamster, gerbil and cat

1. Liver microsomes were prepared from rats, rabbits, guinea pigs, hamsters, gerbils, a cat and three strains of mice, and were incubated with delta-11-tetrahydrocannabinol (delta-11-THC). The extracted metabolites were separated by chromatography on Sephadex LH-20 and examined by gas chromatography and combined gas chromatography/mass spectrometry. 2. Eleven metabolites were identified; these were formed by aliphatic hydroxylation of all positions of the pentyl chain, allylic hydroxylation at C-10 and C-8 (alpha and beta), and by the epoxide-diol pathway. 3. The ratio of the metabolites varied considerably between the species. Mice and rats favoured hydroxylation at C-8-alpha with very little hydroxylation of the pentyl chain. 4. In the guinea pig, however, hydroxylation of the pentyl chain, particularly at C-4', produced the major metabolites; very little hydroxylation occurred at C-8. 5. Side-chain hydroxylation was also favoured by the gerbil. 6. In the cat and hamster, 8-beta-hydroxylation was by far the major metabolic route, accounting, in the cat, for nearly 70% of the recovered metabolites. 7. The rabbit, on the other hand, favoured the epoxide-diol pathway with over 70% of the recovered metabolites being accounted for by the 9,11-dihydro-diols. 8. The results emphasise the need to make appropriate choices of animal models for metabolic and toxicological studies in humans.

Metabolism of n-hexyl-homologues of delta-8-tetrahydrocannabinol and delta-9-tetrahydrocannabinol in the mouse

n-Hexyl-delta-8-tetrahydrocannabinol (n-hexyl-delta-8-THC) and n-hexyl-delta-9-THC were synthesized by condensation of (1S)-cis-verbenol with 5-n-hexyl-1,3-dihydroxybenzene and administered intraperitoneally to male Charles-River CD-1 mice. Hepatic metabolites were isolated by solvent extraction and chromatography on Sephadex LH-20 and identified by GC/MS. Eleven metabolites were identified from n-hexyl-delta-8-THC and sixteen from n-hexyl-delta-9-THC. The pattern of metabolites was intermediate between that previously observed from the pentyl homologues and that from n-heptyl-delta-9-THC with the major biotransformation pathway being hydroxylation and oxidation at C-11. Other metabolites were mainly hydroxylated derivatives of these compounds. Metabolites containing two hydroxy groups in the side-chain were present in low concentration. These have not been observed from lower homologues but are major metabolites of n-heptyl-delta-9-THC. Compared with the metabolism of the n-pentyl homologue, there was a trend towards the production of more hydroxy metabolites at the expense of carboxylic acids, in keeping with the general reduction of oxidation observed with other homologous cannabinoids as the chain length increases.

In vivo metabolism of the methyl homologues of delta-8-tetrahydrocannabinol, delta-9-tetrahydrocannabinol and abn-delta-8-tetrahydrocannabinol in the mouse

Methyl-delta-8-tetrahydrocannabinol (methyl-delta-8-THC), methyl-delta-9-THC and abn-methyl-delta-8-THC were synthesized by condensation of orcinol and (1S)-cis-verbenol and were administered to male Charles River CD-1 mice. Extracted hepatic metabolites were isolated by chromatography on Sephadex LH-20 and examined by gas chromatography/mass spectrometry as trimethylsilyl (TMS), (2H9)TMS and methyl ester/TMS derivatives. In addition, metabolic fractions were reduced with lithium aluminium deuteride to convert carboxylic acids to alcohols for structural correlation. Metabolites from methyl-delta-8-THC were similar with respect to the positions substituted to those produced by higher homologues; the major metabolite was methyl-delta-8-THC-11-oic acid. abn-Methyl-delta-8-THC was metabolized in a different manner. The location of the aromatic methyl group at the position adjacent to ring fusion appeared to inhibit metabolism at C(11) to a considerable extent and also to reduce the amount of the resulting alcohol from being oxidized to a carboxylic acid. This caused other metabolic pathways to become dominant, with the result that a compound containing a hydroxy group at the gem-methyl position was the major metabolite. Hydroxylation at this position has not been confirmed with any other cannabinoid, although it is thought to result in trace concentrations of hydroxy metabolites from some compounds. Metabolism of methyl-delta-9-THC was also similar to that of the higher homologues, with the exception that less metabolism occurred at C(8) and a higher percentage of the total metabolic fraction was accounted for by the 11-oic acid metabolite. Minor metabolites were mainly dihydroxy compounds and hydroxylated derivatives of delta-9-THC-11-oic acid.

In vivo metabolism of the n-butyl-homologues of delta 9-tetrahydrocannabinol and delta 8-tetrahydrocannabinol by the mouse

1. n-Butyl-homologues of delta 8-tetrahydrocannabinol (delta 8-THC) and delta 9-THC were synthesized from 5-butyl-1,3-dihydroxybenzene and (1S)-cis-verbenol, and the delta 9-isomer was shown to have the same g.l.c.-mass spectral characteristics as the natural product. 2. Metabolism of these cannabinoids was studied in mice following i.p. injection. Metabolites were extracted from the livers, separated from endogenous lipids by chromatography on Sephadex LH-20 and examined by g.l.c.-mass spectrometry. 3. Thirteen metabolites were identified from both n-butyl-delta 8-THC and n-butyl-delta 9-THC. 4. Major metabolic routes were hydroxylations in the 2', 3', 8 and 11 positions and oxidation of the resulting 11-hydroxy-metabolites to carboxylic acids. 5. Metabolism was very similar to that of the pentyl homologues, the major constituents of cannabis, but with the production of a greater proportion of acidic metabolites at the expense of alcohols.

In vivo metabolism of the n-propyl homologues of delta-8- and delta-9-tetrahydrocannabinol in the mouse

n-Propyl-delta-8-tetrahydrocannabinol (n-propyl-delta-8-THC and n-propyl-delta-9-THC were synthesized by condensation of (1S)-cis-verbenol with 5-n-propyl-1,3-dihydroxybenzene and administered to male Charles River CD-1 mice. Hepatic metabolites were isolated by solvent extraction and chromatography on Sephadex LH-20 and identified by gas chromatography/mass spectrometry. Seven metabolites were identified from each cannabinoid. Metabolism was similar to that previously observed from the penyl homologues, with the major biotransformation pathway being the production of 11-hydroxy-propyl-THCs and their oxidation to carboxylic acid metabolites. Other metabolites were mainly hydroxylated derivatives of these compounds and the corresponding 11-alcohol. Less hydroxylation at C(8) was found with n-propyl-delta-9-THC than with the pentyl homologue, and the monohydroxy metabolite, 8-alpha-hydroxy-n-propyl-delta-9-THC, was not observed, even though it was a prominent metabolite from delta-9-THC itself. Hydroxylation occurred in the side-chain at C(2').

Factors affecting place of death in Washington State, 1968-1981

A study was carried out to determine factors affecting place of death (home, hospital, nursing home or "other places") among all 426,115 resident deaths in Washington State during 1968-1981, using death certificate information. Sixteen percent of deaths occurred at home, 74% in institutions (51% in hospitals, 23% in nursing homes) and 9% at "other places." Age, marital status and cause of death all strongly affect place of death. Further, the effect of each factor was strongly dependent on the others. Sex had no effect on place of death after controlling for other factors. Elderly people died relatively more frequently in nursing homes, infants and middle aged people in hospitals and young adults in "other places." The frequency of deaths at home was quite constant by age. Hospitals were the most common place of death following both vascular disease (including heart attack) and neoplasms, and nursing homes were the most common place of death following cerebrovascular disease (including "stroke"). Race, socioeconomic status and urban or rural residents affected the place of death only slightly or not at all. The place of death pattern changed little during the time period 1968-1981, except for a slight increase in frequency of home deaths and a corresponding decrease in the frequency of deaths in other places. Among cancer patients, the likelihood of death at home was positively associated with longer periods of survival after diagnosis. Cancer patients of hospitals serving targeted populations, such as veterans, were relatively more likely to die in a hospital and less likely to die in a nursing home compared to other cancer patients, suggesting that the "targeted" hospitals are sometimes serving a nursing home function. There was a marked difference in the terminal cancer caseload by hospital. The number of cancer deaths per cancer diagnosis varied widely across hospitals (0.1 to 1.6) and was unrelated to size of the hospital or level of services offered. Intervention aimed at affecting place of death, such as increasing the number of deaths at home, will need to take account of the joint effect of age, marital status and disease.

Nontreatment of fever in extended-care facilities

In a study of decisions not to treat febrile patients, we reviewed the medical records of 1256 people admitted to nine extended-care facilities in Seattle during 1973. Fever, defined as two temperatures of 38.33 degrees C to 38.83 degrees C (101 to 101.9 degrees F), within 24 hours or one temperature greater than or equal to 38.88 degrees C (102 degrees F), developed in 190 patients before two years of stay. Active treatment, defined as antibiotics or hospitalization (or both), was ordered for fever in 109 patients, of whom 10 (9 per cent) died. Active treatment was not ordered for 81 patients, of whom 48 (59 per cent) died. The pre-decision factors that showed a significant relation (P less than 0.05) to such nontreatment were: diagnosis, mental status, mobility, pain, narcotics prescribed, size of the facility, relation of the physician to the patient and medical-record statements documenting the patient's deterioration or plans for nontreatment in general. This pattern of nontreatment suggests that physicians and nurses did not intend to treat these patients actively and that high mortality was expected.

Evaluation of an indanyl ester of carbenicillin

Cultures of tetracycline-treated Staphylococcus aureus exhibited monophasic steady-state growth curves similar to that observed for tetracycline-treated Escherichia coli. Apparent growth rate constants of the respective drug-treated cultures showed the same formal dependence on drug concentration, which was linear at a low concentration but asymptotically approached zero at higher concentration levels and implied the saturation of a limited number of receptor sites engaged in microbial protein synthesis. The relative potency of tetracycline action of S. aureus/E. coli was 6.50:1 at 37.5°C and pH 7.05. This is attributed to relative differences in drug permeation and/or binding affinity for biophase receptors in the respective organisms. It is concluded from kinetic dependencies of growth inhibition of the cultures that tetracycline has the same mode of action on S. aureus and E. coli. It is bacteriostatic at concentrations below the minimal inhibitory concentration level but bactericidal at the higher concentration levels.

Selective Viral and Rickettsial Serum Antibody Absorption by a Chromatographic Column

Serum antibodies behave as cations at neutral pH and thus have low affinity for cellulose anion-exchange columns. Antigens of small size derived from adenovirus, influenza virus, and typhus rickettsiae, however, readily adsorbed to such columns. These adsorbed antigens specifically removed antibodies from antisera. This simple method permits antibody absorption by antigens ordinarily sedimented with difficulty.