AN OUTBREAK OF FELINE INFECTIOUS PERITONITIS IN THREE RELATED SAND CATS (FELIS MARGARITA) IN HUMAN CARE

Feline infectious peritonitis (FIP) is a systemic disease in felid species caused by infection with mutated forms of feline coronavirus (FCoV), and outbreaks can devastate exotic felid populations in human care. Feline infectious peritonitis was diagnosed in three of four related juvenile sand cats (Felis margarita) from a single institution over a 6-wk period. Case 1 was a 7-mon-old male found deceased with no premonitory signs. Case 2, an 8-mon-old male (littermate to Case 1), and Case 3, a 6-mon-old male (from a different litter with identical parentage), were evaluated for lethargy and anorexia 1 mon after Case 1. Both exhibited transient anisocoria and progressive lethargy, anorexia, and dehydration despite antibiotic and supportive treatment. Approximately 1 wk after initial presentation, Case 2 was humanely euthanized, and Case 3 was found deceased. Necropsy findings included intrathoracic and/or intra-abdominal lymphadenopathy (3/3 cases), bicavitary effusion (2/3), multifocal tan hepatic and intestinal nodules (1/3), and multifocal yellow renal nodules (1/3). Histologically, all cats had severe pyogranulomatous vasculitis in multiple organs, and the presence of FCoV antigen was confirmed using immunohistochemical staining. Next-generation sequencing of the virus from Case 3's affected kidney demonstrated ∼93% homology to the UG-FH8 virus, a serotype 1 feline alphacoronavirus isolated from Denmark. Future research will focus on comparative viral genomic sequencing with the goals of identifying potential sources of FCoV infection and identifying features that may have contributed to the development of FIP in this species.

A 2-Year Longitudinal Study of Bone Mineral Density in Collegiate Distance Runners

ABSTRACT

Brimacomb, OE, Martinez, MP, McCormack, WP, and Almstedt, HC. A 2-year longitudinal study of bone mineral density in collegiate distance runners. J Strength Cond Res XX(X): 000-000, 2022-The purpose of this investigation was to examine changes in bone mineral density (BMD) of male and female collegiate distance runners over 2 years. Bone mineral density of 29 collegiate distance runners (16 men and 13 women) were measured 5 times over 24 months using dual-energy x-ray absorptiometry (DXA) at the anterior-posterior (AP) and lateral (LAT) spine, femoral neck (FN), total hip (TH), whole body (WB), and ultradistal (UD) forearm. Repeated-measures multivariate analysis of covariance, with bone-free lean mass (BFLM) as covariate, was used to compare mean BMD values. Adjusted for BFLM, there were no significant differences (p > 0.05) in BMD at any site between sexes. There were no significant differences at the AP or LAT spine, FN, or WB between visit 1 and 5 for either sex. There was a significant increase in BMD (p = 0.044) at the UD forearm over 2 years in males. However, 56% of the men (n = 9) had a Z-score < -1.0 at the UD forearm. Seven of 11 women had Z-scores < -1.0 at the LAT spine and 4 of 13 had Z-scores < -1.0 at the AP spine. There were no significant changes in BMD at any site over the 2-year time frame, except a significant increase in BMD at the nondominant forearm in men. The spine appears to be an area of concern for women in this study when examining Z-score results. Coaches and medical staff need to continually educate collegiate endurance athletes about the importance of achieving and maintaining BMD through their college years.

Epigenomic regulation of human T-cell leukemia virus by chromatin-insulator CTCF

Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that causes an aggressive T-cell malignancy and a variety of inflammatory conditions. The integrated provirus includes a single binding site for the epigenomic insulator, CCCTC-binding protein (CTCF), but its function remains unclear. In the current study, a mutant virus was examined that eliminates the CTCF-binding site. The mutation did not disrupt the kinetics and levels of virus gene expression, or establishment of or reactivation from latency. However, the mutation disrupted the epigenetic barrier function, resulting in enhanced DNA CpG methylation downstream of the CTCF binding site on both strands of the integrated provirus and H3K4Me3, H3K36Me3, and H3K27Me3 chromatin modifications both up- and downstream of the site. A majority of clonal cell lines infected with wild type HTLV-1 exhibited increased plus strand gene expression with CTCF knockdown, while expression in mutant HTLV-1 clonal lines was unaffected. These findings indicate that CTCF binding regulates HTLV-1 gene expression, DNA and histone methylation in an integration site dependent fashion.

Human T-cell leukemia virus type 1 (HTLV-1) is a cause of leukemia and lymphoma as well as several inflammatory medical disorders. The virus integrates in the host cell DNA, and it has a single binding site for a protein designated CTCF. This protein is important in the regulation of many DNA viruses, as well as many properties of normal and malignant cells. In order to define the role of CTCF binding to HTLV, we analyzed a mutant virus lacking the binding site. We found that this mutation variably affected gene expression, DNA and histone modification, suggesting a key role in regulation of virus replication in infected cells.

HTLV-1 CTCF-binding site is dispensable for in vitro immortalization and persistent infection in vivo

BACKGROUND

Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia/lymphoma (ATL) and the neurological disorder HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The exact mechanism(s) through which latency and disease progression are regulated are not fully understood. CCCTC-binding factor (CTCF) is an 11-zinc finger, sequence-specific, DNA-binding protein with thousands of binding sites throughout mammalian genomes. CTCF has been shown to play a role in organization of higher-order chromatin structure, gene expression, genomic imprinting, and serve as a barrier to epigenetic modification. A viral CTCF-binding site (vCTCF-BS) was previously identified within the overlapping p12 (sense) and Hbz (antisense) genes of the HTLV-1 genome. Thus, upon integration, HTLV-1 randomly inserts a vCTCF-BS into the host genome. vCTCF-BS studies to date have focused primarily on HTLV-1 chronically infected or tumor-derived cell lines. In these studies, HTLV-1 was shown to alter the structure and transcription of the surrounding host chromatin through the newly inserted vCTCF-BS. However, the effects of CTCF binding in the early stages of HTLV-1 infection remains unexplored. This study examines the effects of the vCTCF-BS on HTLV-1-induced in vitro immortalization and in vivo viral persistence in infected rabbits.

RESULTS

HTLV-1 and HTLV-1∆CTCF LTR-transactivation, viral particle production, and immortalization capacity were comparable in vitro. The total lymphocyte count, proviral load, and Hbz gene expression were not significantly different between HTLV-1 and HTLV-1∆CTCF-infected rabbits throughout a 12 week study. However, HTLV-1∆CTCF-infected rabbits displayed a significantly decreased HTLV-1-specific antibody response compared to HTLV-1-infected rabbits.

CONCLUSIONS

Mutation of the HTLV-1 vCTCF-BS does not significantly alter T-lymphocyte transformation capacity or early in vivo virus persistence, but results in a decreased HTLV-1-specific antibody response during early infection in rabbits. Ultimately, understanding epigenetic regulation of HTLV-1 gene expression and pathogenesis could provide meaningful insights into mechanisms of immune evasion and novel therapeutic targets.

Radiation-induced sarcoma in a cat following hypofractionated, palliative intent radiation therapy for large-cell lymphoma

Case summary

A 5-year-old female spayed domestic shorthair cat was presented with a 4.5 × 3 cm ulcerated cutaneous mass on the nasal bridge with extension into the nasal cavity. Tissue biopsy was obtained and a diagnosis of large-cell lymphoma was confirmed on histopathology. The cat was started on prednisolone and injectable chemotherapy; however, only a partial response was observed. A CT scan revealed a highly infiltrative mass with extensive subcutaneous involvement, extending into the nasal cavity, resulting in lysis of numerous nasal and facial bones. The cat received hypofractionated, palliative intent radiation therapy (four fractions of 8 Gray) and a complete clinical response was achieved. Nine months after radiation therapy, minimal residual intranasal disease was observed on advanced imaging. Sixty-nine months after the completion of radiotherapy, a mass was observed dorsal to the right eye within the previous radiation field. CT scan revealed a mass associated with the right frontal sinus with extension throughout the nasal cavity and facial bones. Histopathology was consistent with a moderately differentiated sarcoma. Seventy-one months post-radiation therapy, the cat developed neurologic clinical signs and was humanely euthanized. Radiation-induced sarcoma was suspected based on human criteria, which included history of irradiation and tumor development within the irradiated field, a latent period after irradiation prior to the development of the second tumor and histopathologic confirmation of a different malignant neoplasm at the irradiated site.

Relevance and novel information

To our knowledge, this is the first report of a malignant radiation-induced sarcoma in a cat. Based on this case, radiation-induced sarcomas should be considered as a late-term side effect associated with radiation therapy in cats.

Comparative virology of HTLV-1 and HTLV-2

Human T cell leukemia virus type 1 (HTLV-1) was the first discovered human retrovirus and the etiologic agent of adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. Shortly after the discovery of HTLV-1, human T-cell leukemia virus type 2 (HTLV-2) was isolated from a patient with hairy cell leukemia. Despite possession of similar structural features to HTLV-1, HTLV-2 has not been definitively associated with lymphoproliferative disease. Since their discovery, studies have been performed with the goal of highlighting the differences between HTLV-1 and HTLV-2. A better understanding of these differences will shed light on the specific pathogenic mechanisms of HTLV-1 and lead to novel therapeutic targets. This review will compare and contrast the two oldest human retroviruses with regards to epidemiology, genomic structure, gene products, and pathobiology.

HTLV-1 Tax-1 interacts with SNX27 to regulate cellular localization of the HTLV-1 receptor molecule, GLUT1

An estimated 10-20 million people worldwide are infected with human T cell leukemia virus type 1 (HTLV-1), with endemic areas of infection in Japan, Australia, the Caribbean, and Africa. HTLV-1 is the causative agent of adult T cell leukemia (ATL) and HTLV-1 associated myopathy/tropic spastic paraparesis (HAM/TSP). HTLV-1 expresses several regulatory and accessory genes that function at different stages of the virus life cycle. The regulatory gene Tax-1 is required for efficient virus replication, as it drives transcription of viral gene products, and has also been demonstrated to play a key role in the pathogenesis of the virus. Several studies have identified a PDZ binding motif (PBM) at the carboxyl terminus of Tax-1 and demonstrated the importance of this domain for HTLV-1 induced cellular transformation. Using a mass spectrometry-based proteomics approach we identified sorting nexin 27 (SNX27) as a novel interacting partner of Tax-1. Further, we demonstrated that their interaction is mediated by the Tax-1 PBM and SNX27 PDZ domains. SNX27 has been shown to promote the plasma membrane localization of glucose transport 1 (GLUT1), one of the receptor molecules of the HTLV-1 virus, and the receptor molecule required for HTLV-1 fusion and entry. We postulated that Tax-1 alters GLUT1 localization via its interaction with SNX27. We demonstrate that over expression of Tax-1 in cells causes a reduction of GLUT1 on the plasma membrane. Furthermore, we show that knockdown of SNX27 results in increased virion release and decreased HTLV-1 infectivity. Collectively, we demonstrate the first known mechanism by which HTLV-1 regulates a receptor molecule post-infection.

Maternal obesity, gestational diabetes, breastfeeding and childhood overweight at age 2 years

BACKGROUND

Maternal obesity, excessive gestational weight gain (EGWG), gestational diabetes mellitus (GDM) and breastfeeding are four important factors associated with childhood obesity.

OBJECTIVES

The objective of the study was to assess the interplay among these four factors and their independent contributions to childhood overweight in a cohort with standard clinical care.

METHODS

The cohort included 15 710 mother-offspring pairs delivered in 2011. Logistic regression was used to assess associations between maternal exposures and childhood overweight (body mass index >85th percentile) at age 2 years.

RESULTS

Mothers with pre-pregnancy obesity or overweight were more likely to have EGWG, GDM and less likely to breastfeed ≥6 months. Mothers with GDM had 40-49% lower EGWG rates and similar breastfeeding rates compared with mothers without GDM. Analysis adjusted for exposures and covariates revealed an adjusted odds ratio (95% confidence interval) associated with childhood overweight at age 2 years of 2.34 (2.09-2.62), 1.50 (1.34-1.68), 1.23 (1.12-1.35), 0.95 (0.83-1.10) and 0.76 (0.69-0.83) for maternal obesity, overweight, EGWG, GDM and breastfeeding ≥6 months vs. <6 months, respectively.

CONCLUSIONS

In this large clinical cohort, GDM was not associated with, but maternal pre-pregnancy obesity or overweight and EGWG were independently associated with an increased risk, and breastfeeding ≥6 months was associated with a decreased risk of childhood overweight at age 2 years.

Inhibition of polyamine synthesis arrests trichomonad growth and induces destruction of hydrogenosomes

Trichomonad parasites such as Tritrichomonas foetus produce large amounts of putrescine (1,4-diaminobutane), which is transported out of the cell via an antiport mechanism which results in the uptake of a molecule of spermine. The importance of putrescine to the survival of the parasite and its role in the biology of T. foetus was investigated by use of the putrescine analogue 1, 4-diamino-2-butanone (DAB). Growth of T. foetus in vitro was significantly inhibited by 20 mM DAB, which was reversed by the addition of exogenous 40 mM putrescine. High-performance liquid chromatography analysis of 20 mM DAB-treated T. foetus revealed that putrescine, spermidine, and spermine levels were reduced by 89, 52, and 43%, respectively, compared to those in control cells. The DAB treatment induced several ultrastructural alterations, which were primarily observed in the redox organelles termed hydrogenosomes. These organelles were progressively degraded, giving rise to large vesicles that displayed material immunoreactive with an antibody to beta-succinyl-coenzyme A synthetase, a hydrogenosomal enzyme. A protective role for polyamines as stabilizing agents in the trichomonad hydrogenosomal membrane is proposed.

Reconstitution of a bacterial/plant polyamine biosynthesis pathway in Saccharomyces cerevisiae

Polyamine synthesis in most organisms is initiated by the decarboxylation of ornithine to form putrescine via ornithine decarboxylase (ODC). Plants, some bacteria and some fungi and protozoa generate putrescine from arginine, via arginine decarboxylase (ADC) and agmatine ureohydrolase (AUH) or agmatine iminohydrolase. A polyamine-requiring strain of Saccharomyces cerevisiae with a mutation in the gene encoding ODC was transformed with plasmids bearing genes encoding Escherichia coli ADC and AUH. Transformants regained the ability to grow in the absence of exogenous polyamines and contained enzyme activities consistent with the presence of both prokaryotic enzymes. Similar results were obtained when a plasmid containing a gene encoding oat (Avena sativa L.) ADC was substituted for the E. coli gene. These data demonstrate the successful complementation of a yeast biosynthetic polyamine synthesis defect by genes encoding an alternative pathway found in bacteria; they also show that plant ADC can substitute for the bacterial enzyme in this pathway. The recombinant yeast provides a tool for the study of the functional properties of these enzymes and for discovery of compounds that specifically inhibit this pathway.

Prevalence of micro- and macroalbuminuria in a Canarian population of type 2 diabetic patients. Relationship with blood pressure, lipid profile, obesity and metabolic control

We performed a cross-sectional study on the prevalence of micro- and macroalbuminuria in a population of 288 Type 2 diabetic patients from Northern Gran Canaria Island (age 59 +/- 9.5, years; 48% male): 179 unselected patients referred by their family physicians, and 109 from our diabetes clinic. Sex, age, duration of diabetes and hypertension, blood pressure, body mass index, waist-hip ratio, HbA1c, creatinine, cholesterol (total and HDL), triglycerides, lipoprotein (a), and the presence of retinopathy, polyneuropathy, and coronary and cerebrovascular disease were assessed. The prevalences of micro- and macroalbuminuria were 28.5% and 11.8%. Among the patients referred by their family physicians, 32.4% were micro- and 6.1% macroalbuminuric. In our diabetes clinic, there were respectively 22% and 21% (with a higher prevalence of macroalbuminuria than in primary care, p < 0.05). Seventy-three percent were hypertensive in both settings. Prevalence was 31.5% for diabetic retinopathy, 21.0% for diabetic polyneuropathy, 8.1% for cerebrovascular disease, and 20.2% for coronary heart disease. The albumin excretion rate was significantly correlated with plasma creatinine levels, diastolic blood pressure, total cholesterol and the presence of coronary heart disease and diabetic retinopathy, but not with age, duration of diabetes or hypertension, body mass index, waist/hip ratio, glycated haemoglobin or triglycerides.

Polyamine biosynthesis in Cryptosporidium parvum and its implications for chemotherapy

This study demonstrates that polyamine biosynthesis in Cryptosporidium parvum occurs via a pathway chiefly found in plants and some bacteria. The lead enzyme of this pathway, arginine decarboxylase (ADC) was sensitive to the specific, irreversible inhibitor DL-alpha-difluoromethyl-arginine (IC50 30 microM), and intracellular growth of C. parvum was significantly reduced by inhibitors of ADC. No activity was detected using ornithine as substrate, and the irreversible inhibitor of ornithine decarboxylase, DL-alpha-difluoromethyl-ornithine, had no effect upon ADC activity or upon growth of the parasite. Back-conversion of spermine to spermidine and putrescine via spermidine:spermine-N1-acetyltransferase (SSAT) was also detected. Compounds such as his(ethyl)norspermine, which have been demonstrated to down-regulate SSAT activity in tumor cells, were synergistic in the inhibition of growth when used in combination with inhibitors of the forward pathway. Thus, C. parvum differs fundamentally in its polyamine metabolism from the majority of eukaryotes, including humans. Such differences indicate that polyamine metabolism may serve as a chemotherapeutic target in this organism.

The contribution of the arginine dihydrolase pathway to energy metabolism by Trichomonas vaginalis

The enzymes of the arginine dihydrolase pathway were measured in Trichomonas vaginalis hydrogenosome-deficient lines MR-5 and MR-100, and the parent strain TV 10-02. The activities and substrate affinities of arginine deiminase, carbamate kinase and ornithine decarboxylase were similar for the hydrogenosome-deficient lines and the parent TV 10-02. The activity of catabolic ornithine carbamyltransferase, however, was found to be 5-7-fold elevated in the hydrogenosome-deficient lines; the apparent K(m) for citrulline was similar for all of the lines. Putrescine biosynthesis by the hydrogenosome-deficient cell lines was found to be significantly higher than the parent. Incubation of strain MR-100 with U-[14C]-arginine resulted in a 5-fold greater amount of 14CO2 liberated compared to the parent strain TV 10-02. Inclusion of the ornithine decarboxylase inhibitor difluoromethylornithine in these incubations reduced the CO2 production of strain TV 10-02 by 42%, but only inhibited the MR-100 strain by 14.5%, indicative that the majority of the CO2 liberated from arginine by this strain is derived from the elevated activity of ornithine carbamyltransferase. Despite the increased flow through the arginine dihydrolase pathway, the energy gain to the parasite is approximately 10% of that from glucose, thus, under the growth conditions used in this study carbohydrate metabolism provides the bulk of the ATP for the parasite.

Higher erythropoietin secretion in response to cobaltous chloride in post-hypoxic than in hypertransfused polycythemic mice

BACKGROUND

We have shown previously that both erythrocyte production rate (EPR) and plasma erythropoietin (EPO) levels in response to hypoxia or to compounds able to stimulate EPO secretion are very much higher in post-hypoxic (PH) than in hypertransfused (HT) polycythemic mice with similar levels of hematocrit. Since it has been demonstrated that cobalt (Co) treatment rises renal EPO-mRNA and increases plasma EPO levels, the present study was conducted to determine whether there is a difference between PH and HT mice in relation to the erythropoietic response to Co and whether the stimulatory effect of Co on EPO secretion can be blunted by polycythemia.

METHODS

Adult female mice of the CF-1 strain were made polycythemic by either exposing them to 270 h of discontinuous hypoxia (18 h/d) in a hypobaric chamber maintained at 456 hPA (PH mice) or by injecting them with 0.8 ml of washed packed red cells on two consecutive days (HT mice). Measurement of the erythrocyte production rate (EPR) was made by RBC-59Fe uptake. Plasma EPO concentration was determined by RIA. Cobalt chloride (CoC12) was dissolved in saline and injected in doses of 4 and 8 umoles/mouse. Recombinant human EPO (HEMAX 4000, Bio Sidus SA, Argentina) was dissolved in PBS + albumin to the desired concentration.

RESULTS

By comparison with the corresponding dose-regression line for rHu-EPO, it was estimated that the responses (EPR) (measured as RBC-59Fe incorporation) of PH mice to sc injections of 4 and 8 umoles of CoC12 were equivalent to 95 and 145 mU of rHu-EPO, respectively. The response of HT mice to 4 umoles of the drug was not detectable. At the upper dose level, the response was equivalent to 52 mU of rHuEPO. Plasma immunoreactive EPO (iEPO) titers 12 h after COC12 (8 umoles) were not significantly different between normocythemic and PH mice. The observed values were significantly higher than those found in HT mice.

DISCUSSION

These findings demonstrate that EPO production in response to COC12 is depressed by polycythemia when induced by transfusion but not when induced by chronic exposure to hypobaric hypoxia. They also confirm, but not explain the nature of the conditioning effect of exposure to hypoxia which makes the mechanism controlling EPO secretion either more sensitive to EPO-secreting stimuli or unable to recognize the polycythemic state.

Congenital adrenal hypoplasia in a male with gonadotropin deficiency

We report the case of a boy with adrenal insufficiency diagnosed at the age of 2.5 months. He required immediate therapy with corticosteroids. His two brothers and a cousin died in infancy with vomiting and dehydration. Aged 17.5 years (bone age 13 years), he showed no signs of puberty, a testicular volume of 2 ml, an infantile penis, and no axillary or pubic hair. There was no evidence of a pubertal growth spurt. The low plasma levels of cortisol, 17-OHP, delta-4-A, LH and FSH did not increase after stimulation with ACTH or LHRH respectively. Urinary testosterone levels before and after HCG were extremely low. These factors strongly suggest the diagnosis of a sex-linked type of adrenal insufficiency (cytomegalic form), associated with gonadotropin deficiency.