Use of remdesivir for COVID-19 pneumonia in patients with advanced kidney disease: A retrospective multicenter study.

Background and objectives: Remdesivir, an antiviral drug routinely used in the treatment of COVID-19 has not yet received FDA approval for use in patients with advanced kidney disease defined as GFR < 30 mL/min/1.73 m2. There is concern that an excipient in Veklury (Gilead's proprietary name for remdesivir) called sulfobutylether-beta-cyclodextrin (SBECD), which is renally cleared, may accumulate and reach toxic levels in patients with advanced kidney disease. The aim of this study was to summarize characteristics and incidence of adverse events of chronic kidney disease (CKD) patients who received remdesivir during hospitalization.Design, setting, participants, and measurements.We retrospectively studied patients admitted to one of several hospitals of the Mayo Clinic Foundation with the diagnosis of COVID-19 pneumonia and CKD. Laboratory values were also measured when remdesivir was first administered and stopped. All analyses were performed in the overall patient group and three separate subgroups of patients with a GFR ≥ 15, a GFR < 15 and dialysis, and a GFR < 15 and no dialysis. Results: A total of 444 CKD patients who were admitted to the hospital with COVID-19 pneumonia between May 2020 and September 2021 were included. Information was collected on patient characteristics, hospitalization, and adverse events. In the overall cohort, median age was 72 years (Range: 21-100 years), 55.2 % of patients were male, and most (86.5 %) were Caucasian. CKD stage was 3 for 114 patients (25.7 %), 4 for 229 patients (51.6 %), and 5 for 101 patients (22.7 %). A total of 146 patients (32.9 %) were admitted to the ICU, 103 (23.2 %) died in the hospital, and 120 (27.0 %) were on dialysis. The proportion of patients with an adverse event did not differ dramatically between the GFR ≥ 15 (20.9 %), GFR < 15 and dialysis (30.2 %), and GFR < 15 and no dialysis (32.3 %) groups (P = 0.12). Conclusion: Our results suggest that the use of remdesivir in patients with very severe CKD is safe, even in those who are not on renal replacement therapy.

Salicylic acid inhibits ultraviolet- and cis-platinum-induced human immunodeficiency virus expression.

Previous studies have shown that exposure of HeLa cells stably transfected with an HIV-long terminal repeat-chloramphenicol acetyltransferase (HIV-LTR-CAT) construct to many DNA-damaging agents (such as UV light) induces expression from the HIV LTR. By culturing the cells with salicylic acid we demonstrated dose-dependent repression of this UV-or cis-platinum (cis-Pt)-induced HIV expression. While salicylic acid treatment, indomethacin treatment, UV exposure, or cis-Pt treatment alone decreased viability by up to 50%, equal numbers of viable cells were used for the CAT assays. Repression was evident if salicylic acid was administered 2 h before, at the same time as, or up to 6 h after exposure to the DNA-damaging agent. The kinetics were similar for UV- and for cis-Pt-induced HIV expression, and induction was dependent on the UV dose or cis-Pt concentration added to the culture. pH changes of the media alone in the absence of salicylic acid did not affect HIV expression. Indomethacin (100 microM) did not affect UV- or cis-Pt-induced HIV expression. These results suggest a role for the prostaglandins or the cyclo-oxygenase pathway or both in HIV induction mediated by DNA-damaging agents.

HIV expression is induced in dying cells.

Using HeLa cells stably transfected with an HIV-LTR-CAT construct, we demonstrated a peak in CAT induction that occurs in viable (but not necessarily cell-division-competent) cells 24 h following exposure to some cell-killing agents. gamma rays were the only cell-killing agent which did not induce HIV transcription; this can be attributed to the fact that gamma-ray-induced apoptotic death requires functional p53, which is not present in HeLa cells. For all other agents, HIV-LTR induction was dose-dependent and correlated with the amount of cell killing that occurred in the culture. Doses which caused over 99% cell killing induced HIV-LTR transcription maximally, demonstrating that cells that will go on to die by 14 days are the cells expressing HIV-LTR-CAT.

Cytokine and T-cell subset abnormalities in immunodeficient wasted mice.

Wasted mice bear an autosomal recessive mutation (wst/wst) that manifests itself in neurologic abnormalities, immunologic deficiency, and faulty DNA repair evident by 21 days of age. The immunodeficiency is characterized by a reduction in the thymus-to-body weight ratio, low levels of IgA plasma cells at secretory sites, and increased sensitivity of T-cells to the killing effects of ionizing radiation. Experiments were designed to examine measures of T-cell activity in wasted mice. The initial experiments established that wst/wst mice have percentages of thymic and splenic Thy1+ cells equivalent to those of control littermates. Further studies of T-cell subpopulations with thymocytes revealed normal percentages of CD4+ and CD8+ cells in wst/wst mice; however, double-labeling experiments showed that CD8+ cells were predominantly CD4- in wst/wst mice, whereas in controls most CD8+ cells also expressed CD4+. Mesenteric lymph node T-cell subpopulations were similar in wasted and control mice. Because cytokines play a significant role in the regulation of the immune response and also interact with a variety of cellular systems, we examined the expression of different cytokine and related genes (IL1, IL2, IL2R, TNF, IL5, gamma-interferon, beta-TGF) in lymphoid tissues from wasted mice as well as from littermate and parental controls. Studies of RNA from lymphoid tissues of wasted mice using dot blot and Northern blot hybridizations revealed a deficiency of IL5 mRNA in thymus and spleen, decreased expression of IL2R in thymus (but not spleen), increased expression of IL1 in spleen (but not thymus), and increased expression of IL2, gamma-interferon, and beta-TGF in both spleen and thymus, relative to controls. Expression of TNF mRNA in lymphoid tissues was unaffected by the wasted mutation. These results suggest a role for cytokine imbalance in the pathogenesis of the immunodeficiency and other abnormalities of wasted mice.

Invasive disease caused by Trichosporon beigelii.

An immunocompromised patient had cellulitis that was unresponsive to conventional antimicrobial therapy. Skin biopsy specimens and fungal blood cultures revealed the offending organism as Trichosporon beigelii. Recognition of this opportunistic pathogen in immunocompromised patients is important.

Hemosiderosis in a dialysis patient: treatment with hemofiltration and deferoxamine chelation therapy.

Although the highly permeable membranes utilized in hemofiltration are theoretically more permeable to deferoxamine-chelated iron than the standard cuprophan membranes used in conventional hemodialysis, no clinical data support this contention. Ours are the first published results of a preliminary short-term trial of combined therapy with deferoxamine and hemofiltration in a dialysis patient with hemosiderosis. An average of 15.3 mg of iron was mobilized with a 19.5-liter exchange over only 4 1/2 hours of postdilution hemofiltration. This compares favorable with previous reports in which 8 to 12 hours of dialysis were performed with Kiil dialyzers, and also with the 24-hour urinary excretion of chelated iron in iron-overloaded patients with normal renal function. We conclude that combined therapy with deferoxamine and hemofiltration offers promises as an effective means of iron mobilization in dialysis patients with hemosiderosis.

The effects of cisplatin and methotrexate on the expression of human immunodeficiency virus type 1 long terminal repeat.

Previous work by many groups has documented the induction of HIV-LTR (human immunodeficiency virus-long terminal repeat) following exposure of cells or whole animals to ultraviolet (UV) light and other DNA damaging agents. In these experiments we set out to determine whether exposure to the cancer chemotherapeutic agents methotrexate and cisplatin had any effect on the expression of the HIV-LTR. Using HeLa cells stably transfected with a construct in which HIV-LTR drives the expression of the reporter gene chloramphenicol acetyl transferase (CAT), we demonstrated induction of HIV-LTR 24-48 h following exposure to 50 microM cisplatin. When UV exposure (10 Jm-2) was coupled with cisplatin (50 microM) treatment (which also causes DNA damage), HIV-LTR induction was additive relative to either treatment alone. Methotrexate, which depletes the medium of tetrahydrofolate and does not induce DNA damage, induced HIV-LTR at later (6-7 days) time points than cisplatin or UV treatments. When methotrexate (128 microM) and UV (10 Jm-2) treatments were combined, the agents were synergistic with regard to HIV induction. For both drugs, though, induction was not due to generalized transcriptional activation since both cisplatin and methotrexate induced a repression of total transcription as measured in nuclear run-on assays.

Molecular analysis of viridans and nutritionally deficient (variant) streptococci causing sequential episodes of endocarditis in a patient.

Clinical blood isolates from sequential episodes of endocarditis occurring over a six-month period of time in an addict were investigated. The pathogens were Streptococcus sanguis II, Streptococcus mitis, and a nutritionally deficient (variant) streptococcus. The authors determined the DNA relatedness of these isolates by antibiograms, plasmid profiles, chromosomal endonuclease restriction digestions, and dot blot DNA-DNA hybridization analyses. The S. sanguis II and nutritionally deficient streptococcal strain had similar antibiograms being resistant to penicillin; neither produced beta-lactamase. No plasmids were found. The restriction endonuclease chromosomal digestion patterns of these isolates were unique and epidemiologically unrelated to each other. Dot blot DNA-DNA hybridizations, using the nutritionally deficient streptococcal DNA as the probe, showed homology to the preceding clinical isolates, S. sanguis II and S. mitis, at 15.4% and 45.1% hybridization levels, respectively. The nutritionally deficient streptococcus was only 4.2% homologous to a S. mitis ATCC strain and another nutritionally deficient streptococci isolate. Therefore, this patient had endocarditis with three distinct streptococcal strains.

A double-blinded comparative evaluation of three media for chromophore testing with viridans and nutritionally variant (deficient) streptococci.

A double-blinded prospective comparison of chromophore testing among 109 clinical isolates of alpha-hemolytic gram-positive cocci and 48 strains of nutritionally variant (deficient) streptococci (NVS) for its sensitivity, specificity, and predictive value under stimulated clinical laboratory conditions was performed after growth in three different media--Todd-Hewitt broth supplemented with 10 micrograms/mL of pyridoxal (THBP), THBP with 0.8% (w/v) yeast-extract (THBP + YE), and a semisynthetic chemically defined medium with Todd-Hewitt dialyzate (CDMT). The chromophore detection rates of Streptococcus mitis were 60.7, 67.9, and 78.6% after growth in THBP, THBP + YE, and CDMT, respectively. After growth in THBP there was significantly lower chromophore detection than either THBP + YE or CDMT for NVS (P less than 0.001), with a trend toward significantly less detection for S. mitis (0.15 greater than P). For Streptococcus sanguis II the detection rates were 45.7, 57.1, and 54.3%, respectively, for each medium. There was no significant difference between the detection rates after growth in THBP + YE or CDMT. One NVS was persistently chromophore negative, the first so described. There was a similar number of presumably false positive chromophore S. sanguis I strains (3 of 12) detected after growth in THBP + YE or CDMT. The sensitivity of chromophore detection for NVS (pooling results in THBP + YE and CDMT) was 95.8% and specificity was 59.6%. For a nonvariant streptococcus, the sensitivity was 61.9% and specificity was 93.5% for an isolate to be either S. mitis or S. sanguis II.

Low doses of neutrons induce changes in gene expression.

Studies were designed to identify genes induced in fibroblasts after exposure to low-dose neutron radiation but not after gamma rays. Our past work had shown similar modulation of transcripts for alpha-tubulin, beta- and gamma-actins, ornithine decarboxylase and interleukin 1 after exposure to either neutrons or gamma rays. However, differences in the expression of beta-protein kinase C and c-fos genes were observed, with both being induced after exposure to gamma rays but not neutrons. Recently we have identified two genes that are induced after exposure to neutrons but not gamma rays: Rp-8 (a gene associated with apoptosis) and the long terminal repeat (LTR) of the human immunodeficiency virus (HIV). Induction of Rp-8 mRNA was demonstrated in Syrian hamster embryo (SHE) fibroblasts and was found to be induced in cells exposed to neutrons administered at low (0.005 Gy/min) and high dose rate (0.12 Gy/min). No induction of other genes associated with apoptosis such as Rp-2, bcl-2 and Tcl-30 was observed. The induction of transcription from the LTR of HIV was demonstrated in HeLa cells bearing a transfected construct of the chloramphenicol acetyl transferase (CAT) gene driven by the HIV-LTR promoter. Measurements of CAT activity and CAT transcripts after irradiation demonstrated an unresponsiveness to gamma rays over a broad range of doses (0.1-3 Gy). Twofold induction of the HIV-LTR was detected after exposure to neutrons (0.48 Gy) administered at low (0.05 Gy/min) but not high (0.12 Gy/min) dose rates. Ultraviolet-mediated HIV-LTR induction, however, was inhibited by exposure to low-dose-rate neutron irradiation. These results are interesting in light of reports that Rp-8 is induced during apoptosis and that HIV causes apoptosis.

Effects of gamma rays, ultraviolet radiation, sunlight, microwaves and electromagnetic fields on gene expression mediated by human immunodeficiency virus promoter.

Previous work by our group and others has shown the modulation of human immunodeficiency virus (HIV) promoter or long terminal repeat (LTR) after exposure to neutrons and ultraviolet radiations. Using HeLa cells stably transfected with a construct containing the chloramphenicol acetyl transferase (CAT) gene, the transcription of which is mediated by the HIV-LTR, we designed experiments to examine the effects of exposure to different types of radiation (such as gamma rays, ultraviolet and sunlight irradiations, electromagnetic fields and microwaves) on HIV-LTR-driven expression of CAT. These results demonstrated ultraviolet-light-induced transcription from the HIV promoter, as has been shown by others. Exposure to other DNA-damaging agents such as gamma rays and sunlight (with limited exposures) had no significant effect on transcription mediated by HIV-LTR, suggesting that induction of HIV is not mediated by just any type of DNA damage but rather may require specific types of DNA damage. Microwaves did not cause cell killing when cells in culture were exposed in high volumes of medium, and the same cells showed no changes in expression. When microwave exposure was carried out in low volumes of medium (so that excessive heat was generated) induction of HIV-LTR transcription (as assayed by CAT activity) was evident. Electromagnetic field exposures had no effect on expression of HIV-LTR. These results demonstrate that not all types of radiation and not all DNA-damaging agents are capable of inducing HIV. We hypothesize that induction of HIV transcription may be mediated by several different signals after exposure to radiation.

Time kill curve analysis of vancomycin and rifampin alone and in combination against nine strains of nutritionally deficient streptococci.

Endocarditis caused by nutritionally deficient streptococci has a high bacteriologic and clinical failure rate, despite appropriate antimicrobial therapy. We investigated by time kill curve methodology nine clinical endocarditis isolates of nutritionally deficient streptococci to determine the in vitro efficacies of vancomycin and rifampin alone and in combination. The combination of vancomycin and rifampin demonstrated synergy and bactericidal activity in five of the strains. In one strain, this combination inhibited growth by greater than 2 log10 CFU/ml when compared to the growth control or either antibiotic alone, but it failed to be bactericidal. Indifference, defined as less than or equal to 2 log10 CFU per milliliter increase in killing of the combination compared to the next most active single agent, was demonstrated with the remaining three isolates. Changing the antibiotic concentrations in the time kill curve studies for these latter strains failed to demonstrate synergistic activity of the antibiotic combination. The vancomycin and rifampin combination may be a promising therapeutic modality for which in vivo correlation is indicated.

Genetic heterogeneity among nutritionally deficient streptococci.

The nutritionally deficient (variant) streptococci (NDS) share the auxotrophic characteristic of requiring pyridoxal or thiol group supplementation for growth. The deoxyribonucleic acid relatedness of these organisms among themselves is unknown. Improved speciation of NDS would lead to a better knowledge of their pathogenesis and possible insight into improved clinical management. Therefore, DNA-DNA hybridization and biotyping of 23 nutritionally deficient streptococci were performed. Biochemical testing using the API Rapid Strept Identification method revealed that the organisms in this study were characterized among three broad biotype groups. Only one strain was nontypeable. DNA-DNA hybridization among the nutritionally deficient streptococci that we compared revealed genetic heterogeneity. Only four (17%) of 23 isolates were highly homologous; all were of biotypes 2 and 3. Reference viridans streptococcal strains had minimal homology to the NDS strains. The data indicate that the NDS are genetically heterogeneous.

Group G Streptococci: susceptibility patterns and the effect of the inoculum size and growth phase on the bactericidal activity of penicillin.

Twenty-seven independent group G streptococcal isolates were studied by in vitro susceptibility testing against 22 different antimicrobial agents. Penicillin with a MIC90 of 0.03 micrograms/ml and ampicillin with a MIC90 of less than or equal to 0.015 micrograms/ml remain the agents of first choice for treatment of group G streptococcal infections. Tolerance was not demonstrated using the macrobroth dilution method in four media, Todd-Hewitt, Mueller-Hinton, Mueller-Hinton (cation-supplemented), and Tryptose Phosphate broths. Multiple regression analyses of time-kill curves of group G streptococci showed that the rate of cell death with penicillin at 0.04 micrograms/ml (five times greater than each organism's MIC) for both logarithmic- and stationary-phase cells with low-inocula were the same, but were five to six times greater in rate of death compared to the high-inocula cultures. Increasing the concentration to 1 microgram/ml of penicillin (125 times greater than each organism's MIC) did not significantly affect the rate of cell death for low-inocula cultures of either phase. Therefore, the size of the inoculum was found to be more significant than the phase of bacterial growth. These findings may explain the therapeutic discrepancy of relapses or prolonged group G streptococcal infections despite the organism being susceptible to the given antibiotic.

The hemolysin/bacteriocin produced by enterococci is a marker of pathogenicity.

The hemolysin/bacteriocin produced by some strains of Enterococcus faecalis is active in the lysis of human, rabbit, and horse erythrocytes, but not those from sheep. In this study, we determined that 20% of clinical enterococcal isolates tested in the clinical microbiology laboratory produced hemolysin and that pathogenic human E. faecalis were more likely to be hemolysin-producing isolates. Among the organisms isolated from different anatomic sites, variability in the degree of hemolysin production existed. We used an isogenic pair of E. faecalis organisms to demonstrate that hemolysin production was due to a hemolysin/bacteriocin determinant transmissible by a plasmid and was not strain dependent. This determinant may be linked to antibiotic resistance genes in some instances. Also, the erythrocyte lysis occurred only when hemolysin was in the presence of E. faecalis organisms, suggesting a bacterial cell dependency for activity of the hemolysin.

Candida lusitaniae--an opportunistic pathogen.

Candida lusitaniae is a newly recognized opportunistic pathogen amongst immunocompromised patients. The epidemiology and pathology remain largely unknown. This case report describes a 27-year-old female with vasculitis who acquired a fatal C. lusitaniae fungemia.

Human neutrophil oxidative response and phagocytic killing of clinical and laboratory strains of Enterococcus faecalis.

Many clinical isolates of Enterococcus faecalis produce a hemolysin/bacteriocin that is plasmid mediated. Recent human epidemiologic studies and animal research suggest that this hemolysin/bacteriocin may enhance the pathogenicity of hemolysin-producing enterococci compared with non-hemolysin-producing strains. These studies determined that clinical strains that produce hemolysin/bacteriocin differed from non-hemolysin-producing clinical and laboratory strains in their ability to induce the production of reactive oxygen intermediates in human peripheral blood neutrophils and in their susceptibility to phagocytic killing in vitro. The induction of superoxide anion generation by neutrophils was demonstrated to be directly proportional to the presence of the hemolysin/bacteriocin plasmid and was transferable to a non-hemolysin-producing laboratory strain by transconjugation. The presence of the plasmid, however, did not effect killing by phagocytic cells in vitro. It is proposed that hemolysin/bacteriocin-producing strains of enterococcus may be more pathogenic due to reactive oxygen product-induced tissue injury in vitro.

The effects of multiple UV exposures on HIV-LTR expression.

Previous studies have shown that cellular stress agents such as UV radiation induce transcription from the long terminal repeat (LTR) of the human immunodeficiency virus (HIV). Using HeLa cells stably transfected with the HIV-LTR sequence, which transcriptionally drives the chloramphenicol acetyl transferase (CAT) reporter gene, we examined the effects of multiple exposures to UVC (254 nm) on HIV-LTR-CAT expression. Low doses (< or = 5 J m-2) had no effect on CAT expression, but up to 29-fold induction was observed with 10 J m-2 when cells were harvested 48 h after completion of the exposure. Little difference was noted in induction levels when cells were exposed to one 25 J m-2 dose, viable cells were harvested at 24 h, 48 h or 72 h, and cell lysates were assayed for CAT expression. Two sequential 12.5 J m-2 exposures, given 24 h apart, resulted in an additive effect on CAT expression; these two exposures produced CAT activity equivalent to that induced following a single 25 J m-2 dose. This additive effect was not evident at the lower doses (< or = 5 J m-2) or at the higher doses. Maximal induction was observed using doses from 25 to 37.5 J m-2. Multiple exposures with either the low (< or = 5 J m-2) or high doses (> 25 J m-2) did not result in an additive effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of enhanced spontaneous and gamma-ray-induced apoptosis by lymphocytes of the wasted mouse.

Mice bearing the autosomal recessive mutation wasted (wst/wst) display a disease pattern including increased sensitivity of lymphocytes to ionizing radiation, neurologic dysfunction, and immunodeficiency. Many of the features of this mouse model have suggested a premature or increased spontaneous frequency of apoptosis in thymocytes. Past work has documented an inability to establish cultured T cell lines, and abnormally high death rate of stimulated T cells in culture, and an increased sensitivity of T cells to the killing effects of ionizing radiations in the wst/wst mouse relative to controls. The experiments reported here were designed to examine splenic and thymic lymphocytes from the wasted and control mouse for signs of early apoptosis. Our results revealed enhanced expression of Rp-8 mRNA (which has been associated with apoptosis) in thymic lymphocytes and to a lesser extent in spinal cord in the wst/wst mouse relative to controls; expression of Rp-2 and Tcl-30 mRNA (also reported to be induced during apoptosis) were not detectable in spleen or thymus. Expression of Rp-2, Rp-8, and Tcl-30 mRNA in other affected tissues of the wasted mouse (brain and liver) were similar in the wasted mouse and controls. Thymus and spleen from the wasted mouse have reduced numbers of viable cells relative to controls. Higher spontaneous DNA fragmentation was observed in lymphocytes from the wasted mouse than in controls; however, gamma-ray-induced DNA fragmentation peaked at a lower dose and occurred to a greater extent in lymphocytes derived from the wasted mouse relative to controls. These results suggest that high spontaneous and gamma-ray-induced apoptosis in T cells of the wasted mouse may contribute to the mechanism underlying the observed lymphocyte and DNA repair abnormalities.

Removal of cephalosporins by continuous arteriovenous ultrafiltration (CAVU) and hemofiltration (CAVH).

Cephalosporins are used with increasing frequency for sepsis treatment in patients receiving CAVU and CAVH. The different cephalosporins share the same basic molecular structure, yet they exhibit varied extent of plasma protein binding. Different amounts of the antibiotics may be removed by the ultrafiltration procedure because of these variations of physicochemical properties. We evaluated the sieving of eight new cephalosporins across the hemofilter membrane using an in vitro model. Bovine blood was perfused through polysulfone membranes at blood and ultrafiltrate flow rates of 100 and 20 ml/min respectively. Arterial plasma, venous plasma and ultrafiltrate drug concentrations were used to determine sieving coefficients. The sieving coefficients correlated well with the ultrafiltrate-arterial plasma drug concentration ratio (r = 0.679-0.972) but poorly with the extent of protein binding. Factors other than protein binding may therefore affect the drug sieving. Based on the findings, it was predicted that 0.2-21.9% of the daily cephalosporin dose may be removed by the CAVU and CAVH treatment. The need to alter drug dosages depends on the techniques of the ultrafiltration and hemofiltration procedure, the kinetics of the cephalosporins in patients, the sensitivity of the pathogen and the nature of the infection.