Thiamine utilization and the lack of prescribing standardization: A critical examination

OBJECTIVES

Thiamine is often prescribed for thiamine deficiency during hospitalization despite the lack of US-based clinical guidelines. This study aims to evaluate thiamine prescribing patterns and key characteristics associated with the deficiency to address gaps in care.

METHODS

Data were obtained from electronic health records of hospitalized patients between September 1, 2021, and March 30, 2022. Alcohol use disorder (AUD) was defined by a positive Clinical Institute Withdrawal Assessment score or a positive serum alcohol level upon admission. Geriatric patients were defined as age ≥65. Cohort 1 was defined as: AUD, albumin <4 g/L, INR >1.5, and total bilirubin >3 mg/dL. Cohort 2 was defined as: age >65, albumin <4 g/L, hemoglobin <15 g/dL, and folate <4 ng/mL. A multivariable LASSO regression model was used to identify characteristics associated with higher thiamine dosing (>100 mg/day).

RESULTS

Among 780 patients, 520 (66.7%) were identified as AUD, of which 265 (50.1%) were between the ages of 45-64 years. The AUD cohort was significantly different (p < 0.05) in the mean serum albumin 4.16 g/L (IQR: 3.8-4.5), AST 73.55 U/L (23.75-82.00), ALT 52.57 U/L (17.00-57.00), total bilirubin 0.98 (0.3-1.0), and INR 1.1 (0.99-1.12), compared to non-AUD patients with a mean serum albumin 3.75 g/L (3.3-4.2), AST 35.07 U/L (11.00-42.00), ALT 32.77 U/L (5.00-34.00), total bilirubin 0.89 (0.2-0.9), and INR 1.21 (1.0-1.22). In the geriatric cohort, 136 patients (17%) had a mean serum albumin 3.77 g/L (3.4-4.2), AST 38.66 U/L (14.0-41.0), ALT 29.36 U/L (9.0-37.0), total bilirubin 0.62 mg/dL (0.30-0.90), and direct bilirubin 0.12 mg/dL (0.00-0.20), compared to the non-geriatric cohort with a mean serum albumin 4.10 g/L (3.8-4.40), AST 66.44 U/L (21.0-75.0), ALT 50.03 U/L (16.00-53.75), total bilirubin 1.02 mg/dL (0.30-1.00), and direct bilirubin 0.31 mg/dL (0.00-0.20). In cohort 1, 40.6% patients were between 51 and 64 years old, (66.5%) male, and had a BMI <25 (36.4%). In cohort 2, 52.6% were between 65 and 70 years old, (57.9%) male, and had a BMI <25 (57.9%). Cohort 1 were prescribed a dose of 100 mg (47.7 %), oral (63.5%), intramuscular (18.2%), daily (58.9%), one-day duration (49.4%) most frequently. Cohort 2 were prescribed a dose of 100 mg (56.0%), oral (77.2%), daily (77.2%), one-day duration (29.8%) most frequently. The AUD was significantly associated with having a higher dosage (e.g., >100 mg) of thiamine prescribed per day OR 1.62 (1.11-2.37) (p < 0.01).

CONCLUSIONS

This study confirms that thiamine prescribing patterns vary during hospitalization and suggest specific laboratory findings may aid in identifying cohorts associated with the deficiency.

Single cell sequencing reveals endothelial plasticity with transient mesenchymal activation after myocardial infarction

 

After myocardial infarct (MI), followed by ischemia and scar formation, interstitial cells play key roles in the adaptation to injury. Endothelial cells (ECs), for instance, can clonally expand, migrate into the infarct area and facilitate crucial functions promoting revascularization, reestablishment of oxygen supply and secretion of paracrine factors. Moreover, ECs can transiently undergo changes towards a mesenchymal phenotype (Endothelial-to-mesenchymal transition; EndMT). Whether this process contributes to long-term cardiac fibrosis or helps to facilitate post-ischemic vessel growth remains controversial. Here, we aim to delineate kinetics and characteristics of phenotypic changes in ECs with single cell RNA-sequencing (scRNA-seq).

We performed a time course (homeostasis or 0 day (d), 1d, 3d, 5d, 7d, 14d, 28d post-MI) in mice and isolated the non-cardiomyocyte fraction for scRNA-seq (n=35,312 cells). Pecam1/Cdh5 double positive ECs showed expression of apoptosis, hypoxia and inflammation markers at 3d. Bioinformatic cell cycle analysis predicted high association with proliferative capacities at 3d, indicative of EC turnover post-MI. Metabolism, recently linked to regulate EndMT, was altered. We found genes of the glycolysis and the TCA-cycle pathway upregulated at 1d to 3d, and a decrease of fatty acid signaling genes. At 3d, mesenchymal markers Fn1, Vim, S100a4, Serpine1 transiently increased compared to homeostasis (&gt;1.6-fold, p&lt;0.05) together with a reduction of EC genes such as Pecam1. Interestingly, mesenchymal transition was transient and returned to baseline levels at 28d after MI. Cell fate trajectory analysis confirmed these findings by identifying an EC state characterized by high proliferation and mesenchymal but low EC properties. At 3d to 7d the majority of the ECs were assigned to this state, based on their transcriptomic profile.

We additionally used Cdh5-CreERT2; R26-mT/mG mice followed by scRNA-seq to trace the fate of ECs. Bioinformatic analysis of GFP-positive ECs confirmed the gain in mesenchymal marker but revealed no full transition to the mesenchymal state at later timepoints. This suggests a transient mesenchymal activation of ECs rather than a complete lineage transition. We further induced EndMT with TGF-β2 in ECs in vitro and observed reversibility of the phenotype after withdrawal of the stimulus. After treatment, ECs upregulated various mesenchymal marker genes. Withdrawal of TGF-β2 at 3d or 7d, reverted expression to baseline levels. We further determined DNA methylation of EndMT gene loci to assess if TGF-β2 leads to a true fate change but did not observe changes after TGF-β2 stimulation and withdrawal. Taken together, our data suggests that ECs undergo a transient mesenchymal activation concomitant with a metabolic adaptation early after MI but do not acquire a long-term mesenchymal fate. This activation may facilitate EC migration and clonal expansion to regenerate the vascular network.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Center of Cardiovascular Research (DZHK), Deutsche Forschungsgemeinschaft (DFG) CRC1366 Project B4

The False Hope of Becoming a Neuropsychologist. A Call for Action!

The Problem

According to the Census Bureau, the number of immigrants living in the US will increase to 69 million by 2060. Unfortunately, the number of international neuropsychologists who practice in the U.S. is behind in terms of this expected shift in the population. This is not due to a lack of interest - as many international students are accepted into neuropsychology doctoral programs each year. However, the acquisition of appropriate postdoctoral training proves to be a significant challenge. In general, the required two-year postdoctoral positions in neuropsychology are competitive, as they should be; however, international students are at a remarkable disadvantage. They cannot stay in the U.S. without a sponsor for a visa after a year of graduating, thus placing them in a disadvantaged state to secure a neuropsychology postdoctoral position.

The Impact

Given the projected population changes, neuropsychological assessments will have to be adjusted, new norms will need to be collected, and providers who speak non-English languages will be in higher demand. International neuropsychologists contribute to the field of neuropsychology through the addition of cultural competence, the enrichment in our understanding of cognition across racial and ethnic groups, and the development and selection of tests from a different perspective. In addition, they strengthen research pursuits, increase access to high-quality healthcare service to minorities, and provide quality service to non-English speaking patients. Finally, they can disseminate quality neuropsychological services throughout the world.

Call for Action

We encourage all neuropsychologists to create an action plan to support international students. There are many ways in which this could be accomplished: advocate to your human resource department to sponsor international students, educate yourself on the barriers and the process of sponsoring a work/training visa, and assist international students in strengthening their training experience with research, authorship, and collaboration.

A Randomized Trial of a Novel Chewable Multivitamin and Mineral Supplement Following Roux-en-Y Gastric Bypass

BACKGROUND

Vitamin and mineral deficiencies are common following Roux-en-Y gastric bypass (RYGB) and can lead to significant morbidity, but little research on the efficacy of vitamin supplementation regimens exists. We compared the efficacy and tolerability of an investigational versus a standard multivitamin regimen in patients undergoing RYGB.

METHODS

Fifty-six patients, aged 18 to 65, were randomized to an investigational versus a standard multivitamin. Plasma levels of vitamins A, B-12, D, E-α, E-β/γ, thiamine, folate, iron, iron-binding capacity, iron saturation, prealbumin, and parathyroid hormone (PTH) were measured at 3 and 6 months postoperatively. Proteins induced by vitamin K absence (PIVKA), beta-carotene, coenzyme Q10, and mixed tocopherols were measured at 3 months postoperatively. Primary outcomes were differences in plasma levels at 3 and 6 months. Secondary outcomes were palatability, ease of use, and adherence.

RESULTS

Twenty-one patients were randomized to the standard regimen and 26 to the investigational multivitamin. Nine were lost to follow-up. At 3 months, plasma levels of PTH were lower (p = 0.042), and levels of vitamin D (p = 0.033), thiamine (p = 0.009), and beta-carotene (p = 0.033) were higher in the investigational multivitamin arm compared to those in the standard regimen arm. Patients receiving the investigational multivitamin reported higher taste satisfaction than those receiving the standard regimen (p = 0.035).

CONCLUSION

The investigational multivitamin appears to be more effective than a standard multivitamin in maintaining therapeutic levels of clinically relevant vitamins and minerals, and was more palatable. Additional studies should be conducted to confirm these findings and refine the optimal dosing regimen.

TRIAL REGISTRATION

www.clinicaltrials.gov under identifier NCT01475617.

Retinoblastoma protein regulates the crosstalk between autophagy and apoptosis, and favors glioblastoma resistance to etoposide

Glioblastomas (GBMs) are devastating tumors of the central nervous system, with a poor prognosis of 1-year survival. This results from a high resistance of GBM tumor cells to current therapeutic options, including etoposide (VP-16). Understanding resistance mechanisms may thus open new therapeutic avenues. VP-16 is a topoisomerase inhibitor that causes replication fork stalling and, ultimately, the formation of DNA double-strand breaks and apoptotic cell death. Autophagy has been identified as a VP-16 treatment resistance mechanism in tumor cells. Retinoblastoma protein (RB) is a classical tumor suppressor owing to its role in G1/S cell cycle checkpoint, but recent data have shown RB participation in many other cellular functions, including, counterintuitively, negative regulation of apoptosis. As GBMs usually display an amplification of the EGFR signaling involving the RB protein pathway, we questioned whether RB might be involved in mechanisms of resistance of GBM cells to VP-16. We observed that RB silencing increased VP-16-induced DNA double-strand breaks and p53 activation. Moreover, RB knockdown increased VP-16-induced apoptosis in GBM cell lines and cancer stem cells, the latter being now recognized essential to resistance to treatments and recurrence. We also showed that VP-16 treatment induced autophagy, and that RB silencing impaired this process by inhibiting the fusion of autophagosomes with lysosomes. Taken together, our data suggest that RB silencing causes a blockage on the VP-16-induced autophagic flux, which is followed by apoptosis in GBM cell lines and in cancer stem cells. Therefore, we show here, for the first time, that RB represents a molecular link between autophagy and apoptosis, and a resistance marker in GBM, a discovery with potential importance for anticancer treatment.

Parasitological diagnosis of canine visceral leishmaniasis: is intact skin a good target?

The objective of this study was to evaluate intact skin of seroreactive dogs as a possible target for the parasitological confirmation of canine visceral leishmaniasis (CVL). For this purpose, 394 dogs identified in serological surveys carried out in the metropolitan region of Belo Horizonte were studied. Blood was collected from all animals for serology and a tissue sample was obtained from two sites for parasitological diagnosis. Skin obtained from the ear and scapular region was simultaneously analyzed in 247 animals and lesion samples and ear skin were analyzed in 147 dogs. Leishmania parasites were isolated from 310 (78.7%) animals, and all isolates were identified as Leishmania chagasi. Simultaneous isolation from two sites was possible in 240 of the 310 animals, including ear and scapular skin in 151/247 (61.1%) and ear skin and skin lesions in 89/147 (60.5%). Ours results suggest that intact skin is one of the main target sites for the parasitological confirmation of CVL in seroreactive dogs.

Genetic composition of human immunodeficiency virus type 1 in cerebrospinal fluid and blood without treatment and during failing antiretroviral therapy

Human immunodeficiency virus (HIV) infection of the central nervous system (CNS) is a significant cause of morbidity. The requirements for HIV adaptation to the CNS for neuropathogenesis and the value of CSF virus as a surrogate for virus activity in brain parenchyma are not well established. We studied 18 HIV-infected subjects, most with advanced immunodeficiency and some neurocognitive impairment but none with evidence of opportunistic infection or malignancy of the CNS. Clonal sequences of C2-V3 env and population sequences of pol from HIV RNA in cerebrospinal fluid (CSF) and plasma were correlated with clinical and virologic variables. Most (14 of 18) subjects had partitioning of C2-V3 sequences according to compartment, and 9 of 13 subjects with drug resistance exhibited discordant resistance patterns between the two compartments. Regression analyses identified three to seven positions in C2-V3 that discriminated CSF from plasma HIV. The presence of compartmental differences at one or more of the identified positions in C2-V3 was highly associated with the presence of discordant resistance (P = 0.007), reflecting the autonomous replication of HIV and the independent evolution of drug resistance in the CNS. Discordance of resistance was associated with severity of neurocognitive deficits (P = 0.07), while low nadir CD4 counts were linked both to the severity of neurocognitive deficits and to discordant resistance patterns (P = 0.05 and 0.09, respectively). These observations support the study of CSF HIV as an accessible surrogate for HIV virions in the brain, confirm the high frequency of discordant resistance in subjects with advanced disease in the absence of opportunistic infection or malignancy of the CNS, and begin to identify genetic patterns in HIV env associated with adaptation to the CNS.

Down-modulation of TCR/CD3 surface complexes after HIV-1 infection is associated with differential expression of the viral regulatory genes

We have investigated the mechanism(s) involved in progressive abrogation of CD3-gamma gene expression after HIV-1 or HIV-2 infection. A comparison of intracellular virus expression with T cell receptor surface density, revealed both high and low levels of viral p24 antigen in the TCR/CD3(hi), TCR/CD3(lo), and TCR/CD3(-) cells. Furthermore, in non-productively infected cells expressing the multiply spliced, virally encoded tat, rev, and nef regulatory gene transcripts, the same progressive loss of surface TCR/CD3 complexes was observed. We treated HIV-1-infected cells with antisense (AS) phosphorothioate oligodeoxynucleotides (P-OdN) targeted to the viral regulatory genes. All of the HIV-1 sequence-specific AS-P-OdN's inhibited intracellular p24 antigen expression in a time- and dose-dependent manner; although, blocking p24 expression alone was not sufficient to modulate TCR/CD3 surface density. Only Tat-AS and Nef-AS were able to delay TCR/CD3 down-modulation on receptor-positive cells or drive receptor up-regulation on receptor-negative cells. In contrast, Rev-AS accelerated TCR/CD3 loss on receptor-positive cells. RT-PCR revealed that Tat-AS and Nef-AS reduce the level of tat, nef, and rev transcripts, while Rev-AS increases the level of tat and nef transcripts in infected cells. Thus, when intracellular conditions favor expression of tat and/or nef in the absence of rev, CD3-gamma gene transcripts and TCR/CD3 surface density are down-modulated.

The effect of red wine on experimental atherosclerosis: lipid-independent protection

To assess the effect of red wine on atherosclerosis, New Zealand rabbits were given 1% cholesterol diet for 12 weeks and compared to animals that received the diet plus either red wine or nonalcoholic wine products (NAWP). Diet induced marked increases in total and LDL cholesterol; yet no significant changes in HDL and triglyceride concentrations occurred. In the control group, plaque area was 69 +/- 9% of the aortic surface, while in the wine and NAWP groups it was only 38 +/- 9 and 47 +/- 12%, respectively (P < 0.0001). The average intima/media thickness ratio was 0.60 +/- 0.2 in control animals, 0.14 +/- 0.09 in the wine group, and 0.39 +/- 0.19 in the NAWP group (P < 0.0001). No significant differences were noted in LDL oxidizability among treatments. Thus, both red wine and NAWP can prevent plaque formation in hypercholesterolemic rabbits despite significant increases in LDL. We speculate that anti-platelet effect, blockade of expression of endothelial cell adhesion molecules, and/or NO stimulation by red wine flavonoids are possible explanations.

Detection of HIV-RNA-positive monocytes in peripheral blood of HIV-positive patients by simultaneous flow cytometric analysis of intracellular HIV RNA and cellular immunophenotype

Determinations of plasma HIV viral RNA copy numbers help to define the kinetics of HIV-1 infection in vivo and to monitor antiretroviral therapy. However, questions remain regarding the identity of various infected cell types contributing to this free virus pool and to the in vivo lifecycle of HIV during disease progression. Characterization of a novel fluorescence in situ hybridization (FISH) assay employing a pool of labeled oligonucleotide probes directed against HIV RNA was done followed by coupling of the FISH assay with simultaneous surface immunophenotyping to address these questions. In vitro characterizations of this assay using tumor necrosis factor-alpha stimulated and unstimulated ACH-2 cells demonstrated the ability to detect < 5% HIV RNA positive cells with a sensitivity of < 30 RNA copies per cell. Peripheral blood mononuclear cells from 39 HIV-seropositive patients on no, single, combination, or triple drug therapy and 8 HIV-seronegative patients were examined. The majority of HIV-positive patients (24/39) harbored monocytes positive for HIV RNA and a significantly higher fraction of patients with high plasma viral load carried positive monocytes (13/16) than did patients in the low plasma viral load group (11/23). These results demonstrate the effectiveness of a novel FISH assay for identifying and monitoring HIV-infected cell populations in the peripheral blood of HIV-positive patients. In addition, monocytes are a major source of cellular HIV virus in the peripheral blood of HIV patients, even with progression of disease.

Adoptive immunotherapy for leukemia: donor lymphocytes transduced with the herpes simplex thymidine kinase gene for remission induction. HGTRI 0103

This study will evaluate the safety and efficacy of allogenic donor lymphocyte infusions in patients who have relapsed hematologic malignancies after allogeneic bone marrow transplantation (BMT). Donor lymphocyte transfusions have resulted in the cure of some patients with relapsed leukemia or lymphoproliferative disorder after allogeneic BMT, but has been complicated by the development of graft versus host disease (GvHD). We hypothesize that a retroviral vector containing the Herpes simplex thymidine kinase (HStk) gene will allow for retention of the anti-leukemia response of transfused donor lymphocytes while allowing for the adverse effects of GVHD to be mitigated. Patients with relapsed hematologic malignancies after allogeneic BMT will be infused with ex vivo gene modified donor lymphocytes. The Herpes Simplex thymidine kinase (HStk) gene will be transduced into the cells ex vivo using LTKOSN. 1 vector supernate. Insertion of the HStk gene into lymphocytes confers a sensitivity to the anti-herpes drug ganciclovir (GCV). This selective destruction of donor lymphocytes in situ will be used to abrogate the effect of graft versus host disease, if it develops.

Genetic differences between blood- and brain-derived viral sequences from human immunodeficiency virus type 1-infected patients: evidence of conserved elements in the V3 region of the envelope protein of brain-derived sequences

Human immunodeficiency virus type 1 (HIV-1) sequences were generated from blood and from brain tissue obtained by stereotactic biopsy from six patients undergoing a diagnostic neurosurgical procedure. Proviral DNA was directly amplified by nested PCR, and 8 to 36 clones from each sample were sequenced. Phylogenetic analysis of intrapatient envelope V3-V5 region HIV-1 DNA sequence sets revealed that brain viral sequences were clustered relative to the blood viral sequences, suggestive of tissue-specific compartmentalization of the virus in four of the six cases. In the other two cases, the blood and brain virus sequences were intermingled in the phylogenetic analyses, suggesting trafficking of virus between the two tissues. Slide-based PCR-driven in situ hybridization of two of the patients' brain biopsy samples confirmed our interpretation of the intrapatient phylogenetic analyses. Interpatient V3 region brain-derived sequence distances were significantly less than blood-derived sequence distances. Relative to the tip of the loop, the set of brain-derived viral sequences had a tendency towards negative or neutral charge compared with the set of blood-derived viral sequences. Entropy calculations were used as a measure of the variability at each position in alignments of blood and brain viral sequences. A relatively conserved set of positions were found, with a significantly lower entropy in the brain-than in the blood-derived viral sequences. These sites constitute a brain "signature pattern," or a noncontiguous set of amino acids in the V3 region conserved in viral sequences derived from brain tissue. This brain-derived signature pattern was also well preserved among isolates previously characterized in vitro as macrophage tropic. Macrophage-monocyte tropism may be the biological constraint that results in the conservation of the viral brain signature pattern.

HIV-1 sequence variation between isolates from mother-infant transmission pairs

To examine the sequence diversity of human immunodeficiency virus type 1 (HIV-1) between known transmission sets, sequences from the V3 and V4-V5 region of the envelope gene from four mother-infant pairs were analyzed. The mean interpatient sequence variation between isolates from linked mother-infant pairs was comparable to the sequence diversity found between isolates from other close contacts. The mean intrapatient variation was significantly less in the infants' isolates then the isolates from both their mothers and other characterized intrapatient sequence sets. In addition, a distinct and characteristic difference in the glycosylation pattern preceding the V3 loop was found between each linked transmission pair. These findings indicate that selection of specific genotypic variants, which may play a role in some direct transmission sets, and the duration of infection are important factors in the degree of diversity seen between the sequence sets.

Complementation of adenovirus virus-associated RNA I gene deletion by expression of a mutant eukaryotic translation initiation factor

Adenovirus VA RNAs (virus-associated RNAs) are small polymerase III transcripts that are required for efficient initiation of mRNA translation late in adenovirus infection. VAI RNA prevents double-stranded RNA (dsRNA) activation of the interferon-induced protein kinase (DAI kinase). Activation of this kinase results in phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF-2 alpha) and correlates with inhibition of translation initiation. In this report we show growth complementation of adenoviruses harboring deletions in the VAI gene in cell lines expressing a serine-to-alanine mutant of eIF-2 alpha. This serine-to-alanine mutant is resistant to phosphorylation by DAI kinase. These results directly show that the primary function of VAI RNA in the lytic adenovirus infection is the inhibition of eIF-2 alpha phosphorylation by DAI kinase and identify eIF-2 alpha as the target that mediates the effects of DAI kinase activation. Cells that express a mutant eIF-2 alpha will enable the isolation of specific host-range mutants for other types of viruses that are defective in the ability to inhibit DAI kinase.

Antibiotic sensitivity of enteropathogenic bacteria isolated from patients in a Sharjah hospital

In recent years widespread circulation of salmonella and shigella strains resistant to multiple antibiotics has become an international problem. Accordingly the bacterial sensitivity to a range of antibiotics has been assessed in vitro and recorded for the period 1979-83 for patients from the Al Qassimi Hospital. A total of 229 enteric pathogens from 148 children and 59 adult patients were isolated and studied. Most of the enterobacteria were sensitive to colistin, gentamicin, trimethoprim and chloramphenicol (Salmonella typhi approached 100% sensitivity). High rates of sensitivity were also found to ampicillin in S. typhi (96%) and other salmonella serotypes (85%), whilst only 57% of Shigella species and 14% of Escherichia coli were sensitive to this antibiotic. Low rates of sensitivity to sulphamethoxazole, streptomycin and tetracycline were found in shigella and E. coli (ranging from 7 to 14%). Approximately 50% of S. typhi and other salmonella serotypes were sensitive to sulphamethoxazole and streptomycin and 80% to tetracycline. Resistance to three or more antibiotics was very common in shigella and enteropathogenic strains of E. coli (74-85%), less common in non-typhoid salmonella (29%) and exceptional in S. typhi strains. In general, shigella and E. coli isolates showed a high rate of resistance to several antibiotics, whilst S. typhi and other salmonella serotypes retained their original sensitivity to most of the antibiotics used in clinical practice.