Introduction: Accurate diagnosis of thyrotoxicosis, a condition resulting from excessive thyroid hormone activity, is essential for appropriate management. However, access to diagnostic tools such as thyrotropin receptor antibody (TRAb) assays and thyroid ultrasonography remains limited in resource-constrained settings, highlighting the need for cost-effective alternatives. Recent studies suggest that the free triiodothyronine to free thyroxine (FT3/FT4) ratio may serve as a potential biomarker for differentiating the causes of thyrotoxicosis. Methodology: This cross-sectional study evaluated the FT3/FT4 ratio in newly diagnosed thyrotoxicosis patients aged ≥18 years recruited from Hospital Tengku Ampuan Rahimah, Hospital Banting, Klinik Kesihatan Pelabuhan Klang, and Klinik Kesihatan Pandamaran between February and December 2025. All participants underwent thyroid function testing (FT3, FT4, and TSH) and autoantibody assessment (TRAb and anti-thyroid peroxidase [anti-TPO]). Diagnostic performance of the FT3/FT4 ratio for Graves’ disease was assessed using receiver operating characteristic (ROC) curve analysis. Results: Fifty-eight patients were included, of whom 58.6% were diagnosed with Graves’ disease. Patients with Graves’ disease had significantly higher FT3 levels (median 16.8 pmol/L; IQR 10.9–25.7) compared to those with non-Graves’ thyrotoxicosis (median 8.3 pmol/L; IQR 5.3–13.5; p <0.001), with similar trends observed for FT4 levels (p <0.001). However, the FT3/ FT4 ratio did not differ significantly between groups (p >0.05), with an overall ROC AUC of 0.572, indicating poor discriminatory ability. Subgroup analysis based on FT4 levels improved performance; at FT4 <30 pmol/L, the FT3/FT4 ratio demonstrated 75.0% sensitivity, 91.7% specificity, and 87.5% diagnostic accuracy at a cutoff of 0.3445 (AUC = 0.813; 95% CI: 0.570–1.000; p = 0.069). No significant association was observed between the FT3/FT4 ratio and TRAb or anti-TPO. Conclusion The FT3/FT4 ratio has limited overall diagnostic utility but may provide adjunctive value in selected biochemical contexts, particularly in settings with limited access to immunological testing.
Diagnosis, Differential ; Thyroxine ; Triiodothyronine ; Thyrotoxicosis ; Cross-Sectional Studies

Introduction: Dopaminomas or dopamine-secreting pheochromocytomas are rare neuroendocrine tumors that frequently lack the classic paroxysmal symptoms of catecholamine excess (headache, sweating, palpitation). Diagnosing these tumors is exceptionally challenging when biochemical markers— specifically markedly elevated urinary dopamine—are interpreted in patients receiving exogenous Levodopa (L-DOPA) therapy, as the intake obscures clinical significance. Case: A 76-year-old male with ischemic heart disease, stage 4 chronic kidney disease, and new-onset hypertension was admitted for acute cholecystitis. Imaging studies incidentally revealed bilateral adrenal masses and demonstrated lipid-rich characteristics upon further evaluation with computed tomography (CT) adrenal washout. Biochemical evaluation revealed extreme elevations in 24-hour urinary dopamine (47,534 nmol/24 hours; normal <3,237) and 3-methoxytyramine (18.93 µmol/24 hours; normal <2.60), whereas downstream urinary noradrenaline (5.0 nmol/24 hours; normal 71.5–505.3), adrenaline (4.0 nmol/24 hours; normal 9.2–122.3), normetanephrine (0.22 µmol/24 hours; normal 0.88–2.88), and metanephrine (0.25 µmol/24 hours; normal 0.33–1.53) levels were all significantly below their respective reference ranges. The diagnosis was complicated by the patient’s concurrent use of L-DOPA/Benserazide for flupentixol-induced parkinsonism. L-DOPA is a direct precursor to dopamine; its administration can cause massive, false-positive elevations in urinary dopamine, mimicking a dopaminoma’s biochemical signature. However, the unique combination of profoundly high dopamine alongside suppressed downstream catecholamines and metanephrines suggested a true dopaminesecreting tumor—potentially secondary to dopamine beta-hydroxylase (DBH) deficiency—rather than drug interference. Conclusion This case illustrates the profound difficulty in diagnosing dopaminoma when exogenous L-DOPA therapy creates a near-identical biochemical profile. The diagnostic dilemma is further amplified by vague symptomatology, multiple comorbidities, and non-suggestive imaging. However, the finding of isolated dopamine hypersecretion with suppressed metanephrines serves as a critical clinical clue. This pattern points toward an intratumoral biosynthetic defect rather than drug interference. Clinicians must maintain a high index of suspicion and perform meticulous biochemical fractionation to identify these rare, dopamineisolated secreting tumors.
Dopamine ; Levodopa

Introduction: Thyroid stimulating hormone (TSH) suppression following differentiated thyroid carcinoma is widely recommended to reduce recurrence risk. However, this strategy assumes cardiovascular tolerance to supraphysiologic thyroid hormone exposure. In patients with advanced structural heart disease, this assumption may fail, exposing a critical limitation of guideline-directed TSH suppression. Case: We report a 71-year-old male with end-stage renal failure on hemodialysis and severe ischemic cardiomyopathy (ejection fraction 23%) who presented with acute decompensation characterized by dyspnea, rapid atrial fibrillation, and non–ST-elevation myocardial infarction. He had a history of papillary thyroid carcinoma treated with total thyroidectomy and radioactive iodine over 20 years prior and was maintained on levothyroxine 200 mcg daily for TSH suppression. Despite biochemically euthyroid indices (TSH 1.8 mIU/L, free thyroxine 4 17 pmol/L), he developed recurrent arrhythmia with heart failure decompensation. This case highlights a dissociation between biochemical euthyroidism and tissue-level thyrotoxicity in a structurally compromised myocardium. Papillary thyroid carcinoma after definitive therapy typically follows an indolent course with low short-term mortality. In contrast, in severe left ventricular dysfunction, excess thyroid hormone increases adrenergic sensitivity and myocardial oxygen demand, precipitating arrhythmia and ischemia. This risk is amplified in end-stage renal disease, where altered hormone handling renders biochemical indices less reliable. Conclusion Biochemical euthyroidism does not equate to physiological safety. In patients with advanced cardiovascular disease, thyroid hormone therapy should be titrated to cardiovascular tolerance rather than oncologic targets alone, and routine TSH suppression may be inappropriate.
Thyroxine ; Heart Failure ; Thyrotropin

OBJECTIVE: To investigate the effects of Bushen Huoxue Granule on the ubiquitin-proteasome system (UPS) in an in vitro model of Parkinson's disease. METHODS: After treated with 1-methyl-4-phenylpyridinium (MPP⁺, 1 mmol/L) for 24 h, the cells were incubated with drug-free serum, Madopar-containing serum or Bushen Huoxue Granule-containing serum (BCS, 5%, 10%, and 20%) for another 24 h. The levels of α-synuclein (α-syn), tyrosine hydroxylase (TH) and UPS-related proteins were detected by Western blot. The expression levels of α-syn in PC12 cells were also analyzed by Western blot after treated with proteasome inhibitor MG132 and WT-α-syn plasmid transfection, respectively, as well as the alterations induced by subsequent BCS intervention. Immunocytochemistry was performed to determine the changes in α-syn phosphorylation at serine 129 (pSer129-α-syn) expression. The 20S proteasome levels were measured by enzyme-linked immunosorbnent assay. RESULTS: BCS (volume fraction ⩽20%) intervention could alleviate the MMP⁺-induced cell viability decrease (P<0.05). In the MPP⁺ treated cells, α-syn was up-regulated, while TH and proteins of UPS such as ubiquitin (Ub), Ub binding with Ub-activating enzyme (UBE1), Parkin and Ub C-terminal hydrolase-1 (UCHL-1) were down-regulated (P<0.05). BCS intervention could attenuate the above changes (P<0.05). The activity of BCS on blocking α-syn accumulation was weakened by MG132 (P<0.05). While α-syn level was significantly increased in cells transfected with plasmid, and reduced by BCS intervention (P<0.05). pSer129-α-syn was increased in MPP⁺-induced PC12 cells, whereas decreased by later BCS intervention (P<0.05). The 20S proteasome activity of MPP⁺-induced PC12 cells was decreased, but increased after BCS intervention (P<0.05). CONCLUSION BCS intervention protected UPS function, increased 20S proteasome activity, promoted pathological α-syn clearance, restored cell viability, and reversed the damage caused by MPP⁺ in the in vitro model of Parkinson's disease.
PC12 Cells ; alpha-Synuclein/metabolism* ; Rats ; Animals ; 1-Methyl-4-phenylpyridinium/toxicity* ; Proteasome Endopeptidase Complex/metabolism* ; Drugs, Chinese Herbal/pharmacology* ; Ubiquitin/metabolism* ; Cell Survival/drug effects* ; Phosphorylation/drug effects* ; Tyrosine 3-Monooxygenase/metabolism*

OBJECTIVE: To investigate the antidepressant effects of Xiaoyao Pill (XYP) by exploring its interactions with gut microbiota and tryptophan metabolism. METHODS: Utilizing network pharmacology, the functional substance groups, key targets, and pathways of XYP in the treatment of depression were identified. The chronic unpredictable mild stress (CUMS) protocol was implemented in male Sprague-Dawley rats to establish depression model. Thirty rats were randomly divided into 3 groups according to their body weight (10 for each): control, CUMS and XYP groups (1.8 g/kg). After 28-day interventions, behavioral phenotyping including sucrose preference test (SPT) and open field test (OFT) were performed. Biochemical validation encompassed enzyme-linked immunosorbent assay for serum cortisol, hematoxylin-eosin histopathology, and immunohistochemistry. Liquid chromatography-mass spectrometry was utilized to profile serum metabolites, while fecal samples underwent metagenomic sequencing for gut microbiota characterization. RESULTS: Network pharmacology studies predicted that key components can protect the nervous system by regulating inflammatory pathways through the blood-brain barrier. SPT and OFT showed that XYP treatment significantly ameliorated depressive-like behaviors (all P<0.05). XYP treatment also restored hippocampal neuronal density, increased serum neurotransmitter levels of neurotransmitters such as 5-hydroxytryptamine and vasoactive intestinal peptide, and while suppressing inflammatory markers such as tumor necrosis factor-alpha, interleukin-1 beta (IL-1 β), and IL-6 (all P<0.05). Metagenomics revealed significant restructuring of gut microbiota, notably the regulation of Parabacteroides distasonis (P<0.05). Non-targeted metabolomics analysis showed that the level of metabolites in the tryptophan and kynurenine pathway significantly changed (variable importance in the projection >1, P<0.05), and the change of metabolic flux was significantly correlated with behavioral improvement (P<0.05). CONCLUSIONS XYP exerts antidepressant effects by increasing neurotransmitter levels, reducing inflammatory makers and modulating Parabacteroides distasonis. Through further exploration of metabolomics, we found that XYP may play a protective role in depression by regulating tryptophan metabolism.
Animals ; Tryptophan/metabolism* ; Drugs, Chinese Herbal/therapeutic use* ; Gastrointestinal Microbiome/drug effects* ; Rats, Sprague-Dawley ; Depression/blood* ; Male ; Stress, Psychological/drug therapy* ; Behavior, Animal/drug effects* ; Rats ; Chronic Disease ; Hippocampus/drug effects*

OBJECTIVE: To explore the inhibitory effects of Nardostachys Jatamansi DC. volatile oil (NJVO) on psychological factors substance P (SP)/cortisol (CORT)-induced hyperpigmentation. METHODS: The model of psychologically-induced hyperpigmentation of B16F10 cells was created using SP (10 nmol/L) + CORT (10 µmol/L) for 72 h. The levels of melanin content, tyrosinase (TYR) activity using NaOH lysis and L-dihydroxyphenylalanine (L-DOPA) oxidation methods were assessed, respectively. The effect of NJVO on SP/CORT-induced normal human skin tissue pigmentation was detected by Masson staining. Protein expressions of tyrosinase-related protein 1 (TRP-1), tyrosinase-relative protein 2 (DCT), and microphthalmia-associated transcription factor were determined using Western blot. The melanosome number, maturation, and melanosomal structure changes were detected through transmission electron microscopy and immunofluorescence experiments. In vivo, zebrafish pigment content was evaluated in SP/CORT-induced zebrafish hyperpigmentation model. RESULTS: NJVO significantly reduced the melanin content (P<0.01) and inhibited tyrosinase activity (P<0.01), the pigmentation of the normal skin tissue in the NJVO group was significantly lower than that in the SP/CORT group (P<0.05). And NJVO considerably downregulated expressions of melanogenesis-related proteins (TYR, TRP-1, DCT) in cells (P<0.01). In addition, the number of melanosomes was decreased and the dentrites formation of B16F10 cells was inhibited after NJVO treatment (P<0.01). In vivo, NJVO significantly reduced the pigment content in the zebrafish body (P<0.01). CONCLUSION NJVO effectively reversed SP/CORT-induced hyperpigmentation by suppressing the activity and expression of TYR and TRPs and inhibiting melanosome maturation in mouse B16F10 melanoma cells.
Animals ; Hyperpigmentation/psychology* ; Zebrafish ; Oils, Volatile/therapeutic use* ; Melanins/metabolism* ; Humans ; Monophenol Monooxygenase/metabolism* ; Mice ; Nardostachys/chemistry* ; Substance P ; Hydrocortisone ; Skin Pigmentation/drug effects* ; Cell Line, Tumor ; Melanosomes/ultrastructure* ; Microphthalmia-Associated Transcription Factor/metabolism* ; Melanoma, Experimental ; Oxidoreductases/metabolism* ; Intramolecular Oxidoreductases/metabolism*

The relationship between gut microbiota and depressive disorder has become a research focus in recent years. Within the microbiota-gut-brain axis, the gut microbiota influences the onset and progression of depressive disorder primarily through the tryptophan metabolic pathway. Tryptophan, an essential amino acid in humans, is subject to dual regulation by intestinal microorganisms, which modulate its metabolic balance via inflammatory stimulation and microbial metabolite production. In depression, excessive activation of the kynurenine branch of tryptophan metabolism leads to the accumulation of proinflammatory and neurotoxic metabolites, thereby exacerbating neuroinflammation in the brain. Intervention studies indicate that the antidepressant-like effects of probiotics and traditional Chinese medicine are associated with remodeling of the gut microbiota, restoration of tryptophan metabolic balance, and alleviation of neuroinflammation. Furthermore, targeted inhibition of kynurenine 3-monooxygenase can mitigate neuroinflammation by regulating microglial activity, thus improving depressive-like behaviors. In summary, the metabolite-inflammation axis represents a central node in the interaction regulation between tryptophan metabolism and the microbiota-gut-brain axis. This provides a theoretical foundation for developing novel therapeutic strategies targeting depression through modulation of gut microbiota-mediated tryptophan metabolism.
Tryptophan/metabolism* ; Gastrointestinal Microbiome/physiology* ; Humans ; Depressive Disorder/microbiology* ; Probiotics/therapeutic use* ; Brain/metabolism* ; Kynurenine/metabolism* ; Metabolic Networks and Pathways ; Animals ; Medicine, Chinese Traditional

Microorganisms inhabiting soils contaminated with heavy metals produce melanin, a dark brown pigment, as a survival strategy. In this study, a melanin-producing bacterium, Acinetobacter sp. ME1, with heavy metal tolerance and plant growth-promoting traits, was isolated from abandoned mine soil. Strain ME1 exhibited growth at concentrations of Zn up to 250 mg/L, Cd and Pb up to 100 mg/L, and Cr up to 50 mg/L. It had the ability to produce the plant hormone indole-3-acetic acid and siderophores along with 1-aminocyclopropane-1-carboxylic acid deaminase and protease activities. Additionally, it showed antioxidant activity, including catalase and 2,2-diphenyl-1-picryhydrazyl (DPPH) scavenging activities. The optimal conditions for melanin production by ME1 were a pH of 7 and a temperature of 35 ℃. At 1000 mg/L, ME1-extracted melanin exhibited DPPH radical scavenging activity of (25.040±0.007)%, a sun protection factor of 15.200±0.260, and 19.6% antibacterial activity against the plant pathogen Xanthomonas campestris. Furthermore, its adsorption capacity was (0.235±0.073) mg/g melanin for Zn and (0.277±0.008) mg/g melanin for Ni. In plants of Brassica chinensis grown under conditions of hydroponic cultivation with single heavy metal contamination of Cd, Zn, Pb, or Cr, the removal efficiency of each heavy metal was improved by 0.1‒1.8 times after 3 d following inoculation with the strain ME1 compared to the plants grown under the same conditions without inoculation. In addition, ME1 inoculation improved the removal efficiency of each heavy metal by 0.1‒1.0 times under multiple heavy metal contamination conditions. These findings suggest that Acinetobacter sp. ME1 could be used to enhance phytoremediation efficiency in heavy metal-contaminated soils. Moreover, the melanin it produces also holds promise in cosmetics, household products, and medical applications due to its photoprotective, antioxidant, and antimicrobial properties.
Acinetobacter/metabolism* ; Biodegradation, Environmental ; Metals, Heavy/metabolism* ; Melanins/metabolism* ; Soil Microbiology ; Antioxidants/metabolism* ; Plant Development ; Soil Pollutants/metabolism* ; Indoleacetic Acids/metabolism*

OBJECTIVES: To explore the correlation of serum tryptophan level with 90-day mortality risk in patients with hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF). METHODS: This retrospective study was conducted among 108 patients with HBV-ACLF, whose survival outcomes within 90 days after diagnosis were recorded. The correlation of baseline serum tryptophan levels measured by high-performance liquid chromatography with 90-day mortality of the patients was analyzed, and the predictive value of serum tryptophan for 90-day mortality was explored. RESULTS: Within 90 days after diagnosis, 53 (29.4%) of the patients died and 127 (70.6%) survived. The deceased patients had significantly lower baseline serum tryptophan levels than the survivors (7.31±3.73 pg/mL vs 13.32±7.15 pg/mL, P<0.001). Multivariate analysis suggested that serum tryptophan level was an independent factor correlated with mortality of HBV-ACLF after adjustment for confounding variables. The patients with serum tryptophan levels below the median level (10.14 pg/mL) at admission had significantly higher 90-day mortality risks than those with higher tryptophan levels (43.3% vs 15.6%, HR: 3.157, 95% CI: 1.713-5.817), and the complication by kidney dysfunction further increased the risk to 73.3% as compared with patients with higher serum tryptophan levels with normal kidney function (15.0%; HR: 7.558, 95% CI: 3.369-16.960). Serum tryptophan levels had an area under the receiver operating characteristic curve of 0.771 (95% CI: 0.699-0.844) for predicting 90-day mortality. CONCLUSIONS Serum tryptophan level is closely correlated with the survival outcomes of patients with HBV-ACLF, and a decreased tryptophan level indicates a high 90-day mortality risk, which can be further increased by the complication by kidney dysfunction.
Humans ; Tryptophan/blood* ; Retrospective Studies ; Acute-On-Chronic Liver Failure/virology* ; Male ; Female ; Middle Aged ; Adult ; Prognosis ; Hepatitis B/complications* ; Hepatitis B virus

OBJECTIVES: To investigate the effects of early life intervention with Bifidobacterium bifidum BD-1 (B. bifidum BD-1) on hyperactivity in a female mouse model of attention deficit hyperactivity disorder (ADHD) and explore the underlying mechanisms. METHODS: Eight newborn female Wistar-Kyoto (WKY) rats and 6 spontaneous hypertensive rats (SHRs) were gavaged with saline and another 6 SHRs were gavaged with B. bifidum BD-1 (10⁹ CFU) daily for 3 weeks. Open field test of the rats was conducted at 7 weeks, and fecal samples were collected at weaning (3 weeks) and at 7 weeks for 16S rRNA sequencing. Immunofluorescent staining was used to detect dopamine transporter (DAT) and tyrosine hydroxylase (Th) levels in the striatum and activated microglia in the prefrontal cortex. Treg cells in the mesenteric lymph nodes, spleen and blood were analyzed using flow cytometry. RESULTS: The SHRs traveled a significantly greater distance in open fields test than WKY rats, and this behavior was significantly attenuated by B. bifidum BD-1 intervention. The expression of DAT and Th in the striatum was significantly lower in the SHRs than in WKY rats, while B. bifidum BD-1 treatment obviously increased Th levels in the SHRs. B. bifidum BD-1 intervention significantly deceased the number of activated microglia and increased Treg cell counts in the spleen of SHRs. The treatment also enhanced α diversity in gut microbiota of the SHRs and resulted in a decreased Firmicutes/Bacteroidota ratio, more active Muribaculaceae growth, and suppression of Clostridia_UCG-014 proliferation. CONCLUSIONS Early life intervention with B. bifidum BD-1 alleviates hyperactivity in female SHRs by modulating the gut microbiota and peripheral immune response, suppressing neuroinflammation and improving dopaminergic system function. These findings provide evidence for early prevention strategies and support the development and application of psychobiotics for ADHD.
Animals ; Female ; Rats ; Rats, Inbred WKY ; Rats, Inbred SHR ; Attention Deficit Disorder with Hyperactivity/therapy* ; Bifidobacterium bifidum ; Probiotics/therapeutic use* ; Dopamine Plasma Membrane Transport Proteins/metabolism* ; Tyrosine 3-Monooxygenase/metabolism* ; Gastrointestinal Microbiome ; Disease Models, Animal