Risk factors for delirium among patients with advanced cancer in palliative care: a multicenter, patient-based registry cohort in South Korea.

OBJECTIVE: Previous studies have comprehensively investigated the prevalence and various potential risk factors for delirium among patients with advanced cancer admitted to the acute palliative care unit (APCU). Our objective was to evaluate the comprehensive association between delirium and various risk factors among patients with advanced cancer in an acute palliative care setting using a patient-based multicenter registry cohort. PATIENTS AND METHODS: We performed a multicenter, patient-based registry cohort study collected in South Korea between January 1, 2019, and December 31, 2020. Delirium was identified using a medical record review based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. RESULTS: In total, 2,124 eligible patients with advanced cancer in the APCU met the inclusion criteria. There were 127 out of 2,124 patients (prevalence, 6.0%; 95% CI, 5.0 to 7.1) with delirium during admission. Delirium in patients with advanced cancer was associated with age >70 years (OR, 1.793; 95% CI, 1.246 to 2.581), male sex (OR, 1.675; 95% CI, 1.131 to 2.479), no chemotherapy during hospitalization (OR, 2.019; 95% CI, 1.236 to 3.298), hearing impairment (OR, 3.566; 95% CI, 1.176 to 10.810), underweight (OR, 1.826; 95% CI, 1.067 to 3.124), current use of opioid medication (OR, 1.942; 95% CI, 1.264 to 2.982), previous history of delirium (OR, 12.497; 95% CI, 6.920 to 22.568), and mental illness (OR, 2.333; 95% CI, 1.251 to 4.352). CONCLUSIONS: In a large-scale multicenter patient-based registry cohort, delirium was associated with old age, male sex, no chemotherapy during hospitalization, hearing impairment, underweight, current use of opioid medication, and a history of delirium and mental illness. Our findings suggest physicians should pay attention to delirium in patients with advanced cancer admitted to the APCU with the above risk factors.

Regional reductions of transketolase in thiamine-deficient rat brain.

Thiamine deficiency impairs oxidative metabolism and causes metabolic encephalopathy. An early reduction in transketolase (TK) activity may be an important pathogenic event. To assess the role of TK, we have delineated the regional/cellular distribution of TK protein and mRNA in adult rat brain in pyrithiamine-induced thiamine deficiency. TK activity declined in both vulnerable and spared regions. Immunoblots showed a parallel reduction of TK protein. With a few exceptions, immunocytochemistry indicated an overall decline of TK immunoreactivity and the decrease was not specific to vulnerable areas. In contrast to the pronounced, general decline of TK protein, in situ hybridization revealed a regional decrease of 0-25% of TK mRNA in thiamine deficiency. Northern blots indicated a similar level of TK mRNA in whole brain in thiamine deficiency. These results show that the decline of TK activity results from a proportional decrease of TK protein, and the deficiency may be due to an instability of TK protein or an inhibition of TK mRNA translation. The lack of correlation of the distribution, and the absence of specific alteration, of TK in affected regions suggest that the reduced TK may not be linked directly to selective vulnerability in thiamine deficiency.

Heterogeneous expression of transketolase in rat brain.

Transketolase (TK; EC 2.2.1.1) is a key pentose phosphate shunt enzyme that plays an important role in the production of reducing equivalents and pentose sugars. TK activity declines in the brains of patients with Alzheimer's disease or Wernicke-Korsakoff syndrome, as well as in thiamine-deficient rats. Understanding the role of TK in the pathophysiology of these neurodegenerative conditions requires knowledge of its regional, cellular, and subcellular distribution within the brain. The current study employed in situ hybridization and immunocytochemistry to examine the distribution of TK mRNA and its encoded protein in adult rat brain. TK mRNA and protein were widely distributed throughout the brain. However, they were enriched in selective perikarya in the piriform cortex, nucleus of the diagonal band, red nucleus, dorsal raphe, pontine nucleus, locus coeruleus, trapezoid, inferior olive, and several cranial nerve nuclei. Lower expression of TK mRNA and protein occurred in layer V of cortex, olfactory tubercle, ventral pallidum, medial septal nucleus, hippocampus, thalamic and hypothalamic nuclei, mammillary body, central gray, and the substantia nigra. TK immunoreactivity also occurred in the nuclei of ubiquitously distributed glial cells, as well as ependymal cells. The heterogeneous distribution of TK may reflect a variety of metabolic activities among different brain regions but does not provide a simple molecular explanation for selective cell death in either thiamine deficiency or other conditions where TK is reduced.

An enzymatic and immunochemical analysis of transketolase in fibroblasts from Wernicke-Korsakoff syndrome.

Transketolase in cultured skin fibroblasts from three patients with Wernicke-Korsakoff syndrome (GM7504, 7505 and 7506) and matched controls was analyzed enzymatically and immunochemically with specific antisera generated against transketolase purified from human liver or red blood cells. The transketolase activity decreased by 45% in fibroblasts from the three Wernicke-Korsakoff patients, when compared to the activity in control cells. On immunoblots after SDS-PAGE, fibroblasts from the Wernicke-Korsakoff patients exhibited a 69-kDa species, a size similar to that of normal transketolase. The level of immunoreactivity was similar in the patient and control cells. The immunoblots of isoelectric focusing gels showed a major species of pI 8.6 with additional minor bands. However, the isoelectric focusing pattern of transketolase from the Wernicke-Korsakoff patients was also found in the majority of the control fibroblasts. Thus transketolase in fibroblasts from these Wernicke-Korsakoff patients is catalytically defective, but appears to be immunochemically normal.

Thiamin and Alzheimer's disease.

Because of clinical and neuropathological overlap between the characteristics of dementia of the Alzheimer type (DAT) and of a human thiamin deficiency syndrome (Wernicke-Korsakoff syndrome), thiamin pyrophosphate (TPP) dependent processes have been studied in DAT brain and other tissues. The activities of 3 TPP-dependent enzymes are reduced in DAT brain: transketolase (TK), the pyruvate dehydrogenase complex (PDHC), and the alpha-ketoglutarate dehydrogenase complex (KGDHC). Quantitatively, the most marked reductions are in KGDHC (to less than 20% of normal). In cultured skin fibroblasts, KGDHC activity is reduced to 50-60% of normal, TK activity to 80-90% of normal, and PDHC is normal. Structural and molecular studies of the DAT and non-DAT enzymes are in process. A lesion of KGDHC may be related to the pathogenesis of DAT. Treatment with large doses of thiamin has not been beneficial, but the data are not totally negative. Further studies of thiamin-dependent mechanisms in DAT seem justified.

Effect of chronic alcohol administration on transketolase in the brain and the liver of rats.

To estimate the nutritional and the pathological states in thiamin-deficiency-related diseases, especially Wernicke-Korsakoff syndrome, we studied the relationship among transketolase activity, transketolase concentration, and thiamin phosphate esters in rats chronically fed alcohol. In the brain of alcohol-fed rats, the enzyme activity and concentration decreased although there was no positive correlation between the two. On the contrary, transketolase activity in the liver correlated positively with concentration, and both transketolase activity and concentration were decreased in the thiamin-deficient groups. These findings suggest that transketolase in the brain may be different from that in the liver and that the alteration of the enzyme activity in the brain may be based on the conformational change of the protein molecule caused by chronic alcohol administration.

The relationship between the thiamin pyrophosphate effect and the saturation status of the transketolase with its coenzyme in human erythrocytes.

The thiamin pyrophosphate effect has been used as a reliable index to evaluate the nutritional status of thiamin. But there has not been any report concerning whether or not the thiamin pyrophosphate effect really reflects the saturation status of transketolase with thiamin pyrophosphate. In this report we studied the relationship between the thiamin pyrophosphate effect and the saturation status of transketolase. First, we determined the thiamin pyrophosphate concentrations, transketolase activities, thiamin pyrophosphate effects, and transketolase concentrations in human hemolysates from 16 apparently healthy subjects. The molar ratio of thiamin pyrophosphate to transketolase was in inverse proportion to the thiamin pyrophosphate effect. Second, we prepared apotransketolase preparations and reconstituted it with various concentrations of thiamin pyrophosphate. The thiamin pyrophosphate effects in these preparations were in good correspondence with the ratios of apotransketolase. These results indicate that the thiamin pyrophosphate effect really reflects the saturation status of transketolase with coenzyme.

Western blotting assay of transketolase concentration in human hemolysates.

Using a rabbit anti-human transketolase antiserum and Western blotting we can determine nanogram amounts of transketolase in human hemolysates quantitatively. Transketolase concentration in 18 apparently healthy subjects was 55.7 +/- 12.1 micrograms/g Hb (mean +/- SD). Transketolase concentration correlated positively with the enzyme activity both with and without in vitro addition of thiamin pyrophosphate. However, the former had a closer correlation (r = 0.8418, P less than 0.001) than the latter (r = 0.6703, P less than 0.01). A heavy drinker with an extremely low transketolase activity had proportionally low concentration to the activity. These results indicate that transketolase in hemolysates, whether it is holoenzyme or apoenzyme activated in vitro, has an identical specific activity among all subjects studied and that the reduced activity of transketolase in alcoholics is due to the reduced content of the enzyme protein. This method is applicable to study the dynamics and the abnormality of apotransketolase in human hemolysates.

Studies on the nature of thiamine pyrophosphate binding and dependency on divalent cations of transketolase from human erythrocytes.

1. The binding kinetics for [35S]thiamine pyrophosphate to transketolase and the dependency of transketolase on divalent cations for activity were investigated. 2. With Scatchard analysis, dissociation constant (Kd) and n value were calculated to be 0.2 x 10(-6) M and 0.66 respectively. 3. The activity of the reconstituted enzyme increased in the order of Co2+ less than Mn2+ less than Ca2+ less than Mg2+. The native transketolase contained Mg2+ in its molecular structure.