Effect of diazoxide on a cat with insulinoma.

Case summary: The patient was a castrated male American Shorthair cat, approximately 14 years old, weighing 3.4 kg. The patient had chronic kidney disease (CKD) (International Renal Interest Society stages 3-4) as an underlying disease. The cat was examined at a hospital for intermittent lethargy and seizures. Hypoglycaemia was repeatedly observed, and the insulin level was 1.78 ng/ml (reference interval 0.27-0.69) when the blood glucose was 49 mg/dl. Although the cat was tentatively diagnosed with insulinoma, surgery was not recommended because of the severe CKD. Although frequent feeding and prednisolone treatment were initially attempted, blood glucose decreased to 24-42 mg/dl. Diazoxide was additionally prescribed at a dose of 5.2 mg/kg q12h. The cat's clinical signs improved, and the blood glucose was in the range of 75-103 mg/dl during the first 2 months. It was maintained at >50 mg/dl until the patient died of renal failure 161 days after the start of diazoxide treatment. With regard to adverse events, vomiting once every 2-3 days without weight loss and non-regenerative anaemia were observed, which might have been at least partially caused by diazoxide treatment. An insulinoma was definitively diagnosed via pathological autopsy. Relevance and novel information: This is the first reported case of long-term treatment with diazoxide in a cat with insulinoma. Since it was effective in situations where conventional therapies were unsuccessful, diazoxide could be useful as a new therapeutic option for cats with insulinoma. Since adverse events, such as progression of vomiting frequency and non-regenerative anaemia, were observed, careful monitoring was required during administration.

8-Hydroxy-2'-deoxyguanosine and malondialdehyde in plasma and their association with disease severity in 20 cats with chronic kidney disease.

OBJECTIVES: Oxidative stress is associated with the development and progression of chronic kidney disease (CKD) in humans. The aim of this study was to evaluate the concentrations of oxidative stress markers, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA), in the plasma and urine of cats with different stages of CKD. METHODS: Plasma and urine samples were collected from cats with CKD that were referred to the Veterinary Medical Center of the University of Tokyo between April 2019 and October 2022. Plasma and urine samples were collected from healthy cats (n = 6 at most), cats with stage 2 CKD (n = 8) and stage 3-4 CKD (n = 12), and cats with idiopathic cystitis (disease control, n = 5). Plasma and urine concentrations of 8-OHdG and MDA were measured using ELISA and thiobarbituric acid reactive substances assay kits, respectively. RESULTS: The median plasma 8-OHdG concentrations were 0.156 ng/ml (<0.125-0.210 ng/ml) in the healthy group, <0.125 ng/ml (range <0.125 ng/ml) in the idiopathic cystitis group, 0.246 ng/ml (range 0.170-0.403 ng/ml) in cats with stage 2 CKD and 0.433 ng/ml (range 0.209-1.052 ng/ml) in cats with stage 3-4 CKD. Concentrations in stage 3-4 CKD were significantly higher than those in the healthy and disease control groups. Plasma MDA concentrations were low in the healthy and disease control groups and significantly higher in cats with stage 3-4 CKD. In every cat with CKD, plasma 8-OHdG and MDA concentrations were positively correlated with plasma creatinine concentrations (8-OHdG, rs = 0.68; MDA, rs = 0.67). Urinary 8-OHdG/urinary creatinine (u-CRE) and urinary MDA/u-CRE levels did not differ significantly between the groups; however, it was difficult to evaluate them because of the small sample size. CONCLUSIONS AND RELEVANCE: This report shows that plasma 8-OHdG and MDA concentrations increase with the severity of feline CKD. These markers may be useful for assessing oxidative stress in cats with CKD.

Relationship between cerebral blood flow reduction patterns on scintigraphy and nonmotor symptoms in new-onset Lewy body disease.

BACKGROUND: This study aimed to investigate the relationship between patterns of reduced cerebral blood flow (CBF) evaluated by means of 123I-N-isopropyl-p-iodoamphetamine ([123I]IMP) scintigraphy and nonmotor symptoms in new-onset Lewy body disease (Parkinson's disease and dementia with Lewy bodies [DLB]). MATERIAL AND METHODS: Twenty-four patients diagnosed with new-onset Parkinson's disease or DLB underwent [123I]IMP CBF scintigraphy at St. Marianna Medical University Hospital between January 1, 2010, and March 30, 2018. The reductions in CBF in various brain regions were analyzed using the three-dimensional stereotactic surface projection method and were compared to standard database values, yielding extent values (%). The extent values were evaluated in relation to the presence/absence of motor or nonmotor symptoms such as visual hallucinations, auditory hallucinations, delirium, depression, delusions, and dementia. RESULTS: The extent value was 100% in the angular, supramarginal, and lingual gyri; 95% in the orbital gyri; and 92.6% in the fusiform gyri. The extent value in patients without hallucinations and those with visual hallucinations was 41.2% and 54.3%, respectively, in the frontal lobe (p = 0.02) and 33.3% and 51.0%, respectively, in the medial prefrontal gyri (p = 0.02). Age-adjusted multivariate analysis showed that extent values in the frontal lobe were associated with visual hallucinations (odds ratio: 1.09, 95% confidence interval 1.00-1.18, p = 0.04). CONCLUSIONS: The above results show that the CBF is reduced in several areas of the cerebral cortex and suggest an association between reduced blood flow in the frontal lobe and the appearance of visual hallucinations in patients with new-onset DLB.

Preparation of Solifenacin Succinate Functional Particles Embedded in a Gelling-Swelling Layer (PEGS) and Their Formulation in Orally Disintegrating Tablets.

The purpose of this research was firstly to prepare solifenacin succinate functional particles embedded in a gelling-swelling layer (PEGS) so as to achieve both taste-masking of the unpleasant taste of the drug and rapid drug elution, and secondly to incorporate these PEGS into orally disintegrating tablets (ODTs). In in vitro dissolution tests, initial drug release from the prepared PEGS could be suppressed to less than 1% after 2 min and increased to more than 85% after 30 min by adjusting the composition of the PEGS, in particular the thickness of the outer water-penetration control layer which contains a water-insoluble polymer. For the preparation of ODTs containing PEGS, a semi-direct compression method was adopted in order to prevent damage to the PEGS by processes such as granulation or compaction. The use of a fibre-shaped microcrystalline cellulose with poor fluidity improved the content uniformity of the ODTs, as the crystal fibres became entangled with the PEGS and other additives. The use of spherical mannitol with a hollow structure produced by spray drying imparted relatively high hardness and rapid disintegration properties to the final ODTs containing PEGS, which were tableted using a low compression force. There was no significant difference in the drug-release profiles of the optimally formulated ODTs containing PEGS tableted at different compression forces. The ODTs containing PEGS maintained a drug-release lag time sufficient for taste-masking of solifenacin succinate.

Preparation of Novel Functional Drug Particles Embedded in a Gelling-Swelling Layer (PEGS) for Taste Masking and Subsequent Rapid Drug Release.

The purpose of this research was to develop novel functional drug particles embedded in a gelling-swelling layer (PEGS) which are capable of achieving both taste-masking of unpalatable drugs and rapid drug elution. The functional particles had a three-layer structure consisting of a core drug layer, a gelling-swelling layer and an outer water-penetration control layer containing a water-insoluble polymer. The concept of formulation design was as follows: when water reaches the gelling-swelling layer, pulverized fine gelling-swelling particles gellate and swell from water absorption to form a rigid layer, thereby preventing drug release. After a defined lag time, the increased volume of the gelling-swelling layer breaks down the outer water-penetration control layer, leading to rapid drug release. In order to adapt this system for use in orally disintegrating tablets, PEGS were prepared at a size of about 250 µm using a fine particle-coating method. Ambroxol hydrochloride was used as a model drug for bitterness and the effects of different gelling-swelling agents and water-insoluble polymers on drug release characteristics from PEGS were examined. In in vitro dissolution tests, it was shown that the drug dissolution rate from PEGS could be suppressed to about 5% after 2 min and increased to more than 85% after 30 min by adjusting the composition and thickness of the outer layer. The PEGS expanded about 1.5-fold and the outer layer was ruptured after 5 min in water.

Mini Review: Anticholinergic Activity as a Behavioral Pathology of Lewy Body Disease and Proposal of the Concept of "Anticholinergic Spectrum Disorders".

Given the relationship between anticholinergic activity (AA) and Alzheimer's disease (AD), we rereview our hypothesis of the endogenous appearance of AA in AD. Briefly, because acetylcholine (ACh) regulates not only cognitive function but also the inflammatory system, when ACh downregulation reaches a critical level, inflammation increases, triggering the appearance of cytokines with AA. Moreover, based on a case report of a patient with mild AD and slightly deteriorated ACh, we also speculate that AA can appear endogenously in Lewy body disease due to the dual action of the downregulation of ACh and hyperactivity of the hypothalamic-pituitary-adrenal axis. Based on these hypotheses, we consider AA to be a behavioral pathology of Lewy body disease. We also propose the concept of "anticholinergic spectrum disorders," which encompass a variety of conditions, including AD, Lewy body disease, and delirium. Finally, we suggest the prescription of cholinesterase inhibitors to patients in this spectrum of disorders to abolish AA by upregulating ACh.

Biodegradation of high concentrations of formaldehyde by lyophilized cells of Methylobacterium sp. FD1.

In the present study, Methylobacterium sp. FD1 utilizing formaldehyde was isolated from soil. The resting cells of FD1 degraded high concentrations of formaldehyde (~2.7 M) and produced formic acid and methanol that were molar equivalents of one-half of the degraded formaldehyde. This result suggests that formaldehyde degradation by FD1 is caused by formaldehyde dismutase. The optimal temperature and pH for formaldehyde degradation by the resting cells of FD1 were 40 °C and 5-7, respectively. The lyophilized cells of FD1 also degraded high concentrations of formaldehyde. The formaldehyde degradation activity of the lyophilized cells was maintained as the initial activity at 25 °C for 287 days. These results suggest that the lyophilized cells of FD1 are useful as formaldehyde degradation materials.

Serum Anticholinergic Activity as an Index of Anticholinergic Activity Load in Alzheimer's Disease.

We reported a procedure of serum anticholinergic activity (SAA) measurement and the reliability and reproducibility of the receptor binding assay, and we also described the usefulness of SAA measurement reflecting the anticholinergic activity (AA) in the central nervous system (CNS). According to the results of a 10 times repeated measurement of standard atropine binding, the relative error was between -5.5 and +3.7%, and we considered that measurement of SAA in our studies is accurate and validated. Downregulation of acetylcholine activates inflammation in both CNS and peripheral tissue, which causes AA in both sites. Therefore, changes of AA in the CNS link with SAA in the peripheral system even if a substance having AA does not penetrate through the blood-brain barrier. Then we redescribe issues that require attention in the measurement of SAA. It is generally defined that any SAA greater than the detection limit of a quantitative atropine equivalent level (≥1.95 nM in our study) is positive. According to previous studies, SAA is considered to be positive when its atropine equivalent is ≥1.95 nM and undetectable when this is <1.95 nM. Nevertheless, as a low SAA can act as AA in the CNS, we should assume that SAA might also be positive if its marker concentration is between 0 and 1.95 nM. In addition, SAA should be measured around 11 a.m. or somewhat later because of the diurnal rhythm of cortisol in humans.

Does Anticholinergic Activity Affect Neuropathology? Implication of Neuroinflammation in Alzheimer's Disease.

One characteristic neuropathological feature of Alzheimer's disease (AD) is profound neuronal loss in the nucleus basalis of Meynert, the major source of cholinergic innervation of the cerebral cortex. Clinically, anticholinergic activity causes a decline in cognitive function and increases the risk of dementia, thus possibly enhancing AD pathologies and neurodegeneration. Until now there has been insufficient human neuropathological data to support this conclusion. Experimental studies using a tauopathy mouse model demonstrated anticholinergics enhanced tau pathology and neurodegeneration corresponding to central anticholinergic activity. Additionally, donepezil, a cholinesterase inhibitor, ameliorated tau pathology and neurodegeneration in the same mouse model. These results indicate the balance between cholinergic and anticholinergic activities might affect neurodegeneration. Importantly, neurodegeneration observed in the mouse model seemed to correspond to the distribution of microglial activation, and it was reported that neuroinflammation plays an important role in the pathomechanism of AD, while anticholinergic activity augments inflammatory responses. Moreover, some studies indicated ß-amyloid itself depletes cholinergic function similarly to anticholinergic activity. Thus, anticholinergic activity might initiate and/or accelerate AD pathology. Limited human data support the conclusion that anticholinergic activity enhances AD-related neuropathology and neurodegeneration. However, experimental data from a tauopathy mouse model indicated anticholinergic activity might enhance neurodegeneration with enhanced neuroinflammation including microglial activation.

Hypothesis of Endogenous Anticholinergic Activity in Alzheimer's Disease.

In this article, we review and repropose our hypothesis of the endogenous appearance of anticholinergic activity (AA) in Alzheimer's disease (AD). First, we introduce our previous articles and speculate that, because acetylcholine (ACh) regulates both cognitive function and inflammation, downregulation of this neurotransmitter causes upregulation of the inflammatory system. AA then appears endogenously with the production of cytokines and the downregulation of ACh in AD. To support our hypothesis, we present a female AD patient whose AA was considered to occur endogenously through her AD pathology. Her serum anticholinergic activity (SAA) was positive at her first visit to our memory clinic, was negative at the 1-year and 2-year follow-up visits, and had become positive again by 3 years. We speculate that the initial positive SAA was related to her AD pathology plus mental stress, and that her SAA at 3 years was related to her AD pathology only. Consequently, we believe that 2 patterns of SAA positivity (and therefore AA) exist. One occurs when the downregulation of ACh reaches a critical level, and the other occurs with the addition of some other factor such as medication, induced illness or mental stress that causes AA to affect AD pathology. Finally, we consider the pharmacotherapy of AD based on the proposed hypothesis and conclude that cholinesterase inhibitors can be used to prevent rapid disease progression, whereas N-methyl-D-aspartate receptor antagonists should be reserved for the treatment of AD that is already in a stage of rapid progression. We also propose a staging schema for patients with AD.

Pharmacotherapy for Neurocognitive Disorders Based on the Hypothesis of Endogenous Appearance of Anticholinergic Activity.

We previously proposed the hypothesis of endogenous anticholinergic activity (AA) in Alzheimer's disease (AD). According to this hypothesis, the downregulation of acetylcholine seen in AD is associated with upregulation/hyperactivity of N-methyl-D-aspartate receptor (NMDAR). The hyperactivation of NMDAR then induces inflammation, which, in turn, causes AA to appear endogenously. Based on this hypothesis, we commented that cholinesterase inhibitors (ChEIs) are 'preventative' therapy for AD and NMDAR antagonists are the true 'treatment' for AD. We also noted that ChEIs, such as donepezil, could treat delirium. Moreover, we proposed measuring serum anticholinergic activity in patients, particularly AD patients, in out-of-hospital pharmacies to monitor the anticholinergic burden for targeted treatment.

A Review of the Role of Anticholinergic Activity in Lewy Body Disease and Delirium.

We have previously proposed a hypothesis in which we argue that anticholinergic activity (AA) appears endogenously in Alzheimer's disease (AD). Acetylcholine (ACh) controls both cognitive function and inflammation. Consequently, when the downregulation of ACh reaches critical levels, the inflammatory system is upregulated and proinflammatory cytokines with AA appear. However, factors other than downregulation of ACh can produce AA; even if ACh downregulation does not reach critical levels, AA can still appear if one of these other AA-producing factors is added. These factors can include neurocognitive disorders other than AD, such as delirium and Lewy body disease (LBD). In delirium, ACh downregulation fails to reach critical levels, but AA appears due to the use of medicines, physical illnesses or mental stress (termed 'AA inserts'). In LBD, we speculate that AA appears endogenously, even in the absence of severe cognitive dysfunction, for 2 reasons. One reason is that patterns of ACh deterioration are different in LBD from those in AD, with synergistic actions between amyloid and α-synuclein thought to cause additional or severe symptoms that accelerate the disease course. The second reason is that AA occurs through disinhibition by reduced cortisol levels that result from severe autonomic parasympathetic dysfunction in LBD.

Anticholinergic Activity and Schizophrenia.

In this article, we review the downregulation of acetylcholinergic activity in schizophrenia and discuss the similarity and difference between Alzheimer's disease (AD) and schizophrenia in terms of acetylcholine (ACh) and anticholinergic activity (AA); then, we propose the use of cognition-enhancing therapy for schizophrenia. As ACh regulates an inflammatory system, when the cholinergic system is downregulated to a critical level, the inflammatory system is activated. We consider the possibility that AA appears endogenously in AD and accelerates AD pathology. This hypothesis can also be applied to schizophrenia. In fact, even before the onset of the disorder, in the prodromal phase of schizophrenia, cognitive dysfunction exists, and antibodies against astrocyte muscarinic-1 and muscarinic-2 receptors are present in the serum of patients with the paranoid type of schizophrenia. Then we noted that the prodromal phase in schizophrenia might correspond to the mild stage in AD and the acute phase to moderate stage concerning AA. We also think that we should enhance cognition in schizophrenia even in the prodromal phase because as mentioned above, downregulation of ACh is prominent in schizophrenia even in the prodromal phase.

Demonstrating the Role of Anticholinergic Activity in a Mood Disorder.

We report a case of a 54-year-old woman presenting with amnesia, apathy, work-related difficulties and mental stress. At presentation, her Mini-Mental State Examination score was 27 and her serum anticholinergic activity (SAA) was positive without medication or recent physical illnesses. In addition, magnetic resonance imaging revealed mild atrophy of the frontal and temporal lobes, with a relatively intact hippocampus. Consequently, we diagnosed mild cognitive impairment due to Alzheimer's disease and prescribed a cholinesterase inhibitor (donepezil, 10 mg/day); her SAA fully disappeared and clinical symptoms partially resolved. Addition of duloxetine coupled with environmental adjustments caused her cognitive function to return to a normal level, so we diagnosed pseudodementia due to depression. In this case, we believe that the simultaneous cholinergic burden and mental stress led to positive SAA, which made it reasonable to prescribe a cholinesterase inhibitor to ameliorate the associated acetylcholine hypoactivity. We believe that it is essential to recognize the importance of prescribing a cholinesterase inhibitor for specific patients, even those with pseudodementia, to control their clinical symptoms. Moreover, SAA might be a useful biomarker for identifying this subgroup of patients. We propose that anticholinergic activity appears endogenously in mood disorders (depression and bipolar disorder) and set out our rationalization for this hypothesis.

Beyond the Hypothesis of Serum Anticholinergic Activity in Alzheimer's Disease: Acetylcholine Neuronal Activity Modulates Brain-Derived Neurotrophic Factor Production and Inflammation in the Brain.

The brain of Alzheimer's disease (AD) patients is characterized by neurodegeneration, especially an acetylcholine (ACh) neuronal deficit with accumulation of ß-amyloid protein, which leads to oxygen stress and inflammation. The active oxygen directly damages the neuron by increasing intracellular Ca(2+). The inflammation is due to activation of the microglia, thereby producing cytokines which inhibit the production of brain-derived neurotrophic factor (BDNF). As the BDNF acts by neuronal protection, synaptogenesis and neurogenesis, the reduction of BDNF in the brain of AD patients worsens the symptoms of AD. On the other hand, treatment of AD patients with a cholinesterase inhibitor enhances ACh activity and inhibits inflammation. Then the expression of BDNF is restored and neuroprotection reestablished. However, there are several reports which showed controversial results concerning the relationship between BDNF and AD. We speculate that BDNF is related to some neurocognitive process and reflects neuronal activity in other neurodegenerative and neuropsychiatric disorders and that in the mild cognitive impairment stage, BDNF and choline acetyltransferase (ChAT) activities are hyperactivated because of a compensatory mechanism of AD pathology. In contrast, in the mild stage of AD, BDNF and ChAT activity are downregulated.

Plasma Cholinesterase Activity in Alzheimer's Disease.

Cholinesterase inhibitors (ChEIs) are not allowed to be prescribed in combination, which means that we need to select 1 of 3 ChEIs for use in a patient with Alzheimer's disease (AD). However, there is no quantitative analysis on the differences between these agents. In this article, we propose that plasma cholinesterase activity (pChE) could be used as the standard for differentiating between rivastigmine (Riv) and donepezil (Don) in the management of AD. To date, we have treated 6 patients with Riv 18 mg and 5 patients with Don 5 mg. The pChE is related to low-grade inflammation associated with AD, diabetes mellitus and lipid metabolic dysfunction. Moreover, low pChE is related to liver dysfunction. The pChE must be kept under control. We speculated that Riv is the most appropriate therapy for patients with relatively high pChE, whereas Don is best reserved for those AD patients with relatively low pChE.

Assessment of Cognitive Dysfunction Caused by Anticholinergic Burden in Japanese Alzheimer's Disease Patients, Using the Most Commonly Used Scales in Japan.

Anticholinergic activity (AA) is generally thought to cause cognitive dysfunction, especially in Alzheimer's disease (AD), one of the neurocognitive disorders related to memory disturbances. Therefore, it is important to evaluate cognitive functions to determine whether they are associated with anticholinergic burden. In Japan, the most frequently used cognitive scale for evaluating cognitive functions is the revised version of Hasegawa's Dementia Rating Scale (HDS-R). However, the relationship between anticholinergic burden and cognitive functions has not been previously examined using the HDS-R. Therefore, here we used the HDS-R to evaluate the relationship between serum anticholinergic activity (SAA) and cognitive functions in 76 patients with AD, 26 of whom had positive SAA [SAA (+)] with a mean of 4.14 ± 2.70 nM. Total scores for orientations to time and place, registration, and recall were significantly lower in the SAA (+) group than in the SAA (-) group (P < 0.05), suggesting potential relationships between SAA and disorientations to time and place in current surroundings as well as memory disturbances. Thus, the disorientations to time and place might explain the clinical features of confusion in current surroundings caused by anticholinergic burden in AD.

Serum anticholinergic activity: a possible peripheral marker of the anticholinergic burden in the central nervous system in Alzheimer's disease.

We review the utility of serum anticholinergic activity (SAA) as a peripheral marker of anticholinergic activity (AA) in the central nervous system (CAA). We hypothesize that the compensatory mechanisms of the cholinergic system do not contribute to SAA if their system is intact and that if central cholinergic system deteriorates alone in conditions such as Alzheimer's disease or Lewy body dementia, CAA and SAA are caused by way of hyperactivity of inflammatory system and SAA is a marker of the anticholinergic burden in CNS. Taking into account the diurnal variations in the plasma levels of corticosteroids, which are thought to affect SAA, it should be measured at noon or just afterward.