Immunological assay using a solid-state pore with a low limit of detection.

Emerging infectious diseases, cancer, and other diseases are quickly tested mainly via immune reactions based on specific molecular recognition between antigens and antibodies. By changing the diameter of solid-state pores, biomolecules of various sizes can be rapidly detected at the single-molecule level. The combination of immunoreactions and solid-state pores paves the way for an efficient testing method with high specificity and sensitivity. The challenge in developing this method is achieving quantitative analysis using solid-state pores. Here, we demonstrate a method with a low limit of detection for testing tumor markers using a combination of immunoreactions and solid-state pore technology. Quantitative analysis of the mixing ratio of two and three beads with different diameters was achieved with an error rate of up to 4.7%. The hybrid solid-state pore and immunoreaction methods with prostate-specific antigen (PSA) and anti-PSA antibody-modified beads achieved a detection limit of 24.9 fM PSA in 30 min. The hybrid solid-state pore and immunoreaction enabled the rapid development of easy-to-use tests with lower limit of detection and greater throughput than commercially available immunoassay for point-of-care testing.

Using novel micropore technology combined with artificial intelligence to differentiate Staphylococcus aureus and Staphylococcus epidermidis.

Methods for identifying bacterial pathogens are broadly categorised into conventional culture-based microbiology, nucleic acid-based tests, and mass spectrometry. The conventional method requires several days to isolate and identify bacteria. Nucleic acid-based tests and mass spectrometry are relatively rapid and reliable, but they require trained technicians. Moreover, mass spectrometry requires expensive equipment. The development of a novel, inexpensive, and simple technique for identifying bacterial pathogens is needed. Through combining micropore technology and assembly machine learning, we developed a novel classifier whose receiver operating characteristic (ROC) curve showed an area under the ROC curve of 0.94, which rapidly differentiated between Staphylococcus aureus and Staphylococcus epidermidis in this proof-of-concept study. Morphologically similar bacteria belonging to an identical genus can be distinguished using our method, which requires no specific training, and may facilitate the diagnosis and treatment of patients with bacterial infections in remote areas and in developing countries.

High-precision rapid testing of omicron SARS-CoV-2 variants in clinical samples using AI-nanopore.

A digital platform that can rapidly and accurately diagnose pathogenic viral variants, including SARS-CoV-2, will minimize pandemics, public anxiety, and economic losses. We recently reported an artificial intelligence (AI)-nanopore platform that enables testing for Wuhan SARS-CoV-2 with high sensitivity and specificity within five minutes. However, which parts of the virus are recognized by the platform are unknown. Similarly, whether the platform can detect SARS-CoV-2 variants or the presence of the virus in clinical samples needs further study. Here, we demonstrated the platform can distinguish SARS-CoV-2 variants. Further, it identified mutated Wuhan SARS-CoV-2 expressing spike proteins of the delta and omicron variants, indicating it discriminates spike proteins. Finally, we used the platform to identify omicron variants with a sensitivity and specificity of 100% and 94%, respectively, in saliva specimens from COVID-19 patients. Thus, our results demonstrate the AI-nanopore platform is an effective diagnostic tool for SARS-CoV-2 variants.

Lung Adenocarcinoma with Chronic Lymphocytic Leukemia Mimicking Bone Metastasis.

A 77-year-old man was referred to our hospital for abnormal thoracic radiographs. Computed tomography (CT) revealed a 20-mm subpleural ground-glass opacity in the right S6 area. A CT-guided biopsy revealed lung adenocarcinoma. Fluorodeoxyglucose-positron emission tomography revealed multiple abnormal bone accumulations, and a subsequent biopsy of a left iliac bone lesion revealed chronic lymphocytic leukemia. A right lower lung lobectomy was performed for the lung adenocarcinoma (cT1bN0M0, stage IA2). An aggressive biopsy of the bone lesion confirmed a rare case of double primary malignancies, which determined the patient's treatment and outcomes.

Methodology to Detect Biological Particles Using a Biosensing Surface Integrated in Resistive Pulse Sensing.

Resistive pulse sensing (RPS) is an analytical method that can be used to individually count particles from a small sample. RPS simply monitors the physical characteristics of particles, such as size, shape, and charge density, and the integration of RPS with biosensing is an attractive theme to detect biological particles such as virus and bacteria. In this report, a methodology of biosensing on RPS was investigated. Polydopamine (PD), an adhesive component of mussels, was used as the base material to create a sensing surface. PD adheres to most materials, such as noble metals, metal oxides, semiconductors, and polymers; as a result, PD is a versatile intermediate layer for the fabrication of a biosensing surface. As an example of a biological particle, human influenza A virus (H1N1 subtype) was used to monitor translocation of particles through the pore membrane. When virus-specific ligands (6'-sialyllactose) were immobilized on the pore surface, the translocation time of the virus particles was considerably extended. The detailed translocation data suggest that the viral particles were trapped on the sensing surface by specific interactions. In addition, virus translocation processes on different pore surfaces were distinguished using machine learning. The result shows that the simple and versatile PD-based biosensor surface design was effective. This advanced RPS measurement system could be a promising analytical technique.

Combining machine learning and nanopore construction creates an artificial intelligence nanopore for coronavirus detection.

High-throughput, high-accuracy detection of emerging viruses allows for the control of disease outbreaks. Currently, reverse transcription-polymerase chain reaction (RT-PCR) is currently the most-widely used technology to diagnose the presence of SARS-CoV-2. However, RT-PCR requires the extraction of viral RNA from clinical specimens to obtain high sensitivity. Here, we report a method for detecting novel coronaviruses with high sensitivity by using nanopores together with artificial intelligence, a relatively simple procedure that does not require RNA extraction. Our final platform, which we call the artificially intelligent nanopore, consists of machine learning software on a server, a portable high-speed and high-precision current measuring instrument, and scalable, cost-effective semiconducting nanopore modules. We show that artificially intelligent nanopores are successful in accurately identifying four types of coronaviruses similar in size, HCoV-229E, SARS-CoV, MERS-CoV, and SARS-CoV-2. Detection of SARS-CoV-2 in saliva specimen is achieved with a sensitivity of 90% and specificity of 96% with a 5-minute measurement.

Hypoglycemic attacks and growth failure are the most common manifestations of citrin deficiency after 1 year of age.

Citrin deficiency develops in different symptomatic periods from the neonatal period to adulthood. Some infantile patients are diagnosed by newborn mass screening or symptoms of neonatal intrahepatic cholestasis caused by citrin deficiency, some patients in childhood may develop hepatopathy or dyslipidemia as failure to thrive and dyslipidemia caused by citrin deficiency, and some adults are diagnosed after developing adult-onset type 2 citrullinemia (CTLN2) with hyperammonemia or encephalopathy. A diagnosis is needed before the development of severe phenotypic CTLN2 but is often difficult to obtain because newborn mass screening cannot detect all patients with citrin deficiency, and undiagnosed patients often appear healthy in childhood. There are only a few reports that have described patients in childhood. To explore the clinical features of undiagnosed patients with citrin deficiency in childhood, we studied 20 patients who were diagnosed after the first year of life. Of these patients, 45% experienced hypoglycemic attacks in childhood. The acetoacetic acid level during hypoglycemic attacks was lower than expected. Growth failure at diagnosis (45%) was also noted. From the patients' history, fat- and protein-rich food preferences (80%), a low birth weight (70%), and prolonged jaundice or infantile hepatopathy (40%) were identified. To diagnose citrin deficiency in childhood, we should ask about food preferences and a history of infantile hepatopathy for all children with severe hypoglycemia or growth failure and consider the genetic test for citrin deficiency if the patient has characteristic food preferences or a history of infantile hepatopathy.

Mortality in rheumatoid arthritis patients with pulmonary nontuberculous mycobacterial disease: A retrospective cohort study.

OBJECTIVE: The aim of this study was to compare long-term mortality following diagnosis of pulmonary nontuberculous mycobacterial (NTM) disease between patients with and without rheumatoid arthritis (RA) and to evaluate predictive factors for death outcomes. METHODS: We reviewed the electronic medical records of all patients who were newly diagnosed with pulmonary NTM disease at participating institutions between August 2009 and December 2018. Patients were followed until death, loss to follow-up, or the end of the study. Taking into consideration the presence of competing risks, we used the cumulative incidence function with Gray's test and Fine-Gray regression analysis for survival analysis. RESULTS: A total of 225 patients (34 RA patients and 191 non-RA controls) were followed, with a mean time of 47.5 months. Death occurred in 35.3% of RA patients and 25.7% of non-RA patients. An exacerbation of pulmonary NTM disease represented the major cause of death. The estimated cumulative incidence of all-cause death at 5 years was 24% for RA patients and 23% for non-RA patients. For NTM-related death, the 5-year cumulative incidence rate was estimated to be 11% for RA patients and 18% for non-RA patients. Gray's test revealed that long-term mortality estimates were not significantly different between patient groups. Fine-Gray regression analysis showed that the predictive factors for NTM-related death were advanced age (adjusted hazards ratio 7.28 [95% confidence interval 2.91-18.20] for ≥80 years and 3.68 [1.46-9.26] for 70-80 years vs. <70 years), male sex (2.40 [1.29-4.45]), Mycobacterium abscessus complex (4.30 [1.46-12.69] vs. M. avium), and cavitary disease (4.08 [1.70-9.80]). CONCLUSIONS: RA patients with pulmonary NTM disease were not at greater risk of long-term mortality compared with non-RA patients. Rather, advanced age, male sex, causative NTM species, and cavitary NTM disease should be considered when predicting the outcomes of RA patients with pulmonary NTM disease.

Hypoketotic hypoglycemia in citrin deficiency: a case report.

BACKGROUND: Citrin deficiency (CD) is a recessive metabolic disease caused by biallelic pathogenic variants in SLC25A13. Although previous studies have reported ketosis in CD, it was observed at the time of euglycemia or mild hypoglycemia. Blood ketone levels concomitant with symptomatic or severe hypoglycemia in CD have not been a topic of focus despite its importance in identifying the etiology of hypoglycemia and assessing the ability of fatty acid utilization. Herein, we describe a patient with CD who had repeated episodes of hypoglycemia with insufficient ketosis. CASE PRESENTATION: A 1-year-old boy with repetitive hypoglycemia was referred to us to investigate its etiology. The fasting load for 13 h led to hypoketotic hypoglycemia, indicating the possibility of partial ß-oxidation dysfunction. A genetic test led to the diagnosis of CD. The hypoglycemic episodes disappeared after switching to a medium-chain triglyceride-containing formula. CONCLUSIONS: This case report suggests that symptomatic or severe hypoglycemia in patients with CD could be associated with relatively low levels of ketone bodies, implying that ß-oxidation in these patients might possibly be partially disrupted. When encountering a patient with hypoglycemia, clinicians should check blood ketone levels and bear in mind the possibility of CD because excessive intravenous administration of glucose can cause decompensated symptoms in patients with CD as opposed to other disorders presenting with hypoketotic hypoglycemia, such as fatty acid oxidation disorders. Further studies in a large-scale cohort are warranted to confirm our speculation.

Correction: Biallelic GALM pathogenic variants cause a novel type of galactosemia.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Current treatment for citrin deficiency during NICCD and adaptation/compensation stages: Strategy to prevent CTLN2.

Identification of the genes responsible for adult-onset type II citrullinemia (CTLN2) and citrin protein function have enhanced our understanding of citrin deficiency. Citrin deficiency is characterized by 1) neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD); 2) adaptation/compensation stage with unique food preference from childhood to adulthood; and 3) CTLN2. The treatment of NICCD aims to prevent the progression of cholestasis, and it includes medium chain triglycerides (MCT) milk and lactose-free milk, in addition to medications (e.g., vitamin K2, lipid-soluble vitamins and ursodeoxycholic acid). Spontaneous remission around the age of one is common in NICCD, though prolonged cholestasis can lead to irreversible liver failure and may require liver transplantation. The adaptation/compensation stage (after one year of age) is characterized by the various signs and symptoms such as hypoglycemia, fatty liver, easy fatigability, weight loss, and neuropsychiatric symptoms. Some poorly-controlled patients show failure to thrive and dyslipidemia caused by citrin deficiency (FTTDCD). Diet therapy is the key in the adaptation/compensation stage. Protein- and fat-rich diet with a protein: fat: carbohydrate ratio being 15-25%: 40-50%: 30-40% along with the appropriate energy intake is recommended. The use of MCT oil and sodium pyruvate is also effective. The toxicity of carbohydrate is well known in the progression to CTLN2 if the consumption is over a long term or intense. Alcohol can also trigger CTLN2. Continuous intravenous hyperalimentation with high glucose concentration needs to be avoided. Administration of Glyceol® (an osmotic agent containing glycerol and fructose) is contraindicated. Because the intense treatment such as liver transplantation may become necessary to cure CTLN2, the effective preventative treatment during the adaptation/compensation stage is very important. At present, there is no report of a case with patients reported having the onset of CTLN2 who are on the diet therapy and under the appropriate medical support during the adaptation/compensation stage.

The prevalence of GALM mutations that cause galactosemia: A database of functionally evaluated variants.

Galactosemia is a metabolic disorder that affects the appropriate metabolism of ß-D-galactose. Deficiencies in three of the enzymes of the Leloir pathway, namely, GALT, GALK1, or GALE, are characterized as type I, II, and III galactosemia, respectively. Recently, we reported a novel type of galactosemia (type IV galactosemia) due to biallelic GALM mutations. Genetic diagnosis is indispensable for diagnosing GALM deficiency because no biochemical diagnosis method has been established. Given that apparently pathogenic variants in GALM are found in public variant databases, we presumed the presence of pathogenic variants that have not been reported. In this study, we explore 67 GALM variants that are prevalent in the ExAC database, including 57 missense variants, 7 stop-gain variants, 2 frameshift variants, and 1 splice-site variant. We performed an in vitro expression assay and an enzyme activity assay. Among the 66 variants except for 1 splice-site variant, 29 produced no or faint protein expression and were judged as pathogenic variants. Furthermore, the remaining 37 variants were evaluated by enzyme activity assay. Two showed mildly reduced enzyme activity and were classified as benign. Based on our study, the estimated incidence of GALM deficiency is 1:228,411 in all populations, 1:10,388 in the African population, and 1:80,747 in the Japanese population. Our GALM mutation database is useful for the genetic diagnosis of GALM deficiency.

Biallelic GALM pathogenic variants cause a novel type of galactosemia.

PURPOSE: Galactosemia is caused by metabolic disturbances at various stages of galactose metabolism, including deficiencies in enzymes involved in the Leloir pathway (GALT, GALK1, and GALE). Nevertheless, the etiology of galactosemia has not been identified in a subset of patients. This study aimed to explore the causes of unexplained galactosemia. METHODS: Trio-based exome sequencing and/or Sanger sequencing was performed in eight patients with unexplained congenital galactosemia. In vitro enzymatic assays and immunoblot assays were performed to confirm the pathogenicity of the variants. RESULTS: The highest blood galactose levels observed in each patient were 17.3-41.9 mg/dl. Bilateral cataracts were observed in two patients. In all eight patients, we identified biallelic variants (p.Arg82*, p.Ile99Leufs*46, p.Gly142Arg, p.Arg267Gly, and p.Trp311*) in the GALM encoding galactose mutarotase, which catalyzes epimerization between ß- and α-D-galactose in the first step of the Leloir pathway. GALM enzyme activities were undetectable in lymphoblastoid cell lines established from two patients. Immunoblot analysis showed the absence of the GALM protein in the patients' peripheral blood mononuclear cells. In vitro GALM expression and protein stability assays revealed altered stabilities of the variant GALM proteins. CONCLUSION: Biallelic GALM pathogenic variants cause galactosemia, suggesting the existence of type IV galactosemia.

A male case with CDKL5-associated encephalopathy manifesting transient methylmalonic acidemia.

Mutations in the X-linked gene CDKL5 cause early-onset epileptic encephalopathy and severe developmental delay. Because this disorder predominantly affects females, the full clinical spectrum of male patients remains elusive. We herein report a 16-year-old boy, who suffered from intractable seizures 20 days after birth. Serial electroencephalograms detected recurrent focal epileptiform discharges from age 4 months, which evolved to hypsarrhythmia later in infancy. Mass-spectrometric analyses revealed increase in urinary excretion of methylmalonic acid without perturbed concentrations of propionic acid, homocystein and methionine. Whole-exome sequencing identified a de novo, truncating mutation in CDKL5 (NM_003159.2:c.419dupA, p.Asn140Lysfs*8). Targeted sequencing excluded concomitant mutations in methylmalonic academia-associated genes. No methylmalonic acidemia has been reported in children with CDKL5 disorder. Extensive analyses on organic acid metabolism for males with CDKL5 mutations will gain more insight into their biochemical profiles in infancy.

Central Venous Catheter-Related Bloodstream Infection with Kocuria kristinae in a Patient with Propionic Acidemia.

Kocuria kristinae is a catalase-positive, coagulase-negative, Gram-positive coccus found in the environment and in normal skin and mucosa in humans; however, it is rarely isolated from clinical specimens and is considered a nonpathogenic bacterium. We describe a case of catheter-related bacteremia due to K. kristinae in a young adult with propionic acidemia undergoing periodic hemodialysis. The patient had a central venous catheter implanted for total parenteral nutrition approximately 6 months prior to the onset of symptoms because of repeated acute pancreatitis. K. kristinae was isolated from two sets of blood cultures collected from the catheter. Vancomycin followed by cefazolin for 16 days and 5-day ethanol lock therapy successfully eradicated the K. kristinae bacteremia. Although human infections with this organism appear to be rare and are sometimes considered to result from contamination, physicians should not underestimate its significance when it is isolated in clinical specimens.

Reversible brain atrophy in glutaric aciduria type 1.

Glutaric aciduria type 1 (GA1) is a rare metabolic disorder caused by a deficiency of glutaryl-CoA dehydrogenase. The typical clinical onset features an acute encephalopathic crisis developed in early childhood, causing irreversible striatal injury. Recently, tandem mass spectrometry of spots of dried blood has allowed pre-symptomatic detection of GA1 in newborns. Early treatment can prevent irreversible neurological injury. We report the case of a girl with GA1 who exhibited a characteristic reversible change upon brain magnetic resonance imaging (MRI). She was diagnosed with GA1 as a newborn. She commenced dietary carnitine and her intake of lysine and tryptophan were reduced at the age of 4weeks. After treatment commenced, her mean glutarylcarnitine level was lower than that in the previous reports. The plasma lysine and tryptophan levels were maintained below the normal ranges. At 4months, brain MRI revealed a widened operculum with dilatation of the subarachnoid spaces surrounding the atrophic bilateral frontotemporal lobes; this is typical of GA1 patients. However, at 17months, MRI revealed that the atrophic lesion had disappeared and she subsequently underwent normal maturation. She has never suffered a metabolic decompensation episode. At 26months, her development and brain MRI were normal. The present reversible brain atrophy in a patient with GA1 indicates that early dietary modifications with a lower level of glutarylcarnitine and administration of carnitine can lead to normal development.

Isovaleric acidemia: Therapeutic response to supplementation with glycine, l-carnitine, or both in combination and a 10-year follow-up case study.

Isovaleric acidemia (IVA) is an organic acid disease caused by a deficiency of isovaleryl-CoA dehydrogenase. Deficiency of this enzyme leads to accumulation of organic acids, such as isovalerylcarnitine and isovalerylglycine. The proposed IVA treatments include leucine restriction and l-carnitine and/or glycine supplementation, which convert isovaleric acid into non-toxic isovalerylcarnitine and isovalerylglycine, respectively. We examined the therapeutic response using the leucine load test and performed a 10-year follow-up in the patient. METHODS: We evaluated the patient with IVA beginning at 5 years of age, when he presented with a mild to intermediate metabolic phenotype. Ammonia, free carnitine, isovalerylcarnitine, and isovalerylglycine were analyzed in the urine and blood after a meal consisting of 1600 mg leucine with glycine alone (250 mg/kg/day), l-carnitine alone (100 mg/kg/day), or both glycine and l-carnitine for four days each. RESULTS: (Leucine load test) Three hours after the meal, serum ammonia levels increased most dramatically with glycine treatment alone, then with both in combination, and least with l-carnitine alone. Urinary isovalerylglycine levels increased 2-fold more with glycine supplementation than those following supplementation with both agents or with l-carnitine alone. Treatment with both agents resulted in a gradual increase in urinary acylcarnitine levels during the 6-h period following the leucine load, reaching concentrations comparable to those observed with l-carnitine alone. (Clinical course) After initiation of both glycine (200 mg/kg/day) and l-carnitine (100 mg/kg/day) supplementation at 5 years of age, doses were gradually reduced to 111.7 mg/kg/day and 55.8 mg/kg/day, respectively, at 15 years of age. His mind and body had developed without any sequelae. DISCUSSION: We concluded that l-carnitine conjugated isovaleric acid earlier than glycine. Additionally, during the 10-year follow-up period, the patient displayed no clinical deterioration.