Biochemical Heterogeneity Research Articles

Advances in microfluidic platforms for tumor cell phenotyping: from bench to bedside.

Heterogeneities among tumor cells significantly contribute towards cancer progression and therapeutic inefficiency. Hence, understanding the nature of cancer through liquid biopsies and isolation of circulating tumor cells (CTCs) has gained considerable interest over the years. Microfluidics has emerged as one of the most popular platforms for performing liquid biopsy applications. Various label-free and labeling techniques using microfluidic platforms have been developed, the majority of which focus on CTC isolation from normal blood cells. However, sorting and profiling of various cell phenotypes present amongst those CTCs is equally important for prognostics and development of personalized therapies. In this review, firstly, we discuss the biophysical and biochemical heterogeneities associated with tumor cells and CTCs which contribute to cancer progression. Moreover, we discuss the recently developed microfluidic platforms for sorting and profiling of tumor cells and CTCs. These techniques are broadly classified into biophysical and biochemical phenotyping methods. Biophysical methods are further classified into mechanical and electrical phenotyping. While biochemical techniques have been categorized into surface antigen expressions, metabolism, and chemotaxis-based phenotyping methods. We also shed light on clinical studies performed with these platforms over the years and conclude with an outlook for the future development in this field.

Clinic, etiology and pathogenesis of comorbid conditions in children with hyperkinetic disorder

Hyperkinetic disorder (HD) refers to chronic non-processual diseases, including among the main symptoms impaired attention, impulsivity and hyperactivity, and corresponds to a mixed version of attention deficit hyperactivity disorder (ADHD).Currently, the etiology of HD is considered as a polyetiological concept, since the formation of any chronic disorder involves, first of all, biological factors, including hereditary mechanisms, nonspecific “trigger” factors and factors of early brain damage that “support” the course of the diseaseand ensuring the uniqueness of each clinical case.The cause of HD is a genetically determined pathogenetic mechanism realized by the dysfunction of monoamine systems, in most cases complicated by minimal residual organic lesions of the central nervous system. In this case, a close connection is established between the clinical manifestations of the disorder in question and the biochemical imbalance of monoamine systems, creating a picture of the clinical and biochemical heterogeneity of the main symptoms of a hyperkinetic disorder. Hyperkinetic disorder is characterized by both clinical and biochemical heterogeneity and is determined by a number of etiological factors that create a variety of manifestations not only of the disease itself, but also of its comorbid conditions, which largely determines the direction of rehabilitation measures. Under these conditions, the specific weight of each factor at different stages of the disease depends on a number of exogenous situations.It is logical in this light, according to the current prevailing view, that GH symptoms are viewed as multidimensional traits due to the concerted action of many common and rare genetic variants in interaction with multiple environmental factors.

Hyperornithinemia-Hyperammonemia-Homocitrullinuria Syndrome in Vietnamese Patients.

Background and Objectives: Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome (HHH; OMIM 238970) is one of the rare urea cycle disorders. Ornithine carrier 1 deficiency causes HHH syndrome, characterized by failure of mitochondrial ornithine uptake, hyperammonemia, and accumulation of ornithine and lysine in the cytoplasm. The initial presentation and time of diagnosis in HHH highly varies. Genetic analysis is critical for diagnosis. Materials and Methods: This study encompassed retrospective and prospective analyses of four unrelated Vietnamese children diagnosed with HHH syndrome. Results: The age of diagnosis ranged from 10 days to 46 months. All four cases demonstrated hyperornithinemia and prolonged prothrombin time. Three out of four cases presented with hyperammonemia, elevated transaminases, and uraciluria. No homocitrulline was detected in the urine. Only one case depicted oroticaciduria. Genetic analyses revealed three pathogenic variants in the SLC25A15 gene, with the c.535C>T (p.Arg179*) variant common in Vietnamese patients. The c.562_564del (p.Phe188del) and c.408del (p.Met137Cysfs*10) variants were detected in one case. The latter variant has yet to be reported in the literature on HHH patients. After intervention with a protein-restricted diet, ammonia-reducing therapy, and L-carnitine supplementation, hyperammonemia was not observed, and liver enzyme levels returned to normal. Conclusions: Our results highlighted the clinical and biochemical heterogeneity of HHH syndrome and posed that HHH syndrome should be considered when individuals have hyperammonemia, elevated transaminase, and decreased prothrombin time.

Adipose-derived mesenchymal stem cells' adipogenesis chemistry analyzed by FTIR and Raman metrics

The full understanding of molecular mechanisms of cell differentiation requires a holistic view. Here we combine label-free FTIR and Raman hyperspectral imaging with data mining to detect the molecular cell composition enabling noninvasive monitoring of cell differentiation and identifying biochemical heterogeneity. Mouse adipose-derived mesenchymal stem cells (AD-MSCs) undergoing adipogenesis were followed by Raman and FT-IR imaging, Oil Red, and immunofluorescence. A workflow of the data analysis (IRRSmetrics4stem) was designed to identify spectral predictors of adipogenesis and test machine-learning (ML) methods (hierarchical clustering, PCA, PLSR) for the control of the AD-MSCs differentiation degree. IRRSmetrics4stem provided insights into the chemism of adipogenesis. With single-cell tracking, we established IRRS metrics for lipids, proteins, and DNA variations during AD-MSCs differentiation. The over 90% predictive efficiency of the selected ML methods proved the high sensitivity of the IRRS metrics. Importantly, the IRRS metrics unequivocally recognize a switch from proliferation to differentiation. This study introduced a new bioassay identifying molecular markers indicating molecular transformations and delivering rapid and machine learning-based monitoring of adipogenesis that can be relevant to other differentiation processes. Thus, we introduce a novel, rapid, machine learning-based bioassay to identify molecular markers of adipogenesis. It can be relevant to identification of differentiation-related molecular processes in other cell types, and beyond the cell differentiation including progression of different cellular pathophysiologies reconstituted in vitro.

High Prevalence of Familial Hypercholesterolemia Due to the Founder Effect of the LDLR c.2271del Variant in Communities of Oaxaca, Mexico

In Mexico, familial hypercholesterolemia (FH) is underdiagnosed, but population screening in small communities where at least one homozygous patient has already been detected results in a useful and inexpensive approach to reduce this problem. Considering that we previously reported nine homozygous cases from the state of Oaxaca, we decided to perform a population screening to identify patients with FH and to describe both their biochemical and genetic characteristics. LDL cholesterol (LDLc) was quantified in 2,093 individuals from 11 communities in Oaxaca; either adults with LDLc levels ≥170 mg/dL or children with LDLc ≥130 mg/dL were classified as suggestive of FH and therefore included in the genetic study. LDLR and APOB (547bp fragment of exon 26) genes were screened by sequencing and MLPA analysis. Two hundred and five individuals had suggestive FH, with a mean LDLc of 223 ± 54 mg/dL (range: 131-383 mg/dL). Two pathogenic variants in the LDLR gene were detected in 149 individuals: c.-139_-130del (n = 1) and c.2271del (n = 148). All patients had a heterozygous genotype. With the cascade screening of their relatives (n = 177), 15 heterozygous individuals for the c.2271del variant were identified, presenting a mean LDLc of 133 ± 35 mg/dL (range: 60-168 mg/dL). The FH frequency in this study was 7.8% (164/2093), the highest reported worldwide. A founder effect combined with inbreeding could be responsible for the high percentage of patients with the LDLR c.2271del variant (99.4%), which allowed us to detect both significant biochemical heterogeneity and incomplete penetrance; hence, we assumed the presence of phenotype-modifying variants.

New resolution independent approach to noise estimation in Minimum Noise Fraction denoising of tissues measured with Infrared Imaging

The Minimum Noise Fraction (MNF) was originally developed for remote sensing data denoising. However, due to the hyperspectral character of Infrared (IR) imaging data, MNF is becoming increasingly popular in this field. IR imaging obtains data rich in biochemical information, therefore, it is extensively applied in tissue analysis and classification. It is popular to use different IR objectives of different magnification, which combined with Focal Plane Array (FPA) detector of fixed pixels size, give varying projected pixel sizes and as a result – different spatial resolutions. The MNF method proposed by Green et al. uses a noise correlation matrix that is calculated based on neighboring pixel difference, which heavily depends on the registered image magnification and thus spatial resolution, leading to different denoising efficiencies and signal loss. Here, we presented a new resolution-independent approach to noise matrix estimation (MNF2) based on the 2 sequential scans of the sample. In this way, the data acquisition step is only minimally changed, while offering a uniform denoising step. We decided to test our method on representative breast tissue biopsy, due to its spatial and biochemical heterogeneity. We compared the performance of the new method for data measured using objectives giving different spatial pixel projections: low - 11.4 μm (3.5x), standard - 2.7 μm (15x), and high - 1.1 μm (36x). Results of this study show that conventional MNF for standard and low resolutions produces an altered denoised signal, while MNF2 gives a denoised signal of very good quality. In the case of high resolution data, standard MNF gives reasonable results, likewise proposed MNF2.

Microfluidic reactor designed for time-lapsed imaging of pretreatment and enzymatic hydrolysis of lignocellulosic biomass

The effect of tissue-specific biochemical heterogeneities of lignocellulosic biomass on biomass deconstruction is best understood through confocal laser scanning microscopy (CLSM) combined with immunohistochemistry. However, this process can be challenging, given the fragility of plant materials, and is generally not able to observe changes in the same section of biomass during both pretreatment and enzymatic hydrolysis. To overcome this challenge, a custom polydimethylsiloxane (PDMS) microfluidic imaging reactor was constructed using standard photolithographic techniques. As proof of concept, CLSM was performed on 60 μm-thick corn stem sections during pretreatment and enzymatic hydrolysis using the imaging reactor. Based on the fluorescence images, the less lignified parenchyma cell walls were more susceptible to pretreatment than the lignin-rich vascular bundles. During enzymatic hydrolysis, the highly lignified protoxylem cell wall was the most resistant, remaining unhydrolyzed even after 48 h. Therefore, imaging thin whole biomass sections was useful to obtain tissue-specific changes during biomass deconstruction.

FTIR microspectroscopy and multivariate analysis facilitate identification of dynamic changes in epithelial-to-mesenchymal transition induced by TGF-β in prostate cancer cells.

The standard diagnosis of prostate cancer is accomplished by the identification of cytomorphological deviations in biopsied tissues while immunohistochemistry is used to resolve the equivocal cases. Accumulating evidence favors the concept that epithelial-to-mesenchymal transition (EMT) is a stochastic process composed of multiple intermediate states instead of a single binary switch. Despite its significant role in promoting cancer aggressiveness, the current tissue-based risk stratification tools do not include any of the EMT phenotypes as a metric. As a proof-of-concept, the present study analyzes the temporal progression of EMT in transforming growth factor-beta (TGF-β) treated PC3 cells encompassing multifarious characteristics such as morphology, migration and invasion, gene expression, biochemical fingerprint, and metabolic activity. Our multimodal approach reinstates EMT plasticity in TGF-β treated PC3 cells. Further, it highlights that mesenchymal transition is accompanied by discernible changes in cellular morphometry and molecular signatures particularly in the range of 1800-1600 cm-1 and 3100-2800 cm-1 of Fourier-transformed infrared (FTIR) spectra signifying Amide III and lipid, respectively. Investigation of attenuated total reflectance (ATR)-FTIR spectra of extracted lipids from PC3 cell populations undergoing EMT identifies changes in stretching vibration at FTIR peaks at 2852, 2870, 2920, 2931, 2954, and 3010 cm-1 characteristics of fatty acids and cholesterol. Chemometric analysis of these spectra indicates that the level of unsaturation and acyl chain length of fatty acid coregister with differential epithelial/mesenchymal states of TGF-β treated PC3 cells. Observed changes in lipids also correlate with cellular nicotinamide adenine dinucleotide hydrogen (NADH) and flavin adenine dinucleotide dihydrogen (FADH2) levels and mitochondrial oxygen consumption rate. In summary, our study establishes that morphological and phenotypic traits of epithelial/mesenchymal variants of PC3 cells concur with their respective biochemical and metabolic properties. It also underscores that spectroscopic histopathology has a definitive potential to refine the diagnosis of prostate cancer reckoning its molecular and biochemical heterogeneities.

Imaging the metabolic reprograming of fatty acid synthesis pathway enables new diagnostic and therapeutic opportunity for breast cancer

BackgroundReprogrammed metabolic network is a key hallmark of cancer. Profiling cancer metabolic alterations with spatial signatures not only provides clues for understanding cancer biochemical heterogeneity, but also helps to decipher the possible roles of metabolic reprogramming in cancer development.MethodsMatrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) technique was used to characterize the expressions of fatty acids in breast cancer tissues. Specific immunofluorescence staining was further carried out to investigate the expressions of fatty acid synthesis-related enzymes.ResultsThe distributions of 23 fatty acids in breast cancer tissues have been mapped, and the levels of most fatty acids in cancer tissues are significantly higher than those in adjacent normal tissues. Two metabolic enzymes, fatty acid synthase (FASN) and acetyl CoA carboxylase (ACC), which being involved in the de novo synthesis of fatty acid were found to be up-regulated in breast cancer. Targeting the up-regulation of FASN and ACC is an effective approach to limiting the growth, proliferation, and metastasis of breast cancer cells.ConclusionsThese spatially resolved findings enhance our understanding of cancer metabolic reprogramming and give an insight into the exploration of metabolic vulnerabilities for better cancer treatment.

Role of heterogeneity in dictating tumorigenesis in epithelial tissues

AbstractBiological systems across various length and time scales are noisy, including tissues. Why are biological tissues inherently chaotic? Does heterogeneity play a role in determining the physiology and pathology of tissues? How do physical and biochemical heterogeneity crosstalk to dictate tissue function? In this review, we begin with a brief primer on heterogeneity in biological tissues. Then, we take examples from recent literature indicating functional relevance of biochemical and physical heterogeneity and discuss the impact of heterogeneity on tissue function and pathology. We take specific examples from studies on epithelial tissues to discuss the potential role of inherent tissue heterogeneity in tumorigenesis.

Chapter 4 - Leigh syndrome

Leigh syndrome, or subacute necrotizing encephalomyelopathy, was initially recognized as a neuropathological entity in 1951. Bilateral symmetrical lesions, typically extending from the basal ganglia and thalamus through brainstem structures to the posterior columns of the spinal cord, are characterized microscopically by capillary proliferation, gliosis, severe neuronal loss, and relative preservation of astrocytes. Leigh syndrome is a pan-ethnic disorder usually with onset in infancy or early childhood, but late-onset forms occur, including in adult life. Over the last six decades it has emerged that this complex neurodegenerative disorder encompasses more than 100 separate monogenic disorders associated with enormous clinical and biochemical heterogeneity. This chapter discusses clinical, biochemical and neuropathological aspects of the disorder, and postulated pathomechanisms. Known genetic causes, including defects of 16 mitochondrial DNA (mtDNA) genes and approaching 100 nuclear genes, are categorized into disorders of subunits and assembly factors of the five oxidative phosphorylation enzymes, disorders of pyruvate metabolism and vitamin and cofactor transport and metabolism, disorders of mtDNA maintenance, and defects of mitochondrial gene expression, protein quality control, lipid remodeling, dynamics, and toxicity. An approach to diagnosis is presented, together with known treatable causes and an overview of current supportive management options and emerging therapies on the horizon.

Familial hypocalciuric hypercalcaemia type 1 caused by a novel heterozygous missense variant in the CaSR gene, p(His41Arg): two case reports

BackgroundFamilial hypocalciuric hypercalcaemia (FHH) is a rare, inherited disorder of extracellular calcium sensing. It is clinically characterised by mild to moderate parathyroid hormone dependent hypercalcaemia, an autosomal dominant pattern of inheritance, and a normal to reduced urinary calcium excretion in spite of high serum calcium.Case presentationWe report two cases of FHH in a family caused by a novel pathogenic missense variant in the CaSR gene, p. His41Arg. Case 1, describes a 17 year old female with no significant past medical history, admitted with acute appendicitis requiring laparoscopic appendectomy and reporting a six month history of polydipsia. Routine investigations were significant for hypercalcaemia, corrected calcium 3.19 mmol/L (2.21-2.52mmol/L), elevated parathyroid hormone of 84pg/ml (15-65pg/ml) and a low 24-hour urine calcium of 0.75mmol/24 (2.50-7.50mmol/24). She was initially managed with intravenous fluids and Zolendronic acid with temporary normalisation of calcium though ultimately required commencement of Cinacalcet 30 mg daily for persistent symptomatic hypercalcaemia. Genetic analysis was subsequently positive for the above variant. Case 2, a 50-year-old female, was referred to the endocrine outpatient clinic for the management of type 2 diabetes and reported a longstanding history of asymptomatic hypercalcaemia which had not been investigated previously. Investigation revealed hypercalcaemia; corrected calcium of 2.6 mmol/L (reference range: 2.21–2.52 mmol/L); PTH of 53.7ng/L (reference range: 15–65 ng/L) and an elevated 24-hour urine calcium of 10 mmol/24 (2.50–7.50 mmol/24hr) with positive genetic analysis and is managed conservatively. Despite sharing this novel mutation, these cases have different phenotypes and their natural history is yet to be determined. Two further relatives are currently undergoing investigation for hypercalcaemia and the family have been referred for genetic counselling.ConclusionAccurate diagnosis of FHH and differentiation from classic primary hyperparathyroidism can be challenging, however it is essential to avoid unnecessary investigations and parathyroid surgery. Genetic analysis may be helpful in establishing a diagnosis of FHH in light of the biochemical heterogeneity in this population and overlap with other causes of hypercalcaemia.

Alexander Munn

An immunohistochemical study of glutathione S-transferase (GST) expression in hepatocellular carcinoma and cholangiocarcinoma is described. Unlike most animal models of hepatic malignancy pi class GST was not consistently overexpressed in...

The Role of Extracellular Matrix in Human Neurodegenerative Diseases.

The dense neuropil of the central nervous system leaves only limited space for extracellular substances free. The advent of immunohistochemistry, soon followed by advanced diagnostic tools, enabled us to explore the biochemical heterogeneity and compartmentalization of the brain extracellular matrix in exploratory and clinical research alike. The composition of the extracellular matrix is critical to shape neuronal function; changes in its assembly trigger or reflect brain/spinal cord malfunction. In this study, we focus on extracellular matrix changes in neurodegenerative disorders. We summarize its phenotypic appearance and biochemical characteristics, as well as the major enzymes which regulate and remodel matrix establishment in disease. The specifically built basement membrane of the central nervous system, perineuronal nets and perisynaptic axonal coats can protect neurons from toxic agents, and biochemical analysis revealed how the individual glycosaminoglycan and proteoglycan components interact with these molecules. Depending on the site, type and progress of the disease, select matrix components can either proactively trigger the formation of disease-specific harmful products, or reactively accumulate, likely to reduce tissue breakdown and neuronal loss. We review the diagnostic use and the increasing importance of medical screening of extracellular matrix components, especially enzymes, which informs us about disease status and, better yet, allows us to forecast illness.

Multiscale Modeling of Glioma Invasion: From Receptor Binding to Flux-Limited Macroscopic PDEs

We propose a novel approach to modeling cell migration in an anisotropic environment with biochemical heterogeneity and interspecies interactions, using as a paradigm glioma invasion in brain tissue under the influence of hypoxia-triggered angiogenesis. The multiscale procedure links single-cell and mesoscopic dynamics with population level behavior, leading on the macroscopic scale to flux-limited glioma diffusion and multiple taxis. We verify the non-negativity of regular solutions (provided they exist) to the obtained macroscopic PDE-ODE system and perform numerical simulations to illustrate the solution behavior under several scenarios.

Nutritional challenges of feeding a mutualist: Testing for a nutrient-toxin tradeoff in fungus-farming leafcutter ants.

The biochemical heterogeneity of food items often yields tradeoffs as each bite of food tends to contain some nutrients in surplus and others in deficit, as well as other less palatable or even toxic compounds. These multidimensional nutritional challenges are likely to be compounded when foraged foods are used to provision others (e.g., offspring or symbionts) with different physiological needs and tolerances. We explored these challenges in free‐ranging colonies of leafcutter ants that navigate a diverse tropical forest to collect plant fragments they use to provision a co‐evolved fungal cultivar. We tested the prediction that leafcutter farmers face provisioning tradeoffs between the nutritional quality and concentration of toxic tannins in foraged plant fragments. Chemical analyses of plant fragments sampled from the mandibles of Panamanian Atta colombica leafcutter ants provided little support for a nutrient–tannin foraging tradeoff. First, colonies foraged for plant fragments that ranged widely in tannin concentration. Second, high tannin levels did not appear to restrict colonies from selecting plant fragments with blends of protein and carbohydrates that maximized cultivar performance when measured with in vitro experiments. We also tested whether tannins expand the realized nutritional niche selected by leafcutter ants into high‐protein dimensions as: (1) tannins can bind proteins and reduce their accessibility during digestion, and (2) in vitro experiments have shown that excess protein provisioning reduces cultivar performance. Contrary to this hypothesis, the most protein‐rich plant fragments did not have highest tannin levels. More generally, the approach developed here can be used to test how multidimensional interactions between nutrients and toxins shape the costs and benefits of providing care to offspring or symbionts.

Features of quantitative EEG in children with hyperkinetic disorder

At the basis of numerous mental disorders lies a synaptic transmission impairment that causes metabolic and ionic changes and affects the current functional state of the brain, the reflection of which we find in electroencephalographic examination.Objective of the study: identification of electroencephalographic features in children under conditions of biochemical heterogeneity of hyperkinetic disorder (HD).Material and methods. 404 children aged 6-8 years with HD were divided into three subgroups according to the state of monoamine activity: the 1-st subgroup with a combination of hypofunction of the dopaminergic and hyperfunction of the noradrenergic systems — 120 children, the 2-nd subgroup with a combination of hyperfunction of the noradrenergic system with relative balance dopamine — 136 children, and the 3-d with a combination of hyperfunction of the dopamine and hypofunction of the noradrenergic systems — 148 children. In the selected groups, the serotonin system plays an inhibitory and modulating role in relation to the catecholamine metabolism systems. The control group consisted of 90 children (54 boys and 36 girls). An electroencephalographic study was carried out, where the following ranges and subranges were differentiated: theta rhythm (4–8 Hz) and beta1 rhythm (14–20 Hz). The power ratios of theta — and — beta1 rhythms (theta/beta1) were calculated.Results. It was the serotonin system that turned out to be the determining factor in the neurophysiological characteristics of HD. Moreover, the division into subgroups, based on the biochemical characteristics of children with HD, did not allow us to obtain significant differences. The only feature that globally distinguishes the subgroups from each other was the increase in the theta/beta1 activity index, corresponding to an increase in the tension and activity of the serotonin system from subgroup 1 to 3. The data obtained allow us to assert that the electroencephalographic index theta / beta1 can serve as a marker of inattention in children with hyperkinetic disorder and reflects the established state of imbalance of all monoamine systems, but better characterizes the behavior of the tryptophan system.Conclusion. The data on the relationship between the power of theta/beta1 rhythms in the EEG may indicate the nature of the activity of the serotonin system in prospective studies, providing a personalized approach to the selection of drug therapy in children with HD.

Alpha-synuclein seeding shows a wide heterogeneity in multiple system atrophy

BackgroundMultiple system atrophy (MSA) is a neurodegenerative condition characterized by variable combinations of parkinsonism, autonomic failure, cerebellar ataxia and pyramidal features. Although the distribution of synucleinopathy correlates with the predominant clinical features, the burden of pathology does not fully explain observed differences in clinical presentation and rate of disease progression. We hypothesized that the clinical heterogeneity in MSA is a consequence of variability in the seeding activity of α-synuclein both between different patients and between different brain regions.MethodsThe reliable detection of α-synuclein seeding activity derived from MSA using cell-free amplification assays remains challenging. Therefore, we conducted a systematic evaluation of 168 different reaction buffers, using an array of pH and salts, seeded with fully characterized brain homogenates from one MSA and one PD patient. We then validated the two conditions that conferred the optimal ability to discriminate between PD- and MSA-derived samples in a larger cohort of 40 neuropathologically confirmed cases, including 15 MSA. Finally, in a subset of brains, we conducted the first multi-region analysis of seeding behaviour in MSA.ResultsUsing our novel buffer conditions, we show that the physicochemical factors that govern the in vitro amplification of α-synuclein can be tailored to generate strain-specific reaction buffers that can be used to reliably study the seeding capacity from MSA-derived α-synuclein. Using this novel approach, we were able to sub-categorize the 15 MSA brains into 3 groups: high, intermediate and low seeders. To further demonstrate heterogeneity in α-synuclein seeding in MSA, we conducted a comprehensive multi-regional evaluation of α-synuclein seeding in 13 different regions from 2 high seeders, 2 intermediate seeders and 2 low seeders.ConclusionsWe have identified unexpected differences in seed-competent α-synuclein across a cohort of neuropathologically comparable MSA brains. Furthermore, our work has revealed a substantial heterogeneity in seeding activity, driven by the PBS-soluble α-synuclein, between different brain regions of a given individual that goes beyond immunohistochemical observations. Our observations pave the way for future subclassification of MSA, which exceeds conventional clinical and neuropathological phenotyping and considers the structural and biochemical heterogeneity of α-synuclein present. Finally, our methods provide an experimental framework for the development of vitally needed, rapid and sensitive diagnostic assays for MSA.

Clinical and Biochemical Heterogeneity of Parkinson’s Disease

Clinical and Biochemical Heterogeneity of Parkinson’s Disease

Primary hyperparathyroidism: Disease of diverse genetic, symptomatic, and biochemical phenotypes.

Genetic, symptomatic, and biochemical heterogeneity of patients with primary hyperparathyroidism (PHPT) has become apparent in recent years. An in-depth, evidence-based review of the phenotypes of PHPT was conducted. This review was intended to provide the resulting information to surgeons who operate on patients with hyperparathyroidism. This review revealed that the once relatively clear distinction between familial and sporadic PHPT has become more challenging by the finding of various germline mutations in patients with seemingly sporadic PHPT. On the one hand, the genetic and clinical characteristics of some syndromes in which PHPT is an important component are now better understood. On the other hand, knowledge is emerging about novel syndromes, such as the rare multiple endocrine neoplasia type IV (MEN4), in which PHPT occurs frequently. It also revealed that, currently, the classical array of symptoms of PHPT is seen rarely upon initial presentation for evaluation. More common are nonspecific, nonclassical symptoms and signs of PHPT. In areas of the world where serum calcium levels are checked routinely, most patients today are "asymptomatic" and they are diagnosed after an incidental finding of hypercalcemia; however, some of them have subclinical involvement of bones and kidneys, which is demonstrated on radiographs, ultrasound, and modern imaging techniques. Last, the review points out that there are three distinct biochemical phenotypes of PHPT. The classical phenotype in which calcium and parathyroid hormone levels are both elevated, and other disease presentations in which the serum levels of calcium or intact parathyroid hormone are normal. Today several, distinct phenotypes of the disease can be identified, and they have implications in the diagnostic evaluation and treatment of patients, as well as possible screening of relatives.