Nutrient supply, cell spatial correlation and Gompertzian tumor growth.

Gompertzian tumor growth can be reproduced by mitosis, related to nutrient supply, with local spatial cell correlations. The global energy constraint alone does not reproduce in vivo data by the observed values of the nutrient expenditure for the cell activities. The depletion of the exponential growth, described by the Gompertz law, is obtained by mean field spatial correlations or by a small word network among cells. The well-known interdependence between the two parameters of the Gompertz growth naturally emerges and depends on the cell volume and on the tumor density.

Containment effort reduction and regrowth patterns of the Covid-19 spreading.

In all countries the political decisions aim to achieve an almost stable configuration with a small number of new infected individuals per day due to Covid-19. When such a condition is reached, the containment effort is usually reduced in favor of a gradual reopening of the social life and of the various economical sectors. However, in this new phase, the infection spread restarts and, moreover, possible mutations of the virus give rise to a large specific growth rate of the infected people. Therefore, a quantitative analysis of the regrowth pattern is very useful. We discuss a macroscopic approach which, on the basis of the collected data in the first lockdown, after few days from the beginning of the new phase, outlines different scenarios of the Covid-19 diffusion for longer time. The purpose of this paper is a demonstration-of-concept: one takes simple growth models, considers the available data and shows how the future trend of the spread can be obtained. The method applies a time dependent carrying capacity, analogously to many macroscopic growth laws in biology, economics and population dynamics. The illustrative cases of France, Italy and United Kingdom are analyzed.

Usher syndrome: an effective sequencing approach to establish a genetic and clinical diagnosis.

Usher syndrome is an autosomal recessive disorder characterized by retinitis pigmentosa, sensorineural hearing loss and, in some cases, vestibular dysfunction. The disorder is clinically and genetically heterogeneous and, to date, mutations in 11 genes have been described. This finding makes difficult to get a precise molecular diagnosis and offer patients accurate genetic counselling. To overcome this problem and to increase our knowledge of the molecular basis of Usher syndrome, we designed a targeted resequencing custom panel. In a first validation step a series of 16 Italian patients with known molecular diagnosis were analysed and 31 out of 32 alleles were detected (97% of accuracy). After this step, 31 patients without a molecular diagnosis were enrolled in the study. Three out of them with an uncertain Usher diagnosis were excluded. One causative allele was detected in 24 out 28 patients (86%) while the presence of both causative alleles characterized 19 patients out 28 (68%). Sixteen novel and 27 known alleles were found in the following genes: USH2A (50%), MYO7A (7%), CDH23 (11%), PCDH15 (7%) and USH1G (2%). Overall, on the 44 patients the protocol was able to characterize 74 alleles out of 88 (84%). These results suggest that our panel is an effective approach for the genetic diagnosis of Usher syndrome leading to: 1) an accurate molecular diagnosis, 2) better genetic counselling, 3) more precise molecular epidemiology data fundamental for future interventional plans.

Emerging ciliopathies: are respiratory cilia compromised in Usher syndrome?

PURPOSE: Usher syndrome is a ciliopathy involving photoreceptors and cochlear hair cells (sensory cilia): since sensory and motor ciliopathies can overlap, we analysed the respiratory cilia (motile) in 17 patients affected by Usher syndrome and 18 healthy control subject. PATIENTS AND METHODS: We studied the mucociliary transport time with the saccharine test, ciliary motility and ultrastructure of respiratory cilia obtained by nasal brushing; we also recorded the classical respiratory function values by spirometry. RESULTS: All enrolled subjects showed normal respiratory function values. The mean mucociliary transport time with saccharine was 22.33 ± 17.96 min, which is in the range of normal values. The mean ciliary beat frequency of all subjects was 8.81 ± 2.18 Hz, which is a value approaching the lower physiological limit. None of the classical ciliary alterations characterizing the "ciliary primary dyskinesia" was detected, although two patients showed alterations in number and arrangement of peripheral microtubules and one patient had abnormal ciliary roots. CONCLUSIONS: Respiratory cilia in Usher patients don't seem to have evident ultrastructural alterations, as expected, but the fact that the ciliary motility appeared slightly reduced could emphasize that a rigid distinction between sensory and motor ciliopathies may not reflect what really occurs.

Nuclear shadowing in the holographic framework.

The nucleon structure function F2(N) computed in a holographic framework can be used to describe nuclear deep inelastic scattering effects provided that a rescaling of the Q2 momentum and of the IR hard-wall parameter z0 is made. The ratios RA=F2(A)/F2(N) can be obtained in terms of a single rescaling parameter λA for each nucleus. The resulting ratios agree with the experiment in a wide range of the shadowing region.

Unbiased next generation sequencing analysis confirms the existence of autosomal dominant Alport syndrome in a relevant fraction of cases.

The mode of inheritance of Alport syndrome (ATS) has long been controversial. In 1927, the disease was hypothesized as a dominant condition in which males were more severely affected than females. In 1990, it was considered an X-linked (XL) semidominant condition, due to COL4A5 mutations. Later on, a rare autosomal recessive (AR) form due to COL4A3/COL4A4 mutations was identified. An autosomal dominant (AD) form was testified more recently by the description of some large pedigrees but the real existence of this form is still questioned by many and its exact prevalence is unknown. The introduction of next generation sequencing (NGS) allowed us to perform an unbiased simultaneous COL4A3-COL4A4-COL4A5 analysis in 87 Italian families (273 individuals) with clinical suspicion of ATS. In 48 of them (55%), a mutation in one of the three genes was identified: the inheritance was XL semidominant in 65%, recessive in 4% and most interestingly AD in 31% (15 families). The AD form must therefore be seriously taken into account in all pedigrees with affected individuals in each generation. Furthermore, a high frequency of mutations (>50%) was shown in patients with only 1 or 2 clinical criteria, suggesting NGS as first-level analysis in cases with a clinical suspicion of ATS.

Growth laws in cancer: implications for radiotherapy.

Comparing the conventional Gompertz tumor growth law (GL) with the "Universal" law (UL), which has recently been proposed and applied to cancer, we have investigated the implications of the growth laws for various radiotherapy regimens. According to the GL, the surviving tumor cell fraction could be reduced ad libitum, independent of the initial tumor mass, simply by increasing the number of treatments. In contrast, if tumor growth dynamics follows the Universal scaling law, there is a lower limit of the surviving fraction that cannot be reduced further regardless of the total number of treatments. This finding can explain the so-called tumor size effect and re-emphasizes the importance of early diagnosis because it implies that radiotherapy may be successful provided that the tumor mass at treatment onset is rather small. Taken together with our previous work, the implications of these findings include revisiting standard radiotherapy regimens and treatment protocols overall.

Classification scheme for phenomenological universalities in growth problems in physics and other sciences.

A classification in universality classes of broad categories of phenomenologies, belonging to physics and other disciplines, may be very useful for a cross fertilization among them and for the purpose of pattern recognition and interpretation of experimental data. We present here a simple scheme for the classification of nonlinear growth problems. The success of the scheme in predicting and characterizing the well known Gompertz, West, and logistic models, suggests to us the study of a hitherto unexplored class of nonlinear growth problems.

A novel dominant missense mutation--D179N--in the GJB2 gene (Connexin 26) associated with non-syndromic hearing loss.

Mutations of the GJB2 gene, encoding Connexin 26, are the most common cause of hereditary congenital hearing loss in many countries, and account for up to 50% of cases of autosomal-recessive non-syndromic deafness. By contrast, only a few GJB2 mutations have been reported to cause an autosomal-dominant form of non-syndromic deafness. We report on a family from southern Italy in whom dominant, non-syndromic, post-lingual hearing loss is associated with a novel missense mutation in the GJB2 gene. Direct sequencing of the gene showed a heterozygous G-->A transition at nucleotide 535, resulting in an aspartic acid to asparagine amino acid substitution at codon 179 (D179N). This mutation occurred in the second extracellular domain (EC2), which would seem to be very important for connexon-connexon interaction.

[Rothmund-Thomson syndrome, trisomy 8 mosaicism and RECQ4 gene mutation]. / Syndrome de Rothmund-Thomson, trisomie 8 en mosaïque et mutation du gène RECQ4.

BACKGROUND: We report a case of Rothmund-Thomson syndrome associated with a trisomy 8 mosaicism, and RECQ4 gene mutation. OBSERVATION: An 18-year-old man presented with a poikiloderma affecting photoexposed areas and the buttocks. This lesions appeared during the first year of life and was secondly associated with alopecia, sparse body hair, keratosis, and warts. He also had proportional short stature, thumb and patella aplasia, particular facies, and plantar malformations. Cytogenetic studies evidenced chromosomal instability and trisomy 8 mosaicism. The DNA repair capacity was normal. A mutation in RECQ4 helicase gene was found. DISCUSSION: Rothmund-Thomson syndrome is a rare hereditary syndrome characterized by early onset of poikiloderma. Patients exhibit variable features including skeletal abnormalities, juvenile cataracts, photosensitivity, and a higher than expected incidence of cutaneous or extracutaneous malignancies. Genetic patterns found in Rothmund-Thomson syndrome are heterogeneous. Normal karyotypes have been demonstrated in many patients. Various karyotypic abnormalities or reduced DNA repair was seen in others. Recently, five patients with Rothmund-Thomson syndrome were shown to segregate for mutations in RECQ4 helicase gene. Thus, clinical and genetic features in Rothmund-Thomson syndrome are polymorphous. Therefore, it could be interesting to correlate genotype and phenotype.

Multicolor FISH in chronic lymphocytic leukemia. An interphase study of patients with early-onset disease.

Trisomy 12 and deletions of 13q14.2 and 14q32 are the most common chromosome abnormalities in patients with B-chronic lymphocytic leukemia (B-CLL), but whether specific chromosomal defects influence the course of B-CLL is still a matter of discussion. The aim of our study was to assess the possible correlation between cytogenetic findings and clinical characteristics. Thirty patients with previously untreated early-onset B-CLL were recruited. The incidence of trisomy 12, and observations of 13q14.2 and 14q32 was analyzed in unstimulated bone marrow cells by means of multicolor interphase FISH. No correlation was found between trisomy 12 and the patients' clinical characteristics. The analysis of the patients with trisomy 12 and observations of 13q14.2 and 14q32 revealed heterogeneity of the leukemic cell population, thus indicating that these chromosomal abnormalities are probably a secondary event in CLL leukemogenesis. The finding of RB1 gene nullisomy and 14q32 deletions in patients at an advanced clinical stage suggests a possible correlation between these rearrangements and disease progression. Multicolor FISH analysis in B-CLL provides important diagnostic, clinical, and prognostic information that may help in assessing prognosis and making treatment decisions.

Reproductive follow-up of carriers of familial reciprocal balanced translocations involving chromosome 9 and comparison with predicted outcome.

Reproductive follow-up of carriers of familial reciprocal balanced translocations involving chromosome 9 and comparison with predicted outcome: Chromosome 9 is commonly implicated in reciprocal translocations (rcp). Twenty-seven families segregating rcp involving chromosome 9 were selected with the aim of comparing the theoretical risk of Mental Retardation with Congenital Anomalies (MCA/MR) calculated according to Human Cytogenetics Forum with the observed reproductive follow-up. The 27 families include 157 subjects. The reproductive follow-up showed that the majority of mothers underwent full-term pregnancies (88/130), and that there were 37 spontaneous and five voluntary abortions. Eighty-one subjects were karyotyped: 18 had a normal karyotype, 50 carried an rcp, ten had an unbalanced rcp-related karyotype and three an abnormal rcp-unrelated karyotype. Of the 88 live-born individuals, seven had an abnormal rcp-related karyotype with partial chromosome 9 trisomy (four cases) or partial 9p monosomy (three cases), and 48 were rcp carriers, two of whom also presented additional anomalies. The evaluation of reproductive outcomes in the 27 families studied revealed good concordance between the Human Cytogenetics Forum predictions and the observed follow-up in relation to the most probable mode of unbalance at birth, and the higher risk of MCA/MR in rcp carriers with unbalanced live-borns in comparison with those generating healthy progeny

Trisomy 4 leading to duplication of a mutated KIT allele in acute myeloid leukemia with mast cell involvement.

A G-->T transversion at nucleotide 2467 of the c-KIT gene leading to Asp816-->Tyr (D816Y) substitution in the phosphotransferase domain has been previously identified in a patient with rapidly progressing AML-M2 and mast cell involvement; the patient's blasts had a 47,XY, +4,t(8;21)(q22;q22) karyotype. Herein we confirm the simultaneous presence of both major chromosomal changes by multicolor fluorescence in situ hybridization (FISH) on interphase CD34+ mononuclear cells. By setting up culture leukemic blasts, spontaneous differentiation of adherent cells with mast-cell like features was proved by histochemical and immunoenzymatic analyses. Fluorescence in situ hybridization evidence of trisomy 4 confirmed the origin of differentiated cells from the leukemic blasts. Semiquantitative polymerase chain reaction (PCR) and phosphoimage densitometry of wild-type and mutated KIT alleles on bone marrow blasts made it possible to demonstrate that chromosome 4 trisomy led to a double dosage of the mutated KIT allele. This finding, and that of trisomy 7 and MET mutation in hereditary renal carcinoma represent the only cases of human tumors in which an increased number of chromosomes carrying an oncogene activated by point mutation have been detected.

NF1 microdeletion syndrome: refined FISH characterization of sporadic and familial deletions with locus-specific probes.

Two familial and seven sporadic patients with neurofibromatosis 1-who showed dysmorphism, learning disabilities/mental retardation, and additional signs and carried deletions of the NF1 gene-were investigated by use of a two-step FISH approach to characterize the deletions. With FISH of YAC clones belonging to a 7-Mb 17q11.2 contig, we estimated the extension of all of the deletions and identified the genomic regions harboring the breakpoints. Mosaicism accounted for the mild phenotype in two patients. In subsequent FISH experiments, performed with locus-specific probes generated from the same YACs by means of a novel procedure, we identified the smallest region of overlapping (SRO), mapped the deletion breakpoints, and identified the genes that map to each deletion interval. From centromere to telomere, the approximately 0.8-Mb SRO includes sequence-tagged site 64381, the SUPT6H gene (encoding a transcription factor involved in chromatin structure), and NF1. Extending telomerically from the SRO, two additional genes-BLMH, encoding a hydrolase involved in bleomycin resistance, and ACCN1, encoding an amiloride-sensitive cation channel expressed in the CNS-were located in the deleted intervals of seven and three patients, respectively. An apparently common centromeric deletion breakpoint was shared by all of the patients, whereas a different telomeric breakpoint defined a deletion interval of 0.8-3 Mb. There was no apparent correlation between the extent of the deletion and the phenotype. This characterization of gross NF1 deletions provides the premise for addressing correctly any genotype-phenotype correlation in the subset of patients with NF1 deletions.

Chromosomal instability in fibroblasts and mesenchymal tumors from 2 sibs with Rothmund-Thomson syndrome.

Rothmund-Thomson syndrome (RTS) is a rare autosomal recessive genodermatosis associated with increased risk of mesenchymal tumors. The putative gene has been provisionally assigned to chromosome 8. Using a cytogenetic-molecular approach, we studied lymphocytes, fibroblasts, osteosarcoma (OS) and malignant fibrous histiocytoma (MFH) from 2 affected fraternal twins, looking for constitutive markers of chromosome instability and tumor chromosomal changes which might reflect the common genetic background. The rate of spontaneous chromosome aberrations was not increased in lymphocytes. Conversely, karyotyping of primary fibroblasts from one sib evidenced chromosome breaks and both numerical and structural chromosome changes in 24% and 17% of the metaphases respectively. FISH of a 8q21.3 cosmid allowed us to detect trisomy of the target region on 7% of fibroblast nuclei from both sibs, 47% and 12% of OS and MFH cells. Pronounced chromosomal instability and clonal rearrangements leading to different chromosome-8 derivatives were detected in both tumors. CGH experiments showed multiple gains/losses, among which del(6q), also revealed by cytogenetics, and 7p gain were common, whereas 8q amplification was present only in OS. Chromosomal instability, observed in fibroblasts from the RTS patients studied, accounts for the increased risk of mesenchymal tumors in these patients.

Genotype-phenotype correlation in two sets of monozygotic twins with Williams syndrome.

We report on two sets of monozygotic (MZ) twins with Williams syndrome (WS), following the 6 pairs already reported in the literature. We have confirmed monozygosity of both pairs of twins by DNA microsatellite analysis and the clinical diagnosis by fluorescence in situ hybridization using a WS-specific probe. Analysis of the concordance of different clinical signs between members of each pair of twins benefitted from a lengthy clinical follow-up, from 24 months to 7 years in one pair, and from the age of 15 years with reevaluation after 2 years in the other pair. Most clinical signs were concordant in the twins of each pair, with differences present at younger ages, mainly minor facial anomalies, being attenuated with time. Developmental delay was substantially concordant, but the degree differed slightly between twins in each pair. Inguinal hernia was present in a single twin in pair 1. Facial anomalies and other signs attributable to connective tissue abnormalities were also displayed by only one twin in both sets, suggesting that the WS genotype has only a predisposing role in the development of these signs.

Characterization of a cytogenetic 17q11.2 deletion in an NF1 patient with a contiguous gene syndrome.

We report on a rare patient screened as a putative carrier of a contiguous gene syndrome on the basis of a complex phenotype characterized by sporadic neurofibromatosis type 1 (NF1), dysmorphism, mental retardation and severe skeletal anomalies. A cytogenetically visible 17q11.2 deletion was detected in the patient's karyotype by high-resolution banding and confirmed by fluorescence in situ hybridization with yeast artificial chromosomes targeting the NF1 region. Analysis of the segregation from parents to proband of 13 polymorphic DNA markers, either contiguous or contained within the NF1 gene, showed that the patient is hemizygous at sites within the NF1 gene-the AAAT-Alu repeat in the 5' region of intron 27b, the CA/GT microsatellite in the 3' region of intron 27b, and the CA/GT microsatellite in intron 38- and at the extragenic D17S798 locus, distal to the 3' end of NF1. The patient may be an important resource in the identification of genes downstream of NF1 that may contribute to some of his extra-NF1 clinical signs.