Angelman's syndrome and 15q11-q13 deletion

We discuss the results of cytogenetic reinvestigation in 10 patients with Angelman's syndrome reexamined during the last year. A deletion with 15q11-13 could be demonstrated in 6 of them, confirming that with the available cytogenetic techniques a 15q11-13 deletion is visible and detectable in at least half of the patients with this MCA/MR syndrome. On the other hand, the deletion could not be seen in two affected siblings. This indicates that de novo visible 15q11-13 deletions with low recurrence risk and autosomal recessively inherited cases combine to give an overall sib recurrence risk of less than 25%.     

Chromosome X-linked mental retardation and marfanoid syndrome

In the present paper we report two pairs of slightly to moderately mentally retarded brothers with Marfanoid habitus and similar craniofacial changes. They had a long and narrow face, small mandible, high-arched palate and hypernasal voice, as previously reported by Lujan et al. (1984) in 4 mentally retarded males of a large kindred. The present data suggest the existence of a specific type of X-linked mental retardation with Marfanoid habitus.     

On the nosology of moderate mental retardation with special attention to X-linked mental retardation. A diagnostic genetic survey of 274 institutionalized moderately mentally retarded men

In this paper we report the results of a genetic-diagnostic survey of 274 institutionalized moderately mentally retarded adult males and compare these data with those from our previous studies in the severely mentally retarded and from a comparable population of 262 institutionalized moderately mentally retarded males and females (The Borgenstein experience). Special attention is paid to the nosology of X-linked mental retardation and familial mental retardation in general.     

Possible excess of mental handicap and congenital malformations in autosomal reciprocal translocations.

The most pertinent data of the 32 cases of reciprocal autosomal translocations detected in the laboratory since the initiation of the banding-techniques are summarized. One third of these balanced translocations were detected in patients presenting with mental handicap and/or malformative symptoms.     

Molecular dynamics simulation of shale gas confined inside slit-like calcite [104] nanopore

The growing demand for energy and lack of conventional natural resources has compelled researchers all around the world to pay great attention to the extraction of shale gas, an unconventional natural gas trapped within shale formations. To enhance the gas recovery process and minimise the environmental hazards requires improved technologies. It has been reported that most of the gases trapped in shale rock formations are adsorbed in complex nano-size heterogeneous pores. However, only an insignificant amount of information is available. It is desired to investigate the microscopic behaviour of these gases under nano-confinement for the advancement of enhanced gas recovery (EGR) technologies. In the proposed work, Molecular Dynamics (MD) simulation techniques are used to study the structural and dynamical behaviour of shale gas, which is roughly an 80–20% molar mixture of methane and ethane respectively, confined inside 2.2?nm, slit-like nanopores. The calcite [104] surface has been chosen, as it is the most stable calcite surface. The density profiles of gases are calculated at various temperatures to understand the structural behaviour. The mean square displacements (MSDs) and self-diffusion coefficients are calculated to understand the dynamical behaviour inside the nanopore.     

Heparan sulfate proteoglycans of human lung fibroblasts. Occurrence of distinct membrane, matrix and secreted forms

Human lung fibroblasts (HLF) were labeled with 35SO2-4 for 48 h and extracted with a guanidinium chloride buffer. A fraction of the extracted heparan sulfate proteoglycan (HSPG) appeared micelle-associated. In the absence of detergent these HSPG eluted in the void volume of Sepharose CL2B columns. In the presence of detergent these HSPG were included in Sepharose CL2B (Kav = 0.55) and 4B (Kav = 0.3) columns. This type of HSPG was specifically associated with isolated HLF cell membranes, suggesting that it may represent a fraction of integral membrane proteoglycans. Most of the HSPG in the HLF monolayers, however, eluted in the included volume of Sepharose CL2B (Kav = 0.4) and CL4B (Kav = 0.1) columns in the absence of detergent. This type of HSPG was not affected by detergent and was specifically retained in 'extracellular matrix' preparations. The medium of HLF monolayers contained HSPG of similar Mr as the membrane-associated HSPG. Of these three distinct HSPG fractions only the membrane-associated form could be incorporated in liposomes, confirming that the HSPG in this fraction may be integral membrane components.     

Temporal morphology and cap formation in Acetabularia--I. Light-dark cycle perturbations

Cap formation, a major developmental process in the alga Acetabularia, is influenced by a single perturbation of the entraining light-dark schedule and thus, presumably, of the circadian rhythms. This perturbation is brought about several weeks before cap formation, the most conspicuous expression of morphogenesis in Acetabularia. The effect is more pronounced on cap formation than on growth. It varies in importance with the circadian time at which the perturbation was brought about. The effect is dependent on the developmental state of the alga: transfer carried out during the logarithmic phase of growth produces a delay whose importance decreases with time. When carried out during the phase of slow terminal growth, the transfer induces a transitory acceleration of cap formation. When the algae approach their final length, no effect is elicited. Photoperiodism seems to be involved.     

Increased head circumference and facial cleft as presenting signs of the nevoid basal-cell carcinoma syndrome.

We report a child with nevoid basal-cell carcinoma syndrome (NBCCS) who showed an enlarged head circumference and cleft lip/cleft palate as sole signs of this syndrome at birth. Careful follow up and re-evaluation of this patient enabled us to diagnose the syndrome. Moreover, inspection of her father and sister indicated that they were also affected. An updated review of reported cases indicates that facial cleft occurs in approximately 5% of NBCCS patients. Various aspects of the disease and general measures for its monitoring and treatment are briefly discussed.     

Cultured human fibroblasts contain a large pool of precursor beta 1-integrin but lack an intracellular pool of mature subunit

Previous work has shown the presence of an important intracellular pool of beta 1-integrin subunit in human skin fibroblasts as detected with monoclonal antibody DH12 [De Strooper, B., Van der Schueren, B., Jaspers, M., Saison, M., Spaepen, M., Van Leuven, F., Van den Berghe, H. & Cassiman, J. J. (1989) J. Histochem. Cytochem. 37,299-307]. To analyze this more quantitatively, a radioimmunoassay with radioiodinated monoclonal antibody was developed. The total amount of specific binding sites for monoclonal antibody DH12 on skin fibroblasts was between 0.8-1.5 x 10(6)/cell. After permeabilizing the cells with digitonin, a threefold increase in specific binding was observed, which suggested that about 60% of the total amount of beta 1-subunit was localized intracellularly. From pulse/chase experiments, it was deduced that an important pool of precursor subunit, as defined by its sensitivity to endoglycosidase treatment, existed in fibroblasts. Since in steady-state-labeling conditions, at least three to four times more precursor than mature subunit was immunoprecipitated with monoclonal antibody DH12, we suggested that the intracellular pool of beta 1-integrin subunit is mainly precursor pool. This precursor pool contains a degradation compartment and a maturation compartment. Other investigators have found evidence for a recirculating pool of mature integrin in Chinese hamster ovary cells. Therefore, the presence of a recirculating pool of integrin in human fibroblasts was also considered. The data obtained with mAb DH12 showed that less than 10% of the surface pool of integrin was internalized by endocytosis. Since, however, cross linking of beta 1-integrins with polyclonal antibodies leads to rapid endocytosis of most of the integrin, it remains possible that the quantitatively small effect was actually an artefact induced by the divalent mAb. We conclude that the intracellular pool of beta 1-integrins observed in our previous studies consists of precursor and that in skin fibroblasts no mature beta 1-integrin is available intracellularly for rapid quantitative modulations at the cell surface.     

Effects of forest disturbance on the fitness of an endemic rodent in a biodiversity hotspot

Praomys delectorum occurs abundantly in both disturbed and intact forests in the Ukaguru Mountains within the Eastern Arc Mountains (EAM), Morogoro, Tanzania. While previous studies have reported that anthropogenic disturbances such as grazing, wood cutting, and harvesting have a positive effect on the population density of P. delectorum, the impact of habitat disturbance on its demographic traits is still unknown. We performed a capture–mark–recapture study in both disturbed and intact forests from June 2018 to February 2020 in order to investigate the effects of habitat disturbance on abundance and two demographic traits: survival and maturation of P. delectorum in the Ukaguru Mountains. We found no variation in abundance or maturation between intact and disturbed forests, but habitat type did affect survival. However, this effect was sex‐dependent since female survival was higher in disturbed forests, while male survival remained similar across the two forest types potentially due to differences in predation pressure or food availability between the two habitats. Continuous demographic monitoring of P. delectorum in EAM is necessary given that the increasing human population surrounding the landscape is leading to higher deforestation rates and expansion of the pine plantation in the forest reserve.