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Namacalathus hermanastes is one of the oldest known skeletal metazoans, found in carbonate settings of the terminal Ediacaran (~550-541 million years ago [Ma]). The palaeoecology of this widespread, goblet-shaped, benthic organism is poorly constrained yet critical for understanding the dynamics of the earliest metazoan communities. Analysis of in situ assemblages from the Nama Group, Namibia (~548-541 Ma), shows that Namacalathus exhibited size variation in response to differing water depths, hydrodynamic conditions and substrate types. In low-energy, inner ramp environments, Namacalathus attains the largest average sizes but grew in transient, loosely aggregating, monospecific aggregations attached to microbial mats. In high-energy mid-ramp reefs, Namacalathus spatially segregated into different palaeoecological habitats with distinct size distributions. In outer ramp environments, individuals were small and formed patchy, dense, monospecific aggregations attached to thin microbial mats. Asexual budding is common in all settings. We infer that variations in size distribution in Namacalathus reflect differences in habitat heterogeneity and stability, including the longevity of mechanically stable substrates and oxic conditions. In the Nama Group, long-lived skeletal metazoan communities developed within topographically heterogeneous mid-ramp reefs, which provided diverse mechanically stable microbial substrates in persistently oxic waters, while inner and outer ramp communities were often ephemeral, developing during fleeting episodes of either oxia and/or substrate stability. We conclude that Namacalathus, which forms a component of these communities in the Nama Group, was a generalist that adapted to various palaeoecological habitats within a heterogeneous ecosystem landscape where favourable conditions persisted, and was also able to opportunistically colonise transiently hospitable environments. These early skeletal metazoans colonised previously unoccupied substrates in thrombolitic reefs and other microbial carbonate settings, and while they experienced relatively low levels of interspecific competition, they were nonetheless adapted to the diverse environments and highly dynamic redox conditions present in the terminal Ediacaran. [ABSTRACT FROM AUTHOR]

Forty-six patients with histologically confirmed lung cancer received treatment with the cytotoxic drug VP-16-213 in a dose of 100 mg twice daily, given orally for five days. The overall objective response rate was 11 out of 46 (24%) or 11 of the 33 (33%) who survived to receive two cycles. The drug was effective in all histological types. Only one patient developed leucopenia. This demonstration of the safety of VP-16-213 and its effectiveness suggested that this drug might be used in combination chemotherapy. A series of pilot studies showed unexplained marrow toxicity when VP-16-123 combined with vincristine was given with either methotrexate of adriamycin. [ABSTRACT FROM AUTHOR]

Oxygenation during the Cambrian Radiation progressed via a series of short-lived pulses. However, the metazoan biotic response to this episodic oxygenation has not been quantified, nor have the causal evolutionary processes been constrained. Here we present ecological analyses of Cambrian archaeocyath sponge reef communities on the Siberian Platform (525-514 Ma). During the oxic pulse at ~521-519 Ma, we quantify reef habitat expansion coupled to an increase in reef size and metacommunity complexity, from individual within-community reactions to their local environment, to ecologically complex synchronous community-wide response, accompanied by an increase in rates of origination. Subsequently, reef and archaeocyath body size are reduced in association with increased rates of extinction due to inferred expanded marine anoxia (~519-516.5 Ma). A later oxic pulse at ~515 Ma shows further reef habitat expansion, increased archaeocyath body size and diversity, but weaker community-wide environmental responses. These metrics confirm that oxygenation events created temporary pulses of evolutionary diversification and enhanced ecosystem complexity, potentially via the expansion of habitable space, and increased archaeocyath individual and reef longevity in turn leading to niche differentiation. Most notably, we show that progression towards increasing biodiversity and ecosystem complexity was episodic and discontinuous, rather than linear, during the Cambrian Radiation., (© 2022. The Author(s).)

The 'Cambrian Explosion' describes the rapid increase in animal diversity and abundance, as manifest in the fossil record, between ~540 and 520 million years ago (Ma). This event, however, is nested within a far more ancient record of macrofossils extending at least into the late Ediacaran at ~571 Ma. The evolutionary events documented during the Ediacaran-Cambrian interval coincide with geochemical evidence for the modernisation of Earth's biogeochemical cycles. Holistic integration of fossil and geochemical records leads us to challenge the notion that the Ediacaran and Cambrian worlds were markedly distinct, and places biotic and environmental change within a longer-term narrative. We propose that the evolution of metazoans may have been facilitated by a series of dynamic and global changes in redox conditions and nutrient supply, which, potentially together with biotic feedbacks, enabled turnover events that sustained multiple phases of radiation. We argue that early metazoan diversification should be recast as a series of successive, transitional radiations that extended from the late Ediacaran and continued through the early Palaeozoic. We conclude that while the Cambrian Explosion represents a radiation of crown-group bilaterians, it was simply one phase amongst several metazoan radiations, some older and some younger.

Reef-building in metazoans represents an important ecological innovation whereby individuals collectively enhance feeding efficiency and gain protection from competitors and predation. The appearance of metazoan reefs in the fossil record therefore indicates an adaptive response to complex ecological pressures. In the Nama Group, Namibia, we found evidence of reef-building by the earliest known skeletal metazoan, the globally distributed Cloudina, ~548 million years ago. These Cloudina reefs formed open frameworks without a microbial component but with mutual attachment and cementation between individuals. Orientated growth implies a passive suspension-feeding habit into nutrient-rich currents. The characteristics of Cloudina support the view that metazoan reef-building was promoted by the rise of substrate competitors and predators., (Copyright © 2014, American Association for the Advancement of Science.)

This article reviews selected issues of endocrine concerns in the pediatric intensive care unit, exclusive of diabetic ketoacidosis. The sympathoadrenergic arm of the neuroendocrine stress response is described, followed by discussions of two topics of particular current concern: critical illness hyperglycemia and relative adrenal insufficiency. A selected set of common scenarios encountered in the daily practice of intensive care follows.

Three categories of precursor cells have been identified in postnatal mammals: tissue-committed progenitor cells, germ layer lineage-committed stem cells and lineage-uncommitted pluripotent stem cells. Progenitor cells are the immediate precursors of differentiated tissues. Germ layer lineage stem cells can be induced to form multiple cell types belonging to their respective ectodermal, mesodermal, and endodermal embryological lineages. Pluripotent stem cells will form somatic cell types from all three primary germ layer lineages. Progenitor cells demonstrate a finite life span before replicative senescence and cell death occur. Both germ layer lineage stem cells and pluripotent stem cells are telomerase positive and display extensive capabilities for self-renewal. Stem cells which undergo such extensive replication have the potential for undergoing mutations that may subsequently alter cellular functions. Gross mutations in the genome may be visualized as chromosomal aneuploidy and/or chromosomes that appear aberrant. This study was designed to determine whether any gross genomic mutations occurred within the adult pluripotent stem cells. Karyotypic analysis was performed using pluripotent stem cells purified from adult male rats using established procedures. Giemsa Banding was used in conjunction with light microscopy to visualize metaphase chromosome spreads. To date over 800 metaphase spreads have been analyzed. We found that the metaphase spreads averaged 42 chromosomes and concluded that these pluripotent stem cells isolated from adult rats have a normal karyotype.

Albright hereditary osteodystrophy (AHO) is a condition with characteristic physical findings (short stature, obesity, round face, brachydactyly) but variable biochemical changes (pseudohypoparathyroidism, pseudopseudohypoparathyroidism). Most patients with AHO have decreased activity of the guanine nucleotide-binding protein (GS protein) that stimulates adenylyl cyclase. The gene encoding the alpha subunit of the GS protein (GNAS1) has been mapped to the long arm of chromosome 20. We describe 4 unrelated individuals with apparent AHO, associated with small terminal deletions of chromosome 2. All 4 patients had normal serum calcium levels consistent with pseudopseudohypoparathyroidism. Del(2) (q37) is the first consistent karyotypic abnormality that has been documented in AHO [Phelan et al., 1993: Am J Hum Genet 53:484]. The finding of the same small terminal deletion in 4 unrelated individuals with a similar phenotype suggests that a gene locus in the 2q37 region is important in the pathogenesis of Albright syndrome. The association of Albright syndrome and the GNAS1 locus on chromosome 20 is well documented. The observation of a second potential disease locus on chromosome 2 may help explain the heterogeneity observed in this disorder.

Serum thyroxine values were determined prospectively over a 6-month interval in 97 newborn infants with birth weight < 2200 gm or gestational age < 37 weeks. There were 89 survivors and 8 deaths. Infants with thyroxine values of < 2.5 micrograms/dl (32.2 nmol/L) had a significantly higher mortality rate (p < 0.001) compared with infants with higher thyroxine levels. In neonates there may exist a critical thyroxine value below which there is an increased risk of mortality.

Asymmetrical limitation of abduction of the hip may be found on screening of children in the first year of life. The clinical features identified may occur in congenital dislocation of the hip but most infants do not have or develop hip dislocation. Radiological changes are present on the side of limitation of abduction and include a higher acetabular angle, retardation of femoral head epiphyseal development, pelvic obliquity and a rotational deformation of the pelvis in the transaxial plane. The appearances are postural deformities due to persistent infant positioning and are self-correcting. If aggressive treatment methods are to be avoided, the radiologist should not confuse these changes with those of congenital hip dislocation or subluxation.

A patient with partial duplication 2q and partial deficiency 11q is reported. The propositus was delivered at 30 weeks gestation, with a birth weight of 1,390 g. He had severe hyaline membrane disease, intraventricular hemorrhage, bronchopulmonary dysplasia, hypotonia, psychomotor retardation, hearing loss, and other anomalies including a short bitemporal diameter, prominent occiput, low-set ears, exophthalmos, short nose with depressed nasal root, downturned mouth corners, narrow high-arched palate, micrognathia, a deep longitudinal groove over the sacrococcygeal region, clinodactyly, and abnormal dermatoglyphics. Chromosome analysis showed the following karyotype: 46,XY,der11,t(2:11)(q32.2;q25)pat.

The clinical and radiological features of five patients with hydatid cyst of the pelvis are presented. The cysts were found in the following sites: the broad ligament, the pararectal soft tissues, the greater omentum, the ala of the sacrum and in the retrovesical space. Hydatid disease should be considered in the differential diagnosis of unusual cystic swellings in the pelvis, particularly in patients who have lived in endemic areas.