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Purple sea urchins (Strongylocentrotus purpuratus) profoundly impact nearshore rocky coasts through their feeding habits. Their intense grazing sculpts substrates through bioerosion using their teeth and spines and controls the alternative stable state dynamic between kelp bed and urchin barrens. These states have contrasting food availability for sea urchins, with abundant food in kelp beds and scarce food in barren grounds. However, the relationship between food availability and bioerosion is unknown. We predicted that when kelp is available, it would ameliorate the action of teeth on the substrate. Our 11-week long, 2 × 2 factorial experiment, crossed community state (kelp present vs absent) and rock type (sandstone vs mudstone). We also quantified the contribution of spine abrasion to bioerosion on the two rock types. The bioerosion rates did not differ between treatments with and without kelp. Although there was no significant difference in net bioerosion between the rock types, there was a large difference between the proportion of bioerosion from teeth vs spine abrasion. Approximately a third of the sandstone bioerosion was from spines whereas less than 2% of mudstone bioerosion could be attributed to spines. As anticipated, growth of sea urchins fed kelp ad-libitum was higher than food-limited sea urchins. Surprisingly, sea urchins on mudstone (which has a higher organic component) grew faster than sea urchins on sandstone. Although bioerosion rates may not differ on a per-urchin basis between community states, the sea urchin population densities between kelp beds and urchin barrens likely causes a difference in net bioerosion between these communities. Our results point to the importance of lithology on the mechanics of sea urchin bioerosion. Differences in texture, grain size, and hardness of rock substrates undoubtedly contribute to bioerosion rates and dynamics., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology.)

Climate change will increase the frequency and intensity of extreme climatic events (e.g., storms) that result in repeated pulses of hyposalinity in nearshore ecosystems. Sea urchins inhabit these ecosystems and are stenohaline (restricted to salinity levels ∼32‰), thus are particularly susceptible to hyposalinity events. As key benthic omnivores, sea urchins use hydrostatic adhesive tube feet for numerous functions, including attachment to and locomotion on the substratum as they graze for food. Hyposalinity severely impacts sea urchin locomotor and adhesive performance but several ecologically relevant and climate change-related questions remain. First, do sea urchin locomotion and adhesion acclimate to repeated pulses of hyposalinity? Second, how do tube feet respond to tensile forces during single and repeated hyposalinity events? Third, do the negative effects of hyposalinity exposure persist following a return to normal salinity levels? To answer these questions, we repeatedly exposed green sea urchins (Strongylocentrotus droebachiensis) to pulses of three different salinities (control: 32‰, moderate hyposalinity: 22‰, severe hyposalinity: 16‰) over the course of two months and measured locomotor performance, adhesive performance, and tube foot tensile behavior. We also measured these parameters 20 h after sea urchins returned to normal salinity levels. We found no evidence that tube feet performance and properties acclimate to repeated pulses of hyposalinity, at least over the timescale examined in this study. In contrast, hyposalinity has severe consequences on locomotion, adhesion, and tube foot tensile behavior, and these impacts are not limited to the hyposalinity exposure. Our results suggest both moderate and severe hyposalinity events have the potential to increase sea urchin dislodgment and reduce movement, which may impact sea urchin distribution and their role in marine communities., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology.)

Sea urchins rely on an adhesive secreted by their tube feet to cope with the hydrodynamic forces of dislodgement common in nearshore, high wave-energy environments. Tube feet adhere strongly to the substrate and detach voluntarily for locomotion. In the purple sea urchin, Strongylocentrotus purpuratus , adhesive performance depends on both the type of substrate and the population of origin, where some substrates and populations are more adhesive than others. To explore the source of this variation, we evaluated tube foot morphology (disc surface area) and mechanical properties (maximum disc tenacity and stem breaking force) of populations native to substrates with different lithologies: sandstone, mudstone, and granite. We found differences among populations, where sea urchins native to mudstone substrates had higher disc surface area and maximum disc tenacity than sea urchins native to sandstone substrates. In a lab-based reciprocal transplant experiment, we attempted to induce a plastic response in tube foot morphology. We placed sea urchins on nonnative substrates (i.e., mudstone sea urchins were placed on sandstone and vice versa), while keeping a subgroup of both populations on their original substrates as a control. Instead of a reciprocal morphological response, we found that all treatments, including the control, reduced their disc area in laboratory conditions. The results of this study show differences in morphology and mechanical properties among populations, which explains population differences in adhesive performance. Additionally, this work highlights the importance of considering the impact of phenotypic plasticity in response to captivity when interpreting the results of laboratory studies., Competing Interests: The authors declare no competing interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology.)

Climate change will increase the frequency and intensity of low-salinity (hyposalinity) events in coastal marine habitats. Sea urchins are dominant herbivores in these habitats and are generally intolerant of salinity fluctuations. Their adhesive tube feet are essential for survival, effecting secure attachment and locomotion in high wave energy habitats, yet little is known about how hyposalinity impacts their function. We exposed green sea urchins (Strongylocentrotus droebachiensis) to salinities ranging from ambient (32‰) to severe (14‰) and assessed tube feet coordination (righting response, locomotion) and adhesion [disc tenacity (force per unit area)]. Righting response, locomotion and disc tenacity decreased in response to hyposalinity. Severe reductions in coordinated tube foot activities occurred at higher salinities than those that affected adhesion. The results of this study suggest moderate hyposalinities (24-28‰) have little effect on S. droebachiensis dislodgement risk and survival post-dislodgment, while severe hyposalinity (below 24‰) likely reduces movement and prevents recovery from dislodgment., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

Regenerating structures critical for survival provide excellent model systems for the study of phenotypic plasticity. These body components must regenerate their morphology and functionality quickly while subjected to different environmental stressors. Sea urchins live in high-energy environments where hydrodynamic conditions pose significant challenges. Adhesive tube feet provide secure attachment to the substratum but can be amputated by predation and hydrodynamic forces. Tube feet display functional and morphological plasticity in response to environmental conditions, but regeneration to their pre-amputation status has not been achieved under quiescent laboratory settings. In this study, we assessed the effect of turbulent water movement, periodic emersion and quiescent conditions on the regeneration process of tube foot morphology (length, disc area) and functionality (maximum disc tenacity, stem breaking force). Disc area showed significant plasticity in response to the treatments; when exposed to emersion and turbulent water movement, disc area was larger than that of tube feet regenerated in quiescent conditions. However, no treatment stimulated regeneration to pre-amputation sizes. Tube foot length was unaffected by treatments and remained shorter than non-amputated tube feet. Stem breaking force for amputated and non-amputated treatments increased in all cases when compared with pre-amputation values. Maximum tenacity (force per unit area) was similar among tube feet subjected to simulated field conditions and amputation treatments. Our results suggest a role of active plasticity of tube foot functional morphology in response to field-like conditions and demonstrate the plastic response of invertebrates to laboratory conditions., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)

Sea urchins native to the nearshore open coast experience periods of high, repeated wave forces that can result in dislodgement. To remain attached while clinging and locomoting across rocky substrates, sea urchins use adhesive tube feet. Purple sea urchins ( Strongylocentrotus purpuratus ) adhere to a variety of rock substrates (e.g. sandstone, mudstone, granite), and display morphological plasticity (skeletal morphology) to native substrate. We tested the hypothesis that their adhesive system is also plastic and varies as a function of native population and substrate. The results of our study support our hypothesis. Sea urchins from sandstone adhere less strongly to most substrates than those native to mudstone and granite rock. Sandstone produced the lowest whole animal adhesive force values across all populations, suggesting that this rock type is particularly challenging for sea urchins to adhere to. The number of adhesive tube feet that failed during experimental trials and the area used by sea urchins to attach, matches closely with whole animal adhesive force values: higher forces resulted in more tube foot failure and larger attachment area. On artificial substrates (glass and Plexiglass), differences in adhesion among populations was consistent with differences in adhesion on rock substrates except on glass, where sea urchins native to sandstone adhered more strongly to glass than any other substrate tested. To our knowledge, this study is the first to describe population-level plasticity in a biological adhesive system related to native substrate, and has significant implications for sea urchin ecology, behavior and functional morphology., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2020. Published by The Company of Biologists Ltd.)

Sea urchins are dominant members of rocky temperate reefs around the world. They often occur in cavities within the rock, and fit so tightly, it is natural to assume they sculpted these "pits." However, there are no experimental data demonstrating they bore pits. If they do, what are the rates and consequences of bioerosion to nearshore systems? We sampled purple sea urchins, Strongylocentrotus purpuratus, from sites with four rock types, three sedimentary (two sandstones and one mudstone) and one metamorphic (granite). A year-long experiment showed urchins excavated depressions on sedimentary rocks in just months. The rate of pit formation varied with rock type and ranged from <5 yr for medium-grain sandstone to >100 yr for granite. In the field, there were differences in pit size and shapes of the urchins (height:diameter ratio). The pits were shallow and urchins flatter at the granite site, and the pits were deeper and urchins taller at the sedimentary sites. Although overall pit sizes were larger on mudstone than on sandstone, urchin size accounted for this difference. A second, short-term experiment, showed the primary mechanism for bioerosion was ingestion of the substratum. This experiment eliminated potential confounding factors of the year-long experiment and yielded higher bioerosion rates. Given the high densities of urchins, large amounts of rock can be converted to sediment over short time periods. Urchins on sandstone can excavate as much as 11.4 kg m-2 yr-1. On a broader geographic scale, sediment production can exceed 100 t ha-1 yr-1, and across their range, their combined bioerosion is comparable to the sediment load of many rivers. The phase shift between urchin barrens and kelp bed habitats in the North Pacific is controlled by the trophic cascade of sea otters. By limiting urchin populations, these apex predators also may indirectly control a substantial component of coastal rates of bioerosion.

Purpose: In this prospective preliminary study we evaluated changes of prostate volume and changes of brachytherapy treatment plan parameters due to interstitial hyperthermia (IHT) applied prior to high-dose-rate brachytherapy (HDRBT), compared to our standard HDRBT procedure., Material and Methods: In a group of 60 consecutive patients with prostate adenocarcinoma, 30 were treated with HDRBT alone and 30 with IHT preceding HDRBT. Prior to catheter implantation, a 'virtual' treatment plan (VP) was complied, a 'live' plan (LP) was prepared before patient irradiation, and a 'post' plan (PP) was drawn up after completing the irradiation procedure. In each plan, based on transrectal ultrasound images, the contours of the prostate, urethra, and rectum were delineated and the respective volumes and dose-volume histogram parameters were evaluated. These parameters, established for the LP, were then compared with those of the PP., Results: Changes in prostate volume and in parameters of the treatment plans were observed, but differences between the two patient groups were not statistically significant. For all 60 patients treated, the average prostate volume in the VP was 32 cm(3), in the LP 41 cm(3), and the PP 43 cm(3). Average values of relative changes in the therapy planning parameters between LP and PP were for the prostate D90 -5.7%, V100 -5.6%, V200 -13.2%, for the urethra D0, 1 cm(3) -1.6%, and for rectum D2 cm(3) 0%., Conclusion: Hyperthermia prior to HDRBT does not significantly change the volume of the prostate and there is no need to perform the new treatment plan after the hyperthermia session.

Although Echinodermata is one of the only stenohaline phyla in the animal kingdom, several species show remarkable abilities to acclimate and survive in euryhaline habitats. The last comprehensive review of this topic was over 25 years ago and much work has been published since. These recent studies expand the field reports of species living in hyposaline environments and detail experimental research on the responses, physiological range, and limits of echinoderms to salinity challenges. I provide a brief review of the historical concepts and measures of salinity and relate this overview to the physiological and ecological studies on echinoderms. Many marine biologists are not aware that chemical oceanographers advocate abandoning today's commonly used measure of salinity, 'PSU', in favour of absolute salinity (SA)-a return to the ppt (‰) metric. The literature survey reveals only one euryhaline-tolerant species in the Southern Hemisphere (there are 42 in the North) and more euryhaline species in the geologically older, brackish seas. The green sea urchin, Strongylocentrotus droebachiensis, is one of the most tolerant echinoids to hyposalinity. Different source populations have varying levels of acclimation and tolerance to hyposalinity. Experiments show that green urchins previously unexposed to hyposalinity experience a clear decrease in growth rates; however, this adverse effect is short lived. Green urchins already acclimated to hyposalinity can endure intense and repeated bouts and grow at the same rate of urchins not exposed. Promising future work on the physiological and cellular mechanisms of hyposalinity acclimation includes comparative studies of the role of heat shock proteins in the response to changing salinities., (© 2013 Elsevier Ltd. All rights reserved.)

We assessed the influence of rock cavities, or pits, on the growth dynamics and behavior of the purple sea urchin, Strongylocentrotus purpuratus. In a paired-designed, laboratory experiment, sea urchins were assigned to sandstone blocks that were either 'Flat' or had a 'Pit' drilled into the center. At the start, both groups were approximately the same shape and size. In just 2 months, the shapes of the tests were significantly different between the two treatments, with the Pit urchins having an increased height:diameter profile. This result demonstrates the plastic nature of the sea urchin test and that, despite its apparent rigidity, it is capable of deforming during growth. In addition, the presence of pits modified behavior and food consumption as well as allometric growth of the test and Aristotle's lantern. Sea urchins on Pit sandstone blocks tended to stay in the cavities and not move about the flat areas, whereas individuals on Flat blocks changed position. Sea urchins in the Pit treatment consumed less food and had relatively larger demipyramids (the 'jaw' ossicle in Aristotle's lantern). These morphological and allometric changes occurred over a short time-period (8-20 weeks). We conclude that microhabitat is an important factor in controlling the behavior and growth dynamics of the bioeroding sea urchin S. purpuratus.

Lithium fluoride thermoluminescence (TL) detectors, with different Li composition (Li-6 and Li-7) and various activators (LiF:Mg,Ti, LiF:Mg,Cu,P), are widely used for dosimetry in space. The primary radiation field in space is composed of fast electrons, protons and heavy charged particles (HCP). By its interaction with the structures of the spacecraft, this field may be modified inside the crew cabin. Therefore, calibration of TL detectors against a dose of gamma-rays is not sufficient for relating the TL readout to absorbed dose or to quantities relevant in radiation protection, without suitable correction. We introduce and calculate the detection efficiency, eta, relative to gamma-ray dose, of lithium fluoride detectors after proton and heavy charged particle (HCP) irradiation. We calculate eta for MCP-N (LiF:Mg,Cu,P) and for MTS-N (LiF:Mg,Ti) using microdosimetric models. The microdosimetric distributions used in these models (for HCP of charges between Z=1 to Z=8 and in the energy range between 0.3 MeV/amu and 20 MeV/amu) are calculated using an analytical model, based on the results of Monte Carlo simulated charged particle tracks using the MOCA-14 code. The ratio etaMCP-N/etaMTS-N for protons of stopping power (in water) below 10 keV/microm lies in the range between 0.65 and 1.0 and for HCP with Z>1--between 0.3 and 0.6. The stopping power of the particle is found not to be a unique parameter to scale the response of TL detectors. The combination of response of LiF:Mg,Cu,P and LiF:Mg,Cu,P detectors can be more suitable for a dose correction in space radiation fields.

Bacteriophage PRD1, which infects Escherichia coli and Salmonella typhimurium, consists of an icosahedral capsid enclosing a membrane-packaged double-stranded DNA genome. The viral shell has been investigated using time and temperature resolved Raman and ultraviolet-resonance Raman spectroscopy to reveal novel features of the capsid structure and its pathway of assembly from P3 subunits. Raman spectra show that the shell is thermostable to 50 degrees C, and disassembles between 50 and 70 C degrees with only a small change in P3 conformation. However, the products of thermal disassembly depend sensitively upon total protein concentration. Characterization by analytical ultracentrifugation indicates that below 8 mg/ml, the purified shell disassembles primarily into P3 trimers; at higher concentrations, larger multimers of P3 are formed. Guanidine hydrochloride (GuHCl) dissociation of the P3 shell yields similar results. Purified P3 trimers, isolated either by heat or GuHCl treatment, exhibit structure sensitivity between 30 and 50 degrees C. Thus, shell disassembly diminishes P3 thermostability. Both the lower temperature transition (30 degrees C to 50 degrees C) of the trimer and the higher temperature transition (50 degrees C to 70 degrees C) of the shell involve a conversion of approximately 5% of the P3 peptide backbone from alpha-helix to beta-strand. Deuterium exchange of the P3 peptide backbone reveals more rapid exchange in the shell than in the trimer, consistent with the observed non-specific polymerization of trimers at high concentration. Conversely, the exchange of indole 1NH groups shows that approximately 65% of tryptophan residues are protected against exchange in the assembled shell. The results suggest a mechanism for shell assembly in which the specific association of trimers into the correct shell architecture involves stabilization of a subunit alpha-helical domain and sequestering of selected side-chains from solvent access. We propose a capsid assembly model which couples P3 shell formation with the final step in folding of the P3 subunit.

We describe an ultraviolet resonance Raman (UVRR) spectrometer appropriate for structural studies of biological macromolecules and their assemblies. Instrument design includes the following features: a continuous wave, intracavity doubled, ultraviolet laser source for excitation of the Raman spectrum; a rotating cell (or jet source) for presentation of the sample to the laser beam; a Cassegrain optic with f/1.0 aperture for collection of the Raman scattering; a quartz prism dispersing element for rejection of stray light and Rayleigh scattering; a 0.75-m single grating monochromator for dispersion of the Raman scattering; and a liquid-nitrogen-cooled, charge-coupled device for detection of the Raman photons. The performance of this instrument, assessed on the basis of the observed signal-to-noise ratios, the apparent resolution of closely spaced spectral bands, and the wide spectrometer bandpass of 2200 cm-1, is believed superior to previously described UVRR spectrometers of similar design. Performance characteristics of the instrument are demonstrated in UVRR spectra obtained from standard solvents, p-ethylphenol, which serves as a model for the tyrosine side chain, the DNA nucleotide deoxyguanosine-5'-monophosphate, and the human tumor necrosis factor binding protein, which is considered representative of soluble globular proteins.

The use of carcinoembryonic antigen was evaluated in 425 patients with a mean follow-up of 48 months. The preoperative and postoperative carcinoembryonic antigen levels were predictive of recurrence and survival independent of the tumor stage. In a multivariate regression analysis of age, location, tumor stage, and preoperative and postoperative carcinoembryonic antigen levels, the latter three factors were significant prognostic variables with respect to the adjusted survival. Recurrent disease was found in 42% of patients, excluding patients with stage IV disease. The carcinoembryonic antigen level at recurrence was greater than 5 ng/mL in 79% of the patients and in 89% of the intra-abdominal recurrences. Carcinoembryonic antigen level at recurrence was not predictive of postrecurrence survival except in the subgroup of locoregional disease. The life span in patients with liver and lung metastases was not influenced by carcinoembryonic antigen level at recurrence. Preoperative and postoperative carcinoembryonic antigen levels can indicate a poorer prognostic group of patients with colorectal cancer who may benefit from adjuvant treatment. The carcinoembryonic antigen at recurrence can be used effectively to diagnose intra-abdominal recurrences and project survival after development of local/regional disease.

Eighty-seven patients with a carcinoma in a polyp were reviewed over a 12-year period. Ten histologic criteria were analyzed for an association with the presence of residual carcinoma. Four factors were identified as having prognostic value: size greater than 1.5 cm, sessility, cancer of at least 50% of the adenoma volume, and invasive carcinoma. Polypectomy alone is adequate treatment unless the carcinoma invades deeper to the muscularis mucosa and is associated with one or more of these characteristics.

An evaluation has been made of some of the factors which may affect the efficiency of settle plates. Water loss was found to be linear with time. Although the count was reduced over an 8 h period the reduction was not statistically significant. No difference in total bacterial counts could be detected between four, 1/2 h exposures and one, 2 h exposure. The addition of water and the surface area of the plates had no effect on the total count.

Propranolol (Inderal; 1) is extensively metabolized in man. Metabolites of interest pharmacologically include ring-hydroxylated propranolols (1a-g). In order to identify these ring-oxidized products and to study the effect of hydroxyl position on biological activity, we have synthesized all seven isomers. With the exception of 1b and 1g, the desired compounds were prepared by alkylation of the respective methoxy-1-naphthols with epichlorohydrin and reaction of the resulting epoxide with isopropylamine. Cleavage og the methyl group in fused pyridine hydrochloride afforded 1a,c-f. 1g was prepared by the direct alkylation of 1,8-naphthalenediol (17) with epichlorohydrin, followed by reaction with isopropylamine. 1b was synthesized by treating 2-naphthol (9) with chlorine gas and then treating the resulting 1,1-dichloronaphthalen-2(1H)-one (10) with sodium allyl oxide. Acetylation of the hydroxy function and epoxidatrion of the allyl group, followed by relation with isopropylamine, gave 3'-hydroxy-4'-chloropropranolol (15). Dechlorination gave 1b. All of the racemic hydroxylated propranolols produced beta blockade and direct vasodilation in anesthetized dogs. The potency is strongly dependent upon the position of the hydroxyl group, i.e., 1e is 4 times as potent as 1 as a beta receptor antagonist, whereas 1a, 1b, and 1g are all significantly less potent than 1. For direct vasodilation, 1a and 1g are equipotent to 1, while 1b-f are much less potent. The potencies of the compounds were also compared with their 1-octanol/pH 7.4 buffer distribution coefficients; the direct vasodilating potency was found to increase with increasing lipophilicity, while the beta-adrenergic antagonist potency decreased.

Pyruvate kinase was purified from cat and trout muscle. The enzymes had similar amino acid compositions and subunit molecular weights. In contrast to the mammalian enzyme, the trout muscle pyruvate kinase was activated by fructose 1,6-bisphosphate. However, unlike the L-type pyruvate kinase from mammalian liver it was not phosphorylated by cyclic-AMP-dependent protein kinase. The purified enzyme from cat muscle was carboxymethylated with iodo[2-14C]acetic acid under conditions that led to the preferential labelling of one especially reactive thiol group. The labelled enzyme was cleaved with CNBr, and the radioactive fragment purified. Amino acid sequence analysis of the reactive-thiol-containing fragment from cat muscle pyruvate kinase showed it had the following sequence: Ile-Gly-Arg-[14C]CmCys-Asn-Arg-Ala-Gly-Lys-Pro-Val-Ile-CmCys-Ala-Thr-Gln- Hse. The corresponding peptide from trout pyruvate kinase had only one difference in its amino acid composition and the sequence around the reactive thiol was identical.

The intramuscular administration of L-cycloserine, gabaculine, and aminooxyacetic acid caused significant, time-dependent increases in the gamma-aminobutyric acid (GABA) content of both whole brain and synaptosomal-enriched preparations obtained from the tissue, a linear relationship being observed between the two parameters. In contrast, the administration of hydrazine resulted in a large increase in whole brain GABA level, with little change in the synaptosomal GABA content. The key factor in these different responses appeared to be the degree of inhibition of glutamic acid decarboxylase by the drugs. Pretreatment of mice with the GABA-elevating agents resulted in a delay in the onset of seizures, which was related directly to the increase in synaptosomal GABA content. Although the seizures were delayed, they occurred while the GABA content of nerve endings (synaptosomes) was above that in preparations from untreated animals. The decrease in GABA content at the onset of seizures, expressed as a percentage of the level at the time of injection of the convulsant agent, was, however, reasonably constant. A hypothesis to explain these results is proposed.

This paper describes the education of the librarians under whose care the medical libraries of Great Britain have flourished and the way junior assistants now move toward higher qualification. It expresses the hope that the changed Library Association syllabus gives the medical library assistant an earlier chance of using his knowledge of medical library practice in the papers presented; that the inclusion of medical material in the examination will encourage library schools to provide appropriate instruction in this field, thus achieving a system like that in the United States. For its encouragement of continuing education for the senior librarian, our debt is acknowledged to the Medical Section or Group of the Library Association, which through its meetings gives opportunity for cooperation and discussion of suggestions for further improvement.