Current literature and imaging techniques of aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL).

Aseptic lymphocyte-dominated vasculitis-associated lesions (ALVAL) are a recognized complication of metal-on-metal bearing hip prostheses. There is an impending concern regarding the future investigation and management of patients who have received such implants. The current literature is discussed, and the current guidelines for management of these patients in the UK are reviewed. The various imaging techniques available, such as computed tomography, metal artefact reduction magnetic resonance imaging, and ultrasound are discussed and evaluated with respect to the assessment of patients with suspected ALVAL. The histopathological findings are discussed with images of the tissue changes provided. Images of the radiological findings are also provided for all general radiological methods. ALVAL and its radiological presentation is an important issue that unfortunately may become a significant clinical problem.

When the individual comes into play: The role of self and the partner in the dyadic play fighting of rats.

Social play in rats is rewarding and important for the development of brain and social skills. There are differences in the amount of play behavior displayed among individuals, with earlier studies suggesting that, despite variation across trials, individual differences tend to be consistent. In the present study, juvenile Lister-hooded rats were paired with a different, unfamiliar same-sex partner on three days and based on the amount of play each individual initiated, it was characterized as a high, medium or low player. Using this categorization, we explored three features related to individual differences. First, we show that by increasing the number of test days from two, as was done in a previous study (Lesscher et al., 2021), to three, characterization was effectively improved. Secondly, while the earlier study only used males, the present study showed that both sexes exhibit a similar pattern of individual differences in the degree of playfulness. Even though low players consistently initiated less play than medium and high players, all rats varied in how much play they initiated from one trial to the next. Thirdly, we assessed two potential mechanisms by which the playfulness of one rat can modify the level of playfulness of the other rat (i.e., emotional contagion vs homeostasis). Analyses of individuals' contribution to the play of dyads suggest that rats consistently adjust their play behavior depending on the behavior displayed by the partner. Since this adjustment can be positive or negative, our data support a homeostatic mechanism, whereby individuals increase or decrease the amount of play they initiate, which results in the experience of an overall stable pattern of play across trials. Future research will investigate the neural bases for individual differences in play and how rats maintain a preferred level of play.

Who's laughing? Play, tickling and ultrasonic vocalizations in rats.

Social play in rats is a highly rewarding, energetic form of social interaction and important for development of the brain and social skills. The 50 kHz ultrasonic vocalizations (USV) emitted during social play are thought to be an expression of a positive affective state (laughter), which in some situations may also function as communication signals. Heterospecific play, 'tickling' by an experimenter, is thought to simulate conspecific play, and has been used to improve welfare and to study the neurobiology of positive affect. Given that tickling evokes substantial amounts of USV, we investigated whether heterospecific play is simulating conspecific play by comparing USV-behaviour associations in both contexts. If the 50 kHz calls are merely an expression of 'laughter' then the pattern and type of emission in both contexts should be similar. By contrast, as playing with a conspecific involves a two-way exchange of signalling, the additional demands on communication should lead to a different pattern of calling. While calling was prevalent in both types of play, how the different types of 50 kHz calls are used in the two contexts differed markedly. The findings suggest that while conspecific and heterospecific play are positive experiences, tickling is not the equivalent of conspecific play. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.

Measuring Play Fighting in Rats: A Multilayered Approach.

Rough-and-tumble play or play fighting is an important experience in the juvenile period of many species of mammals, as it facilitates the development of social skills, and for some species, play fighting is retained into adulthood as a tool for assessing and managing social relationships. Laboratory rats have been a model species for studying the neurobiology of play fighting and its key developmental and social functions. However, play fighting interactions are complex, involving competition and cooperation; therefore, no single measure to quantify this behavior is able to capture all its facets. Therefore, in this paper, we present a multilayered framework for scoring all the relevant facets of play that can be affected by experimental manipulations and the logic of how to match what is measured with the question being asked. © 2022 Wiley Periodicals LLC.

Adaptive Value Normalization in the Prefrontal Cortex Is Reduced by Memory Load.

Adaptation facilitates neural representation of a wide range of diverse inputs, including reward values. Adaptive value coding typically relies on contextual information either obtained from the environment or retrieved from and maintained in memory. However, it is unknown whether having to retrieve and maintain context information modulates the brain's capacity for value adaptation. To address this issue, we measured hemodynamic responses of the prefrontal cortex (PFC) in two studies on risky decision-making. In each trial, healthy human subjects chose between a risky and a safe alternative; half of the participants had to remember the risky alternatives, whereas for the other half they were presented visually. The value of safe alternatives varied across trials. PFC responses adapted to contextual risk information, with steeper coding of safe alternative value in lower-risk contexts. Importantly, this adaptation depended on working memory load, such that response functions relating PFC activity to safe values were steeper with presented versus remembered risk. An independent second study replicated the findings of the first study and showed that similar slope reductions also arose when memory maintenance demands were increased with a secondary working memory task. Formal model comparison showed that a divisive normalization model fitted effects of both risk context and working memory demands on PFC activity better than alternative models of value adaptation, and revealed that reduced suppression of background activity was the critical parameter impairing normalization with increased memory maintenance demand. Our findings suggest that mnemonic processes can constrain normalization of neural value representations.

Sucralfate and soluble sucrose octasulfate bind and stabilize acidic fibroblast growth factor.

The actions of the anti-ulcer drug sucralfate have been proposed to be mediated through interaction with fibroblast growth factors (Folkman, J., Szabo, S., Strovroff, M., McNeil, P., Li, W. and Shing, Y. (1991) Ann. Surg. 214, 414-427). We show here that acidic fibroblast growth factor (aFGF; FGF-1) binds in vitro to both the soluble potassium salt and the insoluble aluminum salt of sucrose octasulfate, as demonstrated by a variety of biophysical techniques. Similar to the well-described interaction and stabilization of aFGF by heparin, soluble sucrose octasulfate (SOS) stabilizes aFGF against thermal, urea and acidic pH-induced unfolding as determined by a combination of circular dichroism, fluorescence spectroscopy and differential scanning calorimetry. In addition, SOS also enhances the mitogenic activity of aFGF and partially protects the protein's three cysteine residues from copper-catalyzed oxidation. SOS competes with heparin and suramin for the aFGF polyanion binding site as measured by both fluorescence and light scattering based competitive binding assays. Front-face fluorescence measurements show that the native, folded form of aFGF binds to the insoluble aluminum salt of sucrose octasulfate (sucralfate). Moreover, sucralfate stabilizes aFGF against thermal and acidic pH-induced unfolding to the same extent as observed with SOS. Thus, due to their high charge density, SOS and sucralfate bind and stabilize aFGF via interaction with the aFGF polyanion binding site.

Perforation of gastrointestinal tract by poorly conspicuous ingested foreign bodies: radiological diagnosis.

Perforation of gastrointestinal (GI) tract by ingested bone fragments, toothpicks and dentures is rare but remains an important life-threatening condition, and the outcomes are poorer when the diagnosis is delayed. Invariably, clinical and radiographic diagnosis is difficult as most patients will have no recollection of ingesting a foreign body, whereas these subtle objects are often not visible on radiographs. In search for the diagnosis, CT is the modality of choice, but ultrasound imaging may be first requested in patients presenting with symptoms of acute appendicitis, cholecystitis, pyelonephritis or pelvic inflammatory disease when an ingested foreign body is not considered. Although ultrasound has limited value in depicting a foreign body, it can frequently uncover secondary signs of perforation. However, the rarity of this condition combined with non-specific clinical presentation and the propensity of these small perforating objects to be subtle makes establishing the correct diagnosis by the radiologist challenging. Therefore, understanding of the appearances of GI perforation seen on CT images or general abdominal ultrasound will aid the radiologist in the diagnosis of this important yet often unsuspected condition. This will lead to earlier diagnosis and surgical management. In this article, we illustrate the spectrum of CT, radiographic and ultrasound imaging features seen in GI perforation caused by swallowed bone fragments, toothpicks, cocktail sticks and dentures.

Structure of synthetic peptide analogues of an eggshell protein of Schistosoma mansoni.

The peptide (Gly-L-Tyr-L-Asp-L-Lys-L-Tyr)6, referred to as F4-6, was synthesized as a model for a schistosome eggshell protein in which the Gly-Tyr-Asp-Lys-Tyr consensus sequence is repeated over 40 times. Analysis by CD, Fourier transform infrared spectroscopy, potentiometric and spectrophotomertric titrations, NMR, and molecular modeling suggests that F4-6 forms some type of left-handed structure. A likely possibility appears to be a left-handed alpha-helix stabilized by Lysi-Aspi +4 salt bridges and possibly Aspi-Tyri +4 hydrogen bonding and Tyr-Tyr interactions. Spectroscopic studies of a number of F4-6 analogues support this conclusion. For example, substitution of D-Ala for Gly produces a peptide with enhanced left-handed helical spectral characteristics, whereas an L-Ala substitution results in a peptide with minimal structure. These studies suggest that the F4 protein from Schistosoma mansoni may be the first example of a naturally occurring protein devoid of proline and carbohydrate that forms a left-handed helix composed of L-amino acids, although alternative forms of other left-handed structures have yet to be rigorously excluded.

Intermittent Cushing's disease.

Described here is a young woman with intermittent Cushing's disease associated with psychotic disturbance. On five occasions, over a period of four years, she became severely depressed and had acne, amenorrhea, hirsuties and moon facies. On each of the first four occasions the symptoms lasted from two to three months and disappeared spontaneously. Biochemical investigations, including plasma ACTH estimations during the last two episodes, indicated that the adrenocortical overactivity was pituitary-dependent. During the fifth relapse the patient experienced a very severe, depressive psychosis, necessitating bilateral adrenalectomy, which resulted in complete remission.

Formulation, stability, and delivery of live attenuated vaccines for human use.

The successful use of live attenuated viral and bacterial vaccines depends not only on the proper choice and delivery of the microorganisms, but also on maintaining the sufficient potency required for an immune response. The inherent lability of live organisms presents a particular formulation challenge in terms of stabilizing and preserving vaccine viability during manufacturing, storage, and administration. This review examines pharmaceutical approaches to the stabilization, formulation, and lyophilization of biological macromolecules in general, as well as the specific applicability of these principles to live attenuated viral and bacterial vaccines. Several formulation development case studies with live vaccines are presented. In addition, comparative stability data are summarized for many other live viral and bacterial preparations. Various pharmaceutical issues with conventional and novel delivery systems for administration of parenteral and oral live vaccines are also discussed.

Developmental rearrangements of cortical glutamate-NMDA receptor binding sites in late human gestation.

NMDA-preferring glutamate receptor biding sites were characterized using the site-selective ligand [3H]MK801, in synaptic membranes prepared from cerebral cortex tissue obtained postmortem from human infants who had died with minimal neurological and neuropathological impairment between 22 and 42 weeks' gestation. It proved necessary to modify the assay protocol used with adult tissue before reliable data could be obtained. In the four cortical region studied (prefrontal, motor, occipital, temporal), [3H]MK801 bound to a single class of sites which showed significant variations in affinity only in motor cortex. The density of [3H]MK801 binding sites (calculated at constant affinity) showed marked increases in all cortical regions over this period. The extent to which glutamate could enhance [3H]MK801 binding became significantly lower in prefrontal and motor cortex as gestation progressed, so that at term, little activation was apparent. In occipital and temporal cortex, this parameter was low throughout late gestation. The evidence suggests that Glutamate-NMDA binding sites may undergo structural rearrangements which alter their ability to interact with ligands during the later stages of human gestation, and that such changes are regionally variable.

Early evolution and incidence of electroencephalographic abnormalities in Creutzfeldt-Jakob disease.

The clinical and EEG findings in patients in the literature with Creutzfeldt-Jakob disease (CJD) were reviewed and compared with findings in 36 patients with CJD at the Massachusetts General Hospital (MGH). Twenty-one of the 36 MGH cases had histopathology, all with findings consistent with CJD. EEGs in 18 patients studied pathologically and in 10 without pathological investigation (28 of the 36) had periodic sharp wave complexes (PSWC) at some time during the clinical course. Of the other eight patients, two had only a single EEG early in the course of the illness, four experienced unusually long clinical courses, and two never showed PSWC despite numerous EEGs. PSWC made their appearance within 12 weeks of onset of clinical symptoms in 25 of 27 in whom EEGs were done during that period. In the early stages, EEGs in 14 of 28 showed focal PSWC or amplitude asymmetries of PSWC that corresponded well with focal myoclonus or other focal neurological abnormalities. In the literature, PSWC occurred within 12 weeks of the onset of the illness in 66 of 75 patients (88%) with CJD who had comparable clinical and neuropathological findings and adequate EEG data during the first 3 months of the illness. In the approximately 10% of patients who experienced unusually long courses, PSWC occurred in only about 55%. The presence of PSWC in association with the appropriate clinical, biochemical, cerebrospinal fluid, and neuroradiological findings is diagnostic of CJD. Brain biopsy is, therefore, unnecessary even when clinical therapeutic trials are undertaken and certainty of diagnosis is required. The absence of PSWC in the EEG after 12 weeks' duration of illness is a point strongly against the diagnosis of CJD unless it is a rare subtype of long duration. Only those patients without PSWC need to be biopsied.

Adenine quantitation in yeast extracts and fermentation media and its relationship to protein expression and cell growth in adenine auxotrophs of Saccharomyces cerevisiae.

We have described a method to reliably measure the free adenine content of yeast extract powders or the adenine concentrations found in chemically-defined and complex fermentation samples. This method relies on the selective precolumn derivatization of adenine with chloroacetaldehyde to form the fluorescent adenine adduct 1,N6-ethenoadenine. The derivatized adenine can then be resolved from other components found in samples with reverse phase HPLC and selectively monitored with fluorescence. This method was then used to study the adenine nutritional requirements of adenine auxotrophs of recombinant Saccharomyces cerevisiae. The adenine content of individual yeast extract powders was examined in relation to the cell mass (dry cell weight, DCW) achieved in culture media formulated with these powders. A general increase in DCW was observed with increasing adenine concentration in the yeast extract. Conversely, we observed that as adenine concentration increased in complex media the expression levels of a heterologous protein decreased. This method also allowed us to examine the adenine/DCW ratio in both steady-state continuous culture and batch culture. In both cases, the total in vivo adenine content as measured by the amount of adenine utilized from the culture media was estimated to be ca. 25-40 mg/g DCW. However, data suggest that this value is in excess of what is strictly required for cell growth and represents the quantity of adenine required to saturate intracellular pools of adenine or adenine metabolites. A minimum requirement for cell growth is at least as low as 12.5 mg of adenine/g of cells.

Size and conformational stability of the hepatitis A virus used to prepare VAQTA, a highly purified inactivated vaccine.

A variety of biophysical techniques have been employed to examine the size and conformational integrity of highly purified hepatitis A virus (HAV) in solution (purified HAV particles are subsequently formalin-inactivated and adsorbed to aluminum salts for use as the vaccine VAQTA). The size of HAV particles was assessed by a combination of electron microscopy, sedimentation velocity, and dynamic light scattering. The effect of ionic strength and temperature on the overall conformational stability of HAV was determined by a combination of intrinsic HAV protein fluorescence, fluorescent probes of both RNA and protein, and UV-visible spectroscopy. A major structural change in HAV occurs near 60 degrees C with the addition of 0.2 M magnesium chloride enhancing the thermal stability of HAV by approximately 10 degrees C. Salt concentrations above 0.2 M, however, decrease the solubility of HAV. The effect of pH on the physical properties of HAV particles was monitored by dynamic light scattering, analytical size exclusion HPLC, and interaction with fluorescent dyes. HAV particles undergo a substantially reversible association/aggregation at pH values below 6 with the concomitant exposure of previously buried hydrophobic surfaces below pH 4. These results are in good agreement with previous studies of HAV thermal stability under extreme conditions in which the irreversible inactivation of the viral particles was measured primarily by the loss of viral infectivity. The wide variety of biophysical measurements described in this work, however, directly monitor structural changes as they occur, thus providing a molecular basis with which to monitor HAV stability during purification and storage.

Enhancing the avidity of a human recombinant anti-HIV-1 monoclonal antibody through oligomerization.

The oligomerization by chemical cross-linking of a recombinant human antiviral monoclonal antibody (MAb), r447-1, and its characterization are described. This MAb binds to an epitope residing in the hypervariable V3 region of the envelope protein (gp120/160) of HIV-1. A dimeric form of this MAb displays enhanced avidity and was found to be capable of neutralizing a greater variety of lymphoid cell culture-adapted HIV-1 variants and HIV-1 primary isolates than its monomeric form. The superior binding and breadth of reactivity of this antibody suggests it may have utility as a therapeutic and/or prophylactic agent, if it possesses an appropriate safety and immunogenicity profile.

Regional development of glutamate-N-methyl-D-aspartate receptor sites in asphyxiated newborn infants.

The N-methyl-D-aspartate (NMDA) subclass of glutamate receptors was examined in newborn infants dying between 25 weeks' gestation and term, either from acute cerebral hypoxia, or from other noncerebral conditions incompatible with life. Frontal, occipital, temporal, and motor cortex tissue samples were obtained at autopsy (post mortem delay: median, 45.9 hr; range, 24-96 hr) and frozen for subsequent [3H]MK801 homogenate binding assays. Whereas no significant variation was observed in ligand affinity (KD), in all cases receptor density (BMAX) increased with gestational age, in occipital cortex (27 weeks, BMAX = 222 +/- 44 fmol x mg protein(-1); 39 weeks, 439 +/- 42 fmol x mg protein[-1]), but not in motor or temporal cortex. The gestational-age increase also occurred in control frontal cortex (27 weeks, 284 +/- 80; 39 weeks, 567 +/- 40 fmol x mg protein[-1]), but was significantly less marked in frontal cortex in hypoxia cases (27 weeks, 226 +/- 90; 39 weeks, 326 +/- 47 fmol x mg protein[-1]). In all cortical areas except temporal, the maximal response to glutamate did not vary across case groups. Hypoxia cases showed an increased response to glutamate enhancement selectively in temporal cortex. Binding site density did not correlate with degree of hypoxia as assessed pathologically, suggesting that receptor differences preceded the hypoxic episode. Regional differences in glutamate-NMDA receptor sites may underlie increased vulnerability to hypoxia at birth.

The development and cross-validation of methods based on radioimmunoassay and LC/MS-MS for the quantification of the class III antiarrhythmic agent, MK-0499, in human plasma and urine.

An analytical method based on radioimmunoassay (RIA) has been developed for the determination of the antiarrhythmic agent, MK-0499, in plasma and urine. Owing to the potency of the drug, the specificity of this assay in human plasma could not be adequately determined using conventional RIA procedures. A highly specific procedure, based on LC/MS-MS, was developed to cross-validate the RIA. The lower quantifiable limits of the RIA and LC/MS-MS-based methods were 0.05 and 0.013 ng ml-1, respectively. Cross-validation data, compared using paired student's t-test regression analysis, showed excellent correlation between methods. The mass spectrometric assay was also used to simultaneously measure plasma concentrations of unlabeled and 14C-labeled MK-0499 following administration of the drug at high specific activity to volunteers.

Nonreamed nailing of tibial diaphyseal fractures in blunt polytrauma patients.

The efficacy of nonreamed nailing as the treatment of choice of unstable blunt tibial diaphyseal fractures was studied. From March 1, 1990, through August 31, 1991, 72 patients with 74 fractures that required fixation were treated. One patient died and six were lost to follow-up, leaving 65 patients with 67 fractures. Follow-up averaged 21 months (range 5-43). Fisher's exact and logistic regression analyses were used to compare grades of open fractures, comminution as classified by Winquist, and dynamic and static nailings. The failure rates of 51 titanium and 16 stainless steel nails were compared. Times to union were compared by the log rank statistic method. The average time to union was 32 weeks with 26 (39%) additional operations required to achieve union; 13 dynamizations (12 successful), 12 exchange nailings (11 successful), and one plate and bone graft. The rate of reconstructive procedures to achieve union was a more sensitive indicator of difficulties achieving union than was time to union. Reoperation rates were 33% for closed or grade I and II fractures compared with 46% for grade III fractures (NS). Among closed grade I and II static versus dynamic nailing, times to union were 36 versus 25 weeks (p < 0.01), and the reoperation rates were 44% versus 13% (p < 0.04). Winquist I and II fractures required a 24% reoperation rate versus 53% for grade III and IV and segmental fractures (p < 0.01). Static locked fractures required a 48% reoperation rate versus 12% for dynamic locked fractures (p < 0.01). A logistic regression analysis demonstrated that locking mode was the most important factor in determining reoperation rates. Fifteen additional reoperations for infection, broken or painful implants, or to remodel bones that united with an incomplete circumference of cortex were performed. With an additional 12 elective nail removals, the total reoperations numbered 53 (79%). Titanium alloy nails had a 2% failure rate versus 25% for stainless steel nails (p < 0.01). Two of 28 (7%) grade III fractures became infected. All fractures united within 10 degrees of normal alignment and 1 cm of length. Nine (13%) united with an incomplete cortical circumference, refractory to dynamization and full weight bearing. Thirteen of the 58 (22%) fractures available for an evaluation of ankle motion were symptomatic, with < 10 degrees of dorsiflexion.(ABSTRACT TRUNCATED AT 400 WORDS)

Femur fractures with femoral or popliteal artery injuries in blunt trauma.

The treatment and results of 13 blunt femoral fractures with an arterial injury were reviewed. Two of the 13 patients (15%) sustained segmental (two levels) arterial injuries. Stabilization of the femur fractures were performed before arterial repair in 10 of the 13 femurs. The results were determined at an average of 4.5 years. For the eight open fractures, two patients had above-knee amputations, no limb regained > 90 degrees of knee motion, four patients required a brace or cane, and three patients have intermittent wound drainage. The five closed fractures all regained full function with full knee motion. Due to the 15% incidence of segmental arterial injury, "wide-field" arteriography is advised for the evaluation of this injury. Femoral stabilization may be performed before arterial repair if the procedure does not encroach on the viability of the limb. The functional results depend on the soft-tissue damage, as illustrated by the poor results seen in open fractures.

Tibial diaphyseal nonunions after external fixation treated with nonreamed solid core nails.

Twenty-nine patients with tibial diaphyseal fractures had external fixators applied to treat their initial fractures and underwent nonreamed solid core nailing for nonunion (> 22 weeks). Fifteen Alta, 11 Lottes, and 3 Rush nails were used. The original fracture grades were: 1 closed, 1 grade I, 7 grade II, 3 grade IIIA, and 17 grade IIIB. The duration of nonunion was 51 weeks (average: 22 to 173). The average duration of external fixation was 19 weeks (range: 9 to 47). The average interval from fixator removal to nail was 32 weeks (range: 0 to 156). Twenty-eight patients were seen at > 12 months' follow up (average: 35; range: 10 to 58) and completion of treatment. Twenty-seven patients' fractures united at an average of 14 weeks (range: 6 to 40). One patient required a reamed exchange nailing at 39 weeks and united 58 weeks post-exchange nailing. One patient had a persistent asymptomatic nonunion. One patient developed a stress fracture 49 months post nail requiring an exchange nailing. Eleven fractures had a pre-nail deformity of 10 degrees or more; 9 were corrected. Eight patients had pre-nail wound and five had pre-nail pin tract infections. Except for two cases, all of these infections were treated successfully with surgical debridement and/or antibiotics prior to nail insertion. Two patients had their nail inserted through active infections that could not be controlled with an unstable fracture. One patient healed uneventfully in 6 weeks. One required two subsequent debridements. There were no other infections. The authors conclude that nonreamed solid core nailing is an acceptable treatment for tibial diaphyseal nonunions following external fixation.