Explicit and implicit category learning in categorical visual search

Categorical search has been heavily investigated over the past decade, mostly using natural categories that leave the underlying category mental representation unknown. The categorization literature offers several theoretical accounts of category mental representations. One prominent account is that separate learning systems account for classification: an explicit learning system that relies on easily verbalized rules and an implicit learning system that relies on an associatively learned (nonverbalizable) information integration strategy. The current study assessed the contributions of these separate category learning systems in the context of categorical search using simple stimuli. Participants learned to classify sinusoidal grating stimuli according to explicit or implicit categorization strategies, followed by a categorical search task using these same stimulus categories. Computational modeling determined which participants used the appropriate classification strategy during training and search, and eye movements collected during categorical search were assessed. We found that the trained categorization strategies overwhelmingly transferred to the verification (classification response) phase of search. Implicit category learning led to faster search response and shorter target dwell times relative to explicit category learning, consistent with the notion that explicit rule classification relies on a more deliberative response strategy. Participants who transferred the correct category learning strategy to the search guidance phase produced stronger search guidance (defined as the proportion of trials on which the target was the first item fixated) with evidence of greater guidance in implicit-strategy learners. This demonstrates that both implicit and explicit categorization systems contribute to categorical search and produce dissociable patterns of data.

Perceptions of social circle vaccine acceptance and COVID-19 vaccine initiation among postpriority vaccine eligible adults

OBJECTIVES

COVID-19 vaccines in the United States were made available to the general public aged 16 years and older in April 2021, but uptake in the months following was variable. We aimed to investigate this variability as a function of interpersonal factors, namely perceived social circle vaccine acceptance and proximity to illness, controlling for intrapersonal factors more often associated with vaccine behavior.

METHOD

Data come from the Understanding Coronavirus in America tracking survey (February 2021-July 2021). We estimated the probability of vaccination among those who were unvaccinated as of April 14, 2021 (N = 2,199), the day before the announcement of general public eligibility. Stratified modeling by race accounted for subgroup differences.

RESULTS

People who perceived social circle vaccine acceptance (Hazard Ratio [HR] = 1.37, p < .001), higher risk of infection (HR = 1.20, p < .001), greater trust in the vaccine (HR = 1.42, p < .001), and lower risk of vaccine side effects (HR = 0.77, p < .001) were more likely to get vaccinated. Perceptions of social circle vaccine acceptance were associated with vaccine initiation for all racial subgroups except Black respondents, for whom concerns about vaccine side effects were central.

CONCLUSIONS

Perceived social circle vaccine acceptance was associated with time to the first dose of the COVID-19 vaccine. With public uncertainty about this new vaccine, people may have relied on perceptions of peers' vaccination intentions when deciding on their own vaccination. We discuss strategies for promoting vaccine uptake by intervening on perceptions of social norms. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A Culturally Tailored Narrative Decreased Resistance to COVID-19 Vaccination Among Latinas

PURPOSE

This study tested the relative efficacy of a culturally tailored dramatic narrative promoting COVID-19 vaccination in changing attitudes and behavioral intent among unvaccinated Latinas compared to a nonnarrative control containing similar information.

DESIGN

A pretest-posttest experimental study with unvaccinated Latinas randomly assigned to watch either a dramatic narrative featuring Latina characters countering prevalent myths about COVID-19 vaccines or a nonnarrative film containing similar information (control condition).

SETTING

The experiment was hosted online with the films embedded in the survey.

PARTICIPANTS

Three-hundred-ninety adult Latinas living in the United States (mean age = 33.4 years; SD = 11.2) who had not been vaccinated against COVID-19 despite being eligible. At pretest, 57.7% were hesitant and 42.3% were resistant (refusing) to get vaccinated.

MEASURES

Self-reported measures of engagement with the film, COVID-19 vaccine attitudes, and intent to get vaccinated within 30 days at pretest and posttest.

RESULTS

Resistant women were significantly more engaged in the dramatic narrative than the nonnarrative control film (P = .03). Being engaged in a film predicted more positive post-viewing attitudes toward the vaccine (b = .28; P < .001) and higher intent to get vaccinated (b = 2.34, P < .001).

CONCLUSION

Using culturally tailored stories to promote healthy behaviors such as vaccination can be an effective way of reaching resistant audiences.

Community-Based Public Health Vaccination Campaign (VaccinateLA) in Los Angeles' Black and Latino Communities: Protocol for a Participatory Study

BACKGROUND

The COVID-19 pandemic has significantly affected Los Angeles County and disproportionately impacted Black and Latino populations who experienced disparities in rates of infection, hospitalizations, morbidity, and mortality. The University of Southern California (USC), USC Keck School of Medicine, Southern California Clinical and Translational Science Institute, USC Mann School of Pharmacy and Pharmaceutical Sciences, Annenberg School for Journalism and Communication, and Children's Hospital Los Angeles will launch a collaborative public health campaign called VaccinateLA.

OBJECTIVE

VaccinateLA will implement a community-based, community-partnered public health campaign that (1) delivers culturally tailored information about COVID-19 and available vaccines; and (2) addresses misinformation and disinformation, which serves as a barrier to vaccine uptake. The campaign will be targeted to communities in Los Angeles with the highest rates of COVID-19 infection and the lowest vaccination rates. Using these criteria, the campaign will be targeted to neighborhoods located in 34 zip codes in the Eastside and South Los Angeles. The primary aim of VaccinateLA will be to design and deliver an evidence-based multimedia public health campaign tailored for Black and Latino populations. A secondary aim will be to train and deploy community vaccine navigators to deliver COVID-19 education, help individuals overcome barriers to getting vaccinated (eg, transportation and challenges registering), and assist with delivering vaccinations in our targeted communities.

METHODS

We will use a community-based, participatory research approach to shape VaccinateLA's public health campaign to address community members' attitudes and concerns in developing campaign content. We will conduct focus groups, establish a community advisory board, and engage local leaders and stakeholders to develop and implement a broad array of educational, multimedia, and field-based activities.

RESULTS

As of February 2023, target communities have been identified. The activities will be initiated and evaluated over the course of this year-long initiative, and dissemination will occur following the completion of the project.

CONCLUSIONS

Engaging the community is vital to developing culturally tailored public health messages that will resonate with intended audiences. VaccinateLA will serve as a model for how an academic institution can quickly mobilize to address a pressing public health crisis, particularly in underrepresented and underresourced communities. Our work has important implications for future public health campaigns. By leveraging community partnerships and deploying community health workers or promotores into the community, we hope to demonstrate that urban universities can successfully partner with local communities to develop and deliver a range of culturally tailored educational, multimedia, and field-based activities, which in turn may change the course of an urgent public health crisis, such as the COVID-19 pandemic.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/40161.

Reliability and Concurrent Validity of Global Physical Activity Questionnaire (GPAQ): A Systematic Review

This study aimed to systematically review previous studies on the reliability and concurrent validity of the Global Physical Activity Questionnaire (GPAQ). A systematic literature search was conducted (n = 26) using the online EBSCOHost databases, PubMed, Web of Science, and Google Scholar up to September 2019. A previously developed coding sheet was used to collect the data. The Modified Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was employed to assess risk of bias and study quality. It was found that GPAQ was primarily revalidated in adult populations in Asian and European countries. The sample size ranged from 43 to 2657 with a wide age range (i.e., 15–79 years old). Different populations yielded inconsistent results concerning the reliability and validity of the GPAQ. Short term (i.e., one- to two-week interval) and long-term (i.e., two- to three-month apart) test–retest reliability was good to very good. The concurrent validity using accelerometers, pedometers, and physical activity (PA) log was poor to fair. The GPAQ data and accelerometer/pedometer/PA log data were not compared using the same measurements in some validation studies. Studies with more rigorous research designs are needed before any conclusions concerning the concurrent validity of GPAQ can be reached.

Comparing the profiles of UK and Australian military veterans supported by national treatment programmes for post-traumatic stress disorder (PTSD)

Introduction

The aim of this study was to compare and contrast the profiles of military veterans seeking formal support for post-traumatic stress disorder (PTSD) in national treatment programmes in Australia and the UK to better understand the needs of this vulnerable population.

Methods

Data were extracted from 1926 participants in these treatment programmes. This consisted of 1230 from the UK who had accessed support between 2014 and early 2019, and 696 from Australia who had accessed support between 2014 and 2018. Comparison was made between a number of sociodemographic characteristics (age, sex and educational achievements), military factors (branch of military, time since leaving the military and whether participants were early service leavers or not) and health outcomes (PTSD, anger, alcohol misuse, anxiety and depression).

Results

Small differences were observed, with those in the UK cohort appearing to be younger, having lower educational achievement, being more likely to be ex-Army, having longer periods of enlistment in the military and taking longer to seek help. Further, minor differences were reported in health outcomes, with those in the UK cohort reporting more severe symptoms of PTSD, anger, anxiety and depression.

Conclusions

Overall, the observed differences between the cohorts were modest, suggesting that treatment-seeking veterans from the Australian and UK cohorts reported similar presentations. This provides evidence to support the establishment of international cohorts of treatment-seeking veterans to improve knowledge within this field.

Comparative Efficacy of Intramuscular and Scarification Routes of Administration of Live Smallpox Vaccine in a Murine Challenge Model

In recent years concern has mounted regarding the possibility of a re-emergence of smallpox through biowarfare or bioterrorism. There is also concern over the incidence of human monkeypox in endemic areas and the potential for monkeypox to be accidentally transported to non-endemic areas. In the event of re-emergence of smallpox or emergence of monkeypox, the accepted route of administration for live replicating smallpox vaccine is dermal scarification, which generates a virus-shedding lesion that persists for several days at the vaccination site. The lesion is a potential source of contact transmission of vaccine to individuals who may be contra-indicated for receipt of the live vaccine. In this study, we compare dermal scarification with intramuscular vaccination for replicating smallpox vaccine in a mouse lethal challenge model. Comparisons are made over multiple vaccine and challenge doses and data recorded for lethality, disease severity, and antibody responses. Qualitative and quantitative differences between the two routes are observed, and for the intramuscular route the febrile response is not suppressed after subsequent virulent vaccinia virus challenge. However both routes generate an immune response and protect from severe disease and death. Although dermal scarification is the preferred route of vaccination for the general population, intramuscular vaccination may be an option for people who are not contraindicated for the live vaccine, but who are close contacts of people who are contraindicated for the live vaccine, in an emergency situation.

Pre- performance routines followed by free throw shooting accuracy in secondary basketball players

Study aim: The purpose of the current study was to determine whether existing pre-performance routines had an effect on free throw shooting accuracy in high school pupils as compared to shooting without a pre-performance routine.

Materials and methods: Participants were 34 freshman high school basketball players. Twenty male (n = 20) and fourteen female (n = 14) of various ethnic backgrounds were randomly assigned to a condition and were asked to implement a pre-performance routine in one condition and a non-pre-performance routine in another condition for free throw shooting. A within subjects crossover design was used to analyse the data based on a pre-performance routine and a non-pre-performance routine framework. The pre-performance routine conditions were considered the experimental conditions. A Missed-Made Shots table was used to track performance (miss-made shots) for the shots in both conditions.

Results: There were differences between the experimental condition (pre-performance routine) and the comparison condition (non-pre-performance routine) Z(22) = –4.61, p < 0.01 with the experimental condition’s median scores out-performing the comparison condition scores; however the differences were very small.

Conclusions: These findings suggest that there were differences between the experimental condition (pre-performance routine) and the comparison condition (non-pre-performance routine). Results suggest that there may be additional relevant factors in addition to pre-performance routines that should be considered in helping youth develop closed motor skills (e.g., mental imagery, physical exertion, outside factors – audience).

Comparative efficacy of replicating smallpox vaccine strains in a murine challenge model

There is currently considerable concern about the vulnerability of human populations to biowarfare or bioterrorist attacks with variola virus (VARV). Traditional smallpox vaccines were manufactured using the lymph of ruminants infected with the vaccinia virus (VACV). However, these production methods do not meet current standards for vaccines, especially since the emergence of transmissable spongiform encephalopathies in domesticated ruminants. This study has examined the protective efficacy of the Lister (Elstree) vaccine strain from various sources in a murine lethal challenge model. Considerable variation in efficacy is observed between the Lister material obtained from the American Type Culture Collection (ATCC) and the same strain obtained from vaccine stockpiles. A new, tissue-culture derived Lister vaccine is assessed against a bench-mark of multiple lots from a historical stockpile of the traditional vaccine. Apparent qualitative differences are observed between historical and new vaccines. Statistically significant differences are observed between different batches of the traditional vaccine, and the efficacy of the tissue-culture produced vaccine falls within this range.

Experimental studies on the spatiotemporal expression of WT1 and RALDH2 in the embryonic avian heart: a model for the regulation of myocardial and valvuloseptal development by epicardially derived cells (EPDCs)

Epicardially derived cells (EPDCs) delaminate from the primitive epicardium through an epithelial-to-mesenchymal transformation (EMT). After this transformation, a subpopulation of cells progressively invades myocardial and valvuloseptal tissues. The first aim of the study was to determine the tissue-specific distribution of two molecules that are thought to play a crucial function in the interaction between EPDCs and other cardiac tissues, namely the Wilms' Tumor transcription factor (WT1) and retinaldehyde-dehydrogenase2 (RALDH2). This study was performed in normal avian and in quail-to-chick chimeric embryos. It was found that EPDCs that maintain the expression of WT1 and RALDH2 initially populate the subepicardial space and subsequently invade the ventricular myocardium. As EPDCs differentiate into the smooth muscle and endothelial cell lineage of the coronary vessels, the expression of WT1 and RALDH2 becomes downregulated. This process is accompanied by the upregulation of lineage-specific markers. We also observed EPDCs that continued to express WT1 (but very little RALDH2) which did not contribute to the formation of the coronary system. A subset of these cells eventually migrates into the atrioventricular (AV) cushions, at which point they no longer express WT1. The WT1/RALDH2-negative EPDCs in the AV cushions do, however, express the smooth muscle cell marker caldesmon. The second aim of this study was to determine the impact of abnormal epicardial growth on cardiac development. Experimental delay of epicardial growth distorted normal epicardial development, reduced the number of invasive WT1/RALDH2-positive EPDCs, and provoked anomalies in the coronary vessels, the ventricular myocardium, and the AV cushions. We suggest that the proper development of ventricular myocardium is dependent on the invasion of undifferentiated, WT1-positive, retinoic acid-synthesizing EPDCs. Furthermore, we propose that an interaction between EPDCs and endocardial (derived) cells is imperative for correct development of the AV cushions.

A GATA-6 gene heart-region-specific enhancer provides a novel means to mark and probe a discrete component of the mouse cardiac conduction system

The transcriptional programs that specify the distinct components of the cardiac conduction system are poorly understood, in part due to a paucity of definitive molecular markers. In the present study we show that a cGATA-6 gene enhancer can be used to selectively express transgenes in the atrioventricular (AV) conduction system as it becomes manifest in the developing multichambered mouse heart. Furthermore, our analysis of staged cGATA-6/lacZ embryos revealed that the activity of this heart-region-specific enhancer can be traced back essentially to the outset of the cardiogenic program. We provide evidence that this enhancer reads medial/lateral and anterior/posterior positional information before the heart tube forms and we show that the activity of this enhancer becomes restricted at the heart looping stage to AV myocardial cells that induce endocardial cushion formation. We infer that a deeply-rooted heart-region-specific transcriptional program serves to coordinate AV valve placement and AV conduction system formation. Lastly, we show that cGATA-6/Cre mice can be used to delete floxed genes in the respective subsets of specialized heart cells.

Treatment of combat-related nightmares using imagery rehearsal: a pilot study

Posttraumatic nightmares are a hallmark of PTSD and distinct from general nightmares as they are often repetitive and faithful representations of the traumatic event. This paper presents data from a pilot study that examined the use of Imagery Rehearsal in treating combat-related nightmares of 12 Vietnam veterans with PTSD. Three treatment groups, comprising 4 veterans in each, completed standardised treatment across 6 sessions. Treatment effects were investigated using nightmare diaries and established instruments, including the IES-R, BDI, BAI, and SCL-90-R. The data demonstrate significant reductions in nightmares targeted, and improvements in PTSD and comorbid symptomatology. The paper recommends that, on the basis of the promising preliminary data, a randomised control trial be established to assess imagery ability and attitude toward nightmares.

Mitochondrial phosphate transport protein. Reversions of inhibitory conservative mutations identify four helices and a nonhelix protein segment with transmembrane interactions and Asp39, Glu137, and Ser158 as nonessential for transport

The mitochondrial phosphate transport protein (PTP) has six (A--F) transmembrane (TM) helices per subunit of functional homodimer with all mutations referring to the subunit of the homodimer. In earlier studies, conservative replacements of several residues located either at the matrix end (Asp39/helix A, Glu137/helix C, Asp236/helix E) or at the membrane center (His32/helix A, Glu136/helix C) of TM helices yielded inactive single mutation PTPs. Some of these residues were suggested to act as phosphate ligands or as part of the proton cotransport path. We now show that the mutation Ser158Thr, not part of a TM helix but located near the center of the matrix loop (Ile141--Ser171) between TM helices C and D, inactivates PTP and is thus also functionally relevant. On the other side of the membrane, the single mutation Glu192Asp at the intermembrane space end of TM helix D yields a PTP with 33% wild-type activity. We constructed double mutants by adding this mutation to the six transport-inactivating mutations. Transport was detected only in those with Asp39Asn, Glu137Gln, or Ser158Thr. We conclude that TM helix D can interact with TM helices A and C and matrix loop Ile141--Ser171 and that Asp39, Glu137, and Ser158 are not essential for phosphate transport. Since our results are consistent with residues present in all 12 functionally identified members of the mitochondrial transport protein (MTP) family, they lead to a general rule that specifies MTP residue types at 7 separate locations. The conformations of all the double mutation PTPs (except that with the matrix loop Ser158Thr) are significantly different from those of the single mutation PTPs, as indicated by their very low liposome incorporation efficiency and their requirement for less detergent (Triton X-100) to stay in solution. These dramatic conformational differences also suggest an interaction between TM helices D and E. The results are discussed in terms of TM helix movements and changes in the PTP monomer/dimer ratio.

Rotavirus VP7 epitope mapping using fragments of VP7 displayed on phages

cDNA copies of the complete porcine rotavirus CRW-8 VP7 gene were randomly digested to fragments of about 30-60 or 30-500 base pairs by DNase1 in the presence of Mn(2+). The fragments were cloned and expressed in a filamentous phage fd-tet-derived vector to create specific-gene-related peptide libraries. Polyclonal antibodies were then used to pan the SGRP libraries for antibody-binding phages. Analysis of the phage isolates revealed that the majority (86%) of them only had a single insert. However, phages displaying composite inserts containing the VP7 antigenic regions A, B, and C, originally defined by neutralising monoclonal antibody escape mutants, were also isolated. Inserts containing A or C region peptide were found to contain extra sequences from the C region, while the B region epitope was linear and had additional sequence from either upstream or downstream. In addition a dominant and possibly non-neutralising VP7 epitope was identified around amino acids 263-270. One of the recreated antigenic epitopes has also been fused to the outer membrane protein A (OmpA) of Escherichia coli and shown to maintain its antigenicity. The results in this study may have significant implication for recreation of conformational epitopes and vaccine development.

Bacterial expression of the major antigenic regions of porcine rotavirus VP7 induces a neutralizing immune response in mice

The outer capsid protein of rotavirus, VP7, is a major neutralization antigen. A chimeric protein comprising Escherichia coli (E. coli) outer membrane protein A (OmpA) and part of porcine rotavirus VP7 containing all three antigenic regions (217 amino acids) was expressed in Salmonella and E. coli as an outer-membrane associated protein. Mice immunized intraperitoneally or orally, respectively, with live E. coli or Salmonella cells expressing this chimeric protein produced antibodies against native VP7 as determined by enzyme-linked immunosorbent assays and neutralization tests. This indicates that the VP7 fragment from a porcine rotavirus which is antigenically similar to human rotavirus serotype 3, when expressed in bacteria as a chimeric protein, can form a structure resembling its native form at least in some of the major neutralization domains. These results indicate that the use of a live bacterial vector expressing rotavirus VP7 may represent a strategy for the development of vaccines against rotavirus-induced diarrhoea in infants.

College students' knowledge and attitudes about cesarean birth

BACKGROUND

Numerous clinicians and researchers have expressed concern about the necessity and potential adverse consequences of many cesarean births in the United States. The purpose of this study was to explore college students' attitudes and beliefs about cesarean section.

METHODS

One hundred two college students (66% women) completed a 20-item questionnaire that asked if they viewed cesarean delivery as a potentially negative experience, as a normal or acceptable method of childbirth, and as medically necessary, and asked about their beliefs concerning risk and prevention of cesarean birth.

RESULTS

The number of "undecided" responses in the study was striking (7.8% to 69.6% across the 20 items). In general, women and men responded similarly, although women were significantly more likely than men to say they would be profoundly disappointed if their babies had to be delivered by cesarean section. Despite expressing cynicism about the cesarean birth rate (40% agreed that many unnecessary cesarean births occurred) and not viewing the procedure as a normal way of giving birth (47%), most respondents (over 70%) disagreed that giving birth by cesarean would be a negative experience or would make a woman feel like a failure.

CONCLUSION

A high level of uncertainty exists about certain aspects of cesarean birth among young women and men, highlighting the need for information for prospective parents. Most college students did not view the cesarean birth experience as either potentially negative or normal. Future research should explore coverage of cesarean birth in childbirth education classes and the roles physicians, nurses, and midwives play in preparing expectant parents for the possibility of cesarean delivery.

Periplasmic expression of part of the major rotavirus capsid protein VP7 containing all the three antigenic regions in Escherichia coli

Part of the porcine rotavirus outer capsid protein VP7 containing all the three antigenic regions was expressed as a chimeric protein with bacterial alkaline phosphatase (AP) in E. coli. The construct contains an ompF promoter, the DNA encoding the signal sequence and the first 12 amino acids of mature OmpF, part of vp7 and the DNA encoding mature AP. The chimeric protein is stable, retains the biological property of AP and ability to react with polyclonal antiserum against the virus, and can be exported through the bacterial inner membrane into the periplasm.

Mitochondrial phosphate transport protein. replacements of glutamic, aspartic, and histidine residues affect transport and protein conformation and point to a coupled proton transport path

The homodimeric mitochondrial phosphate transport protein (PTP), which has six transmembrane helices per subunit, catalyzes inorganic phosphate transport in an electroneutral and pH gradient-dependent manner across the inner membrane. We have replaced the Glu, Asp, and His residues of the yeast PTP to assess their role in the transport mechanism. Mutants with physiologically relevant transport activity were identified by their ability to rescue the PTP null mutant yeast from glycerol medium. Five residues appear critical for transport: His-32 in helix A, Glu-126 and -137 in helix C, and Asp-39 and -236 at the matrix ends of helices A and E. These mutant PTPs are expressed at near normal levels in yeast. This yeast PTP and the mutants were expressed in Escherichia coli as inclusion bodies, solubilized, purified, and reconstituted. Their transport activities correlate well with the physiological assays. None of the transport inactivating mutations appear to be due to major protein conformation changes as assayed by the efficiency of PTP incorporation into liposomes. Only the Glu95Gln (cytosolic helices B and C-connecting segment), Glu163Gln and Glu164Gln (matrix helices C and D-connecting segment), and Glu126Asp (helix C) show a near 70% decrease in liposome incorporation efficiency. In addition, mutations at either end of helix D increase phosphate transport 2-fold. We would like to suggest that Glu-126, His-32, and Glu-137 (similar to Asp-96, Lys-216, and Asp-85 of bacteriorhodopsin) form a proton cotransport pathway that is coupled in an as yet undefined manner (possibly via His-32) to a phosphate transport pathway, which may include helix D.

Solvent vapor abuse leukoencephalopathy. Comparison to adrenoleukodystrophy

Chronic organic solvent vapor inhalation can cause permanent damage to the central nervous system. Clinical features and radiologic abnormalities are well known, but pathology has not been definitely established. This study describes the gross, microscopic and ultrastructural changes and fatty acid composition of cholesterol esters in the brain of two chronic paint sniffers as well as the electron microscopic findings from a third, all with permanent neurological impairment. The abnormalities which were the same in all cases consisted of a demyelinating process which grossly manifested itself as brain atrophy and subtle discoloration of the cerebral and cerebellar white matter. Periodic acid-Schiff-positive macrophages in the absence of foamy macrophages were the histological hallmark of this process. Electron microscopy revealed oval membrane-bound cytoplasmic bodies filled with bundles of trilaminar inclusions composed of 3 nm paired dense leaflets separated by a space 3-7 nm wide in macrophages. Biochemical analysis showed an increase of very long chain fatty acids in the white matter cholesterol esters. This study defines the morphologic substrate of solvent vapor abuse leukoencephalopathy. The novel ultrastructural observations in conjunction with biochemical findings provide a link with adrenoleukodystrophy and raise the possibility of similar mechanisms of myelin degradation in both.

Solitary congenital indeterminate cell histiocytoma

BACKGROUND

Indeterminate cell proliferations are rarely described in the literature. We present a case of a patient who presented at birth with a solitary lesion that spontaneously regressed.

OBSERVATIONS

Five cases of indeterminate cell proliferations have been described in the literature. Their clinical patterns display some common features including adult onset, usually with multiple lesions and a relatively benign clinical course. This patient presented at birth with a single lesion and spontaneous regression, as one would expect with congenital self-healing reticulohistiocytosis. Biopsy confirmed a dermal histiocytic nodule that was predominantly CD1 and S100 positive. Unlike patients with congenital self-healing reticulohistiocytosis, however, electron microscopy failed to demonstrate Birbeck granules.

CONCLUSION

Indeterminate cell proliferations are a distinct entity. This presentation expands the range of clinical manifestations reported. It also suggests a close relationship between indeterminate cells and Langerhans cells.

Mitochondrial phosphate transport. The Saccharomyces cerevisiae (threonine 43 to cysteine) mutant protein explicitly identifies transport with genomic sequence

The yeast mitochondrial phosphate transport protein (PTP) has only 38% sequence similarity to the bovine heart protein, and it has recently been postulated to code for a mitochondrial import receptor. Since the reconstitutively active protein is not completely pure, it is important to demonstrate explicitly that the yeast gene codes for PTP. We have replaced Thr43 with Cys (T43C) and show that its unidirectional and pH gradient-dependent inorganic phosphate transport activity becomes highly sensitive to N-ethylmaleimide. This new PTP/T43C catalyzes less than 10% of the wild type transport activity (1 mM [Pi]e, pHe (6.80); 0 mM [Pi]i, pHi (8.07); 30 s [Pi] uptake) suggesting that Thr43 occupies an important position in the PTP.

Cloning and characterization of the mitochondrial phosphate transport protein gene from the yeast Saccharomyces cerevisiae

We have cloned the gene of the Saccharomyces cerevisiae phosphate transport protein (PTP), a member of the mitochondrial anion transport protein gene family. As PTP has a blocked N-terminus, we prepared three peptides. Oligonucleotides, based on their sequences, were used to screen a Yep24-housed genomic library. A total of 2073 bases of clone Y22 code for a 311 amino acid protein (Mr 32,814), which has similarities to the anion transport proteins: a triplicate gene structure and 6 hydrophobic segments. Typical for PTP, the triplicate gene structure possesses the X-Pro-X-(Asp/Glu)-X-X-(Lys/Arg)-X-(Arg/Lys)-X (X is an unspecified amino acid) motif and the very high homology only between the first and second repeat. The 6 hydrophobic segments harbor most of the 116 amino acids that are conserved between the yeast and the beef proteins. An N-terminal-extended signal sequence, as found in the beef protein, is absent. The yeast protein has about 33% fewer basic and acidic amino acids and five fewer Cys residues than the beef protein. The protein is insensitive to N-ethylmaleimide since Cys-42 (beef) has been replaced with a Thr. Mersalyl sensitivity has been retained and must be due to one of its three cysteines. Among these three cysteines, only Cys-28, located in the first hydrophobic segment, is conserved between the yeast and the beef protein.

Study of IgG sub-class antibodies in patients with milk intolerance

An ELISA was applied to measure IgG sub-class antibodies to cow's milk beta-lactoglobulin (BLG), alpha-lactalbumin (ALA) and alpha-casein (AC) and to hen's egg ovalbumin (OA) in the sera of nineteen adult patients with milk intolerance causing either asthma, eczema or both. Results were compared with those of forty blood donors and twenty adult patients with either asthma or eczema due to inhalant allergy. Apart from one blood donor, high titres of IgG sub-class antibodies to all three milk proteins were found only in the milk intolerance group. The most frequently detected antibody was AC-specific IgG4; being high (i.e. greater than 9.98 micrograms/ml) in eight milk intolerance cases: six with eczema, one with asthma and one with both. A variable proportion of these eight patients also had high levels of IgG1, IgG2 and IgG3 antibodies to AC and IgG1, IgG2, IgG3 and IgG4 antibodies to BLG and ALA. In contrast, IgG antibody to the egg protein, OA, was remarkably restricted to IgG4 and was present in high titres in 68.4% of milk intolerant patients, 60% of inhalant allergy patients and 30% of blood donors. However, the greater incidence of high titres of IgG4 antibody to OA, compared to AC, was due to the superior coating efficiency of OA resulting in a more sensitive assay. We conclude that some adult cases of milk intolerance, particularly those with eczema, can be diagnosed by detecting raised serum levels of IgG sub-class antibodies to milk proteins.

Detection of an IgM antiglobulin in the sera of atopic patients using insolubilized IgG4, and its capacity to release histamine from leucocytes

ELISA plates coated with highly pure IgG4 were employed to detect IgM antiglobulin in atopic sera. The use of IgG4, rather than whole IgG, on the solid-phase was to provide direct evidence for the IgG4 reactivity of the antiglobulin. Bound IgM was shown to be antiglobulin in that binding can be inhibited by pre-absorption of serum with IgG. Some 75% of asthmatic patients and 29% of eczema patients were found to have significantly raised level of IgM antiglobulin. This antiglobulin resembles rheumatoid factor in that it appears to be directed against antigenic determinants common to human and rabbit IgG. Isolated antiglobulin-enriched IgM fractions released histamine from leucocytes of 7 out of 12 atopic patients. The histamine-releasing capacity of the IgM antiglobulin was shown to be operating via basophil-bound IgG in that the process can be blocked by pre-absorption of the antiglobulin with IgG. Furthermore, heating the antiglobulin-enriched IgM fraction did not affect its histamine-releasing capacity. We conclude that the IgM antiglobulin detectable in our atopic patients may contribute to the pathological changes in them.

IgE and IgG4 antibodies to bovine milk fat globule membrane in atopic eczema patients: a study of their occurrence, relevance and antigenic specificity

IgE and IgG4 antibodies to bovine milk fat globule membrane (FGM) were measured in atopic eczema patients to determine whether their presence would account for allergy to milk in cases where whole or individual milk protein-specific antibodies are not detectable. The study demonstrates that the measurements of IgE and IgG4 antibodies to FGM do not offer any additional diagnostic value in milk exacerbated cases of atopic eczema. Furthermore, cross-inhibition studies with four milk proteins showed that these FGM-reactive IgE and IgG4 antibodies are directed against alpha-casein.