Benralizumab: A novel treatment for the cutaneous features of paediatric eosinophilic granulomatosis with polyangiitis (pEGPA)

Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic vasculitis presenting primarily with pulmonary and cutaneous features. The disease is typically seen in the fifth or sixth decade of life (1, 2). We report a case of EGPA in an adolescent who was successfully treated with the interleukin-5 (IL-5) receptor inhibitor, benralizumab.

Evidence For Cannabidiol Modulation of Serotonergic Transmission in a Model of Osteoarthritis via in vivo PET Imaging and Behavioral Assessment

Background

Preclinical studies indicate that cannabidiol (CBD), the primary nonaddictive component of cannabis, has a wide range of reported pharmacological effects such as analgesic and anxiolytic actions; however, the exact mechanisms of action for these effects have not been examined in chronic osteoarthritis (OA). Similar to other chronic pain syndromes, OA pain can have a significant affective component characterized by mood changes. Serotonin (5-HT) is a neurotransmitter implicated in pain, depression, and anxiety. Pain is often in comorbidity with mood and anxiety disorders in patients with OA. Since primary actions of CBD are analgesic and anxiolytic, in this first in vivo positron emission tomography (PET) imaging study, we investigate the interaction of CBD with serotonin 5-HT1A receptor via a combination of in vivo neuroimaging and behavioral studies in a well-validated OA animal model.

Methods

The first aim of this study was to evaluate the target involvement, including the evaluation of modulation by acute administration of CBD, or a specific target antagonist/agonist intervention, in control animals. The brain 5-HT1A activity/availability was assessed via in vivo dynamic PET imaging (up to 60 min) using a selective 5-HT1A radioligand ([18F]MeFWAY). Tracer bindings of 17 ROIs were evaluated based on averaged SUVR values over the last 10 min using CB as the reference region. We subsequently examined the neurochemical and behavioral alterations in OA animals (induction with monosodium iodoacetate (MIA) injection), as compared to control animals, via neuroimaging and behavioral assessment. Further, we examined the effects of repeated low-dose CBD treatment on mechanical allodynia (von Frey tests) and anxiety-like (light/dark box tests, L/D), depressive-like (forced swim tests, FST) behaviors in OA animals, as compared to after vehicle treatment.

Results

The tracer binding was significantly reduced in control animals after an acute dose of CBD administered intravenously (1.0 mg/kg, i.v.), as compared to that for baseline. This binding specificity to 5-HT1A was further confirmed by a similar reduction of tracer binding when a specific 5-HT1A antagonist WAY1006235 was used (0.3 mg/kg, i.v.). Mice subjected to the MIA-induced OA for 13-20 days showed a decreased 5-HT1A tracer binding (25% to 41%), consistent with the notion that 5-HT1A plays a role in the modulation of pain in OA. Repeated treatment with CBD administered subcutaneously (5 mg/kg/day, s.c., for 16 days after OA induction) increased 5-HT1A tracer binding, while no significant improvement was observed after vehicle. A trend of increased anxiety or depressive-like behavior in the light/dark box or forced swim tests after OA induction, and a decrease in those behaviors after repeated low-dose CBD treatment, are consistent with the anxiolytic action of CBD through 5HT1A receptor activation. There appeared to be a sex difference: females seem to be less responsive at the baseline towards pain stimuli, while being more sensitive to CBD treatment.

Conclusion

This first in vivo PET imaging study in an OA animal model has provided evidence for the interaction of CBD with the serotonin 5-HT1A receptor. Behavioral studies with more pharmacological interventions to support the target involvement are needed to further confirm these critical findings.

Cannabis-Associated Psychotic-like Experiences Are Mediated by Developmental Changes in the Parahippocampal Gyrus

OBJECTIVE

Cannabis consumption during adolescence has been reported as a risk factor for psychotic-like experiences (PLEs) and schizophrenia. However, brain developmental processes associated with cannabis-related PLEs are still poorly described.

METHOD

A total of 706 adolescents from the general population who were recruited by the IMAGEN consortium had structural magnetic resonance imaging scans at both 14 and 19 years of age. We used deformation-based morphometry to map voxelwise brain changes between the two time points, using the pairwise algorithm in SPM12b. We used an a priori region-of-interest approach focusing on the hippocampus/parahippocampus to perform voxelwise linear regressions. Lifetime cannabis consumption was assessed using the European School Survey Project on Alcohol and other Drugs (ESPAD), and PLEs were assessed with the Comprehensive Assessment Psychotic-like experiences (CAPE) tool. We first tested whether hippocampus/parahippocampus development was associated with PLEs. Then we formulated and tested an a priori simple mediation model in which uncus development mediates the association between lifetime cannabis consumption and PLEs.

RESULTS

We found that PLEs were associated with reduced expansion within a specific region of the right hippocampus/parahippocampus formation, the uncus (p = .002 at the cluster level, p = .018 at the peak level). The partial simple mediation model revealed a significant total effect from lifetime cannabis consumption to PLEs (b = 0.069, 95% CI = 0.04-0.1, p =2 × 10^-16), as well as a small yet significant, indirect effect of right uncus development (0.004; 95% CI = 0.0004-0.01, p = .026).

CONCLUSION

We show here that the uncus development is involved in the cerebral basis of PLEs in a population-based sample of healthy adolescents.

Chronic PD-1 Checkpoint Blockade Does Not Affect Cognition or Promote Tau Clearance in a Tauopathy Mouse Model

Programmed cell death protein 1 (PD-1) checkpoint blockade with an antibody has been shown to reduce amyloid-β plaques, associated pathologies and cognitive impairment in mouse models. More recently, this approach has shown effectiveness in a tauopathy mouse model to improve cognition and reduce tau lesions. Follow-up studies by other laboratories did not see similar benefits of this type of therapy in other amyloid-β plaque models. Here, we report a modest increase in locomotor activity but no effect on cognition or tau pathology, in a different more commonly used tauopathy model following a weekly treatment for 12 weeks with the same PD-1 antibody and isotype control as in the original Aβ- and tau-targeting studies. These findings indicate that further research is needed before clinical trials based on PD-1 checkpoint immune blockage are devised for tauopathies.

Neural Correlates of Failed Inhibitory Control as an Early Marker of Disordered Eating in Adolescents

BACKGROUND

Binge eating and other forms of disordered eating behavior (DEB) are associated with failed inhibitory control. This study investigated the neural correlates of failed inhibitory control as a potential biomarker for DEB.

METHODS

The study used prospective longitudinal data from the European IMAGEN study adolescent cohort. Participants completed baseline assessments (questionnaires and a brain scan [functional magnetic resonance imaging]) at 14 years of age and a follow-up assessment (questionnaires) at 16 years of age. Self-reported binge eating and/or purging were used to indicate presence of DEB. Neural correlates of failed inhibition were assessed using the stop signal task. Participants were categorized as healthy control subjects (reported no DEB at both time points), maintainers (reported DEB at both time points), recoverers (reported DEB at baseline only), and developers (reported DEB at follow-up only). Forty-three individuals per group with complete scanning data were matched on gender, age, puberty, and intelligence (N = 172).

RESULTS

At baseline, despite similar task performance, incorrectly responding to stop signals (failed inhibitory control) was associated with greater recruitment of the medial prefrontal cortex and anterior cingulate cortex in the developers compared with healthy control subjects and recoverers.

CONCLUSIONS

Greater recruitment of the medial prefrontal and anterior cingulate regions during failed inhibition accords with abnormal evaluation of errors contributing to DEB development. As this precedes symptom onset and is evident despite normal task performance, neural responses during failed inhibition may be a useful biomarker of vulnerability for DEB. This study highlights the potential value of prospective neuroimaging studies for identifying markers of illness before the emergence of behavior changes.

Clinical and dermoscopic characteristics of Merkel cell carcinoma

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive cutaneous malignancy with a high mortality rate. Diagnosis is often delayed.

OBJECTIVES

To characterize the dermoscopic features of MCC.

METHODS

Clinical and dermoscopic images of 12 biopsy-proven MCCs were analysed in a retrospective manner, with existing dermoscopic criteria being scored independently by three dermatologists.

RESULTS

The four most frequent clinical features were cherry red colour, shiny surface, sharp circumscription and nodular morphology. Significant dermoscopic features included linear irregular and polymorphous vessels, poorly focused vessels, milky pink areas, white areas, structureless areas and architectural disorder. Pigmented structures were absent from all lesions.

CONCLUSIONS

The dermoscopic features described herein help the clinician to distinguish MCC from other benign and malignant red nodules. Increasing recognition of the presenting features will facilitate earlier diagnosis of MCC and reduced mortality.

Electronic tuning and uniform superconductivity in CeCoIn5

We report a globally reversible effect of electronic tuning on the magnetic phase diagram in CeCoIn(5) driven by electron (Pt and Sn) and hole (Cd, Hg) doping. Consequently, we are able to extract the superconducting pair breaking component for hole and electron dopants with pressure and codoping studies, respectively. We find that these nominally nonmagnetic dopants have a remarkably weak pair breaking effect for a d-wave superconductor. The pair breaking is weaker for hole dopants, which induce magnetic moments, than for electron dopants. Furthermore, both Pt and Sn doping have a similar effect on superconductivity despite being on different dopant sites, arguing against the notion that superconductivity lives predominantly in the CeIn(3) planes of these materials. In addition, we shed qualitative understanding on the doping dependence with density functional theory calculations.

High impulsivity predicting vulnerability to cocaine addiction in rats: some relationship with novelty preference but not novelty reactivity, anxiety or stress

RATIONALE

Impulsivity is a vulnerability marker for drug addiction in which other behavioural traits such as anxiety and novelty seeking ('sensation seeking') are also widely present. However, inter-relationships between impulsivity, novelty seeking and anxiety traits are poorly understood.

OBJECTIVE

The objective of this paper was to investigate the contribution of novelty seeking and anxiety traits to the expression of behavioural impulsivity in rats.

METHODS

Rats were screened on the five-choice serial reaction time task (5-CSRTT) for spontaneously high impulsivity (SHI) and low impulsivity (SLI) and subsequently tested for novelty reactivity and preference, assessed by open-field locomotor activity (OF), novelty place preference (NPP), and novel object recognition (OR). Anxiety was assessed on the elevated plus maze (EPM) both prior to and following the administration of the anxiolytic drug diazepam, and by blood corticosterone levels following forced novelty exposure. Finally, the effects of diazepam on impulsivity and visual attention were assessed in SHI and SLI rats.

RESULTS

SHI rats were significantly faster to enter an open arm on the EPM and exhibited preference for novelty in the OR and NPP tests, unlike SLI rats. However, there was no dimensional relationship between impulsivity and either novelty-seeking behaviour, anxiety levels, OF activity or novelty-induced changes in blood corticosterone levels. By contrast, diazepam (0.3-3 mg/kg), whilst not significantly increasing or decreasing impulsivity in SHI and SLI rats, did reduce the contrast in impulsivity between these two groups of animals.

CONCLUSIONS

This investigation indicates that behavioural impulsivity in rats on the 5-CSRTT, which predicts vulnerability for cocaine addiction, is distinct from anxiety, novelty reactivity and novelty-induced stress responses, and thus has relevance for the aetiology of drug addiction.

Variations in maternal care in the rat as a mediating influence for the effects of environment on development

Variations in maternal care have been widely considered as a critical influence in development. In the rat, variations in maternal behavior, particularly in licking/grooming, regulate the development of endocrine, emotional and cognitive responses to stress. These studies form the basis of a potentially useful model for the study of maternal effects in mammals. In this paper we provide a detailed methodological investigation into this model of maternal behavior, providing an analysis of the frequency, temporal dynamics, and transmission of maternal licking/grooming in several large cohorts. Frequency data indicate that licking/grooming is normally distributed across dams. The peak in licking/grooming occurs in the first few days postpartum and gradually declines. Dams designated as High or Low LG mothers differ in this behavior only during the first week postpartum. Observations over Days 2 to 5 postpartum are essential for the reliable assessments of individual differences in maternal behavior. Individual differences in licking/grooming behavior are stable across multiple litters, and are not associated with differences in litter size, weaning weight of pups, or gender ratio of the litter. We also observed no significant differences in the amount of licking/grooming received by individual pups within a litter, though variation does exist. Finally, maternal licking/grooming is transmitted to female offspring, though there is considerable within-litter variation in the expression of this behavior. Overall, these findings indicate considerable, normal variations in licking/grooming in the rat that are a stable, individual characteristic of rat dams.

Fluoxetine-induced increases in open-field habituation in the olfactory bulbectomized rat depend on test aversiveness but not on anxiety

Little is known regarding the functional processes underlying the treatment efficacy of antidepressant drugs. Given the close association between stress, anxiety and depression, distinguishing the common and disparate features of these processes may contribute to our current understanding. Using the olfactory bulbectomized (OBX) rat, an animal model sensitive to a variety of antidepressant drugs, this study examined the effects of chronic fluoxetine administration on open-field behavior under different conditions of stressfulness (luminance) and compared the fluoxetine effects to those evoked by the anxiolytic lorazepam. Sham-operated and OBX rats received 21 daily injections of fluoxetine (10 mg/kg), one or seven injections of lorazepam (0.1 and 0.5 mg/kg) or vehicle prior to testing in the open field or plus maze. Time series data were collected and fit with exponential regression models to estimate behavioral reactivity, habituation and residual rate of responding. Relative to sham controls, OBX rats displayed increased locomotor activity in the high luminance open field but showed decreased activity in the lower luminance open field. Time series analysis revealed that while sham animals showed increased habituation in the high compared to lower luminance open field, OBX rats did not significantly modify their responding between the two conditions. Chronic fluoxetine treatment invoked rectifying effects in OBX animals only in the high luminance open field by increasing the rate of habituation. Both acute and subchronic administration of lorazepam also reduced OBX hyperactivity but did so only by decreasing the residual rate of responding. As expected, lorazepam administration significantly increased the ratio of open-to-total arm activity in the elevated plus maze. These findings suggest that OBX responding in the open field may be maladaptive, reflecting an inability to modify behavior appropriately in certain environmental contexts. Chronic antidepressant treatment enhances habituation of OBX animals only under more stressful or aversive conditions and appears to do so in a manner temporally distinct from anxiolytic treatment.

Evaluation of the Skin and Cancer Foundation standard series in the diagnosis of allergic contact dermatitis

The use of a standard series of 37 allergens was evaluated in a retrospective study of 817 consecutive patients seen between April 1988 and January 1993 at the Skin and Cancer Foundation, Melbourne, Australia. Of the 316 patients with clinically relevant patch test results, 134 (42%) reacted to an allergen in the standard series alone, while an additional 122 (39%) had reactions to allergens in both the standard and supplementary series. The remaining 60 (19%) patients reacted only to allergens in the supplementary series. These data suggest that the use of our standard series alone will detect about 80% of allergic contact dermatitis cases, but that many of these may be insufficiently evaluated. Use of supplementary allergen testing in a specialised clinic is recommended for patients who may have allergic contact dermatitis.

Nb(9)PdAs(7): a unique arrangement in the M(n2+3n+2)X(n2+n)Y family of hexagonal structures

The ternary transition-metal arsenide Nb(9)PdAs(7) has been prepared through reaction of the elements, and its structure has been determined by single-crystal X-ray diffraction methods. It adopts a new structure type (Pearson symbol hP51, hexagonal, space group P6, Z = 3), with unit cell parameters a = 16.6955(6) and c = 3.5582(1) A. The structure contains assemblies of As-centered trigonal prisms that extend as triangular columns through sharing of the triangular faces. Not only does Nb(9)PdAs(7) extend a family of hexagonal structures with general formula M(n2+3n+2)X(n2+n)Y to n = 4, the highest member known thus far, but it also displays the unique feature in which there are two distinct types of triangular columns, one having corner atoms (Pd) different from the other atoms (Nb). Structural relationships between members of the M(n2+3n+2)X(n2+n)Y family are presented. The chemical bonding in Nb(9)PdAs(7) was analyzed through an extended Hückel band structure calculation.

Nb4Pd0.5ZSb2 (Z = Cr, Fe, Co, Ni, Si): the first ordered quaternary variants of the W5Si3-type structure

A family of quaternary (or pseudoquaternary) antimonides Nb4Pd0.5ZSb2 (Z = Cr, Fe, Co, Ni, Si) containing up to three transition metals in an ordered arrangement has been prepared by reactions of the elements. These antimonides are isostructural, crystallizing as substitutional variants of the W5Si3-type structure (tetragonal, space group -I4/mcm, Z = 4) with unit cell parameters a = 10.4407(3) A and c = 5.0020(2) A for Nb4Pd0.5Cr0.28(3)Si0.72Sb2, a = 10.4825(6) A and c = 4.9543(3) A for Nb4Pd0.5FeSb2, a = 10.4603(5) A and c = 4.9457(3) A for Nb4Pd0.5CoSb2, a = 10.4332(7) A and c = 4.9649(3) A for Nb4Pd0.5Ni0.78(1)Sb2, and a = 10.3895(10) A and c = 4.9634(4) A for Nb4Pd0.5SiSb2. They are distinguished by the filling of interstitial Z atoms into the centers of Nb8 square antiprismatic clusters that are linked by PdSb4 tetrahedra. The Nb8 square antiprisms share opposite square faces to form one-dimensional chains along the c axis so that Z-Z bonding distances of approximately 2.5 A result. Extended Hückel band structure calculations were carried out to interpret the homo- and heteroatomic metal-metal interactions in the structure. The resistivity of one member, Nb4Pd0.5SiSb2, was measured, indicating metallic behavior.

Biflavonoids as novel antituberculosis agents

A series of naturally occurring and synthetic biflavonoids was evaluated for inhibitory activity against Mycobacterium tuberculosis H37Rv (Mtb). Compounds 6, 24, and 25 demonstrated 96, 95, and 87% inhibition, respectively, at a screening concentration of 12.5 microg/mL. The type of linkage and the presence of methoxy- and nitro-substituents in biflavonoids may contribute to the observed inhibitory activity. The results of this study represent the discovery of biflavonoids as a potential new class of antituberculosis agent.

Layered rare-earth gallium antimonides REGaSb(2) (RE = La--Nd, Sm)

The ternary rare-earth gallium antimonides, REGaSb(2) (RE = La--Nd, Sm), have been synthesized through reaction of the elements. The structures of SmGaSb(2) (orthorhombic, space group D(5)(2)-C222(1), Z = 4, a = 4.3087(5) A, b = 22.093(4) A, c = 4.3319(4) A) and NdGaSb(2) (tetragonal, space group D(19)(4h)-I4(1)/amd, Z = 8, a = 4.3486(3) A, c = 44.579(8) A) have been determined by single-crystal X-ray diffraction. The SmGaSb(2)-type structure is adopted for RE = La and Sm, whereas the NdGaSb(2)-type structure is adopted for RE = Ce--Nd. The layered SmGaSb(2) and NdGaSb(2) structures are stacking variants of each other. In both structures, two-dimensional layers of composition (2)(infinity)[GaSb] are separated from square nets of Sb atoms [Sb] by RE atoms. Alternatively, the structures may be considered as resulting from the insertion of zigzag Ga chains between (2)(infinity)[RE Sb(2)] slabs. In SmGaSb(2), all of the Ga chains are parallel and the (2)(infinity)[SmSb(2)] layers are stacked in a ZrSi(2)-type arrangement. In NdGaSb(2), the Ga chains alternate in direction, resulting in a doubling of the long axis relative to SmGaSb(2), and the (2)(infinity)[NdSb(2)] layers are stacked in a Zr(3)Al(4)Si(5)-type arrangement. Extended Hückel band structure calculations are used to explain the bonding in the [GaSb(2)](3-) substructure.

Ternary early-transition-metal palladium pnictides Zr3Pd4P3, Hf3Pd4P3, HfPdSb, and Nb5Pd4P4

Several ternary palladium pnictides of the early transition metals have been prepared by arc-melting of the elemental metals and the binary pnictides ZrP, HfP, HfSb2, or NbP, and their structures have been determined by X-ray diffraction methods. The phosphides M3Pd4P3 (M = Zr, Hf) adopt a new structure type (Pearson symbol oP40), crystallizing in the orthorhombic space group Pnma with Z = 4 and unit cell parameters of a = 16.387(2), b = 3.8258(5), and c = 9.979(1) A for Zr3Pd4P3 and a = 16.340(2), b = 3.7867(3), and c = 9.954(1) A for Hf3Pd4P3. The antimonide HfPdSb was identified by powder X-ray diffraction (orthorhombic, Pnma, Z = 4, a = 6.754(1) A, b = 4.204(1) A, and c = 7.701(2) A) and confirmed to be isostructural to ZrPdSb, which adopts the TiNiSi-type structure. The phosphide Nb5Pd4P4 adopts the Nb5Cu4Si4-type structure, crystallizing in the tetragonal space group I4/m with Z = 2, a = 10.306(1) A, and c = 3.6372(5) A. Coordination geometries of pentacapped pentagonal prisms for the early transition metal, tetracapped distorted tetragonal prisms for Pd, and tricapped trigonal prisms for the pnicogen are found in the three structures; tetracapped tetragonal prisms for Nb are also found in Nb5-Pd4P4. In common with many metal-rich compounds whose metal-to-nonmetal ratio is equal or close to 2:1, the variety of structures formed by these ternary palladium pnictides arises from the differing connectivity of pnicogen-filled trigonal prisms. Pnicogen-pnicogen bonds are absent in these structures, but metal-metal bonds (in addition to metal-pnicogen bonds) are important interactions, as verified by extended Hückel band structure calculations on Zr3Pd4P3.

Antidepressants preferentially enhance habituation to novelty in the olfactory bulbectomized rat

RATIONALE

The mechanisms whereby antidepressant drugs exert their therapeutic effects remain unknown. Responses to stressful stimuli are currently thought to contribute to the onset and course of affective disorders. It has been postulated that antidepressants might act by ameliorating response patterns to challenging life events, such as processes of reactivity and/or habituation.

OBJECTIVE

Using the olfactory bulbectomy (OBX) rat model, this study examined the effects of various antidepressants on measures of reactivity and habituation in behavioral tests assessing responses to novel stimuli.

METHODS

Sham-operated and OBX rats received 21 daily injections of fluoxetine (10 mg/kg), amitriptyline (10 mg/kg), desipramine (10 mg/kg), buspirone (3 mg/kg), or vehicle. Forty-eight hours after the last injection, animals were tested in the open field, elevated plus maze, and startle apparatus. For each test, time series data were collected and fit with exponential random effects models, in which estimated parameters assessed behavioral reactivity and habituation.

RESULTS

Relative to sham controls, OBX rats displayed increased total locomotor activity in the open field and exhibited increased open arm behavior in the elevated plus maze. Through comparison with zinc sulfate-treated anosmic controls, these OBX-induced increases were attributed to both an augmentation of initial reactivity due to anosmia and an attenuation of the average rate of habituation. Chronic antidepressant treatment did not reduce the anosmia-related initial reactivity levels of OBX rats to that of sham controls. Rather, the antidepressants evoked their restorative effects by increasing the rate of habituation.

CONCLUSIONS

These findings suggest that antidepressants restore normal responding by permitting more effective adaptation to novel stimuli.

Unilateral pigmented purpuric eruption

Three cases of unilateral pigmented purpuric eruption (UPPE) occurring in children aged between 7 and 12 years are reported. The lesions were asymptomatic and occurred on the lower limb and torso; one case demonstrated a quadrantic configuration with a sharp midline cutoff. The purpuric component resolved spontaneously within 3 months in all cases, while pigmentation showed partial resolution in the two cases followed up for 12 months. Our cases support previous reports of UPPE being a benign self-limiting condition mainly affecting young patients. The cause is unknown.

The descriptive epidemiology of atopic dermatitis in the community

Atopic dermatitis (AD) is a common condition in the community, particularly amongst children. Although comparison of prevalence data between surveys is made difficult by differences in methodology, the available data suggest that there has been a substantial rise in the prevalence of AD, and that social, geographical and racial variation in disease frequency exists. There is a lack of quality data relating to the prognosis of AD. Recently a reliable set of diagnostic criteria has been developed and a number of severity scoring systems have been proposed for use in epidemiological studies.

The cumulative incidence of atopic dermatitis in the first 12 months among Chinese, Vietnamese, and Caucasian infants born in Melbourne, Australia

BACKGROUND

Atopic dermatitis (AD), a disease with both inherited and environmental components determining its clinical expression, has been reported to be more frequent in people of Asian origin.

OBJECTIVE

Our purpose was to compare the 12-month cumulative incidence of AD in Caucasian, Chinese, and Vietnamese babies born in Australia.

METHODS

Sixty-two Caucasian, 61 Chinese, and 59 Vietnamese babies born in Melbourne, Australia were examined soon after birth and then followed up for 12 months to assess the frequency of AD. Parental education, employment history, and housing conditions were also recorded.

RESULTS

AD developed in 21% of Caucasians, 44% of Chinese, and 17% of Vietnamese infants. Parents of the Chinese and Caucasian infants had similar socioeconomic and housing conditions compared with the parents of the Vietnamese infants, who tended to be of lower socioeconomic status with communal housing and lack of plush-pile carpeting.

CONCLUSION

The high incidence of AD in Chinese compared with Caucasian infants tends to reflect genetic differences between the two populations, whereas the difference in incidence between the Chinese and Vietnamese infants possibly reflects more the environmental contribution to disease expression.

Modulation of conduction block in leech mechanosensory neurons

Conduction block is a mechanism of activity-dependent neuronal plasticity, but little is known about its possible neuromodulation. Extensive activity in leech touch (T), pressure (P), and nociceptive (N) mechanosensory neurons results in conduction block of their minor receptive fields. We have examined whether the duration of conduction block could be modulated by the serotonergic Retzius neurons or by application of serotonin (5-HT). Activation of one Retzius cell reduced the duration of conduction block in T and P cell posterior fields, but their anterior fields and N cell fields were unaffected. Perfusion with 5-HT had stronger effects, reducing the duration of conduction block in T, P, and lateral N cells in the posterior fields and either reducing or more often enhancing the expression of conduction block in anterior fields. The effects of 5-HT on posterior fields were blocked by the nonspecific 5-HT antagonist methysergide and were partly suppressed by the 5-HT2 antagonist ketanserin. To determine the site of 5-HT action, the central ganglion or peripheral skin was perfused independently. T and to a greater extent P cells showed a preferential sensitivity to application of 5-HT onto the central ganglion. Interestingly, medial N cells exhibited a progressive decrease in the duration of conduction block during repeated trials ("wind-up") that was unaffected by 5-HT. We conclude that secretion of 5-HT by the Retzius cells has a central modulatory effect on the duration of conduction block in T, P, and lateral N cells.

Recurrent nonmelanoma skin cancer in southern Australia

BACKGROUND AND OBJECTIVE

In retrospective studies of non-melanoma skin cancers, the recurrence rates were relatively high. This study had as its aim to determine the recurrence rate of nonmelanoma skin cancer (NMSC) and prospectively, risk factors for recurrence in southern Australia.

STUDY DESIGN

This is a prospective study of outpatients with histologically confirmed NMSC. All patients seen by a dermatologist between November 1988 and November 1989 were entered into the study and followed for at least 3 years. Any recurrent NMSCS were removed and recorded.

RESULTS

Four hundred and eighty-one patients were entered and 420 followed for at least 3 years. A recurrent NMSC developed in 8% (adjusted for losses). A multivariate analysis determined that the main risk factor for recurrence within the first 3 years of follow-up was the number of NMSC a patient had when entering into the study. Those with 3 to nine NMSC were five times more likely to develop a recurrence than those with less than three NMSC. Those with 10 or more NMSC were 25 times more likely to develop a recurrence. Age, sex, and types of skin cancers removed were not risk factors within the first 3 years of follow-up.

CONCLUSION

Patients who have had multiple skin cancers require careful follow-up because of the risk of developing recurrences.

Cell-mediated immunity of patients who have had basal cell carcinomas

The cell-mediated immunity of patients who had basal cell carcinomas (BCCs) removed was studied by measuring cuntaneous delayed hypersensitivity reactions to recall antigens (Multitest CMI, Pasteur-Merieux), and by measuring lymphocyte counts and subsets. One group of patients had multiple BCCs (3 or more) removed and were considered to have a high risk of new BCC formation. The other group consisted of patients who had one BCC and had not developed another within 5 years; these were considered to have a low risk of new BCC formation. The low-risk patients had significantly larger cutaneous reactions to recall antigens (p < 0.05) and significantly fewer were anergic (p < 0.01). There was a correlation between smaller cutaneous reactions and increasing numbers of BCCs (p < 0.05). There was no significant difference between the groups in lymphocyte counts or subsets, but the low-risk patients had a significantly higher CD4:CD8 ratio (p < 0.05) than the high-risk group. The Multitest CMI test can be used to determine which patients are at risk of developing many BCCs.

The development of non-melanocytic skin cancers in people with a history of skin cancer

OBJECTIVE

To determine the incidence of new skin cancer formation in people who have had skin cancer removed.

STUDY DESIGN

A prospective study of Melbourne out-patients with histologically confirmed non-melanoma skin cancer (NMSC). All patients with NMSC seen by one author (D.C.) between November 1988 and November 1989 were entered into the study and reviewed regularly. New skin cancers were removed and recorded.

RESULTS

Four hundred and eighty-one patients were entered and 420 followed for at least 3 years. New NMSC developed in 60% (adjusted for losses) by the end of 3 years. A multivariate analysis determined that the main risk factor for new NMSC formation was the number of previous skin cancers that a patient had. Those who had had multiple skin cancers (3 or more) were at significantly greater risk than those with less than 3. Age, sex and type of NMSC were not risk factors for new skin cancer formation.

CONCLUSION

Patients with NMSC require long-term follow-up because of the risk of new skin cancer formation. Those with multiple NMSC need more careful follow-up, and possibly more frequent examinations, because they are at greater risk.

Metastases from squamous cell carcinoma of the skin in southern Australia

BACKGROUND

The frequency with which squamous cell carcinoma (SCC) of the skin metastasizes is a matter of dispute. Studies from private practices have reported much lower rates than hospital-based surveys, and one school of thought is that SCCs which arise in sun-damaged skin have a low risk of metastasis.

METHODS

A prospective study of out-patients with histologically confirmed SCC was undertaken in southern Australia, a region with a very high incidence of skin cancer.

RESULTS

Between November 1988 and November 1989, 481 patients were entered into the study and 420 followed for at least 3 years. An SCC was the initial diagnosis for 73 patients, 3 were immunosuppressed and 2 had an SCC of the lip, leaving 68 immunocompetent patients with SCC of the skin. Metastatic SCC developed in 2 patients (5.8% adjusted for losses) within 3 years. The SCCs were small and arose in sun-damaged skin.

CONCLUSION

Patients with SCC of the skin need a careful follow-up because of the risk of metastasis.

Synthesis of the coenzymes adenosine diphosphate glucose, guanosine diphosphate glucose, and cytidine diphosphoethanolamine under primitive Earth conditions

The nonenzymatic synthesis of the coenzymes adenosine diphosphate glucose (ADPG), guanosine diphosphate glucose (GDPG), and cytidine diphosphoethanolamine (CDP-ethanolamine) has been carried out under conditions considered to have been prevalent on the early Earth. The production of these compounds was performed by allowing simple precursor molecules to react under aqueous solutions, at moderate temperatures and short periods of time, with mediation by cyanamide or urea. These two condensing agents are considered to have been present in significant amounts on the primitive Earth and have been previously used in the nonenzymatic synthesis of several other important biochemical compounds. In our experiments, ADPG was obtained by heating glucose-1-phosphate (G1P) and ATP in the presence of cyanamide for 24 h at 70 degrees C. The reaction of G1P and GTP under the same conditions yielded GDPG. The cyanamide-mediated production of CDP-ethanolamine was carried out by reacting a mixture of ethanolamine phosphate and CTP for 24 h at 70 degrees C. The separation and identification of the reaction products was carried out by paper chromatography, thin-layer chromatography, high performance thin-layer chromatography, high performance liquid chromatography, both normal and reverse-phase, UV spectroscopy, enzymatic assays, and acid hydrolysis. Due to the mild conditions employed, and to the relative ease of these reactions, these studies offer a simple attractive system for the nonenzymatic synthesis of phosphorylated high-energy metabolic intermediates under conditions considered to have been prevalent on the ancient Earth.

Non-enzymatic synthesis of the coenzymes, uridine diphosphate glucose and cytidine diphosphate choline, and other phosphorylated metabolic intermediates

The synthesis of uridine diphosphate glucose (UDPG), cytidine diphosphate choline (CDP-choline), glucose-1-phosphate (G1P) and glucose-6-phosphate (G6P) has been accomplished under simulated prebiotic conditions using urea and cyanamide, two condensing agents considered to have been present on the primitive Earth. The synthesis of UDPG was carried out by reacting G1P and UTP at 70 degrees C for 24 hours in the presence of the condensing agents in an aqueous medium. CDP-choline was obtained under the same conditions by reacting choline phosphate and CTP X G1P and G6P were synthesized from glucose and inorganic phosphate at 70 degrees C for 16 hours. Separation and identification of the reaction products have been performed by paper chromatography, thin layer chromatography, enzymatic analysis and ion pair reverse phase high performance liquid chromatography. These results suggest that metabolic intermediates could have been synthesized on the primitive Earth from simple precursors by means of prebiotic condensing agents.