A systematic review of prenatally diagnosed vein of Galen malformations: prenatal predictive markers and management from fetal life to childhood.

Introduction: Vein of Galen malformations (VGMs) account for less than 1% of all intracranial vascular malformations. However, in fetal and pediatric populations, they represent the most common vascular malformation of the brain. For the effective management of this condition, an optimal knowledge of its prenatal and postnatal clinical features is mandatory. Methods: Articles published between 1 January 2003 and 31 January 2024, reported in PubMed and EMBASE, were evaluated for a systematic review analyzing the prenatal and postnatal features and management of fetal VGMs. Results: Thirty-one papers reporting information on 51 prenatally diagnosed VGMs were included. The most common prenatal features were fetal hydrocephalus (39%) and cardiomegaly (56%). Postnatal data for 43 VGM cases are described. The overall mortality was 58.14%. In total, 77.78% of the survivors had normal development. Conclusions: Close follow-up and a multidisciplinary approach are mandatory to manage this condition. Our study aimed to provide a guide for gynecologists, neonatologists, cardiologists, and neuroradiologists.

Utero-cervical angle to predict the risk of spontaneous preterm birth: a review of literature.

BACKGROUND: The aim of this paper was to evaluate the predictive role of the uterocervical angle (UCA) in spontaneous preterm birth (sPTB). METHODS: A systematic review of the literature was performed including all studies reporting the association between UCA and sPTB. Searches were performed with the use of a combination of keywords: "cervical length," "uterocervical angle," and "preterm birth" from inception of each database to March 2022. The statistical evaluations were carried out using the Comprehensive Meta-Analysis version 3 (Biostat Inc. USA). RESULTS: Sixteen studies all conducted on the second trimester UCA as well as its association with sPTB were included in this study. In all studies the measurements of cervical length (CL) and UCA were performer in the second trimester, except in one that in the third trimester. In most studies the CL is greater than 30 mm and the UCA is greater than 110 °. In seven studies women with symptoms were considered while in 8 studies the women were asymptomatic. CONCLUSIONS: It is too early for it to reach a firm conclusion on UCA utilization in clinical settings. A higher UCA measurement (greater than 150°) is an important risk factor for deliveries before 37 weeks' gestation. It provides a higher diagnostic performance in high risk patients than the CL measurement. However, the most relevant ultrasound parameter for the prediction of delivery within the next few data in women with preterm delivery remains the cervical length. There is a need to consider both markers and create protocols so that the values obtained with UCA and those with CL can make a real contribution to decisions to be made rather than using only CL.

The unpredictable clinical course of an abdominal cyst diagnosed in the prenatal period: A case report.

Enteric duplication cysts are rare congenital malformations of the gastrointestinal tract. Prenatal diagnosis can be achieved through ultrasound, which may reveal a cystic mass, though the differential diagnosis is broad. We report a case in which the prenatal ultrasound detection of an abdominal cystic mass prompted postnatal magnetic resonance imaging, leading to the diagnosis of an enteric duplication cyst. At 6 weeks of age, the infant developed an obstruction of the small bowel, requiring urgent surgical intervention. This case underscores the difficulties in differentiating abdominal cysts prenatally. Thorough prenatal and neonatal follow-up is crucial, and postnatal magnetic resonance imaging is sometimes essential for accurate diagnosis. The clinical course can be unpredictable, and complications that may arise could necessitate urgent surgical treatment.

Prenatal Diagnosis of an Intrathoracic Left Kidney Associated with Congenital Diaphragmatic Hernia: Case Report and Systematic Review.

INTRODUCTION: A congenital intrathoracic kidney (ITK) is a rare anomaly that is recognized to have four causes: renal ectopia with an intact diaphragm, diaphragmatic eventration, diaphragmatic hernia, and traumatic diaphragmatic rupture. We report a case of a prenatal-diagnosed ITK related to a congenital diaphragmatic hernia (CDH) and conducted a systematic review of all cases of the prenatal diagnosis of this association. CASE PRESENTATION: A fetal ultrasound scan at 22 gestational weeks showed left CDH and ITK, hyperechoic left lung parenchyma, and mediastinal shift. The fetal echocardiography and karyotype were normal. Magnetic resonance imaging at 30 gestational weeks confirmed the ultrasound suspicion of left CDH in association with bowel and left kidney herniation. The fetal growth, amniotic fluid, and Doppler indices remained within the normal range over time. The woman delivered the newborn via an at-term spontaneous vaginal delivery. The newborn was stabilized and underwent non-urgent surgical correction; the postoperative course was uneventful. CONCLUSIONS: CDH is the rarest cause of ITK; we found only eleven cases describing this association. The mean gestational age at diagnosis was 29 ± 4 weeks and 4 days. There were seven cases of right and four cases of left CDH. There were associated anomalies in only three fetuses. All women delivered live babies, the herniated kidneys showed no functional damage after their surgical correction, and the prognosis was favorable after surgical repair. The prenatal diagnosis and counseling of this condition are important in planning adequate prenatal and postnatal management in order to improve neonatal outcomes.

Fetal Cerebellar Area: Ultrasound Reference Ranges at 13-39 Weeks of Gestation.

BACKGROUND AND OBJECTIVES: The present study aims to provide prenatal 2-dimensional ultrasonographic (2D-US) nomograms of the normal cerebellar area. MATERIALS AND METHODS: This is a prospective cross-sectional analysis of 252 normal singleton pregnancies, ranging from 13 to 39 weeks of gestation. The operator performed measurements of the fetal cerebellar area in the transverse plane using 2D-US. The relationship between cerebellar area and gestational age (GA) was determined through regression equations. RESULTS: A significant, strong positive correlation was investigated between the cerebellar area with GA (r-value = 0.89), and a positive correlation indicates that with increasing GA, the cerebellar area increased in all the participants of the study. Several 2D-US nomograms of the normal cerebellar area were provided, and an increase of 0.4% in the cerebellar area each week of GA was reported. CONCLUSIONS: We presented information on the typical dimensions of the fetal cerebellar area throughout gestation. In future studies, it could be evaluated how the cerebellar area changes with cerebellar abnormalities. It should be established if calculating the cerebellar area in addition to the routine transverse cerebellar diameter may help in discriminating posterior fossa anomalies or even help to identify anomalies that would otherwise remain undetected.

Enhanced toxicity of silver nanoparticles in transgenic Caenorhabditis elegans expressing amyloidogenic proteins.

The increasing number of applications of silver nanoparticles (AgNP) prompted us to assess their toxicity in vivo. We have investigated their effects on wild type and transgenic Caenorhabditis elegans (C. elegans) strains expressing two prototypic amyloidogenic proteins: ß2-microglobulin and Aß peptide3-42. The use of C. elegans allowed us to highlight AgNP toxicity in the early phase of the worm's life cycle (LC50 survival, 0.9 µg/ml). A comparative analysis of LC50 values revealed that our nematode strains were more sensitive to assess AgNP toxicity than the cell lines, classically used in toxicity tests. Movement and superoxide production in the adult population were significantly affected by exposure to AgNP; the transgenic strains were more affected than the wild type worms. Our screening approach could be applied to other types of nanomaterials that can enter the body and express any nanostructure-related bioactivities. We propose that C. elegans reproducing the molecular events associated with protein misfolding diseases, e.g. Alzheimer's disease and systemic amyloidosis, may help to investigate the specific toxicity of a range of potentially harmful molecules. Our study suggests that transgenic C. elegans may be used to predict the effect of chemicals in a "fragile population", where an underlying pathologic state may amplify their toxicity.

SJS/TEN overlap associated with lomefloxacin: case report and molecular typing studies.

BACKGROUND: Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN) may develop in susceptible patients after administration of different drugs. Only mild cutaneous reactions have been related to lomefloxacin. A correlation between human leucocyte antigen (HLA) and cutaneous adverse reaction has been identified. CASE REPORT: Twenty-four hours after intake of lomefloxacin, a 30-year-old Caucasian woman developed a severe skin reaction with symptoms suggesting SJS/TEN. The fast onset reaction worsened with skin blisters and 20% body surface area skin detachment within 48 h. Burn unit admittance was required; corticosteroids and human immunoglobulins were administered. Complete recovery occurred within 3 months, except for epidermal discoloration. Molecular studies showed a peculiar profile characterized by HLA class I genotype rich of ligands for natural killer cell immunoglobulin-like receptors (KIR) and HLA class II haplotype, HLA-DRB1*03:01,DQB1*02:01, prone to autoimmunity. CONCLUSION: While the HLA profile approaches our case to other well-documented drug-induced SJS/TEN, KIR involvement still remains puzzling.

Assessment of cellular responses after short- and long-term exposure to silver nanoparticles in human neuroblastoma (SH-SY5Y) and astrocytoma (D384) cells.

Silver nanoparticle (AgNP, 20 nm) neurotoxicity was evaluated by an integrated in vitro testing protocol employing human cerebral (SH-SY5Y and D384) cell lines. Cellular response after short-term (4-48 h, 1-100 µ g/ml) and prolonged exposure (up to 10 days, 0.5-50 µ g/ml) to AgNP was assessed by MTT, calcein-AM/PI, clonogenic tests. Pulmonary A549 cells were employed for data comparison along with silver nitrate as metal ionic form. Short-term data: (i) AgNP produced dose- and time-dependent mitochondrial metabolism changes and cell membrane damage (effects starting at 25 µ g/ml after 4 h: EC50s were 40.7 ± 2.0 and 49.5 ± 2.1 µ g/ml for SH-SY5Y and D384, respectively). A549 were less vulnerable; (ii) AgNP doses of ≤ 18 µ g/ml were noncytotoxic; (iii) AgNO3 induced more pronounced effects compared to AgNP on cerebral cells. Long-term data: (i) low AgNP doses (≤ 1 µ g/ml) compromised proliferative capacity of all cell types (cell sensibility: SHSY5Y > A549 > D384). Colony number decrease in SH-SY5Y and D384 was 50% and 25%, respectively, at 1 µ g/ml, and lower dose (0.5 µ g/ml) was significantly effective towards SH-SY5Y and pulmonary cells; (ii) cell proliferation activity was more affected by AgNO3 than AgNPs. In summary, AgNP-induced cytotoxic effects after short-term and prolonged exposure (even at low doses) were evidenced regardless of cell model types.

In vitro toxicity evaluation of engineered cadmium-coated silica nanoparticles on human pulmonary cells.

Cytotoxicity of cadmium-containing silica nanoparticles Cd-SiO2NPs (0.05-100 µg/mL) versus SiO2NPs and CdCl2 was evaluated by an in vitro test battery in A549 by assessing (i) mitochondrial function, (ii) membrane integrity/cell morphology, (iii) cell growth/proliferation, (iv) apoptotic pathway, (v) oxidative stress, after short- (24-48 h) and long-term (10 days) exposure. Both Cd-SiO2NPs and CdCl2 produced dose-dependent cytotoxic effects: (i) MTT-assay: similar cytotoxicity pattern was observed at both 24 and 48 h, with a more Cd-SiO2NPs pronounced effect than CdCl2. Cd-SiO2NPs induced mortality (about 50%) at 1 µ g/mL, CdCl2 at 25 µ g/mL; (ii) calcein-AM/PI staining: decrease in cell viability, noticeable at 25 µ g/mL, enhanced markedly at 50 and 100 µ g/mL, after 24 h. Cd-SiO2NPs induced higher mortality than CdCl2 (25% versus 4%, resp., at 25 µ g/mL) with further exacerbation after 48h; (iii) clonogenic assay: exposure for longer period (10 days) compromised the A549 proliferative capacity at very low dose (0.05 µ g/mL); (iv) a progressive activation of caspase-3 immunolabelling was detected already at 1 µ g/mL; (v) GSH intracellular level was modified by all compounds. In summary, in vitro data demonstrated that both Cd-SiO2NPs and CdCl2 affected all investigated endpoints, more markedly after Cd-SiO2NPs, while SiO2NPs influenced GSH only.

Safety evaluation of engineered nanomaterials for health risk assessment: an experimental tiered testing approach using pristine and functionalized carbon nanotubes.

Increasing application of engineered nanomaterials within occupational, environmental, and consumer settings has raised the levels of public concern regarding possible adverse effects on human health. We applied a tiered testing strategy including (i) a first in vitro stage to investigate general toxicity endpoints, followed by (ii) a focused in vivo experiment. Cytotoxicity of laboratory-made functionalized multiwalled carbon nanotubes (CNTs) (i.e., MW-COOH and MW-NH2), compared to pristine MWCNTs, carbon black, and silica, has been assessed in human A549 pneumocytes by MTT assay and calcein/propidium iodide (PI) staining. Purity and physicochemical properties of the test nanomaterials were also determined. Subsequently, pulmonary toxic effects were assessed in rats, 16 days after MWCNTs i.t. administration (1 mg/kg b.w.), investigating lung histopathology and monitoring several markers of lung toxicity, inflammation, and fibrosis. In vitro data: calcein/PI test indicated no cell viability loss after all CNTs treatment; MTT assay showed false positive cytotoxic response, occurring not dose dependently at exceedingly low CNT concentrations (1 µ g/mL). In vivo results demonstrated a general pulmonary toxicity coupled with inflammatory response, without overt signs of fibrosis and granuloma formation, irrespective of nanotube functionalization. This multitiered approach contributed to clarifying the CNT toxicity mechanisms improving the overall understanding of the possible adverse outcomes resulting from CNT exposure.

Apoptosis induction and histological changes in rat kidney following Cd-doped silica nanoparticle exposure: evidence of persisting effects.

Abstract Histological and immunocytochemical methods were used to examine rat's renal responses to intratracheal (i.t.) instillation of model cadmium-containing silica nanoparticles (Cd-SiNPs) and also exploring whether these potential modifications would be associated with toxicogenomic changes. Renal effects of Cd-SiNPs (1 mg/rat), CdCl2 (400 µg/rat), SiNPs (600 µg/rat) or 0.1 ml saline (control), assessed 7 and 30 d post-i.t., included (i) induction of apoptosis, (ii) cell proliferation and (iii) the overall toxic response evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, proliferating cell nuclear antigen (PCNA) immunohistochemistry as well as Periodic acid Schiff and Hematoxylin & Eosin, respectively. Area-specific apoptosis was observed in all treatment groups, the cortex and inner medulla being the most affected regions: the apoptotic changes were apparent seven days post-exposure in both areas and were still observable in inner medulla at day 30. Apoptotic frequency increase was more pronounced in Cd-SiNP-treated animals compared to either CdCl2 or SiNPs groups. At day 7, the observed parallel increased number of PCNA immunopositive cells may be associated with an enhanced cell proliferation aimed at replacing the damaged cells. Histopathological findings demonstrated comparable morphological changes of the renal structure (at glomerular and tubular levels) occurring after all treatments at both time-points and more markedly 30 d after instillation. Both morphological and toxicogenomic evaluations confirmed long-lasting renal effects of Cd-SiNPs on apoptosis and regulatory processes. Bare SiNPs i.t. administration caused morphological and apoptotic changes but did not modify gene expression profile in kidney. These findings substantiate the notion that multiple assays and an integrated testing strategy should be recommended to characterize toxicological responses to nanoparticles in mammalian systems.

Pulmonary toxicity of instilled cadmium-doped silica nanoparticles during acute and subacute stages in rats.

Potential risk associated with new nanomaterial exposure needs to be assessed. This in vivo study investigated pulmonary effects of engineered cadmium-containing silica nanoparticles Cd/SiNPs (1 mg/rat), silica SiNPs (600 µg/rat) and CdCl2 (400 µg/rat) 1, 7 and 30 days after intratracheal instillation. Comprehensive histopathological and immunocytochemical characterization of lung damage in terms of apoptosis, cell proliferation, inflammation, fibrosis and metabolism were obtained. After exposure to all treatments, lung parenchyma showed injury patterns characterized by collapsed alveoli, inflammation, granuloma formation, thickened alveolar septa and bronchiolar epithelium exfoliation. Type II pneumocytes, containing scarcely surfactant-lamellated bodies, were also observed. Apoptotic phenomena enhanced as following, Cd/SiNPs>CdCl2> SiNPs. In parallel with these findings, a significant increase of PCNA-immunoreactive cells was detected together with high mitotic activity. Cellular localization and distribution of IL-6, IP-10 and TGF-ß1 revealed an increased expression of these cytokines as evidence of an enhanced cellular inflammatory response. CYP450-immunoreactivity was also enhanced, at bronchiolar (e.g. Clara cells) and alveolar (e.g. macrophages) level after both Cd/SiNPs and CdCl2. These overall effects were observed acutely and lasted until the 30th day, with Cd/SiNPs producing the most marked effects. Collagen-immunolabelling changed particularly 7 and 30 days after Cd/SiNPs, when a strong stromal fibrogenic reaction occurred. The present findings suggest that Cd/SiNPs produce significantly greater pulmonary alterations than either SiNPs or CdCl2 under the present experimental conditions.

Novel tools for blood inflammatory markers detection in monitoring air pollution-induced cardio-respiratory symptoms.

There is strong epidemiological evidence that air pollution exposure (short- and long-term, i.e. < 24 hr to 3 weeks, and year/s) is related to exacerbation of cardiovascular and respiratory diseases. Data from toxicological and basic science/molecular studies, controlled animal and human exposures and human panel studies have demonstrated several mechanisms by which particle exposure may both trigger acute events as well as prompt the chronic development of cardiovascular diseases. These pollutant-mediated biological mechanisms are supporting the potential use of haematic (inflammation/coagulation/oxidative stress) markers of effects in cardio-respiratory diseases. Various examples from in vitro, in vivo and epidemiological investigations are reported, together with some novel technologies that should provide with new tools for research in these diseases and improve the knowledge about any linkage of local and systemic inflammation and clinical features of these diseases (in particular COPD), including lung function, exacerbations, disease progression, and mortality.

Long-lasting oxidative pulmonary insult in rat after intratracheal instillation of silica nanoparticles doped with cadmium.

Silica/cadmium containing nanomaterials are now produced on industrial scale due to their potential for a variety of technological applications. Nevertheless, information on toxicity, exposure and health impact of these nanomaterials is still limited. In this study, in vivo effects of silica nanoparticles (SiNPs) doped with Cd (SiNPs-Cd, 1mg/rat), soluble CdCl(2) (400 µg/rat), or SiNPs (600 µg/rat) have been investigated by evaluating F(2)-isoprostanes (F(2)-IsoPs), superoxide dismutase (SOD1), inducible nitric oxide synthase (iNOS) and cyclooxygenase type 2 (COX-2) enzymes, as markers of oxidative stress, 24h, 7 and 30 days after intra-tracheal (i.t.) instillation to rats. Free and esterified F(2)-IsoPs were evaluated in lung and plasma samples by GC/NICI-MS/MS analysis, and SOD1, iNOS and COX-2 expression in pulmonary tissue by immunocytochemistry. Thirty days after exposure, pulmonary total F(2)-IsoPs were increased by 56% and 43% in CdCl(2) and SiNPs-Cd groups, respectively, compared to controls (32.8 ± 7.8 ng/g). Parallel elevation of free F(2)-IsoPs was observed in plasma samples (by 113% and 95% in CdCl(2) and SiNPs-Cd groups, respectively), compared to controls (28 ± 8 pg/ml). These effects were already detectable at day 7 and lasted until day 30 post-exposure. Pulmonary SOD1-, iNOS-, and COX-2-immunoreactivity was significantly enhanced in a time-dependent manner (7 days <30 days) after both CdCl(2) and SiNPs-Cd treatments. SiNPs did not influence any of the evaluated endpoints. The results indicate the capacity of engineered SiNPs-Cd to cause long-lasting oxidative tissue injury following pulmonary exposure in rat.

An insidious skin rash without itch.

A 74-year-old female with a 5-year medical history of breast infiltrating lobular carcinoma was admitted to our Rehabilitation Unit ward for left hemiparesis secondary to neurosurgical removal of frontal and right parietal metastatic lesions. After the intervention, prophylactic treatment with the antiepileptic diphenylhydantoin 100 mg/tid was started. On 38th day of drug administration an erythema without itch appeared in jugular and parasternal region and absent in the clothing covered areas, suggesting a contact dermatitis. Next day, the erythema extended to the neck with poorly delineated red plaques. During the following 4 days the patient presented oral stomatitis with fetid breath, atypical targetoid and erythematous confluenced macules. The clinical picture rapidly worsened with vesiculate, bullate lesions and frank skin erosions. The patient was sent to a Dermatology Burn Unit where a therapy with corticosteroids, antibiotics, fluids, albumin and immunoglobulins was administrated. Complete clinical resolution was observed after 1 month without long-term sequelae. Toxic epidermal necrolysis (TEN) is a rare (incidence about 0.01%) adverse drug reaction related to idiosyncratic mechanism, burdened by a mortality rate ranging from 3.2 to 90%. In our patient, TEN covered 63% of body surface, a condition associated with a death risk of 58.3% according to the specific severity illness scale SCORTEN. The disease onset may be insidious, and it could appear as a skin rash without itch; the cutaneous manifestations appear quite lately, then the disease quickly progresses. Early recognition of the disease, especially in oncologic patients, is critical for effective management of this condition in terms of mortality reduction.

A young Indian male with abdominal pain.

A young man with abdominal pain who had radiopaque tablets in his gut is described. Investigations showed the diagnosis of lead poisoning from ayurvedic medicines.

Developmental exposure to methylmercury and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153) affects cerebral dopamine D1-like and D2-like receptors of weanling and pubertal rats.

MeHg (0.5 mg/kg/day) and/or PCB153 (5 mg/kg/day) effects, administered orally to rat dams (GD7-PND21), were explored in PND21 and PND36 offspring brain in terms of density (Bmax) and affinity (Kd) of dopamine D1-like (D1-Rs) and D2-like receptors (D2-Rs), by saturation binding studies. D1-Rs decreased density in both cortex and striatum (15-30%) by MeHg and PCB153, either alone or combined, without additivity in PND21 males. Changes disappeared by PND36. In females, only MeHg caused a 15% Bmax decrease in striatum. D2-Rs enhanced density (23-50%) and reduced affinity in cortex to a similar extent by all treatments in both weanling and pubertal males. Affinity was also decreased in females by all types of exposure at both ages, while density was enhanced by PCB153 only in a delayed manner (PND36). No changes were detected in striatum. In MeHg and MeHg + PCB153 pup cortex, Hg concentrations ranged, on PND21, between 0.25 and 0.89 and 0.94-1.40 µg/g tissue, respectively, and were 5- to sixfold lower 2 weeks later. PCB153 levels, in PCB153 ± MeHg treated rats, were about 15 µg/g tissue (PND21) and 4-8 µg/g tissue (PND36). In striatum, the Hg and PCB153 concentrations were similar to those in cortex. Brain kinetics trend also applied to blood PCB153 or Hg levels. Perinatal exposure to MeHg and/or PCB153 affects D1- and D2-Rs in a gender-, time-, and brain area-dependent manner. Combined treatment does not exacerbate the neurochemical effects of the individual compounds.

Fatal course of foodborne botulism in an eight-month old infant.

An 8-month old girl, weighing 9 kg, was brought by her parents at 8.15 am to the Emergency Department (ED) for a progressive worsening of weakness and acute respiratory failure. On admission, the baby presented with poor oral intake, a weak cry and extremely weak muscular body control. Poor gag and suck, unreactive mydriasis, hypotonia, lethargy and absence of peristalsis were noted. Laboratory data showed severe respiratory acidosis. Chest X-ray, electroencephalography, encephalic CT scan and MRI were all normal, as were cerebrospinal fluid analysis and viral tests. Orotracheal intubation and continuous mechanical ventilation were applied. The patient received fluids, corticosteroids, aerosol therapy, large-spectrum antibiotics and enteral-nutrition. Further investigation revealed ingestion of an improperly prepared home-canned homogenized turkey meal. Type A botulinum neurotoxin was identified. Trivalent botulinum antitoxin, prostigmine and oral activated charcoal were administered. Generalized flaccid paralysis, areflexic bilateral mydriasis, gastric stasis and deep coma persisted for the duration of the hospital stay, and the patient died of severe respiratory failure and cardiac arrest 12 days after ED admission. Botulism poisoning should be suspected in any infant presenting with feeding difficulties, constipation, descendent paralysis or acute respiratory failure. Supportive treatment and antidotal therapy should be performed as soon as a clinical diagnosis is made. We describe a case of foodborne botulism in an 8-month old infant caused by ingestion of an improperly prepared home-canned homogenized turkey meal, representing the youngest fatal case reported in medical literature.

Reduced platelet monoamine oxidase type B activity and lymphocyte muscarinic receptor binding in unmedicated children with attention deficit hyperactivity disorder.

Several lines of evidence support the role of monoaminergic and cholinergic dysregulation in attention deficit hyperactivity disorder (ADHD) and the concept that peripheral blood neurotransmission indices may represent valuable surrogate CNS markers. We determined platelet MAO-B activity (p-MAO-B) and lymphocyte muscarinic cholinergic receptor binding (l-MR) in 44 unmedicated ADHD children (aged 9.1 +/- 2.87 years) and in 26 age-matched controls for comparison. Lower levels of p-MAO-B (approximately 35%) and l-MR (approximately 55%) in ADHD were observed compared with controls. Differences were gender-dependent: p-MAO-B was reduced in males only (5.20 +/- 2.99 vs 8.46 +/- 5.1 nmol mg(-1) protein h(-1) in ADHD and controls, respectively) and l-MR in females only (ADHD vs control: 6.63 +/- 1.75 and 15.30 +/- 8.35 fmol 10(-6) cells). The clinical significance was corroborated by the correlation between these markers and severity of specific symptoms: lower p-MAO-B associated with increased inattention scores (Conners' teacher-rating scale); lower l-MR associated with increased score for oppositional-defiant disorder (ODD) (SNAP-IV); and trend towards correlation between increased inattention (SNAP-IV) and lower l-MR.