Dopamine transporter immunoreactivity in rat brain

The dopamine transporter (DAT) is a primary site for the action of cocaine in inducing euphoria. Its action is necessary for the selectivities of dopaminergic neurotoxins that provide the best current experimental models of Parkinson's disease. In the present report, rat ddpamine transporter-like immunoreactivity (iDAT) was assessed by immunohistochemistry using newly developed polyclonal antisera raised against conjugated peptides corresponding to sequences found in the dopainine transporter's carboxy- and amino-termini. Dense iDAT was observed in patterns consistent with neural processes and terminals in the striatum, nucleus accumbens, olfactory tubercle, nigrostriatal bundle, and lateral habenula. Perikarya in the substantia nigra pars compacts, were immunostained with moderate intensity using one of two immunohistochemical methods, while scattered ventral tegmental area perikarya were stained with somewhat less intensity. Immunoreactive neuronal processes with axonal and dendritic morphologies were stained in the substantia nigra and the paranigral and parabrachialis pigmentosus nuclei of the ventral tegmental area, while sparser processes were noted more medially in the ventral tegmental area. Neuronal processes were found in several laminae in the cingulate cortex, with notable fiber densities in the superficial aspects of lamina I and laminae II/III. The intensities of immunoreactivities in striatum and cerebral cortex were dramatically attenuated ipsilateral to nigrostriatal bundle 6-hydroxydopamine lesions. Specificity of immunostaining was supported by agreement of the results using sera directed against two distinct DAT segments, studies with preimmune and preadsorbed sera and studies of the extracted protein. These antisera identify and reveal details of the distribution of DAT immunoreactivity in rat brain and display ivariations in levels of DAT expression of likely functional significance. © 1995 Wiley-Liss, Inc.     

The Prophylactic Effects of U75412E Pretreatment in a Smoke-Induced Lung Injury Rabbit Model

Abstract: The effects of the lazaroid analogue U75412E (21-[4-(3-ethylamino-2-pyridinyl)-1-piperazinyl]-16α-methylpregna-1,4,9]-(11)-triene-3,20-dione) were examined in an acute lung injury rabbit model. Standard doses of 0, 8 and 16 mM U75412E were aerosolized and ventilated into the lungs for 3 min. via an endotracheal tube. A 60 tidal volume dose of diesel fuel-polycarbonate plastic smoke was then instilled, followed by mechanical ventilation for one hour. Pretreatment with 16 mM U75412E significantly increased blood PaO₂ and pH values, and decreased blood PaCO₂ as compared to smoke only exposures. It also significantly decreased the total cell counts and granulocytes in bronchoalveolar lavage fluid, and the ability of pulmonary alveolar macrophages to produce tumour necrosis factor-α in vitro after cell isolation and culture. Histopathology indicated that 16 mM U75412E pretreatment attenuated increases in wet lung/body weight ratios, inflammatory focus, and interstitial oedema associated with smoke insult. In summary, U75412E pretreatment may possess the potential to improve acute smoke-induced lung injury, in part, through modulation of tumour necrosis factor-α production from pulmonary alveolar macrophages.     

Visual event-related potentials index focused attention within bilateral stimulus arrays. II. Functional dissociation of P1 and N1 components.

Event-related potentials (ERPs) were recorded from 12 subjects as they attended to the left or right hemifield of a visual display while fixating a central point. Stimuli were presented to the left or right visual fields on separate trials (unilateral stimuli) or to both fields simultaneously (bilateral stimuli). In different conditions, the stimulus sequences contained only bilateral stimuli, only unilateral stimuli, or a mixture of unilateral and bilateral stimuli. Bilateral stimuli elicited an enhanced positivity lasting from about 75 to 250 msec that was largest at posterior electrode sites contralateral to the attended hemifield. The early phase of this attention-related positivity appeared to be an enhancement of the exogenous P1 component. In contrast, both the posterior P1 and N1 components were enhanced in response to attended unilateral stimuli. Moreover, the N1 attention effect was reduced when the preceding stimulus contained elements in the attended field. It was concluded that modulations of the N1 and P1 components in these experiments represent different aspects of visual spatial attention: N1 may represent the orienting of attention to a task-relevant stimulus, whereas P1 may represent a facilitation of early sensory processing for items presented to a location where attention is already focused.     

Large,virus-like,sinuous tubules in the endoplasmic reticulum of human neurons: report from a case of encephalopathy and brief critical review

We report a case of a rapidly progressive, fatal non-inflammatory demyelinating disease, distinct from multiple sclerosis and lysosomal disorders, in a patient with progressive dementia. Electron microscopy of stereotactic brain biopsy samples revealed the presence in neurons of sinuous, double-walled cylindrical membranous structures within the cisterns of the endoplasmic reticulum. These structures were 75–80 nm in overall diameter, up to 1.5 mm long and had a 40- to 45-nm diameter core. The possibility that they might be viruses of the Filoviridae or Paramyxoviridae families was considered, but the inclusions differed in key morphological aspects from members of both virus families and there were no supporting clinical or pathological data. Neither was it possible to assign the structures to any other known virus family on the basis of their morphology. Such inclusions have been the subject of only three published reports over the past 20 years. Evidence suggests that they may be confined to human central nervous system neurons, but occur in unrelated disorders (Alzheimer’s disease, amyotrophic lateral sclerosis, meningoencephalitis, low-pressure hydrocephalus, demyelination). The possibility that they are formed in certain neurons by an abnormal internal budding process, as a response to a variety of pathological insults, is considered most likely, although an infectious origin (such as an unrecognised virus with variable clinical effect) cannot be ruled out. Received: 29 November 1995 / Revised, accepted: 8 March 1996     

Nerve endings of the wrist joint: a preliminary report of the dorsal radiocarpal ligament.

As part of an investigation of the articular nerve ending populations in the wrist joint capsule associated with the anterior and posterior interosseous nerves, this study addresses the nerve ending population in the dorsal radiocarpal ligament. The ligaments were harvested from four wrists of two fresh cadavers within 12 h of death. Tissues were fixed, cryostat sectioned, and processed for fluorescence immunohistochemistry using antibody to protein gene product 9.5 (PGP 9.5), a general or pan neuronal marker, and a secondary antibody conjugated to a fluorescent tag (Alexa Fluor 488). The sections were evaluated with a confocal laser microscope and an image analyzer. Labeled nerve endings were mapped, measured, and categorized. Type I (Ruffini-like ending), Type III (Golgi-like tendon organ) and Type IV (noncorpuscular) nerve endings could be identified in all four DRC ligaments, with Types I and IV dominating. These receptors were distributed primarily over the superficial two thirds of the ligament (>80%), and near the bony attachments (>70%). The dorsal radiocarpal ligament has a rich sensory innervation from the posterior interosseous nerve terminating in nerve endings located in the superficial two-thirds of the ligaments, primarily near bony attachment sites.     

Serum ultrafiltration for the elimination of endogenous interfering substances in creatinine determination

Serum, at neutral pH, was submitted to a simple filtration, using centrifugation in the disposable Centrisart. The ultrafiltrate was similar to serum in its creatinine content but was virtually free from proteins, including protein-bound bilirubin, haemoglobin and lipoproteins. The creatinine concentrations of anicteric serum specimens and the corresponding ultrafiltrates as determined with Jaffé and enzymic procedures show a high correlation and are convertible. With icteric sera the negative interference effect of bilirubin in a particular analytical procedure can be quantified using ultrafiltrate as the reference. It is suggested that ultrafiltration is useful in selected cases for eliminating elevated concentrations of bilirubin, haemoglobin and turbidity, which would interfere in the direct creatinine determination. Relative to the continuous flow methods with dialysis of the analyte, direct methods for creatinine are more susceptible to interference by endogenous factors like hyperbilirubinaemia, hypertriglyceridaemia and haemolysis (1). The negative interference by bilirubin is of special importance, since it interferes in some modifications of the kinetic Jaffé method (2) and in the chromogenic enzymatic method (3). As a simple alternative, we evaluated the use of serum ultrafiltrate for the accurate determination of creatinine by the Jaffé and enzymatic methods, free from interfering by the high-molecular serum matrix and compounds bound to it.     

Developmental progress in Duchenne muscular dystrophy: lessons for earlier detection.

OBJECTIVE: To address the issue of diagnostic delay in Duchenne Muscular Dystrophy (DMD) using developmental data from a cohort of affected boys detected by newborn screening and data on the diagnostic pathways of a group of boys diagnosed clinically. DESIGN: Quantitative and semi-qualitative. SETTING: Primary care. SUBJECTS: 1. Cohort of boys diagnosed by newborn screening (NBS cohort), 2. Group of mothers whose sons were diagnosed clinically (LCD group) Interventions. NBS cohort: (a) Developmental milestones, (b) Griffiths assessment, (c) clinic letters, (d) family case studies. LCD group: semi-structured interview. MAIN OUTCOME MEASURE: 1. The effectiveness of previously proposed strategies for the earlier clinical diagnosis of DMD. 2. Diagnostic pathways of the LCD group. Factors contributing to diagnostic delay in the LCD group. RESULTS: 1. Previously proposed strategies for earlier diagnosis would have had limited effectiveness in detecting the NBS cohort. 2. Diagnostic delay continues because: (a) initial observations are usually non-specific and made by the family, (b) age of presentation and presenting symptoms are highly variable, (c) first concerns are usually expressed to the primary care team who are less likely to recognise the early indicators, (d) early locomotor symptoms could suggest an orthopaedic rather than a paediatric referral. CONCLUSIONS: The identification and implementation of an effective screening tool to reduce diagnostic delay is more complex than previously portrayed. In the light of this evidence service providers need to ask whether newborn screening is the only feasible solution to diagnostic delay.