Calbindin immunoreactivity in Purkinje cells of the bullfrog cerebellum during thyroxine-induced metamorphosis

Calbindin-immunoreactive Purkinje cells were identified in the cerebella of frog tadpoles that had been treated with thyroxine to accelerate metamorphosis. The dorsal part of the cerebellar plate contained the full complement of Purkinje cells which were all CaBP-immunoreactive, while in the ventral part of the cerebellum Purkinje cells acquired CaBP-immunoreactivity only after several days of thyroxine treatment. The ventral group of Purkinje cells was separated from the dorsal group by a distinct gap, which is the site of a shallow sulcus in adult frogs. Additionally, following thyroxine treatment, the numbers of CaBP-immunoreactive Purkinje cells in the ventral group were only half the numbers seen in frogs that metamorphosed spontaneously. We suggest that the variation in the CaBP-immunoreactivity of the dorsal and ventral groups of Purkinje cells, along with the gap in the Purkinje cell layer between the two groups, may be indicative of two distinct populations of Purkinje cells, with distinct patterns of generation, maturation, and perhaps, origin and connectivity, in the cerebellum of frogs.     

Altering the biochemical state of individual cultured cells and organelles with ultramicroelectrodes

We describe an efficient technique for the selective chemical and biological manipulation of the contents of individual cells. This technique is based on the electric-field-induced permeabilization (electroporation) in biological membranes using a low-voltage pulse generator and microelectrodes. A spatially highly focused electric field allows introduction of polar cell-impermeant solutes such as fluorescent dyes, fluorogenic reagents, and DNA into single cells. The high spatial resolution of the technique allows for design of, for example, cellular network constructions in which cells in close contact with each other can be made to possess different biochemical, biophysical, and morphological properties. Fluorescein, and fluo-3 (a calcium-sensitive fluorophore), are electroporated into the soma of cultured single progenitor cells derived from adult rat hippocampus. Fluo-3 also is introduced into individual submicrometer diameter processes of thapsigargin-treated progenitor cells, and a plasmid vector cDNA construct (pRAY 1), expressing the green fluorescent protein, is electroporated into cultured single COS 7 cells. At high electric field strengths, observations of dye-transfer into organelles are proposed.     

Human lumbosacral spinal cord interprets loading during stepping

Studies suggest that the human lumbosacral spinal cord can generate steplike oscillating electromyographic (EMG) patterns, but it remains unclear to what degree these efferent patterns depend on the phasic peripheral sensory information associated with bilateral limb movements and loading. We examined the role of sensory information related to lower-extremity weight bearing in modulating the efferent motor patterns of spinal-cord-injured (SCI) subjects during manually assisted stepping on a treadmill. Four nonambulatory subjects, each with a chronic thoracic spinal cord injury, and two nondisabled subjects were studied. The level of loading, EMG patterns, and kinematics of the lower limbs were studied during manually assisted or unassisted stepping on a treadmill with body weight support. The relationships among lumbosacral motor pool activity [soleus (SOL), medial gastrocnemius (MG), and tibialis anterior (TA)], limb load, muscle-tendon length, and velocity of muscle-tendon length change were examined. The EMG mean amplitude of the SOL, MG, and TA was directly related to the peak load per step on the lower limb during locomotion. The effects on the EMG amplitude were qualitatively similar in subjects with normal, partial, or no detectable supraspinal input. Responses were most consistent in the SOL and MG at load levels of < 50% of a subject's body weight. The modulation of the EMG amplitude from the SOL and MG, both across steps and within a step, was more closely associated with limb peak load than muscle-tendon stretch or the velocity of muscle-tendon stretch. Thus stretch reflexes were not the sole source of the phasic EMG activity in flexors and extensors during manually assisted stepping in SCI subjects. The EMG amplitude within a step was highly dependent on the phase of the step cycle regardless of level of load. These data suggest that level of loading on the lower limbs provides cues that enable the human lumbosacral spinal cord to modulate efferent output in a manner that may facilitate the generation of stepping. These data provide a rationale for gait rehabilitation strategies that utilize the level of load-bearing stepping to enhance the locomotor capability of SCI subjects.     

Environmental injuries

Environmental injuries and illnesses can happen in home, work, or recreational settings. The variety and severity of these injuries might require the clinician to call on skills from internal medicine, emergency medicine, and toxicology. Diseases of thermoregulation are hypothermia and hyperthermia. In each instance, treatment is based on the need to restore the patient's core temperature to normal and on monitoring for complications. The victim of a fire might suffer inhalation injury in addition to burns, and it is more likely that the inhalation injury will be fatal. Oxygen deprivation and inhalation of irritant or asphyxiant chemicals contribute to injury. Toxic plants can be the source of poisoning emergencies, especially in children. Misinformation and myths that surround common plants can create diagnostic problems (i.e., which plants really are toxic and require emergency measures). Venomous marine organisms can cause a wide range of injury, from cutaneous eruption to fatal envenomation. Most are encountered in a recreational setting, such as water sports, but keepers of home aquariums are subject to stings from venomous fish. Lightning injury can present many diagnostic and treatment dilemmas. An important point in this regard is that lightning injury and high-voltage electrical injury are different in pathology and require different approaches for treatment. A discussion of electrical, chemical, and thermal burns makes such differences apparent.     

Effects of ischaemia and reperfusion on vasoactive neuropeptide levels in the canine infrarenal aortic revascularization model

Infrarenal aortic cross-clamping is associated with remote vascular events, including myocardial infarction and renal insufficiency. The purpose of this study was to determine whether hindlimb ischaemia and reperfusion associated with infrarenal aortic cross-clamping results in the production of vasoactive regulatory neuropeptides. A canine model of infrarenal aortic cross-clamping was used for the study. Serial blood samples were drawn, prior to, at the time of, and serially following placement of the clamp and subsequent release of the clamp and reperfusion. Ischaemia resulted in increased mean(s.e.m.) plasma levels of neuropeptide Y (NPY) (initial 10.0(1.8) pmol/l versus ischaemia 24.7(2.3) pmol/l, P < 0.001) and vasoactive intestinal polypeptide (VIP) (initial 2.53(0.5) pmol/l versus ischaemia, 7.3(1.3) pmol/l, P < 0.05). Reperfusion produced three-fold elevation of VIP (initial 2.5(0.5) pmol/l versus reperfusion 9.6(1.5) pmol/l, P < 0.001), two-fold elevation in the plasma levels of endothelin-1 (initial 1.3(0.1) pmol/l versus reperfusion maximum 2.5(0.3) pmol/l, P < 0.01) and NPY (initial 10.0(0.8) pmol/l versus reperfusion maximum 23.9(2.3) pmol/l, P < 0.001). Ischaemia and reperfusion did not alter calcitonin gene-related peptide (CGRP) (a potent vasodilator) levels. Endothelin-1 (ET-1) plasma levels were also increased following haemorrhagic shock (initial 1.3(0.1) pmol/l versus exsanguination 3.4(0.4) pmol/l, P < 0.001), but not during ischaemia (initial 1.3(0.1) pmol/l versus ischaemia maximum 1.7(0.2) pmol/l, P = 0.7). It was concluded that vasoactive regulatory peptides are released following ischaemia, reperfusion and shock in the canine infrarenal aortic revascularization model and, therefore could contribute to remote vascular events observed with infrarenal aortic cross-clamping.     

Vasomotor rhinitis and sphenopalatine ganglion block

Quantitative models to explore behavioural disorders are being used increasingly often for health care decision making. Unfortunately, there is a dearth of instruments in Argentina specifically designed for our population, and few researchers have focused on adapting and re-establishing psychometric criteria for instruments proven to be useful in other countries. The aims of this study were to assess the psychometric properties and to develop normative samples for a psychological status symptom inventory, the Symptom Checklist 90 (SCL90). We sought to determine the psychological symptom patterns both in physically healthy community-residing respondents and in physically ill patients in Argentina. The nonpatient sample was a random stratified one, made up of 484 individuals from the general population and representative with regard to gender, age, income and educational level. We also analysed a patient sample that included 105 persons with breast cancer. Results indicated acceptable reliability and validity levels as well as adequate sensitivity to detect differences between patients and nonpatients. We concluded that the SCL90 can be used to measure psychological status in Argentina, and the data presented in this paper can be utilized for comparisons with other similar instruments and with other populations.     

Automated detection of BB pixel clusters in digital fluoroscopic images

Small ball bearings (BBs) are often used to characterize and correct for geometric distortion of x-ray image intensifiers. For quantitative applications the number of BBs required for accurate distortion correction is prohibitively large for manual detection. A method to automatically determine the BB coordinates is described. The technique consists of image segmentation, pixel coalescing and centroid calculation. The dependence of calculated BB coordinates on segmentation threshold was also evaluated and found to be within the uncertainty of measurement.     

Lung transplantation for Williams-Campbell syndrome

Williams-Campbell syndrome is a rare disorder characterized by a deficiency of cartilage in subsegmental bronchi leading to distal airway collapse and bronchiectasis. We report the first case of lung transplantation in a patient with end-stage lung disease secondary to Williams-Campbell syndrome. Although the patient did not have proximal airway collapse prior to transplantation, his posttransplant course was complicated by the development of bronchomalacia of the right and left mainstem bronchi. The patient experienced recurrent pulmonary infections and died of bacterial pneumonia 1 year after transplantation. Autopsy revealed cartilage deficiency in both right and left mainstem bronchi. A hypothesis may be made that a combination of proximal cartilage deficiency and posttransplant airway ischemia led to the development of bronchomalacia after lung transplantation. Thus, in contrast to previous reports, the cartilage deficiency in Williams-Campbell syndrome can involve both proximal and distal airways. Consequently, bilateral sequential lung transplantation may not be an effective therapeutic option in patients with this syndrome.     

Short-term rebound anxiolytic effects and long-term changes in platelet benzodiazepine binding after pentylenetetrazole-kindling in two strains of rat

Although there were no differences in response to an acute injection of pentylenetetrazole (PTZ), there were strain differences in the development of kindled seizures to repeated injections (PTZ; 30 mg/kg 3 times weekly for 13 injections), with Wistar rats reaching stage 4 or 5 of clonic-tonic seizures, but hooded Lister rats reaching only stage 2 or 3 of convulsive waves axially through the body. The strains also reacted differently to a test dose of PTZ (20 mg/kg) one week after the end of kindling, with the Wistar strain showing stage 3 and the Lister strain stage 2 seizures. When the rats were tested 24 h after the end of the kindling injections there was an anxiolytic effect in the social interaction test, in both the low light, familiar and the low light, unfamiliar test conditions that reached significance in the Wistar strain. The Wistar kindled rats showed an anxiolytic effect in the elevated plus-maze test of anxiety when they were tested 24 h after the end of kindling. The anxiolytic effects found 24 h after kindling could not be due to the seizure 24 h earlier, since no changes were found in rats tested 24 h after a single seizure from PTZ (60 mg/kg). When the rats were tested 1 week after the end of kindling there were no changes, compared with vehicle-injected controls, in either test of anxiety. There was no change in benzodiazepine binding in platelets of the kindled Lister rats but there was a significant increase in the kindled Wistar rats 1 week after the end of kindling and also 24 h after a single PTZ seizure. The pattern of increased platelet benzodiazepine binding did not correspond with the time course of rebound anxiolytic effects. However, after kindling it seems that there are long-lasting changes in benzodiazepine binding that are similar to the short-term increases that are found following a single seizure.