Effects of consumption of contaminated feed with 2,4-dichlorophenoxyacetic acid (2,4-D) on the rat tibia: analysis by Raman spectroscopy and mechanical properties

Lasers in Medical Science - Studies reported the harmful effects of 2,4-D on body tissues, provoking changes in the anatomy and physiology of the kidneys, liver, and testicles. Thus, the objective...     

Myocardial metabolism during aortic valve replacement. II. Bolus infusion of cold blood for cardioplegia

Myocardial energy metabolism during hypothermic potassium cardioplegia with blood as the cardioplegia vehicle, given in one or two bolus doses, was studied in eight patients undergoing aortic valve replacement. Myocardial biopsies were taken from the left ventricle 10 min after aortic cross-clamping (a.c.) and immediately before declamping (d.c.) and were analyzed for ATP, creatine phosphate (CP), creatine (C) and lactate. The interindividual range of myocardial temperature was 11-19 degrees C at 10 min a.c. and 11-25 degrees C immediately before d.c. The myocardial ATP concentration fell (17.2 +/- 5.7-12.8 +/- 2.8 mmol X kg-1 dry muscle), the lactate concentration rose (64.7 +/- 35.8-136 +/- 33.8 mmol X kg-1 d.m.) and the total creatine pool (CP + C) was unchanged. Hypothermic blood cardioplegia conferred fairly good initial protection of the myocardium, but the reduction in ATP and the great lactate accumulation towards the end of cardioplegia, especially in patients with myocardial temperature reaching 19-25 degrees C, indicates that such protection is adequate only if the myocardial temperature is maintained between 11 and 18 degrees C.     

Noxious stimuli excite neurons in nucleus submedius of the normal and arthritic rat

Anatomical studies have revealed the existence of an ascending pathway originating in the spinal cord and medullary dorsal horn, relaying in nucleus submedius (Sm) in medial thalamus and terminating in ventrolateral orbital cortex. It has been suggested that this pathway may be involved in the transmission of nociceptive information. In the present study extracellular recordings were obtained from neurons in Sm of anesthetized arthritic and normal rats. Mechanical and thermal stimuli were delivered to various regions of the body to determine the types of somatic stimuli which could activate Sm neurons. Over 40% of the 146 neurons studied responded to somatic stimuli. In the normal rats only high intensity mechanical and thermal stimuli were effective in inducing responses. In the arthritic rats lower intensity mechanical stimuli, joint movements and high intensity thermal stimuli were effective. Such stimuli produce nociceptive reactions in the freely moving arthritic rat. Almost all the responses were excitatory and generally lasted the entire duration of the 15-s stimuli employed. In some cases after-discharges were present. The receptive fields of the neurons were in almost all cases large and bilateral. These findings support the hypothesis that Sm may be involved in mediating the affective-motivational aspects of pain.     

Rare associations of dens invaginatus and mesiodens.

Dens invaginatus is a developmental variation resulting from an alteration in the normal growth pattern of the dental papilla. Synonyms of this disturbance include dens in dente, invaginated odontome, tooth inclusion, and dentoid in dente. Radiographically, it is observed as infolding of a radiopaque ribbon-like structure, with equal density as enamel, extending from the cingulum into the root canal and sometimes reaching the root apex, assigning the appearance of a small tooth within the coronal pulp cavity. This article presents 2 case reports. The first describes an 8-year-old girl with dens invaginatus in a mesiodens; the second report describes a 16-year-old boy presenting with 2 mesiodens, both associated with dens invaginatus.     

Growth hormone effects on hypertrophic scar formation: a randomized controlled trial of 62 burned children

The hypercatabolism after massive pediatric burns has been effectively treated with recombinant human growth hormone, an anabolic agent that stimulates protein synthesis and abrogates growth arrest. While experimental studies have shown increased potential for fibrosis induced by growth hormone therapy, adverse effects on human scars have not been investigated. Our aim was to evaluate hypertrophic scar formation in 62 patients randomized to receive injections of 0.05 mg/kg/day of recombinant human growth hormone or placebo, from discharge until 1 year after burn. Scar scales were used to evaluate scar-severity at discharge, 6, 9, 12, and 18-24 months after burn, by three observers blinded to treatment. Computer-assisted planimetry allowed quantification of percentage of hypertrophic scar formation. Types I and III collagens were localized and quantified in scars and normal skin of patients from both groups, using immunohistochemistry with confocal laser microscopy analysis. Insulin-like growth factor-1 blood levels helped assess compliance. Statistical analysis showed that scar hypertrophy significantly increased from 6 to 12 months after injury in both groups, while decreasing at 18-24 months postburn. Types I and III collagens were statistically increased in the reticular layer of scars from both groups when compared to paired normal skin. Insulin-like growth factor-1 was significantly increased in the recombinant human growth factor-treated group. No differences were seen when recombinant human growth factor and control groups were compared using the scar scales, planimetry, or immunohistochemistry. We concluded that recombinant human growth hormone therapy did not adversely affect scar formation and should not contraindicate the administration of recombinant human growth hormone as a therapeutic approach to severely burned children.     

Somatic responses of ventrobasal thalamic neurones in polyarthritic rats

Rats rendered polyarthritic by injection ofMycobacterium butyricum into the tail were used as a model for the study of ‘chronic pain’.In such rats unitary responses of ventrobasal thalamic neurons to somatic stimulations were dramatically modified by comparison to those described in normal rats investigated in the same anaesthetic conditions.

(1) Only the neurons with receptive fields located on inflamed areas (168/194 in 33 rats) have been considered in this study. 27/168 activated only by brushing displayed the classical properties of lemniscal responses; only 20/168 were activated exclusively by intense cutaneous stimuli and 13/168 already activated by light cutaneous stimuli had enhanced discharges when the stimulus intensity was increased. By contrast numerous units (108/168) were excited by mild stimulations applied to the joints or to adjacent cutaneous areas (82 were driven by joint movement and/or mild lateral pressure on the articulation, 26 by brushing the overlapping skin); these responses presented atypical characteristics and displayed unusual patterns with very long afterdischarges of duration several times that of the stimulus.

(2) In 20 additional arthritic rats, responses to transcutaneous electrical stimulation (TES) and/or to noxious heat, were obtained for 34 neurones responding to joint stimuli.

(a) 16 of 18 neurones tested with transcutaneous electrical stimulation had latencies of 25–100 ms, and thresholds of 1–4 mA (width of shock 2 ms). (b) Neurones activated by joint stimuli frequently responded to noxious heat (radiant or waterbath). Initially, their response thresholds tested in 16 neurones were higher by about 4°C than those of ‘noxious’ VB neurones in normal rats; however, following sensitization to heat, thresholds were decreased by 4°C. For 8 neurones there was a linear relation between stimulus intensity and responses.

(3) Several different factors which could explain the important modifications of neuronal responses in VB complex of arthritic rats by comparison with normal are proposed in the discussion.

High-resolution Spectral Domain Optical Coherence Tomography Findings in Multifocal Vitelliform Macular Dystrophy

We describe the abnormalities seen in the mid periphery and posterior pole of two patients with multifocal vitelliform macular distrophy as evaluated by high-definition spectral domain optical coherence tomography (HD-OCT). In patient 1, HD-OCT scans revealed, in the central area, a thicker and more reflective layer compared with the normal macula, located between the retinal pigment epitelium and the interface of the inner segment /outer segment, corresponding to the Verhoeff‘s membrane. Moreover, HD-OCT macular scans, as well as C-scans, revealed a slight hyper-reflective lesion just above an area of reduced reflectivity between the photoreceptor layer (interface of the inner segment and outer segment) and the Verhoeff‘s membrane. In patient 2, on HD-OCT macular scans, the layer corresponding to the interface of inner segment and outer segment of the photoreceptor, and the Verhoeff's membrane, appeared disrupted, whereas the retinal pigment epithelium layer appeared preserved. On the other hand, in both patient 1 and 2, the clinically evident vitelliform lesions outside the macular area appeared on HD-OCT scans either as small focal hyper-reflective lesions at the level of the retinal pigment epithelium/photoreceptor complex, either as a more pronounced diffuse thickening of the retinal pigment epithelium/photoreceptor complex, facing the deposition of lipofuscin reported on the histopathologic examination. These new findings would help in a further understanding of multifocal vitelliform macular distrophy.     

O Uso da Escala de Borg na Percepção do Esforço em Manobras de Reanimação Cardiopulmonar

BackgroundA cardiopulmonary arrest is a critical event whose survival rate is related to the quality of resuscitation maneuvers combined with the use of technology. It is important to understand the perception of fatigue during this procedure, aiming to improve the effectiveness of compressions to increase the chances of survival.ObjectivesTo apply the Borg rating of perceived exertion scale (Borg scale) to analyze the exertion perceived by nurses during cardiopulmonary resuscitation maneuvers using a feedback device.MethodsExperimental study with a randomized distribution of nurses in a teaching hospital. Perceived exertion during simulated cardiopulmonary resuscitation with/without a feedback device was assessed using the Borg scale. The statistical significance level of 5% was adopted.Results69 nurses working in critical and non-critical adult care units were included. Perceived exertion and heart rate were lower in the intervention group (p<0.001), influenced by the feedback device, with no significant difference between critical and non-critical units.ConclusionsThe Borg scale proved to be adequate for the proposed objectives. The feedback device contributed to lower exertion and heart rate reduction during resuscitation maneuvers. The low cost and ease of application favor its use during training and real-time resuscitation attempts to assess performance using a feedback device to reduce exertion and perception of fatigue. It allows reflection on the intervening factors and resources that can influence the quality of resuscitation attempts and the chances of survival.