Are lasers superior to lights in the photoepilation of Fitzpatrick V and VI skin types? – A comparison between Nd:YAG laser and intense pulsed light

Background and objectives: There are no large volume comparative studies available to compare the efficacy of lasers over lights for hair removal in Fitzpatrick V and VI skin types. This study is designed to compare the efficacy of Nd:YAG laser versus IPL in the darker skin types. Study design/materials and methods: Thirty-nine patients included in Group-1 were treated with Nd:YAG and 31 in Group-2 with IPL. Both groups received 5 sessions of treatment. The hair counts were assessed using digital photography and manual counting method before and after treatment and the results were analysed. Patient satisfaction scores and pain scores were recorded in each session and compared. Results: Mean hair reduction in the IPL group was 25.70 and Nd:YAG group was 24.12 (95% CI). In the Nd:YAG group, 59% of subjects had burning sensation while the figure was 32.3% in IPL group. Burning was less in IPL group (p < 0.023). There were no statistically significant differences noticed regarding hyperpigmentation in both the groups (p < 0.115). Conclusion: Both Nd:YAG and IPL are equally effective for epilation of the darker skin types. Nd:YAG is associated with mild burning sensation in a significant number of patients. Patient satisfaction scores were comparable in both the groups.     

Histopathologic and Microbiologic Aspects of Ventilator-associated Pneumonia

Background: The relationship between microbiology and histology in patients with ventilator-associated pneumonia has been sparsely described.

Methods: Twenty-five patients who died in the intensive care unit after their lungs had been mechanically ventilated for 72 h were studied. Twenty of the 25 died with clinical suspicion of pulmonary infection. A total of 375 immediate postmortem pulmonary biopsies were obtained after death and processed for quantitative microbiology and histology. Four evolutionary stages of pneumonia were defined: early, intermediate, advanced, and resolution.

Results: At least one specimen with histologic evidence of pneumonia was found in all but two patients (92%). Histologic pneumonia was a widespread and frequent process (46% of biopsies examined) involving predominantly the lower lobes (55% of all biopsies with pneumonia) and showing different histopathologic stages of progression coexisting in the same lung lobes. Lung cultures were frequently polymicrobial (149 of 375, 40% of the pulmonary biopsy cultures, and 20 of 25, 80% of the cases) and not always yielding the same pathogen (19 microorganisms) when comparing one lung to the other. Histopathology and microbiologic biopsy cultures showed a weak relationship (28% and 49% of species had counts greater or equal to 103 cfu/g in samples without pneumonia from patients with and without prior antibiotic treatment, respectively). Histopathologic evolutionary stages were not associated with any differences in quantitative culture results of pulmonary biopsies, independently of prior administration of antibiotics. Higher bacterial concentrations of biopsy cultures were associated with the absence of prior antibiotic treatment.     

Experimental Lead Neuropathy: Ultrastructural And Molecular Changes In The Rat Sciatic Nerve

Experimental lead intoxication is an important model for the study of cellular and molecular mechanisms of segmental demyelination in peripheral nerve. In this report we have compared pathological changes with the molecular and immunohistochemical expression of the proteins of compact and non-compact myelin in the demyelinating neuropathy induced in Sprague-Dawley rats after chronic administration (3 and 6 months) of lead acetate in drinking water. All the rats underwent the neurophysiological determination of the conduction velocity in the tail nerve at baseline and 3, 4.5 and 6 months after the beginning of the lead acetate administration. At the end of the treatment period the rats were sacrificed and sciatic nerve specimens were obtained. The neurophysiological study demonstrated a significant decrease in the nerve conduction velocity, which was already evident at the first determination (3 months) and persisted along the entire experiment. The neurophysiological results were in agreement with the pathological observations performed in the sciatic nerve, where several large demyelinated fibers were observed in the lead-intoxicated rats. Northern and Western blot analysis demonstrated that steady state mRNA and protein levels for P0, MBP, PMP22 and PLP were not changed comparing treated and control rats. Immunohistochemistry on teased fibers revealed that those proteins were distributed in areas of compact myelin along the internodes. In control fibers, as expected, MAG was found in the periaxonal cytoplasm, at nodes of Ranvier, and in the Schmidt-Lanterman incisures. In lead neuropathy, MAG was still limited to discrete regions, but the intensity of staining was reduced, in accordance with changes of paranodal structures. Immunohistochemical localization of other proteins of non-compacted myelin, including connexin-32, E-cadherin and β-catenin was also examined. Our data further suggest that chronic lead intoxication in the rat produces segmental demyelination due primarily to Schwann cell dysfunction.     

Regulation of corticotropin-releasing hormone receptors and hypothalamic pituitary adrenal axis responsiveness during cold stress

The relationship between pituitary corticotropin-releasing hormone (CRH) receptor changes and corticotrope responsiveness was studied during chronic cold stress. Exposure of rats to 4°C caused a gradual increase in plasma adrenocorticotropic hormone (ACTH), reaching 3-fold over the basal levels by 6 h (P< 0.005), followed by a reduction to levels only 1.3-fold over basal by 60 h. Plasma corticosterone was significantly increased after 1 h (P<0.005) and remained elevated for up to the 60 h cold exposure (P < 0.005). No significant changes in plasma thyroid-stimulating hormone, prolactin, growth hormone or vasopressin were observed at 60 h of cold exposure. CRH receptor concentration in the anterior pituitary was unchanged after 18 or 60 h cold stress, whereas in neurointermediate lobe membranes was markedly elevated. Autoradiographic analysis of pituitary CRH receptors confirmed that the increase in CRH binding was confined to the intermediate pituitary. CRH receptor levels in membranes from two brain areas, frontal cortex and amygdala, were unchanged following 60 h cold stress. The areas under the curve for the plasma ACTH and corticosterone levels following an injection of 10μg/kg ovine CRH in conscious rats, were of similar magnitude in control and 60 h cold exposed rats. Plasma ACTH responses to ether stress were significantly higher in rats exposed to cold for 60 h than in controls. In the intermediate pituitary, basal ß-endorphin/lipotropin release from isolated intermediate pituitary cells was significantly lower in cold stressed rats, and despite the increase in CRH receptors CRH-stimulated values were not higher than in controls. Following 60 h cold exposure, immunoreactive CRH content was decreased in neurointermediate pituitary extracts, while it was slightly increased in the median eminence. Exposure to ether for 5 min resulted in a significant decrease in immunoreactive CRH in the median eminence of cold stressed rats, but not in the controls. The data show a lack of correlation between changes in CRH receptor levels and responsiveness of the corticotrope in the anterior and intermediate pituitary lobes. This suggests that postreceptor events and interaction of CRH with other regulators of ACTH secretion are more likely to account for the changes in pituitary responsiveness during chronic stress.