Scattered-light imaging in vivo tracks fast and slow processes of neurophysiological activation.

We imaged fast optical changes associated with evoked neural activation in the dorsal brainstem of anesthetized rats, using a novel imaging device. The imager consisted of a gradient-index (GRIN) lens, a microscope objective, and a miniature charged-coupled device (CCD) video camera. We placed the probe in contact with tissue above cardiorespiratory areas of the nucleus of the solitary tract and illuminated the tissue with 780-nm light through flexible fibers around the probe perimeter. The focus depth was adjusted by moving the camera and microscope objective relative to the fixed GRIN lens. Back-scattered light images were relayed through the GRIN lens to the CCD camera. Video frames were digitized at 100 frames per second, along with tracheal pressure, arterial blood pressure, and electrocardiogram signals recorded at 1 kHz per channel. A macroelectrode placed under the GRIN lens recorded field potentials from the imaged area. Aortic, vagal, and superior laryngeal nerves were dissected free of surrounding tissue within the neck. Separate shocks to each dissected nerve elicited evoked electrical responses and caused localized optical activity patterns. The optical response was modeled by four distinct temporal components corresponding to putative physical mechanisms underlying scattered light changes. Region-of-interest analysis revealed image areas which were dominated by one or more of the different time-course components, some of which were also optimally recorded at different tissue depths. Two slow optical components appear to correspond to hemodynamic responses to metabolic demand associated with activation. Two fast optical components paralleled electrical evoked responses.     

Calprotectin as a marker of inflammation in cystic fibrosis

Calprotectin is an abundant neutrophil cytosolic protein released during neutrophil activation or death. The use of plasma calprotectin concentration as a marker of pulmonary inflammation was tested in 31 children with cystic fibrosis, none of whom was acutely unwell or pyrexic. Twenty three were receiving antibiotics, 21 had positive sputum cultures, but none of the traditional tests clearly diagnosed ongoing infection. Plasma calprotectin was significantly higher in the cystic fibrosis group than in matched controls. Sixteen children with cystic fibrosis had values above the control range (320-1570 micrograms/l). Their chest radiograph Northern score, an index of accumulated pulmonary involvement, and their plasma copper, an index of acute phase response, both correlated with plasma calprotectin. Plasma gamma-glutamyltransferase also correlated weakly with plasma calprotectin: thus, hepatic pathology may be a confounding variable. However, the data still suggested that plasma calprotectin is a better index of inflammation than the traditional indices in general use.     

Fluoroquinolones protective against cephalosporin resistance in gram-negative nosocomial pathogens

In a matched case-control study, we studied the effect of prior receipt of fluoroquinolones on isolation of three third-generation cephalosporin-resistant gram-negative nosocomial pathogens. Two hundred eighty-two cases with a third-generation cephalosporin-resistant pathogen (203 with Enterobacter spp., 50 with Pseudomonas aeruginosa, and 29 with Klebsiella pneumoniae) were matched on length of stay to controls in a 1:2 ratio. Case-patients and controls were similar in age (mean 62 years) and sex (54% male). Variables predicting third-generation cephalosporin resistance were surgery (p = 0.005); intensive care unit stay (p < 0.001); and receipt of a b-lactam/b-lactamase inhibitor (p < 0.001), a ureidopenicillin (p = 0.002), or a third-generation cephalosporin (p < 0.001). Receipt of a fluoroquinolone was protective against isolation of a third-generation cephalosporin-resistant pathogen (p = 0.005). Interventional studies are required to determine whether replacing third-generation cephalosporins with fluoroquinolones will be effective in reducing cephalosporin resistance and the effect of such interventions on fluoroquinolone resistance.     

Growth Hormone and Prolactin Secretion after External Cranial Irradiation for Extrasellar Tumours

Background

Deficiency of one or more anterior pituitary hormones may follow treatment with external radiation when hypothalamo-pituitary axis lies within the field of radiation. Patients with brain tumours who are treated with radiation frequently have growth hormone (GH) deficiency, other neuro-endocrine abnormalities are presumed to be uncommon. The present study has been undertaken with the aim to study GH and prolactin secretion, their relationship with dose of radiotherapy and duration after radiotherapy in patients who have received extracranial radiation for extrasellar tumours.

Method

In this study, 96 patients who underwent cranial radiation before 12 months, were evaluated. Basal 8 a.m. venous blood samples were taken for estimation of prolactin and GH. Insulin tolerance test was performed for stimulated GH levels.

Result

GH deficiency was present in 59% patients. Isolated GH deficiency was present in 12 (21%) cases, whereas others had associated hormone deficiency. Height percentiles of prepubertal and pubertal patients were 10^th to 25^th (-1.5 to -0.5SD). Patients with isolated GH deficiency had received significantly higher radiation dose than normal pituitary function (5795 ± 24 vs 4908 ± 71, p=0.001). Proportion of patients with GH deficiency increased with increasing dose of radiation (p=0.12), fractional dose of radiation (p=0.08) and increasing duration after radiotherapy (p=0.038). GH levels among all decreased significantly with increasing dose of radiation (p=0.02). Hyperprolactinemia was present in 21% of cases. GH deficiency is more common with lower (<5ng/ml) and higher (>15ng/ml) prolactin levels.

Conclusion

GH deficiency is common after extracranial radiation for extrasellar tumours. GH deficiency is related to dose of radiation, fraction of radiation, and duration after radiotherapy. All prepubertal and pubertal patients with GH deficiency had their height percentile within normal range. Relation of prolactin and GH deficiency indicates that radiation affects both hypothalamus and pituitary.Key Words: Cranial radiation, Growth hormone deficiency, Hyperprolactinemia     

Target Gland Dysfunction Following External Cranial Radiation for Extrasellar Tumours

Background

Diseases of the pituitary gland manifest as increased or decreased production of one or more of these hormones that in turn trigger a series of secondary hormonal changes in target glands (Thyroid, Adrenal and Gonad). Dysfunction of target glands may follow treatment with external radiation when hypothalamo-pituitary axis lies within the field of radiation. The present study has been undertaken with the aim to study target gland dysfunction and their relationship with dose of radiotherapy and duration after radiotherapy in patients who have received extracranial radiation for extrasellar tumours.

Methods

In this study, 96 patients who underwent cranial radiation 12 months ago were evaluated. Basal 8 am venous blood samples were taken for estimation of triiodothyronine (T₃), thyroxin (T₄), thyrotropin stimulating hormone (TSH) and basal cortisol estimation. Pooled samples (three samples taken 20 minutes apart and pooled together) were taken for LH, FSH and testosterone (TE) estimation. Insulin tolerance test was performed for stimulated cortisol levels.

Results

Target gland dysfunction was present in 72 (75%) patients. Hypogonadism was present in 48 (53%) of post-pubertal patients. 36% of male patients had hypogonadism whereas 100% of female patients had hypogonadism. Patients with hypogonadism were older, received higher doses of radiation and evaluated earlier after radiotherapy than without hypogonadism. Serum testosterone level declined significantly with increasing doses of radiation. Hypoadrenalism was present in 44 patients (46%). There was no significant difference of age, radiation dose and radiation fraction among patients with or without adrenal insufficiency. Proportion of patients with hypoadrenalism increased with increasing duration after radiotherapy. Hypothyroidism was present in 12 patients (13%). Proportion of patients with hypothyroidism doubled with increasing dose of radiation. Serum T₃ level declined significantly with increasing doses of radiation. Patients with hypothyroidism had significantly low T₃ and T₄ level, but significantly higher TSH and basal and peak cortisol levels than patients without hypothyroidism.

Conclusion

Target gland dysfunction is common after extracranial radiation for extrasellar tumours. Hypogonadism was the commonest followed by hypoadrenalism and hypothyroidism. Target gland dysfunction was related to age, radiation dose and duration after radiotherapy, but not with fraction of radiation.Key Words: Adrenal insufficiency, Cranial radiation, Hypogonadism, Hypothyroidism     

姜黄素促进损伤骨骼肌修复

目的:研究姜黄素促进损伤骨骼肌修复的功能.方法:制作小鼠胫骨前肌实验性损伤模型,实验小鼠分别肌注和口服姜黄素,以组织学指标观察姜黄素体内促进损伤骨骼肌的修复功能.采用MTT和流析细胞分析技术观察姜黄素对骨骼肌成肌细胞的作用及可能的信号传导通路.结果:实验的小鼠肌肉伤口区新生肌纤维显著多于对照组.姜黄素无明显促C2C12细胞增殖,但能促进C2C12细胞融合而分化成肌纤维;姜黄素能抑制C2C12细胞NFκB反应因子的转活,而对c-Myc和CRE通路反应因子没有显著影响.大剂量使用姜黄素未见急性毒性反应.结论:姜黄素能通过促进骨骼肌干细胞的分化而促进损伤骨骼肌的修复.