Normal cerebral perfusion measurements using arterial spin labeling: reproducibility, stability, and age and gender effects.

Before meaningful conclusions can be drawn from clinical measures of cerebral blood perfusion, the precision of the measurement must be determined and set in the context of inter- and intrasubject sources of variability. This work establishes the reproducibility of perfusion measurements using the noninvasive MRI technique of continuous arterial spin labeling (CASL). Perfusion was measured in 34 healthy normal subjects. Intersubject variability was assessed, and age and gender contributions were estimated. Intersubject variation was found to be large, with up to 100% perfusion difference for subjects of the same age and gender. Repeated measurements in one subject showed that perfusion remains remarkably stable in the short term when compared with intersubject variation and the large capacity for perfusion change in the brain. A significant decrease in the ratio of gray-matter to white-matter perfusion was found with increasing age (0.79% per year (P < 0.0005)). This appears to be due mainly to a reduction in gray-matter perfusion, which was found to decrease by 0.45% per year (P = 0.04). Regional analysis suggested that the gray-matter age-related changes were predominantly localized in the frontal cortex. Whole-brain perfusion was 13% higher (P = 0.02) in females compared to males.     

Energy expenditure and body composition in children with Crohn's disease: effect of enteral nutrition and treatment with prednisolone

Background—Malnutrition and growth retardation arecommon complications of Crohn's disease in children. The contributionof resting energy expenditure (REE) to malnutrition is unclear.
Aims—To characterise the REE and body compositionin children with Crohn's disease and compare them with normal controlsand patients with anorexia nervosa; to compare the effects ofprednisolone and enteral nutrition on energy expenditure and body composition.
Subjects—Twenty four children with Crohn'sdisease, 19 malnourished females with anorexia nervosa, and 22 healthycontrol subjects were studied.
Methods—In children with Crohn's diseasemeasurements were done when the disease was acute and repeated at oneand three months after treatment with either prednisolone or enteralnutrition. Resting energy expenditure was measured by indirectcalorimetry and body composition by anthropometry, bioelectricalimpedance analysis, total body potassium,H₂¹⁸O, and bromide space studies.
Results—Body weight and ideal body weight weresignificantly lower in patients with Crohn's disease than in healthycontrols. Lean tissue was depleted and there was an increase inextracellular water. Per unit of lean body mass, there was nodifference between REE in patients with Crohn's disease and controls,whereas patients with anorexia nervosa had significantly reduced REE.With enteral nutrition all body compartments and REE increasedsignificantly (p<0.001). In a subgroup of age-matched men there was asignificant increase in height after three months of enteral nutritioncompared with prednisolone (p<0.01). Those treated with steroids didnot show a significant change in height but did show an increase in allbody compartments. However, intracellular water as well as lean bodymass accretion were significantly higher in the enteral nutrition groupthan in the prednisolone group.
Conclusions—Despite being malnourished, childrenwith Crohn's disease fail to adapt their REE per unit of lean bodymass. This might be a factor contributing to their malnutrition. Lean tissue accretion is higher in patients treated with enteral nutrition than in those treated with prednisolone.

Keywords:Crohn's disease; resting energy expenditure; bodycomposition; anorexia nervosa; prednisolone; enteral nutrition

     

Cell-type-specific excitatory and inhibitory circuits involving primary afferents in the substantia gelatinosa of the rat spinal dorsal horn in vitro

The substantia gelatinosa (SG) of the spinal dorsal horn shows significant morphological heterogeneity and receives primary afferent input predominantly from Aδ- and C-fibres. Despite numerous anatomical and physiological studies, correlation between morphology and functional connectivity, particularly in terms of inhibitory inputs, remains elusive. To compare excitatory and inhibitory synaptic inputs on individual SG neurones with morphology, we performed whole-cell recordings with Neurobiotin-filled-pipettes in horizontal slices from adult rat spinal cord with attached dorsal roots. Based on dendritic arborization patterns, four major cell types were confirmed: islet, central, radial and vertical cells. Dorsal root stimulation revealed that each class was associated with characteristic synaptic inputs. Islet and central cells had monosynaptic excitatory inputs exclusively from C-afferents. Islet cells received primary-afferent-evoked inhibitory inputs only from Aδ-fibres, while those of central cells were mediated by both Aδ- and C-fibres. In contrast, radial and vertical cells had monosynaptic excitatory inputs from both Aδ- and C-fibres and inhibitory inputs mediated by both fibre types. We further characterized the neurochemical nature of these inhibitory synaptic inputs. The majority of islet, central and vertical cells exhibited GABAergic inhibitory inputs, while almost all radial cells also possessed glycinergic inputs. The present study demonstrates that SG neurones have distinct patterns of excitatory and inhibitory inputs that are related to their morphology. The neurotransmitters responsible for inhibitory inputs to individual SG neurones are also characteristic for different morphological classes. These results make it possible to identify primary afferent circuits associated with particular types of SG neurone.     

Small cell (oat cell) carcinoma of the trachea with endocrine features. Report of a case and results of ultrastructural and immunohistochemical study

Primary small cell (oat cell) carcinoma of the trachea is very rare. We report a case with ultrastructural evidence of endocrine differentiation. Immunoperoxidase staining demonstrated carcinoembryonic antigen and bombesin in the tumor cells.     

Covid-19 Pandemic: Resumption of Orthopedic Care and Medical Education

Covid-19 is a respiratory disease caused by coronavirus 2 (SARS-CoV-2) first identified in Wuhan, China (December 2019). The disease rapidly crossed the barrier of countries, continents and spread globally. Non-pharmaceutical measures such as social distancing, face mask, frequent hand washing and use of sanitizer remained the best available option to prevent the spread of disease. OPD, IPD admissions, elective O. Ts were curtailed. Orthopedic care was only limited to emergency and semi-urgent procedures like necrotizing fasciitis, open fracture, and compartment syndrome. These measures were taken to preserve infrastructure and manpower to manage covid-19 pandemic. The children were thought to have a low susceptibility to covid-19 as compared to an adult. Deferring the patient during pandemic has led to high orthopedic disease burden, morbidity and disease-related sequelae, hence elective care must be resumed with modified hospital infrastructure. Resumption of elective/emergent orthopedic care should be slow, phasic and strategic, much similar to unlocking. Cases must be stratified depending on covid status and severity. Dedicated O.Ts with neutral/negative pressure and HEPA filter for covid positive and suspected patients are to be used. All symptomatic and suspected patients should be investigated for covid-19 by RT-PCR, blood counts and CT scan. Regional anaesthesia should be preferred to General anaesthesia. Power drill/saw/burr/pulse lavage should be minimized to avoid aerosol generation. Postoperatively continuous surveillance and monitoring to be done for covid related symptoms. Medical institutes rapidly shifted to the online mode of education. Blended learning (virtual & physical) and imparting skills have to be continued in post covid phase with equitable distribution of teaching hours to students of different years.     

Ondansetron versus placebo for the control of nausea and vomiting during Caesarean section under spinal anaesthesia

This prospective, randomised, placebo-controlled, double-blind study was performed to evaluate the effects of ondansetron on nausea and vomiting during elective Caesarean section under spinal anaesthesia. Seventy-four full-term parturients were studied. After umbilical-cord clamping, ondansetron 4 mg or 0.9% saline was injected intravenously and the study period continued for 2 h. The severity of nausea was graded from 0 = none to 10 = maximum, while that of vomiting was graded from single = once per min to continuous = multiple per min. The incidence of vomiting was lower following ondansetron (36%) compared with the control group (58%, p < 0.028). Neither the severity of vomiting nor the incidence of nausea was influenced by ondansetron. However, for those who experienced nausea, ondansetron reduced its severity (p = 0.05). We conclude that the intra-operative administration of 4 mg ondansetron intravenously during Caesarean section under spinal anaesthesia significantly reduces the incidence of vomiting and the severity of nausea.