Morphology of human fetal enteric neurons: A comparative study of different segments of the colon

OBJECTIVES

The Enteric Nervous System (ENS) present in the wall of the gut is currently being explored because of its influence on the gut and beyond. In this context, the morphology of developing ENS has not been completely understood in humans due to lack of adequate literature. The aim of the present study was to observe the morphology of the enteric neurons in the human fetal colon and compare the findings in ascending colon a midgut derivative and descending colon a hindgut derivative at various weeks of gestation (WG).

MATERIAL AND METHODS

Tissue samples from 15 aborted fetuses (11 WG to 2 months postnatal) were processed for Cresyl violet, H & E staining, and NADPH Diaphorase histochemistry. The morphometric analysis was done by calculating the neuronal number density and neuronal fractional area. The Student t-test; Mann-Whitney test and Wilcoxon signed-rank test were used to analyze the data.

RESULTS

The muscularis externa with two distinct layers was visible as early as 13 WG and the muscularis mucosae was first observed at 18 WG. The size of the myenteric neurons appeared to be larger with increasing weeks of gestation suggesting a process of neuronal maturation. The neuronal number density and neuronal fractional area seemed to be reduced with advancing fetal age. There was no marked difference between the ascending and sigmoid colon. At 23 and 26 WG, a mature pattern of nitrergic innervation was observed.

CONCLUSION

This study is done on human fetal tissue samples unlike previous studies on animal samples to comprehend the morphology of developing ENS. It will aid in understanding the effect of ENS on various neurological disorders.

Neuromuscular variations in the gluteal region - Embryological basis and clinical significance

ABSTRACT

Piriformis, is a key muscle in the gluteal region. Under its lower border sciatic nerve and inferior gluteal nerves exit. During routine educational dissection of the lower limb, bilateral gluteal regions in fifteen cadavers (30 gluteal regions) focusing on the variations of inferior gluteal nerve and sciatic nerve with respect to piriformis muscle were observed in the department of anatomy, All India Institute of Medical Sciences, New Delhi, India. In one of the left sided specimens, inferior gluteal nerve had an abnormal course, piercing superior belly of piriformis muscle instead of emerging through the lower border of it along with variation of the sciatic nerve. The common peroneal component of the sciatic nerve was coming out between the two anomalous tendinous slips of the piriformis muscle, whereas the tibial component, emerged along lower border of the piriformis muscle bilaterally in the same cadaver. In the remaining cadavers, there were no variations of the inferior gluteal nerve with respect to the piriformis muscle. But in another cadaver, there was a similar variation of the sciatic nerve bilaterally. Inferior gluteal and sciatic nerves, when compressed by muscle belly or tendinous slips of the piriformis muscle, may cause lurching gait and sciatica respectively. Knowledge of the different variations of these peripheral nerves with respect to the piriformis muscle is important to clinicians and surgeons for the accurate diagnosis and intervention.

Morphology of enteric glia in colorectal carcinoma: A comparative study of tumor site and its proximal normal margin

OBJECTIVE

Colorectal carcinoma (CRC) is the third most common cancer in the world and fifth most common cancer in India. To understand the extent of perineural invasion (PNI) in CRC it is essential to study the morphology of enteric glial cells (EGCs). The aim of the study was to analyze the numerical density of EGCs and area of myenteric ganglia (MG) in the colonic tissue samples collected from CRC patients.

MATERIAL AND METHODS

Fifteen intraoperative tissue specimens were collected from the tumor site and 2cm proximal to the upper extent of tumor. The samples were divided into four groups: group 1 (n=15): proximal tumor free colonic tissue; group 2 (n=3): well-differentiated; group 3 (n=8): moderately differentiated; group 4 (n=4): poorly differentiated adenocarcinoma. After processing the tissues were subjected to hematoxylin and eosin staining. The anti-S100β and anti-GFAP antibodies were used to observe the EGCs.

RESULTS

In the H&E stained sections the number of myenteric ganglia appeared to be decreasing with increasing grade of adenocarcinoma. Immunostaining showed significant decreasing pattern in the numerical density of EGCs per myenteric ganglion and mean area of myenteric ganglia in relation to the thickness of circular muscle, corresponding to the increasing grades of adenocarcinoma. The morphology of the EGCs remained unaltered in the colonic tissue adjacent to the tumor site.

CONCLUSION

Significant loss of EGCs and neurodegeneration corresponded with the grade of tumor emphasizing on its prognostic value. The PNI was not seen in the clear margin proximal to the tumor site.

Pharmacological treatments for acute respiratory distress syndrome: systematic review

BACKGROUND

Our objective was to systematically review the effect of pharmacological therapies on mortality in patients with acute respiratory distress syndrome (ARDS), focusing on randomized controlled trials (RCTs) published since a previous review in 2004.

METHODS

We updated previous searches and searched OVID versions of MEDLINE, EMBASE and CENTRAL (to January 2013) and proceedings from conferences and bibliographies of included studies. We included RCTs of pharmacologic therapies compared with placebo or no therapy for adult patients with ARDS, using authors' definitions, which reported on mortality (≤ 3 months after randomization). We excluded subgroups of patients with ARDS reported in RCTs enrolling other populations and RCTs of therapies to prevent ARDS, nutritional or fluid interventions, inhaled nitric oxide, therapies coupled to a mechanical ventilation strategy, or oxygen. Two reviewers independently screened citations, selected articles for inclusion, and abstracted clinical and methodological data from included studies with disagreements resolved by a third reviewer. Mortality data were pooled using random-effects models.

RESULTS

From 13461 citations, 58 trials (6635 patients) of 21 classes of medications met selection criteria; 26 trials (3880 patients) were published after 2003. Meta-analyses showed reduced 28-day mortality with a 48-hour infusion of cis-atracurium in early ARDS (relative risk 0.66, 95% confidence interval 0.50 to 0.87; 431 patients, 138 deaths). There was no effect on mortality with granulocyte-macrophage colony stimulating factor, late low-dose methylprednisolone, neutrophil elastase inhibitors, intravenous salbutamol, surfactant, or N-acetylcysteine; each meta-analysis included ≥ 1 trial published after 2003. Seven single trials of other treatments published after 2003 showed no effect. Meta-analysis of older trials of prostaglandin E1 also showed no effect.

CONCLUSION

Effective pharmacotherapy for ARDS remains extremely limited. Cis-atracurium is a promising treatment for early moderate-severe ARDS (using Berlin definition nomenclature) and merits further investigation in a large RCT.