Rectal biopsy for Hirschsprung’s disease: a review of techniques,pathology, and complications

Background

Hirschsprung’s disease (HD) is one of the most common congenital anomalies of colorectal function, affecting approximately 1 in 5000 live births, with a 4:1 male predominance. HD is characterized by aganglionosis that is most often limited to the rectosigmoid, but can extend proximally along the colon and, in rare instances, reach into the small intestine. A clinical history of delayed passage of meconium beyond 48 hours after birth, physical exam findings of abdominal distention and vomiting, and a contrast enema demonstrating a transition zone are highly suggestive of HD.

Data sources

We searched databases including PubMed, Google Scholar, and Scopus for the following key words: Hirschsprung’s disease, rectal biopsy, pathology, ganglion cell, nerve trunk hypertrophy, pediatric constipation, and selected publications written in English that were relevant to the scope of this review.

Results

Based on the data presented in the literature, we reviewed 1) biopsy techniques for the diagnosis of Hirschsprung’s disease, addressed inadequate biopsies, and complications from rectal biopsy, and 2) pathologic and histologic interpretation of biopsy specimens for the diagnosis of Hirschsprung’s disease.

Conclusion

A well-executed rectal biopsy with expert pathologic evaluation of the specimen remains the gold standard for the diagnosis of Hirschsprung’s disease and is the subject of this review.

     

Rapid genotyping of the major alleles at the Duffy (FY) blood group locus using real-time fluorescence polymerase chain reaction

The Duffy blood group system has clinical importance due to involvement in transfusion reactions and hemolytic disease of the newborn. Recently, the molecular basis of the two alleles, FY*A and FY*B (125G>A), and the mutation situated in the promoter region of the FY gene (-33T>C), have been elucidated. In order to develop an accurate, easy, and rapid genotyping method, we describe a procedure using the LightCycler. Samples from 53 Caucasian Portuguese blood donors and 7 black, healthy, European individuals were phenotyped with commercial antisera. DNA was extracted from blood samples and the relevant sequences were amplified with the same cycling conditions, using real-time polymerase chain reaction. The melting point of the FY*A allele was 63 degrees C and of the FY*B allele, 55 degrees C. The allele without mutation at the promoter region had a melting point at 64 degrees C and the FY*B silent allele at 58 degrees C. The results in Caucasian individuals were similar to those found in European and American populations. When FY genotyping techniques are necessary, the methodology described is preferable to conventional methods as it is reliable, high speed, and uses small volumes, providing a highly competitive technology for use by a routine laboratory.     

Highly virulent Leptospira borgpetersenii strain characterized in the hamster model

Abstract. A recent study by our group reported the isolation and partial serological and molecular characterization of four Leptospira borgpetersenii serogroup Ballum strains. Here, we reproduced experimental leptospirosis in golden Syrian hamsters (Mesocricetus auratus) and carried out standardization of lethal dose 50% (LD50) of one of these strains (4E). Clinical disease features and histopathologic analyses of tissue lesions were also observed. As results, strain 4E induced lethality in the hamster model with inocula lower than 10 leptospires, and histopathological examination of animals showed typical lesions found in severe leptospirosis. Gross pathological findings were peculiar; animals that died early had more chance of presenting severe jaundice and less chance of presenting pulmonary hemorrhages (P < 0.01). L. borgpetersenii serogroup Ballum has had a considerable growth in human leptospirosis cases in recent years. This strain has now been thoroughly characterized and can be used in more studies, especially evaluations of vaccine candidates.     

Analysis of correlation between cerebrospinal fluid and plasma HIV-1 RNA levels in patients with neurological opportunistic diseases

The question of whether HIV-1 RNA in cerebrospinal fluid (CSF) is derived from viral replication in the central nervous system or simply reflects the transit of infected lymphocytes from the blood compartment has long been a matter of debate. Some studies found no correlation between CSF and plasma viral load, whereas others did. The lack of a correlation between the two compartments suggests that the presence of HIV-1 RNA is not simply due to the passive passage of the virus from blood to CSF but rather due to intrathecal replication. To evaluate the correlation between plasma and CSF HIV-1 RNA levels and to identify situations in which there is no correlation between the two compartments, seventy patients were prospectively studied. The association between CSF and plasma viral load was evaluated in the total population and in subgroups of patients with similar characteristics. A correlation between the CSF and plasma compartments was observed for patients undergoing highly active antiretroviral therapy (HAART), those with a CD4 T lymphocyte count lower than 200 cells/mm3, and those with increased CSF protein content. On the other hand, no correlation was observed for patients without adequate virological control, who had a CD4 count higher than 200 cells/mm3 and who did not use HAART. The correlation between the two compartments observed in some patients suggests that CSF HIV-1 RNA levels may reflect plasma levels in these subjects. In contrast, the lack of a correlation between the two compartments in patients who were not on HAART and who had normal CSF proteins and a poor virological control possibly indicates compartmentalization of the virus in CSF and, consequently, plasma-independent intrathecal viral replication.     

NT-proBNP for risk stratification of pulmonary embolism

IntroductionPulmonary embolism (PE) is an entity with high mortality and morbidity, in which risk stratification for adverse events is essential. N-terminal brain natriuretic peptide (NT-proBNP), a right ventricular dysfunction marker, may be useful in assessing the short-term prognosis of patients with PE.AimsTo characterize a sample of patients hospitalized with PE according to NT-proBNP level at hospital admission and to assess the impact of this biomarker on short-term evolution.MethodsWe performed a retrospective analysis of consecutive patients admitted with PE over a period of 3.5 years. Based on the median NT-proBNP at hospital admission, patients were divided into two groups (Group 1: NT-proBNP < median and Group 2: NT-proBNP ≥ median). The two groups were compared in terms of demographic characteristics, personal history, clinical presentation, laboratory, electrocardiographic and echocardiographic data, drug therapy, in-hospital course (catecholamine support, invasive ventilation and in-hospital death and the combined endpoint of these events) and 30-day all-cause mortality. A receiver operating characteristic (ROC) curve was constructed to determine the discriminatory power and cut-off value of NT-proBNP for 30-day all-cause mortality.ResultsNinety-one patients, mean age 69 ± 16.4 years (51.6% aged ≥75 years), 53.8% male, were analyzed. Of the total sample, 41.8% had no etiological or predisposing factors for PE and most (84.6%) were stratified as intermediate-risk PE. Median NT-proBNP was 2440 pg/ml. Patients in Group 2 were significantly older (74.8 ± 13.2 vs. 62.8 ± 17.2 years, p = 0.003) and more had a history of heart failure (35.5% vs. 3.3%, p = 0.002) and chronic kidney disease (32.3% vs. 6.7%, p = 0.012). They had more tachypnea on initial clinical evaluation (74.2% vs. 44.8, p = 0.02), less chest pain (16.1% vs. 46.7%, p = 0.01) and higher creatininemia (1.7 ± 0.9 vs. 1.1 ± 0.5 mg/dl, p = 0.004). Group 2 also more frequently had right chamber dilatation (85.7% vs. 56.7%, p = 0.015) and lower left ventricular ejection fraction (56.4 ± 17.6% vs. 66.2 ± 13.5%, p = 0.036) on echocardiography. There were no significant differences in drug therapy between the two groups. Regarding the studied endpoints, Group 2 patients needed more catecholamine support (25.8% vs. 6.7%, p = 0.044), had higher in-hospital mortality (16.1% vs. 0.0%, p = 0.022) and more frequently had the combined endpoint (32.3% vs. 10.0%, p = 0.034). All-cause mortality at 30 days was seen only in Group 2 patients (24.1% vs. 0.0%, p = 0.034). By ROC curve analysis, NT-proBNP had excellent discriminatory power for this event, with an area under the curve of 0.848. The best NT-proBNP cut-off value was 4740 pg/ml.ConclusionElevated NT-proBNP levels identified PE patients with worse short-term prognosis, and showed excellent power to predict 30-day all-cause mortality. The results of this study may have important clinical implications. The inclusion of NT-proBNP measurement in the initial evaluation of patients with PE can add valuable prognostic information.     

Acute pulmonary and splenic response in an in vivo model of whole-body low-dose X-radiation exposure

Abstract

Purpose: Diagnostic radiation is an important part of patient care in the Intensive Care Unit; however, there is little data on the acute effects of exposure to these doses. We investigated pulmonary and splenic response 30?minutes, 4?hours or 24?hours after exposure to 2?mGy, 20?mGy, 200?mGy or 4?Gy whole-body X-radiation in a Sprague Dawley rat model.

Materials and methods: Lung injury was assessed via respiratory mechanics, pulmonary edema, cellular, and proteinaceous fluid infiltrate and protein expression of oxidative stress markers. The radiation effect on the spleen was determined via proliferation, apoptosis and protein expression of oxidative stress markers.

Results: All measurements of the lung did not differ from sham animals except for an increase in catalase after high dose exposure. Stimulated splenocyte proliferation increased after sham and low dose exposure, did not change after 200?mGy exposure and was significantly lower after 4?Gy exposure. The number of apoptotic cells increased 4?hours after 4?Gy exposure. There were fewer apoptotic cells after low dose exposure compared to sham. Both catalase and MnSOD were increased after 4?Gy exposure.

Conclusion: There was no measured effect on pulmonary function while there was an impact to the spleen after low and high dose exposure.     

Searching for species in haloarchaea

Prokaryotic (bacterial and archaeal) species definitions and the biological concepts that underpin them entail clustering (cohesion) among individuals, in terms of genome content and gene sequence similarity. Homologous recombination can maintain gene sequence similarity within, while permitting divergence between, clusters and is thus the basis for recent efforts to apply the Biological Species Concept in prokaryote systematics and ecology. In this study, we examine isolates of the haloarchaeal genus Halorubrum from two adjacent ponds of different salinities at a Spanish saltern and a natural saline lake in Algeria by using multilocus sequence analysis. We show that, although clusters can be defined by concatenation of multiple marker sequences, barriers to exchange between them are leaky. We suggest that no nonarbitrary way to circumscribe "species" is likely to emerge for this group, or by extension, to apply generally across prokaryotes. Arbitrary criteria might have limited practical use, but still must be agreed upon by the community.     

Reduced input from foot sole skin through cooling differentially modulates the short latency and medium latency vestibular reflex responses to galvanic vestibular stimulation

Sensory afferent information from the skin of the foot sole and information from the vestibular system converge within the central nervous system; however, their mode of interaction remains unknown. The purpose of this study was to investigate the effect of reduced cutaneous foot sole information on the ability of the vestibular system to evoke short latency (SL) and medium latency (ML) lower limb muscle reflex responses. Galvanic vestibular stimulation (GVS; bipolar; binaural; 25 ms; 2 mA square-wave pulse) was applied to standing human subjects (four women, eight men, average age 21.1 ± 3.0 years) both before and after cooling the foot soles in 1°C ice water (15 min initially, followed by 5 min between blocks of 200 GVS pulses). Changes in soleus reflex amplitude were examined. Following ice water immersion, there was a 35.16% increase in the size of the ML response in the soleus muscle when expressed as a percentage of pre-stimulus electromyographic (EMG) activity (control 26.48 ± 4.91%; ice 36.16 ± 6.52%) with no change in size of the SL response (control 7.42 ± 1.12%; ice 8.72 ± 1.10%). These results support the previously proposed dissociation of the SL and ML responses with respect to their circuitry and functions. The results also suggest a greater role for cutaneous-vestibular interaction in the modulation of the ML than the SL response and at a location prior to the motoneuron pool.