Binary tree-structured vector quantization approach to clustering and visualizing microarray data

MOTIVATION

With the increasing number of gene expression databases, the need for more powerful analysis and visualization tools is growing. Many techniques have successfully been applied to unravel latent similarities among genes and/or experiments. Most of the current systems for microarray data analysis use statistical methods, hierarchical clustering, self-organizing maps, support vector machines, or k-means clustering to organize genes or experiments into 'meaningful' groups. Without prior explicit bias almost all of these clustering methods applied to gene expression data not only produce different results, but may also produce clusters with little or no biological relevance. Of these methods, agglomerative hierarchical clustering has been the most widely applied, although many limitations have been identified.

RESULTS

Starting with a systematic comparison of the underlying theories behind clustering approaches, we have devised a technique that combines tree-structured vector quantization and partitive k-means clustering (BTSVQ). This hybrid technique has revealed clinically relevant clusters in three large publicly available data sets. In contrast to existing systems, our approach is less sensitive to data preprocessing and data normalization. In addition, the clustering results produced by the technique have strong similarities to those of self-organizing maps (SOMs). We discuss the advantages and the mathematical reasoning behind our approach.

A hybrid achromatic metalens

Metalenses, ultra-thin optical elements that focus light using subwavelength structures, have been the subject of a number of recent investigations. Compared to their refractive counterparts, metalenses offer reduced size and weight, and new functionality such as polarization control. However, metalenses that correct chromatic aberration also suffer from markedly reduced focusing efficiency. Here we introduce a Hybrid Achromatic Metalens (HAML) that overcomes this trade-off and offers improved focusing efficiency over a broad wavelength range from 1000–1800 nm. HAMLs can be designed by combining recursive ray-tracing and simulated phase libraries rather than computationally intensive global search algorithms. Moreover, HAMLs can be fabricated in low-refractive index materials using multi-photon lithography for customization or using molding for mass production. HAMLs demonstrated diffraction limited performance for numerical apertures of 0.27, 0.11, and 0.06, with average focusing efficiencies greater than 60% and maximum efficiencies up to 80%. A more complex design, the air-spaced HAML, introduces a gap between elements to enable even larger diameters and numerical apertures.

Metalenses that correct chromatic aberration also suffer from reduced focusing efficiency. Here, the authors introduce a Hybrid Achromatic Metalens which merges a metalens and phase plate to offer improved focusing efficiency over a broad wavelength range and diffraction limited imaging performance.

Eosinophilic annular erythema is a peculiar subtype in the spectrum of Wells syndrome: a multicentre long-term follow-up study

BACKGROUND/OBJECTIVE

Eosinophilic annular erythema (EAE) was proposed to describe annular skin lesions associated with tissue eosinophilia, however, its relation to Well's syndrome (WS) remains a source of controversy. We studied a series of patients to increase awareness of this entity and to clarify its relation to WS.

METHODS

A multicentre study in which the clinical records, histological findings, laboratory results, therapeutic responses and follow-up of 10 patients were demonstrated.

RESULTS

The study included seven women and three men with age ranging from 31 to 54 years. The duration of the disease ranged from 3 to 28 months. All patients showed involvement of trunk and extremities. Early lesions were manifested as erythematous plaques, which progressed to well-developed figurate lesions and ended as large annular lesions with pigmented centre and elevated border. Flame figures were only observed in well-developed and long-standing lesions. Blood eosinophilia was found in all patients with different grades. Associated disorders included chronic gastritis, diabetes mellitus, chronic hepatitis-C virus infection and chronic kidney disease. The disease showed chronic course with high relapse rate and resistance to various therapeutic modalities including systemic steroid alone and in combination with hydroxychloroquine and cyclosporine.

CONCLUSION

We believe that EAE is a peculiar clinical variant in the spectrum of WS, which is characterized by a chronic course, resistance to treatment and high relapse rate. The diagnosis and evaluation of this condition need a close monitoring with repeated clinical, histological and laboratory assessment.

Organic solute transporter-β (SLC51B) deficiency in two brothers with congenital diarrhea and features of cholestasis

Primary bile acid malabsorption is associated with congenital diarrhea, steatorrhea, and a block in the intestinal return of bile acids in the enterohepatic circulation. Mutations in the ileal apical sodium-dependent bile acid transporter (ASBT; SLC10A2) can cause primary bile acid malabsorption but do not appear to account for most familial cases. Another major transporter involved in the intestinal reclamation of bile acids is the heteromeric organic solute transporter alpha-beta (OSTα-OSTβ; SLC51A-SLC51B), which exports bile acid across the basolateral membrane. Here we report the first patients with OSTβ deficiency, clinically characterized by chronic diarrhea, severe fat soluble vitamin deficiency, and features of cholestatic liver disease including elevated serum gamma-glutamyltransferase activity. Whole exome sequencing revealed a homozygous single nucleotide deletion in codon 27 of SLC51B, resulting in a frameshift and premature termination at codon 50. Functional studies in transfected cells showed that the SLC51B mutation resulted in markedly reduced taurocholic acid uptake activity and reduced expression of the OSTα partner protein.

CONCLUSION

The findings identify OSTβ deficiency as a cause of congenital chronic diarrhea with features of cholestatic liver disease. These studies underscore OSTα-OSTβ's key role in the enterohepatic circulation of bile acids in humans. (Hepatology 2017).

Calprotectin in cystic fibrosis

BACKGROUND

There is increasing evidence that intestinal inflammation plays a major role in gastrointestinal symptoms in cystic fibrosis (CF). Fecal calprotectin is a marker that is elevated in several gastrointestinal inflammatory diseases, but little is known about its value in CF. We aimed to look for associations of elevated fecal calprotectin among CF patients and whether its level correlates with the clinical manifestations of CF.

METHODS

A single stool specimen was collected from 62 patients with CF. Fecal calprotectin was measured using the commercially available ELISA kits (PhiCal™ test). Clinical data were collected from patients' records and CF registry.

RESULTS

There were no significant differences between CF patients with normal and abnormal fecal calprotectin levels. However, patients who were not receiving inhaled antibiotics had higher fecal calprotectin levels than those who were.

CONCLUSION

Elevated fecal calprotectin may not accurately predict intestinal inflammation in CF. However, the fact that it was elevated in both pancreatic sufficient and insufficient groups supports the concept of "cystic fibrosis enteropathy" regardless of the pancreatic status.

Subjective global nutritional assessment in critically ill children

BACKGROUND

Underweight children admitted to the pediatric intensive care unit (PICU) have a higher risk of mortality than normal-weight children. The authors hypothesized that subjective global nutrition assessment (SGNA) could identify malnutrition in the PICU and predict nutrition-associated morbidities.

METHODS

The authors prospectively evaluated the nutrition status of 150 children (aged 31 days to 5 years) admitted to the PICU with the use of SGNA and commonly used objective anthropometric and laboratory measurements. Each child was administered the SGNA by a dietitian while anthropometric measurements were performed by an independent assessor. To test interrater reproducibility, 76 children had SGNA performed by another dietitian. Occurrence of nutrition-associated complications was documented for 30 days after admission.

RESULTS

SGNA ratings of well nourished, moderately malnourished, or severely malnourished demonstrated moderate to strong correlation with several standard anthropometric measurements (P < .05). The laboratory markers did not demonstrate any correlation with SGNA. Interrater agreement showed moderate reliability (κ = 0.671). Length of stay, pediatric logistic organ dysfunction, and Pediatric Risk of Mortality III were not significantly different across the groups and did not correlate with SGNA.

Reconstructive surgery of the pelvis after surgery for rectal cancer

The role of the reconstructive surgeon has increased with an increasingly aggressive surgical approach to locally advanced rectal carcinoma. Multiple options exist for pelvic floor reconstruction. Muscle and myocutaneous flaps for pelvic-floor reconstruction provide well vascularized tissues which may also serve as a biologic spacer. Flaps help to prevent post-radiation fistulae, small bowel obstruction, and pelvic sidewall adherence; flaps also may serve as a barrier to radiation injury. Often a more stable perineal wound closure is achieved. In cases that involve vaginal resection, flaps make neo-vaginal reconstruction possible. Pre-operative consultation with the reconstructive surgeon allows planning of complex, multi-disciplinary procedures, and facilitates patient understanding of the proposed procedure.

Induction of heme oxygenase-1 protects mouse liver from apoptotic ischemia/reperfusion injury

Ischemia/reperfusion (I/R) injury is the main cause of primary graft dysfunction of liver allografts. Cobalt-protoporphyrin (CoPP)-dependent induction of heme oxygenase (HO)-1 has been shown to protect the liver from I/R injury. This study analyzes the apoptotic mechanisms of HO-1-mediated cytoprotection in mouse liver exposed to I/R injury. HO-1 induction was achieved by the administration of CoPP (1.5 mg/kg body weight i.p.). Mice were studied in in vivo model of hepatic segmental (70 %) ischemia for 60 min and reperfusion injury. Mice were randomly allocated to four main experimental groups (n = 10 each): (1) A control group undergoing sham operation. (2) Similar to group 1 but with the administration of CoPP 72 h before the operation. (3) Mice undergoing in vivo hepatic I/R. (4) Similar to group 3 but with the administration of CoPP 72 h before ischemia induction. When compared with the I/R mice group, in the I/R+CoPP mice group, the increased hepatic expression of HO-1 was associated with a significant reduction in liver enzyme levels, fewer apoptotic hepatocytes cells were identified by morphological criteria and by immunohistochemistry for caspase-3, there was a decreased mean number of proliferating cells (positively stained for Ki67), and a reduced hepatic expression of: C/EBP homologous protein (an index of endoplasmic reticulum stress), the NF-κB's regulated genes (CIAP2, MCP-1 and IL-6), and increased hepatic expression of IκBa (the inhibitory protein of NF-κB). HO-1 over-expression plays a pivotal role in reducing the hepatic apoptotic IR injury. HO-1 may serve as a potential target for therapeutic intervention in hepatic I/R injury during liver transplantation.

Role of nutrition in pediatric chronic liver disease

The liver plays a central role in energy and nutrient metabolism. Malnutrition is highly prevalent among patients with chronic liver disease and leads to increased morbidity and mortality rates. This review addresses the causes of malnutrition, methods used to assess nutrition status, and appropriate treatment strategies in pediatric patients with chronic liver disease.

Spectrophotometric determination of acyclovir in some pharmaceutical formulations

A simple and reliable spectrophotometric method has been developed for the determination of acyclovir in pharmaceutical formulations. The method is based on its oxidative coupling reaction with 3-methylbenzothiazolin-2-one hydrazone (MBTH) in the presence of FeCl3 as an oxidant to produce deep-green colored species measurable at 616 nm. The absorbance-concentration plot is linear over the range 20-200 microg ml(-1) with minimum detectability of 1.06 microg ml(-1) (4.71 x 10(-6) M). The molar absorptivity was 9.41 x 10(2) l mol(-1) cm(-1) with correlation coefficient (n = 7) of 0.9998. The different experimental parameters affecting the development and stability of the color were studied carefully and optimized. The proposed method was applied successfully to the determination of acyclovir in its dosage forms. The percentage recoveries +/-SD (n = 9) were 98.63 +/- 0.34, 99.61 +/- 0.58, 99.35 +/- 0.58 and 99.72 +/- 0.86 for tablets, ophthalmic ointment and cream, respectively. A proposal of the reaction pathway was presented.

Ultrasonic preparation and obturation of root-end cavities

This study evaluated the preparation of root-end cavities using an ultrasonically activated file, and the obturation of such cavities. In the first part, the root canals of 40 extracted teeth were prepared to size 40 and irrigated with NaOCl and EDTA. The root ends were resected and the teeth inoculated with Enterococcus faecalis, incubated for 10 days and divided into four groups: control; saline; irrigation; hand instrumentation performed via a retrograde approach up to size 50 using saline irrigant; ultrasonic instrumentation with prebent size 40 K-flex file inserted into a Piezon Master using saline irrigant. The teeth were fixed, sectioned longitudinally and viewed under scanning electron microscopy. Bacterial and smear layer scores were obtained at 1, 3, and 5 mm from the resected end. The bacterial scores for control and saline groups were similar; the scores for each instrumentation group were significantly lower than the control group (P<0.001). In addition, there were significantly fewer bacteria in the ultrasonic group compared with the hand instrument group (P<0.001). The smear layer scores for control and saline groups were similar, and significantly lower than in either instrumentation group (P<0.001). In the second part, root-end cavities were ultrasonically prepared in 20 extracted teeth. Ten cavities were filled with amalgam, and 10 with thermoplasticized gutta-percha and Grossman's sealer. After 24-h storage, the root ends were immersed in dye for 48 h. Cross-sectional slices of the obturated part of the root were evaluated using both light and confocal microscopy for dye leakage along the interface of filling material and dentine. There were no statistical differences between the leakage of amalgam and gutta-percha root-end fillings, nor between the two methods of microscopy.

Tricho-hepato-enteric syndrome: a case of hemochromatosis with intractable diarrhea, dysmorphic features, and hair abnormality

We report on a female infant with congenital iron storage disease, facial dysmorphism, intractable diarrhea, and hair abnormalities. The intractable diarrhea failed to resolve despite total parenteral nutrition and complete bowel rest for more than 3 weeks. The patient also had elevated liver enzymes and failure to thrive. Histopathologic examination of the liver revealed marked iron deposits in hepatocytes with portal edema, fibrosis, and septal formation. No metabolic abnormalities could be detected. She died at the age of 10 months. We suggest that this case could have a specific iron storage syndrome that is similar to the two sibs reported by Stankler et al. [1982; Arch Dis Child 57:212-216] and Verloes et al. [1997; Am J Med Genet 68:391-395]. The condition was called the tricho-hepato-enteric (THE) syndrome.

Voltammetric study of danazol and its determination in capsules and spiked biological fluids

The voltammetric behaviour of danazol DZ (antigonadotropin) was studied using cyclic voltammetry, direct current, differential pulse polarography (DPP) and alternating current polarography. Danazol exhibited irreversible cathodic waves over the pH range of 1-5 in Britton Robinson buffers. At pH 1 (the analytical pH), a well-defined wave with E1/2 of -1.04 V versus Ag/AgCl reference electrode was obtained. The diffusion current constant (Id) was 4.8+/-0.14 microA.L.m mole(-1) and the current-concentration plot was rectilinear over the range from 5 x 10(-6) to 1 x 10(-4) M with correlation coefficient (n = 11) of 0.995. The calculated detection limit was 1 x 10(-6) M using the DPP mode. The wave was characterized as being irreversible, diffusion-controlled although adsorption phenomenon played a limited role in the electrode process. The proposed method was applied to commercial capsules and the average percentage recovery was in agreement with that obtained by the official USP method. The method was extended to the in vitro determination of DZ in spiked human urine and plasma samples, the percentage recoveries were 96+/-4 and 97+/-5, respectively. A proposal of the electrode reaction was postulated.

RIPK1 mutations causing infantile-onset IBD with inflammatory and fistulizing features

PURPOSE

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is an important regulator of necroptosis and inflammatory responses. We present the clinical features, genetic analysis and immune work-up of two patients with infantile-onset inflammatory bowel disease (IBD) resulting from RIPK1 mutations.

METHODS

Whole exome and Sanger sequencing was performed in two IBD patients. Mass cytometry time of flight (CyTOF) was conducted for in-depth immunophenotyping on one of the patient's peripheral blood mononuclear cells, and compared to control subjects and patients with Crohn's disease.

RESULTS

The patients presented with severe colitis and perianal fistulas in the first months of life, without severe/atypical infections. Genetic studies identified pathogenic genetic variants in RIPK1 (Patient 1, A c.1934C>T missense mutation in Exon 11; Patient 2, c.580G>A missense mutation residing in Exon 4). Protein modeling demonstrated that the mutation in Patient 1 displaces a water molecule, potentially disrupting the local environment, and the mutation in Patient 2 may lead to disruption of the packing and conformation of the kinase domain. Immunofluorescence RIPK1 staining in rectal biopsies demonstrated no expression for Patient 1 and minimal expression for Patient 2, compared to controls and patients with active Crohn's disease. Using CyTOF unbiased clustering analysis, we identified peripheral immune dysregulation in one of these patients, characterized by an increase in IFNγ CD8+ T cells along with a decrease in monocytes, dendritic cells and B cells. Moreover, RIPK1-deficient patient's immune cells exhibited decreased IL-6 production in response to lipopolysaccharide (LPS) across multiple cell types including T cells, B cells and innate immune cells.

CONCLUSIONS

Mutations in RIPK1 should be considered in very young patients presenting with colitis and perianal fistulas. Given RIPK1's role in inflammasome activation, but also in epithelial cells, it is unclear whether IL1 blockade or allogeneic hematopoietic stem cell transplantation can suppress or cure the hyper-inflammatory response in these patients. Additional studies in humans are required to better define the role of RIPK1 in regulating intestinal immune responses, and how treatment can be optimized for patients with RIPK1 deficiency.

Homozygous variant in MADD, encoding a Rab guanine nucleotide exchange factor, results in pleiotropic effects and a multisystemic disorder

Rab proteins coordinate inter-organellar vesicle-mediated transport, facilitating intracellular communication, protein recycling, and signaling processes. Dysfunction of Rab proteins or their direct interactors leads to a wide range of diseases with diverse manifestations. We describe seven individuals from four consanguineous Arab Muslim families with an infantile-lethal syndrome, including failure to thrive (FTT), chronic diarrhea, neonatal respiratory distress, variable pituitary dysfunction, and distal arthrogryposis. Exome sequencing analysis in the independent families, followed by an internal gene-matching process using a local exome database, identified a homozygous splice-site variant in MADD (c.2816 + 1 G > A) on a common haplotype. The variant segregated with the disease in all available family members. Determination of cDNA sequence verified single exon skipping, resulting in an out-of-frame deletion. MADD encodes a Rab guanine nucleotide exchange factor (GEF), which activates RAB3 and RAB27A/27B and is thus a crucial regulator of neuromuscular junctions and endocrine secretory granule release. Moreover, MADD protects cells from caspase-mediated TNF-α-induced apoptosis. The combined roles of MADD and its downstream effectors correlate with the phenotypic spectrum of disease, and call for additional studies to confirm the pathogenic mechanism and to investigate possible therapeutic avenues through modulation of TNF-α signaling.

Application of difference spectroscopy to the determination of some pharmaceutically important nitro compounds

A simple and selective spectrophotometric method for the determination of some pharmaceutically important nitro compounds has been developed. The suggested method depends upon the spectral changes induced by reduction using either Zn/HCl or Zn/NH4Cl. The different experimental parameters were studied and incorporated into the procedure. The mean percentage recovery ranged from 99 to 101. The proposed method was applied to the determination of the studied compounds in dosage forms, and the results obtained were compared favourably with those given with the compendial ones.

Severe persistent unremitting dermatitis, chronic diarrhea and hypoalbuminemia in a child; Hartnup disease in setting of celiac disease

Background

Celiac disease (CD) is a complex autoimmune disorder that can lead to an inflammatory small intestinal villous atrophy and malabsorption.

Hartnup disease is an autosomal recessive disorder caused by increased urinary excretion of neutral amino acids. Co-occurrence of Hartnup disease and CD is extremely rare with only a single case reported.

Case presentation

We report a 3-year girl with chronic diarrhea, Hypoalbuminemia and exfoliative erythema. She was diagnosed with celiac disease, which did not improve on gluten free diet. Hartnup disease was suspected and was confirmed by neutral aminoaciduria. Niacin was started and followed by dramatic improvement.

Conclusion

Presence of Celiac and Hartnup disease in single individual is very rare. Complete nutritional assessment of refractory celiac patient can reveal underlying nutritional deficiency.

The effect of postplacental insertion of the spiked and the standard Lippes loop on uterine involution

The spiked Lippes loop was inserted in 53 women and the standard loop in 55 women immediately following the delivery of the placenta after normal vaginal delivery. A group of 50 recently delivered women with no IUD was studied as a control. The cases were followed up for 1 year. Ultrasonic scanning was performed during the 6th week after insertion for 47 cases with the spiked loop and 43 cases with the standard loop. All loops were correctly positioned within the uterine cavity except in two cases; one using the spiked and the other using the standard loop. The loops were found displaced downwards and as there was excessive bleeding, the devices were removed. Regarding the effect of the IUD on uterine involution, it was found that the fundus to internal os length for the cases with IUDs was shorter than that among the controls, also this length among the standard loop users was significantly shorter than that of the controls (P less than 0.01). Postplacental IUD insertion did not delay uterine involution, on the contrary, it helped involution. Regarding the effect of lactation, the fundus to internal os length for the fully lactating women either using a loop or not, was found to be significantly shorter than that of the non-lactating cases (P less than 0.002).

Reduced pulmonary functions and respiratory muscle strength in Type 2 diabetes mellitus and its association with glycemic control

OBJECTIVE

Diabetes mellitus is one of the main devastating causes of mortality and morbidity due to its detrimental complications. We aimed to evaluate the pulmonary functions and respiratory muscle strength in relationship with glycemic control and gender in type 2 Diabetes Mellitus (T2DM).

MATERIALS AND METHODS

This cross-sectional study was performed at King Saud University and King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia from June 2107 to June 2019. We evaluated pulmonary functions, respiratory muscle strength, body composition and glycemic control in T2DM (n=110) and control group (n=119). Gender differences were also evaluated in T2DM.

RESULTS

Subjects with T2DM have significantly decreased forced vital capacity (FVC) (3.6±0.7 vs 3.3±0.9, p = 0.012), forced expiratory volume in first second (FEV1) (3.3±2.2 vs 2.7±0.6, p = 0.019), peak expiratory flow (PEF) (127.4±210.9 vs. 49.2±133.6, p = 0.003), FEF25-75 (3.6±1.3 vs. 3.1±1.1, p-value = 0.025), and maximum inspiratory pressure (MIP) (99.3±26.9 vs. 87.4±19.3, p=0.001). However, no significant difference between control and diabetes was found in maximum expiratory pressure (MEP) (132.5±34.9 vs 126.2±30.0, p = 0.202). Significant reduction in FVC (male=3.7±0.8 vs female = 3.0±0.7 p = 0.000), FEV1 (3.3±1.9 vs 2.6±0.5 p = 0.000), FEF25-75 (3.6 ± 1.3 vs 2.9 ± 1.0 with p-value = 0.000), MIP (96.9±23.1 vs 87.5±27.1 with p = 0.017), and MEP (134.0±32.2 vs. 120.1±33.5 with p = .011) were observed in females compared to males in T2DM subjects.

CONCLUSIONS

Decline in the pulmonary function and inspiratory muscle strength are associated with poor glycemic control in T2DM. Moreover, there are significant differences between male and female in lung parameters and inspiratory as well as expiratory muscles strength. The exact pathophysiological mechanism to explain this association requires further investigations.

Strategic response to COVID-19 in Ethiopia

COVID-19, the novel coronavirus, has posed a major threat to low- and middle-income countries (LMICs) due to inadequate health infrastructure and human resources. Ethiopia, a low-income country with the second largest population in Africa, has coordinated a strategic response, leveraging existing infrastructure and health systems and mobilizing public health professionals and specialist expert physicians for a multifaceted, unified government approach and adaptive response. Resource limitations, particularly in critical care, have still posed challenges, but the public health and clinical interventions thus far have prevented the catastrophic toll that many predicted. As the pandemic continues, Ethiopia expects to use a triple care model integrated at all levels, consisting of COVID-19 care, isolation care for suspected cases, and essential health services, and urges intensified non-pharmaceutical interventions alongside equitable global vaccine distribution as the ultimate answers to pandemic control. This paper draws on existing data, national planning and guidelines, and expertise from health leadership to describe this response in hopes of providing an example of how future large-scale health challenges might be faced in LMICs, using Ethiopia's successes and challenges in facing the pandemic.

Estimating treatment effect of tafamidis on hospitalisation in NYHA class III ATTR-CM patients in the presence of death using principal stratification

Background

Hospitalisation has been widely used as a measure of morbidity in clinical trials for chronic heart failure. As previously reported in the Transthyretin Amyloidosis Cardiomyopathy Clinical Trial (ATTR-ACT), the observed frequency of cardiovascular (CV)-related hospitalisations favoured tafamidis over placebo in all analyses except in the NYHA Class III baseline subgroup with a relative risk of 1.41 [95% CI: 1.05, 1.90]1. However, the evaluation of the causal effect of treatment on hospitalisation is complicated in the presence of death as death precludes further hospitalisation and thus limits the evaluation of hospitalisation rates between groups. This confounding effect of death is particularly relevant in NYHA Class III participants who had higher mortality rates compared to Class I or II participants.

Purpose

This aim of this study was to assess the impact of the confounding effect of death on CV-related hospitalisation.

Methods

The effect of tafamidis treatment on CV-related hospitalisations was defined and compared in the subset of participants from either treatment arm who were alive at the end of the study (ie, Month 30); however the subset of participants who survive on the tafamidis arm would be expected to have different characteristics from the subset of participants who survive on the control arm and thus these analyses do not estimate the causal effect.

To address this possible survivor bias, we additionally conducted a post hoc principal stratification analysis. Principal stratification is a statistical method to adjust for post treatment events, in this case mortality, by classifying participants according to their potential to survive under each treatment arm. Specifically, we sought to estimate the principal strata effect on CV-related hospitalisations in NYHA Class III participants who would survive irrespective of treatment assignment. Sensitivity analyses were performed to assess the model assumptions.

Results

The analysis within the subset of participants who survived at Month 30 demonstrated a relative risk of 1.1 (95% CI: 0.56, 2.16) between tafamidis and placebo. The principal stratification analyses of subjects who would survive to 30 months irrespective of treatment estimated a 0.75 (95% CI: 0.44, 1.23) relative risk between tafamidis and placebo, suggesting a 25% reduction in frequency of CV-related hospitalisations in the tafamidis arm.

Conclusion

The initial data reported in ATTR-ACT likely underestimated the true effect of tafamidis on CV-related hospitalisations due to the confounding effect of death. The analysis of treatment group among observed survivors estimated a smaller relative risk for NYHA Class III; however, this analysis does not fully address the possible survivor bias. The survivor average causal effect, which adjusts for the survival bias demonstrated a reduction in the frequency of CV-related hospitalisation in the tafamidis treated arm for NYHA Class III participants.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Pfizer

[Reliability of needle biopsy of solitary thyroid nodules in view of surgical indications]

To evaluate the accuracy of fine-needle biopsy in the management of the solitary thyroid nodules, 320 biopsies without aspiration were performed in 212 patients, iteratively in 91 cases. Among the 212 initial biopsies, 93 smears were found presumably benign (43.9%), 6 malignant (2.8%), 49 benign implying cytologic control (23.1%), 24 suspicious with decision to operate (11.3%), 40 inadequate (18.9%). On 67 surgical indications (malignant or suspicious cytology, or clinical data), 59 operations were performed. The 11 diagnosed cancers (5.2% of the patients; 18.6% of the operations) correspond to six malignant and five suspicious cytologies at the first or second biopsy. On 145 cases without decision to operate, 125 were clinically surveyed, with sometimes another biopsy (mean survey: 27.6 months; range: 6-80 months), and it was never necessary to modify the initial expectancy attitude. Our results, rather similar to those related by most of the previous publications, confirm that the fine-needle biopsy is a reliable and effective means for the etiologic diagnosis of thyroid nodules and the indications for operative intervention. It spares many patients from a useless operation and is worthy to take a leading place in exploring these nodules.

Fournier’s gangrene: outcome analysis of 62 consecutive cases

Objectives:

The objective of this article is to study the outcome of management of 62 consecutive cases of Fournier’s gangrene (FG).

Patients and methods:

We conducted an observational study of all cases of FG admitted to the Urology and General Surgery departments of Farwaniya Hospital, Kuwait, between 2004 and 2013. We recorded the laboratory and clinical findings on admission. Operative and postoperative data were also recorded.

Results:

Our study included 62 cases of FG. Patients were divided into two groups: Group A (survival) consisted of 55 cases and Group B (mortality) of seven cases. The mean duration of symptoms before admission was significantly longer in the mortality group (3.86 days versus 1.96 days in survival group) ( p < 0.05). The mean duration of symptoms until time of first debridement was also significantly longer in the mortality group (4.39 days versus 2.35 days in survival group) ( p < 0.05). There was also a statistically significant difference between the two groups regarding the percentage of the affected area in relation to total body surface area (4.6% in Group A versus 8% in Group B) ( p < 0.05). The Fournier Gangrene Severity Index score (FGSI) was significantly higher in Group B (10.26) in comparison to Group A (6) ( p < 0.01). The mean duration of hospital stay was significantly higher in the survival group (22.24 days versus 14.28 days) ( p < 0.01). Diabetes and renal failure were significantly higher in the mortality group (100% and 57.1% in Group B versus 54.5% and 9.1% in Group A, respectively) ( p < 0.05). The number of patients presenting with severe sepsis was higher in the mortality group (71.4% in Group B versus 12.7% in Group A) ( p < 0.05).

Conclusion:

We concluded that FG is a serious, potentially fatal disease. Higher mortality is related to severe sepsis on admission, renal failure, diabetes, extensive disease involving extra-genital areas and late presentation. A multidisciplinary approach in diagnosis and management of the disease can achieve good outcome with low mortality rate.