Two sample comparisons including zero-inflated continuous data: A parametric approach with applications to microarray experiment

Micro-array experiments are important fields in molecular biology where zero values mixed with a continuous outcome are frequently encountered leading to a mixed distribution with a clump at zero. Comparison of two mixed populations, e.g. of a control and a treated group; of two groups with different types of cancer, to name a few, are often encountered in these contexts. Fairly skewed distribution of the continuous part coupled with small sample sizes are issues of main concern to be attended for the quality of inference in such situations while popularly used nonparametric methods rely on asymptotic distribution of the underlying test statistics which are valid only under large sample sizes. We address the aforementioned issues via a newly proposed exact test for location-scale family distributions and Generalized pivot quantity (GPQ) based parametric test procedures for non-location-scale distributions. Simulation based assessment showed their superior performance with respect to size and power in comparison to the popular two-part tests (Wilcoxon rank sum, t-test, Kolmogrov-Smirnov, Ansari-Bradley and Sigel-Tukey) more prominently for small sample sizes.

Atypical Lymphocytes and Cellular Cannibalism: A Phenomenon, First of its Kind to be Discovered in Chronic Periapical Lesions

INTRODUCTION

Lymphocytes are often termed to be isomorphic, having a monotonous light microscopic appearance. Morphological aspects of lymphocytes in tissue sections thereby are not routinely taken notice of as their morphology seems to vary only in case of lymphoid malignancies, hematological malignancies apart from certain viral infections. Atypical lymphocytes are the lymphocytes with unusual shape, size or overall structure. These are more commonly known as reactive lymphocytes. The unusual histomorphological feature of these cells include larger size than normal lymphocytes; in some cells the size exceeds even 30 microns. The large size is the result of antigenic stimulation of the cell. Alongwith these, the other rare feature which is recently coming under light is "Cellular Cannibalism" which is defined as a large cell enclosing a slightly smaller one within its cytoplasm. Previously, this feature was noted only in cases of malignant tumors.

AIM

The objectives of this study were to determine the proportion of atypical lymphocytes in chronic periapical granulomas and cysts; to determine the proportionate cellular cannibalism in these periapical lesions.

MATERIALS AND METHODS

This was a descriptive, observational study conducted in the Department of Oral Medicine and Radiology and Oral Pathology and Microbiology. Haematoxylin and eosin stained 30 slides of chronic periapical granulomas and 20 slides of cysts reported in the year 2014-15 and the clinical proformas of the patients were retrieved from the files of the Department of Oral Medicine and Radiology and Oral Pathology and Microbiology. These slides were evaluated by 3 experts from the specialization of Oral Pathology and Microbiology to determine the presence of atypical lymphocytes and cellular cannibalism under high power magnification (400X).

RESULTS

Out of the 30 slides of chronic periapical granulomas, about 12 slides (40%) revealed presence of atypical lymphocytes. In case of slides of chronic periapical cysts, however, only 4 out of the 20 slides (20%) examined histopathologically showed presence of atypical lymphocytes. An interesting feature of cellular cannibalism was noted in tissues with atypical cells. Cannibalistic cells were present in 12 out of the 30 slides of chronic periapical granulomas (40%). None of the cysts, however, revealed cannibalistic cells (0%).

CONCLUSION

In the present study, we have quoted our observations on the unique cellular composition that was seen in histopathological sections of chronic periapical lesions. As also it was noted that those cases in which atypical cells & cellular cannibalism was evident the lesion clinically showed size more than 5cm. The question arises that whether presence of atypical cells from the tissue sections in these lesions denotes an aggressive clinical behavior and should be given a due consideration in deciding the treatment protocols for such cases to provide an optimum patient care.

Comparative Evaluation of Clinical, Hematological and Systemic Inflammatory Markers in Smokers and Non-Smokers with Chronic Periodontitis

Context:

Systemic conditions, especially chronic infections, have a direct impact on the general health and well-being of an individual. Similarly, the long-standing inflammatory changes seen during periodontitis have been associated with the altered diabetic control, preterm, low birth weight infants, and cardiovascular disease. Being a low-grade infection, the signs may not be as severe as seen in other systemic conditions, but they definitely cannot be ignored.

Aims:

The present study was designed to compare clinical, hematological, and systemic inflammatory markers in patients with chronic periodontitis.

Subjects and Methods:

A total of 90 chronic periodontitis patients were selected for the present study from the outpatient department of the Department of Periodontology, and the various clinical and hematological parameters were then assessed.

Statistical Analysis Used:

Z-test was used to compare the probing depth, clinical attachment loss, hematological parameter, and interleukin-6 values between Group A and Group B. Mann–Whitney U-test was used to compare gingival index, plaque index, and bleeding on probing between Group A and Group B.

Results:

The results of the study were based on the comparison of the clinical, hematological, and systemic inflammatory markers in smokers and nonsmokers with chronic periodontitis and came out to be statistically highly significant.

Conclusions:

With the resurgence of emphasis on significance of oral diseases related to systemic health, the medical professionals also need to familiarize themselves with the oral cavity and the oral-systemic inter-relationships to treat or reduce the morbidity of the underlying medical condition. Furthermore, the oral health care professionals must reach out to the medical community and the general public to improve patient care through education and communication about the oral health-systemic health link.

Gingival depigmentation: A split mouth comparative study between scalpel and cryosurgery

Gingival hyperpigmentation is a major esthetic concern for many people. Although it is not a medical problem, many people complain of dark gums as unesthetic. Gingival depigmentation is a periodontal plastic surgical procedure, whereby the hyperpigmentation is removed or reduced by various techniques. For depigmentation of gingival, different treatment modalities have been reported, such as scalpel, cryosurgery, electrosurgery, lasers, etc., this article compares the management of three cases with scalpel and cryosurgery and also highlights the relevance of cryosurgery.

The source of organisms in the post-prostatectomy bacteriuria of patients with pre-operative sterile urine

Ninety patients undergoing prostatectomy for benign prostatic hyperplasia (BPH) with sterile urine pre-operatively were prospectively studied for post-prostatectomy bacteriuria; 26 of 90 patients (29%) developed bacteriuria (18 of 64 after transurethral resection (TUR) and 8 of 26 after open prostatectomy), of whom 15 had pre-operative indwelling urethral catheters. The correlation of bacteriuria with several factors was studied, namely the presence of a histological inflammatory reaction within the prostatic adenoma, prostatic culture, intra-operative outgoing irrigation fluid culture, intra-operative blood culture and post-operative external meatal swab culture. The only significant correlation was between bacteriuria and meatal cultures. It was concluded that post-prostatectomy bacteriuria is probably caused by post-operative ascending infection along urethral catheters. There was not enough evidence to ascribe bacteriuria to pre-existing septic foci within the adenoma. Intra-operative contamination and infection from distant foci were also unlikely causes.

Bilharzial and nonbilharzial bladder cancer in Asir: A comparative clinicopathological study

A total of 48 bladder cancer patients out of 96 consecutive genitourinary cancer cases were divided into bilharzial and nonbilharzial groups on a histological basis in order to investigate the impact of bilharziasis on tumor behavior. Despite being a bilharzial endemic area, only 10/48 (21%) of our patients had bilharzial cancer (BC) of whom 8 (80%) had squamous cell carcinoma (SCC) and 2 (20%) had adenocarcinoma. Out of 38 patients with nonbilharzial cancer (NBC), 35 (92%) had transitional cell carcinoma (TCC), and 3 (8%) had SCC. BC in males presented at a younger age than NBC (P<0.05). All ten patients with BC presented with deeply invasive (T3 and T4) tumors as compared to 22/38 (58%) with NBC (P<0.05). Comparison of clinical and laboratory features in both groups in both groups did not reveal any significant difference. We conclude that in the Asir region, TCC is the most common bladder cancer. However, with bilharziasis, bladder cancer tends to be of the squamous type and presents at an earlier age and at an advanced stage.

Management of hydatid cysts of the urinary tract

Eleven patients with hydatid disease of the urinary tract have been seen in the last 5 years. Seven patients had cysts of the kidneys and 4 had large retrovesical hydatids. Seven of the 8 patients with renal hydatids presented with loin pain and mass. Three patients with renal communicating hydatids also presented with haematuria which was due to passing "grape skin" (hydatid membrane) in the urine. Two patients with retrovesical hydatids had bladder outflow obstruction and 2 had bilateral ureteric obstruction leading to uraemia. Eight of 11 patients had associated hydatids of other organs such as the liver (4 patients), peritoneal cavity (2) and lungs (1). Computed tomography was the most useful and specific investigation. In both renal and pelvic (retrovesical) hydatid cysts, endocystectomy with either partial excision or plication of the ectocyst is the standard treatment. In renal communicating hydatids the options are either nephrectomy (partial or total) or endocystectomy with closure of the communication. The use of cryocone and scolicidal agents is mandatory during surgery.

Is intravenous urography mandatory in the management of benign prostatic hyperplasia?

Fifty-four consecutive patients with uncomplicated benign prostatic hyperplasia (BPH) underwent intravenous urography (IVU) and ultrasonography (US) to observe the benefits of IVU over US. The parameters used were upper tract abnormalities detected on both modalities and the influence of radiological prostatic impression (RPI) on the route of surgery and its comparison to digitally estimated prostatic size (DEP). Both RPI and DEP were compared to the adenoma weight (AW). Correlation of RPI and DEP was excellent (87.5%) in grade III but poor in grades I and II. RPI and AW correlated well in grade III (100%) and was also significant in grades I and II, whereas DEP correlated well with AW in all grades. Both RPI and DEP could predict the route of prostatectomy accurately in grades I and III, whereas in grade II, RPI was marginally better in predicting the route. There was no upper tract abnormalities that were detected on IVU and missed by US. In conclusion, IVU did not add any additional information beyond that obtained by rectal examination and US to alter the surgical approach and hence the routine use of urography in uncomplicated BPH should be questioned in Saudi Arabia.

Specific investigations in chronic urinary bilharziasis

Seventy-two patients with histologically confirmed chronic urinary bilharziasis were studied for the reliability of some specific investigative tools in diagnosing this disease, namely urinalysis, serology, urography, and cystoscopy. Of the 72 patients 36 (50%) had hematuria and only 3 (4%) had ova of Schistosoma haematobium on urinalysis. Sixty-two patients (86%) had features of bilharziasis on intravenous urography (IVU). Of the remaining 10 patients with negative urography 6 underwent serology and all had positive results. Of the total patients 52 underwent serology and 49 had significant bilharzial antibody titer (94.2%). At cystoscopy all patients (100%) had features of bilharziasis. It is concluded that the most reliable diagnostic tools in chronic urinary bilharziasis are cystoscopy, serology, and to a lesser extent urography. Unlike early bilharziasis, chronic bilharziasis can be missed if total reliance is placed on urinalysis for screening a population at risk.

Hydatid disease of the urinary tract: evaluation of diagnostic methods

Eight patients with histologically proven hydatid disease of the urinary tract underwent eosinophil count, ultrasonography (US) and computed tomography (CT). The findings were compared with those in 8 age-matched controls with simple renal cysts. Eosinophilia was not significantly different in the 2 groups. Mixed echogenicity on US and multivesicular cyst with mixed density on CT were the diagnostic features of hydatid cysts. Using these factors, both US and CT could diagnose or exclude hydatid disease in a significant number of patients with renal cysts. However, CT was more sensitive (88 vs 50%) and accurate (94 vs 75%) than US in the diagnosis of urinary tract hydatid disease. Retrograde pyelography confirmed communicating renal hydatid cysts in 2 patients. A practical algorithm for the investigation of urinary tract hydatid disease is suggested.

Bilharzial vesicoureteric reflux and bladder neck stenosis: fact or fiction?

A group of 47 patients with histologically confirmed chronic urinary bilharziasis underwent micturating cystourethrography to look for vesicoureteric reflux (VUR) and bladder neck stenosis (BNS); 13 patients were found to have VUR of varying grades (8 unilateral and 5 bilateral). None had evidence of BNS. Urinary tract infection (UTI), loin pain, hydroureter and renal failure were compared in patients with and without VUR. Of the 13 patients with reflux, 3 had UTI, loin pain was present in 8, 11 had an ipsilateral hydroureter and 2 presented with renal failure. In the 34 patients without reflux, 8 had UTI, loin pain was present in 22, 30 had hydroureter and 3 presented with renal failure. It was concluded that the incidence of UTI, loin pain, hydroureter and renal deterioration associated with bilharzial VUR was not significantly different from that found in bilharzial patients without VUR. Thus the clinical significance and the need for surgical correction of isolated VUR in bilharziasis are questionable.