Mixed adenoneuroendocrine carcinoma of the gallbladder, histopathological features.

An unusual case of mixed adenoneuroendocrine carcinoma is described which posed a diagnostic challenge in view of neuroendocrine component mimicking signet ring cells of adenocarcinoma. Diagnostic criteria for these mixed tumors, their histogenesis and treatment modalities are highlighted.

Detection of M. tuberculosis in clinical samples of diversified nature by IS6110 based PCR.

Performance of the polymerase chain reaction technique based on IS6110 sequence was evaluated in clinical samples obtained from pulmonary and extrapulmonary cases of tuberculosis. One hundred and seventy two samples were processed for detection of M. tuberculosis by ZN stained smear examination, LJ medium culture, BACTEC radiometric culture and PCR tests amplifying 123bp region of IS6110 sequence. A significant difference was seen in the sensitivities of different tests, the figures being 83% for PCR test, 35.2% for smear examination, 47.16% for LJ culture and 53.45% for BACTEC culture (p < 0.05). However, no significant difference was found as far as specificity was concerned. PCR test sensitivity in. pulmonary and extrapulmonary clinical samples were 90.14% and 77.27% respectively and found to be significantly higher (p < 0.05) when compared with those of other tests. The mean detection time for M. tuberculosis was 24.03 days by LJ medium culture, 12.89 days by BACTEC culture and less than one day by PCR test. PCR based on IS6100 sequence is highly sensitive method for the early diagnosis of pulmonary and extrapulmonary tuberculosis.

Molecular characterization of mutation associated with rifampicin and isoniazid resistance in Mycobacterium tuberculosis isolates.

Nucleotide changes in catalase peroxidase (Kat G) gene and gene encoding the beta subunit of RNA polymerase (rpo B), responsible for isoniazid and rifampicin drug resistance were determined in the clinical isolates of Mycobacterium tuberculosis by PCR-RFLP, Line probe assay and DNA sequencing. PCR-RFLP test was performed by HapII cleavage of an amplified fragment of Kat G gene to detect the transversion 315AGC-->ACC(Ser-->Thr) which is associated with INH drug resistance. The Line probe assay kit was evaluated to detect the mutation in 81bp RMP resistance determining region of rpo B gene associated with RMP drug resistance. These results were validated by DNA sequencing and drug susceptibility test. Kat G S 315 T mutation was found in 74.19% strains of M. tuberculosis from Delhi. This mutation was not found in any of the susceptible strains tested. The line probe assay kit and DNA sequencing identified 18 isolates as RMP resistant with specific mutation, while one of the RMP resistant strain was identified as RMP susceptible, with a concordance of 94.73% with the phenotypic drug susceptibility result. Majority (8 of 19, 42.1%) of resistant isolates involved base changes at codon 531 of rpo B gene. Both PCR-RFLP and Line probe assay test can be used in many of the clinical microbiology laboratories for early detection of isoniazid and rifampicin drug resistance in clinical isolates of M. tuberculosis.

Median pancreatectomy: a report of three cases.

Conventional pancreatic resections may be unnecessary for tumors of the pancreas that are benign or of low malignant potential and can place the patient at increased risk of developing postoperative exocrine and endocrine complications. Median pancreatectomy is an option that has been investigated in the management of such tumors located in the body of the pancreas. We present our experience with three women who underwent this procedure successfully for neuroendocrine tumors (2) and cystadenoma (1).

Comparative study of PCR, smear examination and culture for diagnosis of cutaneous tuberculosis.

Diagnosis of tuberculosis (TB), especially cutaneous TB by conventional laboratory method is unreliable and time consuming. We assessed the utility of Polymerase Chain Reaction (PCR) test vis a vis other laboratory tests in 37 clinical samples of skin biopsy from equal number of patients with different variants of cutaneous TB. The PCR test amplifying 165bp region of 65kDa antigen coding gene specific for M. tuberculosis was performed on skin biopsy samples obtained from cases with a strong clinical evidence of cutaneous TB. The samples were also subjected to other laboratory tests e.g. smear examination, conventional (LJ based culture) and rapid BACTEC culture and histopathological examination for mycobacteria. Significant difference (p<0.05) was observed in the sensitivity of PCR test vis-a-vis other tests e.g. smear examination, LJ and BACTEC culture. PCR test showed a higher sensitivity than histopathological examination but the difference was not found to be statistically significant (p>0.05). PCR test showed the maximum positivity of 79.4% followed by histopathology (73.5%), BACTEC culture (47.5%), LJ media culture (29.4%) and smear examination (5.8%). The sensitivity and specificity of PCR test employing culture as the "gold standard" were 95.2% and 100%. The mean time taken for a positive result in different tests were less than 24 hours for smear examination, 1 day for PCR test, 23.42 days for BACTEC culture and 38.02 days for LJ culture. These results show that PCR amplification of 165bp region of 65kDa antigen coding gene of M. tuberculosis is a rapid and sensitive test for diagnosis of cutaneous TB using skin biopsy samples.

In-vitro study of mouse peritoneal macrophage response to virulent and avirulent strains of mycobacteria.

An immunological study of pathogenesis of tuberculosis was carried out in BALB-c mice in-vitro. Peritoneal macrophages obtained from BALB-c mice were challenged with virulent (H37Rv) and avirulent (H37Ra, BCG, M. phlei) strains of mycobacteria. Activated peritoneal macrophages showed enlargement, presence of intracellular bacteria and vacuolation. These significant changes in macrophage morphology were clearly evidenced in cells infected with virulent strains of Mycobacterium tuberculosis i.e. H37Rv while being absent in cells infected with avirulent H37Ra, BCG and M. phlei. Virulent mycobacteria (H37Rv) survive the phagocytic action of macrophages by residing inside the vacuoles. The capacity of virulent and avirulent strain to stimulate TNF-alpha production from peritoneal macrophage of BALB-c mice was also examined at different time interval i.e. 1,2,4,6 and 8th day by measuring cytolytic activity of culture supernatant against murine fibroblast cell line. The pattern of highest TNF release was in case of H37Rv and least with M. phlei as measured in culture supernatant after 1,2,4,6 and 8th day.

Vascular tethering of the megaoesophagus by the azygos arch masquerading as a malignancy.

We report the case of a 50-year-old male, a known case of achalasia cardia for 15 years, who after being successfully treated earlier by pneumatic dilatation, presented with recurrent dysphagia due to vascular tethering of the megaoesophagus by the azygos arch simulating a malignant oesophageal stricture. The patient underwent oesophagectomy because of our inability to rule out the possibility of a malignancy developing in the mid-portion of the long-standing megaoesophagus. We wish to highlight the existence of this new clinical entity and the diagnostic as well as therapeutic dilemmas posed by it.

Drug resistance in tuberculosis in Delhi: a 2 year profile (2001--2002).

234 isolates of Mycobacterium tuberculosis obtained from 1000 suspected cases of tuberculosis reporting at National Institute of Communicable Disease, Delhi for laboratory investigation between Jan 2001 to August 2002 were subjected to invitro drug sensitivity test against the first line drugs (Isoniazid, Streptomycin, Rifampicin, Ethambutol and Thiacetazone) by proportion method using Lowenstein Jensen (LJ) media. Out of 234 isolates of Mycobacterium tuberculosis, 142 were from cases of untreated tuberculosis, whereas only 92 isolates were from treated cases of tuberculosis. An initial drug resistance of 21.83% was seen against INH, 9.85% against Streptomycin, 15.49% against Rifampicin, 4.22% against ethambutol and 2.11% to thiacetazone. Multidrug resistance (MDR-i.e. Resistance to both INH and Rifampicin) was seen in 11.97% of isolates. 4(2.8%) isolates were found to be resistant to all drugs tested. A much higher level of acquired resistance was seen the figures being 61.95% for INH, 53.36% for rifampicin, 35.86% for streptomycin, 20.65% for ethambutol and 10.86% for thiacetazone. Avery high acquired MDR to the tune of 42.39% was seen. 24(26%) isolates were found to be resistant to all drugs tested. No significant difference were observed in the drug resistance pattern between pulmonary and extrapulmonary cases of tuberculosis in both initial and acquired drug resistance category.

Surgical management of obstructive gastroduodenal tuberculosis.

BACKGROUND: Gastroduodenal tuberculosis is a rare but potentially curable condition. The aim of the present study was to evaluate the clinical presentation, pre-operative status, management and outcome in patients with histologically proven diagnosis of gastroduodenal obstruction due to tuberculosis. METHODS: We retrospectively reviewed the records of 17 patients managed surgically for gastroduodenal obstruction due to tuberculosis. RESULTS: The site of obstruction was the pyloroduodenal canal in 53% of patients, second part of the duodenum in 24%, third part of the duodenum in 12% and duodenjojejunal flexure in 12%. The obstruction was caused by fibrotic stricture formation in 59% of patients and extrinsic compression by a lymph nodal mass in 41%. Endoscopic biopsy was diagnostic in only 29% of the patients in whom it was performed. Overall, a pre-operative diagnosis of gastroduodenal tuberculosis was suspected in only 35% of patients. All the patients underwent surgical drainage procedures and the diagnosis was confirmed by histopathological examination of biopsies taken at the time of laparotomy. CONCLUSIONS: In view of its rarity and non-specific findings on clinical, radiological and endoscopic evaluation, tuberculosis as a cause of gastroduodenal obstruction is seldom diagnosed pre-operatively. Hence, a high index of suspicion is required in young patients residing in endemic areas. Surgical intervention helps not only in relieving obstruction but also in confirming the diagnosis.