Biomedical subjects

P Hazarika

Publications and source records attributed to P Hazarika.

At least 19 recordsLinked to original sources

PubMed2006

Removal of iron from groundwater by ash: a systematic study of a traditional method.

A traditional method for removal of iron from ground water by using ash has been systematically investigated. Ashes from five different sources, viz., banana rind, banana pseudostem, banana leaf, rice husk and bamboo has been studied. The principle applied is enhanced precipitation of iron at high pH caused by ash. The study included laboratory analysis of some relevant chemical parameters of the ashes and the efficiency of the ashes in removing iron from prefabricated water with respect to quantity of ash and corresponding increase in pH of water. The ash of banana pseudostem has been found to be most suitable for removal of iron. A low-cost and easily made iron removal system for household use has been designed and tested in the laboratory. The ash of banana pseudostem has been found to remove iron to below 0.3ppm without increasing the pH above the acceptable limit. The optimum values of the different parameters for removal of iron are 200-300mgl(-1) ash, 1.0lh(-1) flow rate and 1h of contact time with ash for groundwater having [Fe] of about 2.20ppm. The amount of ash can be increased for groundwater having higher [Fe] and can be decreased gradually during continuous use of the system. Acceptability of the method has been examined based on chemical analysis of the treated water. Increase in the essential minerals such as Ca, K has been observed in the water after treatment. The designed iron removing system is expected to be suitable for household use.

Bambusa↗

PubMed2004

Surgical access to parapharyngeal space tumours--the Manipal experience.

A few series of parapharyngeal space tumours have been reported earlier but recently not many series have been published in English literature. It is rare for any medical center, let alone an individual surgeon, to develop sufficient experience in evaluating these tumours. We present our experience in the treatment of 41 cases of parapharyngeal tumours from January 1992 to December 2001. FNAC, ultrasound and CT scan of the presenting mass was done in most of the patients as the main pre-operative work-up. The strategic location and extension of the tumour may occasionally alter the surgical approach for tumour excision.

Adenoma↗

PubMed2001

Congenital cervical bronchogenic cyst.

A bronchogenic cyst is a rare developmental aberration that occurs in the paediatric age group. Over 50 cases of bronchogenic cysts have been reported in the literature. There is still a possibility of clinically misdiagnosing this condition as a more common congenital neck cyst like a branchial cyst. We report here the case of a 12-year-old female presenting with a neck swelling since birth who was diagnosed to have a bronchogenic cyst based on characteristic clinical and histopathological findings.

Bronchogenic Cyst↗

PubMed2001

Clear cell carcinoma of the larynx--a case report.

Clear cell carcinoma (CCC) of the larynx is extremely rare and to the best of our knowledge no such case has been reported in the paediatric age group. These tumours resemble the clear cell carcinoma of the major and minor salivary glands. We report such a lesion in a 15 years old boy presenting with hoarseness and an exophytic growth in the glottis. A frontolateral conservation laryngectomy with laryngoplasty was done and over 2 years follow-up has shown no evidence of loco-regional recurrence and he enjoys an acceptable voice.

Adenocarcinoma, Clear Cell↗

PubMed2001

Osteolipoma of the skull base.

Although lipomas are the most common benign tumours of the head and neck, the involvement of the skull base is rare and it is also very rare for a lipoma to undergo osseous metaplasia to become an ossifying lipoma or osteolipoma. We present a case of a solitary osteolipoma involving the skull base in a 17-year-old girl. A few cases of osteolipoma involving the head and neck have been reported, but this may be the first reported case of a solitary osteolipoma involving the skull base with extension to the infratemporal fossa and parapharyngeal space. The computed tomography (CT) scan helped to clinch the diagnosis and the histopathology confirmed it. The clinical presentation, role of CT scan, surgical approach used, histological features and the review of literature are discussed.

Adolescent↗

PubMed2001

Fas ligand expression by neoplastic T lymphocytes mediates elimination of CD8+ cytotoxic T lymphocytes in mycosis fungoides: a potential mechanism of tumor immune escape?

Mycosis fungoides (MF) is the most common form of cutaneous T-cell lymphoma (CTCL) and arises from the accumulation and clonal proliferation of epidermotropic, CD4+/CD45RO+ (helper/memory) T lymphocytes. Loss of CD8+ CTLs within MF lesions is associated with poor prognosis and disease progression. Because T-lymphocyte apoptosis is controlled mainly through the Fas/Fas ligand (FasL) pathway and tumor cells may escape immune surveillance by expressing FasL, triggering apoptosis of tumor-infiltrating T lymphocytes, we studied the role of this system in MF. T-cell subsets, Fas/FasL expression, and apoptosis were evaluated in normal and lesional skin biopsy specimens from 21 patients with all stages of MF and in cultured CTCL cell lines (MJ, HUT78, and HH) using immunohistochemistry, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and Western blotting. MF lesions and paired, clinically "normal," uninvolved skin showed increased numbers of both TUNEL-positive epidermal keratinocytes (n = 13; F = 31.146; P < 0.01, ANOVA) and dermal lymphocyte infiltrates (n = 13; F = 15.825, P < 0.01, ANOVA) compared with the normal control skin. FasL expression was highest in lesional epidermal keratinocytes, in CTCL tumor cell lines, and in dermal tumor lymphocytes in MF lesions compared with uninvolved skin. FasL colocalized with CD45RO+ cells. CD8+ cells in or adjacent to CD45RO+ cells were positively labeled by TUNEL for apoptosis. In addition, CD8+ cell numbers were decreased in areas in which FasL+ tumor cells were abundant (2.01 +/- 0.86%) compared with non-FasL expressing areas (13.53 +/- 3.54%; P < 0.02). These results suggest that a potential mechanism of tumor immune escape in MF is FasL-mediated apoptosis of infiltrating CD8+ CTLs.

Adult↗

PubMed2000

Rosai-Dorfman disease of the subglottis.

A case of subglottic narrowing caused by an extranodal deposit of sinus histiocytosis in a 29-year-old man is reported. The characteristic features of Rosai-Dorfman disease, such as massive painless cervical lymphadenopathy, fever, raised erythrocyte sedimentation rate and raised white cell count, were all found to be absent. However, typical histological features, such as diffuse lymphoplasmacytic infiltrate, Russel bodies, foamy histiocytes and histiocytes with emperipoiesis, confirmed the diagnosis. Rosai-Dorfman disease is an uncommon disorder and its presentation with progressive subglottic narrowing is extremely rare. Our experience in the management of this condition is reported and the review of literature is discussed.

Adult↗

PubMed2000

Expression of a retinoid-inducible tumor suppressor, Tazarotene-inducible gene-3, is decreased in psoriasis and skin cancer.

Tazarotene-induced gene-3 (TIG-3), isolated from human keratinocytes treated with the retinoic acid receptor-selective retinoid Tazarotene, is homologous to H-rev, a class II tumor suppressor. TIG-3 gene localized to chromosome 11q23, a site of loss of heterozygosity in several malignancies. Retinoids influence epidermal differentiation and are used to treat and prevent skin cancer. Therefore, we studied TIG-3 mRNA expression in psoriasis and in basal and SCCs by in situ hybridization and a quantitative QT-RT-PCR assay. Psoriasis lesions had significantly lower staining (median, 3) than paired normal control skin (median, 4; P = 0.012). TIG-3 mRNA was significantly higher in normal control skin (P = 0.001), in paired adjacent skin (median, 3; P = 0.007), and in overlying epidermis (median, 3.0; P = 0.0001) than in 21 SCC specimens as a group (median, 1.5).

Aged↗

PubMed1999

Flotillin 2 is distinct from epidermal surface antigen (ESA) and is associated with filopodia formation.

ECS-1, a monoclonal antibody (MoAb) raised to cultured human keratinocytes, stains the intercellular glycocalyx with a pemphigus-like pattern and recognizes a 35-kDa epidermal surface antigen (ESA) on Western blotting of keratinocyte extracts. When ECS-1 MoAb was used to screen a keratinocyte expression library, a unique cDNA was identified that predicted a 42-kDa globular protein of unknown function. This putative ESA was conserved between mice and humans and was encoded by a gene on chromosome 17q11-12 in linkage with neurofibromin. Homology between the cDNA sequence has been reported with flotillin 1, a caveolae associated protein, as well as Reggie 1 and 2, neuronal proteins expressed during axonal regeneration present in activated GPI-anchored cell adhesion molecules in non-caveolar-associated micropatches. In order to determine whether the cDNA predicted protein and ECS-1 antigen were identical, we compared ECS-1 with the immunoreactivity of a new antibody raised to the cDNA fusion protein in epidermis and cultured cells. The cDNA fusion protein was expressed in bacteria and in cos cells with his, FLAG, and EGFP reporter tags and by stable transfection as an EGFP fusion protein. The fusion protein and native protein of 42 kDa were detected by the new antibody, but not by the original ECS-1. Thus, the ECS-1 antigen, ESA (35 kDa), is clearly distinct from the protein predicted by the cDNA (renamed flotillin 2). Stable transfection of ESA/flotillin 2 fusion protein in cos cells induced filopodia formation and changed epithelial cells to a neuronal appearance. Thus, the function of flotillin 2 may resemble that of the goldfish optic nerve neuronal regeneration proteins, Reggie 1 and 2.

Animals↗

PubMed1999

Solitary adult myofibroma of the pinna.

Solitary myofibroma is a recently described benign neoplasm of the skin or superficial soft tissue and it represents the adult counterpart of infantile myofibromatosis. This new clinicopathological entity is being recognized increasingly. A case of solitary myofibroma occurring in the pinna of a 50-year-old woman is presented. Such a lesion occurring in the pinna of an adult has not been reported in the literature.

Ear Neoplasms↗

PubMed1998

Prevention and management of synechia in pediatric endoscopic sinus surgery using dental wax plates.

Synechia formation is a very common complication of endoscopic sinus surgery (ESS). Inspite of meticulous post-operative care, synechia do form in quite a large number of patients. Moreover, frequent post-operative cleaning may not be possible without general anesthesia in non-compliant patients, especially children. This study compares the incidence of synechia following pediatric ESS with or without spacer/tamponade in the operated cavity. The authors have found dental wax plates to be equally effective and more economical spacers compared to Merocel tamponade, in prevention and management of synechia in the pediatric age group.

Case-Control Studies↗

PubMed1998

Dual ectopic thyroid: a report of two cases.

Ectopic thyroid is an uncommon embryological aberration characterized by the presence of thyroid tissue at a site other than in its usual pretracheal region. Usually it occurs along the path of descent of the developing thyroid primodium from the foramen caecum, commonest being lingual followed by sublingual and in the anterior midline of neck at, or below, the level of the hyoid bone. It is unusual for lingual thyroid to present simultaneously with another ectopic thyroid; reported here are two such cases.

Adolescent↗

PubMed1996

Giant neurofibroma of the tongue.

Neurofibroma of the tongue arising from the hypoglossal nerve is rare [7], but a combined neurofibroma of the hypoglossal and lingual nerve is extremely rare in the English literature to our knowledge [4,6]. Here one such case is being presented for its rarity, peculiarity of its clinical presentation and the surgical approach to excise it.

Adolescent↗

PubMed1996

Interleukin-8 is induced in skin equivalents and is highest in those derived from psoriatic fibroblasts.

Interleukin-8 (IL-8) may be important in psoriasis as it is expressed in the stratum granulosum, attracts polymorphonuclear cells, and stimulates angiogenesis and keratinocyte mitogenesis. To study intrinsic cutaneous factors in psoriasis, we constructed skin equivalents from psoriatic or adult control fibroblasts with normal foreskin keratinocytes. IL-8 levels were measured in supernatants by enzyme-linked immunosorbent assay and in skin equivalents by immunohistochemistry and in situ hybridization. IL-8 was highly induced in skin equivalents compared to cells grown alone. Epidermal stratification varied among fibroblast lines and was correlated with IL-8 levels, but lesional and nonlesional psoriatic skin equivalents from the same donor were similar. Six fibroblast lines (two psoriasis lesion and four normal) supported only monolayers, while 12 lines (seven psoriasis lesion and five normal) produced stratification. Mean IL-8 levels were significantly lower in dermal equivalents of the first group than the second (0.78 +/- 0.40 vs 3.93 +/- 2.83 ng per ml, mean +/- SD, p = 0.01, analysis of variance). Significantly more IL-8 was secreted by psoriatic than normal fibroblast skin equivalents over 14 d (p = 0.015) with greatest differences at 1 and 4 d. Psoriatic IL-8 levels peaked first and remained increased. IL-8 protein and mRNA were initially strongest in dermal fibroblasts, and at the dermal-epidermal interface. Diffuse epidermal expression was replaced by accentuation in the stratum granulosum. Psoriatic skin equivalents were thicker, had more intense IL-8 staining, and developed invagination. We hypothesize that an IL-8 paracrine loop between fibroblasts and keratinocytes may play a key role in epidermal regeneration in the skin equivalent, in normal wound healing, and in the determination of an intrinsic psoriatic wound-healing phenotype.

Adult↗

PubMed1996

Hearing anomalies following radiation therapy for head and neck cancers.

Ionizing radiation used for the treatment of head and neck tumors affected epithelial and connective tissue. Epithelial lining of the middle ear mucosa desquamated, when exposed to conventional dose of radiation. Mucosa becomes oedematous which subsequently lead to formation and collection of sterile fluid within middle ear cavity and thus producing radiation otitis media with conductive deafness. Radiation induced changes in the structure surrounding the end organs of hearing such as vascular and connective tissue alterations which later eventually could affect the end organ leading to perceptive type of hearing loss as a result of chronic anoxia to end organ.

Head and Neck Neoplasms↗

PubMed1995

Osteogenic sarcoma of sphenoid bone: an extended lateral skull base approach.

Osteogenic sarcoma involving the sphenoid bone is an extremely rare condition. The rarity of the disease and the close proximity of the sphenoid bone to the various important intracranial structures poses a real challenge in diagnosis and surgical management of these lesions. An extended lateral craniofacial resection by a multidisciplinary approach was carried out in one such case to attempt en bloc resection. This case is presented and also a review of the relevant literature.

Adult↗

PubMed1994

Foreign body in the ethmoid sinus.

An air gun pellet lodged in the posterior ethmoid sinus in a 1-year-old child is described. Functional endoscopic sinus surgery enabled the removal of the pellet, obviating an external ethmoidectomy.

Endoscopy↗

PubMed1994

Invasive maxillary aspergillosis in an otherwise healthy individual.

Invasive aspergillosis is usually seen in immunocompromised individuals. We report the case of a 56-year-old immunocompetent housewife with Aspergillus niger invading the ethmoid and sphenoid sinuses and extending to the anterior cranial fossa. A. niger grew on three occasions (from the biopsy, mass and dura mater). In spite of medial maxillectomy and ethmoidectomy followed by craniofacial resection and antifungal drugs (amphotericin B) the patient died on tenth post-operative day.

Aspergillosis↗