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Biomedical subjects

A K Banerjee

Publications and source records attributed to A K Banerjee.

At least 37 records · Page 2Linked to original sources
PubMed2002

Rabies viral antigen in extracranial organs: a post-mortem study.

Rabies is a communicable disease and a significant health hazard. Histopathological confirmation of the diagnosis depends on the demonstration of Negri bodies - characteristic intracytoplasmic inclusions. In cases where these are not seen, immunohistochemistry serves as a useful adjunct. After its establishment in the central nervous system, the rabies virus is known to reach peripheral organs by a centrifugal spread. The present study was undertaken with the aim of demonstrating rabies viral antigen (RVAg) in the extracranial organs. Eleven confirmed cases of rabies were analysed and RVAg was found in the adrenal glands, heart, gastrointestinal tract and pancreas, confirming the centrifugal spread of the virus. The detection of RVAg in the extracranial sites may serve as a useful tool in the ante-mortem diagnosis by subjecting the extracranial tissue to biopsy and subsequent immunohistochemistry.

Adrenal Glands↗
PubMed2002

Common variable immune deficiency: respiratory manifestations, pulmonary function and high-resolution CT scan findings.

BACKGROUND: Common variable immune deficiency (CVID) is prone to under-diagnosis and may not reach relevant specialists until late in life. Morbidity is most commonly due to acute-on-chronic respiratory infections leading to respiratory failure. AIM: To investigate respiratory complications, lung function and high-resolution computerized tomography scan (HRCT) findings and mortality in 47 patients with CVID. SETTING: A regional immunology unit (Birmingham Heartlands Hospital). DESIGN: Retrospective observational case-note study following the introduction of shared care between immunology and respiratory medicine. RESULTS: Age at diagnosis ranged from 5 to 72 years, with a median time from development of first symptoms to diagnosis of 4.0 years. There was delay in referral between chest physicians and immunologists, (median referral time between specialities >5 years). Forty-two patients had respiratory complications, due to bronchiectasis (n=32), asthma (n=7), recurrent chest infections (n=9) without concomitant evidence of structural lung damage, and granulomatous lung disease (n=2). Spirometry was abnormal in 10/39 patients (7 obstructive, 3 restrictive). Bronchiectasis was confirmed on chest radiograph (n=9) and HRCT (n=24). Despite the high prevalence of bronchiectasis, few patients had received instruction in physiotherapy and sputum culture results were sparse. DISCUSSION: To reduce the morbidity associated with CVID, there needs to be greater awareness of respiratory complications, particularly amongst physicians caring for such patients. Emphasis has been placed on adequate dosage of immunoglobulin, but early involvement by a respiratory physician is essential to monitor lung function and initiate optimal therapy, to minimize the occurrence and progression of lung damage.

Adult↗
PubMed2001

Lymph node cytology in Wegener's granulomatosis.

We report on cytological findings on aspirates from the cervical lymph node from a case of Wegener's granulomatosis (WG). The diagnostic utility of technique in diagnosing a sizable minority of WG patients who present with cervical lymphadenopathy is discussed. We outline an approach to diagnosis of necrotising granulomatous lesions in aspirates from lymph nodes in a tabular form.

Adolescent↗
PubMed2001

Absence of abdominal pain in older persons with endoscopic ulcers: a prospective study.

OBJECTIVE: In a retrospective study we reported absence of abdominal pain in 35% of elderly patients with peptic ulcer disease. We now report a prospective study on this question. METHODS: Patients undergoing upper GI endoscopy were systematically questioned before endoscopy. A reproducible method for identifying the location of symptoms was used. Among patients referred for upper endoscopy, there was no selection of patients for study purposes as all had strong indications, such as pain, dyspepsia, GI bleeding, weight loss, or anemia. Patients were divided into two groups according to age: A younger group consisting of patients <50 yr (mean, 33.6 yr) and an older group >60 yr (mean, 70.9 yr). RESULTS: A total of 277 patients were included in the study. There was no significant difference in reported use of medications, alcohol, or cigarette use between the groups. Of the 106 patients with peptic ulcer, 15 (14.2%) had not experienced pain. Abdominal pain was absent in 5 (6.9%) of the younger patients and 10 (29.4%) of the older patients. The difference was significant using the chi2 method (p = 0.004). A trend toward an even higher proportion of pain-free peptic ulcer disease was noted in the elderly female group (37.5%), but it did not reach statistical significance. CONCLUSIONS: Absence of abdominal pain is confirmed in approximately 30% of elderly patients with peptic ulcer disease.

Abdominal Pain↗
PubMed2001

Human parainfluenza virus type 3 inhibits gamma interferon-induced major histocompatibility complex class II expression directly and by inducing alpha/beta interferon.

Human parainfluenza virus type 3 (HPIV3) is one of the major causes of bronchiolitis, pneumonia, and croup in newborns and infants. Cellular immunity involving major histocompatibility complex (MHC) class I and class II molecules plays an important role in controlling virus infection. Several viruses have been shown to down-regulate gamma interferon (IFN-gamma)-mediated MHC class II expression. In this communication, we show that HPIV3 strongly inhibits the IFN-gamma-induced MHC class II expression in HT1080 human fibrosarcoma cells. The culture supernatant of HPIV3-infected cells also inhibited IFN-gamma-induced MHC class II expression, a phenomenon that was found to be due, in large part, to alpha/beta interferon (IFN-alpha/beta). Expression of MHC class I and intercellular adhesion molecule 1 occurred efficiently in cells simultaneously infected with HPIV3 and treated with IFN-gamma, indicating that the inhibitory effect of HPIV3 was specific to MHC class II. STAT1 activation was not affected by HPIV3 at early postinfection times but was partially inhibited at later times. These data suggested that the potent inhibition of MHC class II expression was, in major part, due to a defect downstream of STAT1 activation in the IFN-gamma-induced MHC class II expression pathway. Class II transactivator (CIITA) is the unique mediator of IFN-gamma-induced transcription from the MHC class II promoter. By RNase protection analysis, CIITA expression was found to be strongly inhibited in HPIV3-infected cells. The culture supernatant containing IFN-alpha/beta, on the other hand, inhibited MHC class II expression without affecting STAT1 and CIITA expression. These data indicate that HPIV3 inhibits IFN-gamma-induced MHC class II expression primarily by the viral gene products targeting CIITA and additionally by inducing IFN-alpha/beta to target one or more steps further downstream.

Animals↗
PubMed2001

Polarity of human parainfluenza virus type 3 infection in polarized human lung epithelial A549 cells: role of microfilament and microtubule.

Human parainfluenza virus type 3 (HPIV-3) is an airborne pathogen that infects the epithelial cells of the respiratory tract. In the present study we investigated the interaction of HPIV-3 with the type II alveolar human lung polarized epithelial A549 cells. Although HPIV-3 entry and budding were bidirectional from both the apical and the basolateral domains, HPIV-3 exhibited preferential entry and release from the apical pole. While disruption of the cellular actin microfilament and microtubule by cytochalasin D and nocodazole, respectively, had no effect on virus entry, disruption of the microtubule but not the microfilament inhibited HPIV-3 release.

Actin Cytoskeleton↗
PubMed2001

Neuropathological complications of infective endocarditis : study of autopsy material.

78 autopsy proven cases of infective endocarditis (IE) seen during 1983 to 1995 were retrospectively reviewed. The brain was available for examination in 44 cases. In the remaining cases, brain was not examined because examination of it was not requested due to lack of neurological findings. Brain lesions were observed in 35 out of 44 cases of IE. Assuming remaining 34 cases to be without brain lesions, the brain involvement in IE would be 44.87% (35 out of 78 cases). Mean age of all cases of IE and those with brain lesions was similar i.e. 26.5+/-16.6 years and 26.6+/-13.06 years respectively. Largest number of cases with neuropathological lesions were associated with normal valve IE (48.57%). Mitral valve was most commonly involved in cases with CNS complications (57.14%) (p<0.05). The various types of brain lesions were infarction (68.57%), haemorrhage (57.14%), cerebral micro-abscess (31.42%) and focal meningitis (14.28%). More than one type of lesion was observed in 19 cases, indicating complicated nature of brain lesions in fatal cases of IE. Left sided middle cerebral artery (MCA) territory was the commonest site of infarction and haemorrhage. Staphylococcus aureus appeared to be the most common organism in fatal cases of IE. Normal valve IE with or without CNS complications constitutes a significant group in India and is different from the west as far as the predisposing conditions are concerned.

Adolescent↗
PubMed2001

Cerebral abscess with astrocytoma.

A child with a right parieto-occipital astrocytoma, caped by a large acute pyogenic abscess with flimsy capsule, detected at emergency craniotomy, is presented. Patient succumbed to the disease three hours following surgery.

Astrocytoma↗
PubMed2001

Flowcytometric and histopathological correlation of primary intracranial neoplasms.

DNA ploidy and synthetic phase fraction (SPF) of 52 cases of primary intracranial neoplasms have been determined from fresh tissues and the data was correlated with histopathological typing and grading. Fresh tumour tissues from 52 random surgical biopsies (28 malignant and 24 benign) were obtained from neurosurgical operations during the period 1994-1996. The cells were analysed in Becton Dickinson flowcytometer fitted with Consort 30 programme and 'Sober' software. Percentage of diploid cells, proliferative cells and DNA aneuploidy were evaluated. The tumours were classified and graded according to WHO classification (1993). On histology, there were 28 malignant (grade II to IV) and 24 benign cases (grade I). All the histologically benign tumours in this study showed diploid DNA content with the exception of a pituitary adenoma which had a heterogeneous population of cells. The S phase fraction in all the benign cases was less than 10% except in the case of choroid plexus papilloma (S-phase 54%) and an atypical meningioma (S-phase 14%). Out of the 28 malignant tumours, 12 cases were aneuploid (43%) and the rest were diploid (57%). Among the 16 diploid tumours, SPF was more than 10% in eight cases. DNA aneuploidy and high SPF are more common in histologically malignant tumours than benign tumours. SPF is a reflection of proliferation potential of a tumour and may have some role in prognostication of brain tumours.

Brain Neoplasms↗
PubMed2001

Gastrointestinal stromal tumors the assessment of malignant potential.

GISTS are the largest category of non-epithelial neoplasms of stomach and small bowel. Numerous immunohistochemical, ultrastructural and flow cytometry studies have been carried out for evaluation of prognostic factors which could predict malignant behaviour of these neoplasms. Tumor size of 5 cm and mitosis of 2/10 hpf were suggested as two important parameters which could predict the chances of recurrence and clinically aggressive course. The aim of this study is to examine predictive value of these two important parameters in assigning the tumors as high, intermediate and low risk groups. Using these two parameters we categorized 30 cases of GIST over a period of 6 years (1990-95) into low, intermediate and high risk groups and examined other features of these cases. Based on these two parameters alone we found that 4 cases each in low and intermediate group could be assigned to a higher risk group clinically as there were presence of adjacent organ infiltration, lymphatic emboli, serosal nodules, lymph node metastasis and transmural infiltration. Hence, other features like hemorrhage, necrosis and anaplasia should also be included in risk assessment. Metaplastic tissues like bone, cartilage and adipose tissues were seen only in high-risk categories.

Adolescent↗
PubMed2000

Analysis of RNA secondary structure in replication of human parainfluenza virus type 3.

The terminal RNA regions of the genomic and antigenomic RNAs of the paramyxoviruses and rhabdoviruses are known to contain sequences essential for RNA replication and transcription. The 3'- and 5'-termini of human parainfluenza virus type 3 (HPIV3) genomic RNA, termed leader and trailer sequences, respectively, are capable of forming stable stem-loop structures. Additionally, the 17 terminal bases of the leader and trailer are complementary and therefore also capable of forming a helical structure. We investigated the roles of the stem-loop structure and terminal complementarity in HPIV3 RNA replication and transcription in vivo using a minigenome containing all RNA elements necessary for these processes. By mutational analysis, we show that the RNA secondary structure features present at the termini of HPIV3 have no discernible role in replication or transcription. Rather, the primary sequence of these regions is what is critical in promoting replication. Interestingly, a mutation at leader base 24 was found to revert a mutation at leader position 5 but probably not via RNA secondary structure restoration.

Base Pairing↗
PubMed2000

Precise mapping of the replication and transcription promoters of human parainfluenza virus type 3.

The terminal RNA regions of the genomic and antigenomic RNAs of the paramyxoviruses and rhabdoviruses are known to contain sequences essential for directing RNA replication and transcription. The 3' terminus (leader region) of the negative-sense, genomic RNA of the rhabdoviruses and paramyxoviruses is known as the leader (Le) promoter and directs synthesis of positive-sense replication and transcription products. The 3' terminus of the antigenome is termed the trailer complementary (TrC) promoter and directs the synthesis of genomic RNA. By creating mutations in the corresponding regions of an HPIV3 minireplicon in which the viral protein coding sequences were replaced by the luciferase gene, we were able to precisely define the elements of the leader promoter involved in directing positive-strand replication of HPIV3. Nucleotides 1 through 12 (from the terminus) formed a domain critical for replication. The region from nucleotides 13 through 55 was important but not crucial for replication, while G residues at positions 79, 85, and 91 comprised another domain critical for replication. It was also shown that the TrC promoter is similar, though not identical, to the Le promoter. Nucleotides 1 through 12 of the TrC promoter were critical for synthesis of genomic RNA, though specific positions behaved differently from the corresponding positions of the Le promoter. While many of these mutations could not be analyzed for transcription because they completely abrogated genomic RNA synthesis (the template for transcription), we were surprised to find that no mutations in the leader promoter which decreased replication had any significant effect on transcription. However, mutations in the intergenic sequence and gene start signal following the leader and preceding the luciferase message severely decreased transcription, but not replication.

Base Sequence↗
PubMed2000

Immunohistochemical study of human rabies.

Rabies is a communicable disease that is almost always fatal. In its classic form, rabies is well recognized, but cases presenting with a paralytic illness mimic Landre's Guillain-Barre syndrome and in such cases the diagnosis remains in doubt. This problem is further compounded when the history of dogbite is not forthcoming. At autopsy rabies can be diagnosed by subjecting fresh tissue to virologic investigations or examining formalin-fixed paraffin-embedded tissue sections for the presence of characteristic inclusions; that is, the Negri bodies. However, these inclusions are not present in all cases. Hence, the need arises for a better method for diagnosis. The present study utilized immunohistochemistry as a diagnostic tool using both monoclonal and polyclonal antirabies antibodies in 20 cases of rabies encephalomyelitis. The diagnosis of rabies could be confirmed in 17 cases (85%) based on neuropathologic findings alone. In contrast, immunohistochemistry yielded positive results in all cases. Moreover, the amount of rabies viral antigen was much more abundant than could be expected from the histopathologic findings. Thus immunohistochemistry is a rapid, safe, sensitive and specific technique for the diagnosis of rabies.

Adolescent↗
PubMed2000

The phosphoprotein of rabies virus is phosphorylated by a unique cellular protein kinase and specific isomers of protein kinase C.

The phosphoprotein (P) gene of rabies virus (CVS strain) was cloned and expressed in bacteria. The purified protein was used as the substrate for phosphorylation by the protein kinase(s) present in cell extract prepared from rat brain. Two distinct types of protein kinases, staurosporin sensitive and heparin sensitive, were found to phosphorylate the P protein in vitro by the cell extract. Interestingly, the heparin-sensitive kinase was not the ubiquitous casein kinase II present in a variety of cell types. Further purification of the cell fractions revealed that the protein kinase C (PKC) isomers constitute the staurosporin-sensitive kinases alpha, beta, gamma, and zeta, with the PKCgamma isomer being the most effective in phosphorylating the P protein. A unique heparin-sensitive kinase was characterized as a 71-kDa protein with biochemical properties not demonstrated by any known protein kinases stored in the protein data bank. This protein kinase, designated RVPK (rabies virus protein kinase), phosphorylates P protein (36 kDa) and alters its mobility in gel to migrate at 40 kDa. In contrast, the PKC isoforms do not change the mobility of unphosphorylated P protein. RVPK appears to be packaged in the purified virions, to display biochemical characteristics similar to those of the cell-purified RVPK, and to similarly alter the mobility of endogenous P protein upon phosphorylation. By site-directed mutagenesis, the sites of phosphorylation of RVPK were mapped at S(63) and S(64), whereas PKC isomers phosphorylated at S(162), S(210), and S(271). Involvement of a unique protein kinase in phosphorylating rabies virus P protein indicates its important role in the structure and function of the protein and consequently in the life cycle of the virus.

Animals↗
PubMed2000

Role of NH(2)- and COOH-terminal domains of the P protein of human parainfluenza virus type 3 in transcription and replication.

The phosphoproteins (P proteins) of paramyxoviruses play a central role in transcription and replication of the viruses by forming the RNA polymerase complex L-P and encapsidation complex (N-P) with nucleocapsid protein (N) and binding to N protein-encapsidated genome RNA template (N-RNA template). We have analyzed the human parainfluenza virus type 3 (HPIV3) P protein and deletion mutants thereof in an in vitro transcription and in vivo replication system. The in vitro system utilizes purified N-RNA template and cell extract containing L and P proteins coexpressed via plasmids using a recombinant vaccinia virus expression system. The in vivo system takes advantage of minigenome replication, which measures luciferase reporter gene expression from HPIV3 minigenomes by viral proteins in a recombinant vaccinia virus expression system. These studies revealed that the C-terminal 20-amino-acid region of P is absolutely required for transcription in vitro and luciferase expression in vivo, suggesting its critical role in viral RNA synthesis. The N-terminal 40-amino-acid region, on the other hand, is essential for luciferase expression but dispensable for transcription in vitro. Consistent with these findings, the C-terminal domain is required for binding of P protein to the N-RNA template involved in both transcription and replication, whereas the N-terminal domain is required for the formation of soluble N-P complex involved in encapsidation of nascent RNA chains during replication. Coimmunoprecipitation analysis showed that the P protein forms a stable homooligomer (perhaps a trimer) that is present in L-P and N-P complexes in the higher oligomeric forms (at least a pentamer). Interestingly, coexpression of a large excess of N- or C-terminally deleted P with wild-type P had no effect on minigenome replication in vivo, notwithstanding the formation of heterooligomeric complexes. These data indicate that P protein with a deleted terminal domain can function normally within the P heterooligomeric complex to carry out transcription and replication in vivo.

Cell Line↗