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Biomedical subjects

A R Choudhury

Publications and source records attributed to A R Choudhury.

At least 19 recordsLinked to original sources
PubMed2004

Crystal engineering via C-H...F and C-H...pi interactions in two substituted indoles.

The crystal structures of 1-(4-fluorophenyl)-2-phenyl-4,5,6,7-tetrahydro-1H-indole, C20H18FN, and 1-(4-fluorophenyl)-6,6-dimethyl-2-phenyl-4,5,6,7-tetrahydro-1H-indole, C22H22FN, have been determined in order to study the role of 'organic fluorine' in crystal engineering. These molecules pack in the crystal structure via different types of molecular motifs utilizing weak C-H...F and C-H...pi interactions.

Journal Article↗
PubMed2004

An analysis of C-H...O and C-H...pi interactions in three substituted 4-ketotetrahydroindoles.

The crystal and molecular structures of the three 4-ketotetrahydroindoles 2-(4-chlorophenyl)-1-(4-fluorophenyl)-6,6-dimethyl-4,5,6,7-tetrahydro-1H-indol-4-one (C22H19ClFNO), (I), 1-(4-fluorophenyl)-2-(4-methoxyphenyl)-6,6-dimethyl-4,5,6,7-tetrahydro-1H-indol-4-one (C23H22FNO2), (II), and 6,6-dimethyl-1,2-diphenyl-4,5,6,7-tetrahydro-1H-indol-4-one (C22H21NO), (III), have been determined via single-crystal X-ray diffraction in order to study the intermolecular interactions therein. All three structures are stabilized via intermolecular C-H...O and C-H...pi interactions, generating different molecular motifs.

Journal Article↗
PubMed2003

Two biologically active thiophene-3-carboxamide derivatives.

The two title compounds, 2-([(1Z)-[4-(dimethylamino)phenyl]methylene]amino)-4,5-dimethyl-N-(2-methylphenyl)thiophene-3-carboxamide, C(23)H(25)N(3)OS, (I), and 2-([(1E)-[4-(dimethylamino)phenyl]methylene]amino)-N-(4-methylphenyl)-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide,C(25)H(27)N(3)OS, (II), show antibacterial and antifungal activities. The asymmetric unit of (II) contains two crystallographically independent molecules. The o-toluidine ring in (I) lies gauche with respect to the thiophene ring. In (II), the p-toluidine ring is coplanar with the thiophene ring in one molecule, but is tilted from it in the other molecule. Neither structure exhibits any significant intermolecular interactions, but in both, an intramolecular N-H.N hydrogen bond forms a pseudo-six-membered ring, thus locking the molecular conformation and removing conformational flexibility.

Aniline Compounds↗
PubMed2000

Ameloblastic fibroma in the midline of mandible: a case report.

The ameloblastic fibroma (AF) is a rare benign mixed odontogenic tumor. It is composed of both epithelial and mesenchymal elements, but lacks of any calcified dental structures. Most of these tumors occur in the mandible and appears preferentially in the posterior portion of the dental arch with molar area predominates over premolar area. It is important to differentiate the lesion from ameloblastoma, since unlike the latter, it does not exhibit a locally invasive growth pattern. It is a well-circumscribed lesion and does not require the radical excision that may be necessary to effect cure with ameloblastoma. The present case report describes a 15-year-old patient with an ameloblastic fibroma in the symphysis of the mandible, a rare reported site. In the beginning of the article an extensive review of the previously published literature on ameloblastic fibroma has been made. In the later part, the diagnosis, differential diagnosis, histology and therapeutic procedures and postoperative follow up of the present case have been described.

Adolescent↗
PubMed1999

Cerebral heterotopia of the temporofacial region. Case report.

The authors report a case of cerebral heterotopia in the right temporofacial region of a neonate. The lesion presented as a massive cystic swelling containing cerebrospinal fluid. It produced calvarial and facial bone deformities. After the mass was excised, histological examination revealed glial tissue and choroid plexus.

Brain Diseases↗
PubMed1997

Mustard oil and garlic extract as inhibitors of sodium arsenite-induced chromosomal breaks in vivo.

Arsenic, a well-known human carcinogen present as a contaminant in ground water poses a serious threat to public health in various countries. The anticlastogenic properties of two dietary supplements, garlic and mustard oil, were screened against the clastogenic activity of sodium arsenite, since diet may contain factors which affect the process of mutagenesis and carcinogenesis. Aqueous extract of garlic (100 mg/kg b.w.) and mustard oil (0.643 mg/kg b.w.) were fed to Mus musculus for 30 consecutive days either singly or simultaneously. Sodium arsenite (0.1 mg/kg b.w.) was injected subcutaneously on days 7, 14, 21 and 30 of the experiment, singly and together with the dietary supplements. The animals were sacrificed 24 h after the last exposure to sodium arsenite and clastogenic effects were observed in the bone marrow cells. The degree of modulation of sodium arsenite-induced chromosomal aberrations was more pronounced in mustard oil than in garlic extract and simultaneous administration of both the dietary supplements reduced the clastogenic effects of sodium arsenite closer to the level of the negative control. The greater efficacy could be due to the interaction of the two dietary supplements and its radical scavenging property.

Animals↗
PubMed1997

Inhibition of clastogenic effects of arsenic through continued oral administration of garlic extract in mice in vivo.

Crude aqueous extract of garlic bulbs (Allium sativum L. single clove variety) was administered by gavage to mice of both sexes daily for up to 30 and 60 days, in doses corresponding to 6 g for a 60 kg human body. Sodium arsenite (at 1/50 of LD50 dose) was injected subcutaneously to mice on every 7th day of the experiment. Chromosome preparations made from bone marrow following flame drying Giemsa schedule were screened for chromosomal aberrations. The clastogenic affects of prolonged exposure to sodium arsenite --a strong clastogen-- was reduced by a highly significant amount when crude garlic extract, in the dose used, was given daily to the mice by intubation for the same period.

Administration, Oral↗
PubMed1996

Heterotopic spinal cord? A curiosity.

Unusual morphological findings were encountered in a high cervical meningomyelocele sac of a neonate. Magnetic resonance imaging revealed a massive liquid-filled sac traversed by a linear structure. The spinal cord was seen to be located normally within the spinal canal. At operation, a spinal cord-like structure was identified within the sac. This cord terminated posteriorly at the neural tissue lining the meningomyelocele sac. There were fibrous strands connecting the cord to the sac like the rigging of a ship. The anterior end of this cord terminated in a fibrous band. It extended upwards into the spinal canal through the narrow neck of the meningomyelocele sac above the arch of the atlas. The whole of this cord, along with the meningomyelocele sac, was excised. Histological analysis confirmed that this spinal cord-like structure consisted of glial tissue with an ependymal-lined cavity. The excised sac was lined by neural tissue.

Choristoma↗
PubMed1996

Glial heterotopias of the nose: a report of two cases.

Two neonates are presented who had glial heterotopias of the nose, one with and the other without intracranial connections. It is important to distinguish these malformations from nasofrontal encephaloceles in order to avoid inadvertent exposure of the brain during surgical removal of the mass lesions. The distinction between them may not be clear clinically because of their similar pathogenesis.

Choristoma↗
PubMed1996

Effects of crude garlic extract on mouse chromosomes in vivo.

Three concentrations (25, 50 and 100 mg/kg body weight) of fresh garlic (Allium sativum L.) were administered daily by gavage to Swiss albino mice for different durations up to 60 days. These concentrations had been observed to protect significantly against effects of known clastogens. The endpoints scored were frequencies of chromosomal aberrations and damaged cells induced in bone marrow preparations. These parameters were found to be directly dose dependent and after an initial enhancement at 7 days, were reduced following prolonged exposure for 30 and 60 days to the low level observed at 24 hr. Therefore, administration of a low concentration of garlic extract daily is suggested for at least 30 days to obtain the maximum benefit of the extract in protecting against the clastogenic effects of known genotoxicants.

Administration, Oral↗
PubMed1995

Dexamethasone or cyclosporin A suppress mast cell-leukocyte cytokine cascades. Multiple mechanisms of inhibition of IgE- and mast cell-dependent cutaneous inflammation in the mouse.

In allergic diseases, exposure of sensitized subjects to allergen induces the activation of tissue mast cells that results in an immediate-type hypersensitivity response and, in some individuals, a a late phase response. We previously have reported that the neutrophil infiltration associated with IgE-dependent cutaneous inflammation in mice is mast cell-dependent and that TNF-alpha contributes significantly to this response. We report here that either dexamethasone or cyclosporin A can inhibit mouse mast cell TNF-alpha production in vitro, and that these agents also can significantly suppress the tissue swelling and leukocyte infiltration associated with two forms of TNF-alpha-associated inflammation in vivo: the entirely IgE- and mast cell-dependent inflammation at sites of passive cutaneous anaphylaxis reactions and the entirely TNF-alpha-dependent inflammation that is elicited by the direct intradermal injection of recombinant mouse TNF-alpha. Taken together, our in vitro and in vivo findings in mice indicate that dexamethasone or cyclosporin A can have at least three actions that interfere with the pathogenesis of IgE, mast cell, and cytokine-dependent inflammatory reactions:suppression of the IgE-dependent increase in TNF-alpha mRNA by mast cells, inhibition of the IgE-dependent production of TNF-alpha protein by mast cells, and diminution of the responsiveness of target cells to TNF-alpha. Our findings in mice raise the possibility that similar actions of these agents in humans may account for some of the clinical efficacy of corticosteroids and cyclosporin A in allergic diseases.

Animals↗
PubMed1995

Infantile hydrocephalus: management using CT assessment.

When determining a management plan for infantile hydrocephalus, the determining factor for or against the implantation of a shunt is the degree of ventricular dilatation. The author has devised a standardised method of estimating this, the use of which has been shown to achieve consistently successful results. Dilatation was determined using the ventricular/biparietal (V/BP) ratio from the axial CT scan at the mid-portion of the bodies of the lateral ventricles, showing the greatest ventricular dilatation. According to this method, hydrocephalus was classified into four grades. These were mild (V/BP ratio 0.26-0.40), moderate (V/BP ratio 0.41-0.60), severe (V/BP ratio 0.61-0.90) and extreme (V/BP ratio 0.91-1). A V/BP ratio of less than 0.26 was considered normal. This method appeared to be accurate and reproducible in infants with hydrocephalus including those with asymmetrical and multiloculated ventricular dilatation. In all the patients with mild hydrocephalus, spontaneous regression or stabilisation occurred and their developmental outcome was normal. Patients with moderate and severe hydrocephalus needed a ventricular shunt and the developmental outcome was satisfactory in 87% of the cases. They were functionally normal although 18 had some abnormal neurological signs. In patients with extreme hydrocephalus the developmental outcome following shunting was satisfactory in 31% of the cases. They were functionally normal although four had abnormal neurological signs. This plan of management was used in a total of 144 infants and it proved to be highly successful.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1995

Benign osteoblastoma of the parietal bone.

A 5-year-old girl presented with a 1-year history of a subcutaneous swelling in the right parietal region. There were no cerebral symptoms or signs. Plain X-ray of the skull showed a lytic bony lesion with sclerotic margin. Computed tomography showed a hypodense, osteolytic lesion with thinned and bulged inner and outer skull tables with intact continuity. There was no intracranial lesion. At operation, the mass was found to be pink and granular, and was totally enucleated. Histology revealed it to be a benign osteoblastoma.

Child, Preschool↗
PubMed1995

Solitary intradural intracranial osteoma.

A 20-year-old woman presented with a 4-month history of persistent right frontotemporal headache. There were no features of raised intracranial pressure. Plain radiographs of the skull showed a dense calcified mass in the right frontal area. Computed tomography revealed the lesion to be uniformly hyperdense and non-enhancing. Magnetic resonance imaging confirmed the dural origin of the lesion which was hyperintense and non-enhancing. At operation a bony hard intradural mass was confirmed and excised. Histology revealed it to be an osteoma.

Adult↗
PubMed1994

Avoidable factors that contribute to complications in the surgical treatment of chronic subdural haematoma.

The results of a personal series of 44 consecutive patients undergoing burrhole evacuation and closed system suction drainage for chronic subdural haematoma are presented. 43 patients made a complete recovery and one was left with moderate disability. Contralateral weakness in one patient, recurrence of haematoma in another, and a new contralateral haematoma in a third were the only complications. The operative procedures responsible for the rather low complication rate in this series are described. It is concluded that to avoid complications following surgical treatment of chronic subdural haematoma, attention must be paid to the following factors: evacuation of the haematoma through two burrholes overlying the subdural collection; attention to ensure free communication through the subdural space between the two burrholes; identification and opening of additional loculations overlying the cortex; irrigation of the subdural space to ensure as complete an evacuation of the subdural collection as possible and the use of closed system suction drainage, nursing the patient flat, and intravenous hydration of the patient for three days. In addition, in patients with coagulopathy, correction of these disorders before surgery is most essential.

Adolescent↗