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Biomedical subjects

A Garg

Publications and source records attributed to A Garg.

At least 37 records · Page 2Linked to original sources
PubMed2004

Scalp malignant peripheral nerve sheath tumor (MPNST) with bony involvement and new bone formation: case report.

Malignant peripheral nerve sheath tumors (MPNSTs) are rare neoplasms, usually arising from somatic soft tissues or peripheral nerves. Primary MPNST of the scalp is extremely rare, with only a single case reported so far. Here, we describe an unusual case of scalp MPNST in a 50-year-old male. The tumor was associated with bony projection, intracranial extension and underlying bone destruction. The tumor was treated with complete surgical excision followed by adjuvant radiotherapy. Histologically, the tumor showed malignant spindle cells with focal S-100 positivity on immunohistochemistry and a diagnosis of MPNST was made. This case is being reported for its rarity and presence of associated bony projection, which to the best of our knowledge, has not been described before in soft tissue sarcomas.

Head and Neck Neoplasms↗
PubMed2004

Genetic basis of congenital generalized lipodystrophy.

Congenital generalized lipodystrophy (CGL) is an autosomal recessive disorder characterized by extreme lack of body fat and severe insulin resistance since birth. Recently, mutations have been reported in 1-acylglycerol-3-phosphate-O-acyltransferase 2 (AGPAT2) and Berardinelli-Seip congenital lipodystrophy 2 (BSCL2 or Seipin) genes in affected subjects from pedigrees linked to chromosomes 9q34 and 11q13, respectively. The AGPAT2 catalyses the acylation of the lysophosphatidic acid at the sn-2 position to form phosphatidic acid, a key intermediate in the biosynthesis of triacylglycerol and glycerophospholipids. High expression of AGPAT2 mRNA in adipose tissue compared to other isoforms suggests that the mutations might affect the adipose tissue the most. The function of BSCL2 remains unknown. Several CGL pedigrees reveal no mutation in either of the above genes and are not linked to these loci, suggesting additional genetic loci for CGL. Thus, several distinct mechanisms can lead to extreme lack of adipose tissue in humans and cause CGL.

1-Acylglycerol-3-Phosphate O-Acyltransferase↗
PubMed2004

Malignant rhabdoid tumour of the third ventricle.

A 16-year-old boy presented to the All India Institute of Medical Sciences hospital with signs and symptoms of raised intracranial pressure. A CT scan showed obstructive hydrocephalus from a large posterior third ventricle mass lesion. The patient underwent a subtotal resection of the tumour, followed by radiotherapy. Histological, ultrastructural and immunohistochemical features of the tumour were consistent with primary malignant rhabdoid tumour. The age of presentation and location of the lesion were unusual.

Adolescent↗
PubMed2003

Isolated central canal rupture of spinal dermoid: report of two cases.

We report two cases of lumbar spinal dermoid cysts with asymptomatic rupture and migration of free fat droplets into the central canal. No fatty droplets were seen within the lumbar subarachnoid space. The presence of fat droplets within the central canal is unusual because the central canal is rudimentary in adults. We suggest that hydromyelia secondary to tumour and specific tumour morphology might facilitate the selective rupture of dermoids into the central canal. We recommend a follow up of these patients to detect any possible intracranial migration of fat droplets and resultant complications.

Adult↗
PubMed2003

Effect of specimen size and aspect ratio on the tensile properties of porcine aortic valve tissues.

The measurement of mechanical properties of biological tissues is subject to artifacts such as natural variability and inconsistency in specimen preparation. As a result, data cannot be easily compared across laboratories. To test the effects of variable specimen dimensions, we systematically modified the size and aspect ratio (AR) of porcine aortic valve tissues and measured their stiffness and extensibility. We found that: (i) as the AR of circumferential specimens increased from 1:1 to 5:1, their stiffness increased by 36% (p < 0.001) and their extensibility decreased by 21% (p < 0.001); (ii) as the AR of radial specimens increased from 0.8:1 to 4:1, their stiffness increased by 36% (p < 0.001) and their extensibility decreased by 34% (p < 0.001); (iii) as the size of circumferential specimens was reduced from 128 to 32 mm2 at fixed AR (2:1), their stiffness decreased by 6 (p = 0.05), and their extensibility increased by 17% (p < 0.001); and (iv) as the size of radial specimens was reduced from 72 to 32 mm2 at fixed AR (2:1), their stiffness decreased by 7% (p = 0.03) and their extensibility increased by 16% (p = 0.005). Thus, as specimens of constant length became narrower, they became stiffer and less extensible, and as specimens of fixed aspect ratio became smaller, they became less stiff and more extensible. Statistical models of these trends were predictive and can thus be used to integrate materials test data across different laboratories.

Animals↗
PubMed2003

Cerebrotendinous xanthomatosis: neuroimaging findings in two siblings from an Indian family.

Cerebrotendinous xanthomatosis (CTX) is exceptionally rare in the Indian population. We present and discuss the clinical, radiological and histopathologic findings in 2 siblings with CTX. Both the patients had juvenile cataract, mental retardation and marked cerebellar ataxia. The Achilles tendon swelling was present in only 1 patient (Case 2). MR imaging showed typical bilateral and symmetrical involvement of the dentate nuclei, inferior olives, brainstem and cerebellar hemispheric white matter. Although the diagnosis of CTX was made in the 3rd decade in both our cases, early diagnosis is possible if neuroimaging is done in the early course of the disease.

Adult↗
PubMed2002

Alterations in cytokine regulation in aged epidermis: implications for permeability barrier homeostasis and inflammation. I. IL-1 gene family.

Acute disruption of the cutaneous permeability barrier with either solvents or tape-stripping stimulates a homeostatic metabolic response in the subjacent nucleated layers of the epidermis that results in a rapid restoration of normal permeability barrier function. When the aged epidermal permeability barrier is stressed, it reveals a diminished capacity for recovery, in comparison to young epidermis, analogous to other organs in the aged when stressed. Although the signals that regulate this homeostatic response by the epidermis have not yet been resolved, acute permeability barrier disruption stimulates release of prestored IL-1alpha, and increased production of potentially regulatory cytokines, including IL-1alpha and TNFalpha in the epidermis. In these studies, we addressed the hypothesis that cytokine dysregulation explains the permeability barrier abnormality in aged epidermis, assessing the regulation of IL-1 and TNF signaling in aged vs young mice. To determine whether the IL-1 family of cytokines plays a key role in the permeability barrier abnormality of the aged, permeability barrier recovery rates were compared in transgenic mice lacking the functional IL-1 type 1 receptor vs wild-type mice at various ages. Knockout of the IL-1 type 1 receptor exacerbates the defect in permeability barrier homeostasis that is seen in age-matched, wild-type counterparts. Furthermore, the sluggish permeability barrier recovery in aged epidermis is associated with, and at least in part attributable to, altered expression of the IL-1 family of cytokines and receptors both under basal conditions and after acute barrier perturbations. Whereas modulations in cytokine expression with epidermal permeability barrier perturbation are qualitatively similar in aged epidermis, they greatly differ quantitatively. In contrast, examination of TNFalpha mRNA and protein basally, and following barrier perturbation revealed no alterations in aged epidermis. Together, these results show that selective alterations in the IL-1 family of cytokines occur with aging and that defects in IL-1 signaling may contribute to the epidermal permeability barrier abnormality of aged skin.

Animals↗
PubMed2002

Nuclear transcription factor-kappaB as a target for cancer drug development.

Nuclear factor kappa B (NF-kappaB) is a family of inducible transcription factors found virtually ubiquitously in all cells. Since its discovery by Sen and Baltimore in 1986, much has been discovered about its mechanisms of activation, its target genes, and its function in a variety of human diseases including those related to inflammation, asthma, atherosclerosis, AIDS, septic shock, arthritis, and cancer. Due to its role in a wide variety of diseases, NF-kappaB has become one of the major targets for drug development. Here, we review our current knowledge of NF-kappaB, the possible mechanisms of its activation, its potential role in cancer, and various strategies being employed to target the NF-kappaB signaling pathway for cancer drug development.

Antineoplastic Agents↗
PubMed2002

Tuberous sclerosis: a presentation of less-commonly encountered stigmata.

The protean manifestations of the tuberous sclerosis complex have lent this condition to extensive review in textbooks and in the medical literature. This condition generally presents by virtue of its neurological manifestations. Osseous stigmata, when encountered, are generally asymptomatic and do not require specific treatment owing to their benignity. We present the case of a young man with a slowly enlarging facial swelling for whom cosmetic surgery was considered. The swelling, present since childhood, had in time assumed disfiguring proportions. In what was hitherto considered an isolated facial deformity, a skull radiograph followed by CT revealed neurological stigmata of tuberous sclerosis. A large cerebellar hamartoma, proliferative soft tissue in the scalp adjacent to focal hyperostosis of the calvarium and the accompanying hemifacial changes seen in this patient constitute less commonly described features of tuberous sclerosis.

Adult↗
PubMed2002

Post-mortem findings in familial partial lipodystrophy, Dunnigan variety.

AIMS: Familial partial lipodystrophy, Dunnigan variety (FPLD), is an autosomal dominant disorder due to missense mutations in the lamin A/C gene and is characterized by gradual loss of subcutaneous fat from the extremities and trunk, fat accumulation in the head, neck and intra-abdominal areas, insulin resistance and its metabolic complications. We studied autopsy findings in two patients with FPLD to determine fat distribution and organ involvement. RESULTS: Patient 1, a 66-year-old woman with the R482Q mutation, had diabetes mellitus, dyslipidaemia, and coronary artery disease and died suddenly. Autopsy confirmed the typical body fat distribution and further revealed excess fat deposition in the subpectoral regions extending to the axillae, in the axillary lymph nodes and in the retroperitoneum. Atherosclerotic vascular disease including old infarcts of the myocardium, temporal lobe and kidneys were noted. Severe amyloidosis of the pancreatic islets and grouped muscle atrophy of the quadriceps and diaphragmatic muscles were present. Patient 2, a 29-year-old woman belonging to a pedigree with the R62G mutation, died of hyperlipidaemia-induced acute pancreatitis. Autopsy of patient 2 revealed extensive pancreatitis, hepatic steatosis and polycystic ovaries. CONCLUSIONS: Our study confirms typical body fat distribution and describes new sites of excess fat deposition. Our data show predisposition to atherosclerosis and polycystic ovaries and suggest that pancreatic amyloidosis may underlie development of hyperglycaemia in FPLD patients.

Adipose Tissue↗
PubMed2001

Multifocal musculoskeletal tuberculosis in children: appearances on computed tomography.

PURPOSE AND PATIENTS: The incidence of skeletal tuberculosis (TB), which once accounted for a majority of cases of extrapulmonary tuberculosis, has fallen significantly in recent years with the advent of effective drug therapy. Disseminated bone involvement in TB is very uncommon but it may still occur in countries where TB is endemic. We present the imaging findings of four children ranging in age from 2 to13 years, each of whom had multiple osseous stigmata of tuberculous infection. They presented to us over a period of 9 months. RESULTS AND CONCLUSION: Three of four children had calvarial lesions, with involvement of the bony orbit in one, and large abscesses were present in the chest wall and the mediastinum of another. Lesions along the dorsal spine were demonstrated in three cases, two of which showed epidural extensions. Bone lesions in the thoracic cage accompanying those in the spine were also seen in two children, one of whom had a solitary destructive focus in a rib distant from the site of vertebral involvement. Bone lesions involving the first metacarpal in one case and the scapular wing in two others are also described. The diagnosis in each of the cases was confirmed by the identification of epitheloid giant cells and caseous necrosis or tubercle bacilli in fine needle aspirates or on tissue culture studies.

Adolescent↗
PubMed2001

Syntheses and structural and electrochemical characterizations of vanadatricarbadecaboranyl analogues of vanadocene and the structural characterization of the [Li(CH(3)CN)2+](6-CH(3)-nido-5,6,9-C(3)B(7)H(9-) tricarbadecaboranyl anion.

A single-crystal X-ray determination of the [Li(CH(3)CN)(2)(+)](6-CH(3)-nido-5,6,9-C(3)B(7)H(9)(-)) salt has shown that the 6-CH(3)-nido-5,6,9-C(3)B(7)H(9)(-) tricarbadecaboranyl anion has a nido-cage geometry based on an octadecahedron missing the unique six-coordinate vertex. The resulting six-membered open face is puckered, with two of the cage carbons (C6 and C9) occupying the low-coordinate cage positions above the plane of the four remaining atoms (C5, B7, B8, and B10). The Li(+) ion is centered over the open face and is solvated by two acetonitrile molecules. The reactions of the 6-CH(3)-nido-5,6,9-C(3)B(7)H(9)(-) anion with various vanadium halide salts, including VCl(4), VCl(3), and VBr(2), each resulted in the isolation of the same five paramagnetic products (2-6) of composition V(CH(3)-C(3)B(7)H(9))(2). X-ray crystallographic determinations of 2-5 showed that the complexes consist of two octadecahedral VC(3)B(7) fragments sharing a common vanadium vertex and established their structures as commo-V-(1-V-4'-CH(3)-2',3',4'-C(3)B(7)H(9))(1-V-2-CH(3)-2,3,4-C(3)B(7)H(9)) (2), commo-V-(1-V-5'-CH(3)-2',3',5'-C(3)B(7)H(9))(1-V-4-CH(3)-2,3,4-C(3)B(7)H(9)) (3), commo-V-(1-V-5'-CH(3)-2',3',5'-C(3)B(7)H(9))(1-V-2-CH(3)-2,3,4-C(3)B(7)H(9)) (4), and commo-V-(1-V-2-CH(3)-2,3,4-C(3)B(7)H(9))(2) (5). These complexes can be considered as tricarbadecaboranyl analogues of vanadocene, (eta(5)-C(5)H(5))(2)V. However, unlike vanadocene, these complexes are air- and moisture-stable and have only one unpaired electron. The five complexes differ with respect to one another in that they either (1) contain different enantiomeric forms of the CH(3)-C(3)B(7)H(9) cages, (2) have a different twist orientation of the two cages, or (3) have the methyl group of the CH(3)-C(3)B(7)H(9) cage located in either the 2 or 4 position of the cage. Subsequent attempts to oxidize the compounds with reagents such as Br(2) and Ag(+) were unsuccessful, illustrating the ability of the tricarbadecaboranyl anion to stabilize metals in low oxidation states. Consistent with this, both the electrochemical oxidation and the reduction of 2 were much more positive than those of the same oxidation state changes in vanadocene. The one-electron reduction of 2 is a remarkable 2.9 V positive of that of Cp(2)V.

Journal Article↗
PubMed2001

Psychological stress perturbs epidermal permeability barrier homeostasis: implications for the pathogenesis of stress-associated skin disorders.

BACKGROUND: A large number of skin diseases, including atopic dermatitis and psoriasis, appear to be precipitated or exacerbated by psychological stress. Nevertheless, the specific pathogenic role of psychological stress remains unknown. In 3 different murine models of psychological stress, it was recently shown that psychological stress negatively impacts cutaneous permeability barrier function and that coadministration of tranquilizers blocks this stress-induced deterioration in barrier function. OBJECTIVES AND METHODS: The relationship between psychological stress and epidermal permeability barrier function was investigated in 27 medical, dental, and pharmacy students without coexistent skin disease. Their psychological state was assessed with 2 well-validated measures: the Perceived Stress Scale and the Profile of Mood States. Barrier function was assessed simultaneously with the stress measures at periods of presumed higher stress (during final examinations) and at 2 assumed, lower stress occasions (after return from winter vacation [approximately 4 weeks before final examinations] and during spring vacation [approximately 4 weeks after final examinations]). RESULTS: The subjects as a group demonstrated a decline in permeability barrier recovery kinetics after barrier disruption by cellophane tape stripping, in parallel with an increase in perceived psychological stress during the higher vs the initial lower stress occasions. During the follow-up, presumed lower stress period, the subjects again displayed lower perceived psychological stress scores and improved permeability barrier recovery kinetics, comparable to those during the initial lower stress period. Moreover, the greatest deterioration in barrier function occurred in those subjects who demonstrated the largest increases in perceived psychological stress. CONCLUSION: These studies provide the first link between psychological status and cutaneous function in humans and suggest a new pathophysiological paradigm, ie, stress-induced derangements in epidermal function as precipitators of inflammatory dermatoses.

Adult↗
PubMed2001

Adolescent occupational toxic exposures: a national study.

BACKGROUND: While many previous studies describe workplace-associated injuries in adolescents, few focus on toxic exposures. Such incidents are unlikely to be reported to either federal or state agencies. However, poison control centers often get called about these poisonings and might serve as a resource for monitoring their occurrence. OBJECTIVE: To describe the frequency and severity of job-related toxic exposures involving adolescents, the specific toxic agents involved, and trends over time. METHODS: Occupational toxic exposures occurring in the United States between 1993 and 1997 were analyzed using the Toxic Exposure Surveillance System database compiled by the American Association of Poison Control Centers. Contingency tables with the chi(2) statistic were used to test bivariate associations. Logistic regression was performed to investigate trends over time. RESULTS: Of 301 228 workplace toxic exposures reported over 5 years, 8779 (3%) involved adolescents younger than 18 years. The most common agents involved were alkaline corrosives (13.2%), gases and fumes (12.0%), cleaning agents (9.7%), bleaches (8.3%), drugs (7.4%), acids (7.2%), and hydrocarbons (6.9%). The injuries were rated as severe in 14.2% of exposures, life-threatening in 0.3%, and there were 2 deaths. The proportionate frequency of occupational exposures occurring among adolescents vs adults increased over time (odds ratio, 1.003; P<.001). CONCLUSIONS: Adolescent occupational toxic exposures are an underrecognized hazard in the United States. Poison control center experience can be used to fill a gap in the surveillance of such injuries.

Adolescent↗