Biomedical subjects

V Jayaraman

Publications and source records attributed to V Jayaraman.

30 records · Page 2Linked to original sources

PubMed1995

Structure of a third cooperativity state of hemoglobin: ultraviolet resonance Raman spectroscopy of cyanomethemoglobin ligation microstates.

Ultraviolet resonance Raman (UVRR) spectra have been obtained for cyanometHb (Hb = hemoglobin) hybrid tetramers representing several ligation microstates, using dimer interchange techniques and spectral subtraction. Relative to fully ligated tetramers, Hb(CN)4, the monoligated hybrids and deoxyHb all show fully developed T/R difference UVRR bands which are associated with T state quaternary contacts across the alpha 1 beta 2 interface, involving the Trp beta 37 and Tyr alpha 42 residues. Triligated species show quite different signals, arising from the interior residues Trp alpha 14 and/or beta 15. From earlier studies, these Rdeoxy signals are attributed to E helix displacement toward the heme in deoxy subunits within R state tetramers, resulting in weakened Trp H-bonds. Asymmetric diligated hybrids, containing both ligands in the same dimer unit, show signals characteristic of the T quaternary contacts, but they are attenuated by 40%. An equilibrium mixture of T and R state molecules is ruled out by the absence of significantly strong Rdeoxy difference bands. Rather, the spectral attenuation is attributed to weakening of the T state contacts at the alpha 1 beta 2 interface. This interpretation is supported by previous observations that the mutational pattern of free energy perturbations for the asymmetric hybrid is T-like and not that of a T/R equilibrium or an R-like state. The asymmetric hybrid represents a third cooperativity state, T', having a T quaternary arrangement of the subunits but a deformed alpha 1 beta 2 interface, with weakened contacts.

Hemoglobins↗

PubMed1993

R and T states of fluoromethemoglobin probed by ultraviolet resonance Raman spectroscopy.

Ultraviolet resonance Raman spectra are reported for the fluoride complex of methemoglobin (metHbF), with and without added inositol hexaphosphate (IHP), an allosteric effector known to stabilize the T quaternary structure. Environmental changes in Trp and Tyr residues give rise to the difference features, which are similar to those observed in the difference spectrum between deoxyHb and the CO adduct, consistent with T-state formation in metHbF in the presence of IHP. There are, however, important differences. The intensities of the difference signals are attenuated by about one-third, indicating a lower T-state population in the IHP-bound metHbF than in native deoxyHb. And a new signal is seen which arises from the interior tryptophans, probably reflecting a change in their H-bond status associated with the presence of fluoride as the sixth heme ligand in the T state. Implications of these results for the nature of the molecular forces opposing ligation in the T state are discussed.

Hemoglobins↗

PubMed1993

Burns in Madras, India: an analysis of 1368 patients in 1 year.

Analyses were made of 1368 patients who attended Kilpauk Medical College Hospital, Madras with burns between 1 May 1987 and 30 April 1988. Nine hundred and sixty-five patients were admitted, of whom 505 died. The peak age incidence was in young adults (11-30 years; 58.9 per cent of all burns). Three quarters of the patients came from the low family income group, 39.5 per cent were illiterate and 86.2 per cent of burns occurred in the home. Of those admitted 81 per cent of the injuries were flame burns; in 31.3 per cent the burn affected more than half of the body surface. Of the 505 deaths 94.8 per cent were the result of flame burns (at least 323 being caused by kerosene), and 20.4 per cent were suicide. Most of the deaths (91 per cent) occurred in the first 5 days. The urgent need for burn prevention in the Madras area is discussed.

Adolescent↗

PubMed1991

Electrical burns treated in an Indian hospital.

A 17-year survey of all electrical burns admitted to the Department of Plastic and Reconstructive Surgery at the Kilpauk Medical College Hospital, Madras between 1973 and 1990 has been made. A total of 8040 cases of burns were treated in this Department and in this group 923 were pure electrical burns. The majority of electrical burns occurred in the age group 20-40 years. Some of the clinical features of our electrical burns resembled closely those of a crush injury. Most of the patients required primary reconstruction and this was delayed when the viability of tissues was in doubt. Human error was responsible for the injury in 68 per cent of patients and all the 64 patients who were below the age of 10 years belonged to this group.

Adolescent↗

PubMed1988

Deepithelialized turnover flaps in burns.

Acute and chronic burns leave behind a full-thickness defect that always requires a flap cover. Such defects are common in electrical burn injuries of the limbs. This paper deals with 35 patients with full-thickness defects following burns in whom deepithelialized turnover dermis flaps and deepithelialized turnover flaps with deep fascia have been used. This flap is an extension of Hynes's reversed dermis graft and Smahel's deepithelialized turnover flap where there is a larger area of blood supply on the deeper aspect of the dermis. If a good hinge is provided for safe blood supply, such a flap settles well in the defect, and cumbersome multistaged procedures can be avoided. If there is less fatty tissue in the area of flap used, then reversed dermis flaps are ideal because split-skin graft take is good. When there is a lot of fatty tissue on the undersurface of dermis, the fascia is also included to make it a reversed fasciocutaneous flap to augment the blood supply and for better split-skin graft survival. Advantages of the procedure and complications are elaborated.

Arm Injuries↗

PubMed1988

Denervated palmaris longus tendon as a skeletal muscle transplant in circumferential pharyngoplasty.

The incidence of velopharyngeal incompetence (VPI) following cleft palate surgery is fairly high in our country. We have attempted to analyse the aetiology and then selected 50 cases of VPI from our group of operated cleft palates. These patients were then evaluated using cephalometry, speech rating, pressure studies and nasendoscopy. We identified 13 patients in whom there was incompetence due to failure of movement of the walls responsible for proper closure of the velopharyngeal port. In these patients we performed circumferential sling pharyngoplasty using denervated palmaris longus; since this procedure narrowed the port circumferentially. We re-evaluated these patients and the results have been gratifying. Speech rating improved and E.M.G. tracings after 6 months showed evidence of reinnervation of the Palmaris Longus.

Cephalometry↗

PubMed1986

The management of anaerobic infection in extensive burns.

A survey of 300 patients with burns covering more than 30 per cent of the body surface area indicated that 33 patients had proven wound infection with anaerobic bacteria and 11 patients showed positive blood cultures. Although metronidazole was the anti-bacterial agent of choice for treating these 33 patients, treatment was not always successful since 7 patients died. The most common sites of infection were the perineum and upper parts of the legs.

Adolescent↗

PubMed1985

Incidence of burn wound sepsis in 600 burned patients treated in a developing country.

Infection is the most important problem in the treatment of burns in a developing country. A burn compromises a major body protective mechanism, namely the skin. Hence, the susceptibility to local infection increases at these sites. The incidence of burn wound sepsis is very high in south India as the socio-economic conditions and the standard of personal hygiene are poor and the hot moist climatic conditions encourage bacterial growth. These three factors are rarely present in the temperate zone countries of Europe and North America. This study was undertaken to identify more clearly the factors that are responsible for the higher incidence of burn wound infection and to formulate methods of treatment which are appropriate for our patient population living in a tropical country.

Adolescent↗

PubMedDate not supplied

Serum enzymatic changes modulated using trypsin: chymotrypsin preparation during burn wounds in humans.

The levels of marker enzymes for liver function, namely transaminases (SGPT, SGOT), creatine phosphokinase (CPK), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) were estimated in the sera of burn patients by administering trypsin: chymotrypsin preparation and comparing with an untreated group. Neutrophil proteolytic activity was also measured by assaying the lysosomal enzymes, namely neutrophil elastase and cathepsin D. Our earlier studies have already proved the efficacy of the above enzyme preparation to burn patients on the enhancement of vascular responses during the acute phase of the burn injury. These beneficial responses were brought about by the modulation of acute phase proteins expressed in the liver. Hence, it is of interest to study the changes in the above mentioned liver enzymes and certain lysosomal enzymes in the serum during the first 10 days of burn injury. The levels of liver and lysosomal enzymes markedly decreased in the treated group when compared with the untreated group. The enzyme studies clearly indicated that the initial rise in the liver enzymes was minimized in the treated group when compared with the untreated group and this helped in reducing the stress to the liver in the treated cases. The increase in the activity of alpha 1-antitrypsin and alpha 2-macroglobulin and decreased levels of C-reactive protein are attributed to the reduction of proteolytic enzyme levels in the treated group and minimizing the degradative changes during wound repair.

Administration, Oral↗

PubMedDate not supplied

Paediatric rehabilitation in a developing country--India in relation to aetiology, consequences and outcome in a group of 459 burnt children.

Age, aetiology of burn, percentage body surface area burnt and post-burn sequelae have a direct relationship to the rehabilitative necessity in burnt children in a developing country--India. In spite of the gross disfigurements and sequelae, only adolescent children required psychosocial rehabilitation. These are the results following a retrospective analysis of 459 paediatric burn patients in Madras, India.

Adolescent↗

PubMedDate not supplied

Ultrasound-assisted fabrication of nanoporous CdS films.

A new method for fabricating nanoporous CdS films is reported. It involves exposing the CdS solution with ultrasound waves during the process of dip coating. Indium tin oxide (ITO)-coated glass and plastic (commercial transparency) were used as substrates. In each case three different precursors were used for dip coating. The precursors used were CdCl2 and thiourea in one case and CdS nanoparticles prepared by sonochemical and microwave-assisted methods in the other two cases. X-ray diffraction studies performed on these powders show a phase corresponding to cubic CdS. The Field Emission Scanning Electron Microscopy (FE-SEM) images of the films on plastic showed uniform pores with a diameter of 80 nm for all three methods. Optical absorption measurements indicated a blue shift and multiple peaks in the absorption curve. The FE-SEM observations of the films on an ITO/glass substrate indicated a crystalline film with voids. The UV-vis absorption results indicated a blue shift in the absorption with an absorption edge at 435, 380, and 365 nm for CdS films made by solution growth, sonochemical, and microwave routes, respectively. The magnitude of the absorption is dependent on film thickness, and the observed blue shift in the absorption can be explained on the basis of quantum confinement effects.

Adsorption↗

PubMedDate not supplied

Vegetative tissue lectins of peanut (A. hypogaea).

Lectin activities in roots, nodules, stems and leaves of 1-6 week old peanut plant (A. hypogaea) were checked by erythrocyte (human and rabbit) agglutination and sugar inhibition assays. Human and rabbit erythrocyte agglutinating activities were specifically inhibited by lactose/cellobiose (SLII) and methyl alpha-mannoside (SLI) respectively. Seeds, embryos and cotyledons agglutinated neuraminidase treated human erythrocytes and that activity was inhibited by T-disaccharide. In the roots of field grown plants SLI was the major activity, while nodules showed both activities (SLI and SLII). Specific activities of SLI and SLII were maximal in stem tissue and hypocotyl exhibited minimal levels. Actively growing tissues like newly emerging young leaves and elongating stem contained more SLII activity in comparison to the mature tissues. Immunological test indicated that all the vegetative tissue lectins are serologically related.

Animals↗