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Biomedical subjects

R Deshmukh

Publications and source records attributed to R Deshmukh.

11 recordsLinked to original sources
PubMed2003

Group-delay ripple correction in chirped fiber Bragg gratings.

Group-delay ripple (GDR) introduced by systematic and random errors in chirped fiber Bragg grating fabrication is the most significant impediment to application of these devices in optical communication systems. We suggest and demonstrate a novel iterative procedure for GDR correction by subsequent UV exposure by use of a simple solution of the inverse problem for the coupled-wave equation. Our method is partly based but does not fully rely on the accuracy of this solution. In the experiment we achieved substantial reduction of the low-frequency group-delay ripple, from +/- 15 to +/- 2 ps, which resulted in dramatic improvement of the optical signal-to-noise-ratio system penalty, from 7 to less than 1 dB, for a chirped fiber Bragg grating used as a dispersion compensator in a 40-Gbit/s carrier-suppressed return-to-zero system.

Journal Article↗
PubMed2001

Homologues of neisserial heme oxygenase in gram-negative bacteria: degradation of heme by the product of the pigA gene of Pseudomonas aeruginosa.

The oxidative cleavage of heme to release iron is a mechanism by which some bacterial pathogens can utilize heme as an iron source. The pigA gene of Pseudomonas aeruginosa is shown to encode a heme oxygenase protein, which was identified in the genome sequence by its significant homology (37%) with HemO of Neisseria meningitidis. When the gene encoding the neisserial heme oxygenase, hemO, was replaced with pigA, we demonstrated that pigA could functionally replace hemO and allow for heme utilization by neisseriae. Furthermore, when pigA was disrupted by cassette mutagenesis in P. aeruginosa, heme utilization was defective in iron-poor media supplemented with heme. This defect could be restored both by the addition of exogenous FeSO4, indicating that the mutant did not have a defect in iron metabolism, and by in trans complementation with pigA from a plasmid with an inducible promoter. The PigA protein was purified by ion-exchange chromotography. The UV-visible spectrum of PigA reconstituted with heme showed characteristics previously reported for other bacterial and mammalian heme oxygenases. The heme-PigA complex could be converted to ferric biliverdin in the presence of ascorbate, demonstrating the need for an exogenous reductant. Acidification and high-performance liquid chromatography analysis of the ascorbate reduction products identified a major product of biliverdin IX-beta. This differs from the previously characterized heme oxygenases in which biliverdin IX-alpha is the typical product. We conclude that PigA is a heme oxygenase and may represent a class of these enzymes with novel regiospecificity.

Amino Acid Sequence↗
PubMed1996

Profile and characteristics of animals bites in India.

Animal bites and so also the incidence of rabies in India are on rise. There are regional differences in the animal responsible for the bite. Different practices including use of traditional remedies are prevalent for wound treatment. In India this report analyses the profile and characteristics of animal bites in 869 patients from various regions. Apart from dog and cat, other animals such as cow, monkey, horse, pigs, camel were responsible for bite and could be possible vectors in transmission of rabies. Traditional remedies such as application of chilly paste is still practiced in state of Rajasthan.

Adolescent↗
PubMed1995

Prediction of amputation wound healing with skin perfusion pressure.

PURPOSE: The purpose of this study was to determine whether laser Doppler skin perfusion pressure (LD-SPP) could accurately predict amputation wound healing. METHODS: We studied a total of 62 limbs in 52 patients (28 men and 24 women) with a mean age of 62.2 years (range 34 to 93 years). From this, 39 limbs underwent major amputation (15 above-the-knee, 24 below-the-knee), and 23 limbs underwent minor amputations (4 transmetatarsal and 19 toes). There were five postoperative deaths, leaving a total of 57 limbs available for analysis. RESULTS: Three of 13 above-knee amputations failed to heal. Twenty-one of 23 below-knee amputations healed. Three of four transmetatarsal amputations failed to heal and eight of 17 toe amputations failed to heal. Binary table analysis showed that an LD-SPP value of 30 mm Hg or greater had a negative predictive value (healing occurred) of 90%. An LD-SPP value of less than 30 mm Hg at the amputation site had a positive predictive value (healing failure) of 75%, (p < 0.001, chi square analysis). For major amputations, negative predictive value was 100%, and positive predictive value was 83%, (p < 0.001). For minor amputations, negative predictive value was 75% and positive predictive value was 66.7%, (p < 0.09). CONCLUSION: These data support the use of the LD-SPP test in the selection of major amputation level consistent with healing in ischemic limbs. Further study of the value of this parameter in the determination of minor amputation wound healing is necessary.

Adult↗
PubMed1993

Acute obstructive uropathy secondary to pelvic hematoma compressing the bladder: report of two cases.

Two patients with traumatic retroperitoneal hematomas causing obstructive uropathy required surgical evacuation of the hematoma to relieve the obstruction. Fast recovery of renal function and an instant increase in urine output resulted. The obstruction to the urine outflow by the retroperitoneal hematoma caused near total collapse of the bladder in these patients, which was corrected by angiographic embolization and surgical removal of the hematoma.

Acute Disease↗
PubMed1993

Radical cystectomy for invasive squamous cell bladder cancer in a renal transplant patient.

A rare case of invasive squamous cell carcinoma of the urinary bladder developing 5 years after cadaveric renal transplant is described. The technical precautions to be taken while performing a radical cystectomy in such a situation is highlighted. This patient required chemotherapy in the post-operative period, and the role of chemotherapy in the presence of immunosuppressive therapy is discussed.

Carcinoma, Squamous Cell↗
PubMed1993

Gingival fibromatosis: study of three generations with consanguinity.

Familial gingival fibromatosis affecting six members among three generations of an Islamic family is reported. Clinical findings are reported and the inheritance pattern is discussed. Histopathologic examination of the excised tissue revealed mainly fibroblasts with prominent, rough-surfaced endoplasmic reticulum. Cells with vesicular nuclei, resembling mast cells, were also observed.

Adolescent↗
PubMed1986

ICRC vaccine-induced changes in M. leprae-specific cell-mediated immunity in langur (Presbytis entellus) monkeys.

The effects of the administration of ICRC antileprosy vaccine on skin reactions and lymphocyte transformation tests (LTT) to antigens of Mycobacterium leprae have been investigated in Hanuman langur monkeys (Presbytis entellus) which live native to north India. In a majority of these monkeys, the vaccine brings about lepromin conversion associated with a change in tissue response consistent with "ugrading" of immunity. However, no concomitant changes were observed in the LTT. The significance of these observations is discussed. It is proposed that the langur monkey could be used as a laboratory model to screen "candidate" antileprosy vaccines.

Animals↗
PubMedDate not supplied

[Anatomic rationale for a transmaxillary access to the cavernous sinus].

UNLABELLED: W. Couldwell et al. were the first to propose a transmaxillary access to the cavernous sinus in 1997. The authors showed that this approach was low-invasive and cosmetic and it ensured visualization of different nervous formations of the cavernous sinus and the intracavernous segment of the internal carotid artery. This study was undertaken to study microsurgical anatomy, to simulate a transmaxillary access, to demonstrate its expediency, and to assess the use of endoscopic techniques when this access was applied. The study was conducted in 3 steps: 1) a craniometric study on 33 skulls and 25 craniograms to examine the craniological and geometric parameters of the anatomy of the osseous structures included into the transmaxillary access; 2) simulation of the access on the osseous structures of the skull (2 sides); by including anterior and posterior maxillotomy and bone drilling-out around the round foramen; 3) microsurgical preparation--dissection was performed on 3 head samples (5 sides) at the Laboratory of Microneurosurgical Anatomy, Acad. N. N. Burdenko Research Institute of Neurosurgery, Russian Academy of Medical Sciences. Endoscopy was tested when the transmaxillary access was applied. The results were as follows: 1. The depth of the access failed to correlate with the shape of the skull. The operative observation angle averaged 18-23 degrees. 2. Simulation of the transmaxillary access on the dried skull made it possible to visualize the medial portion of the infratemporal fossa, by enlarging the pterygpid-maxillary fissure. The bone drilling-out boundaries for the skull base were defined. 3. Microsurgical dissection after removal of the posterior maxillary sinus wall and opening the pterygopalatine fossa. The topography of the maxillary artery and nerve was studied. After drilling out the bone of the skull base, the lower wall of the cavernous sinus was crescent. The cavernous sinus was opened as far as possible both above the maxillary nerve and between the second and third branches of the trigeminal nerve. CONCLUSIONS: 1. The access is deep and narrow, yet low-traumatic. 2. It may be the access of choice in removing a small pathological focus in the pterygopalatine fossa, round foramen or lower portions of the cavernous fossa. 3. The access may be used to approach the medial portion of the infratemporal fossa. 4. The described stepwise microsurgical anatomy and internal guiding lines in the retromaxilllary space permit one to perform surgical operations with confidence. 5. With this access, there is no guidance over the great vessel (internal carotid artery). 6. The access passes through the vestibule of the mouth; in this connection its application is undesirable at surgery for intradural abnormalities.

Cavernous Sinus↗