Biomedical subjects
Publications and source records attributed to V Nanda.
Rhinophyma is the advanced stage of acne rosacea and a source of embarrassment for the patient. Secondary localized cutaneous amyloidosis complicating rhinophyma is not reported in the literature. A patient with rhinophyma was treated by excision and primary closure. The histologic examination showed amyloidosis.
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The single tryptophan at position 121 of human interleukin-2 (IL-2) can form an NH-pi hydrogen bond with Phe 117 involving the indole nitrogen and the benzene aromatic ring. At pH 5.5, this type of aromatic interaction results in a fluorescence quantum yield three-fold lower than that of a fully solvent exposed tryptophan. At pH 2.1, IL-2 forms a compact denatured state with twice the emission intensity of the native protein. Global analysis of time-resolved fluorescence emission at multiple emission wavelengths shows that native and acid-denatured IL-2 can be described by four decay components. The fractional amplitudes of the shortest sub-nanosecond lifetimes are higher in the native state, suggesting rapid quenching due to the NH-pi hydrogen bond. In the denatured state, longer lifetimes have greater fractional amplitudes, indicating a smaller population of hydrogen-bonded species. Electrostatic-dipolar relaxation of the tryptophan microenvironment upon excitation is greater in the native-state of IL-2 than the acid-denatured state. This suggests that acid-denaturation sequesters Trp 121 from polar residues, while maintaining an interaction with Phe 117. This is consistent with the model of secondary structure preservation and hydrophobic clustering in molten-globule intermediates.
Trp 48, a conserved, buried residue commonly found in the hydrophobic core of homeodomains, has an unusually low fluorescence quantum yield. Chemical denaturation of Drosophila homeodomains Engrailed and Antennapedia(C39S) result in a four-fold increase in quantum yield, while unfolding of Ultrabithorax causes a twenty-fold enhancement. Global analysis of time-resolved fluorescence decay monitored at multiple emission wavelengths reveals sub-nanosecond lifetime components which dominate the overall intensity. Based on structure and sequence analysis of several homeodomains, we deduce that quenching is due to a transient, excited-state NH ellipsis pi hydrogen bond involving Trp 48 and a conserved aromatic residue at position 8. Additionally, both time-resolved fluorescence of indole-benzene mixtures and an electrostatic model of the proposed tryptophan-aromatic interaction substantiate different aspects of this mechanism. A survey of the Protein Data Bank reveals many proteins with tryptophan-aromatic pairs where the indole nitrogen participates in a NH ellipsis pi hydrogen bond with the ring of another aromatic residue. Chemical denaturation of one protein found in this survey, human fibronectin type III module 10, causes an enhancement of the fluorescence quantum yield. This unique interaction has implications for many other systems and may be useful for studying larger, multi-tryptophan containing proteins.
We used a free vascularized small periosteal bone graft to treat scaphoid nonunion. The graft consisted of periosteum, full-thickness cortex, and the underlying cancellous bone and was harvested from the supracondylar region of the femur. The graft was nourished by the articular branch of the descending geniculate artery and vein. Unlike the currently used vascularized bone grafts, this graft can be easily harvested and shaped to accommodate the bone defect of the scaphoid without disturbing its vascularity and can then be transferred with microvascular anastomosis of the nutrient vessels to the radial artery and its venae commitantes. Ten patients with longstanding nonunion of the scaphoid secondary to avascular necrosis, confirmed by radiologic and intraoperative findings, were treated with this vascularized bone graft. Union was achieved in all 10 patients at an average of 12 weeks after surgery. The average follow-up period for all fractures was 3.5 years. The scores for overall outcome, according to the Mayo wrist scoring system, were excellent in 4 patients, good in 4, and fair in 2. Two unsatisfied patients had preoperative signs of early periscaphoid osteoarthrosis. This free vascularized small bone graft from the supracondylar region of the femur is an attractive alternative to the conventional vascularized bone grafting procedures.
BACKGROUND: Recent interest in reconstruction of the upper limb following brachial plexus injuries has focused on the restoration of prehension following complete avulsion of the brachial plexus. METHODS: Double free muscle transfer was performed in patients who had complete avulsion of the brachial plexus. After initial exploration of the brachial plexus and (if possible) repair of the fifth cervical nerve root, the first free muscle, used to restore elbow flexion and finger extension, is transferred and reinnervated by the spinal accessory nerve. The second free muscle, transferred to restore finger flexion, is reinnervated by the fifth and sixth intercostal nerves. The motor branch of the triceps brachii is reinnervated by the third and fourth intercostal nerves to restore elbow extension. Hand sensibility is restored by suturing of the sensory rami of the intercostal nerves to the median nerve or the ulnar nerve component of the medial cord. Secondary reconstructive procedures, such as arthrodesis of the carpometacarpal joint of the thumb, shoulder arthrodesis, and tenolysis of the transferred muscle and the distal tendons, may be required to improve the functional outcome. RESULTS: The early results were evaluated in thirty-two patients who had had reconstruction with use of the double free muscle procedure. Twenty-six of these patients were followed for at least twenty-four months (mean duration, thirty-nine months) after the second free muscle transfer, and they were assessed with regard to the long-term outcome as well. Satisfactory (excellent or good) elbow flexion was restored in twenty-five (96 percent) of the twenty-six patients and satisfactory prehension (more than 30 degrees of total active motion of the fingers), in seventeen (65 percent). Fourteen patients (54 percent) could position the hand in space, negating simultaneous flexion of the elbow, while moving the fingers at least 30 degrees and could use the reconstructed hand for activities requiring the use of two hands, such as holding a bottle while opening a cap and lifting a heavy object. The results were analyzed to identify factors affecting the outcome. CONCLUSIONS: The double free muscle procedure can provide reliable and useful prehensile function for patients with complete avulsion of the brachial plexus.
Thromboangiitis obliterans (TAO), also known as Buerger's disease, is an important cause in India of chronic arterial occlusion of the limbs. The current modalities of therapy do not provide adequate relief to a large number of these patients. An omentum autotransplantation to the lower limbs was performed in three patients as a limb salvage procedure. The initial results with up to a year of follow-up are so far encouraging.
Long strictures of the bulbomembranous urethra are a challenge of modern urology, with no absolutely reliable technique for a favorable outcome. The authors describe a technique of urethroplasty using the radial forearm free flap, in a patient suffering from posttraumatic stricture, with excellent results.
Leukocyte adhesion deficiency is a rare autosomal recessive disorder caused by the absent or severely reduced cell surface expression of a subfamily of leukocyte integrin molecular (beta 2 leukocyte integrins, CD11a/CD18, CD11b/CD18, CD11c/CD18). These molecules are required for the normal processes of leukocyte adherence and chemotaxis. Patients often die during the first years of life of a severe bacterial or fungal infection. We describe a 13-year-old boy with leukocyte adhesion deficiency who had intermittent cutaneous infections that were recalcitrant to treatment. Except for periodontitis, he had no other clinical problems. The diagnosis of leukocyte adhesion deficiency should be considered in patients with recurrent cutaneous infections that do not respond well to therapy, even in the absence of more serious manifestations. Evaluation should include flow cytometry studies to detect surface expression of the beta 2 leukocyte integrins on both resting and activated polymorphonuclear leukocytes.
We describe the long-term follow-up of two patients who experienced diffuse fasciitis and eosinophilia while ingesting L-tryptophan for treatment of insomnia. This is one of the first reports in the dermatologic literature of the long-term follow-up of eosinophilic fasciitis in association with L-tryptophan ingestion. Both patients fit the Centers for Disease Control's criteria for eosinophilia-myalgia syndrome. The literature on the eosinophilia-myalgia syndrome is reviewed.
Ten patients with tropical sprue (TS) and 10 with irritable bowel syndrome (IBS) as controls were studied to characterize the immunocytes in the jejunal mucosa. IgA cells numbered 516,155 +/- 48,715 cells/mm3 in TS and 729,308 +/- 146,011/mm3 in the IBS patients. IgG cell counts were 28,885 +/- 8,081/mm3 in TS and 10,615 +/- 4,100/mm3 in IBS; IgM counts were 170,729 +/- 25,015/mm3 in TS and 169,253 +/- 45,353/mm3 in IBS. A positive correlation was present between IgM-bearing plasma cells and corresponding serum immunoglobulins (r = +0.71; p less than 0.05). No correlation was evident between the different immunocytes (IgA, IgG, and IgM) and the duration of illness, serum albumin, and tests for absorption of fat, B-12, and D-xylose (p greater than 0.05). The gut immunocytes expressed in absolute numbers were higher in our controls and TS patients than reported in Western populations.
Serologic markers for HBV, HDV, HIV-1 and HTLV-1 were tested in 42 patients with a primary hepatocellular carcinoma (PHC); 19 with a malignancy of epithelial origin (EPM) and 16 with a non-epithelial malignancy (NEPM) in the Gizan Area of Saudi Arabia. HBV exposure in 77 PHC, EPM and NEPM patients was 92.2 per cent for any marker (overall) while 75.3 per cent positive for HBsAg. 3.9 per cent positive for anti-HBc and 12.9 per cent positive for anti-HBs. There was no inter PHC, EPM, NEPM or intersex variation for an individual marker or total HBV exposure. Among HBsAg-positives, 9 of the 12 PHC tested, 7 of the 10 EPM, 1 of the 9 NEPM were anti-D IgG positive. The HDV prevalence was the lowest in NEPM (p < 0.01). In patients with a malignancy, all HBV and HDV markers were higher than those of control population, even though anti-HBs was lower (p < 0.001). The probable contribution through different viruses in pathogenesis of malignancies of different types should be ascertained through polymerase chain reaction for viral components, oncogenes, etc. on tumourous biopsy tissues. The aggravation in PHC morbidity in HBV hyperendemic foci through HIV infection should be monitored through tests for unintegrated and integrated viral DNA in tumorous and non-tumorous tissues.
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A patient with poisoning due to formaldehyde ingestion is described. Endoscopy showed severe oesophageal burns and moderate gastric injury. Four weeks later endoscopy and barium examination revealed a normal oesophagus while the distal part of stomach was cicatrized.
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