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Biomedical subjects

M Sharma

Publications and source records attributed to M Sharma.

At least 181 records · Page 10Linked to original sources
PubMed1999

Effect of protein and phosphate restricted and calcium and alphacalcidol supplemented diet on renal and parathyroid functions and protein status in chronic renal failure patients.

OBJECTIVE: To assess the effect of low protein (0.6 g/kg/day), low phosphate (5-10 mg/kg/day) diet with calcium (600 mg/day) and alpha-D3 (0.5 microgram/day) supplementation on renal and parathyroid functions in patients with chronic renal failure (CRF). METHODS: The study included 20 adult patients of CRF, maintained on diet therapy alone. The patients were followed up for renal and parathyroid functions and protein status for 6 months at monthly interval. RESULTS: There was symptomatic improvement in 88% patients. Blood urea and serum creatinine decreased significantly (p < 0.001 and < 0.01, respectively) and the slope of inverse serum creatinine against time changed to static or an upslope. Glomerular filtration rate (GFR) improved from a basal value of 29.35 +/- 18.2 ml/min to 39.25 +/- 27 ml/min after 6 months. Serum parathyroid hormone (PTH) level of 197.65 +/- 133.7 pg/ml and post treatment level of 254.55 +/- 217.19 after 6 months were not different (p > 0.05). Serum calcium remained stationary with a slight increase in serum phosphorus. Phosphorus had a negative correlation with calcium and GFR, whereas calcium had a negative correlation with PTH and phosphorus. PTH had a positive correlation with phosphorus and negative with GFR and calcium. CONCLUSION: There was an improvement in renal functions without any deleterious effect on the protein status of the patients of CRF. Also, there was halting of parathyroid dysfunction especially in those patients where there was no evidence of pre-existing hyperparathyroidism. Hence, dietry management should be strictly enforced in CRF patients early in the course of disease.

Adult↗
PubMed1999

Community based study of reproductive tract infections among ever married women of reproductive age in a rural area of Haryana, India.

A community based study was carried out to estimate the load of reproductive tract infections (RTIs) among ever married rural women aged 15-44 years and utilisation of a mobile village based treatment facility by them, during 1997. Complete household survey was done in 10 randomly selected villages of Mahindergarh district in Haryana, India. A total of 2325 women were interviewed by auxiliary nurse midwives and were invited for medical examination in a health camp set-up in their village. Sixty-one percent (1415/2325) women reported symptoms of RTIs. Only 35% (812/2325) had their per-speculum examination done. Out of those examined, 32% (263/812) had vaginitis, 21% (175/812) had cervicits, and 19% (156/812) had pelvic inflammatory disease. Vaginal smear of those having discharge revealed that 48% (231/476) had bacterial vaginosis, 0.8% (4/476) had fungal infection 9% (44/496) had trichomonal infection and none was found to be having gonococcal infection. Tests for chlamydial infection could not be performed as the cost was not affordable. Eighty-nine percent of women who reported symptoms of RTIs had not consulted anyone for their problem prior to our village based camp. Only 42% symptomatic and 24% asymptomatics availed the services even in the village based camps. Study revealed high load of reproductive tract infections and low utilisation of treatment facility. In-depth studies are required to understand for high RTI morbidity load and low treatment seeking rate so as to design an appropriate RTI control programme.

Adolescent↗
PubMed1998

Isolation and analysis of dityrosine from enzyme-catalyzed oxidation of tyrosine and X-irradiated peptide and proteins.

Dityrosine (DT) was isolated in a single-step by reversed-phase HPLC in 25% yield from enzyme-catalyzed oxidation of N-acetyl tyrosine followed by deacetylation. The isolated product was characterized by 1H NMR. A three-step chromatographic procedure was reported to facilitate the preparation of DT from the enzyme-catalyzed oxidation of tyrosine in 26% yield of theoretical maximum. Upon irradiation at 284 nm in acidic and 315 nm alkaline conditions, DT exhibits strong fluorescence at 400 nm-range. However, when excited at 300 nm-range, contribution of similar fluorescence by Trp oxidation and other protein modifications cannot be overruled. In order to identify the formation of DT unequivocally, Tyr was subjected to X-irradiation under nitrogen at pH 4 and labeled with dansyl chloride. HPLC conditions were devised to resolve dansylated DT from dansylated standard amino acids. Radiation-induced DT was identified by cochromatography with a dansylated, authentic sample of DT isolated and characterized from enzyme-catalyzed oxidation of Tyr. The formation of DT in the irradiated samples, determined by the integrated peak area, increased with dose (0-600 Gy). HPLC analysis of dansylated hydrolysate of the major product from an irradiated tripeptide (Tyr Gly Gly) detected Gly and DT (2:0.5). Extension of the model study to irradiated BSA and RNase A also showed DT as the major oxidation product of Tyr under the experimental conditions. Fluorescence signal of dansylated DT was linear from 0.5 pmol to 1.5 nmol (correlation coefficient 0.999, n = 3). The detection limit 0.5 pmol per 5 microliters injection hydrolysate corresponds to one molecule of DT per 300 molecules of BSA (BSA at 1 mg/ml). DT can be used as a marker for assessing oxidative damage of proteins. Most standard amino acid analysis techniques are limited to detect normal residues of proteins. The assay reported in the present study has potential for low-level detection of DT unequivocally and may be useful for monitoring oxidative stress-related physiological and pathological processes.

Chromatography, High Pressure Liquid↗
PubMed1998

Soil Adsorption Coefficients of s-Triazines Estimated with a New Gradient HPLC Method.

A high-performance liquid chromatography (HPLC) method employing gradient elution was developed to predict soil adsorption coefficients (K(oc)) from HPLC capacity factors. The gradient method allows for the determination of K(oc) values over a range of 4.4 orders of magnitude in a single experiment without adjustment of the solvent composition, as is required in isocratic HPLC measurements. The range of K(oc) estimated can easily be extended by using reference compounds with lower or higher log K(oc) values. Therefore, gradient HPLC is an appropriate screening method for K(oc) and was used to investigate s-triazine herbicides and their degradation products. Log K(oc) ranged from 0.8 for cyromazine to a maximum of 2.6 for anilazine and aziprotryne. HPLC-derived K(oc) values of s-triazines containing an azido group were higher than and those of hydroxy-s-triazines were lower than K(oc) values estimated according to the fragment contribution method of Meylan et al. (1992). According to this method, the log K(oc) of the keto form of hydroxy-s-triazines was >1 log unit higher than that of the enol form.

Journal Article↗
PubMed1998

Seasonal affective disorder: report from India (latitude 26 degrees 45'N).

BACKGROUND: A number of studies have established the entity of seasonal affective disorder (SAD) and delineated the presence of atypical depressive features of carbohydrate craving, hyperphagia and hypersomnia. Most literature has emanated from research carried out in temperate climates, and only few reports are available from tropical countries, especially India. METHODS: Consecutive patients with recurrent mood disorder (who had at least 2 episodes of depression in the past) comprised the study sample. The diagnosis of mood disorder was made according to DSM-III-R criteria. The sample was divided into two groups - seasonal and non-seasonal according to the DSM-III-R criteria of seasonal pattern. The depressed patients were rated on SADD and HDRS, and manic patients on BRMRS. RESULTS: Eighteen of 93 patients fulfilled the criteria of seasonal pattern; 7 of these seasonal patients, and 25 of the non-seasonal patients were currently in depressive phase. Males dominated the sample in both the groups. The seasonal and non-seasonal groups as regards symptomatology, differed only on a few items - decreased libido on SADD, and suicidal ideation and helplessness on HDRS. Atypical vegetative features were not seen in any of the seasonal patients. CONCLUSIONS: SAD is seen at lower latitudes also, although atypical vegetative features are not a prominent part of the symptomatology. LIMITATIONS: The study sampled was obtained from a very select population, and thus does not indicate the prevalence of SAD in India. Secondly, the small sample size precludes any categorical comments of the symptomatology. Moreover, winter and summer depressives were considered as one group. CLINICAL RELEVANCE: Emphasising the presence of SAD in a tropical country where there is relatively less variation in daylight periods, this report forms a base for future studies. It also raises the question of the role of variations in daylight in the aetiology SAD.

Adult↗
PubMed1998

Validation of 24-hour dietary recall: a study in hemodialysis patients.

The 24-hour dietary recall method is frequently used for dietary assessment. However, it is subject to errors by both respondent and observer bias and is largely influenced by the motivation and recall ability of the respondent. The weighment method is regarded as the gold standard for estimating nutrient intake. This study was undertaken to assess the validity of dietary recall in a group of seven maintenance hemodialysis patients, who also had corresponding weighed food records. Actual food consumed and residue were weighed separately. A dietary recall was taken on the next day. Subjects were not allowed to take any food or beverage other than that served during the study period. A good agreement was obtained between dietary recall and the weighed food record (the difference was within 10% of the results of weighment), although there was a consistent underestimate by dietary recall. The results also suggested a training effect since improved recall was noted during the later weeks of the study, although this difference was not statistically significant. Therefore, dietary recall as a method of dietary assessment may be of special value in chronic hemodialysis patients in India, who are usually a motivated and informed group.

Adult↗
PubMed1998

Regulatory interactions between inducible nitric oxide synthase and eicosanoids in glomerular immune injury.

In a rat model of glomerular immune injury induced by administration of anti-glomerular basement membrane antibody and resembling human rapidly progressive glomerulonephritis, we explored whether activation of inducible nitric oxide synthase (iNOS) regulates synthesis of eicosanoids originating from cyclooxygenation or lipoxygenation of arachidonic acid. At early stages (24 hr) of injury, inhibition of iNOS using the selective inhibitor L-N6-(1-iminoethyl) lysine (L-NIL) at doses sufficient to reduce urinary excretion of nitrate/nitrite, reduced glomerular synthesis of the prostaglandins PGE2 and PGI2, but had no effect on that of thromboxane A2 (TxA2). The syntheses of 5-hydroxyeicosatetraenoic acid (HETE), 15-HETE and leukotriene B4 (LTB4) were also reduced. That of 12-HETE remained unchanged. We also explored the effect of arachidonate cyclooxygenation and lipoxygenation eicosanoids on iNOS expression. Administration of the cyclooxygenase (COX) inhibitor, indomethacin, at doses sufficient to inhibit glomerular prostaglandin synthesis, increased iNOS mRNA levels in glomeruli. Administration of the 5-lipoxygenase (5-LO) inhibitor, MK-0591, at doses sufficient to inhibit glomerular LTB4 synthesis also increased iNOS mRNA. The effect of 5-LO inhibition on iNOS expression was more pronounced than that of COX inhibition. In nephritic animals given the iNOS inhibitor, L-NIL, or indomethacin proteinuria worsened. In those given the 5-lipoxygenase inhibitor there was no change in urine protein excretion. These observations point to regulatory interactions between the arachidonic acid and the L-arginine: NO pathways in glomerulonephritis. These interactions are of importance in considering antiinflammatory strategies based on inhibition of iNOS or of specific eicosanoids.

Animals↗
PubMed1998

Plasmapheresis in the treatment of steroid-resistant focal segmental glomerulosclerosis in native kidneys.

A circulating glomerular capillary albumin permeability factor (P(alb)) has been implicated in the pathogenesis of focal segmental glomerulosclerosis (FSGS), which recurs in transplanted kidneys. Plasmapheresis for recurrent FSGS may reduce proteinuria and stabilize renal function if instituted early. We performed six plasmapheresis treatments over 2 weeks in eight patients with a history of steroid-resistant idiopathic FSGS in native kidneys for an average of 12 +/- 2.3 months to determine whether treatment would decrease proteinuria or stabilize renal function. P(alb) was measured before and after plasmapheresis, and patients were followed-up for a mean of 29 +/- 4 months after the development of clinical symptoms. Proteinuria decreased in two of eight treated patients, although only transiently in one of the two. P(alb) improved in one of the two responding patients. Both patients with an improvement in proteinuria had stable renal function at last follow-up. In six of eight patients, there was no improvement in proteinuria despite an improvement in P(alb) (P < 0.0001) after plasmapheresis. At last follow-up, renal function was stable in two of the six nonresponding patients, and four of the six had significant progression of renal disease or were receiving dialysis treatments. These studies suggest that plasmapheresis may diminish proteinuria and stabilize renal function in a small minority of patients with steroid-resistant idiopathic FSGS. However, the lack of a relationship between the removal of the circulating permeability factor and the development of remission in these patients suggests that local factors associated with advanced renal injury or systemic factors unrelated to glomerular permeability play a significant role in determining proteinuria at this late stage of the disease.

Adolescent↗
PubMed1998

Modeling of facet articulation as a nonlinear moving contact problem: sensitivity study on lumbar facet response.

A finite element (FE) based scheme for modeling facet articulation in a spinal motion segment is proposed. The algorithm presented models the facet articulation as a nonlinear progressive contact problem. This algorithm is used to perform a nonlinear FE analysis of a complete L3-L4 motion segment. The role of facets in load transmission through a motion segment and its sensitivity to facet geometric parameters (i.e., spatial orientation of the facets and the gap between the facet articular surfaces) on this load transmission are studied. Compression, flexion, extension, and torsion loads are used in this study. The effect of facetectomy on gross segment response and disk fiber strains is studied by comparing the response of FE models of motion segment with and without facets. Large facet loads are obtained when the motion segment is subjected to torsional and large extension rotations, whereas minimal facet loads are observed under compression and flexion loading. Removal of facets reduces the segment stiffness considerably in torsion and results in higher strain levels in disk fibers. The facet load transmission is sensitive to facet geometric parameters, i.e., spatial orientation and initial facet joint gap. The facet loads increase uniformly with decrease in initial gap between the facet articular surfaces under compression, extension, and torsional loads. The sensitivity to spatial orientation angles of the facet is, however, found to vary with the type of loading. This sensitivity may account for the wide variation in the facet response reported in literature.

Biomechanical Phenomena↗
PubMed1998

Documentation of angiotensin II receptors in glomerular epithelial cells.

Angiotensin II decreases glomerular filtration rate, renal plasma flow, and glomerular capillary hydraulic conductivity. Although angiotensin II receptors have been demonstrated in mesangial cells and proximal tubule cells, the presence of angiotensin II receptors in glomerular epithelial cells has not previously been shown. Previously, we have reported that angiotensin II caused an accumulation of cAMP and a reorganization of the actin cytoskeleton in cultured glomerular epithelial cells. Current studies were conducted to verify the presence of angiotensin II receptors by immunological and non-peptide receptor ligand binding techniques and to ascertain the activation of intracellular signal transduction in glomerular epithelial cells in response to angiotensin II. Confluent monolayer cultures of glomerular epithelial cells were incubated with angiotensin II, with or without losartan and/or PD-123,319 in the medium. Membrane vesicle preparations were obtained by homogenization of washed cells followed by centrifugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of membrane proteins followed by multiscreen immunoblotting was used to determine the presence of angiotensin II receptor type 1 (AT1) or type 2 (AT2). Angiotensin II-mediated signal transduction in glomerular epithelial cells was studied by measuring the levels of cAMP, using radioimmunoassay. Results obtained in these experiments showed the presence of both AT1 and AT2 receptor types in glomerular epithelial cells. Angiotensin II was found to cause an accumulation of cAMP in glomerular epithelial cells, which could be prevented only by simultaneous use of losartan and PD-123,319, antagonists for AT1 and AT2, respectively. The presence of both AT1 and AT2 receptors and an increase in cAMP indicate that glomerular epithelial cells respond to angiotensin II in a manner distinct from that of mesangial cells or proximal tubular epithelial cells. Our results suggest that glomerular epithelial cells participate in angiotensin II-mediated control of the glomerular filtration barrier.

Angiotensin Receptor Antagonists↗
PubMed1998

TNF-alpha increases albumin permeability of isolated rat glomeruli through the generation of superoxide.

Tumor necrosis factor-alpha (TNF-alpha) is a cytokine that plays a central role in inflammation. Glomerular levels of TNF-alpha are elevated in human and experimental glomerulonephritis. Glomerular cells produce and respond to TNF-alpha. One of the mechanisms by which these cells respond to TNF-alpha is through generation of reactive oxygen species. In this study, the effect of TNF-alpha on albumin permeability (P(albumin)) of isolated rat glomeruli and the possible mechanism of this effect were examined. Isolated rat glomeruli were incubated with TNF-alpha (0.4 ng/ml), TNF-alpha with anti-TNF-alpha antibodies, and TNF-alpha with the reactive oxygen species scavengers superoxide dismutase, catalase, DMSO, or dimethylthiourea for 12 min at 37 degrees C, and P(albumin) was calculated. TNF-alpha increased P(albumin) of isolated glomeruli compared with control (0.70 +/- 0.02, n = 25 versus 0.00 +/- 0.05, n = 26), and this effect was abrogated by anti-TNF-alpha antibodies (-0.18 +/- 0.05, n = 23). Superoxide dismutase abolished the increase in P(albumin) (-0.04 +/- 0.11, n = 23), whereas catalase (0.73 +/- 0.08, n = 30), DMSO (0.64 +/- 0.03, n = 10), or dimethylthiourea (0.51 +/- 0.08, n = 10) did not alter the effect of TNF-alpha. These results indicate that TNF-alpha increased P(albumin+)++ of isolated glomeruli and that the mediator of the increased P(albumin) is superoxide. It is concluded that TNF-alpha derived from glomerular or extraglomerular sources can increase glomerular P(albumin) through generation of superoxide and may lead to proteinuria.

Administration, Topical↗
PubMed1998

Prostaglandin E1 in infants with congenital heart disease: Indian experience.

BACKGROUND: E-type prostaglandins (PGE1) can effectively maintain the patency of the ductus arteriosus in neonates. Its use, therefore and be life saving in infants born with ductus dependent congenital heart disease. Although PGE1 is available for over two decade in western world, it has been introduced in India only since April, 1995. OBJECTIVE: To assess the efficacy of PGE1 at our center. SETTING: Hospital based. METHOD: 65 infants with ductus dependent congenital heart disease were included. Age at time of starting PGE1 infusion ranged from 18 hours to 39 days. Forty two of these were more than a week of age, 19 were more than 14 days, and two were above one month. PGE1 was started in an initial dose of 0.05 microgram/kg/min, decreased to 0.005-0.01 microgram/kg/min for maintenance. The indications for use of PGE1 were to increase pulmonary blood flow in 33 cases with pulmonary atresia, tricuspid atresia or critical pulmonic stenosis (Group I); to increase systemic blood flow in 15 cases with coarctation of aorta, hypoplastic left heart and interruption of aortic arch (Group II); to improve mixing in 13 cases of transposition of great arteries (Group III) and for improving the left ventricular volumes by keeping the duct open in 4 cases of transposition of great arteries with intact ventricular septum (Group IV). The efficacy of the drug was assessed by a rise on PaO2 and SaO2% determined for Group I & III, and by appearance of lower limbs pulses in Group II. Left ventricular volumes were serially measured by echocardiography in Group IV cases. RESULTS: The drug was successful in 62 of the 65 cases. There were two failures. One was a 39 days old baby with Ebstein's anomaly of tricuspid valve and pulmonary atresia and other was an eight days old baby with coarctation of aorta and renal failure. In addition, PGE1 could not be continued in another baby due to development of a linear skin rash locally. Side effects included apnea in 5 (9%) of 56 spontaneously breathing patients. Necrotizing enterocolitis, hyperpyrexia and jitteriness was sent in one case each. Six patients died. Two were related to PGE1, one due to failure, another due to its side effects. Definitive procedure were performed in 51 cases electively. PGE1 was used upto 13 days with sustained benefit. CONCLUSIONS: PGE1 is an effective drug for keeping the ductus open in infants with ductus dependent congenital heart disease. It can be used for neonates beyond the first week of life with efficacy. Apnea is a major side effect and close monitoring is essential.

Age Factors↗
PubMed1998

Comparison of the antioxidant action of the alcoholic extract of Rubia cordifolia with rubiadin.

The inhibition of FeSO4 induced lipid peroxidation in rat liver by alcoholic extract of Rubia cordifolia and by one of its constituent rubiadin (1, 3-dihydroxy-2-methyl anthraquinone) (pure form) has been compared. Both have been found to inhibit lipid peroxidation in a dose dependent manner. Whereas the former shows both oxidising and reducing properties with Fe2+ and Fe3+, the latter shows oxidising property only by converting Fe2+ to Fe3+. The former inhibits the oxidation of reduced glutathione while the latter does not.

Animals↗
PubMed1998

Implantation of a 16-channel functional electrical stimulation walking system.

A 16-channel electrical stimulation system was implanted in a 39-year-old patient with T10 paraplegia to restore sit to stand, walking, and exercise functions. System implantation required two surgical sessions. In the first session, the posterior muscle set consisting of bilateral semimembranosus, adductor magnus, and gluteus maximus muscles were exposed and epimysial electrodes sutured at the point of greatest muscle contraction. Closed double helix intramuscular electrodes were implanted in the erector spinae. Two weeks later, epimysial electrodes were attached to the eight anterior muscles consisting of the tibialis anterior, sartorius, tensor fasciae latae, and vastus lateralis with all 16 electrode leads passed to the anterior abdominal wall. The electrodes were connected to two eight-channel stimulators placed in the iliac fossae, and the system was checked by activating the individual muscles. The implanted stimulators received stimulation instructions and power via a radio frequency link to an external control. Stimulation patterns for standing, walking, sitting, and exercise functions were chosen from a preprogrammed menu via a finger key pad. After 3 weeks of restricted patient activity, all electrodes stimulated either the target muscle or had an acceptable spillover pattern. The patient is undergoing a 16-week rehabilitation course of stimulated exercises gradually increasing in intensity. At the conclusion, the goal is to discharge the patient with the system for spontaneous use. Although long term followup is required to determine system reliability, preliminary clinical results indicate that targeted, repeatable, functional muscle contractions in the lower extremity can be achieved with a system consisting of epimysial electrodes.

Adult↗
PubMed1998

Reliability of closed double helix electrode for functional electrical stimulation.

The reliability of a closed double helix electrode in the lower limbs was studied. This electrode is an implanted intramuscular electrode and is used for a totally implantable functional electrical stimulation system. Eighty electrodes were evaluated retrospectively with a mean period of 15 months. The total implant time was 1222 electrode months. The cumulative proportion surviving was 0.934 at 6 months, 0.855 at 1 year, 0.765 at 2 years, and 0.730 after 30 months. Fifteen of 80 electrodes failed, seven showed increasing electrode impedance, and eight had undesirable changes in recruitment. Of the failed electrodes, 2/3 failed during the first 10 months. The reliability was 0.91 at 6 months and 0.80 at 1 year after implantation in all muscle groups. The closed double helix electrode displayed an increased reliability when compared with the open double helix electrode at 6 months, and an equivalent reliability as compared with the electrodes developed by Handa and colleagues at 6 months and 1 year, using the chi squared test for independence. This study suggests that the closed double helix electrode has an acceptable reliability and can be used as a part of a totally implantable functional electrical stimulation system.

Electric Stimulation Therapy↗
PubMed1997

Binding of monomeric and oligomeric porphyrins to human glioblastoma (U-87MG) cells and their photosensitivity.

The binding of monomeric (Hp) and oligomeric (PHE) forms of porphyrin to glioblastoma (U-87MG) cells and the photosensitization of these cells have been studied. Upon binding to U-87MG cells, Hp and PHE exhibited fluorescence bands at 615 and 636 nm, respectively. The fluorescence and absorption spectra of Hp, HpD and PHE, measured in different solvents, suggest that the 615 nm band may arise due to the binding of monomeric as well as aggregated forms of porphyrin to the hydrophilic sites in the cells whereas the 636 nm band may be due to the binding of an aggregated form of porphyrin to the hydrophobic sites. The photosensitivity of cells and photo-induced lipid peroxidation were measured as a function of light dose. Cells were found most photosensitive to PHE followed by HpD and Hp. The photosensitivity of cells correlates well with the fluorescence intensity of cell bound dye at 636 nm. These results suggest that the binding of the oligomeric component of HpD to hydrophobic sites in the cells is responsible for the enhancement in the photosensitivity.

Brain Neoplasms↗
PubMed1997

Gly-Gly-containing triplets of low stability adjacent to a type III collagen epitope.

Collagens, in addition to their structural role in the extracellular matrix, possess a number of functional binding domains. In this study, the binding to collagen of a monoclonal antibody is used as a model to define the molecular features involved in triple-helix interactions with other proteins. Here we report the thermal stability of an overlapping set of triple-helical peptides that includes the epitope recognized by a monoclonal antibody to type III collagen. Although the sequences of these peptides are very closely related, by a translation of a single triplet along the collagen chain, substantial variations in the melting temperatures were observed. These variations in thermal stability could not be readily explained by differences in imino acid content, or in numbers of charged or hydrophobic residues. The results indicate that Gly-Gly-Y triplets, which are adjacent to the epitope, have a strong influence in reducing the thermal stability of triple-helical peptides. Further studies, which were carried out on a set of "host-guest" triple-helical peptides containing different Gly-Gly-Y guest triplets, confirm the destabilizing effect of such tripeptides. The presence of Gly-Gly-Y triplets may play an important role in specific functions of type III collagen by modulating the local triple-helical structure or dynamics.

Amino Acid Sequence↗