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Biomedical subjects

F Rao

Publications and source records attributed to F Rao.

8 recordsLinked to original sources
PubMed2005

Contributions of the sympathetic nervous system, glutathione, body mass and gender to blood pressure increase with normal aging: influence of heredity.

Body mass and sympathetic activity increase with aging and might underlie blood pressure (BP) elevation. Increased body mass index (BMI) may elevate BP by increasing sympathetic activity. Glutathione (GSH) can decrease BP, and declines with aging. We measured systolic (SBP) and diastolic BP, BMI, plasma (NE(pl)) and urine norepinephrine (NEu), and plasma GSH in n=204 twins across the age spectrum. BP correlated directly with BMI, NEpl, and NEu, but inversely with GSH. Age correlated with BP, BMI, NEpl, and NEu. BP, BMI, NEpl, and NEu were higher in older subjects than younger subjects, whereas GSH was lower with aging. In older subjects with high (above median) NEpl, SBP was 8 mmHg higher than in those of comparable age with low NE. In younger subjects with high GSH, BP was significantly lower than in younger subjects having low GSH. NEu was significantly reduced in young high-BMI subjects vs young low-BMI subjects. The heritability (h2) of NEpl, NEu, and GSH ranged from approximately 50 to approximately 70%, and these biochemical quantities were considerably more heritable than BP. We conclude that increases in sympathetic activity contribute to aging-induced SBP elevations, especially in older females. GSH reductions apparently participate in aging-induced BP elevations, most strongly in males. BMI increases contribute to BP elevations, particularly in younger subjects. BMI elevations apparently raise BP mainly by peripheral mechanisms, with generally little sympathetic activation. Substantial h(2) for plasma GSH, NE, and urine NE suggests that such traits may be useful 'intermediate phenotypes' in the search for genetic determinants of BP.

Adult↗
PubMed2004

Replica exchange molecular dynamics simulations of amyloid peptide aggregation.

The replica exchange molecular dynamics (REMD) approach is applied to four oligomeric peptide systems. At physiologically relevant temperature values REMD samples conformation space and aggregation transitions more efficiently than constant temperature molecular dynamics (CTMD). During the aggregation process the energetic and structural properties are essentially the same in REMD and CTMD. A condensation stage toward disordered aggregates precedes the beta-sheet formation. Two order parameters, borrowed from anisotropic fluid analysis, are used to monitor the aggregation process. The order parameters do not depend on the peptide sequence and length and therefore allow to compare the amyloidogenic propensity of different peptides

Amyloid↗
PubMed2002

Stevens-Johnson syndrome presumably induced by bromhexine. A case report.

The Stevens-Johnson syndrome is a serious form of erythema multiforme, an acute inflammatory pathology with an autoimmune pathogenesis. Its etiology is unknown, although it is thought to have multifactorial causes; nonetheless, many drugs are thought to induce such an immune response. The clinical symptomatology is mainly muco-cutaneous, with a remarkable oral involvement. The authors describe here a case of Stevens-Johnson syndrome involving the ocular, oral, and genital areas, presumably induced by the bromhexine administered to the patient for a viral syndrome.

Adult↗
PubMed2001

Influence of aging on candidal growth and adhesion regulatory agents in saliva.

Although oral candidiasis is frequently seen in the elderly, the factors determining candidal growth have insufficiently been explored. Hence, we examined the influence of aging on candidal adhesion and growth-inhibitory agents in saliva in 45 healthy volunteers and 60 patients with oral candidiasis. Both non-stimulated and stimulated salivary flow rates (SFRs) in the healthy controls decreased with aging. A gradual decrease of SFRs with aging was also observed in the patients, and the SFR levels were markedly lower than those in the controls. Although the salivary glucose levels were almost constant in all age groups, secretory immunoglobulin A and lactoferrin levels in saliva were significantly decreased statistically with age, and a marginal age-associated decrease in transferrin levels was also observed. In addition, the generation of superoxide from neutrophils in saliva and their Candida killing activity decreased with age, and these phenomena were more apparent in the patients. Furthermore, a larger number of Candida adhered to oral keratinocytes obtained from the elderly healthy controls than to those obtained from young controls. Correspondingly, keratinocytes from the aged controls showed more concanavalin-A binding sites than those from the young controls. However, oral Candida did not increase with increasing age in the controls, although an age-associated increase of oral Candida was observed in the patients. Taken together, these results indicate that the decreases of SFRs and salivary anti-candidal factors, suppression of salivary neutrophil function and the increase of candidal adhesion sites on keratinocytes predispose elderly individuals to oral candidiasis.

Adult↗
PubMed2001

Lactoferrin peptide increases the survival of Candida albicans-inoculated mice by upregulating neutrophil and macrophage functions, especially in combination with amphotericin B and granulocyte-macrophage colony-stimulating factor.

To develop a new strategy to control candidiasis, we examined in vivo the anticandidal effects of a synthetic lactoferrin peptide, FKCRRWQWRM (peptide 2) and the peptide that mimics it, FKARRWQWRM (peptide 2'). Although all mice that underwent intraperitoneal injection of 5 x 10(8) Candida cells with or without peptide 2' died within 8 or 7 days, respectively, the survival times of mice treated with 5 to 100 microg of intravenous peptide 2 per day for 5 days after the candidal inoculation were prolonged between 8.4 +/- 2.9 and 22.4 +/- 3.6 days, depending on the dose of peptide 2. The prolongation of survival by peptide 2 was also observed in mice that were infected with 1.0 x 10(9) Candida albicans cells (3.2 +/- 1.3 days in control mice versus 8.2 +/- 2.4 days in the mice injected with 10 microg of peptide 2 per day). In the high-dose inoculation, a combination of peptide 2 (10 microg/day) with amphotericin B (0.1 microg/day) and granulocyte-macrophage colony-stimulating factor (GM-CSF) (0.1 microg/day) brought prolonged survival. With a combination of these agents, 60% of the mice were alive for more than 22 days. Correspondingly, peptide 2 activated phagocytes inducing inducible NO synthase and the expression of p47(phox) and p67(phox), and peptide 2 increased phagocyte Candida-killing activities up to 1.5-fold of the control levels upregulating the generation of superoxide, lactoferrin, and defensin from neutrophils and macrophages. These findings indicated that the anticandidal effects of peptide 2 depend not only on the direct Candida cell growth-inhibitory activity, but also on the phagocytes' upregulatory activity, and that combinations of peptide 2 with GM-CSF and antifungal drugs will help in the development of new strategies for control of candidiasis.

Amphotericin B↗
PubMed2000

Malignant pheochromocytoma. Chromaffin granule transmitters and response to treatment.

Chromaffin granule transmitters such as chromogranin A and catecholamines have been used in the diagnosis of pheochromocytoma, but the diagnostic and prognostic value of chromogranin A have not been explored in malignant pheochromocytoma. We evaluated these transmitters in patients with pheochromocytoma (n=27), both benign (n=13) and malignant (n=14). Patients with benign pheochromocytoma were studied before and after surgical excision (n=6), whereas patients with malignant pheochromocytoma were evaluated before and after combination chemotherapy with regular cycles of cyclophosphamide/dacarbazine/vincristine (nonrandomized trial in n=9). During treatment, patient responses to chemotherapy were divided according to anatomic and clinical criteria: responders (n=5) versus nonresponders (n=4). Plasma chromogranin A rose progressively (P<0.0001) from control subjects (48.0+/-3.0 ng/mL) to benign pheochromocytoma (188+/-40.5 ng/mL) to malignant pheochromocytoma (2932+/-960 ng/mL). Parallel changes were seen for plasma norepinephrine (P<0.0001), though plasma epinephrine was actually lower in malignant than benign pheochromocytoma (P=0.0182). In bivariate analyses, chromogranin A, norepinephrine, and epinephrine discriminated between pheochromocytoma and control subjects (all P<0.0001), whereas in a multivariate analyses, norepinephrine was the best discriminator (P:=0.011). Chromogranin A was significantly different in benign versus malignant pheochromocytoma on both bivariate (P=0.0003) and multivariate (P:=0.011) analyses. After excision of benign pheochromocytoma, chromogranin A (P=0.028), norepinephrine (P=0.047), and epinephrine (P=0.037) all fell to values near normal. During chemotherapy of malignant pheochromocytoma (n=9), plasma chromogranin A (P=0.047) and norepinephrine (P=0.02) fell but not epinephrine. In 5 responders to chemotherapy, there were significant declines in chromogranin A (P=0.03) and norepinephrine (P=0.03) but not epinephrine; in 4 nonresponders, none of the transmitters changed. Plasma chromogranin A varied longitudinally with tumor response and relapse. We conclude that plasma chromogranin A is an effective tool in the diagnosis of pheochromocytoma, and markedly elevated chromogranin A may point to malignant pheochromocytoma. During chemotherapy of malignant pheochromocytoma, chromogranin A can be used to gauge tumor response and relapse.

Adolescent↗
PubMed1994

Arytenoid motion evoked by regional electrical stimulation of the canine posterior cricoarytenoid muscle.

Anatomical studies have demonstrated that the posterior cricoarytenoid muscle in the dog is composed of three bellies. These bellies are termed vertical, oblique, and horizontal on the basis of their orientation. The purpose of this study was to show whether each of these bellies can move the vocal fold in different ways. Ten anesthetized dogs underwent laryngectomies while paralyzed with curare. The posterior cricoarytenoid muscles were then exposed by dissecting the overlying esophageal mucosa. Electrical stimulation was applied to each belly, and the motion of the arytenoid cartilage was measured. Because the oblique belly overlies the vertical belly, they were usually stimulated together. It was found that the vertical and oblique bellies rock the arytenoid backwards while sliding it laterally, thus causing a maximal dilation of the airway. The horizontal belly caused a swiveling motion of the arytenoid. It is proposed that the vertical and oblique bellies normally cause vocal fold abduction during respiration, while the horizontal belly primarily is used to adjust finely the position of the vocal process during phonation. Because the human posterior cricoarytenoid is also composed of separate bellies it, too, may have distinct functions.

Animals↗