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P Gallardo

Publications and source records attributed to P Gallardo.

7 recordsLinked to original sources
PubMed2001

Aquaporin-2, a regulated water channel, is expressed in apical membranes of rat distal colon epithelium.

Aquaporin-2 (AQP-2) is the vasopressin-regulated water channel expressed in the apical membrane of principal cells in the collecting duct and is involved in the urinary concentrating mechanism. In the rat distal colon, vasopressin stimulates water absorption through an unknown mechanism. With the hypothesis that AQP-2 could contribute to this vasopressin effect, we studied its presence in rat colonic epithelium. We used RT-PCR, in situ hybridization, immunoblotting, and immunocytochemistry to probe for AQP-2 expression. An AQP-2 amplicon was obtained through RT-PCR of colon epithelium RNA, and in situ hybridization revealed AQP-2 mRNA in colonic crypts and, to a lesser extent, in surface absorptive epithelial cells. AQP-2 protein was localized to the apical membrane of surface absorptive epithelial cells, where it colocalized with H(+)-K(+)-ATPase but not with Na(+)-K(+)-ATPase. AQP-2 was absent from the small intestine, stomach, and liver. Water deprivation increased the hybridization signal and the protein level (assessed by Western blot analysis) for AQP-2 in distal colon. This was accompanied by increased p-chloromercuriphenylsulfonic acid-sensitive water absorption. These results indicate that AQP-2 is present in the rat distal colon, where it might be involved in a water-sparing mechanism. In addition, these results support the idea that AQP-2, and probably other aquaporins, are involved in water absorption in the colon.

Animals↗
PubMed2000

[Clinical features and response to systemic treatment of primary and secondary episcleritis and scleritis resistant to local treatment].

BACKGROUND: Scleritis and episcleritis may extend to adjacent ocular tissues with blinding consequences and may be associated with potentially lethal systemic disorders. AIM: To evaluate the ocular complications and systemic disease associations of the different types of scleritis and episcleritis. PATIENTS AND METHODS: Forty six patients with refractory scleritis and episcleritis were studied and treated during the period 1991 to 1998. RESULTS: Necrotizing type was the most common and severe category in the scleritis group of patients. A decrease in vision occurred in 58.3% of patients with scleritis v/s a 23.5% of patients with epiescleritis (p < 0.05). Uveitis was present in 35.4% of patients with scleritis and scleromalacia was present in 33.3% (p < 0.05). A specific disease association was uncovered in 51% of scleritis and in 38% of episcleritis patients. Rheumatoid arthritis, primary systemic vasculitic disease and Sjögren syndrome with vasculitis were the most common associated systemic diseases. Three patients with scleritis had tuberculosis. CONCLUSIONS: Scleritis is more severe than episcleritis, and necrotizing scleritis is the most severe type of scleritis. Classification of scleritis and episcleritis provides valuable prognostic information. A meticulous approach for the detection of a specific associated disease must be undertaken. Scleritis associated with vasculitis has a worse ocular prognosis than other non infectious diseases. Cyclophosphamide is the most effective immunosuppressive treatment to control severe ocular involvement.

Adolescent↗
PubMed1999

Bulk milk urea concentrations and their relationship with cow fertility in grazing dairy herds in southern Chile.

Milk urea determination is being used as a broad indicator of protein/energy imbalance in dairy herds. The main purpose of this study was to compare blood and bulk milk urea values in grazing herds, to evaluate their seasonal variation under South Chilean conditions, and to examine their potential relationships with herd fertility. The association between herd blood urea concentration (mean of seven lactating cows) and bulk milk urea concentration (tank containing milk from the previous 24 h) was determined in 21 diary herds. Reference values, seasonal and herd variance, and the frequency of herds with values outside a range of 2.5 to 7.3 mmol/l were determined in bulk milk samples obtained monthly for a period of one year from 82 suppliers at two creameries located in southern Chile. Finally, bulk milk urea was measured every two weeks in samples from 24 herds, and the first service conception rate (FSCR) from 2153 dairy cows was determined. Mean bulk urea concentration was highly correlated with mean herd blood urea concentration (r = 0.95; p < 0.01). Mean urea concentration in the bulk milk samples obtained during one year from 82 herds was 4.9 +/- 1.2 mmol/l, with a range of 1.5 to 11.6 mmol/l. The highest values were found during spring and the lowest values during the summer. There was a high seasonal variation (CV = 13-47%) and between-herd variation (CV = 20-31%). Out of a total of 984 samples, 5.4% had urea values > 7.3 mmol/l and 3.8% had values < 2.5 mmol/l. Of the 82 herds, 27% had values outside the reference interval (2.5-7.3 mmol/l) on two or more occasions. FSCR was lower in herds when the bulk milk urea was > 7.3 mmol/l (50.7%) than in cows, where the urea concentration was < 5.0 mmol/l (73.8%) at the time of insemination. The study concluded that bulk milk urea concentrations provided information similar to herd blood urea concentrations in local grazing dairy herds. There was a high frequency of herds with abnormal values, with large variations between herds and between seasons. Increased milk urea concentrations during spring were associated with lower conception rates.

Animals↗
PubMed1997

Renal identification of cyclooxygenase-2 in a subset of thick ascending limb cells.

The prostaglandin G2/H2 synthase (cyclooxygenase, COX) is a key regulatory enzyme of prostanoid synthesis pathway. The message-encoding COX isoenzymes (constitutive COX-1 and inducible COX-2) have been described in the rat kidney. However, there is scarce information on the localization of COX-2 in the kidney, although it has been recently reported to be localized in the macula densa. The present study was designed to evaluate the localization of COX-2 in adult rat kidneys. Normal rat kidneys (n=10) were fixed in Bouin and were immunostained with specific antibodies against COX-2 by the peroxidase method. The cellular origin of COX-2 was assessed by the immunostaining of serial consecutive sections with antibodies against Na-K-ATPase, Tamm-Horsfall glycoprotein, H-K-ATPase, kallikrein, and macrophages. COX-2 was consistently observed in a subset of tubular cells located in the cortex and in the outer medulla. The staining of serial sections showed that the COX-2+ cells contained both Na-K-ATPase and Tamm-Horsfall, indicating that they corresponded to thick ascending limb (TAL) cells. They were observed at a considerable distance from the corresponding macula densa, although occasionally they were observed close to glomeruli. The COX-2 staining in the TAL cells was not abolished by dexamethasone treatment (1 to 20 mg/kg), suggesting its constitutive expression in normal kidneys. The presence of COX-2 in TAL (a tubular segment postulated to be devoid of COX-1) may contribute to the handling of ions through local production of prostaglandins.

Animals↗
PubMedDate not supplied

[Seroepidemiological study of human hydatidosis, by means of an indirect hemagglutination test in Rio Negro County, X Region, Chile, 1989-1990].

Rio Negro Country (40 degrees 48'-40 degrees 50' South lat.; 73 degrees 12'-73 degrees 13' West long.), is located in the province of Osorno, South of Chile. It has a population of 18,031 inhabitants, with 39% in rural areas. The basic economic activity is cattle raising (cows, pigs). According to reports, prevalence of human hydatidosis in 1988 was 11.1 per 100,000. In order to contribute to a better knowledge of human hydatidosis in Rio Negro County, an indirect hemagglutination test (IHAT) was performed to 509 randomized persons. Five (1.0%) individuals resulted positive.

Adolescent↗