PubMed · 10072104
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
H B Nielsen. 1999. pH after competitive rowing: the lower physiological range?. https://doi.org/10.1046/j.1365-201x.1999.00485.x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
31P-magnetic resonance spectroscopy (MRS) and a fiberoptic pH meter were used simultaneously to follow the changes in intra- (pHi) and extracellular pH (pHe), respectively, of murine RIF-1 tumors with hyperthermia. Hyperthermia was induced at 34 MHz using the same coil used for MR. The study was carried out until 3.5 hr after hyperthermia. In untreated tumors (n = 29), pHi was always higher than pHe. pHi was reduced after hyperthermia (30 min) at both 42 degrees C and 45 degrees C. pHe registered an increase after 42 degrees C and a decrease after 45 degrees C. The reduction in pHi was larger than the initial differential between pHi and pHe, and the change in pHe was relatively small. Hyperthermia changed the acidity of the intra- and extracellular compartments, such that pHe became more alkaline than pHi by 0.15 +/- 0.13 units after 42 degrees C [pHe (7.20 +/- 0.12) and pHi (7.03 +/- 0.05)], and by 0.12 +/- 0.14 units after 45 degrees C [pHe (6.84 +/- 0.24) and pHi (6.72 +/- 0.19)]. Simultaneous measurements of pH from the intra- and extracellular compartments demonstrated reversal in the pH gradient after hyperthermic treatment.
Colorectal carcinoma presenting during pregnancy is an extremely rare condition associated with a poor prognosis. In this report we studied a patient referred to our hospital at 26 weeks of gestation with the diagnosis of rectal adenocarcinoma. Tumor resection with a colostomy was planned in the attempt to preserve pregnancy until fetal viability could be reached. Blended anesthesia (general and epidural) was chosen to avoid surgical and anesthesiological risks; in fact this technique allows either an optimal block of neurohormonal response or a good control of surgical stress to be obtained. In order to monitor fetal well being during surgery, Doppler evaluations of fetal heart rate and umbilical artery flow velocity waveforms were performed. The patient was dismissed in good health and then rehospitalized at 32 weeks of gestation in order to perform an elective cesarean section. In conclusion we suggest that, with the choice of a good anesthesiological technique and monitoring of fetal well being, surgical treatment in case of rectal cancer could be performed without affecting the course of pregnancy.
Natural infections of mammals with African trypanosomes, such as Trypanosoma brucei, are generally pleomorphic, the population consisting of different forms, termed slender and stumpy forms, that vary in number as the parasitaemia develops. We show that the differentiation of slender into stumpy forms is characterized by the acquisition by the parasite of the ability to regulate its internal pH, even in the face of a large, inwardly directed gradient of H+, as well as a tolerance towards external proteolytic stress. These adaptations effectively abbrogate cellular stress-activated signalling pathways involving adenylate cyclase and glycosylphosphoinositol-specific phospholipase-C mediated release of the surface coat. Although in metabolic terms stumpy forms of the parasite are considered to be preadapted to life in the arthropod vector, these data clearly demonstrate that these forms also possess additional cellular adaptations designed to deal with the immediate and potentially harmful changes in the extracellular environment that occur upon ingestion of a bloodmeal by the tsetse fly vector.