PubMed Health⌕ Search

Biomedical subjects

C Talbot

Publications and source records attributed to C Talbot.

12 recordsLinked to original sources
PubMed1992

Renal, respiratory and ionic regulation in Atlantic salmon (Salmo salar L.) kelts following transfer from fresh water to seawater.

Atlantic salmon may return to the sea after spawning in fresh water. These fish, known as kelts, reportedly show a limited ability to hypoosmoregulate. However, this study shows that fresh-water-adapted kelts exposed to seawater demonstrate rapid adaptation (within 48 h) in osmoregulatory parameters to values characteristics of seawater-adapted salmonids. The urine flow rate falls from 1.2 to 0.2 ml.kg-1.h-1 within 24 h. Over the same period, urine osmolality increases from 48 mosmol.kg-1 to become isosmotic with the plasma, and Mg2+ secretion by the kidney tubules elevates the urine concentration from 0.5 to 100 mmol.l-1. As is characteristic for marine teleosts, kelts drink seawater and process the ingested water in the gut to replace body water lost by osmosis to the hyperosmotic medium. Seawater exposure causes a marked hypoxia, arterial oxygen tension falling by 43% within minutes and persisting for at least 4 days at this low level. This is associated with large changes in blood pH and acid-base balance. The physiological mechanisms involved in adaptation to a hyperosmotic external medium are discussed, and the osmoregulatory capacity of kelts is compared with that of salmon at other stages of the life cycle.

Adaptation, Physiological↗
PubMed1991

Intestinal water transport in juvenile Atlantic salmon (Salmo salar L.) during smolting and following transfer to seawater.

1. The rate of mucosal to serosal water movement was measured in vitro in non-everted midgut segments in Atlantic salmon (Salmo salar L.) during parr-smolt transformation (February-July) and following transfer of smolts to seawater in May. 2. The rate increased significantly during smolting from 5.61 microliters/cm2/hr in the parr (February) to 11.03 microliters/cm2/hr in smolts in May. 3. Measured at intervals over a period of 20 days in seawater, the rate of water transport was not significantly different from that found in the freshwater-adapted smolts (11.20 microliters/cm2/hr). 4. Intestinal water transport is sodium-linked and inhibited by ouabain but is not stimulated by cortisol.

Adaptation, Physiological↗
PubMed1991

Optimization of human endothelial cell attachment to vascular graft polymers.

Endothelial cells (EC) covering the blood-contacting surface of a prosthetic material could potentially enhance the subsequent nonthrombogenicity of the surface. In order to create such a surface, the EC must become attached to the surface, spread and ultimately form a monolayer. In this study we examined several factors that influence these processes. On ePTFE surfaces, surface pretreatment with human serum for 30 minutes at a concentration of 1.4 gm percent protein resulted in significantly more attached EC when compared to other concentrations or when compared to fetal calf serum or human serum albumin. The rate of EC spreading was strongly influenced by temperature, with a maximum occurring at 37 degrees C. During real-time video microscopy, it was noted that the rate of EC attachment and spreading was primarily dependent on arrival of the EC to the surface rather than attachment and spreading. Thus as a method of increasing EC delivery, the concept of filtering EC onto the graft lumenal surface was tested by pressurizing the graft lumen to speed EC delivery to the surface. This technique produced a 2 to 5-fold increase in EC attachment when compared to gravity forced cell deposition. We conclude that an ePTFE graft can be rapidly endothelialized using these simple measures.

Biocompatible Materials↗
PubMed1989

Semiconductor diode laser endophotocoagulation.

We successfully used a semiconductor diode laser to deliver endophotocoagulation burns to the retina of a rabbit. The diode laser employed emits light at a wavelength of 817 nm (near infrared). It has a power output of up to 1.0 W in the continuous-wave mode, equivalent to the capability of current argon laser endophotocoagulators. A standard, commercially available fiberoptic endophotocoagulation probe was used to deliver the laser burns. We used power settings ranging from 300 mW to 400 mW and exposure times of 0.1 to 0.2 seconds to produce chorioretinal burns that appeared clinically and histopathologically indistinguishable from those induced with conventional wavelengths. This new laser system has the decided advantages over traditional endophotocoagulators of being much smaller, less costly, and requiring no water cooling, without sacrificing power output or ease of delivery.

Animals↗
PubMed1986

Body composition of Atlantic salmon (Salmo salar L.) studied by neutron activation analysis.

This paper describes the measurement of whole body Ca, Cl, K, N, Na, O and P in Atlantic salmon parr, adults and kelts by neutron activation analysis (NAA). This technique is based on counting the specific gamma activity in samples which is present naturally or is produced by neutron irradiation. Body composition (fat, mineral, protein and water) are estimated from these data. NAA has advantages over chemical methods with the potential for in vivo measurements. Anthropogenic 137Cs was found in sea-water (SW) salmon but not found in the freshwater (FW) stages (parr and kelts). Presence of this isotope in fish caught in FW indicates recent SW residence.

Aging↗
PubMed1985

An evaluation of suloctidil in the prevention of deep vein thrombosis in neurosurgical patients.

Suloctidil (200 mg t.i.d.) was compared with placebo in a randomized, double-blind trial to assess its value in preventing deep venous thrombosis (DVT) in high-risk neurosurgical patients, comprising 136 patients with brain or spinal tumour, head or spinal injury, or subarachnoid or intracranial hemorrhage. 125I fibrinogen leg scanning and impedance plethysmography were performed for up to 14 days to detect DVT. The two groups were also evenly balanced for DVT risk factors. Seventeen of 68 patients (25%) (95% confidence interval, 15-35%) treated with suloctidil and 12 of 68 patients (21%) (95% confidence interval, 11-32%) treated with placebo developed deep venous thrombosis. This observed difference in outcomes is not statistically significant (X2 = 1.096; p = 0.30). The estimated 95% confidence interval for the true difference in the incidence of DVT between suloctidil-treated and placebo-treated patients ranges from an 11% benefit in favour of suloctidil to an 18% benefit in favour of placebo. Major deep vein thrombosis occurred in two patients on suloctidil and three patients in the placebo group; there were no fatal pulmonary emboli during the 14-day study period, during which time four patients in each group died of non-thromboembolic complications. There was no observed difference in hemorrhagic complications. Long-term outcomes at three-months follow-up were similar between the two treatment groups. It is concluded that there is no real evidence that suloctidil (200 mg t.i.d.) is an effective regimen for the prevention of DVT in high-risk neurosurgical patients.

Brain Neoplasms↗
PubMed1985

Sodium balance in eggs and dechorionated embryos of the Atlantic salmon Salmo salar L. exposed to zinc, aluminium and acid waters.

Ionic regulation of eyed eggs of Atlantic salmon was studied using intact eggs and embryos from which the chorion and perivitelline fluid had been removed, a preparation which remained in good condition for at least 2 weeks. Both intact eggs and embryos in freshwater showed similar Na+ influx rates (0.0064 and 0.01 microM g-1 hr-1, respectively) but Na+ efflux rates (0.0024 and 0.0064 microM g-1 hr-1, respectively) were greater in embryos, suggesting that the perivitelline fluid which is known to bind cations has an important function in preventing Na+ loss from the yolk and embryo. Over 90% of the egg Na+ is located in the yolk and embryo but only about 10% is exchangeable while the chorion contains about 8% Na+ which is non-exchangeable. Both eggs and embryos in acid water at pH 4, in Zn2+ 5 mM l-1 and in aluminium 1 mM l-1 showed greatly reduced Na+ uptake but eggs in 10 microM l-1 aluminium or 100 microM l-1 Zn2+ showed normal Na+ balance while embryos were normal in 10 microM l-1 aluminium but showed reduced Na+ uptake in 100 microM l-1 Zn2+. It is concluded that the chorion and perivitelline fluid have a capacity to protect the embryo from metal ions and acid water.

Aluminum↗
PubMedDate not supplied

Synphasic tablets in Canadian practice: a phase-IV multicenter study.

The performance of a low-dose triphasic oral contraceptive (OC) in the first four cycles of use was evaluated by 1,326 primary-care physicians and specialists across Canada in a phase-IV postmarketing trial. Data were available from 5,460 women who completed 19,756 cycles of use with Synphasic. The incidence of intermenstrual bleeding characteristically decreased over the four cycles to 10% in women who were first-time users of OCs, to 14% in women who had previously used OCs but had discontinued use until this trial, and to 16% in women who had switched from another OC to Synphasic. The women reported a low incidence of headache, nausea, weight gain, breast complaints, and acne while receiving Synphasic. The results demonstrate good endometrial control with Synphasic and a high level of patient acceptance.

Adolescent↗