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Biomedical subjects

L Martin

Publications and source records attributed to L Martin.

At least 487 records · Page 27Linked to original sources
PubMed1984

The resistance of the mouse uterine lumen to flushing and possible contamination of samples by plasma and interstitial fluid.

The hydrostatic pressures generated during controlled flushing of the mouse uterus increased at implantation and under conditions of uterine closure. These pressures may be responsible for inducing tissue damage during flushing. The possibility that samples collected by flushing might be contaminated with interstitial fluid or plasma was studied using intravenously administered 51Cr-labelled EDTA and 125I-labelled human serum albumin as markers. The presence of both tracers was detected in all flushings and was greatest in flushings from uteri with luminal closure and early implantation sites. These observations raise serious doubts about the validity of the flushing technique for analysing uterine luminal constituents in mice.

Animals↗
PubMed1984

Acute inhibition of rat myometrial responses to oxytocin by tamoxifen stereoisomers and oestradiol.

The non-steroidal antioestrogen tamoxifen (trans-1-(4-beta-dimethylaminoethoxyphenyl)-1,2-diphenylbut- 1-ene), widely used in the treatment of breast cancer, and its oestrogenic cis-isomer rapidly inhibited contractile responses of isolated rat myometrium to supramaximal concentrations of oxytocin (1.28 X 10(-6) mol/l). Both compounds were effective at concentrations comparable with the plasma concentrations of tamoxifen reached in therapy (i.e. 5 X 10(-7) to 5 X 10(-6) mol/l). Inhibition was too rapid in onset (less than 3 min) to involve changes in RNA transcription and protein synthesis, and was not prevented or reversed by the addition of oestradiol to the bath. We conclude that the inhibition did not involve the classical oestrogen receptor pathway. Oestradiol-17 beta at concentrations above 10(-6) mol/l also inhibited the myometrium and potentiated the effects of the anti-oestrogens. Our experiments suggest that the anti-oestrogens and oestradiol act via a similar route with tamoxifen having an equilibrium affinity approximately tenfold greater than that of oestradiol.

Animals↗
PubMed1983

Polyester prostheses as substitutes in the thoracic aorta of dogs. I. Evaluation of commercial prostheses.

Using canine models, a representative selection of polyester or Dacron vascular prostheses, including woven, knitted, and velour types, were evaluated for their relative healing characteristics and for their structural changes during implantation. Following residence periods ranging from 4 h to 6 months at the site of the thoracic aorta, the dogs were sacraficed, and the grafts were excized for measurement of the thrombogenicity of the flow surface and for pathological examination by light microscopy and SEM. The kidneys were also removed and examined for infarcts caused by any trapped circulating emboli. The extent of healing, the presence of embolizing nuclei, and the thrombogenicity and morphology of the lumen surface were also assessed. The healing characteristics of each type of device proved similar. Velour fabrics exhibited more extensive encapsulation, but frequently their internal capsules failed to incorporate all the fibers. In all cases, cellular development on the lumen was limited to areas contiguous to the anastomoses. The initial porosity of the devices as measured by water permeability did not appear to influence the healing sequence to a significant extent. The grafts did exhibit differences in structural stability depending on whether they were of a knitted or woven construction. We suggest that users consider these different mechanical and structural properties when making their choice of a graft. Despite these differences, we believe that the healing process is far more host dependent than graft dependent.

Angiography↗
PubMed1983

Use of a minicomputer for storing, reporting, and interpreting arterial blood gases/pH and pleural fluid pH.

Blood gas/pH data, like any other laboratory information, are amenable to computerization. This has become more feasible in recent years with the advent of manufacturer-designed blood gas/pH analyzer interfaces and relatively inexpensive mini- and microcomputers. The interface makes possible on-line transmission of data; the computer allows manipulation of the data in virtually any way desired. We have implemented such a system. This system, in continuous use for more than 3 years, permits transmission of blood gas/pH data as soon as the test has been performed, allows storage of the data on floppy disks, and allows reporting of the data in an automated fashion with a printed interpretation. In addition, because our laboratory determines pH in pleural fluid, the latter test has been computerized to provide a separate report and interpretation. Using the computer language BASIC, we programmed this system in-house ourselves. Declining costs of small and powerful personal computers and the use of languages such as BASIC now make it feasible for similar reporting systems to be implemented in many laboratories.

Blood Gas Analysis↗
PubMed1983

[Congenital giant diverticuli of the bladder. Apropos of 3 cases].

The giant congenital vesical diverticulum of the bladder is very uncommon; three observations are described. The clinic symptomatology is ruled by acute retention of urine and by dysuria. The I.V.P. always shows the important reverberation on the renal cavities. In two cases the diagnosis has been done thanks to the cystography. Concerning the third child both clinic and paraclinic symptoms inclined to favour the diagnosis of an abdominal cystic hygroma but the surgical procedure showed it was a bilateral vesical diverticulum. The surgical treatment is made up of endo and latero-vesical diverticulectomy with reimplantation of the homolateral ureter which is always implanted in the posterior pouch. With its clinical, anatomical and physiopathological aspects, the giant congenital diverticulum of the bladder must be differentiated with the little diverticulum.

Child, Preschool↗
PubMed1982

Enamel microstructure determination in hominoid and cercopithecoid primates.

Enamel structure was determined in primate teeth by scanning electron microscopy. It was found that the important organisational features of this tissue can be determined solely from the examination of developing material and that significant differences in internal structure of the mature tissue are reflected in differences in the surface (cell-matrix interface) of the developing tissue. Several very conservative, relatively non-destructive techniques can be used to acquire information from fully formed teeth, whereas the examination of small areas of heavily etched mature tissue samples may be inadequate or provide biased or misleading information. Pattern 3 prism packing occurs predominantly in Hominoidea, Pattern 2 in Cercopithecoidea. Pattern 1 was found in the one callitricid and the one lemur specimen studied.

Animals↗
PubMed1982

Effects of progesterone on uptake and metabolism of 17 beta-estradiol by mouse uterine luminal epithelium.

The influence of progesterone (P4) pretreatment on the uptake and retention of [3H]estradiol-17 beta ([3H]E2) in whole uterus and luminal epithelium was examined in ovariectomized mice. After s.c. injection of 50 ng [3H]E2 uterine, epithelial and epithelial nuclear levels of radioactivity were maximal 3 h post-injection: maximum epithelial levels were sustained from 3 to 6 h in Pa-treated, but not control tissue. P4 treatment did not significantly alter the proportion of epithelial or uterine radioactivity recovered as [3H]E2, or the intracellular distribution of the hormone. Preparation of epithelial suspensions in buffer containing excess 17 beta-estradiol (E2) did not significantly alter their [3H]E2 content. After intraluminal injection of 100 pg [3H]E2 rates of loss from uterine, epithelial and epithelial nuclear preparations did not differ significantly between control and P4-treated tissues. We conclude that P4 does not inhibit E2-induced luminal epithelial mitosis by preventing E2 reaching the epithelial cells and nuclei, by changing its distribution in the tissue, or by increasing its rate of loss from the tissue or its metabolism to less active estrogens like estrone.

Animals↗