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Biomedical subjects

L Ruiz

Publications and source records attributed to L Ruiz.

At least 109 records · Page 6Linked to original sources
PubMed1992

Central analgesic activity of ibuprofen. A neurophysiological study in humans.

Ibuprofen is a widely used non-steroidal anti-inflammatory drug (NSAID). Inhibition of prostaglandin biosynthesis is considered to be the main mechanism of action of this substance. Recently, a central analgesic activity was described in an experimental study. In order to explore the possibility that ibuprofen induces analgesia at central level in humans, we investigated, in a double-blind design, the effects of orally-given 600 mg granular ibuprofen or placebo on nociceptive flexion reflex in normal volunteers. Ibuprofen produced a significant increase, as compared to placebo, in the threshold of the nociceptive reflex. The ratio between subjective pain threshold (Tp) and reflex threshold (Tr) was unchanged after either ibuprofen or placebo administration, indicating that Tp strictly paralleled Tr. These results indicate that ibuprofen displays a central antalgic activity in humans. Different supraspinal structures are probably involved, but the exact mechanisms are still to be clarified.

Administration, Oral↗
PubMed1992

[Epidemiologic, clinical and microbiological characteristics of enterotoxigenic E. coli as the cause of traveller's diarrhea].

We report a study of enterotoxigenic E. coli, that produces heat-labile, heat-stable or both toxins as agent of traveller's diarrhoea. Enterotoxigenic E. coli was isolated from stools of 71 (21%) patients out of a total of 337 traveller's that developed diarrhoea. Of all 71 strains isolated, 51 (15%) produces heat-labile toxin, 10 (3%) heat-stable toxin and 10 (3%) were able to produce both types of toxins. We also analyze the distribution of all cases according to the area visited, as well as the clinical features of traveller's diarrhoea due to enterotoxigenic E. coli.

Adolescent↗
PubMed1990

Role of natural killer cells in the modulation of primary antibody production by purine nucleosides and their analogs.

Previous results from this laboratory demonstrated that treatment of mice with the adenosine analog tubercidin (Tub) reduced natural killer (NK) cell activity while stimulating antibody production whereas the deoxyadenosine analog, 2-fluoroadenine arabinoside-5'-monophosphate (FaraAMP), produced opposite effects; i.e., it stimulated NK cell activity at doses that inhibited antibody formation (Cancer Res. 48, 4799, 1988). Since NK cells have been reported to play a suppressor role in immunoglobulin induction, it was hypothesized that the actions of Tub and FaraAMP on antibody production occurred secondary to their opposing effects on NK cells. To test this hypothesis, abilities of these nucleoside analogs to modulate primary antibody response to sheep red blood cells were evaluated in a C57BL/6 mutant mouse lacking NK cell activity (the beige mutation. C57BL/6-bg/bg). As previously found with C3H/He mice. NK cell activity was inhibited (Tub, doses 2-6 mg/kg/day for 3 days) or stimulated (FaraAMP, doses 75-250 mg/kg/day for 3 days) in heterozygous mice C57BL/6-bg/+. In support of the hypothesis, these nucleosides had no effect on primary antibody formation in the homozygous mutant mice at doses that clearly stimulated (Tub) or inhibited (FaraAMP) this immune response in heterozygous C57BL/6-bg/+ animals. This results was corroborated in C57BL/6 wild-type mice by abrogation of NK cell activity using a monoclonal antibody to the NK cell surface glycophisingolipid, ganglio-n-tetraosylceramide. We conclude that under the conditions of drug administration, modulation of primary antibody formation by Tub and FaraAMP in mice occurs indirectly via NK cells. Similar experiments using the potent ADA inhibitor, deoxycoformycin, indicated that its enhancement of primary antibody formation is independent of NK cell activity.

Animals↗
PubMed1990

A new 5-HT2 antagonist (ritanserin) in the treatment of chronic headache with depression. A double-blind study vs amitriptyline.

The exact relationship between depression and chronic headache remains unclear. Considerable clinical and pharmacological evidence suggests the existence of a common biological terrain. Many antidepressant drugs are effective in the treatment of migraine and chronic headache disorders. Ritanserin, a new very selective serotonin-2 (5-HT2) antagonist, has recently shown both analgesic and antidepressant properties. The present study compares in a double-blind design, the effectiveness of ritanserin and amitriptyline, a well-known antidepressant extensively used in migraine prophylaxis. Thirty-eight patients (30 females and 8 males ranging in age from 20 to 50 yrs) were classified according to the International Headache Society criteria as: patients with chronic tension-type headache (CTH) (11 cases) and patients with coexisting migraine and CTH (MCTH) (27 cases). Only patients with a score equal to or higher than 18 on the Hamilton Rating Scale for Depression (HRSD) were included. Ritanserin was highly effective in reducing Pain Total Index and analgesic consumption in chronic headache, and its activity was similar to that observed during amitriptyline treatment. A significant improvement of HRSD and HRSA (Hamilton Rating Scale for Anxiety) scores was observed during both treatments. The main results of our study concern the demonstration of antiheadache and antidepressive properties of ritanserin. To better define the profile of the patients and their clinical responsiveness to the treatment, dexamethasone suppression test, clonidine test and nociceptive flexion reflex were investigated in our patients. Our data confirm the usefulness of these methods as markers of chronic headache with depression.

Adult↗
PubMed1989

Auditory function in pediatric osteosarcoma patients treated with multiple doses of cis-diamminedichloroplatinum(II).

Serial auditory evaluations were performed in 54 pediatric patients (5 to 18 yr) treated with cis-diamminedichloroplatinum(II) for osteosarcoma. Each course of cis-diamminedichloroplatinum(II) comprised 150 mg/m2 and was administered initially at two weekly intervals for seven courses (3 mo) and subsequently at three monthly intervals for 15 to 21 mo. Overall, 604 courses were administered, and observations were conducted from diagnosis to 6 yr. Bilateral hearing loss was detected in all patients. The loss varied from mild (20 to 40 dB) to profound (greater than 90 dB). Initial losses occurred in the higher frequencies and were also greater at these frequencies. Significant loss was first observed after 300 mg/m2 for frequencies over 4000 Hz and gradually shifted to incorporate the lower frequencies. Hearing loss was permanent.

Adolescent↗
PubMed1986

Influence of dialysis membranes on the convective transport of middle molecules.

Ultrafiltrates from 10 patients in chronic maintenance hemodialysis (7 males and 3 females) were obtained simultaneously using three different membranes: cuprophan, polyacrilonitrile and polysulfone. Middle molecules (MM) chromatographic profiles and total MM amount were determined by gel chromatography and high performance liquid chromatography. The convective transport of MM was similar and not membrane related. Hemofiltration, a predominantly convective solute transfer procedure using high flux membranes such as polyacrilonitrile and polysulfone, in which large amounts of fluids have to be ultrafiltered, is an effective form of MM removal.

Acrylic Resins↗