Browsing by Author "MUNOZ, M"

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    CYTOCHROME-OXIDASE ACTIVITY IN THE NUCLEUS OF THE TRACTUS-SOLITARIUS OF THE CAT
    (1992) TORREALBA, F; MUNOZ, M
    We studied the cytochrome oxidase (CO) activity in the nucleus of the tractus solitarius (NTS) of normal cats and in animals subjected to unilateral removal of vagal and glossopharyngeal afferents. In normal cats CO activity was higher in the ventrolateral, dorsolateral, interstitial and ventral NTS subnuclei. The dorsal, medial, commissural and gelatinosus subdivisions showed lower levels of CO activity. The peripheral deafferentation up to 47 days did not reduce the CO activity, suggesting an important role for the central inputs in deter-mining the neural activity of the NTS.
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    DETERMINATION OF THE DISTRIBUTION AND ABUNDANCE OF THE LIMPET SCURRIA SCURRA ON THE STIPES OF THE KELP LESSONIA-NIGRESCENS IN CENTRAL CHILE
    (1989) MUNOZ, M; SANTELICES, B
    In Central Chile, the limpet Scurria scurra lives in open cavities on the stipes of the kelp Lessonia nigrescens. Several characters in this association, including number of limpets per cavitity and number and position of cavities along the stipes, are highly fixed. In this study we use explanations suggested elsewhere for equivalent specific patterns in other limpet-kelp associations a testable hypothesis for the Scurria-Lessonia relationship. Results indicate that the limpet has a highly predictable location in the kelp bed, decreasing in abundance with decreasing tide levels and with increasing time exposed to waves. Usually one limpet is found per scar and only one scar per stripe, generally excavated under the first stipe bifurcation. Limpets can wander out of the cavities during high tides. They show no significant ontogenic changes in radular structure or in excavating capacities. They could occupy any new suitable stipe one they are dislodged due to accidents while wandering out of the cavity or because of strip breakage. In addition, close to 20% of the limpet population survives stipe breakage by remaining attached to the stipe stumps. Field experiments indicate that friction between the stipes of L. nigrescens is the most important factor determining the number and distribution of cavities on the stipes. A comparison of our findings with results on other limpet-kelp associations indicate that generalizations are restricted to a few common features only. In each association there are several additional specific characters which seemingly represent the outcome of specific life history adjustments of each interacting partner.
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    EFFECT OF A CALCIUM INHIBITOR, NIFEDIPINE, ON EXERCISE TOLERANCE IN PATIENTS WITH ANGINA-PECTORIS - A DOUBLE-BLIND-STUDY
    (1981) CORBALAN, R; GONZALEZ, R; CHAMORRO, G; MUNOZ, M; RODRIGUEZ, JA; CASANEGRA, P
    The effect of nifedipine on exercise tolerance was studied in 30 patients with stable angina and positive graded exercise testing. Treadmill exercise testing was performed on each of 5 consecutive days. Placebo or nifedipine, 10 mg sublingually, was given 30 min before exercise on the 3rd day. The following day the intervention was reversed in a double-blind manner. Angina was abolished by nifedipine but not by placebo in 12 patients (40%). The time to onset of angina in the remaining patients increased from 4.1 .+-. 0.4 (SEM [standard error of mean]) to 6.7 .+-. 0.6 min (P < 0.001). Time to ST depression .gtoreq. 2 mm increased from 4.0 .+-. 0.3 to 5.4 .+-. 0.5 min, while duration of exercise increased from 6.3 .+-. 0.3 to 8.2 .+-. 0.4 min (P < 0.001). The maximum heart rate was 145 .+-. 3.3 with nifedipine and 122 .+-. 3.8 min-1 with placebo (P < 0.01). Resting systolic blood pressure decreased 30 min after nifedipine administration from 131 .+-. 3.4 to 106 .+-. 2.9 mm Hg (P < 0.01). Maximal systolic blood pressure during exercise was lower with nifedipine (127 .+-. 4.8 mm Hg) than with placebo (155 .+-. 8.6 mm Hg, P < 0.01). Nifedipine significantly improves the exercise tolerance of patients with stable angina pectoris by decreasing peripheral vascular resistance and myocardial O2 demand.
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    EFFECTS OF THE BRYOZOAN MEMBRANIPORA-TUBERCULATA (BOSC) ON THE PHOTOSYNTHESIS AND GROWTH OF GELIDIUM-REX SANTELICES ET ABBOTT
    (1987) CANCINO, JM; MUNOZ, J; MUNOZ, M; ORELLANA, MC
    Several species of Membranipora commonly occur on brown and red algae. It is currently believed that these bryozoans could affect growth of the host plant by modifying incident light. In the present study, we report on the changes that occur in both intensity and quality of light passing through colonies of M. tuberculata (Bosc.) and on the effects of bryozoans on growth of the host plant. M. tuberculata decreases photon-flux density by up to 56% of the incident light and slightly affects the quality of the incident light. Although the bryozoan reduces the photosynthetic rate of Gelidium rex Santelices et Abbott, it does not have a net effect on algal growth. It is concluded that the effects of epifauna on algal growth depend on the nature of the algal structure colonized. Therefore, it cannot be predicted a priori that encrusted thalli should grow at a slower rate than nonencrusted thalli.
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    MODIFICATION OF SYNAPTIC EFFICIENCY - EXPERIMENTS IN BLATTA-ORIENTALIS
    (1975) DAVIDOVICH, A; MUNOZ, M; LUCO, JV