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Biomedical subjects

J M Martinez

Publications and source records attributed to J M Martinez.

At least 19 recordsLinked to original sources
PubMed1990

A randomized double-blind clinical trial on the effectiveness of helium-neon laser in the prevention of pain, swelling and trismus after removal of impacted third molars.

The effect of helium-neon (He-Ne) laser on the prevention of pain, swelling and trismus following the removal of an impacted third molar was studied in 100 patients randomly allocated to receive He-Ne laser, ibuprofen or placebo in a prospective double-blind parallel clinical trial. Trismus was significantly reduced in the He-Ne laser and ibuprofen treatment groups. Pain was significantly less in the ibuprofen group with regard to He-Ne laser and placebo groups. Swelling was the same in the three treatment groups.

Adult↗
PubMed1989

Arterial blood gas changes in panic disorder and lactate-induced panic.

Lactate infusions were conducted in 12 male panic patients and 8 male normal controls with arterial catheters in place to reassess previously reported acid-base changes based on venous blood samples. The analysis of arterial pH, carbon dioxide pressure, and bicarbonate concentration confirmed most venous findings. At baseline, before the infusion, venous blood shows evidence of mixed chronic and acute respiratory alkalosis in patients while arterial blood gasses are most consistent with developing acute respiratory alkalosis. During the infusion both bloods are consistent with mixed metabolic and respiratory alkalosis with the patients hyperventilating more than normal controls and panicking patients hyperventilating more than nonpanicking patients. Arterial blood seems more sensitive than venous blood in detecting baseline differences between panicking and nonpanicking patients. A baseline arterial carbon dioxide pressure of 40 mmHg or higher and an arterial pH below 7.40 may predict no subsequent panic to lactate infusion.

Acid-Base Equilibrium↗
PubMed1988

Slowed information processing in multiple sclerosis.

Sixteen patients with a definitive diagnosis of multiple sclerosis (MS) and an equal number of matched controls were administered tests of memory and information processing speed. Results indicated a significant long-term verbal memory impairment in patients with MS, with spared short-term memory and memory scanning. Speed of information processing was evaluated with the Paced Auditory Serial Addition Test. The results for the two highest rates of presentation revealed significantly impaired processing in the MS group. Performance at the higher rates and retrieval of information from long-term memory were significantly correlated. These results suggest that slowed information processing is a deficit that contributes to long-term memory impairment in patients with MS.

Adult↗
PubMed1988

Multiple memory deficits in patients with multiple sclerosis. Exploring the working memory system.

Some patients with multiple sclerosis (MS) demonstrate impaired memory. A group of 16 patients with MS who were mildly to moderately affected (Kurtzke Expanded Disability Status Scale Score = 3.8) were studied, and they were compared with a matched control group on tests of "working memory." The working memory system was explored by evaluating the amount of information that can temporarily be held in a buffer system during encoding. Results indicated that patients with MS have difficulty in processing information at the level of a hypothesized articulatory loop in working memory. This deficit was correlated with their retrieval of verbal information from long-term memory, as well as how accurately they processed verbal information presented at a rapid rate. There was no significant relationship between ratings of MS severity or number of plaques visualized on magnetic resonance imaging scans and the degree of working memory deficit.

Adult↗
PubMed1988

Epinephrine stimulates prostaglandin synthesis by bullfrog lung from warm-acclimated, but not cold-acclimated, animals.

Exogenous prostaglandins (PGs) have been shown to have differing effects on frog lung contractility. In this study, prostaglandin synthesis was measured in lung tissues from warm-acclimated (WA, 22 degrees C) and cold-acclimated (CA, 5 degrees C) American bullfrogs, Rana catesbeiana, incubated for 30 min at 5 degrees or 22 degrees C. Media were assayed by radioimmunoassay for PGE2, PGF2 alpha, 6-keto PGF 1 alpha (the metabolite of PGI2), and thromboxane (TX)B2 (the metabolite of TXA2). PGE2 was produced in greatest quantity by tissues from WA and CA animals, at both incubation temperatures. Epinephrine stimulated PGE2, PGF2 alpha, and TXB2 synthesis at 22 degrees C but only stimulated PGE2 production at 5 degrees C. In tissues from CA frogs, epinephrine did not stimulate prostaglandin synthesis at either incubation temperature. Ibuprofen (10(-5) M) inhibited basal and epinephrine-stimulated prostaglandin synthesis in tissues from WA frogs incubated at 22 degrees C. The beta receptor antagonist propranolol (10(-6) M) blocked the epinephrine-stimulated synthesis of PGE2, PGF2 alpha and TXB2, suggesting epinephrine stimulates prostaglandin synthesis through beta receptor activation. The absence of stimulation by epinephrine in lung from CA animals, but not in 5 degrees C incubations of tissues from WA animals, suggests that a modification of beta receptors occurs during prolonged cold exposure.

Acclimatization↗
PubMed1988

Complicated coital cephalalgia. Three cases with benign evolution.

Three patients with a history of migraine and type-II coital cephalalgia with signs of vertebrobasilar deficiency are presented. Extensive studies including angiography did not show any vascular malformation. Together with the few reports in the literature our cases outline a benign form of complicated coital cephalalgia, possibly resulting from ischaemic disturbances triggered by haemodynamic changes occurring in orgasm.

Adult↗
PubMed1988

[Anatomo-clinical study of Behçet's syndrome with involvement of the central nervous system].

The authors report a patient with Behçet disease who developed severe central neurological disturbances. The M.R.I. was largely coincident with the distribution of the lesions verified in the neuropathological examination, while CT only shows an hypodense lesion in basal ganglia with contrast enhancement. The neurological symptoms did not respond to a treatment with prednisone and azathioprine. The main histopathological findings are similar to those described by previous observers. Reactive histiocytic infiltration with severe lymphocytic phagocytosis, probably related to immunosuppressor treatment, was also observed.

Azathioprine↗
PubMed1985

Normalization of venous pH, pCO2, and bicarbonate levels after blockade of panic attacks.

Recent evidence suggests that hyperventilation may be associated with spontaneous panic attacks in patients with panic disorder. This is reflected in abnormal patterns of blood gas and blood pH levels in these patients. In this study, absolute levels and variances of pH, pCO2, and bicarbonate were compared between controlled patients before and after successful pharmacological treatment. The results indicate that successful treatment of panic disorder results in a normalization of pH, pCO2, and bicarbonate levels.

Adult↗
PubMed1984

Hypoglycemia and panic attacks.

Many patients with panic disorder believe hypoglycemia causes their symptoms. Of 10 patients with panic disorder given sodium lactate to induce panic, none had evidence of low blood sugar levels when they began to experience anxiety symptoms.

Adolescent↗
PubMed1981

Effects of isoproterenol on bradycardia-dependent intra-His and left bundle branch blocks.

The electrophysiologic study of a patient with a history of fainting showed first- and second-degree Mobitz type I intraatrial and intra-His (IH) bundle blocks. Tachycardia and bradycardia-dependent IH block and bradycardia-dependent left bundle branch block were also present. Bradycardia-dependent block was probably caused by slight hypopolarization plus a slow rising slope of phase 4 depolarization and a shift of the threshold potential toward zero. Two months later a second electrophysiologic study was performed before, during and after administration of i.v. isoproterenol (IP). Shortening of atrium-His (AH1) and IH (H1H2) conduction time during faster heart rates caused by IP infusion may be related to its hyperpolarizing effect. Simultaneously, a shifting to the left of both bradycardia-dependent IH and left bundle branch block ranges was recorded during vagally induced cardiac slowing. These findings suggest that IP produces an increase in the slope of phase 4 depolarization of the His bundle and left bundle branch fibers and a simultaneous and concordant effect at both levels of the intraventricular conduction system.

Bradycardia↗
PubMed1980

Seroepidemiological studies of malaria in pregnant women and newborns from coastal El Salvador.

A cohort of 113 women and their newborns from the coastal area of El Salvador were studied longitudinally to estimate malaria incidence and indirect fluorescent antibody (IFA) response to malaria infection. The district in which the study was conducted had an estimated annual parasite index of 600/1,000 inhabitants, and all malaria infections were treated immediately with a 4-aminoquinoline. In the third trimester of pregnancy, the IFA response to Plasmodium falciparum was significantly depressed. As a result of antimalarial therapy and depressed immune responsiveness, 49% (P. vivax) and 53% (P. falciparum) of the pregnant subjects had a malaria IFA titer less than 1:20 at the time of delivery. Malaria IFA crossed the placenta to the fetus with a step-down of approximately a 4-fold dilution, except for the step-up noted in the P. falciparum titer for 17 of 116 newborns. Due to the overall low prevalence and intensity of maternal IFA, a titer of at least 1:20 was passed to only 23% (P. vivax) and 45% (P. falciparum) of newborns. Passively-acquired malaria IFA degraded with a half-life estimated between 43 and 52 days. During follow-up of infants to 6 months of age, no protection from malaria resulting from passively-acquired antibody could be demonstrated. Because of the limited transplacental immunization of these newborns with antimalarial antibody, it appears that passive immunity can exert little effect on the incidence of infant malaria in coastal El Salvador.

Antibodies↗
PubMed1976

Calcium and the control of discrete wave latency in the ventral photoreceptor of Limulus.

1. Discrete, transient depolarization (discrete waves) of the ventral photoreceptor of the horseshoe crab, Limulus, occur spontaneously in the dark adapted photoreceptor and are also evoked by light. They form the basic events which comprise the receptor potential. A brief, low energy flash of light evokes variable numbers of discrete waves which have variable latencies. Evidence suggesting that discrete wave latency reflects the kinetics of the chemical reactions of phototransduction is reviewed. 2. The concentration of extracellular Ca influences both the average discrete wave latency and its variability. Lowering extracellular Ca prolongs the latency and increases its variability. Increasing extracellular Ca has the opposite effect. 3. Changes in discrete wave latency caused by changes in extracellular Ca require 10--15 min to become fully manifest, whereas when the concentration of extracellular K is increased the photoreceptor achieves a steady-state depolarization in 10-15 sec. 4. Iontophoresis of the Ca-chelating agent EGTA into the photoreceptor increases both the average discrete wave latency and its variability. Iontophoresis of Ca-EGTA mixtures may either increase or decrease discrete wave latency and its variability depending upon the proportion of Ca mixed with EGTA. 5. It is suggested that the concentration of intracellular rather than extracellular ionized Ca is the prime factor indicating discrete wave latency. The effects of changing extracellular Ca can be explained if the photoreceptor is permeable to Ca in the dark and if it maintains a low intracellular Ca concentration by virtue of active metabolic processes (a pump-leak system). 6. Lowering the temperature of the photoreceptor also has the dual effect of increasing discrete wave latency and its variability. However, effects of lowering temperature and Ca simultaneously are greater than the sum of the two effects in individually. This suggests that Ca may be a reactant in the chemical process of phototransduction. 7. Changing the concentration of extracellular Ca does not change the quantum efficiency of discrete wave production. A previous study showed that quantum efficiency is not changed by temperature. Thus, once initiated by the absorption of light, the reactions that subserve phototransduction may be forced to completion. Ca probably exerts its influence by changing one or more rate constants in the reaction sequence.

Action Potentials↗