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J L Ochoa

Publications and source records attributed to J L Ochoa.

69 records · Page 4Linked to original sources
PubMed1983

Peripheral projections of fascicles in the human median nerve.

Intraneural microstimulation combined with microneurography was employed to study the degree of mixing of muscle and skin nerve fibres at two levels in the human median nerve, and to delineate the area of skin supplied by a fascicle. It was found that about half the fascicles at upper arm level appeared to supply exclusively skin or muscle, while the remainder were considerably committed to one or the other. Further, the projection territories of skin nerve fascicles, both at the wrist and in the arm, tended to be discrete, confluent areas covering no more than 20 per cent of the median nerve territory. At the wrist fascicular territories usually resembled the innervation area of a single palmar digital nerve while in the upper arm they tended to cover a digital interspace. These findings suggest that most of the rearrangements of spinal root fibres into terminal nerve branch groupings occur at brachial plexus level, while the intraneural fascicular plexus may act as a safety mechanism allowing for nondermatomal overlap at proximal level.

Adult↗
PubMed1983

Cerebral localisation function from the input of single mechanoreceptive units in man.

The accuracy of the cerebral localisation function from the input of single mechanoreceptive units was studied in the hand and forearm of human subjects by means of microneurography and intraneural microstimulation (INMS). The mean distance separating the projected field of a sensation evoked by INMS at liminal amplitude from the receptive field of the activated unit (interfield distance, or IFD) was found to vary from 2.6 mm for SA I units in the fingertips to 23.4 mm for SA I units in the forearm. A less pronounced proximodistal IFD gradient was found for quickly adapting units. IFD values for each skin region were comparable with those obtained by a point localisation test directly on the skin. This indicates that functional gradients exist for inputs from single mechanoreceptive units, and that stimulus localisation hardly improves when numerous units are coactivated.

Action Potentials↗
PubMed1982

Purification and partial characterization of an agglutinin from Phaseolus coccineus var. 'alubia'.

An agglutination from seeds of 'alubia', a Mexican strain of Phaseolus coccineus, has been purified by affinity chromatography using physically entrapped stroma. The protein appears to be homogeneous by electrophoresis, molecular sieve chromatography and ultracentrifugation. A molecular species of approx. Mr 112,000, with S values of 6.25, 4.52, 4.63 and 4.65 at pH 2.5, 4.5, 7.0 and 9.5, respectively, consisting of four similar subunits (28 kDa), and containing 20% W/W glucosamine, is found to be responsible for the hemagglutinating capacity of 'alubia' extracts. No sugar able to inhibit agglutination has been found. The possibility that hemagglutination by Ph. coccineus var. 'alubia' involves cell receptors other than simple carbohydrate structures must therefore be considered.

ABO Blood-Group System↗
PubMed1980

Paraesthesiae from ectopic impulse generation in human sensory nerves.

Intraneural microelectrode recordings were obtained from sensory nerve fascicles in awake normal subjects experiencing post-ischaemic paraesthesiae. Spontaneous activity in afferent fibres started about half a minute after re-establishment of circulation; it peaked by the second minute and slowly waned thereafter. This parallelled the time course and intensity of the perceived paraesthesiae. During the most intense stage of paraesthesiae, single unit discharges consisted of prolonged bursts of high-frequency impulses (200-300 imp/s) lasting for 1 to 7 seconds. Repeated bursts became progressively shorter and often exhibited marked rhythmicity as paraesthesiae became weaker. Hyperventilation increased paroxysmal firing and paraesthesiae, whereas ischaemic periods repeated at short intervals exhausted the impulse generating mechanism. The outcome of local anaesthetic blocks indicated that the impulses were generated ectopically along the nerve fibres previously subjected to ischaemia and not primarily from the receptors in the skin. The high frequency of the discharge and the quality and distribution of various paraesthesiae suggest that sensory units with myelinated fibres participated in the paroxysmal discharge; normal activity, but no ectopic discharges were recorded in unmyelinated fibres. It is proposed that the perverted quality of paraesthesiae is due to an abnormal spatio-temporal pattern of ectopic impulses from different types of sensory units. creating a chaotic percept consisting of an assortment of sensations referred in irregular succession to multiple areas.

Adult↗
PubMed1979

Hydrophobicity of lectins. I. The hydrophobic character of concanavalin A.

The hydrophobicity of Concanavalin A has been estimated by its tendency to adsorb to hydrophobic adsorbents. Experiments varying temperature, salt concentration and hydrophobicity of the absorbent were consistent with accepted criteria of hydrophobic interaction between biomolecules and hydrophobic ligands. The biological significance of the hydrophobic character of Concanavalin A is also discussed.

Adsorption↗
PubMed1979

The mechanisms of lectin-mediated cell agglutination.

The interaction between lectins and cells is a well established phenomenon. However, the way by which this interaction occurs is still unclear and published observations are sometimes contradictory. This article attempts to reconciliate the available information concerning this problem in order to find support for a new model of lectin-mediated agglutination of cells. The traditional idea favours the carbohydrate-directed interaction as the main reason of binding of lectins to the cell surface. Nevertheless, lectins molecules are so diversified in physical chemical and biological properties, as well as in structure, that such generalization cannot be stated without risk. Furtheremore, the agglutination mechanism itself is too complex to assume that lectins are only functional "bridges" that hold two cells together. The effect noticed when agglutination is studied with different cells and different lectins at various conditions, suggest that other factors are to be taken into account.

Agglutination↗
PubMed1978

Muscle hypertrophy after partial denervation: a human case.

While undergoing long-term physiotherapy, a 41 year old woman with a chronic S1 radiculopathy developed progressive, painless enlargement of the weak calf. Gastrocnemius muscle biopsy disclosed changes of partial denervation and reinnervation, with small groups of type I and type II atrophic muscle fibres and abundant hypertrophic fibres of both types but mostly type II. It is postulated that, in addition to comprensatory work-induced type II muscle fibre hypertrophy, there was an element of (type I) stretched-induced hypertrophy of denervated fibres, a condition well recognised experimentally but not documented in man.

Adult↗
PubMedDate not supplied

Anti-inflammatory activity of Debaryomyces hansenii Cu,Zn-SOD.

BACKGROUND: Cu,Zn-superoxide-dismutase, Cu,Zn-SOD, can be obtained from different sources with different anti-inflammatory activities. In this study we compared the anti-inflammatory capacity of the marine yeast Debaryomyces hanseii Cu,Zn-SOD (Dh-SOD) with that of bovine erythrocytes (Be-SOD) in a preventive and a therapeutic fashion. METHODS: Edema was induced by carrageenan injection into the rat hind paw and was evaluated using a mercury plethysmograph. Development of the inflammatory process was followed by volume displacement at time 0 (carrageenan injection), 1, 2, 3, 4, 5, 6, 9, 12, and 24 h thereafter. Three different SOD doses were used in preliminary experiments to prevent edema: 10, 100, and 1,000 U/kg. RESULTS: The results indicate that, at the lowest dose (10 U/kg), both SOD samples are effective in reducing inflammation in both the prostaglandin and amplification phases (-24.8% and -17.5% in the case of Be-SOD, and 11.8% and -18.7% in the case of Dh-SOD, respectively) (p < 0.05). At 100 U/kg, Be-SOD also shows good anti-inflammatory activity in all edema phase (-27.1% in the serotonin phase; -19.4% in the prostaglandin phase; and -20% in the amplification phase) (p < 0.05), but Dh-SOD was less effective (-10.9%, -9.1%, and -5.7%). At the highest dose tested (1000 U/kg), Dh-SOD was, again, more effective than Be-SOD in all three edema phases (-33.1% and -1.5%; -17.9% and -2.6%; and -13.8% and 6.7%, respectively) (p < 0.05). When evaluated as a therapeutic alternative, single doses of Dh-SOD at 1,000 U/kg, and Be-SOD at 100 U/kg, both showed good anti-inflammatory activities (-31.7% and -23.5%, respectively) (p < 0.05). CONCLUSION: For therapy purposes alone, Dh-SOD appears to be a better anti-inflammatory agent than Be-SOD in carrageenan-induced edema.

Animals↗
PubMedDate not supplied

Effect of superoxide dismutase from bovine erythrocytes on different activity parameters in adjuvant-induced arthritis.

BACKGROUND: The purpose of this work was to evaluate the effect of superoxide dismutase (SOD) on primary swelling, lipoperoxidation, body thymus, and spleen weight in the adjuvant-induced arthritis (AIA) model in rats. METHODS: Orally and intraperitoneally administered SOD (100 U/kg) from bovine erythrocytes, as well as naproxen (40 mg/kg) and dexamethasone (25 mg/kg), were evaluated against placebo. RESULTS: Primary edema was not decreased by SOD; in contrast, naproxen and dexamethasone showed good anti-inflammatory activity. Lipoperoxidation increased 1.8, 2.5, and 2.8 times with intraperitoneal SOD, naproxen, and dexamethasone administration, respectively, while oral SOD decreased lipoperoxidation levels to approximately one-half of that found in the control group. Body weight increased with SOD but decreased with dexamethasone. Naproxen did not change the animal weight. Thymus weight remained unchanged with SOD and naproxen, while it decreased with dexamethasone. Spleen weight remained the same with SOD, but increased with naproxen and decreased with dexamethasone. No side effects were observed in the SOD group, whereas 20% of the rats in the naproxen group died of gastrointestinal hemorrhage, and 50% of the rats in the dexamethasone group, of pulmonary infection. CONCLUSIONS: In conclusion, SOD showed no anti-inflammatory activity but decreased lipoperoxidation when administered orally. No deleterious effects in primary and secondary immunologic organs were observed with this agent.

Animals↗
PubMedDate not supplied

Superoxide dismutase and Naproxen in the very late phase of carrageenan induced edema in rats.

BACKGROUND: Rat hind-foot carrageenan induced edema (CIE) is a widely used model to evaluate anti-inflammatory drugs. It shows two well-defined phases, however a third not fully characterized phase has been observed. Superoxide dismutase (SOD) is a free radical-scavenger with anti-inflammatory activity. In our country there is not a specifically designed instrument to evaluate edema in CIE. METHODS: Edema was induced by intraplantar injection of carraageenan. Fours groups were evaluated: placebo, two different doses of SOD, and Naproxen. Edema was evaluated by a specially designed mercury plethismograph. Intensity of the inflammatory reaction was determined during the classical early and late phases and during the third very late phase. RESULTS: All treatments, but higher dose of SOD, showed good anti-inflammatory activity throughout early, late, and very late phases. Naproxen was more effective than SOD during first and second phase, however this difference disappeared during the third phase. In terms of equimolar basis the enzyme appeared 1,800 time more potent than Naproxen. Mercury plethysmometer performance was fine. CONCLUSIONS: The anti-inflammatory activity of SOD and Naproxen is extended until the very late phase in the CIE model. In this bioassay, this long lasting activity of the enzyme should be ascribed to a mechanism supplementary to its free radical-scavenger property. SOD may be indeed an alternative treatment in inflammatory diseases.

Animals↗