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Biomedical subjects

E Gonzalez

Publications and source records attributed to E Gonzalez.

At least 145 records · Page 8Linked to original sources

MRI of postamputation neuromas.

Magnetic resonance imaging of 24 symptomatic lower limb amputations revealed that postamputation neuromas were easily diagnosed in above-the-knee amputees. Visualization of nerve trunks in below-the-knee amputees was difficult due to greater compactness of calf muscles. Neuromas on magnetic resonance imaging appeared ovoid or rounded and were usually heterogenous and isointense with muscle. Magnetic resonance imaging also showed additional causes of stump pain such as scar formation, fat in atrophied muscles, soft tissue abscesses, osteomyelitis, and hematomas.

Adult↗

Treatment of tattoos by Q-switched ruby laser. A dose-response study.

Tattoo treatment with Q-switched ruby laser pulses (694 nm, 40 to 80 nanoseconds) was studied by clinical assessment and light and electron microscopy. Fifty-seven blue-black tattoos or portions thereof (35 amateur and 22 professional) were irradiated with 1.5 to 8.0 J/cm2 at a mean interval of 3 weeks. Substantial lightening or total clearing occurred in 18 (78%) of 23 amateur tattoos and 3 (23%) of 13 professional tattoos in which the protocol was completed. Response was related to exposure dose. Scarring occurred in one case, and persistent confettilike hypopigmentation was frequent. Optimal fluence was 4 to 8 J/cm2. Clinicohistologic correlation was poor. Q-switched ruby laser pulses can provide an effective treatment for tattoos.

Adult↗

Dose-response effect of sublingual captopril in hypertensive crises.

Forty-one patients, presenting in the Emergency Service of the Hospital General y Clinico, Tenerife, with symptoms of hypertensive crisis and supine diastolic blood pressure (DBP) greater than 120 mm Hg, were studied. They received 12.5 mg of sublingual captopril and 30 minutes later, if diastolic blood pressure (DBP) was not 100 mm Hg or less, the same dose was repeated by the same route. Supine systolic blood pressure (SBP), DBP and heart rate (HR) were monitored at 0, 5, 10, 15, 30, 45, 60, and 120 minutes after each administration of captopril. In 27 patients (66%) had a satisfactory response (DBP less than or equal to 100 mm Hg), after a single dose, less than 30 minutes after administration, which persisted at 120 minutes. In 14, a second administration was necessary after 30 minutes, and a satisfactory response to the second dose, defined again as DBP reaching values of 100 mm Hg or less, was achieved in 12 of them (29% of the total group). In two patients (5% of total) no full response was obtained. The observed pattern of response suggests that a sublingual dose of 25 mg of captopril is the minimum effective dose, but it is also possible that administration of 12.5 mg of sublingual captopril at 10 to 15 minute intervals, perhaps up to a maximum dose of 37.5 mg, might be considered as an alternative treatment in hypertensive crises.

Administration, Sublingual↗

Effects of aging on the pituitary-thyroid axis in the dog.

The effects of advancing age on basal serum concentrations of thyroxine (T4) and thyrotropin (TSH), on T4 responses to TSH, and on TSH responses to thyrotropin-releasing hormone (TRH) were studied in beagle dogs. A total of 27 female dogs belonging to four age-groups were used: prepubertal (11.4 +/- 0.2 (SD) weeks), adult (2.1 +/- 0.3 years), middle-aged (6.5 +/- 0.2 years), and old (12.4 +/- 0.3 years). There was no significant difference between serum T4 concentrations of prepubertal (4.3 +/- 0.1 microgram/dl, mean +/- SE) and adult dogs (4.1 +/- 0.1 microgram/dl). Also, the decreases between adulthood and middle age (16.01%) and between middle age and old age (23.5%) were not significant, but serum T4 levels in the old dogs (2.6 +/- 0.2 micrograms/dl) were significantly (p less than 0.01) lower than those in the adult dogs. Serum cortisol levels showed a progressive increase with advancing age and were significantly higher in old animals (20.1 +/- 2.4 ng/ml) compared to those in the adults (13.4 +/- 1.2 ng/ml). There were no significant differences in serum TSH concentrations among the four age-groups. A single i.v. injection of TSH (0.15 IU/kg B.W.) raised serum T4 levels in the prepubertal animals by more than 45% in 1 h and by more than 100% in 2 h. T4 responses to TSH in the adult dogs were similar to those in the prepubertal dogs but were greatly delayed and subdued in the middle-aged and old animals. A single i.v. injection of TRH (5 micrograms/kg B.W.) increased serum TSH levels in the prepubertal animals by more than 120% in 15 min. These increases were less in the adult (74.8%) and middle-aged (21.3%) animals, and a significant increase (24.6%) in the old animals did not occur until 30 min after TRH treatment. This study demonstrates that, with advancing age, marked alterations occur in the regulation of the T4-TSH system in the dog.

Aging↗

Assessment of the effectiveness of glove use as a barrier technique in the dental operatory.

To assess the effectiveness of routine glove use as a barrier technique in the dental operatory, the relationship between frequency of glove use and hepatitis B infection was examined. Hepatitis B screening results and information on infection control practices of 1,109 dentists who attended the 1985 annual session were compiled and statistically analyzed. The results showed that 18% of the dentists wore gloves routinely, 65% wore gloves intermittently, and 17% never wore gloves. Frequency of glove use was related to hepatitis B infection (P less than .01), with dentists who never wore gloves being infected more than twice as often as dentists who wore gloves routinely. Dentists with less frequent glove use and more years in practice had a higher incidence of hepatitis B infection (P less than .0001).

Dentists↗

Sandblaster's lung with mycobacterial infection.

This report describes the development of alveolar silico-lipoproteinosis complicated by Mycobacterium kansasii infection in a previously healthy man who worked as a sandblaster. Alveolar silico-lipoproteinosis is a rare disease that usually is fatal within 1 year of onset of symptoms. There is a high incidence of mycobacterial infection, half being caused by atypical organisms.

Humans↗

Comparative permeability of canine visceral and parietal pleura.

To determine the permeability of canine pleural mesothelium, visceral and intercostal parietal pleura from mongrel dogs was carefully stripped from the underlying tissue and mounted as a planar sheet in a Ussing-type chamber. The hydraulic conductivity (Lp) was determined from the rate of volume flux in response to hydrostatic pressure gradients applied to either the mucosal or serosal surface of the pleural membrane. The diffusional permeability (Pd) of radiolabeled water, sucrose, inulin, and albumin was determined under equilibrium conditions from the unidirectional tracer flux. The Lp of the visceral pleura was 0.39 +/- 0.032 (SE) X 10(-4) ml.s-1.cmH2O-1.cm-2 and that Lp of parietal pleura was 1.93 +/- 0.93 X 10(-4) ml.s-1.cmH2O-1.cm-2 (P less than 0.001). The Pd of the visceral pleura ranged from 12.21 +/- 0.45 X 10(-4) cm/s for 3H2O to 0.34 +/- 0.03 X 10(-4) cm/s for [3H]albumin. The Pd of the parietal pleura for water and sucrose was similar to that of the visceral membrane, whereas its Pd for the larger inulin and albumin molecules was greater than that of visceral pleura (P less than 0.01). A spontaneous potential difference could not be detected across either membrane. The relatively higher parietal pleural Lp and Pd for larger solutes is probably due to the presence of stomata in this membrane. These results indicate that both the parietal and the visceral pleura are extremely permeable tissues which offer little resistance to water and solute flux.

Albumins↗

Desipramine and cutaneous reactions in pediatric outpatients.

The association of adverse cutaneous effects with administration of the tricyclic antidepressant drug desipramine was systematically reviewed in a clinic population of 205 child psychiatry outpatients over a 3-year period. Transient maculopapular rashes developed in 12 children and adolescents treated with desipramine. The rashes had a benign course, disappearing completely in 2 to 7 days, and were not associated with clinical or chemical hepatitis or any other physical symptoms.

Adolescent↗

Role of platelet-activating factor in adriamycin-induced nephropathy in rats.

The effect of steroids, heparin and specific PAF-acether antagonists (BN 52021 and triazolobenzodiazepines) on proteinuria and renal histological changes induced in rats by adriamycin was studied. Adriamycin evoked a marked proteinuria that was unaffected by methylprednisolone and slightly reduced by heparin. In contrast, adriamycin-injected rats treated with PAF-acether antagonists had a low proteinuria, if any, and no ultrastructural glomerular alterations. These data suggest that PAF-acether could play a major role in the occurrence of proteinuria and that PAF-acether antagonists might provide a new therapeutic approach in certain human nephropathies.

Animals↗

Amniotic band sequence and its neurocutaneous manifestations.

Six new cases of the amniotic band sequence with a wide spectrum of defects were studied with respect to neurocutaneous manifestations, including histopathologic characteristics. Fetuses 1 and 2 were stillborn. Despite severe craniofacial involvement, infants 3 and 4 survived 1 yr and 22 months, respectively. Patients 5 and 6 had only limb defects. Craniofacial and neurologic manifestations of our longer-survival patients with severe craniofacial anomalies were microcephaly, encephalocele, micro- or anophthalmia, mental retardation, hydrocephaly, seizures, EEG abnormalities, impaired body temperature control, impaired vision, hypertonia, and other psychomotor deficits. Characteristic cutaneous manifestations seen in our patients were clefting, schisis, fibrous strings, ring constriction, lymphedema. pseudosyndactyly, and intrauterine amputation. Histologic examination of the amniotic bands attaching to the skin showed autolyzed amnion in patient 2, erosion of the band into upper dermis in patient 1, and fibrosis underlying the constricted areas in patient 5. Prenatal diagnosis by ultrasonography is possible in patients with severe craniofacial defects (patient 2). A brief review of the literature is offered.

Abnormalities, Multiple↗

Collagenolytic activity in experimental cirrhosis of the liver.

Collagenolytic activity has been measured in insoluble sediments of normal and CCl4-induced cirrhotic rat liver. Two techniques were used: in one assay, the insoluble liver sediments were incubated with a radioactively labeled exogenous substrate; in the other assay, the endogenous collagen present in the insoluble liver sediments served as the substrate. Animals in various stages of development of CCl4-induced cirrhosis were used. Results suggest that in rat liver cirrhosis collagenolytic activity assayed with both techniques appears to increase when expressed as weight of collagen degraded in 24 hr. On the other hand, when the data are corrected for the variable amounts of collagen present in the insoluble liver sediments and expressed as weight of collagen degraded in 24 hr per unit weight of total collagen incubated, collagenolytic activity is shown to be significantly decreased below the normal level and to remain so for prolonged periods.

Animals↗

Mechanisms for termination of the action of dopamine in carotid body chemoreceptors.

The possible presence of a high affinity uptake mechanism for dopamine and the metabolism of this amine was investigated in the rabbit carotid body. The type I cells of this sensory organ contain high levels of dopamine and share with sympathetic nerve endings (which possess a high affinity uptake mechanism for catecholamines) the properties of being presynaptic catecholaminergic elements, but also have in common with chromaffin cells from intact adrenal medulla (which lack a high affinity catecholamine uptake) a similar embryological origin and ultrastructural appearance. Our experiments revealed only a low affinity uptake process (Km = 6.76 X 10(-4) M [3H]dopamine; Vmax = 1.84 X 10(-9) mol [3H]dopamine/mg protein/min) in the rabbit carotid body. In agreement with our kinetic findings, the uptake of [3H]dopamine was found to be independent of the Na+ concentration in the incubation media. The efflux from the tissue of incorporated [3H]dopamine was very fast (88% wash-out with a half-time of 4 min). DOPAC was the principal catabolite of dopamine in the carotid body, and the organ exhibited a very low capacity for norepinephrine synthesis. Neither chronic carotid sinus nerve section nor chronic sympathectomy modified the uptake of [3H]dopamine, suggesting that the lack of expression of a high affinity uptake was not a consequence of trophic suppression by the neural innervation of the organ. We conclude that overflow, or wash-out, of released dopamine may be quantitatively the most important mechanism for the inactivation of this putative neurotransmitter in the rabbit carotid body.

Animals↗