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Biomedical subjects

E Gonzalez

Publications and source records attributed to E Gonzalez.

At least 163 records · Page 9Linked to original sources
PubMed1987

Continuous respiratory support in quadriplegic children by bilateral phrenic nerve stimulation.

Three children, aged 6-10 years, in whom cervical cord injury at the C1-C2 level resulted in apnoea had bilateral implantation of diaphragm pacemakers. With periods of gradual conditioning of the diaphragm muscle to low frequency stimulation and slow respiratory rates they adapted to continuous ventilatory support by simultaneous stimulation of both hemidiaphragms without evidence of fatigue, so far for periods of 23-47 months.

Apnea↗
PubMed1987

Postamputation neuromas and other symptomatic stump abnormalities: detection with CT.

One of the potentially troublesome sequelae of limb amputations is the development of stump neuromas at the severed ends of major nerves. The ability to define them and to distinguish them from other causes of stump pain is of considerable clinical significance. Computed tomography was performed on ten lower limb amputees with stump pain. Five patients had neuromas that were manifest as focal or generalized alteration in the caliber, size, or contour of the nerve trunk in the affected stump. The remaining five patients each had an abnormality detected; these abnormalities included heterotopic bone formation, popliteal artery aneurysm, lipoma, scar tissue, and abscess in the contralateral limb.

Adult↗
PubMed1986

Synthesis and release of catecholamines by the cat carotid body in vitro: effects of hypoxic stimulation.

The role of catecholamines (CAs) in cat carotid body chemoreception has been controversial. On the basis of pharmacological experiments, it would appear that endogenous dopamine (DA) may act either as an inhibitory or excitatory transmitter. Neurochemical studies on the effects of natural stimulation on the release of carotid body CAs in the cat have also been inconclusive. In the present study, we have characterized the synthesis and release of CAs in the in vitro cat carotid body preparation in response to different levels of hypoxic stimulation and have correlated these measures with the chemosensory activity of the carotid sinus nerve. The synthesis of [3H]DA and [3H]norepinephrine was linear for at least 4 h in carotid bodies incubated with their natural precursor [3H]tyrosine. Synthesis of both [3H]CAs plateaued when the [3H]tyrosine concentration in the media reached 40 microM, which is a concentration similar to that found in cat plasma. Exposure of the animals to an atmosphere of 10% O2 in N2 for 3 h prior to removal and incubation of the carotid bodies with [3H]tyrosine resulted in an approximately 100% increase in the rate of [3H]DA synthesis but no change in [3H]norepinephrine synthesis. This selective increase in [3H]DA synthesis was not detected when [3H]dihydroxyphenylalanine was used as precursor. Carotid bodies first incubated with [3H]tyrosine and later superfused with solutions equilibrated with different gas mixtures (0-100% O2 in N2) exhibited an increase in [3H]DA release and carotid sinus nerve discharge which were inversely related to the oxygen concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Pneumocystography as an aid in the diagnosis of cystic lesions of the breast.

Pneumocystography is used in Europe in managing breast cysts. This involves aspiration, air insufflation, and completion mammography. Pneumocystography allows accurate delineation of the cyst wall and contents. Pneumocystograms that do not demonstrate intracystic lesions negate the need for cyst excision in many cases. Microcalcifications may become visible after pneumocystography. Intracystic masses, positive cyst fluid cytology, bloody cyst fluid, cyst recurrence, or evidence of an extrinsic mass compressing the cyst are all indications for operation. Intracystic cancers can and do metastasize. Pneumocystography may be beneficial in detecting these cancers.

Air↗
PubMed1986

The importance of the Fc receptors for IgA in the recognition of IgA by mouse liver cells: its comparison with carbohydrate and secretory component receptors.

The numbers of murine hepatocytes and Kupffer cells with receptors for human polymeric (pIgA) or monomeric IgA (mIgA) were determined by rosette formation with immunobeads coated with human pIgA or mIgA. About 63% of hepatocytes were found to express receptors for pIgA. Receptors for mIgA were also found in a significantly lower percentage of hepatocytes (50%). Only about 10% of Kupffer cells had this type of receptor. Blocking studies performed with purified human immunoglobulins suggested that both cells expressed a receptor that recognized the Fc portion of IgA (either pIgA or mIgA). In addition, murine multimeric MOPC-315 IgA strongly inhibited in a dose-dependent fashion the pIgA and mIgA rosette formation by both cells. When cells were incubated in the presence of a rabbit antiserum to secretory component (SC), only pIgA rosette-forming hepatocytes were partially inhibited. No such inhibition was seen when an antiserum to human IgG was used. Both galactose and mannose monosaccharides failed to inhibit the IgA rosette formation by either type of cell. These results show that murine hepatocytes, besides having SC receptors for polymeric IgA, also express receptors for the Fc portion of IgA. The carbohydrate receptors did not seem play any role in the recognition of IgA. The fact that Kupffer cells exclusively present Fc alpha R suggests that monomeric and polymeric IgA, either in form of immune complexes or not, are handled in a different manner by the liver cells.

Animals↗
PubMed1986

[Sources of cattle infection with atypical mycobacteria and the frequency of their isolation from healthy slaughter animals in Cienfuegos Province, Cuba].

Studied were a total of 322 samples of water, feed, and grass vegetation with soil from a region where there were records of unspecific tuberculin reactions with cattle. Investigations were also carried out on viscera and lymph nodes of 120 slaughtered cattle. It was found that the atypical acid-fast mycobacteria were widely spread in some regions of Cuba: 42.5% were found in grass samples, 37.5%--in soil samples, 35.0%--in water ones, and 9.6% in feed samples. Atypical mycobacteria were isolated in 35.0% of the cases with internal organs and lymph nodes of slaughtered healthy animals. Established were as many as ten species of such bacteria, prevailing being M. aquae B, M. aquae A, M. smegmatis, and M. phlei. Suggested is the preparation of an allergen from selected strains of atypical mycobacteria to carry out differential tuberculin tests where suspected tuberculin reactions were recorded in the practice.

Abattoirs↗
PubMed1985

Diagnosing breast cancer using frozen sections from Tru-cut needle biopsies. Six-year experience with 162 biopsies, with emphasis on outpatient diagnosis of breast carcinoma.

Experience in a 6-year period with 162 frozen sections from needle biopsies of the breast is reported. The technique was used mainly to diagnose breast cancer in outpatients. The results of frozen section on needle biopsies are compared with frozen sections of excisional biopsies. The sensitivity of detection in breasts containing carcinoma using frozen section of breast needle biopsies was 77%. The sensitivity of detection of carcinoma in needle biopsies subsequently shown to contain carcinoma by paraffin section was 92.8%. The specificity of frozen sections of breast needle biopsies was 86.4% and was devoid of false-positive results. Interpretation of frozen sections of needle biopsies of breast lesions is reliable when performed by experienced surgeons and handled and interpreted by experienced pathologists.

Biopsy↗
PubMed1984

Effects of low pH on synthesis and release of catecholamines in the cat carotid body in vitro.

The rates of dopamine and noradrenaline synthesis in the cat carotid body (c.b.) are 5.9 +/- 0.58 pmol/c.b./2 h and 0.3 +/- 0.02 pmol/c.b./2 h, respectively. The synthesis is doubled when the organs are incubated at pH 7. Similarly, low pH induces a release of dopamine from the c.b. which is proportional to increased activity in the carotid sinus nerve.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Some properties of the reactive hydroxylysyl residues in collagen: their possible role in nucleation during fibril formation.

Native or heat-denatured collagens were incubated under controlled conditions of temperature and pH with variable molar ratios of KCNO or 2,4,6-trinitrobenzene sulphonic acid. The results obtained suggest that a small number of free amino groups are available for reaction on the native protein, while all the free amino groups react on the denatured protein. The highly reactive free amino groups in the native protein are hydroxylysine residues and have an abnormally low pK of 8.5 which is conformation dependent; this pK becomes normalized upon denaturation of the protein. The reactive hydroxylysines appear to be located in basic regions that could be the nucleation sites needed for fiber formation in the heat-gelation assay; the modified protein does not form stable fibrils upon heating at 37 degrees C and the few fibers formed are not stabilized after reduction with NaBH4. Our results also suggest that the triple helix in collagen is heterogeneous with respect to the reactivity of free amino groups and that several discrete transition temperatures are observed with two main breaks at 30 degrees C and at 37 degrees C, respectively.

Animals↗
PubMed1984

Bilateral comparison of generalized lichen planus treated with psoralens and ultraviolet A.

Ten patients with generalized lichen planus were treated with oral 8-methoxypsoralen photochemotherapy (PUVA) in a bilateral comparison study. Five patients (50%) cleared completely on both sides and required no maintenance treatment after a follow-up of up to 4 years. Three other patients (30%) improved at least 50% of their previous involvement. Most of the patients experienced symptomatic improvement of the treated side by the second week of the treatment. Two patients reacted adversely and exacerbated while receiving treatment to one side of the body. While preliminary, this bilateral comparison study demonstrates that PUVA is an effective therapy for generalized, symptomatic lichen planus and suggests that maintenance therapy might not be required once complete clearance is attained. Caution should be exercised, however, since some patients might develop an exacerbation of their disease with PUVA.

Adult↗
PubMed1984

Histologic alterations of psoralen- and longwave ultraviolet radiation-exposed skin.

Histologic changes in skin exposed to psoralen photochemotherapy (PUVA) may be classified as acute or chronic. The acute set of histologic alterations includes changes associated with lesion regression and PUVA toxicity. The chronic set of changes related primarily to the side effects of PUVA therapy. In psoriatic epidermis, morphologic evidence of cellular hyperactivity ceases with accompanying loss of psoriasiform hyperplasia, whereas in other inflammatory disorders the lymphocytic infiltrate is cleared in the epidermis and papillary dermis. In short-term therapy, changes include melanocytic hyperplasia and increased activity with marked keratinocyte hypermelaninosis. In skin chronically exposed to PUVA, all cutaneous compartments are affected with an epidermal maturation disorder, melanocyte activation, as well as dermal collagen and elastic tissue degeneration, some of which persist after cessation of therapy.

Humans↗
PubMed1983

Possible role of sulphatide in the K+-activated phosphatase activity.

A microsomal fraction rich in (Na+ + K+)-ATPase has been isolated from the outer medulla of pig kidney. (Mg2+ + K+)-activated ouabain-sensitive phosphatase activity was studied in this preparation treated with arylsulphatase, an enzyme that specifically hydrolyzes ceramide galactose-3-sulphate. The activity of phosphatase was inactivated in proportion to the amount of sulphatide hydrolyzed. A maximum inactivation of ouabain-sensitive activity was obtained with 60% of the sulphatide content hydrolyzed. The inactivation caused by arylsulphatase was partially reversed by the sole addition of sulphatide. The evidence offered in this paper about sulphatide function in the sodium pump mechanism supports the idea that sulphatides are involved in the K+-activated phosphatase, a partial reaction of the (Na+ + K+)-ATPase.

Animals↗