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Biomedical subjects

H Alvarez

Publications and source records attributed to H Alvarez.

At least 55 records · Page 3Linked to original sources
PubMed1994

Mesencephalo-diencephalic angioanatomy in arteriovenous malformations. Endovascular management of transmesencephalic vs subependymal supply in 954 cases between 1982 and 1994.

This report presents the arteries of the mesencephalo-diencephalic region and their different role in the supply to the cerebral structures. Among them, the authors distinguish the subependymal and transmesencephalic arteries to which they pay a special attention since these vessels present a specific angiographic aspect. The importance of their differentiation is emphasized. The authors discuss the management of subependymal and (trans)mesencephalic arteries during endovascular neuro-intervention illustrative cases.

Cerebral Angiography↗
PubMed1992

Multiple cerebral arteriovenous shunts in children: report of 13 cases.

The authors present a series of 13 multiple arteriovenous malformations (MAVMs) in the pediatric population (16.9% of their overall series of brain AVMs in this group). Two types of MAVMs can be distinguished: congenital and acquired. Congenital MAVMs may be of the nidus or fistula type. They may be uni- or bilateral, placed in one or several cerebral lobes, separated or close one to another, or even systematized (Wiburn-Mason syndrome). The symptoms created by these MAVMs are the same as those encountered in the presence of other AVMs, with hemorrhage as revealing symptom in 31% of patients. The responsibility of one particular nidus in the onset of clinical signs is often difficult to determine. From an angioarchitectural point of view, it seems that venous drainage changes are mainly responsible for the symptomatology. The natural history of these MAVMs is difficult to assess; spontaneous regression has been noted in 15% of cases. Acquired cerebral MAVMs can be due to angiogenesis ("sprouting" or "non-sprouting") around a true AVM because of previous hemorrhage or ischemia, or to pial shunts associated with dural arteriovenous malformations. The treatment of MAVMs is difficult. Embolization seems to the authors the best therapeutic modality available, as surgery or radiosurgery are often unable to treat these multifocal lesions. Anatomical cure is rarely obtained; the therapeutic strategy has to be targeted on the symptomatic lesions.

Adolescent↗
PubMed1991

Epikeratoplasty for keratoglobus associated with blue sclera.

Patients with keratoglobus and blue sclera as part of a generalized connective tissue disorder are at a high risk of developing corneal perforations either spontaneously or after mild trauma. Six patients (6 eyes) between the ages of 2 and 16 years of age (mean, 7.5 years) with keratoglobus, blue sclera, hypermobile joints, and consanguineous parents were treated by epikeratoplasty, using commercially prepared 12.5-mm lenticules. Surgery was performed for tectonic support and/or visual improvement and was successful in five of six patients with a follow-up period of 11 to 27 months (mean, 21 months). One lenticule was removed because the epithelium did not heal. Peripheral interface opacities occurred in three patients.

Adolescent↗
PubMed1990

Posterior fossa arteriovenous malformations. Angioarchitecture in relation to their hemorrhagic episodes.

Classically, posterior fossa arteriovenous malformations (PF-AVMs) have been considered as lesions with high tendency to bleed. However, careful analysis of clinical and autopsy data from the literature demonstrate that in fact the incidence of hemorrhage is similar in infratentorial and supratentorial locations. The clinical perception that most of the diagnosed PF-AVMs had bled does not mean that they have a high risk of hemorrhage. It suggests that bleeding is the dominant way of expression, since other symptoms are uncommon. Furthermore, angioarchitectural analysis is similar in supra- an infratentorial locations. The causes of hemorrhage are probably related to venous anatomic and hemodynamic changes or associated aneurysms as in other intracranial AVMs.

Adolescent↗
PubMed1990

Venous anomalies and abnormalities of the posterior fossa.

The authors report a series of 16 patients with venous anomalies or abnormalities of the posterior fossa studied by angiography, CT and/or MRI. We believe that so-called venous angiomas are extreme anatomic variants that drain normal territories, and we prefer to call them developmental venous anomalies (DVAs). Posterior fossa DVAs, like the supratentorial ones are classified according to their drainage into deep and superficial types. They are exclusively located in the cerebellum or tectum. In 4 cases DVA was an incidental finding; in 3 an associated cerebral venous malformation (CVM) was found and felt to be the cause of the symptoms; and only in one (with trigeminal pain) was a link between both suspected. Cavernous venous malformations (CVMs) were found in frequent association with DVA (27%). Four cases were single and 2 multiple. Five CVMs were located in the brain stem and 3 in the cerebellum. The clinical and radiological files were reviewed and a direct relationship between symptoms and localization was found in all patients with CVM. In 2 cases venous dysplasia was found: 1 Sturge-Weber and 1 first branchial arch syndrome. Both posterior fossa venous abnormalities were incidental findings.

Adolescent↗
PubMed1990

Embolisation of the ophthalmic artery branches distal to its visual supply.

A study of the embryology and the anatomy of the ophthalmic artery shows that the branches to the important sensory structures arise proximal to the second intraorbital segment of the vessel. Damage to vision will be avoided if embolisation is restricted to vessels anterior to this "safety point", which is easily recognised on an angiogram. The ideal point of injection of emboli is even more distal and varies with the extent of the lesion and the material used. Three cases are described with vascular lesions supplied by the ophthalmic artery and embolised with Histoacryl.

Adult↗
PubMed1989

Effects of fusidic acid on staphylococcal keratitis.

We treated 20 consecutive patients suffering from staphylococcal keratitis with topical fusidic acid 1% suspension in a carbomer gel. Fifteen (79%) of the isolated Staphylococcus epidermidis strains were resistant to methicillin, but all were sensitive to fusidic acid by in-vitro testing. The keratitis showed evidence of healing in 17 (85%) of the 20 patients. The healing times ranged between 5 and 21 days (mean 10.5 days). In this open clinical trial fusidic acid proved to be a safe and effective antibiotic for the treatment of staphylococcal keratitis.

Adolescent↗
PubMed1984

[Value and indications for ultrasonographic determination of fetal sex].

From the end of the first trimester of pregnancy it is possible to recognize the sex of the fetus. The percentage with which this can be done rises progressively with the age of the fetus (from 29% at 18 weeks to 72% at 24 weeks), and with the experience of the operator. Errors are few; about between 1 and 2%. The number of errors in the ability to decide the sex is independent of which sex the fetus is. The body measurements show a difference between the made and the female fetuses which is statistically significant from the 20th week onwards. Growth tables which are specific for each sex can be made.

Female↗
PubMed1982

Effect of hyperventilation and starvation on rat lung mechanics and surfactant.

We studied the effects of hyperventilation and starvation on rat lung mechanics and surfactant. We hyperventilated lungs by excising and ventilating them at 3 times the normal tidal volume. Three days starvation reduced the alveolar pool of disaturated phosphatidyl choline by about 20% but did not significantly reduce the functional residual capacity. Air and saline deflation pressure-volume curves were performed in 4 groups: control lungs, lungs from starved rats, hyperventilated lungs, and hyperventilated lungs from starved rats. The area under each curve was calculated; this indicated the relative position of the curve in the pressure-volume diagram. We found that starvation did not change recoil, that hyperventilation increased surface recoil, and that combined starvation and hyperventilation increased it even more. We conclude that hyperventilation-induced dysfunction of surfactant is greater when the alveolar pool of surfactant is reduced by starvation. This effect might also occur clinically in the intensive care setting.

Air Pressure↗
PubMed1982

Single dose treatment with praziquantel (Cesol R, EmBay 8440) of human cestodiasis caused by Diphyllobothrium pacificum.

Diphyllobothrium pacificum, a large tapeworm of seals, is often found as an accidental parasite of man in Perú. The main symptoms is causes are abdominal pain, meteorismus and flatulence, and diarrhea. We report the results of 32 single-dose (10 mg/kg weight) treatments with Praziquantel (Cesol R, EmBay 8440) in 31 patients. One of these patients was shown to be cured but presented a reinfection 270 days later, and required retreatment. Praziquantel was effective in all cases. All patients were clinically cured. No ova were found in stool examinations at 30, 60, and 90 days after treatment, while pretreatment stools were positive for ova with all the techniques used. The antiparasitic effect was evident in 11 cases which segments of the tapeworm were eliminated within the first 3 days of treatment: the fragments were all partially digested or autolysed. A treatment scheme incorporating a purge may be best, to recover the parasite in its entirety and thus ascertain cure with no repeated controls.

Adolescent↗