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H Alvarez

Publications and source records attributed to H Alvarez.

89 records · Page 5Linked to original sources
PubMedDate not supplied

Pathology of the trophoblast and fetal vessels of the placenta in maternal diabetes mellitus.

The morphologic characteristics of the chorial villi from normal full-term placentas and from placentas of different clinical types of diabetic women were studied. The latter showed early maturation of the trophoblast, higher percentage of villi with stromal edema, and higher percentage of vessels of the villous trunks with lesions causing partial or total obstruction of the vascular lumen. The fact that the diabetic patients were treated suggests that the metabolic correction of diabetes mellitus prevents the occurrence or development of the multiple disturbances which the disease produces in the evolution of human pregnancy.

Birth Weight↗
PubMedDate not supplied

[Normal and pathological ultrasonography of the fetal brain].

Advanced ultrasonic technology enabled the bidimensional imaging of fetal brain throughout pregnancy. The number of visible structures increases with gestational age. In order to certify the described items they were compared to similar anatomical sections available from brain specimens or an atlas of anatomy. Real-time as well as automatic compound scanning machines were used to obtain echographic images of fetal brain anatomy in utero. Many different scans were collected along three orthogonal directions: every 2 mm, with the automated compound scan and as close from each other as possible with the linear array real-time scanner. The material included 59 normal fetuses between the 15th and 40th week of gestation. Eight typical sections are made but the only structures identified are those being visible on every section obtained at the same level. Brain structures such as grey and white matter, nuclei, vessels and ventricles have different sonic properties. They are subsequently distinguishable on the ultrasonic image if the equipment is capable of detecting and showing such differences. Grey matter is more echogenic than white, choroid plexuses are very reflective as are vessel walls which also pulsate. Four horizontal sections are described in detail (Figs. 2-7). The coronal planes are demonstrated at three different levels (Figs. 8-12) and the sagittal plane is represented by Fig. 13. Thirty five structures were identified (Table 2). In the second section some brain and skull anomalies are briefly described. The principal signs of the abnormalities and possible encountered variations are listed such as cranial defects in anencephaly, acrania, encephalocele, iniencephaly; the anomaly of size and shape of head and ventricle, as in hydrocephaly and microcephaly, cystic-like- and solid-tumor lesions and Dandy Walker syndrome and hydranencephaly. Attention is drawn to possible artifacts and pitfalls in the differential diagnosis between similar looking pictures. Examples are given such as noise in the near field, occurring more often in sectorscan machines, inadequate orientation of scan plane producing asymetrical display of the hemisphere and the Sylvian fissure described as if it was the lateral ventricle wall. Anomalies can also be confused such as exencephaly, anencephaly, iniencephaly, encephalocele. An excellent knowledge of normal brain anatomy and pathology, together with excellent equipment and a careful scrutiny of the echograms are required qualities for fetal brain examination.

Anencephaly↗
PubMedDate not supplied

Critical closing pressure in the fetal vessel of the human placenta in vitro. II. Compared effects of a beta adrenergic substance, Salbutamol, on the critical closing pressure and vascular resistance.

Salbutamol effects upon the fetal vessels of the human placenta were studied in vitro, comparing the changes induced upon the critical closing pressure (CCP) and viscous resistance (R). Four normal full-term placentas were used. In each of them, 4 cotyledonary areas were perfused, thus obtaining a total of 16 measurements for the observation of spontaneous variations (blank), by perfusion with Krebs solution, and the same amount for the variations due to Salbutamol. The concentration used was 10 microgram/ml, with a 4.25 ml/min flow. The relative effect of Salbutamol upon CCP was its decrease--30.4% against a relative spontaneous variation of --3.6%. The mean relative effect upon R was much lower, --9.4%. against a mean relative spontaneous variation of + 3.3%. The advantages of using CCP instead of R as a parameter of vascular contractility are discussed. Furthermore, Salbutamol is suggested to be useful in improving fetal placental circulation.

Albuterol↗
PubMedDate not supplied

Total water content in different areas of the human term placenta.

The authors study the total water content in two different areas (parabasal and subchorial), in 40 normal, full-term placentas. The water content is found to be different in these two areas. As an average, it is 0.90% higher in the parabasal area. This difference persists even after washing off the fetal placental blood by perfusión with saline. The difference in the total water content between both areas, which is added to other differences previously demonstrated, must be related to a different functional role of the placental areas.

Female↗
PubMedDate not supplied

Spontaneous contractility of human placental vessels in vitro axipetal and isometric recording.

In vitro contractility of isolated cylindrical segments of chorial arteries and veins from 40 human term placentas was studied. Contractility was recorded by an isometrical and axipetal method. Spontaneous contractility was observed in 75% of the arteries and in 45% of veins. In both types of vessels, contractility was similar and characterized by development of tonic circumferential tension, between 100 and 200 mg/mm. Clonic activity consisting of rhythmic contractions with an average frequency between 0.7 and 0.9/min and an average intensity of 5--40 mg/min was superimposed. Vasoconstrictor drugs (PGF2 alpha, histamine and adrenaline) increase tonic tension without modifying the frequency of clonic activity. It is suggested that spontaneous contractility may be the expression of myogenic excitability related to the regulation of fetal placental blood flow.

Arteries↗
PubMedDate not supplied

Pseudoaneurysms within ruptured intracranial arteriovenous malformations: diagnosis and early endovascular management.

PURPOSE: To draw attention to pseudoaneurysms within ruptured arteriovenous malformations and to consider their diagnostic and therapeutic features, including pitfalls and precautions needed for safe embolization. METHODS: Radiologic and clinical charts of 189 patients who bled from intracranial arteriovenous malformations were retrospectively reviewed. RESULTS: Fifteen of the 189 (8%) were found to have pseudoaneurysms. Nine of the pseudoaneurysms were arterial, six were venous. In the early period following hemorrhage, nine patients were treated conservatively. The other six were treated with surgery (one case) or embolization (five cases) because urgent intervention was required. The clinical outcome for both conservative and interventional groups was generally favorable, but one patient in the conservative group died of a rebleed. In the patients who underwent embolization, the fragile nature of the pseudoaneurysm made it necessary to first embolize the artery feeding it. Embolization with particles was considered hazardous. Instead, free-flow (nonwedged) N-butyl-cyanoacrylate embolization proved safe and effective in treating both the pseudoaneurysms and arteriovenous malformations in these cases. CONCLUSIONS: This study highlights the importance of recognizing pseudoaneurysms in such patients and the importance of using free-flow liquid adhesive material on the artery feeding the pseudoaneurysm if embolization is required.

Adolescent↗