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Biomedical subjects

H Alvarez

Publications and source records attributed to H Alvarez.

At least 37 records · Page 2Linked to original sources
PubMed2000

Role of persistent amenorrhea in bone mineral metabolism of young hemodialyzed women.

BACKGROUND: Chronic renal failure in women is frequently associated with endocrine disturbances leading to menstrual disorders. However, most studies on renal osteodystrophy have not taken into account the possible role of these hormonal disturbances on the pathogenesis of bone alterations seen in these patients. In the present study, we evaluated bone mineral metabolism in a group of young hemodialyzed women with persistent amenorrhea and compared them with similar women with regular menstruation. METHODS: We studied 74 women who were further subdivided into 43 women with regular menstrual periods and 31 women with persistent amenorrhea, defined as the absence of menstrual bleeding for more than six months. In all patients, we performed a bone mineral density (BMD) analysis and simultaneously evaluated different biochemical parameters, intact parathyroid hormone (iPTH), sexual hormone determinations that included total estradiol, follicle-stimulating (FSH), and luteinizing hormone and markers of bone resorption such as the procollagen type 1 cross-linked carboxy-terminal telopeptide (ICTP). RESULTS: Serum calcium, phosphorus, and iPTH were similar in both groups. Serum alkaline phosphatase was higher in amenorrheic women. Although the total serum estradiol concentration was normal in the amenorrheic women when compared with nonuremic women, the values were significantly lower than those in regularly menstruating women. Serum FSH and ICTP values were significantly higher in the amenorrheic women. Trabecular BMD in the lumbar spine was also significantly lower in the amenorrheic women compared with regularly menstruating dialysis patients. Lumbar spine BMD and total estradiol levels correlated significantly in the amenorrheic group. CONCLUSIONS: These studies show that persistent amenorrheic young women on dialysis have lower trabecular BMD and evidence of increased bone resorption when compared with normal menstruating women on dialysis. The possible impact of these results in the natural history of the uremic osteodystrophy remains to be determined.

Adult↗
PubMed2000

Factors associated with intracranial hemorrhage in cases of cerebral arteriovenous malformation.

OBJECTIVE: The standard categorization of arteriovenous malformations (AVMs) involves the Spetzler-Martin grading system, which uses a simple analysis of size, location (superficial or deep), and the presence of deep or superficial drainage. Hemodynamic risk factors are also thought to play important roles in the pathogenesis of these lesions and to be associated with the intracranial hemorrhage (ICH) rate. The actual hemodynamic factors for AVMs cannot be easily measured, but angioarchitectural features can be assessed and used as surrogate parameters. METHODS: The AVM angioarchitectural features for 662 patients were analyzed, and their associations with ICH as a presenting sign were studied. A cross-sectional analysis was used to qualify the strength of associations among clinical features, angioarchitectural characteristics, and ICH before treatment. RESULTS: The multivariate analysis indicated that arterial stenosis and arterial ectasia were associated with lower ICH rates, whereas venous stenosis increased the rate of ICH. The presence of angiogenesis modified the effects of arterial and venous stenosis. Furthermore, the effect of venous stenosis depended on the location of the nidus. The presented data do not support a direct positive association between associated aneurysms and ICH. CONCLUSION: Certain angiographic features seem to have prognostic potential with respect to the occurrence of ICH among patients with AVMs. A discriminatory prognostic index is proposed; its relevance must be proven in a future prospective study.

Adolescent↗
PubMed2000

Cerebral arteriovenous malformations and associated aneurysms: analysis of 305 cases from a series of 662 patients.

OBJECTIVE: Spontaneous intracranial hemorrhage is the primary danger for patients with cerebral arteriovenous malformations (AVMs). Associated aneurysms are considered weak points that increase the risk of intracranial hemorrhage. Aneurysms are classified as proximal aneurysms (PROXs) or intranidal aneurysms (INs). METHODS: The present study was based on a series of 662 patients who presented with AVMs between 1985 and 1995. Its purpose was to evaluate prestated hypotheses using prospectively collected data. In 305 of these 662 patients, 372 INs and 313 PROXs were observed and analyzed with respect to their shapes, locations, and sizes. Partial targeted endovascular treatment with n-butylcyanoacrylate was performed for 450 of the 662 patients (68%) in this series, using a standard protocol. Of 450 treated patients, 181 (40%) had at least one IN and 138 (30.7%) had at least one PROX. Analysis of changes in the sizes of PROXs was based on the follow-up data for 83 treated patients, with a total of 149 PROXs. Changes in the sizes of PROXs in treated patients were analyzed with respect to PROX shapes, PROX locations, and treated AVM occlusion rates. Univariate and multivariate event data analyses were used to study factors influencing aneurysm shrinkage. False aneurysms were excluded from the series. RESULTS: Presentation with intracranial hemorrhage was not correlated with any type of aneurysm. However, INs demonstrated a higher rebleeding rate (P < 0.002) before treatment. Among 181 patients, 92.2% of INs were occluded, together with the related portions of the AVM nidi. In cases of PROXs, embolization of the cerebral AVM compartment fed by the artery with the aneurysm was a priority. During follow-up monitoring of 83 treated patients with 149 PROXs, 100% shrinkage was observed for 12 PROXs and more than 50% shrinkage was observed for 33 PROXs. The median time required for more than 50% shrinkage was 3.5 years. The shrinkage of PROXs was influenced by the degree of AVM occlusion (P = 0.027) and occurred faster for PROXs on midline structures, such as the anterior cerebral artery and the circle of Willis, compared with arteries distal to the circle of Willis (P = 0.004). No rupture of untreated PROXs was observed after partial targeted treatment of AVMs. CONCLUSION: PROXs are not primary treatment targets, compared with AVMs themselves. INs should be primary targets of endovascular therapy, because of their increased risk of rebleeding.

Adolescent↗
PubMed1999

Strongyloides stercoralis hyperinfection associated with human T cell lymphotropic virus type-1 infection in Peru.

A study was conducted in Lima, Peru to determine if patients with Strongyloides hyperinfection had human T cell lymphotropic virus type-1 (HTLV-I) infection. The study included patients with Strongyloides hyperinfection and a control group consisted of sex- and age-matched asymptomatic healthy individuals whose stools were negative for Strongyloides. A third group included patients with intestinal strongyloidiasis. Sera from each study subject were tested for HTLV-1/2I by an ELISA and Western blot. The HLTV-1 infection rates (85.7%, 18 of 21) were significantly (P < 0.001) associated with Strongyloides hyperinfection compared with the control group (4.7%, 1 of 21). The HTLV-1 rate (10%, 6 of 62) for patients with intestinal strongyloidiasis was significantly (P < 0.001) lower than patients with Strongyloides hyperinfection, but did not differ significantly (P > 0.05) from the control group. The association of HTLV-1 infection was observed among 17 of 19 patients more than 20 years of age and one of two younger patients. None had HTLV-2 infection. In conclusion, Strongyloides hyperinfection among Peruvian patients was highly associated with HTLV-1 infection.

Adult↗
PubMed1999

[Arteriovenous malformations in the jaws. The place of intravascular therapy. Apropos of 14 cases].

PURPOSE: To analyze arteriovenous malformations (AVMs) of maxillo-mandibular arcades seen in our department since 1977, and to determine adequate treatment. MATERIAL AND METHODS: Fourteen AVMs were reviewed to determine their revelation, their semiology, the treatment applied and the results that could be obtained. All these lesions were true AV shunts involving bone with or without soft tissue extension. RESULTS: Eight patients belonged to the pediatric population. Six lesions were maxillary and 8 mandibular. All lesions were revealed during or after puberty by local swelling, pain, mass effect or bruit. Hemorrhage was the most frequent (71%) symptom. Teeth instability was detected in all these patients and was origin of the bleeding. The lesions were suspected clinically and confirmed radiologically. Angiography analyzed properly the architecture of the lesion (4 arteriovenous fistulas). Embolization was the clinical treatment in all patients: particles helped to stabilize the acute situations but failed to offer stable results, necessitating complementary embolizations and/or surgery (hemimandibulectomy in 2 patients). The use of acrylic glue (Histoacryl), injected percutaneously (5 patients), or transarterially in the AVM (4 patients)) provided cure in 6 of these lesions (43%) and long term stabilization for all the other AVMs. Teeth extraction could be performed thereafter in good conditions. Antibiotics and anti-inflammatory treatment helped to stabilize the evolutive risk of these lesions. CONCLUSION: Embolization is the therapy of choice in these lesions. Appropriate use of glue offers a high rate of cure and/or clinical stabilizations and avoids unneeded surgery.

Adolescent↗
PubMed1998

Grandmothering, menopause, and the evolution of human life histories.

Long postmenopausal lifespans distinguish humans from all other primates. This pattern may have evolved with mother-child food sharing, a practice that allowed aging females to enhance their daughters' fertility, thereby increasing selection against senescence. Combined with Charnov's dimensionless assembly rules for mammalian life histories, this hypothesis also accounts for our late maturity, small size at weaning, and high fertility. It has implications for past human habitat choice and social organization and for ideas about the importance of extended learning and paternal provisioning in human evolution.

Animals↗
PubMed1998

Arteriovenous malformations of the dental arcades. The place of endovascular therapy: results in 12 cases are presented.

Twelve arteriovenous malformations of the dental arcades (AVMDAs) (seven mandibular and five maxillary) were seen in our institution between 1977 and 1997. All these lesions consisted of true arteriovenous shunts (of either nidus or fistulous type) involving the bone, with or without soft tissue extension. Haemorrhage was present in eight patients (67%); either torrential, necessitating emergency embolization, or recurrent and progressive. Teeth instability was detected in all patients and was the origin of the bleeding. All lesions were embolized. Lesions in nine patients were embolized with Polyvinyl Alcohol Particles (PVA): this helped to stabilize the situation but could not avoid recurrences in all patients, necessitating complementary embolizations and or surgery. The use of acrylic glue (N-Butyl-Cyano-Acrylate [NBCA] Histoacryl) as the embolic agent has changed the results obtained tremendously. Eight patients have been treated with NBCA (five as complementary therapy to PVA during later sessions and three at the first attempt); injection either via the transarterial route or direct transcutaneous puncture (four patients) achieved a cure in four of these lesions (34%) with stability at long-term follow-up of all the other AVMs. Embolization with glue represents the therapy of choice in these sometimes life-threatening lesions, achieving a cure if directed towards the osseous venous lakes. Surgery, often leading to facial mutilation and necessitating massive reconstruction should be avoided nowadays, at least as the initial therapy.

Adolescent↗
PubMed1997

[Ischemic cerebral vascular accident caused by vertebral artery dissection].

BACKGROUND: Strokes due to vertebral artery lesions are not yet well known in children. CASE REPORT: We report on a case of post-traumatic vertebral artery dissection responsible for ischemic stroke in a 8-year old boy. Headache, vomiting and a brief loss of consciousness were the main initial signs. Neurological examination showed a locked-in syndrome. Cerebral imaging revealed lesions in cortical cerebellar hemisphere, cerebral pedoncular and protuberance. An arteriogram performed on day 10 showed left vertebral artery occlusion at C2 levels consistent with vertebral dissection. Antiagregants treatment was given. Neurological recovery was good. Pertinent clinical data of 24 children who had strokes due to a vertebral artery dissection are analysed. CONCLUSION: Vertebral artery dissection is presently a well-known cause of childhood strokes. Benefits from anticoagulants are now established.

Aortic Dissection↗
PubMed1996

Preliminary results of embolisation of nonsurgical intracranial aneurysms with GD coils: the 1st year of their use.

We report 28 patients with nonsurgical intracranial aneurysms referred by neurosurgeons for endovascular treatment using platinum detachable coils (GDC, Target Therapeutics, Fremont, Calif., USA). Because of unfavourable anatomical features or failed hyperselective catheterisation, 4 patients were not treated. In the other 24 patients (26 aneurysms) embolisation was successful. No manufacturing defect was detected in the coils used. Complete occlusion of the sac was obtained in 22 of the 26 aneurysms (85%) regardless of their size. The glasgow outcome score was good on discharge in 20 of the 24 patients (83%). The Karnovski score at 3 months after embolisation revealed that 20 patients (83%) lead a normal life, with minor neurological signs. Morbidity related directly to treatment occurred in 2 cases (8%): a superior hemianopia due to mass effect on the optic nerve from a carotid-ophthalmic aneurysm, and hemiparesis due to an embolus. Five transient deficits lasting hours to a few days were related to proven or suspected emboli. No death occurred. Anatomical, technical and clinical data are reported; the mean cost of materials (catheters and coils) per patient and aneurysm was FF 13,500. The mean hospitalisation time was 6.5 days in the neurosurgical department with 2.8 days of intensive care.

Adult↗
PubMed1995

Nongalenic cerebral arteriovenous malformations in neonates and infants. Review of 26 consecutive cases (1982-1992).

We present 26 consecutive cases of nongalenic pial arteriovenous malformations (PAVMs) diagnosed in the neonatal period or in infancy. No diagnosis was made antenatally. Presenting symptoms in neonates were systemic cardiac manifestations (54%), seizures (31%), and hemorrhages (15%). In infants, hemorrhagic strokes and hydrodynamic disorders (external or internal hydrocephaly, macrocephaly, atrophy) both occurred in 38% of cases. Systemic cardiac manifestations and seizures were rare at that age (respectively 16% and 8%). Sixty-two percent of neonates and 31% of infants already had neurocognitive disorders (assessed by pediatric neurocognitive testing: Brunet-Leizine and Denver tests) when referred. The venous drainage and its anomalies (ectasias, stenoses, thromboses) were the main causes of symptoms. Atrophy and leukomalacic lesions occurred rapidly; they express local hydrovenous disorders and are specific to this population group. Untreated neonates and infants have a poor prognosis. Endovascular treatment, although partial and challenging in all instances, represents the treatment of choice in our series. Of the eight neonates treated, one improved to normal (12.5%), while four remained stable (50%): two neurologically normal, two with mild neurological deficit. Three (37%) died despite embolization (heart failure, multiorgan failure, postoperative death). Transient neurological complications occurred in two cases (25%): hemiparesis in one patient with a rolandic and in one with a thalamic AVM. Of the eight infants successfully embolized, one was significantly improved (12.5%) and is now neurologically normal, while five remained stable (62.5%): four neurologically normal, one with mild neurological deficit. One died between two sessions of embolization from intracerebral hemorrhage (12.5%). Hemianopsy occurred in one case (12.5%) after embolization of an occipital AVM. In one additional case in a normal child we failed to embolize the last small pial AVM of four after the three others had spontaneously thrombosed. With a minimal follow-up of 18 months and a maximum of 7 years, the review of our series shows 53% of the initial group of neonates and infants growing neurologically normal after therapeutic management in our institution; 23.5% died despite treatment, and the remaining 23.5% present minor neurological deficit. When targeted at the points of angioarchitectural weakness, embolization contributes to stabilizing a lesion. It should be undertaken rapidly to avoid loss of brain substance secondary to hemorrhage, atrophy, or leukomalacia, and to allow neurocognitive recovery and normal brain maturation. In our experience, these lesions are the most aggressive ones for the maturing brain, and the most difficult to approach technically. They represent a new therapeutic field and have their own specific anatomy and physiology.

Adolescent↗
PubMed1995

Cerebral arteriovenous malformations in children. Management of 179 consecutive cases and review of the literature.

Over the past 10 years (1982-1992), we have been actively involved in the management of 179 cerebral arteriovenous malformations (CAVMs) in children and infants. Seventy-seven were true vein of Galen malformations (VGAMs) and 102 were pial AVMs (PAVMs), i.e., developed in the subpial space. Hemorrhage occurred as the first symptom in 50% of the children with pial AVMs, but was present in none of the VGAM cases. Only 31 children were found to be unsuitable for endovascular treatment, and in 124 cases embolization was indicated as the primary treatment (104 embolization performed). Only 21 children underwent a direct surgical approach (none in the VGAM group). In the embolized group in whom treatment has been completed (n = 56), 8 children died, 39 have an anatomical cure, and 34 are clinically normal. In the group under treatment (n = 48), 16 are not normal. The problems are timing and the aims (total or partial treatment) of the therapeutic procedures. In the nonembolized group (n = 31), 8/13 of the pial lesions were operated on (no mortality, 2 patients with moderate neurological deficits). In the VGAM group 13/18 died and 4 had spontaneous thrombosis (only 1 is neurologically normal). In the nonembolized group 13 lesions have been completely excluded, but only 5 patients are neurologically normal. This fact again stresses the need for prognostic evaluation before treatment and a clear definition of the treatment aims. Analysis of a large number of published series on the management of children with AVMs (1017 cases) reveals inconsistencies that hamper proper evaluation and comparison. In our experience, endovascular treatment always seems to be the best primary treatment in both VGAMs and PAVMs. However, management of children with these lesions requires a large multidisciplinary team, which is the only way of offering the most suitable and effective treatment, the sole guarantee of a good result.

Adolescent↗
PubMed1995

Pial arteriovenous fistula in children as presenting manifestation of Rendu-Osler-Weber disease.

We present four cases of pial arteriovenous fistula (AVF) in children as the presenting manifestation of Rendu-Osler-Weber disease (ROW). The common clinical manifestations of ROW in adults, such as skin telangiectasia and mucosal haemorrhagic complications, seldom occur in children, since telangiectases develop with age. Pial AVF in ROW also conform to the usual age incidence and are therefore present in childhood. Of the four children in this series, three had multiple AVF. Two presented with central nervous system haemorrhage, one with seizures and the other with progressive neurological deficit. There were no clinical or angioarchitectural differences between the AVF associated with ROW and sporadic AVF. The diagnosis was based in all cases on the family history. Transarterial embolisation to obliterate the AVF was carried out in all patients. One patient had early rebleeding after partial embolisation of the AVF, with a fatal outcome. Three patients were cured and one asymptomatic in long-term follow up. No exhaustive search was conducted for multiorgan telangiectases, since there is no indication for treatment of asymptomatic telangiectasia in ROW. No pulmonary fistulae were found. ROW should be suspected in children with multiple pial AVF; they may be the only manifestation of the disease, since epistaxis and telangiectasia are unusual in early life.

Adolescent↗
PubMed1995

Transarterial embolization of vein of Galen aneurysmal malformation after unsuccessful stereotactic radiosurgery. Report of three cases.

The authors present three cases of vein of Galen aneurysmal malformations (VGAMs) diagnosed in infancy and submitted by the referring teams for stereotactic radiosurgery as the initial therapy (therapeutic doses ranging between 20-25 Gy and 40-50 Gy to the peak dose). After the conventional follow-up of 18-24 months, no change could be detected in the angioarchitecture of the lesions. All three cases were then referred for endovascular treatment and underwent embolization by the transarterial route using liquid adhesives (N-butyl cyanoacrylate). This resulted in complete anatomical exclusion of the lesion. Regardless of the theoretical efficiency of radiosurgery in the management of brain arteriovenous malformations, the present authors believe that transarterial embolization remains the treatment of choice in VGAMs. It offers a high rate of morphological cure and the best chances for normal neurocognitive development. The time required by radiosurgery to achieve a significant result is too long for developing and maturing brain and may not prevent the negative effects of the lesion, mainly in regard to hemo- and hydrodynamic disorders (atrophy, subcortical calcifications, etc.) created by the VGAM, thus leading to irreversible mental retardation.

Cerebral Angiography↗
PubMed1995

An assessment of cerebrospinal fluid's total creatine-kinase activity in the differential diagnosis of metabolic and organic causes of coma.

The objective of the study was to assess total cerebrospinal creatinine-kinase activity (CSF-CK) measurement in differential diagnosis of "metabolic" and organic causes of coma. The setting for the study was a tertiary care reference medical center and community general hospital. The design of the study was a series of consecutive patients with profound coma (Glasgow scale ratings between 3 and 6) as the presenting complaint to the emergency room and controls. Measurements and main results were as follows: CSF-CK was measured in 103 consecutive patients including 18 patients with metabolic causes of coma, 27 patients with organic causes of coma, 18 patients scheduled for elective orthopedic surgery with epidural anesthesia and 27 patients with compressive myelopathy and radiculopathy. CSF-CK activities were significantly different between groups (H = 29.48, p < 0.001, Kruskal-Wallis test), controls had a median of 0 mU/ml (range 0-16 mU/ml), patients with metabolic causes of coma had a median of 0 mU/ml (range 0-65 mU/ml), patients with compressive myelopathy or radiculopathy had a median of 19 mU/ml (range 0-80 mU/ml), and patients with organic causes of coma had a median of 20 mU/ml (range 0-400 mU/ml). The test sensitivity was 83% (95% confidence interval (CI 65-100%) specificity 62% (CI 43-80%) positive predictive value 60% (CI 49-79%) and negative predictive value 85% (CI 75-95%). The conclusion of the study was that the test is useful for ruling out metabolic causes of coma when CSF-CK activity is high (i.e., above 16 mU/ml).

Adult↗
PubMed1995

[Use of GDC coils in treatment of inoperable aneurysms: report of initial experiences].

The authors report on the endovascular occlusion of intracranial aneurysms with GDC coils in 8 patients. In 2 cases, the diagnosis was made because of subarachnoidal hemorrhage. Three patients complained about headache, and one patient had an oculomotor palsy. The findings were incidental in 2 cases. Angiography demonstrated an aneurysm of the internal carotid artery in 4 of the 6 females and in the 2 males (mean age 50 years) and a basilar artery aneurysm in 4 cases. The indication for endovascular treatment was established after carefully weighing the risks against those of a neurosurgical intervention. It was possible to occlude completely the aneurysm by induced electrothrombosis and to preserve the patency of the main vessel in all cases. One female (case 6) developed a hemiparesis due to embolism of a medial branch six hours after treatment. This receded completely after thrombolysis with urokinase. A second patient showed further growth of the internal carotid aneurysm on the control angiogram obtained after six months. Our initial results are encouraging. With increasing experience, endovascular treatment is expected to become the method of choice for the treatment of most inoperable cerebral aneurysms.

Adult↗
PubMed1994

Prognosis of antenatally diagnosed vein of Galen aneurysmal malformations.

In our experience of 168 consecutive cerebral arteriovenous shunts, all antenatally diagnosed lesions were vein of Galen aneurysmal malformations (VGAMs). This series consists of 18 cases of VGAMs detected by ultrasound during the third trimester of pregnancy. There were 12 normal vaginal deliveries, 5 deliveries by cesarean section, and 1 induced abortion. Sixteen newborns (94%) presented with systemic cardiac manifestations as the first clinical symptoms; 12/16 were managed effectively by digitalo-diuretic treatment, while 4 (25%) died shortly after birth from acute heart and/or multiorgan failure with extensive brain damage. Twelve babies underwent embolization via the arterial route in infancy (2 at 2 months of age). Total exclusion was obtained in 8 babies (67%, 3 with 6 months follow-up). Furthermore, 67% of the newborns managed by our team are neurologically normal (Denver and Brunet-Leizine tests). These results emphasize that the pessimism that follows antenatal discovery of these lesions and the previous assumption of a bad prognosis for VGAMs can nowadays be reviewed in the light of transarterial endovascular therapy applied according to a strict clinicoradiological protocol. Interventions in the neonatal period are rarely required. Generally, poorly timed mechanical therapy should be discouraged.

Algorithms↗
PubMed1994

Paraspinal arteriovenous shunts in children.

Arteriovenous shunts within the spinal canal and in the paraspinal region are unusual. Spinal cord and dural arteriovenous communications have been the subject of numerous reports but paraspinal shunts causing venous congestion in the spinal canal are rarer and may present special problems in diagnosis and management. We describe three children with paraspinal arteriovenous malformations, associated with overt or potential venous congestion in the spinal canal. In each case, the lesion was successfully obliterated by endovascular therapy. Embolisation with permanent occlusive agents is an effective treatment for these rare but potentially debilitating lesions.

Arteriovenous Malformations↗