Biomedical subjects

G Marrero

Publications and source records attributed to G Marrero.

9 recordsLinked to original sources

PubMed2006

Perinatal/postnatal study of D-003, a mixture of long-chain fatty acids, in rats.

D-003 is a mixture of long-chain fatty acids isolated and purified from sugar cane wax with cholesterol-lowering and antiplatelet effects. In order to further characterize the developmental toxicity during the treatment period from late gestation up to weaning of the offspring, pregnant females received 0 (control), 500, and 1,000 mg/kg/day D-003 daily by oral gavage beginning at day 15 of pregnancy and through gestation until day 21 postpartum. Maternal clinical signs, body weight, and food intake were measured at regular intervals during gestation and lactation. Live pups were weighed, sexed, and examined for developmental signs. One female and male of each litter were randomly selected to evaluate the reproductive potential. There were no spontaneous or dose-related maternal deaths during the course of this study. The general health and behavioral condition of offspring was good in all groups. No significant differences among groups were found in comparisons of litter size, survival through the weaning period, sex ratio, and male and female weights. This peri- and postnatal study conducted with D-003 in rats indicated that treatment of the dam during late gestation and lactation did not show adversely effects on reproductive performance or fetal development over two generations.

Animals↗

PubMed2001

Deaggregation is an integral component of the response of platelets to ADP in vitro: kinetic studies of literature and original data.

Adenosine diphosphate (ADP) is recognized as an important mediator of platelet aggregation. Transient aggregation at low (< or =1 microM), and sustained aggregation at higher ADP concentrations are consistently observed. Dissociation of platelet aggregates has been described and may explain the reversible component of the aggregation response. We hypothesized that the net aggregation response to ADP in vitro results from the concurrent activation of two opposing processes, aggregation and deaggregation. Different purinergic receptor subtypes may mediate these effects. To test this hypothesis and its generalizability, we performed a kinetic analysis of representative published ADP-induced aggregation responses supplemented with original data from our laboratory. A four-compartment kinetic model was used to estimate k(3), a rate constant of deaggregation. Two model-independent parameters, the magnitude of the aggregation response (DeltaOD) and the time to reach maximal aggregation (t(peak)) were also assessed. Greater sustained aggregation at higher ADP concentrations was consistently associated with increased DeltaOD and t(peak) but decreased k(3) values. These relationships were independent of type of platelet preparation or experimental conditions and not due to ADP receptor desensitization. Conversely, blockade of the P2Y(12) receptor subtype (ticlopidine, clopidogrel or 2-MeS-AMP) decreased DeltaOD and t(peak) but increased k(3) values. This supports the presence of active deaggregation which is decelerated by activation of the P2Y(12) receptor subtype.

Adenosine Diphosphate↗

PubMed2001

Lasers in dermatology: a review.

The revolution in laser technology has had a significant impact on medicine in general and dermatology in particular and has piqued the interest of physicians, the lay public, and the media. Advances in laser therapy have dramatically improved the clinicians' ability to treat cosmetic and noncosmetic skin lesions safely and effectively. The number and variety of skin problems amenable to laser treatment continues to grow. We will provide a review of the major cosmetic and therapeutic applications of laser therapy.

Hair Removal↗

PubMed1997

[Effect of diltiazem on cold-induced left ventricular dysfunction in patients with systemic sclerosis].

Patients with systemic sclerosis (SS) have cardiac dysfunction induced by cold exposure. We and others have demonstrated this finding after corporal chilling, suggesting a "coronary Raynaud phenomenon" mediated by intermittent vascular spasm. In this study we evaluated the effect of diltiazem (DTZ) in cardiac dysfunction induced by cold test in patients with SS without clinical evidence of heart disease. Twelve patients with SS were studied. One patient was excluded because he did not fulfill the prescribed treatment. Eleven patients (age of 49.9 +/- 3.8 years and illness duration of 9.3 +/- 4.8 years) were included. Gated equilibrium radionuclide ventriculography was recorded after red blood cells were labeled in vivo using an intravenous injection of stannous pirophosphate followed by 20 mc of 99 Tc (gamma camera with electrocardiographic R wave gating was used). Left ventricular injection fraction (LVEF) was calculated using computer analysis and wall motion abnormalities by visual interpretation. Patients were cooled using a thermic blanket set at 5 degrees centigrade. They were evaluated before and after a period of cooling. After corporal chilling LVEF decreased more than 10% in all of them. DTZ 270 mg a day was administered to the same patients during 48 hs. Basal and cold LVEF were repeated in all patients. The results with and without DTZ were compared by Student's t Test. The basal LVEF with and without DTZ was not different (64.8 +/- 2.6 and 63.1 +/- 1.8). After corporal chilling LVEF decreased (64.8 +/- 2.6 to 54.8 +/- 2.5 p < 0.00001) and reversible abnormalities in wall motion were noticed in patients without DTZ. When they received DTZ neither difference in LVEF (63.1 +/- 1.8 to 62.1 +/- 2.4) nor wall motion abnormalities were observed. We compared the LVEF after chilling (62.1 +/- 2.4 and 54.8 +/- 2.5) and we found an important difference with the use of DTZ (p < 0.005). It can be concluded that in patients with SS and no overt heart disease, DTZ prevents the early cardiac dysfunction induced by cold test. Probably this drug blunts the coronary spasm induced by cold test in this group of patients.

Body Temperature↗

PubMed1995

[Cold-induced cardiac abnormalities in systemic sclerosis].

Cardiac abnormalities are frequent in patients with systemic sclerosis (SS). These abnormalities have been demonstrated in over 80% of patients with SS and there are some clues that suggest that an intermittent vascular spasm (i.e. coronary Raynaud's phenomenon) is one of the causes of myocardial dysfunction in this group of patients. The aim of this prospective study was to evaluate the ventricular performance and regional wall motion during exposure to cold in patients with SS and Raynaud's phenomenon without overt cardiac disease. Twenty-four patients and 10 normal volunteers underwent radionuclide ventriculograms (RV). In each subject the RV was done thrice: basal, 20 minutes after chilling with thermic blanket and post reheating. The left ventricular ejection fraction (LVEF) decreased during the cold test (p = 0.03) with reversible abnormalities in wall motion. Basal Right Ventricular Ejection Fraction (RVEF) was lower than that of normal subjects (p = 0.02) and decreased during the cold test (p = 0.04). Therefore, we were able to demonstrate an early cardiac dysfunction associated with impaired wall motion after corporal chilling. These findings suggest that coronary spasm in SS would be an early and frequent phenomenon that would precede the development of symptomatic cardiac disease in some patients with this illness.

Adult↗

PubMed1992

Effectiveness of different endodontic files for preparing curved root canals: a scanning electron microscopic study.

In this study, the effect of using four endodontic files from different manufacturers on the final shape of 80 prepared curved root canals of extracted single-rooted teeth were comparatively analyzed with scanning electron microscopy. The instruments tested were Tri-files, Flex-R files, Flexofiles and conventional K-type files. All files were used with in and out linear movements with a circumferential motion starting with a size 15 file. Final preparation of the apical thirds was performed with a size 30 file. Shaping effectiveness of the tested files was qualitatively evaluated in terms of respect for conservation of the apical constriction and the presence or absence of ledging, specially in the apical third of the root canals. A well-centered and tapered preparation without apical transportation or ledging was detected when Tri-file or Flex-R files were used. Conversely, the use of Flexofile or conventional K-type files resulted in frequent alteration of the initial pattern of the root canals, showing an hour-glass preparation with alteration of the apical constriction and ledge formations.

Dental Cavity Preparation↗

PubMed1991

Avoiding paraplegia during anterior spinal surgery. The role of somatosensory evoked potential monitoring with temporary occlusion of segmental spinal arteries.

Three patients paraplegic following anterior spinal fusion for congenital kyphoscoliosis were noted to have complete somatosensory evoked potential signal loss shortly after segmental arterial ligations at the apex of their respective kyphosis. This has prompted us to use temporary segmental arterial occlusion with somatosensory evoked potential monitoring prior to ligation during anterior spinal fusion. As a result, we have noted seven additional cases, out of a total of 44 cases monitored in this fashion, in which complete loss of somatosensory evoked potential signals, reversible by release of vascular clips, has occurred. For each of these additional cases the critical segmental arteries were identified and were not ligated, usually resulting in some modifications in the planned surgical procedure, and the patients remained neurologically intact. We recommend temporary segmental arterial occlusion with somatosensory evoked potential monitoring during thoracolumbar anterior spinal fusion to potentially avert ischemic neurologic injury. Based on published data and the experience described herein, this technique should be especially important in anterior spinal fusion for congenital kyphoscoliosis.

Adolescent↗

PubMed1988

Results of 21 Wagner limb lengthenings in 20 patients.

Roentgenograms and charts were reviewed on 20 patients (average age: 13.2 years) who had 21 Wagner limb lengthenings since 1975. Lengthenings included 15 femora (six acquired, eight congenital, and one fibrous dysplasia), four tibiae, and two humeri (one acquired and one congenital). Average femoral lengthening was 6.6 cm; tibial, 5.9 cm; and humeral, 9.7 cm. Lengthening of femora with congenital shortening (6.5 cm) was nearly the same as femora with acquired shortening (6.8 cm), and 85% of all lengthenings were greater than 5 cm. Humeri were lengthened more than 50%. Seventy-two percent of patients were in the 50th percentile or less of stature; 61% were in the 15th percentile or less of stature. Seventy-five percent had complications, with 65% having more than one major complication: pin tract and superficial infections in 40%; deep infections in 20%. All infections were in femoral lengthenings. Nonunion occurred in two patients (10%), and fracture after plate removal in two patients (10%). Five patients (25%) had nerve palsies, and four of these resolved without treatment. Malunion rate was 20%. Five patients developed joint contractures. Complications did not correlate with amount of lengthening but congenital deformities had a higher incidence of complication. Eleven patients required 19 additional procedures necessitated by the lengthening procedure. Wagner leg lengthening is generally recommended when amputation is only other surgical alternative and a full, complete informed consent is given to the parents and patient.

Adolescent↗

PubMedDate not supplied

Congenital pseudarthrosis of the clavicle: a review of the literature and surgical results of six cases.

This article is a retrospective review of six symptomatic patients who, when treated surgically, all healed with excision of pseudarthrosis, bone grafting, and plating. We discuss congenital pseudarthrosis of the clavicle with emphasis on etiologies, clinical presentation, differential diagnosis, and method of treatment. Our patients' chief complaints were cosmesis, pain, or shoulder deformity.

Adolescent↗