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Biomedical subjects

P Ramirez

Publications and source records attributed to P Ramirez.

At least 91 records · Page 5Linked to original sources
PubMed1998

Visual input effect on EMG activity of sternocleidomastoid and masseter muscles in healthy subjects and in patients with myogenic cranio-cervical-mandibular dysfunction.

This study was conducted in order to determine the input visual effect on electromyographic (EMG) activity of the sternocleidomastoid and masseter muscles in the supine and lateral decubitus positions. The study was performed on 22 patients with myogenic cranio-cervical-mandibular dysfunction (CMD) and 18 healthy subjects. EMG activity at rest and during swallowing of saliva and maximal voluntary clenching was recorded in the supine and lateral decubitus positions in the following conditions: 1. with eyes open; and 2. with eyes closed after 5 minutes in a dark room. A significant decrease of EMG activity at rest with closed eyes in both groups was observed in the sternocleidomastoid (lateral decubitus position) and in the masseter muscle (supine position). During swallowing of saliva a significant decrease of EMG activity with closed eyes was observed only in the sternocleidomastoid muscle (lateral decubitus position) in healthy subjects. During maximal voluntary clenching any significant differences were observed upon variation in the visual input. The significant change in EMG activity, mainly observed at rest, suggests that the visual input effect is weak. The absence of a significant change in EMG activity during maximal voluntary clenching upon variation in the visual input could be clinically relevant in patients with myogenic CMD who habitually brux.

Adolescent↗
PubMed1997

Long-term results of liver transplantation in familial amyloidotic polyneuropathy type I.

BACKGROUND: The aim of this article is to report our experience regarding the survival and the evolution of polyneuropathy of the extremities and autonomic dysfunction in 18 liver transplant patients with familial amyloidotic polyneuropathy type I after a mean follow-up of more than 2.5 years for 13 patients. METHODS: The actuarial survival rate of the 18 patients is 72.2% and 60.1%, respectively, at 12 and 58 months. RESULTS: In all the patients we noted clinical improvement of the polyneuropathy of the extremities and autonomic dysfunction during the first 6 months after transplant. The clinical data due to autonomic nervous system involvement showed an earlier improvement than those due to nervous motor involvement. CONCLUSIONS: In conclusion, our results suggest that liver transplant may be useful in the treatment of certain cases of familial amyloidotic polyneuropathy to stop the neurological deterioration of the patients and to avoid the fatal end of the disease.

Adult↗
PubMed1997

Variability of geographically distinct isolates of maize rayado fino virus in Latin America.

We have examined the molecular epidemiology of the leafhopper-borne maize rayado fino virus (MRFV) in Latin America. The coat protein gene and 3' non-translated region of 14 isolates of MRFV collected from Latin America and the United States were sequenced and phylogenetic relationships examined. The nucleotide sequence revealed remarkable conservation, with a sequence similarity of 88-99%. Phylogenetic analysis of sequence data obtained from a 633 bp fragment showed that MRFV has diverged into three main clusters, i.e. the geographically distinct northern and southern isolates and the Colombian isolates. Significant differences between the isolates collected from Colombia, previously named maize rayado colombiana virus, based upon differences in symptomatology and serological relationships to MRFV, and the other MRFV isolates, provides additional evidence supporting its designation as a unique strain of MRFV.

Amino Acid Sequence↗
PubMed1997

Blood clearance of 99mTc-trimethyl-Br-IDA discriminates between different degrees of severe liver ischaemia--reperfusion injury in the rat.

The kinetics of 99mTc-Trimethyl-Br-IDA blood clearance was analysed in the rat 24 h after warm ischaemia and reperfusion of the liver. There were changes in the elimination of 99mTc-Trimethyl-Br-IDA depending on the length of the ischaemic period and the dose given. Statistically significant differences were found between the various periods of ischaemia when higher doses of the radionuclide were utilised. At lower doses, the clearance was not capable to discriminate between control rats and rats submitted to 45 min of ischaemia, but it did discriminate more severe degrees of ischaemic liver injury. Instead, galactose elimination capacity discriminated between ischaemic and control rats, but not between 45 and 90 min or between 90 and 120 min of ischaemia. Alanine aminotransferase was able to discriminate between control and ischaemic rats and between 45 and 90 min of ischaemia, but not between 90 and 120 min of ischaemia. The response of 99mTc-Trimethyl-Br-IDA clearance under extreme conditions of ischaemia and reperfusion is consistent and opens a possible window for the application of this test in the quantification of liver function in severely damaged livers and in decision making and prognosis in liver disease.

Alanine Transaminase↗
PubMed1996

Serum ionized magnesium monitoring during orthotopic liver transplantation.

During orthotopic liver transplantation (OLT) citrate accumulates and magnesium can be chelated, which can lead to ionized hypomagnesemia and cardiovascular dysfunction. Our aim was to study the serum ionized magnesium (Me2+) evolution and establish its relation to serum total Mg and citrate levels during OLT. We studied 58 adult patients undergoing OLT. The serum Me2+ level dropped significantly at the end of the preanhepatic phase, and remained low until the end of the procedure. Furthermore, the Me2+ levels remained below the range of reference from the beginning of the anhepatic phase onward. There was an inverse correlation between Me2+ and citrate for all patients. Me2+, like ionized calcium (Ca2+), is chelated by citrate and its evolution is a mirror image of that of citrate. In our patients, we did not observe any significant dysrhythmias that could be directly attributed to ionized hypomagnesemia. In conclusion, low preoperative levels, together with the massive transfusion of blood products and the increase in renal losses, cause progressive ionized hypomagnesemia in OLT patients. We propose that it he routinely monitored and treated accordingly, as is already done with Ca2+.

Adolescent↗
PubMed1996

Genotoxic effects of bistratene A on human lymphocytes.

Bistratene A, a toxin isolated from the colonial ascidian Lissoclinum bistratum causes a decrease in mitotic index and retardation of lymphocyte proliferation kinetics when it is added at 48 h to 72-h human lymphocyte cultures. In the same cultures, the incidence of sister chromatid exchanges was not altered by this compound. We also observed an increase in the number of polyploid cells in the cultures, and alterations of the beta-tubulin organization by immunocytochemistry with an antibody against beta-tubulin. Bistratene A induces DNA damage in a dose-dependent fashion in leukocytes, as measured by the alkaline single cell gel electrophoresis assay. These results show that bistratene A interferes with microtubule assembly, is cytotoxic and cytostatic, and that it causes DNA damage.

Acetamides↗
PubMed1996

Effects of cold ischemia time on the graft after orthotopic liver transplantation. A bile cytological study.

We conducted a daily analysis of bile cellularity in 16 orthotopic liver transplant patients fitted with a T-tube, and correlated the cytological parameters (number of cells per slide, and percentage of difference cell types) with the duration of cold ischemia time (CIT). Two groups were established: one comprised patients whose CIT was less than 7 hr (CIT averaged 345 min) and the other comprised patients with a CIT of more than 7 hr (CIT averaged 505 min). The control group consisted of 15 patients who had received cholecystectomy for biliary lithiasis and were fitted with a T-tube. All 3 groups showed the highest cell density on the 1st postoperative day (control: 53.3 +/- 15.5 cells/slide; short ischemia: 70 +/0 21.4 cells/slide; long ischemia: 158.8 +/- 53.2 cells/slide), which steadily ischemia group showed a higher cell density than did the control group for the first 2 days, although this was not significant. The long ischemia group showed the highest cell density, although only significantly for the first 2 days when compared with the controls, and basically at the expense of a increase in ductal epithelial cells. Our results show that prolonged cold ischemia causes an increase in bile cell density at the expense of ductal epithelial cells: the longer the preservation time, the greater the increase.

Adolescent↗
PubMed1996

Influence of abdominal incision on the formation of postoperative peritoneal adhesions: an experimental study in rats.

OBJECTIVE: To see if the three most commonly used abdominal incisions were associated with the development of postoperative peritoneal adhesions. DESIGN: Prospective experimental study. SETTING: University hospital, Spain. SUBJECTS: 30 Wistar rats. INTERVENTIONS: Three groups each of 10 rats underwent suprainfraumbilical midline laparotomy, right subcostal laparotomy or infraumbilical right transrectal laparotomy. MAIN OUTCOME MEASURES: The animals were killed after 30 days and adhesions quantified according to a special designed score which assessed the number of adhesions, their site, vascularisation, thickness, and strength. RESULTS: The transrectal incision was associated with most adhesions (median: 9.3, interquartile 7-10), followed by subcostal laparotomy (5.5, 4-6.7), and midline laparotomy (2.0, 0-7). CONCLUSIONS: Infraumbilical incisions away from the midline are more traumatic, damage more of the peritoneum, and are more likely to come into contact with the omentum, peritoneal fat, bowel loops, and pelvic contents, thereby predisposing to the formation of peritoneal adhesions.

Animals↗
PubMed1995

Clinical improvement after liver transplantation for type I familial amyloid polyneuropathy.

Long-term results of 13 liver transplantations in patients with a previous diagnosis of type I familial amyloid polyneuropathy (FAP) are presented. The diagnosis of type I FAP was based on the presence of a biochemical marker in the plasma (TTR-Met-30 in 11 patients, TTR-Ala-71 in two). Maximum follow-up is 28 months and the survival rate stands at 11 of 13 patients. Two patients died from sepsis at 2 and 6 months. TTR disappeared from plasma in all cases. Neurological status improved in all eight patients undergoing transplantation more than 6 months previously, although electromyographic studies showed a slight improvement only in the six with follow-up of more than 1 year. All 13 patients showed a hyperdynamic haemodynamic pattern with a high incidence (four patients) of the use of venovenous bypass due to haemodynamic intolerance. Two patients also received transplants by the 'piggy-back' technique. In conclusion, liver transplantation may be useful in the treatment of certain patients with FAP to halt and improve the neurological consequences of the disease.

Adult↗
PubMed1995

Significance of prenatal diagnosis of umbilical cord cyst in a fetus with trisomy 18.

An umbilical cord cyst was detected in a fetus who underwent ultrasonography at 38 weeks' gestation for clinical suspicion of intrauterine growth retardation. Such an association should alert the clinician to the possibility of aneuploidy, thus guiding clinical management. This case represents the second report of a cystic umbilical lesion in a fetus with trisomy 18.

Adult↗
PubMed1995

Haemoglobin saturation in the rat liver after ischaemia and reperfusion: study using a laser photometry technique and correlation with changes in liver tissue blood flow.

Tissue oxygenation depends on the volume of oxygen consumed by the tissue and the volume of oxygen supply. This is particularly important in the liver after ischaemia and reperfusion, due to the relatively low oxygen saturation of the portal blood flow, the main source of oxygen to the liver. In this study we established a correlation between the postischaemic liver blood flow and tissue haemoglobin saturation, measured by laser Doppler flowmetry and laser surface photometry, with the purpose of investigating the possible role of a postischaemic imbalance of oxygen delivery/uptake in reperfusion injury. The experimental procedure consisted of the temporary interruption of blood flow to the left lateral and medial lobes of the rat liver in vivo, and subsequent reperfusion after defined periods, recording the postischaemic liver blood flow and liver oxyhaemoglobin saturation. Changes were found in the postischaemic liver blood flow and haemoglobin saturation in all the groups when compared to control values, showing a correlation between the length of the period of ischaemia and the magnitude of the alteration in the reperfusion blood flow and oxygenation. These alterations may be considered as a prolongation of the metabolic condition of ischaemia and may be part of an additional tissue damage upon reperfusion.

Animals↗
PubMed1994

Ventricular function during liver reperfusion in hepatic transplantation. A transesophageal echocardiographic study.

Postreperfusion syndrome (PRS) is the most dramatic and acute hemodynamic alteration that occurs in OLT. Our aim was to determine heart function by hemodynamic monitoring and transesophageal echocardiography during PRS. We studied 24 nonconsecutive patients allocated to 2 groups: group A (n = 8), patients with PRS, and group B (n = 16), patients without PRS. Usual hemodynamic data were obtained simultaneously with transesophageal echocardiography recording of the left ventricular imaging in 4 different stages: after induction of anesthesia, 5 min before the end of the anhepatic phase, between 2 and 5 min after reperfusion, and 5 min after graft reperfusion. The hemodynamic and echocardiographic findings during reperfusion were (group A vs. group B patients): mean arterial pressure, 50.0 +/- 15.2 vs. 74.7 +/- 13.9 mmHg (P < 0.01); pulmonary capillary wedge pressure, 12.7 +/- 6.1 vs. 13.9 +/- 5.7 mmHg (NS); left ventricular ejection fraction, 79.6 +/- 9.3 vs. 83.4 +/- 9.4% (NS); left ventricular end diastolic volume index, 35.5 +/- 12.7 vs. 54.7 +/- 21.3 ml/m2 (P < 0.05); and stroke volume index, 27.9 +/- 8.9 vs. 45.5 +/- 15.9 ml/m2 (P < 0.01). There was a mild decrease in left ventricular compliance in group A. We found no alteration in left ventricular function that can justify PRS. The hemodynamic changes during PRS seemed to be caused by an insufficient increase in preload after unclamping.

Diastole↗