Biomedical subjects

N Ramírez

Publications and source records attributed to N Ramírez.

At least 19 recordsLinked to original sources

PubMed2004

Phenotype characterization and natural history of spondylothoracic dysplasia syndrome: a series of 27 new cases.

Spondylothoracic dysplasia (STD, MIM#277300) is an autosomal recessive disorder with high prevalence in the Puerto Rican population. It is generally regarded as a lethal condition. Since Jarcho and Levin described it in 1938, it has been referred to as spondylocostal dysplasia, costovertebral dysplasia, Jarcho-Levin syndrome and STD. We have prospectively characterized 27 patients with STD by detailed physical examination, pedigree analysis, thoracic CT scans, and pulmonary function tests (PFTs). Diagnoses were established using spinal radiographs and 3-D reconstructive CT scans to demonstrate fusion of the ribs at the costo-vertebral junction with a fan-like (crab-like) configuration of the thorax. Vertebral segmentation and formation defects were seen throughout the spine with a decrease in the number of vertebral bodies. Characteristic vertebral shape consisted of a decrease in antero-posterior diameter and an increase in lateral length, giving the vertebra a sickle shape. Eight out of 18 prospectively follow patients died within the first 6 months of life, a 44% mortality rate. Cause of death was respiratory insufficiency secondary to pneumonia and pulmonary restriction. This is an important finding since the vast majority of STD syndrome patients cited in the medical literature have died in the newborn and early childhood periods. Age of the remaining patients ranged from 4 months to 47 years. This represents the largest collection of patients with STD reported and it has allowed us to determine a detailed phenotype. Given 56% survival at 6 months, we show that STD is not a lethal syndrome.

Abnormalities, Multiple↗

PubMed2004

Anti-inflammatory cytokines induce lipopolysaccharide tolerance in human monocytes without modifying toll-like receptor 4 membrane expression.

Toll-like receptor 4 (TLR4) participates in innate immunity by detecting lipopolysaccharides (LPS) of Gram-negative bacterial cell walls. TLR4 macrophage expression in mice is modulated by LPS. This fact constitutes, at least partially, the molecular basis for LPS tolerance. Very recently, the effect of interferon-gamma (IFN-gamma), a pro-inflammatory cytokine, has been described on TLR4 membrane expression of human monocytes. IFN-gamma up-regulates TLR4 expression and antagonizes the LPS-induced TLR4 down-regulation. These data prompted us to study the expression of membrane TLR4 in human mono- cytes in which LPS tolerance was induced by LPS and by anti-inflammatory cytokines [interleukin-10 (IL-10) and transforming growth factor beta1 (TGFbeta1)]. Data concerning this latter model, and more specifically, the effect of anti-inflammatory cytokines over TLR4 expression, are not available at present. We show here that membrane TLR4 expression in human monocytes falls after LPS exposure. The effect was prolonged for 12 h, but then expression returned to normal levels. The incubation of human monocytes with IL-10, TGFbeta1 or a mixture of both induces no alterations in membrane TLR4 expression. However, these cytokines are able to substitute the tolerizing LPS exposure in order to induce LPS tolerance. Our data help to achieve a better understanding of the way cytokines control the cellular expression of TLR.

Adult↗

PubMed2000

Diagnosing bile duct stones: comparison of unenhanced helical CT, oral contrast-enhanced CT cholangiography, and MR cholangiography.

OBJECTIVE: In this investigation we compared the diagnostic performance of unenhanced helical CT, oral contrast-enhanced CT cholangiography, and MR cholangiography for the diagnosis of choledocholithiasis. SUBJECTS AND METHODS: Fifty-one patients referred for endoscopic retrograde cholangiography of suspected biliary stones were studied with unenhanced helical CT, MR cholangiography, and helical CT performed after oral administration of a cholangiographic contrast agent (iopodic acid). The studies were randomized for interpretation. Two radiologists evaluated the images by consensus and determined the presence and location of stones. We used retrograde cholangiography findings as the standard of reference. Sensitivity and specificity (with 95% confidence intervals [CIs]) of the three examinations were calculated and compared using the exact form of the McNemar test. RESULTS: Bile duct stones were revealed with retrograde cholangiography in 26 patients (51%). Sensitivity was 65% (95% CI, 44.4-82%) for unenhanced helical CT, 92% (95% CI, 73-99%) for CT cholangiography, and 96% (95% CI, 78-99%) for MR cholangiography. Specificity was 84% (95% CI, 63-95%) for unenhanced helical CT, 92% (95% CI, 73-99%) for CT cholangiography, and 100% (95% CI, 83-100%) for MR cholangiography. The sensitivity of CT cholangiography and MR cholangiography was significantly higher than that of unenhanced helical CT (p<0.01). Differences in specificity were not significant. CONCLUSION: Our results indicate that oral contrast-enhanced CT cholangiography and MR cholangiography are significantly more sensitive than unenhanced helical CT for the detection of bile duct calculi.

Adolescent↗

PubMed2000

Polymorphisms of octopine dehydrogenase (Odh) in mollusks and implications for the neutralism-selectionism hypothesis.

Octopine dehydrogenase (Odh) was examined in several species of bivalves and gastropods and complemented with bibliographic data, to assess the controversy between neutralism and selectionism in explaining the maintenance of genetic variation in natural populations. This debate was the center of the molecular evolution and population genetic research in the 1970s and 1980s, but waned thereafter, without resolution. Although DNA data have been produced, implications are not understood. We examined the polymorphims of Odh in several species of bivalves and gastropods, and the kinetic properties (apparent Km) of the different isozymes in the scallop Euvola ziczac that indicates an apparent case of overdominance of the heterozygous individuals. The question "which of the two hypothesis is correct" has shifted with time to "how much influence did each factor have in the maintenance of genetic variation".

Amino Acid Oxidoreductases↗

PubMed1999

The development and validation of a Spanish version of the quality of life in depression scale (QLDS).

OBJECTIVE: The adaptation of the Quality of Life in Depression Scale, the QLDS, into Spanish. METHODS: The original UK version of the QLDS was considered by two translation panels, who produced a Spanish translation. Priority was given to conceptual rather than semantic equivalence. This version was then field-tested with 15 depressed patients. The final stage of the research involved a postal survey of 62 patients, who were asked to complete the measure on two occasions. RESULTS: The Spanish QLDS was found to be appropriate and acceptable by depressed patients. The questionnaire's test-retest reliability and internal consistency were both high, and QLDS scores correlated as predicted with scores on sections of the Nottingham Health Profile. The measure was sensitive to different levels of depression as assessed by the Hospital Anxiety and Depression Scale. CONCLUSION: The Spanish version of the QLDS is suitable for use in clinical trials and for monitoring individual patients in routine clinical practice.

Adaptation, Psychological↗

PubMed1994

Molecular cloning and nucleotide sequence of the coat protein gene of a Cuban isolate of potato leafroll virus and its expression in Escherichia coli.

Total RNA from infected Physalis floridana was isolated to generate complementary DNA corresponding to the coat protein (GP) gene of a Cuban isolate of potato leaf roll virus (PLRV). This cDNA was amplified by the polymerase chain reaction (PCR) and cloned into the bacterial expression vectors pEX(1-3) for fusion protein expression in E. coli. The product was detected by antibodies specific for the PLRV CP. The coding sequence of the CP gene was determined, and the predicted length of the CP was 208 amino acids (23 kD). The nucleotide sequences and deduced amino acid sequences were compared with the other PLRV isolates and found to be 97-99.5% identical at both the nucleotide and amino acid sequence level of other isolates. Comparison of the deduced amino acid sequences of the PLRVcub CP revealed considerable homology to other luteoviruses. We believe that the protocol described could be applicable to other plant viruses of low abundance or of cumbersome isolation, since this method is less time consuming than the traditional methods of cloning coat protein genes of plant viruses with known sequences.

Amino Acid Sequence↗

PubMed1992

Transfer of the tibialis anterior for calcaneus deformity in myelodysplasia.

We evaluated the results of transfer of the tibialis anterior in the management of calcaneus deformity in young patients who had myelodysplasia; fifteen patients (twenty-two feet) were operated on between 1978 and 1985. The neural deficit was at the fourth and fifth lumbar levels. The average age at the time of the operation was seven years and two months (range, two to nineteen years). The average age at the latest follow-up was thirteen years (range, five to twenty-four years). The average duration of follow-up was five years and ten months (range, two to eleven years). Seventeen feet (twelve patients) had a good result (no ulceration of the heel or osteomyelitis and correction of the calcaneus deformity), and five feet (three patients) had a poor result (persistent ulceration, signs of osteomyelitis, recurrent or persistent calcaneus deformity, or the need for additional operative intervention). Children who were less than five years old had a better outcome, as determined by the Fisher exact test (p less than 0.5).

Adolescent↗

PubMed1991

[Prevalence of bone dysplasias in newborns at the Ruíz y Páez Hospital in Bolívar City. Venezuela. 1978-1990].

A congenital malformations surveillance program in effect at the Ruiz y Páez Hospital in Ciudad Bolívar since April 1978, has allowed us to detect 25 patients with osteochondrodysplasias (OCD) in a total of 70,152 newborns, up to August 1990, for a prevalence of one case of OCD every 2,806 newborns. The clinical entities found were: Achondroplasia, Thanatophoric Dysplasia, Osteogenesis Imperfecta II-A, Camptomelic Dysplasia, Kniest Dysplasia, Conradi-Hunnerman syndrome, Parenti-Fracaro type Achondrogenesis and Jeune Asphyxiating Thoracic Dysplasia. The results presented in this paper indicate that this type of diseases represent a relatively important group of nosological entities adding up to more than 200 new annual cases in the country. This relatively high frequency, the different inheritance mechanisms involved, the variable complications and the high morbidity and mortality rate of these diseases, make the patients affected, a problematic group not receiving, in general, adequate medical attention regarding diagnosis, genetic counselling and treatment.

Bone Diseases, Developmental↗

PubMed1989

[Epidemiology of congenital malformations at the Ruiz and Páez Hospital of Bolívar City: a 10 years' experience].

From April 1978 to December 1988, we have studied the frequency of congenital malformations in newborns at the Ruiz y Páez University Hospital of Ciudad Bolivar. In that period 58,901 live births were observed, 1,821 of them presented at least one congenital malformation for a frequency of 30.9/1000. From January 1980 to December 1988, the number of stillbirths was 1097 with 44 of them congenitally malformed for a frequency of 40.1/1,000. Based on the data obtained, we consider that congenital malformations are a major public health problem that deserves national public programs to provide rational approaches to this situation. The frequency of each malformation and the characteristics of the control population are described. Some disadvantages of this type of investigation are considered, however, the need for other similar studies is emphasized in order to obtain a better understanding of the national status of the problem.

Congenital Abnormalities↗

PubMedDate not supplied

Back pain during orthotic treatment of idiopathic scoliosis.

The incidence and etiology of back pain during orthotic management of idiopathic scoliosis was determined for 303 patients treated from 1980 through 1990 for a minimum of 1 year. All patients denied back pain before orthotic prescription. Thirty-four (11%) patients reported back pain after institution of brace treatment. A family history of scoliosis (p = 0.014) and vigorous sports activities (p < 0.001) were correlated with pain. Seventeen of 34 patients with pain showed >10 degrees of curve progression during bracing, whereas 67 of 269 patients without pain progressed (p = 0.002). Four patients with pain and 11 without were eventually found to have an underlying pathology (spondylolysis/listhesis). No other underlying pathologies were found. Night pain or a left thoracic curve pattern were not correlated with a serious underlying etiology. Back pain occurring after institution of brace treatment for idiopathic scoliosis is often associated with curve progression and is poorly correlated with a serious underlying pathology.

Back Pain↗

PubMedDate not supplied

Confronting and eradicating an epidemic of bacteraemia.

Obtaining vascular access by catheterisation is a good option, especially in patients with vascular system fragility. In the authors' department, there was an increase in Gram Negative Bacillus (GNB) infection in patients with long term catheters (LTC). An objective was set to design an action plan and a new working methodology in order to eradicate the infection and the cause. Three periods were established in the prospective follow-up of LTC patients: the pre-epidemic period (01/94 to 03/99), with a bacteraemia every 144 days per patient, the epidemic period (04/99 to 12/00) with a bacteraemia every ten days per patient, and the post-epidemic period (01/01 to 04/02). A multidisciplinary working group was established, which produced action plans for nursing and technical staff. The working methodology of the service was studied and analysed by means of a review. The deionised water cultures at the entrance to the haemodialysis ward were negative. The dialysis and connector cultures were positive for GNB, confirming that they were of the same genetic origin. An evaluation of the periods was carried out, studying the working methodology, to which no changes were made between the pre-epidemic and epidemic period. In the post-epidemic period, a number of changes were made to the care dynamic, with no other bacteraemia arising to date. Adapting and improving protocols is a good indicator of quality. The role of nursing staff is vital in prevention of GNB.

Bacteremia↗

PubMedDate not supplied

Human and dogs Toxocara canis infection in a poor neighborhood in Bogota.

Prevalence of Toxocara canis antibodies was studied in a poor community of Bogotá, Colombia. Two-hundred-seven patients, from both sexes and all age groups, were studied. Positive ELISA titers were found in 47.5% of the population, a high prevalence compared with reports from developed countries. T. canis ova were positive in 43.6% of fecal samples from dog puppies. An endemic pattern of the disease is described: socioeconomic status, weather, pollution, poor hygiene and a significant population of infected dogs. Neither the physical examination nor ELISA titers could detect any case of T. canis disease.

Adolescent↗

PubMedDate not supplied

Nursing protocol for manipulation of haemodialysis catheters.

This study looked at the incidence of infection complications, in relation to central vein catheterisation as a provisional HD access, by means of the establishment of a nursing protocol for the handling of these catheters. Central vein catheterisation is a classical technique in Nephrology.

Adult↗

PubMedDate not supplied

[Electroconvulsive therapy and serotonergic system].

Evidence from several studies supports the involvement of several neurotransmitter systems in the mechanism of action and the clinical efficacy of the electroconvulsive therapy (ECT). However, more recent studies have reported serotonin, through the activation of several receptors, to be the neurotransmitter most frequently altered in ECT. With regard to the serotonergic system, several levels of alteration can be targeted, that concerning serotonin and its metabolite concentrations, that concerning changes in the density of presynaptic and postsynaptic receptors located both in brain tissue or in platelets, and finally, alterations at the intracellular signalling system or second messenger level.

Brain↗

PubMedDate not supplied

[Genetic dysfunction of the serotonin receptor 5-HT2A in psychiatric disorders].

So far, there is increasing evidence of the active role of molecular biology in the psychiatric nosology as well as in the identification of psychiatric fenotypes. In this respect, the neurotransmitter serotonin (5-HT) has been involved in the etiopathogeny of multiple psychiatry conditions, such as affective disorder, schizophrenia, panic disorder, obsessive-compulsive disorder, alcoholism, eating disorder and personality disorder. The 5-HT2 receptor family includes the subtype 5-HT2A, a G protein coupled receptor whose activation leads to the stimulation of the enzyme phospholipase C and to the subsequent hydrolysis of the membrane located phosphoinositides, with the synthesis of the second messengers inositol triphosphate and diacylglicerol. This paper includes a review of the main findings concerning the polymorphism of the 5-HT2A in psychiatric disorders.

Alcoholism↗

PubMedDate not supplied

[Instruments of depression assessment in schizophrenia].

Lately, numerous reports have focused on the evaluation of depressive symptoms of schizophrenia. This assessment has been hampered by the temporal variability of the depressive symptoms and by their overlap with both the negative symptoms of schizophrenia and the extrapyramidal effects of the antipsychotic treatment. So far, classical assessment instruments such as the Hamilton Depression Rating Scale (HDRS) or the Montgomery-Asberg Rating Depression Scale (MARDS) have been used in those patients suffering from schizophrenia with depressive symptomatology, despite the important limitations concerning their use in subpopulations other than the one they have been developed for. New specific depression scales for schizophrenia such as the Calgary Depression Scale for Schizophrenics (CDSS) seems to have more efficiency and ability to distinguish between depression, negative and extrapyramidal symptoms. The present paper reviews the instruments used so far on the assessment of depressive symptomatology in schizophrenic patients.

Basal Ganglia Diseases↗

PubMedDate not supplied

[An outbreak of gram-negative bacteremia (GNB), especially enterobacter cloacae, in patients with long-term tunnelled haemodialysis catheters].

Vascular access through a venous catheter for haemodialysis is associated with increased risk of thrombosis, central venous stenosis, short access survival and inadequate dialysis. The most important catheter-related complications, which determine method survival, are infection and dysfunction. In particular, infectious episodes are in some studies the leading cause for untimely catheter removal and for catheter-related morbidity but also for morbidity in dialysis patients. Double-lumen central venous catheters used for haemodialysis, are common causes of septicaemia. Most cases are caused by staphylococci. Episodes of gram-negative bacteriemia have been traced to bacterial contamination of water and/or dialysate, errors in dialyzer reprocessing, and improper setup procedures. In this paper, we describe and outbreak of gram-negative bacteremia, firstly E. cloacae, in an outpatients haemodialysis unit, in the patients with long-term tunnelled haemodialysis catheters. We describe the epidemic investigation that we achieved to identify the source of contaminating bacteria and the route by which bacteria gained access to the bloodstream. We prove the contamination by gram-negative bacterium of the water-distribution lines and haemodialysis machines. Moreover, E. cloacae strains isolated from the lines and machines are genotypically identical to the isolated from the patients. Also, we prove that the hands of health care personnel are unintentional carriers. The outbreak was finished when decontamination of dialysis machines was enhanced and dialyzer-priming fluid was modified.

Aged↗

PubMedDate not supplied

[Rhabdomyolysis due to polydipsia in a patient with psychotic disorder].

Polydipsia is a frequent clinical entity in psychiatric patients, especially in those with a psychotic disorder. Acute episodes of polydipsia can produce important metabolic alterations and even coma and death. Psychogenic polydipsia is a underestimated diagnosis, due to multiple causal factors and an etiology that has not been clearly established. We present the case of a patient with psychiatric background who was seen due to a clinical situation of severe acute renal failure by high rhabdomyolysis that needed hemodialysis, due to acute polydipsia. We also review some of the epidemiological and clinical factors and etiopathogeny of the polydipsia. It is considered necessary to keep in mind the in mind the diagnosis of polydipsia in any psychiatric patient showing acute symptoms of confusion.

Drinking Behavior↗