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D Jimenez

Publications and source records attributed to D Jimenez.

13 recordsLinked to original sources
PubMed2000

A multirate scan conversion method

B-mode ultrasonic imaging requires that the acquired polar coordinate ultrasound data be converted to the Cartesian format used by digital monitors. Image quality depends on the interpolation algorithm used to this purpose. In this work a selective sampling technique, based on acquiring data at specific points of the scanned area together with a straightforward linear interpolation step, is proposed. Hardware complexity is avoided, because the interpolation task can be carried out by software in real time, concurrently with data acquisition. The performances of the proposed approach are analysed with regard to those provided by other algorithms and some implementation issues are addressed.

Journal Article↗
PubMed1997

Use of carbidopa-levodopa in a patient with hydrocephalus and frozen movement.

While movement disorders are frequently encountered after brain injuries, and may create a host of complicated problems for the clinician, only a few cases of Parkinsonism associated with hydrocephalus have ever been described in the literature. Parkinsonism-like syndrome complicating hydrocephalus is a rare disorder, especially when associated with nontumoral aqueductal stenosis. Yet as this case report discusses, hdyrocephalus-induced Parkinsonism may be responsive to levodopa-carbidopa administration. This report describes a perplexing case of persistent akinesis following corrective surgery for aqueductal stenosis and the subsequent response to levodopa-carbidopa administration. We present the case of a 28-year-old male with a history of non-tumoral aqueductal stenosis diagnosed at age 12. As a child, he underwent a ventriculo-peritoneal shunt placement for obstructive hydrocephalus followed by multiple shunt revisions over the next several years. Sixteen years after his initial shunt placement, the patient presented with a decline in mental status. A third ventriculocisternostomy was performed rather than another shunt revision. Following surgery, the patient remained obtunded, and displayed profound hypokinesis, best described as freezing in movement. Upon admission to a rehabilitation unit 2 weeks later, he had made only minimal progress. A SPECT (single-photon emission computed tomography) brain scan revealed decreased basal ganglia perfusion. Levodopa/carbidopa therapy was initiated and within 2 weeks, the patient showed improvement in speed of movement, facial expression and verbal output. Eight weeks later, the patient could independently complete his basic activities of daily living and demonstrated little, if any, disordered movement. This report illustrates how dopaminergic agents may be useful in cases of hypokinesis following corrective surgery for aqueductal stenosis. SPECT may further aid in the diagnosis and management of Parkinsonism-like syndromes in brain injuries.

Adult↗
PubMed1994

Cardiovascular and cerebrovascular effects of the applied Valsalva manoeuvre in anaesthetized neurosurgical patients.

We examined the effects of Valsalva's manoeuvre and its four phase on heart rate, central venous pressure (CVP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP), and laser Doppler cerebellar cortical blood flow (CBF). Brief Valsalva manoeuvres increased CVP and markedly decreased MAP. Cerebral perfusion pressure significantly (P < or = 0.01, Dunnett's test) decreased during phases 2 and 3 of the Valsalva manoeuvre. Cortical blood flow closely paralleled CPP; CBF decreased to 59% of control during phase 2 and to 57% of control during phase 3 of the Valsalva manoeuvre. The MAP, CPP, and CBF all returned to baseline levels during phase 4 (the overshoot phase) of the Valsalva manoeuvre, and were not significantly greater than control. No autoregulatory change in cerebrovascular resistance occurred throughout the Valsalva manoeuvre. These results suggest that brief Valsalva manoeuvres, as employed during neurosurgical procedures, mainly confirm venous haemostasis, but must be used cautiously due to the marked haemodynamic changes.

Aged↗
PubMed1993

Ten-year survey of quinolone resistance in Escherichia coli causing urinary tract infections.

In a ten-year survey (1983-1992) of quinolone resistance in Escherichia coli causing urinary tract infections in a general practice patient population, 9,934 strains were tested. Resistance increased remarkably from 1989 onwards. The rate of resistance to pipemidic acid was < or = 6% before 1989 and 18% in 1992; the rate of resistance to ciprofloxacin (MIC > or = 4 mg/l) was 0.8% in 1989 and 7.1% in 1992. Although the consumption of older quinolones decreased the total consumption of quinolones increased yearly.

Anti-Infective Agents↗
PubMed1992

Maternal leukocyte metabolism during pregnancy and puerperium, and its relation to fetal growth.

Changes of energy metabolism in maternal leukocytes were studied longitudinally in 33 normal term pregnancies at 12, 20 and 36 weeks of gestation and 40 days post partum. Nutrient intakes were calculated from 3-day weighed food records at the same periods. Women tended to decrease their mean dietary intakes of energy and of most nutrients from early to late pregnancy. Glucose-6-P dehydrogenase (G6P-DH), pyruvic kinase (PK) and adenylate kinase (AK) activities rose significantly after the 12th week of pregnancy, reaching maximal values at week 20. The following period up to week 36 showed a significant decrease that continued in the puerperium, when their values were lowest. Adenine nucleotide contents and protein/DNA ratio followed a different pattern. A significant increase was also observed from weeks 12 to 20, remaining without changes during the second half of gestation, and falling at puerperium. The PK and AK activities showed a positive correlation with energy intake at 36 weeks of gestation and AK activity was negatively correlated with folic acid intake in the middle of pregnancy. At week 20, PK activity showed a positive correlation with both head circumference and body mass index of the newborn. There was also a correlation between protein/DNA ratio and head circumference at the 36th week of gestation. These findings may suggest a relationship between the metabolism of maternal leukocytes, and fetal development in utero.

Adenine Nucleotides↗
PubMed1991

The NHLBI Twin Study: heritability of apolipoprotein A-I, B, and low density lipoprotein subclasses and concordance for lipoprotein(a).

Heritability of plasma apolipoprotein (apo) A-I, apo B, and low density lipoprotein (LDL) subclasses and concordance for lipoprotein(a) excess were assessed in 109 monozygotic (MZ) and 113 dizygotic (DZ) twin pairs participating in the third examination of the National Heart, Lung, and Blood Institute Twin Study. The intraclass correlation coefficient for apo A-I was significantly greater in MZ twins (0.56) than in DZ twins (0.37, P less than 0.05); however, apo A-I showed an unequal distribution in the two groups, with significantly greater total variance in DZ twins. Therefore the among-component estimate of genetic variance was applied, and the results indicated no significant heritability for apo A-I (P = 0.59). MZ and DZ twins had equal apo B variance. The intraclass correlation coefficient for apo B in MZ twins (0.71) was significantly higher than in DZ twins (0.25) (P less than 0.0001), indicating significant heritability for apo B. Plasma apo A-I levels were significantly correlated with alcohol intake (P less than 0.0001), body mass index (BMI, P less than 0.0001), and physical activity, while apo B levels were significantly correlated only with BMI (P less than 0.05). After plasma apo A-I and apo B concentrations were adjusted for all of these variables and for cigarette smoking, the analysis of variance and intraclass correlation coefficients remained virtually unchanged. The LDL type intraclass correlation coefficient was higher in MZ twins (0.58) than in DZ twins (0.32, P less than 0.005); however, greater total variance for this parameter in DZ twins was observed and after applying the among component estimate of genetic variance, no significant heritability of LDL type was observed. After adjustment for covariate effects the conclusions were not changed. Only 8.4% of MZ twin pairs, as compared with 26.7% of DZ twin pairs, were discordant for elevated lipoprotein(a) on gradient gels (P less than 0.0001). Our data indicate that there is a strong heritability for plasma apo B and lipoprotein(a), with only weak evidence for heritability of LDL type or plasma apo A-I levels within this population sample.

Aged↗
PubMed1988

Plasma lipids and high density lipoprotein cholesterol in maternal and umbilical vessels in twin pregnancies.

Total cholesterol (TC), triglycerides (TG), phospholipids (PL), Unesterified cholesterol (UC) and high-density lipoprotein cholesterol (HDL) were measured in 30 plasmas from twin pregnant women and their newborns, and 60 maternal single infant pairs. Blood samples were obtained simultaneously from maternal vein, umbilical artery and umbilical vein at the moment of partum. TG from twin pregnant mothers was much higher and HDL-C lower than that from single pregnant maternal plasma TC, TG and PL in umbilical cord vessels showed no differences between twin and single newborns. There was a weak, but statistically significant, positive correlation between maternal and fetal levels of PL in both groups. A high difference between TC, TG and PL in umbilical venous and umbilical arterial plasma was found These data suggest that some fetal lipid moieties derived from maternal plasma. But data about fetal body composition indicate that contribution of maternal lipids to the fetus is of small quantitative importance.

Adult↗
PubMed1983

Murine mammary tumor virus related antigen in human male mammary carcinoma.

An antigen immunologically related to mouse mammary tumor virus (MuMTV) and the major envelope glycoprotein, gp52 of MuMTV, was identified in tissue sections of human male and female mammary carcinomas using the peroxidase-antiperoxidase technique. The specificity of the reaction was established by absorption studies. Positive reactions with the gp52 antiserum were seen in mouse and human mammary carcinomas, but not in normal mammary tissues, mammary tissues with benign diseases and in other primary malignant neoplasms. Almost all (32/36, 89%) male mammary carcinomas were positive for the gp52 related antigen. A lesser proportion of tumors among female patients (14/50, 28%) were positive. The gp52 positive tumors were significantly larger than the gp52 negative tumors in female patients (P less than 0.05). Gp52 positive tumors were also larger than gp52 negative tumors in male patients, but the difference was not statistically significant. Gp52 reactivity was also detected in metastatic mammary carcinoma in axillary lymph nodes of male and female patients. The presence of gp52 related antigen was not apparently related to tumor grade or lymphocytic infiltrate in the primary tumor. The data do not permit a firm conclusion regarding nodal status in men; no correlation of gp52 activity and nodal status in women was evident. These results indicate that mammary carcinomas in men as well as in women have an antigen related immunologically to MuMTV gp52. Other than tumor size, the antigen seems to be unrelated to major prognostic factors. The significance of the antigen with respect to etiologic features and prognosis in breast cancer remains to be determined.

Adenocarcinoma↗
PubMed1981

Multifocal varicella-zoster virus leukoencephalitis temporally remote from herpes zoster.

Two patients with cancer, one with Hodgkin's disease and the other with a granulosa cell tumor of the ovary, developed a progressive, eventually fatal infection of the central nervous system exhibiting multifocal symptoms and signs. Pathologically, gross abnormalities of the brain resembled those in progressive multifocal leukoencephalopathy (PML), with discrete and confluent plaque-like lesions concentrated in the white matter, particularly along the gray-white junction. Microscopically, pathological changes differed distinctly from those associated with PML; in addition to confluent foci of white matter injury characterized by early demyelination and subsequent necrosis, prominent Cowdry type A eosinophilic intranuclear inclusions were noted in oligodendrocytes, astrocytes, and neurons. By electron microscopy, intranuclear spherical particles consistent in size and appearance with herpesvirus nucleocapsids were found within the lesions. Immunoperoxidase studies detected varicella-zoster virus (VZV) antigens in infected cells, implicating this virus as the responsible agent despite a lapse of many months between the cutaneous herpes zoster and onset of cerebral symptoms in both patients.

Adult↗