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Biomedical subjects

L Maldonado

Publications and source records attributed to L Maldonado.

At least 19 recordsLinked to original sources
PubMed2006

The effect of different propolis harvest methods on its lead contents determined by ET AAS and UV-visS.

Argentinean propolis is exported to different countries, specially Japan. The market demands propolis quality control according to international standards. The analytical determination of some metals, as lead in food, is very important for their high toxicity even in low concentrations and because of their harmful effects on health. Flavonoids, the main bioactive compounds of propolis, tend to chelate metals as lead, which becomes one of the main polluting agents of propolis. The lead found in propolis may come from the atmosphere or it may be incorporated in the harvest, extraction and processing methods. The aim of this work is to evaluate lead level on Argentinean propolis determined by electrothermal atomic absorption spectrometry (ET AAS) and UV-vis spectrophotometry (UV-visS) methods, as well as the effect of harvest methods on those contents. A randomized test with three different treatments of collection was made to evaluate the effect of harvest methods. These procedures were: separating wedges (traditional), netting plastic meshes and stamping out plastic meshes. By means of the analysis of variance technique for multiple comparisons (ANOVA) it was possible to conclude that there are significant differences between scraped and mesh methods (stamped out and mosquito netting meshes). The results obtained in the present test would allow us to conclude that mesh methods are more advisable than scraped ones in order to obtain innocuous and safe propolis with minor lead contents. A statistical comparison of lead determination by both, ET AAS and UV-visS methods, demonstrated that there is not a significant difference in the results achieved with the two analytical techniques employed.

Electrochemistry↗
PubMed2002

[Value of power Doppler ultrasonography with intravenous contrast medium (Levograf) in the diagnosis of acute cholecystitis].

The aim of this study was to evaluate the potential capacity of color and power Doppler sonography with intravenous contrast medium in the diagnosis of acute cholecystitis. We examined 18 patients with acute cholecystitis, 5 patients with chronic cholecystitis and a control group of 11 patients without gallbladder disease. In these patients, vascularization of the gallbladder wall was evaluated by color and power Doppler sonography before and after intravenous administration of contrast medium (Levograf). Vascularization was evaluated with a 3-point scale (grades 0, 1 and 3) according to the intensity and localization of signs of color. In the diagnosis of acute cholecystitis, basal examination with power Doppler had a sensitivity of 38.8%. After administration of intravenous contrast medium, sensitivity was 100%. In conclusion, the use of sonographic contrast media in the diagnosis of acute cholecystitis showed a sensitivity and specificity of 100%. This technique represents a viable diagnostic alternative to other complementary or imaging studies.

Acute Disease↗
PubMed2002

Improved detection of liver metastases with contrast-enhanced wideband harmonic imaging: comparison with CT findings.

OBJECTIVE: To evaluate the capability of contrast-enhanced wideband harmonic imaging (WHI) to detect liver metastases in comparison with fundamental B-mode US and postcontrast CT. METHODS: We studied 27 patients with hepatic metastases from different malignancies with conventional B-mode sonography, WHI 3 min after injection of contrast agent (Levovist(R) 2.5 g, 300 mg/ml) and postcontrast helical CT (HCT). The number and location of the lesions and the smallest lesion for each patient were noted by two different observers and compared. RESULTS: Both readers recorded an increase in the number of lesions in harmonic mode compared with conventional B-mode in all 27 patients with hepatic metastases with a mean increase in both observers from 9.3 lesions with B-mode to 18.8 lesions with WHI. The smallest lesions were detected with WHI when compared with conventional US and HCT (2 mm with WHI, 5 mm with B-mode and 5 mm with CT). WHI detected more lesions than conventional US or HCT. CONCLUSIONS: Contrast-enhanced WHI seems superior to conventional US and HCT for the detection of hepatic metastases, specially for those nodules under 1 cm of diameter.

Adult↗
PubMed2001

Activity of Crohn's disease assessed by colour Doppler ultrasound analysis of the affected loops.

The aim of this study was to evaluate with colour Doppler ultrasound the vascular changes in the wall of the loops affected by Crohn's disease, and to establish whether these changes reflects clinical or biochemical activity of Crohn's disease. Seventy-nine patients with Crohn's disease (44 with active disease and 35 inactive patients) were studied with frequency- and amplitude-encoded duplex Doppler sonography. A group of 35 healthy volunteers were also included. The exam consisted of the search for colour signals in the walls of the loops affected by Crohn's disease, classifying the degree of vascularity with a simple scoring system into three groups: absence of colour signal (score of 0); weak or scattered colour signals (score of 1); and multiple colour signals or clear identification of vessels in the loops walls (score of 2). Doppler curves were obtained of the detected vessels with measurement of the resistive index (RI). There was a visible increase in the gut walls' vascularity in the active patients compared with those with inactive disease. The mean RI was statistically significantly lower in the gut wall vessels of the patients with active illness than that obtained in the inactive patients. Colour Doppler ultrasound is a useful tool in the assessment of activity in Crohn's disease.

Adolescent↗
PubMed2001

Nocardia beijingensis sp. nov., a novel isolate from soil.

The taxonomic status of a soil isolate, provisionally assigned to the genus Nocardia, was established following a polyphasic study. An almost complete sequence of the 16S rDNA of the strain was determined and aligned with available sequences for nocardiae and phylogenetic trees were inferred using four tree-making algorithms. The organism was associated consistently with the type strains of Nocardia brasiliensis and Nocardia farcinica in the neighbour-joining analysis, albeit with low bootstrap values. It was also found to have chemotaxonomic and morphological properties consistent with its assignment to the genus Nocardia. The organism was readily separated from representatives of other Nocardia species by a broad range of phenotypic properties. The name proposed for the novel species is Nocardia beijingensis sp. nov. The type strain is AS4.1521T (= IFO 16342T = JCM 10666T).

Base Composition↗
PubMed2001

Nocardia africana sp. nov., a new pathogen isolated from patients with pulmonary infections.

Eight actinomycete strains, isolated from 8 out of 400 sputum samples examined, taken from patients with pulmonary diseases at the Chest Unit of Khartoum Teaching Hospital in the Sudan, were provisionally assigned to the genus Nocardia according to morphological criteria. These isolates were studied further in order to establish their taxonomic status. They were found to have morphological and chemical properties typical of nocardiae and formed a monophyletic clade in the 16S ribosomal DNA tree together with Nocardia vaccinii. The strains showed a unique pattern of phenotypic properties that distinguished them from representatives of recognized Nocardia species, including Nocardia vaccinii. The strains were considered to merit species status and were designated Nocardia africana sp. nov. The findings of the present study are consistent with the view that pulmonary nocardiosis may occur in a substantial proportion of patients who exhibit chronic lung diseases in African countries. It is important, therefore, that clinicians in such countries consider this condition, especially when patients with respiratory infections fail to respond to antitubercular therapy.

Africa↗
PubMed2000

The Nocardia salmonicida clade, including descriptions of Nocardia cummidelens sp. nov., Nocardia fluminea sp. nov. and Nocardia soli sp. nov.

Large numbers of strains selectively isolated from soil, water and deteriorating vulcanised natural rubber pipe rings were provisionally assigned to the genus Nocardia. Twenty-eight representative isolates were found to have chemical and morphological properties typical of nocardiae. These organisms formed a monophyletic clade in the 16S rDNA tree together with Nocardia salmonicida. Three of the strains, isolates S1, W30 and R89, were distinguished from one another and from representatives of the validly described species of Nocardia using genotypic and phenotypic data. These organisms were considered to merit species status and were named Nocardia cummidelens sp. nov., Nocardia fluminea sp. nov. and Nocardia soli sp. nov. respectively. Additional comparative studies are needed to resolve the finer taxonomic relationships of the remaining isolates assigned to the Nocardia salmonicida clade and to further unravel the extent of nocardial diversity in artificial and natural ecosystems.

DNA, Bacterial↗
PubMed1997

Prevalence and incidence of gallstones in liver cirrhosis.

BACKGROUND: Our aim was to assess the prevalence and incidence of gallstone disease in patients with liver cirrhosis and to identify risk factors for cholecystolithiasis. METHODS: We studied a cohort of 313 patients with liver cirrhosis confirmed by histology and/or laparoscopy and 357 patients free of liver disease, who had been referred for ultrasonographic examination of the upper abdomen. Hepatobiliary ultrasonography was performed when liver cirrhosis was diagnosed and every 6 months thereafter. Risk factors for cholelithiasis (age, gender, diet, pregnancy, diabetes, family history of cholelithiasis, etiology of cirrhosis, decompensated disease) were assessed. RESULTS: The overall prevalence of gallstones in cirrhotic patients was 23.3%. In controls, the overall prevalence of cholecystolithiasis was 16.8%. After a median follow-up period of 65 months, 30 patients developed gallstones. The calculated annual incidence was 3.4%. CONCLUSIONS: Given that the prevalence of gallstone disease is higher in cirrhotics than in noncirrhotic patients, cirrhosis of the liver may be considered a risk factor for cholecystolithiasis.

Cholelithiasis↗
PubMed1997

Peripherally inserted central catheters in general medicine.

OBJECTIVE: To report the success rate and complications associated with peripherally inserted central venous catheters (PICCs) and to compare costs between PICCs and centrally inserted central catheters. MATERIAL AND METHODS: We undertook a cohort study of the first 1,000 patients referred to the PICC service of a large tertiary-care, university-affiliated, community hospital. The data were analyzed for insertion success rate, insertion mode, complication rate, successful completion, insertion costs, and applicability of PICCs in "high-risk" groups (transplant, human immunodeficiency virus-infected, intensive-care unit, and pediatric populations). RESULTS: Of 1,000 consecutive PICC attempts, 963 (96.3%) were successful. Cutdown procedures were necessary in 141 insertions (14.6%). Complications of PICC placement occurred in 170 cases (17.7%). Among the major complications were a need for multiple attempts at insertion in 92 cases, malpositioning in 56, mechanical phlebitis in 37, clotting in 37, and bleeding in 5. The rate for completion of therapy was 68.9%. Frequent reasons for early termination were dislodgment (in 85 cases) and infection (in 72-37 confirmed and 35 potential cases). The rate of confirmed infection was 11 per 10,000 catheter days. The costs of PICC insertion were less than those associated with centrally inserted central catheters. CONCLUSIONS: PICCs can satisfy long-term vascular needs and are safe in many patient populations. The infection rate did not depend on insertion mode, lumen number, or patient's immune status. Use of total parenteral nutrition was the most important risk factor in all patient subsets. Cost and safety considerations strongly favor PICCs as alternatives to other vascular access devices.

Catheterization, Central Venous↗
PubMed1996

Upper gastrointestinal hemorrhage clinical--guideline determining the optimal hospital length of stay.

PURPOSE: Physicians lack objective outcome data to define the medically appropriate length of stay (LOS) for patients hospitalized with acute upper gastrointestinal hemorrhage (UGIH), resulting in wide variations in resource utilization and quality of care. A clinical practice guideline with the ability to assign relative risk for adverse events is proposed. METHODS: A comprehensive scoring system was derived from the literature by using four variables; hemodynamics, time from bleeding, comorbidity, and esophagoduodenoscopy findings. The discriminatory ability, potential safety, and impact on resource utilization of the clinical practice guideline was measured in a retrospective, observational study. RESULTS: Seventy percent of UGIH patients (349 of 500) achieved low-risk status according to the guideline, and, were therefore potentially suitable for early discharge from the hospital. If low-risk patients were discharged based upon the guideline, mean (+/- SD) hospital LOS would have been decreased from 4.8 +/- 2.4 days to 2.7 +/- 1.4 days; mean reduction was 2.1 bed-days per patient (95% CI 1.8 to 2.3, P <0.001). LOS would have increased in 4% of cases. Adopting the guideline's recommendation of early discharge would have resulted in a 0.6% (95% CI 0.07 to 2.1) complication rate, with no worsening of quality of care, as judged by implicit review. CONCLUSIONS: The proposed clinical practice guideline may safely reduce hospital LOS for selected low-risk patients with acute UGIH. Moreover, it also may reduce premature discharge of high-risk patients prone to life-threatening events.

Acute Disease↗
PubMed1991

Obstructive uropathy following aortofemoral graft surgery.

Fifty patients who had undergone aorto-bifemoral bypass with a bifurcated Dacron graft for aortoiliac arteriosclerotic obliteration were examined with real-time sectorial ultrasound to screen for the presence of hydronephrosis. Hydronephrosis was detected in only 1 case. The low incidence of this complication in our cases may be due to the fact that all our patients were explored at least 1 year after surgery. Some may have developed hydronephrosis early, but this may have resolved spontaneously during the first year after the operation, thus remaining undiagnosed. Pathogenic mechanisms suggested for the development of hydronephrosis and therapeutic approaches are discussed. We conclude that pre- and postoperative ultrasound examination and follow-up beyond 1 year postoperatively seem to be fully justified in all patients who undergo aortoiliac or aortofemoral reconstructive surgery.

Aorta, Abdominal↗
PubMed1990

Transitional cell carcinomatous meningitis after M-VAC (methotrexate, vinblastine, doxorubicin, and cisplatin) chemotherapy.

The M-VAC (methotrexate, vinblastine, doxorubicin, and cisplatin) regimen has been utilized at our two institutions to treat 17 patients with advanced stage transitional cell carcinoma of the bladder. We report 2 cases of carcinomatous meningitis resulting from metastatic transitional cell carcinoma which occurred in patients treated with M-VAC. Review of the literature suggests that our experience with central nervous system metastases is not unique, and that treatment of advanced stage transitional cell carcinoma of the bladder with M-VAC may enhance the incidence of meningeal metastases. Carcinomatous meningitis, although rare, is a rapidly fatal manifestation of metastatic transitional cell carcinoma if left untreated. However, prompt diagnosis and early aggressive therapy may result in palliation and stabilization of neurologic status. We review the pathophysiology, diagnosis, and treatment of transitional cell carcinomatous meningitis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1990

The principle of parsimony: Glasgow Coma Scale score predicts mortality as well as the APACHE II score for stroke patients.

Although the development and use of severity-of-illness measures has gained widespread enthusiasm, uncertainty remains as to the optimal measure for stroke patients. The Health Care Financing Administration recently derived a severity-of-illness measure based on the APACHE II system to explain differences in Medicare mortality rates among hospitals treating stroke patients. We hypothesized that the Glasgow Coma Scale score provides prognostic information of accuracy comparable to that of the APACHE II score for stroke patients, yet is simpler and cheaper to abstract from the medical record. We therefore studied 246 patients hospitalized with stroke, including 49 oversampled mortalities. The Glasgow Coma Scale score was as accurate as the APACHE II score in predicting stroke mortality both before (r = -0.50 and r = 0.50, respectively) and after (r = -0.40 and r = 0.38, respectively) the oversampled mortalities were excluded. The APACHE II score required abstraction of 16 variables from the medical record compared with three for the Glasgow Coma Scale score and required more than three times the time to abstract from the medical record. Therefore, in the interest of parsimonious data collection, the Glasgow Coma Scale may be a preferable severity-of-illness measure for patients with stroke.

Aged↗