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Biomedical subjects

M Martinez

Publications and source records attributed to M Martinez.

At least 109 records · Page 6Linked to original sources
PubMed1999

Free and conjugated polyamines and phenols in raw and alkaline-clarified sugarcane juices.

Sugarcane juice contains a lot of sucrose associated with several monosaccharides, defined as low molecular mass carbohydrates (LMMC), as well as some polysaccharides and glycoproteins, which are defined as mid and high molecular mass carbohydrates (MMMC and HMMC, respectively). These three categories of carbohydrates can be separated by size-exclusion chromatography through Sephadex G-10 and Sephadex G-50 columns, but elution profiles change drastically after juice clarification performed by adjusting the pH value of the juice to 8.0. In addition, polyamines and some phenolics are currently associated with carbohydrate preparations, and the distribution pattern of these conjugates also changes after clarification. Polyamine levels generally decrease after juice clarification. Cadaverine is completely removed from the different carbohydrate preparations, whereas spermidine is the main polyamine occurring in association with sugarcane carbohydrates, as free or acid-soluble form in LMMC preparation or as acid-soluble and -insoluble forms in both MMMC and HMMC preparations. Polyamines, presumably spermidine, conjugate to p-hydroxybenzoic acid in LMMC, mostly to caffeic acid in MMMC, and to syringic acid in HMMC preparations. HMMC-associated polyamines appear in both acid-soluble and -insoluble fractions. Syringic acid also occurs in the LMMC preparation, but juice clarification changes it from acid-soluble to free form, and it coelutes with sucrose.

Food Handling↗
PubMed1999

Adrenomedullin, a vasodilator peptide implicated in hemodynamic alterations of liver cirrhosis: relationship to nitric oxide.

This prospective cohort study was aimed at investigating the role of adrenomedullin, a potent vasodilator peptide, in liver cirrhosis and its relationship with nitric oxide and cytokines. Overall, 66 consecutive patients with liver cirrhosis and 15 controls matched for age and sex distribution were included. Adrenomedullin levels in patients with cirrhosis were higher than in controls [28.1 (23.5-34.8) vs 21.9 (21.1-26.4) pmol/liter, P = 0.002]. Child class A patients had adrenomedullin levels similar to those of controls, but lower than patients in class B and C, respectively (P = 0.01). Patients with ascites showed more elevated adrenomedullin levels than patients without (P = 0.001). Adrenomedullin levels had significant correlations with aldosterone (r = 0.55; P < 0.001), plasma renin activity (r = 0.49; P < 0.001) and nitrates-nitrites levels (r = 0.52; P < 0.001). Weak correlations were found with tumor necrosis factor-alpha and interleukin-6. This study shows that high levels of adrenomedullin in liver cirrhosis correlate with features associated with plasma volume expansion, and suggests that, in late stages of cirrhosis, adrenomedullin might contribute to vasodilatation by increasing the generation of nitric oxide.

Adrenomedullin↗
PubMed1999

Cavernous angioma of the conus medullaris as a cause of paraplegia.

Cavernous angiomas of the conus medullaris are unusual lesions, representing about 3% of all intramedullary cavernomas. Most are asymptomatic. Magnetic resonance imaging (MRI) is the best diagnostic tool for the detection. We report a case of a 74-year-old man who initially developed low back pain and numbness of the right leg and subsequently paraplegia, ASIA impairment scale 'c'. MRI revealed a cavernous angioma of the conus medullaris with perilesional oedema and signs of acute bleeding. Clinical improvement was associated with changes in the MRI.

Aged↗
PubMed1999

A third major locus for autosomal dominant hypercholesterolemia maps to 1p34.1-p32.

Autosomal dominant hypercholesterolemia (ADH), one of the most frequent hereditary disorders, is characterized by an isolated elevation of LDL particles that leads to premature mortality from cardiovascular complications. It is generally assumed that mutations in the LDLR and APOB genes account for ADH. We identified one large French pedigree (HC2) and 12 additional white families with ADH in which we excluded linkage to the LDLR and APOB, implicating a new locus we named "FH3." A LOD score of 3.13 at a recombination fraction of 0 was obtained at markers D1S2892 and D1S2722. We localized the FH3 locus to a 9-cM interval at 1p34.1-p32. We tested four regional markers in another set of 12 ADH families. Positive LOD scores were obtained in three pedigrees, whereas linkage was excluded in the others. Heterogeneity tests indicated linkage to FH3 in approximately 27% of these non-LDLR/non-APOB ADH families and implied a fourth locus. Radiation hybrid mapping located four candidate genes at 1p34.1-p32, outside the critical region, showing no identity with FH3. Our results show that ADH is genetically more heterogeneous than conventionally accepted.

Adult↗
PubMed1999

Early-onset autosomal dominant Alzheimer disease: prevalence, genetic heterogeneity, and mutation spectrum.

To determine the prevalence of early-onset Alzheimer disease (EOAD) and of autosomal dominant forms of EOAD (ADEOAD), we performed a population-based study in the city of Rouen (426,710 residents). EOAD was defined as onset of disease at age <61 years, and ADEOAD was defined as the occurrence of at least three EOAD cases in three generations. Using these stringent criteria, we calculated that the EOAD and ADEOAD prevalences per 100,000 persons at risk were 41.2 and 5.3, respectively. We then performed a mutational analysis of the genes for amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2) in 34 families with ADEOAD ascertained in France. In 19 (56%) of these families, we identified 16 distinct PSEN1 missense mutations, including 4 (Thr147Ile, Trp165Cys, Leu173Trp, and Ser390Ile) not reported elsewhere. APP mutations, including a novel mutation located at codon 715, were identified in 5 (15%) of the families. In the 10 remaining ADEOAD families and in 9 additional autosomal dominant Alzheimer disease families that did not fulfill the strict criteria for ADEOAD, no PSEN1, PSEN2, or APP mutation was identified. These results show that (1) PSEN1 and APP mutations account for 71% of ADEOAD families and (2) nonpenetrance at age <61 years is probably infrequent for PSEN1 or APP mutations.

Adult↗
PubMed1999

Genome-wide scan for autism susceptibility genes. Paris Autism Research International Sibpair Study.

Family and twin studies have suggested a genetic component in autism. We performed a genome-wide screen with 264 microsatellites markers in 51 multiplex families, using non-parametric linkage methods. Families were recruited by a collaborative group including clinicians from Sweden, France, Norway, the USA, Italy, Austria and Belgium. Using two-point and multipoint affected sib-pair analyses, 11 regions gave nominal P -values of 0.05 or lower. Four of these regions overlapped with regions on chromosomes 2q, 7q, 16p and 19p identified by the first genome-wide scan of autism performed by the International Molecular Genetic Study of Autism Consortium. Another of our potential susceptibility regions overlapped with the 15q11-q13 region identified in previous candidate gene studies. Our study revealed six additional regions on chromosomes 4q, 5p, 6q, 10q, 18q and Xp. We found that the most significant multipoint linkage was close to marker D6S283 (maximum lod score = 2.23, P = 0.0013).

Adolescent↗
PubMed1999

Interdisciplinary ambulatory education and service in primary care at the University of New Mexico.

To compete and survive in a managed care market, academic health centers must develop integrated delivery systems in general and an integrated primary care system in particular. However, the departmental-based structure at most academic health centers is ill-suited to this purpose. Service and education are usually segregated by department, and the professional activities of primary care faculty in different departments are fragmented, leaving them weakened as a political force within the institution. The University of New Mexico established a model of integrated primary care education and service by creating three interdisciplinary primary care clinics staffed by primary care residents and faculty. The clinics attracted a substantial portion of each department's faculty and residents. The clinics united primary care providers from different departments as a stronger, more unified voice in negotiating with the hospital and in fostering needed changes for primary care in the institution. Interdisciplinary teams require considerable time and labor both in planning (because of joint decision making) and in operation. Better staff structures and staff development must be learned through trial and error because there are not established benchmarks for interdisciplinary teams. Governance presents problems, primarily because loyalties to departments may supersede those to the clinic practice, and sometimes the departments' teaching priorities are challenged by clinic directors' need to ensure filling their interdisciplinary staff needs. These obstacles to collaboration can be addressed creatively, and ultimately the comprehensiveness and quality of care convinces providers and the institution.

Academic Medical Centers↗
PubMed1999

MRI dosimetry: a fast quantitative MRI method to determine 3D absorbed dose distributions.

RATIONALE AND OBJECTIVES: Magnetic resonance imaging (MRI) techniques seem to be very promising for 3D dosimetry studies, but long imaging acquisition time limits their use. A new fast T1 mapping protocol, easy to implement on a conventional MR imager, has been used to determine dose distributions on Fricke gels. METHODS: The method has been tested on manganese chloride (MnCl2) doped ferrous gelatin gels. The T1 measuring times range from 1 minute 40 seconds to 3 minutes 30 seconds for a 256x256 matrix image. RESULTS: The two- and three-dimensional profiles agree with those obtained with conventional dosimetry techniques (ion chambers). The precision and the spatial resolution principally depend on the signal-to-noise ratio of the used imaging RF coil. For example, for a surface coil, the accuracy is about 2.5% with a 1.56 mm spatial resolution. CONCLUSION: These preliminary results support the feasibility of the proposed technique for accurate MRI dosimetry studies and also have potential for various clinical quantitative MRI applications.

Gels↗
PubMed1999

Interleukin-6, nitric oxide, and the clinical and hemodynamic alterations of patients with liver cirrhosis.

OBJECTIVE: Nitric oxide has been proposed as a mediator of hyperdynamic circulation in cirrhosis. Endotoxin and cytokines induce the synthesis of nitric oxide. The aim of this study was to investigate the relationship between endotoxemia, cytokines, and nitric oxide in patients with cirrhosis, and to correlate these findings with clinical, biochemical, and hemodynamic parameters. METHODS: Clinical, biochemical, and hemodynamic parameters were assessed in 66 patients with cirrhosis and 15 controls. Levels of antidiuretic hormone, plasma renin activity, aldosterone, interferon gamma, interleukin-1, interleukin-6, tumor necrosis factor alpha, endotoxin, and nitrates-nitrites were determined. RESULTS: Mean arterial pressure was lower and interleukin-6, tumor necrosis factor alpha, nitrites-nitrates levels, and endotoxin positivity rates were higher in cirrhotics than in controls (p < 0.005). Mean arterial pressure decreased and interleukin-6 levels increased with worsening of Child score (p < 0.005). Patients with ascites had higher levels of interleukin-6, tumor necrosis factor alpha, and nitrates-nitrites than patients without ascites (p < 0.01). Elevated levels of interleukin-6 were found in patients with encephalopathy grade I, compared with patients without (p < 0.001); this association was independent of the severity of liver disease. In patients with low mean arterial pressure, interleukin-6 levels were higher than in patients with high mean arterial pressure (p = 0.001), whereas tumor necrosis factor alpha and nitrates-nitrites levels were not different. By multivariate analysis, high interleukin-6 levels showed independent associations with the presence of ascites, encephalopathy, and low mean arterial pressure. Only interleukin-6 levels had significant correlations with Child score, plasma renin activity, serum and urinary sodium, and mean arterial pressure (r > or = 0.4, p < 0.005). CONCLUSIONS: Although the activity of the nitric oxide pathway is increased in patients with cirrhosis and might contribute to the hemodynamic alteration, other factors are involved. Interleukin-6, possibly through nitric oxide-independent mechanisms, also might play a role in the vasodilatation of cirrhosis and the pathogenesis of hepatic encephalopathy.

Aged↗
PubMed1999

Vertebral Aspergillus osteomyelitis and acute diskitis in patients with chronic obstructive pulmonary disease.

Aspergillus osteomyelitis of the spine with acute diskitis has been well documented in immunocompromised hosts but is rare in immunocompetent patients. Predisposing factors to infection are prolonged neutropenia, hematologic malignancies, chemotherapy, history of prior spinal trauma or surgery, allograft transplantation, or any condition requiring the use of long-term immunosuppressive agents or systemic corticosteroids. Patients with chronic obstructive pulmonary disease (COPD) treated with systemic corticosteroids for either long-term management or frequent exacerbations are at potential risk for such infections. Patients with severe COPD treated primarily with inhaled corticosteroids are considered immunocompetent. This report describes 2 cases of Aspergillus osteomyelitis with acute diskitis in apparently immunocompetent patients with COPD who, aside from brief courses of systemic corticosteroids, were using inhaled corticosteroid therapy. One patient was treated with intravenous amphotericin B alone, whereas the other received amphotericin B and underwent surgical debridement. Both have done well and were symptom free at 6-month follow-up.

Acute Disease↗
PubMed1999

Synchronization of estrus in beef cattle with norgestomet and estradiol valerate.

Fifty-six cows received a norgestomet implant and an injection of norgestomet and estradiol valerate; half (n = 28) received 500 IU equine chorionic gonadotrophin (eCG) at implant removal, 9 d later. A third group (n = 25) received 2 doses of cloprostenol (500 micrograms) 11 d apart. Estrous rate was higher (P < 0.05) for cows given norgestomet and estradiol plus 500 IU eCG (75.0%) than for those receiving cloprostenol (44.0%); for those receiving norgestomet and estradiol alone, it was intermediate (67.8%). Pregnancy rates to artificial insemination (after estrus or timed) were higher (P < 0.05) for cows given norgestomet and estradiol than for those given cloprostenol (23 of 28, 82.1% vs 13 of 25, 52.0%), and intermediate (67.8%) for those given norgestomet and estradiol plus eCG. In a second experiment, for heifers treated with norgestomet and estradiol plus eCG (n = 15) or with 2 doses of cloprostenol (n = 16), estrous rates were 66.7% vs 56.2% (P > 0.5), ovulation rates were 100.0% vs 81.2% (P = 0.08), intervals from implant removal or cloprostenol treatment to estrus were 48.0 +/- 4.4 hours vs 61.3 +/- 7.0 hours (P = 0.12) and to ovulation were 70.4 +/- 4.4 hours vs 93.2 +/- 7.5 hours (P < 0.01), respectively; pregnancy rates were 41.7 and 35.7%, respectively (P > 0.5). Norgestomet and estradiol were as good as (heifers) or superior to (cows) a 2-dose cloprostenol regimen. In cows given norgestomet and estradiol, injecting eCG at implant removal did not significantly improve estrous or pregnancy rates.

Analysis of Variance↗
PubMed1999

Ultrastructural changes on the epithelial cells of uterine tubes of Wistar rats after chronic ethanol ingestion.

The present paper describes the morphological alterations of the epithelial layer of the uterine tubes of rats submitted to experimental chronic alcoholism using anatomical, histological, ultrastructural and morphometric methods. Sixty adult rats (Rattus norvegicus albinus) at the same age (3 months) and with a mean body weight of 228 g were divided into two groups. The control group received solid diet (Purina rat chow) and tap water ad libitum. The alcoholic group received the same solid diet and was allowed to drink only sugar cane brandy dissolved in 30 degrees Gay Lussac (v/v). After periods of 90, 180 and 270 days of treatment animals at normal estrus were anaesthetised with ethyl ether, weighed and sacrificed. Subsequently, the uterine tubes were dissected, weighed and prepared for TEM and SEM methods. The final mean body weights were similar in the control and alcoholic groups. The morphometric analysis showed no difference between control and alcoholic epithelial height. The alcoholic animals showed ultrastructural alterations: intense lipid droplet and lysosomes accumulation, dilated rough endoplasmic reticulum cisternae and vacuolization in both periods of treatment. It was concluded that alcohol acts as a toxin on the epithelial layer of the uterine tubes of rats.

Alcohol Drinking↗
PubMed1999

Toxicokinetics and oral bioavailability of fumonisin B1.

The kinetics of fumonisin B1 (FB1) after single doses of 10 mg FB1/kg (po) or 2 mg FB1/kg (i.v.) were studied in male Wistar rats. Serial blood samples were obtained after p.o and i.v. administration. Liver and kidney tissue samples were also obtained after p.o administration. Plasma, liver and kidney concentrations of FB1 were determined by a reversed-phase high-performance liquid chromatographic assay using precolumn 0-phthaldialdehyde derivatisation with fluorescence detection. The FB1 plasma profile could be adequately described by a 2-compartment open model. For FB1, the elimination half-life from plasma was 1.03 h after i.v. and 3.15 h after p.o administration. The apparent volume of distribution and volume of distribution at steady state for FB1 were 0.11 and 0.072 L, respectively, after i.v. administration. The total plasma clearance of FB1 was the same for both the p.o and i.v. routes, 0.072 L/h. After the single p.o dose, FB1 was rapidly absorbed with a Tmax of 1.02 h. The maximum plasma concentration of FB1 was 0.18 microgram/mL. The p.o bioavailability of FB1 was 3.5%. The tissue concentration time data for FB1 fit a 1-compartment open model. Considerable concentrations of FB1 were found in the liver and kidney tissues. The elimination half-lives for FB1 were longer for liver (4.07 h) and kidney (7.07 h) than for plasma (3.15 h). Tissue accumulation of FB1 was evidenced by the tissue/plasma area under the concentration-time curve (AUC) ratios; the AUCtissue/AUCplasma for FB1 was 2.03 in liver and 29.89 in kidney.

Administration, Oral↗
PubMed1999

Exposure to preservatives used in the industrial pre-treatment of timber.

OBJECTIVE: The research was to survey potential dermal exposure and inhalation exposure of operators to preservative fluids used in industrial timber pre-treatment. RESULTS: Surveys in 1996-98 produced 64 data points. These were taken from 54 sites, and involved 57 timber pre-treatment process operators. Of the data, 38 related to copper chromium arsenic preservative used in vacuum-pressure processes, 19 to solvent-based preservative in double vacuum processes and 7 to water-based preservative in double vacuum processes. Treatment cycle times, preservative concentrations, treatment load sizes and quantities of preservative used per cubic metre of timber are reported. Preservative deposition patterns were similar for all treatments, with about 90% on the legs, and most of the remainder on the arms and chest. The results are quoted as mg preservative preparation (as opposed to active substance), expressed as mg per treatment cycle and mg per minute. Water-based products in vacuum-pressure processes (38 data) showed potential dermal exposure in the range 547-132,000 mg per cycle with a median value 3960 mg per cycle (median cycle time 3 h). Water-based products in double vacuum processes (7 data) showed a range 59-8750 mg per cycle with a median value 4260 mg per cycle; and solvent-based products in double vacuum processes (19 data) showed a range 7.5-449 mg per cycle with a median value 119 mg per cycle (median cycle time 1 h for double-vacuum processes). Contamination of work clothing occurred in nearly all surveys, with around 10% penetration of the preservative as estimated by a sampling patch mounted inside the operator's coveralls. Contamination was measured inside the operator's gloves in nearly all surveys. Wearing fresh gloves was found to reduce exposure to arsenic by 71% and to permethrin by 37%. Contamination on socks was measured and found to be less frequent for double vacuum than for vacuum-pressure processes. Exposure by inhalation for vacuum-pressure processes expressed as preservative, showed a range of 0.06-7.96 mg/m3, with a median value of 1.07 mg/m3, time-weighted average exposure over one or two treatment cycles. Exposure was detected in 68% of the vacuum-pressure process surveys. There was evidence for aerosol generation on transporting timber treated with water-based preservative. For double vacuum processes, two non-zero results only were found, both for water-based preservatives. Aerosols within treatment vessels were found to have dispersed 2.5 min after opening the door. Pilotstudy biological monitoring data for urinary chromium, arsenic, and permethrin metabolites are quoted with reference to creatinine. There are tentative conclusions relating to up take via the skin.

Agrochemicals↗
PubMed1999

Morphometric analysis of the endometrial epithelium of rats (Rattus norvegicus albinus) submitted to chronic experimental alcoholism.

The effects of alcohol ingestion on the epithelial layer of the uterine endometrium of rats submitted to experimental chronic alcoholism were observed by morphometric methods. Sixty adult rats (Rattus norvegicus albinus) of the same age (3 months) and weighing on average 228 g were divided into two groups. The control group received solid diet, rat chow, and tap water ad libitum. The experimental group received the same solid diet and was allowed to drink only sugar cane brandy dissolved in 30 degrees Gay Lussac (v/v). At the end of 90, 180 and 270 days of treatment, the animals at estro were anaesthetized with ethyl ether, weighed and sacrificed. The internal reproductive organs were dissected, weighed and fixed. The final mean body weights were similar in the control and alcoholic groups. The histological results showed intense atrophy of the lining epithelium of the endometrium of uterine horns in the alcoholic group. Morphometric analysis confirmed the endometrial epithelial atrophy, showing that the alcoholic group had small cytoplasmic and nuclear areas and small cytoplasmic and nuclear perimeter compared to the control group. Scanning electron microscopic images showed intense lipid droplets accumulation in the epithelial cells from alcoholic group. Therefore, we concluded that alcohol acts as a toxin on the epithelial layer of the rat endometrium.

Alcoholism↗
PubMed1998

Quantitative and ultrastructural changes in glia and pericytes in the parietal cortex of the aging rat.

The frequency of astrocytes, microglia plus oligodendrocytes, and pericytes displaying nuclei was analyzed and quantified in 160-microm-wide strips of the parietal cortex (Par1 region) from young and aged Wistar rats. The study was performed on two groups of rats aged 3-4 and 32-36 months. Quantifications of the glial cell types and pericytes were made in 1-microm-thick sections stained with toluidine blue. Ultrathin sections were also made to analyze the ultrastructural features of these cells during aging. Astrocytes and pericytes increased in number by about 20% and 22%, respectively, with age. These increases were most significant in layers II-IV and V for both cellular types. Clusters of astrocytes were common in these layers of aging rats. The ultrastructural analysis also indicated changes in all cell types that stored inclusions and vacuoles with age, which were particularly abundant in microglial cells. End-feet astrocytes and pericytes surrounding the vascular wall also contained vacuoles and inclusions, and consequently the vascular wall increased in thickness. In conclusion, the aging process increased astrocyte and pericyte populations, but not microglia plus oligodendrocyte populations, in the rat parietal cortex. Although no significant change in nuclear size could be observed in any cell type, all glial cells as well as pericytes underwent morphological ultrastructural changes. These modifications may result from the need to correct possible homeostatic imbalances during aging.

Aging↗