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Biomedical subjects

J Lucas

Publications and source records attributed to J Lucas.

At least 55 records · Page 3Linked to original sources

Upper-gastrointestinal bleeding from angiodysplasia of the minor papilla.

Angiodysplasia is an often unrecognized cause of upper-gastrointestinal bleeding, most commonly found in the antrum of the stomach but also in the duodenum and rarely in the esophagus. Small-intestinal angiodysplasia is the source of gastrointestinal bleeding of obscure origin in 30-40% of cases. The diagnosis is usually made by esophagogastroduodenoscopy, push enteroscopy, or selective angiography. We report the first case of angiodysplasia of the minor papilla diagnosed by side-viewing duodenoscopy.

Aged↗

Lung resection in cystic fibrosis patients with localised pulmonary disease.

The results of lobar resection to treat severe localised bronchiectasis in six children with cystic fibrosis are described. Sustained clinical improvements occurred in children undergoing this surgical approach to treatment. Detailed assessment and intensive preoperative and postoperative medical treatment are essential to a favourable outcome in carefully selected patients.

Bronchiectasis↗

Cytogenetic analysis of BC2, a new human hepatoma cell line, by fluorescent in situ hybridization.

Cytogenetic analysis of a new human hepatoma cell line BC2 was performed with conventional cytogenetic techniques and fluorescent in situ hybridization. Numerical and structural abnormalities were observed by conventional cytogenetics for chromosomes 1, 2, 4, 7, 8, 9, 10, 11, 15, 17 and 20. Chromosome painting allowed to specify the translocation of chromosome 1, and to characterize 3 markers from chromosome 8 and one marker from 9, which were unrecognizable by conventional techniques. Comparison of chromosome 1 abnormalities with those reported in the literature for other human hepatoma cell lines showed that structural abnormalities of chromosome 1 were present in different regions of this chromosome. A review of the literature was done, and the results discussed, suggesting that alterations of chromosome 1 may be important in hepatocarcinogenesis.

Carcinoma, Hepatocellular↗

Opitz GBBB syndrome: chromosomal evidence of an X-linked form.

BBB syndrome and G syndrome were originally reported as distinct X-linked disorders. Clinical studies indicated that BBB and G syndromes were likely to represent variant expression of the same disorder, now referred to as "Opitz" GBBB syndrome. Several occurrences of male-to-male transmission in both syndromes led to the hypothesis that GBBB syndrome was a single autosomal dominant, sex influenced disorder, now tentatively mapped to 5p12-13. We report on a large pedigree in which GBBB syndrome appears to cosegregate with a pericentric inversion of the X chromosome inv(X)(p22.3q26). It indicates the possible existence of a true X-linked form of GBBB syndrome, which does not appear phenotypically different from its autosomal counterpart. The gene could map in the vicinity of the breakpoints, in Xp or Xq. The existence of two genes affecting a common pathogenetic pathway could explain the gender-dependent expressivity of GBBB phenotype.

Abnormalities, Multiple↗

Platelet activating factor activates MAPK and increases in intracellular calcium via independent pathways in B lymphocytes.

Platelet activating factor (PAF)-stimulation of human B-lymphoblastoid cells results in the activation of microtubule associated protein 2-kinase (MAPK) and increases in intracellular calcium. Although increases in intracellular calcium induce MAPK activation in these cells, PAF can stimulate MAPK activation in the absence of detectable changes in intracellular calcium concentrations ([Ca2+]i). Treatment of the LA350 B-lymphoblastoid cell line with either pertussis toxin (PT) or cholera toxin (CT) blocked PAF-induced changes in [Ca2+]i. However, only PT blocked PAF-induced activation of MAPK as determined by shifts in the mobility of MAPK on immunoblots. In support of this finding, only PT but not CT blocked PAF-induced phosphorylation and activation of p90rsk, an event thought to be distal to MAPK activation. These results suggest that the PAF receptor is mediating MAPK activation through pathways separate from those mediating increases in intracellular calcium.

B-Lymphocytes↗

Correlation of MR imaging and pathologic findings in athletes undergoing surgery for chronic patellar tendinitis.

OBJECTIVE: Jumper's knee, or chronic patellar tendinitis, can be a source of considerable pain in athletes. The changes that occur with shearing of the tendinous fibers from repeated microtrauma can progress to significant degeneration and increase the risk of tendon rupture. In order to better understand this phenomenon, a correlative study relating the MR imaging and pathologic findings was performed. SUBJECTS AND METHODS: Nine high-performance athletes 18-22 years old (mean age, 20 years) underwent operation of 11 knees for long-standing jumper's knee. The average period of symptoms was 3 years (range, 2 to 6 years). MR knee examinations were performed before surgery in all athletes. The symptoms, MR findings, and pathological findings were correlated. RESULTS: There was focal thickening in the proximal one third of the patellar tendon (range, 9-16 mm; mean, 12 mm) in all 11 knees, involving the medial portion of the tendon in 10 and the center in one. On proton-density-weighted MR images, all knees demonstrated a focus of abnormal signal intensity in the proximal one third of the patellar tendon. On T2-weighted MR images, 10 knees demonstrated abnormal signal intensity; eight were isointense to that seen on proton-density-weighted images, and two were relatively hyperintense. Ten tendons demonstrated a poorly defined posterior margin. Pathologically, the areas of abnormal signal intensity corresponded to tissue containing tenocyte hyperplasia, prominent angiogenesis with endothelial hyperplasia, loss of longitudinal collagenous architecture, and microtears with collagen fiber separation. Hyaline degeneration was present in specimens from every patient. CONCLUSION: In athletes with chronic patellar tendinitis, areas of abnormal signal intensity on MR imaging corresponded to degenerative pathologic changes consistent with angiofibroblastic tendinosis. In nearly all patients, the tendon thickening occurred eccentrically. Disproportionate medial tendon thickening may be related to unequal tensile forces across the knee joint, resulting in greater stress on the medial portion of the extensor mechanism of the knee.

Adolescent↗

Integrating outcomes measurement into clinical practice improvement across the continuum of care: a disease-specific episode of care model.

This article describes a model for incorporating outcomes measurement into a comprehensive, continuum-wide clinical practice improvement program developed at Lovelace Health Systems (Albuquerque, N.M.). Created in 1993, the Lovelace Episode of Care Program currently includes nine disease-specific multidisciplinary teams that are working to improve care by addressing such issues as severity, appropriateness, efficiency, continuous quality improvement indicators, practice guidelines, care maps, and outcomes. Key features and advantages of the model are discussed, as well as implementation issues, successes, lessons learned, program restructuring and improvement, and applicability of the framework across diseases and health organizations.

Comprehensive Health Care↗

[Antiphospholipid antibodies in women with habitual abortions. Treatment with prednisone and acetylsalicylic acid during pregnancy].

PURPOSE: To discover the prevalence of antiphospholipid antibodies in women with a history of repeated miscarriages. Therapy evaluation of aspirin and prednisone to achieve living term foetus from women in whom antiphospholipid antibodies had been detected and who had become pregnant again. PATIENTS AND METHODS: 82 consecutive women with history of at least of two miscarriages, with no live foetus in either case. 14 women positive for antiphospholipid antibodies who had become pregnant again (group of therapy evaluation), were treated with aspirin (125 mg/d) and prednisone (20 mg/d). 60 normal pregnant women (control group). Lupus anticoagulant evaluation: APTT tests caolin clotting time and APTT system neutralized with platelet phospholipids. Antiphospholipid antibodies: ELISA test. RESULTS: 13.4% were positive to antiphospholipid antibodies (ELISA), and 2.4% were positive in both positive in both test. Therapy evaluation: 75.5% (11 cases) of pregnancies were successful (normal foetus), 14% (2 cases) of fetal losses, and 7% (1 case) of foetal malformations (acranius). CONCLUSIONS: In our study the antiphospholipid antibodies represent one of the main causes of repeated foetal losses. We recommended in cases of infertile women to test for antiphospholipid antibodies regularly. We confirm the effectiveness of the therapy (aspirin and prednisone) in achieving successful pregnancies in patients with a history of infertility.

Abortion, Habitual↗

Expression of multiple neuregulin transcripts in postnatal rat brains.

The distribution of neuregulin transcripts in rat brains was studied by both RNA blotting and in situ hybridization. Our data demonstrate that multiple neuregulin transcripts are expressed in neurons of the basal forebrain, the hippocampus, the diencephalon, the cerebellum, the brainstem, and the spinal cord. Developmental changes in the distribution of neuregulin transcripts were observed only in the cerebellum and the hippocampus. The intense neuregulin hybridization signals in the brainstem motor and sensory nuclei and the spinal motor neurons are suggestive of a functional involvement of neuregulins in motor and sensory systems. The expression of neuregulins in other parts of the brain also indicates that these factors are involved in a variety of central nervous system functions.

Animals↗

Turner's syndrome with X-isochromosome and Hashimoto's thyroiditis.

OBJECTIVE: The higher frequency of Hashimoto's thyroiditis in Turner's syndrome compared with the general population is well known. We have attempted to establish clearly the more frequent association of thyroiditis with the X-isochromosome, since previous reports of this aspect have included only small numbers of patients. DESIGN: Retrospective study of patients with Turner's syndrome investigated within the past 12 years. PATIENTS: Sixty-seven cases of Turner's syndrome were reviewed. MEASUREMENTS: Peripheral blood leucocyte karyotype and screening for thyroid disturbances on the basis of clinical examination and laboratory evaluation (anti-thyroglobulin and anti-microsomal antibodies, basal TSH levels and TSH levels after TRH stimulation) were made for each patient. RESULTS: A diagnosis of thyroiditis, based on the association of positive antibody titres, elevated TSH and an abnormal thyroid gland on clinical examination, was established in 20.9% (14/67) of cases. A significantly higher frequency of thyroiditis was found among the patients presenting with an X-isochromosome (57.3%, 9/16), compared to patients with other karyotypes (9.8%, 5/51) (P = 0.0001). CONCLUSIONS: Our results, obtained by investigation of a larger number of patients with an X-isochromosome karyotype than in previous reports, confirm conclusively that patients with X-isochromosome Turner's syndrome have an increased risk of developing thyroiditis.

Adolescent↗

Thermal balance and metabolic rate during upper respiratory tract infection in infants.

Sequential recordings were made in the first five months after birth of metabolic rate, environmental temperature, and body temperature during sleep at home in 17 infants, each with an older sibling. Further recordings were made whenever an older sibling developed an upper respiratory tract infection (URTI), again four to six days later, and again two weeks later, aiming to achieve recordings before, during, and after an URTI in the infant. The temperature of the room and wrapping of the infant were determined according to their usual practice by the parents. Parents added appropriate wrapping to achieve thermal neutrality based on our calculated values and the measured oxygen consumption. In five of the six infants who developed an URTI in the first three months after birth there was no change or a decrease in metabolic rate at the time of the infection; for infants older than 3 months the metabolic rate increased in three of the five episodes recorded. Peripheral skin temperature decreased at the time of URTI at all ages, though in the older infants it usually increased in parallel with rectal temperature during the latter part of the night, when pyrexia was most common. Infants thus respond to URTI by heat conservation. In the younger infants the lower metabolic rate and the further decrease in this rate with URTI means that fever is rare, and their temperature may decrease on infection. In the older infants the increase in metabolic rate (from an already higher baseline) may result in fever. These differences may contribute to the increased vulnerability of the older infants to heat stress, particularly at the time of acute viral infections.

Acute Disease↗

Effect of magnetic susceptibility contrast medium on myocardial signal intensity with fast gradient-recalled echo and spin-echo MR imaging: initial experience in humans.

PURPOSE: To show the effect of dysprosium diethylenetriaminepentaacetic acid bis-methylamine injection on the images of normal human myocardium. MATERIALS AND METHODS: T2-sensitive fast gradient-recalled echo (GRE) (repetition time [TR], 10.8 msec; echo time [TE], 4.2 msec) and spin-echo (SE) (TR, three RR intervals; TE, 60 msec) magnetic resonance (MR) imaging with driven equilibrium-preparation pulse was used to produce T2 contrast material enhancement. The contrast agent was injected into 12 healthy subjects at doses of 0.05, 0.1, 0.2, 0.4, and 0.6 mmol/kg. RESULTS: Driven equilibrium-prepared GRE images showed a transient decrease of myocardial signal intensity at doses of 0.2-0.6 mmol/kg. Postcontrast T2-weighted SE images showed a myocardial signal attenuation (30%-45% decrease) at a dose of 0.4 mmol/kg or higher. CONCLUSION: Dynamic MR imaging with a magnetic susceptibility contrast medium can be used to monitor the first pass of contrast media through human myocardium with a conventional MR imager and a fast GRE sequence.

Adult↗

Neuroblastoma sensitivity to growth inhibition by deferrioxamine: evidence for a block in G1 phase of the cell cycle.

Iron (Fe) is known to be necessary for cellular proliferation. Previous studies have suggested that neuroblastoma cells appear to be relatively sensitive to growth inhibition by a specific Fe chelator, deferrioxamine (DFO), in vitro. Also, DFO has been recently used for the treatment of neuroblastoma patients. In this paper we demonstrate that neuroblastoma cell proliferation in vitro is extremely sensitive to inhibition by DFO as compared to another cell line with almost identical growth kinetics. Neuroblastoma cells treated with DFO adapt appropriately to Fe chelation as measured by marked upregulation of transferrin receptor mRNA, increased functional transferrin receptor, and decreased cellular ferritin concentration. Further studies that quantitated cellular incorporation of 59Fe from added transferrin-59Fe in the presence of DFO indicated that neuroblastoma cells were more sensitive to inhibition of Fe incorporation by the chelator as compared to the other cell line. Neuroblastoma cells treated with DFO showed a consistent arrest in the G1 phase of the cell cycle. For cells taken from the "resting" state this block occurred before the vast majority of cells had entered S or G2-M phases of the cell cycle. Further evidence that neuroblastoma cells were arrested before the G1-S interface was provided when cells inhibited by DFO and released into aphidicolin exhibit arrest at the G1-S interface, whereas release from aphidicolin into DFO resulted in entry into S phase. Also, DFO-treated cells exhibited a decrease in both p34cdc2 immunoreactive protein as well as kinase activity. The results of these latter studies strongly indicate evidence for a Fe requirement for malignant cell proliferation before the onset of DNA synthesis. Our results also provide a basis for further studies that will better define a therapeutic approach to patients with neuroblastoma utilizing DFO treatment.

Aphidicolin↗

The effects of structural analogs of putrescine on proliferation, morphology and karyotype of glioblastoma cells in culture.

In a previous study, we identified regions on the surface of tumor cells which act as acceptor sites for putrescine (Put) and studied the competition between structural analogs of Put (N,N'-tetramethyl-alpha,omega-diaminoalkanes) and Put bound to latex microspheres. A chain of four to seven carbons was necessary for inhibition of Put-latex binding to the cell surface of human glioblastoma (U251) cells. We show here that under the experimental conditions, N,N'-tetramethyl-1,4-butanediamine and N,N'-tetramethyl-1,7-heptanediamine exhibit an antitumor effect. In a first step (1-48 h after treatment), cells exposed to these compounds show large intracellular vacuoles. We failed to detect any acid phosphatase activity in these intracellular structures revealing that they were not lysosomes. Electron microscopy observations argue for the conclusion that these vacuoles are an hypertrophy of the endoplasmic reticulum (ER) and/or of the Golgi vesicles. Our hypothesis is that this typical effect of the analogs reveals that ER could be a physiological target of endogenous polyamines. At a later stage (6 days after treatment), the cells undergo morphological and biochemical changes: thin and long expansions characterize the cells and the GFA protein is overexpressed. Correlated to both these effects, karyotypic modifications are found in chromosomes 3 and 6. These changes evoke a differentiation of the treated cells. The work provides evidence that N-methylated polyamine analogs taking the place of endogenous putrescine demonstrate a hopeful antitumor effect.

Cell Differentiation↗