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Biomedical subjects

L Costa

Publications and source records attributed to L Costa.

At least 73 records · Page 4Linked to original sources
PubMed1995

Serological characterisation and antimicrobial susceptibility of Actinobacillus pleuropneumoniae strains isolated from pigs in Spain.

Seventy-one isolates of Actinobacillus pleuropneumoniae isolated from the lungs of pigs in outbreaks of pleuropneumonia in Spain were serotyped by indirect haemagglutination. Serotype 4 (42.2 per cent), serotype 7 (22.5 per cent) and serotype 2 (12.8 per cent) were predominant, whereas serotypes 1, 3, 6, 8, 9, 12 and untypable isolates were present only in small numbers. Serotypes 1, 2, 4 and 7 originated mainly from cases of acute pleuropneumonia, whereas serotypes 3, 6, 8, 9 and 12 were associated with chronically infected herds. The susceptibility of the isolates to 20 antimicrobial agents was determined by agar disc diffusion. Most were susceptible to cefuroxime, cefaclor, cefazolin, kanamycin, tobramycin, gentamicin, oxolinic acid, ciprofloxacin, enoxacin, thiamphenicol, colistin and trimethoprim/sulphamethoxazole. Marked resistance was found with amoxicillin, ticarcillin, oxytetracycline, doxycycline and metronidazole. Rifampicin, fosfomycin and tiamulin were the agents most effective against the isolates tested.

Actinobacillus Infections↗
PubMed1995

Biochemical markers of bone turnover in patients with metastatic bone disease.

Several biochemical markers of bone formation and bone resorption have recently been developed. These markers have been evaluated for clinical utility in patients with metabolic bone disease, including Paget disease and osteoporosis, and for their potential use in cancer patients whose disease has metastasized to bone. We have evaluated seven markers of bone turnover in the plasma and urine of 94 patients with newly diagnosed or progressive malignancy with and without clinical evidence of bone metastases. As determined by a positive bone scan and (or) bone survey, 30 patients had metastases to bone; 51 patients had metastatic cancer without overt bony involvement; and 13 patients had local disease without bone metastases. To evaluate the predictive value of these markers in the metastatic population, we utilized a "Z-score" and logistic regression analysis to distinguish patients with documented bone metastatic disease from those patients without clinical evidence of bone metastases. The higher the Z-score, the better the marker predicts the presence of bone metastases. With this statistical approach, urine N-telopeptide measurements had the highest Z-score and the most significant association with the probability of bone metastases. Urine deoxypyridinoline was the second most predictive marker of bone metastases. Thus, biochemical markers of bone resorption might be of use to predict the presence of bone metastases in cancer patients and to monitor the efficacy of antiresorptive therapy in patients treated for metastatic bone disease.

Alkaline Phosphatase↗
PubMed1995

Bone markers in osteoporosis and malignancy.

Normal bone turnover is characterized by a balance (coupling) between the formation of new bone by osteoblasts and the resorption of old bone by osteoclasts. This bone remodeling takes place at discrete sites in the skeleton called bone remodeling units. Initially, the cells that line bone are replaced by osteoclasts that bring about resorption of the surface of bone. Next, osteoclasts are replaced by osteoblasts that gradually refill this space. This balance between bone formation and bone resorption is altered in most metabolic bone diseases (uncoupling). Over the past two decades many investigators have attempted to develop both sensitive and specific assays for the noninvasive assessment of bone turnover. Biochemical markers of bone formation include total and bone-specific alkaline phosphatase, serum osteocalcin (bone gla protein), and more recently procollagen I extension peptides. During the extracellular processing of type I collagen, there is a cleavage of the aminoterminal (p-coll-I-N) and carboxyterminal (p-coll-I-C) extension peptides prior to fibril formation. These peptides circulate in blood and could be useful markers of bone formation.

Alkaline Phosphatase↗
PubMed1994

Immunoaffinity purification of recombinant hepatitis B surface antigen from yeast using a monoclonal antibody.

A murine monoclonal antibody developed for the purification of recombinant hepatitis B surface antigen was immobilized on a chromatographic support and used to adsorb and purify the recombinant antigen from yeast. The adsorption-elution behaviour was first investigated using monoclonal antibody-coated enzyme-linked immunosorbent assay plates and performing adsorption, washing and elution procedures with different elution agents. It was found that 3 M KSCN and 8 M urea at neutral pH disrupted antigen-antibody interactions in both systems. The procedure for washing the immunoaffinity column was optimized, using different salts and detergents. The best results were obtained by applying the starting material in 1 M NaCl and washing with the same buffer. The use of 0.1% sodium deoxycholate in the washing buffer reduced about 20-fold lipopolysaccharide contamination in the eluates as compared with washing without detergent. The relationship between bed height and the adsorption capacity of the column was studied, and it was found that the dynamic capacity decreased twice on reducing its length/diameter ratio tenfold. The recovery of antigen was not affected by increasing the flow-rate up to 25 cm/h but decreased at higher values. Using the optimum conditions, the affinity column was able to purify the recombinant hepatitis B surface antigen to more than 90% purity and a 65% antigen recovery was obtained.

Animals↗
PubMed1994

Enhancement of EIAV replication and disease by immunization with a baculovirus-expressed recombinant envelope surface glycoprotein.

The potential for antibody-dependent enhancement of replication of macrophage/monocyte tropic viruses has posed a significant problem in the development of vaccines for several animal and human viruses and has raised significant concern in the design of potential AIDS vaccines. Using the previously described equine infectious anemia virus/Shetland pony system as a model for HIV-1 vaccine development, we have evaluated the efficacy of a recombinant subunit vaccine containing a baculovirus-expressed envelope surface glycoprotein (gp90) of EIAV. The results of these trials demonstrate not only that the recombinant vaccine failed to protect against infection by standard homologous and heterologous EIAV challenge strains, but that it resulted in a marked enhancement of virus replication and exacerbation of disease in immunized ponies exposed to the heterologous virus strain. Thus, the recombinant EIAV gp90 vaccine provides a novel in vivo model for examining in detail the mechanisms of immune enhancement of a lentivirus infection and for evaluating strategies to avoid the production of deleterious immune responses in AIDS vaccine design.

AIDS Vaccines↗
PubMed1993

Phase I-II intraperitoneal mitoxantrone in advanced pretreated ovarian cancer.

36 previously treated patients (25 with anthracyclines) with advanced epithelial ovarian cancer have been treated with intraperitoneal (i.p.) mitoxantrone (M) at increasing doses. The response was evaluated through repeated laparoscopy with multiple biopsies and serial measurement of Ovarian Cancer Antigen 125 (CA 125); 11/36 patients had a complete (6 patients) or partial (5 patients) response. Toxicity (both local and general) was observed starting from 25 mg/m2 of M per cycle. The amount of drug reaching systemic circulation was monitored by measuring M plasma value after i.p. treatment. This study showed wide variations in serum levels obtained after i.p. doses ranging from 23 to 36 mg/m2. The area under the curve (AUC) of mitoxantrone plasma samples, did not correlate with the i.p. administered dose. Conversely, a correlation seems to exist between the plasma AUC and the responder status. Patients who showed clinical responses to i.p. treatment with mitoxantrone had AUCs and plasma peak levels of the drug that were significantly higher than those in non-responders (P = 0.03, Fisher's exact test).

Adult↗
PubMed1993

Risk of preneoplastic and neoplastic events in operated oral leukoplakias.

We retrospectively analysed 167 consecutive patients with oral leukoplakias operated on by CO2 laser resection in the Day Hospital of the Istituto Nazionale Tumori in Milan from January 1981 to December 1988, with post-operative histological examination negative for cancer. Within 5 years there were 69 patients with at least one unfavourable event. First unfavourable events were: 31 local relapses, 27 new leukoplakias, 5 oral carcinomas and 6 other neoplasms elsewhere. To identify possible prognostic factors we recorded age, sex and history of previous oral leukoplakias or head and neck cancers; also number, site, size and type of lesion; as well as tobacco and alcohol consumption and oral hygiene. The Cox regression model was employed to compare disease-free survival between different patient groups, both by univariate and multivariate analysis. From this analysis it emerges that age of operated patients and size of resected lesion are significantly predictive for development of relapses, new leukoplakias and carcinomas.

Adult↗
PubMed1993

[Disodium pamidronate (APD) in the treatment of bone metastases].

Diphosphonates are potent inhibitors of bone resorption, they have been evaluated in several clinical trials for bone metastases. We performed a clinical study to evaluate the therapeutic effect of Disodium Pamidronate over pain and radiologic evolution in bone metastases (Breast Cancer and Multiple Myeloma patients). The results regarding the first 10 patients concluded that there is good drug tolerability and significant analgesic activity in 6 patients, with sclerosis of lytic skull lesions in one breast cancer patient.

Adult↗
PubMed1992

Pure alexia and right hemiachromatopsia in posterior dementia.

A 66 year old, right handed woman presented with pure alexia and right hemiachromatopsia (PARH) in the context of a posterior dementia. PARH was accompanied by prosopagnosia, 2-D object agnosia, and environmental agnosia. Visual fields were normal to confrontation testing. The pathological anatomy of PARH involves circumscribed damage to the lingual and fusiform gyri and paraventricular white matter of the left occipital cortex, two contiguous cortical regions functionally specialised for processing colour and word form information, respectively.

Aged↗
PubMed1991

CO2 laser surgery in laryngeal cancers: three year results.

The purpose of this paper is to evaluate the relapse-free survival and the overall survival at three years of 39 laryngeal cancers (10 T1 and 29 small recurrent carcinomas with mobile vocal cord) operated on by CO2 laser surgery at the Istituto Nazionale Tumori in Milan from 1982 to 1987. The 10 patients with T1 cancers had two local recurrences, whereas the 29 patients with recurrent carcinomas had 14 local recurrences. Local relapses occurred in 2/16 patients with cancer limited to the vocal cord and in 9/17 patients with glottic tumors extended to the anterior commissure or to the ventricular band or to the arytenoid. Supraglottic cancers recurred in 3/4 patients. The authors conclude that transoral laser surgery is an effective modality for treatment of T1 primary and small recurrent carcinomas of the larynx, when limited to the middle third of the vocal cord.

Adult↗