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Biomedical subjects

J C Lorenzo

Publications and source records attributed to J C Lorenzo.

At least 19 recordsLinked to original sources
PubMed2001

Musculoskeletal manifestations in patients positive for human immunodeficiency virus: correlation with CD4 count.

OBJECTIVE: To determine the relationship between the CD4+ lymphocyte count and musculoskeletal manifestations of human immunodeficiency virus (HIV) infection. METHODS: All patients from 1991 to 1998 who were positive for HIV with osteoarticular manifestations were reviewed retrospectively. HIV positivity was confirmed by ELISA and Western blot. CD4 count was performed by flow cytometry. RESULTS: We studied 74 patients with osteoarticular manifestations. The study group comprised 61 men (82.4%) and 13 women (17.5%) with a mean age of 34.2 years (range 17-62). Fifty-two patients were iv drug users (70.3%). Septic arthritis was present in 20 cases (23.0%), soft tissue infections in 9 cases (12.2%), spondyloarthropathies in 6 cases (8.1%), lymphomas in 9 cases (12.2%), osteomyelitis in 6 (8.1%), and 24 miscellaneous cases (32.4%). The mean CD4 count was as follows: septic arthritis 164.7 cells/mm3, soft tissue involvement 127.1 cells/mm3, spondyloarthropathies 245.8 cells/mm3, lymphoma 132.8 cells/mm3, and osteomyelitis 233.6 cells/mm3. CONCLUSION: Osteoarticular manifestations in the setting of HIV infection tend to be predominantly infectious. S. aureus is the microorganism most frequently involved. Ostearticular infections always appeared when the CD4 count was < 200 and pyomyositis and lymphoma appeared when CD4 was < 150. CD4 counts may be useful predictors to determine the type of musculoskeletal manifestation.

Adolescent↗
PubMed1999

Paclitaxel resistance in non-small-cell lung cancer associated with beta-tubulin gene mutations.

PURPOSE: The mechanisms that cause chemoresistance in non-small-cell lung cancer (NSCLC) patients have yet to be clearly elucidated. Paclitaxel is a tubulin-disrupting agent that binds preferentially to beta-tubulin. Tubulins are guanosine triphosphate (GTP)-binding proteins. Beta-tubulin is a GTPase, whereas alpha-tubulin has no enzyme activity. We reasoned that polymerase chain reaction (PCR) and DNA sequencing of the beta-tubulin gene could reveal more information regarding the connection between beta-tubulin mutations and primary paclitaxel resistance. PATIENTS AND METHODS: Constitutional genomic DNA and paired tumor DNA were isolated from 49 biopsies from 43 Spanish and six American stage IIIB and IV NSCLC patients who had been treated with a 3-hour, 210 mg/m(2) paclitaxel infusion and a 24-hour, 200 mg/m(2) infusion, respectively. Oligonucleotides specific to beta-tubulin were designed for PCR amplification and sequencing of GTP- and paclitaxel-binding beta-tubulin domains. RESULTS: Of 49 patients with NSCLC, 16 (33%; 95% confidence interval [CI], 20.7% to 45.3%) had beta-tubulin mutations in exons 1 (one patient) or 4 (15 patients). None of the patients with beta-tubulin mutations had an objective response, whereas 13 of 33 (39.4%; 95% CI, 22.8% to 56%; P = 0.01) patients without beta-tubulin mutations had complete or partial responses. Median survival was 3 months for the 16 patients with beta-tubulin mutations and 10 months for the 33 patients without beta-tubulin mutations (P =.0001). CONCLUSION: We have identified beta-tubulin gene mutations as a strong predictor of response to the antitubulin drug paclitaxel; these mutations may represent a novel mechanism of resistance and should be examined prospectively in future trials of taxane-based therapy in NSCLC.

Adult↗
PubMed1998

Benign myoepithelioma of the skin.

A case of cutaneous myoepithelioma is reported. The tumor was composed of spindle-shaped, epithelioid, and plasmacytoid (hyaline) cells. It exhibited a widespread immunoreactivity for low molecular weight keratins and protein S-100, being irregularly positive for smooth muscle actin. Ultrastructural studies of tumor cells showed a variable content of intermediate filaments, with focal densities resembling smooth muscle dense bodies. A well-developed basal lamina, pinocytotic vesicles, and some desmosomes were also observed. In spite of being accepted as an individual entity, myoepitheliomas probably belong to a family of lesions that include mixed tumors. Therefore, this case can be considered as a salivary-gland-type tumor, probably originating from myoepithelial cells of sweat glands. The existence of this unique neoplasm provides further support to the debated role of myoepithelial cells in the development of mixed tumors.

Actins↗
PubMed1997

Microsatellite alterations at 5q21, 11p13, and 11p15.5 do not predict survival in non-small cell lung cancer.

We investigated the clinical implications of allelic deletions at three common sites of loss of heterozygosity (LOH) in regions 5q21, 11p15.5, and 11p13 in 86 patients with non-small cell lung cancer (NSCLC). We performed a PCR-based microsatellite polymorphism assay for detection of LOH. The microsatellite markers used were D5S82 (proximal to the APC gene), MCC (within the MCC gene), D11S904 (11p13), HRAS (within the H-ras gene), and D11S860 (11p15.5). Of the 68 informative cases at 5q21 loci, LOH was found in 14 cases (20%), whereas LOH frequency in 11p15.5 and 11p13 was 31% (19 of 61 informative cases) and 19% (12 of 63 informative cases), respectively. There was a significant correlation between 5q21 LOH and mediastinal lymph node involvement (P = 0.03). However, no differences were observed in median survival times (26 months in patients with 5q21 LOH versus 37 months in the remainder; P = 0.33) nor in patients with 11p LOH (38 months versus 32 months, respectively; P = 0.72). Cox's proportional hazards model predicted that stage was the only independent poor prognostic marker in the entire cohort of NSCLC patients. Thus, the present study revealed two important abnormalities, LOH at chromosome 5q21 and LOH at chromosome 11p, both implied in NSCLC development.

Adult↗
PubMed1996

Bone bacillary angiomatosis in an HIV-infected patient.

Bacillary angiomatosis (BA) is a recently discovered multisystem bacterial infectious disease seen in the setting of immune suppression due to the human immunodeficiency virus (HIV). A case of an HIV-infected patient with osteolytic bone involvement is reported.

Adult↗
PubMed1995

Fibrin glue is a sealant and not a nerve barrier.

This experimental work on the internal popliteal nerve of the rabbit was undertaken to clarify whether interposition of a block of 4 mm of fibrin-sealant would form a barrier which stops or interferes with the passage of the axons. Twenty-four adult rabbit tibial nerves were placed in a microclamp, sectioned, and separated 4 mm. The gap between the two nerve ends was filled with fibrin sealant. Eight weeks after the procedure, the animals were sacrificed and the nerves removed. Histologic studies and morphometric longitudinal and transverse examination by image analysis showed that interposition of the block of fibrin sealant between the nerve ends was not a barrier or obstacle to the passage of axons. The use of fibrin sealant is a relatively good experimental model for a chamber of regeneration, because 70 percent of axonal regeneration was obtained.

Animals↗
PubMed1994

[Pubertal idiopathic gynecomastia].

14 boys with pubertal gynecomastia, aged 9 to 16 years, were presented. Physical assessment, including pubertal maturation, height, weight, bone age, pubic hair stage, testicular and penis calibre and degree of gynecomastia was determined. Sexual steroids, LH-FSH, prolactin, were studied. All patients had psychological stress. 11 patients had been treated surgically by mastectomy with success.

Adolescent↗
PubMed1992

Sterile transient neonatal pustulosis is a precocious form of erythema toxicum neonatorum.

A sterile pustular skin eruption was observed in 17 of 3,541 newborn infants examined over a period of 30 months. The skin eruption was always present at birth and fulfilled the clinical criteria of transient neonatal pustular melanosis (TNPM). However, some days after birth, all of them but 1 developed skin lesions typical of erythema toxicum neonatorum (ETN). Histological examination of 11 biopsies obtained at the age of 1 day showed intracorneal neutrophilic pustules in 4 and subcorneal intraepidermic eosinophilic pustules in 7. On the basis of our findings and a literature review we consider that a clear-cut differentiation between TNPM and ETN is not always possible. We propose the name sterile transient neonatal pustulosis to unify these conditions.

Diagnosis, Differential↗
PubMed1981

The morbid anatomy of the skeleton in osteogenesis imperfecta.

Clinically, the two most prominent features of osteogenesis imperfecta are dwarfing and bone fragility. Radiologic examination reveals severe osteopenia with or without multiple deformities. Histological examination of samples obtained from 16 iliac crest biopsies compared with 21 age-matched controls revealed a significantly diminished amount of bone matrix without an associated decrease in the number of bone cells, suggesting a quantitative deficiency of collagen production. Radiologic studies of 46 affected children and autopsy studies of two children revealed abnormalities in the ossification of the secondary centers of ossification, together with evidence of fracture and fragmentation of the epiphyseal growth plates causing a characteristic radiologic appearance which may be likened to a bag of popcorn. These epiphyseal abnormalities may contribute to the limb shortening in some cases.

Bone and Bones↗
PubMed1980

Giant-cell reparative granuloma of short tubular bones of the hands and feet.

Eight cases of giant-cell reparative granuloma were encountered in the short tubular bones of the hands and feet. This entity was originally described by Jaffe as a jaw lesion. Subsequently the lesion was found in the skull and facial bones. The name "giant cell reaction" was applied to similar lesions found in the short tubular bones of hands and feet. Thirteen prior cases have been reported and none recurred. Of the eight new cases described herein, four have recurred one or more times, requiring further treatment. No association with hyperparathyroidism was found. We prefer to designate these lesions as giant cell reparative granulomas of extragnathic sites. Because of overlapping ultrastructural and light-microscopic features, as well as similar biologic behavior, we feel that aneurysmal bone cyst and these giant-cell reparative lesions represent related responses to intraosseous hemorrhage.

Adolescent↗
PubMedDate not supplied

The subtalar joint: embryology and morphology.

Several different aspects of the subtalar joint are studied. Embryology indicates that it is a recently acquired structure. The anterior subtalar joint does not have a uniform morphology, and it has been subdivided into three anatomical descriptions (ovoid, bean, and two part). To correct the confusion found in other papers, we intend to clearly describe the anatomy of the ligaments. The form and function of the retinacula, cervical ligament, and ligament of the canal are studied. The microscopic anatomy of ligaments is studied, dealing specifically with their innervation and the structure of their fibers.

Ankle Joint↗