Search PubMed⌕ Search

Biomedical subjects

C Garcia

Publications and source records attributed to C Garcia.

At least 145 records · Page 8Linked to original sources
PubMed1996

The Latin American trial of psychosocial support during pregnancy: effects on mother's wellbeing and satisfaction. Latin American Network For Perinatal and Reproductive Research (LANPER).

A randomized controlled trial including 2235 women at high risk of low birthweight was conducted in four Latin American institutions. The objective of this trial was to evaluate a psychosocial support intervention during pregnancy aimed at improving perinatal health and mothers' psychosocial conditions. The core of the intervention was four to six home visits where emotional support, counseling and strengthening of the woman's social network was provided. Outcomes were measured at 36 weeks of pregnancy, post-partum and 40 days after delivery. The intervention was not successful in either altering women's perception of social support and satisfaction with the reproductive experience, as well as maternal and newborn's health care. It is concluded that although high levels of psychosocial distress during pregnancy may play an independent role in determining adverse pregnancy outcomes, this adverse effect does not appear to be ameliorated by psychosocial interventions conducted only during pregnancy, particularly those of a magnitude that can be realistically implemented (in content and frequency) at public care services in most developing countries.

Adolescent↗
PubMed1996

Pharmacological modulations of adrenergic phenotype in medullary C2 and C3 cell groups of adult rat.

The adrenergic phenotype was analysed in the rat's rostral dorsomedial medulla under normal conditions and 3 days after a single intraperitoneal injection of an eburnamine derivative, RU 24722, which increases tyrosine hydroxylase protein expression in the rostral portion of the nucleus tractus solitarius. This approach was investigated by a double immunofluorescence labelling of tyrosine hydroxylase and phenylethanolamine N-methyltransferase proteins. Under normal conditions, most adrenergic cell bodies are anatomically distributed in the dorsal and rostral medulla oblongata between the rostral part of the dorsal motor nucleus of the vagus nerve and the medial longitudinal fasciculus. Adrenergic neurons detected in this medullar region were distributed between both cell groups. Three days after the pharmacological RU 24722 treatment, an upregulation in tyrosine hydroxylase and phenylethanolamine N-methyltransferase protein expression was detected in both cell groups characterized by a highly increased number of tyrosine hydroxylase- and phenylethanolamine N-methyltransferase-containing cell bodies. The number of TH-mRNA containing neurons was also increased, indicating the transcriptional level of this regulation. These results demonstrated a particular neuronal plasticity of adrenergic phenotype in the medullary cell groups of adult rat.

Analysis of Variance↗
PubMed1996

Autoradiographic localization of vasopressin V1a receptors in the rat kidney using [3H]-SR 49059.

Localization and characterization of binding sites of the selective non-peptide vasopressin receptor V1a ligand, [3H]-SR 49059, were investigated in the adult rat kidney by quantitative autoradiography using a fast-detecting radioluminographic phosphor-imaging plate system. [3H]-SR 49059, like the other V1a ligands used, showed a total absence of binding in the papilla, discrete and sparse labeling in the cortex and maximal binding in the outer part of the inner medulla. This labeling seemed to be mainly associated with medullary interstitial cells and vascular elements of the vasa recta. Conversely, [3H]-AVP intensely labeled the V2-enriched medulla-papillary portion of the kidney and, to a lesser extent, the cortical structures. [3H]-SR 49059 binding, quantified in the outer part of the inner medulla in rat kidney sections, was time-dependent, reversible, saturable and a single class of high affinity binding sites (Kd = 1.48 +/- 0.16 nM) was identified. The relative potencies of the reference peptide and non-peptide compounds to inhibit [3H]-SR 49059 binding confirm the V1a nature of the site and the stereospecificity of this binding. Thus, [3H]-SR 49059 allows the mapping and characterization of the V1a receptor population present in the rat kidney. The stability and the highly selective affinity of this non-peptide ligand for rat and human V1a receptors make it a suitable probe for the localization of V1a receptors in organs expressing heterogeneous populations of receptors.

Animals↗
PubMed1996

Case report: polymyositis-induced myoglobinuric acute renal failure.

Polymyositis rarely leads to myoglobinuric acute renal failure. One such case is reported here, and certain common features in reported cases are discussed. Given therapeutic advances, these patients should do well despite the dismal prognosis reported in the literature, but early diagnosis and prompt treatment are essential.

Acute Kidney Injury↗
PubMed1996

Ultrastructural distribution of PMP22 in Charcot-Marie-Tooth disease type 1A.

Peripheral Myelin Protein-22 (PMP22) is a membrane glycoprotein which represents up to 5% of total protein in myelin of peripheral nerves. Mutations affecting the PMP22 gene have been linked to the inherited peripheral neuropathies Charcot-Marie-Tooth disease type 1A (CMT1A; duplications and point mutations), Dejerine-Sottas syndrome (DSS; point mutations), and hereditary neuropathy with liability to pressure palsies (HNPP; deletions). In this study, we determined the ultrastructural distribution of PMP22 and other myelin proteins in normal human peripheral nervous system (PNS) nerves and in CMT1 patients with or without the CMT1A duplication on chromosome 17. Our results demonstrate that PMP22, P0 protein, and myelin basic protein are present in compact myelin of all patients examined. PMP22 was also present in the plasma membrane of Schwann cells of unmyelinated fibers and onion bulbs. Although the precise biological role of PMP22 remains to be discovered, our results support the hypothesis that this protein serves multiple functions in Schwann cells.

Charcot-Marie-Tooth Disease↗
PubMed1996

Influence of cryopreservation on the sensitivity of human islets to tumor necrosis factor.

Tumor necrosis factor (TNF alpha) has been shown to inhibit insulin release and it has been postulated to-be an important effector in islet rejection. We studied the effect of cryopreservation on glucose oxidation rate (GOR), lipid synthesis, hormone secretion (insulin, glucagon, somatostatin, thyrotropin-releasing hormone), and cyclic guanosine 3',5'-monophosphate (cGMP) content of human islets, in the presence or absence of TNF alpha, looking for changes that could explain a different susceptibility to rejection for cryopreserved islets. Islets were isolated from multiple organ donor pancreata by collagenase digestion. The islets were then cultured for 7 days, cryopreserved (-0.25 degrees C/min), and stored in liquid N2. After 24 h of culture, thawed islets were cultured for an other 24 h in the presence or absence of TNF alpha. Islets were then washed to remove the cytokine and incubated in Krebs-Ringer bicarbonate (5 or 20 mM glucose), and both the cGMP content of the islets and the hormone concentration in the medium were determined by radio-immunoassay. GOR was measured as the production of 14CO2 from 5 or 20 mM D-[U-14C]glucose, and de novo lipid synthesis was determined as D-[U-14C]glucose incorporation into different lipidic fractions. Cryopreservation did not significantly modify the hormone response to glucose but it partially reversed the TNF alpha-induced inhibitory effect on insulin release in the presence of 20 mM glucose. In addition, the inhibitory effect of TNF alpha on phosphatidylcholine labeling was attenuated in cryopreserved islets compared with noncryopreserved islets. TNF alpha significantly stimulated islet nitrite production and cGMP accumulation, both effects being of a similar magnitude in cryopreserved and noncryopreserved islets. Our results suggest that cryopreservation can modify the metabolic and hormone response of human islets to TNF alpha. This effect is not mediated by changes in the TNF alpha-induced islet nitric oxide production or cGMP accumulation.

Adolescent↗
PubMed1996

Dermatofibrosarcoma protuberans.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a locally aggressive soft tissue sarcoma in which recurrences are common. It usually affects middle-aged individuals with the most common location being the trunk. Sex distribution varies among published series. Mohs surgery is the treatment of choice. Immunostaining for CD34 facilitates the diagnosis of DFSP and aids in indicating the surgical margins of the tumor; however, the sensitivity of this marker is variable. MATERIALS AND METHODS: This is a retrospective review of 16 cases of DFSP treated with Mohs surgery at Duke University Medical Center between 1981 and 1994. Clinical and histologic features are analyzed. Immunohistochemical stains for CD34 were performed in one case. RESULTS: Twelve of the 16 patients were women with four younger than 20 years. The most common location was the trunk. No recurrences following Mohs surgery have been documented. The average number of stages during Mohs surgery was 3.3. Surgical wounds were repaired by complex layered closure in 11 cases. Stains for CD34 were negative on the initial biopsy, but were positive on frozen sections. CONCLUSIONS: Both sexes and all age groups are affected by DFSP. Mohs surgery is the treatment of choice and offers a significant improvement in cure rates with the cosmetic advantage of smaller postoperative wounds. Immunostains for CD34 appear to be an important adjunct to facilitate tumor removal, but the variable expression of CD34 antigen by DFSP tumors can lead to variable staining patterns.

Adolescent↗
PubMed1996

PEL, a 'new' high-frequency red cell surface antigen.

A 'new', inherited, high-frequency blood group antigen has been named PEL and is numbered 901014. Two PEL-propositi with anti-PEL have been found, both French-Canadians. Two other French-Canadian propositi with very weak expression of PEL on their red cells have an antibody, provisionally named anti-MTP, which does not react with PEL-cells.

Adult↗
PubMed1996

Dermatofibrosarcoma protuberans treated with Mohs surgery. A case with CD34 immunostaining variability.

BACKGROUND: Immunohistochemical stains for CD34 antigen can help in differentiating dermatofibrosarcoma protuberans (DFSP) from other fibrohistiocytic tumors and in demarcating its surgical margins during Mohs surgery. However, variable expression of CD34 antigen in nodular areas can sometimes result in negative staining of tissue sections creating diagnostic and therapeutic dilemmas. OBJECTIVE: To show the variable expression of CD34 antigen in a DFSP tumor. METHODS: Case presentation of DFSP with immunohistochemical staining using the ABC peroxidase macromolecular complex. RESULTS: Microscopic examination of paraffin-embedded sections showed CD34-negative DFSP tumor cells with positive staining of endothelial cells. On frozen sections at the time of surgery the tumor cells stained strongly positive for CD34. CONCLUSION: This case demonstrates the variable expression of CD34 antigen by DFSP tumors and emphasizes the need to interpret with caution the results of these immunostains during Mohs surgery.

Adult↗
PubMed1996

Pancreatic sarcoidosis.

Sarcoidosis affects every organ in the body; the most frequently involved structures are the lung, lymph nodes, liver, spleen, eyes, joints and heart. Gastrointestinal system affliction is uncommon. The pancreas is rarely affected by sarcoidosis. A review of the literature revealed only 13 patients with biopsy proven granulomas in pancreas or peripancreatic nodes. In a review of all autopsies performed between 1950 and 1993 at Los Angeles County + University of Southern California School of Medicine, Los Angeles, USA, the authors found one patient with pancreatic and 5 with peripancreatic lymph node granuloma. The authors also describe three previously unreported cases of pancreatic sarcoidosis. From the discussion, a clinically useful and pragmatic profile of pancreatic sarcoidosis emerges. Two thirds of the patients with pancreatic sarcoidosis have abdominal pain, and three quarters of them have bilateral hilar adenopathy. The occurrence of abdominal pain in a woman with bilateral hilar adenopathy with or without pulmonary infiltration should lead one to think of pancreatic sarcoidosis. The diagnosis should be established by a tissue biopsy because the laboratory and radiographic techniques do not differentiate pancreatic sarcoidosis from other inflammatory and malignant disorders of the pancreas. The prognosis of pancreatic sarcoidosis is good.

Adult↗
PubMed1995

Solution structure of the ribosome-binding domain of E. coli translation initiation factor IF3. Homology with the U1A protein of the eukaryotic spliceosome.

Initiation of translation in prokaryotes requires the formation of a complex between the messenger RNA, the 30 S ribosomal subunit and the initiator tRNA(fMet). Initiation factor IF3 binds to the 30 S ribosomal subunit and proof-reads the initiation complex, thereby ensuring the accuracy of this step. IF3 also plays a pleiotropic role in the regulation of translation, as a result of differential influences exerted on the levels of the initiation of translation of genes or groups of genes. IF3 is composed of two independent domain or roughly identical sizes. We have expressed and purified the C-terminal domain of E. coli IF3 and shown that it retains both the 30 S particle binding and 70 S ribosome dissociating activities of the native protein. We have obtained 1H and 15N NMR resonance assignments and its 3D solution structure was calculated using 551 restraints. It is composed of a mixed beta-sheet backed by two alpha-helices. It shows a striking resemblance to the U1A small nuclear ribonucleoprotein structure, which binds to the U1 snRNA in the eukaryotic spliceosome. This suggests a convergent evolution process for these two proteins that are associated with ribonucleoproteic complexes.

Amino Acid Sequence↗
PubMed1995

1H and 15N resonance assignments and structure of the N-terminal domain of Escherichia coli initiation factor 3.

Initiation factor IF3 from Escherichia coli is composed of two domains connected by a hydrophilic peptide. In this study, the N-terminal domain (residues 7-83) has been overexpressed, 15N labelled and purified. NMR assignments for this domain have been obtained by two-dimensional and three-dimensional heteronuclear and homonuclear spectroscopy. Using distance geometry and simulated annealing, a three-dimensional solution structure was calculated using 506 NOE and 56 dihedral angle restraints. The resulting structure is composed of a five-stranded antiparallel beta sheet surrounded by two alpha helices. Since the heteronuclear 1H-15N correlation spectrum of the N-terminal domain of IF3 is an almost exact subset of that of the native protein, the assignments obtained and the structure calculated should be directly transposable to the full-length protein.

Amino Acid Sequence↗
PubMed1995

Hypermutation generating the sheep immunoglobulin repertoire is an antigen-independent process.

Somatic hypermutation of light chain V genes during development of B cells in sheep ileal Peyer's patches was studied in three experimental conditions: in sterile fragments of the ileum surgically isolated from the gut during fetal life, in germ-free sheep, and in animals thymectomized during early fetal life. The somatic mutation pattern was found identical to control tissues in all three experiments. The same age-dependent amount of mutations, a higher than theoretical R/S ratio in complementarity-determining regions (CDRs), and a similar clustering of mutations in CDRs were observed. The mechanism, as estimated from the silent mutation pattern, appears to target mutations to CDRs; moreover, the major V lambda genes have a specific codon usage with a high purine content at the first two bases of the codons and a low content at the third position, which, together with a specific targeting of mutations to purines, favors replacement mutations in CDRs.

Animals↗
PubMed1995

Silicone breast implant--associated musculoskeletal manifestations.

Three hundred consecutive women with silicone breast implants (SBI), referred to the arthritis clinic with a variety of musculoskeletal complaints, were evaluated for the presence of underlying connective tissue disease. A complete history and physical examination were performed, as well as laboratory testing for C-reactive protein, rheumatoid factor; and autoantibody determination by indirect immunofluorescence and immunodiffusion. The group mean age was 44.4 years (range 25-69), the mean time from initial implant surgery to appearance of symptoms was 6.8 years (range: 6m-19y) and 83.3% of women studied had clinical manifestations highly suggestive of an underlying connective tissue disorder. Fifty-four percent met criteria for fibromyalgia and/or chronic fatigue syndrome, distinct connective tissue diseases was detected in 11%, undifferentiated connective tissue disease or human adjuvant disease was found in 10.6%, and a variety of disorders such as angioneurotic oedema, frozen shoulder, multiple sclerosis-like syndrome were present. Several other miscellaneous conditions including recurrent unexplained low grade fever, hair loss, skin rash, sicca symptoms, Raynaud's phenomenon, carpal tunnel syndrome, memory loss, headaches, chest pain, and shortness of breath were also seen accompanying specific and non-specific conditions. Seventy percent of patients who underwent explanation of the implants reported improvement of their systemic symptomatology. A significant proportion of SBI patients referred for rheumatic evaluation have clinical manifestations highly suggestive of an underlying connective tissue disease. Furthermore, improvement of their symptomatology follows explanation of the implants in over half of the patients.

Adult↗
PubMed1995

Influence of hyperthermia on cochlear micromechanical properties in humans.

We investigated the effect of body temperature on transient evoked otoacoustic emissions (TEOAEs) in humans. Hyperthermic conditions were obtained in adults in a climatic chamber. During hyperthermia up to an average temperature of 38.4 degrees C, significant falls were found in total amplitude and peak values of TEOAEs: by 1.3 dB SPL/degree C and 2.3 dB/degree C, respectively. This inhibition affected all spectrum components equally. These findings indicate that the outer hair cell micromechanical activity that is presumed to be measured by TEOAEs is not independent of variations in body temperature. The reduction found in hyperthermia suggests that temperature-dependent mechanisms are involved in the generation of TEOAEs.

Adult↗
PubMed1995

Description of an in vitro platelet function analyzer--PFA-100.

A new in vitro system for the detection of platelet dysfunction, PFA-100, has been developed. It provides a quantitative measure of platelet function in anticoagulated whole blood. The system comprises a microprocessor-controlled instrument and a disposable test cartridge containing a biologically active membrane. The instrument aspirates a blood sample under constant vacuum from the sample reservoir through a capillary and a microscopic aperture cut into the membrane. The membrane is coated with collagen and epinephrine or adenosine 5'-diphosphate. The presence of these biochemical stimuli, and the high shear rates generated under the standardized flow conditions, result in platelet attachment, activation, and aggregation, slowly building a stable platelet plug at the aperture. The time required to obtain full occlusion of the aperture is reported as the "closure time." We have found that impairment of von Willebrand factor, or inhibition of platelet receptors glycoprotein Ib or IIb/IIIa with monoclonal antibodies or peptides, resulted in abnormal closure times. An antifibrinogen antibody, in contrast, failed to show any effect. The test appears to be sensitive to platelet adherence and aggregation abnormalities. The PFA-100 system has potential applications in routine evaluation of platelet function in the clinical setting because of its accuracy, ease of operation, and rapid turnaround of results.

Bleeding Time↗