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Biomedical subjects

J A Ramirez

Publications and source records attributed to J A Ramirez.

At least 55 records · Page 3Linked to original sources
PubMed1997

Eight years experience using the inferior epigastric artery for myocardial revascularization.

We present the initial experience with the use of inferior epigastric artery as a free graft for myocardial revascularization in a series of 41 patients operated on between 1987 and 1989 to show the clinical and angiographic results. Of the 41 patients, 29 were male, 12 female, with ages ranging from 33 to 72 years, and weights from 50 to 86 kg. The inferior epigastric artery grafts were predominantly employed to the anterior interventricular branch and diagonal branch. The proximal anastomosis into the aorta was done directly or with a patch of vein or pericardium. The 32 patients who survived had mean follow-up of 82 months and 22 are in functional class I, 8 in class II and 2 in class III of angina. The early patency rate was: inferior epigastric artery-anterior interventricular branch, 85.7% and inferior epigastric artery-diagonal branch. 85.7%. Sixteen patients underwent angiographic study at a mean follow-up of 81.2 months and the patency rate to the anterior interventricular branch was 77.7% and to the diagonal branch was 100%. Three patients with early occluded inferior epigastric artery were reoperated on 3, 3 and 11 months after the operation. A filiform lumen of the graft and a small ostium in the aorta was found and explained the imperfection of the direct anastomosis due to unbalance thickness of the graft and the aortic wall. Therefore it is occluded that the inferior epigastric artery is an alternative arterial graft for myocardial revascularization and that the use of a vein or pericardium patch can help the proximal anastomosis and improve potency of the graft.

Adult↗
PubMed1997

Anatomy of the cranioencephalic structures of the goat (Capra hircus L.) by imaging techniques: a computerized tomographic study.

A topographic study of the cranioencephalic structure was carried out by computerized tomography on Canarian breed adult goats of medium size and weight, with similar cephalic parameters. In this way, transversal, sagittal and horizontal tomographic images were obtained. Identification of the observed anatomic structures represents the basis of this work from which applicable specie data are derived.

Animals↗
PubMed1997

Use of heteroduplex analysis to classify legionellae on the basis of 5S rRNA gene sequences.

Seventeen different species of Legionella, 12 serogroups of Legionella pneumophila, and 2 Legionella-like amoebal pathogens (LLAP1 and Sarcobium lyticum) were examined by heteroduplex analysis of PCR products of the 5S rRNA gene. Eight different banding patterns were identified, indicating that heteroduplex analysis of this gene can be used to classify these bacteria according to base substitutions between species. This classification may have future applications in clinical and epidemiological studies.

Bacterial Typing Techniques↗
PubMed1997

Tuberculosis in Kentucky: current recommendations for empiric therapy.

Current guidelines for empiric therapy for pulmonary tuberculosis depend on the presence of INH or INH and rifampin resistance (MDRTB) in the community. The objective of this study was to determine the susceptibility of MTB in Kentucky and to consider which therapeutic modality for empiric therapy should be followed. The total number and rate of pulmonary tuberculosis was analyzed and compared to national trends. Data of susceptibility were analyzed based on INH and rifampin resistance. There were 4753 cases of TB in Kentucky between 1984 and 1994. Data of susceptibility were available from 1989 through 1994. Total number of MTB decreased by 14% in 1994 from 1993 but resistance to INH doubled from 3.2% to 7.6%. MDRTB increased from 1.2% to 3.2%. INH resistance > 4% on initial isolates was recorded in Allen, Bell, Estill, Fleming, Jefferson, Kenton, Knott, Oldham, Rowan, and Wolfe counties. Outbreak of MDRTB was documented in Estill County. There was no HIV infection documented in this group. In the rest of the state, INH resistance was < 4%. In counties with INH resistance < 4%, empiric therapy for TB should include 3 drugs: INH and rifampin for 6 months and PZA added for the first 2 months. In counties with INH resistance > 4%, empiric therapy should include 4 drugs: INH, rifampin, PZA, ethambutol or streptomycin. In Estill County with documented MDRTB, empiric therapy should include 5 to 6 drugs: INH, rifampin, PZA, ethambutol, streptomycin, and amikacin. If INH and rifampin resistance is present, the therapy should include at least 3 drugs to which the organism is sensitive. This regimen should be continued until sputum cultures become negative. Further therapy should be continued with 2 drugs for 1 year. HIV infected patients constitute a separate category and therapy for them should be individualized.

Antineoplastic Agents↗
PubMed1996

Isolation of Chlamydia pneumoniae from the coronary artery of a patient with coronary atherosclerosis. The Chlamydia pneumoniae/Atherosclerosis Study Group.

BACKGROUND: Atherosclerosis is pathologically similar to a chronic inflammatory response. Recent reports have suggested that Chlamydia pneumoniae may play a role in the pathogenesis of atherosclerosis. OBJECTIVE: To determine, by using various detection methods, whether C. pneumoniae is present in the coronary arteries of patients with coronary atherosclerosis. DESIGN: Multicenter investigation. SETTING: The Jewish Hospital Heart and Lung Institute in Louisville, Kentucky, and several laboratories. PATIENTS: 12 patients seeking heart transplantation. MEASUREMENTS: Culture for C. pneumoniae was done in HEp-2 cell monolayers. Other methods of detection included polymerase chain reaction (PCR) assay, immunocytochemistry, transmission electron microscopy, and in situ hybridization. RESULTS: Chlamydia pneumoniae was cultured from atherosclerotic plaques in one patient with severe coronary artery disease. The organism was found in the atheromas of this patient by PCR assay, immunocytochemistry, electron microscopy, and in situ hybridization. In addition, at least one testing method showed C. pneumoniae in coronary artery tissue in six of nine additional patients with coronary atherosclerosis. CONCLUSIONS: This study provides direct evidence of the presence of viable C. pneumoniae in atheromatous lesions. A chronic inflammatory response caused by a persistent infection of the coronary arteries may explain the link between C. pneumoniae and atherosclerosis.

Chlamydia Infections↗
PubMed1996

c-MYC oncoprotein production in experimental vein graft intimal hyperplasia.

PURPOSE: The expression of c-MYC oncoprotein in proliferating smooth muscle cells (SMCs) was analyzed in an experimental model of vein graft intimal thickening. METHODS: Superficial epigastric vein grafts were inserted into the femoral arteries of male Sprague-Dawley rats. The vein grafts were harvested at 6 hr, 2 days, 1 week, 2 weeks, and 4 weeks after grafting and were rapidly frozen in liquid nitrogen. Immunohistochemical labeling and morphologic analysis of vein graft sections with a double staining technique were used to identify c-MYC/alpha SMC actin and proliferating cell nuclear antigen (PC10)/alpha SMC actin within intimal cells. c-MYC/alpha SMC actin and PC10/alpha SMC actin positive cells were quantitated in the perianastomotic area (R-1) and the body of the graft (R-2) for each time period. Total wall and intimal thickness of perfusion fixed vein grafts were measured with a computer digitized system. RESULTS: Intimal and total wall thickening in the R-1 region peaked at 1 week (27.4 and 579.4 microns respectively) and were significantly thicker (P < 0.01) than the same region at 6 hr after graft implantation (6.0 and 113.5 microns respectively). Staining for c-MYC and PC10 in R-1 was also significantly higher (P < 0.05) at 1 week (5.75 and 7.00 positive cells/10 cells, respectively) compared with that at 6 hr (1.5 and 1.33, respectively). The R-1 region stabilized and remodeled over the following 3 weeks, while c-MYC and PC10 staining progressively decreased. In the R-2 region, intimal thickness significantly increased (P < 0.05) from 6 hr (4.0 micrometers) to 1 week (12.0 micrometers) and stabilized, while total wall thickness increased throughout the first week and the difference became significant at 2 weeks (P < 0.05). Staining for c-MYC and PC10 paralleled the staining in R-1 with a significant peak at 1 week (P < 0.05). CONCLUSIONS: c-MYC oncoprotein is expressed early after experimental vein grafting, with peak expression at 1 week. This occurs during a period of maximal intimal thickening, SMC proliferation, and increased expression of PC10. Expression of c-myc protooncogene may contribute to the induction and regulation of SMC proliferation, producing intimal hyperplasia.

Actins↗
PubMed1996

Soluble HLA class I antigens in pediatric patients with renal transplants from related living donors without acute rejection and treated with triple therapy.

All HLA class I Ag-expressing cells may be the source of serum Ag sHLA I. T and B lymphocytes secrete considerable amounts of Ag sHLA I in a variety of in vitro and in vivo activation systems. The purpose of this study was to evaluate the level of Ag sHLA I in serum of children with kidney transplants from related living donors without acute rejection and with triple therapy. We studied 25 patients (2-21 years) with first kidney transplant, 19 individuals (10-20 years) undergoing hemodialysis without transplant, and 25 normal children (4-21 years). The levels of Ag sHLA in transplant patients was 0.2-3.2 micrograms/ml (mean = 1.04). The hemodialyzed patients was 0.48-4.5 micrograms/ml (mean = 2.09), and the normal control was 0.30-4.38 micrograms/ml (mean = 2.04). A statistically significant reduction was observed in transplant patients compared to normal control and hemodialyzed patients (p < 0.05 in both cases), whereas between normal and hemodialyzed patients no significant difference was seen (p > 0.05). The reduced levels of Ag sHLA I in blood could be an expression of adequate immunosuppressive treatment.

Adolescent↗
PubMed1996

Diagnosis of Legionella pneumophila, Mycoplasma pneumoniae, or Chlamydia pneumoniae lower respiratory infection using the polymerase chain reaction on a single throat swab specimen.

Diagnosis of Mycoplasma pneumoniae and Chlamydia pneumoniae lower respiratory infections using DNA amplification by polymerase chain reaction (PCR) on throat swab specimens has been reported. In this study we determined the sensitivity of the detection of Legionella pneumophila in simulated throat swab specimens by PCR. Next, we compared the sensitivity and specificity of a single throat swab PCR with the current tests for diagnosis of Legionella spp., M. pneumoniae, and C. pneumoniae in patients with lower respiratory tract infections. Patients' work-up included: (a) throat swab specimen for Legionella spp., M. pneumoniae, and C. pneumoniae PCR; (b) throat swab specimen for C. pneumoniae culture; (c) sputum specimen for L. pneumophila direct fluorescent antibody and culture; (d) urine specimen for L. pneumophila serogroup 1 antigen detection; and (e) serum specimen for L. pneumophila, M. pneumoniae, and C. pneumoniae acute and convalescent antibody titers. A total of 155 patients with lower respiratory infection were enrolled in this prospective study. Throat swab PCR was positive for Legionella spp. in five of the six patients with legionellosis, indicating the presence of this organism in the oropharynx of patients with Legionnaires disease. Mycoplasma pneumoniae PCR was positive in eight of the nine patients with mycoplasma infection. Chlamydia pneumoniae PCR was positive in the two patients with C. pneumoniae infection. None of the other 138 patients with negative PCR had other positive confirmatory tests for respiratory infection by these three organisms (100% specificity). PCR was able to detect 15 of the 17 infected (88.2%). Results of this investigation indicate that PCR on a single throat swab specimen is a rapid, sensitive, and specific test that may greatly simplify the diagnosis of lower respiratory infection caused by Legionella spp., Mycoplasma pneumoniae, or C. pneumoniae.

Adolescent↗
PubMed1996

Immunolocalization and temporal distribution of cytokine expression during the development of vein graft intimal hyperplasia in an experimental model.

PURPOSE: Vein graft stenosis caused by intimal hyperplasia (IH) accounts for 30% to 50% of late bypass graft failures; however, the biochemical mediators of vein graft IH have been poorly defined. We attempted to evaluate the spatial and temporal distribution of five principal cytokines (interleukin-1 beta [IL-1 beta], platelet-derived growth factor-AA [PDGF-AA], basic fibroblast growth factor [bFGF], interferon gamma [INF gamma], and tumor necrosis factor alpha [TNF-alpha]) during the development of IH in a rat vein graft model. METHODS: Rat epigastric vein interposition grafts in the femoral artery were harvested at 6 hours, 2 days, 1 week, 2 weeks, and 4 weeks after the grafting procedure and studied with immunohistochemical and standard histologic techniques. The cytokine expression in the endothelium and media/neointima was quantified as the percentage of immunopositive cells per high-power field. RESULTS: Maximal hyperplasia occurred 2 weeks after the grafting procedure. Peak expression of IL-1 beta and bFGF occurred by 2 days. PDGF-AA expression paralleled the development of IH, peaking at 2 weeks and then declining. TNF-alpha expression increased at 1 week and remained elevated. INF gamma was seen only in control grafts. CONCLUSIONS: The coordinated early release of IL-1 beta and bFGF and the down-regulation of INF gamma seem to trigger an inflammatory response, thereby initiating IH. The process then is propagated by the release of PDGF-AA and TNF-alpha, with concomitant smooth muscle cell proliferation and production of extracellular matrix. It is likely that this complex milieu of local paracrine signaling is required to generate the hyperplastic response seen in failing vein grafts.

Actins↗
PubMed1996

Replication of Chlamydia pneumoniae in vitro in human macrophages, endothelial cells, and aortic artery smooth muscle cells.

Chlamydia pneumoniae has recently been associated with atherosclerotic lesions in coronary arteries. To investigate the biological basis for the dissemination and proliferation of this organism in such lesions, the in vitro growth of C. pneumoniae was studied in two macrophage cell lines, peripheral blood monocyte-derived macrophages, human bronchoalveolar lavage macrophages, several endothelial cell lines, and aortic smooth muscle cells. Five strains of C. pneumoniae were capable of three passages in human U937 macrophages and in murine RAW 246.7 macrophages. Titers were suppressed in both macrophage types with each passage, as compared with growth titers in HEp-2 cells. Both human bronchoalveolar lavage macrophages and peripheral blood monocyte-derived macrophages were able to inhibit C. pneumoniae after 96 h of growth. Eleven C. pneumoniae strains were capable of replicating in normal human aortic artery-derived endothelial cells, umbilical vein-derived endothelial cells, and pulmonary artery endothelial cells. Infection in human aortic artery smooth muscle cells was also established for 13 strains of C. pneumoniae. The in vitro ability of C. pneumoniae to maintain infections in macrophages, endothelial cells, and aortic smooth muscle cells may provide support for the hypothesis that C. pneumoniae can infect such cells and, when infection is followed by an immune response, may contribute to atheroma formation in vivo. More studies are needed to investigate the complex relationship between lytic infection and persistence and the potential for C. pneumoniae to influence the generation of atheromatous lesions.

Cell Line↗
PubMed1996

Antibiotic streamlining: development and justification of an antibiotic streamlining program.

Several techniques can be applied to streamline or optimize antimicrobial therapy in the hospitalized patient. As soon as there is a documented clinical response to intravenous therapy, the antibiotic can be switched to the oral route of administration. This antimicrobial streamlining technique is called switch therapy. This article presents the development of the switch therapy concept, the good clinical outcome obtained with switch therapy in patients with community and nosocomial pneumonia, as well as the cost-savings to our institution after the implementation of this program.

Administration, Oral↗
PubMed1995

Early switch from intravenous to oral cephalosporins in the treatment of hospitalized patients with community-acquired pneumonia.

BACKGROUND: Switch therapy is defined as the early transition from intravenous to oral antibiotics during treatment of infection. This study was designed to evaluate the clinical outcome and length of stay of hospitalized patients with community-acquired pneumonia treated with an early switch from intravenous to oral third-generation cephalosporins. METHODS: Patients with a new roentgenographic pulmonary infiltrate and at least two symptoms (cough, fever, or leukocytosis) were enrolled in this study and treated with intravenous ceftizoxime sodium (1 g every 12 hours) or ceftriaxone sodium (1 g every 24 hours). Patients were switched to oral cefixime (400 mg every 24 hours) as soon as they met the following criteria: (1) resolution of fever; (2) improvement of cough and respiratory distress; (3) improvement of leukocytosis; and (4) presence of normal gastrointestinal tract absorption. RESULTS: Of the 120 patients enrolled, 75 (62%) had clinical data evaluated. Long-term follow-up showed that 74 patients (99%) were cured; one patient required readmission for further intravenous therapy. Mean duration of hospital stay was 4 days. CONCLUSIONS: This investigation demonstrated that an early switch to oral cefixime may be reasonable in hospitalized patients with community-acquired pneumonia who have already shown a good clinical and laboratory response to therapy with intravenous third-generation cephalosporins. This approach is clinically effective and minimizes hospital stay.

Administration, Oral↗
PubMed1995

Metal complexes of the carbonic anhydrase inhibitor methazolamide (Hmacm). Crystal structure of the Zn(macm)2(NH3)2. Anticonvulsant properties of the Cu(macm)2(NH3)3(H2O).

Complexes of Co(II), Cu(II), and Zn(II) with deprotonated methazolamide and ammonia are synthesized and characterized. The complex Zn(macm)2(NH3)2 crystallizes in the monoclinic C2/c space group with a = 13.468(1), b = 6.759(1), c = 23.014(2) A, beta = 90.27(1), and Z = 4. The structure was refined to R = 0.049 (Rw = 0.053). The Zn(II) ion is coordinated to two deprotonated sulfonamido nitrogen atoms of the macm- ligand and two nitrogen atoms of the ammonia ligands in a distorted tetrahedron. The Zn(macm)2(NH3)2 complex is shown to be a simple model for the methazolamide inhibition of CA. EHMO calculations applied to fractional coordinates of the Zn(macm)2(NH3)2 complex indicate that the atomic orbitals of the Zn do not contribute to HOMO and LUMO of the complex. The characteristics of the Cu(macm)2(NH3)3(H2O) as an anticonvulsant agent are tested.

Animals↗
PubMed1995

Calcium-regulated parathyroid hormone secretion in adynamic renal osteodystrophy.

Hypercalcemia and low serum parathyroid hormone (PTH) levels are features of the adynamic lesion (AD) of renal osteodystrophy, but there is little information about parathyroid gland function in this disorder. Therefore, the four parameter model was used to evaluate calcium-regulated PTH release in patients with either adynamic bone or secondary hyperparathyroidism (OF) as documented by bone biopsy and in normal volunteers (NL). Patients had undergone CCPD for 20 +/- 4.2 months, and all received calcium carbonate as the sole phosphate-binding agent. During two hours infusions of sodium citrate, the rate of decline in serum ionized calcium levels did not differ among groups; serum PTH levels rose from 136 +/- 38 to 342 +/- 140 pg/ml in AD and from 691 +/- 99 to 869 +/- 121 pg/ml in OF. Maximum PTH levels were 322 +/- 42% of baseline values in AD but only 146 +/- 9.7% of baseline in OF (P < 0.001), and the increase above baseline levels in AD did not differ from that in NL (300 +/- 25%, NS). During calcium infusions, serum PTH levels fell from 164 +/- 75 to 39 +/- 11 pg/ml in AD and from 622 +/- 76 to 171 +/- 29 pg/ml in OF; minimum serum PTH levels, expressed as a percentage of pre-infusion values, were 25 +/- 2% in AD and 26 +/- 5% in OF (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium↗
PubMed1995

Inhibition of Chlamydia pneumoniae growth in HEp-2 cells pretreated with gamma interferon and tumor necrosis factor alpha.

An in vitro culture system was used to study the effects of increasing concentrations of human cytokines on the intracellular replication of Chlamydia pneumoniae. HEp-2 cell monolayers, pretreated for 24 h with 200 U of human recombinant gamma interferon (IFN-gamma) per ml restricted the intracellular replication of C. pneumoniae. Tumor necrosis factor alpha (TNF-alpha; 25 ng/ml) exhibited a synergistic effect with IFN-gamma by reducing the concentration of IFN-gamma necessary to restrict intracellular growth to 100 U/ml. The addition of 200 micrograms of tryptophan per ml significantly reversed the inhibitory effects of IFN-gamma and TNF-alpha, suggesting involvement of the indoleamine-2,3-dioxygenase pathway in the restriction process.

Chlamydophila pneumoniae↗
PubMed1995

Clinical significance of mycobacterium other than tuberculosis isolated from respiratory specimens at a university hospital.

BACKGROUND: Mycobacteria other than tuberculosis (MOTT) are ubiquitous and have been recognized to cause pulmonary disease. Because of newer laboratory diagnostic techniques, it has become more frequent to identify MOTT from pulmonary specimens. The objective of this study was to determine the spectrum of MOTT in pulmonary specimens in hospitalized patients and determine their clinical significance. METHODS: A retrospective study of all cases of positive pulmonary specimens cultured for MOTT in patients admitted to University of Louisville Hospital from January 1989 to December 1992 was performed. A determination of whether or not the MOTT caused pulmonary disease was made, using the criteria required by the American Thoracic Society. RESULTS: There were 221 positive pulmonary specimen cultures for mycobacteria, of which 164 were MOTT and 57 were M tuberculosis. Of the MOTT isolates, 82 (50%) were M gordonae; 44 (27%) M avium intracellulare; 18 (11%) M chelonae; 12 (7%) M fortuitum; 2 (1%) M kansasii; 2 (1%); M scrofulaceum; 2 (1%) M xenopi; and 2 (1%) M terrae. From all the MOTT cases, only one met the criteria for MOTT pulmonary disease. The rest were found to be non-pathogens, either colonizers or contaminants. CONCLUSION: Newer laboratory diagnostic techniques are improving isolation and identification of MOTT. Even though reports of positive pulmonary specimens for MOTT are becoming more numerous, MOTT was found to be a rare pulmonary pathogen in our hospital, when strict criteria were used.

Hospitals, University↗