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Biomedical subjects

B Pace

Publications and source records attributed to B Pace.

At least 19 recordsLinked to original sources
PubMed2003

Pleomorphic adenoma of the breast. A case report and distinction from mucinous carcinoma.

Pleomorphic adenoma of the breast is a rare, benign tumor accounting for 68 cases in the literature. It is most commonly seen in postmenopausal women and is characterized by an admixture of epithelial and myoepithelial cells embedded in abundant myxomatous stroma. Its clinical and histologic appearance can be challenging and may lead to a misdiagnosis of invasive carcinoma. We report a case of mammary pleomorphic adenoma in an asymptomatic 59-year-old woman and briefly discuss its distinction from mucinous carcinoma through the use of special stains.

Adenocarcinoma, Mucinous↗
PubMed2000

A technique to retrieve stents dislodged in the coronary artery followed by fixation in the iliac artery by means of balloon angioplasty and peripheral stent deployment.

An unwelcome complication of the increasingly applied technique of coronary stenting is stent dislodgment, which may cause arterial occlusion or distal embolization, both with potentially adverse sequel. Stent dislodgment tends to occur when negotiating a tortuous artery with a balloon-mounted stent, especially if the artery is irregularly calcified or when applying a rigid stent. We have successfully applied in several patients at our laboratory a technique to retrieve a dislodged stent from the coronary artery, tow it to the iliac artery, and then deploy it locally by a peripheral balloon when retrieval through the vascular sheath seems impossible. Finally, the retrieved stent is secured by local anchoring with a peripheral stent. This technique was found to be useful and may prevent further complications and more costly interventions and hence result in a more benign clinical course. Cathet. Cardiovasc. Intervent. 49:77-81, 2000.

Aged↗
PubMed2000

Organochlorine exposures and breast cancer risk in New York City women.

A hospital-based case-control study of breast cancer risk related to organochlorine (OC) exposure was conducted in a multiethnic setting in New York City. We enrolled 175 breast cancer patients and 355 control patients. The overall racial/ethnic distribution was 57% Caucasian, 21% Hispanic, 22% African-American; cases and controls were frequency-matched by age and race/ethnicity. Tumor markers (estrogen and progesterone receptors, p53, erbB-2) were assessed and organochlorines (DDE, DDT, trans-nonachlor, and higher (HPCB) and lower (LPCB) chlorinated biphenyls) were measured in blood serum. Tumors among minority women were of slightly higher stage than among Caucasians, but tumor markers were similar across the racial/ethnic groups. DDE levels were highest among African-American and Hispanic women; DDT was highest among Hispanics; HPCBs were highest among African-Americans; LPCBs were lowest among Hispanics; and trans-nonachlor was highest among African-Americans. However, OC levels were not associated with risk for breast cancer, nor did OCs differ with respect to tumor stage or tumor markers. Higher DDE levels were associated with increasing body mass index (BMI), but with decreasing level of education, frequency of nulliparity, and frequency of family history of breast cancer. HPCB levels decreased with BMI and were not correlated with breast cancer risk factors. These relationships can be attributed to historical patterns of exposure and to metabolic differences in OCs related to BMI.

Black People↗
PubMed1999

Peptide nucleic acid (PNA) binding-mediated induction of human gamma-globin gene expression.

Peptide nucleic acids (PNAs) can bind to homopurine/homopyrimidine sequences of double-stranded DNA targets in a sequence-specific manner and form [PNA]2/DNA triplexes with single-stranded DNA D-loop structures at the PNA binding sites. These D-loop structures have been found to have a capacity to initiate transcription in vitro. If this strategy can be used to induce transcription of endogenous genes, it may provide a novel approach for gene therapy of many human diseases. Human [beta] globin disorders such as sickle cell anemia and beta-thalassemia are very common genetic diseases that are caused by mutations in the beta-globin gene. When gamma-globin genes are highly expressed in sickle cell patients, the presence of high levels of fetal hemoglobin (HbF, alpha2gamma2) can compensate for the defective beta-globin gene product and such patients have much improved symptoms or are free of disease. However, the gamma-globin genes are developmentally regulated and normally expressed at very low levels (>1%) in adult blood cells. We have investigated the possibility of inducing gamma-globin gene expression with PNAs. Using PNAs designed to bind to the 5' flanking region of the gamma-globin gene, induction of expression of a reporter gene construct was demonstrated both in vitro and in vivo. More importantly, PNA-mediated induction of endogenous gamma-globin gene expression was also demonstrated in K562 human erythroleukemia cells. This result suggests that induction of gamma-globin gene expression with PNAs might provide a new approach for the treatment of sickle cell disease. PNA-induced gene expression strategy also may have implications in gene therapy of other diseases such as genetic diseases, cancer and infectious diseases.

Anemia, Sickle Cell↗
PubMed1997

BFU-E colony growth in response to hydroxyurea: correlation between in vitro and in vivo fetal hemoglobin induction.

Patients with sickle-cell anemia treated with hydroxyurea may have significant reduction in frequency and severity of pain episodes. However, previous clinical trials show a variable response to hydroxyurea. Criteria which can be used to select patients who are likely to respond to hydroxyurea treatment would be useful. Our laboratory has previously demonstrated an inverse linear relationship between the total number of burst-forming unit-erythroid (BFU-E) colonies and fetal hemoglobin levels in sickle-cell patients treated with hydroxyurea. In the present report, an in vitro cell culture system was established to evaluate the effects of hydroxyurea on BFU-E colony growth and induction of fetal hemoglobin production. Five Hb SS patients who were not previously treated with hydroxyurea and three Hb SS patients who failed to respond to hydroxyurea treatment were included in the study. The results show that the number of BFU-E colonies is decreased from 153.7 to 7.2 per 3 x 10(5) mononuclear cells, whereas fetal hemoglobin levels were increased from 5.1 to 19.4% in the presence of hydroxyurea in vitro in cultured erythroid progenitors, which were derived from 5 patients before treatment. The number of BFU-E colonies decreased from 153.7 to 2.0 per 3 x 10(5) mononuclear cells in the in vitro cultures obtained from serial peripheral blood samples over a 9- to 20-week period of oral hydroxyurea therapy. A simultaneous rise in fetal hemoglobin level from 10.2 to 28.6% in the peripheral blood over the same period of hydroxyurea therapy was also observed. Our results demonstrate that the increase in fetal hemoglobin levels in cells treated with hydroxyurea in vitro is comparable to the rise of fetal hemoglobin production following hydroxyurea therapy in these patients. On the contrary, these findings were not observed in three previously non-responsive sickle-cell patients. These results suggest that the changes in number of BFU-E colonies and fetal hemoglobin levels after in vitro exposure to hydroxyurea may be a useful approach to select sickle-cell patients who will respond to hydroxyurea therapy.

Adolescent↗
PubMed1994

alpha-Amino butyric acid cannot reactivate the silenced gamma gene of the beta locus YAC transgenic mouse.

Butyric acid, a naturally occurring fatty acid, has been shown to increase fetal hemoglobin in BFUe cultures, in primates, and in patients with beta chain hemoglobinopathies. The precise mechanism of gamma gene induction by butyrate is unknown. Butyrate may induce fetal hemoglobin production in vivo by reactivation of silenced gamma globin genes, by inhibiting the silencing of gamma genes, or by both mechanisms. We examined the effects of butyrate on gamma gene expression in transgenic mice carrying three types of constructs: microLCRA gamma mice, which continue to express the gamma gene in the adult stage of development at a level of one-third to one-fifth of the expression in the fetus; microLCRA gamma psi beta delta beta mice, which display correct developmental regulation of gamma and beta human globin genes and have low level gamma globin expression in the adult; and beta locus YAC mice, which display correct developmental regulation of epsilon, gamma, and beta globin genes and have a totally silenced gamma gene in the adult stage. Animals were treated with a continuous infusion of alpha-amino butyric acid (alpha-ABA) for 7 days. In microLCRA gamma mice alpha-ABA produced up to a 43-fold induction of gamma and 9-fold induction of mouse alpha globin genes. In contrast, butyrate did not induce gamma globin expression in the beta locus YAC mice. However, the gamma globin genes of beta locus YAC mice were activated after administration of 5-azacytidine (5-azaC), and the level of gamma globin expression was further increased by administration of alpha-ABA. These results suggest that butyrate cannot reactivate a totally silenced gamma gene and that induction of fetal hemoglobin by this compound may require the presence of preactivated gamma globin genes.

Aminobutyrates↗
PubMed1994

Fetal hemoglobin induction by acetate, a product of butyrate catabolism.

Butyrate induces fetal hemoglobin (HbF) synthesis in cultures of erythroid progenitors, in primates, and in man. The mechanism by which this compound stimulates gamma-globin synthesis is unknown. In the course of butyrate catabolism, beta oxidation by mitochondrial enzymes results in the formation of two acetate molecules from each molecule of butyrate. Studies were performed to determine whether acetate itself induces HbF synthesis. In erythroid burst-forming unit (BFU-E) cultures from normal persons, and individuals with sickle cell disease and umbilical-cord blood, dose-dependent increases in gamma-globin protein and gamma mRNA were consistently observed in response to increasing acetate concentrations. In BFU-E cultures from normal adults and patients with sickle cell disease, the ratio of gamma/gamma + beta mRNA increased twofold to fivefold in response to acetate, whereas the percentage of BFU-E progeny staining with an anti-gamma monoclonal antibody (MoAb) increased approximately twofold. Acetate-induced increases in gamma-gene expression were also noted in the progeny of umbilical cord blood BFU-E, although the magnitude of change in response to acetate was less because of a higher baseline of gamma-chain production. The effect of acetate on HbF induction in vivo was evaluated using transgenic mouse and primate models. A transgenic mouse bearing a 2.5-kb mu locus control region (mu LCR) cassette linked to a 3.3-kb A gamma gene displayed a near twofold increase in gamma mRNA during a 10-day infusion of sodium acetate at a dose of 1.5 g/kg/d. Sodium acetate administration in baboons, in doses ranging from 1.5 to 6 g/kg/d by continuous intravenous infusion, also resulted in the stimulation of gamma-globin synthesis, with the percentage of HbF-containing reticulocytes (F reticulocytes) approaching 30%. Surprisingly, a dose-response effect of acetate on HbF induction was not observed in the baboons, and HbF induction was not sustained with prolonged acetate administration. These results suggest that both two-carbon fatty acids (acetate) and four-carbon fatty acids (butyrate) stimulate synthesis of HbF in vivo.

Acetates↗
PubMed1992

Evolutionary relationships among sulfur- and iron-oxidizing eubacteria.

Some 37 reverse transcriptase, partial 16S rRNA sequences from sulfur- and/or iron-oxidizing eubacteria, including sequences from species of the genera Thiobacillus, Thiothrix, Thiomicrospira, Acidophilium, "Leptospirillum," Thiovulum, and Chlorobium, have been determined. In addition, 16S sequences from a number of unnamed sulfur- and/or iron-oxidizing bacteria from hydrothermal vent sites, from invertebrate-bacterial endosymbioses, and from various mineral recovery operations also have been determined. The majority of sequences place their bacterial donors in one or another of the subdivisions of the Proteobacteria. However, three unnamed facultatively thermophilic iron-oxidizing isolates, Alv, BC, and TH3, are affiliated with the gram-positive division. One H2S-oxidizer, from the genus Thiovulum, is affiliated with Campylobacter, Wolinella, and other genera in what appears to be a new subdivision of the Proteobacteria. Three "Leptospirillum"-helical vibrioid isolates, BU-1, LfLa, and Z-2, exhibit no clear phylum level affiliation at all, other than their strong relationship to each other. A picture is emerging of an evolutionary widespread capacity for sulfur and/or iron oxidation among the eubacteria.

Bacteria↗
PubMed1991

Pulmonary manifestations of HIV infection in children.

We retrospectively reviewed the spectrum, course, and outcome of pulmonary diseases in 66 children with AIDS, hospitalized between 1982 and 1988, prior to the use of zidovudine. Fifty-two of the 66 (79%) patients developed pulmonary problems. In fifty-two percent of all patients, a pulmonary problem was the first symptom of HIV infection. The most common respiratory illness requiring hospitalization was an episode of respiratory distress with normal PaO2 and unchanged X-ray with a 9.7 +/- 6.8 days mean duration of hospitalization. Bacterial pneumonia, Pneumocystis carinii pneumonia (PCP) and pulmonary lymphoid hyperplasia/lymphoid interstitial pneumonia occurred in 30%, 32% and 22% of the patients, respectively. Bacterial pneumonia and PCP were associated with a high mortality rate. Sixty-eight percent of the patients died within 24 months of the onset of pulmonary disease. In 50% of the children, pulmonary disease was a primary cause of death. The results of this study can be useful in developing prospective studies for the prevention and treatment of pulmonary complications of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Characterization of ribonuclease P from the archaebacterium Sulfolobus solfataricus.

Ribonuclease P is the endonuclease that removes the leader fragments from the 5'-ends of precursor tRNAs. The enzyme isolated from eubacteria contains a catalytic RNA subunit. RNAs also copurify with eukaryotic RNase P, although catalysis by those RNAs has not been demonstrated. This paper reports the isolation and characterization of ribonuclease P from the thermoacidophilic archaebacterium Sulfolobus solfataricus. Archaebacteria are a primary evolutionary lineage, distinct from both eukaryotes and eubacteria. Ribonuclease P of S. solfataricus has reaction component requirements and a Km for substrate tRNA (2.5 X 10(-7) M) that are roughly similar to those reported for eubacterial and eukaryotic ribonuclease P. The temperature optimum for the reaction is 77 degrees C, reflecting the thermophilic character of the organism. The enzyme activity is not affected by treatment with micrococcal nuclease, suggesting that there is no RNA subunit or that it is protected from nuclease action. The density of the enzyme in cesium sulfate equilibrium density gradients is 1.27 g/ml, which is similar to that of protein. However, several RNAs between 200 and 400 nucleotides in size copurify with the enzyme activity on the density gradients, and one of them remains after micrococcal nuclease treatment. These properties of the S. solfataricus enzyme are compared with those of ribonuclease P from eukaryotes and eubacteria.

Archaea↗
PubMed1990

Knowledge of AIDS risk factors in south Bronx minority college students.

Hostos Community College is located in the South Bronx, an epicenter of the AIDS epidemic. The student body is 84% Hispanic and 12% black; Hispanics and blacks account for 70% of AIDS cases among heterosexual adults nationwide and 75% of pediatric cases. We surveyed 1,869 Hostos students to determine their understanding of AIDS risk factors. Respondents' age, English proficiency, time in the college, and time in the United States did not correspond in any consistent way with understanding of risk factors. Sexual intercourse without a condom was recognized as increasing risk by only 69% of all respondents, having a sexual partner who used i.v. drugs 5 years ago by 61%, and having a partner who had a male homosexual relationship 5 years ago by 58%. Only 55% were aware of the risk to the baby if the mother had a partner who used i.v. drugs 5 years earlier. The lack of information observed in college students understates that within the South Bronx as a whole and portends increased heterosexual and pediatric transmission of AIDS. This survey shows that the public health AIDS prevention education program has not yet adequately informed a large segment of the minority population of the South Bronx.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Outcome of mechanical ventilation in children with acquired immunodeficiency syndrome.

We retrospectively reviewed the records of 18 children with acquired immunodeficiency syndrome (AIDS) who required mechanical ventilation for respiratory failure. These patients represented 35% of the patients seen with pulmonary disease and AIDS. The most common causes of respiratory failure were Pnuemocystis carinii pneumonia (77%) and bacterial pneumonia (33%). Bronchial lavage by fiberoptic bronchoscopy or endotracheal tube suctioning in mechanically ventilated children with AIDS had a high yield for P. carinii. Eight of 18 (44%) children survived the episode of respiratory failure and were weaned from the ventilator. However, four of eight survivors died within 6 months. Arterial oxygen tension on admission and maximum peak inspiratory pressure on the ventilator did not differ between survivors and nonsurvivors. We conclude that children with AIDS who are mechanically ventilated can be weaned from the respirator but that the subsequent course remains poor.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Role of the protein moiety of ribonuclease P, a ribonucleoprotein enzyme.

The Bacillus subtilis ribonuclease P consists of a protein and an RNA. At high ionic strength the reaction is protein-independent; the RNA alone is capable of cleaving precursor transfer RNA, but the turnover is slow. Kinetic analyses show that high salt concentrations facilitate substrate binding in the absence of the protein, probably by decreasing the repulsion between the polyanionic enzyme and substrate RNAs, and also slow product release and enzyme turnover. It is proposed that the ribonuclease P protein, which is small and basic, provides a local pool of counter-ions that facilitates substrate binding without interfering with rapid product release.

Bacillus subtilis↗
PubMed1988

The identifier concept: clinical parameters to stratify hospital patient costs within gynecology diagnosis-related groups.

The purpose of this study was to analyze whether clinical variables could stratify hospital costs within gynecology diagnosis-related groups. We analyzed 3171 gynecologic admissions to a large teaching hospital and found that the parameters of nonemergency and intensive care unit admission and blood or plasma product utilization could stratify hospital costs and outcome within a gynecology diagnosis-related group. Patients with the variables had higher total hospital costs, a longer hospital length of stay, more procedures per patient, a greater proportion of outliers, and a higher mortality than patients without the variables. This study demonstrates that these four clinical variables could be used to focus cost-containment efforts on gynecologic patients incurring higher costs in the coming era of limited resources.

Blood Transfusion↗