Biomedical subjects

S Horowitz

Publications and source records attributed to S Horowitz.

At least 73 records · Page 4Linked to original sources

PubMed1996

Intraamniotic infection in patients with preterm labor and twin pregnancies.

BACKGROUND: Microbial invasion of the amniotic cavity plays a major role in the pathogenesis of preterm labor and delivery in singleton pregnancy. Nevertheless, this association is not well established among patients with multiple gestations. The purpose of our study was to explore the role of intraamniotic infection in the setting of twin pregnancies. METHODS: Consecutive women with twin gestations, intact membranes and preterm labor who underwent transabdominal amniocentesis under sonographic guidance. Amniotic fluid (AF) was retrieved from both sacs and cultured for aerobic and anaerobic microorganisms as well as for Mycoplasma species. Intraamniotic infection was defined as a positive AF culture for microorganisms. Mann Whitney U test or Student t-test or Fisher's exact test were utilized for analysis. RESULTS: Amniotic fluid was obtained from 74 patients. Sixty-eight women delivered prematurely (91.9%). Amniotic fluid culture results were positive for microorganisms in nine cases and all women with intraamniotic infection delivered prematurely as well as 59 (90.7%) patients with negative culture. Among the nine patients with intraamniotic infection, microorganisms were isolated from the presenting sac in five cases (55.6%), from both sacs in three patients (33.3%) and from the upper sac in the remaining case (11.1%). Patients with a positive AF culture had a more advanced cervical dilatation, a shorter interval amniocentesis-to-delivery and a higher incidence of clinical chorioamnionitis than those with a negative AF culture. CONCLUSIONS: The prevalence of intraamniotic infection and clinical and histological chorioamnionitis in twin pregnancies and preterm labor is similar to singleton pregnancies and preterm labor. Therefore, women with multiple gestations and preterm labor should be managed as singleton pregnancies.

Amniotic Fluid↗

PubMed1996

Retinal vascular endothelial growth factor (VEGF) mRNA expression is altered in relation to neovascularization in oxygen induced retinopathy.

The temporal and spatial expression of vascular endothelial cell growth factor (VEGF) mRNA was studied in normal developing cat retina, and in oxygen induced retinopathy. Unexposed control and oxygen-exposed animals (80 h of 80% oxygen from day 3, n = 16) were studied at 1, 2, 4, and 6 weeks after birth. India ink injected retinal flat mounts were used to study vessel progression, and in situ hybridizations using retinal cross sections were used to assess VEGF mRNA accumulation. In controls, as the retina matured, VEGF mRNA hybridization was evident in the ganglion cell layer in a scattered line of distinct cells prior to the ingrowth of vessels, involved the most cells in regions just peripheral to invading vessels and persisted in a fewer positive cells, widely spaced in the vascularized retinas of control, six week animals. In the inner nuclear layer, hybridization initially appeared diffusely and later became localized to a narrow portion of that layer and persisted there. In animals with oxygen induced retinopathy, a substantial increase in hybridization was observed in both the ganglion cell and inner nuclear layers of the avascular retina anterior to the advancing neovascularization. VEGF hybridization decreased abruptly to background levels in both layers at the point were neovascularization met avascular retina. By six weeks, when the neovascularization reached the ora, there was a return of VEGF mRNA in the inner nuclear layer which was similar to normal control expression. A low level of unchanging expression was also observed in the retinal pigment epithelium in both groups at all ages. These results indicate that VEGF mRNA abundance is regulated during retinal vascularization and is increased in relation to oxygen induced neovascularization, suggesting that VEGF may play an important role in both normal retinal vessel development and in the pathophysiology of retinopathy of prematurity.

Animals↗

PubMed1995

The effects of hyperoxia, mechanical ventilation, and dexamethasone on pulmonary antioxidant enzyme activity in the newborn piglet.

It has been previously shown that prophylactic, intravenous dexamethasone (DEX) and intratracheal recombinant human Cu/Zn superoxide dismutase (SOD) ameliorate lung injury in newborn piglets treated with 48 hr of hyperoxia and mechanical ventilation. DEX has many pharmacologic effects, including the possible induction of antioxidant enzyme systems. To investigate whether the effects of DEX are mediated by an increase in endogenous antioxidant enzyme activity, 5 groups of term newborn piglets were studied: Group 1 piglets were ventilated with room air for 48 hr; Group 2 animals were ventilated with 100% O2 for 48 hr; Group 3 animals were ventilated with room air for 48 hr and received DEX (0.7 mg/kg) every 12 h; Group 4 were ventilated with 100% O2 for 48 hr and also received DEX; Group 5 animals were no ventilated and were sacrificed at time 0. At the conclusion of the studies, bronchoalveolar lavage (BAL) was performed and the lungs were removed and homogenized. Lung tissue and BAL were analyzed for SOD, catalase, GPX activities, and total protein concentration. No significant differences in any of these assays were seen in either lung tissue or BAL in the 5 groups. These observations indicate that 48 hr of hyperoxia, mechanical ventilation, or dexamethasone treatment does not induce activity of SOD, catalase, or glutathione peroxidase (GPX) in the lungs of newborn piglets. Thus postnatal DEX appears to minimize neonatal lung injury by mechanisms that are independent of these enzymes.

Analysis of Variance↗

PubMed1995

Microparticle agglutination versus antibody-capture enzyme immunoassay for diagnosis of community-acquired Mycoplasma pneumoniae pneumonia.

Community-acquired Mycoplasma pneumoniae pneumonia is a common disease which is usually diagnosed by serological methods. The objective of the present study was to understand the diagnostic significance and test characteristics of two different serological tests used to identify current Mycoplasma pneumoniae infection. Three hundred sixty-six patients who suffered from community-acquired pneumonia served as the study population. Six hundred ninety-four (328 paired and 38 unpaired) sera were examined for the presence of antibodies to Mycoplasma pneumoniae with commercial kits based on two serological methods, microparticle agglutination and antibody-capture EIA. Agreement between the two kits was 85.2% when individual sera were compared (kappa = 0.62) and 88.5% when patients were compared (Kappa = 0.69). The positive predictive value and the specificity for the identification of current Mycoplasma pneumoniae infection using a single acute-phase serum were 49.3% and 86.9%, respectively, for the microparticle agglutination method, compared to 91.3% and 97.7% for the antibody-capture EIA method (p < 0.001). The negative predictive value and the sensitivity were 86.3% and 48.1% for the microparticle agglutination, not significantly different from the corresponding values of 86.5% and 61.2% for the antibody-capture EIA. It is concluded that the overall agreement between the two methods tested is good, but not perfect. The methods complement each other in the identification of Mycoplasma pneumoniae as the causative agent in patients with community-acquired pneumonia.

Adolescent↗

PubMed1995

Ureaplasma urealyticum cervical colonization as a marker for pregnancy complications.

OBJECTIVES: To determine the clinical significance of cervical colonization with (Ureaplasma urealyticum (Uu) and its possible relationship to pregnancy outcome. METHODS: Cervical cultures for Uu and serum antibodies to Uu were determined in four groups of pregnant women: (1) 117 women who underwent mid-trimester amniocentesis; (2) 47 women with preterm labor and intact membranes; (3) 34 women with preterm premature rupture of membranes; and (4) a control group of 315 healthy women with normal pregnancies. Statistical methods used were the chi-square and Fisher's exact tests. RESULTS: A significant increase in the cervical colonization rate with Uu was detected in all study groups (62%, 77% and 74%, respectively) when compared with the control group (42%). Women at mid-trimester of pregnancy with a positive cervical culture and high levels of antibodies, had a higher rate of pregnancy complications than those with a negative culture and absence of antibodies (62 vs. 28%, respectively; P = 0.0006). CONCLUSION: Cervical colonization with Uu when associated with elevated titers of antibodies to Uu, may serve as a marker for the identification of a subpopulation of women who are at high risk for the development of pregnancy complications.

Adult↗

PubMed1995

Intra-uterine infection in women with preterm premature rupture of membranes: maternal and neonatal characteristics.

OBJECTIVE: Our purpose was to determine the prevalence of intra-uterine infection in patients with preterm premature rupture of membranes and to evaluate the clinical characteristics of women and neonates according to the presence or absence of intrauterine infection. STUDY DESIGN: Trans-abdominal amniocentesis was performed in 90 consecutive patients admitted with preterm premature rupture of membranes. Maternal clinical parameters evaluated included maternal age, origin, gravidity, parity, habitual abortion, previous perinatal death, previous preterm birth, urinary tract infection, fetal distress, abruptio placentae, gestational diabetes, admission-delivery interval and cesarean rate. Neonatal clinical parameters evaluated were gestational age at delivery, birth weight, Apgar score, neonatal gender, perinatal death and neonatal sepsis. RESULTS: The prevalence of intra-uterine infection was 66.6% (60/90). No differences between patients with intra-uterine infection and those without intra-uterine infection were observed in maternal age, origin, gravidity, parity, habitual abortion, previous perinatal death, fetal distress, abruptio placentae, gestational diabetes, admission-delivery interval, cesarean section, neonate's gender, Apgar score at 5 min and neonatal sepsis. On the other hand, gestational age at delivery, birth weight and Apgar score at 1 min were significantly different between the groups. CONCLUSION: An intra-uterine infection was found in two thirds of women presenting with preterm premature rupture of membranes. Women presenting with preterm premature rupture of membranes and intra-uterine infection had a lower gestational age at delivery and consequently had a lower neonatal birth weight than those without intra-uterine infection.

Amniotic Fluid↗

PubMed1995

Quality with a human face? The Samuels Planetree model hospital unit.

BACKGROUND: Hospitals across the country are seeking to restructure the delivery of care. Planetree, an international consumer health care organization, works with hospitals to cultivate educated health care consumers and to create caring inpatient environments. This article gives an overview of Planetree's philosophy, examines staff and patient satisfaction, and contrasts Planetree with total quality management (TQM)/continuous quality improvement (CQI) as practiced at one hospital. PLANETREE'S PHILOSOPHY: Planetree's model differs from other patient-centered or patient-focused care models because of its emphasis on educating patients and making them active partners in the care process. To help make the hospital environment less forbidding, more homelike, and more conducive to social interaction, Planetree physically redesigns the hospital space. STUDY RESULTS: Planetree hopes to achieve many goals with its restructuring of patient care, two of which are staff and patient satisfaction. Preliminary surveys indicate that nurses and nursing assistants on Planetree are more satisfied than are staff on comparable units. The results of patient surveys, however, are more ambiguous. Planetree patients are no more, or no less, satisfied with their care than patients on comparable units. DISCUSSION: Both Planetree and TQM/CQI have goals of improving the delivery of patient care, and there are times when these approaches work in concert. There are times, however, when the different vantage points of TQM/CQI and Planetree may raise different questions and foster different solutions. Questions are also raised regarding whether Planetree benefits all patients in the same way. Furthermore, since it is not clear if Planetree's vision of humanizing patient care brings the results it hopes for, a long-term multifaceted research program is called for.

Aged↗

PubMed1995

Combined effects of nitric oxide and hyperoxia on surfactant function and pulmonary inflammation.

NO and its derivative ONOO- are potent free radicals that can cause cell damage, especially in the presence of O2. To determine the potential pulmonary toxicities of nitric oxide (NO) and peroxynitrite (ONOO-) in vitro, Survanta (2.5 mg/ml) was exposed to ONOO- (0.3-8 mM) in the presence of two different buffering systems (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid and phosphate buffer) and minimum surface tension (MST) was determined with an oscillating bubble surfactometer. Significant increases in MST were seen only with exposure to 8 mM ONOO-, indicating that in vitro, high concentrations of ONOO- can inhibit natural surfactant function. The in vivo effects of NO and hyperoxia were then studied in four groups of newborn piglets ventilated for 48 h with 21% O2, 100% O2, 21% O2 and 100 ppm NO, or with 90% O2 and 100 ppm NO. Five animals served as an untreated control group. Bronchoalveolar lavage fluid (BAL) obtained at 48 h was subjected to centrifugation and the surfactant pellet was reconstituted to 5 mg phospholipid/ml. Significant increases in MST were seen in surfactant from piglets ventilated with NO and 90% O2, compared with either untreated controls or piglets ventilated with 21% O2 for 48 h (P < 0.05, analysis of variance). Significant increases in neutrophil chemotactic activity (NCA) of BAL were also found in the NO and O2 group (P < 0.05), with significant positive interaction between NO and O2 found (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Na,K-ATPase in the cochlear lateral wall of human temporal bones with endolymphatic hydrops.

Meniere's disease has traditionally been thought to arise from a disruption in longitudinal endolymphatic flow. This view has been brought into question by recent experimental studies that have focused attention on derangements of cochlear fluid and electrolyte homeostatic mechanisms in Meniere's disease, including abnormalities in Na,K-ATPase enzymes found in the cochlear lateral wall. The current study examined the immunohistochemical labeling pattern of the major ion-transporting enzyme of the stria vascularis, Na,K-ATPase, in archival sections of hydropic and nonhydropic human temporal bones for increased density of label that could indicate overproduction of fluid. The results showed good labeling of the stria vascularis in the celloidin sections. The hydropic ears tended to have darker label, but the difference was not statistically significant. The findings are consistent with normal functioning of the stria vascularis in cases of Meniere's disease.

Animals↗

PubMed1995

Cell-specific expression of fibronectin in adult and developing rabbit lung.

Fibronectin (FN), a glycoprotein component of the extracellular matrix, plays a role in tissue morphogenesis and tissue-specific differentiation through its effects on cell adhesion, cell shape, and cytoskeletal organization. Immunohistochemistry has been used to show that during lung development FN deposition changes, yet the cell-specific sites of pulmonary FN synthesis have not been determined. Because cellular FN synthesis is reflected by FN mRNA abundance, we performed in situ hybridizations to identify pulmonary tissue with the capacity to synthesize FN. Both in situ mRNA hybridization and immunohistochemical staining were performed on tissue sections from lungs of adults and late gestation fetal and neonatal rabbits. In adults, FN transcripts and immunostaining were clearly seen in endothelial cells, smooth muscle cells, and chondrocytes. During lung development, FN transcripts were virtually ubiquitous except in airway epithelium. There was a gradual decrease in FN mRNA abundance with advancing fetal age, but low levels of FN mRNA persisted in neonatal and adult lungs. In contrast, parenchymal immunostaining increased throughout fetal development and remained elevated in the newborn. FN immunostaining was lower in adult lung. In all tissues examined, airway epithelial cells contained no FN transcripts above background. However, immunostaining was detected in airway basement membrane zones and on luminal surfaces of some epithelial cells. The lack of FN transcripts in airway epithelial cells suggests that FN synthesis does not normally occur in this cell type and that its associated FN immunostaining is from another source. The colocalization of FN mRNA and protein in pulmonary endothelial cells, smooth muscle cells, and chondrocytes in adults strongly suggests that these cells are sites of FN synthesis.

Animals↗

PubMed1995

Antibodies to Ureaplasma urealyticum in women with intraamniotic infection and adverse pregnancy outcome.

OBJECTIVE: To determine the association between antibody response to Ureaplasma urealyticum and pregnancy outcome in women with ureaplasmal invasion of the amniotic cavity. METHODS: A cross section study was performed in our high risk pregnancy unit. Three groups of pregnant women were identified: 1) 271 women at the midtrimester of pregnancy (16-20 weeks), who underwent transabdominal amniocentesis for genetic indications 2) 161 consecutive women admitted with preterm labor and intact membranes. 3) 118 consecutive patients with preterm premature rupture of membranes. Amniotic fluids were cultured for Ureaplasma urealyticum, Mycoplasma hominis and also for other aerobic and anaerobic bacteria. Serum antibodies to Uu were measured by a specific enzyme-linked-immunosorbent-assay. RESULTS: The prevalence of positive AF cultures with Uu in the 3 study groups was 2.9%, 4.3% and 17.8%, and the prevalence of antibodies to Uu in the AF-colonized patients was 50%, 86% and 57%, respectively. Adverse pregnancy outcome (preterm birth, low birth weight or fetal death) among all AF colonized women, was significantly higher in patients with antibodies to Uu than in those without antibodies; preterm delivery 90% vs. 43%, and low birth weight infants or fetal death 85% vs. 28%, p = 0.006 and 0.001 respectively. CONCLUSION: Women with intraamniotic infection with Uu and elevated levels of antibodies to Uu, had a higher rate of preterm delivery, and low birthweight infants/fetal death than those without antibody to Uu.

Adult↗

PubMed1995

The diagnostic value of amniotic fluid Gram stain examination and limulus amebocyte lysate assay in patients with preterm birth.

The purpose of this study was to determine the value of Gram stain examination and Limulus amebocyte lysate (LAL) test in the detection of intraamniotic infection. Ninety women with preterm labor and intact membranes (n = 55) or preterm premature rupture of membranes (PROM) (n = 35) who delivered prematurely were included in the study. Amniotic fluid was cultured for aerobic and anaerobic bacteria as well as for mycoplasmas. Amniotic fluid analysis included Gram stain examination and limulus amebocyte lysate tests. The prevalence of positive amniotic culture was 32.2% (29/90) and the most common isolate was Ureaplasma urealyticum. Patients with preterm PROM group had a higher rate of infection than those with preterm labor and intact membranes 57.1% (20/35) vs. 16.4% (9/55), respectively (p = 0.0001). We found a lower gestational age at delivery and lower mean birth weight in neonates born to mothers with a positive amniotic fluid culture than those with negative amniotic fluid culture. The combined use of Gram stain examination and LAL test had a sensitivity and specificity of 51.7% (15/29) and 95.1% (58/61) respectively for the detection of positive amniotic fluid culture. We conclude that Gram stain examination and LAL test are rapid, simple and specific tests that can be used to detect microbial invasion of the amniotic cavity except in patients with mycoplasmas infections.

Adult↗

PubMed1995

Infection of the amniotic cavity with Ureaplasma urealyticum in the midtrimester of pregnancy.

The purpose of this study was to determine the clinical significance of invasion of the amniotic fluid (AF) with Ureaplasma urealyticum in the midtrimester of pregnancy. Amniotic fluid and cervical swabs obtained from 214 asymptomatic women in the midtrimester of pregnancy (16-20 weeks) were cultured for U urealyticum and Mycoplasma hominis. Inoculum size was determined by quantitative culture. Six of the 214 women (2.8%) had Ureaplasma in high titers in the AF. The pregnancy outcomes of 129 women were determined. Adverse pregnancy outcome occurred more frequently in women with a positive AF culture than in women with a negative AF culture (3/6 [50%] vs. 15/123 [12%], respectively; P = .035). We conclude that infection of the amniotic cavity with U urealyticum can be present in asymptomatic patients in the midtrimester of pregnancy and is a significant risk factor for spontaneous preterm labor and delivery. These observations suggest that routine culture of AF at the time of midtrimester amniocentesis can identify the group of patients at risk for a poor pregnancy outcome.

Abortion, Spontaneous↗

PubMed1994

Independent evolutionary origin of histone H3.3-like variants of animals and Tetrahymena.

All three genes encoding histone H3 proteins were cloned and sequenced from Tetrahymena thermophila. Two of these genes encode a major H3 protein identical to that of T. pyriformis and 87% identical to the major H3 of vertebrates. The third gene encodes hv2, a quantitatively minor replication independent (replacement) variant. The sequence of hv2 is only 85% identical to the animal replacement variant H3.3 and is the most divergent H3 replacement variant described. Phylogenetic analysis of 73 H3 protein sequences suggests that hv2, H3.3, and the plant replacement variant H3.III evolved independently, and that H3.3 is not the ancestral H3 gene, as was previously suggested (Wells, D., Bains, W., and Kedes, L. 1986, J. Mol. Evol., 23: 224-241). These results suggest it is the replication independence and not the particular protein sequence that is important in the function of H3 replacement variants.

Amino Acid Sequence↗

PubMed1994

Mycoplasma genitalium in the joints of two patients with arthritis.

Mycoplasma genitalium was sought in synovial fluids from 13 patients, of whom five had Reiter's syndrome, four had rheumatoid arthritis, and one each had systemic lupus erythematosus, psoriatic arthritis, rheumatic fever and undefined arthritis. The mycoplasma was detected by a PCR assay in the knee joint of a 25-year-old man with Reiter's syndrome, from whom urethral ureaplasmas were isolated and whose synovial fluid mononuclear cells responded to ureaplasmal antigens in a proliferation assay. Mycoplasma genitalium was also detected in the knee joint during an exacerbation of arthritis in a 58-year-old man who had had seronegative juvenile polyarthritis that had evolved to seronegative rheumatoid arthritis.

Adult↗

PubMed1994

A study of chromium induced allergic contact dermatitis with 54 volunteers: implications for environmental risk assessment.

Over the past 60 years, dose-response patch test studies by various methods have been conducted in an attempt to identify the minimum elicitation threshold (MET) concentration of hexavalent chromium (Cr(VI)) that produces an allergic response in Cr(VI) sensitive subjects. These data are not adequate, however, to provide an accurate estimate of the MET because of the variability in the patch testing techniques and the variability in diagnostic criteria used. Furthermore, the data were not reported in terms of mass of allergen per surface area of skin (mg Cr/cm2-skin), which is necessary for conducting occupational or environmental health risk assessments. Thus the purpose of this study was to determine the MET (mg allergen/cm2) for Cr(VI) and trivalent chromium (Cr(III)) by patch testing techniques. A patch test method that delivers a controlled amount of allergen per surface area of skin was used. A group of 54 Cr(VI) sensitised volunteers were patch tested with serial dilutions of Cr(VI) and Cr(III) to determine the cumulative response rate at several concentrations. The results indicate that the 10% MET for Cr(VI) based on the cumulative response was 0.089 micrograms Cr(VI)/cm2-skin. Only one of the 54 volunteers may have responded to 33 micrograms Cr(III)/cm2-skin, otherwise Cr(III) was unable to produce allergic contact dermatitis in these highly sensitive volunteers. Two supplemental studies were also conducted to assess whether the surface area of the patch and the concentration of Cr(VI) in the patch (related to patch thickness) were likely to influence the results. The data from these studies were used to assess the risk of developing allergic contact dermatitis due to contact with Cr(VI) and Cr(III) in soil. The findings indicated that soil concentrations at least as high as 450 ppm Cr(VI) and 165,000 ppm Cr(III) should not pose an allergic contact dermatitis hazard for at least 99.99% of the people in the community who might be exposed.

Adult↗

PubMed1994

Human kidney proximal tubules are the main source of plasma glutathione peroxidase.

The sites of synthesis of extracellular (E) glutathione peroxidase (GPX), a unique selenoglycoprotein present in plasma, are not known. To investigate the possibility that the kidney is the main source for the plasma GPX, we examined GPX activities and selenium concentrations in the plasma of patients with renal failure on dialysis and nephrectomized patients before and after kidney transplantation. Plasma GPX activities in these patients were 42, 22, and 180% of normal EGPX activity, respectively, whereas plasma Se levels were within the normal range. Twenty-four hours after nephrectomy of anesthetized rats, plasma GPX activity was 30.0 +/- 6.4% of the activity at zero time. Northern hybridization analysis of eight human tissues probed with EGPX and cellular glutathione peroxidase (CGPX) cDNA revealed that the ratio of EGPX to CGPX was highest in the kidney. cRNA in situ hybridization studies on kidney slices showed that only proximal tubular epithelial cells and parietal epithelial cells of Bowman's capsule contained EGPX transcripts. Caki-2, a proximal tubular renal carcinoma cell line, makes and actively secretes EGPX. Taken together, these results strongly suggest that kidney proximal tubular cells are the main source for GPX activity in the plasma.

Animals↗

PubMed1994

Human placenta makes extracellular glutathione peroxidase and secretes it into maternal circulation.

Extracellular glutathione peroxidase (eGPX) is a selenoglycoprotein distinct from cellular glutathione peroxidase (cGPX). The cDNA for eGPX has recently been cloned from human placenta. To determine whether human placenta makes both cGPX and eGPX and secretes eGPX, we used specific immunoprecipitations of 75Se metabolically labeled proteins from full-term placental explants in culture and perfused placental lobules. Placental explants and metabolically active, dually perfused placental lobules synthesized and contained both cGPX and eGPX and secreted eGPX. Perfused tissue secreted eGPX into the maternal but not into the fetal perfusate. In situ hybridizations using antisense and sense eGPX riboprobes were performed on sections of first-, second-, and third-trimester placentas. In the first-trimester placenta, transcripts were localized predominantly to cytotrophoblast cells, whereas in the full-term placenta syncytiotrophoblast cells and stromal cells but not fetal endothelial cells expressed eGPX mRNA. It is concluded that human placenta synthesizes both cGPX and eGPX and secretes eGPX into the maternal circulation, consistent with the location of the eGPX mRNA.

Culture Techniques↗