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Biomedical subjects

R Porat

Publications and source records attributed to R Porat.

At least 19 recordsLinked to original sources
PubMed2005

Effect of pulsed short-wave diathermy on pain and function of subjects with osteoarthritis of the knee: a placebo-controlled double-blind clinical trial.

OBJECTIVE: To examine the effects of pulsed short-wave diathermy (PSWD), delivered at an intensity sufficient to induce a thermal sensation and at an athermal intensity, in comparison with a placebo short-wave diathermy treatment, on reported pain, stiffness and functional ability and on mobility performance of patients with osteoarthritis of the knee. DESIGN: A placebo-controlled double-blind trial with sequential allocation of patients to different treatment groups. SETTING: Outpatient physiotherapy department. SUBJECTS: One hundred and three consecutive patients, mean age 73.7 (+/-6.6) years with osteoarthritis of one or both knees for at least three months. INTERVENTIONS: All participants received three 20-min-long treatments per week for three weeks. One group received PSWD with mean power of 18 W (thermal effect), one group received PSWD with mean power of 1.8 W (athermal effect), and one group received sham short-wave diathermy treatment. Patients were assessed before the initial treatment, immediately following the last treatment, and at a three-month follow-up. MAIN MEASURES: Outcome measures included the WOMAC Osteoarthritis Index, which assessed reported pain, stiffness, and functional ability, and four measures of mobility performance: Timed Get Up and Go test (TGUG), stair-climbing, stair, descending and a 3-min walk. RESULTS: A difference across time was observed for the pain and stiffness categories of the WOMAC Osteoarthritis Index (p = 0.033 and p = 0.008, respectively), with no differences between groups. No other significant differences across time or between groups were observed in any of the other measures. CONCLUSION: The findings do not demonstrate pulsed short-wave diathermy, as it is utilized in clinical settings, to be effective in the treatment of osteoarthritis of the knee.

Activities of Daily Living↗
PubMed2001

Uracil moiety is required for toxicity of the cyanobacterial hepatotoxin cylindrospermopsin.

A new natural derivative of the sulfated guanidinium zwitterionic toxin cylindrospermopsin, 7-epi-cylindrospermopsin, was recently isolated from the cyanobacterium Aphanizomenon ovalisporum (Forti). The toxicity of the molecule (LD50 ip 5 d), estimated by mouse bioassay, was 200 microg/kg mouse, a value similar to that of cylindrospermopsin. Treatment of cylindrospermopsin with chlorine solution or chlorine-related oxidants produced two new derivatives. The chemical structure of these products was elucidated by nuclear magnetic resonance (NMR) and mass spectrometry (MS) techniques and toxicity was determined. In the first derivative, the vinylic proton at position 5 of the pyrimidine ring was substituted by chlorine to yield 5-chlorocylindrospermopsin. The other product is a truncated one, where C-6 of the pyrimidine ring was oxidized to a carboxylic acid. A trivial name, cylindrospermic acid, was given to this compound. Both products showed no toxic effects even at doses 50 times higher than the LD50 of cylindrospermopsin (10 mg/kg mouse ip). Based on these results, the pyrimidine ring is postulated as the molecule component essential for the toxicity of cylindrospermopsin.

Alkaloids↗
PubMed2001

Clinical correlations in infants in the neonatal intensive care unit with varying severity of gastroesophageal reflux.

BACKGROUND: Gastroesophageal reflux (GER) is frequently a benign condition in infancy with spontaneous resolution. In the neonatal intensive care unit (NICU), however, it can add to neonatal morbidity if not adequately diagnosed and treated. The objective of the current study was to analyze factors associated with GER in infants in the NICU and correlate them with the severity of the disease. METHODS: All infants in the NICU (n = 150; born November 1994 through April 1999) who were evaluated by a five-channel pH study to rule out GER were included in the study. Infants were grouped as normal, with a reflux index (RI) of less than 6 (n = 66); mild, with RI of 6 to 14 (n = 42); and severe, with RI of more than 14 (n = 42). Maternal and neonatal data were obtained. Clinical GER was defined as the presence of feeding problems (significant gastric residue or emesis) and medical improvement with antireflux measures and medications. RESULTS: There was no difference in birth weight, gestational age; incidence of patent ductus arteriosus, intraventricular hemorrhage, necrotizing enterocolitis, or chronic lung disease; and treatment with aminophylline or caffeine among the groups. Infants with mild and severe GER (RI 6-14 and >14) had significantly more clinical GER than the normal group (P = 0.0001). Additionally, infants with RI more than 14 had significantly more respiratory distress syndrome, lower hematocrits at the time of study and longer length of stay than those with no or mild GER (P = 0.02). CONCLUSION: Infants with severe GER had lower hematocrits despite receiving more blood transfusions and iron therapy. Infants with severe GER also had prolonged hospital stays. Early diagnosis and aggressive management of GER may decrease neonatal morbidity and result in earlier discharge from the NICU.

Cohort Studies↗
PubMed2001

Gene transfer by viral vectors into blood vessels in a rat model of retinopathy of prematurity.

AIMS: To test the feasibility of gene transfer into hyaloid blood vessels and into preretinal neovascularisation in a rat model of retinopathy of prematurity (ROP), using different viral vectors. METHODS: Newborn rats were exposed to alternating hypoxic and hyperoxic conditions in order to induce ocular neovascularisation (ROP rats). Adenovirus, herpes simplex, vaccinia, and retroviral (MuLV based) vectors, all carrying the beta galactosidase (beta-gal) gene, were injected intravitreally on postnatal day 18 (P18). Two sets of controls were also examined: P18 ROP rats injected with saline and P18 rats that were raised in room air before the viral vectors or saline were injected. Two days after injection, the rats were killed, eyes enucleated, and beta-gal expression was examined by X-gal staining in whole mounts and in histological sections. RESULTS: Intravitreal injection of the adenovirus and vaccinia vectors yielded marked beta-gal expression in hyaloid blood vessels in the rat ROP model. Retinal expression of beta-gal with these vectors was limited almost exclusively to the vicinity of the injection site. Injection of herpes simplex yielded a punctuate pattern of beta-gal expression in the retina but not in blood vessels. No significant beta-gal expression occurred in rat eyes injected with the retroviral vector. CONCLUSIONS: Adenovirus is an efficient vector for gene transfer into blood vessels in an animal model of ROP. This may be a first step towards utilising gene transfer as a tool for modulating ocular neovascularisation for experimental and therapeutic purposes.

Animals↗
PubMed2001

Vascular endothelial growth factor and vascular adjustments to perturbations in oxygen homeostasis.

Development of microvascular networks is set to meet the metabolic requirements of the tissue they perfuse. Accordingly, impairment of oxygen homeostasis, either due to increased oxygen consumption or as a result of blood vessel occlusion, triggers compensatory neovascularization. This feedback reaction is mediated by a hypoxia- and hypoglycemia-induced vascular endothelial growth factor (VEGF). VEGF accumulates under stress as a result of increased hypoxia-inducible factor-1alpha-mediated transcription, stabilization of the mRNA, and the function of a hypoxia-refractory internal ribosome entry site within its 5'-untranslated region. Matching of vascular density to the metabolic needs of the tissue may include a process of hyperoxia-induced vessel regression. Thus newly formed vascular networks may undergo a natural process of vascular pruning that takes place whenever VEGF, acting as a vascular survival factor, is downregulated below the level required to sustain immature vessels. Immature vessels are particularly vulnerable and are selectively obliterated upon withdrawal of VEGF. The plasticity window for vessel regression is determined by a delay in the recruitment of periendothelial cells to the preformed endothelial plexus. Thus fine-tuning of microvascular density takes place mostly in the newly formed plexus, but the mature system is refractory to episodic changes in tissue oxygenation. These regulatory links may malfunction in certain pathological settings.

Animals↗
PubMed1999

Clinical and inflammatory effects of dietary L-arginine in patients with intractable angina pectoris.

We evaluated the effects of oral L-arginine on the clinical outcome and the inflammatory markers of patients with intractable angina pectoris. Our findings demonstrated a significant clinical improvement in 7 of 10 patients, which was associated with a significant decrease in cell adhesion molecule and proinflammatory cytokine levels. Dietary L-arginine may have clinical beneficial effects in patients with intractable angina pectoris, and may have anti-inflammatory properties.

Administration, Oral↗
PubMed1999

Chloramine and copper sulfate as control agents of planktonic larvae of Chironomus luridus in water supply systems.

The latest approach to control of midge larvae in drinking-water supplies is suppression of the planktonic 1st-stage larvae, by using 2 disinfectants, chloramine and copper sulfate. The median lethal concentration for 24-h exposure of the 1st-stage larvae of Chironomus luridus to chloramine and copper sulfate individually was 0.51 and 0.38 mg/liter, respectively. The increase of copper sulfate to 0.5 mg of copper per liter to water containing chloramine (0.5 mg/liter) created a synergistic reaction that resulted in 96% (+/-8% SD) mortality of the planktonic larvae. This treatment may serve as an effective control of 1st-stage larvae in municipal drinking-water supplies.

Animals↗
PubMed1998

Arabidopsis SKP1, a homologue of a cell cycle regulator gene, is predominantly expressed in meristematic cells.

The yeast SKP1 gene and its human homolog p19skp1 encode a kinetochore protein required for cell cycle progression at both the DNA synthesis and mitosis phases of the cell cycle. In orchids we identified a cDNA (O 108) that is expressed in early stages of ovule development and is homologous to the yeast SKP1. Based on the orchid O 108 cDNA clone, we identified and characterized an Arabidopsis thaliana (L.) Heynh. cDNA designated ATskp1 that also has high sequence similarity to yeast SKP1. The Arabidopsis ATskp1 is a single-copy gene that mapped to chromosome 1. The expression of the ATskp1 gene was highly correlated with meristem activity in that its mRNA accumulated in all of the plant meristems including the vegetative shoot meristem, inflorescence and floral meristems, root meristem, and in the leaf and floral organ primordia. In addition, ATskp1 was also highly expressed in the dividing cells of the developing embryo, and in other cells that become multinucleate or undergo endoreplication events such as the endosperm free nuclei, the tapetum and the endothelium. Based on its spatial pattern of expression, ATskp1 is a marker for cells undergoing division and may be required for meristem activity.

Arabidopsis↗
PubMed1998

Shock chloramination: potential treatment for Chironomidae (Diptera) larvae nuisance abatement in water supply systems.

In the early 1990s, infestations of midge larvae (Chironomidae, Chironomus sp.) were discovered in the potable water system of Tel Aviv, Israel. Control measures, such as draining and cleaning tanks, spraying water into the tank's air space, and electrocution traps of midge adults, were either inadequate or ineffective. In this system, monochloramine concentrations of up to 0.75 mg/liter are used routinely as a secondary disinfectant. This chemical was tested in the laboratory as a toxicant of midge larvae. The mortality of 4th instar midge larvae after short exposure to high chloramine concentrations (LC50 values of 32 mg/liter for 75 min) suggested the efficacy of instituting a Shock Chloramination treatment program. Tanks were partially drained until they contained only 20 cm of water and were then temporarily disconnected. Chloramine was added to this water to produce a concentration of approximately 70 mg/liter for 1-2 h. Subsequently, all dead chironomids were flushed out, and the tank was refilled to attain the operational volume of water. A 2nd identical treatment of water in the tank was suggested 7 d later to kill midges from reproductive adults and egg-masses that survived the 1st treatment. This treatment program was tested in commercial covered tanks and gave complete control of these pests for 6-10 wk. These results suggest that this treatment program may effectively prevent midge outbreaks in Israel's drinking water supply system during the height of the summer.

Animals↗
PubMed1998

PNZIP is a novel mesophyll-specific cDNA that is regulated by phytochrome and the circadian rhythm and encodes a protein with a leucine zipper motif.

We isolated and characterized a novel light-regulated cDNA from the short-day plant Pharbitis nil that encodes a protein with a leucine (Leu) zipper motif, designated PNZIP (Pharbitis nil Leu zipper). The PNZIP cDNA is not similar to any other gene with a known function in the database, but it shares high sequence homology with an Arabidopsis expressed sequence tag and to two other sequences of unknown function from the cyanobacterium Synechocystis spp. and the red alga Porphyra purpurea, which together define a new family of evolutionarily conserved Leu zipper proteins. PNZIP is a single-copy gene that is expressed specifically in leaf photosynthetically active mesophyll cells but not in other nonphotosynthetic tissues such as the epidermis, trichomes, and vascular tissues. When plants were exposed to continuous darkness, PNZIP exhibited a rhythmic pattern of mRNA accumulation with a circadian periodicity of approximately 24 h, suggesting that its expression is under the control of an endogenous clock. However, the expression of PNZIP was unusual in that darkness rather than light promoted its mRNA accumulation. Accumulation of PNZIP mRNA during the dark is also regulated by phytochrome, since a brief exposure to red light in the middle of the night reduced its mRNA levels. Moreover, a far-red-light treatment at the end of day also reduced PNZIP mRNA accumulation during the dark, and that effect could be inhibited by a subsequent exposure to red light, showing the photoreversible response attributable to control through the phytochrome system.

Amino Acid Sequence↗
PubMed1996

Plasma cytokines, cytokine antagonists, and disease progression in African women infected with HIV-1.

OBJECTIVES: To examine the relation of circulating cytokines and cytokine antagonists to the progression of human immunodeficiency virus type 1 (HIV-1) disease. DESIGN: Cross-sectional analysis. SETTING: An ambulatory acquired immunodeficiency syndrome (AIDS) research clinic in Kinshasa, Zaire. PATIENTS: 48 women with AIDS, 51 women with HIV infection who were clinically asymptomatic, and 11 female controls who did not have HIV infection, all from Zaire. MEASUREMENTS: Plasma levels of interleukin-1beta, tumor necrosis factor-alpha (TNF-alpha), interleukin-6, interleukin-8, interferon-gamma, interleukin-1beta receptor antagonist (interleukin-1Ra), and TNF soluble receptor p55 (TNFsRp55) were assayed by specific radioimmunoassays. Plasma levels of interferon-gamma were assayed by commercial enzyme-linked immunosorbent assay. The Wilcoxon rank-sum test was used to assess the significance of mean and median differences between groups. RESULTS: Of the 48 patients with AIDS, circulating interleukin-1beta was detected in 2, TNF-alpha in 4, interleukin-6 in 3, and interleukin-8 in 12. None of these factors were seen in any of the 11 controls. Median values of interleukin-1beta (320 pg/mL), TNF-alpha (210 pg/mL), and interleukin-8 (750 pg/mL) were elevated in HIV-infected asymptomatic patients compared with patients with AIDS (2-, 2.6-, and 18.7-fold higher, respectively; P < 0.001). Interleukin-1Ra and TNFsRp55 levels were substantially higher than interleukin-1beta and TNF-alpha levels in HIV-infected asymptomatic patients (73- and 14-fold, respectively) and were higher than those in patients with AIDS (17.8- and 1.74-fold, respectively). CONCLUSION: High circulating levels of the proinflammatory cytokines interleukin-1beta and TNF-alpha, combined with an excess of their natural inhibitors interleukin-1Ra and TNF-sRp55, were seen in clinically asymptomatic HIV-1-positive African women but not in African women with AIDS or in HIV-negative controls. Circulating cytokine antagonists may play a clinical role in modulating cytokine-associated symptoms in the early phases of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Identification of a meristem L1 layer-specific gene in Arabidopsis that is expressed during embryonic pattern formation and defines a new class of homeobox genes.

Homeobox genes are master regulatory genes that specify the body plan and control development of many eukaryotic organisms, including plants. We isolated and characterized a cDNA designated ATML1 (for Arabidopsis thaliana meristem L1 layer) that encodes a novel homeodomain protein. The ATML1 protein shares high sequence homology inside and outside of the homeodomain with both the Phalaenopsis O39 and the Arabidopsis GLABRA2 (GL2) homeodomain proteins, which together define a new class of plant homeodomain-containing proteins, designated HD-GL2. The ATML1 gene was first expressed in the apical cell after the first asymmetric division of the zygote and continued to be expressed in all proembryo cells until the eight-cell stage. In the 16-cell proembryo, the ATML1 gene showed a distinct pattern of expression, with its mRNA becoming restricted to the protoderm. In the torpedo stage of embryo development, ATML1 mRNA disappeared altogether but reappeared later only in the L1 layer of the shoot apical meristem in the mature embryo. After germination, this L1 layer-specific pattern of expression was maintained in the vegetative shoot apical meristem, inflorescence, and floral meristems, as well as in the young floral organ primordia. Finally, ATML1 mRNA accumulated in the protoderm of the ovule primordia and integuments and gradually became restricted in its expression to the endothelium surrounding the embryo sac. We propose that ATML1 may be involved in setting up morphogenetic boundaries of positional information necessary for controlling cell specification and pattern formation. In addition, ATML1 provides an early molecular marker for the establishment of both apical-basal and radial patterns during plant embryogenesis.

Amino Acid Sequence↗
PubMed1996

Methylene blue-induced phototoxicity: an unrecognized complication.

OBJECTIVE: To describe photosensitization after prenatal exposure to a toxic amount of methylene blue and to alert pediatricians that, in a review of the literature, photosensitization (which this dye is capable of) has not been reported as a complication of prenatal exposure. DESIGN AND PATIENTS: A descriptive report of physical findings and significant laboratory tests in a very low birth weight preterm infant with prenatal exposure to methylene blue and a comparison of this reported case with previously described patients' complications and treatment. SETTING: Neonatal intensive care unit. INTERVENTION: Monitoring of laboratory tests to assess for methylene blue toxicity: two exchange transfusions for methemoglobinemia, hemolytic anemia, and hyperbilirubinemia; phototherapy for hyperbilirubinemia; and pathologic examination of skin bullae. RESULTS: Within hours of exposure to phototherapy, redness developed on all exposed areas of the patient's skin (which was initially deep blue), followed by bullae and desquamation of about 35% of the total skin surface area. The desquamation of erythematous areas continued even after discontinuation of phototherapy. Complete re-epithelialization was attained by 3 weeks of age. In addition to this newly observed complication, the patient had other previously described toxic effects. CONCLUSION: We have reported a previously unrecognized complication associated with high prenatal exposure to methylene blue and treatment with phototherapy. Methylene blue phototoxicity may be related to the high prenatal dose of the dye relative to patient's small size and young gestational age.

Anemia, Hemolytic↗
PubMed1996

Cytokine production by human peripheral blood mononuclear cells stimulated by a Pseudomonas aeruginosa culture filtrate: role of plasma and polymyxin B.

The lack of consensus regarding the significance of transmembrane passage of bacterial products across hemodialysis membranes can be related to several methodological differences in the various studies, including the choice of circulating fluid in the blood compartment of the model, nature and concentration of the bacterial products employed to challenge the dialysate compartment and whether cytokine production by PMBC or the limulus amebocyte lysate (LAL) assay was used as the index of transfer and the cytokine used as the read-out. In this study, we examined the production of interleukin-1 alpha (IL-1 alpha), interleukin-1 receptor antagonist (IL-1Ra) and interleukin-8 (IL-8) by peripheral blood mononuclear cells (PBMC) incubated with a Pseudomonas aeruginosa culture filtrate. Further, the effects of 10% autologous human plasma and Polymyxin B sulfate (PmB) on cytokine production by PBMC were also characterized. The results of our study indicate that the Ps. aeruginosa culture filtrate had both PmB suppressible and PmB non-suppressible components and that the addition of 10% human plasma significantly enhanced cytokine production by both PmB suppressible and PmB non-suppressible components. The enhancing effect of plasma was most evident at low concentrations of the filtrate. The inhibitory effect of PmB was most evident in samples cultured in the presence of 10% plasma. There was a direct correlation between the production of IL-1 alpha and IL-1Ra suggesting that both pro-inflammatory cytokines and cytokine-specific inhibitory proteins are concurrently produced. There results have direct relevance to selection of study conditions for in vitro models used to study the transmembrane passage of bacterial products across hemodialysis membranes.

Anti-Bacterial Agents↗
PubMed1996

Transfer of cytokine-inducing bacterial products across hemodialyzer membranes in the presence of plasma or whole blood.

Cytokine production by peripheral blood mononuclear cells (PBMC) is a sensitive indicator of cytokine-inducing substances which may cross from contaminated dialysate into the blood compartment. The objective of this study was to compare the transfer of cytokine-inducing substances from dialysate contaminated with a culture filtrate from Pseudomonas aeruginosa across dialyzers with low (hemophan) or intermediate ultrafiltration coefficients (modified cellulose triacetate, CTA), under conditions where either 10% plasma or whole blood was circulated in the blood compartment. Eight paired experiments of in vitro dialysis were carried out at 37 degrees C using a countercurrent recirculating loop dialysis circuit with either a new CTA or hemophan dialyzer. 10% plasma in standard tissue culture medium was circulated through the blood compartment and bicarbonate dialysate was circulated in the dialysate compartment. The dialysate was challenged sequentially by log-fold dilutions (10(2), 10(3) or 10(4)) of a Ps. aeruginosa culture filtrate. Samples were drawn from the blood compartment 5 and 15 minutes after each challenge and incubated with suspensions of PBMC in the absence or presence of polymyxin B, in order to block endotoxin. After 24 h at 37 degrees C, total interleukin-1 alpha (IL-1 alpha) was measured by RIA. Although the dialysate contained potent cytokine-inducing substances, there was no significant IL-1 alpha production by PBMC incubated with the plasma mixture from the blood compartment in the majority of experiments with both dialyzers and with each of the three dilutions of the bacterial challenge. Eight experiments were also performed with CTA dialzyers using heparinized whole blood in the blood compartment. Samples of whole blood and dialysate were drawn at baseline, after one hour of dialysis with uncontaminated dialysate and 15 minutes and three hours after dialysis with dialysate contaminated with Ps. aeruginosa filtrate. There was no significant IL-1 alpha production by PBMC isolated from the whole blood 1 h after dialysis with uncontaminated dialysate, and 15 min and 2 h after adding the Ps. aeruginosa filtrate to the dialysate side. In contrast, production of IL-1 alpha by PBMC from the same donors incubated with samples from the dialysate were 263 +/- 50, 1074 +/- 306, 2333 +/- 774 and 2602 +/- 702 pg/2.5 x 10(6) PBMC, respectively at the same four time points. These data suggest that although the Ps. aeruginosa culture filtrate present in the dialysate was a potent inducer of IL-1 alpha, neither dialyzer permitted transfer of cytokine inducing substances from the dialysate into the blood compartment.

Bacterial Toxins↗
PubMed1995

Glycosylated recombinant human tumor necrosis factor binding protein-1 reduces mortality, shock, and production of tumor necrosis factor in rabbit Escherichia coli sepsis.

OBJECTIVE: To examine the effect of glycosylated recombinant human tumor necrosis factor binding protein-1 (r-hTNF binding protein-1), the extracellular domain of the tumor necrosis factor receptor p55 produced in mammalian cells, in a rabbit model of circulatory shock due to Escherichia coli. DESIGN: Prospective, randomized, controlled trial. SETTING: University hospital research laboratory. SUBJECTS: Eighteen female, New Zealand white rabbits. INTERVENTIONS: Anesthetized rabbits, infused with E. coli (10(9) organisms/kg), were pretreated with either r-hTNF binding protein-1 or saline. Mean arterial pressure, central venous pressure, cardiac output, and heart rate were recorded every 20 mins for 1 hr before, and for 4 hrs after, the infusion of E. coli. Blood samples were obtained at 1-hr intervals for platelet count and white blood cell count, r-hTNF binding protein-1, and tumor necrosis factor (TNF) measurements. MEASUREMENTS AND MAIN RESULTS: Administration of r-hTNF binding protein-1 resulted in improvement of mean arterial pressure, cardiac output, and systemic vascular resistance, as compared with the vehicle-treated group (p < .05). Treatment with r-hTNF binding protein-1 was associated with 100% survival, as compared with 55.6% of the saline-treated rabbits (p < .05). Approximately 85% of r-hTNF binding protein-1 was cleared from the circulation 1 hr after the bolus injection (from 171 +/- 27 micrograms/mL at time = 0, to 27 +/- 4 micrograms/mL at 60 mins, decreasing to 6 +/- 2 micrograms/mL for the next 3 hrs). The r-hTNF binding protein-1-treated rabbits had lower serum TNF bioactivity during the first 2 hrs (p < .01). The decreased bioactivity of TNF was confirmed by a specific radioimmunoassay for rabbit TNF. However, at 4 hrs, the vehicle-treated rabbits had lower serum bioactive TNF concentrations (p < .05). The decrease in TNF concentrations in the r-hTNF binding protein-1-treated rabbits resulted from decreased production and, in part, from carry-over of r-hTNF binding protein-1 into the bioassay. CONCLUSIONS: Treatment with r-hTNF binding protein-1 improved hemodynamic variables and survival of E. coli-challenged rabbits. Administration of r-hTNF binding protein-1 suppressed bioactivity of TNF in the circulation of these rabbits, and the production of TNF as well.

Animals↗
PubMed1995

Antibody response of low birth weight infants to Haemophilus influenzae type b polyribosylribitol phosphate-outer membrane protein conjugate vaccine.

OBJECTIVE: To evaluate the effectiveness in low birth weight (LBW) infants of the currently recommended immunization schedule for conjugated Haemophilus influenzae type b (HIB) vaccine. METHODS: We quantified antibody responses in 36 preterm infants with a mean birth weight of 1060 g and a mean gestational age of 28 weeks. Infants were immunized with 0.5 mL of HIB vaccine at 2 and 4 months' postnatal age. Specific HIB antibodies were quantified on cord blood, immediately before each immunization and 2 months after the last immunization. RESULTS: Even though the geometric mean titers increased significantly during the study period, they were still markedly lower than values reported in term infants. After the second immunization, only 24 infants (67%) attained antibody concentrations of more than 0.25 micrograms/mL, defined as seropositivity. Also, only 53% of infants achieved antibody concentrations of more than 1.0 micrograms/mL compared with 92% as reported in term infants. Stepwise logistic regression identified gestational age of 27 weeks or less and the amount of intravenous immunoglobulin received as the significant variables influencing the antibody response after the first immunization. The incidence of side effects was negligible. CONCLUSIONS: We conclude that LBW infants, and especially those born at 27 or less weeks' gestation, do not respond as effectively to the HIB vaccine. We speculate that reevaluation of the current immunization schedule may be required for very LBW infants.

Antibodies, Bacterial↗