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S L Hall

Publications and source records attributed to S L Hall.

At least 37 records · Page 2Linked to original sources
PubMed1993

Reference standards for quantification of skeletal alkaline phosphatase activity in serum by heat inactivation and lectin precipitation.

Putative standards of skeletal alkaline phosphatase (ALP) (from bone, bone cells, osteosarcoma cells, and Pagetic serum) and hepatic ALP (from cholestatic serum and bile) were used to compare three methods for quantifying skeletal ALP activity in serum: heat inactivation, precipitation with wheat germ agglutinin (WGA), and precipitation with concanavalin A (Con A). All the skeletal ALP standards were similarly sensitive to heat inactivation, as were the hepatic ALP standards. Heat inactivation separated skeletal from hepatic ALP by a 50% difference in remaining ALP activities (e.g., 23% and 74% remaining skeletal and hepatic ALP activities after 30 min at 52 degrees C). Differential precipitations with WGA and with Con A were less efficient at separating skeletal from hepatic ALP (maximum differences of < 30% remaining ALP activity). Although both types of hepatic ALP standard (cholestatic serum and bile) were precipitated with similar efficiencies by WGA and Con A, the skeletal ALP standards were not (e.g., at 2.7 g/L, WGA precipitated 78-86% of the ALP activity in Pagetic serum, but only 49% of the ALP activity in extracts of human bone). These data suggest that heat inactivation is preferable to precipitation with WGA or Con A for quantifying skeletal ALP activity in serum: it better separates skeletal from hepatic ALP activity and is not sensitive to glycosyl heterogeneity.

Alkaline Phosphatase↗
PubMed1992

The complete nucleotide sequence of the JS strain of human parainfluenza virus type 3: comparison with the Wash/47885/57 prototype strain.

The nucleotide sequence of the JS strain of human parainfluenza virus type 3 (PIV3) was determined from a series of 14 overlapping cDNA clones and was compared to that of the previously sequenced prototype PIV3 strain, Wash/47885/57 (Galinski, 1991). Overall, there were 630 (4%) nucleotide differences between the two viruses. 15462 nucleotides comprised the JS genome in contrast to 15463 which constituted the genome of the prototype virus. This was accounted for by a single nucleotide deletion in the 5' non-coding region of the JS phosphoprotein gene. Four nucleotide substitutions were found in the leader region at the 3' end of the viral genome at positions 24, 28, 42 and 45, whereas no differences were found in the 44 base trailer region. All of the transcription start and stop signals and intergenic sequences were conserved between the two viruses with the exception of the transcription stop signal of the matrix (M) gene where there was a nucleotide transposition between bases 7 and 8. A comparison of all of the nucleotide differences in the 3' and 5' non-coding regions of each gene showed a variability of 9.8% and 10.5%, respectively. The 3' non-coding regions of the nucleocapsid (NP) and M genes were completely conserved in contrast to the polymerase (L) gene in which 25% of the nucleotides were different. Differences were observed in the 5' non-coding regions of each gene and ranged from 5.9% for the hemagglutinin neuraminidase (HN) gene to 14.6% for the M gene. An analysis of the amino acid differences in each open reading frame revealed that of all the genes, the coding region of the M gene was the most highly conserved (1.1% amino acid variability), while the phosphoprotein (P) gene was the most variable (5.8% amino acid variability). As these two viruses are wild type strains, these differences in nucleotide and amino acid sequence are compatible with efficient replication in vivo.

Base Sequence↗
PubMed1992

Quantitation of skeletal alkaline phosphatase isoenzyme activity in canine serum.

Pursuing the hypothesis that quantitation of skeletal alkaline phosphatase (ALP) activity in canine serum would provide an index of the rate of bone formation, we compared three methods for isoenzyme-specific identification of skeletal ALP activity in canine serum: heat inactivation, wheat germ agglutinin (WGA) precipitation, and concanavalin A (ConA) precipitation. ALP isoenzyme activities were extracted from canine bone, intestine, and liver, diluted into heat-inactivated canine serum (i.e., serum without ALP activity), and used as calibrators of ALP isoenzyme activities. Differential sensitivity to inhibition by 10 mM L-homoarginine was used to distinguish intestinal ALP activity from hepatic and skeletal ALP activities (i.e., 9, 80, and 72% inhibition, respectively). To allow resolution of skeletal ALP activity from hepatic ALP activity, we tested two established methods (heat inactivation and WGA precipitation) and a novel method, ConA precipitation. The organ-derived skeletal and hepatic ALP isoenzyme activities were used to compare these three methods with respect to linearity, isoenzyme separation, and precision. All three methods were linear, but the WGA and ConA methods afforded greater isoenzyme separation and precision. The relative extent of isoenzyme separation (i.e., the difference in percentage remaining skeletal and hepatic ALP isoenzyme activities) averaged 23, 40, and 47% remaining ALP activity for the heat, WGA, and ConA methods, respectively. However, when these methods were applied to the quantitation of skeletal ALP activity in sera from 10 young and 10 adult beagles, the WGA method was found to be unacceptable because most of the results fell outside the range of the WGA assay calibrators (i.e., greater than 100% skeletal ALP activity). The heat and ConA methods showed that the amount of skeletal ALP activity in the beagle sera decreased with age, both as ALP activity per liter and as percentage of total serum ALP activity (p less than 0.001 for each). Skeletal ALP activity levels determined by ConA were correlated with values determined by heat inactivation (r = 0.87, p less than 0.001) but not with WGA-determined levels (r = 0.26). Intestinal ALP activity was detected in only 1 of these 20 sera. We conclude that ConA precipitation can be used for quantitation of skeletal ALP activity in beagle serum.

Alkaline Phosphatase↗
PubMed1992

Two biochemical indices of mouse bone formation are increased, in vivo, in response to calcitonin.

In a series of four studies, adult female Swiss-Webster mice were used to measure the effects of salmon calcitonin on two biochemical indices of local and systematic bone formation: (1) skeletal alkaline phosphatase activity--in serum and in extracts of calvaria and tibiae, and (2) calvarial collagenase-digestible protein synthesis--measured, acutely, in vitro. Subcutaneous calcitonin doses ranged from 50 to 400 mU/mouse/day (0.95-18.1 U/kg/day), and treatment schedules were continuous (daily) for 2-14 days, acute, or intermittent (2 days/week for 6 weeks). The effects of calcitonin on these bone formation indices (skeletal alkaline phosphatase and collagenase-digestible protein synthesis) were biphasic with respect to dose and treatment time, being increased in response to short-term, low-dose treatment, but not long-term, continuous treatment. The effects of long-term intermittent calcitonin treatment were dose-dependent increases in skeletal alkaline phosphatase in calvaria and serum (r = 0.948, P less than 0.02, and r = 0.960, P less than 0.01, respectively).

Alkaline Phosphatase↗
PubMed1992

Cold-passaged human parainfluenza type 3 viruses contain ts and non-ts mutations leading to attenuation in rhesus monkeys.

Cold-passaged (CP) mutants derived from the JS strain of wild type wt parainfluenza type 3 virus (PIV3) are being evaluated as candidate live virus vaccines. The wt virus was serially passaged 45 times at low temperature and mutant clones with the cold-adapted (CA), temperature-sensitive (ts), and attenuation (ATT) phenotypes were selected following passage levels 12, 18 and 45 (cp12, cp18, and cp45). The cp45 virus was more ts than the cp12 or cp18 mutants, although all 3 mutant viruses were clearly attenuated in rhesus monkeys compared to wild type virus. The mean peak titers of the cp12 and cp18 viruses administered by the intratracheal route were at least 6000-fold lower than JSwt in both the upper and lower respiratory tracts. The cp45 virus was not recovered from monkeys administered virus by the i.t. route alone; however, when the cp45 virus was administered by the intranasal route, it replicated in the upper respiratory tract to a level comparable to that of the cp12 and cp18 viruses, but continued to be markedly restricted in the lower respiratory tract. These data indicate that the cp12 and cp18 viruses contain predominantly non-ts attenuating mutations whereas the cp45 mutant has both non-ts and ts attenuating mutations. Each of the CP mutants induced a high level of resistance to wild type virus challenge. Also, the ATT phenotype of the cp12 and cp18 viruses as measured in rhesus monkeys was stable after replication in chimpanzees or humans, respectively, although the ts phenotype was not. Based on its greater level of temperature sensitivity in vitro and its greater degree of attenuation in rhesus monkeys, the cp45 virus appears to be the most promising vaccine candidate for humans.

Animals↗
PubMed1992

Evaluation of a live attenuated, cold-adapted parainfluenza virus type 3 vaccine in children.

Cold passage 18 (CP18) parainfluenza virus type 3 (PIV-3) vaccine was evaluated in a double-blind, randomized, placebo-controlled study of 95 infants and young children. None of 19 seropositive older children 41 to 124 months old became infected when 10(6) 50% tissue culture infective doses (TCID50) of vaccine virus was administered intranasally. Two of nine and seven of twenty-four young seropositive children given 10(5) or 10(6) TCID50 of CP18 PIV-3, respectively, became infected. Each of four seronegative young children became infected, as indicated by virus shedding and antibody response, when given 10(6) TCID50 of CP18 PIV-3 intranasally. Illness was not observed in seropositive children. Two of the four seronegative children developed a mild illness characterized by rhinorrhea and wheezing on auscultation; none had fever. In one case, vaccine virus spread from a vaccine to a sibling control but did not cause illness. The vaccine is attenuated relative to wild-type PIV-3, but additional attenuation will be required to achieve a satisfactory PIV-3 vaccine.

Adaptation, Physiological↗
PubMed1992

Intrapulmonary bacterial clearance of type III group B streptococcus is reduced in preterm compared with term rabbits and occurs independent of antibody.

Intrapulmonary clearance of type III group B streptococcus (GBS) and related phagocytic recruitment was studied in preterm and term rabbits at 4 and 8 h after aerosol infection using left lung homogenates to quantify GBS and right lung bronchoalveolar lavage (BAL) to recover phagocytes. Opsonophagocytosis of type III GBS by pulmonary alveolar macrophages (PAM) was studied in vitro with a modified differential fluorescence-quenching method using PAM lavaged from preterm, term, and adult rabbits. Sera of experimental animals were tested for opsonization of type III GBS using fluorescein-labeled antibodies to rabbit IgG and C3. Although term animals showed some clearance at 8 h, preterm animals had marked intrapulmonary proliferation of GBS. The number of PAM in BAL fluid was 20-fold higher in term than in preterm rabbits at 0 h, but by 8 h, preterm rabbits had a large influx of PAM, whereas PAM remained constant in term BAL fluid. Rates of phagocytosis of GBS were twice as high in term versus preterm PAM during in vivo and in vitro studies. Among PAM from term and adult animals, opsonization of GBS with MgEGTA-sera promoted phagocytosis in vitro at levels comparable to pooled adult sera, whereas opsonization with EDTA-sera resulted in a significantly lower rate of ingestion. None of the experimental animals' sera were able to deposit IgG, but all deposited C3 on the surface of GBS. In summary, preterm rabbits had a diminished bronchoalveolar PAM population that did not ingest GBS as well via the alternative complement pathway when compared with term rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Calcitonin has direct effects on 3[H]-thymidine incorporation and alkaline phosphatase activity in human osteoblast-line cells.

Calcitonin had direct and dose-dependent actions on human osteoblast-line cells (in serum-free monolayer culture) to increase cell proliferation and alkaline phosphatase activity/mg cell protein. Salmon calcitonin increased (human osteosarcoma) SaOS-2 cell proliferation, as evidenced by dose-dependent increases in 3[H]-thymidine incorporation into DNA (e.g., 153% of control after 20 h exposure at 0.1 nM, P less than 0.01), and MTT (thyzolyl blue) reduction/deposition (e.g., 161% of control after 72 h exposure at 0.03 nM). Continuous exposure was not required to elicit these proliferative responses. These effects were not unique to salmon calcitonin or to SaOS-2 cells. Similar effects were seen with human calcitonin (but not heat-inactivated human calcitonin) and with (human osteosarcoma) TE-85 cells and human osteoblast-line cells prepared from femoral heads. In addition to effects on cell proliferation, calcitonin also increased alkaline phosphatase-specific activity in SaOS-2 cells (e.g., 180% of control after 72 h of exposure to 0.1 nM salmon calcitonin, P less than .005).

Alkaline Phosphatase↗
PubMed1991

Skeletal alkaline phosphatase specific activity is an index of the osteoblastic phenotype in subpopulations of the human osteosarcoma cell line SaOS-2.

During continuous culture with serial passage, the human osteosarcoma cell line SaOS-2 showed a time-dependent decrease in skeletal alkaline phosphatase (ALP) activity. Because this was indicative of heterogeneity, subpopulations of SaOS-2 cells were isolated from replicate low-density cultures. The subpopulations were less heterogeneous and more stable (with respect to ALP) than the parent population. ALP specific activity in the subpopulations ranged from 0.05 to 2.3 U/mg protein, and cytochemical analyses indicated multiple steady-state levels of ALP activity per cell. The amount of ALP activity in SaOS-2 subpopulations was proportional to collagen production ([3H]proline incorporation into collagenase-digestible protein; r = .84, P less than .005), and to parathyroid hormone (PTH)-linked synthesis of cyclic adenosine monophosphate (cAMP) (r = .88, P less than .01). From these data, we inferred that ALP activity in SaOS-2 cells can provide a useful index of the osteoblastic phenotype, and that ALP activity, collagen production, and PTH-linked adenylate cyclase were coordinately regulated in these osteoblast-like osteosarcoma cells (ie, selection of subpopulations for ALP activity coselected for collagen synthesis and PTH-linked synthesis of cAMP). Further comparative studies showed that micromolar fluoride concentrations stimulated cell proliferation ([3H]thymidine incorporation into DNA) in low-ALP SaOS-2 subpopulations, but not in high-ALP cells (P less than .001), and that this differential sensitivity to fluoride was associated with an inverse correlation between fluoride-sensitive acid phosphatase and ALP activities (r = -.91, P less than .001).

Alkaline Phosphatase↗
PubMed1991

Protection of cotton rats by immunization with the human parainfluenza virus type 3 fusion (F) glycoprotein expressed on the surface of insect cells infected with a recombinant baculovirus.

The antigenicity, immunogenicity and efficacy of the human PIV3 fusion (F) glycoprotein expressed in insect cells by a baculovirus vector were studied. The results indicate that the PIV3 F glycoprotein expressed by a recombinant baculovirus is antigenically authentic as determined using a panel of PIV3 F specific monoclonal antibodies. Only a low level of antibody was stimulated by immunization of animals with infected cells, but the antibody appeared to be of high quality. Immunized animals were also moderately protected against PIV3 challenge. These results indicate that the baculovirus expression system is a reasonable source of authentic PIV3 F protein for use in a subunit vaccine.

Animals↗
PubMed1991

Maturational changes in endothelium-derived relaxing factor activity of ovine pulmonary arteries in vitro.

To examine mechanisms underlying fetal pulmonary vascular vasodilator responses and maturational changes in endothelial function, we studied effects of endothelium-dependent (acetylcholine, ACh: adenosine diphosphate, ADP; and A23187) and -independent (sodium nitroprusside, SNP) vasodilators on tone of small (third generation) pulmonary artery rings isolated from late-gestation fetal, newborn, and adult sheep. Changes in isometric force of phenylephrine-contracted rings were measured after the cumulative addition of vasodilators in baths aerated with 21% O2 and 5% CO2. Pulmonary artery rings from fetal lambs demonstrated minimal relaxation to ACh, ADP, and A23187, achieving only 17 +/- 3, 14 +/- 5, and 23 +/- 8% relaxation, respectively. In contrast, fetal rings relaxed completely (100%) to SNP. Rings from newborn and adult animals had significantly greater maximal relaxation in response to ACh. ADP, and A23187 than fetal rings (at least P less than 0.05 for each comparison with fetal rings), but responses to SNP were not different. Hemoglobin (10(-5) M), an inhibitor of endothelium-derived relaxing factor, caused less augmentation of phenylephrine contraction in fetal than adult pulmonary artery rings (11 +/- 4% vs. 49 +/- 8%; P less than 0.01). We conclude that in comparison with pulmonary artery rings from postnatal animals, fetal pulmonary artery rings have diminished endothelium-derived relaxation factor activity. We speculate that maturational changes in endothelial cell function contribute to ontogenetic differences in pulmonary vasoreactivity.

Acetylcholine↗
PubMed1991

Hemodynamic effects of endothelin-1 on ovine fetal pulmonary circulation.

To determine the hemodynamic effects of endothelin-1 (ET-1) in the fetal pulmonary circulation, we studied pulmonary vascular responses to brief and prolonged intrapulmonary infusions of the peptide in nine chronically prepared late-gestation fetal sheep. Left pulmonary artery (LPA) blood flow was measured with an electromagnetic flow transducer, and a catheter placed in the LPA allowed ET-1 infusion directly into the left lung. Brief (10-min) infusions of ET-1 (12.5-100 ng/min) increased flow up to 212% of baseline without changing pulmonary artery pressure. With prolonged (120-min) infusion of ET-1 (50 ng/min), flow increased from 69 +/- 8 to 164 +/- 23 ml/min at 10 min (P less than 0.05) but then declined and was not different from baseline at 120 min. The gradient between mean pulmonary artery and aortic pressures did not change, suggesting no constriction of the ductus arteriosus. Systemic (vena caval) infusion of ET-1 (100 ng/min for 30 min) caused systemic and pulmonary hypertension, as mean pulmonary artery pressure increased from 43 +/- 1 to 51 +/- 2 mmHg (P less than 0.05) and remained elevated for 30 min after cessation of the ET-1 infusion. We conclude that intrapulmonary ET-1 is a potent fetal pulmonary vasodilator, but its dilator effect is transient during prolonged infusion. In contrast, systemic infusion causes sustained hypertension, suggesting differential effects of ET-1 on the pulmonary and systemic circulations. These findings demonstrate marked vasoactivity of ET-1 in the fetus, suggesting a potential role in the normal or abnormal transitional circulation.

Animals↗
PubMed1990

Safety of intravenous immunoglobulin infusion in neonates at risk for sepsis.

Intravenous immunoglobulin (Gammagard 5%), 500 mg/kg, was given over 3 hours to 10 acutely ill infants with proven or suspected sepsis (treatment group) and 10 clinically stable preterm infants less than 1750 gm birthweight as prophylaxis for sepsis (prevention group). No differences were found in heart rate, respiratory rate, mean arterial blood pressure, or urine output in either group during or following the infusion compared with preinfusion values, except for a small but significant decrease in heart rate postinfusion in the prevention group. Likewise, serum glucose, sodium, serum glutamic oxaloacetic transaminase, and osmolality were unchanged 15 minutes and 6 hours following infusion. Urea nitrogen rose a small but significant amount in both groups. Hemoglobin concentration declined a small but significant amount 15 minutes postinfusion in the prevention group, but returned to baseline by 6 hours postinfusion. There were no changes in white blood cell count or platelet counts in either group. These data indicate that intravenous immunoglobulin in the dose given was associated with no adverse effects. Additional studies are warranted to evaluate the efficacy of these preparations in the treatment and prevention of neonatal septicemia.

Antibodies, Viral↗
PubMed1990

Relationship of maternal to neonatal colonization with coagulase-negative staphylococci.

Infections with coagulase-negative staphylococci (C-S) have become problems of major clinical importance among very low birthweight infants in neonatal intensive care units. Colonization with slime-producing strains of C-S may be a risk factor for these infants in the development of invasive infections. The present study evaluated the maternal genital tract as a possible source for neonatal colonization with C-S. Specific objectives were to determine the incidence of vaginal colonization with C-S in pregnant women with special reference to slime-producing strains and whether transmission of C-S occurs from mother to infant during the process of vaginal delivery. Antenatal vaginal cultures were done on 465 women at different gestations of pregnancy. Additionally, 101 women and their newborn infants were cultured after vaginal delivery. Fifty-one percent of women were colonized with C-S during pregnancy, and no significant differences in colonization rates by trimester were found. Slime-positive isolates from pregnant women increased significantly from the first to the third trimester (40 to 68%; chi-square, 11.21, p less than 0.005). However, the proportion of slime-positive strains among the 30 infants who were colonized with C-S at birth was 40% (12 of 30). Although 30 infants were colonized with C-S at birth, only three were shown to have acquired the organism by maternal transmission determined by similarity of species, biotype, antibiotic sensitivity pattern, slime production, phage type, and plasmid pattern profile. Therefore 27 infants (26% of the total) most likely acquired C-S from environmental sources, including nursery attendants.(ABSTRACT TRUNCATED AT 250 WORDS)

Coagulase↗