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Biomedical subjects

J W Robinson

Publications and source records attributed to J W Robinson.

At least 37 records · Page 2Linked to original sources
PubMed1996

Undetectable IgE responses after respiratory syncytial virus infection.

Sequential nasopharyngeal secretions were collected from 81 infants from one day to three months after admission to hospital with respiratory syncytial virus (RSV) infection. Samples from 21 infants were assayed for anti-RSV IgE in an antigen capture ELISA assay. No IgE antibodies were detected although an assay of IgA antibodies carried out in parallel by a similar technique detected IgA antibodies in the secretions of all patients tested. Neither prior absorption of IgA or IgG, concentration of the secretions by freeze drying, nor enzyme amplification of the assay revealed any virus specific IgE. Using an antibody capture ELISA with a sensitivity of 0.85 IU/ml, IgE could be detected in sequential secretions of only one of the 81 RSV infected infants studied. Further testing of the secretions from 12 of these patients and those of a further 15 using an enzyme amplified assay with a sensitivity of 0.1 IU/ml revealed no further positives. Low concentrations of IgE were found in the sera of the majority of infants with RSV infection but they did not differ from those of virus negative children of a similar age collected between RSV epidemics. No rise in mean serum IgE concentrations between acute and convalescent samples was observed. No virus specific IgE was detected in the sera of any infant using the enzyme amplified antigen capture ELISA.

Antibodies, Viral↗
PubMed1996

Control of Aedes albopictus in waste tire piles with reduced rates of temephos-treated granules.

Two days following treatment, larval populations of Aedes albopictus in waste tires treated with granular formulations of temephos were reduced 90% at the 0.11 kg AI/ha rate, 98% at the 0.56 kg AI/ha rate, and 100% at the 1.12, 11.21, and 22.42 kg AI/ha rates. Nearly 100% control was achieved for 8 wk at the 0.5 kg AI/ha rate, for 7 wk at the 1.12 kg AI/ha rate in one replicate, and for at least 5 months at the 11.21 and 22.42 kg AI/ha rates. These results indicate that prolonged control can be achieved with granular formulations at half (11.21 kg/ha) the maximum label rate and that excellent immediate control can be expected at 2.5% the maximum label rate.

Aedes↗
PubMed1995

The combined use of DSC and TGA for the thermal analysis of atenolol tablets.

The New York Regional Laboratory's forensic pharmaceutical group used thermal analysis (TA) to ensure adherence to batch formulations by drug manufacturers. TA in our laboratory consisted of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC and TGA were used to analyse finished dosage forms and their components. In this study the components of atenolol formulations were qualitatively identified by analysing individual components and comparing with the finished product. DSC and TGA were used together to develop a profile of batch formulations, with each analytical technique giving complementary types of information. For example, the excipient sodium starch glycolate was identified by DSC and confirmed by TGA. These experimental results demonstrated the use of TA for the characterization of finished dosage forms and the qualitative identification of some of the individual components in batch formulations.

Atenolol↗
PubMed1994

Biological activity, binding site and affinity of monoclonal antibodies to the fusion protein of respiratory syncytial virus.

The neutralizing activity and fusion-inhibition activity per unit weight of immunoglobulin were determined for each of a panel of 20 monoclonal antibodies (MAbs) to the fusion (F) protein of respiratory syncytial (RS) virus. Neutralization did not correlate with fusion-inhibiting activity, suggesting that the F protein plays at least two independent, antibody-sensitive roles in viral infection. Antibodies with the highest biological activity against A2, a subgroup A strain of RS virus, neutralized a subgroup B strain (8/60) poorly, suggesting a degree of antigenic variation that may be important in human infection. All but one fusion-inhibiting MAb bound to protein blots and binding was mapped to two areas on overlapping F protein fragments. One MAb with relatively poor fusion-inhibiting activity bound only to fragments C-terminal of amino acid 384, the remainder bound only to fragments containing residues 253 to 289. MAbs directed to the latter site were heterogeneous in neutralizing activity, subgroup specificity and fusion-inhibiting activity. These variations between MAbs could not be accounted for by differences in their binding avidities. We suggest that this binding site is not the complete antibody epitope which probably includes conformation-dependent elements.

Animals↗
PubMed1993

Binding of neutralizing monoclonal antibodies to regions of the fusion protein of respiratory syncytial virus expressed in Escherichia coli.

cDNA containing the entire coding sequence of the respiratory syncytial (RS) virus fusion (F) protein gene (574 amino acids) and two large PstI restriction fragments, encoding amino acids 18 to 212 and 214 to 574, were expressed in Escherichia coli as C-terminal chimeras with beta-galactosidase (beta-gal) in the pEX expression vector system. A further cDNA fragment, overlapping the PstI restriction site and encoding amino acids 190 to 289, was derived by PCR and expressed in a similar manner. Polyclonal rabbit serum raised against RS virus bound to all four chimeric proteins but most strongly to those containing C-terminal sequences. Two monoclonal antibodies (MAbs), 1E3 and RS348, capable of neutralizing the virus and inhibiting the viral fusion function, bound to all chimeras except that derived from the N-terminal PstI fragment, suggesting that their binding sites were located between amino acids 214 and 289. Further analysis of binding to expressed fragments from restriction enzyme digests and PCR amplification demonstrated that both antibodies bound to amino acids 253 to 289. MAb RS348 bound to 12-mer overlapping synthetic peptides containing the sequence 265 to 272 (PITNDQKK) but MAb 1E3 failed to bind to any 12-mer peptide derived from the F protein sequence. Immunization of mice with chimeric proteins containing the whole F protein coding sequence or amino acids 253 to 384, which includes the binding site of the two MAbs identified here, failed to induce antibodies that recognized the native RS virus F protein or could neutralize the virus. This suggests that either the beta-gal partner inhibits the immune response to the protein or that elements missing from the protein expressed in E. coli, perhaps conformational or added post-translation, contribute to the neutralizing antibody epitope.

Amino Acid Sequence↗
PubMed1991

A randomized trial of an interim methadone maintenance clinic.

BACKGROUND: Interim methadone maintenance has been proposed as a method of providing clinically effective services to heroin addicts waiting for treatment in standard comprehensive methadone maintenance programs. METHODS: A clinic that provided initial medical evaluation, methadone medication, and AIDS education, but did not include formal drug abuse counseling or other social support services was established in New York City. A sample of 301 volunteer subjects recruited from the waiting list for treatment in the Beth Israel methadone program were randomly assigned to immediate entry into the interim clinic or a control group. RESULTS: There were no differences in initial levels of illicit drug use across the experimental and control groups. One-month urinalysis follow-up data showed a significant reduction in heroin use in the experimental group (from 63% positive at intake to 29% positive) with no change in the control group (62% to 60% positive). No significant change was observed in cocaine urinalyses (approximately 70% positive for both groups at intake and follow-up). A higher percentage of the experimental group were in treatment at 16-month follow-up (72% vs 56%). CONCLUSIONS: Limited services interim methadone maintenance can reduce heroin use among persons awaiting entry into comprehensive treatment and increase the percentage entering treatment.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Menstrual cycle phase is a potential confound in psychophysiology research.

Effects of menstrual cycle phase on physiological levels and reactivity were studied in a within-subject design with 20 women aged 18-30 years. Basal body temperature was monitored daily; follicular and luteal recording sessions occurred before and after the ovulatory temperature rise, respectively. The design consisted of task and rest periods, presented in counterbalanced order across phases. Half the subjects began during their follicular phase and half began during their luteal phase. Follicular and luteal phases were compared for differences between baseline resting levels, as well as for reactivity. The results showed menstrual phase differences in heart rate, pulse transit time, and EEG alpha, particularly during tasks, but no difference in reactivity. Habituation effects in the group that began during the follicular phase often masked luteal activation. In spite of the fact that not all statistical results achieved significance, the consistency of most trends supports the conclusion that physiological recording sessions with women might best be restricted to the follicular phase.

Adult↗
PubMed1987

A comparison of three approaches for the determination of baseline levels of physiological activity.

The traditional means of determining baseline levels of physiological activity in research evaluating responses to stressful stimuli has been to record activity during rest periods either before or interspersed with periods of stimulation. Subjects may, however, anticipate the impending stimulation, thus elevating their levels of physiological activity even during periods of presumed rest. Eight physiological responses--forehead muscle tension, heart rate, heart rate variability, skin resistance level and non-specific responses, systolic and diastolic blood pressure, and pulse transit time--were recorded from 39 subjects during sessions which included both task and rest periods, and during sessions with only rest periods and periods of viewing slides of restful scenery. The results indicate a significant decrease in levels of physiological activity in most of the 8 physiological measures when activity was recorded during sessions in which no tasks were presented. The lowest levels of physiological activity were recorded while subjects viewed slides. These results suggest that the traditional approach to the determination of baseline may yield levels of physiological activity contaminated by anticipation of upcoming stimuli.

Adolescent↗
PubMed1987

The stability of physiological reactivity over multiple sessions.

Although individual response stereotypy (IRS) has been a subject of research for many years, the stability of the phenomenon, though often assumed, has not been adequately proven. The present study evaluated stability of reactivity profiles of eight variables (heart rate, heart rate variability, integrated muscle tension, skin resistance level, skin resistance response, systolic blood pressure, diastolic blood pressure, and pulse transit time) over four sessions of laboratory tasks in comparison to two subsequent sessions of rest periods. The two major characteristics of IRS--stability and uniqueness--were fulfilled. On the other hand, the first session was found to be an inadequate predictor of the stable composite profiles. Thus the IRS profiles which are determined from multiple observations over time are different from those which are calculated in the traditional manner with a single recording session.

Adolescent↗
PubMed1985

Mg2+-ATP-dependent sodium transport in inside-out basolateral plasma membrane vesicles from guinea-pig small intestinal epithelial cells.

The transport of sodium into inside-out basolateral plasma membrane vesicles from small intestinal epithelial cells has been examined. It was found, under equilibrium conditions, that binding of 22Na represents approx. 55% of the total uptake during an equilibration period of 30 min; 45% of the total uptake correspond to passive sodium entry in the vesicle space. In addition to binding and to passive Na+ entry, two distinct mechanisms capable of accumulating sodium in the intravesicular space can be demonstrated when ATP is added to the incubation medium. One transports sodium actively in the absence of potassium, whereas the other requires the presence of potassium in the interior of the vesicles. The two mechanisms can also be differentiated by their affinities for sodium, their optimal pH and by their behaviour towards different inhibitors. Thus, the mechanism that transports sodium in the absence of potassium is refractory to ouabain, but is inhibited by ethacrynic acid and furosemide, whilst the mechanism that accumulates sodium inside the vesicles in the presence of internal potassium is strongly inhibited by ouabain, is weakly inhibited by ethacrynic acid and is insensitive of furosemide. ATP is a specific stimulator of both processes, and the requirement for magnesium is absolute in both cases.

Adenosine Triphosphate↗
PubMed1985

Na+-stimulated ATPase activities in basolateral plasma membranes from guinea-pig small intestinal epithelial cells.

Two ATPase activities, a Na+-ATPase and a (Na+ + K+)-ATPase, have been found associated with sheets of basolateral plasma membranes from guinea-pig small intestinal epithelial cells. The specific activity of the former is 10-15% of the latter. The two ATPase activities differ in their affinity for Na+, their optimal pH, their K+ requirement and particularly in their behaviour in the presence of some inhibitors and of Ca2+. Thus the Na+-ATPase is refractory to ouabain but it is strongly inhibited by ethacrynic acid and furosemide, whilst the (Na+ + K+)-ATPase is totally suppressed by ouabain, partially by ethacrynic acid and refractory to furosemide. In addition, the Na+-ATPase is activated by micromolar concentrations of calcium and by resuspension of the membrane preparation at pH 7.8. The Na+-ATPase is only stimulated by sodium and to a lesser extent by lithium; however, this stimulation is independent of the anion accompanying Na+. The latter rules out the participation of an anionic ATPase. The relation between the characteristics of the sodium transport mechanism in basolateral membrane vesicles (Del Castillo, J.R. and Robinson, J.W.L. (1983) Experientia 39,631) and those of the two ATPase activities present in the same membranes, allow us to postulate the existence of two separate sodium pumps in this membranes. Each pump would derive the necessary energy for active ion transport from the hydrolysis of ATP, catalyzed by different ATPase systems.

Adenosine Triphosphatases↗
PubMed1983

Kinetics of the sodium/beta-methyl-D-glucoside co-transport system in the guinea-pig small intestine.

The kinetics of sodium-dependent beta-methyl-D-glucoside transport were examined in guinea-pig intestinal rings. Large-scale experiments were performed in which both sodium and monosaccharide concentrations were varied within the same animal. The results were evaluated by non-linear regression analysis, and an attempt was made to distinguish between the applicability of different models to describe the data set. Only two of the tested models provided a good fit to the data. These both involved the random formation of a ternary complex from either intermediate binary complex; in one, the constraint that only the ternary complex was able to cross the membrane was included, whereas in the other the ratio of the permeability coefficients for the binary complex between sugar and carrier and for the ternary complex was estimated. But this ratio did not differ significantly from zero, so the two acceptable models were equivalent. In addition, it was necessary to introduce into both these models the concept of a sodium reservoir at the surface of the brush-border membrane, such that the local sodium concentration in the vicinity of the carriers could never fall below a certain critical value (which was estimated at 4.8 mM), even in complete absence of this ion from the bulk medium.

Animals↗
PubMed1983

Functional and structural studies of ileal reservoirs used for continent urostomy and ileostomy.

The structure and function of the mucosa has been studied in continent ileostomy and urostomy reservoirs, the latter being a receptacle for diverted urine constructed out of ileal tissue. Morphometric evaluation was performed by a microdissection technique and functional studies involved the assessment of L-phenylalanine absorption by the whole pouch in vivo and the uptake of the same amino acid by biopsy samples in vitro. Endoscopic examination revealed fairly homogeneous villous structure in the ileostomy reservoirs. In the urostomies, there was a gradual appearance, as a function of the postoperative time interval, of areas of flat mucosa intermingled with villous regions. When possible, biopsies of the two types of mucosa were studied separately. Even in the villous regions of the urostomies, the size of the villi was smaller in all dimensions than the villi of ileostomy samples. The uptake of phenylalanine in vitro, however, was the same in villous samples from urostomies and in ileostomy biopsies. The absorption of phenylalanine in vivo by the whole pouch was lower in the urostomies. There was a good correlation between amino acid absorption in vivo and in vitro in the ileostomies, but not in the urostomies. This is attributed principally to the variable proportions of avillar and villous mucosa in the latter material, as there is a clear reduction in absorption in vivo in the longest established urostomy pouches.

Adult↗