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Biomedical subjects

B Hopkins

Publications and source records attributed to B Hopkins.

At least 55 records · Page 3Linked to original sources
PubMed1994

Mesh reinforcement increases bursting strength of intestinal anastomoses in steroid-treated rabbits.

We tested the hypothesis that reinforcement of small bowel anastomoses with polyglycolic acid mesh (PGAM) would increase bursting strength in steroid-treated subjects. Twenty-two New Zealand white rabbits weighing 3-4 kg received methylprednisolone 0.2 mg/kg/day IM for 7-13 days preoperatively and until killed 4-5 days postoperatively. Steroid effect was confirmed by a 58.3 per cent decrease in absolute lymphocyte count and a histologic reduction in anastomotic fibroblast proliferation and collagen deposition. Two small bowel anastomoses were performed in each animal using standard two-layer suture technique. One of the two anastomoses, randomly assigned, was circumferentially reinforced with PGAM such that each animal served as its own control. Anastomotic bursting pressures, determined on postoperative Day 4-5, were significantly higher in mesh-reinforced anastomoses (P = 0.003). Histologic examination of the reinforced anastomoses revealed a well-developed layer of fibroblasts and collagen between the PGAM and bowel wall serosa. These results demonstrate that polyglycolic acid mesh reinforcement significantly increases the bursting strength of small bowel anastomoses in steroid-treated rabbits.

Anastomosis, Surgical↗
PubMed1994

The use of minisatellite variant repeat-polymerase chain reaction (MVR-PCR) to determine the source of saliva on a used postage stamp.

In this paper we report the identification of an individual using the MVR-PCR technique on DNA extracted from single and multiple discs (3 mm) punched from a licked stamp attached to an envelope. The individual's code was successfully and uniquely matched to one already present within a database of 500 MVR codes which had been generated in a separate laboratory. The exercise illustrates the suitability of MVR-PCR for forensic samples and demonstrates the power of this rapid and novel identification system.

DNA, Satellite↗
PubMed1993

Human bradykinin B2 receptor: nucleotide sequence analysis and assignment to chromosome 14.

Functional cDNA clones for human bradykinin B2 receptor were isolated from uterus RNA by a polymerase chain reaction (PCR)-based method and by screening a human cosmid library with rat bradykinin B2 receptor probe. We isolated several overlapping clones from the cosmid library, each of which encodes the entire protein coding sequence. The human bradykinin B2 receptor gene codes for a 364-amino-acid protein with a molecular mass of 41,442 Da that is highly homologous to rat bradykinin B2 receptor cDNA (81%). The entire human cDNA sequence was cloned into an expression vector and mRNA was synthesised by in vitro transcription. Applications of bradykinin caused membrane current responses in Xenopus oocytes injected with the in vitro-synthesized mRNA. Preincubation with the potent B2 antagonist, HOE140, prevented this response. The genomic clone is intronless, and we have identified an upstream promoter region and a downstream polyadenylation signal. The human bradykinin B2 receptor gene has been mapped to chromosome 14 using PCR to specifically amplify DNA from somatic cell hybrids.

Amino Acid Sequence↗
PubMed1993

Qualitative changes in general movements and their prognostic value in preterm infants.

Qualitative assessments of general movements have been shown to have considerable power in predicting neurological outcomes in preterm infants with brain damage. In the present study such assessments were made in 35 preterm infants without major neurological problems before term age, born between 27 and 34 weeks gestation, of whom 12 were small-for-gestational-age (SGA). Most infants maintained a normal or (mildly) abnormal quality from 35 weeks postmenstrual age through 6, 12, 18 to 24 weeks corrected age. Seven changed from initially abnormal movements to a normal quality, six of them after 12 weeks. Differences between SGA and appropriate-for-gestational-age infants became less evident with age, particularly after 12 weeks. This was not the case when comparisons were made on the basis of gestational ages below or above 32 weeks. The prediction of neurological and mental outcomes at 1 year also improved after 12 weeks, around which age a major transformation in neural functions occurs. It is concluded that assessments of movement quality are particularly successful in predicting abnormal outcomes in comparison to examinations based on muscle tone and elicited responses.

Age Factors↗
PubMed1993

Mental and motor development in preterm infants: the issue of corrected age.

This paper addresses the question of whether corrected age needs to be applied to both the mental and motor development of preterm infants during the whole of the first year. A neglected problem in this respect is that a precise developmental index cannot be found with very low or very high raw scores. Using an alternative measure of performance (age equivalent deviation score), 36 preterm infants without serious medical or neurological problems were compared with 21 full-term infants on the Dutch version of the Bayley Mental Scale at the corrected ages of 12, 18, 24, 39 and 52 weeks and the Psychomotor Scale at 24, 39 and 52 weeks. Our findings suggest that full correction should be used in assessing the mental development of relatively healthy preterm infants during the second half of the first year. Assessments at earlier ages seem to overestimate the mental abilities of preterm infants, thus indicating that partial correction should be applied at these ages. For motor development during the second half of the first year a partial correction would seem more appropriate. The clinical implications of our findings are discussed.

Aging↗
PubMed1993

Development of muscle power in preterm infants: individual trajectories after term age.

In a longitudinal study individual trajectories were traced for the developing relationship between active and passive muscle power in preterm (n = 37) and fullterm (n = 20) infants from term to 24 weeks (corrected) age. Such trajectories should enable the identification of those infants at highest risk for later neurological dysfunctions. This contention is supported by the findings of this study: those preterm infants who showed marked discrepancies between the two sorts of muscle power or rigidity in both beyond 12 weeks corrected age were most likely to manifest neurological problems at 52 weeks of age.

Female↗
PubMed1993

A longitudinal study of neural maturation and early mother-infant interaction: a research note.

The development of postural control of the head and of looking towards and looking away from the mother is described; the age relationship between attainment of postural head control and looking towards the mother is investigated and the relation between smiling and "pleasure" vocalizations to looking towards and away is examined. Twelve normal, full-term mother-infant pairs participated in this home-based study. En face interaction was video-taped for maximally 15 min at 3, 6, 9, 12, 15 and 18 (or 21) weeks. We conclude that postural head control constitutes an important prerequisite for the emergence of socially directed behaviours during en face interaction.

Attention↗
PubMed1993

Effects of birthweight status and gestational age on the quality of general movements in preterm newborns.

It is hypothesised that individual differences in nervous system functioning, undetected by a neurological examination, are reflected in the quality of spontaneous movements of preterm newborns. Given this hypothesis it is expected that a short pregnancy duration and IUGR will be related to an abnormal movement quality. These expectations were confirmed in a group of 37 small-for-gestational-age and appropriate-for-gestational-age preterm newborns with gestational ages ranging from 27 to 34 weeks without serious perinatal complications and for whom no overt neurological abnormalities could be detected based on the evaluation of elicited responses and tonus at the postmenstrual age of 35 weeks. The quality of general movements was adversely affected by both IUGR and a pregnancy duration below 32 weeks. Newborns with an abnormal movement quality also had significantly lower obstetrical optimality scores. Previous research has shown these scores to be related to the neurological condition of the newborn. We conclude that observations of movement quality, being neither intrusive nor time consuming, may constitute a useful addition to the neurological assessment of preterm newborns without serious perinatal complications.

Birth Weight↗
PubMed1993

Pharmacological characterization of cloned human NK-2 (neurokinin A) receptor expressed in a baculovirus/Sf-21 insect cell system.

Using the novel ligand [4,5-3H-Leu9]neurokinin A ([4,5-3H-Leu9] NKA) in a receptor binding assay, we characterized the pharmacology of a cloned neurokinin NK-2 receptor from human lung (hNK-2R), expressed in baculovirus-infected Sf-21 insect cells. Functional hNK-2R cDNA clones were isolated from human lung using a polymerase chain reaction-based methodology. hNK-2R was cloned into pAcYM1, a vector designed to couple expression to the polyhedrin promoter, and the recombinant baculovirus was isolated and used to infect Sf-21 insect cells. hNK-2R expression levels were monitored by Northern blots and 125-I-NKA binding assays. Isolates demonstrating the highest specific binding of 125-I-NKA were grown and membrane preparations from high-speed centrifugations were prepared from both hNK-2R-expressing and wild-type virus-infected cells. [3H]NKA bound in a protein-dependent, saturable (Bmax = 820 +/- 167 fmol/mg of protein), and highly specific (88 +/- 5%) manner to hNK-2R, but not to membranes from cells infected with wild-type virus (14 +/- 8%, 7 +/- 10 fmol/mg of protein). [3H]NKA binding was rapid (k1 = 0.085 nM-1 x min-1) and reversible (t1/2 = 4-5 min). Equilibrium binding experiments demonstrated binding to a mixture of receptors in high and low affinity states (Kd1 = 2.28 +/- 0.26 nM and Kd2 = 266 +/- 91 nM). Binding to hNK-2R was greatly enhanced (400%-600%) by Ca2+ and Mg2+ (EC50 values of 30 microM and 140 microM, respectively), whereas guanosine-5'-O-(3'-thio)triphosphate and guanosine-5'-(beta, gamma-imido)diphosphate were inhibitory. Competition experiments with agonists also demonstrated binding to high and low affinity states, with the following order of potency: NKA > [Nle10]NKA(4-10) > [beta-Ala8]NKA(4-10) >> substance P; Senktide and the NK-1 antagonist CP96,345 (10 microM) did not inhibit binding. Inhibition of binding by selective NK-2 antagonists was consistent with a single affinity state and demonstrated the following order of affinity: SR48,968 >> MEN10,376 > L659,877 > R396. These data suggest that infection of Sf-21 cells with baculovirus expression vector harboring the cDNA of hNK-2R resulted in expression of high affinity, G protein-coupled hNK-2R, with pharmacological selectivity compatible with the NK-2A receptor subtype.

Animals↗
PubMed1992

A method to assess the development of muscle power in preterms after term age.

The purpose of this paper is to report a detailed description of an instrument for evaluating the development of active and passive muscle power in preterms beyond term age. The instrument is constructed on a basis of age-specific items that assess these two components of muscle power and on the assumption that a persistent discrepancy between them serves to detect those preterms at most risk for disturbances in motor development. The application of the instrument is illustrated by reporting the individual trajectories of five case studies without any serious medical complications. It is concluded that if a marked discrepancy between active and passive power persists beyond the corrected age of 3 months, then this may be a sign of underlying pathology which will eventuate in abnormal postural outcomes and thereby disturbances in the control and coordination of movement. Having now provided a detailed description of how this instrument should be applied in postterm follow-up of preterm infants, we are currently examining its sensitivity and specificity on a much larger sample of similar subjects.

Age Factors↗
PubMed1992

Development of the relationship between active and passive muscle power in preterms after term age.

Fifty-eight infants were assessed with an instrument which is designed to evaluate the development of the relationship between active and passive muscle power. The purpose of this longitudinal assessment was to investigate whether preterms show a different development course than fullterms in the relationship between these two components of muscle power. Thirty-seven low-risk preterms and twenty-one healthy fullterms were followed from term until 24 weeks corrected age. It is concluded that preterms differ markedly from fullterms in the developing interrelationship between active and passive muscle power. The value of the instrument for detecting signs of early pathology is discussed.

Age Factors↗
PubMed1992

Training supervisors in a collaborative team approach to promote peer interaction of children with disabilities in integrated preschools.

Three supervisors of integrated preschools were trained in a collaborative team approach to encourage resource and classroom teachers to develop strategies that promote peer interaction of all children, including children with disabilities. The focus of classroom teachers' behaviors and the interactive play of children with disabilities were measured daily in both a training (indoor play period) and a generalization (outdoor play period) setting. In a multiple baseline design, supervisors were individually trained in a collaborative team approach using a manual, modeling, and role playing; then they implemented the approach with classroom and resource teachers. We found that after supervisor training, classroom teachers increased their behaviors directed towards children with disabilities and decreased their behaviors directed towards nondisabled children. Moreover, we found a doubling of the interactive play of children with disabilities and, for two of the three classes, an increase in the interactive play of comparison children, randomly selected by the classroom teachers. Changes in both teachers' and children's behaviors were also found in the generalization setting. The implications of the results for interventions in community settings are discussed.

Child Behavior Disorders↗
PubMed1991

Isolation and characterisation of the human lung NK-1 receptor cDNA.

Functional cDNA clones for human NK-1 receptor were isolated from human lung RNA using the polymerase chain reaction (PCR). We have screened a human cosmid library and isolated a clone which appeared to contain the entire NK-1 receptor gene. From the published rat NK-1 receptor cDNA sequence we designed primers within the protein coding sequence, but outwards towards both the 5' and 3' ends of the putative human protein sequence. By this method we derived DNA sequence from the 3' end of the human gene. In order to determine the 5' end of the gene we used a PCR based method called Rapid Amplification of cDNA Ends (RACE). From the derived human sequences amplimers were designed upstream of the ATG initiation codon and downstream of the stop codon. The entire cDNA was obtained by RNA-PCR from human lung RNA. The sequence obtained was 407 amino acids in length, encoding an open-reading frame that was highly homologous to the rat NK-1 receptor cDNA (89%). The entire human cDNA was then cloned into a mammalian expression vector and mRNA was synthesized by in vitro transcription. Applications of tachykinins caused membrane current responses in Xenopus oocytes injected with the in vitro synthesized mRNA. The most potent of the three tachykinin peptides tested was Substance P. The human NK-1 receptor gene has been mapped to chromosome 2 using the polymerase chain reaction to specifically amplify the human sequence in hamster/human hybrid DNA and also in mouse/human monochromosome hybrids.

Aged↗
PubMed1991

Isolation and characterisation of the human lung NK-2 receptor gene using rapid amplification of cDNA ends.

Functional cDNA clones for human NK-2 receptor were isolated from human lung RNA using a polymerase chain reaction (PCR) based method (RACE-PCR). In this method the cDNA was isolated as 5' end and 3'-end fragments; the entire cDNA was obtained by RNA-PCR. The sequence derived was 398 amino acids in length encoding an open-reading frame that was highly homologous to both the bovine and rat NK-2 receptor. The entire human cDNA sequence was cloned into a mammalian expression vector and mRNA was synthesised by in vitro transcription. Applications of tachykinins caused membrane current responses in Xenopus oocytes injected with the in vitro synthesised mRNA. The most potent of the three tachykinin peptides tested was neurokinin A. We have screened a human cosmid library and isolated a clone which contains the entire NK-2 receptor gene. The gene contains five exons and we have determined the complete sequence of the exons and the intron-exon junctions.

Aged↗
PubMed1991

Human NK-2 receptor gene maps to chromosome region 10q11-21.

The human NK-2 receptor gene has been mapped to chromosome 10 using the polymerase chain reaction to amplify specifically the human NK-2 receptor sequence in hamster/human hybrid DNA and also in mouse/human monochromosome hybrids. The assignment to chromosome 10 was confirmed by in situ hybridisation to human metaphase chromosomes, giving a regional localisation of 10q11-21.

Base Sequence↗
PubMed1991

Use of DNA fingerprinting in paternity analysis of closely-related Exmoor ponies.

DNA fingerprinting techniques were used to try to resolve the parentage of an Exmoor pony foal. Three young Exmoor ponies, one female and two males, shared a paddock and the female subsequently became pregnant. The two possible sires were three-quarter siblings and were also half-siblings to the dam. Southern hybridisation of Exmoor pony DNA with human mini-satellite probes resolved the disputed parentage in spite of the fact that there was a 70 per cent band share between the individuals involved. Colt M6 was 2.06 times more likely to be the father than an uncle, and Colt M3 was 477 times more likely to be an uncle than the father.

Animals↗