Search PubMed⌕ Search

Biomedical subjects

M Hall

Publications and source records attributed to M Hall.

At least 163 records · Page 9Linked to original sources
PubMed1994

Possible pathogenic role of IgE in Henoch-Schönlein purpura.

The incidences of clinical and biological markers of atopy were investigated in 16 children with IgA nephropathy (IgAN) (group A) and in 22 with Henoch-Schönlein purpura nephritis (HSPN) (group B). The incidence of increased plasma IgE levels according to age-matched normal values was significantly higher in group B (17/22, 77%) than in group A (7/16, 44%) (P < 0.05). Although not significant, the incidences of positive RAST tests and of a history of typical atopic symptoms were also higher in group B [10/22 (45%) and 11/22 (50%), respectively] than in group A [4/16 (25%) and 5/16 (31%), respectively]. Moreover, IgE deposits were demonstrated by a peroxidase/anti-peroxidase method on cutaneous Langerhans and mast cells in 4 of 6 patients with HSPN. Thus immunoallergy might account, in some cases, for the cutaneous, intestinal and pulmonary signs observed in HSPN, but not in IgAN. We postulate stimulation of IgE-sensitized mast cells by specific antigens in the presence of IgA circulating immune complexes (CIC), release of vasoactive substances, increased capillary permeability and perivascular deposition of IgA CIC.

Adolescent↗
PubMed1994

Effect of hyperfiltration on long-term follow-up of glomerular filtration rate in male Wistar rats.

It has been suggested that a prolonged course of hyperfiltration could lead to progressive deterioration of renal function. In order to test this hypothesis, the following protocol was applied to 60 male Wistar rats. At 12 weeks of life, the rats were submitted to a surgical procedure: sham operation (25 rats), unilateral nephrectomy (25 rats) or 3/4 nephrectomy (10 rats). The three groups were again divided into two subgroups: one with high-protein intake (36%) and one with a low-protein intake (12%). In order to avoid any additional traumatic procedure which could shorten the animal's life, the glomerular filtration rate (GFR) was measured without blood sampling, using a previously validated technique based on an image recorded by a gamma camera between the 9th and the 10th min after intravenous injection of 99m technetium diethylenetriaminepentaacetate (DPTA). The sum of both kidneys and bladder activity was expressed as a percentage of the injected dose. The test was performed before surgery and every month thereafter. Six weeks after surgery, the highest filtration rate was found in the rats with "two kidneys/high-protein diet", followed by the "two kidneys/low-protein diet", the "one kidney/high-protein diet", the "one kidney/low-protein diet" and the "1/2 kidney". The overall GFR in the one kidney/high-protein diet rat and in the 1/2 kidney rat was respectively 80% and 55% of the pre-operative values. Until 109 weeks of age, the survival rate was comparable in the five groups of rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Is antenatal care apportioned according to obstetric risk? The Scottish antenatal care study.

A retrospective cohort study of case records of antenatal care was carried out to describe and compare antenatal services in Scotland according to type of hospital and risk category of women. The study took place at 15 randomly selected maternity hospitals which were divided into teaching hospitals (n = 5), rural catchment hospitals (n = 2), and district general hospitals divided by size as those with 1000-1699 deliveries per year (n = 4), and those with > or = 1700 deliveries per year (n = 4). The subjects were 3574 (87.7 per cent) of 4069 eligible women who delivered in the last quarter of 1989 at these hospitals. Of those 3574, 19 per cent (675) were considered to be high risk at booking, 64 per cent (2899) continued low risk throughout their pregnancy and the remaining 17 per cent (608) changed from low risk to high risk during pregnancy. The main outcome measures were the number, timing, location and supervision of antenatal visits and antenatal admissions in relation to hospital types and obstetric risk categories, and adverse pregnancy outcomes in relation to risk categories. It was found that 97 per cent of all women had care shared by general practitioner (GP) and hospital specialist agreement. The majority (64 per cent) of antenatal visits took place away from the hospital of delivery, with GPs responsible for the largest proportion of all antenatal visits (43.5 per cent) compared with specialist hospital doctors (36 per cent) and midwives (11.5 per cent). Wide variations in the use of different personnel groups to deliver antenatal care were observed between hospitals, particularly in the use of midwives to supervise visits (4-34 per cent). The median number of antenatal visits was 14 (mean 13.9, SD 3.9). Within hospital types the differences in the mean number of antenatal visits between the three risk categories were small (one to two visits) and the direction inconsistent. In all types of hospital, outset high-risk women and those who changed to high risk were more likely to have hospital admission than those who continued as low risk. Significantly more women in the high-risk categories experienced adverse pregnancy outcomes than women who continued at low risk.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

When is "impulsiveness" not impulsive? The case of hyperactive children's cognitive style.

On two computerized versions of the Matching Familiar Figures Test (MFFT; Kagan, Child Development, 36, 609-628, 1965) pervasively hyperactive and matched control children had to identify a target from among five similar foils. One version had a temporal structure similar to the manual MFFT and trial length was determined by response speed. Hyperactive children behaved in an "impulsive" manner; they responded more quickly and made more mistakes than controls. Despite this they completed each trial more quickly than controls by identifying the target. On the second version, the length of each trial was fixed at 45 seconds. Although both groups were equally "reflective", hyperactive children still made more mistakes. Implications of these results for research in impulse control in general and hyperactivity in particular are discussed.

Attention Deficit Disorder with Hyperactivity↗
PubMed1994

A gene for pachyonychia congenita is closely linked to the keratin gene cluster on 17q12-q21.

Pachyonychia congenita (PC) is a group of hereditary syndromes which have in common a hypertrophic dystrophy of the distal nail, and are associated with a variety of additional features, notably various dyskeratoses of skin and mucous membranes. The pathology is unknown but the array of clinical features suggests the possibility of a keratin abnormality. In the present report we describe linkage analyses in a large PC pedigree of the Jackson-Lawler type, a subtype which is characterised by multiple epidermal cysts, hair abnormalities, and natal teeth. The disease locus in this family was found to be tightly linked to markers mapping within, or very close to, the keratin type I cluster at 17q12-q21; maximum lod scores for linkage of the disease to a KRT10 polymorphism and to D17S800, a marker known to be very tightly linked to KRT10, were respectively +4.51 and +7.73, both at theta = 0.00. Although always likely, our findings provide strong evidence of a keratin gene anomaly underlying an inherited disorder affecting epidermis, nail, hair, and mucosa. These findings permit testing to see if pachyonychia congenita shows any locus heterogeneity and suggest specific candidate keratin genes for mutation searching studies. In addition, they suggest a role for keratins in the phenomenon of natal dentition.

Chromosomes, Human, Pair 17↗
PubMed1994

The surface structure of Leptotrichia buccalis.

Leptotrichia buccalis shows a mosaic of surface structure on its outer membrane consisting of curved ridges 35 mm high and 22 nm apart, and erect on that surface. Fimbriae (common pili) are not present and nor is an S layer. The flap-like ridges consist of strings of macromolecules radiating from the cell surface. This ridge structure is not soluble in any of the usual chaotropes and can only be released when the outer membrane has been damaged or dispersed by extracting envelope preparations with 0.5% SDS at room temperature. The ridge is then found to be attached firmly to the peptidoglycan sacculus, which may be the point of origin of the structure. When so prepared the macromolecules forming the ridge can be removed from the sacculus by treatment with 6 M guanidine HCl, and SDS-PAGE analysis of the extract reveals a 210-kDa polypeptide as a major component and a 15-kDa minor component. The latter is probably a peptidoglycan-associated protein and much of it remains with the sacculus. Each string forming the ridge is of a volume consistent with being made of three elongated 210-kDa molecules, which are united in series by strong hydrophobic association and laterally with neighboring strings by slightly weaker forces. We confirm that L. buccalis causes haemagglutination and the bacteria are known to attach to various tissue cells. Human group A red blood corpuscles remove both of the proteins from solution, which supports the hypothesis that the ridges are adhesin structures. It is likely but not proven that the 210-kDa molecule is the adhesin.

Bacterial Adhesion↗
PubMed1994

Rapid isolation and serum-free expansion of human CD34+ cells.

Human CD34+ cells were isolated from bone marrow from normal volunteers and expanded under serum-free culture conditions. CD34+ cells were cultured with interleukin-3 (IL-3), IL-1, and stem cell factor and expanded in granulocyte-macrophage colony-forming units, erythroid blast-forming units, and CD34+ cell number during the first 7-14 days of incubation. By contrast, cultures maintained in fetal calf serum under identical conditions showed much reduced expansion, as measured by all of the above parameters. The level of expansion of the CD34+ cells was dependent on the combination of growth factors used during culture. The data establish the feasibility of serum-free expansion of progenitors and suggest the clinical use of this procedure for the generation of expanded progenitor cell products for transfusion after chemotherapy to minimize treatment-related cytopenias.

Adult↗
PubMed1994

Patient restraint: choosing the proper equipment.

In response to the Ontario Hospital Association's position paper describing the use of restraints, the Toronto Hospital responded by developing a "least restraint" policy and procedure. In the developmental stages, various types of equipment were evaluated. This paper describes the equipment selected by the safety task force and the rationale for its use.

Humans↗
PubMed1993

Characterization of a clotting protein, isolated from plasma of the freshwater crayfish Pacifastacus leniusculus.

A protein responsible for clot formation was isolated from plasma of the crayfish Pacifastacus leniusculus, by repeated precipitation at low ionic strength, pH 6.0. The protein, here named clotting protein (CP), is a lipoglycoprotein, which consists of two 210-kDa subunits, covalently associated by disulfide bonds. Preparations of the CP can form stable clots in the presence of crayfish haemocyte lysate supernatant, which contains endogenous, Ca(2+)-dependent transglutaminase (TGase) activity. The covalent, TGase-mediated polymerization of CP could clearly be visualized in SDS/PAGE under reducing conditions, where the 210-kDa subunit is covalently cross-linked into dimeric, trimeric and higher polymeric forms. The CP was shown to be a substrate for transglutaminases, since two different fluorescent TGase substrates, namely dansylcadaverine and a dansylated glutamine-containing peptide, were incorporated into the CP subunit by active TGase. This indicates the presence of both glutamine and lysine residues in the CP, accessible for TGase cross-linking. The amino acid composition and the N-terminal amino acid sequence of the clotting protein was determined.

Amino Acid Sequence↗
PubMed1993

Characterization of [3H]cytisine binding to human brain membrane preparations.

The binding characteristics of [3H]cytisine, a putative CNS nicotinic receptor ligand, were examined in 4 regions of the human brain. [3H]Cytisine was found to bind non-cooperatively with high affinity to a single site in tissue homogenates and to exhibit low non-specific association. The binding characteristics of this ligand were evaluated in thalamus at 4 degrees C and 24 degrees C. The association constants were found to be 0.234 and 0.308 min-1 nM-1, while the dissociation constants were 0.007 and 0.098 min-1, respectively. Saturation analysis of thalamus revealed the equilibrium Kd to be 147 pM (4 degrees C) and 245 pM (24 degrees C), values in good agreement with those determined kinetically. The Hill coefficient varied slightly between brain regions; however, the mean values in all regions examined were close to 1.0 at 0.95 +/- 0.03 (4 degrees C) and 0.91 +/- 0.04 (24 degrees C). [3H]Cytisine binding could be displaced using both nicotinic agonists and antagonists. Cytisine was the most potent displacer of [3H]cytisine binding with an Ki of 250 pM. Nicotine and acetylcholine were also potent displacers with Ki values of 1.8 and 8.1 nM, respectively. The nicotinic antagonists alpha-bungarotoxin and mecamylamine were ineffective competitors for the [3H]cytisine binding site while dihydro-beta-erythroidine had an Ki value of 109 nM. Thalamus showed the highest density of cytisine binding sites of all the regions examined (48 fmol/mg protein) while the hippocampus, cingulate gyrus and the cortex showed Bmax values of 18.9, 19.3 and 8.8 fmol/mg protein, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

TAP1 and TAP2 polymorphism in coeliac disease.

Coeliac disease is strongly associated with HLA-DQ2, but it is possible that additional major histocompatibility complex genes also confer disease susceptibility. Encoded close to HLA-DQ are two genes, TAP1 and TAP2, whose products are believed to transport antigenic peptides from the cytoplasm into the endoplasmic reticulum. Comparison of 81 coeliac disease patients with caucasoid controls revealed an increased frequency of the alleles TAP1A and TAP2A in the patient population. However, no significant difference was found when patients were compared with HLA-DR and -DQ matched controls, indicating linkage disequilibrium between TAP1A, TAP2A, and HLA-DQ2. The TAP gene products do not have a major influence on susceptibility or resistance to coeliac disease in a Northern European Caucasoid population.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Confirmation of the association of human papillomavirus with human colon cancer.

The human papillomavirus (HPV) has been shown to be associated with neoplasms of the human colon using immunohistochemistry and in situ hybridization. We now report our use of the polymerase chain reaction and Southern blotting to investigate that same association. We selected 38 carcinomas, 21 adenomas, and 24 normal mucosal samples for the current study. Tissue sections were prepared, and then DNA was extracted and subjected to 40 cycles of amplification using Thermus aquaticus DNA polymerase and a set of degenerate primers. Amplified products were analyzed by agarose gel electrophoresis and Southern blotting. The L1 region of the HPV genome was identified in 13 of 38 carcinomas (32%), 8 of 21 adenomas (38%), and 2 of 24 normal biopsy specimens (8%). These observations validate our previous results and confirm the presence of HPV in human colon mucosa and tumors of that mucosa.

Adenoma↗
PubMed1993

Evaluation of molecular methodologies and rabbit infectivity testing for the diagnosis of congenital syphilis and neonatal central nervous system invasion by Treponema pallidum.

IgM immunoblotting and polymerase chain reaction (PCR) were evaluated for use in diagnosing congenital syphilis, and the prevalence of central nervous system (CNS) invasion by Treponema pallidum during congenital infection was examined. The results of rabbit infectivity testing (RIT) on serum and cerebrospinal fluid (CSF) of 19 infants born to mothers with untreated early syphilis were compared with results of PCR and IgM immunoblotting. Seven infants had clinical evidence of congenital syphilis supported by positive serum IgM immunoblot (7/7), PCR (6/7), and RIT (3/3). Six symptomatic infants (86%) had T. pallidum isolated from CSF by RIT; 5 of 6 RIT-positive CSF samples were positive by PCR, and 2 also were reactive by IgM immunoblot. In 12 asymptomatic infants, 5 (42%) had a reactive serum IgM immunoblot and in 4 of these IgM reactivity was the only evidence of congenital infection. CNS invasion by T. pallidum was uncommon among asymptomatic infants; only 1 (8%) was positive by CSF RIT. The excellent agreement between RIT and PCR further substantiates the use of PCR as a surrogate for RIT. Our data indicate that the diagnosis of asymptomatically infected neonates will require a comprehensive approach using assays for both specific neonatal IgM and T. pallidum DNA in serum and CSF.

Adolescent↗
PubMed1993

Death attributed to ethyl chloride.

A young college student was found unresponsive, head down in his pillow with a metal canister containing ethyl chloride in or beside his right hand. Resuscitative efforts failed. Qualitative screening detected ethyl chloride in the vitreous fluid and antemortem and postmortem blood. Quantitation was carried out on available fluids with the following results: hospital blood, 20 mg/dL; postmortem blood, 65 mg/dL; and vitreous fluid, 41.7 mg/dL. No other drugs or volatiles were found. Death was subsequently attributed to an overdose or adverse reaction to this product.

Adult↗