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Biomedical subjects

J Miller

Publications and source records attributed to J Miller.

At least 829 records · Page 46Linked to original sources
PubMed1987

Expression of major histocompatibility complex (MHC) antigens on horse trophoblast.

Antibodies to fetal major histocompatibility complex (MHC) antigens are routinely detected in the serum of pregnant mares some 2-4 weeks after formation of the endometrial cups at Day 36-38 after ovulation. Several experimental approaches were taken to determine whether paternal MHC antigens are expressed on horse placental tissues. First, absorption of anti-paternal MHC antisera with a large volume of endometrial cup cells removed antibody activity in only 2 of 4 experiments. Second, repeated immunization of horses with endometrial cup tissue recovered from a mare on Day 47 of pregnancy failed to induce the formation of anti-MHC antibodies. Third, a potent anti-MHC antiserum, raised in a pregnant mare which had previously received skin grafts from the MHC homozygous mating stallion, labelled chorionic girdle, but not normal allantochorion, when tested in an indirect immunoperoxidase labelling assay on tissues bearing the MHC antigens of the stallion. These results indicate that the rapidly dividing cells of the chorionic girdle, the progenitor tissue of the equine endometrial cups, express high levels of paternal MHC antigen, and may serve as the alloantigenic stimulus for cytotoxic antibody production by pregnant mares. Conversely, the mature, CG-secreting endometrial cup cells have a much reduced expression of paternal MHC antigen.

Allantois↗
PubMed1987

The effect of air embolization from the femoral canal on hemodynamic parameters during hip arthroplasty.

A canine laboratory and clinical study was designed to determine the effect of air embolism during hip arthroplasty. Canine femurs were pressurized with air to 250-300 mm Hg or with low-viscosity cement to 300-900 mm Hg. Pressurization with low-viscosity cement from distal to proximal with a plugged femur revealed no change in pO2, pCO2, pulmonary artery pressure, or end-tidal CO2. Air pressurization resulted in significant increases in pCO2, pulmonary artery pressure, and end-tidal CO2, and a decrease in pO2. Pressurization of the medullary canal with xenon-labeled air was used to document pulmonary embolism. In a clinical setting, two different femoral cementing techniques during total hip arthroplasty were studied to determine their effect on hemodynamic parameters associated with embolic phenomenon. Five patients had a plugged femoral canal filled from proximal to distal with a vent tube, followed by finger-packing. Three of the patients demonstrated a significant drop in pO2 and blood pressure and a rise in pCO2 and end-tidal CO2. Five other patients had their plugged femoral canals filled from distal to proximal, three with regular cement and two with low-viscosity cement, with no significant cardiopulmonary changes. The adverse cardiopulmonary effects reported during hip arthroplasty appear to be avoided by eliminating air during the cementing procedure, by filling a plugged canal from distal to proximal.

Air Pressure↗
PubMed1987

Clinical prediction rules for computed tomographic scanning in senile dementia.

The role of computed tomography (CT) of the head in evaluating patients with dementing illnesses remains a controversial issue. Several prediction rules to guide the selective application of CT in the evaluation of dementia have recently been proposed in the medical literature. The present authors examine the value of four such rules through a validation study performed in an outpatient geriatric assessment unit. The rules were assessed in terms of their diagnostic sensitivities, specificities, misclassification rates, and information contents. Prediction rule sensitivities ranged from 12.5% to 87.5%, specificities from 37.2% to 77.9%, and misclassification rates from 23.5% to 60.8%. Of the four prediction rules examined, one emerged as significantly more sensitive than the others, and also served to reduce diagnostic uncertainty a full order of magnitude more than the others, as determined by an information content analysis. Disadvantages to this rule, however, were found in its more complex nature and the assessment of a very high rate of misclassification. Through a critique of existing strategies, this study purports to determine the potential for establishing a useful clinical prediction rule to guide selective CT scanning in the diagnostic evaluation of dementia.

Aged↗
PubMed1986

Efficient cell surface expression of class II MHC molecules in the absence of associated invariant chain.

The intracytoplasmic forms of class II (or Ia) major histocompatibility complex heterodimers are associated with a third glycoprotein, termed the invariant chain (Ii). This specific interaction has led to the view that Ii plays a necessary role in the assembly, intracellular transport, and/or membrane insertion of Ia molecules. To test this hypothesis directly, we have transfected complementary DNA clones that encode murine class II alpha and beta chains into cells that do not express any endogenous Ii messenger RNA (mRNA) (COS-7 and BALB/c 3T3 cells). After DNA-mediated gene transfer, significant cell surface expression of Ia was observed in transient expression assays using COS-7 cells and a stable expression system using BALB/c 3T3 cells. Furthermore, the total levels of class II alpha and beta mRNA were similar in Ii- cells (transfected BALB/c 3T3) and in Ii+ cells (B cell hybridoma) that expressed nearly identical amounts of surface Ia, suggesting that the efficiency of Ia expression was equivalent in the two cell types and, therefore, independent of Ii. These results indicate that the physiologic role for Ii is not simply to mediate membrane expression of Ia molecules, and that alternative hypotheses concerning the true function of this molecule need to be considered.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1986

The influence of stimulus parameters on the potentiation of striatal dopamine release by metoclopramide: in vivo voltammetric data.

Carbon fibre microelectrodes were implanted acutely into the striatum of chloral hydrate-anaesthetised rats to measure the dopamine released by electrical stimulation of the ipsilateral nigrostriatal pathway. High speed cyclic voltammetry was used throughout. The effects of metoclopramide and of different stimulation parameters (frequency and duration) were investigated. Using a 10 s stimulus train, it was found that frequencies less than 25 Hz evoked little measurable dopamine release. Maximum release occurred at 50-62.5 Hz. Metoclopramide (2.5-20 mg/kg i.p.) increased stimulated dopamine release in a dose-dependent fashion. The effect of metoclopramide (10 mg/kg) was investigated in detail at 25, 37.5 and 50 Hz stimulation frequency and at 2.5, 5.0 and 10.0 s after the onset of stimulation. Metoclopramide, at all stimulation frequencies, caused the largest percentage elevation of release at 2.5 s of stimulation. The results indicate that prolonged stimulation can deplete the releasable pool of dopamine and mask the effects of dopamine receptor blockade.

Animals↗
PubMed1986

Hepatitis A infection in New Zealand children.

Antibody to hepatitis A virus (anti HAV), a marker of past infection, was assayed in 2000 sera collected as part of a national survey in 1978-79. The sera were obtained from children and young people aged 0-21 years, resident in all health districts of New Zealand. Anti HAV was detected in 307 sera, giving an overall prevalence of 15.4%. Prevalence increased steadily throughout childhood but more slowly during adolescence. There was no sex differential, the age-standardised rate/100 being 15.5 (95% confidence interval 13.2, 17.8) for males and 16.6 (14.4, 18.9) for females. However, the age-standardised rate for Maoris was 39.5 (33.2, 45.8) compared to 16.1 (12.8, 19.4) for Europeans, giving a risk ratio of 2.1. In addition, a marked north-south gradient in prevalence was demonstrated: the rate for children in the northern half of the North Island, when standardised for age and ethnicity, was 19.8 (16.8, 22.7) compared to 5.2 (3.2, 7.1) for South Island children, giving a risk ratio of 3.8. The higher prevalence of hepatitis A infection in Maori and northern North Island children mirrors our previously reported findings regarding markers of hepatitis B infection in this serum collection.

Adolescent↗
PubMed1986

Isolation and characterization of a 30 kDa membrane glycoprotein from human stratum corneum.

Using iodinated concanavalin A in conjunction with gel electrophoresis, we have identified a 30 kDa glycoprotein in the stratum corneum of human skin. We isolated this glycoprotein by extraction in nonionic detergent, affinity chromatography and preparative gel electrophoresis. It binds to concanavalin A but not to three other lectins. The purified glycoprotein migrates at 30 kDa whether or not reducing agents are present. It is rich in histidine and lysine, but lacks arginine, proline, tyrosine and methionine. It is clearly distinct from filaggrin. We prepared a monospecific polyclonal antibody to this glycoprotein and localized it by immunohistochemistry exclusively to the cell membrane of corneocytes. We postulate that the glycoprotein may play a role in the cohesion and desquamation of corneocytes.

Adult↗
PubMed1986

Structure and analysis of the bovine atrial natriuretic peptide precursor gene.

The isolation and sequence analysis of the gene encoding the bovine atrial natriuretic peptide (ANP) precursor is described. The bovine-ANP coding sequences are located on three exons which are interrupted by two intervening sequences. Comparison of the bovine, human, rat and mouse ANP gene sequences reveals a common organization of introns and exons and a high degree of sequence homology in the 5'-flanking and coding regions. Examination of the pre-proANP amino acid sequence derived from the bovine gene with those from rat, mouse and human, indicates a high degree of sequence homology in both the amino-terminal and biologically-active carboxy-terminal ANP region. The latter region in the bovine sequence resembles its human counterpart except for a carboxy-terminal Arg-Arg dipeptide.

Amino Acid Sequence↗
PubMed1986

Characteristic craniofacial appearance and brachytelephalangy in a mother and son with Kallman syndrome in the son.

We report on a mother and son with a similar facies characterized by a square forehead, small nose, telecanthus, and thin upper lip. They both had a similar metacarpal-phalangeal profile characterized by marked brachytelephalangy. They were both short in comparison to other family members, and the son had hypogonadotropic-hypogonadism and anosmia. We favor the hypothesis of a single autosomal dominant gene with variable expression of the hypogonadism and anosmia, although there are alternative explanations for the combination.

Adolescent↗
PubMed1986

Response of malignant and nonmalignant epidermal cell lines to tunicamycin.

Exposure of fibroblasts to tunicamycin has been found to be cytotoxic for transformed cells, but not for nontransformed cells. With two mouse epidermal cell lines of common origin, we observe a contrary pattern: The malignant cells are more resistant to tunicamycin than their nonmalignant counterparts, as measured by growth and viability. With respect to the glycosylation of sugar precursors, the incorporation of mannose is more inhibited than that of glucosamine, while fucose is least impacted. Sugar incorporation is less reduced for the malignant cells, by a factor of two for fucose and more modestly for the other two sugars. There are no significant morphological changes; in particular, the desmosomal junctions are not affected. On polyacrylamide gels, we note intensity variations in several protein bands in response to tunicamycin, but little difference between malignant and nonmalignant cells when using either Coomassie stains or Concanavalin A overlays.

Animals↗
PubMed1986

Canine resistances to gastric emptying of liquid nutrients after ulcer surgery.

In two groups of dogs, we studied average rates of gastric emptying of 0.15 M NaCl, 0.6 M glucose, or 0.04 M oleate liquid meals while gastric pressures were controlled by a barostat and compared this emptying to spontaneous gastric emptying of the same three meals. In the first group of dogs, this comparison was made before and after truncal vagotomy + pyloroplasty (TVP); and in the second group, before and after antrectomy, first with gastroduodenostomy (A-BI) and then with Roux-Y bypass (A-RY). Under barostatically controlled gastric pressures, gastric emptying of oleate and glucose remained slower than emptying of saline before as well as after TVP or A-BI and A-RY. However, all operations accelerated initial spontaneous emptying, compressing differences between half-emptying times of the three meals. We conclude postfundic resistances remain after TVP or antrectomy but may act too late to alter rapid initial emptying.

Animals↗
PubMed1986

Nucleotide and deduced amino acid sequence of the influenza neuraminidase genes of two equine serotypes.

Equine influenza is caused by two serotypes of type A influenza virus, EIV-A1 and EIV-A2. The complete nucleotide sequence of the neuraminidase (NA) genes of both the A1 (N7 subtype) and A2 (N8 subtype) serotype has been determined following cloning of full-length viral NA cDNAs into pBR322. Analysis of the deduced amino acid sequences reveals that the N7 and N8 genes share expected extensive homologies with the previously sequenced N1, N2, and N9 NA subtypes. These homologies include conservation of basic NA gene and protein structure, cysteine residues, potential glycosylation sites, and residues known to reside in the enzyme active site of the NA molecule. Additionally, the N1 and N8 molecules and the N7 and N9 molecules are more related by total amino acid homology than any other combination of two subtypes. The area of homology in both cases is particularly strong in the region of residues 100-205, an area roughly corresponding to the amino terminal one-third of the "head" of the NA protein.

Amino Acid Sequence↗
PubMed1986

Renal toxicity of propyleneimine: assessment by non-invasive techniques in the rat.

The nephrotoxicity of three different dose levels of propyleneimine (10, 20 and 30 microliter/kg body wt) administered intraperitoneally to rats was studied and 20 microliters/kg body weight was found to be the most appropriate sublethal dose. Injection of propyleneimine (10 microliters/kg body wt) produced a small rise in N-acetyl-beta-D-glucosaminidase (NAG) activity, minor histological damage but no change in urine volume. Six rats were injected with 20 microliters/kg body weight, and urine was collected over the following 16 days. An immediate increase in urine volume, osmolality together with a concomitant decrease in specific gravity, was accompanied by a small increase in creatinine excretion and a more marked increase in the sodium and potassium content of urine after the administration of the nephrotoxin. NAG activity increased immediately and peaked on day 3, the activity remained elevated until day 12 when it fell to near normal levels. The activity of both beta-D-galactosidase and beta-D-glucosidase increased 9 days after administration of the nephrotoxin. In contrast, no consistent change was found in the excretion of the brush border marker enzymes, leucine aminopeptidase (LAP), alanine aminopeptidase (AAP) or alkaline phosphatase (ALP). Proteinuria increased sharply the day after injection and remained abnormal. Increased urinary albumin excretion and the predominance of low molecular weight proteins was demonstrated by sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis. Evidence is presented that propyleneimine exerts its early toxic effect on the renal papilla.

Acetylglucosaminidase↗