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Biomedical subjects

A Smith

Publications and source records attributed to A Smith.

At least 973 records · Page 54Linked to original sources
PubMed1989

The effect of loading on position sense at the proximal interphalangeal joint of the human index finger.

1. Proprioceptive acuity was tested at the proximal interphalangeal joint of the index finger of normal subjects. 2. Examination of the ability of the subjects to match finger positions (position matching procedure) revealed that digital nerve block (DNB) of the finger resulted in characteristic alignment errors at the extremes in all subjects. 3. When one finger (target finger) is positioned close to full extension, all subjects hyperextended the anaesthetized matching finger, whilst target finger positioning towards full flexion resulted in hyperflexion of the matching finger. At intermediate positions the pattern of matching errors was more variable but tended to be consistent for a given subject. 4. When the matching finger was isotonically loaded into flexion, there was little change in matching performance for most subjects. However, when the matching finger was anaesthetized, such loading now produced clear alteration in performance in all subjects. This indicates that muscle receptors contribute to proprioceptive sensations at this joint, but require other afferent sources to optimally resolve position when the finger is loaded. 5. Two other test procedures (angle reproduction and assigned positions) were assessed and compared with the results obtained by the position matching technique. Although alterations in proprioceptive performance during DNB could be detected with these procedures, they tended to be less sensitive than the position matching procedure.

Adult↗
PubMed1989

Impaired delayed type cutaneous hypersensitivity in rheumatoid arthritis reversed by chrysotherapy.

A prospective 24 week study of 31 patients with active rheumatoid arthritis (18 women, 13 men) was undertaken to determine whether weekly intramuscular sodium aurothiomalate (gold) would influence delayed type cutaneous hypersensitivity (DTH) and other indices of cell mediated immunity. DTH to seven recall antigens was measured by Multitest on three occasions during the study. Twenty five patients completed the study. At entry 13 patients (12 female) were anergic, and no significant correlations were found between DTH and other clinical and immunological indices. Women showed a significantly greater depression of DTH than men. At week 24 only three of the patients were anergic with significant increase in mean DTH score being noted particularly to tuberculin, candida, and streptococcus. Improvement in DTH was observed in both gold responders and non-responders. In conclusion, patients with active rheumatoid arthritis show impairment of DTH, which is reversed by chrysotherapy. This effect is most apparent in women and appears to be relatively independent of the clinical response.

Adult↗
PubMed1989

Blepharophimosis plus ovarian failure: a likely candidate for a contiguous gene syndrome.

We describe four females from three families with blepharophimosis, epicanthus inversus, and ptosis who were found to have premature ovarian failure. In two families the inheritance was autosomal dominant and in one it was a new mutation. Two females had, in addition, dysmorphic facial features which have been described in other cases. We suggest that the aetiology of the blepharophimosis ovarian failure syndrome is a contiguous gene syndrome.

Adult↗
PubMed1989

Sigje, a member of the small inducible gene family that includes platelet factor 4 and melanoma growth stimulatory activity, is on mouse chromosome 11.

Stiles and coworkers originally identified a gene they termed JE that is transcriptionally activated in mouse fibroblasts early after treatment with platelet derived growth factor or serum. This gene, now named Sigje, can encode a 148-amino acid secreted, basic polypeptide that belongs to the small inducible gene (SIG) family whose members include, for example, platelet factor 4, melanoma growth stimulatory activity (Mgsa), and interferon inducible protein 10. SIG family members share a conserved array of cysteine and proline residues and a similar predicted secondary structure, and may have evolved from a common ancestral gene. Several members of the SIG family have been assigned to the proximal long arm of human chromosome 4, to a region that has genetic homoeology with a portion of mouse Chromosome 5. We report here that mouse Sigje, in contrast to Mgsa, is on Chromosome 11. Sigje restriction fragment length polymorphisms in Mus spretus DNA were identified with the enzymes TaqI, MspI, BclI, and XbaI, and will be useful in mapping by meiotic recombination.

Animals↗
PubMed1989

Progress in purification of virus-inactivated factor VIII concentrates. Three generations of solvent/detergent treated plasma derivatives.

A production process of a newly developed highly purified and virus-inactivated Factor (F) VIII-concentrate (Octa V.I. and Octavi) is presented. Taking advantage of a selective resin matrix and the solvent/detergent procedure for virus inactivation--known not to denaturate proteins--a product of a specific activity greater than or equal to 100 IU F VIII/mg could be developed in the final container without the use of an immuno-affinity adsorption step. The main steps of the procedure are: Pooled cryoprecipitate is extracted, the extract is cleared from fibrinogen at + 10 degrees C and virus-inactivated at + 28 degrees C after addition of tributyl-phosphate (TNBP) and detergent. Thereafter the extract is brought in contact to a F VIII-selective anion exchange resin using a chromatographic column. TnBP and the detergent are removed by an extensive washing process and the F VIII-activity is concentrated in a fraction, ready for filling, by means of a cascade of wahing- and elution-buffers. The product is free from coagulable protein and gamma-globulins. The F VIIIC: Ag/F VIII:C-ratio is about unity, suggesting the F VIII-molecule remained in its native state. The development of highly purified F VIII concentrate is based on two previous products of lesser purity (spec. activity of about 1 and 10 IU/mg). The evolution is shown by a comparison of detailed analytical data.

Chromatography, Ion Exchange↗
PubMed1989

Anomalous origin of the left coronary artery from the pulmonary trunk. Anatomic findings in relation to pathophysiology and surgical repair.

Anomalous origin of the left coronary artery from the pulmonary trunk, though a discrete anatomic malformation, manifests a spectrum of clinical and pathologic consequences. The objectives of this study were to characterize the primary anatomic findings in a group of specimens with anomalous left coronary artery and the extent of secondary morphologic and pathologic changes. Although the cases studied probably represent the least favorable end of the spectrum, the observed pathogenesis and evolution of secondary changes suggest that reconstruction of a two-coronary arterial system supplied through two coronary arteries would be advantageous to most patients. A high origin of the right coronary artery or location of the left coronary artery adjacent to a pulmonary cusp or branch may complicate the tunnel-type repair. In these cases, transfer of the left coronary artery to the aorta may be preferable.

Abnormalities, Multiple↗
PubMed1989

Identification of clinically significant skeletal muscle necrosis by single photon emission computed tomography.

Ischemia-reperfusion damage to skeletal muscle may cause serious local as well as systemic complications, its impact predominantly related to the quantity of ischemic muscle in the lower extremity. To date, there has been no noninvasive method of estimating that quantity. The authors used single photon emission computed tomography (SPECT) to quantify the volume of muscle that takes up technetium-99 pyrophosphate above a baseline threshold. Compared with the standard technique of staining slices of the muscle with nitroblue tetrazolium they found a close correlation using SPECT (r = 0.88, p less than 0.01, n = 19) in the canine model. In humans, this clinically applicable noninvasive technique may allow the surgeon to document accurately the extent of muscle necrosis in the lower extremity, to anticipate the impact of an ischemia-reperfusion injury and evaluate methods of reducing the extent of post-ischemic skeletal muscle necrosis.

Animals↗
PubMed1989

Candidiasis-endocrinopathy syndrome with progressive myopathy.

A women suffering from the candidiasis-endocrinopathy syndrome, developed severe myopathy in her fourth decade and died from it at the age of 37 years. Associated conditions were hypoparathyroidism, vitiligo, chronic mucocutaneous candidiasis, short stature, intellectual disability, ovarian failure and alopecia totalis. Muscle biopsy findings were non-specific with focal atrophy of type 2 fibres. Serum immunoglobulin levels were normal. The only demonstrable abnormalities of her immune system were impaired T-cell function and antibody production by B-cells (detectable to smooth muscle, mitochondria and gastric parietal cells). The T-cell abnormality may have been part of a more generalized cell defect, resulting from an unidentified genetic abnormality, whilst the circulating antibodies could have been a response to tissue damage. There was no convincing evidence of primary autoimmune damage.

Adult↗
PubMed1989

The medial papillary muscle complex and its related septomarginal trabeculation. A normal anatomical study on human hearts.

The morphology of the medial papillary muscle complex of the right ventricle was studied in 81 normal hearts from subjects ranging in age from 20 weeks of gestation to 13 months. The position of the main medial papillary muscle (of Lancisi) was differentiated in terms of a root and a belly. The anterior aspect of the root was found in a constant position at the basal bifurcation of the septomarginal trabeculation, whereas its belly showed considerable positional variation. Three groups of minor papillary muscles were identified and localised in specific areas in the base of the right ventricle. Taken overall, they formed part of the medial papillary complex. The complex itself was found to be constantly related to the antero-septal commissure of the tricuspid valve. A separate group of septal papillary muscles could be differentiated from the medial papillary complex. The anchorage of the septal leaflet of the tricuspid valve to the ventricular septum was also studied. The antero-superior and postero-inferior portions of this leaflet were found to be supported by the medial and posterior papillary complexes, respectively. Its midportion was connected to the septal group of papillary muscles but much variability was evident. The portion of the septomarginal trabeculation supporting the medial papillary complex, namely the postero-basal division, was studied further. This showed considerable variability and did not form a continuous anatomical spectrum.

Fetus↗
PubMed1989

Post-mortem studies on two patients with 1-2 band cytogenetic deletions: 10q26----qter and r(9)(p24q34).

Two severely retarded males with unbalanced karyotypes Case 1--(45,XY,--10,--15, + der(10)t,(10; 15) (q26; q13) and Case 2--46,XY,r(9) (p24q34) died at the ages of 24 and 38 years respectively. At post-mortem, a post-ductal coarctation of the aorta and a lump kidney were found in the first case. Brain pathology was normal in the first case and apart from a smaller size, was structurally normal in the second case.

Adult↗
PubMed1989

Classical Prader-Willi syndrome with trisomy 15(pter----q12) plus de novo variant 15p11.

We describe a boy with the classical Prader Willi syndrome (PWS), clinically, who had a chromosome abnormality not previously described in PWS. The karyotype was 47,XY,+mar, var(15)(p11). The marker was a fragment of 15 from 15pter----q12 and the variant 15p11 was de novo in origin. Overall, this karyotype contains increased 15 heterochromatin and we discuss alteration in the amount of 15 heterochromatin in PWS.

Chromosomes, Human, Pair 15↗
PubMed1988

Antioxidant protection by haemopexin of haem-stimulated lipid peroxidation.

Haem (ferrous protoporphyrin IX) is a reactive low-molecular-mass form of iron able to participate in oxygen-radical reactions that can lead to the degradation of proteins, lipids, carbohydrates and DNA. Oxygen-radical reactions are likely to occur upon tissue damage. Extracellular fluids rely on antioxidant mechanisms different from those found inside the cell, and circulating proteins limit radical reactions by converting pro-oxidant forms of iron into less-reactive forms. Of the compounds tested, only apohaemopexin and the chain-breaking antioxidant butylated hydroxytoluene inhibited (by more than 90%) haemin-stimulated peroxidation as measured by formation of conjugated dienes, thiobarbituric acid-reactive material from linolenic acid or peroxidation-induced phospholipid fluorescence. Haptoglobin, the haemoglobin-binding serum protein, was ineffective. Conversely, only haptoglobin significantly inhibited haemoglobin-stimulated lipid peroxidation. Iron-salt-induced lipid peroxidation was inhibited only by apotransferrin and the iron-chelator desferrioxamine. All lipid peroxidations were inhibited by the radical scavengers butylated hydroxytoluene and propyl gallate. These findings support the concept that transport and conservation of body iron stores are closely linked to antioxidant protection.

Antioxidants↗
PubMed1988

Expression of the haemopexin-transport system in cultured mouse hepatoma cells. Links between haemopexin and iron metabolism.

Minimal deviation hepatoma (Hepa) cells, from the mouse hepatoma B7756, synthesize and secrete haemopexin and express both the haemopexin receptor and the membrane haem-binding protein (MHBP) associated with the receptor, making this cell line the first available for detailed study of both haemopexin metabolism and hepatic transport. The 17.5 kDa MHBP was detected in Triton X-100 extracts of Hepa cells by immunoblotting with goat anti-rabbit MHBP. Scatchard-type analysis of haem-125I-haemopexin binding at 4 degrees C revealed 35,000 receptors per cell of high affinity (Kd 17 nM). Haemopexin-mediated haem transport at 37 degrees C is saturable, having an apparent Km of 160 nM and a Vmax. of 7.5 pmol of haem/10(6) cells per h during exponential growth. Haem-transport capacity is highest in the period just before the cells enter their exponential phase of growth and slowest in stationary phase. Interestingly, haem-haemopexin serves as effectively as iron-transferrin as the sole source of iron for cell growth by Hepa cells. Furthermore, depriving Hepa cells of iron by treatment with desferrioxamine (DF) increases the number of cell-surface haemopexin receptors to 65,000 per cell and consequently increases haemopexin-mediated haem transport. The effects of DF do not appear to require protein synthesis since they are not prevented by cycloheximide. Treatment of Hepa cells with hydroxyurea, an inhibitor of the iron-requiring enzyme ribonucleotide reductase that is obligatory for DNA synthesis, enhanced haemopexin-mediated haem transport. Thus, these studies provide the first evidence for regulation of haem transport by the iron status of cells and suggest a linkage between haemopexin, iron homeostasis and cell growth.

Animals↗
PubMed1988

Gene conversion and differential regulation in the rat P-450 IIA gene subfamily. Purification, catalytic activity, cDNA and deduced amino acid sequence, and regulation of an adult male-specific hepatic testosterone 15 alpha-hydroxylase.

Previous studies on regulation of the rat hepatic P-450 IIA1 cDNA have provided evidence for a second gene closely related to but regulated in a manner quite distinct from P-450 IIA1. Experiments were carried out to isolate the cDNA for this second P-450 gene, designated IIA2, in order to study more directly its regulation and relationship to IIA1. A full length cDNA to IIA2 was isolated from an adult male rat liver lambda gt11 library and sequenced completely. The IIA2 cDNA shared 93% nucleotide and 88% deduced amino acid similarities with the previously characterized IIA1 cDNA (Nagata, K., Matsunaga, T., Gillette, J., Gelboin, H. V., and Gonzalez, F. J. (1987) J. Biol. Chem. 262, 2787-2793). The protein, deduced from the cDNA, contained 492 amino acids and a calculated Mr of 56,352. Comparison of the IIA1 and IIA2 cDNAs revealed areas of low nucleotide similarity interspersed with areas of absolute identity, suggesting that gene conversions have played a role in the evolution of the IIA subfamily. Expression of IIA1 and IIA2 mRNAs in rat liver during development was studied with use of specific oligonucleotide probes. IIA1 mRNA was increased within 1 week after birth in both male and female rats; however, its postpubertal expression was decreased in males yet remained elevated in females. In contrast, IIA2 mRNA was markedly induced in male rat liver at puberty but was not detectable in females at any age examined. Furthermore, only IIA1 mRNA was induced by treatment of rats with 3-methylcholanthrene. Although IIA1 and IIA2 mRNAs were actively expressed in hepatic tissue, no evidence for their expression was found in lung, kidney, or intestine, suggesting that the IIA genes have tissue-specific promoters. Reconstituted enzyme assays on the purified protein products P-450 IIA1 and P-450 IIA2 showed that, although both enzymes share considerable sequence similarity, their positional specificities toward the prototype substrate testosterone are strikingly different.

Amino Acid Sequence↗