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Biomedical subjects

D Foster

Publications and source records attributed to D Foster.

At least 91 records · Page 5Linked to original sources
PubMed1989

Back injuries to fast bowlers in cricket: a prospective study.

Eighty-two high performance young male fast bowlers (mean age 16.8 years) were tested immediately prior to the season for selected kinanthropometric and physiological data. Subjects were also filmed both laterally (200 Hz) and from above (100 Hz) while bowling so that their front foot impacted a force platform during the delivery stride. The players then completed a log book over the ensuing season that detailed their training and playing programmes. All cricket related injuries over this season were assessed by a sports physician who used computerized tomography to assist in the diagnosis of spinal injuries. At the completion of this season the players were grouped according to their injury status (Group 1--bony injury to a vertebra; Group 2--soft tissue injury to the back that caused the player to miss at least one game, and Group 3--no injuries). A one-way analysis of variance was used to identify if any variables were significantly (P less than 0.05) different between the three groups, and a Scheffe post hoc comparison was used to determine which groups were significantly different. Eleven per cent of the players sustained a stress fracture to a vertebra(e) (L4 to S1), while 27 per cent sustained a soft tissue injury to the back. Bowlers with a low longitudinal foot arch were more likely to develop a stress fracture than those with a high arch. Shoulder depression and horizontal flexion strength for the preferred limb and quadriceps power in the non-preferred limb were also significantly related to back injuries. Results suggest that bowlers with the above physical characteristics, who bowl with these biomechanical techniques for extended periods, are predisposed to back injuries.

Adolescent↗
PubMed1989

Phorbol ester and calcium ionophore are sufficient to promote cell replication in cultures of quiescent human B lymphocytes.

Highly purified, resting B cells could be induced to grow for up to 10 days by culturing in the presence of a synergistic combination of a tumour-promoting phorbol ester and the calcium ionophore ionomycin. In spite of evident cell death occurring, four to five times as many viable B lymphocytes could be harvested at the end of culture than were initially plated. Soluble factors derived from T cells (interleukin-2, commercial B-cell growth factor) or monocytes (interleukin-1) failed to augment further the growth-promotion observed. Evidence is presented to suggest that an autocrine component might be necessary for maintenance of the cell-cycle and growth initiated by the phorbol ester and calcium ionophore combination. The significance of these findings to B-cell physiology are discussed.

B-Lymphocytes↗
PubMed1988

The effect of polymerised fibrin on the catalytic activities of one-chain tissue-type plasminogen activator as revealed by an analogue resistant to plasmin cleavage.

A one-chain recombinant tissue-type plasminogen activator (EC 2.4.31.-) (tPA) analogue was constructed in which Arg-275 of the activation site was changed to Gly by site-directed mutagenesis. This analogue, tPA-Gly275, was very resistant to plasmin (EC 2.4.21.5) cleavage. It has been used to gain information about the activity of the uncleaved one-chain tPA form, also when plasmin is generated as a result of a plasminogen activation reaction. The amidolytic activity of tPA-Gly275 with less than Glu-Gly-Arg-pNA was investigated and compared to that of one-chain and two-chain wild-type recombinant tPA. A small but significant intrinsic amidolytic activity was observed with the analogue as well as the wild-type one-chain tPA form. However, it was much lower than that of two-chain tPA. Polymerised fibrin enhanced the amidolytic activity of both one-chain tPA forms but not of two-chain tPA. Measurements of the plasminogen activation kinetics in the absence of fibrin revealed that tPA-Gly275 possessed a significant intrinsic activity. However, it was 30-fold lower than that of two-chain tPA. Addition of polymerised fibrin profoundly enhanced the plasminogen activation rate of both tPA-Gly275 and wild-type one- and two-chain tPA to approximately the same maximal level. The results were interpreted to mean that fibrin binding can induce an activated state of the intact tPA one-chain form.

Biopolymers↗
PubMed1988

Health hazards of farming.

The U.S. farm work force numbers approximately 6.5 million. The health risks connected with their farm tasks are many and varied. Accidents and illnesses are caused by tractors, specialized farming equipment, chemicals, zoonoses, fungi, sensitizers, and the environment of confinement buildings. The scattered nature of the work force makes preventive measures difficult to implement.

Accidents, Occupational↗
PubMed1987

Selective intraarterial DSA of the parathyroid glands in patients with hyperparathyroidism after parathyroidectomy.

Eighteen patients with recurrent hyperparathyroidism after parathyroidectomy were prospectively examined with selective intraarterial digital subtraction angiography (DSA) of the brachiocephalic arteries. The results were compared with findings at reoperation. Seventeen of the 21 remaining abnormal parathyroid glands were correctly detected by selective DSA (sensitivity = 81%). In the neck and mediastinum, sensitivities were 73% (8/11) and 90% (9/10), respectively. All patients with histopathologic confirmation of primary hyperparathyroidism (17/18) became normocalcemic postoperatively. We conclude that selective intraarterial DSA is indicated in patients with recurrent hypercalcemia after parathyroidectomy when the results of noninvasive imaging techniques are uncertain.

Adolescent↗
PubMed1986

Amino acid sequence of human histidine-rich glycoprotein derived from the nucleotide sequence of its cDNA.

A lambda gt 11 library containing cDNA inserts prepared from human liver mRNA has been screened with an affinity-purified antibody to human histidine-rich glycoprotein (HRG) and then with a restriction fragment isolated from the 5' end of the largest cDNA insert obtained by antibody screening. A number of positive clones were identified and shown to code for HRG by DNA sequence analysis. A total of 2067 nucleotides were determined by sequencing 3 overlapping cDNA clones, which included 121 nucleotides of 5'-noncoding sequence, 54 nucleotides coding for a leader sequence of 18 amino acids, 1521 nucleotides coding for the mature protein of 507 amino acids, a stop codon of TAA, and 352 nucleotides of 3'-noncoding sequence followed by a poly(A) tail of 16 nucleotides. The length of the noncoding sequence of the 3' end differed in several clones, but each contained a polyadenylylation or processing sequence of AATAAA followed by a poly(A) tail. More than half of the amino acid sequence of HRG consisted of five different types of internal repeats. Within the last 3 internal repeats (type V), there were 12 tandem repetitions of a 5 amino acid segment with a consensus sequence of Gly-His-His-Pro-His. This repeated portion, referred to as a "histidine-rich region", contained 53% histidine and showed a high degree of similarity to a histidine-rich region of high molecular weight kininogen.

Amino Acid Sequence↗
PubMed1986

The heparin-binding site(s) of histidine-rich glycoprotein as suggested by sequence homology with antithrombin III.

A high degree of sequence homology has been found between the N-terminal region of histidine-rich glycoprotein (HRG) and that of antithrombin III (AT III) where the putative heparin-binding site of AT III is located. The amino acid residue at the position corresponding to Arg-47 of AT III that is essential for the heparin-binding was also arginine (Arg 23 and 78) in the homologous sequences of HRG. These observations strongly suggest that the heparin-binding sites of HRG and AT III are evolutionarily related. There was no apparent sequence similarity between the remaining about 70% portions of the two proteins.

Amino Acid Sequence↗
PubMed1986

Improvement in organically disturbed behavior with trazodone treatment.

Four elderly patients with severe organic brain syndromes and disturbed behavior were treated with trazodone after therapy with neuroleptics had been ineffective. The behavior of all four patients improved substantially. In each case, the clinical presentation did not suggest a depressive illness, and many of the disturbed behaviors, such as hypersexuality, are not generally considered characteristic of depression. The improvement in behavior may be related to the taming effect of trazodone in animal models of aggression. This effect is not shared by other antidepressants; thus, trazodone may have unique value as an alternative to neuroleptics for the treatment of organically disturbed behavior.

Aged↗
PubMed1986

Reliability of Andreasen's thought, language and communications disorder scale.

The study of disordered thinking has been hampered by a lack of clinical instruments aimed at the measurement of thought disorder. Andreasen has proposed a rating scale for thought disorder (TLC) and reported on its reliability and preliminary aspects of its validity. In our study, a psychiatrist and physician assistant rated 98 psychiatric inpatients using the TLC and BPRS. Interrater reliability ranged from 0.35 to 0.80 (weighted kappa) on 18 aspects of thought disorder and one global item. The order of reliability for the 18 individual items was strongly correlated between the Andreasen sample and our own (r = 0.77). While the BPRS thought disorder scale was significantly related to the global rating of thought disorder on the TLC (r = 0.71), only half of the variance in thought disorder measured by the TLC was accounted for by the BPRS factor. Thus, this study supports Andreasen's contention that the TLC is a reliable instrument and suggests that the instrument may provide additional information about thinking disorders.

Communication↗
PubMed1984

Characterization of a cDNA coding for human protein C.

Protein C is a precursor to a serine protease that is present in mammalian plasma. In its activated form, it readily inactivates factor Va and factor VIIIa, two proteins that participate as cofactors in the blood coagulation cascade. In the present studies, a lambda gt11 library containing cDNA inserts prepared from human liver mRNA has been screened with an antibody to human protein C. Seven positive clones were isolated from 2 X 10(6) phage and were plaque-purified. The cDNA inserts of two of these phage were sequenced and shown to code for human protein C. Each cDNA insert coded for a portion of the light chain of the molecule, a connecting region, the heavy chain, a stop codon, a 3'-noncoding region, and a poly(A) tail. The length of the noncoding sequence on the 3' end differed in the two clones, but each contained a processing or polyadenylylation signal followed by a poly(A) tail. The amino acid sequence as determined from the cDNA indicates that protein C is synthesized as a single-chain polypeptide containing the light chain and the heavy chain connected by a dipeptide of Lys-Arg. The single-chain molecule is then converted to the light and heavy chains by cleavage of two or more internal peptide bonds. In plasma, the heavy and light chains of protein C are linked together by a disulfide bond. The amino acid sequence of human protein C shows a high degree of homology with that of the bovine molecule. The DNA sequence coding for the catalytic region near the active site serine in human protein C also showed a high degree of DNA and amino acid sequence identity with prothrombin, factor IX, and factor X, three of the other vitamin K-dependent serine proteases that are present in plasma.

Amino Acid Sequence↗
PubMed1984

Male longevity and age differences between spouses.

Analysis of mortality estimates and adjusted census data showed that men aged 70 to 79 married to younger women tended to live longer than men married to older women. The standard mortality ratio for 50-year-old husbands with younger wives was 90, whereas it was 112 for husbands with older wives. For 70-year-old men the comparable values were 80 and 133. Thus the mortality risk associated with marriage to a younger woman was clearly less than that associated with marriage to an older woman. Two possible explanations were advanced for this relationship: (a) premarital selection factors may be related to longevity, and (b) psychological, physiological, or social factors associated with longevity may be enhanced by marriage to a younger woman.

Age Factors↗
PubMed1984

In vivo stimulation of low-density lipoprotein degradation by insulin.

The effect of insulin on low-density lipoprotein (LDL) metabolism in vivo was evaluated using the euglycemic insulin clamp technique. In seven subjects, mononuclear cells isolated after a 4-h insulin infusion degraded more 125I-labeled LDL than cells isolated after a saline infusion in six control subjects. In addition, insulin caused the accelerated disappearance of 125I-labeled LDL from plasma in subjects previously injected with autologous 125I-LDL. Infusion of saline had no such effect. These data suggest that insulin, in vivo, stimulates LDL catabolism and could thereby influence LDL cholesterol levels. Insulin-induced stimulation of LDL catabolism could account for the reduction of LDL-cholesterol levels observed in intensively treated type I diabetic patients.

Adult↗
PubMed1983

Kinetics of amyloid deposition. II. The effects of dimethylsulfoxide and colchicine therapy.

Amyloid (AA) protein, when deposition begins, is deposited in two stages--a rapid deposition period of 2 weeks and a plateau stage. The effect of dimethylsulfoxide (DMSO) and colchicine therapy on the kinetics of amyloid deposition was dependent on the stage of the disease at which therapy began. If given during the rapid deposition period, colchicine delayed the increase in amyloid but did not abolish it. Eventually, splenic and liver amyloid reached the level seen in untreated animals. On the other hand, DMSO given during the rapid deposition period led to significant resorption of both splenic and liver amyloid. By contrast, colchicine and DMSO given after the rapid deposition period were essentially without effect in promoting amyloid resorption. These results correlated well with the serum levels of SAA, the putative AA precursor. Colchicine given during the period of rapid AA deposition caused a transient decline in SAA levels, which eventually returned to levels seen in untreated animals. DMSO given during the rapid deposition period rapidly abolished the high SAA levels and maintained it at a level seen in normal animals. Both colchicine and DMSO therapy, if instituted after the rapid amyloid deposition period, failed to reduce SAA levels significantly below that of untreated controls.

Amyloid↗
PubMed1982

Solvent effects on ouabain binding to the (Na+,K+)-ATPase of rat brain.

The effects of the solvents deuterated water (2H2O) and dimethyl sulfoxide (Me2SO) on [3H]ouabain binding to (Na+,K+)-ATPase under different ligand conditions were examined. These solvents inhibited the type I ouabain binding to the enzyme (i.e., in the presence of Mg2+ + ATP + Na+). In contrast, both solvents stimulated type II (i.e., Mg2+ + Pi-, Mg2+-, or Mn2+-dependent) binding of the drug. The solvent effects were not due to pH changes in the reaction. However, pH did influence ouabain binding in a differential manner, depending on the ligands present. For example, changes in pH from 7.05 to 7.86 caused a drop in the rate of binding by about 15% in the presence of Mg2+ + Na+ + ATP, 75% in the Mg2+ + Pi system, and in the presence of Mn2+ an increase by 24% under similar conditions. Inhibitory or stimulatory effects of solvents were modified as various ligands, and their order of addition, were altered. Thus 2H2O inhibition of type I ouabain binding was dependent on Na+ concentration in the reaction and was reduced as Na+ was elevated. Contact of the enzyme with the Me2SO, prior to ligands for type I binding, resulted in a greater inhibition of ouabain binding than that when enzyme was exposed to Na+ + ATP first and then to Me2SO. Likewise, the stimulation of type II binding was greater when appropriate ligands acted on enzyme prior to addition of the solvent. Since Me2SO and 2H2O inhibit type I ouabain binding, it is proposed that this reaction is favored under conditions which promote loss of H2O, and E1 enzyme conformation; the stimulation of type II ouabain binding in the presence of the solvents suggests that this type of binding is favored under conditions which promote the presence of H2O at the active enzyme center and E2 enzyme conformation. This postulation of a role of H2O in modulating enzyme conformations and ouabain interaction with them is in concordance with previous observations.

Animals↗