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Biomedical subjects

J Williams

Publications and source records attributed to J Williams.

At least 829 records · Page 46Linked to original sources
PubMed1989

Comparison of nonisotopic and radioimmunoassay techniques for digoxin: a study based on external quality assurance measurements.

A comparison of the precision and accuracy of three nonisotopic and of radioimmunoassay (RIA) techniques for digoxin was made using data from 141 samples of spiked human serum assayed between 1984 and 1987 by members of the Heathcontrol external quality assurance scheme. There were significant differences between techniques in the number of observations rejected as outliers greater than 3 SD from the sample mean, the percentages of rejected measurements being Abbott TDX 1.4, RIA 3.3, Ames TDA 4.2, and Syva EMIT 6.3. Ames TDA and Syva EMIT were shown to have a significantly lower precision than the other techniques in measurements of digoxin concentrations less than 1 nmol/L. A significant 4% negative bias was observed for Ames TDA measurements of digoxin concentrations between 1 and 2.6 nmol/L. A concentration-related bias was demonstrated for Abbott TDX measurements that varied from 14% overestimates at concentrations less than 1 nmol/L to 6.7% underestimates of digoxin at concentrations greater than 2.6 nmol/L.

Digoxin↗
PubMed1989

Heterogeneity of serum creatine kinase isoenzyme MM in myocardial infarction: clinical significance and post-synthetic conversion of "abnormal" sub-bands.

We investigated the "abnormal" sub-bands of serum creatine kinase (CK; EC 2.7.3.2) isoenzyme MM in acute myocardial infarction (AMI), using isoelectric focusing in polyacrylamide gels, and compared the patterns with those for non-AMI patients and for athletes with increased CK. The "abnormal" sub-bands a (pI 7.55), b (pI 7.35), c (pI 7.25), d (pI 7.05), e (pI 6.85), f (pI 6.72), g (pI 6.50), h (pI 6.40), i (pI 6.28), j (pI 6.20), and k (pI 6.15), in common with "normal" sub-bands 1 (pI 6.91), 2 (pI 6.65), and 3 (pI 6.35), were less uniformly distributed in the AMI and demonstrated a faster rate of anodal conversion than in the non-AMI patients and athletes. "Abnormal" sub-bands a and b were detected only in the AMI patients. Incubation of myocardial CK-MM, predominantly CK-MM 1, with 2-mercaptoethanol, 15 mmol/L, resulted in conversion to the "abnormal" sub-bands b and c. Incubation of myocardial CK-MM with normal serum of low total CK yielded CK-MM 3, which on further incubation with 2-mercaptoethanol, 15 mmol/L, resulted in conversion to the "abnormal" sub-bands f and g. Comparable in vitro incubation of serum from AMI patients gave pattern changes consistent with conversion of CK-MM 1 to b, c; CK-MM 2 to d, e; and CK-MM 3 to f, g.

Adult↗
PubMed1989

Surgical glove failure rate.

Surgical gloves were collected after day-time operations for a 4-week period. Glove punctures were located by inflating each glove with compressed air and immersing the inflated glove in water. During the period of the study 681 surgical operations were performed. A total of 3790 gloves was collected, 334 gloves (8.8%) had perforations at the end of the surgical procedure. Defects occurred in one or more gloves in 32.0% of all operations.

Equipment Failure↗
PubMed1988

The production of lactate and pyruvate as sensitive indices of altered rat Sertoli cell function in vitro following the addition of various testicular toxicants.

Lactate and pyruvate are hormonally stimulated products of the Sertoli cell, which are essential for germ cell survival. The utility of measuring these products as indices of Sertoli cell function was examined using toxicants targeted to this cell type. Hence, 1,3-dinitrobenzene (1,3-DNB; 10(-6) - 10(-4) M), and mono-(2-ethylhexyl)phthalate (MEHP; 10(-8) - 10(-4) M) were tested in rat Sertoli cell cultures. Both compounds produced significant dose-related increases (maximally three- to fourfold) in lactate concentrations in the culture medium. Only 1,3-DNB produced significant dose-related increases (up to eight- to ninefold) in pyruvate concentrations. All increases occurred within 24 hr of exposure, with the earliest changes occurring within 1-2 hr. The specificity of the responses was examined by comparison with the nontoxic isomers, 1,2 and 1,4-DNB, and the parent compound of MEHP, di-(2-ethylhexyl) phthalate and its inactive metabolite, 2-ethylhexanol. None of these compounds showed significant effects on lactate or pyruvate production. The spermatocyte toxicant, ethylene glycol monomethyl ether (EGME), and its major metabolite, methoxyacetic acid (MAA), were also tested. EGME had no effect on lactate or pyruvate production, and MAA produced a decrease in lactate concentration only at the maximum dose employed (5 mM). These results show that dose-related increases in lactate production were only observed for the two Sertoli cell toxicants, and only for 1,3-DNB in the case of pyruvate production. Inactive isomers, metabolites, and germ cell toxicants did not produce these changes. Thus, lactate (and pyruvate) production by rat Sertoli cell cultures may be a sensitive index of altered function as induced by 1,3-DNB and MEHP.

Acetates↗
PubMed1988

The dimerization of half-molecule fragments of transferrin.

Partial proteolysis was used to prepare half-molecule fragments of hen ovotransferrin. N-Terminal and C-terminal fragments associate to form an N-terminal fragment-C-terminal fragment dimer. Variant forms of the N- and C-terminal fragments can be prepared in which a few amino acid residues are lacking from the C-terminal ends of the fragments. These variant fragments are partially or completely unable to associate; the suggestion that the molecular recognition sites are located in these C-terminal stretches of the N-terminal half-molecule (320-332) and of the C-terminal half-molecule (683-686) is in agreement with X-ray-crystallography data for human lactotransferrin [Anderson, Baker, Dodson, Norris, Rumball, Waters & Baker (1987) Proc. Natl. Acad. Sci. U.S.A. 84, 1769-1773].

Amino Acid Sequence↗
PubMed1988

An evaluation of two-dimensional electrophoresis for detection of human serum proteins in acute myocardial infarction.

High resolution two-dimensional electrophoresis indicates that serum proteins previously only detected in patients with acute myocardial infarction (AMI) (Gomo et al., Electrophoresis 1983, 4, 298-302) are also present in the serum protein patterns of other patients (AMI negative or demonstrating acute phase response) and are faintly detected even in controls. Thus, these proteins are not specific to AMI and are probably acute phase reactants. However, they do demonstrate a characteristic time course response in sequential samples from AMI patients.

Acute-Phase Reaction↗
PubMed1988

The sequential use of a luteinizing hormone-releasing hormone (LH-RH) agonist and human menopausal gonadotropins to stimulate folliculogenesis in patients with resistant ovaries.

The diagnostic response toward the administration of a luteinizing hormone-releasing hormone (LH-RH) analogue in the early follicular phase has been used sequentially with conventional human menopausal gonadotropin (hMG) treatment in patients who had previously failed to develop multiple follicles in response to a combination of hMG and clomiphene citrate. Nine of fourteen patients (64%) showed an increase in the number of preovulatory follicles and five subjects reached oocyte recovery for the first time. Two patients (22%) became pregnant after in vitro fertilization and embryo transfer during the treatment cycle and had healthy babies. It is suggested that this treatment regimen may be advantageous in some patients with resistant ovaries.

Adult↗
PubMed1988

Isolation and characterization of adenovirus type 12 E1 host-range mutants defective for growth in nontransformed human cells.

In order to define the functions of human adenovirus type 12 (Ad12) early region 1 (E1) products in lytic infection and oncogenic transformation we have isolated and phenotypically characterized a set of host-range (hr) mutants of this serotype. These mutants grow efficiently upon HER3 cells, which contain and express type 12 E1 genes, but are restricted for growth upon A549 carcinoma and HeLa cells. Inter- and intratypic complementation analysis, marker-rescue mapping, and DNA sequence analysis have assigned some of the mutations to E1A sequence, and some to the reading frame encoding the E1B 54-kDa (482R) protein. Phenotypic analysis of the E1B mutants in particular has revealed some interesting, and in some cases surprising, findings relating to the roles of that protein in virus-cell interactions. This Ad12 gene product is required, either directly or indirectly, for efficient viral DNA replication in A549 and HeLa cells, unlike its counterpart in type 5 virus. Surprisingly, however, despite the severe defect in viral DNA replication, the synthesis of a few species of viral late proteins continues in cells infected by some of the E1B mutants. In contrast, none of these mutants brings about the inhibition of host-cell protein synthesis characteristic of wild-type virus infection, and with some E1B mutants no viral late proteins are made. Further, in a separate study reported elsewhere, we have demonstrated that the E1B 54-kDa product may also be involved, either directly or indirectly, in positive regulation of both E1A and E1B 19-kDa (163R) gene expression. The molecular and/or physiological bases for these various effects remain to be determined, but our initial results suggest that the E1B 54-kDa protein may carry out multiple regulatory functions during the viral life cycle.

Adenoviruses, Human↗
PubMed1988

Ultrasonic wound debridement.

Current management of hand injuries includes debridement by abrasive scrubbing with anti-bacterial detergents, surgical excision, or pressure irrigation. A rat model with a contaminated laceration was used to study the efficacy of ultrasonic debridement to diminish bacterial counts and particulate matter in open wounds. Ultrasonic debridement of hand wounds has several advantages over the current methods of wound debridement. These include a technically simple procedure that is effective in the removal of particulate matter and the reduction of bacterial counts (p less than 0.005). In addition there was no blood loss and no detectable damage of viable tissues as evaluated by electron microscopy. This technique may prove to be a significant advance in the early management of hand wounds.

Animals↗
PubMed1988

The efficacy of starting postterm antenatal testing at 41 weeks as compared with 42 weeks of gestational age.

Postterm antenatal fetal surveillance has traditionally begun at 42 completed weeks of gestation. However, recent data have shown that a significant percentage of cases of perinatal asphyxia occurs between 40 and 42 weeks of gestation. We compared the perinatal outcome of fetuses with antenatal surveillance beginning at 41 weeks to those starting at 42 weeks of gestation. The study groups consisted of 908 patients who began antenatal testing at 41 weeks and 352 who began testing at 42 weeks. Antenatal testing consisted of twice-weekly amniotic fluid assessments and nonstress tests (including evaluation for late and variable decelerations). Between 41 and 42 weeks, the group whose testing started at 41 weeks had an overall incidence of intrapartum fetal distress of 2.7%, no stillbirths, and no infants with major neonatal morbidity. Patients without antenatal testing who delivered between 41 to 42 weeks did not have a significantly increased incidence of fetal distress (3.3%; p = 0.07). However, this group had a significantly increased incidence of adverse outcomes (p less than 0.05), including three stillbirths and seven cases of major neonatal morbidity. Beyond 42 weeks, the group whose testing started at 41 weeks had a 2.3% overall incidence of fetal distress. This was significantly less (p less than 0.01) than the group whose testing started at 42 weeks (5.6%). Neither of the groups had any stillbirths or infants with major neonatal morbidity. These findings suggest that starting antenatal testing at 41 weeks of gestation may result in decreased postterm perinatal mortality and morbidity as well as a decreased incidence of intrapartum fetal distress.

Female↗
PubMed1988

Evaluation of immune status in pediatric recipients of hepatic orthografts.

Survival in children following hepatic transplantation is better than in adults. We evaluated the immunologic status of both pediatric and adult patients prior to and following transplantation, to determine if there were differences in immunologic status that might contribute to this phenomenon. Studies included determination of mononuclear cell subsets, including T cells, T helper cells, T suppressor cells, and monocytes. In addition, we evaluated immune function by studying in vitro immunoglobulin (Ig) synthesis. Following transplantation, the T8 (cytotoxic/suppressor) cells in pediatric patients did not decline, whereas in adults they did (P less than .05). In vitro Ig synthesis in both adult and pediatric patients declined following transplantation. By 4 weeks, the adult group had begun to recover, whereas in the pediatric group there was still significant suppression (P less than .05). These studies suggest that there is decreased immune function in children who are recipients of hepatic allografts. Such findings could contribute to better outcome of hepatic allografting in children.

Adolescent↗