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Biomedical subjects

C Williams

Publications and source records attributed to C Williams.

At least 379 records · Page 21Linked to original sources
PubMed1994

[Malignant hyperthermia in swine: a study of atracurium in MH-susceptible swine].

Since muscle relaxants have been implicated in triggering malignant hyperthermia (MH) in MH-susceptible humans and animals, the potential of new muscle relaxants for triggering MH needs to be assessed in vivo in MH-susceptible pigs. The triggering potential of atracurium was evaluated in six MH-susceptible pigs during one hour infusion of a 90% blocking dose (0.4 mg/kg/h) of atracurium. The mean recovery time (25% to 75%) was 10.2 min and a slight increase in heart rate (142 to 170 beats per minute) was observed. Rectal temperature decreased slightly (36.4 to 35.6 degrees C) and end tidal CO2 was stable at 5.46 kpa. In this study atracurium did not trigger MH in susceptible pigs.

Animals↗
PubMed1994

Thumbsucking as related to placement and acoustic aspects of /s, z/ and lingual rest postures.

Three hundred seventy-one second graders in rural public schools were evaluated for thumbsucking, rest and swallow postures of the tongue, and articulatory placement and acoustic aspects of /s,z/. Significant relationships were observed between thumbsucking and lower dental or interdental rest and swallow postures as well as acoustic errors for /s,z/. The implications of these relationships are discussed.

Articulation Disorders↗
PubMed1993

Electronic three-dimensional imaging of intestinal endoscopy.

Endoscopists, especially those investigating the colon, need to know where the tip of the instrument is and whether the tube is kinking. A three-dimensional real-time imaging system consisting of sensors, within or taped to the endoscope, to detect weak electric currents in a wire grid below the mattress yields the information needed and should greatly facilitate performance and teaching of endoscopy.

Colonoscopes↗
PubMed1993

Estrus termination following copulation in female guinea pigs.

In the female guinea pig, estrus is inhibited after copulation. This study explored the role of the endocrine status of the male on the termination of the lordosis response in females. Ovariectomized females were treated with estradiol benzoate and progesterone to induce estrus and were then mated with males when the males were intact, castrated, and castrated and treated with testosterone propionate (TP). Lordosis responses were recorded prior to and following mating. Females who received an ejaculation from a castrated male remained sexually receptive longer than the females mated with intact males, or those males that were castrated and treated with TP. These results support the hypothesis that the factor(s) responsible for termination of estrus in females are found in the ejaculate of the male and are testosterone dependent.

Animals↗
PubMed1993

The changing pattern of infant mortality in the US: the role of prenatal factors and their obstetrical implications.

Infant mortality is one of the leading public health problems in the United States today. During the first half of this century the decline in infant mortality resulted largely from a reduction in postneonatal deaths (2-11 months after birth). Since 1950, two-thirds of all infant deaths have occurred in the neonatal period (1st month after birth). Since 1981, the rate of decline in the infant mortality rate has slowed due to a deterioration in the distribution of birthweights and a slowed improvement in birthweight-specific mortality rates. The role of birthweight is central to this issue, because low birthweight (LBW, < 2500 g) is a major determinant of death in the first year of life, particularly during the neonatal period. Stated another way, less than 0.5% of infants with birthweights > 2500 g die during the first year of life compared to 10.2% of infants with birthweights < 2500 g and 45.3% with birthweights < 1500 g (very low birthweight, VLBW). These effects are magnified when evaluated on a race-specific basis: the rate of LBW is twice as high and the rate of VLBW is three times as high for black infants compared to white infants. Reducing the rates of VLBW and LBW, particularly among blacks, holds the greatest potential for future reductions in infant mortality in the United States. The important role of maternal factors in the antecedents of infant mortality (VLBW, LBW, intrauterine growth retardation, preterm birth) have been clearly and repeatedly demonstrated. Some of these factors, such as maternal race, adverse obstetrical history and low level of education, are not amenable to change during pregnancy. Other factors, such as cessation of smoking, higher maternal weight gain and the initiation of early prenatal care have been shown to improve the course and outcome of pregnancy and subsequently result in reduced infant mortality.

Black People↗
PubMed1993

Precision in reporting the dose given in a course of radiotherapy.

A knowledge of the precise dose given in a course of radiotherapy is vital to the interpretation of the result. Despite this, an acceptable level of reporting was found in only 72 (36%) of 200 papers published in the two leading journals of radiation oncology. Analysis of the treatment data of the cases with head and neck tumours in the pilot study of CHART showed that the mean of the minimum tumour doses given was 5.1% lower than the mean of those at the intersection points. Had the same total dose been prescribed to the intersection point instead of the minimum there would have been a similar lowering of dose. There is evidence from published clinical data and a suggestion from an analysis of the CHART pilot study data that a dose difference as small as 5% may lead to real impairment or enhancement of tumour response, as well as altering the risk of morbidity. Inadequate reporting may lead to a false interpretation of a study and to its wrongful application. It is strongly recommended that it should be editorial policy to publish only those papers where the radiation dose is fully described.

Absorption↗
PubMed1993

Outpatient management of small traumatic hyphaemas: is it safe?

In this prospective study patients with small traumatic hyphaemas were managed as ambulatory outpatients. No routine systemic or topical treatment was given. The patients were reviewed daily in the Casualty Department until the blood had cleared, after which they were examined fully. The incidence of rebleeding and the number of days for the blood to clear were comparable to figures for hospitalised bed-bound patients. Nine patients (21%) defaulted from follow-up. Outpatient management of small traumatic hyphaemas is safe in compliant patients and may save valuable resources.

Adolescent↗
PubMed1993

The effects of IGF-1 treatment after hypoxic-ischemic brain injury in adult rats.

Intraventricular injection of insulin-like growth factor 1 (IGF-1) 2 h after hypoxic-ischemic injury reduces neuronal loss. To clarify the mode of action, we compared histological outcome between treatment groups in the following three studies: 0, 0.5, 5, and 50 micrograms IGF-1 given 2 h after injury; 0 and 20 micrograms IGF-1 given 1 h before; and 20 micrograms IGF-1 and insulin or vehicle alone given 2 h after. Unilateral hypoxic-ischemic injury was induced in adult rats by ligation of the right carotid and exposure to 6% O2 for 10 min. Histological outcome was evaluated in the cortex, striatum, and hippocampus 5 days later. Five to 50 micrograms IGF-1 reduced the incidence of infarction and neuronal loss in a dose-dependent manner in all regions (p < 0.05), and 50 micrograms reduced the infarction rate from 87 to 26% (p < 0.01). Pretreatment did not alter outcome. IGF-1 improved outcome compared with equimolar doses of insulin (p < 0.05) and did not affect systemic glucose concentrations or cortical temperature. The results indicate that the neuronal protective effects of IGF-1 are specific and are not mediated via insulin receptors, hypothermia, or hypoglycemic mechanisms. Centrally administered IGF-1 appears to provide worthwhile trophic support to cells within most cerebral structures after transient hypoxic-ischemic injury.

Animals↗
PubMed1993

Effect of diet on performance during recovery from intermittent sprint exercise.

Eighteen games players (9 males, 9 females) performed 30 maximum 6-sprints on a non-motorized treadmill. Each sprint was preceded by a 60-s jog at 40% maximum speed and was followed by a 54-s walk at 20% maximum speed. Thus, the entire test was of 60-min duration. The subjects were then randomly assigned to three groups and repeated the 1-h test 24 h later after consuming either a high, normal or low carbohydrate diet (79 +/- 3, 47 +/- 8, 12 +/- 1% CHO, respectively). During trial 1, mean power output declined from 653 +/- 131 to 600 +/- 158 W during the 30 sprints (P < 0.01) and power output was lower during trial 2 than during trial 1 (n = 18, P < 0.01). During trial 2, there were no differences in sprint performance between the dietary groups for the exercise test as a whole (trial 2 mean power lower than trial 1 by 0.2, 0.5 and 5.0% for the high, normal and low CHO groups, respectively; N.S.), but if only the first nine sprints are considered, then the high CHO group performed better than the low CHO group (P < 0.05). Blood lactate and glucose concentrations were lower during trial 2 than trial 1 by 4.5, 13.8 and 29.0% (lactate) and 14.9, 11.3 and 35.8% (glucose) for the high, normal and low CHO groups, respectively (both P < 0.01). Thus, both the metabolic responses to, and the performance of, maximum intermittent exercise were reduced when the test was repeated after 24 h recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Segregation of delta F508 and normal CFTR alleles in human sperm.

Single sperm typing provides an accurate method to order tightly linked loci by single cell DNA high resolution segregation analysis. We have used similar methods to type individual sperm from a known delta F508 cystic fibrosis heterozygote to determine the frequency of the mutation within his germ cell population, and to test possible explanations for the reported sex ratio distortion of the cystic fibrosis (CF) mutation to male offspring. Using a nested polymerase chain reaction we have been able to amplify a single locus sequence, cystic fibrosis transmembrane conductance regulator (CFTR), from a single target sperm haploid genome to detectable amounts without the use of radioactivity. The same sperm from a single male delta F508 carrier were simultaneously typed for the presence of the sex chromosomes to verify the ratio of X- to Y-bearing sperm and to determine the association, if any, between sex and delta F508 in male gametes. We have demonstrated that there is a significant difference in the proportions of 'normal' and 'delta F508' sperm (X2 = 7.36, p < 0.01), although when the same sperm are sexed the difference between delta F508/X and delta F508/Y sperm is not significant (X2 = 1.71, p = 0.192). Single sperm typing can address questions about segregation distortion in man, and it is unlikely that sex ratio distortion for CF carriers is due to events which occur pre-fertilisation. As these data are from one individual only, they should be confirmed for other male carriers, including those with different CF mutations.

Alleles↗
PubMed1993

Generation of neutralizing anti-B19 parvovirus human monoclonal antibodies from patients infected with human immunodeficiency virus.

The prevalence of IgG antibodies to human B19 parvovirus (anti-B19) is elevated in individuals infected with human immunodeficiency virus (HIV), especially during the later stages of HIV infection. In subjects with high titers of IgG anti-B19, 86% (19 of 22) had circulating B cells producing anti-B19. Immortalization of these cells with Epstein-Barr virus and generation of heterohybridomas by fusion with a mouse X human heteromyeloma resulted in the production of two cell lines producing IgG1 kappa monoclonal antibodies (MAbs). Both of these MAbs were specific for conformational epitopes on the VP2 capsid protein of B19 parvovirus and both were capable of neutralizing 50% of the viral infectivity in a human erythroid colony-forming unit assay at < or = 1 micrograms of MAb/mL. These human MAbs are potentially useful in the treatment of acute B19 parvovirus infection.

Antibodies, Monoclonal↗
PubMed1993

Presence of multiple forms of peptidase inhibitors in rat milk.

Peptides such as somatostatin (SS14), epidermal growth factor (EGF), transforming growth factor-alpha (TGF alpha), and insulin-like growth factors (IGF-I and IGF-II) are present in breast milk from various species, and their significance in the developing gastrointestinal tract has been suggested. Our recent studies have indicated that rat milk soluble fraction (RMSF) protects SS14 in the gastrointestinal lumen by inhibiting in vitro the luminal peptidolysis. In the present studies, we have shown that RMSF inhibited in vitro degradation by midjejunal luminal flushings of suckling rats of 125I-labeled somatostatin 14[Tyr11], EGF, TGF alpha, IGF-I and IGF-II, as well as trypsin activity in vitro against benzoyl-L-arginyl-p-nitroanilide. The inhibitory factors present in the RMSF were further fractionated by gel filtration on Sephadex G100, ion-exchange chromatography on DEAE-Sephadex, and fast protein liquid chromatography (FPLC). Gel filtration of Sephadex G100 separated RMSF into three peaks of proteins: G1, G2, and G3; peptidase inhibitor activities were present exclusively in G1. Ion-exchange chromatography on DEAE-Sephadex column resolved peptidase inhibitory activity (G1) into three different peaks, D1, D2, and D3, eluted at sodium chloride concentrations of 0.05 M, 0.1 M, and 0.2 M, respectively. Further purification of D2 by FPLC resulted in a fraction rich in peptidase inhibitory activity, which was essentially free of trypsin inhibitory activity. Results indicate the presence of at least three peptidase inhibitors in rat milk, which may play a role in the protection of milk-borne peptides in the gastrointestinal lumen.

Animals↗