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Biomedical subjects

S G Williams

Publications and source records attributed to S G Williams.

At least 91 records · Page 5Linked to original sources
PubMed1984

MMPI results: a comparison of trauma victims, psychogenic pain, and patients with organic disease.

Made comparison using MMPI T scores on three private psychiatric sub-populations: Post-trauma patients, patients with organically based illness, and patients with psychogenic pain (complaints functional in origin) (N = 78). The standard 3 validity and 10 clinical scales were used to evaluate possible differences among the groups. Differences were presented among the groups on scales 3 (Hy), 9 (Ma), and (F). Individual profiles also were assessed. In patients with a 1-3/3-1 profile, the psychogenic group had significantly higher elevation over the post-trauma and organic groups. In patients with 8 (Sc) or 9 (Ma) high both with and without 1-3/3-1 high, differences were found; the post-trauma and organic groups showed marked elevation over those in the psychogenic group. Results indicate the MMPI to be a viable aid in distinguishing between patients with post-trauma stress disorder vs. those with functional disorders. The data suggest that MMPI profiles of patients with post-trauma stress disorder more closely resemble the MMPI profiles of patients who have organic disease with pain caused by organic pathology than the profiles of patients with psychogenic pain and/or hypochondriasis.

Adult↗
PubMed1983

Pharmacokinetics, pharmacodynamics and dose-response relationships of atracurium administered i.v.

A complete pharmacokinetic and pharmacodynamic model for the novel non-depolarizing neuromuscular blocking agent atracurium is proposed, which accounts for tetanic and single twitch responses after any i.v. administration of this drug. The means and standard deviations of the kinetic parameters are given from studies in 19 patients, and the pharmacodynamic parameters from eight patients in whom plasma drug concentrations and dynamic responses were recorded concurrently. Similarities in dynamic parameters are noted for atracurium administered to cats, and for other non-depolarizing neuromuscular blocking agents in man. The use of this approach allows clinicians to understand and rationalize all the features associated with the time-course of blockade after varied i.v. regimens, but more importantly, allows them to design any required neuromuscular blocking profile which will also result in minimal drug loading of their patients.

Atracurium↗
PubMed1982

Cigarette smoking, manifest anxiety and somatic symptoms.

Fifty smokers and fifty non-smokers were administered the MMPI's Manifest Anxiety Scale (MAS). Mean MAS scores for smokers were significantly higher than those of non-smokers. Item analysis revealed that smokers obtained higher scores than non-smokers on significantly more items in which anxiety is manifested by a physical symptom rather than a psychological symptom. It is possible that physical stimulation by nicotine may contribute to a more ready arousal to anxiety in smokers.

Adult↗
PubMed1978

Surveillance of gentamicin-resistant gram-negative bacilli in a general hospital.

Aerobic gram-negative bacilli isolated from clinical specimens from 1 January to 31 December 1976 were tested for gentamicin and tobramycin resistance by standardized disk testing. For Pseudomonas isolates, gentamicin resistance was 17.1% and tobramycin resistance was 2.8%. For other gram-negative bacilli, gentamicin resistance was 5.5% and tobramycin resistance was 5.4%. Seventy-four patients from whom gentamicin-resistant organisms were isolated from 1 January to 30 June 1976 were studied prospectively. These patients were elderly, had serious underlying diseases, and had received prior antibiotic therapy. Eleven patients carried gentamicin-resistant organisms at the time of transfer to our hospital from community hospitals or nursing homes. Of the 82 isolates from these 74 patients, 52 were from the urine. Pseudomonas was found most frequently (32 isolates), followed by Klebsiella (15 isolates), Enterobacter (10 isolates), Serratia (10 isolates), and Proteus (9 isolates). Only 3 of 32 Pseudomonas isolates caused symptomatic infection, while 16 of 50 other gram-negative bacilli were responsible for symptomatic infection. Although amikacin was the most active drug against gentamicin-resistant gram-negative bacilli and had not been used in our hospital at the time of this study, 25% of Pseudomonas and 18% of all gram-negative bacilli showed resistance to this aminoglycoside.

Aged↗
PubMed1978

Survival of Streptococcus pneumoniae in sputum from patients with pneumonia.

The isolation rate of Streptococcus pneumoniae in sputum cultures from patients with pneumococcal pneumonia is low. An investigation was made to determine whether this low yield might be due to loss of pneumocci and/or overgrowth by pharyngeal flora before the specimen is plated. Pneumococcal survival times and pharyngeal overgrowth at 4 degrees C and at room temperature were determined in sputum obtained from 42 patients with pneumococcal pneumonia. It was found that pneumococci survived for long periods in sputum--2.2 +/- 1.4 days at room temperature and 9.5 +/- 3.6 days at 4 degrees C. Overgrowth by pharyngeal flora occurred in only 6 of 42 specimens kept at 4 degrees C and 31 of 42 specimens kept at room temperature. The low yield of S. pneumoniae in sputum from patients with pneumococcal pneumonia is not explained by decreased viability of the organism.

Adult↗
PubMed1975

Physiochemical-activity relations in practice. 1. A rational and self-consistent data bank.

A data bank of substituent constants of 26 ortho and 34 meta and para benzenoid substituents is presented for use in physicochemical-activity relations (PAR) studies. The distributive parameters pri and pri-, a bulk parameter based on molar refraction, and positionally weighted electronic parameters F and R are listed for the three substituent positions. There are no gaps in the table caused by missing values and the interparameter correlation are low.

Chemical Phenomena↗
PubMed1975

Forecasting the antimalarial activities of arylamidinoureas from their measured physicochemical properties.

1 The octanol : water partition coefficient (PC), protein binding coefficients to albumin (Ba) and haemoglobin (Bh), proton magnetic resonance (PMR) chemical shifts and pKa of 8 arylamidinoureas have been measured. 2 There were statistically significant correlations for 7 of the 8 compounds between the predicted lipophilicity parameter eta and log PC, Ba and Bh, and also between Hammett's electronic parameter sigma and the PMR and pKa observations. 3 3-Chloro,4-nitrophenylamidinourea showed a larger deviation from these correlations than any other compound. Geometric calculations based on the covalent radii and bond angles of the molecule suggested that the neighbouring chloro and nitro substituents were interacting sterically. 4 Molecular orbital calculations and the observed ultra-violet spectrum provided further evidence for such an interaction, and suggested that the nitro group is twisted out of the plane of the benzene ring in this molecule. 5 Such steric interactions can introduce an additional source of error when attempts are made to correlate the biological and predicted physicochemical properties of compounds. 6 Generalized parameters such as eta and sigma cannot be used with confidence to predict the properties of compounds in which such steric interactions occur.

Amidines↗
PubMed1975

Malaria studies in vitro. IV: Chloroquine resistance and the intracellular pH of erythrocytes parasitised with Plasmodium berghei.

The erythrocytic stages of strains of plasmodia sensitive to chloroquine (CQ) concentrate some three to six times more drug than CQ-resistant strains. A simple, but so far untested hypothesis is that the intracellular pH of drug resistant strains is higher than that for sensitive strains. This would result in a reduced accumulation of any weakly basic drug molecule (e.g. CQ) which is capable of passive diffusion through the cellular membran. The mean intracellular pH of erythrocytes parasitised with either CQ-sensitive or CQ-resistant strains of P. berghei was determined, therefore, from the distribution of 14C-5, 5-dimethyloxazolidine-2,4-dione between intra- and extracellular aqueous phases. The results obtained showed that over the range 6-8--7-2 the intracellular pH is governed directly by the extracellular pH and that the intracellular pH of CQ-sensitive parasites is slightly above that for resistant ones, neither being greatly different from that for uninfected erythrocytes. There was no evidence, therefore, to support, the suggested hypothesis. Elimination of this possibility adds weight to the opinion that changes in drug sensitivity of these plasmodia are the result of changes in the properties of drug-binding sites.

Chemical Phenomena↗
PubMed1975

Malaria in studies in vitro. III: the protein synthesising activity of Plasmodium falciparum in vitro after drug treatment in vivo.

Aotus trivirgatus monkeys with established infections of Plasmodium falciparum were treated orally with either chloroquine or the novel compound 1-amidino-3-(3-chloro-4-cyanophenyl) urea. Blood samples were cultured in vitro, 18 hours after treatment, when no morphological abnormalities were apparent. The incorporation of radioactive leucine from the medium by the blood of treated monkeys was compared with that of the undosed control. Parasite maturation was also examined. Both chloroquine and the amidinourea were effective against the drug sensitive strain of P. falciparum. The combined use of an in vivo and in vitro test demonstrated that biochemical disturbance of the parasite may be demonstrable before morphological effects are seen. This system should prove useful in drug metabolism studies and in experiments using large or expensive animals.

Animals↗
PubMed1974

The selection of arylamidinourea antimalarials by their predicted physicochemical properties.

1 A small group of arylamidinoureas for which the predicted physicochemical properties were widely spaced and uncorrelated was selected for study.2 The antimalarial activity of each compound was measured against three species of plasmodium. Three corresponding regression equations were calculated relating the potency of each compound to its predicted physicochemical properties.3 The potency of further test compounds was forecast for each species, by using the corresponding regression equation. These forecasts were compared with the measured activity of the test compounds, and were better than would be expected by chance.4 It is suggested that only a few compounds in a series need be studied initially in order to derive regression equations with worthwhile predictive properties, if the compounds are selected according to appropriate criteria.

Amidines↗