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Biomedical subjects

J Saunders

Publications and source records attributed to J Saunders.

At least 145 records · Page 8Linked to original sources
PubMed1984

A laboratory assessment of ciprofloxacin and comparable antimicrobial agents.

The in vitro activity of ciprofloxacin against a wide range of bacterial isolates was assessed in comparison with norfloxacin, enoxacin, co-trimoxazole and penicillin (or ampicillin) where appropriate. Minimal inhibitory concentrations (MICs) indicated that ciprofloxacin was highly active against gram-negative bacilli of the Enterobacteriaceae and Pseudomonas groups, notably against strains resistant to gentamicin. Similarly, Staphylococcus aureus (including methicillin-resistant strains) and Haemophilus influenzae were susceptible, regardless of penicillinase production. Norfloxacin and enoxacin were less active than ciprofloxacin against the majority of species tested, although enoxacin blood levels were generally higher. Most co-trimoxazole-resistant strains were susceptible to the quinoline group of drugs.

Anti-Bacterial Agents↗
PubMed1983

Congenital rubella in Israel following the 1978-79 rubella epidemic.

We conducted a retrospective survey of children who were born with congenital rubella syndrome (CR) resulting from a recent rubella epidemic. Sources of information were hospital and laboratory records and data collected in an active search for deaf children born following the epidemic and attending rehabilitation centers for the deaf (Micha). Criteria for inclusion in the survey were: 1) major clinical defects, and 2) one or more of the following positive laboratory findings--virus isolation, presence of rubella-specific IgM antibodies, or the presence of hemagglutination inhibition (HI) antibodies in children beyond the age of 1 year. Excluded from the study were 28 children with persistent HI antibodies, but without clinically detected defects. CR was identified in 45, among them 43 with deafness. Other major defects were psychomotor retardation, microcephaly, cataracts and heart defects. Transient abnormalities included encephalitis, hepatosplenomegaly, jaundice, thrombocytopenia, intrauterine grown retardation and failure to thrive. Thirty-one mothers (70%) reported a history of clinical rubella in pregnancy, the others having experienced subclinical infection. Multiple defects were found in children born following early gestational rubella (less than 2 months); abnormalities also occurred as a consequence of rubella as late as the fifth month of gestation.

Antibodies, Viral↗
PubMed1982

Isotope turnover studies in uncontrolled diabetes and the effects of insulin.

Turnover rates of glucose, free fatty acids (FFA) and leucine have been measured in newly diagnosed, uncontrolled insulin-dependent diabetic (IDD) patients. The results have been compared with data collected from the same patients while on conventional insulin therapy as well as after overnight intravenous infusion of insulin with sustained normoglycaemia. The data have been analysed by compartmental and non-compartmental methods and the results have been compared with simultaneously collected data on respiratory exchange. Oxidation rates of 14C-labelled substrates have also been measured. Tracer studies were done on established diabetics after insulin withdrawal and subsequent intravenous infusion of insulin at different rates. The results confirm the in vivo importance of the glucose-fatty acid cycle, indicating that when glucose, FFA and ketone bodies are available in excess it is FFA and ketones that are metabolized in preference to glucose. The data emphasize the importance of increased production rates rather than decreased utilization rates in producing high concentrations of substrates in the plasma of insulin-deficient patients.

Blood Glucose↗
PubMed1981

A comparison between propranolol, practolol and betaxolol (SL75212) on the circulatory and metabolic responses to insulin-induced hypoglycaemia.

1. Six healthy male volunteers received equivalent intravenous beta-blocking doses of propranolol, practolol and betaxolol (SL75212) or saline at weekly intervals Sixty minutes later 0.1 unit/kg insulin was given intravenously. 2. In all studies, maximum hypoglycaemia (mean 1.2 mmol/l) was reached thirty minutes after insulin. Recovery from hypoglycaemia was delayed with propranolol but practolol and betaxolol had no effect. 3. Propranolol blocked the tachycardia and widening of pulse pressure seen in saline treated subjects. It also blocked the rebound rise in free fatty acids (FFA) and glycerol concentrations that followed the nadir of hypoglycaemia. 4. Neither practolol nor betaxolol had significant effects on pulse rate or blood pressure but betaxolol resembled propranolol in blocking the rebound rise in FFA and glycerol, while practolol blocked the rise in glycerol alone. 5. The magnitude of the rise in growth hormone following hypoglycaemia was similar in all groups, but the peak was earlier after practolol and betaxolol.

Adrenergic beta-Antagonists↗
PubMed1981

The effect of non-selective and selective beta-1-blockade on the plasma potassium response to hypoglycaemia.

The effect of non-selective beta-blockade with propranolol, beta 1-selective blockade with betaxolol and of saline on the plasma potassium response to insulin induced hypoglycaemia was examined in six healthy subjects. Although propranolol retarded the recovery from hypoglycaemia, the degree of hypokalaemia was significantly (p less than 0.01) less than with saline or betaxolol, which had similar effects. Adrenergic mechanisms may modulate potassium disposal through a beta 2 receptor.

Adrenergic beta-Antagonists↗
PubMed1981

Isotypic discordance of paraproteins and lymphocyte surface immunoglobulins in myeloma.

B lymphocyte surface immunoglobulins (Smlg) were studied in 24 patients with multiple myeloma by means of anti-isotypic antisera, and their heavy and light chain isotypes were compared in each patient with those of the paraprotein. In 21 patients, lymphocyte Smlg consisted of only one light chain type, and in 16 of only 1 heavy chain type. However, the Smlg and paraprotein heavy and light chain types were identical in only 5 patients while in 6 they differed in heavy and light chain types, in 7 in light chain type, and in 4 in heavy chain type. In 2 patients with light chain myeloma, Smlg light chains were isotypically the same as the paraprotein. Isotypic discordance between paraprotein and Smlg may signify the proliferation of a second malignant clone with failure to differentiate into secreting plasma cells. Alternatively, it is conceivable that the lymphocyte Smlg could have the same idiotypic specificity as the paraprotein despite the isotypic differences, but this will require further studies using anti-idiotypic antisera.

Adult↗
PubMed1980

Glucose and free fatty acid turnover in thyrotoxicosis and hypothyroidism, before and after treatment.

Glucose and free fatty acid (FFA) turnover (RT) were measured by isotopic methods in groups of patients with thyrotoxicosis and hypothyroidism and compared with normal subjects. Patients with thyrotoxicosis were then studied after treatment with oral propranolol and again after treatment with carbimazole. Patients with hypothyroidism were studied again after treatment with thyroxine. Glucose RT was increased by about a third in thyrotoxicosis (12.7 mumol. min.-1 kg-1 +/- 1.0 SEM compared to 9.5 +/- 0.5 in normal subjects) while FFA RT was doubled (12.5 mumol. min.-1 kg-1 +/- 1.2 compared to 6.3 +/- 0.9 in normals). Propranolol was without effect, but carbimazole normalized these variables. In hypothyroidism both glucose and FFA RT were normal (9.1 +/- 0.7 and 6.7 +/- 0.9 respectively). Mean glucose and FFA RT both rose following thyroxine treatment, but not significantly; the post-treatment values remaining within the normal range (10.3 +/- 0.7 and 7.0 +/- 1.3 respectively). Oxidation of FFA, as estimated by 14CO2 excretion, was increased in thyrotoxicosis (42.8% +/- 2.9 SEM compared to 34.8 +/- 2.3 in normal subjects) and fell with carbimazole treatment (34.7 +/- 4.1). In hypothyroid subjects FFA oxidation increased following thyroxine treatment (from 34.4 +/- 4.1). In hypothyroid subjects FFA oxidation increased following thyroxine treatment (from 34.4 +/- 3.3 to 46.2 +/- 3.6).

Adult↗
PubMed1980

Comparative in vitro appraisal of piperacillin, including its activity against Salmonella typhi.

Piperacillin was evaluated in vitro against 711 clinical isolates of aerobic and anerobic gram-positive and gram-negative bacteria, including 76 isolates of Salmonella typhi. Piperacillin minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were compared with those of a range of beta-lactam, aminoglycoside, and other antimicrobial agents, and inoculum size effects were considered. The relationship between dilution and disk diffusion tests was studied by regression analysis. In addition, piperacillin was assessed in combination with aminoglycoside and other beta-lactam drugs. This investigation has confirmed the activity of piperacillin against a broad range of bacteria, including Pseudomonas, Enterobacteriaceae, Neisseria, beta-lactamase-negative Haemophilus influenzae, and Staphylococcus aureus as well as enterococci, Bacteroides fragilis, and other anaerobes. All strains of Pseudomonas aeruginosa were inhibited by </=32 mug/ml or less, demonstrating again the potential usefulness of piperacillin in the treatment of pseudomonal infections. S. typhi proved susceptible to piperacillin, all isolates being inhibited by 1 mug/ml. Inoculum size experiments showed that inocula of 10(8) CFU resulted in MICs and MBCs appreciably higher than those resulting from inocula of 10(6) CFU, and inocula of 10(2) CFU resulted in MICs and MBCs appreciably lower than those resulting from inocula of 10(4) CFU. Piperacillin was active against all gentamicin-resistant pseudomonads tested, but not against gentamicin-resistant klebsiellas and enterobacters. Combinations of piperacillin with tobramycin and amikacin were consistently synergistic against Pseudomonas and Serratia isolates. Less consistent results were shown when piperacillin was combined with aminoglycosides or cephalothin against Klebsiella and indole-positive Proteus isolates, although synergy was observed in most cases. Occasional antagonistic reactions were encountered with piperacillin-cephalothin or piperacillin-tobramycin combinations against the latter isolates.

Anti-Bacterial Agents↗
PubMed1979

Glucose and free fatty acid turnover in normal subjects and in diabetic patients before and after insulin treatment.

Turnover rates of glucose and free fatty acids were measured, using 3H-glucose and 14C-l-palmitic acid as tracers, in insulin-requiring diabetic patients at presentation and after insulin treatment. Correlations were sought with rates of substrate oxidation, determined independently from respiratory exchange, and with plasma hormone concentrations. The rates of appearance of glucose and of free fatty acids were increased in the diabetics to 17.6 and 10.2 micronmol min-1 kg-1 respectively. Both rates fell to normal (13.3 and 7.1 micronmol min-1 kg-1) after insulin. In the untreated state there was an inverse relationship between the rates of utilisation of glucose and free fatty acids (r = 0.61; p less than 0.05). It is suggested that this relationship represents the impairment of peripheral glucose utilisation by free fatty acids and by ketone bodies in vivo, so far only demonstrated in vitro. The tracer calculated rates of glucose utilisation correlated well over a wide range with the respiratory quotient in untreated diabetics, while respiratory quotient was inversely related to free fatty acid turnover rates. In untreated diabetics plasma cortisol and 3,3', 5'-triiodothyronine (rT3) were increased whereas thyroxine and 3,5,3'-triiodothyronine (T3) were decreased. 3,5,3'-Triiodothyronine concentration was closely related to the metabolic clearance rate of glucose (p less than 0.05), while cortisol concentrations correlated with glucose production (p less than 0.02) and blood ketone body concentration (p less than 0.02). It is concluded that glucose overproduction is the major contributor to the hyperglycaemia of untreated diabetes.

Adult↗