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Biomedical subjects

H Thomas

Publications and source records attributed to H Thomas.

At least 253 records · Page 14Linked to original sources
PubMed1988

Epidural analgesia with a bupivacaine-fentanyl mixture in obstetrics: comparison of repeated injections and continuous infusion.

We compared the efficacy and side-effects of continuous infusion versus repeated injections of epidural bupivacaine-fentanyl during labour. Forty-four parturients were randomly distributed into two groups balanced for population size, morphology and parity. Analgesia was begun at the same stage of labour with a mixture of 20 ml 0.25 per cent plain bupivacaine and 2 ml (100 micrograms) fentanyl. In Group I the initial dose ranged from 8-12 ml as a function of height; an injection of the same dose was repeated immediately upon recurrence of pain. In Group II, after an initial dose of 5-7 ml, a continuous infusion of 3 ml.h-1 was begun, and continued until full dilatation. Analgesia was rated using a pain scale; effects on maternal blood pressure, respiratory rate and neonatal status were noted. Bupivacaine and fentanyl assays were carried out on maternal venous blood in 30 parturients during the course of labour. There was a longer latency to onset of analgesia in Group II (approximately five minutes), followed by a more constant degree of analgesia. This better analgesia cannot be accounted for by a difference in dosage; doses were significantly lower in Group II, despite the fact that labour was of the same duration. The course of labour, and maternal and neonatal status were comparable in the two groups. Assays showed no difference in bupivacaine blood concentrations between the two groups nor signs of drug accumulation. The constant infusion technique is advantageous since it provides a more regular degree of analgesia with lower doses than those required for patients having repeated injections.

Adult↗
PubMed1988

Catabolites of chlorophyll in senescing barley leaves are localized in the vacuoles of mesophyll cells.

Senescing barley leaves accumulate a series of pink pigments with the chemical properties of catabolites derived from chlorophyll. Levels of the major component of this group of pigments were quantified by HPLC and shown to be maximal in tissues exhibiting maximal rates of chlorophyll degradation. Protoplasts were isolated from senescent leaf tissue and fractionated to yield intact vacuoles and plastids. Although small but significant proportions both of total catabolites and of the dominant component of the series were recovered from the plastid fraction, the vast bulk of these compounds could be assigned to the vacuole. These observations suggest a role for the vacuole in the later stages of chlorophyll breakdown during senescence.

Journal Article↗
PubMed1988

Demonstration of the ascending aorta in infective endocarditis by intravenous digital subtraction angiography.

Four patients with infective endocarditis were examined by digital subtraction angiography immediately before operation. In three a root abscess was suspected and the remaining patient was believed to have a false aneurysm at an infected aortic cannulation site. In all the cases digital subtraction angiography showed the structure in several projections and confirmed the presence of a cavity. Subsequent operation confirmed the site and nature of the lesions.

Adult↗
PubMed1988

Rapid pre-operative immunotherapy in a patient allergic to muscle relaxants.

Allergic reactions to muscle relaxants are not uncommon. Although, in most instances, divalent quaternary ammonium salts are involved in these reactions, some monovalent quaternary ammonium compounds can trigger IgE-mediated reactions. A woman who suffered from several episodes of anaphylaxis with divalent (suxamethonium) and monovalent quaternary ammonium salts (tiemonium) needed surgery. Regional anaesthesia was contra-indicated owing to a possible intolerance to local anaesthetics. Investigation confirmed an allergy to monovalent quaternary ammonium salts. Rapid immunotherapy was started with a monovalent quaternary ammonium salt (tiemonium) and subsequently followed by a general anaesthesia using vecuronium. The patient did not develop anaphylactic symptoms.

Adult↗
PubMed1988

Ontario Child Health Study: patterns of ambulatory medical care utilization and their correlates.

Data from a large epidemiologic survey of Ontario children 4 to 16 years of age are presented concerning the frequency and correlates the use of ambulatory medical care services during a 6-month period in which a universal, first-dollar health insurance plan was used. Patterns of use of ambulatory medical care are described for three settings: doctor's offices, emergency rooms, and hospital outpatient departments. A group of children who are frequent users of ambulatory medical care (defined as using three or more services in 6 months) consumed nearly two thirds of all services. Two regression equations are presented--one predicting use/nonuse of ambulatory medical care and the other predicting the total number of visits for medical care. Although only a small proportion of the variance in use/nonuse and amount of use was explained, the major determinant of both ambulatory medical care use and frequency of use was the child's physical health status as perceived by the parent. Younger child, urban area of residence, the number of chronic medical problems of the child, and higher level of maternal education also contributed to the explanation of use v nonuse. Among ambulatory medical care users, high users were more likely to be described as having mental health problems and have parents who had been treated for "nerves." Family size and socioeconomic variables were not important factors in use, suggesting that universal health insurance reduces some barriers to ambulatory medical care for children.

Adolescent↗
PubMed1987

Heterogeneity of growth-hormone receptors detected with monoclonal antibodies to human growth hormone.

The specificity of hormone-receptor interactions has been examined with the aid of monoclonal antibodies (MABs) (EB1, EB2, QA68 and NA71) defining four non-overlapping antigenic determinants on human growth hormone (hGH). The results indicate that growth-hormone receptors in liver obtained from different sources differ with regard to their affinities and relative numbers; they may also differ with respect to the region of the growth-hormone molecule to which they bind. Antibody NA71 effectively inhibited hormone binding to all receptor preparations tested, although with various degrees of potency. Monoclonal antibody EB1 demonstrated a graded inhibition with respect to its ability to block 125I-hGH binding to receptors from various sources, the maximum inhibition being seen in receptor preparations from mouse and ovine liver and the minimum in rat liver. MABs EB2 and QA68 also showed various abilities to inhibit hormone-receptor interaction, depending on the origin of the receptor preparation. Furthermore, the receptor-binding characteristics of hormone-antibody complexes were dependent on whether the binding-site preparation was derived from pregnant, lactating or 'normal' animals. A particularly striking difference between the ability of hormone-MAB complexes to bind to receptors from different sources was seen for microsomes (microsomal fractions) derived from livers of animals of the 'Little' mouse strain. These animals become progressively obese, and it was shown that MABs were considerably more effective in inhibiting 125I-labelled hGH binding to microsomes from phenotypically obese mice than to those derived from their non-obese littermates. The results can be explained by the presence of multiple receptor types for GH, the relative proportions of which vary according to the physiological state of the animal, and possibly between species.

Animals↗
PubMed1987

Malignant lymphoma of bone in children.

From 1960 to 1985 at the Royal Children's Hospital, Melbourne, seven cases of malignant lymphoma of bone (MLB) were identified in children younger than 16 years of age. Over the same period there were 88 cases of Ewing's sarcoma (ES), which illustrates the rarity of MLB. All cases were staged and treated according to protocols current at the time, namely, systemic chemotherapy with radiotherapy to the primary lesions. One child received radiotherapy alone as chemotherapy was not then available (1963). The disease-free five-year survival rate in our small series is 57%, which compares favorably with the 62% that we have calculated from survival data available from 26 previously reported cases of MLB in children and better than the 35% to 50% quoted in adult series of MLB. The main problem in differential diagnosis is distinguishing MLB from ES. A positive diagnosis of MLB rather than ES can be made, however, by observation of the characteristic reticulin staining pattern, the absence of cytoplasmic glycogen, and the ultrastructure.

Adolescent↗
PubMed1987

Praziquantel impairs the ability of exogenous serotonin to stimulate carbohydrate metabolism in intact Schistosoma mansoni.

Praziquantel (PZQ) (Droncit, Biltricide) at 10 microM completely abolishes the stimulatory effect of serotonin on glucose uptake and lactate excretion of Schistosoma mansoni. Fluoxetine (FXT) exerts similar effects on the serotonin-induced stimulation of glucose uptake and lactate excretion, however, at 100-fold higher concentrations. In comparison with PZQ, which is inhibitory at 10 microM, FXT and other amphiphilic cationic drugs (amitriptyline, propranolol, imipramine, chlorpromazine) inhibit glucose uptake or lactate excretion in schistosomes at 1 mM; the strongest inhibitor is FXT. Glycogen breakdown is maximally stimulated by PZQ in the absence or presence of serotonin. There is an additive effect of 50 microM chlorpromazine or FXT and 0.01 to 0.1 microM PZQ on glycogen breakdown. The rate of sodium-sensitive or insensitive serotonin uptake in Schistosoma mansoni is reduced by 10 microM PZQ by about 40%, as is the sodium-sensitive excretion of serotonin. The results show that PZQ interferes with the ability of serotonin to stimulate carbohydrate metabolism. The possibility that PZQ may act through an effect on tegumental integrity is discussed.

Animals↗
PubMed1987

Chlorpromazine, other amphiphilic cationic drugs and praziquantel: effects on carbohydrate metabolism of Schistosoma mansoni.

The effects of the amphiphilic cationic drugs chlorpromazine, imipramine, amitriptyline, propranolol and fluoxetine and praziquantel were investigated on glucose uptake and lactate excretion of Schistosoma mansoni. While praziquantel enhances glucose uptake and lactate excretion at a concentration of 10(-7) M, all the other drugs exert the same effects at concentrations above 10(-5) M. Generally, a constant molar ratio of 1:2 is found between glucose uptake and lactate excretion. Above 10(-5) M, praziquantel inhibits glucose uptake and lactate excretion. Similar effects are caused by amphiphilic cationic drugs at 10(-3) M. Pre-incubation of S. mansoni with 10(-5) M praziquantel completely abolish the stimulation of carbohydrate metabolism by serotonin and by 5 X 10(-5) M chlorpromazine or fluoxetine. The action of praziquantel on S. mansoni resembles that of amphiphilic cationic drugs with respect to their influence on carbohydrate metabolism. This, together with data obtained from electrophysiological and electron microscopic studies, provides evidence for the hypothesis that praziquantel exerts its effect by interacting with membrane structures.

Amitriptyline↗
PubMed1987

Day case laparoscopic sterilization--time for a rethink?

The postoperative experiences of 50 women undergoing laparoscopic sterilization as a day case procedure were sought together with the views of their general practitioners. The women were not visited routinely at home and few contacted their general practitioners. All the women had chosen day care but one-third of those eventually discharged on the day of the operation wished that their stay had been longer; most of their general practitioners seemed unaware of these feelings. The importance of adequate discussion with the patient about postoperative pain is reviewed. The arrangements for postoperative care following the patient's return to the community is discussed.

Ambulatory Surgical Procedures↗
PubMed1987

Pulmonary function in smokers after short-term cessation of alcohol ingestion.

To test whether acute alcohol withdrawal has an effect on pulmonary function, we studied 33 smoking alcoholics admitted for a four-week period of rehabilitation during which they consumed no alcohol. Flow-volume curves, lung volumes by body plethysmography, and single breath diffusing capacity for carbon monoxide were measured on admission, at two weeks, and at four weeks. We found no significant change in pulmonary function between the results on admission and after four weeks of abstinence from alcohol. We conclude that short-term cessation of alcohol did not significantly influence pulmonary function in our subjects.

Adult↗
PubMed1987

Evaluation of an integrated community antenatal clinic.

The obstetric outcome and experience of care of 96 pregnant women attending an integrated community antenatal clinic staffed by general practitioners, a community midwife and an obstetric accredited senior registrar were compared with those of 100 women receiving traditional shared antenatal care. The views of the women and their practitioners were sought; obstetric data were obtained from obstetric notes, hospital records and cooperation cards.Fewer women attending the community clinic suffered from hypertension than women receiving shared care. The women attending the clinic reported that it had a friendly, relaxed and personal atmosphere. They also reported less inconvenience and a shorter waiting time for the obstetrician than women receiving shared care. They received greater continuity of care from the obstetrician but less from the general practitioners and community midwives than the control women. There was greater satisfaction with communication with staff among women attending the clinic, with the exception of the midwife whose role was not sufficiently well delineated. Practitioners in the integrated scheme appreciated the close working arrangements but experienced an increase in administrative tasks.

Community Health Services↗