Accidental subarachnoid catheter insertion.
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Adult↗
Biomedical subjects
G Lyons
Publications and source records attributed to G Lyons.
Doxorubicin selectively inhibits muscle gene expression in cardiac muscle cells in vivo and in vitro.
The anthracycline antibiotic doxorubicin produces a characteristic myopathy in cardiac muscle that limits its use in cancer therapy. We have shown in cultured neonatal rat cardiac muscle cells that doxorubicin treatment resulted in a rapid, selective decrease in the expression of muscle-specific genes, which preceded other changes characteristic of doxorubicin cardiomyopathy. Doxorubicin selectively and dramatically decreased the levels of mRNA for the sarcomeric genes, alpha-actin, troponin I, and myosin light chain 2, as well as the muscle-specific, but nonsarcomeric M isoform of creatine kinase. However, doxorubicin did not affect nonmuscle gene transcripts (pyruvate kinase, ferritin heavy chain, and beta-actin). Actinomycin D, an inhibitor of DNA-dependent RNA polymerase, did not show a similar selective decrease of muscle-specific mRNAs but, rather, produced a nonspecific, dose-dependent decrease of muscle and nonmuscle transcripts. The doxorubicin effect on muscle gene expression was limited to cardiac muscle; cultured skeletal myocytes were resistant to the effects of doxorubicin at 100-fold greater doses than those causing changes in mRNA levels in cardiac muscle cells. These effects of doxorubicin were reproduced in vivo; rats injected with doxorubicin showed a dose-dependent decrease in the levels of mRNAs for alpha-actin, troponin I, myosin light chain 2, and M isoform of creatine kinase in cardiac but not skeletal muscle. These selective changes in gene expression in cardiocyte cultures and cardiac muscle precede classical ultrastructural changes and may explain the myofibrillar loss that characterizes doxorubicin cardiac injury.
Actins↗
Needlestick injuries in anaesthetists.
A survey of needlestick injuries among 42 anaesthetists at this university hospital was carried out over a 3-month period to ascertain the rate of occurrence and the extent to which a revised protocol for the management of such injuries was followed. There were nine reported incidents, of which six were with contaminated needles. Three were reported. Eight anaesthetists had not taken up immunisation against hepatitis B. The rationale behind the revised protocol, and possible reasons for poor compliance are discussed.
Accidents, Occupational↗
An evaluation of a 30-gauge needle for spinal anaesthesia for caesarean section.
A 30-gauge spinal needle was evaluated for Caesarean section, using a combined epidural/spinal technique, in 50 mothers. Spinal anaesthesia failed in six mothers and was inadequate in another six. General anaesthesia was required on one occasion. A 25% overall failure rate suggests that a 30-gauge needle is not a practical proposition for routine clinical practice.
Adult↗
Monitoring the fetus with a pulse oximeter during a caesarean section.
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Cesarean Section↗
Expression of two myogenic regulatory factors myogenin and MyoD1 during mouse embryogenesis.
MyoD1 and myogenin are muscle-specific proteins which can convert non-myogenic cells in culture to differentiated muscle fibres, implicating them in myogenic determination. The pattern of expression of MyoD1 and myogenin during the early stages of muscle formation in the mouse embryo in vivo and in limb-bud explants cultured in vitro, indicates that they may have different functions in different types of muscle during development.
Animals↗
Caesarean section at 27 weeks gestation with removal of phaeochromocytoma.
We describe the anaesthetic management of a 31-yr-old woman undergoing combined Caesarean section and removal of phaeochromocytoma during the 27th week of pregnancy. The technique used (general anaesthesia with extradural block) provided good operating conditions and a relatively stable haemodynamic state.
Adrenal Gland Neoplasms↗
The venous flow augmentation pump: a solution to venous congestion.
Venous congestion is a well-recognized cause of failure of survival of replanted digits. When re-exploration of a venous congested digit is not possible, an alternate solution is presented. A description of the venous flow augmentation pump is provided, along with a preliminary case report of its successful use.
Aged↗
Synthesis and turnover of late H2B histone mRNA in developing embryos of the sea urchin, Strongylocentrotus purpuratus.
In sea urchins, "early" histone proteins are synthesized during cleavage and blastula formation, "late" histone proteins in subsequent stages of development. To understand the molecular mechanisms responsible for this ontogenic switch in histone subtype synthesis, we determined the absolute amounts, rates of synthesis, and rates of turnover of late H2b histone mRNAs during development. We showed previously that late H2b mRNA comprises several mRNA isotypes. In this study, we used both a class-specific DNA probe to measure the amounts of the late H2b mRNA isotypes collectively, and a gene-specific probe to measure amounts of a particular late H2b mRNA encoded by a gene known as L1. We found that the amount of late H2b mRNA increased dramatically from 85,000 molecules per embryo in the 16-hr blastula to a peak of 670,000 molecules per embryo in the 24-hr mesenchyme blastula, and fell to 380,000 molecules per embryo in the 72-hr pluteus larva. The L1 late H2b mRNA achieved its maximum abundance earlier than the late H2b mRNA class as a whole, reaching a peak of 34% of total late H2b in the 14-hr blastula and declining to 7% in the pluteus larva. Measurements of the rate of incorporation of [3H]uridine into late class H2b mRNA, performed by a novel in vivo isotope incorporation method, enabled us to calculate both synthesis rates and half-lives of late H2b mRNA during development. These calculations showed (1) that the increase in late H2b mRNA level between 16 and 24 hr postfertilization is regulated primarily if not entirely at the level of mRNA synthesis; and (2) that the half-life of late H2b mRNA is comparatively short, around 20 min, at all stages examined.
Animals↗
Comparison of extradural buprenorphine and extradural morphine after caesarean section.
Fifty-seven women received extradural morphine 3 mg, buprenorphine 0.18 mg or buprenorphine 0.09 mg after elective Caesarean section carried out under extradural bupivacaine. Supplementary sublingual buprenorphine was available on demand. Ten-centimetre visual analogue pain scores were completed regularly; emesis, pruritus and urinary retention were recorded for 24 h. Patients who received buprenorphine 0.09 mg had more pain, and required more supplementary analgesia, than those who received morphine 3 mg. Pain scores and analgesic requirements after buprenorphine 0.18 mg were not significantly different from either of the other two groups. Emesis was not significantly different in the three groups. More itching occurred after morphine 3 mg and buprenorphine 0.18 mg than after buprenorphine 0.09 mg; pruritus of the face, legs and perineum was more common after morphine than buprenorphine. Twenty-eight percent of patients without a urinary catheter developed retention of urine. Seventy-five to 84% of patients were satisfied with analgesia during the first day after operation. Analgesia and adverse effects were similar when morphine 3 mg or buprenorphine 0.18 mg was given extradurally after Caesarean section.
Buprenorphine↗
Unintentional dural puncture.
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Anesthesia, Epidural↗
Myocardial infarction in the third trimester of pregnancy.
A 30-year-old woman developed severe chest pain while out shopping and was admitted to the delivery suite. She was 38 weeks pregnant with her second child. A diagnosis of myocardial infarction was made and cardiac arrest occurred shortly afterwards. She went into spontaneous labour 30 hours later and was delivered vaginally. This report reviews myocardial infarction in pregnancy and considers the clinical management of this patient.
Adult↗
Development & use of a recovery room for the delivery suite.
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Anesthesiology↗
The effects of fruit juices and fruits on the absorption of iron from a rice meal.
The effects of the chemical composition of fruit juices and fruit on the absorption of iron from a rice (Oryza sativa) meal were measured in 234 parous Indian women, using the erythrocyte utilization of radioactive Fe method. The corrected geometric mean Fe absorptions with different juices varied between 0.040 and 0.129, with the variation correlating closely with the ascorbic acid contents of the juices (rs 0.838, P less than 0.01). Ascorbic acid was not the only organic acid responsible for the promoting effects of citrus fruit juices on Fe absorption. Fe absorption from laboratory 'orange juice' (100 ml water, 33 mg ascorbic acid and 750 mg citric acid) was significantly better than that from 100 ml water and 33 mg ascorbic acid alone (0.097 and 0.059 respectively), while Fe absorption from 100 ml orange juice (28 mg ascorbic acid) was better than that from 100 ml water containing the same amount of ascorbic acid (0.139 and 0.098 respectively). Finally, Fe absorption from laboratory 'lemon juice' (100 ml orange juice and 4 g citric acid) was significantly better than that from 100 ml orange juice (0.226 and 0.166 respectively). The corrected geometric mean Fe absorption from the rice meal was 0.025. Several fruits had little or no effect on Fe absorption from the meal (0.013-0.024). These included grape (Vitis vinifera), peach (Prunus persica), apple (Malus sylvestris) and avocado pear (Persea americana). Fruit with a mild to moderate enhancing effect on Fe absorption (0.031-0.088) included strawberry (Fragaria sp.) (uncorrected values), plum (Prunus domestica), rhubarb (Rheum rhaponticum), banana (Musa cavendishii), mango (Mangifera indica), pear (Pyrus communis), cantaloup (Cucumis melo) and pineapple (Ananas comosus) (uncorrected values). Guava (Psidium guajava) and pawpaw (Carica papaya) markedly increased Fe absorption (0.126-0.293). There was a close correlation between Fe absorption and the ascorbic acid content of the fruits tested (rs 0.738, P less than 0.0001). There was also a weaker but significant correlation with the citric acid content (rs 0.55, P less than 0.03). Although this may have reflected a direct effect of citric acid on Fe absorption, it should be noted that fruits containing citric acid also contained ascorbic acid (rs 0.70, P less than 0.002).(ABSTRACT TRUNCATED AT 400 WORDS)
Absorption↗
The fate of intravenously administered hepatic ferritin in normal, phenylhydrazine-treated and scorbutic guinea-pigs.
When highly purified hepatic 59Fe-ferritin was injected intravenously into normal guinea-pigs more than half of it was taken up by red cell precursors and the iron was used for haem formation. This was studied in more detail in animals in which a reticulocytosis had been induced either by phenylhydrazine or by repeated venescetions. 55% of the injected ferritin iron was found in reticulocytes at 1 h. Experiments using ferritin doubly labelled with 59Fe and 125I indicated that the whole molecule was taken up, with two-thirds of the radioactivity being associated with the membrane at 1 h and one third being already within the cell. There was a progressive loss of 125I activity over the ensuing hours, while most of the 59Fe was slowly internalized and incorporated into haem between 1 and 24 h. In contrast, 90% of the activity taken up by red cell precursors from 59Fe-transferrin was present as haem at all times. The liver and spleen were the two other major sites of 59Fe-ferritin uptake in phenylhydrazine treated animals. While there was an early uptake of 59Fe into haem in these organs, some redistribution occurred with time, since most of the 59Fe was in a non-haem fraction by 24 h. In a final experiment the distribution and fate of 59Fe-ferritin was studied in scorbutic animals treated with phenylhydrazine. The findings were similar to those in normals similarly treated, which suggests that ferritin iron was being effectively mobilized for haem formation despite the ascorbic acid depletion.
Animals↗
Adenosine triphosphate levels in human spermatozoa.
ATP levels in human spermatozoa have been positively correlated with good motility. This has given rise to the impression that good ATP levels per se are related to good motility, i.e., the higher the ATP level, the better the motility and fertilizing potential. There was no direct correlation between motility percentage, forward progression, viability percentage, and ATP levels (when expressed per 1 million spermatozoa) in the general population. This finding was not unexpected since other factors, such as defects of the microtubules and viscosity of the semen, could affect the motility in some patients. However, when semen from individual patients was assessed, the motility percent, viability, and ATP concentration decreased by comparable levels over a 4-h period postejaculation. Semen samples with normal counts of spermatozoa (greater than 20 X 10(6)/ml) had higher levels of ATP than samples from patients with oligozoospermia. Spermatozoa from patients whose semen contained less than 0.60 X 10(-2) nmol ATP/1 million spermatozoa showed a rapid drop in motility over a 4-h period compared with semen samples where the motility remained above 10% motile over this period, the latter samples having ATP levels averaging 3.30 X 10(-2) nmol/1 million spermatozoa.
Adenosine Triphosphate↗
Spinal anaesthesia with hyperbaric lignocaine for elective caesarean section.
This study was carried out in 30 patients undergoing elective Caesarean section to assess the predictability and reliability of spinal anaesthesia with 5% hyperbaric lignocaine, with a view to incorporating the technique in our failed intubation drill. The spinal was performed with a 25-gauge needle in either the sitting (15 patients) or left lateral position (15 patients). The speed of onset of anaesthesia to T6 was significantly faster (p less than 0.01) in the lateral group, but the duration of action was similar in both groups. Twelve patients had hypotension and four developed severe postspinal headaches. The block progressed to the C2 dermatome in four patients and was associated with dysphagia. This was totally unpredictable and may be due to altered cerebrospinal fluid dynamics in late pregnancy. Therefore, the use of spinal anaesthesia with heavy lignocaine may be inadvisable in obstetric patients, especially following failed intubation.
Anesthesia, Obstetrical↗
Sleep and comfort after caesarean section.
To compare postoperative well-being after general and epidural anaesthesia, 58 women undergoing Caesarean section were divided into a general anaesthetic group receiving intramuscular opioid postoperatively (26), and an epidural group receiving morphine via the epidural route (32). The epidural group required less analgesia (p less than 0.01 at 0.5 and 8 hours, p less than 0.001 at 4 hours). There was no difference in the use of oral analgesics. At 1, 4 and 24 hours after delivery more patients in the general anaesthesia group described themselves as very comfortable (p less than 0.05). More in the epidural group had a very good night's sleep during each night studied. Patients in the epidural group were slower to use the ward toilet (p less than 0.01) and had more itching (p less than 0.001). Our conclusion is that patients progressed well in both groups.
Adolescent↗