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Biomedical subjects

D Savva

Publications and source records attributed to D Savva.

At least 37 records · Page 2Linked to original sources
PubMed1995

Comparison of total intravenous, balanced inhalational and combined intravenous-inhalational anaesthesia for tympanoplasty, septorhinoplasty and adenotonsillectomy.

Two hundred and thirty-five consecutive Saudi patients aged between two and fifty-three years undergoing elective tympanoplasty (n = 32), septorhinoplasty (n = 68) or adenotonsillectomy (n = 135) were studied. They were randomized to receive either a total intravenous anaesthetic (10 ears, 23 noses, 44 throats) consisting of propofol for induction of anaesthesia followed by a propofol infusion, a combined intravenous-inhalational anaesthetic (11 ears, 22 noses, 46 throats) consisting of the above with isoflurane in oxygen-enriched air, or a balanced inhalational anaesthetic (11 ears, 23 noses, 45 throats) consisting of thiopentone for induction of anaesthesia and oxygen in nitrous oxide with isoflurane for maintenance. During tympanoplasty, all three anaesthetic techniques produced stable heart rates and arterial pressures. During septorhinoplasty, blood pressure rose in patients who received total intravenous anaesthesia, while combined and balanced techniques produced haemodynamic stability. During adenotonsillectomy, total intravenous anaesthesia produced a rise in both heart rate and blood pressure, the combined technique produced a rise in heart rate alone while balanced anaesthesia produced haemodynamic stability. Postoperatively, vomiting, pain scores and analgesic requirements were similar following all three types of anaesthetic within each surgical site subgroup. Our findings support the choice of balanced inhalational anaesthesia for all three types of ENT surgery and, where cost and facilities permit, total intravenous anaesthesia for tympanoplasty and combined intravenous-inhalational anaesthesia for septorhinoplasty.

Adenoidectomy↗
PubMed1995

Reduced expression of a naturally deleted form of human proopiomelanocortin complementary deoxyribonucleic acid after transfection into Chinese hamster ovary cells.

POMC is the precursor molecule for a number of hormones, ACTH, MSH, and beta-endorphin. The human genomic sequence has been elucidated, but to date the complete human complementary DNA (cDNA) sequence has not been published. Here we report the cloning and expression of human POMC cDNA from the anterior pituitary gland. Two forms of POMC cDNA have been identified; one sequence agrees with the cDNA sequence predicted from the published genomic sequence, and the second is a variant with a 9-base pair deletion (corresponding to the loss of three amino acids, Ser-Ser-Gly, between residues 67-73). Both POMC cDNA sequences have been expressed in Chinese hamster ovary cells. A significant difference was observed between the levels of expression in the cells and the amount secreted into the media of the two protein precursor molecules. The expression of the deleted variant in the cells was 16.4 +/- 0.9% of the level of normal POMC (P < 0.001), and in the media the deleted variant was 22.4 +/- 2.2% of the level of normal POMC (P < 0.001).

Amino Acid Sequence↗
PubMed1995

The use of lignocaine to reduce pain on i.v. injection of diluted nalbuphine.

A randomized, placebo-controlled, double-blind study was conducted on 66 healthy patients aged 10-61 years undergoing elective ear, nose and throat surgery to assess the incidence and severity of pain associated with intravenous (i.v.) injection of diluted nalbuphine HCl given during induction of general anaesthesia, and to determine the efficacy of adding lignocaine (2 mg mL-1) to nalbuphine to reduce this pain. Injection of saline produced pain of low intensity in 15% of patients and a withdrawal response in 3% of patients. Injection of nalbuphine mixed with lignocaine produced a significantly higher incidence (36%; P < 0.025) and severity (P < 0.025) of pain than saline, but a similar number of responses (6%) to pain. The diluted nalbuphine alone produced the highest incidence (61%) of pain (P < 0.01 vs. saline, P = NS vs. nalbuphine with lignocaine), which was most severe (P < 0.01 vs. saline, P < 0.025 vs. nalbuphine with lignocaine), and caused the highest number (27%) of withdrawal responses (P < 0.01 vs. saline, P < 0.025 vs. nalbuphine with lignocaine). We conclude that diluted nalbuphine 2 mg mL-1 produces pain on i.v. injection into peripheral veins, and that this can be significantly reduced by adding lignocaine 2 mg mL-1 to the solution.

Adolescent↗
PubMed1994

Prediction of difficult tracheal intubation.

Three hundred and fifty consecutive patients (322 non-obstetric, 28 obstetric; 185 female) were assessed before operation using the modified Mallampati test and by measuring thyromental and sternomental distances, forward protrusion of the mandible and interincisor gap with the mouth fully open. Tracheal intubation was difficult in 17 (4.9%) patients, of whom four (1.14%) had a grade III or IV view on laryngoscopy. A sternomental distance of 12.5 cm or less with the head fully extended on the neck and the mouth closed predicted 14 of the 17 patients in whom tracheal intubation was difficult. As a screening test, sternomental distance appeared to be more sensitive (82.4%) and more specific (88.6%) than thyromental distance (64.7% and 81.4%, respectively), the modified Mallampati test (64.7% and 66.1%, respectively) and forward protrusion of the mandible (29.4% and 85.0%, respectively). The interincisor gap ranged from 2.0 to 5.0 cm in all patients except one. There was no correlation between the interincisor gap and the view on laryngoscopy (P > 0.05, one-way ANOVA). There was also no difference in mean interincisor gap between those patients who presented no difficulty with tracheal intubation and those who did (P = 0.7-0.8, two sample t test). Sternomental distance may be a useful bedside screening test for preoperative prediction of difficult tracheal intubation.

Adolescent↗
PubMed1994

Analgesics and ENT surgery. A clinical comparison of the intraoperative, recovery and postoperative effects of buprenorphine, diclofenac, fentanyl, morphine, nalbuphine, pethidine and placebo given intravenously with induction of anaesthesia.

1. Vomiting and restlessness following ENT and eye surgery are undesirable, and may be related to the emetic and analgesic effects of any analgesic given to augment anaesthesia during surgery. 2. To rationalise the choice of analgesic for routine ENT surgery we examined the intraoperative, recovery and postoperative effects following the administration of either buprenorphine (3.0 to 4.5 micrograms kg-1), diclofenac (1 mg kg-1), fentanyl (1.5 to 2.0 micrograms kg-1), morphine (0.1 to 0.15 mg kg-1), nalbuphine (0.1 to 0.15 mg kg-1), pethidine (1.0 to 1.5 mg kg-1) or saline (as control) given with the induction of anaesthesia in 374 patients. A standardised anaesthetic technique with controlled ventilation using 0.6-0.8% isoflurane in nitrous oxide and oxygen was employed. The study population constituted 7 similar groups of patients. 3. Intraoperatively, their effects on heart rate and blood pressure, airway pressure and intraocular pressure, were similar. This implies, most surprisingly, that neither their analgesic nor their histamine releasing effects were clinically evident during surgery. By prolonging the time to extubation at the end of anaesthesia, only buprenorphine, fentanyl, morphine and pethidine provided evidence of intraoperative respiratory depression. 4. Postoperatively, buprenorphine was associated with severe respiratory depression, prolonged somnolence, profound analgesia and the highest emesis rate. Diclofenac exhibited no sedative, analgesic, analgesic sparing, emetic or antipyretic effects. Fentanyl provided no sedative or analgesic effects, but was mildly emetic. Morphine provided poor sedation and analgesia, delayed the requirement for re-medication and was highly emetic. Nalbuphine and pethidine produced sedation with analgesia during recovery, a prolonged time to re-medication and a mild emetic effect. None provided evidence, from analysis of postoperative re-medication times and analgesic consumption, of any pre-emptive analgesic effect. 5. We conclude that nalbuphine (mean dose 0.13 mg kg-1) and pethidine (mean dose 1.35 mg kg-1), given individually as a single i.v. bolus during induction of anaesthesia, are the most efficacious analgesics for routine in-patient ENT surgery.

Adolescent↗
PubMed1993

Application of the polymerase chain reaction to the diagnosis of human toxoplasmosis.

Toxoplasmosis may cause significant damage to the developing fetus and is a life-threatening opportunistic infection in immunocompromised persons. Serological investigation is unreliable, while isolation of the parasite is time consuming and may lack sensitivity. We have developed a system for detecting Toxoplasma gondii based on the amplification of the P30 gene using sequential rounds of PCR and nested primers. The clinical value of this technique was assessed by the investigation of a range of tissues taken from pregnant women, fetuses, neonates, AIDS patients and organ graft recipients. The PCR assay produced more positive reactions than isolation of the parasite by means of cell culture or animal inoculation. Extended autoradiography was found to be more sensitive than stained agarose gels for detecting the PCR product. Systematic contamination of PCR reactions was avoided but it was not possible to exclude sporadic contamination in certain cases. Detection of specific DNA is of clinical value in the investigation of the pregnant woman in order to assess the risk of transplacental passage of infection and in the fetus and neonate to identify congenital toxoplasmosis. Even so, PCR findings must be interpreted with caution because of the risk of a sample being contaminated. PCR may be the investigation of choice when brain biopsy is performed on a patient with AIDS and when toxoplasmosis associated with bone marrow transplantation is suspected.

AIDS-Related Opportunistic Infections↗
PubMed1993

Controlled ventilation with the Bain co-axial system. A rationalisation of gender-related minute volume requirements and carbon dioxide replacement therapy.

The minute ventilation required to maintain either hypocapnia (FE'CO2 = 4.0 kPa, group A, n = 36) or normocapnia (FE'CO2 = 5.0 kPa, group B, n = 38) in 74 adult patients was determined for the Bain system with controlled ventilation at 10 breath.min-1 and fresh gas flow equal to minute ventilation. Males required a greater minute ventilation and fresh gas flow than females (p < 0.01) in each group (group A, males approximately 90 ml.min-1.kg-1, females approximately 80 ml.min-1.kg-1; group B, males approximately 75 ml.min-1.kg-1; females approximately 65 ml.min-1.kg-1). Where capnography is not available, it may be safer to ventilate patients' lungs using the minute volume and fresh gas flow requirements established in group A patients. The administration of 5% carbon dioxide in oxygen for 2 min safely re-established normocapnia and spontaneous respiration in hypocapnic patients when ventilated with the same minute volume, fresh gas flow and respiratory rate required during surgery. Only one patient required greater than 400 ml.min-1 of carbon dioxide to produce a 5% concentration. Maximum flow from the carbon dioxide flowmeter may be restricted to 400 ml.min-1 rather than the 500 ml.min-1 currently recommended.

Adolescent↗
PubMed1992

Confirmation of assignment of the bovine K-casein locus by PCR.

The provision of a bovine gene map will allow the ready identification of genetic disease in cattle and will lead to the identification of the genetic loci responsible for quantitative traits of economic importance. An extension of the polymerase chain reaction to the identification of linkage in bovine-Chinese hamster cell hybrids has improved the speed and facility of the assignment of genes to linkage groups and thus makes it easier to achieve a bovine linkage map.

Animals↗
PubMed1992

Diagnosis of toxoplasma infection in cardiac transplant recipients using the polymerase chain reaction.

Cardiac biopsy samples taken from transplant recipients around the time of primary toxoplasma infection were investigated by conventional histology and amplification of the P30 gene of Toxoplasma gondii by the polymerase chain reaction (PCR). Toxoplasma was detected more frequently by PCR than histology which may reflect the enhanced sensitivity of the former technique. Further studies are required to determine the optimal amount of tissue which should be examined by each technique and to develop a PCR assay capable of distinguishing between quiescent infection and active toxoplasmosis.

Animals↗