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Biomedical subjects

N Mackenzie

Publications and source records attributed to N Mackenzie.

At least 19 recordsLinked to original sources
PubMed2005

Recurrent nodal metastases in the posterior triangle: implications for treatment of the atypical tumour.

We studied the incidence of recurrent nodal metastases in level V (posterior triangle) in patients who had previously had a staging or therapeutic dissection of the neck, with or without postoperative radiotherapy. Of 160 patients studied (177 neck dissections), 41 (26%) developed recurrent metastases in the neck. Four patients (3%) developed ipsilateral recurrent disease in level V. In these four patients, level III or IV lymph nodes were shown histologically to have extracapsular spread at the time of the original dissection. All four metastases were located at or just beyond the anatomical boundaries of the posterior triangle. None of the metastases at level V were from oral or oropharyngeal primary tumours.

Adult↗
PubMed2005

Hypoxia-inducible factor 1alpha in oral cancer.

BACKGROUND: Hypoxia is a common feature of many cancers. It contributes to local and systemic tumour progression as well as potentially compromising radiotherapy and chemotherapy. Hypoxia-inducible factor 1alpha (HIF-1alpha) is an essential component in changing the transcriptional response of tumours under hypoxia. It targets the transcription of over 60 genes involved in many aspects of cancer biology including cell survival, glucose metabolism, cell invasion and angiogenesis. METHODS: In this review, we discuss the relevant literature on HIF-1alpha with specific emphasis on oral cancer. We also present some of our preliminary data on HIF-1alpha in oral cancer. RESULTS: Although there are a few conflicting reports of its prognostic significance, over expression of HIF-1alpha seems to play an adverse role in the malignant progression of head and neck cancer by facilitating the adaptation of cells to hypoxia as well as contributing to the invasive properties and angiogenesis in these tumours. CONCLUSIONS: HIF-1alpha has an important role to play in pathophysiology of oral cancer, both under normal and hypoxic conditions. The pharmacological manipulation of HIF-1alpha has marked effects on tumour growth, and it could prove to be an important target for drug therapy, both in oral cancer and in other hypoxia-dependent disease states.

Cell Hypoxia↗
PubMed2004

Hypoxia-inducible factor 1 (HIF-1) in cancer.

Hypoxia is a common feature of many cancers. It contributes to local and systemic tumour progression as well as potentially compromising radiotherapy and chemotherapy. Hypoxia-inducible factor 1 (HIF-1) is an essential component in changing the transcriptional response of tumours under hypoxia. It targets the transcription of over 60 genes involved in many aspects of cancer biology including cell survival, glucose metabolism, cell invasion and angiogenesis. Over-expression of HIF-1 has been associated with increased patient mortality in several cancer types including breast, stomach, cervical, endometrial and ovarian cancers. The pharmacological manipulation of HIF-1 has marked effects on tumour growth, and it could prove to be an important target for drug therapy, both in cancer and in other hypoxia-dependent disease states.

Cell Hypoxia↗
PubMed2004

Anal function following third degree tears.

OBJECTIVE: To assess the anal function of women who have suffered a third degree perineal tear during parturition. PATIENTS: Fifty-three consecutive women who sustained a third degree tear, between January 1998 and March 2000, at the Princess Anne Maternity Unit, Royal Bolton Hospital were assessed. METHODS: Women were assessed at 3 months post partum using the Cleveland Clinic Incontinence Score, digital assessment of anal sphincter and endo-anal ultrasound scan. RESULTS: At 3 months post partum 75% of the participants had no symptoms of anal incontinence, 18% had mild symptoms and 7% had more severe symptoms. Anal endosonography demonstrated normal anal sphincters in 66% of participants, an abnormality in the external sphincter in 29% and a defect in both sphincters in 2%. There was poor correlation between symptoms and scan defects. CONCLUSION: The incidence of anal incontinence following repair of a third degree tear was not high and it is unlikely that we are missing a hidden pool of symptomatic women. No major change in management policy is required. The routine assessment of anal function in women who had sustained a third degree tear was appreciated by the women and enabled us to identify the small portion of women with significant symptoms.

Anal Canal↗
PubMed2002

Comparison of cyclizine and ondansetron for the prevention of postoperative nausea and vomiting in laparoscopic day-case gynaecological surgery.

Seventy-four patients undergoing laparoscopic gynaecological surgery were randomly allocated to two groups receiving cyclizine 50 mg or ondansetron 4 mg at induction of anaesthesia. Anaesthetic and postoperative analgesia regimens were standardised. Approximately half of the patients in each group experienced some degree of postoperative nausea and vomiting (cyclizine, 56%; ondansetron, 54%). There was no difference between groups in respect of pre- and postdischarge incidence. Mean (SD) time to eye opening was significantly prolonged in the cyclizine group [10 (4) min vs. 8 (2) min; p < 0.001], but this had no influence on discharge times. Cyclizine and ondansetron appear equally effective in preventing postoperative nausea and vomiting but the 10-fold price differential favours cyclizine.

Adult↗
PubMed1998

Comparison of S(-)-bupivacaine with racemic (RS)-bupivacaine in supraclavicular brachial plexus block.

Bupivacaine is used widely as a local anaesthetic but has potential for severe cardiovascular and central nervous system (CNS) toxicity. It has an asymmetric carbon atom giving it a chiral centre, and the commercial preparation is a racemic mixture of its two enantiomers: dextro or R(+)-bupivacaine and levo or S(-)-bupivacaine. Preclinical studies have demonstrated reduced cardiotoxicity and CNS toxicity for S(-)-bupivacaine. In this study we have compared the clinical efficacy of S(-)-bupivacaine with racemic RS-bupivacaine for supraclavicular brachial plexus block in 75 patients undergoing elective hand surgery. Patients received 0.4 ml kg-1 of either 0.25% or 0.5% S(-)-bupivacaine or 0.5% RS-bupivacaine in a randomized, double-blind study. Clinical assessments of sensory and motor block were performed at regular intervals. There were no significant differences in onset time, dermatomal spread or duration of both sensory and motor block between the three groups (the power of the study was 81% to detect a 4-h difference in duration). Duration of sensory block was prolonged with wide interpatient variation: 892 (SD 250) min, 1039 (317) min and 896 (284) min for 0.25% S(-)-bupivacaine, 0.5% S(-)-bupivacaine and 0.5% RS-bupivacaine, respectively. There were no differences in the overall success rate of the technique. We conclude that S(-)-bupivacaine was suitable for local anaesthetic use in brachial plexus block anaesthesia.

Adult↗
PubMed1996

Sedation during regional anaesthesia: indications, advantages and methods.

Patient management is a vital component of regional anaesthesia, and the appropriate method and level of sedation must be chosen for each patient on an individual basis. This may range from simple distraction through pharmacologically induced anxiolysis or hypnosis, to light general anaesthesia by the inhalational or intravenous routes. Intravenous sedation is most widely used and suitable agents include the benzodiazepines, the intravenous induction agents and the opioids. Currently, midazolam and propofol are considered to be the most suitable drugs. Patient safety must never be compromised and pharmacological sedation must be administered by a trained practitioner, with appropriate patient monitoring and provision of supplementary oxygen.

Anesthesia, Conduction↗
PubMed1993

Sedation with propofol during surgery under local blockade. Assessment of a target-controlled infusion system.

The ability of a target-controlled propofol infusion system to provide sedation for 40 patients undergoing surgery under regional blockade was assessed. Eighty-eight per cent of the total infusion time was at the desired sedation level with little oversedation. This was achieved with a median blood propofol concentration of 0.93 micrograms.ml-1. The pharmacokinetic algorithm performed as well when used for sedation as for total intravenous anaesthesia. The predicted and measured blood propofol concentrations showed a bias of -12% and a precision of 34%.

Adolescent↗
PubMed1988

A comparison of propofol and midazolam by infusion to provide sedation in patients who receive spinal anaesthesia.

Twenty patients scheduled for orthopaedic surgery under spinal anaesthesia received by intravenous infusion either 1% propofol or 0.1% midazolam at a rate adjusted to maintain adequate sedation as judged on a five-point scale. No other anaesthetic or analgesic drugs were given. The mean time to reach the required level of sedation was similar in both groups and the quality and ease of control of sedation were good in all patients. Mean infusion rates were 3.73 mg/kg/hour for propofol and 0.27 mg/hg/hour for midazolam. Airway maintenance was excellent and there were no side effects other than restlessness of the arms in one patient in each group. Recovery, judged by ability to open the eyes and recall date of birth, was significantly more rapid after propofol than after midazolam (2 and 10 minutes respectively after the end of infusion) and two patients in the latter group were unduly drowsy in the initial postoperative period. Pre- and postoperative amnesia were greater in the midazolam group but no patient had recall of peri-operative events. Psychometric tests showed significantly better recovery of higher mental function after propofol for up to 2 hours after surgery.

Anesthesia Recovery Period↗
PubMed1987

AIDS--risk behaviours and AIDS knowledge in intravenous drug users.

Surveys of intravenous drug users were undertaken in July 1985 and one year later to assess behaviours which could result in risk of HIV infection and transmission. Ready availability of sterile syringes was reported by 48% in 1986 and 63% in 1985. Sharing of syringes amongst intravenous drug users is a common practice. In 1986, 22% of subjects reported no sharing of syringes, 16% sharing with one and 62% with between 2 and 20 others. There was a significant trend towards less sharing, and improved sterilisation of syringes in 1986. Nearly all subjects were aware of the risks of HIV transmission via shared syringes. In 1985, 19% of subjects reported adopting safer-sex practices compared with 28% in 1986. A history of prostitution was reported by 50% of women. All subjects were aware intravenous drug users had been asked not to donate blood, and none reported having done so within five years. All the subjects tested for HIV antibody were negative.

Acquired Immunodeficiency Syndrome↗