20 Years of Legislation - How Australia Has Responded to the Challenge of Regulating Genetically Modified Organisms in the Clinic

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In contrast to the prior voluntary system, since 2001, gene technology in Australia has been regulated under a legislated national Gene Technology Regulatory Scheme which is administered by the Gene Technology Regulator.

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The Scheme provides science-based assessment of the potential risks of gene technology to the health and safety of people and the environment.

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It complements the role of the Australian Therapeutic Goods Administration which regulates all therapeutic products in Australia to ensure they are safe and effective.

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Recent reforms to the Scheme contribute to, and anticipate, the continued safe development and delivery of gene-based human therapeutics in Australia as a successful model for other jurisdictions.

Langerhans cell migration is modulated by N-sulfated glucosamine moieties in heparin

Dendritic cell (DC) migration into and out of tissues is important for the generation of primary immune responses to antigens encountered in tissues. In order to study the mechanisms involved in DC migration we used a skin explant system and quantitated the number of Langerhans cells (LC), which are immature precursors of DC in skin-draining lymph nodes, remaining in the epidermis in response to incubation with various biomolecules. This paper shows that LC trafficking in epidermis is a metabolically active process that is modulated by heparin, specifically by N-sulfated glucosamine moieties in heparin. This is the first demonstration of structural specificity in the biochemical requirements for DC migration in a tissue and therefore is important to understanding DC migration in general.

Sulphatide-binding properties are shared by serum amyloid P component and a polyreactive germ-line IgM autoantibody, the TH3 idiotype

Serum amyloid P component (SAP) concentration was elevated in sera from leprosy patients, significantly so above endemic controls in lepromatous cases. In the sera of lepromatous leprosy (LL) patients who experienced an erythema nodosum leprosum (ENL) episode the SAP fell at the onset of ENL and remained low throughout, in two of three cases. Changes in SAP concentration parallel anti-sulphatide IgM concentrations. TH3, a monoclonal IgM germ-line antibody derived from a LL patient, and SAP share similar binding patterns. In this study we demonstrate binding to heparin and sulphatide. Moreover, SAP inhibited the binding of TH3 to sulphatide, as well as anti-sulphatide IgM found in a range of sera, and anti-sulphatide IgG in the only sera sample in which it was found. The observation that anti-TH3 idiotype monoclonal and polyclonal anti-SAP antibodies both inhibited the binding of TH3 and IgM in sera (but not IgG) to sulphatide without binding to sulphatide themselves further demonstrated similar binding specificities. The observations of similarity in binding reinforce ideas that SAP may function as a primitive opsonin, but the clear ability to inhibit binding of autoantibodies suggests that SAP may play a role in ameliorating tissue and particularly nerve damage in leprosy patients.

Modulation of MHC class II+ Langerhans cell numbers in corticosteroid treated epidermis by GM-CSF in combination with TNF-alpha

It is important to understand how dendritic cells (DC) are recruited, maintained and stimulated to migrate from tissues to lymph nodes. This is because DC are potent initiators of primary immune responses and candidates for vaccine development. Identification of factors which could lead to increased numbers of DC in tissues could affect immune responses by modulating their interaction with antigen which penetrates the tissue. To identify cytokines which could increase DC in tissues we tested the ability of GM-CSF, TNF-alpha and IL-6 to partially prevent steroid depletion of Langerhans cells (LC) from the epidermis. Cytokines diluted in serum-containing medium were compared with cytokines diluted in albumin-containing, serum-free medium in order to determine a minimum combination of cytokines required to increase LC and the effect of serum on the LC-increasing activity of cytokines. In the presence of serum, GM-CSF or TNF-alpha could increase LC frequency compared to the control; but in the absence of serum neither of these cytokines were effective unless they were combined with each other. In the presence of serum the combination of GM-CSF with TNF-alpha was ineffective. The data support the hypotheses that GM-CSF and TNF-alpha are both important in regulating LC numbers in the epidermis in vivo. Serum may modulate how each of these cytokines, separately or in combination, affect LC frequency in the epidermis - GM-CSF and TNF-alpha separately probably interact with other factors present in serum to increase LC frequency, whereas in combination it is possible that these separate effects are cancelled in the presence of serum. TNF-alpha and GM-CSF together, in the absence of serum, form one combination of a minimum number of cytokines which can regulate LC frequency in the epidermis; and IL-6 alone, or in combination with GM-CSF, does not increase LC frequency.

Modulation of Ia+ Langerhans cell numbers in vivo by cultured epidermis derived supernatants and by GM-CSF

This paper demonstrates that epidermal cells in culture produce an activity which can increase the frequency of Ia+ epidermal Langerhans cells (LC). This was achieved by treating mice topically with a mixture containing supernatant derived from primary culture of murine epidermis (ES) and a synthetic corticosteroid, triamcinolone acetonide (TAC). The presence of the supernatant in the mixture partially protected the Ia+ LC from depletion by the steroid. The Ia+ LC frequency increasing activity was measured as the difference between the Ia+ LC frequency due to treatment with steroid mixed with supernatant and the Ia+ LC frequency due to treatment with steroid mixed with negative control medium. The mean frequency of Ia+ LC in epidermis treated with TAC mixed with ES was 606(SD 43) cells/mm2, as compared with 486 (SD 68) cells/mm2 in the epidermis treated with TAC mixed with control medium. The activity appeared to be caused by (a) proteinaceous factor(s). A fraction of ES which was retained above a > or = 10 KDa molecular weight cut-off membrane was capable of partially protecting Ia+ LC frequency from TAC depletion. Supernatants from cultured lymph nodes, dermis as well as the squamous cell carcinoma lines T7 and T79, but not the human osteosarcoma cell-line 143B, also contained similar activities. We demonstrate that GM-CSF also increased the number of Ia+ epidermal LC when applied topically to mouse skin in this system. Therefore, using this Ia+ LC frequency modulation system, we propose that GM-CSF is one example of a cytokine which may be involved in the regulation of Ia+ LC numbers in epidermis and that epidermal cells produce factors which can increase the number of Ia+ LC.

A new method for rate of analgesic onset: two doses of intravenous morphine compared with placebo

A new method of frequent early pain assessments for 1 hour only was used to determine time of onset of analgesia after intravenous administration of 10 mg morphine, 5 mg morphine, or placebo in a double-blind study; 79 patients were randomized if they required parenteral analgesia in the early postoperative period. Pain intensity was determined by a four-point categoric verbal rating scale and on a verbal ordinal scale from 0 to 100 (0 = no pain, 100 = worst pain imaginable) during the first hour after analgesic administration. The onset time of analgesia, assessed by 50% of patients achieving 25% reduction from their baseline pain assessment, was significantly faster for 10 mg morphine compared with 5 mg morphine (p = 0.02) and placebo (p less than 0.01). More familiar analgesic efficacy measures, including the sum of pain intensity differences and time to next analgesic dose, similarly showed the superiority of 10 mg morphine to placebo in the first hour, confirming sensitivity according to the conventional paradigm.

H2 antagonists and bupivacaine clearance

The effect of the H2 receptor antagonists cimetidine and ranitidine on bupivacaine clearance was assessed in women scheduled to undergo elective Caesarean section under epidural anaesthesia. Thirty-six women were randomly allocated to receive either no medication, cimetidine 400 mg or ranitidine 150 mg on the night prior to and on the morning of surgery. No significant difference was found between the peak bupivacaine levels: the mean (SD) values were 0.74 (0.17) microgram/ml, 0.81 (0.38) microgram/ml and 0.70 (0.24) microgram/ml in the control, cimetidine and ranitidine groups, respectively. Similarly, the H2 receptor antagonists did not alter the plasma bupivacaine against time curves, half-life or bupivacaine clearance in the three groups studied.

Noninvasive measurement of gastric emptying in obstetric patients

An epigastric impedance technique was used to measure gastric emptying in nonpregnant women, women in the third trimester of pregnancy, and women within 60 min of delivery. The basis of the technique is the increase in epigastric impedance after the ingestion of a nonionic fluid. The subsequent decline in impedance is used as a measure of gastric emptying. The impedance epigastrograph used consisted of a four-electrode array (two source, two detector) that was applied over the epigastrium. The method was sufficiently sensitive to measure the effects of pregnancy, labor, and narcotics on gastric emptying. There was no difference in the rate of gastric emptying between pregnant and nonpregnant females. Labor appeared to cause a significant delay in gastric emptying; the mean +/- SEM time taken for the gastric volume to decrease to 50% (T0.5) was 7.2 +/- 0.6 min during pregnancy and 13.0 +/- 1.9 min in the immediate postpartum period. However, the principal factor associated with the delay in gastric emptying in the group studied within 60 min of delivery was probably the use of meperidine and promethazine, because there was a significant difference (P less than 0.05) between subjects who received meperidine and promethazine during labor and those in another group who had received either no analgesia or extradural analgesia, the T0.5 values for the two groups being 18.2 +/- 4.0 and 10.3 +/- 1.4 min, respectively.

Two hundred out-patient laparoscopic clip sterilizations using local anaesthesia

Female sterilization using clips applied laparoscopically under local anaesthesia was used in 200 women. Apart from two patients in whom there were technical difficulties, the operation was completed without complication and without immediate or delayed morbidity. The technique, which avoids the risks of general anaesthesia, is commended as a safe, simple method of sterilization suitable for, and acceptable to, the majority of women.

Noninvasive assessment by radiotelemetry of antacid effect during labor

A noninvasive radiotelemetry technique was used to study the antacid effect of 15 ml of 0.3 M sodium citrate in 26 women in established labor. The subjects swallowed a pH radio pill, whose signal was detected transabdominally by a radio receiver. The median and range of values for the time to return to the preantacid basal pH for all of the women in labor was 84.0 (11.8-195.8) min. However, there was a significant difference (P less than 0.05) in the duration of action of sodium citrate between the women who had received no analgesia and those given intramuscular meperidine. The median and range of values for the time to return to the preantacid basal pH in patients who had received meperidine during labor was 166.0 (147.7-195.8) min, whilst in those who had received no analgesia the values were 56.7 (11.8-143.0) min. There were no significant differences between patients given no analgesia and those given extradural analgesia. Pretreatment with intravaginal prostaglandins (PGE2) did not influence antacid effect.

The assessment of gastric acidity and antacid effect in pregnant women by a non-invasive radiotelemetry technique

Non-invasive radiotelemetry techniques were used for the in-vivo assessment of gastric acidity and the effect of antacids in non-pregnant women and women in the third trimester of pregnancy. A particulate (magnesium trisilicate mixture) and a non-particulate (sodium citrate) antacid were studied. There was no significant difference in basal gastric acidity and gut transit time between the pregnant and non-pregnant subjects. The median and range of values for the efficacy (defined as the integrated area under the pH/time curves) of sodium citrate was 138.3 pH.min (29.8-520.7) in the non-pregnant and 103.0 pH.min (54.3-375.6) in the pregnant subjects. The median and range of values for the duration of action of sodium citrate were 38.6 (18.1-147.4) min in the non-pregnant and 30.5 (20.0-119.1) min in the pregnant women. Magnesium trisilicate mixture resulted in a greater intragastric pH change and had a greater efficacy than sodium citrate, but the duration of action of the two antacids was similar.

Does twice the volume of antacid have twice the effect in pregnant women at term?

The clinical effect of doubling the administered volume of a nonparticulate antacid (0.3M sodium citrate) was investigated in pregnant females using a radiotelemetry technique. The subjects swallowed a pH radio pill and the signal was detected transabdominally by an aerial connected to a radio receiver. In vitro studies showed that twice as much acid would be titrated to pH 2.0 when the volume of sodium citrate was doubled. The in vitro studies indicated that there was no significant difference between 15 ml and 30 ml of sodium citrate. The median duration of action of 15 ml of sodium citrate was 30.5 min compared with 42.1 min for 30 ml of sodium citrate. The area under the pH vs time curve was used as a measure of antacid efficacy. The median value for 15 ml of sodium citrate was 103.0 pH X min and for 30 ml of sodium citrate was 126.5 pH X min. The most likely explanation for the difference between in vitro and in vivo studies is that gastric emptying is the predominant factor influencing antacid effect in patients.