EFFECT OF TEMPERATURE UPON THE CIRCULAR DICHROISM OF BRADYKININ

Analysis of the effect of temperature on the circular dichroism spectrum of bradykinin has led to a more precise understanding of the solution conformation of the peptide. Circular dichroism and ¹³C n.m.r. have been used in a complementary fashion to support the picture that bradykinin spends a maximum of about 20% of its time in a partially ordered conformation featuring a γ-turn with Pro⁷ as the second residue. Since the γ-turn probability is insensitive to temperature, some other conformational effect dominated by the structure of water presumably produces the pronounced change in the circular dichroism spectrum with increasing temperature.     

THE EFFECTS OF SUBMAXIMAL ENDURANCE EXERCISE UPON LH PULSATILITY

The acute effects of submaximal endurance exercise (three consecutive 20-min runs on a treadmill at 50, 60 and 70% of the subjects' maximum oxygen uptake) upon the pulsatile release of LH were compared with those accompanying leisurely strolling for a similar period in seven normally menstruating young women. All trials were conducted during the early to mid-luteal phase, as determined by body temperature patterns, ultrasonic scans of the ovaries, detection of the LH surge in first morning urine specimens, and serial measurements of plasma progesterone. Blood was sampled every 10 min via an indwelling cannula for 8 h before and 12 h after exercise and serum LH measured by radioimmunoassay. LH pulsations were analysed by a time series method. Following cannulation, mean LH levels declined but then rose to reach a maximum 2 h before the beginning of the exercise bout. LH concentrations remained virtually unchanged during exercise itself, and exhibited a declining trend throughout the post-exercise period. The findings in the two groups were similar in all respects, except that in the control study the rate of LH pulsatility was significantly diminished (P less than 0.05) during the first 2 h of sampling as compared with the subsequent 2-h period. The approximate half-life of LH varied from 27 to 57 min, with a mean of 41 min.     

OVARIAN ELECTROCAUTERY VERSUS HUMAN MENOPAUSAL GONADOTROPHINS AND PURE FOLLICLE STIMULATING HORMONE THERAPY IN THE TREATMENT OF PATIENTS WITH POLYCYSTIC OVARIAN DISEASE

Eighty-eight clomiphene citrate-resistant infertile patients with oligomeno-rrhoea or amenorrhoea attributable to polycystic ovarian disease were divided at random into three groups. Twenty-nine patients were treated with ovarian electrocautery, 30 with human menopausal gonadotropins (hMG) and 29 with pure follicle stimulating hormone (FSH). Successful ovulation was induced in 71-4, 70-6 and 66-7% of the cycles in the groups respectively. Ten patients conceived after electrocautery and pure FSH therapy while 15 conceived after hMG medication (chi-squared = 1 -6464, P = 0–439). The six-cycle cumulative pregnancy rate in the three consecutive groups was 521, 55-4 and 38-3%. Four further pregnancies were achieved after treating 10 patients in the electrocautery group with clomiphene citrate (100 mg/day for 5 days) for 25 cycles. The rate of pregnancy wastage in the corresponding groups was 21-4, 53-3 and 40% (chi-squared = 3–127, P = 0–2039). Ovarian electrocautery is equally effective as hMG and pure FSH in the treatment of PCO patients resistant to clomiphene citrate therapy.     

Extradural analgesia in labour

Chloroprocaine hydrochloride 2% and bupivacaine hydrochloride 0.375% in 10-ml doses of plain solutions were studied in a randomised blind manner as the agents for continuous lumbar extradural analgesia in labour. Twenty-four patients were assessed for the speed of onset, duration of action, degree of motor blockade, dermatomal spread, arterial hypotension, and the incidence of unblocked segments. Chloroprocaine showed a quicker onset time and a shorter duration of action than bupivacaine. Chloroprocaine exhibited more marked motor blockade and a lower incidence of unblocked segments. The dermatomal spread and effect on arterial pressure were similar in both groups.     

EXTENSIVE MODIFICATION OF PROTEIN AMINO GROUPS BY REDUCTIVE ADDITION OF DIFFERENT SIZED SUBSTITUENTS

The amino groups of ovomucoid, lysozyme and ovotransferrin have been extensively alkylated by reacting the proteins with various carbonyl reagents in the presence of sodium borohydride. The extent of modification ranged from 40 to 100%. Essentially monosubstitution was obtained with acetone, cyclopentanone, cyclohexanone and benzaldehyde, while 20–50% disubstitution was obtained with N-butanal and nearly 100% disubstitution was obtained with formaldehyde. Both the methylated and isopropylated derivatives of all three proteins were soluble and retained almost full biochemical activities, but introduction of the larger substituents caused precipitation with lysozyme and ovotransferrin.