The therapeutic reactivation of fetal haemoglobin

Unusually high levels of fetal haemoglobin production can ameliorate sickle cell disease and beta thalassaemia. Although efforts directed at the pharmacological stimulation of fetal haemoglobin as an approach to managing these conditions have met with limited success, there is wide variation in individual responses. Whether this reflects the particular mutations that underlie these conditions or other genetic factors remains to be determined, as does the ideal combination of agents to achieve this end. These results are encouraging, however, in particular in view of the recent demonstration that other monogenic diseases, Duchenne muscular dystrophy, for example, might be amenable to the same therapeutic strategy.      

Intracardiac extension of intravenous leiomyomatosis

A 42-year-old woman was found to have intravenous leiomyomatosis of the uterus with extension into the inferior vena cava and right atrium. Intravenous leiomyomatosis is a rare neoplastic disease characterized by invasion of venous channels by a benign smooth muscle tumor arising either from the wall of a vessel or from a uterine myoma. Intracardiac extension is often initially misdiagnosed as a right atrial myxoma and may cause death by mechanical obstruction. The diagnosis of intravenous leiomyomatosis should be considered in young women with cardiac symptoms associated with a right atrial mass who also have a pelvic mass or who have previously undergone hysterectomy because of leiomyoma uteri.     

Changes in the interpupillary distance with age and its effect on the near fusion free position

Purpose: The effect of the rate of the interpupillary distance (IPD) change with age on the near fusion free position was investigated in the present study. Methods: Three hundred and fifty-two children aged from 2 to 16 years of age were tested. Interpupillary distance was estimated with a modified Viktorin's method and the near fusion free position was measured with a modified Maddox Wing. Results: The results reveal a significant difference in IPD growth rate between females and males and between children aged below and above 5 years. Most children below 5 years of age were orthophoric, but heterophoria became more common above 5 years of age. Conclusion: The present study suggests that the oculomotor control system for convergence can compensate for age changes in IPD.     

Sperm output of healthy men in Australia: magnitude of bias due to self- selected volunteers

Controversial claims, based on a meta-analysis aggregating 61 heterogeneous observational studies, have been made that human sperm output has decreased by 50% over the last six decades and that this trend may be due to global pollution. If true, such effects should be evident in all areas of the globe; however, longitudinal studies within single centres in Europe and America have produced conflicting results and there are no reports from the southern hemisphere. We therefore reviewed semen analyses obtained from 1980-1995 from 689 healthy men volunteering for screening either as potential sperm donors for a donor insemination programme (n = 509) or to participate in five male contraception research studies (studies no. 1-5, n = 180). All were recruited through the Andrology Unit of the Royal Prince Alfred Hospital, Sydney, by the same doctors using standard methods of recruiting, screening and laboratory examination throughout the period 1980-1995. Recruitment was by advertising without regard to marital or fertility status except in two contraceptive efficacy studies (no. 1 and no. 3) where participants had to be in a stable relationship requiring contraception. Analysing the first semen sample individually or when grouped by year of ejaculation, there was no significant difference in sperm concentration over time or between years or according to year of birth. During the second half of this period, 180 consecutive volunteers were recruited by the same doctors and staff for five male contraception studies. The median sperm concentration for studies no. 1 (103 x 10(6) ml) and no. 2 (142 x 10(6) ml) were significantly (P < 0.05) higher than for studies no. 3-5 (84, 67 and 63 x 10(6) ml, respectively) and for potential sperm donors (median 69 x 10(6) ml). The inconsistency of these estimates illustrates the magnitude of bias (up to 100%) in sperm output that may occur in recruiting groups of self-referred volunteers within a single centre. This highlights the invalidity of extrapolating similar findings on sperm output of self-selected volunteers to the general male community or in using such study groups to characterize sperm output in supposedly 'normal' men.      

Absence of DAZ gene mutations in cases of non-obstructed azoospermia

Sequenced-tagged site (STS) analysis of the Y chromosome long arm (Yq) of azoospermic males has identified a minimum common deleted region of several hundred kilobases in approximately 13% of cases. A candidate azoospermia gene, DAZ (deleted in azoospermia), has been isolated from this region. DAZ has also been shown to be absent in severely oligozoospermic males albeit at a much lower frequency. These data, although highly suggestive, do not constitute formal proof that DAZ actually plays a role in azoospermia, as no small intragenic deletions, rearrangements or point mutations in the gene have been found. In this study we report the screening of DNA from 168 azoospermic/oligospermic males for the presence of the DAZ gene. Deletions involving DAZ were detected in five out of 43 (11.6%) azoospermic males whereas none were found in the remaining 125 oligospermic patients. We present the genomic structure of the 5' end of the DAZ gene together with its sequence analysis in 30 non-obstructed azoospermic males. No mutations in DAZ were found in any of the patients sequenced. These data provide no formal proof that DAZ is AZF. Thus the possibility is still valid that another gene(s) mapping to the deletion interval may be responsible for, or contribute to, the observed phenotypes. Alternatively, if DAZ is AZF, they suggest that the most frequent cause of gene inactivation is via large deletions possibly mobilized by Y chromosome repetitive sequences.      

Potentiation of atracurium neuromuscular blockade by enflurane: time-course of effect

This study was designed to determine the time required for potentiation of atracurium neuromuscular blockade after the introduction of enflurane. Ten ASA physical status I and II adults anesthetized with thiopental, nitrous oxide, and alfentanil were given 0.4 mg/kg atracurium besylate. The force of contraction of the adductor pollicis muscle in response to train-of-four stimulation of the ulnar nerve was recorded. When the first twitch (T1) of the train-of-four recovered to 10% of control, an atracurium infusion was started and adjusted to keep the level of blockade constant. After 15 min of stable blockade, 1.6%-1.7% end-tidal enflurane was started and maintained for up to 2 h. Venous blood samples were drawn and plasma atracurium concentrations were measured 15 min before and 0, 5, 10, 15, 30, 45, 60, 90, and 120 min after the introduction of enflurane. Atracurium plasma concentrations were 730 +/- 127 (SEM) ng/mL at time 0. During the first 30 min, no significant decrease in plasma levels occurred; but at 45 min, concentrations were only 67% +/- 8% of their initial value (P less than 0.01) and 48% +/- 2% at 120 min (P less than 0.01). This suggests that the interaction between enflurane and atracurium is time-dependent. Clinically, the interaction between atracurium and enflurane is negligible during procedures of less than 45 min.