Exploring a mixture of distributions using Minitab.

A set of macros has been developed to help the user explore the characteristics of the two-component mixture of distributions. Five distributions are included: normal; exponential; Weibull; lognormal; and uniform. Using the powerful abilities of Minitab (version 9) the user can produce graphs for the conditional and unconditional density, cumulative density, survival and hazard functions. The mean of the unconditional distribution is calculated as the weighted average of the conditional means. A technique is programmed for calculating the unconditional median which cannot be derived mathematically. A What..if..? approach can be helpful in clarifying concepts such as sufficient conditions for unimodality, identifiability of mixtures, and hazard function of mixture of distributions.

Hegira adaptation of the NCHS weight and height charts.

The ages of Saudi children are recorded and based on the Hegira calendar. When charted on the National Center for Health Statistics (NCHS) weight and height charts, children will be at disadvantage since the Hegira year is shorter than the Gregorian year. In this paper, centiles for the NCHS reference population are estimated for age in Hegira years from 2-18 for height and weight for both sexes using mathematical interpolation. Charts are prepared for use in hospitals and health centers for children whose ages have been reported based on the Hegira calendar.

Vaginal eversion in a bat tick, Argas (Chiropterargas) boueti Roubaud and Colas-Belcour (Acari: Argasidae).

Vaginal eversion was observed in Argas (Chiropteragas) boueti. During eversion, both cervical and vestibular parts of the vagina are fully everted so that the former is anteriorly oriented, whereas the latter occupies the posterior end of the everted organ. The histology of normal and everted vaginas is described and correlated with its functional and biological significance. Vaginal eversion most likely occurs while the tick is ovipositing and may be involved in the wax-coating process of eggs by Gene's organ.

A model for evaluating the effect of son or daughter preference on population size.

This paper develops a micro probabilistic model to describe the family extension process. The parameters are: the probability that a newborn is a boy (P), the number of desired boys (B), the number of desired girls (G), and the maximum possible number of children (N). This maximum is a stopping rule rather than a biological maximum. The variables are the ultimate number of boys and girls. According to this model, each couple determines B, G, and N, at the beginning of the reproductive period and continues to reproduce until at least B and at least G are achieved, or until the total number of children reaches N. The probability distribution of the ultimate number of boys and girls in the population is derived for this model. Simulation techniques are used to generate offspring. The results showed that the population size increases with the absolute differences, [B-G] for fixed N. They also suggested that son or daughter preference may be an important factor in fertility determinants, which may have important implications in population policies.

Long-term follow-up after recovery from acute myocardial infarction. Observations on survival, ventricular arrhythmias, and sudden death.

A long-term 12-year follow-up of 248 patients surviving acute myocardial infarction indicated a cumulative survival of 89%, 68%, 53%, and 45% for 1, 5, 10, and 12 years, respectively. When patients were assessed with five routinely obtained clinical factors, significant prognostic stratification of high- and low-risk survival groups extended throughout the follow-up period. Sudden cardiac death was found to be twice as frequent as nonsudden cardiac death, but a significant relationship between sudden death and complex ventricular ectopic beats could not be defined. The extent of complex features of ventricular ectopic beats such as pairs, multiform, repetitive, and R-on-T was inversely related to survival. During the first year after acute myocardial infarction, frequency of ventricular ectopic beats was also inversely related to survival. A long-term effect of frequency on survival, however, could not be demonstrated.

A note on the human sex ratio and factors influencing family size in Japan.

A reanalysis of a set of data on the sex distribution of children in Japanese families shows that further increase in family-size is related to the sex of the second child (P less than 0.025). When the second child is male, there is a reduced likelihood of further children. This result is consistent with findings from a U.S. fertility study.

PIP: Data on the sex distribution of children in Tokyo, Japan, originally analyzed by Elmer Gray, Diana Duckworth, and Yujiro Nakajima, are reanalyzed in this one-page article. The results show that a further increase in family size is related to the sex of the second child. "When the second child is male, there is a reduced likelihood of further children."

Corpus luteum function in subdermal levonorgestrel implant users.

PIP: Occurrence of ovulation and corpus luteum function were determined in 16 women inserted with 6 silastic rods, each containing 34 +or- 2mg levonorgestrel, for 1 year. Records of all subjects indicated minimal menstrual disturbances. Mean +or- S.E. serum progesterone levels at days M -7 to M -4 of the menstrual cycle revealed: anovulation (7 subjects) with serum progesterone levels less than 3 ng/ml, inefficient corpus luteum (7 subjects) with progesterone levels of 3-5 ng/ml, and normal ovulation (2 subjects) with progesterone levels above 5 ng/ml. Mean serum estradiol levels determined in the 3 levonorgestrel subgroups were insignificantly different from each other as well as from mean estradiol levels determined in 24 normal ovulatory control women.^ieng

Endocrine profiles in pediatric andrology. II. Insulin-dependent diabetic adolescents.

Seventy-five diabetic male and female children and 75 matched controls were classified according to pubertal staging. Blood samples were assayed for gonadotropins and gonadal hormones. The ultimate adult height in diabetic patients was 5 cm less than that of controls. Almost all diabetic children had a retarded bone age. Levels of serum gonadotropins and gonadal hormones did not differ markedly between diabetic and healthy children. The delay in growth and maturation was not due to hormonal failure, but probably to chronic undernutrition of body cells and failure to utilize the amino acids for protein anabolism related to relative insulin deficiency.

Corpus luteum function in medicated and non-medicated IUD users.

PIP: Serum estradiol and progesterone were determined by radioimmunoassay procedures at premenstrual days M-7 and M-6 in 30 nonlactating women: 1) control non-IUD users (n=10), 2) Lippes loop users (n=10), and 3) copper T 200 users (n=10). Results indicated ovulatory and normal corpus luteum pattern in the 3 groups. Comparable evaluation was performed at premenstrual days M-4 and M-2 in 30 lactating women: 1) control lactating (n=10), 2) copper T 200 users (n=10), and 3) Progestasert TM system users (n=10). Results indicated anovulatory figures in progesterone-releasing device users, and while about 40% of lactating controls and copper T 200 users showed evidence of ovulation, the rest were nonovulatory.^ieng

FSH, LH, E2, progesterone, and testosterone in peripheral blood, spermatic vein, and semen of subfertile men with varicocele.

Peripheral blood (PB), spermatic vein (Sp. V.), and semen samples were collected from 31 subfertile men with varicocele. Levels of FSH, LH, estradiol, progesterone, and testosterone were determined in the three biological fluid compartments using RIA. Remarkable increases in both testosterone and estradiol in the spermatic vein samples, as compared to either peripheral blood or semen, were evident. Correlation coefficient indicated significant positive correlation between PB FSH and each of PB LH, Sp. V. FSH, and Sp. V. LH. Significant positive correlation existed between PB LH and each of Sp. V. FSH, LH, and testosterone. Significant positive correlations were found between PB testosterone and each of Sp. V. testosterone and semen testosterone, as well as between PB estradiol and each of Sp. V. FSH and progesterone. Significant positive correlations between Sp. V. FSH and Sp. V. testicular progesterone was significantly correlated with seminal estradiol.

Subdermal levonorgestrel implants: serum androgens.

Serum levels of androstenedione, dihydrotestosterone, and testosterone were determined by radioimmunoassay procedures in 25 female volunteers using subdermal levonorgestrel implants as a contraceptive. Mean serum androstenedione levels were increased after 1 and 6 months in comparison with preimplantation levels, the increase being significant only after 1 month. This could be attributed to increased production from the adrenal or ovaries and/or changes in clearance rate. Testosterone levels showed approximately 24% increase above basal values after 6 months' use of levonorgestrel implants, which was attributed to concomitant increases in androstenedione levels. The implication of these results is discussed.

Clinical and hormonal studies of subfertile males with varicocele.

To evaluate the hormonal factor in subfertile males with varicocele, FSH, LH, estradiol (E2), and testosterone (T) were assayed both from cubital and spermatic veins. The hormonal profile of patients showed no significant differences from the normal control group. Blood hormonal levels of E2 and T in the testicular veins were much higher than those in the cubital veins while FSH and LH levels showed no significant difference. FSH, LH, and testosterone blood levels in cubital and spermatic veins were statistically correlated. A preoperative hormonal study would be helpful in excluding cases in which varicocele is not the underlying cause of infertility.

Serum-prolactin levels in lactating women using the Progestasert system.

PIP: This study investigates possible changes in serum-prolactin levels in lactating women using the Progestasert system as compared with women fitted with a copper T device and lactating mothers not using any contraceptive method. 46 females (28-35 years of age, parity 1-6) were divided into 2 major groups: 1) 26 menstruating and lactating women (further subdivided into a) control group of 11 normally menstruating women without any contraception; b) 9 Cu T 200 users; and c) 6 Progestasert users); 2) amenorrheic and lactating mothers subdivided into 8 Progestasert users, and 12 Cu T 200 users. No significant differences in the premenstrual and menstrual mean prolactin values were observed in any of the groups. With the onset of menses, a uniform rise in prolactin levels was observed in 3 groups, but was significant only in the Progestasert group. Serum prolactin levels in lactating and amenorrhiec mothers 2 months after delivery showed no significant changes when Cu T 200 and Progestasert IUD users were compared. Further research on this subject should include a matched group of lactating and amenorrheic mothers.^ieng

Corpus luteum function in lactating women using the Progestasert system.

PIP: Serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and progesterone (P) were determined in lactating and menstruating women, 6-8 months after delivery. The subjects were categorized into 3 groups: non-IUD users, copper T-200 (Cu T 200) users, and Progestasert system users. Both types of IUDs were inserted immediately postpartum. When the values of each hormone determined at days M -4 and M -3 were averaged for each subject, remarkable decreases in the grand mean values of FSH, LH, and P were evident in Progestasert users. However, a significant difference was noted between the non-IUD and Progestasert groups for LH only. Considering serum P level as the index of corpus luteum function, the incidence of ovulation, corpus luteum insufficiency and anovulation was 50%, 17%, and 33%, respectively, in the Cu T 200 group; and 17, 33, and 50%, respectively, in the Progestasert group. Similar hormonal determinations were carried out 2 months postpartum in 2 groups of amenorrheic and lactating females fitted with Cu T 200 or Progestasert IUDs immediately after delivery. Results revealed 100% anovulation in the Progestasert group, whereas in the Cu T 200 amenorrheic group, 19, 9, and 72% were ovulating, poor corpus luteum, and anovulating, respectively. These data provide evidence that the Progestasert IUD exerts systemic depressive effect on the hypothalamic-pituitary-ovarian axis in lactating women.^ieng

Serum cortisol level in lactating women using the Progestasert system.

PIP: Premenstrual and menstrual serum-cortisol levels were determined in 3 groups of lactating and menstruating females 6 months after delivery: 1) control not using any contraception (n=11); 2) Progestasert group (n=6); and 3) Copper T 200 group (n=9). All IUDs were inserted immediately postpartum. Another group of women, the amenorrheic and lactating mothers were divided into: 1) Progestasert users (n=8), and Cu T users (n=12). Blood samples were collected from all groups and subjected to cortisol estimation using a competitive protein binding assay according to the method of Baum et al. Comparison of the data obtained revealed decreased levels in both IUD groups as compared to the normal controls at the onset of menstruation. However, the difference was significant only between the non-IUD and Cu T 200 groups. No significant differences between the groups were observed at day M (menstruation)-3. Serum cortisol levels were significantly raised in the control group with the onset of menses, which could be explained on the basis of stress. No significant differences were observed between the two groups of amenorrheic and lactating mothers. It was concluded that the Progestasert IUD system has no effect on cortisol levels in postpartum lactating women.^ieng

Endocrine profile of semen in subfertile males with varicocele.

The semen levels of FSH, LH, estradiol, progesterone, and testosterone were estimated in normal fertile males and in patients with oligozoospermia and varicocele. The only significant difference between the mean values of the two groups was noted for semen LH. Patients with oligozoospermia and varicocele had lower level than the normal fertile males. As a function of prostatic infection, no significant difference was obtained.

Effect of mode of insertion of IUDs on the occurrence of complications.

PIP: The attempt was made to verify whether the mode of insertion of IUDs bears any relations to the subsequent occurrence of complications such as bleeding, pain, and expulsion. The study subjects were 70 women, randomly selected from the Family Planning Clinic of Cairo University Hospitals. Subjects' age ranged from 25-35 years, parity 4-5, with last labor more than 6 months previous. The women were non-lactating, with regular menstrual patterns, and all belonged to the same socioeconomic class. Participants were divided into 7 groups according to the mode of insertion in each group. Insertion was performed on the 5th day of menstruation. The mode of insertion depended basically on the part inside the uterine cavity to which the tip of the device in the inserter was directed before being released: anterior insertion; anterior reversed insertion; posterior insertion; posterior reversed insertion; tip of the loop placed away from the lateral borders; tip touching the lateral border; and the device placed in the middle of the uterine cavity ignoring the direction of its tip in relation to the walls and lateral borders of the uterus. All subjects were followed up and checked for event rates monthly for a 2-year period. The event rates calculated per year of use in each group of different modes of insertion were as follows: 0.3; 0.3; 0.3; 0.2; 0.4; 0.2; and 0.3, per 100 women for the consecutive groups, respectively. No difference was noted between the blind insertion group (group 7) and the other groups. In sum, the incidence of observed complications were not related or restricted to a particular mode of insertion.^ieng