In the Louisville Twin Study, pairs of 3- and 4-year-old twins were provided with standardized competitive or cooperative tasks in a laboratory setting. Some tasks required a pair of twins to share toys; other fostered a more competitive engagement between the twins. Behavioral ratings identified temperament and social components at both ages, and between the two ages, there were transformations in the links between the components. Parental ratings of the twins' temperament at the same ages were moderately correlated with the laboratory observations, but the pattern of the relations changed from one age to the next. The combined sets of measures were subjected to twin analyses for 43 pairs of twins. The results are discussed in terms of the similarity of MZ and DZ pairs for the dimensions of temperament and the transformations of temperament.

The Authors refer the results of a genetical, clinical and statistical research on a group of 265 patients with cancer of the prostate. The data show a significant familiar incidence only for the cancer of the same site.

The twinning incidence from 1984 to 1993 was investigated in Campinas, State of São Paulo, Brazil, and the analyzed data were combined with previous series from the same population. This study has shown that the mean annual incidences and the standard deviations for DZ, MZ and DZ plus MZ twins for the period of 1984 to 1993 are estimated respectively as 4.7 ± 0.92, 4.1 ± 1.11, and 8.8 ± 0.87 per 1,000. In the same period the mean annual incidence of triplets was 0.15 ± 0.16. It was also shown that the incidence of DZ twins is steadily decreasing since 1925, while the incidence of MZ pairs, after a period of decline is increasing since the sixties, due perhaps to the widespread use of oral contraceptives. Concerning the twinning rate as a whole, it has been shown that its declining trend has disappeared over the last few years.

As a part of a study of the dietary habits of monozygotic twins, a nutrition survey including a 24-hour dietary recall interview and a three-day dietary diary was conducted on the members of 15 male and 13 female pairs of identical Caucasian twins ranging from 25 to 61 years of age. In this study, overall mean caloric, protein, fat, and carbohydrate intake of males was significantly greater than females. Members of male twin pairs also tended to be more similar than female twins in mean intake of all major nutrient groups. In general, the observed differences in overall intake between males and females were maintained even after adjustment of body weight. Male twins were characterized by greater similarity in intake of sodium and potassium; however, there was no consistent difference in the degree of correlation in intakes of members of male and female twins for either iron, calcium or phosphorus.

Results on genetic variability in some of the morphometric characters on head and face, body girths and skin folds, based on 45 MZ and 67 like-sex DZ twin pairs, are presented. The data were subjected to a method which eliminated possible biases in the estimated genetic variances that could result from heterogeneity of total variances between zygosities of the 17 head and face measurements, heterogeneity was observed for only bizygomatic diameter. Head breadth means differed between MZ and DZ twins, indicating bias in the trait's genetic variance analysis. The results indicated a significant genetic component in these morphometric traits. For 11 girth and skinfold measurements, the t'-test based on hierarchical structure of twin data, also failed to reveal any appreciable difference between the mean values of MZ and DZ twins. Heterogeneity of total variance between zygosities was observed for three skinfold measurements, ie, biceps, triceps and suprailiac. The girth measurements, however, did not reveal any heterogeneity of total variances between the zygosities. The estimates of genetic variance revealed stronger genetic component for the girths than for the skinfolds.

The AA. have studied the characteristical steps of the first and permanent dentition on 408 twin pairs (156 MZ and 252 DZ). These phenomena appear to be significantly genetically controlled. According to the AA., the hereditary units might possess a characteristic potential time span, which is a function of an energetic genetically conditioned charge. This parameter of the hereditary unit is called Chronon.

Precision of zygosity determination in twins can be improved by the use of modern methods of DNA analysis. The clinical application of 4 single- (SLS) and 2 multi-locus (MLS), and 6 PCR (polymerase chain reaction) systems for zygosity determination in 12 twin pairs with oral clefts was compared with regard to the quality and quantity of sample material required and the probability of error in monozygosity determination. PCR systems proved to be superior to SLS or MLS, as DNA sampling is much more convenient, while its level of accuracy still fulfils clinical requirements. For this reason, PCR systems should be considered a basic method in modern clinical twin research.

Multiple pregnancy is NEVER planned. A few years ago one could categorically make such a statement. Perhaps nowadays one cannot be so sure. Although parents are still unlikely to be able to plan such an event, it does seem that current infertility treatments may allow or even encourage practitioners to use methods which predispose to a multiple pregnancy. The practice of returning several fertilised embryos to the uterus in the hope of achieving a successful result has meant that many parents who longed for a baby have had to adjust to the realisation of a multiple pregnancy with all the effects such an occurrence has on family physical, social and emotional resources.

The Study of Triplets and Higher Order Births by the Office of Population Censuses and Surveys [1] highlighted the striking increase in Multiple Births in recent years. This was particularly evident in the case of triplets and higher order births. (Fig. 1) Care of these high-risk infants is costly in resources and no increased funding has been given to the National Health Service or Social Services budgets to provide care and support for the families.

This study endeavours to ascertain the needs of such families preconceptually, antenatally, intra-partum, postnatally and in the early months following the birth. It also tries to assess how appropriate current practice is in meeting these needs.

A dermatoglyphic analysis has been carried out in 7 boys and 5 girls affected by Noonan's syndrome. No deviation from the general population values was found with respect to individual quantitative value, A line termination, absence of C line, a-b ridge count, hypothenar patterns, and presence of p proximal triradius on soles.

Whorls were however increased on fingertips and the axial triradius t, as in Turner's syndrome, was in 21% of the cases in position t′ or t″.

The Gm(1), Gm(2), Gm(4), Gm(12), and Inv(1) factors were studied in the sera of 56 patients suffering from rheumatoid arthritis and 26 from various rheumatic diseases, by the hemagglutination inhibition test, using optimally reacting mixtures of Ragg and Nagg sera. The distribution of these factors was found to agree with that of healthy Greeks. No correlation was found between hypergammaglobulinemia and the discovery of the Gm(1) and Inv(1) factors. The presence of the rheumatoid factor was independent of the Gm and Inv phenotypes.

Taste thresholds for phenylthiourea were measured among 900 Caucasoid leprous patients and among 1000 healthy Caucasoid control males, of the State of São Paulo, Brazil.

The frequency of non-tasters among the leprous sample (19.7%) is significantly lower than that found among the healthy sample (24.7%). These results suggest a correlation between taste ability to phenylthourea and leprosy.

In a previous study (Hosenfeld and Schröter, 1970) we were able to demonstrate the activity of three serum enzymes, Cholinesterase (EC 3.1.1.8), ceruloplasmin (EC 1.10.3.2.) and alkaline phosphatase (EC 3.1.3.1) as individual characteristics which in healthy adults remain fairly constant for several months. For the purpose of investigating whether these quantitative features are genetically determined, we carried out similar studies on twins.

The twins were traced in the Birth Register of Kiel. A certain amount of selection could have been caused by the willingness to have blood samples taken and by the interest in obtaining Accident Cards. We examined 30 MZ and 30 same-sexed DZ twin pairs, aged 8-20 years. The average age of the two groups of twins was about 15 years. Among the MZ 15 pairs were female; among the DZ, 11 pairs.

Zygosity was established by polysymptomatic comparison of similarity. For documentation, color slides were made. ABO and Rh blood groups of all twins were determined, and in most cases further erythrocytic and serum properties. Blood samples were usually obtained in the afternoon about three to four hours after the last meal. The serum was centrifuged off and frozen. Enzyme determination was carried out during the next one to three weeks. Following substrates were used for estimation of the three enzymes: benzoylcholine, paraphenylendiamine and paranitrophenylphosphate. Acording to the methods of Richterich (1968), all measurements were carried out kinetically, employing a recording spectrophotometer (Beckman DB).

The authors report a case of regional ileitis (Crohn's disease) with an almost identical course in monozygotic twins. Monozygosity is determined by examination of many physical and serological characters.

The Author reports on six subjects of a family (three generations) affected by congenital atresia of the lacrimal canaliculi.

This research compares similarities and differences between kibbutz twins and singletons on individual perceptions of extent of restriction imposed by their fathers and mothers, teachers, caretakers and peers with regard to the children's choices, plans, and actual activities. During the past two years, the parents of all kibbutz twins in Israel of age 1 to 18 have been contacted. They provided background information about themselves and their twin children. In each kibbutz, two control singletons were selected of the same sex and age for each twin pair, yielding a “quartet”. With the aid of a mapping sentence, questionnaires were constructed to help ascertain the child's role in life areas such as family, friendship, school, hobbies, work, amusement. Questionnaires with the same facet design are being administered to children (twin and singleton), mothers, fathers, teachers, and caretakers. In addition, each child is given a battery of tests — including the verbal WISC, Block Design, Raven Matrices, and Reading Comprehension. The children will be interviewed and tested in three successive years, beginning either in grade 4 or 5. Data will thus be obtained on changes in perception of permissiveness-restrictiveness and their relation to performance at ages 9 to 13. To date 9-year-olds in 14 kibbutzim have been interviewed. Analyses of responses to four questions are presented in this paper. The preliminary analyses indicate that twins and singletons have similar means and distributions with regard to the extent to which the children feel they are told what to do by either parent.

The expected correlation between polar body twins depends upon the frequency and distribution of chiasmata occurring during oogenesis. We have estimated the expected values of these correlations using assumptions believed to be biologically valid. The expected value of the overall correlation between first polar body twins is estimated to be 0.38 and that between second polar body twins is estimated to be 0.51. There is little difference between the correlation of DZ twins and that expected for second polar body twins.

The correlation for a specific locus depends upon its distance from the centromere for both types of polar body twins. This effect is especially marked for second polar body twins. For second polar body twins, loci at or near the telomere will have a correlation close to that expected for first polar body twins. It is concluded that only those marker genes that lie at or close to the centromere are appropriate for the detection of polar body twinning.

The genetic roots of speech development in children are being investigated. On the basis of observations in the development of speech in 12 monozygotic twin pairs it could be shown that not only the retarded but also the normal development of speech is an idiotypic characteristic. It must be considered however, that we are not dealing with a simple characteristic, but with the result of a whole complex (intelligence, type of immagination, fine-motor and vitality) of the mentioned root. Further examinations regard the disposition for stammering. On the basis of research with monozygotic twins, of which one partner during the examination presented only signs of cluttering, the other one, however, clonic-tonic stammering, while both twins had a pathologic electroencephalogram, the hereditary basis of speech defects and stammering is shown. However, only in half of the cases of monozygotic twins one can find a disposition for dyslalia, which can be of a very different (periphercentral) nature.

Two DZ monoplacental twins are reported, one affected by mongolism and the other normal. Chromosome examination in the former indicated trisomy 21, while the latter presented a mosaicism consisting, at the age of 13 days, in 70% normal and 30% 21-trisomic cells; at the age of 5 months, in 95% normal and 5% trisomic cells; while, at the age of one year, all the cells appeared to be normal.

The possibility of mosaicism, and, according to clinical and hematological findings, that of feto-fetal blood transfusion are excluded.

The hypothesis is suggested of a progressive loss of the reproductive capacity of « chimaera » of abnormal lymphocytes.

Daunomycin (Da) a metabolite of Streptomyces peucetius has a cytotoxic and antimitotic activity on normal and neoplastic mammalian cells grown in vitro and strongly inhibits a variety of experimental tumors.

The cell damage induced by Da is mainly nuclear.

A finely granular appearance of the chromatin and marked alterations in shape and size of nucleoli in resting cells and many mitotic aberrations in mitotic cells were observed.

Biochemical and autoradiographic researches show that the binding of Da with DNA causes a reduction of the DNA and RNA synthesis, especially of the RNA which is synthesized in the nucleoli and then passes into the cytoplasmic ribosomic RNA.

Treatment with Da on synchronized cells shows a marked drop of the mitotic index and appearance of mitotic anomalies when the cells are treated in S and G2 phases.

This reduction keeps also in the second mitotic wave. A reduction of the mitotic activity is observed also if the cells are treated near the middle of the interphase.

Da causes a reduction in the percentage of the nuclei labelled with 3H thymidine and in the number of grains per nucleus, when the cells are treated in S phase, in the very beginning and middle of interphase.

A survey of the existing literature on the subject reveals that this anatomical variation has been even recently considered as morbid form. All the known information, however incomplete, concerning the shape, frequency, distribution according to sex and age, time of onset and development of the formation, is reported.

Little is known concerning the etiology of this hypertrophy: it has appeared as linked with race groups (Eskimo, American Indians, Mongols) and with family groups.

This appears to be substantiated by the observations — herein reported — made on 12 twin pairs, of which 9 are MZ and 3 are DZ. All nine MZ pairs are concordant as to torus; one of the three DZ pairs is already discordant.

As the concordance of MZ twins for a single trait generally indicates that it is inherited, we can consider tours palatinus as a morphological variation of a hereditary genie trait peculiar of some race — and family — groups.