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This study reports the influence of acute starvation on spontaneous and cyclophosphamide (CP) induced micronucleus (MN) frequencies in the bone marrow polychromatic erythrocytes (PCE) of CD-1 mice. Groups of mice (5/sex) were deprived of either food alone or food and water for 0, 24, 48 and 72 h prior to sacrifice. Although there was no evidence of a significant increase in MN-PCE frequencies among the starved groups, a significant depressant effect of starvation on erythropoietic activity was observed. Peak levels of CP-induced (40 mg/kg b.w.) MN-PCE's appeared later in male mice deprived of food and water after treatment compared to mice given food and water ad libitum. The results indicate that starvation is detrimental to bone marrow erythropoiesis and that starvation may alter the response of mice to clastogens.

This report presents the cytogenetic findings in bone marrow cells of rats exposed to styrene vapor. Male and female Sprague-Dawley rats were exposed to 0, 600 and 1000 ppm of styrene vapor by inhalation 6 hr per day, 5 days a week, for a period of one yr. Blind scoring of metaphase spreads prepared from bone marrow cells collected at the end of the last exposure revealed that neither the 600 ppm nor the 1000 ppm exposures to styrene vapor produced an incidence of chromosomal anomalies higher than those occurring spontaneously. It is interpreted that styrene is non-clastogenic within the present exposure regimen.

Cytological studies have been presented from a 15-year-old girl with short stature and failure of puberty. Buccal mucosa preparations revealed X-chromatin mass approximately double in size of that of a normal female. Leukocyte metaphases suggested a two cell line composition of the patient. One population of cells conformed with 45,X chromosome distribution. The chromosome complement of her other cell line had a modal number of 46. In this cell line a "C" chromosome was replaced by an exceptionally large submetacentric chromosome. This abnormal element exhibited late DNA replicating pattern. G-banding study revealed that the abnormal chromosome was produced as a result of fusion involving telomeric ends of long arms of 2 intact X chromosomes. This translocation X was bearing 2 C-banded areas; one around the centromere and the other at the distal end of the long arm. The distal C-band area did not show any evidence for centromeric function. It appears that a centromere becomes latent in the presence of another centromere in a translocation bearing 2 total chromosomes. Such a change of state in the additional centromere is vital for the stability of the translocation chromosome.

The sex chromosomes of the opossum, Didelphys virginiana, are the only elements that exhibit C-banding. In contrast, the sex chromosomes as well as the autosomes bear specific G-Bands. However, unlike other mammalian species different types of G-banding are observed if the chromosomes are pretreated with trypsin and SSC solution. The SSC pretreated chromosomes show discrete bands only when stained with Giemsa at certain pH values. An asynchronous pattern of terminal DNA replication is observed among the three C-banding regions of the X-chromosome. The inter- and intrapositive G-banding areas of the chromosomes are not always late in DNA replication in comparison to those negatively stained G-banding areas.

Peripheral blood samples from Sprague-Dawley rats gave successful lymphocyte growth in GIBCO: 1A, RPMI 1640, and Eagle's minimum essential medium (MEM) culture media. Various growth conditions, cytokinetics, and sister chromatic exchange (SCE) induction were studied using reconstituted GIBCO 1A only. Neither methoxyflurane anesthesia of the rats before sampling nor washing of the cells with phosphate buffered saline affected the mitotic index. Cultures treated with [3H]thymidine showed the lymphocytes entering into DNA synthesis after approximately 24 h. The time at which BUdR (5-bromo-2' deoxyuridine) was added, i.e. 0 vs. 24 h incubation, had minimal effect on the mitotic index of cultures harvested at 48 h. However, when harvest was extended to 72 h, mitotic activity was greater in the cultures treated with BUdR at 24 h. No significant differences in mitotic index and the number of average lymphocyte division were detected in cultures exposed to 0.3 to 0.5 microgram/ml BUdR at 24 h and harvested at 72 h. Although SCE frequencies increased in the presence of BUdR, the baseline level of SCEs was estimated to be 5 to 6/cell. Average generation time of the lymphocytes dividing between 48 and 72 h was 16.5 h. Because of its simplicity of culture and the reproducible nature of its in vitro growth kinetics, the Sprague-Dawley rat lymphocyte is a suitable model for cytogenetic investigations.

Peripheral blood samples from 17 apparently healthy male volunteers were set up in duplicate cultures using three commercially available media: Eagle's MEM, RPMI 1640, and TC 199. BUdR (5-bromo,2-deoxyuridine) (10 μg/mL) was added to one of the cultures from each person in each medium after 24 h of culture initiation. All cultures were harvested at 72 h of incubation in the presence of colcemid. RPMI 1640 stimulated the highest mitotic activity in both BUdR-treated and untreated cultures. Higher numbers of first division metaphases corresponded with the higher frequency of chromosome-type aberrations in cultures with Eagle's MEM as compared with RPMI 1640 media. On the other hand, higher numbers of chromatid-type aberrations were present in cultures with TC 199 as compared with those with Eagle's MEM. When the chromosome- and chromatid-type aberration data were pooled to score total cytogenetic abnormalities, an influence of the medium was demonstrable. While cultures with Eagle's MEM and TC 199 had the greater number of first division cells, third of subsequent division cells were most prevalent in RPMI 1640 cultures. It is inferred that the length of the cell cycle, the mitotic index, and to some degree the incidence of spontaneous cytogenetic abnormalities are variable attributes of culture media.

High doses of a test chemical sometimes affect the food consumption of the treated animals even to the point of starvation. The effect of such a non-specific toxicological stress on the bone marrow micronucleus test was investigated in male and female Sprague-Dawley rats. A 42-h starvation had a noticeable effect on the ratio of polychromatic to normochromatic erythrocytes (PCE and NCE); the values in the starved animals were approx. 77% of the negative controls. An effect of starvation on the frequency of micronucleated erythrocytes (MN-E) was not discernable from the results of the present experiment.

Peripheral blood cultures were set up from male rats and humans in TC199, RPMI 1640, and minimal essential medium in the presence of 5-bromo,2-deoxyuridine and harvested at 48, 72, and 96 h. Mitotic indices were compared in the different media at all three harvest times, but cytokinetic patterns and baseline sister chromatid exchange (SCE) frequencies were evaluated exclusively in the 72- and 96-h cultures. In general, lymphocyte division kinetics, as determined by average lymphocyte division (ALD) numbers, were comparable between rat and human lymphocytes cultured in any of the three media and harvested at either of the culture times. The numbers of SCEs were distributed between and within the two systems independent of ALD numbers or the harvest time. Overall, no influence of media was detected on the distribution of SCEs. Despite a number of similarities in growth characteristics between rat and human lymphocytes, the rat lymphocyte test system has distinct advantages over that of the human because of the easy access to rat blood samples and the absence of the many restrictions applicable to humans.

Although waste stabilization ponds have been well known for centuries, in the last 30 years there has been rapid progress in the use of these ponds as a waste treatment alternative under varying organic and hydraulic loading conditions. The fundamental bio-geochemical relationships existing within the ponds have been an interesting field of research. The design of these ponds has been based on empirical formulations with utter disregard for some very pertinent functional parameters. In the present study on model G.I. aquaria, emphasis is put on the consideration of these ponds as a micro-aquatic engineered ecosystem and the likely changes in water quality affected by these interrelationships throughout a 24-hour cycle. The dependence of these ponds on solar energy and symbiotic algal-bacterial activity for efficient waste treatment in this era of energy crisis is borne out by the increase in gross production to the tune of 10 times, in dissolved oxygen of more than 2.5 times, and in pH by nearly 1.4 units during one single day.

Bone marrow smears from Fischer-344 rats possessed such a high incidence of basophilic granules that accurate detection of micronucleated erythrocytes was not possible. In contrast, preparations from Sprague-Dawley rats had far fewer such granules, so that the micronucleated marrow cells were clearly visualized and counted. The difference in the incidence of basophilic granules was attributed to strain differences in mast cell population size.

In vitro cytogenetic assays are widely conducted to assess the mutagenic potential of chemicals. Chinese hamster ovary (CHO) cells or human lymphocytes are often used for these assays; however, these cell types have certain limitations. In order to evaluate an alternate cell system, cultured rat lymphocytes were treated for 4 h at 48 h of incubation with a variety of direct- and indirect-acting clastogens in the presence or absence of an exogenous mammalian activation system. Cytogenetic effects of in vitro physiological alterations such as medium hypertonicity or pH changes were also evaluated. The background aberration rate of rat lymphocytes is approximately 2%, and they respond positively to both direct- and indirect-acting clastogens. In contrast to CHO cells, however, neither the hyperosmolality nor pH changes in the treatment media have significant effect on background aberrations. Unlike samples of human blood, rat blood can be collected under well-controlled environmental conditions. Because of the easy access to rat blood samples, the simplicity of culture, the reproducible nature of its in vitro growth, the positive response to known clastogens and negative response to media pH changes or hyperosmolalities, the rat lymphocyte in vitro chromosomal assay presented is an optimal system to assess the mutagenic potential of chemicals.

Forty patients with unequivocal Turner stigmata and cardiovascular disease were studied. Every patient had complete documentation of both his cardiovascular disease and chromosomal constitution by physical examination, electrocardiogram, roentgenogram and cardiac catheterization, chromosome preparation and buccal mucosal smear. Two clusters of cardiovascular lesions were observed. Coarctation of the aorta occurred in 11 of 16 patients with XO Turner syndrome but not in any of the patients with Turner phenotype or Turner mosaic constitution. Pulmonic stenosis was present in 21 of 24 patients with Turner phenotype and Turner mosaic constitution but was not encountered in those with XO Turner syndrome.

One of the female members of a family with hereditary D/D-translocation chromosome was found to be mosaic for two major cell lines. One of her cell lines was consistent with balanced D/D-translocation, i.e., 45, XX, D–D–, t (DqDq). Her other cell line had each cell with 46chromosomes. In these cells, however, a normal D-chromosome was replaced by a telocentric ‘marker’ chromosome with comparable size of the long arm of a D-chromosome. The mosaic carrier has transmitted this ‘marker’ chromosome to her son. It is interpreted that during the embryonic life of the female carrier, one of the cells with the translocation D/D-chromosome underwent centric misdivision that was followed by a pericentric inversion in one of the telocentrics. These two processes apparently gave to a stable telocentric D-chromosome and a regular D-group chromosome.

Despite the fact that HeLa and HEp-2 cell lines have been established respectively from a female and a male patient, the frequent loss of the Y chromosome makes it difficult to discriminate the two cell types. The technique of centromeric localization of heterochromatin, however, facilitates more definite identification of the two cell types. Giemsa positive centromeric constitutive heterochromatin blocks were induced within the intact metaphase chromosome preparations of Hela and HEp-2 cells. The Hela cell population had a single heterochromatin marker chromosome, whereas the HEp-2 cell line was found to possess two types of heterochromatin markers. The distinctive patterns of distribution of constitutive heterochromatin of these three chromosomes served as the guides in tracing the presumptive cytological pathways for their orgin.

2 male patients with G-trisomic Down's syndrome, were studied for constitutive heterochromatin pattern by the technique of Arrighi and Hsu (1971). 2 G-chromosomes were found to have heterochromatin distributed around the centromeric areas and the remaining 3 were free of such localized heterochromatin blocks; the extra G-chromosome belonging to the non-localized heterochromatin members.

The C and G bandings were induced in eight selected human complements with D, G and Y chromosomal aberrations. In a few cases, the Q banding was utilized for additional information. Some of the Robert

Autoradiographic studies on chromosome duplication in cultured mammalian cells (have revealed several very significant findings, including the detection of asyncronous DNA replication in homologous X-chromosomes. In cultured cells froin ,a female Chinese hamster, Taylor (1960) observed that the short arm of one of the X-chromosomes terminates duplication during the first half of the D N A synthetic period, but rhe long arm of the same X-chromosome and the entire portion of the other X-chromosome duplicates only in rhe later part of the D N A synthetic period. A somewhat similar type of out-ofphase D N A replication has also been observed very clearly in presumptive X-chromoson~es in cultured human cells (Ailorishima et nl., 1962; German, 1962; Rowley et nl., 1963). In cultured cells from normal females as well as in diploid polysomic-X cells only one X-chromosome conlpletes its replication along with the autosomes, while the remaining X-chromosome or chromosomes continue their replication after rhe rest of the conlpleillent has terminated duplication. Although the morphologic identification of the X-chron~osomes in Chinese hamster cells is conlparatively easy, it is not so for human X-chromosoines. Since no late-replicating chromosome in group 6-12 + X is seen in normal males as it is in normal females, such late-replicating chron~osomes are considered to be X-chromosomes. T,he sex cl~romarin lnasses found in interphase nuclei with lnore than one X-~hromosome are thought to be forined b) the heteropycnosis of the Xchromosomes (Ohno et nl., 1959), and it is further believed that the heteropycnotic-X-chronlosonles are the ones which complete their D N A replication later than all other chromoson~es in the colnplement (Grumbach et nl., 1963; Atkins et nl., 1962). In general, the number of late-labelling X-chroinosornes observed has been equal to the maximum number of sex chromatin masses present in inter~hase nuclei and one less than the number of X-chroi~losomes in the L diploid complement. Based on the evidence from mouse genetics, Lyon (1961) has postulated that the heteropycnotic X-chroil~osome found in normal mammalian females is genetically inactive, and this ll~ypothesis is supported by cytological observations in cells with an X-autosome translocation in mice (Ohno and Cattanach, 1962) as well as by less direct evidence of glucose-6 phosplhate dehydrogenase activity in inan (Beutler et al., 1962). Pooling all the available information, it appears now that the X-chromosome which forms the sex chromatin mass in interphase nuclei, the heteropycnotic-X, the latereplicating-X and the inactive X are indeed the different manifestations of the same X-chromosome. In mammalian chromosome comuleinents. the X-chromosomes are not rhe I , only ones which show a definite Dattern of D N A re~lication. The autosomes I I and the Y-chromosome also appear to follow a ,definite time and morphologic sequence, and even homologous autosomes may show characteristically differ

Recent genetic, cytogenetic, and clinical findings of the Ullrich-Noonan syndrome have been reviewed in the context of a personal series of 81 patients, the majority of whom were found in 23 families. Direct transmission of all familial cases strongly supports the proposed autosomal dominant mode of inheritance. Cytogenetic evaluation, including utilization of Q and G banding techniques, has failed to disclose a chromosomal anomaly. Diagnostic criteria, frequency of anomalies, and disabilities are presented together with cardiovascular abnormalities and recurrence risks.

The techniques of H3-thymidine autoradiography, C and G bandings were utilized for the identification of an extra “C” chromosome in a patient with 47,XX,+C complement. The abnormal element was found to be an additional homolog of 8 pair. The clinical findings of this patient were compared with those cases that have been reported in the literature as 8 trisomies. A few more such cases must be studied before trisomy 8 syndrome can be established.

The cytological DNA denaturation-reassociation technique has revealed exclusive localization of C-bands within the sex chromosomes of the opossum, Didelphys virginiana .

MOST of the phenotypic characteristics of what is now called Turner's syndrome were first described by Ullrich, 1 in 1930, in an 8-year-old girl. Webbing of the neck, cubitus valgus, congenital lymphangiectatic edema, prominent ears, small mandible, ptosis, dystrophy of the nails, and hypoplastic nipples were among the physical findings he reported. In 1949, Ullrich 2 summarized two decades of observations on such patients and noted that there was a 4:1 preponderance of females over males who presented with these clinical features. Other observers, such as Bizarro 3 had also recorded the presence of this syndrome in males. Several years after Ullrich's original report, Turner, 4 in 1938, specified certain features in older patients, all of whom were females, which are considered by some to be the cardinal signs of Turner's syndrome: webbed neck, cubitus valgus, and sexual infantilism. The sexual infantilism had not been apparent to Ullrich, whose patients