Reliability of chemical tests for fecal occult blood in hospitalized patients

In 39 hospitalized patients with suspected gastrointestinal bleeding and given intravenous 51Cr-labeled red cells, reactions of three chemical spot tests for fecal occult blood were compared with the "true" blood loss as determined by stool radioassay. Guaiac reagent and orthotolidine (Hematest) tablets were extremely sensitive, but yielded false-positive reaction rates of 72% and 76%, respectively on the 240 stool specimens compared. A modified guaiac test (Hemoccult) exhibited a false positive rate of 12%. Of the 27 patients entering the study due to positive guaiac or Hematest screening tests, 17 (63%) were not bleeding. Hemoccult, approximately 1/4 as sensitive as guaiac and Hematest, could miss lesions with low rates of bleeding unless multiple stools were tested. While barium had no effect, iron therapy or laxatives tended to lower both false-positive and false-negative reactions for all reagents. A positive Hemoccult test usually indicated significant gastrointestinal bleeding and would appear to be the test of choice provided at least 3 stools are tested to minimize false-negative results.

The extrinsic blood vessels of the ovary of the sheep

The extrinsic ovarian blood vessels were studied in 134 ewes. In view of recent evidence that uterine luteolysis may involve venoarterial transfer of prostaglandin F2alpha in the ovarian pedicle, particular attention was paid to the interrelationships between veins and arteries. The ovarian artery and utero-ovarian vein are large vessels of conventional structure and lie in close apposition. Their walls are slightly thinner on their apposing sides. The ovarian branches of the ovarian artery are very tortuous, and closely intertwined with the plexiform ovarian branches of the utero-ovarian vein. An extensive plexus of small veins surrounds the ovarian artery and its ovarian branches. Within this plexus are many thin-walled, dilated regions, interspersed with narrow, thick-walled segments. Valves are inconstantly present at sites of entry of branches of the plexus into the major veins. Small numbers of arterio-venous anastomoses are present in the distal part of the ovarian pedicle. Unless blood can flow in a veno-arterial direction through arterio-venous anastomoses or capillary beds, the structural barrier between uterine venous and ovarian arterial blood is substantial.

The identification and ultrastructure of macrophages from the mammary gland of the ewe

Cells in the secretion of involuting and non-lactating mammary glands of the ewe were studied. Light microscopy studies revealed that the majority of the cells were mononucleated, but it was impossible to distinguish macrophages from sloughed epithelial cells. Electron microscopy studies showed that the majority of the cells were macrophages and that they phagocytosed polystyrene latex spheres. Very few epithelial cells were found and they were distinguished from macrophages by numerous microfilaments and blunt microvilli. Epithelial cells could be further distinguished from macrophages by the presence of tight junctions. Tissue cultures of cells in secretion of mammary glands revealed the predominant cell type to be the macrophage. After 3 days in culture these macrophages formed multinucleated giant cells which contained acid-phosphatase granules. Fluorescein-labelled antiserum prepared against the cell cultures, stained cells in the lumens of alveoli and ducts, but not epithelial cells, in frozen sections of mammary tissue. The study confirms previous findings that the large majority of cells from mammary glands in late involution are macrophages. It also points to the usefulness of non-lactating mammary glands as a source of sheep and cattle macrophages.

[Normal prenatal growth of the golden hamster (author's transl)]

In the golden hamster (Mesocricetus auratus) the gestation period and the loculus size of the gravid uterus from day 6 to day 15.5 (parturition) of gestation as well as the weight, width (umbilcus-black) and lenght (crown-rump) of the embryos from day 9 to the parturition were measured. The results obtained were as follows: 1. The gestation period of the golden hamster was 15 days and 15 +/- 3 hours post coitum. 2. The average values of the length (in the direction of uterine long axis) and width (mesome-trial-antimesometrial axis) in the loculus of the gravid uterus were 0.39 cm and 0.56 cm at 6 days, and 2.42 cm and 1.74 cm at 15.5 days (partiurition), respectively. 3. The average values of the crown-rump measurements, width (umblicus-back) and weight in the hamster embryos were 0.42 cm, 0.24 cm and 0.026 g at 9 days, and 2.40 cm, 1.39 cm and 2.272 g at 15.5 days (parturition), respectively. 4. The loculus size of the gravid uterus, the crown-rump measurements and width (umblicus-back) of the embryos in the period from day 13 to day 14 of gestation were markedly increased in comparison with any other period, and the weight increase of the embryos occurred rapidly from day 13 of gestation. 5. The shape of the loculus during the gestation was ovoid (mesometrial-antimesometrial axis) until the end of 10 days converged to the spherical form and thereafter changed gradually to the ovoid from in the direction of uterine long axis contraly to the previous days.

A possible role of repetitious DNA in recombinatory joining during chromosome rearrangement in Drosophila melanogaster

It is postulated that certain repetitious DNA components play a role in the recombination processes during chromoxome reappangements. When the distribution of silver grain densities after the in situ hybridization of repetitious DNA (RUDKIN and TARTOF 1973) and the distribution of chromosome breaks due to X-irradiation (KAUFMANN 1946) are compared, a strong correlation is found for the euchromatic portion of the D. melanogaster salivary X chromosome. These observations justify the postulate above that certain repetitious DNA provides homologous regions in the DNA of broken chromosome ends necessary for proper recombinatory joining.

Heterochromatic chromosomes and satellite DNAs of Drosophila nasutoides

Drosophila nasutoides is distinguished from other Drosophila species in that the metaphase karyotype shows a pair of very large V-shaped chromosomes. With Giemsa, a distinctive C-banding pattern is revealed along the arms of this large chromosome, indicating a largely heterochromatic nature. Furthermore, the banding patterns of the arms are symmetrical, indicating that it is an iso-chromosome. A comparison between the metaphase karyotype and polytene chromosomes suggests that the large V chromosome appears as the dot chromosome in polytene squash. One autosome has twice the arm length of typical Drosophila polytene chromosomes and arose either by centric fusion and a pericentric inversion, or by translocation connecting distal ends with a subsequent loss of one centromere. This chromosome appears to have a short arm which ectopically pairs with the proximal region of the long arm, representing a duplication of about ten bands. When the nuclear DNA is examined by neutral CsCl gradient, four satellites are observed. As much as sixty percent of the total DNA appears as satellites in the lysate of larval brains. No satellite was detectable in the lysate of salivary glands. These observations led us to suggest that the heterochromatic nature of the large V chromosome is due to the presence of all four satellites in this chromosome and that this large chromosome appears as the dot because of the under-reduplication of the satellites during polytenization.

Renal transplantation in diabetes mellitus in rats

Immunoglobulins and complement are deposited in the glomerular mesangium of rats with progressive glomerulosclerosis secondary to chemically induced diabetes mellitus. Isotransplantation of a kidney from a rat diabetic for 6 mo into a normal recipient results within 2 mo in the disappearance of IgG, IgM, and beta(1)C from the mesangium and arrest or reversal of the light microscopic glomerular lesions. Kidneys isotransplanted from normal donors into diabetic rats developed mesangial matrix thickening and deposition of IgG, IgM) and beta(1)C in the mesangium. No glomerular changes occur upon transplantation of a normal kidney into a normal rat. These findings indicate that diabetic glomerular changes in the rat are reversible and are secondary to the diabetic state rather than to the inducing agent.

Position of the Duffy locus on chromosome 1 in relation to breakpoints for structural rearrangements

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