Base substitutions, length differences and DNA strand asymmetries in the human G gamma and A gamma fetal globin gene region

We have studied differences arising subsequent to the 5 kilobase pair (kb) duplication that led to the human G gamma and A gamma fetal globin genes. The local occurrence of base substitutions in the duplicated 5 kb region correlates positively with the local AT base pair content. This correlation also occurs in two mouse beta-globin genes and in two mouse immunoglobulin genes. The relationship is valid for transcribed or nontranscribed DNA and for DNA that contains only coding sequences. Length differences in the fetal globin duplicated regions correlate positively with the occurrence of short direct repeats of greater than or equal 5 base pairs. Path analysis of the interrelationships of base composition, base substitutions, repeats and length differences provides an integrated view of the relative effects on chromosomal changes of these variables and of selection. The distributions along the chromosome of simple sequences and of base compositions show highly significant local asymmetries between the transcribed and nontranscribed strands of the DNA, which permit us to divide the fetal globin gene region into chromosomal domains. Comparable domains are present in DNA from other sources, including the mammalian viruses SV40 and polyoma virus strain A-2 in which some of the domains appear related to discrete functions.

Mapping and characterization of the hisD-unlinked nif mutants in Klebsiella pneumoniae

Two hisD-unlinked genes NifC5 and NifC7 are mapped in the chromosome of K. pneumoniae. The sequence of NifC5 and NifC7 is suggested as NifC5--gltB--NifC7--argG. The P1 infected E. coli lysate can transduce the mutant C-7 to be Nif+ transductant, yet fails to transduce the hisD-linked nif mutants to be Nif+ ones. This indicates that the gene encoding C-7 is not the structural gene of nitrogen fixation and is present in E. coli. It is actually a gene specifying the glutamate synthetase. SDS electrophoresis shows the marked low content of nitrogen reductase and immunoelectrophoretic test reveals the reduced amount of both nitrogenase and nitrogen reductase in the mutant cells.

Free vascularised bone graft using microvascular technique

The authors investigated 212 dried human fibulae to find out the length, the circumference and the entry points of nutrient artery to the fibula. Angiography of six freshly amputated limbs was studied to show the relationship of the posterior tibial artery and peroneal artery. Seven clinical cases of free vascularised fibula graft are reported. The length of the fibula graft varies from 10 cm to 20 cm. A postoperative 113M-In EDTMP examination revealed the blood supply to the grafted fibula was adequate. The bony healing and functional restoration of the extremities proved to be satisfactory.

Lymphomatoid granulomatosis in a child with acute lymphatic leukemia in remission

Lymphomatoid granulomatosis, a tumor-like process of unknown etiology, produced progressively destructive disease of the larynx, trachea and bronchi in an eight-year-old girl with acute lymphoblastic leukemia of five years duration. The leukemia had been in remission for 4 1/2 years at the clinical onset of the lymphomatoid granulomatosis. Whether this occurrence suggests that lymphomatoid granulomatosis is a type of neoplasm, or is associated with immunologic depression, cannot be stated. Fortunately rare, and of poor prognosis, the disorder may become more frequent with improved survival rate of patients with leukemia and other neoplasms.