Origins of hemopoietic and stromal cells in subcutaneous femur implants

The origin of spleen colony-forming units (CFUs) and fibroblastoid colony-forming cells (CFUF) repopulating the marrow of femurs subcutaneously implanted in syngeneic and semi-syngeneic mice was studied by making use of a chromosome marker for CFUs and a cytotoxicity test for CFUF. The CFUs present in implants during first 4 weeks were of a mixture of those from the donor and the host, and thereafter, were exclusively of host origin. On the other hand, the colony growth of CFUF from the marrow of C57BL/6 femurs grafted in B6CBAF1 mice remained almost totally unaffected by treatment with C57BL/6 anti-B6CBAF1 serum as late as 40 weeks after implantation. Quite similar results were obtained from the marrow-depleted femur implants. It is concluded from the present studies that chimeric marrow consisting of hemopoietic cells of host origin and stromal cells of donor origin can repopulate the femurs within a matter of several weeks after subcutaneous implantation.

[Clinical evaluation of amikacin in severe infections with hematological malignant diseases (author's transl)]

Investigation was made on absorption, excretion and clinical responses following intravenous drip infusion of amikacin (AMK) and the following results were obtained. 1) Serum concentrations of AMK were determined after completion of a 1 hour-course of its intravenous drip infusion at a dose of 200 mg, involving 2 patients with normal renal function and 1 patient with impaired renal function. In the patients with normal renal function, a mean peak serum concentration of 15.9 micrograms/ml was reached at the termination of the intravenous drip infusion and, then, gradually declined to 0.97 microgram/ml at 6 hours after completion of the intravenous drip infusion. The half-lives were 1.64 and 1.41 hours, respectively. In the patients with impaired renal function, the elimination of AMK from blood flow was markedly delayed and the serum concentration was 5.52 micrograms/ml even at 6 hours after completion of the intravenous drip infusion. The half-life was prolonged, its value being 5.98 hours. 2) The mean urinary excretion rate for the patients with normal renal function was 67.7% within 7 hours, while the patient with impaired renal function had a lower rate of 14.0%. 3) Ten infectious patients with hematological malignant diseases were treated with AMK intravenous drip infusion. Clinical responses were excellent in 6, good in 2, fair in 1 and poor in 1. Thus, 80% of the patients responded to AMK. 4) In order to check the side effects of AMK, investigation was made on the results of various clinical laboratory tests and the subjective and objective findings. But, no side effects attributed to AMK were observed. Therefore, it is thought that the intravenous drip infusion of AMK will be very useful when attention is paid to infusion time, dose and interval.

Studies on graft versus host (GvH) reactions. I. Impairment of hemopoietic stroma in mice suffering from GvH disease

The hematologic changes were described in the adult (C57BL/6 x C3H/He) F1 hybrid mice suffering from graft versus host (GvH) disease induced with 10(8) parental (C3H/He) lymph node (PLN) cells. Progressive decreased in numbers of leucocytes, granulocytes, erythrocytes and reticulocytes was observed from day 7 to 14 of GvH disease. Thrombocytopenia was not so remarkable. A histologic study revealed and extremely hypoplastic marrow. The number of colony forming units (CFUs)/femur decreased progressively from day 5 to 14. When the femurs, removed from the diseased mice at various intervals after the PLN cell injection, were implanted subcutaneously into other hosts for 7 weeks in order to evaluate the hemopoietic stroma to support the hemopoietic stem cells, the progressive decrease in CFUs number in the implanted femurs was also observed from day 5 to 14. There was a dose relation between the number of PLN cells injected and the reduction of CFUs number either in the femurs in situ or the implanted femurs. It is thus concluded that the impairment of hemopoietic stroma results form F1 hybrid disease, i.e., GvH disease and can be one of the major causes of the depletion of hemopoietic cells resulting in pancytopenia.

Age-related changes in the function of hemopoietic stroma in mice

Hemopoietic function of the marrow and splenic stroma in C57BL/6 mice aging from 2 to 24 months were evaluated with the use of subcutaneous implantation method. Although there was no significant difference in the concentration as well as the total number of CFU(S) in femoral marrows between aged and young mice, the rates of CFU(S) repopulation in the femoral marrows from aged donors were significantly lower than in those from young donors when grafted subcutaneously in the 2 month-old syngeneic hosts. On the other hand, the femoral marrow grafts from 2 month-old donors were constantly repopulated irrespective of the age of the hosts. An essentially similar finding was obtained in the study of spleen grafts. It is suggested that the defective hemopoiesis, if any, in aged mice is primarily caused by the changes in hemopoietic stroma rather than those in hemopoietic stem cells.

Protection of mice against virulent virus infection by a temperature-sensitive mutant derived from an HVJ (Sendai virus) carrier culture

Experimental infection with HVJ (haemagglutinating virus of Japan-the Sendai strain of parainfluenza 1 virus) in mice was studied. Aerosol infection of newborn mice with the wild-type virus (HVJ-W) retarded the development of body weight and killed the animals within a few weeks. Large amounts of virus were isolated from both the lungs and the nasal turbinates of infected mice. In contrast, newborn mice exposed by inhalation to a temperature-sensitive (ts) mutant (HVJ-pB) derived from an HVJ carrier culture showed no clinical signs and grew equally well as mock-infected animals. No infectious virus could be recovered from the lungs although the ts mutant grew to moderate titre in the nasal turbinates. The prior inoculation of newborn mice with the ts mutant virus induced a state of significant resistance to subsequent challenge with the virulent wild-type virus. No replication of challenge virus in both lungs and nasal turbinates could be detected and the animals were protected a lethal infection. It is suggested that an avirulent temperature-sensitive mutant which has lost the capacity to replicate in the lower respiratory tract but is still capable of multiplying in the nasal turbinates may be a promising candidate for use in live vaccines especially against the infectious disease of the lower respiratory tract.