Cerebral NMR imaging: early results with a 0.12 T resistive system

Over a 6-month period, 157 patients, 89 of whom had central nervous system tumors, were examined on a prototype 0.12 T resistive nuclear magnetic resonance (NMR) imaging unit. All of the patients had computed tomography (CT), which was used as a standard to which the NMR findings were compared. Studies were done primarily by saturation-recovery technique with short repetition times. The signal intensity with saturation-recovery technique did not allow differentiation among most tumor types. Location, extent, and morphology helped to some extent in attempts at differentiation. In the multiplanar mode, NMR compared favorably to CT with regard to lesion detection. Limited early experience suggests that NMR also may detect some lesions when the CT is negative and may detect additional lesions when one or more are present. The NMR examination was well tolerated by selected patients.

Retroconversion of malignant immature teratomas of the ovary after chemotherapy

Two cases are reported in which a malignant, immature teratoma of the ovary retroconverted to a benign mature teratoma following chemotherapy. The literature is reviewed and possible explanations for this phenomenon are discussed.

A regional network review of health care delivery to children and adolescents with end-stage renal disease

A detailed survey of dialysis facilities in Texas (ESRD Network No. 11) evaluated the health care delivery to all ESRD patients under 21 year of age. 38 units reported data on 115 patients (50 males, 65 females) ranging in age from 7 months to 20 years. Home peritoneal dialysis was used in 20% of the patients with the rest treated by in-center hemodialysis. 50% of the patients were active transplant candidates at the time of survey; of the remaining 58 patients, there were medical reasons for the nontransplant status of 33 but 25 patients elected to stay on dialysis in the absence of medical contraindications to transplant. The units provided excellent support for the psychosocial, educational, nutritional and growth needs of the children and adolescents surveyed.

Growth characteristics of MOPC-315 plasmacytoma and response to anticancer agents

We examined the growth characteristics and response to anticancer agents of the murine plasmacytoma MOPC-315, a rapidly growing and widely disseminating tumor syngeneic in BALB/c mice. The doubling time for the tumor was approximately 24 hours, and about 1 in 100 cells was tumorigenic. We developed a spleen colony assay for the clonogenic component of the tumor and used it to define the dose-response relationships for various anticancer agents, including melphalan, cyclophosphamide, 1,3-bis(chloroethyl)-1-nitrosourea, 5-fluouracil, gamma-radiation, methotrexate, methylprednisolone, cytosine arabinoside, and vincristine.

Growth and rejection of leukemia cells in individual mice after combined treatment with amphotericin B and 1,3-bis(2-chloroethyl)-1-nitrosourea

We assayed the femoral marrows of individual AKR mice for leukemia colony-units (LCFU) after treatment with amphotericin B (AmB) and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) or with BCNU alone. No differences between the groups were noted in the first 7 days after treatment. All the mice treated with BCNU alone were dead by day 8, and all the survivors among the animals receiving AmB and BCNU retained high levels of LCFU for 2 more days; these LCFU were subsequently rejected by the host. By day 12, LCFU were undetectable. Histologic examination of organs from the same mice on day 5 showed fewer leukemia cells in the mice treated with the combination of agents. In all treatment groups, mice dying of leukemia early (by day 9) had systemic leukemia and most had central nervous system (CNS) involvement. All animals dying between days 10 and 14 had CNS leukemia, but few had systemic leukemia; at later times, though few animals died, they invariably had CNS leukemia without systemic involvement.

Evaluation of three dry-sterilized hollow fiber artifical kidneys

We investigated three new dry sterilized hollow fiber artificial kidneys (HFAK) (Cordis Dow CDAK 1.3, Travenol CF 1200, Extracorporeal Tri-Ex 1). Dry sterilization makes these dialyzers more economical by shortening set-up time. Dry sterilization also eliminates iatrogenic administration of residual sterilant. Water of imbibition can significantly increase the blood compartment volume of the dialyzer during dialysis. Consequently, a corrected blood volume for each dialyzer was established; these corrected volumes varied from 13--36% greater than the volume determined before dialysate flow. With low dose heparinization of these dialyzers there was between an 18 and 45% decrease in the post dialysis volume, presumably due to fiber clotting during dialysis. This volume added to the residual blood loss measured by a colorimetric technique accounted for a possible blood loss ranging between 26.9 and 53.9 ml per dialysis for these three dialyzers. Our results suggest that a relationship between dialyzer clotting and decreased dialyzer efficiency may exist. These three capillary flow dialyzers had a much lower platelet drop (0--9% pre to post) when compared to 30--40% drop of flat plate dialyzers. These dialyzers were found to be safe and easy to use but the high fiber clotting warrants further investigation in chronic dialysis patients on high dose heparin.

Protective effects of amphotericin B against spontaneous and transplantable murine tumors

Two tumor systems were used to test prophylactic effects of amphotericin B (AmB). When 0.5 mg AmB was given ip every 2 weeks to AKR mice beginning at 8 weeks of age, the 50% tumor incidence for spontaneous lymphoma development was delayed 2-3 months. In the second tumor system, BALB/c mice received injections of either 20 or 50 mug AmB before receiving MOPC-315-C cells sc. The mice given the low dose of AmB demonstrated a decreased tumor incidence and a reduced tumor growth rate, when compared with controls. Opposite effects were found for the group administered the high dose; tumor incidence and rate of growth were increased.

Synchronized high speed scanning infrared spectrometer

A spectrometer which scans a wavelength band of 0.6 micro in 30 microsec and is useful from 2-6 micro is described. The instrument can be synchronized with a pulsed source with a minimum triggering delay of 15microsec. The instrument is basically an Ebert spectrometer equipped with an indium antimonide detector at the exit slit, an aluminum scanning mirror placed 5 cm before the exit slit, and a wavelength calibration signal generator. The scanning mirror, which is supported on pivots inside a helical coil, deflects the spectrum through an angle of approximately 90 degrees onto the exit slit. When a capacitor is discharged through the coil, the resulting magnetic field spins the aluminum mirror causing the spectrum to move across the exit slit. The wavelength calibration signal generator produces a series of electrical pulses as the scanning mirror turns, permitting wavelength calibration when the pulses are displayed below the spectrometer signal on a dual beam oscilloscope. Using this instrument on a shock tube, data have bee obtained on the absolute spectral radiation intensity of air, nitrogen, neon, and argon heated by reflected shocks to equilibrium temperatures in the range of 6000 degrees K to 10,000 degrees K. In this temperature region with these gases, an important source of continuum radiation is neutral Bremsstrahlung caused by the inelastic scattering of electrons from neutral atoms and molecules. By employing the scanning ir spectrometer it has been possible to separate the continuum radiation from contributions owing to lines and bands and determine the cross section for the neutral Bremsstrahlung.