Improved preferential tumor hyperthermia with regional heating and systemic blood cooling: a balanced heat transfer method.

Absorption of power in large body volumes can occur with some approaches used for hyperthermia treatment of cancer. A systemic heat absorption rate exceeding the heat dissipation rate can lead to systemic temperature elevation that limits the magnitude and duration of application of power and hence the degree of preferential tumor temperature rise. We describe a hyperthermia approach consisting of regional electromagnetic power absorption and extracorporeal blood cooling with regulation of both systemic heat absorption and dissipation rates ("balanced heat transfer"). A test of this approach in five dogs with nonperfused tumor models demonstrated intratumoral temperatures greater than 42 degrees C, while systemic temperature remained at 33 degrees C and visceral temperatures within the heated region equilibrated between 33 and 42 degrees C. Solutions of the bioheat transfer equation were obtained for a simplified model with a tumor perfusion rate lower than surrounding normal tissue perfusion rate. In this model, the use of arterial blood temperatures less than 37 degrees C allowed higher power densities to be used, for given normal tissue temperatures, than when arterial temperature was greater than or equal to 37 degrees C. As a result, higher intratumoral temperatures were predicted. Control of arterial blood temperature using extracorporeal cooling may thus (1) limit systemic temperature rise produced by regional heating devices and (2) offer a means of improving intratumoral temperature elevations.

Membrane-DNA attachment sites in Streptococcus faecalis cells grown at different rates.

The M-band technique was used to assess the number of attachment points of DNA to the cell membrane of Streptococcus faecalis grown at three different rates. Cells were X irradiated in liquid nitrogen and then analyzed simultaneously for the introduction of double-strand breaks into the chromosome and the degree of removal of DNA from the cell membrane (M band). Consideration of the data from these experiments and of the topology of the bacterial chromosome resulted in a reevaluation of former quantitative models. Our results are consistent with a semiquantitative model in which the bacterial chromosome is organized around a core structure. We interpret our data to mean that the core is attached to the membrane and that the complexity of the core changes more drastically with growth rate than does the number of membrane-DNA attachment points. An alternative model in which RNA hybridizes with DNA containing single- and double-strand breaks is also discussed. In any event, the complexity of these interactions precludes a reliable estimate of the number of membrane-DNA attachment sites.

Growth of Streptococcus mutans protoplasts is not inhibited by penicillin.

A method is described in which cells of Streptococcus mutans BHT can be converted to spherical, osmotically fragile protoplasts. Exponential-phase cells were suspended in a solution containing 0.5 M melezitose, and their cell walls were hydrolyzed with mutanolysin (M-1 enzyme). When the resultant protoplasts were incubated in a chemically defined growth medium containing 0.5 M NH4Cl, the protoplast suspensions increased in turbidity, protein, ribonucleic acid, and deoxyribonucleic acid in a balanced fashion. In the presence of benzylpenicillin (5 microgram/ml), balanced growth of protoplasts was indistinguishable from untreated controls. This absence of inhibition of protoplast growth in the presence of benzylpenicillin was apparently not due to inactivation of the antibiotic. When exponential-phase cells of S. mutans BHT were first exposed to 5 microgram of benzyl-penicillin per ml for 1 h and then converted to protoplasts, these protoplasts were also able to grow in chemically defined, osmotically stabilized medium. The ability of wall-free protoplasts to grow and to synthesize ribonucleic acid and protein in the presence of a relatively high concentration of benzylpenicillin contrasts with the previously reported rapid inhibition of ribonucleic acid and protein synthesis in intact streptococci. These data suggest that this secondary inhibition of ribonucleic acid and protein synthesis in whole cells is due to factors involved with the continued assembly of an intact, insoluble cell wall rather than with earlier stages of peptidoglycan synthesis.

Polymorphonuclear leukocyte function in cancer patients treated with total body hyperthermia.

This study was performed to determine if the ingestive and bactericidal capacity of peripheral blood polymorphonuclear leukocytes (PMN) was altered in cancer patients treated with total body hyperthermia (TBH). TBH of either 41.5 or 42.0 C was induced and maintained for periods up to 6 hours by extracorporeal circulation of the patient's blood through a very sensitive temperature regulating device via a shunt in the patient's leg. In vitro studies performed at 37 C showed that the bactericidal capacity of the PMN from cancer patients was initially generally lower than values obtained from control individuals, but most of the patients' PMN exhibited an increased bactericidal capacity following TBH. Function was not diminished by multiple hyperthermia treatments. Similar studies performed in vitro at 42 C showed that the bactericidal capacity of PMN from both control individuals and cancer patients was significantly less than those obtained at 37 C. These data indicate that the bactericidal capacity of peripheral blood PMN may be transiently increased after TBH, but during the period of elevated temperature, the phagocytic process may be retarded.

Membranes of Rhodopseudomonas sphaeroides. VI. Isolation of a fraction enriched in newly synthesized bacteriochlorophyll alpha-protein complexes.

Radioactivity eventually destined for the chromatophore membrane of Rhodopseudomonas sphaeroides was shown in pulse-chase studies to appear first in a distinct pigmented fraction. The material formed an upper pigmented band which sedimented more slowly than chromatophores when cell-free extracts were subjected directly to rate-zone sedimentation on sucrose density gradients. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the purified fraction contained polypeptide bands of the same mobility as light-harvesting bacteriochlorophyll alpha and reaction center-associated protein components of chromatophores; these were superimposed upon cytoplasmic membrane polypeptides. The pulse-chase relation was confined mainly to the polypeptide components of these pigment-protein complexes. It is suggested that the isolated fraction may be derived from sites at which new membrane invagination is initiated.

Membranes of Rhodopseudomonas sphaeroides. V. Identification of bacteriochlorophyll alpha-depleted cytoplasmic membrane in phototrophically grown cells.

The separation of membrane fragments was investigated in extracts of phototropically grown Rhodopseudomonas sphaeroides to determine if the plasma membrane contains discrete regions. A highly purified fraction of bacteriochlorophyll alpha-deficient membrane fragments was isolated by differential centrifugation, chromatography on Sepharose 2B, reaggregation, and isopycnic sedimentation on sucrose gradients. Significant levels of b- and c-type cytochromes and succinate dehydrogenase were demonstrated in the isolated membrane fragments and their appearance in electron micrographs, their polypeptide profile in dodecyl sulfate-polyacrylamide gel electrophoresis, and overall chemical composition were essentially identical to a similar fraction isolated from aerobically grown cells. Their polypeptide profiles were distinct from those of the intracytoplasmic chromatophore and outer membranes, and on the basis of bacteriochlorophyll content the phototrophic fraction was contaminated with chromatophores by less than 9%. The membrane fragments contained no diaminopimelic acid or glucosamine. It is condluded that the membrane fragments isolated from phototrophically growing Rp. sphaeroides have arisen from photosynthetic pigment-depleted regions of the plasma membrane structurally and functionally differentiated from the intracytoplasmic chromatophore membrane. These regions represent conserved chemotrophic cytoplasmic membrane whose synthesis continues under photoheterotrophic conditions.

Delayed cutaneous hypersensitivity and human renal allotransplantation.

A group of 154 patients on chronic dialysis has been evaluated by DNCB reactivity. Viewed as a group, these patients exhibit a highly significant decrease in immunologic responsiveness in comparison to normal individuals. However, 19% of patients had an immunologic response to DNCB and 12% an irritant response. This pretransplant DNCB responsiveness correlated significantly with subsequent allograft rejection in 71 renal allotransplant recipients. For example, at 1 year after transplantation graft survival was strikingly different: DNCB- patients, 78%; DNCB+ patients, 29%; and DNCB-IR patients; 20%. Pretransplant recall-antigen testing results in 32 patients did not correlate significantly with subsequent transplant results. Serial posttransplant delayed cutaneous hypersensitivity responses in patients with a positive response to a skin test antigen in the pretransplant period suggest possible usefulness of this technique for detecting rejection in the posttransplant period. DNCB skin testing should be performed in all transplant candidates to evaluate host responsiveness and should aid in future patient management.

Rejection and repair of endothelium in major vessel transplants.

Fresh saphenous vein homografts are gaining popularity as conduits for femoral-popliteal or distal bypass grafts. Aside from major blood group compatibility, there is little clinical evidence that rejection is a significant factor in long-term patency. Some have suggested that blood vessels are weakly antigenic and others indicate that rejection does not endanger long-term patency. Transplantation and toxic damage were produced in experimental animals in order to compare healing processes. Both types of injuries produced early significant endothelial cell proliferation detected by H3-thymidine uptake. This response peaked at 5 days in transplants and ever-expanding islands of proliferating endothelium were present in aortas exposed to 20 percent sodium chloride, leading to healing in 3 to 4 months. In the transplanted vessels, total endothelial destruction occurred at 11 to 28 days, and cells of host origin determined by sex chromatin analysis gradually resurfaced those grafts that maintained patency. At 4 months only two of six carotid artery homografts were patent in unmodified dogs, and eight of nine were patent in animals given 1 mg. per kilogram of Imuran. All patent grafts were resurfaced by host cells. We conclude that rejection does play a role in long-term patency; that donor endothelium of living vascular grafts cannot maintain sufficient proliferative capacity to repair immunological damage; that small doses of Imuran significantly alter the rate of destruction leading to more orderly repair and patency; and that clinical trials utilizing one half the dose of Imuran required for kidney graft survival are likely to improve significantly the long-term patency rate of fresh arterial or venous homografts in man.

Delayed hypersensitivity to DNCB and survival following radiation therapy in patients with solid malignant tumors.

Delayed hypersensitivity to dinitrochlorobenzene (DNCB) was tested prior to radiation therapy in 206 patients with solid tumors. The patients were separated into a DNCB-positive group who showed a significant response to DNCB and a DNCB-negative group who did not. After one year, it was found that patients with a positive DNCB reaction had a statistically better chance of survival than those with a negative DNCB reaction. Although this is not proof that DNCB testing can indicate those patients who should be excluded from radical therapy, it can help identify those who may respond favorably to extended efforts at palliation or cure despite clinically advanced disease.

Alpha Fetoprotein: An index of progression or regression of hepatoma, and a target for immunotherapy.

CLINICAL AND LABORATORY STUDIES OF AFP PRODUCING HEPATOMAS DEMONSTRATED THAT: 1) serum AFP levels correlated directly with tumor growth; 2) circulating AFP could be cleared by passive administration of an. excess of anti-AFP; and 3) highly specific anti-AFP functioned as a carrier to localize diagnostic and possibly therapeutic amounts of radioactivity in hepatoma tissue. These studies helped elucidate certain criteria which should be fulfilled before attempts to initiate passive humoral immunotherapy of cancer are undertaken.