The effect of temperature on the performance and stability of thermophilic anaerobic digestion.

Sustainable operation of an anaerobic sewage sludge digester requires the effective shuttling of carbon from complex organic material to methane gas. The accumulation of intermediates and metabolic products such as volatile fatty acids and hydrogen gas not only reveal inefficiency within the digestion process, but can be detrimental to reactor operation at sufficiently high levels. Eight anaerobic digesters (1 mesophilic and 7 thermophilic) were operated in order to determine the effect of steady-state digestion temperature on the operational stability and performance of the digestion process. Replicate reactors operated at 57.5 degrees C, the highest temperature studied, were prone to accumulation of volatile fatty acids (4052 and 3411 mg/L as acetate) and gaseous hydrogen. Reactors operated at or below 55 degrees C showed no such accumulation of intermediate metabolites. Overall methanogenesis was also greatly reduced at 57.5 degrees C (0.09 L CH4/g VS fed) versus optimal methane formation at 53 degrees C (0.40 L CH4/g VS fed). Microbial community assessment and free energy calculations suggest that the accumulation of fatty acids and hydrogen, and relatively poor methanogenic performance at 57.5 degrees C are likely due to temperature limitations of thermophilic aceticlastic methanogens.

Neurofibromin and its inactivation of Ras are prerequisites for osteoblast functioning.

Skeletal problems and osteoporosis occur in up to 50% affected neurofibromatosis type 1 (NF1) humans. Inactivation of neurofibromin results in deregulation of Ras signal transduction. Little is known of bone biology in humans with NF1. The goal of our work was to determine if loss-of-function of Nf1 gene was associated with altered bone homeostasis and Ras signal transduction. Because homozygous Nf1 mice are embryonically lethal, heterozygote Nf1 (Nf1+/-) male mice were used to investigate skeletal phenotypes and osteoprogenitor functions, using standard in vivo and in vitro assays. We found that bone mass and geometry of Nf1+/- mice did not differ from wild type controls, despite a trend to less bone formation. Nf1+/- committed osteoprogenitors from femur metaphysis exhibited premature apoptosis and higher proliferation. Ras signaling was activated in primary Nf1+/- bone marrow-inducible osteoprogenitors. Inducible osteoprogenitors exhibited lower induction of osteoblast differentiation, assessed as alkaline phosphatase positive CFU-f. A screen of osteoblast marker genes showed a selective increase in osteopontin (OPN) mRNA and protein expression in these cells. OPN protein was increased in Nf1+/- bone, especially in cortical bone matrix. Because bone cell abnormalities in Nf1 haploinsufficiency were detected in vitro, redundant pathways must compensate for the deregulation of Ras signaling in vivo to maintain normal bone mass and function in vivo. Our in vitro data revealed that neurofibromin and its control of Ras signaling are required for osteoprogenitor homeostasis.

Influence of smoking on the development of lung metastases from breast cancer.

BACKGROUND: This study examined the association between cigarette smoking status and the development of lung metastases in a group of 835 women diagnosed with primary malignant unilateral breast cancer. METHOD: Female patients with breast cancer diagnosed between 1982 and 1991 at Roswell Park Cancer Institute (RPCI) in Buffalo, New York, who provided information on their cigarette smoking history at the time of their diagnosis were included. The subsequent disease status of patients was monitored by the RPCI Tumor Registry. The Cox regression model was used to estimate the relationship between smoking status and the development of lung metastases, adjusting for the patient's age, stage of disease at diagnosis, and body weight. RESULTS: Of those patients who developed lung metastases, 8.7% were nonsmokers, 14.1% were former smokers, and 14.3% were current smokers. Tests showed that nonsmokers had significantly fewer lung metastases than either of the two smoking groups (P < 0.01). The estimated relative rates of lung metastases developing adjusting for age, stage, and body weight in women who smoked less than 10,000, between 10,001 and 20,000, and more than 20,000 packs over their lifetimes compared with nonsmokers were 1.06 (95% CI, 0.51-2.20), 3.10 (95% CI, 1.5-6.3), and 3.73 (95% CI, 1.6-8.9) respectively. The Cox regression model showed that every 1000 packs of cigarettes consumed over a lifetime increased a woman's risk of developing lung metastases by about 3% to 7% (P < 0.001). CONCLUSION: This study found a significant association between cigarette smoking history and risk of lung metastases developing in women diagnosed with primary invasive unilateral breast cancer. The risk of lung metastases developing increased as the number of cigarettes smoked in a lifetime increased.

The influence of surgical trauma on experimental metastasis.

Influence of surgical trauma on experimental metastasis in healing wounds is investigated using a transplantable murine mammary carcinoma cell line, TA3Ha. Intravenous injection of 10(5), 10(6), and 2 x 10(6) TA3Ha cells into syngeneic Strain A mice led to liver or kidney tumor development in none of the 96, ten, and ten mice tested, respectively. In contrast, injection of 10(5) cells into mice immediately after hepatic wedge resection performed using milliwatt carbon dioxide laser and electrocautery resulted in tumor formation at the site of trauma in 21/37 (57%) and 25/52 (48%) mice, (P less than 0.001) respectively. Similar results were obtained in mice subjected to partial nephrectomy using the laser (nine of 18) and electrocautery (eight of 13). These results clearly demonstrate that surgical trauma renders a nonprivileged organ susceptible to experimental metastasis formation, and that at least in this model both laser and electrocautery have similar effects. Tumor cell injection 1, 7, and 10 days posthepatic surgery resulted in 36%, 20%, and 0% tumor formation, respectively, indicating that the earlier events in wound healing support tumor implantation and/or growth better than those later on. Frequency of tumor formation at sites of trauma in the peritoneum induced by scalpel blade, laser, and electrocautery were 28%, 50% and 82%, respectively. Peritoneal tumors were seen in 33% of the nonsurgical mice. Skin incisions induced with the three above probes had little influence on experimental metastasis formation. Thus the influence of trauma on tumor formation is not uniform in every organ.

Milliwatt carbon dioxide laser and hepatic surgery in mice: surgical technique and pathology.

The milliwatt carbon dioxide laser was used to induce focal lesions and to perform wedge resections in the livers of 75 strain A mice. The procedures were feasible and well tolerated by the mice, with only one postoperative death in the wedge resection group in an early experiment. The hepatic lesions produced by the laser were characterized histologically by an inner area of vaporization, an intermediate area of coagulation necrosis, and an outer rim of cells with variable damage. The lesions healed by fibroblastic proliferation and scar formation with no hepatocytic contribution. The small vessel and bile ductule sealing effect of CO2 laser, together with the sound healing of laser-induced wounds, highlights the usefulness of this modality in liver surgery in general, and suggests its particular application in the treatment of liver trauma and a variety of hepatic focal lesions, neoplastic or otherwise.

Tn, a carcinoma-associated antigen, reacts with anti-Tn of normal human sera.

Tn antigen is the immediate precursor of the carcinoma (CA)-associated T antigen; both are masked in non-CA tissues. Tn antigen was detected by absorption of human anti-Tn antibody in 46 of 50 primary breast CAs and in all 6 metastases originating from Tn-positive primary CAs. Thirteen of 25 (52%) anaplastic CAs, but only 2 of 15 (13%) well differentiated CAs had more Tn than T; 1 anaplastic CA had neither antigen. Eighteen of 20 benign breast lesions had no Tn; the 2 positive lesions were premalignant. All 19 breast CAs, studied immunohistochemically, reacted strongly with human polyclonal anti-Tn; benign or normal glandular tissues had minimal or no reactivity. Among live cancer cell lines, the most malignant sublines had more Tn than T on their cell surfaces. Preliminary studies with rodent monoclonal anti-Tn and anti-T antibodies gave immunohistochemical reactivity patterns similar to those of the polyclonal antibodies, but the former were less sensitive in absorption tests. Tn is a CA marker that promises to be useful in tumor detection.

Patients' immune response to breast and lung carcinoma-associated Thomsen-Friedenreich (T) specificity.

We report here sensitive and specific measurement of immune responses of patients with certain kinds of carcinoma toward the physically and chemically well defined T antigen isolated from healthy human erythrocytes. Over 90% of adenocarcinoma tissues tested possess T-specific immunoreactive structures as determined with human antisera, in contrast to healthy tissues and benign lesions. Adenocarcinoma patients recognize the carcinoma-associated T antigen as foreign. Delayed-type skin hypersensitivity reaction to T antigen (DTHR-T) was positive in all 25 lung adenocarcinoma patients tested, in 88% of 101 patients with ductal, in 43% of 30 patients with lobular or tubular breast carcinoma and in 9/9 patients with adenocarcinoma of body cavities. Patients of all Stages reacted positively. All 7 patients with small cell lung carcinoma and 3/5 with malignant melanoma had a positive DTHR-T. None of 17 patients with malignant brain tumors, leukemia or Hodgkin's disease, sarcoma or thyroid carcinoma reacted. The DTHR-T was specific in that all 77 healthy persons and 48/49 with other diseases, including 23/24 with non-cancer lung disease were negative; one patient with organizing interstitial pneumonitis was positive. This points to a possible source of false positive reactions. 91% of 149 patients with histologically benign breast disease had a negative DTHR-T; the histology of some of the positive ones was reexamined, 2 proved to have carcinoma in situ.

The distribution of acid and alkaline ribonuclease activities in preneoplastic and neoplastic rat livers.

Ribonuclease (RNase) activities revealed by the substrate film method were compared with reactions for acid and alkaline RNase obtained by lead precipitation technique in serial sections of preneoplastic livers and hepatomas. The preneoplastic parenchymal tissue giving positive reactions with ribonucleic acid films showed both acid and alkaline RNase activities by lead precipitation technique, and the area of hyperplastic nodules nonreactive against substrate films were deficient in acid and alkaline RNase activities. Preneoplastic hyperbasophilic foci and hepatoma gave weak or negative reactions by either method, but necrotic areas and stromal tissue showed appreciable RNase activities. Thus a good correlation was observed in these tissues between the RNase activities revealed by the film method and those demonstrated by lead precipitation.