Evidence for a defective mitochondrial membrane in 1,2-dimethylhydrazine-induced colon adenocarcinoma in rat: enhanced lipid peroxidation potential in vitro.

Enhanced lipid peroxidation potential was measured in Holtzman rat colon tumors induced by chronic subcutaneous injection of 1,2-dimethyl-hydrazine as compared with normal colonic tissue. The peroxidation potentials were determined in the mitochondrial cellular components by measuring the ferrous-ascorbate induced formation of malondialdehyde. The tumor mitochondria were found to peroxidize at a rate 8-10-fold higher than the comparable normal tissue components. In addition, we found that the mitochondria from the cancer cells exhibited reduced NADH-cytochrome c reductase activity. These observations suggest an involvement of non-enzymatic free radical flux in DMH-induced carcinogenesis, which may be the result of structurally altered mitochondrial membranes.

Retinoblastoma Y79 cell line: a study of membrane structures.

The continuous retinoblastoma cell line Y79, grown in suspension culture, has been examined by transmission and scanning electron microscopy, including freeze-fracture replica preparations. Four classes of cells were distinguishable by their size and surface characteristics. The surface structures included blebs, filopodia, lamellipodia, microvilli, and microplicae. The possible origin of a most unusual type of cell, apparently forming natural clones, is discussed.

Types and sensitivity patterns of ocular pathogens.

The total number of specimens received for microbiologic examination and culture in a teaching hospital department of ophthalmology for the years 1974 and 1975 has been reviewed. The results have been analyzed, and information is presented on (a) the relative frequency of different types of bacteria, fungi, and viruses as causal agents of ocular inflammatory diseases and (b) the current pattern of antibiotic sensitivities.

Rheumatoid arthritis: review of searches for an infectious cause. Part I.

No distinctive pattern has yet emerged from the accumulated mass of results that would provide a generally acceptable hypothesis of the etiology of rheumatoid arthritis. A number of immunologic aberrations have been described, but there has been no identification of a key immunologic defect that might link together the various components of the immune response into an agreed pattern. The possibility of a persistent antigenic stimulus arising from an infection cannot be confirmed or refuted. If a virus is involved, it would seem more likely to be a "slow" virus rather than a commonly recognized form, but there is no strong candidate of this type in view. Despite the fact that mycoplasmas are undoubtedly arthritogenic in other species, their role as an etiologic agent in rheumatoid arthritis has not been proven. The idea that bacterial cell wall peptidoglycan may provide a persistent stimulus has much to offer, but it is not possible at this stage to accept peptidoglycan as a recognized etiologic factor. This suggestion will, however, indoubtedly stimulate much further investigation.

Cyclic nucleotide concentrations in 7.12-dimethylbenz[a]anthracene-induced pancreatic cancer in rats.

Pancreas cancer was induced in noninbred male Holtzman rats by the implantation of beeswax containing 7.12-dimethylbenz[a]anthracene (DMBA) into the "head" of the pancreas. The tumors that developed 4--6 months later were examined for their cyclic AMP and cyclic GMP levels. The lesions could be considered in one of two categories according to their cyclic nucleotide contents: lesions with significantly smaller amounts and those with greater amounts, compared with levels measured in the pancreas tissues of the control rats. The existence of two biochemically distinct groups may indicate different growth patterns of the DMBA-induced pancreatic neoplasia.

Helminthosporium corneal ulcers.

We studied four cases of Helminthosporium corneal ulcers from four different institutions. One case occurred in an immune-deficient infant, another in a patient three months after removal of a foreign body; the third case occurred in a patient with a corneal dystrophy who was wearing soft contact lenses and using topical corticosteroids; and the fourth occurred in a patient with a history of multiple foreign bodies. Antifungal sensitivities were performed in three cases and showed relatively good sensitivity to available antifungal medications; even though all four patients improved, there was poor correlation between in vitro sensitivities and clinical response.

A search for serum antibodies in Adie's syndrome.

Serum specimens from a large number of patients with Adie's syndrome were checked for virus antibody levels: Measles hemagglutination inhibition (HI), parainfluenza types I, II and III (HI), Epstein-Barr immunofluorescence, Mumps complement fixation (CF), Adenovirus (CF), Varicella-Zoster (CF), Herpes simplex (CF), Cytomegalovirus (CF), Mycoplasma hominis (CF), Toxoplasma gondii passive hemagglutination. These antibody levels were compared with specimens from a control group of similar age distribution and sex ratio. No statistically significant differences between the patients with Adie's syndrome and the control group could be demonstrated. This observation offers some indirect support to Harriman's idea that Adie's syndrome is not due to a viral ciliary ganglionitis but rather to an indolent neuronal degeneration in the ciliary and dorsal root ganglia.

Detection of HBsAg in coagulation Factor IX concentrates.

HBsAg was detected in two commercial clotting factor concentrates: Proplex (Hyland) and Konyne (Cutter). HBsAg was positive by RIA in samples of Proplex but not Konyne. Immune-electron microscopy, however, demonstrated clumped small spheres of HBsAg in both preparations, and lamellar-type strands were seen in several preparations.

Hepatitis-B: a review.

The recent literature on various aspects of hepatitis-B is reviewed with emphasis on the interrelationships of viral structure, antigenic components, and host immune response in acute, chronic, and asymptomatic carrier states of the infection. The mode of replication and mechanisms of transmission are discussed. Special attention is paid to potential non-parenteral routes of spread. The role of hepatitis-B in associated immune complex diseases and in hepatoma is outlined. A guide to the interpretation of serologic tests for hepatitis-B associated antigen and antibody patterns is presented in relation to the clinical stage and prognosis of the infection. Therapy, except in conceptual terms, is not covered but a summary of the current status of active and passive immunization is given. The unresolved question of the infectivity of carrier medical staff for their patient contacts, and the reverse, is discussed.

Quantitative assay of paravaccinia virus based on enumeration of inclusion-containing cells.

Bovine paravaccinia virus produces cytoplasmic inclusion bodies on infection of bovine embryonic kidney cells; these were easily recognized when stained with acridine orange or May-Grünwald-Giemsa stain. The inclusions could be shown to contain newly synthesized deoxyribonucleic acid by autoradiography. Counts of inclusion-containing cells decreased when virus suspensions were treated with immune serum before being used to inoculate cell cultures. At 24 hr after infection, the number of cells containing inclusions was directly proportional to the concentration of infectious virus inoculated. These observations provide the basis for a virus assay which is simpler, faster, and more sensitive than the plaque assay.