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Biomedical subjects

M A Lane

Publications and source records attributed to M A Lane.

At least 19 recordsLinked to original sources
PubMed1992

Dietary restriction in nonhuman primates: progress report on the NIA study.

Rhesus and squirrel monkeys have been fed a semisynthetic diet at approximately ad libitum or 30% reduced levels for 3.5 (rhesus group 2) to 4.5 (rhesus group 1 and squirrel) years. Animals have maintained excellent health status as determined by physical examinations, hematology, and blood chemistry. While relative rates of body weight gain in restricted group 1 rhesus and squirrel monkeys have been markedly reduced, DR effects on crown-rump length (body height) have been variable. In addition, numerous physiological and biochemical parameters have been measured, and several exhibit significant cross-sectional age effects. Interestingly, several of these also exhibit possible species and genotype (group 1 and 2 rhesus) differences. A number of physiological parameters are emerging that might be altered by DR; however, further explanation of these effects awaits more extensive and detailed analyses.

Aging↗
PubMed1992

Loss of the 17p chromosomal region in a metastatic carcinoma of the prostate.

Genetic alterations of multiple loci that serve as markers for the induction and progression of disease have been identified in several adenocarcinomas, but not in adenocarcinoma of the prostate. To determine if similar genetic alterations occur in prostate carcinoma and could serve as markers for the extent of clinical disease, we have examined 23 predominantly moderately-differentiated, localized prostate carcinomas and one prostatic dysplasia for changes in the structure and copy number of ten selected genes. These genes include 1) those important to androgen metabolism in the prostate, the androgen receptor and steroid 5 alpha reductase genes; 2) those that map to the 10q (PLAU) and 7q (MET) chromosomal regions found deleted in some prostate carcinomas, and 3) proto-oncogenes (ERBB2, INT2, and MYC) and tumor suppressor gene loci (RB1, TP53 and D17S5) found altered in adenocarcinomas of the breast, colon and lung. Gene alterations were detected in one specimen, a lymph node metastasis from a poorly differentiated tumor. This specimen exhibited loss of heterozygosity for two loci putatively active in tumor suppression, TP53 and D17S5, on the short arm of chromosome 17. This study indicates that gross genetic alterations were not evident and could not be used as markers of tumor development in well- or moderately-differentiated, localized lesions, but that loss of the 17p region may be a useful marker for advanced carcinomas in the prostate.

Adenocarcinoma↗
PubMed1992

In situ dephosphorylation of p53 protein by calf intestinal alkaline phosphatase treatment.

The monoclonal antibody (mAb) 1801 has been reported to identify an N-terminal determinant within the tumor-suppressor protein p53 located between amino acids 32 and 79. This region contains two potential sites for serine phosphorylation at amino acids 33 and 46. Using a novel technique which dephosphorylates proteins in situ in fixed permeabilized cells, we have unmasked determinants in p53 recognized by mAb 1801, allowing additional sites of p53 protein to be detected in immunohistochemically reacted cells. This result indicates that phosphorylation at one or both sites within the determinant recognized by mAb 1801 previously blocked antibody-ligand interaction. It further suggests that in situ dephosphorylation may be of more general use in identifying antibodies which can only bind to epitopes in a particular phosphorylation state.

Alkaline Phosphatase↗
PubMed1991

Identification and initial characterization of glucose-repressible promoters of Streptococcus mutans.

Three catabolite-repressible promoters from Streptococcus mutans have been isolated. These promoters were identified by utilizing the vector pRQ200 which contains a promoterless amylase-encoding gene, a Gram- origin of replication, and an erythromycin-resistance determinant. A library of S. mutans DNA was constructed in pRQ200, amplified in Escherichia coli and integrated by Campbell-type insertion into the S. mutans chromosome following transformation. Colonies exhibiting amylase production on media lacking an extraneous carbohydrate source were screened for diminished amylase production on media containing glucose. The effect of glucose on these promoters has been characterized using a quantitative spectrophotometric assay of amylase activity.

Amylases↗
PubMed1979

Cellular immunity in aging.

Our study of the aging process in human beings and in mice is complicated by our need to know whether we are observing diseases of aging or natural nondisease state processes. Results from studies on inbred strains of mice and retrospective studies on HLA types in aging human populations suggest that genetic effects play a significant role in predetermining the life span of an individual. It is clear that in such mouse strains genetic defects that affect cell regulatory mechanisms result in the production of autoimmune reactivity, tumor development, and a shortened life span. In human beings, although results are less clear-cut, strong associations exist between some disease states and the HLA type. Also, the disappearance of HLA-B8 from older women suggests that this HLA type does not confer longevity. Cellular immune reactivity declines with age in all populations studied to date, and cell cooperative or regulatory mechanisms function less well. We need to characterize the specific nature of the cells directly responsible for these alterations and to attempt to correct deficiencies by dietary manipulation or transfer techniques.

Aging↗
PubMed1978

Modulation of mouse mammary tumor virus production in the MJY-alpha cell line.

Implantation of the mouse mammary tumor virus (MMTV)-producing mammary tumor cell line MJY-alpha into isogeneic mice elicited both humoral and T-cell responses against MMTV virion antigens. The carcinosarcomas which developed from the implanted cells showed a significant decrease in MMTV synthesis, compared with cells remaining in culture, which was detectable as early as 7 days after implantation and for five transplant generations. Electron microscopic examination of thin sections of the tumors revealed that intracytoplasmic A particles, budding particles, and cell-free MMTV B particles were all affected. However, immunofluorescence assays of tumor sections demonstrated the presence of MMTV viral antigens in the cells. Cell cultures initiated from first-, third-, and fourth-generation tumors were morphologically identical to the original in vitro cell line, although virus production was barely detectable. Analysis of the cultures by electron microscopy revealed a significant increase in MMTV virions after in vitro passage 3. Polypeptide profiles obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of virions purified from these cultures were identical to MMTV. Immunodiffusion demonstrated the cross-reactivity between these virions and MMTV particles obtained from mouse milk. In vitro treatment of MJY-alpha cell cultures with rabbit anti-MMTV antiserum resulted in a reduction of extracellular MMTV virions, as well as alterations in their sodium dodecyl sulfate-polyacrylamide gel electrophoretic polypeptide patterns.

Animals↗
PubMed1978

Muscarinic cholinergic activation of mouse spleen cells cytotoxic to tumor cells in vitro.

Carbamylcholine, acting via a pharmacologically specific receptor, had the ability to activate effector populations of spleen cells from female BALB/cfC3H and BALB/c mice; those cell populations were then significantly reactive in vitro against syngeneic tumor target cells but were only minimally reactive to normal syngeneic target tissues. The induced reactivity was inhibited by the muscarinic cholinergic antagonists atropine, scopolamine, and isopropamide, but not by the nicotinic antagonist d-tubocurare, and it appeared to involve both T-cell and non-T-cell effectors.

Animals↗
PubMed1977

Effect of immune manipulation on natural immune responses to murine mammary tumor antigens.

The virus-host relationship in BALB/cfC3H virgin female mice neonatally infected with an oncogenic virus (mammary tumor virus) (MuMTV) was significantly altered by a brief immunosuppressive treatment during young adult life. Natural immune responses were augmented and changed. The ability of lymphoid cells to attack target cells expressing MuMTV-associated antigens was significantly increased, and a new component, a non-T-cell reactivity, was added to the T-cell reactivity found in normal females. Serum blocking factors were both quantitatively and qualitatively altered.

Animals↗
PubMed1976

Innervation of heart cells in culture by an endogenous source of cholinergic neurons.

Hearts of embryonic mice 9 days in utero were found to have an endogenous source of cholinergic neurons which can survive in dispersed cell cultures. These neurons are electrically excitable, have ultrastructural characteristics of cholinergic embryonic neurons, and functionally innervate heart cells in culture. The nature of the innervation described is muscarinic cholinergic.

Animals↗
PubMed1976

Antibody in the sera of tumor-bearing mice that mediates spleen cell cytotoxicity toward the autologous tumor.

Pretreatment of MTV-induced BALB/cfC3H mammary tumor cells with autologous serum results in increased spleen cell cytotoxic activity and the recruitment of previously inactive spleen cells to cytotoxic activity against the target cells. These recruiting antibodies are tumor-specific for individual tumors; pretreatment with such serum of target cells of an MTV-induced mammary tumor obtained from a different BALB/cfC3H female results in blocking of spleen cell activity. The autologous recruiting factors are active at dilutions of 1000 or more of whole serum are found in the 19S fraction after gel filtration.

Animals↗
PubMed1976

Complexity of factors in sera of different mice that affect MTV-induced mammary tumor cells.

Specific spleen cell activity in microcytotoxicity assay can be altered by pretreatment of target mammary tumor virus (MTV)-induced mammary tumor cells with serum. Serum from both BALB/cfC3H females neonatally infected with MTV and BALB/c females horizontally exposed to MTV antigens will block specific spleen cell activity against isologous mammary tumor cells. On fractionation of sera, blocking factors are localized in the 7s fraction. The 19s fraction contains recruiting factors that are not detectable in the unfractionated serum; these factors are active against isologous tumors and are thus distinct from the tumor-specific recruiting factors previously described in the sera of tumor-bearing females, which are active only against the autologous tumor. Antibodies mediating complement-dependent cell lysis are also detectable after serum fractionation.

Animals↗
PubMed1976

Stimulation of immune mechanisms against mammary tumors by incomplete T cell depletion.

When BALB/cfC3H females are subjected to continous suction thymectomy, a procedure that results in retention of thymic remnants, the latent period before tumor development is significantly prolonged. However, when BALB/cfC3H females are thymectomized by control suction, a procedure which removes thymic lobes completely, there is no effect on mammary tumorigenesis. Our results show that incomplete T cell depletion causes premature onset of non-T cell cytotoxicity, an augmentation of T cell cytotoxicity, and an alteration in a serum-blocking activity to mammary tumor target cells as tested in microcytotoxicity assay. On the other hand, complete neonatal thymectomy effectively and completely abrogates immune response to mammary tumor target cells. The inability of completely thymectomized mice to generate an immune response to MTV suggests (but does not prove) that MTV-induced mammary tumor target cell surface antigens are thymus-dependent.

Aging↗
PubMed1975

In vitro detection of immune responses to MTV-induced mammary tumors: qualitative differences in response detected by time studies.

Both BALB/cfC3H females neonatally infected with mammary tumor virus (MTV) and MTV-free BALB/c females possess spleen cells capable of significant activity against target-MTV-induced mammary tumor cells in in vitro microcytotoxicity tests. The responses of the BALB/cfC3H and BALB/c females are different, however, on the basis of time studies. Further, the reactivity characteristic of virgin BALB/cfC3H females is increased in parous females, and part of this reactivity is subsequently lost in multiparous females bearing large tumors. BALB/cfC3H females possess reactive spleen cells as early as 3 weeks of age, indicating that response to MTV antigens develops soon after birth in these neonatally infected mice.

Age Factors↗
PubMed1975

Non-T cell killing of mammary tumor cells by spleen cells: secretion of antibody and recruitment of cells.

Both T cell-mediated killing and non-T cell-mediated killing of target MTV-induced mammary tumor cells can be detected in microcytotoxicity assay tests of spleen cells from mice immunologically responsive to either the histocompatibility antigens or the virus-associated antigens of the target cells. The non-T cell-mediated cytotoxicity is antibody-dependent; otherwise inactive cells (null cells) can be recruited to activity by target cell-specific factors obtained from the supernatant of short-term cultures of sensitized B cells or provided by the introduction of a small number of sensitized B cells to the wells of the assay plate.

Animals↗