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Biomedical subjects

L Carter

Publications and source records attributed to L Carter.

At least 73 records · Page 4Linked to original sources
PubMed1987

Mammary stimulation and maternal aggression in rodents: thelectomy fails to reduce pre- or postpartum aggression in rats.

In mice, tactile stimulation of the nipples appears to be critical for the onset of postpartum maternal aggression. Surgical removal of the nipples (thelectomy) blocks aggression if performed prior to parturition. In rats, indirect evidence suggests a similar role for nipple stimulation in maternal aggression. Two experiments were undertaken to determine whether thelectomy prior to mating reduces pregnancy-induced and/or postpartum aggression in this species. In the first, thelectomized and sham-thelectomized females were subjected to home cage tests (pups, if any, present) with unfamiliar male intruders on Gestation Days 18 and 21 and Lactation Days 3 and 5. Additional groups of thelectomized females were tested one time only on either Lactation Day 5 or 12. Thelectomized and control females were equally aggressive; postpartum, nearly all females in both groups attacked. Experiment 2 used females that were hysterectomized-ovariectomized (HO) on Gestation Day 16. Such females are not aggressive prior to initiating maternal behavior, but become highly aggressive (over 80% attacking) after commencing maternal care. Females again were thelectomized or sham-thelectomized prior to mating. On Day 16 HO was performed, and 48 hr later continuous exposure to pups was begun. After the females had displayed maternal behavior for 1.5-2 days, intruder tests were conducted. All females attacked at least once, with no differences between treatment groups. Thus thelectomy does not reduce maternal aggression in the rat. This finding, however, does not preclude a role for tactile ventral stimulation in mediating maternal aggression.

Aggression↗
PubMed1987

The Family Rorschach with families of schizophrenics: replication and extension.

Using a modified version of procedures outlined by Shapiro and Wild (9), this study evaluates the use of a Family Rorschach technique as a means of distinguishing families of schizophrenic patients from those of psychiatrically hospitalized, nonschizophrenic individuals. The patients were diagnosed using Research Diagnostic Criteria, and families were matched for age, intelligence, and socioeconomic characteristics. Results showed that the families with schizophrenic offspring scored significantly lower (that is, they had more communication and attentional difficulties) than those with nonschizophrenic offspring; offspring gender and family constellation had little effect on scores. Subsequent analyses indicated that lower scores were not simply a reflection of the psychoticism of the patient. These findings suggest that families of schizophrenics have interpersonal communication difficulties that compromise their ability to maintain a shared focus of attention. The findings are consistent with the suggestion that deviant patterns of family communication in interaction with genetic vulnerability in an offspring may result in the development of a schizophrenic disorder.

Adult↗
PubMed1987

Antibody synthesis in the rat liver: an association between antibody-forming cells in the liver and biliary antibodies following intravenous injection of horse erythrocytes.

The transient appearance of IgM in the bile of rats injected intravenously with horse erythrocytes (HRBC) correlated with the occurrence of anti-HRBC IgM-secreting cells in the liver. Both responses were reduced in animals splenectomised at the time of immunisation. When rats were given 2 injections of HRBC spaced by 28 days, IgG, IgA and IgM antibody-forming cells (AFC) were detected in the liver along with IgM and non-IgM anti-HRBC antibody in bile. There was a 10-fold increase in the total numbers of mononuclear cells (MNC) retrievable from the liver at the height of the biliary antibody response, the majority of which were not AFC. These results suggest that antigen entering the spleen stimulates the release of a population of MNC which may localise in the liver and that a minor portion of these produces specific antibody which is secreted into bile.

Animals↗
PubMed1987

Antibody synthesis in the rat liver: a source of biliary IgM, IgA and IgG following injection of horse erythrocytes into the intestine or Peyer's patches.

Intestinal injection of HRBC into rats leads to: 1. an anti-HRBC response in serum and bile - HA activity in bile is associated with IgM, IgG and IgA. 2. an increase in total IgM in bile. 3. the presence of IgM, IgA and IgG AFC in liver. Equivalent AFC responses occur in livers of splenectomized rats. It is concluded that the results are consistent with the proposal that the liver is a site for localization of antibody-secreting cells which enter the blood and that these cells are a source of biliary antibody.

Animals↗
PubMed1986

Mitochondrial acetoacetyl-CoA thiolase deficiency.

A patient with severe progressive neuropathy and growth retardation who showed a persistent ketosis despite normal blood glucose levels is described. A liver biopsy was analyzed for 3-oxoacyl-CoA thiolase activity. One of the mitochondrial 3-oxoacyl-CoA thiolases which in normal control liver could be activated by K+ was virtually absent in the patient's liver. An intensive search for 3-methylhydroxybutyric acid and 3-methylacetoacetic acid by gas chromatography/mass spectroscopy in the patient's urine failed to show the presence of these acids, demonstrating that the 3-methylacetoacetyl-CoA thiolase is functioning in this patient. It is therefore concluded that the persistent ketosis is due to a deficiency of the mitochondrial acetoacetyl-CoA specific thiolase.

Acetyl-CoA C-Acyltransferase↗
PubMed1984

Studies on the origins of biliary immunoglobulins in rats.

This study was designed to investigate the origins of biliary immunoglobulins in rats. Natural antibodies to species of Lactobacillus and Staphylococcus were detected in blood, bile, and lymph, with predominant activity being associated with immunoglobulin A in lymph and bile and with immunoglobulins M and G in blood. Six hours after thoracic duct cannulation, serum immunoglobulins G, M, and A had fallen to 60%, 65%, and 40%, respectively, of the preoperative levels, whereas the level of total and specific immunoglobulin A in bile was reduced to 25% with no significant decline of immunoglobulin G. Thoracic duct occlusion caused a similar selective reduction in biliary immunoglobulin A. It is calculated that 50% of thoracic duct lymph immunoglobulin A entering the blood is secreted in bile. Synthesis of immunoglobulins M, G, and A in the liver was established by the detection of antibody-secreting cells. It is proposed that the major part of biliary immunoglobulin A is derived from intestinal lymphoid tissues and that a portion of the remainder, as well as part of biliary immunoglobulins M and G, results from local synthesis.

Animals↗
PubMed1983

Effect of storage on insulin receptor binding in human erythrocytes.

The authors established the specificity, reliability, and precision of human erythrocyte insulin radioreceptor assay. On the basis of insulin binding, cell viability, and degree of hemolysis, heparin sodium was found to be a more suitable anticoagulant than sodium fluoride, ethylenediaminetetraacetic acid, sodium oxalate, or sodium citrate. In two sets of experiments carried out at 4°C and 23°C, human erythrocytes were stored as whole blood or isolated erythrocytes suspended in Tris-{4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid} buffer. The effect of storage under these conditions was evaluated by erythrocytespecific insulin binding. Human erythrocytes can be stored for 72 hours at 4°C without any change in insulin binding, insulin receptor sites per cell, or average affinity constant at the empty sites. Isolated erythrocytes can also be stored in plasma for 72 hours or in buffer G for 24 hours at 4°C without any change in insulin binding. It is not advisable to store human erythrocytes in plasma or as whole blood for more than 24 hours at 23°. These findings are useful in preserving insulin receptor activity when storage of erythrocytes is unavoidable.

Anticoagulants↗
PubMed1982

Biochemical and morphological effects of 20,25-diazacholesterol on cultured muscle cells.

Effects of 20,25-diazacholesterol (DAC), a myotonia-inducing drug, were evaluated on certain biochemical and morphological properties of embryonic rat muscle cells grown in tissue culture. During DAC treatment, muscle fibers exhibited spontaneous contractions that changed from coarse twitches to finer fibrillation movements, The ultrastructural alterations produced by DAC were smeared Z-lines, disorganized myofibrils, occasional honeycomb appearance of membranes and large vacuoles connected to zipper-like structures. Biochemically, a microsomal fraction prepared from DAC-treated cells (compared to that of normal cells) showed a 30-45 per cent decrease in the isoproterenol-enhanced and the NaF-enhanced adenylate cyclase activity. however, the beta-adrenergic receptors, through which isoproterenol activates the enzyme, showed no change in density or affinity as judged by the binding of [125I]iodohydroxybenzylpindolol. That indicated that DAC treatment caused an uncoupling of beta-receptor-adenylate cyclase interaction. Guanylate cyclase and cyclic GMP-phosphodiesterase were both markedly increased in DAC-treated cells, indicating a greater turnover of cyclic GMP. Binding of [3H]concanavalin A to DAC-treated muscle membranes was decreased 20-40 per cent. The data indicate that DAC exert a direct influence on muscle fibers, affecting their functional, biochemical and morphological properties.

Animals↗
PubMed1982

Schizophrenic children's utilization of images and words in performance of cognitive tasks.

Hospitalized schizophrenic (N = 15) and nonschizophrenic (N = 18) youngsters were compared on measures of verbal and imagery development as well as on four paired-associate learning tasks involving combinations of word and picture stimuli pairs. The results showed the schizophrenic group to be similar to the controls on verbal and full-scale intelligence measures but significantly inferior on performance measures. The schizophrenic group also showed a general disadvantage in paired-associate learning, with a trend toward specific differential difficulty with words as stimulus items. Results suggest the presence of nondominant hemisphere deficit in the target group and also provide weak support for theories of dominant hemisphere dysfunction in schizophrenia.

Association Learning↗
PubMed1981

Aflatoxin M1 in manufactured dairy products produced in the United States in 1979.

In a 1979 survey of manufactured dairy products (992 samples of nonfat dry milk, vanilla ice cream, yogurt, Cheddar cheese, and cottage cheese) for aflatoxin M1 contamination, one sample, a cottage cheese, had detectable aflatoxin equivalent to .08 ng/ml in the milk from which the product was made. Samples were taken by Food and Drug District inspectors from randomly selected establishments at three times throughout the year. The distribution of sample quotas to each District was weighted to double the representation of establishments in the southern tier of states. The conclusion from this survey is that in a "normal" year aflatoxin M1 should not be in a manufactured dairy product in the United States at a level in excess of that from milk with .1 ng aflatoxin M1/ml.

Aflatoxin M1↗
PubMed1980

A simplified intrapartum numerical scoring system. The prediction of high risk in labor.

An analysis of 1,994 consecutive parturient women showed that 472 (23%) could be assigned to a high-risk category on the basis of an intrapartum score of greater than or equal to 3. Perinatal mortality, neonatal morbidity, and the rate for operative intervention were all significantly greater for the high-risk group (p < 0.0001). Of the total population, 11% were designated to be at high risk by combining intrapartum and antepartum scores, and 71% of this group had an abnormal intrapartum outcome (p < 0.0001). For this study, 63% of the patients with an abnormal outcome for labor were admitted to the labor floor for 6 hours or longer, and this is an indirect measurement of the potential that exists for optional management. The limitations of intrapartum scoring systems are discussed, particularly with respect to their design, the prediction of preventable deaths, and the category of hospital for which they might prove most useful.

Female↗
PubMed1979

Erythrocytes: a new cell type for the evaluation of insulin receptor defects in diabetic humans.

Human erythrocytes have specific insulin receptors. When studied in an insulin radioreceptor assay, erythrocytes from adult-onset, nonobese diabetic subjects bound at least 42 percent less insulin than the normal subjects at insulin concentrations from 0.1 to 100 nanograms per milliliter. The diabetic subjects had 190 insulin receptor sites per cell as compared with the 380 insulin receptor sites per cell for the normal subjects. The deficit of insulin binding in the diabetic subject was thus associated with a fewer number of insulin binding sites per cell with little or no change in affinity. The erythrocyte is a readily available cell for the evaluation of cellular insulin receptor activity.

Adult↗