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Biomedical subjects

N Adams

Publications and source records attributed to N Adams.

At least 55 records · Page 3Linked to original sources
PubMed1991

The effect of a high salt diet and gender on blood pressure, urinary protein excretion and renal pathology in SHR rats.

A high salt diet produced increases in SBP, urinary protein excretion (UPE) and renal vascular lesions (RVL) across groups of male and female SHR rats which were allowed to develop moderate or excessive increases in SBP. A highly significant linear relationship between SBP and log-transformed UPE was found when the data from all groups were analyzed together. Males developed high blood-pressure more rapidly, and exhibited more severe RVL and greater UPE than females. Two results prevent the conclusion that the elevated UPE was simply due to the adverse effects of high BP on the kidney. First, the relationship between SBP and UPE across groups could not be demonstrated when regression analyses were performed within individual dietary sub-groups. Secondly, gender differences in UPE were highly significant by analysis of covariance adjusting for individual differences in SBP. The increases in SBP and UPE may be independent consequences of ingestion of a high salt diet.

Animals↗
PubMed1991

Dietary salt and accelerated hypertension: lack of sub-line differentiation in spontaneously hypertensive rat stocks from the United States.

We compared the ability of a high-NaCl diet to produce blood pressure elevation in spontaneously hypertensive rats (SHR) from the major North American commercial suppliers (Harlan, Taconic Farms, Charles River) and SHR and stroke-prone SHR (SHRSP) from the National Institutes of Health (NIH). Animals were raised on a low-NaCl diet containing 0.30% NaCl and placed on an 8.0% NaCl diet at 37 days of age. In males, the high-NaCl diet produced large increments in blood pressure within 2-4 weeks, which were similar in magnitude for all SHR derivations. In females, increments in blood pressure occurred more slowly than in males but, in most SHR derivations, the absolute blood pressure level eventually reached was similar to that seen in males. The present findings provide no evidence of sub-line differentiation among SHR stocks from the United States regarding the blood pressure-augmenting effects of increased levels of NaCl and are consistent with the results of DNA fingerprinting studies, which have not found any genetic variation between SHR from different colonies. We speculate that the pervasive gender differences in the blood pressure response to the high-NaCl diet in SHR may reflect gender differences in food intake, and hence the dose of NaCl received, rather than intrinsic differences between males and females. On the other hand, the lack of significant gender differences in blood pressure response to the high-NaCl diet in SHRSP may reflect the genetic differences which are known to exist between this strain and the main SHR stemline.

Animals↗
PubMed1991

Efficacy evaluation of physostigmine and anticholinergic adjuncts as a pretreatment for nerve agent intoxication.

Pretreatment of nonhuman primates with physostigmine (Phy) and scopolamine or physostigmine and trihexyphenidyl 25 min before exposure to 2 LD50 soman im resulted in complete survival without convulsions or loss of consciousness. When identically pretreated animals were challenged with 5 LD50s of soman followed by atropine and 2-PAM therapy 1 min later, all animals experienced a loss of consciousness for approximately 10 min followed by functional recovery within an additional 20 min. These findings indicated that a pretreatment regimen composed of Phy and cholinolytic is capable of protecting primates from an absolute lethal dose of soman with rapid recovery from incapacitation.

Animals↗
PubMed1990

Synthesis and antitumor activity of novel 4-demethoxyanthracyclines.

A versatile and efficient synthetic route to 4-demethoxyanthracyclinones has been utilized in the preparation of a number of aglycons having 9-alkyl, 9-(hydroxylalkyl), or 9-carbamoyl substituents. Silver trifluoromethanesulfonate catalyzed coupling of these aglycons with various daunosamine derivatives has yielded a series of novel anthracyclines which have been evaluated as antitumor agents. 9-Alkylanthracyclines 22, 23, 33, and 34 have higher efficacy vs L-1210 leukemia than the parent 4-demethoxydaunorubicin (21), or the natural anthracyclines daunorubicin (1) and doxorubicin (2). 9-(Hydroxyalkyl) derivatives have in most cases high efficacy but are slightly less potent than 21. 9-Methyl analogue 22 has higher efficacy vs P388 leukemia than other anthracyclines tested, while 9-(hydroxymethyl) derivative 37 retains similar efficacy to anthracyclines 1, 2, and 21 but is considerably more potent. The N-substituted 9-carbamoylanthracyclines are devoid of antitumor activity.

Animals↗
PubMed1990

Synthesis and antitumor activity of 9-[(carbamoyloxy)alkyl]anthracyclines: a novel class of anthracycline derivatives.

A number of 4-demethoxyanthracyclines having hydroxylalkyl functions at the 9-position have previously been synthesized and shown to have potent antitumor activity. A series of carbamate derivatives of these (hydroxyalkyl)anthracyclines have now been prepared, many of which possess considerably greater efficacy in an L-1210 leukemia test system than do the parent alcohols or the known anthracyclines daunorubicin (1), doxorubicin (2), and 4-demethoxydaunorubicin (3). Phenylcarbamate 8a was more active than methyl analogue 8b, while the 4'-deoxy and 4'-epi phenylcarbamates 17 and 18 showed particularly high efficacy at optimal dose levels similar to that of doxorubicin. Secondary carbamates were more potent, with the 13R isomer 23 having significantly higher efficacy than 13S analogue 24.

Animals↗
PubMed1990

Modification of stroke susceptibility by genotype-dependent maternal influences.

The influence of the prenatal and postnatal maternal environment on stroke susceptibility was evaluated by reciprocally crossing the spontaneously hypertensive (SHR) and the Dahl salt-sensitive (SS/Jr) inbred rat strains to produce reciprocal F1 hybrids that were nurtured, respectively, during prenatal and postnatal life by SHR or SS/Jr mothers. Following placement on a high-salt diet containing 8% NaCl at 35 days of age, F1 rats reared by SHR mothers had shorter survival times and were more likely to die with cerebral hemorrhage than F1s reared by SS/Jrs. Across reciprocal F1 female groups, enhanced susceptibility to stroke was associated with greater elevations of systolic blood pressure, but this association was not seen across reciprocal F1 male groups. There was also an association between blood pressure and stroke within each F1/gender subgroup: Rats eventually suffering strokes developed higher blood pressure after placement on the high-salt diet than rats that did not suffer stroke. Lower day 35 body weights (before exposure to the high-salt diet) were associated with greater likelihood of stroke both across the reciprocal F1 groups, and within three of the four F1/gender subgroups. The differences in stroke susceptibility between the reciprocal F1 groupings may be due to systematic differences in the prenatal and/or postnatal environments of SHR and SS/Jr mothers and may be mediated by variations in the nutritive capacity of the two inbred mothers.

Animals↗
PubMed1988

Familial 'sleep apnea plus' syndrome: report of a family.

We describe a familial disorder consisting of sleep apnea, anosmia, colorblindness, partial complex seizures, and cognitive dysfunction. The phenotypic expression of the syndrome suggests an autosomal dominant inheritance with incomplete penetrance.

Adult↗
PubMed1987

Contrasting effects of social stress and foot-shock on acute cardiovascular response in salt-sensitive rats.

Repeated defeat by an aggressive resident attacker rat produces a large decrement in systolic blood pressure (SBP) in male S/JR rats. The present experiments compared the cardiovascular (CV) response of male S/JR rats exposed either to repeated defeat, or to a common laboratory stressor, electric foot-shock. Using the tail-cuff method of determining SBP, the results of Experiment 1 replicated the previous finding that on the second and subsequent exposures, repeated defeat is followed by an acute decrement in SBP (30-40 mm Hg in magnitude). In contrast, repeated exposures to foot-shock were followed by acute increases in SBP (20-40 mm Hg) and in heart rate (HR). In Experiment 2, mean arterial blood pressure (MAP) and HR were measured directly from chronically cannulated male S/JR rats after defeat or exposure to foot-shock: again, defeated males exhibited an acute decrease in MAP, whereas the MAP of rats exposed to foot-shock tended to increase. In Experiment 3 we varied the parameters of shock intensity and the social context of shock exposure. Male S/JR rats exposed to more intense foot-shock than in the previous experiments or to foot-shock while paired with one of the resident attacker rats all exhibited acute increases in SBP. The results of these experiments indicate that CV response to defeat may be qualitatively different from CV response to foot-shock.

Aggression↗
PubMed1986

Effects of social defeat on acute cardiovascular response in salt-sensitive and salt-resistant rats.

We studied the effects of social stress (SS) and a high salt diet on systolic blood pressure (SBP) and heart rate (HR): S/JR male rats (which exhibit marked elevations in SBP when placed on a high sodium diet) and R/JR male rats (which are resistant to the BP-elevating effects of a high sodium diet) were maintained on a low sodium diet (0.3% NaCl) or placed on a high sodium diet (8% NaCl). Within each dietary condition independent groups were either exposed to SS, by placement in the cage of a trained fighter male (Long-Evans breed) for 25 min, or exposed to no stress. The dietary regimen was imposed for 10 days with stress exposures on Days 1, 2, 3, 5, 7, and 9, with SBP and HR measured indirectly by tail plethysmography 3 min following exposure to SS. SS produced an acute decrease in SBP (20-30 mm Hg) in S/JR rats on the second and subsequent exposures, but did not affect HR. SS did not affect SBP of R/JR rats, but did produce a significant elevation of HR. Maintenance on the high sodium diet increased SBP in S/JR, but not R/JR, rats when it was measured on the eighth (no stress) day, but SS obscured the effects of diet on SBP on days when rats were stressed. Following exposure to attacks, defeated SS rats displayed an upright submissive posture relatively late during the first stress exposure when no change in SBP was observed after SS in S/JRs, but displayed the submissive posture immediately and with long duration on the second and subsequent exposures when a marked decrement in SBP was seen.

Aggression↗
PubMed1985

The effects of pesticides on algae.

This paper reviews the effect on algae of organochlorine, carbamate, organophosphorus and other groups of pesticides, but excluding herbicides and general metabolic inhibitors. Existing data are often fragmentary and contradictory. Possible reasons for contradictory data are explored and discussed and the value of existing standard algal toxicity tests for environmental impact assessment is seriously questioned.

Carbamates↗
PubMed1984

Rapid determination of salicylate in serum on a centrifugal analyzer.

A bichromatic method is described for the determination of salicylate using a micro centrifugal analyzer. Salicylate was quantitated based on its reaction with ferric ion to produce a violet-colored complex. The method provides sample blanking and allows for rapid determination of salicylate levels in serum.

Bilirubin↗
PubMed1983

Effects of Met-enkephalin and naloxone on gastric emptying and secretion in rhesus monkeys.

Recent studies have demonstrated the presence of enkephalins in gastric neurons and endocrine cells; however, their role in the regulation of gastric function is unknown. The effect of Met-enkephalin (MET), the stable analogue of Met-enkephalin [D-Ala2]Met-enkephalinamide (DMET), and the opiate receptor antagonist naloxone were studied in five chair-adapted rhesus monkeys. A dye-dilution technique was used to determine simultaneously fractional emptying rate, hydrogen, sodium, potassium, and chloride ion output, and fluid output. Both MET and DMET significantly inhibited fractional emptying rate and H+ secretion following an 80-ml water meal. Only MET, however, significantly altered fluid and sodium ion output. Naloxone had no effect on gastric function following the water meal.

Animals↗
PubMed1983

The inter-domain among personality and cognition variables in people who commit murder.

The inter-domain among personality (MMPI) and cognition (intelligence) variables in a sample of 137 males charged with first degree or capital murder was examined through canonical analysis. Race was included as a control variable. Two significant canonical correlations were found which contribute to an understanding of the relationship between personality and cognition in violent people. These variates were identified as Problem-solving Focus and Introspective Self-focus. Results also suggest that these inter-domain variates explain the relationship between personality and cognition variables to a greater degree for black murderers than for white murderers.

Adult↗
PubMed1983

Genetic influences on digging behaviors in mice (Mus musculus) in laboratory and seminatural settings.

Digging behaviors of several inbred strains of laboratory mice and some of their crosses were examined in three contexts. In laboratory burrow boxes, C57BL/6Abg mice constructed more sophisticated burrow systems than did BALB/cAbg mice. Their F1 hybrids built burrow systems more complex than either parental strain. The same pattern of genetic influence was observed in an outdoor pen. In an escape task that required digging, BALB/c mice escaped more quickly than did C57BL/6 mice; their F1 hybrids showed dominance toward the BALB/c phenotype. These results indicate that behavioral polymorphisms in digging behavior, which may relate to habitat selection, have a genetic basis. The dominance and overdominance toward the better digging parental strain in each type of task suggest the possible evolutionary importance of these digging behaviors.

Animals↗
PubMed1982

The relationship between two Wiggins Content Scales and length of hospitalization.

Investigated the relationship between the Depression and Psychoticism Wiggins content scales of the MMPI and length of hospitalization on a psychiatric unit. Ss were 45 (23 males, 22 females) inpatients who were referred for psychological evaluation. The best single predictor of length of hospitalization was the Depression scale (p less than .001). The Psychoticism scale did not predict length of stay when used independently or in conjunction with the Depression scale. The content of an individual's self-description appears to be useful clinical information; future research was recommended.

Adjustment Disorders↗