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Biomedical subjects

N Campbell

Publications and source records attributed to N Campbell.

At least 73 records · Page 4Linked to original sources
PubMed1990

Comparative behavioral, neurochemical and pharmacological activities of dihydropyridine calcium channel activating drugs.

The behavioral (deficits in motor function in mice), neurochemical (affinity for mouse brain membrane dihydropyridine receptors, effects on neurotransmitter/metabolite levels in mice) and pharmacologic (effect on the contractile activity of guinea pig ileal longitudinal smooth muscle) properties of the calcium channel activators (+/-)-BAY K 8644, (+/-)-202-791 (and their corresponding channel activating and antagonist enantiomers) and CGP-28392 were investigated and compared. The calcium channel activating enantiomers (-)-S-BAY K 8644, (+)-S-202-791 and (+/-)-BAY K 8644, (+/-)-202-791 and CGP-28392 produced a dose-dependent impairment of rotarod ability and decreases in motor activity in mice with the following order of potency: (-)-S-BAY K 8644 greater than (+/-)-BAY K 8644 much greater than (+)-S-202-791 greater than (+/-)-202-791 = CGP-28392. The calcium channel antagonists (+)-R-BAY K 8644 and (-)-R-202-791 were behaviorally inactive but blocked the behavioral effects of (-)-S-BAY K 8644. The binding of dihydropyridine calcium channel activator and antagonist enantiomers to mouse brain membranes was described by both one and two site models. (-)-S-BAY K 8644, (+/-)-BAY K 8644, (+)-S-202-791 and CGP-28392 produced contractions in partially depolarized (15 mM K+) strips of guinea pig ileal longitudinal smooth muscle which differed in the degree of maximum contraction obtained. (+)-R-BAY K 8644 and (-)-R-202-791 inhibited potassium-induced contractions (80 mM K+) in guinea pig ileal longitudinal smooth muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1989

Anniversary reactions and due date responses following abortion.

Of 83 women who responded to surveys exploring postabortion coping, 30 women reported anniversary reactions associated with the abortion or due date. Women in the anniversary reaction group more often reported ambivalence about the decision to abort (p less than 0.007). This group also acknowledged fewer suicidal thoughts and attempts, but expressed more concern about verbally abusing their children (p less than 0.04). Strong trends toward dependency and somatoform disorders were present among anniversary group members (p less than 0.06). The authors recommend that physicians be alert to the possibility of hidden anniversary reactions of both physical and emotional nature during patient evaluation.

Abortion, Induced↗
PubMed1988

Alteration of methyldopa absorption, metabolism, and blood pressure control caused by ferrous sulfate and ferrous gluconate.

This study examined the effect of two widely used iron treatments on methyldopa absorption, metabolism, and blood pressure control. A 500 mg tablet of methyldopa (2.37 mmol) was taken with and without ferrous sulfate (325 mg) by 12 normal subjects in a randomized crossover trial. When ferrous sulfate was taken with methyldopa there was a decrease in the proportion of methyldopa excreted as "free" methyldopa (49.5% +/- 12.4% vs 21.1% +/- 4.77%; p less than 0.01), a significant increase in the proportion excreted as methyldopa sulfate (37.8% +/- 12.3% vs 65.8% +/- 10.5%; p less than 0.01), and a decrease in the percentage of methyldopa absorbed (29.1% +/- 12.5% vs 7.88% +/- 4.14%; p less than 0.01). These factors resulted in an 88% reduction in the quantity of "free" methyldopa excreted. To determine if an iron preparation without sulfate produced the same effect, the study was repeated with ferrous gluconate (600 mg) with similar results. The clinical consequences of the methyldopa-ferrous sulfate interaction was determined in five hypertensive subjects receiving chronic methyldopa therapy. The subjects took ferrous sulfate for 2 weeks. There was an increase in both systolic and diastolic blood pressure in four patients and a decrease in blood pressure in all patients after ferrous sulfate was discontinued. The increases in blood pressure were substantial in three of the patients.

Administration, Oral↗
PubMed1987

Outcome in infants of birth weight 500 to 999 g: a continuing regional study of 5-year-old survivors.

During 1979 and 1980, 351 infants of birth weight 500 to 999 g were born in the State of Victoria: 89 (25.4%) survived to the age of 2 years corrected for prematurity, and 83 were fully assessed by a multidisciplinary team; partial data were obtained on the remainder. At the age of 5 years, corrected for prematurity, 85/89 (96%) were evaluated by a multidisciplinary team, although not all children could be fully evaluated by the psychologists. Reports were available for another three children; one child was untraced. Of the survivors able to be classified at 5 years, 59/82 (72%) had no functional handicap. Functional handicaps was severe in 16 (19%), moderate in four (5%), and mild in three (4%). Functional handicaps were present in 50% (8/16) of outborn survivors compared with the 23% (15/66) for the inborn survivors (P = 0.02). Cerebral palsy was diagnosed in eight children at 5 years and in 12 children at 2 years. The diagnosis was stable for the children not ambulant at 2 years; five of seven 2-year-old children with mild cerebral palsy had "outgrown" the diagnosis by 5 years, but ataxic cerebral palsy was not identified in one child until 5 years. Six children were blind; four had severe sensorineural or mixed deafness, one more than at 2 years. Of 82 children assessed according to identical criteria for functional handicap at both 2 and 5 years, 52 (63%) remained in the same category at 5 years, three (4%) were judged to be more severely handicapped, and 27 (33%) were less severely handicapped. The 2-year evaluation of extremely low birth weight children often proved to be unduly pessimistic, for many showed improvement or recovery from functional handicaps and impairments by 5 years of age.

Australia↗
PubMed1986

Interaction between Aeromonas salmonicida and peritoneal macrophages of brook trout (Salvelinus fontinalis).

The phagocytic and bactericidal properties of peritoneal macrophages obtained from brook trout (Salvelinus fontinalis), injected with either glycogen or a modified Freund's complete adjuvant (MFCA), were evaluated against an avirulent and a virulent strain of Aeromonas salmonicida. Avirulent bacteria were effectively phagocytized and killed by macrophages obtained from fish injected with both irritants. With glycogen-elicited macrophages, no enhancement of killing was observed following opsonization of avirulent bacteria with specific antibodies. A killing index (K.I.) of 38 was obtained, compared to a K.I. of 39 for unopsonized bacteria. When avirulent bacteria were opsonized with complement, the K.I. was increased to 67. Virulent bacteria were less susceptible to the phagocytic and the bactericidal activities of glycogen-elicited macrophages, even after opsonization with antibodies and/or complement, K.I. of 9 to 15. In contrast, MFCA-elicited macrophages showed increased phagocytic and bactericidal activities against both strains. The K.I. of unopsonized virulent bacteria was increased to 47 and 46 compared to K.I. of 4 and 7 obtained with glycogen-elicited macrophages.

Aeromonas↗
PubMed1984

Outcome in infants with birth weight 500 to 999 gm: a regional study of 1979 and 1980 births.

During 1979 and 1980, 351 infants weighing 500 to 999 gm were born in the State of Victoria, Australia; 89 (25.4%) survived to 2 years of age. Survival was better for tertiary center births (29%) than for those born elsewhere (17%). Multidisciplinary teams reviewed 83 of the survivors at 2 years of age postterm; some data were available for the other six children. Overall, 22.5% of infants had severe functional handicap, 29.2% had either moderate or mild handicap, and 48.3% had no handicap. Severe functional handicap was present in 50% of outborn infants; this was significantly more common than in those born in tertiary centers (15.5%), and the Bayley Mental Developmental Index was also significantly lower in outborn infants. The prevalence of cerebral palsy (13.5%), bilateral blindness (3.4%), and severe sensorineural deafness (3.4%) did not differ significantly in the inborn and outborn infants. Singleton inborn infants of appropriate weight for gestational age had significantly less severe functional handicap (9.1%), compared with 37.5% for the group of infants who were either small for gestational age or one of multiple births. Six of the 18 outborn infants could have been transferred in utero, and improvements in immediate neonatal care were possible in seven other infants.

Age Factors↗
PubMed1984

Outcome of extremely low birth-weight infants in relation to the hospital of birth.

There were 351 liveborn infants of birth-weight 500-999 g born in the State of Victoria in the years 1979 and 1980; 89/351 (25.4%) survived to the age of 2 years: 42 (47.2%) survivors were of gestational ages of 24 to 26 weeks and 47 (52.8%) were born at 27 to 32 weeks' gestation. Survival of these extremely low birth-weight infants was significantly better (71/245, 29%) for births in tertiary centres compared with those born elsewhere (18/106, 17%). Of the 351 livebirths, 69.8% occurred in 1 of the 3 tertiary centres. All 89 survivors were traced; 84 (94.4%) were assessed at the age of at least 2 years by a multidisciplinary team. Three children had been fully assessed at 1 year of age and paediatric reports were available for 2 children. The quality of survival of children born in tertiary centres was significantly better than those transferred to a tertiary centre after birth; the prevalence of serious functional handicap was 72.2% (13/18) for outborn children compared with 22.5% (16/71) for those born in tertiary centres. The prevalence of serious functional handicap in the inborn survivors was lowest (9/55, 16.4%) in singleton births who had been of appropriate birth-weight for gestation. A review of the 18 surviving outborn infants' records indicated that 6 (33.3%) could have been transferred to a tertiary centre in utero and for the 12 infants where birth in a tertiary centre was not feasible, improvements in the early neonatal care were possible in another 7 infants.

Australia↗
PubMed1984

Dynamics of Listeria monocytogenes type 4b infection in pregnant and infant rats.

In order to examine the dynamics of perinatal listeriosis, we established a rat model of infection using a strain of Listeria monocytogenes type 4b isolated from a human newborn infant. When injected subcutaneously, the median lethal dose (LD50) to the organism was lower for pregnant than nonpregnant animals (10(8) vs 10(9) colony forming units [cfu]). Susceptibility was greatest on the 16th day of gestation (67% mortality) as was the likelihood that the offspring had generalized infection (50%). In contrast, all five pregnant rats injected on the 9th day of gestation survived. None of the five went on to have a litter, thus suggesting that there was intrauterine death. The LD50 for infant (3-day-old) rats was 6 X 10(5) cfu; that for juveniles (13-day-old) 2.5 X 10(7) cfu (p less than 0.005). No differences were seen between infant or juvenile rats in the number of viable bacteria in homogenized liver, spleen and lung or in blood at 1 or 3 days after a weight-adjusted intraperitoneal bacterial challenge. However, 5 days after challenge, viable organisms were decreased in all of these sites for the juveniles while they were increased for the infants (p less than 0.001). Polymorphonuclear (PMN) and mononuclear cells appeared in the peritoneum in similar concentrations for infant and juveniles one day after intraperitoneal challenge. At 5 days the number of mononuclear cells was significantly greater for juveniles compared to infants (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1983

Provision of perinatal services and survival of extremely low birthweight infants in Victoria.

The transfer of at-risk mothers to one of the three Level III maternity hospitals in Victoria has been promoted since 1975; since 1978, the Newborn Emergency Transport Service has been available throughout the State for the transport of infants to the four Level III neonatal units. By means of data from multiple sources, we ascertained the one-year survival of infants with birthweights of between 500 g and 999 g born in Victoria between 1978 and 1981. Of 711 live-born infants, 227 (31.9%) survived 28 days and 210 (29.5%) lived to at least one year of age; of 490 infants born in the Level III maternity units, 156 (31.8%) lived. There were 54 (24.4%) survivors among the 221 infants born elsewhere; all these survivors were included in the group of 105 babies who had been transferred after birth to Level III neonatal units. Although only 25.5% of all births for the State occurred in the Level III maternity hospitals, 69% of all infants who weighed between 500 g and 999 g at birth were delivered in these hospitals. The transfer of the mother or the new born baby to a Level III unit was possible in an additional 48 cases. Although survival rates from Level III hospitals may possibly improve in the future, the shortage of ventilator beds remains a practical obstacle.

Australia↗
PubMed1983

Eating as a function of body weight and of hours deprivation.

Five pigeons were allowed one hour of access to food after variable intervals of deprivation averaging 23 hours. Five other pigeons were allowed one hour of food after fixed 23 hour intervals. It was found that the amount eaten by birds in an environment continually alternating between deprivation and one-hour ad lib feeding could be better predicted as a linear function of their body weights than as a 2nd degree polynomial function of the number of hours they were deprived.

Animals↗
PubMed1983

Risk factors in phenytoin-induced gingival hyperplasia.

A survey was carried out into the degree of gingival hyperplasia in 68 patients receiving phenytoin in a hospital for the mentally handicapped. Comparisons of degree of gingival hyperplasia exhibited by the patients were made with a range of parameters by analysis of variance and Chi square tests. The severity of the hyperplasia increased with increasing dose, increasing dose per unit body weight and serum levels of phenytoin and also with decreasing age and weight of the patients. No significant relationship (P less than 0.2) was found between serum folate levels and degree of hyperplasia. Poor oral hygiene predisposed patients to hyperplasia.

Adolescent↗
PubMed1982

Potassium conservation with amiloride/hydrochlorothiazide ("Moduret') in thiazide-induced hypokalaemia in hypertension.

A double-blind study was carried out in 24 hypertensive patients with thiazide-induced hypokalaemia (serum potassium less than 3.2 mmol/l) to compare the effects of treatment with an amiloride/hydrochlorothiazide combination or hydrochlorothiazide alone. The study was divided into three phases: (i) potassium repletion (Weeks 0 to 4) with oral potassium chloride (40 mmol/day), (ii) stabilization (Weeks 4 to 6) of normokalaemia, and (iii) active drug treatment (Weeks 6 to 14), patients being allocated at random to receive one or other of the two treatments. Dosage was 2 tablets per day of the 5 mg amiloride plus 50 mg hydrochlorothiazide combination or of 50 mg hydrochlorothiazide alone. The results showed that blood pressure control was comparable in both treatment groups but hydrochlorothiazide alone caused a statistically significant reduction in serum potassium levels compared to the drug combination. Apart from 1 patient who developed hypokalaemia on hydrochlorothiazide alone, no other side-effects of treatment were reported.

Amiloride↗
PubMed1981

Effect of cooking and cold storage on biologically active antibiotic residues in meat.

An investigation was undertaken to see if cooking or cold storage would destroy or decrease the level of biologically active antibiotic in tissues from animals given therapeutic doses of antibiotic on three occasions prior to slaughter. The effects of cooking and cold storage on the biological activity of the residues of ampicillin, chloramphenicol, oxytetracycline, streptomycin and sulphadimidine were varied; in some instances the effects were minimal, in others nil.

Animals↗