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Biomedical subjects

K Street

Publications and source records attributed to K Street.

13 recordsLinked to original sources
PubMed2004

How great is the risk of abuse in infants born to drug-using mothers?

UNLABELLED: This prospective, cohort study reports early child protection and surveillance process markers for children born to self-proclaimed drug-using mothers. BACKGROUND: A strong association is reported between maternal drug use and child abuse in North American studies. There are no systematic data describing this association for the UK population. Given the heterogeneous nature of drug cultures and associated behaviour it is difficult to generalize from US data to the UK population. METHODS: The study group consisted of all women referred to a hospital-based antenatal clinic for pregnant drug users. Infants of non-drug users were matched for social class and gestational age. At 18 months the Bristol and surrounding area child protection registers and child health surveillance records were searched. Infants were coded as to whether they were the subject of an enquiry, case conference, registration, registration with subsequent deregistration, or taken into care. RESULTS: There were 68 infants of drug users and 127 infants of non-drug users. Most (81%) of drug users were heroin and/or methadone users; half were using/had used intravenously. Child health surveillance uptake for both groups is lower than that reported for the Avon population as a whole during the study period, consistent with the relatively deprived populations represented. There is no statistically significant difference between the drug users and non-drug users. The overall risk of child protection proceedings was higher in children of drug users than in children of non-drug users. However, closer inspection of the data shows most of the excess risk is explained by the small group taken into care and the much larger group for whom the concerns were relatively shortlived as shown by their subsequent deregistration during the study period. CONCLUSIONS: Maternal drug use does not necessarily lead to unacceptable standards of parenting. More UK-based research is needed to inform the risk assessment process for child protection.

Child Abuse↗
PubMed2000

The decision making process regarding the withdrawal or withholding of potential life-saving treatments in a children's hospital.

OBJECTIVES: To investigate the factors considered by staff, and the practicalities involved in the decision making process regarding the withdrawal or withholding of potential life-sustaining treatment in a children's hospital. To compare our current practice with that recommended by the Royal College of Paediatrics and Child Health (RCPCH) guidelines, published in 1997. DESIGN: A prospective, observational study using self-reported questionnaires. SETTING: Tertiary paediatric hospital. PATIENTS AND PARTICIPANTS: Consecutive patients identified during a six-month period, about whom a formal discussion took place between medical staff, nursing staff and family regarding the withholding or withdrawal of potentially life-sustaining treatments. The primary physician and primary nurse involved in the discussion were identified. METHOD: Two questionnaires completed independently by the primary physician and nurse. RESULTS: Twenty-two patients were identified (median age 1 year; range 1 day-34 years). In 20 cases treatment was withdrawn or withheld, in two cases treatment was continued. Nursing staff considered family wishes and family perceptions of patient suffering as significantly more important factors in decision making than medical staff, who considered prognostic factors as most important. In only two cases were the patient's expressed wishes apparently available. In most cases staff considered the patient's best interests were served and the process would not be enhanced by the involvement of an independent ethics committee. The exceptions were those cases in which treatment was continued following disagreement between parties. CONCLUSIONS: Our current practice is consistent with that recommended by the RCPCH. The contribution of the patient, provision of staff counselling and general practitioner (GP) involvement were identified as areas for improvement.

Child↗
PubMed1997

Calcium concentration-dependent mechanisms through which ketamine relaxes canine airway smooth muscle.

BACKGROUND: Ketamine is a potent bronchodilator that, in clinically used concentrations, relaxes airway smooth muscle in part by a direct effect. This study explored the role of calcium concentration (Ca2+) in this relaxation. METHODS: Canine trachea smooth muscle strips were loaded with the fluorescent probe fura-2 and mounted in a spectro-photometric system to measure force and intracellular calcium concentration ([Ca2+]i) simultaneously. Calcium influx was estimated using a manganese quenching technique. Cyclic nucleotides in the airway smooth muscle strips were measured by radioimmunoassay. RESULTS: In smooth muscle strips stimulated with submaximal (0.1 microM) and maximal (10 microM) concentrations of acetylcholine, ketamine caused a concentration-dependent decrease in force and [Ca2+]i. The sensitivity of the force response to ketamine significantly decreased as the intensity of muscarinic receptor stimulation increased; the median effective concentration for relaxation induced by ketamine was 59 microM and 850 microM for tissue contracted by 0.1 microM or 10 microM acetylcholine, respectively (P < 0.05). In contrast, the sensitivity of the [Ca2+]i response did not depend on the intensity of muscarinic receptor stimulation. Ketamine at 1 mM significantly inhibited calcium influx. Ketamine did not significantly increase cyclic nucleotide concentrations. CONCLUSIONS: Ketamine-induced relaxation of canine airway smooth muscle is associated with a decrease in [Ca2+]i and calcium influx, effects that are not mediated by an increase in cyclic nucleotides; and the sensitivity of the force response to ketamine decreases as the level of preexisting muscle tone increases, an effect that is not explained by differential effects on [Ca2+]i.

Anesthetics, Dissociative↗
PubMed1994

Studies of tamoxifen as a promoter of hepatocarcinogenesis in female Fischer F344 rats.

Tamoxifen, an antiestrogen used in the treatment of breast cancer, was assessed for carcinogenic potential in the two-stage model of experimental hepatocarcinogenesis. Groups of female Fisher F344 rats were initiated with a non-necrogenic, subcarcinogenic dose of diethylnitrosamine (DEN; 10 mg/kg, po) and fed tamoxifen at a concentration of 250 mg per kg of AIN-76A diet for 6 or 15 months. The livers of these animals exhibited an increase in size and number of altered hepatic foci compared with those animals which were initiated with DEN but not exposed to tamoxifen. This finding indicates that tamoxifen may have a carcinogenic potential in the rat liver. After 6 months of treatment, neoplastic nodules were observed in 3/8 rats in the DEN-initiated, tamoxifen-treated group. In the initiated group provided with tamoxifen for 15 months, neoplastic nodules were observed in 7/8 rats and hepatocellular carcinomas in 3/8 rats. The serum level of tamoxifen in these rats was 200-300 ng/ml. The ratio of tamoxifen, 4-hydroxy tamoxifen, and N-desmethyl tamoxifen was 1:0.1:0.5-1 in the serum. When adjusted for age-related weight increases, the serum and liver levels of tamoxifen and its N-desmethyl metabolite did not change over the 15 months. In the rat liver, the level of tamoxifen and its N-desmethyl metabolite was 10-29 micrograms/g liver after 6 or 15 months of chronic dietary administration. The ratio of tamoxifen:4-hydroxy tamoxifen:N-desmethyl tamoxifen was 1:0.1.3-3.3 in the liver. Therefore, the liver had 20- to 30-fold more tamoxifen and 4-hydroxy tamoxifen and at least 100-fold more N-desmethyl tamoxifen than the serum (assuming 1 gram of tissue is equivalent to 1 ml of serum). These results indicate that tamoxifen is a promoting agent for the rat liver at serum levels found in patients given the usual therapeutic course of tamoxifen. The high concentrations of tamoxifen attained in the rat liver indicate that actions other than its known estrogenicity for liver could contribute to its promoting action. In addition, these results indicate that the pharmacodynamic differences in tamoxifen metabolism in rats and humans and at low versus high doses should be determined. Thus, the therapeutic indications for tamoxifen should be balanced by the potential risk it may present as a promoting agent in mammalian liver.

Animals↗
PubMed1994

A comparison of the brain weights of normal, untreated hydrocephalic and treated hydrocephalic rat pups.

The dry brain weights of normal, untreated and treated hydrocephalic pups of Texas, Lewis and Texas/Lewis cross rats aged from 2 to 60 days were compared using the technique of generalised linear modelling. It was found that with increasing age there is a steadily progressive increase in the weight of the brains of the normal animals. The brains of the untreated hydrocephalics showed a normal increase in weight up to about the 25th day but after that whilst the weight continued to increase, it was significantly less than normal. On the other hand the weight gain of the brains of the treated hydrocephalic pups resembled that of the normals and steadily increase in weight throughout the period of observation.

Animals↗
PubMed1987

Double-blind comparison of half-dose and standard-dose flupenthixol decanoate in the maintenance treatment of stabilised out-patients with schizophrenia.

A double-blind controlled trial of 50% dose reduction in maintenance treatment in stable out-patients with low BPRS scores and good social function shows a significantly higher relapse rate in the low-dose group at 12 months (P less than 0.05). After an interval of 24-36 months from dose reduction, 56-76% had experienced a relapse and 76-79% had resumed their former dosage. No clear advantage was shown for the lower dose in either a reduction of side-effects or improved social function, but a reduced prevalence or lower rate of symptom emergence for tardive dyskinesia was suggested.

Adult↗
PubMed1983

The discontinuance of maintenance neuroleptic therapy in chronic schizophrenic patients: drug and social consequences.

In a prospective follow-up the outcome of 60 chronic schizophrenic patients who discontinued neuroleptic therapy after remaining stable 12-48 months was compared with controls continuing medication. Not only did the drug-discontinued patients have more relapses (P less than 0.001), but the form of relapse was both more severe and acute, resulting in differences of self-injury (P less than 0.05), anti-social behaviour (P less than 0.01), inpatient admissions (P less than 0.001), and the use of compulsory powers (P less than 0.01). In patients who relapsed, both social and work function was affected adversely for some months. Patients who remained relapse-free without drugs (20%) had a level of work and social function similar to medicated patients. At the end of 18 months the patients who discontinued depot maintenance therapy were found to have been prescribed one-third more neuroleptic drugs than controls, with a possible increase in the risk of long-term tardive dyskinesia.

Adult↗