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Biomedical subjects

G Barker

Publications and source records attributed to G Barker.

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

Ventilatory predictors of pulmonary hypoplasia in congenital diaphragmatic hernia, confirmed by morphologic assessment.

We carried out a prospective study in 66 infants with congenital diaphragmatic hernia within the first 6 hours of life to determine whether outcome is related to the degree of underlying pulmonary hypoplasia, as predicted by preoperative PaCO2, when correlated with an index of ventilation (VI = mean airway pressure X respiratory rate) and confirmed by postmortem analysis of the lung. Those infants with PaCO2 greater than 40 mm Hg before surgery had a 77% mortality; when PaCO2 reduction could be achieved only with VI greater than 1000, the mortality was still greater than 50%. After repair, however, the ability to hyperventilate to PaCO2 less than 40 mm Hg proved to be an important determinant of survival; only one of 31 infants in this group died, whereas only two of 27 infants with PaCO2 greater than 40 mm Hg survived. In 16 infants with PaCO2 greater than 40 mm Hg despite hyperventilation, high-frequency oscillatory ventilation was started. This resulted in a rapid fall in PaCO2, but 14 of the 16 infants had only temporary improvement in oxygenation, and died. In five of the infants who died, alveolar number was assessed by postmortem morphometric analysis; there was a severe reduction to less than 10% of published normal neonatal values. Pulmonary vascular changes of increased muscularization were less remarkable than those observed in infants with persistent pulmonary hypertension. Our findings suggest that the degree of pulmonary hypoplasia (which would not be influenced by surgical repair), rather than the pulmonary vascular abnormality, mainly determines survival. Consideration could therefore be given to an initial nonsurgical approach to congenital diaphragmatic hernia, with the expectation that pulmonary function might improve and pulmonary vascular resistance decrease.

Hernia, Diaphragmatic↗
PubMed1987

Treatment of the unstable bladder with propantheline and imipramine.

This study shows propantheline and imipramine to be effective in the management of the unstable bladder. It emphasizes the need for urodynamic studies for the accurate diagnosis of urinary incontinence. Comparisons have been made of the efficacy of propantheline and imipramine in various groups of incontinent women and indicates that in appropriately selected groups the 'cure' rate is over 70% but if sphincter weakness is excluded, urodynamics cannot differentiate between those women with unstable bladders who will respond to this medication and those who will not.

Drug Therapy, Combination↗
PubMed1986

A prospective randomized trial comparing high-dose cisplatin with low-dose cisplatin and chlorambucil in advanced ovarian carcinoma.

Sixty-one patients with FIGO stage III ovarian carcinoma and 30 patients with stage IV ovarian carcinoma were randomized to receive either high-dose cisplatin (100 mg/m2) or low-dose cisplatin (20 mg/m2) and chlorambucil. Overall response rates were similar in both arms, with 68% and 49% of stage III patients and 61% and 72% of stage IV patients responding to high-dose cisplatin and the combination, respectively. There was a strong trend for better survival in stage III (P less than .05) but not in stage IV patients treated with cisplatin alone. The toxicity suffered by patients treated with high-dose cisplatin was severe, and in 15 patients cisplatin therapy was stopped because of unacceptable toxicity.

Actuarial Analysis↗
PubMed1985

Effects of mechanical ventilation on cardiopulmonary function in children after open-heart surgery.

The reduction in functional residual capacity (FRC) after anesthesia and thoracic surgery may result in atelectasis, hypoxia, and respiratory failure. Mechanical ventilation reverses the FRC reduction but may also decrease cardiac output and increase the pulmonary vascular resistance index (PVRI) in some patients. The cardiopulmonary effects of stopping mechanical ventilation after open-heart surgery were studied in 17 children. FRC, arterial pH, and PaO2 were significantly reduced, while PaCO2, oxygen consumption, and right ventricular stroke work index significantly increased. Mean FRC on spontaneous respiration was below normal despite continuous positive airway pressure. PVRI increased significantly in patients whose FRC fell below 22 ml/kg on spontaneous respiration. The PVRI increase was most marked in patients with pre-existing pulmonary vascular disease. These results confirm the value of appropriate mechanical ventilation in the early postoperative management of children undergoing open-heart surgery, particularly those with pulmonary vascular disease.

Cardiac Output↗
PubMed1984

Intravenous salbutamol in the treatment of status asthmaticus in children.

The management of status asthmaticus using a continuous iv infusion of salbutamol was studied in 14 children with a total of 16 episodes of respiratory failure, unresponsive to conventional bronchodilator therapy. The mean PaCO2 at the start of the infusion was 60 +/- 6 torr. A loading dose of 1 microgram/kg X min body weight was given over 10 min, followed by an infusion of 0.2 microgram/kg X min which was increased in 0.1-microgram/kg steps according to response. The maximum dose was 4 microgram/kg X min. On 11 (69%) occasions a sustained reduction in PaCO2 was achieved within 4 h of starting the infusion. In 5 (11%) instances no reduction in PaCO2 was seen and mechanical ventilation was instituted because of increasing respiratory distress and CO2 retention. Mean heart rate during the infusion increased from 161 to 183 beat/min. Comparison with previous data from 30 pediatric patients (40 infusions) receiving iv isoproterenol showed less effect on heart rate and a more sustained fall in PaCO2 without the recurrence of bronchospasm. We found salbutamol to be a safe and effective bronchodilator capable of reversing severe bronchospasm in most children who would otherwise require mechanical ventilation. Its greater specificity for beta 2-receptors may make it preferable to isoproterenol.

Adolescent↗
PubMed1984

Steroid hormone receptors in the female lower urinary tract.

The preliminary results of a study to estimate the level of cytosol oestrogen and progesterone receptors in the lower urinary tract are presented. 29 full thickness biopsies were obtained from the vault, trigone and urethra of 9 female surgical patients aged 13-72 years. Cytosol assay for oestradiol-17 beta receptors and progesterone receptors was performed. Oestrogen receptors were present in all 5 urethral specimens examined and with a consistently higher concentration in the middle and distal thirds in comparison to the proximal urethra. In only 1 of the 9 vault specimens and 8 trigone specimens were receptors found and those in small quantities. No progesterone receptors were determined in any of the vault, trigone and urethral specimens examined. The presence of oestrogen receptors in the middle and distal thirds of the human female urethra is strong supportive evidence of the sensitivity of the urethra to oestrogens, and the higher concentration of those receptors in these sites in comparison to the proximal urethra, vault and trigone confirms the common embryological origin of the distal urethra and vagina from the definitive urogenital sinus. The absence of measurable progesterone receptors in all the lower urinary tract specimens examined is discussed.

Adolescent↗
PubMed1983

Ectopic production of human chorionic gonadotrophin (hCG) and human placental lactogen (hPL) by ovarian carcinoma.

Human chorionic gonadotrophin (hCG) and human placental lactogen (hPL) are placental proteins whose ectopic secretion by non-trophoblast tumours has been claimed to be of clinical relevance. Radioimmunoassays for hCG and hPL, together with human luteinising hormone (hLH), have been established and plasma levels were measured in 61 patients with carcinoma of the ovary. Approximately 51% of the patients were found to have raised plasma hCG levels. Such raised titres were not stage or tumour-type related but occurred only in post-menopausal subjects. The majority of patients with raised hCG levels also had raised plasma hLH levels. Assay cross-reactivity was shown to account for the 'spurious' hCG elevations. However, hCG may be an ectopic product in a minority of tumours; elevated plasma hCG levels were shown to coexist with low hLH levels. Although such lesions did not show morphologically identifiable choriocarcinomatous elements, all were poorly differentiated carcinomas. In some cells hCG was demonstrated by immunocytochemical methods. No patients had a raised plasma hPL level. It is concluded that these placental proteins are of no clinical use in the management of ovarian carcinoma patients.

Adult↗
PubMed1982

A typology for the classification of disasters: implications for intervention.

A model that can be used to plan for disaster intervention services is presented. The model, which is based upon an ability to classify disasters, presents four dichotomous categories for intervention: (1) psychotherapeutic vs. educational, (2) individual vs. systems, (3) prevention vs. treatment, and (4) direct vs. indirect. The article presents a rationale for determining which intervention, or combination, would be appropriate for any given disaster, based on its classification.

Adaptation, Psychological↗
PubMed1981

Identification of two strains of cultured canine renal epithelial cells (MDCK cells) which display entirely different physiological properties.

Cultured monolayers of Madin-Derby canine kidney (MDCK) cells grown upon permeable filter supports display many features of in vivo epithelia. Measurements of transmonolayer resistance, open-circuit p.d., dilution and bi-ionic p.d.s have been made of MDCK monolayers mounted in Ussing-type chamber (0.75 cm window radius). Previously reported values of transmonolayer resistance of 100 omega cm2 (Cereijido, Robbins, Dolan, Rotunno & Sabatini, 1978; Misfeldt, Hamamoto & Pitelka, 1976) indicate a 'leaky' epithelium. The major finding of this work is that MDCK monolayers can also display values of transmonolayer resistance similar to 'tight' epithelia (mean value = 4116 omega cm2). The reason for such differences is the existence of separate strains of MDCK cells. High-resistance monolayers originate from cell stocks of sixty serial passages whilst low-resistance monolayers originate from cell stocks of 109 serial passages. Measurements of transmonolayer dilution, and bi-ionic p.d.s together with Na ion tracer fluxes and electron microscope observations of La3+ penetration through the apical tight junctions, substantiate the finding of high-resistance properties in MDCK monolayers and confirm the existence of two separate MDCK cell strains displaying entirely different physiological properties. Differences extend to cellular morphology and cellular volume in the two strains of MDCK cells.

Animals↗
PubMed1980

The pharmacologic treatment of newborn diaphragmatic hernia--a 2-year evaluation.

From 1968 to 1976 inclusive, 69 neonates with diaphragmatic hernias had corrective surgery within 18 hr of birth and the survival rate was 41%. During the same time, all babies with similar hernias who were operated on later than 18 hr from the time of birth survived. Our present interest has been focused on the pulmonary artery and its hypertension with the subsequent development of right to left shunting through the patent ductus arteriosus. During 1977 and 1978, we attempted to enter 19 consecutive newborns 18 hr of age or less with symptomatic Bochdalek diaphragmatic hernias into a "Collins protocol" for treatment. This included four stages: newborn nursery initial resuscitation, operation, cardiac catheterization, and ICU monitoring and pharmacological therapy. There was a total of seven survivors (36%), however for a number of reasons only eight babies really had a complete entry into this protocol and of these eight, five survived. Although this study is far from complete, some initial information and concepts are forthcoming. It is now apparent to us that there are three distinct groups into which these very early newborns fall: minimal pulmonary hypoplasia, unilateral hypoplasia and bilateral hypoplasia. The first group probably does not need pharmacologic support, while in the last it probably does not help. Further interest in other more specific pulmonary pharmacologic agents is now being considered as well as some way of early recognition of which baby is going to fit into which group, so that only the ones that need this treatment will get it.

Acetylcholine↗
PubMed1976

Nursing deans as leaders in collegiate health professions.

Deans of Nursing who choose to be administrators of the Health Sciences may very well enhance Nursing programs by facilitating the nursing faculty to become leaders through offering service courses in Health, may thereby help to cut the high cost of nursing education, and may make a contribution to other Health majors by sharing their faculty's special expertise in Health theory.

Chemistry, Clinical↗