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Biomedical subjects

M King

Publications and source records attributed to M King.

At least 253 records · Page 14Linked to original sources
PubMed1992

Is there a seasonal variation in mucus transport and nutrient absorption in the leopard frog?

We postulated that as a hibernating species, frogs might have variable demands for nutrients at different seasons of the year and that this must be reflected in seasonal variations of physiologic processes related to nutrient transport and absorption. We examined the rate of mucus transport on the ciliated palate and the movement of nutrients across the intestinal lumen of leopard frogs, Rana pipiens. Mucus transport on the frog palate was strongly influenced by season, with maximal transport occurring in late June (Julian day 178, p = 0.0001; r = 0.58). This increased transport rate was associated with a summertime increase in mucus recoil (lower tangent delta) and a decrease in mucus hydration (increase in percent solids composition). Intestinal transport of leucine, lysine, and galactose did not appear to exhibit seasonal variability. These data suggest that different mechanisms may operate in determining seasonal variability in physiologic responses.

Animals↗
PubMed1992

Respiratory mucus from asymptomatic smokers is better hydrated and more easily cleared by mucociliary action.

We compared the physical and transport properties of tracheal mucus collected from 16 asymptomatic smokers and from 18 nonsmokers. The smokers produced a larger volume of mucus (wet weight 18.6 versus 11.2 mg; p = 0.04) with a lower solids content (11.5 versus 16.3%; p = 0.02) and a lower modulus of rigidity (log G* 2.37 versus 2.62; p = 0.04). Although the smokers mucus had a 40% faster mucociliary transport rate on the frog palate (p = 0.04), the cough clearability was nearly identical to the mucus from nonsmokers. The differences are similar to those observed in rats or dogs chronically exposed to cigarette smoke. These data suggest both a quantitative and a qualitative difference in the composition of mucus from asymptomatic smokers. The increased volume of a watery mucus with increased mucociliary clearability may help to protect the airways from the injurious effects of inhaled smoke.

Adult↗
PubMed1992

Homosexuals who are twins. A study of 46 probands.

Forty-six homosexual men and women who were twins took part in a study of their sexuality and that of their co-twin. Discordance for sexual orientation in the monozygotic pairs confirmed that genetic factors are insufficient explanation of the development of sexual orientation. There was a high level of shared knowledge of sexual orientation between members of twin pairs, and a relatively high likelihood of sexual relations occurring with same sex co-twins at some time, particularly in monozygotic pairs. The implications of these results for the study of the origins of sexual orientation and for twin research are discussed.

Adolescent↗
PubMed1992

Mucus rheology and transport in neonatal respiratory distress syndrome and the effect of surfactant therapy.

BACKGROUND: Neonatal respiratory distress syndrome (RDS) is caused by a deficiency of pulmonary surfactant. Alveolar collapse and obstruction of conducting airways leads to mismatch of ventilation and perfusion and profound hypoxemia. We postulated that surfactant deficiency could alter the properties of respiratory mucus in such a way that it would be poorly cleared from airways and promote airway luminal obstruction and that these changes might be reversed by the exogenous administration of a synthetic surfactant preparation. METHODS: Respiratory mucus coating an endotracheal tube (ETT) or suction catheter was collected from 14 neonates (gestational age, 24 to 36 weeks; birth weight, 600 to 2,400 g) with RDS who required tracheal intubation and ventilation. Eight of these neonates received 5 ml/kg of an intratracheal artificial surfactant preparation (Exosurf), given between 2 and 10 h of age and six neonates received 5 ml/kg of air. Mucus viscoelasticity, hydration (percentage of solid composition of mucus), and mucociliary clearability (NFPTR) were measured for each specimen. RESULTS: The total volume of mucus collected from the surfactant-treated and control infants was similar, but mucus hydration was significantly less in babies with RDS who did not receive Exosurf (percentage of solid composition of mucus 18.7 vs 11.4; p = 0.013). Ciliary transportability was also less in the untreated babies (NFPTR 0.39 vs 0.86; p = 0.018) and this mucus was more rigid (increased viscoelasticity: log G* 1 rad/s 2.28 vs 1.50; p = 0.0001). CONCLUSIONS: These data suggest that airway obstruction in RDS may be due, in part, to abnormal mucus properties and impaired ciliary transport. Surfactant therapy appears to improve mucus clearability. Exogenously administered surfactant may also be beneficial for the treatment of other selected respiratory conditions associated with impaired mucus clearance.

Drug Combinations↗
PubMed1992

Trends in tans and skin protection in Australian fashion magazines, 1982 through 1991.

We rated 3971 photographs of models from midsummer editions of six Australian fashion magazines from 1982-1983 to 1990-1991 for tan on a 9-point scale, for the presence of hats, for sun-protective clothing, and for shade setting. With the exception of the 1990-1991 sample, there was an increasing proportion of light tans over the years. Men were more likely to be deeply tanned than were women. The proportion of models wearing hats followed an increasing linear trend across the five periods. Three quarters of the outdoor photographs were taken in unshaded settings. In unshaded settings, 17% of the women and 5% of the men wore hats.

Australia↗
PubMed1992

Intrapartum asphyxia in term and post term infants.

Many attempts have been made to identify infants at risk of suffering asphyxial brain damage. In a retrospective review of records at the Rotunda Hospital over a five year period all infants who died or suffered seizures, presumed secondary to asphyxia, were compared with the general hospital population. Out of 28,655 deliveries reviewed, there were 13 deaths in infants at or after term associated with perinatal asphyxia, and 32 surviving infants had asphyxial seizures. Seizures were regarded as asphyxial in origin if they occurred in the first forty eight hours of life and were associated with other clinical evidence of asphyxia. The incidence of abnormal presentations, assisted breech deliveries, instrumental deliveries and emergency caesarean sections was all increased in the asphyxial categories compared to the control population. Referral to the fetal assessment unit was associated with a seizure rate of 0.16/1000 live births compared with a rate of 1.4/1000 in the remaining non referred hospital population. Nineteen percent of the infants who seized subsequently developed cerebral palsy. It would appear from our data that referral to the fetal assessment unit and the consequent assignment to "high risk" status is associated with low risk in terms of asphyxial outcome.

Asphyxia Neonatorum↗
PubMed1992

Phase II evaluation of iproplatin in patients with advanced gastric and pancreatic cancer.

A total of 48 patients with measurable advanced gastric adenocarcinoma (n = 16) or adenocarcinoma of the exocrine pancreas (n = 32) were prospectively treated with iproplatin at a starting dose of 270 mg/m2 intravenously over 2 hours. The dose was repeated every 28 days, and dose escalations or reductions were made on the basis of toxicity in the preceding course. No patient with gastric carcinoma achieved either a complete or partial response. One partial response and two complete responses were seen with pancreatic adenocarcinoma for an overall response rate of 10%. One patient has remained free of disease for more than 2 years. The major toxicities were granulocytopenia, thrombocytopenia, nausea, vomiting, and diarrhea. All toxicities were reversible upon discontinuation of the drug. On the basis of this trial, we conclude that iproplatin has no substantive activity in advanced gastric or pancreatic carcinomas.

Adenocarcinoma↗
PubMed1992

Does lithium dose prediction improve treatment efficiency? Prospective evaluation of a mathematical method.

An attempt was made to determine whether an algorithm for lithium dose prediction allows earlier or more economical attainment of a therapeutic steady state than does the usual "clinical titration." Twelve patients were treated using an algorithm developed by Zetin and associates and compared with 21 patients treated by clinical titration. Ten of the 12 algorithm-treated patients (83%) had reached the desired lithium blood level by the seventh day, whereas only 8 of the 21 clinical titration patients (38%) had done so. This difference is significant. In addition, the Zetin algorithm performed safely: the 2 dose prediction errors led to underdosing. Some of the relevant literature is reviewed.

Adult↗
PubMed1992

Characterization of Fc gamma receptors on a human erythroleukemia cell line (HEL).

It has been established that human platelets express a single class of Fc gamma receptors that has been designated Fc gamma RII. However, the function of this receptor on these cells and its regulation are less certain. Studies to further investigate Fc gamma RII on platelets are limited by the inability to culture platelets in vitro. Therefore, identification of a human cell line that expresses Fc gamma RII as its only Fc gamma receptor as well as other platelet characteristics would be of potential importance. To this end, we examined Fc gamma receptor expression by the human erythroleukemia (HEL) cell line, which expresses platelet/megakaryocyte surface proteins. Flow cytometry studies on HEL cells with anti-Fc gamma receptor monoclonal antibodies revealed that, similar to platelets and megakaryocytes, Fc gamma RII is the only Fc gamma receptor expressed on the cell surface. Furthermore, Northern blot analysis revealed that Fc gamma RII is the only Fc gamma receptor mRNA present. Stimulation with dimethylsulfoxide (DMSO) or 12-O-tetradecanoylphorbol-13-acetate (TPA) did not alter Fc gamma RII protein or mRNA expression. Ligand binding studies with [125I]IgG trimer indicated that HEL cells express 92,240 +/- 5030 binding sites per cell, with a kd of 1.94 +/- 0.31 x 10(-8) M. Similar to human platelets, HEL cells preferentially bound oligomeric IgG, and this binding was ionic strength dependent. These observations are similar to those previously observed with Fc gamma RII on human platelets and suggest that the HEL cell Fc gamma receptor is similar, if not identical to the platelet Fc gamma RII receptor. HEL cells may serve as a model for the study of platelet/megakaryocyte Fc gamma RII.

Humans↗
PubMed1991

Recurrent respiratory infections in a child with fucosidosis: is the mucus too thin for effective transport?

Fucosidosis is caused by a deficiency of the lysosomal enzyme alpha-L-fucosidase (ALF) leading to an accumulation of glycoproteins in a variety of cells. Infants and young children with this disorder are prone to recurrent sinus and pulmonary infections and often die of pneumonia. We studied the mucociliary and systemic immune function in a 6 year old girl with fucosidosis and recurrent respiratory infections. All measurements of systemic immune function were normal. Sweat chloride was normal when measured on angiokeratotic skin but was greater than 65 mg/L on uninvolved areas. During the placement of tympanic ventilation tubes, tracheal mucus was gently aspirated and a mucosal biopsy was taken. Tracheal mucus transport was not measured. The biopsy material was examined under phase contrast microscopy and revealed ciliated cells with apparently normal beating. TEM of these cells showed a characteristic pattern of vacuoles in the cytoplasm as described in other tissues from patients with fucosidosis. Ciliary ultrastructure was normal. Mucus viscoelasticity was measured in a magnetic microrheometer. The loss tangent was 2 SD above the mean for normal mucus and mechanical impedance was about 2 SD below the mean. These changes are similar in direction but double in magnitude to what has been described with methacholine administration in dogs. The high compliance of the mucus may be due to incomplete assembly of mucus glycoprotein or to decreased secretion of glycoproteins in respiratory secretions. This leads to mucus that is abnormally watery and thus difficult to clear from the airway.

Child↗