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Biomedical subjects

B Marsh

Publications and source records attributed to B Marsh.

At least 19 recordsLinked to original sources
PubMed1992

A comparison of the pharmacodynamics of rocuronium and vecuronium during halothane anaesthesia.

Thirty healthy patients were randomised to receive either a single bolus dose of rocuronium 0.6 mg.kg-1 or vecuronium 0.1 mg.kg-1 during halothane anaesthesia. Onset time, duration 25, duration 75 and train-of-four 70 were measured. The onset of neuromuscular blockade following rocuronium was more rapid than vecuronium (p = 0.0001). All other pharmacodynamic parameters were similar. During the first minute following injection of the neuromuscular blocking agent, the heart rate increased by 36% in the rocuronium group but remained stable in those patients who received vecuronium (p = 0.0008). No adverse effects were noted in either group.

Adult↗
PubMed1992

Effect of uvulopalatopharyngoplasty on upper airway collapsibility in obstructive sleep apnea.

Previous investigators have demonstrated variable responses to uvulopalatopharyngoplasty (UPP) in patients with obstructive sleep apnea. We hypothesized that this variability is due to either (1) differences in baseline pharyngeal collapsibility preoperatively or (2) differences in magnitude of the decrease in pharyngeal collapsibility resulting from surgery. To determine the relationship between changes in collapsibility and the response to UPP surgery, we measured the upper airway critical pressure (Pcrit) before and after UPP in 13 patients with obstructive sleep apnea. During non-REM sleep, maximal inspiratory airflow (VImax) was quantitated by varying the level of nasal pressure (PN), and Pcrit was determined by the level of PN below which VImax ceased. A positive response to UPP was defined by a greater than or equal to 50% fall in non-REM disordered breathing rate (DBR). In the entire group, UPP resulted in significant decreases in DBR from 71.1 +/- 22.4 to 44.7 +/- 38.4 episodes/h (p = 0.025) and in Pcrit from 0.2 +/- 2.4 to -3.1 +/- 5.4 cm H2O (p = 0.016). Moreover, the percent change in DBR was correlated significantly with the change in Pcrit (p = 0.001). Subgroup analysis of responders and nonresponders demonstrated that significant differences in Pcrit were confined to the responders. Specifically, responders demonstrated a significant fall in Pcrit from -0.8 +/- 3.0 to -7.3 +/- 4.9 cm H2O (p = 0.01), whereas no significant change in Pcrit was detected in the nonresponders (1.1 +/- 1.6 versus 0.6 +/- 2.0 cm H2O. No clinical, polysomnographic, or physiologic predictors of a favorable response were found preoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1991

Pharmacokinetic model driven infusion of propofol in children.

A computer controlled infusion device for propofol was used to induce and maintain general anaesthesia in 20 children undergoing minor surgical procedures. The device was programmed with an adult pharmacokinetic model for propofol. During and after anaesthesia, blood samples were taken for measurement of propofol concentrations and it was found that the values obtained were systematically overpredicted by the delivery system algorithm. New pharmacokinetic microconstants were derived from our data which reflected more accurately the elimination and distribution of propofol in a prospective study involving another 10 children.

Adult↗
PubMed1990

Regulation of hepatic synthesis and secretion of cholesterol and glycerolipids in animals maintained in different nutritional states.

The distribution of newly synthesized and exogenous fatty acids and of newly synthesized cholesterol between cellular and very-low-density lipoprotein (VLDL) lipids was studied in hepatocytes derived from animals fed on a normal diet or on diets supplemented with polyunsaturated fat or sucrose. Phospholipid synthesis from either exogenous or endogenous (biosynthetic) fatty acids was unaffected by nutritional state. Cholesterol synthesis was decreased in the fat-fed animals, but sucrose feeding had no significant effect. In all nutritional states, newly synthesized rather than exogenous fatty acids were better substrates for phospholipid synthesis. In all groups, compared with newly synthesized triacylglycerol, smaller proportions of newly synthesized phospholipid and cholesterol were secreted as VLDLs. This was confirmed in intact animals by using Triton WR-1339. Newly synthesized phospholipid formed a greater proportion of the VLDL glycerolipid in the fat-fed than in the normal or sucrose-fed animals. In all groups, phospholipids labelled from endogenous fatty acids were secreted in preference to those labelled from exogenous fatty acids.

Animals↗
PubMed1988

The human X-linked steroid sulfatase gene and a Y-encoded pseudogene: evidence for an inversion of the Y chromosome during primate evolution.

The mammalian X and Y chromosomes are thought to have evolved from a common, nearly homologous chromosome pair. Although there is little sequence similarity between the mouse or the human X and Y, there are several regions in which moderate to extensive sequence homologies have been found, including, but not limited to, the so-called pseudoautosomal segment, in which X-Y pairing and recombination take place. The steroid sulfatase gene is in the pseudoautosomal region of the mouse, but not in man. We have cloned and characterized the human STS X-encoded locus and a pseudogene that is present on the long arm of the Y chromosome. Our data in humans and other primates suggest that there has been a pericentric inversion of the Y chromosome during primate evolution that has disrupted the former pseudoautosomal arrangement of these genes. These results provide additional insight into the evolution of the sex chromosomes and into the nature of this interesting portion of the human genome.

Animals↗
PubMed1987

Cloning and expression of steroid sulfatase cDNA and the frequent occurrence of deletions in STS deficiency: implications for X-Y interchange.

Human STS is a microsomal enzyme important in steroid metabolism. The gene encoding STS is pseudoautosomal in the mouse but not in humans, and escapes X inactivation in both species. We have prepared monoclonal and polyclonal antibodies to the protein which has been purified and from which partial amino acid sequence data have been obtained. cDNA clones containing the entire coding sequence were isolated, sequenced, and expressed in heterologous cells. Variable length transcripts have been shown to be present and due to usage of alternative poly(A) addition sites. The functional gene maps to Xp22.3-Xpter and there is a pseudogene on Yq suggesting a recent pericentric inversion. Absence of STS enzymatic activity occurs frequently in human populations and produces a visible phenotype of scaly skin or ichthyosis. Ten patients with inherited STS deficiency were studied and eight had complete gene deletions. The possibility that STS deficiency results from aberrant X-Y interchange is discussed.

Amino Acid Sequence↗
PubMed1987

Study of e+

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Journal Article↗
PubMed1985

Transbronchial lung biopsy in pediatric and adolescent patients.

Since data are unavailable on the role of transbronchial lung biopsy (TBB) in pediatric and adolescent patients, we reviewed our two-year experience in 12 patients (median age, 14.5 years). In all 12, the indication for TBB was a persistently abnormal chest roentgenogram (nine with multilobar infiltrates, two with unilateral infiltrates, and one with a cavitary lesion). Overall, a specific diagnosis was made by TBB in six patients, including three patients with sarcoidosis, one with lymphoma, and two with eosinophilic granuloma. In three additional patients, nonspecific histologic findings on TBB combined with clinical findings, roentgenographic patterns, and supplemental laboratory data helped support a diagnosis. Although the need for general anesthesia and the small size of the biopsy specimens may limit the usefulness of TBB in most pediatric patients, TBB may be a useful alternative in carefully selected patients.

Adolescent↗