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Biomedical subjects

C Young

Publications and source records attributed to C Young.

At least 181 records · Page 10Linked to original sources
PubMed1993

Purification and properties of Alligator mississipiensis cytochrome c.

Cytochrome c has been purified to homogeneity from alligator liver (Alligator mississipiensis) using aluminum sulfate precipitation, CM-cellulose and gel-filtration chromatography, and reverse-phase HPLC. The protein exhibited a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an approximate molecular weight of 12,000 Da. Oxidized and reduced visible spectra yielded maxima at 408 (tau) nm and 315 (delta), 415 (tau), 520 (beta), and 550 (alpha) nm, respectively, while potentiometric titrations in the presence of dye-mediators yielded an Eo of +265 mV. N-terminal analysis of the protein yielded no sequence which indicates a blocked residue. A combination of amino acid sequencing, using peptides obtained from Staphylococcus aureus V8 protease, endoproteinase Lys-C, and CNBr digests of the protein and total amino acid analyses, using equine and avian cytochromes c as standards yielded the primary sequence GDVEKGKKIFVQKCAQCHTVEKGGKHKTGPNLHGLIGRKTGQAPGFSYTEANKNKGITWGEETLMEYLE NPKKYIPGTKMIFAGIKKKPERADLIAYLKEATSN. Comparison with sequences of other cytochromes c indicated the closest similarity to cytochrome c from snapping turtle (Chelydra serpentina) with substitutions at five positions corresponding to residues 32 (His-->Asn), 44 (Glu-->Pro), 89 (Ala-->Pro), 100 (Asp-->Glu), and 104 (Lys-->Asn), respectively. The presence of Pro and Asn residues at positions 89 and 104, respectively, are unique to alligator cytochrome c.

Alligators and Crocodiles↗
PubMed1993

Small intestinal mucosa changes, including epithelial cell proliferative activity, of children receiving total parenteral nutrition (TPN).

We examined the small intestinal histology disaccharidase activities as well as the incorporation of [3H]thymidine into DNA of biopsies maintained in organ culture from seven children (ages 9 months to 5 years) receiving total parenteral nutrition (TPN). Three children suffered from inflammatory bowel disease and received TPN for one month (short term). Four required long-term TPN (> 9 months) for short-bowel syndrome. DNA was extracted from the samples following serial precipitation with perchloric acid. Results were compared to those from 22 age-matched children investigated for abdominal pain or chronic diarrhea. Short-term TPN resulted in slightly lower lactase, sucrase, and palatinase activities that were not statistically different from controls. Long-term TPN resulted in focal mild villus atrophy and a decrease in disaccharidase activity in two patients. Biopsies from long-term TPN patients incorporated less thymidine compared to those of controls (P < 0.001) when data was expressed per total biopsy (3.6 +/- 1.1 vs. 8.4 +/- 1.1 fmol) or per milligram of tissue (1.0 +/- 0.12 vs 2.7 +/- 0.7 fmol). The above data are in general agreement with the hypoplastic effect of TPN in animals. However, in children, much longer periods of TPN are required to realize the changes.

Adolescent↗
PubMed1993

Perinatal food restriction in rats reduces the content but not concentration of liver extracellular matrix proteins.

Fibrosis of the liver has been reported to be associated with malnutrition, based on qualitative histological and histochemical approaches. The aim of this study was to quantitatively examine the effect of perinatal food-restriction on the expression of extracellular matrix components of the liver, using rats fed 50% of ad libitum intake, determined by the food consumption of the control group on the previous day. Levels of extracellular matrix proteins were measured by dot blot analysis using monospecific antibodies against collagen types I, III and IV, laminin and fibronectin. The body weights of 4, 8 and 13-wk-old malnourished groups were 25, 35 and 48% of the control group body weights, respectively, and the liver weights were 22, 32 and 60% of the controls. The total contents of the extracellular matrix components were significantly reduced to 30, 34 and 58% of the controls, but when expressed per tissue or per milligram protein there were no significant differences. Indirect immunofluorescence revealed no major changes in extracellular matrix localization. The major histological change in the food-restricted rats was fatty infiltration. Our observations suggest that the effect of perinatal food restriction is mainly liver steatosis, and that the liver of food-restricted animals during the perinatal period has the capacity to preserve its main extracellular matrix components.

Animals↗
PubMed1993

Resource utilization in treatment of diabetic ketoacidosis in adults.

This study defines determinants of cost of treatment of diabetic ketoacidosis. A chart review for 92 cases of ketoacidosis from 1988 to 1992 in 40 females and 25 males (age range 18 to 81) showed a length of stay of 5.7 +/- 4.9 d. Length of stay did not correlate with the level of nursing care or any other component of the initial order set. Length of stay was shorter in cases managed by diabetologists. Length of stay was inversely proportional to the interval from arrival to the first shot of intermediate or long-acting insulin. Length of stay was longer in subjects with a positive bacterial culture (mean, 9.1 d) and was longer in subjects who arrived in the evening. There was a female predominance in total and recurrent cases of ketoacidosis. Female patients received fewer educational sessions than males. The grade of acidosis affected the duration of acidemia, but the grade of acidosis, APACHE scores, and admission lab values did not correlate with length of stay. The use of an intensive care unit (ICU) included more testing and expense without uniform clear benefit. Optimal transition from intensive to routine management includes resumption of long-acting insulins as soon as possible. Optimization of hospital care and reduction of incidence of ketoacidosis in females would have a marked effect on health care costs.

Adolescent↗
PubMed1992

Chylous ascites: total parenteral nutrition as primary therapeutic modality.

A female infant with Down syndrome and congenital chylous ascites presented at birth with respiratory distress secondary to marked abdominal distension. Total parenteral nutrition (TPN) and paracentesis were the primary therapeutic modality. On hyperalimentation, however, ascites initially recurred, requiring additional paracenteses to improve respiratory distress. The chylous ascites, lymphopenia and hypoalbuminemia were relieved after 10 weeks of TPN administration. We recommend a long-term course (10 weeks) of TPN before an exploratory laparatomy and possible surgical intervention are considered.

Chylous Ascites↗
PubMed1992

Pitfalls in comparing immigrants with the Australian-born population with particular reference to socioeconomic status.

"With the increasing interest in the impact of immigration on the character of...Australia's population it is useful to draw attention to the differences that can occur when comparisons of the immigrant and the host population with respect to socioeconomic status are based on aggregate rather than on disaggregate measures. In this paper the discussion focuses on the implications of not disaggregating by age and sex, with respect to such variables as: post-school qualifications, occupation, and labour-force participation, using the total overseas-born population in Australia as an example. The analysis demonstrates the fact that the different age structures of the immigrant and the host populations can result in deficiencies in the aggregate rates."

Age Distribution↗
PubMed1992

Time course of permeability changes and PMN flux in rat trachea following O3 exposure.

Changes in rat tracheal epithelial permeability and polymorphonuclear leukocyte (PMN) populations during a 24-hr time period following a 3-hr exposure to 0.8 ppm ozone (O3) were investigated. An increase in permeability to 99mTc-diethylene-triaminepentaacetate (DTPA) occurred immediately after the exposure, peaked at the 8-hr time point and decreased to control level by 24 hr. For correlation with tracheal permeability, tracheal cross sections were stained with naphthol AS-D chloroacetate and PMNs were scored by their location as well as staining characteristics (positive or negative). The total PMN population remained at the control value at the 0-, 4-, and 8-hr time points, and increased at 12 hr, followed by a rapid decline to below the control value for the remaining time points. There was a shift at the 8-hr time point in the population location, from the vasculature to the interstitium, which returned to control values at 12 hr. The percentage stained PMNs increased significantly at 16 hr while remaining at control values for all other time points. The data reveal that there is a significant increase in tracheal epithelial permeability immediately after the exposure, but the overall increase in the PMN population is preceded by a lag phase. A decrease in the vascular pool of PMNs concomitant with an increase in the interstitial pool of PMNs suggests their migration from blood to the interstitium after ozone exposure. These data indicate that while PMNs may play a role in permeability changes of tracheal epithelium, the initiation is most likely due to other factors.

Animals↗
PubMed1992

Different distributions of dystrophin and related proteins at nerve-muscle junctions.

The distributions of dystrophin, 'dystrophin-related protein' (DRP) and beta-spectrin were compared with that of acetylcholine receptors (AChRs) at rat nerve-muscle junctions (NMJs) using immunofluorescence techniques. In sections, monoclonal antibodies (MAbs) to dystrophin and beta-spectrin labelled the entire sarcolemma but were concentrated at the NMJs while those to DRP labelled only NMJs. In permeabilized muscle fibres, DRP was precisely co-localized with the AChRs, whereas the zone of high density labelling of dystrophin and beta-spectrin extended 0.3-0.4 microns beyond the AChRs. Within the NMJ, the labelling of DRP appeared as a series of interconnecting lines similar to that of AChRs. However, labelling of dystrophin and beta-spectrin was consistently more punctate. These data suggest DRP is more closely associated with AChRs than are dystrophin or beta-spectrin.

Animals↗
PubMed1992

Linguistic performance as a function of abstract task demands in children with spina bifida.

Children with spina bifida and hydrocephalus (SBH) have been observed to have deficits in discourse, characterized by a high frequency of irrelevant utterances and poorer performance with abstract than concrete language. The Preschool Language Assessment Instrument (PLAI) was used to compare children with SBH and language-age controls on discourse skills at four levels of abstraction. In addition, a qualitative assessment of differences in types of inadequate productions was conducted. Children with SBH performed comparably to controls on concrete levels of the PLAI, but they produced significantly more 'no response' and irrelevant responses than the controls.

Attention↗
PubMed1992

A porcine model for adipose tissue-derived endothelial cell transplantation.

The transplantation of endothelial cells represents a technology which has been suggested for applications ranging from improvement in function of implanted vascular devices to genetic therapy. The use of microvascular endothelial cell transplantation has seen increased use both in animal studies as well as clinical use. This report describes our techniques for the isolation and establishment of initial cultures of microvascular endothelial cells derived from porcine fat. A variety of anatomic sites within the pig were evaluated to determine the appropriateness of different sources of fat for endothelial cell isolation. The properitoneal fat was determined to be optimal due to the predominance of endothelium in this tissue and the ease of isolation of microvascular endothelium following collagenase digestion. The study of endothelial cell transplantation in the porcine model is now possible using the methods described for adipose tissue-derived microvessel endothelial cell isolation.

Actins↗
PubMed1992

In vitro postantibiotic effect of roxithromycin and erythromycin against gram-positive cocci.

A persistent suppression of bacterial growth following a brief exposure to an antibiotic (postantibiotic effect [PAE]) has been described for a variety of antibiotics and microorganisms. Data concerning PAE have not yet been demonstrated in Taiwan. In this study, the PAEs of erythromycin (EM) and roxithromycin (RXM) against 4 strains of Staphylococcus aureus, 3 of Streptococcus pyogenes and 1 of Streptococcus pneumoniae were tested. Dilution method was used for removal of drugs. Two controls, one free of drug and one in 1/1000 of the original drug concentrations were used. The results showed that the PAE lasted longer in strains of S. aureus (RXM 1.7-2.1 h; EM 1.7-2.1 h) and S. pyogenes (RXM 1.7-3.0 h; EM 1.9-2.9 h) than those in S. pneumoniae (RXM 0.6-1.6 h; EM 0.8-1.4 h). There was no difference of PAE between RXM and EM against each bacterial strain tested.

Erythromycin↗
PubMed1992

Structure and function of neuromuscular junctions in the vastus lateralis of man. A motor point biopsy study of two groups of patients.

The properties of neuromuscular junctions (NMJs) in the vastus lateralis of man have been studied in motor point biopsy samples and compared with those reported for lower vertebrates (frogs and mice). The patients studied had no convincing evidence of a primary disturbance of neuromuscular transmission or other neurogenic component. Morphological studies were made using a variety of methods at the light- and electron-microscope levels. The size of the presynaptic nerve terminal and the area of postsynaptic specialization were smaller, relative to the size of the muscle fibres, than in the lower vertebrates. In contrast, the extent of postsynaptic folding was greater. Intracellular recordings from single muscle fibres showed that the duration of synaptic currents was longer than in most other vertebrates so far studied and that the number of transmitter 'quanta' released by a single nerve impulse, about 20, was lower, probably reflecting the small size of the presynaptic terminals. The hypothesis is discussed that in man, a relatively weak effect of transmitter on the muscle fibre surface is amplified by voltage-dependent sodium channels which have been shown in the rat to be concentrated in the depths of the synaptic folds. The implications of this hypothesis for the interpretation of pathological findings in myasthenic syndromes are also discussed.

Adolescent↗
PubMed1992

Infantile osteopetrosis: report of two cases.

Two cases of infantile osteopetrosis are reported. Both were males aged four and eight months at presentation. They presented with osteosclerotic change of the bone, leukoerythroblastic anemia, optic atrophy, hepatosplenomegaly and frequent infection. The histology of the bone showed thickened bone trabeculae with little osteoclastic activity, although in one patient the number of osteoclasts increased, while in the other they did not. One received a bone marrow transplant (BMT) but died from disseminated cytomegaloviral infection, pulmonary hemorrhage and sepsis. The post-transplant marrow histology showed evidence of engraftment and osteoclastic activity. The other only received a course of prednisolone, which was of little help. His condition has followed a natural course with progressive visual impairment and marrow failure. Our cases suggest that infantile osteopetrosis should be taken into consideration in dealing with infants who present with early marrow failure and that patients of infantile osteopetrosis should receive BMT. BMTs appear to be the only cure. They should be given as early as possible to avoid major consequences and severe infection.

Bone Marrow Transplantation↗