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S Nicholas

Publications and source records attributed to S Nicholas.

25 records · Page 2Linked to original sources
PubMed1993

Increased Na/H antiport activity and abundance in uremic red blood cells.

Alterations in red blood cell sodium (Na) transport have been described in chronic renal failure. This study examines the possible impact of uremia on two ouabain-insensitive pathways, the Na/H antiporter and the Cl-/NaCO3- anion exchanger. The Vmax of Na/H antiporter measured as Na influx driven by outward H gradient in acid loaded red blood cells was significantly higher in uremic red blood cells versus controls (60.5 +/- 16.5 vs. 24.5 +/- 5.4 mmol/liter cells/hr, P < 0.025). This increase in activity was associated with an increased abundance of the Na/H antiporter as determined by immunologic analysis using an affinity purified polyclonal antibody to the human NHE-1 isoform of the antiporter. By contrast, the activity of the anion exchanger measured as the DIDS-sensitive lithium (Li) influx was similar in uremic versus control red blood cells (2.10 +/- 0.18 vs. 2.14 +/- 0.20 mmol/liter cells/hr). These experiments, when considered in conjunction with prior studies showing normal Na/Li countertransport in uremia indicate that there is a selective increase in the number of functional Na/H antiporters in uremic red blood cells and that Na/Li countertransport measurements may not be a valid marker for Na/H antiporter activity in red blood cells in patients requiring dialysis for end-stage renal failure.

Aged↗
PubMed1991

Cryptosporidiosis in the Isle of Thanet; an outbreak associated with local drinking water.

An outbreak of cryptosporidiosis occurred in the Isle of Thanet during December 1990 and January 1991. A total of 47 cases ranging in age from 2 months to 85 years were identified in residents from the Margate, Broadstairs and Ramsgate areas, with dates of onset of illness from 3 December to 14 January. A case-control study demonstrated a strong statistical association between illness and the consumption of unboiled tap water from a particular source, with evidence of a dose-response relationship. Although no cryptosporidial oocysts were identified in samples of untreated or treated water taken during the investigation, the results were consistent with the view that the source of infection was treated river water which was used to supplement borehole water.

Adolescent↗
PubMed1988

Live virus vaccines in human immunodeficiency virus-infected children: a retrospective survey.

Live virus vaccines can cause serious adverse reactions when administered to immunocompromised patients. Because children infected with human immunodeficiency virus (HIV) may be immunosuppressed, immunization of these children with live virus vaccines is a potential problem. A retrospective survey was conducted by the New York City Department of Health, with consultation from the Centers for Disease Control, to evaluate the frequency of serious adverse events following receipt of live vaccines among children with HIV infection receiving pediatric care in New York City and New Jersey. Outpatient records of 319 children being cared for by 16 participating physicians were reviewed. Of the 319 charts, 221 (69%) contained vaccination histories. Perinatal transmission of HIV infection was suspected for 208 (94%) of the 221 cases and infection via transfusion for the remaining 13 (6%). Of the 221 for whom immunization histories were available, 180 (81%) had received at least one dose of live oral polio vaccine and 70 (32%) had received measles, mumps, and rubella vaccine. There were 120 children for whom a temporal relationship between immunization and onset of symptoms of immunodeficiency could be seen; 46/120 had received at least one dose of oral polio vaccine and 23/45 had received measles, mumps, and rubella vaccine after onset of symptoms. Although follow-up of this population has been limited, there were no reports of serious adverse events such as typical or atypical measles, paralytic poliomyelitis, or aseptic meningitis in the month following vaccination.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1985

Ultrastructure of the anterior buccal gland of the rat.

The anterior buccal gland of the rat is a mucous salivary gland which develops as a branch of the main (Stensen's) duct of the serous parotid gland, a few mm from its oral orifice. The purpose of the present study was to further characterize the mature gland by means of electron microscopy and the histochemical demonstration of myoepithelial cells. The tubuloacini were found to have intercellular extensions (canaliculi) of the lumina, prominent Golgi complexes, and mucous secretory granules with a biphasic substructure. Discharge was by exocytosis of individual granules. The tubuloacini joined directly to striated ducts; no intercalated ducts were seen. First-order excretory ducts had larger lumina and shorter columnar cells, with fewer mitochondria and basal infoldings, than the striated ducts. Myoepithelial cells invested the tubuloacini but not the ducts. The anterior buccal gland has several features that are unusual for a minor salivary gland of mucous type, and which are usually associated with serous glands such as the parotid. It should provide a particularly interesting model for investigating factors which control the differentiation of secretory and myoepithelial cells, and the glycosylation of polypeptides to form mucous secretory products.

Alcian Blue↗