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Biomedical subjects

N Bhalla

Publications and source records attributed to N Bhalla.

6 recordsLinked to original sources
PubMed2001

Genes involved in sister chromatid separation and segregation in the budding yeast Saccharomyces cerevisiae.

Accurate chromosome segregation requires the precise coordination of events during the cell cycle. Replicated sister chromatids are held together while they are properly attached to and aligned by the mitotic spindle at metaphase. At anaphase, the links between sisters must be promptly dissolved to allow the mitotic spindle to rapidly separate them to opposite poles. To isolate genes involved in chromosome behavior during mitosis, we microscopically screened a temperature-sensitive collection of budding yeast mutants that contain a GFP-marked chromosome. Nine LOC (loss of cohesion) complementation groups that do not segregate sister chromatids at anaphase were identified. We cloned the corresponding genes and performed secondary tests to determine their function in chromosome behavior. We determined that three LOC genes, PDS1, ESP1, and YCS4, are required for sister chromatid separation and three other LOC genes, CSE4, IPL1, and SMT3, are required for chromosome segregation. We isolated alleles of two genes involved in splicing, PRP16 and PRP19, which impair alpha-tubulin synthesis thus preventing spindle assembly, as well as an allele of CDC7 that is defective in DNA replication. We also report an initial characterization of phenotypes associated with the SMT3/SUMO gene and the isolation of WSS1, a high-copy smt3 suppressor.

Alleles↗
PubMed1999

The conserved protein kinase Ipl1 regulates microtubule binding to kinetochores in budding yeast.

Chromosome segregation depends on kinetochores, the structures that mediate chromosome attachment to the mitotic spindle. We isolated mutants in IPL1, which encodes a protein kinase, in a screen for budding yeast mutants that have defects in sister chromatid separation and segregation. Cytological tests show that ipl1 mutants can separate sister chromatids but are defective in chromosome segregation. Kinetochores assembled in extracts from ipl1 mutants show altered binding to microtubules. Ipl1p phosphorylates the kinetochore component Ndc10p in vitro and we propose that Ipl1p regulates kinetochore function via Ndc10p phosphorylation. Ipl1p localizes to the mitotic spindle and its levels are regulated during the cell cycle. This pattern of localization and regulation is similar to that of Ipl1p homologs in higher eukaryotes, such as the human aurora2 protein. Because aurora2 has been implicated in oncogenesis, defects in kinetochore function may contribute to genetic instability in human tumors.

Aurora Kinases↗
PubMed1997

A single-step stent delivery, deployment, and expansion system.

Placement of intracoronary stents now comprises a significant number of the percutaneous coronary revascularization procedures being performed in high-volume interventional laboratories in the United States. Stents have become popular because of the reliable acute results, and decreased restenosis. The most common stent currently in use in the United States is the Palmaz-Schatz balloon-expandable stent (PS stent). This stent delivery system (SDS) usually requires predilatation with a balloon and another dilatation, after stent deployment, with a high-pressure balloon in order to adequately expand the stent. We report on a new hybrid stent-delivery system using the PS stent, the sheath from the SDS, and an NC Bandit balloon. This new hybrid system is safe and significantly decreases the procedure time, fluoroscopy time, and need for additional stents due to angiographic dissection resulting from inexact positioning of the high-pressure balloon within the initially deployed stent, and/due to inadequate placement of the first stent. This may be an ideal delivery system for single stent deployment using currently approved FDA equipment.

Angioplasty, Balloon, Coronary↗
PubMed1993

Changing profile of haematogenous osteomyelitis in a teaching hospital.

A total of 155 consecutive patients of osteomyelitis were studied clinically, radiologically and bacteriologically. The follow up ranged from 2 1/2 to 4 1/2 yr (average 3.5 yr). Age varied from 8 months to 50 yr. Onset of the disease was acute in 106 and insidious in 49 patients. Of these 116 cases were treated conservatively which include 12 treated by incision and drainage. The rest underwent surgery (saucerization, curettage, sequestrectomy etc.). There was a trend for osteomyelitis to shift from the known incidence in early age to adulthood, acute to insidious onset and infection by Gram positive to Gram negative organisms.

Adolescent↗
PubMedDate not supplied

Effects of free glycerol contained in intravenous fat emulsion on plasma triglyceride determination.

BACKGROUND: Plasma triglyceride analyses to evaluate the clearance of IV fat emulsion are necessary in patients receiving parenteral nutrition. Enzymatic kits for triglyceride analysis measure the glycerol that is hydrolyzed from triglyceride. This study investigates the effect of fat emulsion free glycerol on plasma triglyceride determination. METHODS: Venous blood from fasting volunteers (n = 10) was drawn into tubes containing EDTA and was centrifuged to separate the plasma. An IV fat emulsion containing 2.25% glycerol was added to plasma samples to create serial dilutions ranging from 0.049% to 0.245% final lipid concentration. Total triglyceride and free glycerol concentrations were determined in each dilution and control sample. The free glycerol concentration was subtracted from the total triglyceride concentration to yield a true triglyceride value. RESULTS: Increasing concentrations of fat emulsion added to donor plasma produced increases in total triglyceride and free glycerol concentrations. The increase in free glycerol concentration produced significant concentration-related differences between total and true triglyceride concentrations. CONCLUSIONS: The total triglyceride level overestimated the true triglyceride concentration due to fat emulsion free glycerol. To assure reliable triglyceride results in patients receiving fat emulsion, blanking for free glycerol should be considered.

Adult↗