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Biomedical subjects

J P Rao

Publications and source records attributed to J P Rao.

At least 19 recordsLinked to original sources
PubMed2006

Oligodendroglial tumor chemotherapy using "decreased-dose-intensity" PCV: a Singapore experience.

The authors propose "decreased-dose-intensity" PCV (procarbazine, lomustine [CCNU], and vincristine) chemotherapy for Asian patients with oligodendroglial tumors. In this study, all seven patients with oligodendroglioma (OD) and eight with anaplastic oligodendroglioma (AO) had objective responses or stable disease. Median progression-free survival was greater than 29 months (OD) and 36.5 months or greater (AO); 86% of patients with OD and 63% with AO remain progression-free. Twenty-four Common Toxicity Criteria Grade 3/4 adverse events were noted.

Adult↗
PubMed2001

Expression of Chlamydia trachomatis genes encoding products required for DNA synthesis and cell division during active versus persistent infection.

During persistent infection, the intracellular bacterial pathogen Chlamydia trachomatis is viable but severely attenuates the production of new, infectious elementary bodies (EBs). To investigate the reasons for this lack of new EB output, we analysed the expression of chlamydial genes encoding products required for DNA replication and cell division, using in vitro models of active versus persistent infection and synovial tissue samples from patients with chronic Chlamydia-associated arthritis. Hep-2 cells were infected with K serovar C. trachomatis and harvested at t = 0-48 h post-infection (p.i; active). Human monocytes were infected similarly and harvested at t = 1-7 days p.i. (persistent). RNA preparations from infected/uninfected cells and patient samples were subjected to reverse transcription-polymerase chain reaction (RT-PCR) targeting polA, dnaA, mutS and parB mRNA, related to chlamydial DNA replication/segregation; these were expressed in infected Hep-2 cells from 11 to 48 h p.i; ftsK and ftsW, related to cell division, were expressed similarly. Real-time PCR analyses demonstrated that significant accumulation of chlamydial chromosome began at about 12 h p.i. in infected Hep-2 cells. In infected human monocytes, polA, dnaA, mutS and parB mRNA were produced from days 1-7 p.i. and were weakly expressed in patient samples. Real-time PCR indicated the continuing accumulation of chlamydial chromosome during the 7 day monocyte infection, although the rate of such accumulation was lower than that occurring during active growth. However, transcripts from ftsK and ftsW were detected only at 1 day p.i. in infected monocytes but not thereafter, and they were absent in all patient samples. Thus, genes whose products are required for chlamydial DNA replication are expressed during persistence, but transcription of genes whose products are required for cytokinesis is severely downregulated. These data explain, at least in part, the observed attenuation of new EB production during chlamydial persistence.

Bacterial Proteins↗
PubMed2001

Chlamydia pneumoniae expresses genes required for DNA replication but not cytokinesis during persistent infection of HEp-2 cells.

Chlamydia pneumoniae causes community-acquired pneumonia and is associated with several chronic diseases, including asthma and atherosclerosis. The intracellular growth rate of C. pneumoniae slows dramatically during chronic infection, and such persistence leads to attenuated production of new elementary bodies, appearance of morphologically aberrant reticulate bodies, and altered expression of several chlamydial genes. We used an in vitro system to further characterize persistent C. pneumoniae infection, employing both ultrastructural and transcriptional activity measurements. HEp-2 cells were infected with C. pneumoniae (TW-183) at a multiplicity of infection of 3:1, and at 2 h postinfection gamma interferon (IFN-gamma) was added to the medium at 0.15 or 0.50 ng/ml. Treated and untreated cultures were harvested at several times postinfection. RNA was isolated and reverse transcribed, and reverse transcription (RT)-PCR analyses targeting primary transcripts from chlamydial rRNA operons as well as dnaA, polA, mutS, minD, ftsK, and ftsW mRNA were done. Some cultures were fixed and stained for electron microscopic analysis, and a real-time PCR assay was used to assess relative chlamydial chromosome accumulation under each culture condition. The latter assays showed that bacterial chromosome copies accumulated severalfold during IFN-gamma treatment of infected HEp-2 cells, although less accumulation was observed in cells treated with the higher dose. Electron microscopy demonstrated that high-dose IFN-gamma treatment elicited aberrant forms of the bacterium. RT-PCR showed that chlamydial primary rRNA transcripts were present in all IFN-gamma-treated and untreated cell cultures, indicating bacterial metabolic activity. Transcripts from dnaA, polA, mutS, and minD, all of which encode products for bacterial chromosome replication and partition, were expressed in IFN-gamma-treated and untreated cells. In contrast, ftsK and ftsW, encoding products for bacterial cell division, were expressed in untreated cells, but expression was attenuated in cells treated with low-dose IFN-gamma and absent in cells given the high dose of cytokine. Thus, the development of persistence included production of transcripts for DNA replication-related, but not cell division-related, genes. These results provide new insight regarding molecular activities that accompany persistence of C. pneumoniae, as well as suggesting requirements for reactivation from persistent to productive growth.

Bacterial Proteins↗
PubMed2000

Calmodulin mediated activation of acetyl-CoA carboxylase during aflatoxin production by Aspergillus parasiticus.

The relevance of Ca2+-calmodulin-mediated processes in channelling acetate for aflatoxin formation was investigated by studying the influence of trifluoperazine (an anticalmodulin agent) on [14C]-acetate incorporation and activity of acetyl-CoA carboxylase in Aspergillus parasiticus NRRL 2999. Culturing the organism in presence of 0.14 mmol l-1 trifluoperazine resulted in 55% decrease of [14C]-acetate incorporation into aflatoxin B1, along with an 80% decrease in acetyl-CoA carboxylase activity at periods corresponding to maximal aflatoxin production. Concomitant decrement (35%) in the activity of glucose-6-phosphate dehydrogenase indicated decreased availability of reduction potential (NADPH) required for aflatoxin biosynthesis. The ability of calmodulin to activate and trifluoperazine to inhibit acetyl-CoA carboxylase activity in a dose-dependent manner was also noted under in vitro conditions. The combined results suggest calmodulin-mediated activation of acetyl-CoA carboxylase as an important event for aflatoxin production.

Acetates↗
PubMed1998

Clinical evaluation of the Alta hip bolt in peritrochanteric hip fractures.

We reviewed the clinical and radiographic results of 58 patients with peritrochanteric fractures treated with the Alta hip bolt (a sliding compression device that inserts a dome plunger in the femoral head instead of a hip screw). This group was compared with a group of 53 patients treated with conventional hip screws. Three patients (5.2%) treated with the Alta hip bolt and three patients (5.7%) treated with conventional hip screw had failure of fixation. Failure of fixation consistently occurred in patients with unstable fracture patterns or significant osteopenia. There were no cases of bolt cut-out in stable intertrochanteric fractures. We conclude that the Alta hip bolt performs as well as sliding hip screws in peritrochanteric fractures, but the additional learning curve and increased cost do not justify its routine use at this point in time.

Aged↗
PubMed1997

Results of arthroscopic versus open Bankart suture repair.

The purpose of this study was to compare patients with anterior shoulder instability who were treated with an open Bankart procedure with those treated with an arthroscopic procedure. During a 3-year period, 43 patients (44 shoulders) were surgically treated. Thirty-four patients were available for followup. Eighteen shoulders had open Bankart procedure, and 16 shoulders were treated arthroscopically. Capsular laxity can be better assessed with the open procedure. A Bankart lesion was found in all the patients in both series. Average followup for Group 1 was 34 months, and for Group 2, it was 23 months. Group 1 had 83% good to excellent results with no recurrent dislocation or reoperation. Group 2 had 50% good to excellent results, and 50% fair to poor results with 3 recurrent dislocations and 4 recurrent subluxations that required second operation. The average loss of external rotation in Group 1 was not significantly greater than that in Group 2. Sixteen patients in Group 1 and 8 patients in Group 2 were able to return to their primary work or sport. Results of arthroscopic Bankart repair do not equal those of the open Bankart procedure for the rate of recurrence and postoperative range of motion. The followup reported is short, and more dislocations can be anticipated with longer followup.

Adolescent↗
PubMed1997

Irreducible superior dislocation of the patella requiring open reduction.

The authors describe a case of superior dislocation of patella that was irreducible by closed methods. Extensive review of the literature revealed that this is the first case reported in which an open reduction was needed to reduce a superior dislocation of the patella to unlock the osteophytes, which were blocking the closed reduction.

Aged↗
PubMed1996

Bacterial lipopolysaccharide induces diarrhoea in caecectomized mice.

Castor oil, lipopolysaccharide of Escherichia coli, and endotoxin of Salmonella typhimurium were used for inducing diarrhoea in sham operated or caecectomized mice. Copious diarrhoea was induced by lipopolysaccharide (LPS) in caecectomized mice. Characteristics of diarrhoea induced by castor oil were not different between the two groups. It is concluded that caecectomized mice may be a good model to study lipopolysaccharide-induced diarrhoea.

Animals↗
PubMed1995

Rhizobium meliloti lacking mosA synthesizes the rhizopine scyllo-inosamine in place of 3-O-methyl-scyllo-inosamine.

The Rhizobium meliloti Rm220-3 mos locus producing the rhizopine scyllo-inosamine (SI) in nodules is shown to consist of three ORFs (ORF1, mosB and mosC) arranged in an operon structure. This differs from the R. meliloti L5-30 mos locus, which produces 3-O-methyl-scyllo-inosamine (3-O-MSI), by the complete absence of mosA. The deletion covers a region of 1235 nt and includes the entire mosA gene as well as the sequence both upstream and downstream. As a result, Rm220-3 mos ORF1 shares a 5' region common with L5-30 ORF1 but includes an additional 10 bp insertion and a section in the L5-30 mosA and mosB intercistronic region. Antibodies against L5-30 Mos proteins detected MosB and MosC proteins in Rm220-3-induced nodules but no translation product for either ORF1 or mosA was detected. A construct prepared from the L5-30 mos locus which has a truncated mosA gene produces SI rather than 3-O-MSI, confirming this gene is involved in a methylation step in the production of 3-O-MSI. Further, changes made to this ORF result in reduced levels of the rhizopine.

Amino Acid Sequence↗
PubMed1994

Does phosphorylation affect transport of inorganic phosphate?

1. This study investigated the effects of fructose and 2-deoxyglucose on the uptake and release of phosphate from everted intestinal sacs of mice. 2. Both the sugars significantly decreased the release of phosphate without affecting the uptake. 3. Succinate and fumarate were able to partially reverse the inhibition of phosphate release exerted by fructose but not that exerted by 2-deoxyglucose. 4. Pre-loading with mannoheptulose, a known inhibitor of hexokinase, improved the release of phosphate in the presence of either of these sugars. 5. Adrenaline, known to inhibit phosphorylation of 2-deoxyglucose, reduced the inhibition exerted by this sugar on phosphate release. 6. These results indicate that the inhibition of phosphate release caused by these sugars may be due to the trapping of free phosphate during their metabolism in the gut wall.

Animals↗
PubMed1993

Role of sodium-potassium ATPase in phosphate transport by the everted sacs of mouse intestine.

1. This study investigated the uptake and release of phosphate from everted intestinal sacs of mice. 2. When the activity of sodium-potassium ATPase was altered (by changing the cationic concentrations in the medium by the addition of ouabain and the manipulation of metabolism by the use of selective inhibitors or stimulants), the release of phosphate appeared to be much more affected by the changes than the uptake of phosphate. 3. A small sodium gradient allowed uptake to be maintained. The addition of ouabain in the presence of an attenuated gradient significantly reduced the uptake and release of phosphate. The inhibitory effect of ouabain on phosphate release was partly reversed by an increase in the potassium concentration in serosal fluid. 4. These results indicate a role for sodium-potassium ATPase in phosphate release from the intestine.

Adenosine↗
PubMed1992

Further analysis of a transcript nested within the actin 5C gene of Drosophila melanogaster.

Previously we uncovered a 0.45-kb transcript within the 3' end transcribed untranslated region (3'UTR) of actin gene at 5C3-4 (act5C) of Drosophila melanogaster. We report here that its sequence bears no similarity to the known DNA or protein sequences. This and act5C transcripts are loaded on different polyribosomal classes. Gel retardation experiments performed with this fragment and several others from act5C reveal no DNA binding activity. The 0.45-kb transcript, initially isolated from different developmental stages of D. melanogaster embryogenesis, is also expressed in Drosophila Kc tissue culture cells, which will be used in transformation experiments designed to identify regulatory features of the nested gene and its possible interaction at some level with its "host" act5C gene.

Actins↗
PubMed1992

Repair of a glenoid fracture using a powered stapler.

Scapular fractures account for only 1% of all fractures, and displaced intra-articular glenoid fractures are very rare. This report describes the operative treatment of a displaced intra-articular fracture of the glenoid in a 33-year-old man. The fracture was repaired by open reduction and internal fixation, using a pneumatically powered stapler for initial stabilization of the fracture fragment and anatomic reduction of the articular surface.

Adult↗