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Biomedical subjects

A Bhattacharya

Publications and source records attributed to A Bhattacharya.

At least 253 records · Page 14Linked to original sources
PubMed1974

Induction of N-acetylglucosamine kinase in yeast.

The presence of N-acetylglucosamine is essential for the induced synthesis of N-acetylglucosamine kinase in Candida albicans. The enzyme synthesis stops and its concentration in the cells declines rapidly as soon as N-acetylglucosamine is removed from the medium. Experiments with RNA- and protein-synthesis inhibitors indicate that the appearance of new enzyme activity is dependent on concomitant new protein synthesis and the inducer operates at a transcriptional level.

Candida albicans↗
PubMedDate not supplied

Acute intermittent porphyria: pathophysiology and treatment.

Acute intermittent porphyria is caused by an inherent error of porphyrin metabolism characterized by a deficiency of porphobilinogen deaminase and increased activity of delta-aminolevulinic acid synthase, key enzymes necessary for the biosynthesis of heme. During an attack patients may have abdominal pain, vomiting, muscle weakness, constipation and neuropsychiatric symptoms. In the majority of individuals the disease remains clinically latent throughout life. Various drugs and chemicals, hormones and nutritional factors predispose to clinical attacks, probably by inducing hepatic delta-aminolevulinic acid synthase. Avoidance of these substances is important in preventing attacks. Screening of family members to detect genetic carriers permits precautionary measures. Management of attacks includes symptomatic therapy, high carbohydrate intake and intravenous administration of hematin.

Acute Disease↗
PubMedDate not supplied

Neonatal candidemia.

Fifty five clinically diagnosed cases of neonatal septicaemia of the nursery ward, Medical College Hospital Calcutta were subjected to blood culture on two consecutive days in all cases. Bacterial isolates were found in 34 (61.8%) cases as pure growth and candida species from 9 (16.4%) as pure culture. Remaining 12 samples did not yield any growth. Species distribution of candida showed C. albicans 6, C. parapsilosis 2, and C. guillermondii 1. Asphyxia neonatorum was the common feature in all cases of candidaemia. All neonates with candidal infection were low-birth-weight and premature. C. albicans, the predominant species (66.6%) recovered, was responsible for a localised outbreak of infection in the nursery.

Candidiasis↗
PubMedDate not supplied

Use of a computerized postural sway measurement system for neurobehavioral toxicology.

The study of standing posture has been associated with nervous system functioning for over a hundred years. Measures of human standing ability have attracted some attention as indicators of neurotoxic insult. The use of postural sway measures as subclinical indicators of toxicity has not been regularly incorporated into most neurobehavioral test batteries, but the development of microcomputer-controlled systems offers new possibilities. The mechanisms involved in controlling postural sway are discussed, as well as the various measurement techniques. In addition, studies involving the effects of some neurotoxic agents are cited. A postural sway measurement system that is noninvasive, has 1-2-minute test periods, provides immediate test results, and is relatively free of practice and motivation effects is described. Results present the normative characteristics of the sway parameters, a comparison of three data transformation techniques, and the effects of height and weight on the sway parameters. Power calculations were also performed to estimate the number of subjects needed to detect effects at both the 80% and 90% power levels.

Adolescent↗
PubMedDate not supplied

A case of reversible paraparesis following celiac plexus block.

BACKGROUND AND OBJECTIVES: Permanent and acute reversible paraplegia following celiac plexus block (CPB) have been reported. We report a case of prolonged reversible paraparesis after alcohol celiac plexus block. CASE REPORT: A 72-year-old man with primary multicentric pancreatic tumor and multiple hepatic metastases underwent alcohol celiac plexus neurolysis for severe abdominal pain radiating to the back. The patient had complete pain relief after the block but developed paresthesia of the left leg, which then spread to the right leg. Subsequently, loss of flexion and extension of the muscles supplying the left hip, knee, and foot developed. Deep tendon reflexes were brisk on the left compared to the right, and both plantar reflexes gave flexor responses. Magnetic resonance imaging and myelography were normal. Motor-evoked potential recordings showed a spinal cord lesion with involvement of the pyramidal and spinothalamic tracts. Somatosensory-evoked potentials indicated a relative sparing of dorsal column pathways. Physiotherapy was started, the sensory changes gradually subsided, and the patient was discharged 30 days after the block with clinically insignificant neurological deficit. CONCLUSIONS: Paraparesis following alcohol celiac plexus block may be reversible over an extended period of time.

Aged↗
PubMedDate not supplied

Effect of different terpene-containing essential oils on percutaneous absorption of trazodone hydrochloride through mouse epidermis.

The aim of our study was to investigate the enhancing effect of several essential oils in the percutaneous absorption of trazodone hydrochloride (TZN). For this purpose, fennel oil, eucalyptus oil, citronella oil, and mentha oil were applied on the skin membrane in three different ways: included in the transdermal device, as a pretreatment, or both. To investigate the effect of penetration enhancers used in this study on the percutaneous absorption of TZN through mouse epidermis, Keshary-Chien diffusion cells were employed. The receptor phase was constantly stirring saline phosphate buffer of pH 7.4 at 37 +/- 1 degrees C. Results showed that pretreatment of skin with essential oils increases the flux values of TZN compared with the values obtained when the same essential oils were included in the transdermal devices. The percutaneous penetration flux for TZN was increased with skin pretreatment by 10% essential oils in the following order: fennel oil > eucalyptus oil > citronella oil > mentha oil. The amount of TZN retained in the skin after pretreatment with essential oils was found to be very similar in all cases and much higher than in the experiments without skin pretreatment.

Administration, Cutaneous↗
PubMedDate not supplied

Evaluation of workers' perceived sense of slip and effect of prior knowledge of slipperiness during task performance on slippery surfaces.

Forty healthy industrial workers (age: 41.0+/-14.9 years) were tested for postural stability for three simulated tasks: (1) standing upright; (2) rapid trunk movement; and (3) lateral reach during lifting. These tasks were performed on four levels of slippery surfaces under different environmental lighting with new or workers' own old shoes. Prior to postural stability tests, each subject was given the opportunity to assess the surface slipperiness that he or she would encounter in the subsequent postural stability tests. A perceived sense of slip (PSOS) scale was administrated immediately after each test to determine subjects' PSOS. Subjects' postural sway and instability during task performance was determined by using a strain gauge type force platform. Results from this study indicate that subjects who were cautious in assessing surface slipperiness had less postural instability during task performance. Subjects could perceive the likely slips due to the change in task (p=0.0001) and surface slipperiness (p=0.0001). The PSOS scale is reproducible, easy to use, and provides a simple way to evaluate potential slip hazards in the workplace. Results from this study should aid understanding of the factors critical to maintaining postural stability on slippery surfaces, and will help to develop guidelines for safety training and identify slip hazards in the workplace.

Accidents, Occupational↗
PubMedDate not supplied

Exertion and body discomfort perceived symptoms associated with carpentry tasks: an on-site evaluation.

The purpose of this study was to determine how carpenters subjectively perceived the exertion level and body discomfort associated with their daily tasks. Two psychophysical instruments were utilized. The Borg Whole Body Physical Exertion Instrument, a measure of overall physical demand, and the Body Segment instrument (modified Bishop-Corlett Scale), a measure of body discomfort, were given to 73 carpenters at the end of a shift. Carpentry specialties evaluated included ceiling, drywall, formwork, finishing work, pile driving, fixtures, welding, and scaffolding. The mean Borg's exertion score for the subjects combining all specialties was 14.4 (+/-2.51 standard deviation), a score between "somewhat hard" and "hard." The perception of whole body physical exertion appeared to be a consequence of the specific task. There was no significant correlation between whole body physical exertion perception and age or the number of years as a carpenter. The findings from the body discomfort scale for the total group indicated that the three primary discomfort frequencies by body segment were mid-to-lower back (65.8%), knees (45.2%), and the neck (28.8%). The next highest discomfort rating by body segment (back, knee, right wrist, right leg/foot, and right shoulder) for those subjects in the top three job specialties represented (drywall, ceiling, and formwork; n = 38) resulted in significantly higher ratings for back (60.5%) than right leg/foot (34.2%) and right shoulder (31.6%). All other body segment ratings were not significantly different from one another using Tukey's studentized range test.

Adult↗
PubMedDate not supplied

Circular DNA of Entamoeba histolytica encodes ribosomal RNA.

The presence of repeated DNA sequences encoding RNA in Entamoeba histolytica has been reported. In the present study we demonstrate by agarose gel electrophoresis. DNase digestion and electron microscopic analysis that these genes are located on extrachromosomal circular DNA molecules with an approximate size of 26 kb. Detection of replication intermediates suggests the episomal nature of these molecules. Amplified, extrachromosomal rRNA genes appear to be a common feature among the lower eukaryotes, occurring more commonly as linear molecules and less commonly as circles. Entamoeba histolytica is 1 of the few organisms studied in which rRNA genes are located predominantly on extrachromosomal circles.

Animals↗
PubMedDate not supplied

Leishmania donovani: a chemically defined medium suitable for cultivation and cloning of promastigotes and transformation of amastigotes to to promastigotes.

A chemically defined medium using commercially available alpha-MEM supplemented with hemin, HEPES, L-glutamine, D-glucose, folic acid, D-biotin and adenine supports the luxuriant growth and propagation of Leishmania donovani promastigotes. A peak parasite population of about 7.0 x 10(7)/ml at stationary phase and a population doubling time of 11.4 h for high-subpassage promastigotes were obtained. The medium was suitable for transformation of isolated amastigotes from infected hamster spleen. Promastigotes could be detected by culturing kala-azar patients' bone-marrow aspirate or spleen puncture material in this medium. Four out of six freshly transformed isolates gradually adapted and grew well in this medium. Macroscopic colonies appeared on agar plates prepared with the medium within 16-20 days after inoculation. The cloning efficiency was increased about five-fold by glycerol supplementation.

Animals↗
PubMedDate not supplied

Lipophosphoglycan is present in distinctly different form in different Entamoeba histolytica strains and absent in Entamoeba moshkovskii and Entamoeba invadens.

Lipophosphoglycan has recently been demonstrated on the cell surface of Entamoeba histolytica strain HM-1:IMSS. A monoclonal antibody against this molecule had failed to react with some other strains of E. histolytica, including the strain Rahman. To determine if a structurally distinct lipophosphoglycan existed in Rahman, [3H]galactose-labeled glycoconjugates were electrophoresed through sodium dodecyl sulfate polyacrylamide gel electrophoresis. The electrophoretic pattern in Rahman was very different compared to that obtained with strains HM-1:IMSS and 200:NIH. A number of experiments including sensitivity to mild acid, nitrous acid and phosphoinositol-specific phospholipase C suggest that the Rahman glycoconjugate is indeed a lipophosphoglycan-like molecule but distinctly different from that of HM-1:IMSS. Mild acid-treated glycoconjugates from Rahman and HM-1:IMSS revealed the presence of neutral trisaccharides and monosaccharides in Rahman but not in HM-1:IMSS. Human immune sera from amoebiasis patients and a polyclonal antibody against HM-1:IMSS lipophosphoglycan both recognized Rahman glycoconjugate. Thus, while lipophosphoglycan molecules from the two strains share common epitopes, they are clearly distinct from each other. Molecules bearing resemblance to lipophosphoglycan could not be detected in other Entamoeba species, namely Entamoeba invadens and Entamoeba moshkovskii.

Animals↗
PubMedDate not supplied

Molecular changes in Entamoeba histolytica in response to bacteria.

Entamoeba histolytica, the protozoan parasite, is the causative agent of amoebiasis. The degree of virulence, as inferred from invasiveness, of potentially pathogenic strains may be regulated by both host and parasite factors that determine the gut environment. One such factor that plays an important role is the bacterial flora in the gut. Previous studies have clearly shown that bacterial flora is an important determinant of virulence in E. histolytica. However, the exact nature of changes induced in E. histolytica in response to bacteria and their role in virulence is not clear. In this study the levels of a number of molecules potentially important in virulence mechanisms were determined in E. histolytica cells grown with and without normal human bacterial flora, using enzyme-linked immunosorbent assay. Significant changes were observed only after the E. histolytica cells had been adapted to grow with bacterial flora for a number of generations, and not in short term culture.

Animals↗