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Biomedical subjects

P Sengupta

Publications and source records attributed to P Sengupta.

At least 19 recordsLinked to original sources
PubMed1991

MAT alpha 1 can mediate gene activation by a-mating factor.

In the yeast Saccharomyces cerevisiae, expression of alpha-specific genes is governed by the MAT alpha 1 and MCM1 gene products. MAT alpha 1 and MCM1 bind cooperatively to PQ elements upstream of alpha-specific genes. The PQ element not only directs alpha-specific expression but can also direct gene induction in response to treatment with a-mating pheromone. We have used gene fusions to investigate whether induction conferred by the PQ box is mediated through either MAT alpha 1 or MCM1, or a combination of both. When MCM1 is fused to the DNA-binding domain of the bacterial repressor LexA, this fusion protein is capable of trans-activating a lacZ reporter gene driven by a LexA operator. However, the transcriptional activity of the MCM1-LexA fusion is not further enhanced by treatment of cells with a-factor. A MAT alpha 1-LexA fusion protein is also capable of trans-activation through a LexA operator. Moreover, the activity of the MAT alpha 1-LexA fusion protein can be further induced by treatment with a-factor. When progressive deletions are made from the amino terminus of MAT alpha 1 in the fusion protein, the basal level of trans-activation progressively decreases, but the inducibility of the fusion protein increases. MAT alpha 1-LexA fusion proteins, which have greater than or equal to 57 amino acids deleted from the amino terminus of MAT alpha 1 are not capable of trans-activation. In addition, the activity of the MAT alpha 1-LexA fusion protein is dependent on the functions of the STE7, STE11, and STE12 genes that encode components of the pheromone response pathway.

Amino Acid Sequence↗
PubMed1990

The PRE and PQ box are functionally distinct yeast pheromone response elements.

Saccharomyces cerevisiae mating pheromones function by binding to cell surface receptors and activating signal transduction processes which regulate gene expression. In this report, we have analyzed the minimum sequence requirements for conferring both a and alpha mating pheromone inducibilities onto a heterologous promoter. Here we show that the repetitive pheromone response element (PRE) which binds to STE12 protein is sufficient to confer pheromone responsiveness only when present in multiple copies. Moreover, by itself, it is preferentially responsive to alpha factor in a cells. In contrast, a single copy of the PQ box of the STE3 upstream activation sequence (UAS) is sufficient to confer a-factor responsiveness in alpha cells. The PQ box binds both MCM1 and MAT alpha 1 in a cooperative manner, and neither the P nor Q site alone is sufficient to confer a-factor responsiveness. In a cells, however, even multiple copies of the PQ box fail to confer alpha-factor responsiveness. Therefore, the PRE and the PQ box are functionally distinct pheromone-responsive elements with opposite cell type specificities. Moreover, these results indicate that the MCM1 protein functions in a signal transduction pathway in a manner analogous to that of its mammalian homolog, the serum response factor, which regulates the expression of the c-fos proto-oncogene in mammals.

Base Sequence↗
PubMed1989

Prevention of postdural puncture headache after spinal anaesthesia for extracorporeal shockwave lithotripsy. An assessment of prophylactic epidural blood patching.

The prevention of postdural puncture headache after spinal anaesthesia for extracorporeal shockwave lithotripsy was investigated by a controlled clinical trial which compared epidural injection of 10 ml of autologous blood with 10 ml of normal saline immediately after intrathecal injection of local anaesthetic. The incidence of postdural puncture headache was 8.3% in the group that received blood compared with 45% in the group that received saline, a significant reduction (p less than 0.01). The incidences of backache and lower limb paraesthesiae were similar in both groups. No serious complications were reported.

Adult↗
PubMed1988

Nitrous oxide and day-case laparoscopy: effects on nausea, vomiting and return to normal activity.

Patients admitted for day-case laparoscopy were assigned randomly to receive nitrous oxide-oxygen or oxygen, with enflurane, during a standard anaesthetic technique. Postoperative morbidity, in particular nausea and vomiting, and ability to resume normal activity were assessed over the ensuing 48 h. Supplementary administration of propofol during the operative procedure was required significantly more often (P less than 0.05) in the absence of nitrous oxide. There was no significant difference in the incidence of vomiting before discharge when nitrous oxide was omitted. The incidence and severity of nausea over the 48 h following operation was similar in both groups. There was no difference in analgesic or anti-emetic requirements before discharge and the time taken to resume normal activity was similar. It is concluded that nitrous oxide may be avoided readily in day-case laparoscopy without affecting postoperative morbidity or time taken to return to "street fitness" and normal activity.

Adolescent↗
PubMed1988

The human c-fos serum response factor and the yeast factors GRM/PRTF have related DNA-binding specificities.

One of the elements that mediates growth factor and serum inducibility of the human c-fos gene is a region of dyad symmetry that lies between nucleotides -320 and -299 of the human gene. A mammalian protein specifically binds to this sequence element and has been termed the serum response factor (SRF). Gel-shift analysis and competition experiments demonstrate that there is a factor in the yeast Saccharomyces cerevisiae that binds specifically to the human c-fos SRE. The methylation interference pattern of the yeast factor is identical to that of the mammalian SRF. Regulatory elements of cell-type-specific genes in yeast have homologies to the c-fos SRE and complete for binding of both the mammalian and yeast factors to the SRE. Antisera to the gene product of the MCM1 locus react with the yeast SRE-binding factor. These data suggest that this yeast protein is closely related or identical to the factors [general regulator of mating type (GRM) and pheromone/receptor transcription factor (PRTF)] that are required for the regulation of cell-type-specific genes in yeast.

Cloning, Molecular↗
PubMed1987

Post-operative morbidity associated with the use of atracurium and vecuronium in day-case laparoscopy.

Patients were randomly allocated to receive either vecuronium or atracurium as the sole muscle relaxant for day-case gynaecological laparoscopy to determine if either agent was superior with respect to post-operative morbidity during the 48 h after operation. Intubating conditions and cardiovascular stability were similar in both groups. Post-operative morbidity prior to discharge was also similar except for a significantly higher incidence of abdominal pain in the vecuronium group. There was no statistical difference in specific morbidity during the 48 h after laparoscopy, but a greater number of patients in the vecuronium group was able to resume normal activity 24 h after laparoscopy. Both agents are very suitable for day-case laparoscopies and other short surgical procedures.

Ambulatory Surgical Procedures↗
PubMed1986

Morbidity after day case laparoscopy. A comparison of two techniques of tracheal anaesthesia.

A comparison was made of postoperative morbidity following two anaesthetic techniques for day case laparoscopies. One group of patients was allowed to breathe spontaneously after intubation under suxamethonium. The second group received atracurium and their lungs were mechanically ventilated. Patients in the controlled ventilation group experienced significantly less severe sore throats and muscle pain in the first 24 hours postoperatively than the patients who breathed spontaneously. Both techniques proved to be safe and are suitable for day case laparoscopy. The safety of patients is discussed in relation to the choice of anaesthetic technique used.

Adult↗
PubMed1984

The effect of labour and epidural analgesia on pain threshold.

Pain thresholds were measured using forehead pressure in 30 women before amniotomy and then during labour up to the point of their requesting analgesia. Measurements continued subsequently only in those having epidural analgesia alone. No significant change in pain threshold was seen in any patient up to the administration of analgesia, nor thereafter in the ten patients having epidurals. This study fails to confirm previous reports in animals of significant rises in pain threshold during parturition. It calls into question the view that previously reported changes in plasma endorphin levels may be associated with altered pain thresholds.

Anesthesia, Epidural↗
PubMed1983

Foot drop, mimicking neuritic leprosy induced by a Baker's cyst.

A Baker's cyst of the left knee joint induced foot drop insidiously in a male, Hindu, aged 25 years. On clinical suspicion, that this malady was caused by neuritic type of leprosy, he was administered antileprosy drugs for 6 months without any benefit. On exploration a globular cystic mass, containing gelatinous fluid, was seen to be pressing over the left lateral popliteal nerve. Following removal of this mass, which on histology confirmed to be a Baker's cyst, foot drop and associated motor power impairment disappeared. This case thus highlights the importance of an early exploration and histological diagnosis of a suspected case of neuritic leprosy inducing foot drop and progressively deteriorating, inspite of regular antileprosy therapy.

Adult↗
PubMed1983

Leiomyoma cutis.

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Adolescent↗