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Biomedical subjects

M K Roy

Publications and source records attributed to M K Roy.

At least 37 records · Page 2Linked to original sources
PubMed1998

Complications of latissimus dorsi myocutaneous flap breast reconstruction.

AIMS: To review the experience of a single unit in post-mastectomy reconstruction using the latissimus dorsi flap. METHODS: A retrospective review of 111 cases treated between 1984 and 1993. The notes were evaluated for type of procedure, associated treatment and complications. RESULTS: A significant morbidity of this procedure was demonstrated with 41 (37%) patients requiring a second operation during the period of the study. The majority of these second operations were related to the prosthesis used to achieve symmetry. Second operations were more common in those who had saline-filled prostheses. Other complications seen included wound infection, small areas of flap necrosis, hypertrophic scars and problems with the donor scar. No differences in complication rates were demonstrated for delayed vs immediate procedures or for patients receiving or not receiving radiotherapy. No life-threatening complication were seen during the study. CONCLUSIONS: The latissimus dorsi reconstruction is reliable but the overall programme is beset with considerable morbidity. This factor needs to be taken into consideration when discussing reconstructive options with the post-mastectomy patient.

Adult↗
PubMed1998

Laparoscopic cholecystectomy in multiple laparotomy Crohn's disease.

Patients with complicated Crohn's disease often require several surgical procedures resulting in multiple adhesions. They also have an increased incidence of gallstones. Laparoscopic cholecystectomy is associated with several advantages but is problematic for the inexperienced surgeon in the presence of multiple adhesions. Laparoscopic cholecystectomy was performed successfully in three patients with Crohn's disease who had previous extensive abdominal surgery. The average operative time was 75 min, with an average hospital stay of 2 days and minimal blood loss. There were no postoperative complications. Provided specific precautions are taken during establishment of the pneumoperitoneum, an adequate adhesiolysis can be performed, rendering laparoscopic cholecystectomy feasible and safe in such patients.

Cholecystectomy, Laparoscopic↗
PubMed1997

Possible involvement of plasmids in degradation of malathion and chlorpyriphos by Micrococcus sp.

Two plasmid-harboring strains of Micrococcus sp. (M-36 and AG-43) degrade malathion and chlorpyriphos. Derivatives of the strains (SDS-36 and AO-43) treated with acridine orange and sodium dodecyl sulfate could not utilize malathion and chlorpyriphos for growth as the sole carbon source. Agarose gel electrophoresis of cell extracts of M-36 and AG-43 revealed the presence of a plasmid which was absent in SDS-36 and AO-43--suggesting probable involvement of plasmids in the degradation of malathion and chlorpyriphos by M-36 and AG-43. Nalidixic acid resistance in M-36 was also lost upon elimination of plasmids.

Acridine Orange↗
PubMed1997

Characterization of Streptomyces sp. strain DRS-1 and its ampicillin transformation product.

Incubation of ampicillin with whole cells of Streptomyces sp. DRS-1 resulted in accumulation of four compounds different from ampicillin. One of them was isolated, purified and partially characterized. On the basis of spectroscopic characteristics, RF value and antibacterial activity the compound was identified as cephalexin. It could also be obtained from ampicillin by using crude protein extract of the strain.

Ampicillin↗
PubMed1997

Multiple antibiotic resistance (MAR) index and its reversion in Pseudomonas aeruginosa.

The MAR indexes of hospital isolates of Pseudomonas aeruginosa were determined with reference to nine different cephalosporins. The values for all the strains were higher than 0.2 suggesting their origin from a high risk source of contamination where antibiotics are often used. Emergence of MAR pathogenic strains of Ps. aeruginosa indicated possible nosocomial infection in the hospital environment. beta-Lactamases produced by these organisms were tested and their inhibition by clavulanic acid was studied. beta-Lactamase produced by one of these strains (Ps-1) could not be inhibited by clavulanic acid whereas beta-lactamases of three other strains (Ps-2, Ps-3 and Ps-4) could be inhibited by clavulanic acid in the presence of cephalosporins, suggesting a possible use of clavulanic acid in combination with cephalosporins, to combat beta-lactamase induced resistance in Ps. aeruginosa.

Anti-Bacterial Agents↗
PubMed1997

Crohn's disease presenting with acute colonic perforation.

Crohn's disease is well known for its multiple intestinal complications. The chronic nature and fibrous inflammation which invariably accompanies this disease explains the relative rarity of free intestinal perforation. The true incidence of free bowel perforation is difficult to assess but 1-2% is the anticipated occurrence during the course of illness. We present a case of Crohn's disease which presented for the first time with acute colonic perforation, an extremely rare entity, and review the current world literature.

Acute Disease↗
PubMed1996

Steroid transformation by mutants of Mycobacterium sp. with altered response to antibiotics.

Mycobacterium sp. NRRLB3683 which is capable to convert beta-sitosterol to 1,4-androstadiene-3,17-dione (ADD) was treated with methyl methane sulfonate and two strains with altered sensitivity to various antibiotics were obtained. One of the strain was steroid 1(2)-dehydrogenase negative and the other positive. Efficiency of utilization of sterols followed the order beta-sitosterol > cholesterol > soluble cholesterol. The steroid 1(2)-dehydrogenase negative strain was capable of producing 17KS (AD) from beta-sitosterol and converting AD to testosterone and ADD to AD suggesting the negative role of 1(2)-dehydrogenase in sterol side chain cleavage and decrease in hydrogenase activity by mutation. But this enzyme can perform the reverse reaction under aerobic condition.

Androstenedione↗
PubMed1996

Carcinoma of the oesophagus: the time for a multidiciplinary approach?

Oesophageal cancer is one of the most lethal carcinomas, with 5-year survival rates of less than 5%. This is due to a combination of factors including late presentation, associated cardiac and respiratory disease, and the technical difficulties of resectional surgery. The outcome for patients with oesophageal cancer has changed little in recent years, perpetuating a pervading attitude of pessimism in the surgical community. The epidemiology of oesophageal cancer is changing with the increasing incidence of adenocarcinoma. Most of these tumours arise in the setting of Barrett's oesophagus and chronic gastro-oesophageal reflux disease. Survival following surgery for oesophageal cancer is determined by several independent factors, most notably the pathological stage of the disease and the patients physiological status. However, in patients with limited disease, in particular patients with less than five lymph node metastases, the extent of the nodal dissection positively impacts survival. This article reviews the changing epidemiology of oesophageal cancer, focusing on the need for early diagnosis and the selection of patients for surgery. It places emphasis on the importance of integrating surgical therapy in a multidisciplinary team approach to the management of such patients.

Adenocarcinoma↗
PubMed1994

Validity of new phage typing scheme against Vibrio cholerae 01 biotype ElTor strains.

A total of 538 strains of V. cholerae 01 biotype ElTor were phage typed by the conventional Basu and Mukerjee and also the new typing scheme developed at the National Institute of Cholera and Enteric Diseases, Calcutta. The strains could be clustered into seven types by the new scheme as against only two by the conventional method. The results provide conclusive evidence on the validity of the new scheme for phage typing of V. cholerae strains.

Bacteriophage Typing↗
PubMed1993

New phage typing scheme for Vibrio cholerae O1 biotype El Tor strains.

The conventional phage typing scheme proposed by S. Basu and S. Mukerjee (Experientia 24:299-300, 1968) has been used routinely for identification of the strains at the Vibrio Phage Reference Laboratory since 1968. However, because of limitations of this scheme, a new phage typing scheme using five newly isolated phages was incorporated into the conventional scheme. A different definition of routine test dilution (almost confluent lysis) was found to be more useful than the one previously used (confluent lysis). The 1,000 strains tested could be clustered into 27 types with the five new phages. With the new scheme of 10 phages (5 new phages and 5 phages of Basu and Mukerjee), the 1,000 strains could be grouped into 146 types. The new phages were different from each other and also from those of Basu and Mukerjee, as revealed by lytic pattern, electron microscopy, restriction endonuclease digestion, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and antiphage antiserum studies. With the new typing scheme, 99.6% of the strains were typeable. Phage type 115 was the most common and includes 119 (11.9%) of the 1,000 strains tested. Next most common were phage types 142 (9.4%), 143 (7.0%), 104 and 116 (both 5.4%), 3 (5.3%), 5 (4.1%), 4 (3.9%), 24 (2.1%), and 100 (1.7%). The larger number of types would be useful for further classification of the strains for epidemiological purposes. This newly developed scheme is highly applicable to, and could be widely adopted for, phage typing of Vibrio cholerae O1 biotype El Tor strains.

Antibodies, Viral↗
PubMed1992

Metabolic blocks in the degradation of beta-sitosterol by a plasmid-cured strain of Arthrobacter oxydans.

Plasmid-harbouring, sterol-decomposing organism Arthrobacter oxydans 317 was treated with sodium dodecylsulphate to obtain a plasmid-cured strain A. oxydans 317 A1 incapable of utilizing 4-androstene-3,17-dione (AD). The strain 317 A1 was unable to degrade beta-sitosterol side chain completely to form AD but could carry out partial degradation as shown by the accumulation of 3-oxochol-4-en-24-oic acid as a major metabolite and 27-norcholest-4-en-3,24-dione as a minor metabolite. The strain could form 1,4-androstadiene-3,17-dione (ADD) from 3-oxo-23,24-bisnorchol-1,4-dien-22- oic acid (BNC) to a limited extent. The existence of metabolic blocks in the conversion of 3-oxochol-4-en-24-oic acid to 3-oxo-23,24-bis-norchol-4-en-22-oic acid and further conversion to AD by the plasmid-cured strain 317 A1 was suggested. Neither the formation of ADD from AD nor the conversion of AD and ADD to 9 alpha-hydroxy derivatives leading to steroid ring opening could be done by the plasmid-cured strain but the 17 beta-reduction of AD and ADD and 1(2)-reduction of ADD were not affected by the absence of the plasmid. It was proposed that plasmid determines 1(2)-dehydrogenation and 9 alpha-hydroxylation of steroid ring structure in this organism.

Androstadienes↗
PubMed1992

Physical trauma and tungsten toxicity reduce the efficiency of biolistic transformation.

A cell suspension culture of tobacco (Nicotiana tabacum L.) was used as a model to study injury to cells during biolistic transformation. Lawns of cells were bombarded with tungsten particles that were coated with a plasmid containing the beta-glucuronidase and the neomycin phosphotransferase II genes. When a gunpowder-driven biolistic device was used, numerous transiently expressing cells were focused around the epicenter of the blast which was manifested by a hole blown in the filter paper supporting the cells. However, transformed cells nearest the blast epicenter were injured and could not be recovered as stable transformants. The injury was primarily caused by physical trauma to the cells from gas blast and acoustic shock generated by the device. Postlaunch baffles or meshes placed in the gunpowder device reduced cell injury and increased the recovery of kanamycin-resistant colonies 3.5- and 2.5-fold, respectively. A newly developed helium-driven device was more gentle to the cells and also increased the number of transformants. Cell injury could be further moderated by using a mesh and a prelaunch baffle in the helium device. Toxicity of the tungsten microprojectiles also contributed to cell injury. Gold microprojectiles were not toxic and resulted in fourfold more kanamycin-resistant colonies than when similar quantities of similarly sized tungsten particles were used.

Journal Article↗