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Biomedical subjects

S Raina

Publications and source records attributed to S Raina.

At least 55 records · Page 3Linked to original sources
PubMed1991

The htrM gene, whose product is essential for Escherichia coli viability only at elevated temperatures, is identical to the rfaD gene.

We have identified a new E. coli gene, htrM. The htrM gene was identified because its insertional inactivation by the Tn5 transposon results in E. coli's inability to form colonies at temperatures above 43 degrees C. The corresponding htrM+ gene was cloned on the basis of its ability to correct the temperature-sensitive phenotype of the htrM::Tn5 insertion mutations. The htrM gene has been mapped to 81.2 min on the conventional E. coli genetic map. It was sequenced and shown to code for an acidic, 34,893-Da polypeptide. Three transcriptional starts were located 48, 90 and 123 nucleotides upstream of the ATG, initiation codon referred to as the P1, P2 and P3(hs) promoters, respectively. The -10 and -35 regions of the P1 promoter bear a close similarity to the E sigma 70-recognized consensus sequences, while the -12 region of the P2 promoter resembles the consensus promoter sequence transcribed by the rpoN gene product. Transcripts of the htrM gene accumulate with increasing temperature. The -10 and -35 regions of the P3(hs) promoter, represented by nucleotides 160 to 130 upstream of the ATG initation codon, are similar to the E sigma 32-recognized consensus sequences. The sigma 32 transcription factor is essential for maximal htrM gene transcription, since htrM RNA transcripts are made at reduced rates in a rpoH null mutant background. Surprisingly, the htrM gene turns out to be identical to rfaD, whose product is required for the biosynthesis of the ADP-L-glycero-D manoheptose lipopolyaccharide precursor [Pegues et al. (1990) J. Bacteriol. 172, 4652-4660].

Amino Acid Sequence↗
PubMed1991

Identification of the Escherichia coli sohB gene, a multicopy suppressor of the HtrA (DegP) null phenotype.

We cloned and sequenced the sohB gene of Escherichia coli. The temperature-sensitive phenotype of bacteria that carry a Tn10 insertion in the htrA (degP) gene is relieved when the sohB gene is present in the cell on a multicopy plasmid (30 to 50 copies per cell). The htrA gene encodes a periplasmic protease required for bacterial viability only at high temperature, i.e., above 39 degrees C. The sohB gene maps to 28 min on the E. coli chromosome, precisely between the topA and btuR genes. The gene encodes a 39,000-Mr precursor protein which is processed to a 37,000-Mr mature form. Sequencing of a DNA fragment containing the gene revealed an open reading frame which could encode a protein of Mr 39,474 with a predicted signal sequence cleavage site between amino acids 22 and 23. Cleavage at this site would reduce the size of the processed protein to 37,474 Mr. The predicted protein encoded by the open reading frame has homology with the inner membrane enzyme protease IV of E. coli, which digests cleaved signal peptides. Therefore, it is possible that the sohB gene encodes a previously undiscovered periplasmic protease in E. coli that, when overexpressed, can partially compensate for the missing HtrA protein function.

Amino Acid Sequence↗
PubMed1991

The Escherichia coli htrP gene product is essential for bacterial growth at high temperatures: mapping, cloning, sequencing, and transcriptional regulation of htrP.

We identified and characterized a new Escherichia coli gene, htrP. The htrP gene was identified because its insertional inactivation by the Tn10 transposon results in the inability of E. coli to form colonies at temperatures above 37 degrees C and a slow growth phenotype at 30 degrees C. The htrP gene was cloned and mapped to 66.3 min on the E. coli genetic map, 4 kbp clockwise from the tolC gene. The htrP gene was sequenced and shown to code for an acidic, 27,471-Da polypeptide and to be transcribed counterclockwise with respect to the genetic map. The predicted HtrP protein has two potential transmembrane segments and shares an identity of 64.4% over a length of 210 amino acids with the LuxH protein. Despite the fact that the htrP gene is essential for E. coli growth exclusively at high temperatures, the levels of htrP-specific transcripts decrease with increasing temperature.

Amino Acid Sequence↗
PubMed1990

Multimodality preoperative treatment for advanced stage IV (MO) cancer of the head and neck.

Sixty-three patients with advanced unresectable squamous cell carcinoma of the head and neck were treated with a combination of chemotherapy, radiation, and surgery. We observed a 75% response to neoadjuvant chemotherapy. The 5-year survival rate for all 63 patients was 20%, and only 3 patients were alive at 8 years. The 5-year survival rate for patients who completed the treatment plan and received chemotherapy, radiation, and surgery was 43% compared with 20% for those who had chemotherapy and radiation but refused surgery. Development of a second primary cancer was the cause of death in 62% of the patients who survived more than 24 months.

Carcinoma, Squamous Cell↗
PubMed1990

A new Escherichia coli heat shock gene, htrC, whose product is essential for viability only at high temperatures.

We identified and characterized a new Escherichia coli gene, htrC. Inactivation of the htrC gene results in the inability to form colonies at 42 degrees C. An identical bacterial phenotype is found whether the htrC gene is inactivated either by Tn5 insertions or by a deletion spanning the entire gene. The htrC gene has been localized at 90 min, immediately downstream of the rpoC gene, and has been previously sequenced. It codes for a basic polypeptide with an Mr of 21,130. The htrC gene is under heat shock regulation, since it is transcribed actively only in bacteria possessing functional sigma 32. Inactivation of htrC results in (i) bacterial filamentation at intermediate temperatures, (ii) cell lysis at temperatures above 42 degrees C, (iii) overproduction of sigma 32-dependent heat shock proteins at all temperatures, (iv) overproduction of a few additional polypeptides, (v) underproduction of many polypeptides, and (vi) an overall defect in cellular proteolysis as judged by the reduced rate of puromycyl polypeptide degradation. In addition, the presence of an htrC mutation eliminates the UV sensitivity normally exhibited by lon mutant bacteria.

Amino Acid Sequence↗
PubMed1987

Lung cancer in patients with head and neck cancer. Incidence and long-term survival.

Of the 3,907 cases of primary head and neck or lung cancer diagnosed between 1961 and 1984, 94 patients were identified with a history of cancer at both sites. The total incidence of lung cancer in our head and neck cancer patients was 5.4 percent. Of the 94 patients, 73 had both cancers diagnosed at our institution. These 73 patients were further analyzed. Squamous cell carcinoma accounted for 63 percent of the lung cancers. Twenty of the lung cancers were synchronous and 47 were metachronous after head and neck cancer. Of the synchronous lung cancers, 50 percent were postoperative stage I, whereas only 11 percent of the metachronous cancers were postoperative stage I. The lung cancer survival rate was significantly better for the synchronous cancer group at 5 years (34 percent) than for the metachronous cancer group (5 percent). The better survival rate was evidently due to the greater proportion of early-stage lung lesions. The relatively large number of advanced-stage lung lesions in the metachronous cancer group suggests that aggressive screening of head and neck cancer patients for lung cancer may detect more metachronous lung cancers at an earlier stage and thus improve the survival rate of these patients.

Follow-Up Studies↗
PubMed1986

Limitations in testing for attitudes toward cancer.

A Cancer Attitude And Knowledge Questionnaire was administered to two groups of incoming first year medical students and to one of these groups at the end of their second year. The same questionnaire, except for the questions dealing with cognitive knowledge, was also used to assess the attitudes of practicing oncologists. There was a wide variation in the responses to the attitudinal items in all groups. In view of many inconsistencies in the results, a rigorous analysis of the instrument was carried out. The subscales derived from the Cancer Attitude Survey were found to lack adequate reliability. The only part of the attitudinal test found to be reliable and discriminatory was the semantic differential developed by the authors. It is, therefore, concluded that the currently used techniques are inadequate, and there is a need for a new multidimensional approach to the assessment of attitudes toward cancer.

Attitude of Health Personnel↗
PubMed1986

Current attitudes in the management of obstructive biliary tract disease.

The current attitudes of surgeons towards the management of obstructive biliary tract disease were assessed by analyzing the responses of general surgeons to a 20-item questionnaire. The responses indicate that ultrasound is the most favored initial diagnostic test for suspected choledocolithiasis. Ninety-nine per cent of the respondents always or almost always insert a T-tube following exploration of the common bile duct for stones. For patients with stone impacted at the ampulla of Vater, sphincterotomy with or without sphincteroplasty is recommended by 86 per cent of surgeons. However, differences are noted in the approach to management of malignant lesions in the biliary tract. For carcinoma of the head of the pancreas, at laparotomy, if the lesion is resectable, 59 per cent of the surgeons will perform a Whipple procedure, nine per cent a total pancreatectomy, and 28 per cent recommend bypass only. For unresectable carcinoma of the head of the pancreas, 73 per cent perform cholecystojejunostomy, and 26 per cent prefer choledocojejunostomy. In addition to the biliary bypass, only 57 per cent perform a gastric bypass routinely. The favored treatment (62%) for unresectable common bile duct tumors is an internal bypass. However, following bypass, only 45 per cent recommend further treatment with radiation and/or chemotherapy. Therefore, it appears that there is agreement on the treatment of biliary obstruction due to stones. Differences are noted, however, in the approach to the management of malignant disease.

Attitude of Health Personnel↗
PubMed1986

Celestin dilatation of benign esophageal strictures: a review of 100 patients.

Over the last 4 yr 302 Celestin dilatations have been performed in 100 patients with benign esophageal strictures. Patients presenting with tighter strictures have a significantly increased need for subsequent dilatation (p less than 0.001). The technique described permits rapid turnover of patients in the endoscopy suite and may be used in even the most elderly patients.

Aged↗
PubMed1985

Preoperative intra-arterial infusion chemotherapy for advanced squamous cell carcinoma of the mouth and oropharynx.

Twelve patients with advanced locoregional (Stage III and IV) squamous cell carcinoma of the oral cavity and oropharynx underwent treatment with cisplatin, vinblastine, bleomycin, and 5-fluorouracil, given by intra-arterial infusion, as primary adjuvant therapy, in preparation for radiation therapy and surgery. Responses were observed during or immediately after infusion therapy in 8 of 12 (67%) of patients (1 complete response, 7 partial responses). Infusion chemotherapy was followed by radiation therapy alone in five patients and by radiation and surgery in six patients. The protocol was initiated in August 1981, and six patients are now free of their primary cancer, at 21 to 36 months, whereas six have died with disease. Arterial infusion of a combination of effective antineoplastic agents is a promising method for the preparation of selected patients for radiation therapy and surgery, as it is less likely to produce serious systemic toxicity and it requires a shorter period than systemic neoadjuvant chemotherapy.

Aged↗
PubMed1985

Trends in the management of breast cancer.

Responses of general surgeons to a questionnaire on breast cancer were analyzed to determine the current trends in the management of this disease. A 21-item questionnaire was mailed to members of the New Jersey Chapter of the American College of Surgeons in 1982 and the responses, received on noncoded, anonymous answer sheets, were analyzed for frequency distribution. These responses were compared to previously recorded responses to the same questions for 1971 and 1977. Seventy-six percent of the respondents in 1982 performed needle aspirations often or always, compared to 36% in 1971 and 80% in 1977. The use of routine mammography has increased from 16% in 1971 and 20% in 1977 to 38% in 1982. Modified radical mastectomy is now the most common type of procedure employed in the management of stage I breast cancer, with 89% of respondents in favor of this approach compared to 15% in 1971 and 60% in 1977. Fifty-nine percent of the respondents are not opposed to breast reconstruction following mastectomy versus 14% in 1971 and 49% in 1977. For patients with axillary nodes, chemotherapy with multiple agents was recommended by 76% of general surgeons in 1982, compared to 58% in 1977. These results indicate a continuing trend towards increasing use of needle aspiration and routine mammography for diagnosis and for employment of chemotherapy with multiple agents in the adjuvant treatment of patients with positive axillary nodes. Furthermore, modified radical mastectomy is the operation of choice for stage I cancer of the breast for increasing numbers of surgeons.

Breast Neoplasms↗
PubMed1985

Effect of surgery on tumor-induced accelerated coagulation in a rat carcinoma.

Accelerated coagulation detected by thromboelastography has been reported in early stages of tumor growth. The present investigation was conducted to determine the changes in tumor-induced accelerated coagulation following complete and partial resection of the tumor. Male Fisher rats were divided into four groups: (1) control, (2) tumor-bearing rats, (3) complete resection, (4) partial resection. In groups 2, 3, and 4 a 2-mm3 piece of squamous cell carcinoma (NCI 11095) was implanted subcutaneously in the left flank. Seven days later blood samples were obtained from the tumor and control groups and tested on a thromboelastograph to determine the effect of the tumor on the coagulation of the hosts. Six weeks following the initial tumor implantation a sham operation was performed on group 2, complete resection on group 3, and a partial resection on group 4. After a rest period of 3 weeks blood samples were obtained from the four groups of rats and tested on a thromboelastograph. The results indicate that there is a significant acceleration of coagulation in tumor-bearing animals. The effect of surgery on this tumor-induced phenomenon depends on the type of procedure performed. Complete resection returns the coagulation status toward normal whereas sham operation or a partial resection do not. In this tumor model, hypercoagulability of the blood, therefore, indicates the presence of residual tumor.

Animals↗
PubMed1985

Changing attitudes toward management of cancer of the colon and rectum.

Changes in the attitudes of surgeons toward the management of cancer of the colon and rectum over a 5-year period were assessed by analysis of responses of general surgeons to a 21-item questionnaire on colon cancer from 1978 and 1983. Comparisons of the responses revealed that the use of routine preoperative liver scans has decreased from 57 to 45 per cent. Transanal resection of villous adenoma of the rectum is used more often (44% in 1983 versus 34% in 1978). For obstructing carcinoma of the colon, a two-stage procedure is used more often, with 46 per cent of the respondents in favor of this approach in 1983 compared with 29 per cent in 1978. The use of staplers for colon anastomoses following resection has also increased with 44 per cent surgeons in 1983 using this technique always or frequently compared with 21 per cent in 1978. Following anterior resection, 66 per cent of respondents in 1983 seldom or never use a transverse colostomy (54% in 1978). The number of surgeons closing the perineal wound over suction drains following an abdominoperineal resection has increased from 46 per cent (1978) to 63 per cent in 1983. Sphincter-saving procedures for carcinoma of the rectum are used by a large number of surgeons in 1983 (29% versus 9% in 1978). An increase is noted in the use of preoperative radiation therapy for selected cases of rectal cancer (53% in 1978 to 68% in 1983).(ABSTRACT TRUNCATED AT 250 WORDS)

Attitude of Health Personnel↗
PubMed1985

A simplified technique for gastric and duodenal decompression for duodenal injuries.

A simplified effective method of the decompression for use after repair of duodenal injuries is described. A Moss esophagogastric decompression tube is inserted as a gastrostomy to provide decompression of stomach and duodenum through a single tube. In addition, the complications associated with long-term nasogastric tube drainage are avoided.

Drainage↗
PubMed1984

The incidence of metastases after multimodal therapy for cancer of the head and neck.

Combined therapeutic regimens integrating chemotherapy, radiation therapy, and surgery are reported to be effective in treating advanced squamous cell carcinomas of the head and neck. The current study evaluates 58 consecutive patients with advanced (T4, N3) head and neck cancers. Forty patients (multimodal group) were treated with 2 courses of chemotherapy (cisplatin 2 mg/kg; methotrexate 280-560 mg/m2 with leucovorin rescue; bleomycin 30 mu X 3) followed by radiation therapy and surgery. Eighteen patients (combined group) were treated with preoperative radiation therapy followed by surgery. In the multimodal group there were 27 (67.5%) partial responses and nine (22.5%) complete responses, for an overall response rate of 90%. Response rates by site of primary lesion were: oral cavity, 11 of 11; oropharynx, 13 of 17; hypopharynx, 5 of 5; and larynx 7 of 7. Distant metastases (skin, lung, bone, central nervous system [CNS]) appeared in 16 patients (40%) (P less than 0.05 versus combined) at a median time of 8.5 months after diagnosis, 15 in patients having a partial (11) or complete (4) response. Thirteen patients (33%) developed distant metastases within 1 year of diagnosis (P less than 0.05 versus combined). In 11 of these patients, the primary lesion and neck disease were resectable. Two thoracotomies were performed for solitary pulmonary metastases; one was resected for cure. Fifteen patients (38%) underwent curative resection; 11 (73%) were alive at 1 year, and ten (67%) were free of disease. Overall survival was 20 of 40 (50%) at 1 year. In the combined group, there were 14 partial responses (78%) and no complete responses. Early distant metastases appeared in two patients (12.5%), at 2 and 6 months after diagnosis. Seven patients (38%) underwent curative resection; six of seven (86%) were alive at 1 year, four of seven (57%) were disease-free. Six of 16 patients at risk (37.5%) survived 1 year. After combined therapy, six of ten patients (60%) with responses to therapy survived 1 year versus 12 of 20 responders (57%) without distant metastases in the multimodal group. It is concluded that multimodal therapy for advanced head and neck cancer results in a higher response rate than with conventional combined therapy. The incidence of early and postoperative distant metastases was increased after the multimodal regimen. At 1 year there were no differences in survival between the combined and multimodal groups for responders without early metastases. Further observation is needed to determine the net long-term effects of this regimen. A prospective randomized comparison of combined and multimodal therapy for advanced lesions is indicated.

Antineoplastic Combined Chemotherapy Protocols↗