Biomedical subjects

D Cavanagh

Publications and source records attributed to D Cavanagh.

At least 73 records · Page 4Linked to original sources

PubMed1995

Characterization of the transmissible gastroenteritis virus (TGEV) transcription initiation sequence. Characterization of TGEV TIS.

The ability of the TGEV transcription initiation sequence (TIS) to produce subgenomic RNAs was investigated by placing a reporter gene, chloramphenicol acetyltransferase (CAT) under the control of either the mRNA 6 or the mRNA 7 TISs. Both constructs only produced CAT in TGEV infected cells and the amount of CAT produced from the mRNA 7 TIS was less than from the mRNA 6 TIS. Mutations were made within and around the TISs and the effect on CAT production assayed. THe results showed that the TGEV TIS acted as a initiator of transcription for CAT, though the degree of base pairing between the TIS and leader RNA was not the only factor implicated in the control transcription.

Animals↗

PubMed1995

First experimental evidence of recombination in infectious bronchitis virus. Recombination in IBV.

A high frequency of recombination has been shown to occur during replication of the coronavirus mouse hepatitis virus (MHV) in vitro as well as in vivo. Although sequencing of field strains of coronavirus infectious bronchitis virus (IBV) has indicated that IBV strains also undergo recombination, there has been no experimental evidence to support this deduction. To investigate whether recombination occurs in IBV, embryonated eggs were coinfected with IBV-Beaudette and IBV-M41. Potential recombinants were detected by strain-specific polymerase chain reaction (PCR) amplifications, using oligonucleotides corresponding to regions in the 3' end of the genome. Sequencing of the PCR products confirmed that a number of recombinations had occurred between the two strains.

Animals↗

PubMed1995

Generation of a defective RNA of avian coronavirus infectious bronchitis virus (IBV). Defective RNA of coronavirus IBV.

The Beaudette strain of IBV was passaged 16 times in chick kidney (CK) cells. Total cellular RNA was analyzed by Northern hybridization and was probed with 32P-labeled cDNA probes corresponding to the first 2 kb of the 5' end of the genome, but excluding the leader, and to the last 1.8 kb of the 3' end of the genome. A new, defective IBV RNA species (CD-91) was detected at passage six. The defective RNA, present in total cell extract RNA and in oligo-(dT)30-selected RNA from passage 15, was amplified by the reverse transcription-polymerase chain reaction (RT-PCR) to give four fragments. The oligonucleotides used were selected such that CD-91 RNA, but not the genomic RNA, would be amplified. Cloning and sequencing of the PCR products showed that CD-91 comprises 9.1 kb and has three regions of the genome. It contains 1133 nucleotides from the 5' end of the genome, 6322 from gene 1b corresponding to position 12423 to 18744 in the IBV genome and 1626 from the 3' end of the genome. At position 749 one nucleotide, an adenine residue, was absent from CD-91 RNA. By Northern hybridization CD-91 RNA was detected in virions in higher amounts than the subgenomic mRNAs.

Animals↗

PubMed1995

Atrial natriuretic factor in gynecologic malignancy.

OBJECTIVE: To determine whether plasma atrial natriuretic factor (ANF) levels are different in patients with gynecologic malignancy compared with those in healthy, nonpregnant women, and if differences do exist, whether chemotherapy plays a role. METHODS: We compared the plasma levels of ANF in nonpregnant women free of malignancy (group 1, n = 25) and in patients with malignancy receiving at least one course of platinum-based chemotherapy (group 2, n = 32). To differentiate the contributory role of chemotherapy, another group of patients (group 3, n = 18) was studied before the initiation of chemotherapy. RESULTS: The ANF values (mean +/- standard error [SE]) in groups 1, 2, and 3 were 7.3 +/- 0.3, 13.8 +/- 0.8, and 14.6 +/- 1.8 fmol/mL of plasma, respectively. Significant differences (P < or = .001) occurred between groups 1 and 2 and 1 and 3, but not between 2 and 3. In comparing groups 2 and 3 for a specific type of cancer, there were no significant differences. The respective values (mean +/- SE) for endometrial, ovarian, and cervical cancer before chemotherapy were 9.9 +/- 1.7, 15.05 +/- 2.6, and 18.5 +/- 4.3 fmol/mL. After chemotherapy, the values remained at 9.3 +/- 1.5, 15.03 +/- 1.06, and 14.6 +/- 2.2 fmol/mL, respectively. CONCLUSION: Plasma ANF levels in gynecologic cancer patients were significantly higher than those in healthy, nonpregnant women. Levels were higher before chemotherapy started, thus negating the idea that chemotherapy may initiate the production and release of ANF.

Adult↗

PubMed1995

Quantification of individual subgenomic mRNA species during replication of the coronavirus transmissible gastroenteritis virus.

A biotinylated-oligonucleotide-based method was used to isolate the subgenomic mRNAs of the coronavirus transmissible gastroenteritis virus (TGEV) to investigate the amounts of the mRNAs produced at early, middle and late times in the replication cycle. TGEV mRNA 6, which encodes the N protein, was observed to be the most abundant species throughout the replication cycle. The ratios of mRNA 6 to the other mRNAs were 1:0.11 (mRNA 2), 1:0.16 (mRNAs 3 and 4) and 1:0.37 (mRNA 5) at 12 h post-infection. All the mRNA species were differentially regulated throughout the replication cycle, although the rate of accumulation of mRNAs 4, 5 and 6, but not mRNA 3, increased markedly towards the end of the replication cycle. mRNA 7 was not detected in the system used. There was no observable correlation between the amounts of each mRNA synthesised and the potential degree of base pairing between the 3' end of the leader sequence and the transcription associated sequences on the genomic RNA at any time during the replication cycle. This indicates that the extent of base pairing was not the only factor involved in the control of subgenomic mRNA synthesis.

Animals↗

PubMed1995

Sequence and in vitro expression of the phosphoprotein gene of avian pneumovirus.

The phosphoprotein (P) gene of two subgroup A strains of avian pneumovirus comprised 855 nucleotides containing only one substantial open reading frame encoding a protein of 278 amino acids, with a predicted M(r) of 30,323. In vitro translation of P mRNA in a wheat germ system resulted in the synthesis of two polypeptides of M(r) 35,000. Comparison of the deduced P protein sequence with that of the known mammalian pneumoviruses revealed overall amino acid identities ranging from 31 to 34.5%, suggesting a distant relationship. However, there was a much higher identity (63.2-68.4%) in a region of 57 residues, which included a heptad repeat sequence.

Amino Acid Sequence↗

PubMed1995

Cloning and sequencing of a 8.4-kb region from the 3'-end of a Taiwanese virulent isolate of the coronavirus transmissible gastroenteritis virus.

The nucleotide sequence (8396 nucleotides) was determined, from the 3'-end of the putative polymerase gene to the poly(A) tail, for a Taiwanese virulent isolate, TFI, of transmissible gastroenteritis virus (TGEV). The TFI nucleotide sequence had very high identity to the British virulent field isolate FS772/70 (98.3%), the attenuated Purdue 115 (96.7%) and from the S gene to ORF-4 gene region, to the low passaged virulent Miller (98.3%) strains of TGEV. Comparison of the TFI S protein sequence with those determined from other TGEV strains and those of the TGEV variant, porcine respiratory coronavirus, isolated from Europe and North America showed that they had changed very little over a period of 4 decades. The two extra amino acids found to be present in the spike proteins of the virulent FS772/70 and Miller strains when compared to the avirulent Purdue strain were found to be present in the TFI strain. The genomic organisation of the TFI strain was the same as that of the other TGEV viruses.

Animals↗

PubMed1995

A region of the coronavirus infectious bronchitis virus 1a polyprotein encoding the 3C-like protease domain is subject to rapid turnover when expressed in rabbit reticulocyte lysate.

In order to investigate the mechanisms involved in the processing of infectious bronchitis virus polyproteins, several candidate regions of the genome have been cloned and expressed in vitro. During these studies it was observed that the translation product encoded by one of these clones (pKT205) was poorly expressed. Biochemical and genetic analyses revealed that the basis for the poor expression was a post-translational event involving ubiquitination of the protein and degradation by an ATP-dependent system operating in the reticulocyte lysate used for the in vitro expression. Two independently acting regions which conferred instability were identified, one of which mapped to the predicted 3C protease domain, contained within the 5' end of the clone, while the other, more C-terminal region, was effective in conferring instability upon a heterologous protein to which it had been transferred. These regions may influence the stability of the authentic viral protein(s) in vivo and hence allow for the control of their expression and/or function at the level of proteolysis by cellular protease(s).

3C Viral Proteases↗

PubMed1995

Novel organization of the site-specific integration and excision recombination functions of the Staphylococcus aureus serotype F virulence-converting phages phi 13 and phi 42.

Functions required for site-specific integration and excision of the Staphylococcus aureus serotype F virulence-converting phages phi 13 and phi 42 were localized and characterized. Like other temperate phages, integration of phi 13 and phi 42 sequences was found to require the product of an int gene located close to the phage attP site. Both int genes are almost identical, express proteins possessing characteristic features of the Int (integrase) family of recombinases, but share very little homology with previously described int genes, including those of the serotype B S. aureus phages L54a and phi 11. Nevertheless, all four S. aureus phages share an almost identical short sequence located immediately 5' to these distinct int genes, suggesting a common mechanism of int gene regulation. Upstream from these common sequences, the sequences of phi 13 and phi 42 are quite distinct from each other, and from the corresponding regions of phi 11 and L54a which encode the Xis proteins that are required with Int to mediate site-specific excision of the latter phages. Surprisingly, phi 13 and phi 42 sequences encompassing the attP sites and int genes, but lacking either an adjacent or more distant phage excision protein gene, were sufficient to mediate site-specific excision of integrated phage DNA sequences.

Amino Acid Sequence↗

PubMed1995

Investigation of the control of coronavirus subgenomic mRNA transcription by using T7-generated negative-sense RNA transcripts.

The subgenomic mRNAs of the coronavirus transmissible gastroenteritis virus (TGEV) are not produced in equimolar amounts. We have developed a reporter gene system to investigate the control of this differential subgenomic mRNA synthesis. Transcription of mRNAs by the TGEV polymerase was obtained from negative-sense RNA templates generated in situ from DNA containing a T7 promoter. A series of gene cassettes was produced; these cassettes comprised the reporter chloramphenicol acetyltransferase (CAT) gene downstream of transcription-associated sequences (TASs) (also referred to as intergenic sequences and promoters) believed to be involved in the synthesis of TGEV subgenomic mRNAs 6 and 7. The gene cassettes were designed so that negative-sense RNA copies of the CAT gene with sequences complementary to the TGEV TASs, or modified versions, at the 3' end would be synthesized in situ by T7 RNA polymerase. Using this system, we have demonstrated that CAT was expressed from mRNAs derived from the T7-generated negative-sense RNA transcripts only in TGEV-infected cells and only from transcripts possessing a TGEV negative-sense TAS. Analysis of the CAT mRNAs showed the presence of the TGEV leader RNA sequence at the 5' end, in keeping with observations that all coronavirus mRNAs have a 5' leader sequence corresponding to the 5' end of the genomic RNA. Our results indicated that the CAT mRNAs were transcribed from the in situ-synthesized negative-sense RNA templates without the requirement of TGEV genomic 5' or 3' sequences on the T7-generated negative-sense transcripts (3'-TAS-CAT-5'). Modification of the TGEV TASs indicated (i) that the degree of potential base pairing between the 3' end of the leader RNA and the TGEV negative-sense TAS was not the sole determinant of the amount of subgenomic mRNA transcribed and (ii) that other factors, including nucleotides flanking the TAS, are involved in the regulation of transcription of TGEV subgenomic mRNAs.

Animals↗

PubMed1995

Cervical Cancer: Screening and Prevention of Invasive Disease.

Cancer of the cervix is one of the leading causes of cancer-related deaths in women in the United States and accounts for more cancer deaths than any other cancer in third-world countries. Various screening procedures have been developed, but many issues need to be resolved for cervical cancer screening to be effective. Large segments of the population who do not undergo regular screening account for most of the patients with invasive cancers in the United States and worldwide. Allocation of resources and widespread educational programs for these target populations are needed to promote adequate cytologic screening programs and to reduce the death rate from squamous carcinoma of the cervix.

Journal Article↗

PubMed1995

Ileus following gynecologic surgery: management with water-soluble hyperosmolar radiocontrast material.

Postoperative ileus following gynecologic surgery can prolong hospitalization and may predispose patients to mechanical obstruction. Our objective was to study the safety and efficacy of a water-soluble, hyperosmolar, radiocontrast material in the management of postoperative ileus in patients having gynecologic surgery. Of 115 cases, 57 were studied prospectively and received water-soluble radio-opaque contrast material via a nasogastric tube if bowel function had not returned by the third day. Fifty-eight well-matched control cases were managed without this material and received a suppository on the third day. The contrast material was well tolerated. Return of bowel function, day of oral intake, subsequent postoperative recovery, and duration of hospital stay were similar in the two groups. Water-soluble, hyperosmolar, radio-opaque contrast material given on the third postoperative day was safe, but of no apparent clinical benefit in resolving ileus following gynecologic surgery.

Appendectomy↗

PubMed1994

Basal cell carcinoma of the vulva with groin node metastasis.

There have been five previous well-documented cases of metastatic vulvar basal cell cancer in the literature. We now present the sixth case-an 86-year-old patient with vulvar basal cell cancer metastatic to an ipsilateral groin node. She was treated with radical vulvectomy and bilateral inguinofemoral lymphadenectomy and remains free of disease 1 year later.

Aged↗

PubMed1994

Gastrostomy tubes after gynecologic oncologic surgery.

In order to prevent the complications of long-term nasogastric suctioning and increase patient comfort, we have been using gastrostomy tubes (G-tubes) in gynecologic oncology patients who are deemed to be at risk for protracted postoperative bowel dysfunction. This study describes our patient selection criteria and evaluates the results with 35 MIC (Medical Innovation Corporation, Milpitas, CA) gastrostomy tubes inserted between September 1, 1992 and April 30, 1993. The procedure is technically easy and adds approximately 10 min to operating time. The tubes were well tolerated by the patients over periods ranging from 5 to 135 days. All tubes were used for postoperative gastric drainage and in addition, eight tubes were used for short-term enteral feeding. One patient with short bowel syndrome continued enteral nutritional supplementation at home. Twenty patients were discharged with their G-tubes in situ. Five of these patients required continuous gastric drainage because of obstruction of gastric emptying or small bowel by advanced tumor, and four of them were taking full liquids orally prior to discharge from the hospital. Gastrostomy tubes are convenient adjuncts to postoperative care of the gynecologic oncology patient and afford palliation with few complications to patients dying with bowel obstruction.

Aged↗

PubMed1994

Pudendal thigh fasciocutaneous flaps for vaginal reconstruction in gynecologic oncology.

The pudendal thigh is a sensate fasciocutaneous flap supplied by the posterior labial artery. We report on the results of pudendal thigh flaps used for vaginal reconstruction in eight patients at the time of pelvic exenteration (6) and radical vaginectomy (2). Patients were interviewed and results were assessed 5 to 19 months after surgery. The flaps were raised in the thigh creases just lateral to the hair bearing area of the labia majora and included skin, subcutaneous tissues, deep fascia of the thigh, and the epimysium of the adductor muscles. Flap sizes varied from 9 x 4 cm to 15 x 6 cm. Bilateral flaps were used in seven patients. The flaps were technically easy to perform. Partial (apical) flap necrosis occurred in four patients. One patient developed complete necrosis of bilateral flaps, followed by an enterovaginal fistula. One patient whose flaps did not necrose developed a rectovaginal fistula at the site of rectal reanastomosis. The functional results are disappointing. The only patient having successful vaginal intercourse had a unilateral flap reconstruction following lower vaginectomy in a nonirradiated pelvis. No patient with bilateral flaps or prior pelvic irradiation has had successful coitus. Other long-term sequelae include vulvar pain (2), chronic vaginal discharge (2), hair growth (4), and protrusion of the flaps (2). These vulvovaginal symptoms discourage patients and their partners from genital contact. Breaching the integrity of the vulva to construct a neovagina that is likely to be unsuitable for sexual intercourse may deprive women of their only potential for normal genital sexual responsiveness. Techniques of vaginoplasty require continued assessment.

Adult↗

PubMed1994

Colorectal anastomosis on a gynecologic oncology service.

This is an evaluation of our experience with colorectal reanastomosis on a gynecologic oncology service. A retrospective review was carried out on all patients who underwent colorectal resection and reanastomosis on the gynecologic oncology service from October 1, 1987 to September 30, 1992. Thirty-nine procedures were performed: Nine patients underwent sigmoidectomy alone, 20 also underwent cytoreduction, and 10 also underwent exenteration. Thirty-eight percent of the patients had undergone prior radiotherapy. The level of anastomosis above the anal verge was 3-5 cm in 9 patients, 6-9 cm in 20 patients, and 10-14 cm in 10 patients. Sixteen had a protective colostomy which included 13 of the 15 patients with prior radiotherapy. Thirteen of the protective colostomies were taken down, although three of these required a second permanent colostomy. Three other patients required colostomy at a later date, one of whom developed a rectovaginal fistula 10 days following exenteration for postradiation recurrent carcinoma of the cervix. A total of 30 of the 37 evaluable patients (81%) had an ultimately functional colorectal reanastomosis. Problems related to colorectal function included stricture (4), fistula (4), chronic diarrhea (3), tenesmus (1), and fecal incontinence (1). Colorectal anastomosis is a worthwhile endeavor in selected patients with gynecologic cancer.

Adult↗

PubMed1994

Artificial Dura Film for femoral vessel coverage after inguinofemoral lymphadenectomy.

Eleven patients undergoing inguinofemoral lymphadenectomy for carcinoma of the vulva had the femoral vessels covered with Dura Film (Codman, Randolph, MA); a total of 21 groins were explored. The Dura Film was sutured to the inguinal ligament, sartorius muscle fascia, and adductor longus fascia. Nine of the 21 groins became infected with 3 of these breaking down; each of these 3 required removal of the Dura Film to achieve satisfactory healing. One patient developed a unilateral inflammatory groin mass requiring surgical removal of the Dura Film. One patient developed a chronic draining sinus that required surgical intervention. Seven groins developed lymphocysts. The morbidity was high with 9 of the 11 patients experiencing complications. Coverage of the femoral vessels with Dura Film after inguinofemoral lymphadenectomy is not an effective alternative to human dura mater or sartorius muscle transplant.

Aged↗

PubMed1994

Characterization of a replicating and packaged defective RNA of avian coronavirus infectious bronchitis virus.

The Beaudette strain of IBV was passaged 16 times in chick kidney cells. Total cellular RNA was analyzed by Northern hybridization and was probed with 32P-labeled cDNA probes corresponding to the first 2 kb of the 5' end of the genome, but excluding the leader, and to the last 1.8 kb of the 3' end of the genome. A new, defective IBV RNA species (CD-91) was detected at passage 6. The defective RNA, present in total cell extract RNA and in oligo-(dT)30-selected RNA from passage 15, was amplified by the reverse transcription-polymerase chain reaction (RT-PCR) to give four fragments. The oligonucleotides used were selected such that CD-91 RNA, but not the genomic RNA, would be amplified. Cloning and sequencing of the PCR products showed that CD-91 comprises 9.1 kb and has three regions of the genome. It contains 1133 nucleotides from the 5' end of the genome, 6322 from gene 1b corresponding to position 12,423 to 18,744 in the IBV genome, and 1626 from the 3' end of the genome. At position 749 one nucleotide, an adenine residue, was absent from CD-91 RNA. By Northern hybridization CD-91 RNA was detected in virions in higher amounts than the subgenomic mRNAs.

Base Sequence↗