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Biomedical subjects

D Cavanagh

Publications and source records attributed to D Cavanagh.

At least 19 recordsLinked to original sources

Experimental evidence of recombination in coronavirus infectious bronchitis virus.

Embryonated eggs were coinfected with two strains of the coronavirus avian infectious bronchitis virus (IBV), IBV-Beaudette and IBV-M41, to investigate whether recombination between the two strains would occur. Virions were isolated from the allantoic fluid of the coinfected eggs and putative hybrid RNAs were detected by polymerase chain reaction (PCR), using strain-specific oligonucleotides. PCR products, of the expected sizes, were obtained as predicted from potential recombination events between the nucleoprotein (N) gene and the 3'-untranslated region of the two IBV genomes. Sequencing confirmed that they corresponded to hybrid RNAs. Virus produced as a result of the mixed infection was treated with an M41-specific neutralizing monoclonal antibody and passaged in Vero cells, in which IBV-Beaudette, but not IBV-M41, replicated. Hybrid RNA was still detectable after three serial passages. Since no IBV-M41 was detectable this confirmed that infectious recombinant genomes had been produced in the embryonated eggs. These findings not only support the circumstantial evidence, from sequencing studies of IBV field strains, that recombination occurs during replication of IBV and contributes to the diversity of IBV, but also show that coronavirus RNA recombination is not limited to mouse hepatitis virus.

Animals

A management scheme for postoperative groin lymphocysts.

During 1993, four persistent groin lymphocysts were diagnosed following inguinal lymphadenectomy for the management of gynecologic cancer. All four were successfully managed by a scheme involving active drainage combined with compression. Patient details and specifics of the suggested management scheme are outlined in the text.

Aged

Interleukin-12-mediated tumoricidal activity of patient lymphocytes in an autologous in vitro ovarian cancer assay system.

This study was designed to examine if interleukin-12 (IL-12) can induce cytolytic function of lymphocytes from ovarian cancer patients against either an ovarian cancer cell line or their own autologous tumor cells. Lymphocytes were obtained from the peripheral blood or ascites of ovarian cancer patients and activated with IL-12 alone or concomitantly with interleukin 2 (IL-2) for 2 to 3 days. Activation of lymphocytes and assessment of tumoricidal function by a chromium release assay were performed directly in a standard control medium (RPMI 1640 containing 2 mM glutamine, 100 micrograms/ml streptomycin, 100 units penicillin, 5% heat-inactivated human AB serum, and 5 mM 4-(2-hydroxyethyl)-1-piperazinesulfonic acid) and in 50% ascitic fluid (50% by volume filter-sterilized ascites with 50% of the above-mentioned control medium). Target cells were added directly into the medium in which the lymphocytes were activated in order to more closely mimic in vivo conditions. Lymphocytes, activated by IL-12 in 50% ascitic fluid, were able to lyse autologous tumor cells in 3 of 6 assays and were able to lyse SKOV3 cells (an ovarian cancer cell line) in 5 of 7 assays. The results were not significantly different in the control medium. When both IL-2 and IL-12 were used to activate lymphocytes in 50% ascitic fluid, significant cytotoxicity was generated in 6 of 6 autologous assays and in all 7 patient assays using SKOV3 as a target (P < 0.05). Synergy between the two cytokines was seen in all 13 patient assays in ascitic medium compared to only 5 of 13 assays in control medium. Additionally, when lymphocytes were stimulated with both IL-2 and IL-12, significantly greater cytotoxicity was seen in the ascitic fluid medium compared to the control medium in 13 of 14 assays (P < 0.05). No significant tumoricidal activity was seen by lymphocytes maintained in either medium without the addition of IL-2 or IL-12. Ascitic fluid consistently potentiates the synergy between IL-2 and IL-12 in generating cytotoxicity against ovarian cancer cells but does not increase cytotoxicity induced by IL-12 alone. IL-12 by itself activates tumoricidal activity of lymphocytes in ascitic fluid; however, the addition of IL-2 increases the degree and consistency of this effect. These data support the possibility that IL-12 may warrant further investigation as a potential therapeutic agent in the treatment of advanced ovarian cancer.

Ascitic Fluid

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

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

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

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

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

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

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

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

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

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

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

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

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