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Biomedical subjects

B E Davis

Publications and source records attributed to B E Davis.

At least 37 records · Page 2Linked to original sources
PubMed1995

Two [7.3.1]azabicyclo-z-3-ene-1,5-diyne analogues of dynemicin A.

The crystal structures of methyl 6-methoxy-17-oxo-2-azatricyclo[7.7.1.0(3,8)]heptadeca-3(8),4 ,6,13-tetraene- 11,15-diyne-2-carboxylate ethyl acetate solvate, (1), 2C19H15NO4.0.5C4H8O2, and tricyclo[3.3.1.1(3,7)]decyl 6-methoxy-17-oxo-2-azatricyclo[7.7.1.0(3,8)]heptadeca-3(8),4 ,6,13-tetraene- 11,15-diyne-2-carboxylate ethyl acetate solvate, (2), C28H27NO4.0.5C4H8O2, are reported. For compound (1), two crystallographically independent molecules are observed. Interestingly, for both compounds (1) and (2), a molecule of ethyl acetate is found in the crystal lattice disordered about an inversion center. The azabicyclo[7.3.1]enediyne core appears to be fairly rigid. Only minor differences are observed in the ring conformation between the two independent molecules in (1) and between compounds (1) and (2) themselves. The conformation is also similar to that found in deoxydynemicin A [Shiomi, Iinuma, Naganawa, Hamada, Hattori, Nakamura, Takeuchi & Iitaka (1990). J. Antibiot. 43, 1000-1005] and triacetyldynemicin A [Konishi, Ohkuma, Tsuno, Oki, Van Duyne & Clardy (1990). J. Am. Chem. Soc. 112, 3715-3716]. The transannular diyne distance (C3...C8) averages 3.428 (2) A for compound (1) and is 3.403 (3) A for compound (2).

Anthraquinones↗
PubMed1994

A novel dioxabicyclo[3.3.1]nonane, a key intermediate in the synthesis of erythronolide B seco-acid.

In the title compound, (1R,4S,5R,6R,8R)-1-ethyl-4,6,8-trimethyl-2,9-dioxabicyclo[3.3.1]++ +nonan-6-yl 1-imidazolecarboxylate, C16H24N2O4, the 2,9-dioxabicyclo[3.3.1]nonane ring system assumes a double-chair conformation. Bond angles around the ring are enlarged compared to normal tetrahedral values to alleviate some of the overcrowding which results from close intramolecular H...H and C...C contacts. The N-imidazolylcarbonyloxy group is nearly planar with dihedral angles of 5.2 (2) and 6.0 (2) degrees between the imidazole and carbonyl groups for molecules 1 and 2, respectively.

Bridged Bicyclo Compounds↗
PubMed1994

The management of patients with nonseminomatous germ cell tumors of the testis with serologic disease only after orchiectomy.

Management of patients with nonseminomatous germ cell tumors of the testis who have persistently elevated serum tumor marker levels (alpha-fetoprotein and/or human chorionic gonadotropin) following orchiectomy and no clinical evidence of disease is controversial. We reviewed our experience with 15 such patients at our cancer center between March 1977 and November 1991. Group 1 (11 patients) underwent initial retroperitoneal lymph node dissection and group 2 (4 patients) received primary chemotherapy. All group 1 patients required subsequent chemotherapy for retroperitoneal disease or persistent marker elevation, whereas only 1 of the 4 who received primary chemotherapy required later surgery. We conclude that tumor marker elevation in this setting is usually indicative of systemic tumor, which is best treated primarily by initial chemotherapy.

Adult↗
PubMed1993

Combined cholecystectomy and radical genitourinary cancer surgery.

We have routinely performed simultaneous cholecystectomy in patients with cholelithiasis undergoing selected radical genitourinary cancer surgery. A total of 31 patients have undergone cholecystectomy at the time of radical nephrectomy (25), radical cystectomy (5), and radical prostatectomy (1). Operative time was increased twenty-five to forty-five minutes. There was no significant increase in blood loss, postoperative total bilirubin, or number of complications. No complications were directly attributable to the cholecystectomy except for 1 patient who had prolonged drainage from a closed suction drain in the gallbladder fossa. We conclude that concomitant cholecystectomy at the time of radical genitourinary cancer surgery does not significantly increase morbidity and recommend that it be performed in the presence of cholelithiasis.

Adult↗
PubMed1993

Management of abdominal aortic aneurysm and invasive transitional cell carcinoma of bladder.

Between January 1980 and June 1990 we treated 21 patients with invasive carcinoma of the bladder and abdominal aortic aneurysm. Three distinct groups of patients were identified. Group 1 comprised 8 patients who were initially diagnosed with invasive bladder cancer and during cancer staging a concomitant abdominal aortic aneurysm was found. Group 2 consisted of 10 patients previously treated for invasive bladder cancer who had aneurysmal disease at a later date. Group 3 included 3 patients who underwent a previous aneurysm repair and subsequently had invasive carcinoma of the bladder. Total survival was 9 of 21 patients (43%) with a mean of 84 months of followup after initial diagnosis. This finding is comparable to long-term (greater than 5 years) survival in patients with invasive carcinoma of the bladder alone. In fact, none of the 21 patients studied experienced rupture of the aneurysm and/or died of aneurysmal disease. We found that patients with abdominal aortic aneurysm and invasive bladder cancer have a poor overall prognosis. Although aneurysm repair presents technical challenges, mortality is dependent upon the carcinoma and other vascular or medical diseases, and does not bear direct relationship to abdominal aortic aneurysm.

Aged↗
PubMed1993

Serum soluble interleukin 2 receptor levels in erythrodermic cutaneous T-cell lymphoma correlate with response to photopheresis-based treatment.

BACKGROUND: Cutaneous T-cell lymphoma (CTCL) comprises a spectrum of presentations, including erythroderma, pruritus, lymphadenopathy, and circulating atypical lymphocytes. Photopheresis is an extracorporeal treatment in which white blood cell concentrates are subjected to UV irradiation when the serum methoxypsoralen level is above 50 ng/mL. Of patients with CTCL, those with erythroderma have been most responsive to this therapy. In some conditions, including certain malignant hematologic neoplasms, serum soluble interleukin 2 receptor levels (SIL2R) correlate with disease activity. We sought to determine whether serum SIL2R levels correlated with disease activity in six erythrodermic patients with CTCL treated primarily with photopheresis. We measured SIL2R levels in five patients with stage III or greater erythrodermic CTCL and one with stage IIa CTCL. We compared SIL2R values with clinical course, skin scores, CD4/CD8 ratios, peripheral white blood cell counts, and Sézary cell counts, using Pearson correlation coefficients. OBSERVATIONS: The SIL2R levels correlated with clinical course and skin scores, even when controlled for other factors noted above. CONCLUSION: Data preliminarily suggest that serum SIL2R levels may be useful indicators of disease activity in erythrodermic CTCL patients treated with photopheresis.

Adult↗
PubMed1992

Structure of a chiral intermediate in the synthesis of (+)-19-epiajmalicine.

[2S*-(2 beta,3 alpha,6 alpha,12b beta)]-Methyl 3-acetyl-1,2,3,4,6,7,12,12b-octahydro-6-methoxycarbonyl-indolo+ ++[2,3-a] quinolizine-3-ethanoate, C22H26N2O5, M(r) = 398.46, orthorhombic, P2(1)2(1)2(1), a = 9.463 (2), b = 11.251 (3), c = 18.871 (6) A, V = 2009.2 (9) A3, Z = 4, Dx = 1.32 g cm-3 (178 K), lambda(Mo K alpha) = 0.7107 A, mu = 0.8762 cm-1, F(000) = 848, T = 178 K, R = 0.0536 for 1673 reflections [Fo > or = 6 sigma (Fo)]. Molecules are hydrogen bonded along the 2(1)-screw axis parallel to a. The hydrogen-bond geometric parameters for N12-H12...O19 (related by 0.5 + x, 1.5 - y, 1 - z) are N...O 2.986 (6), H...O 2.30 (5) A, N-H...O 161 (5) degrees. The C and D rings are trans fused with ring-junction torsion angles of -39.6 (5) and 63.8 (5) degrees for C12a-C12b-N5-C6 and C1-C12b-N5-C4, respectively. The conformation of the C ring is half chair with N5 and C6 -0.168 (4) and 0.552 (5) A, respectively, out of the plane defined by the remaining four atoms of the ring. The D ring is in the chair conformation.

Crystallization↗
PubMed1992

Structure of a tricyclic subunit of manzamine A.

(4a alpha,7a beta,10a beta)-2-Benzyl-1,2,3,4,4a,7,7a,8,9,10-decahydro-8,8- dimethylpyrrolo[2,3-i]isoquinolinium iodide, C20H29N2+.I-, M(r) = 424.37, monoclinic, P2(1)/n, a = 9.441 (4), b = 10.378 (4), c = 20.023 (9) A, beta = 91.56 (3) degrees, V = 1961 (1) A3, Z = 4, Dx = 1.44 g cm-3 (188 K), lambda(Mo K alpha) = 0.7107 A, mu = 16.16 cm-1, F(000) = 864, T = 188 K, R = 0.0288 for 3070 reflections [Fo greater than or equal to 4 sigma(Fo)]. The crystal structure determination was undertaken in order to establish the configuration around C10a. The rings of the isoquinoline group are trans, with the pyrrole moiety cis fused. The A ring is in the chair conformation, while the cyclohexene ring, B, is in the boat conformation owing to the cis fusion of the five-membered pyrrole ring. The pyrrole ring, C, assumes the half-chair conformation. The C-N bonds of the quaternary N atom, N8, are longer than those of the tertiary N atom, N2 [1.517 (2) for N8 and 1.463 (2) A for N2].

Carbazoles↗
PubMed1992

Structure of a protected C3-C10 subunit of erythromycin and its C8 epimer.

(1) (2S,3R,4R,6R)-3,4-O-Carbonyl-7,7-dimethylenedithio-2,4,6-trimet hylnonane-1,3,4-triol, C15H26O4S2, M(r) = 334.49, triclinic, P1, a = 6.460 (2), b = 8.917 (3), c = 15.616 (5) A, alpha = 83.60 (3), beta = 83.41 (2), gamma = 89.52 (2) degrees, V = 888.0 (5) A3, Z = 2, Dx = 1.25 g cm-3, mu = 2.980 cm-1, lambda (Mo K alpha) = 0.7107 A, F(000) = 360, T = 298 K, R = 0.0465 for 1832 reflections [Fo greater than or equal to 4 sigma (Fo)]. (2) (2S,3R,4R,6S)-3,4-O-Carbonyl-7,7-dimethylenedithio-2,4,6-trimet hylnonane-1,3,4-triol, C15H26O4S2, M(r) = 334.49, monoclinic, P21, a = 8.1849 (8), b = 8.9456 (14), c = 12.0258 (14) A, beta = 100.878 (8) degrees, V = 864.7 (2) A3, Z = 2, Dx = 1.28 g cm-3, mu = 3.060 cm-1, lambda (Mo K alpha) = 0.7107 A, F(000) = 360, T = 298 K, R = 0.0569 for 2001 reflections [Fo greater than or equal to 4 sigma (Fo)]. The two diastereomers differ in configuration at C6. For (1) there are two unique molecules in the unit cell. These two molecules differ in conformation by a rotation about the bond C7-C8. The molecules are hydrogen bonded into infinite chains along b. The hydroxyl O atom of molecule (2), O10', acts as both a donor and an acceptor in hydrogen-bonding interactions with the carbonyl O atom, O14, and the hydroxyl H atom, H10, of molecule (1).(ABSTRACT TRUNCATED AT 250 WORDS)

Erythromycin↗
PubMed1992

Management of preexisting inflatable penile prosthesis during radical retropubic prostatectomy.

A potentially difficult technical situation exists when a man with a functioning inflatable penile prosthesis elects radical prostatectomy as treatment for localized prostate cancer. Between February 1988 and June 1991 we encountered 8 men with a preexisting inflatable penile prosthesis who subsequently underwent radical retropubic prostatectomy. In 2 patients the reservoir portion of the prosthesis was in the perivesical space such that radical prostatectomy could be performed without difficulty. However, in 6 patients removal of the reservoir was necessary to complete the prostatectomy. In 3 of these 6 patients the reservoir was replaced at 3 to 6 months after radical prostatectomy and all 3 systems function well. The remaining 3 patients have not yet elected replacement of the reservoir. Only 1 patient had an infection and a complication attributable to the prosthesis. We believe that a preexisting inflatable penile prosthesis should not preclude successful radical retropubic prostatectomy, although temporary removal of the reservoir may be required.

Aged↗
PubMed1992

Initial experience with combined interferon-alpha 2B and carbon dioxide laser for the treatment of condylomata acuminata.

The incidence of condylomata acuminata, a common sexually transmitted disease caused by certain types of human papillomaviruses, is increasing rapidly and treatment regimens presently are not consistently effective. One of the more popular and effective modes of treatment has been laser therapy. Because of the relatively high recurrence rate of condylomata acuminata with laser treatment alone and because laser treatment in some patients with confluent acetowhite lesions would render cosmetically unacceptable results in the entire area were treated, we believed that it was reasonable to use intralesional pretreatment. We present our preliminary data on 14 consecutive patients with the clinical diagnosis of condylomata acuminata who were treated with the combination of carbon dioxide laser and intralesional interferon-alpha 2B. We found the treatment regimen to be effective in decreasing the recurrence rate compared to laser treatment alone and it was well tolerated with only transient side effects in a minority of patients. We are encouraged by our result and have recently begun a randomized double-blind prospective study to provide more conclusive information regarding this treatment combination.

Adolescent↗
PubMed1992

Simplified urinary diversion in patients with preexisting or imminent colostomy.

The indications for urinary and fecal diversion often mirror each other and at times overlap. Between 1980 and 1990 we encountered 14 patients with preexisting or newly diagnosed rectosigmoid disease who required diverting colostomy and urinary diversion. We describe a simple method for managing urinary diversion in these patients, which avoids a bowel anastomosis. The preexisting or newly created colostomy is used as the urinary stoma for a colon conduit, while a proximal colostomy is created for fecal diversion. This technique has proved to be beneficial and should be considered for high risk patients who require urinary and fecal diversion, and for whom an abbreviated operation would be desired.

Adult↗
PubMed1991

Structure of 18'-epivinblastine.

Methyl (3aR-[3a alpha,4 beta,5 beta,5a beta,9(3R*,5S*,7R*,9R*), 10bR,13a alpha])-4-(acetyloxy)-3a-ethyl-9-[5-ethyl-1,4,5,6,7,8,9, 10-octahydro-5-hydroxy-9-(methoxycarbonyl)-2H-3,7- methanoazacycloundecino[5,4-b]indol-9-yl]-3a,4,5,5a,6,11,12, 13a-octahydro-5-hydroxy-8-methoxy-6-methyl-1H-indolizino-[8,1-c,d] carbazole- 5-carboxylate methanol solvate, C46H58N4O9. 2CH3OH (1), Mr = 875.07, monoclinic, P2(1), a = 10.2759 (12), b = 22.353 (3), c = 10.4051 (12) A, beta = 106.502 (9) degrees, V = 2291.6 (5) A3, Z = 2, Dx = 1.27 g cm-3, Mo K alpha radiation, lambda = 0.7107 A, mu = 0.8397 cm-1, F(000) = 940, T = 198 K, R = 0.0470 for 2751 reflections, Fo greater than or equal to 4 sigma(Fo). The C ring of the vindoline moiety is in the boat conformation with the hydroxy group and the tertiary N in the bowsprit positions resulting in a fairly short intramolecular hydrogen-bonding interaction. The relevant parameters for O3--H3...N9 are O...N 2.651 (6), H...N 1.94 (5) A and O--H...N 147 (5) degrees. The D and E rings are in the sofa and envelope conformations, respectively. The piperidine ring of the catharanthine portion of the molecule assumes the chair conformation while the conformation of the azacyclononene ring is a boat-chair. An intramolecular hydrogen bond between the indolino NH of the catharanthine moiety and methoxy O (O25) of the vindoline moiety is also observed. The relevant parameters for N16'--H16'...O25 are N...O 2.827 (6), H...N2.14 (6) A and O--H...N 136 (5) degrees.

Molecular Conformation↗