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Biomedical subjects

D Coplen

Publications and source records attributed to D Coplen.

5 recordsLinked to original sources
PubMed2000

Congenital short colon with imperforate anus (pouch colon). Report of a case.

We report a case of a persistent cloaca and pseudoexstrophy associated with congenital pouch colon in a native-born American female child. This unusual anomaly occurs in two clinical settings. It has been reported in India as an isolated anomaly occurring primarily in males. Pouch colon also occurs in female patients with pseudoexstrophy or closed cloacal exstrophy. The typical anatomic features of this anomaly are discussed.

Abnormalities, Multiple↗
PubMed1995

Buccal mucosal urethral replacement.

Graft substances, such as skin and bladder mucosa, have been previously used for urethral replacement when local epithelial tissue was not available. However, these substances have been associated with meatal prolapse, stricture and fistula formation. We have used buccal mucosa as a tissue for urethral substitution in these situations during the last 8 years. We review our clinical experience in 18 urethral reconstructions performed for urethral replacement in 4 cases of exstrophy/epispadias, 12 complex hypospadias repairs and 2 cases of complex bulbar urethral strictures. There have been 5 cases of meatal stenosis (2 requiring operative revision) but none of meatal eversion. There has also been 1 urethrocutaneous fistula and 1 mid graft stricture. Mean followup was 27 months and minimum followup was 6 months. Histological examination of the buccal mucosal graft compared to grafts of skin showed that the full thickness of the dermis or lamina propria is thinnest while the native vascular supply is greatest in the buccal mucosa. These 2 factors are associated with improved graft take and may explain the encouraging clinical results.

Cheek↗
PubMed1994

Comparative studies on the ontogeny and autonomic responses of the fetal calf bladder at different stages of development: involvement of nitric oxide on field stimulated relaxation.

This initial study correlates the passive length-tension relationship, contractile and relaxant responses to field stimulation and contractile responses to specific autonomic agonists and antagonists with gestational age. Fetal bovine bladders were separated into three groups based on the head-rump length (FL): 30 to 45 cm. (early gestation), 50 to 65 cm. (middle gestation) and 70 to 85 cm. (late gestation). Each bladder was separated into upper and lower bladder segments; longitudinal strips of smooth muscle were isolated and placed in individual muscle baths. Passive length-tension studies demonstrated that compliance was greatest in the bladder of late gestation and lowest in the bladder of early gestation period. Field stimulation (FS) elicited frequency-dependent contractile responses in all strips. In the upper bladder, the maximal response and maximal rate of tension generation to FS was lowest in the youngest fetuses and increased in proportion to the gestational age. In the lower bladders, there were no gestational age-related differences in the maximal response or maximal rate of tension generation in response to field stimulation. The maximal response of the upper bladder to bethanechol increased significantly from the youngest gestational age to mid-gestation, with no further changes between mid- and late gestation. The maximal response to field stimulation and bethanechol were equal between upper and lower bladder segments for the youngest gestational bladders, whereas for the oldest gestational ages, the maximal response of the upper bladder to FS and bethanechol were significantly greater than the responses of the lower bladder. In the presence of maximal precontraction with bethanechol, FS induced a rapid and marked decrease in tension. The magnitude of the relaxation was substantially greater for the strips of lower bladder than for the strips of upper bladder at late gestation. In lower bladders, the magnitude of the field stimulated relaxation was greater in the strips from the older fetuses than in the strips from younger fetuses. In all strips, field stimulated relaxations were completely inhibited by pretreatment with L-NAME (an inhibitor of nitric oxide synthesis), indicating that the FS-induced relaxation was due to nitric oxide. In addition to nitric oxide-induced relaxation, beta adrenergic stimulation also induced a significant relaxation of the isolated strips. In summary, these data suggest that, in the tubular shaped fetal bovine bladder, there were distinct differences in the autonomic responses between the upper bladder segment and the lower bladder segment in the late gestation period.

Adenosine Triphosphate↗
PubMed1993

Distribution and function of the adrenergic and cholinergic receptors in the fetal calf bladder during mid-gestational age.

Previous studies on the developing fetal bovine bladder demonstrate that compliance is low during early stages of fetal development and increases with fetal age. In addition, the pharmacological response of isolated fetal bovine bladder smooth muscle strips to field stimulation and bethanechol increased in proportion with the gestational age. In the adult bladder (rabbit), the contractile response to autonomic receptor stimulation and the autonomic receptor density showed a parallel gradation in the the bladder between bladder dome and the urethra. The present studies were designed to determine the distribution of the cholinergic and adrenergic receptors in the urinary bladder of the fetal calf at mid-gestational age, and to correlate the receptor density with the magnitude of the response to receptor stimulation. Each bladder body was separated into upper, middle, and lower segments. For the functional studies, circular and longitudinal strips were cut from each bladder segment and stimulated with field stimulation (FS), bethanechol, methoxamine, isoproterenol, and KCl. Autonomic receptor assays were performed using 3H-QNB (muscarinic cholinergic), 3H-DHE (alpha adrenergic), and 3H-DHA (beta adrenergic) as ligands. In general, there were no significant differences in receptor density among the three bladder segments. However, the density of muscarinic receptors was significantly greater than the density of alpha- or beta-adrenergic receptors for all bladder segments. The receptor densities correlated very well with the functional response of isolated bladder strips to the specific autonomic agonists. The contractile response of isolated bladder strips to the specific autonomic agonists. The contractile responses of the strips to FS, bethanechol, and methoxamine were not significantly different among the three different bladder segments.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗