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Biomedical subjects

Darcie A Kiddoo

Publications and source records attributed to Darcie A Kiddoo.

8 recordsLinked to original sources

Structural and functional characterization of bladder smooth muscle in fetal rats with retinoic acid-induced myelomeningocele.

Myelomeningocele (MMC) is the most common cause of neurogenic bladder dysfunction (NBD). We recently developed a novel retinoic acid (RA)-induced MMC model in fetal rats. The objective of this study was to use this model to assess functional and structural characteristics of the detrusor muscle in MMC-associated NBD. Time-dated pregnant Sprague-Dawley rats were gavage fed 60 mg/kg RA dissolved in olive oil or olive oil alone [embryonic day 10 (E10)]. Bladder specimens from olive oil-exposed fetuses (OIL; n = 71), MMC (n = 79), and RA-exposed-no MMC (RA, n = 62) were randomly assigned for functional and histopathological evaluation and protein analysis. Contractility responses to field and agonist-mediated stimulation (KCl and bethanecol) were analyzed. The expression patterns of alpha-smooth muscle actin, myosin, desmin, vimentin, and collagen III and I were analyzed by immunohistochemistry and Western blotting. Spatial and temporal distribution of nerve fibers within the detrusor muscle was monitored by neurotubulin-beta-III throughout gestation. Neither OIL, MMC, nor RA detrusor responded to field stimulation. MMC bladder strips showed a significant decrease in contractility after KCl and bethanechol stimulation compared with OIL and RA bladders. Bladder detrusor morphology and expression patterns of smooth muscle markers were similar between groups. Detrusor muscles in OIL and RA fetuses were densely innervated, possessing abundant intramural ganglia and nerve trunks that branch to supply smooth muscle bundles. In MMC bladders, neurotubulin-beta-III-positive nerve fibers were markedly decreased with advancing gestational age and were almost completely absent at term (E22). We conclude that the biomechanical properties of fetal rat MMC bladders are analogous to that seen in humans with MMC-associated NBD. Decreased nerve density indicates loss of peripheral neural innervation throughout gestation. The early observation of decreased innervation and decreased contractility in the absence of morphologic abnormalities in muscle structure or extracellular matrix supports a pathophysiological hypothesis that denervation is the primary insult preceding the observed alterations in bladder muscle structure and function.

Animals↗

Impact of state of arousal and stress neuropeptides on urodynamic function in freely moving rats.

Corticotropin-releasing factor (CRF) is a neurotransmitter in Barrington's nucleus neurons. These neurons can coregulate parasympathetic tone to the bladder (to modulate micturition) and brain noradrenergic activity (to affect arousal). To identify the role of CRF in the regulation of micturition, the effects of CRF agonists and antagonists on urodynamics in the unanesthetized rat were characterized. Rats were implanted with bladder and intrathecal or intraperitoneal catheters under isoflurane anesthesia. Cystometry was performed in the unanesthetized, unrestrained state at least 24 h later. In some cases, cortical electroencephalographic activity (EEG) was recorded simultaneously to assess arousal state. During cystometry, the state of arousal often shifted between waking and sleeping and urodynamic function changed depending on the state. Micturition threshold, bladder capacity, and micturition volume were all increased during sleep. The CRF1/CRF2 receptor agonists CRF and urocortin 2 increased bladder capacity and micturition volume in awake but not in sleeping rats. Conversely, the CRF1 receptor antagonists antalarmin and NBI-30775 increased urinary frequency and decreased bladder capacity in awake rats. The present results demonstrate a profound effect of the state of arousal on urodynamic function and suggest that simultaneous monitoring of EEG and cystometry may provide a useful model for studying nocturnal enuresis and other urinary disorders. In addition, the results provide evidence for an inhibitory influence of CRF in the spinal pathway on micturition. Targeting the CRF system in the spinal cord may provide a novel approach for treating urinary disorders.

Animals↗

Urethral dilation as treatment for neurogenic bladder.

PURPOSE: We documented the change in bladder physiology and clinical outcomes after urethral dilation for managing neurogenic bladder. MATERIALS AND METHODS: Female patients with neurogenic bladder were identified who underwent urethral dilation due to failure to empty at low pressure or upper tract changes. Urethral dilation was performed using curved sounds to 36Fr (range 18Fr to 36Fr). Clinical charts were reviewed to document urodynamics, infection rates, symptomatology, vesicoureteral reflux and upper tract dilatation before and after dilation. RESULTS: A total of 19 children underwent urethral dilation a mean of 2 times. Mean age at first dilation was 19.3 months. Mean followup was 34.9 months. The indication for dilation was high detrusor leak point pressure in 16 children. The remaining children had recurrent infections (1), poor compliance (1) and bladder spasms (1). Clinical manifestations of increased detrusor leak point pressure in 16 children were vesicoureteral reflux in 11, upper tract dilatation in 9 and recurrent infections in 3. Long-standing improvement occurred in 12 of 16 patients with increased detrusor leak point pressure, in 0 of 1 with infection, in 0 of 1 with poor compliance and in 1 of 1 with bladder spasms. Overall improvement was noted in 13 of 19 cases (68%). Vesicoureteral reflux was identified in 14 of 19 patients. Improvement was seen in 6 of 14 cases, including complete resolution in 5 and improvement in 1. Hydronephrosis was seen in 11 of 19 patients with improvement in 7, including resolution in 1 and improvement in 6. Only 6 children required further surgical intervention, that is vesicostomy in 2 and reimplantation in 4. CONCLUSIONS: Urethral dilation is effective for lowering detrusor leak point pressure in children with neurogenic bladder and for improving upper tract dilatation and vesicoureteral reflux. This procedure may prevent the need for more complicated surgical intervention. It should be investigated further in well designed, prospective studies.

Child, Preschool↗

Diagnosis and management of pediatric urinary tract infections.

Urinary tract infection (UTI) is among the most commonly diagnosed bacterial infections of childhood. Although frequently encountered and well researched, diagnosis and management of UTI continue to be a controversial issue with many challenges for the clinician. Prevalence studies have shown that UTI may often be missed on history and physical examination, and the decision to screen for UTI must balance the risk for missed infections with the cost and inconvenience of testing. Interpretation of rapid diagnostic tests and culture is complicated by issues of contamination, false test results, and asymptomatic colonization of the urinary tract with nonpathogenic bacteria. The appropriate treatment of UTI has been controversial and has become more complex with the emergence of resistance to commonly used antibiotics. Finally, the anatomic evaluation and long-term management of a child after a UTI have been based on limited evidence, and newer studies question some of the tenets of prior recommendations. The goal of this review is to provide an up-to-date summary of the literature with particular attention to practical questions about diagnosis and management for the clinician.

Anti-Bacterial Agents↗

Initial management of complex urological disorders: bladder exstrophy.

Bladder exstrophy is a rare condition associated with lifelong issues including infection,renal insufficiency, incontinence, and fertility. Despite its seriousness, many affected children lead normal lives. With new operative techniques, children require fewer surgeries and have more hope for continence. With close follow-up, no child should develop renal insufficiency. Families should be reassured that a normal life and parenthood with normal sexual function are possible.

Animals↗

A population based assessment of complications following outpatient hydrocelectomy and spermatocelectomy.

PURPOSE: We determine the incidence of complications following outpatient scrotal surgery for the treatment of hydroceles and spermatoceles. MATERIALS AND METHODS: A retrospective study of all patients undergoing hydrocelectomy or spermatocelectomy between April 1, 1997 and March 31, 1999 at 1 institution was performed. The hospital and office charts were reviewed, and postoperative complications (infection, persistent swelling, chronic pain) were recorded. The type of preoperative antiseptic preparation (iodine based versus chlorhexidine) and the presence or absence of surgical drains were also recorded. RESULTS: A total of 161 patients were included in the study with an average age of 53.7 years. The overall complication rate was 19.2%. Infection/scrotal abscess formation occurred in 9.3% of patients, persistent swelling (treatment failure) in 9.3% and chronic pain in 0.6%. There was no significant difference in the complication rate when the preoperative preparations and the presence or absence of surgical drains were compared. CONCLUSIONS: The most common complications following scrotal surgery for hydroceles and spermatoceles are persistent scrotal swelling, inflammation and postoperative infection. Further prospective investigation is required to study factors such as the use of drains, preoperative and/or perioperative antibiotics and the type of surgical preparations, which may have a role in complication rates.

Adolescent↗

Unilateral nephrectomy as palliative therapy in an infant with autosomal recessive polycystic kidney disease.

Prenatal diagnosis of autosomal recessive polycystic kidney disease (ARPKD) implies a dire prognosis. Neonates affected by the more severe variants of ARPKD suffer respiratory failure caused by massive kidneys that restrict diaphragmatic expansion and result in pulmonary hypoplasia. Afflicted infants who survive the neonatal period and gain adequate respiratory function may subsequently suffer from an inability to tolerate enteral nutrition due to abdominal compression from the massive kidney and the systemic effects of renal compromise. Palliative unilateral or bilateral nephrectomy may be considered in rare instances to facilitate pulmonary expansion and gastrointestinal function. We report on an infant with severe ARPKD who was able to tolerate enteral nutrition only after left nephrectomy.

Humans↗