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Biomedical subjects

M J Cunningham

Publications and source records attributed to M J Cunningham.

At least 19 recordsLinked to original sources
PubMed1995

Lateral sinus thrombosis associated with otitis media and mastoiditis in children.

Lateral sinus thrombosis (LST) is an infrequent complication of otitis media and mastoiditis in the antibiotic era. A recent case of LST in a 7-year-old boy, the third such case at our institutions in the past 5 years, prompted a review of the modern day English literature concerning LST in pediatric patients. Our goal was to highlight the clinical findings suggestive of LST in the antibiotic era as well as to analyze retrospectively the diagnostic and therapeutic modalities of greatest benefit based on the outcomes reported in the reviewed studies.

Anti-Bacterial Agents↗
PubMed1992

Apnea and the elongated uvula.

Four cases of respiratory distress and apnea associated with an elongated uvula are presented. In all cases, the uvula was found to intermittently fall onto the epiglottis and vocal cords. In all four patients, resection of the uvula led to resolution of all airway symptoms. It is hypothesized that the uvula, touching the vocal cords, caused intermittent laryngospasm and subsequent symptoms of cough, airway obstruction, and cyanosis. The anatomic reasons for such phenomenon are discussed.

Airway Obstruction↗
PubMed1992

Meningitis and midline facial deformity.

A baby with unilateral cleft lip, midline cleft palate and hypertelorism developed meningitis in the first 48 h of life. Examination of the nasopharynx showed a soft tissue mass, which was confirmed as a basal encephalocele by computed tomography. There was also congenital hydrocephalus and the corpus callosum was absent. Surgical treatment included repair of the anterior basal skull defect, repair of the lip and palate, and ventriculo-peritoneal shunt. There is currently evidence of developmental delay and right-sided visual impairment due to Morning Glory syndrome. This case demonstrates that basal encephalocele should be considered in any baby with midline facial deformity who develops meningitis.

Cleft Lip↗
PubMed1992

Orbital complications of acute sinusitis: comparison of computed tomography scan and surgical findings.

The accuracy of computed tomography (CT) in distinguishing an abscess from cellulitis in children who present with orbital manifestations of paranasal sinus infection remains in question. In this 10-year retrospective study, CT results are compared with surgical findings in 19 patients with orbital complications who underwent surgical exploration within 24 hours of their CT scans. Fifteen of the 19 CT scan interpretations indicated abscesses that were verified intraoperatively. Two patients had negative surgical explorations despite CT interpretations predicting abscesses. An abscess was also surgically documented in 1 of 2 patients whose preoperative scans indicated cellulitis alone. We conclude that the correlation between radiologic and operative findings in 16 of these 19 cases, although not absolute, does substantiate the use of CT scanning as a therapeutic guide in children presenting with orbital disease secondary to paranasal sinusitis.

Abscess↗
PubMed1992

The old and new of acute laryngotracheal infections.

Laryngotracheal infections in childhood frequently result in airway obstruction, the major symptom of which is stridor. The primary aims of management are to establish a diagnosis rapidly and to maintain or secure the child's airway. Medical treatment and airway stabilization measures vary for the three most prevalent laryngotracheal infections--supraglottitis, laryngotracheitis, and bacterial tracheitis--as well as for older and newer infectious airway entities.

Acute Disease↗
PubMed1991

Extended-field radiation therapy in early-stage cervical carcinoma: survival and complications.

Four hundred fifteen patients with early-stage cervical carcinoma were explored via a transperitoneal approach for radical hysterectomy at the Hospital of the University of Pennsylvania between January 1, 1960, and December 31, 1985. Twenty-four of these patients were found to have histologic documentation of para-aortic lymph node metastases. Twenty-one patients (88%) were treated primarily with extended-field radiotherapy. Forty-eight percent of these patients have survived greater than 5 years from diagnosis. Six patients have been followed more than 10 years after initial treatment. All six are alive although one patient has recurrent disease that was diagnosed at 164 months. Patients with adenocarcinoma or adenosquamous carcinoma had a survival significantly lower than that of those with squamous cell cancers (p = 0.022). Complications included one treatment-related death from multiple fistulas and sepsis, one vesicovaginal fistula, two enteric fistulas, and two small bowel obstructions. The major morbidity rate was 19%. Extended-field radiation is effective therapy for para-aortic nodal metastasis associated with early-stage squamous cell carcinomas of the cervix but carries a considerable morbidity rate. Other modalities such as combined chemotherapy and radiation may be necessary for adenocarcinoma.

Adenocarcinoma↗
PubMed1991

Preventing perioperative obstruction of tympanostomy tubes: a prospective trial of a simple method.

The intraluminal obstruction of tympanostomy tubes by hemorrhage incurred in the perioperative period is not a rare problem. The exact frequency, however, is unknown and methods of prevention have not been studied. We prospectively investigated a method of unilaterally coating one grommet with antibiotic ointment in 128 children undergoing bilateral tympanostomy tube placement; the contralateral tube was not treated. We established the incidence of intraluminal obstruction by blood in untreated grommets to be 4.7%. The incidence of hemorrhagic obstruction of the coated tubes was less (2.3%) but did not achieve statistical significance (P less than 0.20). The technique of antibiotic ointment application to the tympanostomy tube at the time of surgery was not sufficiently efficacious to justify routine use.

Acute Disease↗
PubMed1990

Diastolic function in left ventricular hypertrophy: clinical and experimental relationships.

The evaluation of patients with left ventricular hypertrophy and the clinical syndrome of congestive heart failure requires the ability to distinguish between the etiologies of abnormal systolic contractile function and abnormalities of diastolic relaxation and filling. In patients with left ventricular hypertrophy and congestive heart failure, predominant diastolic dysfunction should be suspected when elevation of left ventricular diastolic pressure is detected in the presence of normal diastolic chamber volume or dimensions and preserved systolic shortening. The mechanisms which account for diastolic dysfunction in the presence of cardiac hypertrophy are controversial and are likely to be multiple. These mechanisms may include changes in left ventricular geometry, per se, changes in the composition of the left ventricular wall (fibrosis or alteration in collagen), and dynamic factors which modulate diastolic force inactivation (loading conditions, cytosolic calcium handling, cyclic AMP availability). In addition, recent studies suggest that hypertrophied cardiac muscle may be particularly susceptible to develop diastolic dysfunction in response to the stress of hypoxia or ischaemia.

Cardiac Volume↗
PubMed1990

Influence of glucose and insulin on the exaggerated diastolic and systolic dysfunction of hypertrophied rat hearts during hypoxia.

Myocardial hypertrophy can result in increased sensitivity toward the development of mechanical dysfunction during hypoxia. Alterations in glycolytic metabolism may contribute to this. We studied the response to 15 minutes of hypoxia in hypertrophied (deoxycorticosterone-salt hypertension model) and nonhypertrophied rat hearts and examined the influence of a high glucose (27.5 mM) and insulin (100 mU/ml) concentration. In response to hypoxia in the presence of a normal glucose concentration (5.5 mM), left ventricular end-diastolic pressure was higher in hypertrophied than in nonhypertrophied hearts (65 +/- 6 vs. 44 +/- 4 mm Hg; p less than 0.05). Perfusion with high glucose and insulin blunted the rise in left ventricular end-diastolic pressure in both hypertrophied and nonhypertrophied hearts and abolished the difference in diastolic dysfunction between groups during hypoxia (26 +/- 2 vs. 32 +/- 4 mm Hg, respectively; p = NS). At end hypoxia in the presence of a normal glucose concentration, developed pressure was more depressed in hypertrophied than in nonhypertrophied hearts (11 +/- 1 vs. 18 +/- 1% of baseline, respectively; p less than 0.05). Perfusion with high glucose and insulin resulted in improved function in both groups during hypoxia such that a greater impairment of developed pressure was no longer present in the hypertrophied versus nonhypertrophied hearts (21 +/- 1 vs. 24 +/- 2% of baseline, respectively; p = NS). At the end of hypoxic perfusion in the presence of a normal glucose concentration, hypertrophied hearts were producing 38% less lactate than nonhypertrophied hearts. Perfusion with high glucose and insulin increased lactate production in both groups and equalized lactate production between groups. Thus, the greater deterioration in hemodynamic function in hypertrophied hearts compared with nonhypertrophied hearts during hypoxia is associated with lower lactate production. Both the exaggerated hemodynamic dysfunction and deficient lactate production can be ameliorated by perfusion with a high glucose concentration and insulin.

Animals↗
PubMed1990

Contribution of endothelial cells to calcium-dependent fluorescence transients in rabbit hearts loaded with indo 1.

In studies that attempt to measure intracellular calcium [( Ca2+]i) in the intact heart with the calcium indicator indo 1-AM, a fundamental assumption is that the signals report changes in myocyte [Ca2+]i. We studied isolated perfused rabbit hearts loaded with the calcium probe indo 1-AM and recorded surface fluorescence of the left ventricle during continuous excitation at 360 nm. In cells containing indo 1, an increase in [Ca2+]i is associated with an increase in fluorescence intensity at 400 nm, a decrease in intensity at 500 nm, and an increase in the 400:500 nm ratio. Beat-to-beat fluorescence transients were recorded from the surface of the heart coincident with contraction, indicating that a component of the fluorescence signals is derived from beating myocytes. To evaluate the potential contribution of endothelial cells, we compared the response to increases in [Ca2+]o or bradykinin (10(-5) M). In response to an increase of the [Ca2+] in the perfusate from 0.6 to 3.0 mM, left ventricular developed pressure and +dP/dt increased with a simultaneous increase in the [Ca2+]i-sensitive 400:500 nm ratio. Perfusion with the endothelial cell agonist bradykinin caused no change in left ventricular isovolumic peak systolic pressure or left ventricular dP/dt, whereas bradykinin evoked an immediate elevation in both the diastolic and systolic levels of the [Ca2+]i-sensitive 400:500 nm ratio. In additional experiments with indo 1-loaded isolated beating myocytes, superfusion with bradykinin had no effect on either the fluorescence [Ca2+]i transients or contractility. In contrast, superfusion of indo 1-loaded cultured endothelial cells with bradykinin caused the elevation of [Ca2+]i within seconds. Fluorescence microscopy of unstained frozen tissue sections from indo 1-loaded hearts also suggested the presence of more intense microvascular endothelial cell indo 1 fluorescence relative to that observed in myocytes. These experiments provide evidence that a component of [Ca2+]i-sensitive fluorescence of whole hearts loaded with indo 1 is contributed by nonmyocyte sources, including endothelial cells. These results also raise the caution that the abrupt rise of [Ca2+]i that has been observed during the initial phase of ischemia in whole hearts loaded with indo 1 may be partly derived from endothelial cells rather than myocytes.

Animals↗
PubMed1990

In vitro and in vivo genotoxicity of 1,3-butadiene and metabolites.

1,3-Butadiene and two major genotoxic metabolites 3,4-epoxybutene (EB) and 1,2:3,4-diepoxybutane (DEB) were used as model compounds to determine if genetic toxicity findings in animal and human cells can aid in extrapolating animal toxicity data to man. Sister chromatid exchange (SCE) and micronucleus induction results indicated 1,3-butadiene was genotoxic in the bone marrow of the mouse but not the rat. This paralleled the chronic bioassays which showed mice to be more susceptible than rats to 1,3-butadiene carcinogenicity. However, 1,3-butadiene did not induce unscheduled DNA synthesis (UDS) in the rat or mouse hepatocytes following in vivo exposure. Likewise, UDS in rat and mouse hepatocytes in vitro was not induced by EB or DEB. Salmonella typhimurium gene mutation (Ames) tests of 1,3-butadiene using strains TA1535, TA97, TA98, and TA100 and employing rat, mouse, and human liver S9 metabolic systems were barely 2-fold above background only in strain TA1535 at 30% 1,3-butadiene in air with induced and uninduced rat S9 and mouse S9 (uninduced). 1,3-Butadiene was negative in in vitro SCE studies in human whole blood lymphocytes cultures treated in the presence of rat, mouse, or human liver S9 metabolic activation. In general, 1,3-butadiene is genotoxic in vivo but is a weak in vitro genotoxin.

Animals↗
PubMed1989

Otologic manifestations of Langerhans' cell histiocytosis.

Eighteen of 62 children diagnosed with Langerhans' cell histiocytosis at the Children's Hospital of Pittsburgh (Pa) between 1970 and 1986 demonstrated ear and temporal bone involvement. In six children, such otologic disease was their sole presenting manifestation. Common signs and symptoms included aural discharge, postauricular swelling, and conductive hearing loss. The otologic findings in these children, if not investigated properly, could easily be attributed to acute or chronic infectious ear disease. Computed tomography with contrast enhancement proved to be particularly valuable as a diagnostic study because of its clear delineation of both osseous and soft-tissue temporal bone involvement. Computed tomographic findings could also be used to enhance local treatment by guiding surgical biopsy and curettage procedures or defining low-dose radiation therapy portals. Eleven of these 18 children with otologic Langerhans' cell histiocytosis additionally required chemotherapy due to the systemic nature of their disease.

Child↗