Biomedical subjects

L N Sutton

Publications and source records attributed to L N Sutton.

At least 91 records · Page 5Linked to original sources

PubMed1991

Distribution of bacteria in the operating room environment and its relation to ventricular shunt infections: a prospective study.

In order to study the distribution of bacteria in the operating room environment, cultures were obtained during 111 unselected shunt operations throughout a 10-month period. After routine skin preparation, bacteria were collected by placing Millipore filters on the patient's prepped skin underneath the drapes, on top of the drapes in the operative field, and/or on the sterile instrument table, and left in place for the duration of the case. In 48 patients, full-thickness skin biopsies taken at the initial incision were cultured in lieu of skin surface cultures. Perioperative cerebrospinal fluid cultures and subsequent shunt infections were monitored. Of the 288 environmental (skin and surfaces) cultures, 24 were positive (20 coagulase-negative Staphylococcus and 4 Staphylococcus aureus). Positive cultures were found in 15 of 111 drape cultures (13.5%), 7 of 77 instrument table cultures (9.1%), and 2 of 97 skin cultures (2.1%). Positive environmental cultures were not correlated with the surgeon, length of case, time of day, or type of shunt operation, but were more likely to occur in a room other than the designated neurosurgical operating room. There was a correlation between the occurrence of positive environmental cultures and positive cerebrospinal fluid cultures, although the organisms were not always the same. Coagulase-negative Staphylococcus was the most common organism isolated from all sites. We conclude that bacteria most often associated with shunt infections are airborne in the operating room, rather than originating from the patient's skin, and are distributed in the highest concentration near the surgical team.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Global cerebral ischemia in piglets under conditions of mild and deep hypothermia.

BACKGROUND AND PURPOSE: To investigate the effects of hypothermia on the rate of change and degree of recovery of brain adenosine triphosphate and phosphocreatine concentrations and intracellular pH, we have developed a model that allows phosphorus nuclear magnetic resonance spectroscopy of the intact piglet brain during circulatory arrest. METHODS: Three groups of piglets were studied. Three control animals underwent cardiopulmonary bypass at normothermia for 1 hour; five group 1 animals underwent bypass at a brain temperature of 15 degrees C, followed by a period of circulatory arrest such that adenosine triphosphate was absent for 21 minutes, followed by 1 hour of reperfusion; and five group 2 animals underwent bypass at a brain temperature of 37 degrees C, followed by a period of circulatory arrest such that adenosine triphosphate was absent for 21 minutes, followed by reperfusion for 1 hour. RESULTS: Control animals showed no significant metabolic effects of bypass. Group 1 animals showed a slower decay of the adenosine triphosphate and phosphocreatine concentrations than group 2 animals, consistent with a lower metabolic rate, and had a higher pH at the onset of ischemia. Recovery of the adenosine triphosphate concentration was significantly better in group 1 animals (95%) than in group 2 animals (30%) (p less than 0.02), and recovery of the phosphocreatine concentration was also better in group 1 animals (93%) than in group 2 animals (32%) (p less than 0.02). Intracellular pH recovered in group 1 animals, but not in group 2 animals. Regional biochemical assays of metabolites performed in the group 2 piglets and in five pilot piglets exposed to deep hypothermia generally confirmed the spectroscopic findings but demonstrated considerable regional variation, specially in the group 2 piglets' brains. CONCLUSIONS: We conclude that hypothermia exerts a protective effect on the piglet brain during global ischemia even after the adenosine triphosphate pool has been completely depleted.

Adenosine Diphosphate↗

PubMed1991

Torticollis in children.

Torticollis is a common clinical sign that is found in a variety of disorders. Childhood torticollis differs from the adult form in that congenital types are common and many frequently encountered disorders found in adults are unusual. Pediatric torticollis related to otolaryngologic conditions is reviewed, and three illustrative cases are presented.

Child↗

PubMed1991

Improved survival with the use of adjuvant chemotherapy in the treatment of medulloblastoma.

Between 1975 and 1989, 108 children with newly diagnosed medulloblastoma/primitive neuroectodermal tumor (MB/PNET) of the posterior fossa were treated at the authors' institution. The patients were managed uniformly, and treatment included aggressive surgical resections, postoperative staging evaluations for extent of disease, and craniospinal radiation therapy with a local boost. Beginning in 1983, children with MB/PNET were prospectively assigned to risk groups; those with "standard-risk" MB/PNET were treated with radiation therapy alone, while those in the "poor-risk" group received similar radiation therapy plus adjuvant chemotherapy with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), vincristine, and cisplatin. The 5-year actuarial disease-free survival rate for all patients treated between 1975 and 1982 was 68%, and 73% when patients who died within 2 weeks after operation were excluded. This survival rate was statistically better for patients treated after 1982 (82%) compared to those treated between 1975 and 1982 (49%) (p less than 0.004). There was no difference in disease-free survival rates over time for children with standard-risk factors; however, there was a significant difference in the 5-year survival rate for poor-risk patients treated prior to 1982 (35%) compared to those treated later (87%) (p less than 0.001). For the group as a whole, a younger age at diagnosis correlated with a poorer survival rate; however, this relationship between age and outcome was significant only for children treated before 1983 (p less than 0.001). These results demonstrated an encouraging survival rate for children with MB/PNET, especially those treated with aggressive surgical resection followed by both radiation therapy and chemotherapy. The results strongly suggest that chemotherapy has a role for some, and possibly all, children with MB/PNET.

Adolescent↗

PubMed1991

Fusiform dilatations of the carotid artery following radical surgery of childhood craniopharyngiomas.

Between 1982 and 1990, a series of 31 children with craniopharyngiomas underwent initial surgery at the Children's Hospital of Philadelphia with an attempt at total tumor removal. Nine (29%) of them were found to have fusiform dilatation of the supraclinoid carotid artery either at the time of surgery for recurrence (one patient) or on routine surveillance with enhanced computerized tomography 6 to 18 months postoperatively (eight patients). The finding of carotid enlargement was confirmed in seven cases with magnetic resonance angiography and in one case with a formal arteriogram. Eight of the nine patients remain alive at a mean of 3.7 years after diagnosis. None have experienced hemorrhage or other symptoms referrable to fusiform dilatation of the carotid artery, which is believed to result from surgical manipulation of the carotid artery.

Adolescent↗

PubMed1990

Recurrent intracranial ependymomas in children. Survival, patterns of failure, and prognostic factors.

Thirty-six pediatric patients (ages 0.8-16.8 years) with recurrent intracranial ependymoma were treated for a total of 52 separate cases of relapse from 1970 to 1989. Therapy consisted of surgery in 33 cases and chemotherapy in 38 cases. Twelve patients received radiation at the time of first relapse, and five of these 12 who had initially been treated with surgery and chemotherapy alone were irradiated to full dose. The 2-year actuarial survival and progression-free survival (PFS) rates are 29% and 23%, respectively. Two-year survival after treatment of first relapse is 39%. Of the 52 cases, there have been 44 subsequent relapses (and one septic death), three of which have occurred in the five patients treated with definitive radiation. Twenty-seven relapses have occurred exclusively with local disease. Eight patients failed with disease outside as well as in the primary site. Survival was better for patients who had histologically benign lesions at relapse (53% versus 9%, P less than 0.02), and for patients in first versus subsequent relapse (p less than 0.005). Cisplatin and etoposide (VP-16) appeared to be the most active chemotherapeutic agents. The authors conclude that some patients with histologically benign ependymoma at first relapse may benefit from aggressive therapy, with occasional long-term, progression-free survival possible. Patients with malignant lesions, or patients who relapse a second time, are less likely to benefit from conventional therapy for a significant period of time.

Actuarial Analysis↗

PubMed1990

Results of treatment of children with recurrent medulloblastoma/primitive neuroectodermal tumors with lomustine, cisplatin, and vincristine.

Primitive neuroectodermal tumors/medulloblastoma (PNET/MB) are the most common posterior fossa tumors in childhood. Despite surgery and radiation therapy, 40% to 50% of children with PNET/MB will have recurrent disease. Various chemotherapeutic agents are transiently effective in recurrent PNET/MB, but long-lasting responses are rarely attainable. To increase the rate and duration of response in children with recurrent PNET/MB, the authors treated seven patients (ages 2-18 years; median, 10 years) with lomustine (CCNU) (100 mg/m2), cisplatin (CPDD) (90 mg/m2) and vincristine (VCR) (1.5 mg/m2; maximum, 2 mg) in a 6-week cycle for a maximum of eight cycles. Six of six evaluable patients responded to chemotherapy. Four patients had a complete response; three with complete disappearance of tumor by imaging studies; and one with eradication of extraneural disease for a median of 24 months from relapse (13-29 months). Overall disease-free survival was 18.5 months. All six patients have subsequently died of recurrent tumor. Major toxicities consisted of reversible bone marrow suppression (six of six), high frequency hearing loss (six of six) and decreased renal function (three of six). All patients required dosage modification for toxicity. A regimen of CCNU, VCR, and CPDD is effective therapy in children with relapsed PNET/MB and can produce relatively long-term disease control with good quality of life. Further investigation into the efficacy of this combination as adjuvant chemotherapy in newly diagnosed high-risk PNET/MB is now being performed.

Adolescent↗

PubMed1990

Blood flow and metabolism in vasogenic oedema.

The relationship between white matter cerebral blood flow (CBF) and glucose metabolism (LCMRgl) was studied in a plasma infusion model of vasogenic oedema in cats. LCBF as determined by iodoantipyrine was found to be significantly decreased in oedematous white matter (17.3 +/- 1.5 ml/100 gm/min) when compared with contralateral control white matter (24.8 +/- 1.8 ml/100 gm/min). If the values for oedematous brain were corrected for dilution, however, the LCBF averaged 25.3 +/- 1.7 ml/100 gm/min, which was the same as control. LCMRgl was found to be significantly increased in plasma-infused white matter (16.3 +/- 2.2 mumol/100 gm/min), compared with control white matter (10.7 +/- 1.3). This difference remained despite correction for dilution and recalculation of LCMRgl values based on altered kinetic constants found in oedematous brain. A similar increase in LCMRgl was noted with saline infusion oedema. It is concluded that increased tissue water does not alter CBF, but does induce an increase in anaerobic metabolism.

Animals↗

PubMed1990

Pediatric brainstem glioma. Post-radiation clinical and MR follow-up.

Thirty-four pediatric patients, twenty with presumed and fourteen with biopsy or autopsy proven brainstem gliomas were imaged by CT and MR before radiation therapy. Twenty-eight patients received radiotherapy. Of these, eighteen fit the protocol for combined clinical and MR post-treatment evaluation. No cases of radionecrosis were seen at autopsy. This study shows that MR can demonstrate tumor response to radiation therapy, tumor progression prior to clinical deterioration, post-treatment cyst formation and hemorrhage. Although MR clinical correlation was not optimal on six week post-treatment evaluation, 4-10 month post-treatment MR scanning correlated well with clinical evaluation. MR appears useful in post-therapeutic monitoring of tumor response.

Adolescent↗

PubMed1990

Intracranial ependymomas in children.

Between 1970 and 1988, 51 children with intracranial ependymal tumors (33-infratentorial, 18-supratentorial received initial treatment at the University of Pennsylvania. Therapy consisted of total or near total tumor resection in 15 patients and partial resection or biopsy in 36. Postoperative irradiation alone was given to 18, chemotherapy to 4, and a combination of these two modalities to 26. Patients have been followed for a median period of 7.75 years. The 5-year actuarial survival and progression-free survival (PFS) rates are 46% and 30%, respectively. Of the 30 patients who have progressed, 29 did so locally and one died before the site of failure could be determined. Six patients also had disease outside the primary site at relapse; three of them had received craniospinal irradiation. Local control was significantly better for patients whose tumor dose exceeded 4500 cGy (32% vs. 0%, p = .01) and for Caucasian patients (34% vs. 15%, p =.05). Survival was better for patients who were over 4 years of age at diagnosis (55% vs. 30%, p = .04), for patients who received local radiation doses above 4500 cGy (51% vs. 18%, p = .01), and for Caucasian patients (43% vs. 14%, p = .01). Extent of resection, histology, location, the use of cranial or craniospinal irradiation, and the use of chemotherapy did not significantly impact on survival. We conclude that the inability to control local disease remains the single most important factor leading to treatment failure. Older age, higher local radiation dose, and Caucasian race appear to be the only favorable prognostic factors.

Adolescent↗

PubMed1990

Localized 31P magnetic resonance spectroscopy of large pediatric brain tumors.

Fourteen children aged 1 week to 16 years, with a variety of large or superficial brain tumors, underwent localized in vivo 31P magnetic resonance spectroscopy of their tumor. Quantitative spectral analysis was performed by measuring the area under individual peaks using a computer algorithm. In eight patients with histologically benign tumors the spectra were considered to be qualitatively indistinguishable from normal brain. The phosphocreatine/inorganic phosphate ratio (PCr/Pi) averaged 2.0. Five patients had histologically malignant tumors; qualitatively, four of these were considered to have abnormal spectra, showing a decrease in the PCr peak. The PCr/Pi ratio for this group averaged 0.85, which was significantly lower than that seen in the benign tumor group (p less than 0.05). No difference between the two groups was seen in adenosine triphosphate or phosphomonoesters. It is concluded that a specific metabolic "fingerprint" for childhood brain tumors may not exist, but that some malignant tumors show a pattern suggestive of ischemia.

Adenosine Triphosphate↗

PubMed1990

Cerebral venous oxygen content as a measure of brain energy metabolism with increased intracranial pressure and hyperventilation.

In order to test the hypothesis that the cerebral arteriovenous oxygen difference (AVDO2) and venous oxygen content (VO2) could be used to monitor brain energy metabolism in the setting of increased intracranial pressure (ICP). 12 cats were studied with 31P-magnetic resonance spectroscopy. six cats were subjected to intracranial hypertension by cisternal infusion of saline. Energy failure occurred at an average AVDO2 of 8.4 +/- 3.2 vol% (+/- standard deviation) (range 4.7 to 14.7 vol%). The VO2 at the point of metabolic failure averaged 1.45 +/- 0.6 vol% and extended over a narrower range (1.0 to 2.9 vol%). In an additional six cats, ICP was raised to the threshold of metabolic failure and hyperventilation was then instituted (pCO2 10 to 18 torr). Five of the six cats experienced a drop in VO2 with hyperventilation. In two of these animals, hyperventilation resulted in a VO2 of 1.1 vol% or less and in metabolic failure as evidenced by a fall in phosphocreatine. It is concluded that a VO2 of less than 2 vol% is correlated with brain ischemia and that the safety of hyperventilation in the setting of increased ICP can be monitored by the use of VO2.

Animals↗

PubMed1990

Medulloblastomas.

It is obvious that the past decade has witnessed considerable progress in the management of children with medulloblastoma. Better surgical technique has led to more aggressive surgery with less morbidity. The use of staging has led to reduction in radiation therapy doses in some patients and will, it is hoped, lead to better neuropsychological outcome. The use of adjuvant chemotherapy in high-risk patients is delaying recurrence. It remains unknown, however, whether the patient with a medulloblastoma is ever "cured." Certainly, in the future, control of this tumor will depend on new therapeutic modalities, which will be developed on the basis of a better understanding of the biology of these primitive tumors. A better understanding of tumor immunology, cytogenetics, and biochemistry is a goal for the future.

Adolescent↗

PubMed1989

Suprasellar germinomas in childhood. A reappraisal.

Germinomas in childhood may arise in both the suprasellar and pineal region, and outcome has been reported to be worse for suprasellar germinomas with a 5-year survival rate of 20% as compared to 60% for pineal germinoma. To determine the factors impacting on outcome, the results of a uniform treatment approach were evaluated and included primary surgical debulking (PSD) and systemic craniospinal axis radiation (CSRT) for suprasellar germinomas. Between 1976 and 1985 ten consecutive patients (seven females, three males) with the pathologically confirmed diagnosis of suprasellar germinoma were treated. Outcome was compared to four male patients with pineal germinoma treated over the same time period and series of patients reported in the literature. At diagnosis the mean age of patients with suprasellar germinoma was 13.9 years (range, 8.9 to 9.4 years). Symptoms were present for a mean of 18 months (range, 2 to 72 months) prior to diagnosis and included diabetes insipidus, anterior pituitary dysfunction, decreased vision, headache, vomiting, and diplopia. Staging studies, including myelography (n = 4) and cerebrospinal fluid cytology (n = 7), disclosed dissemination in only one child. Surgical treatment included biopsy in three cases, partial resection in five, and total resection in two; no permanent postsurgical complications were noted. The mean radiation therapy dose to the tumor site was 4953 cGy (range, 4400 to 5250 cGy) and to the spine 3354 cGy (range, 3000 to 4000 cGy). Patients were followed for a mean period of 5.1 years (range, 1.9 to 10.5 years). One patient with SG who did not receive treatment initially developed a pineal tumor after diagnosis; she was treated with PSD and CSRT and is asymptomatic 5 years later. All the remaining patients are alive and remain disease-free. Surgical resection and CSRT results in excellent disease control for children with suprasellar germinomas, and outcome is similar to those patients with pineal germinoma.

Adolescent↗

PubMed1989

Isochromosome 17q in primitive neuroectodermal tumors of the central nervous system.

We have prepared karyotypes from 22 primitive neuroectodermal tumors (PNETs) from pediatric patients ranging in age from 10 months to 16 years. Twenty-one cases were newly diagnosed, primary, posterior fossa tumors. One case was a recurrent tumor in a patient previously treated with radiation. Cytogenetic results were obtained from direct preparations and/or short-term (1-10 day) culture. Three tumors had apparently normal karyotypes. Nineteen tumors demonstrated numerical and/or structural abnormalities. The most frequent structural chromosomal changes were deletions and nonreciprocal translocations. Four tumors contained double minutes. Several chromosomes appear to be nonrandomly involved in PNETs. These include chromosomes 5, 6, 11, 16, 17, and a sex chromosome. The most consistent change, however, was an i(17q), present in one-third (8/22) of the cases. Strikingly, in three of these eight tumors, the i(17q) was the only structural abnormality observed. An i(17q) is not specific for pediatric PNETs, as it is also seen in leukemias and other solid tumors. However, in PNETs it may be a primary change related to tumor development and/or progression. Clinically, there was no correlation of the cytogenetic findings with histologic features of the tumors, size of the tumor, extent of metastasis, or surgical resection.

Adolescent↗

PubMed1989

Radiographic features and prognosis in bronchioloalveolar carcinoma; a local experience.

The prognosis of 20 patients with histologically proven bronchioloalveolar carcinoma was assessed in the light of their radiographic features and symptoms at presentation. Radiographically, half the patients were classified as having focal disease of which 60% were focal consolidation. Other focal presentations were, a mass lesion in three cases and a single 3 cm nodule in one case. Those with diffuse disease presented with either coarse widespread nodules or diffuse alveolar opacification with or without a focal area of consolidation. All patients were symptomatic at presentation but the severity of the symptoms bore no relation to the radiological findings. Seven cases with focal disease underwent thoracotomy, five of which had evidence of hilar and mediastinal lymph node involvement. They included a case presenting with a nodule, two with a mass and four with focal consolidation. The survival following surgery was generally better with those with a mass or nodule but one case with focal consolidation remains alive 10.5 years following surgery compared with the longest survivor of 4.5 years with a mass. Both these relatively long-term survivors had no histological evidence of hilar or mediastinal lymph node involvement compared with the other surgical cases. The median survival in cases without surgery was one month. The prognosis was better in patients with focal disease where surgery was performed and we feel that a local area of consolidation should be treated as focal disease and surgical resection considered for these patients.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed1989

Use of 19F NMR spectroscopy for measurement of cerebral blood flow: a comparative study using microspheres.

19F NMR was used to determine washout curves of an inert, diffusible gas (CHF3) from the cat brain. The cerebral blood flow was estimated from a bi- or tri-phasic fit to the deconvoluted wash-out curve, using the Kety-Schmidt approach. Cerebral blood flow values determined by 19F NMR show the expected responsiveness to alterations in Paco2, but are approximately 28% lower than cerebral blood flow values determined simultaneously by radioactive microsphere techniques. High concentrations of CHF3 have little effect on intracranial pressure, mean arterial blood pressure or Paco2, but cause small changes in the blood flow to certain regions of the brain. We conclude that 19F NMR techniques utilizing low concentrations of CHF3 have potential for the noninvasive measurement of cerebral blood flow.

Animals↗

PubMed1989

Magnetic resonance imaging of lipomyelomeningocele and tethered cord.

The operative and magnetic resonance image (MRI) findings of 25 patients with the diagnosis of lipomyelomeningocele and/or tethered cord were compared. Postoperative MRI scans of eight patients, five of whom were in stable condition, were also compared with the preoperative studies. In this review there was one false negative MRI scan and four MRI scans in which the relationship of the lipoma to the conus or filum was not demonstrated accurately. In six patients, incidental intramedullary cystic lesions at the conus were identified by MRI scan. All eight postoperative (1 month to 2 years) scans demonstrated no change in the level of the conus from the preoperative study. MRI is an accurate screening modality in the initial diagnosis of occult spinal dysraphism. MRI was not useful in the postoperative evaluation of lipomyelomeningocele and the tethered cord, since the caudal, posterior displacement of the conus was unchanged in all studies.

Adolescent↗