Biomedical subjects
M S Edwards
Publications and source records attributed to M S Edwards.
Hyperammonemia and neonatal herpes simplex pneumonitis.
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MR imaging of pineal tumors.
MR images of pineal region tumors were analyzed in 26 patients with histologically proved tumors: seven germ-cell tumors, six astrocytomas, five teratomas, three pineoblastomas, two meningiomas, one dermoid, one epidermoid, and one metastasis. In an attempt to identify specific MR characteristics of these lesions, Gd-DTPA was administered to six patients. CSF and blood serum were assayed for alpha-fetoprotein (AFP) and human chorionic gonadotropin-beta subunit (HCG-beta) in 18 patients. MR findings were correlated with age, sex, the presence of biochemical tumor markers, and surgical outcome. We found that the most important factors in the determination of tumor type were the patient's age and the tumor markers. Increased levels of both HCG-beta and AFP were specific for patients with malignant teratomas and undifferentiated germ-cell tumors. HCG-beta alone was elevated in the patient with choriocarcinoma; only AFP was elevated in the patient with an endodermal sinus tumor. Tumor markers were not present in other patients in this series. The tumor size and the presence of fat were also helpful in determining tumor type. Hemorrhage was rare, seen only in the patient with a choriocarcinoma. Gd-DTPA did not enhance diagnostic specificity but aided in the detection of tumor seeding through CSF. We conclude that, although MR is sensitive in the detection of pineal region tumors and provides superb anatomic detail, MR signal characteristics are usually nonspecific. Correlation with the patient's age and the tumor markers significantly improves diagnostic accuracy.
Cryptic vascular malformations of the spinal cord: diagnosis by magnetic resonance imaging and outcome of surgery.
The cases of seven patients with intramedullary, cryptic vascular malformations of the spinal cord are reported. In all patients, the clinical course was progressive; a Brown-Séquard syndrome was the most common presenting symptom complex. Magnetic resonance (MR) imaging was performed in all patients. The pattern seen most often was a focus of high signal (on both T1- and T2-weighted MR images) surrounded by a larger zone of low signal (best seen on T2-weighted images), and was remarkably similar for all patients. Six patients underwent surgical exploration; removal of the lesions halted the progression of symptoms in five patients, and one patient had worsened sensory function after surgery. Motor function did not decrease postoperatively in any patient. The one patient who refused surgery has continued to decline neurologically. Histopathological examination of surgical specimens showed a cavernous malformation in one patient, a venous malformation in one, venous varices in two, and organizing hematomas in two; these findings are markedly different from those in previously reported cases of cryptic vascular malformations.
Methods for evaluating the protective activity of intravenous immunoglobulins for neonatal pathogens: entanglement or encouragement?
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Coagulase-negative staphylococcal bacteremia in neonates: confusion continued.
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Group B streptococcal infections.
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Disseminated mucormycosis in an infant with methylmalonicaciduria.
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Renal transplant diet recommendations: results of a survey of renal dietitians in the United States.
A survey of dietitians at renal transplant centers in the United States was conducted to identify diet modifications currently used for nondiabetic adults after kidney transplantation. The survey focused on the diet recommended for the first 21 days after successful transplantation. Questionnaires were mailed to 100 centers randomly selected from a comprehensive list obtained through the Organ Transplant Coordinating Office of the Texas Medical Center, Houston. A 66% response rate was obtained. The results of the survey showed that dietitians were most frequently recommending 1.2 to 1.5 gm protein per kg body weight, 40% to 50% of total energy as carbohydrate, a fat intake of less than 30% of total energy, and an energy level consistent with achieving or maintaining desirable body weight. Sodium intake was most commonly restricted to 2 to 4 gm, whereas potassium and phosphorus intakes were individualized according to the patient's serum values. Comments on the returned questionnaires indicated that many institutions were reviewing and updating their transplant diet to include a polyunsaturated fat to saturated fat ratio and restrictions of cholesterol and simple sugars. The findings of the survey indicated that the renal transplant diet should focus on optimal protein and energy intake as well as restriction of simple sugars, total fat, cholesterol, and saturated fat to restore nitrogen balance and minimize clinical symptoms of post-transplant diabetes and hyperlipidemia.
Pineocytomas.
Six cases of histologically proven pineocytoma are reported. The diagnosis was established by surgery in five cases and at autopsy in one. All patients received focal radiation therapy (4500 to 5400 cGy). Two patients had local recurrences at 1 and 48 months and subsequently died of tumor. A third patient died of Alzheimer's disease 29 years after the initial presentation. Three patients are alive with no evidence of disease at 21+, 52+, and 84+ months after treatment. Tumor dissemination occurred after a local recurrence in one patient. We found no evidence of recurrence outside the irradiated field unless there was an initial recurrence at the primary tumor site. We recommend postoperative staging for all patients with pineocytoma and focal radiation therapy if local disease alone is found. Craniospinal radiation therapy appears to be justified only if tumor dissemination is documented on staging tests.
Survival and quality of life after interstitial implantation of removable high-activity iodine-125 sources for the treatment of patients with recurrent malignant gliomas.
Between January 1980 and January 1988, 95 evaluable patients with recurrent, unifocal, supratentorial malignant gliomas were reirradiated with high-activity iodine-125 sources implanted directly into tumor in afterloaded, removable catheters using computerized tomography-directed stereotaxy. A tumor dose of 5270-15,000 cGy was delivered at a maximum distance of 0.5 cm from the rim of the contrast-enhancing mass seen on CT scans. The median survival for the 50 patients with anaplastic astrocytoma was 81 weeks and for 45 patients with glioblastoma multiforme it was 54 weeks. The 18- and 36-month survival rates for patients with anaplastic astrocytoma were 46% and 28%, respectively; the 18- and 36-month survival rates for patients with glioblastoma multiforme were 22% and 8%, respectively. Because of clinical deterioration, increasing steroid dependency, and increasing mass effect at the implantation site seen on CT scans, necrotic tissue was excised from 47 patients (49%) at craniotomy; in some patients, tumor was mixed with necrotic tissue. The survival of reoperated patients was significantly longer compared with patients who did not undergo this procedure. Serial determination of the Karnofsky Performance Score (KPS) showed that there was no significant deterioration for the group as a whole during the 6 months immediately after implantation. At 18 months, 33 of the patients were alive; KPS ranged between 50 to 90 (mean 79) and 67% were steroid dependent. At 36 months, 18 patients were alive; 17 patients were evaluable with KPS that ranged between 40 to 90 (mean 76) and 53% were steroid dependent. Eleven of the 17 evaluable long-term survivors had a KPS of 80 or higher with a mean of 87. Interstitial brachytherapy may provide long-term survival in selected patients with recurrent malignant gliomas who have been irradiated previously with conventional teletherapy. The quality of life in the majority of long-term survivors appears to be quite satisfactory. Further attempts to control tumor growth using this modality appear to be warranted.
Penetration of cefuroxime into ventricular fluid in cerebrospinal fluid shunt infections.
The penetration of intravenously administered cefuroxime into ventricular fluid was assessed in five pediatric patients with ventriculoperitoneal shunt infections and in one with a ventriculostomy infection. Patients received a total dose of 200 to 230 mg of cefuroxime per kg of body weight per day administered at 8-h intervals. Levels of cefuroxime in ventricular fluid ranged from 1.6 to 22.5 micrograms/ml and were associated with cerebrospinal fluid bactericidal titers ranging from less than 1:2 to 1:16 against infecting staphylococcal isolates. Five infections were cured with cefuroxime monotherapy. On the basis of MIC data, one patient had vancomycin substituted for cefuroxime and the infection was cured.
Revised classification of posterior fossa cysts and cystlike malformations based on the results of multiplanar MR imaging.
MR and clinical data on 31 patients with posterior fossa CSF collections were analyzed. A clear separation of these patients into classical categories was not possible because of new information obtained from the MR images. We present a new classification of these disorders. The Dandy-Walker malformation, Dandy-Walker variant, and mega-cisterna magna seem to represent a continuum of developmental anomalies of the posterior fossa. A possible embryologic basis for this continuum is suggested. Discrete posterior fossa CSF collections that are clearly separate from the fourth ventricle and vallecula are classified as posterior fossa cysts. Posterior fossa CSF collections that communicate with the fourth ventricle and are associated with cerebellar atrophy are classified as prominent cisterna magna. Both the Dandy-Walker complex and posterior fossa cysts can cause enlargement of the posterior fossa and scalloping of the inner table of the occipital bone. The Dandy-Walker complex presents with seizures, developmental delay, and enlarging head size; it requires CSF diversion when associated with hydrocephalus. Posterior fossa cysts present with symptoms of a posterior fossa mass; they generally require surgical resection. Prominent cisterna magna is a result of degenerative disorders and requires no surgical therapy. This new classification facilitates both diagnosis and therapy of these disorders. MR revealed that disorders previously referred to as the Dandy-Walker malformation, the Dandy-Walker variant, and the mega-cisterna magna actually are not separate entities, but appear to represent steps on a continuum of developmental anomalies of the posterior fossa. Because of this, we suggest a new term, the Dandy-Walker complex, be used to describe this continuum.
Hyperfractionated radiation therapy for brain-stem glioma: a phase I-II trial.
Fifty-three patients (19 adults and 34 children) harboring brain-stem glioma were treated with hyperfractionated radiation therapy (100 cGy twice a day, 5 days/wk, to a total dose of 7200 cGy). For the entire group, the median time to tumor progression (TTP) was 59 weeks (adults 66 weeks, children 44 weeks) and the median survival time was 74 weeks (adults 92 weeks, children 64 weeks). Statistically significant prognostic factors associated with a decrease in TTP and median survival times (adults less than children) were: patient's age, a clinical history of less than 2 months, widespread brain-stem dysfunction, and a diffuse tumor as seen on magnetic resonance imaging. A finding of glioblastoma multiforme at histological analysis was associated with a statistical trend toward poorer survival, but in general tumor histology was not predictive of outcome. No evidence of an increase in acute or delayed radiation toxicity was seen with this fractionation schedule and total dose. This study suggests that hyperfractionation prolongs the TTP and survival time for many patients with brain-stem glioma. However, there remains a group of patients who are only moderately helped by this technique and for whom more aggressive treatment is warranted.
Clinical herpes zoster shortly following primary varicella in two HIV-infected children.
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The effect of bromodeoxyuridine and ultraviolet light on 9L rat brain tumor cells.
Incorporation of the thymidine analog bromodeoxyuridine (BrdUrd) into DNA increases the sensitivity of a cell to uv light. We have examined the effect of uv light on cell killing and alkaline elution profiles in 9L rat brain tumor cells pretreated with BrdUrd. Combination treatment with BrdUrd and uv irradiation produced a dose enhancement ratio of 3.8 at the 10% survival level compared with uv-radiated control cells; cell killing depended on both the time of treatment and the concentration of BrdUrd used for incubation. Sequential treatment caused single-strand breaks and DNA-protein crosslinks in the portion of DNA containing BrdUrd; uv irradiation alone caused very few strand breaks and no DNA-protein crosslinks. Because of the presence of both lesions in cells treated with BrdUrd and uv light, it was possible to calculate crosslinking factors without using a charging X-ray dose to induce strand breaks, the method commonly used with crosslinking drugs. Results of repair studies suggested that single-strand breaks are repaired more rapidly than are DNA-protein crosslinks.
Traumatic monocular blindness and associated carotid injuries.
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Immunization of pregnant women with a polysaccharide vaccine of group B streptococcus.
Immunization of pregnant women with a polysaccharide vaccine of group B streptococcus is a promising strategy for the prevention of perinatal infections caused by group B streptococci. To explore the feasibility of this strategy, we vaccinated 40 pregnant women at a mean gestation of 31 weeks with a single 50-microgram dose of the Type III capsular polysaccharide of group B streptococcus. The only adverse effect detected was a mild local reaction in nine women (22 percent). Of the 35 women with low or unprotective antibody levels before immunization (less than 2 micrograms per milliliter), 20 (57 percent) responded to the vaccine. The geometric mean antibody level rose from 1.3 to 7.1 micrograms per milliliter four weeks after vaccination (P less than 0.02), and these levels persisted at delivery and three months post partum. Sixty-two percent of the vaccine-induced immunoglobulin in the mothers was IgG, which readily crosses the placenta. Infant antibody levels in cord serum correlated directly with maternal antibody levels at delivery (r = 0.913, P less than 0.001). Of the 25 infants born to women who responded to the vaccine, 80 percent continued to have protective levels of antibody at one month of age and 64 percent had protective levels at three months. Serum samples from infants with greater than or equal to 2 micrograms of antibody to Type III group B streptococcus per milliliter uniformly promoted efficient opsonization, phagocytosis, and bacterial killing in vitro of Type III strains. This effect could be mediated exclusively by the alternative complement pathway. Although this vaccine with an overall response rate of 63 percent is not optimally immunogenic, we conclude that maternal immunization is feasible and can provide passive immunity against systemic infection with Type III group B streptococcus in the majority of newborns. Larger trials with better vaccines will be required to evaluate the safety and clinical effectiveness of this strategy.