Biomedical subjects

Y Umebara

Publications and source records attributed to Y Umebara.

10 recordsLinked to original sources

PubMed1996

MIB-1 staining index and peritumoral brain edema of meningiomas.

BACKGROUND: Growth rates and tumor aggressiveness of meningiomas are thought to be closely related to brain edema development. However, histopathologic data alone are not consistently accurate predictors of the behavior and clinical course of a meningioma. METHODS: The authors examined 57 histologically proven intracranial meningiomas to identify factors, including growth fractions determined by MIB-1 immunostaining, that may influence the development of meningioma-associated peritumoral brain edema. There were 54 benign, 2 atypical, and 1 anaplastic meningiomas. The MIB-1 staining index (SI) percentage was defined as the number of MIB-1 positive cells divided by the total number of tumor cells in a 1.037-square millimeter area on the slide. The extent of peritumoral brain edema was determined using preoperative magnetic resonance imaging. The extent of edema was classified as Grade 0,1, or 2 (GR0, GR1, or GR2), in order of increasing severity. RESULTS: The MIB-1 SIs of the 57 cases ranged from 0.06-6.8% (median, 0.80%). There were 26 GR0, 20 GR1, and 11 GR2 edema cases. The MIB-1 SI rose in order of increasing edema severity. There was a statistically significant correlation between the MIB-1 SI and the extent of brain edema (P<0.0001), and also between the tumor size and the extent of brain edema (P=0.001). Meningothelial and atypical/anaplastic meningiomas were associated with peritumoral brain edema more often than any other subtype (P<0.005). CONCLUSIONS: Growth fractions, as determined by MIB-1 immunostaining, rise with increasing severity of peritumoral brain edema, indicating a close relationship between tumor aggressiveness and edema development.

Adult↗

PubMed1996

Is unchanged tumor volume after radiosurgery a measure of outcome?

We report three patients who underwent Gamma Knife radiosurgery for benign tumors (meningioma, neurinoma and hemangioblastoma), in whom an 'unchanged tumor volume' demonstrated by postirradiation follow-up neuroimaging could be regarded as a successful treatment results, as compared with preradiosurgery tumor growth. It is our view that unless significant tumor growth has been observed before radiosurgery, 'unchanged in size' after radiosurgery cannot be regarded as a successful treatment result. Because relatively few hemangioblastoma patients have been treated radiosurgically, this report emphasizes the course of one case with hemangioblastoma.

Adult↗

PubMed1996

Gamma knife radiosurgery for brain tumors: postirradiation volume changes compared with preradiosurgical growth fractions.

The postradiosurgical volume changes were compared with preradiosurgical growth fractions defined as the tumor doubling time and/or MIB-1 staining index in 14 patients who underwent gamma knife radiosurgery for treatment of various brain tumors. The mean preradiosurgical observation period using neuroimaging techniques was 750 days (range 80-2967 days), and the mean follow-up period after radiosurgery was 664 days (range 328-1100 days). There were four neurinomas, three meningiomas, two craniopharyngiomas, two gliomas, one hemangioblastoma, one pituitary tumor, and one intracranially infiltrative lacrimal gland tumor. The mean patient age at the time of radiosurgery was 52 years (range 8-81 yrs). There were eight males and six females. Following gamma knife radiosurgery, the mean tumor half time was estimated to be 789 days (range 124-2101 days), and the volume reduction against the preradiosurgical tumor volume ranged from 6.3% to 76.1%. This study demonstrates that gamma knife radiosurgery can control tumor growth despite the lack of a correlation with preradiosurgical tumor growth or staining indices for MIB-1. Analyses of this type are essential to show that an "unchanged tumor volume" as demonstrated by postradiosurgery follow-up neuroimaging can be regarded as showing successful radiosurgery.

Adolescent↗

PubMed1996

Perioperative antimicrobial prophylaxis in neurosurgery: clinical trial of systemic flomoxef administration and saline containing gentamicin for irrigation.

The efficacy of a new protocol consisting of a prophylactic antibiotic regimen of peri- and postoperative intravenous administration of flomoxef and irrigation of the operative field with saline containing gentamicin was assessed by comparing infection rates in two consecutive series of patients who underwent neurosurgical procedures. Group A received postoperative flomoxef administration, with saline containing no antibiotics for irrigation, from July 1988 to December 1989. Group B received the new protocol from January 1990 to December 1991. For further evaluation, this protocol was continued in most patients who underwent surgery from January 1992 through December 1993 (Group C). Only adult or adolescent patients who underwent clean neurosurgical procedures were included. The number of patients and procedures in each group were: 76 patients (97 procedures) in Group A, 103 (133) in Group B, and 107 (137) in Group C. There were no significant differences between Groups A and B in age, sex, clinical category, coexistent disease, clinical outcome, surgical procedures, general anesthesia, emergency operation, steroid administration, and the timing (season), duration, and frequency of surgery. Meningitis developed in three patients and subcutaneous infection in one in Group A. None of the patients in Group B experienced postoperative infection. This difference in infection rates (4.1% vs. 0%) was statistically significant (p = 0.0305). Furthermore, no postoperative infections developed in the Group C patients. The most appropriate interval for multiple dose administration was determined by analyzing intraoperative time-related changes in the serum flomoxef concentration during surgery in 21 recent patients. Serum flomoxef concentrations fell below therapeutic levels (3.0 micrograms/ml) by the 6th post-administration hour in 70% of patients. We conclude that this antibiotic regimen significantly reduces the postoperative infection rate following neurosurgical procedures. Multiple dose administration of flomoxef is recommended when the duration of surgery is 6 hours or more.

Adult↗

PubMed1995

Growth rate of intracranial meningioma: tumor doubling time and proliferating cell nuclear antigen staining index.

The relationship between tumor doubling time, estimated by serial computed tomography (CT), and the proliferating cell nuclear antigen (PCNA) staining index of the tumor specimen was analyzed in 12 patients with nine partially or subtotally resected meningiomas and three meningiomas which recurred after gross total removal. There were nine meningothelial and three fibrous meningiomas. Malignant meningiomas and hemangiopericytomas were excluded. Serial CT was performed at various intervals ranging from 354 to 2007 days. Formalin-fixed, paraffin-embedded archival tissues were immunohistochemically stained using the avidin-biotin complex method with monoclonal antibody against PCNA. Percentages of PCNA-positive cells were calculated in 10 microscopic fields to determine the mean PCNA staining index. PCNA staining indexes varied from 0.13% to 7.46%. The tumor doubling time ranged from 197 to 7943 days and demonstrated a significant inverse rank correlation with the PCNA staining index (r = -0.89, p = 0.003). Meningiomas with PCNA staining indexes higher than 1% have comparatively short tumor doubling times of less than 5 years. PCNA immunostaining is a useful method for evaluating the proliferative activity of meningiomas.

Biomarkers, Tumor↗

PubMed1993

Recurrence of symptomatic Rathke's cleft cyst: a case report.

A 65-year-old man presented with bitemporal hemianopsia. He had undergone frontal craniotomy for a Rathke's cleft cyst associated with narrowed visual field 8 years earlier. His vision had returned to normal soon after surgery and he remained asymptomatic until the present complaint. Neurodiagnostic imaging revealed a recurrence of the intrasellar cyst extending into the suprasellar cistern. His vision improved rapidly after a second surgery. The histological findings were the same as those of the previous operation; the cyst wall was composed of a single layer of ciliated columnar epithelium resting on a collagenous connective tissue stroma.

Aged↗

PubMed1993

Penetration of intravenous antibiotics into brain abscesses.

INTRA-ABSCESS CONCENTRATIONS OF the intravenously administered latamoxef (LMOX, moxalactam in the United States) and cefotetan (CTT), were studied in 11 patients with intracranial abscess. None of these patients underwent surgical ablation of the abscess. In all cases, the abscess was aspirated, and multiple aspirations were required in five patients. Antibiotic concentrations in 18 aspirates were, therefore, determined by the agar well method. LMOX concentrations in 16 aspirates drawn from nine brain abscess cases ranged from 0 to 10.9 micrograms/ml, with a mean (standard deviation) of 4.18 (3.04) micrograms/ml. The CTT concentration in one patient with a brain abscess was 8.51 micrograms/ml, and the LMOX concentration in the one remaining patient with subdural empyema was 5.20 micrograms/ml. In one patient, the serum-to-pus penetration rate of LMOX was estimated to be 0.11 against the peak value of the concentration in serum or 0.44 against the simultaneously obtained level in serum. Significantly higher concentrations of LMOX were produced in abscess cavities with multiple-dose administration or by prior drainage of pus. More-advanced stages of local inflammation, as demonstrated by computed tomography, correlated with higher concentrations. However, the routine indexes of systemic inflammation, such as body temperature, white blood cell count, and level of C-reactive protein in serum, cannot be used to predict the concentration present in intracerebral pus. A tendency for LMOX concentrations in pus obtained after single dose-administration to decrease with increasing duration from symptom onset to sampling was observed but was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Asymptomatic calcified chronic subdural hematoma--report of three cases.

Three adults with asymptomatic calcified chronic subdural hematoma are described. Plain skull x-ray films following head trauma disclosed calcified chronic subdural hematomas and computed tomography (CT) revealed large, frontoparietal, calcified hematomas in all cases. A 49-year-old male received hematoma removal because of his lower age and CT evidence of cerebral compression. An 83-year-old male was not operated on and remained asymptomatic. The third patient died of trauma-related injuries. In the non-elderly, surgery for asymptomatic calcified chronic subdural hematoma with significant cerebral compression should be considered for relief of cerebral compression and prevention of possible future brain damage.

Aged↗

PubMed1993

Solitary pyogenic thalamic abscess--two case reports.

We report two patients with solitary thalamic abscesses, occurring among 91 consecutive patients (2.2%) with computed tomography (CT)-diagnosed and surgically-verified brain abscess experienced in our college during 1975 to 1991. A 9-year-old girl with congenital heart disease experienced frequent vomiting followed by left hemiparesis and deterioration of consciousness. CT demonstrated a right thalamic ring-enhanced lesion. Purulent material was aspirated via a burr hole. She died of heart failure on the 5th postoperative day. Autopsy disclosed diffuse brain swelling and an encapsulated abscess in the right thalamus, which had ruptured into the third ventricle. A 30-year-old female experienced headache, nausea, and vomiting, which progressed to somnolence and right hemiparesis. CT demonstrated a left thalamic ring-enhanced lesion. Purulent material was aspirated by stereotactic procedures. All symptoms had resolved by the end of the 2nd postoperative week.

Adult↗

PubMed1992

Postoperative neurosurgical infection and antibiotic prophylaxis.

The most suitable antibiotics for chemoprophylaxis in neurosurgery and risk factors for postoperative neurosurgical infection were investigated by retrospective analysis of 807 neurosurgical procedures in 566 patients between 1980 and 1989. Prophylactic antibiotics were administered intravenously for 6 or 7 postoperative days in all instances. The 807 operations were classified according to the antibiotics used into: 1) penicillin, 2) cephem-I, 3) cephem-II, 4) cephem-III, and 5) others. Postoperative neurosurgical infections occurred in 27 of 807 operations (3.3%), or 27 of 566 patients (4.8%). Hypertension and surgery performed in summer carried a significantly higher risk of infection. Diabetes mellitus, steroid administration, prolonged surgery, re-exploration, and surgery for hemorrhagic cerebrovascular diseases were associated with increased risk, but were not statistically significant. Infection rates by type of chemoprophylaxis were: 3.6% in the penicillin group, 3.7% in the cephem-I group, 1.7% in the cephem-II group, 5.7% in the cephem-III group, and 2.8% in the others group. This result indicates that the best choice for prophylactic antibiotic therapy may be a second-generation cephem.

Adolescent↗