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Biomedical subjects

M Blaivas

Publications and source records attributed to M Blaivas.

At least 55 records · Page 3Linked to original sources
PubMed1998

Diagnosis of spontaneous splenic rupture with emergency ultrasonography.

Rapid evaluation of the hypotensive patient in the emergency department is essential. The availability of ultrasonography in the ED, performed by emergency physicians and surgeons, has made it easier to evaluate the hypotensive trauma patient. We describe a 44-year-old man transferred to our institution from a community hospital for evaluation of syncope and hypotension with no obvious cause. On arrival the patient began to complain of slight lower abdominal pain. The patient's physical examination revealed minimal abdominal tenderness. A rapid ultrasound examination performed at bedside revealed the presence of intraperitoneal fluid. Examination of the spleen suggested likely rupture. The patient was promptly taken to surgery for splenectomy and discharged home in 4 days.

Adult↗
PubMed1998

Effect of dietary vitamin A or N-acetylcysteine on ethylnitrosourea-induced rat gliomas.

It is our hypothesis that low grade gliomas are the glial counterparts of other precancerous lesions such as colon polyps and, therefore, suitable targets for chemoprevention. Steps in the molecular progression of gliomas have been described, indicating that an accumulation of abnormalities is required for progression to a high grade and interruption of this progression might be possible. An animal model of chemical glial carcinogenesis was used to test this hypothesis. Pregnant rats were injected intravenously with ENU (ethylnitrosourea) on the 18th day of gestation to induce gliomas in the offspring, which were randomized to receive control diet, diet supplemented with vitamin A palmitate, or diet supplemented with N-acetylcysteine. Animals exposed to ENU and receiving a control diet developed brain tumors and had a shortened life expectancy compared with rats unexposed to ENU. The animals treated with NAC showed no statistically significant delay in the time to tumor and no change in the histologic grade of the tumors when compared with animals receiving control diet, but the time to death from any cause of NAC treated animals differed significantly from untreated animals. Animals receiving high dose VA had statistically significantly prolonged time to tumor, survived significantly longer than untreated animals, but had no reduction in the total number of tumors or change in the histologic grade of their tumors. The theoretical basis of these results is likely due to the putative mechanism of action of these agents. These data indicate that glioma chemoprevention is possible and deserves further exploration.

Acetylcysteine↗
PubMed1998

MIB-1 proliferation index predicts survival among patients with grade II astrocytoma.

The purpose of this study was to determine whether a relationship existed between MIB-1 labeling index (LI) percentages and survival in patients with grade II astrocytomas. From archival paraffin-embedded surgical specimens of 50 patients of the University of Michigan Medical Center with World Health Organization grade II astrocytomas, 22 patients had a Ki-67 LI of less than or equal to 2.0; and 28 patients had a MIB-1 LI of more than 2.0. Over a median follow-up interval of 10 years, ranging up to 16 years, 23% (n = 5) died of tumor in the first group while 82% (n = 23) died in the second group, a distinct difference in survival between these groups. Univariate analysis showed that a high MIB-1 predicted shorter survival (p < 0.0001), and that increased age was associated with shorter survival (p = 0.007). Gender, tumor location and radiotherapy had no significant association with survival. When adjusting for these (excluding tumor location) in the Cox proportional hazards model simultaneously, MIB-1 and age were independently prognostic. The hazard ratios were 1.301 per 1% MIB-1 LI (p = 0.0001), and 1.045 per year of age (p = 0.0028). From other studies, we know that histopathologic grade and age predict survival for glioma patients. However, even within grade II astrocytomas there is still a wide heterogeneity in how long a patient survives. We conclude that among grade II astrocytomas older patients and, independently, patients with higher MIB-1 labeling index have shorter survival.

Adolescent↗
PubMed1998

A case of respiratory muscle weakness due to cytochrome c oxidase enzyme deficiency.

Mitochondrial myopathy is a rare cause of dyspnoea and respiratory failure, usually presenting in infancy. We describe a 27 yr old woman with a partial cytochrome c oxidase enzyme deficiency causing respiratory muscle weakness and respiratory failure. The onset was acute, with no preceding respiratory symptoms. The patient was successfully treated with bilevel positive airway pressure therapy.

Adult↗
PubMed1998

Correlation of intraluminal thrombosis in brain tumor vessels with postoperative thrombotic complications: a preliminary report.

OBJECT: Thrombotic complications (deep vein thrombosis and/or pulmonary embolization [DVT/PE]) occur in 18 to 50% of patients harboring brain tumors who undergo neurosurgical procedures. Such patients are at risk for DVT/PE because of immobility, paresis, hypovolemia, and lengthy surgery. The present study was undertaken to see whether tumor patients at highest risk for DVT/PE could be identified so that augmentation of prophylactic measures might be used to reduce the incidence of thrombotic complications. METHODS: The authors conducted a retrospective analysis of 488 patients enrolled in their brain tumor registries between 1988 and 1995, identifying 57 patients (12%) with recorded symptomatic DVT, PE, or both postoperatively. In 24 of these 57 cases histological specimens were retrievable for review, allowing an in-depth analysis. Forty-five patients were lost to follow-up review, and the remaining 386 patients had no record of systemic thrombosis. Slides of pathological specimens were retrievable in 50 cases in which there was no DVT/PE. From these 50 cases, 25 were selected at random to represent the control group by a blinded observer. Seventeen (71%) of the 24 brain tumor specimens obtained in patients with DVT/PE stained positively for intraluminal thrombosis (ILT) after hematoxylin and eosin had been applied. The odds ratio associated with the presence of ILT was 17.8, with a confidence interval ranging from 4 to 79.3. No evidence of ILT was found in 22 patients (88%) within the control group (p < 0.0001, Fisher's exact test). Other factors that may predispose patients with brain tumors to DVT/PE-limb paresis, extent of tumor removal, and duration of the surgery-were also analyzed and found not to be statistically significant. Therefore, these factors were not the basis for differences seen between the study and control groups. CONCLUSIONS: These preliminary observations suggest that the presence of ILT within malignant glioma or glioblastoma tumor vessels may represent a marker of tumor-induced hypercoagulability.

Adult↗
PubMed1997

Persistent systemic production of human factor IX in mice by skeletal myoblast-mediated gene transfer: feasibility of repeat application to obtain therapeutic levels.

Myoblast-mediated gene transfer and its repeated applications were tested for achieving a long-term stable systemic production of human factor IX (hFIX) at a therapeutic level in SCID mice. Primary skeletal myoblasts were stably transfected with a hFIX expression plasmid vector, pdLMe4 betaA-hIXm1, which contains a hFIX minigene under the control of a beta-actin promoter with muscle creatine kinase enhancers. Myotubes derived from the myoblasts produced 1,750 ng hFIX/10(6) cells/24 hours in culture. hFIX secretion by the myoblasts and thereof derived myotubes were equally efficient, and myotubes were shown to have a sufficient secretory capacity to handle a substantially elevated production of hFIX. After intramuscular injection of 5, 10, and 20 x 10(6) myoblasts, SCID mice stably produced hFIX into the systemic circulation proportional to the number of implanted cells, and the expression levels were maintained for at least up to 10 months (end of the experiment). Additional cell injections administered to animals that originally received 10 x 10(6) cells approximately 2 months later elevated the systemic hFIX levels to an average of 182 +/- 21 ng/mL, a therapeutic level, which persisted for at least 8 months (end of the experiment). These results indicate that long-term, stable systemic production of hFIX at therapeutic levels can be achieved by repeated application of myoblast-mediated gene transfer.

Animals↗
PubMed1997

Clinical features of perineuritis.

We report 13 patients with pathologically confirmed perineuritis. Seven patients had diabetes mellitus, 5 had nutritional abnormalities, 2 had associated rheumatological illnesses, 2 had sepsis with multiorgan failure, and 1 had a history of malignancy. Electrophysiologic testing demonstrated mononeuritis multiplex in 7, demyelinating neuropathy in 4, distal sensory and motor neuropathy in 1, and polyradiculoneuropathy in 1. Twelve patients received immunomodulating therapy with variable responses. We conclude that perineuritis is associated with a number of different systemic conditions and several clinical patterns of peripheral neuropathy. Response to immunomodulation is variable. The most frequent association is with diabetes mellitus, a previously unrecognized association.

Adult↗
PubMed1997

Lymphocytic hypophysitis presenting with diabetes insipidus in a 14-year-old girl: case report and review of the literature.

UNLABELLED: Lymphocytic hypophysitis is a rare disorder predominantly affecting females during the antepartum or postpartum period. It is characterized by destruction and lymphocytic infiltration of the pituitary gland, probably by an autoimmune process, leading to a pituitary mass lesion and/or various degrees of hypopituitarism. The lesion is usually confined to the adenohypophysis. Posterior pituitary gland or stalk involvement is rare, although patients presenting with diabetes insipidus have been reported. We describe a girl aged 13 years 9 months with lymphocytic hypophysitis who presented with diabetes insipidus and secondary amenorrhea. MRI of the brain revealed a 1 cm enhancing mass in the pituitary stalk. A biopsy of the mass by right pterional craniotomy showed lymphocytic infiltration without neoplastic cells or granuloma formation. To our knowledge, this is the youngest reported patient with a diagnosis of lymphocytic hypophysitis. In this case report, her clinical presentation is discussed along with a review of the literature. CONCLUSION: We present the first childhood case of lymphocytic hypophysitis which is an autoimmune inflammatory disorder of the pituitary gland. Although this is a rare condition in adults, it also needs to be considered in the pediatric population. Conservative management is preferred unless there are signs of increased intracranial pressure. Most importantly, close monitoring for multiple hormone deficiencies is indicated in this condition.

Adolescent↗
PubMed1997

Leptomeningeal fibrosis and the delayed diagnosis of a central nervous system neoplasm (primitive neuroectodermal tumor).

We report a unique case of histologically confirmed meningeal fibrosis in a child who had progressive ischemic neurologic symptoms before the delayed diagnosis of an intracranial primitive neuroectodermal tumor (PNET) was made > 1 year after initial presentation. This pathology has previously been described after neurosurgical procedures, subarachnoid hemorrhage, cranial irradiation, and with no known etiology, but has never been reported in association with a central nervous system neoplasm. In a 6-year-old boy with headaches of several months' duration MRI demonstrated hydrocephalus, a right cerebellopontine angle cyst, and dural enhancement. Biopsies of the thickened meninges taken when the cyst was surgically fenestrated demonstrated only fibrosis with no evidence of infection, hemorrhage, or neoplasm. In the next 6 months, the child had two acute stroke-like episodes with alternating hemiparesis that gradually improved. There were ischemic changes in the diencephalon on MRI. Repeat dural biopsies were unchanged. One year after the initial operation, a left hemiparesis recurred and MRI demonstrated multiple intracranial masses in the cerebral cortex, cerebellum, suprasellar area, and cauda equina. After surgical resection, the cortical mass was found to be a PNET. All the lesions regressed after treatment with radiation and chemotherapy. We hypothesize that the meningeal fibrosis represented a "desmoplastic" reaction to an occult PNET, similar to the fibrous proliferation with cerebellar desmoplastic medulloblastoma except for the extent of the meningeal involvement and the long undetected parenchymal tumor. The mechanism of the ischemic brain injury was most likely vascular involvement by the fibrotic process, either directly or by predisposition to vasoconstriction.

Brain Neoplasms↗
PubMed1996

Craniopharyngioma: radiologic and histologic findings and recurrence.

PURPOSE: To identify the CT and MR characteristics of craniopharyngiomas, to evaluate the histologic types of craniopharyngioma, and to compare the radiologic/histologic appearance and type of therapy with tumor recurrence. METHODS: We reviewed the records of 45 patients with craniopharyngiomas for which surgical specimens (n = 45), preoperative MR or CT studies (n = 27), or other MR or CT studies or reports (n = 18) were available. Radiologic appearance, histologic morphology, treatment, and tumor recurrence were studied. RESULTS: Adamantinomatous epithelium was found in 40 of 45 surgical specimens, keratin in 34 of 45, and squamous epithelium in 11 of 45. A continuum of mixed morphology rather than distinct subtypes of tumors was found. The radiologic appearance did not correlate with the histologic features. No statistically significant difference was found between children and adults with respect to tumor size, calcification, histology, or tumor recurrence. Patients treated with radiation after subtotal resection had far fewer tumor recurrences (n = 3) than patients treated with surgery alone (n = 18). CONCLUSION: Craniopharyngiomas could not be divided into distinct histologic types. No differentiating radiologic or histologic characteristics could be established for craniopharyngiomas in children versus adults. Radiation treatment was strongly associated with tumor regression or lack of recurrence.

Adolescent↗
PubMed1995

Low grade gliomas: preliminary analysis of failure patterns among patients treated using 3D conformal external beam irradiation.

PURPOSE: The pattern of failure of low grade gliomas following radiotherapy is less well known than that of the high grade gliomas. Stereotactic histologic studies have suggested that tumor cells extend beyond imaging abnormalities, and that large margins would be required for radiotherapy target volumes to encompass all of the neoplasm. Our experience using computerized tomography (CT)- and magnetic resonance (MR)-planned irradiation of low grade gliomas was reviewed to determine the pattern of tumor recurrence, in an effort to clinically define the minimum margin required. METHODS AND MATERIALS: Forty-six patients with low grade supratentorial gliomas were treated between April 1985 and November 1992 using three-dimensional (3D) conformal CT- or MR-planned external beam radiotherapy. Fields were designed to encompass a target volume created by adding a margin to the tumor in three dimensions. Generally, patients were treated using shrinking fields with an initial target (tumor plus a 1 to 3 cm margin) treated to a dose of 45 to 50.4 (median 50.4) Gy, and a boost (tumor plus a 0 to 2 cm margin) treated to a total of 54 to 59.4 (median 59.4) Gy. Median follow-up was 32.9 months. RESULTS: There have been 11 failures; all of these occurred within the radiographic abnormality (either T2 prolongation or CT hypodensity) visualized at the time of treatment planning (i.e., all failures were within the boost volume). Median time to failure was 53 months. Because all failures were local, there was no relationship between the amount by which the tumor volumes were expanded to create target volumes and the eventual outcome. CONCLUSION: Despite pathologic data suggesting that low grade glioma cells can be found outside the MR T2-signal abnormality in many cases, our results demonstrate that conformal external beam radiotherapy, in which the high dose volume is limited, does not result in increased marginal or out-of-field failures. Until control of tumor within the radiographically abnormal volume can be achieved, the need for large fields to treat prophylactically microscopic disease beyond the visualized tumor volume is questionable. The use of conformal fields might be associated with reduced toxicity, and thereby allow delivery of higher total doses to the central tumor.

Adolescent↗
PubMed1995

Bone formation within a choroid plexus papilloma.

Bone formation within the choroid plexus papillomas is rare, with only 4 previous cases reported. We present a case of a 12-year-old boy who presented with papilledema, visual loss and hydrocephalus who was found to have a choroid plexus papilloma. Histological analysis of the tumor revealed foci of cancellous bone formation with hematopoietic cells within the marrow spaces. We review the proposed mechanisms for bone formation within neuroepithelial brain tumors.

Child↗
PubMed1994

Hereditary neuropathy with liability to pressure palsies masquerading as slowly progressive polyneuropathy.

Hereditary neuropathy with liability to pressure palsies (HNLPP) is a peripheral nerve disorder in which recurrent pressure palsies are associated with pathological swelling ('tomacula') of myelinated nerve internodes. We report a patient with a slowly progressive polyneuropathy associated with substantial slowing of conduction velocities initially suggestive of an acquired or hereditary demyelinating polyneuropathy. However, repeat electrodiagnostic studies demonstrated that conduction slowing and partial conduction block were localized primarily to common sites of nerve compression and entrapment. Sural nerve biopsy revealed multiple tomacula consistent with the diagnosis of HNLPP.

Diagnosis, Differential↗
PubMed1994

Utility of needle muscle biopsy in a university rheumatology practice.

OBJECTIVE: To evaluate the utility of percutaneous needle muscle biopsy (NMB) as an alternative to open biopsy for the evaluation of patients with myopathy encountered in a university hospital based rheumatology setting. METHODS: Chart review of all patients (n = 30) who underwent NMB at our institution over a 4-year period. Patients were grouped according to clinical outcome. Records of 91 patients who underwent open biopsy during the same period were reviewed for comparison. RESULTS: NMB results either confirmed or added to the prebiopsy diagnostic suspicion in 11 patients and excluded a low prebiopsy suspicion in 13, thus yielding useful clinical information in 24 of 30 patients (80%). Biopsy left the suspected diagnosis unresolved more frequently in patients undergoing NMB compared to patients who had open biopsy during the same time period (6/30 vs 1/91). In the 6 cases unresolved by NMB, subsequent open biopsy added additional information in only 2 of 5 patients. Sensitivity of NMB for inflammatory myopathy was 83% in the 23 patients suspected of having this disease. NMB could be arranged twice as fast as open biopsy, and provided adequate tissue for evaluation in all cases. CONCLUSIONS: Our results suggest that NMB is an effective tool for obtaining useful diagnostic information, particularly pertaining to the presence of an inflammatory myopathy. The convenience, low morbidity, and sensitivity of NMB make it a procedure worthy of wider application by rheumatologists.

Adult↗
PubMed1993

Low diagnostic yield of sural nerve biopsy in patients with peripheral neuropathy and primary amyloidosis.

Patients with primary amyloidosis may develop peripheral neuropathy as an early feature. Sural nerve biopsy is reported to be a sensitive method for diagnosing amyloidosis in such patients. We identified nine patients, ultimately diagnosed as having amyloidosis, who were referred for peripheral neuropathy of undetermined etiology. In six, a sural nerve biopsy demonstrated no amyloid. Subsequent examination of other tissue or of the contralateral sural nerve eventually resulted in the correct diagnosis. We conclude that sural nerve biopsy may be less sensitive than previously believed for the diagnosis of amyloidosis in patients with peripheral neuropathy secondary to amyloid. When the clinical suspicion of amyloidosis is high, a nondiagnostic sural nerve biopsy should not discourage the performance of further investigative studies.

Aged↗