Prolactin and carcinoma of the breast.
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Adenoma↗
Biomedical subjects
A J Martinez
Publications and source records attributed to A J Martinez.
Effect of endothelin on plasma volume and albumin escape.
Previous studies have demonstrated that endothelin-1 (ET-1) is a potent vasoconstrictor that decreases cardiac output and increases hematocrit. The present study was designed to determine if the rise in hematocrit and decrease in cardiac output are in part due to shifts of plasma from the vascular space to the interstitial space. Red blood cell volume and plasma volume were determined by using chromium-51-labeled erythrocytes and iodine-125-labeled albumin, respectively, in anesthetized, nephrectomized, splenectomized rats. The present study demonstrates that ET-1 increases mean arterial pressure and hematocrit. This effect is associated with an increase in total-body albumin escape, which is reflected by a marked reduction in whole-body plasma volume. ET-1 enhanced albumin escape primarily in the liver, lung, and heart at low doses. At high doses, albumin escape increased primarily in the liver, heart, and gastrointestinal tract but not the lung. The present study demonstrates that ET-1 increases hematocrit independent of splenic contraction or renal losses by enhancing loss of plasma volume to the interstitial space without affecting red blood cell volume. Because of the profound pressor effects of ET-1, it is likely that the plasma loss results from increased capillary hydrostatic pressure.
Animals↗
Radiobiologic models for radiosurgery.
A series of initial radiobiologic investigations have been performed using three animal models. The baboon model proved to be a valuable technique to assess the in vivo radiobiologic response of single-fraction irradiation doses delivered to the primate brain stem. Multimodality neurodiagnostic testing, including CT, MR imaging, xenon-enhanced CT, evoked potential studies, and analysis of CSF myelin basic protein levels, all of which eventually were correlated with neuropathologic examination, enabled detection of lesions produced with high-dose (150 Gy) radiosurgery as early as 6 weeks. Within the first 6 months after radiosurgery, lower doses (20 Gy, 50 Gy) did not result in clinically or neurodiagnostically detectable lesions. The rat arteriovenous fistula model permits analysis of the delayed histopathologic effects of radiosurgery on an experimentally created fistula designed to mimic an AVM. The rat C6 glioma model is designed to evaluate the effect of radiosurgery in an infiltrative tumor that simulates a human malignant brain tumor. These studies are intended eventually to increase our knowledge about the safety and efficacy of radiosurgery in both the normal and tumor-implanted brains. We believe that such fundamental studies ultimately will improve our ability to reach the goals of radiosurgery: to destroy the target and spare the surrounding brain. Eventually, it may become feasible to achieve these goals by combining radiosurgical technique with both radiation sensitizers (for the treated volume) and brain protectors.
Animals↗
Neuropathologic and neurochemical correlates of psychosis in primary dementia.
Neuropathologic and neurochemical correlates of psychosis were determined using brain tissue from 27 autopsy-confirmed cases of Alzheimer's disease. The densities of senile plaques and neurofibrillary tangles were determined in the middle frontal and superior temporal cortex, the prosubiculum, and the entorhinal cortex of the hippocampus. The concentrations of norepinephrine, dopamine, and serotonin, the metabolites of these biogenic amines, and the specific activity of choline acetyltransferase were also determined in these four cortical regions as well as in the substantia nigra, thalamus, amygdala, and caudate nucleus. Psychosis was associated with significantly increased densities of senile plaques and neurofibrillary tangles in the prosubiculum and middle frontal cortex, respectively, with trends toward increased densities of these lesions in the other areas examined. This finding is consistent with the increased rate of cognitive decline that accompanies this behavioral disorder. Psychosis was also associated with the relative preservation of norepinephrine in the substantia nigra, with trends in this direction for five of the remaining seven brain regions examined, and a significant reduction of serotonin in the prosubiculum that was accompanied by trends toward reduced levels of serotonin and 5 hydroxyindoleacetic acid in the remaining regions. The profile of neuropathologic and neurochemical changes associated with psychosis is distinct from that previously reported for major depression in the context of primary dementia.
Aged↗
Neurological and neuropathological sequelae of correction of chronic hyponatremia.
The effect of correction of chronic hyponatremia at different rates was studied in 91 rats maintained at a plasma [Na+] of 112 +/- 1 mmol/liter for 19 +/- 1 days. Hyponatremia was corrected into normal ranges (140 to 145 mmol/liter) using three different methods. Rats corrected by water restriction achieved normal plasma [Na+] by 2.1 +/- 0.2 day and had a maximal (4 hr) correction rate of 1.0 +/- 0.1 mmol/liter.hr; rats corrected by water diuresis achieved normal plasma [Na+] by 1.6 +/- 0.1 day and had a maximal correction rate of 2.8 +/- 0.2 mmol/liter.hr; rats corrected by hypertonic saline infusion achieved normal plasma [Na+] by 5.4 +/- 0.3 hr and had a maximal correction rate of 5.7 +/- 0.4 mmol/liter.hr. A fourth control group was not corrected. No demyelinative lesions were found in the brains from the uncorrected rats, whereas the occurrence of such lesions in the brains of the corrected rats was highly correlated with the maximal rate of increase in plasma [Na+] (r = 0.68, P less than 0.001), and to a lesser degree with the magnitude of the increase in plasma [Na+] over the first 24 hours of correction (r = 0.41, P less than 0.001). Brain myelinolysis was first observed in animals whose maximal (4 hr) rate of correction exceeded 1.75 mmol/liter.hr, and the incidence of demyelination increased progressively in rats with more rapid rates of correction. Similarly, myelinolysis was first observed in rats whose magnitude of correction at 24 hours exceeded 16 mmol/liter and also increased in rats with larger 24 hour magnitudes of correction.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Tears of the glenoid labrum: MR imaging of 88 arthroscopically confirmed cases.
Two hundred eighty-one patients underwent magnetic resonance (MR) imaging of the shoulder over a 2-year period. Eighty-eight patients underwent arthroscopic surgery, and their surgical results were correlated with the findings at MR imaging. MR imaging enabled accurate prediction of anterior labral tears, with a sensitivity of 95%, a specificity of 86%, and an accuracy of 92%. MR imaging was less effective in the prediction of tears of the superior labrum, with a sensitivity of 75%, a specificity of 99%, and an accuracy of 95%. These two categories accounted for the majority of the surgically correctable disease. MR imaging was found to be unreliable in the prediction of posterior (sensitivity, 7.7%) or inferior (sensitivity, 40%) labral tears, isolated cases of which occurred in only two (2%) of those undergoing surgery. MR imaging proved to be a highly accurate, noninvasive technique for the clinical evaluation of shoulder instability.
Adolescent↗
Granulomatous amebic encephalitis in an AIDS patient.
A 39-year-old man with AIDS died after developing a variety of neurologic symptoms and signs. CT showed multiple enhancing lesions in the cerebral hemispheres and cerebellum. Postmortem examination revealed parenchymal hemorrhagic and necrotizing lesions with a thrombo-occlusive vasculitis due to Acanthamoeba, which was typed as Acanthamoeba group 2, probably A rhysodes, by immunofluorescence.
Acanthamoeba↗
Necrotizing angiopathy presenting with multifocal conduction blocks.
We describe conduction block as an unusual electrophysiologic manifestation in a patient with necrotizing angiopathy. The patient developed subacute symptoms over a 1-month period consisting of progressive pain, tingling, and weakness of the lower extremities. Physical examination revealed a pattern consistent with a polyneuropathy. Electrodiagnostic studies provided evidence of a conduction block in the left ulnar nerve. Pathologic studies confirmed the process to be a necrotizing angiopathy. This report establishes the role of conduction block in human nerve ischemia.
Electrodiagnosis↗
Cerebrovascular complications after orthotopic liver transplantation: a clinicopathologic study.
We analyzed 55 autopsy cases in 1,357 patients undergoing orthotopic liver transplantation at the University of Pittsburgh and found that 13 (23.6%) patients had intracranial bleeding, and five (9%) had infarcts. Eight patients had bleeding localized to one intracranial compartment: intracerebral hemorrhage (three patients); subarachnoid hemorrhage (three patients); and subdural hematoma (two patients). Five patients had combinations of multiple sites of bleeding: three with subarachnoid hemorrhage-intracerebral hemorrhage, one with subarachnoid hemorrhage-intracerebral hemorrhage-subdural hematoma, and one with subdural hematoma-intracerebral hemorrhage. Coexistent CNS infections (fungal or bacterial) were associated with hemorrhagic infarcts and intracerebral hemorrhage in four patients. Cerebral embolism and hemorrhagic infarction from bacterial endocarditis occurred in one patient. Five patients died of intracranial bleeding. Severe coagulopathy was the major cause of intracranial bleeding and was associated with systemic bleeding in 12 patients. Significant systemic or metabolic complications were present in all patients and masked the focal signs of the intracranial process in more than one half.
Adult↗
A vascular malformation mimicking an intracanalicular acoustic neurilemoma. Case report.
A patient with an enhancing, completely intracanalicular mass on magnetic resonance imaging was operated on for a presumed acoustic neurilemoma, but was found at surgery to have an intracanalicular vascular malformation. This rare lesion should be distinguished from angiomatous change within an acoustic neurilemoma and in the past has been termed "vascular tumor," "hemangioma," or "fibro-angioma." The clinical distinctions between intracanalicular acoustic neurilemomas and intracanalicular vascular malformations and the ability of magnetic resonance imaging to distinguish between the two are discussed.
Adult↗
Neuropathologic findings in liver transplantation: a comparative study of cyclosporine and FK 506.
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Adult↗
Laboratory diagnosis of pathogenic free-living amoebas: Naegleria, Acanthamoeba, and Leptomyxid.
Pathogenic free-living amebae of the genera Naegleria, Acanthamoeba, and Leptomyxid are still unfamiliar to pathologists, clinicians, and public health workers. These amebae are distributed worldwide in fresh water, dust, soil, sewage, and air conditioning units. The diagnosis, identification, and culture of the amebae, and risk factors, clinical manifestations, and histopathologic features of the diseases produced by these amebae are reviewed in this article.
Acanthamoeba↗
Atrial natriuretic factor blocks the pressor action of endothelin.
The present study was designed to determine the pharmacologic effects of rat atrial natriuretic factor (r-ANF; 250 ng/kg/min), endothelin-3 (ET-3; 340 ng/kg/min), and combined r-ANF and ET-3 infusion on cardiac hemodynamics and renal function in anesthetized rats. The change in mean arterial pressure (delta MAP) was 13 +/- 2 mm Hg during ET-3 infusion alone. Delta MAP was -9 +/- 2 mm Hg during r-ANF infusion alone. Combined infusion of ET-3 and r-ANF resulted in a change in MAP of -7 +/- 3 mm Hg. The decrease in MAP during combined infusion of ET-3 and r-ANF occurred due to a decrease in cardiac output. Infusion of r-ANF did not block the cardiac output. Infusion of r-ANF did not block the ET-3-induced increase in total peripheral resistance (TPR). Infusion of r-ANF alone resulted in an 11-fold increase in urinary sodium excretion. ET-3 infusion completely blocked the ANF-induced natriuresis in part by markedly decreasing the glomerular filtration rate (GFR). ET-3 or r-ANF infusion alone resulted in two- or eightfold increases, respectively, in circulating r-ANF levels compared to vehicle alone. However, combined infusion of r-ANF and ET-3 resulted in a dramatic 27-fold increase in circulating r-ANF when compared to levels obtained during vehicle infusion alone. The present study demonstrates that at pharmacologic levels, r-ANF blocks the pressor action of ET-3 by decreasing cardiac output rather than TPR. Furthermore, ET-3 blocks the natriuretic action of r-ANF, partly by decreasing GFR.
Anesthesia↗
In vivo biological effects of stereotactic radiosurgery: a primate model.
Single-fraction, closed skull, small-volume irradiation (radiosurgery) of intact intracranial structures requires accurate knowledge of radiation tolerance. We have developed a baboon model to assess the in vivo destructive radiobiological effects of stereotactic radiosurgery. Three baboons received a single-fraction, 150-Gy lesion of the caudate nucleus, the thalamus, or the pons using the 8-mm diameter collimator of the gamma unit. Serial standard neurodiagnostic tests (neurological examination, computed tomographic scan, magnetic resonance imaging, stable xenon-enhanced computed tomographic scan of cerebral blood flow, somatosensory and brain stem evoked potentials, and myelin basic protein levels of cerebrospinal fluid) were compared with preoperative studies. Magnetic resonance imaging revealed the development of a lesion at the target site between 45 and 60 days after irradiation. Deterioration of the brain stem evoked potentials preceded imaging changes when the lesion encroached on auditory pathways. Myelin basic protein levels increased subsequent to imaging changes. Postmortem neuropathological examination confirmed a well-demarcated radionecrosis of the target volume. The baboon model appears to be an excellent method to study the in vivo biological effects of radiosurgery.
Animals↗
Pure theca cell tumors. A clinicopathologic study of 29 cases.
From 1976 to 1989, 29 cases of ovarian theca cell tumors were diagnosed at the Pathology Department of our Hospital. Their clinical and histologic features were reviewed. The main presenting symptom in postmenopausal patients was uterine bleeding, whereas in premenopausal women, abdominal swelling and the findings of ultrasonographic examination were the diagnostic keys. Different surgical procedures were the cornestone of treatment, although in 12 cases the indication for surgery was not apparently related to an adnexal condition.
Adolescent↗
Invasive pituitary adenoma with abscess formation: case report.
A case is presented and 10 cases are reviewed in which abscess formation developed in an intrasellar tumor. The diagnosis was made preoperatively or before autopsy in only 1 patient. The mortality rate was greater than 50%. The most common presentation was headache, fever, and visual disturbances with an abnormal sella and sterile cerebrospinal fluid (CSF). Nonconstant findings included meningeal signs and leukocytosis of the CSF. Trans-sphenoidal removal of the tumor and drainage of the abscess with appropriate antibiotic therapy is recommended. (Neurosurgery, 5: 718--722, 1979).
Adenoma, Chromophobe↗
Arterial cross compression of the trigeminal nerve at the pons in trigeminal neuralgia. Case report with autopsy findings.
The autopsy findings in a patient with trigeminal neuralgia who died from unrelated causes are presented. Arterial cross compression of the appropriate trigeminal nerve at the pons was demonstrated. The relationship of arterial cross compression to trigeminal neuralgia is briefly discussed.
Aged↗