Cerebellar venous infarction: case report with clinicopathologic correlation

A diabetic man developed a severe hyperosmolar state resulting in coma. CT of the head showed bilateral cerebellar hemorrhages. Despite medical treatment, he deteriorated and died. At autopsy, the straight sinus was thrombosed. There were bilateral, hemorrhagic, cerebellar venous infarctions. This condition is rare because of abundant collateral venous drainage.

Congenital difficulties with swallowing and breathing associated with maternal polyhydramnios: neurocristopathy or medullary infarction?

Two babies with congenital difficulties in swallowing and breathing are presented and contrasted. Both were associated with maternal polyhydramnios, but one was due to medullary infarction and the other to a malformation ("neurocristopathy"). In the former case, isolated tenth and twelfth cranial nerve palsies provided the clue as to the correct etiology, whereas the latter baby had dyscoordination of swallowing and breathing with sleep apnea ("Ondine's curse"). It is somewhat ironic that the case without a difficult delivery had the infarct, probably prenatal in onset, whereas the one with a difficult delivery had the congenital malformation. Neural crest cells are known to migrate widely and to develop greatly different functions, but the fact that their central associations of neural tube origin may also be affected has not previously been emphasized in the etiopathogenesis of the congenital malformation. A variety of syndromes with combinations of many defects may be seen in which too many or too few cells are formed, with more or less serious consequences especially for the respiratory and gastrointestinal systems.

Transsynaptic spread of varicella zoster virus through the visual system: a mechanism of viral dissemination in the central nervous system

We report a patient with pathologic evidence of anterograde spread of varicella zoster virus (VZV) through the visual system. A 29-year-old homosexual man developed the acquired immunodeficiency syndrome (AIDS) 2 months before the onset of left herpes zoster ophthalmicus. During the next 11 months, the zoster infection progressed to involve the left eye, with resultant keratitis, iritis, retinitis, and eventual blindness. Later, the patient developed bilateral blindness, left hemiparesis, and fatal pneumonia. At autopsy, the brain revealed destruction of the visual system and adjacent structures, with sparing of the remainder of the brain. Glial cells near the areas of necrosis showed Cowdry type A intranuclear inclusions. In situ hybridization with probes to VZV nucleic acid sequences were positive in the necrotic brain and retinal areas. Hybridization with probes to cytomegalovirus, herpes simplex virus type II, human immunodeficiency virus, and Epstein-Barr virus were negative. Electron microscopy revealed characteristic herpes group nucleocapsids. This case provides insight into the mechanisms of virus dissemination and the production of encephalitis.

Choroid plexus cysts in fetuses with trisomy 18

An association between fetal choroid plexus cysts and trisomy 18 has been suggested. However, the prevalence of such cysts in aneuploid fetuses is unknown. To determine this frequency, we studied 14 fetuses with trisomy 18 examined at the Central Laboratory for Human Embryology. Five fetuses were found to have choroid plexus cysts on postmortem ultrasound examination. All those with cysts were earlier than 26 weeks in gestation, and the prevalence among second-trimester fetuses was 71.4%. In contrast, such cysts are reported in less than 1% of the general population of second-trimester fetuses. Thus, choroid plexus cysts are common in trisomy 18, and the finding of such cysts on a second-trimester ultrasound examination should suggest further evaluation, including chromosome analysis.

Megalencephaly in sudden infant death syndrome

The fresh brain weights of 79 infants with sudden infant death syndrome (SIDS) were tabulated and compared with expected "normal" brain weights. The series included 47 males and 32 females. Their ages ranged from 8 days to 16 months with a median of 2.5 months. The weights of all these brains were above the 50th percentile for age, and 64 of 79 brains (81%) were above the 95th percentile, including 15 (19%) at or above the 99.9th percentile. The ratio of the brain stem plus cerebellum weight to the whole brain weight of 93 formalin-fixed brains from victims of SIDS showed that the cerebrum was disproportionately heavier in most cases. No gross or microscopic evidence of cerebral edema was noted to account for the heavier weight. The significance of these findings is debatable. The increase in brain weight was less obvious in infants younger than 1 month of age but accelerated after that age. The brain weights of infants with SIDS may represent the really "normal" weights, since these patients were not known to be ill prior to death. If the brain weights of SIDS infants are really heavier than "normal," the possibility must be considered that disproportionately rapid growth of the brain during early infancy may be detrimental to the neural control of the cardiorespiratory system.

Acute failure of forebrain with sparing of brain-stem function. Electroencephalographic, multimodality evoked potential, and pathologic findings

We describe a case of acute failure of forebrain with preservation of brain-stem function following cardiopulmonary arrest. This condition is distinguished from persistent vegetative or noncognitive states. Multimodality evoked potentials showed electroretinograms but no cerebral potentials to flash stimulation of both eyes; normal electrocochleograms and brain-stem auditory-evoked potentials to click stimulation of both ears; and Erb's point, N13, and P14 but no cortical responses to electrical excitation of both median nerves. Pathologic alterations consisted of pseudolaminar necrosis involving the whole cerebral cortex and other forebrain regions, with relative preservation of brain stem and spinal cord. Close correspondence existed between electrophysiologic, clinical, and major neuropathologic alterations.

Chronic remitting-relapsing experimental allergic encephalomyelitis induced in monkeys with homologous myelin basic protein

A chronic remitting-relapsing form of experimental allergic encephalomyelitis (EAE) has been produced in monkeys sensitized to homologous myelin basic protein in Freund's complete adjuvants by the technique of suboptimal treatment after the onset of disease. Not only does the clinical course resemble that of human multiple sclerosis more closely than does the clinical course of acute EAE, but so also does the histological reaction, with more-nearly pure demyelination, rather than the hyperacute hemorrhagic-necrotic lesions that occur so commonly in untreated monkeys with ordinary acute EAE.

Radiation, methotrexate, and white matter necrosis: laboratory evidence for neural radioprotection with preirradiation methotrexate

To investigate the interactions between methotrexate (MTX) and irradiation of the central nervous system, adult rats were infused with MTX via the lateral cerebral ventricle either before, during, or following single fraction irradiation to the cervical spine. Single doses ranging from 1600 cGy to 3200 cGy were administered and the dose-response curve for forelimb paralysis was compared with that seen in irradiated animals which did not receive MTX. There was no effect on the dose-response curve when MTX was administered simultaneously with or following irradiation compared to radiation alone. When MTX was given prior to irradiation, however, the entire dose-response curve shifted in the direction of radioprotection by approximately 225 cGy. Histopathologic examinations were consistent with this observation, with animals pretreated with methotrexate demonstrating significantly less white matter necrosis than observed in untreated controls. Protection of normal CNS tissue from radionecrosis, and from the associated paralysis, may be achieved with preradiation methotrexate.

Acute haemorrhagic leucoencephalitis with a prolonged clinical course

Two cases of pathologically proven acute haemorrhagic leucoencephalitis with clinical features resembling a cerebral tumour are reported. One patient with a left fronto-parieto-temporal mass showed progressive neurological deterioration leading to death in 3 months. Another patient with a right parieto-temporal mass had mild neurological symptoms for one and a half months before complete recovery except for a seizure disorder, following steroid and decompressive therapy. The cases show that acute haemorrhagic leucoencephalitis may not always be rapidly fatal, but may run a prolonged clinical course with recovery.

Multiple sclerosis beginning in infancy

The clinical and autopsy findings on a 6-year-old child presenting with 11 episodes of relapsing neurological symptoms since age 10 months are reported. The brain showed multiple and irregular demyelinative lesions in the cerebral and cerebellar white matter as well as in the tegmentum and base of the brain stem. This case reconfirms the existence of typical multiple sclerosis (MS) in childhood, beginning even in infancy. In addition, elevated Epstein-Barr virus antibody titers during the clinical course of this patient raise an interesting but still speculative etiological possibility for MS.

Human immunodeficiency virus (HIV) infection in brains with AIDS-related leukoencephalopathy

In addition to central nervous system (CNS) opportunistic infections and neoplasms, patients with acquired immunodeficiency syndrome (AIDS) develop unexplained dementia and encephalopathy and degeneration of the white matter. We studied autopsied brains from 20 adult patients who expired from AIDS to determine the relationship of human immunodeficiency virus (HIV) infection to white matter lesions and to clinical findings. In four patients with dementia/encephalopathy and abnormalities of the white matter, there was evidence of HIV infection as shown by in situ hybridization. In contrast, the remaining 16 patients who had no evidence of white matter degeneration revealed no hybridization to the HIV probe. The cells infected with HIV included endothelial cells, perivascular macrophages/monocytes, and multinucleated giant cells and were found in or adjacent to white matter degeneration. These results demonstrate a correlation between HIV-infected cells and AIDS leukoencephalopathy and provide further evidence for HIV-related dementia/encephalopathy.

Correlates of mental retardation and structural changes of the brain

Neuropathological findings are analyzed in 299 cases from 3 state institutions for mental retardation (MR) with or without cerebral palsy or seizures. Major lesions were found in 127 patients (42.5%): various forms of post-hypoxic encephalopathy, developmental anomalies, degenerative and metabolic diseases and post-infectious encephalopathy, all showing good clinicopathological correlations. Ninety-seven patients (32.5%) showed minor or non-specific lesions which could not be used to make a specific etiopathogenetic diagnosis and which appeared not concordant with the magnitude of the functional deficiency but nevertheless demonstrated structural imperfection of the brain. This group included subtle developmental anomalies, such as focal heterotopia, polymicrogyria, abnormal convolutional patterns and disproportionate subunits as in Down syndrome (45 cases; 15%) and subependymal germinolysis in which the etiology is varied. The most baffling and elusive group consisted of 75 cases (25%) showing no significant morphological abnormalities. Thirty-six of these had a history of seizures but 39 did not. The causes of MR in this group are heterogenous as in the group with major morphological lesions and may include unrecognized biochemical abnormalities, ultrastructural lesions, psychiatric disorders or cultural factors, but many still remain conjectural. It appears that a morphologically normal brain provides a potential for but does not ensure average functional development, but the reverse is not always true.

Electrical correlates of brain injury resulting from severe hypotension and hemodilution in monkeys

The effects of hypotension, hemodilution, and their combination on the relationship between concurrent brain electrical activity and resulting brain injury were studied in anesthetized monkeys. The authors compared changes in the electroencephalogram and somatosensory and auditory evoked potentials with eventual neuropathologic outcome. Our goals were: 1) to define the margin of safety for the monkey brain during hemodilution and hypotension under several simulated clinical conditions; and 2) to determine whether noninvasive measurements of brain electrical activity can predict ischemic brain cell damage. Forty-one monkeys were anesthetized with halothane (0.8 vol % inspired) and ventilated mechanically. Arterial hypotension was induced with trimethaphan (25 +/- 8 mmHg mean arterial blood pressure [MABP] for 30 min). Hemodilution was induced by replacing blood with lactated Ringer's solution (14 +/- 2% hematocrit for 1 h). Combined hemodilution and hypotension consisted of 30 min of hemodilution alone followed by superimposing hypotension for 30 min (16 +/- 3% hematocrit and 29 +/- 5 mmHg MABP). Ten monkeys died following severe hypotension alone or combined hemodilution and hypertension as a consequence of cardiac arrest or undetermined (possibly neurologic) causes. No histologic evidence of ischemic brain cell injury was found in surviving monkeys subjected to hemodilution or hypotension alone. Neuropathologic alterations in the cerebral cortex, cerebellum, hippocampus and globus pallidus as well as neurologic and behavioral deficits were found in seven of 16 surviving monkeys subjected to both hemodilution and hypotension. These findings resulted from combinations of hematocrit less than 20% and MABP below 40 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)

Histologic analysis of tissue response to bucrylate-pantopaque mixture

A toxicologic-pathologic study of isobutyl-2-cyanoacrylate (Bucrylate) was carried out first in dogs and then in humans whose arteriovenous malformations were infused with this embolic agent. The canine specimens obtained at 7, 18, 28, and 147 days after embolization showed the development of a mild histiocytic giant cell reaction, which evolved to end-state sclerotic arteritis. The response was confined to the vessels and did not involve contiguous parenchymal tissues. Ten human specimens, obtained from 1 hr to 7 years after treatment, showed a similar bland reaction with no evidence of suppuration or premalignant changes.

Progressive dementia and epilepsy in a young adult: unusual intraneuronal inclusions

A 30-year-old woman had a syndrome of dementia, dystonia, myoclonus, and intention tremor. Brain biopsy showed PAS-positive inclusions of Lafora's disease, but electronmicroscopy demonstrated that the inclusions differed from previously reported Lafora bodies. This may represent a previously undescribed disorder.

Health risks from increases in methylmercury exposure

Our present knowledge of the human health effects of methylmercury exposure is derived from study of major outbreaks of human poisonings in Japan and Iraq and experimental studies on primates. Methylmercury readily passes through such physiological barriers as the blood-brain barrier, blood-testes barrier, and the placenta. Its major pathological effects are on the nervous and reproductive systems and the developing embryo/fetus. The neurotoxicity of methylmercury is well established in both humans and non-human primates. Lesions in the cerebral and cerebellar gray matter consist of necrosis and lysis of neurons, phagocytosis and gliosis. The changes are most prominent in the deep sulci and may have a vascular component. A late effect is cerebral atrophy. At high dose levels the liver, kidneys, and other organs may also have degenerative changes. Although not yet described in humans, a major effect of exposure of female primates is an adverse effect on pregnancy. Maternal female M. fascicularis blood mercury levels above 1 ppm are associated with a decreased pregnancy rate and increased abortion rate. To date our experimental data lack sufficient numbers to detect infrequent pregnancy effects below 1 ppm. Preliminary studies also reveal that methylmercury may also decrease the number and function (swim speed) of sperm. Both human and primate studies demonstrate deleterious effects of methylmercury on the developing embryo/fetus. Autopsies on human and primate infants reveal retarded brain development and the occurrence of a cerebral palsy-like behavior in the newborns, whereas the mother may be free of signs and symptoms of methylmercury toxicity. The fetal blood level of mercury is higher than the maternal level.(ABSTRACT TRUNCATED AT 250 WORDS)

Iron pigment in the brain of a man with tardive dyskinesia

A 64-year-old man with bipolar affective disorder developed persistent tardive dyskinesia following an overdose of lithium and haloperidol. Two years later he died of unknown causes. Neuropathologic examination revealed extensive deposition of iron in basal ganglia and substantia nigra.

Prolactinomas as part of the multiple endocrine neoplastic syndrome type 1

The pituitary tumors seen in the multiple endocrine neoplastic syndrome type 1 have generally been considered "nonfunctional." Fewer than 40 persons with hyperprolactinemia as part of the syndrome have been described. A family with the largest number of subjects (six) with prolactinomas in one generation reported to date is described. The variable aggressiveness of this disease, the difficulty in treatment because of multiple prolactinomas or hyperplasia or both, and a case of tumor shrinkage with bromocriptine therapy are also demonstrated in this unique family.

A mixed functional microadenoma and ganglioneuroma of the pituitary fossa. Case report

✓ The authors describe a case of a mixed prolactin- and somatotropin-secreting pituitary adenoma and ganglioneuroma of the pituitary fossa in a patient with galactorrhea, hyperprolactinemia, and headaches. Histological and electron microscopic findings were typical for each element of the tumor, but the finding of a ganglioneuroma within the pituitary fossa is unusual; even more unusual was its proximity to an apparently unrelated tumor in the same location. The clinical, radiological, endocrinological, and pathological findings are discussed.

Computerized tomography as a diagnostic aid in acute hemorrhagic leukoencephalitis

Computerized tomography (CT) in a pathologically proven case of acute hemorrhagic leukoencephalitis (AHL) showed a mass effect and increased absorption coefficient in the right hemisphere within 18 hours of the onset of neurological symptoms. The changes corresponded to the site of white matter edema, necrosis, and petechial hemorrhages demonstrated postmortem. The early changes of CT reflect the hyperacute nature of AHL and differ from those of herpes simplex encephalitis.

Profound arterial hypotension in dogs: brain electrical activity and organ integrity

To determine whether non-invasive measurement of brain electrical activity can predict ischemic brain damage, we recorded the electroencephalogram (EEG) and somatosensory- (SEP) and auditory- (AEP) evoked potentials before, during, and after trimethaphan-induced profound arterial hypotension in dogs. The authors set out to compare the change in electrical activity with the degree of brain damage, as determined by microscopic examination. Dogs were anesthetized with halothane (1.4 vol % inspired), maintained horizontal (head at the level of the heart), and ventilated mechanically (FIO2 0.50); deviations from normal acid-base status were corrected. Twenty animals received a 1.5-mg/kg intravenous bolus of trimethaphan. Three animals were resistant to the drug. The remaining animals had profound hypotension [mean arterial blood pressure (MABP) at some steady level between 12 and 25 mmHg] for 1 h. Eight of these animals died during or soon after the hypotensive period as a consequence of cardiac arrest (three), intestinal bleeding (three) or unknown causes (two). In all survivors, EEG intensity and the amplitude of the SEP decreased during hypotension; both variables recovered with restoration of MABP. All nine animals surviving hypotension had no apparent neurologic or behavioral deficit nor any histologic evidence of ischemic brain cell injury. We were thus unable to find a MABP threshold for brain with minimal brain injury. Our findings suggest, under the conditions of our experiments, a great margin of tolerance for profound hypotension by the brain in this species. Other organ systems--the heart, gastrointestinal tract, and liver--proved to be more susceptible to ischemic damage. Eight of the nine surviving animals had elevations in serum alanine transaminase (SGPT), aspartate transaminase (SGOT), and alkaline phosphatase. Animals with the greatest increases in these enzymes showed centrilobular hepatocyte degeneration.

Immediate and delayed neurotoxicity after mechlorethamine preparation for bone marrow transplantation

Twenty-four patients, including two with aplastic anemia and 22 with malignancy, underwent marrow transplantation after preparation with mechlorethamine, 0.3 to 2.0 mg/kg body weight. Fourteen of the 21 neurologically evaluable recipients developed immediate neurotoxicity a median of 4 days after treatment (range, 0 to 34 days). Confusion and disorientation were observed in six patients, headache in six, hallucinations n four, lethargy in four, tremors in three, paraplegia in one, seizure in one, and vertigo in one. Whereas acute symptoms cleared in 11 patients, three remained symptomatic until death. Twelve evaluable patients survived more than 60 days; all six with previous acute toxicity subsequently developed delayed onset of new neurologic findings (personality change, confusion, seizure, diplopia, or dementia) a median of 169 days (range, 70 to 248 days) after treatment. Cerebrospinal fluid analysis was usually normal but cerebral computed tomographic scans showed ventricular enlargement and electroencephalograms showed diffuse slowing. Postmortem histologic examination of brain showed neuronal degenerative changes with increased vascularity, gliosis, and perivascular fibrosis. Neurotoxicity appeared to increase with age and mechlorethamine dose and was commoner in patients given additional procarbazine or cyclophosphamide.

Pathogenic mechanisms of heterotopic neural tissue associated with anencephaly

Central nervous tissue was found in both the lung and the abdominal surface of the diaphragm in an anencephalic baby with gastroschisis. These findings support the hypothesis that the heterotopic neural tissue in anencephalic babies is due to transamniotic implantation. It thus appears that the pathogenic mechanism of the heterotopic neural tissue in the lung is aspiration.

Bleeding patterns from ruptured intracranial aneurysms: an autopsy series of 205 patients

The autopsy records from 205 patients who died from ruptured intracranial aneurysms were reviewed. Special emphasis was placed on the cause of death and the time after rupture that death occurred. One hundred and sixty-eight patients (82%) died within one week of their last aneurysmal rupture. Eighty-eight died within one week of their initial rupture. Massive subarachnoid hemorrhage was the cause of death in 53% and localized hematomas in 14%. Eighty patients died within one week following a subsequent rupture. Intracranial hematoma was the cause of death in 87%, with 31% harboring a localized mass potentially amenable to surgical therapy.

True traumatic aneurysm of the vertebral artery: case report

A patient is reported in whom a true aneurysm of the vertebral artery developed following head trauma. The histology of the aneurysm and parent vessel is presented, and its implications regarding the mechanism of formation of posttraumatic true aneurysms are discussed.

Has myelin basic protein received a fair trial in the treatment of multiple sclerosis?

Autosensitization to some central nervous system antigen still remains one of the best hypotheses for the continuing pathogenesis of multiple sclerosis (MS). Enough is now known about the cause, pathogenesis, and treatment of experimental allergic encephalomyelitis (EAE) to test this hypothesis. Reports of therapeutic failure of the encephalitogen myelin basic protein (BP) in the treatment of MS have their counterparts in similar therapeutic failures in EAE. Only highly inbred strain 13 guinea pigs respond consistently to BP therapy, and this only when BP is administered in relatively high doses. Noninbred guinea pigs respond much less well to simple BP therapy, and monkeys hardly at all. In both strains of monkeys so far studied, a nonspecific adjunctive factor--an antibiotic in Macaca mulatta and a steroid in Macaca fascicularis--is also required. Accordingly, human trials of the therapeutic efficacy of BP in MS should include its administration in large concentrations together with an adjunctive agent.

Myelin basic protein treatment of experimental allergic encephalomyelitis in monkeys

Treatment of experimental allergic encephalomyelitis (EAE) in two strains of monkeys with large amounts of myelin basic basic protein (BP) fails unless an adjunct is also used. In both strains the adjunct by itself is more effective than BP by itself, but in the one strain which could be investigated sufficiently, the combination can be made almost totally effective in reversing EAE. The adjunct varies with the strain of monkey, an antibiotic in Macaca mulatta and a steroid in Macaca fascicularis. Similar adjunctive treatments should be considered in the management of multiple sclerosis, for EAE remains one of the best studied models.

The pathology of occipital encephalocoele and a discussion of the pathogenesis

The midline structures of 5 infant brains with occipital encephalocoeles were studied. Though all cases showed a uniform finding of a midline defect of the occipital bone with a herniated mass, the extent of the bony defect, the amount and nature of the herniated tissues and the degree of distortion of the intracranial structures varied markedly. Two of the cases showed multiple associated systemic malformations and another case had an inverse cerebellum. In spite of such a marked variability in presentation, the common findings of herniation and displacement of the mesencephalon and roof of the diencephalon allowed us to postulate that the primary defect of occipital encephalocoeles is an abnormality of the tissues overlying the mesencephalon of the developing brain. Initial herniation of the mesencephalon and subsequent movement of the rest of the brain as a result of growth determines the tissues present in the hernia sac at birth. Other theories of genesis of occipital encephalocoeles are discussed.

Fast-neutron irradiation of glioblastoma multiforme. Neuropathological analysis

Various modes of therapy, alone or in combination, have had little effect in improving the survival of patients with glioblastoma multiforme. Recently, in a pilot study, 34 patients with glioblastoma were treated by fast-neutron-beam irradiation of the whole brain. Following treatment, the patients became steroid-dependent and pursued a gradual downhill course with increasing obtundation. Although there was no improvement in the length or quality of survival of these patients, neuropathological studies in the 13 patients who came to autopsy showed the following: 1) extensive coagulative necrosis of much of the tumor mass; 2) dense infiltration by collagenous connective tissue; 3) minimal phagocytic reaction; 4) marked reduction in the amount of viable tumor; 5) abnormal astrocytic proliferation, which may represent either astrocytoma or a radiation-induced bizarre gliosis, and 6) areas of gliosis and white matter degeneration in the brain stem, remote form the tumor site. These observations suggest that continued efforts to further refine this mode of therapy for glioblastoma are warranted.

The microbiology of a new recirculatory automatic watering system compared with a conventional automatic system

Continual recirculation and filtration of drinking water prevents the contamination that often mars automatic watering systems by removing algae and fluorescent pseudomonads. Without filtration and recirculation, the algae were clearly visible after 40 days use, and the fluorescent pseudomonad count rose from 10(1) to 10(5) per ml after 72 h use.

Progressive myoclonus and epilepsy with dentatorubral degeneration: a clinicopathological study of the Ramsay Hunt syndrome

Ramsay Hunt's progressive myoclonus and epilepsy associated with dentatorubral degeneration is a rare disorder. We report a 19 year old woman with this clinical syndrome who also has a more mildly affected brother. Neuropathological in addition to dentatorubal involvement. The evidence suggests that this is a distinctive hereditary disorder producing neuromal degeneration at several levels in the central nervous system.

Phenytoin-related cerebellar degeneration without seizures

Cerebellar changes have been reported in relationship to epilepsy alone as well as to phenytoin therapy for the control of seizures. The cliniconeuropathological correlation between these changes and epilepsy or the anticonvulsant is usually complicated by the presence of both variables. Experimental evidence suggests that phenytoin alone may be sufficient to cause cerebellar changes following intoxication. We report a case of cerebellar degeneration in a patient treated with isoniazid and prophylactically treated wtih phenytoin who never had a seizure.

Chronic methylmercury exposure in the monkey (Macaca mulatta). Behavioral test of peripheral vision, signs of neurotoxicity, and blood concentration in relation to dose and time

Small daily doses of methylmercury hydroxide were administered to rhesus monkeys for periods of up to 17 months. Behavioral tests of peripheral vision and of the accuracy and rapidity of hand movements did not disclose any early subtle deficits preceding the onset of obvious signs of neurotoxicity. These signs appeared suddenly and involved reduced food intake (anorexia), clumsiness of jumping, loss of fine control of the digits, and uncoordinated mastication. With a constant daily dose of 0.1 mg/kg or less, blood concentration of mercury reached a peak after about 2 months, and then decreased to about half the peak value. Subsequently, increasing the daily dose level above 0.1 mg/kg (range of 0.12-0.21 mg/kg) produced an increase of blood concentration which tended to stabilize in the range of 2.0-2.5 ppm. After several months at these elevated concentrations all animals exhibited signs of neurotoxicity.

Fast neutron beam radiotherapy of glioblastoma multiforme

Twenty-one patients with glioblastoma multiforme were treated with fast neutron beam irradiation of the whole brain. Therapy was well tolerated up to calculated doses of 1.850 radn+y in 12-18 increments over 6 weeks. The survival rate 6 month after initiation of treatment was 62%, not significantly different from conventional photon therapy; average posttreatment survival appears to be shortened compared to photon therapy. No improvement or prolonged maintenance of existing neurologic function was observed. Autopsy findings in seven patients showed replacement of tumor by coagulative necrosis persisting at least 16 months posttreatment, paucity of tumor cells with infrequent mitosis, and suppression of macrophage response. These findings differ from those in conventionally irradiated patients. No treatment-related changes were documented by conventional gross and histologic studies of the irradiated brains distant from the tumors. Thus the deaths of patients in this study appear to be related to unexplained causes other than progressive growth of tumor.

Herpesvirus hominis encephalitis and retinitis

A previously healthy 44-year-old man died three weeks after the simultaneous onset of encephalitis and retinitis. Fundus changes were bilateral and included papillitis, rapidly progressive central retinal vein obstruction, and massive exudative retinal detachment. A 16-fold rise in herpesvirus hominis antibodies occured between the 10th and 20th days of illness. At autopsy, the brain showed changes characteristic of herpetic encephalitis, and cultures of the brain yielded Herpesvirus hominis type I. Intranuclear inclusion bodies typical of those produced by Herpesvirus were found by light microscopy in brain, optic nerves, retina, and choroid. Herpesvirus particles were found by electron microscopy in brain, optic nerve, and retina.

Do neurological signs occur in experimental allergic encephalomyelitis in the absence of inflammatory lesions of the central nervous system?

Guinea pigs with paralysis or other severe neurological signs of experimental allergic encephalomyelitis (EAE) always exhibited typical histological inflammatory lesions. A few animals inoculated with either the encephalitogenic emulsion or only the control adjuvant emulsion had mild weakness or slowness but no histologic lesion. In some instances, these signs were explained by coincidental non-neural disease or trauma. Therefore, such mild clinical signs cannot be considered pathognominic of EAE. Reports from the literature suggesting that animals have developed clinical signs without histological lesions in EAE are considered invalid because of the nonspecificity of clinical signs, the occurrence of intercurrent diseases, the inadequacy or incorrect timing of histologic evaluations, and the lack of controls for specificity of the signs. There is no basis for the supposition that autoimmunity can cause major neurological signs in the absence of inflammatory lesions in the nervous system.

Variability of neuropathologic lesions in experimental methylmercurial encephalopathy in primates

Acute and chronic intoxications of rhesus monkeys with methylmercury produced lesions in the central nervous system (CNS) with different distributions. Neuronal degeneration and astroglial proliferation predominated in the dentate nucleus, lateral geniculate nucleus, thalamus and pontine nuclei in 2 monkeys that received 2 mg/kg/day for 17 and 18 days, whereas pseudolaminar necrosis and astroglial proliferation were observed in the cerebral crotex, maximally in the calcarine and insular regions, in 4 monkeys that received 0.5 to 0.8 mg/kg/day for 3 to 8.5 months. Mercury concentrations in the CNS were much higher in the acutely intoxicated animals than in the chronically intoxicated animals, but the correlation between concentrations of mercury and the histologic destruction was not precise.

Injury of the basilar artery associated with closed head trauma

The neuropathological findings at necropsy are described in three cases of basilar artery injuries and their consequences after head trauma and the mechanism of injuries is discussed. The first case was that of massive pontine infarct due to an occlusion of the basilar artery trapped in the fracture of the clivus, 13 days before death. The second case, also with a pontine infarct, survived for two and two-thirds months; the trauma was probably similar, but the presence of the basal skull fracture and the occlusion of the basilar artery can be surmised only in retrospect. The third case was one of delayed rupture of the basilar artery occurring three to four weeks after the injury, which caused aneurysmal formation in the left posterior cerebral artery.